,,am]ican ,,sci5ce ,,s]ies--,,advanc$ ,,c\rse ,,geology ,,by ,,?omas ,c4 ,,*amb]l9 ,,& ,,roll9 ,d4 ,,salisbury ,heads ( ! ,dep>tm5ts ( ,geology & ,geography1 ,univ]sity ( ,*icago ,memb]s ( ! ,unit$ ,/ates ,geological ,survey ,editors ( ! ,j\rnal ( ,geology ,,9 ,,?ree ,,volumes ,,vol4 ,i4--,,geologic ,,processes ,,& ,,_! ,,results ,,second ,,edition1 ,,revis$ ,illu/ration ,,new ,,york ,,h5ry ,,holt ,,& ,,company #aiji ,copyright1 #aijd1 ,,by ,,h5ry ,,holt ,,& ,,company ,,pr9t$ ,,9 ,,! ,u4 ,s4 ,a4 ,,preface4 ,9 ! prep>ation ( ?is "w x has be5 ! purpose ( ! au?ors to pres5t an outl9e ( ! sali5t features ( geology1 z n[ develop$1 encumb]$ z little z possible by te*nicalities & details ^: be>+s on ! g5]al !me are unimportant4 ,9 common ) mo/ writ]s ( text-books on geology1 ! au?ors believe t ! subject is be/ approa*$ by a /udy ( ! =ces & processes n[ 9 op]ation1 & ( ! results :i* ^! =ces & processes are n[ br++ ab\t4 ,su* /udy necess>ily involves a consid]ation ( ! pr9ciples :i* gov]n ! activities ( geologic ag5cies4 ,^! topics are pres5t$ 9 ,volume ,i1 & prep>e ! way = ! /udy ( ! hi/ory ( pa/ ages1 :i* is outl9$ 9 ,volume ,,ii4 ,! g5]al plan ( ! "w has be5 det]m9$ by ! exp]i5ce ( ! au?ors z in/ructors4 ,little emphasis is laid on ! commonly recogniz$ subdivisions ( ! sci5ce1 su* z dynamic geology1 /ratigraphic geology1 physiographic geology1 etc4 ,! treatm5t proce$s r f ! po9t ( view t ! sci5ce is a unit1 t its "o !me is ! hi/ory ( ! e>?1 & t ! discussions ( dynamic geology1 physiographic geology1 etc41 ap>t f _! hi/orical be>+1 lose mu* ( _! significance & int]e/4 ,! ef=t has1 !re=e1 be5 to emphasize ! hi/orical elem5t1 ev5 9 ! discussion ( special !mes1 su* z ! "w ( riv]s1 ! "w ( sn[ & ice1 & ! orig9 & desc5t ( rocks4 ,?is does n mean t phases ( geology o!r ?an hi/orical h be5 neglect$1 b x means t an ef=t has be5 made to give a hi/orical ca/ to all phases ( ! subject1 s f> z ! topics p]mit4 ,?r\gh\t ! "w ! c5tral purpose has be5 n m]ely to set =? ! pres5t /atus ( k1 b to pres5t x 9 su* a way t ! /ud5t w be introduc$ to ! me?ods & _s ( ! sci5ce1 l$ to a sympa!tic int]e/ 9 its progress1 & prep>$ to receive intellig5tly1 & to welcome cordially1 its future advances4 ,:]e practicable1 ! text has be5 s %ap$ t ! /ud5t may foll[ ! /eps :i* h l$ to pres5t conclusions4 ,to ?is end ! work+ me?ods ( ! practical geologi/ h be5 impli$ z frequ5tly z practicable4 ,to ?is end also !re has be5 frankness ( /atem5t relative to ! limitations ( k & ! unc]ta9ty ( _m t5tative conclusions4 ,9 ^! & 9 o!r respects1 ! purpose has be5 to take ! /ud5t into ! frat]nity ( geologi/s1 & to reveal to him ! true /ate ( ! developm5t ( ! sci5ce1 giv+ an accurate & proportionate view ( ! positive k atta9$1 ( ! problems yet unsolv$1 or b p>tially solv$1 & ( solutions /ill to be atta9$4 ,! !oretical & int]pretative elem5ts :i* ent] into ! g5]al conceptions ( geology h be5 freely us$1 because !y are reg>d$ z an ess5tial "p ( ! evolution ( ! sci5ce1 because !y (t5 help to cle> & complete conceptions1 & because !y /imulate ?\ght4 ,! aim has be51 h[ev]1 to *>act]ize hypo!tical elem5ts z su*1 & to avoid confus+ ! int]pretations bas$ on hypo!sis1 ) ! /atem5ts ( fact & e/abli%$ doctr9es4 ,especial c>e has be5 tak5 to recognize ! unc]ta9 nature ( preval5t int]pretations :5 !y are dep5d5t on unv]ifi$ hypo!ses1 especially if ?is dep5d5ce is likely to be ov]look$4 ,if ?is %all seem to give prom95ce to ! hypo!tical elem5t1 x %\ld also be reg>d$ z giv+ s mu* ! m emphasis to t :i* is really tru/wor?y1 9 t x sets =? m frankly t :i* is d\btful4 ,hypo!tical & unsolv$ problems h be5 treat$1 s f> z practicable1 on ! multiple basis2 t is1 alt]native hypo!ses & alt]native int]pretations are frequ5tly pres5t$ :]e k does n w>rant positive conclusions4 ,9 _m cases ! topics discuss$ w be f\nd to be pres5t$ 9 ways diff]+ widely f ^? :i* h become famili>4 ,9 "s cases1 fundam5tally new conceptions ( famili> subjects are involv$2 9 o!rs1 topics n usually discuss$ 9 text-books are /at$ ) "s fullness2 & 9 /ill o!rs1 ! emphasis is laid on po9ts :i* h n commonly be5 br\ght into prom95ce4 ,:e!r ! au?ors h be5 wise 9 dep>t+ to ?is ext5t f beat5 pa?s1 ! us]s ( ! volumes mu/ decide4 ,! "w is int5d$ prim>ily = mature /ud5ts1 & is design$ to furni% ! basis = a ye>'s "w 9 ! lat] "p ( ! college c\rse4 ,by judici\s selection ( mat]ial to be pres5t$ & omitt$1 ! volumes w be f\nd useful = brief] c\rses1 & by ! use ( ! num]\s ref]5ces to ! full] discussions ( special treatises1 !y may be made ! basis = m ext5d$ c\rses ?an are commonly giv5 9 und]graduate "w4 ,! attempt has also be5 made to make ! volumes readable1 9 ! belief t _m p]sons n 9 colleges or univ]sities w be int]e/$ 9 foll[+ a connect$ acc\nt ( ! e>?'s hi/ory1 & ( ! means by :i* t hi/ory is record$ & read4 ,antec$5t elem5t>y c\rses 9 geology w n be necess>y to ! use ( ^! volumes1 ?\gh su* c\rses may be helpful4 ,! arrangem5t ( !mes adopt$ is su* z to br+ to ! =e processes ) :i* all /ud5ts are imm$iately 9 contact1 & :i* are available = /udy at all seats ( le>n+4 ,! common] geologic ag5ts1 su* z ! atmosph]e & runn+ wat]1 h be5 elaborat$ some:at m fully ?an is cu/om>y1 & ! common r ?an ! exceptional phases ( ! "w ( ^! ag5ts h be5 emphasiz$1 bo? because ( _! great] importance & _! univ]sal availability4 ,! text has be5 s %ap$ z to sugge/ field "w 9 connection ) ^! topics especially1 s9ce "w ( ?is sort is ev]y:]e possible4 ,aft] ! prelim9>y outl9e1 :i* is int5d$ to give "s idea ( ! scope ( ! sci5ce1 & ( its sali5t features1 & to %[ ! relations ( ! special subjects :i* foll[1 ! ord] ( treatm5t is su* z to pass f ! common] & m readily appreh5d$ portions ( ! subject to ^? :i* are less readily accessible & m obscure4 ,foll[+ ! same g5]al conception1 ! treatm5t ( ! topics is some:at grad$1 ! e>li] *apt]s be+ develop$ ) great] simplicity & fullness1 :ile ! lat] are some:at m cond5s$4 ,_m ackn[l$gm5ts are made 9 ! text & foot-notes1 b x is impossible to adequately ackn[l$ge all ! s\rces :i* h be5 drawn ^u1 s9ce ! :ole body ( lit]ature has be5 laid "u contribution4 ,! au?ors especially ackn[l$ge ! g5]\s assi/ance ( ,pr(essor ,j4 ,p4 ,idd+s 9 connection ) ! *apt] on ,! ,orig9 & ,desc5t ( ,rocks2 ( ,dr4 ,f4 ,r4 ,m\lton1 ,pr(essor ,c4 ,s4 ,sli*t]1 ,pr(essor ,l4 ,m4 ,hosk9s1 ,mr4 ,a4 ,c4 ,lunn1 & ,mr4 ,w4 ,h4 ,emmons 9 connection ) ma!matical problems2 ( ,pr(essor ,c4 ,r4 ,b>nes 9 connection ) ! geologic functions ( life2 & ( ,pr(essor ,julius ,/ieglitz 9 connection ) *emical subjects4 ,! illu/rations h be5 select$ f num]\s s\rces1 :i* are usually ackn[l$g$ 9 ! text4 ,especial ackn[l$gm5t is due to ! ,u4 ,s4 ,geological ,survey = ! use ( num]\s photographs & maps1 & to ,mr4 ,g4 ,a4 ,johnson1 :o has made _m ( ! draw+s reproduc$ 9 ,volume ,i4 ,! au?ors are "u ev5 l>g] obligations = assi/ance 9 ! prep>ation ( ,volume ,,ii1 = :i* ackn[l$gm5t w be made 9 ! prop] place4 ,univ]sity ( ,*icago1 ,janu>y1 #aijd4 ,,cont5ts4 ,,volume ,i4 ,,*apt] ,i4 ,,prelim9>y ,,outl9e4 ,subdivisions1 #a4 ,dom9ant processes1 #b4 ,,page ,a/ronomic ,geology #b ,! e>? z a planet1 #b4 ,its satellite1 #c4 ,dep5d5ce on ! sun1 #d4 ,meteorites1 #d4 ,geognosy #e ,i4 ,! ,atmosph]e #e ,mass & ext5t1 #f4 ,geologic activity1 #f4 ,a !rmal blanket1 #g4 ,,ii4 ,! ,hydrosph]e #g ,oceanic dim5sions1 #h4 ,geologic activity1 #h4 ,*ief horizons ( activity1 #i4 ,,iii4 ,! ,li?osph]e #i ,irregul>ities1 #aj4 ,epicont95tal seas1 #aa4 ,div]sities ( surface1 #ab4 ,! surface mantle ( ! li?osph]e1 #ab4 ,! cru/ ( ! li?osph]e1 #ac4 ,! int]ior1 #ad4 ,v>ieties ( rock 9 cru/1 #ad4 ,/ratifi$ rocks1 #ad4 ,con=mability1 #ae4 ,relative ages1 #ae4 ,! cry/all9e rocks1 #af4 ,f\r great s$im5t>y eras1 #ag4 ,! ,ar*ean complex1 #ah4 ,g5]al ,table ( ,geologic ,divisions #ai ,,*apt] ,,ii4 ,,! ,,atmosph]e ,,z ,a ,,geological ,,ag5t4 ,! ,atmosph]e z a ,direct ,ag5cy #ba ,i4 ,me*anical ,"w #ba ,transportation & deposition ( du/1 #bb4 ,transportation & deposition ( s&1 #be4 ,=mation ( dunes1 #bf4 ,%apes ( dunes1 #bf4 ,! topographic map1 #cj4 ,topography ( dune areas1 #cb4 ,migration ( dunes1 #cc4 ,di/ribution ( dunes1 #ce4 ,w9d ripples1 #cg4 ,abrasion by ! w9d1 #ch4 ,effects ( w9d on plants1 #dj4 ,indirect effects ( ! w9d1 #da4 ,,ii4 ,*emical ,"w #da ,precipitation f solution1 #da4 ,oxidation1 #db4 ,c>bonation1 #dc4 ,o!r *emical *anges1 #dc4 ,conditions favorable = *emical *anges1 #dc4 ,! ,atmosph]e z a ,condition+ ,ag5cy #dc ,i4 ,temp]ature ,effects #dd ,,ii4 ,evaporation & ,precipitation #ej ,,iii4 ,effects ( ,electricity4 #eb ,summ>y #ed ,,*apt] ,,iii4 ,,! ,,"w ,,( ,,runn+ ,,wat]4 ,ra9 & ,riv] ,erosion #eg ,subarial ,erosion )\t ,valleys #eh ,! ,developm5t ( ,valleys #fc ,by ! gr[? ( gullies1 #fc4 ,limits ( gr[?1 #fg4 ,! p]man5t /ream1 #gj4 ,o!r modes ( valley developm5t1 #gc4 ,/ructural valleys1 #gg4 ,! c\rses ( valleys1 #gg4 ,! developm5t ( tribut>ies1 #gh4 ,a ,cycle ( ,erosion4 ,its ,/ages #hj ,g5]al ,*>act]i/ics ( ,topography ,develop$ by ,riv] ,erosion #ib ,special ,features ,result+ f ,special ,conditions ( ,erosion #ib ,bad-l& topography1 #ic4 ,special =ms ( valleys2 canyons1 #id4 ,! ,/ruggle = ,exi/5ce ,among ,valleys & ,/reams #ajj ,piracy1 #ajc4 ,rate ( ,degradation #aje ,mat]ial 9 solution 9 riv] wat]1 #ajg4 ,economic ,consid]ations #ajh ,analysis ( ,erosion #aaj ,wea!r+4 #aaj ,transportation #aae ,transport+ p[] & velocity1 #aae4 ,h[ s$im5t is c>ri$1 #aaf4 ,corrasion #aai ,abrasion1 #aai4 ,solution1 #abb4 ,conditions ,affect+ ! ,rate ( ,erosion #abc ,! ,influ5ce ( ,declivity #abc ,! ,influ5ce ( ,rock #abd ,physical con/itution1 #abd4 ,*emical composition1 #abd4 ,/ructure1 #abe4 ,! ,influ5ce ( ,climate #abg ,effects ( ,unequal ,h>dness #acb ,rapids & falls1 #acb4 ,rock t]races1 #adj4 ,n>r[s1 #ada4 ,o!r effects on topography1 #adb4 ,adju/m5t ( /reams to rock /ructures1 #adf4 ,influ5ce ( ,jo9ts & ,folds #aej ,jo9ts1 #aej4 ,folds1 #aed4 ,effect ( ,*anges ( ,level #afa ,rise1 #afa4 ,s9k+1 #agj4 ,diff]5tial movem5t1 w>p+1 #aga4 ,! ,aggradational ,"w ( ,runn+ ,wat] #agg ,pr9ciples involv$1 #agg4 ,! ,deposits #aha ,types1 #aha4 ,alluvial fans & cones1 #aha4 ,ill-def9$ alluvium1 #ahc4 ,alluvial pla9s1 #ahd4 ,flood-pla9s due to alluviation1 #ahf4 ,flood-pla9s due to ob/ructions1 #ahh4 ,levees1 #ahh4 ,flood-pla9 me&]s1 cut-&-fill1 #aij4 ,sc\r-&-fill1 #aid4 ,mat]ials ( ! flood-pla91 #aif4 ,topography ( ! flood-pla91 #aif4 ,topographic adju/m5t ( tribut>ies1 #aig4 ,riv]-lakes1 #aih4 ,deltas1 #aih4 ,delta lakes1 #bjd4 ,/ream ,t]races #bjd ,due to inequalities ( h>dness1 #bjd4 ,normal flood-pla9 t]races1 #bje4 ,flood-pla9 t]races due to o!r causes1 #bjh4 ,discont9uity ( t]races1 #bji4 ,t]m9i ( t]races1 #baj4 ,,*apt] ,,iv4 ,,! ,,"w ,,( ,,gr\nd 7,,und]gr\nd7 ,,wat]4 ,conditions influ5c+ desc5t ( ra9-wat]1 #bac4 ,supply ( gr\nd-wat] n altoge!r dep5d5t on local ra9fall1 #bae4 ,gr\nd-wat] surface--wat] table1 #bae4 ,dep? to :i* gr\nd-wat] s9ks1 #baf4 ,movem5t ( gr\nd-wat]1 #bbj4 ,am\nt ( gr\nd-wat]1 #bba4 ,fate ( gr\nd-wat]1 #bba4 ,! ,"w ( ,gr\nd-wat] #bbb ,*emical ,"w #bbb ,quantitative importance ( solution1 #bbc4 ,deposition ( m9]al matt] f solution1 #bbe4 ,me*anical ,"w #bbf ,results ( ! ,"w ( ,gr\nd-wat] #bbf ,wea!r+1 #bbf4 ,cav]ns1 #bbg4 ,creep1 slumps1 & l&slides1 #bca4 ,summ>y #bcb ,spr+s & ,fl[+ ,wells #bcd ,m9]al matt] 9 solution1 #bce4 ,geys]s1 #bcf4 ,artesian wells1 #bdb4 ,,*apt] ,v4 ,,! ,,"w ,,( ,,sn[ ,,& ,,ice4 ,sn[- & ,ice-fields #bdd ,! passage ( sn[ into nv & ice1 #bdf4 ,/ructure ( ! ice1 #bdg4 ,texture1 #bdg4 ,inauguration ( movem5t1 #bdh4 ,types ( ,glaci]s #bea ,! ,g5]al ,ph5om5a ( ,glaci]s #bef ,dim5sions1 #bef4 ,limits1 #beh4 ,movem5t1 #bei4 ,conditions affect+ rate ( movem5t1 #bfa4 ,lik5esses & unlik5esses ( glaci]s & riv]s1 #bfb4 ,surface ,features #bff ,topography1 #bff4 ,surface mora9es1 #bff4 ,relief due to surface dbris1 #bfh4 ,du/-wells1 #bfi4 ,dbris bel[ ! surface1 #bgb4 ,temp]ature1 ,wa/e1 & ,dra9age #bgc ,! w9t] wave1 #bgd4 ,! summ] wave1 #bgf4 ,! temp]ature ( ! bottom1 #bgf4 ,temp]ature ( ! int]ior ( ! ice1 #bgg4 ,compression & friction z causes ( heat1 #bgh4 ,summ>y1 #bgi4 ,movem5t "u l[ temp]ature1 #bgi4 ,evaporation1 #bgi4 ,dra9age1 #bhj4 ,! ,"w ( ,glaci]s #bha ,erosion & ,transportation #bha ,gett+ load1 #bhb4 ,conditions influ5c+ rate ( erosion1 #bhc4 ,summ>y1 #bhf4 ,v>i$ nature ( glacial dbris1 #bhf4 ,! topographic effects ( glacial erosion1 #bhg4 ,fiords1 #bij4 ,! positions 9 :i* dbris is c>ri$1 #bij4 ,transf]s ( load1 #bib4 ,we> ( drift 9 transit1 #bih4 ,deposition ( ! ,drift #bih ,b5ea? ! body ( ! ice1 #bih4 ,at ends & edges ( glaci]s1 #bii4 ,types ( ,mora9es #cja ,! t]m9al mora9e1 #cja4 ,! gr\nd mora9e1 #cja4 ,! lat]al mora9es1 #cjb4 ,di/9ctive nature ( glacial deposits1 #cjd4 ,glaciat$ rock surfaces1 #cjd4 ,glacio-,fluvial ,"w #cje ,iceb]gs #cjg ,! ,intimate ,/ructure & ! ,movem5t ( ,glaci]s #cjh ,! gr[? & con/itution ( a glaci]1 #cjh4 ,! arrangem5t ( ! cry/al axes1 #cab4 ,! ,probable ,fundam5tal ,elem5t 9 ,glacial ,motion #cac ,melt+ & freez+1 #cac4 ,accumulat$ motion 9 ! t]m9al "p ( a glaci]1 #caf4 ,auxili>y ,elem5ts #cag ,%e>+1 #cag4 ,high temp]ature & wat]1 #cah4 ,applications1 #cai4 ,corroborative ,ph5om5a #cbj ,o!r ,views ( ,glaci] ,motion #cba ,,*apt] ,,vi4 ,,! ,,"w ,,( ,,! ,,ocean4 ,volume & composition1 #cbd4 ,topography ( b$1 #cbf4 ,di/ribution ( m>9e life1 #cbh4 ,processes 9 ,op]ation 9 ! ,sea #cbi ,dia/rophism1 #cbi4 ,vulcanism1 #ccb4 ,gradation1 #ccc4 ,movem5ts ( ! ,sea-wat] #ccd ,diff]5ces 9 d5sity & _! results1 #cce4 ,diff]5ces 9 level & _! results4 #cce4 ,movem5ts g5]at$ by w9ds1 #ccf4 ,movem5ts g5]at$ by attraction1 #cbb4 ,ap]iodic movem5ts1 #cch4 ,summ>y1 #cci4 ,waves #cci ,wave-motion1 #cci4 ,"w ( ! ,waves #cdb ,erosion #cdb ,by waves & und]t[1 #cdb4 ,topographic ,features ,develop$ by ,wave ,erosion #cdi ,! sea-cliff1 #cdi4 ,*imney rocks1 etc41 #cej4 ,sea caves1 #cej4 ,! wave-cut t]race1 #cea4 ,wave erosion & horizontal configuration1 #cec4 ,transportation by ,waves #ced ,deposition by ,waves1 ,und]t[1 & ,%ore ,curr5ts #cee ,! bea*1 #cee4 ,! b>ri]1 #cef4 ,! spit1 ! b>1 & ! loop1 #ceg4 ,wave-built t]races1 #cfc4 ,effect ( ,%ore ,deposition on ,coa/al ,configuration #cfc ,summ>y ( ,coa/al ,irregul>ities #cfd ,! ,"w ( ,ocean-curr5ts #cff ,deposits ( ! ,ocean-b$ #cfh ,%all[-wat] ,deposits #cfi ,littoral deposits1 #cfi4 ,non-littoral1 me*anical deposits 9 %all[ wat]1 #cfi4 ,*>act]i/ics ( %all[-wat] deposits1 #cgc4 ,topography ( %all[-wat] deposits1 #cgd4 ,*emical & organic deposits1 #cge4 ,lime/one1 #cgh4 ,deep-sea ,deposits #cgh ,contra/$ ) %all[-wat] deposits1 #cgh4 ,s\rces1 #chj4 ,me*anical inorganic deposits1 #chj4 ,organic con/itu5ts ( pelagic deposits1 #chb4 ,*emical deposits1 #chc4 ,lakes #chf ,*anges tak+ place 9 lakes1 #chg4 ,lacu/r9e deposits1 #chh4 ,ext9ct lakes1 #chh4 ,lake ice1 #chi4 ,sal9e lakes1 #cia4 ,indirect effects ( lakes1 #cib4 ,composition ( lake wat]s1 #cib4 ,,*apt] ,,vii4 ,,! ,,orig9 ,,& ,,desc5t ,,( ,,rocks4 ,composition ( ,igne\s ,rocks #cie ,lead+ elem5ts1 #cif4 ,union ( elem5ts1 #cig4 ,=mation ( m9]als1 #cig4 ,s\rces ( complexity1 #cih4 ,! lead+ m9]als ( igne\s rocks1 #cii4 ,! feldspa?ic m9]als1 #djj4 ,! f]romagnesian m9]als1 #djj4 ,summ>y ( sali5t facts1 #dja4 ,! ,nature ( ,molt5 ,magmas #dja ,"t requir$ 9 cry/allization1 #djb4 ,successive /ages ( cry/allization1 #djc4 ,! ,fragm5tal ,products ( ,sudd5 ,cool+ #djd ,pyrocla/ic rocks1 #djd4 ,! ,glassy ,rocks #djf ,! solid glasses4 #djf4 ,! fir/ /ages ( cry/allization1 #djg4 ,! obsidians1 #djg4 ,special ,/ructures #daj ,fl[ /ructure1 #daj4 ,amygdaloids1 #daa4 ,! ,porphyritic ,rocks #daa ,! ,phan]ocry/all9e ,rocks #dab ,! phan]ites1 #dab4 ,! granites1 #dac4 ,! sy5ites1 #dae4 ,! diorites1 #daf4 ,! gabbros1 #daf4 ,! p]idotites1 #daf4 ,! basalts1 #dag4 ,! dol]ites1 #dag4 ,g5]al names1 #dah4 ,d]ivation ( ,second>y ,rocks #dbj ,regoli?1 #dbb4 ,disrupt$ products3 arkose & wacke1 #dbb4 ,dis9tegrat$ products1 #dbb4 ,classes ( ,s$im5t>y ,rocks #dbb ,%ales1 s&/ones1 & conglom]ates1 #dbb4 ,lime/ones & dolomites1 #dbd4 ,precipitates1 #dbd4 ,iron-ore b$s1 #dbe4 ,silici\s deposits1 #dbe4 ,organic rocks1 #dbf4 ,int]nal ,alt]ations ( ,rocks #dbf ,oxidation & deoxidation1 #dbg4 ,solution & deposition1 #dbg4 ,hydration & dehydration1 #dbh4 ,c>bonation & dec>bonation1 #dbi4 ,molecul> re>rangem5ts1 #dca4 ,! ,sali5t ,features ( ,rock ,desc5t #dca ,! ,reasc5sional ,process #dcb ,induration "u ord9>y pressures & temp]atures1 #dcb4 ,cavity fill+1 #dcf4 ,fissure fill+2 ve9s1 #dcg4 ,solution z well z deposition1 #dcg4 ,concretions1 #dch4 ,replacem5ts & pseudomorphs1 #dci4 ,incipi5t cry/allization1 #dci4 ,recon/ruction "u ,exceptional ,conditions #ddj ,slaty /ructure1 #dda4 ,foliation1 s*i/osity1 #ddc4 ,metamorphism by heat1 #ddf4 ,metamorphism by heat & lat]al pressure1 #ddh4 ,deep-seat$ metamorphism1 #ddi4 ,completion ( ! rock cycle1 #ddi4 ,v>i\s ,classifications & ,nom5clatures #ddi ,new ,sy/em ( ,classification & ,nom5clature #dea ,! ,propos$ ,field ,sy/em #dea ,! phan]ites1 #dea4 ,! aphanites1 #deb4 ,! ,propos$ ,quantitative ,sy/em #ded ,ref]5ce ,li/ ( ! ,m ,common ,m9]als #dfj ,ref]5ce ,li/ ( ! ,m ,common ,rocks #dfg ,ore ,deposits #dgd ,conc5tration1 #dgd4 ,exceptional & d\btful cases1 #dgd4 ,orig9al di/ribution1 #dge4 ,magmatic segregation1 #dge4 ,m>9e segregation & disp]sion1 #dgf4 ,orig9 ( ore regions1 #dgg4 ,surface residual conc5tration1 #dgh4 ,purification & conc5tration1 #dgh4 ,conc5tration by solution & reprecipitation1 #dgi4 ,location ( greate/ solv5t action1 #dhj4 ,%ort-c\rse action1 #dha4 ,long-c\rse action1 #dha4 ,summ>y1 #dhc4 ,! influ5ce ( contacts1 #dhd4 ,! effect ( igne\s intrusions1 #dhd4 ,! influ5ce ( rock walls1 #dhd4 ,,*apt] ,,viii4 ,,/ructural 7,,geotectonic7 ,,geology4 ,! /ructural phases :i* rocks assume1 #dhf4 ,/ructural ,features ( ,s$im5t>y ,rocks #dhf ,/ratification1 #dhf4 ,lat]al graduation1 #dhh4 ,special m>k+s1 #dhi4 ,concretion>y /ructure1 #dij4 ,secretions1 #dig4 ,/ructural ,features ( ,igne\s ,rocks #dih ,/ructural ,features ,aris+ ,f ,di/urbance #ejj ,incl9ation & fold+ ( /rata1 #ejj4 ,jo9ts1 #eaj4 ,s&/one dikes1 #ead4 ,faults1 #ead4 ,! significance ( faults1 #eba4 ,effect ( fault+ on outcrops1 #ebb4 ,,*apt] ,,ix4 ,,! ,,movem5ts ,,& ,,de=mations ,,( ,,! ,,e>?',s ,,body 7,,dia/rophism74 ,m9ute & ,rapid ,movem5ts #ebf ,e>?quakes #ebg ,po9ts ( orig91 foci1 #ebg4 ,! amplitude ( ! vibrations1 #ebi4 ,de/ructive effects1 #ecj4 ,direction ( ?r[1 #eca4 ,rate ( propagation1 #ecb4 ,sequ5ces ( vibrations1 #ecc4 ,gase\s emanations1 #ecc4 ,di/ribution ( e>?quakes1 #ecc4 ,! ,geologic ,effects ( ,e>?quakes #ecd ,fractur+ ( rock1 #ecd4 ,*anges ( surface1 #ecd4 ,effects on dra9age1 #ece4 ,effects on /&+ wat]1 #ece4 ,*anges ( level1 #ecf4 ,sl[ ,massive ,movem5ts #ecg ,pres5t movem5ts1 #ech4 ,fundam5tal conceptions1 #eci4 ,ne>ly ,con/ant ,small ,movem5ts #edj ,reciprocal features1 #eda4 ,! ,great ,p]iodic ,movem5ts #edb ,m\nta9-=m+ movem5ts1 #edb4 ,di/ribution ( fold$ ranges1 #edc4 ,plateau-=m+ movem5ts1 #edc4 ,cont95t-=m+ movem5ts1 #edd4 ,relations ( ^! movem5ts 9 "t1 #ede4 ,relations ( v]tical to horizontal movem5ts1 #ede4 ,! squeez$ segm5ts1 #edf4 ,! depress$ or ma/] segm5ts1 #edf4 ,! diff]5tial ext5t ( cru/al movem5ts1 #edh4 ,! ,causes ( ,movem5t #eea ,g5]al ,consid]ations #eea #a4 ,! c5tripetal ag5cies #eeb ,gravity1 #eeb4 ,molecul> & sub-molecul> attractions1 #eed4 ,cohesion & cry/allization1 #eed4 ,diffusion1 #eee4 ,*emical comb9ation1 #eef4 ,sub-atomic =ces #eef4 #b4 ,! resi/+ ag5cies #eeg ,heat1 #eeg4 ,all resi/ance p]haps due to motion1 #eeh4 ,alt]native ,views ( ,orig9al ,heat ,di/ribution #eei ,!rmal di/ribution on ! convection hypo!sis1 #eei4 ,level ( no /ress1 #efa4 ,!rmal di/ribution on ! hypo!sis ( c5tral solidification1 #efb4 ,!rmal di/ribution "u ! accretion hypo!sis1 #efd4 ,comput$ ,pressures1 ,d5sities1 & ,temp]atures )9 ! ,e>? ,bas$ on ,laplace's ,law #efd ,recomb9ation ( mat]ial1 #efh4 ,comp>ison ( ! hypo!ses1 #efh4 ,obs]v$ ,temp]atures 9 ,excavations #efi ,explanations ( v>y+ increm5t1 #egj4 ,! p]meation & circulation ( wat]1 #egj4 ,*emical action1 #egj4 ,diff]5ces 9 ! conductivity ( rock1 #ega4 ,compression1 #ega4 ,gradi5ts project$1 #ega4 ,! am\nt ( loss ( heat1 #egb4 ,! am\nt ( %r9kage f loss ( heat1 #egb4 ,o!r ,s\rces ( ,de=mation #egd ,transf] ( int]nal heat1 #egd4 ,d5s] aggregation ( matt]1 #egd4 ,extravasation ( lavas1 #egd4 ,*ange 9 ! rate ( rotation1 #ege4 ,di/ribution ( rigidity1 #egh4 ,sph]icity z a ,factor 9 ,de=mation #ehj ,! influ5ce ( ! dom$ =m ( ! surface1 #eha4 ,!oretical /r5g? ( domes ( e>?-dim5sions1 #eha4 ,/ress-accumulation indep5d5t ( sph]icity1 #ehc4 ,! actual configuration ( ! surface1 #ehd4 ,concave tracts1 #ehd4 ,g5]al conclusion1 #ehh4 ,,*apt] ,x4 ,,! ,,extrusive ,,processes4 ,outw>d movem5ts1 #eij4 ,vulcanism #eij ,phases ( vulcanism1 #eia4 #a4 ,intrusions #eia ,! heat+ action1 #eib4 #b4 ,extrusions #eib ,fissure eruptions1 #eic4 ,volcanic eruptions1 #eid4 ,int]m$iate ph5om5a1 #eif4 ,lun> crat]s1 #eih4 ,volcanoes #eii ,numb] (1 #eii4 ,di/ribution ( ,volcanoes #eii ,9 "t1 #eii4 ,relative to l& & sea1 #eii4 ,relative to cru/al de=mations1 #fja4 ,9 latitude1 #fjc4 ,9 curv$ l9es1 #fjc4 ,relations ( ,volcanoes #fjd ,relations to ris+ & s9k+ surfaces1 #fjd4 ,relations to "o ano!r1 #fje4 ,unimportant co9cid5ces1 #fjf4 ,p]iodicity1 #fjg4 ,=mation ( ,cones #fjh ,lava-cones1 #fjh4 ,c9d]-cones1 #fjh4 ,subord9ate cones1 #faj4 ,composite cones1 #faj4 ,extra-cone di/ribution1 #faj4 ,lavas #fab ,_! nature1 #fab4 ,consangu9ity & succession ( lavas1 #fad4 ,temp]ature ( lavas1 #fae4 ,dep? ( s\rce1 #faf4 ,volcanic ,gases #fag ,diff]5ces 9 gas action1 #fag4 ,spasmodic action1 #fah4 ,k9ds ( gases1 #fah4 ,residual gases 9 volcanic rock1 #fai4 ,! s\rce ( ! gases1 #fba4 ,! ,cause ( ,vulcanism #fbc ,i4 ,on ! ,assumption t ! ,lavas are ,orig9al #fbc ,lava outfl[s f a molt5 int]ior1 #fbd4 ,lavas assign$ to molt5 res]voirs1 #fbd4 ,,ii4 ,on ! ,assumption t ! ,lavas are ,second>y #fbe ,lavas assign$ to ! reaction ( wat] & air p5etrat+ to hot rocks1 #fbe4 ,lavas assign$ to relief ( pressure1 #fbg4 ,lavas assign$ to melt+ by cru%+1 #fbh4 ,lavas assign$ to melt+ by depression1 #fbi4 ,vulcanism assign$ to ! outfl[ ( deep-seat$ heat1 #fbi4 ,modes ( ,rea*+ ! ,surface #fca ,additional ,consid]ations ,relative to ! ,gases #fcc ,!rmal ,consid]ations #fce ,,*apt] ,,xi4 ,,! ,,geologic ,,functions ,,( ,,life4 ,i4 ,! ,di/9ctive ,features ( ,organic ,processes #fch ,! ,*emical ,"w ( ,life #fch ,life mat]ial *iefly atmosph]ic1 #fch4 ,! non-atmosph]ic factors1 #fci4 7#a7 ,*anges 9 ! composition ( ! atmosph]e #fci ,! consumption & re/oration ( c>bon dioxide1 #fdj4 ,! freez+ & consumption ( oxyg51 #fdj4 ,! organic residue1 #fdj4 ,! mean+ ( ! organic residue1 #fda4 ,! m in]t factor1 #fdb4 ,probable fluctuations ( atmosph]ic composition1 #fdb4 ,! climatic effects ( organic action1 #fdc4 7#b7 ,aid & h9drance to inorganic action #fdd ,! promotion ( dis9tegration1 #fdd4 ,protection aga9/ erosion1 #fdd4 ,! influ5ce ( l& vegetation on ! "* ( ! s$im5ts1 #fde4 7#c7 ,di/9ctive deposits #fdf ,organic rocks1 #fdf4 ,inorganic rocks due to life1 #fdf4 ,fossils #fdf ,! g5]al ord] ( life succession det]m9$ by /ratigraphy1 #fdg4 ,fossils z means ( correlation1 #fdg4 ,special ,modes ( ,aggregation & ( ,movem5t #fdh ,! ,m5tal ,elem5t #fdi 7#a7 ,! mat]ial effects ( ! m5tal elem5t1 #fdi4 ,human modification ( ! animal & vegetal k+doms1 #fej4 7#b7 ,! psy*ological factors z su*1 #fea4 ,,ii4 ,special ,contributions ( ! ,organic ,k+doms #feb ,contributions ( ! ,plant ,k+dom #feb ,ref]5ce table ( ! pr9cipal gr\ps ( plants1 #fec4 ,! contribution ( ! ,?allophytes1 #fec4 ,! contribution ( ! ,bryophytes1 #fef4 ,! contribution ( ! ,pt]idophytes1 #feg4 ,! contribution ( ! ,sp]matophytes1 #feg4 ,plant life t]re/rial r ?an m>9e1 #feh4 ,contributions ( ! ,animal ,k+dom #feh ,ref]5ce table ( ! pr9cipal gr\ps ( animals1 #fei4 ,! contribution ( ! ,protozoa1 #ffj4 ,! contribution ( ! ,cl5t]ata1 #ffa4 ,! contribution ( ! ,e*9od]mata1 #ffa4 ,! contribution ( ! ,v]mes1 #ffb4 ,! contribution ( ! ,molluscoidea1 #ffb4 ,! contribution ( ! ,mollusca1 #ffb4 ,! contribution ( ! ,ar?ropoda1 #ffb4 ,! contribution ( ! ,v]tebrata1 #ffc4 ,,iii4 ,! ,associations & ,ecological ,relations ( ,life #ffc ,! ,basis ( ,floras & ,faunas #ffc ,assemblages ,influ5c$ by ! ,mutual ,relations ( ,organisms #ffd ,food relations1 #ffd4 ,adaptive relations1 #ffe4 ,competitive relations1 #ffe4 ,(f5sive & def5sive relations1 #ffe4 ,impli$ =ms ( life1 #fff4 ,assemblages ,influ5c$ by ,environm5t #fff ,plant societies1 #ffg4 ,! ,influ5ce ( ,geographic ,conditions on ! ,evolution ( ,floras & ,faunas #ffh ,! developm5t ( prov9cial & cosmopolitan faunas1 #ffh4 ,re/rictive & expansional evolution1 #fgb4 ,,plates4 plate face page ,i4 ,ba?ymetrical ,*>t ( ! ,oceans #aj ,,ii4 ,fig4 #a4 ,new ,j]sey4 ,fig4 #b4 ,kansas4 ,fig4 #c4 ,indiana4 ,fig4 #d4 ,nebraska #ci ,,iii4 ,fig4 #a4 ,kansas4 ,fig4 #b4 ,nevada #gb ,,iv4 ,fig4 #a4 ,ill9ois4 ,fig4 #b4 ,nor? ,dakota #gc ,v4 ,fig4 #a4 ,k5tucky4 ,fig4 #b4 ,virg9ia #he ,,vi4 ,p>ts ( ,los ,angeles & ,san ,b]n>d9o ,c\nties1 ,cali=nia4 #hg ,,vii4 ,kansas #ij ,,viii4 ,ab\t #af ,miles ,s\?we/ ( ,/4 ,l\is1 ,mo4 #ia ,,ix4 ,niag>a ,falls #ajj ,x4 ,fig4 #a4 ,yell[/one ,p>k4 ,fig4 #b4 ,arizona #aja ,,xi4 ,"p ( ! ,catskills1 ,n4 ,y4 #ajf ,,xii4 ,fig4 #a4 ,new ,mexico4 ,fig4 #b4 ,virg9ia1 ,we/ ,virg9ia1 & ,m>yl& #ajg ,,xiii4 ,fig4 #a4 ,colorado4 ,fig4 #b4 ,kansas #afb ,,xiv4 ,fig4 #a4 ,p5nsylvania4 ,fig4 #b4 ,cali=nia #afc ,,xv4 ,ne> ,hahnville1 ,l\isiana #ahh ,,xvi4 ,miss\ri #ahi ,,xvii4 ,fig4 #a4 ,hunt]don ,c\nty1 ,n4 ,j4 ,fig4 #b4 ,ne> ,pikeville1 ,t5n4 #bcb ,,xviii4 ,fig4 #a4 ,wa%+ton4 ,fig4 #b4 ,cali=nia #bcc ,,xix4 ,"p ( ! ,big ,horn ,range1 ,wyom+ #bhf ,,xx4 ,section ( ! ,cali=nia ,coa/ ne> ,san ,mateo1 ,cal4 #bhg ,,xxi4 ,new ,j]sey #cef ,,xxii4 ,fig4 #a4 ,portion ( ,s\? ,coa/ ( ,m>?a's ,v9ey>d1 ,mass4 ,fig4 #b4 ,portion ( ! ,cali=nia ,coa/ ne> ,tamalpais #ceg ,,xxiii4 ,fig4 #a4 ,massa*usetts4 ,fig4 #b4 ,ma9e #cfd ,,xxiv4 ,portion ( ! ,coa/ ( ,ma9e #cfe ,,tables4 ,analyses ( ,am]ican ,riv]-wat]s #ajf ,analyses ( ,am]ican ,spr+-wat]s #bcf ,analyses ( ! ,wat]s ( ,inclos$ ,lakes #cib ,,geology ,,*apt] ,i4 ,,prelim9>y ,,outl9e4 ,geology treats ( ! /ructure ( ! e>?1 ( ! v>i\s /ages ?r\gh :i* x has pass$1 & ( ! liv+ be+s t h dwelt ^u x1 toge!r ) ! ag5cies & processes involv$ 9 ! *anges x has und]gone4 ,geology is ess5tially a hi/ory ( ! e>? & its inhabitants4 ,x is "o ( ! broade/ ( ! sci5ces1 & br+s "u consid]ation c]ta9 phases ( ne>ly all ! o!r sci5ces1 p>ticul>ly ^? ( a/ronomy1 physics1 *emi/ry1 zoology1 & botany4 ,x also embraces ! e>li] expressions ( m5tal developm5t & ( life-relation%ips1 *iefly z f\nd 9 ! l[] animals4 ,subdivisions4--,naturally s broad a sci5ce has _m special aspects :i* con/itute subdivisions1 9 a s5se1 ?\gh !y are r dom9ant phases ?an indep5d5t sections4 ,t phase :i* treats ( ! out] relations ( ! e>? is ,cosmic or ,a/ronomic geology2 t :i* treats ( ! con/itu5t p>ts ( ! e>? & its mat]ial is ,geognosy1 ( :i* ! mo/ important bran* is ,petrology1 ! sci5ce ( rocks4 ,t bran* :i* inve/igates ! /ructural arrangem5t ( ! mat]ial1 or 8! ar*itecture ( ! e>?10 is ,geotectonic1 or ,/ructural geology2 :ile t :i* deals ) ! surface *anges & topographic =ms1 t is1 ) ! face ( ! e>?1 is ,physiographic geology4 ,! /udy ( ! fossils t h be5 pres]v$ 9 ! rocks1 & ( ! faunas & floras t ^! imply1 con/itutes ,paleontologic geology1 or ,paleontology4 ,! treatm5t ( ! succession ( ev5ts =ms ,hi/orical geology4 ,?is is *iefly work$ out by ! succession ( b$s laid d[n 9 ! progress ( ! ages1 :i* con/itutes ,/ratigraphic geology4 ,! treatm5t ( causes1 ag5cies1 & processes is ! function ( ,dynamic or ,philosophic geology4 ,besides ^! !re are special applications :i* give occasion = o!r t]ms1 z ,economic geology1 :i* is conc]n$ ) ! indu/rial applications ( geologic k2 ,m9+ geology1 :i* is a sub-section ( economic geology1 relat+ to ! application ( geologic facts & pr9ciples to m9+ op]ations2 ,atmosph]ic geology1 ,glacial geology1 & o!rs t def9e !mselves1 & are = ! great] "p b limit$ aspects ( ! broad sci5ce4 ,dom9ant processes4--,?ree sets ( processes1 n[ 9 op]ation on ! surface ( ! li?osph]e1 h giv5 rise to mo/ ( ! details ( its configuration1 & ev5 _m ( its l>g] features4 ,^! processes h be5 designat$ dia/rophism1 vulcanism1 & gradation4 ,dia/rophism includes all cru/al movem5ts1 :e!r sl[ or rapid1 g5tle or viol5t1 slight or ext5sive4 ,_m p>ts ( ! l&1 especially along coa/s1 are kn[n to be sl[ly s9k+ relative to ! sea-level1 :ile o!r p>ts are kn[n to be ris+4 ,! fact t rocks orig9ally =m$ b5ea? ! sea n[ exi/ at great elevations1 & ! fur!r fact t areas :i* 7 once l& are n[ b5ea? ! sea1 are suffici5t evid5ce t simil> *anges h tak5 place 9 ! pa/4 ,vulcanism includes all processes connect$ ) ! extrusion ( lava & o!r volcanic products1 & ) ! rise ( lava f l[] to high] levels1 ev5 if n extrud$4 ,vulcanism & dia/rophism may be closely associat$1 = local movem5ts at lea/ are (t5 associat$ ) volcanic eruptions1 & m consid]able movem5ts may be connect$ ) ! movem5ts ( subsurface lavas1 ev5 :5 ! connection is n demon/rable4 ,gradation includes all ^? processes :i* t5d to br+ ! surface ( ! li?osph]e to a common level4 ,gradational processes belong to two categories--^? :i* level d[n1 degradation1 & ^? :i* level up1 aggradation4 ,! transportation ( mat]ial f ! l&1 :e!r by ra91 riv]s1 glaci]s1 waves1 or w9ds1 is degradation & ! deposition ( mat]ial1 :e!r on ! l& or 9 ! sea1 is aggradation4 ,degradation affects prim>ily ! protub]ances ( ! li?osph]e1 :ile aggradation affects prim>ily its depressions4 ,a/ronomic ,geology4 ,! e>? z a planet4--,?\gh supremely important to u1 ! e>? is b "o ( ! m9or planets att5dant ^u ! sun1 & is 9 no v special way di/+ui%$ z a planet>y body4 ,( ! eight planets1 f\r1 ,jupit]1 ,saturn1 ,uranus1 & ,neptune1 are mu* l>g] ?an ! e>?1 :ile ?ree1 ,m>s1 ,v5us1 & ,m]cury1 are small]4 ,!re are a ho/ ( a/]oids1 b all toge!r !y d n equal ! mass ( ! smalle/ planet4 ,! av]age mass ( ! eight planets is m ?an fifty times t ( ! e>?1 :ile ! l>ge/1 ,jupit]1 is m ?an ?ree hundr$ times z massive z ! e>?4 ,! e>?'s position 9 ! gr\p is 9 no s5se di/+ui%$4 ,x is nei!r ! out] nor ! inn]1 nor ev5 ! middle planet4 ,ev5 9 ! m9or gr\p to :i* x belongs1 x is nei!r ! out]mo/ nor ! inn]mo/ memb]1 ?\gh 9 ?is gr\p x is ! l>ge/4 ,its av]age di/ance f ! sun is ab\t #ib4i million miles1 & ?is fixes its revolution at #cfe days1 = its p]iod ( revolution is directly dep5d5t on its di/ance f ! sun1 & is necess>ily long] ?an ! revolutions ( ! inn] planets & %ort] ?an ^? ( ! out] planets4 ,its rotation 9 tw5ty-f\r h\rs is n f> diff]5t f t ( its neighbor ,m>s1 b is mu* sl[] ?an ! m di/ant & l>g] planets1 ,jupit] & ,saturn1 :i* rotate 9 ab\t t5 h\rs4 ,comp>ison _c be made ) ! inn]mo/ & out]mo/ planets1 because _! rotations are n yet satisfactorily det]m9$4 ,! plane ( ! e>?'s revolution lies ne> ! common plane ( ! :ole sy/em1 b ?is is n peculi>1 z all ( ! planets revolve 9 ne>ly ! same plane4 ,only a few ( ! small a/]oids dep>t notably f ?is common plane4 ,?is has an important be>+ on !ories ( ! orig9 ( ! sy/em1 s9ce ?is close co9cid5ce ( ! planes ( ! orbits is n consi/5t ) any haphaz>d aggregation ( ! mat]ial4 ,( simil> importance is ! fact t all ( ! planets revolve 9 ! same direction & 9 ellipses t d n dep>t widely f circles4 ,! ecc5tricity ( ! e>?'s orbit is only ab\t 4 ,?is ecc5tricity v>ies some:at1 due to ! di/urb+ influ5ces ( ! o!r planets1 & ?is v>iation has be5 reg>d$ by "s geologi/s z an influ5tial cause ( climatic *anges1 b its adequacy to produce great effects has be5 d\bt$ by o!rs4 ,! incl9ation ( ! e>?'s axis1 n[ ab\t #bc1 holds an int]m$iate position1 "s ( ! planets hav+ axes m incl9$1 z ,saturn1 #bf1 & o!rs less incl9$1 z ,jupit]1 #c4 ,! incl9ation ( ! axis is subject to trivial v>iations at pres5t1 & 9 ! long p]iods ( ! pa/ has possibly *ang$ m notably4 ,?is possible *ange has also be5 ?\ght to be a cause ( climatic v>iation1 b its effici5cy has n be5 demon/rat$4 ,its satellite4--,! e>? is peculi> 9 hav+ "o unusually l>ge satellite1 :i* has a mass ( its own4 ,! great planets h sev]al satellites ^: comb9$ mass exce$s t ( ! moon1 & p]haps 9 "s few cases ! individual satellites may be l>g] ?an ! moon1 b !y d n su/a9 s l>ge a ratio to _! planets1 = ,titan1 probably ! l>ge/1 is only ( ! mass ( ,saturn4 ,!re is little d\bt t ! moon has play$ an important "p 9 ! hi/ory ( ! e>?4 ,x is ! *ief ag5cy 9 develop+ oceanic tides1 & x possibly also develops a body tide 9 ! e>? itself4 ,^! tides act z a brake on ! rotation ( ! e>? & t5d to r$uce its rate1 & !reby to l5g!n ! day4 ,:ile ?is may h be5 c\nt]act$ 9 "s measure by ! %r9kage ( ! e>?1 :i* t5ds to increase its rate ( rotation1 x has be5 held by em95t physici/s & geologi/s t ! rotation ( ! e>? has be5 greatly less5$ dur+ its hi/ory1 & t a long tra9 ( important consequ5ces has result$4 ,if ! contraction ( ! e>? has be5 suffici5t to (fset ?is less5+1 ! tidal brake mu/ be cr$it$ ) ! prev5tion ( ! excessive spe$ ( rotation :i* w\ld o!rwise h be5 develop$4 ,! tides are effici5t ag5cies 9 ! %ore we> ( ! oceans1 & 9 ! di/ribution ( m>9e s$im5ts1 & ^!1 x w be se5 lat]1 are important elem5ts 9 ! =mation ( /rata4 ,dep5d5ce on ! sun4--,by f> ! mo/ important ext]nal relation ( ! e>?1 h[ev]1 is its dep5d5ce on ! sun4 ,! e>? is a m]e satellite ( ! sun1 less ?an ( its mass1 & h5ce "u its full gravitative control4 ,! e>? is dep5d5t on ! sun = ne>ly all its heat & light1 &1 ?r\gh ^!1 = ne>ly all ( ! activities t h giv5 "* to its hi/ory4 ,x is too mu* to say t all activities on ! surface ( ! e>? are solely dep5d5t on ^? ( ! sun1 = a c]ta9 measure ( heat & light & o!r en]gy is d]iv$ f o!r bodies1 & a c]ta9 n inconsid]able s\rce ( en]gy is f\nd 9 ! int]ior ( ! e>? itself2 yet all ( ^! are s f> subord9ate to t great flood ( en]gy :i* comes f ! sun t !y are q inconsequ5tial4 ,! hi/ory ( ! e>? 9 ! pa/ has be5 intimately dep5d5t ^u t ( ! sun1 & its future is lock$ up ) ! de/9y ( t great lum9>y4 ,geology 9 its broade/ phases c !re=e sc>cely be sep>at$ f ! /udy ( ! sun1 b ?is falls )9 ! function ( ! a/ronom] r ?an ! geologi/4 ,meteorites4--,!re are a multitude ( small bodies pass+ ?r\gh space 9 v>y+ directions & ) v>y+ velocities & occasionally enc\nt]+ ! e>?1 to :i* !y add _! sub/ance4 ,"s ( ^! meteorites revolve ab\t ! sun mu* z if !y 7 m9ute planets1 b "s ( !m come f su* directions & ) su* velocities z to %[ t !y d n belong to ! sol> family4 ,"s consi/ almo/ :olly ( metal1 *iefly iron alloy$ ) a small p]c5t4 ( nickel 7holosid]ites72 "s consi/ ( metal & rock intimately mix$ 7syssid]ites & sporadosid]ites72 & "s consi/ :olly ( rock 7asid]ites74 ,! rock is usually compos$ ( ! heavi] basic m9]als1 ?\gh "s meteorites consi/ l>gely ( c>bonace\s mat]ial4 ,besides meteorites1 !re is little d\bt t w&]+ gase\s p>ticles /rike ! e>?1 b ?is is beyond ! rea* ( pres5t demon/ration4 ,! am\nt ( sub/ance add$ to ! e>? by ^! meteorites & gases 9 rec5t times is relatively slight comp>$ ) ! :ole body ( ! e>?4 ,:at contribution may h come to ! e>? 9 e>li] times f su* s\rces is a matt] ( hypo!sis :i* w be discuss$ lat]4 ,geognosy4 ,! con/itution ( ! e>?4--,turn+ f its ext]nal relations to ! e>? itself1 a natural ?reefold division is pres5t$3 7#a7 ! atmosph]e1 7#b7 ! hydrosph]e1 & 7#c7 ! li?osph]e4 ,i4 ,! ,atmosph]e4 ,! atmosph]e is an intimate mixture ( 7#a7 all ^? sub/ances t _c take a liquid or solid /ate at ! temp]atures & pressures :i* prevail at ! e>?'s surface1 toge!r ) 7#b7 su* transi5t vapors z ! v>i\s sub/ances ( ! e>? ?r[ (f4 ,! fir/ class =m ! p]man5t gases ( ! atmosph]e1 & consi/ ( nitrog5 ab\t #gi p>ts1 oxyg5 ab\t #ba p>ts1 c>bon dioxide ab\t 4#jc "p1 toge!r ) small quantities ( argon1 neon1 x5on1 krypton1 helium1 & o!r r>e con/itu5ts4 ,! second class are ! transi5t & fluctuat+ con/itu5ts ( ! atmosph]e1 *ief among :i* is aque\s vapor1 :i* v>ies greatly 9 am\nt accord+ to temp]ature1 pressure1 & o!r conditions4 ,to ?is are to be add$ volcanic emanations & a great v>iety ( volatile organic sub/ances4 ,!oretically1 e sub/ance1 h[ev] solid1 dis*>ges p>ticles :i* may transi5tly become con/itu5ts ( ! atmosph]e4 ,practically1 only a few ( ^! exi/ 9 su* quantity z to be appreciable4 ,du/ & o!r susp5d$ matt] are usually reg>d$ z impurities r ?an con/itu5ts ( ! atmosph]e1 b !y play a n unimportant "p by affect+ its temp]ature & lum9osity1 & by facilitat+ ! cond5sation ( moi/ure4 ,mass & ext5t4--,! total mass ( ! atmosph]e is e/imat$ at five quadrillion tons1 or ( ! mass ( ! e>?4 ,x is relatively d5se at ! surface ( ! e>? & decreases 9 d5sity outw>ds 9 a mann] difficult ( absolute det]m9ation1 s t ! actual height ( ! appreciable atmosph]e is n positively kn[n4 ,! true conception ( ! atmosph]e is p]haps t ( a t5u\s envelope ex]t+ a pressure ( ab\t fifte5 p\nds p] squ>e in* at ! sea-level1 & ?9n+ gradually upw>ds until x rea*es a t5uity :i* is inappreciable1 b p]haps n ceas+ absolutely until ! sph]e ( gravitative control ( ! e>? is pass$1 ab\t #fbj1jjj miles f ! li?osph]e4 ,9 ! l[] portion1 accord+ to ! k9etic !ory ( gases1 ! molecules fly to & fro1 collid+ ) ea* o!r ) almo/ inconceivable frequ5cy1 & ) v %ort pa?s betwe5 successive collisions1 b 9 ! upp] r>e portion "s ( ! molecules b\nd outw>ds1 & d n /rike o!r molecules1 & h5ce pursue long elliptical pa?s until ! gravity ( ! e>? ov]comes _! mom5tum1 :5 !y return1 p]haps to b\nd (f aga9 or to =ce o!r molecules to d s4 ,?is f\nta9-l nature ( ! out] "p ( ! atmosph]e makes any %>p def9ition ( its limit impracticable4 ,"s molecules are believ$ to be %ot away at su* spe$ t !y d n return4 ,beyond ab\t #fbj1jjj miles f ! surface ( ! li?osph]e1 ! diff]5tial attraction ( ! sun is great] ?an t ( ! e>?1 & if ! attraction ( ! e>? does n turn ! molecules back be=e rea*+ ?is di/ance1 !y are almo/ c]ta9 to be lo/ to ! e>?4 ,! measurem5t ( heights by ! an]oid b>omet]1 :i* is mu* us$ 9 practical geology1 is dep5d5t on ! less5+ ( pressure z ! in/rum5t is c>ri$ upw>d4 ,geologic activity4--,! atmosph]e is ! mo/ mobile & active ( ! ?ree great subdivisions ( ! e>?1 & :5 its indirect effects ?r\gh ! ag5cy ( wat]1 z well z its direct effects1 are consid]$1 x is to be reg>d$ z "o ( ! mo/ effective ag5cies ( *ange4 ,x acts *emically ^u ! rock sub/ance ( ! e>?1 caus+ induration 9 "s in/ances1 b m (t5 induc+ dis9tegration & *ange ( composition by means ( :i* rock is r$uc$ to soil1 or soil-l mat]ial1 & r5d]$ susceptible ( easy removal by w9ds & wat]s4 ,:5 9 motion ! atmosph]e acts me*anically on ! surface ( ! e>?1 transport+ du/ & s&1 & by ! friction ( ^! x abrades ! surface4 ,x is *iefly effective1 h[ev]1 9 furni%+ ! conditions = wat] action4 ,p>tly by its me*anical aid1 b *iefly by secur+ ! "r temp]ature1 x is a necess>y factor 9 ! action ( ra9s1 /reams1 glaci]s1 & ! v>i\s =ms ( mov+ wat] ^u l&4 ,s also1 on ! ocean1 wave action is ess5tially dep5d5t on ! w9ds4 ,9 ! abs5ce ( atmosph]ic propulsion1 wave action w\ld be *iefly conf9$ to ! tides & to occasional e>?quake impulses1 & w\ld lose ne>ly all its effici5cy4 ,/ream action & wave action1 :i* are ! mo/ decl>$ ( ! geological ag5cies1 are !re=e to be cr$it$ z mu* to ! atmosph]e z to ! hydrosph]e1 s9ce ! action is a jo9t "o to :i* bo? envelopes are ess5tial4 ,a !rmal blanket4--,a function ( ! atmosph]e ( supreme importance is ! !rmal blanket+ ( ! e>?4 ,9 its abs5ce ! heat ( ! sun w\ld rea* ! surface ) full int5sity1 & w\ld be radiat$ back f ! surface almo/ z rapidly z receiv$1 & only a transi5t heat+ w\ld result4 ,dur+ ! night an int5sity ( cold w\ld int]v5e sc>cely less sev]e ?an ! temp]ature ( space4 ,9 p5etrat+ ! atmosph]e c]ta9 portions ( ! radiant en]gy ( ! sun are absorb$4 ,( ! rema9d] :i* rea*es ! surface ( ! e>?1 a "p is trans=m$ into vibrations ( l[] int5sity1 :i* are !n m effectively reta9$ by ! atmosph]e4 ,! air ?us di/ributes & equalizes ! temp]ature4 ,! two con/itu5ts ( ! atmosph]e :i* are mo/ effici5t 9 ?is "w are aque\s vapor & c>bon dioxide1 & ! climate ( ! e>? is believ$ to h be5 v greatly affect$ by ! v>y+ am\nts ( ^! con/itu5ts 9 ! atmosph]e1 z well z by ! total mass ( ! atmosph]e4 ,! function ( ! atmosph]e 9 su/a9+ life & promot+ all t dep5ds on life is too obvi\s to ne$ comm5t4 ,! special geological action ( ! atmosph]e w be discuss$ 9 ! next *apt]4 ,,ii4 ,! ,hydrosph]e4 ,ab\t #acjj quadrillion tons ( wat] lie ^u ! surface ( ! solid e>?4 ,?is equals ab\t "p ( ! e>?'s mass4 ,7 ! surface ( ! solid e>? p]fectly sph]oidal1 ?is w\ld con/itute a univ]sal ocean some:at less ?an two miles deep4 ,ow+ to ! inequalities ( ! rock surface1 ! wat] is *iefly ga!r$ into a s]ies ( great bas9s or tr\ghs occupy+ ab\t ?ree-f\r?s 7#gb7 ( ! e>?'s surface4 ,^! bas9s are all connect$ ) ea* o!r & act z a unit1 s t any?+ :i* *anges ! level ( ! wat] 9 "o *anges ! level ( all4 ,?is helps to make a common record ( all great movem5ts ( ! e>?'s body1 = ! level ( ! ocean det]m9es :]e ! detritus f ! l& %all lodge1 & h5ce :]e ! edge ( ! m>9e b$s %all be =m$4 ,?is w appe> m cle>ly :5 ! =mation ( m>9e /rata is discuss$4 ,oceanic dim5sions4--,! surface area ( ! ocean is e/imat$ by ,murray at #adc1bei1cjj squ>e miles4 ,( ?is1 some:at m ?an #aj1jjj1jjj squ>e miles lie on ! cont95tal %elf1 i4e41 lap up on ! bord]s ( ! cont95tal plat=ms4 ,?is %[s t ! great bas9s are some:at m ?an full4 ,if ab\t #fjj feet ( ! upp] "p ( ! ocean 7 remov$1 ! true ocean bas9s w\ld be j full1 & ! surfaces ( ! true cont95tal plat=ms w\ld be dry l&4 ,! area ( ! true oceanic bas9s is ab\t #acc1jjj1jjj squ>e miles1 & t ( ! true cont95tal plat=ms ab\t #fd1jjj1jjj squ>e miles4 ,"u ab\t #bj ( ! ocean area1 ! bottom s9ks to dep?s betwe5 #fjjj & #ab1jjj feet2 "u ab\t #ec x s9ks to dep?s betwe5 #ab1jjj & #ah1jjj feet2 & "u ! rema9+ #d x ranges f #ah1jjj feet d[n to ab\t #cj1jjj4 ,! la/ includes ^? s+ul> sunk5 areas kn[n z 8deeps10 & sometimes call$ anti-plateaus1 z !y ext5d d[nw>d f ! g5]al ocean bottom mu* z ! plateaus protrude upw>ds f ! g5]al l& surface4 ,besides ! ocean1 ! hydrosph]e includes all ! wat] :i* con/itutes ! surface /reams & lakes1 toge!r ) t :i* p]meates ! pores & fissures ( ! out] "p ( ! solid e>?2 b altoge!r ^! are small 9 am\nt comp>$ ) ! great ocean mass4 ,geologic activity4--,( all geological ag5cies wat] is ! mo/ obvi\s & app>5tly ! greate/1 ?\gh its effici5cy is condition$ ^u ! pres5ce ( ! atmosph]e1 ^u ! relief ( ! l&1 & ^u ! radiant en]gy ( ! sun4 ,?r\gh ! ag5cy ( ra9fall1 ( surface /reams1 ( und]gr\nd wat]s1 & ( wave action1 ! hydrosph]e is con/antly modify+ ! surface ( ! li?osph]e1 :ile at ! same "t x is be>+ into ! v>i\s bas9s ! wa% ( ! l& & deposit+ x 9 /ratifi$ b$s4 ,x !reby becomes ! great ag5cy = ! degradation ( ! l& & ! build+ up ( ! bas9 bottoms4 ,x works ^u ! l& p>tly by dissolv+ soluble portions ( ! rock sub/ance1 & p>tly by me*anical action4 ,! solution ( ! soluble "p usually loos5s ! insoluble1 & r5d]s x an easy prey ( ! surface wat]s4 ,^! transport ! loos5$ mat]ial to ! valleys & at l5g? to ! great bas9s1 mean:ile roll+ & gr9d+ x & ?us r$uc+ x to r\nd] =ms & a f9] /ate1 until at l5g? x rea*es ! /ill wat]s or ! l[ gradi5ts ( ! bas9s & comes to re/4 ,! hydrosph]e is !re=e bo? de/ructive & con/ructive 9 its action4 ,z ! b$s ( s$im5t :i* x lays d[n foll[ "o ano!r 9 ord]ly succession1 ea* lat] "o ly+ above ea* e>li] "o1 !y =m a "t record4 ,& z relics ( ! life ( ea* age become m or less imb$d$ 9 ^! s$im5ts1 !y furni% ! means ( foll[+ ! hi/ory ( life f age to age4 ,! hi/orical record ( geology is !re=e v l>gely dep5d5t ^u ! fact t ! wat]s h ?us buri$ 9 sy/ematic ord] ! successive life ( ! ages4 ,aside f ?is1 ! means ( det]m9+ ! ord] ( ev5ts ( ! e>?'s hi/ory are limit$ & m or less unc]ta94 ,! special processes ( ! hydrosph]e 9 its v>i\s phases w be ! subject ( discussion h]eaft] 7,*aps4 ,,iii1 ,,iv1 ,,vi74 ,suffice x "h to recognize its great function 9 ! con/ant degradation ( ! l&1 & 9 ! deposition ( ! d]iv$ mat]ial 9 ord]ly succession 9 ! bas9s4 ,*ief horizons ( activity4--,! great horizons ( geological activity are 7#a7 ! contact zone betwe5 ! atmosph]e & ! hydrosph]e1 *iefly ! surface ( ! ocean1 7#b7 ! contact zone betwe5 ! hydrosph]e & ! li?osph]e1 *iefly ! %ore belts1 & 7#c7 ! contact zone ( ! atmosph]e & surface wat]s1 ) ! face ( ! cont95ts4 ,x is 9 ^! ?ree zones t ! greate/ ext]nal "w is be+ done & has be5 done 9 all ! kn[n ages4 ,,iii4 ,! ,li?osph]e4 ,! atmosph]e & hydrosph]e are r envelopes or %ells ?an true sph]es1 ?\gh 9 "s degree bo? p5etrate ! li?osph]e4 ,! li?osph]e1 on ! o!r h&1 is a ne>ly p]fect oblate sph]oid ) a pol> diamet] ( #ghii4g miles1 & an equatorial diamet] ( ab\t #bf4h miles m4 ,its equatorial circumf]5ce is #bd1ijb miles1 its m]idional circumf]5ce #bd1hfj miles1 its surface area #aif1idj1gjj squ>e miles1 its volume #bfj1jjj1jjj1jjj cubic miles1 & its av]age specific gravity ab\t #e4eg4 ,! oblat5ess ( ! sph]oid is an accommodation to ! rotation ( ! e>?1 ! c5trifugal =ce at ! equator be+ suffici5t to cause ! specifi$ am\nt ( bulg+ !re4 ,computations seem to indicate t ! accommodation is v ne>ly :at w\ld take place if ! e>? 7 9 a liquid condition1 f :i* ! inf]5ce has be5 drawn t x mu/ h be5 9 t condition :5 x assum$ ?is =m1 & mu/ h cont9u$ ess5tially liquid until x atta9$ its pres5t rate ( rotation1 s9ce1 if ! e>? once rotat$ at a mu* high] spe$1 ! flatt5+ at ! poles & ! bulg+ at ! equator mu/ h be5 correspond+ly great]4 ,x is ?\ght by o!rs1 h[ev]1 t ! pla/icity ( ! e>? is su* t x w\ld at all times assume a close degree ( approximation to ! dem&s ( rotation1 ev5 if ! int]ior 7 9 a solid condition4 ,by /ill o!rs x is ?\ght t ! contraction ( ! e>? has t5d$ to accel]ate ! rotation ab\t z mu* z ! tides h t5d$ to ret>d x1 & t x has und]gone little *ange ( =m4 ,irregul>ities4--,x is only 9 a g5]al view1 h[ev]1 t !re is a close approximation to a p]fect sph]oidal surface4 ,9 detail !re are v notable v>iations f x4 ,geodetic surveys seem to h %[n t ! equatorial diamet]s are n all equal1 ev5 :5 ! measurem5ts are r$uc$ to sea-level1 b rese>* along ?is l9e has n rea*$ a suffici5t /age ( complet5ess to p]mit satisfactory discussion4 ,x is1 h[ev]1 highly probable t ! ocean surface z well z ! av]age l& surface is w>p$ out ( ! p]fect sph]oidal =m to "s notable degree4 ,?is is v likely due to inequalities 9 ! d5sity ( ! e>?'s int]ior4 ,! fact t ! l>g] portion ( ! wat] is ga!r$ on "o side ( ! globe1 :ile ! l& *iefly protrudes on ! opposite side1 is v possibly due to unequal specific gravity 9 ! int]ior ( ! e>?4 ,! mo/ obvi\s dep>ture f a sph]oidal =m is f\nd 9 ! protrusion ( ! cont95ts & 9 ! s9k+ away ( ! e>? surface "u ! oceans4 ,z ^! inequalities pres5t !mselves to-day1 !y are kn[n z cont95tal plat=ms & ocean bas9s4 ,^! d n correspond accurately ) ! pres5t l& & wat] surfaces4 ,ab\t ! cont95tal l&s !re is a subm]g$ bord] ext5d+ "s di/ance out f ! %ore1 & con/itut+ a sea-%elf beyond :i* ! surface desc5ds rapidly to ! great dep?s ( ! ocean4 ,?is slightly subm]g$ portion1 kn[n z ! cont95tal %elf1 belongs z prop]ly to ! cont95t z ! adjac5t l[ l&s :i* are n subm]g$4 ,! subm]g5ce ( ! edge ( ?is %elf at pres5t is usually ab\t #ajj fa?oms1 s t if ! upp] #fjj feet ( ! ocean 7 remov$1 ! outl9es ( ! l& w\ld correspond q closely ) ! bord] ( ! true cont95tal plat=m4 ,illu/ration3 ,,ba?ymetrical ,,*>t ,,( ,,! ,,oceans ,,%[+ ,,! 8,,deeps0 ,,accord+ ,,to ,,sir ,,john ,,murray ,x is cu/om>y to look ^u ! protrusions ( ! cont95ts z ! great features ( ! e>?'s surface1 b 9 reality ! oceanic depressions are ! ma/] ph5om5a4 ,9 bread?1 dep?1 & capacity !y mu* exce$ ! cont95tal protrusions1 & if ! e>? be reg>d$ z a %runk5 body1 ! settl+ ( ! ocean bottoms has d\btless con/itut$ its greate/ surface movem5t4 ,f ! e/imates ( ,murray1 ,gilb]t has d]iv$ ! foll[+ tables1 %[+ ! relative areas ( ! li?osph]e above1 bel[1 & betwe5 c]ta9 levels4#a ,f ^! e/imates x appe>s t if ! surface 7 grad$ to a common level by cutt+ away ! cont95tal plat=ms & dump+ ! matt] 9 ! abysmal bas9s1 ! av]age plane w\ld lie some:]e ne> #ijjj feet bel[ ! sea-level4 ,! cont95tal plat=m may be conceiv$ z ris+ f ?is common plane r ?an f ! sea-level4 ---------------------------------------- --------------------------- ,p]c5t4 ( ,p]c5t4 ( ,cont\rs4 ,surface ,surface above4 bel[4 ---------------------------------------- --------------------------- ,cont\r #bd1jjj feet above sea-level #j4jjd #ii4iif #ah1jjj #j4ji #ii4ia #ab1jjj #j4g #ii4c #f1jjj #b4c #ig4g ,sea level #bg4g #gb4c ,cont\r #f1jjj feet bel[ sea-level #db4e #eg4e #ab1jjj #eg4c #db4g #ah1jjj #if4h #c4b #bd1jjj #ii4ic #j4jg ---------------------------------------- --------------------------- ,p]c5t4 ,m ?an #fjjj feet above sea-level #b4c ,betwe5 sea-level & #fjjj feet above #be4e ,betwe5 sea-level & #fjjj feet bel[ #ad4h ,betwe5 #fjjj & #ab1jjj feet bel[ sea-level #ad4h ,betwe5 #ab1jjj & #ah1jjj feet bel[ sea-level #ci4d ,betwe5 #ah1jjj feet & #bd1jjj feet #c4a ,epicont95tal seas4--,^? %all[ portions ( ! sea :i* lie ^u ! cont95tal %elf1 & ^? portions :i* ext5d into ! int]ior ( ! cont95t ) l %all[ dep?s1 su* z ! ,baltic ,sea & ! ,hudson ,bay1 may be call$ epicont95tal seas1 = !y really lie ^u ! cont95t1 or at lea/ ^u ! cont95tal plat=m2 :ile ^? o!r deta*$ bodies ( wat] :i* occupy deep depressions 9 ! surface are to be reg>d$ z true abysmal seas1 z1 = example1 ! ,m$it]ranean & ,c>ibbean seas & ! ,gulf ( ,mexico1 ^: bottoms are z pr(\nd z _m p>ts ( ! true ocean bas9 itself4 ,div]sities ( surface4--,! bottoms ( ! oceanic bas9s are div]sifi$ by broad undulations :i* range ?r\gh _m ?\s&s ( feet1 b !y are n c>v$ into ! div]sifi$ =ms t give v>iety to l& surfaces4 ,! ocean bottoms are also div]sifi$ by volcanic peaks1 _m ( :i* rise to ! surface & con/itute isolat$ isl&s4 ,"s ( !m h notable plat=ms at or ne> ! surface1 cut by ! waves or built up by ! accumulation ( s$im5t & ( corall9e & o!r gr[?s ab\t !m4 ,aside f ^! encircl+ plat=ms1 ! solid surface usually %elves rapidly d[n to abysmal dep?s1 s t ! isl&s con/itute peaks ^: heights & slopes w\ld seem extraord9>y if ! ocean 7 remov$4 ,! surface ( ! l& is div]sifi$ 9 a simil> way by broad undulations & volcanic peaks1 & also by n>r[] wr9kl+s & fold+s ( ! cru/2 b all ( ^! irregul>ities h be5 c>v$ into div]sifi$ & picturesque =ms by subarial erosion4 ,9 ?is respect ! surface ( ! l& diff]s radically f ! b$ ( ! sea4 ,! ag5cies :i* h produc$ ! cont95tal plat=ms & abysmal bas9s1 & ! great undulations & fold+s1 z well z ! volcanic extrusions t m>k !m1 are yet subjects ( debate4 ,"h lie "s ( ! mo/ difficult problems ( geology1 b ^! _c be /at$ ) suffici5t brevity to f9d a place "h4 ,! surface mantle ( ! li?osph]e4--,! surface ( ! li?osph]e is v g5]ally mantl$ by a lay] ( loose mat]ial compos$ ( soil1 clay1 s&1 gravel1 & brok5 rock4 ,?is loose mat]ial is sometimes kn[n z mantle rock1 & sometimes z rock wa/e4 ,on ! l&1 mantle rock is (t5 compos$ ( ! dis9tegrat$ products ( und]ly+ rock =mations4 ,x repres5ts ! results ( ! rec5t action ( ! atmosph]e1 ( wat]1 ( *anges ( temp]ature1 & ( o!r physical ag5cies act+ on ! out] "p ( ! rock sph]e4 ,! surface ( ?is mantle is be+ con/antly remov$ by w9d & wat]1 b z con/antly r5ew$ by cont9u$ decomposition ( ! rock bel[4 ,9 "s areas1 especially 9 ! nor!rn "p ( ,nor? ,am]ica & ! nor?we/]n "p ( ,europe1 ! soil graduates d[n into an irregul> %eet ( mix$ clay1 s&1 gravel1 & b[ld]s1 kn[n z drift4 ,f ?is & o!r evid5ce x is inf]r$ t at a "t n greatly ant$at+ our own1 ice1 *iefly 9 ! =m ( glaci]s1 spread ext5sively ov] ! high latitudes ( ! nor!rn hemisph]e4 ,9 "s p>ts ( ! e>? ! surface is /ill cov]$ by fields ( sn[ & ice1 comp>able to ^? :i* =m$ ! drift4 ,9 /ill o!r places1 especially along ! flood pla9s ( /reams1 ! mantle rock consi/s ( deposits made by /reams :i* 7 unable to c>ry _! loads ( s$im5t to ! sea4 ,! cru/ ( ! li?osph]e4--,mu* ( ! detritus wa%$ d[n f ! l& f9ds its way to bodies ( /&+ wat]1 & b5ea? lakes & seas ! mantle ( loose mat]ial is made up l>gely ( ! gravel1 s&1 & mud d]iv$ f ! l&4 ,be=e deposition ^! mat]ials are m or less assort$ & arrang$ 9 lay]s by waves & curr5ts4 ,:5 consolidat$ !y con/itute rock4 ,! wea!r+ ( ! rocks ( ! l&1 ! we>+ away ( ! result+ detritus1 & its deposition b5ea? /&+ wat]1 are among ! mo/ important processes ( geologic *ange4 ,on ! l&1 ! mantle ( loose mat]ial is sometimes abs5t1 & 9 su* places ! surface ( solid rock ( ! cru/ appe>s4 ,b>e surfaces ( rock are mo/ commonly se5 :]e ! topography is r\gh1 especially on ! slopes ( /eep-sid$ valleys & m\nta9s1 & on ! slopes ( cliffs :i* face seas or lakes4 ,solid rock1 )\t cov]+ ( soil or loose mat]ial ( any sort1 is also frequ5tly se5 9 ! *annels ( /reams1 especially :]e !re are falls or rapids4 ,we h b to note ! effects ( a vigor\s %[] on a /eep slope1 or ( a swift /ream on its *annel1 or ( waves on ! cliffs :i* face lakes & seas1 to und]/& at lea/ "o ( ! reasons :y loose mat]ials are frequ5tly abs5t f /eep slopes4 ,! v g5]al exposure ( solid rock :]e conditions favor surface erosion sugge/s t rock is ev]y:]e pres5t b5ea? ! soil or subsoil4 ,=tunately !re is an easy way ( te/+ ! univ]sality ( ! cru/ b5ea? ! mantle4 ,9 all l&s inhabit$ by civiliz$ peoples !re are num]\s wells & o!r excavations rang+ f a few feet to sev]al hundr$ feet 9 dep?1 & occasional wells & m9e-%afts rea* dep?s ( sev]al ?\s& feet4 ,ev5 9 %all[ excavations rock is (t5 enc\nt]$1 & 9 mo/ regions excavations z mu* z two or ?ree hundr$ feet deep usually rea* rock1 & no really deep bor+ has ev] fail$ to f9d x4 ,x may1 !re=e1 be accept$ z a fact t ! upp] surface ( ! solid rock is n[h]e f> bel[ ! surface4 ,conc]n+ ! ?ickness ( ! cru/1 if !re be any true cru/ at all1 little is kn[n by direct obs]vation4 ,! deepe/ valleys1 su* z ! canyon ( ! ,colorado1 & ! %afts & bor+s ( ! deepe/ m9es & wells1 give k ( no?+ b rock4 ,! deepe/ excavations ext5d r>ely m ?an a mile bel[ ! surface4 ,x is c]ta9 t rock ( kn[n k9ds ext5ds to f> great] dep?s4 ,! int]ior4--,conc]n+ ! great int]ior ( ! e>?1 little is kn[n except by inf]5ce4 ,f ! weight ( ! e>?1#b x is inf]r$ t its int]ior is mu* m d5se ?an its surface4 ,f its behavior "u ! attraction ( o!r bodies1 x is believ$ to be at lea/ z rigid z /eel1 & its int]ior _c1 !re=e1 be liquid1 9 ! usual s5se ( t t]m4 ,f ! ph5om5a ( volcanoes1 & f obs]vations on temp]ature 9 deep bor+s1 x is inf]r$ t its int]ior is v hot4 ,fur!r inf]5ces conc]n+ its "* are less simply /at$1 & w be ref]r$ to lat]4 ,! solid "p ( ! e>? is !re=e compos$ ( 7#a7 a ?9 lay] ( unconsolidat$ or e>?y mat]ial1 a few feet to a few hundr$ feet 9 ?ickness1 cov]+ 7#b7 a lay] or zone _m ?\s&s ( feet1 & probably _m miles1 ?ick1 compos$ ( solid rock comp>able to t expos$ at num]\s po9ts on ! surface1 & 7#c7 a c5tral mass1 to :i* ! prec$+ lay]s are b a %ell1 compos$ ( hot1 d5se1 & rigid rock1 ! real nature ( :i* is n kn[n by obs]vation4 ,v>ieties ( rock 9 cru/4--,if ! mantle ( soil1 subsoil1 & glacial rubbi% 7 /ripp$ f ! l&1 ! surface b5ea? w\ld be f\nd to be made up ( a great v>iety ( rocks1 all ( :i* may be gr\p$ into two great classes4 ,ab\t f\r-fif?s ( ! l& surface w\ld be ( rock arrang$ 9 lay]s1 & ! o!r fif? w\ld be ( cry/all9e rock1 g5]ally )\t di/9ct /ratification1 & (t5 be>+ evid5ce ( ! effects ( high temp]ature4 ,/ratifi$ rocks4--,! composition ( mo/ /ratifi$ rocks corresponds some:at closely ) ! composition ( s$im5ts n[ be+ c>ri$ f ! l& & be+ deposit$ 9 ! sea4 ,_! arrangem5t 9 lay]s is ! same1 & ! m>k+s on ! surfaces ( ! lay]s1 su* z ripple-m>ks1 rill-m>ks1 wave-m>ks1 etc41 are id5tical4 ,fur!rmore1 ! /ratifi$ rocks ( ! l&1 l ! rec5t s$im5ts ( ! sea1 frequ5tly conta9 ! %ells & skeletons ( animals1 & sometimes ! impressions ( plants4 ,mo/ ( ! relics ( life f\nd 9 ! /ratifi$ rocks belong$ to animals or plants :i* liv$ 9 salt wat]4 ,because ( _! /ructure1 _! composition1 _! di/9ctive m>k+s1 & ! rema9s ( life :i* !y conta91 x is confid5tly inf]r$ t mo/ ( ! /ratifi$ rocks :i* lie b5ea? ! mantle rock ( ! l& 7 orig9ally laid d[n 9 b$s b5ea? ! sea1 & t ! famili> processes ( ! pres5t "t furni% ! key to _! hi/ory4 ,illu/ration3 ,fig4 #a4--;,b$s ( 7,cambrian7 s&/one1 a1 are con=mable ) "o ano!r1 b uncon=mable on b$s ( 7,huronian7 qu>tzite1 b1 ,ne> ,ableman1 ,wis4 ,con=mability4--,:5 ! /ratifi$ rocks expos$ by ! removal ( ! mantle rock are exam9$1 ! successive b$s are sometimes f\nd to lie on "o ano!r 9 regul> succession1 %[+ t !y 7 laid d[n "o aft] ano!r1 )\t *ange 9 ! attitude ( ! surface on :i* !y 7 deposit$4 ,su* rocks are con=mable 7! b$s ( s]ies a1 ,fig4 #a74 ,9 o!r cases x w\ld be se5 t c]ta9 b$s ov]lie ! worn surfaces ( l[] b$s1 ! lay]s ( :i* may h a diff]5t angle ( incl9ation 7s]ies a1 ,fig4 #a1 is uncon=mable on s]ies b74 ,su* relations %[ t ! l[] s]ies ( b$s 0 di/urb$ & erod$ be=e ! ov]ly+ b$s 7 deposit$ on !m4 ,su* s]ies ( rocks are uncon=mable4 ,relative ages4--,! /ructure & relations ( rocks lead to inf]5ces z to _! relative ages4 ,9 ! case ( /ratifi$ rocks x is obvi\s t ov]ly+ b$s 7 deposit$ lat] ?an ^? bel[1 & :]e !re is uncon=mity x is evid5t t an int]val ( "t elaps$ betwe5 ! deposition ( ! uncon=mable s]ies4 ,ano!r & 9 "s respects m important means ( tell+ _! ord] ( =mation is f\nd 9 ! rema9s ( life entrapp$ 9 ! wat]-laid s$im5ts4 ,:atev] life exi/$ 9 ! wat]s 9 :i* ! s$im5ts 7 deposit$ 0 liable to burial1 & if x 0 possess$ ( h>d p>ts1 su* z bones1 tee?1 %ells1 h>d integum5ts1 etc41 ^! p>ts1 or at lea/ _! impressions1 7 likely to be pres]v$ 9 ! s$im5ts4 ,ev5 tracks & impr9ts ( p]i%able p>ts are sometimes pres]v$4 ,all ^! relics1 :i* we call fossils1 give indications ( ! k9ds ( life :i* exi/$ :5 ! b$s 7 =m$4 ,! fossils ( ! y\nge/ b$s %[ t ! life :i* exi/$ :5 !y 7 deposit$ 0 q l t ( ! pres5t "t4 ,! fossils ( ! next old] & l[] b$s %[ great] dep>ture f pres5t types4 ,?is s]ies ( *anges cont9ues d[nw>d z l[] & l[] b$s are /udi$1 until b$s at consid]able dep?s conta9 no relics ( exi/+ species b1 9 lieu !re(1 =ms ( m primitive types4 ,"s ( ^! e>li] types are cle>ly ! ance/ors ( m mod]n =ms1 :ile o!rs seem to h no liv+ desc5dants4 ,go+ /ill deep]1 ! fossils indicate life ( m & m primitive types1 until !y dep>t v widely f ! liv+ =ms1 & seem to be b remotely ance/ral4 ,s ! b$s may be foll[$ d[nw>d until ! l[e/1 :i* conta9 di/9ct evid5ces ( life1 are rea*$4 ,x %\ld be und]/ood t x is n possible to proce$ directly d[nw>d ?r\gh ! :ole succession ( b$d$ rocks1 b t ! edges ( ! v>i\s b$s may be f\nd "h & !re :]e !y h be5 br\ght to ! surface by w>p+s or tilt+s1 or expos$ by ! we>+ away ( ! b$s :i* once ov]lay !m4 ,! full s]ies ( /rata is made out only by putt+ toge!r ! data ga!r$ ?r\gh\t all l&s1 & ev5 :5 ?is is done an absolutely complete s]ies _c yet be made out or1 at lea/1 has n be54 ,! cry/all9e rocks4--,! cry/all9e rocks :i* w\ld appe> if ! mantle rock 7 remov$ are ( two types1 igne\s & metamorphic4 ,igne\s rocks may be loosely def9$ z h>d5$ lavas4 ,metamorphic rocks are ^? :i* are greatly *ang$ f _! orig9al condition4 ,ei!r /ratifi$ or igne\s rocks may become metamorphic4 ,igne\s rocks su/a9 v>i\s relations to ! /ratifi$ rocks1 z illu/rat$ by ,fig4 #b4 ,f ^! relations x is possible to tell some?+ ( ! ord] ( _! =mation4 ,:]e ! /ratifi$ rocks are brok5 ?r\gh by lavas1 x is obvi\s t ! /ratifi$ rocks 7 =m$ fir/1 & ! lavas intrud$ lat]4 ,lava %eets intrud$ betwe5 b$s ( /ratifi$ rock c be told f ^? :i* fl[$ out on ! surface & 7 subsequ5tly buri$1 = 9 ! =m] case ! s$im5t>y rocks1 bo? above & bel[ ! igne\s rock1 7 affect$ by ! heat1 :ile 9 ! latt] case only ^? bel[ 7 s affect$4 ,illu/ration3 ,fig4 #b4--;,diagrammatic repres5tation ( ! relations ( igne\s rock to /ratifi$ rock4 ,! igne\s rocks1 repres5t$ 9 black1 h be5 =c$ up f b5ea?4 ,m commonly ?an o!rwise ! metamorphic rocks 7,fig4 #c7 lie b5ea? ! s$im5t>y b$s & are (t5 brok5 ?r\gh by ! igne\s rocks4 ,f _! position 9 _m places _! great age may be inf]r$1 b locally1 especially :]e dynamic action has be5 sev]e1 relatively "y rocks are metamorphic4 ,illu/ration3 ,fig4 #c4 ,! figure repres5ts a section ( ! e>? ab\t #ajjj miles long4 ,! unequally ?ick black l9e at ! top repres5ts on some?+ l its prop] scale ! dep? ( ! /ratifi$ rock4 ,! area bel[ repres5ts cry/all9e rock1 l>gely metamorphic4 ,f\r great s$im5t>y eras4--,! wat]-laid s]ies repres5ts f\r great eras 9 ! hi/ory ( ! e>?1 z %[n by ! relics ( life imb$d$ 9 !m4 ,beg9n+ ) ! late/1 ^! are ! ,c5ozoic 7rec5t life71 dur+ :i* ! life took on its mod]n aspect2 ! ,mesozoic 7middle life71 dur+ :i* ! life bore a m$ival aspect2 ! ,paleozoic 7anci5t life71 dur+ :i* ! life belong$ to old] types2 & ! ,prot]ozoic 7e>li] life71 dur+ :i* x is inf]r$ t mu* life prevail$1 ?\gh its record is v imp]fect4 ,x may safely be assum$ to h be5 m primitive ?an t ( ! ,paleozoic1 z x 0 e>li]4 ,ea* ( ^! great divisions embrac$ sev]al less] p]iods or epo*s1 & ^! aga9 are subdivid$ m & m closely accord+ to ! degrees ( ref9em5t to :i* /udies are c>ri$4 ,! *ief ( ^! subdivisions are giv5 9 ! table on page #ai1 & o!rs w come "u consid]ation 9 ! hi/orical *apt]s4 ,9 ^! f\r great s]ies ( s$im5t>y rocks !re are1 "h & !re1 intrusions ( igne\s rocks1 & 9 "s places ! s$im5t>y b$s h be5 metamorphos$ into cry/all9e rocks by heat & pressure4 ,?is is p>ticul>ly true 9 ! l[e/ ( ^! s]ies1 ! ,prot]ozoic1 :]e a l>ge "p ( ! s$im5t is metamorphos$1 & :]e !re is mu* igne\s rock1 b x is /ill cle> t ! ma9 portion ( ?is s]ies 0 orig9ally wat]-laid s$im5t1 & s x belongs to ! s$im5t>y s]ies r ?an ! ,ar*ean1 9 :i* ! s$im5ts are ! m9or r ?an ! ma9 factor4 ,x has1 h[ev]1 usually be5 class$ ) ! ,ar*ean1 & x is c]ta9ly n always easy to draw ! divid+ l9e4 ,9 a s5se x may be reg>d$ z a transition s]ies4 ,! ,ar*ean complex4--,b5ea? ! dom9antly s$im5t>y b p>tly metamorphic & igne\s s]ies !re is a v complex gr\p ( rocks l>gely ( metamorphos$ igne\s orig91 ?\gh conta9+ "s metamorphos$ s$im5ts4 ,^! ext5d d[nw>ds to unkn[n dep?s4 ,:ile all ! great =mations are occasionally b5t & brok51 ^! l[e/ ones are almo/ ev]y:]e w>p$1 fold$1 & contort$1 (t5 9 ! mo/ intricate way4 ,!y h be5 v g5]ally ma%$ & %e>$ by enorm\s pressure1 s t !y h become foliat$1 & _! orig9al "* is mu* mask$4 ,!y !re=e =m a s]ies ( great obscurity & complexity4 ,z !y are at ! bottom ( ! kn[n s]ies1 !y h be5 call$ ! 8,fundam5tal gneiss0 & ! 8,basem5t complex10 b z ! "p :i* we see is n ! true base nor ! true f\ndation1 x is saf] to call !m simply ! ,ar*ean 7v anci5t7 complex4 ,z life appe>s to h be5 pres5t dur+ a "p at lea/ ( ! p]iod ( its =mation is ref]r$ to ! ,ar*eozoic era4 ,illu/ration3 ,fig4 #d4--;,diagram to illu/rate ! relations ( ! five great gr\ps ( =mations4 ,,ar ,ar*ean1 ,pr ,prot]ozoic1 ,p ,paleozoic1 ,m ,mesozoic1 ,c ,c5ozoic4 ,beyond & bel[ ?is s]ies1 ! /ructure ( ! e>? is a matt] ( inf]5ce4 ,va/ z are ! prec$+ s]ies1 !y toge!r =m relatively b a ?9 %ell on ! out] surface ( ! globe4 ,! =ego+ s]ies are diagrammatically express$ 9 ,fig4 #d1 & sy/ematically pres5t$ to ! eye 9 ! foll[+ table4 ,,g5]al ,,table ,,( ,,geologic ,,divisions4 ,pres5t4 ,plei/oc5e4 ,plioc5e4 ,c5ozoic ,mioc5e4 ,oligoc5e4 ,eoc5e4 3 ,transition 7,arapahoe & ,d5v]74 ,upp] ,cretace\s4 ,mesozoic ,l[] ,cretace\s 7,coman*e or ,%a/an74 ,jurassic4 ,triassic4 ,p]mian4 ,coal ,measures or ,p5nsylvanian4 ,subc>bonif]\s1 or ,mississippian4 ,paleozoic ,devonian4 ,silurian4 ,ordovician4 ,cambrian4 ,great int]val4 ,kewe5awan4 ,int]val4 ,prot]ozoic ,animikean or ,p5okean4 7,upp] ,huronian ( "s au?ors74 ,int]val4 ,huronian4 ,great int]val4 ,great ,granitoid ,s]ies4 7,intrusive 9 ! ma91 ,laur5tian47 ,ar*eozoic ,ar*ean ,complex4 ,great ,s*i/ ,s]ies4 7,mona1 ,kit*i1 ,l[] ,keewat91 ,c\t*i*+1 ,l[] ,huronian ( "s au?ors47 ,! purpose ( ?is g5]al survey is to br+ ! sali5t features ( ! e>?'s /ructure into view prep>atory to ent]+ 9 m detail into ! /udy ( p>ticul> processes & special =mations & to lay a f\ndation = ! full] appreh5sion ( ! successive /ages ( ! hi/ory ( ! e>?1 :i* con/itutes ! *ief purpose ( geological /udy4 ,x is n[ advisable to turn to ! detail$ consid]ation ( individual processes & specific /ructures4 ,! complexity ( ! actions involv$ 9 ! hi/ory ( ! e>? is s great t su* sep>ate consid]ation at ! outset is helpful4 ,,*apt] ,,ii4 ,,! ,,atmosph]e ,,z ,a ,,geological ,,ag5t4 ,:ile x is conv5i5t to reg>d ! li?osph]e z ! e>? prop]1 & ! atmosph]e z its envelope1 ! latt] is z truly a "p ( ! planet z ! =m]1 & its activities & its hi/ory are z truly subjects ( geological /udy z ! =mation ( ! rocks4 ,?is view is 9 no way vitiat$ by ! fact t ! special /udy ( ! atmosph]e is set ap>t "u ! "n ,meteorology1 = 9 ! same way ! special /udy ( rocks is set ap>t "u ! "n ,petrology1 t ( anci5t life "u ! "n ,paleontology1 & t ( o!r phases ( ! subject "u o!r names4 ,! atmosph]e is "o ( ! ?ree great =mations ( ! e>?1 & z a geological factor takes its place beside ! hydrosph]e & ! li?osph]e4 ,x has play$ a "p 9 ! hi/ory ( ! e>? comp>able to t ( ! wat]1 ?\gh its mass is less & its record m elusive4 ,unsub/antial z ! atmosph]e seems :5 contra/$ ) ! liquid & solid portions ( ! e>?1 its extreme mobility & its *emical activity comp5sate = its lightness & t5uity1 & give x a function ( ! fir/ ord] ( importance4 ,! atmosph]e plays a direct "p z 7#a7 a me*anical & 7#b7 a *emical ag5t1 & at ! same "t s]ves an indirect function 9 furni%+ favorable conditions "u :i* 7#c7 sol> radiation produces temp]ature effects1 & 7#d7 evaporation gives orig9 to precipitation & /ream effects1 & furni%es ! necess>y conditions = l& plants & animals1 & ! important influ5ces t spr+ f !m4 ,?is *apt] is devot$ to ! "w ( ! atmosph]e 9 ^! & "s less notable phases4 ,! consid]ation ( ! orig9 & hi/ory ( ! atmosph]e w receive att5tion lat]4 ,a4 ,,! ,,atmosph]e ,,z ,a ,,direct ,,ag5cy4 ,i4 ,me*anical ,"w4 ,! me*anical "w ( ! atmosph]e is accompli%$ *iefly ?r\gh its movem5t4 ,a feeble breeze is compet5t to move p>ticles ( du/1 & w9ds ( mod]ate velocity to %ift s&4 ,exceptionally /rong w9ds sometimes move small pebbles1 b w9ds ( suffici5t =ce to move l>g] pieces ( rock are r>e4 ,x foll[s1 !re=e1 t ! impact ( ! w9d has little direct effect except on surfaces cov]$ ) du/ & dry s&4 ,! transportation ( mat]ial by ! w9d is limit$ by ! size ( ! p>ticles to :i* x has access4 ,du/ p>ticles expose m surface to ! w9d relative to _! mass ?an s& gra9s4 ,w9ds :i* are unable to c>ry s& may /ill c>ry du/1 & w9ds :i* are able to %ift s& no m ?an a trivial di/ance may bl[ du/ great di/ances4 ,! common conception ( w9d z a horizontal movem5t ( "s "p ( ! atmosph]e is n altoge!r accurate4 ,e ob/acle aga9/ :i* w9d bl[s causes deflections ( its curr5ts1 & "s ( ^! deflections are upw>d4 ,fur!rmore1 !re are exceptional w9ds1 9 :i* ! v]tical elem5t pr$om9ates4 ,p>ticles ( du/ are (t5 involv$ 9 ^! upw>d curr5ts1 & by !m c>ri$ to great heights1 & 9 ! upp] air are transport$ great di/ances4 ,transportation & deposition ( du/4#c--,! univ]sality ( ! transportation ( du/ by ! w9d is well kn[n4 ,no h\se1 no room1 & sc>cely a draw] c be s tightly clos$ b t du/ ent]s x1 & ! movem5ts ( du/ 9 ! op5 mu/ be mu* m consid]able4 ,! visible du/9ess ( ! atmosph]e 9 dry regions dur+ w9d-/orms is adequate & famili> pro( ( ! effici5cy ( ! w9d z a transport] ( du/4 ,"u special circum/ances1 opportunity is af=d$ = r\gh det]m9ations ( ! di/ance & height to :i* w9d-bl[n du/ is transport$4 ,sn[ tak5 f sn[-fields 9 high m\nta9 regions is f\nd to conta9 a small am\nt ( e>?y matt]4 ,its p>ticles are (t5 f\nd to be 9 "p volcanic1 ev5 :5 ! place :5ce ! sn[ 0 tak5 is scores or ev5 hundr$s ( miles f ! ne>e/ volcano4 ,!re is probably no sn[-field s high1 or s f> f volcanoes1 b t volcanic du/ rea*es x4 ,if ?is be true ( all sn[-fields1 x is probably true ( all l& surfaces4 ,9 ! great ,krakatoa#d eruptions ( #ahhc l>ge quantities ( volcanic a% 7pulv]iz$ lava7 7 project$ to great heights into ! atmosph]e4 ,! co>s] p>ticles soon settl$2 b1 caught by ! curr5ts ( ! upp] atmosph]e1 _m ( ! f9] p>ticles 7 transport$ incr$ible di/ances4 ,?r\gh all _! long j\rney1 ! p>ticles ( du/ 7 gradually settl+ f ! atmosph]e1 b n until ! du/ _h travel$ repeat$ly r\nd ! e>? did its am\nt become s small z to cease to make its influ5ce felt 9 ! hi/oric r$ sunsets :i* x occasion$4#e ,"s ( ?is du/ complet$ ! circuit ( ! e>? 9 #ae days4 ,9 v>i\s p>ts ( ,kansas & ,nebraska#f !re are v consid]able b$s ( volcanic du/1 locally z mu* z #cj feet ?ick1 :i* mu/ h be5 transport$ f volcanic v5ts by ! w9d1 ?\gh !re are no kn[n c5t]s ( volcanic action1 pa/ or pres5t1 )9 "s hundr$s ( miles ( "s ( ! localities :]e ! du/ occurs4 ,^! b$s ( volcanic du/1 s f> f its s\rce1 may s]ve z an illu/ration ( ! importance ( atmosph]ic movem5ts z a geological =ce4 ,volcanic du/ is %ot into ! atmosph]e r ?an pick$ up by x4 ,du/ pick$ up by ! w9d is p]haps transport$ n less widely ?an volcanic du/1 b1 aft] settl+1 its po9t ( orig9 is less readily det]m9$4 ,x w\ld p]haps be an exagg]ation to say t e squ>e mile ( l& surface conta9s p>ticles ( du/ br\ght to x by ! w9d f e o!r squ>e mile1 b su* a /atem5t w\ld probably involve mu* less exagg]ation ?an might at fir/ be suppos$4 ,examples ( ext5sive deposits ( du/ o!r ?an volcanic are also kn[n4 ,9 ,*9a !re is an ext5sive e>?y =mation1 ! loess1 sometimes rea*+ #a1jjj feet 9 ?ickness1 :i* von ,ri*t(5 believes to h be5 deposit$ by ! w9d4#g ,?is conclusion has1 h[ev]1 n pass$ un*all5g$4#h ,! loess ( "s o!r regions has be5 ref]r$ to ! same orig91 & "s ( x is q c]ta9ly eolian4#i ,! transportation ( du/ is important :]ev] /rong w9ds bl[ ov] dry surfaces1 free or ne>ly free ( vegetation1 & compos$ ( e>?y matt]4 ,its effects may be se5 9 su* regions z ! sage-bru% pla9s ( we/]n ,nor? ,am]ica4 ,! roots ( ! sage-bru% hold ! soil imm$iately ab\t !m1 b betwe5 ! clumps ( bru%1 :]e !re is little o!r vegetation1 ! w9d has (t5 bl[n away ! soil to su* an ext5t t ea* clump ( bru% /&s up sev]al in*es1 or ev5 a foot or two1 above its surr\nd+s 7,fig4 #e74 ,su* m\nds are (t5 p>tly due to ! lodgm5t ( du/ ab\t ! bu%es4 ,illu/ration3 ,fig4 #e4--,?is figure %[s ! effect ( sage-bru% or o!r simil> vegetation 9 hold+ s& or e>?1 or 9 caus+ its lodgm5t1 9 dry regions4 ,:]e ! e>?y matt] is moi/1 ! cohesion ( ! p>ticles is great1 & ! w9d _c pick !m up4 ,fur!rmore1 if ! surface is g5]ally moi/1 x is likely to be cov]$ ) vegetation :i* protects x aga9/ ! w9d4 ,b ev5 :]e vegetation is preval5t ! w9d f9ds _m a vuln]able po9t4 ,?us on ! edges ( pla9s or plateaus fac+ abrupt valleys1 ! w9d attacks ! soil f ! side1 & 9 su* situations all e>?y matt] may be /ripp$ f ! und]ly+ rock = consid]able di/ances f ! edge ( ! cliff 7,fig4 #f74 ,?is may be se5 at num]\s po9ts on ! lava plateaus ( ,wa%+ton4 ,illu/ration3 ,fig4 #f4--;,diagram to illu/rate ! way 9 :i* ! w9d sometimes /rips ! soil f ! edge ( a bluff4 ,?is ph5om5on is n r>e 9 ! bas9 ( ! ,columbia ,riv] 9 ,wa%+ton4 ,! pres5ce ( du/ 9 ! upp] atmosph]e dur+ a ra9-/orm is sometimes ! occasion ( ph5om5a :i* are (t5 mis9t]pret$4 ,if !re be abundant du/ 9 ! atmosph]e ?r\gh :i* ra9-drops or sn[flakes fall1 mu* ( x is ga!r$ up by !m1 & ! wat] is !reby r5d]$ turbid & ! sn[ discolor$4 ,"h is to be f\nd ! explanation ( 8mud-ra910 8blood-ra90 7r$ du/71 etc4 ,s9ce du/ is c>ri$ to a consid]able ext5t 9 ! upp] atmosph]e1 its movem5ts & its deposition are little affect$ by ob/acles on ! surface ( ! l&4 ,a build+ or a h$ge c only affect ! lodgm5t ( t "p ( ! atmosph]ic du/ :i* comes 9 contact ) x or is swept into its lee4 ,s9ce mo/ ob/acles on ! surface ( ! solid "p ( ! e>? rea* up b slight di/ances into ! atmosph]e1 ! du/ ( ! great] "p ( ! air settles )\t especial ref]5ce to !m1 & is spread m or less uni=mly ov] ! surface on :i* x falls4 ,illu/ration3 ,fig4 #g4--;,diagram to illu/rate ! effect ( an ob/acle on ! transportation & deposition ( s&4 ,! direction ( ! w9d is indicat$ by ! upp] arr[4 ,! l[] arr[s repres5t ! direction ( eddies 9 ! air occasion$ by ! ob/acle4 ,if ! surface 9 :i* ! ob/acle 0 set 0 orig9ally flat 7dott$ l9e71 ! s& w\ld t5d to be pil$ up on ei!r side at a little di/ance f ! ob/acle1 b m to leew>d4 ,at ! same "t1 depressions w\ld be holl[$ out ne> ! ob/acle itself 7see full l9e74 7,aft] ,corni%47 ,mu* ( ! du/ transport$ by ! w9d is c>ri$ out ov] seas or lakes & falls into !m4 ,by ?is means1 s$im5tation is d\btless go+ on at ! bottom ( ! :ole ocean1 & at ! bottoms ( all lakes4 ,:ile means ( det]m9+ ! am\nt ( du/ bl[n into ! sea are n at h&1 x is safe to say t1 7 su* det]m9ations possible1 ! result1 if /at$ 9 t]ms ( weight1 w\ld be surpris+4 ,transportation & deposition ( s&4--,9 its transportation by ! w9d1 s& is n commonly lift$ f> above ! surface ( ! l&1 & its movem5t is !re=e m g5]ally int]f]$ ) by surface ob/acles ?an is ! movem5t ( du/4 ,a %rub1 a tree1 a f5ce1 a build+1 or ev5 a /one may occasion ! lodgm5t ( s& 9 consid]able quantity1 ?\gh x has little effect on ! lodgm5t ( du/4 ,! effect ( ob/acles is illu/rat$ by ,fig4 #g 7see also ,fig4 #e74 ,if ! ob/acle :i* occasions ! lodgm5t ( s& pres5ts a surface :i* ! w9d _c p5etrate1 su* z a wall1 s& is dropp$ abundantly on its w9dw>d side z well z on ! leew>d2 b if x be p5etrable1 l an op5 f5ce1 ! lodgm5t takes place *iefly on its leew>d side4 ,9 cultivat$ regions cases are kn[n :]e1 9 a few weeks ( dry wea!r1 s& has be5 drift$ into lanes 9 ! lee ( h$ges to ! dep? ( two or ?ree feet1 mak+ !m ne>ly impassable to vehicles4 ,=mation ( dunes4--,9 contra/ ) du/ deposit$ f ! atmosph]e1 w9d-bl[n s& is commonly aggregat$ into m\nds & ridges 9 ! process ( lodgm5t4 ,^! m\nds & ridges are dunes4 ,once a dune is />t$1 x occasions ! fur!r lodgm5t ( s&1 & is a cause ( its own gr[?4 ,dunes sometimes rea* heights ( #bjj or #cjj feet1 b !y are mu* m commonly no m ?an #aj or #bj feet 9 height4 ,on plane surfaces1 !re is a limit 9 height above :i* !y d n rise1 ?\gh ! limit is diff]5t "u diff]5t conditions4 ,! velocity ( w9d at ! bottom ( ! air is n s great z t high] up1 & z a dune is built up1 a level is pres5tly rea*$ :]e ! /rong] upp] w9ds sweep away z mu* s& z is br\ght to ! top4 ,! v ev5 cre/s ( _m dune ridges are probably to be acc\nt$ = 9 ?is way4 ,w9d-bl[n or eolian s&1 n pil$ up 9 heaps or ridges1 is some:at widespread1 b does n con/itute dunes4 ,%apes ( dunes4#aj--;,dunes may assume ! =m ( ridges or ( hillocks4 ,! ridges may be transv]se to ! direction ( ! prevail+ w9d or p>allel ) x4 ,:]e dunes assume ! =m ( hillocks r ?an ridges1 a gr\p ( !m may be elongate 9 a direction p>allel to ! dom9ant w9d1 or at "r angles !reto4 ,! %ape assum$ by a dune or a gr\p ( dunes dep5ds on ! abundance ( ! s&1 ! /r5g? & direction ( ! w9d1 & ! %ape ( ! ob/acle :i* occasions ! lodgm5t4 ,illu/ration3 ,fig4 #h4--;,dune ridges p>allel to ! direction ( ! w9d4 ,s\?we/ "p ( ,india4 ,scale ab\t #c miles to ! in*4 7,corni%47 ,illu/ration3 ,fig4 #i4--;,dune ridges transv]se to ! direction ( ! w9d4 ,scale ab\t #c miles to ! in*4 7,corni%47 ,! incipi5t /ages ( dune =mation are readily se5 9 _m dry1 s&y regions4 ,! dune is likely to />t 9 ! lee ( "s ob/acle1 & to be elongate 9 ! direction ( ! w9d1 especially if ! w9d be /rong relative to ! supply ( s&4 ,?is %ape is p]man5tly pres]v$ if ! prop] relations betwe5 ! supply ( s& & /r5g? & direction ( w9d are pres]v$4 ,9 ! dune region ( ! ,indian des]t#aa ! prevail+ w9ds are alt]nately ! s\?we/ & nor!a/ monsoons1 ! =m] be+ ! /rong]4 ,! supply ( s& comes f ! s\?we/4 ,ne> ! s\?we/ coa/ ! dune ridges are p>allel to ! direction ( ! w9d 7,fig4 #h72 9 ! int]ior1 :]e ! w9ds are less /rong1 ! dunes are transv]se to x 7,fig4 #i72 :ile betwe5 ! di/ricts :]e ^! two types prevail int]m$iate =ms occur4 ,! transv]se dune ridges 7,fig4 #i7 are said to be ! result ( ! lat]al gr[? & erosion ( longitud9al dunes4#ab ,9 regions ( *angeable w9ds ! %ape ( ! dunes is subject to great v>iation4 ,dunes are sometimes cresc5tic1 ! convexity fac+ ! w9d 7,fig4 #aj74 ,illu/ration3 ,fig4 #aj4--;,cresc5tic dunes 9 gr\nd-plan1 ! convexities fac+ ! w9d4 7,bokh>a47 7,wal!r47 ,along coa/s1 dune ridges are (t5 transv]se to ! w9d1 & gr\ps ( dune hillocks are frequ5tly elongate 9 ! same direction4 ,"h ! s\rce ( supply ( ! s& is itself an elongate belt1 (t5 transv]se to ! dom9ant w9d1 & ! result+ dunes (t5 h great l5g? transv]se to ! w9d4 ,:]e ! w9d has /rong ma/]y ov] ! s&1 ! longitud9al t5d5cy is se51 ev5 along coa/s4#ac ,illu/ration3 ,fig4 #aa4--,section ( a dune %[+1 by ! dott$ l9e1 ! /eep leew>d 7bc7 & g5tl] w9dw>d 7ab7 slope4 ,by rev]sal ( ! w9d ! cross-section may be alt]$ to ! =m %[n by ! l9e adc4 7,corni%47 ,illu/ration3 ,fig4 #ab4--;,cross-section ( a dune %[+ ! pr(iles develop$ by sc\r ( ! w9d on bo? flanks4 7,corni%47 ,! %apes ( dunes 9 section1 l ! %apes 9 gr\nd-plan1 dep5d on ! relative /r5g? & con/ancy ( ! w9ds & ! supply ( s&4 ,) con/ant w9ds & abundant drift+ s&1 dunes are /eep on ! lee side 7bc1 ,fig4 #aa71 :]e ! angle ( slope is ! angle ( re/ = ! s&4 ,x r>ely exce$s #bc or #bd4ad ,"u ! same conditions ! w9dw>d slope is relatively g5tle 7ab1 ,fig4 #aa74 ,if ! w9ds be v>iable s t ! w9dw>d slope ( "o p]iod becomes ! leew>d slope ( ano!r1 & vice v]sa1 ?is =m is n pres]v$4 ,?us1 by rev]sal ( ! w9d1 ! section abc1 ,fig4 #aa1 may be *ang$ to adc4 ,if ! w9ds & ! supply ( s& be equal1 on ! av]age1 f opposite directions1 ! slopes %\ld1 on ! av]age1 be equal1 ?\gh p]haps unequal aft] any p>ticul> /orm4 ,! /eep slopes ( new-made dunes are lo/ aft] ! s& has ceas$ to be bl[n4 ,at "s po9ts :]e ! w9ds erode 7sc\r7 m ?an !y deposit1 new pr(iles are develop$ 7,figs4 #ab & #ac74 ,! erosion pr(iles may be v irregul> if ! dunes are p>tially cov]$ ) vegetation4 ,! effect ( vegetation 9 re/ra9+ w9d erosion is %[n 9 ,fig4 #ad1 :]e plants h pres]v$ a remnant ( a dune4 ,! topographic map4--,s9ce dunes z well z o!r topographic features are conv5i5tly repres5t$ on cont\r maps1 & s9ce su* maps w be us$ frequ5tly 9 ! foll[+ pages1 a g5]al explanation ( !m is "h introduc$4 8,! features repres5t$ on ! topographic map are ( ?ree di/9ct k9ds3 7#a7 inequalities ( surface1 call$ relief1 z pla9s1 plateaus1 valleys1 hills1 & m\nta9s2 7#b7 di/ribution ( wat]1 call$ dra9age1 z /reams1 lakes1 & swamps2 7#c7 ! works ( man1 call$ culture1 z roads1 railroads1 b\nd>ies1 villages1 & cities4 ,illu/ration3 ,fig4 #ac4--;,diagram %[+ ! outl9e ( dunes 9 process ( de/ruction4 ,sev5 ,mile ,bea*1 ,n4 ,j4 7,n4 ,j4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #ad4--;,illu/rates ! protective effect ( vegetation aga9/ w9d erosion4 ,dune ,p>k1 ,ind4 7,c[les7 ,relief4--,all elevations are measur$ f mean sea-level4 ,! heights ( _m po9ts are accurately det]m9$1 & ^? :i* are mo/ important are giv5 on ! map 9 figures4 ,x is desirable1 h[ev]1 to give ! elevation ( all p>ts ( ! area mapp$1 to del9eate ! horizontal outl9e1 or cont\r1 ( all slopes1 & to indicate _! grade or degree ( /eepness4 ,?is is done by l9es connect+ po9ts ( equal elevation above mean sea-level1 ! l9es be+ drawn at regul> v]tical int]vals4 ,^! l9es are call$ cont\rs1 & ! uni=m v]tical space betwe5 ea* two cont\rs is call$ ! cont\r int]val4 ,on ! maps ( ! ,unit$ ,/ates ,geological ,survey ! cont\rs & elevations are pr9t$ 9 br[n 7see ,plate ,,ii74 ,illu/ration3 ,fig4 #ae4--,sket* & map ( ! same area to illu/rate ! repres5tation ( topography by means ( cont\r l9es 7,u4 ,s4 ,geol4 ,surv47 ,! mann] 9 :i* cont\rs express elevation1 =m1 & grade is %[n 9 ! foll[+ sket* & correspond+ cont\r map1 ,fig4 #ae4 ,! sket* repres5ts a riv] valley betwe5 two hills4 ,9 ! =egr\nd is ! sea1 ) a bay :i* is p>tly clos$ by a hook$ s& b>4 ,on ea* side ( ! valley is a t]race4 ,f ! t]race on ! "r a hill rises gradually1 :ile f t on ! left ! gr\nd asc5ds /eeply 9 a precipice4 ,contra/$ ) ?is precipice is ! g5tle desc5t ( ! slope at ! left4 ,9 ! map ea* ( ^! features is indicat$1 directly b5ea? its position 9 ! sket*1 by cont\rs4 ,! foll[+ explanation may make cle>] ! mann] 9 :i* cont\rs del9eate elevation1 =m1 & grade3 #a4 ,a cont\r indicates approximately a c]ta9 height above sea-level4 ,9 ?is illu/ration ! cont\r int]val is #ej feet2 !re=e ! cont\rs are drawn at #ej1 #ajj1 #aej1 #bjj feet1 & s on1 above sea-level4 ,along ! cont\r at #bej feet lie all po9ts ( ! surface #bej feet above sea2 & simil>ly ) any o!r cont\r4 ,9 ! space betwe5 any two cont\rs are f\nd all elevations above ! l[] & bel[ ! high] cont\r4 ,?us ! cont\r at #aej feet falls j bel[ ! edge ( ! t]race1 :ile t at #bjj feet lies above ! t]race2 !re=e all po9ts on ! t]race are %[n to be m ?an #aej b less ?an #bjj feet above sea4 ,! summit ( ! high] hill is /at$ to be #fgj feet above sea2 accord+ly ! cont\r at #fej feet surr\nds x4 ,9 ?is illu/ration ne>ly all ! cont\rs are numb]$4 ,:]e ?is is n possible1 c]ta9 cont\rs--say e fif? "o--are acc5tuat$ & numb]$2 ! heights ( o!rs may !n be asc]ta9$ by c\nt+ up or d[n f a numb]$ cont\r4 #b4 ,cont\rs def9e ! =ms ( slopes4 ,s9ce cont\rs are cont9u\s horizontal l9es con=m+ to ! surface ( ! gr\nd1 !y w9d smoo?ly ab\t smoo? surfaces1 rec$e into all rentrant angles ( rav9es1 & project 9 pass+ ab\t prom95ces4 ,! relations ( cont\r curves & angles to =ms ( ! l&scape c be trac$ 9 ! map & sket*4 #c4 ,cont\rs %[ ! approximate grade ( any slope4 ,! v]tical space betwe5 two cont\rs is ! same1 :e!r !y lie along a cliff or on a g5tle slope2 b to rise a giv5 height on a g5tle slope "o mu/ g f>!r ?an on a /eep slope1 & !re=e cont\rs are f> ap>t on g5tle slopes & ne> toge!r on /eep ones4 ,= a flat or g5tly undulat+ c\ntry a small cont\r int]val is us$2 = a /eep or m\nta9\s c\ntry a l>ge int]val is necess>y4 ,! smalle/ int]val us$ on ! atlas %eets ( ! ,geological ,survey is #e feet4 ,?is is us$ = regions l ! ,mississippi delta & ! ,dismal ,swamp4 ,9 mapp+ great m\nta9 masses1 l ^? 9 ,colorado1 ! int]val may be #bej feet4 ,= int]m$iate relief cont\r int]vals ( #aj1 #bj1 #be1 #ej1 & #ajj feet are us$4 ,dra9age4--,wat]c\rses are indicat$ by blue l9es4 ,if ! /reams fl[ ! ye> r\nd ! l9e is drawn unbrok51 b if ! *annel is dry a "p ( ! ye> ! l9e is brok5 or dott$4 ,:]e a /ream s9ks & reappe>s at ! surface1 ! suppos$ und]gr\nd c\rse is %[n by a brok5 blue l9e4 ,lakes1 m>%es1 & o!r bodies ( wat] are also %[n 9 blue1 by appropriate conv5tional signs4 ,culture4--,! works ( man1 su* z road1 railroads1 & t[ns1 toge!r ) b\nd>ies ( t[n%ips1 c\nties & /ates1 & artificial details1 are pr9t$ 9 black40#ae ,topography ( dune areas4--,f :at has be5 said1 x is cle> t ! topography ( dune regions may v>y widely1 b x is always di/9ctive4 ,:]e ! dunes take ! =m ( ridges 7,fig4 #a1 ,pl4 ,,ii71 ! ridges are (t5 ( ess5tially uni=m height & wid? = consid]able di/ances4 ,if !re are p>allel ridges1 !y are (t5 sep>at$ by tr\gh-l depressions4 ,:]e dunes assume ! =m ( hillocks 7,figs4 #b & #c1 ,pl4 ,,ii71 r ?an ridges1 ! topography is ev5 m di/9ctive4 ,9 "s regions1 depressions 7bas9s7 are associat$ ) ! dune hillocks4 ,occasionally !y are h>dly less notable ?an ! dunes !mselves4 ,a some:at simil> association ( hillocks & bas9s is locally develop$ by o!r means1 b dunes are made up ( s& & usually ( s& only1 :ile ! composition ( simil>ly %ap$ hillocks & depressions %ap$ by o!r ag5cies is notably diff]5t4 ,9 ,fig4 #a1 ,plate ,,ii 7,five ,mile ,bea*1 #h miles nor!a/ ( ,cape ,may1 ,n4 ,j471 ! cont\r int]val is #aj feet4 ,!re is "h b "o cont\r l9e 7! #aj-;foot cont\r71 ?\gh ?is appe>s 9 sev]al places4 ,s9ce ?is l9e connects places #aj feet above sea-level1 all places betwe5 x & ! sea 7or m>%7 are less ?an #aj feet above ! wat]1 :ile all places )9 ! l9es h an elevation ( m ?an #aj feet4 ,none ( !m rea*es an elevation ( #bj feet1 s9ce a #bj-;foot cont\r does n appe>4 ,x w be se5 t "s ( ! elevations 9 ,fig4 #a are elongate1 :ile o!rs h ! =m ( m\nds4 ,fig4 #b 7,pl4 ,,ii7 %[s dune topography along ! ,arkansas ,riv] 9 ,kansas 7ne> ,l>n$72 ,fig4 #d1 dune topography 9 ,nebraska 7,lat4 #db1 ,long4 #ajc71 n 9 imm$iate association ) a valley or %ore2 & ,fig4 #c %[s irregul> ridge-l dunes at ! head ( ,lake ,mi*igan4 ,9 ,fig4 #b ! cont\r int]val is #bj feet4 ,all ! small hillocks s\!a/ ( ! riv] are dunes4 ,"s ( !m are repres5t$ by "o cont\r & "s by two4 ,! altitude ( ! region is consid]able1 ! heavy cont\r repres5t+ an elevation ( #bajj feet2 b ! dunes !mselves are r>ely m ?an #bj feet above _! surr\nd+s4 ,9 ,fig4 #d1 :]e ! cont\r int]val is also #bj feet1 !re are1 besides ! num]\s hillocks1 sev]al depressions 7bas9s74 ,^! are repres5t$ by ha*ures inside ! cont\r l9es4 ,9 "s cases !re are int]mitt5t lakes 7blue7 9 ! depressions4 ,! heavy cont\r at ,spr+ ,lakes 9 ?is figure is ! cont\r ( #dcjj feet4 ,!re are two depression cont\rs 7#dbhj & #dbfj7 bel[ x4 ,! bottom ( ! depression is !re=e l[] ?an #dbfj1 b n s l[ z #dbdj4 ,9 ,fig4 #c ! cont\r int]val is #aj feet1 & ! dune ridges nor? ( ,mill] are m ?an #ej feet high4 ,! dune ridges "h h help$ to det]m9e ! position ( ?is bran* ( ! ,calumet ,riv]1 & h block$ its =m] outlet4 ,! pres5t dra9age is to ! we/w>d4 ,migration ( dunes4--,by ! cont9ual transf] ( s& f its w9dw>d to its leew>d side1 a dune may be mov$ f "o place to ano!r1 ?\gh cont9u+ to be made up1 9 l>ge "p1 ( ! same s&4 ,9 _! migration dunes sometimes invade f]tile l&s1 caus+ s great loss t means are devis$ = /opp+ !m4 ,! simple/ me?od 7employ$ 9 ,france & ,holl&7 is to help vegetation to get a foo?old 9 ! s&4 ,! effect ( ! vegetation is to p9 ! s& d[n4 ,z a dune ridge along a coa/ travels inl&1 ano!r may be =m$ beh9d x4 ,successions ( dune ridges are ?us sometimes =m$4 ,illu/ration3 ,fig4 #af4--;,diagram illu/rat+ ! migration ( dunes on ! ,kuris*e ,nehrung4 7,cr$n]47 ,a rem>kable in/ance ( ! migration ( a s& dune is record$ on ! ,kuris*e ,nehrung on ! nor? coa/ ( ,g]many4 ,! ,nehrung consi/s ( a long n>r[ neck ( l& compos$ ( s&1 ly+ (f ! ma9 coa/4 ,at ! beg9n+ ( ?is c5tury !re 0 a notable dune ridge on "o side4 ,s9ce t "t x has migrat$ a consid]able di/ance1 & 9 its migration x has be5 br\ght into ! relation%ips illu/rat$ 9 ! accompany+ diagrams 7,fig4 #af74 ,9 #ahjj ! dune ridge 0 on "o side ( a *ur*1 :i* 0 !n 9 use4 ,9 #ahci ! ridge _h be5 s f> %ift$ to ! leew>d z to completely bury ! *ur*1 & 9 #ahfi1 its migration _h progress$ s f> z to aga9 discov] ! build+4#af ,illu/ration3 ,fig4 #ag4--,migration ( dunes into a timb]$ region4 ,dune ,p>k1 ,ind4 ,head ( ,lake ,mi*igan4 7,mey]s47 ,:5 dunes migrate into a timb]$ region !y bury & kill ! trees 7,fig4 #ag74 ,9 "o in/ance on ! coa/ ( ,prussia a tall p9e =e/1 cov]+ hundr$s ( acres1 0 de/roy$ dur+ ! brief p]iod betwe5 #ahjd & #ahbg4ag ,at "s po9ts 9 ,new ,j]sey or*>ds h be5 s f> buri$ )9 ! lifetime ( _! own]s t only ! tops ( ! highe/ trees are expos$4 ,trees & o!r objects once buri$ may be aga9 discov]$ by f>!r migration ( ! s& 7,figs4 #ah & #ai74ah ,illu/ration3 ,fig4 #ah4--;,a resurrect$ =e/4 ,! dune s& aft] bury+ & kill+ ! timb] has be5 %ift$ beyond x4 ,dune ,p>k4 ,ind4 7,mey]s47 ,eolian s&1 n aggregat$ into di/9ct dunes1 is (t5 de/ructive4 ,ev5 valleys & cities are sometimes buri$ by x4 ,drift+ s&s _h s completely buri$ ,n9eveh two c5turies aft] its de/ruction t its site 0 unkn[n4 ,di/ribution ( dunes4--,dunes are likely to be develop$ :]ev] dry s& is expos$ to ! w9d4 ,_! favorite situations are ! dry & s&y %ores ( lakes & seas1 s&y valleys1 & arid s&y pla9s4 ,along coa/s1 dunes are likely to be ext5sively develop$ only :]e ! prevail+ w9ds are on %ore4 ,?us ab\t ,lake ,mi*igan1 :]e ! prevail+ w9ds are f ! we/1 dunes are abundant & l>ge on ! ea/ %ore1 & b few & small on ! we/4 ,9 %all[ wat]1 %ore curr5ts & /orm waves (t5 build up a reef ( s& a little above ! normal level ( ! wat]4 ,:5 ! waves subside1 ! s& dries & ! w9d heaps x up into dunes4 ,?is sequ5ce ( ev5ts is 9 progress at _m po9ts on ! ,atlantic ,coa/4 ,s&y ,hook1 ,new ,j]sey1 & ! 8bea*es0 f>!r s\? />t$ z b>ri] ridges4 ,:5 ! waves _h built !m above normal wat]-level1 ! w9d re-work$ ! s&1 pil+ x up into m\nds & hillocks 7,fig4 #a1 ,pl4 ,,ii74 ,su* dune belts a little (f %ore are sometimes turn$ to good acc\nt4 ,!y are usually sep>at$ f ! ma9l& by a %all[ lagoon4 ,:]e l& is valuable1 ! lagoon is sometimes fill$ 91 mak+ new l&1 ?us anticipat+ ! result :i* nature w\ld a*ieve m sl[ly4 ,?is has be5 done at "s po9ts on ! we/]n coa/ ( ,europe4 ,illu/ration3 ,fig4 #ai4--,migration ( dune s& expos+ bones 9 a cemet]y4 ,hatt]as ,isl&1 ,n4 ,c4 7,colli] ,cobb47 ,dunes are likely to occur along /ream valleys 7,fig4 #b1 ,pl4 ,,ii71 if _! bottoms or slopes are ( s&1 & n cov]$ by vegetation4 ,dunes along valleys are usually on ! side t[>d :i* ! prevail+ w9ds bl[4 ,?us !y are m common on ! ea/ side ( ! ,mississippi ?an on ! we/4 ,dunes may be =m$ 9 ! valley bottoms1 b ! s& is (t5 bl[n up out ( ! valley & lodg$ on ! bluffs above4 ,ap>t f ^! special classes ( situations1 any s&y region ! surface ( :i* is dry is likely to h its surface mat]ial %ift$ by ! w9d & pil$ up into dune ridges or hillocks 7,fig4 #d1 ,pl4 ,,ii74 ,dunes probably rea* _! greate/ developm5t 9 ! ,sah>a1 :]e "s ( !m take ! =m ( hillocks1 & "s ! =m ( ridges4 ,travel]s 9 t region report t dune ridges are sometimes enc\nt]$ ! faces ( :i* are s high & /eep z to be difficult ( asc5t1 & t p>ties h be5 oblig$ to travel miles along _! bases be=e f9d+ a break :]e cross+ 0 practicable4 ,illu/ration3 ,fig4 #bj4--,w9d-ripples4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,w9d-ripples4--,! surface ( ! dry s& ov] :i* ! w9d has bl[n = a few h\rs is likely to be m>k$ ) ripples 7,fig4 #bj7 simil> to ^? made on a s&y bottom b5ea? %all[ wat]1 "u ! influ5ce ( waves4 ,l ripple m>ks made by ! wat]1 w9d-ripples h "o side 7! lee7 /eep] ?an ! o!r4 ,:ile ! ripples are1 z a rule1 b a fraction ( an in* high1 !y ?r[ mu* light on ! orig9 ( ! great dune ridges4 ,if ! ripples be wat*$ closely dur+ ! progress ( a w9d-/orm1 !y are f\nd gradually to %ift _! position4 ,s& is bl[n up ! g5tl] w9dw>d slope to ! cre/ ( ! ridge & falls d[n on ! o!r side4 ,! mom5t x falls bel[ ! cre/ ( ! ridge to leew>d1 x is protect$ aga9/ ! w9d1 & is likely to lodge4 ,we> on ! w9dw>d side is ab\t equal to deposition on ! leew>d1 & ! result is ! ord]ly progression ( ! ripples 9 ! direction 9 :i* ! w9d is bl[+1 j z 9 ! case ( dune ridges4 ,abrasion by ! w9d4--,:ile ! effect ( ! w9d on s&y & du/y surfaces may be consid]able1 its effect on solid rock is relatively slight & accompli%$1 n by its own impact1 b by t ( ! mat]ial x c>ries4 ,! effect ( bl[n s& on rock surfaces ov] & aga9/ :i* x is driv5 is p]haps be/ und]/ood by recall+ ! effects ( artificial s&-bla/s1 by means ( :i* glass is et*$4 ,9 a region :]e s& is bl[+1 expos$ surfaces ( rock suff] f a multitude ( bl[s /ruck by ! s& gra9s 9 transit4 ,! result is t su* rock surfaces are worn1 & worn 9 a way peculi> to ! ag5cy accompli%+ ! "w4 ,if ! rock be made up ( lam9 :i* are ( unequal h>dness1 ! bl[n s& digs out ! s(t] ones1 leav+ ! h>d] project+ z ridges betwe5 !m4 ,adjac5t masses ( h>d] & s(t] rock ( :atev] ?ickness are simil>ly affect$4 ,! sculptur+ ?us effect$ on project+ masses ( rock is (t5 picturesque & /rik+ 7,figs4 #ba & #bb71 & is mo/ common 9 arid regions4 ,details ( w9d-c>v+ are %[n 9 ,fig4 #bc4 ,illu/ration3 ,fig4 #ba4--,w9d-c>v$ rock4 7,gre547 ,illu/ration3 ,,plate ,,ii4 ,fig4 #a4 ,,new ,,j]sey4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,kansas4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #c4 ,,indiana4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #d4 ,,nebraska4 ,u4 ,s4 ,geol4 ,surv4 ,s& drift$ ov] loose /ones ly+ on ! surface (t5 develops flat or flatti% faces or facets on !m4 ,^! facets are likely to be ?ree 9 numb]1 & ! expos$ portion ( ! /one is likely to develop a sort ( pyramidal %ape1 ! ?ree flatti% surfaces be+ mutually limit$ by tol]ably well-def9$ l9es 7,fig4 #bd74 ,?us arise ! ?ree-facet$ /ones 7,dreikant] ( ! ,g]mans7 commonly se5 :]e s&s h be5 long 9 movem5t4 ,illu/ration3 ,fig4 #bb4--,w9d-c>v$ hillock ( cross-b$d$ s&/one4 ,miss\ri ,riv]1 ,montana4 7,calh\n1 ,u4 ,s4 ,g4 ,s47 ,n only does ! drift+ s& we> ! surface ov] :i* x passes & aga9/ :i* x /rikes1 b ! gra9s !mselves are worn 9 ! process4 ,!y are liable to be brok5 z !y /rike rock surfaces1 & !y are likely to /rike "o ano!r 9 ! atmosph]e4 ,9 bo? cases !y are subject to we>1 & s to r$uction to a f9] & f9] /ate4 ,! erosion accompli%$ by ! w9d is !re=e ( v>i\s sorts4 ,! impact ( ! w9d itself picks up ! f9e mat]ials :i* are already loos5$1 ?us we>+ d[n ! surface f :i* !y are remov$2 ! mat]ials pick$ up we> ! rock surfaces aga9/ :i* !y are bl[n1 & ! transport$ mat]ials !mselves suff] r$uction 9 transit4 ,effects ( w9d on plants4--,ano!r effect ( w9d "w is se5 9 ! uproot+ ( trees 7,fig4 #be74 ,! uproot+ di/urbs ! surface 9 su* a way z to make loose e>? m readily accessible to w9d & wat]4 ,! uproot+ ( trees on /eep slopes (t5 causes ! desc5t ( consid]able quantities ( loose rock & soil4 ,aga91 organisms ( v>i\s sorts 7c]ta9 types ( se$s1 g]ms1 etc471 z well z du/ & s&1 are ext5sively transport$ by ! w9d4 ,:ile ?is is important biologically its geological effects are remote4 ,illu/ration3 ,fig4 #bc4--;,figure %[+ details ( w9d-c>v+ on rock surface 7rhyolite74 ,mono ,valley1 ,cali=nia4 ,illu/ration3 ,fig4 #bd4--,w9d-worn /ones 7,dreikant]74 ,illu/ration3 ,fig4 #be4--,%[s ! di/urbance ( surface e>? & rocks by upturn+ ( trees4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,indirect effects ( ! w9d4--,o!r dynamic processes are call$ into be+ or /imulat$ by ! atmosph]e4 ,w9ds g5]ate bo? waves & curr5ts1 & bo? are effective ag5ts 9 geological "w4 ,! results ( _! activities are discuss$ else:]e4 ,,ii4 ,! ,*emical ,"w ( ! ,atmosph]e4 ,! *emical "w ( ! atmosph]e 7includ+ solution & precipitation f solution7 is pr9cipally accompli%$ 9 connection ) wat]1 a dry atmosph]e hav+ relatively little direct *emical effect on rock or soils4 ,precipitation f solution4--,! wat] 9 ! soil is con/antly evaporat+4 ,su* sub/ances z x conta9s 9 solution are deposit$ :]e ! wat] evaporates1 & :]e evaporation is long cont9u$ )\t re-solution ( ! sub/ances deposit$1 ! surface becomes coat$ ) an effloresc5ce ( m9]al matt]4 ,conspicu\s examples are f\nd 9 ! alkali pla9s ( c]ta9 areas 9 ! we/]n "p ( ! ,unit$ ,/ates4 ,s9ce ! alkal9e effloresc5ce is ! result ( evaporation x is connect$ ) ! atmosph]e1 b ! mat]ial ( ! effloresc5ce 0 br\ght to its pres5t position by wat]4 ,! pr9ciple involv$ is illu/rat$ by ! :ite effloresc5ce :i* frequ5tly appe>s on brick walls dur+ ! dry days :i* foll[ a dr5*+ ra94 ,! wat] p5etrates ! brick & mort> & dissolves some?+ ( _! sub/ance1 & :5 x is evaporat$ f ! surface ! mat]ial 9 solution is left beh9d4 ,9 arid regions ! deposition ( sub/ances o!r ?an alkali is common4 ,! p]colat+ wat]s dissolve :atev] is soluble1 & :5 !y evaporate _! m9]al cont5t is left4 ,! pebbles & /ones ( ! arid pla9s h 9 _m places become heavily coat$ ) m9]al matt] deposit$ 9 ?is way1 & n infrequ5tly cem5t$ into conglom]ate4 ,"o ( ! commone/ m9]al sub/ances f\nd 9 su* situations is lime c>bonate4 ,9 "s cases x 0 d\btless d]iv$ by solution f lime/one b$s b5ea? ! surface1 b ?is is n always ! case4 ,x (t5 encru/s ! bits ( lava on lava pla9s :]e x c h>dly h be5 d]iv$ f lime/one4 ,! faces ( cliffs ( granite or gneiss1 hundr$s & ev5 ?\s&s ( feet above all o!r sorts ( rock1#ai are sometimes spott$ ) pat*es ( lime c>bonate4 ,9 ! fir/ case ! lime c>bonate 0 d]iv$ by *emical *ange f ! lava1 & 9 ! second1 f ! granite or gneiss 7see ,c>bonation bel[71 b its pres5t position is ! result ( evaporation4 ,oxidation4--,9 ! pres5ce ( moi/ure ! oxyg5 ( ! air ent]s into comb9ation ) v>i\s elem5ts ( ! soil & rocks4 ,?is is oxidation4 ,no o!r common m9]al sub/ance %[s ! results ( oxidation s quickly & s di/9ctly z iron4 ,! oxidiz$ portion is loose & friable1 & a mass ( iron expos$ to a moi/ atmosph]e w ultimately crumble away4 ,?is *ange is comp>able to o!r less obvi\s *anges tak+ place 9 _m m9]als at & bel[ ! surface4 ,oxidation g5]ally involves ! dis9tegration ( ! rock conc]n$4 ,its effects 9 ?is direction w be ref]r$ to 9 o!r connections4 ,c>bonation4--,! production ( lime c>bonate f rock conta9+ calcium comp\nds1 b n 9 ! =m ( c>bonates1 is kn[n z c>bonation1 & is "o ( ! important *emical *anges effect$ by ! c>bon dioxide ( ! atmosph]e 9 cop]ation ) wat]4 ,9 ! process ( c>bonation ! orig9al m9]als ( complex composition are decompos$ & simpl] ones usually =m$4 ,volumetric *anges are involv$1 :i* (t5 lead to ! disruption ( ! rock 7see ,gr\nd wat]74 ,fur!rmore1 c>bonates are among ! m soluble m9]als1 & _! production !re=e br+s "s ( ! rock mat]ials into a soluble condition1 & _! extraction ?r\gh solution t5ds /ill fur!r to dis9tegrate ! rock4 ,! c>bonation ( cry/all9e rocks is !re=e a dis9tegrat+ process1 & w be consid]$ fur!r 9 its _m concrete applications4 ,o!r *emical *anges4--,a ?ird *emical process :i* (t5 accompanies oxidation & c>bonation is hydration4 ,?is is effect$ by wat] r ?an by air1 & w be consid]$ 9 t connection4 ,9 g5]al x leads to ! dis9tegration ( ! m9]als & rocks affect$4 ,! *emical effects ( nitric acid1 etc41 develop$ ?r\gh ! ag5cy ( atmosph]ic electricity1 & ! correspond+ effects ( ! gases & vapors :i* issue f volcanoes1 _m ( !m *emically active1 are to be m5tion$ 9 ?is connection4 ,conditions favorable = *emical *anges4--,conditions are n ev]y:]e equally favorable = ! *emical "w ( ! atmosph]e4 ,9 g5]al1 high temp]atures facilitate *emical action1 &1 o!r ?+s be+ equal1 rocks are m readily decompos$ by atmosph]ic action 9 w>m ?an 9 cold regions4 ,*emical activity is probably great] :]e ! climate is cont9u\sly w>m ?an :]e !re are great *anges ( temp]ature4 ,*anges ( temp]ature1 on ! o!r h&1 t5d to disrupt rock1 & ?us increase ! am\nt ( surface expos$ to *emical *ange4 ,s9ce ne>ly all ! *emical *anges work$ by ! atmosph]e on ! rocks are increas$ by ! pres5ce ( moi/ure1 ! *emical activity ( ! atmosph]e is great] 9 moi/ ?an 9 dry regions4 ,b4 ,,! ,,atmosph]e ,,z ,a ,,condition+ ,,ag5cy4 ,! mo/ obvi\s me*anical "w ( ! atmosph]e is effect$ by ! w9d1 b me*anical results ( great importance1 condition$ by ! atmosph]e1 are also effect$ :5 ! air is /ill4 ,i4 ,temp]ature ,effects4 ,:5 ! sun %9es on b>e rock its surface is heat$ & exp&$1 & ! exp&$ p>ticles cr[d "o ano!r ) great =ce4 ,s9ce rock is a poor conductor ( heat its surface is heat$ & exp&$ notably m ?an p>ts b5ea? ! surface4 ,x foll[s t /ra9s are set up betwe5 ! exp&$ out] portion & ! cool] & less exp&$ p>ts )94 ,9 ! cool+ ( ! same rock mass x is ! out]mo/ portion :i* cools fir/ & fa/e/1 &1 contract+ z x cools1 /ra9s are aga9 set up betwe5 ! out] "p1 :i* is cool$ m1 & ! inn] "p1 :i* is cool$ less4 ,! result may be illu/rat$ by ! effect ( cold wat] on hot glass1 or ( hot wat] on cold glass4 ,9 ei!r case ! fracture is ! result ( ! sudd5 & consid]able diff]5tial expansion or contraction4 ,s9ce ! heat+ & cool+ ( rock are mu* sl[] ?an ! heat+ & cool+ ( glass "u ! conditions m5tion$1 ! ruptur+ effects are less conspicu\s1 b none ! less real4 ,! actual effects ( temp]ature *anges are illu/rat$ by famili> ph5om5a4 ,! surface portions ( b[ld]s expos$ to ! sun are frequ5tly se5 to be %ell+ (f 7,fig4 #bf74 ,! loos5$ conc5tric %ells may be a fraction ( an in*1 or sometimes ev5 sev]al in*es 9 ?ickness4 ,?is process ( exfoliation affects n only b[ld]s1 b b>e rock surfaces :]ev] expos$ to ! sun 7,figs4 #bg1 #bh74 ,x is (t5 conspicu\s on ! faces ( cliffs4 ,illu/ration3 ,fig4 #bf4--;,exfoliation4 ,a b[ld] ( wea!r+1 ! rock be+ granite4 ,wi*ita ,m\nta9s1 ,oklahoma4 ,illu/ration3 ,fig4 #bg4--;,a wea!r$ summit ( granite 9 ! ,wi*ita ,m\nta9s4 ,oklahoma4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,sev]al conditions1 "s ( :i* are connect$ ) ! atmosph]e & "s ) ! rock1 det]m9e ! effici5cy ( ?is process4 ,s9ce ! break+ ( ! rock results f ! expansion & contraction due to its *anges ( temp]ature1 x foll[s t1 o!r ?+s be+ equal1 ! great] ! *ange1 ! great] ! break+2 b ! sudd5ness ( ! temp]ature *ange is ev5 m important ?an its am\nt4 ,x foll[s t great daily1 r ?an great annual1 *anges ( temp]ature#bj favor rock-break+1 ?\gh ) *anges ( a giv5 frequ5cy _! effectiv5ess is great] ! great] _! range4 ,a p>tial exception to ?is g5]alization %\ld be not$4 ,if abundant moi/ure is pres5t 9 ! pores & cracks ( ! rock a *ange ( temp]ature f #de to #ce 7,fahr47 might be f> less effective 9 break+ ! rock ?an a *ange f #ce to #be 9 ! same "t1 = 9 ! latt] case ! sudd5 & v consid]able expansion 7ab\t "o-t5?7 :i* wat] und]goes on freez+ is br\ght into play4 ,?is may be call$ ! w$ge-"w ( ice4 ,! daily range ( temp]ature is influ5c$ especially by latitude1 altitude1 & humidity4 ,o!r ?+s be+ equal1 ! greate/ daily ranges ( temp]ature occur 9 high-temp]ate latitudes1 ?\gh to ?is g5]al /atem5t !re are local exceptions1 dep5d+ on o!r conditions4 ,high altitudes favor great daily ranges ( temp]ature1 s f> z ! rock surface is conc]n$ 7see ,figs4 #bi1 #cj71 = ?\gh ! rock becomes heat$ dur+ ! sunny day1 ! ?9ness & dryness ( ! atmosph]e all[ its heat to radiate rapidly at night4 ,"h1 too1 ! daily range ( temp]ature is likely to br+ ! w$ge-"w ( ice into play4 ,s9ce ! s\? side ( a m\nta9 79 ! nor!rn hemisph]e7 is heat$ m ?an ! nor?1 x is subject to ! great] daily range ( temp]ature1 & ! rock on ?is side suff]s ! great] disruption4 ,simil>ly1 rock surfaces on :i* ! sun %9es daily are subject to great] disruption ?an ^? mu* %ield$ by cl\ds4 ,isolat$ peaks1 because ( _! great] exposure1 are subject to r great] daily ranges ( temp]ature ?an plateaus ( ! same elevation4 ,illu/ration3 ,fig4 #bh4--;,exfoliation on a m\nta9 slope4 ,mt4 ,/>r-,k+ 7,cal47 f ! nor?4 ,! daily range ( temp]ature is also influ5c$ by humidity4 ,because ( ! effect ( wat] vapor 9 ! atmosph]e on insolation & radiation1 a rock surface becomes hott] 9 ! day & cool] at night b5ea? a dry atmosph]e ?an b5ea? a moi/ "o4 ,aridity !re=e favors ! disruption ( rock by *ang+ temp]atures4 ,turn+ f ! conditions ( ! atmosph]e :i* affect ! disruption ( rock to ! conditions ( ! rock :i* influ5ce ! same process1 sev]al po9ts are to be not$4 ,9 ! fir/ place1 ! disrupt+ effects ( *anges ( temp]ature are slight or nil :]e ! solid rock is protect$ by soil1 clay1 s&1 gravel1 sn[1 or o!r incoh]5t mat]ial4 ,if ! con/itu5t p>ts ( ! loose mat]ial are co>se1 l b[ld]s1 _! surfaces are affect$ l ^? ( l>g] bodies ( rock4 ,! color ( rock1 its texture & its composition1 also influ5ce its range ( daily temp]ature by influ5c+ absorption & conduction4 ,d>k-color$ rocks absorb m heat ?an light-color$ ones1 & compact rocks are bett] conductors ?an por\s ones4 ,great absorption & sl[ conduction favor disruption4 ,a giv5 range ( temp]ature is unequally effective on rocks ( diff]5t m9]al composition4 ,9 g5]al cry/all9e rocks 7igne\s & metamorphic7 are m subject to disruption by ?is means ?an s$im5t>y rocks1 p>tly because !y are m compact1 b especially because !y are made up ( aggregates ( cry/als ( diff]5t m9]als :i*1 "u *anges ( temp]ature1 exp& & contract at diff]5t rates1 :ile ! common s$im5t>y rocks are made up l>gely ( num]\s p>ticles ( "o m9]al4 ,illu/ration3 ,fig4 #bi4--,top ( ,not* ,peak1 ,bighorn ,m\nta9s1 ,wyo4 ,%[s ! ?or\ghly brok5 "* ( ! rock on ! summit1 ! abs5ce ( soil1 vegetation1 etc4 7,kmmel47 ,illu/ration3 ,fig4 #cj4--;,a detail f ,fig4 #bi %[+ ! size ( ! rock blocks4 7,kmmel47 ,illu/ration3 ,fig4 #ca4--,peak nor? ( ,ke>s>ge ,pass1 ! ,si]ras4 ,%[s ! way 9 :i* s]rate peaks break up into angul> blocks4 ,! freez+ ( wat] 9 ! pores ( rock is effective 9 disrupt+ !m only :5 ! pores are ess5tially full at ! "t ( freez+4 ,o!rwise !re is room = ! expansion att5d+ ! freez+4 ,if ! pores ( ! rock are l>ge1 ! expansion on freez+ may =ce out suffici5t wat] to balance ! increase ( volume1 ev5 ?\gh ! rock 0 completely saturat$4 ,if ! pores be v small ! wat] passes out less readily1 & if ! rock is saturat$1 freez+ is m likely to be att5d$ ) disruption4#ba ,9 view ( ^! consid]ations ! break+ ( rock by *anges ( temp]ature %\ld be greate/ on ! b>e slopes ( isolat$ elevations ( cry/all9e rock1 :]e ! temp]ature conditions ( temp]ate latitudes prevail1 & :]e ! atmosph]e is relatively free f moi/ure4 ,all ^! conditions are n (t5 f\nd 9 "o place1 b ! disrupt+ effects ( *ang+ temp]atures are be/ se5 :]e sev]al ( !m are associat$ 7,figs4 #bi1 #cj1 & #ca74 ,! importance ( ?is me?od ( rock-break+ has r>ely be5 appreciat$ except by ^? :o h work$ 9 high & dry regions4 ,climb]s ( high m\nta9s "k t almo/ e high peak is cov]$ ) brok5 rock to su* an ext5t z to make its asc5t dang]\s to ! un9itiat$4 ,high s]rate peaks1 especially ( cry/all9e rock1 are1 z a rule1 lit]ally crumbl+ to pieces 7,fig4 #ca74 ,! piles ( talus :i* lie at ! bases ( /eep m\nta9 slopes are (t5 hundr$s ( feet 9 height1 & _! mat]ials are (t5 9 l>ge "p ! result ( ! process "h "u discussion4 ,9 m\nta9 regions :]e atmosph]ic conditions favor sudd5 *anges ( temp]ature1 ! %>p reports ( ! disruption ( rock masses are (t5 he>d4 ,masses ( rock1 scores & ev5 hundr$s ( p\nds 9 weight1 are frequ5tly ?us deta*$ & />t$ on _! d[nw>d c\rse4#bb ,small pieces ( rock are ( c\rse mu* m commonly brok5 (f ?an l>ge ones4 ,! disruption ( rock by *anges ( temp]ature is n usually ! result ( a s+le *ange ( temp]ature1 b r ( _m successive expansions & contractions4 ,! %>p ne$le-l peaks :i* m>k ! summits ( mo/ high m\nta9 ranges 7,fig4 #cb7 are l>gely develop$ by ! process "h outl9$4 ,! altitude at :i* ! s]rate topography appe>s v>ies ) ! latitude1 be+1 z a rule1 high] 9 l[ latitudes & l[] 9 high4 ,b ev5 9 ! same latitude x v>ies notably ) ! isolation ( ! m\nta9s & ) ! aridity ( ! climate4 ,?us )9 ! ,unit$ ,/ates ! %>ply s]rate summits appe> 9 "s places1 z 9 ,wa%+ton & ,oregon1 at altitudes ( #fjjj to #aj1jjj feet1 :ile 9 ! isolat$ ,wi*ita range ( ,oklahoma1 mu* f>!r s\?1 b 9 a mu* dri] climate1 ! same sort ( topography is develop$ at altitudes ( #bejj to #cjjj feet4 ,ev5 9 l[ latitudes & moi/ climates ! effects ( temp]ature *anges are (t5 se54 ,?9 b$s ( lime/one at ! bottom ( qu>ries are sometimes s exp&$ by ! heat ( ! sun z to ar* up & break4#bc ,9 des]t & arid regions1#bd :atev] ! altitude1 ! effects ( temp]ature *anges are (t5 /rik+4 ,illu/ration3 ,fig4 #cb4--,s]rate peaks ( granitic rock 9 ,black ,hills4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,! disruption ( rock by *anges ( temp]ature is "o phase ( wea!r+4 ,x t5ds to ! =mation ( a mantle ( rock wa/e1 :i*1 7 x n remov$1 w\ld soon completely cov] ! solid rock b5ea? & protect x f fur!r disruption by heat+ & cool+2 b ! loose mat]ial ?us produc$ becomes an easy prey to runn+ wat]1 s t ! "w ( ! atmosph]e prep>es ! way = t ( o!r erod+ ag5cies4 ,,ii4 ,evaporation & ,precipitation4 ,p]haps ! mo/ important "w ( ! atmosph]e z a dynamic ag5t lies 9 its function z ! m$ium = ! circulation & di/ribution ( wat]4 ,atmosph]ic temp]ature is ! prim>y factor gov]n+ evaporation1 an important factor 9 ! circulation ( ! vapor aft] x is =m$1 & controls its cond5sation & precipitation4 ,! av]age am\nt ( annual precipitation on ! l& is v>i\sly e/imat$ at f =ty to sixty in*es1 ! less] figure be+ probably m ne>ly correct4 ,s9ce mu* ( ?is wat] falls at high altitudes1 ! "w :i* x accompli%es 9 gett+ back to ! sea is great4 ,! wat] :i* falls on ! l&1 if )drawn :olly f ! ocean1 w\ld exhau/ t body ( wat] 9 #aj1jjj to #ae1jjj ye>s if none ( x return$4 ,! "w ( evaporation is ( c\rse n done by ! atmosph]e1 ?\gh ! atmosph]e det]m9es ! effect ( ! sol> en]gy :i* does ! "w4#be ,! precipitation is di/ribut$ ) great inequality1 & ?is inequality affects bo? ! ra9 & ! sn[4 ,"s regions h heavy precipitation & "s light2 "s regions h mu* ra9 & little sn[2 o!rs h mu* sn[ & little ra92 o!rs h ra9 & no sn[1 & /ill o!rs h sn[ & little or no ra94 ,! am\nt & di/ribution ( ra9 & sn[ det]m9e ! size & di/ribution ( /reams & glaci]s1 & /reams & glaci]s are ! mo/ important ag5cies modify+ ! surface ( ! l&4 ,x is impossible to sep>ate %>ply ! geologic "w ( ! wat] ( ! atmosph]e f t ( o!r wat]s2 b s long z moi/ure is 9 ! atmosph]e 7includ+ ! "t ( its precipitation7 its effects are be/ consid]$ 9 connection ) ! atmosph]e4 ,! me*anical "w ( ! ra94--,9 fall+ ! ra9 wa%es ! atmosph]e1 tak+ f x mu* ( ! du/1 spores1 etc41 :i* ! w9ds h lift$ f ! surface ( ! dry l&4 ,n only ?is1 b 9 pass+ ?r\gh ! atmosph]e ! wat] dissolves "s ( its gases1 & p]haps p>ticles ( soluble solid matt]4 ,:5 !re=e ! fall+ wat] rea*es ! surface ( ! l& x is no long] pure1 & "s ( ! gases x has tak5 up 9 its desc5t enable x to dissolve v>i\s m9]al matt]s on :i* pure wat] has little effect4 ,z x falls on ! surface ( ! l& ! ra9 produces v>i\s effects ( a me*anical nature4 ,9 ! fir/ place1 x leaves on ! surface ! solid matt] tak5 f ! air4 ,! am\nt ( mat]ial1 ?us add$ to any giv5 region 9 any p>ticul> %[] is trivial1 b 9 ! c\rse ( long p]iods ( "t ! total am\nt ( mat]ial wa%$ out ( ! air mu/ be v great4 ,e ra9-drop /rikes a bl[4 ,if ! drops fall on vegetation1 !y h little effect1 b if !y fall on s& or unprotect$ e>?y matt] !y cause movem5ts ( ! p>ticles on "o ano!r1 & ?is movem5t involves friction & we>4 ,:ile ! results ?us effect$ are inconsid]able 9 any brief p]iod ( "t1 !y are n s insignificant :5 ! long p]iods ( ! e>?'s hi/ory are consid]$4 ,clayey soils contract & (t5 crack on dry+4 ,fall+ on su* a soil :5 x is dry ! ra9 causes x to exp&1 & ! cracks are heal$ by lat]al swell+4 ,! same soils are bak$ "u ! influ5ce ( ! sun1 & :5 9 ?is condition are s(t5$ & made m mobile by ! fall+ ( ra94 ,"u ! influ5ce ( ! expansion & contraction occasion$ by wett+ & dry+1 ! soils & e>?s on slopes creep sl[ly d[nw>d4 ,:5 ra9 falls on dry s& or du/ ! cohesion is at once increas$1 & %ift+ by ! w9d is tempor>ily /opp$4 ,aft] ! wat] has fall5 on ! l& its fur!r "w _c be look$ ^u z a "p ( ! "w ( ! atmosph]e2 b any conception ( ! geological "w ( ! atmosph]e :i* did n recognize ! fact t ! wat]s ( ! l& h come ?r\gh ! atmosph]e w\ld be inadequate4 ,! "w ( ! wat] aft] x has be5 precipitat$ f ! atmosph]e mu/ be consid]$ 9 ano!r *apt]4 ,,iii4 ,effects ( ,electricity4 ,ano!r dynamic effect condition$ by ! atmosph]e is t produc$ by lightn+4 ,9 ! aggregate ?is result is inconsequ5tial2 yet in/ances are kn[n :]e l>ge bodies ( rock h be5 fractur$ by a /roke ( lightn+1 & masses _m tons 9 weight h sometimes be5 mov$ appreciable di/ances4 ,incipi5t fusion 9 v limit$ spots is also kn[n to h be5 induc$ by lightn+4 ,:]e x /rikes s& x (t5 fuses ! s& = a %ort di/ance1 &1 on cool+1 ! p>tially fus$ mat]ial is consolidat$1 =m+ a little tube or irregul> rod 7a fulgurite7 ( p>tially glassy matt]4 ,fulgurites are usually only a few in*es 9 l5g?1 & m commonly ?an o!rwise a fraction ( an in* 9 diamet]4 ,/rictly speak+ ^! results are ! effect ( ! electricity ( ! atmosph]e r ?an ( ! atmosph]e itself1 b !y are be/ m5tion$ 9 ?is connection4 ,allusion has already be5 made to ! *emical *anges 9 ! atmosph]e occasion$ by electric dis*>ges4 ,illu/ration3 ,fig4 #cc4--,/ratifi$ jo9t$ rock 9 process ( wea!r+4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cd4--,repres5ts a lat] /age ( ! processes illu/rat$ by ,fig4 #cc4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,,summ>y4 ,wea!r+4--,! result ( all atmosph]ic processes1 :e!r physical or *emical1 by :i* surface rock is disrupt$1 decompos$ or 9 any way loos5$1 is wea!r+4 ,?is conv5i5t t]m also includes simil> results effect$ by gr\nd wat]1 plants1 etc4 ,! t5d5cy ( wea!r+ is to produce a mantle ( residu>y e>? ov] solid rock4 ,wea!r+ by me*anical means t5ds to produce mat]ial :i*1 ?\gh 9 a f9] /ate ( division1 is /ill l ! orig9al rock 9 *emical composition4 ,wea!r+ by *emical means t5ds to produce a mantle made up *iefly ( ! less soluble p>ts ( ! rock f :i* x 0 d]iv$4 ,all processes ( wea!r+ prep>e mat]ial = transportation by w9d & wat]4 ,illu/ration3 ,fig #ce4--;,details ( a wea!r$ rock surface1 due p>tly to w9d "w & p>tly to solution4 ,! p>ticul> phase ( wea!r+ illu/rat$ by ?is figure is kn[n z 8honeycomb0 wea!r+4 7,gilb]t1 ,u4 ,s4 ,geol4 ,surv47 ,_m consid]ations det]m9e ! ?ickness :i* ! mantle ( wea!r$ rock 7mantle rock7 atta9s4 ,"s ( ^! consid]ations h to d ) ! atmosph]e1 & "s ) dra9age4 ,s9ce ! latt] are1 on ! :ole1 m important1 ?is matt] w be discuss$ 9 connection ) ! "w ( wat] 7,*apt]s ,,iii & ,,iv74 ,,*apt] ,,iii4 ,,! ,,"w ,,( ,,runn+ ,,wat]4 ,famili> ph5om5a1 bo? ( l& & sea1 reveal ! con/ant activity & importance ( wat] z a geologic ag5t4 ,ev5 :5 !re is no precipitation ! moi/ure 9 ! air influ5ces its activity 9 c]ta9 ways4 ,j z iron 8ru/s0 m readily 9 moi/ air ?an 9 dry1 s *anges 9 o!r m9]al sub/ances are influ5c$ by atmosph]ic humidity4 ,:]e precipitation takes place ! results are m obvi\s4 ,! pass+ %[] works *anges 9 ! surface ( ! l&1 /rik+ 9 proportion to ! rate & am\nt ( precipitation4 ,! ra9s fe$ ! /reams1 & e /ream is modify+ its b$1 & ) increas+ rapidity z its curr5t is swoll54 ,ev5 ! moi/ure :i* is precipitat$ z sn[ works its appropriate results4 ,be=e x melts x protects ! surface aga9/ o!r ag5ts ( *ange2 b if x accumulates 9 suffici5t quantity 9 appropriate situations1 x may give rise to avalan*es & glaci]s1 :i*1 l runn+ wat]1 degrade ! surface ov] :i* !y pass4 ,a "p ( ! wat] :i* falls z ra91 & a "p ( t :i* results f ! melt+ ( sn[ & ice1 s9ks into ! soil & into ! rock bel[1 becom+ gr\nd wat]4 ,x is ?is gr\nd wat] :i* especially ju/ifies ! "n hydrosph]e1 (t5 appli$ to ! wat]s ( ! e>?1 = x lit]ally =ms a sph]ical lay] 9 ! out] portion ( ! solid "p ( ! e>?4 ,dur+ ! /ay ( ! wat] b5ea? ! surface x effects *anges 9 ! rocks ?r\gh :i* x passes1 dissolv+ m9]al matt] "h & deposit+ x !re1 sub/itut+ "o sub/ance = ano!r 9 ?is place1 & effect+ new *emical comb9ations 9 t4 ,sl[ z ^! processes are1 !y h work$ wondr\s *anges 9 ! c\rse ( ! e>?'s hi/ory4 ,:5 ! wat]s are ga!r$ toge!r 9 ponds1 lakes1 & oceans1 !y are /ill active1 & ! results ( _! activity are se5 along ! %ores1 :]e w9ds & waves produce _! *iefe/ effects4 ,ev5 ! ocean curr5ts1 f> f l&1 & ! processes ( ! deep sea1 are n )\t _! effect on ! c\rse ( geological hi/ory4 ,! "w ( ! surface wat]s1 gr\nd 7und]gr\nd7 wat]s1 /&+ wat]s1 & ice w be consid]$ 9 ord]4 ,,ra9 ,,& ,,riv] ,,erosion4 ,ra9 & riv] erosion began :5 ! fir/ ra9s fell on l& surfaces4 ,nei!r ! location nor ! nature ( ! fir/ l& surface is kn[n4 ,!re is little reason to believe t ! ocean 0 ev] univ]sal1 b !re is reason to believe t mo/ l& areas h at "s "t or o!r be5 cov]$ by ! sea4 ,! preval5t conception t l& areas :i* 7 once subm]g$ came into exi/5ce by be+ elevat$ above sea-level1 %\ld be supplem5t$ by ! alt]native conception t subm]g$ areas may h become l& by ! depression ( ! ocean bas9s1 ?us draw+ (f ! wat] f ! areas :]e x 0 %all[4 ,?us 9 ,fig4 #cf ! s9k+ ( ! sea-bottom f a to b w\ld l[] ! surface ( ! wat] f cc1 to dd1 & draw (f ! wat] f ! surfaces cd & cd4 ,illu/ration3 ,fig4 #cf4--;,diagram to illu/rate ! orig9 ( l&s by ! l[]+ ( ! sea-level due to depression ( ! sea bottom4 ,if ! bottom is depress$ f a to b ! surface w be drawn d[n f cc to dd1 & ! surfaces cd & cd w become l&4 ,)\t attempt+ to picture ! "* ( ! orig9al l& our /udy ( subarial erosion may beg9 ) an area :i* has j be5 *ang$ f sea bottom to l&4 ,:at is ! nature ( su* a l& surface8 ,( :at mat]ial is x compos$1 & :at is ! "* ( its topography8 ,conc]n+ its con/itution some?+ may be inf]r$ f ! nature ( ! deposits n[ f\nd at ! bottom ( ! sea4 ,ne> ! %ore & 9 %all[ wat] !y (t5 consi/ ( gravel & s&1 ?\gh o!r mat]ials are n want+4 ,f> f %ore & 9 deep wat] !y consi/ = ! mo/ "p ( f9e s$im5ts1 "s ( :i* 7 wa%$ or bl[n f ! l&1 "s ( :i* came f ! %ells & o!r secretions ( m>9e animals1 "s f volcanoes1 & "s f v>i\s o!r s\rces4 ,! topography ( ! newly em]g$ l& may h _h "s lik5ess to ! topography ( ! sea bottom4 ,! num]\s s\nd+s :i* h be5 made ov] l>ge areas ( ! sea h %[n t its bottom is1 z a rule1 free f ! num]\s small irregul>ities :i* affect ! surface ( ! l&4 ,!y seem to %[ t a l>ge "p ( ! ocean bottom is s ne>ly flat t1 if ! wat] 7 remov$1 ! eye w\ld h>dly detect irregul>ities 9 ! surface4 ,?is /atem5t does n lose sight ( ! fact t ! ocean bottom is1 9 c]ta9 places1 m>k$ly irregul>4 ,volcanic peaks & /rik+ irregul>ities ( o!r sorts ab\nd 9 "s places4 ,nev]!less if ! bottom ( ! sea c\ld be se5 z ! l& is1 its mo/ /rik+ feature1 tak5 z a :ole1 w\ld be its app>5t flatness4 ,) ! topography ( ! sea bottom ! topography ( ! l& is1 9 its details1 9 %>p contra/4 ,9 ord] to get at ! hi/ory ( ! latt]1 we may /udy ! sequ5ce ( ev5ts :i* w\ld foll[ ! em]g5ce ( a portion ( ! =m]4 ,subarial ,erosion )\t ,valleys4 ,= ! sake ( emphasiz+ ! fundam5tal pr9ciples involv$ 9 ! "w ( runn+ wat]1 a hypo!tical case w fir/ be /udi$ 9 "s detail1 ev5 at ! risk ( elaborat+ processes already und]/ood4 ,! pr9ciples !mselves w f9d application lat] 9 relations :i* are mu* less simple4 ,let x be assum$ t ! area ( newly em]g$ l& is a circul> dome-%ap$ isl&4 ,! simple/ possible condition is repres5t$ by assum+ its slope to be ! same 9 all directions f ! c5t]1 & its mat]ials to be absolutely homog5e\s4 ,su* an isl& w\ld be subject to all ! =ces ord9>ily op]at+ on l& surfaces4 ,! *ief ag5cy t5d+ to modify l& surfaces is atmosph]ic precipitation4 ,x w be assum$ t ! ra9 falls on ! surface ( ! isl& ) absolute equality at all po9ts1 & t all o!r =ces :i* affect x op]ate equally ev]y:]e4 ,! ra9 fall+ on a l& area disappe>s 9 v>i\s ways2 "p ( x evaporates1 "p ( x s9ks1 & "p ( x runs (f ov] ! surface4 ,if ! isl& be compos$ ( f9e & unconsolidat$ mat]ials1 su* z clay1 ! wat] :i* runs (f ov] ! surface w c>ry s$im5t d[n to ! sea4 ,if ! isl& be compos$ ( solid rock in/ead1 exposure to ! air w cause x to decay1 & ! products ( decay1 su* z s& & mud1 w suff] a l fate4 ,= ! sake ( a cle> und]/&+ ( ! processes involv$1 two cases may be po/ulat$2 "o 9 :i* ! wat]s ( ! sea remove ! s$im5t wa%$ d[n f ! hypo!tical isl& z fa/ z x rea*es ! %ore1 & "o 9 :i* !y all[ x to accumulate )\t let or h9drance4 ,9 bo? cases ! we> ( ! waves w be neglect$4 #a4 ,9 ! fir/ case ! wat] fl[+ (f ov] ! surface 7! run-(f7 w desc5d equally 9 all directions4 ,x w con/itute a cont9u\s %eet ( surface-wat]1 & bo? its volume & its velocity w be ! same at all po9ts equally di/ant f ! summit4 ,erosion accompli%$ by %eets ( runn+ wat]1 z di/9ct f /reams1 is %eet 7or %eet-flood7 erosion4#bf ,s9ce ! mat]ial ( ! surface is homog5e\s1 ! we> effect$ by ! wat] w be equal at all po9ts :]e its velocity & volume are equal4 ,= obvi\s reasons ! dep? ( ! run-(f w increase f summit to base4 ,! gradi5t 7slope7 also increases 9 ! same direction1 & ! increase ( volume & ( gradi5t conspire to augm5t ! velocity ( ! wat]1 & !re=e ( ! we> effect$ by x4 ,if ! ?9 %eet ( wat] />t+ f ! top ( ! isl& ) relatively l[ velocity be able to wa% (f ev5 a little f9e mat]ial f ! surface1 ! ?ick] %eet f>!r d[n ! slope1 mov+ ) great] velocity1 w be able to c>ry away m ( ! same sort ( mat]ial1 & ! increase w be progressive f summit to base4 ,x foll[s1 !re=e1 t ! surface w be worn equally at po9ts equally di/ant f ! summit1 b unequally at po9ts unequally di/ant f x4 ,! fir/ %[] :i* falls on ! isl& may be conceiv$ to wa% (f f its surface a v ?9 %eet ( mat]ial1 b a %eet :i* increases 9 ?ickness f top to bottom4 ,! run-(f w n be /opp$ imm$iately on rea*+ ! sea1 b w displace ! sea-wat] to "s slight dep?1 & we> ! surface "s trivial di/ance bel[ ! normal level ( ! sea4 ,! result ( successive %[]s work+ 9 ! same way ?r\gh a long p]iod ( "t w be to dim9i% ! area ( ! isl& & to /eep5 its slopes4 ,! results ( a consid]able p]iod ( erosion "u ^! conditions are %[n diagrammatically 9 ,fig4 #cg1 :i* illu/rates bo? ! dim9ution 9 area :i* ! isl& has suff]$1 & ! increase 9 ! angle ( its slopes4 ,imm$iately ab\t x1 at ! /age repres5t$ by aa1 ,fig4 #cg1 !re is a n>r[ m>g9al plat=m1 or subm]g$ t]race1 9 place ( ! l& area :i* has be5 worn away at or j bel[ ! level ( ! sea4 ,long successions ( ra9s work+ 9 ! same way w give ! isl& /eep] slopes1 a small] area1 & a wid] m>g9al t]race4 ,successive /ages are %[n by ! l9es bb & cc1 ,fig4 #cg4 ,illu/ration3 ,fig4 #cg4--;,diagram to illu/rate ! effect ( ra9 erosion on an isl& :]e !re is no deposition or wave erosion ab\t its bord]s4 ,! upp]mo/ curve repres5ts ! orig9al surface1 :ile aa1 bb1 & cc repres5t successive surfaces develop$ by %eet erosion1 on ! supposition t no mat]ial is deposit$ along ! %ores4 ,if ra9 falls on su* an isl& until x completes ! "w :i* x is possible = runn+ wat] to d1 ! isl& w be r$uc$ ess5tially to ! level ( ! sea1 & 9 its place !re w be a pla91 ! area ( :i* w be equal to t ( ! orig9al isl&4 ,its c5tral po9t w be at ! level ( ! sea1 & its bord]s a trifl+ di/ance bel[ x 7,fig4 #ch74 ,! isl& is gone1 & 9 its place !re is a pla9 z l[ z runn+ wat] c we> x4 ,o!r ag5cies might come 9 to defeat ! result j outl9$1 b if ! isl& did n rise or s9k aft] its =mation1 ra9 fall+ ^u x w\ld1 "u ! conditions specifi$1 f9ally br+ ab\t ! result :i* has be5 sket*$4 ,! pla9 7,fig4 #ch7 :i* succe$s ! isl& is a base-level ( erosion1 ?\gh ?is t]m is also us$ 9 o!r ways4 ,"u ^! conditions ! slope ( ! l& w\ld rema9 convex at all /ages1 b ! convex erosion pr(ile ( ! l& w\ld meet a ne>ly /raight l9e j bel[ sea-level4 ,! relative l5g?s ( ^! two elem5ts ( ! pr(ile1 ! curve above & ! /raight l9e bel[1 v>y z erosion progresses1 ! convex portion becom+ %ort] & ! o!r long]1 ,! two p>ts ( ! pr(ile tak5 toge!r are concave upw>d at ! l[] end all ! "t1 & = a great] di/ance f its l[] end 9 all ! advanc$ /ages ( erosion 7,fig4 #cg74 ,illu/ration3 ,fig4 #ch4--;,diagram to illu/rate ! f9al effect ( ra9 erosion "u ! conditions specifi$ 9 ! text4 ,! diagram expresses ! f9al result ( ! processes sugge/$ by ,fig4 #cg4 ,9 ! de/ruction ( ! l& "u ^! conditions nei!r valleys nor hills w\ld be develop$1 nor w\ld ! topography ( ! l& be fa%ion$ to correspond ) ! surfaces ) :i* we are famili>4 ,x is to be di/9ctly borne 9 m9d t ! =ego+ is a hypo!tical case2 x is n probable t su* an isl& ev] exi/$1 or ev] w2 b t does n dim9i% ! value ( ! illu/ration1 s9ce ! pr9ciples involv$ are op]at+ on e l& mass1 ?\gh 9 less simple relations4 #b4 ,! second case diff]s f ! fir/ 9 t ! s$im5t wa%$ d[n f ! l& is deposit$ ab\t its bord]s4 ,?is results 9 ! build+ up ( a m>g9al plat=m1 z %[n 9 ,figs4 #ci-da4 ,z erosion goes on m s$im5t is wa%$ d[n & deposit$1 p>tly on ! n>r[ m>g9al %elf :i* has already be5 develop$1 & p>tly on its out] slope1 z %[n 9 ! figures4 ,! m>g9al flat is ?us ext5d$ beyond ! orig9al %ores ( ! isl& on ! "o h&1 & t[>d its c5t] on ! o!r4 ,z x develops1 its inn] portion1 & inde$ all except its out] edge 7ab1 ,figs4 #dj & #da71 w be gradually built up above ! level ( ! wat]4 ,?is m>g9al l[l& is develop$ at a level z l[ z runn+ wat]1 "u ! conditions !n & !re pres5t1 c r$uce ! l&4 ,su* a surface may be said to be at grade1 s9ce runn+ wat] nei!r we>s x d[n nor builds x up4 ,its angle ( slope is a function ( 7#a7 ! volume ( ! wat] runn+ ov] x1 & 7#b7 ( ! load :i* ! wat] c>ries4 ,illu/ration3 ,figs4 #ci-da4--;,diagrams to illu/rate ! effect ( ra9 erosion on an isl& :5 all ! erod$ mat]ial is deposit$ ab\t ! %ore4 ,! black portions repres5t deposition4 ,! dott$ l9es repres5t ! orig9al surface4 ,! sev]al diagrams repres5t successive /ages 9 ! process4 ,s9ce ! m>g9al pla9 ( ! above illu/ration ext5ds beyond ! orig9al %ore ( ! isl&1 ! area ( l& is increas$1 ?\gh bo? its av]age elevation & its mass 7above wat]7 are r$uc$4 ,9 case de/ructive processes did n op]ate on ! m>g9al grad$ pla9 ! spread+ & l[]+ sugge/$ by ,figs4 #ci & #dj w\ld g on until ! c5tral mass ( ! isl& 0 br\ght d[n to a gradi5t 9 h>mony ) t ( ! g5tly slop+ bord]1 z %[n 9 ,fig4 #da4 ,:5 ?is _h be5 accompli%$ !re w\ld be a relatively l>ge l& area ) l[ slopes 7,fig4 #da7 9 place ( ! small] area ) /eep] ones 7comp>e ,figs4 #ci & #dj74 ,! basal "p ( ! l>g] isl& f ! c5t] to ! orig9al m>g9 w\ld be made up ( ! orig9al mat]ial 9 its orig9al position 7un%ad$ "p ( ,fig4 #da74 ,its surface w\ld be cov]$1 lea/ deeply ne> its c5t] & mo/ deeply ne> ! orig9al m>g91 ) dbris gradually %ift$ f high] levels1 z %[n 9 ,fig4 #da4 ,7 su* an isl& z t %[n 9 ,fig4 #da once =m$1 ! ra9 fall+ on x1 & fl[+ (f ov] its surface1 w\ld c>ry (f its surface soil & spread x ab\t ! %ores4 ,?\gh ! surface ( ! m>g9al flat ( ,fig4 #dj 0 z l[ z runn+ wat] c\ld br+ x at ! "t x 0 develop$1 ! conditions ( erosion h *ang$ by ! "t ! l& rea*es ! conditions %[n 9 ,fig4 #da1 & ! same am\nt ( ra9fall may n[ be effective 9 erosion4 ,9 ! fir/ case 7,fig4 #dj7 ! wat] desc5d+ f ! high] "p ( ! l& br\ght d[n s$im5t & />t$ across ! flat ) a load4 ,its en]gy 0 consum$ 9 transport+ :at x _h1 n 9 gett+ new mat]ial4 ,9 ! second case 7,fig4 #da7 ! wat] fl[+ ov] ! g5tly slop+ surface has no initial load1 & its en]gy is !re=e available = erosion4 ,"u cont9u$ ra9fall1 ! area ( ! l& %[n 9 ,fig4 #da w\ld be increas$ z be=e by successive m>g9al deposits 7see ,fig4 #db71 & at ! same "t its av]age height w\ld be r$uc$4 ,! l[]+ & enl>g+ ( ! isl& w\ld cont9ue until ! :ole surface 0 br\ght s ne>ly to ! level ( ! sea t wat] w\ld cease to run ov] x ) suffici5t velocity to c>ry away ev5 ! f9e mat]ial ( its surface4 ,su* a surface1 br\ght d[n z l[ z runn+ wat] c degrade x1 is also 7see p4 #eg7 a base-level4 ,x w be se5 f ! =ego+ illu/rations t a grad$ surface may pass into a base-level1 ) no %>p] l9e ( dem>kation ?an t :i* sep>ates a mature man f an old "o4 ,9 ?is case1 z 9 ! prec$+1 ! isl& has be5 base-level$1 b /ill )\t ! =mation ( valleys or hills4 ,illu/ration3 ,fig4 #db4--;,diagram to illu/rate ! result ( ! cont9uation ( ! processes %[n 9 ,figs4 #ci-da4 ,bo? ! prec$+ hypo!tical cases make x cle> t1 f ! po9t ( view ( erosion1 e drop ( wat] :i* runs (f ov] ! surface ( ! l& has = its mission ! gett+ ( ! l& into ! sea4 ,"u ord9>y conditions surface dra9age mu/ fail to br+ a l& area altoge!r to sea-level1 ! absolute base-level ( subarial =ces2 b x is n simply ! wat] :i* runs (f ov] ! surface :i* degrades ! l&4 ,t :i* s9ks b5ea? ! surface contributes to ! same end by sl[ly dissolv+ m9]al matt] bel[ ! surface1 & f9ally c>ry+ x to ! sea4 ,9 ?is way ! r$uction ( l& areas to sea-level may be complet$4 ,! ra9-wat] :i* evaporates f ! surface )\t s9k+ b5ea? x does n effect mu* we>2 b ! wat] ?us evaporat$ is subject to reprecipitation1 s t1 9 ! long run1 x may assi/ 9 ! "w :i* has be5 sket*$4 ,?us x is n simply ! wat]s :i* run (f ov] ! surface ( ! l&1 b all :i* fall ^u x1 :i* unite to compass its de/ruction4 ,! ,developm5t ( ,valleys4 ,by ! gr[? ( gullies4--,_h ! slopes ( ! hypo!tical isl& n be5 absolutely uni=m ! processes ( erosion w\ld h be5 diff]5t4 ,let ! dep>ture f uni=mity be suppos$ to consi/ ( a s+le slight m]idional depression ne> ! base ( ! isl& 7,fig4 #dc74 ,z ! ra9 falls x w no long] run (f equally 9 all directions4 ,a great] volume w fl[ ?r\gh ! depression ?an ov] o!r p>ts ( ! surface hav+ ! same altitude1 & ! great] volume ( wat] along ?is l9e w give great] velocity1 great] velocity w occasion great] erosion1 & great] erosion w deep5 ! depression4 ,! imm$iate result is a gully or wa% 7,fig4 #dd74 ,s soon z ! gully is />t$ x t5ds /ill fur!r to conc5trate dra9age 9 itself1 & is !reby enl>g$4 ,! wat] :i* ent]s x f ! sides wid5s x2 t :i* ent]s at its head l5g!ns x by caus+ its upp] end to rec$e2 & all :i* fl[s ?r\gh x1 s long z its bottom is above base-level1 deep5s x4 ,! enl>g$ gully w ga!r m wat] to itself1 &1 z be=e1 increas$ volume means increas$ velocity1 & increas$ velocity increas$ erosion4 ,z ! gully gr[s1 !re=e1 its increas$ size becomes ! occasion ( /ill fur!r enl>gem5t4 ,illu/ration3 ,fig #dc4--;,diagram %[+ a slight m]idional depression 9 ! surface ( an o!rwise ev5-slop$ isl&4 ,cont9u$ gr[? trans=ms ! gully into a rav9e1 ?\gh betwe5 a gully & a rav9e !re is no di/9ct l9e ( dem>kation4 ,b gr[? does n /op ) rav9e-hood4 ,wat] f e %[] ga!rs 9 ! rav9e1 &1 fl[+ ?r\gh x1 increases its l5g?1 wid?1 & dep?1 until x rea*es su* proportions t ! t]m rav9e is laid aside1 z *ildhood names are1 & ! depression becomes a valley4 ,illu/ration3 ,fig4 #dd4--;,diagram illu/rat+ ! developm5t ( a gully1 />t+ f ! condition %[n 9 ,fig4 #dc4 ,x 0 assum$ 9 ! prec$+ p>agraphs t ! s+le depression 9 ! slope 0 m]idional & l[ on ! slope1 b almo/ any sort ( depression 9 almo/ any position w\ld br+ ab\t a simil> result1 s9ce x w\ld lead to conc5tration ( ! run-(f4 ,_h ! orig9al surface be5 int]rupt$ by ridges in/ead ( depressions1 ! effect on valley developm5t w\ld h be5 mu* ! same1 = a ridge1 l a depression1 w\ld1 9 almo/ any position1 occasion ! conc5tration ( ! run-(f1 & s ! developm5t ( valleys4 ,"u ! conditions repres5t$ 9 ,fig4 #dd ! l5g!n+ ( ! dra9age depression is effect$ *iefly at its upp] end1 ! head ( ! valley work+ its way f>!r & f>!r back into ! l&4 ,?is me?od ( elongation is kn[n z head erosion4 ,b ! l5g!n+ ( ! valley is n always :olly by head erosion4 ,! gully normally beg9s :]e conc5tration ( run-(f beg9s1 & if ?is 7 n at sea-level1 ! gully might be l5g!n+ at bo? ends at ! same "t4 ,?is w\ld h be5 ! case1 = example1 _h ! orig9al depression ( ,fig4 #dc be5 half-way up ! slope ( ! isl&4 ,if :ile ! slopes ( ! isl& 7 absolutely uni=m its surface mat]ial fail$ ( homog5eity1 ! result w\ld be mu* ! same z if ! slopes 7 unequal4 ,if ! mat]ial ly+ along a c]ta9 m]idian ( ! isl& be slightly s(t] ?an t ov] ! re/ ( ! surface1 ! run-(f1 :i* w\ld at ! outset be equal on all sides1 w\ld effect m erosion along ! l9e ( ! less resi/ant mat]ial ?an else:]e4 ,! result w\ld be a depression along ?is l9e1 &1 once />t$1 ! depression w\ld be a cause ( its own gr[?4 ,if ! s(t mat]ial 7 dispos$ 9 any way o!r ?an t indicat$1 ! f9al result w\ld be mu* ! same1 = x w\ld quickly give orig9 to a depression :i* w\ld lead to ! conc5tration ( ! surface-wat]s1 & ?is is ! condition = ! developm5t ( a gully1 a rav9e1 & f9ally a valley4 ,illu/ration3 ,fig4 #de4--;,diagram to illu/rate ! effect ( %eet & /ream erosion on ! outl9e ( an isl& :5 no deposition takes place ab\t its bord]s4 ,! dott$ l9e repres5ts ! orig9al outl9e ( ! isl&1 ! full l9e its bord] at a lat] "t4 ,! /ream develops a rentrant 7bay7 9 ! outl9e4 ,9 ! pres5ce ( suffici5t ra9fall1 ei!r het]og5eity ( slope or ( mat]ial w !re=e occasion ! developm5t ( valleys4 ,if ! lack ( uni=mity appe>s at b a s+le po9t !re w be b a s+le valley4 ,if x appe>s at _m po9ts ! numb] ( valleys w be l>ge4 ,s9ce x is incr$ible t a l& mass ( p]fectly homog5e\s mat]ial & ( absolutely uni=m slopes ev] exi/$1 x is believ$ t e l& mass1 affect$ = any consid]able l5g? ( "t by ra91 has _h valleys develop$ 9 x4 ,! degree ( het]og5eity ( mat]ial & slope is usually s great z to lead to ! developm5t ( _m valleys1 ev5 on areas :i* are n l>ge2 b = ! sake ( emphasiz+ ! simpl] elem5ts ( ! complex processes ( /ream "w1 ! hypo!tical case ( an isl& ) b a s+le valley1 & t )\t tribut>ies1 may fir/ be /udi$4 ,"u ^! conditions two cases may be consid]$1 ! "o :]e !re is no deposition ab\t ! isl&1 & ! o!r :]e deposition takes place4 #a4 ,if all ! mat]ial erod$ f ! surface ( su* an isl&1 bo? 9 & out ( ! valley1 7 c>ri$ well beyond ! bord]s ( ! l& be=e be+ deposit$1 ! edge ( ! isl& w\ld rec$e f its orig9al position t[>d ! c5t]1 z illu/rat$ by ,figs4 #cg & #de2 b ! recession w\ld be mo/ rapid :]e ! valley jo9s ! sea 7,fig4 #de74 ,at ?is po9t !re=e a rentrant w\ld be develop$ 7a1 ,fig4 #de71 & ! isl& w\ld lose its circul> outl9e4 ,cont9u$ erosion w\ld cause ! %ore-l9e to retreat on all sides1 b fa/e/ at ! l[] end ( ! valley1 & ! f9al result w\ld be a base-level diff]+ f t develop$ "u ! conditions specifi$ on p4 #fj1 9 t ! la/ "p to be br\ght l[ w\ld n be ! c5t] ( ! orig9al isl&4 ,"u ! =ego+ conditions ! pr(ile ( t "p ( ! valley :i* is above sea-level 7cb7 w\ld be convex1 foll[+ ! analogy ( %eet erosion on a hypo!tical isl& ( uni=m slopes & homog5e\s mat]ial ) no m>g9al deposition4 ,its side slopes1 likewise develop$ "u ! influ5ce ( runn+ wat] augm5t$ 9 volume f top to bottom1 w\ld also be convex4 ,illu/ration3 ,fig4 #df4--;,diagram %[+ ! outl9e ( an isl& z modifi$ by %eet & /ream erosion :]e erod$ mat]ial is deposit$ at ! %ore4 ,! dott$ l9e repres5ts ! orig9al outl9e2 ! full l9e1 a lat] "o4 ,! excess ( deposition at ! end ( ! valley causes a projection ( l& into ! sea4 #b4 ,if ! s$im5t wa%$ d[n f ! l& is deposit$ ab\t its bord]s1 bo? ! outl9e ( ! isl& & ! pr(ile ( ! valley w be alt]$4 ,deposition at ! deb\*ure ( ! valley foll[s ! same pr9ciples z deposition else:]e2 b if all ! s$im5t br\ght to ! sea be deposit$ at ! %ore1 ! seaw>d ext5sion ( ! l& by deposition w\ld be m rapid opposite ! valley ?an else:]e1 & ! isl& w\ld lose its circul> outl9e1 & develop "s su* =m z is %[n 9 ,fig4 #df4 ,9 ?is case ! pr(ile ( ! upp] end ( ! valley1 & ! upp] p>ts ( its side slopes1 z well z ! upp] p>ts ( ! extra-valley slopes ( ! isl&1 are convex 7comp>e ,figs4 #ci & #dj72 b ! convexity above is ex*ang$ = concavity bel[1 ! *ange beg9n+ at ! po9t :]e d[nw>d erosion ( ! desc5d+ wat]s is *eck$4 ,z a valley l5g!ns1 ! l>g] "p ( its pr(ile becomes concave 7comp>e ! pr(iles ( ,figs4 #ci to #da71 b ! extreme upp] end /ill rema9s convex4 ,s9ce ! side slopes ( a valley are mu* %ort] ?an its l5g?wise slope1 a l>g] proportion rema9s convex4 ,"u ! conditions "h discuss$ ! *ange f convexity above to concavity bel[ w\ld beg9 at ab\t ! po9t :]e deposition beg9s4#bg ,illu/ration3 ,fig4 #dg4--;,diagram repres5t+ sev]al m]idional valleys develop+ 9 a circul> isl&4 ,! valleys are all "y & n>r[4 ,all are mak+ deposits at _! deb\*ures4 ,! deposition at ! deb\*ure ( ! valley1 & lat] above ! deb\*ure1 w foll[ ! same c\rse z ab\t ! isl& "u ! conditions already discuss$ 7pp4 #fa1 #fb74 ,limits ( gr[?4--,9 all cases !re are limits 9 dep?1 l5g?1 & wid?1 beyond :i* a valley may n gr[4 ,9 dep? x may rea* base-level4 ,at ! coa/1 base-level is sea-level1#bh b inl& x rises by a g5tle gradi5t4 ,9 l5g?1 ! valley w gr[ z long z its head cont9ues to "w inl&4 ,9 ! case repres5t$ by ,figs4 #de & #df ! head ( ! valley w\ld n cease to advance :5 ! c5t] ( ! isl& 0 rea*$1 ?\gh beyond t po9t head erosion w\ld n be m rapid ?an lat]al erosion on ei!r side4 ,if b a s+le valley affect$ a l& area ! limit t[>d :i* x w\ld t5d1 & beyond :i* x c\ld nev] pass1 w\ld be ! l5g? ( ! l& area 9 ! direction ( ! valley's axis4 ,9 wid?1 a valley is increas$ by ! side cutt+ ( ! /ream1 by ! wa% ( ! ra9 :i* falls on its slopes1 & by ! action ( gravity :i* t5ds to c>ry d[n to ! bottom ( ! slope ! mat]ial :i* is loos5$ above by any process :atsoev]4 ,if !re be b "o valley 9 a l& area its limit+ wid? is sc>cely less ?an ! wid? ( ! l& itself4 ,illu/ration3 ,fig4 #dh4--,same z ,fig4 #dg1 ) ! valleys m develop$4 ,! dott$ l9e repres5ts ! orig9al outl9e ( ! isl&4 ,its area is be+ ext5d$ by deposition ev]y:]e1 b mo/ at ! deb\*ures ( ! /reams4 ,illu/ration3 ,fig4 #di4--;,a lat] /age ( ! isl& %[n 9 ,fig4 #dh4 ,illu/ration3 ,fig4 #ej4--;,diagram to illu/rate ! l[]+ ( a divide )\t %ift+ x4 ,! cre/ ( ! divide is at a1 b1 & c successively4 ,if erosion 7 unequal on ! two sides1 ! divide w\ld be %ift$4 ,_h !re be5 sev]al initial m]idional depressions in/ead ( "o 9 ! isl&1 or _h !re be5 sev]al m]idional belts :]e ! mat]ial ( ! surface 0 less resi/ant ?an else:]e1 sev]al valleys w\ld h be5 develop$1 conv]g+ t[>d ! c5t] 7,fig4 #dg74 ,if ! conditions 7 su* z to all[ ( ! equal developm5t ( valleys on all sides ( ! isl&1 ea* w\ld be l5g!n$ by head erosion until x rea*$ ! c5t] ( ! isl&1 :]e ! p]man5t divide betwe5 _! heads w\ld be e/abli%$4 ,ea* w\ld be wid5$ by all ! processes :i* wid5 valleys1 & _! wid5+ w\ld n>r[ ! int]v5+ areas 7,figs4 #dh & #di74 ,"u conditions ( equal erosion ! limits ( wid? = ea* valley w\ld be ! c5t]s ( ! ridges on ei!r side1 & "h ! divides betwe5 !m w\ld be p]man5tly e/abli%$4 ,?\gh erosion w\ld cont9ue ev5 aft] ! cre/ ( ! ridge _h be5 n>r[$ to a l9e1 ! p]man5ce ( ! divide w\ld foll[ f ! fact t erosion w\ld be equal on bo? sides ( ?is l9e1 & its effect w\ld be to l[] ! divide1 b n to %ift x horizontally 7,fig4 #ej74 ,! limits 9 l5g? & wid? are !re=e n ! same :]e !re are sev]al valleys z :]e !re is b "o4 ,! limit 9 dep?1 h[ev]1 rema9s ! same1 & ! f9al result ( erosion1 proce$+ along ^! l9es1 w\ld be ! base-level+ ( ! l&1 leav+ a pla9 b slightly above sea-level4 ,! pla9 w\ld n be absolutely flat1 ?\gh its relief w\ld be v slight1 & ! high] p>ts w\ld be along ! l9es ( ! divides betwe5 ! /reams 7,fig4 #ea4 ,comp>e also ,fig4 #db74 ,_m valleys w\ld occasion m rapid degradation ?an few1 & ! p]iod ( base-level+ w\ld be correspond+ly %ort5$4 ,_h ! initial depressions :i* gave orig9 to ! valleys _h positions o!r ?an m]idional1 ! valleys w\ld h _h o!r & less regul>ly radial c\rses1 b ! f9al result ( _! developm5t w\ld h be5 ! same4 ,x is n to be inf]r$ t ! me?od ( valley developm5t :i* has be5 sket*$ is ! only "o4 ,! processes ( valley developm5t are complex1 & ! hi/ory ( "s valleys has run a diff]5t c\rse2 yet ! processes outl9$ above are 9 op]ation 9 all cases1 & !y 7 probably ! mo/ important ones 9 ! developm5t ( ! fir/ dra9age sy/em on any l& surface4 ,z w be se5 9 ! sequel ! hi/ory ( valleys is subject to s]i\s accid5ts1 & !y are (t5 ( su* a nature z to mask ! simplicity ( ! m normal processes4 ,illu/ration3 ,fig4 #ea4--;,diagram illu/rat+ ! fur!r developm5t ( ,fig4 #di4 ,! l& "h has be5 r$uc$ greatly1 ?\gh n yet to base-level4 ,! p]man5t /ream4--,f ! =ego+ discussion1 x is se5 t a valley may be develop$ by ! run-(f ( successive %[]s4 ,if suppli$ only f ?is s\rce surface /reams w\ld cease to fl[ soon aft] ! ra9 ceas$ to fall1 & a valley might atta9 consid]able size )\t possess+ a p]man5t /ream4 ,h[ does ! valley develop$ by ! run-(f ( successive %[]s come to h a p]man5t /ream8 ,! answ] to ?is "q involves a brief consid]ation ( t "p ( ! ra9fall :i* s9ks b5ea? ! surface4 ,if wells be sunk 9 a flat region ( uni=m /ructure & composition ! wat] 9 !m is g5]ally f\nd to /& at a ne>ly common level4 ,! mean+ ( ?is fact is n f> to seek4 ,if a hole #fj feet deep fills ) wat] up to a po9t #bj feet f ! surface1 x is because ! mat]ial 9 :i* ! well is sunk is full ( wat] up to t level4 ,:5 ! well is dug ! wat] leaks into x1 fill+ ! hole up to ! level to :i* ! rock 7or subsoil7 is itself full4 ,?is level1 bel[ :i* ! rock & subsoil 7d[n to unkn[n dep?s7 are full ( wat]1 is kn[n z ! gr\nd-wat] level1 gr\nd-wat] surface1 or wat]-table4 ,! gr\nd-wat] level fluctuates4 ,9 a wet season x rises1 because m wat] has fall5 & sunk b5ea? ! soil2 b sev]al processes at once conspire to br+ x d[n aga94 ,:]e !re is gr[+ vegetation its roots draw up wat] f b5ea?1 & evaporation also goes on indep5d5tly ( vegetation4 ,! wat] is drawn out ?r\gh wells & runs out ?r\gh op5+s4 ,x may also fl[ und]gr\nd f "o region to ano!r :]e ! gr\nd-wat] surface is l[]4 ,all ^! processes depress ! gr\nd-wat] surface4 ,illu/ration3 ,fig4 #eb4--;,diagram illu/rat+ ! fluctuation ( a gr\nd-wat] surface4 a wet-wea!r gr\nd-wat] level2 b gr\nd-wat] level dur+ dr\ght4 ,well ,no4 #a w conta9 wat] dur+ ! wet season1 b w g dry 9 times ( dr\ght4 ,well ,no4 #b w be p]man5t4 ,a well sunk to su* a level z to be suppli$ ) abundant wat] 9 a wet season may g dry dur+ a p]iod ( dr\ght because ! gr\nd-wat] level is depress$ bel[ its bottom4 ,?us ei!r well %[n 9 ,fig4 #eb w h wat] dur+ a wet season :5 ! wat]-level is at a2 b well ,no4 #a w g dry :5 ! wat] surface is depress$ to b4 ,! pr9ciples applicable to wells are applicable to valleys4 ,:5 a valley has be5 deep5$ until its bottom rea*es bel[ ! gr\nd-wat] level1 wat] seeps or fl[s into x f ! sides4 ,! valley is !n no long] dep5d5t on ! run-(f ( %[]s = a /ream4 ,x w be readily se5 t at "s /age 9 its developm5t1 ! bottom ( a valley may be bel[ ! gr\nd-wat] level ( a wet season )\t be+ bel[ t ( a dry "o4 ,?us ! valley repres5t$ 9 cross-section by ! l9e #b-b1 9 ,fig4 #ec1 w h a /ream :5 ! gr\nd-wat] level is at aa1 b none :5 ?is level is depress$ to bb4 ,if ! ra9fall ( ! ye> 7 conc5trat$ 9 a s+le wet season1 ! int]mitt5t /ream w\ld fl[ n only dur+ t season1 b = s long a "t aft]w>d z ! gr\nd-wat] level rema9$ well above ! valley bottom4 ,9 regions subject to frequ5t & %ort p]iods ( heavy precipitation1 alt]nat+ ) dr\ghts1 ! p]iods ( int]mitt5t fl[ may be _m & %ort4 ,s9ce ! precipitation ( _m regions v>ies greatly f ye> to ye>1 x foll[s t a /ream may fl[ cont9u\sly "o ye> & be int]mitt5t ! next4 ,_m valleys 9 v>i\s p>ts ( ! e>? are n[ 9 ! /age ( developm5t :]e _! /reams are int]mitt5t4 ,z a valley conta9+ an int]mitt5t /ream becomes deep]1 ! p]iods :5 x is dry become %ort]1 & :5 x has be5 sunk bel[ ! l[e/ gr\nd-wat] level1 x w h a p]man5t /ream 7#c1 ,fig4 #ec74 ,s9ce a valley normally develops headw>d1 its l[] & old] portion is likely to acquire a p]man5t /ream1 :ile its upp] & y\ng] "p has only an int]mitt5t "o 7,fig4 #dg & ,fig4 #a1 ,pl4 ,,iii1 ne> ,an?ony1 ,kan4 ,! int]mitt5t "p ( ! /ream is indicat$ by ! dott$ blue l9e74 ,= ! same reason ! head ( a /ream is likely to be f>!r up ! valley 9 wet wea!r ?an 9 dry4 ,s soon z a valley gets a p]man5t /ream1 ! process ( enl>gem5t goes on )\t ! int]ruption to :i* x 0 subject :5 ! supply ( wat] 0 int]mitt5t4 ,illu/ration3 ,fig4 #ec4--;,diagram to illu/rate ! int]mitt5cy ( /reams due to fluctuations ( ! gr\nd-wat] level4 ,! wat] level aa w\ld be depress$ next ! valley #b-b by ! fl[ ( ! wat] into ! valley4 ,! pr(ile ( ! gr\nd-wat] surface w\ld !re=e be aca r ?an aa4 ,9 g5]al a p]man5t /ream at "o po9t 9 a valley means a cont9u\s /ream f t po9t to ! sea or lake :i* ! valley jo9s2 b to ?is rule !re are _m exceptions4 ,!y are likely to arise :]e a /ream heads 9 a region ( abundant precipitation1 & fl[s !nce ?r\gh an arid tract :]e ! gr\nd-wat] level is l[1 & evaporation great4 ,9 su* cases1 evaporation & absorption may dissipate ! wat] ga!r$ above1 & ! /ream disappe>s 7,fig4 #b1 ,pl4 ,,iii1 ne> ,p>adise1 ,nev474 ,illu/ration3 ,,plate ,,iii4 ,fig4 #a4 ,,kansas4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,nevada4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,iv4 ,fig4 #a4 ,,ill9ois4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,nor? ,,dakota4 ,u4 ,s4 ,geol4 ,surv4 ,o!r modes ( valley developm5t4--,if z a new area ( l& em]ges f ! sea its surface has a depression )\t an outlet1 & su* an assumption is by no means improbable1 ! depression w\ld be fill$ ) sea-wat]4 ,! infl[+ wat] f ! surr\nd+ l& might fill ! bas9 to ov]fl[+1 & ! outfl[1 f9d+ exit at ! l[e/ po9t 9 ! rim ( ! bas91 w\ld fl[ !nce t[>d ! sea4 ,su* a /ream w\ld develop a valley1 ! hi/ory ( :i* w\ld be some:at diff]5t f t :i* has be5 sket*$4 ,in/ead ( develop+ headw>d f ! sea1 ! valley w\ld be 9 process ( excavation all ! way f ! initial bas9 to ! sea at ! same "t 7,fig4 #ed74 ,! upp] end ( ! valley might ultimately be cut to ! level ( ! bottom ( ! bas91 :5 ! lake w\ld disappe>4 ,! head ( ! valley might !n "w back across ! =m] site ( ! lake into ! t]ritory beyond4 ,valleys might h develop$ above ! lake be=e x 0 dra9$1 & aft] ?is ev5t1 su* valleys w\ld make connections ) ! valley bel[ 7,fig4 #ee74 ,a valley develop$ 9 ?is mann] is n simply a gully gr[n big by head erosion1 & ! valley w\ld n prec$e ! /ream4 ,illu/ration3 ,fig4 #ed4--;,diagram to %[ h[ a valley may be develop+ all ! way f a wat]-fill$ bas9 7lake7 to ! sea at ! same "t4 ,small valleys lead+ to ! lake are also develop+4 ,! black area ! sea4 ,illu/ration3 ,fig4 #ee4--,! /ream lead+ out f ! lake 7,fig4 #ed7 has dra9$ ! lake1 & ! valleys above & bel[ ! site ( ! =m] lake h unit$4 ,if a surface ( l& 7 notably irregul> be=e valleys 7 develop$ 9 x1 !re might be _m lakes1 & ! fl[ f a high] lake might pass to a l[]4 ,if ! lakes 7 ultimately dra9$1 ! sev]al sections ( ! valley w\ld be jo9$ to "o ano!r )\t int]v5+ bas9s4 ,9 c]ta9 regions1 especially ^? :i* h be5 affect$ by cont95tal ice-%eets1 ?is has be5 a common me?od ( valley developm5t 9 po/-glacial "t4 ,9 ?is case also ! /ream prec$es its valley1 & n ! valley its /ream4 ,_m po/-glacial valleys1 on ! o!r h&1 ant$at$ _! p]man5t /reams1 z 9 ! cases fir/ describ$4 ,if ! gradi5t ( a slope on :i* valleys are to develop is notably unequal1 ?\gh )\t bas9s1 ! developm5t ( valleys may foll[ some:at diff]5t l9es4 ,if on em]g5ce ! seaw>d "p ( a new l& area assumes ! =m ( a pla91 bord]$ l&w>d by a /eep] slope 7,fig4 #ef71 ! mo/ notable e>ly gr[? ( ! valleys w\ld be on ! latt]4 ,! run-(f w\ld develop gullies on ! /eep slope1 b on rea*+ ! pla9 bel[ ! velocity ( ! wat] w\ld be *eck$1 & x w\ld drop mu* ( ! detritus wa%$ d[n f above4 ,?is deposition w\ld build up 7aggrade7 ! surface1 & mu* or ev5 all ! wat] might s9k into & seep ?r\gh ! dbris ?us deposit$1 & disappe> altoge!r f ! surface1 z at b1 ,fig4 #ef4 ,?is w\ld be mo/ likely to occur :]e ! dbris is abundant & co>se1 & ! precipitation slight4 ,if ! wat] disappe>s at ! base ( ! m\nta9 7see ,fig4 #b1 ,pl4 ,,iii71 ! e>ly gr[? ( ! valley may be conf9$ to ! /eep slope remote f ! sea 7ab1 ,fig4 #ef72 b on ! slope :]e ! valley is gr[+ !re w be headw>d l5g!n+1 z 9 ! g5]al case already consid]$4 ,if ! surface dra9age does n disappe> at ! base ( ! /eep slope1 ! run-(f w f9d its way ov] ! pla9 along ! l[e/ accessible r\te to ! sea 7de1 ,fig4 #ef74 ,9 ?is case ! valley may be gr[+ ?r\gh\t its l5g? at ! same "t4 ,illu/ration3 ,fig4 #ef4--;,diagram %[+ ! phases ( valley developm5t describ$ 9 ! text4 ,illu/ration3 ,fig4 #eg4--;,diagram repres5t+ ! fur!r developm5t ( ! valleys fg & hi 9 ,fig4 #ef4 ,! head ( ! latt] 7,fig4 #ef7 has work$ back until x has rea*$ ! l[] end ( ! =m]4 ,! conditions repres5t$ by ab1 ,fig4 #ef1 may be no m ?an tempor>y4 ,soon] or lat] a valley develop+ headw>d across ! pla9 7hi1 ,fig4 #ef7 may provide a *annel = ! wat] desc5d+ f ! high] l& beyond4 ,9 ?is case ! valley develops 9 sections1 ! "o on ! slope above1 ! o!r on ! pla9 bel[1 & _! union 7comp>e fghi1 ,fig4 #ef1 ) ,fig4 #eg7 results f _! gr[?4 ,! pr9ciples "h sket*$ h be5 9 op]ation :]ev] l& areas 7 s elevat$ z to give rise to unequal slopes1 & ?is has p]haps be5 ! rule r ?an ! exception4 ,! results effect$ by ! op]ation ( ^! pr9ciples w\ld ( c\rse be dep5d5t on ! v>ieties ( slope1 on ! abruptness ) :i* a slope ( "o gradi5t gave place to ano!r1 on ! texture ( ! rock1 ! am\nt & di/ribution ( precipitation1 etc41 etc4 ,9 ! prec$+ p>agraphs ! l5g!n+ ( a valley at its upp] end by head erosion has be5 repeat$ly ref]r$ to4 ,if all valleys began _! developm5t at ! sea & l5g!n$ headw>d1 x might seem t _! seaw>d ends %\ld be _! olde/ p>ts2 b s9ce ! developm5t ( valleys is begun some:at promptly aft] ! l& appe>s above ! sea1 & s9ce ! em]g5ce is g5]ally gradual1 t "p ( a valley :i* is at ! sea%ore at "o "t may be f> inl& a little lat]1 because ! l& has be5 ext5d$ seaw>d4 ,on an em]g+ l& area !re=e ! normal gr[? ( a valley involves its l5g!n+ at its l[] end z well z at its upp]4 ,! l5g!n+ ( a valley1 or at lea/ ! l5g!n+ ( a /ream1 also takes place at its l[] end if ! l& 9 :i* x lies is be+ ext5d$ seaw>d by deposition4 ,/ructural valleys4--,9 m\nta9 regions valleys are sometimes =m$ by ! uplift ( p>allel m\nta9 folds1 leav+ a depression betwe5 7,fig4 #eh74 ,dra9age w appropriate su* a valley s t x becomes 9 "s s5se a riv] valley4 ,b x is n a riv] valley 9 ! s5se 9 :i* ! t]m has be5 us$ 9 ! prec$+ pages4 ,x is r a /ructural valley4 ,9 its bottom a riv] valley may be develop$ 7a1 ,fig4 #eh74 ,illu/ration3 ,fig4 #eh4--,/ructural valley ) a riv] valley develop+ its bottom4 ,! =ego+ illu/rations by no means exhau/ ! li/ ( conditions "u :i* valleys develop1 b !y suffice = ! pres5t4 ,illu/ration3 ,fig4 #ei4 ,fig4 #fj4 ,figures to %[ :y ! head ( a gully 7& !re=e a valley7 dep>ts f a direct c\rse4 ,! c\rses ( valleys4--,riv] valleys are r>ely /raight4 ,to und]/& :y !y are crook$ x is only necess>y to und]/& ! me?ods by :i* !y gr[4 ,9 s f> z a riv] valley is a gully gr[n big1 t is1 9 s f> z its l5g? is ! result ( head erosion1 its c\rse 0 det]m9$ by ! c\rse ( ! antec$5t gully4 ,if 9 ! case %[n 9 ,fig4 #ei ! slope ( ! surface above ! head ( ! gully is uni=m1 its mat]ial homog5e\s1 & ! ra9fall ev]y:]e equal1 m wat] w come into ! gully f ! direction a ?an f any o!r4 ,9 ?is case !re w\ld be m we> 9 ! direct l9e ( its ext5sion ?an else:]e1 & ! head w\ld advance 9 a /raight l9e4 ,b if !re be inequalities ( slope ab\t ! head ( a gully at any /age ( its developm5t m wat] may come 9 f "s direction o!r ?an t 9 ! direct l9e ( its ext5sion4 ,9 ,fig4 #ei1 = example1 m wat] may ent] f ! direction ( b ?an f t ( a4 ,s9ce mo/ we> is likely to be affect$ along ! l9e ( greate/ infl[1 ! head ( ! gully w be turn$ 9 t direction 7,fig4 #fj74 ,/>t$ 9 ?is c\rse x w cont9ue 9 ! new direction s long z erosion 9 ?is l9e is great] ?an t else:]e2 b :5ev] ! configuration ( ! surface causes m wat] to ent] ! head ( ! gully f "s direction o!r ?an t 9 :i* x is head$1 ! l9e ( axial gr[? is aga9 *ang$1 z t[>d c1 ,fig4 #fj4 ,s9ce new l& surfaces are probably m or less undulatory1 crook$ness %\ld be ! rule among valleys develop$ f gullies by head erosion4 ,/reams & valleys ! c\rses ( :i* are det]m9$ by ! orig9al slope ( ! l& are said to be consequ5t4 ,illu/ration3 ,fig4 #fa4--;,diagram illu/rat+ ! developm5t ( two equal gullies f ! head ( "o4 ,inequalities ( mat]ial1 lead+ to unequal rates ( erosion1 effect ! same result1 9 ! abs5ce ( inequalities ( slope4 ,if at any /age ( a valley's developm5t erosion 7 equal 9 two directions at its head1 & at ! same "t great] ?an at po9ts betwe51 two gullies w\ld result 7,fig4 #fa7 div]g+ f ! po9t 9 "q4 ,9 ! case ( a valley develop$ by ov]fl[ f a lake its c\rse is det]m9$ by ! l[e/ l9e ( fl[ to :i* ! wat] has access4 ,if ?is l9e be /raight ! valley w be /raight2 if x is crook$1 z x g5]ally is1 ! valley is crook$ also4 ,! developm5t ( tribut>ies4--,?us f> valleys lead+ imm$iately to ! sea h be5 consid]$1 & no acc\nt tak5 ( tribut>ies4 ,z a matt] ( fact mo/ consid]able valleys h num]\s tribut>ies4 ,x is n[ 9 ord] to inquire into _! mode ( developm5t4 ,s soon z a gully is />t$1 ! wat] fl[+ into x f ei!r side we>s back ! slopes4 ,! lea/ inequality ( slope1 or ! lea/ v>iation 9 ! "* ( ! mat]ial1 is suffici5t to make ! lat]al erosion unequal at diff]5t po9ts1 & unequal erosion 9 ! slopes results 9 ! developm5t ( tribut>y gullies4 ,! olde/ tribut>ies may be ne>ly z old z ! ma9 :i* !y jo91 & f :i* !y develop$1 = ! possibilities ( unequal side erosion exi/ z soon z a gully is op5$4 ,:ile ! ma9 gully is develop+ into a rav9e1 & ! rav9e into a valley1 ! tribut>y gullies are likewise develop+ into matur] /ages4 ,tribut>y to a "y valley1 !re=e1 !re may be gullies ne> its head1 rav9es 9 its middle c\rse1 & small valleys along its olde/ portion4 ,x is n to be und]/ood1 h[ev]1 t ! olde/ tribut>ies are necess>ily ! l>ge/1 = because ( m favorable conditions = gr[? ! y\ng] tribut>ies (t5 out/rip ! old]4 ,illu/ration3 ,fig4 #fb4--;,diagram to illu/rate ! oblique position ( a tribut>y gully at its inception1 & its lat] normal *ange ( direction4 ,! position ( tribut>ies ) ref]5ce to _! ma9s is wor?y ( note4 ,! wat] fl[+ d[n a slope foll[s ! l9e ( /eepe/ desc5t4 ,a gully is usually wid] at its l[] end1 & n>r[] at its upp]4 ,:]ev] ?is is true ! l9e ( /eepe/ desc5t d[n its side is n a l9e p]p5dicul> to its axis1 b a l9e slightly oblique to x 7ef1 ,fig4 #fb71 & oblique 9 su* a direction t x meets ! axis ) an obtuse angle bel[ & an acute angle above4 ,x is 9 ! direction correspond+ to ?is l9e t tribut>y gullies t5d to develop4 ,?us at ! inception ( its hi/ory a tribut>y gully is likely to jo9 its ma9 ) an angle slightly acute on ! up-/ream side4 ,if ! tribut>y did n beg9 until aft] its ma9 0 f>!r advanc$ ?is t5d5cy w\ld be less & less pron\nc$4 ,inequalities ( mat]ial or slope w\ld (t5 c\nt]act ?is t5d5cy1 :i*1 at be/1 w\ld cause ! c\rses ( tribut>ies to dep>t b little f p]p5dicul>ity to _! ma9s4 ,aft] ! head ( a tribut>y has work$ back f ! imm$iate slope ( its ma9 e condition :i* det]m9es ! c\rse ( a gully is likely to affect x1 & x is by no means c]ta9 t x w cont9ue to l5g!n 9 ! direction 9 :i* x />t$4 ,s9ce ! g5]al slope ( ! surface into :i* ! tribut>y works is likely to be seaw>d1 m wat] is likely to ent] f ! l&w>d ?an f ! seaw>d side ( its head1 s t1 except :]e !re are notable irregul>ities ( slope1 its t5d5cy w be to turn m & m t[>d ! direction ( its ma9 7efg1 ,fig4 #fb74 ,9 dep? ! tribut>y is always limit$ by its ma94 ,! pr9ciples :i* det]m9e ! l5g? & wid? ( a ma9 valley det]m9e also ! l5g? & wid? ( a tribut>y 7see p4 #fg et seq474 ,a ,,cycle ,,( ,,erosion4 ,,its ,,/ages4 ,f :at has prec$$ x is cle> t ! topography ( a region und]go+ erosion w *ange greatly f "t to "t4 ,! fir/ effect ( erosion is to r\gh5 ! surface by cutt+ out valleys1 leav+ ridges & hills4 ,! f9al effect is to make x smoo? aga9 by cutt+ ! ridges & hills d[n to ! level ( ! valleys4 ,! base-level ( erosion has already be5 def9$2 b ! mode ( its developm5t may n[ be illu/rat$ 9 ! light ( ! prec$+ discussion4 ,suppose a l& surface affect$ by a s]ies ( p>allel "y valleys )\t tribut>ies 7,fig4 #fc74 ,betwe5 !m !re is a s]ies ( upl& plateaus4 ,! pr(ile ( ! surface betwe5 two adjac5t valleys is repres5t$ 9 section by ! upp]mo/ l9e 9 ,fig4 #fd4 ,z ! valleys are wid5$ f #a-a & #a1-a1 to #b-b & #b-b1 ! int]v5+ plateau is correspond+ly n>r[$4 ,:5 ! valleys h atta9$ ! =m repres5t$ by #c-c & #c-c1 ! int]v5+ upl& has be5 n>r[$ to a ridge1 a1 & ! valley flats h become wide4 ,) cont9u$ erosion ! ridge w be l[]$ 7to b & bel[71 & 9 "t ! surface w approa* a pla94 ,9 ?is condition x is kn[n z a p5epla9 7an 8almo/-pla9074 ,f9ally1 :5 runn+ wat] has done its utmo/1 ! ridges w be ess5tially oblit]at$ & a base-level$ pla9 7e1 e1 e7 results4 ,! figure expresses ! fact t ! base-level develops lat]ally f ! axis ( ! valley4 ,x also develops headw>d f ! seaw>d end ( ! valley4 ,simil>ly1 tak+ into acc\nt all ! valleys :i* affect x1 ! seaw>d m>g9 ( a base-level$ pla9 is develop$ fir/1 & !nce x ext5ds itself inl&4 ,illu/ration3 ,fig4 #fc4--;,diagram %[+ ?ree p>allel valleys 9 a l& surface4 ,illu/ration3 ,fig4 #fd4--;,diagram to illu/rate ! l[]+ ( ! surface by valley erosion4 ,! successive cross pr(iles ( ! valleys are repres5t$ by ! l9es #a-a1 #a-a1 #b-b1 #b-b1 etc4 ,tribut>ies are tol]ably sure to develop along ea* ma9 valley4 ,! heads ( ! tribut>ies "w back across ! upl&s betwe5 ! ma9 valleys1 dissect+ !m into second>y ridges 7,fig4 #fe74 ,tribut>ies w develop on ! tribut>ies1 & ^! t]ti>y valleys dissect ! second>y ridges into ^? ( a l[] ord]4 ,?is process ( tribut>y developm5t goes on until dra9age l9es ( ! f\r?1 fif?1 six?1 & high] ord]s are =m$ 7,fig4 #ff74 ,s9ce ! process ( valley developm5t "u su* circum/ances is also ! process ( ridge dissection1 a /age is pres5tly rea*$ :]e ! ridges are cut into su* %ort sections t !y cease to be ridges1 & become hills in/ead4 ,ev5 !n ! processes ( erosion d n /op1 = ! ra9-wat] fall+ on ! hills wa%es ! loose mat]ial f _! surfaces1 & />ts x on its seaw>d j\rney4 ,?us ! 8ev]la/+ hills0 !mselves are l[]$1 &1 giv5 "t en\gh1 w be c>ri$ to ! sea4 ,"u ^! conditions1 z "u ^? already discuss$1 ! f9al result ( /ream erosion is ! r$uction ( ! l& to base-level4 ,! base-level$ surface1 z be=e1 w\ld n be absolutely flat4 ,! area r$uc$ by ea* /ream w h a slight gradi5t d[n-/ream1 & f ea* lat]al divide t[>d ! axis ( ! valley4 ,! cre/s ( ! sc>cely p]ceptible elevations :i* rema9 w be 9 ! position ( ! =m] divides1 & ^! w be highe/ :]e mo/ di/ant f ! sea by ! c\rse :i* ?is "p ( ! dra9age took4 ,ev5 ! ins5sible divides betwe5 /reams fl[+ 9 a common direction may disappe>1 = :5 valleys h rea*$ _! limits 9 dep?1 _! /reams d n cease to cut lat]ally4 ,me&]+ 9 _! flat-bottom$ valleys1 !y (t5 rea* & und]cut ! divides 7,pl4 ,,vii71 :e!r !y be high or l[4 ,by lat]al planation1 !re=e1 ! divides betwe5 /reams may be entirely eat5 away4 ,illu/ration3 ,fig4 #fe4--;,diagram %[+ ! dissection ( ! upl& %[n 9 ,fig4 #fd by tribut>y valleys4 ,illu/ration3 ,fig4 #ff4--;,diagram %[+ tribut>ies ( sev]al ord]s develop$ f ! conditions sket*$ 9 ! text4 ,x has n[ be5 se5 t by :atev] me?od erosion by runn+ wat] proce$s1 :e!r !re be _m valleys1 or few or none1 ! f9al result ( subarial erosion mu/ be ! production ( a base-level4 ,x has also be5 se5 t ! base-level is fir/ develop$ at ! l[] ends ( ! ma9 /reams1 & t x ext5ds itself sy/ematically up ! ma9 valleys & up all tribut>ies4 ,! "t involv$ 9 ! r$uction ( a l& area to base-level is a cycle ( erosion4 ,x w h be5 evid5t f ! prec$+ pages t ! t]ms 8grade10 8grad$ pla910 & 8base-level0 & 8base-level$ pla910 are some:at v>i\sly1 & !re=e some:at confus+ly1 us$4 8,grade is a condition ( ess5tial balance betwe5 corrasion & deposition40#bi ,a grad$ valley is "o 9 :i* deposition & corrasion are1 9 ! v]tical s5se1 balanc$4 ,its angle ( slope is mo/ v>iable1 & is dep5d5t on ! capacity ( ! /ream = "w1 & on ! "w x has to d4 ,a weak riv] mu/ h a high] gradi5t ?an a /rong "o2 a /ream ) mu* s$im5t mu/ h a high] gradi5t ?an "o ) little1 & a /ream ) a load ( co>se mat]ial mu/ h a high] gradi5t ?an "o ) a load ( f9e4 ,?us ! grad$ valley ( ! l[] ,mississippi has an inappreciable angle ( slope1 b ! grad$ valleys ( _m ( its tribut>ies h slopes ( hundr$s ( feet p] mile4 ,s9ce bo? ! size ( ! /ream & ! am\nt & co>s5ess ( its load at a giv5 place v>y f "t to "t1 x is cle> t ! incl9ation ( a grad$ valley mu/ v>y also1 & fur!r1 t x mu/ be 9 process ( cont9ual readju/m5t4 ,) ! *ang+ conditions ( advanc+ ye>s ! slope ( a grad$ valley normally decreases4 ,! same pr9ciples apply to grad$ surfaces outside ( valleys4 ,9 ! cont9ual readju/m5t ( grades incid5t to a riv]'s normal hi/ory ! l& is br\ght ne>] & ne>] to sea-level )\t ceas+ to be at grade4 ,:5 ! incl9ation ( a grad$ surface becomes s l[ t x is s5sibly flat1 ! surface may be said to be at base-level1 al?\gh ?is does n mean t ! surface c nev] be degrad$ fur!r4 ,if ! t]m be us$ 9 ?is way1 x is cle> t !re is no %>p l9e ( di/9ction betwe5 a grad$ surface & a base-level$ surface1 & z ! t]ms are n[ commonly appli$ no su* di/9ction exi/s4 ,if ! t]m base-level 7 made synonym\s ) sea-level1 z has be5 propos$1#cj ! t]m might z well be disc>d$1 = sea-level c\ld always be us$ 9 its /ead4 ,fur!rmore1 /reams (t5 erode bel[ sea-level4 ,! bottom ( ! *annel ( ! ,mississippi is bel[ sea-level = "s #djj miles above its deb\*ure1 & locally 7,=t ,jackson7 x is ne>ly #bej feet bel[4 ,?is deep *annel is ! result ( ! erosive activity ( ! /ream1 n ( subsid5ce4 ,aga91 ! sea-level is itself incon/ant4 ,! ext5t ( its *anges _c n[ be measur$1 b !y h probably be5 m consid]able 9 ! c\rse ( geological hi/ory ?an has be5 commonly recogniz$4 ,x is true t !y take place sl[ly1 z f> z kn[n1 b x is also true t ! duration ( an erosion cycle is suffici5tly long = ev5 v sl[ *anges to rea* great magnitude4 ,! sea-level1 !re=e1 c h>dly be accept$ z ! absolute base-level1 unless 7#a7 ! absolute base-level is a v>iable1 & unless 7#b7 ! absolute base-level be a surface bel[ :i* riv]s may cut to ! ext5t ( at lea/ #bej feet4 ,! ocean may be look$ ^u z a b>ri] :i* 9 a g5]al way limits ! d[n-cutt+ ( runn+ wat]2 = only v l>ge /reams cut mu* bel[ its level4 ,o!r b>ri]s1 su* z lakes1 & ! outcrops ( h>d rock 9 a /ream's b$1 h a comp>able1 ?\gh m tempor>y1 effect on ! developm5t ( valley pla9s above4 ,pla9s ?us develop$ h be5 call$ tempor>y base-levels4 ,!y diff] f o!r grad$ pla9s 9 be+ controll$ prim>ily by a b>ri] bel[1 r ?an by conditions :i* exi/ above4 ,s9ce riv] valleys h a beg9n+ & pass ?r\gh v>i\s /ages ( developm5t be=e ! c\ntry !y dra9 is base-level$1 x is important to recognize _! v>i\s /ages ( advancem5t4 ,nor is ?is difficult4 ,an old valley & a "y "o h diff]5t *>act]i/ics1 & ! "o w\ld no m be mi/ak5 = ! o!r by ^? :o h le>n$ to int]pret !m1 ?an ! face ( an ag$ man w\ld be mi/ak5 = t ( a *ild4 ,illu/ration3 ,fig4 #fg4--;,a gully develop$ by a s+le %[]4 7,blackweld]47 ,! cycle beg9s ) ! beg9n+ ( valley developm5t1 & at t /age dra9age is 9 its infancy4 ,! type ( ! infant valley is ! gully or rav9e 7,figs4 #fg & #fh74 ,x has /eep slopes & a n>r[ bottom4 ,fig4 #a ( ,plate ,,iv repres5ts simil>1 or r old]1 rav9es 9 cont\r 7%ore ( ,lake ,mi*igan1 j nor? ( ,*icago74 ,) age1 ! valley wid5s1 l5g!ns1 & deep5s1 & passes f infancy to y\?4 ,9 ?is /age also ! valleys are relatively n>r[1 & ! divides betwe5 !m broad4 ,!y may be deep or %all[1 accord+ to ! height ( ! l& 9 :i* !y are cut1 & ! fall ( ! wat] fl[+ ?r\gh !m2 b 9 any case ! /reams fl[+ ?r\gh !m h done b a small "p ( ! "w !y are to d be=e ! c\ntry !y dra9 is base-level$4 ,figs4 #fi & #gj1 respectively1 repres5t y\?ful valleys 9 regions ( mod]ate & great relief4 ,fig4 #b1 ,plate ,,iv1 %[s a y\?ful valley 9 a region ( slight relief 7ne> ,casselton1 ,n4 ,d41 lat4 #df #dj1 long4 #ig #be74 ,! upp]mo/ l9e 9 ,fig4 #fd likewise repres5ts topographic y\?1 z %[n 9 cross-pr(ile4 ,illu/ration3 ,fig4 #fh4--;,a gully some:at old] ?an t %[n 9 ,fig4 #fg4 7,ald547 ,illu/ration3 ,fig4 #fi4--;,a "y valley 9 a region ( slight relief4 ,n only are n>r[ valleys said to be "y1 b ! t]ritory affect$ by !m is said to be 9 its topographic y\?1 s9ce b a small "p ( ! "t necess>y to r$uce x to base-level has elaps$4 ,an area is 9 its topographic y\? :5 consid]able portions ( x are /ill unaffect$ by valleys4 ,?us ! areas 7z a :ole71 z well z ! valleys1 repres5t$ on ,plate ,,iv1 are 9 _! topographic y\?4 ,x is (t5 conv5i5t to recognize v>i\s sub-/ages1 su* z e>ly1 middle1 & late1 )9 ! y\?ful /age ( valleys or topographies4 ,! diff]5t p>ts ( ! areas %[n on ,plate ,,iv1 = example1 repres5t diff]5t /ages ( y\?4 ,y\?ful /reams1 z well z y\?ful topographies1 h _! di/9ctive *>act]i/ics4 ,!y are usually swift2 _! cutt+ is ma9ly at ! bottom r ?an at ! sides1 & _! c\rses are (t5 m>k$ by rapids & falls4 ,z valleys approa* base-level !y develop flats4 ,z ! valleys & _! flats wid51 & z _! tribut>ies increase 9 numb]s & size1 a /age ( erosion is pres5tly rea*$ :]e b little ( ! orig9al upl& surface rema9s4 ,! c\ntry is l>gely r$uc$ to slopes4 ,9 ?is condition ! dra9age & ! topography :i* x has det]m9$ are said to be mature4 ,mature topography is %[n 9 cont\rs 9 ! figures ( ,plate ,v1 & 9 ! nor!rn "p ( ,plate ,,vi1 :]e slopes1 r ?an upl& or valley flats1 pr$om9ate4 ,fig4 #a ( ,plate ,v repres5ts an area 9 s\!a/]n ,k5tucky 7lat4 #cg #ab1 long4 #hc #aj72 ,fig4 #b1 an area 9 we/]n ,virg9ia4 ,plate ,,vi repres5ts an area 9 s\!rn ,cali=nia1 some:at we/ ( ,san ,b]n>d9o4 ,! ?ree areas are alike 9 repres5t+ mature dra9age1 ?\gh n ( equal /ages ( advancem5t4 ,! /rik+ diff]5ces ( topography ( ! ?ree areas are ! result ( diff]5ces 9 rock /ructure & altitude1 & w be consid]$ lat]4 ,mature topography is also %[n 9 ,fig4 #ga1 :]e ! relief is mod]ate1 & 9 ,figs4 #gb & #gc1 :]e x is great4 ,figs4 #gb & #gc illu/rate cle>ly ! univ]sal t5d5cy ( riv]s 9 regions ( notable relief to develop new flats well bel[ ! old surface ( ! region4 ,at ! same "t t ^! l[-ly+ flats are develop+1 tribut>y dra9age is dissect+ & r\gh5+ ! upp] surfaces4 ,?is process is well %[n 9 ,fig4 #gc4 ,9 bo? ,figs4 #gb & #gc ! summits ( ! m\nta9s on ei!r side ( ! valleys appe> to h _h ab\t ! same elevation4 ,! new flat is !re=e develop$ at ! exp5se ( ! old flat4 ,z w be se5 9 ! sequel1 ! fir/ flat :i* a /ream develops along its c\rse is usually some:at above base-level4 ,x is a grad$ flat4 ,illu/ration3 ,,plate ,v4 ,fig4 #a4 ,,k5tucky4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,virg9ia4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,vi4 ,,p>ts ,,( ,,los ,,angeles ,,& ,,san ,,b]n>d9o ,,c\nties1 ,,cali=nia4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #gj4--,! valley 7canyon7 ( ! ,yell[/one4 ,a "y valley 9 an elevat$ region4 ,illu/ration3 ,fig4 #ga4--,mature erosion topography 9 a region ( slight relief1 ,i[a4 7,calv947 ,illu/ration3 ,fig4 #gb4--,mature erosion 9 a m\nta9 region4 ,f m\? ( ,gray ,copp] ,gul*1 ,silv]ton1 ,colo41 quadrangle4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,! same processes :i* h made "y valleys mature w 9 "t "w fur!r *anges4 ,:5 ! gradi5ts ( ! valleys h become l[ & _! bottoms wide1 & :5 ! int]v5+ ridges & hills h become n>r[ & small1 ! dra9age & ! dra9age topography h rea*$ old age1 & ! /reams are 9 a condition ( s5ility4 ,?is is illu/rat$ by ,fig4 #a1 ,plate ,,vii 7c5tral ,kansas71 & 9 section by ! ?ird & l[] l9es 9 ,fig4 #fd4 ,topographic old age sometimes has a diff]5t expression2 ?is is %[n 9 ,fig4 #gd1 :]e mo/ ( ! surface has be5 br\ght l[4 ,! elevations :i* rise above ! g5]al pla9 are small 9 area1 b h abrupt slopes4 ,?is phase ( old-age topography is usually ! result ( ! unequal resi/ance ( ! rock degrad$4 ,! effects ( unequal rock-resi/ance w be consid]$ lat]4 ,illu/ration3 ,fig4 #gc4--,mature erosion 9 a m\nta9 region4 ,silv]ton1 ,colo4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,! m>ks ( old /reams are z *>act]i/ic z ^? ( "y ones4 ,!y h l[ gradi5ts & are sluggi%4 ,in/ead ( l[]+ _! *annels /eadily !y cut !m d[n 9 flood1 & fill !m up :5 _! curr5ts are n swoll54 ,!y me&] widely 9 _! flat-bottom$ valleys 7,fig4 #a1 ,pl4 ,,vii1 ,c5tral ,kansas7 & _! erosion1 except 9 "t ( flood1 is l>gely lat]al4 ,if ! processes ( degradation 7 to cont9ue until ! l& surface 0 br\ght to sea-level1 & ?is might be done by solution ?\gh n by me*anical erosion ( runn+ wat]1 ! riv]s w\ld no long] fl[1 & ! dra9age sy/em w\ld h rea*$ ! end ( its hi/ory--dea?4 ,n only d valleys normally pass f bir? to y\?1 f y\? to maturity1 & f maturity to old age1 b a s+le riv] sy/em may %[ ^! v>i\s /ages ( developm5t 9 its v>i\s p>ts4 ,?us 9 ! area %[n 9 ,fig4 #b1 ,plate ,,vii 7nor? c5tral ,kansas71 !re is a tract 7extreme s\?we/7 :]e ! erosion hi/ory is sc>cely begun4 ,! zone ( l& a little f>!r nor!a/1 & j rea*$ by ! heads ( ! valleys 7same figure71 is 9 its y\?4 ,! well-dra9$ & unev5 tract s\?we/ ( ! flat ( ! ,solomon ,riv] is 9 maturity1 :ile ! flat ( ! ma9 valley has ! g5]al *>act]i/ics ( old age4 ,illu/ration3 ,fig4 #gd4--;,a p5epla9$ surface :]e ! elevations are small b /eep-sid$4 ,ne> ,camp ,d\glas1 ,wis4 7,atwood47 ,! age ( valleys 9 t]ms ( erosion is also express$ m or less p]fectly by _! cross-sections4 ,! l9e #a-a 7& #a-a7 ( ,fig4 #fd repres5ts 9 cross-section a n>r[ ,v-%ap$ valley4 ,su* a section is always indicative ( y\?4 ,! /ream :i* develop$ x cut *iefly at its bottom1 n at its sides4 ,x 0 !re=e rapid1 & rapid /reams are "y4 ,! l9e #b-b1 7#b-b7 7,fig4 #fd7 %[s ! same valley at a lat] & matur] /age :5 d[nw>d cutt+ has ne>ly ceas$4 ,! wid5+ ( ! valley by slope wa% has become relatively m important ?an be=e1 & ! /ream has s f> lo/ velocity z ! result ( dim9i%$ gradi5t z to be unable to c>ry away all ! detritus wa%$ d[n f ! sides4 ,z a result ( deposition at ! bases ( ! side slopes1 a concave curve has be5 develop$4 ,up ! valley f ! po9t :]e su* a section z is repres5t$ by #b-b occurs1 ! valley may /ill h a section simil> to t repres5t$ by #a-a4 ,illu/ration3 ,,plate ,,vii4 ,fig4 #a4 ,,kansas4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,kansas4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,viii4 ,,ab\t #ae ,,miles ,,s\?we/ ,,( ,,/4 ,,l\is1 ,,miss\ri4 ,u4 ,s4 ,geol4 ,surv4 ,/ill lat] /ages ( developm5t are repres5t$ by ! cross-sections #c-c & #d-d4 ,n only has ! valley become l>g]1 b ! /ream has deposit$ detritus 7n %[n 9 ! figure7 9 ! bottom ( its valley1 develop+ an alluvial flat4 ,on ?is flat ! /ream me&]s1 & ! valley may be wid5$ by ! und]cutt+ ( ! bluffs :]ev] ! /ream 9 its w&]+s rea*es !m 7,pl4 ,,viii1 ne> ,/4 ,l\is74 ,a valley might possess ! *>act]i/ics %[n by ! cross-sections #c-c1 #b-b1 & #a-a1 ,fig4 #fd1 9 its l[]1 middle1 & upp] c\rses1 respectively4 ,! prec$+ discussion1 & ! illu/rations :i* accompany x1 give "s idea ( ! topography :i* *>act]izes an area 9 v>i\s /ages ( its erosion hi/ory4 ,:e!r ! valleys are deep or %all[1 & ! int]v5+ ridges high or l[1 dep5ds on ! orig9al height ( ! l& & its di/ance f ! sea4 ,! high] ! l&1 & ! ne>] x is to ! sea1 ! great] ! relief develop$ by erosion4 ,a plateau ne> ! sea may become m\nta9\s 9 ! mature /age ( its erosion hi/ory1 :ile a pla9 9 ! same situation w\ld only become hilly4 ,a plateau 9 ! he>t ( a cont95t w\ld h less relief 9 its maturity ?an "o ( equal elevation ne> ! sea1 s9ce ! grade-pla9 9 ! =m] position is high] ?an 9 ! latt]4 ,plates ,,iv & ,,ix %[ y\?ful topography :]e ! relief is relatively slight1 & ,plate ,x %[s y\?ful topography :]e ! relief is great4 ,simil>ly1 ,plates ,v & ,,vi %[ mature topography :]e ! relief is great1 & ,fig4 #a1 ,plate ,,iii1 %[s mature topography :]e ! relief is relatively slight4 ,topographic y\?1 topographic maturity1 & topographic old age are also indicat$ 9 o!r ways1 & especially by ! pres5ce ( features :i* riv]s t5d to de/roy4 ,if1 = example1 ! surface ( ! l&1 well above ! valley bottoms1 is m>k$ by num]\s ponds & m>%es1 x is cle> t dra9age has n yet progress$ beyond its e>ly /ages1 =1 unless ! lakes be v deep1 valleys work+ back into ! l& w f9d & dra9 !m be=e topographic maturity has be5 rea*$4 ,_! pres5ce is evid5ce t ! region :]e !y occur has n yet be5 ?or\ghly dissect$ by erosion l9es1 & !re=e has n rea*$ maturity4 ,/ill o!r m>ks ( topographic y\?1 su* z rapids1 falls1 etc41 z well z m>ks ( topographic maturity & old age1 w be m5tion$ 9 ! foll[+ pages4 ,,g5]al ,,*>act]i/ics ,,( ,,topographies ,,develop$ ,,by ,,riv] ,,erosion4 ,) ! *>act]i/ics ( riv] valleys & ! me?ods by :i* !y gr[ cle>ly 9 m9d x is easy to say :e!r riv]s h be5 ! *ief ag5ts 9 ! developm5t ( a giv5 topography4 ,riv] valleys are di/+ui%$ f o!r depressions on l& surfaces by _! l9e> =m &1 leav+ out ( consid]ation ! relatively insignificant inequalities 9 a /ream's *annel1 by ! fact t any po9t 9 ! bottom ( a riv] valley is l[] ?an any o!r po9t f>!r up ! /ream 9 ! same valley1 & high] ?an any po9t f>!r d[n ! /ream4 ,! second po9t might be o!rwise /at$ by say+ t e valley excavat$ by erosion leads to a l[] valley1 or to ! sea1 or an inl& bas94 ,/reams :i* dry up1 or o!rwise disappe> z !y fl[1 con/itute p>tial exceptions4 ,if1 !re=e1 ! depressions on a l& surface are l9e>1 lead to o!r & deep] valleys1 & f9ally to an inl& bas91 or ! sea1 & if ! elevations betwe5 ^! valleys are su* z might h be5 left by ! excavation ( ! valleys1 x is g5]ally cle> t ra9 & riv]s h be5 ! *ief factors 9 ! developm5t ( ! topography4 ,if1 on ! o!r h&1 a surface is *>act]iz$ by topographic features :i* /reams _c develop1 su* z enclos$ depressions1 or hills & ridges ^: arrangem5t is indep5d5t ( dra9age l9es1 o!r ag5ts besides ra9 & surface /reams h be5 conc]n$ 9 its developm5t4 ,,special ,,features ,,result+ ,,f ,,special ,,conditions ,,( ,,erosion4 ,_m /rik+ topographic & sc5ic features result f ra9 & riv] erosion4 ,"s ( !m dep5d prim>ily on ! conditions ( erosion1 su* z climate1 altitude1 etc41 :ile o!rs dep5d l>gely on ! /ructure & resi/ance ( ! rock4 ,betwe5 ^! two classes !re is no %>p l9e ( dem>kation4 ,illu/rations ( two types1 dep5d5t l>gely b by no means :olly on conditions indep5d5t ( ! rock1 are cit$ at ?is po9t4 ,o!rs w be m5tion$ 9 o!r connections4 ,bad-l& topography4--,to a type ( topography develop$ 9 e>ly maturity 9 c]ta9 high regions :]e ! rock is b slightly1 ?\gh unequally1 resi/ant1 a special "n is sometimes giv54 ,su* regions are t]m$ bad l&s4 ,"s idea ( bad-l& topography is ga9$ f ,figs4 #ge to #gh4 ,bad-l& topography is f\nd 9 v>i\s localities 9 ! ,we/1 b especially 9 we/]n ,nebraska & ,wyom+1 & ! we/]n p>ts ( ! ,dakotas4 ,! =mations "h are (t5 b$s ( s&/one or %ale1 alt]nat+ ) un9durat$ b$s ( clay4 ,climatic factors are also conc]n$ 9 ! developm5t ( bad-l& topography4 ,a semi-arid climate1 :]e ! precipitation is mu* conc5trat$1 seems to be mo/ favorable = its developm5t4 ,! bad-l& topography is mo/ /rik+ 9 e>ly maturity4 ,illu/ration3 ,fig4 #ge4--;,bad-l& topography4 ,nor? ( ,scott's ,bluff1 ,neb4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #gf4--,toad/ool ,p>k1 ,si\x ,co41 ,neb4 ,! peculi> topography is ! result ( erosion work+ on jo9t$ rocks ( unequal h>dness 9 an arid region ( consid]able elevation :]e ra9fall is unequally di/ribut$4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,special =ms ( valleys2 canyons4--,v>i\s conditions influ5ce ! size & %ape ( valleys1 especially 9 ! e>ly /age ( _! developm5t4 ,if ! altitude ( ! l& be great1 ! gradi5t ( ! /reams at ?is /age w be high4 ,a high gradi5t means a swift /ream1 & a swift /ream erodes *iefly at its bottom4 ,high altitudes !re=e favor ! developm5t ( deep valleys4 ,su* valleys w be n>r[ if ! conditions :i* det]m9e wid5+ are abs5t or unfavorable4 ,s9ce slope wa% is "o ( ! ma9 factors 9 ! wid5+ ( valleys1 an arid climate favors ! developm5t ( n>r[ valleys1 if !re be suffici5t wat] to ma9ta9 a vigor\s /ream4 ,n>r[ness & /eepness ( slopes w also be favor$ if ! valley is cut 9 rock :i* is capable ( /&+ ) /eep faces4 ,?us a /ream may develop a n>r[ valley 9 indurat$ rock :]e x w\ld n d s 9 loose gravel1 &1 o!r ?+s be+ equal1 x w develop a n>r[] valley 9 rock :i* is horizontally b$d$ ?an 9 rock ! b$s ( :i* are incl9$4 ,aridity1 high altitude1 & ! prop] sort ( rock /ructure !re=e favor ! developm5t ( canyons1 & _m ( ! "y valleys 9 ! we/]n "p ( ! ,unit$ ,/ates :]e ^! conditions prevail1 belong to ?is class4 ,illu/ration3 ,fig4 #gg4--;,detail ( bad-l& topography4 ,head ( ,indian ,draw1 ,wa%+ton ,co41 ,s4 ,d4 ,protoc]as s&/one on ,oreodon clay4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #gh4--;,detail ( bad-l& topography4 ,s\?we/ foot ( ,mesa ,v]de1 ,colo4 7,mat!s1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #gi4--;,gr& ,canyon ( ! ,colorado4 7,peabody47 ,illu/ration3 ,fig4 #hj4--;,gr& ,canyon ( ! ,colorado4 7,peabody47 ,illu/ration3 ,fig4 #ha4--;,diagram %[+ ! relations ( dep? & wid? ( a valley1 ! wid? ( :i* is eight times ! dep?4 ,:ile all canyons are valleys1 mo/ valleys are n canyons4 ,! di/9ction betwe5 a canyon & a valley :i* is n a canyon is n %>p4 ,! canyon dep5ds = its di/9ctive "* on ! relation ( dep?1 wid?1 & angle ( slope to "o ano!r2 b any def9ition ( ! dep?1 wid?1 & angle ( slope necess>y to con/itute a valley a canyon is arbitr>y4#ca ,9 popul> usage ! rule seems to be t if a valley is suffici5tly deep1 n>r[1 & /eep-sid$ to be di/9ctly /rik+1 x is call$ a canyon 9 regions :]e t t]m is 9 use4 ,:e!r a valley is deep1 n>r[1 & /eep-sid$ en\gh to be /rik+ cle>ly dep5ds on ! obs]v]4 ,! ,colorado ,canyon 7,figs4 #gi & #hj7 is ! greate/ canyon kn[n1 b x is r>ely m ?an a mile deep1 & :]e its dep? approa*es ?is figure x is (t5 eight1 t51 or ev5 twelve miles wide f rim to rim4 ,its wid? at bottom is little m ?an ! wid? ( ! /ream2 t is1 a few hundr$ feet4 ,its cross-pr(ile ?r\gh\t mu* ( its c\rse is !re=e n 9 keep+ ) ! conv5tional idea ( a canyon4 ,) a dep? ( "o mile & a wid? ( eight1 ! slope1 if uni=m1 w\ld h an angle ( less ?an #ae4 ,su* a valley is repres5t$ 9 ,fig4 #ha4 ,z a matt] ( fact ! slopes ( a canyon are n commonly uni=m4 ,! slopes repres5t$ 9 ,fig4 #hb correspond m ne>ly ?an ^? ( ,fig4 #ha1 to ! actual slopes ( ! ,colorado ,canyon4 ,! inequalities ( slope are occasion$ by ! inequalities ( h>dness4 ,x is p]haps ne$less to say t to an obs]v] on ! rim ( ! canyon ! slopes seem sev]al times z /eep z ^? %[n 9 ! diagrams4 ,l all valleys :i* are n>r[ relative to _! dep?1 ! ,colorado ,canyon1 great z x is1 is a "y valley2 = x repres5ts b a small "p ( ! "w :i* ! /ream mu/ d to br+ its dra9age bas9 to base-level4 ,:ile aridity & altitude are conditions :i* favor ! developm5t ( canyons1 z %[n by ! fact t mo/ canyons are high & dry regions1 !y are n indisp5sable4 ,niag>a ,riv] has a canyon bel[ its falls 7,pl4 ,,ix71 & ! surr\nd+ region is nei!r high nor arid4 ,! n>r[ "p ( ! valley has be5 develop$ by ! recession ( ! falls1 & is s "y t side erosion has n yet wid5$ ! valley or l[]$ its angle ( slope to su* an ext5t z to de/roy its canyon "*4 ,?is canyon is (t5 call$ a gorge1 a t]m frequ5tly appli$ to small valleys ( ! canyon type4 ,illu/ration3 ,fig4 #hb4--;,cross-section ( ! ,colorado ,canyon4 7,aft] ,gilb]t & ,brigham47 ,illu/ration3 ,fig4 #hc4--;,detail ( erosion 9 ! ,gr& ,canyon4 ,! inequalities ( slope are ! result ( unequal h>dness4 ,! v]tical planes :i* give ! ar*itectural effect are ! result ( jo9ts4 7,holmes47 ,plate ,x %[s portions ( ! canyons ( ! ,yell[/one & ! ,colorado riv]s respectively4 ,9 ! fir/ ! cont\r int]val is #ajj feet1 & 9 ! second1 #bej feet4 ,! horizontal scale is 7ab\t #b miles to ! in*7 9 ! fir/1 & 9 ! second4 ,^! scales %\ld be borne 9 m9d 9 int]pret+ ! map4 ,falls1 rapids1 n>r[s1 & o!r peculi> features1 due prim>ily to inequalities 9 ! h>dness ( ! rock affect$ by erosion1 w be consid]$ lat]4 ,illu/ration3 ,fig4 #hd4--;,a surface illu/rat+ ! /ruggle = exi/5ce among gullies4 ,mo/ ( ! small] gullies %[n on ! slope c h b little gr[? be=e be+ absorb$ by _! l>g] neighbors4 ,a type ( erosion surface common 9 ! ,bad ,l&s4 ,scott's ,bluff1 ,neb4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,,! ,,/ruggle ,,= ,,exi/5ce ,,among ,,valleys ,,& ,,/reams4 ,x is n to be inf]r$ t e gully becomes a valley1 nor t e small valley becomes a l>ge "o4 ,among valleys1 z among liv+ ?+s1 !re is a /ruggle = exi/5ce1 & fitness det]m9es gr[? & survival4 ,at an e>ly /age ( its erosion hi/ory ! numb] ( small valleys 9 a giv5 area is (t5 great1 :ile at a lat] /age ! numb] is less & ! size ( ! survivors great]4 ,illu/ration3 ,,plate ,,ix4 ,,niag>a ,,falls4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,x4 ,fig4 #a4 ,,yell[/one ,,p>k4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,arizona4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #he4--;,diagram illu/rat+ ! absorption ( "o gully by ano!r by lat]al erosion4 ,! successive l9es repres5t successive cross-sections4 ,"o phase ( ! /ruggle = exi/5ce is (t5 well illu/rat$ on a fre%ly expos$ slope ( clay4 ,! numb] ( m9iature gullies :i* develop on su* a slope1 ev5 9 a s+le %[]1 may be v l>ge 7,fig4 #hd72 b ! hi/ory ( _m ( !m is ephem]al4 ,if two adjac5t ones are ( unequal dep? ! wid5+ ( ! deep] n>r[s & f9ally elim9ates ! divide betwe5 !m1 & ! two become "o 7,fig4 #he74 ,ano!r phase ( ! /ruggle = exi/5ce is %[n 9 o!r situations4 ,exam9ation ( a good map ( ! nor? %ore ( ,lake ,sup]ior or ! we/ %ore ( ,lake ,mi*igan %[s a l>ge numb] ( small /reams & gullies 7,fig4 #a1 ,pl4 ,,iv74 ,! valleys are %ort & n>r[1 & betwe5 & beyond !m are consid]able areas unt\*$ by erosion4 ,! dra9age ne> ! lake is !re=e "y1 & ea* ( ! small valleys is gr[+4 ,?is condition ( ?+s is p]haps typical ( t :i* has be51 is1 or w be along ! av]age coa/ at a c]ta9 /age 9 its erosion hi/ory4 ,no equal /ret* ( coa/-l9e :]e erosion is f> advanc$ c boa/ ( a numb] ( l>ge riv]s comp>able to t ( ! _m small ones along ! coa/s m5tion$4 ,x !re=e seems evid5t t ( ^! _m small /reams a few only w atta9 consid]able size4 ,"s ( ! me?ods by :i* ! gr[? ( ! _m is arre/$ are easily und]/ood4 ,"s ( ! "y valleys on a giv5 coa/ w "w _! heads back into ! l& fa/] ?an o!rs because ( inequalities ( slope & mat]ial4 ,?is w be true ( ! tribut>ies no less ?an ( _! ma9s4 ,if valleys develop 9 ways o!r ?an by head erosion 7see p4 #gc7 ! *ances are also aga9/ _! equality ( gr[?4 ,if two /reams1 su* z a & c1 ,fig4 #hf1 develop fa/] ?an ! int]m$iate /ream b1 x is cle> t _! tribut>ies may "w back into ! t]ritory :i* at ! outset dra9$ into b1 s z to cut (f ! supply ( wat] f ! latt] /ream 7comp>e abc1 ,fig4 #hg74 ,z a result1 ! gr[? ( b w be *eck$1 & ultimately /opp$4 ,simil>ly o!r valleys1 su* z f1 w get ! bett] ( _! neighbors1 & _m ( ! competitors1 z b1 d1 e1 & g w soon drop out ( ! race4 ,betwe5 ! /rong] /reams competition /ill goes on4 ,if a & f develop fa/] ?an c its prospective dra9age t]ritory w be prempt$ by its rivals 7comp>e ,figs4 #hg & #hh74 ,?us z ! result ( ! unequal rate at :i* valleys are l5g!n$1 ! l>g] numb] ( ^? :i* come into exi/5ce are arre/$ 9 _! developm5t4 ,z a result ( gr[? 9 ! mann] indicat$1 ! bas9s ( ev5 ! l>ge /reams rema9 n>r[ at _! l[] ends :ile !y exp& above4 ,?is is ! usual =m ( a dra9age bas9 ! developm5t ( :i* has be5 normal4 ,illu/ration3 ,figs4 #hf-hh4--;,diagrams to illu/rate successive /ages 9 ! /ruggle = exi/5ce & dom9ion among /reams4 ,did valleys gr[ 9 l5g? only1 competition w\ld n de/roy ! small ones2 x w\ld simply limit !m4 ,b valleys wid5 z well z l5g!n1 & by wid5+1 adjac5t valleys may elim9ate ! divide betwe5 !m & become "o4 ,! elim9ation ( ! int]v5+ ridge may be by lat]al planation 7p4 #hb71 or1 if ! valleys be ( unequal dep?1 by slope wa% 7see ,fig4 #he74 ,by ^! & o!r processes _m "y valleys are dw>f$1 & _m o!rs are de/roy$4 ,piracy4--,/reams d n always hold ! c\rses :i* !y e/abli% = !mselves at ! outset4 ,if ! valley occupi$ by ! /ream a1 ,fig4 #hi1 is deep5$ m rapidly ?an ! valley occupi$ by b1 a tribut>y f ! =m]1 c1 may "w back across ! int]-/ream area to e & /eal ! head wat]s ( t /ream 7,fig4 #ij74 ,! tribut>y :i* does ! /eal+ is kn[n z a pirate4 ,/ream f 7,fig4 #ij7 is said to be behead$1 & its upp] portion1 de1 div]t$4 ,! behead$ /ream is dim9i%$ 9 volume2 or if its total supply ( wat] came 9 above ! po9t ( tapp+ x w\ld disappe> altoge!r4 ,illu/ration3 ,figs4 #hi & #ij4--;,diagrams to illu/rate piracy4 ,! process may n end ev5 "h4 ,if aft] ! div]sion ( de ! po9t 9 ! *annel to ! left is l[]$ fa/] ?an ! *annel ( ! behead$ /ream f1 ! divide betwe5 dg & ! head ( f 7,fig4 #ij7 w be %ift$ d[n ! valley ( ! latt]1 z %[n 9 ,fig4 #ia4 ,! %ift+ w g on until ! divide rea*es a position ( /ability1 t is1 until erosion on its opposite sides is equal4 ,! =ego+ case may be call$ =eign piracy because ! valleys ( diff]5t sy/ems are conc]n$4 ,dome/ic piracy may also take place1 z illu/rat$ 9 ! accompany+ diagrams 7,figs4 #ib & #ic74 ,"h a tribut>y to a crook$ riv] may develop1 work+ back until x taps ! ma9 at a high] po9t1 ?us /raight5+ ! c\rse ( ! /ream4 ,! *ange takes place only :5 ! highe/ po9t 9 ! tribut>y valley is br\ght bel[ ! surface ( ! wat] 9 ! ma9 /ream at ! po9t :]e ! tapp+ takes place4 ,?is w\ld be likely to occur only aft] ! ma9 /ream _h atta9$ a l[ gradi5t1 = s long z x is deep5+ its *annel notably1 ! small am\nt ( wat] fl[+ ?r\gh ! tribut>y valley w\ld n be likely to br+ x d[n to ! level ( ! ma94 ,9 any case ! fl[ ( wat] f ! ma9 /ream ?r\gh ! new valley w\ld be likely to be />t$ dur+ flood1 & at su* "t ! erosion 9 ! new *annel w\ld be great4 ,! complete & f9al div]sion ( ! /ream ?r\gh ! new *annel might be a sl[ process4 ,illu/ration3 ,fig4 #ia4--;,diagram %[+ ! %ift+ ( a divide aft] piracy4 ,illu/ration3 ,figs4 #ib & #ic4--;,dome/ic piracy4 ,! tribut>y1 a ( ,fig4 #ib1 develops headw>d until x taps ! ma9 /ream at b1 giv+ ! result %[n 9 ,fig4 #ic4 ,piracy may occur :]e ! mat]ial 9 :i* ! valleys are cut is homog5e\s2 b1 z w be se5 lat]1 het]og5eity ( mat]ial1 by det]m9+ unequal rates ( erosion1 /imulates ! piratical proclivities ( /reams4 ,an actual case ( piracy is %[n on ,plate ,,xi4 ,nor? & ,s\? ,lakes =m]ly dra9$ we/w>d to ! ,s*oh>ie ,creek1 ! pres5t head ( :i* is 9 ! extreme nor?we/ corn] ( ! map4 ,! head ( ,kaat]skill ,creek1 :i* _h a mu* high] gradi5t1 work$ back & captur$ ! head ( ! we/w>d-fl[+ /ream1 div]t+ ! dra9age f ,nor? & ,s\? ,lakes to itself4 ,s*oh>ie ,creek 0 ?us behead$4 ,plaatekill ,creek1 ne> ! s\? limit ( ! map1 appe>s to h behead$ ! creek fl[+ we/ & nor?we/1 simil>ly div]t+ its head wat]s4 ,! ,dells1 ,wis41 quadrangle 7,u4 ,s4 ,geol4 ,surv47 af=ds an illu/ration ( dome/ic piracy4 ,,rate ,,( ,,degradation4 ,! am\nt ( me*anical s$im5t :i* ! ,mississippi ,riv] c>ries to ! ,gulf ( ,mexico is e/imat$ to repres5t a rate ( degradation = ! ,mississippi bas9 ( ab\t "o foot 9 #ejjj ye>s4 ,b ! me*anical s$im5t c>ri$ to ! ,gulf does n really repres5t ! total degradation ( ! bas91 = ! wat] :i* s9ks b5ea? ! surface is dissolv+ m or less rock sub/ance1 especially lime c>bonate4 ,?is mat]ial is c>ri$ to ! sea 9 solution1 & does n appe> 9 ! s$im5t on :i* ! above e/imate is bas$4 ,tak+ into acc\nt ! matt] dissolv$ by ! wat] & c>ri$ to ! sea 9 solution1 ! av]age rate ( degradation = ! ,mississippi bas9 is e/imat$ at "o foot 9 #cjjj to #djjj ye>s4 ,x is n to be inf]r$ t ?is rate is uni=m1 or ev5 t erosion at any rate :atsoev] is tak+ place 9 all p>ts ( ! bas94 ,su* is n ! fact4 ,on ! :ole ! rate ( erosion is d\btless greate/ t[>d ! m>g9s ( ! bas9s :]e ! l& is 9 its topographic y\? or e>ly maturity4 ,x is notably less 9 ! middle c\rses ( ! valleys1 & erosion is locally exce$$ by deposition along ! l[] c\rses ( ! ,mississippi & "s ( its ma9 tribut>ies4 ,! av]age elevation ( ,nor? ,am]ica is n accurately kn[n1 b x is probably n f> f #bjjj feet4 ,if ! pres5t rate ( degradation1 say "o foot 9 #cejj ye>s1 7 to cont9ue1 x w\ld take some?+ l #g1jjj1jjj ye>s to br+ ! cont95t to sea-level4 ,b ?is rate ( degradation c\ld n cont9ue to ! end1 = z ! cont95t became l[] /reams w\ld become sluggi% & erosion less rapid4 ,long be=e ! cont95t rea*$ base-level ! rate ( degradation1 s f> z dep5d5t on me*anical erosion1 w\ld become s sl[ t ! "t necess>y to br+ ! cont95t to sea-level w\ld be almo/ inconceivably prolong$4 ,fur!rmore1 x is q possible t ! l& is suff]+1 or is liable to suff]1 uplift1 relative or absolute4 ,if ! rate ( rise 7 equal to ! rate ( degradation ! av]age height ( ! cont95t w\ld ( c\rse n be affect$4 ,! am\nt ( s$im5t c>ri$ by /reams 9 susp5sion v>ies notably accord+ to ! /age ( ! wat]4 ,dur+ a ye> :5 ! /ream 0 "u c>eful /udy ! ,mississippi at ,c>rollton 7,miss47 0 f\nd to c>ry ( its weight ( s$im5t dur+ ! high-wat] /age ( ,june1 & dur+ ! l[-wat] ( ,octob]1 ! av]age = ! ye> be+ 4 ,! av]age ( a great] numb] ( records gives ab\t z ! av]age ratio betwe5 ! weight ( ! s$im5t & ! weight ( ! wat]4 ,?is corresponds to ab\t by volume1 ! av]age specific gravity be+ ab\t #a4i4 ,! am\nt ( mat]ial c>ri$ 9 ! upp] "p ( ! wat] 0 notably less ?an t c>ri$ at great] dep?s1 b t c>ri$ midway betwe5 top & bottom 0 ab\t ! same z t c>ri$ at ! bottom4#cb ,! dis*>ge ( ! ,mississippi ,riv] is ab\t #ai1ejj1jjj1jjj1jjj cubic feet ( wat] p] ye>1 & ! s$im5t x c>ries 9 susp5sion is e/imat$ to weigh ab\t #hab1ejj1jjj1jjj p\nds4 ,?is is equival5t to ab\t #f1gad1fid1djj cubic feet4 ,x is e/imat$ t ab\t #gej1jjj1jjj cubic feet ( s$im5t is roll$ along ! bottom1 giv+ a total ( #g1dfh1fid1djj cubic feet z ! aggregate annual load c>ri$ to ! ,gulf by ! riv]4 ,?is w\ld be adequate to cov] an area "o squ>e mile 9 ext5t to ! dep? ( #bfh feet p] ye>4 ,illu/ration3 ,,plate ,,xi4 ,,"p ,,( ,,! ,,catskills1 ,,new ,,york4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xii4 ,fig4 #a4 ,,new ,,mexico4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,virg9ia1 ,,we/ ,,virg9ia ,,& ,,m>yl&4 ,u4 ,s4 ,geol4 ,surv4 ,,analyses ,,( ,,am]ican ,,riv]-,,wat]s4#cc ,r$uc$ to ,p>ts p] #ajjj by ,dr4 ,h4 ,j4 ,van ,hoes54 ---------------------------------------- ---------------------------- ,"n ( riv] ,be> ,croton ,collect$ at ,evan/on1 ,wy4 ,res]voir1 ,new ,york ,city ,date ,dec41 #ahgc #ahha ,analy/ ,f4 ,w4 ,cl>ke ,e4 ,wall] ,ref]5ce ,bullet9 ,no4 #i1 ,u4 ,wat] supply ( ,s4 ,geol4 ,surv41 ,new ,york ,city1 p4 #cj #ahha ---------------------------------------- ---------------------------- ,sodium1 ,na 4#jjhb #b4jjbih ,potassium1 ,k 444444 4#jjaed ,calcium1 ,ca 4#jdcb 4#jjije ,magnesium1 ,mg 4#jabe 4#jjccf ,*lor9e1 ,cl 4#jjdi 4#jjbac ,c>bonic acid1 ,,co1 #c4jihb #cd4jbbdh ,sulphuric acid1 ,,s 4#jaje 4#jjdda ,phosphoric acid1 ,h,,po ,nitric acid1 ,,hno 444444 444444 ,silica1 ,si,o 4#jjgj 4#jccfj ,alum9a1 ,al,o ,sesquioxide ( iron1 ,fe,o 444444 ,sesquioxides ( iron & alum9a1 ,fe,o & ,al,o 4#jjjgh iron & manganese1 ,fe,o & ,mn,o ,c>bonates ( iron & manganese1 ,fe,c,o & ,mn,c,o ,oxide ( iron1 ,fe,o manganese1 ,mn,o ,hydrog5 9 bic>bonates1 ,h ,*loride & sulphate ( sodium1 ,na,cl1 & ,na,,s ,ammonia1 ,,nh 444444 ,organic matt] 4#jjdjj ,c>bonates & sulphates ( ,na1 ,k1 & ,mg 444444 444444 ---------------------------------- 4#ahde 4#jhdcc ---------------------------------------- ---------------------------- ---------------------------------------- ---------------------------------------- ------ ,cumb]l& ,delaw>e ,hudson1 ,n4 ,y4 ,james ,los ,angeles ,maumee1 ,o4 ,res]voir at ,res]voir at ,ri*mond ,wat] ,hydrant at ,na%ville1 ,tr5ton1 ,works1 ,va4 ,los ,angeles1 ,t5n4 ,n4 ,j4 ,cal4 ---------------------------------------- ---------------------------------------- ------ ,oct4 #bd4 #ahgf1 ,sept4 #h1 #ahgh aft] light ra9 ,n4 ,t4 ,lupton ,h4 ,wurtz ,c4 ,f4 ,*&l] ,w4 ,h4 ,taylor ,w4 ,j4 ,jones ,c4 ,f4 ,*&l] ,am4 ,*emi/1 ,geol4 ( ,n4,j41 ,public ,heal? ,ann4 ,rept4 ,rept4 ,cal4 ,report ( ,july #af1 #ahgf1 #ahfh1 p4 #gjb ,pap]s1 ,vol4 ,i1,bo>d ( ,heal?1 ,/ate ,bo>d ,tol$o ,wat] p4 #af ,am4 ,pub4 ,ri*mond1 ,va41 ( ,heal?1 ,works1 #ahha ,heal? ,ass4 #ahgf #ahgh ---------------------------------------- ---------------------------------------- ------ 4#jajcb 4#jjjgb 4#jjbdd 4#jjbcd 4#jbifh 4#jjafb 4#jjjej 4#jjagh 4#jjjeh 4#jjbea 444444 4#jjcji 4#jbihg 4#jaajd 4#jbbbj 4#jabhd 4#jagej 4#jbfde 4#jjbhj 4#jjdce 4#jjdfe 4#jjcgg 4#jbjig 4#jjddc 4#jjbii 4#jjaba 4#jjeha 4#jjaje 4#jajdd 4#jjbej 4#jegbg 4#jbeeb 4#jgbgh 4#jbied 4#jefce 4#jddch 4#jjefc 4#jjage 4#jabeg 4#jjcfc 4#jegbd 4#jadja 444444 4#jjagb ,trace 4#jbfch 4#jjeaa 444444 444444 4#jjbca 444444 444444 ,trace 4#jjheb 4#jjfih 4#jajbd 4#jbjje 4#jjgbd 4#jjjda 4#jjaga 444444 4#jjjdg 444444 444444 4#jjajj 4#jjfga 4#jjabj 444444 4#jjjgb 444444 444444 4#jjddc ,trace 444444 4#jjaba 444444 444444 444444 4#jjjja 444444 4#jajhg 4#jafff 4#jaaig 4#jjbii 4#jjdii 444444 444444 444444 444444 444444 444444 ---------------------------------------- ---------------------------------------- ------ 4#acghf4 4#jfgie 4#adbch 4#jgbdf 4#bddge 4#ajiga ---------------------------------------- ---------------------------------------- ------ ---------------------------------------- ---------------------------------------- ------- ,mississippi ,ottawa ,passaic ,rio ,gr&e ,sacram5to ,/4 ,lawr5ce del ,norte ,hydrant1 ,city ,/4 ,ann's ,lock1 #d miles above ,=t ,craig1 ,hydrant1 ,s\? side ,wat] ,works1 ,montreal1 ,c4 ,new>k1 ,n4 ,j4 ,new ,mexico ,sacram5to1 ,po9t des ,new ,orleans1 ,la4 ,cal4 ,cascades ,m>4 #i1 #ahed #ahea #ahgc ,sept41 #ahgh ,m>4 #cj1 #ahfc ,w4 ,j4 ,jones ,t4 ,s4 ,hunt ,e4 ,n4 ,hors=d ,o4 ,loew ,w4 ,j4 ,jones ,t4 ,s4 ,hunt ,rept4 ,la4 ,/ate ,geol4 ( ,canada1,geol4 ( ,n4 ,j41 ,u4 ,s4 ,geog4 ,rept4 ,cal4 ,geol4 ( ,bo>d ( ,heal?1 #ahfc1 p4 #efg #ahfh1 p4 #gjh ,surv4 we/ ( ,/ate ,bo>d ,canada1 #ahhb1 p4 #cgj #ajj? ,m41 ,vol4 ( ,heal?1 #ahfc1 p4 #efg ,,iii4 p4 #egf #ahgh ---------------------------------------- ---------------------------------------- ------- 4#jcaj 4#jjbci 4#jbceg 4#jcbbj 4#jjbjj 4#jjeac 444444 4#jjaci 4#jjafc 4#jjjfc 444444 4#jjaae 4#jcgb 4#jjiib 4#jadei 4#jafcc 4#jabgi 4#jcbcc 444444 4#jjafa 4#jjdjd 4#jjabc 4#jjaba 4#jjehe 4#jdhj 4#jjjgf 4#jcaib 4#jcfjd 4#jjbdb 4#jchc 4#jbbee 4#jbfcd 4#jajbe 4#jjhhg 4#jfhcf 4#jjaid 4#jagaf 4#jdgjj 4#jjcig 4#jjhca ,trace ,fa9t trace 4#jagid ,trace 444444 ,trace 4#jbjfj ,trace 4#jcafg 4#jcgjj ,trace 4#jacdb ,trace 4#jjabj ,trace 444444 444444 444444 4#jajhh 444444 ,trace ,trace ,trace ,trace ,trace 444444 4#jbdca ,trace 444444 4#jacib 4#jaed 444444 444444 444444 444444 444444 ---------------------------------------- ---------------------------------------- ------- 4#afii 4#jfaaf 4#acbfg 4#aegfj 4#aadhd 4#afjee ---------------------------------------- ---------------------------------------- ------- ---------------------------------------- ---------------------------------------- -------------------- ,humboldt ,truckee ,walk] ,jordan ,mohawk ,g5esee ,battle ,mt41 ,nev4 ,lake ,tahoe1 ,nev4 ,mason ,valley1 ,utah ,lake ,utica1 ,n4 ,y4 ,ro*e/]1 ,n4 ,y4 ,nev4 ,dec41 #ahgb ,oct41 #ahgb ,oct41 #ahgb ,nov41 #ahgc ,t4 ,m4 ,*at>d ,f4 ,w4 ,cl>ke ,f4 ,w4 ,cl>ke ,f4 ,w4 ,cl>ke ,c4 ,f4 ,*&l] ,c4 ,f4 ,*&l] ,u4 ,s4 ,geol4 ,surv41,u4 ,s4 ,geol4 ,surv41,u4 ,s4 ,geol4 ,surv41 ,bullet9 ,no4 #i1 ,johnson's ,johnson's ,monograph ,,xi1 ,monograph ,,xi1 ,monograph ,,xi1 ,u4 ,s4 ,geol4 ,cyclop$ia1 ,cyclop$ia1 p4 #da p4 #db p4 #dj ,surv41 p4 #bi ,vol4 ,,iv ,vol4 ,,iv ---------------------------------------- ---------------------------------------- -------------------- 4#jdfg 4#jjgc 4#jcah 4#jagh 4#jjcf 4#jjdd 4#jajj 4#jjcc ,trace 444444 4#jjji 4#jjbc 4#jdhi 4#jjic 4#jbbh 4#jeeh 4#jcah 4#jdag 4#jabd 4#jjcj 4#jjch 4#jahf 4#jjfi 4#jjhif 4#jjge 4#jjbc 4#jaca 4#jabd 4#jjbc 4#jjbd #c4aedd #c4jbhg #ce4jegf 4#jfjh 4#jefi 4#jfdf 4#jdgg 4#jjed 4#jbhd 4#acjf 4#jahg 4#jdca 444444 444444 444444 444444 444444 444444 4#jcbf 4#jacg 4#jbbe 4#jajj 4#jjfg 4#jjad 4#jjac 444444 444444 4#jjac 4#jjad 444444 444444 444444 444444 444444 444444 444444 444444 444444 444444 444444 444444 4#jbcd 4#jbej 444444 444444 444444 444444 444444 444444 ---------------------------------------- ---------------------------------------- -------------------- 4#cfae 4#jgcj 4#ahjj 4#cjfj 4#aebe 4#aiebf ---------------------------------------- ---------------------------------------- -------------------- ,! foll[+ table#cf gives ! p]c5tage ( mat]ial c>ri$ 9 susp5sion by v>i\s riv]s3 ,height ,?ickness ,mean 9 ,feet ( ,s$im5t ,annual ( ,column 9 ,in*es ,dra9age ,dis*>ge ,ratio ( ( ,s$im5t if ,spread ,areas 9 79 ,cubic ,s$im5t to ) a ,base ov] ,squ>e ,feet47 p] ,total ,tons ,wat] by ( ,"o ,dra9age ,riv]4 ,miles4 ,second4 ,annually4 ,weight4 ,squ>e ,mile4 ,area4 ---------------------------------------- ------------------------------------- ,potomac #aa1jdc #bj1afj #e1eeg1bej #a 3 #c1ege #d4j 4#jjdcc ,mississippi #a1bdd1jjj #faj1jjj #djf1bej1jjj #a 3 #a1ejj #bda4d 4#jjbbc ,rio ,gr&e #cj1jjj #a1gjj #c1hcj1jjj #a 3 #bia #b4h 4#jjaaf ,uruguay #aej1jjj #aej1jjj #ad1ghb1ejj #a 3 #aj1jjj #aj4f 4#jjjhe ,rhone #cd1hjj #fe1hej #cf1jjj1jjj #a 3 #a1gge #ca4a 4#jajge ,po #bg1ajj #fb1bjj #fg1jjj1jjj #a 3 #ijj #ei4j 4#jaaci ,danube #cbj1cjj #cae1bjj #ajh1jjj1jjj #a 3 #b1hhj #ic4b 4#jjced ,nile #a1ajj1jjj #aac1jjj #ed1jjj1jjj #a 3 #b1jej #ch4h 4#jjjdb ,irrawaddy #abe1jjj #dge1jjj #bia1dcj1jjj #a 3 #a1faj #bji4j 4#jbjje ,mean #ccd1fic #bja1dfh #aji1fdi1igb #a 3 #b1gca #gf4fe 4#jjfad ---------------------------------------- ------------------------------------- ,! composition ( ra9-wat] fall+ ne> ,london1 z det]m9$ by analysis1 0 z foll[s3#cg ,organic c>bon 4#ii "p 9 #a1jjj1jjj ( wat]4 ,organic nitrog5 4#bb ,ammonia 4#ej ,nitrog5 z nitrates & nitrites 4#jg ,*lor9e #f4cj p>ts 9 ,total solids #ci4ej ,a comp>ison ( ! composition ( ra9-wat] ) t ( spr+s & riv]s gives "s idea ( ! solv5t "w ( wat]4 ,f a /udy ( ! wat] ( n9ete5 ( ! pr9cipal riv]s ( ! _w ,murray has compil$ ! foll[+ table#ch %[+ ! am\nt ( m9]al matt] 9 av]age riv] wat]3 ,,mat]ial ,,9 ,,solution ,,9 ,,"o ,,cubic ,,mile ,,( ,,av]age ,,riv] ,,wat]4#ci ,con/itu5ts4 ,tons 9 a ,cubic ,mile4 ,calcium c>bonate 7,ca,c,o7 #cbf1gaj ,magnesium c>bonate 7,mg,c,o7 #aab1hgj ,calcium phosphate 7,ca,p,o7 #b1iac ,calcium sulphate 7,ca,s,o7 #cd1cfa ,sodium sulphate 7,na,,s7 #ca1hje ,potassium sulphate 7,k,,s7 #bj1ceh ,sodium nitrate 7,na,n,o7 #bf1hjj ,sodium *loride 7,na,cl7 #af1feg ,li?ium *loride 7,li,cl7 #b1dfb ,ammonium *loride 7,,nh,cl7 #a1jcj ,silica 7,si,o7 #gd1egg ,f]ric oxide 7,fe,o7 #ac1jjf ,alum9a 7,al,o7 #ad1cae ,manganese oxide 7,mn,o7 #e1gjc ,organic matt] #gi1jbj ------- ,total dissolv$ matt] #gfb1ehg ,murray also e/imates t ! aggregate am\nt ( wat] fl[+ into ! sea annually is ab\t #febh cubic miles1 :i*1 on ! above basis1 w\ld c>ry ab\t #d1ige1jjj1jjj tons ( m9]al matt] 9 solution4 ,a l>ge numb] ( analyses ( wat]s ( riv]s f ! ,unit$ ,/ates & ,canada give an av]age ( ab\t 4#ae1jdd "p 9 a ?\s& ( m9]al matt] 9 solution1 m ?an "o-?ird be+ ,ca,c,o4 ,! av]age am\nt ( m9]al matt] 9 solution 9 #dh ,european /reams cit$ by ,bis*(f#dj is 4#babg "p 9 a ?\s&1 ( :i* ,ca,c,o is r m ?an half4 ,! av]age m9]al matt] 9 solution 9 #cf riv]s cit$ by ,ro?#da 7includ+ "s ( ^? tabulat$ by ,bis*(f7 is 4#bjcc "p 9 a ?\s&1 ( :i* ,ca,c,o is slightly less ?an "o-half4 ,an av]age = ,am]ican & ,european riv]s1 s f> z det]m9able f data at h&1 is ab\t 4#ahhh "p 9 a ?\s& 9 solution1 ( :i* ,ca,c,o is slightly less ?an "o-half4 ,^! la/ figures are probably n v f> f an av]age = riv] wat] 9 g5]al4 ,! foll[+ table %[s ! total am\nt ( solids c>ri$ 9 solution by ! riv]s indicat$3#db ,rh9e #e1haf1hje tons p] ye>4 ,rhone #h1bij1dfd ,danube #bb1eba1dcd ,?ames #fac1icj ,nile #af1iej1jjj ,croton #ff1gie ,hudson #dch1jjj ,mississippi #aab1hcb1aga ,,economic ,,consid]ations4 ,c]ta9 consid]ations ( human int]e/ 9 connection ) riv] erosion are wor?y ( note4 ,:5 a dra9age sy/em has rea*$ its mature /age its bas9 has ! r\ghe/ topography :i* x w h at any "t dur+ t cycle ( erosion4 ,at t /age1 !re=e1 road con/ruction is relatively difficult4 ,if ! relief be great1 roads mu/ foll[ ! valleys1 or ! cre/s ( ! ridges betwe5 !m1 if !y w\ld avoid heavy grades4 ,9 su* regions roads are usually few & crook$4 ,! /age ( developm5t ( valleys has an influ5ce on ! navigability ( _! /reams4 ,/reams well advanc$ 9 life are mu* m readily navigable ?an "y ones1 because _! grades are l[] & _! volumes ( wat] great]4 ,old /reams1 on ! o!r h&1 are sometimes deposit+ s& or silt along _! l[] c\rses to su* an ext5t z to int]f]e ) navigation4 ,at c]ta9 /ages ( _! developm5t ! p[] ( /reams is m easily utiliz$ ?an at o!rs4 ,"y /reams1 dep5d+ z !y d = _! supply on ! ra9fall ( a limit$ area1 are likely to be fitful 9 _! fl[1 & !re=e unreliable z a s\rce ( p[]4 ,?is is especially true :]e ! precipitation is unequally di/ribut$1 & :]e ! slopes are /eep & free f =e/s4 ,because ( _! great volume1 old & l>ge /reams1 ?\gh sluggi%1 h great p[]1 b x is less easily controll$4 ,:]e /reams are l>ge en\gh to be navigable indu/rial consid]ations (t5 prev5t ! utilization ( _! p[]1 ! /reams be+ m s]viceable z highways ?an z s\rces ( p[]4 ,o!r ?+s be+ equal1 x foll[s t /reams are mo/ available = wat]-p[] :5 !y are l>ge en\gh to h a mod]ately /eady fl[1 & n s l>ge z to be beyond ready control1 or to be valuable = purposes ( navigation4 ,/reams are subject to m disa/r\s floods 9 "s /ages ( _! developm5t ?an 9 o!rs4 ,floods result+ f heavy ra9s are likely to be greate/ :]e ! slopes above ! dra9age l9es are on ! :ole greate/1 = ?is is ! condition "u :i* ! wat] is mo/ quickly ga!r$ into ! dra9age *annels4 ,! mo/ disa/r\s floods1 humanly speak+1 are ^? :i* affect wide-bottom$ valleys1 :]e ! flats are settl$4 ,9 su* cases a relatively slight rise may flood v ext5sive areas4 ,9 su* valleys ! mo/ disa/r\s floods are g5]ally 9 ! spr+1 :5 ! wat]s f ! melt+ sn[s ( ! prec$+ w9t] are be+ dis*>g$4#dc ,_m o!r consid]ations ent] into ! problem ( floods4 ,! pres5ce ( =e/s & o!r =ms ( vegetation on ! slopes ret>ds ! fl[ ( wat] into ! valleys1 & s t5ds to prev5t floods1 or at any rate to make !m less sev]e4 ,por\s soil & subsoil1 or 9 _! abs5ce por\s rock1 absorb ! ra9fall1 & prev5t its prompt desc5t into ! valleys & s t5ds to prev5t or dim9i% floods4 ,! acreage ( arable l& )9 a giv5 area /&s 9 "s relation to its dra9age developm5t4 ,at an e>ly /age 9 its erosion hi/ory1 be=e an upl& has be5 dissect$ by valleys1 ne>ly all ( x may be arable4 ,lat]1 :5 dra9age is at its maturity1 & :5 hillsides & ridge slopes con/itute a l>ge "p ( ! area1 !re is probably ! lea/ acreage ( arable l&4 ,?is is especially true if ! slopes are s /eep z to all[ ! soil to be readily wa%$ away4 ,at a /ill lat] /age1 :5 ! valley bottoms h become wide & ! slopes ( ! ridges & hills s r$uc$ z to be available1 ! area ( cultivable l& is aga9 increas$4 ,m>%es1 ponds1 & lakes h "s be>+ on ! res\rces & indu/ries ( a region1 & !y /& 9 a m or less def9ite relation to ! /age ( erosion 9 :i* a region f9ds itself4 ,9 its y\? ponds & lakes may occupy mu* ( ! surface2 9 its maturity !y w h be5 l>gely dra9$4 ,^! sugge/ions are suffici5t to %[ t ! topography ( a region1 ev5 9 s f> z %ap$ by erosion1 t\*es human int]e/s at _m po9ts4 ,,analysis ,,( ,,erosion4#dd ,erosion is ! t]m appli$ to all ! processes by :i* e>?y matt] or rock is loos5$ & remov$ f "o place to ano!r4 ,x consi/s ( ?ree sub-processes1 namely1 wea!r+1 transportation1 & corrasion4 ,wea!r+4 ,! t]m wea!r+ is appli$ to ne>ly all ^? natural processes :i* t5d to loos5 or *ange ! expos$ surfaces ( rock4 ,! lett]+ ( inscriptions on expos$ m>ble becomes fa9t] & fa9t] z "t goes by1 & f9ally disappe>s1 because ! rock 9 :i* ! lett]s 7 cut has wea!r$ away4 ,"s ( x has crumbl$ (f z ! result ( ! expansion & contraction induc$ by *anges ( temp]ature1 & "s ( x has be5 dissolv$ by ! ra9 :i* has fall5 ^u x4 ,9 ?is case ! wea!r+ is effect$ p>tly by ! atmosph]e & p>tly by wat]4 ,^! are ! *ief1 b n ! only ag5ts conc]n$ 9 ! g5]al processes ( wea!r+4 ,^? phases ( wea!r+ :i* are ! result ( ! activities ( ! atmosph]e1 :e!r physical or *emical1 h be5 discuss$ 9 connection ) ! atmosph]e 7pp4 #db & #ed74 ,! ra9 :i* falls ^u ! surface ( expos$ rock1 & t :i* s9ks ?r\gh ! soil to ! solid rock bel[1 dissolves1 ev5 if sl[ly1 "s ( ! rock con/itu5ts4 ,ea* con/itu5t ( a rock compos$ ( sev]al m9]als may be look$ ^u z a b9d+ mat]ial = ! o!rs4 ,:5 "o is dissolv$ ! rock crumbles1 mu* z mort> does :5 ! lime :i* cem5ts ! s& is dissolv$4 ,! solution ( m9]al matt] by gr\nd wat]1 z well z ! o!r *emical *anges x effects1 is greatly augm5t$ by ! impurities1 especially c>bonic & o!r organic gases1 dissolv$ by ! wat] f ! atmosph]e & ! soil4 ,! commone/ *emical *anges effect$ by ! jo9t action ( wat] & air1 oxidation & c>bonation1 h be5 ref]r$ to 9 ,*apt] ,,ii4 ,hydration is m exclusively ! "w ( wat]1 & is "o ( ! commone/ processes ( rock *ange1 & (t5 ( rock dis9tegration4 ,num]\s o!r less simple *emical *anges result+ f ! activities ( gr\nd wat] are con/antly 9 progress1 & 9 s f> z !y lead to ! dis9tegration ( rock are processes ( wea!r+4 ,_m *emical *anges involve notable *anges 9 volume ( ! m9]al matt] conc]n$4 ,m]rill has calculat$ t 9 ! conv]sion ( ! granitic rock ( ! vic9ity ( ,wa%+ton1 ,d4 ,c41 into soil1 its volume has be5 increas$ #hh p]c5t41 l>gely z ! result ( hydration4#de ,ev5 :5 ! *emical *anges d n !mselves directly involve ! dis9tegration ( ! rock1 ! accompany+ increase ( volume is sometimes suffici5t to cause its physical disruption4 ,?is also may be reg>d$ z a phase ( wea!r+4 ,! wea!r+ accompli%$ by wat]1 or "u its influ5ce1 proce$s at rates :i* v>y ) ! composition ( ! rock1 ! am\nt & composition ( ! wat]1 ! temp]ature1 & c]ta9 o!r factors less susceptible ( brief /atem5t4 ,! wea!r+ effect$ by gr\nd wat] has a wid] range bo? 9 area & dep? ?an t due to *anges ( temp]ature1 = :ile ! latt] is effective only :]e temp]ature *anges are consid]able1 & :]e coh]5t mat]ial lies at ! surface 7p4 #de71 ! =m] is op]ative to all dep?s to :i* wat] s9ks4 ,illu/ration3 ,fig4 #id4--,talus accumulation at ! base ( a /eep bluff4 ,web] ,canyon1 ,u9ta ,m\nta9s1 ,utah4 ,! talus has accumulat$ s9ce ! la/ glaciation ( ! valley & is !re=e ( v rec5t orig94 7,*ur*47 ,!re are o!r processes ( wea!r+ n due directly ei!r to ! atmosph]e or to wat]4 ,! roots ( trees & small] plants frequ5tly gr[ into cracks ( rocks1 &1 increas+ 9 size1 act mu* l freez+ wat] 7p4 #de7 9 simil> situations4 ,?is w$ge-"w ( roots is a phase ( wea!r+4 ,f ! faces ( /eep cliffs masses ( rock frequ5tly fall4 ,h[ev] dislodg$1 _! desc5t is effect$ by gravity4 ,! quantities ( dbris at ! bases ( _m cliffs1 =m+ slopes ( talus 7,fig4 #id71 te/ify to ! importance ( ! action ( gravity 9 gett+ mat]ial f high] to l[] levels4 ,ano!r phase ( gravity-"w is %[n 9 ,fig4 #ie4 ,"h1 "u ! influ5ce ( gravity & expansion & contraction1 due to freez+ & ?aw+ & wett+ & dry+1 ! surface mat]ial is creep+ d[n slope4 ,9 ! process ! rock is be+ brok54 ,! process illu/rat$ by ! figure involves wea!r+ z well z o!r factors4 ,! =ego+ are among ! common] processes ( wea!r+1 al?\gh !y d n exhau/ ! li/4 ,! m active & tangible processes by :i* surface rocks are brok5 up1 su* z wave we>1 riv] we> & glaci] we>1 are processes ( corrasion4 ,! me*anical we> effect$ by w9d-driv5 s& might be consid]$ ei!r z corrasion or z wea!r+4 ,x is m likely to be reg>d$ z corrasion if ! am\nt ( we> is consid]able en\gh to be obvi\s4 ,rock is sometimes decompos$ by ! *emical action ( hot vapors1 gases1 & wat]s ris+ to ! surface f consid]able dep?s4 ,?is is (t5 se5 9 volcanic regions4 ,a conspicu\s illu/ration is se5 9 ! canyon ( ! ,yell[/one 9 ! ,national ,p>k4 ,decay ( ?is sort is p]haps n prop]ly wea!r+1 b is n always readily di/+ui%$ f x4 ,illu/ration3 ,fig4 #ie4--,%[s ! d[nw>d creep ( soil & slaty rock "u ! influ5ce ( gravity4 ,! importance ( wea!r+ 9 ! g5]al processes ( erosion is %[n 9 _m ways4 ,9 regions :]e ! mantle rock is ! product ( ! decay ( ! solid rock b5ea?1 & su* regions con/itute a l>ge portion ( ! e>?'s surface1 ! soil & subsoil repres5t ! excess ( wea!r+ ov] transportation4 ,s9ce mo/ ( ! e>?'s surface is cov]$ ) soil to a great] or less dep?1 x is cle> t1 on ! :ole1 wea!r+ keeps ahead ( transportation4 ,aga91 x is cle> t ! loos5+ ( rock by wea!r+ greatly increases ! erosion :i* a giv5 am\nt ( mov+ wat] c accompli%4 ,n only ?is1 b wea!r+ plays a mu* m important rle 9 ! developm5t ( valleys ?an is commonly realiz$4 ,?is is be/ illu/rat$ by ! valleys ( "y swift /reams4 ,! valley :i* is n at its top t5 times z wide z its /ream is r>e4 ,! /ream :i* has su* a canyon has be5 cutt+ *iefly at its bottom4 ,ignor+ its lat]al corrasion1 :i* is slight1 ! valley :i* x w\ld cut w\ld h a wid? equal to its own4 ,?is is illu/rat$ by ,fig4 #if4 ,wea!r+ 9 its broade/ s5se is l>gely responsible = ! wid? ( su* a valley1 9 s f> z x exce$s ! wid? ( ! /ream4 ,! "w ( wea!r+1 slope wa%1 etc41 has be5 to get ! mat]ial :i* orig9ally lay betwe5 a1 b1 & c d[n to ! /ream4 ,! /ream has !n c>ri$ x away4 ,! above illu/ration w\ld n apply to old & sluggi% /reams1 = !y1 by _! me&]+1 wid5 _! valleys indep5d5tly ( wea!r+4 ,illu/ration3 ,fig4 #if4--;,diagram ( a valley ! top ( :i* is t5 times ! wid? ( ! /ream4 ,wea!r+ is a "p ( erosion1 b only a "p4 ,9 s f> z x is effect$ by solution ! process involves ! transportation ( t :i* is dissolv$ to "s o!r po9t4 ,transportation is also involv$ to "s ext5t 9 ! o!r processes ( wea!r+1 b ! c5tral idea ( ! processes embrac$ "u ?is t]m is ! loos5+ & disrupt+ ( rock by :i* x is prep>$ = transportation4 ,transportation4 ,! second elem5t ( erosion is transportation4 ,! transportation ( me*anical s$im5t is to be di/+ui%$ f ! transportation ( mat]ials 9 solution4 ,9 s f> z m9]al matt] is dissolv$ x becomes1 s f> z fl[age is conc]n$1 a "p ( ! /ream4 ,if ! quantity dissolv$ 7 l>ge x might influ5ce ! mobility ( ! wat]1 b ! am\nt is usually too slight to influ5ce ! fl[ s5sibly4 ,! s$im5t transport$ by a /ream is ei!r roll$ along its bottom or c>ri$ 9 susp5sion at "s high] level4 ,! co>s] mat]ials 7gravel & s&7 are c>ri$ *iefly 9 ! =m] position1 & ! f9] 7silt & mud7 l>gely 9 ! latt]4 ,transport+ p[] & velocity4--,! transport+ p[] ( runn+ wat] dep5ds on its velocity4 ,! =mula express+ ! relations betwe5 !m is z foll[s3 ,transport+ p[]1 t1 v>ies z ! six? p[] ( velocity1 v1 7tv72 t is1 d\bl+ ! velocity ( ! /ream increases its transport+ p[] #fd-;fold4 ,/rictly speak+1 ?is means t if a /ream ( giv5 velocity is j able to move a /one ( a giv5 size1 a /ream ) d\ble t velocity w be j able to move a /one ( ! same %ape #fd times z l>ge z ! fir/4 ,?is may be graphically illu/rat$ z foll[s3 ,let a curr5t be suppos$ j able to move ! cube a 7,fig4 #ig74 ,if ! curr5t be d\bl$1 twice z mu* wat] w /rike ! same surface ) twice ! =ce 9 ! same "t2 t is1 ! =ce ex]t$ on ! cube a w be quadrupl$4 ,x w1 !re=e1 be able n only to move ! "o cube1 b x w be able to move ?ree o!r cubes 7b1 c1 & d7 besides 7,fig4 #ih74 ,! same curr5t aga9/ any o!r equal surface w\ld also be able to move f\r small cubes1 & !re are sixte5 su* surfaces on ! face ( ! l>ge cube 7,fig4 #ii74 ,x foll[s t ! dim5sion ( ! cube :i* ! /ream ) ! d\bl$ velocity c move is f\r times z great z t ( ! cube :i* ! orig9al curr5t c\ld move1 & ! cubical cont5ts ( su* a cube is #fd times z great z t ( ! fir/ 7#fd #b7 7,fig4 #ii74 ,swift /reams1 !re=e1 h enorm\sly great] p[] ( transportation ?an sluggi% ones4 ,x does n necess>ily foll[ t transportation keeps pace ) transport+ p[]2 t dep5ds on ! accessibility ( mat]ials suitable = transportation4 ,a /ream ( great transport+ p[]1 l ! ,niag>a at its rapids1 may c>ry little s$im5t1 because !re is little to be _h4 ,! velocity ( a /ream dep5ds *iefly on ?ree elem5ts--its gradi5t1 its volume1 & its load1 7i4e41 ! s$im5t x is mov+74 ,! high] ! gradi5t ! great] ! volume1 & ! less ! load ! great] ! velocity4 ,! relation betwe5 gradi5t & velocity is evid5t2 t betwe5 volume & velocity is illu/rat$ by e /ream 9 "t ( flood1 :5 its rate ( fl[ is greatly increas$4 ,! relation betwe5 velocity & load is less obvi\s1 b none ! less def9ite4 ,e p>ticle ( s$im5t c>ri$ by a /ream makes a draught on its en]gy1 & en]gy exp5d$ 9 ?is way r$uces ! velocity4 ,! draught on a /ream's en]gy ( a p>ticle c>ri$ 9 susp5sion is measur$ by its mass into ! di/ance x w\ld fall 9 a unit ( "t 9 /ill wat]4 ,x foll[s t a l>ge p>ticle makes a /rong] draught on a /ream's en]gy ?an ! same am\nt ( mat]ial 9 small] pieces4 ,x foll[s also t ! comm9ution ( s$im5t facilitates transportation 9 mu* m ?an a simple ratio1 = n only c a giv5 am\nt ( en]gy c>ry m f9e mat]ial ?an co>se1 b a l>g] proportion ( a /ream's en]gy c be utiliz$ 9 ! transportation ( ! f9e4 ,illu/ration3 ,figs4 #ig-ii4--;,diagrammatic repres5tation ( ! effect ( increas$ velocity on transport+ p[]4 ,h[ s$im5t is c>ri$4--,co>se mat]ials1 su* z gravel /ones1 are roll$ along ! bottoms ( ! swift /reams :i* c>ry !m4 ,_! movem5t is effect$ by ! impact ( wat]4 ,! same is true to a l>ge ext5t ( s& gra9s1 especially if !y be co>se4 ,s f> z conc]ns ! mat]ial roll$ along ! bottom x is to be not$ t a /ream's transport+ p[] is dep5d5t on ! velocity ( ! wat] at its bottom4 ,?is is mu* less ?an ! surface1 or ev5 ! av]age velocity4 ,! p>ticles ( f9e s$im5ts1 su* z silt & mud1 are frequ5tly c>ri$ by /reams q above _! bottoms1 z %[n by ! roil9ess ( _m /reams4 ,a p>ticle ( mud is usually a small bit ( m9]al matt]1 ! specific gravity ( :i* is two or ?ree times t ( wat]4 ,:y does x n s9k ?r\gh ! wat] & come to re/ at ! bottom ( ! /ream1 or suff] transportation z ! gravel does8 ,illu/ration3 ,fig4 #ajj4--;,diagram to illu/rate ! relative /r5g? ( ! two =ces act+ on a p>ticle 9 susp5sion4 ,! arr[s repres5t ! relative /r5g? ( ! two =ces :5 ! /ream's velocity is #e miles p] h\r4 ,no acc\nt is tak5 9 ! diagram ( ! viscosity ( ! wat]1 or ( ! accel]ation ( velocity ( fall4 ,a p>ticle ( s$im5t 9 runn+ wat] is obvi\sly subject to two =ces1 t ( ! curr5t :i* t5ds to move x ne>ly horizontally d[n-/ream1 & t ( gravity :i* t5ds to c>ry x to ! b$ ( ! /ream4 ,9 ,fig4 #ajj1 ! arr[s ab & ac repres5t respectively ! relative =ce ( gravity & a curr5t ( #e miles p] h\r4 ,z a result ( ^! two =ces ! p>ticle w\ld t5d to desc5d 9 ! g5]al direction ( ad1 a l9e :i* repres5ts ! resultant ( ^! =ces1 ?\gh n ! exact pa? :i* a p>ticle act$ on by !m w\ld take 9 wat]4 ,if a riv] 7 ! simple /raight=w>d curr5t :i* x is popul>ly ?\ght to be1 a p>ticle 9 susp5sion w\ld rea* its bottom 9 ! "t x w\ld take to s9k ?r\gh an equal dep? ( /ill wat]1 = ! desc5t w\ld be none ! less c]ta9 & none ! less prompt because ( ! =w>d movem5t ( ! wat]4 ,! curr5t w\ld simply be a factor 9 det]m9+ ! position ( ! p>ticle :5 x rea*$ ! bottom1 n ! "t ( rea*+ x4 ,v f9e p>ticles1 l ^? ( clay1 ?\gh hav+ ! same specific gravity z gra9s ( s&1 w\ld s9k less readily ?an co>s] ones1 because !y expose l>g] surfaces1 relative to _! mass1 to ! wat] ?r\gh :i* !y s9k4 ,b ev5 su* p>ticles1 unless ( extraord9>y f95ess1 w\ld pres5tly rea* ! bottom if act$ on only by a horizontal curr5t & gravity4 ,s9ce ev5 s$im5t :i* is n ( exce$+ f95ess is kept 9 susp5sion x is cle> t "s o!r factor is involv$4 ,?is is f\nd1 9 "p at lea/1 9 ! subord9ate upw>d curr5ts 9 a /ream4 ,:]e a b[ld] occurs 9 ! b$ ( a /ream 7,fig4 #aja7 ! wat] :i* /rikes x is 9 "p =c$ up ov] x4 ,if !re be _m b[ld]s ! process is frequ5tly repeat$1 & ! numb] ( upw>d curr5ts is great4 ,any r\ghness w s]ve ! same purpose1 & e /ream's b$ is r\gh to a great] or less ext5t4 ,:]e !re are r\ghnesses at ! sides ( a *annel1 curr5ts are />t$ :i* fl[ f !m t[>d ! c5t]4 ,! v>y+ velocities ( ! diff]5t p>ts ( a /ream s]ve a simil> purpose4 ,! curves 9 a riv] t5d to give ! wat] a rotatory movem5t4 ,a riv] is !re=e to be look$ ^u n z a s+le /raight=w>d curr5t1 b z a multitude ( curr5ts1 "s ris+ f ! bottom t[>d ! top1 "s desc5d+ f top to bottom1 "s div]g+ f ! c5t] t[>d ! sides1 & "s conv]g+ f ! sides t[>d ! c5t]4 ,! exi/5ce ( ^! subord9ate curr5ts is (t5 evid5t f ! boil+ & eddy+ readily se5 9 _m /reams4 ,x is1 ( c\rse1 true t ! sum ( ! upw>d curr5ts is always less ?an ! sum ( ! d[nw>d1 s t ! aggregate motion ( ! wat] is d[n slope2 b x is also true t m9or upw>d curr5ts are common4 ,s$im5t 9 susp5sion is held up *iefly by su* curr5ts1 :i*1 locally & tempor>ily1 ov]come ! effect ( gravity4 ,! p>ticles 9 susp5sion are con/antly t5d+ to fall1 & frequ5tly fall+2 b be=e !y rea* ! bottom _m ( !m are seiz$ & c>ri$ upw>d by ! subord9ate curr5ts1 only to s9k & be c>ri$ up aga94 ,ev5 if !y rea* ! bottom1 z !y frequ5tly d1 !y may be pick$ up aga94 ,x is probable t e p>ticle ( s$im5t ( su* size t x w\ld s9k readily 9 /ill wat] is dropp$ & pick$ up _m times 9 ! c\rse ( any long riv] j\rney1 & its p]iods ( re/ (t5 exce$ its p]iods ( movem5t4 ,illu/ration3 ,fig4 #aja4--;,diagram to illu/rate ! effect ( b[ld]s1 a & b1 9 a /ream's b$ on ! curr5ts ( wat] imp++ aga9/ !m4 ,indep5d5tly ( ! subord9ate curr5ts1 ! diff]5t velocities ( ! diff]5t p>ts ( a /ream t5d to keep mat]ials 9 susp5sion by ex]t+ diff]5t pressures on ! diff]5t sides ( susp5d$ p>ticles4#df ,riv] ice sometimes facilitates ! transportation ( dbris :i* ! wat] alone c\ld n c>ry4 ,! ice freezes to b[ld]s 9 ! banks ( ! /reams1 to ^? :i* are p>tially subm]g$1 & sometimes to ^? altoge!r subm]g$ b5ea? slight dep?s ( wat]4 ,:5 ! ice breaks up 9 ! spr+ su* b[ld]s1 buoy$ up by ! ice1 may be float$ f> d[n ! /ream4 ,! influ5ce ( ice 9 ?is connection is mo/ consid]able 9 high latitudes1 b x is ( consequ5ce z f> s\? z ,virg9ia1 :]e ! riv] deposits sometimes conta9 b[ld]s :i* ! unaid$ /reams c\ld n h c>ri$4 ,gr\nd ice sometimes =ms ab\t b[ld]s 9 ! bottoms ( /reams1 especially 9 ! quiet pools ( turbul5t riv]s1 & floats !m to ! surface be=e ! surface itself is froz54#dg ,9 ! floods ( spr+ riv]s (t5 spread _! ice widely ov] _! flood-pla9s4 ,x is sometimes mass$ 9 con/rict$ portions ( valleys s z to =m great dams1 ! break+ ( :i* is att5d$ ) great de/ruction4 ,corrasion4 ,abrasion4--,! we> effect$ by runn+ wat] is corrasion4 ,s long z ! mat]ials to be c>ri$ away are incoh]5t x is easy to see h[ runn+ wat] picks !m up & c>ries !m =w>d4 ,! wat] :i* ga!rs 9 ! depressions on ! slope ( a cultivat$ field ga!rs e>?y matt] f ! surface ov] :i* x passes1 ev5 be=e x is conc5trat$ into rills1 & ! rills cont9ue ! process4 ,?us ! loose mat]ials ( ! surface are ga!r$ at ! v s\rces ( ! /reams1 & ! am\nt ( s$im5t 9 ! wat] aft] a heavy %[]1 ev5 at ! head ( ! /ream1 may be great4 ,! run-(f f ! slopes ( any valley 9 any "p ( its c\rse likewise br+s s$im5t to ! /ream1 :i* ga!rs m f its b$ :]eev] x fl[s ) suffici5t velocity ov] incoh]5t mat]ial4 ,/reams also und]cut _! banks1 & receive new load f ! fall ( ! ov]hang+ mat]ial4 ,by f> ! l>g] "p ( ! s$im5t acquir$ by a normal /ream is made up ( mat]ial loos5$ 9 advance by ! processes ( wea!r+4 ,! /ream1 or ! wat]s :i* get toge!r to make ! /ream1 f9d !m ready-made2 b riv]s frequ5tly we> rock :i* is n wea!r$1 = ! pr9cipal valleys ( ! e>?'s surface are cut 9 solid rock1 & _m ( !m 9 rock ( exce$+ h>dness4 ,h[ does ! /ream we> ! solid rock8 ,:5 a /ream fl[s ov] a rock b$1 ! we> :i* x accompli%es dep5ds *iefly on ! "* ( ! rock1 ! velocity ( ! /ream1 & ! load x c>ries4 ,if ! rock be /ratifi$ & 9 ?9 lay]s1 & if ^! ?9 lay]s be brok5 by num]\s jo9ts at high angles to ! /ratification planes1 ! impact ( ! wat] ( a cle> /ream ( ev5 mod]ate /r5g? may be effective 9 dislodg+ bits ( ! rock4 ,?is condition ( ?+s is (t5 se5 :]e /reams run on b$s ( %ale or slate4 ,if ! rock be h>d & )\t b$d+-planes & jo9ts1 or if its lay]s be ?ick & its jo9ts few1 cle> wat] w be mu* less effective4 ,if ! surface ( ! rock be r\gh1 ! me*anical action ( a swift /ream ( cle> wat] might /ill produce "s effect on x2 b if massive h>d rock pres5ts a smoo? surface to a cle> /ream1 ! me*anical effect ( ev5 a swift curr5t is slight4 ,?is g5]al pr9ciple is illu/rat$ by ! ,niag>a ,riv]4 ,j above ! falls ! curr5t is swift4 ,:5 ! riv] is ess5tially free f s$im5t1 ! surface ( ! lime/one ne> ! bank b5ea? x is sometimes di/9ctly gre5 f ! pres5ce ( ! "o-cell$ plants 7fre%-wat] alg7 :i* gr[ ^u x4 ,! :ole =ce ( ! mighty torr5t is n able to sweep !m f _! moor+s4 ,7 ! /ream suppli$ ) a ti! ( ! s& :i* x is capable ( c>ry+1 x w\ld n take _m h\rs1 & p]haps n _m m9utes1 to remove ! la/ trace ( vegetation4 ,?is illu/ration furni%es a clue to ! me?od by :i* ! erosion ( solid rock 9 a /ream's b$ is effect$4 ,x has be5 se5 t ! +a!r+ wat]s :i* make a /ream (t5 h abundant s$im5t be=e !y rea* well-def9$ /ream *annels1 & t ! /reams cont9ue to ga!r s$im5t :]eev] _! b$s are compos$ ( mat]ial :i* is readily deta*$4 ,! s$im5ts :i* ! /ream c>ries are ! tools ) :i* x works4 ,)\t !m x is relatively impot5t1 s f> z ! abrasion ( solid rock is conc]n$2 ) !m1 x may we> any rock ov] :i* x passes 7,fig4 #ajb74 ,we h next to inquire ! me?ods by :i* runn+ wat] uses its tools 9 ! excavation ( valleys4 ,:5 gravel is roll$ along 9 ! *annel ( a /ream !re is friction betwe5 x & ! b$ ov] :i* x moves4 ,if ! pebbles be z h>d z ! b$ ov] :i* !y are roll$ _! movem5t mu/ result 9 its we>1 & ev5 if !y be s(t] m or less we> takes place4 ,z ! mov+ /ones we> ! rock ( ! /ream's b$ !y are !mselves worn by impact ) x & ) "o ano!r4 ,9 all cases ! s(t] mat]ial suff]s ! m rapid we>4 ,! fir/ effect ( we> on mat]ials 9 transportation is ! r$uction ( _! rugosities ( surface4 ,! project+ po9ts & %>p angles are worn (f1 & ! /ones are r$uc$ to r\nd$ wat]-worn =ms4 ,! p>ticles brok5 (f make gra9s ( s&1 or1 if v f9e1 p>ticles ( silt or mud4 ,ev5 aft] a /one has be5 r\nd$ x is subject to fur!r we> & r$uction1 & 9 ! c\rse ( "t may be lit]ally worn out4 ,! s$im5t c>ri$ 9 susp5sion1 z well z t roll$ along ! bottom1 may we> ! rock b$ ( a /ream4 ,:5 a gra9 ( s& 9 susp5sion escapes f an upw>d mov+ curr5t x may n s9k quietly4 ,if x be caught by a d[nw>d curr5t x may be made to /rike a bl[ on ! b$ ( ! /ream1 & ! effect ( ! bl[ is to we> ! surface :i* receives x4 ,! l>g] ! gra9 & ! /rong] ! curr5t ! great] ! we>4 ,illu/ration3 ,fig4 #ajb4--,"s ( ! tools ) :i* a /ream works4 ,! cobbles & b[ld]s h be5 %ift$ by ! /ream 9 its fl[4 ,o!r /ones & b[ld]s n[ 9 transit cause ! ripples 9 ! /ream4 ,! ,*elan ,riv]1 ,wa%41 j above its junction ) ! ,columbia4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,! ceaseless repetition ( ! bl[s /ruck by ! mat]ial 9 susp5sion1 or roll$ on its bottom1 h\r aft] h\r1 day aft] day1 & ye> aft] ye>1 w accompli% s5sible results4 ,9 ! long c\rse ( ! ages ?is process has excavat$ deep valleys4 ,concomitant processes are l>gely conc]n$ 9 mak+ valleys wide1 b ! dep? ( valleys cut 9 solid rock is *iefly ! result ( ! impact & friction ( ! s$im5t 9 transportation4 ,! we> effect$ 9 ?is way is n proportional to ! numb] ( bl[s /ruck4 ,s9ce e pebble & e gra9 ( s& c>ri$ dim9i%es ! velocity ( a /ream1 & s9ce ) dim9i%$ velocity ! =ce ( ! bl[s /ruck is dim9i%$1 x foll[s t ! bl[s may become s weak1 z ! result ( _! multiplication1 z to be ineffective4 ,! l>g] ! load1 !re=e1 :i* ! /ream c>ries1 ! m ! tools ) :i* x has to "w1 b ! less effectively c x use !m2 & ! load may be s f> increas$ z to de/roy its corrasive p[] altoge!r4 ,on ! o!r h&1 ! small] ! load ( ! /ream ! great] its velocity & ! m effectively w its tools be us$2 b _! numb] may be s f> r$uc$ t _! aggregate effect is slight4 ,to accompli% ! greate/ results on a b$ ( solid rock a /ream mu/ h tools to "w )1 b mu/ n be s heavily burd5$ z to int]f]e ) its effective use ( !m4 ,:atev] ! cause ( _! unequal velocities swift & sl[ /reams corrade _! valleys diff]5tly4 ,! erosion ( a swift /ream is *iefly at ! bottom ( its *annel4 ,! sluggi% /ream l[]s its *annel less rapidly1 :ile lat]al erosion is relatively m important4 ,! result is t sl[ /reams increase ! wid? ( _! valleys m ?an ! dep?1 :ile swift /reams increase ! dep? m ?an ! wid?4 ,x foll[s t sl[ /reams develop flats1 :ile swift ones d n4 ,n only is a sl[ /ream m likely to h a flat1 & !re=e a bett] *ance to me&]1 b x is m likely to take advantage ( opportunities 9 ?is l9e1 = a sl[ /ream gets out ( ! way = su* ob/acles z x may enc\nt]1 :ile a swift /ream is mu* m likely to get ob/acles out ( its way4 ,special phases ( corrasion are introduc$ :]e wat]falls & o!r peculi>ities dep5d5t on inequalities ( rock resi/ance occur4 ,solution4--,9 mo/ cases ! solution effect$ by a /ream is mu* less important ?an its me*anical "w4 ,only :5 conditions are unfavorable to ! latt]1 is solution ! *ief factor 9 ! excavation ( a valley4 ,?is may be ! case :]e a /ream's b$ is ov] soluble rock1 su* z lime/one1 & :]e ! /ream is cle>1 or its gradi5t s l[ t its curr5t is sluggi%4 ,! solv5t p[] ( wat] is n influ5c$ by ! pres5ce ( s$im5t1 ?\gh ! pres5ce ( s$im5t (f]s ! wat] a great] surface on :i* to "w4 ,,conditions ,,affect+ ,,! ,,rate ,,( ,,erosion4 ,9 consid]+ ! rate ( erosion1 bo? ! "w ( ! /ream 9 its valley & t ( ! g5]al run-(f are to be consid]$4 ,! conditions :i* favor ! mo/ rapid erosion 9 a /ream's *annel are n necess>ily ^? :i* det]m9e mo/ rapid degradation 9 ! bas9 outside ( ! valley4 ,! ,influ5ce ( ,declivity4 ,9 g5]al ! great] ! declivity ! m rapid ! rate ( erosion1 :e!r 9 ! /ream's *annel or on ! slopes above x4 ,! tru? ( ?is conclusion is illu/rat$ by ! great erosive p[] ( swift /reams z comp>$ ) sl[ ones4 ,x does n foll[1 h[ev]1 t high declivity favors ea* elem5t ( erosion4 ,! effect ( declivity on wea!r+ is f> f simple4 ,= example1 great declivity1 by all[+ m ( ! ra9fall to fl[ (f ov] ! surface1 & by caus+ x to fl[ (f m promptly1 re/ricts ! "w ( solution1 & !re=e ( decomposition1 bo? at ! surface & b5ea? x4 ,high declivity is also unfavorable to ! gr[? ( vegetation1 & s to ! w$ge-"w ( roots4 ,on ! o!r h&1 a giv5 am\nt ( w$ge-"w ( roots & ice is m effective :]e ! slope is /eep ?an :]e x is g5tle1 = su* mat]ials z are loos5$ desc5d ! slopes m readily4 ,! prompt removal ( wea!r$ mat]ials1 by expos+ fre% surfaces ( rock1 accel]ates wea!r+4 ,! total am\nt ( wea!r+ may !re=e n be dim9i%$ by ! increase ( slope1 ev5 ?\gh c]ta9 ( its processes are h9d]$4 ,! effect ( high declivity on transportation1 ! second elem5t ( erosion1 is too pat5t to ne$ explanation4 ,corrasion likewise is favor$ by high declivity1 = ! abrasive p[] ( a /ream increases z ! squ>e ( its velocity4 ,) corrasive p[] increas$1 corrasion w also be increas$ if ! wat] has tools to "w )4 ,s9ce high declivity greatly increases bo? ! transport+ & ! corrasive p[] ( runn+ wat]1 & favors c]ta9 elem5ts ( wea!r+1 x is cle> t ! aggregate effect ( high declivity is to favor erosion1 :e!r 9 ! *annel ( ! /ream or on ! g5]al surface ( its dra9age bas94 ,! ,influ5ce ( ,rock4 ,! physical con/itution1 ! *emical composition1 & ! /ratigraphy ( a rock =mation1 influ5ce ! rate at :i* x may be brok5 up & c>ri$ away4 ,cla/ic or fragm5tal rocks are usually /ratifi$ & made up ( cem5t$ pebbles 7conglom]ate71 s& gra9s 7s&/one71 or p>ticles ( mud 7%ale74 ,igne\s rocks1 su* z granite1 are massive in/ead ( /ratifi$1 & are usually made up ( great numb]s ( int]lock+ cry/als :i* b9d "o ano!r toge!r4 ,"s cry/all9e rocks1 su* z s*i/s1 ?\gh n /ratifi$1 possess cleavage1 :i* has mu* ! effect ( /ratification1 s f> z erosion is conc]n$4 ,all rocks are affect$ by sy/ems ( m or less ne>ly v]tical cracks call$ jo9ts4 ,all ^! /ructures h _! influ5ce ^u ! rate ( degradation4 ,physical con/itution4--,cla/ic rocks may be firmly cem5t$1 or _! con/itu5ts may be loosely b\nd toge!r4 ,! less ! coh]5ce ! m ready ! dis9tegration1 & ! f9] ! p>ticles ! m easily are !y c>ri$ away4 ,:5 ! p>ticles 9 transportation are angul> !y effect m we> on ! b$ ov] :i* !y move1 & on "o ano!r1 ?an :5 !y are r\nd4 ,! diff]5ce is great :]e ! p>ticles are l>ge1 & little :]e !y are v small4 ,if ! mat]ials c>ri$ be h>d] ?an ! b$ ov] :i* !y pass1 corrasion ( ! latt] is favor$4 ,*emical composition4--,some?+ also dep5ds on ! *emical composition ( ! rock1 s9ce ?is affects its solubility1 & !re=e its rate ( decomposition4 ,! m soluble ! rock ! l>g] ! proportion ( x :i* w be tak5 away 9 solution2 b x does n foll[ t ! mo/ soluble rock w be mo/ rapidly erod$1 s9ce ! rate ( erosion dep5ds on abrasion z well z solution1 & a rock :i* is readily soluble1 z rocks g1 may be less easily abrad$ ?an a rock :i* is made ( discrete & insoluble p>ticles b\nd toge!r by a soluble cem5t4 ,9 su* rocks1 = example a s&/one 9 :i* ! gra9s are cem5t$ toge!r by lime c>bonate1 ! solution ( ! cem5t sets free a consid]able quantity ( s&1 s t a small am\nt ( solution prep>es a l>ge am\nt ( s$im5t = removal4 ,a /ream might cut its valley mu* m rapidly 9 su* a s&/one ?an 9 a compact lime/one1 ?\gh ! latt] is1 z a :ole1 ! m soluble4 ,! con/itu5t m9]als ( cry/all9e rocks resi/ solution & decay unequally1 & :5 any "o is dissolv$ or decompos$ ! rock crumbles & ! less soluble con/itu5ts are ready = removal by me*anical means4 ,s long z ! mat]ial loos5$ by dis9tegration is remov$1 *emical het]og5eity favors erosion2 b if ! loos5$ dbris is n remov$ erosion is n favor$ by *emical het]og5eity4 ,9 su* a case erosion w\ld be mo/ rapid :]e ! rock 0 mo/ soluble4 ,/ructure4--,! /ructure ( ! rock has mu* to d ) ! rate ( its erosion4 ,o!r ?+s be+ equal1 /ratifi$ rock is m readily erod$ ?an massive rock1 s9ce /ratification-planes are planes ( cleavage1 & !re=e ( weakness4 ,tak+ advantage ( ^! planes ! wat] has less break+ to p]=m to r$uce ! mat]ial to a transportable condition4 ,= ! same reason a ?9-b$d$ =mation is m easily erod$ ?an a ?ick-b$d$ "o4 ,illu/ration3 ,figs4 #ajc & #ajd4--;,diagrams to illu/rate ! fact t a /ream crosses _m m cleavage-planes :5 ! b$s ( rock are incl9$ ?an :5 !y are horizontal4 ,! b$s ( /ratifi$ rock may be horizontal1 v]tical1 or incl9$1 & incl9$ /rata may /& at any angle betwe5 horizontality & v]ticality4 ,9 indurat$ =mations ! rate ( erosion is influ5c$ bo? by ! position ( ! /rata & by ! relation ( ! direction ( ! fl[+ wat] to _! dip & /rike4 ,on ! :ole ! /rata :i* are horizontal1 or b slightly incl9$1 are probably less favorable = rapid erosion ?an ^? :i* are v]tical or incl9$ at consid]able angles4 ,?is is at lea/ true :]e ! lay]s are ( uni=m h>dness & ! jo9ts infrequ5t4 ,horizontal /rata expose few] cleavage planes to ! wat] fl[+ ov] !m ?an /rata 9 any o!r position4 ,9 ,fig4 #ajc ! /ream :i* has ! pr(ile ad crosses b$d+-planes at b & c4 ,9 ,fig4 #ajd1 :]e ! b$s dip up-/ream1 _m m division-planes are cross$ 9 ! same di/ance4 ,s9ce b$d+-planes are planes ( weakness1 x foll[s t horizontal & ne>ly horizontal /rata are n1 "u ord9>y conditions ( erosion1 9 a position favorable = mo/ rapid we>4 ,:5 /rata are horizontal1 x makes no diff]5ce :i* way ! /ream runs1 = ! curr5t su/a9s ! same relation to ! cleavage-planes :atev] its c\rse4 ,9 ! case ( incoh]5t mat]ial ! position ( ! b$s1 or ev5 _! exi/5ce1 has little influ5ce on ! rate ( erosion4 ,su* =mations are weak 9 all directions1 n simply along b$d+-planes4 ,illu/ration3 ,fig4 #aje4--;,diagram to illu/rate ! v>i\s relations a /ream may su/a9 to ! outcrop ( v]tical lay]s ( rock4 ,illu/ration3 ,fig4 #ajf4--;,diagram to illu/rate ! v>i\s relations a /ream may su/a9 to ! outcrops ( incl9$ lay]s ( rock4 ,:5 ! /rata are v]tical1 ?ree di/9ct cases may arise 7,fig4 #aje74 ,! /ream may fl[ 7#a7 ) ! /rike 7aa72 7#b7 at "r angles to ! /rike 7bb72 or 7#c7 oblique to x 7cc7 at any angle :atsoev]4 ,x is p]haps n possible to say :i* ( ^! positions is mo/ favorable = erosion1 = ! "* ( ! rock1 ! ?ickness ( its lay]s1 its ability to /& ) /eep slopes1 & ! /r5g? ( ! curr5ts conc]n$1 w\ld influ5ce ! result4 ,a /ream :i* fl[s at "r angles to ! /rike 7bb1 ,fig4 #aje7 w\ld cross m cleavage-planes 9 a giv5 di/ance ?an a /ream fl[+ 9 any o!r direction1 & w\ld /rike ! outcropp+ edges ( lay]s at ! angle ( greate/ advantage4 ,a /ream fl[+ along ! /rike 7aa71 on ! o!r h&1 has bett] opportunity to s9k its *annel on cleavage-planes1 & ! curr5t oblique to ! /rike 7cc71 has "s ( ! advantages ( ea* ( ! o!rs4 ,:5 ! /rata are incl9$ five cases may arise4 7#a7 ,! /ream may be p>allel to ! /rike 7aa1 ,fig4 #ajf71 :5 x makes no diff]5ce :i* way ! curr5t fl[s2 x may be at "r angles to ! /rike 7bb71 & 7#b7 fl[+ ) ! dip 7t[>d b71 or 7#c7 aga9/ x 7t[>d b72 x may be oblique to ! /rike1 & fl[+ 7#d7 9 ! g5]al direction ( dip 7t[>d c72 or 7#e7 9 ! opposite direction 7t[>d c74 ,z be=e1 ! /ream fl[+ at "r angles to ! /rike w\ld cross ! l>ge/ numb] ( lay]s 9 a giv5 di/ance1 & s h an opportunity to take advantage ( m cleavage-planes ?an a /ream 9 any o!r position4 ,b 9 ! case ( incl9$ /rata a new elem5t ent]s into ! problem4 ,:5 ! /ream fl[s p>allel to ! /rike1 ! valley :i* is 9 process ( deep5+ is n sunk v]tically1 b is %ift$ m or less 9 ! direction ( ! dip 7,fig4 #ajg74 ,?is is call$ monocl9al %ift+4 ,! result is t !re is a con/ant t5d5cy to und]m9e 7sap7 ! valley bluff on ! d[n-dip side1 & ?is process ( sapp+ w1 accord+ to its rate1 accel]ate ! gr[? ( ! valley1 especially 9 wid?4 ,monocl9al %ift+ is favor$ by ! pres5ce ( a h>d lay] 7,h71 z %[n 9 ,fig4 #ajg1 if ?is /ratum is ! b$ ( ! /ream4 ,illu/ration3 ,fig4 #ajg4--;,diagram to illu/rate monocl9al %ift+4 ,! valley abc1 z se5 9 cross-section1 becomes deb1 z ! /ream l[]s its *annel4 ,9 ! second & ?ird cases m5tion$ above1 ! only diff]5ce is 9 ! angle at :i* ! curr5t /rikes ! outcropp+ edges ( lay]s & lam94 ,! me*anical advantage is ) ! /ream :i* fl[s ) ! dip4 ,9 ! f\r? & fif? cases some?+ w dep5d on ! angle :i* ! /ream's c\rse makes ) ! /rike4 ,9 all ^! cases1 z 9 ^? :]e ! /rata are v]tical1 mu* w dep5d on ! ?ickness & resi/ance ( ! lay]s & on ! /r5g? ( ! curr5ts conc]n$4 ,! ,influ5ce ( ,climate4 ,climate has bo? a direct & an indirect effect on erosion4 ,its direct influ5ce is ?r\gh precipitation1 evaporation1 *anges ( temp]ature1 & w9d2 its indirect1 ?r\gh vegetation4 ,l declivity & rock /ructure1 climate does n affect all elem5ts ( erosion equally4 ,! *ief elem5ts ( climate are temp]ature1 moi/ure1 & atmosph]ic movem5ts2 ! pr9cipal factors :i* influ5ce x are latitude1 altitude1 di/ance f ! sea1 direction ( prevail+ w9ds1 & topographic relations4 ,! effects ( v>iations 9 temp]ature on rock wea!r+ h already be5 discuss$ 7p4 #dc74 ,!y are *iefly me*anical1 & are se5 at _! be/ :]e ! daily range is great4 ,high temp]ature favors *emical action1 & ! wea!r+ ( rock by decomposition is at its be/ 9 ! pres5ce ( abundant moi/ure 9 regions :]e ! temp]ature is uni=mly high4 ,fur!rmore1 a w>m moi/ climate favors ! gr[? ( vegetation1 ! decay ( :i* supplies ! wat] ) organic acids :i* greatly increase its solv5t p[]4 ,! climatic conditions favor+ me*anical wea!r+ are !re=e diff]5t f ^? favor+ *emical wea!r+4 ,high temp]ature & abundant moi/ure & vegetation are f\nd 9 _m tropical regions1 & "h ! rock is (t5 decompos$ to great] dep?s1 on ! :ole1 ?an 9 high latitudes4 ,h[ f> ?is is ! result ( rapid wea!r+1 & h[ f> ( sl[ removal1 due 9 "p to ! protective influ5ce ( ! plants1 _c be affirm$4 ,if ! wea!r$ mat]ial is n remov$1 x w pres5tly become a mantle ?ick en\gh to ret>d ! processes :i* br\ght x into exi/5ce4 ,s long z ! wat] ( ! surface & t 9 ! soil rema9s unfroz51 temp]ature affects nei!r corrasion nor transportation4 ,b 9 middle & high latitudes ! surface is froz5 = "s "p ( ea* ye>4 ,dur+ ?is "t corrasion is at a m9imum1 = al?\gh ! /reams cont9ue to fl[ !re is relatively little wat] runn+ ov] ! surface outside ! dra9age *annels1 & t little is relatively ineffective4 ,"u "s conditions1 !re=e1 temp]ature affects bo? corrasion & transportation4 ,! humidity ( ! atmosph]e has an influ5ce ev5 m important ?an t ( temp]ature on ! rate ( erosion1 & its influ5ce is ex]t$ on ea* ( ! elem5ts ( t complex process4 ,a moi/ atmosph]e favors oxidation1 c>bonation1 hydration1 & ! gr[? ( vegetation1 all ( :i* promote c]ta9 phases ( rock wea!r+4 ,on ! o!r h&1 humidity t5ds to prev5t sudd5 & consid]able v>iations 9 temp]ature1 ?us *eck+ ! wea!r+ effect$ by ?is means4 ,precipitation1 ! mo/ important s+le factor 9 det]m9+ ! rate ( erosion1 is dep5d5t on atmosph]ic humidity4 ,its am\nt1 its k9d 7ra9 or sn[71 & its di/ribution 9 "t1 are ! elem5ts :i* det]m9e its effectiv5ess 9 any giv5 place4 ,o!r ?+s be+ equal ! great] ! am\nt ( precipitation ! m rapid ! corrasion & transportation4 ,mu*1 h[ev]1 dep5ds on its di/ribution 9 "t4 ,a giv5 am\nt ( ra9fall may be di/ribut$ equally ?r\gh ! ye>1 or x may fall dur+ a wet season only4 ,! maximum inequality ( di/ribution w\ld occur if all ! ra9fall ( a giv5 p]iod 7 conc5trat$ 9 a s+le %[]4 ,) su* conc5tration ! volume ( wat] fl[+ (f ov] ! surface imm$iately aft] ! d[n-p\r w\ld be great] ?an "u any o!r conditions ( precipitation1 & s9ce velocity is increas$ ) volume1 & erosive p[] ) velocity1 x foll[s t ! erosive p[] ( a giv5 am\nt ( wat] w\ld be great] "u ^! circum/ances ?an "u any o!r4 ,fur!rmore1 a l>g] proportion ( ! precipitation w\ld run (f ov] ! surface "u ^! circum/ances ?an "u any o!r1 = less ( x w\ld s9k b5ea? ! surface & less w\ld be evaporat$4 ,if erosive p[] & rate ( erosion 7 equal t]ms1 ?is w\ld !re=e be ! condition = greate/ erosion2 b erosive p[] & rate ( erosion d n always correspond4 ,if ! wat] fall+ 9 ?is way c\ld get hold ( all ! mat]ial x c\ld c>ry1 extreme conc5tration ( precipitation w\ld be ! condition favorable = mo/ rapid erosion4 ,b if ! am\nt ( available mat]ial = transportation is slight1 a l>ge "p ( ! =ce ( ! wat] c\ld n be utiliz$ 9 erosion4 ,x foll[s t if !re 7 a l>ge am\nt ( dis9tegrat$ mat]ial on ! surface1 erosion w\ld be great] ! great] ! conc5tration ( precipitation4 ,if1 on ! o!r h&1 !re 7 b little dis9tegrat$ mat]ial on ! surface1 frequ5t %[]s1 ) int]v5+ p]iods :5 conditions 7 favorable = wea!r+1 t is1 = prep>+ mat]ial = transportation1 might be m favorable = rapid erosion4 ,:ile ! total en]gy ( runn+ wat] available = erosion "u ^! conditions w\ld be less ?an be=e1 !re might 9 ! long run be m mat]ial = transport2 = wea!r+ 9 ! pres5ce ( moi/ure1 & all t goes ) x1 might be m effective 9 prep>+ mat]ial = transportation1 ?an wea!r+ dur+ ! long p]iods ( dr\ght :i* w\ld occur if ! precipitation 7 conc5trat$ to its maximum4 ,temp]ature favor+1 ! uni=m di/ribution ( moi/ure ?r\gh ! ye> w\ld all[ ! gr[? ( vegetation1 :i*1 al?\gh favor+ "s processes ( wea!r+1 ret>ds erosion 9 g5]al4 ,:ile !re=e x is n possible to say :at di/ribution ( ra9fall favors mo/ rapid erosion )\t kn[+ ! nature ( ! surface on :i* x is to fall1 en\gh has be5 said to %[ t ! problem is by no means a simple "o4 ,"s ( ! mo/ /rik+ phases ( topography develop$ by erosion1 su* z ^? ( ! ,bad ,l&s 7,figs4 #ge to #gh1 & #ajh71 are develop$ :]e ! ra9fall is unequally di/ribut$ 9 "t1 & too slight or too infrequ5t to support abundant vegetation4 ,illu/ration3 ,fig4 #ajh4--;,bad-l& topography develop$ "u conditions ( aridity & unequal di/ribution ( ra9fall4 ,slope ( ,p9al ,m\nta9s1 ,ariz4 7,ransome1 ,u4 ,s4 ,geol4 ,surv47 ,dur+ its fall1 & imm$iately aft]1 ra9 is m effective ?an an equal am\nt ( sn[2 b ! sn[ may be accumulat$ ?r\gh a consid]able p]iod ( ! ye>1 & !n melt$ rapidly1 :5 x has an effect comp>able to t :i* w\ld be produc$ by ! conc5tration ( ! ra9fall into a limit$ p]iod ( ! ye>4 ,if ! gr\nd b5ea? be froz5 :5 ! sn[ melts 7& ?is is (t5 ! case7 ! erosion accompli%$ by ! result+ wat] w be dim9i%$4 ,except 9 dry regions1 :]e w9d-"w sometimes exce$s wat]-"w1 ! movem5ts ( ! atmosph]e are ( less importance directly ?an precipitation 9 det]m9+ ! rate ( erosion4 ,b ev5 9 regions :i* are n arid ! w9ds h mu* to d ) ! rate ( evaporation & ! di/ribution ( ra9fall1 s t _! indirect effect is great4 ,ev5 _! direct effects 9 moi/ climates are n to be lo/ sight (1 = ev5 "h ! surface is sometimes dry en\gh to yield du/ & s&1 & ! uproot+ ( trees s di/urbs ! surface z to make e>?y dbris m accessible to w9d & wat]4 ,:]e trees ga9 prec>i\s foo?olds on /eep slopes1 z !y (t5 d1 !y are likely to be ov]turn$ z soon z !y are l>ge en\gh to (f] consid]able resi/ance to ! w9d1 & 9 ! ov]turn+1 l>ge quantities ( rock are sometimes loos5$ & c>ri$ d[n ! slope by gravity4 ,?is phase ( de/ructive "w is se5 at its be/ on ! walls ( gorges1 :]e trees (t5 fl\ri% until _! tops project above ! rim ( ! valley4 ,?r\gh vegetation1 climate influ5ces erosion 9 ways :i* are easily def9$ qualitatively1 b n quantitatively4 ,bo? by its gr[? 7w$ge-"w ( roots7 & by its decay 7supply+ ,,co1 etc41 to desc5d+ wat]s7 x favors c]ta9 phases ( wea!r+2 b1 on ! o!r h&1 x ret>ds corrasion & transportation bo? by w9d & wat]4 ,?is is well %[n along ! banks ( /reams & on ! faces ( cliffs1 9 clay1 s&1 etc4 ,its aggregate effect is probably unfavorable to erosion by me*anical means1 & favorable to t by *emical processes4 ,illu/ration3 ,fig4 #aji4--;,*>act]i/ic cliffs ( high arid regions4 ,"r wall ( ,snake ,riv] canyon1 ne>ly opposite ! m\? ( ,salmon ,riv]1 ,id4 ,two spr+-=m$ coves1 ) 8,ca/le ,rock0 betwe54 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,erosion 9 high arid regions diff]s f t 9 regions ( abundant ra9fall 9 sev]al ways4 ,x is obvi\s t ! valleys w develop m sl[ly 9 ! =m]1 t !y w rema9 "y long]1 t ! p]iod necess>y = ! dissection ( ! surface is great]1 t ! wat]c\rses w be less num]\s1 & t few] ( !m w h p]man5t /reams4 ,!re are c]ta9 o!r diff]5ces :i* are less obvi\s4 ,if ! arid region be high & compos$ ( het]og5e\s /rata1 ! topography :i* erosion develops is m angul> 7,fig4 #hc7 ?an t ( ! humid region4 ,?is is because !re is less rock decay1 & less vegetation to hold ! products ( decay4 ,! m resi/ant b$s ( rock !re=e come into great] prom95ce1 especially on slopes1 :]e !y develop cliffs 7,figs4 #aji & #aaj74 ,^! g5]al pr9ciples f9d abundant illu/ration 9 ! plateaus ( ! we/]n "p ( ! ,unit$ ,/ates1#dh :]e ! cliffs are by no means conf9$ to ! imm$iate valleys ( ! /reams 7,fig4 #a1 ,pl4 ,,xii74 ,illu/ration3 ,fig4 #aaj4--;,a ,butte4 ,a *>act]i/ic feature ( ! arid plateau region ( ! ,we/4 7,dutton1 ,mono4 ,,ii1 ,u4 ,s4 ,geol4 ,surv47 ,,effects ,,( ,,unequal ,,h>dness4 ,9 ! prec$+ pages incid5tal ref]5ce has be5 made to ! results ( inequalities ( rock resi/ance4 ,?is topic w n[ be consid]$ m fully4 ,rapids & falls4--,return+ = a mom5t to ! hypo!tical isl& ) :i* our /udy ( erosion began1 let a horizontal lay] ( h>d rock be assum$ to run ?r\gh x 7,h1 ,fig4 #aaa74 ,z ! ra9 falls on ! l& & runs (f ov] x1 we> w be less rapid :]e ! h>d lay] comes to ! surface ?an at ! high] or l[] levels4 ,z a result1 ! slope w become /eep] at & bel[ ! outcrop ( ! h>d lay]1 & less /eep imm$iately above x1 z %[n by ab 9 ,fig4 #aaa4 ,"u ^! conditions ! wat] pass+ ov] ! h>d l$ge con/itutes rapids4 ,! increas$ erosion :i* accompanies ! increas$ velocity makes ! rapids m rapid4 ,! process may cont9ue until ! wat] falls1 r ?an fl[s ov] ! h>d lay] 7cd1 ,fig4 #aaa74 ,) cont9u$ ra9fall ! edges ( ! h>d lay]1 toge!r ) ! slopes above & bel[1 w\ld cont9ue to rec$e t[>d ! c5t] ( ! isl&4 ,"u conditions ( absolute homog5eity ( mat]ial1 save = ! h>d lay] specifi$1 no valley w\ld be develop$1 & !re=e no /ream4 ,if ! surface 0 s *ang$ z to all[ ( ! developm5t ( a valley 7p4 #fc7 ! same pr9ciples w\ld be applicable4 ,z an active /ream passes f a h>d lay] to "o less resi/ant1 ! great] we> on ! latt] gives orig9 to rapids4 ,at fir/ ! rapids w\ld be slight 7a1 ,fig4 #aab71 b w\ld become m consid]able 7b7 z "t & erosion g on4 ,:5 ! b$ ( ! rapids becomes suffici5tly /eep1 ! rapids become falls#di 7cd74 ,:5 ! wat] falls r ?an fl[s ov] ! rock surface bel[ ! h>d lay]1 erosion assumes a new phase4 ,! h>d lay] is !n und]m9$1 & ! und]m9+ causes ! falls to rec$e4 ,?is phase ( erosion is sometimes call$ sapp+4 ,illu/ration3 ,fig4 #aaa4--;,diagram repres5t+ a horizontal lay] ( h>d rock 9 an isl&1 & its effects on erosion4 ,illu/ration3 ,fig4 #aab4--;,diagram illu/rat+ ! developm5t ( a fall :]e ! h>d lay] dips g5tly up-/ream4 ,illu/ration3 ,fig4 #aac4--;,diagram illu/rat+ ! conditions :i* exi/ at ,niag>a ,falls4 7,gilb]t47 ,if ! h>d lay] :i* occasions a fall dips up-/ream 7,fig4 #aab71 its outcrop 9 ! /ream's b$ becomes l[] z ! fall rec$es 7e74 ,:5 x has become s l[ t ! wat] pass+ ov] x no long] reacts effectively aga9/ ! less resi/ant mat]ial b5ea? 7f71 sapp+ ceases1 & ! po9t ( greate/ erosion may be %ift$ f ! s(t mat]ial b5ea? ! fall to ! h>d lay] itself4 ,! actual rate ( erosion at ?is po9t may be no great] ?an be=e1 ?\gh ! relative rate is4 ,"u ^! circum/ances ! v]tical edge ( ! h>d lay] w pres5tly be conv]t$ into an incl9e 7f71 & z ?is takes place ! fall becomes rapids4 ,! conv]sion ( ! falls into ! rapids beg9s ab\t ! "t ! l[] edge ( ! h>d /ratum 9 ! *annel rea*es grade4 ,by cont9uation ( ! process :i* trans=m$ ! falls into rapids1 ! rapids become less rapid1 & :5 ! upp] edge ( ! h>d lay] has be5 br\ght to grade1 ! rapids disappe> 7h1 ,fig4 #aab74 ,! hi/ory ( rapids :i* succe$ falls is ! rev]se ( t :i* prec$$4 ,! lat] rapids are /eepe/ at ! beg9n+ ( _! hi/ory1 ! e>li] at _! end4 ,/at$ 9 o!r t]ms1 rapids are /eepe/ :5 ne>e/ falls 9 "t4 ,slight diff]5ces 9 h>dness 9 successive lay]s (t5 occasion successive falls or rapids 7,fig4 #aad74 ,if ! h>d lay] :i* occasions ! falls be horizontal1 in/ead ( dipp+ up-/ream1 ! g5]al result w\ld be ! same2 b1 o!r ?+s be+ equal1 ! duration ( ! falls develop$ "u ^! conditions w\ld be great]1 s9ce !y mu/ rec$e f>!r be=e becom+ rapids4 ,if ! lay]s ( unequal h>dness 9 a /ream's b$ be v]tical & ! c\rse ( ! /ream at "r angles to ! /rike1 rapids1 & p]haps falls1 w develop 7,fig4 #aae74 ,! *ances = falls are great]1 ! great] ! diff]5ce 9 h>dness4 ,falls develop$ "u ^! conditions1 z well z ! rapids prec$+ & foll[+1 w\ld rema9 con/ant 9 position until ! resi/ant lay] 0 br\ght to grade1 b !y w\ld ultimately disappe> z 9 ! prec$+ cases4 ,falls are n likely to develop :]e ! /rata ( ! /ream's b$ dip d[n-/ream1 ?\gh !y may develop ev5 "u ^! conditions if ! gradi5t ( ! /ream is great] ?an ! dip ( ! /rata 7,fig4 #aaf74 ,illu/ration3 ,fig4 #aad4--;,falls 9 ,utica %ale1 ,canajoh>ie1 ,n4 ,y4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,! inequality ( resi/ance 9 ! rock :i* occasions a fall may be orig9al or second>y4 ,9 ! case ( ,niag>a ,falls#ej 7,fig4 #aac7 relatively resi/ant lime/one ov]lies relatively weak %ale4 ,at ! ,falls ( ,/4 ,an?ony 7,m9neapolis7 lime/one ov]lies friable s&/one4 ,! falls ( ! ,yell[/one & ! ,%o%one ,falls ( ! ,snake ,riv] 7,idaho71 are 9 igne\s rock4 ,9 ! =m] case ! unequal resi/ance is occasion$ by unequal decay ( ! rock1 due p]haps to ! rise ( hot vapors :i* h decompos$ ! rock along ! l9es ( _! asc5t2 9 ! latt]1 a m resi/ant sort ( igne\s rock ov]lies a less resi/ant4 ,/ructural features1 su* z jo9t+1 sometimes give rise to falls1 or det]m9e _! di/9ctive features 7,fig4 #aag71 ev5 :]e ! =mations involv$ are ( uni=m h>dness4 ,a jo9t plane has ! effect ( a weak v]tical or highly incl9$ b$4 ,if an op5 jo9t is discov]$ 9 a /ream's b$1 ! wat] ent]s x4 ,if x f9ds an outlet bel[1 a *annel is worn along ! new l9e ( fl[1 ) rapids or falls :]e ! wat] desc5ds4 ,rock orig9ally homog5e\s may be mu* fractur$ 9 "s p>ts1 :ile x rema9s unbrok5 9 o!rs4 ,:]e a /ream passes f ! solid to ! brok5 portion rapids1 or ev5 falls1 may develop4 ,illu/ration3 ,fig4 #aae4--;,diagram illu/rat+ ! developm5t ( falls ov] a v]tical h>d lay]4 ,illu/ration3 ,fig4 #aaf4--;,diagram illu/rat+ ! possibility ( falls :]e ! b$s dip d[n-/ream4 ,falls may orig9ate 9 /ill o!r ways4 ,if = any reason a /ream is =c$ out ( its valley1 x may 9 its fl[ f9d entrance to ano!r valley1 or to ano!r "p ( its own valley1 ov] a /eep slope4 ,if ! /ructure ( ! slope favors1 a fall may spe$ily develop4 ,! ,falls ( ,/4 ,an?ony are an example1 ! ,mississippi hav+ be5 turn$ out ( its e>li] c\rse by deposits ( glacial drift4 ,aga91 if an ob/ruction ( any sort1 su* z a fl[ ( lava1 dams a /ream1 rapids or falls are develop$ :]e ! wat] ov]fl[s ! dam4 ,:5 a ma9 valley is notably deep5$ by glaciation ! dra9age f tribut>y valleys may fall into x1 if ! tribut>ies 7 n equally deep5$4 ,falls :i* orig9at$ 9 ?is way are common 9 ! we/]n m\nta9s ( ! ,unit$ ,/ates1 z well z 9 mo/ m\nta9 regions rec5tly affect$ by local glaci]s 7,fig4 #aah74 ,"o wat]fall (t5 bre$s o!rs4 ,?us :]e a fall rec$es beyond ! m\? ( a tribut>y /ream1 ! tribut>y falls4 ,! ,falls ( ,m9nehaha1 on a small tribut>y to ! ,mississippi1 ne> ,m9neapolis1 may s]ve z an illu/ration4 ,9 su* cases ! falls may n develop f rapids4 ,once 9 exi/5ce1 ! fall ( a tribut>y foll[s ! same hi/ory z t ( a ma9 /ream4 ,illu/ration3 ,fig4 #aag4--,kepl]'s ,cascade1 9 ! ,yell[/one ,p>k4 ,! jo9t$ & fractur$ "* ( ! igne\s rocks occasions a s]ies ( falls & rapids4 7,idd+s1 ,u4 ,s4 ,geol4 ,surv47 ,/reams :i* h falls are relatively cle>4#ea ,if a /ream favorably situat$ = ! developm5t ( a fall c>ri$ a heavy load1 deposition w\ld take place bel[ ! rapids1 & ! t5d5cy w\ld be to aggrade ! *annel at t po9t & s to prev5t ! developm5t ( ! fall4 ,falls occur only on /reams :i* h relatively high gradi5ts4 ,?is means t ! /reams :i* h falls are well above base-level1 & /reams well above base-level are "y4 ,falls !re=e are a m>k ( topographic y\?4 ,illu/ration3 ,fig4 #aah4--,! ,upp] ,yosemite ,falls4 ,! fall ( ! ,niag>a#eb 7,pl4 ,,ix7 is "o ( ! mo/ rem>kable kn[n1 bo? because ( its l>ge volume ( wat] & its great desc5t1 betwe5 #afj & #agj feet4 ,! rate at :i* ! fall is rec$+ is a matt] ( int]e/ n only 9 itself1 b because1 once det]m9$1 x may be made to s]ve z a unit ( measurem5t = c]ta9 important ev5ts 9 geological hi/ory4 ,x 0 =m]ly conjectur$ t ?is fall 0 rec$+ at ! rate ( "o to ?ree feet p] c5tury1 b x 0 n until rec5t ye>s t its actual rate ( recession 0 approximately fix$4 ,by surveys execut$ 9 #ahdb & #ahij x has be5 det]m9$ t its av]age rate ( recession betwe5 ^? dates 0 some?+ l #d feet p] ye>1 or ab\t #aej times z great z ! highe/ e/imate /at$ above4 ,x is to be not$ t ?is is ! av]age rate ( recession1 = all p>ts ( ! l$ge ov] :i* ! wat] falls are n rec$+ at ! same rate4 ,! po9t ( ! 8,horse%oe0 has1 dur+ ! same "t1 gone back at m ?an twice ?is rate4#ec ,illu/ration3 ,fig4 #aai4--;,a gr\p ( pot-holes4 7,turn]1 ,u4 ,s4 ,geol4 ,surv47 ,rapids & falls sometimes occasion ! developm5t ( pot-holes 7,fig4 #aai71 a peculi> r ?an important erosion feature4 ,! holes are excavat$ 9 "p by ! fall+ & eddy+ ( silt-*>g$ wat]1 b *iefly by /ones :i* ! eddies move4 ,pot-holes :i* are n n[ 9 imm$iate association ) rapids or falls (t5 po9t to ! =m] exi/5ce ( rapids or falls4 ,rock t]races4--,! t5d5cy to sapp+ %[n 9 _m wat]falls is also %[n 9 ! wea!r+ & erosion ( ! sides ( a valley :]e a h>d lay] outcrops above ! bottom1 & ! pr(ile ( ! side slopes ( ! valley simulates t ( ! /ream2 t is1 ! slope becomes g5tle j above ! h>d lay]1 & /eep1 or ev5 v]tical1 at & bel[ its outcrop4 ,?is is illu/rat$ by ,fig4 #abj1 :]e ! h>d lay] ?r\gh :i* ! /ream has sunk its valley /&s out z a rock t]race on ei!r side ( ! valley4 ,su* t]races are n r>e & are popul>ly believ$ to be old 8wat]-l9es02 t is1 to repres5t ! height at :i* ! wat] once /ood4 ,9 "o s5se ?is int]pretation is correct1 s9ce a riv] has /ood at all levels betwe5 t ( ! surface 9 :i* its valley />t$1 & its pres5t *annel1 b ! %elf ( h>d rock does n mean t ! riv]1 aft] atta9+ its pres5t *annel1 0 ev] s l>ge z to fill ! valley to ! level ( ! t]race4 ,rock t]races may also result f *anges ( level4 ,illu/ration3 ,fig4 #abj4--;,diagram to illu/rate ! developm5t ( rock t]races4 ,n>r[s4--,inequalities 9 h>dness occasion ano!r peculi>ity common to valleys4 ,if a /ream crosses v]tical or highly incl9$ /rata ( unequal h>dness1 its valley is usually con/rict$ at ! cross+ ( ! h>d] lay]s4 ,if su* a con/riction be notable x is call$ a n>r[s1 or sometimes a wat]-gap 7,figs4 #aba1 #aei1 & ,fig4 #b1 ,pl4 ,,xii74 ,! ,appala*ian ,m\nta9s af=d num]\s examples4 ,! con/riction arises because ! processes :i* wid5 ! valley are less effective on ! h>d lay] ?an on ! less resi/ant ones on ei!r h&4 ,?\gh mo/ n>r[s are due to ! sup]ior resi/ance ( ! rock :]e !y occur1 !y are sometimes ! result ( o!r causes4 ,illu/ration3 ,fig4 #aba4--,l[] n>r[s ( ! ,b>aboo ,riv]1 ,wis4 ,! ev5-cre/$ ridge is ,huronian qu>tzite4 ,! surr\nd+s are ( ,cambrian s&/one4 7,atwood47 ,illu/ration3 ,fig4 #abb4--;,a hog-back1 ,jura-,trias4 ,colorado ,city1 ,colo4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,n>r[s are mu* m conspicu\s 9 c]ta9 /ages ( erosion ?an 9 o!rs4 ,:ile a valley is /ill s "y z to be n>r[ at all po9ts1 no n>r[s w be conspicu\s2 b at a lat] /age 9 its hi/ory1 :5 ! valley is o!rwise wide1 n>r[s are m pron\nc$4 ,at a /ill lat] /age1 :5 ! h>d /rata !mselves approa* base-level1 ! n>r[s aga9 become inconspicu\s4 ,f :at has prec$$ x is cle> t rapids or falls are likely to occur at n>r[s1 especially 9 ! e>ly "p ( _! hi/ory4 ,o!r effects on topography4--,inequalities 9 ! h>dness ( rock develop c]ta9 peculi>ities ( topography o!r ?an ^? ( valleys4 ,! less resi/ant portions ( a l& area m or less di/ant f /reams are worn d[n m readily ?an ^? :i* are m resi/ant4 ,if great areas ( high l& be capp$ ) h>d rock !y are likely to rema9 z plateaus aft] surr\nd+ areas ( less resi/ance are br\ght l[4 ,if ! h>d capp+ affects a small area in/ead ( a l>ge "o1 ! elevation is a butte1 a hill1 or a m\nta91 in/ead ( a plateau 7,fig4 #aaj74 ,_m buttes & small mesas are b remnants ( =m] plateaus 7,mesa ,lauriano1 ,n4 ,m41 ,fig4 #a1 ,pl4 ,,xii74 ,a feature ( buttes & mesas capp$ by h>d rock is ! /eep slope or cliff correspond+ to ! edge ( ! h>d b$ 7,figs4 #gh & #aji74 ,illu/ration3 ,fig4 #abc4--;,a ridge due to ! outcropp+ edge ( h>d ,jurassic rock4 ,wyom+4 ,if ! rock ( a region be /ratifi$ & ! lay]s tilt$1 ! removal ( ! s(t] b$s leaves ! h>d] ones project+ above ! g5]al level 9 ! =m ( ridges or 8hog-backs0 7,figs4 #abb & #abc74 ,dikes ( igne\s rock1 h>d] ?an ! b$s :i* !y int]sect1 likewise become ridges aft] ! degradation ( _! surr\nd+s4 ,! plugs ( old volcanic v5ts & o!r igne\s intrusions ( limit$ area (t5 con/itute conspicu\s hills or m\nta9s aft] erosion has remov$ _! less resi/ant surr\nd+s 7,fig4 #abd74 ,inequalities ( h>dness are !re=e responsible = _m hills & ridges4 ,9 ! isolation ( ! hills & ridges picturesque coves are develop$1 :]e ! attitude & di/ribution ( ! weak & /rong rocks are propiti\s4 ,! bottoms ( ! coves are locat$ on ! weak rocks1 & above !m rise ! precipit\s slopes ( ! resi/ant ones4 ,r\nd valley 7,fig4 #a1 ,pl4 ,,xvii1 ,high ,bridge1 ,n4 ,j41 quadrangle1 ,u4 ,s4 ,geol4 ,surv47 & ! coves ab\t ! head ( ,hiawassee ,riv] 7,dahlonega1 ,ga41 quadrangle7 are examples4 ,illu/ration3 ,fig4 #abd4--,matteo tepee1 ,wyo4 ,mass ( igne\s rock expos$ by erosion1 & pres]v$ because ( its sup]ior resi/ance4 7,detroit ,photo4 ,co47 ,ridges & hills result+ f ! unequal degradation ( unequally resi/ant t]ranes are n equally prom95t at all /ages 9 an erosion cycle4 ,9 e>ly y\? ! mat]ial surr\nd+ ! h>d bodies ( rock has n be5 remov$2 9 e>ly maturity consid]able portions ( _! surr\nd+s /ill rema9 ab\t !m2 b 9 late maturity or e>ly old age ! outcropp+ masses ( h>d rock h be5 m p]fectly isolat$ & are mo/ conspicu\s4 ,mo/ ( ! ev5-cre/$ ridges ( ! ,appala*ian sy/em1 z well z _m o!rs :i* might be m5tion$1 became ridges 9 ?is way4 ,9 ! f9al /ages ( an erosion cycle ! ridges ( h>d rock are !mselves br\ght l[4 ,isolat$ remnants ( h>d rock :i* rema9 di/9ctly above _! surr\nd+s 9 ! late /ages ( an erosion cycle 7,fig4 #abd7 are kn[n z ,monadnocks1 ! "n be+ d]iv$ f ,m\nt ,monadnock1 ,n4 ,h41 an elevation ( ?is sort develop$ 9 a cycle ant$at+ ! pres5t4 ,illu/ration3 ,figs4 #abe-bg4--;,diagrams illu/rat+ piracy1 :]e ! /ream :i* does n fl[ ov] rock ( sup]ior h>dness captures ^? :i* d4 ,fig4 #abf repres5ts a fur!r developm5t ( ! dra9age %[n 9 ,fig4 #abe1 & ,fig4 #abg repres5ts a /ill lat] /age4 ,illu/ration3 ,figs4 #abh-cj4--;,diagrams to illu/rate piracy1 :]e ! compet+ /reams all cross a h>d lay]4 ,! diagrams repres5t successive /ages ( developm5t4 ,adju/m5t ( /reams to rock /ructures4--,valleys 7gullies7 locate !mselves at ! outset )\t imm$iate reg>d to ! h>dness & s(tness ( _! b$s4 ,x is prim>ily ! slope ab\t ! head ( a gully :i* det]m9es its l9e ( gr[?1 ?\gh relative h>dness (t5 det]m9es ! details ( slope1 ev5 9 ! e>ly /ages ( an erosion cycle4 ,once e/abli%$1 /reams t5d to hold _! c\rses1 ev5 if ?is involves ! cross+ ( resi/ant lay]s4 ,:ile a region :]e m & less resi/ant lay]s ( rock come to ! surface is 9 a y\?ful /age ( erosion1 "s ( ! valleys 7& !re=e ! /reams7 are likely to be locat$ on ! less resi/ant rock1 "s on ! m resi/ant1 & "s p>tly on ! "o & p>tly on ! o!r4 ,! /reams on ! weak] rock w deep5 _! valleys m rapidly ?an ! o!rs1 & ^? :i* fl[ across /rong] & weak] rocks alt]nately w deep5 _! valleys m rapidly ?an ^? :i* run on h>d rock all ! "t4 ,! =m] conclusion is self-evid5t4 ,! latt] appe>s f ! fact t rapids w be likely to develop at ! cross+ ( ea* h>d lay]1 ?us accel]at+ erosion at ^? po9ts4 ,su* a /ream !re=e n only has less h>d rock to erode ?an "o :i* fl[s on resi/ant rock all ! "t1 b x erodes t :i* x does cross mu* fa/]4 ,illu/ration3 ,figs4 #aca1 #acb4--,! capture ( ! head ( ,beav]dam ,creek by ! ,%5&oah ,va4-,w4 ,va4 7,aft] ,willis47 ,/reams :i* d n cross h>d lay]s !re=e h an advantage ov] ^? :i* d1 & ! tribut>ies to su* /reams1 s9ce !y jo9 deep] ma9s1 h an advantage ov] ! tribut>ies to ! o!rs4 ,! valleys ( ! =m] may l5g!n until _! heads rea* ! latt]1 & capture _! /reams4 ,?is sequ5ce ( ev5ts is illu/rat$ 9 ! accompany+ diagrams 7,figs4 #abe-bg74 ,ev5 :]e sev]al /reams cross ! same resi/ant b$1 piracy is likely to take place among !m1 = "s are sure to deep5 _! valleys fa/] ?an o!rs1 because ( inequalities ( volume1 load1 or h>dness4 ,?is is illu/rat$ by ,figs4 #abh-cj4 ,an actual case is %[n 9 ,figs4 #aca1 #acb4 ,?\gh piracy may take place :5 /reams d n fl[ ov] rock ( unequal h>dness 7p4 #ajc71 x is mu* m common :]e unequal resi/ance ( ! rock puts "o /ream at a disadvantage z comp>$ ) ano!r4 ,! *anges 9 ! c\rses ( /reams1 by means ( :i* !y come to su/a9 def9ite & /able relations to ! rock /ructure b5ea?1 are kn[n z processes ( adju/m5t4#ed ,s9ce /reams & valleys adju/ !mselves to o!r conditions z well1 ?is phase ( adju/m5t may be call$ /ructural adju/m5t4 ,/ructural adju/m5t is n uncommon among riv]s fl[+ ov] /rata :i* are v]tical or highly incl9$1 s9ce 9 ^! positions ! h>d & s(t /rata are mo/ likely to come to ! surface 9 frequ5t alt]nation4 ,! small] /reams suff] capture & adju/m5t fir/1 s9ce1 z a rule1 !y h %all[] valleys4 ,x (t5 happ5s t ma9 /reams1 because ( _! deep] valleys1 hold c\rses n 9 adju/m5t ) /ructure 7! ,delaw>e1 ! ,susquehanna1 etc471 :ile tribut>y /reams are captur$1 div]t$1 & adju/$4 ,! capture ( a tribut>y1 h[ev]1 leads bo? to ! dim9ution ( its ma9 & to ! increase ( its captor1 & ! weak5$ /ream may ultimately fall a prey to ! "o :i* is /r5g!n$4 ,! processes ( adju/m5t g on until ! /reams fl[ z mu* z possible on ! weak] b$s1 & z little z possible on ! /rong]1 :5 adju/m5t is complete4 ,?is am\nts to ! same ?+ z say+ t ! outcrops ( ! h>d lay]s t5d to become divides4 ,9 _m cases an area is s situat$ t !re is no escape = its dra9age except across resi/ant rock4 ,9 ?is case its dra9age is completely adju/$ :5 z few /reams z possible cross ! resi/ant rock1 & ^! by ! %orte/ r\tes4 ,adju/m5t has be5 c>ri$ to a high degree ( p]fection 9 mo/ p>ts ( ! ,appala*ian sy/em4 ,"h1 z 9 all o!r m\nta9s ( simil> /ructure1 /rata ( unequal h>dness 7 fold$ into ridges4 ,9 ?is case1 ! folds h be5 truncat$ by erosion1 expos+ ! m & ! less resi/ant b$s 7,h & ,s respectively7 9 alt]nate belts along ! flanks ( ! truncat$ folds 7ab & cd1 ,fig4 #acc74 ,! /reams1 especially ! less] ones1 n[ fl[ along ! /rike ( ! s(t] b$s mu* m commonly ?an else:]e1 & :]e !y cross ! h>d lay]s x is usually at "r angles to ! /rike4 ,?is is %[n 9 ,fig4 #acd1 :]e ! arr[s indicate ! direction ( /rike4 ,9 ! hi/ory ( ^! riv]s1 h[ev]1 a factor is involv$ :i* has n yet be5 consid]$1 & ^! /reams w be ref]r$ to lat]4 ,illu/ration3 ,fig4 #acc4--;,diagram %[+ ! outcrops ( h>d lay]s on ! flanks ( a truncat$ fold4 cd repres5ts ! pres5t surface2 dott$ l9es above1 e>li] surfaces4 ,illu/ration3 ,fig4 #acd4--;,example ( adju/$ dra9age 9 a region ( fold$ rocks1 ,va4-,w4 ,va4 ,illu/ration3 ,fig4 #ace4--;,diagram to illu/rate readju/m5t ( dra9age1 z base-level is approa*$4 ,illu/ration3 ,fig4 #acf4--;,diagram to illu/rate sup]imposition4 ,! consequ5t /ream on ! upp] =mation is sup]impos$ on ! und]ly+ /ructures :5 ! upp] b$ has be5 cut ?r\gh4 ,z base-level is approa*$1 ! outcrops ( h>d rock are br\ght l[4 ,:5 !y h be5 r$uc$ to ! level ( _! surr\nd+s1 ! /reams may fl[ )\t reg>d to ! resi/ance ( ! rock b5ea?1 = d[nw>d cutt+ has ceas$4 ,z ?is /age ( erosion is approa*$1 a readju/m5t ( ! dra9age may take place1 & ! wat]s :i* _h tak5 long & circuit\s c\rses to avoid h>d rock1 may *ange _! c\rses to m direct ones 7comp>e ,figs4 #acj & #ace74 ,adju/m5t is1 !re=e1 a relative t]m1 & /reams :i* are adju/$ at "o /age ( erosion1 are n necess>ily adju/$ at ano!r4 ,x sometimes happ5s t rocks ( unequal resi/ance are cov]$ by b$s ( uni=m h>dness4 ,a consequ5t /ream develop$ on ! latt] may f9d itself out ( /ructural adju/m5t :5 x has cut its *annel d[n to ! level ( ! het]og5e\s b$s bel[4 ,su* a /ream is said to be sup]impos$ 7,fig4 #acf7 on ! und]ly+ /ructure4 ,/ructural adju/m5t is likely to foll[4 ,,influ5ce ,,( ,,jo9ts ,,& ,,folds4 ,jo9ts4--,v>i\s /ructural features ( rock o!r ?an h>dness influ5ce its erosion4 ,ap>t f ! /ratification planes1 mo/ rock =mations are affect$ by jo9ts or fissures4 ,! jo9ts are (t51 b n always1 ne>ly v]tical4 ,two sets are g5]ally pres5t1 & sometimes m4 ,if b two1 !y usually meet at a l>ge angle2 if m ?an two1 two are likely to be ne>ly p]p5dicul> to ea* o!r1 :ile ! ?ird & f\r? sets h su* directions z to cut ! o!rs at l>ge angles4 ,^! jo9ts all[ ! +ress ( wat]1 roots1 etc41 :i* help to wea!r & disrupt rocks4 ,occasionally !re is notable sag ( ! b$s ( rock along jo9t planes1 b ?is effect is usually sup]ficial only 7,fig4 #acg74 ,:]e ! jo9tage planes are frequ5t & op51 ! columns b\nd$ by !m sometimes topple ov] on cliff faces1 ei!r by und]cutt+1 or by ! w$ge-"w ( roots or ice4 ,! effect ( jo9ts on erosion may (t5 be se5 along a /ream :i* fl[s 9 a rock gorge4 ,9 su* situations1 ! outl9es ( ! banks are sometimes angul>1 & sometimes cr5ate 7,fig4 #ach71 ! rentrants be+ locat$ at ! jo9ts4 ,by work+ into & wid5+ jo9ts1 runn+ wat] sometimes isolates masses ( rock z isl&s 7,fig4 #aci74 ,9 a region free f mantle rock1 or :]e ! mantle rock is meagre1 jo9ts (t5 det]m9e ! c\rses ( valleys by direct+ ! c\rse ( surface dra9age4 ,?is is %[n 9 _m p>ts ( ! arid we/4 ,9 regions :]e ! rocks are notably fault$1 ! c\rses ( ! /reams are sometimes controll$ by ! c\rses ( ! fault planes4 ,?is is ! case1 = example1 9 c5tral ,wa%+ton4#ee ,illu/ration3 ,fig4 #acg4--,%[s ! sagg+ ( b$s along jo9ts4 ,! di/urbance does n ext5d f> bel[ ! surface4 ,cook's qu>ry 7,niag>a lime/one7 ne> ,la ,salle1 ,niag>a ,co41 ,n4 ,y4 7,gilb]t1 ,u4 ,s4 ,geol4 ,surv47 ,! jo9t+ ( rocks (t5 %[s itself di/9ctly 9 ! wea!r$ faces ( cliffs 7,figs4 #adj & #ada71 especially 9 arid & semi-arid regions1 or :]e ! slope is too /eep = ! accumulation ( soil & rock-wa/e on its surface4 ,if a /ream fl[+ ov] jo9t$ rock has falls1 ! conditions are sometimes af=d$ = ! developm5t ( an exceptional & /rik+ sc5ic feature4 ,if above ,niag>a ,falls1 = example1 !re 7 an op5 jo9t 9 ! b$ ( ! /ream 7z at b1 ,fig4 #adb71 "s portion ( ! wat] w\ld desc5d ?r\gh x4 ,aft] rea*+ a l[] level x might f9d or make a passage ?r\gh ! rock to ! riv] bel[ ! falls4 ,if ev5 a little wat] took su* a c\rse1 ! fl[ w\ld enl>ge its *annel1 mak+ a passageway betwe5 ! jo9t ?r\gh :i* ! wat] desc5d$ & ! valley bel[ ! falls 7bcde1 ,fig4 #adb74 ,?is passageway might become l>ge en\gh to accommodate all ! wat] ( ! riv]4 ,9 ?is case1 ! entire fall w\ld be transf]r$ f ! position :i* x previ\sly occupi$ 7f7 to ! position ( ! enl>g$ jo9t 7b74 ,! fall w\ld !n rec$e4 ,! und]gr\nd *annel betwe5 ! old falls & ! new w\ld be bridg$ by rock 7bf & f1 ,fig4 #adc71 mak+ a natural bridge4 ,! natural bridge ne> ,lex+ton1 ,va4 7,fig4 #add71 almo/ #bjj feet above ! /ream :i* fl[s b5ea? x1 is believ$ to h be5 develop$ 9 ?is way4 ,a simil> bridge is n[ 9 process ( developm5t 9 ,two ,m$ic9e ,riv] 9 nor?we/]n ,montana 7,fig4 #ade74 ,once 9 exi/5ce1 a natural bridge w sl[ly wea!r away4 ,illu/ration3 ,fig4 #ach4--;,figure %[+ cr5ate riv] bank1 ! rentrants be+ det]m9$ by jo9ts4 ,dells ( ! ,wiscons9 ,riv]1 ne> ,kilb\rn1 ,wis4 7,atwood47 ,illu/ration3 ,fig4 #aci4--,lone ,rock4 ,an isl& isolat$ by ! notable wid5+ ( a s]ies ( jo9ts4 ,! jo9ts 9 ! rock ( ! isl& h !mselves be5 s wid5$ t a r[boat may be tak5 ?r\gh x 9 two directions4 ,l[] ,dells ( ! ,wiscons94 7,mey]s47 ,illu/ration3 ,fig4 #adj4--;,effect ( column> /ructure on wea!r+4 ,mat]ial unconsolidat$4 ,spur ( s\? end ( ,%eep ,m\nta94 7,lipp9cott1 ,u4 ,s4 ,geol4 ,surv47 ,x is n to be und]/ood t all natural bridges h _h ?is hi/ory4 ,!y are sometimes develop$ f und]gr\nd caves :5 p>ts ( _! ro(s are de/roy$1 z well z 9 v>i\s o!r ways4 ,illu/ration3 ,fig4 #ada4--;,effect ( column> /ructure on wea!r+4 ,big ,bad ,l&s1 ,s4 ,d4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,folds4--,! erosion ( fold$ /rata 7anticl9es & syncl9es7 leads to ! developm5t ( di/9ctive topographic features4 ,s soon z a fold beg9s to be lift$1 x is1 by reason ( its position1 subject to m rapid erosion ?an its surr\nd+s4 ,= ! same reason ! cre/ ( ! fold is likely to be degrad$ m rapidly ?an its l[] slopes1 & mu/ suff] m degradation be=e x is br\ght to base-level4 ,folds are usually compos$ ( b$s ( unequal resi/ance1 & z ! degradation ( a fold proce$s1 successive lay]s are worn f ! top1 & ! alt]nat+ h>d & s(t lay]s compos+ x are expos$4 ,s soon z ?is is accompli%$1 adju/m5t ( ! /reams is likely to beg91 & ! wat]c\rses1 & lat] ! valley pla9s1 come to be locat$ on ! outcrops ( ! less resi/ant lay]s1 :ile ! outcrops ( ! h>d] b$s become ridges4 ,if ! axis ( an erod$ anticl9e 7 horizontal1 a giv5 h>d lay]1 ! ar* ( :i* has be5 cut (f1 w\ld1 aft] erosion1 outcrop on bo? sides ( ! axis4 ,:5 ! topography 0 mature ^! outcrops w\ld con/itute p>allel ridges1 or p>allel l9es ( hills2 :5 ! region _h be5 base-level$1 ! outcrops w\ld be 9 p>allel belts1 ?\gh no long] ridges or hills4 ,! l[] ! plane ( truncation1 ! f>!r ap>t w\ld ! outcrops be 9 ! anticl9e1 & ! ne>] toge!r 9 ! syncl9e 7comp>e ab & cd1 ,fig4 #acc74 ,illu/ration3 ,fig4 #adb4--;,a natural bridge 9 process ( developm5t2 longitud9al section at ! left2 transv]se section1 look+ t[>d e1 at ! "r4 ,if1 on ! o!r h&1 ! axis ( ! anticl9e or syncl9e to be erod$ 0 n horizontal1 t is1 if x plung$1 ! topographic result w\ld be some:at diff]5t4 ,suppose a plung+ anticl9e to be truncat$ at base-level4 ,if ei!r end ( ! fold plung$ bel[ ! plane ( truncation1 ! outcrops ( a giv5 lay] on opposite sides ( ! axis w\ld conv]ge 9 ! direction ( plunge1 & come toge!r at ! end4 ,at a /age ( erosion ant$at+ planation 7say late maturity7 !re w\ld h be5 a ridge1 or a succession ( hills1 9 ! position correspond+ to ! outcrop ( a h>d lay]1 ) a canoe-%ap$ valley )94 ,if two h>d lay]s 7 involv$1 in/ead ( "o1 !re w\ld be two encircl+ ridges1 ) a curv$ valley betwe5 !m1 & a canoe-%ap$ valley )9 ! inn]mo/ 7,fig4 #adf74 ,if ! anticl9e plung$ bo? ways1 ! valley enclos$ by ! h>d-lay] ridge w\ld be canoe-%ap$ at bo? ends 7,fig4 #adg74 ,9 su* a case !re w\ld be likely to be a l[ gap 7wat]-gap7 9 ! rim ( ! valley ?r\gh :i* ! dra9age :i* degrad$ ! surface escap$1 b !re w\ld be likely to be b "o1 = if two or m /reams _h dra9$ ! area ( ! valley at an e>ly /age ( erosion1 "o w\ld be likely to h captur$ ! o!rs 7see p4 #ach7 be=e late maturity4 ,a succession ( d\bly-plung+ anticl9es & syncl9es might give rise to a v complex s]ies ( ridges & valleys4 ,illu/rations ( ! above ph5om5a are f\nd at v>i\s po9ts 9 ! ,appala*ian ,m\nta9s1 especially 9 ea/]n ,p5nsylvania4#ef ,illu/ration3 ,fig4 #adc4--,! same z ,fig4 #adb at a lat] /age ( developm5t4 ,illu/ration3 ,fig4 #add4--,! ,natural ,bridge ( ,virg9ia1 f ! s\!a/ 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #ade4--;,a natural bridge 9 developm5t4 ,two ,m$ic9e ,riv]1 ,mont4 ,corresponds to ! /age repres5t$ by ,fig4 #adb1 & ! view corresponds to t %[n diagrammatically at ! "r-h& end ( ! figure4 7,:itney47 ,9 ! /ructural adju/m5t :i* goes ) ! erosion ( folds1 x (t5 happ5s t ! valleys come to be locat$ on ! anticl9es1 :ile ! outcrops ( ! h>d lay]s on ! flanks ( ! anticl9es1 or ev5 9 ! orig9al syncl9es1 become ! m\nta9s4 ,! adju/m5ts by :i* valleys come to be locat$ on anticl9es are some:at z foll[s3#eg ,fig4 #adh repres5ts two d\bly-plung+ anticl9es ) a syncl9e betwe51 ! relative elevations be+ %[n by cont\r l9es4 ,at ! outset1 ! dra9age ( su* a region mu/ h foll[$ ! /ructural valley1 & its initial c\rse1 consequ5t on ! slope1 mu/ h be5 d[n ! axial tr\gh4 ,dra9age f ! anticl9es into ! syncl9es w\ld h promptly develop$ valleys1 & ! valleys w\ld soon h acquir$ /reams4 ,illu/ration3 ,fig4 #adf4--;,a canoe-%ap$ valley bord]$ by a ridge =m$ by ! outcrop ( a h>d lay] 9 a plung+ syncl9e4 ,! ridge b\nd+ ! canoe-valley is sep>at$ f an out] ridge by a curv$ valley und]la9 by relatively weak rock4 7,aft] ,willis47 ,illu/ration3 ,fig4 #adg4--;,a diagram to illu/rate ! effects ( erosion on a d\bly-plung+ anticl9e made up ( b$s ( unequal h>dness4 ,illu/ration3 ,figs4 #adh-ea4--;,diagrams to illu/rate ! %ift+ ( riv]s f a syncl9al to an anticl9al position4 7,aft] ,davis47 ,! anticl9es & syncl9es "u consid]ation are assum$ to h a ?ick h>d lay] at ! surface1 & s(t] b$s bel[4 ,?is is %[n 9 ! cross-section introduc$ 9 ! figure1 ! upp] h>d /ratum 7m7 be+ indicat$ by ! dots1 :ile ! s(t] "o 7n7 is :ite4 ,! l9e oo repres5ts base-level1 :i* is bel[ ! h>d lay] bo? 9 ! syncl9e & anticl9e1 b mu* f>!r bel[ 9 ! latt] position ?an 9 ! =m]4 ,because ( _! high] gradi5ts1 & because ( ! great] fractur+ to :i* ! region !y dra9 0 presumably subject at ! "t ( fold+1 ! tribut>y /reams might cut ?r\gh ! h>d lay] soon] ?an ! ma9 /ream :i* !y jo94 ,?is done1 !y w\ld enl>ge _! valleys rapidly 9 ! s(t] rock b5ea?1 & second>y tribut>ies w\ld be develop$ 7,fig4 #adi74 ,:5 ! condition ( ?+s repres5t$ 9 ,fig4 #adi is rea*$1 ! /reams c & d1 tribut>y to ! syncl9al /ream1 come into competition4 ,! =m] has ! advantage ov] ! latt]1 because x jo9s ! ma9 /ream at a l[] level4 ,/ream c w !re=e be likely to capture d4 ,! incipi5t /ages ( ! capture are /eal?y1 & ! lat] bold4 ,at fir/ ! divide betwe5 _! head wat]s is %ift$ nor?w>d in* by in*1 because ! gradi5t t[>d g is high] ?an t t[>d e4 ,! capture ( ! head wat]s ( e is z sl[ z ! migration ( ! divide1 until ! divide rea*es ! po9t :]e e jo9s f4 ,! /ream f is !n div]t$ promptly into ! valley ( g1 & is at once l$ away to c 7see ,fig4 #aej74 ,/r5g!n$ by its increas$ volume1 ! /ream c 7,fig4 #aej7 l[]s its valley across ! h>d lay] m rapidly ?an be=e1 & s holds ! advantage x has ga9$4 ,n only ?is1 b ! behead$ /ream d 7,fig4 #aej71 because ( its dim9i%$ volume1 s9ks its valley into ! h>d lay] less rapidly ?an be=e1 & its decrease 9 p[] also works to ! advantage ( ! /ream lead+ to c4 ,! result is t ! divide betwe5 fg & d does n rema9 con/ant1 b is driv5 back /ep by /ep t[>d a4 ,simil>ly a tribut>y to ! ma9 /ream at b 7,fig4 #aej71 may by means ( its tribut>y h1 capture ! wat]s ( fg1 & lead !m to ! syncl9al valley at b 7comp>e ,figs4 #aej & #aea74 ,depriv$ ( its ma9 s\rce ( supply 7at c7 ! syncl9al /ream is greatly dim9i%$ above b1 & cuts m & m sl[ly1 :ile ! /ream fgh 7,fig4 #aea71 hav+ great] volume & work+ ma9ly 9 s(t] rock1 s9ks its *annel fa/] ?an ! /ream 9 ! syncl9al axis4 ,"u ^! circum/ances1 ! /ream at f may cut its valley bel[ ! valley 9 ! syncl9al axis a 7,fig4 #aej74 ,9 ?is ev5t1 ! divide betwe5 f & a 7,fig4 #aej7 may be pu%$ back until ! syncl9al /ream is behead$ at a & c>ri$ out ( ! syncl9e & ov] into ! anticl9al valley 7,fig4 #aea74 ,?us1 ! old anticl9al axis comes to be ! c\rse ( ! ma9 /ream4 ,simil>ly ! /ream ent]+ ! syncl9e at b 7,fig4 #aea7 might lat] be captur$ by i1 ?us l5g!n+ its anticl9al c\rse4 ,x is n to be und]/ood t ?is sequ5ce ( ev5ts w take place 9 ! degradation ( e anticl9e1 b ! pr9ciples "h set =? w always be op]ative4 ,! result specifi$ w be accompli%$ :]ev] h>d & s(t lay]s h ! relations indicat$ 9 ! diagrams2 t is1 :]e ! /ream 9 ! syncl9e f9ds itself on a resi/ant lay] z x approa*es base-level1 :ile at ! same "t ! 7orig9al7 tribut>y /reams are work+ 9 s(t] b$s4 ,x is n to be und]/ood1 !re=e1 t /reams migrate f syncl9es to anticl9es = ! sake ( gett+ out ( ! =m] positions into ! latt]4 ,if !y %ift _! c\rses x is to f9d easi] ones4 ,t ^! *anges are n fanciful is %[n by ! fact t ! adju/m5t describ$ corresponds ) t %[n 9 _m p>ts ( ! ,appala*ian ,m\nta9s1 & 9 o!r m\nta9s ( simil> /ructure4 ,if 9 a lat] /age ( its hi/ory1 ! new ma9 /ream1 fh1 7 to cut its b$ d[n to a l[] h>d lay]1 :ile ! orig9al /ream1 ab1 rea*$ a s(t] b$ b5ea? ! h>d "o above1 ! latt] w\ld aga9 h an advantage1 & a new s]ies ( adju/m5ts w\ld be inaugurat$ :i* might result 9 re-e/abli%+ ! ma9 /ream 9 its orig9al syncl9al position4 ,,effect ,,( ,,*anges ,,( ,,level4 ,rise4--,if aft] be+ base-level$1 or notably r$uc$ by erosion1 a region is uplift$ s z to increase ! gradi5ts & !re=e ! velocities ( ! /reams :i* dra9 x1 ! /reams are said to be rejuv5at$1 & a new cycle ( erosion is begun4 ,if ! rise ( ! area 7 equal ev]y:]e1 :ile ! coa/ l9e rema9$ con/ant 9 position1 !re w\ld be an imm$iate increase 9 velocity only at ! deb\*ures ( ! /reams fl[+ directly into ! sea4 ,at ! deb\*ures ( su* /reams !re w\ld be rapids or falls4 ,ea* rapids or falls w\ld promptly rec$e1 & ) ! recession1 ! accel]ation ( velocity result+ f ! uplift w\ld be felt f>!r & f>!r up-/ream1 & ultimately to its s\rce4 ,! rejuv5at$ /reams w\ld cut new valleys 9 ! bottoms ( _! old ones 7,figs4 #aeb & #aec74 ,! new valleys w\ld beg9 :]e ! increase 9 velocity 0 fir/ felt1 & !y w\ld be l5g!n$ by head erosion j z valleys ( ! fir/ cycle 7 l5g!n$4 ,illu/ration3 ,fig4 #aeb4--;,cross-section ( a wide valley1 ab1 9 ! bottom ( :i* a y\ng] valley1 cd1 has be5 excavat$ z ! result ( uplift4 ,illu/ration3 ,fig4 #aec4--;,diagram to illu/rate 9 gr\nd plan an ideal case ( rejuv5ation z ! result ( uplift4 ,:5 ! head ( ! new "p ( a valley ( a rejuv5at$ /ream rec$es pa/ ! m\? ( a tribut>y adju/$#eh to ! gradi5t ( ! ma9 /ream be=e rejuv5ation1 ! velocity ( ! tribut>y is accel]at$ at its deb\*ure1 & x beg9s to excavate a new valley 9 ! bottom ( its old "o4 ,! new valley comm5ces at ! l[] end ( ! old "o1 & develops headw>d 7a & b1 ,fig4 #aec74 ,good illu/rations are furni%$ by ! /reams 9 ! we/ c5tral "p ( ,new ,j]sey4 ,! ,delaw>e has "h a %>ply def9$ valley1 & its tribut>ies are ess5tially z deep z _! ma9 at ! po9t ( junction4 ,above ?is po9t !y h high gradi5ts = a %ort di/ance 7?ree to six miles71 beyond :i* !y w9d sluggi%ly 9 wide valleys ) l[ gradi5ts across a relatively high plateau4 ,_! pr(iles are illu/rat$ by ,fig4 #aed4 ,! flat1 ?\gh high1 surface 9 :i* _! upp] c\rses lie1 appe>s to h be5 ne>ly base-level$ 9 an e>li] cycle1 & !n to h be5 elevat$4 ,! date ( ! elevation is fix$1 9 t]ms ( erosion1 by ! "t necess>y = ! excavation ( ! ,delaw>e gorge1 & ! n>r[ gorges along ! l[] c\rses ( its tribut>ies4 ,x 0 s rec5t t ! effects ( rejuv5ation1 proce$+ f ! deb\*ures ( ! tribut>ies t[>d _! heads1 h n yet advanc$ f> f ! ,delaw>e4 ,simil> relations are f\nd else:]e 7,fig4 #a1 ,pl4 ,,xiii1 s4 c4 ,col474 ,ano!r peculi>ity ( rejuv5at$ dra9age is %[n 9 ,fig4 #b1 ,plate ,,xiii 7s4 ,kan474 ,"h ,elm ,creek fl[s at a level #bjj feet bel[ t ( ,s& ,creek1 #d miles di/ant4 ,! valley ( ! =m] appe>s to h ent]$ ^u a new cycle z ! result ( uplift1 :ile t ( ! latt]1 9 ! area %[n on ! map1 is /ill unrejuv5at$4 ,f>!r d[n-/ream1 ! valley ( ,s& ,creek %[s signs ( rejuv5ation4 ,x may be not$ t a tribut>y ( ,amb] ,creek has good opportunity to capture ,s& ,creek1 = ! latt] fl[s ab\t #be miles be=e rea*+ ! level ( ,amb] ,creek at its junction ) ,elm ,creek4 ,illu/ration3 ,,plate ,,xiii4 ,fig4 #a4 ,,colorado4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,kansas4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xiv4 ,fig4 #a4 ,,p5nsylvania4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,cali=nia4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #aed4--,pr(ile ( a rejuv5at$ /ream4 ,! ,lockatong ,riv] 7,n4 ,j47 to ! head ( ,mud ,run4 ,%\ld ! l[] end ( a tribut>y valley fail to be degrad$ z fa/ z ! valley ( ! ma9 at ! po9t ( junction1 ! tribut>y is out ( topographic adju/m5t ) its ma94 ,falls or rapids may result4 ,:5 ! l[] end ( a tribut>y valley is di/9ctly above ! level ( its ma91 ! =m] is call$ a hang+ valley4 ,hang+ valleys develop$ by /ream erosion alone are n common except j aft] ! recession ( a falls pa/ ! m\? ( a tribut>y4 ,hang+ valleys1 z well z ! *>act]s & relations illu/rat$ by ,figs4 #aeb-aed are crit]ia ( rejuv5ation1 b !y mu/ be appli$ ) discretion4 ,su* pr(iles1 = example1 z t %[n 9 ,fig4 #aed may be develop$ :5 ! rock ( a /ream's b$ is unequally resi/ant1 & hang+ valleys are g5]ally a result ( glaciation 7see ,*apt] ,v74 ,rejuv5at$ /reams sometimes inh]it c]ta9 peculi>ities f _! ag$ ance/ors4 ,?us a rejuv5at$ /ream may intr5* ! me&]s possess$ by ! old /ream :i* prec$$ 7see ,fig4 #a1 ,pl4 ,,xiv1 ne> ,h>risburg1 ,pa471 & intr5*$ me&]s are "o ( ! m>ks ( rejuv5at$ /reams4 ,!y are n uncommon 9 ! ,appala*ian ,m\nta9 regions1 & are kn[n 9 o!r p>ts ( ! _w4 ,! ,se9e & ! ,moselle furni% fur!r illu/rations4#ei ,! hi/ory ( ! new cycle ( erosion inaugurat$ by ! uplift w\ld diff] f t ( ! prec$+ cycle 9 t ! new "o w\ld beg9 ) a dra9age sy/em already develop$4 ,o!r ?+s be+ equal1 !re=e1 ! r$uction ( ! l& w\ld proce$ m rapidly 9 a subsequ5t cycle ?an 9 ! fir/4 ,! recognition ( diff]5t cycles ( erosion1 sep>at$ by uplifts1 is (t5 easy4 ,! pr9ciples involv$ are illu/rat$ by ,fig4 #aee :i* repres5ts an ideal pr(ile ( consid]able l5g? 7say #ej miles74 ,! po9ts a1 a1 & a rea* a common level4 ,bel[ !m !re are areas b1 b1 & b :i* h a ne>ly common elevation1 bel[ :i* are ! %>p valleys d1 d1 & d4 ,! po9ts a1 a1 & a repres5t ! cross-sections ( ridges =m$ by ! outcrops ( lay]s ( h>d rock4 ,if ! cre/s ( ! ridges are level1 ! po9ts a1 a1 & a mu/ repres5t remnants ( an old base-level1 s9ce at no "t aft] a ridge ( h>d rock becomes deeply not*$ does x acquire an ev5 cre/1 until x is base-level$4#fj ,at all e>li] /ages its cre/ is unev54 ,aft] ! cycle repres5t$ by ! remnants a1 a1 & a 0 complet$1 ! region suff]$ uplift4 ,a new cycle repres5t$ by ! pla9 b1 b1 & b 0 well advanc$1 ?\gh n complet$1 :5 ! region 0 aga9 elevat$1 & ! rejuv5at$ /reams began to cut _! valleys d1 d1 & d 9 ! pla9 ( ! previ\s incomplete cycle4 ,! elevations1 c & c 7int]m$iate 9 elevation betwe5 a1 a1 & a1 & b1 b1 & b7 may repres5t ei!r remnants ( ! fir/ base-level pla9 :i* 7 l[]$1 b n oblit]at$1 :ile ! plane b1 b1 b 0 develop+2 or !y may repres5t a cycle int]m$iate betwe5 t dur+ :i* a1 a1 a & b1 b1 b 7 develop$4 ,if ! int]m$iate elevations 7c1 c7 h a common height & level cre/s1 ! presumption w\ld be 9 favor ( ! latt] int]pretation4 ,if !y be num]\s & ( v>y+ heights1 z is possible1 !y may 9 ! field obscure ! planes 7a1 a1 a & b1 b1 b7 develop$ 9 ! diff]5t cycles1 :i*1 9 ! figure1 are di/9ct4 ,illu/ration3 ,fig4 #aee4--;,diagram to illu/rate cycles ( erosion :]e ! b$s are tilt$4 ,if ! /rata involv$ be horizontal ! det]m9ation ( cycles is sometimes less easy4 ,?us 9 ,fig4 #aef1 x is n possible to say :e!r a & a repres5t remnants ( an old base-level1 or :e!r !y repres5t ! orig9al surface f :i* degradation />t$4 ,s1 too1 ! v>i\s b5*es bel[ a1 su* z b1 b1 & b may readily be ! result ( ! sup]ior h>dness ( ! b$s at ?is level4 ,= ! det]m9ation ( successive uplifts 9 ! field x is necess>y to consid] areas ( consid]able size1 & to elim9ate ! topographic effects ( inequalities ( h>dness1 & ( c]ta9 o!r factors to be m5tion$ pres5tly4 ,illu/ration3 ,fig4 #aef4--;,diagram to illu/rate cycles ( erosion :]e ! b$s are horizontal4 ,! inequalities 9 ! dep?s ( ! "y valleys 9 ,figs4 #aee & #aef may be expla9$ on ! supposition t ! deep] ones belong to ma9 /reams1 & ! %all[] ones to tribut>ies4 ,su* a valley z t %[n at e1 ,fig4 #aee1 sugge/s rejuv5ation at ?is po9t2 b f>!r up ! /ream :i* occupies ?is valley1 rejuv5ation might n be app>5t4 ,9 ?is case1 ! ma9 /reams might be fl[+ 9 new valleys1 d1 d1 etc41 :ile ! heads ( _! tribut>ies are /ill fl[+ 9 ! old] valleys ( ! prec$+ cycle 7comp>e ,fig4 #aed & ,fig4 #a1 ,pl4 ,,xiii74 ,x is by ! application ( ! prec$+ pr9ciples t x is kn[n t ! ,appala*ian ,m\nta9s1 aft] be+ fold$1 7 r$uc$ to a p5epla9 7p4 #gf71 ?r\gh\t _! :ole ext5t f ! ,hudson ,riv] to ,alabama4 ,! p5epla9 level is indicat$ by ! level cre/s ( ! ,appala*ian ridges1 %[n 9 cross pr(ile by ! high po9ts ( ,fig4 #aeg4 ,! sy/em 0 !n uplift$1 & 9 ! cycle ( erosion :i* foll[$1 broad pla9s 7 develop$ at a new & l[] level1 correspond+ 9 a g5]al way to ! pla9s b1 b1 & b ( ,fig4 #aee4 ,! pla9s 7 locat$1 = ! mo/ "p1 :]e ! less resi/ant /rata come to ! surface4 ,above !m rose ev5-cre/$ ridges1 ! outcrops ( ! resi/ant lay]s1 :i* _h be5 isolat$ by ! degradation ( ! s(t] b$s betwe54 ,!y con/itute ! pres5t m\nta9 ridges 7! high po9ts ( ,fig4 #aeg74 ,! ev5ness ( _! cre/s1 te/ify+ to ! complet5ess ( ! fir/ p5eplanation1 is %[n 9 ,fig4 #aeh1 :i* repres5ts1 diagrammatically1 a longitud9al pr(ile ( an ,appala*ian ,m\nta9 ridge4 ,! ev5ness ( ! cre/ is int]rupt$ by 7#a7 not*es 7b1 c1 etc41 ,fig4 #aeh7 cut by ! /reams 9 lat] cycles1 & 7#b7 by occasional elevations above ! common level 7monadnocks1 a1 a1 ,fig4 #aeh74 ,! monadnocks are g5]ally r inconspicu\s1 b !re is a notable gr\p ( !m 9 ,nor? ,c>ol9a & ,t5nessee4 ,m\nt ,mit*ell & ,roane ,m\nta9 are examples4 ,:5 long di/ances are consid]$1 ! ridge cre/s dep>t some:at f horizontality4 ,?is is believ$ to be due1 9 "p at lea/1 to de=mations ( ! old p5epla9 dur+ ! uplift :i* inaugurat$ ! second cycle ( erosion4 ,illu/ration3 ,fig4 #aeg4--;,cross-section ( a portion ( ! ,appala*ian ,m\nta9s to illu/rate ! ph5om5a ( erosion cycles4 7,aft] ,rog]s47 ,illu/ration3 ,fig4 #aeh4--;,a diagrammatic longitud9al pr(ile ( an ,appala*ian ,m\nta9 ridge4 ,! ext5t to :i* ! second cycle ( erosion record$ 9 ! pres5t topography _h proce$$ be=e its int]ruption by uplift1 is indicat$ by ! ext5t ( ! valley pla9s 7,fig4 #aeg7 bel[ ! m\nta9 ridges4 ,:ile ^! pla9s 7 be+ develop$ on ! weak rocks1 n>r[ valleys only 7,fig4 #aeh7 7 cut 9 ! resi/ant rocks :i* n[ /ood out z ridges4 ,9 ,fig4 #aeh "s ( ^! valleys are %all[ 7c1 c1 c1 etc471 & b "o ( !m deep4 ,! =m] may be ei!r 7#a7 ! valleys ( /reams :i* cross$ ! h>d lay] at ! beg9n+ ( ! cycle1 & :i* 7 div]t$ be=e _! valleys became deep2 or 7#b7 !y may repres5t ! heads ( valleys n[ work+ back into ! ridges4 ,! deep valley 7b7 repres5ts ! "w ( a /ream :i* has held its c\rse across ! h>d lay] :ile ! latt] 0 be+ isolat$ z a m\nta9 ridge 7comp>e ,figs4 #aca & #acb74 ,deep n>r[s ( ?is sort are (t5 call$ wat]-gaps4 ,simil> valleys1 :e!r %all[ or deep1 f :i* dra9age has be5 div]t$1 are sometimes call$ w9d-gaps4 ,! second cycle ( erosion1 :ile /ill f> f complete1 0 int]rupt$ by uplift 7relative or absolute71 & a new cycle inaugurat$4 ,?is ev5t 0 s rec5t t ! new 7?ird7 cycle has n yet advanc$ f>4 ,illu/ration3 ,fig4 #aei4--,! ,kittat9ny ,m\nta9s & ,delaw>e ,wat]-,gap f ,manunka ,*unk4 7,n4 ,j4 ,geol4 ,surv47 ,rec5tly x has be5 urg$ t ano!r cycle1 int]m$iate betwe5 ! fir/ & second1 is to be recogniz$4#fa ,"s ( ! features j describ$ are illu/rat$ by ,fig4 #aei4 ,! ev5 m\nta9 cre/ 9 ! backgr\nd is ! ,kittat9ny ,m\nta9 ( ,new ,j]sey & its cont9uation 9 ,p5nsylvania4 ,9 common ) o!r correspond+ cre/s x repres5ts ! olde/ record$ base-level 7or p5epla97 ( ! region4 ,! great gap 9 ! m\nta9 is ! ,delaw>e ,wat]-,gap4 ,bel[ ! m\nta9 cre/ !re is ano!r pla91 develop$ 9 a subsequ5t cycle ( erosion1 :ile ! valley pla9 9 ! =egr\nd repres5ts ! "w ( a /ill lat] cycle4 ,illu/ration3 ,fig4 #afj4--,%[+ c]ta9 peculi>ities ( ,appala*ian dra9age4 #a ! ,susquehanna2 #b ! ,potomac2 #c ! ,james2 #d ! ,roanoke2 #e ! ,coosa2 #f ! ,t5nessee2 #g ! ,kana:a2 #h head ( ,new ,riv]2 #i head ( ! ,fr5* ,broad4 ,! olde/ erosion pla9 ( ! ,appala*ian ,m\nta9s1 ! results ( :i* are se5 9 ! ev5-cre/$ ridges s *>act]i/ic ( ! sy/em1 is sometimes call$ ! ,kittat9ny base-level4#a ,x 0 complet$ e>ly 9 ! ,cretace\s p]iod1 & h5ce is sometimes kn[n z ! ,cretace\s base-level4 ,! next l[] pla91 imp]fectly develop$1 has be5 call$ ! ,%5&oah ,pla91#fb f ! ,%5&oah ,valley :]e x is well se5 7,fig4 #acb & ,fig4 #b1 ,pl4 ,,xii74 ,x is to be not$ t ! t]ms base-level & p5epla9 h bo? be5 us$ 9 connection ) ^! old pla9s4 ,grad$ pla9 is equally applicable4 ,! tru? is t ! topographic types repres5t$ by ^! ?ree t]ms grade into "o ano!r4 ,x may be que/ion$ :e!r def9itions %\ld be insi/$ on :i* diff]5tiate ^! types m %>ply ?an ,nature has4 ,_m ( ! peculi>ities ( ! dra9age ( ! ,appala*ian ,m\nta9 sy/em are intimately connect$ ) ! hi/ory j outl9$4 ,?us ?ree great riv]s1 ! ,delaw>e1 ! ,susquehanna1 & ! ,potomac1 h _! s\rces we/ ( ! ,appala*ians prop]1 cross ! sy/em 9 app>5t disreg>d ( ! /ructure1 & fl[ into ! ,atlantic4 ,! ,james & ,roanoke head f> to ! we/1 al?\gh n beyond ! m\nta9 sy/em1 & fl[ ea/w>d1 :ile ! ,new ,riv] 7lead+ to ! ,kana:a7 f>!r s\?1 heads ea/ ( ! m\nta9-folds1 & fl[s nor?we/w>d across ! alt]nat+ h>d & s(t b$s ( ! :ole ,appala*ian sy/em1 to ! ,ohio 7,fig4 #afj74 ,! ,fr5* ,broad1 a tribut>y to ! ,t5nessee1 has a simil> c\rse4 ,su* /reams are cle>ly n 9 /ructural adju/m5t1 & af=d good opportunities = piracy4 ,_! c\rses 7 app>5tly assum$ dur+ ! "t ( ! ,kittat9ny base-level1 :5 ! /reams _h s l[ a gradi5t z n to be affect$ by ! /ructure 7p4 #aej74 ,elevation rejuv5at$ !m1 & !y h held _! c\rses 9 succe$+ cycles across b$s ( unequal resi/ance1 ?\gh small] /reams h become some:at ?or\ghly adju/$4 ,cru/al de=mations h also help$ !m to hold _! c\rses1 = ! ,cretace\s p5epla9 seems to h be5 tilt$ to ! s\!a/ at its nor!rn end1 & to ! s\?we/ at its s\!rn1 :5 ! succe$+ cycle began4 ,/reams :i* hold _! e>ly c\rses 9 spite ( *anges :i* h tak5 place s9ce _! c\rses 7 assum$ are said to be antec$5t4 ,!y ant$ate ! cru/al movem5ts :i*1 b = pre-exi/5t /reams1 w\ld h giv5 orig9 to a diff]5t arrangem5t ( riv] c\rses4 ,z a result ( cru/al movem5ts1 !re=e1 a consequ5t /ream may become antec$5t4 ,ma/] /reams are m likely to hold _! c\rses1 & !re=e to become antec$5t1 ?an subord9ate ones4 ,! uplift ( base-level$ b$s1 especially if ! b$s are tilt$ s z to br+ lay]s ( unequal resi/ance to ! surface at frequ5t int]vals1 af=ds conditions favorable = ext5sive adju/m5t4 ,! num]\s w9d-gaps 9 ! m\nta9 ridges1 repres5t+ ! ab&on$ c\rses ( m9or /reams1 & ! less num]\s wat]-gaps1 :i* indicate ! resi/ance ( l>ge /reams to /ructural adju/m5t1 are in/ructive witnesses ( ! ext5t to :i* adju/m5t has gone4 ,s ext5sive has be5 ! adju/m5t among ! /reams ( ! ,appala*ian ,m\nta9s t !re is probably no consid]able /ream 9 ! :ole sy/em :i* has n ga9$ or lo/ ?r\gh its own or its neighbors' piracy4 ,! hi/ory ( ! riv]s ( ! ,appala*ian ,m\nta9s has be5 fur!r complicat$ by a consid]able am\nt ( w>p+ dur+ ! p]iods ( uplift4#fc ,illu/ration3 ,figs4 #afa1 #afb4--;,diagrams to illu/rate ! effect ( cru/al w>p+ on /ream erosion4 ,! dott$ l9es repres5t ! pr(iles ( ! /reams be=e de=mation2 ! full l9es1 aft]4 ,erosion w be /imulat$ betwe5 a & b 9 ea* case1 & betwe5 c & d 9 ,fig4 #afb4 ,bel[ b1 ,fig4 #afa1 ! /ream w be dr[n$1 & erosion !re=e /opp$4 ,erosion w also be /opp$ or ret>d$ above a1 betwe5 b & c1 & bel[ d 9 ,fig4 #afb4 ,s9k+4--,! l& on :i* a riv] sy/em is develop$ may be depress$ relative to sea-level4 ,9 ?is case ! sea w\ld occupy ! l[] ends ( valleys1 conv]t+ !m into bays & e/u>ies4 ,a /ream 9 ?is condition is said to be dr[n$4 ,( dr[n$ riv]s !re are _m examples along ! ,atlantic coa/4 ,?us ! ,/4 ,lawr5ce ,riv] is dr[n$ up to ,montreal1 & ! ,hudson up to ,albany4 ,if ! dr[n$ portion ( ! latt] valley 7 n s n>r[1 x w\ld be a bay4 ,delaw>e & ,*esapeake ,bays1 z well z _m small] ones1 bo? nor? & s\?1 are likewise ! dr[n$ ends ( riv] valleys 7see figures1 ,*apt] ,,vi74 ,if all p>ts ( a dra9age bas9 sank equally1 ! velocities ( ! /reams above ! limit ( dr[n+ w\ld n be *ang$1 = ! gradi5ts w\ld rema9 ! same z be=e4 ,! fact t a riv]'s *annel is bel[ sea-level is n to be tak5 z pro( t ! valley is dr[n$4 ,?us ! bottom ( ! *annel ( ! ,mississippi is z mu* z #ajj feet bel[ ! level ( ! ,gulf1 "s #bj miles above ,new ,orleans4#fd ,diff]5tial movem5t4 ,w>p+4--,:]e a l& surface on :i* a riv] sy/em is e/abli%$ suff]s w>p+1 "s p>ts go+ up & o!rs d[n1 ! opposite movem5ts be+ ei!r absolute or relative1 v>i\s ph5om5a w\ld result4 ,?is may be illu/rat$ by ! accompany+ diagrams 7,figs4 #afa & #afb71 :]e ! pr(iles ( ! /reams are repres5t$ z w>p$ f ! positions repres5t$ by ! dott$ l9es1 to ! positions %[n by ! full l9es4 ,! velocity w be accel]at$ bel[ ! po9ts ( diff]5tial elevation 7betwe5 a & b1 ,fig4 #afa1 & betwe5 a & b1 & c & d1 ,fig4 #afb71 b *eck$ above 7above a1 & betwe5 b & c1 ,fig4 #afb74 ,above an elevation :i* notably *ecks its fl[1 a /ream is pond$4 ,if ! pond+ is slight1 a m>% may develop above ! ob/ruction2 if m consid]able1 a lake is =m$4 ,lakes ( ?is class are likely to be %ort-liv$1 s9ce ! pond$ wat]s are likely to soon ov]fl[ & l[] _! outlet s z to dra9 ! lake4 ,! elevation :i* ponds ! /ream may be great en\gh & rapid en\gh s t ! result+ lake f9ds an outlet by "s c\rse o!r ?an t orig9ally foll[$ by ! /ream4 ,:]e a /ream holds its c\rse across an uplift a?w>t its valley1 ei!r ) or )\t pond+1 x becomes an antec$5t /ream 7see p4 #afi71 s9ce x has a c\rse assum$ be=e ! late/ de=mation ( ! cru/ & 9 app>5t disreg>d ( pres5t surface configuration4 ,?us ! ,columbia ,riv] holds its antec$5t c\rse across areas :i* h be5 uplift$ 7diff]5tially7 hundr$s & ev5 ?\s&s ( feet4#fe ,"s ( ! /rik+ sc5ic features ( ?is noble valley are ! result ( ^! *anges 9 ! c\ntry ?r\gh :i* x fl[s4 ,a less] /ream w\ld h be5 div]t$1 z _m ( its tribut>ies h be54 ,ev5 its c\rse across ! ,cascade ranges is believ$ to be antec$5t4#ff ,illu/ration3 ,figs4 #afc1 #afd4--,piracy /imulat$ by w>p+4 ,uplift along axis #a-b4 ,ano!r peculi>ity ( valleys & /reams result+ f *anges ( level is illu/rat$ 9 ,fig4 #b1 ,pl4 ,,xiv 7s\!rn ,cali=nia74 ,! ma9 valleys ( ?is "p ( ! coa/ 7 develop$ :5 ! l& /ood consid]ably high] ?an n[4 ,lat] ! subsid5ce ( ! coa/ conv]t$ ! l[] ends ( ! valleys into bays or fiords4 ,! bays 7 !n trans=m$ into lagoons by deposition4 ,subsequ5t rise ( ! l& or depression ( ! sea all[$ ! dra9age f ! old lagoons to cut across ! deposits :i* _h conv]t$ ! bays into lagoons4 ,! result is an old1 wide valley above1 sugge/$ by a "y "o bel[4 ,if ! w>p+s 7 consid]able1 mu* m decisive *anges 9 dra9age w\ld result4 ,suppose ! dra9age ( a giv5 region to be repres5t$ by ! /reams 9 ,fig4 #afc4 ,if !re is uplift along ! axis #a-b1 t "p ( ac above ! axis ( uplift w\ld be pond$1 or at lea/ h its velocity *eck$1 :ile ! fl[ ( "s ( ! tribut>ies ( d w\ld be accel]at$1 & might "w back & capture ! o!r /ream 7,fig4 #afd74 ,cru/al w>p+ 0 "o ( ! conditions "u :i* ! ,t5nessee a*iev$ its pres5t anomal\s c\rse1 & its hi/ory#fg is illu/rative ( ! complex *anges :i* dra9age suff]s :5 w>p+ affects ! area :]e ! rock /ructures are ( unequal resi/ance4 ,at ! close ( ! ,cretace\s cycle ( erosion1 :5 ! ,appala*ian ,m\nta9s _h be5 r$uc$ to a p5epla91 ! wat]s fall+ 9 ! area n[ dra9$ by ! upp] c\rse ( ! ,t5nessee fl[$ s\?-s\?-we/ to ! ,gulf 9 a /ream 7! ,appala*ian ,riv]1 a1 ,fig4 #afe7 ! l[] "p ( :i* _h ! g5]al position ( ! ,coosa & ! ,alabama4 ,to ! we/ ( ! ,appala*ian ,riv]1 %ort] /reams fl[$ we/ & s\?we/ into ! ,mississippi embaym5t 7,fig4 #afe7 by c\rses :i* are n n[ def9itely kn[n4 ,! succe$+ cycle ( erosion 0 inaugurat$ by uplift & de=mation ( ! p5epla94 ,! axis ( greate/ elevation 7,,ab1 ,fig4 #aff7 0 ne>ly p>allel to ! ,appala*ian ,riv]1 & ! effect ( ! diff]5tial uplift 0 to impose a great] task on ?is riv] 7a1 ,fig4 #aff71 :i* fl[$ along ! axis ( uplift1 ?an ^u ! riv]s :i* fl[$ we/w>d & s\?we/w>d to ! ,mississippi embaym5t4 ,! result 0 t ! /ronge/ ( ! s\?we/]ly fl[+ /reams work$ its head back into ! dra9age bas9 ( ! ,appala*ian ,riv]1 & captur$1 "o by "o1 ! head-wat]s ( its we/]ly tribut>ies1 e/abli%+ "s su* dra9age relations z are %[n 9 ,fig4 #aff4 ,/ill lat]1 aft] ! l& area ( ! region _h be5 consid]ably ext5d$ by ! )drawal ( ! sea1 ! ,appala*ian ,riv] itself 0 rea*$ by ! invad+ /ream1 & its wat]s c>ri$ away to ! ,mississippi ,bay by a c\rse ! l[] "p ( :i* is ?\ght to h correspond$ approximately ) ! c\rse ( ! pres5t ,black ,riv] 7b1 ,fig4 #afg74 ,illu/ration3 ,fig4 #afe4--,%[s ! g5]al position ( ! ma9 dra9age l9es 9 ! s\!rn ,appala*ians at ! close ( ! ,cretace\s cycle ( erosion4 ,! l[] "p ( /ream b is made to foll[ ! c\rse ( a portion ( ! pres5t ,t5nessee4 ,illu/ration3 ,fig4 #aff4--,%[s ! g5]al position ( ! ma9 dra9age l9es 9 ! s\!rn ,appala*ians1 aft] ! capture ( ! we/]ly tribut>ies ( ! ,appala*ian ,riv] by /ream b4 ,comp>e ,fig4 #afe4 ,illu/ration3 ,fig4 #afg4--;,a /age lat] ?an t %[n 9 ,fig4 #aff4 ,! sea is repres5t$ z hav+ )drawn f a consid]able area :i* 0 subm]g$ at e>li] /ages 7,figs4 #afe1 #aff74 ,illu/ration3 ,fig4 #afh4--,%[s ! f9al *ange :i* result$ 9 ! pres5t c\rse ( ! ,t5nessee4 ,! l& is repres5t$ z some:at high] ?an n[4#fh ,/ill lat] !re 0 fur!r de=mation :i* caus$ additional *anges 9 ! dra9age4 ,! :ole region 0 uplift$1 relatively if n absolutely1 b ! uplift 0 diff]5tial1 be+ greate/ along ! axis repres5t$ by ,,ab1 ,fig4 #afg4 ,! effect ( ! de=mation 0 to /imulate ! tribut>ies ( ! ,ohio fl[+ nor? f ?is axis4 ,_! gr[? 0 fur!r accel]at$ by ! weakness ( ! /rata ov] :i* !y ran4 ,at ! same "t1 ! uplift to ! s\? l$ ! s\?we/]ly fl[+ /ream 7b1 ,fig4 #afg7 to discov] relatively h>d b$s ( rock 9 its l[] c\rse1 & ^! b$s ret>d$ its d[n-cutt+4 ,! result 0 t a tribut>y ( ! ,ohio 7a1 ,fig4 #afg7 f9ally tapp$ ! ma9 /ream fl[+ to ! s\?we/ 7b1 ,fig4 #afg7 & c>ri$ its upp] "p ov] to ! ,ohio 7,fig4 #afh74 ,?is 0 ! beg9n+ ( ! pres5t ,t5nessee4 ,,! ,,aggradational ,,"w ,,( ,,runn+ ,,wat]4 ,pr9ciples involv$4--,s9ce deposition results f ! failure ( transportation1 ! factors :i* control transportation also influ5ce deposition4 ,transportation by /reams is det]m9$ l>gely by velocity1 & ! mo/ important factors influ5c+ velocity are slope1 volume1 & load 7p4 #aae74 ,( ^! ! fir/ two are usually ( great] importance ?an ! ?ird4 ,a /ream is said to be load$ :5 x has all ! s$im5t x c c>ry2 x is load$ ) f9e mat]ial :5 x has all ! f9e mat]ial x c c>ry1 & ) co>se mat]ial :5 x has all ! co>se x c transport4 ,a /ream load$ ) co>se mat]ial fl[s m swiftly ?an "o load$ ) f9e1 = a l>g] p]c5tage ( a /ream's en]gy c be utiliz$ 9 c>ry+ f9e mat]ial ?an co>se1 & h5ce a l>g] p]c5tage ( ! en]gy ( a /ream :i* c>ries a load ( ! latt] w express itself 9 velocity4 ,deposition takes place :5ev] a /ream f9ds itself ) m load ?an x c c>ry1 & is an expression ( ! /ream's refusal to rema9 ov]load$4 ,a /ream may become ov]load$ 9 v>i\s ways4 ,x might at fir/ seem unnecess>y to inquire :e!r a /ream may be ov]load$ at its s\rce1 b ! "q is n necess>ily to be answ]$ 9 ! negative4 ,! s\rce ( a /ream is n always a def9ite po9t4 ,9 a g5]al way x may be said t ! s\rce ( ! normal /ream is at t po9t 9 its valley :]e ! bottom is z l[ z ! gr\nd-wat] level ( ! region4 ,b s9ce ! gr\nd-wat] level is n con/ant 7p4 #ga7 ! s\rce ( a /ream is likely to be f>!r up its valley 9 a wet season ?an 9 a dry "o 7p4 #gb74 ,aft] a heavy %[]1 ! run-(f desc5ds to ! axis ( ! valley f ! slopes on all sides1 & tempor>ily ! /ream beg9s above ! po9t :i* m>ks ev5 its wet-season s\rce4 ,if "u su* circum/ances ! slopes ab\t ! head ( ! valley are notably /eep] ?an ! slope ( ! valley itself1 z !y frequ5tly are1 ! wat] fl[+ d[n !m may ga!r an am\nt ( mat]ial :i* x _c c>ry aft] x rea*es ! bottom ( ! valley4 ,?is may be ! case at1 or ev5 above1 ! po9t :i* m>ks ! s\rce ( ! p]man5t /ream4 ,x is1 !re=e1 possible = a /ream to be ov]load$ at its s\rce1 if we take ! s\rce to be ! po9t :5ce ! wat] p]man5tly fl[s4 ,deposition may1 !re=e1 be tak+ place 9 a valley at ! head ( its p]man5t /ream1 or tempor>ily ev5 9 ! valley above x4 ,/reams issu+ f glaci]s sometimes h m load ?an !y c c>ry aft] !y escape f ! ice4 ,if ! /ream be reg>d$ z beg9n+ at ! po9t :]e x issues f b5ea? ! ice x may be ov]load$ at its s\rce4#fi ,"u c]ta9 circum/ances1 a /ream may ov]load itself4 ,?us if a /ream load$ ) co>se detritus rea*es a portion ( its valley :]e f9e mat]ial is accessible 9 abundance1 "s ( ! velocity :i* is help+ to c>ry ! co>se may be us$ 9 pick+ up & c>ry+ ! f9e4 ,?is r$uces ! velocity1 & s9ce ! /ream already _h all ! co>se mat]ial x c\ld c>ry1 r$uction ( velocity mu/ result 9 deposition4 ,x foll[s t :5 a /ream fully load$ ) co>se mat]ial picks up f9e1 x becomes ov]load$1 s f> z ! co>se mat]ial is conc]n$4 ,aga91 tribut>ies may ov]load _! ma9s4 ,:ile tribut>ies are usually small] ?an _! ma9s1 !y frequ5tly h high] gradi5ts1 & ! small] /ream ( high] gradi5t may br+ to ! l>g] /ream ( l[] gradi5t m mat]ial ?an ! latt] c c>ry away4 ,?us deposition may take place at ! po9t ( junction ( tribut>ies ) _! ma9s4 ,?is may g s f> z to pond ! latt] en\gh to cause its expansion into a riv]-lake4 ,lake ,pep91 9 ! ,mississippi ,riv] at ! m\? ( ! ,*ippewa 79 ,wis471 is an example4 ,/reams may become ov]load$ by los+ velocity or volume1 or bo?4 ,decrease 9 velocity is br\ght ab\t ei!r by decrease 9 declivity or 9 volume4 ,9 g5]al1 /reams h l[] gradi5ts & great] volumes 9 _! l[] c\rses ?an 9 _! upp]1 & ^! two elem5ts affect velocity 9 diff]5t ways4 ,if ! increase 9 volume be n en\gh to c\nt]balance ! decrease 9 declivity1 z is (t5 ! case1 a /ream :i* is load$ 9 its upp] c\rse w deposit 9 its l[]4 ,! decrease ( velocity at ! deb\*ure ( a /ream almo/ always leads to deposition4 ,decrease 9 velocity z ! result ( decrease 9 volume is less common4 ,:5 decrease 9 volume occurs1 x may be ! result ( 7#a7 evaporation1 7#b7 ! absorption ( wat] into ! b$ ( ! /ream1 or 7#c7 bran*+--! giv+ (f ( di/ribut>ies4 ,:ile evaporation is go+ on ev]y:]e1 ! dim9ution ( a /ream by ?is means is usually m ?an balanc$ by ! increase f tribut>ies1 ra9fall1 & spr+s2 b 9 arid regions a v diff]5t condition ( ?+s sometimes exi/s4 ,if m\nta9s 9 an arid region be capp$ ) sn[1 its melt+ supplies ! /reams dur+ ! melt+ season4 ,z ! /reams fl[ out f ! m\nta9s ?r\gh dry regions1 !y receive little or no increm5t f ra9fall1 tribut>ies1 or spr+s1 & evaporation r$uces ! volume ( wat]1 or ev5 dissipates x altoge!r4 ,absorption ( wat] into ! b$ ( ! /ream (t5 accompanies evaporation4 ,r$uction ( volume by evaporation & by absorption is especially common 9 arid regions4 ,:]ev] load$ /reams are r$uc$ 9 volume1 :e!r by evaporation or absorption1 deposition takes place4 ,! ?ird way by :i* velocity is decreas$ z ! result ( decreas+ volume is illu/rat$ at ! deb\*ures ( _m /reams4 ,ne> ! ,gulf1 = example1 ! ,mississippi bran*es repeat$ly 7see ,fig4 #aij74 ,! same ph5om5a are (t5 se5 :]e "o /ream jo9s ano!r 7,fig4 #afi74 ,individually ! di/ribut>ies are mu* small] ?an ! ma9 /ream be=e !y sep>at$ f x1 & because !y are small] _! comb9$ surfaces are great]1 & ! am\nt ( en]gy consum$ 9 ! friction ( fl[ is increas$4 ,! velocity ( ! wat] & its c>ry+ p[] are1 !re=e1 r$uc$4 ,?us ! bran*+ ( /reams gives rise to deposition1 & :]e deposition takes place ! gradi5t ( ! /ream is r$uc$1 & ?is occasions /ill fur!r deposition4 ,! s$im5t :i* fills up ! *annel & *ecks ! fl[ f9ally compels ! /ream1 or "s "p ( x1 to transgress its banks4 ,deposition1 !re=e1 favors ! developm5t ( di/ribut>ies1 & ! developm5t ( di/ribut>ies 9 turn favors deposition4 ,illu/ration3 ,fig4 #afi4--;,delta ( ! ,*elan ,riv] at its junction ) ! ,columbia4 ,%[s ! t5d5cy ( /reams to di/ribute :]e active deposition is 9 progress4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,! =ego+ /atem5ts make x cle> t a /ream may be erod+ 9 "o "p ( its valley :ile x is deposit+ 9 ano!r1 & t erosion may alt]nate ) deposition 9 ! same place1 on acc\nt ( fluctuations 9 volume1 &1 !re=e1 9 velocity ( ! /ream4 ,x w be se5 9 ! sequel t erosion & deposition may be tak+ place at ! same "t 9 ! same "p ( ! valley4 ,! activities ( a riv] are s nicely balanc$ t slight di/urbance at "o po9t causes di/urbance at all po9ts bel[4 ,! deposits4 ,types4--,turn+ f ! pr9ciples :i* und]lie riv] deposition to ! deposits !mselves1 !y are f\nd to occur 9 v>i\s situations4 ,runn+ wat] usually desc5ds f /eep] slopes above to g5tl] slopes bel[1 & ends at ! sea1 or 9 a lake or inl& bas94 ,:]ev] !re is a sudd5 decrease 9 its gradi5t1 z at ! base ( a hill1 ridge1 or m\nta91 runn+ wat] is likely to leave a l>ge "p ( its load1 build+ an alluvial fan or cone 7,figs4 #fg1 #fh1 & ,pl4 ,,vi74 ,ev5 :]e !re is no sudd5 decrease 9 ! gradi5t ( a /ream1 !re is likely to be a gradual "o1 & 9 spite ( ! fact t ! increas$ volume ( a /ream 9 its l[] c\rse t5ds to ov]come ! effect ( dim9i%$ gradi5t on velocity1 deposition is likely to take place z ! gradi5t is r$uc$4 ,deposits occasion$ by ! gradual r$uction ( a /ream's velocity (t5 h great ext5t 9 ! direction ( a /ream's fl[4 ,!y cov] ! flood pla9s ( /reams1 mak+ !m alluvial pla9s 7,fig4 #gc74 ,:5 a /ream rea*es ! sea or a lake its curr5t is de/roy$ & its load dropp$1 unless tak5 9 *>ge by ! waves & curr5ts ( ! /&+ wat]4 ,s$im5t accumulat$ 9 quantity at ! deb\*ures ( /reams gives rise to deltas 7,figs4 #afi1 #ahg74 ,alluvial cones & fans1 alluvial pla9s1 & deltas1 are ! pr9cipal types ( riv] deposits4 ,ap>t f ^! well-def9$ types !re are b>s 9 ! *annels ( deposit+ /reams1 & mu* ill-def9$ alluvium :i* does n all[ ( ready classification4 ,alluvial fans & cones4--,! only di/9ction betwe5 ! alluvial fan & ! alluvial cone is "o ( slope1 ! cones 7!y are b half-cones at be/7 be+ /eep] ?an ! fans4 ,alluvial fans & cones h _! mo/ /rik+ developm5t :]e tempor>y torr5ts1 occasion$ by %[]s or ! rapid melt+ ( sn[1 issue f m\nta9 rav9es4 ,su* /reams usually c>ry heavy loads ( detritus1 ! co>s] "p ( :i* is likely to be deposit$ at ! base ( ! m\nta9 slope4 ,cones & fans built by su* /reams h a p]iodic r ?an a /eady gr[?4 ,at ! beg9n+ ( its developm5t ! mat]ial ( ! alluvial cone is deposit$ mu* z 9 a talus cone 7comp>e ,fig4 #agj ) ,figs4 #fg & #fh74 ,its deposition *okes ! *annel ( ! /ream1 & "s ( ! wat] !n seeks new c\rses to "r & left ( ! apex ( ! deposit4 ,?is exp&s ! area ( deposition to "r & left1 :ile ! wat] :i* fl[s ov] x l5g!ns x 9 ! direction ( fl[4 ,! c\rse & behavior ( ! wat] aft] rea*+ an alluvial cone is in/ructive4 ,z its velocity is *eck$1 deposition (t5 takes place 9 ! *annel1 dim9i%+ its capacity4 ,z ! *annel is fill$ up1 ! wat] t5ds to ov]fl[ on ei!r side4 ,! ov]fl[+ wat]1 be+ %all[1 has s little velocity t mu* ( its load is dropp$ on ei!r m>g9 ( ! *annel1 build+ up levees4 ,! wat] ev] & anon breaks ?r\gh ! levees1 giv+ rise to di/ribut>y /reams1 ea* ( :i* aggrades its *annel & builds its own m9iature levees 7,fig4 #aga74 ,n r>ely ?is process ( *annel-fill+ & levee-build+ goes on until ! *annels ( ! little rivulets are above ! g5]al level ( ! cone on :i* !y re/4 ,! rivulet !n runs 9 a groove on ! cre/ ( a little ridge4 ,! *annels on ! surfaces ( fans & cones are fewe/ & deepe/ at _! heads1 & m num]\s & %all[] bel[4 ,9 "s cases ! surface-wat] disappe>s altoge!r be=e ! out] bord] ( ! fan is rea*$1 by s9k+ into ! dbris4 ,illu/ration3 ,fig4 #agj4--;,a talus cone4 ,nor? ,gre5l& ,coa/4 ,! talus cone rea*es ! sea-level4 ,drawn f photograph4 ,alluvial fans & cones h v>i\s =ms1 & (t5 atta9 consid]able dim5sions4 ,_! angles ( slope dep5d on ! am\nt ( r$uction ( velocity :i* ! deposit+ wat] suff]s1 & ! am\nt & k9d ( load :i* x c>ries4 ,! maximum slope ( ! cone is ! angle at :i* ! loose mat]ial involv$ w lie4 ,! m9imum slope ( ! fan1 on ! o!r h&1 approa*es horizontality4 ,if _m alluvial fans develop 9 proximity to "o ano!r1 z at ! base ( a m\nta9 range1 !y may exp& lat]ally until !y m]ge4 ,a long succession ( !m may ?us give rise to an ext5sive alluvial pi$mont pla91 or a comp\nd alluvial fan4 ,! l[] edge ( su* a fan is (t5 some:at lobate4 ,su* pla9s exi/ along ! bases ( _m m\nta9 ranges 7,pl4 ,,vi71 & may be se5 9 m9iature ev5 along l[ ridges4 ,illu/ration3 ,fig4 #aga4--,m9iature levees on an alluvial cone4 ,slope ( ,gray ,peak1 ,colo4 7,r4 ,t4 ,*amb]l947 ,a p]man5t /ream1 z well z a tempor>y "o1 may develop an alluvial fan at ! base ( a m\nta9 slope2 b s9ce ! m\nta9 c\rse ( ! =m] is likely to be less /eep ?an t ( ! latt]1 its wat]s suff] a correspond+ly less r$uction ( velocity at any "o po9t4 ,! fan ( ! p]man5t /ream is !re=e likely to be relatively flat1 & to /ret* f> d[n ! valley4 ,su* fans grade into valley pla9s4 ,f ! g5]al pr9ciples already discuss$1 x is cle> t well-develop$ fans g ) relatively y\?ful /ages ( erosion1 & belong normally to ! upp] p>ts ( dra9age l9es4 ,ill-def9$ alluvium4--,!re is a widespread mantle ( alluvial mat]ial deposit$ by runn+ wat] :i* 0 n organiz$ into di/9ct /reams4 ,! wat] :i* runs d[n smoo? slopes 9 %eets dur+ %[]s c>ries f9e e>?y matt]1 z well z "s t is co>s]4 ,^! mat]ials are l>gely deposit$ at ! bases ( ! slopes1 =m+ basal accumulations ( great] or less ext5t1 comp>able 9 orig9 to alluvial fans4 ,a relatively small am\nt ( ! slope wa% is c>ri$ f> out f ! base ( ! declivities4 ,x is n easy to realize ! ext5t to :i* ?is process is tak+ place4 ,!re is h>dly a slope )\t loose mat]ial1 & !re is h>dly an acre ( l[ l& bel[ a slope on :i* runn+ wat] has n deposit$ s$im5t wa%$ d[n f above4 ,:5 x is rememb]$ t ?is is z true ( g5tle slopes & _! surr\nd+s z ( /eep slopes1 ?\gh p]haps n to ! same ext5t1 & t a v l>ge "p ( ! e>?'s surface is made up ( s5sible slopes1 or ( flats at _! bases1 "s idea ( ! aggregate effect may be ga9$4 ,!re is ano!r way ( look+ at ! same "q4 ,e>?y matt] is be+ cont9ually transf]r$ f l& to sea1 & *iefly f high l&4 ,r>ely does x />t f any po9t di/ant f ! %ore & move un9t]rupt$ly to x4 ,x is transport$ a %ort di/ance & lodg$1 to be aga9 pick$ up1 c>ri$ =w>d ano!r /ep 9 its j\rney1 & lodg$ aga94 ,= a v l>ge "p ( ! e>?'s surface x w\ld be true to say t its mantle rock is mat]ial 9 transit f high] l& to ! sea4 ,alluvial pla9s4--,mo/ /reams1 :e!r head+ 9 m\nta9s or n1 h g5tl] gradi5ts 9 _! l[] c\rses ?an 9 _! upp]1 & 9 spite ( increas+ volume are usually unable to c>ry to _! deb\*ures all ! mat]ial ga!r$ above4 ,! excess ( load is dropp$ *iefly on ! flood-pla9s ( ! /reams & con/itutes !m alluvial pla9s4 ,! mak+ ( an alluvial pla9 usually involves bo? erosion & deposition4 ,:5 a /ream has cut its *annel to grade1 d[nw>d erosion ceases1 or m exactly1 d[nw>d cutt+ is1 on ! av]age1 c\nt]balanc$ by deposition4 ,s long z a /ream is cutt+ d[nw>d rapidly1 x c>ries away :atev] dbris desc5ds ! side slopes4 ,:5 x approa*es grade1 ! dbris :i* desc5ds ! side slopes t5ds to accumulate at _! bases1 & ! ,v-%ap$ cross-section ( ! valley becomes ,u-%ap$ 7see ,fig4 #agb74 ,at ab\t ! same "t ! /ream beg9s to me&]1 =1 hav+ lo/ some?+ ( its =m] velocity1 x is m easily turn$ f side to side4 ,z x beg9s to me&]1 x wid5s ! bottom ( its valley4 ,?is is ! initial /age 9 ! developm5t ( ! valley flat 7#b & #c1 ,fig4 #agb74 ,9 its me&]+ ! /ream encroa*es on ! talus accumulations at ! bases ( its valley's slopes4 ,! side-cutt+ may remove all ! loose dbris & ev5 und]cut ! bluff z at a1 ,fig4 #agc4 ,! /ream's me&]s %ift _! positions f "t to "t s t ! valley flat is successively wid5$ at diff]5t po9ts4 ,by lat]al planation1 !re=e1 a /ream t5ds to develop a flat z soon z x rea*es grade4 ,?is is ! initial "p ( erosion 9 ! mak+ ( a riv] flat1 b a flat develop$ by erosion alone is n an alluvial pla94 ,s soon z ! flat develop$ by a /ream exce$s ! wid? ( its *annel1 ! wat] 7except 9 times ( flood7 does n cov] x all at ! same "t4 ,on any "p :i* x tempor>ily ab&ons1 "s dbris 7alluvium7 is likely to be left4 ,?is deposit ( alluvium con/itutes ! valley flat an alluvial pla9 7,fig4 #agd74 ,x w be se5 t ! valley flat is commonly an alluvial pla9 f ! beg9n+4 ,illu/ration3 ,fig4 #agb4--;,diagram illu/rat+ ! trans=mation ( a ,v-%ap$ valley into a ,u-%ap$ valley4 ,illu/ration3 ,fig4 #agc4--;,diagram to illu/rate ! wid5+ ( a valley flat by erosion4 ,comp>e #c1 ,fig4 #agb4 ,once ! valley flat & alluvial pla9 are begun1 _! fur!r developm5t is easily foll[$4 ,! /ream 9 flood ov]fl[s ! banks ( its *annel4 ,! velocity ( ! ov]fl[+ wat] is r$uc$1 & if x has mu* load a "p ( x w be dropp$ & ! pla9 aggrad$4 ,meantime me&]+ & lat]al planation cont9ue4 ,?us ! flood-pla9 is wid5$ by erosion1 & aggrad$ by alluviation1 ! two processes go+ on simultane\sly4 ,illu/ration3 ,fig4 #agd4--;,an alluvial pla94 ,! diagram sugge/s ! relative importance ( lat]al planation & alluviation 9 ! developm5t ( ! flat4 ,flood-pla9s1 *iefly ! result ( planation1 b p>tly ( aggradation1 are a normal feature ( riv] valleys1 aft] a c]ta9 /age ( developm5t has be5 rea*$4 ,?is /age is t at :i* d[nw>d erosion becomes slight 9 comp>ison ) lat]al erosion4 ,x foll[s t an alluvial pla9 normally beg9s its developm5t :]e ! valley is fir/ br\ght to grade1 t is1 9 its l[] c\rse4 ,z ! developm5t ( ! valley goes on1 ! head ( ! flood-pla9 advances up-/ream1 & at ! same "t its old] p>ts become wid]4 ,illu/ration3 ,fig4 #age4--;,diagrammatic repres5tation ( a flood pla9 develop$ by alluviation only4 ,flood-pla9s due to alluviation only4--,exceptionally1 an alluvial pla9 is develop$ by deposition only4 ,?us if a /ream becomes ov]load$ :ile its valley is /ill n>r[1 z sometimes happ5s1 deposition foll[s1 &1 z aggradation proce$s1 ! n>r[ valley acquires a progressively wid] bottom 7,fig4 #age74 ,wide valley pla9s are sometimes develop$ 9 ?is way4 ,flood pla9s develop$ :olly by alluviation are sometimes =m$ "u conditions :i* are indep5d5t ( ! /age ( a valley's developm5t4 ,?us if a /ream sudd5ly acquires an exceptional supply ( detritus 9 its upp] c\rse1 ! developm5t ( an alluvial pla9 beg9s imm$iately bel[ ! po9t ( ov]load+4 ,! ov]load might be acquir$ 9 v>i\s ways4 7#a7 ,if a /ream taps ano!r 7piracy7 :i* c>ries a l>ge quantity ( s$im5t1 c>ry+ (f bo? wat] & s$im5t to a *annel ) a l[] gradi5t1 deposition may take place :]e1 "u ! e>li] conditions1 !re 0 none4 7#b7 ,aga91 :5 a /ream cuts ?r\gh a b>ri] ne> its head wat]s1 its velocity1 &1 !re=e1 its erod+ p[]1 may be s increas$ 9 its upp] c\rse t s$im5t en\gh is acquir$ to occasion deposition bel[1 :]e none took place be=e4 7#c7 ,9 work+ back ?r\gh =mations ( v>y+ degrees ( resi/ance1 a /ream's head may pres5tly rea* a =mation or a region :i* yields abundant s$im5t1 ev5 ?\gh !re 0 no especial b>ri] bel[4 7#d7 ,if an advanc+ glaci] %\ld rea* ! head wat]s ( a /ream1 its dis*>ge to ! /ream w\ld greatly increase ! load ( ! latt]1 &1 al?\gh its volume w\ld be augm5t$ at ! same "t1 deposition might result4 ,z a matt] ( fact1 /reams c>ry+ glacial dra9age are usually aggrad+ /reams4 ,9 g5]al1 any?+ :i* greatly increases ! load ( a /ream ne> its head is likely to cause deposition1 & s ! developm5t ( a flood pla91 at "s po9t f>!r d[n ! valley4 ,illu/ration3 ,fig4 #agf4--;,ana/omos+ ( a deposit+ /ream4 ,yahtse ,riv]1 ,alaska4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,/reams :i* are actively aggrad+ _! valleys are likely to ana/omose 7,figs4 #agf1 #agg74 ,?is results f ! fill+ ( ! *annels until !y are too small to accommodate all ! wat]4 ,! latt] !n breaks out ( ! *annel at few or _m po9ts4 ,! new *annels ?us e/abli%$ suff] ! same fate4 ,illu/ration3 ,fig4 #agg4--;,ana/omos+ ( ! ,platte ,riv]1 ,dawson ,co41 ,neb4 7,u4 ,s4 ,geol4 ,surv47 ,flood-pla9s due to ob/ructions4--,aga91 any ob/acle 9 a /ream's c\rse is likely to cause deposition above4 ,?us dams built across riv]s entail ! deposition ( s$im5t above4 ,:]e a /ream fl[s ov] ! outcropp+ edges ( /rata ( diff]5t /r5g?1 ! m resi/ant s]ve1 9 "s s5se1 z dams4 ,above !m ! /ream cuts its b$ to a l[ gradi5t1 &1 becom+ sluggi%1 drops m or less ( ! detritus br\ght d[n f above4 ,ob/acles ( any sort across a /ream's *annel1 !re=e1 favor ! developm5t ( alluvial pla9s4 ,illu/ration3 ,fig4 #agh4--,! levees ( ! ,mississippi 9 cross-section1 #d miles nor? ( ,donaldsonville1 ,la4 ,v]tical scale #ej4 ,! horizontal l9e 9 ! diagram repres5ts sea-level4 ,! bottom ( ! *annel at ?is po9t is f> bel[ sea-level4 ,levees4--,z ! /ream 9 flood escapes its *annel & ov]spreads its pla91 its imm$iate banks are ! site ( active deposition1 = x is "h t ! velocity ( ! ov]fl[+ wat] is fir/ notably *eck$4 ,on ! banks ( ! *annel1 !re=e1 l[ alluvial ridges1 call$ natural levees1 are built up 7,fig4 #agh1 & ,pl4 ,,xv74 ,!y may be n>r[1 or hundr$s ( feet 9 wid?1 & are (t5 sev]al feet above ! pla9s beh9d !m1 giv+ ! latt] a slope away f ! *annel ( ! /ream4 ,!y are sometimes high en\gh to control ! c\rses ( tribut>y /reams1 z %[n by num]\s tribut>ies to ! ,mississippi bel[ ! ,ohio4 ,! ,yazoo1 = example1 fl[s "s #bjj miles on ! flood-pla9 ( ! ,mississippi be=e x jo9s t riv] ne> ,vicksburg4 ,! levees ev5 become divides1 direct+ dra9age away f ! /reams !y gu>d 7,pl4 ,,xv74 ,/reams sometimes build levees fa/] ?an _! tribut>ies aggrade _! *annels4 ,! latt] are !n pond$1 giv+ rise to lakes4 ,! lakes on ! l[] c\rses ( ! tribut>ies to ! ,r$ ,riv] ( ,l\isiana are examples4#gj ,!y are sometimes built up above _! natural level & kept 9 repair by human ag5cy s z to conf9e ! /reams 9 "t ( flood4 ,?is is a s\rce ( dang] unless !y be /eadily ma9ta9$1 = ! break+ ( su* levees (t5 occasions great de/ruction4 ,a case 9 po9t is ! break+ ( ! levees ( ! ,mississippi ne> ,new ,orleans 9 #ahij4 ,! wat] broke ?r\gh ! levees at ! ,nita & ,m>t9ez crevasses 7,fig4 #ahg7 & fl[$ ea/w>d 7f ! =m]7 ) a curr5t ( #ae miles p] h\r1 spread+ de/ruction 9 its pa?4 ,! wat] fl[$ ea/w>d ?r\gh ,lakes ,pont*>tra9 & ,borgne1 & ent]$ ,mobile ,bay ) su* volume1 velocity1 & load ( mud1 z to de/roy = a "t ! oy/] & fi% indu/ries ( t locality4#ga ,illu/ration3 ,,plate ,,xv4 ,,ne> ,,hahnville1 ,,l\isiana4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xvi4 ,fig4 #a4 ,,miss\ri4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,miss\ri4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #c4 ,,miss\ri4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #agi4--;,flood-pla9 ( ! ,mississippi ,riv] s\? ( ! m\? ( ! ,ohio4 7,f *>ts ( ! ,miss4 ,riv4 ,commission47 ,illu/ration3 ,fig4 #ahj4--;,diagram illu/rat+ an e>ly /age 9 ! developm5t ( me&]s4 ,! %ad$ "p repres5ts ! area ov] :i* ! /ream has work$4 ,flood-pla9 me&]s4 ,cut-&-fill4--,a /ream ) an alluvial pla9 is likely to me&] widely 7,pl4 ,,xvi74 ,9 g5]al t]ms ?is may be said to be ! result ( l[ velocity1 :i* all[s x to be easily turn$ aside4 ,7 ! c\rse ( su* a /ream made /raight1 x w\ld soon become crook$ aga94 ,! mann] ( *ange is illu/rat$ by ,figs4 #ahj & #aha4 ,if ! banks be less resi/ant at "s po9ts ?an at o!rs1 z is always ! case1 ! /ream w cut 9 at ^? po9ts4 ,if ! configuration ( ! *annel is su* z to direct a curr5t aga9/ a giv5 po9t1 a 7,fig4 #ahj71 ! result is ! same1 ev5 )\t inequality ( mat]ial4 ,once a curve 9 ! bank is />t$1 x is increas$ by ! curr5t :i* is direct$ into x4 ,fur!rmore1 z ! curr5t issues f ! curve1 x imp+es aga9/ ! opposite bank & develops a curve at t po9t4 ,! wat] issu+ f ?is curve develops ano!r1 & s on4 ,once />t$1 ! curves or me&]s t5d to become m & m pron\nc$ 7comp>e ,figs4 #ahj & #aha74 ,9 ! case repres5t$ by ,fig4 #a1 ,plate ,,xvi 7,miss\ri ,riv] ne> ,brunswick1 ,mo47 ! n>r[ neck ( l& betwe5 curves is almo/ cut ?r\gh4 ,:5 ?is is accompli%$1 ! /ream w ab&on its wide curve4 ,a lat] /age 9 ! process is %[n 9 ,fig4 #b1 ,plate ,,xvi 7! ,osage ,riv] ne> ,s*ell1 ,mo474 ,! /raight5+ ( ! *annel is (t5 accompli%$ 9 ano!r way4 ,ev5 be=e ! me&]s rea* ! /age repres5t$ by ,fig4 #a1 ,plate ,,xvi1 ! position ( ! *annel becomes un/able4 ,9 "t ( flood1 ! :ole flat is cov]$ ) fl[+ wat]4 ,! great] dep? ( wat] 9 ! *annel t5ds to give x a velocity great] ?an t ( ! wat] on ! flat outside4 ,b ! di/ance f a to c via b 7,fig4 #aha7 is mu* great] ?an t 9 a direct l9e4 ,x foll[s t ! slope f a to c direct is great] ?an t by way ( b4 ,if ! curr5t betwe5 a & c 9 "t ( flood be /rong en\gh to erode1 x may deep5 its b$1 & !reby increase ! volume ( wat] foll[+ ?is c\rse4 ,! increas$ volume gives increas$ velocity1 & ! result may be ! op5+ ( a *annel betwe5 a & c direct4 ,! *annel may be worn s deep t :5 ! flood subsides1 ! /ream w foll[ x4 ,s long z ! ab&on$ *annel-curve rema9s unfill$ ) s$im5t1 x is (t5 call$ a cut-(f4 ,if x conta9s /&+ wat] & has ! prop] =m1 x is call$ an ox-b[ lake 7,fig4 #ahb71 or sometimes a bay\4 ,! wat]-fill$ portions are n always b[s 7,fig4 #ahc1 ,osage ,riv]1 ne> ,butl]1 ,mo474 ,cut-(fs1 ) or )\t /&+ wat]1 are ( common occurr5ce along mo/ riv]s ) wide pla9s4 ,me&]+ is n conf9$ to /reams :i* are ne> sea-level4 ,ev5 small creeks at high altitudes may me&]1 if s situat$ z to h slight velocity4 ,tr\t ,creek 9 ! ,yell[/one ,p>k 7,fig4 #ahd7 is an example4 ,illu/ration3 ,fig4 #aha4--;,diagram illu/rat+ lat] /ages 9 ! developm5t ( me&]s4 ,illu/ration3 ,fig4 #ahb4--,me&]s & cut-(fs 7ox-b[ lakes7 9 ! ,mississippi ,valley a little bel[ ,vicksburg4 ,! figure also %[s ! migration ( me&]s d[n-/ream1 & _! t5d5cy to increase !mselves4 7,f *>ts ,nos4 #ah & #ai1 ,mississippi ,riv] ,commission47 ,illu/ration3 ,fig4 #ahc4--;,bay\ ,lakes1 ,osage ,riv]1 ne> ,butl]1 ,mo4 ,!re seems to be "s relation betwe5 ! wid? ( ! belt )9 :i* a /ream me&]s1 & ! wid? ( ! /ream itself4 ,rec5tly x has be5 e/imat$ t ! ratio betwe5 !m is #ah 3 #a4gb ,dur+ ! developm5t ( ! me&]s x is to be not$ t lat]al planation on ! "o side ( a /ream is accompani$ by deposition on ! o!r4 ,?is is cut-&-fill4 ,! s$im5t erod$ f ! curve :i* is concave t[>d ! /ream is %ift$ d[n-/ream1 :ile t deposit$ 9 ! curve :i* is convex t[>d ! /ream is br\ght d[n f above4 ,?us ev5 9 ! developm5t ( me&]s1 ! mat]ial :i* is dislodg$ is %ift$ d[n-/ream4 ,s9ce ! curr5t direct$ aga9/ ! d[n-/ream side ( a gr[+ me&] is on ! av]age /rong] ?an t direct$ aga9/ ! opposite side1 ! me&] itself has a t5d5cy to migrate d[n-/ream 7,fig4 #ahb74 ,9 _! evolution1 ! curves ( a /ream's *annel (t5 rea* & und]m9e ! valley bluff 7,pl4 ,,vii74 ,s9ce ! me&]s are1 on ! av]age1 %ift$ d[n-/ream individually1 & s9ce me&]s are frequ5tly develop$ 9 new places1 x foll[s t a me&]+ /ream t5ds to wid5 its valley ?r\gh\t4 ,wid5+ is also effect$ 9 o!r ways1 = a /ream ) a flood-pla9 sometimes ab&ons its *annel altoge!r = miles at a /ret*1 & ! new c\rse *os5 may be aga9/ "o ( ! bluffs ( ! valley4 ,su* *anges are mo/ likely to take place :]e deposition along *annel & levees has br\ght ! "p ( ! flood-pla9 7?\gh n necess>ily ! bottom ( ! *annel7 adjac5t to ! /ream above ! level ( t f>!r f x 7,fig4 #agh74 ,! *ange is likely to be effect$ 9 "t ( flood4 ,flood-pla9s (t5 atta9 great size4 ,t ( ! ,mississippi bel[ ! ,ohio 7,fig4 #agi7 has a wid? rang+ f r m ?an #bj miles at ,hel5a 7,ark471 to some?+ l #hj miles 9 ! latitude ( ,gre5ville 7,miss474#gc ,bel[ ! ,ohio its area is some?+ l #cj1jjj squ>e miles1 & its entire area has be5 e/imat$ at ab\t #ej1jjj squ>e miles4#gd ,!oretically1 ! rotation ( ! e>? %\ld affect ! erosion ( /reams1 increas+ x on ! "o bank 7! "r 9 ! nor!rn hemisph]e & ! left 9 ! s\!rn7 & decreas+ x on ! o!r4#ge ,! /reams d\btless accommodate !mselves to ! rotation ( ! e>? 9 ! orig9al developm5t ( _! gradation-pla9s & flood-pla9s1 & ! lat] effects ( rotation are usually inconspicu\s4 ,illu/ration3 ,fig4 #ahd4--,me&]s ( ,tr\t ,creek1 ,yell[/one ,p>k4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,sc\r-&-fill4--,x has already be5 %[n t aggrad+ /reams cut lat]ally at ! same "t t !y build up _! pla9s4 ,x is n[ to be add$ t !y p]iodically deep5 _! *annels to a notable ext5t1 & t ! deep5+ ( ! *annel takes place at ! v "t :5 ! flood-pla9 is be+ aggrad$4 ,9 o!r words1 ! /ream 9 flood aggrades its pla91 & degrades its *annel4 ,?is foll[s f ! fact t ! curr5t is sluggi% 9 ! =m] position1 :]e ! wat] is %all[1 & rapid 9 ! latt]1 :]e x is deep4 ,:5 ! flood subsides1 ! *annel1 deep5$ :ile ! curr5t 0 torr5tial1 is fill$ aga9 by ! feebl] curr5t :i* foll[s4 ,?is alt]nate deep5+ & fill+ is kn[n z sc\r-&-fill4 ,x is well illu/rat$ by ! ,miss\ri ,riv]4 ,at ,nebraska ,city1 sc\r is believ$ to occasionally rea* dep?s ( #gj to #ij feet4#gf ,at ,blair1 ab\t #be miles above ,omaha1 ! same riv] is believ$ to cut to b$-rock 7ab\t #dj feet bel[ ! bottom ( ! *annel 9 l[ wat]7 twice a ye>1 t is1 dur+ floods4#gg ,fig4 #ahe %[s ! *anges record$ 9 ! *annel ( ! riv] at ?is po9t dur+ ! ye> #ahhc4 ,x %[s t ! sc\r-&-fill dur+ ?is ye> am\nt$ to almo/ #dj feet4 ,all /reams simil>ly situat$ d a l "w4 ,! mat]ial ?us erod$ is %ift$ d[n-/ream1 "s ( x = %ort di/ances only1 & "s ( x to ! sea4 ,ev5 an aggrad+ /ream !re=e is n )\t erosive activity2 x is a /ream ^: fill exce$s its sc\r1 n "o :i* has ceas$ to erode4 ,illu/ration3 ,fig4 #ahe4--;,diagram illu/rat+ sc\r & fill 9 ! ,miss\ri ,riv]4 ,a record ( s\nd+s at ,blair ,bridge 7ne> ,omaha71 #ahhc4 ,%[s also ! cross-sections ( ! riv] at v>i\s rates4 7,todd1 ,bull4 #aeh1 ,u4 ,s4 ,geol4 ,surv47 ,mat]ials ( ! flood-pla94--,z a result ( its v>y+ velocities 9 flood & l[ wat]1 a /ream may deposit co>se mat]ial at "o "t & f9e at ano!r4 ,a simil> sequ5ce ( deposits takes place 9 ! flood-pla9 ( a me&]+ /ream1 irrespective ( floods4 ,flood-pla9 deposits are (t5 !re=e v het]og5e\s1 z %[n 9 ,fig4 #ahf1 :i* repres5ts ! con/itution ( ! alluvium ( ! ,miss\ri ,riv] at ,omaha4 ,! deposits ( ! /reams range f ! f9e/ clay1 ?r\gh s& to gravel1 & ev5 b[ld]s4 ,9 g5]al !y become f9] d[n-/ream4 ,9 a giv5 pla91 !y are usually co>s] bel[ & f9] above4 ,illu/ration3 ,fig4 #ahf4--;,diagram to %[ ! het]og5e\s "* ( alluvial deposits4 7,todd1 ,bull4 #aeh1 ,u4 ,s4 ,geol4 ,surv47 ,topography ( ! flood-pla94--,! flood-pla9 is ne>ly1 b n altoge!r1 flat4 ,x has a g5tle slope d[n-/ream1 & (t5 = a di/ance f ! sides t[>d ! c5t] 7,fig4 #agd74 ,?is latt] slope is ! result ( deposition by wat]s desc5d+ to ! pla9 f ! sides4 ,x is de/roy$ :]ev] a me&]+ /ream rea*es its bluffs4 ,:5 levees are well develop$1 !re is a slope f !m t[>d ! sides ( ! valley 7,fig4 #agh71 b x r>ely cont9ues to ! limit+ bluffs4 ,s9ce a /ream ) a well-develop$ flat frequ5tly %ifts its c\rse1 old levees & ab&on$ *annels l5d v>iety to ! topography ( ! flood-pla94 ,! topographic adju/m5t ( tribut>ies4#gh--,! me&]+ & %ift+ ( a ma9 /ream affects its tribut>ies4 ,if a ma9 /ream sw+s aga9/ ! bluff ?r\gh :i* a tribut>y ent]s1 ! latt] br+s its *annel into topographic adju/m5t by l[]+ its end to ! level ( ! ma94 ,if n[ ! ma9 /ream opposite ! tribut>y sw+s to ! o!r side ( its valley1 ! tribut>y mu/ make its way across ! flat ) a v l[ gradi5t4 ,n only ?is1 b ! flat ( ! ma9 valley ?r\gh :i* ! tribut>y mu/ fl[ is likely to be aggrad$ by ! ma9 9 "t ( flood4 ,! result is t ! tribut>y /ream becomes an aggrad+ /ream at its deb\*ure1 & topographic adju/m5t is n e/abli%$ until x has fill$ up ! l[] end ( its valley to "s notable ext5t4 ,! fill+ ( ! l[] end ( ! tribut>y likewise affects ! l[] ends ( its l[] tribut>ies4 ,illu/ration3 ,fig4 #ahg4--;,a g5]al view ( ! ,mississippi delta4 ,if ! ma9 /ream aga9 sw+s ov] to ! po9t :]e ! tribut>y issues f its valley1 ! tribut>y /ream & all its affect$ tribut>ies aga9 become erod+ /reams4 ,?us sc\r-&-fill are n conf9$ to ! valley ( ! ma9 /ream4 ,riv]-lakes4--,:ile riv]s are 9 g5]al ho/ile to lakes1 !y sometimes give orig9 to !m4 ,oxb[ lakes 7,fig4 #ahb & ,pl4 ,,xvi71 due to ! cut-(fs ( me&]+ /reams1 h already be5 ref]r$ to4 ,lakes =m$ 9 ! same way h o!r =ms 7,pl4 ,,xvi & ,fig4 #ahc74 ,riv]s also give rise to lakes ?r\gh ! deposits !y make4 ,if a ma9 /ream ob/ructs its tribut>ies by deposition at _! deb\*ures1 _! l[] c\rses are pond$ & conv]t$ into lakes4 ,! lakes along ! tribut>ies to ! ,r$ ,riv] ( ,l\isiana h already be5 cit$ z examples4 ,if a tribut>y br+s m load to its ma9 ?an ! latt] c c>ry away1 ! detritus con/itutes a p>tial dam1 pond+ ! riv] & caus+ x to exp& into a lake above4 ,su* is ! orig9 ( ,lake ,pep9 already ref]r$ to4 ,9 m\nta9 regions1 ! alluvial cones ( tribut>y valleys sometimes pond _! ma9s4 ,illu/ration3 ,fig4 #ahh4--,longitud9al section ( an incipi5t delta made ( co>se mat]ial4 ,riv]s may be damm$ 9 o!r ways1 z by lava fl[s1 by l&slides1 by glacial drift1 etc4 ,9 all su* cases1 lakes may come into exi/5ce1 b !y are n due prim>ily to ! activity ( ! riv] itself4 ,deltas4#gi--,:]e a /ream ent]s /&+ wat]1 or a sl[] /ream1 a special =m ( pla91 ! delta1 is sometimes built up 7,figs4 #afi1 #ahg1 & #ahh74 ,deltas & alluvial fans h mu* 9 common1 & _! only notable diff]5ces are ^? impos$ by ! diff]5ces 9 ! conditions ( deposition4 ,! curr5t ( ! /ream is *eck$1 b n altoge!r /opp$1 at its imm$iate deb\*ure4 ,if x c>ries abundant s$im5t1 mu* ( x w be promptly dropp$ :]e ! decrease 9 velocity is fir/ felt4 ,su* fl[ z !re is beyond ! deb\*ure is n conf9$ to a def9ite *annel1 & ! deposits made are !re=e spread m or less on ei!r side ( ! l9e :i* repres5ts ! cont9uation ( ! /ream's c\rse4 ,z ! dep? ( ! wat] into :i* ! /ream fl[s increases1 ! curr5t dim9i%es4 ,out to ! po9t :]e ! dep? ( ! /&+ wat] is less ?an ! dep? ( ! curr5t1 ! latt] affects ! bottom1 & ! surface ( ! deposits made slopes g5tly seaw>d2 b :]e ! dep? ( ! /&+ wat] is su* t ! project$ /ream curr5t is ineffective at ! bottom1 all ! load roll$ along ! bottom is dropp$1 & a depositional slope is e/abli%$ 7,fig4 #ahh71 its upp] edge be+ bel[ sea-level by an am\nt correspond+ r\ghly to ! dep? ( ! curr5t :i* br+s ! detritus4 ,! out] slope is relatively /eep & well-def9$ :]e ! detritus is co>se1 & relatively g5tle & ill-def9$ :]e x is f9e4 ,?us ! /ream t5ds to con/ruct a sort ( plat=m 9 ! wat] j beyond its deb\*ure4 ,! successive deposits on ! out] abrupt slope w dip con=mably ) its surface 7,fig4 #ahi74 ,! f9e/ s$im5t w be c>ri$ beyond ! /eep slope1 & con=m to ! topography ( ! bottom beyond 7c1 ,fig4 #ahi74 ,at ! beg9n+1 ! top ( ! delta plat=m is at ! level ( ! bottom ( ! /ream's *annel at ! po9t ( deb\*ure1 b x is gradually aggrad$ z wat] cont9ues to fl[ ov] x4 ,its l&w>d m>g9 is pres5tly built up to sea-level & !n above x1 & z ! delta gr[s ! delta-l& is ext5d$ seaw>d 7comp>e ,figs4 #ahh & #ahi74 ,at ! same "t ! *annel ( ! /ream above ! orig9al head ( ! delta is aggrad$1 = ! curr5t !re is *eck$ by ! aggradation ( ! delta4 ,?us alluvial deposits cont9u\s ) ! delta are ext5d$ l&w>d4 ,illu/ration3 ,fig4 #ahi4--,longitud9al section ( ! delta at a lat] /age ( developm5t4 ,! projection ( ! direction ( ! l[] end ( ! /ream may be said to be ! axis ( ! extra-deb\*ure curr5t4 ,f ?is axis1 :]e ! fl[ is /ronge/1 ! movem5t div]ges m or less to "r & left4 ,s9ce ! velocity ( ! div]g+ wat] is r$uc$ m rapidly ?an t ( ! wat] :i* foll[s ! axis ( fl[1 deposition is likely to take place fa/] on ei!r side ( ! axis ?an along ! axis itself4 ,! result is t ! extra-deb\*ure curr5t t5ds to build up levee-l ridges on ei!r side1 mak+ a sort ( sluice-way = itself4 ,?is sluice-way is gradually ext5d$ seaw>d1 & at ! same "t gradually fill$4 ,z its capacity is r$uc$1 m & m ( ! wat] fl[s ov] its sides4 ,pres5tly ! escape ( ! wat] ov] ! little side-levees w develop a break at "s po9t1 & a l9e ( di/9ct fl[ !n div]ges f ! ma9 curr5t4 ,?is di/ribut>y repeats ! hi/ory ( its ma94 ,?us ! processes ( levee-build+1 *annel-fill+1 & levee-break+ foll[ "o ano!r1 until "s su* sy/em ( curr5ts z %[n 9 ,fig4 #aij is develop$4 ,! result is t a delta's gr[? is n simply 9 ! l9e ( ext5sion ( ! ma9 /ream1 b 9 a m or less semicircul> area1 ! c5t] ( ! circle be+ a po9t slightly bel[ ! position ( ! deb\*ure ( ! /ream :5 ! delta began4 ,at any /age 9 its developm5t ! m>g9 ( ! delta is m or less cr5ate 7,fig4 #aia71 or *>act]iz$ by delta f+]s 7,fig4 #aij71 ! projections correspond+ to ! positions ( ! deb\*ures ( ! late/ /reams fl[+ across x4 ,! extreme ends ( ! delta lobes 7,fig4 #aij71 & ( gr\ps ( ! delta f+]s1 (t5 h some?+ ( ! %ape ( ! ,greek lett] f :i* ! "n orig9at$1 b ! resemblance 9 =m betwe5 a well-develop$ delta & ! ,greek lett] is n /rik+4 ,deltas are sometimes built 9 bays1 & 9 su* cases _! =ms are pr$et]m9$ on all sides b "o4 ,! head ( a delta is sometimes arbitr>ily locat$ at ! po9t :]e ! fir/ di/ribut>ies are giv5 (f4 ,s9ce ?is po9t %ifts widely ) "t1 ! def9ition c h>dly be accept$4 ,on ?is basis ! head ( ! ,mississippi delta is ab\t #bjj miles above its l[] end4 ,9 reality x is mu* f>!r nor?4 ,illu/ration3 ,fig4 #aij4--,! t]m9us ( ! delta ( ! ,mississippi4 7,c4 & ,g4 ,survey47 ,illu/ration3 ,fig4 #aia4--;,a m9iature delta4 ,! /ructure ( a delta1 %[n 9 ,fig4 #ahi1 %[s its hi/ory4 ,at any /age 9 its gr[? ! riv] dis*>ges its s$im5t across t "p ( ! plat=m already built4 ,! s$im5t roll$ at ! bottom ( ! curr5t is dump$ on rea*+ ! /eep slope1 & con/itutes ! incl9$ =e-set b$s %[n 9 ,fig4 #ahi4 ,! mat]ial 9 susp5sion is c>ri$ f>!r1 settles m gradually1 & con/itutes ! bottom-set b$s 7c1 ,fig4 #ahi74 ,9 "t ! bottom-set b$s1 orig9ally deposit$ "s di/ance beyond ! deb\*ure1 may come to be ov]la9 by ! =e-set b$s1 deposit$ at a lat] "t4 ,:ile ! =e-set b$s are be+ deposit$ on ! /eep slopes ( ! delta1 & ! bottom-set b$s beyond1 deposition is also tak+ place on ! top ( ! delta4 ,^! top-set b$s are laid d[n 9 a ne>ly horizontal position1 & _! seaw>d m>g9 is gradually ext5d$4 ,?us ! delta comes to h ! ?reefold /ructure %[n 9 ,fig4 #ahi4 ,t "p ( ! delta :i* is above ! abrupt slope ( its front corresponds 9 all ess5tials to an alluvial fan2 b ! delta z a :ole diff]s f ! fan 9 its abrupt & cr5ate or digitate m>g94 ,x is to be not$ t ! delta is n :olly ! product ( a /ream's activity4 ,! /ream supplies ! mat]ial1 b ! lake or sea r5d]s at lea/ passive assi/ance 9 its disposition4 ,n all riv]s op5+ into ! sea build deltas1 & _! failure is (t5 ! result ( waves or %ore curr5ts :i* c>ry (f ! riv] s$im5t4 ,deltas are1 h[ev]1 sometimes =m$ 9 tidal seas1 z at ! deb\*ures ( ! ,yukon2 ! ,mack5zie1 :]e ! tidal range is ?ree feet2 ! ,nig]1 :]e ! range is f\r feet2 ! ,hoang-,ho1 :]e ! range is eight feet2 & ! ,brahmaputra & ,ganges1 :]e ! range is sixte5 feet4#hj ,s9ce lakes1 bays1 gulfs1 & inl& seas h weak] waves & curr5ts ?an ! op5 sea1 !y are m favorable ?an ! latt] = ! gr[? ( deltas4 ,h5ce occur su* deltas z ^? ( ! ,mississippi1 ! ,nile1 ! ,po1 & ! ,danube4 ,deltas are likely to be abs5t1 or conf9$ to ! heads ( bays1 on coa/s :i* h rec5tly sunk4 ,_! g5]al abs5ce on ! ,atlantic coa/ ( ! ,unit$ ,/ates is a case 9 po9t4 ,! foll[+ figures give "s idea ( ! ext5t ( deltas1 & ( _! importance 9 l& build+4 ,! ,mississippi delta is advanc+ into ! ,gulf at ! rate ( ab\t #ajj y>ds p] ye>1 or a mile 9 #af or #ag ye>s4 ,its l5g? is m ?an #bjj miles1 its area m ?an #ab1jjj squ>e miles1 & its dep? at ,new ,orleans has be5 e/imat$ at #gjjha to #ajjjhb feet4 ,?is great dep? is believ$ to be ! result ( subsid5ce1 & s ( ! sup]position ( "o delta on ano!r4#hc ,! delta ( ! ,yukon has a sea m>g9 ( #gj miles1 & ext5ds m ?an #ajj miles inl&4 ,! delta ( ! ,rhne has also _h a rem>kable gr[?1 consid]+ ! size & ! hi/ory ( ! /ream4 ,arles1 ne> ! deb\*ure ( ! /ream1 0 #ad to #af miles inl& 9 ! f\r? c5tury ,b4,c41 & is n[ #cj miles inl&4#hd ,! ,rhne has also built a great delta 9 ,lake ,g5eva1 & its l[] delta is built ( s$im5t ga!r$ bel[ ! lake4 ,! ,po has built a delta #ad miles beyond ,adria1 ! port :i* gave its "n to ! ,adriatic ,sea4 ,! ext5sion ( ?is delta has be5 at ! av]age rate ( ab\t #ej feet p] ye>1 b rec5tly1 on acc\nt ( artificial embankm5ts1 ! rate has be5 mu* m rapid4#he ,! ,ganges & ,brahmaputra toge!r h made a delta ( great size4 ,its area is sometimes e/imat$ to be z high z #ej1jjj or #fj1jjj squ>e miles1 & its head is m ?an #bjj miles f ! sea4#hf ,! head ( ! ,nile delta is #ij miles f ! sea1 & x has a coa/al bord] ( #ahj miles4 ,! head ( ! delta ( ! ,hoang-,ho is ab\t #cjj miles f ! coa/1 & its seaw>d bord] has a l5g? ( ab\t #djj miles1 ?\gh ) "s highl& int]ruptions4#hg ,aft] a delta has be5 built into a lake1 ! lake may disappe>1 leav+ ! delta out ( wat]4 ,su* 8fossil0 deltas1 if s rec5tly expos$ t erosion has n de/roy$ _! di/9ctive features1 are readily recogniz$ by _! flat tops1 _! abrupt & lobate fronts1 & _! *>act]i/ic /ructure4 ,!y are (t5 a means ( det]m9+ ! =m] exi/5ce ( ext9ct lakes1#hh or ! =m] high] levels ( lakes :i* /ill exi/4#hi ,elevat$ deltas on sea%ores %[ ei!r a rise ( ! l& or a depression ( ! sea-level4 ,! mat]ial :i* is c>ri$ along ! coa/s or %ores f ! m\?s ( riv]s may take on v>i\s & peculi> =ms1 accord+ to ! /r5g?1 direction1 & relations ( waves & curr5ts4 ,! consid]ation ( ^! =ms belongs m prop]ly to ! "w ( ! sea ?an to t ( riv]s1 s9ce riv]s are n conc]n$ 9 _! con/ruction except 9 supply+ mat]ial4 ,delta lakes4--,delta-build+ /reams sometimes help to =m lakes by ?r[+ _! deposits ar\nd an area :i* fails to be aggrad$ to sea-level4 ,lake ,pont*>tra91 & o!r lakes 9 ! delta ( ! ,mississippi are examples 7,fig4 #ahg74 ,illu/ration3 ,fig4 #aib4--,t]races ( ! ,frazi] ,riv] at ,lillooet1 ,b4 ,c4 7,calv947 ,,/ream ,,t]races4 ,/ream t]races#ij are b5*-l flats or n>r[ pla9s along ! sides ( valleys 7,fig4 #aib74 ,!y are usually n>r[1 b sometimes h great l5g? 9 ! direction ( ! axis ( ! valley4 ,!y orig9ate 9 v>i\s ways4 ,due to inequalities ( h>dness4--,ref]5ce has already be5 made 7p4 #adj7 to ! effect ( h>d horizontal lay]s 9 ! developm5t ( t]races & t]raci=m projections on ! sides ( valleys 7,fig4 #abj74 ,su* t]races are ! result ( diff]5tial degradation1 & ! upp] surface ( ! h>d lay] m>ks ! l[] limit ( ! t]race1 :i* commonly has a di/9ct slope t[>d ! /ream4 ,except :]e int]rupt$ by tribut>y valleys1 su* t]races are likely to be cont9u\s 9 a valley s long z ! /ructure rema9s ! same & ! /ream su/a9s ! same relation to x4 ,su* t]races w\ld fir/ %[ !mselves 9 ! old] "p ( ! valley4 ,! effect ( incl9ation ( ! h>d /ratum on ! developm5t ( su* t]races w be readily inf]r$4 ,t]races & b5*es ( ?is sort are n equally di/9ct at all /ages ( a valley's hi/ory4 ,= great di/9ctness1 ! h>d lay] %\ld h be5 expos$ long en\gh to all[ ! g5]al processes ( erosion to h effect$ consid]able diff]5tial we>1 b n long en\gh to all[ ! topographic effects ( unequal resi/ance to be oblit]at$4 ,illu/ration3 ,fig4 #aic4--;,diagram illu/rat+ a di/9ct t]race & a 8second bottom 7b710 :i* may be reg>d$ z a l[ t]race4 ,normal flood-pla9 t]races4--,x has be5 se5 t deposition 9 a riv] valley /&s 9 m or less def9ite relation%ip to ! /age ( its developm5t1 & t ! deposition :i* leads to ! developm5t ( an alluvial pla9 is likely to take place :]e ! high] gradi5t ( ! upp] c\rse gives place to ! g5tl] gradi5t ( ! l[]4 ,x has also be5 se5 t z a /ream's hi/ory advances1 ! /ret* :]e ! gradi5t is high rec$es up-/ream1 & t ! po9t :i* m>ks ! head ( active deposition foll[s4 ,x foll[s t a riv] flat or flood-pla9 normally beg9s 9 ! l[] "p ( a valley1 & works progressively headw>d1 its upp] end foll[+1 at "s consid]able di/ance1 ! head ( ! valley itself4 ,! common] riv] t]races are remnants ( =m] flood-pla9s1 bel[ :i* ! /reams :i* made !m h cut _! *annels4 ,x has already be5 po9t$ out 7p4 #ahd7 t processes ( erosion & deposition "w toge!r 9 ! developm5t ( flood-pla9s1 & t "s flood-pla9s h b little alluvium 7,fig4 #agd71 :ile o!rs owe _! orig9 :olly to /ream deposits 7,fig4 #age74 ,x foll[s t t]races develop$ f flood-pla9s may be ( rock1 ( alluvium1 or ( rock cov]$ ) alluvium4 ,! am\nt :i* a riv] *annel mu/ be deep5$ 9 ord] to *ange ! remnants ( its flood-pla9 to t]races _c be def9itely /at$4 ,:5 a *annel is s deep t ! remnants ( a =m] flood-pla9 are no long] flood$1 !y w\ld be call$ t]races1 especially if a l[] flood-pla9 has be5 develop$4 ,ev5 ?\gh n above ! rea* ( floods1 !y are (t5 call$ t]races if !y are notably above ! *annel & sep>at$ f x by a l[] pla94 ,?us ! flat at b1 ,fig4 #aic1 w\ld be call$ a t]race1 ev5 ?\gh cov]$ by wat] 9 exceptional floods2 b ! flat at c1 b slightly above ! *annel1 w\ld h>dly be call$ a t]race4 ,illu/ration3 ,fig4 #aid4--;,diagram illu/rat+ ! beg9n+ ( ! developm5t ( a t]race f a flood-pla94 ,! "q n[ arises :y a /ream1 hav+ once develop$ a flood-pla91 %\ld s9k its *annel to a l[] level1 leav+ p>ts ( ! old flood-pla9 z t]races4 ,?is may be br\ght ab\t by ! op]ation ( v>i\s causes4 7#a7 ,9 ! fir/ place1 ! head ( ! valley-pla9 :]e ! fir/ notable deposition takes place normally advances up-/ream4 ,aft] ! advance has be5 consid]able1 ! desc5d+ /ream may1 on rea*+ ! head ( its valley-pla91 lose s mu* ( its load z to be able to s9k its *annel into ! flood-pla9 f>!r d[n ! valley 7,fig4 #aid74 7#b7 ,ord9>ily a /ream does n drop all its load at ! head ( its pla91 b only its excess2 b x w always drop co>se s$im5t to take f9e1 if f9e be available4 ,= a relatively small am\nt ( co>se mat]ial dropp$1 a relatively l>ge am\nt ( f9e may be tak5 up 7p4 #agi74 ,o!r ?+s be+ equal1 x foll[s t :5 a /ream drops co>se mat]ial to take f9e1 its *annel is degrad$ unless !re is at ! same "t a great r$uction 9 ! /ream's en]gy4 ,su* r$uction is likely to g ) ! decreas+ declivity d[n-/ream2 b ?is is p>tly1 or sometimes :olly1 c\nt]balanc$ by ! increas+ volume ( wat]4 ,by ! ex*ange ( load1 !re=e1 a /ream may ultimately s9k its *annel bel[ ! flood-pla9 :i* ! e>li] & p]haps small] /ream _h develop$4 ,illu/ration3 ,fig4 #aie4--;,diagram to illu/rate ! developm5t ( riv] t]races by ! wid5+ ( a *annel or me&] belt4 ,! valley flat above might n be call$ a t]race2 b ! same pla9 bel[1 :]e ! me&] belt has "s wid?1 w\ld be call$ a t]race4 7#c7 ,aga91 s long z a /ream is actively erod+ at its head1 !re is likely to be "s aggradation bel[4 ,at a lat] /age 9 ! /ream's hi/ory1 :5 active erosion at ! head has ceas$ because ( ! r$uction ( ! surface1 less mat]ial w be c>ri$ f ! upp] "p ( ! valley1 & ! /ream on ! flood-pla9 bel[1 =m]ly load$ ) mat]ial f up ! valley1 is n[ free to take up & c>ry away mat]ial tempor>ily left on ! flood-pla94 ,! result is a deep5+ ( ! *annel4 7#d7 ,any /ream :i* has rea*$ ! flood-pla9 /age is likely to me&]4 ,aft] ! flood-pla9 has become wide1 ! wid? ( ! belt )9 :i* ! /ream me&]s is less ?an ! wid? ( its pla94 ,9 ! ,l[] ,mississippi1 = example1 ! me&] belt is (t5 no m ?an a ?ird to a t5? ( ! wid? ( ! flood-pla94 ,x has already be5 po9t$ out t ! me&]s migrate d[n ! valley4 ,9 s do+ !y depress ! me&] belt1 ! t5d5cy be+ to r$uce x to ! level ( ! *annel1 &1 !re=e1 bel[ ! level ( ! flood-pla94 ,z ! me&] belt wid5s1 ! depression :i* x develops becomes m & m capaci\s4 ,pres5tly x may atta9 su* dim5sions z to hold ! wat] ( ord9>y floods4 ,at ?is /age1 or ev5 be=e1 su* p>ts ( ! e>li] flood-pla9 z rema91 are t]races4 ,^! sev]al t5d5cies conspire to p>tially de/roy riv] flood-pla9s1 & to trans=m su* p>ts z rema9 into t]races 9 ! normal c\rse ( a riv]'s hi/ory4 ,!y appe> fir/ 9 ! l[] "p ( ! valley1 & migrate headw>d1 foll[+ ! c\rse ( ne>ly e o!r phase ( activity 9 a /ream's hi/ory4 ,! heads ( ! t]races foll[1 at a respectful di/ance1 ! head ( ! flood-pla91 j z ! head ( ! flood-pla9 foll[s at a di/ance ! head ( ! valley4 ,! second & subsequ5t flood-pla9s & ! t]races to :i* !y give orig9 foll[ ! same c\rse4 ,t]races develop$ by ! normal activities ( a /ream are always l[1 & x is improbable t !y w\ld ord9>ily be conspicu\s4 ,! v]tical di/ance betwe5 ! fir/ 7highe/7 & second is great] ?an t betwe5 ! second & ?ird4 ,! pr9ciples develop$ on page #fe et seq41 9 connection ) ! erosion ( ! hypo!tical isl&1 are applicable "h4 ,flood-pla9 t]races due to o!r causes4--,c]ta9 o!r causes1 accid5tal r ?an normal to a /ream1 result 9 ! developm5t ( t]races f flood-pla9s4 7#a7 ,if !re be uplift 9 a region :]e ! riv]s h flats1 ! /reams are rejuv5at$1 & ! remnants ( _! =m] flood-pla9s become t]races4 7#b7 ,if an alluvial flood-pla9 has be5 built z ! result ( an excessive supply ( s$im5t 7p4 #ahf71 ! exhau/ion or )drawal ( ! excessive supply w\ld leave ! /ream aga9 relatively cle>1 & free to erode :]e x _h be5 deposit+4 ,x w\ld =?) set to "w to c>ry away ! mat]ial :i* x _h tempor>ily unload$ on ! pla94 ,! pla9s built up 9 _m valleys 9 ! nor!rn "p ( our cont95t dur+ ! glacial p]iod1 :5 ! dra9age f ! ice c\rs$ ?r\gh !m1 h subsequ5tly be5 p>tially de/roy$ by erosion1 & _! remnants h become t]races4 ,a notable r$uction 9 ! am\nt ( available s$im5t1 ev5 :5 ! e>li] supply 0 n excessive1 produces a simil> result4 7#c7 ,a notable increase 9 ! volume ( a /ream1 )\t correspond+ increase 9 load1 z :5 "o /ream captures ano!r1 may occasion ! developm5t ( t]races by all[+ ! /ream to deep5 its *annel4 7#d7 ,above any b>ri] :i* dams a /ream1 a flood-pla9 is likely to be develop$4 ,:5 ! b>ri] is remov$ ! /ream w cut m or less deeply into ! pla9 above1 leav+ t]races4 7#e7 ,! recession ( a falls ?r\gh a flood-pla9 conv]ts su* p>ts ( x z rema91 into t]races4 ,9 conclusion1 x may be /at$ t _m riv] t]races1 mo/ly v l[1 are normal features ( valley developm5t1 com+ into exi/5ce at def9ite /ages 9 a valley's hi/ory4 ,!y are g5]ally compos$1 9 l>ge "p1 ( riv] alluvium4 ,o!rs result f m or less accid5tal causes1 work+ s+ly or 9 conjunction1 & to ?is class belong all ( ! m conspicu\s t]races develop$ f flood-pla9s4 ,! /ructure ( a t]race (t5 af=ds "s clue to its orig9 7,fig4 #aif74 ,illu/ration3 ,fig4 #aif4--,t]races p>tly ( rock & p>tly ( alluvium4 ,su* t]races indicate successive uplifts1 or "s o!r *ange :i* _h a simil> effect on ! /ream :i* made ! valley4 ,discont9uity ( t]races4--,:5 a /ream s9ks its *annel into its flood-pla91 x does n foll[ t a t]race rema9s on ea* side4 ,:]e ! /ream's deep5$ *annel is 9 ! middle ( its flood-pla91 !re is1 tempor>ily1 a t]race on ei!r side2 b :]ev] ! deep5$ *annel is at "o m>g9 ( its flood-pla91 a t]race rema9s on ! o!r side only4 ,ev5 :]e cont9u\s at ! outset1 t]races soon become discont9u\s1 = all processes ( subarial erosion conspire to de/roy !m4 ,a /ream is likely to me&] on its second & lat] flood-pla9s1 z on its fir/ & highe/ "o4 ,:]ev] ! me&]s on its second flood-pla9 rea* ! bord]s ( ! fir/ flood-pla91 ! t]race at t po9t disappe>s1 & s9ce ! me&]s are cont9ually migrat+1 t]races are cont9ually disappe>+4 ,! same w\ld be true ( ! second t]race1 if a second 7 develop$4 ,! removal ( portions ( a t]race by ! sweep ( me&]s is likely to leave ! remnants cuspate t[>d ! /ream4#ia ,aga91 tribut>y /reams1 9 br++ _! *annels into topographic adju/m5t ) _! ma9s1 cut ?r\gh ! t]races ( ! latt]4 ,new gullies develop on ! faces ( ! t]races & _! heads "w back across !m1 dissect+ !m /ill fur!r4 ,at ! same "t1 %eet erosion & o!r phases ( slope wa% t5d to drive ! sc>ps ( ! t]races back t[>d ! bluff beyond4 ,by ! "t a second s]ies ( t]races is well develop$1 no m ?an meagre remnants ( ! fir/ may rema94 ,f ! =ego+ consid]ations x is cle> t ! ext5t to :i* riv] t]races once develop$1 n[ rema91 is dep5d5t 9 "p on ! l5g? ( "t :i* has elaps$ s9ce ! riv] sank its *annel bel[ !m4 ,o!r ?+s be+ equal1 ! great] _! age ! m meagre _! remnants4 ,t]races develop$ f riv] pla9s =m$ *iefly by alluviation /& a bett] *ance ( long life ?an mo/ o!r alluvial t]races4 ,?is is because ( ! configuration ( ! orig9al valley1 ! aggradation ( :i* gave orig9 to ! pla94 ,! pr9ciple involv$ is illu/rat$ by ,fig4 #aig4 ,9 develop+ ! second flood-pla9 ! riv] enc\nt]s ! rock wall ( ! valley4 ,?is greatly ret>ds lat]al erosion1 & ! t]race above1 def5d$#ib by ! rock1 is likely to be long-liv$4 ,illu/ration3 ,fig4 #aig4--;,diagram to %[ :y c]ta9 t]races are long] liv$ ?an o!rs4 ,alluvial t]races1 l rock %elves1 are popul>ly ?\ght to m>k 8old levels ( ! riv]40 ,9 "o s5se ?is is true1 b n 9 ! s5se 9 :i* ! expression is commonly us$4 ,e level1 f ! cre/ ( ! b\nd+ bluffs to ! bottom ( a valley1 is a level at :i* wat] ran = a long] or %ort] "t2 b ! t]race does n mean t ! riv] 0 once s mu* l>g] ?an n[ z to fill ! valley f its pres5t *annel to ! level ( ! t]races4 ,t]m9i ( t]races4--,f ! mode ( developm5t ( t]races x w be se5 t1 trac$ up-/ream1 ea* t]race %\ld !oretically grade into a flood-pla9 at its upp] end 7,fig4 #aid71 & t ! upp] end ( ! second 7f ! top7 t]race1 :]e !re are two1 w\ld n be s f> up-/ream z ! upp] end ( ! fir/ 7highe/74 ,?is is repres5t$ diagrammatically 9 ,fig4 #aih4 ,! d[n-/ream t]m9i ( t]races are r>ely di/9ct4 ,?is is p>tly because ! notable me&]+ ( ! /reams 9 _! l[] c\rses is antagoni/ic to ! pres]vation ( t]races4 ,if all t]races once develop$ rema9$1 & if delta-build+ proce$$ )\t int]ruption f waves1 ! relations %\ld be some:at z foll[s3 ,trac$ d[n-/ream1 ! cliff betwe5 ! olde/ 7highe/7 t]race & ! next y\ng] becomes gradually l[] until x f9ally disappe>s1 & ! cont9uation ( ! two is f\nd 9 a common pla94 ,! cliff betwe5 ! second & ?ird t]races %\ld disappe> 9 ! same way1 & bel[ its disappe>ance ! pla9 repres5t+ _! cont9uation is cont9u\s ) t repres5t+ ! cont9uation ( ! fir/ & second4 ,! cliff betwe5 ! second & ?ird t]races may or may n cont9ue f>!r d[n-/ream ?an t betwe5 ! fir/ & second4 ,! pla9s bel[ ! t]races f9ally become cont9u\s ) ! l[e/ flood-pla9 & ) ! delta4 ,^! relations c r>ely be se5 because ( ! de/ruction ( ! old] t]races1 & because ( ! erosion by waves along %ore4 ,illu/ration3 ,fig4 #aih4--;,diagram look+ up ! valley1 %[+ two t]races bel[1 "o 9 ! middle1 & none above4 ,! relations are purely diagrammatic4 ,! topography ( t]races is simil> to t ( flood-pla9s1 except 9 s f> z modifi$ by erosion4 ,:ile flat 9 g5]al1 ! t]race may slope ei!r t[>d or f ! valley bluff1 & its surface may be m>k$ by all ! m9or irregul>ities :i* *>act]ize a flood-pla94 ,,*apt] ,,iv4 ,,! ,,"w ,,( ,,gr\nd- 7,,und]gr\nd7 ,,wat]4 ,_m famili> facts demon/rate ! g5]al pres5ce ( abundant wat] b5ea? ! surface ( ! l&4 ,! ?\s&s ( wells 9 regions peopl$ by civiliz$ races1 & ! c\ntless spr+s :i* issue f ! sides ( m\nta9s & valleys are a suffici5t pro( bo? ( ! wide di/ribution ( gr\nd-wat] & ( its great abundance4 ,c]ta9 well-kn[n facts make x cle> t gr\nd-wat] is intimately connect$ ) ra9fall4 ,9 a dry season ! level ( ! wat] 9 wells commonly s9ks1 & aft] a heavy ra9 x rises 7p4 #ga72 & ! am\nt ( s9k+ is great] :5 ! dr\ght is long1 & ! rise is mo/ notable :5 ! ra9fall is heavy4 ,_m spr+s :i* dis*>ge l>ge quantities ( wat] dur+ a wet season fl[ ) r$uc$ volume1 or cease to fl[ altoge!r 9 p]iods ( dr\ght4 ,fur!rmore1 ! wat] ( spr+s & wells has ! prop]ties :i* ra9-wat] w\ld possess aft] s9k+ b5ea? ! surface & dissolv+ m9]al sub/ances4 ,ra9-wat] is se5 to s9k b5ea? ! surface ) e %[]1 & s9ce ?is s\rce seems altoge!r adequate = gr\nd-wat]1 & s9ce no o!r s\rce is kn[n :5ce any consid]able am\nt ( gr\nd-wat] might come1 x is conclud$ t atmosph]ic precipitation is its *ief s\rce4 ,wat] gets b5ea? ! surface by processes :i* are readily se54 ,:]ev] ! soil is por\s "s ( ! ra9 :i* falls ^u x is absorb$4 ,s9k+ ?r\gh ! soil to ! solid rock x f9ds cracks & pores ?r\gh :i* x desc5ds to great dep?s4 ,n[h]e are ! rocks b5ea? ! mantle rock s compact & s free f cracks1 :5 any consid]able area is consid]$1 z to prev5t ! p]colation ( wat] ?r\gh !m4 ,conditions influ5c+ desc5t ( ra9-wat]4--,!re are sev]al conditions :i* influ5ce n only ! am\nt ( wat] :i* s9ks b5ea? ! surface 9 a giv5 area1 b ! proportion ( ! precipitation :i* foll[s ?is c\rse4 ,^! are z foll[s3 7#a7 ,am\nt ( precipitation4--,9 a g5]al way x is true t ! great] ! am\nt ( precipitation ! great] ! am\nt ( wat] :i* w s9k b5ea? ! surface4 ,o!r ?+s be+ equal1 a region ( heavy precipitation is a region :]e wells are easily obta9$ & spr+s common4 7#b7 ,rate ( precipitation4--,a giv5 am\nt ( precipitation may be conc5trat$ 9 a %ort int]val1 or di/ribut$ ?r\gh a consid]able p]iod ( "t4 ,9 ! latt] case m ( ! wat] s9ks b5ea? ! surface2 9 ! =m]1 a l>g] proportion runs (f ov] ! surface4 ,! reason is readily se54 ,wat] passes ?r\gh small spaces1 su* z ^? ( soil1 sl[ly1 & its rate ( passage decreases rapidly ) decreas+ size ( ! passageways4 ,:5 ra9 falls rapidly on a surface ( ev5 mod]ately close texture1 ! upp]mo/ lay] ( soil is promptly fill$ ) wat]1 & s9ce ! wat] passes d[nw>d sl[ly1 ! upp]mo/ saturat$ "p ( ! soil becomes virtually imp]vi\s4 ,:ile 9 ?is condition1 ! wat] :i* falls on x w run (f if !re be slope1 & /& if !re be none4 ,9 ! latt] case x w s9k sl[ly z ! wat] 9 ! soil passes d[n to l[] levels4 ,if precipitation takes place no fa/] ?an ! wat] c s9k ?r\gh ! soil1 all ! wat] may become gr\nd-wat]4 7#c7 ,! topography ( ! surface has mu* to d ) det]m9+ ! proportion ( ra9fall :i* becomes gr\nd-wat]4 ,if ! surface be flat1 m w s9k 92 if x be slop+1 m ( x w run (f be=e x has "t to s9k4 ,o!r ?+s be+ equal1 ! /eep] ! slope ! l>g] ! proportion ( ! ra9fall :i* w run (f ov] x4 7#d7 ,! texture ( ! soil1 or o!r mat]ial on :i* ! ra9 falls1 helps to det]m9e :at proportion ( x s9ks b5ea? ! surface4 ,if ! surface mat]ials be por\s1 ! wat] s9ks readily2 if ( close texture1 x f9ds less ready +ress4 ,o!r ?+s be+ equal1 ! clos] ! texture ( ! soil ! less ! proportion ( ! ra9fall :i* w ent] x4 7#e7 ,! texture & /ructure ( ! rock b5ea? ! surface h "s influ5ce on ! am\nt ( gr\nd-wat]4 ,! rock may be /ratifi$ or massive2 x may be abundantly or sp>sely jo9t$2 x may be por\s or compact4 ,on ! :ole1 /ratifi$ rock is m favorable = ! entrance ( wat] ?an un/ratifi$1 p>tly because ( its great] av]age porosity1 & p>tly because ! planes ( division betwe5 b$s (t5 all[ ! passage ( wat]4 ,if ! b$s ( /ratifi$ rock are v]tical or incl9$1 wat] f9ds its way into !m m readily ?an if !y are horizontal1 9 s f> z x desc5ds along /ratification planes4 ,horizontally b$d$ rock1 or rock :i* is n b$d$ at all1 may be s mu* jo9t$1 & ! jo9ts s op51 z to all[ ! wat] to ent] readily4 ,! conditions favorable to ! s9k+ ( abundant wat] bel[ ! surface are !re=e heavy precipitation1 fall+ sl[ly on a surface ) little relief1 a soil ( op5 texture und]la9 by rock :i* is por\s1 or affect$ by v]tical or highly incl9$ planes ( cleavage4 ,! annual dis*>ge ( wat] by riv]s is e/imat$ to be ab\t #bb p]c5t4 ( ! ra9fall on ! l&4#ic ,supply ( gr\nd-wat] n altoge!r dep5d5t on local ra9fall4--,! am\nt ( gr\nd-wat] 9 a giv5 region is n always entirely dep5d5t on ! local ra9fall4 ,gr\nd-wat] is 9 con/ant movem5t1 & ent]+ ! soil or rock at "o po9t x may1 aft] a long subt]ranean j\rney1 rea* a po9t f> f t at :i* x ent]$4 ,?us b5ea? ! ,great ,pla9s ( ! ,we/ !re is mu* subt]ranean wat] :i* fell on ! ea/]n slopes ( ! m\nta9s to ! we/4 ,x has fl[$ b5ea? ! surface to ! ,pla9s1 :]e "s ( x is n[ )drawn = ! purposes ( irrigation 9 regions :]e ra9fall is defici5t4 ,! accompany+ diagram 7,fig4 #aii7 illu/rates ! fl[ "h describ$4 ,illu/ration3 ,fig4 #aii4--;,diagram illu/rat+ ! g5]al po9t t gr\nd-wat] is n dep5d5t entirely ^u local supply4 ,illu/ration3 ,fig4 #bjj4--;,diagram illu/rat+ ! position ( ! gr\nd-wat] surface 7! dott$ l9e7 9 a region ( undulatory topography4 ,! gr\nd-wat] surface4 ,wat] table4--,! wat] table has already be5 def9$ 7p4 #ga7 z ! upp] surface ( ! gr\nd-wat]4 ,9 a flat region ( uni=m /ructure ! gr\nd-wat] surface is ess5tially level1 b rises & falls ) ! ra9fall4 ,:]e ! topography ( a region is n flat1 ! gr\nd-wat] surface is n level4 ,z a rule x is high]1 ?\gh f>!r bel[ ! surface1 "u an elevation ?an "u surr\nd+ l[l&s1 z illu/rat$ by ,fig4 #bjj4 ,! explanation is n f> to seek4 ,if a hill ( s& be expos$ to ra9fall1 mo/ ( ! wat] fall+ on its por\s surface w s9k into x4 ,if ! precipitation cont9ues long en\gh1 z 9 a protract$ ra91 ! hill ( s& w be fill$ ) wat]1 ! wat] occupy+ ! int]/ices betwe5 ! gra9s4 ,if ! s& ( ! hill c\ld be remov$1 leav+ ! wat] :i* x conta9s on ! same area1 x w\ld con/itute a m\nd p]haps a ?ird or a f\r? z high z ! hill itself4 ,if unsupport$1 ?is m\nd ( wat] w\ld spread promptly 9 all directions until its surface 0 level4 ,:ile ! s& rema9s1 ! wat] 9 x con/itutes a m\nd1 & has a t5d5cy to spread4 ,x does 9 fact spread1 b s9ce ! process involves great friction ! spread+ is sl[4 ,) ! spread+ ! surface ( ! wat] 9 ! s& s9ks1 & s9ks fa/e/ at ! c5t] :]e x is highe/ 7b1 ,fig4 #bja74 ,if ! process 7 n int]rupt$ ! surface ( ! wat] 9 ! hill w\ld1 9 "t1 s9k approximately to ! level ( ! wat] 9 ! surr\nd+ l& 7d1 ,fig4 #bja72 b at e /age prec$+ ! la/1 ! surface ( ! wat] w\ld be high] b5ea? ! summit ( ! hill ?an else:]e1 ?\gh f>!r f ! surface4 ,9 regions ( ev5 mod]ate precipitation ! wat] surface b5ea? ! hills r>ely s9ks to ! level ( t 9 ! l[l&s adjac5t1 be=e be+ rais$ by fur!r ra9s4 ,illu/ration3 ,fig4 #bja4--;,diagram to illu/rate ! relations ( gr\nd-wat] to ! surface4 ,! wat]-level b5ea? ! l[l&s also s9ks4 ,"s ( x f9ds its way into valleys1 "s ( x s9ks to great] dep?s1 & "s ( x evaporates2 b s9ce ! wat] surface b5ea? ! elevation s9ks m rapidly ?an t b5ea? ! l[l&1 ! two approa* a common level4 ,_! diff]5ce w be lea/ at ! end ( a dr\ght1 & greate/ j aft] heavy ra9s4 ,dep? to :i* gr\nd-wat] s9ks4--,! dep? to :i* gr\nd-wat] p5etrates has n be5 det]m9$ empirically4 ,no bor+s or excavations ( any sort h be5 made to su* dep?s z to indicate t its limit 0 be+ approa*$1 ?\gh "s ( !m are a mile or m deep4 ,!re is a popul> belief t wat] s9ks until x rea*es a temp]ature suffici5t to conv]t x into /eam1 b except = special localities :]e hot lava lies ne> ! surface1 ?is belief is n well f\nd$4 ,9 ! fir/ place1 x is n kn[n at :at temp]ature wat] bel[ ! surface w\ld be conv]t$ into /eam4 ,:ile wat] boils at sea-level at a temp]ature ( #bab 7,fahr47 a high] temp]ature w\ld be necess>y bel[ t level4 ,assum+ ! temp]ature ( wat] s9k+ b5ea? ! surface to be #ej ,fahr41 its temp]ature mu/ be rais$ #afb to br+ x to ! temp]ature at :i* x w\ld boil at sea-level4 ,on ! above assumption ( initial temp]ature1 ! foll[+ table %[s ! dep?s at :i* wat] w\ld rea* a temp]ature ( #bab ,fahr4 "u v>i\s assumptions z to ! rate ( increase ( temp]ature4 ,x %[s also ! pressure 9 atmosph]es :i* w\ld exi/ at ^! sev]al dep?s if ! ov]ly+ rock 7 full ( wat]4 ,dep? at :i* ,equival5t ,rate ( ,increase ,temp]ature ( #bab ,pressure 9 ( ,temp]ature4 w\ld be rea*$4 ,atmosph]es4 #a = #ej feet #h1ajj feet #bch 7approximately7 #a = #fj #i1gbj #bhe #a = #gj #aa1cdj #ccc ,) an initial temp]ature ( #hj1 correspond+ to t ( ! w>m] p>ts ( ! e>?'s surface1 in/ead ( #ej1 ! table w\ld be z foll[s3 #a = #ej feet #f1fjj feet #aid 7approximately7 #a = #fj #g1ibj #bad #a = #gj #i1bdj #bgb ,! temp]ature at :i* wat] boils increases ) ! pressure4 ,a pressure ( ab\t #bjj atmosph]es is ! critical pressure = wat]2 t is1 ! pressure :i*1 if increas$1 w prev5t boil+ altoge!r4 ,! dep? at :i* a pressure ( #bjj atmosph]es w\ld be rea*$1 suppos+ ! upp] rock to be full ( wat]1 is ab\t #fhjj feet4 ,! temp]ature ( ! wat] at ?is dep?1 "u v>i\s assumptions z to initial temp]ature & rate ( increase ( heat1 is %[n 9 ! foll[+ table3 ,rate ( ,increase ,temp]ature at a ,initial ,temp]ature4 ( ,temp]ature4 ,dep? ( #f1hjj ,feet4 #ej #a = #ej feet #ahf ,fahr4 #ej #a = #fj #afc #ej #a = #gj #adg #hj #a = #ej #baf #hj #a = #fj #aic #hj #a = #gj #agg ,only "o ( ^! temp]atures rea*es ! boil+-po9t ( wat] at sea-level4 ,x is !re=e cle> t at ?is dep? wat] has n ev5 closely approa*$ ! boil+ temp]ature = ?is dep?1 & s9ce ?is is ! dep? ( ! critical pressure1 x is cle> t x _c boil at any great] dep?4 ,! desc5t ( wat] is !re=e n /opp$1 "u normal conditions ( cru/al temp]ature1 because x rea*es its boil+-po9t4 ,locally1 z 9 ! vic9ity ( active or rec5tly ext9ct volcanoes1 ! case may be diff]5t4 ,x is conceivable t wat] may desc5d until x rea*es its critical temp]ature 7some:]e betwe5 #faj & #fce ,fahr474 ,! dep? at :i* ! critical temp]ature w\ld be rea*$1 "u v>i\s assumptions1 is %[n 9 ! foll[+ table3 ,rate ( ,increase ,dep? ( ,critical ,initial ,temp]ature4 ( ,temp]ature4 ,temp]ature4 #ej #a = #ej feet #bh1jjj to #bi1bej feet #ej #a = #fj #cc1fjj to #ce1ajj #ej #a = #gj #ci1bjj to #dj1iej #hj #a = #ej #bf1ejj to #bg1gej #hj #a = #fj #ca1hjj to #cc1cjj #hj #a = #gj #cg1ajj to #ch1hej ,!re is good reason1 9 ! increas+ d5sity b5ea? ! surface1 = believ+ t ! rate ( increase ( temp]ature decreases ) dep?1 & !re=e t ! rate ( #a = #ej feet = ! dep?s conc]n$ is too high4 ,! great] dep?s ( ! table above are !re=e believ$ to m ne>ly repres5t ! tru? ?an ! less] ones4 7,see discussion ( und]gr\nd temp]ature 9 ,*apt] ,,xi47 ,if desc5d+ wat] atta9$ its critical temp]ature1 ! ext5t to :i* ! result+ wat]-gas might be absorb$ is n kn[n4 ,s f> z limit$ by temp]ature1 !re=e1 x is n possible to assign a limit to ! desc5t ( wat] "u av]age conditions ( cru/al temp]ature4 ,o!r consid]ations seem to place a limit to ! desc5t ( wat]4 ,rock1 solid & unyield+ z x seems1 is yet pla/ic :5 "u suffici5tly great pressure4 ,! cracks & cavities affect+ x are believ$ to desc5d a di/ance :i* is b slight 9 comp>ison ) ! radius ( ! e>?4 ,ev5 if op5+s 7 once =m$ at great] dep?s1 !y c\ld n p]si/1 = ! adjac5t rock1 "u ! pressure :i* !re exi/s1 w\ld 8fl[0 91 9 effect 7?\gh p]haps n 9 pr9ciple7 mu* z /iff liquid might1 & close !m4 ,! out] zone ( ! e>? :]e cavities may exi/ is kn[n z ! zone ( fracture4#id ,! dep? ( ! zone ( fracture diff]s = diff]5t rocks1 b is n believ$ to ext5d bel[ "s su* dep? z five or six miles1 ev5 = ! mo/ resi/ant4#ie ,x is to be not$ t ^! dep?s are less ?an ^? at :i* ! critical temp]ature ( wat] w\ld be rea*$ "u mo/ ( ! conditions1 includ+ all ! m probable ones1 specifi$ 9 ! above table4 ,let x be assum$ t wat] desc5ds ?r\gh op5+s 9 ! rock to a dep? ( six miles4 ,at ?is dep? x w\ld1 "u ! v>i\s assumptions specifi$ 9 ! fir/ & second columns ( ! foll[+ table1 h ! temp]ature indicat$ 9 ! ?ird column3 ,initial ,rate ( ,increase ,temp]ature at ,temp]ature4 ( ,temp]ature4 ,dep? ( ,six ,miles4 #ej #a = #ej feet #fhc ,fahr4 #ej #a = #fj #egh #ej #a = #gj #ejb #hj #a = #ej #gac #hj #a = #fj #fjh #hj #a = #gj #ecb ,9 two ( ^! cases1 namely1 ^? 9 :i* ! assum$ rate ( increase ( temp]ature is highe/1 ! temp]ature ( ! wat] at ! assum$ l[] limit ( ! zone ( fracture is above ! critical temp]ature ( wat]4 ,if ! assumptions involv$ 9 ^! two cases be correct1 wat] might desc5d to ! po9t :]e x w\ld be conv]t$ into wat]-gas1 & 9 ?is condition x might be occlud$ by ! hot rock4 ,9 ! o!r cases1 involv+ ! m probable assumptions1 ! critical temp]ature is n rea*$ at a dep? ( six miles4 ,if pores & cracks d n ext5d to great] dep?s1 liquid wat] c\ld n2 & s9ce ! wat] at ?is dep? has probably n rea*$ its critical temp]ature1 x _c exi/ z wat]-gas4 ,if x does n exi/ 9 ! =m ( wat]-gas1 its occlusion by ! hot rock sub/ance w\ld n be probable4 ,x w\ld seem1 !re=e1 t ! desc5t ( wat] "u ord9>y conditions is mu* m likely to be limit$ by ! zone ( fracture1 ?an by temp]ature4 ,movem5t ( gr\nd-wat]4#if--;,gr\nd-wat] is 9 m or less cont9ual movem5t4 ,if all ! wat] be pump$ out ( a well x soon fills up aga9 to its normal level by infl[ f all sides4 ,spr+s & fl[+ wells also demon/rate ! movem5t ( gr\nd-wat]4 ,ne> ! surface ! movem5t ( gr\nd-wat] is prim>ily d[nw>d if ! m$ium ?r\gh :i* x passes is equally p]meable 9 all directions2 b s soon z ! desc5d+ wat] rea*es ! wat] surface1 its desc5t is *eck$ & its movem5t is p>tly lat]al4 ,! commone/ sort ( movem5t ( gr\nd-wat] is t exemplifi$ z ! wat] s9ks b5ea? ! surface1 namely1 sl[ p]colation ?r\gh ! pores & cracks ( ! soil & rock4 ,gr\nd-wat] is n g5]ally organiz$ into def9ite /reams1 ?\gh und]gr\nd /reams1 mo/ly small1 are sometimes se5 9 caves & crevices1 & sometimes issue z spr+s4 ,mo/ und]gr\nd /reams :i* issue z spr+s probably h def9ite *annels = %ort di/ances only be=e !y issue4 ,x is probable t gr\nd-wat] frequ5tly fl[s 9 consid]able quantity along some:at def9ite planes1 )\t hav+ op5 *annels4 ,?us e por\s b$ ( rock is likely to s]ve z ! pa?way along :i* subt]ranean dra9age passes4 ,?is is especially true :]e ! por\s b$ is und]la9 by an imp]vi\s "o4 ,! 8res]voirs0 f :i* artesian wells draw _! supply are n usually /reams or lakes1 b por\s b$s ( rock ?r\gh :i* abundant wat] passes4 ,z ! supply is drawn (f at "o po9t1 x is r5ew$ by wat] ent]+ else:]e4 ,s9ce ! fre$om ( movem5t ( gr\nd-wat] is notably influ5c$ by ! porosity ( ! rock1 & s9ce ! rock is1 on ! av]age1 mo/ por\s & ! pores l>ge/ ne> ! surface1 ! movem5t ( gr\nd-wat] is1 on ! av]age1 greate/ ne> ! surface1 & lea/ at its l[] limit4 ,9 g5]al ! decrease ( movem5t is mu* m rapid ?an ! decrease 9 ! size ( ! pores4 ,x foll[s t :ile ! upp] "p ( ! gr\nd-wat]1 especially t above gr\nd-wat] level1 moves some:at freely1 ! l[] "p moves mu* m sl[ly4 ,x is probable1 inde$1 t ! movem5t 9 ! l[] "p ( ! subt]ranean hydrosph]e is extremely slight4 ,! am\nt ( gr\nd-wat]4--,! porosity ( surface rocks v>ies widely1 & ! porosity ( b few has be5 det]m9$4#ig ,su* det]m9ations z h be5 made are *iefly on build+ /ones1 9 :i* ! range ( porosity v>ies f a fraction ( "o p]c5t41 9 ! case ( granite1 to ne>ly #cj p]c5t4 9 ! case ( "s s&/ones4 ,build+ /one is p]haps m d5se ?an ! av]age surface rock4 ,fur!rmore1 su* te/s z h be5 made d n take acc\nt ( ! l>g] cracks & op5+s ( rock1 = ^! w\ld n appe> 9 ! specim5s te/$2 nor ( ! mantle rock1 :i* g5]ally conta9s a l>ge am\nt ( wat]4 ,f su* det]m9ations z h be5 made x is e/imat$ t ! av]age porosity ( ! out] "p ( ! li?osph]e is some:]e betwe5 #e & #aj p]c5t4 ,if ! porosity dim9i%es regul>ly to a dep? ( six miles1 :]e x becomes z]o1 ! av]age porosity to ?is dep? w\ld be half ! surface porosity4#ih ,an av]age porosity ( two & "o-half p]c5t4 w\ld mean t ! rock conta9s en\gh wat] to =m a lay] ne>ly #hjj feet deep4 ,) an av]age porosity ( #e p]c5t41 ?is figure w\ld be d\bl$4#ii ,:ile ^! figures are n to be reg>d$ z measurem5ts1 !y p]haps give "s idea ( ! am\nt ( gr\nd-wat]4 ,x is ?is sph]e ( gr\nd-wat] :i* ju/ifies ! t]m hydrosph]e1 z appli$ to ! wat]s ( ! e>?4 ,fate ( gr\nd-wat]4--,mo/ ( ! wat] :i* s9ks into ! e>? rea*es ! surface aga9 aft] a long] or %ort] j\rney4 ,"s ( x is evaporat$ f ! surface directly2 "s ( x is tak5 up by plants & is pass$ by !m into ! atmosph]e2 "s ( x issues 9 ! =m ( spr+s2 "s ( x seeps out2 "s ( x is drawn out ?r\gh wells2 & mu* ( ! rema9d] f9ds its way und]gr\nd to ! sea or to lakes1 issu+ z spr+s b5ea? !m4 ,a small portion ( ! desc5d+ wat]s ent]s into p]man5t comb9ation ) m9]al matt]4 ,_m m9]als are kn[n to take up wat]1 be+ *ang$ !reby f an anhydr\s to a hydr\s condition4 ,x does n necess>ily foll[1 h[ev]1 t ! total supply ( wat] is !reby decreas+4 ,m9]als once hydrat$ may be dehydrat$ subsequ5tly1 ! wat] be+ set free4 ,fur!rmore1 consid]able quantities ( wat] 9 ! =m ( vapor issue f volcanoes1 & volcanic v5ts (t5 cont9ue to /eam long aft] volcanic action prop] has ceas$4 ,x is probable t "s1 & p]haps mu* ( ! wat] issu+ f ^! v5ts has nev] be5 at ! surface be=e1 & x is n n[ possible to affirm t ! supply f ?is s\rce does n (fset1 or ev5 surpass1 ! depletion ( ! hydrosph]e result+ f m9]al hydration4 ,,! ,,"w ,,( ,,gr\nd-,,wat]4 ,gr\nd-wat] effects v consid]able results 9 ! c\rse ( its hi/ory4 ,^! results are p>tly *emical & p>tly me*anical1 ! =m] be+ f> m important ?an ! latt]4 ,*emical ,"w4 ,! results ( ! *emical & *emico-physical action ( wat] may be gr\p$ 9 sev]al m or less di/9ct categories4 #a4 ,! simple/ effect is ! subtraction ( soluble m9]al matt]4 ,pure wat] is 9 itself a solv5t ( c]ta9 m9]als2 b ! c>bonic-acid gas extract$ f ! atmosph]e1 & ! products ( organic decay extract$ f ! soil make gr\nd-wat] a mu* m effici5t solv5t4 ,some?+ ( ! results :i* x a*ieves is %[n by its composition4 ,all gr\nd-wat]1 :e!r issu+ z spr+s or drawn out ?r\gh wells1 conta9s mu* m m9]al matt] ?an ! wat] :i* falls z ra91 & ! excess is acquir$ 9 its und]gr\nd c\rse4 ,! subtraction ( soluble matt] f rock r5d]s x por\s4 ,! am\nt ( mat]ial dissolv$ f a giv5 place may be trivial or consid]able1 accord+ to ! "* ( ! rock1 ! read9ess ) :i* wat] has access to x1 & ! "* ( ! wat]4 ,locally1 ! subtraction ( m9]al matt] may be ! *ief1 or ev5 ! only appreciable1 effect ( ! gr\nd-wat]4 #b4 ,x sometimes happ5s t gr\nd-wat] ) c]ta9 m9]al sub/ances 9 solution ex*anges !m = o!r sub/ances extract$ f ! rock4 ,?us ! process ( sub/itution is effect$4 ,by ?is process ! lime c>bonate ( a %ell imb$d$ 9 rock may be remov$1 molecule by molecule1 & "s o!r sub/ance1 su* z silica1 left 9 its place4 ,:5 ! process is complete1 ! sub/ance ( ! %ell has be5 completely remov$1 ?\gh its =m & /ructure are /ill pres]v$ 9 ! new mat]ial :i* has tak5 ! place ( ! old4 ,buri$ logs are sometimes conv]t$ into /one by ! sub/itution ( m9]al matt] = ! vegetable tissue4 ,?is is petrification4 ,petrification is altoge!r di/9ct f incru/ation1 :i* simply means ! coat+ ( an object ) m9]al matt]4 ,a bird's ne/ may be incru/$ ) lime c>bonate1 b x is n !reby petrifi$4 ,solution is a necess>y antec$5t ( sub/itution4 #c4 ,! mat]ials :i* are subtract$ f ! rock at "o po9t may be add$ to o!r rock else:]e4 ,?us a ?ird type ( *ange1 addition1 is effect$4 ,rock may at "o "t & place be r5d]$ por\s by ! subtraction ( "s ( its sub/ance1 & ! op5+s ?us =m$ may subsequ5tly become ! receptacles ( deposits f solution4 ,?is is exemplifi$ 9 ! /alactitic deposits ( _m caves4 ,n uncommonly cracks & fissures are fill$ ) m9]al matt] deposit$ by ! wat]s :i* pass ?r\gh !m4 ,?us arise ve9s :i*1 = ! mo/ "p1 are no?+ m ?an cracks & crevices fill$ by m9]al matt] br\ght to !m 9 solution1 & precipitat$ on _! walls4 ,mo/ ve9s ( metallic ores h orig9at$ 9 ?is way4 #d4 ,a fur!r s]ies ( *anges is effect$ by gr\nd-wat] :5 x1 or ! m9]al matt] x conta9s1 ent]s into comb9ation ) ! m9]al matt] ?r\gh :i* x passes4 ,"o ( ! commone/ processes ( ?is sort1 hydration1 has already be5 ref]r$ to 7pp4 #dc & #dbh72 b 9 ! developm5t ( _m ( ! common] hydr\s m9]als *anges o!r ?an hydration are involv$4 ,^! *anges result 9 new m9]al comb9ations1 ! new m9]als be+ develop$ out ( ! old1 usually ) "s additions or subtractions4 ,9 ! long c\rse ( "t *anges ( ?is sort may be v great1 s great inde$ t l>ge bodies ( rock are radically *ang$1 bo? *emically & physically4 ,mu* ( ! old sub/ance may rema91 b x has ent]$ into new & m /able comb9ations ) ! mat]ials :i* ! wat] has br\ght to x4 ,quantitative importance ( solution4--,9 g5]al1 solution is probably mo/ effective at a relatively slight di/ance bel[ ! surface4 ,9 ! out]mo/ zone ( mantle rock ! mat]ials are usually less soluble ?an bel[1 = !y (t5 repres5t ! residuum aft] ! soluble p>ts ( ! =mation f :i* !y orig9at$ 7 dissolv$ out4 ,bel[ ?is zone ! rock conta9s m soluble matt]1 & ! wat]1 *>g$ ) organic matt] 9 its desc5t ?r\gh ! soil1 is 9 condition to dissolve x4 ,at great] dep?s ! wat] has become saturat$ to "s ext5t1 &1 s f> =?1 less active4 ,"h1 too1 ! movem5t is less free4 ,! increas$ pressure at consid]able dep?s1 on ! o!r h&1 facilitates solution1 :i* mu/ be und]/ood to take place "u prop] circum/ances 9 any zone rea*$ by ! wat]4 ,calculations h be5 made :i* illu/rate ! quantitative importance ( ! solution effect$ by gr\nd-wat]4 ,! spr+s ( ,leuk 7,switz]l&7 br+ to ! surface annually m ?an #bjjj tons ( calcium sulphate 7gypsum7 9 solution1 & 9 ! same "t ! spr+s ( ,ba? 7,engl&7 br+ up an am\nt ( m9]al matt] 9 solution suffici5t to make a column #i feet 9 diamet]1 & #adj feet high4#ajj ,! am\nt ( m9]al matt] 9 solution 9 /reams is also significant1 = :ile /ream-wat] is n all d]iv$ f gr\nd-wat]1 mu* ( x _h su* an orig94 ,9 ! case ( sev]al /reams1 among !m ! ,?ames & ! ,elbe1 c>eful e/imates ( ! am\nt ( dissolv$ m9]al matt] h be5 made4 ,?\gh ! ,?ames dra9s an area only ab\t "o-t5? z l>ge z ! ,/ate ( ,new ,york1 x is e/imat$ to c>ry ab\t #aejj tons ( m9]al matt] 9 solution to ! sea daily4#aja ,f ! upp]mo/ #bj1jjj squ>e miles ( its dra9age bas9 ! ,elbe is e/imat$ to c>ry ye>ly ab\t #a1cgj1jjj tons ( m9]al matt] 9 solution4 ,e/imates ( ! am\nts ( mat]ial c>ri$ to ! sea 9 solution by sev]al riv]s are giv5 on pp4 #ajb & #ajc4 ,mu* ( ?is matt] 0 br\ght to ! riv]s by wat]s :i* _h be5 und]gr\nd be=e rea*+ ! /reams4 ,f ^! figures x is cle> t we h to reckon "h ) a v consid]able factor 9 ! l[]+ ( l& surfaces4 ,f ! am\nt ( lime c>bonate c>ri$ by ! ,?ames x has be5 e/imat$ t ! av]age am\nt ( ?is mat]ial dissolv$ f ! lime/one area dra9$ by ?is /ream is #adcajb tons p] squ>e mile p] ye>4 ,x is e/imat$ t1 on ! av]age1 some?+ l "o-?ird z mu* matt] is c>ri$ to ! sea 9 solution z 9 ! =m ( s$im5t1 & t by ?is process alone l& areas w\ld be l[]$ some?+ l "o foot 9 #ac1jjj ye>s4#ajc ,deposition ( m9]al matt] f solution4--,! deposition ( mat]ial f solution is effect$ 9 sev]al ways4 7#a7 ,x is sometimes deposit$ by evaporation4 ,?is is well %[n :]e wat] seeps out on arid l&s4 ,! same process is illu/rat$ :5 wat] is boil$4 7#b7 ,r$uction ( temp]ature (t5 occasions deposition4 ,9 g5]al1 hot wat] is a bett] solv5t ( m9]al matt] ?an cold1#ajd & if x issues ) abundant m9]al matt] 9 solution ! precipitation ( "s ( x is likely to take place4 7#c7 ,plants sometimes cause ! precipitation ( m9]al matt] f solution4 ,ab\t "s hot spr+s1 ev5 :]e ! temp]ature ( ! wat] is v high small plants ( l[ type 7alg7 gr[ 9 pr(usion4 ,9 ways :i* are n p]fectly und]/ood ^! alg extract ! m9]al matt] f ! hot wat]4 ,!y are n[ ?\ght to be a *ief factor 9 ! deposits ab\t ! hot spr+s ( ! ,yell[/one ,p>k4#aje ,! influ5ce ( organisms on precipitation f solution is n conf9$ to ! wat]s ( hot spr+s4 7#d7 ,a f\r? factor involv$ 9 ! deposition ( m9]al matt] f solution is pressure4 ,pressure increases ! solv5t p[] ( wat] ) respect to m9]als directly2 x produces ! same effect indirectly by its effect on ! solution ( gases4 ,z wat] *>g$ ) gas comes to ! surface1 ! pressure is reliev$ & "s ( ! gas escapes4 ,su* m9]al matt] z 0 held 9 solution by ! help ( ! gas :i* escapes is !n precipitat$4 7#e7 ,precipitation is also sometimes effect$ by ! m+l+ ( wat]s conta9+ diff]5t m9]al sub/ances 9 solution4 ,su* m+l+ ( solutions w\ld be mo/ common along l9es ( ready subt]ranean fl[1 & :ile ea* portion ( ! wat] ent]+ a crevice or por\s b$ may be able to keep its own m9]al matt] 9 solution1 _! m+l+ may involve *emical *anges result+ 9 ! =mation ( insoluble comp\nds1 & !re=e 9 deposition4 ,?is pr9ciple has probably be5 involv$ 9 ! fill+ ( _m fissures & crevices1 conv]t+ !m into ve9s4 7#f7 ,! escape ( gases f wat]1 :e!r f increase ( temp]ature or by ! di/urbance ( wat]1 sometimes causes ! deposition ( m9]al matt] held 9 solution4 ,! deposition ( mat]ial held 9 solution is mo/ notable at two zones1 "o bel[ t ( mo/ active solution1 & ! o!r at ! surface1 :]e evaporation is active4 ,"u prop] conditions1 h[ev]1 deposition may take place at any level rea*$ by wat]4 ,me*anical ,"w4 ,! me*anical "w ( gr\nd-wat] is relatively unimportant4 ,:]ev] x is organiz$ into def9ite /reams1 ! *annels ?r\gh :i* x fl[s are likely to be increas$ by me*anical erosion z well z by solution4 ,ei!r b5ea? ! surface1 or aft] ! /reams issue1 ! me*anical s$im5t c>ri$ w be deposit$4 ,illu/ration3 ,fig4 #bjb4--;,diagram to illu/rate ! g5]al =m & relations ( caves develop$ by solution4 ,! black portions repres5t ! cav]n spaces4 ,"s lime/one s9ks are repres5t$ on ! surface above4 ,,results ,,( ,,! ,,"w ,,( ,,gr\nd-,,wat]4 ,illu/ration3 ,fig4 #bjc4--;,gr\nd-plan ( ,wy&otte ,cave4 ,! un%ad$ areas repres5t ! passageways4 7#ba/ ,ann4 ,rept41 ,ind4 ,geol4 ,surv47 ,wea!r+4--,:]e ! solution effect$ by gr\nd-wat] 9 any locality is slight & equally di/ribut$1 ! result is to make ! rock por\s4 ,if1 = example1 "s ( ! cem5t ( s&/one is dissolv$1 ! texture ( ! rock becomes m op52 b if all ! cem5t be remov$ ! rock is *ang$ f s&/one to s&4 ,if a complex cry/all9e rock conta9s among its _m m9]als "s "o :i* is m soluble ?an ! o!rs1 t "o may be dissolv$4 ,?is has ! effect ( break+ up ! rock1 s9ce ea* m9]al acts z a b9d] = ! re/4 ,x might happ5 t no "o ( ! m9]als is dissolv$ completely1 b t "s "o ( !m is decompos$ by wat]1 & c]ta9 ( its con/itu5ts remov$4 ,su* *ange w\ld be likely to cause ! m9]al s affect$ to crumble1 & ) its crumbl+1 if x be an important con/itu5t ( ! rock1 ! integrity ( ! rock is de/roy$4 ,:]e consid]able *emical *anges1 especially subtractions1 are go+ on1 ! rock is likely to crumble4 ,! increase 9 volume att5dant on hydration1 etc41 sometimes leads to ! disruption ( rock4 ,^! are phases ( wea!r+4 7,= o!r phases ( wea!r+ see pp4 #ed & #aaj47 ,cav]ns4#ajf--,:]e local solution is v great results ( ano!r sort may be effect$4 ,9 =mations l lime/one1 :i* are relatively soluble1 consid]able quantities ( mat]ial are frequ5tly dissolv$ f a giv5 place4 ,in/ead ( mak+ ! rock por\s1 9 ! usual s5se ( ! t]m1 l>ge cav]ns may be develop$ 7,fig4 #bjb74 ,9 _! production1 solution may be abett$ by ! me*anical action ( ! wat] pass+ ?r\gh ! op5+s :i* solution has develop$4 ,consid]able caves are f\nd *iefly 9 lime/one4 ,!y 7 probably develop$ :5 ! surface relief 0 slight1 & surface dra9age !re=e poor4 ,regions :]e caves 7 develop$ "u ^! conditions may subsequ5tly acquire relief1 s t caves are n n[ conf9$ to flat regions4 ,"o ( ! be/ kn[n regions ( caves is 9 ! bas9 ( ! ,ohio 9 ,k5tucky & s\!rn ,indiana1 :]e ! numb] ( caves is l>ge1 & ! size ( "s ( !m1 su* z ,mammo? & ,wy&otte1 v great4 ,a gr\nd-plan ( ,wy&otte 7,ind47 ,cave is %[n 9 ,fig4 #bjc4 ,! aggregate l5g? ( ! passageways is ab\t #bc miles4 ,illu/ration3 ,fig4 #bjd4--;,deposits 9 ,wy&otte 7,ind47 ,cave4 7,ha9s47 ,illu/ration3 ,fig4 #bje4--;,deposits 9 ,wy&otte ,cave4 7,ha9s47 ,deposition (t5 takes place 9 caves aft] !y are =m$ 7,figs4 #bjd & #bje74 ,x may ev5 g on at ! same "t t ! cave is be+ excavat$4 ,"h are =m$ ! well-kn[n /alactites & /alagmites4 ,a /alactite may />t f a drop ( wat] leak+ ?r\gh ! ro( ( ! cave4 ,evaporation1 or ! escape ( "s ( ! c>bonic gas 9 solution1 results 9 ! deposition ( "s ( ! lime c>bonate ab\t ! m>g9 ( ! drop1 9 ! =m ( a r+4 ,successive drops make successive deposits on ! l[] edge ( ! r+1 :i* gr[s d[nw>d into a holl[ tube ?r\gh :i* desc5d+ wat] passes1 mak+ its *ief deposits at ! end4 ,deposition 9 ! tube may ultimately close x1 :ile deposition on ! outside1 due to wat] trickl+ d[n 9 t position1 may greatly enl>ge x4 ,illu/ration3 ,fig4 #bjf4--;,a lime/one s9k-hole1 ea/-nor!a/ ( ,cambria1 ,wyo41 exceptional = its /eep sides4 ,m9nekahta lime/one4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,und]gr\nd caves sometimes give rise to topographic features :i* are ( local importance4 ,:5 ! solution ( mat]ial 9 a cav]n has gone s f> t its ro( becomes ?9 & weak1 x may collapse1 giv+ rise to a s9k or depression 9 ! surface ov] ! site ( ! orig9al cave4 ,?is is s common t regions ( lime/one caves are (t5 affect$ by frequ5t s9ks =m$ 9 ?is way4 ,!y are a conspicu\s feature ( ! l&scape 9 ! cave region ( ,k5tucky1 & are well kn[n 9 _m o!r lime/one di/ricts4 ,!y are kn[n z lime/one s9ks4 7,fig4 #bjf & ,fig4 #b1 ,pl4 ,,xvii47 ,illu/ration3 ,fig4 #bjg4--;,a fre% l&slide ne> ,m$ic9e ,lake1 ,mont4 ,! b>e space %[s ! position f :i* ! slide />t$4 7,:itney47 ,illu/ration3 ,fig4 #bjh4--,l&slide topography4 ,! protrud+ mass on ! "r has slump$ d[n f ! m\nta9 to ! left4 ,s\? face ( ,l&slip ,m\nta91 ,colo41 se5 f ! we/2 ,rico quadrangle4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,"u c]ta9 circum/ances caves may give rise to /rik+ features ( ano!r sort4 ,if = any reason ! ro( is de/roy$ at ! two ends ( a cave1 rema9+ intact ov] ! middle1 ! latt] "p con/itutes a natural bridge4 ,natural bridges also orig9ate 9 o!r ways 7pp4 #aea1 #aec74 ,illu/ration3 ,fig4 #bji4--,l&slide topography on ,badg] ,m\nta91 ,wa%+ton4 ,! slump+ mat]ial 9 ?is case is basalt4 ,creep1 slumps1 & l&slides4--,:5 ! soil & subsoil on a slope become *>g$ ) wat] !y t5d to move d[nw>d4 ,:5 ! movem5t is too sl[ to be s5sible x is call$ creep4 ,! common d[nw>d incl9ation ( trees gr[+ 9 su* situations1 ! result ( ! m rapid creep ( ! surface z comp>$ ) ! deep] "p ( ! soil1 is bo? an expression ( ! movem5t & ( its sl[ness4 ,o!r factors besides gr\nd-wat] are involv$ 9 creep 7see p4 #aab74 ,:5 ! movem5t is rapid en\gh to be s5sible ! mat]ial is said to slump or slide4 ,?is may happ5 :5 ! slope on :i* wat]-*>g$ mantle rock lies is /eep 7,fig4 #bjg74 ,great l&slides ( ?is sort h be5 record$1 & "s ( !m h done great damage4 ,:]e a /ream's banks are high1 & ( un9durat$ mat]ial1 su* z clay1 consid]able masses sometimes slump f ! bank or bluff into ! riv]1 or settle away sl[ly f _! =m] positions4 ,?is is a common ph5om5on along /reams :i* h cut valleys 9 drift1 & along %ores on :i* waves are encroa*+4 ,! same ph5om5on is common on a l>g] scale on ! slopes ( /eep m\nta9s4#ajg ,consid]able t]races are sometimes develop$ on _! slopes 9 ?is way1 b !y are usually irregul> & discont9u\s 7,figs4 #bjh1 & #bji74 ,! loose dbris on /eep slopes sometimes assumes a sort ( fl[+ motion & desc5ds ! slope ) "s su* =m & at "s su* rate z a glaci]4 ,su* bodies ( dbris are sometimes call$ 8talus glaci]s0 7,fig4 #baj74 ,9 _m su* cases1 sn[ & ice h _h "s "p 9 _! developm5t4 ,9 creep & 9 l&slides gravity is ! =ce involv$1 & ! gr\nd-wat] only a condition :i* makes gravity effective4 ,gravity alone accompli%es simil> results1 z illu/rat$ by ,fig4 #baa4 ,summ>y4 ,all 9 all1 gr\nd-wat] is to be look$ ^u z a mo/ important geological ag5t4 ,:5 x is rememb]$ t a v l>ge "p ( all ! wat] :i* falls on ! surface ( ! e>?1 ei!r 9 ! =m ( ra9 or sn[1 s9ks b5ea? ! surface2 t mu* ( x s9ks to a great dep?2 t mu* ( x has a long und]gr\nd c\rse be=e x reappe>s at ! surface2 t x is ev]y:]e & always active1 ei!r 9 subtract+ f ! rock ?r\gh :i* x passes1 9 add+ to x1 9 effect+ ! sub/itution ( "o m9]al sub/ance = ano!r1 or 9 br++ ab\t new *emical comb9ations2 & :5 x is rememb]$ t ?is process has be5 go+ on = untold millions ( ye>s1 x w be se5 t ! total result accompli%$ mu/ be /up5d\s4 ,! rock =mations ( ! e>? to ! dep?s to :i* gr\nd-wat] p5etrates are to be look$ ^u z a sort ( *emical laboratory ?r\gh :i* wat]s are circulat+ 9 all directions1 *>g$ ) all sorts ( m9]al sub/ances4 ,"s ( ! sub/ances 9 solution are deposit$ b5ea? ! surface1 & "s are br\ght to ! surface :]e ! wat]s issue4 ,mu* ( ! mat]ial br\ght to ! surface 9 solution is c>ri$ to ! sea & utiliz$ by m>9e organisms 9 ! mak+ ( %ells4 ,)\t ! m9]al matt] br\ght to ! sea by spr+s & riv]s1 _m %ell-be>+ animals ( great importance1 geologically1 w\ld p]i%4 ,biologically1 !re=e1 z well z geologically1 gr\nd-wat] is ( great importance4 ,illu/ration3 ,,plate ,,xvii4 ,fig4 #a4 ,,hunt]don ,,c\nty1 ,,new ,,j]sey4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,ne> ,,pikeville1 ,,t5nessee4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xviii4 ,fig4 #a4 ,,wa%+ton4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,cali=nia4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #baj4--;,a 8talus glaci]10 9 ,silv] ,bas91 ne> ,silv]ton1 ,colo4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #baa4--;,a huge mass ( rock settl+ into ! ,canyon ( ! ,colorado4 ,a result ( gravity action4 7,atwood47 ,,spr+s ,,& ,,fl[+ ,,wells4 ,! t]m spr+ is appli$ to any wat] :i* issues f b5ea? ! surface ) suffici5t volume to cause a di/9ct curr5t4 ,if ! wat] issues s sl[ly z to m]ely keep ! surface moi/1 x is n call$ a spr+1 b seepage4 ,! spr+ f :i* wat] issues ) a /rong curr5t1 especially if x be upw>d1 is comp>able to a fl[+ well1 :ile ! spr+ f :i* wat] issues ) little =ce1 & )\t upw>d movem5t1 is comp>able to ! fl[ ( wat] into a common well4 ,spr+s (t5 issue f ! sides ( valleys 7,fig4 #bab71 ! bottoms ( :i* are bel[ gr\nd-wat] level4 ,!y are especially likely to issue at ! surface ( relatively imp]vi\s lay]s1 & :]e ! valley slopes cut jo9ts1 por\s b$s1 or o!r /ructures :i* all[ free fl[ ( gr\nd-wat]4 ,illu/ration3 ,fig4 #bab4--;,diagram illu/rat+ positions1 a & b1 favorable = spr+s4 ,spr+s are classifi$ 9 v>i\s ways1 & ^! sev]al classifications sugge/ *>act]i/ics wor?y ( note4 ,!y are sometimes said to be deep & %all[4 ,! 8deep0 spr+1 z ! t]m is ord9>ily us$1 is "o :i* issues ) great =ce1 & ) some?+ ( upw>d movem5t1 & ! 8%all[0 spr+1 "o :i* issues ) little =ce1 & )\t upw>d movem5t2 b ! spr+ :i* issues ) =ce is n necess>ily deep1 nor is ! "o :i* issues ) little =ce necess>ily %all[4 ,! idea involv$ 9 ?is gr\p+ w\ld be bett] express$ by /rong & feeble4 ,spr+s are also classifi$ z cold & !rmal1 ! latt] t]m mean+ simply t ! temp]ature is su* z to make ! spr+s seem w>m or hot4 ,! temp]ature ( !rmal spr+s ranges up to ! boil+-po9t ( wat]4 ,betwe5 deep spr+s & %all[ ones1 & betwe5 cold spr+s & !rmal1 respectively1 !re is no %>p l9e ( dem>kation4 ,aga91 "s spr+s are cont9u\s 9 _! fl[1 :ile o!rs are int]mitt5t4 ,mo/ int]mitt5t spr+s fl[ aft] p]iods ( precipitation1 b dry up dur+ dr\ghts 7see p4 #bjb74 ,spr+s are also classifi$ z m9]al & common4 ,m9]al spr+s1 9 ! popul> s5se ( ! t]m1 are ( two types3 7#a7 ,^? :i* conta9 an unusual am\nt ( m9]al matt]1 & 7#b7 ^? :i* conta9 "s unusual m9]al4 ,spr+s are especially likely to be call$ m9]al if ! sub/ances :i* !y conta91 h1 or are suppos$ to h1 "s m$ic9al prop]ty4 ,all spr+s :i* are n 8m9]al0 are 8common40 ,?is classification is n altoge!r rational1 = all spr+s conta9 m or less m9]al matt]1 & _m spr+s :i* are 8common10 conta9 m m9]al matt] ?an "s spr+s t are 8m9]al40 ,m9]al spr+s are !mselves classifi$ accord+ to ! k9d & am\nt ( m9]al matt] !y conta94 ,?us sal9e spr+s conta9 salt2 sulphur spr+s conta9 comp\nds 7especially gase\s7 ( sulphur2 *alybeate spr+s conta9 iron comp\nds1 especially ! sulphate2 calc>e\s spr+s conta9 abundant lime c>bonate1 etc4 ,^! v>i\s m9]al sub/ances are extract$ f ! rock1 sometimes by simple solution1 & sometimes by solution result+ f o!r *emical *ange4 ,! salt ( sal9e spr+s is usually extract$ f b$s ( salt b5ea? ! surface4 ,lime c>bonate1 "o ( ! commone/ sub/ances 9 solution 9 gr\nd-wat]1 is dissolv$ f lime/one1 or d]iv$ by *emical *ange f rocks conta9+ o!r calcium comp\nds4 ,?us lime feldsp>s1 by c>bonation1 give rise to lime c>bonate4 ,! *alybeate wat]s (t5 arise f ! oxidation ( iron sulphide1 a m9]al :i* is common 9 _m s$im5t>y rocks4 ,! iron sulphate is itself subject to *ange 9 ! pres5ce ( ! ubiquit\s lime c>bonate4 ,f ?is *ange iron c>bonate results1 & ?is is usually quickly alt]$ to iron oxide1 :i*1 be+ relatively insoluble1 is precipitat$4 ,ab\t *alybeate spr+s1 !re=e1 iron oxide is frequ5tly be+ deposit$4 ,m$ic9al spr+s are ^? :i* conta9 "s sub/ance or sub/ances :i* h1 or are suppos$ to h1 curative prop]ties4 ,m9]al matt] 9 solution4--,! numb] & v>iety ( m9]al sub/ances 9 spr+ wat] is v great1 & ! am\nt ( solid matt] 9 solution v>ies widely4 ,"s ( ! hot spr+s ( ! ,yell[/one ,p>k conta9 ne>ly ?ree grams 7#b4hgcc7 ( m9]al matt] p] kilogram4#ajh ,! composition ( v>i\s spr+ & well wat]s is %[n 9 ! accompany+ table1 :i* gives "s idea ( ! range ( m9]al sub/ances commonly 9 solution 9 gr\nd-wat]4 ,geys]s4--,geys]s are int]mitt5tly eruptive hot spr+s4 ,!y occur only 9 volcanic regions 7pa/ or pres5t7 & 9 b few ( !m4 ,active geys]s are virtually conf9$ to ! ,yell[/one ,p>k & ,icel&1 ?\gh !y =m]ly exi/$ at o!r places4 ,^? ( ,new ,zeal& h b rec5tly become ext9ct4 ,! great geys] region ( ! _w is ! ,yell[/one ,p>k1 :]e !re are said to be m ?an sixty active geys]s4 ,! cause ( ! eruption is /eam4 ,! surface-wat] s9ks d[n until1 at "s unkn[n dep?1 x comes into contact ) rock suffici5tly hot to boil x4 ,! s\rce ( ! heat is n op5 to inspection1 b x is believ$ to be ! uncool$ "p ( an extrusive lava fl[1 or ( an intrusive lava mass4 ,f :at 0 said on pp4 #baf & #bag x is cle> t geys]s d n h _! orig9 9 wat] :i* s9ks d[n to ! zone ( great heat1 :]e ! increm5t ( heat is normal4 ,! wat] ( a geys] issues ?r\gh a tube ( unkn[n l5g?4 ,:e!r ! tube is op5 d[n to ! s\rce ( ! heat is n det]m9able1 b wat] f su* a s\rce f9ds its way to ! tube4 ,wat] may ent] ! tube f all sides & at v>i\s levels f top to bottom4 ,! heat+ may prec$e or foll[ its entrance into ! tube1 or bo?4 ,s f> z ! wat] is heat$ aft] x ent]s ! tube1 ! po9t ( mo/ rapid heat+ may be at ! bottom ( ! tube or at "s po9t above4 ,if ! temp]ature ( ! s\rce ( heat 7 high en\gh to conv]t ! desc5d+ wat] into /eam z fa/ z x ent]s ! tube1 ! /eam w\ld escape cont9u\sly1 ?\gh !re w\ld be no geys]2 b if ! rock is only hot en\gh to br+ ! wat] to ! boil+-po9t aft] "s lapse ( "t1 & aft] "s wat] has accumulat$1 an eruption is possible4 ,,analyses ,,( ,,am]ican ,,spr+-,,wat]s4#aji ,r$uc$ to ,p>ts p] #ajjj by ,dr ,h4 ,j4 ,van ,hoes54 ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ----------------------- ,wat]s ,artesian well ,artesian well ,artesian well#aaj ,manit\ ,spr+ ,opal ,spr+ ,sulphur ,spr+ ,hot ,spr+ ,hot ,spr+ ,boil+ ,spr+ ,w>m ,spr+ 8,glaci] ,sp\t+ ,spr+0 ,location ,lex+ton1 ,ky4 ,s>atoga1 ,n4 ,y4 ,%eboygan1 ,wis4 ,manit\1 ,col4 ,yell[/one ,los ,angeles1 ,cal4 ,hot ,sp4 ,/ation1 ,w>d's ,ran*1 ,%aff]'s ,ran*1 ,w>m ,spr+ ,/a4 ,national ,p>k ,c4 ,p4 ,r4 ,r4 base ( ,granite ,honey ,lake ,b4 ,b4 ,r4 ,mts41 ,nev4 ,valley1 ,cal4 ,mono ,bas9 ,date #ahgb ,feb4 #ahgf ,analy/ ,r4 ,pet]s ,f4 ,a4 ,cairns & ,c4 ,f4 ,*&l] ,osc> ,loew ,h4 ,leffman ,osc> ,loew ,t4 ,m4 ,*at>d ,t4 ,m4 ,*at>d ,t4 ,m4 ,*at>d ,t4 ,m4 ,*at>d ,c4 ,f4 ,*&l] ,ref]5ces ,ky4 ,geol4 ,surv41 ,am4 ,*emi/1 ,nov4 ,am4 ,*emi/1 #ahgf1 ,u4 ,s4 ,g4 ,s4 ,w41 ,u4,s4 ,geol4 ,geog4 ,an4 ,rep4 ,u4 ,s4 ,g4 ,ante1 p4 #di ,ante1 p4 #ec ,ante1 p4 #ea ,bullet9 ,no4 #i1 ,u4 ,n4 ,s41 ,vol4 ,v1 p4 #ahgb1 p4 #afd p4 #cgj #ajj? ,m44 ,vol4 ,surv4 ,id41 ,wyo4 ,s4 ,w41 #ajj? ,m41 ,s4 ,geol4 ,survey1 #ahi ,,iii1 p4 #fah ,t]41 #ahgh1 p4 #cic #ahgf1 p4 #aie p4 #bg ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ----------------------- ,sodium1 ,na 4#jibbg #d4gbfdj #b4jcih 4#deafd 4#dfae 4#ajdbd 4#ggdc 4#ceed 4#cjdj 4#faaf ,potassium1 ,k 4#jjiai 4#cehjf 4#abhe 4#jeihj 444444 ,trace 4#jffi 4#jaia 4#jjid 4#jfcj ,calcium1 ,ca 4#jbacf 4#idjej #a4jgci 4#dddjj 4#jcdd 4#jcje 4#jcfg 4#jaba 4#jehi 4#ejfjjaaa ,magnesium1 ,mg 4#jahje 4#ecdgj 4#bceb 4#jehfj 444444 4#jjaj 4#jjcd 4#jjjd 4#jfjd ,b>ium1 ,ba 444444 4#jahdh ,trace ,/rontium1 ,sr ,trace#aab 4#jjjeg ,li?ium1 ,li ,trace 4#jajgh 4#jjjc 4#jjjci 444444 ,trace ,iron1 ,fe ,trace#aac 4#jjcda 4#jjbg ,trace#aad 444444 ,trace ,manganese1 ,mn 444444 444444 4#jjji 444444 444444 ,trace ,*lor9e1 ,cl 4#jgdfe #g4dgdjj #d4bgcj 4#bdhej 4#gdif ,trace#aae 4#ifig 4#bcif 4#bjgj 4#bbgb ,brom9e1 ,br 4#jdffa 4#jjbe ,iod9e1 ,i 4#jjjfj ,trace ,fluor9e1 ,fl 444444 ,trace#aaf ,c>bonic acid1 ,,co 4#abafj #e4hbfjc 4#agib #a4aajja 444444 4#jceaf 444444 ,trace 444444 4#eghg ,sulphuric acid1 ,h,,s 4#jcbah 4#jjbcd #b4jcah 4#bjfif 4#jcbe 4#afadj 4#ceee 4#cija 4#cdib 4#caca ,phosphoric acid1 ,h,,po ,trace 4#jjjje 4#jjjd 444444 444444 ,trace ,boracic acid1 ,h,,bo ,trace ,trace ,alum9a1 ,al,o 444444 4#jjggj 4#jjbb 444444 444444 ,trace 4#jjaj 444444 444444 4#jjah ,silica1 ,si,o 4#jjidj 4#jaagd 4#jjhj 4#jbjaj 4#gfhj ,trace 4#bghh 4#aacf 4#acaj 4#abbj ,hydrog5 9 bic>bonates1 ,h 444444 4#jigac 4#jjcj ,organic sub/ances ,trace ,trace ,trace 444444 444444 ,trace ,oxyg51 ,o 444444 444444 444444 444444 444444 444444 4#jaidaag 4#jbeeaag 4#jjhjaag 4#jcbeaag ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- --------------------------------- 4#cghgj #bj4jeiaj #i4ihad #b4fjjjj #b4jdfj 4#hjfhj #b4diec #a4ahcd #a4jbaa #b4jfib ,c>bonic acid1 ,,co 444444 #b4jaeaah 444444 444444 444444 ,9 excess ,trace ,sulphurett$ hydrog51 ,h,s 444444 444444 444444 444444 444444 #j4ejjj ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ----------------------- ,illu/ration3 ,fig4 #bac4--8,old ,fai?ful0 9 eruption4 ,! exact sequ5ce ( ev5ts :i* leads up to an eruption is n kn[n1 b a def9ite conception ( ! pr9ciples involv$ may p]haps be secur$ by a def9ite case4 ,suppose a geys]-tube fill$ ) wat]1 & heat$ at its l[] end4 ,z ! wat] is heat$ bel[1 convection t5ds to di/ribute ! heat ?r\gh\t ! column ( wat] above4 ,if convection 7 free1 & ! tube %ort1 ! result w\ld be a boil+ spr+2 b if ! tube is long1 & especially if convection is imp$$1 ! wat] at "s level bel[ ! surface may be br\ght to ! boil+-po9t e>li] ?an t at ! top4 ,"u ^! circum/ances if ev5 a little wat] 9 ! l[] "p ( ! tube is conv]t$ into /eam1 ! /eam w raise ! column ( wat] above1 & x w ov]fl[4 ,! ov]fl[ relieves ! pressure on all p>ts ( ! column ( wat] bel[ ! surface4 ,if be=e ! ov]fl[ !re 0 any consid]able volume ( wat] ess5tially ready to boil1 ! relief ( pressure foll[+ ! ov]fl[ might all[ x to be conv]t$ into /eam sudd5ly1 & ! sudd5 conv]sion ( any consid]able quantity ( wat] into /eam w\ld cause ! eruption ( all ! wat] above x 7,figs4 #bac & #bad74 ,! height to :i* ! wat] w\ld be ?r[n w\ld dep5d ^u ! am\nt ( /eam1 ! size & /raightness ( ! tube1 etc4 ,x is cle> t ev]y?+ :i* imp$es convection 9 ! geys] tube w ha/5 ! p]iod ( eruption1 s9ce imp$$ circulation w h ! effect ( hold+ ! heat d[n1 & s ( br++ ! wat] at "s level bel[ ! top m quickly to ! boil+-po9t4 ,x foll[s t any?+ :i* *okes up ! tube1 or :i* increases ! viscosity ( ! wat]1 or its surface t5sion1 w\ld ha/5 an eruption4#aai ,geys]s (t5 build up crat]-l bas9s or cones 7,figs4 #bad to #bag7 ab\t !mselves1 ! cone be+ ( mat]ial deposit$ f solution4 ,9 ! ,yell[/one ,p>k ! precipitation ( ! matt] 9 solution 7*iefly silica7 is p>tly due to cool+ & p>tly to ! alg :i* ab\nd ev5 9 ! boil+ wat]1 & ! brilliant colors ( ! deposits ab\t ! spr+s are attributable to ^! plants4 ,:5 ! wat] f any geys] or hot spr+ ceases to fl[ ! plants die & ! colors disappe>4 ,! details ( ! surface ( ! deposits ab\t geys]s & hot spr+s are (t5 complicat$1 & frequ5tly v beautiful 7,fig4 #bah74 ,illu/ration3 ,fig4 #bad4--8;,giant0 ,geys]1 ,yell[/one ,p>k1 9 eruption4 ,%[s also ! cone4 7,w9eman47 ,illu/ration3 ,fig4 #bae4--;,cone 7or crat]7 ( ,ca/le ,geys]1 ,yell[/one ,p>k4 7,detroit ,photo4 ,co47 ,illu/ration3 ,fig4 #baf4--;,cone 7or crat]7 ( ,grotto ,geys]1 ,yell[/one ,p>k4 7,detroit ,photo4 ,co47 ,illu/ration3 ,fig4 #bag4--;,cone ( ,giant ,geys]1 ,yell[/one ,p>k4 7,w9eman47 ,! heat+ ( geys] & hot-spr+ wat] mu/ cool ! lava or o!r s\rce ( heat bel[4 ,z ?is takes place1 ! "t betwe5 eruptions becomes long] & long]4 ,9 ! c\rse ( "t1 !re=e1 ! geys] mu/ cease to be eruptive1 & :5 ?is *ange is br\ght ab\t ! geys] becomes a hot spr+4 ,)9 hi/oric times sev]al geys]s h ceas$ to erupt & new ones h be5 develop$4 ,9 ! ,yell[/one ,p>k1 :]e !re are said to be some?+ l #cjjj v5ts ( all sorts1 hot spr+s :i* are n eruptive greatly outnumb] ! geys]s4 ,f _m ( ! v5ts b little /eam issues1 & f "s1 little else4 ,illu/ration3 ,fig4 #bah4--;,hot spr+s deposits4 ,t]races ( ,mammo? ,hot ,spr+s1 ,yell[/one ,p>k4 ,a few geys]s h some:at def9ite p]iods ( eruption4 ,( su* 8,old ,fai?ful0 is ! type2 b ev5 ?is geys]1 :i* =m]ly erupt$ at regul> int]vals ( ab\t an h\r1 is los+ ! reputation on :i* its "n is bas$4 ,n only is its p]iod ( eruption l5g!n+1 b x is becom+ irregul>1 & ! irregul>ity appe>s to be increas+4 ,9 ! %ort "t dur+ :i* ?is geys] has be5 "u obs]vation its p]iod has *ang$ f a regul> "o ( sixty m9utes1 or a little less1 to an irregul> "o ( sev5ty to n9ety m9utes4 ,9 ! case ( "s geys]s ye>s elapse betwe5 eruptions1 & 9 "s ! date ( ! la/ eruption is s di/ant t x is unc]ta9 :e!r ! v5t %\ld be look$ ^u z a geys] or m]ely a hot spr+4 ,9 ! ,yell[/one ,p>k#abj ! geys]s are ma9ly 9 ! bottoms ( valleys 7,fig4 #bai71 b ! deposits *>act]i/ic ( geys]s are f\nd 9 n a few places well above ! pres5t bottoms4 ,^! deposits record ! fact t 9 e>li] times ! geys]s 7 at high] levels ?an n[4 ,x is probable t !y h be51 at all /ages 9 _! hi/ory1 ne> ! bottoms ( ! valleys1 & t1 z ! valleys h be5 deep5$ ! gr\nd-wat] has f\nd l[] & l[] po9ts ( issue4 ,9 ?is respect ! geys]s h probably _h ! same hi/ory z o!r spr+s4 ,illu/ration3 ,fig4 #bai4--;,hot spr+s & geys]s4 ,norris ,geys] bas91 ,yell[/one ,p>k4 ,unless new intrusions ( lava occur1 or unless heat is o!rwise r5ew$ at ! prop] po9ts1 x is probable t all exi/+ geys]s w become ext9ct )9 a "t :i* is1 geologically1 %ort4 ,new geys] regions may1 h[ev]1 develop z old ones disappe>4 ,artesian wells4--,orig9ally ! t]ms artesian wells & fl[+ wells 7 synonym\s2 b at ! pres5t "t any notably deep well is call$ artesian1 especially if x desc5ds to consid]able dep?s bel[ ! mantle rock4 ,! artesian well :i* does n fl[1 does n diff] f common wells 9 pr9ciple2 b be+ deep]1 ! wat] :i* x af=ds is (t5 m ?or\ghly filt]$ & frequ5tly m highly m9]aliz$ ?an t ( o!r wells4 ,! fl[+ well is really a gu%+ spr+1 ! op5+ ( :i* 0 made by man4 ,fl[+ wells#aba dep5d ^u c]ta9 relations ( rock /ructure1 wat] supply1 & elevation4 ,g5]ally speak+ a fl[+ well is possible 9 any place und]la9 by any consid]able b$ ( por\s rock1 if su* rock outcrops at a suffici5tly high] level 9 a region ( adequate ra9fall1 & is cov]$ by a lay] or b$ ( imp]vi\s1 or relatively imp]vi\s rock4 ,?is /atem5t involves f\r conditions1 all ( :i* are illu/rat$ by ,fig4 #aii1 :]e a is ! b$ ( por\s rock4 ,x is n necess>y t ! b$s ( rock =m a /ructural bas91 nor is x usually necess>y to take acc\nt ( ! "* ( ! rock b5ea? ! por\s b$ :i* conta9s ! wat]4 ,! b$ ( por\s rock is ! 8res]voir0 ( ! fl[+ well4 ,=mations ( s& or s&/one1 & ( gravel or conglom]ate1 mo/ commonly s]ve z ! res]voirs4 ,9 ord] t x may conta9 abundant wat] x mu/ h "s ?ickness1 & its outcropp+ edge mu/ be s situat$ t ! wat] may ent] freely & be repl5i%$1 *iefly by ra91 z ! wat] fl[s out at ! well4 ,a relatively imp]vi\s lay] ( rock above ! res]voir 7b1 ,fig4 #aii7 is mo/ important2 o!rwise ! wat] 9 ! res]voir w leak out1 & !re w be little or no 8head0 at ! well site4 ,?us if ! rock ov]ly+ /ratum a 7,fig4 #aii7 7 badly brok51 ! fractures ext5d+ up to ! surface1 ! conditions w\ld be unfavorable = fl[+ wells4 ,"u su* conditions1 wells 9 ! positions ( ^? %[n 9 ,fig4 #aii might get abundant wat]1 b !y w\ld n be likely to fl[4 ,if ! /ratum next bel[ ! res]voir is n imp]vi\s1 "s l[] "o probably is4 ,no lay] ( rock is m imp]vi\s ?an "o :i* is full ( wat]1 & ! sub/ructure ( any b$ :i* might s]ve z a res]voir is usually full ( wat]1 ev5 if ! rock be por\s4 ,if ! outcrop ( ! res]voir be notably above ! site ( ! well1 & if x be kept full by frequ5t ra9s1 ! 8head0 w be /rong1 ?\gh ! wat] at ! well w n rise to ! level ( ! outcrop ( ! res]voir4 ,exp]i5ce has %[n t an all[ance ( ab\t "o foot p] mile ( subt]ranean fl[ %\ld be made4 ,?us if ! site ( ! well be #ajj miles f ! outcrop ( ! wat]-be>+ /ratum1 & #bjj feet bel[ x1 ! wat] w rise some?+ l #ajj feet above ! surface at ! well4 ,?is rule is1 h[ev]1 n applicable ev]y:]e4 ,! failure ( ! wat] to rise to ! level ( its head is due to ! adhesion & ! friction ( fl[ ?r\gh ! rock4 ,! m por\s ! rock ! less ! r$uction ( head by friction4 ,! height ( ! fl[ is also influ5c$ by ! numb] ( wells draw+ on ! same res]voir1 on ! degree ( imp]vi\sness ( ! conf9+ b$ above1 etc4 ,fl[+ wells1 (t5 relatively %all[1 are frequ5tly obta9$ f unconsolidat$ drift4 ,"s su* relations z sugge/$ by ,fig4 #bbj w\ld af=d ! conditions = fl[+ wells 9 su* a =mation4 ,illu/ration3 ,fig4 #bbj4--;,figure illu/rat+ ! pr9ciple ( artesian wells 9 drift4 ,,*apt] ,v4 ,,! ,,"w ,,( ,,sn[ ,,& ,,ice4 ,a "p ( ! atmosph]ic precipitation falls z sn[1 & ?is1 l ! ra91 does its appropriate "w 9 degrad+ ! l&4 ,ov] ! l>g] "p ( ! l& surface ! sn[ ( ! w9t] does n endure ?r\gh ! succe$+ summ]1 & :5 x melts x foll[s ! same c\rse z ! precipitation :i* falls z ra92 b 9 cold regions :]e ! fall ( sn[ is heavy "s ( x rema9s unmelt$ & con/itutes p]5nial sn[-fields4 ,,sn[- ,,& ,,ice-,,fields4 ,sn[-fields4--,m\nta9 heights & pol> l&s are ! mo/ common habitats ( sn[-fields1 ?\gh !y are n conf9$ to ^! situations4 ,9 ,nor? ,am]ica !re are num]\s small sn[-fields 9 ! we/]n m\nta9s1 f ,mexico on ! s\? to ,alaska on ! nor?1 _! numb] & size increas+ 9 ! latt] direction4 ,9 ! ,unit$ ,/ates !re are few sn[-fields s\? ( ! p>allel ( #cf #cj1 & mo/ ( ! _m hundr$s nor? ( t latitude 7exclud+ ,alaska7 are small 7,pl4 ,,xviii1 ,fig4 #a1 ,wa%+ton1 lat4 #dh #e1 long4 #aba #e2 ,fig4 #b1 lat4 #da #be1 long4 #abb #ab4 ,f ,glaci] ,peak & ,%a/a ,special ,quadrangles1 ,u4 ,s4 ,geol4 ,surv474 ,f>!r nor?1 especially 9 ,alaska1 ! sn[-fields ( ! we/]n m\nta9s atta9 mu* great] size4 ,9 ,europe sn[-fields comp>able to ^? ( ! nor?we/]n "p ( ! ,unit$ ,/ates & ,briti% ,columbia occur 9 ! ,alps 7,fig4 #bba71 ! ,pyr5ees1 ! ,caucasus1 & ! ,sc&9avian m\nta9s4 ,9 ,asia sn[-fields occur 9 ! ,himalayas & 9 _m ( ! high m\nta9s f>!r nor?1 f ,turke/an on ! s\?we/ ne>ly to ! coa/ on ! nor!a/4 ,9 ,s\? ,am]ica !re are sn[-fields ( small size ev5 9 equatorial latitudes1 & f>!r s\? 9 ! ,*ilean ,&es !re are "s ( consid]able size4 ,small sn[-fields occur on ! highe/ peaks ( tropical ,africa1 & 9 ! m\nta9s ( ,new ,zeal&4 ,= reasons :i* w appe> lat]1 mu* ( e consid]able sn[-field is really ice4 ,9 addition to ^! limit$ fields ( sn[ 9 m\nta9 regions1 !re are fields ( mu* great] ext5t cov]+ wide expanses ( pla9 & plateau 9 ! pol> regions4 ,! great] "p ( ! isl& ( ,gre5l& is cov]$ ) a s+le field ( ice & sn[1 ! size ( :i* is v>i\sly e/imat$ at #cjj1jjj to #djj1jjj squ>e miles 7,fig4 #bbb7--;an area #djj to #fjj times z l>ge z ! sn[-&-ice-cov]$ area ( ,switz]l&4 ,num]\s isl&s to ! we/ ( ,nor? ,gre5l& are also p>tly cov]$ ) sn[1 ! areas ( ! sn[-fields f> exce$+ ^? ( mo/ m\nta9 regions4 ,9 ,ant>ctica !re is believ$ to be a /ill l>g] field1 ! l>ge/ ( ! e>?4 ,its area is n ev5 approximately kn[n1 b su* data z are at h& indicate t x may h an ext5t ( #c1jjj1jjj or #d1jjj1jjj squ>e miles4 ,illu/ration3 ,fig4 #bba4--;,an alp9e sn[-field4 ,illu/ration3 ,fig4 #bbb4--,map ( ,gre5l&4 ,! bord]s only are free f ice4 7,/iel]47 ,! only condition necess>y = a sn[-field is an excess ( sn[fall ov] sn[ wa/e4 ,! l[] edge ( a sn[-field1 ! sn[-l9e1 is dep5d5t *iefly on temp]ature & sn[fall4 ,9 g5]al x does n dep>t mu* f ! summ] iso!rm ( #cb1 ?\gh x may be well above ?is iso!rm :]e ! sn[fall is light4 ,t ! sn[-l9e is n a function ( temp]ature only is %[n by its position 9 v>i\s places4 ,9 ! equatorial portion ( ! ,&es1 = example1 ! sn[-l9e has an altitude ( ab\t #af1jjj feet on ! ea/ side ( ! m\nta9s1 :]e ! precipitation is heavi]1 & ( ab\t #ah1ejj feet on ! we/ side1 :]e x is light]4 ,= ! same reason ! sn[-l9e 9 ! ,himalayas is #cjjj or #djjj feet l[] on ! s\? side ?an on ! nor?4 ,:ile 9 equatorial regions ! sn[-l9e has an altitude ( #ae1jjj to #ah1jjj feet1 x approa*es or ev5 rea*es sea-level 9 ! latitude ( ,ant>ctica & ,nor? ,gre5l&4 ,9 int]m$iate latitudes x has an int]m$iate position4 ,:ile temp]ature & sn[fall are ! mo/ important factors controll+ ! position ( ! sn[-l9e1 bo? humidity & ! movem5ts ( ! air are ( "s importance1 s9ce bo? affect ! rate ( evaporation ( sn[ & ice4 ,! passage ( sn[ into nv & ice4--,! sn[ does n lie on ! surface long be=e x und]goes obvi\s *ange4 ,! light flakes soon beg9 to be trans=m$ into granules1 & ! sn[ becomes 8co>se-gra9$40 ,! granul> "*1 s pron\nc$ 9 ! sn[ ( ! la/ banks :i* rema9 9 ! spr+ 9 temp]ate latitudes1 is ev5 m di/9ct 9 p]5nial sn[-fields1 ei!r at ! surface or j b5ea? x4 ,?is granul> sn[ is call$ nv1 or firn4 ,/ill deep] b5ea? ! surface1 :]e ! ?ickness ( ! sn[ is great1 ! nv becomes m compact & f9ally coh]5t1 & grades into por\s ice4 ,?is gradation is accompli%$ at no great dep?1 ?\gh ! ?icknesses ( sn[ & nv are by no means con/ant4 ,/ructure ( ! ice4--,ice =m$ b5ea? a sn[-field is 9 "s s5se /ratifi$4 ,x is made up ( successive falls ( sn[ :i* t5d to reta9 ! =m ( lay]s4 ,?is foll[s f two or ?ree conditions4 ,! sn[ ( "o season1 or ( "o p]iod ( precipitation1 may h be5 consid]ably *ang$ be=e ! succe$+ fall ( sn[4 ,s also ! surface ( ! sn[-field at ! end ( ! melt+ season is (t5 cov]$ ) a visible am\nt ( e>?y matt]1 "s ( :i* 0 bl[n up & dropp$ on ! surface dur+ ! melt+ season1 & "s ( :i* 0 conc5trat$ 9 t position by ! melt+ ( ! sn[ 9 :i* x 0 orig9ally imb$d$4 ,! am\nt ( e>?y matt] is (t5 suffici5t to def9e sn[s ( successive ye>s1 or p]haps ( m9or p]iods ( precipitation1 & makes di/9ct ! /ratification :i* w\ld o!rwise rema9 obscure4 ,! sn[fall ( successive ye>s has be5 e/imat$ by ?is means#abb :]e ! sn[ is expos$ 9 crevices 9 ! sn[-field4 ,9 addition to its rude /ratification1 ! ice ( ! deep] portions (t5 acquires a /rati=m /ructure :i* may p]haps be/ be call$ foliation to di/+ui% x f ! /ratification :i* arises f deposition4 ,! foliation appe>s to result ma9ly f ! %e>+ ( "o "p ov] ano!r 9 ! c\rse ( ! movem5ts to :i* ! ice is subject$1 z w be illu/rat$ pres5tly4 ,texture4--,! ice d]iv$ f ! sn[ is =m$ ( int]lock+ cry/all9e gra9s4 ,! cry/all9e "* is pres5t f ! beg9n+1 = x is assum$ by ! sn[flakes :5 !y =m1 & ! subsequ5t *anges seem only to modify ! orig9al cry/als by build+ up "s & de/roy+ o!rs4 ,by ! "t ! sn[ is conv]t$ into nv1 ! granules h become co>se1 & :]ev] ! ice d]iv$ f ! nv has be5 exam9$1 ! granul> cry/all9e texture is pres5t4 ,! individual cry/als 9 ! ice are usually l>g] ?an ^? ( ! nv1 & m closely gr[n toge!r4 ,9 ! fre% unexpos$ ice ! cry/als are s intimately int]lock$ t !y are n readily se5 except "u a pol>iz+ microscope1 b :5 ! ice has be5 honeycomb$ by p>tial melt+1 ! granules become p>tially sep>at$ & may be easily se54 ,fig4 #bbc %[s quantities ( !m :i* h be5 wa%$ d[n f ! surface1 & dispos$ z cones at its base4 ,:ile a giv5 mass ( sn[ 9 a great sn[- & ice-field _c be foll[$ consecutively ?r\gh its :ole hi/ory1 yet s9ce 7#a7 ! granul> texture is pron\nc$ 9 ! nv /age :]e ! granules %[ evid5ces ( gr[?1 & s9ce 7#b7 ! same texture is also pron\nc$ 9 ! la/ /ages ( ! ice :5 x is und]go+ dissolution1 z well z at all obs]v$ int]m$iate /ages1 & s9ce 7#c7 ! cry/als are1 on ! av]age1 l>g] 9 proportion to ! lat5ess ( ! /age ( _! hi/ory1 :ile 7#d7 exp]im5t has %[n t granules gr[ "u ! conditions :i* exi/ 9 sn[-fields1 & 7#e7 t !y p]si/ "u v consid]able pressure1 x is legitimate to assume t a granul> cry/all9e condition p]si/s ?r\gh\t all /ages1 & is a feature ( progressive gr[?4 ,illu/ration3 ,fig4 #bbc4--;,figure %[+ cones ( granules ( ice :i* h be5 wa%$ d[n ! front ( ! glaci] by /reamlets1 & accumulat$ aft] ! mann] ( talus or alluvial cones4 ,nor? ,gre5l&4 ,inauguration ( movem5t4--,ev5tually ! increase 9 dep? ( sn[ & ice 9 a sn[-field gives rise to motion4 ,! exact nature ( ! motion has n yet be5 demon/rat$ to ! satisfaction ( all inve/igators4 ,brittle & resi/ant z ice seems1 x exhibits1 "u prop] conditions1 "s ( ! outw>d *>act]i/ics ( a pla/ic sub/ance4 ,?us x may be made to *ange its =m1 & may ev5 be m\ld$ into almo/ any desir$ %ape if c>efully subject$ to suffici5t pressure1 /eadily appli$ ?r\gh long int]vals ( "t4#abc ,^! *anges may be br\ght ab\t )\t visible fracture1 & h be5 ?\ght to po9t to a visc\s condition ( ! ice4 ,!re is mu* reason1 h[ev]1 z w be se5 lat]1 to "q ?is int]pretation ( ! ultimate nature ( ! movem5t4 ,:atev] ?is may be1 ! mass result ( ! movem5t 9 a field ( ice is comp>able1 9 a sup]ficial way at lea/1 to t :i* w\ld be br\ght ab\t if ! ice 7 capable ( mov+ l a visc\s liquid1 ! motion tak+ place ) extreme sl[ness4 ,?is sl[ motion ( ice 9 an ice-field is glaci] motion1 & ice ?us mov+ is glaci] ice4 ,illu/ration3 ,fig4 #bbd4--;,ice-caps ( small size4 ,! figure also %[s "s valley glaci]s ext5d+ out f ! ma9 ice-%eet & f ! local ice-caps4 ,a portion ( ! ,nor? ,gre5l& coa/1 nor? ( ,+lefield ,gulf4 ,lat4 ab\t #gh4 7,pe>y47 ,illu/ration3 ,fig4 #bbe4--,small ice-caps 9 ! nor?we/]n "p ( ,icel&4 7,?oradds5's geological map ( ,icel&47 ,illu/ration3 ,fig4 #bbf4--;,a glacial lobe1 midway betwe5 an ice-cap & a valley glaci]4 ,a protrusion f a local ice-cap ea/ ( ,cape ,york1 ,gre5l&4 ,if bo? ! surface on :i* ! ice-%eet develops & its surr\nd+s be ess5tially plane1 z may happ5 9 high latitudes1 & if ! sn[- & ice-field be symmetrical 9 %ape1 ! outw>d movem5t w be approximately equal 9 all directions1 & ! area cov]$ by ! spread+ ice-field w rema9 m or less circul>4 ,if ! ice-field re/s on a /eeply incl9$ surface1 l a m\nta9 slope1 ! movem5t becomes "o-sid$ 9 con=mity to ! slope4 ,if ! surface1 o!rwise plane1 be affect$ by valleys p>allel to ! direction ( movem5t1 ! ice 9 ! valleys w be deep] ?an t on ! divides betwe5 !m1 & its movem5t /rong]4 ,9 ! valleys1 !re=e1 ! ice w advance f>!r ?an else:]e be=e be+ melt$1 & ! outl9e ( ! ice w become lobate1 ! lobes occupy+ ! depressions4 ,^! g5]al relations are %[n 9 ,figs4 #bbd & #bbe4 ,if ! depressions be wide & %all[1 ! lobes w be broad & %ort 7,fig4 #bbf72 if ! depressions be n>r[ & deep1 ! lobes w be relatively n>r[ & long4 ,if ! sn[ & ice re/ on a surface consi/+ *iefly ( /eep valleys & %>p ridges1 z is common on m\nta9 slopes1 ! sn[ & ice are *iefly ga!r$ 9 ! valleys1 & take a l9e> =m4 ,,types ,,( ,,glaci]s4 ,^! diff]5t =ms give rise to diff]5t t]ms4 ,! ice :i* spreads ) "s approa* to equality 9 all directions f a c5t] is a glaci]1 is inde$ ! type ( ! greate/ glaci]s1 b is commonly call$ an ice-cap4 ,! same "n is appli$ to any glaci] 9 :i* !re is movem5t 9 all directions f ! c5t]1 ev5 ?\gh its %ape dep>ts widely f a circle4 ,! glaci] cov]+ ! l>g] "p ( ,gre5l& 7,fig4 #bbb7 is a good example ( a l>ge ice-cap1 & ! glaci]s on "s ( ! flat-topp$ p59sul> promontories ( ! same isl& are good examples ( small ones 7,fig4 #bbd74 ,if ice-caps cov] a l>ge "p ( a cont95t1 z "s ( ^? ( ! pa/ h done1 !y are (t5 call$ cont95tal glaci]s4 ,illu/ration3 ,fig4 #bbg4--;,*>act]i/ic end ( a ,nor? ,gre5l& 7,bryant7 glaci]4 ,illu/ration3 ,fig4 #bbh4--,! ,rhne glaci]4 7,reid47 ,illu/ration3 ,fig4 #bbi4--;,*>act]i/ic end ( a ,nor? ,gre5l& glaci]4 ,nor? side ( ,h]b]t ,isl&1 ,+lefield ,gulf4 ,illu/ration3 ,fig4 #bcj4--,! end ( an alp9e 7,=no1 ,switz]l&7 glaci]4 7,reid47 ,illu/ration3 ,fig4 #bca4--;,deploy+ end ( a ,nor? ,gre5l& glaci]4 ,:]e ice-caps are develop$ on plateaus ^: bord]s are tr5*$ by valleys1 ice-tongues f ! edge ( ! ice-cap (t5 ext5d d[n into ! valleys & give rise to "o type ( valley glaci] 7,figs4 #bbd & #bbg74 ,a second & m famili> type ( valley glaci] occupies m\nta9 valleys1 & is ! (fspr+ ( m\nta9 sn[-fields 7,fig4 #bbh74 ,! =m] are conf9$ *iefly to high latitudes1 & are di/+ui%$ z pol> or high-latitude glaci]s 7,figs4 #bbg & #bbi72 ! latt] are kn[n z alp9e glaci]s 7,figs4 #bbh & #bcj74 ,! end & side slopes ( pol> glaci]s are1 z a rule1 mu* /eep] ?an ^? ( alp9e glaci]s4 ,:5 a valley glaci] desc5ds ?r\gh its valley to ! pla9 beyond1 its end deploys1 =m+ a fan 7,fig4 #bca74 ,! deploy+ ends ( adjac5t glaci]s sometimes m]ge1 & ! result+ body ( ice con/itutes a pi$mont glaci] 7,fig4 #bcb74 ,at ! pres5t "t1 pi$mont glaci]s are conf9$ to high latitudes4 ,9 "s cases ! sn[-field t gives rise to a glaci] is re/rict$ to a relatively small depression 9 ! side ( a m\nta91 or 9 ! esc>pm5t ( a plateau4 ,9 su* cases ! sn[-field & glaci] are h>dly di/+ui%able1 & ! latt] desc5ds b little bel[ ! sn[-l9e4 ,9 _m cases x does n ev5 ent] ! n>r[ valley :i* leads out f ! depression occupi$ by ! sn[-field4 ,su* a glaci] is ne/l$ 9 ! face ( a cliff1 & may !re=e be call$ a cliff glaci]#abd 7,figs4 #bcc & #bcd74 ,! sn[-field ( a cliff glaci] is sometimes no m ?an a great sn[drift1 accumulat$ ?r\gh successive ye>s4 ,cliff glaci]s are (t5 z wide z long1 & are always small1 & betwe5 !m & valley glaci]s !re are all gradations 7,fig4 #bce74 ,occasionally ! end ( a valley glaci]1 or ! edge ( an ice-%eet rea*es a precipit\s cliff1 & ! end or edge ( ! ice breaks (f & accumulates l talus bel[4 ,! ice fragm5ts may !n aga9 become a coh]5t mass by regelation1 & ! :ole may resume motion4 ,su* a glaci] is call$ a recon/ruct$ glaci]4 ,! precipit\s cliffs ( ! ,gre5l& coa/ furni% illu/rations4 ,illu/ration3 ,fig4 #bcb4--,! ,malasp9a glaci]1 ,alaska2 ! be/ kn[n example ( a pi$mont glaci]4 7,russell47 ,illu/ration3 ,fig4 #bcc4--;,a cliff glaci]4 ,nor? ,gre5l& type4 ,nor? side ( ,h]b]t ,isl&1 ,+lefield ,gulf4 ,! l[] half ( ! :ite area is sn[1 & sn[ talus4 ,s also are ! :ite pat*es to ! "r4 ,! height ( ! cliff is p]haps #bjjj feet4 ,! wat] 9 ! =egr\nd is ! sea4 ,illu/ration3 ,fig4 #bcd4--;,*ancy glaci]2 a cliff glaci] ( ! ,montana type4 7,%ep>d47 ,( ! =ego+ types ( glaci]s1 ! ice-caps f> exce$ all o!rs bo? 9 size & importance1 :ile ! valley glaci]s out-rank1 9 ! same respects1 ! o!r types2 b s9ce ! valley glaci]s are ! mo/ famili> type1 ! g5]al ph5om5a ( glaci]s w be discuss$ ) prim>y ref]5ce to !m4 ,,! ,,g5]al ,,ph5om5a ,,( ,,glaci]s4#abe ,dim5sions4--,glaci]s :i* occupy valleys lead+ d[n f sn[-fields sometimes rea* ! upp] p>ts ( ! valleys only1 sometimes ext5d ?r\gh !m1 & sometimes pu% out on ! pla9 beyond4 ,9 l5g? !y range f a fraction ( a mile to _m miles1 & ?\gh _! wid? is usually mu* less ?an _! l5g?1 ! rev]se is sometimes ! case 7,figs4 #bcc1 #bcd1 & #bce74 ,_! ?ickness is usually measur$ by hundr$s ( feet r ?an by d5om9ations ( o!r ord]s1 b ! v>iation is great1 & exact measurem5ts are almo/ :olly want+4 ,! m9imum ?ickness is t necess>y to cause movem5t1 & ?is v>ies ) ! slope1 ! temp]ature1 & o!r conditions4 ,!re is also mu* v>iation 9 ! ?ickness 9 diff]5t p>ts ( a glaci]4 ,z a rule1 x is ?9ne/ 9 its t]m9al portion1 & ?icke/ at "s po9t int]m$iate betwe5 ?is & its s\rce1 b ne>] ! latt] ?an ! =m]4 ,cliff & recon/ruct$ glaci]s are comp>able 9 size to ! small] valley glaci]s4 ,pi$mont glaci]s may atta9 great] size4 ,illu/ration3 ,fig4 #bce4--;,a glaci] 9 ! ,cascades ne> ,cascade ,pass1 ,wa%4 ,a glaci] int]m$iate betwe5 a cliff glaci] & a valley glaci]4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,an ice-cap is !oretically ?icke/ at its c5t] & ?9s away to its bord]s1 b its actual dim5sions are influ5c$ by ! topography on :i* x is develop$4 ,! ,gre5l& ice-cap is kn[n to rise ab\t #ijjj feet above ! sea1 & x probably rea*es consid]ably high] ?an ?is 9 ! unexplor$ c5t] ( its broad dome4 ,! height ( ! l& surface b5ea? is unkn[n1 b x is unlikely t x av]ages half ?is am\nt1 & h5ce ! ice is probably #ejjj feet or m ?ick 9 ! c5t]4 ,!re is reason to ?9k t x is mu* ?ick] 9 ,ant>ctica4 ,limits4--,! ice ( a glaci] is always mov+ =w>d 7neglect+ tempor>y halts71 b ! end ( a glaci] may be retreat+1 advanc+ or rema9+ /ation>y1 accord+ z ! rate ( wa/age is great]1 less1 or j equal to ! =w>d movem5t ( ! ice4 ,! position ( ! l[] end ( ! glaci] is !re=e det]m9$ by ! ratio ( movem5t to wa/age4 ,its upp] end is g5]ally ill-def9$4 ,9 a sup]ficial s5se1 x is ! po9t :]e ! ice em]ges f ! sn[-field2 b ! l[] limit ( ! sn[-field is (t5 ill-def9$1 & 9 any case is n ! true upp] limit ( ! glaci]1 s9ce !re mu/ be movem5t f ! granul> mass ( ice b5ea? ! sn[ to make up = ! wa/e bel[1 & ! mov+ ice b5ea? ! sn[-field :i* fe$s ! tongue ( ice 9 ! valley is j z really a "p ( ! glaci] z ! m consolidat$ portion 9 ! valley bel[4 ,if a def9ite upp] limit = an alp9e glaci] is to be nam$1 x %\ld probably be ! ,b]gs*rund1 a gap+ crevasse1 or s]ies ( crevasses :i* sometimes op5 ne> ! precipit\s slope ( ! peak or cliff :]e ! sn[-field lies4 ,! ,b]gs*rund is =m$ by ! mov+ ( ! l[] "p ( ! sn[-field away f ! portion above4 ,! l[] end ( a glaci] is usually free f sn[ & nv 9 summ]1 b1 trac$ t[>d its s\rce1 x fir/ becomes cov]$ ) nv1 !n ) sn[1 & f9ally m]ges into ! sn[-field )\t hav+ ceas$ to be a glaci]4 ,! t]m glaci] is1 h[ev]1 commonly us$ to mean m]ely ! m solid portion outside 7bel[7 ! nv4 ,movem5t4--,! fact ( glaci] movem5t is e/abli%$ 9 v>i\s ways1 ! mo/ obvi\s be+ by ! advance ( its l[] end4 ,su* advance is too sl[ to be se5 f day to day1 & is only detect$ :5 ! l[] end ( ! glaci] ov]rides or ov]turns objects 9 front ( x1 or moves out ov] gr\nd previ\sly unoccupi$4 ,b ev5 :5 ! end ( a glaci] is n advanc+1 ! movem5t ( ! ice may be e/abli%$ by means ( /akes or o!r m>ks set on ! surface4 ,if ! positions ( ^! m>ks relative to fix$ po9ts on ! sides ( ! valley be det]m9$1 !y are f\nd aft] a "t to h mov$ d[n ! valley4 ,r[s ( /akes or l9es ( /ones set across a glaci] 9 ! upp]1 middle & l[] portions h reveal$ _m facts conc]n+ ! movem5t ( ! ice4 ,g5]ally speak+1 ! middle ( a valley glaci] moves m rapidly ?an its sides 7,fig4 #bcf71 b 9 "s cases1 especially 9 l>ge glaci]s1 !re are f\nd to be two or m ma9 l9es ( movem5t1 ) belts ( less] movem5t betwe54 ,! top ( a glaci] moves1 on ! :ole1 m rapidly ?an ! bottom1 ?\gh ! obs]vations made d n %[ t ! rate ( movem5t dim9i%es regul>ly d[nw>d1 & x probably does n s dim9i% 9 _m cases4 ,9 ,switz]l&1 :]e ! glaci]s h be5 /udi$ m c>efully ?an else:]e1 ! det]m9$ rates ( movem5t range f "o or two in*es to f\r feet or m p] day4 ,"s ( ! l>g] glaci]s 9 o!r regions move m rapidly1 b x does n foll[ t l>ge glaci]s always move fa/] ?an small ones4 ,! ,muir glaci] ( ,alaska has be5 f\nd to move sev5 feet or m p] day1#abf & "s ( ! glaci]s ( ,gre5l& h be5 f\nd to move1 9 ! summ] "t1 #ej1 #fj1 or ev5 m feet p] day4 ,a s+le e/imate z high z #ajj feet p] day has be5 made2 b ^! high rates h be5 obs]v$ only :]e ! ice ( a l>ge inl& area cr[ds d[n into a comp>atively n>r[ fjord1 & deb\*es into ! sea1 & !n only 9 ! summ]4 ,9 ! case ( ! glaci] ) ! highe/ record$ rate ( summ] movem5t1 #ajj feet p] day1 ! advance 0 only #cd feet at ab\t ! same place 9 ,april4 ,illu/ration3 ,fig4 #bcf4--;,diagram to %[ ! rate ( movem5t ( ! ,rhone ,glaci] at v>i\s po9ts 9 its c\rse at c5tre & sides4 ,x also %[s ! fluctuations 9 ! positions ( ! end ( ! glaci] betwe5 #ahgd & #ahhb1 & ! pr(ile ( ! ice4 7,heim47 ,! av]age movem5t ( ! bord] ( ! inl& ice ( ,gre5l& is v small4 ,r9k says t 8betwe5 #fb & #fh #cj1 ! edge ( ! inl& ice is almo/ /ation>y = a rem>kably long di/ance40#abg ,! obs]vations ( ! au?ors betwe5 #gg & #gh 7 ( l import4 ,probably ! av]age movem5t ( ! bord] ( ! ,gre5l& ice-cap is less ?an "o foot a week4 ,conditions affect+ rate ( movem5t4--,! rate ( glaci] movem5t appe>s to dep5d on 7#a7 ! dep? ( ! mov+ ice2 7#b7 ! slope ( ! surface ov] :i* x moves2 7#c7 ! slope ( ! upp] surface ( ! ice2 7#d7 ! topography ( ! b$ ov] :i* x passes2 7#e7 ! temp]ature2 & 7#f7 ! am\nt ( wat] :i* falls ^u x or is c>ri$ to x by ! dra9age ( its surr\nd+s1 9 addition to t produc$ by ! melt+ ( ! glaci] itself4 ,great ?ickness1 a /eep slope1 mu* wat]1 smoo?ness ( b$1 & a high 7= ice7 temp]ature favor rapid movem5t4 ,s9ce "s ( ^! conditions1 notably temp]ature & am\nt ( wat]1 v>y ) ! season1 ! rate ( movem5t = any giv5 glaci] is n con/ant ?r\gh\t ! ye>4 ,o!r conditions1 especially ! fir/ ( ^? m5tion$ above1 v>y ?r\gh long] p]iods ( "t1 & occasion p]iodic v>iations 9 ! rate ( movem5t4 ,s9ce ! volume ( ice conc]n$ influ5ces ! rate ( movem5t1 any?+ :i* *anges ! volume affects ! rate4 ,an excess ( sn[fall ) favorable conditions = its pres]vation = a p]iod ( ye>s1 increases ! volume ( ice1 & t5ds to accel]ate its movem5t4 ,a defici5cy 9 sn[fall1 or 9 its pres]vation1 z f high av]age temp]ature or f aridity1 dim9i%es ! quantity ( ice1 & s ret>ds ! movem5t4 ,an accel]ation ( velocity causes ! ice to move d[n ! valley f>!r be=e be+ melt$1 t is1 causes ! end ( ! glaci] to advance1 :ile a decrease ( velocity produces ! opposite effect4 ,z a matt] ( fact1 ! l[] ends ( glaci]s advance = a p]iod ( ye>s & !n retreat1 to advance aga9 at a lat] "t4#abh ,obs]vation has %[n t ! p]iods ( advance foll[ a succession ( ye>s :5 ! sn[fall has be5 heavy & ! temp]ature l[1 :ile ! p]iods ( retreat foll[ a succession ( ye>s :5 ! sn[fall has be5 light & ! temp]ature above ! av]age4 ,! p]iods ( advance & retreat lag beh9d ! p]iods ( heavy & light sn[fall respectively1 by "s ye>s1 & a long glaci] responds less promptly ?an a %ort "o4 ,pres5t k seems to po9t to a p]iod ( #ce to #dj ye>s z ! "t )9 :i* a cycle ( fluctuation1 t is1 an advance & a retreat1 takes place4 ,a decl9+ upp] surface is ess5tial to glaci] motion4 ,!re are %ort /ret*es :]e ?is is n ! case1 & inde$ !re are p>ticul> places :]e ! upp] surface slopes backw>d4#abi ,?is may occur :]e ! ice is pu%$ up ov] a swell 9 its b$1 or is cr[d$ up aga9/ any consid]able ob/acle2 b su* cases are no m ?an local exceptions1 & d n militate aga9/ ! tru? ( ! g5]al /atem5t t ! upp] surface ( a glaci] decl9es 9 ! direction ( motion4 ,a decl9+ l[] surface is less necess>y4 ,9 ! case ( valley glaci]s1 ! b$ does1 z a rule1 decl9e 9 ! direction ( motion1 b t !re are local exceptions is %[n by ! deep bas9s 9 rock :i* su* glaci]s (t5 leave beh9d !m :5 !y retreat4 ,9 ! great cont95tal glaci]s ( rec5t geologic times1 ! ice frequ5tly mov$ up slopes = scores1 & ev5 hundr$s ( miles2 b 9 all su* cases1 ! upp] surface mu/ h decl9$ 9 ! direction ( movem5t4 ,) a giv5 ?ickness ( ice1 ! great] ! decl9e ( its l[] surface 9 ! direction ( motion1 ! m rapid its progress4 ,a r\gh b$1 or a crook$ c\rse ret>ds ! motion ( a glaci]1 :ile a smoo? bottom & a /raight c\rse facilitate x4 ,slope1 r\ghness ( b$1 & volume affect ! movem5t ( glaci]s some:at z !y affect ! movem5t ( riv]s4 ,! temp]ature ( ! wat]1 on ! o!r h&1 has little effect on ! fl[ ( a riv] s long z x rema9s unfroz52 b ! effect ( temp]ature on ! motion ( ice is mo/ important4 ,9 _m cases1 inde$1 ! temp]ature1 toge!r ) ! wat] t is incid5tal to x1 seems to be ! *ief factor 9 det]m9+ ! rate ( movem5t4 ,! way 9 :i* its effects are felt w be discuss$ lat]4 ,lik5esses & unlik5esses ( glaci]s & riv]s4--,_m ( ! *>act]i/ics ( a valley glaci] may be und]/ood f ! /udy ( ! accompany+ figure 7,fig4 #bcg7 ( ! ,:ite 7,alaska7 glaci]4 ,f ?is figure x w be se5 t ! glaci] is an elongate riv]-l body1 foll[+ ! curves ( ! valley 9 /ream-l fa%ion4 ,x has its orig9 9 ! sn[s collect$ on ! m\nta9 heights se5 9 ! di/ance1 & x works its way d[n ! valley 9 a mann] :i*1 9 ! aggregate1 is simil> to ! movem5t ( a /iff liquid4 ,! lik5ess to a riv] ext5ds to _m details4 ,n only does ! c5t] move fa/] ?an ! sides1 & ! upp] "p fa/] ?an ! bottom1 z 9 ! case ( /reams1 b ! movem5t is m rapid 9 con/rict$ portions ( ! valley & sl[] 9 ! broad] p>ts4 ,^! & o!r lik5esses1 "s ( :i* are app>5t r ?an real1 h giv5 orig9 to ! view t glaci] ice moves l a /iff visc\s liquid4 ,illu/ration3 ,fig4 #bcg4--,:ite glaci] 7c5tral backgr\nd7 jo9+ a l>g] glaci] 7=egr\nd71 ,alaska4 7,reid47 ,b :ile ! po9ts ( lik5ess betwe5 glaci]s & riv]s are sev]al1 _! diff]5ces are at lea/ equally num]\s & significant4 ,! tra9s ( dbris on ! surface 7! d>k b&s 9 ! illu/ration71 l ! c5tral curr5ts ( /reams1 pass ne>] ! project+ po9ts ( ! valley walls & f>!r f ! rec$+ b5ds2 b beyond ?is po9t ! analogy fails1 = ! tra9s ( dbris on ! ice d n con=m 9 detail to ! c\rses ( ! curr5ts ( a w9d+ /ream1 nor is !re evid5ce ( ! rotatory motion t *>act]izes riv] wat]4 ,fur!rmore1 ! glaci] is readily fractur$1 z ! num]\s gap+ crevices on _m glaci]s %[4 ,! crevasses are sometimes longitud9al1 sometimes transv]se1 & sometimes oblique4 ,9 ! case ( ,arctic glaci]s1 longitud9al crevass+ is especially conspicu\s4 ,illu/ration3 ,fig4 #bch4--;,crack+ ( glaci] due to *ange 9 grade ( b$4 ,a ,nor? ,gre5l& glaci] ov]rid+ a m\nd ( mora9e-/uff4 ,crevasses appe> to be develop$ :]ev] !re is appreciable t5sion1 & ! causes ( ?is t5sion are _m4 ,an obvi\s cause is an abrupt increase ( gradi5t 9 ! b$ 7,fig4 #bch74 ,if ! *ange ( gradi5t be consid]able1 an ice-fall or cascade results1 & ! ice may be greatly riv5 7,fig4 #bbh74 ,bel[ ! cascade1 ! surface may bri/le ) w$ges & p9nacles ( ice 7sracs1 ,fig4 #bci74 ,transv]se crevices at ! m>g9 sometimes appe> to be ! result ( ! t5sion develop$ on a curve4 ,oblique crevices on ! surface ne> ! sides are commonly ascrib$ to ! t5sion betwe5 ! fa/]-mov+ c5t] & ! sl[]-mov+ m>g9s1 & 9 l mann] crevasses t rise obliquely f ! bottoms are attribut$ to ! t5sion betwe5 ! fa/]-mov+ portions above & ! sl[]-mov+ portions bel[4 ,all ^! crevasses indicate /ra9s to :i* a liquid1 ^: pressures are equal 9 all directions1 does n (f] a close analogy4 ,longitud9al crevasses may affect bo? ! riv]-l "p ( a glaci] & its deploy+ end1 & are ! result ( t5sion develop$ by movem5t )9 ! ice itself1 to :i*1 aga91 riv]s (f] no analogy4 ,some:at simil> cracks develop 9 ! out] cru/ ( asphalt1 :5 a mass ( x is all[$ to /& & spread2 b 9 ?is case !re is evaporation ( ! volatile +r$i5ts1 giv+ to ! out] "p relative rigidity & brittl5ess1 :ile ! inn] "p rema9s m flu5t4 ,! analogy is !re=e n p]fect & probably n really illu/rative4 ,! crevices may be n>r[ or wide1 & bo? n>r[ & wide may be f\nd 9 ! same glaci]4 ,! n>r[ crevices t nev] op5 mu* are ! mo/ significant1 z !y %[ t v little /ret*+ is ne$$ to satisfy ! t5sion4 ,! op5+ ( a gap+ crevice is sometimes ! "w ( weeks1 &1 9 ! sl[-mov+ glaci]s ( high latitudes1 sometimes ! "w ( successive seasons4 ,all ?is %[s t ! glaci] is a v brittle body1 incapable ( resi/+ ev5 v mod]ate /ra9s br\ght to be> ^u x v sl[ly4 ,_h ! ice ev5 mod]ate ductility1 x w\ld adapt itself to t5sion br\ght to be> ^u x s sl[ly z are _m ( ! t5sions :i* produce crevass+4 ,9 its behavior "u t5sion !re=e a glaci] is notably unlike a riv]4 ,illu/ration3 ,fig4 #bci4--,sracs ( glaci]4 7,reid47 ,,surface ,,features4 ,topography4--,_m ( ! m9or irregul>ities ( ! surface ( a glaci] are ! result ( crevass+4 ,aft] ! ice is crevass$1 ! sun's rays & ! air :i* has be5 w>m$ by !m p5etrate ! op5+s & melt ! ice4 ,! melt+ is mo/ rapid at ! top1 & decreases d[nw>d4 ,! result is t ! sections ( ice betwe5 adjac5t crevasses are n>r[$ into w$ges4 ,if !re be cross-crevass+1 z is common1 po9ts in/ead ( w$ges result4 ,z ! sort ( surface %[n 9 ,fig4 #bci develops1 any dbris :i* 0 on ! ice slides into ! crevices1 & ! upp] surface becomes clean4 ,:]e ice is crevass$ transv]sely1 & :]e melt+ is n rapid1 ! crevasses may close z ! ice moves =w>d1 & ! regelation ( adjo9+ faces heals ! r5ts 9 ! surface4 ,ev5 9 ?is case1 h[ev]1 ! surface is likely to be m or less undulat+ because ( ! wa/e on ! sides ( ! crevices be=e !y are clos$4 ,aft] regelation1 surface ablation t5ds to oblit]ate ! protub]ances4 ,! topography ( ! surface ( ! ice is affect$ by o!r conditions4 ,all p>ts ( ! surface ( ! ice are n equally compact1 & ! lea/ compact portions melt mo/ rapidly1 giv+ rise to depressions1 :ile ! m solid p>ts occasion protub]ances4 ,bo? depressions & protub]ances may be regul> or irregul> 9 =m 7,figs4 #bdj & #bda74 ,undulations ( ! b$ (t5 %[ !mselves 9 ! surface ( ! ice z sugge/$ by ,fig4 #bdb4 ,9 su* cases1 ponds or lakelets sometimes accumulate on ! surface ( ! ice4 ,! topography ( ! ice 9 su* cases seems to %[ t ! ice is =c$ up slope4 ,surface mora9es4--,! surface ( a glaci] is (t5 affect$ by dbris ( "o sort or ano!r1 & ?is also influ5ces its topography4 ,! dbris is sometimes dispos$ 9 ! =m ( belts or mora9es 7,figs4 #bcg1 #bdc74 ,! surface mora9es may be lat]al1 m$ial1 or t]m9al4 ,a lat]al mora9e is any consid]able accumulation ( dbris 9 a belt on ! side ( a glaci]4 ,a m$ial mora9e is a simil> accumulation at "s di/ance f ! m>g9s1 b n necess>ily 9 or ne> ! middle4 ,!re may be sev]al m$ial mora9es on "o glaci]1 9 :i* case "s ( !m may be f> f ! c5t]4 ,9 alp9e glaci]s1 ! surface t]m9al mora9e is less well-def9$2 9 pol> glaci]s x (t5 connects two lat]al mora9es1 mak+ a loop r\ghly conc5tric ) ! t]m9us ( ! glaci]4 ,illu/ration3 ,fig4 #bdj4--;,end ( ,m\nt ,dana glaci]1 ,cal4 ,%[s irregul>ities ( surface due to crevass+ f>!r up ! glaci]1 & to unequal melt+4 ,illu/ration3 ,fig4 #bda4--,%[s irregul>ities due to unequal melt+ ( ve9$ ice4 ,end ( small glaci] s\? ( ,=no hut1 ,engad9e1 ,switz]l&4 7,reid47 ,besides ! surface mora9es1 :i* repres5t belt$ aggregations ( dbris1 !re may be scatt]$ b[ld]s & bits ( rock ( v>i\s sizes on ! ice1 &1 9 addition to ! co>se mat]ial1 !re is (t5 "s du/ :i* has be5 bl[n ^u ! ice4 ,relief due to surface dbris4--,! dbris on ! ice affects its topography by influ5c+ ! melt+ ( ! subjac5t & adjac5t ice4 ,! rock dbris absorbs heat m readily ?an ! ice4 ,a small & ?9 piece ( /one ly+ on ! ice is w>m$ ?r\gh by ! sun's rays1 &1 melt+ ! ice b5ea?1 s9ks1 j z a piece ( black clo? on sn[ w s9k because ( ! increas$ melt+ b5ea? x4 ,?\gh a good absorb] ( heat1 rock is a poor conductor1 & s ! l[] surface ( a l>ge mass ( /one is n notably w>m$4 ,! ice b5ea? x is protect$ f ! direct rays ( ! sun1 & is !re=e melt$ m sl[ly ?an t ar\nd x4 ,! result is t ! b[ld] pres5tly /&s on a protub]ance ( ice 7,fig4 #bdd74 ,:5 its p$e/al becomes high1 ! oblique rays ( ! sun & ! w>m air surr\nd+ x cause x to wa/e away1 & ! capp+ b[ld] falls4 ,9 high latitudes1 ! great obliquity ( ! rays sometimes all[s !m to /rike "u isolat$ b[ld]s4 ,9 ?is case1 !y are w>m$ f bel[1 & ?us aid r ?an h9d] ! melt+ ( ! ice4 ,illu/ration3 ,fig4 #bdb4--;,irregul> surface due to unev5 bottom4 ,b[do9 glaci]1 ,+lefield ,gulf1 ,nor? ,gre5l&4 ,! d>k pat*es ne> ! left m>g9 ( ! glaci] are lakelets 9 bas9s produc$ by ! upw>d b5d+ ( ! ice z x ov]rides an elevation 9 its b$4 ,! figure also %[s a depress$ m$ial mora9e4 ,! same pr9ciples apply to ! mora9es4 ,a ?9 b[ld] mora9e 9 high latitudes is sometimes sunk bel[ ! surface 7,fig4 #bdb74 ,usually1 h[ev]1 a m$ial mora9e protects ! ice b5ea? f melt+1 & occasions ! developm5t ( a ridge ( ice b5ea? itself4 ,z ! ice on ei!r side is !n l[]$ by ablation1 ! mora9e matt] ( ! m$ial belt t5ds to slide d[n on ei!r h&4 ,! same is true ( ! lat]al mora9es4 ,s f> does ?is spread+ g1 t 9 "s cases ! l[] end ( a glaci] is completely cov]$ ) ! dbris :i* has spread f ! m$ial & lat]al mora9es4 ,examples ( ?is may be se5 9 almo/ any region ( abundant1 long1 alp9e glaci]s4 ,illu/ration3 ,fig4 #bdc4--;,a ,swiss glaci]1 %[+ surface mora9es1 *>act]i/ic pr(ile1 etc4 ,du/-wells4--,! w9d-bl[n du/ sometimes gives rise to peculi> topographic features ( small size4 ,! du/ is n di/ribut$ by ! w9d ) absolute equality1 & ! surface dra9age ( ! ice t5ds to aggregate x4 ,e du/ p>ticle acts l a small /one1 & :]e aggregations ( du/ occur1 !y melt _! way d[n into ! ice1 develop+ holes or 8du/-wells0 7,fig4 #bde74 ,^! wells r>ely rea* a dep? ( m ?an a few in*es1 b !y may be s num]\s t ! p$e/rian is oblig$ to wat* 8 /eps4 ,?is is especially true ne> ! edge ( ! l>ge ice-caps4 ,x is evid5t t ! dep? ( ^! du/ wells mu/ be slight1 = s soon z !y are deep en\gh to cut (f ! sun's rays f ! du/ at ! bottom1 ! deep5+ ceases4 ,o!r ?+s be+ equal1 !y are deep] 9 l[ latitudes ?an 9 high4 ,illu/ration3 ,fig4 #bdd4--;,b[ld] on ice p9nacle4 ,=no glaci]1 ,switz]l&4 7,reid47 ,illu/ration3 ,fig4 #bde4--;,du/-wells4 ,igloodahomyne glaci]1 ,nor? ,gre5l&4 ,illu/ration3 ,fig4 #bdf4--;,disposition ( dbris 9 ice4 ,nor? ,gre5l& glaci]4 7,libbey47 ,illu/ration3 ,fig4 #bdg4--,pr(ile ( ! l[] "p ( ! lat]al m>g9 ( a glaci]4 ,s\!a/ side ( ,mc,cormick ,bay1 ,nor? ,gre5l&4 ,dbris bel[ ! surface4--,! l[] "p ( a glaci]1 z well z ! upp]1 c>ries rock dbris4 ,?is dbris is sometimes s abundant1 especially ne> ! ends & edges ( ! ice1 t x is difficult to locate ! bottom ( ! glaci]2 = betwe5 ! mov+ ice :i* is full ( dbris1 & ! /ation>y dbris :i* is full ( ice1 !re seems to be a ne>ly complete gradation4 ,! dbris 9 ! l[] "p ( arctic glaci]s1 & to "s ext5t ( o!rs1 is (t5 dispos$ 9 ?9 %eets s&wi*$ 9 betwe5 lay]s ( clean ice4 ,^! dbris %eets are (t5 num]\s & usually discont9u\s1 ?\gh gr\ps ( su* %eets (t5 p]si/ = consid]able di/ances4 ,dbris also occurs to "s ext5t 9 ! ice well above its base4 ,x is sometimes 9 belts1 z se5 9 section1 & sometimes 9 bun*es4 ,^! v>i\s relations are illu/rat$ by ,figs4 #bbg1 #bbi1 & #bdf-bdi4 ,ano!r *>act]i/ic ( ! basal dbris-lad5 "p ( "s glaci]s is ! foliation ( ! ice 7,figs4 #bdh1 #bdi1 etc474 ,?is is especially well %[n 9 ! arctic glaci]s1 ! ends & sides ( :i* h /eep or v]tical faces4 ,! foliation is be/ develop$ 9 ! dbris zone1 ?\gh (t5 %[n above4 ,! foliation is sometimes m9ute1 consi/+ ( lay]s ( clean ice1 an in* or less 9 ?ickness1 sep>at$ by m]e films ( e>?y matt]4 ,9 extreme cases !re are a score or m ( lam9 )9 a foot4 ,locally1 & especially :]e dbris is abundant1 ! lam9 are mu* contort$4 ,?is is se5 bo? 9 section 7,figs4 #bdh & #bdi7 & on ! surface 7,fig4 #bej74 ,,temp]ature1 ,,wa/e1 ,,& ,,dra9age4 ,! temp]ature ( glaci] ice may range d[nw>d f ! freez+ po9t ( wat] mu* z o!r solid portions ( ! e>?'s surface1 b x has a fix$ upp] limit at #cb ,fahr4 7#j ,c47 because all ! heat x receives t5d+ to raise its temp]ature above t po9t1 is conv]t$ into ! lat5t =m by ! melt+ ( ! ice4 ,! range ( temp]ature is greate/ at ! surface1 :]e x v>ies f #cb 9 ! summ]1 to ! colde/ temp]ature ( ! region :]e ! ice occurs4 ,b5ea? ! surface ! range ( temp]ature is m re/rict$1 & increas+ly s ) increas+ dep?4 ,illu/ration3 ,fig4 #bdh4--,side view ( end ( glaci]4 ,s\!a/ side ( ,mc,cormick ,bay1 ,nor? ,gre5l&4 ,%[s /ructure ( ice z well z position ( dbris4 ,! v>iation ( temp]ature at ! surface is due prim>ily to ! v>y+ temp]ature ( ! air4 ,dur+ ! cold season1 a wave ( l[ temp]ature 7! w9t] wave71 />t+ at ! surface1 p5etrates ! ice1 & dur+ ! w>m season a wave ( high] temp]ature 7! summ] wave7 takes ! same c\rse4 ,! day & night waves & o!r m9or v>iables are1 = pres5t purposes1 negligible4 ,illu/ration3 ,fig4 #bdi4--,side view ( a ,nor? ,gre5l& glaci] 7,ea/ glaci]71 %[+ position ( dbris & /ructure ( ! ice4 ,! w9t] wave4--,!re are b few obs]vations on ! int]nal temp]atures ( glaci]s dur+ ! w9t] season1 b x seems c]ta9 t ! w9t] wave dim9i%es rapidly d[nw>d & dies out bel[1 mu* z does ! w9t] wave :i* affects l& surfaces n cov]$ ) ice4 ,conduction alone consid]$1 ! temp]ature ( ! ice :]e ! cold wave dies out1 %\ld correspond1 approximately1 to ! mean annual temp]ature ( ! region1 provid$ t temp]ature is bel[ ! melt+ po9t ( ice4 ,assum+ t 9 ! high altitudes & high latitudes :]e glaci]s ab\nd1 ! temp]ature ( ! surface may av]age ab\t -#ab ,fahr4 7ab\t -#be ,c47 = ! w9t] half ( ! ye>1 :i* is ab\t ! case = nor? ,gre5l&1 ,spitzb]g51 & ,franz ,josef ,l&1 & t ! conductivity ( ! ice 9 ! ,c4 ,g4 ,s4#acj sy/em is 4#jje1 ! temp]ature w\ld be l[]$ appreciably only ab\t #dj feet bel[ ! surface at ! close ( ! w9t] p]iod1 conduction only be+ consid]$4 ,h[ f> ! int]nal temp]ature may be influ5c$ by air =c$ ?r\gh ! ice by w9ds & by v>iations ( ! b>omet] is n kn[n & _c well be e/imat$4 ,! wave ( l[ temp]ature desc5d+ f ! surface 9 w9t] w\ld probably become inappreciable be=e rea*+ a dep? ( #fj feet4 ,at ?is dep? ! temp]ature %\ld be ab\t #ae ,fahr4--! mean annual temp]ature ( ! region4 ,illu/ration3 ,fig4 #bej4--;,contort$ lam9ation %[n at ! surface4 ,a small glaci] s\? ( ,=no hut1 ,engad9e1 ,switz]l&4 7,reid47 ,! summ] wave4--,! w>m wave foll[s ! analogy ( ! summ] wave ( ice-free l& surfaces mu* less closely4 ,?is is because ( ! l[ melt+ temp]ature ( ice z comp>$ ) o!r =ms ( solid e>?-matt]4 ,on ?is acc\nt ! summ] wave is bi-fold4 ,! "o "p travels d[nw>d by conduction1 ! o!r by ! desc5t ( wat]2 ! "o has to d prim>ily ) ! temp]ature be=e ! melt+-po9t ( ice is rea*$2 ! o!r1 ) ! temp]ature aft] t po9t is rea*$2 ! fir/ con=ms measurably to ! w>m wave affect+ o!r solid e>?-matt]1 :ile ! second is gov]n$ by special laws4 ,aft] ! surface portion ( ! ice is br\ght to ! melt+ temp]ature1 ! additional heat :i* x receives melts ! ice & is trans=m$ f s5sible into pot5tial heat4 ,ice *>g$ ) wat] is pot5tially1 b n s5sibly1 w>m] ?an ice :i* has j rea*$ ! melt+ temp]ature4 ,! w>m wave ( conduction dies out bel[ l ! cold wave4 ,! w>m wave desc5d+ by ! fl[ ( wat] /ops :]e ! freez+ temp]ature ( wat] is rea*$4 ,9 regions :]e ! av]age temp]ature is bel[ freez+1 ! wat]-wave does n desc5d s f> z ! wave ( conduction1 s9ce ! latt] desc5ds bel[ ! zone :]e ! melt+ temp]ature is f\nd4 ,! =ego+ consid]ations w>rant ! g5]alization t glaci]s normally consi/ ( two zones 7#a7 an out] or upp] zone ( fluctuat+ temp]ature1 & 7#b7 an "u zone ( ne>ly con/ant temp]ature4 ,! "u zone obvi\sly does n exi/ :]e ! ?ickness ( ! ice is less ?an ! ?ickness ( ! zone ( fluctuat+ temp]ature4 ,?is may be ! case 9 v ?9 glaci]s 9 v cold regions1 & 9 ! ?9 ends & edges ( all glaci]s4 ,! temp]ature ( ! bottom4--,! int]nal heat ( ! e>? is sl[ly conduct$ to ! base ( a glaci] :]e x melts ! ice at ! e/imat$ av]age rate ( ab\t "o-f\r? ( an in* p] ye>4 ,! temp]ature ( melt+ is a little bel[ #cb ,fahr4 s9ce pressure l[]s ! melt+-po9t at ! rate ( 4#jacc ,fahr4 74#jjge ,c47 = "o atmosph]e ( pressure4 ,at ! bottom ( a mile ( ice !re=e ! melt+ temp]ature is ab\t #cj4b ,fahr4 7-#a ,c47 ,x is probable t 9 all ?ick glaci]s ! temp]ature ( ! bottom is con/antly ma9ta9$ at ! melt+-po9t4 ,?is may be indicat$ by ! /reams :i* issue f b5ea? glaci]s dur+ ! w9t]1 ?\gh ?is crit]ion is h>dly decisive s9ce ! issu+ wat]s may be d]iv$ p>tly or :olly f ! rock b5ea?4 ,9 glaci]s or 9 p>ts ( glaci]s s ?9 z to lie :olly )9 ! zone ( fluctuat+ temp]ature1 ! temp]ature ( ! bottom is obvi\sly n con/ant4 ,temp]ature ( ! int]ior ( ! ice4--,! v>iation ( temp]ature ( ! surface ( a glaci] has already be5 %[n to lie betwe5 a maximum ( #cb ,fahr4 & ! m9imum temp]ature ( ! region :]e ! glaci] occurs4 ,l[]1 9 ! zone ( fluctuat+ temp]ature1 ! v>iation is less1 & :]e ! zone ( fluctuat+ temp]ature passes into ! zone ( con/ant temp]ature1 v>iation ceases4 ,! ?ickness ( ! zone ( fluctuat+ temp]ature v>ies ) ! temp]ature ( ! region :]e ! glaci] occurs1 be+ greate/ :]e ! w9t]s are colde/4 ,9 ! case ( all glaci]s except ?9 ones 9 v cold regions1 ! temp]atures )9 ! zone ( con/ant temp]ature range f ! mean annual temp]ature ( ! region at ! top ( ! zone 7provid$ ?is is n above ! melt+-po9t ( ice at ?is dep?7 to ! melt+ temp]ature ( ! ice at ! bottom4 ,)9 ^! limits ! range may be great or slight4 ,if we consid] only ! effects ( ! ext]nal seasonal temp]atures & ! int]nal heat ( ! e>?1 x appe>s t all ! ice 9 ! zone ( con/ant temp]ature 9 ! l[] end ( a typical alp9e glaci] %\ld h a con/ant melt+ temp]ature1 = ! av]age temp]ature ( regions :]e ! ends ( su* glaci]s occur is usually above #cb ,fahr41 & ?is det]m9es a temp]ature ( #cb ,fahr4 7or a little less7 at ! top ( ! zone1 :ile a melt+ temp]ature is ma9ta9$ at ! bottom by ! e>?'s int]ior heat4 ,9 ?9 glaci]s ( v cold regions1 :]e ! zone ( con/ant temp]ature has relatively slight ?ickness1 ! l[ temp]ature desc5d+ f ! surface may s f> ov]come ! effect ( int]nal heat z to keep ! bottom ( ! ice at a freez+ temp]ature4 ,9 all o!r cases1 ! ice at ! bottom ( ! "u zone has a melt+ temp]ature1 :ile t above is probably cold]4 ,9 ! high] altitudes & 9 ! pol> latitudes :]e glaci]s are *iefly g5]at$1 ! mean annual temp]ature ( ! surface is usually bel[ ! melt+-po9t ( ice4 ,"h ! temp]ature ( ! ice betwe5 ! top & bottom ( ! zone ( con/ant temp]ature mu/1 on ! av]age1 be bel[ ! melt+-po9t1 unless heat en\gh is g5]at$ 9 ! int]ior ( ! ice to (fset ! effect ( ! temp]ature above4 ,= example1 :]e ! mean annual temp]ature is #bj ,fahr4 or l[]1 z 9 middle ,gre5l&1 ,spitzb]g51 & ,franz ,josef ,l&1 & at c]ta9 high altitudes 9 m s\!rly latitudes1 ! mean temp]ature 9 ! zone ( con/ant temp]ature %\ld range f #bj ,fahr4 at ! top to #cb ,fahr4 7or a little less7 bel[2 i4e41 x %\ld av]age ab\t #f bel[ ! melt+-po9t4 ,"u ^! conditions1 all ! ice 9 ! zone ( con/ant temp]ature1 except t at its bottom1 mu/ be p]man5tly bel[ ! melt+-po9t1 b x is p]haps wor?y ( especial note t mu* ( x is b little bel[4 ,9 alp9e glaci]s ! "p ( ! ice affect$ by ?is con/ant l[ temp]ature 7bel[ freez+7 is presum$ to be *iefly t :i* lies b5ea? ! sn[-fields4 ,9 pol> glaci]s ! l[ temp]ature probably prevails b5ea? ! surface1 n only ?r\gh\t ! great ice-caps1 b also 9 ! m>g9al glaci]s :i* desc5d f !m4 ,f ^! !oretical consid]ations we may d$uce ! g5]alization t 9 ! zone ( con/ant temp]ature )9 ! area ( glacial gr[?1 ! temp]ature ( ! ice is g5]ally bel[ ! melt+-po9t1 :ile )9 ! area ( wa/age1 ! temp]ature ( ! correspond+ zone is g5]ally at ! melt+-po9t4 ,compression & friction z causes ( heat4--,! =ego+ conclusions are some:at modifi$ by dynamic s\rces ( heat4 ,! compression aris+ f gravity1 & ! friction develop$ :]e !re is motion1 are causes ( heat4 ,s9ce friction occurs only :5 motion takes place1 ! heat :i* x g5]ates is second>y & may1 = pres5t purposes1 be neglect$4 ,compression n only l[]s ! melt+-po9t slightly1 b x produces heat at ! po9t ( compression4 ,:]e ! ice is granul>1 ! compression1 due to weight1 takes place at ! contacts ( ! gra9s4 ,at int]m$iate po9ts ! pressure t5ds to cause !m to bulge1 & ?is has ! effect ( l[]+ ! temp]ature ( ! bulg+ po9ts4 ,if !re=e ! compression be consid]able1 ! granules may be w>m$ to ! melt+-po9t :]e !y press ea* o!r1 :ile at o!r po9ts _! temp]ature may be l[]4 ,9 ?is case melt+ w take place at ! po9ts ( compression1 & ! moi/ure s produc$ w be transf]r$ to ! adjac5t p>ts ( ! granule & imm$iately refroz54 ,melt+ at ! po9ts ( compression w\ld result 9 "s yield+ ( ! mass1 & 9 "s %ift+ ( ! pressure to new po9ts :]e compression & melt+ w\ld aga9 take place4 ,?us ! melt+1 ! refreez+1 & ! att5dant movem5t might g on until ! limits ( ! p[] ( gravity 9 ?is direction 7 rea*$4 ,f consid]ations already adduc$1 x appe>s t ! temp]ature 9 "s p>ts ( e consid]able body ( ice mu/ be su* z to p]mit ^! *anges4 ,! heat due to depression & friction may modify ! !oretical d$uctions drawn above f atmosph]ic & int]nal influ5ces4 ,summ>y4--,if ! =ego+ g5]alizations be correct1 7#a7 ! surface ( a glaci] is likely to be melt$ dur+ ! summ]1 7#b7 its imm$iate bottom is sl[ly melt+ all ! "t 7unless ! ?ickness ( ! ice be less ?an ! ?ickness ( ! zone ( annual v>iation or ( p]man5t freez+ temp]ature72 7#c7 its subsurface portion 9 ! zone ( wa/e is g5]ally melt+1 ow+ to desc5d+ wat]1 compression1 & friction2 :ile 7#d7 its subsurface portion 9 ! zone ( gr[? is probably bel[ ! melt+-po9t except z locally br\ght to t temp]ature by compression1 friction1 & desc5d+ wat]1 & at ! bottom by conduction f ! rock b5ea?4 ,movem5t "u l[ temp]ature4--,glaci] motion w n be discuss$ at ?is po9t1 b "o ( ! be>+s ( ! prec$+ conclusions on glaci] motion may be po9t$ out4 ,s9ce !re mu/ be motion 9 ! area ( gr[? to supply ! loss 9 ! area ( wa/e1 ! fundam5tal cause ( motion mu/ be op]ative 9 bodies ( ice ! mean temp]ature ( :i* is bel[ ! melt+-po9t1 unless ! dynamic s\rces ( heat are consid]able4 ,?is fundam5tal cause does n exclude ! cop]ation ( causes t "w only 7#a7 at ! melt+ temp]ature1 or 7#b7 :]e ! ice is ba!d ) wat]1 or 7#c7 9 ! plane ( contact betwe5 wet ice above & dry ice bel[4 ,^! may be auxili>y causes :i* abet ! fundam5tal "o 9 produc+ ! m rapid movem5t ( w>m seasons1 or 9 br++ ab\t ! especially rapid movem5t 9 situations :]e !re is abundant wat]1 or 9 induc+ ! %e>+ :i* is su* a rem>kable feature ( arctic glaci]s4 ,evaporation4--,! ice wa/es by evaporation z well z by melt+1 & :ile ! =m] process is f> less important ?an ! latt]1 its results are probably l>g] ?an is commonly appreh5d$4 ,"o ( ! mo/ rem>kable features ( "s ( ! deposits ( anci5t glaci]s is ! slight evid5ce !y af=d ( escap+ wat]s4 ,! mo/ plausible explanation seems to lie 9 ! supposition t ! ice 0 l>gely wa/$ by evaporation4 ,?is conclusion f9ds support 9 _m places 9 ! pres5ce ( a mantle ( f9e silt ov] ! drift1 ! silt be+ app>5tly compos$ ( du/ bl[n ^u ! ice4 ,x is suppos$ to imply aridity 9 ! region ab\t ! ice4 ,if a suffici5t mantle ( du/ 7 spread ov] ! bord] zone ( ! ice1 & if ! air 7 v dry1 ne>ly all ! wat] melt$ on ! surface ( ! ice might be held back by ! du/-wells until ! wat] 0 evaporat$ or absorb$4 ,illu/ration3 ,fig4 #bea4--,sp\t+ /ream4 ,glaci] s\? side ( ,olriks ,bay1 ,nor? ,gre5l&4 ,dra9age4--,"s ( ! wat] produc$ by surface melt+ =ms little /reams on ! ice4 ,soon] or lat] !y plunge into crevasses or ov] ! sides & ends ( ! glaci]4 ,9 ! =m] case1 !y may melt or we> out well-l passages 7m\l9s7 9 ! ice1 & ev5 9 ! rock b5ea?4 ,mu* ( ! surface wat] s9ks into ! ice4 ,its ready p5etration is aid$ by ! 8du/-wells0 :i* m>k ! surface ( _m glaci]s4 ,9 nor? ,gre5l& wells :i* conta9 six or eight in*es ( wat] at ! end ( a w>m day are (t5 dry 9 ! morn+4 ,! wat] has leak$ out & pass$ to l[] levels4 ,f ^! & o!r h>moni\s obs]vations x is inf]r$ t ! sup]ficial "p ( a glaci] at lea/ is readily p5etrat$ by wat]4 ,! dep? to :i* surface wat] p5etrates is undet]m9$1 b x d\btless v>ies greatly1 n only 9 diff]5t glaci]s1 b 9 diff]5t p>ts ( ! same glaci]1 & 9 ! same "p at diff]5t times4 ,above ! l9e ( p]5nial sn[ !re is little wat] ei!r f melt+ or f ra91 & h5ce relatively slight p5etration4 ,bel[ ! l9e ( p]5nial sn[ !re is mu* melt+ & mu* ra91 & "h x is probable t ! wat] sometimes1 p]haps usually1 p5etrates to ! bottom ( ! ice dur+ ! melt+ season1 ev5 indep5d5tly ( crevasses4 ,once )9 ! glaci]1 ! c\rse ( ! wat] is v>iable4 ,exceptionally x foll[s def9ite englacial *annels1 z %[n by spr+s or /reams issu+ f ! ice at "s po9t above its bottom 7,fig4 #bea74 ,(t5] x desc5ds or moves =w>d ?r\gh ! irregul> op5+s :i* ! accid5ts ( motion h develop$4 ,if x rea*es a level :]e ! temp]ature is bel[ its freez+-po9t1 x congeals4 ,o!rwise x rema9s 9 cavities or desc5ds to ! bottom4 ,! wat] produc$ by melt+ )9 ! glaci] probably foll[s a simil> c\rse4 ,s f> z ^! wat]s desc5d to ! bottom1 !y jo9 ^? produc$ by basal melt+ & issue f ! glaci] ) !m4 ,9 alp9e glaci]s ! wat]s b5ea? ! ice (t5 unite 9 a common /ream 9 ! axis ( ! valley1 & holl[ out a tunnel4 ,?us ! ,rhone is already a consid]able /ream :]e x issues f b5ea? ! ,rhone glaci]4 ,9 ! glaci]s ( high latitudes1 subglacial tunnels are less common & ! dra9age is 9 /reams along ! sides ( ! glaci]s or ?r\gh ! dbris b5ea? & ab\t !m4 ,at ! end ( ! glaci]1 all wat]s1 :e!r !y h be5 sup]glacial1 englacial or subglacial1 unite to be> away ! silt1 s&1 gravel1 & ev5 small b[ld]s set free f ! ice1 & to spread !m 9 belts along ! bord] ( ! ice or 9 tra9s /ret*+ d[n ! valleys bel[4 ,^! are ! mo/ common ( ! glacio-fluvial deposits4 ,,! ,,"w ,,( ,,glaci]s4 ,erosion & transportation4 ,! "w accompli%$ by glaci]s is di/9ctive1 = :ile l riv]s1 !y abrade ! valleys ?r\gh :i* !y pass1 c>ry =w>d ! mat]ial :i* !y remove f ! surface1 & we>1 gr9d1 & ultimately deposit x1 & :ile _! "w !re=e includes erosion1 transportation1 & deposition1 _! me?od is peculi>4 ,gett+ load4--,if ! surface on :i* ! sn[-field :i* is to become a glaci] accumulates be r\gh & cov]$ ) abundant rock dbris1 z su* surfaces usually are1 ! glaci] already has a basal load :5 its movem5t beg9s1 = ! sn[ cov]s1 surr\nds1 & includes su* loose blocks ( rock z project above ! g5]al surface & envelops all project+ po9ts ( rock )9 its field4 ,:5 ! sn[ becomes ice & ! ice beg9s to move1 x c>ries =w>d ! loose rock already imb$d$ 9 x1 & te>s (f ! weak po9ts ( ! envelop$ rock-projections4 ,x may p]haps also move "s ( ! soil & mantle rock ( ! orig9al surface to :i* x is froz54 ,9 addition to ! subglacial load :i* ! glaci] ?us has at ! outset1 !re may be a surface load :i* has fall5 on ! sn[ or ice f cliffs above4 ,?is is especially true ( m\nta9-valley glaci]s4 ,if ?is has be5 buri$ by sn[ & ice x is englacial2 if x lies on ! surface x is sup]glacial4 ,once 9 movem5t1 ! ice c>ries away ! dbris to :i* x 0 orig9ally atta*$1 & at ! same "t ga!rs new load f ! same area4 ,! new load is acquir$ p>tly by ! rasp+ effect ( ! rock-%od ice on its b$1 & p>tly by its r5d+ p[] :i*1 "u favorable circum/ances1 may qu>ry out consid]able blocks ( rock4 ,?is 8pluck+0 process is at its be/ :]e ! ice passes ov] cliffs ( jo9t$ rock or /eep-slop$ hills4 ,z ! ice advances into new t]ritory x acquires additional basal load1 p>tly by rasp+1 p>tly by pluck+1 p>tly by freez+ to x1 & p>tly 9 o!r ways4 ,"o ( ^! ways may be illu/rat$ by ! sequ5ce ( ev5ts :5 ! end ( a glaci] advances on a v l>ge b[ld]4 ,z ! ice approa*es x1 ! reflection ( heat f x melts ! adjac5t edge ( ! ice1 mak+ a slight rentrant4 ,) f>!r advance1 ! ice closes 9 aga9/ & ar\nd ! b[ld]1 & f9ally c>ries x along 9 ! bottom ( ! mov+ mass4 ,9 "s cases1 especially :5 its advance is rapid1 ! ice may pu% dbris 9 front ( itself4 ,ev5 :]e ?is is ! case1 ! am\nt ( mat]ial pu%$ =w>d is g5]ally slight1 p>tly because ! extreme edge ( ! ice (t5 fails to re/ on ! l& 9 summ]1 :5 ! movem5t is greate/1 be+ melt$ f bel[ by ! heat ( ! surface ov] :i* x is spread+ 7see ,fig4 #beb71 & p>tly because ! e>? 9 front ( ! glaci] is froz5 dur+ a l>ge "p ( ! ye>4 ,9 ?is condition1 ! e>?y matt] has great] resi/ance ?an ! ice1 & ! latt] rides ov] x4 ,sup]glacial mat]ial may be acquir$ dur+ movem5t by ! fall ( dbris f cliffs1 or by ! desc5t ( avalan*es4 ,illu/ration3 ,fig4 #beb4--;,diagram %[+ lack ( contact ( ! edge ( ! ice ) its b$4 ,conditions influ5c+ rate ( erosion4--,an ob/ructive attitude ( ! surface t[>d ! movem5t ( ! ice is z necess>y = effective erosion z ! movem5t ( ! ice itself4 ,advanc+ ov] a flat surface1 ice ord9>ily inflicts b little we>1 s9ce !re is little = x to get hold (4 ,s slight is ! abrasive p[] ( ice "u ^! conditions t x frequ5tly ov]rides & buries ! soil ) m or less ( its h]bace\s vegetation4 ,b :ile a c]ta9 measure ( r\ghness ( surface is favorable = glacial erosion1 ! topography may be s unev5 z to s]i\sly imp$e ! ice4 ,erosion is probably at its maximum1 s f> z influ5c$ by topography1 :5 ! r\ghness ( ! surface is su* z to (f] notable cat*m5t = ! basal ice1 b n su* z to imp$e its motion v s]i\sly4 ,! am\nt ( relief favorable = ! greate/ erosion increases ) increas+ ?ickness ( ! ice4 ,o!r conditions :i* influ5ce erosion by ice are 7#a7 ! am\nt ( loose or slightly atta*$ dbris on ! surface1 7#b7 ! resi/ance ( ! rock1 7#c7 ! slope ( ! surface1 7#d7 ! ?ickness ( ! ice1 7#e7 ! rate ( movem5t1 & 7#f7 ! abundance & "* ( ! dbris :i* ! ice has to "w )4 ,! effect ( ! fir/ five ( ^! conditions is evid5t4 ,! effect ( ! la/ is less simple4 ,clean ice pass+ ov] a smoo? surface ( solid rock has little effect ^u x2 b a rock-%od glaci] w abrade ! same surface notably4 ,! effect ( ?is abrasion is %[n 9 ! grooves & scrat*es 7/ri7 :i* ! /ones 9 ! bottom ( ! ice inflict on ! surface ( ! rock ov] :i* !y pass 7,figs4 #bec1 #bee1 & #bef74 ,at ! same "t ! /ones 9 ! ice are !mselves worn bo? by abrasion ) ! bottom1 & ) "o ano!r 7,fig4 #bed74 ,x does n foll[1 h[ev]1 t ! m mat]ial 9 ! bottom ( ! ice ! great] ! erosion x effects2 = ) increase ( dbris !re may be decrease ( motion#aca &1 beyond a c]ta9 po9t1 ! decrease ( motion s]i\sly int]f]es ) ! effici5cy ( erosion4 ,:5 any consid]able ?ickness ( ice at ! bottom ( ! glaci] is full ( dbris1 ?is load$ basal portion may approa* /agnancy1 & ! l[] limit ( consid]able movem5t may lie betwe5 ! load$ ice bel[ & ! relatively clean ice above4 ,a mod]ate1 b n an excessive load ( dbris is1 !re=e1 favorable = great erosion4 ,some?+ dep5ds1 too1 on ! "* ( ! load4 ,co>se1 h>d1 & angul> dbris is a m effective in/rum5t ( erosion ?an f9e1 s(t1 or r\nd$ mat]ial4 ,! adv]se influ5ce ( ! ov]load+ ( ! ice on its motion has be5 lik5$ to ! /iff5+ ( a visc\s liquid by ! addition ( =eign matt]1 b x may bett] p]haps be ref]r$ to ! de/ruction ( ! granul>-cry/all9e cont9uity on :i* glaci] motion probably dep5ds4 ,illu/ration3 ,fig4 #bec4--;,glacial /ri & bruises4 ,! block to ! "r %[s two sets ( /ri3 t to ! left %[s ! peculi> curv$ fractures kn[n z ,*att] ,m>ks4 ,illu/ration3 ,fig4 #bed4--;,b[ld]s %[+ glacial /riation4 7,drawn by ,miss ,matz47 ,illu/ration3 ,fig4 #bee4--,/ri on b$ rock1 ,k+/on1 ,des ,mo9es ,co41 ,ia4 7,i[a ,geol4 ,surv47 ,f ! prec$+ /atem5t1 x is evid5t t erosion is n equally effective at all po9ts b5ea? a glaci]4 ,s f> z conc]ns ! ice itself1 erosion is n mo/ effective at ! end ( a valley glaci]1 or at ! edge ( an ice %eet1 = "h ! /r5g? ( movem5t is too slight & ! load too great2 nor is ! mo/ effective erosion at ! s\rce or ne> x1 = ?\gh ! ice may "h be ?ick1 ! movem5t is sl[ & ! load likely to be slight4 ,ice conditions only be+ consid]$1 erosion is mo/ effective some:]e betwe5 ! s\rce & ! t]m9us1 & probably mu* ne>] ! latt] ?an ! =m]4 ,! conditions ( ! surface ov] :i* ! ice passes may be su* z to v>y ! place ( greate/ erosion widely4 ,?us 9 an ,alp9e glaci]1 erosion may be mo/ effective at ! ,b]gs*rund because ! slope "h favors 8pluck+40 ,"h1 notable amphi!atres 7cirques7 are sometimes excavat$4 ,aft] ! glaci] disappe>s1 ! bottom ( ! cirque is (t5 se5 to conta9 rock bas9s 7,fig4 #beg74 ,glacial cirques ab\nd 9 m\nta9s :]e glaci]s once exi/$1 b f :i* !y h n[ disappe>$4 ,! cirques ( ! ,bighorn m\nta9s ( ,wyom+ 7,pl4 ,,xix7 are examples4 ,illu/ration3 ,fig4 #bef4--,/ri1 grooves1 etc41 9 a canyon tribut>y to ,big ,cottonwood ,canyon1 ,wasat* ,m\nta9s4 7,*ur*47 ,summ>y4--,9 summ>y x may be said t rapidly mov+ ice ( suffici5t ?ickness to be work+ "u goodly pressure1 %od ) a suffici5t b n excessive quantity ( h>d-rock mat]ial1 pass+ ov] incoh]5t or s(t =mations possess+ a topography ( suffici5t relief to (f] "s resi/ance1 & yet too little to ret>d s]i\sly ! progress ( ! ice1 w erode mo/ effectively4 ,v>i$ nature ( glacial dbris4--,f its mode ( erosion x w readily be se5 t ! bottom ( a glaci] may be *>g$ ) v>i\s sorts ( mat]ial4 ,!re may be 7#a7 b[ld]s :i* ! ice has pick$ up f ! surface1 or :i* x has brok5 (f f project+ po9ts ( rock ov] :i* x has pass$2 7#b7 small] pieces ( rock ( ! size ( cobbles1 pebbles1 etc41 ei!r pick$ up by ! ice f its b$ or brok5 (f f l>g] masses2 7#c7 ! f9e products 7rock-fl\r7 produc$ by ! gr9d+ ( ! dbris 9 ! ice on ! rock-b$ ov] :i* x passes1 & simil> products result+ f ! rubb+ ( /ones 9 ! ice aga9/ "o ano!r2 & 7#d7 s&1 clay1 soil1 vegetation1 etc41 d]iv$ f ! surface ov]ridd54 ,?us ! mat]ials :i* ! ice c>ries 7drift7 are ( all grades ( co>s5ess & f95ess1 f l>ge b[ld]s to f9e clay4 ,! co>s] mat]ial may be angul> or r\nd at ! outset1 & its =m may be *ang$ & its surface /riat$ z x is mov$ =w>d4 ,:e!r "o sort ( mat]ial or ano!r pr$om9ates1 dep5ds prim>ily on ! nature ( ! surface ov]ridd54 ,illu/ration3 ,,plate ,,xix4 ,,"p ,,( ,,! ,,bighorn ,,m\nta9 ,,range1 ,,wyom+4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xx4 ,a ,,section ,,( ,,! ,,cali=nia ,,coa/ ,,ne> ,,san ,,mateo1 ,,cali=nia4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #beg4--;,a glacial cirque4 ,! lake occupies a rock bas91 produc$ by glaci] erosion4 ,head ( ,little ,timb] ,creek1 ,montana4 ,! topographic effects ( glacial erosion4--,9 pass+ ?r\gh its valley1 an alp9e glaci] deep5s & wid5s its bottom & smoo?s its slopes up to ! upp] limit ( ! ice4 ,x t5ds to *ange a ,v-%ap$ valley 7,fig4 #beh7 into a ,u-%ap$ "o 7,fig4 #bei74 ,! *ange 9 topography at ! upp] limit ( glaciation is (t5 m>k$ 7,figs4 #bfj & #bfa74 ,illu/ration3 ,fig4 #beh4--,! ,valley ( ! ,am]ican ,=k4 ,a ,v-%ap$ non-glaciat$ valley 9 ! ,wasat* ,m\nta9s ( ,utah4 ,comp>e ,fig4 #bei4 7,*ur*47 ,illu/ration3 ,fig4 #bei4--,u-%ap$ valley result+ f glaciation4 ,little ,cottonwood ,canyon1 ,wasat* ,m\nta9s4 7,*ur*47 ,illu/ration3 ,fig4 #bfj4--;,contra/ betwe5 glaciat$ topography bel[ & non-glaciat$ topography above4 ,! m9>ets 9 ! ,si]ras1 ,cal4 ,illu/ration3 ,fig4 #bfa4--;,contra/ betwe5 glaciat$ topography bel[1 & non-glaciat$ topography above4 ,ne$les ,m\nta9s1 f slope we/ ( ,hidd5 ,lake4 7,cross1 ,u4 ,s4 ,geol4 ,surv47 ,! deep5+ ( a valley by glacial erosion may ?r[ its tribut>ies out ( topographic adju/m5t4 ,?us if a ma9 valley is l[]$ #ajj feet by glacial erosion :ile its tribut>y is n deep5$1 ! l[] end ( ! latt] w be #ajj feet above ! =m] :5 ! ice disappe>s4 ,su* a valley is call$ a hang+ valley 7,figs4 #bfb & #bfc74 ,su* valleys are ( common occurr5ce 9 regions rec5tly glaciat$1 b n[ ice-free4 ,examples are common 9 ! we/]n m\nta9s ( ,nor? ,am]ica & else:]e4 ,ice-caps :i* ov]spread ! surface irrespective ( valleys & hills1 t5d to r$uce ! angul>ities ( ! surface4 ,hills & ridges are cut d[n & smoo!d 7,figs4 #bfd & #bfe72 b s9ce valleys p>allel to ! direction ( movem5t are deep5$ at ! same "t1 x is d\btful if ! relief ( ! surface is commonly r$uc$ by ! erosion ( an ice-cap4 ,illu/ration3 ,fig4 #bfb4--;,a hang+ valley4 ,ea/ side ( ,lake ,koot5ai1 ,b4 ,c4 ,all except ! highe/ summits glaciat$4 7,atwood47 ,fiords4--,a glaci] desc5d+ into ! head ( a n>r[ bay may g\ge out ! bay to a v consid]able dep?1 caus+ its head to rec$e4 ,:5 ! ice f9ally melts1 ! bay may be a fiord4 ,?us h aris5 ! glacial features ( _m ( ! fiords ( high-latitude coa/s1 & _m ( ! glaci]s ( ^? coa/s are n[ mak+ fiords 7,fig4 #bff74 ,fiords also arise 9 o!r ways4 ,coa/s ind5t$ by fiords are likely to be bord]$ by isl&s4 ,! positions 9 :i* dbris is c>ri$4--,z a result ( ! me?ods by :i* a glaci] becomes load$1 !re are ?ree positions 9 :i* ! dbris is c>ri$3 7#a7 ! basal or subglacial1 7#b7 ! englacial1 & 7#c7 ! sup]glacial4 ,! mat]ial pick$ up or rubb$ (f f ! surface ov] :i* ! ice moves is normally c>ri$ =w>d 9 ! base ( ! ice2 :ile t :i* falls on ! surface is usually c>ri$ 9 ! =m ( surface mora9es4 ,9 ! =m] position ! drift is basal2 9 ! latt]1 sup]glacial4 ,x is d\btful if mu* dbris is mov$ along b5ea? 7t is1 /rictly bel[ ! bottom (7 ! ice1 ?\gh ! movem5t ( ! latt] w\ld h a t5d5cy to drag or urge along ) x ! loose mat]ial ( its b$4 ,if drift 7 c>ri$ =w>d 9 su* positions1 x w\ld be /rictly subglacial4 ,illu/ration3 ,fig4 #bfc4--;,a hang+ valley4 ,! wat] falls 7,bridal ,veil7 f a hang+ valley4 7,w9eman47 ,! basal load ( a glaci] is con/antly be+ mix$ ) new accessions d]iv$ f gr\nd ov] :i* ! ice is pass+1 & ?is admixture tells ! /ory ( ! "w done by ! bottom ( ! ice4 ,! englacial & sup]glacial mat]ial1 on ! o!r h&1 is normally borne f ! place ( orig9 to ! place ( deposition )\t su* int]mixture4 ,x is a case ( 8local0 v]sus 8?r\gh0 transportation4 ,transf]s ( load4--,:ile ! orig9 ( ! load usually det]m9es its position1 exceptions & complications arise f ! transf] ( load f "o position to ano!r1 & f ! gradation ( "o horizon into ano!r4 ,illu/ration3 ,fig4 #bfd4--;,a non-glaciat$ hill4 ,dalrymple ,isl&4 ,nor? ,gre5l&4 ,illu/ration3 ,fig4 #bfe4--;,a glaciat$ hill4 ,s\!a/]n ,c>ey ,isl&4 ,ab\t #cj miles we/-nor?we/ ( ,dalrymple ,isl&4 ,mo/ ( ! dbris ga!r$ by ice is acquir$ at its bottom4 ,:ile su* mat]ial is basal at ! outset1 "s ( x may f9d itself above ! bottom a little lat]4 ,?us :5 ice passes ov] a hill 7,fig4 #bfg7 ! bottom ( ! ice r5ds dbris f ! top ( ! hill4 ,:5 x desc5ds f "o level to ano!r !re is a simil> result 7,fig4 #bfh74 ,to ! lee ( ! hill ! ice f ei!r side may close 9 "u t :i* came ov] ! top1 9 :i* case ! dbris d]iv$ f ! top ( ! hill by ! bottom ( ! ov]rid+ ice w be well up 9 ! ice4 ,x has pass$ f an initial basal to a subsequ5t englacial position4 ,! *ange does n usually involve an actual rise ( ! mat]ial1 b r a decl9e4 ,if c>ri$ upw>d at all1 ! upw>d movem5t is tempor>y only1 & incid5t to ! passage ( ! ice ov] ! hill1 or to o!r local causes4 ,! englacial dbris may be little or mu* above ! basal zone accord+ to ! height ( ! elevation ov]ridd54 ,illu/ration3 ,fig4 #bff4--;,alaskan fiords4 ,! %ad$ areas repres5t l&4 7,f *>ts ( ! ,c4 ,g4 ,surv47 ,illu/ration3 ,fig4 #bfg4--;,diagram to illu/rate ! tak+ ( dbris f a hill-top4 ,x also illu/rates h[ englacial dbris may become sup]glacial z ! result ( surface ablation4 ,illu/ration3 ,fig4 #bfh4--,tak+ dbris f a protub]ance ( ! b$4 ,sup]glacial dbris may obvi\sly become englacial by fall+ into crevasses or by be+ c>ri$ d[n by desc5d+ wat]s4 ,ei!r sup]glacial or englacial dbris may become basal by ! same means4 ,f _! =m & position1 !re is less ice-free l& 9 imm$iate association ) ice-caps ?an ) valley glaci]s4 ,fur!rmore1 ! ice-free l& ab\t ! bord]s ( an ice-cap is less likely to be 9 ! =m ( cliffs above x4 ,z a result1 ! surfaces ( ice-caps are comp>atively clean1 except at _! edges :]e ! ice is ?94 ,illu/ration3 ,fig4 #bfi4--,side view ( end ( a glaci] on ! s\? side ( ,olriks ,bay1 ,nor? ,gre5l&4 ,illu/ration3 ,fig4 #bgj4--;,clos] view ( a "p ( ! ice %[n 9 ,fig4 #bfi4 ,englacial mat]ial may become sup]glacial by surface ablation4 ,9 ?is case ! drift does n rise1 b melt+ br+s ! surface ( ! ice d[n to its level4 ,?is occurs *iefly at ! end or edge ( ! ice1 :]e ! surface melt+ is greate/4 ,englacial dbris1 especially t ne> ! bottom1 may also become basal by ! melt+ ( ! bottom ( ! ice4 ,englacial mat]ial pluck$ or rasp$ f an elevation ov] :i* ! ice has pass$ is liable to be dispos$ 9 a longitud9al belt 9 ! ice 9 ! lee ( ! elevation itself4 ,by surface ablation ?is mat]ial may rea* ! surface at "s po9t bel[ its s\rce1 & be dispos$ z a m$ial mora9e4 ,su* a mora9e has an orig9 v diff]5t f t ( a m$ial mora9e =m$ by ! junction ( two lat]al mora9es ( sup]glacial orig94 ,mu* less 9 ! natural ord] ( ?+s is ! transf] ( mat]ial f a basal to an englacial & f an englacial to a sup]glacial position by upw>d movem5t ( ! dbris itself4 ,su* transf] is rem>kable because ! specific gravity ( rock is f two & a half to ?ree times z great z t ( ice1 s t its normal t5d5cy is to s9k4 ,illu/ration3 ,fig4 #bga4--,surface t]m9al mora9es due to upturn+4 ,edge ( ! ice-%eet1 ,nor? ,gre5l&4 ,9 arctic glaci]s1 & probably 9 o!rs1 "s mat]ial :i* has be5 basal becomes englacial by be+ %e>$ =w>d ov] ice 9 front ( x4 ,s f> z obs]v$ ?is takes place *iefly :]e ! ice 9 front ( ! plane ( %e>+ lies at a l[] level ?an t beh9d1 z :]e ! surface ( an upl& falls (f into a valley1 or :]e a boss ( rock %elt]s ! ice 9 its lee f ! ?ru/ ( ! ov]rid+ ice 7,fig4 #bfh74 ,illu/ration3 ,fig4 #bgb4--;,diagram illu/rat+ ! upturn+ ( ! lay]s ( ice at ! end ( an arctic glaci] z se5 9 end-section4 ,! bottom l9e repres5ts sea level4 ,at ! bord]s ( arctic glaci]s ! l[] lay]s are n infrequ5tly upturn$1 z %[n 9 ,figs4 #bfi to #bgb4 ,:]e ! lay]s turn up at ! end ( a glaci] 7,figs4 #bfi & #bgj71 basal & englacial dbris is c>ri$ to ! surface by actual upw>d movem5t1 & a t]m9al mora9e or a s]ies ( t]m9al mora9es sometimes aggregat$ :]e ! upturn$ lay]s ( ice outcrop at ! surface 7,fig4 #bga74 ,t ! mat]ial ( ^! mora9es 0 orig9ally basal is abundantly demon/rat$ by ! bruis$ & scrat*$ condition ( ! b[ld]s & pebbles1 & sometimes by ! nature ( ! mat]ial itself4 ,= example1 9 two cases 9 ,nor? ,gre5l& :]e glaci]s desc5d into ! heads ( %all[ bays & move =w>d on _! bottoms1 mora9es =m$ by ! upturn+ ( ! lay]s 7 se5 to conta9 abundant molluscan %ells d]iv$ f ! bottom ( ! bay4 ,! upturn+ sometimes affects ! side-edges ( ice-tongues 7,fig4 #bgb7 z well z _! ends1 & ! mat]ial ?us br\ght to ! surface gives orig9 to lat]al mora9es altoge!r diff]5t 9 orig9 f ! lat]al mora9es =m$ by ! fall+ ( dbris ^u ! glaci]s4 ,sometimes also !re is an upturn+ ( ! ice along a longitud9al zone well back f ! lat]al m>g9s 7,fig4 #bgc71 & ! mat]ial s borne to ! surface 9 su* a zone gives rise to a mora9e resembl+ ! m$ial mora9e =m$ by ! union ( lat]al mora9es1 b ( :olly diff]5t orig94 ,illu/ration3 ,fig4 #bgc4--;,diagram illu/rat+ ! same po9t z #bgb1 :]e ! /ructure is m complex4 ,! bottom l9e ( ! figure repres5ts sea level4 ,! ph5om5on ( upturn+ "h ref]r$ to has be5 obs]v$ only at or ne> ! t]m9us ( ! ice1 & is p]haps due 9 mo/ "p to ! resi/ance ( froz5 mora9ic or o!r mat]ial b5ea? & 9 front ( ! edge4 ,to ?is %\ld probably be add$ ! effect ( ! increas$ rigidity ( ! ice at its bord]s1 due to ! l[ ext]nal temp]ature dur+ ! l>g] "p ( ! ye>1 :ile ! int]ior1 ) its high] temp]ature1 rema9s m flu5t4 ,b ev5 ?is probably leaves ! explanation inadequate4 ,9 n a few in/ances ! upturn+ is associat$ ) a notable ?ick5+ ( ! lay]s t[>d _! edges 7,fig4 #bgd74 ,?is sugge/s t p]haps !re is an exceptional gr[? ( ! granul> cry/als ( ! ice ne> ! edge ( ! lay]s1 ow+ to ! p5etration ( ! surface-wat]s :i* are mu* m abundant at ! bord]s ?an else:]e1 & :i* 9 ! arctic glaci]s probably d n p5etrate deeply be=e !y rea* a freez+ temp]ature4 ,we> ( drift 9 transit4--,drift c>ri$ at ! bottom ( ! ice is subject to notable we>4 ,! mat]ials 9 transportation abrade "o ano!r & are abrad$ by ! b$ ov] :i* !y pass4 ,englacial drift is subject to less we> because x is commonly m scatt]$4 ,sup]glacial drift is worn little or none :ile x lies on ! surface ( ! ice2 b 9 s f> z sup]glacial or englacial drift is d]iv$ f ! basal load1 x may %[ ! same evid5ces ( we> z ! basal drift itself4 ,sup]glacial drift (t5 reveals its hi/ory 9 ?is way4 ,illu/ration3 ,fig4 #bgd4--,?ick5+ ( ! upturn$ lay]s ( ice4 ,deposition ( ! ,drift4 #a4 ,b5ea? ! body ( ! ice4--,dur+ ! advance ( a glaci]1 deposition may take place bo? b5ea? ! body ( ! ice & b5ea? its end & edges4 ,deposition b5ea? ! body ( ! ice is liable to take place :]ev] ! topography favors lodgm5t1 or :]ev] ! ice is ov]load$4 ,! topography favor+ deposition is mu* ! same z t favor+ erosion1 b ! two processes are n favor$ at ! same po9t4 ,erosion is greate/ on ! 8/oss0 side ( an ob/ruction 7! side aga9/ :i* ! ice advances71 & deposition on ! lee side4 ,! ice is likely to be ov]load$ 7#a7 j beyond a place :]e conditions h favor$ ! ga!r+ ( a heavy load1 & 7#b7 :]e ! ice is rapidly ?9n+4 ,on ! :ole1 h[ev]1 ! deposition ( mat]ial b5ea? ! ma9 body ( a glaci] is mu* m ?an balanc$ by erosion 9 ! same position4 ,illu/ration3 ,fig4 #bge4--;,glaci] build+ an embankm5t4 ,s\!a/ side ( ,mc,cormick ,bay1 ,nor? ,gre5l&4 #b4 ,at ends & edges ( glaci]s4--,at & ne> ! end ( a glaci] ! conditions ( deposition are some:at diff]5t4 ,"h deposition b5ea? ! ice goes on fa/] ?an else:]e1 *iefly because ( ! m rapid melt+ & ! m rapid ?9n+ & weak5+ ( ! ice4 ,if ! end ( ! glaci] be /ation>y 9 position1 drift is be+ cont9ually br\ght to x & left !re1 = ?\gh ! end is /ation>y1 ! ice cont9ues to move4 ,if ! glaci] moves =w>d #ejj feet p] ye>1 & if its end is melt$ at ! same rate1 all ! dbris 9 ! #ejj feet ( ice :i* has be5 melt$ has be5 deposit$1 & all except t :i* has be5 wa%$ away has be5 deposit$ at & b5ea? ! end ( ! glaci]4 ,if ! end ( ! glaci] is retreat+1 ! retreat means t ! wa/e at ! end exce$s ! =w>d movem5t4 ,if ! ice advances #cjj feet p] ye>1 & is melt$ back #ejj feet 9 ! same "t1 all ! dbris c>ri$ by ! #ejj feet :i* has be5 melt$ has be5 deposit$1 & l>gely 9 ! n>r[ zone 7#bjj feet7 f :i* ! ice has rec$$4 ,ev5 9 ?is case1 !re=e1 !re is a notable t5d5cy to m>g9al accumulation4 ,if ! end ( ! glaci] is advanc+ #ejj feet p] ye> :ile x is be+ melt$ b #cjj feet1 all ! drift 9 ! #cjj feet melt$ has be5 deposit$1 & *iefly at or b5ea? ! imm$iate m>g9 ( ! ice4 ,to ! m>g9al & sub-m>g9al accumulations made 9 ?is way1 ! mat]ial c>ri$ on ! ice is add$ :5ev] ! ice is melt$ f b5ea? x4 ,?is addition is sometimes consid]able & sometimes meagre4 ,if ! edge ( ! ice is )\t mu* fluctuation 9 position1 ! mat]ial dump$ ov] its end may take ! =m ( a n>r[ ridge or b[ld]-wall 7,ges*iebe-wall74 ,if a glaci] pu%es mat]ial 9 front ( x1 ?is1 too1 becomes a "p ( ! g5]al t]m9al aggregation ( drift4 ,illu/ration3 ,fig4 #bgf4--;,embankm5t complet$4 ,ne> ! la/4 ,,types ,,( ,,mora9es4 ,! t]m9al mora9e4--,! ?ick accumulation ( drift made at ! end ( a glaci] or at ! edge ( an ice %eet1 especially :]e its end or edge is /ation>y1 or ne>ly /ation>y1 = a consid]able "t1 is ! t]m9al mora9e4 ,t "p ( ! aggregation deposit$ b5ea? ! ice is sometimes call$ ! lodge mora9e 7,figs4 #bge & #bgf2 see also ,fig4 #bce72 t c>ri$ on ! ice & dropp$ at its edge1 ! dump mora9e2 & t pu%$ be=e ! ice1 ! pu% mora9e4 ,_m mora9es m>g9al to ! ice appe> to be pu% mora9es1 :5 !y are really lodge mora9es f :i* ! ice has )drawn 7,fig4 #bgg74 ,! pu% mora9e c r>ely be di/+ui%$1 & ! dump mora9e by no means always1 aft] ! disappe>ance ( ! ice4 ,illu/ration3 ,fig4 #bgg4--;,end ( a glaci] a few miles we/ ( ,kaslo on ,lake ,koot5ai1 ,b4 ,c4 ,a lodge mora9e f :i* ! ice has )drawn1 giv+ x ! appe>ance ( a pu% mora9e4 ,x is possible t ! lodge mora9e mat]ial has be5 pu%$ up a little by re-advance ( ! ice4 7,atwood47 ,! gr\nd mora9e4--,:5 a glaci] disappe>s by melt+1 all its dbris is deposit$4 ,all ! drift deposit$ b5ea? ! advanc+ ice & all deposit$ f ! base ( ! ice dur+ its dissolution con/itutes ! gr\nd mora9e4 ,! ?ickness ( ! gr\nd mora9e is notably unequal4 ,9 g5]al1 x is ?ick] t[>d ! t]m9us ( ! glaci] & ?9n] t[>d its s\rce1 b consid]able portions ( a glaci]'s b$ are (t5 left )\t dbris :5 ! ice melts4 ,9 g5]al1 ! t]m9al mora9e is n only ?ick]1 b m irregul>ly dispos$ ?an ! gr\nd mora9e4 ,! lat]al mora9es4--,! surface lat]al mora9es ( valley glaci]s are let d[n on ! surface b5ea? :5 ! ice melts out f "u !m2 b ! lat]al mora9es 9 a valley f :i* ! ice has melt$ are n m]ely ! lat]al mora9es :i* 7 on ! glaci] at a giv5 "t4 ,!y are (t5 f> m massive ?an any :i* ev] exi/$ on ! ice itself at any "o "t 7,fig4 #bgh74 ,z a glaci] retreats1 its lat]al mora9e mat]ial is m or less bun*$4 ,?us if ! ice advances #bjj feet :ile its end is be+ melt$ back #cjj feet1 ! lat]al mora9es on ! #cjj feet melt$ are conc5trat$ into #ajj feet1 z !y are deliv]$ on to ! l& by ! melt+ ( ! ice f b5ea?4 ,if ! retreat ( ! end ( a glaci] be v sl[1 ! bun*+ may be great4 ,b ev5 ?is _c expla9 ! massiv5ess ( "s lat]al mora9es4 ,fur!rmore1 ! mat]ials ( :i* _m lat]al mora9es are compos$ are ne>ly z well worn z ^? ( ! gr\nd mora9e4 ,! massive lat]al mora9es ( :i* ?is is true are (t5 made up *iefly ( ! drift accumulat$ b5ea? ! lat]al m>g9s ( ! glaci]s4 ,?is accumulation is ! result ( ! lat]al motion ( ! ice f c5t] to side4 ,su* sublat]al accumulations are ak9 to t]m9al mora9es4 ,"s ( ! lat]al mora9es ( anci5t valley glaci]s1 su* z ^? ( ! ,u9ta1 ,wasat*1 & ,bighorn m\nta9s are sev]al hundr$ feet high1 & 9 "o case ab\t #ajjj feet4 ,9 nor!rn ,italy lat]al mora9es are said to be #aejj to #bjjj feet high4#acb ,illu/ration3 ,fig4 #bgh4--;,a lat]al mora9e f :i* ! ice has retreat$4 ,bighorn ,m\nta9s1 ,wyo4 7,blackweld]47 ,illu/ration3 ,fig4 #bgi4--;,glacial drift1 co>se & f9e toge!r4 7,geol4 ,surv4 ( ,n4 ,j47 ,mo/ ( ! mat]ial :i* 0 englacial dur+ ! transportation becomes ei!r subglacial or sup]glacial be=e deposition1 = x ord9>ily rea*es ! bottom or ! top ( ! ice be=e be+ deposit$4 ,:]e ! ends or edges ( a glaci] are v]tical or ne>ly s1 z 9 ! high arctic regions1 deposition may take place f ! englacial position directly4 ,di/9ctive nature ( glacial deposits4--,! deposits made by glaci]s are di/9ctive4 ,9 ! fir/ place ! ice does n assort its mat]ial1 & b[ld]s1 cobbles1 pebbles1 s&1 & clay are confus$ly comm+l$ 7,fig4 #bgi74 ,9 ?is respect1 ! deposits ( ice diff] notably f ^? ( wat]4 ,fur!rmore1 _m /ones ( ! drift %[ ! peculi> type ( we> :i* glaci]s inflict4 ,!y are n r\nd$ z ! /ones c>ri$ by riv]s1 ?\gh !y are notably worn4 ,_m ( !m h subangul> =ms ) plan$ & bevel$ faces1 ! planes be+ /riat$ & bruis$ 7,fig4 #bed74 ,! abs5ce ( /ratification1 ! physical het]og5eity1 & ! /riation ( at lea/ a "p ( ! /ones are among ! mo/ di/9ctive *>act]i/ics ( glacial drift4 ,a n less real ?\gh less obvi\s *>act]i/ic is ! con/itution ( ! f9e mat]ial1 = x is 9 g5]al n ! product ( rock decay1 b ( rock gr9d+4 ,! f9e mat]ial h&l$ by /reams 7except glacial /reams7 on ! o!r h&1 is usually ! product ( rock decay4 ,illu/ration3 ,fig4 #bhj4--,ro*e m\tonne1 ,victoria ,h>bor1 ,b4 ,c4 ,glaciat$ rock surfaces4--,ano!r di/9ctive m>k :i* a glaci] leaves beh9d x is ! "* ( ! surface ( ! rock on :i* ! drift re/s4 ,?is is g5]ally smoo!d by ! sev]e abrasion to :i* x has be5 subject$1 & ! smoo!d surfaces are m>k$ by grooves & /ri1 simil> to ^? on ! /ones ( ! drift 7,figs4 #bee & #bef74 ,o!r di/9ctive features ( a glaciat$ area are ! r\nd$ bosses ( rock 7ro*es m\tonnes1 ,fig4 #bhj2 see also surface ab\t ! lakes1 ,fig4 #bfa71 ! rock bas9s1 ! lakes 7,fig4 #bfa71 ponds1 & m>%es1 & ! peculi> topographies result+ f ! unequal erosion1 & ! /ill m unequal deposition ( ! drift4 ,surface b[ld]s1 (t5 unlike ! und]ly+ =mations ( rock1 & sometimes 9 peculi> & app>5tly un/able positions1 are /ill ano!r m>k ( a glaciat$ area4 ,,glacio-,,fluvial ,,"w4 ,! con/ant b unequal wa/e ( glaci]s has already be5 ref]r$ to4 ,! /reams to :i* ?is gives rise are usually lad5 ) gravel1 s& & silt d]iv$ f ! ice4 ,s9ce ! mud is (t5 light-color$1 ! /reams are sometimes describ$ z 8milky40 ,:]e ! am\nt ( mat]ial c>ri$ is great1 mu* ( x is dropp$ at a slight di/ance f ! ice1 ! co>se/ be+ dropp$ fir/4 ,glacial /reams are1 z a rule1 aggrad+ /reams1 & !re=e develop alluvial pla9s1 call$ valley tra9s 7,fig4 #bha & #bhb71 or :]e !y ent] lakes 7,fig4 #bhc71 bays1 or o!r /reams1 deltas4 ,9 its transportation1 ! riv]-borne drift is assort$2 aft] its deposition1 x is /ratifi$4 ,true glacial deposits 9 ! upp] "p ( a m\nta9 valley are1 !re=e1 (t5 cont9u$ bel[ by glacio-fluvial deposits d]iv$ f ! same s\rce4 ,illu/ration3 ,fig4 #bha4--;,alluviation by glacial /ream3 ,nicolai ,creek1 ,alaska4 7,s*rad]1 ,u4 ,s4 ,geol4 ,surv47 ,! mo/ common =m ( su* deposit is a valley tra9 7,fig4 #bha7 ( glacial wa% /ret*+ indef9itely d[n ! valley4 ,! silt1 s&1 & gravel ( su* tra9s c usually be di/+ui%$ f valley deposits ( non-glacial orig9 by ! "* ( ! mat]ial1 z mu* ( x is ! product ( gr9d+1 cru%+1 & fracture1 r ?an ( ord9>y surface decay4 ,its mat]ials are1 !re=e1 fre% & (t5 include rock mat]ial :i*1 if long expos$ at ! surface1 w\ld be decompos$ or dissolv$4 ,illu/ration3 ,fig4 #bhb4--;,alluviation by glacial /ream bel[ ,hidd5 glaci]1 ,alaska4 7,gilb]t1 ,u4 ,s4 ,geol4 ,surv47 ,:]e an ice %eet ends 9 a broad face1 z did ! anci5t cont95tal glaci]s1 num]\s /reams fl[ f x & spread _! dbris 9 front ( ! t]m9al mora9e1 =m+ a broad fr++ %eet or 8apron0 7outwa% pla97 along x4 ,:]e /reams ( consid]able size =m tunnels "u or 9 ! ice1 ^! may become m or less fill$ ) wa%1 & :5 ! ice melts ! aggrad$ *annels appe> z long ridges ( gravel & s& kn[n z esk]s 7os>s & s]p5t9e kames & kames ( au?ors4 ,see *apt] on glacial p]iod74 ,x has be5 ?\ght t simil> ridges are sometimes =m$ 9 valleys cut 9 ! ice f top to bottom1 & ev5 t !y arise f gravel & s& lodg$ 9 sup]glacial *annels4 ,! latt] at lea/ is probably r>e1 z ! surface /reams usually h high gradi5ts1 swift curr5ts1 & smoo? bottoms1 & h5ce give little opportunity = lodgm5t4 ,9 ! case ( ice-%eets1 too1 9 connection ) :i* esk]s are *iefly develop$1 !re is usually no surface mat]ial except at ! imm$iate edge1 :]e ! ice is ?9 & its lay]s upturn$4 ,at ! m\?s ( ice-tunnels or ice-*annels1 especially :]e !y end aga9/ t]m9al mora9es1 s&s & gravels are liable to be bun*$ 9 quantity1 giv+ rise1 aft] ! adjac5t ice has melt$1 to peculi> hills & holl[s ( ! knob-&-bas9 type4 ,! hills & %ort ridges are kn[n z kames 7see glacial p]iod74 ,subglacial /reams may leave wa%$ & assort$ mat]ial 9 _! tracks "u ! ice1 & ?is is sometimes buri$ "u deposits made by ! ice itself1 s t glacio-fluvial & glacial deposits are int]b$d$4 ,illu/ration3 ,fig4 #bhc4--;,delta at ,isola1 ,lake ( ,sils1 ,engad9e1 ,switz]l&4 7,reid47 ,,iceb]gs4 ,:5 glaci]s advance into wat]1 ! dep? ( :i* approa*es _! ?ickness1 _! ends are brok5 (f 7,fig4 #bhd71 & ! deta*$ masses float away z iceb]gs 7,fig4 #bhe74 ,_m ( ! b]gs are ov]turn$1 or at lea/ tilt$1 z !y set sail4 ,if ?is does n happ5 at ! outset1 x is likely to occur lat] z ! result ( ! melt+ & wave-cutt+ :i* di/urb _! equilibrium4 ,! great majority ( b]gs d n travel f> be=e los+ all trace ( /ony & e>?y dbris1 b ! f9d+ ( glacial mat]ial 9 dr$g+s f> s\? ( all glaci]s %[s t !y occasionally c>ry /ones f> f l&4 ,illu/ration3 ,fig4 #bhd4--;,end ( ,muir glaci]1 ,alaska4 7,reid47 ,,! ,,intimate ,,/ructure ,,& ,,! ,,movem5t ,,( ,,glaci]s4 ,) ! prec$+ acc\nt ( glaci]s 9 m9d1 we may return to a clos] /udy ( _! orig91 _! intimate /ructure1 & _! mode ( motion4 ,! key to ?is /udy is ! !sis t a glaci] is a mass ( cry/all9e rock--! pure/ & simple/ type ( cry/all9e rock kn[n--s9ce x is made up ( a s+le m9]al ( simple composition & r>e purity1 :i* nev] appe>s 9 a solid /ate except 9 ! cry/all9e =m4 ,! gr[? & con/itution ( a glaci]4--,! orig9 & hi/ory ( a glaci] is little m ?an ! orig9 & aggregate hi/ory ( ! cry/als t compose x4 ,! fundam5tal conception ( a glaci] is !re=e be/ obta9$ by trac+ ! gr[? ( its con/itu5t cry/als4 ,a basal fact ev] to be kept 9 m9d is t wat] 9 ! solid =m is always controll$ by cry/all9e =ces4 ,:5 x solidifies f ! vapor ( ! atmosph]e x takes ! =m ( sep>ate cry/als 7,figs4 #bhf-bia74 ,p]fect =ms are develop$ only :5 ! flakes fall quietly ?r\gh a saturat$ atmosph]e :i* all[s !m to gr[ z !y desc5d4 ,"u o!r conditions1 ! cry/als are imp]fect 9 gr[? & are mutilat$ by impact4 ,b h[ev] modifi$1 !y are always cry/als4 ,! molecules are arrang$ on ! hexagonal plan1 &1 z ! expansive p[] ( freez+ wat] %[s1 ! arrangem5t is controll$ by a /rong =ce4 ,once ! def9ite cry/all9e arrangem5t is e/abli%$1 ! molecules c be displac$ only by relatively great =ce4 ,illu/ration3 ,fig4 #bhe4--;,an iceb]g1 we/ coa/ ( ,gre5l&4 ,sn[ cry/als (t5 cont9ue to gr[ s long z !y are 9 ! atmosph]e2 b if !y pass ?r\gh an "u-saturat$ /ratum ( air or a /ratum ^: temp]ature is above #cb ,fahr41 !y suff] f evaporation or melt+4 ,:5 !y rea* ! gr\nd1 ! processes ( gr[? & decad5ce cont9ue1 & ! cry/als gr[ or dim9i% accord+ to circum/ances4 ,a glaci] is a colossal aggregation ( cry/als gr[n f sn[flakes to granules ( mu* great] sizes4 ,! microscopic /udy ( new-fall5 sn[ reveals ! mode ( *ange f flakes to granules4 ,! sl5d] po9ts & angles ( ! =m] yield to melt+ & evaporation m ?an ! m massive c5tral portions1 & ?is *ange probably illu/rates a law ( vital importance4 ,x may (t5 be se5 t ! wat] melt$ f ! p]iph]y ( a flake ga!rs ab\t its c5t]1 & if ! temp]ature be "r1 x freezes !re4 ,?is is a fir/ /ep t[>d ! pron\nc$ granulation ( sn[ :i* has la9 = "s "t on ! gr\nd4 ,if measur$ sy/ematically f day to day1 ! l>g] granules tak5 f b5ea? ! surface ( ?is co>se-gra9$ sn[ are f\nd to be gr[+4 ,9 a s]ies ( exp]im5ts#acc to det]m9e ! law ( gr[? x 0 f\nd t :5 ! temp]ature ( ! atmosph]e 0 above ! melt+-po9t ! gr[? 0 appreciably m rapid ?an :5 ! air 0 cold]1 b !re 01 on ! av]age1 an increase "u all conditions ( temp]ature4 ,a portion ( ?is av]age increase ( ! l>g] granules appe>s to come f ! dim9ution & de/ruction ( ! small] ones1 = ! total numb] ( granules /eadily dim9i%es4 ,a portion ( ! gr[? d\btless comes f ! moi/ure ( ! atmosph]e :i* p5etrates ! sn[ & ano!r portion f ! moi/ure d]iv$ f surface melt+2 b b5ea? ! surface ( a l>ge body ( sn[ ! gr[? ( ! l>ge granules is probably *iefly at ! exp5se ( ! small ones4 ,to foll[ ! process x %\ld be not$ t ! free surface ( e granule is con/antly ?r[+ (f p>ticles ( wat]-vapor 7evaporation72 t ! rate at :i* ! p>ticles are ?r[n (f is dep5d5t1 among o!r ?+s1 on ! curvature ( ! surface1 be+ great] ! %>p] ! curve2 t ! surfaces ( ! granules are at ! same "t liable to receive & reta9 molecules ?r[n f o!r granules1 & t1 o!r ?+s be+ equal1 ! ret5tion ( p>ticles also dep5ds on ! curvature ( ! surface1 ! less curv$ surface reta9+ m ?an ! %>ply curv$ "o4 ,"u ^! laws1 x is obvi\s t ! l>g] granules ( small] curvature w lose less & ga9 m1 on ! av]age1 ?an ! small] granules ( great] curvature4 ,x foll[s t ! l>g] granules w gr[ at ! exp5se ( ! small]4 ,x is also to be not$ t1 o!r ?+s be+ equal1 small granules melt m readily ?an l>ge ones1 & t :]e ! temp]ature is nicely adju/$ betwe5 melt+ & freez+1 ! small] may lose :ile ! l>g] ga94 ,illu/ration3 ,figs4 #bhf-ia4--,sn[flakes4 7,photograph$ by ,w4 ,a4 ,b5tley47 ,ano!r factor t ent]s into ! process is t ( pressure & t5sion4 ,! granules are compress$ at ! po9ts ( contact & put "u t5sion at po9ts n 9 contact1 & ! pressure & t5sion are1 on ! av]age1 likely to be relatively greate/ = ! smalle/ granules4 ,t5sion increases ! t5d5cy to evaporation & adds its effects to curvature1 & ! capill>y spaces adjo9+ ! po9ts ( contact probably favor cond5sation4 ,ice exp&s 9 cry/alliz+ & pressure r$uces ! melt+-po9t1 :ile t5sion raises x4 ,! effect ( ?is is slight 7p4 #bgf71 & x probably plays little "p 9 glacial action1 b x is to be correlat$ ) ! mu* m important fact t compression produces heat :i* may raise ! temp]ature ( ! ice to ! melt+-po9t1 :ile t5sion may r$uce ! temp]ature to or bel[ freez+4 ,!re is !re=e a t5d5cy = ! ice to melt at ! po9ts ( contact & compression1 & = ! wat] s produc$ to refreeze at adjac5t po9ts :]e ! surface is "u t5sion4 ,?is process becomes effective b5ea? a consid]able body ( sn[1 & "h ! granules gradually lose ! sph]oidal =m assum$ 9 ! e>ly /ages ( granulation & become irregul> polyh$rons int]lock$ into a m or less solid mass4 ,a ?ird factor is also to be recogniz$1 ?\gh its effectiv5ess is unkn[n4 ,"u sev]e w9d pressure1 air p5etrates por\s bodies ) appreciable facility4 ,! 8brea?+0 ( soils & ! curi\s ph5om5a ( 8bl[+-wells0 & 8bl[+-caves0 tea* u ( ! effective p5etration & extrusion ( ! air "u v>iations ( b>ometric pressure4 ,9 ! sn[-fields1 & 9 ! m granul> portions ( glaci]s ne> _! heads1 ! porosity is d\btless suffici5t to all[ ( ! appreciable p5etration ( ! atmosph]e4 ,dur+ a "p ( ! "t1 ! probable effect is ! cond5sation )9 ! ice ( moi/ure f ! air1 & dur+ ano!r "p1 evaporation f ! ice4 ,^! alt]nat+ processes are att5d$ by oscillations ( temp]ature4 ,:ile ! balance betwe5 loss & ga9 ( sub/ance may be immat]ial1 ! oscillat+ nature ( ! process & ! fluctuations ( temp]ature are probably favorable to granul> *ange4 ,:e!r ^! processes furni% an adequate explanation ( ! *anges or n1 ! obs]v$ fact is t !re are all gradations f sn[flakes & pellets into granul> nv1 & !nce into glaci] granules 7,glets*]krn]71 v>y+ 9 size up to t ( filb]ts & walnuts1 & ev5 beyond4 ,9 coh]5ce1 ^! aggregations may v>y f ! e>ly slightly coh]5t granul> /age1 :]e ! gra9s are small & sph]oidal1 to ! ice /age1 :]e ! cohesion has become /rong ?r\gh ! int]lock+ gr[?s ( ! l>ge granules4 ,ev5 :5 ! mass has become seem+ly solid ice1 suffici5t space is usually left betwe5 ! granules to give ! disp]sive reflection to light :i* imp>ts to glaci] ice its di/9ctive :iti% color4 ,! arrangem5t ( ! cry/al axes4--,! mo/ radical diff]5ce betwe5 glaci] ice & ice =m$ directly f wat] is 9 ! arrangem5t 7ori5tation7 ( ! cry/als4 ,9 ! ice =m$ on undi/urb$ wat]1 ! bases ( ! cry/als are at ! surface & _! pr9cipal axes are v]tical1 z %[n by ,mgge4#acd ,z !y gr[1 ! cry/al prisms ext5d d[nw>ds4 ,?is gives a column> or prismatic /ructure to ! ice1 well se5 :5 x is 8honeycomb$0 by p>tial melt+4 ,9 ! glaci]1 on ! o!r h&1 ! cry/als1 />t+ f sn[flakes1 h _! axes turn$ 9 v>i\s directions accord+ to ! accid5ts ( _! fall2 & z ! sn[ develops into ice1 ! pr9cipal axes ( ! cry/als cont9ue to lie 9 all directions4 ,h5ce glaci] ice1 unlike pond ice1 _c usually be split along def9ite planes1 except :]e cleavage planes are subsequ5tly develop$ by extrane\s ag5cies4 ,illu/ration3 ,fig4 #bia;a4 ,fig4 #bia;b4 ,fig4 #bia;c4 ,figures to illu/rate ! me?od ( de=mation ( ice cry/als4 ,:ile ! cry/als ( a glaci] usually h _! pr9cipal axes 9 v>i\s directions1 !re appe>s to be a t5d5cy = !m to approa* p>allelism 9 c]ta9 positions1 especially 9 ! basal p>ts ( a glaci] ne> its t]m9us4 ,obs]vations on ?is po9t are n s full & critical z c\ld be desir$1 b x is probable t ! p>allel ori5tation is p>tly g5]al1 & due to ! v]tical pressure ( ! ice1 & p>tly special & local1 & connect$ ) ! %e>+ planes & foliation4 ,! be>+ ( ?is p>tial p>allelism ( ! cry/als on %e>+ & foliation is suppos$ to reside 9 ! fact t a cry/al ( ice is made up ( a s]ies ( plates arrang$ at "r angles to ! pr9cipal axis ( ! cry/al4 ,^! plates may be lik5$ to a pile ( c>ds1 ! pr9cipal axis be+ repres5t$ by a l9e v]tical to !m4 ,if a cube be cut f a l>ge cry/al ( ice1 x w behave mu* l a cube cut f ! pile ( c>ds4 ,if ! cube be s plac$ t its plates are horizontal 7,fig4 #bia;a71 & if x be re/$ on supports at two edges & heavily weight$ 9 ! middle1 x w sag1 ! plates slid+ slightly ov] "o ano!r s z to give oblique ends1 b 9 ?is case ! cube (f]s consid]able resi/ance to de=mation4 ,if ! cube be s plac$ t ! plates /& on edge1 ea* rea*+ f support to support 7,fig4 #bia;b71 x w (f] v great resi/ance to de=mation2 b if ! plates be v]tical & transv]se to ! l9e jo9+ ! supports1 z 9 ,fig4 #bia;c1 ! middle portion w sag "u v mod]ate weight+ by ! slid+ ( ! plates on "o ano!r1 & 9 a comp>atively %ort "t ! middle portion may be pu%$ entirely out1 divid+ ! cube4 ,^! prop]ties h be5 demon/rat$ by ,mc,connel#ace & ,mgge1 & !y appe> to ?r[ light on c]ta9 phases ( ! action ( glaci]s t are mo/ pron\nc$ 9 _! basal p>ts1 & are be/ illu/rat$ 9 arctic glaci]s4 ,! ,probable ,fundam5tal ,elem5t 9 ,glacial ,motion4 ,melt+ & freez+4--,x has already be5 %[n 7p4 #bgi7 t ! initial or fundam5tal cause ( glacial motion mu/ be op]ative at ! heads ( glaci]s :]e ! temp]ature is l[e/ & ! mat]ial mo/ loosely granul>4 ,9 ?is condition1 !re is reason to believe t motion takes place betwe5 ! gra9s1 r ?an by _! di/ortion ?r\gh ! displacem5t ( _! lam94 ,! fact t ! granul> /ructure is n de/roy$1 z x w\ld be by ! indef9ite slid+ ( ! cry/al plates ov] ea* o!r1 su/a9s ?is view4 ,! inf]5ce is t ! glid+ planes play a notable rle 9 glacial movem5t only 9 ! basal p>ts ( ! l[] ends ( glaci]s1 :]e ! greate/ ?ru/s are develop$1 & :]e ! granules h become l>ge/ & mo/ completely int]lock$4 ,at ! heads ( glaci]s1 :]e motion is initiat$1 !re may be great d[nw>d pressure1 b n vigor\s ?ru/s f beh9d1 & probably only mod]ate ?ru/s develop$ )9 ! body itself4 ,!re seems !re=e no escape f ! conclusion t ! primal cause ( glacial motion is "o :i* may op]ate ev5 "u ! relatively l[ temp]atures1 ! relatively dry conditions1 & ! relatively granul> textures :i* affect ! heads ( glaci]s4 ,^! consid]ations lead to ! view t movem5t takes place by ! m9ute individual movem5ts ( ! gra9s ^u "o ano!r4 ,:ile !y are 9 ! sph]oidal =m1 z 9 ! nv1 ?is w\ld n seem to be at all difficult4 ,!y may rotate & slide ov] ea* o!r z ! weight ( ! sn[ increases2 b z !y become int]lock$ by gr[?1 bo? rotation & slid+ mu/ app>5tly enc\nt] m resi/ance4 ,! am\nt ( rot>y motion requir$ ( an individual granule is1 h[ev]1 surpris+ly small1 & ! melt+s & refreez+s incid5t to %ift+ pressures & t5sions1 & to ! gr[? ( ! granules1 seem adequate to meet ! requirem5ts4 ,9 ord] to acc\nt = a movem5t ( ?ree feet p] day 9 a glaci] six miles long1 ! mean motion ( ! av]age granule relative to its neighbor w\ld be1 r\ndly1 ( its own diamet] p] day1 or "o diamet] 9 #aj1jjj days2 9 o!r words1 x w\ld *ange its relations to its neighbors to ! ext5t ( its diamet] 9 ab\t ?irty ye>s4 ,a *ange ( s great sl[ness "u ! conditions ( granul> alt]ation c sc>cely be ?\ght incr$ible1 or ev5 improbable1 9 spite ( ! int]lock+ :i* ! granules may develop4 ,! movem5t is suppos$ to be p]mitt$ *iefly by ! tempor>y passage ( m9ute portions ( ! granules into ! fluid =m at ! po9ts ( greate/ compression1 ! transf] ( ! moi/ure to adjo9+ po9ts1 & its resolidification4 ,! po9ts ( greate/ compression are obvi\sly j ^? ^: yield+ mo/ promotes motion1 & a successive yield+ ( ! po9ts t come 9 succession to oppose motion mo/ 7& ?us to receive ! greate/ /resses7 p]mits cont9u\s motion4 ,x is m]ely necess>y to assume t ! gravity ( ! accumulat$ mass is suffici5t to produce ! m9ute tempor>y liquefaction at ! po9ts ( greate/ /ress1 ! result be+ accompli%$ n s mu* by ! l[]+ ( ! melt+-po9t z by ! developm5t ( heat by pressure4 ,illu/ration3 ,fig4 #bib4--,portion ( ! ea/ face ( ,b[do9 glaci]1 ,nor? ,gre5l&1 %[+ oblique upw>d ?ru/1 ) %e>4 ,?is conception ( glacial 8fl[age0 involves only ! mom5t>y liquefaction ( m9ute portions ( ! mass1 :ile ! ice z a :ole rema9s rigid1 z its cry/all9e nature requires4 ,in/ead ( assign+ a sl[ visc\s fluidity l t ( asphalt to ! :ole mass1 :i* seems inconsi/5t ) its cry/all9e "*1 x assigns a free fluidity to a succession ( p>ticles t =m only a m9ute fraction ( ! :ole at any in/ant4 ,?is conception is consi/5t ) ! ret5tion ( ! granul> condition ( ! ice1 ) ! het]og5e\s 79 ! ma97 ori5tation ( ! cry/als1 ) ! rigidity & brittl5ess ( ! ice1 & ) its /rictly cry/all9e "*1 a "* :i* a visc\s liquid does n possess h[ev] mu* its high viscosity may make x resemble a rigid body4 ,accumulat$ motion 9 ! t]m9al "p ( a glaci]4--,h[ev] slight ! relative motion ( "o granule on its neighbor1 ! granules 9 any "p ( a glaci] p>take 9 ! accumulat$ motion ( all p>ts ne>] ! s\rce1 & h5ce all are ?ru/ =w>d4 ,h]e9 appe>s to lie ! di/9ctive nature ( glacial movem5t4 ,ea* "p ( a /ream ( wat] feels ! hydro/atic pressure ( neighbor+ p>ts 7!oretically equal 9 all directions7 & ! mom5tum ( motion1 b n ! rigid ?ru/ ( ! mass beh9d4 ,lava /reams are good types ( visc\s fluids fl[+ 9 masses comp>able to ^? ( glaci]s & on simil> slopes1 &1 9 _! la/ /ages1 at simil> rates1 b _! special modes ( fl[ & _! effects on ! sides & bottoms ( _! pa?s are radically diff]5t f ^? ( glaci]s4 ,=ceful abrasion1 & p>ticul>ly ! rigid hold+ ( imb$d$ /ones :ile !y score & groove ! rock b5ea?1 is unkn[n 9 lava /reams & is sc>cely conceivable4 ,!re is1 s f> z we "k1 no exp]im5tal or natural evid5ce t any typical visc\s body 9 fl[+ ov] a rugose bottom deta*es & picks up fragm5ts & holds !m z grav+ tools 9 its base s fix$ly z to cut deep1 long1 /raight grooves 9 ! h>d bottom ov] :i* x fl[s4 ,x w\ld seem t compet5cy to d ?is peculi> class ( "w1 :i* is di/9ctive ( glaci]s1 %\ld be demon/rat$ be=e ! visc\s !ory ( glacial movem5t is accept$ z ev5 a good work+ hypo!sis4 ,some:at 9 contra/ ) visc\s movem5t1 x is conceiv$ t a glaci] is ?ru/ =w>d rigidly by int]nal elongation1 %e>s =cibly ov] its sides & bottoms1 & leaves its di/9ctive m>ks ^u !m4 ,illu/ration3 ,fig4 #bic4--,%e>+ plane well def9$4 ,a ,spitsb]g5 glaci]4 7,hamb]g47 ,auxili>y ,elem5ts4 ,%e>+4--,9 ! l[] portion ( a glaci] :]e normally ! ?ru/s are greate/1 ! granules fewe/1 & _! int]lock+ mo/ intimate1 %e>+ takes place )9 ! ice itself4 ,?is is illu/rat$ by ! accompany+ ,figs41 #bib-bie4 ,! %e>+ results 9 ! foliation ( ! ice & 9 ! =c+ ( dbris betwe5 ! %e>$ lay]s4 ,?us ! ice becomes load$ 9 a special englacial or baso-englacial fa%ion1 z previ\sly m5tion$ & illu/rat$ 9 ,fig4 #bfh4 ,)9 ! zone ( %e>+1 x is probable t ! glid+ planes ( ! cry/als come into effective function4 ,x is ?\ght t ! comb9$ effect ( ! v]tical pressure1 ! =w>d ?ru/1 & ! basal drag ( ! ice1 may be to increase ! numb] ( granules ^: glid+ planes are p>allel to ! glaci]'s bottom4 ,at any rate1 ,drygalski reports#acf t !re is a t5d5cy to su* an arrangem5t 9 ! basal portion ( ! ,gre5l& glaci]s at _! bord]s4 ,x is conceiv$ t :]e /rong ?ru/s are br\ght to be> ^u su* a mass ( granules1 ^? ^: glid+ planes are p>allel to ! direction ( ?ru/ are /ra9$ ) suffici5t int5sity to cause ! plates to slide ov] ea* o!r1 :ile ^? :i* are n p>allel to ! direction ( ?ru/ are ei!r rotat$ into p>allelism--:5 !y also yield--or are press$ aside out ( ! plane ( %e>4 ,z previ\sly not$1 %e>+ is obs]v$ to occur *iefly :]e ! ice bel[ ! plane ( %e>+ is protect$ m or less f ! =ce ( ! ?ru/4 ,x p]haps also occurs :]e ! basal ice becomes s ov]load$ ) dbris t x is incapable ( ready movem5t4 ,illu/ration3 ,fig4 #bid4--,portion ( ! lat]al m>g9 ( a ,nor? ,gre5l& glaci]4 ,%[s upturn+ ( ! lay]s at ! base1 ! cleanness ( ! ice above ! bottom1 &1 possibly1 %e>+4 ,x is also probable t %>p diff]5tial /ra9 & %e>+ are develop$ at ! level :]e ! surface-wat] ( ! w>m season1 desc5d+ into ! ice1 rea*es ! zone ( freez+4 ,! exp&+ ( ! freez+ wat] at ! upp] limit ( ! cold zone may cause ! lay] exp&$ by x to %e> ov] t bel[4 ,z ! level ( freez+ is l[]$ ) ! advance ( ! w>m season1 ! zone ( %e>+ also s9ks4 ,?is may be reg>d$ z an auxili>y ag5cy ( %e>+1 ( application to a special horizon4 ,high temp]ature & wat]4--,9 ! zone ( wa/e1 a high] temp]ature & m wat] l5d _! aid to ! fundam5tal ag5cies ( movem5t1 & !re is ne$ = ^! aids to promote a proportionate movem5t1 = "h ! granules are m intimately int]lock$ & ! ice m compact & inh]5tly m solid & rigid4 ,! av]age temp]ature is1 h[ev]1 ne> ! melt+-po9t 7p4 #bgf71 & dur+ ! w>m season ! ice is ba!d 9 wat] s t ! necess>y *anges 9 ! cry/als are facilitat$1 & movem5t app>5tly takes place ev5 m readily ?an 9 ! m op5 granul> portion ( l[] temp]ature & dry] /ate4 ,! extraord9>y movem5ts ( c]ta9 tongues ( ice 9 "s ( ! great fiords ( ,gre5l& are probably due to ! conv]g5ce ( v ?ick sl[-mov+ ice f ! int]ior into bas9s lead+ d[n to ! fiords4 ,into ! same bas9s a l>ge am\nt ( surface-wat] is conc5trat$ at ! same "t1 ) ! result t ! ?ick ice1 ba!d ) wat] & hav+ a high gradi5t1 develops unusual velocity dur+ ! w>m season4 ,illu/ration3 ,fig4 #bie4--,lat]al m>g9 ( a ,nor? ,gre5l& glaci]1 ,+lefield ,gulf region4 ,! ov]hang+ edges ( ! successive lay]s are n altoge!r ! result ( %e>4 ,!y are due 9 "p at lea/ to diff]5tial melt+ along ! l9es :]e dbris comes to ! surface4 ,! dbris planes may be %e> planes4 ,applications4--,by a /udi\s consid]ation ( ! cop]ation ( ! auxili>y ag5cies ) ! fundam5tal ones1 ! peculi>ities ( glacial movem5t may app>5tly be expla9$4 ,9 regions ( int5se cold1 :]e a dry /ate & l[ temp]ature prevail1 z 9 ! he>t ( ,gre5l&1 ! sn[-ice mass may accumulate to extraord9>y ?icknesses1 = ! burd5 ( movem5t seems to be ?r[n almo/ :olly ^u compression1 ) ! slight aid ( molecul> *anges due to int]nal evaporation & alli$ ineffici5t processes4 ,s9ce ! temp]ature 9 ! upp] "p ( ! ice is v adv]se 7see p4 #bgg71 ! compression mu/ be great be=e x becomes effective 9 melt+ ! ice1 & h5ce ! great ?ickness ( ! mass antec$5t to mu* motion4 ,simil> conditions m or less affect ! heads ( alp9e glaci]s1 ?\gh "h ! high gradi5ts favor motion ) less] ?icknesses ( ice2 b 9 ! l[] rea*es ( alp9e glaci]s1 :]e ! temp]atures are ne> ! melt+-po9t1 & ! ice is ba!d 9 wat]1 movem5t may take place 9 ice :i* is ?9 & compact4 ,if ! views "h pres5t$ are correct1 !re is also1 ne> ! end or edge ( a glaci]1 ! cop]ation ( rigid ?ru/ f beh9d ) ! t5d5cy ( ! mass to move on its own acc\nt4 ,! latt] is controll$ by gravity1 & con=ms 9 its results to laws ( liquid fl[4 ,! =m] is a d]iv$ factor1 & is a me*anical ?ru/4 ,?is ?ru/ is diff]5t f ! pressure ( ! upp] "p ( a liquid /ream on ! l[] "p1 because x is transmitt$ ?r\gh a body ^: rigidity is effective1 :ile ! latt] is transmitt$ on ! hydro/atic pr9ciple ( equal pressure 9 all directions4 ,corroborative ,ph5om5a4 ,! conception ( ! glaci] & its movem5t "h pres5t$ expla9s "s ( ! anomalies t o!rwise seem p>adoxical4 ,:ile a glaci] 9 a s5se fl[s ov] a surface1 x (t5 cuts long1 deep furr[s 9 firm rock4 ,x is difficult to expla9 ?is if ! ice be s yield+ z to fl[ "u its own weight on a surface :i* is almo/ flat4 ,if ! mass is really visc\s1 its hold on its imb$d$ dbris %\ld also be visc\s1 & a b[ld] 9 ! bottom %\ld be rotat$ 9 ! yield+ mass :5 its l[] po9t cat*es on ! rock b5ea?1 in/ead ( be+ firmly held :ile a deep groove is cut4 ,?is is m to ! po9t s9ce visc\s fluids fl[ by a p>tially rot>y movem5t4 ,if1 on ! o!r h&1 ! ice is always a rigid body :i* yields only z its int]lock+ granules *ange _! =m by loss & ga91 a rigid hold on ! imb$d$ rock at "s times1 & a yield+ hold at o!rs1 is intelligible1 = on ?is view ! nature ( its hold is dep5d5t on ! temp]ature & dryness ( ! ice4 ,/ones 9 ! base ( a glaci] may be held ) v great rigidity :5 ! ice is dry1 scor+ ! bottom ) mu* =ce1 :ile !y may be rotat$ ) relative ease :5 ! ice is wet4 ,9 %ort1 ! relation ( ! ice to ! b[ld]s 9 its bottom v>ies radically accord+ to its dryness & temp]ature4 ,a dry glaci] is a rigid glaci]4 ,a dry glaci] is necess>ily cold1 & a cold glaci] is necess>ily dry4 ,on ! view "h pres5t$1 a glaci] %\ld be m rigid 9 w9t] ?an 9 summ]1 & ! :ole ?ickness ( ! glaci] %\ld exp]i5ce ?is rigidity *iefly at ! ends & edges1 :]e ! relative ?9ness ( ! ice p]mits ! l[ temp]ature to rea* its bottom4 ,! motion 9 ^! p>ts dur+ ! w9t] is1 !re=e1 v small4 ,9 ?is view may also be f\nd an explanation ( ! movem5t ( glaci]s = consid]able di/ances on upw>d slopes1 ev5 :5 ! surface z well z ! base is incl9$ backw>ds4 ,s f> does ?is g t sup]glacial /reams sometimes run = "s di/ance backw>ds1 i4e4 t[>d ! heads ( ! glaci]s1 :ile 9 o!r places surface-wat]s are collect$ into ponds & lakelets4 ,su* a slope ( ! surface ( ice is n difficult to und]/& if ! movem5t be due to ?ru/ f beh9d1 or if x be occasion$ by int]nal cry/all9e *anges act+ ^u a rigid body2 b x mu/ be reg>d$ z v rem>kable if ! movem5t be t ( a fluid body1 no matt] h[ visc\s1 = ! l5g? ( ! acclivity is sometimes sev]al times ! ?ickness ( ! ice4 ,crevass+ & o!r evid5ces ( brittl5ess & rigidity f9d a ready elucidation "u ! view t ! ice is a really solid body at all times1 & t its app>5t flu5cy is due to ! mom5t>y fluidity ( small portions ( ! mass assum$ 9 succession z compression dem&s4 ,9 addition to ! consid]ations already adduc$1 x may be urg$ t a glaci] does n fl[ z a /iff liquid because its granules are n habitually drawn out into elongat$ =ms1 z are cavities 9 lavas & pla/ic lumps 9 visc\s bodies4 ,fl[age l9es comp>able to ^? 9 lavas are unkn[n 9 glaci]s4 ,all ?is is /rictly consi/5t ) our prim>y !sis1 t a glaci] is a cry/all9e rock ( ! pure/ & simple/ type1 & t x nev] has o!r ?an ! cry/all9e /ate4 ,?is /rictly cry/all9e "* is incompatible ) visc\s liquidity4 ,o!r ,views ( ,glaci] ,motion4#acg ,:ile ^! views ( glacial motion seem to u to be/ accord ) ! kn[n facts1 !y are n to be reg>d$ z e/abli%$ 9 sci5tific op9ion1 or z ! views mo/ commonly held4 ,! mode ( glacial motion has long be5 a moot$ "q1 & is /ill s reg>d$4 ,! ma9 alt]native int]pretations t h be5 ent]ta9$ are ! foll[+3 7#a7 ,9 ! e>ly days ( glacial /udies ,de ,saussure ?\ght t glaci]s slid bodily on _! b$s2 7#b7 ,*>p5ti] & ,agassiz ref]r$ ! movem5t to ! expansion ( desc5d+ wat] freez+ )9 ! glaci]2 7#c7 ,r5du & ,=bes1 foll[$ by _m1 p]haps mo/1 mod]n writ]s1 believ$ ice to be visc\s1 & t 9 suffici5tly l>ge masses x fl[s "u ! influ5ce ( its own weight1 l pit* or asphalt2 7#d7 ,o!rs1 realiz+ ! fundam5tal diff]5ce betwe5 cry/all9e ice & a true visc\s body1 h fall5 back on a vague notion ( pla/icity :i* sc>cely am\nts to a def9ite hypo!sis at all2 7#e7 ,tyndall urg$ t ! movem5t 0 accompli%$ by m9ute repeat$ fractur+ & regelation1 appeal+ to ! fact t brok5 pieces ( ice slightly press$ toge!r at melt+ temp]atures freeze toge!r1 b neglect+ ! fact t ?is w\ld de/roy ! integrity ( ! cry/als2 7#f7 ,moseley assign$ ! movem5t to a bodily expansion & contraction ( ! glaci]1 analog\s to ! creep+ ( a mass ( lead on a ro(2 7#g7 ,james ,?ompson demon/rat$ t pressure l[]s ! melt+-po9t1 & :ile ?is effect is s small z probably to be ineffectual1 x is correlat$ ) ! v important fact t compression may cause melt+1 :i* is n ! case 9 mo/ o!r rocks4 ,he recogniz$ t "u pressure p>tial liquefaction took place1 t ! wat] s lib]at$ might be refroz5 z x escap$ f pressure1 & appe>s to h reg>d$ ?is z a vital factor2 7#h7 ,croll held t ! movem5t 0 due to a consecutive s]ies ( molecul> *anges some:at l ! *a9 ( *emical comb9ations 9 electrolysis2 7#i7 ,hugi1 ,eli de ,beaumont1 ,b]t91 ,=el1 & o!rs ?\ght t ! gr[? ( ! granules 0 ! lead+ factor 9 ! ice movem5t2 7#aj7 ,mc,connel & ,mgge h made ! glid+ planes ( ! ice cry/als s]ve an important function 9 glacial movem5t4 ,x w be se5 t ! pr9ciple ( p>tial liquefaction = :i* ,?ompson laid ! basis1 ! cry/allization ( desc5d+ wat]1 urg$ by ,*>p5ti] & ,agassiz1 & ! granul> gr[? on :i* ,hugi1 ,beaumont1 ,=el1 & o!rs f\nd$ _! hypo!ses1 are incorporat$ 9 ! view already pres5t$4 ,probably ! ag5cies on :i* "s ( ! o!r views are bas$ may also be p>ticipants 9 produc+ glacial motion1 sometimes z incid5tal factors1 & sometimes p]haps z important ones1 = "u diff]5t conditions1 diff]5t ag5cies may play rles ( v>y+ importance4 ,= example1 9 go+ ov] ! br9ks ( precipices ( suffici5t height1 glaci]s break into fragm5ts :i* are re-cem5t$ bel[1 & ! 8recon/ruct$0 glaci] moves on z be=e4 ,"h fracture & regelation are evid5t4 ,! movem5t ( ! glid+ planes ( ! ice cry/als ov] ea* o!r1 :i* has be5 look$ ^u z a special k9d ( viscoid movem5t1 probably plays a l>ge "p 9 ! %e>+ movem5ts 9 c]ta9 cases4 ,b nei!r ( ^! is probably a l>ge factor 9 ord9>y glacial movem5t1 & x seems highly improbable t any ( !m are ess5tial factors 9 ! prim>y movem5ts 9 ! sn[-fields :]e glacial action beg9s4 ,,*apt] ,,vi4 ,,! ,,"w ,,( ,,! ,,ocean4 ,! g5]al facts conc]n+ ! dep? ( ! ocean & ! di/ribution ( its wat] h be5 giv5 on a prec$+ page 7p4 #h71 & ! orig9 ( ! ocean & ! ocean bas9s is discuss$ 9 ! second volume4 ,?is *apt] has to d prim>ily ) ! processes n[ go+ on 9 ! sea & its bord]s1 9 s f> z !y are ( importance 9 ! int]pretation ( geologic hi/ory4 ,! /udy ( ^! processes is prefac$ by a few words conc]n+ ! am\nt & composition ( ! sea-wat]1 ! life ( ! ocean1 & ! topography ( its b$4#ach ,volume & composition4--,e #ajjj p>ts ( sea-wat] conta9 ab\t #cd4dj p>ts by weight ( m9]al matt] 9 solution4 ,! pr9cipal solids1 acids1 & bases1 comb9$ accord+ to ! pr9ciples laid d[n by ,dittm>1 are %[n 9 ! foll[+ table3#b ,*loride ( sodium #gg4geh ,*loride ( magnesium #aj4hgh ,sulphate ( magnesium #d4gcg ,sulphate ( calcium #c4fjj ,sulphate ( potassium #b4dfe ,bromide ( magnesium #j4bag ,c>bonate ( calcium #j4cde ------- ,total salts #ajj4jjj ,express$ 9 t]ms ( tons p] cubic mile ( sea-wat]1 ! composition is z foll[s3#aci ,tons p] ,cubic ,mile4 ,*loride ( sodium 7,na,cl7 #aag1dcd1jjj ,*loride ( magnesium 7,mg,cl7 #af1dbh1jjj ,sulphate ( magnesium 7,mg,s,o7 #g1aed1jjj ,sulphate ( calcium 7,ca,s,o7 #e1dcg1jjj ,sulphate ( potassium 7,k,,s7 #c1gbc1jjj ,bromide ( magnesium 7,mg,br7 #cbh1jjj ,c>bonate ( calcium 7,ca,c,o7 #eba1jjj ----------- ,= sea-wat]1 total dissolv$ matt] #aea1jbe1jjj ,aside f ! +r$i5ts %[n 9 ! above tables1 ! pres5ce ( ! foll[+ has be5 prov$3 iod9e1 fluor9e1 phosphorus1 silicon1 boron1 silv]1 lead1 copp]1 z9c1 cobalt1 nickel1 iron1 manganese1 alum9um1 b>ium1 /rontium1 ars5ic1 li?ium1 csium1 rubidium1 & gold4 ,oxyg51 nitrog51 & c>bonic acid gas are also pres5t 9 quantity4 ,! am\nt ( c>bonic acid is e/imat$ to be #ah times z great z 9 ! atmosph]e4#adj ,! am\nt ( sea-wat] is e/imat$ by ,murray at #cbc1gbb1aej cubic miles1#ada or ab\t #ae times ! volume ( ! l& above sea-level4 ,! volume & composition ( ! sea-wat] be+ kn[n1 ! am\nt ( m9]al matt] :i* x conta9s may be readily calculat$4 ,assum+ ! av]age specific gravity ( ! m9]al matt] 9 solution to be #b4e1 ! #c4e by weight becomes #a4d by volume1 & #a4d ( #cbc1gbb1aej cubic miles is #d1ecb1aaj cubic miles4 ,?is !n repres5ts ! aggregate volume ( m9]al matt] 9 ! sea if x 7 precipitat$ & compact$ s z to h an av]age specific gravity ( #b4e4 ,assum+ ! av]age dep? ( ! sea to be #bjgf fa?oms 7#ab1def feet71 z giv5 by ,murray1 ! m9]al matt] 9 solution1 if precipitat$1 w\ld cov] ! ocean bottom to a dep? ( ab\t #age feet4 ,assum+ ! area ( ! l& to be to t ( ! sea z #bh to #gb1 ?is am\nt ( m9]al matt] w\ld make a lay] ab\t #dej feet deep ov] ! l&4 ,its am\nt is equal to ab\t #bj ( t ( all l&s above sea-level1 & x falls b little %ort ( t 9 all l&s bel[ #fjj feet 9 altitude4 ,if x 7 precipitat$ & conc5trat$ 9 ! %all[ wat]s ab\t ! bord]s ( ! l&s1 x w\ld fill ! sea out to ! dep? ( ab\t #djjj feet1 & w\ld dim9i% its area by "s #ai1jjj1jjj to #bj1jjj1jjj squ>e miles1 an area :i* is m ?an ( ! pres5t l& surface4 ,9 o!r words1 if ! m9]al matt] 9 ! sea-wat] 7 precipitat$ & conc5trat$ 9 ! %all[ wat]s ab\t ! l&s1 x w\ld re/ore ! cont95tal %elves to ! l& areas1 & add an almo/ equal area beyond4 ,^! comp>isons may p]haps help to give "s idea ( ! am\nt ( m9]al matt] 9 solution 9 ! sea1 b !y give no m ?an a h9t ( ! importance ( ! solv5t p[] ( wat] 9 ! g5]al processes ( rock decay1 = mo/ ( ! sub/ances c>ri$ to ! sea 9 solution by riv]s are extract$ f ! wat] ab\t z rapidly z !y are suppli$4 ,?us calcium c>bonate is ab\t tw5ty times z abundant z sodium *loride 9 riv]-wat]1#adb b is only z abundant 9 sea-wat]4 ,! total riv] dis*>ge into ! sea is e/imat$ at #febd cubic miles ( wat] p] ye>4#adc ,?is wat] is e/imat$ to c>ry to ! sea annually ab\t half a cubic mile ( m9]al matt] 9 solution4 ,at ?is rate x w\ld take ab\t #i1jjj1jjj ye>s = ! /reams to br+ to ! sea an am\nt ( m9]al matt] equal to t x n[ conta9s1 b ! proportions ( ! +r$i5ts w\ld be v diff]5t4 ,! sodium *loride makes up ab\t #b4d ( ! m9]al matt] 9 riv]-wat] & ne>ly #gh ( ! m9]al matt] ( ! sea4 ,at ?is rate x w\ld take ne>ly #cjj1jjj1jjj ye>s = ! salt ( ! sea to h be5 contribut$ by ! riv]s4 ,x is n to be und]/ood1 h[ev]1 t ?is figure indicates ! age ( ! ocean4 ,! salt is n all br\ght 9 by ! riv]s2 ! riv]s h probably n always contribut$ at ! pres5t rate2 & mu* salt once 9 ! sea has be5 precipitat$4 ,nev]!less ! above figure gives "s sugge/ion z to ! ord] ( magnitude ( ! figures :i* repres5t ! age ( ! ocean4 ,9 contra/ ) ! salt1 ! am\nt ( calcium c>bonate 9 ! sea is s small t at _! pres5t rate ( contribution1 x w\ld be br\ght to ! sea by riv]s 9 ab\t #fb1jjj ye>s4 ,topography ( b$4--,! g5]al relations ( ocean bas9s to cont95ts are sugge/$ by ,fig4 #bif4 ,! bord]s ( ! cont95tal plat=ms are cov]$ by ! epicont95tal sea1 :ile ! abysmal sea occupies ! ocean bas9s prop]4 ,f ! figure x is se5 t an ocean bas9 is pron\nc$ly convex upw>d1 & s dep>ts z widely z may be f ! curr5t notion ( ! homely ut5sil f :i* x is nam$4 ,only :5 x is rememb]$ t a level surface 7on ! e>?7 is "o :i* has ! mean curvature ( ! e>?1 & t ! deep] p>ts ( ! ocean bas9 are well bel[ ! mean sph]e level1 does ! curr5t "n seem ju/ifi$4#add ,! figure also %[s t ! dep? ( an ocean bas9 is slight comp>$ ) ! radius ( ! e>?4 ,! b$ ( ! ocean1 l ! face ( ! l&1 is affect$ by elevations & depressions1 & its deepe/ po9ts are ab\t z f> bel[ its surface z ! highe/ m\nta9s are above x4 ,!re are areas ( ! sea bottom :i*1 z a :ole1 may be comp>$ to ! pla9s ( ! l&1 & o!rs :i* may be lik5$ to plateaus1 & ! l9es ( gradation betwe5 !m are z indi/9ct z !y (t5 are on ! l&4 ,!re are m\nta9 peaks1 *iefly ( volcanic orig91 & depressions comp>able to ! great bas9s on ! l&4 ,b ap>t f ^! g5]al features1 !re is little 9 common betwe5 ! topography ( ! sea bottom & t ( ! l&4 ,m\nta9 sy/ems are1 = ! mo/ "p1 abs5t1 ?\gh c]ta9 isl&s1 l ,cuba & "s ( its associates1 may be reg>d$ z ! cre/s ( sy/ems :i* are *iefly subm]g$4 ,if ! wat] 7 drawn (f f ! ocean's b$ s t x c\ld be se5 z ! l& is1 its mo/ impressive feature w\ld be its monotony4 ,! famili> hills & valleys :i*1 9 all _! multitud9\s =ms1 give ! l& surface its mo/ *>act]i/ic features are ess5tially abs5t4 ,a l>ge "p ( its surface w\ld be f\nd to be s ne>ly flat t ! eye w\ld n detect its dep>ture f plan5ess4 ,illu/ration3 ,fig4 #bif4--;,g5]al relations ( ocean bas9s to ! li?osph]e4 ,lat4 #bj ,s4 ,dep? ( ! wat] 7black7 & height ( l& exagg]at$ t5 times4 7,data f ,murray1 ,scot4 ,geogr4 ,mag41 ,vol4 ,,xv1 #ahii47 ,! reason = ?is pr(\nd diff]5ce is readily f\nd4 ,on ! l&1 ! dom9ant processes :i* %ape ! details ( ! surface are degradational1 & ?\gh ! f9al result ( degradation is flatness 7base-level71 ! imm$iate result is relief1 &1 mo/ commonly1 relief ( ! hill-&-valley type4 ,9 ! sea1 ! dom9ant processes are aggradational1 & t5d to monoton\s plan5ess4 ,di/ribution ( m>9e life4--,m>9e life has be5 ( su* importance 9 ! hi/ory ( ! e>? t ! elem5t>y facts conc]n+ its di/ribution & ! pr9ciples :i* control x are "h recall$4 ,! di/ribution ( m>9e life is influ5c$ by _m factors1 *ief among :i* are temp]ature & dep? ( wat]4 ,n only is life m abundant 9 ! w>m] p>ts ( ! ocean ?an 9 ! cold]1 b ! species inhabit+ cold wat]s are diff]5t f ^? 9 w>m1 & few species range ?r\gh great v>iations4 ,_m =ms ( life are re/rict$ to %all[ wat]4 ,_m m1 especially ^? :i* d n live on ! bottom1 swim ab\t freely )\t ref]5ce to ! dep? ( ! wat] b5ea? !m1 :ile relatively few are re/rict$ to great dep?s4 ,_m species are also influ5c$ by ! sal9ity ( ! wat]1 :i* v>ies notably along coa/s :]e ! fre% wat]s f ! l& are dis*>g$2 by ! "* ( ! s$im5t at ! bottom1 "s species pref]r+ mud1 o!rs s&1 & o!rs gravel2 by ! movem5t ( ! wat]s1 "s species pref]r+ /ill wat]s & o!rs r\gh2 & "s species by ! abundance & nature ( ! food-supply1 & by rival & ho/ile species4 ,subject to ! exceptions det]m9$ by temp]ature1 etc41 plant life ab\nds 9 %all[ wat] out to dep?s ( #ajj fa?oms or s1 & is f\nd 9 abundance at ! surface :]e ! dep? is mu* great]4 ,animal life ab\nds 9 %all[ wat]1 bo? at ! bottom & above x1 out to dep?s ( #bjj or #cjj fa?oms1 & occurs 9 great pr(usion 9 ! surface-wat]s ( temp]ate & tropical regions )\t reg>d to ! dep?4 ,! great body ( ! ocean wat] ly+ bel[ a dep? ( "s few hundr$ fa?oms is ne>ly t5antless1 ?\gh life reappe>s sp>+ly at ! bottom1 ev5 :]e ! dep? is great4 ,= fur!r discussion ( ?is topic1 see ,*apt] ,,xi4 ,,processes ,,9 ,,op]ation ,,9 ,,! ,,sea4 ,)9 ! area ( ! sea1 z on ! area ( ! l&1 ?ree sets ( processes are at "w--dia/rophism1 vulcanism1 & gradation4 ,dia/rophism 7p4 #b7 affects ! sea-bottom z ! l&1 b ! results are notably diff]5t 9 c]ta9 respects4 ,s f> z ! li?osph]e is conc]n$1 ! sea-level may be said to be ! critical level4 ,at & above x1 _m processes are 9 op]ation :i* d n appe> bel[1 & bel[ x1 _m :i* d n take place above4 ,*anges ( level :i* d n involve ! subm]g5ce ( areas :i* 7 l&1 or ! em]g5ce ( areas :i* 7 "u wat]1 are relatively unimportant1 comp>$ ) ^? :i* effect su* *anges4 ,! rise ( ! bottom ( ! sea f a dep? ( #ejj fa?oms to a dep? ( #bjj fa?oms w\ld n lead to important consequ5ces1 s f> z ! area itself is conc]n$1 :ile an equal rise ( ! bottom b5ea? #bjj fa?oms ( wat]1 or an equal subsid5ce ( l& #ejj feet high1 w\ld be att5d$ by m /rik+ consequ5ces4 ,x foll[s t ! *anges effect$ by dia/rophism are mu* m obvi\s along coa/s ?an 9 ! deep seas4 ,em]g5ce or subm]g5ce %ifts ! zones ( aggradation & degradation1 %ifts ! zone ( contact ( ocean & l&1 & *anges ! region conc]n$ f "o appropriate = sea life to "o appropriate = t]re/rial =ms1 or vice v]sa4 ,ov] ! cont95tal %elves ! wat] is %all[ & ! bottom relatively smoo?4 ,if a coa/al region be elevat$ ev5ly1 or if ! sea-level be drawn d[n1 ! new %ore-l9e on ! smoo? surface ( ! =m] subm]g$ %elf w be relatively regul>1 ev5 ?\gh ! coa/ 0 notably irregul> be=e ! *ange4 ,?us 9 ,fig4 #big ! coa/-l9e is notably irregul>4 ,a sea-)drawal or a l&-uplift ( #abj feet w\ld *ange ! coa/-l9e to ! position ( ! #bj-;fa?om l9e1 :5 x w\ld be notably less irregul> ?an n[4 ,if x 7 %ift$ to ! #ajj-;fa?om l9e1 few irregul>ities w\ld rema94 ,9 s f> z new coa/-l9es =m$ by ! l[]+ ( ! sea 7or rise ( ! cru/7 dep>t f /raightness1 x is usually by broad1 smoo? curves4 ,local uplifts ( coa/al l&s1 & especially uplifts along axes normal to ! tr5d ( ! coa/1 w\ld give rise to projections ( l&1 & s to coa/al irregul>ities2 b su* uplifts are r>ely s localiz$ z to give orig9 to m9or projections4 ,x foll[s t ris+ coa/s1 & ^? :i* h rec5tly ris51 or m likely1 coa/s along :i* ! sea-level is s9k+ or has rec5tly sunk1 are likely to be regul> s f> z details ( outl9e are conc]n$4 ,subsid5ce ( a coa/-l9e 7or rise ( ! sea-level7 t5ds to ! opposite results1 = 9 ?is case ! sea advances on a surface :i* has m or less relief1 & ! wat] takes possession ( e depression br\ght to its level4 ,! l[] p>ts ( ! valleys are conv]t$ into bays1 ! l5g? & wid? ( :i* dep5d on ! slope & wid? ( ! valleys dr[n$4 ,! num]\s bays at ! deb\*ures ( ! /reams along ! ,atlantic coa/ ( ! ,unit$ ,/ates1 f ,long ,isl& ,s\nd to ,c>ol9a1 su* z ! ,delaw>e1 ,*esapeake1 7,fig4 #big7 & num]\s small] bays1 are ! results ( rec5t s9k+1 :i* has all[$ ! sea to invade ! l[] ends ( riv] valleys4 ,! ragg$ coa/ ( ,ma9e is ano!r example1 ?\gh glaciation z well z subsid5ce has be5 op]ative "h4 ,f ! pres5t configuration ( coa/-l9es1 x has be5 inf]r$ t ! pres5t is1 on ! :ole1 an era ( cont95tal depression4#ade ,riv] valleys1 ! l[] ends ( :i* are embay$1 are sometimes f\nd to be cont9u\s ) subm]g$ valleys beyond ! coa/-l9e 7,fig4 #bih74 ,subm]g$ riv] valleys %[ t ! surface 9 :i* !y lie 0 once l&4 ,illu/ration3 ,fig4 #big4--,sket* ( ! ea/]n coa/ ( ! ,unit$ ,/ates f ,cape ,may to ,cape ,h5ry1 %[+ coa/al irregul>ities4 ,! figures repres5t ! dep?s ( wat] 9 fa?oms4 7,f *>ts ( ,c4 & ,g4 ,surv47 ,illu/ration3 ,fig4 #bih4--,sket* ( ,c>mel ,bay1 ,cal4 ,! cont\rs bel[ sea-level %[ a deep subm]g$ *annel4 7,f *>ts ( ,c4 & ,g4 ,surv47 ,bays may be develop$ by local subsid5ce z well z by ! subm]g+ ( valleys1 ?\gh decisive examples are n readily cit$4 ,bays may also be produc$ by uplift ( ! surface on ei!r side ( an area :i* does n *ange its level4 ,= example1 uplift on ei!r side ( ! ,gulf ( ,cali=nia has probably be5 "o elem5t1 ?\gh probably n ! only "o1 9 ! developm5t ( ?is ind5tation4 ,! g5]al outl9e ( a great bay produc$ by coa/al w>p+ might be regul>1 ?\gh x w\ld be likely to be m>k$ by small irregul>ities :]e ! /reams ent]4 ,x is n to be und]/ood t all1 or ev5 mo/1 bays are due to local dia/rophism4 ,dia/rophism1 !n1 z x affects ! ocean-bottoms & ! ocean-bord]s1 may make ! wat] ( any ocean %all[] or deep]2 x may cause ! em]g5ce or subm]g5ce ( l&2 x may make coa/-l9es regul> or irregul>2 x may %ift ! habitat ( life1 & ?r\gh ^! *anges may greatly influ5ce ! processes ( gradation1 :i* are especially active along ! contact ( sea & l&4 ,vulcanism affects ! sea-bottom mu* z x affects ! l&4 ,at ! volcanic c5t]s1 :]e ! great body ( extrud$ matt] accumulates1 m\nds & m\nta9s are built up4 ,mo/ ( ! m\nta9 peaks ( ! sea-bottom1 :e!r _! cre/s are isl&s1 or :e!r !y are :olly subm]g$1 h _h a volcanic orig94 ,! rock mat]ial eject$ f subm>9e v5ts is probably less widely di/ribut$ ?an t f v5ts on l&1 & s f> =?1 ! volcanic cones 9 ! oceans are /eep] ?an ^? on l&4 ,:]e volcanic cones are built up ne> ! surface ( ! sea1 !y (t5 furni% a home = %all[-wat] life1 su* z polyps4 ,:]ev] built up s z to be )9 ! rea* ( waves1 gradational processes are /imulat$4 ,! processes ( vulcanism d n commonly influ5ce coa/s ( cont95ts directly1 = few volcanoes lie imm$iately on coa/s4 ,9 places1 h[ev]1 z at v>i\s po9ts 9 & ab\t ,italy1 ! configuration ( ! coa/ is influ5c$ by ! build+ ( volcanoes4 ,indirectly1 vulcanism influ5ces ! %ape ( coa/-l9es1 = ! resi/ance ( igne\s rock is (t5 diff]5t f t ( ! rock ) :i* x is associat$1 & "u ! influ5ces ( ! =ces ( gradation x may come to =m project+ po9ts or rentrants1 z ! case may be4 ,! numb] ( active volcanoes on isl&s is ab\t #bjj1 or ab\t two-?irds ( all n[ kn[n4 ,s9ce ! area ( ! sea is ab\t ?ree times t ( ! l&1 ! kn[n active volcanoes 9 ! sea are r less num]\s p] unit area ?an ^? on ! l&4 ,! numb] ( active v5ts b5ea? ! sea is altoge!r unkn[n4 ,a few subm>9e eruptions h be5 obs]v$1 & ^? obs]v$ are probably b a small p]c5tage ( ^? :i* h tak5 place 9 hi/oric "t4 ,slight eruptions 9 deep wat] might n manife/ !mselves at ! surface 9 an unequivocal way1 ev5 7 obs]v]s /ation$ ne> !m4 ,volcanic cones :i* fail to rea* ! surface are kn[n1 & ! =ms ( _m sea-bottom m\nta9 peaks are su* z to make x probable t !y are volcanic4 ,^! ph5om5a1 z well z ! num]\s volcanic isl&s1 give "s indication ( ! importance ( subm>9e eruptions 9 pa/ "t4 ,ocean volcanoes1 & especially subm>9e volcanoes1 affect bo? ! temp]ature & ! composition ( ! sea-wat]4 ,bo? ! increase ( temp]ature & ! solution ( volcanic gases increase ! capacity ( ! wat] = m9]al matt]1 & bo? ! *ange 9 temp]ature & composition affect ! life ( ! adjac5t wat]s4 ,! de/ruction ( life dur+ eruptions occasions ! g5]ation ( ! products ( organic decomposition1 & ^! /imulate fur!r *emical *anges4 ,! diffusion ( affect$ wat]s occasions *emical *anges :]ev] !y g4 ,! effects ( oceanic volcanoes on ! sea-wat] are1 !re=e1 appreciable1 :5 long p]iods ( "t are consid]$4 ,! deposition ( ! f9] p>ts ( volcanic dis*>ges w be consid]$ 9 connection ) ! deposits ( ! deep sea4 ,gradation4--,! gradational processes ( ! l& & ! sea are 9 /rik+ contra/4 ,on ! l&1 degradation pr$om9ates1 & aggradation is subord9ate4 ,9 ! sea1 aggradation pr$om9ates1 & degradation is subord9ate4 ,on ! l&1 degradation is1 on ! :ole1 greate/ :]e ! l& is highe/1 :ile aggradation is ( consequ5ce only :]e ! l& is l[1 or :]e /eep slopes give place to g5tle ones4 ,9 ! sea1 degradation is virtually conf9$ to %all[ wat]1 or to :at might be call$ ! highl&s ( ! sea1 :ile aggradation is ne>ly univ]sal1 b mo/ consid]able 9 %all[ wat]1 or :]e %all[ wat] gives place to deep4 ,bo? ! degradational & aggradational "w ( ! sea are greate/ ne> its %ores4 ,oppos$ z ! gradational "w ( ! l& & sea are1 !y yet t5d to a common end--! level+ ( ! surface ( ! li?osph]e4 ,! gradational processes :i* affect ! sea-bottom may be divid$ into ?ree categories3 7#a7 ,^? effect$ by me*anical means1 7#b7 ^? effect$ by *emical means1 & 7#c7 ^? effect$ by organic ag5cies4 ,! me*anical "w ( gradation 9 ! sea is effect$ *iefly by ! movem5ts ( ! wat]1 &1 v subord9ately1 by ! movem5ts ( ! ice :i* ! wat] c>ries4 ,! results ( ^! movem5ts may be degradational :]ev] ! wat] is suffici5tly %all[ = ! motion to affect ! bottom4 ,else:]e x is aggradational4 ,! direct gradational "w effect$ by *emical means is likewise p>tly degradational & p>tly aggradational4 ,if at any "t or place ! wat] becomes sup]saturat$ ) any m9]al sub/ance1 precipitation takes place1 & ! precipitate accumulates z s$im5t on ! bottom4 ,?is sometimes happ5s 9 lagoons & o!r small inclosures1 & p]haps 9 op5 wat]4 ,on ! o!r h&1 :]ev] solution is effect$1 degradation is ! result4 ,solution is mo/ important :]e ! bottom consi/s ( relatively soluble rock1 su* z lime c>bonate4 ,organic ag5cies are1 on ! :ole1 aggradational4 ,accumulations ( coral1 coral dbris1 %ells1 etc41 help to build up ! sea-bottom1 & mo/ rapidly 9 %all[ wat] :]e ! prop] =ms ( life are mo/ abundant4 ,"h also %\ld be m5tion$ ! accumulations ( c>bonace\s matt]1 especially 9 ! =m ( plant bodies4 ,9 ! aggradation effect$ directly by organic ag5cies1 ! sea is passive4 ,its only "p is to support ! life :i* gives rise to ! solid matt]1 & incid5tally to float a "p ( x 9 its curr5ts4 ,,movem5ts ,,( ,,! ,,sea-,,wat]4 ,! movem5ts ( ! sea-wat] fall into sev]al categories4 ,!re is 7#a7 a g5]al circulation ( sea-wat]1 det]m9$ *iefly by ?ree factors3 diff]5ces 9 d5sity 9 ! sea-wat]1 diff]5ces ( level1 & ! g5]al movem5ts ( ! atmosph]e2 7#b7 p]iodic movem5ts :i* are n prim>ily circulatory1 br\ght ab\t by ! attraction ( ! sun & moon2 & 7#c7 ap]iodic movem5ts1 due to occasional causes1 su* z e>?quakes1 volcanic explosions1 l&slides1 etc41 :i* det]m9e local & tempor>y movem5ts1 (t5 ( exceptional /r5g?4 ,diff]5ces 9 d5sity & _! results4--,diff]5ces 9 d5sity result f diff]5ces 9 temp]ature & sal9ity4 ,temp]ature alone consid]$1 wat] w\ld be d5se/ :]e x is colde/1 namely 9 ! pol> regions4 ,diff]5ces 9 sal9ity result f diff]5ces 9 evaporation & f inequalities 9 ! supply ( fre% wat]4 ,evaporation alone consid]$1 ! sea-wat] %\ld be d5se/ :]e evaporation is greate/2 b ! equatorial region1 :]e evaporation is greate/1 is also a region :]e precipitation is heavy1 & precipitation1 by fre%5+ ! wat]1 opposes ! effect ( great evaporation4 ,! greate/ diff]5ces 9 d5sity due to ! unequal supply ( fre% wat] are to be f\nd ne> ! bord]s ( cont95ts1 :]e ! precipitation on ! l& is dis*>g$ into ! sea4 ,9 ! pol> regions1 ! great supply ( fre% wat]1 especially dur+ ! season :5 ! ice is melt+1 opposes ! effect ( ! l[ temp]ature1 s f> z ! d5sity ( ! wat] is conc]n$4 ,! result ( ! op]ation ( ^! factors affect+ ! d5sity ( ! sea-wat] is to insure a g5]al circulation1 direct$ to ! end ( equaliz+ ! d5sities2 & s9ce ! di/urb+ factors are con/antly 9 op]ation1 equilibrium is nev] e/abli%$1 & ! movem5ts ( ! wat] are p]petual4 ,! pressure gradi5ts result+ f diff]5ces ( d5sity are s slight t ! result+ movem5ts are sc>cely m ?an a creep ( ! wat]s4 ,9 g5]al !y are f> too sl[ to be ( importance 9 gradational "w2 b ! e>?'s rotation deflects ! creep+ wat]s & t5ds to conc5trate ! equator-w>d movem5t into curr5ts on ! ea/ sides ( ! cont95ts1 & ! pole-w>d movem5t on ! we/ sides4 ,9 favorable situations ^! curr5ts may be compet5t to produce s5sible me*anical results4 ,ev5 :]e ?is is n ! case ! circulation helps to equalize ! temp]atures ( ! sea1 & s ( ! air above & ( ! l& ab\t4 ,indirectly1 !re=e1 ! circulation ( ! ocean-wat]s affects e geological process :i* is s5sitive to climate4 ,diff]5ces 9 level & _! results4--,:ile ! surface ( ! ocean is ! common datum plane to :i* elevations & depressions are ref]r$1 x is to be rememb]$ t ! sea has 8a v complicat$ undulat+ surface 9 consequ5ce ( ! attraction :i* ! het]og5e\s & elevat$ portions ( ! li?osph]e ex]cise on ! liquid hydrosph]e4 ,9 ! op9ion ( geodesi/s1 ! geoid may 9 "s places dep>t f ! figure ( ! sph]oid by #ajjj feet40#adf ,^! v>iations 9 level w\ld1 h[ev]1 n occasion circulation4 ,! diff]5ces 9 level :i* det]m9e circulation are mu* m trivial4 ,e /ream :i* p\rs fre% wat] into ! sea t5ds to raise ! level ( ! wat] :]e x ent]s4 ,! wat]s br\ght to ! ocean by ! ,amazon1 ! ,mississippi1 & o!r great riv]s w\ld appreciably *ange ! level ( ! sea at _! deb\*ures1 if ! excess did n promptly fl[ away4 ,! ready mobility ( ! wat]1 h[ev]1 prev5ts its accumulation1 & ! dis*>ge ( e /ream g5]ates widespread movem5t4 ,?is movem5t is /ronge/ at ! deb\*ure1 & weak5s ) increas+ di/ance f x1 ?\gh 9 ! case ( great /reams1 su* z ! ,amazon1 ! movem5t is traceable1 by means ( ! s$im5t :i* ! wat] c>ries1 hundr$s ( miles out to sea4 ,*anges ( level are also br\ght ab\t by ! w9ds1 :i* pile up wat] along ! %ore aga9/ :i* !y bl[4 ,! level ( ! wat] is said to h ris5 #bd feet at ,calcutta on ,octob] #e1 #ahfd1 z ! result ( a sev]e /orm4 ,:ile ?is is exceptional1 a rise ( #b feet is n r>e4 ,?is pil+ up ( ! wat]s along %ore insures a comp5sat+ movem5t 7und]t[1 littoral curr5ts1 etc47 9 "s o!r direction4 ,unequal evaporation & precipitation likewise di/urb ! level ( ! sea & occasion movem5t4 ,9 ! op5 sea ! movem5ts g5]at$ by diff]5ces ( level1 l ^? g5]at$ by diff]5ces ( d5sity1 are *iefly sl[1 creep+ movem5ts1 b movem5ts :i* nev] cease4 ,9 bays & gulfs1 on ! o!r h&1 ! surface ( ! wat] may be s rais$1 ei!r z ! result ( w9d1 riv] dis*>ge1 or heavy precipitation1 z to give rise to /rong outw>d curr5ts4 ,!re is little d\bt at ! pres5t "t t ! ,gulf ,/ream owes its orig9 prim>ily to ! diff]5ce ( level betwe5 ! ,gulf ( ,mexico & ! ,atlantic4#adg ,movem5ts g5]at$ by w9ds4--,! circulation result+ f ! t5d5cy ( ! w9ds to *ange ! level ( ! sea-wat] has already be5 m5tion$1 b ! w9d also works 9 o!r ways4 ,:]e ! w9ds h a some:at con/ant direction & are at ! same "t /rong1 !y det]m9e a g5]al movem5t ( ! surface-wat]s 9 _! own direction1 ! surface-wat] be+ dragg$ along at a rate some:at less ?an t ( ! w9d itself4 ,! con/ant trades appe> to be ! *ief g5]ators ( ! equatorial ocean-curr5ts4 ,once g5]at$1 ^! curr5ts may be conc5trat$ & _! c\rses modifi$4 ,! curr5ts g5]at$ by trades are turn$ nor? & s\? :5 direct$ aga9/ a cont95t2 !y are modifi$ by ! configuration ( ! bottom if ! wat] be %all[1 & always & ev]y:]e1 except1 at ! equator1 !y are deflect$ by ! rotation ( ! e>?1 9 ! nor!rn hemisph]e to ! "r1 & 9 ! s\!rn to ! left4 ,! pole-w>d curr5ts g5]at$ 9 ! equatorial region by ! trades1 & direct$ by ! w9ds1 ! l&s1 ! configuration ( ! bottom1 & ! rotation ( ! e>?1 det]m9e comp5sat+ curr5ts f high latitudes to l[1 & ! same influ5ces :i* control ! c\rse ( ! =m] direct ! latt] z well4 ,s9ce ! atmosph]ic movem5ts are s f> con/ant t !re is a prevail+ direction ( w9ds 9 all latitudes1 ! w9ds1 z well z diff]5ces ( d5sity & diff]5ces ( level1 insure a g5]al & cont9ual circulation ( sea-wat]4 ,! geological effects ( ?is circulation are direct & indirect2 direct1 by gradation ( ! bottom ov] :i* !y fl[1 & indirect1 by ! modifications ( climate !y produce4 ,s9ce rotation deflects ! pole-w>d curr5ts to ! ea/ sides ( ! oceans 7we/ sides ( ! cont95ts7 & ! equator-w>d movem5ts to ! we/ sides ( ! oceans 7ea/ sides ( ! cont95ts71 ! ea/ %ores ( ! oceans are w>m] ?an ! we/ 9 correspond+ latitudes1 & ! we/ sides ( ! cont95ts are bo? w>m] & moi/]#adh ?an ! ea/ sides4 ,! mo/ obvi\s di/urbance ( sea-wat] result+ f ! w9ds is ! g5]ation ( waves4 ,waves are n prim>ily p>ts ( ! g5]al oceanic circulation4 ,s9ce !y are g5]at$ 9 o!r ways ?an by w9ds1 & s9ce ! gradational effects ( waves are indep5d5t ( _! orig91 ! effects ( w9d-waves w n be consid]$ sep>ately4 ,movem5ts g5]at$ by attraction4--,"o ( ! movem5ts ( ! sea-wat] :i* is n prim>ily circulatory results f ! attraction ( ! moon & sun4 ,! tide is really ! result ( ! inequalities ( ! attraction ( ^! bodies on diff]5t p>ts ( ! e>?4 ,! lun> tide is m important ?an ! sol>1 n because ! attraction ( ! moon is great]1 = x is n1 b because its diff]5tial attraction1 ! result ( its less] di/ance1 is great]4 ,! di/ance ( ! moon f ! e>? is ab\t #bdj1jjj miles4 ,if ?is be tak5 z ! di/ance f ! c5t] ( ! moon to ! c5t] ( ! e>?1 #bcf1jjj & #bdd1jjj miles respectively are ! di/ances f ! c5t] ( ! moon to ! ne>e/ & mo/ di/ant po9ts on ! e>?4 ,! di/ance ( ! sun f ! e>? is ab\t #ic1jjj1jjj miles4 ,if ?is be tak5 z ! di/ance betwe5 ! c5t]s ( ^! bodies1 !n ! di/ances f ! c5t] ( ! sun to ! ne>e/ & mo/ di/ant po9ts on ! e>?'s surface are #ib1iif1jjj & #ic1jjd1jjj miles respectively4 ,! ratio ( #djjj to #bcf1jjj or to #bdd1jjj is mu* great] ?an ! ratio ( #djjj to #ib1iif1jjj or to #ic1jjd1jjj4 ,h5ce ! tide-produc+ =ce ( ! moon is great] ?an t ( ! sun4 ,! tides %[ !mselves along %ores 9 ! =m ( waves :i*1 9 %all[ wat]1 become translatory4 ,!y diff] f ! w9d-waves 9 _! p]iodicity1 & locally 9 _! great] height4 ,! effects ( ! tidal waves on ! %ores ( ! sea1 & on ! bottom 9 %all[ wat]1 are ! same z ! effect ( w9d-waves ( equal /r5g?1 & ne$ n be sep>ately consid]$ 9 connection ) ! gradation ( ! sea-bottom4 ,9 pass+ ?r\gh n>r[ /raits or n>r[ passes ( any sort1 ! tidal movem5t becomes a curr5t :i*1 "u favorable conditions1 abrades or 8sc\rs0 ! bottom effectively4 ,! tidal curr5ts 9 ! n>r[ passes ab\t ,new ,york h>bor may s]ve z an illu/ration4 ,ap]iodic movem5ts4--,9 addition to ! w9d-waves :i* are ess5tially con/ant & univ]sal1 & to ! tidal waves1 :i* are p]iodic1 !re are accid5tal waves :i* are locally & tempor>ily ( importance4 ,su* are e>?quake-waves1 :i* are sometimes extremely de/ructive4 ,?us an e>?quake-wave on ! coa/ ( ,p]u 9 #agdf swept a frigate sev]al miles inl& & delug$ ,lima1 sev5 miles f ! %ore4 ,! havoc ( mo/ e>?quakes affect+ coa/s1 su* z t ( ,lisbon 9 #agee1 is greatly aggravat$ by accompany+ sea-waves4 ,e>?quake-waves diff] f ord9>y waves 9 be+ translatory1 & s 9 be+ m effective on ! bottom 9 deep wat]4 ,_! greate/ =ce1 h[ev]1 is felt 9 %all[ wat] & on %ores4 ,volcanic eruptions likewise give rise to exceptional ap]iodic waves4 ,! same is true ( l&slides :]e !y affect ! coa/ or any "p ( ! sea-bottom4 ,! fall ( glaci] ends & ! capsiz+ ( iceb]gs likewise g5]ate /rong waves4 ,to ! category ( exceptional waves also belong ^? g5]at$ by ! w9ds ( exceptional /orms1 su* z t :i* deva/at$ ,galve/on 9 #aijj4adi ,summ>y4--,f ! po9t ( view ( _! direct geological results 9 %all[ wat]1 all movem5ts ( ! sea-wat] may be gr\p$ into two ma9 classes--7#a7 waves1 ) ! und]t[ & ! littoral curr5ts !y g5]ate1 & 7#b7 ocean-curr5ts4#aej ,,waves4 ,wave-motion4#aea--,! mo/ common waves1 & f ! pres5t po9t ( view ! mo/ important1 are ^? g5]at$ by w9ds4 ,dur+ ! passage ( a wave1 ea* p>ticle affect$ by x rises & falls1 & moves =w>d & backw>d describ+ an orbit 9 a v]tical plane4 ,if ! pass+ wave is a swell1 ! orbit ( ! p>ticle is clos$ & is ei!r a circle or an ellipse2 b 9 ! case ( a w9d-wave ! orbit is n clos$4 ,9 su* a wave two ?+s move =w>d1 ! undulation & ! wat]4 ,! velocity ( ! undulation is relatively rapid2 t ( ! wat]1 sl[ & rhy?mic4 ,on ! cre/ ( ! w9d-wave ea* p>ticle ( wat] moves =w>d1 & 9 ! tr\gh x moves less rapidly backw>d1 & ! excess ( ! =w>d movem5t ov] ! backw>d gives x a slight residual advance4 ,?is residual advance is ! initiatory elem5t ( curr5t4 ,by virtue ( x1 ! upp] lay] ( wat] is c>ri$ =w>d ) ref]5ce to ! lay] bel[1 9 ! direction t[>d :i* ! w9d bl[s4 ,! waves ( any consid]able or long-cont9u$ w9d1 !re=e1 g5]ate a curr5t t5d+ 9 ! same direction z ! w9d4 ,! agitation ( :i* waves are ! sup]ficial manife/ation is n re/rict$ to ! surface1 b is propagat$ indef9itely d[nw>d4 ,ne> ! surface ! am\nt ( motion dim9i%es rapidly ) increas+ dep? 7,fig4 #bii71 b ! rate ( dim9ution itself dim9i%es1 & !re seems no !oretic reason = assign+ any def9ite limit to ! d[nw>d propagation ( ! oscillation4 ,illu/ration3 ,fig4 #bii4--;,figure illu/rat+ ! decrease 9 ! am\nt ( wave-movem5t ) increase ( dep?4 7,f5neman47 ,at ! surface1 ! radius ( ! circul> orbit :i* a p>ticle ( wat] 9 a wave t5ds to describe is half ! height ( ! wave4 ,at a dep? equal to "o wave-l5g?1 ! radius ( ! circle describ$ by a p>ticle is z great z at ! surface1 & at a dep? equal to two wave-l5g?s1 4 ,if ! height ( a wave be #dc feet1 ! radius ( ! circle describ$ by a surface p>ticle is #ba feet4 ,if ! l5g? ( ! wave be #cjj feet1 ! radius ( a p>ticle at a dep? ( #cjj feet is only ab\t ( an in*1 & at #fjj feet ( an in*4#aeb ,^! figures make x cle> t effective agitation ( ! wat] does n ext5d to great dep?s4 ,s long z ! velocity ( ! w9d rema9s con/ant1 ! velocity ( ! curr5t :i* ! w9d-waves g5]ate is less ?an t ( ! w9d1 & !re is always a diff]5tial movem5t ( ! wat]1 ea* lay] mov+ fa/] ?an ! "o b5ea?4 ,! friction is ?us di/ribut$ ?r\gh ! :ole v]tical column ( ! wat] 9 movem5t1 & is ev5 borne 9 "p by ! sea-bottom if ! movem5t ext5ds s f> d[n4 ,! great] ! dep?1 ! small] ! %>e ( ! friction ea* lay] ( wat] is call$ ^u to be>1 & ! great] ! velocity ( ! curr5t g5]at$ by a giv5 w9d4 ,b :ile ! wave-motion ext5ds indef9itely d[nw>d1 ! l[] limit ( agitation effective 9 erosion is soon rea*$4 ,eng9e]+ op]ations h %[n t subm>9e /ructures are little di/urb$ at dep?s ( five met]s 9 ! ,m$it]ranean & eight met]s 9 ! ,atlantic4#aec ,on ! o!r h&1 dbris z co>se z gravel1 :i* is transport$ by roll+ on ! bottom1 is n infrequ5tly c>ri$ out to dep?s ( #ej feet1 & sometimes ev5 to #aej feet4 ,f9e s$im5t1 l silt1 is di/urb$ at /ill great] dep?s1 = ripple-m>ks1 :i* indicate agitation ( ! wat]1 are said to h be5 f\nd at dep?s ( #ajj fa?oms4#aed ,:5 a wave approa*es a %elv+ %ore1 its habit is *ang$4 ,! velocity ( ! undulation is dim9i%$1 :ile ! velocity ( ! advanc+ p>ticle ( wat] 9 ! cre/ is increas$2 ! wave-l5g?1 measur$ f tr\gh to tr\gh1 is dim9i%$1 & ! wave-height is increas$2 ! cre/ becomes acute1 ) ! front /eep] ?an ! back1 & ^! *anges culm9ate 9 ! break+ ( ! cre/1 :5 ! undulation prop] ceases4 ,waves ( a giv5 height break 9 ab\t ! same dep? ( wat]1 & ! l9e along :i* incom+ waves break is ! l9e ( break]s4 ,! l9e ( break]s is 9 deep] wat] & f>!r f %ore :5 ! waves are /rong ?an :5 !y are weak4 ,waves are report$ to h brok5 9 #ajj fa?oms ( wat]1#aee b ?is mu/ be reg>d$ z v exceptional4 ,! return ( ! wat] ?r[n =w>d 9 ! cre/s ( waves is accompli%$ by a curr5t along ! bottom call$ ! und]t[4 ,! und]t[ is s5sibly normal to ! coa/ :5 un9flu5c$ by oblique waves1 & is effici5t 9 remov+ ! products ( erosion4 ,s9ce ! incom+ wave affects wat] :i* is at ! same "t "u ! influ5ce ( ! und]t[1 x gives to t curr5t a pulsat+ "*1 = ! wave-motion sometimes supports & sometimes opposes ! und]t[1 & ?us end[s x ) a high] transport+ p[] ?an belongs to its mean velocity4 ,ne> ! break]-l9e1 ! oscillations communicat$ by ! wave may mom5t>ily ov]come & ev5 rev]se ! movem5t ( ! und]t[4 ,inside ! break]-l9e1 irregul> oscillation only is communicat$4 ,! brok5 wave-cre/1 da%+ =w>d1 ov]comes ! und]t[ & ?r[s x back1 & ! wat] returns z a simple curr5t desc5d+ a slope4 ,! p[] ( ! und]t[ dim9i%es rapidly f ! break]-l9e outw>d z ! dep? ( ! wat] increases4 ,illu/ration3 ,fig4 #cjj4--;,diagram %[+ relative directions ( wave1 und]t[1 & %ore-curr5t4 ,:5 waves advance on ! %ore obliquely1 a %ore-curr5t is develop$ z illu/rat$ by ,fig4 #cjj1 :]e ab repres5ts ! direction ( ! incom+ wave1 bc ! direction ( ! littoral curr5t1 & bd ! direction ( ! und]t[4 ,:]e !y /rike ! bord]s ( l&1 ! w9d-waves1 !re=e1 g5]ate two o!r movem5ts1 ! und]t[ & ! littoral curr5t4 ,any p>ticle ( wat] ne> %ore may be affect$ by any two or by all ?ree ( ^! movem5ts at ! same mom5t4 ,! effect ( littoral curr5t & und]t[ is to give a p>ticle ( wat] on :i* bo? are work+ a direction betwe5 ! two1 z be4 ,! effect ( o!r comb9ations c be readily inf]r$4 ,^! v>i\s comb9ations are ( consequ5ce 9 ! transportation ( dbris4 ,,"w ,,( ,,! ,,waves4 ,erosion4 ,! g5]al effects ( ! waves & ! o!r movem5ts to :i* !y give rise along %ores are 7#a7 ! we> ( ! %ores2 7#b7 ! transportation = great] or less di/ances ( ! products ( we>2 & 7#c7 ! deposition ( ! transport$ mat]ials4 ,by waves & und]t[4--,9 ! da% ( ! waves aga9/ ! %ore1 ! *ief we> is effect$ by ! impact ( ! wat] & ( ! dbris :i* ! wat] c>ries4 ,less] results are accompli%$ 9 o!r ways4 ,:5 ! l& at ! m>g9 ( ! wat] consi/s ( unconsolidat$ mat]ial1 or ( fragm5tal mat]ial b slightly cem5t$1 ! impact ( ! wat] is suffici5t to displace or erode x4 ,if weak rock be associat$ ) resi/ant rock )9 ! zone ( wave-"w1 ! removal ( ! =m] may lead to ! disruption & fall ( ! latt]1 especially :5 weak rock is wa%$ out f b5ea? ! /rong4 ,! impact ( ! wat] is compet5t also to break up & remove rock :i* 0 once resi/ant1 b :i* has be5 sup]ficially weak5$ by *anges ( temp]ature4 ,rock affect$ by num]\s op5 jo9ts is likewise attack$ ) success1 = by ! da% ( ! waves ! blocks betwe5 ! jo9ts may be loos5$ & lit]ally qu>ri$ out4 ,x may1 h[ev]1 be d\bt$ :e!r ! da% ( waves ( cle> wat]1 ev5 :5 _! =ce is _m tons to ! squ>e foot1 has any appreciable p[] to we> rock :i* is ?or\ghly solid4 ,illu/ration3 ,fig4 #cja4--;,angul> blocks ( rock :i* h fall5 f ! cliff above1 z a result ( und]cutt+ by ! waves4 ,gr& ,isl&1 ,lake ,*ampla94 ,! rock is ,black ,riv] lime/one4 ,al?\gh f ! %ore ( a lake in/ead ( ! sea1 ! pr9ciples illu/rat$ are ! same4 7,p]ry47 ,! impact ( ! waves is g5]ally re9=c$ & made effective by ! impact ( ! detritus !y c>ry4 ,! s&1 ! pebbles1 & su* /ones z ! waves c move are us$ z weapons ( attack1 be+ turn$ aga9/ "o ano!r & aga9/ ! %ore4 ,masses ( rock too l>ge = ! waves to move 7,fig4 #cja7 are worn by ! detritus driv5 back & =? ov] !m1 & 9 "t r$uc$ to movable dim5sions 7,fig4 #cjb74 ,!y !n become ! tools ( ! waves1 & 9 use1 are r$uc$ to small] & small] size4 ,?us b[ld]s are r$uc$ to cobbles1 cobbles to pebbles1 pebbles to s&1 & s& to silt4 ,! silt is readily held 9 susp5sion 9 agitat$ wat]1 & ?us is c>ri$ out beyond ! range ( break]s1 & settles 9 wat] s deep z n to be effectively agitat$ to its bottom4 ,?us "o g5]ation ( b[ld]s aft] ano!r is worn out1 & ! comm9ut$ products are c>ri$ out f ! imm$iate %ore & deposit$ 9 deep] wat]4 ,! effectiv5ess ( waves1 :e!r !y "w by impact ( wat] alone1 or by impact ( wat] & detritus1 is dep5d5t on _! /r5g? & on ! conc5tration ( _! bl[s4#aef ,! /r5g? ( waves is dep5d5t on ! /r5g? ( ! w9ds 7or o!r g5]at+ cause7 & ! dep? & expanse ( ! wat]1 & ! conc5tration ( _! bl[s is condition$ by ! slope aga9/ :i* !y break4 ,on expos$ ocean-coa/s ! fet* ( ! waves is always great4 ,! w9ds are v>iable4 ,= a giv5 coa/ !y h an av]age /r5g?1 b ! effectiv5ess ( wave-erosion is det]m9$ less by ! av]age /r5g? ( waves ?an by ! /r5g? ( ! /orm-waves4 ,?is is (t5 v great4 ,on ! ,atlantic & ,nor? ,sea coa/s ( ,brita91 w9t] break]s :i* ex]t a pressure ( ?ree tons p] squ>e foot are n infrequ5t4#aeg ,s great is ! =ce ( exceptional /orm-waves t blocks ( rock exce$+ #ajj tons 9 weight are kn[n to h be5 mov$ by !m4 ,gr\nd-swells1 8ev5 :5 no w9d is bl[+1 (t5 cov] ! cliffs ( nor? ,scotl& ) %eets ( wat] & foam up to heights ( #ajj or ev5 ne>ly #bjj feet4 ,dur+ nor!a/]ly gales ! w9d[s ( ! ,dunnet ,head ligh?\se1 at a height ( upw>ds ( #cjj feet above high-wat] m>k1 are said to be sometimes brok5 by /ones swept up ! cliffs by %eets ( sea-wat]40#aeh ,! av]age =ce ( waves on ! ,atlantic coa/ ( ,brita9 has be5 f\nd to be #faa lbs4 p] squ>e foot 9 summ]1 & #bjhf lbs4 9 w9t]4#aei ,:]e deep wat] ext5ds up to ! %ore1 ! =ce ( ! wave is almo/ :olly exp5d$ ne> ! wat] l9e2 :]e %all[ wat] bord]s ! l&1 ! =ce ( ! waves is exp5d$ ov] a great] area4 ,waves are1 !re=e1 mo/ effici5t on bold coa/s bord]$ by broad expanses ( deep wat]4 ,! less famili> phases ( wave-"w are accompli%$ by hydraulic pressure1 compress$ air1 ! use ( ice1 etc4 ,:5 ! wat] ( a wave is driv5 into an op5 jo9t or a cave1 ! hydraulic pressure is great1 & if ! /ructure be weak1 ! rock may be brok54 ,:5 wat] is driv5 ) =ce into a cave1 ! compression ( ! air may be great if ! wave be high en\gh to close ! entrance4 ,:5 ! wat] runs out ( a cave1 ! air )9 may be greatly r>efi$1 :ile t above ex]ts its normal pressure4 ,9 ei!r case ! ro( ( ! cave1 if x be weak1 may be brok54 ,at c]ta9 seasons ( ! ye>1 especially dur+ ! spr+1 waves make de/ructive use ( ! ice :i* is !n break+ up1 b x is only 9 high latitudes t sea-ice is ( consequ5ce 9 ?is way4 ,9 g5]al1 ! effect ( its pres5ce 9 keep+ d[n waves ov]balances its effect z an ag5t ( erosion4 ,illu/ration3 ,fig4 #cjb4--,%[+ blocks simil> to ^? ( ,fig4 #cjf1 r$uc$ & r\nd$ by wave-action4 ,%ore ( ,lake ,*ampla94 ,! rock is ,utica %ale4 7,p]ry47 ,! direct effect ( wave-erosion is re/rict$ to a zone :i* is n>r[ bo? horizontally & v]tically4 ,!re is no impact ( break]s at levels l[] ?an ! tr\ghs ( ! waves1 ?\gh erosion may ext5d d[n to ! limit ( effective agitation 7p4 #cda74 ,! effici5t impact ( waves is limit$ upw>d by ! level ( ! wave-cre/s1 al?\gh ! da% ( ! wat] produces feebl] bl[s at high] levels4 ,! rise & fall ( ! wat] dur+ ! fl[ & ebb ( ! tides gives ! waves a great] v]tical range ?an w9d-waves alone w\ld h4 ,! v]tical zone ( direct wave-"w is !re=e limit$ above by ! level ( wave-cre/s1 & bel[ by ! dep? ( wave-tr\ghs 7ne>ly74 ,! indirect "w ( waves is limit$ only by ! height ( ! %ore1 = z ! zone ( excavation is c>ri$ l&w>d1 masses high] up ! slope are und]m9$ & fall4 ,! fall5 rock tempor>ily protects ! %ore aga9/ ! waves1 b are !mselves ev5tually brok5 up4 ,illu/ration3 ,fig4 #cjc4--;,diagram illu/rat+ high sea-cliffs4 ,x also %[s a subm]g$ t]race1 due p>tly to wave-cutt+ 7wave-cut t]race71 & p>tly to build+ 7wave-built t]race74 7,gilb]t47 ,illu/ration3 ,fig4 #cjd4--;,diagram %[+ a l[ sea-cliff4 7,gilb]t47 ,! pulsat+ curr5t ( ! und]t[ 7p4 #cda7 has bo? an erosive & a transport+ function4 ,x c>ries ! detritus ( ! %ore to & fro1 & dragg+ x ov] ! bottom1 cont9ues d[nw>d ! erosion initiat$ by ! break]s4 ,?is d[nw>d erosion is ! necess>y concomitant ( ! %orew>d progress ( wave-erosion2 =1 if ! l& 7 m]ely plan$ away to ! level ( ! wave-tr\ghs1 ! incom+ waves w\ld break :]e %oal wat] 0 fir/ rea*$1 & become ineffective at ! wat] m>g94 ,! rate ( erosion by ! und]t[ becomes less & less z ! surface x affects is l[]$4 ,littoral curr5ts d little erosive "w beyond t inflict$ on ! mat]ial :i* !y transport4 ,! g5]al result ( wave-erosion is ! advance ( ! sea on ! l&1 ! rate ( advance be+ det]m9$ *iefly by ! nature ( ! mat]ial attack$ & ! /r5g? ( ! waves4 ,num]\s z examples are ( ! retreat ( coa/-l9es be=e ! advance ( ! sea1 x is n to be und]/ood t ! advance ( ! sea on ! l& is univ]sal or un9t]rupt$4 ,num]\s in/ances may be cit$ ( ! encroa*m5t ( ! l& on ! sea4 ,at ,long ,bran* ! advance ( ! sea1 9 spite ( elaborate breakwat]s1 has be5 s rapid 9 rec5t ye>s z to m5ace important build+s1 :ile a few miles to ! nor? & s\?1 ! l& is advanc+ 9 ! face ( ! waves4 ,! l[ coa/ ( ! ,middle ,ne!rl&s has retreat$ two miles or m 9 hi/oric times1#afj b ! opposite t5d5cy is %[n at o!r po9ts 9 ! same region4 ,on ! coa/ ( ,engl& ! sites ( villages h disappe>$ by ! advance ( ! sea )9 hi/oric times1#afa b ! coa/ ( ! same isl& af=ds illu/rations ( l& advance4 ,on ! s\? side ( ,nantucket isl&1 ! sea-cliff has be5 kn[n to retreat be=e ! waves z mu* z six feet 9 a s+le ye>4#afb ,almo/ e consid]able /ret* ( coa/ af=ds illu/rations bo? ( ! advance ( ! sea on ! l& & ( l& on ! sea2 b 9 ! long run1 ! =m] mu/ exce$ ! latt]1 dia/rophic movem5ts aside4 ,illu/ration3 ,fig4 #cje4--,/eep cliff develop$ by waves4 ,all5 ,po9t1 ,gr& ,isl&1 ,lake ,*ampla94 7,p]ry47 ,illu/ration3 ,fig4 #cjf4--;,cliff 9 unconsolidat$ mat]ial 7b[ld] clay71 ) lake-bea* 9 =egr\nd4 ,s\? ,manit\ ,isl&1 ,lake ,mi*igan4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cjg4--,/eep cliff 9 unconsolidat$ mat]ial1 ! result ( rapid cutt+4 ,s\!a/ extremity ( ,grove ,po9t1 ,md4 ,topographic ,features ,develop$ by ,wave-erosion4 ,illu/ration3 ,fig4 #cjh4--,/&+ ,rock4 ,a wave-erosion monum5t4 ,we/ %ore ( ,r&om ,s\nd1 s\? ( ,cl>5ville1 ,n4 ,f4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,! sea-cliff4--,! action ( ! waves1 cutt+ z !y d along a def9ite horizontal zone1 has be5 comp>$ to ! action ( a horizontal saw4 ,z ! waves cut into ! %ore at & ne> ! wat]-level1 ! mat]ial above1 be+ unsupport$1 falls1 leav+ a /eep face above ! l9e ( cutt+4 ,?is /eep face is kn[n z ! sea-cliff 7,figs4 #cja to #cjf74 ,! same t]m is sometimes appli$ to ! cliffs ( lakes4 ,! pr9ciples involv$ 9 ! developm5t ( ! sea-cliff are applicable to any broad /ret* ( wat]4 ,! height ( ! cliff dep5ds on ! height ( ! l& on :i* ! sea is advanc+4 ,its slope may be /eep or g5tle 7comp>e ,figs4 #cjc to #cjf71 accord+ to ! nature ( ! mat]ial ( :i* x is compos$ & ! rapidity ( ! cutt+4 ,rapid cutt+ t5ds to produce /eep cliffs & sl[ cutt+ g5tle ones1 = 9 ! latt] case wea!r+ is m important relative to ! cutt+1 & at sea-level 7l[ altitudes7 wea!r+ g5]ally t5ds to r$uce ! angle ( slope4 ,9 g5]al1 ! m resi/ant ! mat]ial ! /eep] ! slope ( ! cliff4 ,incoh]5t mat]ials1 su* z s& & clay1 are n likely to =m /eep cliffs2 b if ! cutt+ be v rapid1 bold faces may be develop$ ev5 9 su* mat]ials 7,fig4 #cjg74 ,if b$s ( slight resi/ance at sea-level und]lie b$s ( great] resi/ance1 ! developm5t ( /eep cliffs is favor$4 ,! /ructure ( ! cliff-rock also has an influ5ce on ! slope4 ,! rock may be massive or b$d$4 ,if b$d$1 ! b$s may be horizontal1 or !y may dip at any angle1 9 any direction4 ,! rock1 :e!r /ratifi$ or n1 may be abundantly or sp>sely jo9t$4 ,all ^! /ructures influ5ce ! slope & configuration ( ! sea-cliff 7see ,figs4 #cje to #cjh74 ,illu/ration3 ,fig4 #cji4--8,old ,man ( ,hoy40 7,geikie47 ,*imney-rocks1 etc4--,by work+ 9 along ! jo9ts ( ! rock1 wid5+ !m & qu>ry+ out ! int]v5+ blocks1 pill>s ( rock 78*imney-rocks10 8pulpit-rocks07 or ev5 consid]able islets are sometimes isolat$ by ! waves4 ,?is is mo/ readily accompli%$ :]e ! jo9ts conv]ge back f ! %ore4 ,a well-kn[n example ( ?is sort is ! 8,old ,man ( ,hoy0 7,fig4 #cji7 on ! coa/ ( ! ,orkneys4 ,a pulpit-rock or o!r isl&1 or any jutt+ po9t ( rock may be pi]c$1 giv+ an ar* or bridge4 ,la ,ro*e ,p]ce1 a /eep-fac$ isle ne> ,gasp ,h>bor1 is an example4 ,sea-caves4--,waves sometimes excavate caves at ! bases ( cliffs4 ,?is is especially likely to occur :]e ! rock is mu* jo9t$ & :]e ! jo9ts are n cont9u$ to ! surface 9 a s+le plane4 ,! bottom & ro( ( a sea-cave usually h a pron\nc$ incl9ation l&w>d4 ,if ! cliff be l[1 ! cave may be ext5d$ l&w>d until its ro( is pi]c$4 ,?r\gh su* an op5+ 9 ! top ( ! cliff ! wat] ( ! incom+ waves may be =c$ 9 ! =m ( spray4 ,on ! ,new ,engl& coa/ su* holes are sometimes kn[n z 8sp\t+ horns40 ,simil> op5+s may be made1 z already po9t$ out1 by ! compression or r>efaction ( ! air 9 ! cave z ! wave ent]s or retreats4 ,if ! ro( ( ! cave be p>tially de/roy$1 ! portion :i* rema9s may =m an ar* or bridge4 ,su* a bridge occurs on ,santa ,cruz ,isl&1 ,cali=nia 7,fig4 #caj74 ,illu/ration3 ,fig4 #caj4--;,an ar* develop$ by waves4 ,santa ,cruz ,isl&1 ,cal4 7,law47 ,! cave1 ! 8sp\t+ horn10 ! 8bridge10 ! 8pulpit-rock10 & o!r isolat$ islets1 are all closely associat$ ) ! sea-cliff 9 orig94 ,! wave-cut t]race4--,! bottom ( ! sea-cliff is bord]$ by a subm]g$ plat=m ov] :i* ! wat] is %all[4 ,?is plat=m1 or at any rate its l&w>d portion1 repres5ts ! area ov] :i* ! wat] has advanc$ z ! result ( wave-cutt+1 & is1 !re=e1 kn[n z ! wave-cut t]race4 ,f ! me?od ( cliff developm5t x w be se5 t ! wave-cut t]race is its necess>y accompanim5t4 ,su* a t]race has a g5tle slope to seaw>d1 = its out] & old] edge has be5 degrad$ long] & m4 ,its slope is influ5c$ by ! /r5g? ( ! waves1 be+ great] :]e !y are /rong]4 ,! out] edge ( ! wave-cut t]race is (t5 m>k$ by an abrupt desc5t4 ,fig4 #cjc repres5ts ! wave-cut t]race 9 its relation to ! sea-cliff above4 ,illu/ration3 ,fig4 #caa4--;,an elevat$ cliff above ,great ,salt ,lake4 ,9 ?is case ! wat]-level has be5 l[]$4 7,gilb]t1 ,u4 ,s4 ,geol4 ,surv47 ,s long z wave-cut t]races are subm]g$1 !y d n appe> on topographic maps ( ! l&1 ?\gh !y appe> on ! *>ts ( ! coa/s2 b if a coa/al tract ) wave-cut t]races be elevat$1 or if ! sea-level be drawn d[n1 ! t]races become l&4 ,elevat$ sea-cliffs & wave-cut t]races are among ! be/ evid5ces ( *ange ( relative level betwe5 wat] & l& 7,fig4 #caa74 ,wave-erosion & horizontal configuration4--,! /ructure ( ! rock along %ore has z mu* to d ) ! horizontal configuration ( ! wave-%ap$ coa/1 z ) its relief4 ,9 g5]al1 waves develop rentrants 9 ! less resi/ant portions ( ! %ore1 leav+ ! m resi/ant p>ts z headl&s 7,san ,p$ro ,po9t & ,devil's ,slide1 ,pl4 ,,xx1 ,coa/ ( ,cali=nia74 ,x is to be not$ t ! resi/ance ( rock to wave-erosion is n det]m9$ by its h>dness alone4 ,e division plane1 :e!r due to b$d+1 to jo9t+1 or to irregul> fracture1 is a s\rce ( weakness to ! rock1 & rock ( great h>dness may be s brok5 z to (f] relatively little resi/ance4 ,inequalities ( resi/ance1 :atev] _! cause1 give orig9 to inequalities ( coa/al configuration :]e wave-erosion is 9 progress4 ,giv5 a coa/ ( m>k$ regul>ity & equal exposure1 b compos$ ( unequally resi/ant mat]ial1 ! waves w make x irregul> by cutt+ mo/ :]e ! mat]ial is lea/ resi/ant4 ,a regul> coa/ ( uni=m mat]ial1 b unequal exposure1 w be made irregul> by ! great] cutt+ at ! po9ts ( great] exposure4 ,a coa/ ( m>k$ irregul>ity & homog5e\s mat]ial w be made m regul> by ! cutt+ (f ( ! project+ po9ts1 because !y are mo/ expos$4 ,) a giv5 set ( conditions1 waves t5d to develop a c]ta9 sort ( %ore-l9e :i*1 s f> z its horizontal =m is conc]n$1 is relatively /able4 ,su* a %ore-l9e may be said to be mature#afc s f> z wave-erosion is conc]n$4 ,s9ce coa/al l&s are1 9 g5]al1 bo? het]og5e\s & unequally expos$1 a mature coa/-l9e is some:at irregul>4 ,its maturity is atta9$ :5 ! less] exposure 9 ! rentrants develop$ 9 ! less resi/ant p>ts1 balances ! sup]ior exposure ( ! projections ( ! m resi/ant portions4 ,s9ce ! conditions ( erosion along coa/s are con/antly1 ev5 if sl[ly1 *ang+1 maturity is con/antly be+ approa*$1 b r>ely rea*$4 ,o!r =ces & processes1 su* z ^? ( aggradation1 vulcanism1 & dia/rophism1 are 9 op]ation along coa/s1 & _! results are sometimes antagoni/ic to ^? ( ! waves4 ,! horizontal configuration ( coa/s is1 !re=e1 ! result ( _m cop]at+ =ces1 ( :i* waves are b "o4 ,x is1 nev]!less1 important to note ! goal to :i* ! waves are work+1 ev5 ?\gh !y are cont9ually defeat$ 9 _! attempt to rea* x4 ,_! imm$iate goal is an equilibrium ( erosion-rate & maturity ( configuration2 _! f9al goal is ! de/ruction ( ! l& & ! deposition ( its sub/ance 9 ! sea1 t is1 9 a position ne>] ! c5t] ( gravity ( ! e>?4 ,transportation by ,waves4 ,! mat]ial erod$ f ! %ore by ! waves 9 ! %ap+ ( ! cliff & t]race is c>ri$ away by ! jo9t action ( ! waves1 und]t[1 & %ore-curr5ts4 ,! 9-com+ wave beg9s to %ift mat]ial :]e x beg9s to drag bottom1 t is1 a little outside ! l9e ( break]s4 ,f ! l9e :]e transportation beg9s1 to ! l9e ( break]s1 bottom detritus is %ift$ %orew>d by ! waves1 :ile ! und]t[ t5ds to c>ry x back aga94 ,betwe5 ! break]s & ! %ore !re is also a t5d5cy = ! on-%ore movem5t to c>ry dbris to ! wat]'s edge1 & = ! ebb+ wave to c>ry x back aga94 ,! result ( ^! oppos$ t5d5cies is to keep s$im5t 9 transit betwe5 ! %ore & ! l9e ( break]s4 ,if ! 9-com+ waves h a direction normal to ! %ore1 ! advance & recoil ( ! wat] move p>ticles t[>d & f ! %ore1 b effect no transf] along ! %ore2 b ! results :i* waves normal to ! %ore w\ld a*ieve are always modifi$ by o!r waves & by littoral curr5ts4 ,if ! 9-com+ wave is oblique to ! %ore1 x %ifts mat]ial 9 its own direction4 ,! transf] by und]t[1 tak5 alone1 w\ld be s5sibly normal to ! %ore1 b ! effect ( ! oblique waves is to slightly modify ?is direction4 ,!re is ?us a sl[ transportation along %ore1 ev5 9 ! abs5ce ( /eady curr5ts4 ,a great am\nt ( transportation w\ld be effect$ 9 ?is way1 ?\gh x w\ld be c>ri$ on at a sl[ rate4 ,oblique waves also t5d to develop a def9ite %ore-curr5t 7p4 #cdb7 :i* affects bo? ! am\nt & direction ( ! transportation4 ,any p>ticle 9 susp5sion1 or 9 motion on ! bottom z ! result ( ! wave or und]t[1 is %ift$ along %ore by ! littoral curr5t1 :i* affects ! same wat] 7,fig4 #cjj74 ,by ! cop]ation ( wave- & %ore-curr5t1 m & heavi] mat]ial c be mov$ ?an by ei!r alone1 & ! direction ( movem5t is m ne>ly p>allel to ! %ore ?an t ( ! wave4 ,simil>ly1 by ! cop]ation ( und]t[ & %ore-curr5t1 m & heavi] mat]ial c be mov$ ?an by ei!r alone4 ,! direction ( movem5t is readily inf]r$ f ,fig4 #cjj4 ,! direction 9 :i* dbris is %ift$ by wave- & %ore-curr5t is modifi$ by ! und]t[1 & ! direction :i* w\ld result f und]t[ & curr5t is modifi$ by ! wave4 ,x is (t5 ! waves ( /orms1 r ?an ^? ( ! prevail+ w9ds1 :i* det]m9e ! direction ( greate/ %ore transportation4 ,! waves1 ! und]t[1 & ! littoral curr5ts "w toge!r 9 assort+ ! detritus ( ! %ore4 ,! co>se/ p>ts may be beyond ! p[] ( all b ! /ronge/ waves4 ,!y accumulate :]e agitation is great4 ,less co>se p>ts are %ift$ f>!r f ! site ( greate/ agitation1 b no mat]ials :i* are class$ z co>se are c>ri$ beyond ! dep? ( s5sible movem5t4 ,! co>se mat]ial :i* cov]s ! bottom :]e ! agitation ( ! wat] at ! bottom is effective1 con/itutes %ore drift4 ,%ore drift is n all d]iv$ f ! %ore by ! cutt+ ( ! waves4 ,a "p ( x is br\ght to ! sea by /reams & m+l$ ) t erod$ f ! cliffs4 ,! mat]ial :i* is f9e en\gh to be held 9 susp5sion is measurably indep5d5t ( dep?4 ,?is is %[n dur+ /orms :5 ! wat] becomes turbid f> beyond ! l9e ( break]s1 & cle>s only aft] ! waves h di$ away4 ,?is sort+ ( %ore drift1 effect$ :ile x is 9 transportation1 is (t5 v p]fect4 ,! conditions favor+ assortm5t are 7#a7 vigor\s wave-action1 7#b7 prolong$ transportation1 & 7#c7 a mod]ate volume ( s$im5t4#afd ,! effect ( ^! sev]al conditions w be readily und]/ood4 ,ext5sive transportation ( %ore drift ( a giv5 degree ( co>s5ess is favor$ by 7#a7 /rong waves & und]t[1 7#b7 cont9u\s curr5ts1 & 7#c7 %all[ wat]1 deep5+ b gradually (f %ore4 ,deposition by ,waves1 ,und]t[1 & ,%ore-curr5ts4#afe ,illu/ration3 ,fig4 #cab4--;,cross-section ( ! bea*4 7,gilb]t47 ,! bea*4--,! zone occupi$ by ! %ore drift 9 transit is ! bea*4 ,! l[] m>g9 is b5ea? ! wat]1 a little beyond ! l9e :]e ! great /orm-waves break4 ,its upp] m>g9 is at ! level rea*$ by /orm-waves1 & is usually a few feet above ! level ( /ill wat]4 ,to ! bea*1 mat]ial is br\ght f seaw>d by ! 9-com+ waves1 & f x detritus is c>ri$ out by ! und]t[4 ,! cross-section ( a bea* is %[n 9 ,fig4 #cab4 ,9 horizontal position ! bea* foll[s ! g5]al b\nd>y betwe5 wat] & l&1 ?\gh x does n con=m to its m9or irregul>ities 7,fig4 #cac74 ,! bea* or b>ri] ridge (t5 causes ! deflection ( ! l[] c\rses ( /reams desc5d+ to x 7,pl4 ,,xxi74 ,illu/ration3 ,fig4 #cac4--;,a lake-bea* 7b>ri]72 ,griff9's ,bay1 ,lake ,ont>io4 ,illu/ration3 ,,plate ,,xxi4 ,,new ,,j]sey ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xxii4 ,fig4 #a4 ,,portion ,,( ,,s\? ,,coa/ ,,( ,,m>?as ,,v9ey>d1 ,,massa*usetts4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,portion ,,( ,,! ,,cali=nia ,,coa/ ,,ne> ,,tamalpais4 ,u ,s4 ,geol4 ,surv4 ,illu/ration3 ,fig4 #cad4--,section ( a b>ri]4 7,gilb]t47 ,! b>ri]4--,:5 ! agitation ( ! wat] along %ore becomes insuffici5t to c>ry ! mat]ial1 x is dropp$4 ,9 its deposition x assumes v>i\s =ms4 ,:]e ! bottom ( ! lake or sea ne> %ore has a v g5tle incl9ation1 ! 9-com+ waves break "s di/ance f ! %ore-l9e1 & x is "h t ! mo/ viol5t agitation occurs :5 ! waves are /rong4 ,to ?is l9e ( break]s1 mat]ial is %ift$ f bo? directions3 f %ore by und]t[1 & f seaw>d by ! waves4 ,accumulat+ "h1 x builds up a l[ ridge4 ,?is is a b>ri] 7,fig4 #cad74 ,if x is built up above ! surface ( ! wat] by /orm-waves1 x may %ut 9 a lagoon beh9d x1 & ?is may ultimately be fill$ by s$im5t wa%$ d[n f ! l&4 ,at "o /age 9 ! fill+1 ! lagoon becomes a m>%4#aff ,9 ! "p :i* ! b>ri] plays 9 ! hi/ory ( a coa/1 x is id5tical ) ! bea*4 ,illu/ration3 ,fig4 #cae4--;,a recurv$ spit4 ,dut* ,po9t1 ,gr& ,trav]se ,bay1 ,lake ,mi*igan4 ,illu/ration3 ,fig4 #caf4--;,cross-section ( a b>4 7,gilb]t47 ,! spit1 ! b>1 & ! loop4--,! disposition ( %ore-deposits dep5ds l>gely on ! curr5ts at & ne> %ore4 ,if ! coa/-l9e is deeply ind5t$1 ! littoral curr5t usually fails to foll[ ! rentrants4 ,9 hold+ its c\rse across ! m\? ( a small bay1 a %ore-curr5t usually passes into deep] wat]4 ,"h its velocity is *eck$ because its motion is communicat$ to ! wat] b5ea? x1 & a l>g] am\nt ( wat] be+ involv$ 9 ! motion1 ! motion ( ea* "p is dim9i%$4 ,if s$im5t 0 be+ mov$ along its bottom be=e ! curr5t 0 *eck$1 "s "p ( x is dropp$ :5 & :]e ! curr5t is slack5$4 ,x foll[s t deposition commonly takes place b5ea? a littoral curr5t z x crosses ! m\? ( a bay4 ,! belt ( deposition is (t5 n>r[1 & ! result is ! con/ruction ( a ridge b5ea? ! wat] 9 ! direction ( ! curr5t4 ,! curr5t w\ld nev] build ! embankm5t up to ! wat]-level1 b :5 its surface approa*es ! level ( effective agitation1 ! waves may beg9 to "w on x1 z on a b>ri]1 & may build x up to1 & ev5 above1 ! surface ( ! wat]4 ,s long z ! end ( su* an embankm5t is free1 x is a spit 7,fig4 #cae & ,pl4 ,,xxi74 ,if ! spit be l5g!n$ until x crosses1 or ne>ly crosses1 ! bay1 %utt+ x (f f ! op5 wat]1 x becomes a b>4 ,b>s h %ut 9 lakes 7ponds7 on ! coa/ ( ,m>?a's ,v9ey>d1 ,mass4 7,fig4 #a1 ,pl4 ,,xxii71 & lakes & lagoons at num]\s po9ts bo? on ! ,atlantic & ! ,pacific coa/s 7,fig4 #b1 ,pl4 ,,xxii1 ,rodeo lagoon74 ,! same ph5om5a are to be se5 along _m lake %ores4 ,b>s sometimes tie isl&s to ! ma9l& 7,pl4 ,,xxiii1 ,fig4 #a1 ,nahant1 ,mass42 ,fig4 #b1 ne> ,bidde=d1 ,me474 ,! /ructure ( a b> z se5 9 cross-section is %[n 9 ,fig4 #caf4 ,! con/ruction ( a spit has be5 aptly comp>$ to ! con/ruction ( a railway embankm5t across a depression4 ,! mat]ial is fir/ c>ri$ out f ! bord]+ upl& 7%all[ wat]7 & dump$ :]e ! slope to ! depression 7deep wat]7 beg9s4 ,! embankm5t ?us begun is ext5d$ by ! c>ry+ out ( new mat]ial1 :i* is left at ! end ( ! dump already made4 ,if ! bay across :i* ! b> is built receives abundant dra9age f ! l&1 ! outfl[ f ! bay may be suffici5t to prev5t ! completion ( ! b> 7,fig4 #b1 ,pl4 ,,xxii71 = :5 ! gr[? ( ! spit has suffici5tly n>r[$ ! outlet ( ! bay1 ! s$im5t br\ght to ! end ( ! spit by ! littoral curr5t w be swept out beyond ! spit by ! curr5t sett+ out f ! bay4 ,! completion ( a b> may be int]f]$ ) by tidal curr5ts1 ev5 )\t l&-dra9age4 ,curr5ts g5]at$ by ! tides may sweep 9 or out ( ! bay ) increas$ =ce z ! entrance is n>r[$1 c>ry+ 9 or out ! s$im5t :i* ! littoral curr5t w\ld h left at ! end ( ! spit4 ,! sc\r ( ! tides (t5 insures deep entrances 7inlets7 to bays1 & ma9ta9s def9ite *annels or 8?or(>es0 9 ! lagoon m>%es beh9d b>ri]s & spits4 ,! s$im5t br\ght d[n f ! l&1 z well z t wa%$ 9 by tidal curr5ts & waves1 t5ds to fill up ! lagoon beh9d a b>ri]1 a spit1 or a b>1 conv]t+ x into l& 7,fig4 #cag74 ,illu/ration3 ,fig4 #cag4--,sket* ( a portion ( ! ,new ,j]sey coa/4 ,! dott$ belt next ! sea is ! b>ri]1 modifi$ by ! w9d4 ,! area m>k$ by ! diagonal l9es is ! ma9l&4 ,9 ! m>%y area betwe51 !re are num]\s *annels or 8?or(>es0 kept op5 by ! curr5ts4 ,! figures %[ ! dep?s ( wat] 9 feet4 ,scale ab\t in* #a mile4 ,s9ce spits & b>s are built only :]e !re is %ore-drift 9 transit1 !y are always built out f a bea* or b>ri]4 ,! di/al end ( ! b> may also jo9 a bea* or b>ri]4 ,trac$ back to its s\rce1 ! bea* f :i* a spit leads out is (t5 f\nd to t]m9ate 9 ! cliff f :i* ! mat]ial ( ! bea* & ! spit 7 d]iv$ 7,pl4 ,,xx & ,fig4 #b1 ,pl4 ,,xxii74 ,9 su* cases ! s$im5t ( ! bea* has be5 %ift$ b a %ort di/ance2 b 9 o!r cases x has travel$ f>4 ,illu/ration3 ,fig4 #cah4--,map ( %ore-t]races1 l>gely wave-built4 ,lake ,bonneville4 7,gilb]t47 ,illu/ration3 ,fig4 #cai4--;,a portion ( ! ,texas coa/ %[+ ! t5d5cy ( %ore-deposition to simplify ! coa/-l9e4 ,! deposits 7! n>r[ necks ( l& p>allel to ! coa/7 %ut 9 ! bays4 7,f *>t ( ,c4 & ,g4 ,surv47 ,illu/ration3 ,fig4 #cbj4--,map %[+ t 9 ! e>ly /ages ( ! simplification ( a %ore-l9e ! irregul>ities are increas$4 ,! numb]s indicate ! dep? ( wat] 9 fa?oms4 7,f *>t ( ,c4 & ,g4 ,surv47 ,! spit is usually ei!r /raight or 9 con=mity ) ! g5]al c\rse ( ! %ore-curr5t1 b s9ce ! littoral curr5t itself is subject to alt]ation z ! result ( %ift+ w9ds1 ! spit may dep>t f /raightness4 ,w9ds :i* simply rev]se ! direction ( ! littoral curr5t ret>d its con/ruction1 b may n o!rwise affect x2 b if a /rong curr5t be made to fl[ pa/ ! end ( a spit1 x may cut away its extremity & rebuild ! mat]ials into a small] spit1 jo9+ ! ma9 "o at an angle4 ,?is gives rise to a hook 7,fig4 #cae74 ,successive /orms may develop successive hooks along ! side ( a gr[+ spit4 ,! end ( a hook may be s ext5d$ z to jo9 ! ma9l&1 :5 x becomes a loop4 ,wave-built t]races4--,"u ! influ5ce ( (f-%ore curr5ts1 littoral curr5ts may be drawn f ! coa/-l9e4 ,if su* a curr5t cont9ues z a well-def9$ surface-curr5t1 x builds a spit1 b if x spreads1 x t5ds to build a t]race4 ,! accumulation !n is n at ! end ( a bea*1 z 9 ! case ( a spit1 b on its side1 & ! result ( ! deposition is to c>ry ! bea* seaw>d4 ,! und]t[ abets ! process4 ,! wid5$ bea* is a wave-built t]race4 ,! wave-built t]race (t5 bord]s ! wave-cut t]race along its seaw>d m>g9 7,figs4 #cjc & #cah74 ,) ! help ( waves1 ! surface ( ! t]race may be built up into l& by ! expansion ( ! cre/ ( ! bea*4 ,t]race-cutt+ & t]race-build+ are bo? involv$ 9 ! developm5t ( ! cont95tal %elves4 ,bea* ridges1 spits1 b>s1 etc41 l sea-cliffs & wave-cut t]races1 are (t5 pres]v$ aft] ! relative level ( sea & l& has *ang$4 ,if ! %ore has ris51 relatively or absolutely1 ^! features are reli$ on z evid5ces ( ! *ange4 ,if %ore features be subm]g$ in/ead ( elevat$1 !y furni% less accessible1 ?\gh n less real1 evid5ce ( ! *ange ( level4 ,simil> features ab\t lakes h a l significance1 b 9 ?is case x is (t5 demon/rable t x is ! wat] r ?an ! l& :i* has *ang$ its level4 ,effect ( ,%ore-deposition on ,coa/al ,configuration4 ,! t5d5cy ( %ore-deposition is to cut (f bays & to /raight5 & simplify ! %ore-l9es4 ,?is is abundantly illu/rat$ along ! ,atlantic & ,gulf coa/s ( ! ,unit$ ,/ates 7see ,fig4 #cai & ,pl4 ,,xxii74 ,x is to be not$1 h[ev]1 t 9 ! simplification ( ! %ore-l9e ?r\gh deposition1 ! initial /ages (t5 result 9 great irregul>ity 7,fig4 #cbj & ,pl4 ,,xxiii74 ,9 "s cases1 ! irregul>ities are n tempor>y4 ,?us deltas 7p4 #aih71 ?\gh n :olly ! "w ( sea- 7or lake-7 wat]1 (t5 con/itute irregul>ities ( a m or less p]man5t nature4 ,?is is ! case :]e !y project beyond ! g5]al tr5d ( ! coa/-l9e4 ,:]e1 on ! o!r h&1 !y are built at ! heads ( bays1 !y t5d to simplify ! coa/-l9e by oblit]at+ ! ind5tation4 ,! delta at ! head ( ! ,gulf ( ,cali=nia is an example4 ,s too is ! delta ( ! ,mississippi1 ! real head ( :i* is f> above ! pres5t deb\*ure ( ! /ream4 ,! =m ( ! delta 9 gr\nd-plan dep5ds on ! horizontal configuration ( ! coa/ :]e x is develop$1 on ! /r5g? ( ! waves & %ore-curr5ts1 & on _! relation to ! am\nt ( detritus contribut$ by ! /ream conc]n$4 ,good illu/rations are furni%$ by ! ,gulf ( ,mexico :]e ! deltas ( ! ,mississippi & ,rio ,gr&e are 9 contra/4 ,s f> z conc]ns ! v]tical configuration ( coa/s1 erosion & deposition are 9 contra/1 = :ile ! =m] t5ds to develop /eep1 irregul>1 & (t5 high slopes 7p4 #cdi7 f ! l& to ! sea1 ! latt] t5ds to develop g5tle1 regul>1 & l[ ones4 ,a p>tial exception to ! latt] "p ( ?is g5]al /atem5t comes ab\t ?r\gh ! build+ ( dunes1 ! mat]ial = :i* is furni%$ by ! waves4 ,,summ>y ,,( ,,coa/al ,,irregul>ities4 ,! horizontal irregul>ities ( coa/s are bo? l>ge & small4 ,"s ( !m1 l ,florida1 ,s&y ,hook1 etc41 consi/ prim>ily ( projections ( l& into ! sea2 o!rs1 l ,*esapeake ,bay1 ! ,gulf ( ,mexico1 & ,puget ,s\nd1 are projections ( ! sea into ! l&2 :ile /ill o!rs1 l ! ,gulf ( ,cali=nia & its associat$ p59sula1 _c readily be put 9 ei!r ( ! =ego+ classes4 ,"s ( ! irregul>ities ( ! l& bord]1 su* z ,yucatan1 are m or less ne>ly normal to ! g5]al tr5d ( ! coa/ :i* !y affect1 :ile o!rs1 su* z ! 8bea*es0 along ! ,atlantic & ,gulf coa/s ( ! ,unit$ ,/ates 7,figs4 #cai & #cbj71 are m or less ne>ly p>allel ) x4 ,"s ( ! irregul>ities1 especially "s ( ! small ones1 are m or less angul> 9 _! outl9e 7,pl4 ,,xx & p>ts ( ,fig4 #b1 ,pl4 ,,xxii71 :ile o!rs are b\nd$ by curves in/ead4 ,9 _m cases m ?an "o factor has be5 involv$ 9 ! developm5t ( irregul>ities4 ,9 ! case ( great irregul>ities1 dia/rophism has g5]ally be5 ! dom9ant factor4 ,! ,gulf ( ,mexico & ! ,m$it]ranean ,sea p]haps repres5t diff]5tial subsid5ce1 :ile ,florida & ! ,ib]ian p59sula repres5t diff]5tial uplift 7relative1 ?\gh p]haps n absolute74 ,! n>r[ bays :i* ind5t _m coa/s g5]ally repres5t ! subsid5ce ( a region previ\sly affect$ by valleys 7,fig4 #big74 ,_m ( !m1 su* z ,n>ragansett1 ,delaw>e1 & ,*esapeake ,bays1 are prim>ily ! dr[n$ ends ( riv] valleys1 :ile o!rs1 su* z ,puget ,s\nd1#afg are prim>ily /ructural valleys 7syncl9es74 ,_m ( ! long & n>r[ bays or fiords common 9 ! high latitudes ( ,nor? ,am]ica & ,europe 7,fig4 #bff1 p4 #bic7 appe> to be ! dr[n$ ends ( valleys previ\sly deep5$ by glaci]s4 ,! dr[n$ ends ( riv] canyons1 & ! subm]g$ p>ts ( valleys excavat$ 7n sunk7 b5ea? ! sea by glaci]s1 w\ld also be fiords4 ,illu/ration3 ,,plate ,,xxiii4 ,fig4 #a4 ,,massa*usetts4 ,u4 ,s4 ,geol4 ,surv4 ,fig4 #b4 ,,ma9e4 ,u4 ,s4 ,geol4 ,surv4 ,illu/ration3 ,,plate ,,xxiv4 ,,portion ,,( ,,! ,,coa/ ,,( ,,ma9e4 ,u4 ,s4 ,geol4 ,surv4 ,! processes :i* develop coa/al ind5tations1 toge!r ) ! antec$5t subarial & ! subsequ5t wave gradation1 acc\nt = mo/ ( ! isl&s :i* affect ind5t$ coa/s4 ,"s ( !m are high & "s l[ = reasons :i* w be readily und]/ood4 ,! long n>r[ belts ( l& con/itut+ irregul>ities p>allel to ! g5]al tr5d ( ! coa/ 7,figs4 #cai & #cbj7 are usually ! result ( deposition 9 %all[ wat]4 ,!y are usually s& or coral reefs1 built up above wat]-level by waves4 ,! deposits at ! deb\*ures ( /reams give rise to project+ deltas4 ,mo/ small irregul>ities ( angul> =m1 especially if high 7,pl4 ,,xx71 indicate wave-erosion1 & _! details ( =m are det]m9$ by ! /ructure ( ! rock along %ore1 :ile mo/ irregul>ities ( curv$ outl9e involve some?+ ( %ore-deposition1 if n due :olly to x4 ,glaciation1 or glaciation & subsid5ce1 may also give rise to p59sulas1 capes1 & isl&s ( curv$ outl9es 7,pl4 ,,xxiv1 coa/ ( ,ma9e74 ,curv+ outl9es may1 h[ev]1 be develop$ by erosion alone 9 weak rock /ructures4 ,?is is illu/rat$ by ! weak rock /ructures 7clay1 s&1 etc47 ( mo/ ( ! ,atlantic coa/al pla94 ,?us inspection ( ! horizontal configuration ( coa/s w (t5 indicate ! processes :i* h be5 dom9ant !re 9 rec5t times4 ,on ! o!r h&1 ! int]pretations ( _m coa/al irregul>ities1 su* z ,hudson ,bay1 ,puget ,s\nd1 ! ,gulf ( ,cali=nia1 ! ,baltic ,sea1 etc41 are n to be read f ! map4 ,9 su* cases1 dia/rophism & gradation h usually cop]at$1 b ! relative importance ( ! two processes c only be det]m9$ by detail$ /udy 9 ! field4 ,:5 x is rememb]$ t ! t5d5cy ( %ore-erosion is to r$uce great irregul>ities ( horizontal configuration1 ?\gh n to oblit]ate small ones if ! coa/ be het]og5e\s 9 composition 7p4 #cec71 & t ! t5d5cy ( %ore-deposition is also to regul>ity1 x is cle> t ! great irregul>ities ( coa/-l9es are due nei!r to %ore-erosion nor to %ore-deposition1 ?\gh m9or ones may be due to ei!r4 ,,! ,,"w ,,( ,,ocean-,,curr5ts4 ,z ag5ts ( erosion1 ocean-curr5ts are n1 9 g5]al1 ( great importance4 ,curr5ts :i* rea* ! bottom are comp>able1 9 _! effects1 to riv]s ( ! same velocity & volume2 b mo/ ocean-curr5ts d n t\* bottom1 &1 !re=e1 d n erode x4 ,:]e ! curr5t agitates ! bottom s5sibly1 z x (t5 does 9 %all[ wat]1 ! bottom is abrad$1 & 9 ! lee ( su* places x is d\btless aggrad$4 ,s9ce ocean-curr5ts d n1 = ! mo/ "p1 fl[ 9 %all[ wat]1 _! erosive "w is1 on ! :ole1 relatively slight2 b :]e !y are =c$ ?r\gh n>r[ & %all[ passageways1 _! abrasive "w may be consid]able4 ,?us ! ,gulf ,/ream1 :]e x issues f ! ,gulf1 has a velocity ( f\r or five miles p] h\r1 & its %all[ & n>r[ *annel is curr5t-swept4 ,a r\gh te/ ( ! abrasive "w ( an ocean-curr5t is f\nd 9 ! nature ( ! bottom b5ea? x4 ,if ?is be h>d1 x indicates t ! loose s$im5t on ! floor ( ! ocean has be5 swept away1 :ile ! pres5ce ( f9e detritus indicates t ! curr5t is n we>+4 ,?us ! abrasive p[] ( ! ,gulf ,/ream is kn[n to cont9ue some:at beyond its n>r[ *annel1 = on ! ,blake plateau 7betwe5 ! ,bahamas & ,cape ,hatt]as71 :]e ! wat] is #fjj fa?oms & less 9 dep?1 8! bottom ( ! ,gulf ,/ream 444 is swept clean ( lime & ooze & is ne>ly b>r5 ( animal life40#afh ,o!r illu/rations ( ! erosive p[] ( curr5ts h be5 not$ ne> ,gibralt> 9 wat] #ejj fa?oms deep1 & betwe5 ! ,can>y ,isl&s at dep?s ( #ajjj fa?oms4#afi ,9 spite ( ^! examples1 & ( _m o!rs :i* probably exi/ 9 simil> situations1 x yet rema9s true t ocean-curr5ts are on ! :ole b feeble ag5ts ( erosion4 ,z ag5ts ( transportation1 ocean-curr5ts are sc>cely m important ?an z ag5ts ( corrasion1 = !y transport only :at !y erode1 if ! life :i* inhabits !m be left out ( consid]ation4 ,?is phase ( _! "w has probably be5 exagg]at$ ?r\gh a confusion ( transport+ en]gy & actual transportation4 ,ocean-curr5ts :i* d n t\* bottom roll no s$im5t & c>ry only :at may be held 9 susp5sion4 ,a riv]'s p[] ( transport+ s$im5t 9 susp5sion is due l>gely to ! cross-curr5ts occasion$ by ! unev5ness ( its resi/ant bottom 7p4 #aag74 ,if a p>ticle ( mud 9 susp5sion 9 a riv] drops to ! bottom1 z x frequ5tly does1 x may be pick$ up aga9 & c>ri$ =w>d4 ,if1 on ! o!r h&1 a p>ticle 9 susp5sion 9 an ocean-curr5t once escapes ! mov+ wat] by settl+ ?r\gh x1 ! curr5t :i* does n drag bottom has no *ance to pick x up aga94 ,v f9e s$im5t may be c>ri$ by an ocean-curr5t f> beyond ! po9t :]e x 0 acquir$1 b curr5ts :i* d n t\* bottom are r>ely /rong en\gh to hold any b ! f9e/ mat]ial = any consid]able l5g? ( "t4 ,z transport]s ( s$im5t1 !re=e1 ocean-curr5ts are at a great disadvantage z comp>$ ) riv]s4 ,h[ readily p>ticles ( extreme f95ess may be kept 9 susp5sion1 & h[ little agitation is necess>y to keep !m f s9k+1 is %[n by ! exp]im5ts ( ,sorby1 :o %[$ t :ile a s& gra9 ( an in* 9 diamet] w settle "o foot p] second 9 /ill wat]1 f9e p>ticles ( clay require days to s9k ?r\gh ! same di/ance4 ,! ,*all5g] f\nd f9e s$im5t d]iv$ f ! l& #djj miles f ! coa/ ( ,africa1 & t n opposite ! deb\*ure ( any l>ge riv]4 ,s$im5t settles m readily 9 salt wat] ?an 9 fre%1 despite ! fact t ! =m] is heavi]4 ,?is is presumably because ! salt dim9i%es ! cohesion ( ! wat]4 ,deposition by ocean-curr5ts is limit$ by _! transportation4 ,only :]e !y erode _! bottoms d !y ga!r co>se mat]ials1 & only 9 ! lee ( su* places are _! deposits co>se4 ,s9ce ! mat]ial :i* !y c>ry is g5]ally f9e1 x is widely di/ribut$ be=e deposition4 ,ocean-curr5ts h little influ5ce on ! configuration ( coa/-l9es4 ,,deposits ,,on ,,! ,,ocean-,,b$4 ,some?+ has already be5 said conc]n+ ! s$im5ts :i* accumulate 9 ! %all[ wat]s along %ores2 b ! area ( m>9e s$im5tation is z ext5sive z ! ocean itself1 & ! deposits mu/ n[ be review$ f ano!r po9t ( view4 ,oceanic deposits may be conv5i5tly divid$ into two *ief gr\ps1 dep5d5t on ! dep? ( ! wat] 9 :i* !y are made4#agj ,^! gr\ps are 7#a7 %all[-wat] deposits1 made 9 wat] less ?an "s su* dep? z #ajj fa?oms1 & 7#b7 deep-sea deposits1 laid d[n 9 wat] ( great] dep?4 ,! selection ( ! #ajj-;fa?om l9e z ! divid+ dep? is less arbitr>y ?an x seems1 = pass+ outw>d f ! %ore1 x is at ab\t ?is dep? t ! bottom ceases to be commonly di/urb$ by ! action ( curr5ts & waves2 t sunlight & vegetable life cease to be important at ! bottom2 & t ! co>s] s$im5ts :i* pr$om9ate along %ore give place1 z a rule1 to muds & oozes4 ,fur!rmore1 ! #ajj-;fa?om l9e 7or "s l9e v ne> x7 is an important "o 9 ! physical relief ( ! globe1 = x appe>s to m>k1 approximately1 ! junction ( cont95tal plateaus & ocean-bas9s4 ,only because ! latt] are a little ov]-full does ! wat] run ov] _! rims1 cov]+ ab\t #aj1jjj1jjj squ>e miles ( ! bord]s ( ! cont95ts1 conv]t+ !m f l& into epicont95tal seas4 ,aside f ! deposits made by organisms1 %all[-wat] deposits are divisible into two gr\ps--7a7 ^? imm$iately along ! %ore1 ! littoral deposits1 & 7b7 ^? made betwe5 ! littoral zone & ! #ajj-;fa?om l9e4 ,bo? are t]rig5\s4 ,! deep-sea deposits likewise are divisible into two gr\ps1 7a7 t]rig5\s deposits =m$ close to l&1 & made up *iefly ( mat]ials d]iv$ imm$iately f ! dis9tegration ( l& =mations2 & 7b7 ! pelagic deposits1 made up *iefly ( ! rema9s ( pelagic organisms & ! ultimate products aris+ f ! decomposition ( rocks & m9]als4 ,! =m] pr$om9ate 9 ! less deep wat]s relatively ne> %ore2 ! latt] 9 ! deep] wat] f> f l&4 ,! %all[- & deep-wat] deposits grade into ea* o!r 9 a belt along ! #ajj-;fa?om l9e4 ,%all[-wat] ,deposits4 ,littoral deposits4--,! littoral zone is ! zone betwe5 high- & l[-wat] m>ks4 ,x is ! zone 9 :i* b[ld]s1 gravels1 s&s1 & all co>s] mat]ials accumulate1 ?\gh muds are occasionally met ) 9 %elt]$ e/u>ies4 ,g5]ally speak+1 ! nature ( ^! deposits is det]m9$ by ! "* ( ! adjo9+ l&s & ! nature ( ! local organisms4 8,! heavi] mat]ials br\ght by riv]s f high t]re/rial regions1 or ?r[n up by ! tides & waves ( ! sea1 are "h arrang$ ) great div]sity ( /ratification ?r\gh ! alt]nate play ( ! w9ds & waves4 ,twice 9 ! tw5ty-f\r h\rs ! littoral zone is cov]$ by wat] & expos$ to ! direct rays ( ! sun or ! cool+ effects ( ! night4 ,!re is a great range ( temp]ature2 me*anical ag5cies produce _! maximum effects10#aga & physical conditions 9 g5]al are mo/ v>i$4 ,/ill great] div]sity is introduc$ by ! fact t ! zone is inhabit$ by bo? m>9e & t]re/rial organisms1 :ile ! evaporation ( ! sea-wat] :i* fl[s ov] tidal m>%es & lagoons leads to ! =mation ( sal9e deposits4 ,if ! l5g? ( ! coa/-l9es ( ! _w be tak5 at #abe1jjj miles 7ab\t #bjj1jjj kilomet]s71 & ! av]age wid? ( ?is zone at half a mile1 ^! deposits are n[ =m+ ov] an area ( #fb1ejj squ>e miles 7ab\t #afj1jjj squ>e kilomet]s7 ( ! e>?'s surface4 ,non-littoral1 me*anical deposits 9 %all[ wat]4--,^! deposits are laid d[n 9 ! zone ( ! ocean betwe5 l[-wat] m>k & ! #ajj-;fa?om l9e4 ,!y cov] ab\t #aj1jjj1jjj squ>e miles4#agb ,_! composition is mu* ! same z t ( ! littoral deposits1 ) :i* !y are cont9u\s1 ?\gh on ! :ole !y are f9]4 ,at _! l[] limit !y pass ins5sibly into ! f9e deposits ( ! deep sea4 ,co>se mat]ial1 su* z gravel & s&1 prevails1 ?\gh 9 special situations1 su* z depressions & inclos$ bas9s1 muddy deposits are f\nd4 ,:ile "s ( ! deposits are :olly compos$ ( inorganic dbris1 organic rema9s are freely m+l$ ) o!rs4 ,! me*anical effects ( tides1 curr5ts1 & waves are ev]y:]e pres5t1 b become less & less well m>k$ z ! #ajj-;fa?om l9e is approa*$4 ,! =ms ( vegetable & animal life are num]\s1 ?\gh ! =m] decrease z dep?s :i* exclude ! sunlight are approa*$4 ,bo? littoral deposits & deposits 9 %all[ wat] outside ! littoral zone h already be5 ref]r$ to 9 connection ) ! "w ( waves & curr5ts 7pp4 #cee-ff74 ,a few additional po9ts only ne$ "h be add$4 ,illu/ration3 ,figs4 #cba & #cbb4--;,diagrams %[+ h[ %all[-wat] deposits may atta9 consid]able dep? by ! %ift+ ( ! zone ( deposition seaw>d4 ,illu/ration3 ,fig4 #cbc4--;,diagram %[+ ! int]w$g+ ( gravel-1 s&-1 & mud-b$s4 ,9 g5]al ! co>s] s$im5ts are lodg$ ne> %ore & ^? f>!r f ! l& become progressively f9]4 ,ev5 ! co>s] "p ( ! mat]ial c>ri$ 9 susp5sion by ! und]t[ is p>tly left 9 ! %all[ wat]4 ,on ! o!r h&1 waves ( exceptional /r5g? may c>ry co>se mat]ial into wat] ( "s dep?4 ,?us co>se %+le 7gravel7 & ev5 b[ld]s h be5 f\nd at dep?s ( #aj fa?oms4#agc ,co>se deposits may ext5d f> out f l& if ! waves are /rong1 & especially if ! wat] is %all[1 & s9ce ! zone ( %all[ wat] may be ext5d$ seaw>d by ! aggradation ( ! bottom1 %all[-wat] deposits may cov] ext5sive areas4 ,!y may become deep at ! same "t1 = z ! out] bord] ( ! %all[-wat] zone is %ift$ seaw>d by aggradation1 ! v]tical space to be fill$ becomes great] 7comp>e ,figs4 #cba & #cbb74 ,aga91 if ! coa/ be s9k+1 new deposits ( co>se mat]ial may be made on old] ones4 ,9 ?is way also great ?icknesses ( s$im5t may be accumulat$1 all p>ts ( :i* 7 deposit$ 9 %all[ wat]4 ,! great ?ickness ( "s ( ! conglom]ate b$s ( ! pa/ %[s h[ f> ?is process may g4 ,illu/ration3 ,fig4 #cbd4--,ripple-m>ks4 ,illu/ration3 ,fig4 #cbe4--,rill-m>ks resembl+ impressions ( seawe$s4 ,bea* at ,noyes ,po9t1 ,r4 ,i4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cbf4--,rill-m>ks4 ,same locality z #cbe4 7,walcott47 ,z a rule1 no def9ite l9e m>ks ! seaw>d t]m9us ( ! co>se detritus1 s9ce co>se mat]ial is c>ri$ f>!r out :5 ! waves run high 7& ! und]t[ is /rong7 ?an :5 !y are feeble4 ,9 calm wea!r1 !re=e1 f9e s$im5t may be deposit$ :]e co>se _h be5 laid d[n 9 ! prec$+ /orm1 only to be cov]$ 9 turn by o!r deposits ( a diff]5t "*4 ,?us gravel grades (f into s&1 ) m or less ov]lapp+ or int]w$g+1 & s& grades (f into silt 9 ! same way4 ,?is is diagrammatically illu/rat$ by ,fig4 #cbc4 ,*>act]i/ics ( %all[-wat] deposits4--,cla/ic s$im5ts laid d[n 9 %all[ wat] h sev]al di/9ctive *>act]i/ics4 ,:ile !y are1 9 ! aggregate1 co>se1 !y are *>act]iz$ by frequ5t v>iations 9 co>s5ess4 ,! surfaces ( successive b$s are likely to be ripple- & rill-m>k$ 7,figs4 #cbd1 #cbe1 #cbf71 & cross-b$d+ 7,fig4 #cbg7 is ( common occurr5ce4 ,clayey s$im5ts accumulat$ betwe5 high & l[ wat] are (t5 sun-crack$ 7,fig4 #cbh71 & ! tracks ( l& animals are sometimes pres]v$ on _! surfaces4 ,%all[-wat] deposits (t5 conta9 fossils ( organisms :i* live 9 wat]s ( slight dep?4 ,^! *>act]i/ics are suffici5t to diff]5tiate s$im5t>y =mations made 9 %all[ wat] f ^? made 9 deep wat]1 ev5 aft] !y h be5 conv]t$ into solid rock & aft] ! rock has em]g$ f ! sea4 ,_m ( ^! *>act]i/ics are1 h[ev]1 %>$ by deposits made by /reams on ! l&4 ,subarial & lacu/r9e s$im5ts are usually di/+ui%able f ^? made 9 ! sea by _! fossils1 & sometimes by _! di/ribution4 ,illu/ration3 ,fig4 #cbg4--;,cross-b$d+4 7,gilb]t47 ,illu/ration3 ,fig4 #cbh4--,sun-cracks4 ,^! cracks 7 on ! mud-flats ( ! ,miss\ri a few miles above ,kansas ,city1 b ! sun-cracks on %ore-deposits are n ess5tially diff]5t4 7,calv947 ,topography ( %all[-wat] deposits4--,! %all[-wat] deposits h1 on ! :ole1 a r plane surface1 ?\gh !re are "s notable dep>tures f flatness4 ,! /eep slopes ( ! delta fronts & ( wave-built t]races h already be5 spok5 (4 ,b>ri]s (t5 %ut 9 depressions1 & ! disposition ( ! mat]ial deposit$ is sometimes unev51 ow+ to %ore & tidal curr5ts4 ,! result is t ! surface ( ! %all[-wat] deposits is (t5 affect$ by l[ elevations & by %all[ depressions4 ,! elevations & depressions may be elongate1 circul>1 or irregul> 9 =m4 ,^! g5]al facts are %[n 9 ,figs4 #cai1 #cbj1 & #cbi4 ,?is topography is sometimes pres]v$ on newly em]g$ l&s1 z at v>i\s po9ts on ! ,coa/al ,pla9 ( ! ,unit$ ,/ates4 ,illu/ration3 ,fig4 #cbi4--;,irregul>ities ( topography ( %all[-wat] deposits4 ,! dep?s ( ! wat] are %[n 9 fa?oms4 7,*>t ( ,c4 & ,g4 ,surv47 ,*emical & organic deposits4--,!re is no %>p l9e ( di/9ction betwe5 ! deposits usually class$ z *emical & ^? reg>d$ z organic4 ,! latt] are *emical 9 ! broad] s5se ( ! t]m1 b z !y are imm$iately associat$ ) life & are dep5d5t ^u x1 x is a matt] ( practical conv5i5ce to sep>ate !m4 ,aside f ! organic deposits1 ! *emical deposits made 9 %all[ sea-wat] embrace 7#a7 ^? due to reactions betwe5 con/itu5ts s br\ght toge!r t new & insoluble comp\nds are =m$ & precipitat$1 & 7#b7 ^? due to evaporation4 ,! po9ts ( saturation = ! v>i\s sub/ances dissolv$ 9 sea-wat] are rea*$ at diff]5t /ages1 & h5ce !y are deposit$ m or less 9 succession4 ,! *emical deposits made 9 ! %all[ wat] ( ! sea1 or 9 %all[ bodies ( wat] isolat$ f ! sea1 are *iefly simple precipitates result+ f evaporation2 b new comb9ations are sometimes made 9 ! process ( conc5tration & precipitation4 ,all sub/ances 9 solution are necess>ily precipitat$ on complete evaporation1 b s9ce ! sea-wat] is 9 g5]al f> f saturation1 s f> z all its lead+ salts are conc]n$1 only a few are ?r[n d[n 9 quantity suffici5t to h geological importance :]e evaporation is incomplete4 ,! lead+ deposits are lime c>bonate 7,ca,c,o71 lime sulphate 7gypsum1 ,ca,s,o1#b;,h,o71 common salt 7rock-salt1 ,na,cl71 & ! magnesium salts1 usually ! *lorides & sulphates1 :i* are lat] *ang$ to c>bonates4 ,9 inve/igations on ,m$it]ranean wat]#agd :i* _h an initial d5sity ( #a4jb1 no deposit took place until conc5tration by evaporation _h br\ght ! wat] to a specific gravity ( #a4je4 ,betwe5 ?is d5sity & t ( #a4ac1 lime c>bonate & "s iron oxide 7 deposit$4 ,betwe5 #a4ac & #a4bb1 lime sulphate 0 ! mo/ abundant precipitate1 :ile betwe5 #a4bb & #a4ca1 #ie ( ! deposit 0 common salt4 ,) /ill fur!r conc5tration1 ! rema9+ sub/ances 9 solution1 especially ! magnesium salts1 7 ?r[n d[n4 ,:ile !re is some:at m ?an t5 times z mu* lime sulphate z lime c>bonate 9 ! ocean 7p4 #cbd71 ! deposits ( ! c>bonate 7includ+ ! organic7 h be5 v mu* great] ?an ^? ( ! sulphate4 ,?is is due p>tly to ! fact t ! sulphate is mu* m soluble 9 natural wat]s ?an ! c>bonate4 ,riv]s br+ mu* m c>bonate ?an sulphate to ! sea1 s t ! po9t ( saturation = ! sulphate w\ld normally be rea*$ mu* lat] ?an t ( ! c>bonate4 ,! m important fact1 h[ev]1 is t m>9e plants & animals use lime c>bonate freely = skeletal & h\s+ purposes4 ,x is held by "s t !y get _! lime f ! sulphate1 b if s !y conv]t x into c>bonate be=e x takes ! =m ( %ells1 coral1 etc41 ! sulphuric acid set free 9 ! process reproduc+1 directly or indirectly1 m sulphate4 ,! secretion ( lime c>bonate by organisms is n dep5d5t on ! saturation ( ! wat]1 b may be c>ri$ on :5 ! am\nt 9 solution is v small4 ,!re c be little d\bt t ! *ief deposits ( lime c>bonate h be5 & are be+ made ?r\gh ! ag5cy ( plants & animals 9 ! =m ( %ells1 coral1 bones1 tee?1 & o!r devices = support+1 /iff5+1 h\s+1 protect+1 & arm+ !mselves2 b :ile x is agre$ t ! l>g] "p ( ! lime c>bonate deposit$ 9 ! op5 sea is ( organic orig91 x is equally cle> t 9 clos$ seas subject to conc5tration f evaporation1 simple precipitation takes place freely4 ,!re is "s diff]5ce ( op9ion z to ! importance ( ^! two classes ( deposits1 pa/ & pres5t4 ,! debat$ po9t is :e!r simple precipitation takes place 9 any appreciable degree "u ! usual oceanic conditions4 ,!re is mu* m evid5ce ( solution by sea-wat] ?an ( precipitation f x4 ,! ocean appe>s to be "u-saturat$ ) lime c>bonate on ! :ole1 ?\gh x is /ill possible t deposition may take place 9 favorable situations1 z1 = example1 :]e ! v calc>e\s wat]s ( riv]s are spread out 9 ?9 %eets on ! surface ( ! heavi] salt wat]1 & ?us expos$ to exceptional evaporation1 or :]e !re is v exceptional agitation & aration4#age ,gypsum appe>s to be deposit$ 9 quantity only 9 ! clos$ bas9s ( arid regions :]e conc5tration rea*es an advanc$ /ate4 ,s9ce normal sea-wat] is f> f saturation ) common salt1 ! latt] is precipitat$ only 9 lagoons1 clos$ seas1 or o!r situations favorable to great conc5tration4 ,?is is usually a*iev$ only 9 notably arid regions1 & 9 bas9s t receive little or no dra9age f ! l&4 ,deposits ( salt usually1 !re=e1 signify highly arid conditions1 & :]e !y occur ov] wide ranges 9 latitude & longitude1 z 9 c]ta9 p]iods ( ! pa/1 unusual aridity is inf]r$4 ,:]e conf9$ to limit$ areas1 _! climatic significance is less1 = topographic conditions may det]m9e local aridity4 ,! total area :]e salt is n[ be+ precipitat$ is small1 ?\gh on ! :ole ! pres5t is probably to be reg>d$ z a r arid p]iod ( ! e>?'s hi/ory4 ,on ! o!r h&1 anci5t deposits ( salt pres]v$ 9 ! s$im5t>y /rata %[ t ! area ( salt deposition has be5 mu* m consid]able ?an n[ at "o "t & ano!r 9 ! e>?'s hi/ory4 ,! salt & gypsum deposits ( ! pa/ seem1 !re=e1 to tell an int]e/+ tale ( ! climates ( ! pa/4 ,! magnesium salts are among ! la/ to be ?r[n d[n z ! sea-wat] is evaporat$1 & !y mo/ commonly take ! =m ( sulphates & *lorides4 ,!y (t5 =m d\ble salts ) potassium1 a relatively small & soluble con/itu5t ( sea-wat]4 ,9 ! artificial evaporation ( salt wat] to obta9 common salt1 ! process is usually /opp$ be=e ! saturation-po9t = ! magnesium salts is rea*$1 & ! residue1 ! 8"m-liquor10 or 8bitt]n10 is drawn (f to prev5t ^! 8bitt]0 salts f mix+ ) ! common salt4 ,! magnesium salts are among ! la/ to be precipitat$1 n only because !y are readily soluble1 b because _! quantity is small2 yet 9 ! orig9al rock f :i* all ! sea-salts came1 !re is at lea/ z mu* magnesium z sodium1 :ile 9 ! sea !re is ab\t five times z mu* sodium z magnesium4 ,j :at becomes ( ! rema9+ magnesium is n yet well und]/ood4 ,x has a notable disposition to =m d\ble salts ) "s o!r con/itu5t1 z not$ above4 ,9 ! e>li] m>9e /rata1 dolomite1 t is1 lime/one compos$ p>tly or :olly ( ! d\ble c>bonate ( lime & magnesia1 7,ca,mg7,,co1 ab\nds4 ,?is appe>s to h be5 =m$ by a gradual sub/itution ( molecules ( magnesium = ^? ( calcium1 b j h[ & :5 & :y x 0 done has n be5 fully work$ out4 ,x appe>s to be a case :]e ! sal9e matt] ( ! sea made its contribution to ! s$im5t>y deposits by *emical reaction ^u !m1 r ?an by precipitation because ( saturation4 ,! relatively small am\nt ( pota% 9 ! sea-wat] is probably due to its disposition to rema9 unit$ ) ! clays & e>?s ( ! mantle rock & ( ! %aley deposits4 ,to "s ext5t ! salts 9 solution act directly on ! e>?y matt] br\ght d[n into ! sea by riv]s1 b :]e s$im5tation is rapid1 z x (t5 is 9 %all[ wat]1 ?is action is limit$ & obscure4 ,9 ! ma91 ! ocean-wat]s protect ! s$im5ts f wea!r+ & simil> *anges1 except z organic matt] buri$ ) !m induces *ange4 ,:ile ! lime deposits are by f> ! greate/ ( ! *emical & organic deposits ( ! sea1 plants & animals also secrete notable quantities ( silica4 ,silica deposits ( organic orig9 are relatively mu* m important 9 ! deep sea ?an 9 %all[ wat]1 & w be m5tion$ 9 t connection4 ,lime/one4--,some?+ conc]n+ ! orig9 ( lime/one has already be5 giv5 9 ! prec$+ p>agraphs1 b because ( ! importance ( ?is =mation1 x may be add$ by way ( summ>y t %all[ seas free1 or ne>ly free1 f t]rig5\s s$im5t1 & ab\nd+ 9 lime-secret+ life1 furni% ! conditions = ne>ly pure deposits ( lime/one1 & t mo/ ( ! lime/one )9 ! areas ( ! pres5t cont95ts appe>s to h orig9at$ "u su* conditions4 ,! common notion t lime/one is normally a deep-wat] =mation is a s]i\s error4 ,al?\gh lime/ones are =m$ 9 deep z well z 9 %all[ wat]s1 by f> ! m important classes ( lime-secret+ organisms are photoba?ic1 i4e4 are limit$ to ! dep?s to :i* light p5etrates4 ,9 ! %all[ wat]s1 ^! plants & animals are 9 "p free & 9 "p atta*$4 ,)9 ! areas ( deep wat] !y are free & at ! surface1 & _! rema9s drop to ! bottom1 if n soon] dissolv$4 ,b few =ms live on ! deep1 d>k1 cold bottoms ( abysmal dep?s4 ,cle> wat]s1 free f abundant t]rig5\s s$im5ts & ab\nd+ 9 lime-secret+ life1 r ?an deep wat]s1 are1 !re=e1 ! mo/ favorable conditions = ! orig9 ( lime/one4 ,! purely *emical deposits ( lime/one are probably all ( %all[-wat] orig94 ,once made1 !y are subject to solution1 r$eposition1 & o!r mutations l o!r deposits4 ,z a result1 !y (t5 lose _m ( _! orig9al *>act]i/ics1 b en\gh usually rema9 to tell ! /ory ( _! orig94 ,deep-sea ,deposits4 ,contra/$ ) %all[-wat] deposits4--,! deep-sea deposits cov] ! ocean-bottom bel[ ! #ajj-;fa?om l9e4 ,_! area is consid]ably m ?an half ! e>?'s surface4 ,! *>act]i/ic deposits are muds1 organic oozes1 & clays1 :i* 9 _! physical *>act]i/ics are rem>kably uni=m4 ,9 regions ( float+ ice1 great] div]sity is introduc$ f ! v>i$ nature ( ! mat]ials :i* ! ice transports1 b gravels & s&s1 comp>able to ^? ( %all[ wat]1 are r>ely f\nd4 8,tides1 curr5ts1 & waves produce "s me*anical effects at ! upp] limits ( ! deep-sea region1 b on ! :ole !re is an abs5ce ( ! ph5om5a ( erosion1 & me*anical action w\ld appe> to be abs5t except 9 ! case ( subm>9e eruptions4 ,! dep? is too great = sunlight to p5etrate1 & vegetable life is limit$ to ! upp] zone4 ,animal life is pres5t 9 ! same zone & on ! bottom1 b abs5t or ne>ly s 9 ! middle dep?s4 ,! temp]ature 7at ! bottom7 is bel[ #dj ,fahr4 ?r\gh\t ! l>g] "p ( ! area1 & if subject to v>iation ) latitude or *ange ( season1 ^! *anges affect only ! dep?s imm$iately beyond ! #ajj-;fa?om l9e4 ,?r\gh\t ! :ole region !re is a v uni=m set ( conditions4 ,9 ! %all[-wat] & littoral zones1 ow+ to ! rapid accumulation & ! me*anical effects ( transportation & erosion1 ! effects ( *emical modification are n v app>5t 9 ! deposits2 b 9 deep-sea deposits1 9 consequ5ce ( ! less rapid rate ( accumulation1 abs5ce ( transport1 ! nature & small size ( ! p>ticles1 _m evid5t *emical reactions h tak5 place1 result+ 9 ! =mation 9 situ ( glauconite1 phosphatic & manganese nodules1 zeolites1 & o!r second>y products40#a ,) increas+ dep? & di/ance f ! %ore1 ! "* ( ! deposits und]goes a *ange4 ,!re is less & less mat]ial d]iv$ directly f ! l&1 & m 8amorph\s matt] aris+ f ! ultimate decomposition ( m9]als & rocks1 & accompani$1 9 all mod]ate dep?s1 by an increase relative ( ! rema9s ( pelagic organisms4 ,we ?us pass ins5sibly f ^? deep-sea deposits ( a t]re/rial orig91 :i* we call #8t]rig5\s1' to ^? deep-sea deposits d5om9at$ #8pelagic1' 9 :i* ! rema9s ( calc>e\s & silice\s organisms1 clays & o!r sub/ances ( second>y orig9 play ! pr9cipal rle40#agf ,! foll[+ table#agg %[s ! relations ( ! v>i\s gr\ps ( m>9e deposits4 #a4 ,deep-sea deposits beyond ,r$ clay ,i4 ,pelagic deposits #ajj fa?oms ,radiol>ian ooze =m$ 9 deep ,diatom ooze wat] remov$ ,globig]9a ooze f l&4 ,pt]opod ooze ,blue mud ,r$ mud ,gre5 mud ,volcanic mud ,,ii4 ,t]rig5\s ,coral mud deposits =m$ 9 deep & #b4 ,%all[-wat] deposits ,s&s1 gravels1 %all[ wat]1 betwe5 l[-wat] m>k muds1 etc4 mo/ly close & #ajj fa?oms to l&4 #c4 ,littoral deposits betwe5 ,s&s1 gravels1 high- & l[-wat] m>ks muds1 etc4 ,s\rces4--,! pelagic deposits are made up 9 "p ( mat]ials ( organic orig91 & 9 "p ( mat]ials ( inorganic orig94 ,! inorganic mat]ials may be ( me*anical or *emical orig94 ,me*anical pelagic deposits orig9ate 9 v>i\s ways4 ,!y may come 7#a7 f ! l& by ! ord9>y processes ( gradation1 7#b7 f volcanic v5ts1 or 7#c7 f extra-t]re/rial s\rces4 ,*emical deposits may be =m$ 7#a7 9 situ by ! *emical int]action ( sub/ances 9 ! sea-wat] on mat]ials ( organic & inorganic orig91 & 7#b7 by direct precipitation f ! sea-wat]4 ,me*anical inorganic deposits4--,! t]rig5\s mat]ials :i* rea* ! deep sea are1 z a rule1 only ! f9e/ products ( l& decay1 & are c>ri$ out by movem5ts ( wat] or by ! w9ds4 ,!y are n commonly recogniz$ 9 ! dr$g+s m ?an #bjj miles f ! %ore1 b opposite ! m\?s ( great riv]s !y ext5d mu* f>!r1--#ajjj miles 9 ! case ( ! ,amazon4 ,!y are especially abundant on ! slopes ( ! cont95tal %elves4 ,"h occur ! blue1 gre51 & r$ muds1 ) :i* are associat$ volcanic & coral muds4 ,! color ( ^! v>i\s muds is dep5d5t 9 "p on ! *anges :i* !y h und]gone s9ce _! deposition4 ,! gre5 muds usually conta9 en\gh glauconite to give !m _! color1 & are mo/ commonly f\nd (f bold coa/s :]e s$im5tation is n rapid4 ,! blue muds indicate lack ( oxidation1 or p]haps deoxidation4 ,r$ muds are n common1 ?\gh !y h be5 f\nd 9 "s situations4 ,9 g5]al1 ^! deposits are analog\s to c]ta9 %ales1 m>ls1 etc41 f\nd )9 ! cont95ts4 ,?\gh co>se mat]ials d]iv$ f ! l& are occasionally f\nd 9 ! deep-sea deposits1 _! pres5ce mu/ be look$ ^u z 9 "s s5se accid5tal4 ,occasional pebbles1 or ev5 b[ld]s1 are c>ri$ out into ! ocean entangl$ 9 ! roots ( float+ trees4 ,)9 limits1 too1 iceb]gs h c>ri$ out l& dbris1 ?\gh x is probable t transportation by ?is means has be5 exagg]at$4 ,! am\nt :i* iceb]gs might c>ry1 if fully load$1 is f> great] ?an ! am\nt :i* !y d c>ry4 ,( ! id5tifiable inorganic mat]ials 9 ! deep sea1 ! mo/ abundant are ( volcanic orig91 & among ^! ! mo/ common is pumice1 :i* is frequ5tly s light t x floats readily until x becomes wat]-logg$4 ,pieces ( pumice br\ght up by ! ,*all5g] & ?or\ghly dri$ 7 f\nd to float = mon?s 9 sea-wat] be=e settl+ ev5 ?r\gh ! dep? ( wat] conta9$ 9 ! vessel 9 :i* ! exp]im5t 0 p]=m$4#agh ,! next mo/ abundant sub/ance ( volcanic orig9 9 pelagic deposits is volcanic glass4 ,?is ranges f pieces ( ! size ( a walnut d[n to ! smalle/ fragm5ts1 :i* (t5 s]ve z c5t]s = concretions4 ,lapilli 7c9d]s7 & volcanic a% also are abundant 9 p>ts ( ! deep sea4 ,! di/ribution ( ^! volcanic products is ess5tially univ]sal1 ?\gh by no means uni=m4 ,"s ( !m are probably f subm>9e volcanoes4 ,! /udy ( ! deep sea deposits has reveal$ ! pres5ce ( _m nodules & gra9s :i* are believ$ to be ( extra-t]re/rial orig94 ,_m ( !m are magnetic4#agi ,! du/ ( c\ntless meteors :i* ent] ! atmosph]e daily settles on l& & sea alike1 & ent]s into ! s$im5t ( ! bottom ( ! latt]4 ,x is probably no m abundant 9 deep wat] ?an 9 %all[1 b x is relatively m important1 s9ce o!r s$im5tation is m meag]4 ,! numb] ( meteorites :i* ent] ! atmosph]e daily has be5 e/imat$ at f #ae1jjj1jjj to #bj1jjj1jjj4ahj ,if on ! av]age ! meteorites weigh t5 gra9s ea*1 probably a r high e/imate1 ! total am\nt ( extra-t]re/rial matt] rea*+ ! e>? ye>ly w\ld be #e1jjj to #g1jjj tons1 & some?+ l ?ree-f\r?s ( ?is mu/1 on ! av]age1 fall into ! sea4 ,b ev5 at ?is rate x w\ld take "s fifty billion ye>s to cov] ! sea-bottom ) a lay] "o foot 9 ?ickness4 ,organic con/itu5ts ( pelagic deposits4--,) increas+ di/ance f %ores1 & especially ) increas+ dep? ( wat]1 t]rig5\s deposits become less & less abundant1 & s$im5ts d]iv$ f pelagic life increase 9 relative importance4 ,beyond ! upp] "p ( ! out] slopes ( ! cont95tal %elves1 ! pelagic deposits are l>gely made up ( %ells & skeletons ( m>9e organisms :i* live 9 ! surface-wat]s4 ,pelagic molluscs1 =am9if]a1 & alg secrete %ells ( lime c>bonate1 :ile diatoms & radiol>ians secrete %ells ( silica4 ,:5 ! organisms die1 !y s9k to ! bottom ) _! %ells1 & ^! m9]al matt]s ( organic orig9 are m+l$ ) ! volcanic products :i* are univ]sal ov] ! sea-floor4 ,pelagic deposits ( organic orig9 are nam$ accord+ to _! *>act]i/ic con/itu5ts4 ,?us !re are pt]opod oozes1 globig]9a oozes1 diatom oozes1 radiol>ian oozes1 etc4#aha ,x is n to be und]/ood t ^! oozes are made up exclusively ( ! %ells :i* give !m _! names4 ,diatom ooze is an ooze 9 :i* diatom %ells are abundant1 n an ooze made up :olly ( diatom %ells2 & globig]9a ooze is an ooze 9 :i* globig]9a %ells are abundant1 ?\gh 9 _m cases !y d n make up ev5 ! bulk ( ! matt]4 ,:ile samples ( ^! v>i\s oozes might be select$ :i* are ?or\ghly di/9ct f "o ano!r1 !re are all gradations betwe5 !m1 s9ce pelagic life does n recognize b\nd>y-l9es4 ,x is a significant fact t ) increas+ dep? ! proportion ( lime c>bonate 9 ! ooze decreases4 ,?us 9 tropical regions remote f l& :]e ! dep?s are less ?an #fjj fa?oms1 ! c>bonate ( lime ( ! %ells ( pelagic organisms may con/itute #hj or #ij ( ! deposit4 ,) ! same surface conditions1 b ) increas+ dep?1 ! p]c5tage ( lime c>bonate decreases1 until at #bjjj fa?oms x is less ?an #fj2 at #bdjj fa?oms1 #cj1 & at #bfjj fa?oms1 #aj4 ,beyond ?is dep? !re are usually no m ?an traces ( c>bonate ( lime4 ,! data at h& %[ t ! p]c5tage ( lime c>bonate falls (f bel[ #bbjj fa?oms m rapidly ?an at less] dep?s4 ,:5 ! p]c5tage ( lime c>bonate becomes v l[1 ! calc>e\s oozes grade (f into ! r$ clay ) :i* ! sea-floor bel[ #bdjj to #bfjj fa?oms is cov]$4 ,*emical deposits4--,! *emical deposits ( ! deep sea are *iefly ! alt]ation products ( s$im5ts :i* rea* ! sea-bottom by me*anical means4 ,all s$im5t deposit$ 9 ! sea und]goes m or less *emical *ange1 b x is only :5 ! *ange is v consid]able t ! product is ref]r$ to ?is class4 ,:]e s$im5tation is rapid & ! s$im5t co>se1 ! *emical *ange is relatively slight2 b :]e ! s$im5tation is sl[ & ! s$im5t f9e1 ! *emical *ange is relatively great2 = ! long] exposure to ! sea-wat] & ! great] proportion ( surface expos$ to attack1 bo? favor *ange4 ,bo? ! area & ! mass ( sea-bottom s$im5t radically *ang$ 9 ?is way are l>ge1 b mo/ ( ! deposit does n correspond to any =mation kn[n on ! l&4 ,! r$ clay already ref]r$ to belongs to ?is class ( deposits4 ,its orig9 has be5 ! subject ( mu* discussion4 ,x conta9s mu* volcanic dbris1 v>i\s concretions1 bones ( mammals1 zeolitic cry/als1 & extra-t]re/rial sph]ules1 & d\btless ! insoluble products ( ! %ells ( pelagic life2 b x is /ill a moot$ "q h[ f> ! clay itself is ! product ( decompos$ %ells1 & h[ f> ! alt]$ product ( pulv]iz$ pumice1 volcanic a%1 du/1 etc4 ,pelagic life does n seem to be less abundant at ! surface :]e ! wat] is deep ?an :]e x is %all[1 & x w\ld appe> t ! %ells mu/ s9k 9 su* situations z else:]e4 ,if ! lime c>bonate ( globig]9a ooze be remov$ by dilute acid1 ! inorganic residue is simil> to ! r$ clay 9 ! ocean-bottom4 ,?is sugge/s t ow+ to ! m complete solution 9 ! v deep wat]1 ! lime c>bonate ( ! %ells has be5 dissolv$1 leav+ ! r$ clay z a residuum4 ,! m complete solution at ! bottom might be ! result ei!r ( ! great] pressure1 or ( a great] p]c5tage ( ,,co 9 ! wat] due to emanations f ! sea-floor1 or to bo?2 b ! sudd5ness ( ! transition f oozes to r$ clay1 ) increas+ dep?1 does n seem to be fully expla9$ by ^! assumptions4 ,! /udy ( ! dr$g+s has incl9$ ! /ud5ts ( ^! mat]ials to ! conclusion t volcanic mat]ials1 r ?an %ells1 are ! pr9cipal s\rce ( ! r$ clay4#ahb ,! volcanic mat]ials are ?\ght to h accumulat$ sl[ly & to h be5 long expos$ to ! action ( sea-wat]4 ,! v>i\s nodules & cry/als 9 ! clay are believ$ to be second>y products1 ! mat]ials = :i* 7 d]iv$ f ! decomposition ( ! same mat]ials4 ,eolian du/ may be a notable con/itu5t ( ! r$ clay4 ,v>i\s specific products ( *emical *ange may be briefly ref]r$ to4 ,! decomposition ( c]ta9 m9]al p>ticles1 su* z feldsp>1 gives rise to kaol91 & kaol9 is a v consid]able con/itu5t ( mo/ ( ! clayey deposits ( ! ocean-bottom4 ,! kaol9ization ( feldsp> may take place bo? on l& & 9 ! sea4 ,manganif]\s deposits are widespread 9 ! ocean-bottom1 occurr+ bo? z coat+s on gra9s ( me*anical s$im5ts1 %ells1 etc41 & z concretions rang+ 9 sizes f m9ute p>ticles to nodules an in* or m 9 diamet]4 ,! concretions are sometimes approximately sph]oidal1 b (t5 botryoidal4 ,^! manganif]\s nodules are believ$ to h aris5 f ! decay ( fragm5ts ( volcanic rocks4 ,9 _! decay1 ! manganese & iron are believ$ to h be5 fir/ *ang$ to c>bonates1 & subsequ5tly to oxides4 ,aft] manganese oxide1 iron oxide & silica are by f> ! mo/ abundant con/itu5ts1 b _m o!r sub/ances ent] into _! composition 9 m9or quantities4 ,ano!r sub/ance some:at widely di/ribut$ 9 ! sea-b$1 ?\gh by no means univ]sal1 is glauconite1 a complex silicate ( alum9a1 iron1 potassium1 etc4 ,glauconite is1 on ! :ole1 mo/ abundant along ! edges ( ! cont95tal %elves1 ?\gh x is by no means univ]sal 9 ?is position4 ,x is n commonly f\nd 9 deep wat]1 nor v ne> ! %ore1 b approximately at ! 8mud-l9e40 ,! glauconite gra9s beg9 to =m1 z a rule1 9 t9y %ells1 *iefly ! %ells ( =am9if]a4 ,aft] fill+ ! %ell1 ! %ell itself may disappe>1 :ile ! glauconite goes on accumulat+ ar\nd ! core already =m$1 until ! gra9 atta9s consid]able size4 ,glauconite is believ$ to be an alt]ation product ( c]ta9 sorts ( me*anical s$im5t1 ! *ange be+ effect$ "u ! influ5ce ( ! decay+ organic matt] 9 ! %ells4#ahc ,x does n occur :]e s$im5tation is rapid1 & its =mation appe>s to be favor$ by consid]able *anges ( temp]ature4 ,glauconite deposits occur on ! l& & are commonly kn[n z gre5 s& m>l4 ,glauconite also occurs sp>+ly 9 _m o!r s$im5t>y rocks4 ,illu/ration3 ,fig4 #ccj4--;,di/ribution ( v>i\s sorts ( deep-sea deposits4 7,murray4 ,*all5g] ,reports47 ,ano!r sub/ance :i* is some:at widespread 9 ! ocean-bottom is phosphate ( lime1 :i* occurs 9 v>i\s sorts ( oozes1 9 ! manganif]\s nodules1 9 glauconite1 & 9 indep5d5t nodules4 ,l ! gra9s ( glauconite1 ! gra9s ( phosphate ( lime appe> to h />t$ z concretions 9 %ells1 & to be ! result ( ! reaction ( organic matt] on ! cont5ts ( sea-wat]4 ,! imm$iate s\rce ( ! lime phosphate 9 ! wat] appe>s to h be5 ! %ells or bones ( ! num]\s animals liv+ 9 ! sea4 ,second>y m9]als made f ! con/itu5ts ( volcanic matt] :i* has be5 decompos$ occur n uncommonly 9 ! bottom ( ! sea4 ,^! m9]als belong to ! g5]al class ( zeolites1 phillipsite be+ ! mo/ abundant4 ,_! di/ribution is some:at wide1 b _! quantity is slight4 ,un=tunately1 k ( ! deep-sea deposits is limit$ to _! sup]ficial lay]s4 ,s\nd+s d n usually p5etrate m ?an a few in*es1 or at mo/ a foot or two4 ,unlike %all[-wat] deposits1 ^? ( ! really deep sea seem to f9d no correlatives 9 ! kn[n rock =mations ( ! l&4 ,,lakes4 ,mo/ ( ! ph5om5a ( ! ocean are repeat$ on a small] scale 9 lakes4 ,! waves ( lakes & _! att5dant und]t[s & littoral curr5ts are gov]n$ by ! same laws & d ! same sort ( "w z ! correspond+ movem5ts ( ! ocean4 ,tides are abs5t1 or insignificant1 b slight *anges ( level1 kn[n z sei*es1#ahd h be5 obs]v$ 9 _m lakes4 ,!y are probably caus$ by sudd5 *anges 9 atmosph]ic pressure4 ,:ile !y are g5]ally v slight1 !y frequ5tly am\nt to z mu* z a foot1 & occasionally to sev]al feet4 ,! sei*es are oscillatory movem5ts1 & _! p]iod is influ5c$ by ! l5g? & dep? ( ! lake4 ,!y h be5 /udi$ mo/ c>efully 9 ,switz]l&4 ,curr5ts correspond+ to ^? ( ! ocean are slight or want+ 9 lakes1 b s9ce mo/ lakes h inlets & outlets1 _! wat]s are 9 con/ant movem5t t[>d ! latt]4 ,9 mo/ cases ?is movem5t is too sl[ to be readily not$1 or to d effective "w ei!r 9 corrasion or transportation4 ,! "w ( ! ice1 on ! o!r h&1 is relatively m important 9 lakes ?an 9 ! sea4 ,*anges tak+ place 9 lakes4--,! processes 9 op]ation 9 lakes are easily obs]v$ & readily und]/ood4 7#a7 ,! waves we> ! %ores1 & ! mat]ial ?us d]iv$ is transport$1 assort$1 & deposit$ z 9 ! sea1 & all ! topographic =ms result+ f erosion or deposition along ! seacoa/ are reproduc$ on _! appropriate scale 9 lakes4 7#b7 ,/reams be> _! burd5 ( gravel1 s&1 & mud into lakes & leave x !re4 7#c7 ,! w9ds bl[ du/ & s& into ! lakes1 & 9 "s places pile ! s& up into dunes along ! %ores4 7#d7 ,animals ( v>i\s sorts live 9 ! lakes1 & _! %ells & bones give rise to deposits comp>able to ! animal deposits 9 ! sea4 7#e7 ,abundant plants gr[ 9 ! %all[ wat] ab\t ! bord]s ( _m ponds & lakes1 & z !y die1 _! sub/ance accumulates on ! bottom4 7#f7 ,at ! outlet ! wat] is con/antly l[]+ its *annel4 ,! l[]+ ( ! outlet is (t5 sl[1 especially if ! rock be coh]5t1 = ! outfl[+ wat] is usually cle>1 & !re=e ineffici5t 9 corrasive "w4 ,^! six processes are ess5tially univ]sal1 & all conspire aga9/ ! p]petuity ( ! lakes4 7#g7 ,9 lakes :]e ! temp]ature is l[ en\gh = ice to be =m$1 x cr[ds on ! %ores & develops ph5om5a peculi> to itself4 ,! ice ( ! sea may "w 9 simil> ways1 b its "w is re/rict$ to high latitudes4 7#h7 ,9 lakes 9 arid regions1 deposits are (t5 made by precipitation f solution4 ,! fir/ five & ! la/ ( ^! processes are fill+ ! bas9s ( ! lakes4 ,z ! s$im5t is deposit$1 a correspond+ volume ( wat] is displac$1 &1 if !re be outlets1 =c$ out ( ! bas9s2 ! six? process is equally antagoni/ic to ! lakes1 :ile ! sev5? has little influ5ce on _! p]man5ce4 ,giv5 "t en\gh1 ^! processes mu/ br+ ! hi/ory ( any lake to an end4 ,! l[]+ ( ! outlet w alone accompli% ?is result if ! bottom ( ! bas9 is above base-level4 ,_m lakes h already become ext9ct1 ei!r ?r\gh ! fill+ or dra9+ ( _! bas9s1 or ?r\gh bo? comb9$4 ,! antagonism ( riv]s & lakes long ago l$ to ! epigram 8,riv]s are ! mortal enemies ( lakes40 ,true z ?is /atem5t is1 x does n foll[ t lakes w ev] cease to exi/1 = ! causes :i* produce new lakes may be 9 op]ation contemporane\sly ) ^? :i* br+ lakes n[ 9 exi/5ce to an end4 ,lacu/r9e deposits4--,! b$s ( s$im5t deposit$ 9 lakes are simil> 9 k9d1 9 /ructure1 & 9 disposition to b$s ( s$im5t laid d[n 9 ! sea1 b riv]-borne s$im5t is m commonly conc5trat$ into deltas1 s9ce waves & %ore-curr5ts are less effective4 ,ev5 ! lime/one ( ! sea has its correlative 9 "s lakes4 ,"s ( x 0 made ( ! %ells ( fre%-wat] animals :i* ?rove :]e ! inwa% ( t]rig5\s s$im5t 0 slight1 "s ( x f ! calc>e\s secretions ( plants1#ahe & "s ( x 0 precipitat$ f solution4#ahf ,salt & iron-ore#ahg deposits are also sometimes made 9 lakes4 ,ext9ct lakes4--,! =m] exi/5ce ( lakes :]e none n[ exi/ may be kn[n 9 v>i\s ways4 ,if ! lake bas9 0 fill$1 its =m] area is a flat1 ! b$s ( :i* be> evid5ce1 9 _! composition1 _! /ructure1 & (t5 9 _! fossil cont5ts1 ( _! orig9 9 /&+ wat]4 ,su* a flat is commonly s situat$ topographically t ! bas9 w\ld be reproduc$ if ! lacu/r9e deposits 7 remov$4 ,to ?is g5]al rule !re might be exceptions1 z :]e a glaci] =m$ "o side ( ! bas9 :5 x 0 fill$4 ,if ! lake 0 de/roy$ by ! r$uction ( its outlet1 or by ! removal ( "s o!r b>ri]1 su* z glaci] ice1 or by desiccation1 %ore ph5om5a1 su* z bea*es1 spits1 etc41 may be f\nd4 ,9 "t su* evid5ces are de/roy$ by subarial erosion1 s t !y are mo/ di/9ct soon aft] ! lake becomes ext9ct4 ,_m lakes1 "s ( !m l>ge#ahh & _m ( !m small1 are kn[n to h become ext9ct1 :ile _m o!rs are n[ 9 _! la/ /ages1 namely1 m>%es4 ,_m o!rs h be5 greatly r$uc$ 9 size4 ,su* r$uctions are (t5 obvi\s :]e deltas are built into lakes4 ,?us ! delta built by ! ,rhone into ,lake ,g5eva is sev]al miles 9 l5g?1 & has be5 l5g!n$ ne>ly two miles s9ce ! "t ( ! ,roman occupation4 ,! end ( ,s5eca 7,n4 ,y47 lake has be5 cr[d$ nor?w>d "s two miles by deposition at its head4 ,simil> *anges h tak5 place & are n[ 9 progress 9 _m o!r lakes4 ,lake ice4#ahi--,s9ce fre% wat] is d5se/ at #ci ,fahr41 ice does n commonly =m on ! surface until ! temp]ature f top to bottom is r$uc$ to ?is po9t4 ,cool$ bel[ ?is temp]ature1 ! surface-wat] fails to s9k1 & ) suffici5t r$uction freezes4 ,if ! lake be small1 & especially if x be %all[1 x is likely to freeze ov] completely 9 any region :]e ! temp]ature is notably bel[ ! freez+-po9t = fre% wat] = any consid]able p]iod ( "t4 ,x is "u ^! circum/ances t ! ice becomes mo/ effective4 ,illu/ration3 ,fig4 #cca4--;,ice cr[d+ ^u l[ %ore4 ,cle> ,lake1 ,ia4 7,calv947 ,suppose a lake 9 temp]ate latitudes1 :]e ! range ( temp]ature is consid]able1 to be froz5 ov] :5 ! temp]ature is #bj ,fahr4 ,if n[ ! temp]ature be sudd5ly l[]$ to -#aj1 & su* *ange ( temp]ature is n uncommon 9 ! nor!rn "p ( ! ,unit$ ,/ates1 ! ice contracts notably4 ,9 contract+1 x ei!r pulls away f ! %ores or cracks4 ,if ! =m]1 ! wat] f :i* ! ice is )drawn quickly freezes2 if ! latt]1 wat] rises 9 ! cracks & freezes !re4 ,9 ei!r case1 ! ice-cov] ( ! lake is aga9 complete4 ,if ! temp]ature n[ rises to #bj ! ice exp&s4 ,! cov] is n[ too l>ge = ! lake1 & x mu/ ei!r cr[d up on ! %ores 7,fig4 #cca7 or ar* up 7wr9kle7 else:]e4 ,x foll[s ! "o c\rse or ! o!r1 or bo?1 accord+ to ! resi/ance (f]$ by ! %ore4 ,if ! wat] ne> ! %ore is v %all[1 ! ice freezes to ! s&1 gravel1 & b[ld]s at ! bottom4 ,if ! adjac5t l& is l[1 ! ice 9 exp&+ may %ove up ov] x1 c>ry+ ! dbris froz5 9 its bottom4 ,x may ev5 pu% up loose gravel & s& 9 front ( its edge if !y be pres5t on ! %ore4 ,:]e b[ld]s are froz5 to ! bottom ( ! ice1 ! %orew>d ?ru/ 9 exp&+ has ! effect ( %ift+ !m 9 ! same direction1 & ev5 ( lift+ !m a little above ! normal wat]-level4 ,?is con/ant process ( conc5trat+ b[ld]s at ! %ore-l9e gives rise to ! 8wall$0 lakes1 :i* are n uncommon 9 ! nor!rn "p ( ! ,unit$ ,/ates4 ,! 8wall0 does n commonly ext5d entirely ar\nd a lake1 ?\gh x exi/s at v>i\s po9ts on ! %ores ( _m lakes4 ,9 mak+ ! walls1 ! ice %ov$ up by w9ds1 especially 9 ! spr+ :5 ! ice is break+ up1 cop]ates4 ,illu/ration3 ,fig4 #ccc4--;,calc>e\s tufa domes4 ,pyramid ,lake1 ,nev4 7,russell47 ,if ! lake be bord]$ by a l[ m>%1 ! ice & froz5 e>? ( ! latt] are really cont9u\s ) ! ice ( ! lake1 & ! pu% ( ! latt] sometimes ar*es up ! =m] into di/9ct anticl9es1 ! froz5 "p only be+ involv$ 9 ! de=mation4 ,a succession ( cold] & less cold p]iods may give rise to a succession ( su* anticl9es4#aij ,if ! %ore be /eep & ( non-resi/ant mat]ial1 ! cr[d+ ( ! ice produces diff]5t b n less /rik+ results4 ,:]e ! ?ru/ ( ! ice is aga9/ a l[ cliff ( yield+ mat]ial1 su* z clay1 x di/urbs all above ! %ore-l9e4 ,:]e ! cliff is suffici5tly resi/ant1 x )/&s ! pu% ( ! ice1 & ! ice itself is w>p$ & brok54 ,sal9e lakes4--,a few lakes1 especially 9 arid or semi-arid regions1 are salt1 & o!rs are 8bitt]40 ,beside sodium *loride1 salt lakes usually conta9 magnesium *loride1 & magnesium & calcium sulphates4 8,bitt]0 lakes usually conta9 mu* sodium c>bonate1 z well z "s sodium *loride & sulphate1 & sometimes borax4 ,! degrees ( saltness & bitt]ness v>y f fre%ness on ! "o h& to saturation on ! o!r4 ,! wat] ( ! ,caspian ,sea 7lake7 conta9s1 on ! av]age1 less salt ?an t ( ! sea2 t ( ,great ,salt ,lake conta9s ab\t #ah2 t ( ! ,dead ,sea1 ab\t #bd2 & t ( ,lake ,van 7ea/]n ,turke/an71 ! d5se/ body ( wat] kn[n1 ab\t #cc4 ,see accompany+ table4 ,_m salt lakes1 su* z ! ,dead ,sea & ,great ,salt ,lake1 are desc5d$ f fre%-wat] ance/ors1 :ile o!rs1 l ! ,caspian & ,aral ,seas1 are probably isolat$ portions ( ! ocean4 ,lakes ( ! =m] class h usually become salt ?r\gh a decrease 9 ! humidity ( ! region :]e !y occur4 ,! wat] beg9s to be salt :5 ! aridity is su* t evaporation f ! lake exce$s its infl[4 ,9 ?is case ! infl[+ wat]s br+ 9 small am\nts ( sal9e & alkal9e matt]1 :i* is conc5trat$ z evaporation takes place4 ,! conc5tration may g on until ! po9t ( saturation is rea*$1 or until *emical reactions cause precipitation4 ,9 g5]al ! lea/ soluble m9]als are precipitat$ fir/4 ,?us gypsum beg9s to be deposit$ f sea-wat] :5 #cg ( x has be5 evaporat$2 b ! saturation-po9t = salt is n rea*$ until #ic ( ! wat] has be5 evaporat$ 7see p4 #cge74 ,! relations 9 lakes are simil>1 & gypsum deposits (t5 und]lie ^? ( salt4 ,deposits ( salt & o!r m9]al matt]s once 9 solution are mak+ 9 "s salt lakes at ! pres5t "t1 & consid]able =mations ( ! same sort h be5 s made 9 ! pa/4 ,buri$ b5ea? s$im5ts ( o!r sorts1 b$s ( common salt or ( o!r precipitates are pres]v$ = ages4 ,lime c>bonate has be5 precipitat$ 9 quantity f "s ext9ct lakes 7,fig4 #ccc74 ,! lakes :i* orig9ate by ! isolation ( portions ( ! sea are salt at ! outset4 ,if infl[ exce$s evaporation1 !y become fre%] & may ultimately become fre%2 o!rwise !y rema9 salt4 ,if evaporation exce$s infl[ !y dim9i% 9 size & _! wat]s become m & m salt or bitt]4 ,indirect effects ( lakes4--,lakes t5d to modify ! climate ( ! region :]e !y occur1 bo? by increas+ its humidity & by decreas+ its range ( temp]ature4 ,!y act z res]voirs = surface-wat]s1 & s t5d to re/ra9 floods & to promote regul>ity ( /ream fl[4 ,!y purify ! wat]s :i* ent] !m by all[+ _! s$im5ts to settle1 & s influ5ce ! "w & ! life ( ! wat]s bel[4 ,composition ( lake-wat]s4--,! accompany+ table#aia %[s ! composition ( v>i\s inclos$ lake-wat]s1 & gives "s idea ( ! wide range1 bo? 9 k9d & quantity1 ( ! m9]al matt] held 9 solution by !m4 ,x is to be not$ t ! table %[s ! composition ( ! wat]s ( exceptional1 r ?an common1 lakes4 ,! wat]s ( fre% lakes d n dep>t widely f ^? ( riv]s 7p4 #ajg74 ,,table--,,analyses ,,( ,,! ,,wat]s ,,( ,,inclos$ ,,lakes4 ,r$uc$ to ,p>ts p] #ajjj by ,dr4 ,h4 ,j4 ,van ,h\s54 ---------------------------------------- -------------------------------------- ,locality ,ab]t ,lake1 ,bogdo ,lake ,caspian ,sea4 #b;,caspian ,sea1 ,oregon ,w4 ,s4 ,w4 ( ne> m\? ,pis*9a1 at ( ! ,volga #ae feet dep?1 w9d1 ,w4 ,s4 ,w4 ,specific gravity #ajbc4ag ,date ,may #c1 #ahhc ,analy/ ,f4 ,w4 ,taylor ,gobel ,gobel ,h4 ,rose ,ref]5ce ,f\r? ,ann4 ,rep4,l>iet ,geological,bis*('s ,bis*('s ,u4 ,s4 ,geol4 ,exploration ( ,*emical ,*emical ,survey1 p4 #ded ,dead ,sea1 p4 ,geology1 ,vol4 ,geology1 #bhd ,i1 p4 #hi ,vol4 ,i1 p4 #hi ---------------------------------------- -------------------------------------- ,sodium1 ,na #b4hch #gd4gjj #a4dddj 4#cjha ,potassium1 ,k #aj4hhj #a4jda 4#jcih ,rubidium1 ,rb 444444 444444 444444 ,calcium1 ,ca 444444 #c4fdg 4#ahed 4#abch ,magnesium1 ,mg 4#jjb #ac4ggg 4#djie 4#jgbh ,li?ium1 ,li ,iron1 ,fe 444444 444444 444444 444444 ,*lor9e1 ,cl #h4daj #afc4cdd #b4gcgf 4#degf ,brom9e1 ,br 444444 4#jdc ,trace 444444 ,c>bonic acid gas1 ,,co #d4fec 444444 4#achb 4#cgdf ,sulphuric acid1 ,h,,s 4#eji 4#aih #a4ccgb 4#caji ,phosphoric acid1 ,,hpo ,nitric acid1 ,,no ,boracic acid1 ,h,,bo 444444 ,silica1 ,si,o 4#jfd ,alum9a1 ,al,o 444444 444444 444444 ,hydrog5 9 bic>bonates1 ,h 4#jjbc 4#jjfb ,ammonium1 ,,nh 444444 ,organic matt] 444444 444444 444444 444444 ---------------------------------------- ---------------------- #bg4ceg #bef4gej #f4bidj #a4fedj ---------------------------------------- -------------------------------------- ---------------------------------------- ---------------------------------------- ---------------- ,dead ,sea1 ,dead ,sea1 ne> ,dead ,sea1 at #cic ,dead ,sea1 at ,elton ,lake ,elton ,lake ,ras ,dale1 surface ! ,isl&1 ft41 betwe5 ,ras #fef ft41 betwe5 surface ,fes*kak & ,ras ,fes*kak ,ras ,z]ka & ,ras ,z]ka #a4jbaf #a4afdg #a4bbbe #a4bcjj ,m>4 #bj1 #ahfd ,apr4 #g1 #ahfd ,m>4 #ae1 #ahjd ,m>4 #ae1 #ahfd ,april ,augu/ ,t]reil ,t]reil ,t]reil ,t]reil ,gobel ,erdman ,l>tet ,geological,l>tet ,geological,l>tet ,geological,l>tet ,geological,bis*('s ,bis*('s ,exploration ( ,exploration ( ,exploration ( ,exploration ( ,*emical ,*emical ,dead ,sea1 p4 #bgh ,dead ,sea1 p4 #bgh ,dead ,sea1 p4 #bgh ,dead ,sea1 p4 #bgh ,geology4 ,vol4 ,geology1 ,vol4 ,i1 p4 #djc-dje ,i1 p4 #djc-dje ---------------------------------------- ---------------------------------------- ---------------- 4#hhe #bb4djj #be4jga #be4ajg #ea4eij #bi4cjj 4#dgd #c4edg #c4iij #d4ejc #a4afb 444444 444444 444444 444444 444444 #b4aej #i4jid #c4gjd #d4bah 444444 4#ajf #d4aig #be4ebi #da4cjf #db4jjf #bi4iga #de4eih 444444 444444 444444 444444 ,trace ,trace ,trace ,trace 444444 444444 #ag4fbh #abf4eba #aff4cdj #agj4dbe #aei4dih #aff4hij 4#afg #d4efh #d4hgj #d4che 4#jei 444444 ,trace ,trace ,trace ,trace 444444 4#bgb 4#bjb 4#did 4#dea 4#dei #ac4cbj #ag4gcd 444444 444444 444444 444444 4#jjf ,trace ,trace ,trace ,trace ,trace ,trace ,trace 444444 444444 444444 444444 ,truce ,trace ,trace ,trace 444444 444444 ,trace ,trace ,trace ,trace ,trace #e4jhj ---------------------------------------- ---------------------------------------- ---------------- #be4gji #aib4aec #bde4gcb #bea4ajc #bee4fjj #bfd4ihj ---------------------------------------- ---------------------------------------- ---------------- ---------------------------------------- ---------------------------------------- ------------------- ,elton ,lake ,great ,salt ,lake ,great ,salt ,lake ,great ,salt ,lake ,humboldt#aib ,lake ,indevak ,lake #a4bgbhh #a4agj #b4d #a4ajb #a4jjg 444444 ,octob] #ahej #ahfi ,aug41 #ahgc 444444 4444444 ,h4 ,rose ,l4 ,d4 ,gale ,o4 ,d4 ,all5 ,h4 ,bassett ,o4 ,d4 ,all5 ,gobel ,bis*('s ,/ambury's ,u4 ,s4 ,geological ,am]4 ,*emi/1 ,u4 ,s4 ,geol4 ,expl4,l>tet ,geol4 ,*emical ,exp$ition to ,expl4 #dj? p>4 #ahgd1 p4 #cie #dj? p>4 #ahgg1 ,expl4 ( ,geology4 ,vol4 ,great ,salt #ahgg1 ,vol4 ,,ii1 ,vol4 ,i1 p4 #ebh ,dead ,sea1 ,i1 p4 #djc-dje ,lake1 p4 #daj p4 #dce p4 #bhd ---------------------------------------- ---------------------------------------- ------------------- #ae4jfj #he4ccj #di4fij #ch4c 4#bghdb #id4jej #a4bjd #b4djg #i4i 4#jfjhc 4#ebi 444444 444444 444444 444444 444444 444444 ,trace#aif 4#bee 4#f 4#jabeg 4#abc #fj4edj 4#fcf #c4ghj #c4j 4#jafdh #e4jgf ,trace ,trace 444444 444444 444444 444444 444444 444444 #aga4icf #abd4ded #hc4idf #gc4f 4#biede #aeh4fhg ,trace 444444 444444 444444 444444 444444 4#bjabf 444444 #db4efj #ab4djj #i4heh #h4h 4#jcjdj #c4jfe 4#jjjfi 444444 444444 ,trace ,trace 444444 4#jcbej 444444 ,trace 444444 444444 444444 444444 44444 ---------------------------------------- ---------------------------------------- ------------------- #bia4cjj #bbb4hbj #adi4icf #acd4b 4#ibhjj #bfa4ecj ---------------------------------------- ---------------------------------------- ------------------- ---------------------------------------- ---------------------------------------- ------ ,soda ,lake1 ne> ,soda ,lake1 ne> ,mono ,lake1 ,cal41 ,urmiah ,lake ,ow5's ,lake1 ,cal4 ,ragt[n1 ,nev41 ,ragt[n1 ,nev41 at #a foot bel[ at #a foot bel[ at #ajj feet bel[ surface surface surface #a4aja #a4aja #a4jdh #a4aee #a4jea 444444 444444 ,july #af1 #ahhc 444444 444444 ,t4 ,m4 ,*at>d ,t4 ,m4 ,*at>d ,t4 ,m4 ,*at>d ,hit*cock ,o4 ,loew ,ante1 p4 #gj ,ante1 p4 #gj ,bullet9 ,no4 #i4 ,l>tet ,geological ,app5dix ,,jj ,ann4 ,u4,s4 ,geol4 ,survey1 ,exploration ( ,rep4 ,*ief p4 #bf ,dead ,sea1 p4 #bhd ,eng9e]s1 #ahgf p4 #aij ---------------------------------------- ---------------------------------------- ------ #da4fcb #dj4bjf #ah4ajj #gd4hij #ba4fej #b4bij #b4dbe #a4aaa #b4gea 444444 444444 444444 444444 444444 4#bgh 4#ebi ,trace 4#bde 4#bde 4#abe #b4iad ,trace 444444 ,trace 444444 444444 444444 444444 444444 #da4dif #dj4bjf #aa4faj #aai4dif #ac4ddj 444444 444444 444444 444444 #ae4fejg #ah4jehg #ad4dfeg 444444 #ac4adj #aa4gga #aa4idc #f4ebj #g4fga #i4cfb 444444 ,trace 444444 444444 444444 ,trace 4#bhe 4#bhg 4#aec ,trace 4#bge 4#bha 4#bfh 4#afd 444444 ,trace 444444 444444 444444 444444 444444 444444 ,trace ---------------------------------------- ---------------------------------------- ------ #aac4fdd #aac4fea #di4fcj #bje4ejj #fj4ejg ---------------------------------------- ---------------------------------------- ------ ---------------------------------------- ---------------------------------------- ---------------------- ,pyramid ,lake1#aic ,sevi] ,lake1 ,walk] ,lake1#aid ,w9nemucca ,van ,lake ,aral ,sea ,nev4 ,utah ,nev4 ,lake1 ,nev4 444444 444444 #a4jjc #a4jja ,aug4 #ahhb #ahgb ,sept41 #ahhb ,aug41 #ahhb ,f4 ,w4 ,cl>ke ,o4 ,loew ,f4 ,w4 ,cl>ke ,f4 ,w4 ,cl>ke ,*anc\rtois ,ante1 pp4 #eg ,u4 ,s4 ,survey1 ,w4 ,ante1 p4 #gj ,ante1 p4 #fc ,bis*('s ,*emical ,ro? ,*emical & #eh #ajj ,m41 ,vol4 ,,iii1 ,geology1 ,vol4 ,i1 ,geology1 p4 #dfe p4 #add p4 #id ---------------------------------------- ---------------------------------------- ---------------------- #a4agif #bh4hdj 4#heece #a4bigj #h4ejbd #b4deab 4#jgcc ,trace 4#jfhf 4#bdf 4#jehd 444444 444444 444444 444444 4#jjbb 4#jjhi 4#aah 4#jbbae 4#jaif 444444 4#deha 4#jgig #b4jjj 4#jchcj 4#jagc 4#aegd 4#eife 444444 44444 444444 444444 444444 44444 ,trace#aig 4#jjjh #a4dcjj #de4ejj 4#ehcge #a4ficd #e4fic #c4hchf 444444 444444 444444 444444 4#jjbi 4#dijjg 444444 4#dgddeg 4#cdehaih #e4bfgaie 4#jiah 4#ahbb #i4cde 4#ebjjj 4#accc #b4eee #c4ccfh 444444 4#jjaa ,trace 444444 444444 444444 444444 4#jccd 4#jjgej 4#jbge 4#ahj 4#jjcb 4444444 444444 444444 444444 ,trace ,trace ---------------------------------------- ---------------------------------------- ---------------------- #c4dhfa #hf4djc #b4ejaej #c4fjbe #bb4fjj #aj4hdaf ---------------------------------------- ---------------------------------------- ---------------------- ,,*apt] ,,vii4 ,,! ,,orig9 ,,& ,,desc5t ,,( ,,rocks4 ,x has be5 ! curr5t op9ion t ! e>? 0 once 9 a molt5 /ate1 & !nce cool$ to a solid condition1 & h5ce t all ! primitive rocks 7 igne\s4 ,ev5 ^? :o ?9k t ! e>? may nev] h pass$ ?r\gh a molt5 /ate agree t ! olde/ kn[n rocks are ei!r true igne\s rocks1 or rocks ( v simil> nature4 ,a molt5 magma may1 !re=e1 be tak5 z ! "m /ate ( ! rocks4 ,/>t+ ) ?is conception1 ! natural ord] ( ev5ts sugge/s ! inquiries 7#a7 h[ rocks are =m$ f molt5 magmas1 7#b7 :at natures !y assume1 7#c7 h[ o!r rocks are d]iv$ f !m1 7#d7 h[ /ill o!r rocks are d]iv$ f ^! d]ivatives1 & s on4 ,to answ] ^! inquiries is to trace out ! g5]ations ( rocks & le>n ! g5]al hi/ory ( rock-=mation4 7#a7 ,! process by :i* igne\s rocks are =m$ f lavas is actually tak+ place 9 exi/+ volcanoes4 ,z ^! are widely scatt]$ ov] ! face ( ! e>?1 ! mat]ial p\r$ out by !m repres5ts diff]5t p>ts ( ! int]ior & v>ies 9 nature accord+ly4 ,?is af=ds ! means ( /udy+ ! diff]5ces t arise f diff]5ces ( mat]ial4 ,?is is a radical consid]ation1 = v>iations 9 composition give rise to ! mo/ fundam5tal di/9ctions betwe5 rocks1 ?\gh by no means ! only ones4 ,rocks :i* h ! same composition (t5 diff] greatly 9 texture or /ructure1 ow+ to ! v>y+ conditions "u :i* !y 7 =m$4 ,9 ! solidification ( rocks f ! molt5 /ate1 ! rate ( cool+ causes _m diff]5ces4 ,a means ( /udy+ ?is is af=d$ by ! v>i\s lava fl[s t are n[ be+ p\r$ out on ! surface "u diff]5t conditions2 b a m important means is af=d$ by ext9ct volcanoes1 especially by ^? :i* h be5 deeply cut op5 by erosion4 ,9 c]ta9 v anci5t volcanoes1 n only h ! solidifi$ lava /reams ( ! surface be5 cut across by erosion1 b ! lava t rema9$ 9 ! crat]1 or 9 ! neck t l$ up f bel[1 is laid b>e = inspection4 ,exposures ( ev5 m pr(\nd nature h be5 made by ! great disruptions :i* ! out] "p ( ! cru/ has suff]$4 ,9 c]ta9 tracts !re h be5 pr(\nd fractures1 & ! =mations on "o side ( ^! h settl$ d[n & on ! o!r side h be5 pu%$ up 7fault$71 s z to expose p>ts t 7 once mu* bel[ ! surface4 ,sometimes also ! cru/ has be5 fold$ & crumpl$1 & ! wr9kles ?us =m$ h aft]w>ds be5 worn away or cut op5 by deep valleys1 & rocks t 7 once deeply buri$ h be5 laid b>e4 ,by ! revelations made 9 ^! & o!r ways1 x has be5 le>n$ t at v>i\s times 9 ! hi/ory ( ! e>? molt5 matt] has be5 ?ru/ into fissures or intrud$ betwe5 lay]s ( ! cru/ & cool$ !re1 )\t com+ to ! surface4 ,sometimes ! lava appe>s to h =c$ its way into ! rocks1 & sometimes to h lift$ ! upp] b$s & =m$ great subt]ranean lay]s or tumor-l aggregates1 call$ ba?yli?s & laccoli?s 7,fig4 #ccd74 ,su* intrud$ bodies ( molt5 rock1 solidify+ "u ! v>y+ conditions ( su* subt]ranean situations1 are a fruitful s\rce ( in/ruction respect+ ! influ5ce ( v>y+ rates & modes ( cool+1 z well z ( o!r att5dant conditions4 ,illu/ration3 ,fig4 #ccd4--;,diagram ( a laccoli?4 7,gilb]t47 ,x w ?us be readily se5 t ! rate ( cool+ ( ! v>i\s molt5 rocks mu/ h diff]$ v greatly4 ,9 ! portions p\r$ out ^u ! surface !re 7 sometimes n>r[ /reams & ?9 %eets1 giv+ l>ge exposure 9 proportion to ! mass 7,fig4 #cce71 & sometimes ?ick fl[s & deep pond+s 9 bas9s & *ok$ valleys1 giv+ massive bodies ) relatively small surface exposure4 ,!re 7 explosions ( ! lava into m9ute p>ticles ) almo/ in/antane\s cool+1 & !re 7 eruptions b5ea? ! sea ! peculi> effects ( :i* are r matt]s ( inf]5ce ?an ( positive k4 ,9 ! portions und]gr\nd !re 7 ins9uations into ?9 fissures1 on ! "o h&1 & 9-?ru/+s ( ?ick bodies1 on ! o!r4 ,"s intrusions ent]$ ! upp] "p ( ! cru/ :]e ! rocks 7 cold & wet1 & "s 7 ?ru/ into ! deep] portions :]e ! rocks 7 w>m] & less p5etrat$ by wat]4 ,sometimes ! lava rose rapidly & 0 little cool$ 9 passage1 sometimes sl[ly ) m cool+ en r\te1 & sometimes !re 7 long halts betwe5 eruptions1 ) mu* opportunity to cool4 ,an almo/ inf9ite v>iety ( conditions is ?us pres5t$1 & ) x a ri* field = ! /udy ( ! modes ( solidification4 ,illu/ration3 ,fig4 #cce4--;,fre% lava fl[1 ) l>ge surface exposure4 ,holemaumau1 ,hawaii4 7,libbey47 ,9 ! und]gr\nd intrusions ! additional factor ( high pressure 0 also pres5t1 & ?is is ! ?ird important condition 9 det]m9+ ! nature ( igne\s rocks4 ,! ?ree factors1 composition1 rate ( cool+1 & degree ( pressure1 require special consid]ation4 ,composition ( ,igne\s ,rocks4 ,all or ne>ly all ! *emical elem5ts kn[n on ! e>? are f\nd 9 great] or less am\nts 9 igne\s rocks1 & 9 a broad s5se are con/itu5ts ( !m4 ,if !re are any exceptions1 !y are mo/ likely to be f\nd 9 ! r>] elem5ts 9 ! atmosph]e4 ,oxyg51 nitrog51 hydrog51 aque\s vapor1 & c>bonic acid1 :i* make up ! mass ( ! pres5t atmosph]e1 are all f\nd 9 lavas & 9 _! cool$ products4 ,probably all ! r>] elem5ts also occur 9 igne\s rocks4 ,helium is kn[n to be giv5 =? by spr+s4 ,lead+ elem5ts4--,b al?\gh ne>ly or q all ! kn[n *emical elem5ts ent] into ! igne\s rocks1 only a few ( !m are abundant4 ,^! are reg>d$ z normal or ess5tial con/itu5ts1 :ile ! r>] sub/ances are reg>d$ z incid5tal4 ,by comb9+ a l>ge numb] ( ! mo/ tru/wor?y analyses ( rocks ( all sorts1 ,f4 ,w4 ,cl>ke#aii has e/imat$ ! relative am\nts ( ! m abundant elem5ts 9 ! cru/ ( ! e>? ) ! foll[+ result3 ,p]c5t4 9 ,elem5t4 ,symbol4 ! ,solid ,cru/4 ,oxyg5 7,o7 #dg4jb ,silicon 7,si7 #bh4jf ,alum9um 7,al7 #h4af ,iron 7,fe7 #d4fd ,calcium 7,ca7 #c4ej ,magnesium 7,mg7 #b4fb ,sodium 7,na7 #b4fc ,potassium 7,k7 #b4cb ,titanium 7,ti7 4#da ,hydrog5 7,h7 4#ag ,c>bon 7,c7 4#ab ,phosphorus 7,p7 4#ji ,manganese 7,mn7 4#jg ,sulphur 7,s7 4#jg ,b>ium 7,ba7 4#je ,/rontium 7,sr7 4#jb ,*romium 7,cr7 4#ja ,nickel 7,ni7 4#ja ,li?ium 7,li7 4#ja ,*lor9e 7,cl7 4#ja ,fluor9e 7,fl7 4#ja ------ #ajj4jj ,x w be se5 t only eight ( ! elem5ts hold a high rank 9 quantity4 ,_m t are ( ! utmo/ importance 9 ! hi/ory ( ! e>? & ! affairs ( m5 are l[ 9 ! li/1 or d n ev5 appe> 9 x at all1 because _! quantity is too small to be e/imat$ 9 p]c5tages4 ,! preci\s metals1 & ev5 "s ( ! m common metals1 z lead1 z9c1 & copp]1 are too sc>ce to =m an appreciable p]c5tage4 ,union ( elem5ts4--,9 a g5]al /udy ( ! igne\s rocks we may = ! pres5t neglect all b ! fir/ eight ( ^! elem5ts4 ,out ( ^! elem5ts spr+ v>i\s *emical comb9ations1 & out ( ^! comb9ations spr+ ! v>i\s m9]als1 & out ( ! comb9ations ( m9]als come ! v>i\s rocks4 ,! union ( oxyg5 ) ! o!r sev5 elem5ts may be tak5 z a fundam5tal /ep 9 ?is s]ies ( comb9ations4 ,! result is ! foll[+ oxides3 ,silica 7,si,o71 alum9a 7,al,o71 f]r\s1 f]ric1 & magnetic oxide 7,fe,o1 ,fe,o1 & ,fe,o71 magnesia 7,mg,o71 calcium oxide or lime 7,ca,o71 soda 7,na,o71 & pota% 7,k,o74 ,! oxyg5 sometimes unites 9 proportions diff]5t f ^? "h giv51 b su* exceptions may be neglect$ 9 a g5]al /udy4 ,we ?us h n9e lead+ oxides4 ,( ^!1 silica acts z an acid1 or m /rictly accord+ to ! new] *emical view1 z an acid anhydride4 ,all ! re/1 except ! magnetic oxide ( iron1 & sometimes ! oxide ( alum9um1 act z basic oxides4 ,9 ! old] *emical philosophy ^! oxides 7 suppos$ to comb9e by ! simple union ( an acid oxide ) a basic oxide1 & to rema9 z oxide jo9$ to oxide2 ?us silica 7,si,o7 & lime 7,ca,o7 =m$ silicate ( lime 7,ca,o1,si74 ,! symbols express ! idea bett] ?an ! words4 ,?is me?od is us$ 9 ! old] geological works & 9 "s ( ! lat]4 ,b 9 ! new] *emical doctr9e1 ! oxides are n believ$ to rema9 s di/9ct aft] _! union1 & ! symbols are writt5 ,ca,si,o1 & ! comp\nd is nam$ calcium silicate4 ,accord+ to ! mod]n doctr9e ( solution1 "s ( ! calcium1 silicon1 & oxyg5 may exi/ z free ions 9 molt5 rock4 ,! precise way 9 :i* ! elem5ts are relat$ to ea* o!r 9 ^! comp\nds c sc>cely be said to be kn[n4 ,= ! g5]al purposes ( geology x is mo/ conv5i5t to ?9k ( ^! oxides z unit+ 9 ! simple fa%ion fir/ nam$1 & ?is involves no app>5t geological error 9 g5]al /udies1 s9ce !y are oxides :5 !y ent] ! comp\nd1 & if ! comp\nd is decompos$ !y usually come =? aga9 z oxides2 b 9 clos] /udies m complex unions1 att5d$ by dissociations 7ionization71 mu/ be recogniz$4 ,=mation ( m9]als4--,z b "o ( ! lead+ oxides t ab\nd 9 an av]age magma plays ! "p ( an acid1 ! silica1 a v simple conception ( ! g5]al nature ( igne\s rocks may be rea*$ by not+ t !y are mo/ly silicates ( ! sev5 lead+ basic oxides--alum9a1 pota%1 soda1 lime1 magnesia1 & ! iron oxides4 ,?is g5]al idea is a v useful "o & repres5ts a mo/ important tru?2 b 9 its use we mu/ n =get t !re are _m exceptions4 ,sulphur1 phosphorus1 *lor9e1 & o!r elem5ts unite ) ! bases to =m sulphates1 sulphides1 phosphates1 phosphides1 *lorides1 etc4 ,s also !re are _m m9or bases t =m silicates2 & ^! m9or bases unite ) ! m9or acids to =m _m m or less r>e m9]als4 ,aga91 !re are native metals 9 "s igne\s rocks4 ,b altoge!r ^! h>dly rea* m ?an "o or two p]c5t4 ( ! :ole4 ,!re are1 h[ev]1 two exceptions ( m importance4 ,9 ! molt5 magma ! acid & basic elem5ts are n always ev5ly mat*$4 ,:5 !re is an excess ( silica1 a portion rema9s free & takes ! =m ( qu>tz 7,si,o74 ,if !re is an excess ( ! basic oxides1 ! weake/ "o is usually left out ( ! comb9ation4 ,?is is commonly ! iron oxide1 :i* !n usually takes ! =m ( magnetite 7,fe,o74 ,x is a s+ul> fact t qu>tz (t5 =ms :5 !re is no excess ( silica1 & magnetite :5 !re is no excess ( base4 ,qu>tz 7free acid anhydride7 & magnetite 7free basic oxide7 sometimes occur 9 ! same rock4 ,! explanation = ?is is yet to be f\nd4 ,^! =m r important exceptions to ! g5]alization t ! igne\s rocks are mo/ly made up ( silicates1 b1 ?us qualifi$1 x expresses ! ess5tial tru?1 & has ! m]it ( embody+ ! c5tral *emical fact relative to ^! rocks4 ,s\rces ( complexity4--,b "h simplicity ends4 ,z we pass on to ! specific silicates t are =m$1 we enc\nt] sev]al s\rces ( complexity4 ,9 ! fir/ place1 ! silica unites ) ! bases 9 diff]5t ratios & ?us gives rise to unisilicates or or?osilicates 7ratio ( oxyg5 ( bases to oxyg5 ( silica1 #a3a71 subsilicates 7ratio m ?an #a71 bisilicates 7ratio #a3b71 trisilicates or polysilicates 7ratio #a3c or high]71 & comb9ations ( ^!4 ,all ! bases are n kn[n to comb9e 9 all ^! ways1 b _m d 9 m ?an "o ( !m4 ,/ill1 if ! silica 7 cont5t to unite ) ea* ( ! bases by itself alone1 ! results w\ld rema9 comp>atively simple2 b in/ead ( ?is x unites ) two or m at ! same "t2 &1 m ?an t1 x unites ) !m 9 v>y+ am\nts4 ,! case w\ld /ill rema9 measurably simple if ^! *emical comp\nds always cry/alliz$ out by !mselves1 ea* comp\nd =m+ "o m9]al1 & b "o2 b ! diff]5t silicates h ! confus+ habit ( cry/alliz+ toge!r 9 ! same m9]al4 ,a cry/al may ?us sometimes be se51 "u ! microscope1 to be made up ( alt]nat+ lay]s ( diff]5t silicates2 e4g41 a microscopic lay] ( an alum9um-calcium silicate may be ov]la9 by a microscopic lay] ( an alum9um-sodium silicate1 & ! alt]nation may be repeat$ ?r\gh\t ! cry/al1 giv+ x a b&$ /ructure4 ,!re is reason to believe t ?is is true 9 _m cases :]e ! microscope fails to detect x1 & t less symmetrical comm+l+s ( silicates may take place4 ,z su* alt]nations or mixtures are n gov]n$ by any kn[n ma!matical law1 z is ! case 9 *emical comp\nds1 !re is no det]m9ate limit to ! numb] ( comb9ations t may arise4 ,z a matt] ( fact1 new ones are /ill be+ discov]$ 9 ! progress ( rese>*1 & ! total numb] t may ultimately be f\nd c sc>cely be prophesi$4 ,z a result ( all ?is f]tility ( comb9ation1 ! total numb] ( silici\s m9]als 9 igne\s rocks is l>ge4 ,x is ! function ( ! m9]alogi/ to treat ( ^! m9]als z su*4 ,! geologi/ deals ) !m z con/itu5ts ( ! e>? & z factors 9 its hi/ory4 ,only a few ( !m are s abundant z to require special individual notice 9 a g5]al /udy ( ! e>?4 ,x may be rem>k$ also t only a few ( !m c be id5tifi$ by simple inspection z !y occur 9 ! rocks1 p>tly because ( ! delicacy ( ! di/9ctions betwe5 _m ( !m1 & p>tly because ( _! m9ut5ess & intricate int]mixture4 ,! res\rces ( ! pol>iz+ microscope are necess>y = safe det]m9ation 9 mo/ cases4 ,! /ud5t ne$ n feel emb>rassm5t or disc\ragem5t if he is (t5 unable to recognize ! con/itu5ts ( ! intimately cry/all9e rocks4 ,_! det]m9ation has gr[n to be a pr(ession by itself4 ,! lead+ m9]als ( igne\s rocks4--,=tunately = ! simplicity ( geological /udy1 a few m9]als make up ! great mass ( ! igne\s rocks4 ,^! few are qu>tz1 ! feldspa?ic m9]als1 ! f]romagnesian m9]als1 & ! iron oxides4 ,qu>tz 7silica1 ,si,o7 is ! free acid already m5tion$4 ,! feldspa?ic & f]romagnesian m9]als are ! lead+ silicates ( ! e>?'s cru/1 & va/ly surpass all o!rs 9 abundance4 ,! feldspa?ic gr\p embraces m9]als =m$ by silica 9 union ) alum9a1 toge!r ) ei!r pota%1 soda1 or lime1 or two or m ( ^! toge!r4 ,! f]romagnesian gr\p embraces m9]als =m$ by ! union ( silica ) iron1 magnesia1 & lime1 toge!r ) m or less ( ! o!r basic oxides4 ,^! /atem5ts are only true 9 a v g5]al s5se4 ,admixtures1 replacem5ts1 & impurities are s frequ5t z to break d[n all %>p1 simple def9itions4 ,! feldspa?ic m9]als are normally light 9 color1 rang+ f :ite to r$ or gray4 ,! f]romagnesian m9]als are normally d>k 7commonly gre5i%7 f ! pres5ce ( iron1 ! great color+ elem5t ( rocks4 ,b ^! color di/9ctions d n hold good 9 detail & _c be mu* tru/$ z a means ( id5tification4 ,! feldspa?ic m9]als 7p4 #dfb7 embrace ! pota% feldsp>s1 or?oclase & microcl9e2 ! soda feldsp>1 albite2 ! lime feldsp>1 anor?ite2 & ! mix$ feldsp>s int]m$iate betwe5 albite & anor?ite1 viz41 ! soda-lime feldsp>1 oligoclase1 ! lime-soda feldsp>1 &es9e1 9 :i* lime & soda are ne>ly equal1 & ! lime-soda feldsp>1 labradorite1 9 :i* ! lime pr$om9ates2 toge!r ) leucite1 a pota% silicate high] 9 alkali ?an or?oclase1 & nephelite1 a soda silicate high] 9 soda ?an albite4 ,leucite & nephelite are usually classifi$ z feldspa?oids1 n z feldsp>s4 ,x is to be und]/ood t alum9a is normally pres5t 9 all ^!4 ,additional details respect+ ^! m9]als may be f\nd 9 ! ref]5ce li/1 p4 #dfj4 ,among ! f]romagnesian m9]als ! mo/ important are ! pyrox5es1 ! amphiboles1 & ! biotite type ( mica4 ,oliv9e is ( subord9ate importance4 ,! pyrox5es 7p4 #dfe7 & amphiboles 7p4 #dfj7 h ne>ly ! same *emical composition1 b diff] 9 cry/allization & physical prop]ties4 ,hornbl5de 7an amphibole7 has be5 melt$1 & on cool+ "u prop] conditions f\nd to take on ! =m ( augite 7a pyrox5e74 ,pyrox5e is sometimes alt]$ into uralite1 "o ( ! amphiboles4 ,! pyrox5es & amphiboles are ! mo/ abundant ( ! d>k m9]als 9 cry/all9e rocks4 ,! lead+ memb]s ( ! pyrox5e gr\p are augite1 diallage1 hyp]/h5e1 en/atite1 & soda pyrox5e4 ,! *ief memb]s ( ! amphibole gr\p are hornbl5de & ! soda amphiboles4 ,all are ess5tially silicates ( magnesia & iron oxide1 ) or )\t ! addition ( lime1 soda1 & alum9a4 ,details respect+ ^! may be f\nd 9 ! ref]5ce li/4 ,! two lead+ micas are ! iron-magnesia mica1 biotite1 & ! pota% mica1 muscovite1 ! famili> 8is+lass0 ( ! /ove-door4 ,*emically1 muscovite %\ld g ) ! pota% feldsp>s1 b x is di/+ui%$ f !m by its cry/all9e habit & physical prop]ties4 ,! biotite %\ld g *emically ) ! pyrox5es & amphiboles1 :i* x closely resembles except 9 its cry/all9e prop]ties4 ,details respect+ ! micas may be f\nd 9 ! ref]5ce li/1 p4 #dfd4 ,two iron oxides1 magnetite 7,fe,o7 & hematite 7,fe,o7 are widely dissem9at$ 9 igne\s rocks4 ,!y con/itute ! free bases already m5tion$4 ,summ>y ( sali5t facts4--,! sali5t facts are1 !re=e1 7#a7 t out ( ! sev5ty-odd *emical elem5ts 9 ! e>?1 eight =m ! *ief "p ( x2 7#b7 t "o ( ^! elem5ts unit+ ) ! re/ =ms n9e lead+ oxides2 7#c7 t "o ( ^! oxides acts z an acid & ! re/ z bases2 7#d7 t by _! comb9ation !y =m a s]ies ( silicates ( :i* a few are easily *ief2 7#e7 t ^! silicates cry/allize into a multitude ( m9]als ( :i* aga9 a few are *ief2 & 7#f7 t ^! m9]als are aggregat$ 9 v>i\s ways to =m rocks4 ,possess$ ( ^! lead+ ideas1 we are prep>$ to turn to ! consid]ation ( "s ( ! conditions "u :i* ^! comb9ations take place 9 ! =mation ( rocks f molt5 magmas4 ,,! ,,nature ,,( ,,molt5 ,,magmas4 ,we easily fall into ! habit ( ?9k+ ( molt5 rock z we ?9k ( a molt5 metal1 m]ely z a sub/ance :i* has pass$ f ! solid to ! liquid condition because ( high temp]ature4 ,) ! return ( l[ temp]ature a molt5 metal returns to ! solid /ate usually 9 ! same molecul> condition :i* x possess$ be=e4 ,! po9t ( fusion & ! po9t ( solidification are ! same & are rigidly fix$4 ,if ?is 7 true ( ! con/itu5ts ( a rock1 a def9ite ord] = ! solidification ( ! sev]al m9]als might be anticipat$4 ,z a matt] ( fact1 ! ord] is n ! same "u all conditions1 &1 :at is especially significant1 ! ord] is f> f be+ t 9 :i* ! con/itu5ts w\ld fuse or w\ld solidify sep>ately4 ,= in/ance1 9 a granite compos$ *iefly ( qu>tz1 feldsp>1 & mica1 ! qu>tz is (t5 ! la/ to take =m1 al?\gh x is m infusible ?an ! feldsp> or ! mica4 ,?is & o!r ph5om5a %[ t a molt5 magma is n to be view$ simply z a fus$ sub/ance1 b r z a solution ( "o silicate 9 ano!r1 or z a solution ( sev]al silicates 9 "o ano!r mutually4 ,! high temp]ature is to be reg>d$ m]ely z a condition pr]equisite to solution1 or z ! condition ( fusion ( "s "o con/itu5t :i* !n dissolves ! o!rs4 ,if cry/als ( sn[1 sug>1 & salt be mix$ at a l[ temp]ature & compact$1 ! mass may be reg>d$ z an artificial rock4 ,on rais+ ! temp]ature1 all w pass into solution :ile ! temp]ature is /ill some:at bel[ ! melt+-po9t ( ! sn[1 ! mo/ fusible1 & :ile x is mu* bel[ t ( ei!r ! sug> or ! salt4 ,?is p>ticul> case is in/ructive because ! ice is n simply fus$ by temp]ature2 ! aff9ity ( ! salt plays a "p4 ,if ! temp]ature 7 aga9 l[]$1 ! sug> & salt w\ld n cry/allize out at _! fus+-po9ts1 b w\ld rema9 9 solution d[n to & ev5 bel[ ! normal freez+-po9t ( wat]2 9 o!r words1 !y w\ld rema9 9 solution until ! wat] cry/alliz$ out & =c$ !m to take ! solid /ate4 ,?is holds good :5 ! am\nts ( ! sug> & salt are small relative to ! wat]4 ,if1 on ! contr>y1 _! quantity is l>ge relatively1 cry/allization w take place at high] temp]atures & be=e ! wat] cry/allizes to ice4 ,f ?is x appe>s t ! salt & sug> might cry/allize ei!r be=e ! wat] or aft] x1 accord+ to ! degree ( conc5tration4 ,! behavior ( mixtures ( m9]als 9 pass+ into & out ( ! molt5 condition appe>s to be q analog\s to ?is1 & h5ce a great v>iety ( results att5d ! process1 dep5d5t ^u ! numb]1 ! nature1 & ! relative quantities ( ! +r$i5ts4 ,! approv$ conception ( ! g5esis ( a rock f a molt5 magma 7:5 ample "t is giv57 is t "o comp\nd aft] ano!r cry/allizes out z ! temp]ature falls & its po9t ( saturation = ea* is rea*$1 until ! :ole has be5 solidifi$4 ,! modes ( comb9ation ( ! elem5ts 9 ! molt5 magma are n necess>ily ! same z ^? 9 ! d]ivative cry/als2 inde$1 ! comb9ations d\btless *ange z ! process proce$s2 c]ta9 con/itu5ts be+ tak5 out1 ! rema9+ ones probably re>range !mselves4 ,"t requir$ 9 cry/allization4--,! liquid magma ( igne\s rocks is ess5tially a fluid glass or slag4 ,x is analog\s to common glass1 :i* is a silicate ( pota%1 soda1 or o!r base1 except t usually common glass is relatively free f iron & o!r color+ sub/ances1 :ile ^! ab\nd 9 ! natural magmas & r5d] !m d>k & m or less opaque2 b ! fundam5tal nature is ! same1 except t ! natural lavas are usually mixtures ( sev]al silicates1 :ile ! artificial glasses consi/ ( only "o1 or at mo/ a few4 ,furnace slag is ess5tially an artificial lava4 ,:5 a lava is cool$ quickly1 ! comm+l$ silicates solidify 9 ! diffus$ condition ess5tially z !y 7 9 ! liquid2 = !re is no "t = ! silicate molecules ( a l k9d to come toge!r1 p>ticle by p>ticle1 9 regul> sy/ematic ord]1 z requir$ 9 cry/allization4 ,! ess5tial feature ( cry/allization is ?is sy/ematic arrangem5t ( ! molecules accord+ to a def9ite plan1 giv+ a specific cry/al =m1 z a cube1 a hexagonal prism1 etc4 ,!re are six 7sometimes made sev57 fundam5tal sy/ems ( cry/allization1 & a multitude ( v>iations ( special =m 9 ea* sy/em4 ,! treatm5t ( ^! =ms belongs to m9]alogy4 ,9 a ?ick viscid liquid1 ?is sy/ematic arrangem5t ( molecules into def9ite cry/al =ms takes place sl[ly1 = ! cry/all9e =ce 9 ! silicates is f> less en]getic ?an t 9 wat]1 :i* cry/allizes into ice ) mu* rapidity & ) great =ce4 ,because ( ?is sl[ness1 ! solidification ( ! lava may cat* ! process ( cry/allization at any /age4 ,if ! lava is cool$ quickly1 ! result is a glass2 if less quickly1 "p glass & "p cry/als2 if sl[ly en\gh1 all becomes cry/all9e4 ,9 g5]al ! sl[] ! gr[? ! l>g] ! cry/als4 ,! solidification product may1 !re=e1 range f a glass to a mass ( cry/als2 i4e41 x may be 7#a7 :olly glass1 7#b7 a glassy matrix ) a few small cry/als scatt]$ ?r\gh x1 7#c7 a less abundant glassy matrix ) m & l>g] cry/als1 7#d7 a m]e remnant ( glass 9 a mass ( cry/als1 or 7#e7 a mass ( cry/als ) no glass4 ,successive /ages ( cry/allization4--,s9ce eruptions take place int]mitt5tly1 x is obvi\s t cool+ ( ! lava may be 9 progress 9 its hidd5 res]voir dur+ ! quiesc5t int]vals betwe5 eruptions4 ,aft] a c]ta9 /age ( p>tial cry/allization has be5 rea*$ dur+ su* "t ( quiet1 a r5ewal ( eruption may take place & ! :ole mass ( lava be %ift$ into q new conditions1 & a second phase ( solidification may be sup]pos$ on ! "o already />t$4 ,! rock w !n %[ two phases ( cry/allization3 7#a7 l>ge cry/als ( ! k9d or k9ds mo/ prone to develop 9 ! giv5 lava may h gr[n dur+ ! fir/ long /age ( sl[ subt]ranean cool+1 :ile ! great] "p ( ! lava /ill rema9$ liquid2 & 7#b7 small cry/als or glass may h develop$ :5 ! m rapid cool+ "u ! new conditions took place4 ,! result w\ld be l>ge cry/als set 9 a matrix ( small cry/als or ( glass1 a comb9ation /yl$ porphyritic4 ,9 su* cases ! lava1 9 its lat] /ages1 c>ries ! l>ge cry/als float+ ?r\gh\t its mass1 & is n a simple liquid4 ,,! ,,fragm5tal ,,products ,,( ,,sudd5 ,,cool+4 ,pyrocla/ic rocks4--,! extreme example ( sudd5 cool+ is pres5t$ :5 lavas are viol5tly explod$ into ! air & solidify almo/ in/antly4 ,! result+ glassy p>ticles or filam5ts1 if small1 con/itute volcanic a%4 ,! explosion appe>s to be due to /eam & o!r gases :i* are held 9 ! deep] lava "u great pressure1 b :i*1 z !y rise t[>d ! surface ( ! lava :]e ! pressure is reliev$1 exp& ) explosive viol5ce4 ,x is probably also due 9 "p to progressive cry/allization1 :i* =ces ! gases out f ! "p t cry/allizes & ov]*>ges ! re/4 ,sometimes ! project$ p>ticles draw aft] !mselves long filam5ts l ! ?reads ( spun glass1 & sometimes :ile 9 ! air !y divide & draw ap>t1 sp9n+ a filam5t ( viscid lava betwe5 !m4 ,a v>iety ( ?is k9d at ! volcano ( ,kilauea 9 ,hawaii is kn[n z 8,pele's hair40 ,^! light filam5ts drift ) ! w9d & lodge on ! lee side ( ! volcano1 cov]+ ! surface 8l m[n grass0 7,dana74 ,illu/ration3 ,fig4 #ccf4--,volcanic bomb4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,:5 ! explod$ fragm5ts are co>s] !y fall ab\t ! volcanic v5t & =m ! tuffs 7tufa7 ( :i* mo/ /eep volcanic cones are *iefly built4 ,9 ^! l>g] fragm5ts1 cry/als are n infrequ5tly f\nd1 & ! same is ev5 true ( ! volcanic a%4 ,^! cry/als are und\bt$ly su* z _h already be5 =m$ 9 ! lava be=e x explod$1 & _! =mation1 z sugge/$ above1 may h contribut$ to ! explosion4 ,fragm5ts too l>ge to be borne f> away by ! air1 b /ill small1 are kn[n z lapilli1 especially if !y are some:at r\nd$ & gravel-l4 ,a f9] v>iety1 ( ! nature ( s&1 mu* us$ 9 mak+ ,portl& cem5t1 is locally kn[n z puzzolana4 ,illu/ration3 ,fig4 #ccg4--,volcanic bomb ( unusual =m1 #ac foot long4 ,c9d] ,buttes1 ,idaho4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,! r\gh]1 irregul> fragm5ts ( a cl9k]-l nature eject$ by volcanoes are kn[n z scori or c9d]s4 ,!y are m or less di/5d$ by gas-bubbles & are h5ce light & pumice\s4 ,! l>g] masses ( lava eject$ into ! air are (t5 caus$ to rotate by ! unequal =ce ( ! projection1 or by ! unequal friction ( ! air1 & to assume sph]oidal =ms1 ! int]nal gases at ! same "t (t5 exp&+ & r5d]+ ! mass vesicul>4 ,^! r\nd$ projectiles are kn[n z volcanic bombs 7,figs4 #ccf & #ccg74 ,balls ( lava t h orig9at$ 9 roll+ movem5ts ( ! see?+ mass1 or 9 o!r ways1 are also /yl$ bombs4 ,usage is n altoge!r h>moni\s or consi/5t 9 ! application ( ! t]m4 ,! l>g] masses t are project$ into ! air are m or less vesicul> f ! expansion ( includ$ gases1 z already not$1 & s ! fragm5tal products ( volcanic action grade into ! vesicul>4 ,! type ( ?is class is pumice1 9 :i* ! gas cavities make up by f> ! l>g] "p ( ! volume ( ! :ole mass1 & ! :ole is r$uc$ to ! condition ( a solidifi$ fro? or foam4 ,s ?9 are ! divid+ films ( glassy mat]ial 9 "s cases t ! :ole is pure :ite1 ?\gh ! same mat]ial 9 solid mass w\ld be d>k4 ,?is solidifi$ glassy fro? is (t5 light] ?an wat] & floats freely on ! sea until x becomes 8wat]-logg$0 & s9ks4 ,dr$g+s ( ! deep sea %[ t mu* pumice has accumulat$ !re1 & be+ f> f ! l& has escap$ burial by ! s$im5ts borne 9 by ! riv]s4 ,all ( ^! fragm5tal rocks produc$ by volcanic action are kn[n z pyrocla/ic 7fire-fragm5t$7 rocks1 a g5]al t]m ( mu* conv5i5ce 9 di/+ui%+ !m f lava-fl[s1 on ! "o h&1 & f ! fragm5tal rocks produc$ by air & wat] 7ord9>y cla/ics71 on ! o!r4 ,,! ,,glassy ,,rocks4 ,! solid glasses4--,! quick cool+ ( lava-fl[s into solid glasses is *iefly dep5d5t on _! exposure at ! surface4 ,h5ce x is (t5 ! case t ! ext]ior ( a lava-fl[ is glassy 9 great] or less] degree1 :ile ! int]ior is m or less cry/all9e4 ,quick cool+ is sometimes also due to ! intrusion ( ! lava 9 ?9 %eets into fissures 9 cold rocks4 ,:5 massive bodies ( lavas p5etrate solid rocks1 ! lava does n usually cool s fa/ z to prev5t "s degree ( cry/allization1 & ! cry/allization may ev5 become complete2 b if ! intrud$ lava %eet be v ?91 ! lava is liable to be cool$ to a ne>ly p]fect glass4 ,! glassy condition is1 !re=e1 subject to indef9ite gradations4 ,z a rule1 ! acid lavas are /iff] at ! same temp]ature ?an ! basic ones1 & cry/allize m sl[ly1 s t acid glasses are m common ?an basic ones4 ,! basic rocks usually cry/allize pretty ?or\ghly1 except on ! imm$iate surface ( ! fl[s4 ,! fir/ /ages ( cry/allization4--,! microscopic /udy ( ! volcanic glasses reveals great numb]s ( m9ute =ms kn[n z cry/allites1 microlites1 globulites1 etc41 t appe> to be fir/ /eps 9 cry/allization1 ?\gh _m ( !m d n take def9ite geometrical %apes & "s d n %[ ! optical *>act]s ( cry/als4 ,!re are m9ute globules 7globulites71 ne$les1 & hair-l bodies 7tri*ites7 ( m or less indet]m9ate nature1 toge!r ) o!r =ms t c be se5 to be c]ta9ly ! initial =ms ( well-kn[n m9]als4 ,illu/ration3 ,fig4 #cch4--;,fl[ /ructure 9 rhyolite4 ,ne>ly natural size4 7,photo4 by ,*ur*47 ,! obsidians4--,( ! compact glassy rocks1 obsidian is ! be/ type4 ,x is ess5tially a natural glass1 =m$ usually ( acid silicates4 ,x has ! close texture1 con*oidal fracture1 & o!r qualities ( glass4 ,x is usually black1 b sometimes r$1 br[n1 purple1 blui%1 or gray4 ,:ile *iefly ( glass1 x usually conta9s m or less ( ! incipi5t cry/als above describ$1 %[+ t ev5 "h ! fir/ /ep 9 ! gradation to ! next or ! cry/all9e /age has be5 tak54 ,^! incipi5t cry/als sometimes become s abundant z to *ange ! texture f ! vitre\s to ! /ony ord]4 ,9 "s cases1 ! /ony texture seems to h be5 develop$ 9 ! obsidian aft] x 0 =m$1 ! *ange be+ a "p ( a subsequ5t process ( devitrification1 b 9 o!r cases ! cry/als seem to be orig9al4 ,besides ^!1 !re are (t5 small globul> bodies kn[n z sph]ulites4 ,v>ieties ( glassy rock 9 :i* ! embryo cry/als are m num]\s & ! glassy texture less p]fect1 are kn[n z pit*/ones4 ,! fre% surfaces ( ^! h r ! aspect ( pit* or res9 ?an t ( true glass2 h5ce _! "n4 ,l ! obsidians1 !y are usually d>k1 b !y take on gre5i%1 br[ni%1 yell[i%1 & light-color$ hues z well4 ,sometimes glassy rock fractures 9 small sph]oidal =ms l pe>ls1 & is kn[n z p]lite4 ,basic glasses are relatively r>e1 & :ile usually includ$ "u ! t]m obsidian1 are sometimes giv5 special names4 ,illu/ration3 ,fig4 #cci4--;,fl[ /ructure 9 volcanic glass4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cdj4--;,fl[ /ructure 9 porphyry1 %[n by ! position ( ! l>ge cry/als4 ,ab\t two-?irds natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cda4--,scoriace\s texture4 ,ab\t f\r-fif?s natural size4 7,photo4 by ,*ur*47 ,,special ,,/ructures4 ,fl[ /ructure4--,lavas t cool into glassy rocks frequ5tly conta9 gas cavities1 color$ spots & v>iations ( texture :i*1 toge!r ) ! hair-l embryo cry/als1 are drawn out into l9es1 /reaks1 & p>allel belts by ! fl[ ( ! visc\s mass1 giv+ rise to rhyolitic or fl[ /ructure 7,figs4 #cch & #cci74 ,rocks 9 :i* ?is is ! mo/ pron\nc$ feature 7 =m]ly kn[n z rhyolites1 ?\gh ! t]m has drift$ away f ?is orig9al mean+ & has be5 appli$ to a class ( acidic rocks4 ,! obsidians & pit*/ones may be m or less rhyolitic "u ! microscope1 ?\gh to ! nak$ eye !y may appe> only z a glassy or res9\s mass4 ,! rhyolites g5]ally h b an imp]fect glassy texture1 s9ce ! cry/als & ! cavities sometimes make up a notable "p ( ! mass1 ! glassy portion be+ sc>cely m ?an a matrix 9 :i* ! cry/als1 sph]ulites1 & cavities are c>ri$4 ,by an increase ( ! cry/als 9 numb] & size1 ! rock passes by gradations into porphyry or phan]ite4 ,illu/ration3 ,fig4 #cdb4--,porphyritic texture4 ,two-?irds natural size4 7,photo4 by ,*ur*47 ,amygdaloids4--,9 lava-fl[s ! includ$ /eam (t5 collects 9 bubbles ne> ! surface z ! lava cools & =ms a vesicul> portion ) a scoriace\s texture 7,fig4 #cda74 ,9 its upp] "p1 ! vapor bubbles may be num]\s1 :ile bel[ !y become m & m scatt]$ until !y disappe>4 ,simil> bubbles are also (t5 f\nd ne> ! bottom ( a %eet ( lava4 ,?is is p]haps due to ! roll+ "u ( ! frontal surface ( ! lava-/ream z x fl[s4 ,lat]1 ^! cavities (t5 become fill$ ) m9]als deposit$ f solution & ! rock !n becomes an amygdaloid1 b ?is fill+ is a second>y action4 ,illu/ration3 ,fig4 #cdc4--,porphyritic texture4 ,natural size4 7,photo4 by ,*ur*47 ,,! ,,porphyritic ,,rocks4 ,:5 ! conditions are su* t aft] a "p ( ! magma has =m$ di/9ct cry/als float+ 9 ! rema9+ liquid lava1 !re is a *ange :i* causes ! re/ to solidify z a glass or z a mass ( small cry/als1 ! /ructure is kn[n z porphyritic1 & ! rocks possess+ x are call$ porphyries4 ,?is diff]5tiation into di/9ct cry/als set 9 a gr\nd-mass ( m9ute cry/als or ( glass (t5 gives a mottl$ or v>iegat$ aspect to ! rock1 especially if ! matrix ( glass or m9ute cry/als diff]s 9 color f ! di/9ct cry/als4 ,?is /ructure is mu* (t5] develop$ 9 acidic rocks ?an 9 basic ones1 because ! latt] cry/allize m readily4 ,! mo/ common porphyritic cry/als are feldsp> & qu>tz1 ?\gh !y are by no means ! only ones4 ,! matrix is also usually felsitic or qu>tzose1 b n necess>ily s4 ,! "* is a /ructural "o1 & is n dep5d5t ^u any special *emical or m9]alogical con/itution4 ,! di/9ct cry/als are kn[n z ph5ocry/s1 & ! v>ieties ( porphyries are nam$ f ! *>act]i/ic ph5ocry/1 e4g41 qu>tzophyre 7qu>tz-porphyry7 if ! conspicu\s cry/als are qu>tz1 or?ophyre if or?oclase1 augitophyre if augite1 etc4 ,a conv5i5t classification has rec5tly be5 propos$#bjj into 7#a7 leucophyre 7:ite porphyries71 :i* h a light-color$ gr\nd-mass set ) ph5ocry/s ( any k9d1 & 7#b7 melaphyres 7black porphyries71 :i* h a d>k-color$ gr\nd-mass1 ) ph5ocry/s ( any k9d4 ,:ile x is to be hop$ ?is usage w prevail1 x is to be not$ t ^! t]ms1 especially ! latt]1 h be5 us$ 9 a diff]5t s5se4 7,see ref]5ce li/ ( rocks1 p4 #dde47 ,9 _m cases ! gr\nd-mass itself becomes m9utely cry/all9e & ! porphyritic aspect is due simply to l>ge di/9ct cry/als set 9 a mass ( m9ute obscure ones4 ,! rock is !n really holocry/all9e1 b ! t]m porphyry is appli$ to x4 ,9 o!r rocks ! cry/als ( ! gr\nd-mass become m & m di/9ct1 ! porphyritic aspect gradually disappe>s1 & !re is a graduation into ! next class4 ,,! ,,phan]ocry/all9e ,,rocks4 ,! phan]ites4--,:5 "t en\gh is giv5 = ! cool+ process ! molt5 magma becomes completely cry/all9e4 ,! holocry/all9e rocks h5ce include a l>ge s]ies1 rang+ f ! mo/ acid to ! mo/ basic4 ,9 ?is class ! diff]5tiation ( ! rock mat]ial & ! =mation ( di/9ct m9]als rea* a high /age1 & z a natural result ! v>ieties ( rock are num]\s4 ,tak5 z a gr\p !y are phan]ites4 ,if !y are to be m p>ticul>ly *>act]iz$1 x is usually done on ! basis ( ! m9]als ( :i* !y are compos$4 ,! foll[+ are ! lead+ types1 beg9n+ ) ^? :i* are ri* 9 silica & poor 9 basic oxides1 & end+ ) ^? :i* are ri* 9 basic oxides & poor 9 silica4 ,illu/ration3 ,fig4 #cdd4--;,granitic texture4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,! granites4--,! t]m granite 0 orig9ally us$ to designate a granul>1 i4e41 a di/9ctly cry/all9e1 rock1 & x is /ill popul>ly & prop]ly s us$4 ,9 sci5tific treatises x has usually be5 conf9$ to a special aggregate ( cry/als ( qu>tz1 feldsp>1 & mica4 ,x has rec5tly be5 propos$ to give x aga9 a m g5]al application1 ?\gh n q its orig9al "o1 by includ+ "u x all holocry/all9e rocks compos$ ( dom9ant qu>tz & feldsp> ( any k9d1 ) mica1 hornbl5de1 or o!r m9]als 9 subord9ate am\nt4 ,9 sci5tific lit]ature z x n[ /&s1 granite consi/s ( qu>tz1 feldsp>1 & mica1 ! feldsp> be+ ( ! alkali-pota% or soda v>iety 7or?oclase1 microcl9e1 or albite71 & ! mica1 ei!r muscovite or biotite4 ,9 ! type =m ! cry/als are di/9ct & sometimes l>ge 7,fig4 #cdd74 ,!y are intimately m+l$ ) "o ano!r1 & 9 gr[+1 int]f]$ m or less ) ea* o!r & s became int]lock$4 ,! granites are among ! mo/ common & easily recogniz$ ( ! holocry/all9e rocks4 ,_! color is ma9ly dep5d5t ^u ! feldsp>1 ! r$ & p9k v>ieties ( ! m9]al giv+ rise to r$ granite1 & ! :ite v>ieties to gray granite4 ,illu/ration3 ,fig4 #cde4--;,graphic granitic 7or pegmatitic7 texture4 ,ne>ly natural size4 7,photo4 by ,*ur*47 ,v few granites con=m /rictly to ! type4 ,!y v>y by ! addition & sub/itution ( o!r m9]als1 & ^! sometimes become z prom95t z ! type m9]als4 ,! soda-lime feldsp>s sometimes take ! place ( ! or?oclase1 or accompany x2 hornbl5de & o!r m9]als take ! place ( ! biotite1 or occur ) x2 & s on4 ,:5ev] "o ( ^! replac+ or accessory m9]als is notable 9 quantity1 its "n is (t5 prefix$1 z hornbl5de-granite1 oligoclase-granite1 zircon-granite1 etc4 ,9 ?is way ! rock grades almo/ ins5sibly into ! sy5ites1 diorites1 etc4 ,v>iations also arise f ! abs5ce ( "o ( ! ?ree lead+ m9]als4 ,if mica is abs5t1 ! rock is t]m$ an aplite 7qu>tz & feldsp>74 ,if ! feldsp> is abs5t1 x is call$ a greis5 7qu>tz & mica74 ,if qu>tz is abs5t1 x is t]m$ a m9ette 7feldsp> & mica74 ,^! v>ietal t]ms are nei!r univ]sally nor always consi/5tly us$1 & x is to be hop$ !y w be replac$ by ! sy/ematic nom5clature rec5tly propos$ & outl9$ lat] 7p4 #dea74 ,! granites 7 =m$ f a magma ri* 9 silica1 alum9a1 pota%1 & soda1 b g5]ally poor 9 lime1 iron1 & magnesia4 ,incid5tally o!r sub/ances 7 pres5t4 ,! alum9a1 pota%1 & o!r bases unit$ ) s mu* ( ! silica z 0 requir$ to =m ! feldsp>s & micas1 & ! rema9+ silica cry/alliz$ into qu>tz4 ,granite is normally a massive rock )\t foliation or b&+4 ,if x takes on ^! *>act]s1 x becomes a gneiss1 & passes into ! foliat$ or s*i/ose class ( rocks1 to be discuss$ lat]4 ,! texture ( graphic granite 7see pegmatite7 is notably peculi>1 due to ! simultane\s cry/allization ( ! qu>tz & feldsp> 7,fig4 #cde74 ,! sy5ites4--,:5 ! mica ( a granite is replac$ by hornbl5de1 ! rock is n[ commonly kn[n z a hornbl5de-granite1 b x 0 =m]ly call$ sy5ite1 because f\nd at ,sy5e on ! ,nile4 ,! t]m sy5ite is n[ appli$ to a rock consi/+ ess5tially ( feldsp> & hornbl5de or mica1 b !re is a complete gradation f ! granites to ! sy5ites4 ,! magma ( ! sy5ites 0 ri*] 9 iron & magnesium ?an ! typical granitic magma4 ,! sy5ites also grade into o!r classes1 z d ! granites1 & are nam$ by simil> prefixes1 z augite-sy5ite1 etc41 & "s ( ^! v>ieties h special names4 ,! sy5ites are r$ or gray1 accord+ to ! color ( ! feldsp>1 & are usually d>k] ?an ! granites4 ,! texture ( sy5ite is l t ( granite4 ,9 ! s*eme ( field names rec5tly propos$1 sy5ite is made to include all holocry/all9e rocks compos$ ma9ly ( feldsp> ( any k9d1 ) subord9ate am\nts ( mica1 hornbl5de1 pyrox5e1 & o!r m9]als1 b )\t a noticeable am\nt ( qu>tz4 ,! diorites4--,^! embrace rocks :i* 7 cry/alliz$ f a magma /ill poor] 9 silica & ! alkalies1 & ri*] 9 ! e>?y bases4 ,9 composition !y closely approa* ! ideal av]age rock1 b usually fall a little bel[ x 9 silica & ! alkalies1 & rise a little above x 9 ! e>?y bases4 ,9 curr5t usage1 diorite is def9$ z an intimate mixture ( cry/als ( hornbl5de & a plagioclase feldsp>4 ,x diff]s f ! sy5ite 9 hav+ plagioclase feldsp> in/ead ( or?oclase4 ,by sub/itutions & ! addition ( accessory m9]als1 ! diorites graduate t[>d ! granites & sy5ites on ! "o h&1 z already not$1 & into gabbros on ! o!r4 ,9 ! s*eme rec5tly propos$1 all holocry/all9e rocks 9 :i* hornbl5de is dom9ant & feldsp> subord9ate are class$ z diorites4 ,! gabbros4--,! "n gabbro 0 =m]ly appli$ to a co>se-gra9$ basic rock consi/+ ( labradorite & diallage1 b ! "n has be5 gradually ext5d$ until x embraces a l>ge gr\p ( rocks t h ess5tially ! same composition z ! dol]ites m5tion$ bel[1 b are co>s] 9 cry/allization1 & ! cry/als d n embrace "o ano!r 7i4e41 are n ophitic74 ,! pr9cipal m9]als are plagioclase 7normally labradorite7 & pyrox5e 7normally diallage7 ) magnetite or ilm5ite4 ,!y are usually d>k1 heavy rocks4 ,! pe>ly lu/] ( ! cleavage faces ( ! diallage1 :5 pres5t1 gives a peculi> %e5 to a fre% surface ( ! rock4 ,9 ! rec5tly propos$ field names1 gabbro is made to include all phan]ocry/all9e rocks 9 :i* pyrox5e pr$om9ates1 att5d$ by feldsp> ( any k9d 9 subord9ate quantity1 ) or )\t hornbl5de or mica4 ,! p]idotites4--,^! /& at ! basic end ( ! s]ies1 hav+ be5 =m$ f a magma 9 :i* ! silica 0 l[ 7#ci-de p] c5t471 z 7 also ! alum9a1 lime1 & alkalies1 b 9 :i* ! magnesia 0 relatively v high1 rang+ f #ce to #dh p] c5t4 ,! rock consi/s v l>gely ( oliv9e associat$ ) pyrox5e1 magnetite1 & o!r v basic m9]als4 ,little or no feldsp> is pres5t4 ,! p]idotites are mu* less abundant ?an ! prec$+ classes & repres5t a v di/9ctive phase ( ! magma 9 :i* ! magnesia 0 greatly conc5trat$4 ,closely alli$ to ! p]idotites are rocks :i* are made up l>gely ( a s+le basic m9]al1 z augitite1 pyrox5ite1 hornbl5dite1 rocks ess5tially =m$ ( ! m9]als augite1 pyrox5e1 & hornbl5de respectively4 ,x w be not$ t 9 ^! rocks ! magma became q simple 9 nature1 j z at ! acid end ( ! s]ies c]ta9 rocks become comp>atively simple f ! conc5tration ( ! acid elem5t1 z 9 c]ta9 acidic granites1 felsites1 etc4 7,see pp4 #ebc-ebd47 ,! basalts4--,! t]m basalt is us$ 9 a some:at compreh5sive way to embrace d>k1 compact1 igne\s rocks t appe> to be ne>ly homog5e\s1 ow+ to ! m9ut5ess ( ! cry/als1 :i* are usually s small z to be id5tifiable only "u ! microscope4 ,9 "s cases ! cry/als are scatt]$ ?r\gh\t a gr\nd-mass aft] ! porphyritic fa%ion4 ,9 "s ( ^! cases !re is a true glassy base1 & 9 su* cases ! rock does n /rictly belong 9 ! holocry/all9e gr\p4 ,9 ! m typical cases ! con/itu5t m9]als are v m9utely cry/alliz$ & intimately int]mix$4 ,! lead+ m9]als are plagioclase 7usually labradorite or anor?ite7 & pyrox5e 7usually augite71 ) oliv9e & magnetite or ilm5ite usually pres5t4 ,!re is a consid]able range 9 *emical nature1 b ! basalts are relatively poor 9 silica1 usually also l[ 9 pota% & soda1 b ri* 9 lime1 magnesia1 & ! iron oxides4 ,!y are class$ z basic & are sometimes highly s4 ,! magmas ( ! basalts are especially fluid1 & :5 p\r$ =? ^u ! surface easily spread out 9 ?9 %eets4 ,9 cool+ !y are prone to take on a column> or basaltic /ructure1 ! columns /&+ at "r angles to ! surfaces expos$ to cool+4 ,! columns are sometimes curv$1 ow+ to ! peculi> attitude ( ! cool+ surface4 ,! columns ( ,giant's ,causeway & ,f+al's ,cave are famili> examples4 ,! dol]ites4--,! basalts graduate ins5sibly into ! dol]ites2 inde$ ! dol]ites may be reg>d$ simply z basalts ( co>s] cry/allization4 ,! m9]als are evid5t to ! eye & range up to m$ium size4 ,! m abundant m9]als are plagioclase feldsp> 7labradorite or anor?ite71 ) "o or m ( ! f]romagnesian m9]als 7augite1 oliv9e1 or biotite71 & magnetite or ilm5ite4 ,9 ! gr[? ( ! m9]als "o cry/al frequ5tly embraces o!rs1 giv+ an ophitic /ructure4 ,! dol]ites h _m v>ieties1 due ei!r to accessory m9]als or to ! developm5t ( "s ( ! con/itu5ts m amply ?an ! re/4 ,! type may be said to consi/ ( plagioclase & augite1 ! o!r m9]als be+ reg>d$ z accessories4 ,magnetite or ilm5ite is almo/ univ]sally pres5t4 ,! v>ieties are usually designat$ by prefixes1 z oliv9e-dol]ite1 en/atite-dol]ite1 etc41 b special names are also us$ = "s ( ^!4 ,illu/ration3 ,fig4 #cdf4--;,conglom]ate1 ,c>bonif]\s s]ies4 ,bancr(t ,place1 ,newport1 ,r4 ,i4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,! anci5t dol]ites h usually und]gone int]nal *anges & su* rocks are (t5 call$ diabases4 ,:ile ! use ( ! t]m has n be5 uni=m1 x accords ) ! bett] practice to reg>d ! diabases simply z p>tially alt]$ dol]ites & basalts4 ,9 g5]al1 !re=e1 ! diabases are b anci5t dol]ites4 ,g5]al names4 ,! difficulty ( di/+ui%+ _m ( ! =ego+ rocks f ea* o!r by any means available 9 ! field1 ow+ to ! m9ut5ess ( ! cry/als1 & to ! gradation ( "o type ( rock into ano!r1 makes x desirable to employ c]ta9 g5]al names :i* w correctly express ! lead+ "* ( ! rock )\t imply+ a k ( ! precise m9]al composition4 ,a conv5i5t t]m ( ?is k9d is gre5/one1 :i* m]ely indicates t ! f]romagnesian m9]als are prom95t & usually give a gre5i% or d>k ca/ to ! rock4 ,! gre5/ones embrace ! diorites1 dol]ites1 "s ( ! gabbros & ! basalts1 & may ev5 ext5d to ! p]idotites & "s ( ! m hornbl5dic ( ! granitoid rocks4 ,ano!r conv5i5t "n is trap1 :i* may be us$ = any d>k1 heavy igne\s rock4 ,! "n 7f trappe1 /airs7 ref]s to ! /ep-l arrangem5t :i* ! edges ( ! sup]impos$ %eets ( lava (t5 take1 especially :5 ! lava is ( ! free-fl[+1 basaltic k9d4 ,illu/ration3 ,fig4 #cdg4--;,brecciat$ lime/one1 ,calcif]\s =mation4 ,"o mile s\? ( ,highgate ,falls1 ,vt4 ,! t]m basalt is sometimes us$ to embrace any ( ! v f9e-gra9$ d>k igne\s rocks4 ,9 su* cases1 x cov]s ! v f9e-gra9$ dol]ites1 diorites1 p]idotites1 etc4 ,! t]m granite 0 us$ orig9ally = any co>se-gra9$ cry/all9e rock1 & !re is a t5d5cy to revive ?is e>ly use4 ,9 g5]al descriptions1 "s ( our be/ petrograph]s call any co>sely cry/all9e rock 7e4g41 co>se-gra9$ sy5ites1 diorites1 gabbros1 etc47 granite4 ,! t]m granitoids may be us$ ) /rict propriety to cov] all rocks ( ?is class4 ,,d]ivation ,,( ,,second>y ,,rocks4 ,rocks1 ?\gh commonly made ! symbol ( ! abid+1 are subject to con/ant sl[ *anges4 ,?r\gh ^! *anges new] rocks h be5 d]iv$ f old] ones1 & /ill o!rs 9 turn f ^! d]ivatives1 & s on 9 an endless *a94 ,all d]iv$ rocks are conv5i5tly t]m$ second>y1 ?\gh !y may be sev]al g5]ations remov$ f ! primitive rocks1 & ev5 ! primitive rocks1 z we n[ und]/& !m1 may be !mselves d]iv$4 ,! ord9>y *anges ( rock are mo/ active at or ne> ! surface1 & ! processes ( su* *ange h already be5 discuss$ 9 "p "u ! titles 8,wea!r+0 7pp4 #ed & #aaj71 8,erosion0 7pp4 #aai-abc & #cdb-cdi71 8,transportation0 7pp4 #aae-aai & #ced-cee71 & 8,deposition0 7pp4 #agg-bjd & #cee-cfc74 ,illu/ration3 ,fig4 #cdh4--,qu>tzitic breccia4 ,ab\t "o-?ird natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cdi4--,section ( lime/one %[+ abundant fossils imb$d$ 9 a matrix made up ( comm9ut$ %ell matt]4 ,ab\t two-?irds natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cej4--,lime/one compos$ *iefly ( %ells4 ,ab\t ?ree-f\r?s natural size4 7,photo4 by ,*ur*47 ,regoli?4--,! fir/ great product ( ! surface *anges is mantle-rock 7regoli?71 :i* compreh5ds all ! loose matt] t spr+s f rock decay1 we>1 fracture1 & o!r =ms ( dis9tegration4 ,x lies 9 an unconsolidat$ %eet on ! face ( ! l&1 :e!r z soil1 s&1 clay1 e>?1 gravel1 or loose rock4 ,disrupt$ products3 arkose & wacke4--,9 dry regions1 9 cold regions1 on m\nta9 heights & precipit\s slopes1 & "u o!r conditions :]e sudd5 *anges ( temp]ature & fro/ action "w effici5tly1 rocks are brok5 d[n into f9e fragm5ts )\t mu* *emical decomposition4 ,su* disaggregat$ r ?an decompos$ matt]1 if d]iv$ f granitic & simil> cry/all9e rocks1 is t]m$ arkose1 or arkose s&1 & consi/s ( fragm5ts ( qu>tz1 feldsp>1 mica1 etc4 ,common s& consi/s ess5tially ( qu>tz gra9s4 ,if ! f9e fragm5ts are d]iv$ f ! d>k] igne\s rocks1 & consi/ ma9ly ( gra9s ( plagioclase feldsp>1 & f]romagnesian m9]als1 x is sometimes call$ wacke4 ,?is t]m is n widely us$ 9 j ?is s5se1 b !re seems to be an important place = x1 & x w be s employ$ 9 ?is "w4 ,^! disaggregat$ s&s are b special phases ( ! mantle-rock4 ,dis9tegrat$ products4--,:5 ! surface-rock is *emically decompos$1 ! residual mat]ial is conf9$ ma9ly to ! insoluble portions1 i4e41 ! silici\s & clayey p>ts2 :ile ! lime1 magnesia1 soda1 pota%1 & simil> sub/ances are l>gely dissolv$ & borne to ! ocean4 ,! pota% is some:at m dispos$ to rema9 ) ! clays ?an ! soda1 lime1 or magnesia2 b residues ( all are usually pres5t4 ,classes ( ,s$im5t>y ,rocks4 ,%ales1 s&/ones1 & conglom]ates4--,z already %[n 9 ! discussion ( ! atmosph]e & surface-wat]s1 ! mantle-rock is con/antly be+ borne away & r$eposit$ 9 lodgm5t spots on ! l& or 9 ! bas9s ( ! sea1 :ile x is con/antly be+ r5ew$ bel[4 ,x is an evanesc5t b ev]-r5ew$ d]ivative mantle4 ,9 ?is process ( r5ewal1 removal1 & r$eposition1 ! mantle mat]ial is usually assort$ into mud1 s&1 & gravel2 & ^! sev]al classes ( mat]ial are laid d[n m or less sep>ately1 & usually take ! /ratifi$ =m1 because _! deposition dep5ds on diff]5t degrees ( motion ( ! transport+ wat]s or w9d4 ,:5 ^! sev]al classes ( mat]ial become cem5t$ or o!rwise h>d5$1 !y give rise to %ales 7cem5t$ muds71 s&/ones 7cem5t$ s&s71 & conglom]ates 7or pudd+-/ones1 cem5t$ gravel1 ,fig4 #cdf74 ,if ! co>se mat]ial rema9s angul>1 !y =m breccia in/ead ( conglom]ates 7,figs4 #cdg & #cdh74 ,= ! mo/ "p1 ! deposits ( mud1 s&1 & gravel are made "u ! sea or 9 lakes & e/u>ies1 b !y are also =m$ on ! l& 9 lodgm5t bas9s1 9 l[-gradi5t valleys1 & on base-pla9s4 ,! deposits ( s$im5t on l& h receiv$ less recognition ?an !y des]ve4 ,:5 =m$ "u ! sea or 9 o!r life-su/a9+ wat]s1 %ells & o!r organic mat]ial are liable to be entrapp$ & to =m a "p ( ! rock4 ,^! organic rema9s1 or fossils1 greatly aid 9 int]pret+ ! deposits 9 :i* !y occur4 ,fossils are less liable to be pres]v$ 9 s$im5t>y deposits =m$ on l&4 ,!re is1 !re=e1 "s gr\nd to suspect t great s]ies ( s&/ones & %ales :i* d n conta9 m>9e or fre%-wat] fossils 7 =m$ 9 lodgm5t bas9s on l&1 ?\gh ! abs5ce ( fossils _c be reg>d$ z pro( ( su* orig94 ,illu/ration3 ,fig4 #cea4--;,globig]9a ooze4 ,magnifi$ #bj times4 7,murray & ,r5>d47 ,illu/ration3 ,fig4 #ceb4--,pt]opod ooze4 ,magnifi$ #d times4 7,murray & ,r5>d47 ,lime/ones & dolomites4--,( ! lime1 magnesia1 soda1 & pota% lea*$ out ( ! surface-rocks & c>ri$ to ! ocean 9 solution1 ! lime is l>gely extract$ to =m ! %ells1 skeletons1 tee?1 armor1 & o!r h>d p>ts ( sea-animals & sea-plants4 ,^! limy p>ts are at l5g? left on ! floor ( ! ocean & become m or less dis9tegrat$ & help to =m b$s ( lime-mud & lime-s& :i* 9 "t are cem5t$ into lime/one 7,figs4 #cdi1 #cej1 #cea1 & #ceb74 ,a l>g] proportion ( ! magnesia rema9s 9 solution 9 ! sea-wat]1 b 9 ways n yet well und]/ood1 ! magnesia sometimes unites ) ! lime to =m dolomite1 a d\ble c>bonate ( lime & magnesia 7,ca1,mg7,,co4 ,?is *ange is sometimes local1 & sometimes affects great s]ies ( b$s1 m commonly ! anci5t ones ?an ! mod]n4 ,sometimes ! dolomization appe>s to h tak5 place long aft] ! orig9al lime/one 0 =m$ & probably sometimes aft] x 0 lift$ out ( ! sea1 :ile 9 o!r cases x seems to h tak5 place :ile ! s$im5t 0 accumulat+1 or at lea/ be=e ! next ov]ly+ b$s 7 laid d[n4 ,! pota% 9 solution is to "s l>ge ext5t tak5 up by ! l&- & sea-plants or is reta9$ 9 ! clays1 & ?r\gh !m becomes aga9 incorporat$ 9 ! s$im5ts4 ,! soda l>gely rema9s 9 solution 9 ! sea-wat]4 ,precipitates4--,:5 a portion ( ! ocean-wat] is isolat$ 9 a region :]e evaporation f ! surface ( ! wat] is great] ?an ! ra9fall on x1 & ! infl[ f ! tribut>y bas91 ! lime1 magnesia1 soda1 pota%1 & o!r dissolv$ sub/ances 7solutes7 are conc5trat$ until ! wat] becomes saturat$4 ,! solutes are !n precipitat$ 9 ! ord] 9 :i* !y rea* ! po9t ( saturation4 ,?is ord]1 :5 tak5 9 /rict & full detail1 gives a v complex s]ies1 b ! lead+ deposits are calcium c>bonate 7lime/one71 calcium sulphate 7gypsum71 & sodium *loride 7halite or rock salt7 7see p4 #cge74 ,isolat$ lakes 9 arid regions may give rise to simil> deposits4 ,x has sometimes be5 ?\ght t ! anci5t lime/ones 7 produc$ l>gely by precipitation f conc5trat$ sea-wat]4 ,:ile ?is is probably ! case 9 "s in/ances & to "s degree1 x has n be5 demon/rat$ t ! great lime/one =mations 7 made to any l>ge ext5t 9 ?is way4 ,! m accept$ view is t ! lime/ones 9 ! ma9 7 made f organic rema9s4 ,! lime 9 solution 9 ! ocean is *iefly 9 ! =m ( ! sulphate4 ,illu/ration3 ,fig4 #cec4--;,diatom ooze4 ,magnifi$ #aej times4 7,murray47 ,iron ,ore-b$s4--,9 a some:at diff]5t way iron ore-deposits are =m$ by ! precipitation ( iron oxide or iron c>bonate f solutions ( f]r\s comp\nds4 ,! f]r\s comp\nds 9 solution 7 lea*$ f iron-be>+ rocks by p]colat+ wat]s4 ,! mo/ famili> case is t ( iron-be>+ spr+s4 ,on exposure to ! air1 ! iron comp\nds 9 solution und]go *ange1 & f]ric oxide is ?r[n d[n1 usually =m+ limonite 7,fe,o1#c;,h,o71 b sometimes hematite 7,fe,o74 ,?is *ange is common 9 m>%es & gives orig9 to 8bog-ore40 ,simil> deposits take place 9 c]ta9 %all[ lakes1 & h5ce are kn[n z 8lake ore40 ,iron ore sometimes also =ms at ! bottom ( a peaty b$ or 9 muddy soil4 ,9 connection ) ! great coal =mations1 b$s ( iron c>bonate 7sid]ite7 occur4 ,organic matt] seems to play a great "p bo? 9 ! orig9al solution & ! lat] deposition ( ^! ores4 ,f c]ta9 soils & clay-b$s on :i* ! anci5t coal-produc+ =e/s grew1 ! iron has be5 almo/ completely remov$1 ei!r by ! action ( ! roots1 or m probably by organic acids aris+ f _! decay & f ! decay+ vegetation on ! surface4 ,on fl[+ into %all[ bodies ( wat] or into m>%es1 ! wat]s conta9+ su* dissolv$ iron comp\nds usually ?r[ d[n _! iron cont5t ei!r z a c>bonate 7sid]ite71 or z a hydr\s f]ric oxide 7limonite74 ,! sid]ite is =m$ :]e decay+ vegetation is pres5t to furni% abundant c>bon dioxide & to p>tially protect ! iron solution f oxidation1 & ! limonite :]e free oxidation takes place4 ,s&1 silt1 clay1 or calcium c>bonate (t5 accumulates ) ! iron precipitate1 & ! result is an impure deposit :i* becomes an iron/one4 ,su* deposits (t5 become segregat$ into nodules1 z w be expla9$ lat]4 ,x is ?\ght t diatoms sometimes aid 9 ! deposit ( iron ore 9 %all[ wat]s4 ,silici\s deposits4--,9 ! decomposition ( igne\s rocks1 a c]ta9 portion ( ! silica1 z well z ( ! bases1 is dissolv$ & c>ri$ away 9 solution4 ,c]ta9 organisms extract ?is f solution = _! skeletons1 j z o!rs extract calcium c>bonate4 ,! accumulation ( ^! silici\s skeletons (t5 =ms silici\s rocks4 ,! diatom1 radiol>ian1 & o!r oozes 7,fig4 #cec7 ( ! deep sea are ! great examples4 ,sometimes lay]s ( infusorial e>?1 tripolite1 arise f ! %ells ( diatoms & o!r aquatic organisms secret+ silica4 ,! wat]s 9 :i* su* e>?s accumulate are r %all[1 & ei!r fre% or salt4 ,! mo/ famili> examples ( indurat$ rocks =m$ 9 ?is g5]al me?od are ! fl9ts & *]ts 7impure fl9ts7 t occur 9 lime/one & *alk1 *iefly z nodules1 b sometimes 9 di/9ct b$s4 ,organic rocks4--,:ile mo/ lime/ones1 *alks1 fl9ts1 *]ts1 & ! silici\s & calc>e\s oozes are =m$ ?r\gh ! ag5cy ( organisms1 !y are n !mselves /rictly organic4 ,!re is1 h[ev]1 a small b important gr\p ( rocks =m$ directly f organic matt]4 ,9 favorable situations ! woody p>ts ( plants1 fall+ into wat]1 are s f> pres]v$ f decay t !y accumulate 9 b$s1 & by sl[ *anges pass into peat1 lignite1 bitum9\s coal1 an?racite1 & graphite4 ,! fir/ ( ^! is compos$ ess5tially ( c>bohydrates & hydroc>bons mu* z plants are1 :ile ! la/ two are ma9ly c>bon1 & ! int]m$iate memb]s repres5t /ages ( passage f ! fir/ to ! la/4 ,!y are all d]iv$ f ! /rictly organic "p ( ! plants1 & spr+ ess5tially f ! atmosph]e & hydrosph]e4 ,!y are only indirectly associat$ ) ! evolutions ( ! inorganic s]ies4 ,,int]nal ,,alt]ations ,,( ,,rocks4 ,besides ! extreme alt]ations ( rocks at ! surface ( ! e>? by :i* !y pass into solution & into residual mantle-rock1 & at l5g? by transportation & re-s$im5tation become /ratifi$ rocks1 z j describ$1 ^? rocks :i* are n at ! surface are subject to *anges t give rise to sev]al v>ieties ( alt]$ rocks4 ,^! *anges are tak+ place con/antly "u ord9>y conditions1 ?\gh usually v sl[ly4 ,"u great pressure & heat ! *anges are relatively rapid & int5se1 & lead to results n rea*$ "u o!r conditions4 ,^! m pr(\nd *anges are t]m$ metamorphism1 & w be consid]$ lat]4 ,x is1 h[ev]1 important to recognize ! great fact t ! out] "p ( ! e>?1 = p]haps #bj1jjj or #cj1jjj feet1 is m or less fractur$ & p]meat$ by wat] conta9+ 9 solution v>i\s sub/ances dissolv$ f ! atmosph]e1 ! soil1 & ! rocks ?r\gh :i* x has already pass$1 & t ?is p]meat+ & circulat+ wat] is n[1 & = long ages has be51 work+ *anges 9 ! rocks1 p>tly by dissolv+ matt] out ( !m1 p>tly by deposit+ matt] 9 !m1 & p>tly by furni%+ a m$ium ?r\gh :i* new comb9ations ( _! con/itu5ts may take place4 ,?is out] fractur$ portion ( ! li?osph]e has be5 call$ ! zone ( fracture4#bja ,oxidation & deoxidation4--,at & above ! surface ( ! und]gr\nd wat]1 :]e ! rocks are easily rea*$ by atmosph]ic wat]s c>ry+ mu* free oxyg51 & by ! air itself1 oxidation prevails4 ,?r\gh oxidation ! f]r\s oxides are *ang$ to f]ric oxides1 a *ange :i* is usually manife/$ by a transition f a gray1 gre51 or blue color1 to buff1 br[n1 yell[1 or r$4 ,! p>tial progress ( su* oxidation is (t5 %[n 9 a fractur$ block or b[ld] ^: ext]ior %[s ! latt] colors1 :ile ! int]ior %[s ! =m]4 ,! sulphides1 ( :i* common pyrites 7,fe,s7 is ! mo/ famili>1 are oxidiz$ into sulphates1 & !n sometimes pass on into ! high] oxides & o!r comp\nds4 ,?us copp]as 7,fe,s,o7 arises f pyrites 7,fe,s7 by direct oxidation ( bo? ,fe & ,s4 ,! sulphuric acid ( ?is comp\nd1 unit+ ) "s base /rong] ?an ! f]r\s oxide1 gives rise to fur!r oxidation & results 9 hematite 7,fe,o7 & limonite 7,fe,o1#c;,h,o74 ,9 g5]al1 ! m9]al con/itu5ts ( ! rocks 9 ?is upp] zone take on _! maximum /ates ( oxidation4 ,?is oxidation affects m or less pr(\ndly ! "* ( ! rock z a :ole4 ,deep] 9 ! e>? oxidation is less preval5t1 & ! action is sometimes rev]s$ & deoxidation takes place4 ,s also :]ev] organic matt] is und]go+ decomposition deoxidation is likely to occur4 ,solution & deposition4--,solution prepond]ates 9 ! upp] "p ( ! zone ( fracture1 b deposition is preval5t 9 its deep] p>ts4 ,! calcium c>bonate & silica dissolv$ ne> ! surface are (t5 deposit$ bel[ z calcite & qu>tz4 ,! sulphates & o!r sulphur comp\nds t are =m$ & dissolv$ ne> ! surface are apt to be *ang$ into sulphides l[] d[n by deoxidation4 ,! soluble oxides & o!r comp\nds =m$ ne> ! surface are (t5 likewise precipitat$ bel[4 ,?is is p>ticul>ly true :]e ! desc5d+ wat]s enc\nt] decompos+ organic matt]1 & :]e !y m+le ) wat]s t h foll[$ o!r r\tes & h become *>g$ ) diff]5t solutes4 ,on com+ toge!r1 reaction betwe5 ! con/itu5ts takes place1 result+ sometimes 9 new solutions & sometimes 9 precipitation4 ,if ^! l[] deposits ( calcite1 qu>tz1 sulphides1 etc41 are made 9 ! pores ( ! rock1 !y *ange its texture & composition4 ,if !y are made 9 fissures !y con/itute ve9s1 & if a suffici5t p]c5tage ( ! ve9 matt] consi/s ( valuable metallic comp\nds1 !y con/itute ores4 ,z ! wat]s desc5d !y suff] great] & great] pressure & "s increase ( temp]ature1 & ^! *anges modify _! p[] to hold sub/ances 9 solution4 ,9 g5]al1 ! wat]s increase 9 solv5t p[]1 b ! effect is diff]5t = diff]5t m9]al sub/ances1 & h5ce z a rule ! wat]s are tak+ up "s sub/ances & lay+ d[n o!rs z !y proce$4 ,aft] p5etrat+ to great] or less dep?s1 ! wat]s may come aga9 to ! surface1 ei!r because !y are pu%$ up by ! high] head ( ! wat]s beh9d1 or because !y become w>m] & ?us light]1 & are =c$ up by ! heavi] cold wat]s above1 or else !y pass up by diffusion ?r\gh ! desc5d+ wat]s4 ,9 any case1 ! deep1 w>m wat]s1 usually r highly *>g$ ) mat]ial dissolv$ 9 _! previ\s c\rses1 are apt to deposit "s ( _! burd5 z !y asc5d to horizons ( l[] pressures & temp]atures4 ,!y are p>ticul>ly liable to make deposits :]e !y comm+le ) o!r wat]s diff]5tly *>g$ ) solutes4 ,?us int]nal *anges 9 ! body ( ! rocks are1 & = ages h be51 tak+ place4 ,9 ! upp] "p ( ! deposit+ zone1 calcite is ! dom9ant m9]al deposit$1 :ile 9 ! l[]1 qu>tz is m common2 b mu* dep5ds on local conditions & o!r influ5ces1 & no rigid rule holds good4 ,hydration & dehydration4--,wat] sometimes unites directly ) "s ( ! con/itu5ts ( a rock & produces hydrat$ m9]als1 i4e41 m9]als t h wat] z an elem5t ( _! con/itution1 n simply wat] absorb$ into _! pores4 ,a l>ge class ( m9]als kn[n z zeolites1 because !y swell up & und]go life-l contortions :5 _! basic wat] is driv5 (f by heat1 are examples ( hydr\s products4 ,a m famili> example is limonite 7,fe,o1#c;,h,o71 ( :i* yell[ o*] is a v>iety1 :i* on heat+ suffici5tly gives (f its wat] & becomes hematite 7,fe,o7 or r$ o*]4 ,! turn+ ( yell[ clay to r$ brick on burn+ is a famili> example ( dehydration4 ,! g5]al t5d5cy 9 ! upp] zones p5etrat$ by wat] is t[>d hydration4 ,9 ! l[] zones1 :]e ! pressure is great1 ,van ,hise holds t !re is a t5d5cy t[>d dehydration1 if ! rocks h be5 previ\sly hydrat$4 ,?is may be ! case if rocks h once be5 ne> ! surface & lat] deeply buri$ by ! accumulation ( s$im5ts on !m4 ,if ! pr9ciple holds1 rocks subject$ to int5se lat]al pressure may be dehydrat$4 ,c>bonation & dec>bonation4--,! igne\s rocks are l>gely silicates4 ,! c>bonic acid ( ! surface-wat]s & ( ! air act+ ^u !m1 conv]ts !m1 9 "p1 into c>bonates4 ,9 ?is way has aris5 mo/ ( ! orig9al supply ( calcium & magnesium c>bonates4 ,orig9al c>bonates =m$ 9 ?is way are precipitat$ & r$issolv$ aga9 & aga94 ,! c>bonates 9 riv]-wat]s are mu* m l>gely solutions ( previ\sly solid c>bonates ?an orig9al c>bonates =m$ f ! silicates4 ,! potassium & sodium ( ! silicates also =m c>bonates1 b by pref]5ce !y unite ) ! sulphur & *lor9e1 & h5ce appe> m l>gely z sulphates & *lorides4 ,c>bonation is usually accompani$ by oxidation & hydration4 ,^! sev]al processes break up ! complex & relatively un/able silicates into simpl] & m /able silicates1 c>bonates1 & oxides4 ,?is is illu/rat$ by ! foll[+ =mulas illu/rative ( ! *anges und]gone by augite & labradorite1 two common rock-=m+ m9]als4 ,! composition ( augite may be repres5t$ by ! =mula ,ca,o47,mg1,fe7,o4#b,si,o 7,mg1,fe7,o47,al1,fe7,o4,si,o4 ,assum+ ,mg & ,fe to be equal 9 am\nt 9 ! fir/ half ( ! above =mula1 & ,mg & ,fe to be equal 9 ! fir/ "p ( ! second half1 & ,al & ,fe to be equal 9 ! la/ "p ( ! second half1 d\bl+ ! :ole & all[+ x to be act$ on by ,,co & ,h,o1 we h #b;,ca,o4#b,mg,o4#b;,fe,o4,al,o4,fe,o4#f ,si,o #f;,,co #b;,h,o #b;,ca,c,o #b,mg,c,o #b;,h,o4,al,o4#b,si,o #b;,fe,c,o ,fe,o #d,si,o4 ,! hydr\s silicate ( ! la/ "p ( ! equation is kaol94 ,! composition ( labradorite is repres5t$ by ! =mula ,ca,o4,al,o4#b,si,o ,na,o4,al,o4#f,si,o4 ,assum+ ! two molecules repres5t$ by ?is =mula to be equally abundant1 & all[+ ! :ole to be act$ on by ,h,o & ,,co1 we h ,ca,o4,na,o4#b;,al,o4#h,si,o #d;,h,o #b;,,co ,ca,c,o ,na,,co #b7b;,h,o4,al,o4#b,si,o7 #d,si,o4 ,:5 wat]s *>g$ ) c>bonates desc5d into ! e>? !y are likely to precipitate a portion ( _! burd51 =m+ calcite & o!r cry/all9e c>bonates1 & h5ce ^! are among ! mo/ common m9]als f\nd 9 ve9s & rock cavities4 ,c>bonates are also deposit$ :5 c>bonate-*>g$ wat]s come to ! surface & evaporate or lose a "p ( _! c>bon dioxide4 ,dec>bonation also takes place1 b x is1 at lea/ at ! surface1 a mu* less common process1 & its conditions are less well und]/ood4 ,suffici5tly high heat w drive (f ! c>bon dioxide1 z 9 ! artificial process ( burn+ lime1 b ?is is r>ely obs]v$ 9 nature4 ,ev5 lava intrusions d n usually r$uce lime/one to cau/ic lime at any appreciable di/ance f ! contact4 ,x is believ$1 h[ev]1 t 9 ! deep] zones1 :]e high pressure & heat prevail1 c>bonates are *ang$ into silicates1 ?us 9 a way rev]s+ ! process t prevails at ! surface1 & sett+ free aga9 a portion ( ! c>bon dioxide t _h become lock$ up 9 ! =mation ( ! c>bonates4 ,to ?is action "s ( ! c>bon dioxide ( deep-seat$ !rmal spr+s is assign$4 ,! c>bonation ( ! silicates takes place at ! exp5se ( ! c>bon dioxide ( ! atmosph]e & hydrosph]e1 & h5ce 9 proportion z ! igne\s rocks are *ang$ into c>bonates1 ! atmosph]e & hydrosph]e are deplet$ ( c>bon dioxide1 new supplies be+ neglect$4 ,z plants are dep5d5t on c>bon dioxide = _! pr9cipal food1 & z animals are dep5d5t on plants = _! food1 directly or indirectly1 ! process ( c>bonation has a pr(\nd be>+ on ! life-hi/ory ( ! e>?1 & w (t5 invite att5tion 9 ! hi/orical *apt]s4 ,x is suffici5t "h to note t c>bonation is "o ( ! *ief processes 9 ! alt]ation ( igne\s rocks & furni%es1 directly & indirectly1 a l>g] p]c5tage ( ! m9]al sub/ances dissolv$ 9 ! wat]s t fl[ f ! l&1 ?an any o!r s+le process4 ,molecul> re>rangem5ts4--,besides ^! & simil> *anges t involve additions & subtractions ?r\gh ! ag5cy ( p]colat+ wat]1 ! molecules ( "s ( ! rock con/itu5ts re>range !mselves1 or ! elem5ts ent] into new *emical relations2 ?us1 pyrox5e may pass into hornbl5de by a *ange ( ! cry/all9e arrangem5t ( ! molecules4 ,! *ange may sometimes be caught 9 progress1 ! out] "p ( ! cry/al be+ hornbl5de 7:i* :5 ?us =m$ is call$ uralite71 :ile ! he>t ( ! cry/al rema9s pyrox5e4 ,s aragonite may pass into calcite4 ,by *anges ( ! =ego+ k9ds1 _m cry/all9e rocks are mu* alt]$4 ,"s become *loritic f ! developm5t ( ! s(t1 gre5 hydrat$ m9]al1 *lorite1 d]iv$ f ! pyrox5e1 amphibole1 biotite1 & p]haps o!r silicates ( ! orig9al rock4 ,o!rs become talcose f ! developm5t ( talc1 a v s(t1 unctu\s1 hydr\s magnesian silicate develop$ f ! magnesian m9]als ( ! orig9al rock4 ,soap/one or /eatite is a rock compos$ ess5tially ( su* second>y mat]ial4 ,s]p5t9e is a rock made up ( a simil> second>y m9]al 7s]p5t9e7 app>5tly d]iv$ f *rysolite 7oliv9e7 & o!r magnesian m9]als4 ,epidote1 a complex lime-iron-alum9a silicate1 (t5 recognizable by its peculi> pi/a*io-gre5 color1 is d]iv$ f o!r silicates1 & is r common 9 _m v>ieties ( cry/all9e rocks4 ,melaphyre is a "n appli$ r loosely & v>i\sly to c]ta9 alt]$ basic rocks ( ! basalt family4 ,diabase is ess5tially an alt]$ dol]ite4 ,ne>ly all ! v anci5t basaltic rocks %[ notable degrees ( alt]ation1 ev5 ?\gh !y appe> to h escap$ unusual dynamic conditions s9ce _! orig9al =mation1 & h5ce _! alt]ation seems to h result$ *iefly f ! op]ation ( unobtrusive ag5cies1 *ief among :i* is ! circulation ( wat]4 ,! ,sali5t ,features ( ,rock ,desc5t4 ,! =ego+ processes by :i* primitive or igne\s rocks are dis9tegrat$ & _! con/itu5ts conv]t$ into fragm5tal mat]ial may be said to con/itute ! desc5t ( rocks 9 its full] s5se4 ,view$ *emically1 ! great features ( ! process are 7#a7 ! break+ d[n ( ! complex silicates1 & 7#b7 ! ga!r+ ( ! resultant simpl] silicates 7ma9ly alum9um silicates7 into ! silt & clay b$s1 7#c7 ! assembl+ ( a l>ge "p ( ! free acidic elem5t 7! qu>tz7 into ! s& & gravel b$s1 & 7#d7 ! conc5tration ( a l>ge "p ( ! e>?y basic elem5t 7! calcium1 magnesium1 & iron oxides7 into ! calc>e\s1 magnesian1 & iron deposits1 :ile 7#e7 a l>ge "p ( ! alkal9e basic rema9d] 7! sodium1 & potassium oxides7 is dissolv$ & held 9 ! sea-wat]4 ,physically1 ! great features are 7#a7 ! disaggregation ( ! antec$5t rock1 & 7#b7 ! sep>ation f "o ano!r ( products :i* are physically unlike1 t is1 ! co>s] f ! f9]1 & ! heavi] f ! light]1 & 7#c7 ! aggregation ( ^! div]se mat]ials 9 m or less di/9ct b$s4 ,x is to be not$ t :ile ! re>rangem5t ( ! s$im5ts is made on ! basis ( _! physical *>act]s1 x results 9 *emical diff]5tiation z well1 = ! products ( rock decay1 :i* are physically div]se1 are (t5 *emically div]se z well4 ,! physical assortm5t & ! /ratification are to be look$ ^u z a /ep 9 ! direction ( a simpl] gr\p+ ( ! mat]ial4 ,on ! :ole1 ! process is desc5sional 9 "*4 ,,! ,,reasc5sional ,,process4 ,runn+ h& 9 h& ) ?is desc5sional process1 !re has always be5 a reasc5sional process by :i* ! coh]5ce1 ! cry/allization1 & 9 "s measure ! complex composition ( ! rocks are re/or$4 ,?is is p>tially due to ext]nal me*anical ag5cies1 b *iefly to int]nal *emical & molecul> =ces4 ,two g5]al phases ( ?is recon/ructional "w are recogniz$4 ,! fir/1 simple/ & mo/ univ]sal1 is t by :i* ! incoh]5t mat]ials produc$ by ! desc5sional processes1 i4e41 ! muds1 s&s1 & cla/ic mat]ials g5]ally1 are h>d5$ into firm1 coh]5t %ales1 s&/ones1 & lime/ones1 & incid5tally m or less *ang$ 9 composition & molecul> arrangem5t4 ,! second is t by :i* m pr(\nd *anges ( induration & ( composition are wr\ght1 br++ ! rock back to a /ate resembl+ its orig9al cry/all9e "*4 ,?is is kn[n z metamorphism4 ,(t51 h[ev]1 x is b an ext5sion & int5sification ( ! m common processes ( ! fir/ class4 ,metamorphism is ess5tially recon/ruction4 ,induration "u ord9>y pressures & temp]atures4--,all k9ds ( loose fragm5tal mat]ial1 :e!r soils1 e>?s1 clays1 s&s1 gravels1 volcanic a%es1 c9d]s1 or o!r =ms ( cla/ic or pyrocla/ic mat]ial1 may become h>d5$ into firm rock ei!r by pressure1 or by cem5tation1 or by bo?4 ,pressure & cem5tation commonly act toge!r & aid ea* o!r4 ,! ord9>y pressures arise f ! weight ( ! ov]ly+ mat]ial1 & ^! ( c\rse increase ) dep?4 ,extraord9>y pressures arise f ! %r9kage ( ! e>? & p]haps f o!r s\rces4 ,! fragm5ts ( ! cla/ic mat]ial1 on be+ press$ toge!r = long p]iods1 weld m or less at ! po9ts ( contact4 ,if !y are irregul>1 angul>1 or elongate1 !y come to int]lock m or less l ! fragm5ts ( macadam1 & ?is cop]ates ) ! weld+4 ,! process is greatly aid$ by wat]-be>+ solutions ( lime1 silica1 etc4 :i* are deposit$ at ! po9ts :]e ! fragm5ts press ^u ea* o!r4 ,x is "h t ! capill>y spaces are mo/ m9ute & deposition is mo/ liable to take place4 ,sometimes a film ( m9]al matt] is laid d[n ov] ! surfaces ( ! fragm5ts & s]ves to b9d !m toge!r4 ,?is process goes on :]ev] ! gr\nd-wat]s are 9 a deposit+ condition1 j z ! opposite process ( dis9tegration takes place :]ev] ! wat]s are 9 a solv5t /ate4 ,at & ne> ! surface ( ! l&1 ! wat]s are usually 9 ! latt] condition & dis9tegration is 9 progress1 z already not$1 b ?is is n always s4 ,at times & places1 ! wat] f )9 ! rock-mass may come to ! surface & evaporate1 & 9 s do+ leave all its dissolv$ mat]ial on ! surface1 or )9 ! out] pores ( ! mass1 z cem5t+ mat]ial4 ,! ext]ior ?us becomes firmly b\nd toge!r1 8case-h>d5$10 z x is t]m$4 ,?is may be se5 9 ! dry+ ( a lump ( mud1 ! ext]ior ( :i* (t5 becomes q firm4 ,x is se5 9 qu>ry-rock1 especially s&/one1 :i* is sometimes s(t & easily work$ :5 tak5 wet f ! e>?1 b :i* h>d5s z ! wat]--! 8sap0 ( ! qu>rym5--dries out & deposits its solutes 9 ! capill>y spaces ( ! gra9s ( ! surface4 ,x is obvi\s t x is ! v la/ ( ! 8sap0 :i* conta9s ! mo/ conc5trat$ solutes1 & t ?is la/ remnant is held 9 ! m9ute capill>y spaces :]e ! gra9s t\* ea* o!r1 & h5ce ! la/ /age ( dry+ leaves ! cem5t at ! po9ts :]e x is mo/ effective4 ,9 natural exposures ( s&/one1 ! pores ( ! out] %ell sometimes become almo/ completely fill$ 9 ?is way ) silici\s deposits1 & ! s&/one is *ang$ into a qu>tzite4 ,9 ! sea1 & 9 ! deep wat] und]gr\nd1 ! common habit ( ! wat] is to deposit m ?an to dissolve1 ?\gh x is do+ m or less ( bo?4 ,z a rule1 !re=e1 loose mat]ial 9 ^! situations becomes b\nd m or less firmly into rock1 & h5ce :at 7 orig9ally loose s& b$s become s&/ones2 :at 7 s(t muds become %ales or lime/one1 accord+ to composition2 :at 0 gravel becomes conglom]ate2 :at 0 *ip/one becomes breccia2 :at 7 volcanic a%es1 c9d]s1 & lapilli become tuffs2 & :at 7 masses ( volcanic blocks & co>se fragm5ts become agglom]ates4 ,illu/ration3 ,fig4 #ced4--,qu>tz cry/al enl>g$ by second>y gr[?4 ,! %ad$ outl9e repres5ts ! outl9e ( ! s& gra92 ! solid l9es1 ! outl9e aft] second>y gr[?4 ,magnifi$ #fg diamet]s4 7,van ,hise47 ,fig4 #cee4--,s&/one & qu>tzite texture4 ,! %ad$ outl9es repres5t ! surfaces ( ! s& gra9s be=e gr[?1 ! int]v5+ :ite portions1 ! add$ qu>tz1 & ! black portions1 unfill$ spaces4 ,op5 spaces *>act]ize s&/one4 ,:5 ! spaces are fill$ ) qu>tz1 ! rock becomes qu>tzite4 ,magnifi$ #ce diamet]s4 7,van ,hise47 ,! cem5t+ process works at times 9 specially int]e/+ ways4 ,9 qu>tz s&/ones1 ! gra9s are worn fragm5ts ( qu>tz cry/als1 =m$ orig9ally 9 qu>tz-be>+ rock4 ,! cry/all9e =ce 9 ^! remnants controls ! arrangem5t ( ! new molecules ( silica deposit$ ab\t !m4 ,! result is t ! new deposits t5d to build up ! orig9al =ms ( ! cry/als f :i* ! s& gra9s 7 d]iv$ 7,fig4 #ced74 ,sometimes a film ( iron oxide has =m$ ab\t ! gra9 ( s& be=e ! addition ( ! new silica4 ,?is1 or "s diff]5ce ( color1 may cle>ly di/+ui% ! orig9al gra9 f subsequ5t additions4 ,sometimes ! adjac5t gra9s ( s&/one are rebuilt 9 ?is way until ! int]/ices are completely fill$4 ,:5 ?is has be5 accompli%$1 ! s&/one becomes a qu>tzite 7,fig4 #cee74 ,mo/ qu>tzites inde$ appe> to h be5 =m$ 9 ?is way1 b ma9ly "u special conditions t promote ! deposition ( silica4 ,gra9s ( o!r m9]als1 su* z feldsp>1 are subject to simil> second>y enl>gem5t 7,fig4 #cef74 ,illu/ration3 ,fig4 #cef4--;,feldsp> cry/als enl>g$ by second>y gr[?4 ,magnifi$ #ej diamet]s4 ,,aa orig9al gra9s2 ,,bb enl>gem5ts2 ,d unfill$ spaces4 7,van ,hise47 ,sometimes ! new mat]ial is deposit$ 9 ! =m ( conc5tric %ells ab\t ! p>ticles ( s$im5t1 build+ !m up into little sph]es4 ,rock =m$ ( su* sph]ules is kn[n z oolite1 f ! resemblance ( ! gra9s to ! roe ( fi% 7,fig4 #ceg74 ,sometimes ! nuclei ( ! concretions are gra9s ( qu>tz s&1 & ! add$ conc5tric lay]s are ( calcium c>bonate4 ,9 ?is case ! /ructure is q obvi\s2 b p]haps m frequ5tly ! nuclei are m9ute & difficult to id5tify1 & ! conc5tric %ells make up ! ma9 mass ( ! gra9s4 ,c]ta9 =mations1 z ! oolitic lime/one ( ,indiana & else:]e1 & ! ,upp] & ,l[] ,oolites ( ,engl&1 are *>act]iz$ by ?is /ructure4 ,9 mo/ cases ^! accretions probably grew 9 deposit+ wat]s t g5tly roll$ ! gra9s :ile lay]s 7 be+ add$4 ,!y ?us d n fall "u ! head ( cem5tation aft] ! b$s 7 =m$2 b conc5tric additions to ! gra9s appe> sometimes to h tak5 place aft] !y 7 =m$ into b$s4 ,cavity fill+4--,:5 cavities ( "s size occur 9 rocks & ! p]colat+ wat]s are 9 a deposit+ /ate1 ! int]iors ( ! cavities are sometimes l9$ ) conc5tric lay]s ( deposit4 ,"h1 in/ead ( build+ out f a nucleus1 ! wat]s build 9 f ! walls ( ! cavity4 ,! agate /ructure 7,fig4 #ceh7 is a case ( ?is k9d1 9 :i* ! successive lay]s are commonly silica 9 ! =m ( *alc$ony & diff] f ea* o!r 9 color & texture4 ,(t5 be=e ! cavity is entirely fill$1 ! deposit *anges f *alc$ony1 to cry/als ( qu>tz1 :i* gr[ ) _! bases on ! walls & _! pyramidal po9ts t[>d ! c5t] ( ! cavity4 ,geodes are examples ( a simil> process 9 :i* ! cavity is b p>tially fill$ ) cry/als :i* h _! bases set on ! walls ( ! cavity & _! po9ts direct$ inw>ds 7,fig4 #cei74 ,! cry/als ( geodes are mo/ commonly qu>tz or calcite1 b !y may be any o!r m9]al t ! wat]s are capable ( deposit+4 ,v l>ge cavities l9$ 9 ?is way are kn[n to m9]s z vuggs1 & ^! grade on into caves l9$ ) cry/als & ) /alactite & /alagmite4 ,^! are ! l>ge/ expression ( ! solidify+ process by means ( int]nal deposition4 ,illu/ration3 ,fig4 #ceg4--,oolitic texture4 ,ab\t natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #ceh4--;,agate /ructure4 ,! cavity 0 fir/ coat$ ) m9]al matt] deposit$ f solution4 ,! contract$ cavity 0 !n ne>ly fill$ ) ! same sort ( mat]ial deposit$ 9 lay]s1 app>5tly ov] ! bottom1 until ! cavity 0 ne>ly oblit]at$4 ,fissure-fill+2 ve9s4--,cracks1 crevices1 & fissures fill$ by deposition 9 a simil> way give rise to ve9s 7,fig4 #cfj74 ,"h ! fill+ gr[s f ! walls t[>d ! c5t]1 & h5ce (t5 has a b&$ appe>ance4 ,by ?is fill+ ( cracks & crevices1 ! circulat+ wat] heals ! breaks 9 ! rocks4 ,frequ5tly a cru%$ zone is ?us re/or$ to a solid /ate4 ,:5 ! fissures are deep & wide & trav]se diff]5t =mations1 conditions are af=d$ = v complex deposits1 & = ! conc5tration ( r>e & valuable mat]ial orig9ally disp]s$ ?r\gh a great mass ( rock4 ,ore deposition 9 su* ve9s is usually treat$ z a !me by itself1 b x is really b a decl>$ expression ( ! "w :i* ! p]colat+ wat]s are do+ ?r\gh\t all ! rocks :i* !y p5etrate4 ,mo/ ( ! f9e cry/als t grace m9]alogical collections 7 =m$ 9 cavities & fissures by deposition f circulat+ m9]aliz$ wat]s4 ,illu/ration3 ,fig4 #cei4--;,a geode4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,solution z well z deposition4--,a fur!r phase ( ! process ne$s att5tion4 ,! p]colat+ wat]s are con/antly tak+ up matt] z well z ?r[+ x d[n1 & s1 :ile !y are cem5t+ fragm5ts toge!r & heal+ fractures1 !y are also remov+ mat]ial1 & a rock may be gr[+ por\s & cav]n\s at ! same "t t its fragm5ts are be+ unit$4 ,cavities may be =m$ at "o /age & fill$ at ano!r2 matt] may be tak5 up at "o po9t & put d[n at ano!r1 & s an int]nal recon/ruction is 9 sl[ progress4 ,illu/ration3 ,fig4 #cfj4--,ve9s ( calcite 9 lime/one4 ,calcif]\s =mation ne> ,highgate ,spr+s1 ,vt4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,concretions4--,a notable phase ( ?is int]nal recon/ruction is ! assembl+ toge!r ( l k9ds ( matt]4 ,= in/ance1 silica t 0 probably deposit$ 9 ! =m ( ! silici\s %ells & spicules ( plants & animals1 & 0 dissem9at$ ?r\gh ! s$im5ts z orig9ally =m$1 is aggregat$ into nodules ( *]t or fl9t 7,fig4 #cfa72 simil>ly1 concretions ( f]r\s c>bonate or calcium c>bonate gr[ 9 s&s1 silts1 or muds2 clu/]s ( cry/als ( pyrite 7,fe,s71 ( sphal]ite 7,zn,s71 & gal5ite 7,pb,s7 are =m$ 9 clayey lay]s1 press+ ! clay back z !y gr[2 & 9 _m o!r cases1 k9d comes to k9d4 ,"s concretions probably =m dur+ ! accumulation ( ! b$s 9 :i* !y lie4 ,replacem5ts & pseudomorphs4--,s also !re are replacem5ts1 sometimes result+ 9 imitative or false =ms4 ,frequ5tly ! calcium c>bonate ( corals1 molluscan %ells1 etc41 is replac$ by silica1 & ?is sub/itution is br\ght ab\t s gradually1 p>ticle by p>ticle1 t ! m9ute/ details ( /ructure are sometimes fully pres]v$4 ,?is is (t5 ( great s]vice 9 _! /udy1 s9ce ! lime/one 9 :i* !y are imb$d$ may (t5 be dissolv$ away1 :ile ! silicifi$ fossil is unaffect$4 ,s woody matt] is sometimes replac$ by silica1 =m+ silicifi$ wood4 ,simil>ly1 ! molecules ( "o cry/al are sometimes replac$ by diff]5t mat]ial1 z ! molecules ( calcite by z9c c>bonate1 giv+ a pseudomorph ( z9c c>bonate aft] calcite4 ,illu/ration3 ,fig4 #cfa4--,nodule ( *]t4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,incipi5t cry/allization4--,a m g5]al *ange is incipi5t cry/allization4 ,"s common lime/ones & dolomites are n[ l>gely made up ( small cry/als1 ?\gh ! mass 0 orig9ally a calc>e\s mud or ooze4 ,incipi5t cry/als are =m$ 9 %ales & o!r s$im5ts4 ,?is process1 l ! prec$+1 is a k9d ( incipi5t metamorphism or recon/ruction1 b x is a p]vasive process1 tak+ place "u ord9>y conditions ( heat & pressure1 & ?r\gh ! ag5cy ( circulat+ gr\nd-wat]s4 ,by ^! & simil> processes ! fragm5tal deposits are solidifi$ into firm rock & und]go int]nal *anges :i* m or less reorganize ! matt] ( :i* !y are compos$4 ,! process is a v sl[ "o usually4 ,"s ( ! s&s & muds ( v e>ly geologic ages are yet imp]fectly solidifi$2 e4g41 mu* ( ! ,/4 ,pet]'s s&/one1 a v anci5t =mation1 is yet s incoh]5t z to break d[n into s& 9 be+ dug out1 & is us$ = mort> s& mu* m ?an = build+ /one4 ,"s ( ! ,hudson ,riv] %ales ( sc>cely less age are m ne>ly clay ?an h>d rock4 ,b ^! are examples ( excessive sl[ness & slightness ( *ange4 ,9 g5]al1 all b ! mo/ rec5t deposits %[ notable progress 9 recon/ruction4 ,illu/ration3 ,fig4 #cfb4--;,figure %[+ ! elongation ( pebbles result+ f pressure4 ,c>bonif]\s =mation1 ,bancr(t ,place1 ,newport1 ,r4 ,i4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,recon/ruction "u ,exceptional ,conditions4 ,two special conditions greatly influ5ce *anges 9 rocks1 viz41 pressure & heat4 ,_! action gives rise to ?ree g5]al cases1 b ^! bl5d indef9itely3 7#a7 exceptional pressure )\t great heat1 7#b7 great heat )\t exceptional pressure1 & 7#c7 great heat & great pressure conjo9$4 ,exceptional pressure may arise f ! weight ( ov]ly+ rocks1 or f lat]al ?ru/ due to ! %r9kage ( ! globe1 & occasionally f o!r causes4 ,exceptional heat may arise f pressure1 f ! intrusion ( hot lavas1 & occasionally f o!r s\rces4 ,9 ! case ( intrud$ lavas !re may or may n be exceptional pressure4 ,?ru/ usually gives heat z well z pressure1 b if lat]al ?ru/ acts on rocks ne> ! surface1 !y may be ma%$ into new =ms )\t becom+ v exceptionally heat$1 ?\gh "s rise ( temp]ature is inevitable4 ,illu/ration3 ,fig4 #cfc4--,pre-,cambrian fossilif]\s slate4 ,deep ,creek ,canyon1 #af miles s\!a/ ( ,t[ns5d1 ,mont4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 7#a7 ,slaty /ructure4--,:5 rocks made up ( cla/ic p>ticles are compress$ 9 a giv5 direction & are relatively free to exp& at "r angles to ! direction ( pressure1 ! p>ticles t are already elongat$ t5d to take positions ) _! long] axes at "r angles to ! direction ( pressure1 & all p>ticles1 :e!r elongate or n1 are m or less flatt5$ 9 a plane transv]se to ! direction ( pressure4 ,?is may be readily se5 :]e ! p>ticles are l>ge 7,fig4 #cfb74 ,z a result ( ! ori5tation & flatt5+ ( _! p>ticles1 rocks s affect$ split m readily betwe5 ! elongate & flatt5$ p>ticles ?an across !m4 ,9 o!r words1 ! rocks cleave along planes normal to ! direction ( compression1 & break ) difficulty & ) r\gh fracture across ! planes ( cleavage4 ,! condition ?us induc$ is kn[n z slaty /ructure 7,fig4 #cfc71 & is be/ illu/rat$ by ro(+-slate1 :i* 0 orig9ally a mud1 lat] a %ale1 & f9ally assum$ ! slaty condition "u /rong compression4 ,sometimes ! orig9al b$d+ may /ill be se5 runn+ across ! induc$ cleavage planes 7,fig4 #cfd74 ,z ! orig9al mud b$s 7 horizontal or ne>ly s1 & z ! ?ru/ is usually horizontal or ne>ly s1 ! induc$ cleavage commonly crosses ! b$d+ planes at a high angle 7,fig4 #cfd72 b aft] ! b$s are tilt$ or b5t1 ! l9es ( pressure take new directions relative to ! b$d+ planes1 & ! angles betwe5 ! orig9al b$d+ & ! slaty cleavages usually become small]1 & may ev5 disappe> 9 exceptional cases4 ,lime/ones1 s&/ones1 & conglom]ates are n s easily compress$ z mud/ones1 & !y usually take on only an imp]fect cleavage normal to ! direction ( pressure4 ,(t5 !y m]ely %[ "s little compact+1 :ile ! %aly /rata betwe5 !m are conv]t$ into slate4 ,obvi\sly ! direction ( slaty cleavage may be us$ to det]m9e ! direction ( ! compress+ =ce1 & is ?us s]viceable 9 dynamic /udies4 ,illu/ration3 ,fig4 #cfd4--,slaty /ructure & its relation to b$d+ planes4 ,two miles s\? ( ,wall&1 ,t5n4 7,kei?1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cfe4--;,foliat$ rock4 7,ells1 ,c4 ,geol4 ,surv47 ,foliation1 s*i/osity4--,a m int5se application ( pressure 9 a giv5 direction is capable ( break+ d[n & de=m+ ! mo/ resi/ant rock4 ,?is mu/ necess>ily be att5d$ ) ! evolution ( mu* heat1 & !rmal effects are m+l$ ) pressure effects1 b ! !rmal effects may be neglect$ = ! mom5t4 ,! fir/ /age ( ! me*anical effect ( ! compression may be to cru% ! rock m or less4 ,x ?us becomes granul> or fragm5tal1 & is really a peculi> species ( cla/ic rock 7autocla/ic74 ,at a fur!r /age1 ! fragm5t$ mat]ial may be press$ into lay]s or leaves1 mu* z 9 ! developm5t ( slaty cleavage1 b z a result ( ! nature ( ! mat]ial1 ! cleavage is less p]fect4 ,?is is (t5 att5d$ by m or less %e>+ ( ! mat]ial ^u itself1 & ?us a rude fissility & foliation is develop$4 ,! result1 includ+ ! att5dant metamorphism ab\t to be describ$1 is a foliat$ or s*i/ose /ructure 7,figs4 #cfe & #cff74 ,ev5 ! mo/ massive rocks may be r$uc$ to ! foliat$ =m by ?is process2 ?us1 a granite may be ma%$ into a gneiss--:i* is a granite 9 composition1 b has a foliat$ /ructure--or a basalt may be conv]t$ into a s*i/1 a common t]m = foliat$ cry/all9e rocks4 ,porphyritic rock r5d]$ s*i/ose by pressure is %[n 9 ,fig4 #cff4 ,:5 massive rocks l granite or basalt are ?us cru%$ d[n into ! foliat$ =m1 ! process is 9 a s5se degradational4 ,x is a k9d ( katamorphism or d[nw>d *ange4 ,x is (t5 difficult to diff]5tiate ! s*i/s ?us d]iv$ by degrad+ massive rocks1 f ^? develop$ by asc5sional processes f cla/ic =mations 7anamorphism74 ,! action ( heat is important 9 ! evolution ( s*i/s ( bo? classes1 b ! effects ( heat may be/ be tak5 up :]e x acts measurably alone4 ,illu/ration3 ,fig4 #cff4--,porphyry r5d]$ s*i/ose by pressure4 ,ne> ,gre5 ,p>k1 ,caldwell ,co41 ,n4 ,c4 7,kei?1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cfg4--,s*i/ose /ructure develop$ by pressure %[n 9 ! left half ( ! figure1 :ile x is want+ 9 ! "r half4 ,! v]tical l9e is a b$d+ plane4 ,! lay] to ! left 0 ( suffici5tly diff]5t composition or subject to suffici5tly diff]5t movem5t to develop s*i/osity1 :ile t to ! "r 0 brok5 7brecciat$7 in/ead4 ,! rock at ! left w\ld be call$ qu>tz s*i/1 :ile t at ! "r is qu>tzite4 ,huronian =mation ne> ,ableman1 ,wis4 7,atwood47 ,metamorphism by heat4--,:5 a mass ( lava is p\r$ out ^u ! surface1 x bakes ! mantle-rock :i* x ov]runs1 9 great] or less degree1 dep5d+ on ! mass & temp]ature4 ,! nature ( ! effect is mu* ! same z 9 ! process ( brick-mak+1 a dehydration ( ! mat]ial1 a h>d5+ ( ! loose matt] by ! p>tial weld+ ( ! p>ticles1 & sometimes ! p>tial fusion ( ! surface & ! developm5t ( new comp\nds1 usually glassy1 b sometimes p>tially cry/all9e4 ,9 bo? ! natural & ! artificial process1 ! "t elem5t is %ort1 ! pressure trivial1 & ! wat] action limit$4 ,if ! heat 7 to become suffici5tly int5se1 ! result w\ld be fusion1 i4e41 a lava :i* w\ld solidify into a glass4 ,9 su* a case1 ! rock cycle w\ld be c>ri$ back to ! initial molt5 /ate & a new cycle in/itut$1 b ?is does n usually take place :5 lava m]ely ov]fl[s ! surface4 ,if lavas1 in/ead ( ris+ to ! surface1 w$ge 9 betwe5 lay]s ( rock & =m sills1 or int]/ratifi$ %eets1 ! surface above z well z t bel[ is bak$1 & z ! excess ( heat ( ! lava c only escape ?r\gh ! neighbor+ rock1 ! effects = a giv5 mass ( lava are m consid]able1 & z ! "t elem5t & ! wat] action 7& sometimes ! pressure7 are usually great] ?an 9 ! case ( extrud$ lavas1 ! effects t5d r t[>d *emical & cry/all9e *ange ?an to simple bak+4 ,?is t5d5cy increases ) increase 9 ! mass ( ! lava & 9 its temp]ature4 ,sometimes enorm\s masses ( v hot lava are ?ru/ 9 betwe5 or among ! /rata t lie b5ea? ! surface1 & br+ to be> ^u !m int5se heat = a long p]iod4 ,s also1 :5 a v5t or fissure is ! passageway = lavas t cont9ue to come to ! surface = long p]iods1 z 9 ! case ( p]si/5t volcanoes1 ! rocks :i* =m ! walls ( ! v5t or fissure are heat$ = a long "t1 & ?is gives rise to metamorphism ?r\gh heat1 )\t v unusual pressure1 b usually ) ! free aid ( wat]4 ,9 ^! cases ! *ief effect is *emical recomb9ation & cry/allization4 ,9 ! lime/ones & s&/ones x is simple2 9 ! %ales m complex4 ,9 pure lime/ones & dolomites little *emical *ange takes place1 b ! molecules are re>rang$ into l>g] & m p]fect cry/als1 & m>ble is ! result4 ,! co>s5ess ( ! cry/als is1 9 a g5]al way1 a measure ( ! l5g? ( "t dur+ :i* ! heat acts1 & ( its int5sity1 b mu* dep5ds on ! fre$om ( ! att5dant wat] circulation4 ,cry/als an in* or two across are sometimes =m$ 9 ! contact zone1 :]e ! att5dant wat] action is important4 ,if impurities1 z silica1 alum9a1 iron1 etc41 are pres5t1 v>i\s m9]als1 su* z tremolite & act9olite1 may be =m$ 9 ! m>ble4 ,9 pure qu>tzose s&/ones1 ! effect is to cause ! build+ up ( ! qu>tz gra9s until ! int]spaces are ess5tially fill$ & ! :ole becomes a massive qu>tzite4 ,"h1 z 9 ! m>bles1 impurities =m adv5titi\s cry/als1 a v common "o be+ hematite1 =m$ f ! segregation ( ! f]ric oxide ( ! s&/one4 ,9 ! %ales1 ! mat]ial to be act$ ^u is m complex1 =1 :ile ! ma9 mass is an alum9um silicate1 !re is usually mu* free qu>tz1 n a little pota% & iron1 & m or less ( lime1 magnesia1 soda1 & o!r +r$i5ts1 = ! muds f :i* ! %ales arose conta9$ n only ! fully decompos$ matt] ( ! orig9al cry/all9e rocks1 b ! f9e matt] worn f !m by w9d & wat] )\t decomposition4 ,:5 ?is mix$ matt] is act$ ^u by high heat & moi/ure1 x t5ds to return to its orig9al cry/all9e /ate1 s f> z its *ang$ con/itution p]mits4 ,! pota% *iefly unites ) alum9a & silica1 & =ms pota% feldsp> 7or?oclase *iefly7 & pota% mica 7muscovite74 ,! iron (t5 unites ) magnesia1 alum9a1 & silica to =m biotite or "o ( ! f]romagnesian m9]als1 *iefly an amphibole4 ,! lime usually aids 9 ! =mation ( o!r silicates ( ei!r ! feldsp> or ! f]romagnesian gr\p1 :ile ! surplus silica cry/allizes into qu>tz4 ,!re is usually a pr$isposition to =m mica 9 pref]5ce to o!r silicates if ! prop] con/itu5ts are pres5t1 & ! result is t mica s*i/s & gneisses1 9 :i* mica ab\nds1 are common products ( ! metamorphism ( %ales by contact ) bodies ( lava4 ,mica s*i/s & micace\s gneisses are also =m$ 9 o!r ways1 & o!r s*i/s1 dep5d5t on ! composition ( ! %ales1 are =m$ ab\t intrusions ( igne\s rock4 ,9 all su* cases pressure probably att5ds ! heat & is a factor 9 ! developm5t ( ! s*i/s4 ,:5 ! *ange induc$ by ! heat is less consid]able1 ! %ale is bak$1 ) incipi5t recry/allization1 & (t5 takes ! =m ( argillite1 a compact1 massive sort ( %ale4 ,b$s ( hydr\s iron oxide 7limonite7 or ( iron c>bonate 7sid]ite7 are usually conv]t$ by heat into hematite or magnetite4 ,b$s ( peat1 lignite1 & bitum9\s coal are conv]t$ into an?racite by ! driv+ (f ( ! volatile hydroc>bons4 ,if ! process goes to ! extreme1 graphite is ! result4 ,metamorphism by heat & lat]al pressure4--,z already indicat$1 ! m common int5se pressures exp]i5c$ by rocks at & ne> ! surface are ^? t come f lat]al ?ru/s aris+ f ! %r9kage ( ! e>?4 ,^! affect "o dim5sion ( ! rock-mass1 :ile !y p]mit x to exp& 9 "o or bo? ( ! o!r dim5sions4 ,?is produces a /ra9 9 all ! con/itu5t p>ticles ( ! rock1 & "u su* /ra9 !y pass m readily into solution ?an :5 free f /ra91 & m readily re>range _! molecules int]nally into positions ( less /ra94 ,! cry/als gr[ mo/ freely along ! planes ( lea/ /ress1 i4e41 at "r angles to ! pressure4#bjb ,z a consequ5ce1 :]e unidim5sional pressure & high heat result+ f ! compression unite _! influ5ce1 ! metamorphic *anges are n only facilitat$1 b ! re>rangem5t is controll$ by ! pressure & results 9 a p>allel arrangem5t ( ! con/itu5t cry/als1 giv+ a foliat$ or s*i/ose "* to ! new rock4 ,! *anges !mselves are mu* ! same z ^? produc$ by heat & wat] )\t exceptional pressure1 ?\gh "s di/9ctions may be not$4 ,x is to be obs]v$1 h[ev]1 t two k9ds ( "w are embrac$ "h3 ! metamorphism ( cla/ic rocks into cry/all9e s*i/s1 :i* may be reg>d$ z an upbuild+ process1 anamorphism1 & ! ma%+ d[n ( massive cry/all9e rocks into s*i/s1 :i* may be reg>d$ z a degradational process1 katamorphism4 ,9 bo? cases1 h[ev]1 !re is solution & re>rangem5t ( ! molecules4 ,! katamorphism ( basalts & o!r basic rocks gives basic s*i/s2 t ( granitic & simil> rocks gives gneisses4 ,! anamorphism ( basic pyrocla/ic tuffs & wackes gives basic s*i/s1 :ile t ( acid pyrocla/ics & mo/ %ales gives gneisses1 mica s*i/s1 or simil> acidic s*i/s4 ,x is obvi\s t ord9>y %ales _c usually become basic s*i/s1 because 9 produc+ ! orig9al muds1 ! bases 7 g5]ally remov$2 b :5 %ales are highly calc>e\s & magnesian1 z :5 !y grade t[>d ! lime/ones & dolomites1 !y may become basic s*i/s by metamorphism1 e4g41 c]ta9 hornbl5dic s*i/s4 ,x is ev5 m obvi\s t ! lime/one & s&/one =mations mu/ l>gely reta9 _! di/9ct composition4 ,x is ?us se5 t1 9 g5]al1 a s$im5t>y s]ies anamorphos$ mu/ diff] f a cry/all9e s]ies katamorphos$1 ?\gh bo? give rise to foliat$ or s*i/ose rocks4 ,deep-seat$ metamorphism4--,:5 ! exceptional pressure arises f ! weight ( rocks felt at great dep?1 x is practically equal 9 all directions & ! cry/allization probably develops normally & is n =c$ into ! p>allel or foliat$ =m4 ,rocks metamorphos$ "u ^! conditions probably t5d to take ! massive =m r ?an ! s*i/ose =m1 b ?is conclusion is !oretical r ?an obs]vational1 = little or no?+ is kn[n ( ! hi/ory ( su* rocks4 ,completion ( ! rock cycle4--,! cry/alliz+ processes ( metamorphism are fundam5tally simil> to ! processes by :i* rocks cry/allize out ( magmas1 only 9 ! fir/ case ! "w is done *iefly by ! aid ( an aque\s solution1 :ile 9 ! second x is done ?r\gh a mutual solution ( ! con/itu5ts 9 !mselves1 :]e wat] 0 b an incid5t4 ,if ! heat factor 9 metamorphism be suffici5tly increas$1 aque\s solution may actually grade into magmatic solution ?r\gh v>i\s degrees ( s(t5+ & melt+1 & ! cycle ( *anges be clos$ 9 ^u itself4 ,,v>i\s ,,classifications ,,& ,,nom5clatures4 ,f ! =ego+ sket* ( ! processes ( rock-mak+ x may easily be inf]r$ t ! v>ieties ( rocks may be almo/ unlimit$1 & t !y may be def9$1 nam$1 & classifi$ on _m diff]5t bases2 = example4 7#a7 ,if ! mode ( orig9 is *iefly 9 m9d1 rocks may be class$ z igne\s 7lavas1 tuffs1 etc472 metamorphic 7s*i/s1 gneisses1 an?racite1 magnetite1 etc472 aque\s 7wat]-laid s$im5ts1 /alactites1 trav]t9e1 etc472 eolian 7dunes1 loess 9 "p72 glacial 7till1 mora9es72 cla/ic 7mantle-rock1 s&/one1 conglom]ate1 etc472 organic 7peat1 lignite1 coal1 etc41 & indirectly1 lime/one1 *alk1 infusorial e>?1 etc472 & s on4 7#b7 ,if ! textural or /ructural *>act]s are 9 m9d1 rocks are designat$ vesicul> 7pumice1 scoria1 etc472 rhyolitic 7fl[-/ructure rocks72 glassy 7obsidian1 ta*ylite72 porphyritic 7di/9ct cry/als 9 obscure matrix72 granitic 7well-gra9$72 compact1 por\s1 e>?y1 ar5ace\s 7s&y71 s*i/ose1 etc4 7#c7 ,if ! *emical composition is *iefly reg>d$1 !y may be class$ z silici\s1 calc>e\s1 c>bonace\s1 f]rug9\s1 etc42 or1 if ! *emical nature is consid]$1 !y are gr\p$ z acidic1 basic1 or neutral4 7#d7 ,if ! cry/all9e "* is made ! basis1 !y are designat$ phan]ocry/all9e 7di/9ctly cry/alliz$71 microcry/all9e 7m9utely cry/alliz$71 cryptocry/all9e 7hidd5ly cry/alliz$71 & amorph\s 7non-cry/all9e74 7#e7 ,if att5tion is fa/5$ on c]ta9 +r$i5ts1 rocks are *>act]iz$ z qu>tzose1 micace\s1 *loritic1 talcose1 pyritif]\s1 g>netif]\s1 etc4 7#f7 ,:5 rocks are reg>d$ z m9]al aggregates1 if 7a7 ! aggregates are simple1 !y are nam$ f ! dom9ant m9]als1 z dolomite1 hornbl5dite1 g>netite1 anor?ite1 etc42 & if 7b7 ! aggregates are complex !y take special names1 z sy5ite 7or?oclase & hornbl5de71 gabbro 7plagioclase feldsp> & pyrox5e71 etc4 7#g7 ,:5 ! po9t ( view is /ructure ( ! mass1 !y are class$ z massive1 /ratifi$1 %aly1 lam9at$1 slaty1 foliat$1 s*i/ose1 etc4 7#h7 ,:5 physical /ate or g5esis is consid]$1 !y are gr\p$ z cla/ic1 fragm5tal1 or detrital 7conglom]atic1 brecciat$1 ar5ace\s1 argillace\s1 etc472 or pyrocla/ic 7tuface\s1 scoriace\s1 agglom]atic72 or massive1 9 a s5se slightly diff]5t f t above 7#g74 ,z sometimes "o ( ^! *>act]i/ics & sometimes ano!r is mo/ important 9 a giv5 rock1 or 9 a giv5 /udy1 no "o classification is satisfactory 9 all cases1 yet ea* has its advantages 9 p>ticul> cases4 ,new ,sy/em ( ,classification & ,nom5clature4 ,! pres5t sy/ems ( classify+ & nam+ rocks h gr[n up gradually out ( e>li] & crud] me?ods1 _m ( :i* 7 inh]it$ f popul> usage4 ,mo/ ( ! names & def9itions came into use be=e microscopical & o!r mod]n means ( /udy 7 adopt$4 ,^! sy/ems1 !re=e1 reta9 _m inh]it$ crudities & inconsi/5cies1 & lack adaptation to pres5t ne$s4 ,!y are too complex & difficult = field use & = g5]al discussions1 :ile n suffici5tly exact & sy/ematic = ! m rigor\s petrological discussions4 ,a m adaptive & consi/5t practice has be5 e>ne/ly s\ght by petrologi/s1 & a new sy/em ( classification ( igne\s rocks has be5 (f]$ by a gr\p ( lead+ ,am]ican petrologi/s1 an outl9e ( :i* is "h giv54#bjc ,to "s ext5t ?is may be ext5d$ to ! metamorphic cry/all9e rocks ) necess>y modifications & additions4 ,! classification & nom5clature ( ! second>y rocks mu/ probably always rema9 v>iable & pla/ic to express ! v>i\s po9ts ( view :i* x is desirable to take4 ,dur+ ! transition to ?is or "s o!r new sy/em1 :i* seems inevitable1 ! app5d$ alphabetical ref]5ce li/s ( ! mo/ common m9]als & rocks1 ) brief def9itions 9 accordance ) curr5t usage1 w be f\nd s]viceable4 ,! propos$ sy/em includes two p>ts1 a field sy/em & a quantitative sy/em1 ! "o applicable to rocks on casual inspection1 & ! o!r1 only aft] detail$ /udy4 ,! propos$ field sy/em4 ,! propos$ field names are bas$ l>gely on texture & color4 ,! m9]al con/itu5ts are us$ = subdivisions :5 !y c be det]m9$2 o!rwise !y are neglect$4 ,classify+ *iefly on ! basis ( texture & cry/all9e /ate1 !re are ?ree gr\ps3 ,phan]ites1 9 :i* all ! lead+ m9]al con/itu5ts c be se5 megascopically2 aphanites1 9 :i* all1 or at lea/ an appreciable "p1 ( ! con/itu5t m9]als _c be di/+ui%$ megascopically2 & glasses1 9 :i* ! mat]ial is :olly or l>gely vitre\s4 ,i4 ,! ,phan]ites may be fur!r classifi$ by _! *ief m9]al con/itu5ts z foll[s3 #a4 ,granites 7f4n471#bjd consi/+ l>gely ( qu>tz & feldsp> ( any k9d1 ) or )\t mica1 hornbl5de1 pyrox5e1 or o!r m9]als4 ,?is diff]s f ! pres5t common use 9 n reg>d+ mica z an ess5tial con/itu5t1 & 9 n di/+ui%+ betwe5 alkali feldsp>s & calcic feldsp>s1 ?us broad5+ ! class4 #b4 ,sy5ites 7f4n471 consi/+ pr$om9antly ( feldsp> ( any k9d1 ) subord9ate am\nts ( hornbl5de1 mica1 or pyrox5e1 b ) little or no qu>tz4 ,?is diff]s f ! common use 9 giv+ hornbl5de a subord9ate place1 & 9 embrac+ rocks ) calcic feldsp>s1 ?us broad5+ ! class4 #c4 ,diorites 7f4n471 consi/+ pr$om9antly ( hornbl5de & subord9ately ( feldsp> ( any k9d1 ) :i* !re may be mica1 pyrox5e1 or o!r m9]als4 ,?is is ne>ly ! pres5t use except t any k9d ( feldsp> may =m ! subord9ate elem5t4 #d4 ,gabbros 7f4n471 consi/+ pr$om9antly ( pyrox5e & subord9ately ( feldsp> ( any k9d1 ) or )\t o!r m9]als4 ,?is ne>ly co9cides ) "o ( ! v>i\s pres5t uses ( ! t]m except t ! range ( ! feldsp> is increas$4 #e4 ,dol]ites#bje 7f4n471 consi/+ pr$om9antly ( any f]romagnesian m9]al n di/+ui%able z hornbl5de or pyrox5e1 ) subord9ate elem5ts ( feldsp> ( any k9d1 & ) or )\t o!r accessory m9]als4 ,a "n to be us$ :5 ! dom9ant m9]al is cle>ly f]romagnesian1 b _c be satisfactorily id5tifi$ z ei!r hornbl5de or pyrox5e1 al?\gh x may probably be "o ( ^!4 ,9 o!r words1 ! dol]ites 7deceptive7 embrace ! :ole diorite-gabbro gr\p :5 too obscure = sep>ation4 #f4 ,p]idotites1 consi/+ pr$om9antly ( oliv9e & f]romagnesian m9]als1 )\t feldsp>1 or ) v little4 #g4 ,pyrox5ite1 consi/+ ess5tially ( pyrox5e )\t feldsp> or oliv9e4 #h4 ,hornbl5dite1 consi/+ ess5tially ( hornbl5de )\t feldsp> or oliv9e4 ,,ii4 ,! ,aphanites may be non-porphyritic or porphyritic4 7a7 ,non-porphyritic aphanites :5 light-color$ may be class$ z felsites2 :5 d>k-color$1 z basalts4 7b7 ,! porphyritic aphanites or porphyries1 :5 light-color$1 are leucophyres2 :5 d>k-color$1 are melaphyres 7f4n474 ,!y may be classifi$ fur!r1 accord+ to ! k9d ( ph5ocry/ imb$d$ 9 ! aphanitic gr\nd-mass1 z ,qu>tz-porphyries1 or qu>tzophyres2 ,feldsp>-porphyries1 or feldspaphyres 7n felsophyres72 ,hornbl5de-porphyries1 or hornbl5dophyres2 & s on4 ,^! may be subclass$ by color1 z ,qu>tz-leucophyres1 light-color$ qu>tz-porphyries2 ,qu>tz-melaphyres1 d>k-color$ qu>tz-porphyries2 ,feldsp>-leucophyres2 ,feldsp>-melaphyres2 & s on4 ,,iii4 ,! glasses are classifi$1 accord+ to color & lu/]1 into obsidians or pit*/ones :5 d>k & lu/r\s2 p]lites1 :5 a sph]oidal fracture gives !m a pe>ly appe>ance2 & pumice :5 greatly inflat$ by includ$ gases4 ,9 g5]al discussions1 x is reg>d$ z s]viceable to use ! t]m granitoids 9 a broad g5]ic s5se1 to include all cry/all9e rocks ( ! g5]al granitoid type1 includ+ ! granites1 sy5ites1 gneisses1 etc4 ,9 a simil> broad way1 ! t]m gabbroids may be us$ to include ! d>k cry/all9e rocks 9 :i* ! f]romagnesian m9]als pr$om9ate1 z ! diorites1 gabbros1 dol]ites1 p]idotites1 etc4 ,9 ?is conv5i5t & compreh5sive way1 two contra/$ gr\ps ( igne\s rocks may be designat$4 ,z ! granitoids are usually acidic & ! gabbroids usually basic1 ! gr\p+ repres5ts a broad fact ( importance4 ,,! ,,propos$ ,,quantitative ,,sy/em4 ,! di/+ui%+ *>act]i/ic ( ! m rigor\s sy/em design$ to meet ! ne$s ( sci5tific petrology is its quantitative *emical "*4 ,all igne\s rocks are classifi$ prim>ily accord+ to _! *emical composition & only second>ily accord+ to _! m9]al con/itu5ts1 texture1 & o!r *>act]s4 ,! rigor\s application ( ! sy/em requires *emical analyses ( ! rocks1 b z ^! are n available 9 _m cases1 ! au?ors ( ! sy/em h devis$ a me?od ( optical m9]al analysis by :i* ! ne>ly exact proportions ( all ! con/itu5t m9]als c be det]m9$1 & by k ( _! *emical nature ! results may be conv]t$1 by computation1 into *emical t]ms4 ,?is c only be done = holocry/all9e rocks ^: cry/als are l>ge en\gh to be measur$ "u ! microscope1 b aphanitic rocks may (t5 be approximately classifi$ by comp>ison ) simil> rocks already accurately det]m9$4 ,to facilitate ?is me?od ( *emical analysis by measur+ ! m9]als1 ! *emical composition ( c]ta9 common rock-mak+ m9]als is express$ 9 proportional p>ts & tabulat$1 & is us$ some:at z molecul> weight is 9 ord9>y *emical analysis4 ,c]ta9 ( ^! are select$ z /&>d m9]als1 ! selection be+ su* t ! /&>d m9]als embrace all ! ess5tial elem5ts t ent] into ! composition ( rocks4 ,all o!r m9]als are conv]t$ into _! *emical equival5ts 9 t]ms ( ^! /&>d m9]als by ! use ( ! tables4 ,all ! m9]al con/itu5ts be+ ?us r$uc$ to /&>d m9]als1 ! classification is built up sy/ematically on ^! /&>d 7or /&>diz$7 m9]als4 ,a new sy/em ( names is requir$1 & ^! h be5 v skillfully =m$ by select+ significant lett]s f ! names ( ! lead+ m9]als or f words signify+ _! prepond]ance1 s t %ort t]ms :i* c>ry _! mean+ 9 _! =ms1 are secur$1 & ?is has be5 done s t ^! are usually euphoni\s1 h[ev] /range !y may seem to our preoccupi$ s5ses4 ,= example1 m9]als compos$ *iefly ( silica & alum9a are call$ salic2 ^? ( ferromagnesian m9]als1 femic2 ^? ( alum9\s ferromagnesian m9]als1 alf]ric1 etc4 ,:5 9 a comb9ation ( salic & femic m9]als1 ! salic are extremely abundant1 ! rock is p]salic2 if notably dm9ant1 dsalic2 if ! salic & femic m9]als are ne>ly equal1 salfemic2 if ! femic are dm9ant1 d(emic2 if extremely abundant1 p]femic1 & s on1 ! sy/em be+ mnemonic4 ,?is me?od ( d]iv+ names is applicable only to a portion ( ! necess>y divisions4 ,= ! re/1 a s]ies ( roots d]iv$ f geographic names1 ) a sy/em ( t]m9ations1 has be5 employ$4 ,all /&>d m9]als are divid$ into two gr\ps ( prim>y importance3 "o ( m9]als *>act]iz$ by alum9a1 z ! feldsp>s1--or?oclase1 albite1 anor?ite1--leucite1 nephelite1 sodalite1 noselite1 & corundum1 to :i* are add$ ! closely associat$ m9]als1 qu>tz & zircon4 ,?is is call$ ! salic gr\p4 ,! second gr\p conta9s m9]als *>act]iz$ by iron & magnesia ) no alum9a1 z hyp]/h5e 7en/atite71 acmite1 oliv9e1 magnetite1 hematite1 & ilm5ite1 to :i* are add$ ! closely associat$ m9]als1 titanite1 p](skite1 rutile1 apatite1 & all o!r rock-mak+ m9]als except ^? conta9+ alum9a toge!r ) iron & magnesia4 ,! second gr\p is call$ femic4 ,alum9\s f]romagnesian m9]als1 su* z hornbl5de1 augite1 mica1 etc42 are call$ alf]ric1 & are n class$ z /&>d m9]als1 because _! complexity ( composition makes x bett] to treat !m z ?\gh made up ( ! simpl] m9]als ( ! /&>d li/4 ,! composition ( all igne\s rocks c be express$ 9 t]ms ( ! relative proportions ( ! two gr\ps ( ! /&>d m9]als1 salic & femic4 ,by subdivid+ ^! gr\ps successively on a m9]al & *emical basis1 a s]ies ( classificatory divisions ( great] & great] precision has be5 =m$4 ,9 ea* /age ( ! s]ies1 two factors only are comp>$1 & a simple set ( ratios has be5 select$ to limit ! divisions4 ,assum+ ! possibility ( a cont9u\s range ( v>iable mixtures ( ! two factors 7,a & ,b7 f an extreme compos$ :olly ( "o 7,a71 & an extreme compos$ :olly ( ! o!r 7,b71 five ideal cases h be5 *os5 z types or c5t]po9ts ab\t :i* v>iation 9 mixture may take place4 ,^! are3 ,a #a ,a #c ,a #a ,a #a ,a #j ------ --1 ------ --1 ------ --1 ------ --1 ------ --4 ,b #j ,b #a ,b #a ,b #c ,b #a ,division l9es half-way betwe5 ^! po9ts occur z ! foll[+ ratios3 ,a #g ,a #g #e ,a #e #c ,a #c #a ,a #a 7#a7 ------ --1 7#b7 ------ -- --1 7#c7 ------ -- --1 7#d7 ------ -- --1 7#e7 ------ --4 ,b #a ,b #a #c ,b #c #e ,b #e #g ,b #g ,^! ratios are us$ ?r\gh\t ! sy/em4 ,9 7#a7 ,a is extreme2 9 7#e7 ,b is extreme2 9 7#b7 ,a dom9ates ov] ,b2 9 7#d7 ,b dom9ates ov] ,a2 9 7#c7 ,a & ,b are equal or ne>ly equal4 ,all igne\s rocks are gr\p$ 9 five 7#e7 prim>y divisions call$ ,classes on a basis ( ! proportions ( ! salic & femic m9]als1 ?us3 ,class ,i4 ,sal #g ------ --1 extremely ri* 9 salic m9]als1 call$ p]salane4 ,fem #g ,,ii4 ,sal #g #e ------ -- --1 ) dom9ant salic m9]als1 call$ dosalane4 ,fem #a #c ,,iii4 ,sal #e #c ------ -- --1 salic & femic m9]als1 equal or ne>ly equal1 ,fem #c #e call$ salfemane4 ,,iv4 ,sal #c #a ------ -- --1 ) dom9ant femic m9]als1 call$ d(emane4 ,fem #e #g ,v4 ,sal #a ------ --1 extremely ri* 9 femic m9]als1 call$ p]femane4 ,fem #g ,ea* ( ^! classes is divid$ into two subclasses accord+ to ! proportions ( two subgr\ps ( ! prepond]ant gr\p ( /&>d m9]als4 ,( salic m9]als "o subgr\p includes qu>tz1 feldsp>s1 & ! feldspa?oids2 ! o!r includes corundum & zircon4 ,( femic m9]als "o subgr\p includes ! silicates ) magnetite1 ilm5ite1 hematite1 & rutile2 ! o!r conta9s apatite & ! rema9+ m9]als ( ?is gr\p4 ,mo/ kn[n igne\s rocks fall into ! fir/ subclass ( ea* class4 ,! classes are fur!r divid$ into ord]s accord+ to ! proportions ( c]ta9 m9]als 9 ! prepond]ant subgr\ps4 ,?us ,classes ,i1 ,,ii1 & ,,iii are ea* divid$ into n9e ord]s on a basis ( ! proportions ( qu>tz & ! feldsp>s1 & ( ! feldsp>s & ! feldspa?oids1 qu>tz & feldspa?oids n occurr+ toge!r4 ,! ord]s may be describ$ 9 ! same t]ms = ea* ( ! fir/ ?ree classes z foll[s3 ,ord] ,i4 ,q #g -- --1 extremely ri* 9 qu>tz1 p]qu>ic4 ,f #a ,,ii4 ,q #g #e -- -- --1 qu>tz dom9ant ov] feldsp>1 doqu>ic4 ,f #a #c ,,iii4 ,q #e #c -- -- --1 qu>tz & feldsp> equal or ne>ly equal1 qu>felic4 ,f #c #e ,,iv4 ,q #c #a -- -- --1 feldsp> dom9ant ov] qu>tz1 qu>d(elic4 ,f #e #g ,v4 ,q or ,l #a ------------ --1 extremely ri* 9 feldsp>1 p]felic4 ,f #g ,,vi4 ,l #c #a -- -- --1 feldsp> dom9ant ov] feldspa?oids 7l5ads71 l5d(elic4 ,f #e #g ,,vii4 ,l #e #c -- -- --1 feldsp> & l5ads equal or ne>ly equal1 l5felic4 ,f #c #e ,,viii4 ,l #g #e -- -- --1 l5ads dom9ant ov] feldsp>s1 dol5ic4 ,f #a #c ,,ix4 ,l #g -- --1 extremely ri* 9 l5ads1 p]l5ic4 ,f #a ,9 classes ,,iv & ,v ! prepond]ant m9]als are femic1 & 9 subclass #a !y are silicates1 titanates1 & f]rates1 ) hematite & rutile4 ,^! are subdivid$ z foll[s3 ,silicates--pyrox5es & oliv9e ) ak]manite 9 "o subgr\p2 ! o!r m9]als1 magnetite1 hematite1 ilm5ite1 titanite1 p](skite1 rutile1 9 ! second subgr\p4 ,?is fir/ gr\p is call$ polic1 mnemonic ( pyrox5e & oliv9e2 ! second gr\p is call$ mitic1 mnemonic ( magnetite1 ilm5ite1 titanite4 ,!re are five ord]s 9 ea* ( ^! classes1 z foll[s3 ,ord] ,i4 ,,po #g ---- --1 extremely ri* 9 pyrox5e or oliv9e1 p]polic4 ,m #a ,,ii4 ,,po #g #e ---- -- --1 dom9ant pyrox5e or oliv9e1 dopolic4 ,m #a #c ,,iii4 ,,po #e #c ---- -- --1 pyrox5e or oliv9e1 equal or ne>ly equal to ! mitic ,m #c #e m9]als1 polmitic4 ,,iv4 ,,po #c #a ---- -- --1 dom9ant mitic m9]als1 domitic4 ,m #e #g ,v4 ,,po #a ---- --1 extremely ri* 9 mitic m9]als1 p]mitic4 ,m #g ,9 ! fir/ ?ree ord]s a di/9ction betwe5 pyrox5e & oliv9e is recogniz$ by sections1 five 9 numb]3 ,section #a4 ,p #g -- --1 extremely ri* 9 pyrox5e1 p]pyric4 ,o #a #b4 ,p #g #e -- -- --1 dom9ant pyrox5e1 dopyric4 ,o #a #c #c4 ,p #e #c -- -- --1 pyrox5e & oliv9e1 equal or ne>ly equal1 pyrolic4 ,o #c #e #d4 ,p #c #a -- -- --1 dom9ant oliv9e1 domolic4 ,o #e #g #e4 ,p #a -- --1 extremely ri* 9 oliv9e1 p]olic4 ,o #g ,9 ! la/ two ord]s a di/9ction betwe5 ! prepond]ant mitic m9]als is recogniz$ by subord]s1 five 9 numb]4 ,! m9]als conta9+ ,fe,o are comp>$ ) ^? conta9+ ,ti,o4 ,! =m]1 magnetite & hematite1 are call$ hemic1 mnemonic ( hematite2 ! latt] subgr\p1 titanite1 ilm5ite1 p](skite1 rutile1 are call$ tilic1 mnemonic ( titanite & ilm5ite4 ,( ord]s #d & #e1 !re are ,subord] #a4 ,h #g -- --1 hemic m9]als extreme1 p]hemic4 ,t #a #b4 ,h #g #e -- -- --1 dom9ant hemic m9]als1 dohemic4 ,t #a #c #c4 ,h #e #c -- -- --1 hemic & tilic m9]als equal or ne>ly equal1 ,t #c #e tilhemic4 #d4 ,h #c #a -- -- --1 dom9ant tilic m9]als1 dotilic4 ,t #e #g #e4 ,h #a -- --1 tilic m9]als extreme1 p]tilic4 ,t #g ,fur!r subdivision1 produc+ rangs & subrangs1 is made on ! "* ( ! *emical bases 9 ! /&>d m9]als us$ 9 =m+ ord]s & is express$ 9 t]ms ( ! molecul> proportions ( c]ta9 oxides4 ,= ! salic m9]als1 =m+ ord]s 9 ! fir/ ?ree classes1 ! bases are alkalies--,k,o & ,na,o--& lime1 ,ca,o4 ,= ! femic m9]als1 =m+ ord]s 9 ! la/ two classes1 ! bases are ,mg,o1 ,fe,o1 ,ca,o & alkalies1 ,k,o1 ,na,o4 ,9 classes ,i1 ,,ii1 & ,,iii rangs are =m$ by comp>+ salic alkalies1 ,k,o ,na,o1 ) salic lime1 ,ca,o2 & subrangs are =m$ by comp>+ ,k,o ) ,na,o4 ,rang #a4 ,k,o ,na,o #g ---------------------- --1 alkalies extreme1 p]alkalic4 ,ca,o #a #b4 #g #e -- --1 alkalies dom9ant1 domalkalic4 #a #c #c4 #e #c -- --1 alkalies & lime equal or ne>ly s1 #c #e alkalicalcic4 #d4 #c #a -- --1 lime dom9ant1 docalcic4 #e #g #e4 #a --1 lime extreme1 p]calcic4 #g ,subrang #a4 ,k,o #g -------- --1 pota% extreme1 p]potassic4 ,na,o #a #b4 #g #e -- --1 pota% dom9ant1 dopotassic4 #a #c #c4 #e #c -- --1 pota% & soda equal1 sodipotassic4 #c #e #d4 #c #a -- --1 soda dom9ant1 dosodic4 #e #g #e4 #a --1 soda extreme1 p]sodic4 #g ,9 classes ,,iv & ,v rangs are =m$ by comp>+ femic ,mg,o ,fe,o ,ca,o ) femic alkalies ,k,o ,na,o4 ,m9]als conta9+ magnesia1 iron1 & lime are call$ mirlic4 ,rang #a4 ,mg,o ,fe,o ,ca,o #g -------------------------------- --1 extremely mirlic1 p]mirlic4 ,k,o ,na,o #a #b4 #g #e -- --1 dom9antly mirlic1 domirlic4 #a #c #c4 #e #c -- --1 equally mirlic & alkalic1 alkalimirlic4 #c #e #d4 #c #a -- --1 dom9antly alkalic1 domalkalic4 #e #g #e4 #a --1 extremely alkalic1 p]alkalic4 #g ,sections ( rangs di/+ui% betwe5 ,mg,o ,fe,o & ,ca,o4 ,m9]als ) ,mg,o ,fe,o are call$ miric4 ,section #a4 ,mg,o ,fe,o #g ------------------ --1 extremely miric1 p]miric4 ,ca,o #a #b4 #g #e -- --1 dom9antly miric1 domiric4 #a #c #c4 #e #c -- --1 equally miric & calcic1 calcimiric4 #c #e #d4 #c #a -- --1 dom9antly calcic1 docalcic4 #e #g #e4 #a --1 extremely calcic1 p]calcic4 #g ,subrangs di/+ui% betwe5 ,mg,o & ,fe,o1 ?us3 ,subrang #a4 ,mg,o #g ------ --1 extremely magnesic1 p]magnesic4 ,fe,o #a #b4 #g #e -- --1 dom9antly magnesic1 domagnesic4 #a #c #c4 #e #c -- --1 equally magnesic & f]r\s1 magnesif]r\s4 #c #e #d4 #c #a -- --1 dom9antly f]r\s1 d(]r\s4 #e #g #e4 #a --1 extremely f]r\s1 p]f]r\s4 #g ,f9ally a recognition ( ! "* ( ! subord9ate /&>d m9]als leads to fur!r subdivisions kn[n z grads & subgrads4 ,!y only occur 9 classes ,,ii1 ,,iii1 & ,,iv1 because ^! are ! only ones 9 :i* ! subord9ate m9]als are 9 notable am\nts4 ,grads are =m$ 9 a mann] simil> to t employ$ to produce ord]s4 ,?us grads 9 classes ,,ii & ,,iii correspond to ord]s 9 class ,,iv & ! rev]se4 ,subgrads are ! same 9 =m z rangs :5 ! diff]5ce 9 ! treatm5t ( salic & femic m9]als is borne 9 m9d4 ,! names giv5 to ^! divisions1 :i* 9 fact recognize only ! "* ( ! magma1 are d]iv$ f geographical localities & embrace _m ( ^? already 9 use1 except t ! names ( ord]s are tak5 f c\ntries or nations4 ,specific t]m9ations indicate ! place 9 ! s]ies ( divisions3 ane = class1 "o = subclass4 are = ord]1 ore = subord]4 ase = rang1 ose = subrang4 ate = grad1 ote = subgrad4 ,?is may be illu/rat$ z foll[s3 ,class ,i4 p]salane1 all rocks extremely salic4 ,ord] #d4 britann>e1 feldsp> dom9ant ov] qu>tz1 qu>d(elic4 ,_m rocks ( granitic composition :e!r cry/all9e or glassy4 ,rang #a4 lip>ase1 p]alkalic1 rocks 9 :i* ! pot5tial feldsp>s are extremely alkalic1 or?oclase1 or albite4 ,subrang #b4 ,omeose1 dopotassic1 rocks 9 :i* ! extremely alkali feldsp>s are dom9antly potassic1 or?oclase1 ) subord9ate albite4 ,examples ( omeose are3 granite f ,omeo1 ,victoria1 ,au/ralia1 & rhyolite f ,silv] ,cliff1 ,colorado4 ,! pres5ce ( di/9ctive m9]als n indicat$ 9 ! /&>d m9]al composition ( norm is express$ by qualify+ ! magmatic "n by ! "n ( ! di/9ctive m9]al2 z1 a hornbl5de-monzonose4 ,! precise texture ( ! rock is express$ by qualify+ ! magmatic "n by a textural adjective2 z1 a grano-monzonose1 a vitro-monzonose1 a phyro-monzonose1 etc4 ,,ref]5ce ,,li/ ,,( ,,! ,,m ,,common ,,m9]als4 ,act9olite--a magnesium-calcium-iron amphibole 7q4v472 commonly bright gre5 to grayi% gre52 cry/als usually sl5d] or fibr\s4 ,agate--a b&$ or v>iegat$ *alc$ony 7qu>tz1 q4v474 ,alaba/]--a f9e-gra9$ v>iety ( gypsum 7q4v471 ei!r :ite or delicately color$4 ,albite--a soda feldsp> 7q4v471 an alum9um-sodium silicate2 ,h4 #e-f2 cleavage p]fect 9 two planes2 lu/] vitre\s or pe>ly :ite2 occasionally blui% gray1 r$di%1 gre5i%2 sometimes opalesc5t4 ,ame?y/--a v>iety ( qu>tz ( purple or blui%-violet color1 due probably to manganese4 ,amphibole--! type ( an important gr\p ( rock-=m+ m9]als kn[n z ! amphibole or hornbl5de gr\p2 a f]romagnesian silicate1 monocl9ic1 ,h4 #e-f2 lu/] vitre\s to pe>ly2 fibr\s v>ieties (t5 silky2 black1 rang+ ?r\gh v>i\s %ades ( gre5 to light colors2 embraces ! magnesium-calcium v>ieties1 tremolite & nephrite2 ! magnesium-calcium-iron v>iety act9olite2 ! alum9\s-magnesium-iron-calcium v>iety hornbl5de1 & o!rs4 ,analcite--analc9e1 "o ( ! zeolites2 a hydr\s alum9um-sodium silicate2 lu/] vitre\s1 colorless1 :ite2 occasionally grayi%1 gre5i%1 yell[i%1 r$di%1 transp>5t to opaque4 ,&es9e--a plagioclase feldsp> 7q4v472 a sodium-calcium-alum9um silicate1 int]m$iate 9 composition betwe5 albite & anor?ite2 ,h4 #e-f2 :ite1 gray1 grayi%1 yell[i%1 fle% r$2 lu/] subvitre\s1 incl9+ to pe>ly4 ,&alusite--an alum9um silicate2 lu/] vitre\s2 :iti%1 rose r$1 fle% r$1 v>iety pe>ly gray1 r$di% br[n1 olive-gre52 ,h4 #g4e1 infusible2 impurities sometimes s arrang$ 9 ! int]ior z to exhibit a color$1 cross$1 or tesselat$ appe>ance 9 cross-section 7*ia/olite74 ,anhydrite--a calcium sulphate2 ,h4 #c-c4e2 lu/] pe>ly to vitre\s2 :ite1 sometimes blui% or r$di%2 diff]s f gypsum 9 abs5ce ( wat] & 9 its great] h>dness4 ,anor?ite--a plagioclase feldsp> 7q4v472 a calcium-alum9um silicate2 v>ies mu* by impurities & admixtures2 ,h4 #f-f4e2 pe>ly or vitre\s lu/]2 :ite1 grayi%1 r$di%4 ,an?racite--h>d coal2 hydroc>bon ) impurities2 suppos$ to be d]iv$ f bitum9\s coal by metamorphism4 ,antimony--a native metal1 t9-:ite1 brittle2 r r>e 9 native =m4 ,apatite--ess5tially calcium phosphate ) *lor9e or fluor9e2 hexagonal2 ,h4 #e2 lu/] vitre\s or subres9\s2 colors usually gre5i% to blui%1 *>act]iz$ by a hexagonal =m4 ,aragonite--a calcium c>bonate2 diff]s f calcite 9 cleavage1 & 9 be+ or?orhombic2 ,h4 #c4e-d2 lu/] vitre\s or res9\s2 :ite1 also gray1 yell[1 gre51 & violet4 ,asphaltum--asphalt2 m9]al pit*1 bitum52 a natural mixture ( diff]5t hydroc>bons2 odor bitum9\s2 melts at #ij to #ajj degrees ,c42 burns ) a bright flame2 graduates into m9]al t>s & ?r\gh ^! into petroleum2 probably ! residue ( ! latt]4 ,augite--"o ( ! pyrox5es 7q4v472 an alum9um-calcium-magnesium-iron silicate2 ,h4 #e-f2 monocl9ic1 cry/als usually ?ick & /\t2 sometimes lamell>2 also granul>2 black1 gre5i% black1 deep gre52 an important rock-=m+ m9]al4 ,beauxite--ess5tially hydrat$ alum9a2 occurs 9 concretion>y gra9s ( clay-l =m1 :iti% to br[n2 valuable z a s\rce ( alum9um4 ,b]yl--a b]yllium-alum9um silicate2 hexagonal2 prismatic2 ,h4 #h2 lu/] vitre\s or res9\s2 m>l-gre51 pale pass+ into :iti%2 closely resembles apatite1 b di/+ui%$ by sup]ior h>dness & 9 composition4 ,b>ite--b>ites1 heavy-sp>1 b>ium sulphate2 or?orhombic1 ,h4 #c-c4e2 lu/] vitre\s to res9\s1 sometimes pe>ly2 :ite1 incl9+ to yell[1 gray1 blue1 r$1 or br[n2 v heavy1 sp4 gr4 #d4c-d4g4 ,biotite--black mica1 a pota%-alum9um-magnesium-iron silicate2 monocl9ic2 easy basal cleavage into ?9 lam92 sometimes occurs z a massive aggregation ( cleavable scales2 ,h4 #b4e-c2 lu/] spl5d5t on cleavage surface2 black to d>k gre52 cleavage surfaces smoo? & %9+2 a v common con/itu5t ( cry/all9e rocks4 ,bitum5--! same z asphaltum 7q4v474 ,bismu?--a metal ( :iti% color & r brittle nature2 occurr+ occasionally native1 usually z an ore4 ,bronzite--a v>iety ( en/atite 7q4v472 grayi% gre5 to olive-gre5 & br[n ) lu/] on cleavage surface (t5 adamant9e1 pe>ly or bronze-l & submetallic4 ,calcite--calcsp>2 calcium c>bonate2 rhomboh$ral1 p]fect rhomboh$ral cleavage2 (t5 tak+ ! =ms kn[n z dogtoo? sp>1 nail-head sp>2 frequ5tly /alactitic & /alagmitic2 ,h4 #b4e-c4e2 lu/] vitre\s2 :ite1 occasionally pale %ades ( gray1 r$1 gre51 blue1 violet1 yell[1 br[n2 /rong d\ble refraction2 embraces v>iety call$ ,icel& sp>2 a v common m9]al2 ! ess5tial basis ( lime/one4 ,cassit]ite--t9 /one2 an oxide ( t92 tetragonal2 lu/] adamant9e1 usually spl5d5t2 br[n or black1 sometimes r$1 gray1 :ite1 or yell[2 an important s\rce ( t94 ,catl9ite--ess5tially a h>d5$ r$ clay1 r a rock ?an a m9]al2 mu* priz$ by ,indians = pipes4 ,*alc$ony--a cryptocry/all9e v>iety ( qu>tz hav+ a wax-l lu/]1 ei!r transp>5t or transluc5t2 :ite1 grayi%1 pale br[n to d>k br[n1 black1 sometimes delicate blue1 occasionally o!r %ades2 frequ5tly occurs z ! l9+ or fill+ ( cavities1 tak+ on a botryoidal or mamill>y =m4 ,*ia/olite--&alusite 7q4v474 ,*lorite--! type ( an important gr\p ( second>y m9]als usually *>act]iz$ by a gre5 color1 s(tness & smoo?ness or unctu\sness ( feel+2 !y are usually alum9um-magnesium-iron silicates1 ) *emically comb9$ wat]2 d]iv$ f sev]al o!r species1 z pyrox5e1 amphibole1 biotite1 g>net1 etc42 embraces a numb] ( species1 among :i* are cl9o*lore1 p5n9ite1 pro*lorite1 & delessite4 ,*romite--*romic iron2 ess5tially an iron *romate2 isometric2 lu/] submetallic2 iron black to br[ni% black2 opaque2 sometimes magnetic2 resembles magnetite4 ,*rysolite--oliv9e2 ess5tially a magnesium-iron silicate2 or?orhombic2 ,h4 #f-g2 lu/] vitre\s2 gre51 commonly olive-gre51 sometimes yell[1 br[ni%1 grayi% gre52 highly infusible2 a common con/itu5t ( c]ta9 basic igne\s rocks2 ! "n oliv9e is m commonly us$ by geologi/s4 ,*rysotile--a delicately fibr\s v>iety ( s]p5t9e 7q4v474 ,corundum--alum9a2 an oxide ( alum9um2 ,h4 #i2 rhomboh$ral2 l>ge cry/als usually r\gh2 lu/] vitre\s2 color blue1 r$1 yell[1 gray1 & ne>ly :ite2 pur] =ms ( f9e colors are sapphires2 ! r$ v>iety is ruby1 ! yell[1 ori5tal topaz1 ! gre51 em]ald1 & ! purple1 ame?y/2 d>k colors1 ) iron oxide1 em]y4 ,delessite--a f]rug9\s *lorite1 usually olive-gre5 or blacki% gre52 occurr+ commonly 9 ! cavities ( amygdaloids4 ,diallage--a v>iety ( pyrox5e 7q4v472 ,h4 #d2 *>act]iz$ by ?9 foli2 usually grayi% gre5 to grass-gre51 or deep gre52 lu/] on cleavage surface pe>ly1 sometimes metalloid or brassy2 an ess5tial m9]al 9 ! gabbros1 z sometimes def9$4 ,elolite--a v>iety ( nephelite 7q4v472 occurr+ 9 l>ge co>se cry/als or massive1 ) greasy lu/]1 f :i* ! "n is d]iv$2 a *>act]i/ic con/itu5t ( elolite sy5ite4 ,en/atite--"o ( ! pyrox5es2 ess5tially a magnesium silicate2 or?orhombic2 ,h4 #e4e2 lu/] a little pe>ly on cleavage surface2 metalloidal 9 ! bronze v>iety 7bronzite72 grayi% :ite1 yell[i% :ite1 gre5i% :ite to olive-gre5 & br[n2 v infusible2 a common m9]al 9 c]ta9 basic cry/all9e rocks4 ,epidote--a complex alum9um-calcium-iron silicate ( v>y+ composition2 monocl9ic2 ,h4 #f-g2 lu/] vitre\s1 pe>ly1 or res9\s2 color usually pi/a*io-gre51 or yell[i% gre5 to br[ni% gre52 c usually be detect$ by its peculi> pi/a*io hue1 :i* is seldom f\nd 9 o!r m9]als2 common 9 _m cry/all9e rocks1 usually z a second>y product4 ,feldsp>--a gr\p ( m9]als ( ! fir/ importance 9 rock =mation1 embrac+ or?oclase1 microcl9e1 albite1 oligoclase1 &es9e1 labradorite1 anor?ite1 & num]\s v>iations2 alum9um silicates1 ) ei!r potassium1 sodium1 or calcium or two or m ( ^!2 cry/allizes 9 bo? ! monocl9ic & tricl9ic sy/ems2 possesses v di/9ct cleavage 9 two directions2 ,h4 #f-f4e2 range 9 color f :ite ?r\gh pale yell[1 r$1 or gre51 & occasionally d>k2 tricl9ic feldsp>s frequ5tly call$ plagioclase 7see individual feldsp>s74 ,fluorite--fluorsp>2 calcium fluoride2 isometric1 usually cubic2 ,h4 #d2 lu/] vitre\s1 sometimes spl5d5t2 :ite1 yell[1 gre51 rose1 crimson r$1 violet1 sky-blue1 & br[n2 yell[1 gre5i%1 & violet mo/ common2 occurs usually 9 ve9s or cavities 9 beautiful cry/all9e =m4 ,gal5ite--gal5a2 lead sulphide2 isometric1 usually cubic2 p]fect cubic cleavage2 lu/] metallic2 lead-gray2 a common ore ( lead2 occurs 9 ve9s & lay]s1 also z l9+s ( cavities4 ,g>net--a complex silicate ( v>y+ composition1 embrac+ alum9um1 calcium1 magnesium1 *romium1 iron1 & manganese1 b usually only two or ?ree ( ^! are pres5t 9 abundance1 & ! v>ieties are *>act]iz$ by ! lead+ con/itu5t2 isometric1 usually 9 dodecah$rons or trapezoh$rons2 ,h4 #f4e-g4e2 lu/] vitre\s to res9\s2 commonly r$ or br[n1 sometimes yell[1 :ite to blue1 gre5 or black2 common 9 mica s*i/1 gneiss1 hornbl5de s*i/2 also 9 granite1 sy5ite1 & metamorphos$ lime/one4 ,geys]ite--a concretion>y deposit ( silica 9 ! opal condition2 =m$ ab\t geys]s2 :ite or grayi%4 ,glauconite--gre5-s&1 a hydr\s potassium-iron silicate usually impure1 amorph\s1 or e>?y2 dull olive-gre5 or blacki%1 yell[i%1 or grayi% gre52 opaque1 commonly occurs z gra9s or small aggregations4 ,graphite--plumbago1 black lead2 a =m ( c>bon1 usually impure2 rhomboh$ral1 b r>ely appe>+ z a cry/al2 m (t5 z ?9 lam9 ( greasy feel2 yields a black adhesive p[d]2 h5ce its common use = lead p5cils2 occurs 9 granite1 gneiss1 mica s*i/1 cry/all9e lime/one2 sometimes results f alt]ation ( coal by heat2 occasionally occurs 9 basaltic rocks & meteorites4 ,gypsum--a hydr\s calcium sulphate2 monocl9ic2 p]fect cleavage into smoo? poli%$ plates2 occurs 9 a v>iety ( =ms1 includ+ fibr\s & granul>2 ,h4 #a4e-b2 lu/] pe>ly & %9y2 :ite1 sometimes gray1 fle%-r$1 yell[i%1 & blue2 impure v>ieties d>k2 cry/alliz$ v>ieties include sel5ite1 sat9sp>1 alaba/]1 etc42 easily recogniz$ by its s(tness & want ( eff]vesc5ce ) acids2 occurs 9 b$s2 calc9$ & gr\nd con/itutes pla/] ( ,p>is4 ,haynite--a complex sodium-alum9um silicate & calcium sulphate2 cry/als dodecah$rons2 lu/] vitre\s or some:at greasy2 bright blue1 sky-blue1 or gre5i% blue1 or gre52 occurs 9 c]ta9 igne\s rocks1 commonly associat$ ) nephelite & leucite4 ,hematite--f]ric oxide1 ,fe,o1 iron-sesquioxide2 rhomboh$ral1 m commonly column>1 granul>1 botryoidal1 or /alactitic2 lu/] metallic1 sometimes e>?y2 iron-black1 d>k /eel-gray1 r$ :5 e>?y2 gives r$ /reak or p[d]2 a lead+ iron ore1 #gj p]c5t4 metallic iron :5 pure2 ! *ief s\rce ( ! r$ color ( soils & rocks g5]ally4 ,hornbl5de--an amphibole2 "n sometimes us$ z a synonym = amphibole2 sometimes to designate a v>iety "u amphibole 7q4v474 ,hyalite--a v>iety ( silica 9 ! opal condition2 cle> & colorless l glass1 consi/+ ( globul> concretions or cru/s4 ,hyp]/h5e--"o ( ! pyrox5es2 a f]romagnesian silicate2 or?orhombic2 ,h4 #e-f2 lu/] some:at pe>ly on cleavage2 surface (t5 iridesc5t2 d>k br[ni% gre51 grayi%1 or gre5i% black & br[n2 a frequ5t con/itu5t ( cry/all9e rocks4 ,icel& sp>--a =m ( transp>5t calcite 7q4v474 ,ilm5ite--m5accanite2 a titanium iron oxide2 rhomboh$ral2 resembles hematite2 lu/] submetallic2 iron-black2 p[d] black or br[ni% r$2 occurs frequ5tly 9 cry/all9e rocks associat$ ) magnetite4 ,iron pyrites--pyrite 7q4v474 ,kaol9--kaol9ite2 ess5tially a hydr\s alum9um silicate2 usually 9 clay-l or e>?y =m2 :ite or grayi% :ite2 (t5 t+$ ) impurities2 commonly arises f decomposition ( alum9\s silicates1 especially ! feldsp>s2 basis ( pott]y & *9a4 ,labradorite--a plagioclase feldsp>2 ess5tially an alum9um-calcium-sodium silicate2 composition int]m$iate betwe5 t ( albite & anor?ite2 tricl9ic2 ,h4 #f2 lu/] pe>ly or vitre\s1 gray1 br[n1 or gre5i%2 sometimes colorless or :ite2 frequ5tly %[s play ( colors2 important con/itu5t ( v>i\s cry/all9e rocks1 especially ( ! basic class2 usually associat$ ) a pyrox5e or amphibole4 ,lepidolite--li?ia mica2 ess5tially l muscovite 7q4v47 except t pota% is replac$ by li?ia4 ,leucite--ess5tially an alum9um-potassium silicate1 alli$ to ! feldsp>s2 ,h4 #e-f2 lu/] vitre\s1 :ite1 a%-gray1 or smoke-gray2 occurs 9 c]ta9 volcanic rocks1 p>ticul>ly lavas ( ,vesuvius4 ,limonite--br[n hematite1 o*]2--a hydr\s iron oxide2 commonly e>?y2 also concretion>y1 /alactitic1 botryoidal1 & mamill>y1 ) fibr\s /ructure2 ,h4 #e-e4e2 lu/] silky1 sometimes submetallic1 b commonly dull & e>?y2 br[n1 o*]\s yell[2 /reak & p[d] yell[i% br[n2 con/itutes o*]1 bog-ore1 iron/one1 etc42 is ! *ief s\rce ( ! yell[ color ( soils & rocks2 arises f ! alt]ation ( o!r iron ores4 ,magnesite--magnesium c>bonate2 rhomboh$ral2 :ite1 yell[i%1 grayi% :ite to br[n2 fibr\s1 e>?y1 or massive2 f\nd 9 alt]$ magnesium rocks4 ,magnetite--magnetic iron ore2 iron oxide1 ,fe,o2 octah$ral or dodecah$ral2 /rongly magnetic2 ,h4 #e4e-f4e2 ab\nds 9 igne\s & metamorphic rocks4 ,m>casite--:ite iron pyrites2 iron sulphide2 same composition z pyrite1 :i* x closely resembles2 ,h4 #f-f4e2 lu/] metallic1 pale gray1 bronze1 or yell[2 prone to decomposition2 dissem9at$ ?r\gh v>i\s rocks1 p>ticul>ly pla/ic clays conta9+ organic matt]4 ,m>tite--iron sesquioxide2 orig9ally magnetite1 :i* by oxidation has assum$ ! composition ( hematite4 ,mica--! type ( an important gr\p ( rock-=m+ m9]als well kn[n = _! p]fect cleavage into ?9 ela/ic lam92 among ! lead+ v>ieties are ! common potassium mica 7muscovite71 ! sodium mica 7p>agonite71 ! li?ium mica 7lepidolite71 ! magnesium-iron mica 7biotite71 ! magnesium mica 7phlogopite71 & ! iron-pota% mica 7lepidomelane74 ,m5accanite--ilm5ite2 titanium iron ore 7q4v474 ,microcl9e--a tricl9ic feldsp>1 closely resembl+ or?oclase 9 appe>ance & hav+ ! same composition4 ,muscovite--common or pota% mica2 ess5tially an alum9um-potassium silicate2 ,h4 #b-b4e2 monocl9ic2 rem>kable = its basal cleavage2 splits easily into exce$+ly ?91 flexible1 ela/ic lam92 lu/] vitre\s1 m or less pe>ly or silky2 colorless or v>i\sly t+$ br[n1 gre51 or violet2 a common m9]al 9 cry/all9e rocks1 p>ticul>ly 9 ! granites or gneisses4 ,nephelite--nephel9e2 ess5tially an alum9um-sodium silicate ) pota%2 alli$ to ! soda-feldsp>s2 hexagonal2 usually 9 ?ick prisms2 ,h4 #e4e-f2 lu/] vitre\s to greasy1 :ite or yell[i%1 v>y+ to gre5i%1 blui%1 & r$2 occurs 9 volcanic rocks2 ! v>iety elolite *>act]izes ! elolite sy5ite4 ,nosite--nosean2 a complex sodium-alum9um silicate & sulphate1 l haynite1 b ) little calcium2 common 9 phonolites4 ,oligoclase--a plagioclase feldsp>2 ess5tially an alum9um-calcium-sodium silicate :i* may be reg>d$ z a mixture ( albite & a small am\nt ( anor?ite2 tricl9ic2 lu/] vitre\s1 pe>ly1 or waxy2 :iti% grad+ into gre5i% & r$di%2 ,h4 #f-g2 common 9 cry/all9e rocks4 ,or?oclase--a pota% feldsp>2 ess5tially a potassium-alum9um silicate2 v>y+ by ! replacem5t ( ! potassium by sodium & less frequ5tly by o!r sub/itutions2 monocl9ic2 occurr+ 9 di/9ct cry/als & also 9 cryptocry/all9e =ms2 cleavage planes p]fect ) pe>ly lu/] on cleavage surface2 :ite1 gray1 & fle%-r$1 occasionally v>y+ to gre5i% :ite & bright gre52 ,h4 #f-f4e2 difficultly fusible2 sanid9e a glassy v>iety2 felsite a cryptocry/all9e =m2 a v common m9]al1 especially 9 ! granites & gneisses4 ,oliv9e--*rysolite 7q4v474 ,omphacite--a v>iety ( pyrox5e ( grass-gre5 color & silky to fibr\s lu/]2 alli$ to diallage4 ,opal--silica ) a v>y+ am\nt ( wat]2 diff]s f qu>tz 9 a lack ( cry/allization & 9 l[] degree ( h>dness2 amorph\s1 massive2 sometimes r5i=m1 /alactitic1 or tub]\s2 also e>?y2 ,h4 #e4e-f4e2 lu/] vitre\s1 incl9+ to res9\s2 :ite1 yell[1 r$1 br[n1 gre51 gray1 blue1 g5]ally pale2 colors arise f admixtures2 sometimes play ( colors z 9 preci\s opal4 ,ozoc]ite--a native p>aff9e1 m9]al wax4 ,petroleum--naph?a2 a native m9]al oil2 a hydroc>bon1 commonly believ$ to arise f organic matt]1 bo? animal & vegetable1 b held by "s to be due to deep-seat$ *emical & !rmal action4 ,pictotite--a v>iety ( sp9el1 conta9+ *romium4 ,pisolite--a concretion>y v>iety ( calcite4 ,picrolite--a v>iety ( s]p5t9e4 ,pi$montite--a manganese epidote4 ,plagioclase--a g5]al t]m embrac+ ! tricl9ic feldsp>s ^: two cleavages are oblique to ea* o!r2 embrac+ albite1 oligoclase1 &es9e1 labradorite1 & anor?ite 7q4v474 ,plumbago--graphite 7q4v474 ,psilomelane--ess5tially a hydr\s manganese oxide occurr+ 9 massive1 botryoidal1 r5i=m1 & /alactitic =ms2 lu/] submetallic2 iron-black1 pass+ into d>k /eel-gray2 ,h4 #e-f2 ! common ore ( manganese4 ,pseudomorph--a false =m1 i4e41 hav+ ! =m ( "o m9]al & ! composition ( ano!r2 usually arises f ! replacem5t ( a m9]al1 p>ticle by p>ticle1 by a solution ( ano!r sub/ance1 leav+ ! orig9al =m un*ang$4 ,pyrite--iron pyrites1 fool's gold1 iron sulphide2 isometric2 commonly 9 cubes2 ,h4 #f-f4e2 lu/] metallic1 spl5d5t1 or gli/5+2 pale brass-yell[2 occurs widely dissem9at$ ?r\gh\t a l>ge class ( rocks2 usually h>d] & light] 9 color ?an copp] pyrites1 & deep] 9 color ?an m>casite1 :i* has ! same composition4 ,pyrox5e--! type ( a l>ge & important gr\p ( rock-=m+ f]romagnesian m9]als2 v>ies 9 composition & embraces a l>ge numb] ( v>ieties2 usually a magnesium-iron-calcium silicate2 cry/als usually ?ick & /\t1 b v>y+ greatly2 sometimes lamell> & fibr\s2 ,h4 #e-f2 lu/] vitre\s incl9+ to res9\s2 gre5 ( v>i\s %ades v]g+ t[>ds light colors1 occasionally m (t5 to br[ns & blacks2 among ! m9]als belong+ to ! pyrox5e gr\p are augite1 bronzite1 diallage1 diopside1 en/atite1 hyp]/h5e1 & o!rs4 ,qu>tz--cry/alliz$ silica2 rhomboh$ral2 cry/als commonly six-sid$ prisms capp$ by six-sid$ pyramids2 )\t cleavage2 ,h4 #g2 scrat*es glass2 usually transp>5t1 glassy1 colorless :5 pure1 %ad$ by impurities to yell[1 r$1 br[n1 gre51 blue1 & black2 v>ieties1 ame?y/1 purple1 or violet2 false topaz1 yell[1 rose-qu>tz1 smoky1 milky1 cat's eye1 opalesc5t2 av5tur9e1 spangl$ ) scales ( mica2 *alc$ony is a cryptocry/all9e v>iety2 c>nelian1 a r$ *alc$ony2 *rysoprase1 an apple-gre5 *alc$ony2 prase1 a leek-gre5 v>iety2 agate1 a v>iegat$ or b&$ *alc$ony2 moss-agate1 a *alc$ony conta9+ moss-l or d5dritic cry/allizations ( iron or manganese oxide2 onyx1 a *alc$ony 9 lay]s2 s>donyx1 l onyx 9 /ructure1 b includes lay]s ( s>d 7c>nelian72 jasp]1 an opaque-color$ qu>tz1 usually r$ or br[n2 fl9t1 an opaque impure *alc$ony2 *]t1 an ill-def9$ t]m appli$ to an impure fl9ty rock2 horn/one1 a transluc5t1 brittle1 fl9ty rock4 ,rutile--titanium oxide2 tetragonal1 cry/als commonly 9 prisms2 ,h4 #f-f4e2 lu/] metallic1 adamant9e2 r$di% br[n1 pass+ to r$2 sometimes yell[i%1 blui%1 violet1 & black2 occurs 9 cry/all9e rocks & is a common second>y product 9 ! =m ( microlites4 ,sanid9e--a glassy v>iety ( or?oclase feldsp>4 ,sat9sp>--a v>iety ( sel5ite or gypsum4 ,sel5ite--a di/9ctly cry/alliz$ transp>5t =m ( gypsum4 ,s]p5t9e--a hydr\s magnesium silicate2 usually 9 pseudomorph =ms2 also fibr\s1 granul>1 cryptocry/all9e1 & amorph\s2 ,h4 #b4e-d2 lu/] subres9\s to greasy1 pe>ly or e>?y1 res9\s or wax-l2 feel1 smoo? & some:at greasy2 leek-gre5 to blacki% gre5 & sisk9 gre5 v]g+ into br[ni% & o!r colors2 app>5tly d]iv$ mo/ commonly f *rysolite or oliv9e & also f o!r magnesian m9]als2 sometimes con/itutes ! bulk ( rock masses4 ,sid]ite--iron c>bonate2 rhomboh$ral2 ,h4 #c4e-d4e2 lu/] vitre\s1 m or less pe>ly1 a%-gray1 yell[i% or gre5i%1 also br[ni%2 occurs z ext5sive iron deposits & 9 cry/all9e rocks4 ,sm>agdite--a =m ( amphibole or hornbl5de 7q4v474 ,sph]osid]ite--a globul> =m ( sid]ite4 ,sp9el--a magnesium-alum9um oxide2 cry/als1 octah$rons2 r$ ( v>i\s %ades1 pass+ into o!r colors2 sp9el-ruby is a v>iety4 ,/aurolite--a complex hydr\s iron-magnesium-alum9um silicate2 or?orhombic2 dispos$ to cruci=m %apes2 occurs 9 s*i/s & gneisses4 ,/eatite--soap/one1 a v>iety ( talc 7q4v472 a hydr\s magnesium silicate4 ,sulphur--a well-kn[n elem5t occurr+ native 9 volcanic regions2 also =m$ by ! decomposition ( sulphides1 p>ticul>ly pyrites4 ,talc--a hydr\s magnesium silicate2 usually 9 foli2 granul> or fibr\s =ms2 also compact2 easy cleavage into ?9 flexible lam9a1 b n ela/ic2 feel greasy2 lu/] pe>ly on cleavage surface2 apple-gre5 to silv]y :ite2 ,h4 #a-b2 a second>y product f ! alt]ation ( magnesian m9]als2 di/+ui%$ by its s(t1 soapy feel1 soap/one be+ "o v>iety2 :iti% =m is kn[n z ,fr5* *alk4 ,titanite--calcium-titano-silicate2 monocl9ic2 lu/] adamant9e to res9\s2 br[n1 gray1 yell[1 gre51 & black2 ,h4 #e-e4e2 occurs 9 v>i\s cry/all9e rocks4 ,topaz--an alum9um silicate1 ) "p ( ! oxyg5 replac$ by fluor9e2 or?orhombic2 ,h4 #h2 lu/] vitre\s2 colorless1 /raw-yell[ v]g+ to v>i\s pale %ades1 grayi%1 gre5i%1 blui%1 & r$di%2 di/+ui%$ by its h>dness & infusibility2 occurs 9 cry/all9e rock4 ,tremolite--a calcium-magnesium amphibole2 a common con/itu5t ( c]ta9 cry/all9e rocks4 ,viridite--a g5]al t]m us$ = gre5 products ( rock alt]ation1 usually hydr\s silicates ( iron & magnesia2 ma9ly *lorite4 ,wad--bog manganese2 a v>iety ( psilomelane 7q4v474 ,zeolite--a gr\p ( m9]als d]iv$ f ! alt]ation ( v>i\s alum9\s silicates4 ,zircon--zirconium silicate2 ,h4 #g4e2 lu/] adamant9e2 pale yell[i%1 grayi%1 yell[i% gre51 br[ni% yell[1 & r$di% br[n2 infusible2 occurs *>act]i/ically 9 squ>e prismatic =ms2 f\nd 9 cry/all9e rocks & granul> lime/one4 ,,ref]5ce ,,li/ ,,( ,,! ,,m ,,common ,,rocks4#bjf ,adobe--a f9e silty or loamy deposit =m$ by g5tle wa% f slopes & subsequ5t lodgm5t on flats2 especially appli$ to silty accumulations 9 ! bas9s & on ! pla9s ( ! we/]n dry region4 ,agglom]ate--an aggregate ( irregul>1 angul>1 or subangul> blocks ( v>y+ sizes1 usually ( volcanic orig91 di/+ui%$ f conglom]ate 9 :i* ! con/itu5ts are r\nd$4 ,alluvium--s$im5t deposit$ by /reams4 ,amygdaloid--a vesicul> igne\s rock ^: cavities h become fill$ ) m9]als2 ! fill+s are call$ amygdules1 because sometimes almond-l 9 =m4 ,&esite--an aphanitic igne\s rock consi/+ ess5tially ( ! plagioclase feldsp> &es9e 7sometimes oligoclase7 & pyrox5e 7or "s relat$ f]romagnesian m9]al72 sometimes cellul>1 porphyritic1 or ev5 glassy2 usually ri* 9 feldsp> microlites4 ,anor?osite--a rock consi/+ ma9ly ( ! feldsp> labradorite4 ,aphanite--a rock ^: con/itu5ts are s m9ute z to be indi/+ui%able to ! nak$ eye2 r a condition ( v>i\s rocks ?an ( any specific rock4 ,aque\s rocks--a g5]al t]m appli$ to rocks deposit$ ?r\gh ! ag5cy ( wat]4 ,ar5ace\s rocks--ei!r ^? :i* are ma9ly s& or ^? 9 :i* s& is a notable accessory4 ,argillite--a clayey rock2 usually appli$ to h>d v>ieties only4 ,arkose--a s& or s&/one =m$ ( disaggregat$ granite or simil> rock 9 :i* a notable "p ( ! gra9s are feldsp> or o!r silicate2 s& :5 undef9$1 is und]/ood to be qu>tzose4 ,augitite--a rock ma9ly made up ( augite4 ,basalt--a d>k1 compact basic igne\s rock consi/+ ( a mass ( m9ute cry/als sometimes ) m or less glassy base1 (t5 conta9+ also visible cry/als2 compos$ ( plagioclase & pyrox5e1 ) oliv9e1 magnetite1 or titanif]\s iron z common accessories2 a basic lava 9 :i* ! cry/allization has tak5 place rapidly2 usually ri* 9 cry/allites or microlites2 graduates into dol]ite & basic &esite4 ,bitum9\s coal--common s(t coal1 int]m$iate betwe5 lignite & an?racite2 conta9s mu* bitum9\s matt]1 i4e41 hydroc>bons4 ,b[ld]s--r\nd$ masses ( rock1 p>ticul>ly ^? t h be5 %ap$ by glaci]s4 ,breccia--a rock compos$ ( angul> fragm5ts1 contra/$ ) pudd+-/one or conglom]ate1 9 :i* ! fragm5ts are r\nd$4 ,buhr/one--a compact1 fl9t-l silici\s rock full ( small cavities1 s nam$ f use z mill/ones4 ,calc-s9t] 7calc>e\s tufa7--a loose cellul> deposit ( calcium c>bonate made by spr+s2 trav]t9e is ! bett] t]m1 z tufa %\ld be left = volcanic ela/ics4 ,cannel coal--a v f9e-gra9$ homog5e\s bitum9\s coal1 giv+ (f mu* gas & burn+ ) a c&le-l flame4 ,*alk--a f9e-gra9$ s(t rock compos$ ess5tially ( calcium c>bonate d]iv$ f m9ute m>9e organisms4 ,*lorite s*i/--a s*i/ose rock 9 :i* *lorite is a pr$om9ant m9]al2 usually gre5i%1 :5ce ! "n4 ,cla/ic rock--=m$ f ! dbris ( brok5-d[n rocks2 ! same z fragm5tal or detrital rock4 ,clay--a t]m commonly appli$ to any s(t1 unctu\s1 adhesive deposit1 b 9 /rict use conf9$ to mat]ial compos$ ( alum9um silicate2 _m s-call$ clays are *iefly silici\s silts or loams4 ,clay iron/one--a clayey rock heavily *>g$ ) iron oxide1 usually limonite2 commonly 9 concretion>y =m4 ,cl9k/one--a "n appli$ to phonolite because ( its metallic cl9k+ s\nd :5 /ruck2 compos$ ( or?oclase1 ) nephelite & "o or m ( ! f]romagnesian m9]als z accessories4 ,*]t--an impure fl9t1 usually ( light color1 occurr+ abundantly 9 concretion>y =m z nodules 9 c]ta9 lime/ones4 ,coal--a c>bonace\s deposit =m$ f ! rema9s ( plants by p>tial decomposition4 ,concretions--aggregates ( r\nd$ outl9es =m$ ab\t a nucleus2 ! mat]ial is v>i\s3 clay1 iron ore1 calcite1 silica1 etc4 ,conglom]ate 7pudd+-/one7--a rock =m$ f r\nd$ pebbles1 consolidat$ gravel4 ,coqu9a--a rock =m$ almo/ :olly ( small & brok5 %ells2 especially appli$ to a %ell lime/one ( ,florida4 ,dacite 7qu>tz-&esite7--an &esite 7q4v47 ) qu>tz4 ,diabase--a dol]ite 7q4v47 :i* has und]gone alt]ation2 consi/s ess5tially ( plagioclase feldsp> & augite1 ) magnetite or titanif]\s iron z a common accessory2 "o ( ! gre5/ones4 ,diatom ooze--a s(t silici\s deposit f\nd on ! bottom ( ! deep sea1 made l>gely or p>tly ( ! %ells ( diatoms2 simil> deposits are =m$ f ! %ells ( radiol>ia4 ,diorite--an igne\s rock usually ( d>k-gre5i% color1 consi/+ ( plagioclase feldsp> & hornbl5de2 (t5 speckl$ f ! comm+l+ ( light feldsp> & d>k hornbl5de4 ,dol]ite--a f9e-gra9$ igne\s rock compos$ ( plagioclase feldsp> 7labradorite or anor?ite7 & augite 7or relat$ f]romagnesian m9]al1 z en/atite1 oliv9e1 or biotite71 ) magnetic or titanif]\s iron z common accessories2 cry/als usually ( m$ium size1 assum+ ! ophitic /ructure2 embraces _m ( ! gre5/ones2 graduates into basalt on ! "o h& & gabbro on ! o!r4 ,dolomite--a magnesian lime/one4 ,drift--9 common ,am]ican usage1 a mixture ( clay1 s&1 gravel1 & b[ld]s =m$ by glacial ag5cies4 ,eolian rocks--deposits =m$ by w9d1 embrac+ especially dunes & "o v>iety ( loess4 ,felsite 7fel/one7--a light-color$ aphanitic rock compos$ ( feldsp> (t5 ) qu>tz1 9 :i* ! cry/allization is v imp]fect or obscure1 giv+ a close-gra9$ texture ) con*oidal fracture & fl9ty aspect2 c]ta9 v>ieties are call$ petrosilex & hllefl9ta4 ,fl9t--a compact d>k *alc$onic or li?oid =m ( qu>tz4 ,free/one--a s&/one ( uni=m gra9 )\t special t5d5cy to split 9 any direction4 ,fulgurites--glassy tubes1 produc$ ?r\gh fusion by lightn+ 9 p5etrat+ s&1 e>?1 or rock4 ,gabbro 7euphotide7--a cry/all9e rock compos$ ( ! plagioclase feldsp>1 labradorite 7or anor?ite71 & diallage 7or a relat$ f]romagnesian m9]al71 ) magnetite or titanif]\s iron z a common accessory4 ,gangue--a t]m appli$ to ! cry/all9e mat]ial 9 :i* ores are imb$d$4 ,ganni/]--ess5tially a qu>tz silt or pulv]iz$ qu>tz us$ = l9+ iron furnaces4 ,g>netite--a rock compos$ l>gely ( g>nets4 ,gee/--residual e>? or clay left by ! decomposition ( rocks1 especially lime/ones4 ,geys]ite--! silici\s s9t] deposit$ ab\t hot spr+s4 ,globulites--m9ute sph]ical bodies embrac$ 9 volcanic glass4 ,gneiss--a foliat$ granite1 consi/+ typically ( qu>tz1 feldsp>1 & mica2 ! feldsp> typically or?oclase4 ,granite--a granul> cry/all9e aggregate ( qu>tz1 feldsp>1 & mica2 ! feldsp> typically or?oclase2 popul>ly & prop]ly us$ = any di/9ctly granul> cry/all9e rock4 ,granitell--a "n us$ to designate a qu>tz-feldsp> rock4 ,granitite--a biotite granite ) qu>tz4 ,granulite--a f9e-gra9$ granite ) little or no mica4 ,gre5s&--a s& or s&/one conta9+ a notable p]c5tage ( gra9s ( glauconite4 ,gre5/one--a compreh5sive t]m us$ to designate igne\s & metamorphic cry/all9e rocks ( gre5i% hue & ( intricate & (t5 m9ute cry/allization2 !y are mo/ly dol]ites1 diabases1 & diorites2 a conv5i5t t]m = field use :]e ! con/itu5ts _c be det]m9$1 & = g5]al use :5 ! v>iety is unimportant4 ,greis5--an aggregate ( qu>tz & mica1 i4e41 a granite )\t feldsp>4 ,greywacke--a s& rock 9 :i* ! gra9s are basic silicates in/ead ( qu>tz4 ,hllefl9ta--a compact fl9t-l felsitic rock4 ,hornbl5dite--a rock ess5tially compos$ ( hornbl5de4 ,horn/one--a v compact1 silici\s rock ( horn-l texture1 alli$ to fl9t2 t]m also appli$ to fl9ty =ms ( felsite4 ,hypog5e rocks--^? =m$ deep )9 ! e>? "u ! influ5ce ( heat & pressure4 ,iron/one--a rock compos$ l>gely ( iron1 usually appli$ to clayey rocks hav+ a l>ge iron cont5t4 ,infusorial e>? 7tripolite7--an e>?y or silt deposit consi/+ *iefly ( ! silici\s %ells ( diatoms4 ,itacolumite--a flexible s&/one ^: pliability is due to an op5 arrangem5t ( s& gra9s :i* are held toge!r by scales ( mica4 ,jasp]--a r$di% v>iety ( *alc$onic qu>tz4 ,k]atophyre--a felsite ) a l>ge p]c5tage ( soda4 ,k]santite--a mica dol]ite consi/+ *iefly ( plagioclase1 augite1 & biotite4 ,lapilli--small fragm5ts ( lava eject$ f volcanoes2 volcanic c9d]s4 ,lat]ite--a r$1 por\s1 f]rug9\s residual e>? ( ,india & o!r tropical c\ntries4 ,lava--a molt5 rock1 especially appli$ to fl[s ^u ! surface1 :e!r f v5ts or f fissures2 also appli$ to ! solidifi$ product4 ,lignite 7br[n coal7--a s(t1 br[n1 impure coal4 ,limburgite--a compact basic igne\s rock ( ! basaltic class1 compos$ ess5tially ( augite & oliv9e1 ) magnetite iron & apatite z common accessories4 ,lime/one--a rock compos$ prim>ily ( calcium c>bonate1 ?\gh magnesium sometimes replaces a "p ( ! calcium4 7,see dolomite & m>ble47 ,lip>ite 7rhyolite7--an acidic igne\s rock ( aphanitic or glassy texture1 *>act]iz$ by fl[age l9es & v>i\s microscopic cry/als2 rhyolite is ! m common ,am]ican "n4 ,loess--a v f9e por\s silici\s silt conta9+ "s calc>e\s mat]ial :i* (t5 collects 9 nodules 7,lss ,k9d*57 or 9 v]tical tubules2 *>act]iz$ by a peculi> compet5cy to /& 9 v]tical walls2 held by "s to be eolian1 by o!rs to be fluvial or lacu/r9e1 & by /ill o!rs to be p>tly eolian & p>tly aque\s4 ,m>ble--typically a granul> cry/all9e lime/one or dolomite produc$ by metamorphic action2 b ! t]m is v>i\sly appli$ to calc>e\s & ev5 to o!r rocks t are color$ ornam5tally & susceptible ( poli%4 ,m>l--an e>? =m$ l>gely ( calcium c>bonate1 usually d]iv$ f ! dis9tegration ( %ells2 or ! calc>e\s accretions ( plants1 notably ! /oneworts2 t]m also sometimes appli$ to glauconitic & o!r f]tiliz+ e>?s4 ,melaphyre--a t]m ( v>y+ usage2 mo/ commonly appli$ p]haps to an alt]$ basalt 7q4v471 especially an oliv9e-be>+ v>iety4 ,meta-diabase--a t]m sometimes us$ = a metamorphic diabase2 9 l mann] meta is prefix$ to dol]ite1 sy5ite1 etc42 n 9 g5]al use4 ,meta-igne\s rock--a metamorphos$ igne\s rock4 ,metamorphic rock--a rock :i* has be5 alt]$1 p>ticul>ly "o :i* has be5 r5d]$ cry/all9e1 or recry/alliz$ by heat & pressure4 ,meta-s$im5t>y rock--a metamorphos$ s$im5t>y rock4 ,microgranite--a v f9e-gra9$ granite4 ,microlites--incipi5t cry/als f\nd 9 glassy lavas2 usually ne$le-%ap$1 or rod-l2 occurr+ s+ly & 9 aggregates4 ,mill/one--see buhr/one4 ,m9ette 7mica-sy5ite7--a rock consi/+ ess5tially ( or?oclase & mica1 or a sy5ite 9 :i* mica replaces hornbl5de or pr$om9ates ov] x4 ,monzonite--a granitic rock compos$ ( or?oclase & plagioclase 9 ne>ly equal proportions1 ) f]romagnesian m9]als2 a rock int]m$iate betwe5 sy5ite & diorite4 ,mud/one--solidifi$ mud or silt1 %ale4 ,nephel9ite--a rock compos$ ess5tially ( nephel9e & augite1 ) magnetite & o!r accessories4 ,nevadite--a v>iety ( rhyolite ( granitoid aspect due to an abundance ( porphyritic cry/als4 ,nodules--concretion>y aggregations ( r\nd$ =m4 ,norite--a f9e-gra9$ rock consi/+ ( plagioclase & hyp]/h5e4 ,novaculite 7hone/one1 oil/one7--a v f9e-gra9$1 h>d s&/one or silt-/one1 us$ = :et/ones4 ,obsidian--a typical =m ( volcanic glass usually ( ! acidic class4 ,onyx--a v>iety ( *alc$onic qu>tz hav+ color$ b&s alt]nat+ ) :ite2 ! 8,mexican onyx0 is a cry/all9e calcium c>bonate1 v>iegat$ ) delicate colors due to iron & manganese4 ,oolite--a lime/one or dolomite compos$ ( small concretions resembl+ ! roe ( fi%4 ,ooze--an exce$+ly s(t wat]y deposit ( ! deep sea2 *>act]iz$ usually by microscopic %ells f :i* x is ma9ly d]iv$1 z diatom ooze1 globig]9a ooze1 etc4 ,or?ophyre 7or?oclase porphyry7--a rock consi/+ ( cry/als ( or?oclase 9 an aphanitic base4 ,pea/one 7pisolite7--a v co>se v>iety ( oolite4 ,peat--! d>k br[n or black residuum aris+ f ! p>tial decomposition ( mosses & vegetable tissue 9 m>%es & wet places4 ,pegmatite--a t]m ( ill-def9$ usage appli$ to rocks ^: gra9 v>ies f co>s] to f9]1 & (t5 takes on peculi> aspects due to ! simultane\s cry/allization & mutual int]gr[?s ( ! cry/als2 graphic granite is a di/9ct type ( pegmatite 9 :i* qu>tz & or?oclase cry/als grew toge!r along p>allel axes s t cross-sections give figures resembl+ c]ta9 ,semitic lett]s 7,fig4 #cde74 ,p]idotite--a v basic igne\s rock compos$ *iefly ( oliv9e ) augite or relat$ f]romagnesian m9]als1 ) magnetite & *romite z accessories4 ,pelites--a g5]al t]m embrac+ clay rocks4 ,p]lite 7pe>l/one7--a =m ( glassy lava made up 9 "p ( small sph]oids =m$ ( conc5tric lay]s :i* h a lu/r\s appe>ance l pe>ls4 ,petrosilex--an old "n = felsite or hllefl9ta4 ,phonolite 7nephelite-tra*yte1 cl9k/one7--a compact resonant igne\s rock =m$ ( sanid9e & nephelite ) accessories4 ,phyllite 7argillite7--a v>iety ( indurat$1 p>tly metamorphos$1 clay silt 9 :i* f9ely dissem9at$ micace\s scales are abundant & lu/r\s2 int]m$iate betwe5 typical clay slate & mica-s*i/4 ,pit*/one--a d>k vitre\s1 acid1 igne\s rock ( less p]fect glassy texture ?an obsidian & m res9\s & pit*-l4 ,plutonic rocks--igne\s rocks =m$ deep )9 ! e>? "u ! influ5ce ( high heat & pressure2 hypog5e rocks2 di/+ui%$ f eruptive rocks =m$ at ! surface4 ,porphyrite--a t]m sometimes us$ = an alt]$ =m ( &esite1 usually porphyritic 9 /ructure4 ,porphyry--a rock consi/+ ( di/9ct cry/als emb$d$ 9 an aphanitic gr\nd-mass4 ,propylite--an alt]$ =m ( &esite & simil> igne\s rocks4 ,protog9e--a hydrat$ micace\s or *loritic v>iety ( granite or gneiss4 ,pumice--a glassy =m ( lava r5d]$ v vesicul> ?r\gh inflation by /eam4 ,pyrocla/ic rocks--fragm5tal or cla/ic rocks produc$ ?r\gh igne\s ag5cies1 embrac+ volcanic a%es1 tuffs1 agglom]ates1 etc4 ,pyrox5ite--an igne\s rock consi/+ ess5tially ( pyrox5e4 ,qu>tzite--a rock consi/+ ess5tially ( qu>tz1 usually =m$ f qu>tzose s&/one by cem5tation or metamorphic action4 ,regoli?--a "n rec5tly sugge/$ by ,m]rill to embrace ! e>?y mantle t cov]s indurat$ rocks1 *iefly residu>y e>?s2 mantle-rock4 ,rhyolite--an aphanitic or glassy igne\s rock %[+ fl[age l9es1 usually appli$ only to ! acidic v>ieties4 ,s&/one--indurat$ s& usually compos$ ( gra9s ( qu>tz1 b n necess>ily s2 sometimes =m$ ( calc>e\s gra9s or ( gra9s ( ! v>i\s silicates4 ,s*i/--a cry/all9e rock hav+ a foliat$ or p>allel /ructure1 splitt+ easily into slabs or flakes1 less uni=m ?an slate2 !y are ma9ly compos$ ( ! silicate m9]als4 ,scori--light1 cellul> fragm5ts ( volcanic rock1 co>s] ?an pumice2 c9d]s4 ,sept>ia--concretions ! int]ior ( :i* h p>t$1 & ! gap+ cracks become fill$ ) calcite or o!r m9]al deposit$ f solution 7,figs4 #cge-gg74 ,s]p5t9e--a rock consi/+ l>gely ( s]p5t9e2 d]iv$ 9 mo/ cases by alt]ation f magnesian silicate rocks4 ,%ale--a m or less lam9at$ rock1 consi/+ ( indurat$ muds1 silts1 or clays4 ,slate--an argillace\s rock :i* is f9ely lam9at$ & fissile1 ei!r due to v uni=m s$im5tation or 7m prop]ly7 to compression at "r angles to ! cleavage planes2 e4g41 common ro(+-slate 7,fig4 #cfb74 ,soap/one 7/eatite7--a s(t unctu\s rock1 compos$ ma9ly ( talc4 ,/alactites--p5dant icicle-l =ms ( calcium c>bonate deposit$ f dripp+ wat]4 ,/alagmite--! complem5t ( /alactites =m$ by calc>e\s wat]s dripp+ ^u ! floors ( cav]ns4 ,/eatite--see soap/one4 ,sy5ite--a granitoid rock compos$ ( or?oclase & hornbl5de1 or o!r f]romagnesian m9]al2 ! "n 0 =m]ly appli$ to a granitoid aggregate ( qu>tz1 feldsp>1 & hornbl5de4 ,ta*ylite 7hyalomelane1 basaltic glass7--a black glass ( basaltic nature correspond+ to ! acidic glasses1 obsidian & pit*/one4 ,till 7b[ld] clay7--a /ony or b[ld]y clay or rock rubbi% =m$ by glaci]s4 ,tra*yte--a "n =m]ly appli$ to a rock possess+ a peculi> r\ghness due to its cellul> /ructure2 b at pres5t ma9ly conf9$ to a compact1 usually porphyritic igne\s rock1 consi/+ ma9ly ( sanid9e associat$ ) v>y+ am\nts ( tricl9ic feldsp>1 augite1 hornbl5de1 & biotite4 ,trap--a g5]al t]m = igne\s rocks ( ! d>k] basaltic types4 ,trav]t9e--a lime/one deposit$ f calc>e\s wat]s1 *iefly spr+s2 usually s(t & cellul>1 & h5ce also call$ calc>e\s tufa1 calc s9t]4 ,tuff 7tufa7--a t]m includ+ c]ta9 por\s granul> or cellul> rocks ( div]se orig9s2 ! volcanic tuffs embrace ! f9] k9ds ( pyrocla/ic detritus1 z a%es1 c9d]s1 etc42 ! calc>e\s tufa embrace ! granul> & cellul> deposits ( spr+s2 ! bett] usage limits ! t]m to volcanic cla/ics4 ,wat]-lime--an impure argillace\s lime/one possess+ hydraulic prop]ties4 ,wacke--a d>k e>?y or granul> deposit =m$ f basic tuffs or f ! disaggregation ( basaltic & simil> rocks2 a t]m :i* may well come into m g5]al use to di/+ui% ! silicate s&s t arise f ! disaggregation1 b only p>tial decomposition1 ( basic rocks1 z arkose does1 ! l products ( ! acidic or granitoid rocks1 & z s&/one does1 ! granul> products ( complete *emical decomposition4 ,,ore-,,deposits4#bjg ,ore-deposits are b a special phase ( ! rock-=m+ processes already discuss$4 ,!y h peculi> int]e/ because ( _! indu/rial value4 ,an ore is simply a rock t conta9s a metal t c be pr(itably extract$1 ?\gh = conv5i5ce ! t]m is us$ m broadly to include unworkable lean ores & ore mat]ial4 ,! metal ne$ n prepond]ate or =m any fix$ p]c5tage ( ! :ole1 = ! crit]ion is solely economic & n petrologic4 ,a gold ore r>ely conta9s m ?an a v small fraction ( "o p]c5t4 ( ! preci\s metal1 :ile high-grade iron ore yields sixty-odd p]c5t4 ( ! metal4 ,9 iron ore1 ! metallic oxide or c>bonate makes up ne>ly ! :ole rock2 9 gold ore1 ! metal is ! m]e/ incid5tal con/itu5t1 f ! petrologic po9t ( view4 ,conc5tration4--,! ess5tial fact 9 ! =mation ( ores is ! unusual conc5tration ( ! metal4 ,!re are va/ quantities ( all ! metals dissem9at$ ?r\gh ! rock sub/ance ( ! e>? & ev5 ?r\gh\t ! hydrosph]e1 b !y d n con/itute ores because !y h no economic value4 ,!y become ores :5 conc5trat$ 9 accessible places to a workable ri*ness4 ,! degree ( conc5tration requir$ is measur$ by ! value ( ! metal4 ,! ess5tial elem5ts = consid]ation are1 !re=e1 7#a7 ! orig9al di/ribution ( ! metallic mat]ials ?r\gh ! rocks1 7#b7 _! solution by circulat+ wat]s 7or1 r>ely1 by o!r means71 7#c7 _! transportation 9 solution to ! place ( deposit1 7#d7 _! precipitation 9 conc5trat$ =m1 & 7#e7 p]haps _! fur!r conc5tration & purification by subsequ5t processes4 ,exceptional & d\btful cases4--,!re are a few cases :]e ore-deposits are made by volcanic fumes or vapors1 b ^! may be neglect$ "h4 ,=m]ly1 ores 7 (t5 attribut$ to vapors suppos$ to arise f ! hot int]ior1 b ?is mode ( orig9 seems incompatible ) physical conditions4 ,ores h be5 attribut$ to wat] orig9ally conta9$ z /eam 9 lavas1 & to wat]s escap+ f ! int]ior ( ! e>?1 ^! wat]s be+ suppos$ to be especially m9]aliz$4 ,direct evid5ce on ?is po9t is obvi\sly beyond rea*4 ,segregation 9 ! molt5 /ate is recogniz$ z a s\rce ( ores1 b its function is probably conf9$ *iefly to p>tial enri*m5t z /at$ bel[4 ,!re are o!r occasional me?ods1 b ! *ief process ( conc5tration1 immeasurably surpass+ all o!rs1 consi/s 9 ! lea*+ out ( ore mat]ials dissem9at$ ?r\gh ! c\ntry rock & _! r$eposition 9 segregat$ =ms1 z an incid5t ( ! recogniz$ sy/em ( wat] circulation4 ,orig9al di/ribution4--,! orig9al di/ribution ( ore mat]ial ?r\gh ! primitive rocks is beyond ! k5 ( pres5t sci5ce1 = ev5 ! nature ( ! true primitive rocks is unkn[n4 ,= pres5t purposes x is suffici5t to reg>d all rocks conc]n$ 9 ore-deposition z ei!r igne\s or s$im5t>y1 & to inquire1 z a fir/ /ep1 h[ f> ord9>y igne\s & s$im5t>y processes contribute to ! segregation ( ore mat]ial1 leav+ = a second /age ( inquiry ! subsequ5t processes ( conc5tration4 ,magmatic segregation4--,9 a few in/ances workable masses ( ore seem to h aris5 f lavas by direct segregation 9 ! molt5 /ate1 )\t ! aid ( subsequ5t conc5tration by wat] action1 on :i* mo/ ores are dep5d5t4 ,x is n improbable t ! segregation ( metallic iron & nickel1 & p]haps o!r metals1 9 ! deep] p>ts ( ! e>? may be a preval5t process1 giv+ rise to masses l ! native iron f\nd 9 basalt 9 ,gre5l&4 ,?is iron closely resembles ! nickel-irons ( meteorites1 :i* may be illu/rations ( simil> action 9 small planet>y bodies t h be5 disrupt$4 ,metallic masses s segregat$ presumably gravitate t[>d ! planet>y c5t] & h5ce1 :atev] _! inh]5t int]e/1 h little relation to a subject ^: basal crit]ion is economic4 ,x is n at all improbable1 h[ev]1 t 9 ! magmatic diff]5tiation ( ! lavas t come to ! surface1 !re is "s metallic segregation t may make ! enri*$ p>ts effective gr\nd = ! conc5trat+ processes ( wat] circulation1 & s det]m9e ! location ( ore-deposits4 ,igne\s rocks are n equally ! seats ( ore-deposits1 ev5 :5 ! circulatory conditions seem to be equally favorable4 ,^! conditions may n really be equally favorable1 b !re is good gr\nd to believe t "s igne\s masses con/itute a ri*] field = conc5tration ?an o!rs4 ,no def9ite rule1 h[ev]1 = di/+ui%+ ri* v>ieties ( rock f lean ones has be5 det]m9$4 ,! basic igne\s rocks are1 on ! :ole1 p]haps some:at ri*] 9 ores ?an ! acidic class1 b !re is no e/abli%$ law4 ,_m acidic rocks be> m & ri*] ores ?an _m basic ones4 ,! view "h ent]ta9$ is t bo? classes are subject to regional enri*m5t ?r\gh conditions connect$ ) _! orig91 z yet little kn[n4 ,m>9e segregation & disp]sion4--,9 ! =mation ( ! s$im5t>y rocks f ! primitive & igne\s rocks !re 0 notable metallic conc5tration 9 "s cases1 & ev5 m notable depletion 9 o!rs4 ,! gr\nd-wat]s ( ! l&1 aft] _! subt]ranean circuits1 c>ri$ into ! wat]-bas9s v>i\s metallic sub/ances 9 solution4 ,^! 7 ei!r precipitat$ e>ly 9 ! m>9e or lacu/r9e drift ( ! wat]s1 or became diffus$ ?r\gh\t ! oceanic body4 ,9 ! ma9 !y appe> to h be5 widely diffus$1 & ei!r to h rema9$ long 9 solution1 or to h be5 v sp>sely deposit$ ?r\gh ! m>9e or lacu/r9e s$im5ts4 ,z a rule1 ^! s$im5ts seem to conta9 less ( valuable ore mat]ial ?an igne\s rocks1 & ?is is rational1 =1 z we %all see1 ! gr\nd-wat] circulation ( ! l& t5ds to conc5trate & hold back a "p ( ! metallic cont5t ( ! l& rocks s t only a residue rea*es ! sea4 ,b !re are important exceptions to ?is g5]al rule ( s$im5t>y leanness4 ,! iron-ore b$s ( ,cl9ton age rang+ f ,new ,york to ,alabama1 & appe>+ also 9 ,wiscons9 & ,nova ,scotia1 =m a /ratum 9 ! mid/ ( ! ord9>y s$im5ts1 & conta9 m>9e fossils4 ,! great ore b$s ( ,lake ,sup]ior 7 orig9ally ( simil> type1 & s are mo/ o!r important iron deposits4 ,x _c be said1 9 mo/ cases1 t ^! iron deposits are m>9e z di/+ui%$ f lacu/r9e or lodgm5t deposits1 b !y are at lea/ s$im5t>y4 ,! f]rug9\s mat]ial 0 orig9ally dissem9at$ widely ?r\gh antec$5t l& rocks1 b 0 conc5trat$ 9 ! c\rse ( ! s$im5t>y processes4 ,lime/one appe>s to h be5 sometimes enri*$ locally 9 lead & z9c1 & m r>ely 9 copp]1 9 ! c\rse ( its s$im5tation4 ,! lead & z9c regions ( ! ,mississippi bas9 h be5 reg>d$ z dep5d5t on su* regional enri*m5t z a prim>y condition4 ,?is localiz$ enri*m5t has be5 attribut$ to solutions br\ght into ! sea f neighbor+ metal-be>+ l&s & precipitat$ by organic action 9 ! sea-wat]1#bjh ?is organic action be+ m effective 9 "s areas ?an 9 o!rs because ( ! unequal di/ribution ( life & ! conc5tration ( its decay+ products4 ,x is assum$ t su* precipitates 7 at fir/ too diffuse to be ( value1 & fur!r conc5tration 0 requir$ to br+ !m toge!r into workable deposits2 b ! fur!r processes appe> to h be5 effective only :]e ! prelim9>y enri*m5t _h tak5 place4 ,at any rate1 ! workable deposits are s+ul>ly localiz$1 :ile ! conc5trative processes are v g5]al4 ,metallic mat]ial is sometimes p>tially conc5trat$ 9 s&/ones & %ales 9 ! process ( s$im5tation1 ?\gh m r>ely4 ,! copp]-be>+ %ale 7,kupf]s*ief]7 ( ! ,ze*/e9 gr\p 9 ,g]many1 s ext5sively work$ along ! flanks ( ! ,h>z ,m\nta9s1 is a /rik+ example4 ,x is 9 e way reasonable to suppose t l&-wat]s1 on rea*+ ! m>g9s ( ! wat]-bas9s1 mu/ occasionally f9d conditions favorable = ! precipitation ( _! metallic cont5ts1 & t ! ratio ( ^! precipitates to o!r mat]ial might be relatively high 9 ! m favorable situations1 & t ?is enri*m5t ( ! c\ntry rock may be a condition prec$5t to a suffici5t subsequ5t conc5tration to yield workable accumulations4 ,x is1 !re=e1 inf]r$ t :ile ! processes ( s$im5tation t5d$ on ! :ole to leanness1 !y gave rise to 7#a7 "s v important ore-deposits1 notably ! *ief iron ores1 ! greate/ ( all ores 9 quantity & 9 real indu/rial value1 & 7#b7 a diffuse enri*m5t ( c]ta9 o!r areas :i* made !m productive "u subsequ5t conc5trative processes1 :ile ! s$im5t>y =mations 9 g5]al 7 left b>r54 ,orig9 ( ore regions4--,f ^! consid]ations x appe>s t = ! fundam5tal explanation ( 8m9+ regions0 we mu/ look ma9ly 7#a7 to magmatic diff]5tiation1 s f> z ! c\ntry rock is igne\s1 & 7#b7 to s$im5t>y enri*m5t1 s f> z ! rock is second>y4 ,! det]m9+ conditions 9 bo? cases are obscure & unpr$ictable1 b ! recognition ( su* regions1 & ( ! function ( prelim9>y diffuse regional enri*m5t1 contributes to a compreh5sive view ( ! complex processes ( ore conc5tration4 ,! subsequ5t processes consi/ 9 ! fur!r conc5tration ( ! ore mat]ial into %eets1 lodes1 ve9s1 & simil> aggregations by gr\nd-wat] circulation1 or else 9 ! purification ( ! ores by ! removal ( useless or delet]i\s mat]ial1 or 9 bo? comb9$4 ,surface residual conc5tration4--,! simple/ ( all modes ( conc5tration takes place 9 ! =mation ( mantle-rock4 ,an insoluble or slightly soluble metallic sub/ance sp>sely di/ribut$ ?r\gh a rock may be conc5trat$ to work+ value by ! decay & removal ( ! ma9 rock mat]ial1 leav+ ! metallic mat]ial 9 ! residu>y mantle4 ,! t9 ores ( ! ,malay p59sula#bji are especially good examples4 ,! cry/als ( t9 oxide 7 orig9ally scatt]$ sp>sely ?r\gh granite & lime/one1 b by _! decay & p>tial removal x has accumulat$ 9 workable quantities4 ,c]ta9 gold fields & c]ta9 iron ores h acquir$ high] values 9 ! same way4 ,su* residu>y mat]ial may be fur!r conc5trat$ by wa% into gul*es or alluvial flats1 9 ! c\rse ( :i* ! light] p>ts ( ! mantle-rock are l>gely c>ri$ away1 & ! heavi]1 includ+ ! metal or its comp\nds1 are ma9ly left beh9d4 ,gold plac]s are ! be/ example4 ,! m9+ ( plac]s by hydraulic processes is b a fur!r ext5sion ( ! natural process ( conc5tration4 ,su* conc5trates 9 pa/ ages h 9 "s cases be5 buri$ by lat] deposits1 & h5ce c]ta9 anci5t s&/ones1 conglom]ates1 & mantle-rocks h become ore-be>+ horizons4 ,! ,r& ( ,s\? ,africa appe>s to be ( ?is type4 ,purification & conc5tration4--,a some:at diff]5t mode ( conc5tration & purification has affect$ c]ta9 ( ! great iron deposits4 ,z already expla9$1 ! iron comp\nds 7 orig9ally dissolv$ f ! iron-be>+ con/itu5ts ( ! primitive or ( igne\s rocks1 or _! d]ivatives1 & 7 deposit$ 9 b$s z *emical /rati=m deposits4 ,9 "s cases !y 7 suffici5tly pure1 z fir/ precipitat$1 to be work$ pr(itably1 b 9 mo/ cases !y 7 s]i\sly affect$ by undesirable m9]al associates4 ,:51 h[ev]1 su* impure deposits are subject$ = long p]iods to ! p]colation ( wat]s f ! surface "u favorable conditions1 ! impurities are (t5 dissolv$ & ! ores conc5trat$4 ,! great ,bessem] ore-deposits ( ,lake ,sup]ior are examples4 ,orig9ally impure c>bonates or silicates1 !y h be5 conv]t$ into ri* & ph5om5ally pure f]ric oxides along c]ta9 l9es ( gr\nd-wat] circulation1 & 9 c]ta9 areas ( free lea*+4 ,van ,hise has %[n ! def9ite relation betwe5 ! wat] circulation & ! production ( ! high-grade ores4#baj ,va/ quantities ( unconc5trat$ lean ores lie 9 ! tracts n ?us purifi$ & enri*$ by circulat+ wat]s4 ,?is does n appe> to be simply residual conc5tration4 ,! wat]s seem to h add$ f]ric oxide br\ght f above1 :ile !y c>ri$ away ! 8impurities10 silica1 c>bon dioxide1 etc4 ,p]haps ?is is an in/ance ( mass action 9 :i* ! ore pres5t aid$ 9 caus+ additions to itself4 ,conc5tration by solution & reprecipitation4--,by a process almo/ ! opposite ( residual conc5tration1 ore mat]ial is (t5 lea*$ out ( ! surface-rock by wat] circulat+ sl[ly ?r\gh its pores1 cleavage planes1 & m9ute crevices1 & is c>ri$ on ) ! circulation until x rea*es "s sub/ance :i* causes a reaction t precipitates ! ore mat]ial4 ,?is sub/ance may be a con/itu5t ( "s rock :i* ! circulat+ wat] enc\nt]s1 su* z organic matt]4 ,m commonly1 ! precipitation seems to be due to ! m+l+ ( wat]s *>g$ ) diff]5t m9]al sub/ances1 ! m+l+ induc+ reaction & ! precipitation ( ! ore4 ,precipitation1 h[ev]1 does n necess>ily foll[ su* comm+l+4 ,! junctions ( und]gr\nd wat]ways are sometimes *>act]iz$ by b>r5ness in/ead ( ri*ness4 ,9 ! expressive phraseology ( ! m9]s1 a tribut>y curr5t sometimes 8makes0 & sometimes 8cuts out40 ,9 *emical phrase1 :5 ! m+l+ wat]s r$uce ! solubility ( ! appropriate sub/ance suffici5tly1 an ore-deposit is =m$2 :5 !y increase its solubility1 !y promote b>r5ness4 ,*anges ( pressure & temp]ature may ent] into ! process1 & mass action may l5d its aid :5 once a deposit is />t$4 ,m concretely /at$1 ! g5]al process ( und]gr\nd ore =mation appe>s to be ?is3 ! p]meat+ wat]s dissolve ! ore mat]ial dissem9at$ ?r\gh ! rock & c>ry x !nce into ! ma9 *annels ( circulation1 usually ! fissures1 brok5 tracts1 por\s belts1 or cav]n\s spaces4 ,if precipitat+ conditions are f\nd !re1 deposition takes place4 ,! precipitat+ conditions may be m]ely *anges ( physical /ate1 su* z cool+ or relief ( pressure1 b probably mu* m g5]ally !y consi/ 9 ! comm+l+ & mutual reaction ( wat]s t h pursu$ diff]5t c\rses & become diff]5tly m9]aliz$1 z impli$ above4 ,9 ^! cases ! metal-be>+ curr5t may be sc>cely m important ?an ! precipitat+ curr5t4 ,s9ce ! solv5t action is a condition prec$5t to deposition1 ! location ( ! greate/ solv5t action fir/ invites att5tion4 ,at pres5t x mu/ be treat$ 9 g5]al t]ms1 = x is n kn[n :at solutions mu/ be =m$ beyond ! fact t !y mu/ include ! ore mat]ial4 ,probably !y mu/ include mu* besides4 ,fur!rmore1 x is n kn[n t deep-seat$ rocks c>ry m ore mat]ial ?an simil> rocks at or ne> ! surface or at any o!r horizon4 ,fanta/ic conceptions ( deep-seat$ metallic ri*ness are to be %unn$ z q beyond practical consid]ation4 ,! wat] circulation is probably v slight bel[ a dep? ( two or ?ree miles at mo/1 & above t dep? !re is little gr\nd to suppose t ! rocks ( "o horizon are inh]5tly m metallif]\s ?an o!rs ( _! k9d4 ,!re is no assignable reason :y ! igne\s rocks at ! surface are n z ri* 9 ore mat]ial z ! igne\s rocks two or ?ree miles bel[1 s9ce all are probably eruptive & ( mu* ! same nature on ! :ole1 be+ 9 _m cases p>ts ( ! same eruptions4 ,location ( greate/ solv5t action4--,solv5t action is probably mo/ int5se :]e ! temp]ature & pressure are highe/1 t is1 9 ! deep] rea*es ( wat] circulation2 b ! am\nt ( wat] pass+ 9 & out ( ! deep] zone is b a small fraction ( t :i* c\rses ?r\gh ! upp] horizons1 & ! total solv5t action is q c]ta9ly mu* great] 9 ! upp] zone ?an 9 ! l[]4 ,at ! same "t ! solutions 9 ! upp] zone are q c]ta9ly m dilute ?an ^? bel[4 ,! horizon ( greate/ solution lies betwe5 ! surface & a level slightly bel[ ! gr\nd-wat] surface1 or1 9 o!r words1 9 ! zone :]e atmosph]e & hydrosph]e cop]ate4 ,surface-wat]s are *>g$ ) atmosph]ic & organic acids & o!r solv5ts1 & _! g5]al effect ^u ! rocks is m>k$ly solv5t d[n to or (t5 bel[ ! p]man5t wat]-level4 ,9 ?is zone conc5tration by residual accumulation may take place1 z already not$1 if ! metallic comp\nds resi/ solution2 o!rwise ?is zone is deplet$ ( its ore mat]ial by solution1 & prep>ation is made = deposition else:]e4 ,solution also cont9ues to take place v>y+ly z ! wat] desc5ds bel[ ?is zone ( dom9ant solution1 & ext5ds probably to ! full dep? ( wat] circulation1 b 9 ! deep] circuit1 precipitation also takes place & ! action becomes complex4 ,) ! wat]s tak+ up & ?r[+ d[n mat]ial at ! same "t1 x is difficult to e/imate ! balance ( results4 ,:5 wat]s t h be5 m9]aliz$ ne> ! surface desc5d1 !y (t5 take on a precipitat+ phase at no great dep? bel[ ! upp] level ( ! gr\nd-wat]2 ?us sulphides t 7 oxidiz$ & dissolv$ ne> ! surface are reprecipitat$1 (t5 at horizons n greatly bel[ ! p]man5t wat]-level4 ,wat]s t dissolve metallic sub/ances 9 ! upp] levels (t5 become *>g$ ) sulphurett$ hydrog5 & o!r precipitants )9 a few scores or a few hundr$s ( feet ( ! surface1 z deep wells abundantly prove4 ,! fre%ness ( surface :i* metallic sulphides (t5 exhibit at ^! levels is fair gr\nd = inf]r+ rec5cy ( deposition & abs5ce ( solv5t action4 ,actual demon/rations ( depositions 9 progress are n want+4 ,%ort-c\rse action4--,! conc5tration :i* ?us takes place by solution 9 ! upp] zone1 foll[$ closely by reprecipitation )9 a few score or a few hundr$ feet1 may well be t]m$ ! %ort-c\rse mode ( ore conc5tration4 ,x f9ds its mo/ important illu/ration 9 :at is commonly kn[n z ! 8second>y enri*m5t0 ( ore-deposits4 ,! ores 9 ! outcropp+ edge ( ! ve9 or lode are dissolv$ by ! surface-wat]s1 c>ri$ a %ort di/ance d[n ! ore tract & r$eposit$1 caus+ enri*m5t at t po9t4 ,?is is only a special case ( :at takes place g5]ally at ?is horizon4 ,x is effective 9 ?is case because x has a previ\s p>tial conc5tration to "w ^u4 ,second>y enri*m5ts ( ?is k9d (t5 conta9 mo/ or all ! workable values ( ! ore tract4 ,if in/ead ( a previ\s conc5tration 9 a ve91 lode1 or simil> ore tract1 !re _h be5 p>tial conc5tration 9 ! c\ntry rock by s$im5tation1 z 9 ! case ( iron-ore b$s & p]haps lead-1 z9c-1 & copp]-impregnat$ s$im5ts1 ! %ort-c\rse me?od may give work+ values n be=e possess$4 ,9 "s ( ! m obscure cases ( previ\s p>tial conc5tration 9 ! cry/all9e & o!r rocks1 x is probably ?is %ort-c\rse action t br+s ! conc5tration up to work+ value4 ,x is probably effective also 9 conc5trat+ ! metallic cont5ts ( c]ta9 igne\s rocks t 7 ri* 9 metallic mat]ial :5 extrud$4 ,h[ f> ?is is true has be51 & /ill rema9s1 a moot$ "q4 ,long-c\rse action4--,aft] ! surface-wat]s h once pass$ ?r\gh a cycle ( dissolv+ & precipitat+ action1 z !y are apt to d )9 ! fir/ few hundr$ feet ( _! c\rses bel[ ! wat]-level1 !y are liable to pass ?r\gh a succession ( dissolv+ & deposit+ /ages1 ea* reaction result+ 9 a /ate t makes a new reaction possible4 ,?is is especially true if ! wat]s pursue deep c\rses4 ,/rictly speak+1 ! precipitations usually conc]n only a "p ( ! sub/ances dissolv$4 ,new sub/ances are (t5 tak5 up 9 ! v act ( ?r[+ d[n ^? already held1 & ! way ?us prep>$ = fur!r *anges4 ,if ! wat] pursues a deep & devi\s c\rse1 x may receive additions by solution & suff] losses by precipitation at _m po9ts 9 its c\rse1 bo? desc5d+ & asc5d+4 ,! *anges are v complex1 & 9 ! case ( a deep or long circuit :]e v>i\s rocks1 pressures1 & temp]atures are enc\nt]$1 ! hi/ory becomes "o long succession ( complexities1 ! full nature ( :i* is n yet reveal$4 ,9 ! deep] circuits1 ea* individual curr5t usually takes on a desc5d+1 a lat]al1 & asc5d+ phase1 ! ?ree be+ necess>y to complete a circuit4 ,! *emical conditions ( ! wat]s 9 ! ?ree phases are probably n %>ply di/+ui%$ f "o ano!r1 & h5ce !re seems to be no def9$ horizon ( conc5tration comp>able to t ne> ! wat]-level already describ$4 ,! *ief di/9ctions 9 ! deep] regions relate to pressure1 temp]ature1 l5g? or dep? ( p5etration1 & duration ( contact4 ,x seems safe to assume1 z a g5]al tru?1 t1 o!r ?+s be+ equal1 ! solutions become m complex & m ne>ly rea* g5]al saturation ! f>!r & ! deep] ! wat]s p5etrate4 ,x has long be5 a moot$ "q :e!r ore-deposits are due *iefly to desc5d+1 to lat]al1 or to asc5d+ curr5ts4 ,! "q 9 its usual =m is too undiscrim9at+ = advantage\s discussion1 b if ! ore-deposits due to surface or %ort-c\rse conc5trations & reconc5trations be set aside1 z 9 "s s5se a sep>ate class1 ! relative functions ( ! desc5d+1 ! lat]al1 & ! asc5d+ portions ( ! deep] circulations become a measurably def9ite "q4 ,two great work+ factors ent] into ! comp>ison3 7#a7 mu* great] circulation 9 ! upp] zone1 :]e lat]al movem5t mo/ prevails2 7#b7 mu* great] heat & pressure 9 ! l[] zone1 :]e ! circulation mu/ be *iefly v]tical4 ,heat & pressure 9 g5]al favor solution1 & h5ce s f> z ?is factor goes1 desc5d+ wat] is likely to be increas+ its m9]al cont5t1 r ?an dim9i%+ x by deposition4 ,b ?is is only g5]al2 p>ticul> elem5ts ( ! solution may be deposit$4 ,9 asc5d+1 z ! same wat] mu/ lat]1 x is pr$ispos$ to deposition f loss ( solv5t p[] ?r\gh r$uction ( pressure & temp]ature4 ,! !oretical balance is "h cle>ly 9 favor ( prepond]ant deposition by ! asc5d+ portion ( ! curr5t4 ,s f> z precipitation is dep5d5t on ! m+l+ ( diff]5tly m9]aliz$ wat]s1 desc5d+ & asc5d+ curr5ts seem to be situat$ mu* alike1 9 g5]al1 = bo? are subject to accessions & mutual unions4 ,! am\nt ( wat] t circulates 9 ! deep] horizons is mu* less ?an t ne>] ! surface4 ,all[+ a few hundr$1 or at mo/ "o or two ?\s& feet = ! special %ort-circuit zone next bel[ ! wat]-level 7x is kn[n to rea* #ajjj to #aejj feet 9 "s cases71 ! wat] circulat+ ?r\gh ! next #ajjj or #bjjj feet is probably sev]al times great] ?an all t circulates at great] dep?s1 & ?is great] circulation above d\btless (fsets1 9 great] or less measure1 ! int5sifi$ action ( ! deep] circulation4 ,mu* ( ! upp] & m rapid circulation is lat]al1 be+ actuat$ by ! slop+ surface ( ! gr\nd-wat]1 :i* 9 turn is det]m9$ by topography1 precipitation1 & o!r surface conditions4 ,!oretical consid]ations1 !re=e1 favor ! view t lat]al fl[ is an important factor 9 ! conc5tration ( ore mat]ial4 ,b z desc5d+ & lat]al curr5ts almo/ inevitably meet & m+le ) asc5d+ curr5ts1 x is difficult to di/+ui%1 9 ! ore-deposits1 ! special functions ( ea* phase ( action4 ,x is ev5 m difficult to det]m9e :e!r ! diff]5t phases are n alike ess5tial to ! mutual reactions on :i* ! deposition dep5ds4 ,x may be z necess>y to h a precipitant z to h a metallic con/itu5t 9 solution to be precipitat$1 & :at is m1 ?is precipitat+ ag5cy may be a sub/ance ( no economic value 9 itself & ( no obvi\s relations to ! sub/ances t =m ! ores4 ,if ! deposition is due solely to a physical /ate1 z relief ( pressure or l[]+ ( temp]ature1 ^! consid]ations d n hold4 ,summ>y4--,! g5]al results are probably ^!3 ,9 ! deep] circuits1 m ore mat]ial is br\ght upw>d & deposit$ ?an is c>ri$ d[nw>d & deposit$1 s t metallic values are %ift$ t[>d accessible horizons4 ,9 ! lat]al curr5ts1 m metallic values are %ift$ t[>d ! trunk-l9es ( circulation--! great crevices & o!r wat]ways--?an are c>ri$ f ^! into ! rock & di/ribut$1 & lat]al segregation results4 ,at ! same "t ! atmosph]ic wat]s act+ at or ne> ! surface conc5trate ore values d[nw>ds4 ,! sum total ( ^! processes is to promote ! developm5t ( ! high] ore values 9 accessible horizons1 & along ! ma9 l9es ( circulation4 ,! influ5ce ( contacts4--,z ore-deposits dep5d on a dissolv+ /ate foll[$ by a deposit+ /ate ( ! wat]s1 & p]haps on a complex succession ( ^! alt]ations1 x is obvi\s t conditions :i* favor *anges ( /ate & ! comm+l+ ( diff]5t k9ds ( wat] are apt to be favorable to ore production4 ,at any rate x is obs]v$ t _m important ore-deposits occur at ! contact betwe5 =mations ( diff]5t "*4 ,! contact ( igne\s rock ) lime/one is a r notable in/ance4 ,x is n to be inf]r$ t su* contacts are g5]ally accompani$ by workable ore-deposits1 b m]ely t a notable proportion ( workable ore-deposits occur at su* junctions4 ,x is rational to suppose t :]e ! *emical nature ( ! two =mations is 9 contra/1 ! wat]s t p]colate ?r\gh ! "o are likely to be m9]aliz$ v diff]5tly f ^? t c\rse ?r\gh ! o!r1 & h5ce t on m+l+ at ! contact1 reactions are specially liable to take place1 & t :5 a valuable metallic sub/ance is pres5t x is liable to be involv$ & by *ance to suff] precipitation4 ,reactions are ! m probable because ! contact is likely to be a plane ( cru/al movem5t1 & h5ce m or less op5 & accompani$ by fractures1 zones ( cru%$ rock & o!r conditions t facilitate circulation & (f] suitable places = ore =mation4 ,! effect ( igne\s intrusions4--,a special case ( mu* importance arises :5 lavas are intrud$ into s$im5ts t h previ\sly be5 p>tially enri*$ 9 ! ways above describ$4 ,! igne\s intrusion n only introduces new contact zones1 & m or less fractur+1 b x br+s into play hot wat]s ) _! int5sifi$ solv5t "w1 _! m active circulation1 & ! reaction betwe5 wat]s ( diff]5t temp]atures4 ,! special effici5cy ( ^! ag5cies is believ$ to be ! det]m9+ factor 9 _m cases4 ,! influ5ce ( rock walls4--,! rock walls !mselves are ?\ght sometimes to be a factor 9 ore-precipitat+ reactions4 ,by mass action1 !y may )draw a con/itu5t ( ! solution & de/roy its equilibrium 9 su* a way z to cause ! precipitation ( ! metallic con/itu5t4 ,once deposit$ on ! walls ores aid1 by mass action1 ! fur!r accretion ( ores4 ,! special =ms :i* ores assume 9 deposition1 z b$s1 ve9s1 lodes1 /ockworks1 dissem9ations1 segregations1 etc41 are *iefly incid5tal to ! local situation 9 :i* ! ess5tial *emical or physical *ange takes place4 ,,*apt] ,,viii4 ,,/ructural 7,,geotectonic7 ,,geology4 ,! /ructural phases :i* rocks assume4--,9 ! previ\s *apt]s1 ! g5]al me?od by :i* rocks are =m$ has be5 set =?1 & _m ( _! /ructural features h be5 t\*$ ^u incid5tally4 ,x rema9s to assemble ! /ructural features already m5tion$1 & to consid] c]ta9 additional /ructural phases :i* rocks assume4 ,,/ructural ,,features ,,( ,,s$im5t>y ,,rocks4 ,9 ! deposition ( s$im5ts 9 ! sea1 or 9 o!r bodies ( /&+ wat]1 ! co>s] portion ( ! mat]ial is usually deposit$ 9 ! %all[ wat] ne> ! %ore :]e ! wave-action is /ronge/1 & ! less co>se ( v>i\s grades is deposit$ at great] & great] di/ances f ! l&1 :ile only extremely f9e silt is usually c>ri$ out to abysmal dep?s 7see p4 #chj74 ,to ?is g5]al law ( di/ribution !re are important exceptions4 ,f9e s$im5ts are sometimes deposit$ ne> ! %ore1 & :]e curr5ts1 tidal agitation1 or float+ ice are effective1 co>se deposits are occasionally c>ri$ f> out f ! %ore4 ,/ratification4--,s$im5t>y rocks are usually arrang$ 9 m or less di/9ct lay]s2 t is1 !y are /ratifi$4 ,! /ratification consi/s prim>ily 9 ! sup]position ( lay]s ( diff]5t con/itution or diff]5t compactness on "o ano!r4 ,lay]s ( l con/itution or compactness are (t5 sep>at$ by films ( diff]5t mat]ial :i* cause ! p>t+s betwe5 !m4 ,! b$d$ arrangem5t ( /ratifi$ rocks is due to v>i\s causes1 b prim>ily to ! v>y+ agitation ( ! wat]s 9 :i* ! s$im5t 0 laid d[n4 ,:]e ! deposit+ wat]s are agitat$ to ! bottom1 co>se s$im5t is likely to be deposit$4 ,:]e ! wat]s are quiet at ! bottom1 f9e s$im5t is ! rule4 ,s9ce ! agitation ( ! wat]s is subject to frequ5t *ange1 x foll[s t co>s] mat]ial succe$s f9]1 & f9] co>s]1 9 ! same place4 ,h5ce arise b$s1 lay]s1 & lam94 ,! t]ms lay] & b$ are g5]ally us$ z synonyms1 :ile lam9 are ?9n] divisions ( ! same sort4 ,! t]m /ratum is sometimes appli$ to "o lay] & sometimes to all ! consecutive lay]s ( ! same sort ( rock4 ,= ! latt] mean+ ! t]m =mation is (t5 us$4 ,sometimes b$d+ seems to h be5 det]m9$ by /rong curr5ts :i* tempor>ily n only prev5t$ deposition ov] a giv5 area1 b ev5 cut away ! loose surface ( deposits already made1 giv+ a firm surface f :i* succe$+ deposits are di/9ct4 ,?is sequ5ce ( ev5ts is sometimes %[n by ! truncation ( lam91 & by o!r signs ( erosion4 ,! common] sorts ( b$d$ rock are lime/ones1 %ales1 s&/ones1 & conglom]ates4 ,! b$d+ ( lime/ones is (t5 caus$ by ! introduction ( ?9 films ( clayey mat]ial :i* int]rupt ! cont9uity ( ! lime accumulation & cause natural p>t+s4 ,sometimes1 h[ev]1 b$d+ arises f v>iations 9 ! physical condition ( ! lime s$im5t itself4 ,lam9ation is n usually conspicu\s 9 pure lime/one1 ?\gh x may be well develop$ 9 ! %aly phases ( ?is rock4 ,%ales are normally lam9at$ z well z b$d$1 & ! lam9ation is (t5 m notable ?an ! ?ick] b$d+4 ,b$d+ 9 %ale may arise f ! introduction ( s&y lam91 or by notable *anges 9 ! texture ( ! %ale mat]ial4 ,simil>ly1 s&/ones are sometimes divid$ into b$s by %aly 7clayey7 p>t+s1 b m (t5 by v>iations 9 ! co>s5ess ( ! s& itself1 or by ! pres5ce ( lam9 t are less coh]5t ?an ^? above & bel[4 ,sometimes ! lay]s appe> to be det]m9$ by ! compact+ ( ! surface ( s& already accumulat$ be=e x 0 buri$ by lat] deposits4 ,s&/ones may be ?ick- or ?9-b$d$1 & _! b$d+ passes ins5sibly into lam9ation4 ,s& deposits usually take place 9 relatively %all[ wat]1 & ! s& is subject$ to mu* %ift+ be=e x f9ds a p]man5t lodgm5t4 ,9 ! c\rse ( ?is %ift+1 b>s are =m$ :i* usually h a r /eep face 9 ! direction 9 :i* !y are be+ %ift$4 ,! s& c>ri$ ov] ! top ( ! b> f9ds lodgm5t on ! slop+ t]race face4 ,! incl9$ lam9 ?us =m$ con/itute a k9d ( b$d+1 b s9ce its planes d n con=m to ! g5]al horizontal attitude ( ! =mation z a :ole1 x is call$ false- or cross-b$d+ or1 m accurately1 cross-lam9ation 7see ,fig4 #cfh74 ,! same /ructure is develop$ on delta fronts & g5]ally 9 wat] %all[ en\gh to be subject to frequ5t agitation at ! bottom4 ,s&/one is cross-b$d$ m commonly ?an o!r sorts ( s$im5t>y rock4 ,! b$d+ ( conglom]ate is due *iefly to v>iations 9 co>s5ess4 ,lam9 or ?ick] lay]s ( s& are frequ5tly f\nd betwe5 lay]s ( co>s] mat]ial4 ,conglom]ate is likely to be ?ick-b$d$1 & cross-b$d+ is common4 ,lat]al gradation4--,:5 ! v>y+ nature ( ! agitation ( ! sea at diff]5t dep?s & along ! diff]5t p>ts ( ! coa/-bord]1 & dur+ diff]5t phases ( ! sea-curr5ts1 is consid]$1 x w be readily und]/ood t s$im5t>y b$s are affect$ by _m irregul>ities1 & t deposits ( "o k9d grade into o!rs horizontally ) great fre$om4 ,?us a b$ ( conglom]ate 7gravel7 may grade lat]ally into s&/one1 & ?is into %ale or lime/one4 ,x is inde$ r m rem>kable t ! s$im5t>y /rata %\ld be z regul> & p]si/5t z !y are1 ?an t !y sometimes grade into "o ano!r4 ,illu/ration3 ,fig4 #cfh4--;,cross-b$d+ 9 s&/one4 ,dells ( ! ,wiscons9 ne> ,kilb\rn1 ,wis4 7,b5nett47 ,special m>k+s4--,! rhy?mical action ( waves gives rise to undulatory lodgm5t1 kn[n z ripple-m>ks 7,fig4 #cbd74 ,!y are usually n ! direct product ( ! surface-waves1 s9ce !y are mu* too small4 ,!y are produc$ ma9ly by ! vibratory movem5t ( ! und]t[1 b !y app>5tly result f v>i\s o!r phases ( vibratory agitation ( ! bottom wat]s4 ,!y are sometimes made by /reams & /ream-l curr5ts4 ,ripple-m>ks are app>5tly pres]v$ indef9itely "u prop] circum/ances4 ,!y are sometimes f\nd1 = example1 on v anci5t qu>tzites4 ,ripples are also made by w9d 7p4 #cg74 ,ripple-m>ks are usually only an in* or two f cre/ to cre/1 b 9 r>e in/ances !y atta9 mu* great] size4 ,examples ( ripple-m>ks #cj feet across are kn[n4#baa ,occasional ridges & depressions ( mu* great] dim5sions are produc$ :i* are attributable to ! =mation ( successive b>s1 or to ! build+ ( wave-cusps4#bab ,rill-m>ks are n infrequ5tly produc$ by ! und]t[ & o!r curr5ts pass+ ov] pebbles1 %ells1 etc4 7,figs4 #cbe & #cbf74 ,illu/ration3 ,fig4 #cfi4--,mud-cracks 9 ,brunswick ,%ale1 ,n4 ,j4 7,kmmel47 ,s$im5ts are sometimes expos$ betwe5 tides1 or "u o!r circum/ances1 = p]iods long en\gh to p]mit dry+ & crack+ at ! surface4 ,on ! return ( ! wat]s1 ! cracks may be fill$ & p]man5tly pres]v$4 ,^! are kn[n z sun-cracks or mud-cracks 7,figs4 #cbh & #cfi74 ,!y *iefly affect %ales1 b are occasionally se5 9 lime/ones & f9e-gra9$ s&/ones4 ,dur+ ! exposure ( ! s$im5ts a %[] may pass & ra9-drop impressions 7,fig4 #cgj7 be made :i* are subsequ5tly fill$ by f9e s$im5t & pres]v$4 ,! size & dep? ( ra9-drop impressions give "s h9t z to ! meteorological conditions ( f>-(f ages4 ,wave-m>ks1 :i* consi/ ( ! fa9t l9e-ridges develop$ on a s&y bea* at ! limit ( ! incom+ wave1 are sometimes pres]v$ & may be se5 occasionally on lay]s ( rock deposit$ millions ( ye>s ago4 ,illu/ration3 ,fig4 #cgj4--,ra9-drop impressions4 7,brigham47 ,concretion>y /ructure4--,v>i\s s$im5t>y =mations conta9 nodules or irregul>ly %ap$ masses ( m9]al matt] unlike ! rock 9 :i* !y occur4 ,:5 ^! nodules consi/ ( matt] aggregat$ ab\t "s c5t]1 !y are call$ concretions4 ,!y are common 9 s$im5t>y rocks1 & "h x may sometimes be se5 t ! aggregation has tak5 place ab\t a %ell1 a leaf1 or "s o!r organic relic4 ,! nuclei are1 h[ev]1 n always organic4 ,! mat]ial ( ! concretion may h come f ! imm$iately surr\nd+ rock1 hav+ be5 fir/ dissolv$ by wat] & !n deposit$ ab\t ! nucleus1 or x may h be5 introduc$ f )\t1 likewise by ! ag5cy ( wat]4 ,9 ! fir/ case1 ! m9]al matt] ( ! concretion is usually "o ( ! m9or con/itu5ts ( ! rock4 ,?us ! commone/ concretions 9 lime/one are compos$ ( impure silica 7*]t1 ,fig4 #cfa72 9 %ale1 ( lime c>bonate or iron sulphide2 9 s&/one1 ( iron oxide4 ,! concretion may be made up almo/ :olly ( conc5trat$ matt]1 9 :i* case ! matt] orig9ally 9 ! place ( ! concretion has be5 cr[d$ aside2 or x may involve mu* ( ! mat]ial ( ! imb$d+ rock4 ,?us ! concretion ( lime c>bonate 9 %ale may be ne>ly pure1 or x may involve mu* ( ! e>?y matt] ( ! %ale1 :ile ! concretion ( iron oxide 9 s&/one commonly includes mu* s&4 ,9 extreme cases1 inde$1 ! conc5trat$ matt] ( ! concretion m]ely cem5ts ! mat]ial involv$ into di/9ct nodules4 ,occasionally ! rock sub/ance itself takes on a concretion>y =m1 all or mo/ ( its mat]ial be+ involv$4 ,illu/ration3 ,fig4 #cga4--;,discoid calc>e\s concretions f po/-glacial clays4 ,ryegate1 ,vt4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cgb4--;,irregul> calc>e\s concretions4 ,ryegate1 ,vt4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cgc4--;,calc>e\s concretions1 "s ( !m %[+ bilat]al symmetry4 ,ryegate1 ,vt4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cgd4--;,irregul> tubul> silici\s concretions 9 ,arik>ee clays4 ,nor?we/ ( ,wildcat ,m\nta91 ,bann] ,co41 ,neb4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,9 size1 concretions may v>y f microscopic dim5sions to huge masses1 #h1 #aj1 or ev5 m feet 9 diamet]4 ,! v>iations 9 %ape are also great4 ,!y may be sph]ical1 elliptical1 discoid1 or !y may assume m irregul> & complex =ms 7,figs4 #cga & #cgb74 ,! conditions ( gr[? h mu* to d ) ! =m4 ,?us a concretion :i* />ts z a sph]e may f9d gr[? easi] 9 "o plane ?an ano!r1 :5 x becomes discoid4 ,two or m concretions sometimes gr[ toge!r1 giv+ rise to complicat$ =ms4 ,"s ( ! mo/ complex & fanta/ic =ms are p]haps to be expla9$ 9 ?is way4 ,concretions sometimes take ! =m ( tubes4 ,"s m9ute tubul> concretions 7 =m$ ab\t rootlets1 b ! l>g] ones appe> to owe _! =m to o!r influ5ces 7,fig4 #cgd74 ,illu/ration3 ,fig4 #cge4--,section ( a concretion 7sept>ium7 ! cracks ( :i* h be5 fill$ by matt] deposit$ f solution4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cgf4--,section ( a concretion1 ! cracks 9 :i* h be5 fill$ by deposition f solution4 ,! fill+ appe>s to h w$g$ ! p>ts ( ! orig9al concretion ap>t4 ,! fill+s are ve9s4 ,"s ( !m %[ t ! ve9-mat]ial 0 deposit$ on bo? walls4 ,ab\t half natural size4 7,photo4 by ,*ur*47 ,"o ( ! mo/ extraord9>y features ( "s concretions ( complex =m is _! symmetry4 ,?is may be ( v>i\s phases2 9 exceptional cases !re is a bilat]al symmetry almo/ z p]fect z 9 ! high] types ( animals4 ,?is is especially true ( c]ta9 calc>e\s concretions develop$ 9 pla/ic clays 7,fig4 #cgc74 ,illu/ration3 ,fig4 #cgg4--,sept>ium f ,cretace\s clays ne> ! ea/ base ( ! ,rocky ,m\nta9s 9 ,montana4 7,photo4 by ,*ur*47 ,concretions sometimes develop cracks )9 !mselves1 & ^! may !n be fill$ ) m9]al matt] diff]+ 9 composition or color f t ( ! orig9al concretions 7,figs4 #cge & #cgf74 ,concretions ! cracks ( :i* h be5 fill$ by deposition f solution1 are call$ sept>ia4 ,!y are especially abundant 9 "s ( ! ,cretace\s %ales & clays4 ,9 n a few cases ! fill+ ( ! cracks appe>s to h w$g$ segm5ts ( ! orig9al concretion f>!r & f>!r ap>t1 until ! out] surface ( ! sept>ium is made up m l>gely ( ve9-matt] ?an ( ! orig9al concretion 7,fig4 #cgg74 ,su* concretions are (t5 popul>ly kn[n z 8petrifi$ turtles40 ,concretions ( ! sort indicat$ above (t5 develop aft] ! enclos+ s$im5t>y rock 0 deposit$4 ,?is is %[n1 among o!r ?+s1 by ! fact t num]\s planes ( lam9ation may sometimes be trac$ ?r\gh ! concretions4 ,concretions also =m 9 wat] dur+ ! deposition ( s$im5t>y rock4 ,exceptionally1 s$im5t>y rock is made up *iefly ( concretions4 ,! *emical precipitates f ! conc5trat$ wat]s ( c]ta9 enclos$ lakes sometimes take ! =m ( m9ute sph]ules :i* resemble ! roe ( fi%4 ,f ?is resemblance ! result+ rock is call$ oolite 7,fig4 #ceg74 ,oolite is n[ =m+ ab\t "s coral reefs1 presumably f ! precipitation ( ! lime c>bonate :i* 0 tempor>ily 9 solution4 ,consid]able b$s ( lime/one are sometimes oolitic4 ,! calcium c>bonate ( su* rock may be subsequ5tly replac$ by silica1 s t ! oolitic /ructure is sometimes f\nd 9 silici\s rock4 ,if ! concretions become l>g]1 say z l>ge z peas1 ! rock is call$ pisolite in/ead ( oolite 7,fig4 #cgh74 ,illu/ration3 ,fig4 #cgh4--,pisolite4 ,half natural size4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #cgi4--;,column> /ructure1 8,devil's ,po/ ,pile40 ,upp] ,san ,joaqu9 ,canyon1 ,si]ra ,nevada ,m\nta9s4 ,b$s ( iron ore are likewise sometimes concretion>y4 ,?us 9 ! ,cl9ton =mation !re are widespread b$s ( 8flaxse$0 ore made up ( concretions ( iron oxide :i*1 individually1 resemble ! se$ :i* has giv5 ! ore its "n4 ,! nucleus 9 ?is case is usually too small = id5tification4 ,secretions4--,:5 cavities 9 rock are fill$ by mat]ial deposit$ f solution1 ! result is sometimes call$ a secretion4 ,secretions !re=e gr[ f )\t t[>d a c5t]1 :ile concretions foll[ ! opposite ord]4 ,cry/al-l9$ cavities 7geodes1 ,fig4 #cei7 & agates 7,fig4 #ceh7 are examples ( secretions4 ,cry/al-l9$ cavities & ve9s are ! same 9 pr9ciple4 ,,/ructural ,,features ,,( ,,igne\s ,,rocks4 ,c]ta9 /ructural features ( igne\s rocks h be5 m5tion$ 9 treat+ ( _! orig9 9 ! previ\s *apt]4 ,:5 a great fl[ ( lava spreads out ^u ! surface1 !re is no int]nal lam9ation or /ratification1 & ! result+ rock is usually classifi$ z massive r ?an /ratifi$2 b :5 a succession ( fl[s occur1 ea* individual fl[ =ms a lay]1 & ! s]ies z a :ole becomes /rati=m4 ,! successive fl[s are n usually coext5sive4 ,if ! lat] fl[s ( ! clos+ /ages ( a p]iod ( vulcanism fail to rea* z f> z ! e>li] ones1 a t]rac$ or /ep-l aspect is giv5 to ! region1 :5ce ! "n trap-rock 7trappe1 /eps7 is d]iv$4 ,su* lava %eets1 especially if ( basalt1 (t5 assume a column> /ructure 9 cool+1 ! columns be+ rude six-sid$ prisms /&+ at "r angles to ! cool+ surfaces 7,figs4 #cgi & #chj74 ,?is ph5om5on is usually be/ develop$ :]e ! %eet is intrud$ betwe5 lay]s ( preexi/+ rock 9 ! =m ( sills4 ,! =mation ( ! columns is sometimes reg>d$ z a v>iety ( concretion>y action1 b m commonly z a result ( contraction4 ,! =m] is sugge/$ by ! ball-&-socket ends ( ! sections ( "s columns 7,fig4 #chb74 ,! developm5t ( ! columns by contraction may be expla9$ z foll[s3 ,! surface ( ! homog5e\s lava contracts ab\t equally 9 all directions on cool+4 ,! contractile =ce may be ?\ght ( z c5t]+ ab\t equidi/ant po9ts4 ,ab\t a giv5 po9t1 ! lea/ numb] ( cracks :i* w relieve ! t5sion 9 all directions is ?ree 7,fig4 #chc74 ,if ^! radiate symmetrically f ! po9t1 ! angle betwe5 any two is #abj1 ! angle ( ! hexagonal prism4 ,simil> radiat+ cracks f o!r c5t]s complete ! columns 7,fig4 #chd74 ,a five-sid$ column w\ld arise f ! failure ( ! cracks to develop ab\t "s "o ( ! po9ts 7,fig4 #che74 ,illu/ration3 ,fig4 #chj4--;,column> /ructure1 obsidian cliff1 ,yell[/one ,p>k4 7,idd+s1 ,u4 ,s4 ,geol4 ,surv47 ,:5 lava is =c$ into crevices or rises to ! surface ?r\gh fissures1 & ! residual portion solidifies 9 !m1 x gives rise to dikes1 z illu/rat$ 9 ,figs4 #b & #dag 7n a true dike74 ,dikes are sometimes affect$ by column> /ructure4 ,9 ?is case1 z 9 all o!rs1 ! columns are likely to be at "r angles to ! cool+ surface4 ,lava solidify+ 9 ! passageway lead+ f ! int]ior ( a volcano gives rise to a neck or plug4 ,if ! lava is =c$ betwe5 b$s ( rock 9 ! =m ( a %eet1 & solidifies !re1 x is call$ a sill4 ,if1 aft] ris+ to a c]ta9 po9t 9 ! /rata1 ! lava ar*es ! b$s above into a dome1 & =ms a great l5s-l or ci/]n-l mass1 x con/itutes a laccoli? 7,fig4 #ccd74 ,if an intrusion ( ! laccoli?ic type faults ! ov]ly+ b$s in/ead ( ar*+ !m1 & especially if ! v]tical dim5sion ( ! intrud$ mass be great 9 comp>ison ) its lat]al dim5sions1 its %ape is m l t ( a plug or core4 ,su* an intrud$ core is a bysmali?#bac 7,fig4 #abd74 ,betwe5 ! bysmali? & ! laccoli? !re are v>i\s gradations1 j z betwe5 ! laccoli? & ! sill4 ,:5 lava =ces aside ! rocks at consid]able dep?s or absorbs !m by solution or by 8/op+10 & !n solidifies 9 great masses ( irregul> or undet]m9$ =ms1 ^! masses are call$ ba?oli?s4 ,illu/ration3 ,fig4 #cha4--,sections ( columns f ,giant's ,causeway1 coa/ ( ,irel&4 ,illu/ration3 ,fig4 #chb4--;,ball-&-socket jo9ts 9 columns ( basalt4 7,scrope47 ,illu/ration3 ,fig4 #chc4--;,diagram to illu/rate ! fir/ /ages 9 ! =mation ( hexagonal columns by contraction4 ,illu/ration3 ,fig4 #chd4--,! completion ( ! hexagonal columns4 ,illu/ration3 ,fig4 #che4--;,diagram to illu/rate ! developm5t ( five-sid$ columns4 ,volcanic cones are famili> /ructures built up ab\t ! v5ts ( active volcanoes1 & w be discuss$ "u vulcanism4 ,,/ructural ,,features ,,aris+ ,,f ,,di/urbance4 ,incl9ation & fold+ ( /rata4--,! orig9al attitude ( b$s1 :e!r =m$ by wat] or by lava-fl[s1 is normally horizontal1 or ne>ly s4 ,bo? k9ds ( deposits1 h[ev]1 occasionally take place on consid]able slopes4 ,modifications ( ! orig9al attitude result f e>? movem5ts1 & ! measurem5t ( ^! modifications is an important feature ( field /udy4 ,x is record$ 9 t]ms ( dip & /rike4 ,! dip is ! incl9ation ( ! b$s ref]r$ to a horizontal plane1 z illu/rat$ 9 ,fig4 #chf1 & is usually measur$ by a cl9omet]1 ! pr9ciple ( :i* is %[n 9 ,fig4 #chg4 ,9 measur+ ! dip1 ! maximum angle is always tak54 ,9 ,fig4 #chf1 = example1 ! angle w\ld be less if ! direction 7 ei!r to ! "r or left ( t indicat$ by ! arr[4 ,! direction z well z ! am\nt ( ! dip is always to be not$4 ,?is mu/ be det]m9$ by ! compass1 to :i* ! cl9omet] may be conv5i5tly atta*$4 ,dip #dj1 ,s4 #bj ,w4 gives ! full record ( ! position ( ! b$ ( rock "u consid]ation4 ,! /rike is ! direction ( ! horizontal edge ( dipp+ b$s1 or m g5]ally1 ! direction ( a horizontal l9e on ! surface ( ! b$s4 ,?is is illu/rat$ 9 ,fig4 #chf4 ,s9ce ! /rike is always at "r angles to ! dip1 ! /rike ne$ n be record$ if ! direction ( ! dip is4 ,?us dip #dj1 ,s4 #bj ,w4 is ! same z dip #dj1 /rike ,n4 #gj ,w4 ,illu/ration3 ,fig4 #chf4--;,diagram illu/rat+ dip & /rike4 7,geikie47 ,illu/ration3 ,fig4 #chg4--,! cl9omet]4 ,illu/ration3 ,fig4 #chh4--,op5 anticl9e1 ne> ,hancock1 ,md4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #chi4--;,clos$ anticl9e1 ne> ,levis ,/ation1 ,quebec4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cij4--;,incl9$ anticl9e4 7,van ,hise1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cia4--,recumb5t anticl9e4 7,van ,hise1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cib4--,syncl9e1 ,c4 ,o4 canal1 #c miles we/ ( ,hancock1 ,md4 ,! b$s are %ale & s&/one ne> base ( ! ,silurian4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,:5 ! b$s incl9e 9 a s+le direction1 !y =m a monocl9e4 ,:5 b$s are ar*$ s z to incl9e away f "o ano!r1 !y =m an up-fold or anticl9e 7,figs4 #chh to #cia74 ,! anticl9e may dep>t f its simple =m1 z %[n 9 ,figs4 #cij & #cia4 ,:5 b$s are curv$ d[nw>d s z to incl9e t[>ds "o ano!r1 !y =m a syncl9e 7,fig4 #cib74 ,:5 b$s assume ! position %[n 9 ,fig4 #cic1 ! folds are said to be isocl9al4 ,:5 !y are ar*$ s z to =m a cone or dome1 & incl9e 9 all directions f a c5tral po9t1 !y are said to h a quaquav]sal dip4 ,:5 consid]able tracts are b5t s z to =m great ar*es or great tr\ghs ) _m m9or undulations on ! flanks ( ! l>g]1 !y are designat$ z geanticl9es1 or anticl9oria 7,figs4 #cid & #cie71 & geosyncl9es or syncl9oria 7,figs4 #cif & #cig74 ,fold+ is (t5 accompani$ by ! developm5t ( slaty cleavage 7p4 #ddj74 ,illu/ration3 ,fig4 #cic4--;,isocl9e4 7,van ,hise1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cid4--;,anticl9orium3 diagrammatic4 7,van ,hise1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cie4--;,anticl9orium4 ,g5]al section 9 ! c5tral massif ( ! ,alps4 7,heim47 ,illu/ration3 ,fig4 #cif4--,syncl9orium3 diagrammatic4 7,van ,hise1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cig4--,syncl9orium1 ,mt4 ,greylock1 ,mass4 7,dale1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #cih4--;,a s]ies ( diagrams illu/rat+ actual field relations 9 regions ( fold$ /rata4 ,we/*e/] ,co41 ,n4 ,y4 7,dana47 ,illu/ration3 ,fig4 #cii4--;,diagram to %[ h[ dip & /rike are record$4 ,illu/ration3 ,fig4 #djj4--,map record ( dip & /rike1 %[+ syncl9al /ructure4 ,illu/ration3 ,fig4 #dja4--,map record ( dip & /rike %[+ anticl9al /ructure4 ,illu/ration3 ,fig4 #djb4--,! /ructure ( ! area %[n 9 ,fig4 #dja1 9 cross-section4 ,illu/ration3 ,fig4 #djc4--,map record ( dip & /rike %[+ plung+ 7dipp+ d[n at ends7 anticl9e4 ,z f\nd 9 ! field1 folds are usually mu* erod$1 & (t5 completely truncat$ 7,fig4 #cih74 ,! det]m9ation ( anticl9al or syncl9al /ructure is !n n bas$ on topography1 or ev5 on su* sections z %[n 9 ,figs4 #cid to #cig1 = su* sections are relatively r>e4 ,! /ructure is det]m9$ by a c>eful record ( dips & /rikes4 ,on ! field map1 ! record may be made z %[n 9 ,figs4 #cii to #dja1 :]e ! free ends ( ! l9es ) b "o free end po9t 9 ! direction ( dip1 :ile ! o!r l9es repres5t ! directions ( /rike4 ,apply+ ?is me?od1 ! /ructure %[n 9 ,fig4 #djj repres5ts a syncl9e1 & t 9 ,fig4 #dja an anticl9e4 ,9 cross-section1 ! /ructure pres5t$ by ,fig4 #dja w\ld appe> z 9 ,fig4 #djb4 ,fig4 #djc %[s a d\bly plung+ anticl9e2 t is1 an anticl9e ! axis ( :i* dips d[n at ei!r end4 ,fig4 #djd %[s a comb9ation ( syncl9es & anticl9es1 & ,fig4 #dje a cross-section along ! l9e ab ( ,fig4 #djd4 ,! outcrops ( rock :]e ! dip & /rike may be det]m9$ may be few & f> betwe51 b :5 !y are suffici5tly ne> "o ano!r1 ! /ructure ( ! rock1 z %[n 9 ,fig4 #dje1 may be work$ out1 ev5 ?\gh ! surface be flat4 ,illu/ration3 ,fig4 #djd4--,map record ( dip & /rike %[+ complex /ructure4 ,illu/ration3 ,fig4 #dje4--;,cross-section ( ,fig4 #djd along ! l9e ab4 ,illu/ration3 ,fig4 #djf4--;,complex fold+4 ,section across ! ,alps f ! neighborhood ( ,zri* t[>d ,como3 ab\t #aaj miles4 7,heim & ,pre/wi*47 ,illu/ration3 ,fig4 #djg4--;,g5]aliz$ fan fold ( ! c5tral massif ( ! ,alps4 7,heim47 ,illu/ration3 ,fig4 #djh4--;,intimate crumpl+ ( b$s ne> head ( ,sp]ry glaci]1 ,mont4 7,mey]s47 ,illu/ration3 ,fig4 #dji4--;,intimate crumpl+ 9 detail1 accompani$ by fault+4 ,jasp] ,hill1 ,i%pem+1 ,mi*4 7,mey]s47 ,mu* ! l>g] portion ( ! e>?'s surface is occupi$ by b$s t reta9 ne>ly _! orig9al horizontal attitude2 b 9 m\nta9\s regions ! b$s h usually suff]$ b5d+1 fold+1 crumpl+1 & cru%+1 9 v>i\s degrees1 9 ! c\rse ( ! de=mations t gave rise to ! m\nta9s4 ,di/ortion is on ! :ole mo/ int5se & *>act]i/ic 9 ! mo/ anci5t rocks kn[n1 ! ,ar*ean1 9 :i* a di/ort$ condition is ne>ly univ]sal1 s f> z obs]vation goes4 ,di/ortion is assign$ *iefly to lat]al ?ru/ aris+ f ! %r9kage ( ! e>?1 z expla9$ 9 ! *apt] on ,e>? ,movem5ts4 ,! simpl]1 & "s r complex =ms ( de=mation1 are %[n 9 ! prec$+ figures1 b ! fold+ is sometimes mu* m complex 7,fig4 #djf71 ! folds sometimes 8fan0 7,fig4 #djg71 & ! b$s ( :i* !y are compos$ are sometimes intricately crumpl$ 7,figs4 #djh to #daj74 ,among ^! v>i\s phases ( de=mation !re are all gradations & comb9ations4 ,ov]turn$ folds rev]se ! ord] ( ! /rata 9 ! "u limb ( ! fold4 ,aft] su* folds h be5 greatly erod$1 s t _! out] =m is lo/ & _! relations h become obscure1 ! rev]s$ b$s are likely to be int]pret$ z ?\gh !y lay 9 natural ord]4 ,9 su* a case z t repres5t$ 9 ,fig4 #daa1 a complex /ructure may be int]pret$ z a simple "o4 ,?us ! /rata ( ,fig4 #daa may h ! /ructure %[n 9 ,fig4 #dab1 #dac1 or #dad1 s f> z dip & /rike %[4 ,illu/ration3 ,fig4 #daj4--,plicat$ lay]s ( ?9-b$d$ *]t 9 lime/one1 et*$ by erosion4 ,l[] ,cambrian 7871 two miles s\?we/ ( ,big ,p9e1 ,inyo ,co41 ,cal4 7,walcott1 ,u4 ,s4 ,geol4 ,surv47 ,jo9ts4--,! surface rocks ( ! e>? are almo/ univ]sally trav]s$ by deep cracks call$ jo9ts 7,figs4 #dae1 #ach & #adj74 ,9 mo/ regions !re are at lea/ two sy/ems ( jo9ts1 ! crevices ( ea* sy/em be+ r\ghly p>allel to "o ano!r1 :ile ^? ( ! two sy/ems1 :]e !re are two1 are approximately at "r angles4 ,9 regions ( great di/urbance1 ! numb] ( sets ( jo9ts is (t5 ?ree1 f\r1 or ev5 m4 ,! jo9ts ( ea* set may be _m y>ds ap>t1 or 9 exceptional cases1 b a few in*es1 or ev5 a fraction ( an in*4 ,g5]ally speak+1 !re are m sy/ems ( jo9ts1 & m frequ5t jo9ts 9 ea* sy/em1 :]e ! rocks are mu* de=m$ ?an :]e !y h be5 b little di/urb$4 ,9 undi/urb$ rocks ! jo9ts approa* v]ticality1 b 9 regions :]e ! rocks h be5 notably de=m$1 ! jo9t planes may h any position4 ,n r>ely !y simulate b$d+ planes1 especially 9 igne\s & metamorphic rocks 7,fig4 #daf74 ,9 ! latt] case especially1 ! cleavage due to jo9t+ is (t5 mi/ak5 = b$d+4 ,!y d n ord9>ily %[ !mselves at ! surface 9 regions :]e !re is mu* mantle rock1 b !y are readily se5 9 ! faces ( cliffs1 9 qu>ries1 &1 9 g5]al1 :]ev] rock is expos$ 7,figs4 #ach & #adj74 ,?\gh "s ( !m ext5d to great] dep?s ?an rock has ev] be5 p5etrat$1 jo9ts are1 aft] all1 sup]ficial ph5om5a4 ,!y mu/ be limit$ to ! zone ( fracture1 & mo/ ( !m are probably mu* m n>r[ly limit$4 ,jo9ts frequ5tly end at ! plane ( contact ( two sorts ( rock4 ,?us a jo9t ext5d+ d[n ?r\gh lime/one may end :]e %ale is rea*$4 ,jo9ts are frequ5tly (fset at ! contact ( lay]s or =mations1 & a s+le jo9t sometimes gives place to _m small] ones4 ,all ^! ph5om5a are to be expla9$ on ! basis ( ! diff]5t con/itution & ela/icity ( v>i\s sorts ( rock4 ,g5]ally speak+1 rigid rock is m readily jo9t$ ?an t :i* is m yield+4 ,jo9ts may rema9 clos$1 or !y may gap4 ,9 ! latt] case1 !y may be wid5$ by solution1 wea!r+1 etc41 b !y are q z likely to be fill$ by detritus f above1 or by mat]ial deposit$ f solution 7ve9s74 ,x is along jo9t-planes t _m ri* ore-ve9s are develop$ 7pp4 #dgh-dhd74 ,illu/ration3 ,fig4 #daa4--,?is diagram might repres5t ei!r isocl9al or monocl9al /ructure4 ,9 ! =m] case ! /rata might h ! /ructure %[n 9 any "o ( ! foll[+ ,figures1 #dab to #dad1 s f> z dip & /rike %[4 7,dana47 ,illu/ration3 ,fig4 #dab4--;,a possible int]pretation ( ,fig4 #daa4 7,dana47 ,illu/ration3 ,fig4 #dac4--;,a possible int]pretation ( ,fig4 #daa4 7,dana47 ,illu/ration3 ,fig4 #dad4--;,a possible int]pretation ( ,fig4 #daa4 7,dana47 ,illu/ration3 ,fig4 #dae4--;,jo9t$ rocks4 ,cayuga ,lake1 ,n4 ,y4 7,hall47 ,jo9ts h be5 ref]r$ to v>i\s causes1 among :i* t5sion1 torsion1#bad e>?quakes1#bae & %e>+#baf are ! mo/ important4 ,mo/ ( !m may probably be ref]r$ to ! t5sion or compression develop$ dur+ cru/al movem5ts4#bag ,9 ! =mation ( a simple fold1 = example1 t5sion-jo9ts p>allel ) ! fold w be develop$1 if t5sion goes beyond ! limit ( ela/icity ( ! rock involv$4 ,if ! axis ( a fold is n horizontal1 t is1 if x 8plunges10 z x commonly does1 a second set ( jo9ts r\ghly p]p5dicul> to ! fir/ w be develop$4 ,if ! uplift be dome-%ap$ & suffici5t to develop jo9ts1 !y w radiate f ! c5t]4 ,x is true t jo9ts affect regions :]e ! rocks h n be5 fold$1 & :]e !y h be5 de=m$ b little1 b de=mation to "s ext5t is well-nigh univ]sal4 ,illu/ration3 ,fig4 #daf4--;,jo9t+ 9 granite4 ,! surface ( ! rock is a jo9t plane4 ,nor?we/ b\nd>y ( ! ,unit$ ,/ates4 ,! edges ( o!r jo9t planes normal to ! surface are also %[n4 7,ransome1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dag4--,s&/one dike4 ,nor!rn ,cali=nia4 7,dill]1 ,u4 ,s4 ,geol4 ,surv47 ,a m9or cause ( t5sion-jo9t+ is %r9kage1 due 7#a7 to cool+1 z 9 ! developm5t ( ! column> /ructure ( c]ta9 lavas1 & 7#b7 to dessication1 z %[n by ! cracks develop$ 9 mud :5 x dries4 ,^! causes1 h[ev]1 are n believ$ to affect rock /ructures to any consid]able dep?4 ,torsional jo9ts & jo9ts due to e>?quake vibrations appe> to be special phases ( t5sion-jo9ts4 ,two or m sets ( jo9ts may also be produc$ by compression1 ! numb] be+ dep5d5t on ! complexity ( ! fold+4 ,_m compression-jo9ts correspond 9 direction ) planes ( %e>+4 ,!y are (t5 associat$ ) m9or fault+ & ) slaty cleavage4 ,t5sion-jo9ts appe> to be mu* m widely di/ribut$ ?an compression-jo9ts4 ,s&/one dikes4--,exceptionally1 op5 jo9ts are fill$ by ! intrusion ( s$im5t>y mat]ial f b5ea?4 ,?us h aris5 ! rem>kable s&/one dikes#bah ( ! ,we/1 especially ( ,cali=nia 7,fig4 #dag74 ,su* dikes are sometimes sev]al miles 7n9e at lea/7 9 l5g?4 ,! s& ( ^! dikes 0 =c$ up f b5ea? ei!r by e>?quake movem5ts or by hydro/atic pressure4 ,illu/ration3 ,fig4 #dah4--;,diagram ( a normal fault4 ,faults4--,! b$s on "o side ( a jo9t-plane or fissure are sometimes elevat$ or depress$ relative to ^? on ! opposite side1 & ! displacem5t is kn[n z a fault 7,figs4 #dah & #dai74 ,! jo9t-planes may h any position1 & h5ce fault-planes may v>y f v]ticality to approximate horizontality4 ,! angle by :i* ! fault-plane dep>ts f a v]tical position is kn[n z ! hade 7bac1 ,fig4 #dah74 ,! v]tical displacem5t 7ac7 is ! ?r[ & ! horizontal displacem5t 7bc7 ! heave4 ,! heave & ! ?r[ are to be di/+ui%$ f ! displacem5t1 :i* is ! am\nt ( movem5t along ! fault-plane 7ab1 ,fig4 #dah74 ,! cliff above ! edge ( ! d[n?r[ side is a fault-sc>p4 ,9 _m1 probably 9 mo/ cases1 ! sc>p has be5 de/roy$1 or at any rate greatly obscur$ by erosion2 b occasionally fault-sc>ps ( m\nta9\s heights1 z along ! ea/ face ( ! ,si]ras & along _m ( ! bas9 ranges ( ,utah1 ,nevada1 etc41 are f\nd ?\gh mu* modifi$ by erosion 7,fig4 #dai74 ,faults sometimes arise f ov]-int5se fold+ 7,fig4 #dbj74 ,a de=mation :i* at "o po9t results m]ely 9 a b5d+ ( ! b$s1 may occasion a fault at ano!r4 ,faults may pass into folds ei!r v]tically 7,figs1 #dba & #dbb7 or horizontally 7,fig4 #dbc74 ,9 su* cases1 ?ick5+ & ?9n+1 & /ret*+ & %ort5+ ( ! b$s is (t5 involv$ 7see ,figs4 #dba & #dbb74 ,faults are (t5 due to ! great] settl+ ( ! b$s on "o side ( a fissure ?an on ! o!r1 )\t special disposition to fold4 ,illu/ration3 ,fig4 #dai4--;,a fault-sc>p2 ! triangul> faces ris+ abruptly above ! pla9 at ! ends ( ! spurs4 7,davis47 ,illu/ration3 ,fig4 #dbj4--;,diagrams %[+ relations ( faults & folds4 ,illu/ration3 ,fig4 #dba4--,! fault above grades into a fold bel[4 ,?ick5+ & ?9n+ ( lay]s next ! fault-plane evid5t4 ,bas$ on exp]im5tal results ( ,willis 7#ac? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dbb4--;,fault bel[ grad+ into fold above4 ,/ret*+ & ?9n+1 & %ort5+ & ?ick5+ ( b$s "u pressure is involv$4 ,bas$ on exp]im5tal results ( ,willis4 ,illu/ration3 ,fig4 #dbc4--;,diagram %[+ a fault grad+ into a monocl9e horizontally4 ,illu/ration3 ,fig4 #dbd4--,slick5side surface4 7,pre/wi*47 ,! rock on ei!r side ( a fault-plane is (t5 smoo!d z ! result ( ! friction ( movem5t4 ,su* surfaces are slick5sides 7,fig4 #dbd74 ,a slick5side surface has "s resemblance to a glaciat$ surface1 b g5]ally gives evid5ce ( great] rigidity betwe5 ! mov+ surfaces4 ,faults are ( two g5]al classes1 normal & rev]s$4 ,9 ! normal fault 7,fig4 #dah7 ! ov]hang+ side is ! d[n?r[ side1 i4e41 ! d[n?r[ is on ! side t[>ds :i* ! fault-plane incl9es1 z ?\gh ! ov]hang+ b$s _h slidd5 d[n ! slope4 ,normal faults1 z a rule1 indicate an ext5sion ( /rata1 ?is be+ necess>y to p]mit ! dissev]$ blocks to settle d[nw>ds4 ,9 ! rev]s$ fault1 ! ov]hang+ b$s appe> to h mov$ up ! slope ( ! fault-plane1 z ?\gh ! displacem5t took place "u lat]al pressure4 ,?is is cle>ly %[n to be ! case :]e an ov]fold passes into a rev]s$ fault 7,fig4 #dbj74 ,rev]s$ faults are fur!r illu/rat$ by ,figs4 #dbe1 #dbf1 & #dbg4 ,:]e ! plane ( ! rev]s$ fault approa*es horizontality1 ! fault is (t5 call$ a ?ru/-fault1 or an ov]?ru/4 ,9 su* cases ! ?r[ is to be di/+ui%$ f ! /ratigraphic ?r[ 7see ,fig4 #dbf74 ,9 ?ru/-faults1 ! heave is (t5 great4 ,! ea/]n face ( ! ,rocky ,m\nta9s ne> ! b\nd>y-l9e betwe5 ! ,unit$ ,/ates & ,canada has be5 pu%$ ov] ! /rata ( ! bord]+ pla9s to a di/ance ( at lea/ eight miles4#bai ,ov]?ru/s ( l gigantic displacem5t h be5 detect$ 9 ,briti% ,columbia1#bbj ,scotl&1#bba & else:]e4 ,illu/ration3 ,fig4 #dbe4--,p]spective view & v]tical section ( a ?ru/-fault4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dbf4--;,diagram ( a ?ru/-fault illu/rat+ ! sev]al t]ms us$ 9 describ+ faults4 ,! di/9ctions betwe5 heave & displacem5t1 & betwe5 ?r[ & /ratigraphic ?r[1 are to be especially not$4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dbg4 --,/ep-fold %[+ 79 #a7 break 9 ! massive lime/one b$ :i* det]m9es ! plane ( ! break-?ru/ along :i* ! displacem5t %[n 9 #b takes place4 7,willis1 ,u4 ,s4 ,geol4 ,surv47 ,sometimes a fault bran*es 7,fig4 #dbh7 & sometimes ! fault+ is di/ribut$ among a s]ies ( p>allel planes at %ort di/ances f "o ano!r1#bbb in/ead ( be+ conc5trat$ along a s+le plane1 ?us giv+ rise to a di/ributive fault 7,fig4 #dbi74 ,?is is p]haps m common 9 normal ?an 9 rev]s$ fault+4 ,illu/ration3 ,fig4 #dbh4--;,bran*+-fault4 7,p[ell47 ,illu/ration3 ,fig4 #dbi4--;,diagram %[+ a s]ies ( small faults--di/ributive fault+4 ,illu/ration3 ,fig4 #dcj4--;,fault 9 ,g]+ s]ies4 ,ne> ,rutl& ,sid+1 ne> ,craw=d1 ,neb4 7,d>ton1 ,u4 ,s4 ,geol4 ,surv47 ,! am\nt ( ?r[ occasionally rea*es sev]al ?\s& feet4 ,occasionally faults ( incr$ible dim5sions are report$1 b ^! are p]haps mis9t]pretations4 ,faults are obs]v$ to die out gradually :5 trac$ horizontally1 sometimes by pass+ into monocl9al folds1 & sometimes )\t connection ) fold+4 ,9 dep? !y probably die out 9 simil> ways 9 mo/ cases4 ,:]e ! ?r[ is great1 !y probably give place to folds bel[ 7,fig4 #dba74 ,o!r ph5om5a ( fault+ are illu/rat$ by ,figs4 #dcj-dce4 ,a fault ( ?\s&s1 or ev5 hundr$s ( feet is probably ! sum ( num]\s small] slipp+s di/ribut$ ?r\gh long int]vals ( "t4 ,fault+ is probably "o ( ! common causes ( e>?quakes4 ,illu/ration3 ,fig4 #dca4--;,contort$ & fault$ lam9at$ rock4 ,cook ,inlet4 7,gilb]t1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dcb4--;,fault+ %[n 9 a cobble/one4 ,! fault-planes h become ve9s by deposition f solution4 ,! figure %[s h[ ! relative ages ( cross+-faults may be det]m9$4 7,s*rad]1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dcc4--;,figure %[+ m9ute fault+4 ,! l5g? ( ! specim5 is #h in*es4 ,! numb] ( faults is ne>ly #ajj4 7,photo4 by ,*ur*47 ,illu/ration3 ,fig4 #dcd4--;,diagram illu/rat+ common ph5om5a ( a fault$ region4 7,dana47 ,illu/ration3 ,fig4 #dce4--;,diagram %[+ a fault1 ! plane ( :i* =ms an op5 fissure & has be5 fill$ ) dbris f above4 7,p[ell47 ,! significance ( faults4#bbc--;,faults af=d a valuable indication ( ! conditions ( /ress to :i* a region has be5 subject$1 b "s caution mu/ be ex]cis$ 9 _! int]pretation4 ,normal faults usually indicate an ext5sion ( ! surface suffici5t to p]mit ! fault-blocks to settle d[n unequally4 ,rev]s$ faults usually signify a compression ( ! surface :i* requires ! blocks to ov]lap "o ano!r m ?an !y did be=e ! fault+4 ,9 o!r words1 normal fault+ usually implies t5sional /ress1 & rev]s$ fault+ compressional /ress4 ,x is n difficult to see1 h[ev]1 t 9 an int5sely compress$ & fold$ region !re might be cases ( normal fault+ on ! cre/s ( folds :]e local /ret*+ took place1 & t rev]s$ faults might occur ev5 9 regions ( t5sion4 ,b su* cases mu/ usually be local1 & capable ( detection & elim9ation by a /udy ( ! ph5om5a ( ! surr\nd+ region4 ,^! exceptional cases aside1 ! g5]al inf]5ce f prevail+ normal faults is t ! regions :]e !y occur h und]gone /ret*+1 :ile ! inf]5ce f ! less widely di/ribut$ rev]s$ faults is t ! surface :]e !y occur has und]gone compression4 ,9 view ( ! curr5t op9ion t ! cru/ ( ! e>? has be5 subject$ to great lat]al ?ru/ z a result ( cool+1 x is well to make especial note ( ! fact t ! faults :i* imply /ret*+ are call$ normal because !y are ! m abundant2 & t ! faults :i* imply ?ru/ are less common1 & are /yl$ rev]s$4 ,! num]ical ratio ( normal to rev]s$ faults has nev] be5 closely det]m9$1 b normal faults v greatly prepond]ate1 & are e/imat$ by "s writ]s to embrace #ij-odd p] c5t4 ( ! :ole4 ,! te/imony ( normal faults is support$ by ! preval5ce ( gap+ crevices1 & ( ve9s :i* are b crevices t /ood op5 until !y 7 fill$ by deposition4 ,all ^! ph5om5a seem to te/ify to a /ret*$ condition ( ! l>g] "p ( ! surface ( ! cont95ts4 ,?is w aga9 claim att5tion 9 ! /udy ( ,e>? ,movem5ts4 ,illu/ration3 ,fig4 #dcf4--;,diagram %[+ an area ( rock ) monocl9al /ructure4 ,"o lay] notably unlike ! o!rs4 ,effect ( fault+ on outcrops4--,fault+ may br+ ab\t num]\s complications 9 ! outcrop ( rock =mations4 ,9 a s]ies ( =mations hav+ a monocl9al /ructure 7,fig4 #dcf71 _m *anges may be introduc$4 ,let x be suppos$ 9 ! foll[+ cases t1 aft] fault+1 ! surface has be5 r$uc$ to plan5ess by erosion4 ,if ! fault-plane be p>allel to ! /rike ( ! b$s 7ab1 ,fig4 #dcf71 & h5ce a /rike fault1 ! outcrop ( a giv5 lay] may be duplicat$ 7,h1 ,fig4 #dcg71 or x may be elim9at$ altoge!r 7,fig4 #dch74 ,if ! fault-plane be p>allel to ! direction ( dip 7cd1 ,fig4 #dcf71 a dip fault1 ! lay] ,h w outcrop1 z 9 ,fig4 #dci1 if ! d[n?r[ 0 on ! f> side1 or z 9 ,fig4 #ddj if ! d[n?r[ 0 on ! opposite side4 ,9 bo? cases ! outcrop ,h is (fset1 ! am\nt ( ! (fset decreas+ ) increas+ angle ( dip & increas+ ) increas+ ?r[ ( ! fault4 ,if ! fault be oblique to ! direction ( dip & /rike 7ef1 ,fig4 #dcf71 an oblique fault1 ! outcrop ( su* a lay] z ,h w h ! relations %[n 9 ,fig4 #dda if ! d[n?r[ 0 to ! left1 & t %[n 9 ,fig4 #ddb if ! d[n?r[ 0 to ! "r4 ,9 ! =m] case1 x is said t !re is (fset ) ov]lap2 9 ! latt]1 (fset ) gap4 ,! am\nt ( ! ov]lap & gap1 respectively1 increases ) ! increase ( ?r[ & hade1 & decreases ) increase ( dip4 ,9 all cases ! outcrop 7aft] ! degradation ( ! up?r[ side7 is %ift$ d[n dip4 ,illu/ration3 ,fig4 #dcg4--,same z ,fig4 #dcf1 aft] 7#a7 displacem5t by a /rike fault & 7#b7 base-level+4 ,! outcrops ( c]ta9 b$s are repeat$4 ,illu/ration3 ,fig4 #dch4--;,diagram illu/rat+ h[ a /rike fault 9 su* a /ructure z t %[n 9 ,fig4 #dcf may cause ! outcrop ( c]ta9 b$s to disappe>4 ,illu/ration3 ,fig4 #dci4--;,diagram illu/rat+ h[ a dip fault 9 ! /ructure %[n 9 ,fig4 #dcf affects ! outcrop :5 ! d[n?r[ 0 on ! f>!r side ( ! fault-plane4 ,illu/ration3 ,fig4 #ddj4--,same z ,fig4 #dci1 except t ! d[n?r[ 0 on ! opposite side4 ,illu/ration3 ,fig4 #dda4--,oblique fault 9 ! /ructure %[n 9 ,fig4 #dcf4 ,! d[n?r[ 0 on ! left side4 ,! outcrop ( lay] ,h is (fset ) ov]lap4 ,illu/ration3 ,fig4 #ddb4--,same z ,fig4 #dda1 except t ! d[n?r[ 0 on ! "r side1 & ! (fset is ) a gap in/ead ( an ov]lap4 ,illu/ration3 ,fig4 #ddc4--;,diagram %[+ effect ( fault+ on ! outcrops ( syncl9al b$s4 ,illu/ration3 ,fig4 #ddd4--;,diagram %[+ effect ( fault+ on outcrops ( anticl9al b$s4 ,illu/ration3 ,fig4 #dde4--;,diagram illu/rat+ ! effect ( dim9i%+ ?r[ on outcrops 9 regions ( fold$ rocks4 ,if a fault crosses folds at "r angles to _! axes1 ! effect is to *ange ! di/ance betwe5 ! outcrops ( a giv5 b$ on opposite sides ( ! fault1 aft] ! truncation ( ! fold$ b$s4 ,! di/ance is decreas$ on ! up?r[ side ( a syncl9e 7,fig4 #ddc7 & increas$ on ! up?r[ side ( an anticl9e 7,fig4 #ddd74 ,if ! ?r[ ( a fault 9 tilt$ b$s dim9i%es 9 "o direction1 x may cause b$s to outcrop1 z %[n 9 ,fig4 #dde4 ,v>i\s o!r complications arise "u o!r circum/ances4 ,s9ce faults r>ely %[ !mselves 9 ! topography ( ! surface1 except "u special circum/ances 7see p4 #aea71 _! detection & measurem5t is usually bas$ on ! /udy ( ! relations ( ! b$s involv$1 z illu/rat$ by ,figs4 #dcf-dde4 ,,*apt] ,,ix4 ,,! ,,movem5ts ,,& ,,de=mations ,,( ,,! ,,e>?',s ,,body 7,,dia/rophism74 ,! body ( ! e>? is subject to an inf9ite v>iety ( movem5ts1 rang+ f ! almo/ inconceivably rapid to ! almo/ imp]ceptibly sl[1 & f ! almo/ immeasurably m9ute to ! enorm\sly massive2 b1 = practical treatm5t1 !y fall ma9ly into two c\plets3 7#a7 ! m9ute & rapid1 & 7#b7 ! sl[ & massive4 ,sudd5 movem5ts ( local masses1 giv+ rise to int5se vibrations1 are put 9 ! fir/ class4 ,!re are innum]able m9ute & sl[ movem5ts1 b unless !y rise to appreciable magnitude by long cont9uance1 !y are neglect$4 ,,m9ute ,,& ,,rapid ,,movem5ts4 ,! cru/ ( ! e>? is 9 a /ate ( p]petual tremor4 ,= ! mo/ "p1 ^! tremors are too m9ute to be s5sible1 b are reveal$ by delicate in/rum5tal devices4 ,"s ( !m are b ! decl9+ /ages ( s5sible vibrations1 b o!rs are m9ute f _! inception4 ,_m ( !m spr+ f ! ord9>y incid5ts ( ! surface1 & claim att5tion *iefly z ob/acles to ! /udy ( m significant oscillations4 ,w9ds1 waves1 wat]falls1 ! tread ( animals1 ! rumble ( traffic1 ! bla/s ( m9es1 ! *anges ( temp]ature1 ! v>iations 9 atmosph]ic pressure1 ! weight+ ( ra9fall & ! light5+ ( evaporation1 ! rupture ( rock or ice or froz5 e>?1 & _m o!r processes1 make _! contributions to local & m9ute movem5ts4 ,= ! great] "p1 ^! vibrations are sup]ficial 9 orig91 & are soon damp$ beyond recognition by disp]sal & by ! inela/ic & discont9u\s nature ( ! loos] mat]ial ( ! surface4 ,:5 a tempor>y rigid cru/ is =m$ by freez+1 z 9 w9t]1 ^! surface vibrations are transmitt$ ) mu* less loss1 & ! di/ances at :i* ! rumble ( w9t] traffic is he>d1 is a good illu/ration ( ! function ( cont9uity & solidity 9 ! conveyance ( vibrations4 ,e>?quakes4 ,:5 ! tremors spr+ f s\rces )9 ! e>? itself & are ( appreciable viol5ce1 !y are recogniz$ z e>?quakes4 ,! s\rces ( e>?quake tremors are v>i\s4 ,! mo/ preval5t is probably ! fracture ( rocks & ! slipp+ ( /rata on ea* o!r 9 ! process ( fault+4 ,! int]pretation ( movem5ts ( ?is class has n[ be5 s f> p]fect$ t ! l5g? & dep? ( ! fault1 ! am\nt ( ! slip1 & ! direction ( ! hade are capable ( approximate e/imation4#bbd ,to ! same class belong ! movem5ts due to slump+4 ,!y are illu/rat$ by ! slid+ & arre/ ( great masses ( s$im5t along ! /eep fronts ( deltas1 & ( ! accumulations ( deep-sea oozes on /eep subm>9e slopes4 ,su* slump+ is1 9 reality1 sup]ficial fault+4 ,seismic tremors (t5 att5d volcanic eruptions1 & are !n probably attributable to ! sudd5 fracture & displacem5t ( rock by ! p5etration ( lava1 or by rapid & unequal heat+4 ,!y are p]haps also due sometimes to ! sudd5 g5]ation or cool+ ( /eam 9 und]gr\nd conduits1 crevices1 & cav]ns1 ! action possibly be+ 9 "s cases ( ! 8wat]-hamm]0 type4 ,9 r>e in/ances1 probably1 ! bur/+ ( b$s ov]ly+ p5t-up non-volcanic gases may give orig9 to e>?quakes4 ,a m sup]ficial s\rce ( e>?quake vibrations is ! collapse ( ! ro(s ( subt]ranean cav]ns4 ,seismic vibrations seem to be 9 "p compressional1 9 "p di/ortional1 9 "p 7on ! surface7 undulatory1 & 9 "p irregul>4 ,! di/ortional are especially significant1 z !y seem to imply a solid m$ium ( transmission4 ,po9ts ( orig91 foci4--,x is probable t ne>ly or q all e>?quake movem5ts />t )9 ! upp] t5 miles ( ! cru/1 & mo/ ( !m )9 ! upp] five4 ,"s ( ! e>li] e/imates inde$ plac$ ! po9ts ( orig9 z deep z #bj or #cj miles1 b 9 ^! cases ! necess>y corrections1 discuss$ bel[1 7 neglect$4 ,mo/ ( ! rec5t & m accurate e/imates fall )9 ! limits giv54 ,! me?od ( e/imat+ ! dep? ( ! c5t]s ( di/urbance consi/s 9 obs]v+ ! directions ( ?r[ or ?ru/ ( bodies at ! surface1 & 9 reg>d+ ^! z repres5t+ ! l9es ( em]g5ce ( ! e>?quake-waves4 ,by plott+ ^! l9es ( em]g5ce1 & project+ !m backw>ds to _! und]gr\nd cross+s1 a fir/ approximation to ! location ( ! focus is rea*$ 7! l9es ,,ef1 ,fig4 #ddf74 ,f ! nature ( ! case1 ! obs]vations ( ! angles ( em]g5ce _c be v accurate1 b an ef=t is made to limit ! error by mak+ ! numb] ( obs]vations great4 ,two sy/ematic corrections are to be appli$ to all su* e/imates1 ! "o = v>y+ ela/icity & d5sity1 & ! o!r = v>y+ cont9uity4 ,bo? r$uce ! e/imat$ dep?4 ,9 mak+ ! correction = v>y+ ela/icity1 x mu/ be not$ t ! velocity ( vibrations v>ies directly z ! squ>e root ( ! ela/icity1 & inv]sely z ! squ>e root ( ! d5sity4 ,! velocity is also accel]at$ by increase ( temp]ature4 ,! ela/icity1 temp]ature1 & d5sity all increase ) dep?4 ,!oretically1 ! increase ( velocity due to ! increas+ ela/icity & temp]ature ( increas+ dep?s1 ov]balances ! ret>dation due to increas+ d5sity1 & rec5t obs]vations on ! transmission ( seismic waves ?r\gh deep *ords ( ! e>? h confirm$ ?is conclusion4 ,! pa? ( ! vibration w1 !re=e1 be curv$ t[>d ! surface1 z po9t$ out by ,s*midt & illu/rat$ 9 ,fig4 #ddf1 tak5 f 8 discussion4#bbe ,f ?is x is cle> t ! focus is n s deep z impli$ by ! simple backw>d projection ( ! l9es ( em]g5ce4 ,illu/ration3 ,fig4 #ddf4--;,diagram illu/rat+ by clos$ curves ! diff]5t rates ( propagation ( seismic tremors f a focus ,f1 &1 by l9es normal to ^!1 ! *ang+ directions ( propagation ( ! wave-front4 ,x w be se5 t ! pa?s ( propagation curve upw>ds 9 approa*+ ! surface4 ,if ! l9es ( em]g5ce1 z at ,e & ,e1 be project$ backw>ds1 z to ,f1 ! po9ts ( cross+ w be bel[ ! true focus4 ,a second correction mu/ be made = ! diff]5ces ( cont9uity ( ! upp] rock 9 ! v]tical & horizontal directions4 ,9 ! out] "p ( ! e>?1 ! cont9uity 9 horizontal directions is int]rupt$ by v]tical fissures4 ,7 ^! n usually fill$ ) wat]1 !y w\ld soon kill ! horizontal compon5t ( ! seismic wave1 & ! residual portion w\ld be direct$ almo/ v]tically to ! surface1 = ! wid? ( ! fissures is almo/ always great] ?an ! amplitude ( ! seismic vibrations4 ,! wat] re/ores ! cont9uity1 9 a measure1 b n p]fectly1 = ! ela/icity ( wat] is mu* less ?an t ( rock4 ,x is cle> t 9 horizontal movem5t !re mu/ be a con/ant transf] f rock to wat] & f wat] to rock1 & ?is mu/ ret>d1 z well z p>tially de/roy1 ! vibrations4 ,9 a v]tical direction1 h[ev]1 ! rocks re/ firmly ^u "o ano!r1 & ?is gives measurable cont9uity1 ! only *ange be+ f "o lay] or k9d ( rock to ano!r4 ,x seems c]ta91 !re=e1 t ! v]tical compon5t ( ! seismic wave w be less damp$ & less ret>d$ 9 transmission ?an ! horizontal4 ,x w1 !re=e1 rea* ! surface soon] & w h ! great] effect on bodies at ! surface1 n only = ! reasons giv51 b also because x em]ges m ne>ly 9 ! l9e ( lea/ resi/ance & ( free/ projection4 ,on ?is acc\nt1 a second correction mu/ be add$ to ! correction = ela/icity1 & ?is mu/ fur!r r$uce appreciably ! fir/ e/imate ( ! dep? ( ! focus4 ,obs]vation %[s t 9 "s way a seismic wave becomes sep>at$ 9 transmission into portions ( diff]5t natures & spe$s1 b _! int]pretation is yet unc]ta94 ,^! sep>at$ portions probably consi/ ( ! compressional1 ! di/ortional1 & ! undulatory waves1 & p]haps ( refractions & reflections ( ^! 7see ,fig4 #ddh74 ,a mo/ important rec5t a*ievem5t is ! detection & inve/igation ( seismic tremors t appe> to h come ?r\gh ! e>?4 ,! transmission ( su* waves promises to reveal mu* relative to ! nature ( ! deep int]ior1 :5 en\gh data are ga!r$ to w>rant conclusions4 ,! rate ( propagation 9 ! c5tral p>ts is f\nd to be great] ?an 9 ! out] p>ts1 imply+ high ela/icity )94 ,! amplitude ( ! vibrations4--,f ! v disa/r\s effects ( sev]e e>?quakes1 x is natural to inf] t ! di/9ctive oscillations mu/ h l>ge amplitude1 b 9 fact x is ! sudd5ness ( ! vibration1 r ?an its l5g?1 t is effective4 ,in/rum5tal inve/igations indicate t ! oscillations1 aft] !y h left _! po9ts ( orig91 are usually only a fraction ( a millimet] 9 amplitude2 at mo/ !y seldom exce$ a few millimet]s4 ,a sudd5 %ock ) an amplitude ( #e or #f millimet]s is suffici5t to %att] a *imney4 ,x is true t e/imates assign+ amplitudes ( a foot or m h be5 made1 b _! correctness is op5 to s]i\s d\bt4 ,x %\ld be und]/ood t x is ! l5g? ( oscillation ( ! p>ticles ( ! subsurface rock transmitt+ ! vibrations t is ref]r$ to1 n ! movem5t ( ! free surface1 or ( objects on ! surface4 ,! ?r[ at & on ! surface is mu* great]4 ,j z a slight1 quick tap ( a hamm] on a floor is suffici5t to make a m>ble ly+ on x b\nd sev]al in*es1 s a suffici5tly sudd5 rise ( ! surface ( ! e>?1 ?\gh b a fraction ( an in*1 may project loose bodies _m feet4 ,illu/ration3 ,fig4 #ddg4--;,illu/ration ( ! de/ructive effects ( ! ,*>le/on e>?quake1 %[+ def9ite direction ( ?r[4 7,w4 ,j4 ,mc,gee47 ,de/ructive effects4--,! int]pretation ( ! disa/r\s results ( e>?quake %ocks has1 !re=e1 its key 9 ! sudd5ness & /r5g? ( r m9ute vibrations ( ! e>?-matt]1 b x is also dep5d5t on ! fre$om ( motion ( ! bodies affect$4 ,! rocks ( ! deep] zones1 :]e ! matt] is s5sibly cont9u\s1 transmit ! seismic vibrations )\t appreciable disruptive effect1 s f> z kn[n1 ?\gh ! orig9 ( crevices has be5 assign$ to ?is cause2 b bodies at ! surface are fractur$1 ov]turn$1 & hurl$ f _! places4 ,! reason is d\btless ?is3 ,)9 a great mass firmly held 9 place by cohesion & pressure on all sides1 ! =w>d motion ( a p>ticle develops an equal ela/ic resi/ance1 & x is quickly ?r[n back aga9 & ! wave passes on4 ,at ! surface1 :]e bodies are fre] to move1 ! /roke ( ! vibration projects ! body1 & s1 in/ead ( vibratory resili5ce1 ! *ief en]gy is conv]t$ into mass-motion4 ,! tap ( a hamm] s5ds an almo/ imp]ceptible vibration along ! floor1 b ?is vibration may ?r[ a glass ball1 b5ea? :i* x runs1 into ! air4 ,s ! m9ute vibrations ( e>?-matt] may travel miles f _! orig9 ?r\gh cont9u\s sub/ance ) little result1 & !n s sudd5ly ?ru/ a loose body on ! surface1 or ! base ( a column1 or ! f\ndation ( a h\se1 z to rack x ) diff]5tial /ra9s1 or ev5 to hurl x to de/ruction4 ,s1 too1 e>?-waves /rik+ ! sea-bord] may ?ru/ ! wat]s (f %ore by _! sudd5 impact1 & ! reaction may develop a wave :i* ov]:elms ! coa/4 ,su* waves may d\btless arise f a sudd5 /roke ( seismic vibrations on ! sea-bottom4 ,! great gap+ fissures t sometimes op5 dur+ e>?quakes occur (t5e/ :]e ! surface on "o side is less well support$ ?an on ! o!r1 z on a slope1 or ne> a bluff-face or a riv]-*annel4 ,:5 9 su* situations ! e>? is once sudd5ly =c$ 9 ! direction ( lea/ resi/ance1 x is n always met by suffici5t ela/ic resi/ance to ?r[ x back4 ,sometimes1 h[ev]1 !re is an ela/ic return1 & ! fissure closes =cibly an in/ant aft] x is op5$4 ,direction ( ?r[4--,imm$iately above ! po9t ( orig91 te*nically ! epic5trum or epi-focal po9t1 bodies are project$ upw>ds4 ,:5 cru%+ takes place 9 su* a case1 x is due to ! up?ru/ or to ! return d[nfall4 ,at "o side ( ! epic5trum ! ?ru/ is oblique 9 v>i\s degrees1 & is usually m de/ructive1 if n too f> f ! epic5trum4 ,! de/ructiv5ess commonly increases = a c]ta9 di/ance f ! epi-focal po9t1 & !n dim9i%es4 ,"u ideal conditions1 ! greate/ effects are f\nd :]e ! vibration em]ges at an angle ( ab\t #de1 b v>i\s influ5ces modify ?is result4 ,l9es drawn ?r\gh po9ts ( equal effect 7isoseismals7 are n usually regul> circles or ellipses ab\t ! epic5trum1 z !y w\ld be "u ideal conditions4 ,! v>i\s div]g5cies repres5t diff]5ces ( effective ela/icity1 ( surface1 & ( o!r influ5ces4 ,z mo/ e>?quakes orig9ate f l9es1 planes1 or masses1 r ?an po9ts1 !re are d\btless diff]5ces ( int5sity ( vibration at diff]5t po9ts on ! l9es1 planes1 or areas ( orig91 & ^! diff]5ces introduce inequalities 9 propagation & 9 surface effects4 ,illu/ration3 ,fig4 #ddh4--;,illu/rations ( ! records made by e>?quake tremors aft] di/ant transmission ?r\gh ! e>?4 ,! f\r diagrams repres5t ! same set ( tremors z receiv$ at ,%ide1 ,kew1 ,bid/on1 & ,ed9burgh 9 ,great ,brita94 ,! movem5t 0 f left to "r4 7,milne47 ,rate ( propagation4--,! progress ( a seismic wave v>ies v greatly4 ,bo? exp]im5tal te/s & natural obs]vations give v discordant results4 ,at pres5t1 !y ju/ify only ! broad /atem5t t ! velocity ( propagation v>ies f sev]al hundr$s to sev]al ?\s&s ( feet p] second at ! surface4 ,! rate seems to be great] = /rong vibrations ?an = weak ones1 & h5ce x is fa/] ne> ! orig9 ?an f>!r away4 ,! /r5g? ( a vibration dies away1 !oretically1 accord+ to ! inv]se squ>e ( ! di/ance f ! po9t ( orig94 ,practically !re is to be add$ to ?is ! p>tial de/ruction ( ! vibrations by conv]sion into o!r =ms ( motion4 ,sequ5ces ( vibrations4--,ne> ! s\rce1 ! ma9 %ocks are apt to come sudd5ly & to be foll[$ by m9or tremors4 ,at a di/ance !re are usually 8prelim9>y0 vibrations foll[$ by ! ma9 tremors1 & ^! by o!rs ( gradually dim9i%+ value4 ,?is developm5t is assign$ to diff]5t rates ( propagation1 & to refractions & reflections n unlike ! prolongation ( ?und] 7see ,fig4 #ddh74 ,?is deploym5t ( ! vibrations is notably develop$ 9 ! %ocks t pass long di/ances ?r\gh ! e>?4 ,! vibrations ( ! fir/ phase are reg>d$ z compressional1 ^? ( ! second z di/ortional1 :ile ! l>ge/ oscillations :i* arise /ill lat] p]haps come ar\nd ! surface1 & may be undulatory1 ?\gh _! nature is n yet det]m9$4 ,!re is (t51 h[ev]1 a true succession ( orig9al %ocks caus$ by a succession ( slips or ruptures at ! s\rce4 ,sometimes ^! are exce$+ly p]si/5t1 runn+ ?r\gh days1 weeks1 or ev5 mon?s4 ,9 su* cases a sl[ fault+ is probably 9 progress1 & little slips & /ops foll[ 9 close succession4 ,9 "o in/ance z _m z #fjj %ocks 9 t5 days h be5 report$4#bbf ,gase\s emanations4--,vapors & gas frequ5tly issue f e>?quake r5ts1 & are popul>ly made to s]ve z causes1 b !y are usually m]ely ! e>? gases t are p]mitt$ to escape by ! r5d+ ( ! gr\nd1 or are =c$ out by readju/m5t ( ! %ak5 b$s4 ,l o!r subt]ranean gases1 !y are (t5 sulphur\s1 & !y are sometimes hot1 especially 9 volcanic regions4 ,:]e ! %ocks are connect$ ) eruptions1 ! gases may be truly volcanic4 ,di/ribution ( e>?quakes4--,ov] l>ge portions ( ! globe1 sev]e e>?quakes are exce$+ly r>e1 b 9 c]ta9 regions !y are un=tunately frequ5t4 ,= ! mo/ "p1 ^! are volcanic di/ricts1 b ?is is by no means a univ]sal relation4 ,e>?quakes & volcanoes are only 9 "p associates4 ,9 g5]al1 x may be said t e>?quakes are frequ5t :]e geologic *anges are 9 rapid progress1 z along belts ( "y m\nta9s1 :]e ! /resses are n yet adju/$1 or at ! m\?s ( great /reams1 :]e deltas are accumulat+1 or ab\t volcanoes1 :]e temp]atures & /ra9s are *ang+1 or on ! great slopes1 p>ticul>ly ! subm>9e slopes1 :]e readju/m5ts 9 response to inequalities ( surface /ress are 9 progress4 ,n a few1 h[ev]1 occur :]e ! special occasion is n at all obvi\s4 ,! ,geologic ,effects ( ,e>?quakes4 ,e>?quakes are ( mu* less importance1 geologically1 ?an _m g5tl] movem5ts & activities4 ,disa/r\s z !y sometimes are to human affairs1 !y leave few di/9ct & readily id5tifiable m>ks :i* are m ?an tempor>y4 ,fractur+ ( rock4--,dur+ ! passage ( notable e>?quake waves1 ! solid rock is probably (t5 fractur$ 7see p4 #eji71 ?\gh :]e x is cov]$ by deep soil ! fractures are r>ely obs]vable at ! surface4 ,else:]e ! crevices are readily se51 especially if !y gape4 ,9 a few in/ances surface-rock has be5 se5 to be ?or\ghly %att]$ aft] ! passage ( an e>?quake1 z 9 ! ,concepcion e>?quake ( #ahce4bbg ,jo9ts :i* 7 be=e clos$ are (t5 op5$ dur+ an e>?quake4 ,?us 9 nor!rn ,arizona1 n f> f ,canyon ,diablo1 !re is a crevice traceable = a consid]able di/ance1 :i* is said to h be5 op5$ dur+ an e>?quake4 ,locally1 x gaps sev]al feet4 ,o!r notable e>?quake fissures h be5 record$ 9 ,india1#bbh ,japan1 & ,new ,zeal&4 ,dur+ an e>?quake :i* %ook ! ,s\? ,isl& ( ,new ,zeal& 9 #ahdh1 8a fissure 0 =m$ av]ag+ #ah in*es 9 wid?1 & traceable = a di/ance ( #fj miles1 p>allel to ! axis ( ! adjac5t m\nta9 *a940#bbi ,! developm5t ( fractures or ! op5+ ( jo9ts is sometimes accompani$ by fault+4 ,?is 0 ! case 9 ,japan dur+ ! e>?quake ( ,octob] #bh1 #ahia1 :5 ! surface on "o side ( a fissure1 :i* c\ld be trac$ = #dj miles1 sank #b to #bj feet4 ,9 ?is case !re 0 also notable horizontal displacem5t1 ! ea/ wall ( ! fissure be+ ?ru/ locally z mu* z #ac feet to ! nor?4#bcj ,*anges ( surface4--,circul> surface op5+s or bas9s are sometimes develop$ dur+ e>?quakes4 ,?is 0 ! case dur+ ! ,*>le/on e>?quake ( #ahhf1bca & simil> effects h be5 not$ else:]e4 ,^! op5+s (t5 s]ve z av5ues ( escape = gr\nd-wat]1 gases1 & vapor4 ,!y are commonly suppos$ to be ! result ( ! collapse ( cav]ns1 or o!r subt]ranean op5+s1 ! collapse (t5 caus+ ! =cible ejection ( wat]4 ,su* op5+s are likely to be =m$ only :]e ! surface mat]ial is incoh]5t4 ,s&/one dikes 7p4 #ead7 may p]haps be associat$ 9 orig9 ) e>?quakes4 ,e>?quakes are likely to dislodge masses ( rock 9 un/able positions1 z on slopes or cliffs4 ,!y may also occasion slumps & l&slides4#bcb ,effects on dra9age4--,! fractur+ ( ! rock may int]f]e ) ! movem5t ( gr\nd-wat]4 ,aft] new cracks are develop$1 or old ones op5$ or clos$1 ! movem5t ( gr\nd-wat] adapts itself to ! new conditions4 ,x foll[s t spr+s sometimes cease to fl[ aft] an e>?quake1 :ile new ones break out :]e !re _h be5 none be=e4 ,! "* ( ! wat] ( spr+s is sometimes *ang$1 presumably because x comes f diff]5t s\rces aft] ! e>?quake4 ,jo9ts may be s wid5$ z to int]cept rivulets1 & ! wat]s ?us int]cept$ may cause ! fur!r enl>gem5t ( ! op5+4 ,illu/rations ( ?is sort are furni%$ by ! e>?quakes ( ! ,mississippi valley 7,lat4 #cf to #ch7 9 #ahaa-ab4 ,:]e faults accompany e>?quakes1 !y occasion ponds or falls :]e !y cross /reams4 ,illu/rations ( bo? 7 furni%$ by ! ,*$rang ,riv] ( ,india aft] ! e>?quake ( #ahig4bcc ,effects on /&+ wat]4--,"s ( ! mo/ de/ructive effects ( e>?quakes are felt along ! bord]s ( ! sea4 ,?us ! great sea-wave ( ! ,lisbon e>?quake 7#agee7 & t ( ! e>?quake :i* affect$ ! coa/s ( ,ecuador & ,p]u 9 #ahfh are examples4 ,su* waves h be5 kn[n to advance on ! l& z walls ( wat] #fj feet 9 height4 ,!y are mo/ de/ructive along l[ coa/s1 = "h ! wat] may sweep mu* m ext5sively ov] ! l&4 ,! great loss ( life dur+ an e>?quake has usually be5 ! direct result ( ! great waves4 ,lakes are also affect$ by e>?quakes1 _! wat]s sometimes ris+ & fall+ = sev]al h\rs aft] ! initial di/urbance1 b lake-waves are mu* feebl] ?an ^? ( ! sea1 & are n (t5 de/ructive4 ,e>?quake %ocks are sometimes rem>kably de/ructive to ! life ( lakes & seas4 ,?us dur+ ! ,indian e>?quake ( #ahig1 8fi%es 7 kill$ 9 myriads z by ! explosion ( a dynamite c>tridge 444 & = days aft] ! e>?quake1 ! riv] 7,sumes>i7 0 *ok$ ) ?\s&s ( dead fi% 444 & two float+ c>casses ( ,gangetic dolph9s 7 se5 :i* _h be5 kill$ by ! %ock40#bcd ,?is :olesale de/ruction ( life is ( int]e/1 s9ce ! surfaces ( lay]s ( rock1 (t5 ( great age1 are sometimes cov]$ ) fossils ( fi% or o!r animal =ms1 s num]\s & s pres]v$ z to indicate t ! animals 7 kill$ sudd5ly & 9 great numb]s1 & _! bodies quickly buri$4 ,x has be5 sugge/$ t su* rock surfaces may be memorials ( anci5t e>?quake %ocks4#bce ,*anges ( level4--,p]man5t *anges ( level sometimes accompany an e>?quake4 ,?us aft] ! e>?quake ( #ahbb 8! coa/ ( ,*ili = a long di/ance 0 said to h ris5 #c or #d feet40#bcf ,simil> results h occurr$ on ! same coa/ at o!r times1 & on o!r coa/s at v>i\s times4 ,depression ( ! surface is p]haps ev5 m common ?an elevation4 ,?us on ! coa/ ( ,india all except ! high] p>ts ( an area #fj squ>e miles 9 ext5t 7 sunk bel[ ! sea dur+ an e>?quake 9 #agfb4 ,widespread depression 9 ! vic9ity ( ! ,mississippi 9 ,miss\ri1 ,arkansas1 ,k5tucky1 & ,t5nessee accompani$ ! e>?quakes ( #ahaa & #ahab4 ,"s ( ! depress$ areas 7 conv]t$ into m>%es1 :ile o!rs became ! sites ( p]man5t lakes4 ,reelfoot ,lake1 ma9ly 9 ,t5nessee1 is an example4 ,*ange ( level is involv$ :]ev] !re is fault+1 & fault+ is probably r common 9 connection ) e>?quakes4 ,*anges ( level are n conf9$ to ! l&4 ,:]e e>?quake di/urbances affect ! sea-bottom 9 regions ( telegraph cables1 ! cables are (t5 brok54 ,9 su* cases notable *anges h sometimes be5 discov]$ & record$ :5 ! cables 7 repair$4 ,/rik+ examples are furni%$ by ! region ab\t ,greece4#bcg ,9 "o in/ance 7#ahgc7 ! repair+ vessel f\nd ab\t #bjjj feet ( wat] :]e ab\t #adjj feet exi/$ :5 ! cable 0 laid4 ,9 ano!r in/ance 7#ahgh7 ! bottom 0 8s irregul> & unev5 = a di/ance ( ab\t two miles1 t a det\r 0 made & ! cable l5g!n$ by five or six miles40 ,9 /ill ano!r case 7#ahhe7 ! repair+ vessel f\nd a 8diff]5ce ( #aejj feet betwe5 ! b[ & /]n s\nd+s40 ,^! records po9t to sea-bottom fault+ on a l>ge scale4 ,x is probably no ne>] ! tru? to say t *anges ( level result f e>?quakes ?an to say t e>?quakes result f *anges ( level4 ,! two classes ( ph5om5a are probably to be ref]r$ to a common cause4#bch ,,sl[ ,,massive ,,movem5ts4 ,x is a f> cry f ! int5se & inconceivably rapid oscillations ( ! e>?quake1 to ! excessively sl[ subsid5ces ( cont95ts1 or ev5 ! sl[ wr9kl+ ( m\nta9 folds4 ,n infrequ5tly riv]s we> d[n _! *annels across a m\nta9 range z fa/ z x rises a?w>t !m4 ,! movem5ts ( cont95ts are ev5 m delib]ate4 ,b1 f> ap>t z ^! contra/$ movem5ts are1 9 rate & me?od1 !y are associat$ 9 ultimate causation1 & ! e>?quake %ock is (t5 m]ely an incid5t 9 ! =mation ( a m\nta9 range or 9 ! subsid5ce ( a cont95t4 ,! great movem5ts are usually class$ 7#a7 z cont95t-mak+ 7epeirog5ic7 & 7#b7 m\nta9-mak+ 7orog5ic74 ,!y may also be class$ z 7#a7 v]tical movem5ts & 7#b7 horizontal movem5ts1 & dynamically1 z 7#a7 ?ru/ movem5ts & 7#b7 /ret*+ movem5ts4 ,x is to be und]/ood t ^! di/9ctions are little m ?an analytical conv5i5ces1 = cont95tal movem5ts are (t5 at ! same "t m\nta9-mak+ movem5ts2 v]tical movem5ts are usually involv$ 9 horizontal movem5ts1 & /ret*+ usually takes "p 9 ! processes 9 :i* ?ru/ pr$om9ates1 & vice v]sa4 ,b :]e "o phase greatly prepond]ates1 x may conv5i5tly give "n to ! :ole4 ,pres5t movem5ts4--,critical obs]vations on seacoa/s %[ t "s %ores are sl[ly ris+ & "s sl[ly s9k+ relative to ! ocean-level4 ,we d n c]ta9ly "k :at _! movem5ts are relative to ! c5t] ( ! e>?2 v possibly all may be s9k+1 "o set fa/] ?an ! o!r1 ! ocean-surface also go+ d[n at an int]m$iate rate4 ,!oretically1 all might possibly be ris+1 "o set fa/] ?an ! o!r1 ! ocean also ris+ at an int]m$iate rate1 ?\gh ?is is extremely improbable4 ,"o set may be actually ris+ relative to ! c5t] ( ! e>?1 & ! o!r s9k+1 :ile ! ocean-level is /ation>y1 or ne>ly s4 ,?is is ! way 9 :i* we are accu/om$ to int]pret !m4 ,a g5]al %r9kage ( ! e>?1 h[ev]1 is probably go+ on1 c>ry+ d[n l&-surface & sea-surface4 ,x has be5 urg$ by ,suess#bci t ! g5]al %r9kage is s great t ! local upw>d w>p+s & fold+s nev] equal x1 & t ! real movem5ts are all d[nw>d1 ?\gh 9 diff]5t degrees4 ,?is is probably ! g5]al fact at lea/4 ,ov] aga9/ ?is is ! popul> disposition to reg>d e>? movem5ts g5]ally z 8upheavals40 ,!re is also a pr$ilection = reg>d+ ! rigid l& z mov+ & ! mobile sea-level z fix$4 ,9 reality1 ! sea is an extremely adaptive body t settles into ! irregul> holl[s ( ! li?osph]e1 & is %ift$ ab\t ) e w>p+ ( ! latt]4 ,:atev] *ange affects ! capacity ( its depressions affects also ! sea-level4 ,if !y are increas$1 ! sea settles m deeply into !m2 if !y are decreas$1 ! sea spreads out m widely on ! bord]s ( ! l&4 ,! "o ?+ t gives a measure ( /ability to ! sea-level is ! fact t all ! great bas9s are connect$1 & s an av]age is ma9ta9$4 ,a w>p+ d[n 9 "o "p ( ! sea-bottom may be (fset by an upw>d w>p+ some:]e else 9 ! #gb ( ! e>?'s surface cov]$ by ! ocean1 & s x is only ! sum total ( all *anges 9 ! sea-bottoms & bord]s t effects ! common level4 ,?us x happ5s t1 not)/&+ its in/ability & its complete subord9ation to ! li?osph]e1 ! sea-level is ! mo/ conv5i5t basis ( ref]5ce1 & has become ! accept$ datum-plane4 ,if !re 7 "s available mode ( measur+ ! di/ance ( po9ts f ! c5t] ( ! e>?1 x w\ld give absolute data & absolute t]ms1 & w\ld reveal mu* t is n[ unc]ta9 respect+ ! real movem5ts ( ! surface4 ,= conv5i5ce1 h[ev]1 s9ce absolute t]ms are impracticable1 ! ord9>y language ( geology1 :i* repres5ts movem5ts z upw>d & d[nw>d1 accord+ to _! relations to ! sea-level or to ! av]age surface1 w be employ$4 ,not)/&+ ?is concession to conv5i5ce 9 ! use ( t]ms1 x is ( ! greate/ importance to =m1 & to con/antly reta91 true fundam5tal views4 ,fundam5tal conceptions4--,! exi/5ce ( any l& at all is dep5d5t on ! inequalities ( ! surface & ( ! d5sity ( ! li?osph]e1 = if x 7 p]fectly sph]oidal & equid5se1 ! hydrosph]e w\ld cov] x completely to a dep? ( ab\t two miles4 ,n only are inequalities necess>y to ! exi/5ce ( l&1 b ^! inequalities mu/ be r5ew$ f "t to "t1 or ! l& area w\ld soon1 geologically speak+1 be cov]$ by ! sea4 ,! r5ewal has be5 made aga9 & aga9 9 geological hi/ory by movem5ts t h increas$ ! inequalities 9 ! surface ( ! li?osph]e4 ,) ea* su* movem5t1 app>5tly1 ! oceans h )drawn m completely )9 ! bas9s1 & ! cont95ts h /ood =? m broadly & relatively high]1 until aga9 worn d[n4 ,?is r5ewal ( inequalities appe>s to h be51 9 its great features1 a p]iodic movem5t1 recurr+ at long int]vals4 ,9 ! int]v5+ times1 ! sea has crept out ov] ! l[] p>ts ( ! cont95ts1 mov+ on /eadily & sl[ly t[>d _! complete subm]sion1 :i* w\ld inevitably h be5 atta9$ if no int]ruption _h *eck$ & rev]s$ ! process4 ,^! are ! great movem5ts ( ! e>?1 & 9 !m lies1 we believe1 ! s\l ( geologic hi/ory & ! basis = its gr& divisions4 ,! reasons = ?is w appe> z ! hi/ory is foll[$1 & its mo/ pot5tial ag5cies are se5 unfold+ !mselves4 ,at ! same "t1 !re h be5 num]\s m9or surface movem5ts 9 almo/ con/ant progress4 ,:ile ^! two classes ( movem5ts h be5 associat$1 & are p]haps due 9 ! ma9 to ! same causes1 !y are suffici5tly diff]5t 9 "s ( _! dynamic aspects to be sep>at$ 9 treatm5t4 ,ne>ly ,con/ant ,small ,movem5ts4 ,innum]able g5tle w>p+s h affect$ ne>ly e portion ( ! surface ( ! globe at ne>ly all /ages ( its hi/ory4 ,n only dur+ ! p]iods ( great movem5ts 7 !re c\ntless m9or & g5tl] movem5ts1 b at times ( relative quiesc5ce !re 7 sl[ swell+s & sagg+s ( ! surface ( ! li?osph]e4 ,!y sometimes affect$ small areas & sometimes l>ge ones1 & !y 7 sometimes ( upw>d phase & sometimes ( d[nw>d4 ,!y 7 ! imm$iate ag5cies 9 locat+ & controll+ ! deposition ( /ratifi$ rocks1 ?\gh !y re/ back on ! great movem5ts = _! work+ conditions4 ,v sl[ s9k+s ( sea-bord]s h p]mitt$ deposition to g on 9 %all[ wat] = long p]iods )\t be+ int]rupt$ by ! local fill+ ( ! sea4 ,v sl[ swell+s ( l& tracts1 relative or absolute1 h p]mitt$ erosion to supply mat]ial = su* s$im5tation = long p]iods )\t exhau/+ ! s\rces4 ,v sl[ upw>d w>p+s 9 "o region & d[nw>d w>p+s 9 ano!r h %ift$ ! bord]s ( ! l& & sea1 & ) !m ! areas ( erosion & deposition4 ,?us h aris5 ov]laps & uncon=mities ( /rata & div]sities 9 _! di/ribution f /age to /age4 ,su* movem5ts may h am\nt$ to a few in*es1 or a few feet1 or a few fa?oms p] c5tury4 ,d[nw>d movem5ts h sometimes affect$ a consid]able section ( a cont95t1 lett+ 9 a %all[ epicont95tal sea ^u x1 su*1 = example1 z ! ,nor? ,sea ^u ! nor?we/]n bord] ( ! cont95t ( ,europe1 & ,hudson ,bay ^u ! nor!a/]n "p ( ,nor? ,am]ica4 ,simil> movem5ts seem to h ext5d$ ! seas ev5 m widely ^u ! surface ( ! l& 9 times pa/1 z atte/$ by ! great transgressions ( ! ocean-bord]s & ! great epicont95tal spread ( /rata4 ,not)/&+ _! great bread?s1 ! epicont95tal seas 7 g5]ally %all[4 ,simil> g5tle w>p+s ( upw>d phase rescu$ ! bottoms ( %all[ seas f subm]sion1 & inaugurat$ erosion2 or !y b[$ base-level$ l&s upw>d1 & rejuv5at$ _! /reams & inaugurat$ a new cycle ( d5udation4 ,(t5 !y connect$ cont95ts previ\sly sep>at$ by %all[ /raits1 & ?us inaugurat$ int]-cont95tal migrations ( l& life1 :ile !y /opp$ int]-oceanic migration4 ,! g5tl5ess & frequ5cy ( ^! movem5ts is atte/$ by ! "* ( ! s$im5ts & by _! relations to "o ano!r1 z w be se5 9 ! /udy ( ! s$im5t>y s]ies4 ,reciprocal features4--,^! m9or w>p+s %[ a notable t5d5cy to be reciprocal4 ,if "o area is b[$ up1 ano!r ne> by is b[$ d[n4 ,if ! cont95ts settle1 ! oceans rise on _! bord]s4 ,if ! l& is cut d[n1 ! sea is fill$ up4 ,!re is an important phase ( ?is des]v+ especial note4 ,c]ta9 tracts h be5 sl[ly b[$ upw>ds into long l& swells1 ! /reams be+ rejuv5at$ & degradation ha/5$4 ,adjac5t tracts h be5 sl[ly b[$ d[nw>ds into long p>allel tr\ghs :i* receiv$ ! wa% f ! adjac5t swells1 & ?us became tracts ( exceptional s$im5tation4 ,su* a tract ( p>allel swell & sag1 if our int]pretation be correct1 develop$ along ! ,atlantic bord] ( ,nor? ,am]ica 9 ! ,paleozoic era4 ,by ! sl[ upw>d w>p+ ( ! swells1 ! fe$+-gr\nds ( ! /reams 7 ma9ta9$1 & ! sags 7 fill$ ab\t z fa/ z !y sank4 ,?us a great dep? ( s$im5t 0 laid d[n 9 ! c\rse ( an era measur$ by millions ( ye>s4 ,s 9 o!r regions1 especially ne> ! bord]s ( ! cont95ts1 !re h be5 simil> reciprocal movem5ts1 giv+ at once fe$+-gr\nds = ! /reams & lodgm5t-gr\nds = ! s$im5ts1 side by side 9 p>allel belts4 ,x is a common view t ^! belts ( deep s$im5tation 7 ! =]unn]s ( m\nta9 =mation1 & t !y det]m9$ ! =mation ( ! m\nta9s4 ,9 view ( ! gr\nds = d\bt+ ! effici5cy ( s sup]ficial an ag5cy 9 m\nta9 =mation1 :i* w appe> z we g on1 x may be well to hold ?is view 9 abeyance1 & to dwell on ! reciprocal nature ( ! action1 9 :i* ! upw>d b[+ t gave ! fe$+-gr\nds is z vital a factor z ! sagg+ t accommodat$ ! s$im5tation4 ,x is important to recognize t 9 s f> z ! cru/ 0 weak en\gh to yield to ^! g5tl] =ces1 x 0 n /rong en\gh to accumulate ! great /resses necess>y to =m m\nta9 ranges1 & fur!r1 t 9 s f> z ! /resses 7 eas$ by ! g5tle w>p+1 !y c\ld n be accumulat$ = ! lat] "w ( m\nta9-fold+4 ,x is nev]!less probable t ! conditions :i* locat$ ! g5tle swell+ & sagg+ also locat$ ! m\nta9-fold+4 ,! ,great ,p]iodic ,movem5ts4 ,m\nta9-=m+ movem5ts4--,along c]ta9 tracts1 usually ne> ! bord]s ( ! cont95ts1 & at c]ta9 times1 usually sep>at$ by long int]vals1 ! cru/ 0 fold$ into gigantic wr9kles1 & ^! con/itute ! *ief type ( m\nta9s1 ?\gh n ! only type4 ,! *>act]i/ic =ce 9 ?is fold+ 0 lat]al ?ru/4 ,! /rata 7 n only ar*$1 b (t5 closely fold$1 & sometimes int5sely crumpl$4 ,9 extreme cases1 l ! ,alps1 ! folds fl>$ out above1 giv+ ov]turn dips & rev]s$ /rata1 z illu/rat$ 9 ! *apt] on ,/ructural ,geology1 pp4 #eja-eaa4 ,9 ^! cases !re 0 an upw>d z well z a horizontal movem5t1 = ! folds !mselves 7 lift$2 b ! horizontal ?ru/ s mu* prepond]at$1 & 0 s mu* ! m rem>kable1 t ! upw>d movem5t 0 ov]%ad[$4 ,x is well to note1 h[ev]1 t ^! m\nta9 ranges are crumpl$ outw>d & n inw>d1 z might be expect$ if !y result$ simply f ! %r9kage ( ! "u side ( a ?9 %ell4 ,! folds are sometimes ne>ly upright & symmetrical1 & sometimes incl9$ & asymmetrical1 z illu/rat$ 9 ! *apt] ref]r$ to4 ,:]e ! folds lean1 ! inf]5ce has be5 drawn t ! active ?ru/ came f ! side ( ! g5tl] slope1 ! folds be+ pu%$ ov] t[>d ! resi/+ side1 & ?is seems to be commonly true4 ,! orig9al attitude ( ! b$s1 h[ev]1 has mu* to d ) ! "* ( ! folds4#bdj ,by a slight *ange 9 ! mode ( ?ru/1 %eets ( pap] may be s pu%$ z to lean =w>d or backw>d at pleasure4 ,! lean+ ( ! folds seems1 !re=e1 a d\btful crit]ion = det]m9+ ! direction ( ! active movem5t4 ,m\nta9s ( ! ?ru/ type usually consi/ ( a s]ies ( folds ne>ly p>allel to ea* o!r1 ! :ole =m+ an anticl9orium4 ,illu/ration3 ,fig4 #ddi4--,! great ,eurasian m\nta9 tract4 ,jones ,relief ,globe4 7,photo4 by ,r4 ,t4 ,*amb]l947 ,di/ribution ( fold$ ranges4--,! prevail+ location ( ?is class ( m\nta9s is s g5]ally ne> ! bord]s ( ! cont95ts t ! relation is probably significant4 ,dana#bda long ago call$ att5tion to ! fact t ! greate/ m\nta9 ranges /& opposite ! greate/ ocean-bas9s1 & he connect$ ! elevation ( ! "o ) ! depression ( ! o!r4 ,"o ( ! mo/ notable exceptions to ?is relation is ! complex sy/em ( s\!rn ,europe1 f ! ,pyr5ees to ! ,caucasus1 & ano!r is ! ,altai & connect$ ranges 7,fig4 #ddi74 ,! ,urals & n a few m9or ranges are also exceptions4 ,x is probably bett] to reg>d ! crumpl$ tracts z ly+ on ! bord]s ( great segm5ts ( ! e>? t act$ ess5tially z units1 & to reg>d ! relation%ip to ! sea z a co9cid5ce t is only 9 "p causal4#bdb ,plateau-=m+ movem5ts4--,ano!r lead+ phase ( cru/al movem5t is ! settl+ or ris+ ( great blocks ( ! cru/1 z ?\gh by v]tical r ?an horizontal =ce4 ,! we/]n plateau ( ,nor? ,am]ica & ! great plateau ( ,?ibet are gigantic examples4 ,! ,am]ican plateau embraces num]\s blocks :i*1 :ile !y h be5 elevat$ toge!r1 are individually tilt$ 9 _! own fa%ion4 ,at ! surface1 !y are sep>at$ by fault-planes1 b bel[1 "s ( !m1 & p]haps mo/ ( !m1 pass into flexures4 ,mo/ ( ^! flexures are ( ! monocl9al type 7p4 #eaf71 :i* dynamically means mu* ! same z a fault2 b "s ( !m may be ( ! compressive type1 )\t inconsi/5cy ) v]tical fault-relief above4 ,rese>* has n yet cov]$ ?or\ghly any great plateau1 & k ( ?is class ( movem5ts is less complete ?an t ( fold+ by lat]al ?ru/1 & x has a less ample place 9 ! lit]ature ( ! subject4 ,! plateau-=m+ movem5ts are1 h[ev]1 mu* m massive ?an ! m\nta9-fold+ movem5ts1 & /& next 9 magnitude to ! cont95t-=m+ movem5ts4 ,plateaus may be reg>d$ z small] plat=ms sup]pos$ on ! cont95tal plat=ms4 ,9 ! ocean-bas9s1 !re appe> to be rais$ plat=ms ( ! plateau type1 & !re are rem>kable 8deeps0 t h ! aspect ( anti-plateaus4 ,cont95t-=m+ movem5ts4--,true cont95t-=m+ movem5ts appe> to h ant$at$ ! e>lie/ kn[n s$im5ts4 ,z f> back z we c read ! s$im5t>y record1 ! cont95ts seem to h be5 well e/abli%$1 & !re is little evid5ce t !y h s9ce be5 fundam5tally *ang$4 ,x is true t "s v em95t geologi/s h r freely connect$ =mations on "o cont95t ) =mations hav+ simil> faunas on an opposite cont95t1 by a hypo!tical conv]sion ( ! int]v5+ ocean-bottoms into l& or %all[ wat]2 b mo/ su* faunal relations c be expla9$ almo/ equally well by migration ar\nd ! coa/s1 or at mo/ by m]e ridge-connections4 ,! paucity1 if n total abs5ce1 ( abysmal deposits 9 ! /rata ( ! cont95ts1 tak5 ) ! p]si/5ce ( t]re/rial & coa/al faunas1 leaves little room = assign+ an int]*ange ( position betwe5 abysmal dep?s & cont95tal elevations1 & vice v]sa4 ,dynamic consid]ations also (f] grave difficulties4 ,! doctr9e ( ! p]si/5ce ( cont95ts probably ought n to be pu%$ s f> z to exclude %all[ wat]1 or ev5 l&1 connections betwe5 ,s\? ,am]ica1 ,ant>ctica1 ,au/ralia1 ,india1 & ,s\? ,africa1 directly or indirectly1 at c]ta9 /ages ( geological hi/ory4 ,)\t =m+ f9al conclusions z to ! measure ( ! *ange :i* ! cont95ts h suff]$ dur+ kn[n geological hi/ory1 x is safe to conclude t ! cont95ts & ocean-bas9s 7 9 ! ma9 =m$ v e>ly 9 ! e>?'s hi/ory1 & t subsequ5t *anges h consi/$ *iefly 9 ! fur!r s9k+ ( ! bas9s & ! fur!r protrusion ( ! l&1 save z ! latt] has be5 cut d[n by erosion4 ,incid5tally1 ! ocean-bas9s h probably be5 ext5d$ & ! cont95ts re/rict$4 ,on ! o!r h&1 ! cont95ts h be5 built out on _! bord]s by wa% f ! l&1 & ! wat]s ( ! ocean h be5 some:at lift$ by ! deposition ( s$im5t 9 _! bas9s4 ,x is e/imat$ t ! cutt+ away ( ! pres5t cont95ts1 & ! deposition ( ! mat]ial 9 ! ocean-bas9s1 w\ld raise ! sea-level ab\t #fej feet4 7,r4 ,d4 ,george47 ,relations ( ^! movem5ts 9 "t4--,! fold+ movem5ts seem to h _h extraord9>y preval5ce 9 ! e>lie/ ages1 = ! ,ar*ean rocks are almo/ univ]sally crumpl$1 & (t5 9 ! mo/ intricate fa%ion4 ,!re is no sign t ! fold+ 0 !n limit$ to ! bord]s ( ! cont95ts2 x seems r to h affect$ ! :ole cont95tal surface4 ,aft] ! beg9n+ ( ! well-kn[n s$im5t>y s]ies1 crumpl+ appe>s to h tak5 place *iefly at long int]vals1 ?us m>k+ (f great "t-divisions1 & to h be5 conf9$ at any giv5 /age to c]ta9 tracts1 *iefly on ! bord]s ( great segm5ts ( ! e>?'s cru/4 ,conc]n+ ! plateau-=m+ movem5ts 9 ! pa/1 k is v meag]1 z ! detection ( plateaus ( anci5t times is m difficult ?an ! detection ( folds4 ,g5tle w>p+s h app>5tly be5 9 progress at all times4 ,relations ( v]tical to horizontal movem5ts4--,! d[nw>d movem5ts are unque/ionably ! prim>y ones1 & ! horizontal ones are second>y & incid5tal4 ,! fundam5tal feature is d\btless c5tral cond5sation actuat$ by gravity1 & ! ma/] movem5ts are ! s9k+s ( ! ocean-bas9s4 ,! great p]iodic movem5ts t made m\nta9s & plateaus1 & *ang$ ! capacity ( ! ocean-bas9s1 probably />t$ ) ! s9k+ ( "p or all ( ! ocean-bottoms4 ,9 ! great] p]iodic movem5ts1 probably all ! bas9s p>ticipat$ m or less1 b "s seem to h be5 m active ?an o!rs4 ,= example1 9 ! la/ great m\nta9-mak+ p]iod1 ! ,pacific bas9 seems to h be5 m active ?an ! ,atlantic1 :ile 9 ! simil> great ev5t at ! close ( ! ,paleozoic1 ! opposite seems to h be5 true4 ,! squeez+ up ( ! cont95ts d\btless took place simultane\sly ) ! settl+ ( ! bas9s4 ,! true conception is p]haps t ! ocean-bas9s & cont95tal plat=ms are b ! surface =ms ( great segm5ts ( ! li?osph]e1 all ( :i* cr[d t[>d ! c5t]1 ! /rong] & heavi] segm5ts tak+ prec$5ce & squeez+ ! weak] & light] ones betwe5 !m4 ,! area ( ! m depress$ or ma/] segm5ts is almo/ exactly twice t ( ! protrud+ or squeez$ ones4 ,?is e/imate includes 9 ! latt] ab\t #aj1jjj1jjj squ>e miles n[ cov]$ ) %all[ wat]4 ,! volume ( ! hydrosph]e is a little too great = ! true bas9s1 & x runs ov]1 cov]+ ! bord]s ( ! cont95ts4 ,! am\nt ( ! ov]fl[ fluctuates f "t to "t1 & may be neglect$ 9 a /udy ( ! movem5ts & de=mations ( ! li?osph]e4 ,! squeez$ segm5ts4--,! great protrud+ segm5ts %[ a t5d5cy t[>d rude triangul>ity4 ,!y are 7#a7 ! ,eurasian1 n[ /rongly ridg$ on ! s\? & ea/1 & relatively flat on ! nor?we/2 7#b7 ! ,african1 r /rongly ridg$ on ! ea/1 b less abruptly elevat$ on ! we/ & nor?2 7#c7 ! ,nor? ,am]ican1 n[ /rongly ridg$ on ! we/1 m g5tly on ! ea/1 & relatively flat at ! nor? & 9 ! int]ior2 7#d7 ! ,s\? ,am]ican1 /rongly ridg$ on ! we/ & some:at on ! nor!a/ & s\!a/4 ,! =ego+ =m ! major gr\p4 ,! m9or gr\p embraces 7#e7 ! ,ant>ctic segm5t1 n z yet suffici5tly kn[n to be well def9$1 & 7#f7 ! ,au/ralian1 broadly r5i=m r ?an triangul>4 ,to ^! are p]haps to be add$ 7#g7 ! l>gely subm]g$ plat=m t /ret*es f ,sumatra & ,java on ! s\?we/ to ! ,philipp9es on ! nor!a/1 & is atta*$ to ,india on ! nor?we/2 & 7#h7 ,gre5l&1 :i*1 ?\gh closely associat$ ) ,nor? ,am]ica1 is p>tially sep>at$ by a r deep depression4 ,! depress$ or ma/] segm5ts4--,! great sunk5 segm5ts %[ a t5d5cy to assume r\ghly polygonal1 r ?an triangul>1 =ms4 ,?is accords ) ! prim>y place assign$ !m1 s9ce1 9 a sph]ical surface divid$ into l>g] & small] segm5ts1 ! major p>ts %\ld be polygonal :ile ! m9or residual segm5ts are m likely to be triangul>4 ,! major segm5ts are 7#a7 ! ,pacific1 7#b7 ! ,indian1 7#c7 ! ,nor? ,atlantic1 & 7#d7 ! ,s\? ,atlantic4 ,^! =m ! pr9cipal gr\p1 :ile 7#e7 ! ,arctic deeps 7n includ+ ! %all[ epicont95tal portions71 7#f7 ! ,m$it]ranean1 7#g7 ! ,c>ibbean1 & 7#h7 ! *a9 ( deep pits betwe5 ! ,philipp9e ridge & ! ,bornean plat=m1 con/itute a subord9ate gr\p4 ,ea* memb] ( ! m9or gr\p is an irregul> *a9 ( depress$ pits r ?an a s+le cont9u\s deep1 unless ! ,arctic depression1 ( :i* little is n[ kn[n1 proves an exception4 ,!y lie betwe5 ! great] segm5ts at :at may be conceiv$ to be po9ts ( critical work+ relations1 & are accompani$ by small elevat$ blocks4 ,! ,c>ibbean1 ! ,m$it]ranean1 & ! ,bornean regions are ! seats ( ! greate/ pres5t volcanic & relat$ activities4 ,9 a g5]al view1 !re are !n f\r great sunk5 quadrilat]als & f\r great elevat$ triangles1 ) m9or att5dants 9 ea* class4 ,le/ fondness = simplicity & symmetry lead too f>1 we mu/ ha/5 to obs]ve t ! dim5sions are n alike 9 ei!r class4 ,! ,pacific segm5t is m ?an twice ! size ( any o!r bas9 segm5t1 & f\r times t ( ! ,nor? ,atlantic4 ,! ,eurasian triangle is m ?an twice ! av]age size ( ! o!r l& segm5ts1 & ne>ly ?ree times t ( ! ,s\? ,am]ican4 ,nor is !re any l>ge common divisor ( approximate accuracy4 ,?is is n at all /range if ! e>? be reg>d$ z a body ( some:at het]og5e\s composition :i* naturally %rank 9 r irregul> segm5ts4 ,on ! o!r h&1 ?is irregul>ity is some:at /range if ! e>? has evolv$ f a v homog5e\s & symmetrical1 primitive1 fluid /ate4 ,x is also a s]i\s consid]ation 9 any !ory t appeals to cry/all9e =m1 or analogy1 z 9 ! doctr9e ( a tetrah$ral e>?4 ,r\ghly approximat$ 9 millions ( squ>e miles1 ! major depress$ segm5ts are z foll[s3 ! ,pacific1 #fj1 ! ,indian1 #bg1 ! ,s\? ,atlantic1 #bd1 & ! ,nor? ,atlantic1 #ad1 leav+ #h = m9or depressions4 ,! elevat$ segm5ts are ,eurasian1 #bd1 ,african1 #ab1 ,nor? ,am]ican1 #aj1 & ,s\? ,am]ican1 #i1 leav+ #aj = ! m9or blocks4 ,if ^! segm5ts be reg>d$ z ! great integ]s ( body-movem5t1 two-?irds ( !m tak+ prec$5ce 9 s9k+ & ! o!r ?ird 9 suff]+ di/ortion1 x is easy to pass to ! conception ( sub-segm5ts1 mov+ some:at diff]5tly f ! ma9 segm5ts1 s z to aid 9 _! adju/m5t to "o ano!r1 & ?us to ! conception ( plateaus & deeps4 ,x is easy also to pass to ! conception ( mutual cr[d+ & crumpl+ at ! edges ( ^! segm5ts1 accompani$ by fracture & slipp+4 ,^! conceptions p]haps repres5t ! true relations betwe5 ! massive movem5ts ( ! abysmal & cont95tal segm5ts1 z well z ! less massive plateau-=m+ movem5ts & ! m\nta9-=m+ di/ortions4 ,! m\nta9s & plateaus are probably ! incid5tal results ( ! great abysmal & cont95tal readju/m5ts4 ,! great movem5ts are probably to be attribut$ to /resses t gradually accumulat$ until !y ov]came ! rigidity ( ! ?ick massive segm5ts involv$1 & =c$ a readju/m5t4 ,9 accumulat+ ^! /resses1 "s local yield+ on weak l9es & at special po9ts 0 an inevitable incid5t 9 di/ribut+ m equably ! accumulat+ /resses4 ,s1 also1 ! fir/ great readju/m5ts probably left _m local /ra9s & unequal /resses :i* gradually eas$ !mselves by w>p+s1 m9or fault+s1 etc41 s t "s m9or movem5ts 7 a natural sequ5ce ( ! great movem5ts4 ,b !re 7 d\btless _m local & sup]ficial causes1 su* z irregul> ga9s & losses ( heat1 regional load+ & unload+1 solution1 hydration1 etc41 t h caus$ local or regional movem5t1 & :i* h little to d ) ! great de=mations ( ! e>?'s body4 ,z impli$ above1 ! g5tle1 ne>ly con/ant movem5ts probably fall ma9ly into a diff]5t category f ! great p]iodic movem5ts4 ,bo? w be consid]$ fur!r4 ,! diff]5tial ext5t ( ! movem5ts4--,betwe5 ! highe/ elevation ( ! l& & ! l[e/ dep? ( ! ocean1 !re is a v]tical range ( ne>ly twelve miles4 ,!re may h be5 high] elevations1 relatively1 9 pa/ times1 b probably n deep] depressions2 & s1 if we assume t ! surface 0 once p]fectly sph]oidal1 ?is may be tak5 z a maximum expression ( diff]5tial movem5t1 n absolute v]tical movem5t4 ,f ! ,?ibetan plateau1 :]e a consid]able area exce$s ?ree miles 9 height1 to ! ,tusc>ora deep1 :]e a notable tract exce$s five miles 9 dep?1 ! range is eight miles1 :i* may fairly repres5t ! v]tical range ( r massive diff]5tial movem5t4 ,f ! av]age height ( ! cont95ts to ! av]age abysmal bottoms ( ! oceans ! range is ne>ly ?ree miles1 :i* may be tak5 z ! diff]5tial movem5t ( ! great segm5ts4 ,"u c]ta9 hypo!ses ( ! orig9 & e>ly hi/ory ( ! e>?1 to be sket*$ lat]1 ! surface is n assum$ to h be5 p]fectly sph]oidal orig9ally1 & h5ce ! pres5t irregul>ities d n necess>ily imply s great diff]5tial movem5t4 ,if ! protrud+ portions ( ! li?osph]e 7 grad$ d[n & ! bas9s grad$ up to a common level1 ?is level w\ld lie ab\t #ijjj feet bel[ ! ocean-surface4 ,?is equat$ level is ! be/ basis ( ref]5ce = relative segm5tal movem5ts4 ,ref]r$ to ?is datum plane1 ! cont95ts1 hav+ an area ab\t half z great z t ( ! ocean dep?s1 h be5 squeez$ up relatively ab\t two miles1 & ! bas9s h sunk ab\t "o mile f ! ideal common plane4 ,! total d[nw>d movem5t1 repres5t+ ! total %r9kage ( ! e>?1 is q unkn[n f obs]vation4 ,x is probably v mu* great] ?an ! diff]5tial movem5t1 z w appe> f !oretical consid]ations z we g on4 ,! ext5t ( ! lat]al movem5ts has a peculi> int]e/1 = x be>s !oretically on ! %r9kage ( ! e>?4 ,e mile ( desc5t ( ! cru/ repres5ts #f miles 7#f4bh7 %ort5+ ( ! circumf]5ce4 ,if ! v]tical movem5ts 7 limit$ to ! relative ones j nam$1 ! mile ( bas9 desc5t w\ld give b little m ?an #f miles ( surplus circumf]5ce = lat]al ?ru/ & crumpl+4 ,h[ f> does ?is g 9 expla9+ ! kn[n facts8 ,by measur+ ! folds ( ! ,alps1 ,heim has e/imat$ ! %ort5+ repres5t$ by !m to be #gd miles4#bdc ,claypole e/imat$ ! %ort5+ = ! ,appala*ians 9 ,p5nsylvania1 n includ+ ! cry/all9e belt on ! ea/1 at #df miles2#bdd ,mc,connel plac$ t ( ! ,l>amide range 9 ,briti% ,am]ica at #be miles1#bde & ,le,conte t ( ! ,coa/ range 9 ,cali=nia at #i to #ab miles4#bdf ,^! e/imates mu/ be correct$ = ! ?ick5+ & ?9n+ ( ! b$s 9 ! process ( fold+1 = ! composite "* ( ! folds1 & = ! effects ( %e>+ & fault+4 ,^! w 9 "p t5d to increase & 9 "p to decrease ! e/imates4 ,! fir/ effect ( horizontal ?ru/ is to close up all crevices & compact ! b$s z mu* z !y w /& )\t b5d+4 ,a "p ( ! unusual ?ickness :i* ! b$s ( fold$ regions commonly %[ is probably due to ?is edgewise compression4 ,9 exp]im5ts on artificial /rata made to illu/rate fold+s 7,fig4 #ddi;a71 ! ?ick5+ ( ! lay]s is a v appreciable "p ( ! process1 ?\gh probably natural b$s d n ?ick5 9 equal proportion4 ,aft] ! b$s h be5 closely fold$ & ! ?ru/ is a?w>t !m1 !y are ?9n$ & /ret*$ on ! limbs ( ! fold4 ,h[ f> ?is & o!r causes ( ext5sion (fset initial compression is undet]m9$1 & is diff]5tly e/imat$4 ,x seems highly probable f ! nature ( ! case t ! edgewise compression :i* result$ f su/a9+ ! full /ress be=e ! b$s b5t1 0 mu* great] ?an ! crosswise compression on ! limbs ( ! folds1 :i* came into action only aft] ! /ress _h be5 l>gely satisfi$ by fold+4 ,illu/ration3 ,fig4 #ddi;a4--,illu/rations ( ,willis' exp]im5ts 9 ! artificial repres5tation ( m\nta9 fold+4 ,! sections 7 =m$ ( lay]s ( wax ( diff]5t colors1 & 7 me*anically compress$ f ! "r4 ,! upp] section %[s ! orig9al /ate1 & ! (fsets ( ! succe$+ sections at ! "r indicate ! am\nt ( %ort5+4 7,?irte5? ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv47 ,:atev] ! correction1 & :atev] ! probable errors ( ! above e/imates1 ! am\nt ( %ort5+ involv$ 9 fold+ is l>ge4 ,! e/imates giv5 are m]ely ^? = c]ta9 p]iods ( fold+1 & repres5t only t portion ( ! compression ( ! circumf]5ce :i* 0 conc5trat$ 9 a giv5 m\nta9 range4 ,! :ole %ort5+ ( a circumf]5ce is to be f\nd by add+ toge!r all ! transv]se fold+s on a giv5 great circle1 foll[+ x ab\t ! globe at "r angles to a giv5 fold$ tract4 ,9 s do+1 x w be se5 t ! belt does n usually cross m ?an "o or two /rongly fold$ tracts ( ! same age1 f :i* x is inf]r$ t ! %ort5+ on ea* great circle 0 l>gely conc5trat$ 9 a few tracts runn+ at l>ge angles to ea* o!r1 to accommodate ! %r9kage ( ! globe 9 all directions4 ,if ! fold+ 9 a ma9 range cross+ any great circle is d\bl$1 x w probably repres5t r\ghly ! %ort5+ = t entire circle = t age4 ,if "o is dispos$ to m9imize ! am\nt ( fold+1 ! e/imate may p]haps be put r\ndly at #ej miles1 on an entire circumf]5ce1 = ea* ( ! great m\nta9-mak+ p]iods4 ,if1 on ! o!r h&1 "o is dispos$ to give ! e/imates a g5]\s figure s z to put explanations to ! sev]e/ te/1 he may p]haps fairly place ! %ort5+ at #ajj miles1 or ev5 m4 ,= ! :ole %ort5+ s9ce ,cambrian times1 p]haps twice ^! am\nts might suffice1 = :ile !re h be5 sev]al m\nta9-mak+ p]iods1 only ?ree are p]haps entitl$ to be put 9 ! fir/ ord]1 t at ! close ( ! ,paleozoic1 t at ! close ( ! ,mesozoic1 & t 9 ! late ,t]ti>y4 ,! %ort5+ 9 ! ,prot]ozoic p]iod 0 consid]able1 b is imp]fectly kn[n4 ,! ,ar*ean rocks suff]$ great compression 9 _! own times1 & probably %>$ 9 t ( all lat] p]iods1 & if _! %ort5+ c\ld be e/imat$ closely1 x might be tak5 z cov]+ ! :ole4 ,assum+ ! circumf]5tial %ort5+ to h be5 #ej miles dur+ a giv5 great m\nta9-fold+ p]iod1 ! appropriate radial %r9kage is #h miles4 ,= ! m g5]\s e/imate ( #ajj miles1 x is #af miles4 ,if ^! e/imates be d\bl$ = ! :ole ( ! ,paleozoic & lat] eras1 ! radial %ort5+ becomes #af & #cb miles1 respectively4 ,,! ,,causes ,,( ,,movem5t4 ,g5]al ,consid]ations4 ,! volume ( ! e>? is at all times dep5d5t on two sets ( antagoni/ic =ces1 7#a7 ! attractive or c5tripetal1 consi/+ ( gravity & ! molecul> & sub-molecul> attractions1 & 7#b7 ! resi/ant =ces--:i* are n necess>ily c5trifugal--consi/+ ( heat & ! resi/ant molecul> & sub-molecul> =ces4 #a4 ,! c5tripetal ag5cies4 ,gravity4--,! mo/ obvi\s ( ! conc5trat+ =ces is gravity1 & 9 mo/ que/ions relat+ to great segm5tal movem5ts1 x has be5 ?\ght suffici5t to consid] gravity alone1 b x is by no means c]ta9 t ?is does n lead to s]i\s error4 ,9 /udy+ ! causes & effects ( e>? movem5ts1 x is necess>y to consid] bo? gravitational en]gy & gravitational =ce4 ,gravitational en]gy is greate/ :5 ! mass is mo/ widely disp]s$1 & lea/ :5 mo/ conc5trat$4 ,gravitational =ce is greate/ :5 ! mass is mo/ conc5trat$1 & lea/ :5 mo/ disp]s$4 ,! gravitational en]gy ( ! e>? matt] 0 at its maximum :5 x 0 mo/ widely diffus$ 9 ! suppos$ nebul\s condition4 ,x w p]haps rea* its m9imum at "s future p]iod :5 ! %r9kage %all rea* its limit4 ,9 pass+ f an exp&$ condition to a m conc5trat$ condition1 pot5tial en]gy1 or en]gy ( position1 is trans=m$ into o!r =ms ( en]gy1 *iefly heat4 ,! heat ?us develop$ is an important factor 9 ! e>?'s dynamics4 ,! total am\nt ( gravitational en]gy involv$ 9 ! e>?'s evolution is unkn[n1 = nei!r ! maximum disp]sion ( ! e>lie/ /ate1 nor ! ultimate cond5sation1 is kn[n4 ,x is n difficult1 h[ev]1 to compute ! am\nt ( trans=mation ( gravitational en]gy into heat1 or o!r =ms ( en]gy1 dur+ a giv5 degree ( cond5sation4 ,if a mass equal to t ( ! e>? 7 orig9ally inf9itely scatt]$1 ! gravitational en]gy giv5 up by x 9 cond5s+ into a homog5e\s sph]e ( ! e>?'s pres5t size w\ld1 if all trans=m$ into heat1 suffice to raise ! temp]ature ( an equal mass ( wat] #hijj ,c4 7,hosk9s71 or an equal mass ( rock 7specific heat ( 4#b71 #dd1ejj ,c4 ,if ! mass 7 m cond5s$ t[>d ! c5t]1 z is ! actual case1 ! heat w\ld be consid]ably great]4 ,if ! cond5sation t[>d ! c5t] foll[$ ! ,laplacian law 7p4 #efd71 ! heat w\ld be suffici5t to raise ! e>? mass #dh1ijj ,c41 assum+ its specific heat to be 4#b1 :i* is ab\t ! av]age specific heat ( rock at ! surface 7,lunn74 ,a fur!r %r9kage ( "o mile w\ld trans=m an additional am\nt ( gravitational en]gy into heat ab\t equal 9 am\nt to ,tait's e/imate ( ! loss ( heat f ! surface ( ! e>? 9 #ajj1jjj1jjj ye>s 7see p4 #egb74 ,if ! radial %r9kage has be5 #cb miles1 or ev5 #af miles1 ! am\nt ( heat g5]at$ is v mu* great] ?an ! e/imat$ loss f ! surface4 ,h[ mu* gravitational en]gy c possibly be trans=m$ into heat & o!r =ms ( en]gy 9 ! future1 c only be comput$ by mak+ assumptions z to ! possible ext5t ( fur!r contraction1 & t involves hypo!ses z to ! atomic & sub-atomic con/itution ( ! e>?'s matt]1 & its behavior "u ! prodigi\s pressures ( ! e>?'s int]ior4 ,all %r9kage develops add$ gravitational =ce & fur!r t5d5cy to %r9kage1 :i* foll[s :5 ! heat g5]at$ by ! %r9kage is lo/2 & :]e ! process may end1 9 a body ( ! dim5sions ( ! e>?1 is beyond pres5t det]m9ation4 ,if !re 7 no limit to ! d5sity t might be atta9$1 x w\ld be impossible to assign any limit to ! en]gy t might be trans=m$4 ,x has usually be5 assum$ t contraction c\ld n g on indef9itely because ! atoms w\ld come into actual contact1 & prev5t fur!r increase ( d5sity4 ,?is conception re/s on ! rec5tly preval5t hypo!sis ( ! atomic con/itution ( matt]2 b ! m rec5t hypo!ses t sub/itute multitudes ( revolv+ corpuscles or electrons = irr$ucible atoms1 d n c>ry ! same presumption ( a rigor\s limit to cond5sation4 ,x is n !re=e prud5t to try to set su* a limit1 or to make x a feature 9 ! dynamical doctr9es ( ! e>?4 ,x is ev5 less prud5t to try to measure ! limit ( future conv]sion ( ! gravitational en]gy ( ! sun into heat1 & s to set a limit to ! habitability ( ! e>?4 ,! =ce ( gravity may be def9$ z ! ef=t ( gravitational en]gy to *ange into o!r =ms ( en]gy4 ,x is mo/ famili>ly express$ 9 t]ms ( weight1 :i* is ! resultant ( ! gravitational =ce ( ! :ole e>? ^u a giv5 portion4 ,weight is det]m9$ by ! di/ances & directions ( ! giv5 portion f all p>ts ( ! attract+ mass1 ! am\nt ( ! attraction be+ directly z ! mass & inv]sely z ! squ>e ( ! di/ance1 modifi$ by ! direction4 ,x is greate/ ab\t #faj miles bel[ ! surface1 :]e x is #a4jcib times t at ! surface4 ,bel[ ?is po9t x decl9es1 & at ! c5t] x is z]o4 ,! sum total ( ! e>?'s gravitative =ce at ! pres5t "t is equival5t to ab\t #f #aj tons4 ,?is gives rise to a pressure ( ab\t #c1jjj1jjj atmosph]es at ! c5t] ( ! e>?4 ,gravitational =ce is also express$ 9 t]ms ( ! e>?'s ability to accel]ate ! velocity ( fall+ bodies at its surface1 :i* is n[ approximately #cb feet p] second4 ,= c]ta9 purposes1 ! =ce ( gravity may be bett] pictur$ by means ( ! velocity requir$ to ov]balance x1 :i* is #f4i miles p] second2 e4g4 a body %ot away f ! surface at a spe$ exce$+ #f4i miles p] second1 w\ld escape f ! control ( ! e>? if ! influ5ce ( ! atmosph]e & o!r bodies is neglect$2 :ile a body %ot away at less ?an ?is spe$ w\ld return to ! e>?4 ,molecul> & sub-molecul> attractions4--,9 addition to gravity1 !re are at lea/ ?ree additional classes ( attractive ag5cies ^: laws appe> to diff] f ^? ( gravity1 viz4 cohesion1 *emical aff9ity1 & sub-atomic attraction1 us+ ^! t]ms 9 _! compreh5sive g5]ic s5ses4 ,! ?\ght has be5 ent]ta9$ t ^! might be r$ucible to =ms ( gravity 9 ult]ior analysis1 b x does n appe> f exi/+ evid5ce t ! laws ( _! attractions are con=mable to ! ,newtonian law ( ! inv]se squ>e ( ! di/ance1 to :i* gravity con=ms4 ,app>5tly ! =ces ( ! molecul>1 atomic1 & sub-atomic attractions increase at high] rates1 & h individual peculi>ities ( action q diff]5t f gravity4 ,x w\ld be ( ! utmo/ s]vice to geological philosophy if ^! laws ( molecul> & sub-molecul> attractions 7 firmly e/abli%$1 & c\ld be appli$ to ! conditions ( heat & pressure "u :i* ! matt] ( ! int]ior ( ! e>? exi/s4 ,9 ! abs5ce ( su* det]m9ations1 we c d little m ?an recognize t ! matt] ( ! int]ior ( ! e>? t5ds to cond5se itself by ! aid ( molecul> & sub-molecul> attractions1 supplem5tal to ! attraction ( gravity4 ,cohesion & cry/allization4--,! =ce ( gravity betwe5 small bodies is exce$+ly feeble1 b x is cumulative1 e p>ticle 9 a mass attract+ e o!r p>ticle1 s t 9 great masses ! =ce becomes enorm\s4 ,9 cohesion1 & probably 9 ! o!r molecul> & sub-molecul> attractions1 ! p>ticles attract v /rongly ! p>ticles ) :i* !y are 9 close relations1 b beyond m9ute di/ances _! effects are ins5sible4 ,! =ce ( cry/allization is felt = a v %ort di/ance f ! cry/al1 & 8mass action0 is probably dep5d5t on a function ( simil> k9d1 act+ at a v small di/ance1 b ! range ( ^! =ces is v limit$ 9 comp>ison ) t ( gravity4 ,rock matt]1 z a rule1 t5ds to become cry/all9e by ! assembl+ ( l molecules 9 sy/ematic ord]4 ,! g5]al effect is cond5sation1 ?\gh ?is is n univ]sally ! case1 = 9 "s in/ances ! cry/all9e arrangem5t results 9 expansion4 ,! cry/alliz+ =ce may be reg>d$ z a specializ$ v>iety ( cohesion :i* usually cop]ates ) gravity to produce increas$ d5sity4 ,9 cases ( expansion x seems cle> t ! organiz+ =ce does n act accord+ to ! law ( gravity4 ,! int5sity ( ! =ce exhibit$ 9 ! =mation ( ice illu/rates ! sup]iority ( ! molecul> =ce ov] ! gravitative =ce 9 small masses2 b 9 a planet ( ice ( v mod]ate dim5sions1 ! int]nal pressure ( gravity w\ld ov]come ! cry/all9e =ce1 :i* illu/rates ! sup]iority ( gravity 9 l>ge masses4 ,:ile ! cry/all9e =ce may ?us 9 exceptional cases op]ate aga9/ gravity1 x is kn[n t 9 mo/ cases x n only op]ates ) x1 b is controll$ by x1 9 ?is s5se--t :]e a sub/ance has two =ms ( cry/allization1 x w take ! d5s] "o :5 ! pressure is great4 ,! inf]5ce is t if ! less d5se =m ( cry/allization takes place "u slight pressure1 & subsequ5tly ! pressure is greatly increas$1 ! =m ( cry/allization w *ange f ! less to ! m d5se4#bdg ,x is probable t 9 g5]al ^? =ms ( molecul> arrangem5t w be assum$ 9 ! deep zones :i* give ! greate/ d5sity1 & ?is probably includes concretion>y1 colloidal1 & o!r =ms ( aggregation1 z well z cry/allization4 ,diffusion4--,! same law probably holds relative to diffusion1 ?\gh 9 a molecul> s5se diffusion is ! opposite ( cry/allization1 = 9 cry/allization1 l comes to l1 :ile 9 diffusion ! molecules di/ribute !mselves among ^? ( unlike nature4 ,diffusive action1 q famili> 9 gases & liquids1 takes place to "s ext5t 9 solids4 ,! molecules ( plates ( gold & lead br\ght into intimate contact "u pressure mutually diffuse among "o ano!r4 ,s gases seem to be v g5]ally diffus$ or 8occlud$0 9 rocks1 ?\gh ! nature ( ?is relation is imp]fectly det]m9$4 ,x is kn[n t pressure ^u gases promotes _! diffusion ?r\gh liquids & solids4 ,x is inf]r$ t pressure ^u a solid t5ds to ! diffusion ( ! entrapp$ gases )9 x1 b x is n to be inf]r$ f ?is t pressure ^u rock promotes ! absorption ( gases into x1 b r ! opposite4 ,x is probable t great pressure ) high heat promotes ! diffusion ( entrapp$ gases or o!r diffusible sub/ances ?r\gh ! rock-mass1 & at ! same "t t5ds to _! extrusion along l9es ( lea/ resi/ance2 b ?is is an inf]5ce r ?an a demon/ration4 ,*emical comb9ation4--,! g5]al effect ( *emical comb9ation "u pressure is great] d5sity4 ,9 rev]sible reactions capable ( conditions ( *emical or physical equilibrium1 pressure inv>iably favors ! =mation ( ! d5s] ( any possible products4 ,sub-atomic =ces4--,rec5t inve/igation has made x probable t atoms are composite1 embrac+ _m exce$+ly m9ute bodies--corpuscles or electrons--9 a /ate ( extremely high activity & possess$ ( m>vel\s en]gy not)/&+ _! m9ut5ess4 ,?is discov]y possesses deep int]e/ to ! geologi/ because x seems to reveal s\rces ( en]gy ( almo/ incalculable pot5cy1 "s portions ( :i* at lea/ are be+ con/antly fre$ & add$ to ! previ\sly recogniz$ supplies ( en]gy4 ,attempts h be5 made dur+ ! pa/ few decades to limit ! habitable age ( ! e>?1 bo? retrospectively & prospectively1 by ! smallness ( ! sum total ( en]gy d]ivable f gravity4 ,9 ^! e/imates slight recognition has be5 giv5 to ! res\rces ( molecul> & atomic en]gy1 & none at all to ! possibilities ( sub-atomic en]gy4 ,x w\ld be go+ q too f> to assume t ^! sub-atomic en]gies are all available = ! p]petuation ( habitable conditions on ! e>? or 9 ! sol> sy/em1 b we are d\btless ju/ifi$ 9 appeal+ to !m z an (fset to all dicta re/rict+ ! p]iod ( ! e>?'s habitability by suppos$ insuffici5cies ( en]gy d$uc$ m]ely f ! e/imat$ res\rces ( gravity4 ,! bani%m5t ( ! idea ( ! atom z a m9ute1 incompressible1 undecomposable sph]e takes away ! !oretical limit ( compressibility1 & by s do+ cuts away ! gr\ndwork = assign+ def9ite limits ev5 to ! res\rces ( gravity1 s9ce1 z already indicat$1 unlimit$ cond5sation gives !oretically unlimit$ trans=mation ( ! pot5tial en]gy ( gravity4 ,:ile we mu/ await ) su* pati5ce z we c comm& ! developm5t ( full] k conc]n+ ! nature & laws ( ! molecul>1 atomic1 & sub-atomic en]gies1 & _! applicability to ! activities resid5t 9 ! int]ior ( ! e>?1 x is p]missible ev5 n[ to assume t1 besides ! simple compressive action ( gravity1 !re are at "w v>i$ =ms ( molecul> aggregation1 ( atomic comb9ation1 & p]haps ( sub-atomic *ange1 t5d+ t[>d increas$ d5sity1 & t ! ult]ior limit ( ^! processes is q undet]m9$4 ,! cond5sational =ces are n[ re/ra9$ at c]ta9 tempor>y limits by ! antagoni/ic resi/ant =ces1 "s ( :i*1 su* z heat1 are ! products ( ! cond5sational =ces1 & are gradually be+ dissipat$1 p]mitt+ fur!r cond5sation4 ,:]e ! process may ultimately end1 we d>e n attempt to say4 ,on ! o!r h&1 we are n compell$ to accept assign$ limits t seem to be inconsi/5t ) ! ph5om5a :i* ! e>? actually pres5ts4 #b4 ,! resi/+ ag5cies4 ,heat4--,! mo/ famili> ( ! active ag5cies t resi/ cond5sation is heat4 ,^u ?is ! exi/+ volume ( ! e>? is imm$iately dep5d5t1 9 "s l>ge "p at lea/4 ,z ?is heat is dissipat$1 ! e>? %r9ks4 ,?is %r9kage increases ! =ce ( gravity1 & h5ce ! int]nal pressure increases1 &1 if fur!r compression takes place z ! result ( ?is increas$ pressure1 additional heat is develop$1 :i* *ecks fur!r cond5sation until x is dissipat$4 ,x is ?is k9d ( creative & self-*eck+ action t det]m9es ! volume ( great gase\s bodies l ! sun4 ,?\gh _! matt] is f> f its ultimate d5sity1 & _! self-gravity is enorm\s1 !y cond5se sl[ly1 because1 ) e /age ( cond5sation1 heat is g5]at$ :i* antagonizes gravity & *ecks cond5sation1 until at lea/ a "p ( ! heat is radiat$ away4 ,z ! =ce ( gravity increases ) e /age ( cond5sation1 ! heat develop$ to hold x 9 *eck mu/ increase1 & h5ce ! fam\s law ( ,lane1 t a gase\s body l ! sun gr[s hott] z x cond5ses4 ,?is law holds good :ile ! body rema9s 9 a gase\s /ate 9 :i* ! ma9t5ance ( ! volume is ess5tially dep5d5t on heat4 ,:5 a body becomes liquid or solid1 its volume is dep5d5t 9 "p on =ms ( resi/ance o!r ?an heat1 & ! =ce ( ! law is abat$1 ?\gh ! pr9ciple /ill holds good4 ,9 small solids1 ! pr9ciple has little application1 s9ce ! =ce ( self-gravity is slight comp>$ to ! resi/+ =ces1 & v little new heat is g5]at$ z ! body loses t :i* x has2 b 9 l>ge bodies1 l ! e>?1 :]e ! cond5sational =ces are enorm\s & ! int]nal temp]ature is v high1 x is n improbable t ! heat g5]at$ at e /age ( cond5sation is relatively l>ge4 ,x has be5 inf]r$ by "s /ud5ts ( ! ph5om5a t ! conditions 9 ! int]ior ( ! e>? are ess5tially ^? ( gase\s matt]1 s f> z molecul> relations are conc]n$1 because ! temp]atures are ?\ght to be above ! critical temp]atures ( ! sub/ances compos+ x4 ,if ?is be true1 ! new heat g5]at$ ) ea* /age ( cond5sation is l>ge4 ,h[ev] ?is may be1 x seems safe to inf] t 9 s f> z ! volume ( ! int]ior mass is dep5d5t on heat resi/ance1 ! loss ( exi/+ heat leads to ! g5]ation ( new heat4 ,! am\nt ( ?is new heat mu/ be en\gh1 toge!r ) ! residual heat & ! o!r =ces ( resi/ance1 to mat* ! new cond5sational =ces4 ,! molecul> & sub-molecul> =ces ( resi/ance o!r ?an heat1 are probably responsible = "s l>ge "p ( ! resi/ance to ! increas$ cond5sational =ce1 b h[ mu* is n det]m9$4 ,all resi/ance p]haps due to motion4--,z n[ int]pret$1 ! =ce ( resi/ance ( heat is due to ! impact ( ! fly+ p>ticles ( ! heat$ matt]4 ,! o!r =ms ( resi/ance to compression h n usually be5 int]pret$ 9 ?is way1 b ! t5d5cy ( rec5t inve/igation is to place !m 9 ! same dynamic class4 ,a cold solid body (f]s resi/ance to compression t is 9 no obvi\s way dep5d5t on heat motion4 ,9 small bodies ?is resi/ance is immeasurably great] ?an ! self-gravity ( ! body4 ,x is s great t x c only be p>tially ov]come by any =ce :i* human +5uity c br+ to be> ^u x4 ,?is =m ( resi/ance has ?us1 n unnaturally1 come to be reg>d$ z approximately immeasurable1 & p]haps z grad+ into actual immeasurability1 & z re/+ back ^u ! actual contact ( irr$ucible atoms4 ,b ! rec5t rese>*es :i* h develop$ gr\nds = ! conception t ev5 ! atoms are composite1 lead to ! fur!r conception t _! resi/ance to compression is dep5d5t on ! movem5t ( _! con/itu5t corpuscles or electrons4 ,?is enc\rages ! broad conception t ! :ole ( ! resi/ance to compression arises f molecul>1 atomic1 & sub-atomic motions1 ( :i* heat is m]ely "o =m4 ,:ile all ?is is yet on ! fronti] ( physical progress1 ^! conceptions may well be recogniz$ 9 fram+ int]pretations ( ! ag5cies :i* det]m9e ! volume ( ! e>?1 & :i* control ! *anges t take place 9 x f age to age4 ,! result ( _! comb9$ action at any /age is a /ate ( tempor>y equilibrium betwe5 gravity1 aid$ by ! molecul>1 atomic1 & sub-atomic attractions1 on ! "o h&1 & heat1 aid$ by ! molecul>1 atomic1 & sub-atomic resi/ances1 on ! o!r4 ,! vital problem is to asc]ta9 ! orig9al condition ( balance betwe5 ^! antagoni/ic =ces1 & ! *anges :i* h affect$ t balance s9ce4 ,! orig9al /ate ( balance is necess>ily a matt] ( hypo!sis1 & ! be/ t c be done at pres5t is to picture z cle>ly z possible ! diff]5t hypo!ses t h be5 ent]ta9$1 & ! diff]5t consequ5ces t logically fl[ f !m4 ,! mo/ important factor 9 ! case is ! orig9al am\nt & di/ribution ( int]nal heat4 ,,alt]native ,,views ,,( ,,orig9al ,,heat ,,di/ribution4 ,! hypo!tical modes ( orig9 ( ! e>? w be treat$ 9 ! hi/orical section4 ,suffice x "h to say t "o view is t ! e>? 0 once gase\s1 pass$ !nce into a liquid1 & lat] into a solid /ate4 ,"u ?is view1 !re are two hypo!ses z to ! orig9al di/ribution ( int]nal heat1 dep5d5t on ! mode ( solidification4 ,accord+ to ! "o1 solidification began at ! surface aft] convection _h br\ght ! temp]ature ( ! :ole mass d[n ne>ly to ! po9t ( congelation2 accord+ to ! o!r1 solidification began at ! c5t] at a high temp]ature1 because ( pressure1 & proce$$ !nce outw>ds4 ,! =m] only has be5 mu* develop$ 9 ! lit]ature ( ! subject1 ?\gh ! latt] is n[ g5]ally reg>d$ z ! m probable4 ,ano!r view ( ! globe's orig9 is t ! e>? 0 built up gradually by ! infall ( matt]1 bit by bit1 at su* a rate t ?\gh ea* little mass became hot z a result ( its fall1 x cool$ (f be=e o!rs fell on ! same spot1 ! ra9 ( matt] n be+ fa/ en\gh to heat up ! :ole mass to ! melt+-po9t4 ,"u ?is view1 ! int]nal heat arose *iefly f compression due to ! e>?'s gravity4 ,a cle> conception ( ! ?ree hypo!ses ( !rmal di/ribution :i* re/ on ^! two views ( ! orig9 ( ! e>? is important to ! fur!r discussion4 #a4 ,!rmal di/ribution on ! convection hypo!sis4--,x 0 =m]ly ! prevail+ op9ion t ! molt5 condition ( ! e>? p]si/$ 9 ! int]ior until aft] ! cru/ _h =m$1 & t solidification proce$$ f ! surface d[nw>ds4 ,x 0 a natural coroll>y ( ?is view t1 previ\s to ! beg9n+ ( solidification1 convection /irr$ ! liquid mass f c5t] to circumf]5ce & equaliz$ ! temp]ature s t ! :ole mass cool$ d[n equably until x approa*$ ! po9t ( solidification & became too visc\s = ready convection4 ,! temp]ature %\ld1 !re=e1 h be5 ne>ly ! same f c5t] to surface at ! /age j prec$+ incipi5t solidification4 ,?is conception =ms ! basis ( mo/ discussions involv+ int]nal temp]atures4#bdh ,! fam\s /udies ( ,"l ,kelv9 are bas$ on ! assumption ( a uni=m initial temp]ature ( #gjjj ,fahr4#bdi ,o!r temp]atures h be5 assum$ 9 simil> /udies by o!rs1 b ! results d n diff] mat]ially4 ,on ?is hypo!sis !re w\ld be no deep-seat$ *ange ( temp]ature until a temp]ature-gradi5t1 ext5d+ to ! deep] horizons1 _h be5 develop$ by surface cool+4 ,9 ! e>lie/ eras1 ! loss ( heat w\ld be felt solely 9 ! out] zone4 ,by surface cool+1 a temp]ature gradi5t w\ld be sl[ly develop$1 & gradually *ang$ f age to age1 z %[n by ! curv$ l9es 9 ,fig4 #dej1 ea* ( :i* %[s ! temp]ature at ! successive /ages /at$ 9 ! leg5d4 ,! computations = ^! curves 7 bas$ on ! me?ods & assumptions ( ,"l ,kelv94 ,! two l[] curves repres5t great] p]iods ?an ^? usually assign$ by geologi/s to ! :ole hi/ory ( ! e>?4 ,x w be se5 t ! modification ( ! orig9al temp]ature l9e ext5ds only ab\t #afj miles bel[ ! surface = ! #ajj1jjj1jjj-ye> p]iod1 only ab\t #bdj miles = ! #bcg1jjj1jjj-ye> p]iod1 & only ab\t #cbj miles = ! excessive p]iod ( #fjj1jjj1jjj ye>s4 ,! sup]ficial nature ( ! :ole !rmal problem "u ?is hypo!sis is ?us made cle> & impressive4 ,illu/ration3 ,fig4 #dej4--;,diagram %[+ ! orig9al di/ribution ( heat assum$ by ! convection hypo!sis & ! modifications ( ?is di/ribution ne> ! surface 9 successive long p]iods4 ,! base-l9e ( ! figure repres5ts divisions ( ! e>?-radius ) c5t] at ! left & surface at ! "r4 ,! v]tical l9es repres5t temp]atures rang+ f #j ,c4 to #ejjj ,c4 ,! assum$ initial temp]ature #cijj ,c4 7#gjjj ,f47 is repres5t$ by ! horizontal l9e ,,tc1 full at ! left & dott$ at ! "r to indicate ! orig9al ext5sion ( ! initial temp]ature to ! surface4 ,! upp] curve at ! "r %[s h[ mu* ! temp]ature w h be5 modifi$ at ! end ( #ajj1jjj1jjj ye>s1 comput$ accord+ to ! me?od ( ,"l ,kelv94 ,! middle curve %[s ! *ange at ! end ( #bcg1jjj1jjj ye>s1 & ! l[] curve ! *ange at ! end ( #fjj1jjj1jjj ye>s4 ,simil> curves may be f\nd 9 an article by ,cl>5ce ,k+1 ,am4 ,j\r4 ( ,sci41 ,,xlv1 #ahic1 p4 #af4 ,aft] ! out] %ell _h cool$ s z to be 9 approximate equilibrium ) ! environm5t ( ! e>?1 x suff]$ practically no contraction4 ,s also x appe>s f ! diagram t !re 0 practically no contraction bel[ #afj miles up to ! end ( ! #ajj1jjj1jjj-ye> p]iod1 because cool+ _h n yet rea*$ t dep?4 ,betwe5 ^! two non-contract+ horizons ! greate/ rate ( contraction at ! close ( ! #ajj1jjj1jjj-ye> p]iod lay ab\t #fj miles bel[ ! surface4 ,! contraction ( ?is middle zone1 :ile ! out]mo/ %ell & ! int]ior body rema9$ con/ant1 is held to h develop$ a /ate ( horizontal ?ru/ 9 ! out] %ell1 because ?is %ell1 be+ too l>ge = ! %r9k+ subcru/1 t5d$ to settle1 & to cr[d ^u itself horizontally4 ,! wr9kl+ & o!r modes ( de=mation ( ! out] "p ( ! e>? are ref]r$1 "u ?is view1 to ! ?ru/ s develop$4 ,?is is ! view :i* has be5 mo/ g5]ally accept$4 ,level ( no /ress4--,z ! out] %ell is ?us held to be 9 a /ate ( ?ru/ :ile ! zone bel[ is 9 a /ate ( %r9kage1 !re mu/ be1 betwe5 ^! two zones1 a level ( no /ress1 :]e !re is nei!r compression nor /ret*+4 ,above ?is level1 ! ?ru/ increases to ! surface1 & bel[ x1 ! /ret*+ increases to ! dep? ( mo/ rapid *ange ( temp]ature1 bel[ :i* x decreases & f9ally vani%es at ! l[] limit ( temp]ature *ange4 ,9 ! e>lie/ /ages ( cool+1 ! level ( no /ress mu/ h be5 ne> ! surface1 & mu/ h desc5d$ gradually z ! cool+ proce$$4 ,! dep? ( ?is level has be5 repeat$ly comput$ on ! basis ( assum$ times & rates ( cool+4 ,fi%]1 assum+ ! temp]ature ( solidification to h be5 #djjj ,fahr4 & ! p]iod ( cool+ #cc1jjj1jjj ye>s1 comput$ its dep? at only ( a mile bel[ ! surface4#bej ,t4 ,mell>d ,reade1 ) some:at diff]5t assumptions1 plac$ x at #b miles aft] #ajj1jjj1jjj ye>s ( cool+4#bea ,davison 7#ahig7 plac$ x at #b4ag miles1#beb & ,g4 ,h4 ,d>w9 at #b miles aft] ! same p]iod4#beb ,9 a lat] computation1 bas$ on ! assumption t ! coeffici5t ( dilatation increases ) ! temp]ature1 ,davison plac$ ! level ( no /ress at #g4gi miles1 & /at$ t if ! coeffici5t ( conductivity & ! initial heat also increas$ d[n w>ds1 ! zone w\ld lie /ill deep]4 ,to suppose ! initial heat to increase d[nw>ds1 h[ev]1 is to ab&on ! hypo!sis we are n[ consid]+4 ,^! computations seem to %[ t1 at ! v utmo/1 ! level ( no /ress1 "u ?is hypo!sis1 lies at a v slight dep?1 & t ! ?ru/ zone above is1 !re=e1 v %all[4 ,?is %\ld be kept con/antly 9 m9d 9 all d$uctions drawn f ?is hypo!sis4 ,if ! ?ickness ( ! ?ru/ zone be tak5 at #h or #aj miles1 x w app>5tly be conc$+ to ! view all t c legitimately be claim$ = x4 ,illu/ration3 ,fig4 #dea4--;,diagram illu/rat+ ! int]nal temp]atures ( ! e>? :5 x fir/ became solid1 "u ! hypo!sis t x solidifi$ f ! c5t] outw>d1 & assum+ t ! fus+-po9t rose directly z ! pressure1 9 accordance ) ,b>us' exp]im5ts ) diabase4 ,! divisions ( ! base-l9e repres5t fractions ( ! e>?'s radius4 ,! divisions ( ! v]tical l9es repres5t pressures 9 atmosph]es at ! left1 & temp]atures 9 degrees ,c4 at ! "r4 ,! l[] curve1 ,,pc1 repres5ts ! int]ior pressures1 rang+ f "o atmosph]e at ! surface to #c1jjj1jjj atmosph]es at ! c5t]1 d]iv$ f ,laplace's law ( d5sity4 ,! upp] curve1 ,,fc1 repres5ts ! fusion-po9ts ( diabase at ! v>i\s dep?s & pressures1 & h5ce ! temp]atures at :i* ! int]ior w\ld become solid at ! v>i\s dep?s1 or1 9 o!r words1 ! initial temp]atures ( ! solid e>?4 ,! l[] curve is d]iv$ f ,sli*t]2 ! upp] is =m$ by directly plott+ ! temp]atures giv5 by ,b>us 7,am4 ,j\r4 ,sci41 #ahic1 p4 #g74 #b4 ,!rmal di/ribution on ! hypo!sis ( c5tral solidification4--,:5 ! previ\s conception 0 fir/ =m$1 ! effect ( pressure on ! melt+-po9ts ( lavas 0 neglect$1 z little or no?+ 0 kn[n on ! subject4 ,exp]im5t1 h[ev]1 has %[n t pressure1 z a rule1 raises ! melt+-po9ts ( lavas1 & out ( ?is has gr[n ! doctr9e t ! e>? solidifi$ fir/ at ! c5t]1 :]e ! pressure 0 greate/1 & gradually congeal$ outw>ds4 ,b>us has %[n t ! melt+-po9t ( diabase1#bec select$ z a repres5tative rock1 rises directly ) ! pressure4 ,if ?is rate holds good to ! c5t] ( ! e>?1 ! melt+ temp]ature ( diabase !re w\ld be #gf1jjj ,c4 7#acf1hjj;,f474 ,! range ( ! exp]im5t is1 h[ev]1 v small comp>$ ) ! range ( ! application1 & little confid5ce c be felt 9 ! special num]ical result rea*$4 ,! rate ( rise ( ! fusion-po9t may be mu* *ang$ z ! extraord9>y conditions ( ! deep int]ior are invad$4 ,/ill !re is good gr\nd = ! hypo!sis t solidification took place at "s v high temp]ature at ! c5t]1 because ( ! v great pressure !re4 ,! inf]5ce !n is t :5 ! temp]ature ( ! c5t] ( ! suppos$ molt5 globe rea*$ ! appropriate po9t1 solidification began !re1 & t x took place at less] dep?s 9 succession z ! appropriate temp]atures 7 rea*$4 ,?is view excludes convection 9 ! successive zones f ! c5t] outw>d aft] ! "t :5 _! temp]atures ( solidification 7 rea*$1 or aft] ^! 7 approa*$ suffici5tly ne> to develop prohibitive viscosity4 ,"s loss ( heat f ^! horizons w\ld be suff]$ :ile ! out] p>ts 7 solidify+1 b on acc\nt ( ! exce$+ly sl[ conductivity ( rock1 x is improbable t ! am\nt ( loss w\ld be suffici5t to *ange ! g5]al "* ( ! int]nal di/ribution ( heat previ\s to solidification at ! surface1 ! "t :5 ! exi/+ phase ( ! e>?'s hi/ory by hypo!sis began4 ,fig4 #dea %[s ! !oretical di/ribution ( heat "u ?is view4 ,! consequ5ces ( ?is assumption are v important to geological !ory &1 c>ri$ out to _! logical consequ5ces1 lead to ! conclusion t cool+ & %r9kage affect$ ! deep int]ior ( ! e>?1 = ! high c5tral heat mu/ h be5 con/antly pass+ out t[>d ! surface4 ,in/ead1 !re=e1 ( ! contraction be+ conc5trat$ 9 & limit$ to ! out] #bjj miles or s1 z "u ! prec$+ hypo!sis1 x 0 deeply di/ribut$4 ,! contraction )9 ! out] zone w\ld be less ?an "u ! prec$+ view1 because ! fl[ ( heat f )9 w\ld p>tially (fset ! fl[ outw>ds1 & a correspond+ "p ( ! contraction w\ld be di/ribut$ bel[4 ,,comput$ ,,pressures1 ,,d5sities1 ,,& ,,temp]atures ,,)9 ,,! ,,e>? ,,bas$ ,,on ,,laplace's ,,law4 ---------------------------------------- --------- ,di/ance ,pressure f c5t] 9 megadynes ,temp]ature 9 t]ms ( p] sq4 ,d5sity4 9 radius4 cm4#bed degrees ,c4 ---------------------------------------- --------- #a4jj #j #b4hj #j 4#ie #ig1jjj #c4cg #cbj 4#ij #bae1jjj #c4ie #a1aaj 4#he #cec1jjj #d4ed #b1aij 4#hj #eaj1jjj #e4ac #c1dgj 4#ge #fhd1jjj #e4ga #d1hhj 4#gj #hgd1jjj #f4bh #f1cej 4#fe #a1jgg1jjj #f4hd #g1hfj 4#fj #a1bhi1jjj #g4ch #i1cfj 4#ee #a1ejg1jjj #g4ij #aj1hcj 4#ej #a1gbg1jjj #h4ci #ab1bej 4#de #a1idd1jjj #h4hd #ac1eij 4#dj #b1aed1jjj #i4bf #ad1hdj 4#ce #b1cec1jjj #i4fd #ae1ihj 4#cj #b1ece1jjj #i4ih #ag1jjj 4#be #b1fih1jjj #aj4bg #ag1hhj 4#bj #b1hcf1jjj #aj4ea #ah1faj 4#ae #b1idg1jjj #aj4gj #ai1aij 4#aj #c1jbi1jjj #aj4hd #ai1faj 4#je #c1jgh1jjj #aj4ib #ai1hgj 4#jj #c1jie1jjj #aj4ie #ai1iej ---------------------------------------- --------- #c4 ,!rmal di/ribution "u ! accretion hypo!sis4--,! accretion hypo!sis assumes t ! int]nal heat 0 gradually develop$ f ! c5t] outw>ds z ! e>? grew & ! int]nal compression 0 progressively develop$4 ,! heat1 !re=e1 cont9u$ to rise at ! c5t] z long z compression cont9u$1 or at lea/ z long z ! compression 0 suffici5t to g5]ate heat fa/] ?an x 0 conduct$ outw>ds4 ,z ! conduction ( heat ?r\gh rock is exce$+ly sl[1 ! c5tral heat may be assum$ to h cont9u$ to rise s long z ! infall ( matt] caus$ appreciable compression4 ,9 ! same way1 heat 0 g5]at$ progressively 9 ! less c5tral p>ts1 & ^! p>ts also receiv$ ! heat t pass$ out f b5ea?4 ,x is assum$ "u ?is hypo!sis t ! degree ( int]ior compression /&s 9 close relation to int]ior d5sity1 = :ile !re w\ld probably be "s segregation ( heavi] matt] t[>d ! c5t] & ( light] t[>d ! surface by means ( volcanic action & int]nal re>rangem5t "u /ress diff]5ces1 ! int]ior d5sity is reg>d$ z due ma9ly to compression4 ,! di/ribution ( int]nal pressure & d5sity g5]ally accept$ is t ( ,laplace1 :o assum$ t ! increase ( ! d5sity v>ies z ! squ>e root ( ! increase ( ! pressure4 ,?is law gives a di/ribution ( d5sity t accords fairly well ) ! ph5om5a ( precession ( ! equ9oxes1 :i* require t ! high] d5sities ( ! int]ior %all be di/ribut$ 9 c]ta9 proportions betwe5 ! c5t] & ! equatorial protub]ance ^: attraction by ! sun & moon causes precession4 ,! increases 9 pressure1 d5sity1 & temp]ature h be5 comput$ z foll[s by ,mr4 ,a4 ,c4 ,lunn1#bee ! av]age specific gravity ( ! e>? be+ tak5 at #e4f1 ! surface specific gravity at #b4h1 & ! specific heat at 4#b4 ,! temp]atures are %[n graphically 9 ,fig4 #deb1 9 :i* ! curves ( pressure & d5sity are also giv54 ,! nature ( ! curve ( temp]ature is su* t1 if ! !rmometric conductivity ( ! mat]ial is uni=m at all dep?s1 ! temp]ature w fall 9 ! deep] portions & rise 9 ! out] ones1 exclud+ ! surface portions subject to outside cool+4 ,! curve indicates t ! ris+ temp]ature w\ld affect some:at m ?an #hjj miles ( ! out] "p ( ! sph]oid1 or ab\t half its volume1 i4e4 ! inn] half dur+ ! initial p]iod _h a fall+ temp]ature & ! out] half1 except ! imm$iate surface1 a ris+ temp]ature4 ,?is introduces a v s+ul> feature into ! problem1 = ! out] zone mu/ %r9k to fit ! inn] portion t is los+ heat1 :ile its own mat]ial is exp&+ because ( its increase ( temp]ature4 ,a d\ble di/ortional effect mu/ result4#bef ,if ! conductivity ( ! d5se int]ior is great] ?an t ( ! out] p>ts1 ! effect is int5sifi$4 ,! r$i/ribution ( heat result+ f ?is unequal fl[age w\ld 9 "t *ange ! curve s t m ne>ly equal fl[age w\ld result4 ,x w\ld probably take a v long p]iod = ?is to be effect$1 on acc\nt ( ! v sl[ conductivity ( rock4 ,! accretion hypo!sis assumes t1 dur+ ! gr[? ( ! e>?1 l>ge am\nts ( heat 7 c>ri$ by volcanic action f deep] horizons to high] ones & to ! surface1 & t ?is /ill cont9ues at a dim9i%$ rate4 ,x assumes t :5ev] ! int]ior heat rais$ any con/itu5t ( ! int]ior matt] above its fus+-po9t "u ! local pressure1 x pass$ into ! liquid /ate1 & 0 =c$ outw>ds by ! /ress diff]5ces to :i* x 0 subject$1 unless its specific gravity 0 suffici5tly high to c\nt]balance !m4 ,x is conceiv$ t ! m fusible portions 7 liquefi$ fir/1 & t 9 s do+ !y absorb$ ! necess>y heat ( liquefaction & began to "w _! way outw>d1 c>ry+ _! heat into high] horizons & tempor>ily *eck+ ! developm5t ( m int5se /resses 9 ! l[] horizons4 ,!y ?us s]v$ to keep ! temp]ature !re bel[ ! fusion-po9t ( ! rema9+ m refractory sub/ances4 ,mean:ile ! extrud$ portions 7 rais+ ! temp]atures ( ! high] horizons into :i* !y 7 intrud$ or ?r\gh :i* !y 7 =c$ to pass4 ,!re 0 ?us1 x is ?\ght1 an automatic action t t5d$ to r$uce ! heat-curve to ! fusion-curve4 ,! actual curve ( int]nal temp]ature may1 !re=e1 be practically ! fusion-curve4 ,?is is id5tical ) ! curve suppos$ to arise f solidification by pressure f ! c5t] outw>d "u ! molt5 hypo!sis1 except s f> z ! two w\ld v>y z ! result ( v>iations 9 ! di/ribution ( matt]1 :i* w\ld n be q ! same "u ! two hypo!ses4 ,! curve ( fusion d$uc$ by an ext5sion ( ! results ( ,b>us' exp]im5t has be5 giv54 ,x is necess>y to recognize t ! rate ( rise ( ! fusion-po9t may1 & v likely does1 *ange 9 ! deep int]ior4 ,! curve giv5 repres5ts mu* high] temp]atures 9 ! c5tral p>ts ?an ^? giv5 by ,lunn's computations f compression1 :i* seem inh]5tly m probable ?an ! high] ones4 ,illu/ration3 ,fig4 #deb4--;,diagram illu/rat+ ! di/ribution ( temp]ature "u ! accretion hypo!sis 7neglect+ ! heat f infall & o!r ext]nal s\rces74 ,! divisions ( ! base-l9e repres5t fractions ( ! e>?'s radius4 ,! v]tical divisions repres5t bo? pressure 9 megadynes p] sq4 cm41 ne>ly ! same z atmosph]es p] sq4 941 at ! left1 & temp]atures 9 degrees ,c4 at ! "r4 ,x is to be not$ t ! temp]ature scale is #bjjj ,c4 p] division1 :ile t ( ,fig4 #dea is #ejjj ,c4 p] division4 ,! upp] curve at ! left1 ,,pc1 is ! pressure curve4 ,! middle curve1 ,,dc1 is ! d5sity curve1 beg9n+ at #b4h at ! surface & rea*+ ne>ly #aa at ! c5t]4 ,! l[] curve1 ,,tc1 is ! temp]ature curve1 ris+ f ! surface temp]ature1 #j ,c41 at ! "r1 to #bj1jjj ,c4 at ! c5t]4 ,x is to be not$ t ! portion ( ?is curve at ! left repres5t+ ! deep] "p ( ! e>? is convex upw>ds1 :ile ! portion at ! "r is concave4 ,x w be se5 t ! gradi5t increases f ! c5t] to a po9t betwe5 4#f & 4#g radius1 & !n decreases1 & t betwe5 4#h radius & ! surface1 a di/ance ( ab\t #hjj miles1 ! decrease is notable4 ,?is means t ) an equal coeffici5t ( conductivity ! fl[ f ! c5t] outw>d to 4#f or 4#g radius w be fa/] ?an ! fl[ f 4#h radius to ! surface1 neglect+ ! imm$iate surface effects ( ext]nal cool+4 ,^! curves 7 work$ out by ,mr4 ,lunn4 ,z a/ronomical & seismic evid5ces /rongly favor ! view t ! e>? is rigid ?r\gh\t1 !y l5d support to ! view t ! int]ior reta9s its rigidity by ! extrusion ( liquid matt] practically z fa/ z x is =m$1 & t ?is progressive extrusion adju/s ! temp]ature to t :i* is consi/5t ) solidity4 ,! be>+ ( ?is conception becomes evid5t on consid]ation4 ,! %r9kage ( ! e>? f loss ( heat by conduction & by ! extrusion ( molt5 rock1 affects ! deep int]ior z well z ! m sup]ficial zones4 ,x is ev5 possible t ! %r9kage may orig9ate *iefly 9 ! deep] zones4 ,! po/ulat$ transf] ( fluid rock f ! deep] p>ts to ! m sup]ficial ones less5s ! heat 9 ! =m]1 & adds to t 9 ! latt]4 ,! po/ulat$ great] fl[ ( heat f ! deep] half to ! out] half1 ?an f ! latt] outw>d1 gives a concordant result4 ,if ! conductivity ( ! deep] & d5s] mat]ial is appreciably great] ?an t ( ! m sup]ficial & less d5se mat]ial1 z seems probable1 ?is effect is int5sifi$4 ,! di/ribution ( compressibility at ! exi/+ /ate ( cond5sation may possibly be su* t m new heat is g5]at$ by %r9kage 9 ! out] p>ts ?an 9 ! inn]4 ,nei!r ( ^! conceptions c be affirm$ z actually tak+ place4 ,!y m]ely lie )9 ! range ( reasonable hypo!sis 9 ! pres5t /ate ( exp]im5tal data4 ,:at ! real tru? is mu/ be left to fur!r rese>*4 ,pres5t ef=t may be reg>d$ z tempor>ily successful if x =ms consi/5t conceptions ( ! applicable hypo!ses1 & ( _! consequ5ces4 ,recomb9ation ( mat]ial4--,"o o!r peculi>ity ( ! accretion hypo!sis mu/ be recall$ "h4 ,! incom+ bodies mu/ probably be assum$ to h fall5 9 promiscu\s ord]1 & h5ce to h be5 indiscrim9ately m+l$ 9 ! gr[+ e>?4 ,z !y became buri$ deep] & deep] & _! temp]atures & pressures 7 rais$1 mu* recomb9ation1 *emical & physical1 may be presum$ to h foll[$4 ,z already not$1 ^! *anges w\ld probably give increas$ d5sity 9 ! ma94 ,! mat]ial be+1 h[ev]1 9 a solid /ate1 ! re>rangem5t w\ld be sl[ & its p]si/5ce 9 "t indet]m9ate1 & x may yet be f> f complete4 ,x is n improbable1 !re=e1 "u ?is hypo!sis1 t "s notable "p ( ! rec5t %r9kage ( ! e>? has be5 due to ! cont9u$ re>rangem5t ( its het]og5e\s int]nal matt]4 ,?is w\ld n be equally s 9 an e>? d]iv$ f a molt5 mass1 = ! requir$ adju/m5ts ( ! mat]ial %\ld h tak5 place :ile 9 ! fluid /ate be=e solidification4 ,comp>ison ( ! hypo!ses4--,by comp>+ ! ?ree hypo!ses ( ! e>ly /ates ( ! e>?'s temp]ature1 x w be se5 t !re is a radical diff]5ce1 !rmally1 betwe5 ! fir/ & ! la/ two4 ,! fir/ assumes a ne>ly uni=m di/ribution ( int]nal temp]ature1 & h5ce1 ow+ to ! exce$+ly sl[ rate ( conduction1 limits ! movem5ts & de=mations ( ! cru/1 s f> z dep5d5t on heat1 to v sup]ficial horizons4 ,! second & ?ird views agree 9 po/ulat+ *anges ( temp]ature 9 ! deep portions1 z well z 9 ! sup]ficial1 & h5ce involve ! c5tral portion ( ! e>? 9 ! great movem5ts & de=mations4 ,x is n to be suppos$ t ?is ( itself necess>ily increases ! sum-total ( ! effects ( contraction1 =1 giv5 a c]ta9 loss ( heat f ! surface1 x may be relatively immat]ial :e!r ?is loss arose f a l>ge r$uction ( temp]ature 9 a %all[ zone1 or a small r$uction ( temp]ature 9 a deep zone1 =1 except z ! coeffici5t ( expansion v>ies1 ! total %r9kage w\ld be ! same4 ,b ! diff]5ce 9 di/ribution makes a radical diff]5ce 9 ! result+ movem5ts1 =1 9 ! fir/ case1 ! movem5ts are 9 a weak sup]ficial %ell t _c accumulate great /resses1 & h5ce mu/ yield practically z fa/ z ! /resses arise1 :ile1 9 ! second case1 ! /ress-accumulat+ p[] ( ! ?ick segm5ts may be great1 & ! /resses may ga!r = long p]iods & give rise to great cumulative results at long int]vals4 ,9 ?is respect ! la/ two views h mu* 9 common1 ?\gh !y diff] 9 o!r important p>ticul>s4 ,) ?is g5]al backgr\nd ( hypo!sis1 we may n[ turn to ! direct evid5ces ( ! di/ribution ( int]nal temp]ature :i* obs]vations ne> ! surface af=d4 ,un=tunately !y are limit$ to a m]e film1 z x 71 little m ?an ( ! radius ( ! e>?4 ,,obs]v$ ,,temp]atures ,,9 ,,excavations4 ,z ! e>? is p5etrat$ bel[ ! zone ( seasonal *anges by wells1 m9es1 tunnels1 & o!r excavations1 ! temp]ature is almo/ inv>iably f\nd to rise4 ,! rate ( rise1 h[ev]1 is f> f uni=m4 ,if we set aside z exceptional ! unusually rapid rise ne> volcanoes & 9 o!r localities ( obvi\s igne\s influ5ce1 ! highe/ rates are /ill six times ! l[e/4 ,a l>ge numb] ( records h be5 collat$ by ! ,committee on ,und]gr\nd ,temp]atures1 ( ! ,briti% ,association = ! ,advancem5t ( ,sci5ce4 ,^! range f #a ,f4 9 less ?an #bj feet to #a ,f4 9 #acj feet1 ) an av]age ( #a ,f4 9 #ej to #fj feet1 :i* has usually be5 tak5 z repres5tative4 ,! m rec5t deep bor+s t h be5 c>efully measur$ ) due reg>d to s\rces ( error indicate a sl[] rate ( rise4 ,"s ( ! m notable records are z foll[s3#a ,dep?4 ,rate ( rise4 ,sp]5b]g bore 7,g]many7 #cdib feet4 #a ,f4 9 #ea4e feet4 ,s*ladeback bore 7,g]many7 #efcj #a ,f4 9 #fg4a ,cremorne bore 7,n4 ,s4 ,wales7 #bibi #a ,f4 9 #hj ,p>us*[itz bore 7,upp] ,silesia7 #fdjh #a ,f4 9 #fb4b ,:eel+ well 7,w4 ,va47 #ddfb #a ,f4 9 #gd4a ,/4 ,go?>d tunnel 7,italy-,switz]l&7 #eegh #a ,f4 9 #hb ,mt4 ,c5is tunnel 7,france-,italy7 #ebhj #a ,f4 9 #gi ,tam>ack m9e 7,n4 ,mi*47 #ddej #a ,f4 9 #ajj #beg ,calumet & ,hecla m9e 7,n4 ,mi*47 #dici #a ,f4 9 #ajc #beg ,ditto1 betwe5 #ccbd feet & #dhcg feet #a ,f4 9 #ic4d ,x is to be not$ t ev5 ^! select$ records v>y a hundr$ p] c5t4 ,v notable v>iations are f\nd 9 ! same m9e or well1 & (t5 mu* diff]5ce is f\nd 9 adjac5t records1 especially ^? ( artesian wells4 ,"s ( ^! are expla9able1 b ! full mean+ ( o!r v>iations is yet to be f\nd4 ,explanations ( v>y+ increm5t4--,c]ta9 app>5t v>iations are m]ely due to inequalities ( topography4 ,! isogeo!rms1 or planes ( equal und]gr\nd temp]ature1 d n normally rise & fall ) e local irregul>ity ( ! surface1 b m ne>ly /rike an av]age4 ,a well on a bluff #ejj feet high w\ld probably rea* ne>ly ! same temp]ature at #ajjj feet1 z a well #ejj feet deep 9 ! adjac5t valley1 giv+ a gradi5t twice z great 9 ! "o case z 9 ! o!r4 ,9 int]pret+ ! temp]atures ( artesian fl[s1 reg>d mu/ be _h to ! dep?s ( rock "u :i* ! wat]s h pass$1 z well z ! dep?s at ! location ( ! wells4 ,d>ton has f\nd#beh unusually high & v>y+ temp]atures 9 ! artesian wells ( ! ,dakotas1 "s "p ( :i* may be due to ?is cause1 ?\gh a full explanation ( _! s+ul> v>iations is n yet rea*$4 ,! p]meation & circulation ( wat] affect ! temp]ature 9 two important ways3 7#a7 wet rocks are bett] conductors ?an dry ones1 & 7#b7 ! convective movem5t ( wat] is a means ( convey+ heat f l[] to high] horizons4 ,z ! circulation ( und]gr\nd wat] is v unequal1 mu* irregul>ity ( !rmal di/ribution 9 ! upp] zones probably arises f ?is s\rce4 ,! g5]al effect ( wat] circulation is to r$uce ! !rmal gradi5t :]e ! circulation is relatively rapid1 z x is ne> ! surface & 9 ! ma9 ?or\ghf>es ( circulation1 & h5ce to cause a relatively rapid rise 9 ! gradi5t j bel[ ! zone ( effective wat] influ5ce4 ,"s records con=m to ?is !oretical d$uction1 b 9 g5]al x is mask$ by o!r influ5ces4 ,*emical action1 especially oxidation1 c>bonation1 hydration1 solution1 & precipitation1 modify ! normal temp]ature gradi5t1 b h[ effectively is n well det]m9$4 ,) little d\bt ! fir/ ?ree m5tion$ above raise ! temp]ature1 :ile solution & precipitation 9 "s l>ge measure (fset ea* o!r4#bei ,! sum-total is probably an appreciable rise 9 temp]ature4 ,x has ev5 be5 conjectur$ t ! heat ( volcanic action is due to *emical comb9ation 9 ! l[] rea*es ( wat] circulation1 b ?is is obvi\sly an ov]-e/imate4 ,diff]5ces 9 ! conductivity ( rock are an obvi\s s\rce ( v>y+ und]gr\nd temp]ature gradi5ts4 ,if an out] =mation conducts heat m freely ?an ^? bel[1 x t5ds to l[] ! gradi5t )9 itself & to cause a relative rise 9 ! gradi5t j bel[4 ,if a l[] =mation is m conductive ?an t above1 x t5ds to l[] ! gradi5t )9 itself1 & to raise x 9 ! "o above1 because x c>ries heat to ! out] "o fa/] ?an ! latt] c>ries x away4 ,! compression to :i* rocks h be5 subject$ affects _! temp]ature4 ,at ! surface ! v>iation f ?is s\rce is *iefly dep5d5t on ! lat]al ?ru/ suff]$4 ,:5 all[ances are made = all ^! & o!r kn[n causes ( local v>iation ( temp]ature1 x is /ill n cle> t a uni=m av]age gradi5t rema9s z ! true conception4 ,if ! e>? 7 once a molt5 sph]oid1 !re w\ld be a /rong presumption t1 aside f local v>iations1 !re w\ld be a normal curve applicable to all regions4 ,on ! o!r h&1 if ! int]nal heat has aris5 *iefly f compression1 & if ! compression has v>i$ 9 diff]5t regions1 z ! inequalities ( ! surface r5d] probable1 !re w\ld be no su* def9ite normal curve 9 ! accessible zone ( ! e>?1 b r a v>y+ rate 9 diff]5t regions4 ,9 ei!r case1 ! lat] movem5ts1 compressions & /ra9s ( ! cru/1 mu/ modify ! orig9al !rmal gradi5ts4 ,gradi5ts project$4--,x is n probable t ^! gradi5ts1 ev5 :5 correct$ = local v>iations1 cont9ue unmodifi$ to ! c5t] ( ! e>?4 ,if !y did1 #a ,f4 9 #fj feet cont9u$ to ! e>?'s c5t] w\ld give #cdh1jjj ,f41 & #a ,f4 9 #ajj feet w\ld give #bji1jjj ,f4 ,x is mu* m probable t ! rates ( rise fall away bel[ ! sup]ficial zone4 ,if wat] circulation 9 ! fracture zone is ! mo/ effici5t ag5cy coop]at+ ) conductivity 9 ! outw>d conveyance ( heat1 z seems probable1 ! gradi5t 9 t zone %\ld rise at an abnormal rate1 & h5ce ! av]age gradi5t 9 ! deep] portions n affect$ by ?is circulation %\ld be l[]4 ,x w be recall$ t ! c5tral temp]ature d$uc$ f an ext5sion ( ,b>us' fusion curve is #acf1hjj ,f4 7#gf1jjj ,c471 :i*1 high z x is1 gives a l[] av]age gradi5t ?an ! surface obs]vations4 ,! computations f compression by ,lunn1 giv+ a c5tral temp]ature ( #cf1jjj ,f4 7#bj1jjj ,c471 imply a /ill l[] av]age rate1 :ile ! convection hypo!sis po/ulates no s5sible increase at all bel[ #bjj or #cjj miles4 ---------------------------------------- --------------------------------- ,av]age mat]ial ,m9]al ( cru/ ,norm m9]als equival5t ,l9e> ,volume 7,cl>ke's calculat$ f 7,c4,i4,p4,w4 ,axis4 expansion4expansion4 tables74#bfj ,cl>ke's av]age4 sy/em74 ---------------------------------------- --------------------------------- ,si,o #eh4ei ,qu>tz #aa4d,qu>tz 4#jjjjabjf 4#jjjjcfah ,al,o #ae4jd ,or?oclase #ag4b a 4#jjjjaijf ,fe,o #c4id ,albite #bg4c;,anor?ite b -4#jjjjjbjce ,fe,o #c4dh ,anor?ite #ag4h c -4#jjjjjadie4jjjjaeec ,ca,o #e4bi ,diopside #f4h a 4#jjjjjhabe ,mg,o #d4di ,hyp]/h5e #aj4b;,diopside b 4#jjjjafifc4jjjjbcd ,k,o #b4ij ,magnetite & c -4#jjjjjagjg ,na,o #c4bj ,ilm5ite #f4h;,augite a 4#jjjjachef ,ti,o 4#ee ,m9or 7us$ = con/itu5ts hyp]/h5e7 ,m9or omitt$ #b4e con/itu5ts ------------ b 4#jjjjjbgb 4#jjjjbde omitt$ #b4eb #ajj4jj,magnetite c 4#jjjjjgia ------------ 4#jjjjjiedj4jjjjbhfb #ajj4jj ---------------------------------------- --------------------------------- ,! am\nt ( loss ( heat4--,! am\nt ( loss ( int]ior heat :i* ! e>? suff]s may be e/imat$ by t :i* is obs]v$ to be pass+ outw>d ?r\gh ! rock1 or by comput+ ! am\nt :i* %\ld be convey$ outw>ds ) ! e/imat$ gradi5ts & ) ! conductivity ( rock z det]m9$ by exp]im5t4 ,! latt] me?od is usually employ$ 9 g5]al problems4 ,tak+ ! mean !rmometric conductivity ( rock z #j4jjde1 ! gradi5t z #a ,c4 9 #cj met]s1 ! av]age specific heat ( rock z #j4e small calories p] cubic c5timet]1 x is comput$ t 9 #ajj1jjj1jjj ye>s ! loss ( heat w\ld am\nt to #de ,c4 7#ha ,f47 = ! :ole body ( ! e>?4#bfa ,tait makes ! m cons]vative e/imate ( #aj ,c4 7#ah ,f47 9 ! same p]iod4#bfb ,?is is an exce$+ly small result1 & emphasizes ! l[ conductivity ( rock4 ,! am\nt ( %r9kage f loss ( heat4--,to compute ! am\nt ( %r9kage = a giv5 am\nt ( cool+1 ! av]age coeffici5t ( expansion ( rock is requir$4 ,?is has be5 exp]im5tally det]m9$ by sev]al inve/igators4 ,by comb9+ ! det]m9ations ( o!rs ) 8 own1 ,t4 ,mell>d ,reade f\nd ! l9e> coeffici5t to be 4#jjjjjebeg p] #a ,f41 equival5t to 4#jjjjbhch p] #a ,c4 p] volume4 ,9 ?is ! proportions ( ! diff]5t rocks 9 ! cru/ 7 r\ghly e/imat$4 ,to secure an indep5d5t result f ! be/ available e/imate ( :at con/itutes ! av]age rock1 ,w4 ,h4 ,emmons has r$uc$ ,cl>ke's av]age ( ! *emical con/itu5ts ( ! cru/ to ! norm m9]als "u ! new sy/em ( ,cross1 ,idd+s1 ,pirsson1 & ,wa%+ton 7see p4 #ded7 & made a weight$ av]age ( ! conductivities ( ^!1 z %[n 9 ! foll[+ table3 ---------------------------------------- ------------------- ,volume ,volume ,p]c5tages ,sp4 ,gr4 proportions proportions ( norm ( norm ( norm ( temp4 m9]als4 m9]als4 m9]als4 #a ,c4 high]4 ---------------------------------------- ------------------- ,qu>tz #aa4d #b4ff #d4bh #d4bhjaedhejd ,feldsp>s#bfc #fb4c #b4g #bc4jg #bc4jgjcehbgga ,diopside #f4h #c4c #b4jf #b4jfjjdhbjdj ,hyp]/h5e #aj4b #c4de #b4ie #b4iejjgbbgej ,magnetite #f4h #e4ag #a4c #a4cjjjcgbjfj -------- ---------- ------------- ,total #ig4e #cc4ff #cc4ffjfgjhabe ---------------------------------------- ------------------- ,subtract+ ! /at$ volume f ! volume at a temp]ature ( #a ,c4 high]1 ! diff]5ce is f\nd to be 4#jjjfgjhabe1 :i* divid$ by ! volume gives 4#jjjjaii1 :i* is ! coeffici5t ( expansion ( ! !oretical1 av]age1 surface rock ( ! e>?4 ,) ?is coeffici5t1 ! radial %r9kage result+ f an av]age loss ( #aj ,c4 7#ah ,f471 7,tait's e/imate71 is a little ov] a qu>t] ( a mile 74#begb72 & = a loss ( #de ,c4 7#ha ,f471 7e/imate ( ,daniell's ,physics71 a little ov] a mile 7#a4aegd74 ,! %ort5+ ( ! circumf]5ce = #aj ,c4 loss is #a4f miles1 & = #de ,c41 #g4bg miles4 ,computations bas$ on ! coeffici5t ( expansion adopt$ by ,reade give #b4ce miles circumf]5tial %ort5+ = a loss ( #aj ,c4 & #aj4e miles = a loss ( #de ,c4 ,9 bo? ^! cases1 ! :ole contraction is assum$ to take a v]tical direction1 & h5ce ^! are maximum results4 ,!y are exce$+ly small4 ,unless !re is a v s]i\s error 9 ! e/imat$ rate ( !rmal loss1 or 9 ! coeffici5ts ( expansion1 cool+ w\ld seem to be a v inadequate cause = ! %r9kage :i* ! m\nta9 fold+s1 ov]?ru/ faults1 & o!r de=mations imply4 ,?is inadequacy has be5 /rongly urg$ by ,fi%]#bfd & by ,dutton4#bfe ,9 view ( ! app>5t incompet5cy ( ext]nal loss ( heat1 ! possibilities ( di/ortion f o!r causes invite consid]ation4 ,,o!r ,,s\rces ,,( ,,de=mation4 ,transf] ( int]nal heat4--,x is !oretically possible t de=mation ( ! subcru/ may result f ! int]nal transf] ( heat )\t reg>d to ext]nal loss4 ,x has already be5 %[n 7p4 #eci7 t "u c]ta9 possible conditions m heat w\ld fl[ f ! inn] p>ts to high] horizons ?an w\ld be convey$ ?r\gh ^! latt] to ! surface & !re lo/1 & t1 z a result1 ! temp]atures ( ! inn] p>ts might be fall+1 :ile ^? ( ! out] p>ts 7except ! surface7 might be ris+4 ,) ! m cons]vative coeffici5t ( expansion previ\sly giv51 a l[]+ ( ! av]age temp]ature ( ! inn] half ( ! e>? #ejj ,c4 & ! rais+1 by transf]1 ( ! out] half to an equal am\nt w\ld give a lat]al ?ru/ ( ab\t #hc miles1 :i* is ab\t ! ord] ( magnitude ?\ght to be ne$$4 ,x is n affirm$ t ?is takes place1 b "s transf] ( ?is k9d is among ! !oretical possibilities "u ! accretion hypo!sis4 ,! process c\ld n cont9ue indef9itely2 b1 = aught t c n[ be affirm$1 x may /ill be 9 progress4 ,d5s] aggregation ( matt]4--,z already not$1 matt] "u int5se pressure t5ds to aggregate itself 9 ! =ms t give ! greate/ d5sity4 ,if ! e>? 7 built up ( het]og5e\s matt] arrang$ at haphaz>d1 ! mat]ial w\ld probably readju/ itself m or less1 z "t w5t on1 into comb9ations ( great] & great] d5sity4 ,?is process may be "o ( ! important s\rces ( %r9kage1 = an av]age *ange ( d5sity ( #a p]c5t41 affect+ ! matt] ( ! :ole globe1 w\ld probably meet all ! dem&s ( de=mation s9ce ! beg9n+ ( ! ,paleozoic p]iod4 ,extravasation ( lavas4--,x is obvi\s t if lavas are =c$ out f b5ea? ! cru/ & spread ^u x1 a comp5sat+ s9k+ ( ! cru/ w foll[4 ,?is1 h[ev]1 is r a mode ?an an ult]ior cause1 = a cause mu/ be f\nd = ! extrusion ( ! lavas1 & ?is cause may be "o ( ! o!r ag5cies recogniz$1 su* z a transf] ( heat1 a reorganization ( matt]1 or a *ange ( pressure4 ,! m practical "q1 h[ev]1 relates to its compet5cy4 ,c ! am\nt ( lava t has be5 extrud$ h _h any v appreciable effect on ! desc5t ( ! cru/8 ,! great ,deccan fl[ is cr$it$ ) an area ( #bjj1jjj squ>e miles1 & a ?ickness ( #djjj to #fjjj feet4 ,va/ z ?is is = a lava-fl[1 x w\ld =m a lay] only ab\t #e feet ?ick :5 spread ov] ! :ole surface ( ! globe1 & h5ce ! s9k+ to replace x w\ld cause a lat]al ?ru/1 on any great circle1 ( ab\t #ca feet only4 ,x requires a v g5]\s e/imate ( ! lavas p\r$ out betwe5 any two great m\nta9-mak+ p]iods s9ce ! beg9n+ ( ! well-kn[n /ratigraphic s]ies to cause a horizontal ?ru/ ( any appreciable "p ( t involv$ 9 m\nta9-mak+4 ,! case is diff]5t1 h[ev]1 if we g back to ! ,ar*ean era1 9 :i* ! proportion ( extrusive & intrusive rocks is v high4 ,v notable di/ortion may !n be assign$ to ! extravasation ( lavas4 ,! outw>d movem5t ( lava mu/ also be cr$it$ ) "s transf] ( heat f l[] to high] horizons1 & ?is is probably "o ( ! ag5cies t h produc$ ! relatively high und]gr\nd temp]atures 9 ! out] "p ( ! e>?4 ,if lavas are ?ru/ into crevices ( ! cru/ !y contribute to its ext5sion1 b causes = ! crevices & = ! intrusion mu/ be f\nd1 & ^! are probably only expressions ( "o or ano!r ( ! m g5]al ag5cies4 ,*ange 9 ! rate ( rotation4--,z previ\sly not$1 ! tide acts z a brake on ! rotation ( ! e>?4 ,! oblat5ess ( ! pres5t e>? is accommodat$ to its pres5t rate ( rotation4 ,x is assum$ t su* accommodation has always obta9$1 & t if ! rotation has *ang$1 ! =m ( ! e>? has *ang$ also4 ,n[1 ! m oblate ! sph]oid1 ! l>g] its surface %ell & ! less ! total =ce ( gravity4 ,h5ce if ! e>?'s rotation has dim9i%$1 its cru/ mu/ h %runk1 because ! =m ( ! sph]oid has become m compact1 & ! increase ( gravity has increas$ its d5sity4 ,!re is at pres5t a wat]-tide *iefly g5]at$ 9 ! s\!rn ocean1 & irregul>ly di/ribut$ to m nor!rly wat]s4 ,?is irregul>ity int]f]es ) its sy/ematic action z a brake1 & its av]age effects are difficult ( e/imation4 ,! wat]-tides ( pa/ ages are /ill m unc]ta91 z !y mu/ h dep5d$ on ! configuration & cont9uity ( ! oceans4 ,!re are geological gr\nds = ! belief t ! s\!rn ocean 0 int]rupt$ by l& dur+ portions ( ! pa/ at lea/1 & x is unkn[n :e!r !re 7 else:]e ocean-belts well suit$ to ! g5]ation ( l>ge tides4 ,! ocean-tide1 !re=e1 furni%es a v unc]ta9 basis = e/imat+ ! ret>dation ( rotation4#bff ,! !oretical case re/s l>gely on ! assumption ( an effective body-tide4 ,! e>? d\btless has "s body-tide1 b :e!r x is suffici5tly great to be effective1 & :e!r its position1 :i* dep5ds on its promptness 9 yield+ & 9 resili5ce1 is favorable to ! ret>dation ( rotation1 are yet op5 que/ions4 ,! exi/5ce ( an appreciable body-tide has n yet be5 prov$ by obs]vation4 ,g4 ,h4 ,d>w91 assum+ t ! e>? is visc\s en\gh to give a body-tide ( appreciable value & ( effective position1 has d$uc$ a s]ies ( =m] rates ( rotation ( ! e>? & has comput$ ! correspond+ di/ances ( ! moon4#bfg ,c4 ,s4 ,sli*t] has %[n t ! less5+ ( ! area ( ! surface & ! increase ( ! =ce ( gravity correspond+ to ^! assign$ *anges ( rotation are l>ge1 & t if ! *anges 7 actually exp]i5c$ !y mu/ h involv$ mu* di/ortion ( ! cru/4#bfh ,^! di/ortions w\ld1 h[ev]1 be ( a peculi> nature1 & %\ld !reby be detectible1 if !y 7 realiz$2 = 9 pass+ f a m oblate to a less oblate sph]oid1 ! equatorial belt %r9ks1 & ! pol> tracts rise & become m convex4 ,wr9kles %\ld1 !re=e1 m>k ! equatorial belts1 & t5sion ! high latitudes4 ,sli*t] has comput$ t 9 a *ange f a rotation p]iod ( #c4hb h\rs to ! pres5t "o1 ! equatorial belt mu/ %ort5 #aaca miles & ! m]idional circles l5g!n #die miles4 ,if we take ,heim's e/imate ( ! cru/-%ort5+ involv$ 9 =m+ ! ,alps--#gd miles--z a /&>d1 ! #aaca miles ( equatorial %ort5+ w\ld be suffici5t = ! =mation ( #ae m\nta9 ranges ( ,alp9e magnitude4 ,if1 z "s geologi/s urge1 ! e/imate ( m\nta9 fold+ is too great1 ! quoti5t w\ld be /ill l>g]4 ,^! ranges %\ld run across ! equator & be limit$ to ab\t #cc ,n4 & ,s4 latitude4 ,! high-latitude t5sion w\ld be suffici5t to cause ! e>? to gape m ?an two hundr$ miles at ! poles1 if !re 7 simple ideal %r9kage4 ,! am\nts & ! di/ribution ( ?ru/ & %r9kage are %[n 9 ,fig4 #dec4 ,if ! *ange ( rotation 7 no m ?an f #ad h\rs to ! pres5t rate1 !re w\ld /ill be #eb miles ( ?ru/ 9 ! equatorial belt1 & #dj miles ( %ortage 9 ! m]idional circles4 ,!re are no cle> signs ( su* a rem>kable di/ribution ( ?ru/ & t5sion z ?is hypo!sis requires4 ,m\nta9s are ab\t z abundant & z /rong nor? ( #cc1 ! neutral l9e1 z s\? ( x1 & !y ext5d to high latitudes4 ,! ,ar*ean rocks1 9 :i* ?is ag5cy %\ld h be5 mo/ effective because ( _! e>ly =mation1 are crumpl$ & cru%$ 9 ! high latitudes mu* ! same z 9 l[ latitudes4 ,fur!rmore1 if !re _h be5 appreciable *ange 9 ! =m ( ! e>? to accommodate itself to a sl[] rotation1 ! wat] on ! surface1 be+ ! mo/ mobile elem5t1 %\ld h ga!r$ t[>d ! poles1 & ! less mobile solid e>? %\ld h protrud$ ab\t ! equator1 b ! di/ribution ( l& & wat]1 pres5t & pa/1 gives no cle> evid5ce ( ?is4 ,! equatorial belt conta9s a less p]c5tage ( l& ?an ! area nor? ( x & m ?an t s\? ( x4 ,x v>ies b slightly f ! av]age = ! :ole globe4 ,illu/ration3 ,fig4 #dec4--,pol> projection ( ! e>?'s hemisph]e %[+ ! !oretical high-latitude t5sion & l[-latitude compression involv$ 9 a *ange ( rotation f #c4hb h\rs to ! pres5t rate4 ,! figure is drawn to true scale z se5 f a po9t above ! pole1 & 9 consequ5ce ! equatorial tract is =e%ort5$4 ,! black triangles %[ compression r$uc$ 9 l5g? by =e%ort5+2 ! :ite %[ t5sion 9 ess5tially true proportions to ! high-latitude areas4 ,! neutral l9e betwe5 ! areas ( compression & ( /ret*+ lies at #cc #bj latitude4 ,:ile ! doctr9e ( tidal ret>dation is !oretically s\nd1 & :ile ! relations ( ! moon to ! e>? h probably be5 appreciably affect$ by tidal action1 geological evid5ce indicates t x has n be5 suffici5tly effective 9 produc+ cru/al de=mations to be cle>ly detect$ by its own di/9ctive results4 ,?is may be due 7#a7 to ! fact t !re are comp5sat+ ag5cies t t5d to accel]ation ( rotation1 & 7#b7 to ! probable fact t ! c5tral rigidity ( ! e>? is too high to give a v effective body-tide4 ,h5ce ! process ( ret>dation may h be5 too sl[ to h be5 geologically appreciable 9 ! kn[n p]iod4 ,! rec5t e/imates ( ! effective rigidity ( ! e>? are great] ?an =m] ones1 & !y may ne$ to be modifi$ yet fur!r 9 ! same direction4 ,di/ribution ( rigidity4--,an important consid]ation 9 ?is connection is ! di/ribution ( int]ior rigidity4 ,x is c]ta9 t ! rigidity ( ! out]mo/ "p1 tak5 z a mass1 is some:at less ?an t ( rock ( an av]age surface type1 = x is fissur$1 & !re is no reason to suppose t ! rigidity ( ! rock next bel[ ! fissure zone rises at once to ! rigidity ( /eel1 & h5ce if ! av]age rigidity ( ! :ole e>? is equal to t ( /eel1 a portion ( ! int]ior mu/ h a rigidity mu* high] ?an /eel4 ,!re is probably "s law ( increase f surface to c5t]1 & !re are !oretical gr\nds = ?9k+ t x is 9 "s way connect$ ) ! laws ( pressure1 d5sity1 compressibility1 & temp]ature4 ,all ( ^! factors probably affect rigidity1 b 9 diff]5t ways4 ,! modulus ( rigidity ( /eel is ab\t #ggj #aj grms4 p] sq4 cm4 ,milne & ,gray#bfi f\nd t ( granite to be #abh #aj4 ,! ratio ( ! rigidity ( /eel to t ( rock is1 !re=e1 ab\t #f 3 #a4 ,if x be assum$ t ! rigidity increases 9 dep? directly z ! d5sity1 ! rigidity w n[h]e rea* t ( /eel1 be+ only ab\t two-?irds z mu* at ! c5t]4 ,if x be assum$ t ! rigidity increases z ! squ>es ( ! d5sity ratios1 ! foll[+ values are obta9$3 ---------------------------------------- ---------------------- ,di/ances f ,d5sity c5t] 9 t]ms ,d5sities "u ,d5sity ratios ,d$uc$ ( radius4 ,laplace's law4 ratios4 squ>$4 rigidities4 ---------------------------------------- ---------------------- #a4jj #b4h #a #a #j4af ,/eel 4#ge #e4g #b #d #j4f 4#ej #h4ci #c #i #a4e 4#be #aj4bg #c4g #ac4g #b4c 4#jj #aj4ie #c4i #ae4b #b4e ,^! values seem fairly consi/5t ) ! app>5t requirem5ts ( ! case4 ,if ! di/ribution ( rigidity 7 ( ?is nature1 ! av]age rigidity w\ld be mu* less ?an t ( /eel1 = m ?an half ! volume lies 9 ! out] division1 betwe5 #a4jj & 4#ge radius1 & yet ! effective resi/ance to tidal de=mation w\ld be high1 =1 accord+ to ,g4 ,h4 ,d>w91#bgj ! tidal /ress-diff]5ces are eight times z great 9 ! c5t] z at ! surface4 ,! rigidity w\ld1 !re=e1 be di/ribut$ s z to be mu* m effective 9 resi/ance ?an if x 7 uni=m4 ,! sugge/ion arises "h t ! tidal /resses & o!r analog\s /resses aris+ f a/ronomical s\rces may be 9 !mselves ! causes ( "s su* di/ribution ( rigidity z ?is4 ,! tidal /resses are rhy?mical & give rise to a k9d ( knead+ ( ! body ( ! e>?1 small 9 measure to be sure1 b p]si/5t & rapidly recurr5t4 ,s9ce ^! /ress-diff]5ces at ! c5t] are eight times ^? at ! surface1 & s9ce also ! gravitative /ress at ! c5t] is #c1jjj1jjj times t at ! surface1 !re is a s]ies ( p]si/5tly recurr+ /ress-diff]5ces1 greate/ at ! c5t] & decl9+ outw>ds1 sup]pos$ on enorm\s /atic /resses1 also int5se/ at ! c5t] & decl9+ outw>ds4 ,n[1 if ! e>? mat]ial 7 once made up ( a mixture ( m9]als ( diff]5t fusibility1 "s ( :i* became m mobile 7:e!r fluid or visc\s7 ?an o!rs "u ! ris+ temp]ature ( ! int]ior1 x seems t ! m mobile portion mu/ h t5d$ to move f ! regions ( great] /ress-diff]5ces to ^? ( less] /ress-diff]5ces4 ,! p]si/5ce & ! rhy?mical nature ( ! tidal /ress-diff]5ces seem well suit$ to aid ! mobile p>ts 9 gradually work+ _! way outw>ds4 ,at ! same "t ! m solid & resi/ant portions %\ld rema9 beh9d1 & ?us come to con/itute ! dom9ant mat]ial ( ! c5tral regions :]e /ress-diff]5ces 7 greate/1 & s1 z x 71 conc5trate rigidity !re4 ,! process may /ill be 9 action4 ,if x be assum$ t ! rhy?mical /resses h ?us develop$ a resi/ance to de=mation proportional to _! int5sity1 we may comb9e ?is ) d5sity to =m ! basis ( ano!r hypo!tical di/ribution ( rigidity1 z foll[s3 ---------------------------------------- ----------------------- ,di/ances f ,d5sities ,d5sity ,ratios adju/$ c5t] 9 t]ms "u ratios4 to /ress ,d$uc$ ( radius4 ,laplaces diff]5ces4 rigidities4 ,law4 7#a3h7 ---------------------------------------- ----------------------- #a4jj #b4h #a #a #j4af ,/eel 4#ge #e4g #b #c4e #j4eh 4#ej #h4ci #c #e4d #j4ij 4#be #aj4bg #c4g #g #a4af 4#jj #aj4ie #c4i #h #a4cc ,! av]age rigidity is "h also mu* less ?an t ( /eel1 b its di/ribution is su* z to r5d] x ideally fitt$ to resi/ tidal di/ortion4 ,^! hypo!tical di/ributions ( rigidity h no claims to special value 9 !mselves1 = ! gr\nds on :i* !y are bas$ are q inadequate1 b !y are n )\t importance 9 giv+ tangible =m to consid]ations t be> vitally n only on tidal problems1 b on _m o!rs connect$ ) ! int]nal con/itution & dynamics ( ! e>?4 ,sph]icity z a factor 9 de=mation4 ,x is obvi\s t if ! e>? %r9ks1 its cru/ mu/ become too l>ge = ! r$uc$ sph]oid1 & mu/ be compress$ or di/ort$ to fit ! new =m4 ,! am\nt ( di/ortion requir$ = any giv5 %r9kage is easily comput$ f ! ratio ( ! radius to ! circumf]5ce ( a sph]e1 :i* is approximately #a 3 #f4bh4 ,if1 = example1 ! radius %ort5s #e miles1 ea* great circle mu/ on ! av]age be compress$1 wr9kl$1 or o!rwise di/ort$ to ! ext5t ( ab\t #ca miles1 or1 9 rev]s$ application1 if ! m\nta9 fold+s on any great circle toge!r %[ a %ort5+ ( #ajj miles1 ! appropriate radial %ort5+ is #af miles4 ,! ratio ( #a 3 #f furni%es a conv5i5t *eck on hypo!ses t assign specific ?ru/s to specific s9k+s ( adjac5t segm5ts4 ,a segm5t #cjjj miles across1 = example1 su* z ! bottom ( ! ,nor? ,atlantic bas91 s9k+ ?ree miles1 ab\t ! full dep? ( ! bas91 w\ld give a lat]al ?ru/ ( ab\t #b4b miles1 a little ov] a mile on ea* side1 a trivial am\nt comp>$ ) ! fold+s on ! adjac5t cont95tal bord]s4 ,! influ5ce ( ! dom$ =m ( ! surface4--,because ( ! sph]oidal =m ( ! e>?1 ea* portion ( ! cru/ is ideally an ar* or dome4 ,:5 broad areas l ! cont95ts are consid]$1 x is ! dome r ?an ! ar* t is involv$1 & 9 ?is ! ?ru/ is ideally t[>d all p>ts ( ! p]iph]y4 ,x is probably = ?is reason t m\nta9 ranges s (t5 foll[ curv$ or angulat$ l9es1 or outl9e rude triangles or polygons4 ,! sigmoidal c\rses ( ! ranges ( s\!rn ,europe1 ! loop$ *a9s ( ! ea/]n bord] ( ,asia1 & ! curv$ ranges ( ! ,antillean region1 are notable examples4 ,! bord] ranges ( ! ,am]icas1 ( ! ,?ibetan plateau1 & ( o!r great segm5ts1 illu/rate ! polygonal t5d5cy4 ,! g5]al di/ribution ( ! great ranges is su* t a ne>ly equal portion ( cru/al crumpl+ is ?r[n across ea* great circle1 z !ory dem&s4 ,! common g5]alization t m\nta9 ranges run *iefly 9 oblique directions1 z nor!a/-s\?we/1 nor?we/-s\!a/1 is b a p>tial view ( ! m g5]al fact t ! l9es ( di/ortion mu/ lie 9 all directions to accommodate ! old cru/ to ! new geoid1 if !re be equable contraction 9 all p>ts4 ,!oretical /r5g? ( domes ( e>?-dim5sions4--,z ! dom$ =m ( ! cru/ has play$ an important "p 9 !ories ( de=mation1 x is important to =m quantitative conceptions ( ! /r5g? ( ideal domes hav+ ! figure & dim5sions ( segm5ts ( ! e>?'s cru/4 ,accord+ to ,hosk9s1#bga a dome correspond+ p]fectly to ! sph]icity ( ! e>?1 =m$ ( firm cry/all9e rock ( ! high cru%+ /r5g? ( #be1jjj p\nds to ! squ>e in*1 & hav+ a weight ( #ahj p\nds to ! cubic foot1 w\ld1 if unsupport$ bel[1 su/a9 only ( its own weight4#bgb ,?is result is ess5tially indep5d5t ( ! ext5t ( ! dome1 & also ( its ?ickness1 provid$ ! =m] is cont95tal & ! latt] does n exce$ a small fraction ( ! e>?'s radius4 ,if ?is ideal case be modifi$ by suppos+ ! c5tral "p ( ! sph]ical dome to rise above ! av]age surface1 ! support+ p[] w n be mat]ially *ang$ unless ! c5tral elevation is a consid]able fraction ( ! radius ( ! dome4 ,assum+ a c5tral elevation ( two miles--to repres5t ! protrusion ( ! cont95tal segm5ts--! results = domes ( diff]5t horizontal ext5t are z foll[s3#bgc ,,!oretical ,,/r5g? ,,( ,,ideal ,,domes ,,ar*$ ,,two ,,miles ,,above ,,! ,,av]age ,,surface ,,( ,,! ,,sph]e4 ---------------------------------------- ----------------- ,diamet] ( ,multipli] ( ,proportion ( its own giv5 dome i4e4 ! support+ weight su/a9$ by ar*$ #b miles proportion ( a giv5 dome ar*$ above sph]e4 sph]ical dome4 #b miles above sph]e4 ---------------------------------------- ----------------- #c1jjj miles #a4jjf #a_/ebb #djj 0 #a4cif #a_/cgf #bdj 0 #b4aa #a_/bdi #afj 0 #c4di #a_/aej #hj 0 #aj4ig #a_/dh ---------------------------------------- ----------------- ,f ?is table x w be se5 t = domes ( cont95tal dim5sions ! support+ /r5g? equals only a v small fraction ( ! dome's own weight4 ,increas+ ! ?ickness ( ! %ell increases its actual support+ p[]1 b ! proportion is some:at less :5 ! :ole sph]e is conc]n$4 ,! problem has n be5 work$ out = domes ( limit$ ext5t4 ,= r\gh e/imates1 :]e ! dim5sions ( ! dome are ( cont95tal magnitude1 ea* mile ( ?ickness may be tak5 z support+ a lay] ( ab\t #aj feet ( its own mat]ial4 ,if ! hypo!tical level ( no /ress be plac$ at #h miles dep?1 ! %ell above ?is1 by reason ( its dom$ %ape1 c\ld relieve its own pressure on t bel[ to an am\nt equal only to ! weight ( ab\t #hj feet ( rock ov] its surface1 ev5 if its =m & /ructure 7 ideal4 ,if ! %ell 7 ?ick en\gh 7#hag miles7 to embrace "o-half ! volume ( ! e>?1 its support+ p[] w\ld be a little m ?an ! weight ( "o & "o-half miles ( rock4 ,z ! radius ( ! e>? is less ?an #djjj miles1 ! extreme support+ p[] reckon$ on ?is basis w\ld be only ab\t #h miles ( rock-dep?4 ,x is int]e/+1 if n significant1 to obs]ve t ?is dep? b>ely rea*es ! m9imum %r9kage t w s]ve1 accord+ to curr5t e/imates1 to acc\nt = ! cru/al %ort5+ ( ! great m\nta9-mak+ p]iods4 ,x is z if ! %r9kage /resses accumulat$ to ! full ext5t ( ! /ress-resi/+ p[] ( ! :ole sph]e1 & !n collaps$4 ,x is n safe1 h[ev]1 to give mu* weight to ?is co9cid5ce1 = high] d5sities & probably high] resi/ances to di/ortion come into play 9 ! deep] horizons4 ,if ^! resi/ances are proportional to ! high] d5sities ( ! int]ior1 ! d$uctions w\ld rema9 ! same4 ,if ! effective rigidity ( ! e>? z a :ole is t ( /eel1 z d$uc$ by ,kelv9 & ,d>w9 f tidal & o!r obs]vations1 or twice t ( /eel1 z inf]r$ by ,milne f ! transmission ( seismic vibrations1 ! support+ p[] ( ! body ( ! e>? dep5d5t on its sph]icity w\ld be appreciably high]4 ,x w\ld seem cle> f ! =ego+ consid]ations t some?+ m ?an ! m]e cru/ ( ! e>? has be5 involv$ 9 ! great de=mations4 ,inde$ x is n cle> t ! fulle/ res\rces ( /ress-accumulation :i* ! sph]oidal =m ( ! e>? af=ds are suffici5t to meet ! dem&s ( ! problem1 unless ! rigidity ( ! e>? be tak5 at a mu* high] value ?an t ( surface-rock1 & ?is is p]haps an additional argum5t = ! high rigidities inf]r$ f tides & seismic waves4 ,9 view ( ! d\btful compet5cy ( ev5 ! ?icke/ segm5ts to accumulate ! requisite /resses1 !re is ne$ to consid] modes ( diff]5tial /ress-accumulation o!r ?an ^? dep5d5t on sph]icity4 ,/ress-accumulation indep5d5t ( sph]icity4--,! pr9ciple ( ! dome is br\ght into play :5ev] an int]ior %ell %r9ks away1 or t5ds to %r9k away1 f an out] "o :i* does n %r9k4 ,9 ?is case1 !re is a free out] surface & a m or less unsupport$ "u surface t[>d :i* motion is possible4 ,! dome may1 !re=e1 yield by cru%+ or by contortion4 ,! computations giv5 above are = cases ( ?is k9d4 ,b :]e ! ?ickness becomes great & ! dome involves a l>ge "p or ev5 all ( a sector ( ! e>?1 fre$om ( motion b5ea? is small1 & to readju/ ! matt] to a new =m1 /ra9s mu/ be develop$ widely ?r\gh\t ! sector1 & mu/ involve regions :]e ! pressure is extremely great on all sides1 & cru%+ 9 ! usual s5se impossible4 ,assum+ ! correctness ( ! mod]n doctr9e t su* pressure increases rigidity1 in/ead ( ! old] doctr9e t x gives pla/icity1 x becomes reasonable to assume t /ress-diff]5ces w\ld be di/ribut$ ?r\gh\t ! mass1 & br+ into play a l>ge portion ( its /ress-accumulat+ compet5cy4 ,:5 ! mass yield$1 x w\ld n be by cru%+1 b by 8fl[age10 :i* w\ld be m or less g5]al ?r\gh\t ! mass4 ,x might1 h[ev]1 be p>tially conc5trat$1 z1 = example1 on ! bord]s ( sectors ( diff]5t specific gravity4 ,/ress-diff]5ces may arise f physical *anges )9 ! rock itself4 ,:5ev] !re is a re-aggregation ( matt]1 or a *ange ( any k9d :i* involves *ange ( volume1 a *ange ( /ress is liable to be involv$4 ,x may be ( ! nature ( relief or ( int5sification4 ,9 an e>? built up by ! haphaz>d infall ( matt]1 a v het]og5e\s mass mu/ result1 & ! subsequ5t *anges may be suppos$ to be intimately di/ribut$ ?r\gh ! mass1 be+ slight at any po9t1 b pres5t at innum]able po9ts4 ,an immeasurable numb] ( small /ress-diff]5ces may1 !re=e1 be develop$ ?r\gh\t ! mass4 ,until ^! ov]mat* ! effective /r5g? ( ! mass1 !y may cont9ue to accumulate4 ,^! are n necess>ily connect$ ) /resses t arise f sph]icity1 & may "w m or less indep5d5tly ( !m4 ,x is n improbable t ! great /ress-accumulat+ p[] ( ! globe f9ds an ess5tial "p ( its explanation 9 supplem5tal consid]ations ( ?is k9d1 & n :olly 9 its sph]oidal =m4 ,! actual configuration ( ! surface4--,! =ego+ computations relative to ! p[] ( %ells ( ! e>? to su/a9 pressures are bas$ on ideal =ms & /ructures t are n realiz$ 9 fact4 ,h[ f> ! e>? fails to con=m to ^! conditions mu/ n[ be consid]$4 ,:5 comp>$ ) ! e>? z a :ole1 ! inequalities ( its surface are trivial4 ,if ! great dynamic =ces act$ ?r\gh ! :ole or ! l>g] "p ( ! body ( ! e>?1 ! configuration ( ! surface c be suppos$ to h done little m ?an influ5ce ! location ( ! surface de=mations & _! special phases4 ,b if ! =ces 7 limit$ to a cru/ ( mod]ate ?ickness1 ! configuration ( ! surface is a matt] ( radical importance4 ,concave tracts4--,!re is ne$1 !re=e1 to inquire if any consid]able bread? ( ! cru/ is outw>dly plane or concave1 = ! pr9ciple ( ! dome is obvi\sly n applicable to a plane or concave surface4 ,to be a s\rce ( fatal weakness1 ! concavity mu/ be broad en\gh to cause ! planes ( equal cool+1 ! isogeo!rms1 to be concave to consid]able dep?s4 ,= example1 if ! hypo!tical level ( no /ress is eight miles bel[ ! surface1 z comput$ on c]ta9 assumptions1 ! concave portion mu/ be s broad t ! isogeo!rms w also be concave outw>d at some?+ ne> t dep?2 9 o!r words1 ! ma9 "p ( ! zone ( ?ru/ mu/ be concave4 ,a n>r[ concavity at ! surface1 su* z an ord9>y valley 9 a portion ( ! cru/ t has ! av]age convexity1 w\ld n s]i\sly depress ! isogeo!rms1 or affect ! zone ( ?ru/1 b a valley sev]al times eight miles 7level ( no /ress7 9 bread? w\ld4 ,= inspect+ ! surface ( ! e>? 9 ?is reg>d1 x is conv5i5t to "k :at am\nts ( fall bel[ ! level surface give a true plane = giv5 di/ances4 ,^! are %[n 9 ! foll[+ table3#bgd ---------------------------------------- ----------- ,l5g? ( normal to *ord ,av]age fall ( ,l5g? at middle po9t 9 true plane f ( arc -------------------------- level plane p] 9 mile1 9 feet4 miles4 ,feet4 ,fa?oms4 ,great] fall gives concavity4 ---------------------------------------- ----------- #be #ajj4c #af4g #h4 #ej #dcb4 #gb4 #ag4c #ge #iac4d #aeb4b #bd4c #ajj #a1fhd4 #bhj4g #cc4g #aej #c1gdh4h #fbd4h #di4i #bjj #f1fgd4 #a1aab4c #ff4g #bej #aj1cfi4i #a1gbh4c #hb4i #cjj #ad1idb4 #b1dij4c #ii4f #djj #bf1ffd4 #d1ddd4 #acc4c #ejj #da1fei4 #f1idc4 #aff4f ---------------------------------------- ----------- ,apply+ ^! crit]ia to ! surface ( ! li?osph]e1 x is f\nd t concave tracts f #ajj to #cjj miles 9 bread? are n uncommon4 ,! m notable ( ^! are %[n 9 black on ! accompany+ map1 ,fig4 #ded1 & two typical ones are %[n 9 cross-section 9 ,figs4 #dee & #def4 ,x is to be obs]v$ t concave tracts bord] ! cont95ts v g5]ally4 ,!y are connect$ ) ! desc5t f ! cont95tal %elf to ! abysmal bas9s1 & are unsymmetrical4 ,notable concavities are f\nd 9 "s ( ! great valleys on ! cont95tal plat=ms4 ,! bas9s ( ,lake ,sup]ior1 ,mi*igan1 ,huron1 & ,ont>io are 9 "p concave2 s are ,puget ,s\nd1 ! ,adriatic1 & ! ,dead ,sea2 s also are ! valleys ( ,cali=nia1 ( ! ,po1 & ( ! ,ganges1 :5 ! adjac5t m\nta9s are includ$4 ,"s ( ! 8deeps0 ( ! bottom ( ! ocean are notably concave4 ,fig4 #dee1 a cross-section ( ! ,*all5g] ,deep1 drawn to true scale & convexity1 %[s ! nature ( ! ph5om5on4 ,! bread? is "h #cjj miles1 & ! depression bel[ a true plane is #aa1djj feet4 ,! l[] l9e ( ! figure %[s ! approximate position & =m ( ! normal isogeo!rm ab\t t5 miles bel[ ! surface4 ,assum+ equal conductivity 9 all p>ts1 x is cle> t ! isogeo!rms mu/ be concave upw>ds = a consid]able di/ance bel[ t5 miles4 ,unless ! %ell ( ?ru/ is mu* m ?an t5 miles ?ick1 ^! concave portions %\ld yield z fa/ z cool+ bel[ !m p]mits1 & no /resses aris+ f convexity c\ld be accumulat$4 ,illu/ration3 ,fig4 #ded4--,map ( ! _w1 %[+ 9 black ! *ief subm>9e concavities ( ! li?osph]e4 7,prep>$ by ,w4 ,h4 ,emmons47 ,illu/ration3 ,fig4 #dee4--,section ( ! ,*all5g] ,deep f an isl& on ! ,c>ol9e plateau1 a1 to an isl& on ! ,ladrone plateau1 b1 drawn to a true scale1 %[+ ! real concavity ( ! surface ( ! li?osph]e = a bread? ( #cjj miles4 ,! upp] l9e repres5ts ! sea surface1 a natural level4 ,! next l9e bel[ repres5ts a true plane1 elim9at+ ! curvature ( ! sea surface4 ,! ?ird l9e repres5ts ! bottom ( ! deep4 ,by comp>ison ) ! l9e above1 its true concavity may be se54 ,! l[e/ l9e repres5ts an isogeo!rm at ab\t #aj miles bel[ ! surface2 i4e4 appreciably bel[ 8! level ( no /ress10 z usually comput$1 %[+ t ! :ole ?ru/ zone is concave outw>ds1 if x is limit$ to surface cool+ z usually comput$4 7,prep>$ by ,w4 ,h4 ,emmons47 ,illu/ration3 ,fig4 #def4--,section ?r\gh ! ,atlantic coa/al pla91 ! cont95tal %elf1 & a portion ( ! abysmal bottom1 drawn to a true scale1 %[+ t ! surface ( ! li?osph]e drops bel[ a true plane tang5t to ! cont95tal %elf & ! ocean-bottom4 ,! upp] l9e repres5ts ! surface ( ! coa/al pla9 at ! left & ( ! ocean at ! "r4 ,! l[] l9e repres5ts ! sea-bottom1 & ! middle l9e a true plane tang5t to ! %elf & ! sea-bottom4 ,! bread? ( ! concave tract v>ies f #ajj to #aej miles4 7,prep>$ by ,w4 ,h4 ,emmons47 ,^! concavities ( surface are s ext5sive & s widely di/ribut$ ov] ! globe t no "p ( ! out] %ell c be suppos$ to be capable ( accumulat+ notable /resses unless rigidly atta*$ to ! e>?-body bel[4 ,9 o!r words1 s f> z sph]icity is conc]n$1 ! cru/ mu/ ease all its /resses ne>ly z fa/ z !y accumulate1 if1 z usually assum$1 x re/s on a contract+ or mobile sub/ratum4 ,surface cool+ "u ^! conditions %\ld give only feeble ?ru/s1 develop$ & eas$ ne>ly con/antly4 ,su* movem5ts %\ld be admirably adapt$ to give ^? g5tle1 ne>ly con/ant subsid5ces t furni% ! nice adju/m5ts ( wat]-dep? requir$ = ! accumulation ( ?ick /rata 9 %all[ wat]1 & ^? sl[ upw>d w>p+s t r5ew ! fe$+-gr\nds ( erosion1 ! necess>y complem5t ( ! deposition4 ,^! g5tle1 ne>ly con/ant movem5ts m>k e /age ( geological hi/ory1 & con/itute "o ( its greate/ ?\gh lea/ obtrusive features4 ,b if sup]ficial /resses aris+ 9 ?is way are eas$ 9 produc+ ^! effects1 !y _c accumulate to cause ! great p]iodic movem5ts4 ,ev5 :]e ! cru/ is n concave1 x is s w>p$ & s trav]s$ by folds & fault-planes t its resi/ance to ?ru/ is relatively l[1 & x %\ld1 !re=e1 w>p easily & at _m po9ts1 if ! ?ru/ be conf9$ to a sup]ficial cru/4 ,g5]al conclusion4--,:5 to ! weakness ( ! cru/1 z comput$ "u ideal conditions1 !re is add$ ! weakness inh]5t 9 ^! concave & w>p$ tracts1 ! conclusion seems imp]ative t :ile ! cru/ is ! pliant subject ( m9or & ne>ly con/ant w>p+s1 su* z are ev]y:]e impli$ 9 ! /ratigraphic s]ies1 x is :olly incompet5t to be ! m$ium ( ^? great de=mations :i* occur at long int]vals & m>k (f ! great eras ( geologic hi/ory4 ,^! great de=mations app>5tly involve ! :ole1 or a l>ge "p1 ( ! body ( ! e>?1 & seem to require a v high /ate ( effective rigidity4 ,g5]al ref]5ces on cru/al movem5ts4--,babbage1 ,j\r4 ,geol4 ,soc41 ,vol4 ,,iii 7#ahcd71 p4 #bjf2 ,lyell1 ,pr9ciples ( ,geology1 ,vol4 ,,ii1 p4 #bce2 ,mallet1 ,phil4 ,trans4 7#ahgc71 p4 #bje2 ,reade1 ,orig9 ( ,m\nta9 ,ranges1 & ,evolution ( ,e>? ,/ructure2 ,fi%]1 ,physics ( ! ,e>?'s ,cru/2 ,dutton1 ,great] ,problems ( ,physical ,geology1 ,bull4 ,phil4 ,soc4 ( ,wa%+ton1 ,vol4 ,,xi1 p4 #eb1 also ,am]4 ,j\r4 ( ,sci41 ,vol4 ,,viii 7#ahgd71 p4 #aba1 & ,geology ( ! ,high ,plateaus ( ,utah 7#ahhj72 ,jamieson1 ,qu>4 ,j\r4 ,geol4 ,soc4 7#ahhb71 & ,geol4 ,mag4 7#ahhb71 pp4 #djj & #ebf2 ,heim1 ,me*anismus d] ,gebirgsbildung2 ,m>j]ie & ,heim1 ,les ,dislocations de l'corce t]re/re 7#ahhh72 ,%al]1 ,proc4 ,bo/on ,soc4 ,nat4 ,hi/41 ,vol4 ,,xvii1 p4 #bhh2 ,dana1 ,manual ( ,geol41 #d? ed41 p4 #cde et seq42 ,woodw>d1 ,ma!matical ,!ories ( ! ,e>?1 ,smi?sonian ,rept4 = #ahij1 p4 #aif2 ,willis1 ,! ,me*anics ( ! ,appala*ian ,/ructures1 #ac? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii 7#ahic71 pp4 #baa-bhb2 ,le,conte1 ,!ories ( ,m\nta9 ,orig91 ,j\r4 ,geol4 ,vol4 ,i 7#ahic71 p4 #edb2 ,gilb]t1 ,j\r4 ,geol41 ,vol4 ,,iii 7#ahie71 p4 #ccc1 & ,bull4 ,phil4 ,soc4 ( ,wa%+ton1 ,vol4 ,,xiii 7#ahie71 p4 #ca2 ,van ,hise1 ,e>? ,movem5ts1 ,trans4 ,wis4 ,acad4 ,sci41 ,arts & ,let41 ,vol4 ,,ii 7#ahih71 pp4 #eab-ead2 ,e/imates & ,causes ( ,cru/al ,%ort5+1 ,j\r4 ,geol41 ,vol4 ,,vi 7#ahih71 pp4 #bi-ca2 ,relations ( ,rock ,fl[age to ,m\nta9 ,mak+1 ,mon4 ,,xlvii1 ,u4 ,s4 ,geol4 ,surv4 7#aijd71 pp4 #ibd-ica2 ,a4 ,geikie1 ,text-book ( ,geology1 #d? ed41 pp4 #fgb-gjb4 ,,*apt] ,x4 ,,! ,,extrusive ,,processes4 ,outw>d movem5ts4--,9 ! prec$+ *apt]s movem5ts t[>d ! c5t] h be5 consid]$4 ,! complem5t>y processes ( outw>d movem5t n[ invite att5tion4 ,)\t d\bt ^! are ma9ly b a resultant ( ! c5tripetal actions4 ,= ea* p\nd ( mat]ial mov$ outw>ds an equival5t is q surely mov$ inw>ds4 ,not)/&+ ?is1 ! outw>d movem5ts h a peculi> nature ( _! own1 & s]ve a function ( radical importance 9 ! economy ( ! globe4 ,"s m9or phases h be5 incid5tally consid]$1 su* z ! upw>d fl[ ( spr+s & deep-seat$ wat]s1 b "h ! desc5d+ & asc5d+ factors are alike1 & are closely & obvi\sly connect$4 ,,vulcanism4 ,! great example ( asc5sive action is ! movem5t ( fluid rock f ! int]ior outw>ds4 ,! t]m vulcanism w be us$ to embrace n only volcanic ph5om5a 9 ! n>r[] s5se1 b all outw>d =c+ ( molt5 mat]ial1 :e!r /rictly extrusive or m]ely asc5sive4 ,! philosophy ( ?is asc5sive action1 tak5 z a :ole1 is simple4 ,9 ! ef=t at conc5tration "u ! p[]ful action ( ! e>?'s gravity1 ! mat]ial ( high specific gravity is urg$ m /rongly t[>d ! c5t]1 volume = volume1 ?an t ( less specific gravity1 & z gravity is p]petually active1 x foll[s t :5ev] any movem5t1 molecul> or mol>1 takes place :i* p]mits a readju/m5t ( ! positions ( ! two k9ds ( matt]1 ! heavi] s9ks t[>d ! c5t] & ! light] rises1 or at lea/ t5ds to d s4 ,s also :]e !re are /ress-diff]5ces1 ! mobile matt] t5ds to fl[ f ! regions ( great] /ress t[>d ^? ( less] /ress4 ,9 s f> z any portion ( ! int]ior becomes liquid1 x is free to move up or d[n accord+ to ! balance ( /ress br\ght to be> ^u x1 & adapts itself to any l9e ( lea/ resi/ance available to x4 ,z a natural result1 !re=e1 ! portion ( ! int]ior :i* becomes fluid mo/ l>gely p>ticipates 9 ! outw>d movem5t4 ,9 s f> z molecul> action p]mits a readju/m5t ( mat]ial1 !re is a t5d5cy1 ev5 9 ! solid /ate1 = ! light] mat]ial to move upw>ds & ! heavi] d[nw>ds1 & = ! m /ress$ portions to move t[>d po9ts ( less /ress2 b ?is takes place ) extreme sl[ness4 ,9 s f> z ! mat]ials ( ! int]ior diffuse !mselves ?r\gh ea* o!r1 ! same laws hold good1 b !y are modifi$ by ! special pr9ciples t control diffusion4 ,! outw>d diffusion ( int]ior gases may be a factor ( appreciable importance1 b ?is _c be affirm$ at pres5t4 ,phases ( vulcanism4--,! =c+ ( fluid rock outw>d assumes two g5]al phases1 :i*1 h[ev]1 m]ge into ea* o!r2 & ^! ma9 phases take on v>i\s sub-phases4 ,! fir/ phase embraces ^? outw>d movem5ts ( fluid rock :i* d n rea* ! surface4 ,! lavas1 aft] asc5d+ to ! vic9ity ( ! surface1 intrude !mselves into ! out] =mations ( ! e>? & congeal und]gr\nd 7plutonic74 ,! second phase embraces ^? outw>d movem5ts 9 :i* ! fluid rock rea*es ! surface & gives rise to eruptive ph5om5a 7volcanic74 ,! fir/ is intrusive1 ! second extrusive2 ! fir/ con/itutes irruptions1 ! second eruptions4#bge ,! fundam5tal nature ( ! two is ! same1 b ! extrusions usually take on special phases because ( ! relief ( pressure at ! surface ( ! e>?1 & because ( ! action ( surface-wat]s 9 contact ) ! heat$ lavas4 ,j :]e ! lavas come f1 & h[ !y f9d _! way ?r\gh ! deep-ly+ compact zone bel[ ! zone ( fracture1 may bett] be consid]$ lat]4 ,:5 !y rea* ! zone ( fracture1 !y usually ei!r take advantage ( fissures already =m$1 or =ce passageways = !mselves by fracture4 ,!re is little evid5ce t !y bore _! way ?r\gh ! rocks by melt+1 ?\gh !y appe> to r\nd out _! *annels 9 "s way into pipes1 ducts1 & o!r tubul> =ms :5 !y fl[ ?r\gh !m = long p]iods ( "t4 #a4 ,intrusions4 ,fluid rock =c$ into fissures & solidifi$ !re =ms dikes2 =c$ into *imney-l passages1 x =ms pipes or plugs2 ins9uat$ betwe5 b$s1 x =ms sills2 bun*$ "u /rata s z to ar* !m upw>ds1 x =ms laccoli?s2 mass$ 9 great aggregations und]gr\nd1 x con/itutes ba?oli?s1 z already describ$ 7pp4 #cid & #ejj74 ,lavas sometimes cr[d aside ! adjac5t rocks s f> z to cause !m to take a conc5tric =m ab\t ! intrud$ mass4 ,?is is n uncommon 9 ! olde/ =mations1 & is probably n infrequ5t 9 ! deep] horizons :]e ! pressures are v great4 ,"s "p ( ?is may1 h[ev]1 be due to lat] de=mations4 ,ne>] ! surface1 usually1 ! b$s are m]ely lift$ z 9 =m+ ! sills1 or are b[$ upw>ds1 z 9 ! laccoli?s1 or fault$ z 9 bysmali?s 7p4 #ejj74 ,! heat+ action on ! adjac5t rock v>ies greatly ) ! mass & temp]ature ( ! intrud$ lava4 ,?9 dikes & sills (t5 produce little effect1 :ile great] & hott] masses notably metamorphose ! adjac5t rock4 ,9 "s cases m>k$ effects are due to a ?9 /ream ( lava fl[+ ?r\gh a fissure = a long p]iod1 & s ma9ta9+ a high temp]ature4 ,9 ! lea/ effective cases1 ! adjac5t rock usually %[s "s signs ( bak+4 ,9 ! m>k$ cases1 !re is m or less new cry/allization4 ,! surr\nd+ rock commonly %[s "s evid5ce ( mat]ial d]iv$ f ! lavas2 less (t5 ! lava %[s "s evid5ce ( hav+ receiv$ mat]ial f ! adjac5t rock4 ,b s9ce ! lavas d n usually bore _! way ?r\gh ! /rata 9 ! zone ( fracture1 nor melt ! adjac5t rock1 ! con/itution ( ! lavas is n appreciably *ang$ by ! k9ds ( rock :i* !y p5etrate4 ,on ! o!r h&1 ! intrusions (t5 %[ ! effects ( r rapid cool+ by contact ) ! adjac5t rock1 7a7 by a less co>se cry/allization ne> ! rock-walls1 & sometimes 7b7 9 a segregation ( ! mat]ial4 #b4 ,extrusions4 ,:5 molt5 rock is =c$ to ! surface x gives rise to ! mo/ int5se & impressive ( all geological ph5om5a4 ,! en]gies acquir$ 9 ! int]ior "u great compression "h f9d sudd5 relief4 ,occlud$ gases (t5 exp& ) extreme viol5ce1 hurl+ portions ( ! lavas to great heights & %att]+ !m into fragm5ts con/itut+ 8smoke10 a%1 c9d]s1 bombs1 & o!r pyrocla/ic mat]ial4 ,mu* ( ! explosive viol5ce ( volcanoes has be5 attribut$ to ! contact ( surface-wat]s ) ! hot ris+ lava1 b ! function ( ?is k9d ( action has probably be5 exagg]at$4 ,!re are two phases ( extrusion (t5 q /rongly contra/$4 ,! "o is explosive ejection1 (t5 att5d$ ) great viol5ce2 ! o!r1 a quiet out-well+ ( ! lava1 ) little m ?an ebullition4 ,m or less closely relat$ to ^! diff]5ces are two classes ( conduits1 7a7 ! "o1 great fissures1 out ( :i* ! lava p\rs 9 great volume & spreads =? ov] wide tracts1 (t5 9 broad ?9 %eets2 7b7 ! o!r1 re/rict$ op5+s1 (t5 pipes1 ducts1 or limit$ fissures1 f :i* ! extrusion is usually mu* less abundant1 & h5ce x m l>gely congeals ne> ! orifice1 =m+ cones4 ,fl[s f ! =m] con/itute massive eruptions2 ^? f ! latt]1 ! m famili> volcanic eruptions4 ,!re is no radical diff]5ce betwe5 !m1 & ! two classes bl5d4 ,! ext5t ( ! spread+ ( lava into ?9 %eets is due m to ! mass & ! fluidity ?an to ! =m ( ! outlet4 ,! /up5d\s outfl[s ( c]ta9 geologic p]iods appe> to h issu$ ma9ly f ext5d$ fissures1 d\btless because ^! bett] accommodat$ ! outbur/+ floods4 a4 ,fissure eruptions4--,! *ief kn[n fissure eruptions ( rec5t times are ! va/ basaltic floods ( ,icel&4 ,mo/ ( ! eruptions ( hi/oric times are ( ! volcanic type2 b at c]ta9 times 9 ! pa/ !re 7 prodigi\s outp\r+s1 fl[ foll[+ fl[ until lay]s ?\s&s ( feet ?ick cov]+ ?\s&s ( squ>e miles 7 built up4 ,"o ( ^! occurr$ 9 ,t]ti>y times 9 ,idaho1 ,oregon1 & ,wa%+ton1 :]e "s #bjj1jjj squ>e miles 7 cov]$ ) %eets ( lava1 aggregat+ 9 places #bjjj feet or m 9 ?ickness4 ,e>li] ?an ?is1 9 ,cretace\s times1 !re 7 enorm\s fl[s on ! ,deccan plateau ( ,india1 cov]+ a l area to a dep? ( #djjj to #fjjj feet4 ,/ill e>li] ?an ?is1 9 ,kewe5awan times1 an ev5 m prolong$ succession ( lava-fl[s cov]$ ne>ly all ! area ( ! ,lake ,sup]ior bas91 & ext5d$ beyond x1 & built up a s]ies ( almo/ incr$ible ?ickness1 ! e/imates rea*+ #ae1jjj to #be1jjj feet4 ,9 ^! cases !re is little evid5ce ( explosive or o!r viol5t action4 ,!re are few b$s ( a%1 c9d]s1 & simil> pyrocla/ic mat]ial4 ,! inf]5ce is1 !re=e1 t ! lavas well$ out r quietly & spread !mselves r flu5tly ov] ! surr\nd+ c\ntry4 ,= ! mo/ "p ^! wide-spread+ fl[s are compos$ ( basic mat]ial1 :i* is m easily fusible & m highly flu5t at a giv5 temp]ature ?an ! acidic lavas4 ,! latt] are m dispos$ to =m ?ick embossm5ts ne> ! po9t ( extrusion4 ,massive outfl[s ( ?is class con/itute by f> ! greate/ ph5om5a ( ! extrusive type1 ?\gh !y are n n[ ! dom9ant type4 ,x has be5 sometimes ?\ght t ! m local volcanic type ( extrusion foll[$ ! m massive fissure type z a phase ( decl9e2 b ?is has n be5 sub/antiat$4 ,illu/ration3 ,fig4 #deg4--,lava-fl[ ne> ! ,jordan crat]s1 ,malheur ,co41 ,oregon4 ,?\gh n ( ! gigantic ord]1 x illu/rates ! g5]al aspect ( massive lava-fl[s4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 b4 ,volcanic eruptions4--,9 ! types ( eruption prevail+ at ! pres5t "t1 ! lavas are =c$ out ?r\gh ducts or p]haps %ort fissures or sections ( fissures1 & build up cones ab\t ! v5ts1 ! eruptive action ma9ta9+ crat]s 9 ! c5t]s ( ! cones4 ,! ess5tial feature ( a volcano is ! issuance ( hot rock & gas f a local v5t4 ,a m\nta9 is ! usual result1 b ! m\nta9 is second>y & n usually pres5t 9 ! fir/ /ages2 ! localiz$ eruption is ! prim>y & necess>y factor4 ,! am\nt ( rock matt] eject$ is n necess>ily great4 ,comp>$ to ! massive extrusions ( fissure eruptions1 x is usually r trivial2 b ! volcano makes up 9 demon/rativ5ess :at x lacks 9 massiv5ess ( product4 ,illu/ration3 ,fig4 #deh4--,! volcano ,colima1 ,mexico1 9 eruption4 ,m>* #bd1 #aijc4 7,jos ,m>ia ,arreola1 p] ,fr$]ick ,/>r47 c4 ,int]m$iate ph5om5a4--,on ! bord]-l9e betwe5 ! intrusive & ! extrusive ph5om5a !re are special cases ( int]e/4 ,!re appe> to be c]ta9 in/ances 9 :i* ! intrusion comes s ne> ! surface z to develop explosive ph5om5a )\t ! extrusion ( lava4 ,f ! nature ( ! case ?is is an int]pretation r ?an a demon/ration4 ,x is c]ta91 h[ev]1 t occasional viol5t explosions take place :]e no lava comes 9 sight4 ,?is sometimes occurs 9 old volcanic =mations1 & sometimes 9 regions ( undi/urb$ horizontal /rata4 ,9 ! =m] case ! ph5om5a may be due to ! intrusion ( a fre% tongue ( lava bel[1 or x may be due to ! p5etration ( surface-wat]s to hot rocks t h rema9$ uncool$ f previ\s volcanic action1 & ! developm5t1 by su* contact1 ( a volume ( conf9$ /eam suffici5t to produce ! explosion4 ,a case ( ?is d\btful k9d occurr$ at ,b&ai-,san 9 ,japan 9 #ahhh1 :]e !re 0 a sudd5 & viol5t explosion :i* blew away a consid]able "p ( ! side ( a volcanic m\nta9 :i* _h n be5 9 eruption = at lea/ a ?\s& ye>s4 ,! mass & viol5ce ( ! explod$ mat]ial 0 su* z to fill ! air ) a%es & dbris 9 a fa%ion altoge!r simil> to a typical volcanic eruption4 ,a l>ge tract ( adjac5t c\ntry 0 deva/at$1 & _m lives lo/4 ,! :ole action1 h[ev]1 0 conc5trat$ 9 ! initial explosion1 & )9 a few h\rs ! cl\d ( a%es _h disappe>$ & ! ph5om5on 0 end$4 ,an exam9ation ( ! disrupt$ area reveal$ no signs ( liquid lava4 ,an example ( ! latt] class is ,coon ,butte 9 ,arizona4#bgf ,?is consi/s ( a rim ( fragm5tal mat]ial encircl+ a crat]-l pit f :i* ! fragm5ts 7 obvi\sly =c$ by viol5t explosion4 ,! pit is 9 ord9>y s$im5t>y /rata1 & ! mat]ial ( ! rim is compos$ ( ! disrupt$ fragm5ts ( ! s$im5t>y rock eject$ f ! pit4 ,!re are no signs ( igne\s mat]ial1 b !re 0 igne\s action 9 ! vic9ity4 ,fragm5ts ( a meteorite 7 f\nd on ! rim & 9 ! vic9ity1 b ?is association appe>s to be accid5tal4 ,computation %[s t ! volume ( ! mat]ial ( ! rim closely mat*es ! size ( ! pit4 ,! s\rce ( ! explosion is n demon/rable1 & x may be an error to connect x ) an intrusion ( lava bel[2 b s9ce intrusions rise to v>i\s degrees ( ne>ness to ! surface1 & 9 innum]able cases rea* ! surface1 !re is e reason to ent]ta9 ! conception ( a class ( intrusions :i* develop explosive ph5om5a by close approa* to ! surface1 )\t actually rea*+ x4 ,illu/ration3 ,fig4 #dei4--,photograph ( a portion ( ! moon tak5 at ,lick ,obs]vatory4 ,lun> crat]s4--,!re are gr\nds = ?9k+ t ! rem>kable crat]s ( ! moon1 assum+ t !y are truly volcanic1#bgg may belong to ?is class1 = !y are v simil> to ! ,coon ,butte pit4 ,! capacities ( ! lun> crat]s1 s f> z !y c be e/imat$1 seem to equal1 if !y d n 9 _m cases exce$1 ! volume ( matt] 9 _! rims4 ,!y d n appe> usually to be great cones ( accumulat$ mat]ial ) relatively small crat]s1 l ! typical products ( t]re/rial volcanoes4 ,besides1 !re are no cle> evid5ces ( lava-/reams4 ,! radiat+ tracts once int]pret$ z su* h be5 %[n by increas$ telescopic p[] & ! res\rces ( photography to be at lea/ some?+ o!r ?an lava-/reams4 ,!y are vaguely def9$ tracts :i* run ov] heights & dep?s indiff]5tly1 & are plausibly int]pret$ z l9es ( dbris project$ to extraord9>y di/ances because ( ! abs5ce ( a lun> atmosph]e1 & because ( ! l[ =ce ( ! moon's gravity4 ,s9ce ! moon n[ has no appreciable atmosph]e or surface-wat]s1 & s9ce x is d\btful :e!r x ev] possess$ ei!r on acc\nt ( its probable inability to hold atmosph]ic gases or ! vapor ( wat] 9 ! =m ( an envelope ab\t x1 ow+ to its l[ gravity1 !re is reason to suppose t ! ext]nal matt] ( ! moon d]iv$ f ! explosions ( ! multitude ( lun> volcanoes w\ld rema9 9 a loose1 incoh]5t condition1 f ! abs5ce ( dissolv+ & cem5t+ ag5cies4 ,x is reasonable to suppose t lava-tongues aris+ f ! deep] int]ior w\ld h a high] specific gravity1 ev5 9 _! heat$ condition1 ?an ?is por\s cov]+ ( ! moon1 & t !re=e !y w\ld almo/ univ]sally become intrusions r ?an extrusions1 or at mo/ !y w\ld n rise beyond ! bottom ( ! crat]s !y _h produc$ by explosion4 ,?is seems to furni% at lea/ a plausible explanation ( ! prevail+ diff]5ces betwe5 ! l>ge lun> crat]s encircl$ by m]e rims & ! mu* small] t]re/rial crat]s seat$ 9 relatively l>ge cones4 ,,volcanoes4 ,numb] ( volcanoes4--,x is impracticable to /ate exactly ! numb] ( volcanoes t are active at ! pres5t "t1 because mo/ volcanoes are p]iodic1 & become active at m or less di/ant p]iods1 & x is impossible to say :e!r a giv5 volcano t may be n[ quiesc5t has really become ext9ct or is only enjoy+ its cu/om>y p]iod ( re/4 ,x is q safe to include at lea/ #cjj 9 ! active li/1 & ! numb] may rea* #cej or m4 ,! numb]s t h be5 active s rec5tly t _! cones h n be5 entirely worn away is sev]al times z great4 ,di/ribution ( ,volcanoes4 #a4 ,9 "t4--,9 ! e>lie/ kn[n ages igne\s action appe>s to h be5 v g5]al1 if n practically univ]sal4 ,no area ( ! e>lie/ 7,ar*ean7 rocks is n[ kn[n :i* is n =m$ *iefly ( rocks t appe> to h be5 ei!r intrud$ or extrud$4 ,rocks :i* c reasonably be assign$ to ! hypo!tical molt5 globe1 if !re be su*1 are n "h includ$4 ,x is probable t ! surface ( ! e>ly e>? 0 z ?ickly occupi$ ) po9ts ( extrusion z ! surface ( ! moon appe>s to be4 ,9 ! ages betwe5 ! ,ar*ean & ! pres5t1 ! di/ribution ( volcanic action ov] ! surface seems to h be5 9 a g5]al way mu* :at x is to-day2 t is1 c]ta9 areas 7 volcanically active at times1 :ile o!r & l>g] areas 7 measurably free f any outw>d expressions ( igne\s action4 ,?is is n equally true ( all ages1 z w be se5 9 ! hi/orical /udies t foll[4 ,!re 7 p]iods :5 volcanic activity seems to h be5 widespread & en]getic1 & o!rs :5 x 0 limit$ bo? 9 am\nt & di/ribution4 ,! kn[n facts d n indicate a /eady decl9e 9 volcanic activity1 b r a p]iodicity2 at lea/ ?is is s = ! portion ( ! globe t is n[ well en\gh kn[n geologically to w>rant conclusions4 ,"o ( ! greate/ ( ! volcanic p]iods falls )9 ! ,c5ozoic era1 j prec$+ ! pres5t geological p]iod1 & ! volcanic activity ( ! pres5t is p]haps b a decl9+ phase ( t "t4 #b4 ,relative to l& & sea4--,at pres5t ! active volcanoes are *iefly di/ribut$ ab\t ! bord]s ( ! cont95ts1 &1 less notably1 )9 ! great oceanic bas9s4 ,on ?is acc\nt ! sea has (t5 be5 suppos$ to h "s connection ) volcanic action1 & ! pres5ce ( *lor9e 9 ! volcanic emanations has be5 cit$ 9 support ( ?is position4 ,:5 critically exam9$1 h[ev]1 ! argum5t f di/ribution is n v /rong2 = ! volcanoes are n di/ribut$ equally or proportionately ab\t ! sev]al oceans1 z if dep5d5t on !m4 ,volcanoes are especially num]\s ar\nd & )9 ! ,pacific1 ! greate/ ( ! oceans1 & ?is might seem a favorable in/ance1 b !y are also num]\s ar\nd & )9 ! ,m$it]ranean1 a relatively small body ( wat]4 ,volcanoes are n especially abundant 9 or ab\t ! m>g9s ( ! ,atlantic4 ,illu/ration3 ,fig4 #dfj4--,volcanoes 9 ! ,pacific4 ,jones ,relief ,globe4 7,photo4 by ,r4 ,t4 ,*amb]l947 ,if volcanoes 7 dep5d5t ^u proximity to ! sea1 ! relation %\ld be close 9 ! pa/ z well z 9 ! pres5t1 b ?is does n seem to be true4 ,!re has rec5tly be5 mu* volcanic activity 9 ! plateau region ( we/]n ,am]ica at long di/ances f ! ,pacific bas94 ,ev5 on ! pla9s ea/ ( ! ,rocky ,m\nta9s notable volcanic action took place4 ,!re 7 also volcanoes 9 ! int]ior ( ,asia & ( ,africa4 #c4 ,relative to cru/al de=mations4--,! di/ribution ( pres5t & rec5t volcanoes is mu* m sugge/ively associat$ ) ^? portions ( ! cru/ t h und]gone notable *anges 9 position 9 comp>atively rec5t times4 ,! great 8_w-ridge0 /ret*+ f ,cape ,horn to ,alaska & !nce onw>ds along ! ea/ coa/ ( ,asia is a /rik+ in/ance1 = x is dott$ ?r\gh\t ) active & rec5tly ext9ct volcanoes4 ,! tortu\s zone ( m\nta9\s wr9kles t bord]s ! ,m$it]ranean & /ret*es !nce ea/w>d to ! ,polynesian ,isl&s is ano!r notable volcanic tract4 ,^! two belts include ! great] numb] ( exi/+ & rec5t volcanoes on ! l&1 :ile ! great bas9s associat$ ) !m embrace ! *ief oceanic volcanoes4 ,illu/ration3 ,fig4 #dfa4--;,active volcanic area at ! junction ( ! cont95tal segm5ts ( ,nor? & ,s\? ,am]ica1 & ( ! abysmal segm5ts ( ! ,atlantic & ,pacific4 ,jones ,relief ,globe4 7,photo4 by ,r4 ,t4 ,*amb]l947 ,!re is p]haps "s significance 9 ! fact t ! mo/ active regions ( vulcanism to-day lie at ! angul> junctions ( ! great e>?-segm5ts4 ,! ,antillean & ,c5tral ,am]ican volcanic region1 t has rec5tly be5 s demon/rative1 lies :]e ! s\!rn angle ( ! ,nor? ,am]ican cont95tal block jo9s ! nor!rn angle ( ! ,s\? ,am]ican cont95tal block1 & :]e ! we/]n angle ( ! ,nor? ,atlantic abysmal segm5t closely approa*es "o ( ! ea/]n angles ( ! great ,pacific abysmal segm5t4 ,! complex & v active ,java-,philipp9e volcanic region lies :]e ! s\!a/]n angle ( ! great ,asian segm5t projects t[>d ! ,au/ralian block1 & :]e ! we/]n angle ( ! ,pacific block approa*es ! nor!a/]n angle ( ! ,indian oceanic segm5t4 ,! active ,alaskan volcanic area lies at ! angles ( ! ,nor? ,am]ican1 ,asian1 ,pacific1 & ,arctic segm5ts4 ,! ,m$it]ranean volcanic area falls less notably "u ?is g5]alization1 b x lies :]e ! cont95tal blocks ( ,europe & ,africa come into peculi> relations to ea* o!r on ei!r side ( ! rem>kable ,m$it]ranean tr\gh4 ,! ea/]n angle ( ! ,nor? ,atlantic segm5t is ne> by1 b n 9 v close relations4 ,! ,icel&ic region1 small b vigor\s1 lies ne> ! junction ( ! ,nor? ,am]ican1 ,european1 ,nor? ,atlantic1 & ,arctic segm5ts1 & ! ,new ,zeal& volcanic region is some:at less closely relat$ to ! approa* ( ! ,au/ralian1 ,ant>ctic1 ,pacific1 & ,s\!rn oceanic segm5ts4 ,ne>ly all ( ^! angul> conjunctions involve two depress$ segm5ts jo9+ two relatively elevat$ segm5ts4 ,?is relation%ip sugge/s a causal connection betwe5 ! int5sifi$ movem5ts at ^! angul> conjunctions & ! int5sifi$ volcanic action ( ^! regions4 ,!re are en\gh volcanoes1 h[ev]1 t d n fall into ^! gr\ps1 or app>5tly into any o!r gr\p+1 to sugge/ t ! developm5t ( volcanoes is n :olly dep5d5t on any surface relation%ip1 b t x is connect$ ) deep-seat$ causes t are inde$ modifi$1 b n :olly controll$1 by surface conditions1 or ev5 by ! movem5ts ( ! ma/] segm5ts ( ! e>?'s cru/4 ,illu/ration3 ,fig4 #dfb4--;,active volcanic area at ! junction ( ! cont95tal segm5ts ( ,asia & ,au/ralia1 & ! abysmal segm5ts ( ! ,pacific & ,indian oceans4 ,jones ,relief ,globe4 7,photo4 by ,r4 ,t4 ,*amb]l947 #d4 ,9 latitude4--,! di/ribution ( volcanoes appe>s to h no specific relation to latitude4 ,m\nts ,erebus & ,t]ror1 amid ! ice-mantle ( ,ant>ctica1 & ,m\nt ,hecla 9 ,icel&1 z well z ! num]\s volcanoes ( ! ,aleutian *a91 give no gr\nd = suppos+ t volcanoes %un ! frigid zones4 ,on ! o!r h&1 ! num]\s volcanoes ( ! equatorial zone d n imply t !y avoid ! torrid belt4 ,_! di/ribution appe>s to be indep5d5t ( latitude4 ,?is is n cit$ because ( any suppos$ effects ( ext]nal temp]ature1 = t mu/ be trivial1 b because x be>s on ! "q :e!r /ra9s are n[ aris+ f ! suppos$ slack5+ ( ! e>?'s rotation1 :i* h any connection ) volcanic action4 ,if ! oblat5ess ( ! e>? is decreas+1 ! equatorial belt mu/ be s9k+ & gr[+ %ort]1 & h5ce mu/ be "u lat]al pressure1 :ile ! pol> caps mu/ be ris+1 & increas+ _! curvatures1 & %\ld be "u t5sion4 ,^! conditions1 if real1 might be suppos$ to h some?+ to d ) ! extrusion ( lava4 ,no?+ 9 ! pres5t or ! pa/ di/ribution ( igne\s action seems to af=d mu* support to ?is hypo!tical inf]5ce4 #e4 ,9 curv$ l9es4--,9 ! ,antilles1 ! ,aleutian ,isl&s1 ! ,kurile ,isl&s1 & 9 o!r in/ances1 !re is a notable l9e> arrangem5t ( volcanoes ) appreciable curvature4 ,x has be5 not$ t ! convexity ( ! curves is turn$ t[>d ! adjac5t ocean4 ,9 "s cases1 h[ev]1 !re is a notable l9e> arrangem5t )\t appreciable curvature1 z 9 ! ,hawaiian range1 9 ! rec5tly ext9ct l9e ( cones ( ! ,cascade ,range1 & 9 o!rs4 ,less (t51 volcanoes are bun*$ irregul>ly1 z 9 "s ( ! gr\ps ( volcanic isl&s ( ! ,pacific 7,fig4 #dfj74 ,relations ( ,volcanoes4 #a4 ,relations to ris+ & s9k+ surfaces4--,s f> z obs]vations cov] ?is po9t1 ! area imm$iately adjac5t to active volcanoes is ris+ 7,dutton74 ,?is is %[n by rais$ bea*es1 t]races1 coral deposits1 etc4 ,:e!r ?is is :olly due to ! expansional effect ( ! heat+ ( ! subt]rane by ! ris+ lava1 or :e!r x has a wid] significance1 is n kn[n4 ,if a broad] view is tak51 x does n appe> t !re are suffici5t data to connect volcanic action exclusively ) ei!r ! ris+ or ! s9k+ ( ! g5]al surface4 ,x is c]ta9 t ! great m\nta9 ranges & plateaus 9 :i* s mu* ( ! m rec5t volcanic action has tak5 place h be5 rec5tly elevat$ relatively1 b !y h also und]gone m or less ( oscillation1 involv+ "s relative depression4 ,! "q :e!r ! ,pacific bas9 z a :ole has be5 relatively elevat$ or depress$ 9 mod]n times is a moot$ "o4 ,d>w9#bgh & ,dana1#bgi z ! result ( _! e>ly /udies on its coral deposits & on o!r ph5om5a1 conclud$ t ! ,pacific 0 a s9k+ area1 b ?is view has be5 rec5tly *all5g$ by ,murray#bhj & ,agassiz#bha ) at lea/ "s measure ( success4 ,f ! fiords on ! bord]s ( ! ,pacific & o!r physical ph5om5a1 ! inf]5ce has be5 drawn t relative s9k+ ( ! l& has rec5tly tak5 place4 ,rais$ bea*es on ! coa/s are int]pret$ z indicat+ a relative rise ( ! l& or a s9k+ ( "s ocean bas91 = ! )drawal ( ! wat]s c only be ! result ( increas+ ! capacity ( ! oceanic bas9 z a :ole4 ,! mo/ probable view is t ! g5]al areas ( pres5t & rec5t volcanic action are p>tly ris+ areas & p>tly s9k+ areas1 & t movem5t ( ei!r k9d may be connect$ ) ! extrusion ( ! lavas4 ,! ris+ & s9k+ are b complem5t>y phases ( a de=mation ( ! e>?'s body1 & involve a readju/m5t ( /resses )9 ! body ( ! e>?4 ,^! /resses are possibly an ess5tial factor 9 eruptions4 #b4 ,relations to "o ano!r4--,a mo/ significant feature ( volcanic action is ! degree ( concurr5ce or ( indep5d5ce ( action 9 adjac5t volcanoes4 ,9 "s in/ances !y act z ?\gh 9 sympa?y1 z 9 ! rec5t outbur/ 9 ,m>t9ique & ,sa9t ,v9c5t1 & ! concurr5t symptoms ( activity 9 o!r places4 ,on ! o!r h&1 ! indep5d5ce ( neighbor+ v5ts is sometimes extraord9>y4 ,! gr\p ( volcanoes ne> ! c5t] ( ! ,m$it]ranean1 ( :i* ,vesuvius & ,etna are ! mo/ conspicu\s examples1 usually act ) measurable indep5d5ce ( "o ano!r1 an eruption 9 ! "o n be+ habitually co9cid5t ) an eruption 9 ! o!rs4 ,b ! mo/ conspicu\s in/ance ( indep5d5ce is f\nd 9 ! great crat]s ( ,mauna ,loa & ,kilauea 9 ,hawaii4 ,!y are only ab\t tw5ty miles ap>t1 ! "o on ! top & ! o!r on ! side ( ! same great m\nta9 mass4 ,! crat] ( ,mauna ,loa is ab\t #aj1jjj feet high] ?an ! crat] ( ,kilauea1 & yet1 :ile ! latt] has be5 9 con/ant activity z f> back z its hi/ory is kn[n1 ! =m] is p]iodic4 ,! case is ! m rem>kable because ( ! greatness ( ! ejections4 ,! outfl[ ( ,mauna ,loa 9 #ahhe =m$ a /ream f ?ree to t5 miles 9 wid?1 & =ty-five miles 9 l5g?1 ) a probable av]age ?ickness ( #ajj feet1 & "s ( its o!r outfl[s 7 ( ne>ly equal greatness2 inde$ its outfl[s are among ! mo/ massive t h issu$ f volcanoes 9 rec5t times4 ,besides ?is massiv5ess !re h be5 extraord9>y movem5ts ( ! lava )9 ! crat]1 if ! te/imony ( witnesses may be tru/$4 ,b ?r\gh\t ^! great movem5ts 9 ! high] crat]1 ! lava-column ( ,kilauea1 #aj1jjj feet l[]1 cont9u$ its quiet action )\t s5sible effects f its boi/]\s neighbor4 ,! be>+ ( su* extraord9>y indep5d5ce ^u ! s\rces ( volcanic action is v cog5t1 = ! lavas are ( ! same type1 bo? be+ basalts1 t ( ,mauna ,loa be+ notably basic & probably z high 9 specific gravity z t 9 ,kilauea4 ,no diff]5ce 9 specific gravity t c\ld at all acc\nt = a diff]5ce 9 height ( #aj1jjj feet c be presum$1 unless _! ducts rema9 sep>ate to extraord9>y dep?s4 ,nor does x appe> possible t a sup]ior am\nt ( gas )9 ! column ( ,mauna ,loa c\ld acc\nt = su* an extraord9>y diff]5ce 9 height1 = ! hydro/atic pressure ( su* a column is n f> f #aj1jjj p\nds to ! squ>e in*4 ,ev5 if ! diff]5ce 9 ! heights ( ! columns c\ld be expla9$ by diff]5ces 9 specific gravity1 ! agitation ( ! "o %\ld be communicat$ to ! o!r1 & an outfl[ ( ! "o1 p>ticul>ly an outfl[ by a breakage ?r\gh its walls suffici5t to l[] its surface hundr$s ( feet1 z has repeat$ly occurr$ 9 ,kilauea1 %\ld *ange ! surface ( ! o!r proportionately1 if !y 7 9 hydro/atic equilibrium4 ,x seems a necess>y inf]5ce1 !re=e1 t ! two lava-columns h no connection ) ea* o!r or ) a common res]voir4 ,! tops ( "s lava-columns /& ab\t #bj1jjj feet above ! sea1 :ile o!rs em]ge on ! sea-bottom f> bel[ sea-level4 ,! total v]tical range is1 !re=e1 probably betwe5 #cj1jjj & #dj1jjj feet1 a diff]5ce :i* tells its own /ory z to _! relative indep5d5ce4 ,illu/ration3 ,fig4 #dfc4--,surface ( lava-fl[ ( #ahha1 f ,mauna ,loa1 z se5 back ( ,hilo1 ,hawaii4 7,photo4 by ,calv947 #c4 ,unimportant co9cid5ces4--,eruptions seem to be some:at m liable to occur at times ( high atmosph]ic pressure ?an at l[1 d\btless because ! increas$ atmosph]ic weight on a l>ge area ( ! adjac5t cru/ aids 9 =c+ out ! lava or ! volcanic gases4 ,?is c only be effective :5 o!r =ces h almo/ accompli%$ ! result1 & w\ld d\btless h complet$ x a little lat] _h n ! atmosph]ic wave suppli$ ! little rema9+ pressure ne$$4 ,eruption seems also to be m common :5 ! tidal /ra9s favor x1 = l reasons4 ,9 ! same class are probably to be put ! effects ( heavy ra9s1 :e!r !y act by gravity or by giv+ rise to /eam4 ,su* ag5cies are to be reg>d$ z m]e incid5ts ( no mom5t 9 ! real causation ( vulcanism1 b ( "s value 9 det]m9+ ! precise mom5t ( action4 ,?is is n to be und]/ood z inconsi/5t ) ! view t ! p]iodic /resses ( ! body-tides ( ! e>? are important factors 9 vulcanism1 z else:]e expla9$1 b m]ely t ! special "t ( surface-eruption is only incid5tally connect$ ) ! wat]-tides4 ,illu/ration3 ,fig4 #dfd4--;,crat] ( ,kilauea4 ,p]iodicity4--,mo/ volcanoes are p]iodic 9 _! /ages ( action4 ,long dormant p]iods int]v5e betwe5 eruptive p]iods4 ,volcanoes suppos$ to be ext9ct occasionally awak5 ) t]rific viol5ce4 ,sometimes also !y awak5 quietly4 ,?is l>g] p]iodicity yet awaits an explanation1 b x v likely means a tempor>y exhau/ion ( ! supply ( gas or ( lava1 or ( bo?1 to :i* ! active /age is due4 ,=mation ( ,cones4 ,lava-cones4--,! lava usually fl[s away f ! v5t 9 %ort /reams :i* solidify be=e runn+ f>4 ,z ! lava-/reams fl[ 9 diff]5t directions at diff]5t times1 ! total effect is a l[ cone =m$ ( radiat+ tongues surr\nd+ ! po9t ( exit4 ,occasionally ! /reams run a doz5 or a score ( miles1 b su* cases1 except 9 ! gigantic volcanoes ( ,hawaii & a few o!rs1 are r>e4 ,(t5 ! /reams congeal be=e !y rea* mu* beyond ! base ( ! cone1 & q (t5 :ile !y are yet on its slope4 ,s f>1 !re=e1 z ! volcanic cone is =m$ ( lava1 x has a radiate /ructure made up ( a succession ( congeal$ lava-/reams4 ,9 ^! cases ! slopes are l[1 because ! fluidity ( ! lava prev5ts ! developm5t ( high gradi5ts4 ,x is1 h[ev]1 r ! exception ?an ! rule1 t ! cone is made up ma9ly ( lava-/reams1 ?\gh ! great ,hawaiian volcanoes are ( ?is class4 ,illu/ration3 ,fig4 #dfe4--,typical c9d]-cone1 ,clayton valley1 ,cal4 7,turn]1 ,u4 ,s4 ,geol4 ,surv47 ,c9d]-cones4--,! l>g] portion ( ! lava bl[n into ! air by ! exp&+ gas-bubbles falls back 9 ! imm$iate vic9ity ( ! v5t & builds up a c9d]-cone4 ,f ! nature ( ! case1 ?is (t5 takes on a beautiful symmetry & assumes a /eep slope 7,fig4 #dfe74 ,! ragg$ c9d]s l5d !mselves readily to ! =mation ( an acute cone1 q diff]5t f ! flatt] cone =m$ by lavas4 ,sometimes ! c9d]s are /ill pla/ic :5 !y fall1 & weld !mselves toge!r & hold _! places ev5 on v /eep slopes1 b usually !y h already h>d5$ be=e !y rea* ! surface4 ,illu/ration3 ,fig4 #dff4--,spatt]-cone & cav]n4 ,kilauea1 ,hawaii4 7,photo4 by ,libbey47 ,illu/ration3 ,fig4 #dfg4--;,holl[ spatt]-cone4 ,oregon4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,subord9ate cones4--,small or tempor>y v5ts =m$ z (f%oots f ! ma9 v5ts (t5 give rise to second>y or 8p>asitic0 cones4 ,^! are sometimes num]\s1 z 9 ! case ( ,etna1 & !y may be s important t ! m\nta9 becomes a comp\nd cone4 ,a /ill m subord9ate v>iety consi/s ( 8spatt]-cones0 =m$ by small mildly explosive v5ts t spatt] =? little dabs ( lava :i* =m *imneys1 or cones1 & sometimes completely curv$ domes ov] v5ts 7,figs4 #dff & #dfg74 ,spatt]-cones (t5 arise f ! lava-fl[s !mselves4 ,composite cones4--,f mo/ exi/+ volcanoes !re issue bo? lava-fl[s & fragm5tal ejecta1 & ! result+ cones are composite 9 mat]ial4 ,! lava m frequ5tly breaks ?r\gh ! side ( ! cone ?an ov]fl[s its summit1 & ?is gives rise to irregul>ities ( =m & /ructure4 ,! cones are also subject to p>tial de/ruction bo? by ! outbur/s ( lava & by ! explosions1 & p]haps also by migration ( ! v5ts4 ,z a result1 _m volcanic regions %[ old1 p>tially de/roy$ crat]s1 toge!r ) new & m p]fect ones1 & ! hi/ory ( volcanic action 9 a region may (t5 be read 9 ! succession ( cone =mations4 ,! =m ( ! cone1 :5 compos$ *iefly ( lava1 is also affect$ by ! mass ( ! outfl[ & by its fluidity4 ,! l>g] ! outfl[ at a giv5 "t1 o!r ?+s be+ equal1 ! wid] x di/ributes itself & ! flatt] is ! cone4 ,z a rule1 ! basic lavas are m fluid ?an ! acidic1 & ! cones ( basic lavas are flatt] ?an ! cones ( acidic lavas4 ,extra-cone di/ribution4--,9 viol5t eruptions1 ! /eam1 accompani$ ) mu* a%1 is %ot up to great heights1 (t5 roll+ outw>ds 9 cumulus or caulifl[]-l =ms 7,fig4 #deh74 ,9 ! m viol5t explosions ^! columns are project$ sev]al miles4 ,9 ! ph5om5al case ( ,krakatoa ! projection 0 e/imat$ at sev5te5 miles4 ,! /eam1 by reason ( its great expansion & its contact ) ! cold] regions ( ! upp] air1 is quickly cond5s$1 & prodigi\s floods ( ra9 frequ5tly accompany ! eruption4 ,?is ra91 c>ry+ d[n a portion ( ! a% & ga!r+ up mu* t _h previ\sly fall51 gives rise to mud-fl[s1 :i* 9 "s cases con/itute a l>ge "p ( ! f9al deposit4 ,^! mud-fl[s *iefly lodge on ! l[] slopes ( ! volcano or adjac5t to its base1 & give rise to r flat cones1 sometimes designat$ z tufa-cones to di/+ui% !m f c9d]-cones =m$ by ! direct fall ( fragm5tal mat]ial4 ,mud-fl[s appe> also to be =m$ by ! ejection ( mud & wat] t _h ga!r$ 9 quiesc5t crat]s dur+ int]vals betwe5 /ages ( eruption4 ,a portion ( ! f9] explod$ mat]ial floats away 9 ! air to great] or less di/ances1 & =ms widespread tufa-deposits4 ,94 "s cases b$s ( volcanic a% ( appreciable ?ickness 7z ^? ( ,nebraska7#bhb are f\nd f> f any kn[n volcanic c5t]4 ,! extremely f9e a% f ! great explosion ( ,krakatoa float$ sev]al times ar\nd ! e>? 9 ! equatorial belt & spread nor?w>d into ! temp]ate zones4 ,illu/ration3 ,fig4 #dfh4--,mt4 ,%a/a1 a typical ext9ct cone1 furr[$ by erosion1 b reta9+ its g5]al =m4 7,dill]1 ,u4 ,s4 ,geol4 ,surv47 ,,lavas4 ,_! nature4--,9 ! *apt] on ! ,orig9 & ,desc5t ( ,rocks1 ! nature ( lavas & ( ! rocks d]iv$ f !m has be5 discuss$ 7,*apt] ,,vii74 ,9 view ( preval5t misconceptions1 x may be repeat$1 = ! sake ( emphasis1 t lavas are mutual solutions ( m9]al matt] 9 m9]al matt]1 r ?an simply melt$ rock4 ,into ?is mutual solution !re ent] n only rock mat]ials1 b gases4 ,! di/9ction betwe5 mutual solutions & simple molt5 rock _c be rigor\sly made1 b x is at lea/ ess5tial to "k t ! m9]als d n necess>ily cry/allize f lavas 9 ! ord] ( _! melt+ temp]atures1 or 9 any uni=m ord]1 b r 9 ! ord] 9 :i* saturation ( ! sev]al m9]al con/itu5ts happ5s to be rea*$ 9 ! giv5 mutual solution4 ,?us qu>tz1 :i* has a v high melt+-po9t1 is (t5 "o ( ! la/ m9]als to cry/allize4 ,! mutual solutions are exce$+ly complex1 embrac+ a wide range ( *emical sub/ances1 b ! *ief ( !m1 z already /at$1 are silicates ( alum9um1 potassium1 sodium1 calcium1 magnesium1 & iron1 ) m9or +r$i5ts ( ne>ly all kn[n sub/ances1 9 great] or less proportion4 ,! old idea ( lavas z simply melt$ rock is n1 h[ev]1 :olly to be ab&on$4 ,! mode ( solidify+ is (t5 simply t ( molt5 matt] freez+4 ,if lava be sudd5ly cool$1 ! congelation is ess5tially ! solidification ( a melt$ sub/ance4 ,! result is a glassy body1 e "p ( :i* has ess5tially ! same composition t ! liquid _h4 ,usually1 h[ev]1 ev5 9 ?is case1 ! gases escape 9 "p4 ,if ! cool+ is sl[]1 ! v>i\s sub/ances 9 ! mixture cry/allize out into m9]als 9 ! ord] 9 :i* !y sev]ally rea* saturation4 ,?is involves ! pr9ciple t solubility is dep5d5t on temp]ature1 & t z ! temp]ature s9ks ! degree ( solubility decl9es1 & ! saturation-po9t = "s con/itu5ts ( ! solution is rea*$ e>li] ?an = o!rs4 ,) suffici5tly sl[ cool+1 all ! mat]ial w pass into ! solid /ate by ! cry/alliz+ ( ! sev]al m9]als 9 succession4 ,?is does n mean t two or m m9]als may n be =m+ at ! same "t1 = cry/als (t5 int]f]e ) ea* o!r's gr[?4 ,x does1 h[ev]1 involve ! doctr9e t "s sub/ances may complete _! cry/allization :ile ! surr\nd+ mat]ial is yet 9 ! fluid condition4 ,9 mo/ igne\s rocks ne>ly p]fect cry/als ( c]ta9 m9]als are common1 :ile o!r m9]als1 cry/alliz+ lat]1 are compell$ to adapt !mselves to ! space left4 ,?is conception is support$ by ! fact t lavas1 :ile /ill 9 ! fluid condition1 (t5 conta9 well-=m$ cry/als1 & ^! cry/als sometimes make up a consid]able p]c5t4 ( ! fl[+ mass1 j z wat] 9 c]ta9 conditions may be fill$ ) cry/als ( ice4 ,s also cry/als aft] hav+ be5 =m$ may be r$issolv$ 9 "p1 d\btless because ( *anges 9 ! nature ( ! magma due to undet]m9$ conditions :i* may arise 9 ! process ( cry/allization1 or f ! accession ( gas1 or f new mat]ial dissolv$ f ! walls ( ! passageway4 ,illu/ration3 ,fig4 #dfi4--,lobul> =m ( lava-fl[1 8,pahoehoe40 7,dutton1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dgj4--,t]m9al portion ( a r\gh lava-fl[1 8aa40 ,c9d] ,buttes1 ,idaho4 7,russell1 ,u4 ,s4 ,geol4 ,surv47 ,illu/ration3 ,fig4 #dga4--,lava fl[+ ov] a precipice ne> ,hilo1 ,hawaiian ,isl&s4 ,consangu9ity & succession ( lavas4--,! lavas t are p\r$ =? at diff]5t /ages 9 ! succession ( eruptions ( a giv5 region are usually n ! same1 z might naturally be expect$1 b =m a curi\s s]ies ! memb]s ( :i* are relat$ to "o ano!r4 ,idd+s has call$ ?is relation consangu9ity4#bhc ,no univ]sal law ( succession has yet be5 e/abli%$1 & p]haps none exi/s2 b ,ri*?(5#bhd _m ye>s ago ann\nc$ a def9ite ord] = ! ,t]ti>y fl[s ( we/]n ,am]ica :i* seems to hold fairly well 9 its g5]al aspects1 ?\gh n ev]y:]e completely realiz$1 s f> z surface obs]vation goes4 ,ri*?(5's ord] is3 7#a7 lavas ( neutral types1 7#b7 lavas ( acid types1 7#c7 lavas ( basic types1 7#d7 lavas ( m acid types1 & 7#e7 lavas ( m basic types4 ,! special v>ieties ( rock v>y1 & ev5 ! g5]al ord] is (t5 app>5tly defective4 ,! defects are sometimes assign$ to ! concealm5t ( "s ( ! outfl[s4 ,:ile ?is may be true 9 "s cases1 x is n unlikely t 9 o!rs !re is a real failure ( ! sequ5ce4 ,at any rate1 ! sequ5ce c only be reg>d$ z a r\gh g5]alization4 ,x is suppos$ to be due to magmatic diff]5tiation caus$ by ! diff]5ces ( temp]ature to :i* ! diff]5t p>ts are subject$ und]gr\nd1 by diff]5ces ( specific gravity & fluidity :i* result f *anges ( temp]ature1 & probably by o!r causes4 ,temp]atures ( lavas4--,accurate det]m9ations ( ! temp]atures 9 ! c5t] ( ! lava-columns1 :]e !y h be5 lea/ r$uc$ by contact ) ! rock-walls1 h n yet be5 made1 b x is cle> f ! :it5ess ( ! lavas t _! temp]atures are (t5 appreciably above ! melt+-po9t4 ,?is is also a necess>y inf]5ce f ! l5g? ( "t !y rema9 fluid1 not)/&+ ! great surface contact ( ! column 9 its miles ( asc5t1 ! conv]sion ( contact wat] into /eam1 & ! expansion & escape ( ! gases4 ,9 cases :]e det]m9ation has be5 practicable 7& !y c]ta9ly d n repres5t ! maximum temp]atures7 x has be5 f\nd t ! melt+-po9ts ( silv]1 ab\t #ifj ,c41 & ( copp]1 ab\t #ajfj ,c41 are rea*$4 ,9 connection ) ov]fl[s1 x has be5 f\nd t brass is decompos$ into its compon5t metals1 ! copp] actually cry/alliz+4 ,silv] has be5 sublim$1 & made to r$eposit itself 9 cry/all9e =m4 ,?is implies mu* m ?an ! b>e melt+ temp]atures4 ,ev5 ! f9e edges ( fl9ts h be5 fus$4 ,x is1 !re=e1 probably safe to assume t ! orig9al temp]atures ( ! lavas z !y rise to ! surface sometimes rea* consid]ably beyond #bjjj ,fahr4 7#ajic ,c471 & may p]haps ev5 atta9 #cjjj ,fahr4 or m4 ,ev5 ^! temp]atures mu/ be some:at bel[ ! orig9al subt]ranean temp]atures ( ! lavas1 because "s heat mu/ necess>ily be lo/ 9 ris+1 p>tly by contact ) ! walls ( ! cold] rocks ?r\gh :i* !y pass1 probably = z mu* z a score ( miles at lea/1 & p>tly f ! expansion ( ! gases )9 !m4 ,if any consid]able "p ( ^! gases is d]iv$ f wat]s :i* jo9$ ! lava 9 its upw>d c\rse 9 ! fracture zone1 ! en]gy consum$ 9 rais+ ! wat] to ! high temp]atures ( ! lavas mu/ be subtract$ f ! orig9al heat1 & mu/ be a fur!r s\rce ( r$uction ( temp]ature4 ,x is important to emphasize ?is po9t 9 view ( its be>+ ^u ! orig9 ( ! lavas4 ,x has be5 sugge/$ t lavas may be due to an aqueo-igne\s fusion1 a k9d ( fusion :i* may take place at comp>atively mod]ate temp]atures4 ,x seems obvi\s1 h[ev]1 f ! ph5om5a !mselves1 t temp]atures z high z ord9>y dry fusion1 & p]haps ev5 high]1 are atta9$4 ,x is cle> also t ! ma9t5ance ( ! liquid condition 9 a con/ant /ate ( ebullition = a long p]iod ( "t implies a l>ge surplus ( heat above t necess>y = liquefaction simply4 ,?is is especially true if ! ebullition comes f surface-wat]s p5etrat+ to & becom+ absorb$ 9 ! lava-column bel[4 ,?is process mu/ t5d rapidly to exhau/ ! heat 9 ! column ( lava4 ,if1 on ! o!r h&1 ! gases are d]iv$ f ! deep int]ior1 & ! ebullition at ! surface is due to _! escape1 !y may br+ up new supplies ( heat to c\nt]act ! cool+ effects ( _! expansion4 ,dep? ( s\rce4--,attempts h be5 made to asc]ta9 ! dep? f :i* lavas rise1 by means ( ! e>?quake tremors t accompany eruptions4 ,! e/imates h rang$ f sev5 or eight to ?irty miles4 ,! mode ( e/imate is t discuss$ "u e>?quakes1 & is subject to ! corrections !re indicat$4 ,if ^! c\ld be p]fectly appli$1 ! e/imates might probably all fall )9 t5 miles1 & n improbably all )9 six miles ( ! surface4 ,b 9 any case ! me?od really tells v little z to ! true po9t ( orig9 ( ! lava4 ,at mo/ x probably only tells :]e ! asc5d+ lava beg9s to rupture ! rock ?r\gh :i* x passes1 & rupture may n be possible bel[ ! zone ( fracture1 :i* is probably n m ?an six miles deep4 ,9 ! zone ( fl[age bel[1 :]e ! pressure is too great to p]mit fracture1 ! lava n improbably makes its way by "s bor+ or flux+ process1 :i* might n1 because ( its nature1 be capable ( giv+ rise to seismic tremors4 ,! behavior ( ! tremors p]haps =ces u to locate ! orig9 ( lava movem5t at lea/ z l[ z ! bottom ( ! fracture zone1 b x probably (f]s no suffici5t gr\nd = limit+ ! lava's orig9 to ?is or any o!r specific dep?4 ,,volcanic ,,gases4 ,! mo/ di/9ctive feature ( volcanoes is ! explosive action aris+ f ! gases & vapors p5t up 9 ! lava4 ,!re is n a little explosive action ( a second>y "* aris+ f ! m]e out] contact ( surface-wat]s ) lavas or ) ! hot rocks ( ! crat] walls1 or ) ! hot a%es & rocks ?r[n out2 b ^! are incid5tal1 n ess5tial1 features4 ,! precise nature ( ! occlusion or absorption ( gases & vapors has n yet be5 det]m9$4 ,x is ?\ght t lava spontane\sly absorbs su* gases :5 at high temp]atures1 & especially :5 ! gases are "u great pressure1 & t z ! pressure is reliev$ & ! lava is cool$ & solidifi$1 ! l>g] "p ( ! gases escapes4 ,9 ^? cases 9 :i* ! eruption is quiet1 ! escape ( ! gases is b p>tial :ile ! lava is 9 ! crat]1 & mu* gas rema9s to be giv5 out f ! molt5 mat]ial aft] x has be5 extrud$ & is ab\t to congeal4 ,! gases are !n giv5 (f ) relative sl[ness & quietness4 ,if1 h[ev]1 ! lavas are sur*>g$ ) gases1 & if ^! are re/ra9$ f free escape by ! viscosity ( ! lavas1 ! gases ga!r 9 l>ge vesicles 9 ! lava 9 ! ?roat ( ! volcano1 & on com+ to ! surface explode1 hurl+ ! envelop+ lava upw>ds & outw>ds1 (t5 to great di/ances4 ,! viol5ce ( projection r$uces a portion ( ! lava to a f9ely divid$ /ate con/itut+ ! 8a%0 & 8smoke0 ( ! volcano4 ,o!r portions less divid$ are inflat$ by ! gases dissem9at$ ?r\gh !m1 & =m 8pumice0 & 8scoria10 accord+ to ! degree ( inflation1 :ile masses ( lava t h already solidifi$ into m or less r\nd$ masses 9 ! crat] are hurl$ =? z 8bombs02 n infrequ5tly portions ( ! walls ( ! crat] or ( ! duct bel[ are also disrupt$ & %ot =?4 ,diff]5ces 9 gas action4--,! causes ( ! diff]5ces ( gas action 9 diff]5t volcanoes are undet]m9$1 b ! foll[+ sugge/ions may po9t to a "p ( ! tru?3 7#a7 ,d\btless "s lavas conta9 m gases ?an o!rs1 & h5ce are pr$ispos$ to be m explosive2 7#b7 "s are m visc\s ?an o!rs & h5ce hold ! gases m t5aci\sly until !y accumulate & acquire explosive =ce1 :ile ! m liquid lavas all[ _! gases to escape m freely & easily2 7#c7 "s are hott] ?an o!rs1 & h5ce hold _! gases until aft] !y h escap$ f ! crat]1 :5 !y give !m (f f _! exp&$ surfaces 9 ! op5 air1 :]e !re is no re/ra9t to develop explosiv5ess2 7#d7 "s fl[s are s massive t !y cool to ! *ief gas-dis*>g+ po9t only aft] !y are spread out on ! surface1 :5 quiet escape is possible2 7#e7 probably a ma9 occasion ( ! v viol5t explosions lies 9 ! fact t ! lavas h begun to cry/allize :ile yet 9 ! duct ( ! volcano4 ,! cry/als1 9 =m+ 9 ! magma1 exclude ! gases f !mselves1 & ?is exclud$ portion ov]*>ges ! rema9+ portion ( ! lava4 ,?is process cont9ues z ! lava rises & gr[s cool] until ! gases acquire great volume & explosive =ce4 ,?is view is su/a9$ by ! fact t ! pumice & a% ( su* extraord9>ily explosive eruptions z ^? ( ,krakatoa & ,pele conta9 _m small cry/als :i* _h c]ta9ly =m$ be=e ! explosive inflation took place4 ,incipi5t cry/allization does n1 h[ev]1 appe> to be a univ]sal accompanim5t ( explosive action4 ,spasmodic action4--,! dis*>ge ( ! gases is spasmodic1 & usually consi/s ( a succession ( di/9ct explosions4 ,sometimes ^! succe$ "o ano!r at r con/ant & frequ5t int]vals1 z 9 ,/romboli1 :]e ! explosions foll[ "o ano!r at int]vals ( ?ree to t5 or m m9utes4 ,9 _m o!rs ! outbur/s are rhy?mic1 :ile 9 o!rs ! spasms are di/ant & irregul>4 ,k9ds ( gases4--,/eam is ! *ief volcanic gas4 ,its con/itu5ts1 hydrog5 & oxyg51 are also pres5t 9 ! free /ate1 & are p]haps ! result ( ! dissociation ( ! /eam at ! v high temp]atures ( ! lavas4 ,c>bon dioxide is probably next 9 abundance4 ,no positive /atem5t z to ! relative am\nts ( ! subord9ate gases c be made because ( ! obvi\s difficulties ( obta9+ any?+ l a repres5tative analysis ( ! gases conc]n$ 9 ! great volcanic eruptions4 ,! mat]ials = ! analyses :i* h be5 made 7 d]iv$ *iefly f little second>y or 8p>asitic0 v5ts1 or f side-wall crevices1 ?r\gh :i* ! volcanic gases rise4 ,su* v5ts probably d]ive _! gases f ! v bord] ( ! ma9 mass1 :]e x is mo/ subject to ! influ5ce ( wat]s & gases f ! adjac5t walls1 & x is unc]ta9 h[ f> !y are truly repres5tative ( ! gases 9 ! int]ior ( ! lava itself4 ,! data n[ at comm& seem to indicate t c>bon dioxide increases greatly 9 relative abundance z volcanic action dies away4 ,great quantities ( ?is gas are (t5 giv5 =? long aft] all signs ( active vulcanism h disappe>$4 ,su* gases h be5 attribut$ to ! action ( ! lavas on buri$ b$s ( lime/one or o!r c>bonates1 b 9 _m cases ! geology ( ! region (f]s no special support to ?is hypo!sis4 ,x does n seem inh]5tly probable t ! heat ( ! lava w\ld be suffici5t to decompose lime/one at a p]iod v long aft] ! active eruption4 ,an alt]native sugge/ion is t ! /rong] volcanic acids m5tion$ bel[ are gradually convey$ into ! adjac5t rocks & !re act on lime/ones or on p>tially c>bonat$ cry/all9e rocks1 sett+ free c>bon dioxide4 ,:atev] may be true ) reg>d to second>y gases ( ?is k9d1 x is q c]ta9 t ! lavas !mselves conta9 l>ge quantities ( c>bon dioxide1 & also ( c>bon monoxide1 d\btless r$uc$ f ! dioxide4 ,sulphur gases are v common accompanim5ts ( volcanic eruptions4 ,!y take ! =ms ( sulphurett$ hydrog5 & sulphur\s acid & p]haps ( sublimat$ sulphur1 all ( :i* are liable to pass by oxidation & hydration into sulphuric acid4 ,*lor9e & hydro*loric gases are also common1 p>ticul>ly at high temp]atures4 ,fluor9e & o!r gases are occasionally pres5t4 ,c]ta9 gases1 su* z hydrog5 & *lor9e1 are especially associat$ ) high temp]atures & en]getic action1 & are probably dep5d5t on !m4 ,hydro*loric acid & ! sulphur\s gases are also ma9ly associat$ ) high temp]atures1 :ile sulphurett$ hydrog5 is common] at l[] temp]atures4 ,oxyg51 nitrog51 & probably c>bon dioxide or c>bon monoxide are pres5t ?r\gh\t all ranges ( temp]ature4 ,nitrog5 is a r frequ5t b n v abundant con/itu5t ( ! volcanic gases4 ,h[ f> x results f admixture ( ! atmosph]e & h[ f> x is orig9al1 is n det]m9$4 ,x is1 h[ev]1 "o ( ! gases f\nd 9 volcanic rocks aft] !y h cool$1 & is presumably orig9al 9 "p4 ,a l>ge s]ies ( second>y vapors naturally arise f ! volatilization ( sub/ances conta9$ 9 ! lavas1 su* z ! oxides1 *lorides1 & sulphides ( ! metals1 etc4 ,residual gases 9 volcanic rocks4--,"s light ^u ! vital "q ( ! orig9al1 z di/+ui%$ f ! second>y gases ( lavas may be f\nd 9 ! analyses ( ! gases t rema9 9 ! lavas aft] !y are solidifi$4 ,:5 ! lavas lodg$ und]gr\nd )\t free communication ) ! surface1 !re is reason to ?9k t !y reta9$ a l>g] p]c5tage ( _! orig9al gases 9 solidification ?an 9 cases ( free exposure at ! surface2 at any rate1 su* rocks conta9 notable quantities ( gases occlud$ 9 "s way )9 !mselves4 ,rec5t surface-lavas also conta9 gases ( simil> k9ds1 b n 9 equal degree1 s f> z available analyses %[4 ,! gases are 9 "p held 9 num]\s small cavities )9 ! con/itu5t m9]als1 especially 9 ! qu>tz4 ,?is is p]haps due to ! fact t qu>tz usually cry/allizes late 9 ! process ( solidification1 & its "m-mat]ial becomes cr[d$ ) gases exclud$ by ! previ\s cry/allization ( o!r m9]als4 ,analyses ( tw5ty-five cry/all9e rocks ( v>i\s k9ds f _m typical localities by ,tild51#bhe gave an av]age volume ( gas1 "u ord9>y atmosph]ic pressure1 f\r & a half times t ( ! conta9+ rock4 ,?is %[s ! cond5s$ condition 9 :i* ! gases are held4 ,( ^! gases1 ! *ief is hydrog51 :i* mu* exce$s all ! re/4 ,next 9 ord] ( abundance is c>bon dioxide1 foll[$ by c>bon monoxide1 m>% gas 7,,*71 & nitrog54 ,wat] is frequ5tly pres5t & free oxyg5 almo/ univ]sally abs5t4 ,! av]age ratio ( hydrog5 to c>bon dioxide by volume 9 ^! analyses is ab\t #gj 3 #cj4 ,five complete analyses gave ! foll[+ av]ages3 ,h1 #eb4acd2 ,,co1 #cd4ajd2 ,,co1 #h4dbb2 ,,*1 #c4bbd2 ,n1 #b4jgb4 ,x w be se5 t ! gases conta9$ 9 ^! rocks are 9 proportions radically diff]5t f ^? ( ! atmosph]e1 & x is d\btful :e!r !y c be reasonably assign$ to any o!r s\rce ?an ! lavas f :i* ! rocks 7 =m$4 ,x is to be not$1 h[ev]1 t "s s$im5t>y & meta-s$im5t>y rocks1 su* z qu>tzite & qu>tz-s*i/1 conta9 simil> gases1 b ?is may be because ! granules ( ! orig9al rock reta9 !m1 not)/&+ ! second>y processes ?r\gh :i* !y h pass$4 ,analyses ( meteorites %[ ess5tially ! same gases 9 mu* ! same proportions4 ,if evid5ce ( ?is k9d c be tru/$1 ! /&>d orig9al gases ( lavas are ! elem5ts or comp\nds ( hydrog51 c>bon1 & nitrog51 9 ! ord] nam$1 :ile ! *lor9e & sulphur gases are to be reg>d$ z accessory4 ,because ( _! int5sely en]getic & noxi\s "*1 ^! latt] gases make !mselves disproportionately manife/ 9 ! vic9ity ( active volcanoes4 ,t !y are really n prepond]ant seems to be impli$ by ! fact t ! volcanic ra9s1 :i* are extremely copi\s1 are usually fre%1 & only 9 r>e cases is ! pres5ce ( ! hydro*loric or sulphur\s elem5ts suffici5t to produce noxi\s effects4 ,volcanic & meteoric data seem to indicate t /eam is held less t5aci\sly ?an ! o!r gases 9 ! magmas z !y solidify into rocks4 ,! s\rce ( ! gases4--,z already not$1 x is "o ( ! out/&+ problems ( geology to det]m9e 7a7 h[ f> ! gases ( lavas 7 possess$ by !m f _! orig91 :atev] t may be1 & 7b7 h[ f> !y h be5 acquir$ 9 ! lava's asc5t to ! surface4 ,x is recogniz$ t lavas h ! p[] ( absorb+ gases1 & "o ( ! views ent]ta9$ is t surface-wat]s1 p]colat+ ?r\gh ! rocks & com+ 9 contact ) ! asc5d+ column ( lava1 are conv]t$ into /eam1 :i* is absorb$ into ! lava & rises ) x to ! surface4 ,!re are two phases ( ?is view4 7#a7 ,! m cons]vative "o supposes t ! wat] m]ely p5etrates ! fracture zone ( ! surface ( ! e>? ?r\gh ! ord9>y means ( passage ( und]gr\nd-wat]s1 & s makes a comp>atively %ort circuit4 ,"u ?is view1 ! /eam & o!r gases giv5 =? are n a contribution to ! atmosph]e & hydrosph]e1 b m]ely a re/oration to !m ( wat] & dissolv$ gases previ\sly c>ri$ d[n f ! surface4 ,an ev5 n>r[] view is sometimes ent]ta9$ :i* supposes t ! l>g] "p ( ! wat] desc5ds ?r\gh ! volcanic cone itself1 or imm$iately ab\t its base4 ,! pres5ce ( *lor9e gases 9 ! volcanic emanations & ! ne>ness ( mo/ exi/+ volcanoes to ! sea h be5 ! basis = ! idea t sea-wat]1 p5etrat+ to ! lava1 is a *ief s\rce ( ! volcanic gases4 7#b7 ,! broad] phase ( ! view assumes t ! wat]s p5etrate n only ! out] fracture zone ( ! e>?1 :i* is probably limit$ to five or six miles 9 dep?1 b t !y diffuse !mselves ?r\gh ! cont9u\s unfractur$ zone d[n to dep?s :]e temp]atures ( fusion prevail1 & t !y !re ent] into comb9ation ) ! lavas or ) hot rock to =m lavas4 ,x is well kn[n t aque\s vapor facilitates ! fusion1 or m accurately1 ! mutual solution ( ! m9]als4 ,?is view is a "p ( "o ( ! hypo!ses conc]n+ ! orig9 ( ! lavas !mselves4 ,! oppos+ view supposes t ! gases 7 9 ! ma9 orig9al4 ,( ?is view !re are two phases3 7#a7 ,"o supposes t ! lavas are remnants ( an orig9al molt5 globe :i* absorb$ gases f ! primitive atmosph]e & reta9$ !m till ! "t ( _! eruption4 ,! possible absorption ( /eam & air into ! suppos$ molt5 globe has be5 mu* neglect$ 9 curr5t conceptions ( e>ly conditions4 ,if ! lavas ( ! suppos$ molt5 globe absorb$ proportionately z mu* wat]-vapor z ! volcanic lavas (t5 conta91 x w\ld probably take =ty or fifty times ! pres5t ocean & atmosph]e to supply !m4 ,any remnants ( ^! orig9al lavas might well be suppos$ to hold gases4 ,ev5 rocks d]iv$ f !m by deep-seat$ solidification might reta9 mu* gas4 7#b7 ,! o!r phase ( ! view assumes t ! gases 7 entrapp$ :5 ! globe 0 built up ( meteoroidal or planetesimal matt]1 z assum$ 9 ! accretion hypo!sis4 ,"u ei!r ( ! la/ two views ! gases may be said to be prim>y1 & g5etically connect$ ) ! orig9 ( ! lavas !mselves4 ,su* gases w\ld be a contribution to ! atmosph]e & ! hydrosph]e4 ,?is view does n exclude ! idea t z ! lava rises ?r\gh ! surface-rocks1 o!r gases are =m$ by contact1 & t !y may be absorb$ into ! ris+ column4 ,on ! contr>y1 ! view recognizes ! possibility t a tongue ( lava ris+ into ! upp] =mations may enc\nt] bodies ( wat]1 or masses ( ?or\ghly wat]-soak$ rock1 f :i* great quantities ( /eam may be g5]at$1 & t ?is accessory /eam may be a l>ge factor 9 ! initial explosion :i* (t5 accompanies ! developm5t ( a new volcano1 or ! new eruption ( an old "o aft] a long p]iod ( quiesc5ce4 ,a decision on ! vital "q :e!r ! volcanic gases are l>gely prim>y1 or are ess5tially second>y1 has n yet be5 rea*$2 b x w d\btless be rea*$ :5 a suffici5t numb] ( really repres5tative analyses ( volcanic gases h be5 made1 & :5 ! ph5om5a ( ! gases occlud$ 9 igne\s rocks h be5 ?or\ghly inve/igat$4 ,! peculi> proportions ( ! rock-gases1 9 :i* hydrog5 & c>bon dioxide s greatly prepond]ate1 seem to imply t !y are n d]iv$ f ! atmosph]e2 at lea/ if !y 7 s d]iv$1 !re mu/ h be5 a selective absorption ( a mo/ rem>kable k9d1 because hydrog5 is pres5t 9 ! atmosph]e 9 exce$+ly small quantities1 :ile c>bon dioxide is a v m9or con/itu5t4 ,at ! same "t1 z already rem>k$1 no free oxyg5 is usually f\nd 9 ^! absorb$ gases4 ,! "q z to :e!r ! l>g] "p ( ! volcanic gases is orig9al or is m]ely a special =m ( convective circulation1 has an important be>+ on ! supply ( ! atmosph]e1 :i* is con/antly be+ deplet$ by ! oxidation ( ! rocks & by ! =mation ( c>bonates & c>bonace\s deposits4 ,?is vital phase ( ! subject w receive fur!r consid]ation4 ,:ile recogniz+ ! lack ( decisive pro(1 x w\ld seem t ! prepond]ance ( evid5ce lies 9 favor ( ! view t a notable portion1 at lea/1 ( gase\s volcanic emanations is d]iv$ f ! int]ior ( ! e>?1 & is really a contribution to ! atmosph]e & ! hydrosph]e4 ,! hydrog51 on com+ 9 contact ) ! atmosph]e1 ignites & adds itself to ! hydrosph]e4 ,! c>bon dioxide is 9 "p decompos$ by plants1 & adds to ! supply ( atmosph]ic oxyg54 ,! nitrog51 be+ comp>atively in]t1 d\btless gradually accumulates 9 ! air & has ?us come to be its prepond]ant con/itu5t4 ,,! ,,cause ,,( ,,vulcanism4 ,! extraord9>y facts involv$ 9 volcanic ph5om5a _c well be discuss$ fully until ! orig9 ( ! e>? is consid]$1 & ! great ag5cies1 z well z ! peculi> conditions1 :i* ! e>? inh]it$ f its bir?1 are duly weigh$1 = ^! 71 ) little d\bt1 ! true causal antec$5ts ( vulcanism4 ,we %all return to ! subject aft] a sket* ( ! e>ly conditions ( ! e>?1 b ! views t h be5 ent]ta9$ may be review$ "h :ile ! ph5om5a are fre% 9 m9d4 ,! explanation ( vulcanism involves two ess5tial elem5ts4 ,^! are 7#a7 ! orig9 ( ! lavas1 :i* involves a consid]ation ( ! necess>y temp]atures1 pressures1 & o!r conditions1 & 7#b7 ! =ces by :i* ! lavas are expell$4 ,ne>ly all curr5t explanations ( vulcanism are f\nd$ ^u conditions suppos$ to be d]iv$ f a molt5 globe1 & fall "u two g5]al classes3 7,i7 ^? :i* assume t ! lavas are residual portions ( ! orig9al molt5 mass1 & 7,,ii7 ^? :i* assign ! lavas to ! local melt+ ( rock4 ,i4 ,on ! ,assumption t ! ,lavas are ,orig9al4 ,9 ?is case x is n necess>y to assume any special accession ( heat1 b m]ely to acc\nt = extrusion4 ,!re are two phases ( ?is view1 7#a7 ! "o po/ulat+ a g5]al molt5 int]ior1 7#b7 ! o!r limit+ ! molt5 matt] to local res]voirs4 ,hypo!sis ,i4 ,lava outfl[s f a molt5 int]ior4--,9 ! e>ly days ( geology1 :5 ! e>? 0 suppos$ to h a ?9 cru/ & a molt5 int]ior1 x 0 v naturally assum$ t volcanoes 7 b pipes lead+ d[n to ! molt5 mass )94 ,?is view has be5 ess5tially ab&on$4 ,! indep5d5ce ( adjac5t v5ts is 9 itself almo/ a fatal objection1 :5 x is recall$ t ! height ( rec5t volcanic crat]s ranges f ne>ly #bj1jjj feet above ! sea1 to #aj1jjj to #bj1jjj feet bel[4 ,! view w\ld involve ! conception ( lava-columns connect$ ) a common res]voir v>y+ possibly #cj1jjj to #dj1jjj feet 9 altitude1 & c]ta9ly m ?an half t mu*1 simultane\sly4 ,! l[] outlets %\ld z c]ta9ly be select$ = ! outfl[ ( ! great int]ior sea ( fluid rock1 z ! l[e/ sag 9 ! rim ( a lake = its outfl[1 = no great diff]5ces 9 specific gravity are presumable "u ?is hypo!sis4 ,an equally grave objection arises f tidal /ra94 ,if ! e>? 7 liquid )9 & m]ely cru/$ ov] by a %ell ( rock ( mod]ate ?ickness1 x w\ld yield appreciably to tidal /resses1 & ?is yield+ w\ld *ange ! capacity ( ! int]ior s t ) e di/ortion ( ! sph]oid a portion ( its fluid int]ior w\ld be =c$ to ! outside1 & ) e return to ! m sph]oidal =m !re w\ld ei!r be a re-fl[ to ! int]ior or a %r9k+ ( ! cru/4 ,9 any case a v demon/rative response to tidal influ5ce w\ld tell ! /ory ( int]ior fluidity4 ,no su* effects are obs]v$4 ,! tidal /ra9s may p]haps h a slight effect 9 ha/5+ a giv5 eruption :5 ! =ces are approa*+ a delicate balance & an eruption is imm95t1 b ! v triviality ( ?is influ5ce implies n only ! abs5ce ( a g5]al liquid int]ior1 b also ( ext5sive res]voirs4 ,hypo!sis #b4 ,lavas assign$ to molt5 res]voirs4--,a modification ( ! prec$+ view has be5 made to escape ! difficulties involv$ 9 ! hypo!sis z /at$ above4 ,x is suppos$ t :ile ne>ly all ! subcru/ solidifi$1 num]\s liquid spots 7 left scatt]$ ?r\gh x4 ,?is honeycomb$ sub/ratum is suppos$ to connect ! cont9u\s out] cru/ ) a c5tral solid body1 solidifi$ because ( pressure 9 spite ( its high temp]ature4 ,?is hypo!sis escapes only a portion ( ! objections4 ,= in/ance1 ! lavas 9 ,mauna ,loa & ,kilauea 9 ,hawaii diff] ne>ly #aj1jjj feet 9 height1 & h5ce _c well be suppos$ to connect ) ! same res]voir1 b !y are bo? on ! same va/ cone1 :i* implies at lea/ an equally l>ge molt5 res]voir z its s\rce4 ,if !re 7 two di/9ct res]voirs ( ! requir$ magnitude1 !y mu/ be s+ul>ly plac$ to supply v5ts s ne> & yet s indep5d5t4 ,! difficulty gr[s great] :5 ! :ole ,hawaiian *a9 is consid]$1 = ! po9ts ( eruption seem to h migrat$ f ! nor?we/]ly isl&s1 :]e ! volcanoes are old1 to ! s\!a/]n end1 :]e volcanic activity is n[ 9 progress4 ,x w\ld be natural "u ?is view to suppose t ^! residu>y lakelets ( liquid rock %\ld be gradually exhau/$ z "t goes on1 & t vulcanism %\ld be a decl9+ ph5om5on4 ,x is n cle> t ?is is ! case4 ,! great numb] ( exi/+ volcanoes 9 regions :]e great extrusions took place 9 e>li] ages does n seem to be 9 h>mony ) ! hypo!sis4 ,,ii4 ,on ! ,assumption t ! ,lavas are ,second>y4 ,! s]i\s difficulties t arise 9 int]pret+ volcanic lavas z remnants ( an orig9al molt5 mass1 & ! /rong argum5ts ( rec5t ye>s = a v solid e>?1 h turn$ inquiry *iefly t[>d ! second class ( hypo!ses1 :i* ref] ! orig9 ( lavas to ! local melt+ ( deep-seat$ rock4 ,^! diff] widely among !mselves4 ,"o gr\p seeks = a cause ( ! melt+ 9 ! p5etration ( surface air & wat]2 ano!r1 9 ! relief ( pressure2 a ?ird1 9 cru%+ & %e>+2 a f\r?1 9 ! depression ( s$im5ts into ! heat$ int]ior zone2 & a fif?1 9 ! outw>d fl[ ( deep-seat$ heat4 ,hypo!sis #c4 ,lavas assign$ to ! reaction ( wat] & air p5etrat+ to hot rocks4--,z /eam is "o ( ! great factors 9 ! explosions ( volcanoes1 & z wat] r$uces ! melt+-po9t ( rocks1 x is a natural & simple view t wat] p5etrat+ ?r\gh ! fissures & pores ( ! out] cru/ & com+ into contact ) ! heat$ rocks bel[1 is absorb$ into !m & r5d]s !m liquid1 & t !n1 be+ r5d]$ swoll5 & light] by ! process1 !y asc5d & dis*>ge quietly or explosively accord+ to ! special conditions ( ! case4 ,naturally ! sugge/ion arises t ! wat]s w\ld be conv]t$ into /eam long be=e !y c\ld rea* rock hot en\gh to be melt$1 & t ?is /eam w\ld be =c$ back along its own track1 z ! l9e ( lea/ resi/ance1 r ?an =ce itself into ! rock mat]ial & rise 9 ! lava-column2 b to ?is x is answ]$ t an exp]im5t ( ,daubree's has %[n t wat] w p5etrate ! capill>ies ( s&/one aga9/ high /eam pressure & add itself to ! /eam )94 ,! fact is also cit$ t c]ta9 sub/ances1 :5 highly heat$1 absorb gases :i* !y give out :5 !y cool4 ,! absorption ( hydrog5 by plat9um1 & ( oxyg5 by molt5 silv]1 are illu/rations4 ,x is c]ta9 t ! lavas d conta9 l>ge quantities ( absorb$ gases1 & t ^! are p>tly1 & 9 mo/ cases l>gely1 giv5 out 9 cool+1 :5 ! cool+ takes place at ! surface4 ,! presumption is t ! lavas w\ld take ! gases up aga9 on remelt+ "u simil> conditions4 ,if ! lavas ( actual volcanoes _h ! temp]atures ( aqueo-igne\s fusion 7#gjj-ajjj ,fahr47 only1 x w\ld /r5g!n ?is view2 b z temp]atures ( lavas (t5 exce$ #bjjj ,fahr41 & probably sometimes rea* #bejj ,fahr41 & p]haps #cjjj ,fahr41 x is n easy to acc\nt = su* temp]atures "u ?is hypo!sis1 because !y w\ld only be rea*$ at levels f> bel[ ^? at :i* aqueo-igne\s fusion might be presum$ to take place4 ,p]haps ?is c\ld be met by invok+ pressure :i* might prev5t ev5 aqueo-igne\s fusion f tak+ place until ^! temp]atures 7 rea*$1 b pressure br+s 9 a grave difficulty 9 ano!r l9e1 z we %all pres5tly see4 ,!re is a phase ( ! wat]-p5etration hypo!sis :i* seeks to acc\nt = an accession ( heat4 ,x is affirm$ t ! out] rocks are oxidiz$1 :ile ! inn] ones 7 n orig9ally1 or at lea/ n completely oxidiz$1 & t air & wat] f ! surface1 rea*+ ! unoxidiz$ zone1 ent] into comb9ation & g5]ate ! necess>y heat4 ,?is view 0 p>donable be=e ! developm5t ( mod]n !rmo-*emi/ry1 b is n[ q unt5able1 z may be %[n by work+ out ! reactions !rmally4 ,all views :i* assign ! p5etration ( surface air or wat] z a cause meet ) a grave1 if n insup]able1 difficulty 9 ! condition ( ! l[] "p ( ! e>?'s cru/ 7see p4 #bah74 ,! fractur$ condition ( ! cru/1 :i* p]mits a ready p5etration ( wat]1 is a v sup]ficial ph5om5on4 ,bel[ ! fir/ few ?\s& feet ! crevices & porosities ( ! rock are rapidly clos$ by ! pressure ( ov]ly+ rock1 & all appreciable crevices & pores probably disappe> at a dep? ( five or six miles4 ,! effective function ( fissures is1 !re=e1 limit$ to ! upp] few miles ( ! cru/1 & ev5 "h to c]ta9 portions only4 ,! great pressures 9 gas- & oil-wells %[ t 9 _m q sup]ficial b$s1 ev5 :5 ar*$1 !re are no fissures or pores capable ( lett+ ev5 gas escape effectively4 ,! dep?s at :i* ! temp]atures ( lavas are rea*$ are usually e/imat$1 f ! d[nw>d increase ( temp]ature1 at #bj to #cj miles4 ,?is leaves f #ad to #bd miles ( ! compress$ zone betwe5 ! l[e/ assignable limit ( ! fissur$ zone1 & ! highe/ assignable zone = ! orig9 ( lavas4 ,?is ?ick zone ( d5se rock mu/ be reckon$ ) 9 all hypo!ses t involve ! p5etration ( air & wat] f )\t1 &1 z well1 ! extrusion ( lavas f )94 ,9 addition to ! difficulties ( ! p5etration ( gr\nd-wat]1 ! limitations ( its heat1 at p5etrable dep?s1 also be> adv]sely 7see p4 #bai71 on ! desc5t ( air & wat]4 ,hypo!sis #d4 ,lavas assign$ to relief ( pressure4--,x seems to be demon/rat$ t pressure raises ! melt+-po9t ( av]age rock1 & h5ce at tw5ty or ?irty miles' dep? !re may be rocks hot en\gh to melt at ! surface1 b /ill solid because ( high pressure4 ,if ?is pressure 7 9 "s way reliev$ !y w\ld become liquid4 ,pressure may be locally reliev$ some:at 7#a7 by d5udation1 7#b7 by c]ta9 phases ( fault+1 7#c7 by anticl9al ar*es1 & 7#d7 by cont95tal de=mation4 7#a7 ,9 mo/ cases ( d5udation1 cool+ bel[ probably keeps pace ) loss above4 ,at any rate1 _m volcanoes rise f ! bottoms ( ! oceans :]e no d5udation takes place1 & ?is phase ( ! hypo!sis is n workable !re4 7#b7 ,! !ory ( relief by fault+ f9ds enc\ragem5t 9 ! fact t _m volcanoes occur on fault-l9es4 ,!re is no evid5ce1 h[ev]1 t ?is is a univ]sal or necess>y relation4 ,computation z to ! am\nt ( l[]+ ( ! melt+-po9t t might arise f ! fault+ associat$ ) volcanoes indicates t x is necess>y to suppose t ! rocks 7 already v close to ! melt+-po9t :5 ! fault+ took place1 to make ! doctr9e applicable4 ,x is to be obs]v$ t 9 fault+ ! relief ( pressure on "o side ( ! fault-l9e is likely to be balanc$ by increas$ pressure on ! o!r side1 & t ?is diff]5ce 9 pressure may be lo/ by di/ribution at a dep? ( #bj or #cj miles1 :]e1 at ! ne>e/1 ?is delicate relation betwe5 solidity & liquidity1 on :i* ! !ory is dep5d5t1 may p]haps be rea*$4 7#c7 ,imm$iately "u an anticl9al ar* !re may d\btless be "s relief ( pressure )9 ! limits ( /r5g? ( ! ar*1 :i* is n great 7p4 #ehb74 ,! pressure "u ! ar* z a :ole is great] ?an be=e x 0 b[$ up by lat]al ?ru/1 & 9 dep? ?is excess becomes di/ribut$ s z to oblit]ate ! local relief "u ! c5t] ( ! ar*1 & s adds ! effects ( fold+ to ! av]age pressure ( ! cru/4 ,besides1 z a matt] ( fact1 volcanoes d n appe> to be especially associat$ ) m\nta9 folds :]e ar*+ rea*es its be/ expression4 7#d7 ,! same g5]al consid]ations be> on ! assignm5t ( liquefaction to relief ( pressure 9 connection ) ! m g5]al de=mation ( ! e>?'s body4 ,besides1 :ile relief ( pressure might acc\nt = liquefaction1 x leaves ! extrusion )\t an obvi\s cause2 inde$1 x w\ld seem to furni% a condition oppos$ to extrusion1 & if pressure 7 subsequ5tly add$ to =ce ! liquid out1 x w\ld t5d to re/ore ! solid condition4 ,hypo!sis #e4 ,lavas assign$ to melt+ by cru%+4--,mallet#bhf & o!rs h attribut$ melt+ to ! cru%+ ( rock4 ,cru%+1 9 ! ord9>y s5se ( ! t]m1 c only take place 9 ! zone ( fracture1 & t is app>5tly too %all[ to meet ! requirem5ts ( ! case4 ,bel[ ?is zone1 ! pressure on all sides is too great to p]mit any sep>ation ( fragm5ts1 & a solid mass c only *ange its =m by :at is call$ 8solid fl[age40 ,! rock "u ^! conditions may be compress$1 & ?is compression mu/ give rise to heat1 b at ! same "t ! melt+-po9t is rais$1 accord+ to all exp]im5ts4 ,x seems improbable t melt+ c be produc$ 9 ?is way4 ,if great pressure c\ld be br\ght to be> ^u a tract ( rock s z to heat x by compression1 & if !n ! pressure 7 relax$ be=e ! heat g5]at$ c\ld be di/ribut$ by conduction1 & if re-expansion did n foll[1 possibly melt+ c\ld be effect$1 b ?is makes ! process complicat$ & app>5tly inapplicable4 ,x is sc>cely possible t su* a sequ5ce ( ev5ts c h affect$ all ! tracts t are n[ volcanic1 mu* less all ^? t h be5 su* ?r\gh\t geologic hi/ory4 ,z not$ 9 ! prec$+ case1 relaxation w\ld seem to be unfavorable to expulsion4 ,besides1 volcanoes d n seem to be conf9$ to tracts t %[ signs ( great crumpl+ & cru%+1 z ! ,alps1 ! ,appala*ians1 & ! closely fold$ ranges g5]ally4 ,extrusions seem r m common ) fault$ ranges :]e cru%+ is less notable & :]e surface t5sion replaces compression4 ,hypo!sis #f4 ,lavas assign$ to melt+ by depression4--,x is obs]v$ t 9 c]ta9 regions great ?icknesses ( s$im5ts h accumulat$ by ! sl[ settl+ ( ! cru/ bel[1 & z ^! s$im5ts ob/ruct ! outw>d fl[ ( heat :ile ! l[] b$s settle ne>] to ! int]ior s\rce ( heat1 x is conceiv$ t !y become heat$ bel[ &1 be+ saturat$ ) wat]1 take on aqueo-igne\s fusion & rise z lavas1 well suppli$ ) int]nal gas & /eam f ! wat] & volatile con/itu5ts t 7 entrapp$ & c>ri$ d[n ) !m4 ,! "q obvi\sly arises :e!r su* depression is suffici5t to give ! temp]atures ! lavas %[1 & :e!r volcanic action is conf9$ to su* areas ( depression & deep s$im5tation4 ,at ! highe/ cr$ible e/imates--:i* are none ! less to be tak5 ) res]ve--! po/-,ar*ean s$im5ts r>ely rea* five or six miles 9 ?ickness at any giv5 po9t1 & probably nev] exce$ t5 or twelve1 :ile tw5ty or ?irty miles is ! comput$ dep? requir$ = ! acquisition ( ! temp]atures ! lavas actually possess4 ,if ! ,ar*ean t]ranes be includ$ among ! s$im5t>ies1 ! ?ickness may be adequate1 b :at !n ( ! ,ar*ean vulcanism1 :i* mu* surpasses t ( lat] times1 & ! o!r e>ly extrusions be=e ! s$im5ts 7 ?ick2 & :at ( ! moon1 :]e !re are probably no s$im5ts at all8 ,besides1 x is n at all cle> t ! di/ribution ( vulcanism is specially relat$ to t ( ?ick s$im5ts1 z x %\ld be if ?is hypo!sis 7 ! true "o4 ,!re are _m volcanoes 9 ! he>t ( ! great oceans :]e s$im5tation is n[ inappreciable1 & probably has be5 9 all pa/ p]iods4 ,hypo!sis #g4 ,vulcanism assign$ to ! outfl[ ( deep-seat$ heat4--,if ! e>? grew up by sl[ accessions ( meteoroidal or planetesimal matt]1 9 a mann] to be m fully set =? 9 ! discussion ( ! orig9 ( ! e>?1 & if its int]ior heat be due *iefly to compression by its own gravity1 ! int]nal temp]ature w\ld be orig9ally di/ribut$ accord+ to ! degree ( compression1 & ?is w\ld dep5d on ! int5sity ( ! int]nal pressure4 ,?is c be approximately comput$1 & is %[n 9 ! diagram on page #efc1 :]e ?is subject has be5 treat$4 ,on n improbable assumptions reg>d+ ! !rmometric conductivity1 ! fl[ ( heat f ! deep int]ior to ! middle zone w\ld be great] ?an ! loss ( ?is zone to ! sup]ficial zone4 ,?is middle zone %\ld1 "u ?is view1 exp]i5ce a ris+ temp]ature4 ,by hypo!sis1 ?is zone is compos$ ( v>i\s k9ds ( matt] mix$ z !y happ5$ to fall 94 ,h5ce z ! temp]ature rises1 ! fusion-po9ts ( "s ( ^! con/itu5ts w be rea*$ be=e ^? ( o!rs4 ,m /rictly1 ! temp]atures at :i* "s ( ^! con/itu5ts w mutually dissolve "o ano!r w be rea*$1 :ile o!r con/itu5ts rema9 undissolv$1 & ?us a p>tial & di/ribut$ liquefaction w arise4 ,! gases & volatile con/itu5ts 9 ! mix$ mat]ial w\ld naturally ent] l>gely into ! liquefi$ portion4 ,x is assum$ t ) a cont9u$ rise ( temp]ature1 ! p>tial liquefactions w\ld increase until ! liquefi$ p>ts f\nd means ( unit+1 & ! light] portions1 embrac+ ! gase\s cont+5t1 7 able to "w _! way t[>d ! surface4 ,z !y rose by fus+ or flux+ _! way1 ! pressure ^u !m became less & less1 & h5ce ! temp]ature necess>y = liquefaction gradually fell1 leav+ !m a con/antly r5ew$ m>g9 ( temp]ature available = melt+ _! way ?r\gh ! upp] horizons4 ,?us x is conceiv$ t ^! fusible & flux+ selections f ! middle zone might ?read _! ways up to ! zone ( fracture & !nce1 tak+ advantage ( fissures & fractures1 rea* ! surface4 ,x is conceiv$ t su* liquefaction & extrusion w\ld c>ry out f ! middle zone ! excess ( temp]ature receiv$ f ! deep] int]ior1 & ?us regulate its temp]ature & =e/all g5]al liquefaction1 ! zone z a :ole rema9+ always solid4 ,! indep5d5ce ( volcanoes is assign$ to ! indep5d5ce ( ! liquid ?reads t work$ _! way to ! surface4 ,no?+ l a res]voir or molt5 lake ent]s into ! conception4 ,! prolong$ action ( volcanoes is attribut$ to ! sl[ fe$+ ( ! liquid ?reads f ! locally fus$ middle zone4 ,! frequ5t pauses 9 action are assign$ to tempor>y defici5cies ( supply2 ! r5ewals to ! ga!r+ ( new supplies aft] a suffici5t p]iod ( accumulation4 ,! di/ribution ( volcanoes 9 ess5tially all latitudes & longitudes is assign$ to ! g5]al nature ( ! cause4 ,! special surface di/ributions are assum$ to be influ5c$1 ?\gh n altoge!r controll$1 by ! favorable or unfavorable conditions = escape pres5t$ by ! cru/al segm5ts ( ! e>?4 ,! p]si/5ce ( volcanic action 9 "t is attribut$ to ! magnitude ( ! int]ior s\rce1 to its deep-seat$ location1 & to ! sl[ness ( conduction ( heat 9 ! e>?'s int]ior4 ,! =ce ( expulsion is f\nd 9 ! /ress-diff]5ces 9 ! int]ior1 p>ticul>ly ! p]iodic tidal & o!r a/ronomic /resses 7see p4 #ehj71 & 9 ! sl[ pressure br\ght to be> on ! sl5d] ?reads ( liquid by ! creep ( ! adjac5t rock4 ,! viol5t expulsions are due to ! includ$ gases1 ( :i* /eam is *ief4 ,little effici5cy is assign$ to surface-wat]s1 & t little is reg>d$ z :olly second>y & incid5tal4 ,! true volcanic gases are reg>d$ z com+ f ! deep int]ior & z be+ true accessions to ! atmosph]e & hydrosph]e4 ,! /&+ ( ! lavas 9 volcanic ducts = hundr$s & ev5 ?\s&s ( ye>s ) only small outfl[s1 z 9 "s ( ! be/-kn[n volcanoes1 is reg>d$ z an exhibition ( an approximate equilibrium betwe5 ! hydro/atic pressure ( ! deep-p5etrat+ column ( lava1 & ! fl[age-t5d5cy ( ! rock-walls1 ! outfl[ be+1 ( c\rse1 also condition$ on ! sl[ rate ( supply bel[1 & ! p]iodic /ress-diff]5ces ( ! int]ior4 ,= ! pres5t ^! hypo!ses mu/ be left to "w out _! own de/9y1 s]v+ 9 ! mean "t z /imulants ( rese>*4 ,all b ! la/ h be5 = "s "t "u ! consid]ation ( geologi/s1 & are set =? 9 ! lit]ature ( ! subject 7p4 #fcf74 ,a few special phases ( ! problem ne$ fur!r discussion1 ?\gh !y h be5 incid5tally t\*$ ^u4 ,modes ( ,rea*+ ! ,surface4 ,all ( ! views t locate ! orig9 ( ! lavas deep 9 ! e>? mu/ face ! difficulties ( ! passage ?r\gh ! d5se portion ( ! sph]e bel[ ! fracture zone4 ,ne> ! surface1 ! lavas usually take advantage ( fissures or b$d+-planes already exi/+ or made by !mselves4 ,!re is little evid5ce t !y bore _! way by melt+1 ?\gh !y r\nd out _! ducts into pipes z !y use !m1 mu* z /reamlets on glaci]s fall+ into crevices r\nd out m\l9s4 ,b ?is use ( fissures & b$d+-planes = passage is probably m]ely a matt] ( lea/ resi/ance :]e ! lavas are relatively cool1 & _! capacity = melt+ is l[ or p]haps ev5 gone4 ,daly has rec5tly urg$ t lavas "w out res]voirs & enl>ge passageways = !mselves by deta*+ masses ( rock f ! ro(s & sides ( ! spaces already occupi$ by !m1 ^! masses ei!r melt+ & m+l+ ) ! lava1 or else s9k+ to l[] positions 9 ! column4 ,?is process he designates /op+4#bhg ,9 ! d5s] & w>m] zone bel[1 ! alt]natives seem to be 7#a7 melt+ or flux+1 or 7#b7 me*anical p5etration )\t fracture4 ,z rocks 8fl[0 9 ?is zone by diff]5tial pressure )\t rupture1 an includ$ liquid mass may be =c$ to fl[ ?r\gh ! zone by suffici5t diff]5tial pressure4 ,if local diff]5tial pressures at ! surface be neglect$ z probably incompet5t1 !re only rema9 ! /ress-diff]5ces ( ! int]ior & ! diff]5ces ( hydro/atic pressure betwe5 ! lava-column & ! surr\nd+ solid columns4 ,! latt] w\ld n be great until a column ( liquid ( mu* dep? 0 =m$1 & ! =m] w\ld probably n be conc5trat$ on ! liquid 9 su* a way z to =ce x bodily ?r\gh ! solid rock4 ,probably fus+ or flux+ its way ) ! aid ( /ress-diff]5ces is ! *ief res\rce ( ! lava 9 ! initial /ages4 ,9 ?is x may be suppos$ to be assi/$ by its gases1 by its selective fusible & flux+ nature1 by its v high temp]ature if x comes f v great dep?s1 z held 9 ! sev5? hypo!sis1 & by ! /ress-diff]5ces :i* prevail 9 ! deep int]ior1 z %[n 9 ! la/ *apt]4 ,9 asc5d+ f l[] to high] horizons1 ! lava w\ld be con/antly invad+ regions ( l[] melt+-po9t because ( less pressure4 ,x w\ld ?us always h an excess ( heat above ! local melt+ temp]ature until x invad$ ! ext]nal1 cool zone1 :]e ! regional temp]ature is bel[ ! melt+-po9t ( surface pressure4 ,f t po9t on x mu/ con/antly lose portions ( its excess ( temp]ature by contact ) cool] rocks1 & probably 9 ! process ( flux+ its way 9 ! compact zone4 ,if ?is excess is insuffici5t to enable x to rea* ! zone ( fracture1 ! asc5d+ column is arre/$ & becomes m]ely a plutonic pipe or mass4 ,if x suffices to rea* ! zone ( fracture1 advantage may be tak5 !reaft] ( fissures & ( ruptur+1 & ! problem ( fur!r asc5t probably becomes *iefly "o ( hydro/atic pressure1 9 :i* ! asc5t ( ! lava-column is favor$ by its high temp]ature & its includ$ gases4 ,! hydro/atic conte/ is "h betwe5 ! lava-column1 measur$ to its extreme base1 & ! adjac5t rock-columns1 measur$ to ! same extreme dep?4 ,! result is1 !re=e1 n necess>ily dep5d5t on ! fl[age ( ! out] rocks1 b may be ess5tially or :olly dep5d5t on ! deep-seat$ fl[age ( ! rock ( ! l[] horizons4 ,! asc5d+ column may rea* hydro/atic equilibrium be=e x rea*es ! surface1 & may !n =m und]gr\nd intrusions ( v>i\s sorts )\t sup]ficial eruption1 or x may only f9d equilibrium by com+ to ! surface & p\r+ out a portion ( its sub/ance & dis*>g+ its gases4 ,additional ,consid]ations ,relative to ! ,gases4 ,! "q :e!r ! volcanic gases are a contribution to ! atmosph]e & hydrosph]e is s important 9 its be>+s on ! :ole hi/ory ( ! atmosph]e z to m]it additional consid]ation "h4 ,z already not$1 if ! volcanic gases arise f wat] & absorb$ air t h previ\sly pass$ d[n ?r\gh ! /rata1 !re is no real contribution to ! hydrosph]e & atmosph]e1 b m]ely circulation4 ,if ! gases are *iefly d]iv$ f ! deep int]ior1 !y are an important accession to ! atmosph]e & hydrosph]e4 ,mo/ views are m or less int]m$iate1 assign+ a "p ( ! gases to ! int]ior & a "p to ! ext]ior4 ,no "o w "q t "s "p at lea/ ( ! /eam is due to ! contact betwe5 ! gr\nd-wat]s & ! hot lava1 & probably no "o w "q t "s gas comes f ! int]ior if ! lavas orig9ate !re4 ,! vital "q is1 :5ce comes ! major portion8 ,are ! con/ant ebullitions ( "s volcanoes & ! t]rific explosions ( o!rs due ma9ly to surface-wat]s1 or to int]ior gases8 ,x seems to be c]ta9 t 9 mo/ cases ! gases are diffus$ ?r\gh ! sub/ance ( ! lava1 & are n simply 9 contact ) ! walls ( ! column or ) its summit4 ,)\t d\bt /eam is g5]at$ ar\nd ! lava-column by ext]nal contact1 & p]haps "s explosions are due to ! entrance ( ! ris+ lava ^u a crevice or cav]n fill$ ) wat]1 or to ! invasion ( a lake ga!r$ 9 an old crat]2 b x /ill rema9s a "q :e!r ! importance ( su* explosions has n be5 exagg]at$4 ,su* action does n seem compet5t to produce inflat$ lavas1 b m]ely %att]$ ones4 ,wat] ?us 8sudd5ly fla%$ into /eam0 c\ld sc>cely diffuse itself intimately ?r\gh ! lava1 = ! process ( diffusion is exce$+ly sl[4 ,b inflat$ lavas1 pumice1 scori1 & c9d]s are ! typical products ( explosive vulcanism4 ,n only 9 ! ord9>y ,vesuvian type1 b 9 ! extraord9>y ,krakatoan type1 inflat$ lavas are ! dom9ant product4 ,prodigi\s quantities ( ?is cov]$ ! sea ab\t ,krakatoa aft] its trem5d\s explosion 9 #ahhc4 ,judd e/imates t ! volume ( includ$ /eam involv$ 9 ! inflation ( ! pumice exam9$ by him1 0 f ?ree to five times t ( ! rock1 & t ! am\nt involv$ 9 explod+ ! lava into ! f9e du/ t float$ 9 ! upp] atmosph]e = mon?s1 0 presumably mu* great]4 ,if ! sudd5 fla%+ into /eam ( bodies ( wat] 9 ext]nal contact ) hot lava be reject$ z only an incid5tal s\rce ( explosion1 x rema9s to be consid]$ :e!r wat]s p]meat+ ! rock & becom+ conv]t$ into /eam may n be absorb$ into ! ris+ lava1 become diffus$ ?r\gh x1 & asc5d+ ) x1 explode at ! surface4 ,s f> z access ?r\gh fissures & cavities l>ge en\gh to be ent]$ by lava are conc]n$1 x may safely be conclud$ t s9ce ! hydro/atic pressure ( ! lava mu/ be great] ?an t ( ! wat] 9 ! fissures1 or else x c\ld n rise1 ! lava w ent] !m1 =c+ back ! wat] or ! /eam g5]at$ f x1 &1 hav+ p5etrat$ z f> z accessible1 w solidify z a dike1 & plug up ! av5ue ( contact betwe5 ! gr\nd-wat] & ! portion ( ! lava /ill rema9+ molt54 ,! num]\s dikes t att5d volcanic necks te/ify to ! preval5ce ( ?is action4 ,! capill>y pores ( ! wall-rock1 :i* _c be ?us bodily occupi$ by ! lava1 mu/ d\btless become fill$ ) /eam1 & ?is1 foll[+ ! pr9ciples ( ,daubree's exp]im5t1 w =ce itself into contact ) ! lava & be absorb$ by x1 b :e!r ?is w be 9 suffici5t quantity1 & w become suffici5tly diffus$ ?r\gh ! body ( ! lava-column to produce ! obs]v$ effects1 is an op5 "q4 ,! increas+ te/imony ( deep m9+ is t relatively little wat] fl[s ?r\gh ! deep] horizons4 ,x is urg$ t ! wat] rema9+ 9 solidifi$ lavas is v unequal 9 di/ribution1 z ?\gh due to unequal access & p>tial diffusion4 ,! argum5t seems /rong1 b to make x ?or\ghly good1 x mu/ be %[n t ?is inequality is n due to irregul>ity ( dis*>ge ( ! gases dur+ & aft] eruption1 r ?an to irregul>ity ( orig9al accession4 ,!re is1 p]haps1 z mu* gr\nd = assign+ diff]5ces 9 ! degree ( p>t+ ) ! includ$ gases1 z 9 acquir+ !m4 ,d\btless ^? lavas t boil$ & see!d = a long p]iod 9 ! caldron 7 m fully depriv$ ( _! gases ?an ^? t 7 m promptly disgorg$ & cool$ ) less convection & surface exposure4 ,!rmal consid]ations4--,probably ! mo/ important consid]ation relates to ! heat effects4 ,if und]gr\nd-wat]s ent] ! lava-column & come =? z /eam1 great quantities ( heat are consum$ 9 ! process4 ,has ! lava a suffici5t excess ( heat to /& ?is8 ,c ebullition be ma9ta9$ = ! obs]v$ p]iods if ! /eam comes f gr\nd-wat]s8 ,_m lavas probably d n c>ry a v l>ge excess ( heat above t necess>y = liquefaction1 = n a few ( !m conta9 cry/als already =m+1 :i* %[s t !y are )9 ! range ( ! temp]atures ( solidification ( _! con/itu5ts4 ,! same conclusion is indicat$ by ! limit$ fus+ effects %[n by ! walls ( dikes & sills4 ,on ! o!r h&1 z already rem>k$1 dikes & sills (t5 %[ ! effects ( a r rapid cool+ f ! walls4 ,! me?od ( fl[ (t5 implies ! same condition = ! acidic lavas1 s9ce !y usually behave z /iff1 pa/y masses ( limit$ liquidity4 ,on ! o!r h&1 ! basic lavas1 ^: fusion-po9t is mu* l[]1 (t5 fl[ freely & rea* great di/ances be=e solidify+4 ,! facts tak5 altoge!r imply t ! av]age temp]ature ( ! lavas is n mu* above ! fus+-po9t ( ! acidic lavas1 :ile x may probably be v consid]ably above ! fus+-po9t ( basalt4 ,= a r\gh e/imate1 ) no pret5sions to accuracy1 x may be assum$ t 9 an av]age case !re are #ejj ,fahr4 excess1 b probably n #ajjj ,fahr4 ,a computation bas$ on ev5 s r\gh an e/imate z ?is may1 by %[+ ! ord] ( magnitude ( ! !rmal consid]ations1 indicate _! radical be>+4 ,! av]age temp]ature ( ! gr\nd-wat] ( ! upp] two or ?ree miles ( ! cru/--! only portion ?r\gh :i* wat] probably p5etrates ) suffici5t fre$om to be effective 9 ?is case--is probably less ?an #bjj ,fahr4 ,! specific heat ( rock appe>s to av]age some:at less ?an #j4b4 ,! temp]ature ( ! lava may be tak5 at #cjjj ,fahr4 z a suffici5tly high av]age4 ,f ^! data x foll[s t if an am\nt ( gr\nd-wat] equal to five p]c5t4 ( ! volume ( ! lava ent]$ ! lava & 0 br\ght up to its temp]ature & !n dis*>g$1 ! temp]ature ( ! :ole mass w\ld be l[]$ #eej ,fahr4 ,x is !re=e evid5t t only a small p]c5tage ( surface-wat] c pass ?r\gh ! lava consi/5tly ) its cont9u$ fluidity4 ,m4 ,f\qu e/imat$ t ! dis*>ge ( /eam f a m]ely p>asitic cone ( ,etna dur+ #ajj days 0 equal to #b1ajj1jjj cubic met]s ( wat]4 ,if ?is 7 gr\nd-wat]1 & ! lava f :i* x issu$ _h an excess ( #ejj ,fahr4 above ! fusion-po9t1 ! =mation ( ?is /eam w\ld congeal a column #djj feet 9 diamet] & #cjjj feet deep 9 ! "t giv54 ,if ?is case is typical1 & if ,f\qu's e/imate is n greatly exagg]at$ or v exceptional1 ! view t any l>ge portion ( ! /eam f volcanoes comes f surface-wat]s seems to be incompatible ) ! p]si/5ce ( ebullition & explosion :i* _m ( !m exhibit4 ,/romboli has be5 9 con/ant eruption z f> back z ! hi/ory ( ! region runs4 ,x is n[ explod+ e ?ree to t5 m9utes1 & yet ! mass ( lava seems to be small & its outfl[ inconsid]able4 ,is x possible t a curr5t ( /eam1 giv5 out ) ?is activity = s long a p]iod1 0 d]iv$ f adjac5t gr\nd-wat]s1 & has n yet solidifi$ ! lava8 ,! problem takes on a v diff]5t aspect if ! /eam1 or at lea/ "s l>ge "p ( x1 rises f great dep?s & br+s !nce an excess ( heat4 ,x !n becomes an ag5cy = ! ma9t5ance ( ! liquidity ( ! lava1 = giv+ x convective motion1 & = promot+ explosive action1 s long z x cont9ues to rise4 ,= ^! & o!r reasons ! balance ( pres5t evid5ce seems to u to favor ! view t mo/ ( ! /eam & o!r gases come ) ! lava f its orig9al s\rce deep 9 ! e>?4 ,ref]5ces on vulcanism4--,g4 ,p4 ,scrope1 ,volcanoes1 ,london1 #ahgb4 ,r4 ,mallet1 on ,volcanic ,en]gy1 ,phil4 ,trans41 #ahgc4 ,c4 ,d>w91 ,geological ,obs]vations on ,volcanic ,isl&s1 ,london1 #ahgf4 ,e4 ,rey]1 ,beitrag zur ,physik d] ,eruption51 ,vi5na1 #ahgg2 ,!oretis*e ,geologie1 #ahhh4 ,f\qu1 ,santor9 et ses ruptions1 ,p>is1 #ahgi1 ,s>toris von ,walt]%aus5 & ,a4 von ,lasaulx1 ,d] ,aetna1 ,leipzig1 #ahhj4 ,c4 ,e4 ,dutton1 ,geology ( ! ,high ,plateaus ( ,utah1 ,u4 ,s4 ,geog4 & ,geol4 ,surv41 #ahhj2 ,! ,hawaiian ,volcanoes1 ,f\r? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhc4 ,judd1 ,volcanoes1 #ahha2 ,! ,eruption ( ,krakatoa 7,com4 ( ! ,roy4 ,soc471 #ahhh4 ,j4 ,d4 ,dana1 ,*>act]i/ics ( ,volcanoes1 #ahij4 ,h4 ,j4 ,john/on-,lavis1 ,! ,s\? ,italian ,volcanoes1 ,naples1 #ahia4 ,e4 ,hull1 ,volcanoes1 ,pa/ & ,pres5t1 #ahib4 ,milne & ,burton1 ,! ,volcanoes ( ,japan1 #ahib4 ,j4 ,p4 ,idd+s1 ,! ,orig9 ( ,igne\s ,rocks1 ,bull4 ,phil4 ,soc41 ,wa%+ton1 ,vol4 ,,xii1 #ahib4 ,a4 ,c4 ,lane1 ,geologic ,activity ( ! ,e>?'s ,orig9ally ,absorb$ ,gases1 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,v1 #ahid4 ,a4 ,geikie1 ,anci5t ,volcanoes ( ,great ,brita91 ,london1 #ahig4 ,i4 ,c4 ,russell1 ,volcanoes ( ,nor? ,am]ica1 #ahig4 ,t4 ,g4 ,bonney1 ,volcanoes1 ,_! ,/ructure & ,significance1 ,new ,york 7& ,london71 #ahii4 ,f4 ,miron1 tude des ,phnomnes ,volcaniques1 ,p>is1 #aijc4 ,g4 ,c4 ,curtis1 ,second>y ,ph5om5a ( ! ,we/ ,indian ,volcanic ,eruptions ( #aijb1 ,j\r4 ,geol41 ,vol4 ,,xi1 ,no4 #b1 #aijc4 ,a4 ,heilpr91 ,mont ,pele & ! ,trag$y ( ,m>t9ique1 ,philadelphia 7& ,london71 #aijc4 ,rob]t ,t4 ,hill1 ,report on ! ,volcanic ,di/urbances 9 ! ,we/ ,indies1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #g1 #aijb4 ,i4 ,c4 ,russell1 ,! ,rec5t ,volcanic ,eruptions 9 ! ,we/ ,indies1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #g1 #aijb2 ,volcanic ,eruptions on ,m>t9ique & ,/4 ,v9c5t1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #ab1 #aijb4 ,j4 ,s4 ,dill]1 ,volcanic ,rocks ( ,m>t9ique & ,/4 ,v9c5t1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #g1 #aijb4 ,w4 ,f4 ,hillebr&1 ,*emical ,discussion ( ,analyses ( ,volcanic ,ejecta f ,m>t9ique & ,/4 ,v9c5t1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #g1 #aijb4 ,e4 ,o4 ,hovey1 ,! ,eruptions ( ,la ,s\frire1 ,/4 ,v9c5t1 9 ,may1 #aijb1 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 ,no4 #ab1 #aijb4 ,,*apt] ,,xi4 ,,! ,,geologic ,,functions ,,( ,,life4 ,i4 ,,! ,,di/9ctive ,,features ,,( ,,organic ,,processes4 ,!re is no reason to suppose t life processes1 z we "k !m1 7 9 op]ation 9 ! e>lie/ /ages ( ! e>?'s hi/ory4 ,!y 7 introduc$ & develop$ gradually dur+ its progress4 ,) life !re came into ! processes ( ! e>?'s developm5t ?ree di/9ctive factors3 ,a4 ,c]ta9 *emical actions giv+ rise to comp\nds t are n kn[n to occur indep5d5tly ( life4 ,b4 ,c]ta9 modes ( aggregation ( mat]ial1 & c]ta9 k9ds ( bodily movem5ts1 n kn[n except 9 association ) life4 ,c4 ,! m5tal elem5t1 "u ! direction ( :i* c]ta9 new processes 7 inaugurat$1 & c]ta9 previ\s processes 7 modifi$ & controll$4 ,a4 ,! ,*emical ,"w ( ,life4 ,! peculi> *emical ph5om5a connect$ ) life *iefly conc]n ! c>bon comp\nds4 ,9 ! inorganic _w ! c>bon comp\nds are few & simple4 ,9 ! organic _w !y become extremely num]\s & complicat$4 ,^! comp\nds are v un/able1 = ! great] "p1 & _! p>tial decomposition gives rise to _m additional comp\nds4 ,"s ( ! true organic comp\nds & "s ( _! decomposition products h ! p[] ( comb9+ ) inorganic sub/ances1 & s produce an additional s]ies ( semi-organic comb9ations4 ,! total numb] ( ! comp\nds ?us directly & indirectly connect$ ) life greatly exce$s t ( all inorganic comp\nds4 ,_! mass1 h[ev]1 is v greatly inf]ior4 ,life mat]ial *iefly atmosph]ic4--,9 ! build+ up ( ! organic comp\nds1 a necess>y /ep is ! decomposition ( c]ta9 inorganic comp\nds4 ,! *ief ( ^! is ! c>bon dioxide ( ! atmosph]e & hydrosph]e1 ! decomposition ( :i* furni%es ! c>bon ne$$ = ! organic comp\nds4 ,on ?is acc\nt c>bon dioxide may be reg>d$ z 9 "s s5se ! basal mat]ial or ! fundam5tal food ( ! organic k+dom1 & h5ce x plays a radical rle 9 ! life-hi/ory ( ! e>?4 ,wat]1 & ! con/itu5ts ( wat]1 oxyg5 & hydrog51 play a l>g] "p quantitatively1 b a less di/9ctive "p4 ,nitrog5 is also an ess5tial elem5t1 & usually /&s next to c>bon1 oxyg51 & hydrog5 9 quantity4 ,^!1 x w be not$1 are all atmosph]ic con/itu5ts1 & ! mat]ial ( life is1 !re=e1 dom9antly atmosph]ic4 ,?is is ev5 true ( aquatic life1 = x lives l>gely on ! atmosph]ic con/itu5ts dissolv$ 9 ! wat]4 ,! function ( life1 consid]$ f ! mat]ial po9t ( view1 is n only fundam5tally conc]n$ ) ! atmosph]e1 & intimately dep5d5t on its conditions1 b its mo/ important mat]ial effects appe> to lie 9 its modification ( ! con/itution ( ! atmosph]e4 ,! non-atmosph]ic factors4--,! atmosph]ic con/itu5ts are n1 h[ev]1 ! only elem5ts intimately connect$ ) ! life function4 ,comp\nds ( sulphur1 phosphorus1 potassium1 sodium1 *lor9e1 iron1 calcium1 magnesium1 silicon1 & o!r elem5ts are m or less ess5tial to ! life ( _m organisms1 or are employ$ by !m = _! skeletons1 cov]+s1 etc4 ,incid5tally1 ne>ly all ! common elem5ts become intimately relat$ to liv+ organisms ei!r 9 ! relations ( active elem5ts 9 _! physiological functions1 or ( passive elem5ts 9 _! /ructure or 9 _! auxili>y p>ts4 ,?ree ,classes ( ,effects4 ,out ( life processes gr[ ?ree r di/9ct classes ( results3 7#a7 *anges 9 ! am\nts & proportions ( ! con/itu5ts ( ! atmosph]e &1 to "s slight ext5t1 ( ! hydrosph]e & li?osph]e2 7#b7 aid or h9drance to inorganic processes1 su* z dis9tegration1 erosion1 & deposition2 & 7#c7 di/9ctive products1 ei!r 7a7 ( organic matt] t w\ld n h come into ! exi/+ comb9ation b = life1 su* z peat1 lignite1 amb]1 etc41 or 7b7 ( special =ms ( inorganic matt] t w\ld n h aris5 b = life1 su* z coral deposits1 %ell-m>l1 diatom ooze1 etc4 7#a7 ,*anges 9 ! composition ( ! atmosph]e4 ,! succession ( modifications :i* ! atmosph]e has und]gone f "t to "t ?r\gh ! action ( life w be discuss$ z ! e>?'s hi/ory is foll[$ 9 ! second volume4 ,x may suffice "h to note briefly ! *ief ways 9 :i* ! atmosph]e has probably be5 modifi$ by ! ag5cy ( life1 n only z reg>ds its quantity b also z reg>ds ! proportions ( its con/itu5ts4 ,! consumption & re/oration ( c>bon dioxide4--,z ! fundam5tal food ( ! organic _w1 c>bon dioxide has suff]$ enorm\s consumption 9 ! c\rse ( ! geological ages1 & is n[ r$uc$ to ! v small proportion ( 4#jjjd or 4#jjjc ( ! :ole4 ,at ! outset x 0 probably "o ( ! mo/ abundant con/itu5ts2 possibly ev5 ! *ief "o4 ,x has be5 p>tially re/or$1 concurr5tly ) its consumption1 by animal respiration1 by c]ta9 classes ( plant action1 & by combu/ion & o!r =ms ( inorganic comb9ation4 ,?is re/orative action has be5 incomplete at all kn[n /ages ( ! e>?'s hi/ory1 & h5ce !re has be5 con/ant loss ( c>bon dioxide4 ,! inorganic processes :i* h also pr(\ndly affect$ bo? ! consumption & re/oration ( c>bon dioxide are "h neglect$ & discuss$ else:]e4 ,! free+ & consumption ( oxyg54--,! oxyg5 ( ! atmosph]e is actively consum$ by animals & by plants1 b on ! o!r h&1 x is set free abundantly by gre5 plants1 & h5ce its am\nt has probably fluctuat$ f "t to "t accord+ to ! /ate ( balance betwe5 ! organic processes ( its production1 & ^? ( its consumption4 ,! consumption ( oxyg5 by organic processes is1 h[ev]1 little m ?an a rev]sal ( ! previ\s process by :i* x 0 set free2 = in/ance1 gre5 plants 9 =m+ _! food set free ! oxyg5 ( ! c>bon dioxide us$ = ! purpose4 ,:5 ! organic sub/ance s =m$ is ultimately consum$ ?r\gh plant or animal action or by inorganic means1 an equival5t am\nt ( oxyg5 reunites ) ! c>bon to aga9 =m c>bon dioxide4 ,& s if ! :ole ( ! organic matt] is return$ to ! inorganic /ate1 no m oxyg5 is consum$ ?an _h be5 be=e set free 9 ! process ( =m+ ! organic matt]4 ,b1 z a matt] ( fact1 a l>ge am\nt ( organic matt] has n gone back completely to ! inorganic /ate1 & ?is residue con/itutes a factor ( no small importance 9 ! geological record4 ,! organic residue4--,!re is a c]ta9 portion ( vegetation t is n consum$ by animals or by o!r plants1 & t escapes combu/ion & all k9ds ( ord9>y decay1 & ?is con/itutes a "p ( ! organic residue4 ,animals nev] completely oxidize all ! organic matt] !y take into _! sy/ems2 _! bodies nev] entirely consume !mselves4 ,a l /atem5t may be made respect+ ^? plants t fe$ on organic matt]4 ,t :i* animals & plants leave unoxidiz$ is inde$ m or less prey$ ^u by o!r animals & plants1 & relatively little escapes f9al reoxidation1 b !re is a remnant1 & ?is con/itutes ano!r "p ( ! organic residue4 ,! m conspicu\s =ms ( ! organic residue are f\nd 9 ! mucks1 peats1 lignites1 coals1 organic oils1 & gases1 b 9 addition !re is n a little dissem9at$ organic matt] 9 ne>ly all ! s$im5t>y rocks2 9 ! aggregate1 ?is probably am\nts to m ?an ! di/9ct organic deposits4 ,! mean+ ( ! organic residue4--,all ! unoxidiz$1 or incompletely oxidiz$1 c>bon 9 ! organic residue implies t oxyg5 has previ\sly be5 sep>at$ f ?is residual c>bon by plants & giv5 to ! atmosph]e1 & h5ce has be5 a s\rce ( atmosph]ic enri*m5t 9 oxyg54 ,! am\nt ?us contribut$ is equal to t :i* is requir$ to re/ore ! residual c>bon to its orig9al /ate ( oxidation4 ,s1 9 a simil> way1 ! unoxidiz$ hydrog5 9 ! organic hydroc>bons & l comp\nds implies t oxyg5 has be5 sep>at$ f ! hydrog5 ( wat] & giv5 to ! atmosph]e1 & h5ce ?is also is a s\rce ( atmosph]ic enri*m5t 9 oxyg54 ,x seems safe1 !re=e1 to conclude t ! action ( life1 tak5 z a :ole1 has increas$ ! free oxyg5 ( ! atmosph]e4 ,:ile n "h "u consid]ation1 x is n to be =gott5 t inorganic processes involv+ ! same atmosph]ic con/itu5ts h be5 9 op]ation concurr5tly ) ! organic processes1 & t !y h also affect$ ! am\nts & proportions ( ! atmosph]ic con/itu5ts4 ,rocks h be5 oxidiz$ 9 great] or less measure at ! exp5se ( ! atmosph]ic oxyg51 & h5ce :5 ! total atmosph]ic problem is consid]$1 !re arises ! "q :e!r ! am\nt ( oxyg5 9 ! atmosph]e has be5 increas$ or dim9i%$ dur+ geological hi/ory1 :5 ! balance is /ruck betwe5 ! inorganic & ! organic actions4 ,! probabilities seem to u to /rongly favor ! view t organic action has prepond]at$1 & t ! oxyg5 has be5 increas$ beyond its primitive am\nt1 b t x has fluctuat$ dur+ kn[n geological hi/ory4 ,! reasons = ?is view w appe> 9 ! hi/orical *apt]s4 ,! dis9tegration ( ! cry/all9e rocks & ! solution ( lime/one h consum$ mu* c>bon dioxide1 & ?is is to be add$ to ! loss ?r\gh organic action4 ,on ! o!r h&1 !re are inorganic processes t supply c>bon dioxide1 & h5ce :5 ! l>g] problem ( ! atmosph]e is rais$1 ! factors become s complicat$ t _! consid]ation is be/ def]r$ to ! hi/orical *apt]s4 ,?is pass+ ref]5ce may /& u 9 good "p le/ we =get1 = ! mom5t1 ! inorganic factors 9 ! atmosph]ic problem4 ,! m in]t factor4--,nitrog5 9 ! free /ate is relatively in]t *emically1 & x does n appe> t x c be us$ directly by ! high] plants & animals 9 appreciable am\nts4 ,c]ta9 bact]ia1 & p]haps c]ta9 alg#bhh & o!r l[ =ms ( plants1 h ! p[] ( us+ free nitrog51 & ?is is a pr9cipal way 9 :i* x is put )9 ! rea* ( high] plants4 ,nitrog5 is also comb9$ 9 small quantity 9 ! atmosph]e by electric action1 & ?us made available = plants4 ,on acc\nt ( ! in]tness ( nitrog5 & ( ! relatively limit$ am\nt requir$ = organic purposes1 ! nitrog5 ( ! atmosph]e has be5 less consum$ ?an ! c>bon dioxide4 ,besides ?is1 ! nitrog5 comp\nds are v decomposable1 & are v g5]ally & completely return$ to _! orig9al /ate4 ,deposits ( nitrates or o!r nitrog5\s comp\nds are relatively r>e4 ,x is obvi\s t if !re is any consid]able s\rce ( supply concurr5t ) ?is slight loss1 ! am\nt ( nitrog5 9 ! atmosph]e mu/ h be5 increas+4 ,we h se5 t volcanoes give =? consid]able quantities ( nitrog51 & t ?is may be a real addition to ! atmosph]e1 & n m]ely a return ( ! atmosph]ic nitrog5 t _h be5 c>ri$ d[n previ\sly by und]gr\nd-wat]4 ,x has also be5 not$ t cry/all9e rocks conta9 occlud$ nitrog51 :i* is d\btless fre$ by _! dis9tegration4 ,x is1 !re=e1 n improbable t ! nitrog5 ( ! atmosph]e has be5 increas+1 bo? actually & relatively4 ,probable fluctuations ( atmosph]ic composition4--,) ?is g5]al sket* ( ! int]play ( ! atmosph]ic elem5ts "u organic influ5ce1 we are prep>$ = ! fur!r conception t if "o or ano!r ( ^! actions 0 relatively m vigor\s ?an usual = a p]iod1 x w\ld br+ ab\t a v>iation 9 ! proportions ( ! atmosph]ic con/itu5ts4 ,if1 = example1 vegetation fl\ri%$ luxuriantly = a long p]iod1 b 0 measurably protect$ f ! organisms t prey$ ^u x & f inorganic decomposition1 z by fall+ into wat] or by prompt burial "u s$im5t1 ! atmosph]e might be gr[+ ri*] 9 oxyg54 ,if1 on ! o!r h&1 vegetation 7 be+ relatively r$uc$1 z p]haps x is be+ r$uc$ n[ by man1 & if previ\s organic products 7 be+ reoxidiz$ at an unusual rate1 z !y are n[ 9 ! burn+ ( timb]1 coal1 natural oil & gas1 ! c>bon dioxide ( ! atmosph]e might be relatively increas+1 :ile ! oxyg5 might be relatively dim9i%+4 ,! possible fluctuations ( ! atmosph]e z ! result ( organic action are1 !re=e1 matt]s ( vital importance1 & invite att5tion 9 ! hi/orical /udy ( ! e>? & 9 ! outlook into its future4 ,! climatic effects ( organic action4--,int]e/ does n1 h[ev]1 re/ at ?is po9t4 ,! rese>*es ( physici/s h made x probable1 if !y h n altoge!r demon/rat$1 t ! composition ( ! atmosph]e has mu* to d ) ! climatic conditions at ! surface ( ! e>?4 ,! atmosph]e blankets ! e>? & equalizes its temp]ature4 ,act+ z a scre51 x subdues 9 "s measure ! int5sity ( ! sun's rays by day1 :ile x ret>ds ! radiation ( ! e>?'s acquir$ heat at night4 ,?is is 9 "s measure ! function ( all ! con/itu5ts ( ! atmosph]e1 b by no means ( all equally4 ,! oxyg5 & nitrog5 are relatively dia!rm\s1 lett+ ! sun's rays pass 9 freely1 & ! e>?'s rays pass out freely2 b c>bon dioxide & ! vapor ( wat] are mu* less dia!rm\s1 p>ticul>ly to rays ( l[ int5sity1 su* z are ?r[n out by non-lum9\s bodies l ! e>?4 ,x foll[s t :ile ! sol> rays come 9 r freely & heat ! surface ( ! e>?1 ! d>k rays :i* ! e>? radiates back are measurably arre/$ by ! c>bon dioxide & vapor ( wat]1 & s]ve to keep ! air w>m4 ,! influ5ce ( ! vapor ( wat] is vividly %[n 9 ! diff]5t degrees to :i* cool+ takes place at night 9 a dry & 9 a moi/ atmosph]e1 respectively1 :]e o!r conditions are ! same4 ,ice is said to =m at night 9 des]t regions :]e ! air is extremely dry1 ev5 )9 ! tropics1 :ile 9 humid regions ( ! same latitude & altitude oppressively hot nights are common4 ,! influ5ce ( ! c>bon dioxide is n ?us famili>ly demon/rat$1 s9ce its am\nt v>ies b slightly 9 diff]5t localities1 b physical exp]im5t indicates t x has a simil> function4 ,if ! am\nt ( c>bon dioxide 9 ! atmosph]e v>ies f age to age1 ! climate ( ! e>? mu/ app>5tly v>y accord+ly1 & on ?is is built "o ( ! hypo!ses ( climatic v>iation subsequ5tly to be consid]$4 ,we %all f9d t !re h be5 great *anges 9 ! climate ( ! e>? dur+ its hi/ory4 ,!re is good evid5ce ( =m] glaciation1 n only 9 ! nor!rn ,unit$ ,/ates & 9 ,engl&1 ,g]many1 & c5tral ,russia1 b 9 ,india1 ,au/ralia1 & ,s\? ,africa4 ,at o!r times1 figs & magnolias grew 9 ,gre5l& & ,spitzb]g51 & corals fl\ri%$ 9 ! ,arctic seas4 ,!re is good evid5ce ( arid p]iods :]e humidity n[ prevails1 & ( humid p]iods :]e aridity n[ prevails4 ,x is n assum$ t ! influ5ce ( organic action on ! atmosph]e has be5 ! sole1 or p]haps ev5 ! ma91 cause ( ^! great climatic *anges1 b x is believ$ t x has be5 an important contribut+ factor4 ,x is ev5 possible t ! climate ( ! future is mu* dep5d5t on ! ag5cy ( man1 z impli$ above1 h[ev] little gr\nd !re may be to suppose t he w1 ) altrui/ic purpose1 control 8 action ) a view to its be>+ on ! g5]ations t may live t5s ( ?\s&s ( ye>s h5ce4 7#b7 ,aid & h9drance to inorganic action4 ,! promotion ( dis9tegration4--,:ile ! influ5ce ( organic action on ! li?osph]e is q sup]ficial1 & f> less radical ?an t on ! atmosph]e1 x is /ill important4 ,plants promote bo? dis9tegration & disaggregation "u c]ta9 conditions1 & h9d] !m "u o!rs1 z already set =?4 ,*emical action ( a decompos+ & solv5t nature takes place 9 connection ) ! roots ( plants1 :ile _! gr[? sometimes r5ds rocks into ^: crevices !y h ins9uat$ !mselves4 ,! acids & o!r products ( organic gr[? & ( organic decomposition attack "s ( ! con/itu5ts ( ! rocks & contribute to _! solution & dis9tegration4 ,on ! o!r h&1 organic matt] entrapp$ 9 ! s$im5ts1 & s introduc$ into ! /rata at v>i\s dep?s1 (t5 acts z a r$uc+ ag5cy1 caus+ ! deposit ( sub/ances c>ri$ 9 solution 9 ! und]gr\nd-wat]s4 ,ores are sometimes ?us =m$1 z expla9$ 9 ! discussion ( ore-deposits 7p4 #dgf74 ,organic action on ! :ole promotes solution & dis9tegration at ! surface1 & prep>es ! way = deposition bel[4 ,protection aga9/ erosion4--,ano!r important function ( vegetation is ! protection ( ! l& surface aga9/ erosion1 z already not$ 9 ! discussion ( erosion4 ,a mantle ( grass1 especially if x =ms a turf1 or a c>pet ( leaves protect$ by bu% & =e/1 greatly ret>ds surface wa%4 ,x does ?is n only because x directly cov]s ! soil1 b because x holds back ! run-(f & t5ds to prev5t ^? viol5t floods :i* give to erosion its greate/ int5sity4 ,!re is a m>k$ diff]5ce betwe5 ! erosive "w :i* a giv5 am\nt ( wat] w d if1 9 ! "o case1 x runs (f gradually1 & 9 ! o!r1 precipitately4 ,by way ( (fset1 x is to be not$ t ! dis9tegrat+ action ( vegetation prep>es ! rock mat]ial = easy erosion1 & to ?is ext5t helps 9 its removal by ! dra9age2 b on ! av]age ?is is greatly ov]balanc$ by ! protection af=d$ by ! vegetal cov]+1 ?\gh ?is is n true 9 e in/ance4 ,! influ5ce ( l& vegetation on ! "* ( ! s$im5ts4--,! pres5ce or abs5ce ( a vegetal cov]+ influ5ces ! k9d ( deposit :i* is d]iv$ f ! l&1 p>ticul>ly if ! surface be occupi$ by cry/all9e rocks4 ,if ! surface be well clo!d ) vegetation1 ! cry/als ( ! complex silicates1 su* z ! feldsp>s1 micas1 & f]romagnesian m9]als1 are usually dis9tegrat$ into clayey products be=e !y are remov$1 s t1 :5 borne away & deposit$1 ! result is common %ale4 ,concurr5tly1 ! relatively undecomposable qu>tz-gra9s are r\nd$ into s&1 & deposit$ z common qu>tzose s&/one1 :ile ! calc>e\s mat]ial is borne away 9 solution & deposit$ z lime/one4 ,b if ! surface be b>e ( vegetation1 ! cry/all9e rocks are usually disaggregat$ be=e !y are decompos$1 = de/ructive action works be/ at ! junctions ( cry/als1 & along cleavage l9es1 & h5ce ! cry/als are usually sep>at$ f "o ano!r be=e !y are fully decompos$4 ,9 ! abs5ce ( a cov]+ to hold !m 9 place until !y are decompos$1 !y are apt to be wa%$ away1 & ! result+ deposit consi/s 9 consid]able "p ( gra9s ( feldsp>1 mica1 hornbl5de1 & o!r m9]als1 :i* d n usually occur 9 well-decompos$ s$im5ts4 ,! deposits are1 !re=e1 ( ! nature ( arkose1 if ! orig9al rocks are granitic1 or ( ! nature ( wacke1 z ! t]m is us$ 9 ?is book1 if !y are ( ! basic type4 ,on ?is is bas$ ! inf]5ce t a vegetal cov]+ ( ! l& ext5d$ z f> back 9 ! hi/ory ( ! e>? z clay %ales1 qu>tzose s&/ones1 & lime/ones =m ! prevail+ s$im5ts4 7#c7 ,di/9ctive deposits4 ,organic rocks4--,9 ! *apt] on ! orig9 & desc5t ( rocks1 a gr\p ( rocks =m$ directly f organic matt] is recogniz$ & describ$4 ,! *ief ( ^! are peat1 lignite1 bitum9\s coal1 an?racite1 & graphite4 ,x is ! belief ( _m geologi/s t natural gases1 oils1 & asphalts are also ma9ly d]iv$ f animal & vegetal rema9s4 ,an alt]native view1 advocat$ by ,m5delejeff & ,moissan1 assigns ! oils1 gases1 etc41 9 "p at lea/1 to deep-seat$ c>bides to :i* wat] has ga9$ access & develop$ hydroc>bons1 aft] ! analogy ( acetyl5e4#bhi ,:atev] may be ! tru? relative to inorganic action1 x is cle> f geological conditions t "s ( ! natural gases & oils are organic products4 ,besides ! m common organic deposits1 !re is a long li/ ( m9or products1 among :i* are amb]1 copalite1 p>aff9e1 ozoc]ite1 camph5e1 etc4 ,guano & coprolites repres5t ! excrem5titi\s class4 ,inorganic rocks due to life4--,besides ^! deposits ( organic matt]1 or ( its decomposition products1 !re is a l>ge class =m$ f ! inorganic matt] t s]v$ auxili>y functions 9 ! economy ( life1 su* z %ells1 skeletons1 etc4 ,= ! great] "p ^! are compos$ ( calcium c>bonate1 & give rise to lime/ones1 m>ls1 *alk1 etc4 ,n a few1 h[ev]1 are silici\s1 & give rise to fl9ts1 *]ts1 & silici\s e>?s4 ,"s are =m$ ( calcium phosphate1 & a few ( o!r inorganic mat]ial4 ,! deposits =m$ 9 ^! ways h be5 def9$ 9 ! *apt] on rocks4 ,fossils4 ,! t]m fossil is us$ s compreh5sively z to include n only ! rema9s ( plants & animals !mselves1 b _! tracks1 impressions1 ca/s1 replacem5ts1 & all o!r di/9ct traces4 ,x also embraces ne/s1 bor+s1 implem5ts1 & o!r di/9ctive products4 ,^! ent] into ! =mation ( ! two classes ( rocks j consid]$1 b !y h an indep5d5t function4 ,!y con/itute ! specific record ( life1 & _! /udy n only reveals mu* ( ! pa/ hi/ory ( plants & animals1 b furni%es "o ( ! mo/ important means by :i* ! ages ( =mations are det]m9$4 ,9 ! e>ly developm5t ( ! sci5ce x 0 f\nd t ! upp]mo/ & h5ce ! late/ b$s ( rock conta9 fossil =ms ei!r id5tical ) ^? n[ liv+1 or closely simil> to !m2 t b$s bel[ ^! be> life relics t dep>t some:at m f ! liv+ =ms1 & are some:at less highly develop$2 t b$s /ill l[] be> fossils t dep>t /ill m f ! liv+ types1 & are m primitive 9 g5]al1 & s on d[n z f> z fossils are f\nd4 ,! g5]al ord] ( life succession det]m9$ by /ratigraphy4--,?us x appe>$ f ! evid5ce ( ! /rata t !re 0 a g5]al ord] ( life succession4 ,x 0 also f\nd t ?is 01 9 its ma9 features1 ! same = all ! cont95ts4 ,by cont9u$ & close /udies1 ! p>ticul>s ( ! succession 7 work$ out m & m fully1 & ! "w is /ill be+ pu%$ =w>d to great] & great] degrees ( ref9em5t4 ,at ! same "t1 x 0 f\nd t !re 7 diff]5t faunas & floras 9 diff]5t p>ts ( ! _w 9 pa/ times1 mu* z !re are n[2 t !re 7 %ift+s & migrations z n[2 t giv5 species 7 increas+ 9 "s regions & dy+ out 9 o!rs1 & t innum]able v>iations & complications ent]$ into ! evolution & di/ribution ( ! life =ms4 ,b "u & ?r\gh all ^! !re run a suffici5t numb] ( common features to %[ beyond reasonable "q ! ord] ( succession ( life4 ,?r\gh\t all ?is /udy1 ! *ief guide 0 ! actual ord] 9 :i* ! fossils 7 f\nd 9 ! succession ( /rata1 because !re is no evid5ce s conclusive ( ! ord] ( ev5ts z ! sup]position ( ! s$im5t>y b$s :5 !y are normal & undi/urb$4 ,by ! /udy ( ! fossils 9 ! successive b$s1 x 0 f\nd t !re 0 a m or less progressive evolution ( plants & animals br\ght ab\t by modifications ( _! =ms1 & t ^! modifications assi/$ 9 det]m9+ ! ord] ( succession :5 ! evid5ce ( ! /rata 0 defective2 & s ! biological & /ratigraphical factors react$ helpfully on ea* o!r4 ,fossils z means ( correlation4--,:ile /ratigraphy 0 ?us1 9 ! e>lie/ /ages1 ! ma9 reliance 9 det]m9+ ! ord] ( ev5ts1 & biology 0 ! *ief ga9]1 9 ! end /ratigraphy receiv$ ample comp5sation1 if inde$ x did n become ! great] b5efici>y2 = at no kn[n & accessible place is !re a complete succession ( s$im5t>y b$s4 ,!re are great s]ies "h & !re1 b _! connections ) "o ano!r are m or less conceal$ by surface =mations or wat]-bodies4 ,s also at _m places ! /ratifi$ s]ies has be5 brok5 up by de=mation1 or cut away by erosion4 ,h5ce !re 0 ne$ = "s reliable means ( mat*+ ! b$s ( sep>at$ s]ies1 & ( mak+ up a complete ideal s]ies4 ,?is means is f\nd 9 ! fossils !y conta94 ,:ile ! v>iations ( ! faunas & floras 9 diff]5t regions1 & _! migrations1 introduce "s m9or difficulties1 ! relations ( ! fossilif]\s b$s ( "o region to ^? ( ano!r c be det]m9$ ) great satisfaction1 & (t5 ) great precision4 ,?is is p>ticul>ly s :5 abundant float+ or free-swimm+ species liv$ 9 ! seas & 7 freely fossiliz$1 = !y 7 deposit$ on ! coa/s ( all ! cont95ts at practically ! same "t1 & no unc]ta9ties f migration or local diff]5ces 9 rate ( evolution int]v5$ to ?r[ d\bt ^u ! correlation4 ,)\t ! aid ( fossils1 ! correlation ( ! deposits on ! sep>ate cont95ts w\ld be att5d$ ) grave ob/acles & mu* unc]ta9ty1 if n ) q prohibitive difficulties4 ,b4 ,special ,modes ( ,aggregation & ( ,movem5t4 ,inorganic solid matt] is *iefly cry/alloidal2 organic matt] is *iefly colloidal2 b !re are colloidal /ates ( inorganic matt] & !re are cry/alloids among ! organic products4 ,9 ! inorganic _w1 solids v g5]ally t5d to organize 9 ! =m ( cry/als2 9 ! organic _w1 !y z g5]ally t5d to organize 9 ! =m ( cells4 ,nei!r t5d5cy is complete or exclusive1 b ea* is dom9ant 9 its own sph]e4 ,/ill m di/9ctive ?an ! =mation ( cells is ! gr[? ( complex organiz$ bodies1 ! diff]5tiat$ memb]s ( :i* p]=m special functions = "o ano!r1 & are mutually dep5d5t on "o ano!r4 ,?is is a pr(\nd dep>ture f ! habitual modes ( ! inorganic _w4 ,/ill m s is ! p[] ( volunt>y motion 9 m or less disreg>d ( outside physical influ5ces4 ,?r\gh ?is p[]1 di/ribution may take place contr>y to curr5t & w9d1 & to gravitation itself4 ,f ! view-po9t ( pa/ geologic transportation1 ?is is p]haps m s+ul> ?an important1 = no great mass ( matt] has be5 transport$ contr>y to ! influ5ces ( gravity1 w9d1 & curr5t1 by ! ex]cise ( ?is peculi> p[] ( animals1 b x is n )\t geologic importance 9 ! migrations & 9 ! r$i/ributions ( organic influ5ces t arise f migrations4 ,:5 ! influ5ce ( man is includ$1 ! geologic effects require consid]ation1 b "h ! ?ird di/9ctive factor1 ! m5tal elem5t1 comes into effective play1 & we pass to its consid]ation4 ,c4 ,! ,m5tal ,elem5t4 ,curr5t op9ion does n recognize a m5tal elem5t z resid+ 9 ! plant _w1 & x is divid$ z to ! degree ( its developm5t 9 ! l[] animal k+dom1 b its influ5tial pres5ce 9 ! high] animal ord]s & 9 man is beyond legitimate "q4 ,two phases are to be recogniz$3 7#a7 ! mat]ial "w done "u ! /imulus & direction ( m5tal impulses1 z1 = example1 excavations1 transportations1 *anges ( dra9age1 removal ( =e/s1 cultivation ( soil1 etc41 & 7#b7 ! intellectual "w ( ! faculties !mselves irrespective ( mat]ial *anges4 ,9 "o view1 geology is a purely mat]ial sci5ce conc]n$ solely ) ! =mation ( ! e>? & ) ! physical developm5t & relations ( its inhabitants4 ,9 ano!r1 geology is a compreh5sive hi/orical sci5ce conc]n$ ) e phase ( ! _w's hi/ory1 & c]ta9ly n lea/ ) ! high] =ms ( life developm5t1 ) _! psy*ological1 sociological1 & o!r phases ( m5tal atta9m5ts1 s9ce ^! are ! highe/ output ( ! e>?'s evolution4 ,! latt] seems to u ! m compreh5sive view4 7#a7 ,! mat]ial effects ( ! m5tal elem5t4--,lyell long s9ce urg$ t ! direct "w ( man 9 *ang+ ! face ( ! e>? 0 slight comp>$ ) t ( ! contemporane\s inorganic ag5cies4 ,he call$ att5tion to ! relative insignificance ( ! qu>ries1 pits1 cell>s1 & o!r excavations ( man1 comp>$ ) ! "w ( /reams1 waves1 & o!r inorganic ag5cies4 ,!re is ju/ness 9 ?is view1 b x ne$s qualification4 ,x is to be obs]v$ t ! m5tal era has b j begun1 & t its effects are increas+ ) a rapidity q ph5om5al :5 measur$ by ! sl[ pace ( mo/ geologic ev5ts4 ,! excavations & transportations ( mat]ial to-day %[ an enorm\s advance on ^? ( ,lyell's day1 :i* 01 geologically speak+1 b a mom5t ago4 ,! mile-tons ( indu/rial freightage 9 ! ,mississippi bas9 are to-day n :olly incomp>able ) ! dra9age transportation ( ! same area a c5tury ago4 ,a c5tury ago is nam$1 because ! surface 0 !n cov]$ ) natural vegetation1 & ! normal effect ( surface erosion1 indep5d5t ( man1 0 !n exp]i5c$4 ,at pres5t ! indirect effects ( man's action are m+l$ ) ^? ( natural processes1 & ^! indirect effects are probably mu* m important ?an ! direct ones4 ,! removal ( ! native vegetation & ! cultivation ( ! soil expose ! surface to wa% to a degree f> beyond t preval5t :5 ! surface 0 prairie sod1 or leaf-c>pet$ =e/1 & d5udation & transportation h be5 greatly multipli$ 9 consequ5ce4 ,n only has ?is cultivation increas$ ! exposure to erosion1 b1 by increas+ ! rate ( run-(f1 x has add$ to ! erosive p[] ( ! /reams4 ,! dit*+ ( swamps & o!r tracts ( ret>d$ dra9age has contribut$ to ?is accel]ation4 ,! nak$1 soil-less upl&s ( "s ( ! once popul\s k+doms ( ! ,ori5t1 notably portions ( ,syria & ,greece1 are sad witnesses ( ! accel]at$ erosion t att5ds cultivation4 ,! erosion ( c]ta9 s\!rn fields ( ! ,unit$ ,/ates 9 ! la/ =ty ye>s is ano!r /rik+ illu/ration4 ,x is d\btful :e!r "s p>ts ( ?is region suff]$ z mu* erosion 9 ! prec$+ five c5turies z !y h dur+ ! la/ "o4 ,on ! o!r h&1 "s comp5sation is f\nd 9 ! res]voirs e/abli%$ = wat]-p[]1 & 9 artificial devices = ret>d+ & /eady+ /ream fl[4 ,9 ! light ( consid]ations su* z ^!1 man may well be reg>d$ n only z a pot5t geological ag5t1 b z dang]\sly s to himself4 ,! hope is t ! intellig5ce t has wr\ght a *ange ( surface conditions s]viceable = ! pres5t1 b dang]\s to ! future1 w be s enl>g$ z to inspire a /ill m intellig5t control ( surface conditions :i* %all compass ! future welf>e z well z transi5t b5efit4 ,human modification ( ! animal & vegetal k+doms4--,man's ag5cy is also com+ to be felt p[]fully 9 ! modification ( ! plant & animal life ( ! l& & ev5 to "s ext5t ( ! sea4 ,! l>g] animals t are n propagat$ by man are fa/ approa*+ ext9ction4 ,at ! pres5t rate ( ext5sion ( man's dom9ion1 a c5tury or s w see ! disappe>ance ( ne>ly e l>ge mammal & reptile t he does n *oose to protect or propagate4 ,by way ( comp5sation1 c]ta9 select$ animals are increas+ & w d\btless cont9ue to increase4 ,! result is1 !re=e1 likely to be a peculi> assemblage ( animal life dep5d5t /rictly on ! *oice ( a dom9ant type1 a /ate ( ?+s t has app>5tly nev] occurr$ 9 an equal degree 9 ! pa/ hi/ory ( ! e>?4 ,h[ f> ! m9or =ms ( life1 especially ! insect life1 & ! d5iz5s ( ! sea1 may be br\ght "u ?is monopoli/ic control may n be pr$ict$ s easily4 ,a simil> pr(\nd transition 9 vegetation is be+ =c$ by man4 ,! native vegetation is rapidly be+ replac$ by select$ v>ieties1 & by v>ieties t take advantage ( conditions furni%$ by man4 ,z ! agricultural control ( ! e>? becomes m complete & effective1 a result t[>d :i* v rapid progress is be+ made1 a new flora ( man's selection w v g5]ally prevail ov] ! :ole l& surface ( ! globe4 ,x is d\btful :e!r at any "t 9 ! hi/ory ( ! e>? *anges ( flora & ( fauna1 & ( surface1 h be5 m rapid ?an ^? t are n[ tak+ place "u ! accel]at+ influ5ce ( man's action1 & ?is accel]at+ influ5ce spr+s n ma9ly f automatic or in/9ctive reaction1 b f consci\s impulse & intellig5t direction4 7#b7 ,! psy*ological factors z su*4--,are ! introduction & ! evolution ( ! psy*ological factors !mselves to be reg>d$ z subjects ( geological /udy8 ,we %all f9d t1 at ! outset1 ! geologic record is a complete blank s f> z cle> evid5ce ( t]re/rial organisms actuat$ by _! own intellig5ce is conc]n$2 t lat]1 organisms ) "s app>5t consci\sness & intellig5ce appe>$1 & t ! m5tal elem5t increas$ apace unto its pres5t atta9m5t4 ,we "k t relation%ips ( a sociological nature arose 9 app>5t feebl5ess1 & gradually evolv$ into m def9ite1 high]1 & m complex =ms4 ,by sociological factors we mean m]ely ^? consci\s relations :i* "o organism be>s to ano!r1 ( :i* ! p>5tal & ! greg>i\s impulses are two fundam5tal expressions4 ,= manife/ reasons1 ! introduction & evolution ( ! psy*ological & sociological factors !mselves h receiv$ little direct recognition z a portion ( geological /udies4 ,! record ( su* factors 9 ! fossils ( pa/ ages is necess>ily obscure & imp]fect1 & ! int]pretation ( :at !re is lacks c]ta9ty & precision4 ,none ! less1 ?is psy*ological record1 ) all its imp]fections1 is beyond valuation1 & mu/1 we ?9k1 come to be an indisp5sable factor 9 ! /udy ( psy*ological & sociological evolution1 = x %[s1 :at no?+ else c %[ equally well1 ! extremely prolong$ hi/ory ( t evolution1 & x gives h9ts ( modes & means :i* no /udy ( exi/+ /ages c equally reveal4 ,! organization ( ! ,cambrian trilobites1 = example1 implies no small developm5t ( ! s5ses & ( ! coord9at+ faculties ev5 at t e>ly /age1 & a /udy ( ! relations ( ^! to _! fell[ creatures op5s up ! fir/ kn[n *apt] 9 ! sociological record ( ! e>?'s inhabitants4 ,f ?is /age onw>d ! progress 9 ! developm5t ( ! high] faculties1 & ( ! sociological relations ( ! lead+ =ms1 is "o ( ! mo/ in/ructive phases ( ! great hi/ory4 ,su* a /udy reveals ! fact t _m que/ions1 n>r[ly suppos$ to be purely human1 h _h _! prototypes 9 ! e>li] exp]i5ces ( ! animal k+dom4 ,"s ( ^! que/ions h f\nd solutions1 tempor>y or p]man5t1 :i* pass$ "u ! te/ ( ages to ^: l5g? human exp]i5ce af=ds no p>allel1 & h receiv$ ! sanction or disapproval ( su* te/s accord+ z !y 7 well or ill adapt$ to ! actual conditions involv$4 ,if "o seeks ! lessons ( hi/ory 9 ! l>ge/ s5se1 he _c wisely neglect ! prolong$ record ( ! great biological family4 ,,ii4 ,,special ,,contributions ,,( ,,! ,,organic ,,k+doms4 ,an ess5tial "p ( ! hi/orical *apt]s ( ! second volume w consi/ ( ! description & illu/ration ( ! life progress ( ! successive p]iods4 ,x w suffice "h to give a prelim9>y synopsis ( ! k9ds ( record made by ! sev]al gr\ps ( plants & animals4 ,a4 ,contributions ( ! ,plant ,k+dom4#bij ,! record ( plants 9 ! e>ly geological ages is extremely imp]fect4 ,9 ! v e>lie/ times ! conditions seem to h be5 :olly unsuit$ to ! pres]vation ( any relics ( life2 b ev5 aft] animal rema9s 7 abundantly pres]v$ 9 ! sea s$im5ts1 ! plant record 0 /ill v meag] = a long p]iod4 ,?is 0 probably due 9 ! ma9 to two *ief causes3 7#a7 ! probable s(tness & p]i%ability ( ! e>ly types ( vegetation1 & 7#b7 ! fact t vegetation is prepond]antly t]re/rial4 ,at no "t has m>9e vegetation rea*$ a high developm5t4 ,l& conditions favor decomposition1 transportation1 & erosion1 & ?r\gh ^!1 de/ruction2 & only "u r occasional & exceptional conditions did ! old l&s leave a good record ( _! life4 ,nev]!less all ! great gr\ps ( plants1 viz4 ! ,?allophytes 7alg1 fungi71 ! ,bryophytes 7mosses1 liv]worts71 ! ,pt]idophytes 7f]ns1 horsetails1 lycopods71 & ! ,sp]matophytes 7gymnosp]ms1 angiosp]ms7 h left "s record4 ,,ref]5ce ,,table ,,( ,,! ,,pr9cipal ,,gr\ps ,,( ,,plants4 ,cyanophyce1 blue-gre5 alg4 ,*lorophyce1 gre5 alg4 ,rhodophyce1 r$ alg4 ,alg & ,phophyce1 br[n alg4 algoid =ms ,diatomace1 diatoms4 ,coccosph]es ,rhabdosph]es ,pelagic alg7874 ,?allophytes ,*>ophyta1 /oneworts4 7,?allus plants7 ,phycomycetes1 alg-fungi1 wat]-molds4 ,ascomycetes1 ascus-fungi1 mildews4 ,fungi & ,basidiomycetes1 basidium-fungi1 mu%rooms4 fungoid cidiomycetes1 cidium-fungi1 8ru/s40 =ms ,s*izomycetes1 8fission-fungi10 bact]ia4 ,myxomycetes1 8animal fungi10 slime-molds4 ,li*5s ,symbiont alg & fungi4 ,bryophytes ,hepatic1 liv]worts4 7,moss plants7 ,musci1 mosses4 ,filicales ,filices1 true f]ns4 ,cycad(ilices1 cycad-f]ns4 ,equisetales ,equiset1 sc\r+-ru%es1 horsetails4 ,pt]idophytes ,calamites4 7,f]n plants7 ,sph5ophyllales4 ,lycopodiace1 club-mosses4 ,lycopodiales ,lepidod5dra4 ,sigill>ia & /igm>ia4 ,cordaite1 cordaites4 ,cycadales ,b5nettite4 ,gymnosp]m 7cycads7 ,cycadace4 7,nak$ se$7 ,conif]1 ev]gre5s4 ,sp]matophytes ,g9kgoace1 g9kgo4 7,se$ plants7 ,angiosp]m ,monocotyl$one1 c]eals1 grasses1 etc4 7,cov]$ ,se$7 7"o-leaf$ se$74 7,fl[]+ ,dicotyl$one1 oaks1 popl>s1 peas1 etc4 plants7 7two-leaf$ se$74 ,! contribution ( ! ,?allophytes 7alg1 fungi1 bact]ia74--,! ,?allophytes embrace ! simple/ types ( plants1 & are probably ! ne>e/ pres5t repres5tatives ( ! ance/ral =ms4 ,"s ( !m are m9ute "o-cell$ organisms1 z simple z an organism c well be conceiv$ to be4 ,! simple blue-gre5 alg ( our fre% wat]s well repres5t ?is class4 ,! mo/ are1 h[ev]1 multicellul>1 & "s 7z ! great seawe$s7 rise to a degree ( complexity & ( a bodily segm5tation resembl+ t ( ! high] plants4 ,! v>i\s species are adapt$ to an extremely wide range ( conditions2 "s live 9 hot spr+s at #agj ,fahr41 & "s 9 ,arctic seas at ! freez+-po9t2 "s fl\ri% 9 fre% wat]1 "s 9 bracki%1 "s 9 salt wat]1 & "s ev5 out ( ! wat]4 ,?is wide adaptation implies an anci5t & pla/ic type4 ,! fact t !y fl\ri% 9 wat]s s hot & sometimes also s sulphur\s z to be fatal to mo/ plants1 sugge/s ! possibility ( _! introduction dur+ ! v e>ly volcanic /ages ( ! e>?1 :ile conditions 7 yet uncong5ial = o!r plants4 ,! geologic "w ( ! !rmal alg is well %[n 9 ! beautiful trav]t9e & s9t] deposits ( ! ,yell[/one ,p>k 7,figs4 #bae & #bah74 ,at ! ,mammo? ,hot ,spr+s ! deposits are calc>e\s1 :ile at mo/ ( ! o!r hot spr+s silici\s deposits are =m$1 9 bo? cases p>tly1 b n :olly1 by ! aid ( alg4 ,! beautiful yell[s1 r$s1 br[ns1 & gre5s ( ^! spr+s are n m9]al color+1 b liv+ plants4#bia ,9 ! calc>e\s wat]s1 ! alg are believ$ to cause ! deposition ( calcium c>bonate f calcium bic>bonate by consum+ ! second equival5t ( c>bon dioxide t r5d]$ ! c>bonate soluble4#bib ,9 ! silici\s wat]s1 ! process ( deposition is n und]/ood4 ,simil> deposits by ! aid ( alg take place 9 ! geys] regions ( ,icel& & ( ,new ,zeal&1 9 ! hot spr+s ( ,c>lsbad1 :]e !y h be5 well /udi$ by ,cohn1#bib & 9 mo/ o!r hot spr+s4 ,! same1 or v simil>1 =ms ( alg ab\nd 9 ne>ly all wat]s1 fre% & salt1 b ! "q :e!r !y make calc>e\s & silici\s deposits 9 notable quantity appe>s n to h receiv$ z yet ! critical inve/igation its importance des]ves1 except 9 a few special cases4 ,x is cle>1 h[ev]1 t 9 ! cool wat]s su* deposits d n rea* ! conspicu\s am\nts t !y atta9 9 ! !rmal spr+s4 ,9 ! %all[ wat]s ( ! ocean1 especially 9 ! w>m] regions1 lime-secret+ alg are abundant & make l>ge contributions to ! lime deposits4 ,among ! high] alg are ! lime-secret+ corall9es or nullipores 7,rhodophyce1 r$ alg71 once reg>d$ z animals1 :i* contribute a notable "p ( ! calc>e\s sub/ance ( coral reefs4 ,!y are important geologic ag5ts 9 ! temp]ate & tropical seas1 & h be5 trac$ z f> back 9 "t z ! e>ly ,paleozoic era4 ,! ,*all5g] reports#bic describe two =ms ( m9ute calc>e\s sph]ical organisms1 ,rhabdosph]es & ,coccosph]es1 z v abundant 9 ! surface-wat]s ( ! temp]ate & tropical seas1 & z important 9 contribut+ to ! calc>e\s deposits ( ! sea-bottoms4 ,! aff9ities ( ^! bodies are 9 d\bt1 b !y are reg>d$ by ,murray z probably pelagic alg4 ,! /oneworts 7,*>ace71 an ab]rant gr\p ( alg inhabit+ fre% & bracki% wat]1 secrete notable quantities ( calcium c>bonate 9 & ar\nd _! tissues1 & ! accumulation ( ^! gives rise to m>l or lime/one4 ,x has rec5tly be5 urg$ t our s-call$ %ell-m>ls are ma9ly due to ,*>1#bid ! molluscan %ells be+ incid5tal r ?an ess5tial con/itu5ts4 ,9 v anci5t & also 9 "s ( ! lat] /rata1 !re are lime/ones t d n c>ry any visible fossils1 & _! orig9 is1 !re=e1 debatable4 ,!re are also n a few lime/ones t are made up ( a f9e-gra9$ base ?r\gh :i* are scatt]$ molluscan %ells1 corals1 etc41 9 a f9e /ate ( pres]vation4 ,! condition ( ^! fossils be>s r adv]sely on ! view t %ells1 etc41 h be5 p[d]$ 9 suffici5t numb]s & to a suffici5t degree to =m ! compact base4 ,9 all ^! cases ! usual explanations leave some?+ to be desir$4 ,x is wor? consid]+ :e!r l[ =ms ( plants may n be among ! undemon/rat$ ag5ts 9 =m+ ^! app>5tly unfossilif]\s lime/ones or p>ts ( lime/ones4 ,! calcium c>bonate deposit$ by ! alg is 9 m9ute & delicate =m1 & is usually cry/all9e :ile yet 9 ! liv+ tissues4 ,x is1 !re=e1 easily subject to comm9ution & to su* fur!r cry/allization z w\ld obscure ! m9ute features t con/itute ! evid5ces ( algal orig94 ,! m complex & conspicu\s alg1 ! seawe$s1 h left impressions ( _! /ems & fronds on ! m>9e b$s ( mo/ ( ! p]iods1 b !y are usually obscure4 ,seawe$s are p]haps ! s\rce ( ! vegetal matt] 9 c]ta9 c>bonace\s %ales & lime/ones4 ,z seawe$s extract brom9e & iod9e & c]ta9 metallic +r$i5ts f ! sea-wat]1 "s ( ! iod9e & brom9e spr+s issu+ f anci5t m>9e deposits1 & c]ta9 ores1 may owe _! orig9 to anci5t seawe$s4 ,diatoms1 m9ute plants ( ! ,?allophyte gr\p1 secrete a delicate framework ( silica :i* becomes a contribution to ! silici\s deposits4 ,diatoms h sometimes contribut$ ! mat]ial = v consid]able b$s1 su* z ^? ( ! ooze-bogs n[ =m+ 9 ! m>%es ( ! geys] bas9s ( ! ,yell[/one ,p>k1#bie & ! diatom oozes ( ! deep sea 7,fig4 #cec1 p4 #dbe74 ,fungi1 = obvi\s reasons1 h left b scant traces ( !mselves4 ,bact]ia are believ$ to be recognizable z f> back z ! ,paleozoic era4 ,!y are n[ ! *ief ag5ts 9 ! decomposition ( organic matt]1 & may be reg>d$ z ! prime enemies ( ! fossil record4 ,x is probable t simil> decomposition took place actively 9 ! e>lie/ ages1 = o!rwise ! rema9s ( ! anci5t organisms %\ld be m abundant4 ,!re is h5ce a !oretical probability t bact]ia fl\ri%$ z f> back z ! /ratigraphic record goes4 ,n unlikely !y 7 orig9ally simple alg t turn$ f ! primitive habit ( mak+ _! own food1 to liv+ on o!r organisms or _! rema9s1 & 9 s do+ lo/ _! p[] ( manufactur+ *lorophyll & ( us+ inorganic c>bon comp\nds4 ,_! rem>kable adaptation to ! mo/ v>i$ conditions1 & _! extraord9>y ability to endure ! greate/ vicissitudes ( environm5t1 support ! view t !y are a v anci5t & pla/ic =m4 ,at pres5t c]ta9 bact]ia are important to high] vegetation because ( _! ability to use ! free nitrog5 ( ! atmosph]e & to comb9e x into =ms available = ! high] plants4 ,x is n improbable t !y h subs]v$ ?is important function ?r\gh all ! kn[n ages4 ,"s exp]im5ts seem to %[ t c]ta9 ( ! exi/+ alg h ?is p[]1 & possibly ! ance/ral =ms ( plants possess$ x4 ,! bact]ia1 be+ a d]iv$ & n an orig9al =m1 c\ld n h p]=m$ ! function = ! fir/ plants4 ,x is possible1 ( c\rse1 t ! inorganic supply ( nitrog5 comp\nds 0 suffici5t = plant life at ! outset4 ,! contribution ( ! ,bryophytes 7liv]worts1 mosses74--,! mosses & liv]worts h left no c]ta9 record ( _! "w 9 ! e>li] & middle geologic eras1 &1 if !y exi/$ at all1 _! contributions 7 unimportant4 ,al?\gh l[ =ms ( plant life1 !y are n primitive ones1 z !y are *>act]iz$ by a def9ite alt]nation ( g5]ations imply+ a consid]able "t antec$5t to ! atta9m5t ( _! pres5t =ms2 h5ce !re are no v cog5t !oretical reasons = assign+ !m a place 9 e>ly geologic hi/ory1 ?\gh _! abs5ce _c be affirm$4 ,"s botani/s ?9k ! ,pt]idophytes 7 d]iv$ f "s ance/ral =m ( liv]wort1 :i*1 if true1 w\ld require ! pres5ce ( ! latt] 9 an e>ly geologic p]iod2 b ! negative geological evid5ce relative to _! pres5ce favors ! alt]native view t ! ,pt]idophytes 7 d]iv$ f "s =m ( ! ,?allophytes by an indep5d5t l9e4 ,9 rec5t times1 c]ta9 ( ! mosses1 especially ! sphagnum mosses1 h play$ a notable "p 9 ! =mation ( peat accumulations4 ,= ?is1 _! habit ( gr[+ 9 bogs1 & ( dy+ bel[ :ile !y cont9ue to gr[ above admirably fits !m4 ,! contribution ( ! ,pt]idophytes 7f]ns1 horsetails1 lycopods1 ,sph5ophyllum74--,! ,pt]idophytes include ! mo/ important fossil plants ( ! e>li] & middle geologic eras4 ,to !m we owe *iefly ! great c>bonace\s deposits ( ! ,coal ,measures & probably mo/ ( ! dissem9at$ c>bons ( ! e>ly & middle eras2 p]haps also mu* ( ! natural oil & gas4 ,_! special "w is s conspicu\s t x w be not$ at l5g? 9 ! *apt]s on ! ,devonian & ,c>bonif]\s p]iods1 & h5ce may be pass$ "h ) brevity4 ,! f]ns1 n[ kn[n m = _! beauty ?an _! importance1 are ! repres5tative type ( ! gr\p1 & are really a wond]ful family1 hav+ pres]v$ _! *>act]i/ic leaf-=ms ) a p]si/5ce atta9$ by no o!r gr\p ( plants4 ,! ,paleozoic f]ns are recognizable z su* by e "o1 irrespective ( botanical k2 inde$ x is ! detection ( ! diff]5ces1 r ?an ! resemblances1 betwe5 ! anci5t & mod]n =ms1 t requires exp]t k4 ,?is cont9uity %[s t s9ce _! introduction ! *anges ( climate h nev] be5 s great z to prev5t _! propagation1 )\t radical modification1 9 "s "p ( ! globe1 & ?is fact r n>r[ly limits ! range ( surface temp]atures1 & ( o!r climatic vicissitudes4 ,! p]si/5ce ( ! ,equiset 7horsetails1 sc\r+-ru%es7 & ! lycopods 7club-mosses7 be>s l te/imony1 z does ! p]si/5ce ( life 9 g5]al2 b ! r delicate f]ns are p]haps m obvi\sly significant ?an mo/ organisms4 ,! contribution ( ! ,sp]matophytes 7se$ plants1 includ+ gymnosp]ms or 8ev]gre5s0 & angiosp]ms or 8fl[]+ plants074--,! angiosp]ms1 ! dom9ant gr\p to-day1 make _! appe>ance 9 ! record 9 ! latt] "p ( ! ,mesozoic era1 & _! contribution is1 !re=e1 relatively mod]n4 ,!y contribut$ to ! coals1 lignites1 oils1 & organic gases ( ! late geological p]iods1 z did ! ,pt]idophytes 9 ! e>li] p]iods1 ! latt] p>ticipat+1 h[ev]1 9 ! late deposits4 ,p]haps ! mo/ important function ( ! ,sp]matophytes lay 9 _! sup]ior s]viceability z food = ! high] l& animals1 by virtue ( _! se$s1 fruits1 & foliage4 ,nei!r ! ,?allophytes1 ,bryophytes1 nor ,pt]idophytes1 nor all comb9$1 approa* ! ,sp]matophytes 9 food value = ! high] types ( animal life1 & x is d\btful :e!r ! high] evolution ( ! l& animals c\ld h tak5 place )\t ! previ\s introduction ( ! se$ plants4 ,x w be not$ 9 ! hi/orical n>rative t ! great plac5tal gr\p ( mammals came 9 & deploy$ ) m>vel\s rapidity1 z geological progress goes1 soon aft] ! ,sp]matophytes became ! dom9ant =m ( vegetation4 ,plant life t]re/rial r ?an m>9e4--,x is to be notic$ t ! *ief developm5t ( all ! great gr\ps ( plants took place on ! l&1 or 9 ! l&-wat]s1 r ?an 9 ! sea4 ,?is is preem95tly true ( ! high] types1 & appe>s also to be true ( ev5 ! ,?allophytes1 al?\gh ! numb] ( individual alg & _! total mass is v mu* great] 9 ! sea ?an on ! l& & 9 ! l&-wat]s4 ,b ! fre%-wat] alg appe> to possess 9 a high] degree ?an ! m>9e =ms ^? pla/ic & g]m9al *>act]s f :i* new =ms spr+1 & are probably to be reg>d$ z ! p>5tal type4 ,^! are facts to be pond]$ on1 s9ce x has be5 ! curr5t op9ion ( geologi/s t life arose 9 ! sea & 0 propagat$ !nce to ! l&4 ,! alt]native view t life develop$ prim>ily on ! l& & 9 ! l&-wat]s & migrat$ to ! sea is n1 h[ev]1 )\t its support 9 ! plant _w1 z we ?us see1 & ! plant _w 0 ! primitive "o2 ! dep5d5t animal _w necess>ily foll[$ its developm5t4 ,! hypo!sis ( a t]re/rial orig9 ( life ?r[s a v sugge/ive cross-light on _m geological problems1 z w be se5 lat]1 & x may well be ent]ta9$ z an alt]native work+ hypo!sis until ! facts are m fully develop$4 ,b4 ,contributions ( ! ,animal ,k+dom4#bif ,z already not$1 animal life is dep5d5t on ! decomposition ( matt] organiz$ by gre5 plants1 & ! conv]sion ( its pot5tial en]gy into active =ms4 ,animals are1 !re=e1 dynamic r ?an con/ructive ag5cies4 ,nev]!less !y trans=m organic vegetal matt] into organic animal matt]1 & ?is is sometimes really an advance 9 organization4 ,! organiz$ animal matt] is subject to pres]vation 9 "s small degree1 ?\gh x usually p]i%es4 ,"s contribution is1 !re=e1 made to ! organic deposits1 *iefly 9 ! =m ( hydroc>bons4 ,x is ! view ( "s geologi/s t ! natural oils & gases h an animal orig9 9 ! ma94 ,,ref]5ce ,,table ,,( ,,! ,,pr9cipal ,,gr\ps ,,( ,,animals4#big ,protozoa ,rhizopoda ,=am9if]a4 7,! simple/ ,radiol>ia4 animals7 ,flagellata ,infusoria ,unkn[n 9 fossil /ate4 ,greg>9a ,cl5t]ata ,porif]a ,spongi ,calc>e\s sponges4 7,sponges1 ,silici\s sponges4 corals1 ,cnid>ia ,an?ozoa1 coral polyps4 jellyfi%es7 ,hydrozoa1 hydroids & m$us4 ,e*9od]mata ,pelmatozoa ,cy/oidea1 cy/ids4 7,cr9oids1 ,cr9oidea1 /one lilies4 />fi%es1 ,bla/oidea1 bla/ids4 sea-ur*9s7 ,a/]ozoa ,ophiuroidea1 brittle-/>s ,a/]oidea1 />fi%es4 ,e*9ozoa ,e*9oidea1 sea-ur*9s4 ,holo?uroidea1 sea-cucumb]s4 ,v]mes ,platyhelm9!s 7,worms7 ,rotif]a ,nema!lm9!s ,r>e z fossils4 ,gephyrea ,annelida1 sea-worms4 ,molluscoidea ,bryozoa1 sea-mosses4 7,mollusc-l =ms7 ,bra*iopoda1 lamp-%ells4 ,mollusca ,pelecypoda1 lamellibran*s1 bivalves4 7,molluscs7 ,scaphopoda1 tusk-%ells4 ,amph9eura1 *iton4 ,ga/ropoda1 univalves1 snails1 etc4 ,cephalopoda1 nautilus1 cuttlefi%4 ,ar?ropoda ,bran*iata ,cru/acea4 7,! ,trilobita1 trilobites4 articulates7 ,giganto/raca1 horse-%oe crabs4 ,entomo/raca1 o/racoids1 b>nacles4 ,malaco/raca1 lob/]s1 crabs4 ,tra*eata ,myriapoda1 c5tip$es4 ,ara*noidea1 spid]s1 scorpions4 ,insecta1 insects4 ,cyclo/omata1 lampreys4 ,pisces ,sela*ii1 %>ks4 7fi%es7 ,holocephali1 spook-fi%es4 ,dipnoi1 lung-fi%es4 ,teleo/omi1 ganoids & teleosus4 7common fi%es74 ,v]tebrata ,amphibia1 amphibians1 batra*ians4 ,reptilia1 reptiles4 ,aves1 birds4 ,mammalia ,proto!ria1 monotremes4 7mammals7 ,meta!ria1 m>supials4 ,eu!ria1 plac5tals4 ,z dynamic organisms animals h ne$ = support+- & work+-frames1 = protective cov]+ or h\s+1 & = (f5sive & def5sive weapons1 & ^! h be5 con/ruct$ *iefly out ( inorganic matt]1 & subord9ately ( indurat$ organic matt]4 ,x is ?r\gh ^! t animals h made _! *ief contribution to ! mat]ial ( ! geologic record4 ,skeletons & o!r h>d p>ts to give int]nal /iffness or firmness2 %ells1 plates1 indurat$ integum5ts1 & v>i\s o!r =ms ( ext]nal protection2 tee?1 sp9es1 horns1 & o!r means ( ga!r+ & ma/icat+ food1 & ( attack & def5se1 contribute mat]ial to ! deposits1 & =m a record ( ! life activities & ( ! physiographic environm5t4 ,all ( ! eight gr\ps ( animals1 viz4 ,protozoa1 ,cl5t]ata1 ,e*9od]mata1 ,v]mes1 ,molluscoidea1 ,mollusca1 ,ar?ropoda1 & ,v]tebrata1 h left "s record1 b x is 9 all cases a v imp]fect "o4 ,! contribution ( ! ,protozoa4--,! ,protozoa are relat$ to ! animal k+dom mu* z ! ,?allophytes are to ! vegetable1 & ! two be> a close /ructural resemblance to "o ano!r4 ,s ne>1 inde$1 d ! ,protozoa & ! ,?allophytes approa* "o ano!r 9 _! m9ut5ess & simplicity1 t ! place ( n a few organisms is 9 d\bt1 & ! two k+doms1 9 g5]al s diff]5t1 seem "h to bl5d 9 ! gr\p ,flagellata4 ,! ,protozoa are usually v m9ute "o-cell$ organisms ) v little diff]5tiation ( tissue or organs4 ,( ! f\r classes ( ,protozoa1 only "o1 ! ,rhizopoda1 is f\nd 9 ! fossil /ate4 ,! rhizopods secrete silici\s skeletons1 & calc>e\s1 silici\s1 & *it9\s te/s ( a great v>iety ( =ms1 & ?is gives !m geologic importance4 ,! deep-sea oozes & ! *alk deposits are _! be/-kn[n contributions at pres5t4 ,!y h probably play$ a m important rle 9 ! =mation ( ord9>y lime/ones & silici\s silts ?an c be demon/rat$1 because ( ! delicacy ( _! relics & ! ease ) :i* ^! are pulv]iz$ by wave-action 9 ! %all[ seas1 or *ang$ by recry/allization or by concretion>y aggregation4 ,! globig]9a oozes are =m$ l>gely f ! calc>e\s %ells ( ,=am9if]a 7,fig4 #cea71 "o ( ! ord]s ( rhizopods1 among :i* ! g5us ,globig]9a is a lead+ =m4 ,^? =ms :i* make ! deep-sea oozes live1 n on ! bottom1 b ne> ! surface ( ! op5 sea1 & on ! dea? ( ! organisms1 ! %ells1 te/s1 & skeletons s9k to ! bottom4 ,*alk is =m$ 9 a simil> way f calc>e\s ,=am9if]a1 b n necess>ily 9 v deep wat]4 ,=am9if]a live 9 %all[ wat] z well z 9 ! op5 sea1 & 9 ?is case !y sometimes creep on ! bottom or are atta*$ to alg1 b _! deposits 9 %all[ wat] are usually mu* obscur$ by o!r k9ds ( deposition & by de/ructive action4 ,"s ( ! =am9if]al %ells are divid$ into *amb]s & assume v>i\s spiral =ms1 ( :i* ! ,nummulites1 nam$ f _! resemblance to co9s1 are notable examples4 ,^! =m$ an important "p ( ! nummulitic lime/one ( ! ,eoc5e p]iod4 ,! radiol>ian ooze is *>act]iz$ by ! silici\s te/s ( v>i\s memb]s ( ! silica-be>+ ord]1 ,radiol>ia4 ,! 8,b>badoes e>?0 & 8,tripoli0 are notable deposits ( fossil radiol>ians4 ,! contribution ( ! ,cl5t]ata4--,! ,cl5t]ata embrace ! sponges1 ! coral polyps 7,an?ozoa71 & ! hydroids & m$us 7,hydrozoa74 ,! contribution ( coral polyps to ! =mation ( lime/one is mo/ important1 & is too famili> to require elaboration "h4 ,! corals range ?r\gh\t ne>ly ! :ole fossilif]\s s]ies1 & _! developm5t w be foll[$ & illu/rat$ 9 ! hi/orical *apt]s4 ,! sponges are widely repres5t$ by _! spicules1 & n uncommonly _! aggregate =m is pres]v$ ev5 9 v anci5t /rata4 ,_! contribution is l>gely silici\s1 b is p>tly calc>e\s4 ,! hydroids & m$us h left little trace ( !mselves 9 ! rocks1 al?\gh impressions suppos$ to repres5t m$us are f\nd 9 /rata z e>ly z ! ,cambrian4 ,c]ta9 coral-l =ms1 z ! ,millepores1 ,tubul>ia1 & ,/romatopora1 are class$ z ,hydrozoa4 ,! graptolites1 delicate leaf-l float+ =ms1 v s]viceable 9 m>k+ exact horizons on diff]5t cont95ts because ( _! free di/ribution1 are also class$ "h4 ,! contribution ( ! ,e*9od]mata4--,"u ! e*9od]ms are gr\p$ ! cr9oids 7sea-lilies71 cy/oids1 bla/oids1 ophiuroids 7brittle />s71 a/]oids 7/>fi%es71 e*9oids 7sea-ur*9s71 & holo?uroids 7sea-cucumb]s74 ,?is is "o ( ! m>k$ gr\ps ( anci5t z well z mod]n life1 & its beautiful fossils grace e p]iod 9 :i* life relics are well pres]v$4 ,! cy/oids & cr9oids1 & lat] ! bla/oids1 7 prom95t 9 ! ,paleozoic ages1 :ile ! rema9+ =ms 7 m conspicu\s lat]1 ?\gh e>ly introduc$4 ,all divisions1 except ! holo?uroids1 ^: s(tness prev5t$1 h left a good record1 z fossil records g4 ,_! relics are *iefly calc>e\s1 & !y mo/ ab\nd 9 ! lime/ones1 "s ( :i* are l>gely made up ( _! rema9s1 z ! encr9ital lime/one 7,fig4 #cdi74 ,!y w be subjects ( frequ5t comm5t & illu/ration 9 ! hi/orical *apt]s4 ,! contribution ( ! ,v]mes4--,mo/ ( ! worms are ill adapt$ to fossilization & are n kn[n 9 ! fossil =m4 ,! segm5tal worms ( ! sea1 ! annelids1 h[ev]1 left "s traces ( !mselves 9 tubes & bor+s & 9 tracks & sometimes by fossil jaws & tee?4 ,!y range f ! e>lie/ fossil-m>k$ horizons onw>d1 b seem to h always be5 an inf]ior gr\p4 ,! contribution ( ! ,molluscoidea4--,?is gr\p includes ! bryozoans1 ^: fossil products closely resemble ! m9ute-cell$ corals1 & ! bra*iopods1 ^: %ells closely resemble ^? ( ! molluscs4 ,bo? are calc>e\s & make important contributions to ! =mation ( lime/one 7,fig4 #cej74 ,a few bra*iopods secrete calcium phosphate in/ead ( calcium c>bonate4 ,bo? classes h a great geologic range & _! fossils are valuable aids 9 id5tify+ & correlat+ =mations4 ,probably ! bra*iopods are m utiliz$ = ?is purpose ?an any o!r s+le class4 ,!y are ! symbol ( cons]vatism & p]si/5ce1 rang+ f ! ,cambrian to ! pres5t "t1 & embrac+ "s =ms t h sc>cely *ang$ to ! ext5t ( g5]ic diff]5ce 9 t "t4 ,! contribution ( ! ,mollusca4--,! molluscs h also rang$ f ! e>lie/ well-record$ times1 & "s divisions1 z ! pelecypods 7lamellibran*s1 embrac+ clams1 oy/]s1 etc47 & ga/ropods 7snails1 etc471 h und]gone no v m>k$ *ange beyond a r ample & progressive developm5t2 b o!rs1 z ! cephalopods 7nautilus1 squids1 cuttlefi%1 etc471 m>k out ! progress ( ! ages by di/9ct & /rik+ *anges ( =m4 ,_! %ells are *iefly calc>e\s & !y h contribut$ mat]ially to ! =mation ( lime/one4 ,muddy & s&y bottoms are1 h[ev]1 m cong5ial to ! pelecypods & ga/ropods ?an to ! corals1 cr9oids1 & _m o!r lime/one-=m+ types1 & h5ce fossils ( ^! molluscs frequ5tly ab\nd 9 %ales & s&/ones & give !m a calc>e\s elem5t4 ,9 s&/ones1 h[ev]1 ! calc>e\s matt] is (t5 dissolv$ out & only ! ca/s ( ! %ells rema94 ,! molluscs w be mu* cit$ & illu/rat$ 9 ! hi/orical *apt]s4 ,! contribution ( ! ,ar?ropoda4--,?is gr\p embraces ! cru/aceans1 myriopods1 spid]s1 & insects4 ,! h>d p>ts ( _! bodies are ma9ly horny or *it9\s =ms ( organic matt]1 & h5ce _! relics diff] notably f ! inorganic calc>e\s & silici\s rema9s ( mo/ ( ! prec$+ =ms4 ,! ,ar?ropoda did n at any "t =m a notable /ratum ( rock4 ,_! geologic value lies *iefly 9 :at !y tea* ( ! progress ( life & its relations1 & ! aid !y r5d] 9 correlation & id5tification4 ,9 ^! respects ! gr\p is a notable "o4 ,x 0 repres5t$ 9 ! e>ly fossilif]\s /rata by ! trilobites1 "o ( ! mo/ int]e/+ ( all types ( fossils4 ,^! 7 probably ! mo/ highly develop$ organisms ( _! times & give ! cle>e/ h9ts ( ! /age ( psy*ological & sociological developm5t t _h be5 rea*$ :5 fir/ ! record ( life is op5$ to u4 ,! record ( ! myriopods1 spid]s1 & insects dates f ! middle ,paleozoic1 & gives ! fir/ cle> h9ts ( animal life on ! l&4 ,! contribution ( ! ,v]tebrata4--,9 ! v]tebrates ! dynamic or work+ organism may be said to rea* its highe/ expression1 unless x be 9 ! fly+ insects1 & _! inorganic residue becomes relatively unimportant 9 rock =mation4 ,al?\gh ! greate/ ( all animal types 9 mo/ respects1 x has nev] =m$ m ?an trivial b$s ( rocks4 ,!re are occasional 8bone b$s10 b !y are ?9 & limit$ 9 ext5t1 & only p>tially =m$ ( v]tebrate matt]4 ,! geological importance ( ! v]tebrates lies 9 ! high] field ( life evolution & 9 its m5tal accompanim5t4 ,fi%es except$1 ! v]tebrates are ma9ly l& types1 & h = _! *ief colleagues plants & insects4 ,! o!r gr\ps ( animals are ma9ly1 ?\gh n :olly1 m>9e4 ,! v]tebrates h little place 9 ! ,paleozoic record1 except ne> its close1 b !y dom9ate ! ,mesozoic & ,c5ozoic eras1 & are conspicu\sly ! ma/] type to day4 ,,iii4 ,,! ,,associations ,,& ,,ecological ,,relations ,,( ,,life4 ,a4 ,! ,basis ( ,floras & ,faunas4 ,geologic int]e/ is n conf9$ to ! k9ds ( plants & animals t h liv$ & ! contributions !y h made to ! deposits1 b embraces also _! assemblage into floras & faunas1 & ! relations ( ^! assemblages to ! prevail+ physiographic features4 ,^! assemblages & relation%ips are among ! mo/ sugge/ive factors ( ! e>?'s evolution1 & are ! mo/ in/ructive = purposes ( comp>ison ) human hi/ory1 & = =eca/+ ! future ( man & ( ! :ole biological k+dom4 ,moreov]1 floras & faunas1 z su*1 are us$ 9 ! correlation ( =mations1 & 9 ?is application !y give sur] results ?an correlations by individual species4 ,a p>ticul> species may live f> beyond ! usual p]iod ( a species1 & if fossiliz$ 9 "o region 9 its e>ly hi/ory & 9 ano!r 9 its late hi/ory1 ! two =mations might be ref]r$ errone\sly to ! same /age4 ,?is is f> less likely to happ5 ) a :ole assemblage ( =ms4 ,!re is a simil> liability to error 9 int]pret+ migrations on ! basis ( a s+le or a few species1 = a s+le species or a few species may be transport$ by unusual or accid5tal means1 s to speak1 :5 !re is no normal pa?way = g5]al migration1 & :5 no sy/ematic migration takes place4 ,9 mo/ ( ! great que/ions t arise conc]n+ ! connections & dissev]ances ( ! cont95ts1 & conc]n+ ! unions & sep>ations ( ! oceans1 :i* are ! fundam5tal causes ( ! migrations & ( ! isolations ( plants & animals1 typical floras & faunas are to be /udi$1 r ?an isolat$ species or sporadic =ms4 ,a brief sket* ( ! lead+ causes & consequ5ces ( ^! special assemblages ( plants & animals may aid 9 appreciat+ ! und]ly+ significance ( floras & faunas1 & 9 int]pret+ _! mean+ z !y are met 9 ! /udy ( ! /rata4 ,a "p ( ^! gr[ out ( ! relations ( ! organisms to "o ano!r1 & a "p out ( ! relations ( ! organisms to _! environm5t4 7#a7 ,assemblages ,influ5c$ by ! ,mutual ,relations ( ,organisms4 7a7 ,food relations4--,! relations ( food-supply are among ! mo/ obvi\s reasons = assemblages4 ,z animals are dep5d5t directly or indirectly on plants = _! food1 !y mu/ ga!r :]e ! plants gr[1 or 9 ! curr5ts 9 :i* ! plant products are borne4 ,:atev] det]m9es an assemblage ( plants also causes1 or at lea/ invites1 an assemblage ( animals4 ,:atev] causes an assemblage ( p>ticul> plants1 invites an assemblage ( ! p>ticul> animals t use ^! plants4 ,animals t fe$ on plants are 9 turn prey$ ^u by o!r animals1 & ^! 9 turn by o!rs4 ,a :ole tra9 ( organisms may1 !re=e1 be ga!r$ into a region by ! conditions t fo/] a c]ta9 k9d ( vegetation !re4 ,9 int]pret+ ! physical significance ( su* a tra91 x is obvi\s t ! head ( ! tra9 c>ries ! fundam5tal mean+4 ,! dep5d5t creatures t foll[ ! prim>y =ms may be only incid5tally1 & p]haps v slightly1 adapt$ to ! physical environm5t4 7b7 ,adaptive relations4--,organisms dep5d+ on o!r organisms = food or o!r necess>y conditions ( life1 pres5t _m =ms ( adaptation ! bett] to secure _! food & to use x4 ,^! adaptations are ! consequ5ces & ! signs ( ! assemblage1 & are ( ! greate/ s]vice 9 int]pret+ ! place & significance ( ! organisms 9 ! assemblage4 ,tee? usually reveal ! food ( _! possessors1 & h5ce tee? are among ! mo/ significant ( fossils4 ,=tunately _! functions require !m to be h>d & durable1 & h5ce well suit$ to fossilization4 ,! gr[? ( l[ plants into trees =c$ a notable s]ies ( adaptations 9 ! animals t f$ ^u !m 9 ! matt] ( height1 ( rea*+ memb]s1 ( climb+1 & probably at l5g? ( p>a*ut+ & fly+4 ,9 ^! & simil> ways ! floras & faunas took on special phases because ( ! mutual relations ( _! memb]s4 7c7 ,competitive relations4--,! assembl+ ( plants & animals1 ) _! prodigi\s possibilities ( multiplication1 br\ght competition1 & ) x a /ruggle = food :i* (t5 became a /ruggle = exi/5ce1 & out ( ?is grew innum]able modifications ( =m & habit4 ,^! h become s famili> s9ce ! great awak5+ caus$ by ! doctr9es ( ,d>w9 & ,wallace t !y ne$ no elaboration "h4 7d7 ,(f5sive & def5sive relations4--,)9 limits1 plants are b5efit$ by ! fe$+ ( animals & respond by develop+ se$s & fruits t especially invite su* action1 _! comp5sation be+ f\nd 9 plant+ & di/ribution4 ,x is obvi\s t1 on ! :ole1 ! cont9u$ gr[? ( plants is l>gely dep5d5t on ! r5ewal ( a supply ( c>bon dioxide ?r\gh ! ag5cy ( animals & "s plants1 bact]ia 9 p>ticul>4 ,o!rwise ! supply w\ld become s r$uc$ z to greatly limit plant life4 ,x has be5 e/imat$#bih t ! :ole ( ! pres5t supply ( c>bon dioxide w\ld be consum$ by plants 9 "o hundr$ ye>s if ! consumption cont9u$ at ! pres5t rate & no c>bon dioxide 0 return$4 ,x is n[ well kn[n t ! s-call$ decay by :i* c>bon dioxide is fre$ is due m to microscopic organisms ?an to inorganic processes4 ,x seems cle>1 !re=e1 t ! cont9u$ activity ( plants is l>gely due to _! consumption by animals & o!r plants4 ,b /ill1 ?\gh ! l>g] good ( plants is cons]v$ by ! pr$ace\s action ( animals1 & ( c]ta9 p>asitic & saprophytic plants1 _! individual pres]vation is (t5 cons]v$ by def5sive devices1 su* z ?orns1 poisons1 bitt] comp\nds1 etc4 ,?is is notably true 9 des]t regions :]e ! conditions are h>d & ! total ext9ction ( plants w\ld be ?reat5$ if animals 7 p]mitt$ to fe$ freely ^u !m4 ,)9 ! animal _w1 ! prey+ ( "o =m ^u ano!r is ! ma9 s\rce ( t great /ruggle = exi/5ce :i* has *>act]iz$ ! :ole kn[n hi/ory ( life1 & has be5 "o ( ! influ5tial factors 9 %ap+ ! evolution ( life & 9 modify+ ! special aspects assum$ by ! floras & faunas ( ea* p]iod4 ,impli$ =ms ( life4--,! full mean+ ( ! fossils ( any p]iod c only be ga!r$ by duly consid]+ ^! relation%ips 9 _! int]pretation4 ,! exi/5ce ( animals implies ! exi/5ce ( plants 9 support+ abundance1 :e!r ! record conta9s _! relics or n2 an animal ) a protective cov]+ implies an enemy2 a too? ( a specific k9d implies ! appropriate class ( food1 etc4 ,:ile inf]5ces ( ?is k9d are subject to error1 !y are at pres5t ! only means by :i* ! faunas & floras ( mo/ ages c be r\nd$ out into a rational assemblage ( organisms1 t is1 an assemblage t af=ds ! necess>y food = its memb]s & an adequate function = ! (f5sive & def5sive devices :i* its memb]s pres5t4 ,only a small "p ( ! life t liv$ 0 fossiliz$1 & only a small "p ( ! fossils actually c>ri$ 9 ! /rata h be5 collect$1 because only a small "p ( ! /rata are expos$ at ! surface4 ,! direct record n[ accessible is1 !re=e1 v incomplete & h5ce ! ne$--& 9 ! ne$ ! excuse--= add+ ! =ms t are impli$ by ! "* ( ! kn[n fossils4 7#b7 ,assemblages ,influ5c$ by ,environm5t4 ,x has be5 not$ t "s animals dep5d = exi/5ce on o!r animals2 t ultimately all animals dep5d on plants1 & t gre5 plants alone c make food directly f inorganic mat]ial4 ,gre5 plants1 !re=e1 head ! tra9 ( dep5d5cies1 & _! relations to ! physical conditions t surr\nd !m are ! primal relations4 ,plant societies4#bii--,! control ( physical conditions has be5 suffici5t to develop special associations or societies ( plants by fo/]+ ^? adapt$ to ^! conditions & elim9at+ ^? t are n4 ,among ^! are 7#a7 ! hydrophytes 78wat] plants071 embrac+ ^? t gr[ 9 wat] or 9 v wet situations2 7#b7 x]ophytes 78dr\ght plants071 embrac+ ! opposite class1 :i* are adapt$ to v dry situations2 7#c7 mesophytes1 includ+ ^? suit$ to conditions ly+ betwe5 ^! extremes1 ! great middle class to :i* ! prevail+ upl& vegetation belongs2 & 7#d7 ! halophytes 78salt plants071 :i* are dep5d5t on ! pres5ce ( c]ta9 salts1 & embrace su* plants z are f\nd on ! seacoa/1 ar\nd salt spr+s1 on alkal9e flats1 etc4 ,! *>act]s :i* di/+ui% ! x]ophytes f ! hydrophytes & mesophytes h special geological int]e/1 z !y aid 9 det]m9+ ! climatic conditions1 a feature ^: int]e/ increases z ! v>iability ( ! anci5t climates is m fully recogniz$4 ,)9 ^! great] gr\ps !re are special m9or associations det]m9$ by soil1 temp]ature1 topography1 subjac5t /rata1 & by ! relations ( ! plants to "o ano!r4#cjj ,^! natural gr\ps are valuable indications ( ! agricultural capabilities ( ! di/ricts occupi$ by !m4 ,!y may be reg>d$ z ! outcome ( ,nature's exp]im5ts 9 crop-rais+1 runn+ consecutively ?r\gh ?\s&s ( ye>s4 ,!y are natural correlations ( compatible memb]s into communities ( plants4 ,"s memb]s ( ! society are obvi\sly dep5d5t on o!rs1 z c]ta9 =ms ( und]gr[? on ! %ad[+ ( ! upp] gr[?1 z ( v9es ^u support+-trees1 etc4 ,!re is probably a m occult relation 9 "s cases1 ! effects ( c]ta9 plants on ! soil be+ sometimes advantage\s to o!r plants1 & sometimes h>mful1 z illu/rat$ 9 ! conditions t require a rotation ( crops4 ,! *ief po9t ( geologic int]e/ lies 9 ! fact t floras are n m]e miscellane\s mixtures ( plants t happ5 to live 9 a giv5 area at a giv5 p]iod1 b are organiz$ communities1 9 a m or less def9ite s5se4 ,!y !re=e imply m or less def9itely ! physical conditions :i* are cong5ial to !m1 & ?us furni% ! basis = int]pret+ su* conditions 9 ! pa/1 s f> z ! floras are well pres]v$4 ,! faunas1 especially ! l& faunas1 be+ prim>ily dep5d5t on ! floras1 furni% a basis = int]pretations ( l import4 ,b4 ,! ,influ5ce ( ,geographic ,conditions on ! ,evolution ( ,floras & ,faunas4 ,! geographic features ( ! e>? impose on organisms a complex s]ies ( influ5ces :i* modify ! evolution ( life & produce faunal & floral v>iation on a l>ge scale4 ,! l>g] assemblages ( life1 :i* inhabit a cont95t or dwell 9 a great sea1 are designat$ faunas & floras1 z well z ! small] assemblages j discuss$1 b obvi\sly 9 a broad] & 9 a diff]5t s5se4 ,! dissev]ance ( ! l& by ! sea1 or ( ! sea by ! l&1 isolates ! life & =ces indep5d5t developm5t4 ,! introduction ( cold zones1 des]t tracts1 or o!r pot5t climatic belts has some:at ! same effect4 ,s1 measurably1 does ! rais+ ( a m\nta9 range or a plateau1 or ! s9k+ ( critical portions ( ! sea-bottom4 ,! developm5t ( prov9cial & cosmopolitan faunas4#cja--;,if a region is isolat$ f o!r regions by ! cutt+ (f ( all ready means ( int]migration1 z by ! =mation ( an isl& f :at _h be5 a p59sula1 or ( an inl& sea f :at _h be5 a bay1 ! flora & fauna are develop$ by !mselves )\t mu* influx ( o!r =ms1 & h5ce become local or prov9cial4 ,?is is usually m m>k$ 9 ! case ( ! fauna ?an ( ! flora1 because ! latt] has m ample means ( disp]sion1 on ! :ole1 & s ! fauna may = conv5i5ce be tak5 z ! type4 ,a good illu/ration is ! native fauna ( ,au/ralia :i* 0 once connect$ ) ,asia1 b has long be5 sep>at$ f x4 ,previ\s to importations by man1 ?is cont95t _h a v peculi> & di/9ct fauna1 desc5d$ f its ,mesozoic inhabitants4 ,mo/ ( ! isolat$ isl&s h peculi> faunas1 b 9 _m cases !y 7 isolat$ f ! beg9n+1 hav+ be5 built up by volcanic action f ! bottom ( ! sea1 & _! faunas are due to ! accid5ts ( transportation & to ! developm5t ( ^! sporadic =ms 9 isolation4#cjb ,x is evid5t t :5ev] any geographic *ange introduces a b>ri] to migration1 ! faunas ( ! dissev]$ portions w1 9 all probability1 develop along diff]5t l9es1 & w div]ge into prov9cial faunas4 ,on ! o!r h&1 any geographic *ange t unites areas & leads to int]migration1 t5ds to a community ( fauna or to cosmopolitanism4 ,^! t5d5cies h be5 m>k$ly felt all ?r\gh ! geologic ages1 & con/itute "o ( ! mo/ vital features ( _! hi/ory4 ,:5 cont95ts are connect$1 _! faunas int]m+le & ! ex*ange gives rise to common =ms4 ,!y t5d to bl5d into "o great fauna except s f> z ! local diff]5ces develop ^? m9or assemblages previ\sly discuss$4 ,:5 cont95ts are sep>at$1 !y t5d to develop peculi> faunas1 z d isl&s1 b on a l>g] scale4 ,?is is v obvi\s 9 ! case ( ! l& life1 b ne$s m special /atem5t = ! oceans4 ,! oceans con/itute a s+le body ( wat] ) ample connections & /irr$ by a sy/em ( con/ant circulation4 ,probably ?is has be5 true = mo/ ( kn[n geologic "t4 ,a s+le cosmopolitan fauna ( ! l>ge/ type might be expect$4 ,?is is 9 a measure realiz$ 9 ! pelagic fauna ( ! op5 ocean1 ?\gh ?is is some:at modifi$ by ! climatic zones4 ,b ! m>9e faunas t are fossiliz$ 9 ! kn[n /rata1 & h mo/ geologic int]e/1 are1 ) r>e exceptions1 n ^? ( ! op5 ocean1 b ^? ( ! %ore zones & ( ! %all[ seas4 ,n[1 al?\gh ^! %ore belts & %all[ seas are broadly connect$ ) ! great ocean body1 & are usually reg>d$ z a "p ( x1 !y are s+ul>ly sep>at$ f x1 or r !y are s+ul>ly sep>at$ by x1 s f> z ! life dep5d5t on %all[-wat] conditions is conc]n$4 ,to ?is life1 ! deep sea is a b>ri] n q z effective z ! l&1 b /ill a b>ri]4 ,! key to ?is important fact may be f\nd 9 a consid]ation ( ! v]tical di/ribution ( life4 ,! great horizon ( life is at or ne> ! contact zone ( ! atmosph]e ) ! hydrosph]e & li?osph]e4 ,life decl9es ) increas+ altitude1 p>tly because ( ! l[]+ temp]ature1 & p>tly because ( ! increas+ t5uity ( ! atmosph]e4 ,! successive *anges ( plant & animal life ) ! asc5t ( m\nta9s & plateaus is famili>4 ,life decl9es 9 desc5t into ! sea *iefly f lack ( light1 & second>ily f ! l[]+ ( temp]ature4 ,light is ess5tial to ! =mation ( *lorophyll &1 ?r\gh x1 ( all o!r organic comp\nds4 ,! *lorophyll-=m+ plants are1 !re=e1 limit$ to su* dep?s z are p5etrat$ by ! rays necess>y = ! photosyn!sis ( organic matt]4 ,vision is cut (f )9 #bjj to #cjj feet1 & mo/ plant gr[? takes place above t dep?4 ,photographic effects become feeble or inappreciable at #ajjj to #abjj feet4#cjc ,! photosyn!sis ( plants is *iefly aid$ by ! l[] & middle "p ( ! spectrum1 :ile ! ord9>y photographic "w is *iefly done by ! upp] end1 s t ! photographic limit is bel[ ! photosyn!tic limit4 ,microscopic plants are sometimes f\nd l[] ?an ^! limits1 b !y may h be5 c>ri$ bel[ _! work+ limits by curr5ts or o!r incid5tal ag5cies4 ,= all g5]al purposes1 ! limit+ dep? ( liv+ c>bon-comp\nd+ plants may be set at #ajj fa?oms1 z a g5]\s figure--ab\t ! av]age dep? ( ! bord] ( ! cont95tal %elf--:ile ! va/ majority fl\ri% only 9 ! upp] ?ird ( ?is dep?4 ,life does n cease "h1 = ! products ( ?is surface-life s9k to great] dep?s & are f$ ^u by =ms ( sea animals t h become adapt$ to ! d>k & cold abyss ( ! ocean4 ,obvi\sly1 ^! deep-sea =ms are a v di/9ct type ( life1 & con/itute a fauna ( ! mo/ pron\nc$ k9d1 ! abysmal fauna4 ,ano!r di/9ct fauna occupies ! op5-ocean surface1 ! pelagic fauna4 ,/ill a ?ird fauna occupies ! %all[-wat] tract1 ^: bottom lies )9 ! light zone--! photoba?ic zone--& embraces ! animals t are dep5d5t on ! plants ( ?is zone1 or on its light & w>m?1 & t are m or less fix$ to ! bottom or conf9$ to ! zone because _! food is !re4 ,! physical plane ( dem>kation betwe5 ! surface or pelagic fauna & ! abysmal fauna is mu* m di/9ct & m fundam5tal ?an any t is f\nd 9 asc5d+ above ! surface ( ! sea4 ,! habitat ( ! %all[-wat] fauna is limit$ bel[ by ! d>kness1 limit$ above by ! wat]-surface1 limit$ at "o side by ! l&1 & limit$ on ! o!r side by ! deep sea4 ,x is hemm$ 9 v]tically betwe5 two planes only a few hundr$ feet ap>t4 ,lat]ally1 x is conf9$ to a n>r[ belt ab\t ! bord]s ( ! cont95ts & to ! m or less l&-girt epicont95tal seas4 ,its v]tical limits are fix$1 b its lat]al ext5t v>ies ) ! relations ( ! sea to ! surface ( ! cont95tal plat=ms4 ,?is v>iation pr(\ndly affects ! developm5t ( ! fauna4 ,:5 a major de=mation ( ! e>? takes place :i* increases ! capacity ( ! oceanic bas9s1 ! wat] is drawn d[n into !m m fully1 & correspond+ly retreats f ! cont95tal %elf4 ,! %ore is ?us c>ri$ out t[>d or to ! bord] ( ! %elf1 or ev5 p]haps d[n to "s l9e on ! abysmal slope4 ,9 ei!r case1 ! zone ( %all[ wat] suit$ to ! photoba?ic life is n>r[$1 & at po9ts x may be practically cut 9 two4 ,!re are1 h[ev]1 %elves & tracts t 7 bel[ ! light zone be=e1 :i* n[ are br\ght )9 x by ! l[]+ ( ! sea-level4 ,into ^!1 z into h>bors ( refuge1 ! life migrates s f> z x may4 ,b ^! tracts are less preval5t & cont9u\s ?an ! typical cont95tal %elf1 & "u ! conditions suppos$ !y w\ld be b imp]fectly connect$ ) ea* o!r by available %all[-wat] tracts4 7,! /eep %elv+ %ore tracts1 al?\gh furni%+ a %all[-wat] connection possibly available = "s species1 w\ld be unsuit$ to o!rs &1 "u c]ta9 conditions ( ! sea-curr5ts1 w\ld be an effective b>ri]47 ,to ^! limit$ tracts1 !re=e1 ! life ( ! photoba?ic type is re/rict$ & measurably isolat$1 & develops into local & prov9cial faunas4 ,aft] a de=m+ movem5t has ceas$1 ! sea%ore habitually advances1 develop+ a new cont95tal %elf1 & 9 "t new epicont95tal gulfs & seas4 ,9 ?is x is assi/$ by ! erosion ( ! cont95t & ! fill+ ( ! sea1 & probably by ! sl[ settl+ ( ! cont95ts4 ,z ! sea-%elf broad5s1 ! isolat$ tracts1 ! h>bors ( refuge1 become connect$1 & migration is facilitat$4 ,:5 ! connection becomes g5]al & broad1 & :5 epicont95tal seas h =m$ available tracts across ! face ( ! cont95ts1 a g5]al comm+l+ ( faunas foll[s1 & a cosmopolitan fauna results4 ,9 ! same way1 b m obvi\sly1 :5 ! l& is ext5d$ & connection betwe5 ! cont95ts becomes g5]al1 !re is migration & comm+l+ ( ! l& faunas & floras1 & cosmopolitan communities are ! result4 ,x is obvi\s t ! developm5t on ! l& is ! reciprocal ( t 9 ! sea4 ,:5 ! seas are ext5d$ & _! life is t5d+ t[>d cosmopolitanism1 ! l&s are dissev]$1 & _! life is t5d+ t[>d prov9cialism1 & vice v]sa4 ,:51 h[ev]1 ! l& is greatly ext5d$1 x is usually acc5tuat$ by m\nta9 ranges1 & o!r products ( ! de=mation :i* ext5d$ x1 & ^! =m b>ri]s4 ,des]t wa/es & o!r inhospitable tracts1 & ev5 glaciation1 are liable to develop z second>y consequ5ces1 & to int]pose b>ri]s1 & h5ce ! cosmopolitanism ( ! l&-life is liable to be less complete ?an t ( ! sea-life4 ,re/rictive & expansional evolution4--,x is obvi\s f ! la/ discussion t if ! picture ( ! e>?'s movem5t above drawn be true1 ! areas available = p>ticul> classes ( life may v>y greatly f age to age4 ,at times ! %all[-wat] sea-life may be =c$ to retreat into a v n>r[ tract on ! bord] ( ! l&1 & into *ance expansions "h & !re4 ,9 be+ cr[d$ into ?is limit$ tract1 p]haps also less adapt$ = a habitat on acc\nt ( ! *ange1 ! life is subject$ to sev]e competition & to h>d conditions1 & mu/ exp]i5ce 9 an int5sifi$ degree ! effects ( ! /ruggle = exi/5ce4 ,:atev] ( evolution>y pot5cy !re may be 9 su* a /ruggle "u su* re/rictive conditions %\ld be reveal$ 9 ! modifications ( ! fauna t ensu$4 ,on ! o!r h&1 :5 ! %all[ seas are g5]ally ext5d+ !mselves ^u ! l& & ! l& is be+ base-level$1 & ?us adapt$ to %all[ subm]g5ce1 ! %all[-wat] life enjoys an enl>g+ realm1 & %\ld reveal ! effects ( evolution "u expansional conditions4 ,9 af=d+ a comp>ison betwe5 ^! opposite & alt]nat+ phases ( re/rictional & expansional evolution1 geology makes "o ( its great contributions to ! ext]nal causes & conditions ( organic evolution4 ,^! w come "u repeat$ consid]ation 9 ! hi/orical *apt]s4 ,,index4 ,,volume ,i4 ,abbot1 ,m4 ,l4 7& ,humphreys1 ,a4 ,a471 #ajf1 #bjb ,abrasion1 by ice1 #bha by /reams1 #aai by waves1 #cdb by w9d1 #ch ,abysmal fauna1 #fga ,abysmal sea1 #cbf ,accretion hypo!sis1 int]nal temp]ature on1 #efd1 #efg recomb9ation ( mat]ial on1 #efh ,act9olite1 #ddg1 #dfj ,adams1 ,f4 ,d41 #dgd ,adju/m5t ( /reams1 /ructural1 #adf1 #aej topographic1 #afb1 #afc1 #aig ,adobe1 #dfg ,agassiz1 #cff1 #fjd ,agassiz1 ,l41 #cba1 #cbb1 #cbc1 #cff ,agate1 #dfj ,agate /ructure1 #dcf ,agglom]ate1 #dcd1 #dfg ,aggradation1 by ice1 #bih by /reams1 #b1 #agg by w9d1 #be 9 sea1 #ccc1 #cee ,aggrad+ /reams1 *>act]i/ics1 #agi1 #ahg ,airy1 ,sir ,g41 #cda ,alaba/]1 #dfj ,albite1 #djj1 #dfj ,alf]ric rocks1 #ded ,alg1 geologic contribution (1 #fec influ5ce on precipitation1 #bbe ,alkalicalcic rocks1 #deh ,alluvial cone1 #aha-c gr[?1 #aha levees1 #ahb ,alluvial deposits1 #agg-if ,alluvial fans1 #aha-c ,alluvial pla9s1 #aha1 #ahd-if mat]ial (1 #aif orig9 (1 #ahd1 #ahe pi$mont1 #ahc topography (1 #aif ,alluviation1 #aha1 #aif1 #dfg ill-def9$1 #ahc ,alp9e glaci]s1 #bea ,alps1 cru/al %ort5+ involv$ 9 =mation (1 #edi1 #egf /ructure1 #ejd1 #ejg ,amb]1 #fdf ,ame?y/1 #dfj ,amphibole1 #dfj ,amphiboles1 #djj ,amygdaloid1 #daa1 #dfg ,analcite1 #dfj ,analyses1 ,am]ican riv]-wat]s1 #ajg ,am]ican spr+-wat]s1 #bce ra9-wat]s1 #ajg riv]-wat]s1 #ajf1 #ajg1 #ajh sea-wat]1 #cbd wat]s ( enclos$ lakes1 #cib ,anamorphism1 #ddf ,&alusite1 #dfj ,&es1 sn[-l9e 91 #bdf ,&es9e1 #djj1 #dfj ,&esite1 #dfg ,angiosp]ms1 #feg ,anhydrite1 #dfj ,animal k+dom1 geologic contribution (1 #feh-fc synopsis (1 #fei ,anor?ite1 #dfj ,anor?osite1 #dfg ,ant>ctica1 sn[-l9e 91 #bdf ,antec$5t /reams1 #afi1 #agc ,an?racite1 #dbf1 #dfj ,anticl9al valleys1 #aei ,anticl9e1 #ejd plung+1 #aee1 #aeg1 #ejf ,anticl9oria1 #ejd ,antimony1 #dfj ,apatite1 #dfj ,aphanite1 #dea1 #deb1 #dfg ,aplite1 #dae ,appala*ian ,ris]1 #agc ,appala*ians1 cru/al %ort5+ due to fold+1 #edi ext5t ( piracy 91 #afi peculi>ities ( dra9age1 #afi rejuv5ation ( /reams 91 #afe /ream adju/m5t 91 #adg ,aque\s rocks1 #dfg ,aragonite1 #dfj ,ar*ean complex1 #ah ,ar* ( e>?'s cru/1 /r5g? (1 #ehb ,ar*eozoic era1 #ai ,ar5ace\s rocks1 #dfh ,arid regions1 erosion 91 #aca ,argillite1 #ddh1 #dfh ,arkose1 #dbb1 #dfh1 #fde ,artesian wells1 #bdb ,ar?ropoda1 geologic contribution (1 #ffb ,asid]ites1 #e ,asphaltum1 #dfj ,a/]oids1 #ffa ,a/ronomic geology1 #a1 #b ,atlantic coa/al pla91 #ehg ,atmosph]e1 #e affect$ by life1 #fci1 #fdj c>bonation by1 #dc *emical "w (1 #da-dc evaporation & precipitation1 #ej fluctuations 9 composition1 #fci-dd geologic activity (1 #f1 #ba-dc mass & ext5t1 #f me*anical "w (1 #ba-da oxidation by1 #db !rmal effects (1 #g ,atmosph]ic electricity1 #dc1 #eb ,atmosph]ic precipitation1 am\nt (1 #ea ,augite1 #djj1 #dbi1 #dfa ,augitite1 #dfh ,autocla/ic rock1 #ddd ,au/ralia1 fauna (1 #ffh ,babb1 ,c4 ,c41 #ajg ,bad-l&s1 #ic1 #acj ,badg] ,m\nta91 #bca ,ba91 ,h4 ,f41 #fg1 #dgd ,b>badoes e>?1 #ffa ,b>ite1 #dfa ,b>ri]1 !1 #cef ,b>s1 #aha1 #ceg ,b>us1 ,c>l1 #efb1 #efc ,basalt1 #dag1 #deb1 #dfh ,basaltic columns1 #dag ,base-level1 #fj1 #fb1 #hb1 #afh ,cretace\s1 #afi ,kiltat9ny1 #afh tempor>y1 #hd ,basem5t complex1 #ah ,ba?oli?s1 #ejj1 #eib ,bay\1 #aib ,bay\ lakes1 #aic ,bays1 orig9 (1 #cca1 #ccb ,bea*1 !1 #cee ,beauxite1 #dfa ,beck1 ,r41 #dgd ,beck]1 ,g4 ,f41 #dgd ,b]gs*rund1 #beh ,b]t91 #cbc ,b]yl1 #dfa ,bighorn ,m\nta9s1 lat]al mora9es 91 #cjb ,biotite1 #djj1 #dfa ,bis*(f1 ,gu/av1 #ajh ,bismu?1 #dfa 8,bitt]n10 #cgg ,bitum51 #dfa ,bitum9\s coal1 #dbf1 #dfh ,blake1 ,w4 ,p41 #dgd ,blan=d1 ,w4 ,t41 #bh1 #bjc ,blood ra91 #be ,blue mud1 #chj ,bone b$s1 #ffc ,bonneville lake1 #cfj ,bonneville %ore1 #ceb ,bottom-set b$s1 #bjb ,b[ld]s1 #dfh ,bra*iopods1 geologic contributions (1 #ffb ,brahmaputra delta1 #bjc ,brann]1 ,j4 ,c41 #dhi ,break]s1 #cda =ce (1 #cdd ,breccia1 #dbc1 #dcd1 #dfh ,britann>e1 #dei ,bronzite1 #dfa ,bryozoans1 geologic contributions (1 #ffb ,buckley1 ,e4 ,r41 #dh1 #ej1 #bba ,buhr/one1 #dfh ,burton 7& ,milne1 ,j471 #fcf ,buttes1 #adb ,bysmali?s1 #ejj1 #eib ,calc>e\s spr+s1 #bce ,calc>e\s tufa1 #cij ,calcimiric rocks1 #deh ,calcite1 #dfa ,calc-s9t]1 #dfh ,calumet & ,hecla m9e1 temp]ature 91 #efi ,calv91 ,s41 #hh1 #bjd1 #cgc1 #chi ,campbell1 ,m4 ,r41 #afg1 #aga1 #agc ,camph5e1 #fdf ,cannel coal1 #dfh ,canoe-%ap$ valleys1 #aee ,canyons1 #id-ajj ,colorado1 #ih1 #bcc ,niag>a1 #ii ,yell[/one1 #ajj ,c>bonation1 #dc1 #dbi ,c>bon dioxide1 am\nt 9 air1 #e1 #fdj & plant-life1 #ffe climatic effects (1 #fdc loss (1 #fdj supply (1 #fah1 #fdj ,cascade1 #bfd ,cassit]ite1 #dfa ,catl9ite1 #dfa ,causes ( cru/al movem5t1 #eea-eeg ,cav]ns 7see ,caves7 ,caves1 #adc1 #bbg-bca deposits 91 #bbh ,mammo?1 #bbg sea1 #cej ,wy&otte1 #bbg ,caz91 ,f4 ,m4 ,f41 #dgd ,cem5tation1 effect$ ?r\gh *emical precipitation1 #bbb1 #bbe1 #bbf effect$ ?r\gh evaporation1 #db ,cephalopods1 geologic contributions (1 #ffb ,*alc$ony1 #dfa ,*alk1 #dfh1 #ffj ,*all5g] deep1 #ehg1 #ehh ,*alybeate spr+s1 #bce ,*amb]l91 ,t4 ,c41 #bc1 #bdb1 #bef1 #cbb1 #dgg1 #efe1 #ffh ,*anges ( level1 #ecg-eea caus$ by e>?quakes1 #ecf causes (1 #eea-eeg effect on dra9age1 #afa sea v]sus l&1 #ech ,*anges ( temp]ature1 conditions affect+1 #de effect on rocks1 #dd1 #di int]nal 7see ,int]nal temp]atures7 ,*>le/on e>?quake1 #ecj ,*att] m>ks1 #bhd ,*emical comb9ation1 cause ( cru/al movem5t1 #eef ,*emical deposits1 #bbb-bf 9 deep sea1 #chc 9 lakes1 #cia 9 %all[ sea1 #cgd-cgh ,*emical "w ( atmosph]e1 #da-dc ,*emical "w ( life1 #fch-df ,*]t1 #dbf1 #dfh ,*ia/olite1 #dfa ,*imney rocks1 #cej ,*lorite1 #dfa ,*lorite s*i/1 #dfh ,*loritic rock1 #dca ,*romite1 #dfa ,*rysolite1 #dfb ,*rysotile1 #dfb ,c9d]-cones1 #fjh ,c9d]s1 #dje ,cirques1 #bhf ,cl>ke1 ,f4 ,w41 #cif1 #egc ,classification ( rocks1 #ddi new sy/em (1 #dea ,cla/ic rock1 #dfh ,clay1 #dfh ,clay iron/one1 #dfh ,claypole1 ,e4 ,w41 #edi ,cleavage planes & erosion1 #abe developm5t ( 7see ,slate & ,s*i/7 ,cliff glaci]1 #bef ,climate1 influ5ce on erosion1 #abg-acb ,climatic effects ( c>bon dioxide1 #fdc ,climatic effects ( life1 #fdc ,climatic effects ( wat] vapor1 #fdc ,cl9k/one1 #dfh ,cl9omet]1 #eja ,coal1 #dfh ,coa/-l9es #cec1 #cfc-f effect ( gradation on1 #ccc1 #cfc effect ( subsid5ce on1 #cbi1 #ccb effect ( vulcanism on1 #ccb-cc =ms (1 #cbi1 #ccc1 #cfc1 #cfd ,coa/ ranges1 cru/al1 %ort5+ due to fold+ (1 #edi ,coa/s1 natural bridges on1 #cea ,cobb1 ,c41 #cf ,cl5t]ata1 geologic contribution (1 #ffa ,coll9s1 ,a4 ,l41 #dgd ,colorado1 ,canyon (1 #ih1 #bcc ,columbia ,riv]1 #aga ,column> /ructure1 #dih-ejj effect on wea!r+1 #aec1 #aed ,common spr+s1 #bce ,compression jo9ts1 #ead ,concave tracts ( cru/1 #ehe1 #ehf ,concretions1 #dch1 #dfh1 #dij ,cones1 c9d]1 #fjh composite1 #faj =mation (1 #fjh geys]1 #bcg lava1 #fjh spatt]1 #faj tufa1 #faa ,configuration ( coa/s1 #cbi1 #ccj1 #cca1 #ccb1 #ccc1 #cec1 #cfc-f ,con=mability1 #ae ,conglom]ate1 #dbc1 #dcd1 #dfh1 #dhg ,cont95tal glazi]s1 #bea ,cont95tal plat=ms1 #aa relief (1 #aa ,cont95tal segm5ts1 size (1 #edg ,cont95tal %elf1 #aa ,cont95t-=m+ movem5ts1 #edd ,cont\r int]val1 #ca ,cont\r l9es1 #ca ,convection hypo!sis1 int]nal heat on1 #eei !rmal di/ribution on1 #eei ,cooley1 ,e4 ,g41 #aie ,coon ,butte1 #eif ,copalite1 #fdf ,coprolites1 #fdf ,coqu9a1 #dfi ,coral mud1 #chj ,corni%1 ,v41 #bf1 #bh1 #bi ,corrasion1 #aaj1 #aac by glaci]s1 #bha-hf by /reams1 #aai by waves1 #cdb-di by w9d1 #ch effect ( s$im5t on1 #abj ,cor!ll1 ,e4 ,l41 #bjb ,cosmopolitan faunas1 #ffh ,c\lt]1 ,j4 ,m41 #ffg ,coves1 #adc ,c[les1 ,h4 ,c41 #ce1 #ffg ,cr$n]1 ,h41 #ce1 #ech ,creep1 #bca ,cretace\s base-level1 #afi ,crevasses1 #bfd ,cr9oids1 #ffa ,croll1 ,james1 #cbb1 #cbc1 #cci ,crosby1 ,w4 ,o41 #eac ,cross-b$d+1 #cgc1 #dhg ,cross-curr5ts1 9 /reams1 #aag ,cross1 ,:itman1 #dab1 #dea1 #ece1 #egc ,croton ,riv]1 mat]ial 9 solution 91 #ajh ,cru/al movem5ts1 #ebf-ehi causes (1 #eea-eg diff]5tial ext5t (1 #edh due to *emical *anges1 #eef due to cohesion & cry/allization1 #eed due to diffusion1 #eee e>?quake1 #ebg-cc m9ute & rapid1 #ebf p]iodicity (1 #eag1 #eci resi/ance to1 #eeg sl[ & massive1 #ecg-ei ,cru/al %ort5+1 #edh-ea ,cru/ ( e>?1 #ac dep? (1 #ad v>ieties ( rock 91 #ad ,cry/all9e rocks1 types (1 #af ,cry/allites1 #djg ,cry/allization ( lava1 #dja-b /ages (1 #djc ,cry/als1 enl>gem5t (1 #dce ,cut-&-fill1 #aij1 #aic ,cut-(f1 #aia ,cycle ( erosion1 its /ages1 #hj def9ition (1 #hb recognition (1 #afd ,cy/oids1 #ffa ,dacite1 #dfi ,dale1 ,t4 ,n41 #eje ,daly1 ,r4 ,a41 #fca ,dana1 ,j4 ,d41 #bjc1 #cdj1 #cdi1 #eaa1 #edc1 #fjd1 #fcf ,daniell1 ,a41 #egb1 #egc ,danube ,riv]1 delta (1 #bjb mat]ial 9 solution 91 #ajh s$im5t c>ri$ by1 #ajg ,d>ton1 ,n4 ,h41 #da1 #ej1 #ec1 #id1 #ace1 #aed1 #did1 #egj ,d>w91 ,c41 #fjd1 #fcf1 #ffe ,d>w91 ,g4 ,h41 #ecd1 #efa1 #egf1 #egi1 #ehc1 #fjd ,daubree1 ,g4 ,a41 #fbf ,davis1 ,b4 ,m41 #bbe ,davis1 ,w4 ,m41 #hc1 #aei1 #afd1 #agj1 #ahh1 #bjb1 #bjd #baj #cdi1 & ,%al]1 ,n4 ,s41 #bef ,davis1 ,c4 ,a41 #fee ,davison1 ,c41 #ebg1 #ech1 #efa ,de,beaumont1 ,eli1 #cbc ,dec>bonation1 #dbi1 #dcj ,de,charpentier1 ,j41 #cba1 #cbb1 #cbc ,deeley1 ,r4 ,m41 #cbb ,deep-sea deposits1 #cfh1 #cgh-hf *emical1 #chc-hf extra-t]re/rial1 #cha inorganic1 #chj manganif]\s1 #chd organic1 #chb ,deep-sea fauna1 #fgj ,deposition1 by glaci]s1 #bih-cje by /reams1 #agg-bjd by %ore curr5ts1 #cee by und]t[1 #cee by waves1 #cee-fc by w9d1 #be-cg ,de=mation ( e>?'s cru/1 #ebf-hi causes (1 #eea-eg1 #egd-hi relation to di/ribution ( volcanoes1 #fja1 #fjd1 #fbg1 #fbi ,de=mation ( ice1 #cab ,degradation1 #b by wat]1 #eh-agg rate (1 #aje ,de ,launay1 ,l4 ,c41 #dgd ,delesse1 ,a41 #bba1 #cda ,delessite1 #dfb ,dells ( ! ,wiscons91 #aeb ,delta lakes1 #bjd ,deltas1 #aha1 #aih-bjd bottom set b$s1 #bjb developm5t1 #aii =e-set b$s1 #bjb fossil1 #bjc 9 tidal seas1 #bjb ( ! ,ganges & ,brahmaputra1 #bjb ( ! ,hoang-,ho1 #bjb1 #bjc ( ! ,mack5zie1 #bjb ( ! ,mississippi1 #aig1 #bjb ( ! ,nile1 #bjb ( ! ,po1 #bjb ( ! ,rhone1 #bjc ( ! ,yukon1 #bjb rate ( gr[?1 #bjb %ape1 #bja /ructure1 #aih1 #aii top-set b$s1 #bjb ,d5sities )9 ! e>?1 on ,laplace's law1 #efd ,d5udation & volcanic action1 #fbg ,deoxidation1 #dbg ,deposition ( m9]al matt] f solution1 #ej1 #bbe1 #dbh at surface1 #ej1 #bbd by gr\nd-wat]1 #bbd1 #dbh 9 lakes1 #chg 9 sea1 #cge1 #chc ,deposition ( s$im5t1 #ff by riv]s1 #agg-bjd by w9d1 #be-ch 9 ocean1 #cee-fc1 #cfh-hf ,deposition ( drift1 at edge ( glaci]s1 #bii at end glaci]s #bii b5ea? ice1 #bih ,deposits1 deep-sea1 #cfh1 #cgh-hf hot spr+s1 #bcg1 #bda lacu/r9e1 #chg littoral1 #cfi made by animals1 #feh-fc made by ,ar?ropoda1 #ffb made by ,bryophytes1 #fef made by ,e*9od]mata1 #ffa made by ice1 #bih-cje made by ,mollusca1 #ffb made by ,molluscoidea1 #ffb made by ,protozoa1 #ffj made by ,pt]idophytes1 #feg made by plant k+dom1 #feb-eh made by riv]s1 #agg-bjd made by ,sp]matophytes1 #feg made by ,?allophytes1 #fec made by ,v]mes1 #ffb made by ,v]tebrata1 #ffc made by w9d1 #be-ch %all[-wat]1 #cfi-gh silici\s1 #bcg1 #bda1 #dbe tufa1 #bcg1 #bda1 #dgc1 #faa1 #fec ,depression & volcanic action1 #fbi ,dep? ( ! ocean1 #g greate/1 #h1 #edh ,diabases1 #dah1 #dca1 #dfi ,diallage1 #djj1 #dfb ,dia/rophism1 #b1 #cbi1 #ebf effect on coa/ l9es1 #cbi ,diatom ooze1 #chj1 #chb1 #dbe1 #dfi ,diffusion1 9 e>?'s int]ior1 #eee cause ( cru/al movem5t1 #eee ,dikes1 #eia effect on topography1 #adc s&/one1 #ead ,dill]1 ,j4 ,s41 #bi1 #ead ,diorites1 #daf1 #deb1 #dfi ,dip1 #eja quaquav]sal1 #ejd ,dip-fault1 #ebb ,di,rossi1 ,m4 ,s41 #ecg ,displacem5t ( fault1 #ead ,disruption ( rock1 due to *anges ( temp]ature1 #dd1 #di by c>bonation1 #dc by hydration1 #aaa ,di/ributive fault1 #eai ,divides1 p]man5ce (1 #fi ,docalcic rocks1 #deh ,dodge1 ,r4 ,e41 #bjd ,d(emane1 #dee ,d(emic rocks1 #ded ,d(]r\s rocks1 #dei ,dohemic rocks1 #deg ,dol5ic rocks1 #def ,dol]ites1 #dag1 #deb1 #dfi ,dolomites1 #dbd1 #dfi ,domagnesic rocks1 #dei ,domalkalic rocks1 #deh ,domes ( cru/1 /r5g? (1 #eha1 #ehb ,domilic rocks1 #ehb ,domiric rocks1 #deh ,domirlic rocks1 #deh ,domitic rocks1 #deg ,dopolic rocks1 #def ,dopotassic rocks1 #deh ,dopyric rocks1 #deg ,doqu>ic rocks1 #def ,dosalic rocks1 #ded ,dosodic rocks1 #deh ,dotilic rocks1 #deg ,dra9age1 effect ( *ange ( level on1 #afa mature1 #hf ( glaci]s1 #bgc old age1 #hi y\?ful1 #hf ,dreikant]1 #dj ,drift1 #bhg1 #dfi composition (1 #cjd deposition (1 #bih-cje we> (1 9 transit1 #bih ,drygalski1 ,e4 von1 #cbb ,dump mora9e1 #cja ,dune areas1 topography (1 #cb ,dunes1 #bd-cg di/ribution (1 #ce effect ( vegetation on1 #bi =mation (1 #bf migration (1 #cc %apes (1 #bf slopes (1 #bi ,du/1 volcanic1 #bb1 #bc w9d-bl[n1 #bb ,du/-wells1 #bfi1 #bhj ,dutton1 ,c4 ,e41 #acb1 #ecd1 #egd1 #fcf ,dynamic geology1 #a ,e>?1 !1 z a planet1 #b con/itution1 #e cru/1 #ac de=mation (1 #ebf dep5d5ce on sun1 #d di/ance f sun1 #c incl9ation ( axis1 #c int]ior (1 #ad1 #eei int]nal heat1 #eei-gd motions1 #c orbit1 #c tremors ( surface1 #ebf w>p+s ( cru/1 #ebf-hi ,e>?quakes1 #ebg-ecg causes (1 #ebg de/ruction ( life by1 #ecf di/ribution (1 #ecc de/ructive effects (1 #ecj epic5tra (1 #eca foci (1 #ebg gase\s emanations dur+1 #ecc geologic effects (1 #ecd-ecg ,e>?quake vibrations1 #ebf amplitude (1 #ebi ,*>le/on1 #ecd ,lisbon1 #ece sequ5ces (1 #ecc ,e>?'s cru/1 composition (1 #ad1 #cif w>p+s (1 #ech-eea ,ea/man1 ,c4 ,r41 #feh ,e*9od]mata1 geologic contributions (1 #ffa ,e*9oids1 geologic contributions (1 #ffa ,economic geology1 #a ,effloresc5ce1 #db ,elolite1 #dfb ,electricity1 atmosph]ic1 #dc *emical effects (1 #dc geological effects (1 #dc1 #eb ,ells1 ,r41 #ddc ,emmons1 ,s4 ,f41 #dgd ,emmons1 ,w4 ,h41 #dgd1 #egc1 #ehe ,englacial drift1 #bhb ,enl>gem5t ( cry/als1 by second>y gr[?1 #dce ,en/atite1 #djj1 #dfb ,eolian rocks1 #dfi ,epeirog5ic movem5ts1 #ecg ,epicont95tal seas1 #aa1 #cbf ,epidote1 #dca1 #dfb ,equiset1 geologic contribution (1 #feg ,eras1 #ag-ai ,erosion1 affect$ by rotation1 #aid analysis (1 #aaj base-level (1 #fj by glaci]s1 #bha-bhf by ra91 #eg by riv]s1 #ef-agg by und]t[1 #cdb1 #cdf by waves1 #cdb-cdi by w9d1 #ch conditions affect+ rate (1 by glaci]s1 #bhc conditions affect+ rate (1 by runn+ wat]1 #abc cycle (1 #hj1 #hb1 #afd 9 arid regions1 #aca influ5c$ by climate1 #abg1 #abh1 #abi influ5c$ by composition ( rock1 #abd influ5c$ by declivity1 #abc influ5c$ by /ructure1 #abd1 #abf influ5c$ by vegetation1 #abi1 #fdd %eet1 #ei subarial1 #eh ,erosion & cleavage planes1 #abe ,erosion & jo9ts1 #abe ,erosion by /reams 7see ,erosion by runn+ wat]7 ,eruptions1 #eia fissure1 #eic volcanic1 #eid ,esk]s1 #cjf ,etna1 #fje1 #faj dis*>ge ( /ream f1 #fcf ,evaporation1 #ej ,ev]ett1 #egh ,evolution re/rictive & expansional1 #fgb ,exfoliation1 #dd ,expansional evolution1 #fgb ,expansion & contraction1 due to temp]ature1 #dd due to wett+ & dry+1 #eb ,ext9ct lakes1 #chh ,extrusive processes1 #eij-fcg ,falb1 ,r41 #ecg ,false b$d+1 #dhg ,fault+ & vulcanism1 #fbg ,faults1 conditions (1 #eba dip1 #ebb displacem5t1 #ead di/ributive1 #eai effect on outcrops1 #ebb hade1 #ead heave (1 #ead normal1 #eag oblique1 #ebe relation to folds1 #eae rev]s$1 #eag1 #eba /ratigraphic ?r[1 #eah significance (1 #eba /rike1 #ebb ?ru/1 #eag1 #eah ,fault sc>p1 #ead ,faunas1 abysmal1 #fgj ,au/ralian1 #ffh cosmopolitan1 #ffh deep-sea1 #fgj pelagic1 #fgj photoba?ic1 #fgj ,faunas & floras1 basis (1 #ffc effect ( geographic conditions on evolution (1 #ffh ,feldsp>1 #dfb ,feldsp>-leucophyres1 #dec ,feldsp>-melaphyres1 #dec ,feldspa?ic m9]als1 #djj ,feldspa?oids1 #djj ,felsites1 #deb1 #dfi ,f5neman1 ,n4 ,m41 #cci ,f]guson1 ,a4 ,m41 #bjc ,f]ns1 geologic contribution (1 #feg ,fiords1 #bij ,fi%]1 ,o41 #efa1 #efe1 #egd1 #eha ,fissure eruptions1 #eic ,flet*]1 ,g4 7& ,deeley1 ,r4 ,m471 #cbb ,fl9ts1 #dbf1 #dfi ,floods1 #aji ( ! ,mississippi1 #ahh ,flood-pla9 me&]s1 #aij ,flood-pla9s1 #ahd-ih developm5t (1 #afe mat]ials (1 #aif ,mississippi1 #aid relation to t]races1 #bje topography1 #aif ,floras & faunas1 basis (1 #ffc effect ( geographic conditions on1 #ffh ,fl[]+ plants1 geologic contributions (1 #feg ,fl[+ wells1 #bcd1 #bdb ,fl[ /ructure ( lavas1 #daj ,fluorite1 #dfb ,fluvio-glacial "w1 #cje-g ,fold$ ranges1 di/ribution (1 #edc ,fold+ & vulcanism1 #fbh ,folds1 anticl9al1 #ejd1 #eje effect on valleys1 #aed isocl9al1 #ejd syncl9al1 #ejd ,folds & faults1 #eae ,foliation ( ice1 #bgb ,foliation ( rocks1 #ddc ,=am9if]a1 geologic contribution (1 #ffj ,=bes1 ,j4 ,d41 #bef1 #cbb ,=el1 ,f4 ,a41 #cbc1 #chf ,=e-set b$s1 #bjb ,=mation1 #dhg ,=/]1 ,w4 ,g41 #ecf 8,fossil0 deltas1 #bjc ,fossils1 #af1 #fdf a means ( correlation1 #fdg ,fossils & /ratigraphy1 #fdg ,f\qu1 ,f41 #fce1 #fcf ,fracture1 zone (1 #bai ,frank1 ,a4 ,b41 #fdb ,free/one1 #dfi ,fr5* ,broad ,riv]1 !1 #afh ,fulgurites1 #eb1 #dfi ,fungi1 geologic contribution (1 #fec ,gabbroids1 #dec ,gabbros1 #daf1 #deb1 #dfi ,gal5ite1 #dda ,ganges ,riv]1 delta (1 #bjc ,gangue1 #dfi ,ganni/]1 #dfi ,g>net1 #dfb ,g>netite1 #dfi ,gase\s emanations1 dur+ e>?quakes1 #ecc f volcanoes1 #fag ,gases 9 volcanic rocks1 #fai ,gases1 volcanic1 #fag-fbc am\nt (1 #fbj k9ds (1 #fah1 #fai proportions (1 #fbj1 #fbb s\rces (1 #fba ,ga/ropods1 geologic contributions (1 #ffb ,geantcl9e1 #eje ,gee/1 #dfi ,geikie1 ,a41 #bjc1 #bbd1 #cdd1 #ecd-ecf1 #fcf ,geodes1 #dcf1 #dig ,geognosy1 #a1 #e1 #cic-dhe ,geologic effects ( e>?quakes1 #ecd ,geologic functions ( life1 #fch ,geologic processes1 man's influ5ce on1 #fdi ,geologic "t divisions1 #ai ,geology1 a/ronomic1 #a1 #b atmosph]ic1 #b cosmic1 #a dom9ant processes (1 #b dynamic1 #a economic1 #a geotectonic1 #a1 #dhf glacial1 #b hi/orical1 #a m9+1 #a paleontologic1 #a philosophic1 #a physiographic1 #a scope (1 #a /ructural1 #a1 #dhf subdivisions (1 #a ,george1 ,r4 ,d41 #ede ,geosyncl9e1 #eje ,geotectonic geology1 #a1 #dhf-ebe ,g]b]1 ,e41 #aie ,g]l&1 #ech ,ges*iebe wall1 #cjj ,geys]ite1 #dfc1 #dfi ,geys]s1 #bcf deposits (1 #bcg ( ,yell[/one ,p>k1 #bci p]iod ( eruption1 #bdj positions (1 #bda ,gilb]t1 ,g4 ,k41 #aa1 #aaj1 #adj1 #aid1 #aih1 #bjc1 #cci1 #cee1 #chh1 #dhi1 #eif ,glacial dbris1 h[ c>ri$1 #bij nature (1 #bhf %ift+ position 9 transit1 #bib1 #bic1 #bid1 #bif1 #big ,glacial deposits1 nature (1 #cjd ,glacial erosion1 conditions influ5c+1 #bhc topographic effects (1 #bhg ,glacial motion1 #cac-cba auxili>y elem5ts (1 #cag fundam5tal elem5t (1 #cac ,glacial pluck+1 #bhb ,glaciat$ rock surfaces1 #cjd ,glaci] ice1 beg9n+ ( movem5t1 #bdh def9ition (1 #bej granul> texture (1 #bdg %e>+ (1 #cag ,glaci] movem5t1 #bei1 #cac-cbc at l[ temp]ature1 #bgi effect ( wat] on1 #cah rates1 #bfj1 #bfa views (1 #cba ,glaci]s1 alp9e1 #bed cliff1 #bef comp>$ ) riv]s1 #bfb conditions influ5c+ movem5t1 #bfa con/itution1 #cjh cont95tal1 #bea crevasses1 #bfd de=mation1 #cab dra9age (1 #bgc1 #bhj foliation1 #bdg1 #bgb evaporation1 #bgi g5]al ph5om5a1 #bef gett+ load1 #bhb gr[? (1 #cjh gr[? ( granules1 #caj1 #caa high-latitude1 #bed limits (1 #beh motion 9 t]m9al "p1 #caf movem5ts (1 #bei1 #bgi1 #cac-cbc pi$mont1 #bed pol>1 #bed rate ( movem5t (1 #bfj1 #bfa recon/ruct$1 #bef /ratification (1 #bdg /ructure (1 #cjh surface features (1 #bff temp]ature (1 #bgc-bgi ?ick5+ ( lay]s at end1 #big topography (1 #bff types (1 #bea upturn+ ( ice at ends & edges1 #bif1 #big1 #bih valley1 #bed wa/e (1 #bgc "w (1 #bdd1 #bha ,glacio-fluvial "w1 #cje-cjh ,glass1 volcanic1 #dea ,glassy rocks1 #djf ,glauconite1 #chd1 #chf1 #dfc ,globig]9a ooze1 #chj1 #chb1 #ffj ,globulites1 #djg1 #dfi ,gneiss1 #dae1 #ddf1 #ddh1 #dfi ,goo*1 ,f4 ,a4 7& ,:itfield1 ,j4 ,e471 #bcf ,gorge1 #ajj ,grad1 ,*41 #cbb ,gradation1 #b by runn+ wat]1 #ef-bab effect on coa/-l9es1 #ccd 9 ocean1 #ccd ,grade1 #fa ,grad$ pla91 #hb1 #afi ,grad$ valley1 #hc ,granitell1 #dgj ,granites1 #dac1 #deb1 #dfi ,granitite1 #dgj ,granitoids1 #dbj1 #dec ,granulite1 #dgj ,graphite1 #dbf1 #dfc ,gravitational en]gy1 #eeb ,gravitational =ce1 #eeb1 #eec ,gravity1 a cause ( cru/al movem5ts1 #eeb effect on erosion1 #aac ,gray1 ,t4 7& ,milne1 ,j471 #egh ,gre5l&1 glaci]s (1 #bdf sn[-fields (1 #bde sn[-l9e 91 #bdf ,gre5 mud1 #chj ,gre5s&1 #dgj ,gre5s& m>l1 #chf ,gre5/one1 #dai1 #dgj ,greis51 #dae1 #dgj ,greywacke1 #dgj ,gr\nd ice1 #aai ,gr\nd mora9e1 #cja ,gr\nd-wat]1 #bac-bdc affects int]nal heat1 #egj am\nt (1 #bba desc5t (1 #bac fate (1 #bba l[] limit (1 #baf movem5t (1 #bbj results (1 #bbf solution by1 #bbb1 #bbc "w (1 #bbb ,gr\nd-wat] & vulcanism1 #fce ,gr\nd-wat] level1 #ga1 #bae ,gr\nd-wat] surface1 #ga1 #bae ,guano1 #fdf ,gulf /ream1 #cff ,gullies1 gr[? (1 #fc ,gymnosp]ms1 geologic contributions (1 #feg ,gypsum1 deposition (1 #cgf1 #cgg ,hade ( faults1 #ead ,hall1 ,jas41 #eaa ,hallefl9ta1 #dgj ,halophytes1 geologic contributions (1 #ffg ,hang+ valley1 #afd1 #bij ,haynite1 #dfc ,hayes1 ,w41 #agc ,hayes1 ,w4 7& ,campbell1 ,m4 ,r471 #aga ,head erosion1 #fd ,heat1 by compression ( ice1 #caa causes cru/al movem5t1 #eeg causes (1 9 ice1 #bgh1 #bgi di/ribution (1 )9 e>?1 #eei di/ribution1 orig9al1 #eei int]nal1 ( e>?1 #eei-egj metamorphism by1 #ddf1 #ddh orig9al di/ribution (1 #eei ,heave ( faults1 #ead ,heilpr91 ,a41 #fcf ,heim1 ,a41 #bef1 #cbb1 #edi1 #egf ,hematite1 #dbe1 #ddg1 #dfc ,high-latitude glaci]s1 #bed ,himalayas1 sn[-l9e 91 #bdf ,hi/orical geology1 #a ,hoang-,ho delta1 #bjb1 #bjc ,hog-backs1 #adb ,hold51 ,e4 ,s41 #ech ,holmes1 ,w4 ,h41 #ii ,holocry/all9e rock1 #dab ,holosid]ites1 #e ,hook 7along %ore71 #cfc ,hopk9s1 ,w41 #cbb ,horizontal configuration ( coa/s1 due to deposition1 #cfc1 #cfd due to wave erosion1 #cec ,hornbl5de1 #djj1 #dfc ,hornbl5de-granite1 #dae ,hornbl5dite1 #dag1 #deb1 #dgj ,horn/one1 #dgj ,horsetails 7see ,equiset7 ,hosk9s1 ,l4 ,m41 #bai1 #eeb1 #eha ,hot spr+s1 deposits (1 #bbe ,h[ell1 ,capt41 #aga ,hudson ,riv]1 mat]ial 9 solution 91 #ajh ,hugi1 ,f4 ,j41 #cba ,hull1 ,e41 #fcf ,humphreys1 ,a4 ,a4 7& ,abbot1 ,m4 ,l471 #ajf1 #bjb ,huxley1 ,t4 ,h41 #cbb ,hyalite1 #dfc ,hydration1 #dc1 #bbb disruption ( rock by1 #aaa ,hydrophytes1 geologic contributions (1 #ffg ,hydrosph]e1 !1 #g 7see also ,gr\nd-wat] & ,ocean7 geologic activity (1 #h horizons ( activity1 #i ,hyp]/h5e1 #djj1 #dfc ,hypog5e rocks1 #dgj ,ice1 glacial 7see ,glaci]s7 gr\nd1 #aai ( lakes1 #chi ( riv]s1 #aah ,iceb]gs1 #cjg ,ice-caps1 #bdi1 #bej ,ice cry/als1 arrangem5t 9 glaci] ice1 #caa ,ice-fall1 #bfd ,icel& sp>1 #dfc ,idd+s1 ,j4 ,p41 #dab1 #dea1 #egc1 #fad1 #fcf ,igne\s rocks1 #af composition (1 #cie lead+ m9]als (1 #cii orig9 (1 #cic relations to /ratifi$ rocks1 #af /ructural features (1 #dih ,ilm5ite1 #dfc ,incru/ation1 #bbc ,infusorial e>?1 #dgj ,inorganic deposits1 9 deep sea1 #chj ,int]ior ( e>?1 #ad 7see ,vulcanism7 d5sities1 bas$ on ,laplace's law1 #efd heat (1 #efb1 #efd pressures1 #efd ,int]mitt5t spr+s1 #bce ,int]nal heat 7see ,int]nal temp]ature7 ,int]nal temp]ature1 #efb affect$ by gr\nd-wat]1 #egj at c5tre ( e>?1 #ega on accretion hypo!sis1 #efd1 #efg on convection hypo!sis1 #eei on ,laplacian hypo!sis1 #eei ,intrusions1 #eia ,iron-ore b$s1 orig91 #dbe ,iron oxide1 #djj ,iron pyrites1 #dfc ,iron/one1 #dbe1 #dgj ,irruptions1 #eia ,isocl9al folds1 #ejd ,isoseismals1 #ecb ,itacolumite1 #dgj ,italy1 lat]al mora9es 91 #cjc ,jasp]1 #dgj ,jeff]son1 ,m4 ,w41 #aic ,johnson1 ,s4 ,w41 #aji1 #aij1 #ffe ,john/on-,lavis1 ,h4 ,j41 #fcf ,jo9ts1 #eaj causes (1 #eaa1 #eca compression1 #ead effect on valleys1 #aej ,jo9ts1 t5sion1 #ead ,jo9ts & erosion1 #abe ,judd1 ,j4 ,w41 #fcf ,kaat]skill ,creek1 piracy (1 #aje ,kames1 #cjg s]p5t9e1 #cjf ,kansas1 volcanic du/ 91 #bc ,kana:a ,riv]1 #afh ,kaol91 #dfc ,katamorphism1 #ddf ,kei?1 ,a41 #ddb1 #ddd ,kelv91 ,"l1 #efj1 #ehc ,k]atophyre1 #dgj ,k]santite1 #dgj ,keyes1 ,c4 ,r41 #dgd ,kidd1 ,d4 ,a41 #cac ,kilauea1 #fje ,k+1 ,c41 #efj ,k+1 ,f4 ,h41 #bbj ,kittat9ny base-level1 #afh ,kot1 ,dr41 #ecd ,krakatoa1 #bb1 #faj1 #faa1 #fah ,kmmel1 ,h4 ,b41 #bjc ,labradorite1 #djj1 #dbi1 #dfd ,laccoli?1 #ejj1 #eib ,lacu/r9e deposits1 #chh ,lake ice1 #chi ,lake ,pep91 #agi ,lakes1 #chf-cib bay\1 #aib1 #aic *anges tak+ place 91 #chg delta1 #bjd deposits 91 #chg ext9ct1 #chh =m$ by riv]s1 #aia1 #aib1 #aih ice (1 #chi ox-b[1 #aib1 #aih ,l&slide1 #bca topography (1 #bcj ,l&slip m\nta91 #bcj ,lane1 ,a4 ,c41 #eeg1 #fcf ,lapilli1 #dgj 9 sea1 #cha1 #dje ,laplace1 ,m>quis de1 #efd ,l>amide range1 cru/al %ort5+ due to fold+1 #edi ,lat]al mora9es1 #bff1 #cjb 9 ,bighorn ,m\nta9s1 #cjc 9 ,italy1 #cjc 9 ,u9ta ,m\nta9s1 #cjc 9 ,wasat* ,m\nta9s1 #cjc ,lat]al pressure1 metamorphism by1 #ddh ,lat]ite1 #dgj ,lava cones1 #fjh ,lavas1 #fab-faf & gr\nd-wat]1 #faf consangu9ity & succession (1 #fad cry/allization (1 #djb1 #djc dep? ( s\rce (1 #faf modes ( rea*+ surface1 #fca orig9 (1 #fbc-fca rhyolitic 7fl[7 /ructure (1 #daj solidification (1 #cic temp]atures (1 #fae1 #fbf ,lavas & und]gr\nd wat]1 #fbg ,le,conte1 ,j41 #dgd1 #edi ,l5d(elic1 #def ,l5felic1 #def ,lepidolite1 #dfd ,leucite1 #dfd ,leucophyre1 #dab1 #dec ,levees1 break+ (1 #ahh m9iature1 #ahb natural1 #ahh on alluvial cones1 #ahb ,level ( no /ress1 #efa ,life1 #fch-fgb atmosph]ic effects (1 #fch-fdd *emical "w (1 #fch-fdf climatic effects (1 #fdc effect on rock decomposition1 #acj1 #fdd geologic effects (1 #fci inorganic rocks due to1 #fdf influ5c$ by environm5t1 #fff man's influ5ce on1 #fej protection aga9/ erosion1 #acj1 #fdd ,life & c>bon dioxide1 #fdj1 #fdb1 #fdc ,lightn+1 effects (1 #eb ,lignite1 #dbf1 #dgj ,limburgite1 #dgj ,lime c>bonate1 deposition (1 #cge1 #cgf ,limonite1 #dbe ,lime/one1 #cgh1 #dbd1 #dcd orig9 (1 #cgh1 #fed1 #fee /ratification (1 #dhg ,lime/one-=m+ animals1 #ffj-ffb plants1 #fed1 #fee ,lime/one s9ks1 #bbg1 #bca ,l9dgr51 ,w41 #dgd ,lip>ase1 #dei ,lip>ite1 #dgj ,lisbon e>?quake1 #ece ,li?osph]e1 #i-ai cru/ (1 #ac irregul>ities (1 #aj relief (1 #aa size & %ape (1 #i surface mantle (1 #ab ,littoral curr5ts1 #cdb ,littoral deposits1 #cfh1 #cfi1 #cgi ,littoral zone1 #cfi ,liv]worts1 geologic contribution (1 #fef ,liv+/one1 ,d41 #di ,load 7( /reams71 #agg-agi ,loess1 #bc1 #dgj ,lodge mora9e1 #cja ,loop 7along %ore71 #ceg1 #cfc ,lun> crat]s1 #eih ,lunn1 ,a4 ,c41 #eeb1 #efe1 #eff1 #efg1 #egb ,lycopods1 geologic "w (1 #feg ,lydekk]1 ,r4 7& ,ni*olson1 ,a471 #feh ,lyell1 ,sir ,*>les1 #fdi ,mack5zie ,riv]1 delta1 #bjb ,magma1 nature (1 #dja ,magnesite1 #dfd ,magnesium salts 9 sea1 #cgg ,magnetic nodules 9 sea1 #cha ,magnetite1 #dfd ,malay p59sula1 t9 ores (1 #dgh ,malasp9a glaci]1 #bed ,mallet1 ,r41 #cbb1 #ecg1 #ech1 #fbh1 #fcf ,mammo? ,cave1 #bbg ,mammo? hot spr+s1 #fed ,manganif]\s deposits1 #chd ,mantle rock1 #ab1 #dbb ,m>ble1 #ddg1 #dga ,m>casite1 #dfd ,m>9e deposits1 #cee-cfc1 #cgj-chf *emical1 #cfg1 #cge1 #chc deep-sea1 #cfh1 #cgh-chf extra-t]re/rial1 #cha littoral1 #cfh1 #cfi me*anical1 #cfi1 #chj organic1 #cge %all[-wat]1 #cfi-cgh table (1 #chj ,m>9e life1 di/ribution (1 #cbh ,m>l1 #dga 7see also ,gre5s& m>l & ,%ell m>l7 =m$ by plants1 #fee gre5-s& 7see ,gre5s& m>l7 ,m>t9ique1 #fje ,m>tite1 #dfd ,mason1 ,w4 ,p41 #ajg ,mass action1 #dgh1 #dhd1 #eed ,mature dra9age1 #hf ,mature /reams1 *>act]i/ics (1 #hf ,mauna ,loa1 #fje1 #fjf1 #fbd ,mc,connell1 ,j4 ,c41 #cac1 #cbb1 #cbc1 #edi ,mc,gee1 ,w4 ,j41 #ei1 #ebd ,me&] belt1 relation to wid? ( /ream1 #aic ,me&]s1 flood-pla91 #aij intr5*$1 #afd ( ! ,meuse1 #afd ( ! ,moselle1 #afd ( ! ,se9e1 #afd ,mean sph]e level1 #edh ,m$ial mora9e1 #bff1 #big ,m$licott1 ,h4 ,b41 #bjc ,m$ic9al spr+s1 #bce ,melaphyres1 #dab1 #dca1 #dec1 #dga ,m5accanite1 #dfd ,m5delejeff1 ,d4 7& ,moissan1 ,h471 #fdf ,m5tal elem5t1 mat]ial effects (1 #fdi ,m]rill1 ,g4 ,p41 #ce1 #aaa1 #bba ,mesas1 #adb ,mesophytes1 #ffg ,meta-diabase1 #dga ,meta-igne\s rock1 #dga ,metamorphic rocks1 #ag ,metamorphism1 #dbg1 #dcc1 #ddj1 #ddi by heat1 #ddf by lat]al pressure1 #ddh deep-seat$1 #ddi ,meteorites1 #d numb] (1 #cha ,meuse1 me&]s (1 #afd ,mica1 #djj1 #dfd ,mica s*i/s1 #ddh ,microcl9e1 #djj1 #dfd ,microlites1 #djg1 #dga ,microgranite1 #dga ,migration ( dunes1 #cc ,mill/one1 #dga ,milne1 ,j41 #ecc1 #ecg1 #ech1 #ehc 7& ,gray1 ,t471 #egh 7& ,burton71 #fcf ,m9]al matt] 9 sea1 #cbd-cbf am\nt (1 #cbe ,m9]als1 felspa?ic1 #djj1 #dfb f]romagnesian1 #djj1 #dfj =mation (1 #cig1 #fab ( igne\s rocks1 #cii li/ (1 #dfj-dfg ,m9]al spr+s1 #bce ,m9ette1 #dae1 #dga ,m9+ geology1 #a ,m9nehaha ,falls1 #acg ,mirlic rocks1 #deh ,mississippi ,riv]1 delta1 #aig1 #bjb dep? ( *annel1 #aga flood-pla91 #aid floods (1 #ahh levees (1 #ahh mat]ial 9 solution 91 #ajh s$im5t c>ri$ by1 #ajf ,mississippi flood-pla91 #aid lakes (1 #aib ,miss\ri ,riv]1 sc\r-&-fill (1 #aie ,mitic rocks1 #def ,moissan1 ,h41 #fdf ,mollusca1 geologic contribution (1 #ffb ,molluscoidea1 geologic contribution (1 #ffb ,molt5 int]ior1 lava f1 #fbd ,molt5 magmas1 nature (1 #dja ,molt5 res]voirs1 lavas f1 #fbd ,monadnocks1 #ade ,monocl9al %ift+1 #abg ,monocl9e1 #ejd ,monzonite1 #dga ,moon1 #c1 #eih ,mora9es1 dump1 #cja gr\nd1 #cjb lat]al1 #bff1 #cjb lodge1 #cja m$ial1 #bff1 #big molluscan %ells 91 #big pu%1 #cja surface1 #bff t]m9al1 #bff1 #cja types1 #cja ,moselle ,riv]1 intr5*m5t me&]s1 #afd ,moseley1 ,h41 #cbb ,mosses1 geologic contributions (1 #fef ,m\lton1 ,f4 ,r41 #efe ,m\nta9-=m+ movem5ts1 #edb ,m\nta9s1 s]ration (1 #dh1 #ej ,m\nt ,erebus1 #fjc ,m\nt ,hecla1 #fjc ,m\nt ,%a/a1 #faa ,m\nt ,t]ror1 #fjc ,movem5ts ( glaci]s1 #bei1 #bfa1 #bgi1 #cac-cbc ,movem5ts ( sea-wat]1 #ccd-cdb causes (1 #ccd-cci ,movem5ts ( ! e>?'s body1 #ebf-ehi causes (1 #eea-eeg cont95t-=m+1 #edd di/ribution 9 "t1 #ede epeirog5ic1 #ecg fold+ movem5ts1 #ede m9ute & rapid1 #ebf m\nta9-=m+1 #edb orog5ic1 #ecg p]iodic1 #edb plateau-=m+1 #edc relation ( v]tical & horizontal1 #ede sl[ & massive1 #ecg ,mud-cracks1 #dhi ,mud-fl[s1 volcanic1 #faj ,mud-ra91 #be ,mud/one1 #dga ,mgge1 ,o41 #cac1 #cbb1 #cbc ,muir glaci]1 #bei ,murray1 ,sir ,john1 #aa1 #bae1 #cbe1 #cbf1 #cfi1 #fjd1 #fee ,muscovite1 #djj1 #dfd ,n>r[s1 #ada ,natural bridges1 #aec1 #bca ( ,virg9ia1 #aef on coa/s1 #cea ,natural gases1 #fdf ,natural levees 7see ,levees7 ,natural oils1 #fdf ,nebraska1 volcanic du/ 91 #bc ,nephel9ite1 #dga ,nephelite1 #djj1 #dfd ,nevadite1 #dga ,nv1 #bdf ,new ,riv]1 #afh ,newsom1 ,j4 ,f41 #ead ,niag>a ,falls1 #aci recession (1 #aci ,niag>a ,riv]1 #abj ,ni*olson1 ,a4 7& ,lydekk]1 ,r471 #feh ,nile ,riv]1 delta (1 #bjb mat]ial 9 solution 91 #ajh s$im5t c>ri$ by1 #ajg ,nitrog5 & life1 #fdb ,nodules1 #dga ,nom5clature ( rocks1 #ddi new sy/em (1 #dea ,norite1 #dga ,normal faults1 #eag ,nor? ,am]ica1 av]age elevation (1 #ajf ,nosite1 #dfe ,novaculite1 #dga ,nummulites1 #ffa ,oblique fault1 #ebe ,obsidian1 #djg1 #dec1 #dga ,ocean bas9s1 #aa areas (1 #g connection (1 #h deposits on1 #cfh-chf relief ( bottom1 #aa topography (1 #cbf ,ocean bas9 segm5ts1 size (1 #edg ,oceanic deposits1 *emical1 #cge deep-sea1 #cfh1 #cgh-chf organic1 #cge1 #chb %all[ wat]1 #cfi-cgh ,ocean1 !1 #g1 #cbd-cib *anges 91 #cbi composition (1 #cbd dia/rophism 91 #cbi gradation 91 #ccc salts (1 #cbd volume (1 #h vulcanism 91 #ccb "w (1 #cbd-cib ,(fset ) gap1 #ebe ,(fset ) ov]lap1 #ebe ,oldham1 ,r4 ,d41 #ecd1 #ece ,oligoclase1 #djj1 #dfe ,oliv9e1 #djj1 #dfe ,omeose1 #dei ,omphacite1 #dfe ,onyx1 #dga ,oolite1 #dce1 #dga1 #dif ,ooze1 #dga ,opal1 #dfe ,ore deposits 7see ,ores7 ,o',reilly1 ,j4 ,p41 #ech ,ore regions1 orig9 (1 #dgg ,ores1 #dbh1 #dgd-dhe conc5tration by reprecipitation1 #dgi conc5tration by solution1 #dgi conc5tration by surface lea*+1 #dgh 8flaxse$10 #dig influ5ce ( rock walls on deposition1 #dhd magmatic segregation1 #dge m>9e segregation1 #dgf orig9al di/ribution1 #dge purification by lea*+1 #dgh residual conc5tration1 #dgh ,organic processes1 #fch ,organic residue1 #fdj1 #fda ,organic rocks1 #ddi1 #fdf ,orig9al heat di/ribution1 #eei-efh ,orig9 & desc5t ( rocks1 #cic-dhd ,orog5ic movem5ts1 #ecg ,or?oclase1 #djj1 #dfe ,or?ophyre1 #dga ,os>s1 #cjf ,outcrops1 effects ( faults on1 #ebb ,outwa% pla91 #cjf ,ov]load+ ( /reams1 #agg1 #agh1 #ahf ,ov]?ru/1 #eah ,oxb[ lakes1 #aib1 #aih ,oxidation1 #db1 #dbg ,ozoc]ite1 #dfe1 #fdf ,paleontologic geology1 #a ,paleontology1 #a ,p>aff9e1 #fdf ,pea/one1 #dgb ,peat1 #djf1 #dgb ,pegmatite1 #dgb ,pelagic deposits1 #cgi-chf organic con/itu5ts (1 #chb ,pelagic fauna1 #fgj ,pelecypods1 %ells (1 #ffb ,pele's1 #fah 8,pele's hair10 #djd ,pelites1 #dgb ,p5epla91 #ha1 #afi ,p5rose1 ,r4 ,a4 ,f41 ,jr41 #dgh ,p]alkalic rocks1 #deh ,p]caleic rocks1 #deh1 #dei ,p]femane1 #dee ,p]femic rocks1 #ded ,p]felic rocks1 #def ,p]f]r\s rocks1 #dei ,p]idotites1 #daf1 #dec ,p]l5ic rocks1 #def ,p]lite1 #djh1 #dec1 #dgb ,p]miric rocks1 #deh ,p]mirlic rocks1 #deh ,p]mitic rocks1 #deg ,p]olic rocks1 #deg ,p]polic rocks1 #def ,p]potassic rocks1 #deh ,p]pyric rocks1 #deg ,p]qu>ic rocks1 #def ,p]rey1 ,a41 #ecg ,p]r9e1 #ech ,p]salane1 #dee1 #dei ,p]salic rocks1 #ded ,p]sodic rocks1 #deh ,p]tilic rocks1 #deg ,petrifaction1 #bbc 8,petrifi$ turtles10 #dif ,petroleum1 #dfe ,petrology1 #a1 #cic-dhe ,petrosilex1 #dgb ,pfaff1 ,f41 #ecg ,phan]ites1 #dea ,phan]ocry/all9e rocks1 #dab ,ph5ocry/s1 #dab ,philosophic geology1 #a ,phonolite1 #dgb ,photoba?ic fauna1 #fgj ,photoba?ic zone1 #fgj ,phyllite1 #dgb ,physiographic geology1 #a ,picrolite1 #dfe ,pictotite1 #dfe ,pi$montite1 #dfe ,pi$mont glaci]1 #bed ,pi$mont pla91 alluvial1 #ahc ,piracy1 #afj dome/ic1 #ajd ext5t (1 9 ,appala*ians1 #agj =eign1 #ajd ( ,kaat]skill ,creek1 #aje ( ,plaat]skill ,creek1 #aje ,pirsson1 ,l\is ,v41 #dab #dea1 #egc ,pisolite1 #dfe1 #dif ,pit*/ones1 #djh1 #dec1 #dgb ,plagioclase1 #dfe ,pla91 alluvial1 #aha1 #ahd grad$1 #afi outwa%1 #cjf ,planation1 #hb ,plant k+dom1 geologic contributions (1 #feb-feh ,plant life & c>bon dioxide1 #ffe ,plant societies1 #ffg ,plants1 contributions to deposits1 #feb-feh contribution to lime/one1 #fed effect on erosion1 #aca1 #fdd ref]5ce table (1 #fec wea!r+ influ5c$ by1 #aab ,platte ,riv]1 #ahg ,plaat]skill ,creek1 piracy (1 #aje ,plugs1 volcanic1 #eia ,plumbago1 #dfe ,plung+ anticl9e1 #aee ,plutonic rocks1 #dgb ,pol> glaci]s1 #bed ,po9c>1 ,h41 #egf ,polic rocks1 #def ,polmitic rocks1 #deg ,pond+ ( /reams1 #aga ,po ,riv]1 delta (1 #bjb s$im5t c>ri$ by1 #ajg ,porphyries1 #dec ,porphyrite1 #dgb ,porphyritic rocks1 #daa ,porphyry1 #dgb ,posepny1 ,f41 #dgd ,pota%1 9 sea-wat]1 #cgg ,pot holes1 #adj ,potomac ,riv]1 #afh s$im5t c>ri$ by1 #ajg ,potoni1 ,h41 #feb ,p[ell1 ,j4 ,w41 #eai1 #eba ,precipitation1 #ej f atmosph]e1 #ea f solution1 #da1 #bbe1 #bci1 #cge-cgi ,precipitation f solution1 conditions influ5c+1 #bbe influ5c$ by alg1 #bbe ,pressures )9 e>?1 bas$ on ,laplace's law1 #efd ,pre/wi*1 ,j41 #bjc1 #bbe ,propylite1 #dgb ,protog9e1 #dgb ,protozoa1 geologic contribution (1 #ffj ,prov9cial faunas1 #ffh ,pseudomorphs1 #dfe ,psilomelane1 #dfe ,psy*ological factors #fea ,pt]idophytes1 geologic contribution (1 #feg ,pt]opod ooze1 #chj1 #chb 8,pulpit rocks10 #cej ,pumice1 #djf1 #dec1 #dgb ,pu% mora9e1 #cja ,puzzalana1 #dje ,pyrite1 #dfe ,pyrocla/ic rocks1 #djd1 #djf1 #dgb ,pyrolic rocks1 #deg ,pyrox5e1 #djj1 #dfe ,pyrox5ite1 #dag1 #deb1 #dgb ,quaquav]sal dip1 #ejd ,qu>d(elic rocks1 #def ,qu>felic rocks1 #def ,qu>tz1 #dff ,qu>tzite1 #ddg1 #dgb ,qu>tz-leucophyres1 #dec ,qu>tzophyres1 #dec ,qu>tz-porphyries1 #dec ,radiol>ian ooze1 #chj1 #chb1 #dbe1 #ffa ,ra91 am\nt (1 #ea erosion by1 #eg me*anical "w (1 #ea ,ra9-drop impressions1 #dij ,ra9fall1 effect on erosion1 #abh ,ransome1 ,f4 ,l41 #acj1 #eac ,rapids1 developm5t (1 #acc1 #adf ,rate ( erosion1 conditions affect+1 #abc ,rav9e1 #fd ,raymond1 ,r4 ,w41 #dgd ,reade1 ,t4 ,m41 #bbe1 #cff1 #efa1 #egb ,recon/ruct$ glaci]1 #bef ,r$ clay1 #chj1 #chc1 #chd ,r$ mud1 #chj ,r$ ,riv] ( ,l\isiana1 #ahh ,reid1 ,h4 ,f41 #bef1 #bei1 #bfa ,regoli?1 #djj1 #dgb ,rejuv5ation ( /reams1 #afb-afc crit]ia (1 #afd1 #afe1 #aff ,relief1 ( li?osph]e1 #aa ( ocean bas9s1 #aa repres5tation on maps1 #cj ,relief ( pressure1 a cause ( volcanic action1 #fbg ,r5du1 ,l4 ,c41 #cba1 #cbb ,re/rictive evolution1 #fgb ,rev]s$ fault1 #eag1 #eba ,rey]1 ,e41 #fcf ,rh9e ,riv]1 mat]ial 9 solution 91 #ajh ,rhizopoda1 geologic contributions (1 #ffj ,rhone ,riv]1 delta (1 #bjc mat]ial 9 solution 91 #ajh s$im5t c>ri$ by1 #ajg ,rhyolite1 #dgb ,rhyolitic /ructure1 ( lavas1 #da ,ric>d1 ,t4 ,a41 #dgd ,ri*?(51 ,b>on von1 #bc1 #fjd1 #fad1 #fae ,rigidity1 di/ribution (1 #egh ,rill-m>ks1 #cgb1 #dhi ,r9k1 ,h41 #bdh ,ripple-m>ks1 #cga1 #dhi due to w9d1 #cg ,rio ,gr&e ,riv]1 s$im5t (1 #ajg ,riv] lakes1 #aih ,riv] erosion 7see ,/ream erosion7 ,roanoke ,riv]1 #afh ,ro*es ,m\tonnes1 #cjd ,rock break+1 by *anges ( temp]ature1 #dd1 #di ,rocks1 alf]ric1 #ded alkalicalcic1 #deh alkalimirlic1 #deh alt]ations (1 #dbf aque\s1 #dfg ar5ace\s1 #dfh autocla/ic1 #ddd calcimiric1 #deh 8*imney10 #cej *loritic1 #dca classification & nom5clature1 #ddi cla/ic1 #dfh cry/all9e1 #af det]m9ation ( age1 #ae disruption by hydration1 #aaa docalcic1 #deh d(emic1 #ded d(]r\s1 #dei dohemic1 #deg dol5ic1 #def domagnesic1 #dei domalkalic1 #deh domilic1 #deg domiric1 #deh domirlic1 #deh domitic1 #deg dopolic1 #def dopotassic1 #deh dopyric1 #deg doqu>ic1 #def dosalic1 #ded dosodic1 #deh dotilic1 #deg eolian1 #dfi femic1 #ded glassy1 #djf holocry/all9e1 #dab hypog5e1 #dgj igne\s1 #af1 #cic1 #dih lead+ elem5ts (1 #cif l5d(elic1 #def l5felic1 #def magnesif]r\s1 #dei meta-igne\s1 #dga metamorphic1 #af mirlic1 #deh mitic1 #def organic1 #fdf orig9 & desc5t (1 #cic-dhe p]alkalic1 #deh p]calcic1 #deh1 #dei p]felic1 #def p]femic1 #ded p]f]r\s1 #dei p]hemic #deg p]l5ic1 #def p]magnesic1 #dei p]miric1 #deh p]m]lic1 #deh p]mitic1 #deg p]olic1 #deg p]polic1 #def p]potassic1 #deh p]qu>ic1 #def p]salic1 #ded p]sodic1 #deh p]tilic1 #deg p]pyric1 #deg phan]ocry/all9e1 #dab plutonic1 #dgb polic1 #def polmitic1 #deg porphyritic1 #daa precipitate1 #dbg 8pulpit10 #cej pyrocla/ic1 #djd1 #djf1 #dgb qu>d(elic1 #def qu>felic1 #def salfemic1 #ded salic1 #ded second>y1 #dbj s$im5t>y1 #dbb1 #dhf sodipotassic1 #deh solution (1 #dbg specific heat (1 #eeb /ratifi$1 #ad talcose1 #dca tilhemic1 #deg ,rock t]races1 #adj1 #bjd ,rock wa/e1 #ab ,roots1 w$ge-"w (1 #aab1 #aca1 #aej ,rotation ( e>?1 *ange 9 rate (1 #ege effect on /ream erosion1 #aid ,rotation & vulcanism1 #fjd ,ro?1 ,j41 #ajh ,runn+ wat] 7see ,/reams7 ,run-(f1 #ei ,russell1 ,i4 ,c41 #ajh1 #aah1 #aea1 #agb1 #aid1 #bjc1 #bcb1 #bef1 #bhc1 #chh1 #cib1 #fcf ,rutile1 #dff ,sa9t ,v9c5t1 #fje ,salfemane1 #dee ,salfemic rocks1 #ded ,sal9e lakes 7see ,salt lakes7 ,sal9e spr+s1 #bce ,salisbury1 ,r4 ,d41 #bjc1 #bef ,salt lakes1 #cia composition (1 #cgb deposits 91 #chh ,salts1 deposition (1 #cge-cgh 9 sea-wat]1 #cbd-cbf ,s&1 eolian1 #bf-cg ,s&/one1 #dbb1 #dcd1 #dgb /ratification (1 #dhg ,s&/one dikes1 #ead ,sanid9e1 #dff ,sapp+1 #abg1 #acc ,sat9sp>1 #dff ,s*i/1 #ddf1 #dgb ,s*i/osity1 #ddc ,s*midt1 ,j4 ,f4 ,j41 #ecg ,s*oh>ie ,creek1 behead$1 #aje ,scori1 #dje1 #dgc ,sc\r-&-fill1 #aid ( ,miss\ri ,riv]1 #aie ,scrope1 ,g4 ,p41 #fcf ,sea-caves1 #cej ,sea-cliffs1 #cdi ,sea1 ! 7see ,ocean7 ,sea-wat]1 ap]iodic movem5ts (1 #cch movem5ts g5]at$ by attraction1 #ccg movem5ts (1 #ccd-cdb salts 91 #cgf1 #cgg1 #cgh ,sea-waves1 caus$ by e>?quake1 #ece ,second>y rocks1 d]ivation (1 #dbj 8,second bottoms10 #bje ,secretions1 #dig ,s$im5t1 c>ri$ by ,danube1 #ajg c>ri$ by ,irrawaddy1 #ajg c>ri$ by ,mississippi1 #ajg c>ri$ by ,nile1 #ajg c>ri$ by ,po1 #ajg c>ri$ by ,potomac1 #ajg c>ri$ by ,rhone1 #ajg c>ri$ by ,rio ,gr&e1 #ajg c>ri$ by ,uruguay1 #ajg "* (1 influ5c$ by l& vegetation1 #fde deposit$ by riv]s1 #fe1 #agg-bjd deposit$ 9 lakes1 #chg deposit$ 9 sea1 #cfh-chf effect on corrasion1 #abj effect on falls1 #acg h[ c>ri$ by /reams1 #aaf ,s$im5t>y rocks1 classes (1 #dbb /ructural features (1 #dhf ,s$im5tation & vulcanism1 #fbi ,se$-plants1 #feg ,segregation ( ores1 #dge ,sei*es1 #chf ,se9e ,riv]1 intr5*$ me&]s (1 #afd ,sel5ite1 #dff ,sept>ia1 #dgc1 #die ,s]p5t9e1 #dca1 #dff1 #dgc ,s]p5t9e kames1 #cjf ,sew>d1 ,a4 ,c41 #feb ,%ale1 #dbb1 #dcd1 #dgc /ratification (1 #dhg ,%al]1 ,n4 ,s41 #bbg1 #cdi1 #ceg 7& ,davis1 ,w4 ,m471 #bef ,%all[-wat] deposits1 #cfh1 #cfi1 #cgi *>act]i/ics (1 #cgc topography (1 #cgd ,%e>+ ( glaci] ice1 #cag ,%eet erosion1 #ei ,%ell m>l1 #fee ,%ore curr5ts1 #cdb deposition by1 #cee ,%ore deposition & coa/al configuration1 #cfc ,%ore drift1 #cee ,%ore ice1 #chi ,%o%one ,falls1 #ace ,sid]ite1 #dbe1 #dff ,silicifi$ wood1 #dci ,silici\s deposits1 #dbe ,sills1 #ddf1 #eib ,sket*]ly1 ,s4 ,b41 #bc ,slate1 #dgc ,slaty /ructure1 #dda ,sli*t]1 ,c4 ,s41 #bba1 #efc1 #egf ,slumps1 #bca ,sm>agdite1 #dff ,smi?1 ,e4 ,a41 #edc ,sn[-fields1 #bdd di/ribution (1 #bdd ,sn[flakes1 =ms (1 #caj ,sn[-l9e1 #bde 9 ,&es1 #bdf 9 ,ant>ctica1 #bdf 9 ,gre5l&1 #bdf 9 ,himalayas1 #bdf ,sn[1 "w (1 #bdd ,soap/one1 #dca1 #dgc ,sodipotassic rocks1 #deh ,solms-,lauba*1 #feb ,solution1 by gr\nd-wat]1 #bbb by riv]s1 #ajh1 #abb ,solution ( rocks1 #dbg ,solv5t action1 location (1 #dhj ,sorby1 ,h4 ,c41 #cfg ,s\rce ( /reams1 #agh ,spatt] cones1 #fji1 #faj ,specific heat ( rock1 #eeb ,sp]matophytes1 geologic contribution (1 #feg ,sph5ophyllum1 #feg ,sph]icity1 a factor 9 de=mation1 #ehj ,sph]osid]ite1 #dff ,sp9el1 #dff ,spit1 !1 #ceg ,sponges1 secretions (1 #ffa ,sporadosid]ites1 #e 8,sp\t+ horn10 #cea ,spr+s1 calc>e\s1 #bce *alybeate1 #bce cold1 #bcd common1 #bce deep1 #bcd int]mitt5t1 #bce m$ic9al1 #bce m9]al1 #bce sal9e1 #bce %all[1 #bcd sulphur1 #bce ,/alactite1 #dcg1 #dgc =mation (1 #bbg ,/alagmite #dcg1 #dgc ,/4 ,an?ony ,falls1 #acf ,/apff1 ,f4 ,m4 #chh ,/aurolite1 #dff ,/eam dis*>ge f volcanoes1 #fce ,/eatite1 #dca1 #dff1 #dgc ,/ev5son1 ,d41 #cda1 #cdd1 #cgj ,/op+1 #fcb ,/oss side1 #bii ,/ra*ey1 ,r41 #ea ,/ratification1 #dhf ,/ratifi$ rocks1 #ad ,/ratigraphic geology1 #a ,/ratigraphy & fossils1 #fdg ,/ratigraphy & paleontology1 #fdg ,/ream erosion1 #ef-agg economic effects (1 #ajh influ5c$ by rock1 #abd influ5c$ by declivity1 #abc influ5c$ by /ructure1 #abe1 #abg topography develop$ by1 #ib ,/reams1 abrasion by1 #aai adju/m5t 9 ,appala*ians1 #adh adju/m5t (1 #adf1 #adg affect$ by rotation ( e>?1 #aid aggradational "w (1 #agg-bjd antec$5t1 #afi1 #aga *>act]i/ics ( aggrad+1 #agi1 #ahg comp>$ ) glaci]s1 #bfb consequ5t1 #gh corrasion by1 #aai cross-curr5ts 91 #aag decrease 9 size (1 #agi1 #ahj deposition by1 #agg dr[n+ (1 #agj effect ( *ange ( level on1 #afa1 #aga erosion by1 #eg-agg floods (1 #aji ice (1 #aah int]mitt5t1 #ga1 #gb mature1 #hf me*anical "w (1 #bbf migration f syncl9es to anticl9es1 #aei m9]al matt] 9 solution 91 #bbe old age (1 #hi ov]load+ (1 #agh1 #agi1 #ahf p]man5t1 #gj piracy (1 #ajc pond+ (1 #aga relation ( wid? to me&] belt1 #aic solution by1 #ajh1 #abb s\rces (1 #agh /ruggle = exi/5ce among1 #ajj sup]impos$1 #aej topographic adju/m5t (1 #afb1 #afc1 #aig transportation by1 #aae1 #aaf velocity (1 #aae "y1 #he ,/ream-t]races1 #bjd-bab ,/ream velocity1 effect on transportation1 #aae ,/ream "w1 #eg-bab ,/ress-accumulation1 #ehc1 #ehh ,/ri1 #bhc ,/rike1 #eja ,/rike fault1 #ebb ,/romboli1 #fcf ,/ructural adju/m5t ( valleys1 #adg ,/ructural features ( rocks1 #dhf-ebe aris+ f di/urbance1 #ejj ( igne\s rocks1 #dih ( s$im5t>y rock1 #dhf ,/ructural geology1 #a1 #dhf ,/ructural valleys1 #gg ,/ructure ( glaci] ice1 #cjh ,/ructure ( rock1 influ5ce on erosion1 #abe ,/ruggle = exi/5ce among valleys1 #ajj ,subarial erosion1 #eh ,sub-atomic =ces1 causes ( cru/al movem5t1 #eef ,subdivisions ( geology1 #a ,subglacial load1 #bhb ,subsid5ce1 effect on coa/-l9es1 #cca ,suess1 ,edw41 #ech ,sulphur1 #dff ,sulphur spr+s1 #bce ,sun-cracks1 #cgc1 #dij ,sup]glacial load1 #bhb ,sup]impos$ /reams1 #aej ,surface mora9es1 #bff ,susquehanna ,riv]1 #afh ,switz]l&1 sn[-fields (1 #bde ,sy5ites1 #dae1 #deb1 #dgc ,syncl9e1 #aeg1 #ejd ,syncl9oria1 #ejd ,syssid]ites1 #e ,ta*ylite1 #dgc ,tait1 ,p4 ,g41 #eeb1 #egb1 #egc 7& ,?ompson1 ,j471 #efj1 #egi ,talc1 #dff ,talcose rock1 #dca ,talus1 #aab ,talus cone1 #ahb ,talus glaci]1 #bcc1 #bcb ,t>r1 ,r4 ,s41 #afe ,temp]ature1 at c5tre ( e>?1 #ega atmosph]ic1 #dc1 #df1 #di bas$ on ,laplace's law1 #efd effect on erosion1 #abi effects ( *anges on rocks1 #dd expansion & contraction due to *anges (1 #dd 9 excavations1 #efi ( int]ior ( e>?1 #eei-egj ( lavas1 #fae1 #fbg ,t5nessee ,riv]1 hi/ory (1 #afh-afi ,t5sion jo9ts1 #ead ,t]m9al mora9e1 #bff1 #cja ,t]races1 /ream1 #bjd-bab flood-pla91 #bje rock1 #adj1 #bjd t]m9i (1 #baj wave-built1 #cfc wave-cut1 #cea1 #cec ,t]rig5\s deposits1 9 sea1 #cgi ,?allophytes1 geologic contribution (1 #fec ,?ames ,riv]1 #bbd mat]ial 9 solution 91 #ajh ,?ibetan plateau1 #edh ,?ompson1 ,james1 #cbb1 #efj1 #egi ,?ompson1 ,w4 ,g41 #aai 8,?or(>es10 #ceh ,?ru/-fault1 #eag1 #eah ,tides1 #d1 #cch effect on rotation1 #d ,tild51 ,w4 ,a41 #fbj ,tilhemic rocks1 #deg ,till1 #dgc ,titanite1 #dfg ,todd1 ,j4 ,e41 #aie ,topaz1 #dfg ,topographic adju/m5t ( /reams1 #afb1 #afc1 #aig ,topographic effects ( glacial erosion1 #bhg ,topographic effects ( gr\nd-wat]1 #bca ,topographic map1 explanation (1 #cj ,topographic maturity1 #hf ,topographic old age1 #hi ,topographic y\?1 #hf ,topography1 develop$ by riv] erosion1 #ib dune1 #cb l&slide1 #bca mature1 #hf ( alluvial deposits1 #aif ( glaci]s1 #bff ( ocean bottom1 #cbf ( %all[-wat] deposits1 #cgd y\?ful #hf ,top-set b$s1 #bjb ,tra*yte1 #dgc ,transportation1 #aaj by glaci]s1 #bha by ocean curr5ts1 #cfg by /reams1 #aae1 #aai by waves1 #ced by w9d1 #bb1 #be ,trap1 #dai1 #dgc ,trav]t9e1 #dgc ,trees1 uproot+ (1 #dj ,tremolite1 #ddg1 #dfg ,tribut>ies1 developm5t (1 #gh position (1 #gi topographic adju/m5t (1 #aig ,tripoli1 #ffa ,tripolite1 #dbf ,tr\t creek1 #aic ,ts*]mak1 ,g41 #ech ,tufa 7see ,tuffs7 ,tufa cones1 #faa ,tufa deposits1 #faa ,tuffs1 #djd1 #dcd1 #dgc ,tusc>ora deep1 #edh ,two ,m$ic9e ,riv]1 #aed1 #aeg ,tyndall1 ,j41 & ,huxley1 ,t4 ,h41 #cbb ,udd51 ,j4 ,a41 #bb ,u9ta ,m\nta9s1 lat]al mora9es (1 #cjc ,und]gr\nd wat] 7see ,gr\nd-wat]7 ,und]t[1 #cda deposition by1 #cee erosion by1 #cdb1 #cdg ,unit$ ,/ates ,geological ,survey1 ,,vi41 #cb ,upham1 ,w41 #chh ,uproot+ ( trees1 #dj ,uralite1 #dca ,uruguay ,riv]1 s$im5t c>ri$ by1 #ajg ,usiglio1 #cge ,valleys1 affect$ by folds1 #aed antec$5t 7see ,/reams1 antec$5t7 canoe-%ap$1 #aee consequ5t1 #gh c\rses (1 #gg developm5t (1 #fc1 #gj1 #gc1 #hj hang+1 #afd1 #bij limits ( gr[?1 #fg olde/ p>ts1 #gf pr(iles (1 #ff relations to lakes1 #gd slopes (1 #id special =ms (1 #id /ructural1 #gg /ruggle = exi/5ce among1 #ajj ,van ,hise1 ,c4 ,r41 #bai1 #dcd1 #ddh1 #dgd1 #dgi1 #ejd1 #edc1 #eee1 #egj ,vegetation1 effect on dunes1 #bi effect on erosion1 #aca1 #fdd effect on s$im5ts1 #fde effect on wea!r+1 #aca ,ve9s1 #bbc1 #dbh1 #eaa ,v]mes1 geologic contribution (1 #ffb ,v]meule1 ,c4 ,c41 #aji ,v]tebrata1 geologic contribution (1 #ffc ,vesuvius1 #fje ,virg9ia1 natural bridge (1 #aef ,viridite1 #dfg ,volcanic action1 causes (1 #fbc-fcc activity1 p]iodicity (1 #fjg a%1 #bc1 #djd1 #eib1 #fag bombs1 #djf1 #eib1 #fag c9d]s1 #eib cones1 #ejj dbris 9 sea1 #cha du/ 7see ,volcanic a%7 eruptions1 #eid & atmosph]ic pressure1 #fjf & tidal /ra91 #fjg types (1 #eic gases1 #fag-fbc action (1 #fag k9ds (1 #fah proportions (1 #fbj1 #fbb s\rces (1 #fai1 #fbj1 #fba1 #fcc glass 7see ,obsidian7 9 sea1 #cha mud1 #chj fl[s (1 #faj neck1 #ejj plug1 #ejj rocks1 #cie-dah residual gases 91 #fai smoke1 #eib1 #fag ,volcanoes1 #eii-faa co9cid5ce 9 eruption (1 #fjf cones (1 #fjh di/ribution (1 9 curv$ l9es1 #fjc di/ribution (1 9 latitude1 #fjc di/ribution (1 9 relation to cru/al movem5ts1 #fja1 #fjd1 #fbh di/ribution (1 9 relation to l& & sea1 #eii di/ribution (1 9 "t1 #eii indep5d5ce (1 #fje1 #fbc p]iodicity (1 #fjg relations (1 #fjd-fjg relations to "o ano!r1 #fje ,volume ( ocean1 #cbe ,vuggs1 #dcg ,vulcanism1 #b1 #eij-fcg causes (1 #fbc-fcc effects on coa/-l9es1 #ccb 9 ocean1 #ccb ,vulcanism & deep s$im5tation1 #fbi gr\nd-wat]1 #fce rotation1 #fjc ,wacke1 #dbb1 #dgc1 #fde ,wad1 #dfg ,walcott1 ,c4 ,d41 #aid1 #bdf1 #cga1 #dch1 #ddj1 #dda1 #ejb1 #ejc1 #eji ,wallace1 ,a4 ,r41 #ffe1 #ffh ,wal!r1 ,j41 #ej1 #fgj ,w>m+1 ,e41 #ffg ,w>p+1 effect (1 on /reams1 #aga ( e>?'s cru/1 #ebf1 #eda1 #edb ,wasat* ,m\nta9s1 lat]al mora9es (1 #cjc ,wa%+ton1 ,h4 ,s41 #dab1 #dea1 #egc ,wa/e ( glaci]s1 #bgc ,wat] 7see ,/reams1 ,gr\nd-wat]1 ,ocean1 etc47 am\nt (1 #g geologic activity (1 #h ,wat]-gaps1 #ada1 #afg ,wat]falls1 #acb developm5t (1 #acc ,m9nehaha1 #acg ,niag>a1 #aci ,%o%one1 #ace ,/4 ,an?ony1 #ace ,upp] ,yosemite1 #ach ,yell[/one1 #ace ,wat]falls & s$im5t1 #acg ,wat]-lime1 #dgc ,wat]-table1 #ga1 #bae ,wat]-vapor1 climatic effects (1 #fdc ,wave-built t]races1 #cfc ,wave-cut t]races1 #cea1 #ceb ,wave erosion1 #cdb-ced range (1 #cdf topographic features develop$ by1 #cdi ,wave erosion & horizontal configuration1 #cec1 #cfc1 #cfd ,wave-m>ks1 #dij ,wave-motion1 #cci ,waves1 #cci deposition by1 #cee erosion by1 #cdb-ced =ce (1 #cdd transportation by1 #ced "w (1 #cdb-cff ,wea!r+1 #ed1 #aaj1 #bbf affect$ by life1 #fdd aid$ by plants1 #aab aid$ by hot vapors1 #aac effect ( gravity1 #aab effect ( jo9ts1 #aea1 #aec importance (1 9 valley gr[?1 #aad ,w$gework ( ice1 #de1 #dh1 #aej ( roots1 #aab1 #aca1 #aej ,we$1 ,w4 ,h41 #bbe1 #bcg1 #dgd1 #fef ,wells1 artesian1 #bdb fl[+1 #bcd1 #bdb1 #bdc ,:eel+ well1 temp]ature (1 #efi ,:ite glaci]1 #bfc ,:itfield1 ,j4 ,e4 7& ,goo*1 ,f4 ,a471 #bcf ,williams1 ,h4 ,s41 #feh ,willis1 ,b41 #aeg1 #afh1 #afi1 #beg1 #cdd1 #cee1 #cfe1 #eaf1 #edc1 #eej ,w9*ell1 ,h4 ,v41 #dgd ,w9d1 abrasion by1 #ch effects on plants1 #dj movem5ts ( sea1 g5]at$ by1 #ccf transports organisms1 #da "w (1 #ba-da ,w9d-bl[n du/1 #bb ,w9d-bl[n s&s1 #be ,w9d-ripples1 #cg ,w9sl[1 ,a41 #dgd ,wiscons9 ,riv]1 dells (1 #aeb ,woodw>d1 ,r4 ,s41 #efj1 #eha ,"w ( glaci]s1 #bha ,wy&otte ,cave1 #bbg1 #bbh ,yazoo ,riv]1 #ahh ,yell[/one ,p>k1 geys]s (1 #bch hot spr+s (1 #bbe ,yell[/one ,riv]1 canyon (1 #ajj falls (1 #ace ,yukon ,riv]1 delta (1 #bjb ,zeill]1 #feb ,zeolites1 #dbh1 #dfg ,zircon1 #dfg ,zittel1 ,k4 von1 #feh1 #fei ,zone ( fracture1 #bai1 #dbg ,,footnotes3 #a ,! ,e>?4 ,johnson's ,encyclopdia4 ,see also /atem5t ( ,murray 9 ,smi?sonian ,an4 ,rept41 #ahii1 p4 #cab4 ,repr9t f ,brit4 ,a4 ,a4 ,s41 ,dov] meet+1 #ahii1 & ,scot4 ,geog4 ,mag41 ,vol4 ,,xv1 #ahii1 p4 #eaa4 #b ,its specific gravity z a :ole is ab\t #e4eg1 & ! specific gravity ( its out] portion is ab\t #b4g4 #c ,= an excell5t /udy ( ! erosion1 transportation1 & s$im5tation p]=m$ by ! atmosph]e1 see ,udd51 ,j\r4 ( ,geol41 ,vol4 ,,ii1 pp4 #cah-cca4 ,see also ,pop4 ,sci4 ,mo41 ,septemb]1 #ahif4 #d ,! ,eruption ( ,krakatoa4 ,committee ( ! ,royal ,society1 #ahhh4 #e ,a brief acc\nt ( ! influ5ce ( ! du/ on sunsets is f\nd 9 ,davis's ,elem5t>y ,meteorology1 pp4 #he & #aai4 #f ,sci5ce1 ,new ,s]41 ,vol4 ,,iv1 p4 #haf1 #ahif4 #g ,von ,ri*t(54 8,*9a40 #h ,sket*]ley & ,k+smill4 ,qu>4 ,j\r4 ,geol4 ,soc41 ,vol4 ,,li1 #ahie1 pp4 #bch-bed4 #i ,*amb]l94 ,j\r4 ( ,geol41 ,vol4 ,v1 p4 #gie4 #aj ,a ?or\ghgo+ /udy ( ! ,=mation ( ,s& ,dunes 7by ,v4 ,corni%7 is to be f\nd 9 ! ,geog4 ,j\r41 ,vol4 ,,ix1 #ahig1 pp4 #bgh-cji4 #aa ,blan=d4 ,geology ( ,india1 #b;d ed41 p4 #dee et seq4 #ab ,corni%1 loc4 cit4 #ac ,corni%1 loc4 cit41 p4 #bid4 #ad ,dill] /ates 7#ag? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 p4 #dej7 t on ! coa/ ( ,oregon ! slope ( dunes is sometimes #dj4 #ae ,f folio preface1 ,u4 ,s4 ,geol4 ,surv4 #af ,cr$n]4 ,elem5te d] ,geologie1 #f? ed41 p4 #bga4 #ag ,m]rill4 ,rocks1 ,rock ,wea!r+1 & ,soils1 p4 #bie4 #ah ,c[les4 ,! ,ecological ,relations ( ! ,vegetation ( ! ,s& ,dunes ( ,lake ,mi*igan4 ,botanical ,gazette1 ,vol4 ,,xxvii1 #ahii4 ,an excell5t /udy ( ! relations ( s& dunes & vegetation4 #ai ,= example1 9 ! ,big ,horn ,m\nta9s ( ,wyom+4 #bj ,x %\ld be not$ t x is ! *ange ( temp]ature ( ! rock surface1 n ! *ange ( temp]ature ( ! air above x1 :i* is to be consid]$4 ,_m data conc]n+ temp]ature *anges are to be f\nd 9 ,b>?olomew's ,atlas ( ,meteorology4 #ba ,buckley4 ,wiscons9 ,survey1 ,bull4 ,,iv1 #ahii1 pp4 #ha-c4 #bb ,liv+/one has report$ t ! temp]ature ( rock surfaces 9 ,africa sometimes rea*es #acg ,fahr4 dur+ ! day1 & cools suffici5tly at night to split (f blocks ( #bjj lbs4 weight4 #bc ,buckley4 ,surv4 ( ,wis41 ,bull4 ,,iv1 pp4 #ai1 #bj4 #bd ,= an excell5t discussion ( erosion 9 dry regions see ,wal!r's ,die ,d5udation 9 d] ,w/e4 #be ,on ! assumption t cond5sation takes place at an av]age elevation ( #cjjj feet1 x has be5 e/imat$ t ! =ce necess>y to evaporate & diffuse ! moi/ure :i* falls z ra9 & sn[ w\ld be equival5t to #cjj1jjj1jjj1jjj horse-p[] con/antly 9 op]ation4 7,/ra*ey1 ,lectures on ,geography1 p4 #ade47 #bf ,mc,gee4 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,,viii1 pp4 #hg-aab4 #bg ,= a discussion ( convex & concave erosion slopes see ,ba91 ,geol4 ,surv4 ( ,ia41 ,vol4 ,,vi1 p4 #ddi4 #bh ,great riv]s1 l ! ,mississippi1 cut _! *annels some:at bel[ sea-level1 b probably n by an am\nt exce$+ ! dep? ( ! /ream itself 7see p4 #gi74 #bi ,davis4 ,j\r4 ( ,geol41 ,vol4 ,x1 p4 #hg4 #cj ,ibid41 p4 #gg et seq4 #ca ,9 regions :]e canyons are common1 ! t]m is (t5 appli$ to all valleys4 #cb ,humphreys & ,abbot4 ,physics & ,hydraulics ( ! ,mississippi ,riv]4 #cc ,f ,russell's ,riv]s ( ,nor? ,am]ica1 p4 #gh4 #cd ,alkal9e c>bonates consid]$ z sodium c>bonates4 #ce ,c>bonic acid by diff]5ce4 #cf ,babb4 ,sci5ce1 ,vol4 ,,xxi1 p4 #cdc4 #ahic4 #cg ,quot$ by ,mason4 ,wat]-supply1 p4 #bjd4 #ch ,sot4 ,geog4 ,mag41 ,vol4 ,,iii1 p4 #gf4 #ahhg4 #ci ,acids & bases comb9$ accord+ to ! pr9ciples indicat$ by ,buns54 #dj ,*emical ,geology1 ,vol4 ,i1 pp4 #gf1 #gg1 ,engli% ed41 #ahed4 #da ,allgeme9e und *emis*e ,geologie1 ,vol4 ,i1 pp4 #def1 #deg4 #ahgi4 #db ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #gi4 #dc ,= disa/r\s floods ( ! l[] ,mississippi1 see ,johnson1 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,,ii1 pp4 #bj-be4 ,= effect ( precipitation & =e/s on floods1 see ,russell's ,meteorology1 pp4 #aih-bag1 & ,v]meule1 ,report on ,wat] ,supply1 ,geol4 ,surv4 ( ,n4 ,j4 #dd ,an excell5t discussion ( ?is subject is giv5 by ,gilb]t 9 ,! ,h5ry ,m\nta9s1 pp4 #ii et seq41 & m briefly 9 ! ,am4 ,j\r4 ,sci41 ,vol4 ,,xii1 p4 #he et seq4 #ahgf4 #de ,j\r4 ( ,geol41 ,vol4 ,,iv1 p4 #gah4 ,an excell5t summ>y ( ! pr9ciples ( ,rock ,wea!r+4 #df ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #ag4 #dg ,w4 ,g4 ,?ompson4 ,nature1 ,vol4 ,i1 p4 #eee1 #ahgj4 ,! ,matap$iac ,riv]1 ,n4 ,b4 ,cit$ by ,russell 9 ,riv]s ( ,nor? ,am]ica1 p4 #be4 #dh ,dutton4 ,t]ti>y ,hi/ory ( ! ,gr& ,canyon ,di/rict1 ,mono4 ,,ii1 ,u4 ,s4 ,geological ,survey4 #di ,! t]ms rapids1 falls1 & cat>acts are r loosely us$4 ,_m mod]ate rapids are incorrectly call$ falls4 ,! 8,falls ( ! ,ohio0 is an example4 ,! t]m cat>act is (t5 appli$ to v /eep rapids or falls4 #ej ,gilb]t1 article on ,niag>a ,falls1 9 ,physiography ( ! ,unit$ ,/ates4 #ea ,gilb]t4 ,am4 ,j\r4 ,sci41 ,vol4 ,,xii4 p4 #ii1 #ahgf4 #eb ,= a brief acc\nt ( ?is fall see ,gilb]t 9 ,physiography ( ! ,unit$ ,/ates4 #ec ,gilb]t4 ,sci5ce1 ,vol4 ,,viii1 p4 #bje1 #ahhf4 #ed ,see ,campbell1 ,j\r4 ,geol41 ,vol4 ,,iv1 pp4 #efg1 #feg4 #ee ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #bhj4 ,! influ5ce ( jo9ts on dra9age is fur!r discuss$ by ,hobbs1 ,j\r4 ,geol41 ,vol4 ,,ix1 p4 #dfi4 #ef ,see ,willis4 ,! ,nor!rn ,appala*ians1 9 ,physiography ( ! ,unit$ ,/ates4 #eg ,?is process ( adju/m5t has be5 well describ$ by ,davis 9 ,! ,riv]s & ,valleys ( ,p5nsylvania1 ,natl4 ,geog4 ,mag41 ,vol4 ,i1 p4 #baa et seq4 #eh ,?is sort ( adju/m5t may be call$ topographic adju/m5t4 ,a tribut>y is 9 topographic adju/m5t :5 its gradi5t is h>moni\s ) t ( its ma94 #ei ,davis4 ,! ,se9e1 ! ,meuse & ! ,moselle4 ,nat'l ,geog4 ,mag41 ,vol4 ,,vii1 pp4 #aha-bjb1 & #bbh-bch4 ,an article :i* ?r[s mu* light on ! behavior ( riv]s4 #fj ,ano!r view has be5 advocat$ by ,t>r1 ,am4 ,geol4 ,vol4 ,,xxi1 pp4 #cea-cgj4 #fa ,campbell4 ,bull4 ,geol4 ,soc4 ( ,am41 ,vol4 ,,xiv1 p4 #bgg4 #fb ,willis4 ,physiography ( ! ,unit$ ,/ates4 ,! ,nor!rn ,appala*ians4 #fc ,= excell5t acc\nts ( ! riv]s ( ! ,appala*ian ,m\nta9s see ,davis1 ,riv]s ( ,nor!rn ,new ,j]sey1 ,nat'l ,geog4 ,mag41 ,vol4 ,,ii1 pp4 #ha-aaj2 & ,riv]s ( ,p5nsylvania1 op4 cit41 pp4 #ahc-bec2 ,willis1 ,! ,nor!rn ,appala*ians1 ,physiography ( ! ,unit$ ,/ates1 pp4 #afi-bjb2 ,hayes1 ! ,s\!rn ,appala*ians1 op4 cit41 pp4 #cje-ccf2 ,hayes & ,campbell1 ,! ,geomorphology ( ! ,s\!rn ,appala*ians1 ,nat'l ,geog4 ,mag41 ,vol4 ,,vi1 pp4 #fc-abf1 & ,hayes1 ,physiography ( ! ,*attanooga ,di/rict1 #ai? ,ann4 ,rep4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii1 pp4 #a-eh4 #fd ,?is is ! case at ,davis & ,lone ,/>4 ,capt ,h[ell1 ,miss4 ,riv4 ,commission4 #fe ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #bgi4 #ff ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #bgi4 #fg ,hayes4 ,physiography ( ! ,*attanooga ,di/rict1 #ai? ,ann4 ,rep41 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii1 pp4 #i-eh4 ,see1 also1 ,hayes & ,campbell1 ,geomorphology ( ! ,s\!rn ,appala*ians1 ,nat'l ,geog4 ,mag41 ,vol4 ,,vi1 pp4 #fc-abf4 #fh ,figs4 #afe-afh are bas$ on reports ( ,hayes1 & ,hayes & ,campbell1 already ref]r$ to4 ,drawn by ,e4 ,s4 ,ba/94 #fi ,a "q might be rais$ 9 ?is case z to :at %\ld be call$ ! s\rce4 ,a spr+ issues f b5ea? ! surface & fl[s away 9 a /ream4 ,! /ream is said to beg9 :]e ! wat] appe>s at ! surface1 ?\gh 9 "s cases ! wat] ( ! spr+ 0 a subsurface /ream be=e x rea*$ ! surface4 ,wat] escap+ f b5ea? a glaci] z a /ream may likewise be consid]$ a spr+ at ! po9t ( its issue4 #gj ,davis4 ,sci5ce1 ,vol4 ,x1 p4 #adb1 #ahhg4 #ga ,l4 ,c4 ,johnson4 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,,ii1 pp4 #bj-be1 #ahia4 #gb ,jeff]son4 ,nat'l ,geog4 ,mag41 ,vol4 ,,xiii1 pp4 #cgc-hd4 #gc ,accord+ to map publi%$ by ! ,mississippi ,riv] ,commission 9 #ahhg4 #gd ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #aad4 #ge ,gilb]t4 ,am4 ,j\r4 ,sci41 ,vol4 ,,xxvii1 #ahhd1 pp4 #dbg-cd4 #gf ,cooley4 ,rept4 ,u4 ,s4 ,eng9e]s = #ahgi-hj1 ,pt4 ,,ii1 pp4 #ajfj & #ajga4 #gg ,g]b]4 ,cit$ by ,todd4 ,bull4 #aeh1 ,u4 ,s4 ,geol4 ,surv41 pp4 #aej1 #aea4 #gh ,*amb]l94 ,j\r4 ( ,geol41 ,vol4 ,x1 pp4 #gdg-ged4 #gi ,= an excell5t discussion ( deltas1 see ,gilb]t1 ,fif? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 pp #ajd-h4 ,also ,lake ,bonneville1 ,monograph ,i1 ,u4 ,s4 ,geol4 ,surv4 7same article74 #hj ,davis4 ,physical ,geography1 p4 #bid4 #ha ,humphreys & ,abbot4 ,physics & ,hydraulics ( ! ,mississippi ,riv]4 #hb ,cor!ll4 ,nat'l ,geog4 ,mag41 ,vol4 ,,viii1 p4 #cea1 #ahig4 #hc ,russell4 ,riv]s ( ,nor? ,am]ica1 p4 #acb4 #hd ,pre/wi*4 ,*emical & ,physical ,geology1 ,vol4 ,i1 p4 #he4 #he ,geike4 ,text-book ( ,geology1 #c;d ed41 p4 #djb4 #hf ,m$licott & ,blan=d1 ,geology ( ,india4 ,*ap4 ,,xvii2 ,m$licott1 ,records ( ! ,geological ,survey ( ,india1 #ahha2 ,oldham1 ,geology ( ,india1 #b;d ed41 ,*ap4 ,,xvii2 & ,f]guson1 ,q4 ,j4 ,g4 ,s41 ,vol4 ,,xix1 pp4 #cba-ed4 ,! ext5t ( ?is & o!r deltas is v>i\sly /at$1 probably because x is difficult to det]m9e ! exact position ( its head & bord]s4 #hg ,dana4 ,manual ( ,geology1 #d? ed41 p4 #aih4 #hh ,salisbury & ,kmmel4 ,lake ,passaic4 ,ann4 ,rept4 ( ! ,/ate ,geologi/ ( ,new ,j]sey1 #ahic1 & ,j\r4 ( ,geol41 ,vol4 ,,iii4 p4 #ecc4 #hi ,gilb]t4 ,lake ,bonneville1 ,mono4 ,i1 ,u4 ,s4 ,geol4 ,surv4 #ij ,= discussions ( t]races see ,gilb]t's ,h5ry ,m\nta9s1 p4 #abf2 ,davis' ,riv] ,t]races 9 ,new ,engl&1 ,bull4 ( ! ,mus4 ( ,comp4 ,zool41 ,geol4 ,s]ies1 ,vol4 ,v1 pp4 #bhb-cdf2 & ,dodge1 ,proc4 ,bo/on ,soc4 ( ,nat4 ,hi/41 ,vol4 ,,xxvi1 pp4 #beg-gc4 #ia ,davis1 ,bull4 ,mus4 ,comp4 ,zool41 ,geol4 ,s]41 ,vol4 ,v4 #ib ,?is po9t has rec5tly be5 emphasiz$ by ,davis1 loc4 cit41 pp4 #bhb-cdf4 #ic ,murray4 ,scot4 ,geog4 ,mag41 ,vol4 ,,iii1 p4 #gj1 #ahhg4 #id ,hosk9s4 #af? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 p4 #hec4 #ie ,van ,hise4 ,pr9ciples ( ,nor? ,am]ican ,pre-,cambrian ,geology1 #af? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv4 #if ,= a full discussion ( ?is subject see ,k+1 #ai? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii1 & ,sli*t]1 ,wat] ,supply & ,irrigation1 ,pap] ,no4 #fg1 ,u4 ,s4 ,geol4 ,surv4 #ig ,= tables see ,buckley1 ,build+ & ,ornam5tal ,/ones1 ,bull4 ,,iv1 ,wis4 ,surv41 & ,m]rill1 ,/ones = ,build+ & ,decoration1 & v>i\s ,survey ,reports4 #ih ,x is probable t ! porosity decreases 9 m ?an an ari?metic ratio1 bo? because ! deep] rocks are n ( por\s k9ds1 & because ( ! pressure :i* t5ds to close op5+s4 #ii ,sli*t] 7op4 cit41 p4 #ae7 e/imates t ! gr\nd-wat] is suffici5t 9 am\nt to cov] ! e>?'s surface to a dep? ( #cjjj to #cejj feet4 ,e>li] e/imates gave /ill high] figures 7see ,delesse1 ,bull4 ,soc4 ,geol41 ,france1 ,second ,s]ies1 ,vol4 ,,xix1 #ahfa-fb1 p4 #fd74 #ajj ,geikie4 ,text-book ( ,geology1 #c;d ed41 p4 #cfg4 #aja ,ibid41 p4 #cgh4 #ajb ,pre/wi*1 ,q4 ,j4 ,geol4 ,soc41 ,vol4 ,,xxviii1 p4 lxvii4 #ajc ,reade4 ,liv]pool ,geol4 ,soc41 #ahgf & #ahhd4 #ajd ,?is is n true 9 ! case ( m9]als1 su* z lime c>bonate1 dissolv$ "u ! influ5ce ( gases 9 solution 9 ! wat]4 #aje ,we$4 ,! ,=mation ( ,hot ,spr+s ,deposits4 ,excursion to ! ,rocky ,m\nta9s4 ,compte ,r5du4 ,fif? ,session ( ! ,int]national ,geological ,congress1 p4 #cfj1 & ,n9? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 pp4 #fac-gf4 ,also ,b4 ,m4 ,davis1 ,sci5ce1 ,vol4 ,,vi1 pp4 #ade-eg1 #ahig4 #ajf ,= a racy & int]e/+ acc\nt ( cav]ns see ,%al]'s ,aspects ( ! ,e>?4 #ajg ,russell has emphasiz$ ?is po9t 9 #bj? ,ann4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii1 pp4 #aic-bjb1 & ,cross1 #ba/ ,ann4 ,u4 ,s4 ,geol4 ,surv41 ,"p ,,ii1 pp4 #abi-aej4 #ajh ,goo* & ,:itfield4 ,bull4 #dg1 ,u4 ,s4 ,geol4 ,surv4 #aji ,copi$ f ,russell1 ,mono41 ,,xi4 ,u4 ,s4 ,geol4 ,surv41 p4 #agf4 #aaj ,correction = specific gravity only approximate1 z specific gravity 0 n giv5 9 orig9al analyses4 #aaa ,z c>bonates4 #aab ,z c>bonate4 #aac ,z oxide4 #aad ,z c>bonate4 #aae ,z sodium *loride4 #aaf ,z fluoride ( calcium4 #aag ,oxyg5 add$ to ,si,o to =m ,si,o ( ,na,si,o4 #aah ,lit]s ( gas ?r[n (f p] lit] ( wat]4 #aai ,we$4 ,n9? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 pp4 #fac-gf1 & ,am4 ,j\r4 ,sci41 ,vol4 ,,xxxvii1 #ahhi1 pp4 #cea-ei4 #abj ,geikie4 ,geological ,sket*es1 pp4 #bjf-ch4 ,hayd54 ,am]4 ,j\r4 ,sci41 ,vol4 ,,iii1 #ahgb1 pp4 #aje-ae & #afa-gf4 #aba ,*amb]l94 ,geol4 ( ,wis41 ,vol4 ,i1 pp4 #fhi-ig1 & ,fif? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 pp4 #aca-gc4 ,! =m] a brief1 & ! latt] an elaborate1 exposition ( ! pr9ciples involv$4 #abb ,russell4 ,nat'l ,geog4 ,mag41 ,vol4 ,,iii1 pp4 #abg & #aha4 #abc ,= an acc\nt ( exp]im5ts illu/rat+ ! mobility ( ice see ,aitk91 ,am4 ,j\r4 ,sci41 ,vols4 ,v1 p4 #cjc1 & ,,xxxiv1 p4 #adi1 & ,nature1 ,vol4 ,,xxxix1 p4 #bjc4 #abd ,j\r4 ( ,geol41 ,vol4 ,,iii1 p4 #hhh4 #abe ,! foll[+ li/ includes _m ( ! m available articles & treatises on exi/+ glaci]s2 o!rs are ref]r$ to 9 ! foll[+ pages4 ,alaskan glaci]s3 ,reid1 7#a7 ,nat4 ,geog4 ,mag41 ,vol4 ,,iv1 pp4 #ai-ee2 7#b7 ,sixte5? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,"p ,i1 pp4 #dba-dfa4 ,russell1 7#a7 ,nat4 ,geog4 ,mag41 ,vol4 ,,iii1 pp4 #agf-ahh2 7#b7 ,j\r4 ( ,geol41 ,vol4 ,i1 pp4 #bai-bde4 ,glaci]s 9 ! ,unit$ ,/ates3 ,russell1 7#a7 ,fif? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 pp4 #cji-cee2 7#b7 ,eighte5? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,"p ,,ii1 pp4 #cgi-dji2 7#c7 ,glaci]s ( ,nor? ,am]ica4 ,gre5l& glaci]s3 ,*amb]l91 ,j\r4 ( ,geol41 ,vol4 ,,ii1 pp4 #gfh-ghh2 ,vol4 ,,iii1 pp4 #fa-fi1 #aih-bah1 #dfi-dhj1 #efe-ehb1 #ffh-fha1 & #hcc-hdc2 ,vol4 ,,iv1 pp4 #ehb-eib4 ,salisbury1 ,j\r4 ( ,geol41 ,vol4 ,,iii1 pp4 #hge-ijb1 & ,vol4 ,,iv1 pp4 #gfi-haj4 ,glaci]s 9 g5]al3 ,%al] & ,davis1 ,illu/rations ( ! ,e>?'s ,surface2 ,=bes1 ,norway & its ,glaci]s1 & ,!ory ( ,glaci]s2 ,heim1 ,h&bu* d] ,glets*]kunde4 #abf ,reid4 ,natl4 ,geog4 ,mag41 ,vol4 ,,iv1 p4 #dd4 #abg ,r9k's ,gre5l&4 #abh ,reid4 ,v>iations ( ,glaci]s4 ,j\r4 ( ,geol41 ,vols4 ,,iii1 p4 #bgh2 ,v1 p4 #cgh2 ,,vi1 p4 #dgc2 ,,vii1 p4 #bag2 ,,viii1 p4 #aed2 ,,ix1 p4 #bej1 & ,x1 p4 #cac4 #abi ,= example1 9 ! ,middle ,blase ,dale glaci]1 ,isl& ( ,disco1 ,j\r4 ( ,geol41 ,vol4 ,,ii1 p4 #ghd1 & 9 ! ,b[do9 glaci] 7,fig4 #bdb74 #acj ,c5timet]-gramme-second sy/em4 ,! rate ( conductivity has n be5 v accurately det]m9$4 #aca ,russell4 ,j\r4 ( ,geol41 ,vol4 ,,iii1 p4 #hbc4 #acb ,geikie4 ,! ,great ,ice ,age1 #c;d ed41 p4 #ebi4 #acc ,c>ri$ out by ,c4 ,e4 ,peet & ,e4 ,c4 ,p]i%o "u ! direction ( "o ( ! au?ors4 #acd ,ueb] die ,pla/icitt d] ,eiskry/alle4 ,neues ,jahrbu* fr ,m9]alogie1 etc41 #ahie1 ,bd4 ,,ii1 p4 #baa4 #ace ,on ! ,pla/icity ( ,glaci]s & o!r ,ice4 ,proc4 ,roy4 ,soc41 ,vol4 ,,xliv1 #ahhh1 pp4 #cca-fg 7) ,d4 ,a4 ,kidd72 ,vol4 ,,xlviii1 #ahij1 pp4 #bei1 #bfj2 ,vol4 ,,xlix1 #ahia1 pp4 #cbc-dc4 #acf ,grnl&-,exp$ition d] ,gesells*aft fr ,erdkunde zu ,b]l91 #ahia-ic1 ,bd4 ,i1 p4 #dia et seq4 #acg ,ref]5ces on glaci] /ructure & motion4--,l4 ,agassiz1 tudes sur les ,glaci]s1 ,neu*tel1 #ahdj4 ,r5du1 ,?orie des ,glaci]s de la ,savoie1 ,soc4 ,roy4 ,acad41 ,savoie1 ,mm4 #ahdj 79 ,engli%1 ed4 by ,geo4 ,=bes1 ,london1 #ahgd74 ,j4 de ,*>p5ti]1 ,essai sur les ,glaci]s et le t]ra9 erratique du ,bas9 du ,rhone1 ,lausanne1 #ahda4 ,f4 ,j4 ,hugi1 ,ueb] das ,wes5 d] ,glets*] und ,w9t]eise 9 dem ,eisme]1 ,/uttg>t1 #ahdb4 ,r4 ,mallet1 ,! ,me*anism ( ,glaci]s1 ,j\r4 ,geol4 ,soc4 ,dubl91 ,vol4 ,i1 p4 #cag2 ,on ! ,pla/icity ( ,glaci] ,ice1 ,j\r4 ,geol4 ,soc4 ,dubl91 #ahde1 ,vol4 ,,iii1 p4 #abb2 ,on ! ,brittl5ess & ,non-pla/icity ( ,glaci] ,ice1 ,phil4 ,mag41 ,,xxvi1 p4 #ehf4 ,james ,?ompson1 ,on ! ,pla/icity ( ,ice z ,manife/$ 9 ,glaci]s1 ,roy4 ,soc4 ,proc41 ,vol4 #h1 #aheg1 pp4 #dee-eh4 ,j4 ,tyndall & ,t4 ,h4 ,huxley1 ,on ! ,/ructure & ,motion ( ,glaci]s1 ,phil4 ,trans41 #aheg1 ,vol4 ,,cxlvii1 p4 #cbg4 ,j4 ,d4 ,=bes1 ,occasional ,pap]s on ! ,!ory ( ,glaci]s1 ,ed9burgh1 #ahei4 ,w4 ,hopk9s1 ,on ! ,!ory ( ! ,motion ( ,glaci]s1 ,phil4 ,trans41 #ahfb1 p4 #fgg2 ,phil4 ,mag41 #ahfc1 ,vol4 ,,xxv1 p4 #bbd4 ,j4 ,tyndall1 ,=ms ( ,wat]1 ,new ,york1 #ahgb2 ,! ,glaci]s ( ! ,alps1 ,london1 #ahfa4 ,james ,croll1 ,on ! ,physical ,cause ( ! ,motion ( ,glaci]s1 ,phil4 ,mag41 #ahfi1 ,vol4 #ch1 pp4 #bja-f4 ,a4 ,heim1 ,on ,glaci]s1 ,phil4 ,mag41 #ahga1 ,vol4 #da1 pp4 #dhe-ejh2 ,h&bu* d] ,glets*]kunde1 #ahhe4 ,h4 ,moseley1 ,on ! ,cause ( ! ,desc5t ( ,glaci]s1 ,br4 ,assoc4 ,rept41 #ahfj1 ,pt4 #b1 p4 #dh2 also ,phil4 ,mag41 #ahfi1 ,vol4 #cg1 pp4 #bbi1 #cfc2 ,vol4 #ci1 p4 #bda2 ,vol4 #db1 p4 #ach2 ,vol4 #dc1 p4 #ch4 ,*4 ,grad1 ,la ,con/itution et le movem5t des ,glaci]s1 ,revue ,sci41 #ahgb4 ,h4 ,j4 ,r9k1 ,dani% ,gre5l&1 #ahgg4 ,r4 ,m4 ,deeley1 ,a ,!ory ( ,glacial ,motion1 ,phil4 ,mag41 #ahhh1 ,vol4 #be1 pp4 #acf-fd4 ,j4 ,c4 ,mc,connel1 ,on ! ,pla/icity ( an ,ice ,cry/al1 ,proc4 ,roy4 ,soc4 ,london1 ,vol4 #dh1 #ahij1 pp4 #bef-fj2 ibid41 ,vol4 #di1 #ahia1 pp4 #cbc-dc4 ,o4 ,mgge1 b] die ,pla/icitt d] ,eiskry/alle1 ,na*r4 k4 ,ges4 d4 ,wiss41 ,gtt+51 #ahie1 pp4 #a-d4 ,r4 ,m4 ,deeley & ,george ,flet*]1 ,! ,/ructure ( ,glaci] ,ice & its ,be>+s on ,glaci] ,motion1 ,geol4 ,mag4 7,london71 ,decade #d1 ,vol4 #b1 #ahie1 pp4 #aeb-fb4 ,t4 ,c4 ,*amb]l91 ,presid5tial address be=e ! ,geol4 ,soc4 ,am41 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,,vi1 ,febru>y #ahie1 pp4 #aii-bbj4 ,reid1 ,me*anics ( ,glaci]s1 ,j\r4 ,geol41 ,vol4 ,,iv1 #ahif1 p4 #iab4 ,eri* von ,drygalski1 ,grnl&-,exp$ition d] ,gesells*aft fr ,erdkunde zu ,b]l91 #ahia-ic1 ,vol4 ,i1 #ahig4 #ach ,mu* in=mation on ^! & o!r po9ts is to be f\nd 9 ! foll[+ books3 ,wild's ,?alassa2 ,?ompson's ,dep?s ( ! ,sea2 ,b>k]'s ,deep ,sea ,s\nd+s1 & ,maury's ,physical ,geography2 ,agassiz' ,! ,?ree ,cruises ( ! ,blake1 & ! ,*all5g] ,reports give mu* m detail$ in=mation conc]n+ ^! & o!r matt]s4 #aci ,dittm>1 ,*all5g] ,reports1 ,physics & ,*emi/ry1 ,vol4 ,i1 p4 #bjd4 #adj ,= a discussion ( ! way 9 :i* ?is gas is held 9 solution1 see ,tolman1 ,j\r4 ( ,geol41 ,vol4 ,,vii1 pp4 #eih-fah4 #ada ,murray1 ,scot4 ,geogr4 ,mag41 ,vol4 ,,iv1 p4 #ci4 #adb ,murray1 ,scot4 ,geogr4 ,mag41 ,vol4 ,,iii1 p4 #gf4 #adc ,ibid41 p4 #gj4 #add ,limit$ areas ( ! ocean bottom are actually concave upw>d2 t is1 !y are bas9s 9 ! m commonly accept$ s5se ( ! t]m 7see ,*apt] ,,ix74 #ade ,j4 ,geikie4 ,e>? ,sculpture1 p4 #cbi4 #adf ,murray4 ,scotti% ,geographical ,magaz9e1 ,vol4 ,,xv1 p4 #ejg4 #adg ,l9d5kohl4 ,sci5ce1 ,vol4 ,x1 #ahii1 p4 #hjg4 #adh ,?is does n hold = tropical latitudes4 #adi ,national ,geographic ,magaz9e1 ,vol4 ,,xi1 pp4 #cgg-cib4 #aej ,= causes ( ocean-curr5ts1 see ,croll's ,climate & ,"t2 ,proc4 ,roy4 ,soc41 #ahfi-gc1 & ,j\r4 ,roy4 ,geog4 ,soc41 #ahga-gg4 #aea ,9 ! foll[+ pages conc]n+ ! waves & _! "w ,gilb]t's classic discussion ( %ore features1 9 ! ,fif? ,annual ,report ( ! ,u4 ,s4 ,geol4 ,survey1 pp4 #hj-ajj1 is freely drawn on4 ,ano!r incisive discussion ( c]ta9 %ore ph5om5a is t ( ,f5neman1 ,j\r4 ( ,geol41 ,vol4 ,x1 pp4 #a-cb4 #aeb ,dana4 ,manual ( ,geology1 #d? ed41 p4 #bac4 #aec ,delesse4 ,li?ologie des ,m]s de ,france4 ,cit$ by ,geikie1 ,text-book ( ,geology1 #c;d ed41 p4 #dch4 #aed ,sir ,g4 ,airy4 ,encyclop$ia ,metropolitana1 ,art4 ,waves4 ,cit$ by ,geikie1 loc4 cit41 p4 #dch4 #aee ,/ev5son4 ,treatise on ,h>bors4 #aef ,willis4 ,j\r4 ( ,geol41 ,vol4 ,i1 p4 #dha4 #aeg ,/ev5son4 ,trans4 ,roy4 ,soc4 ,ed941 ,vol4 ,,xvi1 p4 #be4 ,treatise on ,h>bors1 p4 #db4 ,quot$ by ,geikie1 ,text-book ( ,geology1 p4 #dcg4 #aeh ,geikie4 ,text-book ( ,geology1 #c;d ed41 p4 #dcg4 #aei ,brit4 ,assoc4 ,rept41 #ahej1 p4 #bf4 #afj ,davis4 ,physical ,geography1 p4 #ced4 #afa ,dana4 ,manual ( ,geology1 #d? ed41 p4 #bai4 #afb ,%al]4 ,sea & ,l&1 p4 #bi4 #afc ,gulliv]1 ,%ore ,l9e ,topography3 ,proc4 ,am4 ,acad4 ,arts & ,sci41 ,vol4 ,,xxxiv1 #ahii1 pp4 #aea-beh4 ,a valuable /udy ( %ore-l9e topography4 #afd ,willis4 ,j\r4 ( ,geol41 ,vol4 ,i1 p4 #dha4 #afe ,see ,gilb]t4 ,topographic ,features ( ,lake ,%ores1 #e? 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,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i4 #ahi ,gilb]t1 ,lake ,bonneville1 ,mono4 ,i1 ,u4 ,s4 ,geol4 ,surv41 p4 #ga1 & ,topographic ,features ( ,lake ,%ores1 ,fif? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 p4 #aji4 #aij ,buckley4 ,wis4 ,acad4 ( ,sci41 ,vol4 ,,xiii1 ,pt4 ,i1 #aijj4 ,a /udy ( ice ramp>ts =m$ ab\t ! %ores ( ,lake ,m5dota1 ,wis41 9 #ahih-ii4 #aia ,copi$ f ,russell's ,lake ,lahontan1 ,mono4 ,,xi1 ,u4 ,s4 ,geol4 ,surv4 #aib ,less 4#jdbed c>bonic acid add$ to am\nt f\nd4 ,av]age ( two analyses4 #aic ,av]age f f\r analyses4 #aid ,av]age ( two analyses4 #aie ,z sesquic>bonates4 #aif ,z *loride4 #aig ,z p]oxide4 #aih ,c>bonic acid by diff]5ce4 #aii ,analyses ( ,rocks1 ,bull4 #afh1 ,u4 ,s4 ,geol4 ,surv41 #aijj1 p4 #ae4 #bjj ,quantitative ,classification ( ,igne\s ,rocks1 by ,:itman ,cross1 ,joseph ,p4 ,idd+s1 ,l\is ,v4 ,pirsson1 & ,h5ry ,s4 ,wa%+ton4 #aijc4 #bja ,van ,hise4 #af? ,ann4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 pp4 #ehi-id4 #bjb ,! application ( ^! pr9ciples we owe *iefly to ,van ,hise3 ,metamorphism ( ,rocks & ,rock ,fl[age1 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 #i1 pp4 #bfi-cbh4 #bjc ,cross1 ,idd+s1 ,pirsson1 & ,wa%+ton4 ,quantitative ,classification ( ,igne\s ,rocks4 #bjd ,! initials f4n4 7field names7 are introduc$ to %[ t ! t]m is us$ 9 ! broad field s5se propos$4 #bje ,add$ by ! au?ors ( ?is "w4 #bjf ,! foll[+ def9itions are giv51 z ne>ly z practicable1 9 accordance ) pres5t common usage1 :i* is1 h[ev]1 m or less v>y+ & inconsi/5t4 #bjg ,a compreh5sive discussion ( ! 8,g5esis ( ,ore ,deposits0 may be f\nd 9 ,vols4 ,,xxiii & ,,xxiv ( ! ,trans4 ( ! ,am4 ,in/4 ( ,m94 ,eng4 7also pr9t$ ) additions 9 book =m by ! ,in/itute1 #aijb71 9 :i* ,posepny1 ,emmons1 ,van ,hise1 ,le,conte1 ,blake1 ,beck]1 ,ric>d1 ,raymond1 ,l9dgr51 ,we$1 ,vogt1 ,w9sl[1 ,w9*ell 7,h4 ,v471 ,*ur*1 ,caz91 ,adams1 ,keyes1 ,ba91 ,coll9s1 ,beck1 & ,de,launay p>ticipat$4 ,v>i\s phases ( ! lead+ mod]n views are set =?4 #bjh ,*amb]l94 ,geol4 ( ,wis41 ,vol4 ,,iv1 p4 #eii et seq41 #ahhb4 #bji ,p5rose4 ,j\r4 ( ,geol41 ,vol4 ,,xi1 pp4 #ace-aee1 #aijc4 #baj ,van ,hise1 ,mono4 ,,xix1 ,u4 ,s4 ,geol4 ,surv41 pp4 #bfh-bie1 #ahib4 #baa ,gilb]t4 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,x1 pp4 #ace-adj1 #ahih4 #bab ,brann]4 ,j\r4 ( ,geol41 ,vol4 ,,viii1 pp4 #dha-dhd1 #aijj4 #bac ,idd+s4 ,j\r4 ( ,geol41 ,vol4 ,,vi1 pp4 #gjd-gaj4 #bad ,daubre4 ,gologie d',exprim5tale1 pp4 #cjf-cgb4 #bae ,crosby4 ,am]ican ,geologi/1 ,vol4 ,,xii1 #ahic1 pp4 #cfh-cge4 #baf ,beck]4 ,bull4 ,u4 ,s4 ,geol4 ,surv41 ,vol4 ,x1 pp4 #da-ge4 #bag ,van ,hise4 ,pr9ciples ( ,nor? ,am]ican ,pre-,cambrian ,geology4 #af? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 pp4 #ffh-fgb4 #bah ,dill]4 ,bull4 ,geol4 ,soc4 ,am41 ,vol4 ,i1 pp4 #dda-ddb4 ,ibid4 ,hay1 ,vol4 ,,iii1 pp4 #ej-ee2 & ,newsom1 ibid4 ,vol4 ,,xiv1 pp4 #bbg-bfh4 #bai ,willis4 ,bull4 ,geol4 ,soc4 ( ,am41 ,vol4 ,,xiii1 pp4 #cca-ccf4 #bbj ,mc,connell4 ,canada ,geol4 & ,nat4 ,hi/4 ,surv41 #ahhf1 ,pt4 ,,ii4 #bba ,geikie4 ,text-book ( ,geology4 #bbb ,beck]4 ,geology ( ! ,com/ock ,lode1 ,mono4 ,,iii1 ,u4 ,s4 ,geol4 ,surv41 ,*apt] ,,iv4 #bbc ,ref]5ce1 ,van ,hise4 ,sixte5? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 pp4 #fgb-fgh4 #bbd ,davison4 ,j\r4 ( ,geol41 ,vol4 ,,viii1 p4 #cja4 #bbe ,nature1 ,octob] #bd1 #ahie4 #bbf ,milne4 ,! ,geog4 ,j\r41 ,vol4 ,,xxi1 p4 #a4 ,see also ,seismology1 a m te*nical "w ?an ! same au?or's ,e>?quakes4 #bbg ,d>w94 ,j\rnal ( ,rese>*es1 #ahde1 p4 #cjc4 #bbh ,oldham4 ,qu>4 ,j\r4 ,geol4 ,soc41 ,vol4 ,,xxviii1 p4 #beg4 #bbi ,geikie4 ,text-book ( ,geology1 #d? ed41 p4 #cgb4 #bcj ,kot4 ,j\r4 ,coll4 ,sci41 ,japan1 ,vol4 ,v1 ,pt4 ,,iv 7#ahic71 pp4 #cbi1 #cci4 ,cit$ by ,geikie1 loc4 cit41 p4 #cgc4 #bca ,an elaborate acc\nt ( ?is e>?quake is giv5 by ,dutton1 ,n9? ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 pp4 #bji-ebh4 #bcb ,cross4 ,tw5ty-fir/ ,ann4 ,rept41 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,ii1 ,*ap4 ,v4 #bcc ,oldham4 ,report on ! ,indian ,e>?quake ( ,june #ab1 #ahig1 p4 #ach4 ,mem4 ,geol4 ,surv4 ( ,india4 ,cit$ by ,geikie1 loc4 cit41 p4 #cgd4 #bcd ,oldham1 loc4 cit41 p4 #hj4 #bce ,geikie4 ,text-book ( ,geology1 #d? ed41 p4 #cge4 #bcf ,ibid41 p4 #cgf4 #bcg ,=/]1 ,seismology1 #ahgg4 ,summ>iz$ 9 ! ,am4 ,geol41 ,vol4 ,,iii1 #ahhi1 p4 #ahb4 #bch ,! lit]ature ( seismology is v ext5sive4 ,"s ( ! m g5]al treatises are ! foll[+3 ,mallet1 ,brit4 ,assoc41 #ahdg1 ,"p ,,ii1 p4 #cj2 #ahej1 p4 #a2 #ahea1 p4 #bgb2 #aheb1 p4 #a2 #aheh1 p4 #a2 #ahfa1 p4 #bja2 & ,! ,great ,neapolitan ,e>?quake ( #aheg1 #b ,vols41 #ahfb2 ,a4 ,p]rey1 ,mm4 ,c\ronn4 ,bruxelles1 ,,xviii 7#ahdd71 ,comptes ,r5dus1 ,,lii1 p4 #adf2 ,r4 ,falb1 ,grundzge e9] ,!orie d] ,erdbeb5 und ,vulkan5ausbr*e1 ,graz1 #ahga1 & ,g$ank5 und ,/udi5 b] d5 ,vulkanismus1 etc41 #ahgd2 ,pfaff1 ,allgeme9e ,geologie als exacte ,wiss5s*aft1 ,leipzig1 #ahgc1 p4 #bbd2 ,s*midt1 ,/udi5 b] ,erdbeb51 #b;d ed41 #ahgi1 & ,/udi5 b] ,vulkane und ,erdbeb51 #ahha2 ,dieff5ba*1 ,neues ,jahrb41 #ahgb1 p4 #aee2 ,m4 ,s4 di ,rossi1 ,la ,meteorologia ,endog5a1 #b ,vols41 #ahgi & #ahhb2 ,j4 ,milne1 ,e>?quakes & o!r ,e>?-movem5ts 7conta9s a bibliography71 #d? ed41 #ahih2 ,seismology1 ibid41 #ahih2 ,dutton1 ,e>?quakes1 #aijd4 ,records ( e>?quakes h be5 pres]v$ m or less fully 9 sev]al c\ntries1 especially 9 rec5t ye>s4 ,a few ( ! m accessible publications :]e ^! records are f\nd are cit$ bel[3 ,cali=nia e>?quakes1 ,p]r9e1 ,bull4 #adg1 ,u4 ,s4 ,geol4 ,surv42 ,e>?quakes ( ! ,pacific ,coa/1 ,hold51 ,smi?son4 ,misc4 ,coll41 ,no4 #ajhg1 #ahih2 ,records ( rec5t e>?quake movem5ts 9 ,great ,brita9 s9ce #ahij are publi%$ by ,davison 9 ,qu>4 ,j\r4 ,geol4 ,soc41 ,geol4 ,mag41 & ,nature2 ,records ( e>li] e>?quakes are f\nd 9 ! reports ( ! ,brit4 ,assoc4 7,mallet71 9 ! ,ed9burgh ,new ,philos4 ,j\r41 ,vols4 ,,xxxi-,,xxxvi 7,milne71 & 9 ,trans4 ( ! ,roy4 ,iri% ,acad41 #ahhd & #ahhf 7,o',reilly72 ,! ,e>?quakes ( ,sc&9avia h be5 record$ 9 volumes ( ! ,geol4 ,fr51 ,frh&l42 ,records ( o!r cont95tal ,european e>?quakes are f\nd 9 ,g]l&'s ,beitrge zur ,geophysik1 #ahie1 #aijj1 & #aija2 ,neues ,jahrb41 #ahfe-ga2 ,zeits*r4 ,naturwiss54 7#ahhd71 7,cr$n]72 ,b]i*t4 k4 ,sa*s4 ,geol4 ,wiss541 #ahhi & #aijj 7,cr$n]72 ,jahrb4 ,geol4 ,rei*san/41 #ahie & #ahig2 ,ts*]mak's ,m94 ,mit?41 #ahgc1 & lat]2 ,transactions ( ! ,seismological ,soc4 ( ,japan4 ,an index to ^! ,transactions is giv5 at ! end ( ,milne's ,seismology4 #bci ,antlitz d] ,erde4 ,vol4 #a1 p4 #acf4 #bdj ,eug5e ,a4 ,smi?4 ,und]?ru/ ,folds & ,faults1 ,am4 ,j\r4 ,sci41 ,vol4 ,,xlv1 #ahic1 pp4 #cje-f4 #bda ,manual ( ,geology1 #c;d ed41 p4 #bc4 #bdb ,= discussions ( folds1 see ,van ,hise1 ,sixte5? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 pp4 #fjc-fcb2 & ,willis1 ,?irte5? ,ann4 ,rept41 ,pt4 ,,ii1 pp4 #bag-bif4 #bdc ,me*anismus d] ,gebirgsbildung1 p4 #bac4 #bdd ,am4 ,nat41 ,vol4 ,,xix1 p4 #beg1 #ahhe4 #bde ,geol4 ,surv4 ( ,canada1 p4 #cc ,d1 #ahhf4 #bdf ,elem5ts ( ,geology1 #e? ed41 p4 #bff4 #bdg ,van ,hise4 ,bull4 ,geol4 ,soc4 ( ,am41 #ahig1 ,vol4 ,,ix1 p4 #bia4 #bdh ,see ,woodw>d's address1 ,ma!matical ,!ories ( ! ,e>?1 ,proc4 ,am4 ,assc4 = ,adv4 ,sci41 #ahhi1 pp4 #ei-fc4 #bdi ,nat4 ,phil4 ,?ompson & ,tait1 ,pt4 ,,ii1 p4 #dgg4 ,see also ,popul> ,lectures & ,addresses1 #ahid1 ,,ii1 p4 #cac4 #bej ,physics ( ! ,e>?'s ,cru/1 ,fi%]1 p4 #ie4 #bea ,orig9 ( ,m\nta9 ,ranges1 ,t4 ,mell>d ,reade1 p4 #abe4 #beb ,phil4 ,trans4 ,roy4 ,soc41 ,vol4 #agh1 pp4 #bca-di4 #bec ,am]4 ,j\r4 ,sci41 #ahic1 #c;d s]ies1 ,vol4 #de1 p4 #g4 #bed ,ess5tially ! same z atmosph]es4 #bee ,! pressures & d5sities "h giv5 are ess5tially ! same z ^? previ\sly work$ out by o!rs & already publi%$4 ,! temp]atures are ! results ( rec5t prelim9>y computations made "u ! auspices ( ! ,c>negie ,in/itution1 & are subject to *ange on fur!r /udy4 ,!y are bas$ on ! assumption t ! increase 9 d5sity is due to compression4 ,!y are 9 g5]al accord ) ! results previ\sly rea*$ by ,dr4 ,f4 ,r4 ,m\lton 7see 8,a ,gr\p ( ,hypo!ses ,be>+ on ,climatic ,*anges10 by ,t4 ,c4 ,*amb]l91 ,j\r4 ( ,geol41 #ahig1 p4 #fgd74 ,! ,rev4 ,o4 ,fi%]1 9 ! ,am4 ,j\r4 ( ,sci41 #aija1 p4 #dbj1 gives mu* high] results4 #bef ,att5tion 0 call$ to ?is feature by ,*amb]l9 9 a pap] be=e ! ,geol4 ,soc4 ( ,am4 at ,ro*e/]1 ,decemb]1 #aija4 #beg ,^! are reckon$ by assum+ t ! temp]ature ( no v>iation at #ej feet bel[ ! surface is #dj ,f4 #beh ,am4 ,j\r4 ( ,sci41 ,vol4 ,v1 #ahih1 p4 #afa4 #bei ,van ,hise4 ,p]sonal communication4 #bfj ,bull4 #afh ,u4 ,s4 ,geol4 ,surv41 p4 #ad4 #bfa ,daniell's ,physics1 p4 #djg4 #bfb ,heat4 ,tait1 p4 #bbe4 #bfc ,all ! feldsp>s are calculat$ z anor?ite4 ,augite is us$ = hyp]/h5e1 ilm5ite is includ$ ) magnetite1 & all m9]als are calculat$ z if ( ! isometric sy/em4 #bfd ,physics ( ! ,e>?'s ,cru/1 ,*ap4 ,,viii4 #bfe ,p5n ,mon?ly1 ,philadelphia1 ,may1 #ahgf4 #bff ,! foll[+ conclusion by an em95t au?ority has come to our notice s9ce ?is 0 writt53 ,l'influ5ce des m>es ocani5es sur la dure du j\r e/ donc t\t fait m9ime et n'e/ nullem5t comp>able l'effet des m>es dues la viscosit et l'ela/icit de la p>tie solide du globe1 effet sur lequel ,m4 ,d>w9 insi/ dans une s]ies de ,mmoires du plus haut intrt4 ,p> ,h4 ,po9c>1 ,bullet9 ,a/ronomique1 tome ,,xx 7,june1 #aijc71 p4 #bbc4 #bfg ,on ! ,secul> ,*anges 9 ! ,elem5ts ( ! ,orbit ( a ,satellite revolv+ ab\t a ,tidally-di/ort$ ,planet4 ,phil4 ,trans41 ,roy4 ,soc41 ,pt4 ,,ii1 #ahhj4 #bfh ,j\r4 ,geol41 ,vol4 ,,vi1 #ahih1 p4 #fe4 #bfi ,qu>4 ,j\r4 ,geol4 ,soc41 ,vol4 #ci1 #ahhc1 p4 #adj4 ,ev]ett 7,units & ,physical ,con/ants7 gives #hcg #aj = /eel1 b z ! modulus = granite seems l[1 we h tak5 ! l[] e/imate = /eel to avoid exagg]at+ ! ratio betwe5 !m4 #bgj ,nat4 ,phil4 ,?ompson ,tait1 ,vol4 ,,ii1 p4 #dbd1 #ahij4 #bga ,computations made at ! reque/ ( ! au?ors4 ,see also ,fi%]1 ,physics ( ! ,e>?'s ,cru/1 p4 #cf4 #bgb ,( l import is ! /atem5t ( ,woodw>d--8,if ! cru/ ( ! e>? 7 self-support+1 its cru%+ /r5g? w\ld h to be ab\t ?irty times t ( ! be/ ca/ /eel1 or five hundr$ to "o ?\s& times t ( granite40 ,ma!matical ,!ories ( ! ,e>?1 ,proc4 ,am4 ,assoc4 = ,adv4 ,sci41 #ahhi1 p4 #di4 #bgc ,x is assum$ t ! direction ( ! support+ ?ru/ at ! p]iph]y ( ! dome is at e po9t p>allel to ! tang5t to ! dom$ surface4 ,?is is ju/ifi$ by symmetry 9 ! case ( a %ell con=m+ to ! sph]icity ( ! e>?1 & 9 ! o!r cases x w\ld seem to be z favorable an assumption 9 ! direction ( high support+ capacity z c reasonably be made4 #bgd ,prep>$ at ! au?ors' reque/ by ,w4 ,h4 ,emmons4 #bge ,! t]ms are "h us$ 9 _! n>r[ te*nical s5se4 ,extrusion is also us$ 9 a broad g5]ic s5se to indicate ! :ole process ( outw>d movem5t4 #bgf ,gilb]t4 #ad? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,i1 p4 #ahg4 #bgg ,gilb]t1 aft] a c>eful /udy ( ! moon's topography1 has sugge/$ t ! lun> pits may be ind5tations produc$ by infall+ meteorites or planetoids1 & has %[n by exp]im5t t pits ( a simil> type1 ) simil> c5tral cones1 c be produc$ by impact4 ,! ,moon's ,face3 ,a ,/udy ( ! ,orig9 ( its ,features4 ,presid5tial address1 ,phil4 ,soc4 ( ,wa%+ton1 #ahib1 ,bull4 ,vol4 ,,xii1 pp4 #bda-bib4 #bgh ,/ructure & ,di/ribution ( ,coral ,isl&s4 #bgi ,corals & ,coral ,isl&s4 #bhj ,proc4 ,roy4 ,soc4 ,ed941 ,vol4 ,x1 pp4 #eje-ah1 & ,vol4 ,,xvii1 pp4 #gi-aji2 ,nature1 ,vol4 ,,xxxii1 p4 #fac2 ,n>rative ,*al4 ,exp41 ,vol4 ,i1 pp4 #gha-b4 #bha ,bull4 ,mus4 ,comp4 ,zool41 ,vol4 ,,xvii1 #ahhi4 #bhb ,ante1 p4 #bb4 #bhc ,orig9 ( ,igne\s ,rocks4 ,phil4 ,soc4 ( ,wa%41 ,vol4 ,,xii1 pp4 #hi-bad4 #bhd ,! ,natural ,sy/em ( ,volcanic ,rocks4 ,cal4 ,acad4 ( ,sci41 #ahfh4 #bhe ,*emical ,news1 ,april #i1 #ahig4 #bhf ,phil4 ,trans41 #ahgc4 #bhg ,me*anics ( ,igne\s ,intrusion1 ,am4 ,j\r4 ,sci41 ,apr41 p4 #bfi1 & ,aug41 p4 #ajg1 #aijc4 #bhh ,frank4 ,lehrbu* d] ,botanik1 ,i1 p4 #egf1 #ahib4 #bhi ,sci5ce1 ,vol4 ,,vi1 p4 #hch1 #ahig4 ,zeits*rift fr ,anorganis*e ,*emie1 #ahig4 #bij ,ref]5ce works3 ,scott1 ,/udies 9 ,fossil ,plants1 #aijj2 ,zeill]1 lm5ts de ,palobotanique1 #aijj2 ,potoni1 ,lehrbu* d] ,pflanz5paleontologie1 #ahii2 ,sew>d1 ,fossil ,plants1 #ahih2 ,solms-,lauba*1 ,fossil ,botany1 #ahhg4 #bia ,we$4 ,n9? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhg-hh1 pp4 #fac-gf2 also ,bradley ,m4 ,davis4 ,sci5ce1 ,vol4 ,,vi1 #ahig1 pp4 #ade-eg4 #bib ,cohn4 ,abh&l4 ,s*les4 ,gesell4 ,naturwiss41 ,heft ,,ii1 #ahfb4 #bic ,deep ,sea ,deposits1 p4 #beg4 #bid ,c4 ,a4 ,davis4 ,j\r4 ( ,geol41 ,vol4 ,,ix1 #aija1 p4 #dia4 #bie ,we$4 ,n9? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhg-h4 #bif ,ref]5ce books3 ,zittel's ,text-book on ,paleontology1 translat$ & edit$ by ,ea/man2 ,williams' ,geological ,biology2 ,ni*olson's ,manual ( ,paleontology4 #big ,aft] ,zittel 9 ! ma94 #bih ,s4 ,w4 ,johnson1 ,h[ ,crops ,fe$1 p4 #dg4 #bii ,ref]5ce works3 ,plant ,relations1 ,c\lt]1 #aijj1--;a conv5i5t elem5t>y "w2 ,s*imp]1 ,pflanz5geographie1 #ahih2 ,w>m+1 ,lehrbu* d] oekologis*5 ,pflanz5geographie1 #ahif2 ,c[les1 ,botanical ,gazette1 ,vol4 ,,xxvii1 #ahih4 #cjj ,"o ( ! e>lie/ attempts to map ^! & develop _! significance & value is f\nd 9 ,vol4 ,,ii1 ,geol4 ( ,wis41 #ahgc-gg1 ,native ,vegetation1 pp4 #agf-hg4 #cja ,*amb]l94 ,a ,sy/ematic ,s\rce ( ,evolution ( ,prov9cial ,faunas1 ,j\r4 ( ,geol41 ,vol4 ,,vi1 #ahih1 pp4 #eig-fji4 #cjb ,wallace4 ,isl& ,life4 #cjc ,= data1 see ,wal!r's ,e9leitung 9 die ,geologie1 pp4 #ce-de4 ,transcrib]'s ,notes3 - ,text enclos$ by und]scores is 9 italics 7italics74 - ,text enclos$ by equals is 9 antiqua font 7antiqua74 - ,text enclos$ by pluses is 9 small caps 7,small ,caps74 - ,blank pages h be5 remov$4 - ,obvi\s typographical errors h be5 sil5tly correct$4