includes ! m ?an #ejj orig9al illu/rations4 ,see #ejfga-;h4htm or #ejfga-;h4zip3 7https3_/_/www4gut5b]g4org_/ca*e_/epub_/ #ejfga_/pg#ejfga-;images4html7 or 7https3_/_/www4gut5b]g4org_/files_/#ejfg a_/ejfga-;h4zip7 ,images ( ! orig9al pages are available ?r\gh ,int]net ,ar*ive4 ,see https3_/_/ar*ive4org_/details_/cu#caibdj jdigegfc ,transcrib]'s note3 ,text enclos$ by und]scores is 9 italics 7italics74 ,text enclos$ by equal signs is 9 bold face 7bold74 ,a c>at "* is us$ to d5ote sup]scription4 ,a s+le "* foll[+ ! c>at is sup]script$ 7example3 b#a74 ,multiple sup]script$ *>act]s are enclos$ by curly brackets 7example3 #a-b74 ,subscript numb]s 9 *emical =mulas h be5 r5d]$ z n or n4 ,,e>? ,,features ,,& ,,_! ,,mean+ 99 99 99 99 99 99 ,illu/ration3 ,,logo ,! ,macmillan ,company ,new ,york ,bo/on ,*icago ,dallas ,san ,francisco ,macmillan ,co41 ,limit$ ,london ,bombay ,calcutta ,melb\rne ,! ,macmillan ,co4 ,( ,canada1 ,ltd4 ,toronto 99 99 99 99 99 99 ---------------------------------------- --------------------- ,,plate #a4 ,illu/ration3 ,m\nt ,balf\r & ! ,balf\r ,glaci] 9 ! ,selkirks4 ---------------------------------------- --------------------- ,,e>? ,,features ,,& ,,_! ,,mean+ ,an ,introduction to ,geology = ! ,/ud5t & ! ,g5]al ,read] by ,,william ,,h]b]t ,,hobbs ,pr(essor ( ,geology 9 ! ,univ]sity ( ,mi*igan ,au?or ( 8,e>?quakes4 an ,introduction to ,seismic ,geology02 8,*>act]i/ics ( ,exi/+ ,glaci]s02 etc4 ,new ,york ,! ,macmillan ,company #aiba ,all rights res]v$ ,copyright1 #aiab1 ,by ,! ,macmillan ,company4 ,norwood ,press ,j4 ,s4 ,cu%+ ,co4--,b]wick ,smi? ,co4 ,norwood1 ,mass41 ,u4,s4,a4 ,,to ,,! ,,memory ,,( ,,george ,,hunt+ton ,,williams ,,preface ,,! s]ies ( read+s conta9$ 9 ! pres5t volume give 9 some:at exp&$ =m ! sub/ance ( a c\rse ( illu/rat$ lectures :i* has n[ = sev]al ye>s be5 deliv]$ ea* seme/] at ! ,univ]sity ( ,mi*igan4 ,! keynote ( ! c\rse may be f\nd 9 ! dom9ant *>act]i/ics ( ! diff]5t e>? features & ! geological processes :i* h be5 betray$ 9 ! %ap+ ( !m4 ,su* a geological exam9ation ( l&scape is replete ) fasc9at+ revelations1 & x l5ds to ! /udy ( ,nature a deep mean+ :i* _c b enhance ! enjoym5t ( h] v>i$ aspects4 ,t !re is a real place = su* a cultural /udy ( geology )9 ! ,univ]sity is believ$ to be %[n by ! increas+ numb] ( /ud5ts :o h elect$ ! "w4 ,ev5 m ?an 9 =m] ye>s ! ,am]ican travels af> by c> or /eam%ip1 & ! e>?'s surface features 9 all _! manifold div]sity are ?us "o aft] ! o!r unroll$ be=e him4 ,! ?\s&s :o ea* ye> cross ! ,atlantic to roam ov] ,european c\ntries may by hi/orical1 lit]>y1 or arti/ic /udies prep>e !mselves to d]ive an exquisite pleasure z !y visit places id5tifi$ ) pa/ a*ievem5t ( "o =m or ano!r4 ,yet ! ,*annel coa/1 ! gorge ( ! ,rh9e1 ! glaci]s ( ,switz]l&1 & ! wild sc5]y ( ,norway or ,scotl& h ea* _! fasc9at+ /ory to tell ( a hi/ory f> m remote & v>i$4 ,to read ?is hi/ory1 ! runic *>act]s 9 :i* x is writt5 mu/ fir/ ( all be ma/]$2 = 9 e l&scape !re are /rong individual l9es ( "* su* z ! p5 arti/ w\ld skillfully extract = an outl9e sket*4 ,su* "* pr(iles are (t5 _m times repeat$ 9 ea* l&scape1 & 9 !m we h a key to ! hi/orical record4 ,an object ( ! pres5t read+s has ?us be5 to enable ! /ud5t to himself pick out 9 ea* l&scape ^! m significant l9es & s read directly f ,nature4 ,9 ! l&scapes :i* h be5 repres5t$1 ! aim has be5 to draw z f> z possible ^u localities well kn[n to travel]s & likely to be visit$1 ei!r because ( _! hi/orical int]e/ or _! purely sc5ic attractions4 ,x %\ld ?us be possible = a t\ri/ 9 ,am]ica or ,europe to pursue 8 l&scape /udies :5ev] he sets out ^u 8 travels4 ,! bett] to aid him 9 ?is endeavor1 "s sugge/ions conc]n+ ! it9]>y ( j\rneys h be5 suppli$ 9 an app5dix4 ,reg>d$ z a textbook ( geology1 ! pres5t "w (f]s "s dep>tures f exi/+ examples4 ,?\gh x has be5 cu/om>y to comb9e 9 a s+le text hi/orical ) dynamical & /ructural geology1 a t5d5cy has already become app>5t to treat ! hi/orical division ap>t f ! o!rs4 ,aga91 a desire to treat ! sci5ce ( geology compreh5sively has l$ "s au?ors into includ+ s _m subjects z to r5d] _! texts unnecess>ily encyclop$ic & correspond+ly un9t]e/+ to ! g5]al read]4 ,x is ! au?or's belief t !re is a real ne$ = a book :i* may be read intellig5tly by ! g5]al public1 & x mu/ be recogniz$ t ! beg9n] 9 ! subject _c cov] ! entire field by a s+le c\rse ( read+s4 ,! pres5t "w has1 !re=e1 be5 prep>$ ) a view to select+ = /udy ^? dom9ant geological processes :i* are be/ illu/rat$ by features 9 nor!rn ,nor? ,am]ica & ,europe4 ,x is ?is desire to illu/rate ! read+s by travels afield1 :i* acc\nts = ! prom95ce giv5 to ! subject ( glaciation2 = ! l>g] numb] ( colleges & univ]sities 9 bo? ,am]ica & ,europe are surr\nd$ by ! heavy accumulations t h result$ f =m] glaciations4 ,emphasis has also be5 plac$ ^u ! dep5d5ce ( ! dom9ant geological processes ( any region ^u exi/+ climatic conditions1 a fact to :i* too little att5tion has g5]ally be5 giv54 ,?is expla9s ! r full treatm5t ( des]t regions1 ( :i*1 9 our own c\ntry p>ticul>ly1 mu* may be illu/rat$ ^u ! transcont95tal railway j\rneys4 ,m ?an 9 mo/ texts ! attempt has "h be5 made to tea* directly ?r\gh ! eye ) ! effici5t aid ( apt illu/rations intimately int]wov5 ) ! text4 ,= su* success z has be5 rea*$ 9 ?is endeavor1 ! au?or is greatly indebt$ to two /ud5ts ( ! ,univ]sity ( ,mi*igan1--,mr4 ,james ,h4 ,mei]1 :o has prep>$ ! l9e draw+s ( l&scapes1 & ,mr4 ,hugh ,m4 ,pi]ce1 :o has draught$ ! diagrams4 ,?\gh cr$it has 9 mo/ cases be5 giv5 :]e illu/rations h be5 made f ano!r's photographs1 yet especial m5tion %\ld "h be made ( ! debt to ,dr4 ,h4 ,w4 ,fairbanks ( ,b]keley1 ,cali=nia1 ^: beautiful & in/ructive photographs are reproduc$ ^u _m a page4 ,z giv5 at ! ,univ]sity ( ,mi*igan1 ! lectures reflect$ 9 ! pres5t volume are supplem5t$ by excursions & by s mu* laboratory practice z is necess>y to become famili> ) ! m common m9]als & rocks1 & to read intellig5tly ! usual topographical & geological maps4 ,9 ! app5dices ! means = c>ry+ out su* /udies1 9 "p ) newly devis$ app>atus1 h be5 indicat$4 ,! scope ( ! book precludes ! possibility ( furni%+ ! read] ) ! s\rces = ! body ( fact & !ory :i* is pres5t$1 al?\gh mu* may be inf]r$ f ! names :i* appe> b5ea? ! illu/rations1 & m def9ite k w be f\nd 9 ! ref]5ces to lit]ature suppli$ at ! ends ( *apt]s4 ,a l>ge am\nt ( orig9al & unpubli%$ mat]ial is = a simil> reason unlabel$1 & x has be5 left = ! pr(essional geologi/ to detect ^! new /r&s :i* h be5 drawn into ! web4 ,,william ,,h]b]t ,,hobbs4 ,,ann ,,arbor1 ,,mi*igan1 ,octob] #be1 #aiaa4 ,,cont5ts ,,*apt] ,i ,,! ,,compilation ,,( ,,e>? ,,hi/ory ,,page ,! s\rces ( ! hi/ory--,subdivisions ( geology--,! /udy ( e>? features & _! significance--,tabul> recapitulation--,geological processes n univ]sal--,*ange1 & n /ability1 ! ord] ( nature--,obs]vational geology v]sus speculative philosophy--,! sci5tific attitude & temp]--,! value ( ! hypo!sis--,head+ ref]5ces #a ,,*apt] ,,ii ,,! ,,figure ,,( ,,! ,,e>? ,! li?osph]e & its envelopes--,! evolution ( ideas conc]n+ ! e>?'s figure--,! oblat5ess ( ! e>?--,! arrangem5t ( oceans & cont95ts--,! figure t[>d :i* ! e>? is t5d+--,a/ronomical v]sus geodetic obs]vations--,*anges ( figure dur+ contraction ( a sph]ical body--,! e>li] figures ( ! e>?--,! cont95ts & oceans at ! close ( ! ,paleozoic era--,! flood$ portions ( ! pres5t cont95ts--,! floors ( ! hydrosph]e & atmosph]e--,read+ ref]5ces #h ,,*apt] ,,iii ,,! ,,nature ,,( ,,! ,,mat]ials ,,9 ,,! ,,li?osph]e ,! rigid quality ( our planet--,probable composition ( ! e>?'s core--,! e>? a magnet--,! *emical con/itution ( ! e>?'s surface %ell--,! ess5tial nature ( cry/als--,! li?osph]e a complex ( int]lock+ cry/als--,"s prop]ties ( natural cry/als1 m9]als--,! alt]ations ( m9]als--,read+ ref]5ces #bj ,,*apt] ,,iv ,,! ,,rocks ,,( ,,! ,,e>?',s ,,surface ,,%ell ,! processes by :i* rocks are =m$--,! m>ks ( orig9--,! metamorphic rocks--,*>act]i/ic textures ( ! igne\s rocks--,! classification ( rocks--,subdivisions ( ! s$im5t>y rocks--,! diff]5t deposits ( ocean1 lake1 & riv]--,special m>ks ( littoral deposits--,! ord] ( deposition dur+ a transgression ( ! sea--,! bas9s ( deposition ( e>li] ages--,! deposits ( ! deep sea--,read+ ref]5ces #cj ,,*apt] ,v ,,contortions ,,( ,,! ,,/rata ,,)9 ,,! ,,zone ,,( ,,fl[ ,! zones ( fracture & fl[--,exp]im5ts :i* illu/rate ! fracture & fl[ ( solid bodies--,! ar*es & tr\ghs ( ! fold$ /rata--,! elem5ts ( folds--,! %apes ( rock folds--,! ov]?ru/ fold--,re/oration ( mutilat$ folds--,! geological map & section--,measurem5t ( ! ?ickness ( =mations--,! detection ( plung+ folds--,! mean+ ( an uncon=mity--,read+ ref]5ces #dj ,,*apt] ,,vi ,,! ,,ar*itecture ,,( ,,! ,,fractur$ ,,sup]/ructure ,! sy/em ( ! fractures--,! space int]vals ( jo9ts--,! displacem5ts ^u jo9ts3 faults--,me?ods ( detect+ faults--,! base ( ! geological map--,! field map & ! areal geological map--,laboratory models = /udy ( geological maps--,! me?od ( prep>+ ! map--,fold vs4 fault topography--,read+ ref]5ces #ee ,,*apt] ,,vii ,,! ,,int]rupt$ ,,"* ,,( ,,e>? ,,movem5ts3 ,,e>?quakes ,,& ,,seaquakes ,nature ( e>?quake %ocks--,seaquakes & seismic sea waves--,! gr&] & ! less] e>? movem5ts--,*anges 9 ! e>?'s surface dur+ e>?quakes3 faults & fissures--,! measure ( displacem5t--,contraction ( ! e>?'s surface dur+ e>?quakes--,! plan ( an e>?quake fault--,! block movem5ts ( ! di/urb$ di/rict--,! e>? blocks adju/$ dur+ ! ,alaskan e>?quake ( #ahii #fg ,,*apt] ,,viii ,,! ,,int]rupt$ ,,"* ,,( ,,e>? ,,movem5ts3 ,,e>?quakes ,,& ,,seaquakes 7conclud$7 ,exp]im5tal demon/ration ( e>? movem5ts--,d]angem5t ( wat] fl[ by e>? movem5t--,s& or mud cones & crat]lets--,! e>?'s zones ( heavy e>?quake--,! special l9es ( heavy %ock--,seismotectonic l9es--,! heavy %ocks above loose f\ndations--,con/ruction 9 e>?quake regions--,read+ ref]5ces #ha ,,*apt] ,,ix ,,! ,,rise ,,( ,,molt5 ,,rock ,,to ,,! ,,e>?',s ,,surface2 ,,volcanic ,,m\nta9s ,,( ,,exudation ,preval5t misconceptions ab\t volcanoes--,e>ly views conc]n+ volcanic m\nta9s--,! bir? ( volcanoes--,active & ext9ct volcanoes--,! e>?'s volcano belts--,arrangem5t ( volcanic v5ts along fissures1 & especially at _! int]sections--,! s-call$ fissure eruptions--,! composition & ! prop]ties ( lava--,! ?ree ma9 types ( volcanic m\nta9--,! lava dome--,! basaltic lava domes ( ,hawaii--,lava movem5ts )9 ! caldron ( ,kilauea--,! dra9+ ( ! lava caldrons--,! outfl[ ( ! lava floods #id ,,*apt] ,x ,,! ,,rise ,,( ,,molt5 ,,rock ,,to ,,! ,,e>?',s ,,surface2 ,,volcanic ,,m\nta9s ,,( ,,eject$ ,,mat]ials ,! me*anics ( crat] explosions--,gr&] volcanic eruptions ( c9d] cones--,! eruption ( ,volcano 9 #ahhh--,! eruption ( ,taal volcano on ,janu>y #cj1 #aiaa--,! mat]ials & ! /ructure ( c9d] cones--,! pr(ile l9es ( c9d] cones--,! composite cone--,! cald]a ( composite cones--,! eruption ( ,vesuvius 9 #aijf--,! sequ5ce ( ev5ts )9 ! *imney--,! sp9e ( ,pel--,! aft]ma? ( mud fl[s--,! dissection ( volcanoes--,! =mation ( lava res]voirs--,"* pr(iles--,read+ ref]5ces #aae ,,*apt] ,,xi ,,! ,,attack ,,( ,,! ,,wea!r ,! two contra/$ processes ( wea!r+--,! rle ( ! p]colat+ wat]--,me*anical results ( decomposition3 sph]oidal wea!r+--,exfoliation or scal+--,dome /ructure 9 granite masses--,! pry+ "w ( fro/--,talus--,soil fl[ 9 ! cont9u$ pres5ce ( ?aw wat]--,! splitt+ w$ges ( roots & trees--,! rock mantle & its %ield 9 ! mat ( vegetation--,read+ ref]5ces #adi ,,*apt] ,,xii ,,! ,,life ,,hi/ories ,,( ,,riv]s ,! intricate patt]n ( riv] et*+s--,! motive p[] ( riv]s--,old l& & new l&--,! e>li] aspects ( riv]s--,! me%es ( ! riv] network--,! upp] & l[] rea*es ( a riv] contra/$--,! balance betwe5 degradation & aggradation--,! accordance ( tribut>y valleys--,! grad+ ( ! flood pla9--,! cycles ( /ream me&]s--,! cut-(f ( ! me&]--,me&] sc>s--,riv] t]races--,! delta ( ! riv]--,! levee--,! sections ( delta deposits #aeh ,,*apt] ,,xiii ,,e>? ,,features ,,%ap$ ,,by ,,runn+ ,,wat] ,! newly incis$ upl& & its %>p sali5ts--,! /age ( adolesc5ce--,! maturely dissect$ upl&--,! ,hog>?ian l9e ( beauty--,! f9al product ( riv] sculpture3 ! p5epla9--,! riv] cross sections ( successive /ages--,! entr5*m5t ( me&]s ) r5ew$ uplift--,! valley ( ! rejuv5at$ riv]--,! arre/ ( /ream erosion by ! m resi/ant rocks--,! capture ( "o riv] by ano!r--,wat] & w9d gaps--,"* pr(iles--,read+ ref]5ces #afi ,,*apt] ,,xiv ,,! ,,travels ,,( ,,! ,,und]gr\nd ,,wat] ,! desc5t )9 ! unsaturat$ zone--,! trunk *annels ( desc5d+ wat]--,! cav]ns ( lime/ones--,swall[ holes & lime/one s9ks--,! s9t] deposits--,! gr[? ( /alactites--,=mation ( /alagmites--,! ,k>/ & its features--,a des]t f ! de/ruction ( =e/s--,! ponore & ! polje--,! return ( ! wat] to ! surface--,artesian wells--,hot spr+s & geys]s--,! deposition ( silice\s s9t] by plant gr[?--,read+ ref]5ces #ahj ,,*apt] ,,xv ,,sun ,,& ,,w9d ,,9 ,,! ,,l&s ,,( ,,infrequ5t ,,ra9s ,! law ( ! des]t--,! self-regi/]+ gauge ( pa/ climates--,"s *>act]i/ics ( ! des]t wa/e--,dry wea!r+3 ! r$ & br[n des]t v>ni%--,! me*anical breakd[n ( ! des]t rocks--,! natural s& bla/--,! du/ c>ri$ out ( ! des]t #aig ,,*apt] ,,xvi ,,! ,,features ,,9 ,,des]t ,,l&scapes ,! w&]+ dunes--,! =ms ( dunes--,! cl\dbur/ 9 ! des]t--,! zone ( ! dw9dl+ riv]--,erosion 9 & ab\t ! des]t--,*>act]i/ic features ( ! arid l&s--,! w> ( dune & oasis--,! orig9 ( ! high pla9s :i* front ! ,rocky ,m\nta9s--,"* pr(iles--,read+ ref]5ces #bji ,,*apt] ,,xvii ,,repeat+ ,,patt]ns ,,9 ,,! ,,e>? ,,relief ,! wea!r+ processes "u control ( ! fracture sy/em--,! fracture control ( ! dra9age l9es--,! repeat+ patt]n 9 dra9age networks--,! divid+ l9es ( ! relief patt]ns3 l9eam5ts--,! composite repeat+ patt]ns ( ! high] ord]s--,read+ ref]5ces #bbc ,,*apt] ,,xviii ,,! ,,=ms ,,c>v$ ,,& ,,mold$ ,,by ,,waves ,! motion ( a wat] wave--,free waves & break]s--,effect ( ! break+ wave ^u a /eep1 rocky %ore3 ! not*$ cliff--,coves1 sea ar*es1 & /acks--,! cut rock t]race--,! cut & built t]race on a /eep %ore ( loose mat]ials--,! "w ( ! %ore curr5t--,! s& bea*--,! %+le bea*--,b>1 spit1 & b>ri]--,! l&-ti$ isl&--,a b>ri] s]ies--,"* pr(iles--,read+ ref]5ces #bca ,,*apt] ,,xix ,,coa/ ,,records ,,( ,,! ,,rise ,,or ,,fall ,,( ,,! ,,l& ,! *>act]s 9 :i* ! record has be5 pres]v$--,ev5 coa/ l9e ! m>k ( uplift--,a ragg$ coa/ l9e ! m>k ( subsid5ce--,sl[ uplift ( ! coa/s2 ! coa/al pla9 & cue/a--,! sudd5 uplifts ( ! coa/--,! uprais$ cliff--,! uplift$ b>ri] bea*--,coa/ t]races--,! sunk or embay$ coa/--,subm]g$ riv] *annels--,records ( an oscillation ( movem5t--,simultane\s contr>y movem5ts ^u a coa/--,! contra/$ isl&s ( ,san ,clem5te & ,santa ,catal9a--,! ,blue ,grotto ( ,capri--,"* pr(iles--,read+ ref]5ces #bde ,,*apt] ,,xx ,,! ,,glaci]s ,,( ,,m\nta9 ,,& ,,cont95t ,conditions ess5tial to glaciation--,! sn[-l9e--,importance ( m\nta9 b>ri]s 9 initiat+ glaci]s--,s5sitiv5ess ( glaci]s to temp]ature *anges--,! cycle ( glaciation--,! advanc+ hemicycle--,cont95tal & m\nta9 glaci]s contra/$--,! n\ri%m5t ( glaci]s--,! upp] & l[] cl\d zones ( ! atmosph]e #bfa ,,*apt] ,,xxi ,,! ,,cont95tal ,,glaci]s ,,( ,,pol> ,,regions ,! inl& ice ( ,gre5l&--,! m\nta9 ramp>t & its portals--,! m>g9al rock isl&s--,rock fragm5ts :i* travel ) ! ice--,! gr9d+ mill b5ea? ! ice--,! lift+ ( ! gr9d+ tools & _! incorporation )9 ! ice--,melt+ ^u ! glaci] m>g9s 9 ,gre5l&--,! m>g9al mora9es--,! outwa% pla9 or apron--,! cont95tal glaci] ( ,ant>ctica--,n\ri%m5t ( cont95tal glaci]s--,! glaci] broom--,field & pack ice--,! drift ( ! pack--,! ,ant>ctic %elf ice--,iceb]gs & sn[b]gs & ! mann] ( _! bir?--,read+ ref]5ces #bga ,,*apt] ,,xxii ,,! ,,cont95tal ,,glaci]s ,,( ,,! 8,,ice ,,age0 ,e>li] cycles ( glaciation--,contra/ ( ! glaciat$ & nonglaciat$ regions--,! 8driftless area0--,*>act]i/ics ( ! glaciat$ regions--,! glaci] grav+s--,y\ng] records ov] old]3 ! glaci] palimpse/--,! disp]sion ( ! drift--,! diamonds ( ! drift--,tabulat$ comp>ison ( ! glaciat$ & nonglaciat$ regions--,unassort$ & assort$ drift--,features into :i* ! drift is mold$--,m>g9al or 8kettle0 mora9es--,outwa% pla9s--,pitt$ pla9s & int]lobate mora9es--,esk]s--,druml9s--,! %elf ice ( ! ice age--,"* pr(iles #big ,,*apt] ,,xxiii ,,glacial ,,lakes ,,:i* ,,m>k$ ,,! ,,decl9e ,,( ,,! ,,la/ ,,ice ,,age ,int]f]5ce ( glaci]s ) dra9age--,tempor>y lakes due to ice block+--,! 8p>allel roads0 ( ! ,scotti% gl5s--,! glacial ,lake ,agassiz--,episodes ( ! glacial lake hi/ory )9 ! ,/4 ,lawr5ce ,valley--,! cresc5tic lakes ( ! e>li] /ages--,! e>ly ,lake ,maumee--,! lat] ,lake ,maumee--,lakes ,arkona & ,:ittlesey--,lake ,w>r5--,lakes ,iroquois & ,algonqu9--,! ,nipiss+ ,great ,lakes--,summ>y ( lake /ages--,p]man5t *anges ( dra9age effect$ by ! glaci]--,glacial ,lake ,ojibway 9 ! ,hudson's ,bay dra9age bas9--,read+ ref]5ces #cbj ,,*apt] ,,xxiv ,,! ,,uptilt ,,( ,,! ,,l& ,,at ,,! ,,close ,,( ,,! ,,ice ,,age ,! response ( ! e>?'s %ell to its ice mantle--,! ab&on$ /r&s z !y appe> to-day--,! records ( uplift ab\t ,mack9ac ,isl&--,! pres5t incl9ations ( ! uplift$ /r&s--,! h+e l9es ( uptilt--,future consequ5ces ( ! cont9u$ uptilt )9 ! lake region--,gilb]t's prophecy ( a future outlet ( ! ,great ,lakes to ! ,mississippi--,geological evid5ces ( cont9u$ uplift--,dr[n+ ( s\?we/]n %ores ( ,lakes ,sup]ior & ,erie--,read+ ref]5ces #cdj ,,*apt] ,,xxv ,,niag>a ,,falls ,a ,,clock ,,( ,,rec5t ,,geological ,,"t ,features 9 & ab\t ! ,niag>a gorge--,! drill+ ( ! gorge--,! pres5t rate ( recession--,future ext9ction ( ! ,am]ican ,fall--,! captur$ ,canadian ,fall at ,w9t]gre5 ,flats--,! ,:irlpool ,bas9 excavat$ f ! ,/4 ,david's gorge--,! %ap+ ( ! ,lewi/on ,esc>pm5t--,episodes ( ,niag>a's hi/ory & _! correlation ) ^? ( ! glacial lakes--,"t measures ( ! ,niag>a clock--,! horologe ( late glacial "t 9 ,sc&9avia--,read+ ref]5ces #ceb ,,*apt] ,,xxvi ,,l& ,,sculpture ,,by ,,m\nta9 ,,glaci]s ,contra/$ sculptur+ ( cont95tal & m\nta9 glaci]s--,w9d di/ribution ( ! sn[ :i* falls 9 m\nta9s--,! ni*es :i* =m on sn[drift sites--,! augm5t$ sn[drift moves d[n ! valley3 bir? ( ! glaci]--,! excavation ( ! glacial amphi!at] or cirque--,life hi/ory ( ! cirque--,groov$ & frett$ upl&s--,! features c>v$ above ! glaci]--,! features %ap$ b5ea? ! glaci]--,! cascade /airway 9 glaci]-c>v$ valleys--,! "* pr(iles :i* result f sculpture by m\nta9 glaci]s--,! sculpture accompli%$ by ice caps--,! ,norwegian t9d or beehive m\nta9--,read+ ref]5ces #cfg ,,*apt] ,,xxvii ,,successive ,,glaci] ,,types ,,( ,a ,,wan+ ,,glaciation ,transition f ! ice cap to ! m\nta9 glaci]--,! pi$mont glaci]--,! exp&$-foot glaci]--,! d5dritic glaci]--,! radiat+ glaci]--,! horse%oe glaci]--,! inh]it$-bas9 glaci]--,summ>y ( types ( m\nta9 glaci]--,read+ ref]5ces #chc ,,*apt] ,,xxviii ,,! ,,glaci]',s ,,surface ,,features ,,& ,,! ,,deposits ,,^u ,,its ,,b$ ,! glaci] fl[--,crevasses & sracs--,bodies giv5 up by ! ,glaci] des ,bossons--,! mora9es--,selective melt+ ^u ! glaci] surface--,glaci] dra9age--,deposits )9 ! vacat$ valley--,m>ks ( ! e>li] occupation ( m\nta9s by glaci]s--,read+ ref]5ces #cij ,,*apt] ,,xxix ,a ,,/udy ,,( ,,lake ,,bas9s ,fre% wat] & sal9e lakes--,newl& lakes--,bas9-range lakes--,rift-valley lakes--,e>?quake lakes--,crat] lakes--,c\le lakes--,mora9al lakes--,pit lakes--,gl9t or colk lakes--,ice-dam lakes--,glaci]-lobe lakes--,rock-bas9 lakes--,valley mora9e lakes--,l&slide lakes--,bord] lakes--,ox-b[ lakes--,sauc] lakes--,cresc5tic levee lakes--,raft lakes--,side-delta lakes--,delta lakes--,b>ri] lakes--,dune lakes--,s9k lakes--,k>/ lakes3 polj5--,playa lakes--,sal9es--,alluvial-dam lakes--,rsum--,read+ ref]5ces #dja ,,*apt] ,,xxx ,,! ,,ephem]al ,,exi/5ce ,,( ,,lakes ,lakes z settl+ bas9s--,draw+ (f ( wat] by erosion ( outlet--,! pull+ 9 ( headl&s & ! cutt+ (f ( bays--,lake ext9ction by peat gr[?--,ext9ction ( lakes 9 des]t regions--,! rle ( lakes 9 ! economy ( nature--,ice ramp>ts on lake %ores--,read+ ref]5ces #dbf ,,*apt] ,,xxxi ,,! ,,orig9 ,,& ,,! ,,=ms ,,( ,,m\nta9s ,a m\nta9 def9$--,! fe/oons ( m\nta9 arcs--,!ories ( orig9 ( ! m\nta9 arcs--,! ,atlantic & ,pacific coa/s contra/$--,! block type ( m\nta9--,m\nta9s ( outfl[ or upheap--,dom$ m\nta9s ( uplift2 laccolites--,m\nta9s c>v$ f plateaus--,! climatic conditions ( ! m\nta9 sculpture--,! effect ( ! resi/ant /ratum--,! m>k ( ! rift 9 ! erod$ m\nta9s--,read+ ref]5ces #dce ,,app5dices ,a4 ,! quick det]m9ation ( ! common m9]als #ddi ,b4 ,%ort descriptions ( "s common rocks #dfb ,c4 ,! prep>ation ( topographical maps #dfg ,d4 ,laboratory models = /udy 9 ! int]pretation ( geological maps #dgb ,e4 ,sugge/$ it9]>ies = pilgrimages to /udy e>? features #dge ,,index #dhi ,,li/ ,,( ,,plates ,,plate #a4 ,m\nt ,balf\r & ! ,balf\r ,glaci] 9 ! ,selkirks ,frontispiece ,,fac+ ,,page #b4 ,a4 ,lay]s compress$ 9 exp]im5ts & %[+ ! effect ( a compet5t lay] 9 ! process ( fold+ #dd ,b4 ,exp]im5tal production ( a s]ies ( p>allel ?ru/s )9 closely fold$ /rata #dd ,c4 ,app>atus to illu/rate %e>+ action )9 ! ov]turn$ limb ( a fold #dd #c4 ,a4 ,an e>?quake fault op5$ 9 ,=mosa 9 #aijf ) v]tical & lat]al displacem5ts comb9$ #gb ,b4 ,e>?quake faults op5$ 9 ,alaska 9 #ahhi on :i* v]tical slices ( ! e>?'s %ell h und]gone individual adju/m5ts #gb #d4 ,a4 ,exp]im5tal tank to illu/rate ! e>? movem5ts :i* are manife/$ 9 e>?quakes4 ,! sections ( ! e>?'s %ell are "h repres5t$ be=e adju/m5t has tak5 place #hb ,b4 ,! same app>atus aft] a sudd5 adju/m5t #hb ,c4 ,model to illu/rate a block displacem5t 9 rocks :i* are int]sect$ by ma/] jo9ts #hb #e4 ,a4 ,once wood$ region 9 ,*9a n[ r$uc$ to des]t ?r\gh de=e/ation #aef ,b4 8,bad ,l&s0 9 ! ,colorado ,des]t #aef #f4 ,a4 ,b>r5 ,k>/ l&scape ne> ! fam\s ,adelsb]g grottoes #ahh ,b4 ,surface ( a lime/one l$ge :]e jo9ts h be5 wid5$ ?r\gh solution #ahh #g4 ,a4 ,ranges ( dunes ^u ! m>g9 ( ! ,colorado ,des]t #baj ,b4 ,s& dunes encroa*+ ^u ! oasis ( ,ou$ ,s\f1 ,alg]ia #baj #h4 ,a4 ,! granite ne$les ( ,h>ney ,peak 9 ! ,black ,hills ( ,s\? ,dakota #baf ,b4 ,ca/ellat$ erosion *imneys 9 ,el ,cobra ,caon1 ,new ,mexico #baf #i4 ,map ( ! ,high ,pla9s at ! ea/]n front ( ! ,rocky ,m\nta9s #bbj #aj4 ,a4 ,view 9 ,spitzb]g5 to illu/rate ! dis9tegration ( rock "u ! control ( jo9ts #bbh ,b4 ,composite patt]n ( ! jo9t /ructures )9 rec5t alluvial deposits ( ! ,syrian ,des]t #bbh #aa4 ,a4 ,ripple m>k+s )9 an anci5t s&/one #bcb ,b4 ,wave break+ z x approa*es ! %ore #bcb #ab4 ,a4 ,v-%ap$ caon cut 9 an upl& rec5tly elevat$ f ! sea1 ,san ,clem5te ,isl&1 ,cali=nia #bef ,b4 ,a 8hogback0 at ! base ( ! ,bighorn ,m\nta9s1 ,wyom+ #bef #ac4 ,a4 ,precipit\s front ( ! ,bryant ,glaci] outlet ( ! ,gre5l& inl& ice #bgb ,b4 ,lat]al /ream beside ! ,b5$ict ,glaci] outlet1 ,gre5l& #bgb #ad4 ,view ( ! m>g9 ( ! ,ant>ctic cont95tal glaci] 9 ,kais] ,wilhelm ,l& #bhb #ae4 ,a4 ,an ,ant>ctic ice foot ) boat p>ty l&+ #bij ,b4 ,a ne> view ( ! front ( ! ,great ,ross ,b>ri]1 ,ant>ctica #bij #af4 ,a4 ,incis$ topography )9 ! 8driftless area0 #cjj ,b4 ,built-up topography )9 ! glaciat$ region #cjj #ag4 ,a4 ,sol$ glacial b[ld]s :i* %[ diff]5tly direct$ /ri ^u ! same facet #cjf ,b4 ,p]*$ b[ld] ^u a /riat$ l$ge ( diff]5t rock type1 ,bronx ,p>k1 ,new ,york #cjf ,c4 ,*>act]i/ic knob & bas9 surface ( a mora9e #cjf #ah4 ,a4 ,frett$ upl& ( ! ,alps se5 f ! summit ( ,m\nt ,blanc #cgb ,b4 ,model ( ! ,malasp9a ,glaci] & ! frett$ upl& above x #cgb #ai4 ,a4 ,cont\r map ( a groov$ upl&1 ,bighorn ,m\nta9s1 ,wyom+ #cgb ,b4 ,cont\r map ( a frett$ upl&1 ,philipsburg ,quadrangle1 ,montana #cgb #bj4 ,map ( ! surface model$ by m\nta9 glaci]s 9 ! ,si]ra ,nevadas ( ,cali=nia #cgf #ba4 ,a4 ,view ( ! ,h>v>d ,glaci]1 ,alaska1 %[+ ! *>act]i/ic t]races #cid ,b4 ,! t]m9al mora9e at ! foot ( a m\nta9 glaci] #cid #bb4 ,a4 ,model ( ! vic9ity ( ,*icago1 %[+ ! position ( ! outlet ( ! =m] ,lake ,*icago #djj ,b4 ,map ( ,yosemite ,falls & its e>li] site ne> ,eagle ,peak #djj #bc4 ,a4 ,view ( ! ,am]ican ,fall at ,niag>a1 %[+ ! accumulation ( blocks b5ea? #dad ,b4 ,cry/al ,lake1 a l&slide lake 9 ,colorado #dad #bd4 ,a4 ,app>atus = ex]cise 9 ! prep>ation ( topographic maps #dfh ,b4 ,! same app>atus 9 use = te/+ ! cont\rs ( a map #dfh ,c4 ,model+ app>atus 9 use #dfh ,,illu/rations ,,9 ,,! ,,text ,,fig4 ,,page #a4 ,diagram to %[ ! measure ( ! e>?'s surface irregul>ities #aa #b4 ,map to %[ ! reciprocal relation ( areas ( l& & sea #aa #c4 ,! tetrah$ral =m t[>d :i* ! e>? is t5d+ #ab #d4 ,a truncat$ tetrah$ron to %[ ! reciprocal relation ( projection & depression ^u ! surface #ac #e4 ,approximations to e>li] & pres5t figures ( ! e>? #ae #f4 ,diagrams = comp>ison ( coa/s ^u an upright & ^u an inv]t$ tetrah$ron #ag #g4 ,! cont95ts1 includ+ subm]g$ portions #ah #h4 ,diagram to indicate ! altitude ( diff]5t p>ts ( ! li?osph]e surface #ah #i4 ,diagram to %[ h[ ! t]re/rial rocks grade into ! meteorites #bb #aj4 ,comp>ison ( a cry/all9e ) an amorph\s sub/ance #bd #aa4 8,light figure0 se5 ^u et*$ surface ( calcite #be #ab4 ,batt]$ s& gra9s :i* h develop$ cry/al faces #bf #ac4 ,unassimilat$ gra9s ( qu>tz )9 a g>net cry/al #bh #ad4 ,new m9]als develop$ ab\t ! core ( an augite cry/al #bh #ae4 ,a common rim ( new m9]al develop$ by reaction :]e e>li] m9]als come into contact #bh #af4 ,lam9at$ /ructure ( a s$im5t>y rock #cj #ag4 ,*>act]i/ic textures ( igne\s rocks #cc #ah4 ,diagram to %[ ! ord] ( s$im5ts laid d[n dur+ a transgression ( ! sea #cg #ai4 ,fractures produc$ by compression ( a block ( mold]'s wax #da #bj4 ,app>atus to illu/rate ! fold+ ( /rata #da #ba4 ,diagrams ( fold types #db #bb4 ,diagrams to illu/rate cru/al %ort5+ #db #bc4 ,anticl9al & syncl9al folds #dc #bd4 ,diagrams to illu/rate ! %apes ( rock folds #dd #be4 ,second>y & t]ti>y flexures sup]impos$ ^u ! prim>y ones #dd #bf4 ,a b5t /ratum to illu/rate t5sion & compression ^u opposite sides #de #bg4 ,a geological section ) truncat$ ar*es re/or$ #dg #bh4 ,diagram to illu/rate ! nature ( /rike & dip #dg #bi4 ,diagram to %[ ! use ( ,t symbols = /rike & dip obs]vation #dh #cj4 ,diagram to %[ h[ ! ?ickness ( a =mation is det]m9$ #di #ca4 ,a plung+ anticl9e #ej #cb4 ,a plung+ syncl9e #ej #cc4 ,an uncon=mity ^u ! coa/ ( ,cali=nia #ea #cd4 ,s]ies ( diagrams to illu/rate ! episodes involv$ 9 ! production ( an angul> uncon=mity #eb #ce4 ,types ( deceptive or erosional uncon=mities #ec #cf4 ,a set ( ma/] jo9ts 9 %ale #ee #cg4 ,diagram to %[ ! mann] ( replacem5t ( "o set ( jo9ts by ano!r #ef #ch4 ,diagram to %[ ! diff]5t comb9ations ( jo9t s]ies #ef #ci4 ,view ( ! %ore 9 ,we/ ,gre5l& #eg #dj4 ,view 9 ,icel& :i* %[s jo9t int]vals ( m ?an "o ord] #eg #da4 ,fault$ blocks ( basalt ne> ,woodbury1 ,connecticut #eh #db4 ,a fault 9 previ\sly di/urb$ /rata #ei #dc4 ,diagram to %[ ! effect ( erosion ^u a fault #fj #dd4 ,a fault plane exhibit+ drag #fj #de4 ,map to %[ h[ a fault may be indicat$ by abrupt *anges 9 /rike & dip #fa #df4 ,a s]ies ( p>allel faults reveal$ by (fsets #fa #dg4 ,field map prep>$ f ! laboratory table #fd #dh4 ,areal geological map bas$ ^u ! field map #fd #di4 ,a portion ( ! ru9s ( ,mess9a #fg #ej4 ,ru9s ( ! ,c>negie ,palace ( ,peace at ,c>taga1 ,co/a ,rica #fh #ea4 ,ov]turn$ b[ld]s f ,assam e>?quake ( #ahig #fi #eb4 ,po/ sunk into gr\nd dur+ ,*>le/on e>?quake #fi #ec4 ,map %[+ localities :]e %ocks h be5 report$ at sea (f ,cape ,m5doc9o1 ,cali=nia #gj #ed4 ,effect ( seismic wat] wave 9 ,japan #gj #ee4 ,a fault ( v]tical displacem5t #ga #ef4 ,esc>pm5t produc$ by an e>?quake fault 9 ,india #gb #eg4 ,a fault ( lat]al displacem5t #gb #eh4 ,f5ce p>t$ & displac$ by lat]al displacem5t on fault dur+ ,cali=nia e>?quake #gb #ei4 ,fault ) v]tical & lat]al displacem5ts comb9$ #gb #fj4 ,diagram to %[ h[ small faults may be mask$ at ! e>?'s surface #gc #fa4 8,mole hill0 effect above buri$ e>?quake fault #gc #fb4 ,po/-glacial e>?quake faults #gd #fc4 ,e>?quake cracks 9 ,colorado des]t #gd #fd4 ,railway tracks brok5 or buckl$ at "t ( e>?quake #ge #fe4 ,railroad bridge 9 ,japan damag$ by e>?quake #ge #ff4 ,diagrams to %[ contraction ( e>?'s cru/ dur+ an e>?quake #gf #fg4 ,map ( ! ,*$rang fault ( ,india #gf #fh4 ,displacem5ts along e>?quake fault 9 ,alaska #gg #fi4 ,abrupt *ange 9 direction ( ?r[ ^u an e>?quake fault #gg #gj4 ,map ( faults 9 ! ,ow5s ,valley1 ,cali=nia1 =m$ dur+ e>?quake ( #ahgb #gh #ga4 ,m>quetry ( ! rock floor 9 ! ,tonopah di/rict1 ,nevada #gi #gb4 ,map ( ,alaskan coa/ to %[ adju/m5ts ( level dur+ an e>?quake #gi #gc4 ,an ,alaskan %ore elevat$ sev5te5 feet dur+ ! e>?quake ( #ahii #hj #gd4 ,p>tially subm]g$ =e/ f depression ( %ore 9 ,alaska dur+ e>?quake #hj #ge4 ,effect ( settlem5t ( ! %ore at ,port ,royal dur+ e>?quake ( #aijg #hj #gf4 ,diagrams to illu/rate ! dra9+ ( lakes dur+ e>?quakes #hc #gg4 ,diagram to illu/rate ! d]angem5ts ( wat] fl[ dur+ an e>?quake #hd #gh4 ,mud cones align$ ^u an e>?quake fissure 9 ,s]via #hd #gi4 ,crat]let =m$ ne> ,*>le/on1 ,s\? ,c>ol9a1 dur+ ! e>?quake ( #ahhf #he #hj4 ,cross section ( a crat]let #he #ha4 ,map ( ! isl& ( ,is*ia to %[ ! conc5tration ( e>?quake %ocks #hg #hb4 ,a l9e ( e>? fracture reveal$ 9 ! plan ( ! relief #hg #hc4 ,seismotectonic l9es ( ! ,we/ ,indies #hh #hd4 ,device to illu/rate ! diff]5t effects ( e>?quakes 9 firm rock & 9 loose mat]ials #hh #he4 ,h\se wreck$ 9 ,san ,francisco e>?quake #ij #hf4 ,build+ wreck$ 9 ,cali=nia e>?quake by ro( & upp] floor batt]+ d[n ! upp] walls #ia #hg4 ,brea*$ volcanic cone 9 ,new ,zeal& %[+ ! b5d+ d[n ( ! /rata ne> ! v5t #if #hh4 ,view ( ! new ,camigu9 volcano =m$ 9 #ahga 9 ! ,philipp9es #ig #hi4 ,map to %[ ! belts ( active volcanoes #ih #ij4 ,a portion ( ! 8fire girdle0 ( ! ,pacific #ih #ia4 ,volcanic cones =m$ 9 #aghc above ! ,skaptr fissure 9 ,icel& #ii #ib4 ,diagrams to illu/rate ! location ( volcanic v5ts ^u fissure l9es #ajj #ic4 ,outl9e map %[+ ! arrangem5t ( volcanic v5ts ^u ! isl& ( ,java #ajj #id4 ,map %[+ ! migration ( volcanoes along a fissure #aja #ie4 ,basaltic plateau ( ! nor?we/]n ,unit$ ,/ates due to fissure eruptions ( lava #ajb #if4 ,lava pla9s ab\t ! ,snake ,riv] 9 ,idaho #ajb #ig4 ,*>act]i/ic pr(iles ( lava volcanoes #ajc #ih4 ,a driblet cone #ajd #ii4 ,leff+well ,crat]1 a c9d] cone 9 ! ,ow5s ,valley1 ,cali=nia #ajd #ajj4 ,map ( ,hawaii & its lava volcanoes #ajf #aja4 ,section ?r\gh ,mauna ,loa & ,kilauea #ajf #ajb4 ,s*ematic diagram to illu/rate ! mov+ plat=m 9 ! crat] ( ,kilauea #ajg #ajc4 ,view ( ! op5 lava lake ( ,halemaumau #ajh #ajd4 ,map to %[ ! mann] ( outfl[ ( ! lava f ,kilauea 9 ! eruption ( #ahdj #aji #aje4 ,lava ( ,matavanu fl[+ d[n to ! sea dur+ ! eruption ( #aijf #aaj #ajf4 ,lava /ream dis*>g+ into ! sea f a lava tunnel #aaa #ajg4 ,diagrammatic repres5tation ( ! /ructure ( lava volcanoes z a result ( ! dra9+ ( froz5 lava /reams #aab #ajh4 ,diagram to %[ ! =mation ( mesas by outfl[ ( lava 9 valleys & subsequ5t erosion #aab #aji4 ,surface ( lava ( ! ,pahoehoe type #aac #aaj4 ,?ree successive views to %[ ! gr[? ( ! isl& ( ,savaii1 f lava outfl[ 9 #aijf #aac #aaa4 ,view ( ! volcano ( ,/romboli %[+ ! exc5tric position ( ! crat] #aaf #aab4 ,diagrams to illu/rate ! eruptions )9 ! crat] ( ,/romboli #aag #aac4 ,map ( ,volcano 9 ! olian ,isl&s #aah #aad4 8,bread-cru/0 lava projectile f ! eruption ( ,volcano 9 #ahhh #aai #aae4 8,caulifl[] cl\d0 ( /eam & a% ris+ above ! c9d] cone ( ,volcano #abj #aaf4 ,eruption ( ,taal volcano 9 #aiaa se5 f a di/ance ( six miles #abj #aag4 ,! ?ick mud v5e] ^u ! isl& ( ,taal 7aft] a photograph by ,d5i/on7 #aba #aah4 ,a pe>-%ap$ lava projectile #aba #aai4 ,artificial production ( a c9d] cone #abb #abj4 ,diagram to %[ ! contra/ betwe5 a lava dome & a c9d] cone #abc #aba4 ,mayon volcano on ! isl& ( ,luzon1 ,philipp9e ,isl&s #abc #abb4 ,a s]ies ( brea*$ c9d] cones due to migration ( ! eruption along a fissure #abd #abc4 ,! m\? ^u ! inn] cone ( ,m\nt ,vesuvius f :i* fl[$ ! lava ( #ahgb #abd #abd4 ,a r[ ( p>asitic cones rais$ above a fissure op5$ on ! flanks ( ,etna 9 #ahib #abe #abe4 ,view ( ,etna1 %[+ ! p>asitic cones ^u its flanks #abe #abf4 ,sket* map ( ,etna to %[ ! areas cov]$ by lava & tuff respectively #abf #abg4 ,panum crat] %[+ ! cald]a #abf #abh4 ,view ( ,m\nt ,vesuvius be=e ! eruption ( #aijf #abg #abi4 ,sket*es ( ! summit ( ! ,vesuvian cone to br+ out ! *anges 9 its outl9e #abh #acj4 ,night view ( ,vesuvius f ,naples be=e ! outbreak ( #aijf1 %[+ a small lava /ream desc5d+ ! c5tral cone #abi #aca4 ,scoriace\s lava encroa*+ ^u ! tracks ( ! ,vesuvian railway #acj #acb4 ,map ( ,vesuvius1 %[+ ! position ( ! lava m\?s op5$ ^u its flanks dur+ ! eruption ( #aijf #aca #acc4 ,! a% curta9 ov] ,vesuvius lift+ & disclos+ ! outl9es ( ! m\nta9 #acb #acd4 ,! c5tral cone ( ,vesuvius z x appe>$ aft] ! eruption ( #aijf #acb #ace4 ,a sunk5 road ^u ,vesuvius fill$ ) indrift$ a% #acc #acf4 ,view ( ,vesuvius f ! s\?we/ dur+ ! wan+ /ages ( ! eruption #acc #acg4 ,! ma9 lava /ream advanc+ ^u ,boscotrecase #acc #ach4 ,a p9e snapp$ (f by ! lava & c>ri$ =w>d ^u its surface #acc #aci4 ,lava front pu%+ ov] & runn+ ar\nd a wall 9 its pa? #acd #adj4 ,"o ( ! ru9$ villas 9 ,boscotrecase #acd #ada4 ,?ree diagrams to illu/rate ! sequ5ce ( ev5ts dur+ ! cone-build+ & crat]-produc+ p]iods #ace #adb4 ,! sp9e ( ,pel ris+ above ! *imney ( ! volcano aft] ! eruption ( #aijb #acf #adc4 ,successive outl9es ( ! ,pel sp9e #acg #add4 ,corrugat$ surface ( ! ,vesuvian cone due to ! mud fl[s :i* foll[$ ! eruption ( #aijf #ach #ade4 ,view ( ! ,kamm]bhl ne> ,eg] 9 ,bohemia #aci #adf4 ,volcanic plug expos$ by natural dissection ( a volcanic cone 9 ,colorado #adj #adg4 ,a dike cutt+ b$s ( tuff 9 a p>tly dissect$ volcano ( s\?we/]n ,colorado #adj #adh4 ,map & g5]al view ( ,/4 ,paul's rocks1 a volcanic cone dissect$ by waves #ada #adi4 ,dissection by explosion ( ,little ,b&ai-san 9 #ahhh #ada #aej4 ,! half-subm]g$ volcano ( ,krakatoa be=e & aft] ! eruption ( #ahhc #adb #aea4 ,! cicatrice ( ! ,banat #adb #aeb4 ,diagram to illu/rate a probable cause ( =mation ( lava res]voirs & ! connection ) volcanoes ^u ! surface #adc #aec4 ,effect ( relief ( load ^u rocks by ar*+ ( a compet5t =mation #add #aed4 ,"* pr(iles connect$ ) volcanoes #adf #aee4 ,diagrams to %[ ! effect ( decomposition 9 produc+ sph]oidal b[ld]s #aej #aef4 ,sph]oidal wea!r+ ( an igne\s rock #aea #aeg4 ,dome /ructure 9 granite mass #aeb #aeh4 ,talus slope b5ea? a cliff #aec #aei4 ,/rip$ gr\nd f soil fl[ #aed #afj4 ,pavem5t ( horizontal surface due to soil fl[ #aed #afa4 ,tree roots pry+ rock ap>t on fissure #aed #afb4 ,b[ld] split by a gr[+ tree #aee #afc4 ,rock mantle b5ea? soil & vegetable mat #aee #afd4 ,diagram to %[ ! v>y+ ?ickness ( mantle rock ^u ! diff]5t portions ( a hill surface #aef #afe4 ,gullies f e>lie/ /age ( a riv]'s life #afj #aff4 ,p>tially dissect$ upl& #afj #afg4 ,longitud9al sections ( upp] portion ( a riv] valley #afa #afh4 ,map & sections ( a /ream me&] #afc #afi4 ,tree und]m9$ on ! out] bank ( a me&] #afd #agj4 ,diagrams to %[ ! successive positions ( /ream me&]s #afd #aga4 ,an ox-b[ lake 9 ! flood pla9 ( a riv] #afe #agb4 ,s*ematic repres5tation ( a s]ies ( riv] t]races #afe #agc4 8,bird-foot0 delta ( ! ,mississippi ,riv] #afg #agd4 ,diagrams to %[ ! nature ( delta deposits z exhibit$ 9 sections #afh #age4 ,gorge ( ! ,riv] ,rh9e ne> ,/4 ,go>s #afi #agf4 ,valley ) r\nd$ %\ld]s *>act]i/ic ( ! /age ( adolesc5ce #agj #agg4 ,view ( a maturely dissect$ upl& #agj #agh4 ,hog>?'s l9e ( beauty #aga #agi4 ,view ( ! oldl& ( ,new ,engl&1 ) ,m\nt ,monadnock ris+ 9 ! di/ance #aga #ahj4 ,comp>ison ( ! cross sections ( riv] valleys ( diff]5t /ages #agb #aha4 ,! ,beav]tail ,b5d ( ! ,yakima ,riv] #agc #ahb4 ,a rejuv5at$ riv] valley #agd #ahc4 ,plan ( a riv] n>r[s #agd #ahd4 ,successive diagrams to illu/rate ! orig9 ( 8trellis dra9age0 #age #ahe4 ,sket* maps to %[ ! e>li] & pres5t dra9age ne> ,h>p]'s ,f]ry #agf #ahf4 ,section to illu/rate ! hi/ory ( ,snick]s ,gap #agg #ahg4 ,"* pr(iles ( l&scapes %ap$ by /ream erosion 9 humid climates #agg #ahh4 ,diagram to %[ ! seasonal range 9 ! position ( ! wat] table #ahj #ahi4 ,diagram to %[ ! effect ( an imp]vi\s lay] ^u ! desc5d+ wat] #aha #aij4 ,sket* map to illu/rate corrosion ( lime/one along two s]ies ( v]tical jo9ts #aha #aia4 ,diagram to %[ ! relation ( lime/one cav]ns to ! riv] sy/em ( ! di/rict #ahb #aib4 ,plan ( a portion ( ,mammo? ,cave1 ,k5tucky #ahc #aic4 ,trees & %rubs gr[+ ^u ! bottoms ( lime/one s9ks #ahc #aid4 ,diagrams to %[ ! mann] ( =mation ( /alactites & /alagmites #ahe #aie4 ,s9t] =mations 9 ! ,luray cav]ns #ahf #aif4 ,map ( ! dol9es ( ! ,k>/ region #ahg #aig4 ,cross section ( a dol9e =m$ by inbreak #ahg #aih4 ,%>p ,k>r5 ( ! ,if5platte #ahh #aii4 ,! ,zirknitz seasonal lake #ahi #bjj4 ,fissure spr+s arrang$ at int]sections ( rock fractures #aij #bja4 ,s*ematic diagrams to illu/rate ! diff]5t types ( artesian wells #aia #bjb4 ,cross section ( ,geysir1 ,icel& #aib #bjc4 ,app>atus = simulat+ geys] action #aic #bjd4 ,cone ( silice\s s9t] ab\t ! ,lone ,/> ,geys] #aid #bje4 ,=m] %ore l9es 9 ! ,great ,bas9 #aih #bjf4 ,map ( ! =m] ,lake ,bonneville #aii #bjg4 ,borax deposits 9 ,dea? ,valley1 ,cali=nia #bja #bjh4 ,holl[$ =ms ( wea!r$ granite 9 a des]t ( ,c5tral ,asia #bja #bji4 ,holl[ hewn blocks 9 a wall 9 ! ,wadi ,gu]raui #bjb #baj4 ,smoo? granite domes %ap$ by exfoliation #bjc #baa4 ,granite blocks r5t by diffission #bjd #bab4 8,mu%room ,rock0 f a des]t 9 ,wyom+ #bje #bac4 ,w9dkant5 %ap$ by s& bla/ 9 ! des]t #bje #bad4 ,! 8/one lattice0 ( ! des]t #bjf #bae4 ,%ad[ erosion 9 ! des]t #bjf #baf4 ,cliffs 9 loess ) *>act]i/ic v]tical jo9t+ #bjg #bag4 ,a caon 9 loess worn by traffic & w9d #bjg #bah4 ,diagrams to illu/rate ! effects ( ob/ructions 9 arre/+ w9d-driv5 s& #bji #bai4 ,s& accumulat+ on ei!r side ( a firm & imp5etrable ob/ruction #baj #bbj4 ,successive diagrams to illu/rate ! hi/ory ( ! t[n ( ,kunz5 ^u ! ,kuris*e ,nehrung #baj #bba4 ,view ( des]t b>*ans #baa #bbb4 ,diagrams to %[ ! relation%ips ( dunes to s& supply & w9d direction #baa #bbc4 ,ideal section %[+ ! ris+ m\nta9 wall ab\t a des]t & ! neighbor+ slope #bab #bbd4 ,dry delta at ! foot ( a range ^u ! bord]s ( a des]t #bac #bbe4 ,map ( di/ribut>ies ( /reams :i* issue at ! we/]n base ( ! ,si]ra ,nevadas #bac #bbf4 ,a gr\p ( 8demoiselles0 9 ! 8bad l&s0 #bad #bbg4 ,amphi!at] at ! head ( ! ,wadi ,b5i ,sur #bae #bbh4 ,mesa & outli] 9 ! ,leucite ,hills ( ,wyom+ #baf #bbi4 ,flat-bottom$ bas9 sep>at+ dunes #baf #bcj4 ,bill[y surface ( ! salt cru/ on ! c5tral s9k ( ! des]t ( ,lop #bag #bca4 ,s*ematic diagram to %[ ! zones ( deposition 9 _! ord] f ! m>g9 to ! c5t] ( a des]t #bag #bcb4 ,m\nds ^u ! site ( ! buri$ city ( ,nippur #bah #bcc4 ,exhum$ /ructures 9 ! buri$ city ( ,nippur #bah #bcd4 ,section across ! ,high ,pla9s #bai #bce4 ,section across ! l5ticul> ?reads ( alluvial deposits ( ! ,high ,pla9s #bbj #bcf4 ,di/ribut>ies ( ! foot hills sup]impos$ ^u an e>li] s]ies #bbj #bcg4 ,"* pr(iles 9 ! l&scapes ( arid l&s #bbj #bch4 ,ra9 sculptur+ "u control by jo9ts #bbd #bci4 ,sagg+ ( lime/one above jo9ts #bbd #bdj4 ,map ( ! jo9t-controll$ ,abisko ,caon 9 ,nor!rn ,lapl& #bbe #bda4 ,map ( ! gorge ( ! ,zambesi ,riv] bel[ ,victoria ,falls #bbe #bdb4 ,controll$ dra9age network ( ! ,%epaug ,riv] 9 ,connecticut #bbf #bdc4 ,a riv] network ( repeat+ rectangul> patt]n #bbf #bdd4 ,squ>$ m\nta9 masses :i* reveal a di/ribution ( jo9ts 9 block patt]ns ( diff]5t ord]s #bbh #bde4 ,isl& gr\ps ( ! ,l(ot5 ,ar*ipelago #bbi #bdf4 ,diagrams to illu/rate ! composite pr(iles ( ! isl&s on ! ,norwegian coa/ #bbi #bdg4 ,diagram to %[ ! nature ( ! motions )9 a free wat] wave #bca #bdh4 ,diagram to illu/rate ! trans=mation ( a free wave into a break] #bcb #bdi4 ,not*$ rock cliff & fall5 blocks #bcc #bej4 ,a wave-cut *asm "u control by jo9ts #bcc #bea4 ,gr& ,ar* ^u "o ( ! ,apo/le ,isl&s 9 ,lake ,sup]ior #bcd #beb4 ,/ack ne> ! %ore ( ,lake ,sup]ior #bcd #bec4 ,! ,m>ble ,isl&s1 /acks 9 a lake ( ! s\!rn ,&es #bce #bed4 ,squ>$ /acks reveal+ ! position ( ! jo9t planes on :i* !y 7 c>v$ #bce #bee4 ,ideal section cut by waves ^u a /eep rocky %ore #bcf #bef4 ,map %[+ ! outl9es ( ! isl& ( ,heligol& at diff]5t /ages 9 its hi/ory #bcf #beg4 ,ideal section c>v$ by waves ^u a /eep %ore ( loose mat]ials #bcg #beh4 ,slop+ cliff & b\ld] pavem5t at ,scituate1 ,massa*usetts #bcg #bei4 ,map to %[ ! nature ( ! %ore curr5t & ! =ms :i* are mold$ by x #bch #bfj4 ,cresc5t-%ap$ bea* 9 ! lee ( a headl& #bci #bfa4 ,cross section ( a bea* pebble #bci #bfb4 ,a /orm bea* on ! nor!a/ %ore ( ,gre5 ,bay #bdj #bfc4 ,spit ( %+le on ,au ,tra9 ,isl&1 ,lake ,sup]ior #bdj #bfd4 ,b>ri] bea* 9 front ( a lagoon #bda #bfe4 ,cross section ( a b>ri] bea* ) lagoon 9 its re> #bdb #bff4 ,cross section ( a s]ies ( b>ri]s & an out] b> #bdb #bfg4 ,a b>ri] s]ies & an out] b> on ,lake ,m5dota at ,madison1 ,wiscons9 #bdb #bfh4 ,s]ies ( b>ri]s at ! we/]n end ( ,lake ,sup]ior #bdc #bfi4 ,"* pr(iles result+ f wave action ^u %ores #bdc #bgj4 ,! ev5 %ore l9e ( a rais$ coa/ #bdf #bga4 ,! ragg$ coa/ l9e produc$ by subsid5ce #bdf #bgb4 ,portion ( ! ,atlantic coa/al pla9 at ! base ( ! oldl& #bdf #bgc4 ,ideal =m ( cue/as & int]m$iate l[l&s c>v$ f a coa/al pla9 #bdg #bgd4 ,uplift$ sea cave on ! coa/ ( ,cali=nia #bdh #bge4 ,d\ble-not*$ cliff ne> ,cape ,tiro1 ,celebes #bdh #bgf4 ,uplift$ /acks on ! coa/ ( ,cali=nia #bdi #bgg4 ,uplift$ %+le bea* across ! entrance to a =m] bay ^u ! coa/ ( ,cali=nia #bej #bgh4 ,rais$ bea* t]races ne> ,elie1 ,fife1 ,scotl& #bej #bgi4 ,uplift$ sea cliffs & t]races on ! ,alaskan coa/ #bej #bhj4 ,diagrams to %[ h[ excessive s9k+ ^u ! sea floor w cause ! %ore to migrate l&w>d #bea #bha4 ,a dr[n$ riv] m\? or e/u>y ^u a coa/al pla9 #bea #bhb4 ,ar*ipelago ( /eep rocky islets due to subm]g5ce #beb #bhc4 ,! subm]g$ ,hudsonian *annel :i* cont9ues ! ,hudson ,riv] across ! cont95tal %elf #beb #bhd4 ,m>9e clay deposits ne> ! m\?s ( ! ,ma9e riv]s :i* pres]ve a record ( e>li] subsid5ce & lat] elevation #bec #bhe4 ,view ( ! ?ree /&+ columns ( ! ,temple ( ,jupit] ,s]apis1 at ,pozzuoli #bed #bhf4 ,?ree successive views to set =? ! rec5t oscillations ( level on ! nor!rn %ore ( ! ,bay ( ,naples #bee #bhg4 ,relief map ( ,san ,clem5te ,isl&1 ,cali=nia #bef #bhh4 ,relief map ( ,santa ,catal9a ,isl&1 ,cali=nia #beg #bhi4 ,cross section ( ! ,blue ,grotto1 on ! isl& ( ,capri #beh #bij4 ,"* pr(iles ( coa/ elevation & subsid5ce #bei #bia4 ,map %[+ ! di/ribution ( exi/+ glaci]s & ! two important w9d poles ( ! e>? #bfc #bib4 ,an ,alaskan glaci] spread+ out at ! foot ( ! range :i* n\ri%es x #bfd #bic4 ,surface ( a glaci] ^: upp] lay]s spread ) b slight re/ra9t f reta9+ walls #bfe #bid4 ,section ?r\gh a m\nta9 glaci] #bfg #bie4 ,pr(ile across ! l>ge/ ( ! ,icel&ic ice caps #bfg #bif4 ,ideal section across a cont95tal glaci] #bfg #big4 ,view ( ! ,eyriks ,jkull1 an ice cap ( ,icel& #bfh #bih4 ,! zones ( ! l[] atmosph]e z reveal$ by rec5t kite & balloon exploration #bfi #bii4 ,map ( ,gre5l&1 %[+ ! area ( inl& ice & ! r\tes ( explor]s #bga #cjj4 ,pr(ile 9 natural proportions across ! s\!rn end ( ! cont95tal glaci] ( ,gre5l& #bgb #cja4 ,map ( a glaci] tongue ) dimple above #bgc #cjb4 ,edge ( ! ,gre5l& inl& ice1 %[+ ! nunataks dim9i%+ 9 size t[>d ! int]ior #bgd #cjc4 ,moat surr\nd+ a nunatak 9 ,victoria ,l& #bgd #cjd4 ,a glaci] pavem5t ( ,p]mo-,c>bonif]\s age 9 ,s\? ,africa #bgf #cje4 ,diagrams to illu/rate ! mann] ( =mation ( scape colks #bgg #cjf4 ,m>g9al mora9e n[ =m+ at ! edge ( ! cont95tal glaci] ( ,gre5l& #bgi #cjg4 ,small lake betwe5 ! ice front & a mora9e :i* x has rec5tly built #bgi #cjh4 ,view ( a dra9$ lake bottom betwe5 ! ice front & an ab&on$ mora9e #bhj #cji4 ,diagrams to %[ ! mann] ( =mation & ! /ructure ( an outwa% pla9 & fosse #bhj #caj4 ,map ( ! ice masses ( ,victoria ,l&1 ,ant>ctica #bhb #caa4 ,sections across ! inl& ice & ! %elf ice ( ,ant>ctica #bhc #cab4 ,diagram to %[ ! nature ( ! fix$ glacial anticyclone above cont95tal glaci]s #bhd #cac4 ,sn[ deltas ab\t ! m>g9s ( a glaci] tongue 9 ,gre5l& #bhe #cad4 ,view ( ! sea ice ( ! ,arctic region #bhf #cae4 ,map ( ! nor? pol> regions1 %[+ ! area ( drift ice & ! tracks ( ! ,jeannette & ! ,fram #bhh #caf4 ,! %elf ice ( ,coats ,l& ) surr\nd+ pack ice #bij #cag4 ,tidewat] cliff on a glaci] tongue f :i* iceb]gs are born #bij #cah4 ,a ,gre5l&ic iceb]g aft] a long j\rney 9 w>m latitudes #bia #cai4 ,diagram %[+ "o way 9 :i* nor!rn iceb]gs are born f ! glaci] tongue #bia #cbj4 ,a nor!rn iceb]g surr\nd$ by sea ice #bib #cba4 ,tabul> ,ant>ctic iceb]g sep>at+ f ! %elf ice #bic #cbb4 ,map ( ! globe1 %[+ ! areas cov]$ by cont95tal glaci]s dur+ ! 8ice age0 #big #cbc4 ,glaciat$ granite b[ld] wea!r$ out ( a mora9e ( ,p]mo-,c>bonif]\s age1 ,s\? ,au/ralia #bih #cbd4 ,map to %[ ! glaciat$ & nonglaciat$ regions ( ,nor? ,am]ica #bih #cbe4 ,map ( ! glaciat$ & nonglaciat$ areas ( nor!rn ,europe #bii #cbf4 ,an un/able erosion remnant *>act]i/ic ( ! 8driftless area0 #cjj #cbg4 ,diagram %[+ ! mann] 9 :i* a cont95tal glaci] oblit]ates exi/+ valleys #cja #cbh4 ,lake & m>% di/rict 9 nor!rn ,wiscons9 #cjb #cbi4 ,cross section 9 natural proportion ( ! late/ ,nor? ,am]ican cont95tal glaci] #cjc #ccj4 ,diagram %[+ ! e>li] & ! lat] glaci] records toge!r ^u ! same lime/one surface #cjd #cca4 ,map to %[ ! outcropp+s ( peculi> rock types 9 ! region ( ! ,great ,lakes1 & "s localities :]e 8drift copp]0 has be5 collect$ #cje #ccb4 ,map ( ! 8b[ld] tra90 f ,iron ,hill1 ,rhode ,isl& #cjf #ccc4 ,%apes & approximate natural sizes ( "s ( ! diamonds f ! ,great ,lakes region #cjg #ccd4 ,glacial map ( a portion ( ! ,great ,lakes region #cjh #cce4 ,section 9 co>se till #caj #ccf4 ,sket* map ( portions ( ,mi*igan1 ,ohio1 & ,indiana1 %[+ ! di/ribution ( mora9es #cab #ccg4 ,map ( ! vic9ity ( ,devil's ,lake1 ,wiscons91 p>tly cov]$ by ! cont95tal glaci] #cac #cch4 ,mora9e ) outwa% apron 9 front #cac #cci4 ,fosse betwe5 an outwa% pla9 & a mora9e #cad #cdj4 ,view along an esk] 9 s\!rn ,ma9e #cae #cda4 ,outl9e map ( mora9es & esk]s 9 ,f9l& #cae #cdb4 ,sket* maps %[+ ! relation%ips ( druml9s & esk]s #caf #cdc4 ,view ( a druml91 %[+ an op5+ 9 ! till #cag #cdd4 ,outl9e map ( ! front ( ! ,gre5 ,bay lobe to %[ ! relation%ips ( druml9s1 mora9es1 outwa% pla9s1 & gr\nd mora9e #cag #cde4 ,"* pr(iles ref]able to cont95tal glaci] #cah #cdf4 ,view ( ! flood pla9 ( ! anci5t ,ill9ois ,riv] ne> ,peoria #cbj #cdg4 ,broadly t]rac$ valleys :i* m>k ! floods t once issu$ f ! cont95tal glaci] ( ,nor? ,am]ica #cba #cdh4 ,bord] dra9age ab\t ! retreat+ ice front s\? ( ,lake ,erie #cba #cdi4 ,! 8p>allel roads0 ( ,gl5 ,roy 9 ! ,scotti% ,highl&s #cbb #cej4 ,map ( ,gl5 ,roy & neighbor+ valleys ( ! ,scotti% ,highl&s #cbb #cea4 ,?ree successive diagrams to set =? ! late glacial lake hi/ory ( ! ,scotti% gl5s #cbd #ceb4 ,h>ve/+ "t on ! f]tile floor ( ! glacial ,lake ,agassiz #cbe #cec4 ,map ( ,lake ,agassiz #cbe #ced4 ,map %[+ "s ( ! bea*es ( ,lake ,agassiz & its outlet #cbf #cee4 ,n>r[s ( ! ,w>r5 ,riv] :]e x pass$ betwe5 jaws ( granite & gneiss #cbg #cef4 ,map ( ! valley ( ! ,w>r5 ,riv] ne> ,m9neapolis #cbg #ceg4 ,portion ( ! ,h]man bea* on ! %ore ( ! =m] ,lake ,agassiz #cbh #ceh4 ,map ( ! cont95tal glaci] ( ,nor? ,am]ica :5 x cov]$ ! entire ,/4 ,lawr5ce bas9 #cbi #cei4 ,outl9e map ( ! e>ly ,lake ,maumee #ccj #cfj4 ,map to %[ ! fir/ /ages ( ! ice-damm$ lakes )9 ! ,/4 ,lawr5ce bas9 #ccj #cfa4 ,outl9e map ( ! lat] ,lake ,maumee & its outlet #ccb #cfb4 ,outl9e map ( lakes ,:ittlesey & ,sag9aw #ccc #cfc4 ,map ( ! glacial ,lake ,w>r5 #ccc #cfd4 ,map ( ! glacial ,lake ,algonqu9 #ccd #cfe4 ,outl9e map ( ! ,nipiss+ ,great ,lakes #cce #cff4 ,probable preglacial dra9age ( ! upp] ,ohio region #ccg #cfg4 ,diagrams to illu/rate ! episodes 9 ! rec5t hi/ory ( a ,connecticut riv] #cch #cfh4 ,! not*$ rock headl& ( ,boy] ,bluff on ,lake ,mi*igan #cda #cfi4 ,view ( ,mack9ac ,isl& f ! direction ( ,/4 ,ignace #cdb #cgj4 ,! 8,sug> ,loaf01 a /ack ( ,lake ,algonqu9 ^u ,mack9ac ,isl& #cdb #cga4 ,bea* ridges 9 s]ies on ,mack9ac ,isl& #cdc #cgb4 ,not*$ /ack ( ! ,nipiss+ ,great ,lakes at ,/4 ,ignace #cdc #cgc4 ,s]ies ( diagrams to illu/rate ! evolution ( ideas conc]n+ ! uplift ( ! lake region s9ce ! ,ice ,age #cdd #cgd4 ,map ( ! ,great ,lakes region to %[ ! isobases & h+e l9es ( uptilt #cde #cge4 ,s]ies ( diagrams to indicate ! nature ( ! recov]y ( ! cru/ by uplift :5 unload$ ( an ice mantle #cdf #cgf4 ,portion ( ! ,inn] ,s&usky ,bay1 = comp>ison ( ! %ore l9e ( #ahbj ) t ( to-day #cej #cgg4 ,ideal cross section ( ! ,niag>a ,gorge to %[ ! m>g9al t]race #cec #cgh4 ,view ( ! b$ ( ! ,niag>a ,riv] above ! cat>act :]e wat] has be5 dra9$ (f #cec #cgi4 ,view ( ! ,falls ( ,/4 ,an?ony 9 #ahea #ced #chj4 ,ideal section to %[ ! nature ( ! drill+ process b5ea? ! cat>act #cee #cha4 ,plan & section ( ! gorge1 %[+ h[ ! dep? is proportional to ! wid? #cee #chb4 ,comp>ative views ( ! ,canadian ,falls 9 #ahbg & #ahie #cef #chc4 ,map to %[ ! recession ( ! ,canadian ,fall #ceg #chd4 ,comp>ison ( ! pres5t ) ! future falls #ceh #che4 ,bird's-eye view ( ! captur$ ,canadian ,fall at ,w9t]gre5 ,flats #ceh #chf4 ,map ( ! ,:irlpool ,bas9 #cfj #chg4 ,map ( ! cue/as :i* h play$ s important a "p 9 fix+ ! b\nd>ies ( ! lake bas9s #cfa #chh4 ,bird's-eye view ( ! cue/as s\? ( ,lakes ,ont>io & ,erie #cfb #chi4 ,sket* map ( ! great] portion ( ! ,niag>a ,gorge to illu/rate ,niag>a hi/ory #cfc #cij4 ,sn[drift holl[+ its b$ by nivation #cfh #cia4 ,amphi!at] =m$ ^u a drift site 9 nor!rn ,lapl& #cfi #cib4 ,! m>g9al crevasse on ! highe/ m>g9 ( a glaci] #cgj #cic4 ,ni*es & cirques 9 ! ,bighorn ,m\nta9s ( ,wyom+ #cga #cid4 ,subord9ate cirques 9 ! amphi!at] on ! we/ face ( ! ,wannehorn #cga #cie4 8,biscuit cutt+0 effect ( glacial sculpture 9 ! ,u9ta ,m\nta9s ( ,wyom+ #cgb #cif4 ,diagram to %[ ! cause ( ! hyp]bolic curve ( cols #cgb #cig4 ,a col 9 ! ,selkirks #cgc #cih4 ,diagrams to illu/rate ! =mation ( comb ridges1 cols1 & horns #cgd #cii4 ,! ,u-%ap$ ,k]n ,valley 9 ! ,si]ra ,nevadas ( ,cali=nia #cge #djj4 ,glaciat$ valley wall1 %[+ ! %>p l9e :i* sep>ates ! abrad$ f ! und]m9$ rock surface #cge #dja4 ,view ( ! ,vale ( ,*amonix f ! sracs ( ! ,glaci] des ,bossons #cgf #djb4 ,map ( an area ne> ! cont95tal divide 9 ,colorado #cgg #djc4 ,gorge ( ! ,albula ,riv] 9 ! ,engad9e cut ?r\gh a rock b> #cgh #djd4 ,ideali/ic sket*1 %[+ glaciat$ & nonglaciat$ side valleys #cgh #dje4 ,"* pr(iles sculptur$ by m\nta9 glaci]s #cgi #djf4 ,flat dome %ap$ "u ! m>g9 ( a ,norwegian ice cap #cgi #djg4 ,two views :i* illu/rate successive /ages 9 ! %ap+ ( t9ds #chj #djh4 ,s*ematic diagram to br+ out ! relation%ips ( ! v>i\s types ( m\nta9 glaci]s #chc #dji4 ,map ( ! ,malasp9a ,glaci] ( ,alaska #chd #daj4 ,map ( ! ,baltoro ,glaci] ( ! ,himalayas #che #daa4 ,view ( ! ,trie/ ,glaci]1 a hang+ glaci]et #che #dab4 ,map ( ! ,h>riman ,fjord ,glaci] ( ,alaska #chf #dac4 ,map ( ! ,rotmoos ,glaci]1 a radiat+ glaci] ( ,switz]l& #chf #dad4 ,outl9e map ( ! ,asulkan ,glaci] 9 ! ,selkirks1 a horse%oe glaci] #chg #dae4 ,outl9e map ( ! ,illecillewaet ,glaci] ( ! ,selkirks1 an inh]it$-bas9 glaci] #chh #daf4 ,diagram to illu/rate ! surface fl[ ( glaci]s #cij #dag4 ,diagram to %[ ! trans=mation ( crevasses into sracs #cia #dah4 ,view ( ! ,glaci] des ,bossons1 %[+ ! position ( accid5ts to ,alp9i/s #cib #dai4 ,l9es ( fl[ ^u ! surface ( ! ,h9t]eisf]n] ,glaci] 9 ! ,alps #cic #dbj4 ,lat]al & m$ial mora9es ( ! ,m] de ,glace & its tribut>ies #cic #dba4 ,ideal cross section ( a m\nta9 glaci] #cid #dbb4 ,diagrams to illu/rate ! melt+ effects ^u glaci] ice ( rock fragm5ts ( diff]5t sizes #cid #dbc4 ,small glaci] table ^u ! ,great ,alets* ,glaci] #cie #dbd4 ,effects ( diff]5tial melt+ & subsequ5t refreez+ ^u a glaci] surface #cif #dbe4 ,dirt cone ) its cas+ 9 "p remov$ #cif #dbf4 ,s*ematic diagram to %[ ! mann] ( =mation ( glaci] cornices #cig #dbg4 ,sup]glacial /ream ^u ! ,great ,alets* ,glaci] #cih #dbh4 ,ideal =m ( ! surface left on ! site ( a pi$mont glaci] apron #cii #dbi4 ,map ( ! site ( ! e>li] pi$mont glaci] ( ! ,upp] ,rh9e #cii #dcj4 ,diagram & map to br+ out ! *>act]i/ics ( newl& lakes #djb #dca4 ,view ( ! ,w>n] ,lakes1 ,oregon #djb #dcb4 ,s*ematic diagram to illu/rate ! *>act]i/ics ( bas9-range lakes #djc #dcc4 ,s*ematic diagram ( rift-valley lakes & ! valley ( ! ,jordan #djc #dcd4 ,map ( ! rift-valley lakes ( ,ea/ ,c5tral ,africa #djd #dce4 ,e>?quake lakes =m$ 9 #ahaa 9 ! flood pla9 ( ! ,l[] ,mississippi #djd #dcf4 ,view ( a crat] lake 9 ,co/a ,rica #dje #dcg4 ,diagrams to illu/rate ! *>act]i/ics ( crat] lakes #djf #dch4 ,view ( ,snag ,lake1 a c\le lake 9 ,cali=nia #djf #dci4 ,diagrams to illu/rate ! *>act]i/ics ( mora9al lakes #djg #ddj4 ,diagram to %[ ! mann] ( =mation ( pit lakes #djh #dda4 ,diagrams to illu/rate ! *>act]i/ics ( pit lakes #djh #ddb4 ,diagram to %[ ! mann] ( =mation ( gl9t lakes #dji #ddc4 ,map ( a s]ies ( gl9t lakes on ! b\nd>y ( ,sw$5 & ,norway #dji #ddd4 ,map ( ice-dam lakes ne> ! ,norwegian b\nd>y ( ,sw$5 #daj #dde4 ,wave-cut t]race ( a =m] ice-dam lake 9 ,sw$5 #daj #ddf4 ,view ( ! ,mrjel5 ,lake f ! summit ( ! ,eggi%orn #daa #ddg4 ,diagrams to illu/rate ! arrangem5t & ! *>act]s ( rock-bas9 lakes #dab #ddh4 ,convict ,lake1 a valley-mora9e lake ( ,cali=nia #dac #ddi4 ,lake bas9s produc$ by successive slides f ! /eep walls ( a glaciat$ m\nta9 valley #dad #dej4 ,lake ,g>da1 a bord] lake ^u ! site ( a pi$mont apron #dad #dea4 ,diagrams to br+ out ! *>act]i/ics ( ox-b[ lakes #dae #deb4 ,diagrammatic section to illu/rate ! =mation ( sauc]-l bas9s betwe5 ! levees ( /reams on a flood pla9 #dae #dec4 ,sauc] lakes ^u ! b$ ( ! =m] riv] ,w>r5 #daf #ded4 ,levee lakes develop$ 9 s]ies )9 me&]s 9 a delta pla9 #dag #dee4 ,raft lakes along ! banks ( ! ,r$ ,riv] 9 ,arkansas & ,l\isiana #dah #def4 ,map ( ! ,swiss lakes ,?un & ,bri5z #dai #deg4 ,delta lakes =m$ at ! m\? ( ! ,mississippi #dai #deh4 ,delta lakes at ! m>g9 ( ! ,nile delta #dbj #dei4 ,diagrams to illu/rate ! *>act]i/ics ( b>ri] lakes #dbj #dfj4 ,dune lakes on ! coa/ ( ,france #dba #dfa4 ,s9k lakes 9 ,florida1 ) a s*ematic diagram to illu/rate ! mann] ( _! =mation #dba #dfb4 ,map ( ! ,arve & ! ,upp] ,rhone #dbf #dfc4 ,view ( ! ,arve & ! ,rhone at _! junction #dbg #dfd4 ,a village 9 ,switz]l& built ^u a /ra? at ! head ( ,lake ,pos*iavo #dbh #dfe4 ,view ( ! float+ bog & surr\nd+ zones ( vegetation 9 a small glacial lake #dbi #dff4 ,diagram to %[ h[ small lakes are trans=m$ into peat bogs #dcj #dfg4 ,map to %[ ! anomal\s position ( ! delta 9 ,lake ,/4 ,clair #dca #dfh4 ,a b[ld] wall ^u ! %ore ( a small lake #dcb #dfi4 ,diagrams to %[ ! effect ( ice %ove 9 produc+ ice ramp>ts ^u ! %ores ( lakes #dcc #dgj4 ,v>i\s =ms ( ice ramp>ts #dcc #dga4 ,map ( ,lake ,m5dota1 %[+ ! position ( ! ridge :i* =ms f ice expansion & ! ice ramp>ts ^u ! %ores #dcd #dgb4 ,! great multiple m\nta9 arc ( ,sewe/an1 ,briti% ,india #dcf #dgc4 ,diagrams to illu/rate ! !ories ( orig9 ( m\nta9 arcs #dcg #dgd4 ,fe/oons ( m\nta9 arcs ab\t ! bord]s ( ! ,pacific ,ocean #dch #dge4 ,! int]rupt$ ,armorican ,m\nta9s common to we/]n ,europe & ea/]n ,nor? ,am]ica #dch #dgf4 ,a zone ( div]se displacem5t 9 ! we/]n ,unit$ ,/ates #dci #dgg4 ,section ( an ,ea/ ,african block m\nta9 #dci #dgh4 ,tilt$ cru/ blocks 9 ! ,queant[eap valley #ddj #dgi4 ,view ( ! laccolite ( ! ,c>riso ,m\nta9 #dda #dhj4 ,map ( laccolitic m\nta9s #dda #dha4 ,ideal sections ( laccolite & bysmalite #ddb #dhb4 ,! gabl$ faade l>gely develop$ 9 des]t l&scapes #ddc #dhc4 ,balloon view ( ! ,my!n 9 ,switz]l& #ddd #dhd4 ,! battlem5t type ( erosion m\nta9 #dde #dhe4 ,symmetrically =m$ l[ isl&s repeat$ 9 ranks ^u ,temagami ,lake1 ,ont>io #dde #dhf4 ,=ms ( cry/als ( a numb] ( m9]als #ded #dhg4 ,=ms ( cry/als ( a numb] ( m9]als #deg #dhh4 ,a /ud5t's cont\r map #dfi #dhi4 ,models to repres5t outcrops ( rock #dgb #dij4 ,special laboratory table set ) a problem 9 geological mapp+ :i* is solv$ 9 ,figs4 #dg & #dh #dgb #dia4 ,?ree field maps to be us$ z sugge/ions 9 arrang+ laboratory table = problems 9 ! prep>ation ( areal geological maps #dgc #dib4 ,sket* map ( ,we/]n ,scotl& & ! ,inn] ,hebrides to %[ location ( "s po9ts ( special geological int]e/ #dha #dic4 ,outl9e map ( a geological pilgrimage across ! cont95t ( ,europe #dhc ,,explanatory ,,li/ ,,( ,,abbreviations ,,= ,,j\rnal ,,names ,,9 ,,read+ ,,ref]5ces ,am4 ,geol43 ,am]ican ,geologi/4 ,am4 ,j\r4 ,sci43 ,am]ican ,j\rnal ( ,sci5ce1 ,new ,hav54 ,ann4 de ,gogr43 ,annales de ,gographie1 ,p>is4 ,ann4 ,rept4 ,geol4 & ,geogr4 ,surv4 ,t]43 ,annual ,report ( ! ,geological & ,geographical ,survey ( ! ,t]ritories 7,hayd571 ,wa%+ton4 ,ann4 ,rept4 ,geol4 & ,nat4 ,hi/4 ,surv4 ,m9n43 ,annual ,report ( ! ,geological & ,natural ,hi/ory ,survey ( ,m9nesota1 ,m9neapolis4 ,ann4 ,rept4 ,mi*4 ,geol4 ,surv43 ,annual ,report ( ! ,mi*igan ,geological ,survey1 ,lans+4 ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv43 ,annual ,report ( ! ,unit$ ,/ates ,geological ,survey1 ,wa%+ton4 ,bull4 ,am4 ,geogr4 ,soc43 ,bullet9 ( ! ,am]ican ,geographical ,society1 ,new ,york4 ,bull4 ,e>?q4 ,inv4 ,com4 ,japan3 ,bullet9 ( ! ,e>?quake ,inve/igation ,committee ( ,japan1 ,tokyo4 ,bull4 ,geogr4 ,soc4 ,philadelphia3 ,bullet9 ( ! ,geographical ,society ( ,philadelphia4 ,bull4 ,geol4 ,soc4 ,am43 ,bullet9 ( ! ,geological ,society ( ,am]ica4 ,bull4 ,mus4 ,comp4 ,zol43 ,bullet9 ( ! ,museum ( ,comp>ative ,zology1 ,h>v>d ,college1 ,cambridge4 ,bull4 ,n4 ,y4 ,/ate ,mus43 ,bullet9 ( ! ,new ,york ,/ate ,museum1 ,albany4 ,bull4 ,soc4 ,belge d',a/ronomie3 ,bullet9 de la ,socit ,belge d',a/ronomie1 ,brussels4 ,bull4 ,soc4 ,belge ,gol43 ,bullet9 de la ,socit ,belge de ,gologie1 ,brussels4 ,bull4 ,soc4 ,sc4 ,nat4 ,neu*tel3 ,bullet9 de la ,socit des ,sci5ces ,naturelles de ,neu*tel4 ,bull4 ,univ4 ,calif4 ,dept4 ,geol43 ,bullet9 ( ! ,univ]sity ( ,cali=nia1 ,dep>tm5t ( ,geology1 ,b]keley4 ,bull4 ,u4 ,s4 ,geol4 ,surv43 ,bullet9 ( ! ,unit$ ,/ates ,geological ,survey1 ,wa%+ton4 ,bull4 ,wis4 ,geol4 & ,nat4 ,hi/4 ,surv43 ,bullet9 ( ! ,wiscons9 ,geological & ,natural ,hi/ory ,survey1 ,madison4 ,c4 ,r4 ,cong4 ,gol4 ,int]n43 ,comptes ,r5dus de la ,congrs ,gologique ,int]nationale4 ,dept4 ( ,m9es1 ,geol4 ,surv4 ,bran*1 ,canada3 ,dep>tm5t ( ,m9es1 ,geological ,survey ,bran*1 ,canada4 ,geogr4 ,abh43 ,geographis*e ,abh&lung54 ,geogr4 ,j\r43 ,geographical ,j\rnal1 ,london4 ,geol4 ,folio ,u4 ,s4 ,geol4 ,surv43 ,geological ,folio ( ! ,unit$ ,/ates ,geological ,survey4 ,geol4 ,mag43 ,geological ,magaz9e1 ,london 7sections designat$ by decades74 ,j\r4 ,am4 ,geogr4 ,soc43 ,j\rnal ( ! ,am]ican ,geographical ,society1 ,new ,york4 ,j\r4 ,coll4 ,sci4 ,imp4 ,univ4 ,tokyo3 ,j\rnal ( ! ,college ( ,sci5ce ( ! ,imp]ial ,univ]sity1 ,tokyo1 ,japan4 ,j\r4 ,geol43 ,j\rnal ( ,geology1 ,*icago4 ,j\r4 ,s*4 ,geogr43 ,j\rnal ( ,s*ool ,geography4 ,livret ,guide ,cong4 ,gol4 ,int]n43 ,livret ,guide ,congrs ,gologique ,int]nationale4 ,mem4 ,geol4 ,surv4 ,india3 ,memoirs ( ! ,geological ,survey ( ,india1 ,calcutta4 ,mitt4 ,geogr4 ,ges4 ,hamb43 ,mitteilung5 d] ,geographis*e ,gesells*aft1 ,hamburg4 ,mon4 ,u4 ,s4 ,geol4 ,surv43 ,monograph ( ! ,unit$ ,/ates ,geological ,survey1 ,wa%+ton4 ,nat4 ,geogr4 ,mag43 ,national ,geographic ,magaz9e1 ,wa%+ton4 ,nat4 ,geogr4 ,mon43 ,national ,geographic ,monographs1 ,am]ican ,book ,company1 ,new ,york4 ,naturw4 ,wo*5s*r43 ,naturwiss5s*aftli*e ,wo*5s*rift4 ,pet4 ,mitt43 ,pet]manns ,mit!ilung5 aus ,ju/us ,p]!s' ,geographis*] ,an/alt1 ,go?a4 ,pet4 ,mitt41 ,ergnzung%4 or ,erg43 ,pet]manns ,mit!ilung51 ,go?a 7,ergnzung%eft or ,supplem5t>y ,pap]74 ,phil4 ,j\r4 ,sci43 ,philipp9e ,j\rnal ( ,sci5ce1 ,manila4 ,phil4 ,trans43 ,philosophical ,transactions ( ! ,royal ,society1 ,london4 ,proc4 ,am4 ,acad4 ,arts & ,sci43 ,proce$+s ( ! ,am]ican ,academy ( ,arts & ,sci5ces4 ,proc4 ,am4 ,assoc4 ,adv4 ,sci43 ,proce$+s ( ! ,am]ican ,association = ! ,advancem5t ( ,sci5ce4 ,proc4 ,am4 ,phil4 ,soc43 ,proce$+s ( ! ,am]ican ,philosophical ,society1 ,philadelphia4 ,proc4 ,bo/4 ,soc4 ,nat4 ,hi/43 ,proce$+s ( ! ,bo/on ,society ( ,natural ,hi/ory1 ,bo/on4 ,proc4 ,ind4 ,acad4 ,sci43 ,proce$+s ( ! ,indiana ,academy ( ,sci5ce4 ,proc4 ,l9n4 ,soc4 ,new ,s\? ,wales3 ,proce$+s ( ! ,l9nean ,society ( ,new ,s\? ,wales4 ,proc4 ,ohio ,/ate ,acad4 ,sci43 ,proce$+s ( ! ,ohio ,/ate ,academy ( ,sci5ce4 ,pr(4 ,pap4 ,u4 ,s4 ,geol4 ,surv43 ,pr(essional ,pap] ( ! ,unit$ ,/ates ,geological ,survey1 ,wa%+ton4 ,pub4 ,c>neg4 ,in/43 ,publication ( ! ,c>negie ,in/itution ( ,wa%+ton4 ,pub4 ,mi*4 ,geol4 & ,biol4 ,surv43 ,publication ( ! ,mi*igan ,geological & ,biological ,survey1 ,lans+4 ,qu>t4 ,j\r4 ,geol4 ,soc4 ,lond43 ,qu>t]ly ,j\rnal ( ! ,geological ,society1 ,london4 ,rept4 ,brit4 ,assoc4 ,adv4 ,sci43 ,report ( ! ,briti% ,association = ! ,advancem5t ( ,sci5ce4 ,rept4 ,geol4 ,surv4 ,mi*43 ,report ( ! ,geological ,survey ( ,mi*igan1 ,lans+4 ,rept4 ,mi*4 ,acad4 ,sci43 ,report ( ! ,mi*igan ,academy ( ,sci5ce1 ,lans+4 ,rept4 ,nat4 ,cons]v4 ,com43 ,report ( ! ,national ,cons]vation ,commission1 ,wa%+ton4 ,rept4 ,smi?son4 ,in/43 ,report ( ! ,smi?sonian ,in/itution1 ,wa%+ton4 ,sci4 ,bull4 ,brooklyn ,in/4 ,arts & ,sci43 ,sci5ce ,bullet9 ( ! ,brooklyn ,in/itute ( ,arts & ,sci5ces4 ,scot4 ,geogr4 ,mag43 ,scotti% ,geographic ,magaz9e1 ,ed9burgh4 ,smi?4 ,cont4 to ,kn[l43 ,smi?sonian ,contributions to ,k1 ,wa%+ton4 ,te*4 ,qu>t43 ,te*nology ,qu>t]ly ( ! ,massa*usetts ,in/itute ( ,te*nology1 ,bo/on4 ,trans4 ,am4 ,in/4 ,m94 ,eng43 ,transactions ( ! ,am]ican ,in/itute ( ,m9+ ,eng9e]s1 ,new ,york4 ,trans4 ,roy4 ,dubl9 ,soc43 ,transactions ( ! ,royal ,dubl9 ,society4 ,trans4 ,seis4 ,soc4 ,japan3 ,transactions ( ! ,seismological ,society ( ,japan1 ,tokyo4 ,trans4 ,wis4 ,acad4 ,sci43 ,transactions ( ! ,wiscons9 ,academy ( ,sci5ces1 ,arts1 & ,lett]s1 ,madison4 ,u4 ,s4 ,geogr4 & ,geol4 ,surv4 ,rocky ,mt4 ,region3 ,unit$ ,/ates ,geographical & ,geological ,survey ( ! ,rocky ,m\nta9 ,region 7,p[ell71 ,wa%+ton4 ,zeit4 d4 ,gesell4 f4 ,erdk4 z4 ,b]l93 ,zeits*rift d] ,gesells*aft fr ,erdkunde zu ,b]l94 ,zeit4 f4 ,glets*]k3 ,zeits*rift fr ,glets*]kunde1 ,b]l94 ,,e>? ,,features ,,& ,,_! ,,mean+ ,,*apt] ,i ,,! ,,compilation ,,( ,,e>? ,,hi/ory ,! s\rces ( ! hi/ory4--,! sci5ce :i* deals ) ! *apt]s ( e>? hi/ory t ant$ate ! e>lie/ human writ+s is geology4 ,! pages ( ! record are ! lay]s ( rock :i* make up ! out] %ell ( our _w4 ,"h z 9 old manuscripts pages are sometimes f\nd to be miss+1 & on o!rs ! writ+ is l>gely effac$ s z to be indi/9ct or ev5 illegible4 ,an intellig5t int]pretation ( ?is record requires a k ( ! mat]ials & ! /ructure ( ! e>?1 z well z a prop] conception ( ! ag5cies :i* h caus$ *ange & s develop$ ! hi/ory4 ,^! ag5cies 9 op]ation are physical & *emical processes1 & s ! sci5ces ( physics & *emi/ry are fundam5tal 9 any ext5d$ /udy ( geology4 ,n only is geology1 s to speak1 f\nd$ ^u *emi/ry & physics1 b its field ov]laps t ( _m o!r important sci5ces4 ,! e>lie/ e>? hi/ory has to d ) ! =m1 size1 & physical condition ( a m9or planet 9 ! sol> sy/em4 ,! e>lie/ portion ( ! /ory belongs !re=e to a/ronomy1 & no %>p l9e c be drawn to sep>ate ?is *apt] f ^? lat] ones :i* are m cle>ly )9 ! doma9 ( geology4 ,subdivisions ( geology4--,! t]ms 8cosmic geology0 & 8a/ronomic geology0 h sometimes be5 us$ to cov] ! a/ronomy ( ! e>? planet4 ,! lat] e>? hi/ory develops1 among o!r ?+s1 ! v>i$ =ms ( animal & vegetable life :i* h _h a def9ite ord] ( appe>ance4 ,_! /udy is to a l>ge ext5t zology & botany1 ?\gh "h consid]$ f an ess5tially diff]5t viewpo9t4 ,?is subdivision ( our sci5ce is call$ paleontological geology or paleontology1 :i* 9 common usage includes ! plant z well z ! animal _w1 or :at is sometimes call$ paleobotany4 ,9 ord] to fix ! ord] ( ev5ts 9 geological hi/ory1 ^! biological /udies are necess>y1 = ! pages ( ! record h _m ( !m be5 misplac$ z a result ( ! vicissitudes ( e>? hi/ory1 & ! rema9s ( life 9 ! rock lay]s supply a pag9ation f :i* x is possible to correctly re>range ! misplac$ pages4 ,z compil$ into a consecutive hi/ory ( ! e>? s9ce life appe>$ ^u x1 we h ! division ( hi/orical geology2 ?\gh ?is diff]s b little f /ratigraphical geology1 ! emphasis 9 ! case ( ! =m] be+ plac$ on ! hi/ory itself & 9 ! latt] ^u ! arrangem5t ( ev5ts--! pag9ation ( ! record4 ,s f> z !y are kn[n to u1 ! mat]ials ( :i* ! e>? is compos$ are m9]als gr\p$ into v>i\s *>act]i/ic aggregates kn[n z rocks4 ,"h ! sci5ce is f\nd$ ^u m9]alogy z well z *emi/ry1 & a /udy ( ! rock mat]ials ( ! e>? is designat$ petrographical geology or petrography4 ,! v>i\s rocks :i* ent] into ! composition ( ! e>?'s out] %ell--! only portion kn[n to u f direct obs]vation--are built into x 9 an ar*itecture :i*1 :5 c>efully /udi$1 discloses important ev5ts 9 ! e>?'s hi/ory4 ,! division ( ! sci5ce :i* is conc]n$ ) e>? ar*itecture is geotectonic or /ructural geology4 ,! /udy ( e>? features & _! significance4--,! features ^u ! surface ( ! e>? h all _! deep significance1 & if prop]ly und]/ood1 a flood ( light is ?r[n1 n only ^u pres5t conditions1 b ^u _m *apt]s ( ! e>?'s e>li] hi/ory4 ,"h ! relation ( our /udy to topography & geography is v close1 s t ! l9es ( sep>ation are b ill def9$4 ,! t]ms 8physiographical geology01 8physiography01 & 8geomorphology0 are conc]n$ ) ! configuration ( ! e>?'s surface--its physiognomy--& ) ! g5esis ( its individual surface features4 ,x is ?is g5etical side ( physiography :i* sep>ates x f topography & l5ds x an absorb+ int]e/1 ?\gh x causes x to l>gely ov]lap ! division ( dynamical geology or ! /udy ( geological processes4 ,9 fact1 ! diff]5ce betwe5 dynamical geology & physiography is l>gely "o ( emphasis1 ! /ress be+ laid ^u ! processes 9 ! =m] & ^u ! resultant features 9 ! latt]4 ,"u dynamical geology are includ$ important subdivisions1 su* z seismic geology1 or ! /udy ( e>?quakes1 & vulcanology1 or ! /udy ( volcanoes4 ,ano!r l>ge subject1 glacial geology1 belongs )9 ! broad fronti] common to bo? dynamical geology & physiography4 ,a relatively new subdivision ( geological sci5ce is ori5tational geology1 :i* is conc]n$ ) ! tr5d ( e>? features1 & is closely relat$ bo? to physiography & to dynamical & /ructural geology4 ,tabul> recapitulation4--,9 a slightly diff]5t arrangem5t f ! above ord] ( m5tion1 ! subdivisions ( geology are z foll[s3-- ,subdivisions ( ,geology ,petrographical ,geology4 ,mat]ials ( ! e>?4 ,geotectonic ,geology4 ,ar*itecture ( ! e>?'s out] %ell4 ,dynamical ,geology4 ,e>? processes4 ,seismic ,geology--e>?quakes4 ,vulcanology--volcanoes4 ,glacial ,geology--glaci]s1 etc4 ,physiographical ,geology4 ,e>? physiognomy & its g5esis4 ,ori5tational ,geology4 ,! arrangem5t & ! tr5d ( e>? features4 ,9 "o way or ano!r all ( ! above subdivisions ( geology are 9 "s way conc]n$ 9 ! g5esis ( e>? physiognomy1 & !y mu/ !re=e be giv5 consid]ation 9 a "w :i* is devot$ to a /udy ( ! mean+ ( e>? features4 ,! compil$ record ( ! rocks is1 h[ev]1 some?+ q ap>t & )\t p]t95ce to ! pres5t "w4 ,z already indicat$ its subdivisions are3-- ,a/ronomic ,geology4 ,planet>y hi/ory ( ! e>?4 ,/atigraphic ,geology4 ,! pag9ation ( e>? records4 ,hi/orical ,geology4 ,! compil$ record & its int]pretation4 ,paleontological ,geology4 ,! evolution ( life ^u ! e>?4 ,9 e attempt at sy/ematic arrangem5t difficulties are enc\nt]$1 usually because no "o consid]ation c be us$ ?r\gh\t z ! basis ( classification4 ,su* t]ms z 8economic geology0 & 8m9+ geology0 h ei!r a p$agogical or a comm]cial significance1 & s w\ld h>dly fit into ! sy/em :i* we h outl9$4 ,geological processes n univ]sal4--,x is inevitable t ! geology ( regions :i* are easily accessible = /udy %\ld h absorb$ ! l>g] measure ( att5tion2 b x %\ld n be =gott5 t geology is conc]n$ ) ! hi/ory ( ! entire _w1 & t p]spective w be lo/ & errone\s conclusions drawn if local conditions are kept too (t5 be=e ! eyes4 ,to illu/rate by a s+le in/ance1 ! be/ /udi$ regions ( ! globe are ^? 9 :i* fairly abundant precipitation 9 ! =m ( ra9 has fitt$ ! l& = easy conditions ( life1 & has ?us p]mitt$ ! developm5t ( a high civilization4 ,9 degree1 & to "s ext5t also 9 k9d1 geologic processes are m>k$ly diff]5t )9 ^? widely ext5d$ regions :i*1 because ei!r arid or cold1 h be5 b ill fitt$ = human habitation4 ,yet 9 ! hi/orical developm5t ( ! e>?1 ^? geologic processes :i* obta9 9 des]t or pol> regions are none ! less important because less (t5 & less c>efully obs]v$4 ,*ange1 & n /ability1 ! ord] ( nature4--,man is ev] prone to emphasize ! importance ( app>5t facts to ! disadvantage ( ^? less cle>ly reveal$ ?\gh equally pot5t4 ,! anci5t notion ( ! t]ra firma1 ! safe & solid gr\nd1 arose because ( its contra/ ) ! f> m mobile bodies ( wat]2 b ?is illusion is quickly dispell$ ) ! sudd5 quak+ ( ! gr\nd4 ,exp]i5ce has cle>ly %[n t1 bo? ^u & b5ea? ! e>?'s surface1 *emical & physical *anges are go+ on1 subject to b little int]ruption4 8,! hills rock-ribb$ & anci5t z ! sun0 is a poetical metaphor2 = ! ,himalayas1 ! l(tie/ m\nta9s ^u ! globe1 71 to speak 9 geological t]ms1 rais$ f ! sea b ye/]day4 ,ev5 to-day !y are pu%+ up _! heads1 only to be rel5tlessly plan$ d[n ?r\gh ! action ( ! atmosph]e1 ( ice1 & ( runn+ wat]4 ,ev5 m ?an has g5]ally be5 suppos$1 ! e>? suff]s *ange4 ,(t5 )9 ! space ( a few seconds1 to ! accompanim5t ( a heavy e>?quake1 _m squ>e miles ( t]ritory are bodily uplift$1 :ile neighbor+ areas may be relatively depress$4 ,?us *ange1 & n /ability1 is ! ord] ( nature4 ,obs]vational geology v]sus speculative philosophy4--,!re appe>s to be a m or less preval5t notion t ! views :i* are held by sci5ti/s 9 "o g5]ation are ab&on$ by ^? ( ! next2 & ?is is apt to lead to ! belief t little is really kn[n & t mu* is l>gely guess$4 ,"s gr\nd !re und\bt$ly is = su* skepticism1 ?\gh mu* ( x may be acc\nt$ = by a g5]al failure among sci5ti/s1 z well z o!rs1 to cle>ly diff]5tiate t :i* is ess5tially speculative f :at is bas$ broadly ^u obs]v$ facts4 ,ev5 ) ext5d$ obs]vation1 ! possibility ( expla9+ ! facts 9 m ?an "o way is n exclud$2 b ! l9e is nev]!less a broad "o :i* sep>ates ?is entire field ( obs]vation f :at is ess5tially speculative philosophy4 ,to illu/rate3 ! me*anics ( ! action :i* goes on )9 volcanic crat]s is n[ fairly well und]/ood z a result ( _m & ext5d$ obs]vations1 & x is little likely t future g5]ations ( geologi/s w discr$it ! ma9 conclusions :i* h be5 rea*$4 ,! cause ( ! rise ( ! lava to ! e>?'s surface is1 on ! o!r h&1 mu* less cle>ly demon/rat$1 & ! views :i* are held express r ! diff]+ op9ions ?an any cle> d$uctions f obs]vation4 ,aga91 & simil>ly1 ! physical hi/ory ( ! great cont95tal glaci]s ( ! s-call$ 8ice age0 is f> m ?or\ghly kn[n ?an t ( any exi/+ glaci] ( ! same type2 b ! cause ( ! climatic *anges :i* br\ght on ! glaciation is /ill l>gely a matt] = speculation4 ,9 ! pres5t "w1 ! attempt w be1 s f> z possible1 to give an exposition ( geologic processes & ! e>? features :i* result f !m1 ) h9ts only at ^? ultimate causes :i* lie hidd5 9 ! backgr\nd4 ,! sci5tific attitude & temp]4--,! /ud5t ( sci5ce %\ld make x 8 aim1 n only cle>ly to sep>ate 9 8 /udies ! proximate f ! ultimate causes ( obs]v$ ph5om5a1 b he %\ld keep 8 m9d always op5 = rea*+ individual conclusions4 ,no doctr9es %\ld be accept$ f9ally ^u fai? m]ely1 b subject r to 8 own reason+ processes4 ,?is %\ld n be int]pret$ to mean t conc]n+ matt]s ( :i* he kn[s little or no?+ he %\ld n pay respect to ! recogniz$ au?orities2 b 8 acceptance ( any !ory %\ld be subject to review s soon z 8 own horizon has be5 suffici5tly enl>g$4 ,false !ories c\ld h>dly h endur$ s long 9 ! pa/1 _h n too great respect be5 giv5 to au?orities1 & individual reason+ processes be5 held too long 9 subjection4 ,! value ( ! hypo!sis4--,because all ! facts necess>y = a full int]pretation ( obs]v$ ph5om5a are n at "o's h&1 ?is %\ld n be made to /& 9 ! way ( provisional explanations4 ,if sci5ce is to advance1 ! use ( hypo!sis is absolutely ess5tial2 b ! p>ticul> hypo!sis adopt$ %\ld be reg>d$ z tempor>y & z indicat+ a l9e ( obs]vation or ( exp]im5tation :i* is to be foll[$ 9 te/+ x4 ,?us reg>d$ ) an op5 m9d1 inadequate hypo!ses are ev5tually f\nd to be unt5able1 :]eas correct explanations ( ! facts by ! same process are confirm$4 ,mo/ hypo!ses ( sci5ce are b p>tially correct1 = we n[ 8see ?r\gh a glass d>kly02 b ev5 s1 if prop]ly te/$1 ! false elem5ts 9 ! hypo!sis are "o aft] ! o!r elim9at$ z ! embodi$ tru? is confirm$ & enl>g$4 ,?us 8work+ hypo!sis0 passes into !ory & becomes an integral "p ( sci5ce4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,i ,! mo/ compreh5sive ( g5]al geological texts writt5 9 ,engli% is ,*amb]l9 & ,salisbury's 8,geology0 9 ?ree volumes 7,h5ry ,holt1 #aijd-aijf71 ! fir/ volume ( :i* is devot$ exclusively to geological processes & _! results4 ,an abridg$ "o-volume edition ( ! "w int5d$ = use z a college text 0 issu$ 9 #aijf 7,college ,geology1 ,h5ry ,holt74 ,o!r /&>d texts are3-- ,,sir ,,ar*ibald ,,geikie4 ,text-book ( ,geology1 #d? ed4 #b vols4 ,london1 #aijb1 pp4 #adgb4 ,w4 ,b4 ,,scott4 ,an ,introduction to ,geology4 #b;d ed4 ,macmillan1 #aijg1 pp4 #haf4 ,j4 ,d4 ,,dana4 ,manual ( ,geology4 ,new edition4 ,am]ican ,book ,company1 #ahie1 pp4 #ajhg4 ,,joseph ,,leconte4 ,elem5ts ( ,geology4 7,revis$ by ,fair*ild47 ,appleton1 #aije1 pp4 #ffg4 ,a v valuable guide to ! rec5t lit]ature ( dynamical & /ructural geology is ,brann]'s 8,syllabus ( a ,c\rse ( ,lectures on ,elem5t>y ,geology0 7,/an=d ,univ]sity1 #aijh74 ,on ! relation ( geology to l&scape1 a numb] ( int]e/+ books h be5 writt53-- ,,james ,,geikie4 ,e>? ,sculpture or ! ,orig9 ( ,l&-,=ms4 ,new ,york & ,london1 #ahif1 pp4 #cig4 ,,john ,e4 ,,m>r4 ,! ,sci5tific ,/udy ( ,sc5]y4 ,me?u51 ,london1 #aijj1 pp4 #cfh4 ,,sir ,a4 ,,geikie4 ,! ,sc5]y ( ,scotl&4 #c;d ed4 ,macmillan1 ,london1 #aija1 pp4 #edj4 ,,sir ,,john ,,lubbock4 ,! ,sc5]y ( ,switz]l& & ! ,causes to :i* x is ,due4 ,macmillan1 ,london1 #ahif1 pp4 #dhj4 ,,"l ,,avebury4 ,! ,sc5]y ( ,engl&4 ,macmillan1 ,london1 #aijb1 pp4 #ecd4 ,,sir ,a4 ,,geikie4 ,l&scape 9 ,hi/ory1 & ,o!r ,essays4 ,macmillan1 ,london1 #aije1 pp4 #ceb4 ,n4 ,s4 ,,%al]4 ,aspects ( ! ,e>?4 ,scribn]s1 ,new ,york1 #ahhi1 pp4 #cdd4 ,g4 ,,de ,,la ,,noe ,,et ,,emm4 ,,de ,,m>g]ie4 ,les ,=mes du ,t]ra91 ,s]vice ,gographique de l',arme4 ,p>is1 #ahhh1 pp4 #bje1 pls4 #dh4 ,w4 ,m4 ,,davis4 ,practical ,ex]cises 9 ,physical ,geography1 ) ,accompany+ ,atlas4 ,g9n & ,co41 ,bo/on1 #aijh1 pp4 #adh1 pls4 #de4 ,,john ,,muir4 ,! ,m\nta9s ( ,cali=nia4 ,unw91 ,london1 #ahid1 pp4 #cha4 ,^u ! use & int]pretation ( topographic maps 9 illu/ration ( *>act]i/ic e>? features1 ! foll[+ are recomm5d$3-- ,r4 ,d4 ,,salisbury & ,w4 ,w4 ,,atwood4 ,! ,int]pretation ( ,topographic ,maps1 ,pr(4 ,pap41 #fj ,u4,s4 ,geol4 ,surv41 pp4 #hd1 pls4 #agj4 ,d4 ,w4 ,,johnson & ,f4 ,e4 ,,mat!s4 ,! ,relation ( ,geology to ,topography1 9 ,bre$ & ,hosm]'s ,pr9ciples & ,practice ( ,survey+1 vol4 #b4 ,wiley1 ,new ,york1 #aijh4 ,g,n,,ral ,,b]?aut4 ,topologie1 tude du ,t]ra91 ,s]vice ,gographique de l',arme4 ,p>is1 #aiji1 #b vols41 pp4 #ccj & #fgd1 pls4 #bfe4 ,! ,unit$ ,/ates ,geological ,survey issues free ( *>ge a li/ ( #ajj topographic atlas %eets :i* illu/rate ! m important physiographic types4 ,9 8 8,trait de ,gographie ,physique01 ,pr(essor ,e4 de ,m>tonne has giv5 at ! end ( ea* *apt] ! important =eign maps :i* illu/rate ! physiographic types !re describ$4 8,! ,pr9ciples ( ,geology01 by ,sir ,*>les ,lyell1 publi%$ fir/ 9 ?ree volumes1 appe>$ 9 ! ye>s #ahcj-ahcc1 & may be said to m>k ! beg9n+ ( mod]n geology4 ,lat] r$uc$ to two volumes1 an elev5? edition ( ! "w 0 issu$ 9 #ahgb 7,appleton7 & may be pr(itably read & /udi$ to-day by all /ud5ts ( geology4 ,^? famili> ) ! ,g]man language w d]ive bo? pleasure & pr(it f a p]usal ( ,neumayr's 8,erdges*i*te0 7#b;d ed4 revis$ by ,uhlig4 ,leipzig & ,vi5na1 #b vols41 #ahie-ahig71 & especially ! fir/ volume1 8,allgeme9e ,geologie40 ,a rec5t ,fr5* "w to be recomm5d$ is ,haug's 8,trait de ,gologie0 7,p>is1 #aijg74 ,"s texts ( physical geography may well be consult$1 especially ,emm4 de ,m>tonne's 8,trait de ,gographie ,physique40 ,col91 ,p>is1 #aiji1 pp4 #iaj1 pls4 #dh1 & figs4 #cif4 99 99 99 99 99 ,,note4 ,an explanatory li/ ( abbreviations us$ 9 ! read+ ref]5ces foll[s ! ,li/ ( ,illu/rations4 ,,*apt] ,,ii ,,! ,,figure ,,( ,,! ,,e>? ,! li?osph]e & its envelopes4--,! /ony "p ( ! e>? is kn[n z ! li?osph]e1 ( :i* only a ?9 surface %ell is kn[n to u f direct obs]vation4 ,! relatively unkn[n c5tral portion1 or 8core01 is sometimes ref]r$ to z ! c5trosph]e4 ,inclos+ ! li?osph]e is a wat] envelope1 ! hydrosph]e1 :i* comprises ! oceans & inl& bodies ( wat]1 & has a mass #a_/dedj t ( ! li?osph]e4 ,if uni=mly di/ribut$1 ! hydrosph]e w\ld cov] ! li?osph]e to ! dep? ( ab\t two miles1 in/ead ( be+ collect$ 9 bas9s z x n[ is4 ,?\gh app>5tly n cont9u\s1 if we take into acc\nt ! zone ( und]gr\nd wat] ^u ! cont95ts1 ! hydrosph]e may prop]ly be consid]$ z a cont9u\s film ab\t ! li?osph]e4 ,x is a fact ( mu* significance t all ! ocean bas9s are connect$1 s t ! levels are adju/$ to furni% a common record ( deposits ov] ! entire surface t is sea-cov]$4 ,envelop+ ! hydrosph]e is ! gase\s envelope1 ! atmosph]e1 ) a mass #a_/abjjjjj t ( ! li?osph]e4 ,! atmosph]e is a mixture ( ! gases oxyg5 & nitrog5 9 p>ts by volume ( "o ( ! =m] to f\r ( ! latt]1 ) a relatively small p]c5tage ( c>bon dioxide4 ,locally1 & at special seasons1 ! atmosph]e may be *>g$ ) relatively l>ge p]c5tages ( wat] vapor2 & we %all see t bo? ! c>bon dioxide & ! vapor cont5ts are ( ! utmo/ importance 9 geological processes & 9 ! influ5ce ^u climate4 ,unlike ! wat] :i* composes ! hydrosph]e1 ! gases ( ! atmosph]e are compressible4 ,=c$ d[n by ! weight ( sup]9cumb5t gas1 ! lay]s ( ! atmosph]e at ! level ( ! sea su/a9 a pressure ( ab\t fifte5 p\nds to ! squ>e in*2 b ?is pressure /eadily decreases 9 asc5d+ to high] levels4 ,f direct in/rum5tal obs]vation1 ! air has n[ be5 inve/igat$ to a height ( m ?an twelve miles f ! e>?'s surface4 ,! evolution ( ideas conc]n+ ! e>?'s figure4--,! ideas :i* 9 all ages h be5 promulgat$ conc]n+ ! figure ( ! e>? h be5 _m & v>i$4 ,?\gh among !m are n want+ ! purely speculative & fanta/ic1 x w be int]e/+ to pass 9 review su* !ories z h gr[n directly out ( obs]vation4 ,! anci5t ,hebrews & ! ,babylonians 7 dwell]s ( ! des]t1 & 9 ! m\nta9s :i* b\nd$ _! horizon !y saw ! conf9es ( ! e>?4 ,pu%+ at la/ we/w>d beyond ! m\nta9s1 !y f\nd ! ,m$it]ranean1 & ?us arriv$ at ! view t ! e>? 0 a disk ) a rim ( m\nta9s :i* 0 float$ ^u wat]4 ,! r>e b viol5t ra9falls to :i* !y 7 accu/om$--! des]t cl\dbur/--fur!r l$ !m to ! belief t ! m\nta9 rim 0 cont9u$ upw>d 9 a dome or firmam5t ( transp>5t cry/al ^u :i* ! heav5ly bodies 7 hung & f :i* out ( 8w9d[s ( heav50 ! wat] 8:i* is above ! e>?0 0 p\r$ out ^u ! e>?'s surface4 ,fanta/ic z ?is !ory may seem to-day1 x 0 f\nd$ ^u obs]vation1 & x well illu/rates ! dang]s ( reason+ f obs]vation )9 too limit$ a field4 ,z soon z m5 began to sail ! sea1 x 0 notic$ t ! wat] surface is convex1 = ! ma/s ( %ips 7 f\nd to rema9 visible long aft] _! hulls _h disappe>$ bel[ ! horizon4 ,x is difficult to say h[ soon ! idea ( ! e>?'s rotundity 0 acquir$1 b x is c]ta9ly ( great antiquity4 ,! ,dom9ican monk ,v9c5tius ( ,beauvais1 9 a "w complet$ 9 #abdd1 decl>$ t ! surfaces ( ! e>? & ! sea 7 bo? sph]ical4 ,! poet ,dante made x cle> t ^! surfaces 7 "o1 & 9 8 fam\s address ^u 8,! ,wat] & ! ,l&01 :i* 0 deliv]$ 9 ,v]ona on ! #bj? ( ,janu>y1 #acbj1 he add$ a /atem5t t ! cont95ts rise high] ?an ! ocean4 ,8 explanation ( ?is 0 t ! cont95ts are pull$ up by ! attraction ( ! fix$ />s aft] ! mann] ( attraction ( magnets1 ?us giv+ an e>ly h9t ( ! =ce ( gravitation4 ,! e>?'s rotundity may be said to h be5 fir/ prov5 :5 ,magellan's %ips 9 #aeba _h accompli%$ ! circumnavigation ( ! globe4 ,circumnavigation1 soon aft] aga9 c>ri$ out by ,sir ,francis ,drake1 prov$ t ! e>? is a clos$ body b\nd$ by curv+ surfaces 9 "p envelop$ by ! oceans & ev]y:]e by ! atmosph]e4 ,! great discov]y ( ,cop]nicus 9 #aecj t ! e>?1 l ,v5us1 ,m>s1 & ! o!r planets1 revolves ab\t ! sun z a "p ( a sy/em1 left little room = d\bt t ! figure ( ! e>? 0 ess5tially t ( a sph]e4 ,! oblat5ess ( ! e>?4--,e s*oolboy is to-day famili> ) ! fact t ! e>? dep>ts f a p]fect sph]ical figure by be+ flatt5$ at ! ends ( its axis ( rotation4 ,! pol> diamet] is usually giv5 z #a_/bii %ort] ?an ! equatorial "o4 ,?is oblat5ess ( ! sph]oid 0 prov5 by geodesi/s :5 !y came to comp>e ! l5g?s ( measur$ degrees ( arc ^u m]idians 9 high & 9 l[ latitudes4 ,illu/ration3 ,,fig4 #a4--;,diagrams to af=d a correct impression ( ! measure ( ! inequalities ^u ! e>?'s surface comp>$ to ! e>?'s radius4 ,! %ell repres5t$ 9 b is #a_/ajj ( ! e>?'s radius1 & 9 a ?is zone is magnifi$ = comp>ison ) surface inequalities4 ,! oblat5ess ( ! geoid is well und]/ood f accept$ hypo!ses to be ! result ( ! once m rapid rotation ( ! planet :5 its mat]ials 7 m pla/ic1 & h5ce m responsive to de=mation4 ,an ela/ic hoop rotat+ rapidly ab\t an axis 9 its plane appe>s to ! eye z a solid1 & becomes flatt5$ at ! ends ( its axis 9 proportion z ! velocity ( rotation is increas$4 ,l ! e>?1 ! o!r planets 9 ! sol> sy/em are simil>ly oblate & by am\nts dep5d5t on ! relative velocities ( rotation4 ,! dep>ture ( ! geoid f ! sph]ical surface1 ow+ to its oblat5ess1 is s small t 9 ! figures :i* we %all use = illu/ration x w\ld be less ?an ! ?ickness ( a l9e4 ,s9ce x is well recogniz$ & n important 9 our pres5t consid]ation1 we %all = ! "t be+ speak ( ! figure ( ! e>? 9 t]ms ( dep>tures f a /&>d sph]ical surface4 ,! arrangem5t ( oceans & cont95ts4--,!re are o!r dep>tures f a sph]ical surface ?an ! oblat5ess j ref]r$ to1 & ^! dep>tures1 :ile n l>ge1 are believ$ to be full ( significance4 ,le/ ! read] %\ld ga9 a wrong impression ( _! magnitude1 x may be well to introduce a diagram drawn to scale & repres5t+ prom95t elevations & depressions ( ! e>? 7,fig4 #a74 ,wrong impressions conc]n+ ! figure ( ! li?osph]e are sometimes ga9$ because its depressions are oblit]at$ by ! oceans4 ,! oceans are1 inde$1 useful to u 9 %[+ :]e ! depressions are locat$1 b ! figure ( ! e>? :i* we are consid]+ is ! nak$ surface ( ! rock4 ,9 a broad way1 ! e>?'s %ape w be giv5 by ! arrangem5t ( ! oceans & ! cont95ts4 ,z soon z we take up ! /udy ( ?is arrangem5t1 we f9d t q significant facts ( di/ribution are disclos$4 ,illu/ration3 ,,fig4 #b4--,map on ,m]cator's projection to %[ ! reciprocal relation ( ! l& & sea areas 7aft] ,gregory & ,arldt74 ,"o ( ! mo/ significant facts involv$ 9 ! di/ribution ( l& & sea1 is a conc5tration ( ! l& areas )9 ! nor!rn & ! seas )9 ! s\!rn hemisph]e4 ,! notewor?y exception is ! occurr5ce ( ! great & high ,ant>ctic cont95t c5t]$ ne> ! e>?'s s\? pole2 & !re are ext5sions ( ! nor!rn cont95t z n>r[+ l& masses to ! s\?w>d ( ! equator4 ,h>dly less significant ?an ! exi/5ce ( l& & wat] hemisph]es is ! reciprocal or antipodal di/ribution ( l& & sea 7,fig4 #b74 ,a ?ird fact ( significance is a dovetail+ toge!r ( sea & l& along an ea/-&-we/ direction4 ,:ile ! seas are g5]ally ,a-%ap$ & n>r[ nor?w>d1 ! l& masses are ,v-%ap$ & n>r[ s\?w>d1 b ?is occurs ma9ly 9 ! s\!rn hemisph]e4 ,la/ly1 !re is "s indication ( a belt ( sea divid+ ! l& masses into nor!rn & s\!rn portions along ! c\rse ( a great circle :i* makes a small angle ) ! e>?'s equator4 ,?us ! we/]n cont95t is ne>ly divid$ by a m$it]ranean sea1--! ,c>ibbean1--& ! ea/]n is 9 "p s divid$ by ! sep>ation ( ,europe f ,africa4 ,illu/ration3 ,,fig4 #c4--,! =m t[>d :i* ! figure ( ! e>? is t5d+1 a tetrah$ron ) symmetrically truncat$ angles4 ,! figure t[>d :i* ! e>? is t5d+4--,?us f> 9 our discussion ( ! e>?'s figure we h be5 guid$ entirely by ! pres5t di/ribution ( l& & wat]4 ,!re are1 h[ev]1 depressions ^u ! surface ( ! l&1 9 "s cases ext5d+ bel[ ! level ( ! sea1 :i* are n to-day occupi$ by wat]4 ,by f> ! mo/ notable ( ^! is ! great ,caspian ,depression1 :i* ) its ext5sion divides c5tral & ea/]n ,asia ^u ! ea/ f ,africa & ,europe ^u ! we/4 ,?is depression 0 q rec5tly occupi$ by ! sea1 & :5 add$ to ! pres5t ocean bas9s to indicate depressions ( ! li?osph]e1 x %[s t ! e>?'s figure dep>ts f ! /&>d sph]oid 9 ! direction ( ! =m repres5t$ 9 ,fig4 #c4 ,?is =m approximates to a tetrah$ron1 a figure b\nd$ by f\r equal triangul> faces1 "h ) symmetrically truncat$ angles4 ,( all regul> figures ) plane surfaces ! tetrah$ron has ! smalle/ volume = a giv5 surface1 & x pres5ts moreov] a reciprocal relation ( projection to depression4 ,e l9e pass+ ?r\gh its c5t] ?us f9ds ! surface ne>] ?an ! av]age di/ance ^u "o side & correspond+ly f>!r ^u ! o!r 7,fig4 #d74 ,a/ronomical v]sus geodetic obs]vations4--,confirmation ( ! conclusions arriv$ at f ! arrangem5t ( oceans & cont95ts has be5 secur$ 9 o!r fields4 ,x 0 po9t$ out t ! e>?'s oblat5ess 0 prov5 by comp>ison ( ! measur$ degrees ( latitude ^u ! e>?'s surface 9 l[] & high] latitudes1 ! degree be+ f\nd long] z ! pole is approa*$4 ,any v>iation f ! sph]ical surface mu/ obvi\sly increase ! size ( ! measur$ degree ( latitude 9 proportion to ! dep>ture f ! /&>d =m1 & s ! tetrah$ral figure ) "o ( its angles at ! s\? pole w require t ! degrees ( latitude be long] 9 ! s\!rn ?an !y are 9 ! nor!rn hemisph]e4 ,?is has be5 f\nd by measurem5t to be ! case1 & ! result is fur!r confirm$ by p5dulum /udies ^u ! di/ribution ( ! e>?'s attraction or gravity4 ,if less ( ! mass ( ! e>? is conc5trat$ 9 ! s\!rn hemisph]e1 its attraction z measur$ 9 vibrations ( ! p5dulum %\ld be correspond+ly small]4 ,illu/ration3 ,,fig4 #d4--;,a truncat$ tetrah$ron1 %[+ h[ ! depression ^u "o side ( ! c5t] is balanc$ by ! opposite projection4 ,o!r confirmations ( ! tetrah$ral figure ( ! e>? h be5 d]iv$ f a comp>ison ( a/ronomical data1 :i* assume ! e>? to be a p]fect sph]oid1 ) geodetic measurem5ts1 :i* are bas$ ^u direct measurem5ts4 ,?us ! arc measur$ 9 an ea/-&-we/ direction across ,europe reveal$ a diff]5t curvature ne> ! angle ( ! tetrah$ral figure f :at 0 f\nd f>!r to ! ea/w>d4 ,*anges ( figure dur+ contraction ( a sph]ical body4--,if we inquire :y ! e>? 9 cool+ %\ld t5d to approa* ! tetrah$ral figure1 an answ] is easily f\nd4 ,:5 =m$1 ! e>? appe>s to h be5 a b slightly oblate sph]oid1 or practically a sph]e--! %ape :i* ( all incloses ! mo/ space = a giv5 surface4 ,cool$ & solidifi$ at ! surface to ! temp]ature ( ! surr\nd+ air1 & ! core /ill hot & cont9u+ to lose heat1 ! core mu/ cont9ue to contract ?\gh ! out] %ell is no long] able to d s4 ,! sup]ficial area be+ ?us ma9ta9$ con/ant :ile ! volume cont9ues to dim9i%1 ! figure mu/ *ange f ! initial "o ( greate/ bulk to o!rs ( small] volume1 & ultimately1 if ! process %\ld cont9ue indef9itely1 to ! tetrah$ron1 :i* ( all regul> figures has ! m9imum volume = a giv5 surface4 ,t a contract+ sph]e does inde$ pass ?r\gh su* a s]ies ( *anges has be5 %[n by ! behavior ( contract+ soap bubbles & ( rubb] balloons1 z well z by exp]im5ts ^u ! exhau/ion ( air conta9$ 9 holl[ metal sph]es ( only mod]ate /r5g?4 ,9 all ^! in/ances1 ! ultimate =m produc$ indicates an ind5t+ ( f\r sides ( ! sph]e :i* h ! positions ( ! faces ( a tetrah$ron4 ,! late ,pr(essor ,pr9z ( ,brussels secur$ "s extremely int]e/+ results 9 :i* he obta9$ int]m$iate =ms ) six angles1 b un=tunately ^! /udies 7 n prep>$ = publication at ! "t ( 8 dea?4 ,! e>?'s dep>ture f ! sph]oid 9 ! direction ( ! modifi$ tetrah$ron is1 z we h se51 no hypo!sis1 b obs]v$ fact reveal$ 9 7#a7 ! conc5tration ( ! l& ab\t a c5tral ocean 9 ! nor!rn hemisph]e2 9 7#b7 ! antipodal relation ( ! l& to ! wat] areas1 & 9 7#c7 ! ?reefold subdivision ( ! surface into nor? & s\? belts by ! two great] oceans & ! ,caspian ,depression4 ,! e>li] figures ( ! e>?4--,! mann] 9 :i* cont95t & ocean are dovetail$ into ea* o!r 9 an ea/-&-we/ direction has be5 g5]ally adduc$ z additional evid5ce = ! tetrah$ral figure z above describ$4 ,clos] exam9ation %[s t in/ead ( be+ 9 h>mony ) ?is figure1 x indicates a dep>ture f x1 &1 z we %all see1 a significant dep>ture :i* und\bt$ly has its orig9 9 ! e>li] hi/ory ( ! planet4 ,! m$it]ranean seas ( bo? ! ea/]n & ! we/]n hemisph]es likewise int]f]e ) ! p]fection ( ! tetrah$ral figure & require an explanation4 ,let u !n exam9e 9 outl9e ! pa/ hi/ory ( ! _w ) ref]5ce especially to ! evolution ( ! cont95ts & to ! times & ! mann]s ( surface *ange4 ,x is n[ well kn[n t !re h be5 ?ree major p]iods ( great de=mation ( ! e>?'s %ell4 ,! fir/ ( ^! ( :i* we h record came at ! end ( ! fir/ great era ( geologic hi/ory1 ! s-call$ ,eozoic era2 a second great trans=mation came at ! close ( ! second or ,paleozoic era2 & a ?ird began at ! end ( ! next or ,mesozoic era1 an adju/m5t :i* is app>5tly cont9u+ to-day4 ,ea* ( ^! great surface de=mations 0 accompani$ by great volcanic eruptions ( :i* we h ! evid5ce 9 ! lavas rema9+ = our inspection1 & ea* 0 foll[$ by ! =mation ( great glaci]s :i* spread ov] l>ge areas ( ! exi/+ cont95ts4 ,be=e ! e>lie/ ( ^! great *anges1 ! e>? appe>s to h approximat$ 9 its figure some:at closely to ! ideal sph]oid1 = x 0 ev]y:]e envelop$ 9 ! hydrosph]e z a univ]sal ocean4 ,t[>d ! close ( ?is p]iod came ! adju/m5ts :i* br\ght ! li?osph]e to protrude ?r\gh ! hydrosph]e 9 %ield-l cont95ts ^: di/ribution1 z %[n by ! rocks ( ?is p]iod1 is ( great significance4 ,)9 ! nor!rn hemisph]e rose ?ree l& %ields spac$ at ne>ly equal int]vals & at ne>ly equal di/ances f ! nor!rn pole4 ,"o ( ^! 0 c5t]$ :]e n[ is ,hudson ,bay1 ano!r ab\t ! pres5t ,baltic ,sea1 & ! relics ( ! ?ird are f\nd 9 nor!a/]n ,sib]ia4 ,^! e>lie/ cont95ts h be5 ref]r$ to z ! ,laur5tian1 ,baltic1 & ,ang>a %ields4 ,)9 ! s\!rn hemisph]e %ields appe> to h develop$ 9 some:at simil> gr\p+1 namely1 9 ,s\? ,am]ica1 9 ,s\? ,africa1 & 9 ,au/ralia 7,figs4 #c & #e74 ,illu/ration3 ,,fig4 #e4--;,approximations to e>li] & pres5t figures ( ! e>?4 ,^! coigns or angles ( a =m into :i* ! e>li] sph]oid ( ! e>? 0 be+ trans=m$ h p]si/$ ?r\gh ! great] "p ( subsequ5t geologic "t1 & h be5 enl>g$ by ! gr[? ( s$im5ts ab\t !m z well z by ! lat] elevation & wr9kl+ ( ^! deposits into m>g9al m\nta9 ranges4 ,! cont95ts & oceans :i* arose at ! close ( ! ,paleozoic era4--,at ! close ( ! second great era 9 ! record$ hi/ory ( ! e>?1 ! n[ some:at enl>g$ cont95ts 7 pr(\ndly alt]$ dur+ a s]ies ( convulsive movem5ts )9 ! surface %ell ( ! li?osph]e4 ,:5 ^! convulsions 7 ov]1 !re 0 a new disposition ( l& & sea1 b "o q diff]5t f ! pres5t arrangem5t4 ,in/ead ( be+ ext5d$ 9 nor?-s\? belts1 z !y are at pres5t1 ! cont95ts /ret*$ out 9 broad ea/-we/ zones1 "o 9 ! nor!rn & ! o!r 9 ! s\!rn hemisph]e4 ,to ! broad s\!rn cont95t ( :i* s little n[ rema9s1 ! "n 8,gondwana ,l&0 has be5 giv51 & to ! sea :i* divid$ ! nor!rn f ! s\!rn cont95t ! "n 8,ocean ( ,te?ys40 ,! nor!rn cont95t /ret*$ across ! site ( ! pres5t ,atlantic ,ocean z ! 8,nor? ,atlantis01 its nor!rn %ore to ! we/w>d be+ some:at f>!r s\? ?an ! pres5t nor!rn coa/ ( ,nor? ,am]ica1 s9ce life =ms migrat$ 9 ! nor!rn ocean f ! site ( ,behr+ ,sea to t ( ! pres5t ,nor? ,atlantic4 ,?is arrangem5t ( l& & wat] dur+ ! middle p]iod ( ! e>?'s record$ hi/ory1 :5 consid]$ ) ref]5ce bo? to its e>li] & to its lat] evolution1 may p]haps be be/ acc\nt$ = by ! assumption t ! li?osph]e 0 !n %ap$ l ,fig4 #e 7middle74 ,9 ?is figure two truncat$ tetrah$rons are jo9$ 9 a common plane ( contact :i* may be describ$ z ! tw9 plane4 ,?is m$ial depression ^u ! li?osph]e 0 occupi$ by ! int]cont95tal sea1 ! ,ocean ( ,te?ys4 ,ne> ! close ( ?is second great era ( ! e>?'s cont95tal hi/ory1 cru/al convulsions1 :i* 7 p]haps ! mo/ rem>kable 9 ! entire record1 result$ 9 ! almo/ complete disappe>ance ( ! s\!rn cont95t & a conc5tration ( ! l& )9 ! nor!rn hemisph]e z a some:at int]rupt$ belt surr\nd+ a c5tral pol> ocean 7,figs4 #c & #e74 ,^u ! assumption ( tw9 tetrah$rons 9 ! int]m$iate era ( cont95tal evolution1 bo? ! ,ocean ( ,te?ys ( t "t & its pres5t remnants1 ! ,c>ibbean & ,m$it]ranean seas1 are acc\nt$ =4 ,! ,v-%ap$ cont95t ext5sions & ! ,a-%ap$ oceans ( ! s\!rn hemisph]e 7,fig4 #b7 may likewise be consid]$ z relics ( ! n[ l>gely subm]g$ tetrah$ron ( ! s\!rn hemisph]e1 s9ce ?is _h its apex to ! nor?w>d 7,fig4 #f74 ,illu/ration3 ,,fig4 #f4--;,diagrams = comp>ison ( %ore l9es ^u tetrah$rons :i* h an angle1 ! fir/ at ! s\? & ! second at ! nor?4 ,?us we see t ! li?osph]e c sc>cely be reg>d$ z a p]fect sph]oid1 s9ce 9 ! c\rse ( geologic ages x has und]gone successive dep>tures f ?is orig9al =m4 ,9 its pres5t /ate x has be5 describ$ z tetrah$ral1 ?\gh we mu/ keep 9 m9d t ! %>p angles ( t figure are deeply truncat$4 ,! s\nd+s fir/ by ,nans5 & m rec5tly by ,pe>y 9 ! ,arctic bas91 f> to ! nor? ( ! cont95tal bord]1 %[$ t ?is depression is *>act]iz$ by pr(\nd dep?s1 & s h af=d$ confirmation ( ! tetrah$ral figure4 ,to mat* ?is depression at ! nor!rn extremity ( ! e>?'s axis1 a high cont95t rea*+ to elevations 9 excess ( #aj1jjj feet has be5 p5etrat$ by ,sir ,erne/ ,%ackleton at ! opposite extremity ( ?is pol> diamet]4 ,consid]+ its size & its elevation1 ! ,ant>ctic cont95t ) its glaci] mantle is ! l>ge/ protub]ance ^u ! surface ( ! li?osph]e4 ,9 our /udy ( ! dep>tures ( ! e>? f ! /&>d sph]oidal surface1 we might ev5 g a /ep f>!r & %[ h[ ! tetrah$ron1 :i* be/ repres5ts ! symmetry ( ! pres5t figure1 is some:at de=m$ by a flatt5+ p]p5dicul> to ! ,pacific ,ocean4 ,to draw att5tion to ?is flatt5+ ( ! e>?1 x has sometimes be5 describ$ z 8potato-%ap$01 s9ce ! outl9e p]p5dicul> to ?is face is imp]fectly he>t-%ap$ or l a flatt5$ 8peg top40 ,illu/ration3 ,,fig4 #g4--,! cont95ts ) subm]g$ portions add$ 7aft] ,gilb]t74 ,! flood$ portions ( ! pres5t cont95ts4--,we are accu/om$ to ?9k ( ! cont95ts z end+ at ! %ores ( ! oceans4 ,if1 h[ev]1 we are to reg>d !m z plat=ms :i* rise f ! ocean depressions1 _! m>g9s %\ld be consid]ably ext5d$1 = a subm]g$ %elf n[ practically surr\nds all ! cont95ts to a ne>ly uni=m dep? ( #ajj fa?oms or #fjj feet4 ,! oceans ?us m ?an fill _! bas9s & may be ?\ght ( z spill+ ov] ^u ! cont95ts4 ,9 ,fig4 #g1 ! subm]g$ portions ( ! cont95ts h be5 jo9$ to ^? usually repres5t$1 ?us add+ ab\t #aj1jjj1jjj squ>e miles to _! area1 & giv+ !m "o ?ird1 in/ead ( "o f\r?1 ( ! li?osph]e surface4 ,illu/ration3 ,,fig4 #h4--;,diagram to indicate ! altitude ( diff]5t p>ts ( ! li?osph]e surface4 ,! floors ( ! hydrosph]e & atmosph]e4--,! highe/ altitudes ^u ! cont95ts & ! pr(\nde/ deeps ( ! ocean are ea* remov$ ab\t #cj1jjj feet1 or ne>ly #f miles1 f ! level ( ! sea4 ,9 comp>ison ) ! entire surface ( ! li?osph]e1 ^! extremes ( elevation repres5t su* small areas z to be almo/ inappreciable4 ,only ab\t #a_/hj ( ! li?osph]e surface rises m ?an #fjjj feet above sea level1 & ab\t ! same proportion lies deep] ?an #ah1jjj feet bel[ ! same datum plane 7,fig4 #h74 ,almo/ ! entire area ( ! li?osph]e is includ$ ei!r 9 ! s-call$ cont95tal plateau or plat=m1 9 ! oceanic plat=m1 or 9 ! slope :i* sep>ates ! two4 ,! cont95tal plat=m includes ! cont95tal %elf above ref]r$ to1 & repres5ts ab\t "o ?ird ( ! entire area ( ! planet4 ,?is plat=m has a range ( elevation f #fjjj feet above to #fjj feet bel[ sea level & has an av]age altitude ( ab\t #bcjj feet4 ,! oceanic plat=m slopes m /eeply1 ranges 9 dep? f #ab1jjj to #ah1jjj feet bel[ sea level1 & comprises ab\t "o half ! li?osph]e surface4 ,! rema9+ portion ( ! surface1 some?+ less ?an "o eigh? ( all1 is includ$ 9 ! /eep slopes betwe5 ! two plat=ms1 betwe5 #fjj & #ab1jjj feet bel[ sea4 ,! two plat=ms & ! slope betwe5 !m mu/ n1 h[ev]1 be ?\ght ( z cont9u\s features ^u ! surface1 b m]ely z repres5t+ ! av]age elevations ( portions ( ! li?osph]e4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,ii ,on ! evolution ( ideas conc]n+ ! e>?'s figure3-- ,,suess4 ,! ,face ( ! ,e>? 7,cl>5don ,press1 #aijf71 vol4 #b1 ,*apt] #a4 ,v4 ,,zittel4 ,hi/ory ( ,geology & ,paleontology 7,walt] ,scott1 ,london1 #aija71 ,*apt]s #a-b4 ,! dep>ture ( ! sph]oid t[>d ! tetrah$ron3-- ,w4 ,,l[?ian ,,gre54 ,ve/iges ( ! ,molt5 ,globe1 ,"p #a4 ,london1 #ahge4 7,n[ a r>e "w1 b x conta9s ! orig9al /atem5t ( ! idea47 ,j4 ,w4 ,,gregory4 ,! ,plan ( ! ,e>? & ,its ,causes1 ,geogr4 ,j\r41 vol4 #ac1 #ahii1 pp4 #bbe-bea 7! be/ g5]al /atem5t ( ! argum5ts = a tetrah$ral =m74 ,w4 ,,pr9z4 ,l'*elle r$uite des expri5ces gologiques1 ,bull4 ,soc4 ,belge d',a/ronomie1 #ahii4 ,b4 ,k4 ,,em]son4 ,! ,tetrah$ral ,e>? & ,zone ( ! ,int]cont95tal ,seas1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #aa1 #aiaa1 pp4 #fa-ajf1 pls4 #i-ad4 ,m4 ,p4 ,,rudski4 ,physik d] ,erde 7,tau*nitz1 ,leipzig1 #aiaa71 ,*apt]s #a-c 7! be/ discussion ( ! geoid f ! purely ma!matical /&po9t1 s f> z ! sph]oid is conc]n$74 ,! e>li] figures ( ! e>?3-- ,,?4 ,,arldt4 ,die ,entwicklung d] ,kont95te und ihr] ,lebewelt4 ,engelmann1 ,leipzig1 #aijg4 7,conta9s a valuable s]ies ( map plates1 %[+ ! probable b\nd>ies ( ! cont95ts 9 ! diff]5t geological p]iods74 ,,*apt] ,,iii ,,! ,,nature ,,( ,,! ,,mat]ials ,,9 ,,! ,,li?osph]e ,! rigid quality ( our planet4--,= a long "t x 0 suppos$ t ! solid e>? con/itut$ a cru/ only :i* 0 float$ ^u a liquid int]ior4 ,?is notion 0 cle>ly an outgr[? ( ! !n g5]ally accept$ ,laplacian hypo!sis ( ! orig9 ( ! univ]se1 :i* assum$ fluid int]iors = ! planets1 ! cru/ be+ sugge/$ by ! w9t] cru/ ( froz5 wat] ^u ! surface ( our inl& lakes4 ,to-day ! nebul> hypo!sis 9 ! ,laplacian =m is fa/ giv+ place to q diff]5t conceptions1 9 :i* solid p>ticles1 & n gase\s ones1 are conceiv$ to h built up ! li?osph]e4 ,! analogy ) froz5 wat] has likewise be5 ab&on$ ) ! discov]y t froz5 rock1 in/ead ( float+1 s9ks 9 its molt5 equival5t4 ,yet ev5 m cog5t argum5ts h be5 br\ght =w>d to %[ t :atev] may be ! /ate ( aggregation )9 ! e>?'s core--& x may be diff]5t f any n[ kn[n to u--x nev]!less has _m ( ! prop]ties recogniz$ z belong+ to solid & rigid bodies4 ,provisionally1 !re=e1 we may reg>d ! e>?'s core z rigid & ess5tially solid4 ,x 0 long ago po9t$ out by ! late ,"l ,kelv9 t if our li?osph]e 7 n m rigid ?an a ball ( glass ( ! same size1 x w\ld be con/antly pass+ ?r\gh p]iodic six-h\rly di/ortions ( great amplitude 9 response to ! v>y+ attractions ( ! moon4 ,an equally /rik+ argum5t emanat+ f ! same high au?ority is furni%$ by ! well-kn[n egg-sp9n+ demon/ration4 ,= illu/ration1 ,kelv9 0 accu/om$ to take two eggs1 "o boil$ & ! o!r raw1 & attempt to sp9 !m ^u _! ends4 ,= ! boil$1 & ess5tially solid1 egg ?is is easily accompli%$1 b int]nal friction ( ! liquid cont5ts ( ! raw egg quickly /ops any rot>y motion :i* is imp>t$ to x4 ,^u ! same gr\nds x is argu$ t _h ! e>?'s int]ior possess$ ! prop]ties ( a liquid1 rotation mu/ long s9ce h ceas$4 ,a /rong] pro( ( e>? rigidity ?an ei!r ( ^! has be5 lately furni%$ by ! in/rum5tal /udy ( e>?quakes4 ,) ! delicate app>atus :i* is n[ in/all$ = ! purpose1 heavy e>?quakes may be s5s$ :i* h occurr$ any:]e ^u ! e>?'s surface1 ! e>? movem5t s5d+ its own message by ! %orte/ r\te ?r\gh ! core ( ! e>? to ! obs]v+ /ation4 ,a heavy %ock :i* occurs 9 ,new ,zeal& is record$ 9 ,engl&1 almo/ diametrically opposite1 9 ab\t tw5ty-"o m9utes aft] its occurr5ce4 ,! laws ( wave propagation & _! relation to ! prop]ties ( ! transmitt+ m$ium are well kn[n1 & 9 ord] to expla9 su* extraord9>y velocity x is necess>y to assume t = su* impulses ! e>?'s int]ior is mu* m rigid ?an ! f9e/ tool /eel4 ,probable composition ( ! e>?'s core4--,9 d]iv+ views conc]n+ ! nature ( ! e>?'s int]ior we are greatly aid$ by a/ronomical /udies4 ,! common orig9 long ago indicat$ = ! planets ( ! sol> sy/em & ! sun has be5 confirm$ by ! analysis ( light ) ! aid ( ! spectroscope4 ,x has ?us be5 f\nd t ! same *emical elem5ts :i* we f9d 9 ! e>? are pres5t also 9 ! sun & 9 ! o!r /ell> bodies4 ,aga91 ! gr\p ( planets ( ! sol> sy/em :i* are ne>e/ to ! sun--,m]cury1 ,v5us1 ! ,e>?1 & ,m>s--h ea* a high d5sity1 all except ,m>s1 ! mo/ di/ant1 hav+ specific gravities v closely #e1 t ( ,m>s be+ ab\t #d4 ,?is av]age specific gravity is also t ( ! solid bodies1 ! s-call$ meteorites1 :i* rea* ! surface ( our planet f ! surr\nd+ space4 ,yet ?\gh ! e>? z a :ole is ?us f\nd to h a specific gravity five & a half times t ( wat]1 its surface %ell has an av]age d5sity ( less ?an half ?is value1 or #b4g4 ,! /udy ( meteorites has giv5 u a possible clew to ! nature ( ! e>?'s int]ior2 = :5 bo? t]re/rial & cele/ial rock types are classifi$ & plac$ 9 ord]ly arrangem5t1 x is f\nd t ! *emical elem5ts :i* compose ! two gr\ps are id5tical1 & t ^! are unit$ accord+ to ! same physical & *emical laws4 ,no new elem5t has be5 discov]$ 9 ! "o gr\p t has n be5 f\nd 9 ! o!r1 & ?\gh "s comp\nds ( ^! elem5ts1 ! m9]als1 occur 9 ! e>?'s cru/ t h n be5 f\nd 9 meteorites1 & ?\gh "s occur 9 meteorites :i* are n kn[n f ! e>?1 yet ( ^? :i* are common to bo? bodies !re is agreem5t1 ev5 to ! m9or details 7,fig4 #i74 ,x is f\nd1 h[ev]1 t ! commone/ ( ! m9]als 9 ! e>?'s %ell are abs5t f meteorites1 z ! common] con/itu5ts ( meteorites are want+ 9 ! e>?'s cru/4 ,?is obs]vation w\ld g f> to %[ t we may 9 ! two cases be exam9+ diff]5t portions ( q simil> bodies2 & ?is view is /rik+ly confirm$ :5 ! rocks ( ! two gr\ps are arrang$ 9 ! ord] ( _! d5sities 7,fig4 #i74 ,illu/ration3 ,,fig4 #i4--;,diagram to %[ h[ t]re/rial rocks grade into ^? ( ! meteorites4 #a1 oxyg52 #b1 silicon2 #c1 alum9ium2 #d1 alkali metals2 #e1 alkal9e e>? metals2 #f1 iron1 nickel1 cobalt1 etc42 a1 granites & rhyolites2 b1 sy5ites & tra*ytes2 c1 diorites & &esites2 d1 gabbros & basalts2 e1 ultra-basic rocks2 f1 basic inclosures 9 basalt1 etc42 g1 iron basalts ( we/ ,gre5l&2 h1 iron masses ( ,ovifak1 we/ ,gre5l&2 a'-d'1 meteorites 9 ord] ( d5sity 7aft] ,judd74 ,9 a broad way1 d5sity1 /ructure1 & *emical composition are all simil>ly involv$ 9 ! gradations illu/rat$ by ! diagram2 & x is significant t :ile !re are t]re/rial rocks n repres5t$ by meteorites1 ! d5se/ & ! mo/ unusual ( ! t]re/rial rocks are *emically almo/ id5tical ) ! less d5se ( ! cele/ial bodies4 ,! e>? a magnet4--,! d5s]1 & likewise ! m common1 ( ! meteorite rocks--! s-call$ meteoric irons--are compos$ almo/ entirely ( ! elem5ts iron1 nickel1 & cobalt4 ,su* aggregates are n kn[n z yet f t]re/rial s\rces1 al?\gh transitional types appe> to exi/ ^u ! isl& ( ,disco (f ! we/ coa/ ( ,gre5l&4 ,if x 7 possible to explore ! e>?'s int]ior1 w\ld su* comb9ations ( ! iron m9]als be enc\nt]$8 ,ap>t f ! surpris+ velocity ( transmission ( e>?quake waves1 ! /ronge/ argum5t = an iron core to ! li?osph]e is f\nd 9 ! magnetic prop]ty ( ! e>? z a :ole4 ,! only magnetic elem5ts kn[n to u are ^? ( ! heavy meteorites--iron1 nickel1 & cobalt1--& ! e>? is1 z we "k1 a great magnet ^: nor!rn pole 9 ,briti% ,am]ica & ^: s\!rn pole 9 ,ant>ctica h at la/ be5 visit$ by ,amunds5 & ,david1 respectively4 ,! specific gravity ( iron is #g4ae1 & ^? ( nickel & cobalt1 :i* 9 ! meteorites are pres5t 9 relatively small am\nts1 are #g4h & #g4e1 respectively4 ,consid]+ t ! surface %ell ( ! e>? has a specific gravity ( #b4g1 ^! values mu/ be reg>d$ z agree+ well ) ! det]m9$ d5sity ( ! e>? 7#e4f7 & ! o!r planets ( its gr\p 7,m]cury #e4g1 ,v5us #e4d1 ,m>s #d74 ,! *emical con/itution ( ! e>?'s surface %ell4--,! numb] ( ! s-call$ *emical elem5ts :i* ent] into ! e>?'s composition is m ?an eighty1 b few ( ^! figure z important con/itu5ts ( ! portion kn[n to u4 ,ne>ly "o half ( ! mass ( ?is %ell is oxyg51 & m ?an a qu>t] is silicon4 ,! rema9+ qu>t] is l>gely made up ( alum9ium1 iron1 calcium1 magnesium1 & ! alkalies sodium & potassium1 9 ! ord] nam$4 ,^! eight con/itu5t elem5ts are ?us ! only ones :i* play any important rle 9 ! composition ( ! e>?'s surface %ell4 ,!y are n f\nd !re 9 ! free condition1 b comb9$ 9 ! def9ite proportions *>act]i/ic ( *emical comp\nds1 & z su* !y are kn[n z m9]als4 ,! ess5tial nature ( cry/als4--,a cry/al we are accu/om$ to ?9k ( z some?+ transp>5t b\nd$ by %>p edges & angles1 our ideas hav+ be5 obta9$ l>gely f ! gem m9]als4 ,?is outw>d symmetry ( =m is1 h[ev]1 b an expression ( a p[] :i* resides1 s to speak1 9 ! he>t or s\l ( ! cry/al individual--x has its own /ructural make-up1 its individuality4 ,no m correct e/imates ( ! comp>ison ( cry/al individualities w\ld be obta9$ by ! /udy ( outw>d =ms alone ( two m9]als ?an w\ld be ga9$ by a judgm5t ( p]sons f ! cut ( _! clo?+4 ,too (t5 ?is outw>d dress tells only ( ! conditions by :i* bo? m5 & cry/als h be5 surr\nd$1 & b little ( ! p[] inh]5t 9 ! individual4 ,_m a batt]$ m9]al fragm5t ) little beauty to recomm5d x1 :5 plac$ "u suitable conditions = its developm5t1 has gr[n into a m>vel ( beauty4 ,few m9]als are s mean t !y h n )9 !m ?is inh]5t p[] ( individuality :i* lifts !m above ! _w ( ! amorph\s & %apeless4 ,illu/ration3 ,,fig4 #aj4--;,comp>ison ( a cry/all9e ) an amorph\s sub/ance :5 exp&$ by heat & :5 attack$ by acid4 ,j z ! real nature ( a p]son is fir/ disclos$ by 8 behavior "u try+ circum/ances1 s ( a cry/al x is its conduct "u /ress ( "o sort or ano!r :i* br+s out its real "*4 ,by way ( illu/ration let u prep>e a sph]e f ! m9]al qu>tz--x matt]s n :e!r we de/roy ! beautiful outl9es ( ! cry/al or employ a batt]$ fragm5t--& !n prep>e a sph]e ( simil> size & %ape f a noncry/all9e or amorph\s sub/ance l glass4 ,if n[ ^! two sph]es be introduc$ into a ba? ( oil & rais$ to a high] temp]ature1 ! glass globe und]goes an enl>gem5t )\t *ange ( its =m2 b ! cry/al ball reveals its individuality by exp&+ into a sph]oid 9 :i* ea* new dim5sion is nicely adju/$ to ?is m complex figure 7,fig4 #aj74 ,we may1 in/ead ( submitt+ ! two balls to ! 8trial by fire01 all[ ea* to be attack$ by ! p[]ful reag5t1 hydr(luoric acid4 ,! common glass "u ! attack ( ! acid rema9s z x 0 be=e1 a sph]e1 b ) %runk5 dim5sions4 ,! cry/al1 on ! o!r h&1 is able to control ! action ( ! solv5t1 & 9 s do+ its individuality is aga9 reveal$ 9 a beautifully et*$ figure hav+ _m curv+ outl9es--x is z ?\gh ! cry/al _h possess$ a s\l :i* "u ?is trial has be5 reveal$4 ,?is glimpse into ! nature ( ! cry/al1 s z to reveal its /ructural beauty1 is /ill m surpris+ :5 ! cry/al is tak5 f ! acid 9 ! e>ly /ages ( ! action & held close b5ea? ! eye4 ,n[ ! little et*+s ^u ! surface display ea* ! individuality ( ! sub/ance1 & jo9+ ) _! neighbors !y s5d out a beautifully symmetrical & entirely *>act]i/ic picture 7,fig4 #aa74 ,illu/ration3 ,,fig4 #aa4--8,light figure0 se5 ^u an et*$ surface ( a cry/al ( calcite 7aft] ,golds*midt & ,wright74 ,! li?osph]e a complex ( int]lock+ cry/als4--,to ! layman ! cry/al is some?+ r>e & exp5sive1 to be obta9$ f a jewel] or to be se5 display$ 9 ! %[ cases ( ! great museums4 ,yet ! "o mo/ /rik+ quality ( ! li?osph]e :i* sep>ates x f ! hydrosph]e & ! atmosph]e is its cry/all9e /ructure1--a /ructure belong+ also to ! meteorite1 & ) little d\bt to all ! planets ( ! e>? gr\p4 ,a sn[flake caught dur+ its fall f ! sky reveals all ! delicate trac]y ( cry/al b\nd>y2 collect$ f a ?ick lay] ly+ ^u ! gr\nd1 x appe>s z an intricate aggregate ( brok5 fragm5ts m or less firmly cem5t$ toge!r4 ,& s x is ( ! li?osph]e1 = ! myriads ( individuals are ei!r ! ru9s ( =m] cry/als1 or !y are gr[n toge!r 9 su* a mann] t cry/al facets _h no opportunity to develop4 ,su* m9]al individuals z once possess$ ! cry/al =m may h be5 brok5 & _! surfaces gr\nd away by mutual attrition "u ! rhy?mic beat+ ( ! waves ^u a %ore or 9 ! cont9u\s roll+ ( pebbles on a /ream b$1 until z batt]$ relics !y are pil$ away toge!r 9 a b$ ( s&4 ,yet no am\nt ( su* r\gh h&l+ is suffici5t to de/roy ! cry/al individuality1 & if !y are n[ surr\nd$ ) conditions :i* are suitable = _! gr[?1 _! individual nature aga9 becomes reveal$ 9 new cry/al outl9es4 ,_m ( our s&/ones :5 turn$ 9 ! bright sunlight s5d out fla%es ( light to rival a bank ( sn[ 9 e>ly spr+4 ,^! bright fla%es proce$ f ! facets ( m9ute cry/als =m$ ab\t ea* r\nd$ gra9 ( ! s&1 & if we exam9e !m "u a l5s1 we may note ! beauty ( l9e =m$ ) su* exactness t ! mo/ delicate in/rum5ts c detect no diff]5ce betwe5 ! simil> angles ( neighbor+ cry/als 7,fig4 #ab74 ,illu/ration3 ,,fig4 #ab4--;,batt]$ s& gra9s :i* h tak5 on a new lease ( life & h develop$ a cry/al =m4 a1 a s+le gra9 gr[n into an individual cry/al2 b1 a p>allel gr[? ab\t a s+le gra92 c1 gr[? ( neighbor+ gra9s until !y h mutually int]f]$ & s de/roy$ ! cry/al facets--! common condition )9 ! mass ( a rock 7aft] ,irv+ & ,van ,hise74 ,?is individual nature ( ! cry/al is believ$ to reside 9 a symmetrical gr\p+ ( ! *emical molecules ( ! sub/ance into l>g] & s-call$ 8cry/al molecules40 ,! cry/al quality belongs to ! *emical elem5ts & to _! comp\nds 9 ! solid condition1 b n to ord9>y mixtures ( !m4 ,"s prop]ties ( natural cry/als1 m9]als4--,no two m9]al species appe> 9 cry/als ( ! same appe>ance1 any m ?an two animal species h be5 giv5 ! same =m2 & s m9]als may be recogniz$ by ! individual peculi>ities ( _! cry/als4 ,yet = ! reason t cry/als h s g5]ally be5 prev5t$ f develop+ or reta9+ _! *>act]i/ic faces1 9 ! va/ numb] ( in/ances x is ! behavior1 & n ! appe>ance1 ( ! m9]al sub/ance :i* is made use ( = id5tification4 ,:5 a m9]al is brok5 "u ! bl[ ( a hamm]1 in/ead ( yield+ an irregul> fracture1 l t ( glass1 x g5]ally t5ds to "p along "o or m directions s z to leave plane surfaces4 ,?is prop]ty ( cleavage is /rik+ly illu/rat$ = a s+le direction 9 ! m9]al mica1 = two directions 9 feldsp>1 & = ?ree directions 9 calcite or ,icel& sp>4 ,o!r prop]ties ( m9]als1 su* z h>dness1 specific gravity1 lu/]1 color1 fusibility1 etc41 are all made use ( 9 r\gh det]m9ations ( ! m9]als4 ,f> m delicate me?ods dep5d ^u ! behavior ( m9]als :5 obs]v$ 9 pol>iz$ light1 & su* behavior is ! basis ( ^? bran*es ( geological sci5ce kn[n z optical m9]alogy & z microscopical petrography4 ,an outl9e description ( "s ( ! common m9]als & ! means = id5tify+ !m w be f\nd 9 app5dix ,a4 ,! alt]ations ( m9]als4--,by f> ! l>g] numb] ( m9]als h be5 =m$ 9 ! cool+ & consequ5t consolidation ( molt5 rock mat]ial su* z dur+ a volcanic eruption rea*es ! e>?'s surface z lava4 ,beg9n+ _! gr[? at _m po9ts )9 ! visc\s mass1 ! individual cry/als ev5tually may gr[ toge!r & s prev5t a developm5t ( _! cry/al faces4 ,ano!r class ( m9]als are deposit$ f solution 9 wat] )9 ! cavities & fissures ( ! rocks2 & if ?is process ceases be=e ! cavities h be5 completely clos$1 ! m9]als are f\nd project+ f ! walls 9 a beautiful l9+ ( cry/al--! ,kry/allkell] or 8cry/al cell>40 ,x is f su* pockets or ve9s )9 ! rocks t ! valuable ores are obta9$1 z are ! cry/als :i* are display$ 9 our m9]al cab9ets4 ,illu/ration3 ,,fig4 #ac4--;,cry/al ( g>net develop$ 9 a s*i/ ) gra9s ( qu>tz includ$ because n assimilat$4 ,!re is1 h[ev]1 a ?ird process by :i* m9]als are =m$1 & m9]als ( ?is class are produc$ )9 ! solid rock z a product ( ! alt]ation ( prexi/+ m9]als4 ,"u ! enorm\s pressures ( ! rocks deep bel[ ! e>?'s surface1 !y are z p]meable to ! p]colat+ wat]s z is a sponge at ! surface4 ,"u ^! conditions c]ta9 m9]als are dissolv$ & _! mat]ial r$eposit$ aft] travel+ 9 ! solution1 or solution & r$eposition ( m9]al matt] may g on toge!r )9 ! mass ( ! same rock4 ,"o new m9]al may h be5 produc$ f ! dissolv$ mat]ials ( a numb] ( e>li] species1 or sev]al new m9]als may be ! result ( ! alt]ation ( a prexi/+ m9]al ) a m complex *emical /ructure4 ,:]e ! new m9]al has be5 =m$ 89 place01 x has sometimes be5 able to utilize ! mat]ials ( all ! m9]als :i* be=e exi/$ !re1 or x may h be5 oblig$ to inclose )9 itself ^? e>li] con/itu5ts :i* x c\ld n assimilate 9 its own /ructure 7,fig4 #ac74 ,illu/ration3 ,,fig4 #ad4--;,a cry/al ( augite )9 ! mass ( a rock alt]$ 9 "p to =m a rim ( ! m9]als hornbl5de & magnetite4 ,note ! orig9al outl9e ( ! augite cry/al4 ,at o!r times a cry/al :i* is imb$d$ 9 rock has be5 attack$ ^u its surface by ! p]colat+ solutions1 & ! dissolv$ mat]ials h be5 deposit$ 9 place z a cr[n ( new m9]als :i* /eadily wid5s its zone until ! c5t] is rea*$ & ! orig9al cry/al has be5 entirely trans=m$ 7,fig4 #ad74 ,x is sometimes possible to say t ! action by :i* ^! *anges h be5 br\ght ab\t has involv$ a nice adju/m5t ( supply ( ! *emical con/itu5ts necess>y to ! =mation ( ! new m9]al or m9]als4 ,9 rocks :i* are aggregates ( sev]al m9]al species1 a newly =m$ m9]al may appe> only at ! common m>g9 ( c]ta9 ( ^! species1 ?us %[+ t !y supply ^? *emical elem5ts :i* 7 necess>y to ! =mation ( ! new sub/ance 7,fig4 #ae74 ,?us x is se5 t bel[ ! e>?'s surface *emical reactions are con/antly go+ on1 & ! e>li] rocks are ?us locally be+ trans=m$ into o!rs ( a diff]5t m9]al con/itution4 ,illu/ration3 ,,fig4 #ae4--;,a new m9]al 7hornbl5de7 =m+ z an int]m$iate 8reaction rim0 betwe5 ! m9]al hav+ irregul> fractures 7oliv9e7 & ! du/y :ite m9]al 7lime-soda feldsp>74 ,ne> ! e>?'s surface ! c>bon dioxide & ! moi/ure :i* are pres5t 9 ! atmosph]e are con/antly *ang+ ! expos$ portions ( ! li?osph]e into c>bonates1 hydrates1 & oxides4 ,^! comp\nds are m soluble ?an are ! m9]als out ( :i* !y 7 =m$1 & !y are also m bulky & s t5d to crack (f f ! p>5t mass on :i* !y 7 =m$4 ,z we are to see1 = bo? ( ^! reasons ! surface rocks ( ! li?osph]e succumb to ?is attack f ! atmosph]e4 ,9 connection ) ^? wr9kl+s ( ! surface %ell ( ! li?osph]e f :i* m\nta9s result1 ! und]ly+ rocks are subject$ to great /ra9s1 & ev5 :]e no visible p>t+s are produc$1 ! rocks are de=m$ s t individual m9]als may be b5t into cresc5t-%ap$ or ,s-%ap$ =ms1 or !y are p>t$ into "o or m fragm5ts :i* rema9 imb$d$ )9 ! rock4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,iii ,!ories ( orig9 ( ! e>?3-- ,,?omson & ,,tait4 ,natural ,philosophy4 #b;d ed4 ,cambridge1 #ahhc1 pp4 #dbb4 ,t4 ,c4 ,,*amb]l94 ,*amb]l9 & ,salisbury's ,geology1 vol4 #b1 pp4 #a-ha4 ,rigidity ( ! e>?3-- ,,"l ,,kelv94 ,! ,int]nal ,condition ( ! ,e>? z to ,temp]ature1 ,fluidity1 & ,rigidity1 ,popul> ,lectures & ,addresses1 vol4 #b1 pp4 #bii-cah2 ,review ( evid5ce reg>d+ ! physical condition ( ! e>?1 ibid41 pp4 #bch-bgb4 ,,hobbs4 ,e>?quakes 7,appleton1 ,new ,york1 #aijg71 ,*apt]s xvi & xvii4 ,composition ( ! e>?'s core & %ell3-- ,o4 ,c4 ,,f>r+ton4 ,! ,pret]re/rial ,hi/ory ( ,meteorites1 ,j\r4 ,geol41 vol4 #i1 #aija1 pp4 #fbc-bcf4 ,e4 ,s4 ,,dana4 ,m9]als & ,h[ to ,/udy ,!m 7a book = beg9n]s 9 m9]alogy74 ,wiley1 ,new ,york1 #ahie4 ,on ! nature ( cry/als3-- ,,victor ,,golds*midt4 ,ueb] das ,wes5 d] ,kry/alle1 ,o/walds ,annal5 d] ,naturphilosophie1 vol4 #i1 #aiji-aiaj1 pp4 #abj-aci1 #cfh-dai4 ,,*apt] ,,iv ,,! ,,rocks ,,( ,,! ,,e>?',s ,,surface ,,%ell ,! processes by :i* rocks are =m$4--,rocks may be =m$ 9 any "o ( sev]al ways4 ,:5 a portion ( ! molt5 li?osph]e1 s-call$ magma1 cools & consolidates1 ! product is igne\s rock4 ,ei!r igne\s or o!r rock may become dis9tegrat$ at ! e>?'s surface1 & aft] m or less ext5d$ travel1 ei!r 9 ! air1 9 wat]1 or 9 ice1 be laid d[n z a s$im5t4 ,su* s$im5ts1 :e!r cem5t$ into a coh]5t mass or n1 are describ$ z s$im5t>y or cla/ic rocks4 ,if ! fluid f :i* !y 7 deposit$ 0 ! atmosph]e1 !y are kn[n z subarial or eolian s$im5ts2 b if wat]1 !y are kn[n z subaque\s deposits4 ,/ill ano!r class are ice-deposit$ & are kn[n z glacial deposits4 ,illu/ration3 ,,fig4 #af4--,lam9at$ /ructure ( s$im5t>y rock1 ,we/]n ,kansas 7aft] a photograph by ,e4 ,s4 ,tuck]74 ,b1 z we h le>n$1 rocks may und]go trans=mations ?r\gh m9]al alt]ation1 9 :i* case !y are kn[n z metamorphic rocks4 ,:5 ^! *anges consi/ *iefly 9 ! production ( m soluble m9]als at ! surface1 accompani$ by ?or\gh dis9tegration1 due to ! direct attack ( ! atmosph]e1 ! result+ rocks are call$ residual rocks4 ,! m>ks ( orig94--,ea* ( ! ?ree great classes ( rocks1 ! igne\s1 s$im5t>y1 & metamorphic1 is *>act]iz$ by bo? co>s] & f9] /ructures1 9 ! exam9ation ( :i* !y may be id5tifi$4 ,! igne\s rocks hav+ be5 produc$ f magmas1 :i* are ess5tially homog5e\s1 are usually )\t def9ite directional /ructures due to an arrangem5t ( _! con/itu5ts1 & are said to h a massive /ructure4 ,s$im5t>y rocks1 ^u ! o!r h&1 h be5 =m$ by an assort+ process1 ! l>g] & heavi] fragm5ts hav+ be5 laid d[n :5 !re 0 high velocity ( ei!r w9d or wat] curr5t1 & ! small] & light] fragm5ts dur+ int]m$iate p]iods4 ,!y are !re=e m or less b&$1 & are said to h a b$d$ or lam9at$ /ructure 7,fig4 #af74 ,aga91 igne\s rocks1 be+ due to a process ( cry/allization1 are compos$ ( m9]al individuals :i* are b\nd$ ei!r by cry/al planes or by irregul> surfaces along :i* neighbor+ cry/als h int]f]$ ) ea* o!r2 b 9 ei!r case ! gra9s possess %>ply angul> b\nd>ies4 ,q diff]5t has be5 ! result ( ! attrition betwe5 gra9s 9 ! transportation & deposition ( s$im5ts1 = x is *>act]i/ic ( ! s$im5t>y rocks t _! con/itu5t gra9s are well r\nd$4 ,eolian s$im5ts h usually m p]fectly r\nd$ gra9s ?an subaque\s deposits4 ,glacial deposits1 if laid d[n directly by ! ice1 are un/ratifi$1 relatively co>se1 & conta9 pebbles :i* are bo? facet$ & /riat$4 ,su* deposits are describ$ z till or tillite4 ,if glaci]-d]iv$ mat]ial is tak5 up by ! /reams ( ?aw wat] & is by !m r$eposit$1 ! s$im5ts are assort$ or /ratifi$1 & !y are describ$ z fluvio-glacial deposits4 ,! metamorphic rocks4--,bo? ! co>s] /ructures & ! f9] textures ( ! metamorphic rocks are int]m$iate betwe5 ^? ( ! igne\s & ! s$im5t>y classes4 ,a metamorphos$ s$im5t>y rock1 9 proportion to its alt]ation1 loses ! p]fect lam9ation & ! r\nd$ gra9 :i* 7 its di/+ui%+ *>act]s2 :ile an igne\s rock takes on 9 ! process an imp]fect b&+1 & ! %>p angles ( its con/itu5t gra9s become r\nd$ (f by a sort ( p]iph]al cru%+ or granulation4 ,metamorphic rocks are !re=e *>act]iz$ by an imp]fectly b&$ /ructure describ$ z s*i/osity or gneiss b&+1 & ! con/itu5t gra9s may be ei!r angul> or r\nd$4 ,if ! metamorphism has n be5 too int5se or too long cont9u$1 x is g5]ally possible to det]m9e1 p>ticul>ly ) ! aid ( ! pol>iz+ microscope1 :e!r ! orig9al rock f :i* x 0 d]iv$ 0 ( igne\s or ( s$im5t>y orig94 ,!re are1 h[ev]1 _m examples :i* h defi$ a reliable v]dict conc]n+ _! orig94 ,*>act]i/ic textures ( ! igne\s rocks4--,9 addition to ! massiv5ess ( _! g5]al aspect & ! angul> b\nd>ies ( _! con/itu5ts1 !re are _m additional textures :i* are *>act]i/ic ( ! igne\s rocks4 ,:ile ^? t h consolidat$ bel[ ! e>?'s surface1 ! intrusive rocks1 are notably compact1 ! magmas :i* arrive at ! surface ( ! li?osph]e be=e _! consolidation reveal special /ructures dep5d5t ei!r ^u ! expansion ( /eam & o!r gases )9 !m1 or ^u ! conditions ( fl[ ov] ! e>?'s surface4 ,magmas :i* ?us rea* ! surface ( ! e>? are describ$ z lavas1 & ! rocks produc$ by _! consolidation are extrusive or volcanic rocks4 ,! /eam includ$ 9 ! lava exp&s into bubbles or vesicles :i* may be l>ge or small1 few or _m4 ,accord+ to ! numb] & ! size ( ^! cavities1 ! rock is said to h a vesicul>1 scoriace\s1 or pumice\s texture4 ,mo/ lavas1 :5 !y arrive at ! e>?'s surface1 conta9 cry/als :i* are m or less dissem9at$ ?r\gh\t ! molt5 mass4 ,! t\ri/ :o visits ,m\nt ,vesuvius at ! "t ( a light eruption may ?ru/ 8 /aff into ! /ream ( lava & extract a portion ( ! visc\s sub/ance 9 :i* are se5 beautiful :ite cry/als ( ! m9]al leucite1 ea* b\nd$ by tw5ty-f\r cry/al faces4 ,x is cle> t ^! cry/als mu/ h develop$ by a sl[ gr[? )9 ! magma :ile x 0 /ill bel[ ! surface1 & :5 ! inclos+ lava has consolidat$1 ^! e>li] cry/als lie scatt]$ )9 a gr\ndmass ( glassy or m9utely cry/all9e mat]ial4 ,?is scatt]+ ( cry/als belong+ to an e>li] g5]ation )9 a gr\ndmass due to lat] consolidation is ?us an indication ( int]ruption 9 ! process ( cry/allization1 & ! texture :i* results is describ$ z porphyritic 7,fig4 #ag b74 ,%\ld ! lava arrive at ! surface be=e any cry/als h be5 g5]at$ & consolidate rapidly z a rock glass1 its texture is describ$ z glassy 7,fig4 #ag c74 ,:5 ! cry/als ( ! e>li] g5]ation are num]\s & ne$le-l 9 =m1 z is v (t5 ! case1 !y arrange !mselves 8end on0 dur+ ! rock fl[1 s t :5 consolidation has occurr$1 ! rock has a k9d ( puck]$ lam9ation :i* is ! *>act]i/ic ( ! fluxion or fl[ texture4 ,?is texture has sometimes be5 confus$ ) ! lam9ation ( ! s$im5t>y rocks1 s t wrong conclusions h be5 rea*$ reg>d+ orig94 ,at o!r times ! same ne$le-l cry/als )9 ! lava h gr\p$ !mselves radially to =m r\nd$ nodules call$ sph]ulites4 ,su* nodules give to ! rock a sph]ulitic texture1 :i* is n[h]e bett] display$ ?an 9 ! beautiful glassy lavas ( ,obsidian ,cliff 9 ! ,yell[/one ,national ,p>k4 ,illu/ration3 ,,fig4 #ag4--;,*>act]i/ic textures ( igne\s rocks4 a1 granitic texture *>act]i/ic ( ! deep-seat$ intrusive rocks2 b1 porphyritic texture *>act]i/ic ( ! extrusive & ( ! ne>-surface intrusive rocks2 c1 glassy texture ( an extrusive rock4 ,^? intrusive rocks :i* consolidate deep bel[ ! e>?'s surface1 "p ) _! heat b sl[ly1 & s ! process ( cry/allization is cont9u$ )\t int]ruption4 ,/>t+ f _m c5t]s1 ! cry/als cont9ue to gr[ until !y mutually int]sect 9 an int]lock+ complex kn[n z ! granitic texture 7,fig4 #ag a74 ,classification ( rocks4--,9 tabul> =m rocks may ?us be classifi$ z foll[s3-- ,intrusive4 ,granitic or porphyritic texture4 ,igne\s4 ,massive & ,extrusive4 ,glassy or porphyritic ) %>ply angul> texture2 (t5 also ) vesicul>1 gra9s4 scoriace\s1 pumice\s1 fluxion1 or sph]ulitic textures4 ,subarial4 ,s&s & loess4 ,subaque\s4 7,see bel[47 ,s$im5t>y4 ,lam9ate ,glacial4 ,co>se1 un/ratifi$ & ) r\nd$ deposits ) facet$ pebbles4 ,till gra9s4 & tillite4 ,fluvio-glacial4 ,/ratifi$ s&s & gravels ) 8work$ ov]0 glacial *>act]s4 ,metamorphic4 ,s*i/ose ,metamorphic prop]4 ,due to bel[ & ) gra9s ei!r surface *anges4 angul> or r\nd$4 ,residual4 ,dis9tegrat$ at or ne> surface4 ,subdivisions ( ! s$im5t>y rocks4--,:ile ! eolian s$im5ts are all ! product ( a purely me*anical process ( lift+1 transportation1 & deposition ( rock p>ticles1 ?is is n always ! case ) ! subaque\s s$im5ts1 s9ce wat] has ! p[] ( dissolv+ m9]al sub/ance1 z x has also ( furni%+ a home = animal & vegetable life4 ,deposit$ mat]ials :i* h be5 9 solution 9 wat] are describ$ z *emical deposits1 & ^? :i* h play$ a "p 9 ! life process z organic deposits4 ,! organic deposits f vegetable s\rces are peat & ! coals1 :ile lime/ones & m>ls are ! *ief depositories ( ! rema9s ( ! animal life ( ! wat]4 ,! tabul> classification ( ! s$im5ts is z foll[s3-- ,classification ( ,s$im5ts4 ,subaque\s ,conglom]ate1 s&/one ,deposit$ by wat]4 & %ale4 ,subarial or ,eolian ,s&/one & loess4 ,me*anical ,deposit$ by w9d4 ,glacial ,till & tillite4 ,deposit$ by ice4 ,fluvio-glacial ,s&s & gravels4 ,glaci]-wat] deposits4 ,calc>e\s tufa ,deposit$ 9 spr+s & riv]s4 ,*emical ,olitic lime/one ,deposit$ at ! m\?s ( riv]s betwe5 high & l[ tide4 ,=m$ ( plant rema9s4 ,peats & coals4 ,organic ,=m$ ( animal rema9s4 ,lime/ones & m>ls4 ,w9ds are "u favorable conditions capable ( transport+ bo? du/ & s&1 b n ! l>g] rock fragm5ts4 ,! du/ deposits are f\nd accumulat+ outside ! bord]s ( des]ts z ! s-call$ loess 7,fig4 #baf71 ?\gh ! s& is nev] c>ri$ beyond ! des]t bord]1 ne> :i* x collects 9 wide belts ( ridges describ$ z dunes4 ,:5 ?is s& has be5 cem5t$ into a coh]5t mass1 x is kn[n z eolian s&/one4 ,a section ( ! app5dix 7,b7 is devot$ to an outl9e description ( "s ( ! common] rock types4 ,! diff]5t deposits ( ocean1 lake1 & riv]4--,( ! subaque\s s$im5ts1 !re are ?ree di/9ct types result+3 7#a7 f s$im5tation 9 riv]s1 ! fluviatile deposits2 7#b7 f s$im5tation 9 lakes1 ! lacu/r9e deposits2 & 7#c7 f s$im5tation 9 ! ocean1 m>9e deposits4 ,aga91 ! wide/ range ( "* is display$ by ! deposits :i* are laid d[n 9 ! diff]5t p>ts ( ! c\rse ( a /ream4 ,ne> ! s\rce ( a riv]1 co>se riv] gravels may be f\nd2 9 ! middle c\rse ! f9] silts2 & 9 ! m\? or delta region1 :]e ! deposits ent] ! sea or a lake1 !re is f\nd an assortm5t ( silts & clays4 ,except )9 ! delta region1 :]e ! area ( deposition beg9s to broad51 ! deposits ( riv]s are /ret*$ out 9 long & relatively n>r[ zones1 & are s di/+ui%$ f ! f> m important lacu/r9e & m>9e deposits4 ,lakes & oceans h ?is 9 common t bo? are bodies ( /&+ z contra/$ ) fl[+ wat]2 & bo? are subject to ! p]iodical rhy?mic motions & along%ore curr5ts due to ! waves rais$ by ! w9d4 ,ab\t _! m>g9s1 ! deposits ( lake & ocean are ?us 9 l>ge "p wre/$ by ! waves f ! neighbor+ l&4 ,_! di/ribution is always su* t ! co>se/ mat]ials are laid d[n ne>e/ to ! %ore1 & ! deposits become ev] f9] 9 ! direction ( deep] wat]4 ,relatively f> f %ore may be f\nd ! f9e/ s&s & muds or calc>e\s deposits1 :ile ne> ! %ore are s&s1 &1 f9ally1 along ! bea*1 b$s ( bea* pebbles or %+le4 ,:5 cem5t$ into coh]5t rocks1 ^! deposits become %ales or lime/ones1 s&/ones1 & conglom]ates1 respectively4 ,z reg>ds ! lime/ones1 _! orig9 is involv$ 9 consid]able unc]ta9ty4 ,"s1 l ! %ell lime/one or coqu9a ( ! ,florida coa/1 are an aggregation ( rema9s ( mollusks :i* live ne> ! bord] ( ! sea4 ,o!r lime/ones are deposit$ directly f c>bonate ( lime 9 solution 9 ! wat]4 ,a deposit ( ?is nature is =m+ 9 s\!rn ,florida1 bo? z a floccul5t calc>e\s mud & z cry/als ( lime c>bonate ^u a lime/one surface4 ,aga91 !re is ! reef lime/one :i* is built up ( ! /ony p>ts ( ! coral animal1 &1 la/ly1 ! calc>e\s ooze ( ! deep-sea deposits4 ,! m>9e s$im5ts :i* are d]iv$ f ! cont95ts1 ! s-call$ t]rig5\s deposits1 are f\nd only ^u ! cont95tal %elf & ^u ! cont95tal slope j outside x4 ,( ^! t]rig5\s deposits1 x is cu/om>y to di/+ui%3 7#a7 littoral or along%ore deposits1 :i* are laid d[n betwe5 high & l[ tide levels2 7#b7 %oal wat] deposits1 :i* are f\nd betwe5 l[-wat] m>k & ! edge ( ! cont95tal %elf2 & 7#c7 aktian or (f%ore deposits1 :i* are f\nd ^u ! cont95tal slope4 ,! littoral & %oal wat] deposits are ma9ly gravels & s&s1 :ile ! (f%ore deposits are pr9cipally muds or lime deposits4 ,special m>ks ( littoral deposits4--,! m>ks ( ripples are (t5 left 9 ! s& ( a bea*1 & may be pres]v$ 9 ! s&/one :i* results f ! cem5tation ( su* deposits 7pl4 #aa ,a74 ,v simil> m>k+s are1 h[ev]1 q *>act]i/ic ( ! surface ( w9d-bl[n s&4 ,= ! reason t deposits are subject to _m vicissitudes 9 _! subsequ5t hi/ory1 s t !y sometimes /& at /eep angles or are ev5 ov]turn$1 x is important to obs]ve ! curves ( s& ripples s z to di/+ui% ! upp] f ! l[] surface4 ,9 ! f9] s&s & muds ( %elt]$ tidal flats may be pres]v$ ! impressions f ra9drops or ( ! feet ( animals :i* h w&]$ ov] ! flat dur+ an ebb tide4 ,:5 ! tide is at flood1 new mat]ial is laid d[n ^u ! surface & ! impressions are fill$1 b ?\gh h>d5$ into rock1 ^! surfaces are ^? ^u :i* ! rock is easily p>t$1 & s ! impressions are pres]v$4 ,9 ! s&/ones ( ! ,connecticut valley !re has be5 pres]v$ a q rem>kable record 9 ! footpr9ts ( animals belong+ to ext9ct species1 :i* at ! "t ^! deposits 7 laid d[n mu/ h be5 abundant ^u ! neighbor+ %ores4 ,betwe5 ! tides muds may dry out & crack 9 int]sect+ l9es l ! walls ( a honeycomb1 & :5 ! cracks h be5 fill$ at high tide1 a /ructure is produc$ :i* may lat] be recogniz$ & is usually ref]r$ to z 8mud-crack0 /ructure4 ,?is /ructure is ( special s]vice 9 di/+ui%+ m>9e deposits f ! subarial or cont95tal deposits4 ,a v>iation 9 ! direction ( w9ds ( successive /orms may be responsible = ! pil+ up ( ! bea* s& 9 a peculi> 8plunge & fl[0 or 8cross-b$d$0 /ructure1 a /ructure :i* is extremely common 9 littoral deposits1 ?\gh simulat$ 9 rocks ( eolian orig94 ,! ord] ( deposition dur+ a transgression ( ! sea4--,_m %ore l9es ( ! cont95ts are almo/ con/antly migrat+ ei!r l&w>d or seaw>d4 ,:5 ! %ore l9e advances ov] ! l&1 ! coa/ is s9k+1 & m>9e deposits w be =m$ directly above :at 0 rec5tly ! 8dry l&40 ,su* an invasion ( ! l& by ! sea1 due to a subsid5ce ( ! coa/1 is call$ a transgression ( ! sea1 or simply a transgression4 ,?\gh at any mom5t ! littoral1 %oal wat]1 & (f%ore deposits are ea* be+ laid d[n 9 a p>ticul> zone1 x is evid5t t ea* mu/ advance 9 turn 9 ! direction ( ! %ore & s be deposit$ above ! zones ne>] %ore4 ,?us !re comes to be a def9ite s]ies ( cont9u\s b$s1 "o above ! o!r1 provid$ only t ! process is cont9u$ 7,fig4 #ah74 ,at ! v bottom ( ?is s]ies !re w usually be f\nd a ?9 b$ ( pebbly bea* mat]ials1 :i* lat] w h>d5 into ! s-call$ basal conglom]ate4 ,if ! size ( ! pebbles is su* z to make possible an id5tification1 x w g5]ally be f\nd t ^! repres5t ! ru9s ( ! rock ov] :i* ! sea has advanc$ ^u ! l&4 ,illu/ration3 ,,fig4 #ah4--;,diagram to %[ ! ord] ( ! s$im5ts laid d[n dur+ a transgression ( ! sea4 ,next 9 ord] above ! basal conglom]ate1 w foll[ ! co>s] & !n ! f9] s&s1 ^u :i* 9 turn w be laid d[n ! (f%ore s$im5ts--! muds & ! lime deposits4 ,lat]1 :5 cem5t$ toge!r1 ^! become 9 ord]1 co>s] & f9] s&/ones1 %ales1 & lime/ones4 ,! ord] ( sup]position1 read+ f ! bottom to ! top1 ?us gives ! ord] ( decreas+ age ( ! =mations4 ,a subsequ5t uplift ( ! coa/ w be accompani$ by a recession ( ! sea1 & :5 lat] dissect$ by nature = our inspection1 ! ord] ( sup]position & ! individual "* ( ea* ( ! deposits may be /udi$ at leisure4 ,f su* /udies x has be5 f\nd t along ) ! inorganic deposits !re are (t5 f\nd ! rema9s ( life 9 ! h>d p>ts ( su* inv]tebrate animals z ! mollusks & ! cru/acea4 ,^! s-call$ fossils repres5t animals :i* 7 gradually develop$ f simpl] to m & m complex =ms2 & !y ?us s]ve ! purpose ( successive page numb]s 9 arrang+ ! ord] ( di/urb$ /rata1 at ! same "t t !y supply ! mo/ secure f\ndation ^u :i* re/s ! great doctr9e ( evolution4 ,! bas9s ( e>li] ages4--,x 0 ! great ,vi5nese geologi/1 ,pr(essor ,suess1 :o fir/ po9t$ out t 9 m\nta9 regions !re are f\nd ! ?icke/ & ! mo/ complete s]ies ( ! m>9e deposits2 :]eas outside ^! prov9ces ! =mations are sep>at$ by wide gaps repres5t+ p]iods :5 no deposits 7 laid d[n because ! sea _h retir$ f ! region4 ,! complet5ess ( ! s]ies ( deposits 9 ! m\nta9 di/ricts c only be int]pret$ to mean t :]e ^! b lately =m$ m\nta9s rise to-day1 7 = long prec$+ ages ! bas9s = deposition ( t]rig5\s s$im5ts4 ,x w\ld seem t ! li?osph]e 9 its adju/m5t _h select$ ^! e>li] sea bas9s ) _! heavy lay]s ( s$im5t = zones ( special uplift4 ,! deposits ( ! deep sea4--,outside ! cont95tal slope1 ^: base m>ks ! limit ( ! t]rig5\s deposits1 lies ! deep] sea1 = ! mo/ "p a s]ies ( broad pla9s1 b v>i$ by m pr(\nd /eep-wall$ bas9s1 ! s-call$ 8deeps0 ( ! ocean4 ,z %[n by ! dr$g+s ( ! ,*all5g] exp$ition & o!rs ( m rec5t date1 ! deposits ^u ! ocean floor are ( a :olly diff]5t "* f ^? :i* are d]iv$ f ! cont95ts4 ,except 9 ! great deeps1 or betwe5 dep?s ( five hundr$ & fifte5 hundr$ fa?oms1 ^! deposits are ! s-call$ 8ooze01 compos$ ( ! calc>e\s or *it9\s p>ts ( alg & ( m9ute animal organisms4 ,! pelagic or surface wat]s ( ! ocean are1 z x 71 a great mead[ ( ^! plant =ms1 ^u :i* ! m9ute cru/acea1 su* z globig]9a1 =am9if]a1 & ! pt]opods1 fe$ 9 c\ntless myriads4 ,! h>d p>ts ( bo? plant & animal organisms desc5d to ! bottom & !re =m ! ooze 9 :i* are sometimes f\nd ! e> bones ( :ales & ! tee? ( %>ks4 ,9 ! deeps ( ! ocean1 none ( ^! vegetable or animal deposits are be+ laid d[n1 b only ! s-call$ 8r$ clay01 :i* is believ$ to repres5t decompos$ volcanic mat]ial deposit$ by ! w9ds z f9e du/ on ! surface ( ! ocean1 or ! product ( subm>9e volcanic eruption4 ,f ! abs5ce ( ! ooze 9 ^! pr(\nd dep?s1 ! conclusion is =c$ ^u u t ! h>d p>ts ( ! m9ute organisms are dissolv$ :ile fall+ ?r\gh ?ree or f\r miles ( ! ocean wat]4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,iv ,j4 ,s4 ,,dill]4 ,! ,educational ,s]ies ( ,rock ,specim5s collect$ & di/ribut$ by ! ,unit$ ,/ates ,geological ,survey1 ,bull4 #aej ,u4 ,s4 ,geol4 ,surv41 #ahih1 pp4 #a-djj4 ,l4 ,v4 ,,pirsson4 ,rocks & ,rock ,m9]als4 ,wiley1 ,new ,york1 #aijh4 ,,sir ,,john ,,murray4 ,deep-sea ,deposits1 ,reports ( ! ,*all5g] exp$ition1 ,*apt] iii4 ,l4 ,w4 ,,collet4 ,les dpts m>9s4 ,do91 ,p>is1 #aijg 7,encyclopdie ,sci5tifique74 ,,*apt] ,v ,,contortions ,,( ,,! ,,/rata ,,)9 ,,! ,,zone ,,( ,,fl[ ,! zones ( fracture & fl[4--,x is easy to ?9k ( ! atmosph]e & ! hydrosph]e z ea* su/a9+ at any po9t ! load ( ! sup]9cumb5t mat]ial4 ,at ! sea level ! weight ( air ^u ea* squ>e in* ( surface is ab\t fifte5 p\nds1 :]eas ^u ! floor ( ! hydrosph]e 9 ! m pr(\nd deeps ! load ^u ! squ>e in* mu/ be measur$ 9 tons4 ,ne> ! li?osph]e surface ! rocks support by _! /r5g? ! load ( rock above !m1 b at great] dep?s !y are unable to d ?is1 = ! load be>s ^u ea* portion ( ! rock ) a pressure equival5t to ! weight ( a rock column :i* ext5ds upw>d to ! surface4 ,! av]age specific gravity ( rock is #b4g1 & x is ?us easy to calculate ! l5g? ( ! in* squ>e column :i* has a weight equival5t to ! cru%+ /r5g? ( any giv5 rock4 ,at ! dep? repres5t$ by ! l5g? ( su* a column1 rocks _c yield to pressure by fracture1 = ! op5+ ( a crack implies t ! rock ^u ei!r side is /rong en\gh to prev5t ! walls f clos+4 ,at ?is dep?1 rock mu/ !re=e yield to pressure n by fracture1 z x w\ld at ! surface1 b by fl[ aft] ! mann] ( a liquid2 & s ! zone bel[ ?is critical level is ref]r$ to z ! zone ( fl[4 ,illu/ration3 ,,fig4 #ai4--,two int]sect+ p>allel s]ies ( fractures produc$ ^u ea* free surface ( a prismatic block ( /iff mold]s' wax :5 brok5 by compression f ! ends 7aft] ,daubre & ,tresca74 ,9 contra/1 ! ne>-surface zone is call$ ! zone ( fracture4 ,b diff]5t rocks possess diff]5t /r5g?s1 & ^! are subject to modifications f o!r conditions1 su*1 = example1 z ! proximity ( an uncool$ magma4 ,! zone ( fl[ is !re=e jo9$ to ! zone ( fracture1 n ^u a def9ite surface1 b 9 an int]m$iate zone describ$ z ! zone ( fracture & fl[4 ,exp]im5ts :i* illu/rate ! fracture & fl[ ( solid bodies4--,a prismatic block prep>$ f /iff mold]s' wax1 if cru%$ betwe5 ! jaws ( a te/+ ma*9e1 yields a sy/em ( int]sect+ fractures :i* are p]p5dicul> to ! free surfaces ( ! block & take two directions ea* incl9$ by half ( a "r angle to ! direction ( compression 7,fig4 #ai74 ,?is exp]im5t may illu/rate ! mann] 9 :i* fractures are produc$ by ! compression )9 ! zone ( fracture ( ! li?osph]e1 z its core cont9ues to contract4 ,to reproduce ! conditions )9 ! zone ( fl[1 x w be necess>y to load ! lat]al surfaces ( ! block in/ead ( leav+ !m uncon/ra9$ z 9 ! above-describ$ exp]im5t4 ,! exp]im5t is be/ devis$ z 9 ,fig4 #bj4 ,"h a s]ies ( lay]s hav+ v>y+ degrees ( rigidity is prep>$ f beeswax z a base1 ei!r /iff5$ by admixture ( v>y+ proportions ( pla/] ( ,p>is1 or weak5$ by ! use ( ,v5ice turp5t9e4 ,su* a s]ies ( lay]s may repres5t rocks ( z widely diff]5t *>act]s z lime/one & %ale4 ,! load :i* is to repres5t sup]9cumb5t rock is suppli$ 9 ! exp]im5t by a deep lay] ( %ot4 ,illu/ration3 ,,fig4 #bj4--;,app>atus to illu/rate ! fold+ ( /rata )9 ! zone ( fl[ 7aft] ,willis74 ,:5 compression is appli$ to ! lay]s f ! ends1 ^! normally solid mat]ials1 in/ead ( fractur+1 are b5t into a s]ies ( folds4 ,! /iff]1 or m compet5t1 lay]s are f\nd to be less contort$ ?an are ! weak] lay]s1 p>ticul>ly if ! latt] h be5 protect$ "u an ar* ( ! m compet5t lay] 7pl4 #b ,a74 ,! ar*es & tr\ghs ( ! fold$ /rata4--,e s]ies ( folds is made up ( alt]nat+ ar*es & tr\ghs4 ,! ar*es ( ! /rata ! geologi/ calls anticl9es or anticl9al folds1 & ! tr\ghs he calls syncl9es or syncl9al folds 7,fig4 #ba74 ,:5 a /ratum is m]ely dropp$ 9 a b5d to a l[] level )\t produc+ a complete ar* or a complete tr\gh1 ?is half fold is t]m$ a monocl9e4 ,illu/ration3 ,,fig4 #ba4--;,diagrams repres5t+ a1 an anticl9e2 b1 a syncl9e2 & c1 a monocl9e4 ,any flexur+ ( ! /rata implies a r$uction ( _! surface area1 or1 consid]+ a s+le section1 a %ort5+4 ,if ! ar*es & tr\ghs are l[ & broad1 ! de=mation ( ! /rata is slight1 ! %ort5+ is comp>atively small1 & ! folds are describ$ z op5 7,fig4 #bb b74 ,if !y be relatively bo? high & n>r[1 ! de=mation is consid]able1 a l>g] am\nt ( cru/al %ort5+ has gone on1 & ! folds are describ$ z close 7,fig4 #bb c74 ,?is clos+ up ( ! folds may cont9ue until _! sides h practically ! same slope1 9 :i* case !y are said to be isocl9al 7,fig4 #bb d74 ,illu/ration3 ,,fig4 #bb4--;,a comp>ison ( folds to express increas+ degrees ( cru/al %ort5+ or progressive de=mation )9 ! zone ( fl[3 a1 /ratum be=e fold+2 b1 op5 folds2 c1 close folds2 d1 isocl9al folds4 ,! elem5ts ( folds4--,folds mu/ always be ?\ght ( z hav+ ext5sion 9 ea* ( ! ?ree dim5sions ( space 7,fig4 #bc71 & n z prop]ly includ$ )9 a s+le plane l ! cross sections :i* we s (t5 use 9 illu/ration4 ,a fold may be conceiv$ ( z divid$ into equal p>ts by a plane :i* passes along ! middle ( ei!r ! ar* or ! tr\gh1 & is call$ ! axial plane4 ,! l9e 9 :i* ?is plane int]sects ! ar* or ! tr\gh is ! axis1 :i* may be call$ ! cre/l9e 9 an anticl9e1 & ! tr\ghl9e 9 a syncl9e4 ,9 ! case ( _m op5 folds ! axis is practically horizontal1 b 9 m complexly fold$ regions ?is is seldom true4 ,! dep>ture ( ! axis f ! horizontal is call$ ! pit*1 & folds ( ?is type are describ$ z pit*+ folds or plung+ folds4 ,! axis is 9 reality 9 ^! cases ?r[n into a s]ies ( undulations or 8longitud9al folds01 & h5ce pit* w v>y along ! axis4 ,illu/ration3 ,,fig4 #bc4--;,anticl9al & syncl9al folds 9 /rata 7aft] ,willis74 ,illu/ration3 ,,fig4 #bd4--;,diagrams to illu/rate ! diff]5t %apes ( rock folds4 ,! %apes ( rock folds4--,by ! axial plane ea* fold is divid$ into two p>ts :i* are call$ its limbs1 :i* may h ei!r ! same or diff]5t av]age incl9ations4 ,to describe n[ ! %apes ( rock folds & n ! degree ( compression ( ! di/rict1 "s additional t]ms are necess>y4 ,anticl9es or syncl9es ^: limbs h ab\t ! same incl9ations are kn[n z upright or symmetrical folds4 ,! axial plane ( ! symmetrical fold is v]tical 7,fig4 #bd74 ,if ?is plane is incl9$ to ! v]tical1 ! folds are unsymmetrical4 ,s soon z ! /eep] ( ! two limbs has pass$ ! v]tical position & incl9es 9 ! same direction z ! flatt] limb1 ! fold is said to be ov]turn$4 ,! dep>ture f symmetry may g s f> t ! axial plane ( ! fold lies at a v flat angle1 & ! fold is !n said to be recumb5t4 ,! obs]vant travel] by tra9 along any ( ! r\tes :i* ent] ! ,alps may f 8 c> w9d[ f9d illu/rations ( mo/ ( ^! types ( rock folds1 z he may also1 ?\gh g5]ally less easily1 9 pass+ ?r\gh ! ,appala*ian ,m\nta9s4 ,illu/ration3 ,,fig4 #be4--,second>y & t]ti>y flexures sup]impos$ ^u ! prim>y ones4 ,9 regions :i* h be5 closely fold$ ! l>g] flexures ( ! /rata may be f\nd ) folds ( a small] ord] ( magnitude sup]impos$ ^u !m1 & ^! 9 turn may %[ crumpl+s ( /ill l[] ord]s4 ,x has be5 f\nd t ! folds ( ! small] ord]s ( magnitude possess ! %apes ( ! l>g] flexures1 & mu* is !re=e to be le>n$ f _! c>eful /udy 7,fig4 #be74 ,x is also q g5]ally discov]$ t p>allel planes ( ready p>t+1 :i* are describ$ z rock cleavage1 take _! c\rse p>allel to ! axial plane )9 ea* m9or fold4 ,z 0 long ago %[n by ! pione] ,briti% geologi/s1 ^! planes ( cleavage are ess5tially p>allel & foll[ ! fold axes ?r\gh\t l>ge areas4 ,,plate #b4 ,illu/ration3 ,a4 ,lay]s compress$ 9 exp]im5ts & %[+ ! effect ( a compet5t lay] 9 ! process ( fold+ 7aft] ,willis74 ,illu/ration3 ,b4 ,exp]im5tal production ( a s]ies ( p>allel ?ru/s )9 closely fold$ /rata 7aft] ,willis74 ,illu/ration3 ,c4 ,app>atus to illu/rate %e>+ action )9 ! ov]turn$ limb ( a fold4 ,! ov]?ru/ fold4--,:5ev] a /ratum is b5t1 !re is a t5d5cy = its p>ticles to be sep>at$ ^u ! convex side ( ! b5d1 at ! same "t t ^? ^u ! concave side are cr[d$ clos] toge!r--!re is t5sion 9 ! =m] case & compression 9 ! latt] 7,fig4 #bf74 ,)9 an unsymmetrical or an ov]turn$ fold1 ! peculi> di/ortions 9 ! diff]5t sections ( ! /ratum are less simple & are be/ illu/rat$ by pl4 #b ,c4 ,?is app>atus %[s two simil> piles ( pap] %eets1 ^u ! edges ( ea* ( :i* a s]ies ( circles has be5 drawn4 ,:5 n[ "o ( ! piles is b5t into an unsymmetrical fold1 x is se5 t ?r\gh an accommodation by ! pap] %eets slid+ ea* ov] its neighbor l>ge di/ortions ( ! circles h occurr$4 ,9 t /eep] limb :i* ) clos] fold+ w be ov]turn$ ! circles h be5 drawn out into long & n>r[ ellipses1 & ?is indicates t ^? rock p>ticles :i* be=e ! b5d+ 7 includ$ 9 ! circle h be5 mov$ pa/ ea* o!r 9 ! mann] ( ! blades ( a pair ( %e>s4 ,su* extreme 8%e>+0 action is ?us localiz$ 9 ! und]turn$ limb ( ! fold1 & a "t mu/ come ) cont9uation ( ! compression :5 ! fold w rupture at ?is critical place along a plane p>allel to ! longe/ axis ( ! ellipses or ne>ly p>allel to ! axial plane ( ! anticl9e4 ,su* /ructures probably occur 9 ! zone ( comb9$ fracture & fl[1 up into :i* ! b$s are =c$ 9 cases ( close compression4 ,relief ?us be+ f\nd ^u ?is plane ( fracture1 ! upp] portion ( ! fold w n[ ride ov] ! l[]1 & ! displacem5t is describ$ z a ?ru/ or ov]?ru/4 ,illu/ration3 ,,fig4 #bf4--;,a b5t /ratum to illu/rate t5sion ^u ! convex & compression ^u ! concave side 7aft] ,van ,hise74 ,9 ! long s]ies ( exp]im5ts conduct$ by ,mr4 ,bailey ,willis ( ! ,unit$ ,/ates ,geological ,survey1 all ! /ages betwe5 ! ov]turn$ fold & ! ov]?ru/ fold 7 reproduc$4 ,:]e a s]ies ( folds 0 closely compress$1 a p>allel s]ies ( ?ru/s develop$ 7pl4 #b ,b71 s t a s]ies ( slices cutt+ across neighbor+ /rata 0 slid 9 succession1 ea* ov] ! o!r1 l ! scales ^u a fi% or ! %+les ^u a ro(4 ,q rem>kable /ructures ( ?is k9d h be5 discov]$ 9 rocks ( su* closely fold$ di/ricts z ! ,nor?we/ ,highl&s ( ,scotl&1 :]e ! ov]rid+ is measur$ 9 miles4 ,ne> ! ?ru/ planes ! rocks %[ a cru%+ ( ! gra9s1 & ! planes !mselves are sometimes corrugat$ & poli%$ by ! movem5t4 ,re/oration ( mutilat$ folds4--,s9ce flexur+ ( ! rocks takes place )9 ! zone ( fl[ at a di/ance ( sev]al miles bel[ ! e>?'s surface1 x is q obvi\s t ! results ( ! process c be /udi$ only aft] "s ?\s&s ( feet ( sup]9cumb5t /rata h be5 remov$4 ,we are a little lat] to see by :at processes ?is l[]+ ( ! surface is accompli%$1 b = ! pres5t x may be suffici5t to accept ! fact1 realiz+ t be=e fold+s 9 ! /rata c rea* ! surface1 !y mu/ h pass$ ?r\gh ! upp] zone ( fracture4 ,x might p]haps be suppos$ t ! anticl9es w\ld appe> z ! m\nta9s ^u ! surface1 & occasionally ?is is true2 z1 = example1 9 ! fold$ ,jura ,m\nta9s ( we/]n ,europe4 ,m g5]ally1 ! m\nta9s h a syncl9al /ructure & ! valleys an anticl9al "o2 b z no g5]al rule c be appli$1 x is necess>y to make a re/oration ( ! truncat$ folds 9 ea* di/rict be=e _! "* c be kn[n4 ,! geological map & section4--,! e>?'s surface is 9 mo/ regions 9 l>ge "p cov]$ ) soil or ) o!r incoh]5t rock mat]ial1 s t ov] consid]able areas ! h>d rocks are hidd5 f view4 ,ea* locality at :i* ! rock is f\nd at ! e>?'s surface 89 place0 is describ$ z an outcropp+ or exposure4 ,9 a /udy ( ! region ea* su* exposure mu/ be exam9$ to det]m9e ! nature ( ! rock1 especially = ! purpose ( correlation ) neighbor+ exposures1 &1 9 addition1 bo? ! probable direction 9 :i* x is cont9u$ along ! surface--! /rike--& ! incl9ation ( its b$s--! dip4 ,if ! outcropp+s are suffici5tly num]\s1 & rock type1 /rike & dip1 may all be det]m9$1 ! folds ( ! di/rict may be re/or$ ) almo/ z mu* accuracy z ?\gh _! curves 7 ev]y:]e expos$ to view4 ,a cross section ?r\gh ! surface :i* repres5ts ! obs]v$ outcrops ) _! incl9ations & ! assum$ int]m$iate /rata 9 _! probable attitudes is describ$ z a geological section 7,fig4 #bg74 ,a map ^u :i* ! data h be5 ent]$ 9 _! correct locations1 ei!r ) or )\t assumptions conc]n+ ! cov]$ areas1 is kn[n z a geological map4 ,illu/ration3 ,,fig4 #bg4--;,a geological section bas$ ^u obs]vations at outcrops1 b ) ! truncat$ ar*es re/or$4 ,if ! axes ( folds are absolutely horizontal1 & ! surface ( ! e>? be repres5t$ z a pla91 ! l9es ( int]section ( ! truncat$ /rata ) ! gr\nd1 or ) any horizontal surface1 w give ! directions ( cont9uation ( ! individual /rata4 ,?is /rike direction is usually det]m9$ at ea* exposure by use ( a compass provid$ ) a _s level4 ,:5 t edge ( ! level$ compass :i* is p>allel to ! nor?-s\? l9e ^u ! dial is held aga9/ ! slop+ rock /ratum1 ! angle ( /rike is measur$ 9 degrees by ! compass ne$le4 ,if ! c>d9al directions h be5 plac$ 9 _! correct positions ^u ! compass dial1 ! ne$le w po9t to ! nor?we/ :5 ! /rike is nor!a/1 & vice v]sa 7,fig4 #bh a74 ,^u ! geologi/'s compass x is !re=e cu/om>y to rev]se ! initials :i* repres5t ! ea/ & we/ directions1 9 ord] t ! correct /rike may be read directly f ! dial 7,fig4 #bh b74 ,illu/ration3 ,,fig4 #bh4--;,diagram to illu/rate ! mann] ( det]m9+ ! /rike ( rock b$s at an outcropp+4 a1 a compass :i* has ! c>d9al directions 9 _! natural positions2 b1 a compass ) ! ea/ & we/ initials rev]s$ ^u ! dial2 c1 home-made cl9omet] 9 position to det]m9e ! dip4 ,by ! dip is meant ! incl9ation ( ! /ratum at any exposure1 & ?is mu/ obvi\sly be measur$ 9 a v]tical plane along ! /eepe/ l9e 9 ! b$d+ plane4 ,! dip angle is always ref]r$ to a horizontal plane1 & h5ce v]tical b$s h a dip ( #ij4 ,! device = measur+ ?is angle ( dip1 ! cl9omet]1 is m]ely a simple p5dulum :i* s]ves z an indicator & is c5t]$ at ! corn] ( a graduat$ quadrant4 ,a home-made v>iety is easily con/ruct$ f a squ>e piece ( bo>d & an atta*$ pap] quadrant 7,fig4 #bh c71 b ! geologi/'s compass is always provid$ ) a cl9omet] atta*m5t to ! dial4 ,illu/ration3 ,,fig4 #bi4--;,diagram to %[ ! use ( ,t symbols to indicate ! dip & /rike ( outcropp+s4 ,s9ce ! /rike is ! int]section ( ! b$d+ plane ) a horizontal surface1 & ! dip is ! int]section ) t p>ticul> v]tical plane :i* gives ! /eepe/ incl9ation1 ! /rike & dip are p]p5dicul> to ea* o!r4 ,to repres5t !m ^u maps1 x is m or less cu/om>y to use ! s-call$ ,t symbols1 ! top ( ! ,t giv+ ! direction ( ! /rike & ! %ank t ( ! dip4 ,if m]idians are drawn ^u ! map1 ! direction or attitude ( ! ,t c be f\nd by ! use ( a simple protractor2 & :5 ent]$ ^u ! map1 ! exact angle ( ! /rike may be suppli$ by a figure ne> ! top ( ! ,t1 & ! dip angle by a figure at ! end ( ! %ank4 ,x is ! cu/om1 also1 to make ! l5g? ( ! %ank inv]sely proportional to ! /eepness ( ! dip1 s t 9 a broad way ! attitudes ( ! /rata may be tak5 9 at a glance 7,fig4 #bi74 ,x is fur!r ( advantage to make ! top ( ! ,t a d\ble l9e1 s t "s symbol or color may %[ ! correlations ( ! diff]5t exposures4 ,to illu/rate1 9 ,fig4 #bi1 ! symbol m>k$ a repres5ts an outcrop ( lime/one1 ! /rike ( :i* is #ej ea/ ( nor? 7,n4 #ej ,e471 & ! dip ( :i* is #de s\!a/4 ,9 ! same figure b repres5ts a %ale outcrop 9 horizontal b$s1 :i* h 9 consequ5ce a univ]sal /rike & a dip ( #j4 ,an exposure ( lime/one 9 v]tical b$s :i* /rike ,n4 #fj ,e4 is %[n at c1 etc4 ,illu/ration3 ,,fig4 #cj4--;,diagram to %[ h[ ! ?ickness ( a =mation may be obta9$ f ! angle ( ! dip & ! wid? ( ! exposures4 ,measurem5t ( ! ?ickness ( =mations4--,:5 =mations /ill lie 9 horizontal b$s1 we may sometimes le>n _! ?ickness directly ei!r f ! dep? ( bor+s to ! und]ly+ rock1 or by measurem5ts ^u /eep caon walls4 ,if ! b$s /& v]tically1 ! matt] is exce$+ly simple1 = 9 ?is case ! ?ickness is ! wid? ( ! outcrops ( ! =mation betwe5 ! b$s :i* b\nd x ^u ei!r side4 ,9 ! g5]al case1 9 :i* ! b$s are nei!r horizontal nor v]tical1 ! ?ickness mu/ be obta9$ indirectly f ! wid? ( ! exposures & ! angle ( ! dip4 ,! factor by :i* ! exposure wid? mu/ be multipli$ is kn[n z ! s9e ( ! dip angle 7,fig4 #cj71 :i* is giv5 ) suffici5t accuracy = mo/ purposes 9 ! foll[+ table4 ,x is obvi\s t 9 ord] to obta9 ! full ?ickness ( a =mation x is necess>y to measure f ! contact ) ! adjac5t =mation ^u ! "o side to a simil> contact ) ! ne>e/ =mation ^u ! o!r4 ,natural ,s9es #j 4#jj #ce 4#eg #gj 4#id #e 4#ji #dj 4#fd #ge 4#ig #aj 4#ag #de 4#ga #hj 4#ih #ae 4#bf #ej 4#gg #he #a4jj #bj 4#cd #ee 4#hb #ij #a4jj #be 4#db #fj 4#hg #cj 4#ej #fe 4#ia ,illu/ration3 ,,fig4 #ca4--;,comb9$ surface & sectional views ( a plung+ anticl9e 7aft] ,willis74 ,illu/ration3 ,,fig4 #cb4--;,comb9$ surface & sectional views ( a plung+ syncl9e 7aft] ,willis74 ,! detection ( plung+ folds4--,:5 ! axis ( a fold is horizontal1 its outcrops ^u a pla9 w cont9ue to h ! same /rike until ! =mation comes to an end4 ,^u a g5]ally level surface1 !re=e1 any regul> progressive v>iation 9 ! /rike direction is an indication t ! folds h a plung+ or pit*+ "*4 ,_m s]i\s mi/akes ( int]pretation h be5 made because ( a failure to recognize ?is evid5ce ( plung+ folds4 ,! way 9 :i* ! /rikes are progressively modifi$ w be made cle> by ! diagrams ( ,figs4 #ca & #cb1 ! fir/ repres5t+ a pit*+ anticl9e & ! second a pit*+ syncl9e4 ,9 bo? ^! reciprocal cases ! /rikes ( ! b$s und]go ! same *anges1 & ! dip directions s]ve to di/+ui% :i* ( ! two /ructures is pres5t 9 a giv5 case4 ,!re is1 h[ev]1 "o fur!r diff]5ce 9 t ! h>d lay]s ( ! plung+ anticl9e1 :]e !y disappe> bel[ ! surface 9 ! axis1 w pres5t a dom$ surface slop+ =w>d l ! back ( a :ale z x rises above ! surface ( ! sea4 ,plung+ folds 9 s]ies w ?us appe> 9 ! topography z a s]ies ( %>ply zigzagg+ ranges at ^? localities :]e ! h>d] lay]s int]sect ! surface4 ,su* features are enc\nt]$ 9 ea/]n ,p5nsylvania1 :]e ! h>d =mations ( ! ,appala*ian ,m\nta9 sy/em plunge nor!a/w>d "u ! lat] =mations4 ,! pit* ( ! l>g] fold is (t5 disclos$ by t ( ! m9or puck]+s sup]impos$ ^u x4 ,illu/ration3 ,,fig4 #cc4--,uncon=mity betwe5 a l[] & an upp] s]ies ( b$s ^u ! coa/ ( ,cali=nia4 ,note h[ ! h>d lay] /&s 9 relief ^u ! connect+ surface 7aft] ,fairbanks74 ,! mean+ ( an uncon=mity4--,! rock b$s1 :i* are deposit$ "o above ! o!r dur+ a transgression ( ! sea1 are usually p>allel & ?us repres5t a cont9u\s process ( deposition4 ,su* b$s are said to be con=mable4 ,:]e1 ^u ! o!r h&1 two s]ies ( deposits :i* are n p>allel to ea* o!r are sep>at$ by a break1 !y are said to =m uncon=mable s]ies1 & ! break or surface ( junction is an uncon=mity 7,fig4 #cc74 ,"h x is evid5t t ! s$im5ts :i* compose ! l[] s]ies ( b$s h be5 fold$ 9 ! zone ( fl[1 ?\gh ! upp] s]ies has evid5tly escap$ ?is vicissitude4 ,fur!rmore1 ! surface :i* delimits ! l[] s]ies f ! upp] is some:at irregul> & %[s a h>d lay] /&+ 9 relief1 z x w\ld if x _h oppos$ great] resi/ance to ! attacks ( ! atmosph]e ^u x4 ,illu/ration3 ,,fig4 #cd4--,s]ies ( diagrams to illu/rate 9 succession ! episodes involv$ 9 ! hi/orical developm5t ( an angul> uncon=mity4 ,! v]tical arr[s indicate direction ( movem5t ( ! l&1 & ! horizontal arr[s ! direction ( %ore migration4 ,9 reality1 an uncon=mity betwe5 =mations mu/ be int]pret$ to mean t ! l[] s]ies is n only old] ?an ! upp]1 z %[n by ! ord] ( sup]position1 b t ! "t ( its deposition 0 sep>at$ f t ( ! upp] by a hiatus 9 :i* important *anges took place 9 ! l[] s]ies4 ,! /ages or episodes 9 ! hi/ory ( ! b$s repres5t$ 9 ,fig4 #cc may be read z foll[s 7see ,fig4 #cd a-e73-- 7a7 ,deposition ( ! l[] s]ies dur+ a transgression ( ! sea4 7b7 ,cont9u$ subsid5ce & burial ( ! l[] s]ies b5ea? ov]ly+ s$im5ts1 & flexur+ 9 ! zone ( fl[4 7c7 ,elevation ( ! comb9$ deposits to & f> above sea level & removal by erosion ( va/ ?icknesses ( ! upp] s$im5ts4 7d7 ,a new subsid5ce ( ! truncat$ l[] s]ies & deposition ( ! upp] s]ies across its erod$ surface4 7e7 ,a new elevation ( ! d\ble s]ies to its pres5t position above sea level4 ,illu/ration3 ,,fig4 #ce4--,types ( deceptive or erosional uncon=mities4 ,f ?is succession ( episodes x is se5 t a break ( ?is k9d betwe5 two s]ies ( deposits involves a d\ble oscillation ( subsid5ce foll[$ by elevation--a l>ge depression foll[$ by a l>ge elevation1 a small] subsid5ce foll[$ by elevation4 ,! "t int]val :i* mu/ h be5 repres5t$ by ^! repeat$ op]ations is s va/ z at fir/ to /agg] ! m9d 9 contemplat+ x4 ,:51 z 9 ?is in/ance1 ! dips ( ! l[] s]ies ( b$s diff] f ^? ( ! upp]1 we h to d ) an angul> uncon=mity4 ,x may be1 h[ev]1 t ! l[] s]ies 0 n s f> depress$ z to ent] ! zone ( fl[1 & t its b$s meet ^? ( ! upp] s]ies ) app>5t con=mity4 ,su* an uncon=mity is (t5 extremely difficult to recognize1 & x is describ$ z a deceptive or erosional uncon=mity4 ,) a deceptive uncon=mity ! clew to its real nature is usually "s fact :i* indicates t ! l[] s]ies ( s$im5ts _h be5 rais$ above ! level ( ! sea be=e ! upp] s]ies 0 deposit$ ^u x4 ,?is may be app>5t ei!r 9 ! irregul>ity ( ! surface on :i* ! two s]ies are jo9$1 9 "s evid5ce ( ! action ( waves su* z w\ld be furni%$ by a basal conglom]ate 9 ! upp] s]ies1 or "s indication ( diff]5t resi/ance ( diff]5t rocks ( ! l[] s]ies to attacks ( ! atmosph]e ^u !m 7,figs4 #cc & #ce a-c74 ,9 mo/ cases1 at lea/1 ! l[e/ memb] ( ! upp] s]ies w be a diff]5t type ( rock f ! upp]mo/ memb] ( ! l[] s]ies1 h5ce ! frequ5t occurr5ce ( ! discordant cross b$d+ 9 s&/one %\ld n deceive ev5 ! novice into ! assumption ( an uncon=mity4 ,,read+ ,,ref]5ces ,,to ,,*apt] ,v ,! zones ( fracture & fl[3-- ,c4 ,r4 ,,van ,,hise4 ,pr9ciples ( ,nor? ,am]ican ,precambrian ,geology1 #af? ,ann4 ,rept4 ,u4,s4 ,geol4 ,surv41 #ahie1 ,pt4 ,i1 pp4 #eha-fjc4 ,,bailey ,,willis4 ,me*anics ( ,appala*ian ,/ructure1 #ac? ,ann4 ,rept4 ,u4,s4 ,geol4 ,surv41 #ahic1 ,pt4 ,,ii1 pp4 #bag-bec4 ,a4 ,,daubr,e4 tudes ,syn?tiques de ,gologie ,exprim5tale4 ,p>is1 #ahgi1 pp4 #cjf-cbh1 pl4 ,,ii4 ,w4 ,,pr9z4 ,quelques rem>ques gnrales propos de l'essai de c>te tectonique de la belgique1 etc41 ,bull4 ,soc4 ,belge ,geol41 vol4 #ah1 #aijd1 p4 #adc1 pl4 ,v4 ,analysis ( folds3-- ,,van ,,hise & ,,willis z above2 ,,de ,,m>g]ie et ,,heim2 ,les dislocations de l'corce t]re/re 79 ,fr5* & ,g]man languages74 ,zuri*1 #ahhh4 ,geological maps3-- ,,wm4 ,h4 ,,hobbs4 ,! ,mapp+ ( ! ,cry/all9e ,s*i/s1 ,j\r4 ,geol41 vol4 #aj1 #aijb1 pp4 #ghj-gib1 #heh-hij4 ,,*apt] ,,vi ,,! ,,ar*itecture ,,( ,,! ,,fractur$ ,,sup]/ructure ,illu/ration3 ,,fig4 #cf4--;,a set ( ma/] jo9ts develop$ 9 %ale ^u ! %ores ( ,cayuga ,lake ne> ,i?aca1 ,new ,york 7aft] ,u4 ,s4 ,g4 ,s474 ,illu/ration3 ,,fig4 #cg4--;,diagram to %[ h[ sets ( ma/] jo9ts diff]+ 9 direction by half a "r angle may abruptly replace ea* o!r4 ,illu/ration3 ,,fig4 #ch4--;,diagram to %[ ! diff]5t comb9ations ( ! s]ies compos+ two d\ble sets ( ma/] jo9ts1 & 9 a1 a1 a additional disord]ly fractures4 ,! sy/em ( ! fractures4--,9 ref]r+ to exp]im5ts made ^u ! fracture ( solid blocks "u compression 7p4 #da71 x 0 %[n t two s]ies ( p>allel fractures develop p]p5dicul> to ea* free surface ( ! block1 & t ^! s]ies are ea* ( !m incl9$ by half ( a "r angle to ! direction ( compression1 & ?us p]p5dicul> to ea* o!r4 ,! fragm5ts into :i* a block ) "o free surface w\ld ?us t5d to be divid$ %\ld be squ>e prisms p]p5dicul> to ! free surface4 ,x w\ld be int]e/+1 if x 7 practicable1 to le>n f exp]im5t h[ ^! prisms w\ld be fur!r fractur$ by a cont9uation ( ! compression4 ,f me*anical consid]ations involv+ ! resolution ( =ces ) ref]5ce to ! ready-=m$ fractures1 x seems probable t ! next s]ies ( fractures to =m w\ld bisect ! angles ( ! fir/ d\ble s]ies or set4 ,:]ev] rocks are f\nd expos$ 9 _! orig9al attitudes1 !y are1 9 fact1 se5 to be int]sect$ by two p>allel s]ies ( fractures :i* are p]p5dicul> to ! e>?'s surface & to ea* o!r & are describ$ z jo9ts4 ,9 _m cases m ?an two s]ies ( su* fractures are f\nd1 yet ev5 9 ^! cases two m p]fectly develop$ s]ies are prom95t & almo/ exactly p]p5dicul> to ea* o!r z well z to ! e>?'s surface4 ,?is omnipres5t d\ble s]ies or set ( jo9ts is ! well-kn[n set ( ma/] jo9ts1 & v (t5 x is f\nd develop$ practically alone 7,fig4 #cf74 ,ov] l>ge areas1 ! direction ( ! set ( ma/] jo9ts may rema9 practically con/ant1 or ?is set may q sudd5ly give place to a simil> set :i* is1 h[ev]1 turn$ ?r\gh half a "r angle f ! fir/ 7,fig4 #cg74 ,n infrequ5tly two su* sets ( ma/] jo9ts are f\nd toge!r bisect+ ea* o!r's angles )9 ! same rocks1 & to !m are sometimes add$ additional ?\gh less p]fect s]ies ( jo9t planes4 ,/udi$ ?r\gh\t a consid]able di/rict1 ! v>i\s s]ies :i* make up ^! two sets ( ma/] jo9ts may be se5 locally develop$ 9 diff]5t comb9ations z well z 9 association ) additional fissure planes :i* are n easily r$uc$ to any simple law ( arrangem5t 7,fig4 #ch a1 a1 a74 ,only r>ely are regul> jo9t s]ies obs]v$ :i* d n /& p]p5dicul> to ! orig9al attitude ( ! rock b$s4 ,9 a few localities1 h[ev]1 rectangul> jo9t sets h be5 discov]$ :i* divide ! rock into prisms p>allel to ! e>?'s surface & ) ! jo9t s]ies incl9$ to x ea* by half a "r angle4 ,:]e ! rock b$s h be5 mu* di/urb$1 ! complex ( jo9ts may be su* z to defy all attempts at ord]ly arrangem5t4 ,illu/ration3 ,,fig4 #ci4--,view on ! %ore at ,hol/5sborg1 ,we/ ,gre5l&1 to %[ ! subequal spac+ ( ! jo9ts 7aft] ,korn]up74 ,illu/ration3 ,,fig4 #dj4--,view ( an expos$ hillside 9 ,icel& ^u :i* ! sn[ collect$ 9 crannies along ! jo9ts br+s out to advantage bo? ! l>g] & ! small] int]vals ( ! jo9t sy/em 7aft] ,?orodds574 ,! space int]vals ( jo9ts4--,! same k9d ( subequal spac+ :i* *>act]izes ! fractures ne> ! surface ( ! block 9 ,daubre's exp]im5t 7,fig4 #ai1 p4 #da7 is f\nd simulat$ by ! rock jo9ts 7,fig4 #ci74 ,su* unit int]vals betwe5 fractures may be gr\p$ toge!r into l>g] units :i* are sep>at$ by fractures ( unusual p]fection4 ,we may ?9k ( su* l>g] space units z hav+ ! small] ones sup]impos$ ^u !m 7,fig4 #dj74 ,! displacem5ts ^u jo9ts--faults4--,9 ! va/ majority ( cases1 ! jo9t fractures :5 c>efully exam9$ betray no evid5ce ( any appreciable movem5t ( ! two walls ^u ea* o!r4 ,g5]ally ! rock lay]s are se5 to cross ! jo9ts )\t app>5t displacem5t4 ,jo9ts are !re=e planes ( disjunction only1 & n planes ( displacem5t4 ,illu/ration3 ,,fig4 #da4--;,fault$ blocks ( basalt divid$ by jo9ts ne> ,woodbury1 ,connecticut4 ,to %[ ! /ructure ( ! rock1 "s ( ! foliage has be5 remov$ 9 prep>+ ! sket* f a photograph4 ,)9 _m di/ricts1 h[ev]1 a displacem5t may be se5 to h occurr$ ^u c]ta9 ( ! jo9t planes1 & ^! are !n describ$ z faults4 ,su* displacem5ts ( necessity imply a diff]5tial movem5t ( sections or blocks ( ! e>?'s cru/1 ! s-call$ orographic blocks1 :i* are b\nd$ by ! jo9t planes & play individual rles 9 ! movem5t4 ,a simple case ( su* displacem5ts 9 rocks int]sect$ by a s+le set ( ma/] jo9ts is repres5t$ 9 ! model ( plate #d ,c4 ,! mo/ prom95t fault repres5t$ by ?is model runs l5g?wise ?r\gh ! middle1 & ! displacem5t :i* is measur$ ^u x n only v>ies betwe5 wide limits1 b is m>k$ by abrupt *anges at ! m>g9s ( ! l>g] blocks4 ,?is v]tical displacem5t ^u ! fault is call$ its ?r[4 ,?\gh n illu/rat$ by ! model1 horizontal displacem5ts may likewise occur1 & ^! w be m fully discuss$ :5 ! subject ( e>?quakes is consid]$ 9 ! foll[+ *apt]4 ,an actual example ( blocks displac$ by v]tical adju/m5t is repres5t$ 9 ,fig4 #da1 a simple type ( fault+ :i* has tak5 place 9 rocks b slightly di/urb$ f _! orig9al attitude1 b int]sect$ by a relatively simple sy/em ( ma/] jo9ts4 ,9 ^? regions :]e ! b$s h be5 fold$ & p]haps ov]?ru/ be=e _! elevation into ! zone ( fracture1 & :i* are fur!r int]sect$ by disord]ly fissure planes1 ! results are f> m complex4 ,9 su* cases ! planes ( individual displacem5t may n be v]tical1 ?\gh !y are g5]ally /eep] ?an #de4 ,= _! description x is necess>y to make use ( additional te*nical t]ms 7,fig4 #db74 ,! incl9ation ( a slop+ fault plane measur$ aga9/ ! v]tical is call$ ! hade ( ! fault4 ,! total displacem5t is measur$ along ! plane ( ! fault f a po9t ^u "o limb to ! po9t f :i* x 0 sep>at$ 9 ! o!r4 ,! additional t]ms are made suffici5tly cle> by ! diagram4 ,illu/ration3 ,,fig4 #db4--;,a fault 9 previ\sly di/urb$ /rata4 ,,ab1 displacem5t2 ,,ac1 ?r[2 ,,bd1 /ratigraphic ?r[2 ,,bc1 heave2 angle ,,cab1 hade4 ,me?ods ( detect+ faults4--,! fir/ effect ( a fault is usually to produce a crack at ! surface ( ! e>?2 &1 provid$ !re is a v]tical displacem5t or ?r[1 an esc>pm5t :i* rises ^u ! up?r[n side ( ! fault4 ,9 g5]al x may be said t esc>pm5ts :i* appe> at ! e>?'s surface z plane surfaces probably repres5t planes ( fracture1 ?\gh n necess>ily planes ( fault+4 ,9 _m cases ! actual displacem5ts lie buri$ "u loose rock dbris ne> to & p>allel+ ! esc>pm5t1 & 9 "s cases z a result ( ! erosional processes work+ ^u alt]nately h>d & s(t lay]s ( rock1 ! esc>pm5t may lat] appe> ^u ! d[n?r[n side or limb ( ! fault 7,fig4 #dc74 ,z an illu/ration ( a fault esc>pm5t1 ! faade ( ,el ,capitan & _m o!r rock faces ( ! ,yosemite valley may be in/anc$4 ,illu/ration3 ,,fig4 #dc4--;,diagrams to %[ h[ an esc>pm5t orig9ally on ! up?r[n side ( ! fault may1 ?r\gh erosion1 appe> ^u ! d[n?r[n side4 ,illu/ration3 ,,fig4 #dd4--;,a fault plane exhibit+ 8drag40 ,! op5+ is artificial 7aft] ,scott74 ,:5 we h fur!r /udi$ ! erosional processes at ! e>?'s surface1 x w be appreciat$ t faults t5d to quickly bury !mselves f sight1 :]eas fold /ructures w long rema9 9 evid5ce4 ,_m faults w ?us be ov]look$1 & too great weight is likely to be ascrib$ to ! folds 9 acc\nt+ = ! exi/+ attitudes & positions ( ! rock masses4 ,faults mu/ !re=e be s\ght out if mi/akes ( int]pretation are to be avoid$4 ,! mo/ satisfactory evid5ce ( a fault is ! discov]y ( a rock b$ :i* may be easily id5tifi$1 & :i* is actually se5 displac$ on a plane ( fracture :i* int]sects x 7,fig4 #db1 p4 #ei74 ,:5 su* an easily recognizable lay] is n to be f\nd1 ! plane ( displacem5t may p]haps be discov]$ z a n>r[ zone compos$ ( angul> fragm5ts ( ! rock cem5t$ toge!r by m9]als :i* =m out ( solution 9 wat]4 ,su* a fractur$ rock zone :i* foll[s a plane ( fault+ is a fault breccia4 ,if ! fault breccia1 or ve9 rock1 is mu* /rong] ?an ! rock on ei!r side1 x may ev5tually /& 9 relief at ! surface l a dike or wall4 ,at o!r times ! displacem5t produces little fracture ( ! walls1 b !y slide ov] ea* o!r 9 su* a mann] z to yield ei!r a smoo?ly corrugat$ or an ev5ly poli%$ surface :i* is describ$ z 8slick5sides40 ,x may be1 h[ev]1 t dur+ ! movem5t ei!r "o or bo? ( ! walls h 8dragg$01 & s are curl$ back 9 ! imm$iate neighborhood ( ! fault plane 7,fig4 #dd74 ,:51 z is q g5]ally ! case1 ! actual plane ( displacem5t ( a fault is n op5 to inspection1 ! movem5t may be prov5 by ! obs]vation ( abrupt1 z contra/$ ) gradual1 *anges 9 ! /rikes & dips ( neighbor+ exposures 7,fig4 #de72 or by not+ t "s easily recogniz$ =mation has be5 %>ply (fset 9 its outcrops 7,fig4 #df74 ,illu/ration3 ,,fig4 #de4--,map to %[ h[ a fault may be indicat$ 9 abrupt *anges ( ! /rike & dip ( neighbor+ exposures4 ,illu/ration3 ,,fig4 #df4--;,a s]ies ( p>allel faults indicat$ by successive (fsets 9 ! c\rse ( an easily recognizable rock =mation4 ,!re are 9 addition _m indications r ?an pro(s ( ! pres5ce ( faults1 :i* mu/ be tak5 acc\nt ( 9 e g5]al /udy ( ! geology ( a di/rict4 ,?us ! outcrops ( all neighbor+ =mations may t]m9ate abruptly ^u a /raight l9e :i* int]sects all alike4 ,deep-seat$ fissure spr+s may be align$ 9 a /rik+ mann]1 & s indicate ! c\rse ( a prom95t fracture1 ?\gh n necess>ily ( a fault4 ,mu* ! same may be said ( ! dikes ( cool$ magma :i* h be5 inject$ along prexi/+ fractures4 ,! base ( ! geological map4--,mod]n topographic maps =m an important "p ( ! libr>y ( ! s]i\s /ud5t ( physiography2 !y are ! gazette] ( ?is bran* ( sci5ce4 ,e civiliz$ nation has to-day ei!r complet$ a topographic atlas ( its t]ritory1 or x is vigor\sly prosecut+ a survey to furni% maps :i* repres5t ! relief ) "s detail1 & publi%+ ! results 9 ! =m ( an atlas ( quadrangles4 ,?us a relief map w erelong be obta9able ( any "p ( ! civiliz$ _w1 & may be pur*as$ 9 sep>ate sections4 ,n[h]e is ?is "w be+ tak5 up ) great] vigor ?an 9 ! ,unit$ ,/ates1 :]e a va/ doma9 repres5t+ e type ( topographic peculi>ity is be+ attack$ f _m c5t]s4 ,"h & else:]e ! relief ( ! l& is be+ express$ by s-call$ cont\rs or l9es ( equal altitude ^u ! e>?'s surface4 ,x is z ?\gh a s]ies ( horizontal planes1 sep>at$ by uni=m int]vals ( #bj or #dj or #ajj feet1 _h be5 made to int]sect ! surface1 & ! int]section curves1 aft] consecutive num]ation1 _h be5 dropp$ into a s+le plane = pr9t+4 ,:]e ! slopes are /eep1 ! cont\r l9es 9 ! topographic map w appe> cr[d$ toge!r & s produce a deep %ade ^u ! map2 :]eas ) relatively flat surfaces :ite pat*es w /& out prom95tly ^u ! map4 ,m & m ! topographic map is com+ into use1 & = ! /ud5t ( nature 9 p>ticul> x is important to acquire facility 9 int]pret+ ! relief f ! topographic map4 ,to fur!r ?is end1 a special model has be5 devis$1 & its use is describ$ 9 app5dix ,c4 ,usually be=e any satisfactory geological map c be prep>$1 a cont\r$ topographic map ( ! di/rict to be /udi$ mu/ be available4 ,! field map & ! areal geological map4--,z ! atlas ( topographic maps is ! physiographic gazette]1 s geological maps toge!r con/itute ! ref]5ce diction>y ( descriptive geology4 ,n only are topographic maps ( _m di/ricts n[ g5]ally available1 b m & m x has become ! policy ( gov]nm5ts to supply geological maps 9 ! same quadrangle =m :i* is ! unit ( ! topographic map4 ,! geological map is1 h[ev]1 a complex ( s _m conv5tional symbols1 t )\t "s practical exp]i5ce 9 ! actual prep>ation ( "o1 x is exce$+ly difficult = ! /ud5t to compreh5d its significance4 ,a mod]n geological map is usually a rectangul> %eet pr9t$ 9 color1 ^u :i* are _m irregul> areas ( individual hue jo9$ to ea* o!r l ! p>ts ( a *ild's picture puzzle4 ,! color$ areas ^u ! geological map are ea* suppos$ to indicate :]e a c]ta9 rock type or =mation lies imm$iately bel[ ! surface1 & ?is di/ribution repres5ts ! be/ judgm5t ( ! geologi/ :o1 aft] a /udy ( ! di/rict1 has prep>$ ! map4 ,un=tunately ! conv5tions 9 use are su* t 8 obs]vation & 8 !ory h be5 hopelessly int]m+l$ 9 ! f9i%$ product4 ,arm$ ) ! geological map1 ! /ud5t :o visits ! di/rict f9ds spread out be=e him1 x may be1 a l&scape ( hill & valley1 ( gre5 =e/ & br[n f>m+ l&1 :i* is z diff]5t z may be f ! color$ puzzle :i* he holds 9 8 h&4 ,hidd5 "u ! f>m vegetation or mask$ by ! woods are scatt]$ outcropp+s ( rock :i* h be5 ! basis ( ! geologi/'s judgm5t 9 prep>+ ! map4 ,exp]i5ce %[s t 9 ord] to bridge ! wide gap betwe5 ! geology 9 ! l&scape & ! pat*es ( color ^u ! map some?+ m ?an m]e exam9ation ( ! color$ %eet is necess>y4 ,we %all !re=e describe1 ) ! aid ( laboratory models1 ! v>i\s /ages necess>y to ! prep>ation ( a geological map1 & e /ud5t %\ld be advis$ to foll[ ?is by practical /udy ( "s small area :]e rocks are f\nd 9 outcrop4 ,?\gh ! publi%$ areal geological map repres5ts bo? fact & !ory1 ! map mak] reta9s an unpubli%$ field map or map ( obs]vations1 ^u :i* ! f9al map has be5 bas$4 ,?is field map %[s ! location ( ea* outcrop t has be5 /udi$1 ) a record ( ! k9d ( rock & ( su* obs]vations z /rike1 dip1 & pit*4 ,our task w !re=e be to prep>e3 7#a7 a field map2 7#b7 an areal geological map2 & 7#c7 "s typical geological sections4 ,laboratory models = ! /udy ( geological maps4--,9 ord] to repres5t 9 ! laboratory ! disposition ( rock outcrops 9 ! field1 special laboratory tables are prep>$ ) removable cov]s & ) fix$ tops1 :i* are divid$ into squ>es numb]$ l ! t[n%ip sections ( ! national doma9 7,fig4 #dg74 ,to repres5t ! rock outcrops1 blocks are prep>$ :i* may be fix$ 9 any desir$ position by fitt+ a p9 into a small augur hole bor$ ?r\gh ! table4 ,! outcrop blocks = ! s$im5t>y rock types are s con/ruct$ z to %[ ! /rike & dip ( ! b$s4 7,see ,app5dix ,d47 ,illu/ration3 ,,fig4 #dg4--;,field map prep>$ f a laboratory table4 ,! me?od ( prep>+ ! map4--,to prep>e ! map1 use is made ( a geological compass ) cl9omet] atta*m5t1 a protractor1 & a map base divid$ into sections l ! top ( ! table1 & on ! scale ( "o in* to ! foot4 ,ea* exposure repres5t$ ^u ! table is 8visit$0 & !n locat$ ^u ! base map 9 its prop] position & attitude4 ,! result is ! field map 7,fig4 #dg71 :i* ?us repres5ts ! facts only1 unless !re h be5 unc]ta9ties 9 ! correlation ( exposures or 9 det]m9+ ! position ( ! b$d+ plane4 ,illu/ration3 ,,fig4 #dh4--;,areal geological map con/ruct$ f ! field map ( ,fig4 #dg1 ) two select$ geological sections4 ,to prep>e ! areal geological map f ! field map1 x is fir/ necess>y to fix ! b\nd>ies :i* sep>ate =mations at ! surface2 & n[ p]haps = ! fir/ "t x is realiz$ h[ l>ge an elem5t ( unc]ta9ty may ent] if ! exposures 7 widely sep>at$4 ,x is cle> t no two p]sons w draw ^! l9es 9 ! same positions ?r\gh\t1 ?\gh c]ta9 portions ( !m--:]e ! facts are m ne>ly adequate--may correspond4 ,9 ,fig4 #dh is repres5t$ ! areal geological map con/ruct$ f ! field map1 ) ! d\btful area at "o side left blank4 ,"s conclusions f ?is map may n[ be pr(itably consid]$4 ,! complexly fold$ s&/one =mation at ! left ( ! map appe>s z ! olde/ memb] repres5t$1 s9ce its area has be5 cut ?r\gh by ! intrusive granite :i* does n intrude o!r =mations1 & is uncon=mably ov]laid by ! lime/one & its basal lay] ( conglom]ate4 ,! lime/one 9 turn is uncon=mably ov]laid by ! m]ely tilt$ s&/one b$s at ! "r ( ! map4 ,^! ?ree s$im5t>y =mations cle>ly repres5t decreas+ am\nts ( close fold+1 f :i* x is cle> t ea* e>li] =mation has pass$ ?r\gh an episode n %>$ by t ( next y\ng] age4 ,( ! o!r intrusive rocks1 ! dike ( porphyry is y\ng] ?an all ! o!r =mations1 ) ! possible exception ( ! upp] s&/one4 ,(fsett+ ( ! =mations has disclos$ ! c\rse ( a fault1 & f its relations to ! dikes we may le>n t ( ^! ! porphyry is y\ng] & ! basalt old] ?an ! date ( ! fault+4 ,! da%$ l9es ^u ! map 7,,ab & ,,cd7 h be5 select$ z appropriate l9es along :i* to con/ruct geological sections 7,fig4 #dh1 bel[ map71 & f ^! sections ! expos$ ?icknesses ( ! diff]5t =mations may be calculat$4 ,9 "o in/ance only1 t ( ! conglom]ate1 c we be sure t ?is expos$ ?ickness measures ! entire =mation4 ,fold v]sus fault topography4--,! m resi/ant or 8/rong]0 rock b$s1 z reg>ds attacks ( ! atmosph]e1 9 ! c\rse ( "t come to /& 9 relief1 sep>at$ by depressions :i* ov]lie ! 8weak]0 =mations4 ,simple op5 folds :i* are n plung+ ex]cise an influ5ce ^u topography by produc+ g5]ally long & /raight ridges4 ,m complex flexures1 s9ce !y g5]ally plunge1 make !mselves app>5t by features :i* 9 ! map are repres5t$ by curves4 ,fracture /ructures1 & especially block displacem5ts1 are diff]5tiat$ f ^! curv+ features by ! dom9ance ( /raight or ne>ly rectil9e> l9es ^u ! map4 ,! effect ( erosion is to r$uce ! asp]ity ( features & to mold !m ) fl[+ curves4 ,! fracture /ructures are = ?is reason mu* m likely to be ov]look$1 & if !y are n to elude ! obs]v]1 !y mu/ be s\ght out ) c>e4 ,fold & fracture /ructures may bo? be reveal$ ^u ! same map4 ,,read+ ,,ref]5ces ,,to ,,*apt] ,,vi ,jo9t sy/ems3-- ,,john ,,phillips4 ,obs]vations made 9 ! ,neighborhood ( ,f]rybridge 9 ! ,ye>s #ahbf-ahbh1 ,phil4 ,mag41 #b;d s]41 vol4 #d1 #ahbh1 pp4 #dja-dji2 ,illu/rations ( ! geology ( ,york%ire1 ,pt4 ,,ii1 ,! ,lime/one ,di/rict4 ,london1 #ahcf1 pp4 #ij-ih4 ,,samuel ,,haughton4 ,on ! ,physical ,/ructure ( ! ,old ,r$ ,s&/one ( ! ,c\nty ( ,wat]=d1 consid]$ ) ref]5ce to cleavage1 jo9t surfaces1 & faults1 ,trans4 ,roy4 ,soc4 ,london1 vol4 #adh1 #aheh1 pp4 #ccc-cdh4 ,w4 ,c4 ,,br,,gg]4 ,spalt5v]w]fung5 9 d] ,geg5d ,langesund-,ski51 ,nyt ,magaz9 = ,naturvid]nskab]ne1 vol4 #bh1 #ahhd1 pp4 #bec-dai4 ,,wm4 ,h4 ,,hobbs4 ,! ,new>k ,sy/em ( ! ,pomp]aug ,valley1 ,connecticut1 #ba/ ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ,,iii1 #aija1 pp4 #he-adc4 ,geological map3-- ,,wm4 ,h4 ,,hobbs4 ,! ,int]pretation ( ,geological ,maps1 ,s*ool ,sci5ce & ,ma!matics1 vol4 #i1 #aiji1 pp4 #fdd-fec4 ,,*apt] ,,vii ,,! ,,int]rupt$ ,,"* ,,( ,,e>? ,,movem5ts3 ,,e>?quakes ,,& ,,seaquakes ,nature ( e>?quake %ocks4--,man's belief 9 ! /ability ( ,"m ,e>?--! t]ra firma--is s inbr$ 9 8 nature t ev5 a light %ock ( e>?quake br+s a rude awak5+4 ,! t]ror :i* x inspires is no d\bt l>gely to be expla9$ by ?is disillusionm5t f ! mo/ fundam5tal ( 8 beliefs4 ,7 he bett] advis$1 ! long p]iods ( quiet :i* sep>ate e>?quakes1 & n ! light] %ocks :i* foll[ all gr&] di/urbances1 w\ld occasion him conc]n4 ,illu/ration3 ,,fig4 #di4--,view ( a portion ( ! ru9s ( ,mess9a aft] ! e>?quake ( ,decemb] #bh1 #aijh4 ,e>?quakes are ! s5sible manife/ations ( *anges 9 level or ( lat]al adju/m5ts ( portions ( ! cont95ts1 & ! seismic di/urbances ^u ! sea--seaquakes & seismic sea waves--relate to simil> *anges ^u ! floor ( ! ocean4 ,dur+ ! gr&] or cata/rophic e>?quakes1 ! *anges are inde$ t]rify+1 & h usually be5 accompani$ by losses to life & prop]ty1 :i* are only to be comp>$ ) ^? ( great conflagrations or ( inundations on ?ickly populat$ pla9s4 ,! conflagration has all too frequ5tly be5 an aft]ma? ( ! great hi/oric e>?quakes4 ,! e>?quake ( ,decemb] #bh1 #aijh1 9 s\!rn ,italy1 de/roy$ almo/ ! entire population ( a great city1 & left ( its massive build+s only a confus$ heap ( rubble 7,fig4 #di74 ,two ye>s lat] a heavy e>?quake result$ 9 great damage to cities 9 ,co/a ,rica 7,fig4 #ej71 :ile two ye>s e>li] our own c\ntry 0 fir/ really awak5$ to ! dang] 9 :i* x /&s f ^! convulsive e>? ?roes2 ?\gh1 z we %all see1 ^! dang]s c be l>gely met ?r\gh prop] me?ods ( con/ruction4 ,illu/ration3 ,,fig4 #ej4--,ru9s ( ! ,c>negie ,palace ( ,peace at ,c>tago1 ,co/a ,rica1 de/roy$ :5 almo/ complet$ by ! great e>?quake ( ,may #d1 #aiaj 7aft] a photograph by ,re>-,admiral ,s+]1 ,u4,s4,n474 ,e>?quakes are usually prec$$ = a brief in/ant by subt]ranean rumbl+s ^: int5sity appe>s to be> no relation to ! %ocks :i* foll[4 ,! gr\nd !n rocks 9 wavelike motions1 :i*1 if ( l>ge amplitude1 may induce nausea1 prev5t animals f keep+ ^u _! feet1 & wreck all /ructures n specially adapt$ to )/& !m4 ,heavy bodies are sometimes ?r[n up f ! gr\nd 7,fig4 #ea71 & at o!r times simil> heavy masses are1 app>5tly because ( _! in]tia1 m deeply imb$d$ 9 ! e>?4 ,?us grave/ones & heavy /one po/s are (t5 sunk m deeply 9 ! gr\nd & are surr\nd$ by a holl[ & p]haps by small op5 cracks 9 ! surface 7,fig4 #eb74 ,:5 bodies are ?r[n upw>d1 x w\ld imply t a quick upw>d movem5t ( ! gr\nd _h be5 sudd5ly arre/$1 :ile ! burial ( heavy bodies 9 ! e>? is probably due to a movem5t :i* beg9s sudd5ly & is less abruptly t]m9at$4 ,illu/ration3 ,,fig4 #ea4--;,b[ld]s ?r[n into ! air & ov]turn$ dur+ ! ,assam e>?quake ( #ahig 7aft] ,r4 ,d4 ,oldham74 ,illu/ration3 ,,fig4 #eb4--;,heavy po/ sunk deep] into ! gr\nd dur+ ! ,*>le/on e>?quake ( ,augu/ #ca1 #ahhf 7aft] ,dutton74 ,seaquakes & seismic sea waves4--,^u ! ocean ! quakes :i* emanate f ! sea floor are felt on %ipbo>d z sudd5 jolt+s :i* produce ! impression t ! %ip has /ruck ^u a %oal1 ?\gh 9 mo/ in/ances !re is no visible commotion 9 ! wat]4 ,! di/ribution ( ^! %ocks1 z indicat$ ei!r by ! exp]i5ces ( neighbor+ %ips at ! "t ( a p>ticul> %ock1 or by ! records ( vessels :i* at diff]5t times h sail$ ov] an area ( frequ5t seismic di/urbance1 appe>s to be limit$ to n>r[ zones or l9es 7,fig4 #ec74 ,! same t5d5cy ( "u-sea di/urbances to be localiz$ ^u def9ite /raight l9es has be5 (t5 illu/rat$ by ! behavior ( deep-sea cables :i* are laid 9 proximity to "o ano!r & :i* h be5 kn[n to "p simultane\sly at po9ts rang$ ^u a /raight l9e4 ,illu/ration3 ,,fig4 #ec4--,map %[+ ! localities at :i* %ocks h be5 report$ at sea (f ,cape ,m5doc9o1 ,cali=nia4 ,f> gr&] di/urbances ^u ! floor ( ! ocean h be5 reveal$ by ! great sea waves--! s-call$ 8tidal waves01 prop]ly ref]r$ to z tsunamis--:i* recur 9 ^? sea di/ricts :i* adjo9 ! special e>?quake zones ^u ! cont95ts 7p4 #hf74 ,! =]unn] ( su* a sea wave approa*+ ! %ore is usually a sudd5 )drawal ( ! wat] s z to lay b>e a portion ( ! bottom1 b ?is is well-recogniz$ to be ! premonition ( a gigantic oncom+ wave :i* sweeps all be=e x & is only halt$ :5 x has roll$ ov] all ! l[-ly+ c\ntry & enc\nt]$ a m\nta9 wall4 ,su* seismic waves h be5 especially common ^u ! ,pacific %ore ( ,s\? ,am]ica & ^u ! ,japanese littoral 7,fig4 #ed74 ,^! waves proce$ f above ! great deeps ^u ! ocean bottom1 & cle>ly result f ! gr&] e>? movem5ts to :i* ^! depressions owe _! exceptional dep?4 ,! )drawal ( ! wat] f neighbor+ %ores may be presum$ to be connect$ ) a desc5t ( ! floor ( ! depression & ! consequ5t draw+-9 ( ! ocean surface above4 ,! lat] high wave w\ld ?us repres5t ! disp]sion ( ! m\nta9 ( wat] :i* is rais$ by ! meet+ ( ! wat]s f ! diff]5t sides ( ! depression4 ,illu/ration3 ,,fig4 #ed4--;,effect ( a seismic wat] wave at ,kamai%i1 ,japan1 9 #ahif 7aft] ,e4 ,r4 ,scidmore74 ,illu/ration3 ,,fig4 #ee4--;,a fault ( v]tical displacem5t4 ,! gr&] & ! less] e>? movem5ts4--,^u ! l& ! gr&] & s-call$ cata/rophic e>?quakes are usually ! accompanim5t ( important *anges 9 ! surface ( ! gr\nd t w be discuss$ 9 lat] sections4 ,^? %ocks :i* d little damage to /ructures produce no visible *anges 9 ! e>?'s surface1 except1 x may be1 to %ake d[n "s wat]-soak$ masses ( e>? ^u ! /eep] slopes4 ,/ill o!r movem5ts1 & ^! too slight to be felt ev5 9 ! night :5 ! animal _w is at re/1 may yet be di/+ui%$ by _! s\nds1 ! unmi/akable rumbl+s :i* are *>act]i/ic alike ( ! heavie/ & ! lighte/ ( e>?quake %ocks4 ,illu/ration3 ,,fig4 #ef4--;,esc>pm5t produc$ by an e>?quake fault ( v]tical displacem5t :i* cut across ! ,*$rang ,riv] & ?us produc$ a wat]fall1 ,assam e>?quake ( #ahig 7aft] ,r4 ,d4 ,oldham74 ,*anges 9 ! e>?'s surface dur+ e>?quakes--faults & fissures4--,ea* ( ! gr&] among hi/oric e>?quakes has be5 accompani$ by notewor?y *anges 9 ! configuration ( ! e>?'s surface )9 ! di/rict :]e ! %ocks 7 mo/ int5se4 ,a section ( ! gr\nd is usually f\nd to h mov$ ) ref]5ce to ano!r ^u ! o!r side ( a v]tical plane :i* is usually to be se52 we h "h to d ) ! actual mak+ ( a fault or displacem5t su* z we f9d ! fossil examples ( )9 ! rocks4 ,! displacem5t1 or ?r[1 ^u ! fault plane may be ei!r upw>d or d[nw>d or lat]ally 9 "o direction or ! o!r1 or ^! movem5ts may be comb9$4 ,a movem5t ( adjac5t sections ( ! gr\nd upw>d or d[nw>d ) ref]5ce to ea* o!r 7,fig4 #ee7 has be5 (t5 obs]v$1 notably at ,midori aft] ! great ,japanese e>?quake ( #ahia1 & 9 ! ,*$rang valley ( ,assam aft] ! e>?quake ( #ahig 7,fig4 #ef74 ,illu/ration3 ,,fig4 #eg4--;,a fault ( lat]al displacem5t4 ,illu/ration3 ,,fig4 #eh4--;,f5ce p>t$ & displac$ fifte5 feet by a transv]se fault =m$ dur+ ! ,cali=nia e>?quake ( #aijf 7aft] ,w4 ,b4 ,scott74 ,illu/ration3 ,,fig4 #ei4--;,fault ) v]tical & lat]al displacem5ts comb9$4 ,a lat]al ?r[1 unaccompani$ by appreciable v]tical displacem5t 7,fig4 #eg71 is especially well illu/rat$ by ! fault 9 ,cali=nia :i* 0 =m$ dur+ ! e>?quake ( #aijf 7,fig4 #eh74 ,a comb9ation ( ! two types ( displacem5t 9 "o 7,fig4 #ei7 is exemplifi$ by ! ,bai%iko fault ( ,=mosa at ! place %[n 9 plate #c ,a4 ,! measure ( displacem5t4--,to af=d "s measure ( ! displacem5ts :i* h be5 obs]v$ ^u e>?quake faults1 x may be /at$ t ! maximum v]tical ?r[ measur$ ^u ! fault 9 ! ,neo valley ( ,japan 7#ahia7 0 #ah feet1 9 ! ,*$rang valley ( ,assam 7#ahig7 #ce feet1 & ( ! ,alaskan coa/ 7#ahii7 #dg feet4 ,l>ge sections ( l& 7 bodily uplift$ 9 ^! cases )9 ! space ( a few seconds1 or at mo/ a few m9utes1 by ! am\nts giv54 ,! l>ge/ record$ lat]al displacem5t measur$ ^u an e>?quake fault is ab\t #ba feet ^u ! ,cali=nia rift aft] ! e>?quake ( #aijf2 ?\gh an am\nt only slightly less ?an ?is is indicat$ 9 ! %ift+ ( roads & arroyas dat+ f ! e>?quake ( #ahgb 9 ! ,ow5s valley1 ,cali=nia4 ,fault l9es once e/abli%$ are planes ( special weakness & become lat] ! seat ( repeat$ movem5ts ( ! same k9d4 ,,plate #c4 ,illu/ration3 ,a4 ,an e>?quake fault op5$ 9 ,=mosa 9 #aijf1 ) v]tical & lat]al displacem5ts comb9$ 7aft] ,omori74 ,illu/ration3 ,b4 ,e>?quake faults op5$ 9 ,alaska 9 #ahhi1 on :i* v]tical slices ( ! e>?'s %ell h und]gone individual adju/m5ts 7aft] ,t>r & ,m>t974 ,illu/ration3 ,,fig4 #fj4--;,diagram to %[ h[ small faults 9 ! rock basem5t may be mask$ at ! surface ?r\gh adju/m5ts )9 ! loose rock mantle4 ,! great] numb] ( e>?quake faults are f\nd 9 ! loose rock cov] :i* s g5]ally mantles ! firm] rock basem5t1 & x is almo/ c]ta9 t ! ?r[s )9 ! solid rock are consid]ably l>g] ?an ^? :i* are "h measur$ at ! surface1 ow+ to ! adju/m5ts :i* s readily take place 9 ! loos] mat]ials4 ,^? light] %ocks ( e>?quake :i* are accompani$ by no visible displacem5ts at ! surface d1 h[ev]1 9 "s in/ances affect 9 a measure ! fl[ ( wat] ^u ! surface1 & ?us indicate t small *anges ( surface level h occurr$ )\t breaks suffici5tly %>p to be p]ceiv$ 7,fig4 #fj74 ,int]m$iate betwe5 ! /eep esc>pm5t & ! mask$ displacem5t j describ$ is ! s-call$ 8mole-hill0 effect1--a r\nd$ & v>i\sly crack$ slope or ridge above ! position ( a buri$ fault 7,fig4 #fa74 ,illu/ration3 ,,fig4 #fa4--;,diagram to %[ ! appe>ance ( a 8mole hill0 above a buri$ e>?quake fault 7aft] ,kot74 ,! esc>pm5ts due to e>?quake faults 9 loose mat]ials at ! e>?'s surface c obvi\sly reta9 _! /eepness = a few ye>s or decades at ! mo/2 = because ( _! v]ticality !y mu/ gradually disappe> 9 r\nd$ slopes "u ! action ( ! elem5ts4 ,small] displacem5ts )9 a rock :i* rapidly dis9tegrates "u ! action ( fro/ & sun w likewise be=e long be effac$4 ,9 ^? exceptional in/ances :]e a resi/ant rock type has _h all alt]$ upp] lay]s plan$ away until a fre% & h>d surface is expos$1 & has fur!r be5 protect$ f ! fro/ & sun b5ea? a ?9 lay] ( soil1 its orig9al surface may be reta9$ unalt]$ = _m c5turies4 ,^u su* a surface ! lighte/ ( s5sible %ocks1 or ev5 ! small] e>? movem5ts :i* are n p]ceiv$ at ! "t1 may leave an almo/ indelible record4 ,su* records p>ticul>ly %[ t ! movem5ts :i* !y regi/] occur ^u ! planes ( jo9t+ )9 ! rock1 & t ^! ready =m$ cracks h probably be5 ! seats ( repeat$ & cumulative adju/m5ts 7,fig4 #fb74 ,illu/ration3 ,,fig4 #fb4--,po/-glacial e>?quake faults ( small b cumulative displacem5t1 ea/]n ,new ,york 7aft] ,woodwor?74 ,illu/ration3 ,,fig4 #fc4--;,e>?quake cracks 9 ,colorado des]t 7aft] a photograph by ,sau]v574 ,contraction ( ! e>?'s surface dur+ e>?quakes4--,! wide v>iations 9 ! am\nt ( ! lat]al displacem5t ^u e>?quake faults1 l ^? op5$ 9 ,cali=nia 9 #aijf1 %[ t at ! "t ( a heavy e>?quake !re mu/ be l>ge local *anges 9 ! d5sity ( ! surface mat]ials4 ,lit]ally1 ?\s&s ( fissures may appe> 9 ! l[l&s1 _m ( !m no d\bt a second>y effect ( ! %ak+1 b o!rs1 l ! quebradas ( ! s\!rn ,&es or ! 8e>?quake cracks0 9 ! ,colorado des]t 7,fig4 #fc71 may h a deep]-seat$ orig94 ,_m facts g to %[1 h[ev]1 t ?\gh local expansion does occur 9 "s localities1 a surface contraction is a f> m g5]al consequ5ce ( e>? movem5t4 ,9 civiliz$ c\ntries ( high indu/rial developm5t1 :]e l9es ( metal ( "o k9d or ano!r run = long di/ances b5ea? or ^u ! surface ( ! gr\nd1 su* g5]al contraction ( ! surface may be easily prov54 ,comp>atively seldom are l9es ( metal pull$ ap>t 9 su* a way z to %[ an expansion ( ! surface2 :]eas buckl+s & k9k+s ( ! l9es appe> 9 _m places to prove t ! area )9 :i* !y are f\nd has1 z a :ole1 be5 r$uc$4 ,illu/ration3 ,,fig4 #fd4--;,diagrams to %[ h[ railway tracks are ei!r brok5 or buckl$ locally )9 ! di/rict visit$ by an e>?quake4 ,illu/ration3 ,,fig4 #fe4--,! ,biwajima railroad bridge 9 ,japan aft] ! e>?quake ( #ahia 7aft] ,milne & ,burton74 ,illu/ration3 ,,fig4 #ff4--;,diagrams to %[ h[ ! compression ( a di/rict & its consequ5t contraction dur+ an e>?quake may close up ! jo9t spaces )9 ! rock basem5t & conc5trate ! contraction ( ! ov]ly+ mantle :]e ?is is p>tially cut ?r\gh & s weak5$ 9 ! valley sections4 ,wat] pipes laid 9 ! gr\nd at a dep? ( "s feet may be b[$ up into an ar* :i* appe>s above ! surface2 l9es ( curb+ are rais$ into brok5 ar*es1 & ! tracks ( railways are ?r[n into local loops & k9ks :i* imply a v consid]able local contraction ( ! surface 7,fig4 #fd74 ,) unv>y+ regul>ity railway or o!r bridges :i* cross riv]s or rav9es1 if ! /ructures are s]i\sly damag$1 indicate t ! riv] banks h drawn ne>] toge!r at ! "t ( ! di/urbance4 ,9 su* cases1 :5ev] ! bridge gird] has rema9$ 9 place ^u its abutm5ts1 ^! h ei!r be5 brok5 or back-tilt$ z a :ole 9 su* a mann] z to indicate an approa* ( ! f\ndations :i* 0 prev5t$ at ! top by ! /iffness ( ! gird] 7,fig4 #fe74 ,illu/ration3 ,,fig4 #fg4--,map ( ! ,*$rang fault :i* made its appe>ance dur+ ! ,assam e>?quake ( #ahig4 ,! figures give ! am\nts ( ! local v]tical displacem5t measur$ 9 feet 7aft] ,r4 ,d4 ,oldham74 ,! simple/ explanation ( su* an approa* ( ! banks at ! sides ( ! valleys cut 9 loose surface mat]ial is to be f\nd 9 a g5]al clos+ up ( ! jo9t spaces )9 ! und]ly+ rock1 & an adju/m5t ( ! mantle ^u ! floor ma9ly 9 ! valley sections 7,fig4 #ff74 ,illu/ration3 ,,fig4 #fh4--,map giv+ ! displacem5ts 9 feet measur$ along an e>?quake fault =m$ 9 ,alaska 9 #ahii 7aft] ,t>r & ,m>t974 ,! plan ( an e>?quake fault4--,9 our consid]ation ( e>?quake faults we h ?us f> giv5 our att5tion to ! displacem5t z view$ at a s+le locality only4 ,su* displacem5ts are1 h[ev]1 cont9u$ = _m miles1 & sometimes = hundr$s ( miles2 & :5 n[ we exam9e a map or plan ( su* a l9e ( fault+1 new facts ( l>ge significance make _! appe>ance4 ,?is may be well illu/rat$ by a /udy ( ! plan ( ! ,*$rang fault :i* appe>$ at ! "t ( ! ,assam e>?quake ( #ahig 7,fig4 #fg74 ,f ?is map x w be notic$ t ! upw>d or d[nw>d displacem5t ^u ! p]p5dicul> plane ( ! fault is n uni=m1 b is subject to l>ge & sudd5 *anges4 ,?us 9 ord] ! measurem5ts 9 feet are #cb1 #j1 #ah1 #ce1 #j1 #h1 #be1 #ab1 #h1 #b1 #j4 ,! fault =m$ 9 #ahii ^u ! %ores ( ,russell ,fjord 9 ,alaska 7,fig4 #fh7 reveals simil> sudd5 *anges ( ?r[1 only t "h ! direction ( ! movem5t is (t5 rev]s$2 or1 o!rwise express$1 ! up?r[ is sudd5ly transf]r$ f "o side ( ! fault to ! o!r4 ,su* abrupt *anges 9 ! direction ( ! displacem5t h be5 obs]v$ ^u _m e>?quake faults1 & a p>ticul>ly /rik+ "o is repres5t$ 9 ,fig4 #fi4 ,illu/ration3 ,,fig4 #fi4--;,abrupt *ange 9 ! direction ( ?r[ ^u an e>?quake fault :i* 0 =m$ 9 ! ,ow5s valley1 ,cali=nia1 9 #ahgb4 ,! obs]v] looks directly along ! c\rse ( ! fault f ! left =egr\nd to ! cliff beyond & to ! left ( ! imp\nd$ wat] 7aft] a photograph by ,w4 ,d4 ,johnson74 ,! block movem5ts ( ! di/urb$ di/rict4--,! displacem5ts ^u e>?quake faults are ?us se5 to be subdivid$ into sections1 ea* ( :i* diff]s f its neighbors ^u ei!r side & is %>ply sep>at$ f !m1 at lea/ 9 _m in/ances4 ,^! po9ts ( abrupt *ange ( displacem5t are1 9 _m cases at lea/1 ! int]section po9ts ) transv]se faults 7,fig4 #fi74 ,su* po9ts ( abrupt *ange 9 ! degree or 9 ! direction ( ! displacem5t may be1 :5 look$ at f above1 abrupt turn+ po9ts 9 ! direction ( ext5sion ( ! fault1 ^: c\rse ^u ! map appe>s z a zigzag l9e made up ( /raight sections connect$ by %>p elb[s 7,fig4 #gj74 ,illu/ration3 ,,fig4 #gj4--,map ( ! faults )9 an area ( ! ,ow5s valley1 ,cali=nia1 =m$ 9 "p dur+ ! e>?quake ( #ahgb1 & 9 "p due to e>ly di/urbances1 ,9 ! we/]n portions ! displacem5ts cut across firm rock & alluvial deposits alike )\t deviation ( direction 7aft] a map by ,w4 ,d4 ,johnson74 ,su* a gr\p+ ( surface faults z are repres5t$ ^u ! map is evid5ce t ! area ( ! e>?'s %ell1 :i* is includ$1 has at ! "t ( ! e>?quake be5 subject to adju/m5ts z a s]ies ( sep>ate units or blocks1 c]ta9 ( ! b\nd>ies ( :i* are ! fault l9es repres5t$4 ,! *anges 9 displacem5t measur$ ^u ! l>g] faults make x cle> t ! obs]v$ faults c repres5t b a fraction ( ! total numb] ( l9es ( displacem5t1 ! o!rs be+ mask$ by v>iations 9 ! compactness ( ! loose mantl+ deposits4 ,c\ld we b h ?is mantle remov$1 we %\ld d\btless f9d a rock floor sep>at$ into p>ts l an anci5t ,pompeiian pavem5t1 ! individual blocks 9 :i* h be5 ?r[n1 "s upw>d & "s d[nw>d1 by v>y+ am\nts4 ,less ?an a hundr$ miles away to ! ea/w>d f ! ,ow5s ,valley1 a portion ( ?is pavem5t has be5 uncov]$ 9 ! ext5sive op]ations ( ! ,tonapah ,m9+ ,di/rict1 s t !re we may /udy 9 all its detail ! elaborate patt]n ( e>? m>quetry 7,fig4 #ga7 :i* = ! floor ( ! ,ow5s valley is z yet d5i$ u4 ,illu/ration3 ,,fig4 #ga4--,m>quetry ( ! rock floor ( ! ,tonapah ,m9+ ,di/rict1 ,nevada 7aft] ,spurr74 ,illu/ration3 ,,fig4 #gb4--,map ( a portion ( ! ,alaskan coa/ to %[ ! adju/m5ts 9 level dur+ ! e>?quake ( #ahii 7aft] ,t>r & ,m>t974 ,! e>? blocks adju/$ dur+ ! ,alaskan e>?quake ( #ahii4--;,= a /udy ( ! adju/m5ts :i* take place betwe5 neighbor+ e>? blocks dur+ a great e>?quake1 ! rec5t ,alaskan di/urbance has (f]$ ! advantage t ! mo/ affect$ di/rict 0 ^u ! seacoa/1 :]e *anges ( level c\ld be ref]r$ to ! datum ( ! sea's surface4 ,"h a great isl& & l>ge sections ( ! neighbor+ %ore und]w5t movem5ts bo? z a :ole 9 l>ge blocks & 9 adju/m5ts ( _! subord9ate p>ts among !mselves 7,fig4 #gb74 ,"s sections ( ! coa/ 7 "h elevat$ by z mu* z #dg feet1 :ile neighbor+ sections 7 uplift$ by small] am\nts 7,fig4 #gc71 & c]ta9 small] sections 7 ev5 dropp$ bel[ ! level ( ! sea4 ,illu/ration3 ,,fig4 #gc4--,view on ,ha5cke ,isl&1 ,dis5*antm5t ,bay1 ,alaska1 reveal+ ! %ore t rose sev5te5 feet above ! sea dur+ ! e>?quake ( #ahii1 & 0 f\nd ) b>nacles /ill cl++ to ! rock 7aft] ,t>r & ,m>t974 ,! am\nt ( su* subsid5ce is1 h[ev]1 difficult to asc]ta91 = ! reason t ! =m] %ore features are n[ cov]$ ) wat] & ?us remov$ f obs]vation4 ,9 favorable localities ! m9imum am\nt ( subm]g5ce may sometimes be measur$ ^u =e/ trees :i* are n[ flood$ ) sea wat]4 ,9 ,fig4 #gd a portion ( ! coa/ is repres5t$ :]e ! bea* s& is n[ ext5d$ back into ! spruce =e/1 a di/ance ( a hundr$ feet or m1 & :]e s$gy bea* grass is gr[+ among trees ^: roots are n[ lav$ 9 salt wat]4 ,at ! front ( ?is =e/ ! great /orm waves ov]turn ! trees & pile ! wreckage 9 front ( ^? t /ill rema9 /&+4 ,illu/ration3 ,,fig4 #gd4--,p>tially subm]g$ =e/ ^u ! %ore ( ,knight ,isl&1 ,alaska1 due to ! s9k+ ( a section ( ! coa/ dur+ ! e>?quake ( #ahii 7aft] ,t>r & ,m>t974 ,illu/ration3 ,,fig4 #ge4--,settlem5t ( a section ( ! %ore at ,port ,royal1 ,jamaica1 dur+ ! e>?quake ( ,janu>y #ad1 #aijg1 adjac5t to a simil> b l>g] settlem5t ( ! ne> %ore dur+ ! e>?quake ( #afib 7aft] a photograph by ,br[n74 ,^u ! glaciat$ rock surfaces ( ! ,alaskan coa/1 exceptionally favorable opportunities are f\nd = /udy ( ! intricate patt]n ( ! e>? mosaic :i* is "u adju/m5t at ! "t ( an e>?quake4 ,^u ,gannett ,nunatak ! surface 0 f\nd divid$ by p>allel faults into di/9ct slices :i* individually und]w5t small *anges ( level 7plate #c ,b74 ,,*apt] ,,viii ,,! ,,int]rupt$ ,,"* ,,( ,,e>? ,,movem5ts3 ,,e>?quakes ,,& ,,seaquakes 7,conclud$7 ,exp]im5tal demon/ration ( e>? movem5ts4--,! /udy ( ! ,alaskan e>?quake ( #ahii %[$ t dur+ ?is adju/m5t )9 ! e>?'s %ell "s ( ! local blocks mov$ upw>d & by l>g] am\nts ?an _! neighbors1 & t /ill o!rs 7 actually depress$ s t ! sea fl[$ ov] !m4 ,x mu/ be evid5t t su* diff]5tial v]tical movem5ts ( neighbor+ blocks at ! e>?'s surface c only take place if lat]al transf]s ( mat]ial are made b5ea? x4 ,f "u ^? /rips ( coa/ l& :i* 7 depress$1 mat]ial mu/ h be5 mov$ s z to fill ! void :i* w\ld o!rwise h =m$ b5ea? ! sections t 7 uplift$4 ,if we take into consid]ation mu* l>g] fractions ^u ! surface ( our planet1 we are taught by ! great seaquakes :i* are n[ regi/]$ ^u e>?quake in/rum5ts at di/ant /ations t l>ge d[nw>d movem5ts are to-day 9 progress b5ea? ! sea mu* m ?an suffici5t to comp5sate all ext5sions ( ! e>?'s surface )9 ^? di/ricts :]e ! l& is ris+ 9 m\nta9s4 ,f "u ! (f%ore deeps ( ! ocean to b5ea? ! gr[+ m\nta9s ^u ! %ore1 a transf] ( e>? mat]ial mu/ be assum$ to take place :5 di/urbances are regi/]$4 ,)9 ! "t int]val t sep>ates ! sudd5 adju/m5ts ( ! surface :i* are manife/$ 9 e>?quakes1 ! condition ( /ra9 :i* br+s !m ab\t is /eadily accumulat+1 due1 z we g5]ally assume1 to e>? contraction ?r\gh loss ( its heat4 ,x seems probable t ! resi/ance to an imm$iate adju/m5t is f\nd 9 ! rigidity ( ! %ell because ( ! compression to :i* x is subject$4 ,to illu/rate3 a r[ ( blocks well fitt$ to ea* o!r may be held firmly z a bridge betwe5 ! jaws ( a vice1 because s soon z ea* block />ts to fall a l>ge resi/ance f friction ^u its surface is call$ into exi/5ce1 a =ce :i* increases ) ! degree ( compression4 ,x is ?us possible ^u ?is assumption crudely to demon/rate ! adju/m5t ( e>? blocks by ! simple device repres5t$ 9 plate #d ,a4 ,! con/ruction ( ?is exp]im5tal tank is s simple t little explanation is necess>y4 ,wood5 blocks ( diff]5t heights are support$ 9 wat] )9 a tank hav+ a glass front1 & are kept 9 a /ra9$ condition at o!r ?an _! natural positions ( flotation by ! compression ( a simple vice at ! top4 ,held firmly 9 ?is position1 !y may ?us repres5t ! neighbor+ blocks )9 ! e>?'s out] %ell :i* are support$ ^u relatively yield+ mat]ials b5ea?1 & prev5t$ f at once adju/+ !mselves to _! natural positions ?r\gh ! compression to :i* !y are subject$4 ,held z !y n[ are1 ! wat] ne> ! ends ( ! tank is =c$ up b5ea? ! blocks to high] ?an its natural level1 & ?us t5ds to fl[ f bo? ends t[>d ! c5t]4 ,su* a movem5t w\ld p]mit ! end blocks to drop & =ce ! middle ones to rise4 ,! end blocks are1 let u say1 ! sections ( ,alaskan coa/ l9e :i* sunk dur+ ! e>?quake1 z ! c5t] blocks are ! sections :i* rose ! full measure ( #dg feet4 ,^u a l>g] scale ! end blocks may equally well be consid]$ z ! floor ( ! great deeps (f ! ,alaskan coa/1 ^: s9k+ at ! "t ( ! e>?quake 0 ! cause ( ! great sea wave4 ,^u ?is assumption ! c5t] blocks w\ld repres5t ! ,alaskan coa/ reg>d$ z a :ole1 :i* und]w5t a g5]al uplift4 ,?\gh we may n1 9 our exp]im5t1 v>y ! t5d5cy to adju/m5t by any contractional *anges 9 ei!r ! wat] or ! blocks1 we may r$uce ! compression ( ! vice1 :i* leads to ! same g5]al result4 ,z ! compression ( ! vice is sl[ly relax$1 a po9t is at la/ rea*$ at :i* friction ^u ! block surfaces is no long] suffici5t to prev5t an adju/m5t tak+ place1 & ?is n[ sudd5ly occurs ) ! result %[n 9 plate #d ,b4 ,9 ! case ( ! e>? blocks1 ?is sudd5 adju/m5t is accompani$ by mass movem5ts ( ! gr\nd sep>at$ by faults1 & ^! movem5ts produce successional vibrations t are p>ticul>ly l>ge ne> ! block m>g9s1 & o!r frictional vibrations ( su* small measure z to be g5]ally appreciat$ by s\nds only4 ,! jolt ( ! adju/m5ts has ?r[n "s blocks beyond _! natural position ( re/1 & ^! s9k & rise subsequ5tly 9 ord] to readju/ !mselves ) light] vibrations1 :i* may be repeat$ & cont9u$ = "s "t4 ,9 ! case ( ! e>? ^! lat] adju/m5ts are ! s-call$ aft]%ocks :i* usually cont9ue ?r\gh\t a consid]able p]iod foll[+ e great e>?quake4 ,gradually !y fall (f 9 int5sity & frequ5cy until !y c no long] be felt1 & are !reaft] cont9u$ = a "t z rumbl+s only4 ,,plate #d4 ,illu/ration3 ,a4 ,exp]im5tal tank to illu/rate ! e>? movem5ts :i* are manife/$ 9 e>?quakes4 ,! sections ( ! e>?'s %ell are "h repres5t$ be=e adju/m5t has tak5 place4 ,illu/ration3 ,b4 ,! same app>atus aft] a sudd5 adju/m5t4 ,illu/ration3 ,c4 ,model to illu/rate a block displacem5t 9 rocks :i* are int]sect$ by ma/] jo9ts4 ,d]angem5t ( wat] fl[ by e>? movem5t4--,! wat] :i* support$ ! blocks 9 our exp]im5t has repres5t$ ! m mobile portion ( ! e>?'s sub/ance b5ea? its out] zone ( fracture4 ,! surface wat] lay]s 9 ! tank may1 h[ev]1 be consid]$ 9 a diff]5t way1 s9ce _! behavior is rem>kably l t ( ! wat] )9 & ^u ! e>?'s surface dur+ an e>? adju/m5t4 ,at ! in/ant :5 adju/m5t takes place 9 ! tank1 wat] frequ5tly spurts upw>d f ! cracks betwe5 ! s9k+ end blocks2 & if 9 place ( "o ( ! high] c5t] blocks we ins]t "o ^: top is bel[ ! level ( ! wat] 9 ! tank1 a 8lake0 w be =m$ above x4 ,:5 ! adju/m5t occurs1 ?is lake is imm$iately dra9$ by outfl[ ( ! wat] at its bottom along "o ( ! cracks betwe5 ! blocks 7,fig4 #gf74 ,illu/ration3 ,,fig4 #gf4--;,diagrams to illu/rate ! dra9+ ( lakes dur+ e>?quakes4 ,su* d]angem5ts ( wat] fl[ z h be5 illu/rat$ by ! exp]im5t are among ! commone/ ( ! ph5om5a :i* accompany e>?quakes4 ,lakes & swamp l&s h dur+ e>?quakes be5 sudd5ly dra9$1 f\nta9s ( wat] h be5 se5 to %oot up f ! surface & h play$ = "s m9utes or h\rs be=e _! sudd5 disappe>ance 9 a suck+ d[n ( ! wat] ) lat] readju/m5t4 ,dur+ ! great e>?quake ( ! l[] ,mississippi valley 9 #ahaa1 kn[n z ! ,new ,madrid e>?quake1 ! e>li] ,lake ,eulalie 0 completely dra9$1 & ^u ! n[ expos$ b$ !re appe>$ p>allel fissures on :i* 7 rang$ funnel-l op5+s d[n :i* ! wat] _h be5 suck$4 ,9 o!r sections ( ! affect$ region ! wat] %ot up 9 %eets along fissures to ! tops ( high trees4 ,areas :]e su* spurt+ up ( ! wat] has be5 obs]v$ h 9 mo/ cases be5 %[n to correspond to areas ( depression1 & su* areas h sometimes be5 left flood$ ) wat]4 ,dur+ ! ,indian e>?quake ( #ahai an area ( "s #bjj squ>e miles sudd5ly sank & 0 trans=m$ into a lake4 ,illu/ration3 ,,fig4 #gg4--;,diagram to illu/rate-! d]angem5ts ( fl[ ( wat] at ! "t ( an e>?quake2 wat] issu+ at ! surface ov] d[n?r[n rocks1 & be+ suck$ d[n 9 up?r[n blocks4 ,illu/ration3 ,,fig4 #gh4--,mud cones align$ ^u a fissure op5$ at ,moraza1 ,s]via1 dur+ ! e>?quake ( ,april #d1 #aijd 7aft] ,mi*ailovit*74 ,s& or mud cones & crat]lets4--,f a v mod]ate dep? bel[ ! surface to t ( sev]al miles1 all pore spaces & all l>g] op5+s )9 ! rock are completely fill$ ) wat]1 ! 8trunk l9es0 ( ^: circulation is by way ( ! jo9ts or along ! b$d+ planes ( ! rocks4 ,! pr9cipal res]voirs1 s to speak1 ( ?is wat] inclos$ )9 ! rock are ! por\s s& =mations4 ,:51 n[1 dur+ an e>?quake a block ( ! e>?'s %ell is sudd5ly sunk & z sudd5ly arre/$ 9 its d[nw>d movem5t1 ! effect is to compress ! por\s lay]s & s =ce ! conta9$ wat] upw>d along ! jo9ts to ! surface1 c>ry+ ) x l>ge quantities ( ! s& 7,fig4 #gg74 ,illu/ration3 ,,fig4 #gi4--,"o ( ! _m crat]lets =m$ ne> ,*>le/on1 ,s\? ,c>ol9a1 dur+ ! e>?quake ( ,augu/ #ca1 #ahhf4 ,! op5+ is tw5ty feet across1 & ! leaves ab\t x are encas$ 9 s& z 7 ^? ^u ! bran*es ( ! ov]hang+ trees to a height ( "s tw5ty feet 7aft] ,dutton74 ,illu/ration3 ,,fig4 #hj4--;,cross section ( a crat]let to %[ ! trumpet-l =m ( ! s& column4 ,eject$ at ! surface ?is wat] appe>s 9 f\nta9s usually arrang$ 9 l9e ov] jo9ts1 or ev5 9 cont9u\s %eets1 & ! s& collect+ ab\t ! jets builds up l9es ( s& or mud cones sometimes describ$ z 8mud volcanoes0 7,fig4 #gh74 ,! am\nt ( s& ?us p\r$ out is sometimes s great t blankets ( quicks& are spread ov] l>ge sections ( ! c\ntry4 ,mo/ frequ5tly1 h[ev]1 ! s& is n built above ! g5]al level ( ! surface1 b =ms a s]ies ( crat]lets :i* are l>gely %ap$ z ! wat] is suck$ d[n at ! "t ( ! readju/m5t ) :i* ! play ( su* e>?quake f\nta9s is t]m9at$ 7,fig4 #gi74 ,subsequ5t excavations made ab\t su* crat]lets h %[n !m to h ! =m ( a trumpet1 & t 9 ! s& :i* s l>gely fills !m !re are g5]ally f\nd scales ( mica & su* light bodies z w\ld be pick$ out f ! het]og5e\s mat]ials ( ! s& lay]s & c>ri$ upw>d 9 ! ru% ( wat] to ! surface 7,fig4 #hj74 ,! e>?'s zones ( heavy e>?quake4--,s9ce e>?quakes give notice ( a *ange ( level ( ! gr\nd1 ! special dang] zones f ?is s\rce are ! gr[+ m\nta9 sy/ems :i* are usually f\nd ne> ! bord]s ( ! sea4 ,su* l9es ( m\nta9s are to-day ris+ :]e = long p]iods 9 ! pa/ 7 ! bas9s ( deposition ( =m] seas4 ,!y ?us repres5t ! zones ^u ! e>?'s surface :i* are ! mo/ un/able--:i* 9 ! rec5t p]iod h und]gone ! greate/ *anges ( level4 ,illu/ration3 ,,fig4 #ha4--,map ( ! isl& ( ,is*ia to %[ h[ ! %ocks ( rec5t e>?quakes h be5 conc5trat$ at ! cross+ po9t ( two fractures 7aft] ,m]calli & ,john/on-,lavis74 ,by f> ! mo/ un/able belt ^u ! e>?'s surface is ! rim surr\nd+ ! ,pacific ,ocean1 )9 :i* m>g9 x has be5 e/imat$ t ab\t #ed p] c5t ( ! record$ %ocks ( e>?quake h occurr$4 ,next 9 importance = seismic in/ability is ! zone :i* bord]s bo? ! ,m$it]ranean ,sea & ! ,c>ibbean--! ,am]ican ,m$it]ranean--& is ext5d$ across c5tral ,asia ?r\gh ! ,himalayas into ,malaysia4 ,bo? zones approximate to great circles ^u ! e>?'s surface & int]sect ea* o!r at an angle ( ab\t #fg4 ,x has be5 e/imat$ t ab\t #ie p] c5t ( ! record$ cont95tal e>?quakes h emanat$ f ^! belts4 ,illu/ration3 ,,fig4 #hb4--;,a l9e ( e>? fracture indicat$ 9 ! plan ( ! relief1 :i* may at any "t become ! seat ( movem5t & resultant %ock4 ,! special l9es ( heavy %ock4--,)9 any e>?quake di/rict ! %ocks are n felt ) equal sev]ity at all places1 b !re are1 on ! contr>y1 def9ite l9es :i* ! di/urbance seems to se>* out = special damage4 ,f _! relations to ! relief ( ! l& ^! l9es w\ld appe> to be l9es ( fracture ^u ! b\nd>ies ( ^? sections ( ! cru/ t play individual rles 9 ! block adju/m5t :i* takes place4 ,m or less mask$ z ^! l9es are b5ea? ! r\nd$ curves ( ! l&scape1 !y are giv5 an altoge!r un5viable prom95ce ) ea* succe$+ e>?quake4 ,at su* times we may ?9k ( ! e>?'s surface z specially s5sitiz$ = lay+ b>e its hidd5 /ructure1 z is ! s5sitiz$ plate "u ! magical influ5ce ( ! ,x rays4 ,:51 at ! "t ( an e>?quake1 blocks are adju/$ ) ref]5ce to _! neighbors1 ! movem5ts ( oscillation are greate/ 9 ^? m>g9al portions ( direct contact4 ,corn]s ( blocks--! int]sect+ po9ts ( ! important faults--%\ld = ! same reason be %ak5 ) a d\ble viol5ce1 & ?is assumption appe>s to be confirm$ by obs]vation4 ,^u ! isl& ( ,is*ia1 (f ! ,bay ( ,naples1 ! %ocks f rec5t e>?quakes h be5 /rangely conc5trat$ ne> ! t[n ( ,casamicciola1 :i* 0 la/ de/roy$ 9 #ahhc4 ,?is un=tunate city lies at ! cross+ po9t ( important fractures ^: c\rse ^u ! isl& is m>k$ by num]\s spr+s & suffioni 7,fig4 #ha74 ,seismotectonic l9es4--,! l9es ( important e>? fractures1 z w be m cle>ly %[n 9 ! sequel 7p4 #bbg71 are (t5 indicat$ ) "s cle>ness by /raight l9es 9 ! plan ( ! surface relief 7,fig4 #hb74 ,l9es ( ?is nature are easily made out ^u ! map ( ! ,we/ ,indies1 & if we repres5t ^u x by circles ( diff]5t diamet]s ! comb9$ int5sities ( ! record$ e>?quakes 9 ! v>i\s cities1 x appe>s t ! heavily %ak5 localities are rang$ ^u l9es /amp$ out 9 ! relief1 ) ! mo/ sev]ely damag$ places at _! int]sections 7,fig4 #hc74 ,^! l9es ( exceptional in/ability are kn[n z seismotectonic l9es--e>?quake /ructure l9es4 ,illu/ration3 ,,fig4 #hc4--,seismotectonic l9es ( ! ,we/ ,indies4 ,! heavy %ocks above loose f\ndations4--,x is *>act]i/ic ( faults t !y soon bury !mselves f sight "u loose mat]ials1 & are ?us made difficult ( inspection4 ,! esc>pm5t :i* is ! direct consequ5ce ( a v]tical displacem5t ^u a fault t5ds to migrate f ! place ( its =mation1 r\nd+ ! surface z x does s & bury+ ! fault l9e b5ea? its deposits 7,fig4 #dc1 p4 #fj74 ,?is is n1 h[ev]1 ! sole reason :y loose f\ndations %\ld be places ( special dang] at ! "t ( e>? %ocks1 = ! reason t e>?quake waves are s5t out 9 all directions f ! surfaces ( displacem5t ?r\gh ! m$ium ( ! und]ly+ rock4 ,^! waves travel )9 ! firm rock = consid]able di/ances ) only a gradual dissipation ( _! en]gy1 b ) _! entry into ! loose surface deposits _! en]gy is quickly us$ up 9 local vibrations ( l>ge amplitude1 & h5ce de/ructive to build+s4 ,illu/ration3 ,,fig4 #hd4--;,device to illu/rate ! diff]5t effects ^u ! transmission & ! "* ( %ocks :i* are produc$ by firm rock & by loose mat]ials4 ,! ess5tial diff]5ce betwe5 firm rock & su* loose mat]ials z are f\nd ^u a riv] bottom or 9 ! 8made l&0 ab\t our cities may be illu/rat$ by ! simple device :i* is repres5t$ 9 ,fig4 #hd4 ,two simil> metal pans are susp5d$ f a firm support by b&s ( /eel & 8ela/ic0 braid ( simil> size & %ape1 & c>ry ea* a small block ( wood /&+ ^u its end4 ,simil> light bl[s are n[ adm9i/]$ directly to ! pans ) ! effect ( upsett+ t block :i* is support$ by ! loose braid because ( ! l>ge range or amplitude ( movem5t t is imp>t$ to ! pan4 ,! 8ela/ic0 braid1 because ( ^! l>ge vibrations ( :i* x is susceptible1 may repres5t ! loose mat]ials :5 an e>?quake wave passes into !m4 ,9 ! case ( ! /eel support1 ! en]gy ( ! bl[1 in/ead ( be+ dissipat$ 9 local sw++s ( ! pan1 is to a l>ge ext5t transmitt$ ?r\gh ! ela/ic metal to mat]ials beyond4 ,! /eel ?us resembles 9 its high ela/icity ! firm] rock basem5t1 :i* receives & transmits ! e>?quake %ocks1 b except :5 ruptur$ 9 a fault is subject to vibrations ( small amplitude only4 ,con/ruction 9 e>?quake regions4--,:]ev] e>?quakes h be5 felt1 !y are c]ta9 to occur aga92 & :]ev] m\nta9s are gr[+ or *anges ( level are 9 progress1 !re no record ( pa/ e>?quakes is requir$ 9 ord] to =eca/ ! future seismic hi/ory4 ,al?\gh ! future e>?quakes may be pr$ict$1 ! "t ( _! com+ is1 =tunately or un=tunately1 /ill hidd5 f u4 ,if "o's lot is to be ca/ 9 an e>?quake c\ntry1 ! only sane c\rse to pursue is to build ) due reg>d to future cont+5cies4 ,! dang]1 f de/ructive fires may to-day be l>gely met by me?ods ( con/ruction :i* levy an additional burd5 ( co/4 ,?\gh ! dang] f seismic di/urbances c h>dly be met z fully z t f fire1 yet x is true t build+s may be s con/ruct$ z to )/& all save ^? heavie/ %ocks 9 ! imm$iate vic9ity ( ! l9es ( l>ge displacem5t4 ,"h1 also1 a consid]able additional exp5se is involv$ 9 ! me?od ( con/ruction1 9 ! case ( resid5ces p>ticul>ly4 ,f :at has be5 said1 x is obvi\s t mu* ( ! dang] f e>?quakes c be met by a *oice ( site away f l9es ( important fracture & f areas ( relatively loose f\ndation4 ,! *oice ( build+ mat]ials is next ( importance4 ,^? build+s :i* succumb to e>?quakes are 9 mo/ cases rack$ or %ak5 ap>t1 & ?us !y become a prey to _! own inh]5t prop]ties ( in]tia4 ,ea* "p ( a /ructure may be reg>d$ z a weight :i* is balanc$ ^u a /iff rod & pivot$ ^u ! gr\nd4 ,:5 %ocks arrive1 ea* "p t5ds to be ?r[n into vibration aft] ! mann] ( an inv]t$ p5dulum4 ,9 proportion1 !re=e1 z ! weights are l>ge & re/ ^u long supports1 ! dang] ( ov]?r[ & ( te>+ ap>t is increas$4 ,9 g5]al1 /ructures are be/ con/ruct$ ( light mat]ials ^: weight is conc5trat$ ne> ! gr\nd4 ,masonry /ructures1 & especially high ones1 are1 !re=e1 ! lea/ suit$ = resi/+ e>?quakes1 ( :i* ! late complete de/ruction ( ! city ( ,mess9a is a grewsome rem9d]4 ,despite repeat$ w>n+s 9 ! pa/1 ! build+s ( t /rick5 city 7 g5]ally con/ruct$ ( heavy rubble1 :i* 9 addition _h be5 poorly cem5t$ 7,fig4 #di1 p4 #fg74 ,su* /ructures are usually fir/ ruptur$ at ! edges & corn]s1 s9ce "h ! vibrations :i* t5d to te> ! build+ asund] are resi/$ by no supports & are ren=c$ f neighbor+ walls4 ,illu/ration3 ,,fig4 #he4--;,h\se wreck$ 9 ,san ,francisco e>?quake ( #aijf because ! floors & p>titions 7 n securely fa/5$ to ! walls 7aft] ,r4 ,l4 ,humphrey74 ,an advantage ( ! fir/ importance is evid5tly secur$ if ! rods ( ! p5dulum1 ( :i* ! build+ is conceiv$ to be compos$1 h suffici5t ela/icity to be consid]ably di/ort$ )\t rupture & to aga9 recov] _! orig9al position4 ,?is is ! supreme advantage ( /ructural /eel = all l>ge build+s1 :i* is c\pl$1 h[ev]1 ) ! disadvantage t ! rivet$ fa/5+s are apt to be quickly %e]$ (f "u ! vibrations4 ,l>ge & high build+s1 :5 suffici5tly ela/ic1 h =tunately ! prop]ty ( de/roy+ ! e>? waves by int]f]5ce be=e !y h travel$ above ! l[] /ories4 ,= l>ge /ructures 9 :i* wood _c be us$1 /rongly ren=c$ concrete is well adapt$1 = x has 9 g5]al ! same advantages z /eel ) some:at r$uc$ ela/icity1 b ) a m effective b9d+ toge!r ( ! p>ts4 ,?is requirem5t ( ?or\gh brac+ & ty+ toge!r ( ! sev]al p>ts ( a build+ causes x to vibrate1 n z _m p5dulums1 b z "o body4 ,if met1 x removes l>gely ! dang] f rack+ /ra9s1 & = small /ructures p>ticul>ly x is ! requirem5t :i* is mo/ easily compli$ )4 ,= su* build+s x is !re=e necess>y t ! framework %\ld be built 9 a close network ) e jo9t firmly brac$ & ) all p>ts securely ti$ toge!r4 ,especial att5tion %\ld be giv5 to ! fa/5+s ( floor & p>tition ends4 ,! h\se %[n 9 ,fig4 #he c\ld n h be5 subject$ to heavy %ocks1 = ?\gh ! walls are ?r[n d[n1 ! floors & p>titions h be5 left ne> _! orig9al positions4 ,illu/ration3 ,,fig4 #hf4--;,build+ wreck$ at ,san ,mateo1 ,cali=nia1 dur+ ! late e>?quake4 ,! heavy ro( & upp] floor1 act+ z a unit1 h batt]$ d[n ! upp] walls 7aft] ,j4 ,c4 ,brann]74 ,?is t5d5cy ( ! walls1 floors1 p>titions1 & ro( to act z individual units 9 ! vibration1 is "o t mu/ be reckon$ ) & be met by specially effective brac+ & ty+ at ! junctions4 ,o!rwise ^! l>g] p>ts ( ! /ructure may act l batt]+ rams to ?r[ ov] ! walls or portions ( !m 7,fig4 #hf74 ,,read+ ,,ref]5ces ,,= ,,*apt]s ,,vii ,,& ,,viii ,g5]al works3-- ,,john ,,milne4 ,seismology4 ,london1 #ahih1 pp4 #cbj4 ,c4 ,e4 ,,dutton4 ,e>?quakes 9 ! ,light ( ! ,new ,seismology4 ,putnam1 ,new ,york1 #aijd1 pp4 #cad4 ,a4 ,,sieb]g4 ,h&bu* d] ,erdbeb5kunde4 ,brauns*weig1 #aijd1 pp4 #cfb4 ,,c\nt ,f4 ,,de ,,montessus ,,de ,,ballore4 ,les ,tremblem5ts de ,t]re1 ,gographie ,sismologique4 ,p>is1 #aijf1 pp4 #dge2 ,la ,sci5ce ,sismologique4 ,p>is1 #aijg1 pp4 #egi4 ,,william ,,h]b]t ,,hobbs4 ,e>?quakes1 an ,introduction to ,seismic ,geology4 ,appleton1 ,new ,york1 #aijg1 pp4 #ccf4 ,c4 ,g4 ,,knott4 ,! ,physics ( ,e>?quake ,ph5om5a4 ,cl>5don ,press1 ,ox=d1 #aijh1 pp4 #bhc4 ,e4 ,,rudolph4 ,ueb] ,subm>9e ,erdbeb5 und ,eruption51 ,beitrge zur ,geophysik1 vol4 #a1 #ahhg1 pp4 #acc-cfe2 vol4 #b1 #ahie1 pp4 #ecg-fff2 vol4 #c1 #ahih1 pp4 #bgc-ecf4 ,descriptive reports ( "s important e>?quakes3-- ,c4 ,e4 ,,dutton4 ,! ,*>le/on ,e>?quake ( ,augu/ #ca1 #ahhf1 #i? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhi1 pp4 #bjc-ebh4 ,b4 ,,kot4 ,on ! ,cause ( ! ,great ,e>?quake 9 ,c5tral ,japan1 #ahia1 ,j\r4 ,coll4 ,sci4 ,imp4 ,univ41 ,tokyo1 ,japan1 vol4 #e1 #ahic1 pp4 #bie-cec1 pls4 #bh-ce4 ,,john ,,milne & ,w4 ,k4 ,,burton4 ,! ,great ,e>?quake ( ,c5tral ,japan4 #ahia1 pp4 #aj1 pls4 #cj4 ,r4 ,d4 ,,oldham4 ,report on ! ,great ,e>?quake ( #ab? ,june1 #ahig1 ,mem4 ,geol4 ,surv4 ,india4 ,vol4 #bi1 #ahii1 pp4 #cgi1 pls4 #db4 ,a4 ,c4 ,,lawson1 & o!rs4 ,! ,cali=nia ,e>?quake ( ,april #ah1 #aijf1 ,report ( ! ,/ate ,e>?quake ,inve/igation ,commission1 ?ree qu>to vols4 7,c>negie ,in/itution ( ,wa%+ton72 _m plates & figures4 ,italian ,photographic ,society1 ,mess9a & ,reggio be=e & aft] ! ,e>?quake ( ,decemb] #bh1 #aijh 7an int]e/+ collection ( pictures74 ,flor5ce1 #aiji4 ,r4 ,s4 ,,t>r & ,l4 ,,m>t94 ,rec5t ,*anges ( ,level 9 ! ,yakutat ,bay ,region1 ,alaska1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ag1 #aijf1 pp4 #bi-fd1 pls4 #ab-bc4 ,,william ,,h]b]t ,,hobbs4 ,! ,e>?quake ( #ahgb 9 ! ,ow5s ,valley1 ,cali=nia1 ,beitrge zur ,geophysik1 vol4 #aj1 #aiaj1 pp4 #ceb-che1 pls1 #aj-bc4 ,faults 9 connection ) e>?quakes3-- ,,william ,h4 ,,hobbs4 ,on ,"s ,pr9ciples ( ,seismic ,geology1 ,beitrge zur ,geophysik1 vol4 #h1 #aijg1 ,*apt]s iv-v4 ,expansion or contraction ( ! e>?'s surface dur+ e>?quakes3-- ,,william ,h4 ,,hobbs4 ,a ,/udy ( ! ,damage to ,bridges dur+ ,e>?quakes1 ,j\r4 ,geol41 vol4 #af1 #aijh1 pp4 #fcf-fec2 ,! ,evolution & ! ,outlook ( ,seismic ,geology1 ,proc4 ,am4 ,phil4 ,soc41 vol4 #dh1 #aiji1 pp4 #bg-bi4 ,e>?quake con/ruction3-- ,,john ,,milne4 ,con/ruction 9 ,e>?quake ,c\ntries1 ,trans4 ,seis4 ,soc41 ,japan1 vol4 #ad1 #ahhi-ahij1 pp4 #a-bdf4 ,f4 ,,de ,,montessus ,,de ,,ballore4 ,l'art de btir dans les pays tremblem5ts de t]re 7#cd? ,congress ( ,fr5* ,ar*itects71 ,l',ar*itecture1 #aic ,anne1 #aijf1 pp4 #a-ca4 ,,gilb]t1 ,,humphrey1 ,,sewell1 & ,,s\l4 ,! ,san ,francisco ,e>?quake & ,fire ( ,april #ah1 #aijf1 & _! ,effects on ,/ructures & ,/ructural ,mat]ials1 ,bull4 #cbd1 ,u4 ,s4 ,geol4 ,surv41 #aijg1 pp4 #a-agj1 pls4 #a-eg4 ,,william ,h4 ,,hobbs4 ,con/ruction 9 ,e>?quake ,c\ntries1 ,! ,eng9e]+ ,magaz9e1 vol4 #cg1 #aiji1 pp4 #a-ai4 ,,lewis ,,ald5 ,,e/es4 ,e>?quake-pro( ,con/ruction1 a discussion ( ! effects ( e>?quakes on build+ con/ruction ) special ref]5ce to /ructures ( ren=c$ concrete1 publi%$ by ,truss$ ,concrete ,/eel ,company4 ,detroit1 #aiaa1 pp4 #df4 ,,*apt] ,,ix ,,! ,,rise ,,( ,,molt5 ,,rock ,,to ,,! ,,e>?',s ,,surface ,,volcanic ,,m\nta9s ,,( ,,exudation ,preval5t misconceptions ab\t volcanoes4--,! m or less common impression t a volcano is a 8burn+ m\nta90 or a 8smok+ m\nta90 has be5 mu* fo/]$ by ! s*ool texts 9 physical geography 9 use dur+ an e>li] p]iod4 ,! be/ introduction to a discussion ( volcanoes is1 !re=e1 a disillusionm5t f ?is notion4 ,f> f be+ burn+ or smok+1 !re is normally no combu/ion :atev] 9 connection ) a volcanic eruption4 ,! unsophi/icat$ t\ri/ :o1 look+ out f ,naples1 sees ! /eam cap :i* ov]hangs ! ,vesuvian crat] t+$ ) br[n1 easily receives ! impression t ! mat]ial ( ! cl\d is smoke4 ,ev5 m at night1 :5 a bright gl[ is reflect$ to 8 eye & soon fades away1 only to aga9 gl[ brightly aft] a few mom5ts h pass$1 is x difficult to remove ! impression t "o is wat*+ an int]mitt5t combu/ion )9 ! crat]4 ,! cl\d :i* floats away f ! cre/ ( ! m\nta9 is 9 reality compos$ ( /eam ) :i* is admix$ a l>g] or small] proportion ( f9e rock p[d] :i* gives to ! cl\d its br[ni% tone4 ,! gl[ obs]v$ at night is only a reflection f molt5 lava )9 ! crat]1 & ! v>iation ( its brightness is expla9$ by ! alt]nat+ rise & fall ( ! lava surface by a process pres5tly to be expla9$4 ,n only is !re no combu/ion 9 connection ) volcanic eruptions1 b s f> z ! volcano is a m\nta9 x is a product ( its own action4 ,! gr&e/ ( volcanic eruptions h produc$ no m\nta9s :atev]1 b only va/ pla9s or plateaus ( consolidat$ molt5 rock1 & e volcanic m\nta9 at "s "t 9 its hi/ory has ris5 out ( a relatively level surface4 ,:5 ! traditional notions ab\t volcanoes grew up1 x 0 suppos$ t ! solid e>? 0 m]ely a 8cru/0 envelop+ /ill molt5 mat]ial4 ,z has already be5 po9t$ out 9 an e>li] *apt]1 ?is view is no long] t5able1 = we n[ "k t ! condition ( matt] )9 ! e>?'s int]ior1 :ile p]haps n directly comp>able to any t is kn[n1 yet has prop]ties mo/ resembl+ kn[n matt] 9 a solid /ate2 x is mu* m rigid ?an ! be/ tool /eel4 ,:ile !re mu/ be res]voirs ( molt5 rock b5ea? active volcanoes1 x is none ! less cle> t !y are small1 local1 & tempor>y4 ,?is is %[n by ! comp>ative /udy ( volcanic outlets )9 any circumscrib$ di/rict4 ,x is p]haps n easy to frame a def9ition ( a volcano1 b its ess5tial "p1 in/ead ( be+ a m\nta91 is r a v5t or *annel :i* op5s up connection betwe5 a subsurface res]voir ( molt5 rock & ! surface ( ! e>?4 ,an eruption occurs :5ev] !re is a rise ( ?is mat]ial1 toge!r ) m or less /eam & admix$ gases1 to ! surface4 ,su* molt5 rock arriv+ at ! surface is designat$ lava4 ,! *anges 9 pressure ^u ?is mat]ial dur+ its elevation induce second>y ph5om5a z ! surface is approa*$1 & ^! manife/ations are (t5 mo/ awe inspir+4 ,:ile (t5 locally de/ructive1 ! geological importance ( su* ph5om5a is by reason ( _! t]rify+ aspect likely to be greatly exagg]at$4 ,e>ly views conc]n+ volcanic m\nta9s4--,z already po9t$ out1 a volcano at its bir? is n a m\nta9 at all1 b only1 s to speak1 a %aft or *annel ( communication betwe5 ! surface & a subt]ranean res]voir ( molt5 rock4 ,by br++ ?is melt$ rock to ! surface !re is built up a local elevation :i* may be designat$ a m\nta91 except :]e ! volume ( ! mat]ial is s l>ge & is spread to su* di/ances z to produce a pla9 7see fissure eruptions bel[74 ,9 ! e>ly hi/ory ( geology x 0 ! view ( ! great ,g]man geologi/ von ,bu* & 8 fri5d & colleague von ,humboldt1 t a volcanic m\nta9 0 produc$ 9 mu* ! same mann] z is a bli/] ^u ! body4 ,! fluids :i* pu% up ! cuticle 9 ! bli/] 7 "h replac$ by fluid rock :i* elevat$ ! s$im5t>y rock lay]s at ! surface into a dome or m\nd :i* 0 op5 at ! top--! s-call$ crat]4 ,?is 8elevation-crat]0 !ory ( volcanoes long held ! /age 9 geological sci5ce1 al?\gh x ignor$ ! v pat5t fact t ! lay]s on ! flanks ( volcanic cones are n ( s$im5t>y rock at all1 b1 on ! contr>y1 ( ! volcanic mat]ials :i* are br\ght up to ! surface dur+ ! eruption4 ,! obs]vational phase ( sci5ce 01 h[ev]1 dawn+1 & ! ,engli% geologi/s ,scrope & ,lyell 7 able to %[ by /udy ( volcanic m\nta9s t ! m\nd ab\t ! volcanic v5t 0 due to ! accumulation ( once molt5 rock :i* _h be5 ei!r exud$ or eject$4 ,mak+ use ( data d]iv$ f ,new ,zeal&1 ,scrope %[$ t1 in/ead ( be+ elevat$ dur+ ! =mation ( a volcanic m\nta91 ! s$im5t>y /rata ( ! vic9ity may be depress$ ne> ! volcanic v5t 7,fig4 #hg74 ,illu/ration3 ,,fig4 #hg4--;,brea*$ volcanic cone ne> ,auckl&1 ,new ,zeal&1 %[+ ! b5d+ d[n ( ! s$im5t>y /rata 9 ! neighborhood ( ! v5t 7aft] ,heaphy & ,scrope74 ,! bir? ( volcanoes4--,to confirm ! impression t ! =mation ( ! volcanic m\nta9 is 9 reality a second>y ph5om5on connect$ ) eruptions1 we may cite ! obs]v$ bir? ( a numb] ( volcanoes4 ,on ! #bj? ( ,septemb]1 #aech1 a new volcano1 s9ce kn[n z ,monte ,nuovo 7new m\nta971 rose on ! bord] ( ! anci5t ,lake ,lucr9us to ! we/w>d ( ,naples4 ,?is small m\nta9 atta9$ a height ( #ddj feet1 & is /ill to be se5 on ! %ore ( ! bay ( ,naples4 ,f ,mexico h be5 record$ ! bir?s ( sev]al new volcanoes3 ,jorullo 9 #agei1 ,po*utla 9 #ahgj1 & 9 #ahha a new volcano 9 ! ,ajusco ,m\nta9s ab\t midway betwe5 ! ,gulf ( ,mexico & ! ,pacific ,ocean4 ,! late/ ( new volcanoes is t rais$ 9 ,japan on ,novemb] #i1 #aiaj1 9 connection ) ! eruption ( ,usu-san4 ,?is 8,new ,m\nta90 rea*$ an elevation ( #fij feet4 ,illu/ration3 ,,fig4 #hh4--,view ( ! new ,camigu9 volcano f ! sea4 ,x 0 =m$ 9 #ahga ov] a ne>ly level pla94 ,! t[n ( ,cat>man appe>s at ! "r ne> ! %ore 7aft] an unpubli%$ photograph by ,pr(essor ,dean ,c4 ,worce/]74 ,z describ$ by von ,humboldt1 ,jorullo rose 9 ! night ( ! #bh? ( ,septemb]1 #agei1 f a fissure :i* op5$ 9 a broad pla9 at a po9t #ce miles di/ant f any !n exi/+ volcano4 ,! mo/ rem>kable ( new volcanoes rose 9 #ahga on ! isl& ( ,camigu9 nor?w>d f ,m9danao 9 ! ,philipp9e ar*ipelago4 ,?is m\nta9 0 visit$ by ! ,*all5g] exp$ition 9 #ahge1 & 0 fir/ asc5d$ & /udi$ ?irty ye>s lat] by a p>ty "u ! lead]%ip ( ,pr(essor ,dean ,c4 ,worce/]1 ! ,secret>y ( ! ,int]ior ( ! ,philipp9e ,isl&s1 to :om ! writ] is indebt$ = ?is description & ! accompany+ illu/ration ( ?is l>ge/ & mo/ int]e/+ ( new-born volcanoes4 ,z 9 ! case ( ,jorullo1 ! eruption began ) ! =mation ( a fissure 9 a level pla91 "s #djj y>ds di/ant f ! t[n ( ,cat>man 7,fig4 #hh74 ,! eruption cont9u$ = f\r ye>s1 at ! end ( :i* "t ! height ( ! summit 0 e/imat$ by ! ,*all5g] exp$ition to be #aijj feet4 ,at ! "t ( ! fir/ asc5t 9 #aije1 ! height 0 det]m9$ by an]oid z #agej feet1 ) %>p rock p9nacles project+ "s #ej or #ge feet high]4 ,active & ext9ct volcanoes4--,! t]ms 8active0 & 8ext9ct0 h come into m or less common use to describe respectively ^? volcanoes :i* %[ signs ( eruptive activity1 & ^? :i* are n at ! "t active4 ,! t]m 8dormant0 is appli$ to volcanoes rec5tly active & suppos$ to be 9 a d\btfully ext9ct condition4 ,f a well-kn[n volcano 9 ! vic9ity ( ,naples1 volcanoes :i* no long] erupt lava or c9d]1 b %[ gase\s emanations 7fum]oles7 are said to be 9 ! solfat>a condition1 or to %[ solfat>ic activity4 ,exp]i5ce %[s t ! t]m 8ext9ct01 :ile useful1 mu/ always be int]pret$ to mean app>5tly ext9ct4 ,?is may be illu/rat$ by ! hi/ory ( ,m\nt ,vesuvius1 :i* be=e ! ,*ri/ian era 0 =e/$ 9 ! crat] & %[$ no signs ( activity2 & 9 fact x is kn[n t = sev]al c5turies no eruption ( ! volcano _h tak5 place4 ,foll[+ a premonitory e>?quake felt 9 ! ye> #fc1 ! m\nta9 bur/ out 9 gr& explosive eruption 9 #gi ,a4,d4 ,?is eruption pr(\ndly alt]$ ! aspect ( ! m\nta9 & buri$ ! cities ( ,pompeii1 ,/abeii1 & ,h]culaneum f sight4 ,once m1 ?is "t dur+ ! middle ages1 = ne>ly five c5turies 7#aaci to #afca7 !re 0 complete inactivity1 if we except a light a% eruption 9 ! ye> #aejj4 ,dur+ ?is p]iod ( re/ ! crat] 0 aga9 =e/$1 b ! repose 0 sudd5ly t]m9at$ by "o ( ! gr&e/ eruptions 9 ! m\nta9's hi/ory4 ,illu/ration3 ,,fig4 #hi4--,map %[+ ! location ( ! belts ( active volcanoes4 ,! e>?'s volcano belts4--,! di/ribution ( volcanoes is n uni=m1 b1 on ! contr>y1 volcanic v5ts appe> 9 def9ite zones or belts1 ei!r ^u ! m>g9s ( ! cont95ts or includ$ )9 ! oceanic areas 7,fig4 #hi74 ,! mo/ important ( ^! belts girdles ! ,pacific ,ocean1 & is repres5t$ ei!r by *a9s or by m widely spac$ volcanic m\nta9s ?r\gh\t ! ,cordill]an ,m\nta9 sy/em ( ,s\? & ,c5tral ,am]ica & ,mexico1 by ! volcanoes ( ! ,coa/ & ,cascade ranges ( ,nor? ,am]ica1 ! fe/oon$ volcanic *a9 ( ! ,aleutian ,isl&s1 & ! simil> isl& arcs (f ! ea/]n coa/ ( ! ,eurasian cont95t4 ,! belt is fur!r cont9u$ ?r\gh ! isl&s ( ,malaysia to ,new ,zeal&1 & on ! ,pacific's s\!rn m>g9 are f\nd ! volcanoes ( ,victoria ,l&1 ,k+ ,edw>d ,l&1 & ,we/ ,ant>ctica4 ,illu/ration3 ,,fig4 #ij4--;,a portion ( ! 8fire girdle0 ( ! ,pacific1 %[+ ! relation ( ! *a9s ( volcanic m\nta9s to ! deeps ( ! neighbor+ ocean floor4 ,?is volcano girdle is by no means a p]fect "o1 = 9 addition to ! pr9cipal fe/oons ( ! we/]n bord] !re are _m second>y ones1 & /ill o!r arcs are f\nd well t[>d ! c5t] ( ! oceanic area4 ,ano!r broad belt ( volcanoes bord]s ! ,m$it]ranean ,sea1 & is ext5d$ we/w>d into ! ,atlantic ,ocean4 ,n>r[] belts are f\nd 9 bo? ! nor!rn & s\!rn portions ( ! ,atlantic ,ocean1 on ! m>g9s ( ! ,c>ibbean ,sea1 etc4 ,! fact ( greate/ significance 9 ! di/ribution seems to be t b&s ( active volcanoes are to be f\nd :]ev] m\nta9 ranges are p>allel$ by deeps on ! neighbor+ ocean floor 7,fig4 #ij74 ,z has be5 already po9t$ out 9 ! *apt] ^u e>?quakes1 x is j su* places z ^! :i* are ! seat ( e>?quakes2 ^! are zones ( ! e>?'s cru/ :i* are und]go+ ! mo/ rapid *anges ( level at ! pres5t "t4 ,?us ! rise ( ! l& 9 m\nta9s is proce$+ simultane\sly ) ! s9k+ ( ! sea floor to =m ! neighbor+ deeps4 ,illu/ration3 ,,fig4 #ia4--,volcanic cones =m$ 9 #aghc above ! ,skaptr fissure 9 ,icel& 7aft] ,hell&74 ,illu/ration3 ,,fig4 #ib4--;,diagrams to illu/rate ! location ( volcanic v5ts ^u fissure l9es1 a1 op5+s caus$ by lat]al movem5t ( fissure walls2 b1 op5+s =m$ at fissure int]sections4 ,arrangem5t ( volcanic v5ts along fissures & especially at _! int]sections4--,)9 ^? di/ricts 9 :i* volcanoes are widely sep>at$ f _! neighbors1 ! law ( _! arrangem5t is difficult to deciph]1 b ! view t volcanic v5ts are align$ ov] fissures is n[ support$ by s mu* evid5ce t illu/rations may be suppli$ f _m regions4 ,an exceptionally p]fect l9e ( small cones is f\nd along ! ,skaptr cleft 9 ,icel&1 ^u :i* /&s ! l>ge volcano ( ,laki4 ,?is fissure reop5$ 9 #aghc1 & great volumes ( lava 7 exud$4 ,ov] ! cleft !re 0 left a long l9e ( volcanic cones 7,fig4 #ia74 ,!re are 9 ,icel& two dom9at+ s]ies ( p>allel fissures ( ! same "* :i* take _! directions respectively nor!a/-s\?we/ & nor?-s\?4 ,_m su* fissures are traceable at ! surface z deep & ne>ly /raight clefts or gjs1 usually a few y>ds 9 wid?1 b ext5d+ = _m miles4 ,! ,eldgj has a l5g? ( m ?an #ah ,engli% miles & a dep? v>y+ f #djj to #fjj feet4 ,on "s ( ^! fissures no lava has ris5 to ! surface1 :]eas o!rs h at num]\s po9ts exud$ molt5 rock4 ,sometimes "o end only ( a fissure1 ! m widely gap+ portion1 has suppli$ ! conduits = ! molt5 lava4 ,?is is well illu/rat$ by ! crat]$ monticules rais$ by ! common ant ov] ! cracks :i* sep>ate ! blocks ( cem5t sidewalk1 ! hillocks be+ locat$ :]e ! mo/ favorable *annel 0 f\nd = ! elevation ( ! mat]ials4 ,illu/ration3 ,,fig4 #ic4--,outl9e map ( ! ea/]n portion ( ! isl& ( ,java1 display+ ! arrangem5t ( volcanic v5ts 9 alignm5t ^u fissures ) ! l>g] m\nta9s at fissure int]sections 7aft] ,v]beek74 ,^? places ^u fissures :i* become lava conduits appe> to be ! ones :]e ! cleft gapes wide/ s z to furni% ! wide/ *annel4 ,:]ev] a diff]5tial lat]al movem5t ( ! walls has occurr$1 op5+s w be f\nd 9 ! neighborhood ( ea* m9or v>iation f a /raight l9e 7,fig4 #ib;a74 ,:]ev] !re are two or m s]ies ( fissures1 & ?is w\ld appe> to be ! normal condition1 places favorable = lava conduits occur at fissure int]sections4 ,)9 su* v]itable volcano g>d5s z are to be f\nd 9 ,malaysia1 ! law ( volcano di/ribution became app>5t s soon z accurate maps _h be5 prep>$4 ,?us ! outl9e map ( a portion ( ! isl& ( ,java 7,fig4 #ic7 %[s u t :ile ! volcanoes ( ! isl& pres5t at fir/ sight a m or less irregul> b& or zone1 !re are a numb] ( fissures int]sect+ 9 a network1 & t ! volcanoes are align$ ^u ! fissures ) ! l>g] cones locat$ at ! int]sections4 ,s also 9 ,icel&1 ! great eruption ( ,askja 9 #ahge occurr$ at ! int]section ( two l9es ( fissure4 ,outside ^! closely pack$ volcanic regions1 simil> ?\gh less m>k$ networks are indicat$2 z1 = example1 9 & ne> ! ,gulf ( ,gu9ea4 ,if n[1 in/ead ( r$uc+ ! scale ( our volcano maps1 we increase x1 ! same law ( di/ribution is no less cle>ly br\ght out4 ,! monticules or small volcanic cones :i* =m ^u ! flanks ( l>g] volcanic m\nta9s are likewise built up ov] fissures :i* on num]\s occasions h be5 obs]v$ to op5 & ! cones to =m ^u !m4 ,illu/ration3 ,,fig4 #id4--,map ( ! ,puy ,p>i\ 9 ! ,auv]gne ( c5tral ,france4 ,! seat ( eruption has migrat$ along ! fissure ^u :i* ! e>li] cone _h be5 built up 7aft] ,scrope74 ,/ill fur!r r$uc+ n[ ! area ( our /udies & consid]+ = ! mom5t ! 8froz50 surface ( ! boil+ lava )9 ! caldron ( ,kilauea1 ?is :5 obs]v$ at night reveals 9 great p]fection ! sudd5 =mation ( fissures 9 ! cru/ ) ! appe>ance ( m9iature volcanoes ris+ successively at m or less regul> int]vals along !m4 ,x n infrequ5tly happ5s t aft] a volcanic v5t has become e/abli%$ above "s conduit 9 a fissure1 ! conduit migrates along ! fissure1 ?us e/abli%+ a new cone ) m or less complete de/ruction ( ! old "o 7,fig4 #id74 ,! s-call$ fissure eruptions4--,! gr&e/ ( all volcanic eruptions h be5 ^? 9 :i* ! entire l5g? & bread? ( ! fissures h be5 ! passageway = ! upwell+ lava4 ,su* gr&] eruptions h be5 = ! mo/ "p prehi/oric1 & 9 lat] geologic hi/ory h occurr$ *iefly 9 ,india1 9 ,abyss9ia1 9 nor?we/]n ,europe1 & 9 ! nor?we/]n ,unit$ ,/ates4 ,9 we/]n ,india ! s+ul>ly horizontal plateaus ( basaltic lava1 ! ,dekkan traps1 cov] "s #bjj1jjj squ>e miles & are m ?an a mile 9 dep?4 ,! und]ly+ basem5t :]e x appe>s ab\t ! m>g9s ( ! basalt is 9 _m places int]sect$ by dikes or fissure fill+s ( ! same mat]ial4 ,no cones or def9ite v5ts h be5 f\nd4 ,illu/ration3 ,,fig4 #ie4--;,basaltic plateau ( ! nor?we/]n ,unit$ ,/ates due to fissure eruptions ( lava4 ,! l>g] portion ( ! nor?we/]n ,briti% ,isles w\ld appe> to h be5 at "o "t simil>ly blanket$ by ne>ly horizontal b$s ( basaltic lava1 :i* b$s ext5d$ nor?we/w>d across ! sea ?r\gh ! ,orkney & ,f>oe isl&s to ,icel&4 ,remnants ( ?is va/ plateau are to-day f\nd 9 all ! isl& gr\ps z well z 9 l>ge areas ( nor!a/]n ,irel&1 & fissure fill+s ( ! same mat]ial occur ?r\gh\t l>ge areas ( ! ,briti% ,isles4 ,9 _m cases ^! dikes repres5t once molt5 rock :i* may nev] h communicat$ ) ! surface at ! "t ( ! lava outp\r+1 yet !y well illu/rate :at we might expect to f9d if ! basalt %eets ( ,icel& or ,irel& 7 to be remov$4 ,! floods ( basaltic lava :i* 9 ! nor?we/]n ,unit$ ,/ates h yield$ ! b>r5 plateau ( ! ,cascade ,m\nta9s 7,fig4 #ie7 w\ld appe> to (f] ano!r example ( fissure eruption1 ?\gh cones appe> ^u ! surface & p]haps indicate ! position ( lava outlets dur+ ! lat] phases ( ! eruptive p]iod4 ,! b>r5ness & desolation ( ^! lava pla9s is sugge/$ by ,fig4 #if4 ,illu/ration3 ,,fig4 #if4--,lava pla9s ab\t ! ,snake ,riv] 9 ,idaho4 ,?\gh ! great] effusions ( lava h occurr$ 9 prehi/oric times1 & ! mann] ( extrusion has necess>ily be5 l>gely inf]r$ f ! imm5se volume ( ! exud$ mat]ials & ! exi/5ce ( basaltic dikes 9 neighbor+ regions1 yet 9 ,icel& we are able to obs]ve ! connection betwe5 ! dikes & ! lava outfl[s4 ,pr(essor ,?orodds5 has /at$ t 9 ! great basaltic plateau ( ,icel&1 lava has well$ out quietly f ! :ole l5g? ( fissures & (t5 on bo? sides )\t giv+ rise to ! =mation ( cones4 ,at ?ree wid] portions ( ! great ,eld cleft1 lava well$ out quietly )\t ! =mation ( cones1 ?\gh "h 9 ! s\!rn prolongation ( ! fissure1 :]e x 0 n>r[]1 a r[ ( l[ slag cones appe>$4 ,:]e ! lava outwell+s occurr$1 an area ( #bgj squ>e miles 0 flood$4 ,illu/ration3 ,,fig4 #ig4--;,*>act]i/ic pr(iles ( lava volcanoes4 #a1 basaltic lava m\nta92 #b1 m\nta9 ( silice\s lava 7aft] ,judd74 ,! composition & ! prop]ties ( lava4--,9 our /udy ( igne\s rocks 7,*apt] ,,iv7 x 0 le>n$ t !y are compos$ = ! mo/ "p ( silicate m9]als1 & t 9 _! *emical composition !y repres5t v>i\s proportions ( silica1 alum9a1 iron1 magnesia1 lime1 pota%1 & soda4 ,! m abundant ( ^! con/itu5ts is silica1 :i* v>ies f #ce to #gj p] c5t ( ! :ole4 ,:5ev] ! cont5t ( silica is relatively l[1--basic or basaltic lava1--! cool$ rock is d>k 9 color & relatively heavy4 ,x melts at a relatively l[ temp]ature1 & is 9 consequ5ce relatively fluid at ! temp]atures :i* lavas usually h on rea*+ ! e>?'s surface4 ,fur!rmore1 f be+ m fluid1 ! wat] :i* is ne>ly always pres5t 9 l>ge quantity )9 ! lava m readily makes its escape ^u rea*+ ! surface4 ,eruptions ( su* lava are = ?is reason )\t ! viol5t aspects :i* belong to extrusions ( m silice\s 7m 8acidic07 lavas4 ,= ! same reason1 also1 basaltic lava fl[s m freely & c spread mu* f>!r be=e x has cool$ suffici5tly to consolidate4 ,?is is equival5t to say+ t its surface w assume a flatt] angle ( slope1 :i* 9 ! case ( basaltic lava seldom exce$s t5 degrees & may be less ?an "o degree 7,fig4 #ig74 ,illu/ration3 ,,fig4 #ih4--;,a driblet cone 7aft] ,j4 ,d4 ,dana74 ,silice\s lavas1 on ! o!r h&1 are1 :5 consolidat$1 relatively light bo? 9 color & weight & melt at relatively high temp]atures4 ,!y are1 !re=e1 usually b p>tly fus$ & ( a visc\s consi/5cy :5 !y arrive at ! e>?'s surface4 ,because ( ?is viscosity !y (f] mu* resi/ance to ! lib]ation ( ! conta9$ wat]1 :i* !re=e is releas$ only to ! accompanim5t ( m or less viol5t explosions4 ,! lava is bl[n into ! air & usually falls z consolidat$ fragm5ts ( v>i\s degrees ( co>s5ess4 ,illu/ration3 ,,fig4 #ii4--,view ( ,leff+well crat]1 a c9d] cone 9 ! ,ow5s valley1 ,cali=nia 7aft] an unpubli%$ photograph by ,w4 ,d4 ,johnson74 ,x mu/ n1 h[ev]1 be assum$ t ! temp]ature ( lava is always ! same :5 x arrives at ! surface1 & h5ce x may happ5 t a silice\s lava is exud$ at s high a temp]ature t x behaves l a normal basaltic lava4 ,on ! o!r h&1 basaltic lavas may be extrud$ at unusually l[ temp]atures1 9 :i* case _! behavior may resemble t ( ! normal silice\s lavas4 ,if1 h[ev]1 z is g5]ally ! case1 ! en]gy ( explosion ( a basaltic lava is relatively small1 any eject$ portions ( ! liquid lava travel to a mod]ate height only 9 ! air1 s t on fall+ !y are /ill suffici5tly pa/y to adh]e to rock surfaces & ?us build up ! rem>kably /eep cones & sp9es kn[n z 8spatt] cones0 or 8driblet cones0 7,fig4 #ih74 ,:51 on ! o!r h&1 ! en]gy ( explosion is great1 z is normally ! case ) silice\s lavas1 ! portions ( eject$ lava h be5 fully consolidat$ be=e _! fall to ! surface1 s t !y build up ! same type ( accumulation z w\ld s& fall+ 9 ! same mann]4 ,! /ructures :i* !y =m are kn[n z tuff1 c9d]1 or a% cones 7,fig4 #ii74 ,:5ev] ! conta9$ wat] passes (f f silice\s lavas )\t viol5t explosions1 ! lava may fl[ f ! v5t1 b 9 contra/ to basaltic lavas x travels a %ort di/ance only be=e consolidat+4 ,! result+ m\nta9 is 9 consequ5ce proportionately high & /eep 7,fig4 #ig74 ,eruptions *>act]iz$ by viol5t explosions accompani$ by a fall ( c9d] are describ$ z explosive eruptions4 ,^? :i* are relatively quiet1 & 9 :i* ! *ief product is 9 ! =m ( /reams ( fl[+ lava1 are spok5 ( z convulsive eruptions4 ,! ?ree ma9 types ( volcanic m\nta94--,if ! eruptions at a volcanic v5t are exclusively ( ! explosive type1 ! mat]ial ( ! m\nta9 :i* results is ?r\gh\t tuff or c9d]1 & ! volcano is describ$ z a c9d] cone4 ,if1 on ! o!r h&1 ! v5t at e eruption exudes lava1 a m\nta9 ( solid rock results :i* is a lava dome4 ,x is1 h[ev]1 ! exception = a volcano :i* has a long hi/ory to manife/ b a s+le k9d ( eruption4 ,at "o "t exud+ lava comp>atively quietly1 at ano!r ! viol5ce ) :i* ! /eam is lib]at$ yields only c9d]1 & ! m\nta9 is a composite ( ! two mat]ials & is kn[n z a composite volcanic cone4 ,! lava dome4--,:5 successive lava fl[s come f a crat]1 ! /ructure :i* results has ! =m ( a m or less p]fect dome4 ,if ! lava be ( ! basaltic or fluid type1 ! slopes are flat1 seldom mak+ an angle ( z mu* z t5 degrees ) ! horizon & flatt] t[>d ! summit 7,fig4 #aja1 p4 #ajf74 ,if ( silice\s or visc\s lava1 on ! o!r h&1 ! slopes are correspond+ly /eep & 9 "s cases precipit\s4 ,to ?is latt] class belong "s ( ! ,kupp5 ( ,g]many1 ! puys ( c5tral ,france1 & ! mamelons ( ! ,isl& ( ,b\rbon4 ,illu/ration3 ,,fig4 #ajj4--,map ( ,hawaii & ! lava volcanoes ( ,mokuawe[eo 7,mauna ,loa7 & ,kilauea 7aft] ! gov]nm5t map by ,alex&]74 ,! basaltic lava domes ( ,hawaii4--,at ! 8crossroads ( ! ,pacific0 rises a d\ble l9e ( lava volcanoes :i* rea* f #bj1jjj to #cj1jjj feet above ! floor ( ! ocean1 "s ( !m among ! gr&e/ volcanic m\nta9s t are kn[n4 ,m ?an half ! height & a mu* l>g] proportion ( ! bulk ( ! l>ge/ ( ^! are hidd5 b5ea? ! ocean's surface4 ,! two great active v5ts are ,mokuawe[eo 7on ,mauna ,loa7 & ,kilauea1 di/9ct volcanoes not)/&+ ! fact t _! lava extravasations h be5 m]g$ 9 a s+le mass4 ,! rim ( ! crat] ( ,mauna ,loa is at an elevation ( #ac1fge feet above ! sea1 :]eas t ( ,kilauea is less ?an #djjj feet & appe>s to re/ ^u ! flank ( ! l>g] m\nta9 7,figs4 #ajj & #aja74 ,al?\gh "o crat] is b #bj miles di/ant f ! o!r & ne>ly #aj1jjj feet l[]1 _! eruptions h app>5tly be5 unsympa!tic4 ,n[h]e h /ill active lava m\nta9s be5 subject$ to su* frequ5t obs]vations ext5d+ ?r\gh\t a long p]iod1 & ! dynamics ( _! eruptions are fairly well und]/ood4 ,to put ?is be=e ! read]1 x w be be/ to consid] bo? m\nta9s1 = ?\gh !y h mu* 9 common1 ! obs]vations f "o are /rangely complem5t>y to ^? ( ! o!r4 ,! l[] crat] be+ easily accessible1 ,kilauea has be5 (t5 visit$1 & !re exi/s a long s]ies ( m or less consecutive obs]vations ^u x1 :i* h be5 assembl$ & /udi$ by ,dana & ,hit*cock4 ,! place ( outfl[ ( ! ,kilauea lavas has n g5]ally be5 visible1 :]eas ,mokuawe[eo has slopes ris+ ne>ly #ad1jjj feet above ! sea & displays ! records ( outfl[ ( _m eruptions1 "s ( :i* 7 accompani$ by ! gr&e/ ( volcanic ph5om5a4 ,illu/ration3 ,,fig4 #aja4--,section ?r\gh ,mauna ,loa & ,kilauea4 ,lava movem5ts )9 ! caldron ( ,kilauea4--,! crat]s ( ^! m\nta9s are ! l>ge/ ( active ones1 ea* be+ 9 excess ( sev5 miles 9 circumf]5ce4 ,9 %ape !y are irregul>ly elliptical & consi/ ( a s]ies ( /eps or t]races desc5d+ to a pit at ! bottom1 9 :i* are op5 lakes ( boil+ lava4 ,en\gh is kn[n ( ! hi/ory ( ,kilauea to /ate t ! /eep cliffs b\nd+ ! t]races are fault walls produc$ by inbreak ( a froz5 lava surface4 ,! cliff bel[ ! s-call$ 8black l$ge0 0 produc$ by ! fall+ 9 ( ! froz5 lava surface at ! "t ( ! outfl[ ( #ahdj1 ! lava issu+ ^u ! ea/]n flank ( ! m\nta9 & p\r+ into ! sea ne> ,nanawale4 ,s9ce t date ! floor ( ! pit bel[ ! level ( ?is l$ge has be5 ess5tially a movable plat=m ( froz5 lava ( unkn[n & d\btless v>iable ?ickness :i* has ris5 & desc5d$ l ! floor ( an elevator c> betwe5 its guid+ ways 7,fig4 #ajb74 ,! floor has1 h[ev]1 nev] be5 complete1 = "o or m op5 lakes are always to be se51 t ( ,halemaumau locat$ ne> ! s\?we/]n m>g9 hav+ be5 mu* ! mo/ p]si/5t4 ,)9 ! op5 lakes ! boil+ lava is app>5tly :ite hot at ! dep? ( b a few in*es bel[ ! surface1 & 9 ! ov]turn+s ( ! mass ^! hott] portions are br\ght to ! surface & appe> z :ite /reaks m>k+ ! r$d] surface portions4 ,f "t to "t ! surface freezes ov]1 !n cracks op5 & erupt at favor$ po9ts along ! fissures1 s5d+ up jets & f\nta9s ( lava1 ! mat]ial ( :i* falls 9 pa/y fragm5ts t build up driblet cones4 ,small fluid clots are %ot out1 c>ry+ a ?readlike l9e ( lava glass beh9d !m1 ! well-kn[n 8,pel's hair40 ,sometimes ! op5 lakes build up congeal$ walls1 ris+ above ! g5]al level ( ! pit1 & f _! rim ! lava spills ov] 9 cascades to spread out ^u ! froz5 floor1 ?us increas+ its ?ickness f above 7,fig4 #ajc74 ,at o!r times a great dome ( lava has be5 pu%$ up f ! pit ( ,halemaumau "u a froz5 %ell1 ! molt5 lava %9+ r$ ?r\gh cracks 9 its surface & exud+ s z to heal ea* widely op5$ fissure z x =ms4 ,illu/ration3 ,,fig4 #ajb4--,s*ematic diagram to illu/rate ! mov+ plat=m ( froz5 lava :i* rises & falls 9 ! crat] ( ,kilauea4 ,at int]vals ( f a few ye>s to n9e or t5 ye>s ! crat] has be5 p]iodically dra9$1 at :i* times ! mov+ plat=m ( froz5 lava has sunk m or less rapidly to levels f> bel[ ! black l$ge & f #ijj to #agjj feet bel[ ! crat] rim4 ,foll[+ ?is desc5t a sl[ progressive rise is inaugurat$1 :i* has sometimes gone on at a rate ( m ?an a hundr$ feet p] ye>1 ?\gh x is usually mu* sl[] ?an ?is4 ,:5 ! plat=m has rea*$ a height v>y+ f #gjj to #cej feet bel[ ! crat] rim1 ano!r sudd5 settlem5t occurs :i* aga9 c>ries ! pit floor d[nw>d a di/ance ( f #cjj to #gjj feet4 ,illu/ration3 ,,fig4 #ajc4--,view ( ! op5 lava lake ( ,halemaumau )9 ! crat] ( ,kilauea1 ! molt5 lava %[n cascad+ ov] ! rais$ lava walls on to ! floor ( ! pit 7aft] ,pavl[74 ,! dra9+ ( ! lava caldrons4--,! *anges :i* g on )9 ! crat] ( ,mokuawe[eo1 ?\gh less /udi$ ?an ^? ( ,kilauea1 appe> to be 9 "s respects diff]5t4 ,"h e eruption seems to be prec$$ by a m or less rapid influx ( melt$ lava to ! pit ( ! crat]1 ?is ph5om5on be+ obs]v$ f a di/ance z a brilliant light above ! crat]--! reflection ( ! gl[ f ov]hang+ vapor cl\ds4 ,! upris+ ( ! lava has (t5 be5 accompani$ by ! =mation ( high lava f\nta9s ^u ! surface1 & ! molt5 lava sometimes appe>s 9 fissures ne> ! crat] rim at levels well above ! lava surface )9 ! pit4 ,al?\gh 9 _m cases ! lava :i* has ?us flood$ ! crat] has sudd5ly dra9$ away )\t aga9 becom+ visible1 x is probable t 9 su* cases an outlet has be5 f\nd to "s subm>9e exit1 s9ce "u-ocean dis*>ge effects h be5 obs]v$ 9 connection ) eruptions ( ea* ( ! volcanoes4 ,illu/ration3 ,,fig4 #ajd4--,map %[+ ! mann] ( outfl[ ( lava f ,kilauea dur+ ! eruption ( #ahdj4 ,! outfl[+ lava made its appe>ance successively at ! po9ts ,a1 ,b1 ,c1 m1 n1 & f9ally at a po9t bel[ n1 f :5ce x issu$ 9 volume & fl[$ d[n to ! sea at ,nanawale 7aft] ,j4 ,d4 ,dana74 ,inasmu* z no e>?quakes are felt 9 connection ) su* outfl[s z h be5 describ$1 x is probable t ! hot lava fuses a passageway = itself into "s op5 *annel und]nea? ! flanks ( ! m\nta94 ,su* a c\rse is well illu/rat$ by ! outfl[ ( ,kilauea 9 #ahdj1 :51 x w be rememb]$1 occurr$ ! great d[n-plunge ( ! crat] t yield$ ! pit bel[ ! black l$ge4 ,at ?is "t ! lava fir/ made its appe>ance ^u ! flanks ( ! m\nta9 at ! bottom ( a small pit or inbreak crat] :i* op5$ five miles s\!a/ ( ! ma9 crat] ( ,kilauea 7,fig4 #ajd74 ,)9 ?is new crat] ! lava rose1 & small ejections soon foll[$ f fissures =m$ 9 its neighborhood4 ,"s "t aft]1 ! lava sank 9 ! fir/ new crat]1 only to reappe> successively at o!r small op5+s 7,fig4 #ajd1 ,b1 ,c1 m1 n7 & f9ally to issue 9 volume at a po9t elev5 miles f ! %ore & fl[ !reaft] ^u ! surface ( ! m\nta9 until x _h rea*$ ! sea4 ,only ! slighte/ e>? tremors 7 felt1 & z no rumbl+s 7 he>d1 x is evid5t t ! lava fus$ its way along a buri$ *annel l>gely op5 at ! "t 7see bel[1 p4 #aab74 ,9 a majority ( ! eruptions ( ,mokuawe[eo1 :5 ! outfl[+ lavas h become visible1 ! molt5 rock has app>5tly fus$ its way out to ! surface ( ! m\nta9 at po9ts f #ajjj to #cjjj feet bel[ ! bottom ( ! crat]1 & ?is dis*>ge has correspond$ 9 "t to ! l[]+ ( ! lava surface )9 ! crat]4 ,!re are1 h[ev]1 ?ree in/ances ^u record 9 :i* ! lava issu$ f def9ite r5ts :i* 7 =m$ ^u ! m\nta9 flanks at comp>atively l[ levels4 ,9 contra/ to ! =mation ( fus$ outlets1 ^! ruptures ( a portion ( ! m\nta9's flank 7 always accompani$ by vigor\s local e>?quakes ( %ort duration4 ,9 "o in/ance 7! eruption ( #ahea7 su* a r5t appe>$ "u ! same conditions b at an elevation ( #ab1ejj feet1 or ne> ! level ( ! lava 9 ! crat]4 ,! outfl[ ( ! lava floods4--,9 ord] to prop]ly compreh5d ^! & _m o!rwise puzzl+ ph5om5a connect$ ) volcanoes1 x is necess>y to keep ev] 9 m9d ! q rem>kable heat-insulat+ prop]ty ( congeal$ lava4 ,s soon z a ?9 cru/ has =m$ ^u ! surface ( molt5 rock1 ! heat ( ! und]ly+ fluid mass is giv5 (f ) extreme sl[ness1 s t lava /reams no long] connect$ ) _! int]nal lava res]voirs may rema9 molt5 = decades4 ,illu/ration3 ,,fig4 #aje4--,lava ( ,matavanu ^u ! ,isl& ( ,savaii fl[+ d[n to ! sea dur+ ! eruption ( #aijf4 ,! c\rse may be foll[$ by ! jets ( /eam escap+ f ! surface d[n to ! great /eam cl\d :i* rises :]e ! fluid lava dis*>ges into ! sea 7aft] ,h4 ,i4 ,j5s574 ,we h se5 t = ,mokuawe[eo & ,kilauea1 lava ei!r quietly melts its way to ! surface at ! "t ( outfl[1 or else produces a r5t = its egress to ! accompanim5t ( vigor\s local e>?quakes4 ,9 ei!r case if ! lava issues at a po9t f> bel[ ! crat]1 gigantic lava f\nta9s arise at ! po9t ( outfl[1 ! fluid rock %oot+ up to heights :i* range f #bej to #fjj or m feet above ! surface4 ,a c]ta9 proportion ( ?is fluid lava is suffici5tly cool$ to consolidate :ile travel+ 9 ! air1 & fall+1 x builds up a c9d] cone :i* is left z a location monum5t = ! place ( dis*>ge4 ,f ?is outlet ! molt5 lava beg9s its j\rney d[n ! slope ( ! m\nta91 & quickly freezes ov] to produce a tunnel1 b5ea? ! ro( ( :i* ! fluid lava fl[s ) comp>atively sl[ fur!r loss ( heat4 ,save = occasional /eam jets issu+ f its surface1 x may give little indication ( its pres5ce until x has rea*$ ! sea 7,fig4 #aje74 ,illu/ration3 ,,fig4 #ajf4--,lava /ream dis*>g+ into ! sea f b5ea? ! froz5 ro( ( a lava tunnel4 ,eruption ( ,matavanu on ,savaii 9 #aijf 7aft] ,sapp]74 ,if suffici5t 9 volume & ! %ore be n too di/ant1 ! /ream ( lava arrives at ! sea1 :]e1 dis*>g+ f ! m\? ( its tunnel1 x ?r[s up va/ volumes ( /eam & induces ebullition ( ! wat] ov] a wide area 7,fig4 #ajf74 ,pr(essor ,dana1 :o visit$ ,hawaii a few mon?s only aft] ! great outfl[ ( #ahdj1 /ates t ! lava1 ^u rea*+ ! ocean1 0 %iv]$ l melt$ glass & ?r[n up 9 millions ( p>ticles :i* d>k5$ ! sky & fell l hail ov] ! surr\nd+ c\ntry4 ,! light 0 s bright t at a di/ance ( =ty miles f9e pr9t c\ld be read at midnight4 ,illu/ration3 ,,fig4 #ajg4--;,diagrammatic repres5tation ( ! /ructure ( ! flanks ( lava volcanoes z a result ( ! dra9+ ( froz5 lava /reams4 ,protect$ f any ext5sive consolidation by its congeal$ cov]1 ! lava )9 a /ream may all dra9 away1 leav+ beh9d an empty lava tunnel1 :i* 9 ! case ( ! ,hawaiian volcanoes sometimes has its ro( hung ) beautiful lava /alactites & its floor /udd$ ) ?9 lava sp9es4 ,lat] lava outfl[s ov] ! same or neighbor+ c\rses bury su* tunnels b5ea? o!rs ( simil> nature1 giv+ to ! m\nta9 flanks an elongat$ cellul> /ructure illu/rat$ s*ematically 9 ,fig4 #ajg4 ,^! buri$ *annels may 9 ! future be aga9 utiliz$ = outfl[s simil> 9 "* to t ( ,kilauea 9 #ahdj4 ,illu/ration3 ,,fig4 #ajh4--;,diagram to %[ ! mann] ( =mation ( mesas or table m\nta9s by ! outfl[ ( lava 9 valleys & ! subsequ5t m rapid erosion ( ! int]v5+ ridges4 ,r1 e>li] riv] valley2 ,r',r'1 lat] valleys4 ,:ile ! =mation ( lava /alactites ( su* p]fection & beauty is peculi> to ! ,hawaiian lava tunnels1 ! =mation ( ! tunnel 9 connection ) lava outfl[ is ! rule :]ev] a dissipation at ! end has p]mitt$ ( dra9age4 ,a few h\rs only aft] ! fl[ has begun1 ! froz5 surface has usually a ?ickness ( a few in*es1 & ?is cov] may be walk$ ov] ) ! lava /ill molt5 bel[4 ,at fir/ 9 "p support$ by ! molt5 lava1 ! tunnel ro( sometimes caves 9 s soon z dra9age has occurr$4 ,illu/ration3 ,,fig4 #aji4--,surface ( lava ( ! ,pahoehoe type4 ,:]ev] basaltic lava has spread out 9 valleys on ! surface ( m easily erod$ mat]ial1 ei!r c9d] or s$im5t>y =mations1 ! s(t] int]v5+ ridges are fir/ c>ri$ away by ! erod+ ag5cies1 leav+ ! lava z capp+s ^u residual elevations4 ,?us are d]iv$ a type ( table m\nta9 or mesa ( ! sort well illu/rat$ ^u ! we/]n slopes ( ! ,si]ra ,nevadas 9 ,cali=nia 7,fig4 #ajh74 ,illu/ration3 ,,fig4 #aaj4--,?ree successive views to illu/rate ! gr[? ( ! ,isl& ( ,savaii f ! outfl[ ( lava at ,matavanu 9 ! ye> #aijf4 a1 ne> ! beg9n+ ( ! outfl[2 b1 "s weeks lat] ?an a2 c1 "s weeks lat] ?an b 7aft] ,h4 ,i4 ,j5s574 ,! surface :i* fl[+ lava assumes1 :ile subject to consid]able v>iation1 may yet be classifi$ into two r di/9ct types4 ,on ! "o h& !re is ! bill[y surface 9 :i* ellipsoidal or kidney-%ap$ masses1 ea* ) dim5sions ( f "o to sev]al feet1 lie m]g$ 9 "o ano!r1 n unlike an irregul> collection ( s(a pill[s4 ,?is type ( lava has become kn[n z ! ,pahoehoe1 f ! ,hawaiian occurr5ce 7,fig4 #aji74 ,a v>iation f ?is type is ! 8cord$0 or 8ropy0 lava1 ! surface ( :i* mu* resembles rope z x is coil$ along ! deck ( a vessel1 ! coils be+ "h ! l9es ( scum or scori arrang$ 9 ?is mann] by ! curr5ts at ! surface ( ! /ream 7,fig4 #abc1 p4 #abd74 ,a q diff]5t type is ! block lava 7,aa type7 :i* usually has a ragg$ scoriace\s surface & consi/s ( m or less sep>ate fragm5ts ( cool$ lava 7,fig4 #aca1 p4 #acj74 ,:]ev] lava fl[s into ! sea 9 quantity1 x ext5ds ! m>g9 ( ! %ore1 (t5 by consid]able areas4 ,! outfl[ ( ,kilauea 9 #ahdj ext5d$ ! %ore ( ,hawaii outw>d = ! di/ance ( a qu>t] ( a mile1 & a m rec5t illu/ration ( su* ext5sion ( l& masses is furni%$ by ,fig4 #aaj4 ,,*apt] ,x ,,! ,,rise ,,( ,,molt5 ,,rock ,,to ,,! ,,e>?',s ,,surface ,,volcanic ,,m\nta9s ,,( ,,eject$ ,,mat]ials ,! me*anics ( crat] explosions4--,if we n[ turn f ! lava volcano to ! active c9d] cone1 we enc\nt] an entire *ange ( sc5e4 ,9 place ( ! quiet fl[ & convulsive movem5ts ( ! molt5 lava1 we "h meet ) repeat$ explosions ( great] or less viol5ce4 ,if we are to pr(itably /udy ! mann] ( ! explosions1 consid]+ ! volcanic v5t z a great exp]im5tal app>atus1 x w\ld be well to select = our purpose a volcano :i* is 9 a n too viol5t mood4 ,! well-kn[n c9d] cone ( ,/romboli 9 ! ,eolian gr\p ( isl&s nor? ( ,sicily has1 ) %ort & unimportant int]ruptions1 rema9$ 9 a /ate ( light explosive activity s9ce ! beg9n+ ( ! ,*ri/ian era4 ,ris+ z x does "s ?ree ?\s& feet directly out ( ! ,m$it]ranean1 & display+ by day a :ite /eam cap & an int]mitt5t gl[ by night1 its summit c be se5 = a di/ance ( a hundr$ miles at sea & x has ju/ly be5 call$ ! 8,ligh?\se ( ! ,m$it]ranean40 ,! 8fla%0 int]val ( ?is beacon may v>y f "o to tw5ty m9utes1 & x may %[1 fur!rmore1 consid]able v>iation ( int5sity4 ,= ! reason t ! crat] ( ! m\nta9 is locat$ at "o side & at a consid]able di/ance bel[ ! actual summit1 ! opportunity "h af=d$ ( look+ into ! crat] is mo/ favorable :5ev] ! direction ( ! w9d is su* z to pu% aside ! ov]hang+ /eam cl\d 7,fig4 #aaa74 ,long ago ! ,italian vulcanologi/ ,spallanzani und]took to make obs]vations f above ! crat]1 & _m o!rs s9ce 8 day h pr(it$ by 8 example4 ,)9 ! crat] ( ! volcano !re is se5 a lava surface lightly froz5 ov] & trav]s$ by _m cracks f :i* vapor jets are issu+4 ,"h1 z 9 ! ,kilauea crat]1 !re are op5 pools ( boil+ lava4 ,f "s ( ^!1 lava is se5 well+ out to ov]fl[ ! froz5 surface2 f o!rs1 /eam is eject$ 9 puffs z ?\gh f ! /ack ( a locomotive4 ,)9 o!rs lava is se5 heav+ up & d[n 9 viol5t ebullition1 & at int]vals a great bubble ( /eam is eject$ ) explosive viol5ce1 c>ry+ up ) x a consid]able quantity ( ! /ill molt5 lava1 toge!r ) its scumlike surface1 to fall outside ! crat] & rattle d[n ! m\nta9's slope into ! sea4 ,foll[+ ?is explosion ! lava surface 9 ! pool is l[]$ & ! agitation is r5ew$1 to culm9ate aft] ! fur!r lapse ( a few m9utes 9 a second explosion ( ! same nature4 ,! rise ( ! lava :i* prec$es ! ejection appe>s at night z a bright] reflection or gl[ f ! ov]hang+ /eam cl\d--! fla% se5 by ! m>9] f 8 vessel4 ,illu/ration3 ,,fig4 #aaa4--,! volcano ( ,/romboli1 %[+ ! exc5tric position ( ! crat] 7aft] a sket* by ,judd74 ,:at is go+ on )9 ! crat] ( ,/romboli we may p]haps be/ illu/rate by ! boil+ ( a /iff porridge ov] a hot fire4 ,any "o :o has made corn mu% ov] a hot camp fire is fully aw>e t 9 proportion z ! mu% becomes ?ick] by ! addition ( ! meal1 x is necess>y to /ir ! mass ) r$\bl$ vigor if any?+ is to be reta9$ )9 ! kettle4 ,! ?ick5+ ( ! mu% increases its viscosity to su* an ext5t t ! /eam :i* is g5]at$ )9 x is unable to make its escape unless aid$ by op5+s cont9ually made = x by ! /irr+ spoon4 ,if ! /irr+ motion be /opp$ = a mom5t1 ! /eam exp&s to =m great bubbles :i* soon eject ! pa/y mass f ! kettle4 ,= ! crat] ( ,/romboli ?is process is illu/rat$ by ! s]ies ( diagrams 9 ,fig4 #aab4 ,z ! lava rises t[>d ! surface1 presumably z a result ( convectional curr5ts )9 ! *imney ( ! volcano1 ! conta9$ /eam is reliev$ f pressure1 s t at "s dep? bel[ ! surface x beg9s to sep>ate out 9 m9ute vesicles or bubbles1 :i*1 exp&+ z !y rise1 acquire a rapidly accel]at+ velocity4 ,soon !y fl[ toge!r ) a q sudd5 increase ( _! expansive en]gy1 & n[ %oot+ upw>d ) fur!r accel]at$ velocity1 a lay] ( liquid lava ) its cov] ( scum is rais$ on ! surface ( a gigantic bubble & ?r[n high into ! air4 ,cool$ dur+ _! flight1 ! quickly congeal$ lava masses become ! tuff or volcanic a% :i* is ! mat]ial ( ! c9d] cone4 ,illu/ration3 ,,fig4 #aab4--;,diagrams to illu/rate ! nature ( eruptions )9 ! crat] ( ,/romboli4 ,gr&] volcanic eruptions ( c9d] cones4--,mo/ c9d] & composite cones1 9 ! int]vals betwe5 _! gr&] eruptions1 if n entirely quiesc5t1 lapse into a p]iod1 ( light activity dur+ :i* _! crat] eruptions appe> to be 9 all ess5tial respects l ! habitual explosions )9 ! ,/rombolian crat]4 ,?is phase ( activity is1 !re=e1 describ$ z ,/rombolian4 ,by contra/1 ! occasional gr&] eruptions :i* h punctuat$ ! hi/ory ( all l>g] volcanoes are describ$ 9 ! language ( ,m]calli z ,vulcanian eruptions1 f ! be/ /udi$ example4 ,j :at x is t at int]vals br+s on ! gr&] ,vulcanian outbur/ )9 a volcano is n kn[n ) c]ta9ty2 b x is important to note t !re is an approa* to p]iodicity 9 ! gr&] eruptions4 ,x is g5]ally possible to di/+ui% eruptions ( at lea/ two ord]s ( int5sity great] ?an ! ,/rombolian phase2 a gr&] "o1 ! examples ( :i* may be sep>at$ by c5turies1 & "o or m ord]s ( relatively mod]ate int5sity :i* recur at int]vals p]haps ( decades1 _! "t int]vals subdivid+ ! l>g] p]iods m>k$ (f by ! eruptions ( ! fir/ ord]4 ,illu/ration3 ,,fig4 #aac4--,map ( ,volcano 9 ! ,eolian gr\p ( isl&s4 ,! small] crat]s p>tially dissect$ by ! waves belong to ,vulcanello 7aft] ,judd74 ,! eruption ( ,volcano 9 #ahhh4--;,9 ! ,eolian ,isl&s to ! nor? ( ,sicily 0 locat$ ! my?ical =ge ( ,vulcan4 ,f ?is locality has come our ^w 8volcano01 & bo? ! isl& & ! m\nta9 be> no o!r "n to-day 7,fig4 #aac74 ,!re is 9 ! /ructure ( ! isl& ! record ( a some:at complex volcanic hi/ory1 b ! =m ( ! l>ge c5tral c9d] cone 01 accord+ to ,scrope1 acquir$ dur+ ! eruption ( #aghf1 at :i* "t ! crat] is report$ to h vomit$ a% = a p]iod ( fifte5 days4 ,pass+ aft] ?is eruption into ! solfat>a condition1 ) ! exception ( a light eruption 9 #ahgc1 ! volcano rema9$ quiet until #ahhf4 ,s active _h be5 ! fum]oles )9 ! crat] dur+ ! latt] "p ( ?is p]iod t an ext5sive plant _h be5 e/abli%$ !re = ! collection especially ( boracic acid4 ,9 #ahhf occurr$ a slight eruption1 suffici5t to cle> out ! bottom ( ! crat]1 ?\gh n s]i\sly to di/urb ! ,engli% plant] ^: v9ey>ds & fig or*>ds 7 9 ! valley or atrio ne> ! po9t d ^u ! map 7,fig4 #aac71 ne>ly a mile f ! crat] rim4 ,on ! #c;d ( ,augu/1 #ahhh1 came ! op5+ dis*>ge ( an eruption1 :i*1 :ile n ( ! fir/ ord] ( magnitude1 0 yet ! greate/ 9 m ?an a c5tury ( ! m\nta9's hi/ory1 & may s]ve u to illu/rate ! ,vulcanian phase ( activity )9 a c9d] cone4 ,dur+ ! day1 to ! accompanim5t ( explosions ( consid]able viol5ce1 projectiles fell outside ! crat] rim & roll$ d[n ! /eep slopes t[>d ! atrio4 ,^! explosions 7 repeat$ at int]vals ( f tw5ty to ?irty m9utes1 ea* beg9n+ 9 a great upw>d ru% ( /eam & a%1 accompani$ by a l[ rumbl+ s\nd4 ,dur+ ! foll[+ night ! eruptions increas$ 9 viol5ce1 & ! anxi\s plant] rema9$ on wat* 9 8 villa a mile f ! crat]4 ,fall+ asleep t[>d morn+1 he 0 rudely awak5$ by a ra9 ( projectiles fall+ ^u 8 ro(4 ,ha/ily snat*+ up 8 two *ildr5 he ran t[>d ! door j z a r$ hot projectile1 "s two feet 9 diamet]1 desc5d$ ?r\gh ! ro(1 ceil+1 & floor ( ! draw+ room1 sett+ fire to ! build+4 ,a second projectile simil> to ! fir/ 0 sma%$ into fragm5ts at 8 feet z he 0 em]g+ f ! h\se1 burn+ "o ( ! *ildr54 ,mak+ 8 escape to ,vulcanello at ! extremity ( ! isl&1 ! rema9d] ( ! night & ! foll[+ day1 until rescue came f ,lip>i1 7 sp5t j beyond ! range ( ! fall+ masses4 ,illu/ration3 ,,fig4 #aad4--8;,bread-cru/0 lava projectile f ! eruption ( ,volcano 9 #ahhh 7aft] ,m]calli74 ,:5 ! writ] visit$ ! isl& "s mon?s lat]1 ! eruption 0 /ill s vigor\s t ! crat] c\ld n be rea*$4 ,! ru9$ villa1 sma%$ & *>r$1 /ood ) its walls half buri$ 9 a% & lapilli1 among :i* 7 p>tly sma%$ pumice\s lava projectiles4 ,! entire atrio ab\t ! m\nta9 lay buri$ 9 c9d] to ! dep? ( sev]al feet & 0 /rewn ) projectiles :i* v>i$ 9 size f a man's fi/ to sev]al feet 9 diamet] 7,fig4 #aad74 ,! l>g] ( ^! exhibit$ ! peculi> 8bread-cru/0 surface & _h g5]ally be5 sma%$ by ! =ce ( _! fall aft] ! mann] ( a pumpk9 :i* has be5 ?r[n h>d aga9/ ! gr\nd4 ,"o ( ^! projectiles fully ?ree feet 9 diamet] 0 f\nd at ! di/ance ( a mile & a half f ! crat]4 ,?\gh dim9i%$ consid]ably 9 int5sity1 ! rhy?mic explosions )9 ! crat] /ill recurr$ at int]vals v>y+ f f\r m9utes to half an h\r1 & 7 accompani$ by a dull ro> easily he>d at ,lip>i on a neighbor+ isl& six miles away4 ,simultane\sly1 a d>k cl\d ( 8smoke01 ! peculi> 8caulifl[] cl\d0 or p9o m\nt$ = a c\ple ( miles above ! crat] 7,fig4 #aae71 & ! rise 0 succe$$ by a ra9 ( small lava fragm5ts or lapilli outside ! crat] rim4 ,illu/ration3 ,,fig4 #aae4--,peculi> 8caulifl[] cl\d0 or p9o compos$ ( /eam & a%1 ris+ above ! c9d] cone ( ,volcano dur+ ! wan+ phases ( ! explosive eruption ( #ahhh 7aft] a photograph by ,b4 ,hobson74 ,!re seems to be no good reason to d\bt t ,vulcanian c9d] eruptions ( ?is type diff] *iefly 9 magnitude f ! rhy?mic explosion )9 ! crat] ( ,/romboli1 if we except ! elevation ( a consid]able quantity ( accessory & old] tuff :i* is d]iv$ f ! inn] walls ( ! crat] & c>ri$ upw>d into ! air toge!r ) ! pa/y cakes ( fre% lava d]iv$ f ! *imney4 ,x is ?is accessory mat]ial :i* gives to ! p9o its d>k or ev5 black appe>ance4 ,illu/ration3 ,,fig4 #aaf4--;,d\ble explosive eruption ( ,taal volcano on ! morn+ ( ,janu>y #cj1 #aiaa4 ,! eruption ( ,taal volcano on ,janu>y #cj1 #aiaa4--,! rec5t eruption ( ! c9d] cone kn[n z ,taal volcano is ( int]e/1 n only because s fre% 9 m9d1 b because two neighbor+ v5ts erupt$ simultane\sly ) explosions ( ne>ly equal viol5ce 7,fig4 #aaf74 ,?is ,philipp9e volcano lies ne> ! c5t] ( a lake "s fifte5 miles 9 diamet] & ab\t fifty miles s\? ( ! city ( ,manila4 ,aft] a p]iod ( re/ ext5d+ ov] "o hundr$ & fifty ye>s1 ! symptoms ( ! com+ eruption develop$ rapidly1 & on ! morn+ ( ,janu>y #cj gr& explosions ( /eam & a% occurr$ simultane\sly 9 ! neighbor+ crat]s1 & ! cond5s$ moi/ure br\ght d[n ! a% 9 an avalan*e ( scald+ mud :i* buri$ ! entire isl&4 ,almo/ ! entire population ( ! isl&1 numb]+ sev]al hundr$s1 0 lit]ally buri$ 9 ! bli/]+ mud 7,fig4 #aag72 & ! gases f ! explosions c>ri$ to ! di/ant %ores ( ! lake add$ to ?is numb] _m hundr$ victims4 ,illu/ration3 ,,fig4 #aag4--,! ?ick mud v5e] ^u ! isl& ( ,taal 7aft] a photograph by ,d5i/on74 ,illu/ration3 ,,fig4 #aah4--;,a pe>-%ap$ lava projectile4 ,! %ocks :i* accompani$ ! explosions rais$ a great wave ^u ! surface ( ! lake1 :i*1 advanc+ ^u ! %ores1 wa%$ away /ructures = a di/ance ( ne>ly a half mile4 ,! mat]ials & ! /ructure ( c9d] cones4--,obvi\sly ! mat]ials :i* compose c9d] cones are ! cool$ lava fragm5ts ( v>i\s degrees ( co>s5ess :i* h be5 eject$ f ! crat]4 ,if l>g] ?an a f+] jo9t1 su* fragm5ts are ref]r$ to z volcanic projectiles1 or1 incorrectly1 z 8volcanic bombs40 ,( ! l>g] masses x is (t5 true t ! =ce ( expulsion has n be5 appli$ opposite ! c5t] ( mass ( ! body4 ,?us x foll[s t !y und]go complex :irl+ motions dur+ _! flight1 & be+ /ill semiliquid1 !y develop curi\s pe>-%ap$ or less regul> =ms 7,fig4 #aah74 ,:5 cry/als h already sep>at$ out 9 ! lava be=e its rise 9 ! *imney ( ! volcano1 ! surr\nd+ fluid lava may be bl[n to f9ely divid$ volcanic du/ :i* floats away ^u ! w9d1 ?us leav+ ! cry/als intact to desc5d z a cry/al ra9 ab\t ! crat]4 ,su* a %[] occurr$ 9 connection ) ! eruption ( ,etna 9 #affi1 & ! black augite cry/als may to-day be ga!r$ by ! h&ful f ! slopes ( ! ,monti ,rossi 7,fig4 #abe1 p4 #abe74 ,illu/ration3 ,,fig4 #aai4--;,artificial production ( ! /ructure ( a c9d] cone ) use ( color$ s&s c>ri$ up 9 alt]nation by a curr5t ( air 7aft] ,g4 ,l9ck74 ,! t]m lapilli1 or sometimes rapilli1 is appli$ to ! eject$ lava fragm5ts :5 ( ! av]age size ( a f+] jo9t4 ,?is is ! mat]ial :i* /ill p>tially cov]s ! unexhum$ portions ( ! city ( ,pompeii4 ,volcanic s&1 a%1 & du/ are t]ms appli$ 9 ord] to increas+ly f9e p>ticles ( ! eject$ lava4 ,! f9e/ mat]ial1 ! volcanic du/1 is (t5 c>ri$ = hundr$s & sometimes ev5 = ?\s&s ( miles f ! crat] 9 ! high-level curr5ts ( ! atmosph]e4 ,inasmu* z ?is mat]ial is deposit$ f> f ! crat] & 9 lay]s m or less horizontal1 su* mat]ial plays a small rle 9 ! =mation ( ! c9d] cone4 ,! co>s] s&s & a%1 on ! o!r h&1 are ! mat]ials f :i* ! c9d] cone is l>gely con/ruct$4 ,! mann] ( =mation & ! /ructure ( c9d] cones may be illu/rat$ by use ( a simple laboratory app>atus 7,fig4 #aai74 ,?r\gh an op5+ 9 a bo>d1 fir/ :ite & !n color$ s& is s5t up 9 a light curr5t ( air or gas suppli$ f suitable app>atus4 ,! alt]nat+ lay]s ( ! s& =m 9 ! attitudes %[n2 t is to say1 dipp+ inw>d or t[>d ! *imney ( ! volcano at all po9ts )9 ! crat] rim1 & outw>d or away f x at all po9ts outside 7,fig4 #aai74 ,if ! exp]im5t is c>ri$ s f> t at its t]m9ation s& slides d[n ! crat] walls into ! *imney bel[1 ! inw>d dipp+ lay]s w be truncat$1 or ev5 remov$ entirely1 z %[n 9 ,fig4 #aai b4 ,illu/ration3 ,,fig4 #abj4--;,diagram to %[ ! contra/ betwe5 a lava dome & a c9d] cone4 ,,aaa1 c9d] cone2 ,bab,c1 lava dome2 ,,de1 l9e ( l[ c9d] cones above a fissure 7aft] ,?orodds574 ,! pr(ile l9es ( c9d] cones4--,! %apes ( c9d] cones are notably diff]5t f ^? ( lava m\nta9s4 ,:ile ! latt] are domes1 ! m\nta9s con/ruct$ ( c9d] are conical & h curves ( pr(ile t are concave upw>d in/ead ( convex 7,fig4 #abj74 ,9 ! e>li] /ages ( its gr[? ! c9d] cone has a crat] :i* 9 proportion to ! height ( ! m\nta9 is relatively broad 7,fig4 #ii1 p4 #ajd74 ,illu/ration3 ,,fig4 #aba4--,mayon volcano on ! isl& ( ,luzon1 ,p4,i4 ,a rem>kably p]fect high c9d] cone4 ,speak+ broadly1 ! diamet] ( ! crat] is a measure ( ! viol5ce ( ! explosions )9 ! *imney4 ,a s+le s]ies ( %ort & viol5t explosive eruptions builds a l[ & broad c9d] cone4 ,a long-cont9u$ succession ( mod]ately viol5t explosions1 on ! o!r h&1 builds a high cone ) crat] diamet] small if comp>$ ) ! m\nta9's altitude1 & ! pr(ile af=d$ is a rem>kably beautiful sweep+ curve 7,fig4 #aba74 ,t[>d ! summit ( su* a cone ! loose mat]ials ( :i* x is compos$ are at z /eep an angle z !y c lie1 ! s-call$ angle ( repose ( ! mat]ial2 :]eas l[] d[n ! flatt] slopes h be5 det]m9$ by ! di/ribution ( ! c9d] dur+ its fall f ! air4 ,:5 "o makes ! asc5t ( su* a m\nta91 he enc\nt]s cont9ually /eep] grades1 ) ! mo/ difficult slope j bel[ ! cre/4 ,illu/ration3 ,,fig4 #abb4--;,a s]ies ( brea*$ c9d] cones :]e ! place ( eruption has migrat$ along ! und]ly+ fissure4 ,! ,puys ,noir1 ,solas1 & ,la ,va*e 9 ! ,mont ,dore ,prov9ce ( c5tral ,france 7aft] ,scrope74 ,! composite cone4--,! life hi/ories ( volcanoes are g5]ally s v>i$ t lava domes & ! pure types ( c9d] cones are less common ?an volcanoes 9 :i* p>oxysmal eruptions h alt]nat$ ) explosions1 & :]e1 !re=e1 ! /ructure ( ! m\nta9 repres5ts a composite ( lava & c9d]4 ,su* composite cones possess a skeleton ( solid rock ^u :i* h be5 built up alt]nate slop+ lay]s ( c9d] & lava4 ,9 mo/ respects su* cones /& 9 an int]m$iate position betwe5 lava domes & c9d] cones4 ,illu/ration3 ,,fig4 #abc4--,! bocca or m\? ^u ! inn] cone ( ,m\nt ,vesuvius f :i* fl[$ ! lava /ream ( #ahgb4 ,?is lava /ream appe>s 9 ! =egr\nd ) its *>act]i/ic 8ropy0 surface4 ,reg>d$ z a reta9+ wall = ! lava :i* m\nts 9 ! *imney1 ! c9d] cone is obvi\sly ! weake/ ( all4 ,%\ld lava rise 9 a c9d] cone )\t an explosion occurr+1 ! cone is at once brok5 ?r\gh ^u "o side by ! outwell+ ( ! lava ne> ! base4 ,?us arises ! *>act]i/ic brea*$ cone ( horse%oe =m 7,fig4 #abb74 ,illu/ration3 ,,fig4 #abd4--;,a r[ ( p>asitic cones rais$ above a fissure :i* 0 op5$ ^u ! flanks ( ,m\nt ,etna dur+ ! eruption ( #ahib 7aft] ,de ,lor5zo74 ,q 9 contra/ ) ! weak c9d] cone is ! lava dome ) its rock walls & relatively flat slopes4 ,consid]$ z a reta9+ wall = lava x is mu* ! /ronge/ type ( volcanic m\nta91 & x is likely t ! hydro/atic pressure ( ! lava )9 ! crat] w\ld seldom suffice to rupture ! walls1 7 x n t ! molt5 rock fir/ fuses its way into old /ream tunnels buri$ "u ! m\nta9 slopes 7see ante1 p4 #aab74 ,composite cones h a /r5g? z reta9+ walls = lava :i* is int]m$iate betwe5 t ( ! o!r types4 ,_! ,vulcanian eruptions ( ! convulsive type are initiat$ by ! =mation ( a r5t or fissure ^u ! m\nta9 flanks at elevations well above ! base1 ! op5+ ( ! fissure be+ g5]ally accompani$ by a local e>?quake ( great] or less viol5ce4 ,f "o or m su* fissures ! lava issues usually ) suffici5t viol5ce at ! place ( outfl[ to build up ov] x ei!r an enl>g$ type ( driblet cone1 ref]r$ to z a 8m\?01 or bocca#a 7,fig4 #abc71 or "o or m c9d] cones :i* f _! position ^u ! flanks ( ! l>g] volcano are ref]r$ to z p>asitic cones 7,fig4 #abd74 ,! lava ( ,vesuvius m frequ5tly yields boc*i at ! place ( outfl[1 :]eas ! flanks ( ,etna are pimpl$ ) great numb]s ( p>asitic c9d] cones1 ea* ! monum5t to "s e>li] eruption 7,fig4 #abe74 ,illu/ration3 ,,fig4 #abe4--,view look+ t[>d ! summit ( ,etna f a position ^u ! s\!rn flank ne> ! village ( ,nicolosi4 ,! two brea*$ p>asitic cones se5 beh9d ?is village are ! ,monti ,rossi :i* 7 ?r[n up 9 #affi & f :i* fl[$ ! lava :i* ov]ran ,catania 7aft] a photograph by ,somm]74 ,x is g5]ally ! case t a s+le eruption makes b a relatively small contribution to ! bulk ( ! m\nta94 ,f ea* new cone or bocca !re proce$s a /ream ( lava spread 9 a relatively n>r[ /ream ext5d+ d[n ! slopes 7,fig4 #abf74 ,illu/ration3 ,,fig4 #abf4--,sket* map ( ,etna1 %[+ ! individual surface lava /reams 79 black7 & ! tuff cov]$ surface 7/ippl$74 ,! cald]a ( composite cones4--,because ( ! v>i$ episodes 9 ! hi/ory ( composite cones1 !y lack ! regul> l9es *>act]i/ic ( ! two simpl] types4 ,! l>g] numb] ( ! m important composite cones h be5 built up )9 an out] crat] ( relatively l>ge diamet]1 ! ,somma cone or cald]a1 :i* surr\nds !m l a gigantic ruff or coll>4 ,?is cald]a is cle>ly 9 mo/ cases at lea/ ! relic ( an e>li] explosive crat]1 aft] :i* successive eruptions ( less] viol5ce h built a m %>ply conical /ructure4 ,?is c only be int]pret$ to mean t mo/ l>g] & long-active volcanoes h be5 born 9 ! gr&e/ ?roes ( _! life hi/ory1 & t a l>g] or small] lat]al migration ( ! v5t has be5 responsible = ! p>tial de/ruction ( ! explosion crat]4 ,^u ,vesuvius we f9d ! cresc5t-l rim ( ,monte ,somma2 on ,etna x is ! ,val del ,bove1 etc4 ,x is ?is cald]a ( composite cones :i* gave rise to ! !ory ( ! 8elevation crat]0 ( von ,bu* 7see ante1 p4 #ie1 & ,fig4 #abg74 ,illu/ration3 ,,fig4 #abg4--,panum crat]1 %[+ ! cald]a & ! lat] int]ior cones 7aft] ,russell74 ,! eruption ( ,vesuvius 9 #aijf4--,! volcano ,vesuvius rises on ! %ores ( ! beautiful bay ( ,naples only ab\t t5 miles di/ant f ! city ( ,naples4 ,! m\nta9 consi/s ( ! remnant ( an e>li] broad-m\!d explosion crat]1 ! ,monte ,somma1 & an inn]1 m conical elevation1 ! ,monte ,vesuvio4 ,be=e ! eruption ( #aijf ?is c5tral cone 0 %>ply conical & rose to a height ( ab\t #dcjj feet above ! surface ( ! bay1 or above ! highe/ po9t ( ! anci5t cald]a4 ,! base ( ?is inn] cone is at an elevation ( some?+ less ?an half t ( ! entire mass1 & is sep>at$ f ! encircl+ r+ wall ( ! old crat] by ! atrio1 to :i* corresponds 9 height a p]ceptible %elf or piano ^u ! slope t[>d ! bay ( ,naples 7,fig4 #abh74 ,illu/ration3 ,,fig4 #abh4--,view ( ,m\nt ,vesuvius z x appe>$ f ! ,bay ( ,naples %ortly be=e ! eruption ( #aijf4 ,! horn to ! left is ,monte ,somma4 ,an active composite cone l t ( ,vesuvius is = ! great] "p ( ! "t 9 ! ,/rombolian condition2 t is to say1 light crat] explosions cont9ue ) v>y+ int5sity & int]val1 except :5 ! m\nta9 has be5 excit$ to ! p]iodic ,vulcanian outbreaks ) :i* its hi/ory has be5 punctuat$4 ,! ,/rombolian explosions h suffici5t viol5ce to eject small fragm5ts ( hot lava1 :i*1 fall+ ab\t ! crat]1 sl[ly built up a r %>p cone4 ,! p]iod ( ,/rombolian activity has1 !re=e1 be5 call$ ! cone-produc+ p]iod4 ,j be=e ea* new outbreak ( ! ,vulcanian type1 ! altitude ( ! m\nta9 has1 !re=e1 rea*$ a maximum1 & s9ce ! l>g] explosive eruptions remove portions ( ?is cone at ! same "t t !y increase ! dim5sions ( ! crat]1 ! ,vulcanian /age 9 contra/ to ! o!r has be5 call$ ! crat]-produc+ p]iod4 ,9 ?is p]iod1 !n1 ! mat]ial eject$ dur+ ! explosions does n consi/ solely ( fre% lava cakes1 b 9 "p ( ! old] dbris d]iv$ f ! crat] walls1 :5ce x is avalan*$ ^u ! *imney aft] ea* l>g] explosion4 ,! ov]hang+ cl\d1 :i* dur+ ! ,/rombolian p]iod has consi/$ l>gely ( /eam & is noticeably :ite1 n[ assumes a d>k] tone1 ! 8smoke0 :i* *>act]izes ! ,vulcanian eruption4 ,illu/ration3 ,,fig4 #abi4--;,a s]ies ( consecutive sket*es ( ! summit ( ! ,vesuvian cone1 %[+ ! modifications 9 its outl9e 7aft] ,sir ,william ,hamilton74 ,on sev]al hi/orical occasions ! cone ( ,vesuvius has be5 l[]$ by sev]al hundr$ feet1 ! greate/ ( relatively rec5t truncations hav+ occurr$ 9 #ahbb & 9 #aijf4 ,betwe5 ,vulcanian eruptions ! ,/rombolian activity is by no means uni=m1 & s ! upw>d gr[? ( ! cone is subject to less] int]ruptions & truncations 7,fig4 #abi74 ,! ,vesuvian eruption ( #aijf has be5 select$ z a type ( ! l>g] ,vulcanian eruption ( composite cones1 because x comb9$ ! explosive & p>oxysmal elem5ts1 & because x has be5 obs]v$ & /udi$ ) great] ?or\ghness ?an any o!r4 ,! late/ previ\s eruption ( ! ,vulcanian ord] _h occurr$ 9 #ahgb4 ,"s two ye>s lat] ! p]iod ( active cone build+ began & proce$$ ) su* rapidity t by #ahhj ! new cone began to appe> above ! rim ( ! crat] ( #ahgb4 ,f ?is "t on occasional light eruptions int]rupt$ ! upbuild+ process1 & z ! repairs 7 n 9 all cases complet$ be=e a new int]ruption1 a ne/ ( cones1 ea* small] ?an ! la/1 arose 9 s]ies l ! outdrawn sections ( an old-"t spyglass4 ,at "o "t no less ?an five conc5tric crat]s 7 to be se54 ,= a brief p]iod 9 ! fall ( #aijd ,vesuvius _h be5 9 almo/ absolute repose1 b soon !reaft] ! ,/rombolian crat] explosions 7 resum$4 ,on ,may #be1 #aije1 a small /ream ( lava began to issue f a fissure high up ^u ! c5tral cone1 & f ?is "t on ! lava cont9u$ to fl[ d[n to ! valley or atrio1 sep>at+ ! inn] cone f ! cald]a remnant ( ,monte ,somma4 ,se5 9 ! night1 ?is /ream ( lava appe>$ f ,naples l a r$ hot wire laid aga9/ ! m\nta9's side 7,fig4 #acj74 ,) gradual augm5tation ( ,/rombolian explosions & increase 9 volume ( ! fl[+ lava /ream1 ! same condition cont9u$ until ! fir/ days ( ,april 9 #aijf4 ,! fl[+ lava _h !n ov]run ! tracks ( ! m\nta9 railway & accumulat$ 9 consid]able quantity )9 ! atrio 7,fig4 #aca74 ,illu/ration3 ,,fig4 #acj4--,night view ( ,vesuvius f ,naples be=e ! outbreak ( #aijf4 ,a small lava /ream is se5 desc5d+ f a high po9t ^u ! c5tral cone 7aft] ,m]calli74 ,on ! morn+ ( ,april #d1 a prelim9>y /age ( ! eruption 0 inaugurat$ by ! op5+ ( a new radial fissure ab\t #ejj feet bel[ ! summit ( ! cone 7,fig4 #acb a71 & by e>ly aft]noon ! cone-de/roy+ /age began ) ! rise ( a d>k 8caulifl[] cl\d0 or p9o to replace ! light] color$ /eam cl\d4 ,! cone 0 beg9n+ to fall into ! crat]1 & old lava dbris 0 m+l$ 9 ! ejections ) ! lava clots bl[n f ! /ill fluid mat]ial )9 ! *imney4 ,f n[ on %ort & snappy lightn+ fla%es play$ ab\t ! black cl\d1 giv+ out a %>p /accato 8tack-a-tack40 ,! volume & d5sity ( ! cl\d & ! int5sity ( ! crat] explosions cont9u$ to increase until ! culm9ation on ,april #g4 ,on ,april #e at midnight a new lava m\? appe>$ ^u ! same fissure :i* _h op5$ ne> ! summit1 b n[ "s #cjj feet l[] 7,fig4 #acb b74 ,! lava n[ well$ out 9 l>g] volume correspond+ to its great] head1 & ! /ream :i* = t5 mon?s _h be5 fl[+ f ! highe/ outlet ^u ! cone n[ ceas$ to fl[4 ,! next morn+1 ,april #f1 at ab\t #h o'clock1 lava broke out at sev]al po9ts "s di/ance ea/ ( ! op5+ b1 & evid5tly ^u ano!r fissure transv]se to ! fir/ 7,fig4 #acb c74 ,! lava surface )9 ! *imney mu/ /ill h rema9$ ne> its old level1--effective dra9+ _h n yet begun1--s9ce e>ly ^u ! foll[+ morn+ a small outfl[ began ne>ly at ! top ( ! cone ^u ! opposite side & at lea/ a ?\s& feet high]4 ,illu/ration3 ,,fig4 #aca4--,scoriace\s lava encroa*+ ^u ! tracks ( ! ,vesuvian railway 7aft] a photograph by ,somm]74 ,illu/ration3 ,,fig4 #acb4--,map ( ,vesuvius1 %[+ ! position & ord] ( =mation ( ! lava m\?s ^u its flanks dur+ ! eruption ( #aijf 7aft] ,john/on-,lavis74 ,! culm9ation ( ! eruption came 9 ! ev5+ ( ,april #g1 :51 to ! accompanim5t ( light e>?quakes felt z f> z ,naples1 lava issu$ = ! fir/ "t 9 great volume f a m\? m ?an halfway d[n ! m\nta9 side 7,fig4 #acb f71 & ?us began ! dra9age ( ! *imney4 ,at ab\t ! same "t ) l\d detonations a huge black cl\d rose above ! crat] 9 connection ) heavy explosions1 & a ra9 ( c9d] 0 g5]al 9 ! region ab\t ! m\nta9 b especially )9 ! nor!a/ quadrant4 ,^? :o 7 s =tunate z to be 9 ,pompeii _h a cle> view ( ! m\nta9's summit :]e r$ hot masses ( lava 7 ?r[n f> into ! air4 ,! direction ( ^! projections 0 report$ to h be5 n directly upw>d1 b incl9$ t[>d ! nor!a/ quadrant ( ! m\nta92 b s9ce ) a nor!a/ surface w9d ! heavie/ deposit ( a% & du/ %\ld h be5 ^u ! s\?we/]n quadrant ( ! m\nta91 x is evid5t t ! mat]ial 0 c>ri$ upw>d until x rea*$ ! contr>y upp] curr5ts ( ! atmosph]e1 to be by !m di/ribut$4 ,illu/ration3 ,,fig4 #acc4--,! a% curta9 :i* _h ov]hung ,vesuvius lift+ & disclos+ ! outl9es ( ! m\nta9 on ,april #aj1 #aiaa 7aft] ,de ,lor5zo74 ,illu/ration3 ,,fig4 #acd4--,! c5tral cone ( ,vesuvius z x appe>$ aft] ! eruption ( #aijf1 b ) ! e>li] pr(ile indicat$4 ,! truncation repres5ts a l[]+ ( ! summit by "s five hundr$ feet1 ) correspond+ increase 9 ! diamet] ( ! crat] 7aft] ,john/on-,lavis74 ,:5 ! heavy curta9 ( a%1 :i* n[ = a numb] ( succe$+ days ov]hung all ! circum-,vesuvian c\ntry1 began to lift 7,fig4 #acc71 x 0 se5 t ! summit ( ! cone _h be5 truncat$ an av]age ( "s #ejj feet 7,fig4 #acd74 ,all ! slopes & mu* ( ! surr\nd+ c\ntry _h ! aspect ( be+ buri$ b5ea? a cocoa-color$ sn[ ( a dep? to ! nor!a/w>d ( sev]al feet1 :]e x _h drift$ into all ! holl[ ways s z almo/ to efface !m 7,fig4 #ace74 ,m ?an ?rice z heavy z wat]1 ! weak ro( timb]s ( ! h\ses at ! base ( ! m\nta9 gave way b5ea? ! add$ load ^u !m1 ?us mak+ _m victims4 ,inasmu*1 h[ev]1 z ! a%-fall p>takes ( ! same g5]al *>act]s z 9 eruptions f c9d] cones1 we may "h give our att5tion especially to ! /reams ( lava :i* issu$ ^u ! opposite flank ( ! m\nta9 7,fig4 #acf74 ,illu/ration3 ,,fig4 #ace4--;,a sunk5 road fill$ ) indrift$ cocoa-color$ a% f ! ,vesuvian eruption ( #aijf4 ,illu/ration3 ,,fig4 #acf4--,view ( ,vesuvius tak5 f ! s\?we/ dur+ ! wan+ /ages ( ! eruption ( #aijf4 ,9 ! middle di/ance may be disc]n$ ! sev]al lava m\?s align$ ^u a fissure1 & ! c\rses ( ! /reams :i* desc5d f !m4 ,9 ! =egr\nd is ! ma9 lava /ream ) scoriace\s surface 7aft] ,w4 ,pr9z74 ,! ma9 lava /ream desc5d$ ! fir/ /eep slopes ) ! velocity ( a mile 9 tw5ty-five m9utes1 ab\t ! /roll+ spe$ ( a p$e/rian1 b ?is rate 0 gradually r$uc$ z ! /ream advanc$ f>!r f ! m\?4 ,tak+ advantage ( ea* depression ( ! surface1 ! black /ream advanc$ sl[ly b rel5tlessly t[>d ! cities at ! s\?we/ base ( ! m\nta94 ,) a motion n unlike t ( a heap ( coal fall+ ov] itself d[n a slope1 ! block lava advances )\t burn+ ! objects 9 its pa? 7,fig4 #acg74 ,illu/ration3 ,,fig4 #acg4--,! ma9 lava /ream ( #aijf advanc+ ^u ! village ( ,boscotrecase4 ,illu/ration3 ,,fig4 #ach4--;,an ,italian p9e snapp$ (f by ! lava & c>ri$ =w>d ^u its surface z a pass5g] 7aft] ,haug74 ,! beautiful p9es are m]ely *>r$ :]e snapp$ (f & are c>ri$ =w>d ^u ! surface ( ! /ream 7,fig4 #ach74 ,:5 a real ob/ruction1 su* z a bridge or a villa1 is enc\nt]$1 ! /ream is at fir/ halt$1 b ! re> cr[d+ ^u ! van1 unless a passage is f\nd at ! side1 ! lava front rises high] & high] until by its weight ! ob/ruction is =c$ to give way 7,figs4 #aci & #adj74 ,illu/ration3 ,,fig4 #aci4--,lava front bo? pu%+ ov] & runn+ ar\nd a wall :i* lies a?w>t its c\rse 7aft] ,john/on-,lavis74 ,illu/ration3 ,,fig4 #adj4--,"o ( ! villas 9 ,boscotrecase :i* 0 ru9$ by ! ,vesuvian lava fl[ ( #aijf4 ,! fragm5ts ( masonry f ! ru9$ walls travel$ ^u ! lava curr5t1 :]e !y sometimes became incas$ 9 lava4 ,! sequ5ce ( ev5ts )9 ! *imney4--,! ?or\gh /udy ( ?is ,vesuvian eruption has plac$ u 9 a position to inf] ) "s confid5ce 9 our conclusions ! sequ5ce ( ev5ts )9 ! *imney & crat] ( ! volcano1 bo? be=e & dur+ ! eruption4 ,anticipat+ "s conclusions d]iv$ f ! obs]v$ dissection ( volcanoes1 :i* w be discuss$ bel[1 x may be /at$ t :at might be t]m$ ! core ( ! composite cone--! *imney--is a m or less cyl9drical plug ( cool$ lava :i* dur+ ! active p]iod ( ! v5t has an int]ior bore ( probably v>iable calib]4 ,?is plug 9 its l[] section appe>s 9 solid black 9 all ! diagrams ( ,fig4 #ada4 ,dur+ ! cone-build+ p]iod 7,fig4 #ada a & b7 ! plug is obvi\sly built upw>d along ) ! cone1 = lava (t5 fl[s out at a level a few hundr$ feet only bel[ ! crat] rim4 ,by :at process ?is *imney build+ goes on is n well und]/ood1 ?\gh "s light is ?r[n ^u x by ! po/-eruption /age ( ,mont ,pel 9 #aijb-aijc 7see bel[74 ,illu/ration3 ,,fig4 #ada4--,?ree diagrams to illu/rate ! sequ5ce ( ev5ts )9 ! crat] ( a composite cone dur+ ! cone-build+ & crat]-produc+ p]iods4 a & b1 two successive /ages ( ! cone build+ or ,/rombolian p]iod2 c1 enl>gem5t ( ! crat]1 truncation ( ! cone1 & de/ruction ( ! upp] *imney dur+ ! relatively brief crat]-produc+ or ,vulcanian p]iod4 ,bo? ! old] & new] sections ( ?is plug or *imney are furni%$ "s support aga9/ ! outw>d pressure ( ! conta9$ lava by ! surr\nd+ wall ( tuff2 & !y are1 !re=e1 9 a condition n unlike t ( ! inn] b>rel ( a great gun ov] :i* sleeves ( metal h be5 %runk s z to give support aga9/ bur/+ pressures4 ,on ! o!r h&1 :5 n su/a9+ ! hydro/atic pressure ( ! liquid lava )91 ! *imney w\ld t5d to be cru%$ 9 by ! pressure ( ! surr\nd+ tuff4 ,its /r5g? to )/& bur/+ pressures is dep5d5t n alone ^u ! ?ickness ( its rock walls1 b also ^u its int]nal diamet] or calib]4 ,a /eam cyl9d] ( giv5 ?ickness ( wall1 z is well kn[n1 c resi/ bur/+ pressures 9 proportion z its int]nal diamet] is small4 ,s 9 ! volcanic *imney1 any t5d5cy to remelt f )9 ! *imney walls mu/ weak5 !m 9 a tw(old ratio4 ,we are yet )\t accurate temp]ature obs]vations ^u ! lava 9 volcanic *imneys1 b x seems almo/ c]ta9 t ^! temp]atures rise z ! ,vulcanian /age is approa*+1 & su* elevation ( temp]ature mu/ be foll[$ by a great] or less re-fusion ( ! *imney walls4 ,! sequ5ce ( ev5ts dur+ ! late ,vesuvian eruption is1 !n1 naturally expla9$ by progressive re-fusion & consequ5t weak5+ ( ! *imney walls1 ?us p]mitt+ a radial fissure to op5 ne> ! top & gradually ext5d d[nw>ds4 ,?us at fir/ small & high outlets 7 op5$ insuffici5t to dra9 ! *imney1 b lat]1 on ,april #g1 aft] ?is fissure _h be5 mu* ext5d$ & a new & l>g] "o _h op5$ at a l[] level1 ! dra9+ began & ! surface ( lava comm5c$ rapidly to s9k4 ,illu/ration3 ,,fig4 #adb4--,! sp9e ( ,pel ris+ above ! *imney ( ! volcano aft] ! eruption ( #aijb 7aft] ,hovey74 ,:5 ! rapid s9k+ ( ! lava surface occurr$1 ! l[] lava lay]s 7 almo/ imm$iately reliev$ ( pressure1 ?us caus+ a sudd5 expansion ( ! conta9$ /eam & result+ 9 gr& crat] explosions4 ,! p>tially refus$ & fissur$ upp] *imney1 n[ unable to )/& ! inw>d pressure ( ! surr\nd+ tuff walls1 s9ce outw>d pressures no long] exi/$1 cru%$ 9 & contribut$ its mat]ials & ^? ( ! surr\nd+ tuff to ! fragm5ts ( fre% lava ris+ 9 volume 9 ! gr& explosions 7,fig4 #ada c74 ,9 outl9e1 !n1 ^! seem to be ! conditions :i* are indicat$ by ! sequ5ce ( obs]v$ ev5ts 9 connection ) ! late ,vesuvian outbreak4 ,illu/ration3 ,,fig4 #adc4--,outl9es ( ! ,pel sp9e ^u successive dates4 ,! full l9e repres5ts its outl9e on ,decemb] #bf1 #aijb2 ! dott$-da%$ l9e is a pr(ile ( ,janu>y #c1 #aijb2 :ile ! dott$ l9e is t ( ,janu>y #i1 #aijc4 ,! d>k l9e is a fissure 7aft] ,e4 ,o4 ,hovey74 ,! sp9e ( ,pel4--,! disa/r\s eruption ( ,mont ,pel ^u ,m>t9ique 9 ! ye> #aijb is ( importance 9 connection ) ! int]e/+ problem ( ! upw>d gr[? ( volcanic *imneys dur+ ! cone-build+ p]iod ( a volcano4 ,aft] ! conclusion ( ?is great ,vulcanian eruption1 a sp9e ( lava grew upw>d f ! *imney ( ! ma9 crat] until x _h rea*$ an elevation ( m !n a ?\s& feet above its base1 a figure ( ! same ord] ( magnitude z ! probable height ( ! upp] section ( ! ,vesuvian *imney previ\s to ! eruption ( #aijf4 ,! ,pel sp9e 7,fig4 #adb7 did n gr[ at a uni=m rate1 b 0 subject to small] or l>g] truncations1 b = a p]iod ( #ah days ! upw>d gr[? 0 at ! rate ( ab\t #da feet p] day4 ,lat]1 ! mass split ^u a v]tical plane reveal+ a concave inn] surface1 & 0 some:at rapidly r$uc$ 9 altitude to #fjj feet 7,fig4 #adc71 only to rise aga9 to its full height ( ab\t #ajjj feet "s ?ree mon?s lat]4 ,:ile app>5tly unique z an obs]v$ ph5om5on1 & n free f unc]ta9ty z to its int]pretation1 ! gr[? ( ?is obelisk has at lea/ %[n u t a mass ( rock c pu% its way up above ! *imney ( an active volcano ev5 :5 !re are no walls ( tuff ab\t x to su/a9 its outw>d pressures4 ,illu/ration3 ,,fig4 #add4--;,corrugat$ surface ( ! ,vesuvian cone aft] ! mud fl[s :i* foll[$ ! eruption 9 #aijf 7aft] ,john/on-,lavis74 ,! aft]ma? ( mud fl[s4--,:5 ! late ,vulcanian explosions ( ,vesuvius _h come to an end1 all slopes ( ! m\nta91 b especially ! high] ones1 7 buri$ 9 ?ick deposits ( ! cocoa-color$ a%1 includ$ 9 :i* 7 l>g] & small] projectiles4 ,z ?is mat]ial is extremely por\s1 x gre$ily sucks up ! wat] :i* falls dur+ ! fir/ succe$+ ra9s4 ,:5 ne>ly saturat$1 x beg9s to desc5d ! slopes ( ! m\nta9 & soon develops a velocity q 9 contra/ ) t ( ! sl[-mov+ lava4 ,! upp] slopes are ?us d5ud$1 :ile ! fields & ev5 ! h\ses ab\t ! base are invad$ by ^! torr5ts ( mud 7lava d'acqua74 ,inasmu* z ^! mud fl[s are ! inevitable aft]ma? ( all gr&] explosive eruptions1 ! ,italian gov]nm5t has ( late sp5t l>ge sums ( money 9 ! con/ruction ( dikes int5d$ to arre/ _! progress 9 ! future4 ,x 0 /reams ( ?is sort t buri$ ! city ( ,h]culaneum aft] ! explosive eruption ( #gi ,a4,d4 ,aft] ! mud fl[s h occurr$1 ! ,vesuvian cone1 l all simil> volcanic cones "u ! same conditions1 is f\nd ) deep radial corrugations 7,fig4 #add71 su* z 7 long ago describ$ z 8b>rancoes0 & suppos$ to support ! 8elevation crat]0 !ory ( volcano =mation4 ,! dissection ( volcanoes4--,to ! un9itiat$ x might appe> a hopeless und]tak+ to attempt to le>n by obs]vation ! int]nal /ructure ( a volcano1 & especially ( a complex volcano ( ! composite type4 ,! e>lie/ successful attempt appe>s to h be5 made by ,c\nt ,casp> von ,/]nb]g 9 ord] to prove ! correctness ( ! !ory ( 8 fri5d1 ! poet ,goe!4 ,goe! _h claim$ t a little hill 9 ! vic9ity ( ,eg]1 on ! bord]s ( ,bohemia1 0 an ext9ct volcano1 ?\gh ! =emo/ geologi/ ( ! "t ! fam\s ,w]n]1 _h promulgat$ ! doctr9e t ?is hill1 9 common ) o!rs ( simil> aspect1 orig9at$ 9 ! combu/ion ( a b$ ( coal4 ,! elevation 9 "q1 :i* is kn[n z ! ,kamm]bhl1 consi/s ma9ly ( c9d]1 & ,goe! _h ma9ta9$ t if a tunnel 7 to be driv5 horizontally into ! m\nta9 f "o ( its slopes1 a core or plug ( lava w\ld be enc\nt]$ b5ea? ! summit4 ,! excavations1 :i* 7 complet$ 9 #ahcg1 fully v]ifi$ ! poet's view1 = a lava plug 0 f\nd to occupy ! c5t] ( ! mass & to connect ) a small lava /ream ^u ! side ( ! hill 7,fig4 #ade74 ,illu/ration3 ,,fig4 #ade4--,! ,kamm]bhl ne> ,eg]1 %[+ ! tunnel complet$ 9 #ahcg :i* prov$ ! volcanic nature ( ! m\nta9 7aft] ,judd74 ,x is n1 h[ev]1 to su* exp5sive projects t ref]5ce is "h made1 b r to processes :i* are cont9ually go+ on 9 nature1 & on a f> gr&] scale4 ,! mo/ important dissect+ ag5t = our purpose is runn+ wat]1 :i* is cont9ually p>+ d[n ! e>?'s surface & disclos+ its buri$ /ructures4 ,h[ mu* m conv9c+ ?an any results ( artificial excavation1 z evid5ce ( ! int]nal /ructure ( a volcano1 is ! monum5t repres5t$ 9 ,fig4 #adf1 s9ce "h ! lava plug /&s 9 relief l a gigantic ?umb /ill surr\nd$ by a remnant ( c9d] deposits4 ,su* expos$ *imneys ( =m] volcanoes are f\nd 9 _m regions1 & h become kn[n z volcanic necks1 pipes1 or plugs4 ,illu/ration3 ,,fig4 #adf4--,volcanic plug expos$ by natural dissection ( a volcanic cone 9 ,colorado 7,u4 ,s4 ,g4 ,s474 ,illu/ration3 ,,fig4 #adg4--;,a dike cutt+ b$s ( tuff 9 a p>tly dissect$ volcano ( s\?we/]n ,colorado 7aft] ,h[e1 ,u4 ,s4 ,g4 ,s474 ,n infrequ5tly ! b$s ( tuff compos+ ! flanks ( ! volcano1 ^u dissection by ! same process1 br+ to light walls ( cool$ lava /&+ 9 relief 7,fig4 #adg7--! fill+ ( ! fissure :i* gave outlet to ! flanks ( ! m\nta9 at ! "t ( ! eruption4 ,/udy ( expos$ dikes =m$ 9 connection ) rec5t eruptions ( ,vesuvius has %[n t 9 _m in/ances !y are /ill holl[1 ! lava hav+ dra9$ f !m be=e complete consolidation4 ,ano!r ag5t :i* is effective 9 uncov]+ ! buri$ /ructures ( volcanoes is ! action ( waves on %ores4 ,always a relatively vigor\s erosive ag5cy1 ! s(t] /ructures ( volcanic cones are remov$ ) especial facility by ?is ag5t4 ,on ! %ores ( ! isl& ( ,volcano1 ! little cone ( ,vulcanello has be5 ne>ly half c>ri$ away by ! waves1 s z to reveal ) especial p]fection ! /ructure ( ! c9d] b$s z well z ! int]nal rock skeleton ( ! mass4 ,"h ! *>act]i/ic dips ( lava /reams1 int]calat$ z !y n[ are betwe5 tuff deposits & ! lava :i* consolidat$ 9 fissures1 are bo? reveal$4 ,illu/ration3 ,,fig4 #adh4--,map & g5]al view ( ,/4 ,paul's ,rocks1 a volcanic cone dissect$ by waves4 ,9 mid-,atlantic a q p]fect crat]1 ! ,/4 ,paul's ,rocks1 has be5 cut ne>ly 9 half s z to produce a natural h>bor 7,fig4 #adh74 ,9 /ill o!r in/ances we may ?ank ! volcano itself = op5+ up ! int]ior ( ! m\nta9 = our inspection4 ,! eruption 9 #ahhh ( ! ,japanese volcano ( ,b&ai-san1 by remov+ a consid]able "p ( ! anci5t cone1 has af=d$ u a section completely ?r\gh ! m\nta94 ,! summit & "o side ( ! small ,b&ai 0 c>ri$ completely away1 & !re 0 sub/itut$ a yawn+ crat] ecc5tric to ! =m] m\nta9 & hav+ its highe/ wall no less ?an #aejj feet 9 height 7,fig4 #adi74 ,9 two h\rs f ! fir/ w>n+ ( ! explosion ! cata/rophe 0 complete & ! eruption ov]4 ,illu/ration3 ,,fig4 #adi4--;,dissection by explosion ( ,little ,b&ai-san 9 #ahhh 7aft] ,sekiya74 ,! eruption ( ,krakatoa 9 #ahhc1 probably ! gr&e/ obs]v$ volcanic explosion 9 hi/oric times1 left a volcanic cone divid$ almo/ 9 half & op5 to inspection 7,fig4 #aej74 ,rakata1 ,danan1 & ,p]buatan _h be=e con/itut$ a l9e ( cones built up r\nd individual crat]s subsequ5t to ! p>tial de/ruction ( an e>li] cald]a1 portions ( :i* 7 /ill exi/5t 9 ! isl&s ,v]lat5 & ,lang4 ,by ! eruption ( #ahhc all ! expos$ p>ts & consid]able subm]g$ portions ( ! two small] cones 7 entirely de/roy$1 & ! l>g] "o1 kn[n z ,rakata1 0 divid$ j outside ! plug s z to leave a precipit\s wall ris+ directly f ! sea & %[+ lava /reams 9 alt]nation ) some:at ?ick] tuff lay]s1 ! :ole knit toge!r by num]\s lava dikes4 ,illu/ration3 ,,fig4 #aej4--,! half-subm]g$ volcano ( ,krakatoa 9 ! ,sunda ,/raits be=e & aft] ! eruption ( #ahhc 7aft] ,v]beek74 ,9 ord] to c>ry our dissect+ process d[n to levels bel[ ! base ( ! volcanic m\nta91 x is usually necess>y to inspect ! results ( erosion by runn+ wat]4 ,"h ! plug or *imney1 in/ead ( be+ surr\nd$ by tuff1 is inclos$ by ! c\ntry rock ( ! region1 :i* is commonly a s$im5t>y =mation4 ,su* expos$ l[] sections ( volcanic *imneys are num]\s along ! nor?we/]n %ores ( ! ,briti% ,isles4 ,:]e align$ ^u a dislocation or notewor?y fissure 9 ! rocks1 ! gr\p ( plugs has be5 ref]r$ to z a sc> or cicatrice 7,fig4 #aea74 ,associat$ ) ! plugs ( ! cicatrice are n infrequ5tly dikes1 or1 x may be1 %eets ( lava ext5d$ betwe5 lay]s ( s$im5t & kn[n z sills4 ,illu/ration3 ,,fig4 #aea4--,! cicatrice ( ! ,banat 7aft] ,suess74 ,if we are able to cont9ue ! dissection process to /ill great] dep?s1 we enc\nt] at la/ igne\s rock hav+ a texture kn[n z granitic & indicat+ t ! process ( consolidation 0 n only exce$+ly sl[ b also un9t]rupt$4 ,?is rock is f\nd 9 masses ( l>g] dim5sions1 & ?\gh g5]ally ( m or less irregul> =m1 no "o dim5sion is ( a diff]5t ord] ( magnitude f ! o!rs4 ,su* masses are commonly describ$ z bosses1 or1 if especially l>ge1 z ba?olites 7,fig4 #aeb74 ,:]ev] ! rock b$s appe> z ?\gh !y _h be5 =c$ up by ! upw>d pressure ( ! igne\s mass1 ! latt] takes ! =m ( a mu%room & has be5 describ$ z a laccolite 7,figs4 #dgi-dha1 pp4 #dda-ddb74 ,evid5ce seems1 h[ev]1 to accumulate t 9 ! great] numb] ( cases ! molt5 rock has fus$ its way upw>d1 9 "p assimilat+ & 9 "p inclos+ ! rock :i* x enc\nt]$4 ,?is process ( upw>d fusion has be5 lik5$ to ! progress ( a r$ hot iron burn+ its way ?r\gh a bo>d4 ,! =mation ( lava res]voirs4--,! disc>d+ ( ! e>li] notion t ! e>? has a liquid int]ior makes x prop] 9 discuss+ ! subject ( volcanoes to at lea/ t\* ^u ! orig9 ( ! molt5 rock mat]ial4 ,z already po9t$ out1 su* res]voirs z exi/ mu/ be local & tempor>y1 or x w\ld be difficult to see h[ ! exi/+ condition ( e>? rigidity c\ld be ma9ta9$4 ,f ! rate at :i* rock temp]atures rise1 at increas+ dep?s bel[ ! surface1 x is cle> t all rocks w\ld be melt$ at v mod]ate dep?s only1 if !y 7 n kept 9 a solid /ate by ! prodigi\s loads :i* !y su/a94 ,any relief f ?is load %\ld at once result 9 fusion ( ! rock4 ,illu/ration3 ,,fig4 #aeb4--;,diagram to illu/rate a probable cause ( =mation ( lava res]voirs1 & to %[ ! connection betwe5 su* res]voirs & ! volcanoes at ! surface4 ,n[ ! re/riction ( active volcanoes to ^? zones ( ! e>?'s surface )9 :i* m\nta9s are ris+1 & :]e 9 consequ5ce e>?quakes are felt1 has furni%$ u at lea/ a clew to ! orig9 ( ! lava4 ,reg>d$ z a /ructure capable ( su/a9+ a load1 ! compet5cy ( an ar* is some?+ q rem>kable1 s t ! ar*+ up ( /rong rock =mations into anticl9es )9 ! upp] lay]s ( ! zone ( fl[1 or ( comb9$ fracture & fl[1 w\ld be suffici5t to remove ! load f relatively weak und]ly+ b$s1 :i* 9 consequ5ce w\ld be fus$ & =m local res]voirs ( lava 7,figs4 #aeb & #aec74 ,x has be5 fur!r q g5]ally obs]v$ t l9es ( volcanoes1 9 s f> z !y betray any relation 9 position to neighbor+ m\nta9 ranges1 t5d to appe> ^u ! re> or flatt] limb ( unsymmetrical ar*es1 or :]e local t5sion w\ld favor ! op5+ ( *annels t[>d ! surface4 ,moreov]1 :]ev] rec5t block movem5ts ( surface portions ( ! e>?'s %ell h be5 disclos$ 9 ! neighborhood ( volcanoes1 ! latt] appe> to be connect$ ) d[n?r[n blocks1 z ?\gh ! lava _h1 s to speak1 be5 squeez$ out f b5ea? ! depress$ block or blocks4 ,illu/ration3 ,,fig4 #aec4--,result ( exp]im5t ) lay]s ( composition to illu/rate ! effect ( relief ( load ^u rocks by ar*+ ( compet5t =mation 7aft] ,willis74 ,we mu/ n1 h[ev]1 =get t ! igne\s rocks are greatly re/rict$ 9 ! range ( _! *emical composition4 ,no igne\s rock type is kn[n :i* c\ld be =m$ by ! fusion ( any ( ! c>bonate rocks su* z lime/one or dolomite1 or ( ! m silice\s rocks1 su* z s&/one or qu>tzite4 ,!re rema9s only ! argillace\s class ( s$im5ts1 ! %ales & slates1 & s soon z we exam9e ! composition ( ^! rocks we are /ruck by ! rem>kable resemblance to t ( ! class ( igne\s rocks4 ,= purposes ( comp>ison !re is giv5 bel[ ! composite or av]age con/itution ( igne\s rocks 9 p>allel column1 ) ! av]age atta9$ by comb9+ ! analyses ( #ef slates & %ales1 ! latt] recalculat$ ) wat] exclud$3 ,,av]age ,,igne\s ,,rock ---------------------------------------- -------------------------- ,,av]age ,,%ale 7,cl>k7 7,wa%+ton7 ---------------------------------------- ---------------------------------------- ---------------------------------------- ------ ,si,o#b #fa4be #fa4fi #fc4cd ,al#b,o#c #ae4ha #ae4id #af4ef ,fe#b,o#c #b4gj #f4ca #a4hh #d4ec #d4da #g4hi ,fe,o #c4fa #b4fe #c4dh ,mg,o #d4dg #d4ij #c4ed ,ca,o #e4jc #e4jb #c4cc ,na#b,o #c4fd #d4ji #a4bi ,k#b,o #b4hg #c4ce #c4eb ,ti,o#b 4#fb 4#dh 4#ec ------------ ------------ ------------ #ajj4jj #ajj4jj #ajj4jj ,?is close resemblance is probably ( deep significance1 = ! reason t %ales & slates are /ructurally ! weake/ ( all rocks & = ! fur!r reason t !y r g5]ally directly und]lie ! c>bonate rocks1 :i* are by contra/ ! /ronge/ 7see ante1 p4 #cg74 ,= ^! reasons %ales & slates are ! only rocks :i* are likely to be fus$ by relief f load ?r\gh ! =mation ( anticl9al ar*es )9 ! e>?'s zone ( fl[4 ,if ?is view is well f\nd$1 lavas & o!r igne\s rocks are 9 l>ge "p fus$ argillace\s s$im5ts =m$ 9 connection ) ! process ( fold+1 or are refus$ rocks ( igne\s orig9 & simil> composition4 ,"* pr(iles4--,! "* pr(iles ( features connect$ 9 _! orig9 ) volcanoes are p>ticul>ly easy to recognize1 & 9 a few cases 9 :i* !y might be confus$ ) o!rs ( a diff]5t orig91 an exam9ation ( ! mat]ials ( ! features %\ld lead to a def9itive judgm5t4 ,! lava pla9s :i* result f massive outfl[s ( basalt might p]haps /rictly be reg>d$ z lack ( feature1 s great may be _! cont9u\s ext5t4 ,:]ev] def9ite v5ts exi/1 a broad flat dome is ! usual result ( ! extravasation ( a basaltic lava4 ,! puys ( ,france & _m ( ! ,kupp5 ( ,g]many1 be+ =m$ f less fluid lava1 h af=d$ pr(iles ) relatively small radius ( curvature4 ,9 its y\?ful /age1 ! c9d] cone usually pres5ts a broad summit sag & relatively %ort side slopes1 :]eas ! cone ( lat] /ages is apt to pres5t long sweep+ & upw>dly concave curves ) bo? ! gradi5t & ! radius ( curvature increas+ rapidly t[>d ! summit4 ,9 contra/1 too1 ) ! e>li] /age1 ! cre/ is relatively small4 ,a m>k$ r$uction 9 ! high symmetry ( su* pr(iles is not$ :]ev] a brea*+ by lava outfl[ has occurr$ 7,fig4 #aed74 ,) ! composite cone1 complexity & correspond+ lack ( symmetry is introduc$1 especially 9 ! p>tially ru9$ cald]a1 & by ! m or less accid5tal di/ribution ( p>asitic cones1 z well z by migrations ( ! c5tral cone4 ,peculi>ly simil> acum9at$ pr(iles result f spatt]-cone =mation1 f ! =mation ( a sup]*imney sp9e1 & by ! uncov]+ ( ! *imney ?r\gh d5udational processes--! volcanic neck4 ,illu/ration3 ,,fig4 #aed4--;,"* pr(iles connect$ ) volcanoes4 ,ano!r important feature result+ f d5udation is ! ,mesa or table m\nta9 ) its protect+ basalt cap above s(t] rocks4 ,its pr(ile mo/ resembles t ( table m\nta9s due to diff]5tial erosion ( alt]nately /rong & weak horizontally b$d$ rocks1 su* z compose ! upp] portion ( ! section 9 ! ,gr& ,caon ( ! ,colorado4 ,"h1 h[ev]1 9 place ( a s+le unusually /rong top lay] !re are f\nd sev]al /rong lay]s 9 alt]nation ) weak] ones s z to produce additional /eps 9 ! pr(ile4 ,,read+ ,,ref]5ces ,,to ,,*apt]s ,,ix ,,& ,x ,g5]al works3-- ,,paulett ,,scrope4 ,! ,geology ( ! ,ext9ct ,volcanoes ( ,c5tral ,france4 ,john ,murray1 ,london1 #aheh1 pp4 #beh4 7,an epo*-mak+ "w ( e>ly date :i*1 l ! foll[+ ref]5ce1 may be /udi$ to advantage to-day47 ,,sir ,,*>les ,,lyell4 ,pr9ciples ( ,geology1 vol4 #a1 ,*apt]s xxiii-xxv4 ,,mel*ior ,,neumayr4 ,erdges*i*te1 vol4 #a1 ,allgeme9e ,geologie1 revis$ edition by v4 ,uhlig1 #ahig1 pp4 #acc-bgg 7a /oreh\se ( valuable in=mation cle>ly pres5t$74 ,j4 ,d4 ,,dana4 ,*>act]i/ics ( ,volcanoes1 ) ,contributions ( ,facts & ,pr9ciples f ! ,hawaiian ,isl&s4 ,dodd1 ,mead1 & ,company1 ,new ,york1 #ahij1 pp4 #cig4 ,,tempe/ ,,&]son4 ,volcanic ,/udies 9 ,_m ,l&s1 be+ reproductions ( photographs by ! au?or ) explanatory notes4 ,john ,murray1 ,london1 #aijc1 pp4 #bjj1 pls4 #aje4 ,t4 ,g4 ,,bonney4 ,volcanoes1 _! ,/ructure & ,significance4 ,john ,murray1 ,london1 #ahii1 pp4 #cca4 ,i4 ,c4 ,,russell4 ,volcanoes ( ,nor? ,am]ica4 ,macmillan1 ,new ,york1 #ahig1 pp4 #cdf4 ,,elis,e ,r,,clus4 ,les volcans de la t]re1 ,belgian ,society ( ,a/ronomy1 ,meteorology1 & ,physics ( ! ,globe1 #aijf-aiaj 7a valuable descriptive geographical & bibliographical "w ( ref]5ce74 ,g4 ,,m]calli4 ,i vulcani attivi della t]re4 ,hoepli1 ,milan1 #aijg1 pp4 #dba4 7,a mo/ valuable "w1 beautifully illu/rat$1 b 9 ! ,italian language47 ,arrangem5t ( volcanic v5ts3-- ,,?4 ,,?orodds54 ,die ,bru*l9i5 und ihre ,beziehung5 zu d5 ,vulkan51 ,pet4 ,mitt41 vol4 #ea1 #aije1 pp4 #a-e1 pl4 #e4 ,r4 ,d4 ,m4 ,,v]beek4 ,v>i\s volumes & atlases ( maps cov]+ ! ,dut* ,ea/ ,indies & fully cit$ 9 ! foll[+ ref]5ce 7p4 #ba74 ,,william ,h4 ,,hobbs4 ,! ,evolution & ! ,outlook ( ,seismic ,geology1 ,proc4 ,am4 ,phil4 ,soc41 vol4 #dh1 #aiji1 pp4 #ag-bg4 ,bir? ( volcanoes3-- ,f4 ,,omori4 ,! ,usu-san ,eruption & ,e>?quake & ,elevation ,ph5om5a1 ,bull4 ,e>?q4 ,inv4 ,com41 ,japan1 vol4 #e1 ,no4 #a1 #aiaa1 pp4 #a-cg1 pls4 #a-ac4 ,fissure eruptions3-- ,,?4 ,,?orodds54 ,isl&1 ,,iv1 ,vulkane1 ,pet4 ,mitt41 ,ergnzung%4 #aec1 #aijf1 pp4 #ajh-aaa4 ,a4 ,,geikie4 ,text-book ( ,geology1 #d? ed41 pp4 #cdb-cdf4 ,lava domes ( ,hawaii3-- ,j4 ,d4 ,,dana4 ,*>act]i/ics ( ,volcanoes 7z above74 ,c4 ,h4 ,,hit*cock4 ,hawaii & ,its ,volcanoes4 ,honolulu1 #aiji1 pp4 #cad4 ,eruption ( ,matavanu volcano 9 #aijf3-- ,,k>l ,,sapp]4 ,d] ,matavanu-,ausbru* auf ,savaii1 #aije-aijf1 ,zeit4 d4 ,gesell4 f4 ,erdk4 z4 ,b]l91 vol4 #ai1 #aijf1 pp4 #fhf-gji1 #d pls4 ,h4 ,j4 ,,j5s54 ,! ,geology ( ,samoa1 & ! ,eruptions 9 ,savaii1 ,proc4 ,l9n4 ,soc41 ,new ,s\? ,wales1 vol4 #ca1 #aijf1 pp4 #fda-fgb1 pls4 #ed-fd4 ,,tempe/ ,,&]son4 ,! ,volcano ( ,matavanu 9 ,savaii1 ,qu>t4 ,j\r4 ,geol4 ,soc41 ,london1 vol4 #ff1 #aiaj1 pp4 #fba-fci1 pls4 #de-eb4 ,eruption ( ,volcano 9 #ahhh3-- ,h4 ,j4 ,,john/on-,,lavis4 ,! ,s\? ,italian ,volcanoes4 ,naples1 #ahia1 pp4 #cdb1 pls4 #af4 ,eruption ( ,taal volcano 9 #aiaa3-- ,w4 ,e4 ,,pratt4 ,! ,eruption ( ,taal ,volcano1 ,janu>y #cj1 #aiaa1 ,phil4 ,j\r4 ,sci41 vol4 #f1 ,no4 #b1 ,sec4 ,a1 #aiaa1 pp4 #fc-hf1 pls4 #a-ad4 ,f4 ,h4 ,,noble4 ,taal ,volcano1 album ( views ( #aiaa eruption1 ,manila1 #aiaa1 pp4 #a-dh4 ,! volcano ( ,etna3-- ,g4 ,,vom ,,ra?4 ,d] ,aetna4 ,bonn1 #ahgb1 pp4 #a-cc4 7,a beautiful piece ( descriptive writ+ f bo? ! geological & sc5ic /&po9ts47 ,,s>torius ,,von ,,walt]%aus54 ,d] ,aetna4 ,leipzig1 #ahhj1 #b qu>to vols41 pp4 #cga & #edh4 ,! eruption ( ,vesuvius 9 #aijf3-- ,h4 ,j4 ,,john/on-,,lavis4 ,geological ,map ( ,monte ,somma & ,vesuvius1 ) a %ort & concise acc\nt1 etc4 ,geo4 ,philip ,son1 ,london1 #ahia4 ,h4 ,j4 ,,john/on-,,lavis4 ,! ,eruption ( ,vesuvius 9 ,april1 #aijf1 ,trans4 ,roy4 ,dubl9 ,soc41 vol4 #i1 #aiji1 ,pt4 ,,viii1 pp4 #aci-bjj1 pls4 #c-bc 7! mo/ au?oritative "w ^u ! subject74 ,t4 ,a4 ,,jagg>1 ,,jr4 ,! ,volcano ,vesuvius 9 #aijf1 ,te*4 ,qu>t41 vol4 #ai1 #aijf1 pp4 #aje-aae4 ,w4 ,,pr9z4 ,l'ruption du ,vesuv d'avril1 #aijf1 ,ciel et ,t]re1 #bg;e ,anne1 #aijf1 pp4 #a-di4 ,,frank ,a4 ,,p]ret4 ,notes on ! ,electrical ,ph5om5a ( ! ,vesuvian ,eruption1 ,april1 #aijf1 ,sci4 ,bull41 ,brooklyn ,in/4 ,arts & ,sci41 vol4 #a1 ,no4 #aa1 pp4 #cjg-cab2 ,vesuvius1 ,*>act]i/ics & ,ph5om5a ( ! ,pres5t ,repose ,p]iod1 ,am4 ,j\r4 ,sci41 vol4 #bh1 #aiji1 pp4 #dac-dcj4 ,,william ,h4 ,,hobbs4 ,! ,gr& ,eruption ( ,vesuvius 9 #aijf1 ,j\r4 ,geol41 vol4 #ad1 #aijf1 pp4 #fcf-fee4 ,! sp9e ( ,pele3-- ,e4 ,o4 ,,hovey4 ,! ,new ,cone ( ,mont ,pele & ! ,gorge ( ! ,rivire ,blan*e1 ,m>t9ique1 ,am4 ,j\r4 ,sci41 vol4 #af1 #aijc1 pp4 #bfi-bha1 pls4 #aa-ad4 ,a4 ,,heilpr94 ,! ,t[] ( ,pele4 ,philadelphia1 #aijd1 pp4 #fb1 pls4 #bb4 ,a4 ,,lacroix4 ,la montagne ,pele et ses ruptions1 ,acad4 des ,sci5ces1 ,p>is1 #aijd1 ,*apt] iii4 ,,k>l ,,sapp]4 ,9 d5 ,vulkangebiet5 ,mittelam]ikas und ,we/9di5s1 ,/uttg>t1 #aije1 pp4 #agb-agh4 ,a4 ,c4 ,,lane4 ,absorb$ ,gases ( ,vulcanism1 ,sci5ce1 ,n4,s41 vol4 #ah1 #aijc1 p4 #gfj4 ,g4 ,k4 ,,gilb]t4 ,! ,me*anism ( ! ,mont ,pele ,sp9e1 ibid41 vol4 #ai1 #aijd1 pp4 #ibg-ibh4 ,i4 ,c4 ,,russell4 ,pele ,obelisk once ,m1 ibid41 vol4 #ba1 #aije1 pp4 #ibd-ica4 ,! dissection ( volcanoes3-- ,j4 ,w4 ,,judd4 ,volcanoes1 ,*apt] v4 ,s4 ,,sekya & ,y4 ,,kiku*i4 ,! ,eruption ( ,b&ai-,san1 ,trans4 ,seis4 ,soc41 ,japan1 vol4 #ac1 ,pt4 #b1 #ahij1 pp4 #adj-bbb1 pls4 #a-i4 ,r4 ,d4 ,m4 ,,v]beek4 ,krakatau4 ,batavia1 #ahhe1 pp4 #eeg1 pls4 #be4 ,,royal ,,society4 ,! ,eruption ( ,krakatoa & ,subsequ5t ,ph5om5a4 ,london1 #ahhh1 pp4 #did4 ,g4 ,k4 ,,gilb]t4 ,report on ! ,geology ( ! ,h5ry ,m\nta9s1 ,u4,s4 ,geogr4 & ,geol4 ,surv41 ,rocky ,mt4 ,region1 ,wa%+ton1 #ahgg1 pp4 #bb-fj4 ,,sir ,a4 ,,geikie4 ,anci5t ,volcanoes ( ,great ,brita91 vol4 #b especially4 ,d4 ,w4 ,,johnson4 ,volcanic ,necks ( ! ,m\nt ,taylor ,region1 ,new ,mexico1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ah1 #aijg1 pp4 #cjc-cbd1 pls4 #be-cj4 ,,*apt] ,,xi ,,! ,,attack ,,( ,,! ,,wea!r ,! two contra/$ processes ( wea!r+4--,x has already be5 po9t$ out t *ange & n /ability is ! ord] ( nature4 ,)9 ! e>?'s out] %ell & ^u x rock alt]ation goes on cont9ually1 & f "s portions ( its surface ! *ang$ mat]ial is z con/antly migrat+ to neighbor+ or ev5 f> di/ant regions4 ,be=e su* transportation c beg9 ! h>d rock mu/ fir/ be brok5 d[n & r$uc$ to fragm5ts :i* ! transport+ ag5cies are compet5t to move4 ,to accompli% ?is break+ d[n1 or deg5]ation1 ( ! rock masses1 ei!r a wide range 9 temp]ature or *emical reaction is ess5tial4 ,9 ! atmosph]e are f\nd su* active *emical ag5ts z oxyg5 & c>bon dioxide1 ! s-call$ c>bonic acid gas2 & ^! ag5ts 9 ! pres5ce ( wat] react *emically ) ! m9]als ( ! rocks & =m o!r m9]als su* z ! hydrates & c>bonates1 :i* are light] 9 weight & m soluble4 ,?is *emical attack ^u ! out] %ell ( ! li?osph]e is describ$ z decomposition4 ,on ! o!r h& ! rock may succumb to *anges :i* are purely me*anical & are due ei!r to ! /resses set up by diff]5ces betwe5 surface & int]ior temp]atures1 or to ! pry+ action ( ! fro/ 9 ! crevices4 ,su* purely me*anical deg5]ation ( ! rocks is 9 contra/ ) decomposition & is describ$ z dis9tegration4 ,! two processes ( decomposition & dis9tegration may1 h[ev]1 g on toge!r2 & ! *anges ( volume t are caus$ by decomposition may result directly 9 consid]able dis9tegration1 z we are to see4 ,! rle ( ! p]colat+ wat]4--,9 ord] to effect *emical *ange or reaction1 x is ess5tial t ! sub/ances :i* are to react mu/ be br\ght into su* intimate contact ) ea* o!r z x is seldom possible to atta9 except by solution4 ,! *emical reactions :i* g on betwe5 ! gase\s atmosph]e & ! solid li?osph]e are accompli%$ ?r\gh solution ( ! gases 9 wat]4 ,?is wat]1 d]iv$ f ra9 or sn[1 p]colates into ! gr\nd or desc5ds along ! crevices 9 ! rocks1 c>ry+ ) x a c]ta9 measure ( dissolv$ air4 ,?is air diff]s f t ( ! surr\nd+ atmosph]ic envelope by conta9+ relatively l>ge am\nts ( oxyg5 & ( ! o!r active elem5t c>bon dioxide4 ,x foll[s f ! important rle ?us p]=m$ by ! p]colat+ wat] t ! process ( decomposition w be relatively important 9 humid regions :]e ! atmosph]ic precipitation is suffici5t = ! purpose4 ,illu/ration3 ,,fig4 #aee4--,successive diagrams to %[ ! effect ( decomposition & result+ dis9tegration ^u jo9t blocks s z to produce sph]oidal b[ld]s by wea!r+4 ,)9 hot & dry regions !re is a l>g] measure ( rock dis9tegration1 & di/9ct *emical *anges unlike ^? ( humid regions take place 9 ! high] temp]atures & ) ! m conc5trat$ sal9e solutions4 ,! discussion ( su* *anges w be def]r$ until des]t conditions are treat$ 9 ano!r *apt]4 ,me*anical results ( decomposition--sph]oidal wea!r+4--,f an e>li] *apt] x has be5 le>n$ t ! rocks ( ! e>?'s out]mo/ %ell are g5]ally int]sect$ by a sy/em ( v]tical fissures :i* at ea* locality t5d to divide ! rock into p>allel & upright rectangul> prisms4 ,x is ^! jo9ts :i* (f] relatively easy pa?s = ! desc5t ( ! wat] into ! rocks4 ,9 rocks ( s$im5t>y orig9 !re are f\nd1 9 addition to ! v]tical jo9ts1 planes ( b$d+ orig9ally horizontal1 & 9 ! intrusive & volcanic rocks a some:at simil> p>t+1 likewise p>allel to ! surface ( ! gr\nd4 ,! comb9$ effect ( ! jo9ts & ! additional p>t+ planes is ?us to sep>ate ! rock mass into m or less p]fect squ>$ blocks 7,fig4 #aee1 upp] figure7 :i* /& 9 v]tical columns4 ,! wat] :i* p]colates d[nw>d ^u ! jo9ts1 f9ds its way lat]ally along ! p>t+ planes1 & s subjects ! entire surface ( ea* block to simultane\s attack by its reag5ts4 ,?\gh all p>ts ( ! surface ( ea* block are alike subject to attack1 x is ! angles & ! edges :i* are mo/ vigor\sly act$ ^u4 ,9 ! n>r[ crevices ! solutions move b sluggi%ly1 & z !y are soon impov]i%$ ( _! reag5ts 9 ! attack ^u ! rock1 fre% solution c rea* ! middle ( ! faces f relatively few directions4 ,! edges are at ! same "t be+ rea*$ f _m m directions1 & ! corn]s f a /ill l>g] numb]4 ,! m9]als newly =m$ by ^! *emical processes ( hydration & c>bonization are notably light]1 & h5ce m bulky ?an ! m9]als f ^: con/itu5ts !y h be5 l>gely =m$4 ,/ra9s are ?us set up :i* t5d to sep>ate ! bulki] new mat]ial f ! core ( unalt]$ rock bel[4 ,z ! process cont9ues1 di/9ct *annels = ! mov+ wat]s are develop$ favorable to action at ! edges & corn]s ( ! blocks4 ,ev5tually1 ! squ>$ block is by ?is process trans=m$ into a sph]oidal core ( /ill unalt]$ rock wrapp$ 9 lay]s ( decompos$ mat]ial1 l ! out] wrapp+s ( an onion4 ,^! 9 turn are usually imb$d$ 9 m ?or\ghly dis9tegrat$ mat]ial f :i* ! %ell /ructure has disappe>$ 7,fig4 #aef74 ,illu/ration3 ,,fig4 #aef4--,sph]oidal wea!r+ ( an igne\s rock4 ,exfoliation or scal+4--,a fact ( mu* importance to geologi/s1 b "o f> too (t5 ov]look$1 is t rocks are b poor conductors = heat4 ,x results f ?is t 9 ! bright sun ( a summ]'s day a ?9 sk91 z x 71 ^u ! rock surface may be heat$ to a relatively high temp]ature1 al?\gh ! lay] imm$iately bel[ x is practically unaffect$4 ,! consequ5t expansion ( ! surface lay] causes /resses t t5d to scale x (f f ! lay] bel[1 :i*1 uncov]$ 9 its turn1 develops new /ra9s ( ! same sort4 ,?is process ( exfoliation acquires exceptional importance 9 des]t regions :]e ! rock surfaces are daily elevat$ to excessively high temp]atures 7see ,*apt] ,,xv74 ,illu/ration3 ,,fig4 #aeg4--;,dome /ructure 9 granite mass1 ,yosemite valley1 ,cali=nia 7aft] a photograph by ,s9clair74 ,dome /ructure 9 granite masses4--,9 l>ge granite masses1 su* z are to be f\nd 9 ! ranges ( ! ,si]ra ,nevada ( ,cali=nia1 a peculi> dome /ructure is sometimes f\nd develop$ ^u a l>ge scale1 & has _h an important influ5ce ^u ! break+ d[n ( ! rock & ^u ! %ap+ ( ! m\nta9 7,fig4 #aeg74 ,su* a /ructure1 made up z x is ( prodigi\s lay]s1 c h little 9 common ) ! v5e]s ( wea!r$ m9]als :i* are ! result ( exfoliation1 & x is q likely t ! dome /ructure is 9 "s way connect$ ) ! relief ( ^! massive rocks f _! load--! rock :i* once re/$ ^u !m1 b has be5 c>ri$ away by erosion s9ce ! uplift ( ! range4 ,! pry+ "w ( fro/4--,9 all c\ntries :]e w9t] temp]atures range bel[ ! freez+ po9t ( wat]1 a mo/ pot5t ag5t ( rock dis9tegration is ! fro/ :i* pries at e crevice & cranny ( ! surface rock4 ,important 9 ! temp]ate zones1 9 ! pol> regions x becomes almo/ ! sole effective ag5t ( rock wea!r+4 ,!re1 z else:]e1 its effici5cy z a dis9tegrat+ ag5t is directly dep5d5t ^u ! nature ( ! crevices )9 ! rock1 s t ! omnipres5t jo9ts are able to ex]cise a degree ( control ov] ! sculptur+ ( ! surface features :i* is h>dly to be look$ = else:]e 7see plate #aj ,a74 ,illu/ration3 ,,fig4 #aeh4--,talus slope b5ea? a cliff4 ,talus4--,:]ev] ! e>?'s surface rises 9 /eep cliffs1 ! rock fragm5ts d]iv$ f fro/ action1 or by o!r processes ( dis9tegration1 z !y become deta*$ ei!r fall or slide rapidly d[nw>d until arre/$ ^u a flatt] slope4 ,^u ! e>li] accumulations ( ?is k9d1 ! lat] ones are deposit$1 until _! surface slopes up to ! cliff face z /eeply z ! mat]ial w lie--! angle ( repose4 ,su* dbris accumulations at ! base ( a cliff 7,fig4 #aeh7 are kn[n z talus1 & ! slope is describ$ z a talus slope1 or 9 ,scotl& z a 8scree40 ,illu/ration3 ,,fig4 #aei4--,/rip$ gr\nd f soil fl[ ( *ipp$ rock fragm5ts ^u a slope1 ,sn[ ,hill ,isl&1 ,we/ ,ant>ctica 7aft] ,otto ,nord5skild74 ,soil fl[ 9 ! cont9u$ pres5ce ( ?aw wat]4--,s soon z ! rocks are brok5 d[n by ! wea!r+ processes1 !y are easily mov$1 usually to l[] levels4 ,9 "p ?is transportation may be accompli%$ by gravity sl[ly act+ ^u ! dis9tegrat$ rock & caus+ x to creep d[n ! slope4 ,yet ev5 9 su* cases wat] is usually pres5t 9 quantity suffici5t to fill ! spaces betwe5 ! gra9s1 & s act z a lubricant to facilitate ! migration4 ,^u a l>ge scale rocks :i* 7 ei!r orig9ally incoh]5t or h be5 made s by wea!r+1 aft] !y h become saturat$ ) wat]1 may />t into sudd5 motion z great l&slides or avalan*es1 :i* 9 ! space ( a few mom5ts mat]ially *ange ! face ( ! c\ntry1 & by bury+ ! bottom l&s leave disa/] & mis]y 9 _! wake4 ,illu/ration3 ,,fig4 #afj4--,pavem5t ( horizontal surface due to soil fl[1 ,spitzb]g5 7aft] ,otto ,nord5skild74 ,)9 ! subpol> regions1 :]e a l>ge "p ( ! surface is = mu* ( ! ye> cov]$ ) sn[1 ! und]ly+ rocks are = long p]iods saturat$ ) ?aw wat]1 & 9 alt]nation are repeat$ly froz5 & ?aw$4 ,ess5tially simil> conditions are met ) 9 ! high1 sn[-capp$ m\nta9s ( temp]ate or torrid regions4 ,= ! subpol> regions p>ticul>ly x is n[ g5]ally recogniz$ t some:at special processes ( soil fl[1 describ$ "u ! "n solifluction1 are *>act]i/ic4 ,! exact nature ( ^! processes is z yet imp]fectly und]/ood1 b !re c be little d\bt conc]n+ ! l>ge rle :i* !y h play$ 9 ! transportation ( surface mat]ials4 ,su* soil fl[ is cle>ly manife/$ "u diff]5t aspects1 & x is likely t by ?is compreh5sive t]m di/9ct processes h be5 br\ght toge!r4 ,illu/ration3 ,,fig4 #afa4--,tree roots ent]+ fissur$ rock & pry+ its sections ap>t4 ,possibly ! mo/ /rik+ aspect ( ! soil fl[ 9 subpol> regions is furni%$ by ! rem>kable 8/one riv]s0 & 8rock glaci]s02 ?\gh ! m g5]ally *>act]i/ic are peculi> /rip+s or o!r m>k+s :i* appe> ^u ! surface ( ! gr\nd & ?us betray ! movem5ts ( ! und]ly+ mat]ials4 ,^u slopes x is n uncommon = ! surface to be compos$ ( angul> rock fragm5ts riv5 by ! fro/ & cross$ by broad p>allel furr[s z ?\gh a gigantic pl[ _h gone ov] x 7,fig4 #aei74 ,! direction ( ! furr[s is always up & d[n ! slope1 & ! /rip+ is m>k$ 9 proportion z ! slope is /eep4 ,:]e ! bottom is rea*$1 ! furr[s are replac$ by a sort ( mosaic pavem5t ( hexagonal repeat+ figures1 ea* ( :i* may be an area ( ! surface six feet or m across 7,fig4 #afj1 & ,fig4 #cij1 p4 #cfh74 ,! depressions :i* sep>ate ! 8blocks0 ( ! pavem5t are (t5 fill$ ) clay1 :ile ! inclos$ surfaces are made up ( co>sely *ipp$ /one4 ,! splitt+ w$ges ( roots & trees4--,9 ! me*anical breakd[n ( ! rocks )9 humid regions a n unimportant "p is sometimes tak5 by ! trees1 :i* ins9uate ! t5u\s extremities ( _! rootlets into ! smalle/ cracks & by cont9u$ gr[? sl[ly w$ge ev5 ! firm] rocks ap>t 7,fig4 #afa74 ,9 a simil> mann] ! small tree trunk gr[+ )9 a crevice ( ! rock may 9 "t split its p>ts asund] 7,fig4 #afb74 ,illu/ration3 ,,fig4 #afb4--;,a l>ge glacial b[ld] split by a gr[+ tree ne> ,ea/ ,lans+1 ,mi*igan 7aft] a photograph by ,b]?a ,?ompson74 ,! rock mantle & its %ield 9 ! mat ( vegetation4--,?r\gh ! action ( wea!r+1 ! rocks1 z we h se51 lose _! integrity )9 a surface lay]1 :i*1 ?\gh x may be z mu* z a hundr$ feet or m 9 ?ickness1 mu/ /ill be acc\nt$ a m]e film above ! und]ly+ b$ rock4 ,! me*anical ag5ts ( ! breakd[n op]ate only )9 a few feet ( ! surface1 & ! ag5ts ( rock decomposition1 d]iv$ z !y are f ! atmosph]e1 become in]t be=e !y h desc5d$ to any consid]able dep?4 ,! surface lay] ( incoh]5t rock is usually ref]r$ to z ! rock mantle 7,fig4 #afc74 ,:]e ! rock mantle is relatively deep1 z x is 9 ! /ates s\? ( ! ,ohio 9 ! ea/]n ,unit$ ,/ates1 !re is f\nd1 deep bel[ ! out] lay] ( soil1 a p>tially decompos$ & dis9tegrat$ rock1 ( :i* ! unalt]$ m9]als lie un*ang$ 9 position b sep>at$ by ! new m9]als :i* h result$ f ! breakd[n ( _! m susceptible associates4 ,:ile ?us 9 a c]ta9 s5se possess+ ! orig9al /ructure1 ?is alt]$ mat]ial is ess5tially incoh]5t & easily succumbs to attack by ! pick & spade1 s t x is only at consid]ably great] dep?s t ! unalt]$ rock is enc\nt]$4 ,illu/ration3 ,,fig4 #afc4--,rock mantle consi/+ ( brok5 rock1 above :i* is soil & a vegetable mat4 ,coa/ ( ,cali=nia 7aft] a photograph by ,fairbanks74 ,because ( ! t5d5cy ( mantle rock to creep d[n ^u slopes x is g5]ally f\nd ?ick] ^u ! cre/s & at ! bases ( hills & ?9ne/ ^u _! slopes 7,fig4 #afd74 ,9 ! trans=mation ( ! upp] portion ( ! mantle rock into soil1 additional *emical processes to ^? ( wea!r+ are c>ri$ ?r\gh by ! ag5cy ( e>?worms1 bact]ia1 & o!r organisms1 & by ! action ( humus & o!r acids d]iv$ f ! decomposition ( vegetation4 ,! bact]ia p>ticul>ly play a "p 9 ! =mation ( c>bonates1 z !y d also 9 *ang+ ! nitrog5 ( ! air into nitrates :i* become available z plant food4 ,)9 ! humid tropical regions ants & o!r insects ent] z a l>ge factor 9 rock decomposition1 z !y d also 9 produc+ n unimportant surface irregul>ities4 ,illu/ration3 ,,fig4 #afd4--;,diagram to %[ ! v>y+ ?ickness ( mantle rock ^u ! diff]5t portions ( a hill surface 7aft] ,*amb]l9 & ,salisbury74 ,h[ important is ! cov] ( vegetation 9 reta9+ ! rock mantle & ! upp] soil lay] 9 _! respective positions1 z requir$ = agricultural purposes1 may be be/ illu/rat$ by ! disa/r\s consequ5ces ( all[+ x to be de/roy$4 ,:]ev]1 by ! de/ruction ( =e/s1 by ! excessive graz+ ( animals1 or by o!r causes1 ! mat ( turf has be5 de/roy$1 ! surface is op5$ 9 gullies by ! fir/ h>d ra91 & ! f]tile lay] ( soil is c>ri$ f ! slopes & di/ribut$ ) ! co>s] mantle ^u ! bottom l&s4 ,?us ! face ( ! c\ntry is completely trans=m$ f f]tile hills into ! mo/ desolate ( des]ts :]e no spe> ( grass is to be se5 & no animal food to be obta9$ 7plate #e ,a74 ,! soil once wa%$ away is n aga9 r5ew$1 = ! cont9uation ( ! gully+ process n[ effectively prev5ts its accumulation4 ,,plate #e4 ,illu/ration3 ,a4 ,once wood$ region 9 ,*9a n[ r$uc$ to des]t ?r\gh de=e/ation 7aft] ,willis74 ,illu/ration3 ,b4 8,bad ,l&s0 9 ! ,colorado ,des]t 7aft] ,m5d5hall74 ,,read+ ,,ref]5ces ,,to ,,*apt] ,,xi ,decomposition & dis9tegration3-- ,,george ,p4 ,,m]rill4 ,! ,pr9ciples ( ,rock ,wea!r+1 ,j\r4 ,geol41 vol4 #d1 #ahif1 pp4 #gjd-gbd1 #hej-hga4 ,rocks1 ,rock ,wea!r+1 & ,soils4 ,macmillan1 ,new ,york1 #ahig1 ,pt4 iii1 pp4 #agb-daa4 ,,alexis ,a4 ,,juli54 ,on ! ,geological ,action ( ! ,humus ,acids1 ,proc4 ,am4 ,assoc4 ,adv4 ,sci41 vol4 #bh1 #ahgi1 pp4 #caa-daj4 ,corrosion ( rocks3-- ,c4 ,w4 ,,hayes4 ,solution ( ,silica "u ,atmosph]ic ,conditions1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #h1 #ahig1 pp4 #bac-bbj1 pls4 #ag-ai4 ,m4 ,l4 ,,full]4 ,et*+ ( ,qu>tz 9 ! ,int]ior ( ,conglom]ates1 ,j\r4 ,geol41 vol4 #aj1 #aijb1 pp4 #hae-hba4 ,c4 ,h4 ,,smy?1 ,,jr4 ,replacem5t ( ,qu>tz by ,pyrites & ,corrosion ( ,qu>tz ,pebbles1 ,am4 ,j\r4 ,sci4 7#d71 vol4 #ai1 #aije1 pp4 #bhb-bhe4 ,dome /ructure ( granite masses3-- ,g4 ,k4 ,,gilb]t4 ,domes & ,dome ,/ructure ( ! ,high ,si]ra1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ae1 #aijd1 pp4 #bi-cf1 pls4 #a-d4 ,,ralph ,,arnold4 ,dome ,/ructure 9 ,conglom]ate1 ibid41 vol4 #ah1 #aijg1 pp4 #fae-faf4 ,soil fl[3-- ,j4 ,,gunn> ,,&]sson4 ,solifluction1 a ,compon5t ( ,subarial ,d5udation1 ,j\r4 ,geol41 vol4 #ad1 #aijf1 pp4 #ia-aab4 ,,otto ,,nord5ski,,ld4 ,die ,pol>welt und ihre ,na*b>lnd]1 ,leipzig1 #aiji1 pp4 #fj-fe4 ,,erne/ ,,h[e4 ,l&slides 9 ! ,san ,juan ,m\nta9s1 ,colorado1 etc41 ,pr(4 ,pap41 #fg ,u4 ,s4 ,geol4 ,surv41 #aiji1 pp4 #a-eh1 pls4 #a-bj4 ,g4 ,e4 ,,mit*ell4 ,l&slides & ,rock ,avalan*es1 ,nat4 ,geogr4 ,mag41 vol4 #ba1 #aiaj1 pp4 #bgg-bhg4 ,,william ,h4 ,,hobbs4 ,soil ,/ripes 9 ,cold ,humid ,regions & a ,k9dr$ ,ph5om5on1 #ab? ,rept4 ,mi*4 ,acad4 ,sci41 #aiaj1 pp4 #ea-ec1 pls4 #a-b4 ,relation ( de=e/ation to erosion3-- ,n4 ,s4 ,,%al]4 ,orig9 & ,nature ( ,soils1 #ab? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahia1 ,pt4 #a1 pp4 #bfh-bhg4 ,w4 ,j4 ,,mcgee4 ,! ,lafayette ,=mation1 ibid41 pp4 #dcj-ddh4 ,f4 ,h4 ,,k+4 ,soils4 ,macmillan1 ,new ,york1 #aijh1 pp4 #ej-ed4 ,,bailey ,,willis4 ,wat] ,circulation & ,its ,control1 ,rept4 ,nat4 ,cons]v4 ,com41 #aiji1 vol4 #b1 pp4 #fhg-gaj4 ,w4 ,j4 ,,mcgee4 ,soil erosion1 ,bull4 #ga1 ,u4 ,s4 ,bureau ( ,soils1 #aiaa1 pp4 #fj1 pls4 #cc4 ,,*apt] ,,xii ,,! ,,life ,,hi/ories ,,( ,,riv]s ,! intricate patt]n ( riv] et*+s4--,! attack ( ! wea!r ^u ! solid li?osph]e de/roys ! integrity ( its surface lay]1 & ?r\gh r$uc+ x to rock dbris makes x ! natural prey ( any ag5t compet5t to c>ry x along ! surface4 ,we h se5 h[1 = %ort di/ances1 gravity unaid$ may pile up ! dbris 9 accumulations ( talus1 & h[1 :5 assi/$ by ?aw wat] :i* has soak$ into ! mat]ial1 x may accompli% a sl[ migration by a peculi> type ( soil fl[4 ,yet f> m pot5t transport+ ag5cies are at "w1 & ( ^! ! "o ( fir/ importance is runn+ wat]4 ,only 9 ! he>ts ( great des]ts or 9 ! equally remote :ite des]ts ( ! pol> regions is ! s\nd ( its murmur+s nev] he>d4 ,e o!r "p ( ! e>?'s surface has at "s "t its runn+ wat] c\rs+ 9 valleys :i* x has itself et*$ into ! surface4 ,x is ?is et*+ out ( ! cont95ts 9 an intricate patt]n ( ana/omos+ valleys :i* con/itutes ! *ief diff]5ce betwe5 ! l& surface & ! relatively ev5 floor ( ! oceans4 ,! motive p[] ( riv]s4--,e riv] is born 9 ?roes ( ,"m ,e>? by :i* ! l& is uplift$ & left at a high] level ?an x 0 be=e4 ,x is ! diff]5ce ( elevation ?us br\ght ab\t betwe5 sep>at$ portions ( ! l& areas t makes x possible = ! wat] :i* falls ^u ! high] portions to desc5d by gravity to ! l[]4 ,?is natural 8head0 due to diff]5ces ( elevation is ! motive p[] ( ! local /reams1 & = ea* increase 9 elevation !re is an imm$iate response 9 r5ew$ vigor ( ! /reams4 ,! elevat$ area (f :i* ! riv]s fl[ is "h t]m$ an upl&4 ,! velocity ( a /ream w be dep5d5t n only ^u ! diff]5ce 9 altitude betwe5 its s\rce & its m\?1 b ^u ! di/ance :i* sep>ates !m1 s9ce ?is w det]m9e ! grade4 ,! level ( ! m\? be+ ! l[e/ :i* ! /ream c rea* is t]m$ ! base level1 & ! curr5t is fix$ by ! slope or declivity4 ,! capacity to lift & transport rock dbris is augm5t$ at a q surpris+ rate ) e increase 9 curr5t velocity1 ! law be+ t ! weight ( ! heavie/ transportable fragm5t v>ies ) ! six? p[] ( ! velocity ( ! curr5t4 ,?us if "o /ream fl[s twice z rapidly z ano!r1 x c transport fragm5ts :i* are sixty-f\r times z heavy4 ,old l& & new l&4--,! uplifts ( ! cont95ts may proce$ )\t *anges 9 ! position ( ! %ore l9es1 9 :i* case areas1 already c>v$ by /reams b no long] actively modifi$ by !m1 are work$ ^u by tools fre%ly %>p5$ & driv5 by great] p[]4 ,! l& ?us subject$ to active /ream cutt+ is describ$ z old l&1 & has already _h engrav$ ^u x ! *>act]i/ic patt]n ( riv] et*+s1 albeit ! design has be5 9 "p effac$4 ,if1 ^u ! o!r h&1 ! %ore l9e migrates seaw>d ) ! uplift1 a portion ( ! relatively ev5 sea floor1 or new l&1 is elevat$ & laid "u ! action ( ! runn+ wat]4 ,z we are to see1 /ream cutt+ is to "s ext5t modifi$ :5 a riv] patt]n is inh]it$ f ! uplift4 ,! uplift1 :e!r ( old l& only or ( bo? old l& & new l&1 m>ks ! />t+ po9t ( a new riv] hi/ory1 usually describ$ z an erosion cycle4 ,illu/ration3 ,,fig4 #afe4--,two successive =ms ( gullies f ! e>lie/ /age ( a riv]'s life 7aft] ,salisbury & ,atwood74 ,! e>li] aspects ( riv]s4--,?\gh geologi/s h sometimes reg>d$ ! uplift ( ! cont95ts z a sort ( upw>p+ 9 a cont9u\s curv$ surface1 ! discussions ( riv] hi/ories & ! pictorial illu/rations ( !m h alike cle>ly assum$ t ! uplift has be5 ess5tially 9 blocks & t ! elevat$ area meets ! l[] ly+ c\ntry or ! sea 9 a m or less def9ite esc>pm5t4 ,! fir/ riv]s to develop aft] ! uplift may be describ$ z gullies %ap$ by ! sudd5 d[nru% ( /orm wat]s & spac$ m or less regul>ly along ! m>g9 ( ! esc>pm5t 7,fig4 #afe74 ,^! gullies are relatively %ort1 /raight1 & /eep2 !y h precipit\s walls & few1 if any1 tribut>ies4 ,illu/ration3 ,,fig4 #aff4--,p>tially dissect$ upl& 7aft] ,salisbury & ,atwood74 ,) "t ! gully heads advance into ! upl& z !y take on tribut>ies2 & s at l5g? !y 9 "p inve/ x & dissect x into num]\s irregul>ly b\nd$ & flat-topp$ tables :i* are sep>at$ by caons 7,fig4 #aff74 ,at ! same "t ! grade ( ! *annel is becom+ flatt]1 & its precipit\s walls are be+ replac$ by curv+ slopes1 z w be m fully describ$ 9 ! sequel4 ,x is because ( ?is progressive r$uction ( grades ) increas+ age t ! e>ly /ages ( a riv]'s life are mu* ! mo/ turbul5t ( its hi/ory4 ,! wat] !n ru%es d[n ! /eep grades 9 rapids1 & is (t5 at times op5$ out 9 "s bas9 to =m a lake :]e diff]5ces ( uplift h be5 *>act]i/ic ( neighbor+ sections4 ,= sev]al reasons su* bas9s 9 ! c\rse ( a /ream are relatively %ort liv$ 7,*apt] ,,xxx71 & !y disappe> ) ! e>li] /ages ( ! riv] hi/ory4 ,! me%es ( ! riv] network4--,f ! cont9u$ ?r[+ out ( new tribut>ies by ! /reams1 ! me%es 9 ! riv] network draw m closely toge!r z ! /ages ( its hi/ory advance4 ,! clos5ess ( texture :i* is at la/ develop$ ^u ! upl& is 9 "p det]m9$ by ! quantity ( ra9fall1 s t 9 ,new ,j]sey ) heavy annual precipitation ! me%es 9 ! network are mu* small] ?an !y are1 = example1 ^u ! semi>id or arid pla9s ( ! we/]n ,unit$ ,/ates4 ,its design w1 h[ev]1 9 ei!r case m or less cle>ly express ! plan ( rock ar*itecture :i* is hidd5 b5ea? ! surface 7,*apt] ,,xvii74 ,! upp] & l[] rea*es ( a riv] contra/$4--,f ! fact t ! riv] progressively invades new portions ( ! upl& & lays ! acquir$ sections "u m & m ?or\gh inve/m5t1 x has ne> its headwat]s = a long "t a fronti] di/rict :i* may be reg>d$ z y\?ful ev5 ?\gh ! sections ne> its m\? h rea*$ a some:at advanc$ /age4 ,! newly acquir$ sections ( riv] valley may ?us possess ! /eep grade & precipit\s walls :i* are *>act]i/ic ( e>ly gullies & caons & are 9 contra/ ) ! m r\nd$ & flat-bottom$ sections bel[4 ,lat]al /reams1 f ! fact t !y are new] ?an ! ma9 or trunk /ream to :i* !y are tribut>y1 likewise desc5d ^u some:at /eep] grades 7,fig4 #afg74 ,illu/ration3 ,,fig4 #afg4--;,*>act]i/ic longitud9al sections ( ! upp] portion ( a riv] valley & its tribut>ies 7aft] scal$ sections by ,nussbaum74 ,! balance betwe5 degradation & aggradation4--,we h se5 t ! p[] to transport rock fragm5ts is augm5t$ at a mo/ surpris+ rate ) e increase 9 ! curr5t velocity4 ,:ile ! light] p>ticles ( rock may be c>ri$ z high up z ! surface ( ! wat]1 ! heavi] ones are mov$ =w>d ^u ! bottom ) a comb9$ roll+ & hopp+ motion aid$ by local eddies4 ,^? p>ticles :i* come 9 contact ) ! bottom or sides ( ! *annel abrade its surface s z ev] to deep5 & wid5 ! valley4 ,?is cutt+ accompli%$ by p>tially susp5d$ dbris 9 rapidly mov+ curr5ts ( wat] is kn[n z corrasion & ! /ream is said to be incis+ its valley4 ,z ! curr5t is *eck$ ^u ! l[] & flatt] grades1 "s ( its load ( s$im5t1 & especially ! co>s] portion1 w be deposit$ & s p>tially fill 9 ! *annel4 ,a nice balance is ?us e/abli%$ betwe5 degradation & ! contra/$ process kn[n z aggradation4 ,! old] ! riv] valley ! flatt] become ! grades at any section ( its c\rse1 & ?us ! po9t :i* sep>ates ! l[] zone ( aggradation f ! upp] "o ( degradation moves /eadily up/ream ) ! lapse ( "t4 ,! accordance ( tribut>y valleys4--,x is a consequ5ce ( ! great s5sitiv5ess ( /ream corrasion to curr5t velocity t no side /ream may ent] ! trunk valley at a level above t ( ! ma9 /ream--! tribut>y /reams ent] ! trunk /ream accordantly4 ,ea* has c>v$ its own valley1 & any abrupt increase 9 gradi5t ( ! side /reams ne> :]e !y ent] ! ma9 /ream w\ld h increas$ ! local corrasion at an accel]at$ rate & s h cut d[n ! *annel to ! level ( ! trunk /ream4 ,! grad+ ( ! flood pla94--,all riv]s are subject to seasonal v>iations 9 ! volume ( _! wat]s4 ,:]e !re are wet & dry seasons ^! diff]5ces are greate/1 & = a l>ge "p ( ! ye> ! valleys 9 su* regions may be empty ( wat]1 & are 9 fact (t5 utiliz$ = ?or\ghf>es4 ,9 ! temp]ate climates ( middle latitudes riv]s are g5]ally flood$ 9 ! spr+ :5 ! w9t] sn[s are melt$1 ?\gh !y may dw9dle to comp>atively small /reams dur+ ! late summ]4 ,9 ! upp] rea*es ( ! riv] ! curr5t velocities are su* t ! usual riv] *annel may c>ry all ! wat] ( flood "t2 b l[] d[n & 9 ! zone ( aggradation1 :]e ! curr5t has be5 *eck$1 ! level ( ! wat] rises 9 flood above ! banks ( its usual *annel & spreads ov] ! surr\nd+ l[l&s4 ,z a deposit ( s$im5t is spread ^u ! surface1 ! succession ( ! annual deposits f ?is s\rce raises ! g5]al level z a broad floor describ$ z ! flood pla9 ( ! riv]4 ,! cycles ( /ream me&]s4--,! annual flood+ ) wat] & simultane\s deposition ( silt is n1 h[ev]1 ! only grad+ process :i* is 9 op]ation ^u ! flood pla94 ,x is *>act]i/ic ( swift curr5ts t _! c\rse is ma9ta9$ 9 relatively /raight l9es because ( ! in]tia ( ! rapidly mov+ wat]4 ,9 proportion z _! curr5ts become sluggi%1 riv]s are turn$ aside by ! smalle/ ( ob/ructions2 & once div]t$ f _! /raight c\rse1 a law ( nature becomes op]ative :i* increases ! curvature ( ! /ream at an accel]at$ rate up to a critical po9t1 :5 by a *ange1 sudd5 & cata/rophic1 a new & direct c\rse is tak51 to be 9 its turn c>ri$ ?r\gh a simil> cycle ( *anges4 ,?is s-call$ me&]+ ( a /ream is accompani$ by a transf] ( s$im5t f "o b5d or me&] ( ! riv] to ^? bel[ & f "o bank to ! o!r4 ,inasmu* z ! lat] me&]s cross ! e>li] ones & 9 "t occupy all portions ( ! pla9 to ! same av]age ext5t1 a process ( r\gh grad+ is accompli%$ to :i* ! annual ov]fl[ deposit is supplem5t>y4 ,illu/ration3 ,,fig4 #afh4--,map & sections ( a /ream me&]4 ,! c\rse ( ! ma9 curr5t is indicat$ by ! da%$ l9e4 ,! c\rse ( ! curr5t 9 consecutive me&]s & ! cross sections ( ! *annel :i* result directly f ! me&]+ process w be made cle> f exam9ation ( ,fig4 #afh4 ,s soon z div]t$ f its direct c\rse1 ! curr5t1 by its in]tia ( motion1 is ?r[n aga9/ ! out] or convex side s z to sc\r or corrade t bank4 ,^u ! concave or inn] side ( ! curve !re is 9 consequ5ce an area ( slack wat]1 & "h ! silt sc\r$ f high] me&]s is deposit$4 ,! sc\r+ ( ! curr5t ^u ! out] bank & ! fill+ ^u ! inn] ?us gives to ! cross section ( ! /ream a g5]ally unsymmetrical "* 7,fig4 #afh ab74 ,betwe5 me&]s ne> ! po9t ( inflection ( ! curve1 & !re only1 ! curr5t is c5t]$ 9 ! middle ( ! *annel & ! cross section is symmetrical 7,fig4 #afh cd74 ,illu/ration3 ,,fig4 #afi4--,tree 9 "p und]m9$ ^u ! out] bank ( a me&]4 ,! sc\r ^u ! convex side ( a me&] causes ! riv] to sw+ ev] f>!r 9 t direction1 & ?r\gh invasion ( ! silt$ flood pla9 to migrate across x4 ,trees :i* lie 9 its pa? are und]m9$ & fall outw>d 9 ! /ream ) tops direct$ ) ! curr5t 7,fig4 #afi74 ,:5ev] ! flood pla9 is =e/$1 ! fall5 trees may be s num]\s z to lie 9 ranks along ! %ore1 & at ! "t ( ! next flood !y are c>ri$ d[n/ream to jam 9 n>r[ places along ! *annel & give ! errone\s impression t ! flood has itself uproot$ a section ( =e/ 7see p4 #dah74 ,illu/ration3 ,,fig4 #agj4--;,diagrams to %[ ! successive positions ( /ream me&]s & ! relatively /ation>y po9t ne> ! %>pe/ curvature4 ,! cut-(f ( ! me&]4--,z ! me&] sw+s t[>d its extreme position x becomes m & m closely loop$4 ,adjac5t loops ?us approa* ne>] & ne>] to ea* o!r1 b 9 ! successive positions a ne>ly /ation>y po9t is e/abli%$ ne> :]e ! riv] makes its %>pe/ turn 7,fig4 #agj1 ,g1 & ,fig4 #ded1 p4 #dag74 ,at l5g? ! neck ( l& :i* sep>ates me&]s is s n>r[ t 9 ! next fre%et a tempor>y jamm+ ( logs )9 ! *annel may direct ! wat]s across ! neck1 & once />t$ 9 ! new direction a *annel is sc\r$ out 9 ! s(t silt4 ,?us by a break+ ?r\gh ( ! bank ( ! /ream1 a s-call$ 8crevasse01 ! riv] sudd5ly /raight5s its c\rse1 ?\gh up to ?is "t x has /eadily become m & m %>ply s]p5t9e4 ,aft] ! cut-(f has occurr$1 ! old *annel may = a "t cont9ue to be us$ by ! /ream 9 common ) ! new "o1 b ! advantage 9 velocity ( curr5t be+ ) ! cut-(f1 ! old *annel conta9s slack] wat] & s beg9s to fill ) silt bo? at ! beg9n+ & ! end ( ! loop4 ,ev5tually clos$ up at bo? ends1 ?is loop or 8ox-b[0 is entirely sep>at$ f ! new *annel1 & once ab&on$ ( ! /ream is trans=m$ into an ox-b[ lake 7,fig4 #aga & p4 #dae74 ,illu/ration3 ,,fig4 #aga4--;,an ox-b[ lake 9 ! flood pla9 ( a riv]4 ,me&] sc>s4--,sw++ z x occasionally does 9 its me&]+s q across ! flood pla9 & aga9/ ! bank ( ! e>li] degrad+ riv] 9 ?is section1 ! me&] at times sc\rs ! high bank :i* b\nds ! flood pla91 & und]m9+ x 9 ! same mann]1 x excavates a recess ( amphi!atral =m :i* is kn[n z a me&] sc> 7,fig4 #agb74 ,at l5g? ! entire bank is sc>r$ 9 ?is mann] s z to pres5t to ! /ream a s]ies ( concave scallops sep>at$ by %>p int]m$iate sali5ts ( cuspate =m4 ,illu/ration3 ,,fig4 #agb4--,s*ematic repres5tation ( a s]ies ( riv] t]races4 a1 b1 c1 e1 successive t]races 9 ord] ( age4 d1 d1 d1 d1 t]race slopes =m$ ( me&] sc>s4 ,riv] t]races4--,:5ev] ! riv]'s hi/ory is int]rupt$ by a small uplift1 or ! base level is = any reason l[]$1 ! /ream at once beg9s to s9k its *annel into ! flood pla94 ,once m fl[+ ^u a l[ grade1 x aga9 me&]s1 & s produces new walls at a l[] level1 b =m$1 l ! fir/1 ( int]sect+ me&] sc>s4 ,?us !re is produc$ a new flood pla9 ) cliff & t]race above1 :i* is kn[n z a riv] t]race4 ,a succession ( uplifts or ( depressions ( ! base level yields t]races 9 s]ies1 z !y appe> s*ematically repres5t$ 9 ,fig4 #agb4 ,su* t]races are to be f\nd well develop$ ^u mo/ ( our l>g] riv]s to ! nor?w>d ( ! ,ohio & ,miss\ri4 ,! highe/ t]race is obvi\sly ! remnant ( ! e>lie/ flood pla91 z ! l[e/ repres5ts ! late/4 ,! delta ( ! riv]4--,z x approa*es its m\? ! riv] moves m & m sluggi%ly ov] ! flat grades1 & sw+s 9 broad] me&]s z x fl[s4 ,yet x /ill c>ries a quantity ( silt :i* is only laid d[n aft] its curr5t has be5 /opp$ on meet+ ! body ( /&+ wat] into :i* x dis*>ges4 ,if ?is be ! ocean1 ! sal9ity ( ! sea wat] greatly aids 9 a quick precipitation ( ! f9e/ mat]ial4 ,?is cl>ify+ effect ^u ! wat] ( ! dissolv$ salt may be /rik+ly illu/rat$ by tak+ two simil> j>s1 ! "o fill$ ) fre% & ! o!r ) salt wat]1 & /irr+ ! same quantity ( f9e clay into ea*4 ,! clay 9 ! salt wat] is deposit$ & ! wat] cle>$ long be=e ! murk9ess ( ! o!r has disappe>$4 ,by ! lay+ d[n ( ! residue ( its burd5 ( s$im5t :]e x meets ! sea1 ! riv] builds up va/ pla9s ( silt & clay :i* are kn[n z deltas & :i* (t5 =m l>ge local ext5sions ( ! cont95ts into ! sea4 ,:]eas 9 its upp] rea*es ! riv] ) its tribut>y /reams appe>s 9 ! plan l a tree & its bran*es1 9 ! delta region ! /ream1 by divid+ into div]g+ *annels call$ di/ribut>ies 7,fig4 #deh1 p4 #dbj71 completes ! resemblance to ! tree by add+ ! roots4 ,f ! div]g5ce ( ! di/ribut>ies ^u ! delta pla9 ! ,greek capital lett] is sugge/$ & has suppli$ ! "n = ^! deposits4 ,( great f]tility1 ! delta pla9s ( riv]s h become ! d5sely populat$ regions ( ! globe1 among :i* x is necess>y to m5tion only ! delta ( ! ,nile 9 ,egypt1 ^? ( ! ,ganges & ,brahmaputra 9 ,india1 & ^? ( ! ,hoang & ,yangtse riv]s 9 ,*9a4 ,! levee4--,:5 ! sn[s ?aw ^u ! m\nta9s at ! headwat]s ( l>ge riv]s1 fre%ets result & ! delta regions are flood$4 ,at su* times heavily *>g$ ) s$im5t1 a ?9 deposit ( f]tile soil is left ^u ! surface ( ! delta pla91 & 9 ,egypt p>ticul>ly ?is is dep5d$ ^u = ! annual enri*m5t ( ! cultivat$ fields4 ,?\gh at ?is "t ! wat]s spread broadly ov] ! pla91 ! curr5t /ill cont9ues to fl[ l>gely )9 ! normal *annel1 s t ! slack wat] ^u ei!r side becomes ! locus = ! ma9 deposit ( ! s$im5t4 ,!re is ?us built up on ei!r side ( ! *annel a ridge ( silt :i* is kn[n z a levee1 & ?is bank is /eadily increas$ 9 height f ye> to ye> 7,fig4 #deb74 ,to prev5t ! dang] ( floods ^u ! inhabit$ pla9s1 artificial levees are usually rais$ ^u ! natural ones1 & 9 a c\ntry l ,holl&1 su* levees 7dikes7 involve a l>ge exp5diture ( money & no small degree ( eng9e]+ skill & exp]i5ce to con/ruct4 ,s important to ! life ( ! nation is ! prop] managem5t ( its dikes1 t 9 ! pa/ hi/ory ( ,*9a ea* weak adm9i/ration has be5 m>k$ by ! developm5t ( graft 9 ?is important dep>tm5t & by floods :i* h de/roy$ ! lives ( hundr$s ( ?\s&s ( p4 ,illu/ration3 ,,fig4 #agc4--8;,bird-foot0 delta ( ! ,mississippi ,riv]4 ,:]ev] !re has be5 a m>k$ly rapid s9k+ ^u a delta region1 & depressions are common 9 delta t]ritory1 no d\bt z a result ( ! load+ d[n ( ! cru/1 ! riv] may pres5t ! p>adoxical condition ( fl[+ at a high] level ?an ! surr\nd+ c\ntry4 ,betwe5 ! levees ( neighbor+ di/ribut>ies !re are peculi> sauc]-%ap$ depressions ( ! c\ntry :i* easily become fill$ ) wat]4 ,at ! extremity ( ! delta ! levee may be ! only l& :i* %[s above ! ocean surface1 & s pres5t ! peculi> 8bird-foot0 outl9e :i* is *>act]i/ic ( ! extremity ( ! ,mississippi delta1 ?\gh o!r processes ?an ! m]e s9k+ ( ! deposits may contribute to ?is result 7,fig4 #agc74 ,! sections ( delta deposits4--,if n[ we leave ! plan ( ! delta to consid] ! section ( its deposits1 we f9d !m s *>act]i/ic z to be easily recogniz$4 ,consid]$ broadly1 ! delta advances seaw>d aft] ! mann] ( a railroad embankm5t :i* is be+ c>ri$ across a lake4 ,?\gh ! great] portion ( ! deposit is unload$ ^u a /eep slope at ! front1 a small] am\nt ( mat]ial is dropp$ along ! way1 & a lay] ( extremely f9e mat]ial settles 9 advance z ! wat] cle>s ( its f9ely susp5d$ p>ticles 7,fig4 #agd74 ,simultane\s deposits )9 a delta ?us comprise a ne>ly horizontal lay] ( co>s] mat]ials1 ! s-call$ top-set b$2 ! bulk ( ! deposit 9 a =w>d slop+ lay]1 ! s-call$ =e-set b$2 & a ?9 film ( clay :i* is ext5d$ f> 9 advance1 ! bottom-set b$ 7,fig4 #agd1 #b74 ,if at any po9t a v]tical section is made ?r\gh ! deposits1 b$s deposit$ 9 diff]5t p]iods are enc\nt]$2 ! olde/ at ! bottom 9 a horizontal position1 ! next y\ng] above !m & ) =w>d dip1 & ! y\nge/ & co>se/ ^u ! top 9 ne>ly horizontal position 7,fig4 #agd1 #c74 ,illu/ration3 ,,fig4 #agd4--;,diagrams to %[ ! nature ( delta deposits z exhibit$ 9 section4 ,x has be5 e/imat$ t ! surface ( ! ,unit$ ,/ates is n[ be+ p>$ d[n by erosion at ! av]age rate ( an in* 9 #gfj ye>s4 ,! d]iv$ mat]ial is be+ deposit$ 9 ! flood pla9 & delta regions ( its pr9cipal riv]s4 ,"s #eac million tons ( susp5d$ matt] is 9 ! ,unit$ ,/ates c>ri$ to tidewat] ea* ye>1 & ab\t half z mu* m goes out to sea z dissolv$ matt]4 ,if ?is mat]ial 7 remov$ f ! ,panama ,canal cutt+1 an #he-;foot sea-level canal w\ld be excavat$ 9 ab\t #gc days4 ,! ,mississippi ,riv] alone c>ries annually to ! sea #cdj million tons ( susp5d$ matt]1 or two ?irds ( ! entire am\nt remov$ f ! area ( ! ,unit$ ,/ates z a :ole4 ,x is ?us little wond] t great deltas h ext5d$ _! b\nd>ies s rapidly & t ! cru/ is s g5]ally s9k+ b5ea? ! load4 ,,*apt] ,,xiii ,,e>? ,,features ,,%ap$ ,,by ,,runn+ ,,wat] ,! newly incis$ upl& & its %>p sali5ts4--,! successive /ages ( incis+1 sculptur+1 & f9ally ( r$uc+ an uplift$ l& area1 are ea* ( !m possess$ ( di/9ctive *>act]s :i* are all to be read ei!r f ! map or 9 ! l9es ( ! l&scape4 ,^u ! newly uplift$ pla9 ! incis+ by ! "y riv]s is to be f\nd *iefly 9 ! neighborhood ( ! m>g9s4 ,9 ?is /age ! valleys are describ$ z ,v-%ap$ caons1 = ! valley wall meets ! upl& surface 9 %>p sali5ts 7plate #ab ,a71 & ! l9es ( ! l&scape are ?r\gh\t made up f /raight elem5ts4 ,?\gh ! l&scapes ( ?is /age pres5t ! gr&e/ sc5]y t is kn[n & may be cut out 9 massive proportions1 (t5 ) ru%+ riv] or placid lake to enhance ! effect ( crag & gorge1 !y lack ! s(tness & grace ( outl9e :i* belong only to ! matur] erosion /ages4 ,! gr& caon ( ! ,colorado pres5ts ! features *>act]i/ic ( ?is /age 9 ! gr&e/ & mo/ sublime ( all examples1 & ! ca/l$ ,rh9e is a gorge ( rugg$ beauty1 c>v$ out f ! newly elevat$ plateau ( we/]n ,prussia1 ?r\gh :i* ! wat] swirls 9 eddy+ rapids 7,fig4 #age74 ,illu/ration3 ,,fig4 #age4--;,gorge ( ! ,riv] ,rh9e ne> ,/4 ,go>s1 incis$ )9 an uplift$ pla9 :i* =ms ! hill tops4 ,! /age ( adolesc5ce4--,z ! upl& becomes m l>gely invad$ z a consequ5ce ( ! headw>d advance ( ! caons & _! s5d+ out ( tribut>y side caons1 ! %>p angles 9 :i* ! caon walls int]sect ! pla9 become gradually replac$ by well-r\nd$ %\ld]s4 ,?us ! l9es 9 ! l&scape ( ?is /age are a comb9ation ( ! /raight l9e ) a simple curve convex t[>d ! sky 7,fig4 #agf74 ,9 ?is /age l>ge sections ( ! orig9al plateau rema91 ?\gh cut into small areas by ! ext5sions ( ! tribut>y valleys4 ,illu/ration3 ,,fig4 #agf4--,v-%ap$ valley ) well-r\nd$ %\ld]s *>act]i/ic ( ! /age ( adolesc5ce4 ,allegh5y plateau 9 ,we/ ,virg9ia4 ,! maturely dissect$ upl&4--,cont9u$ ramifications by ! riv]s ev5tually divide ! entire upl& area into sep>at$ p>ts1 & ! r\nd+ ( ! %\ld]s ( valleys proce$s simultane\sly until ( ! orig9al upl& no easily recognizable comp>tm5ts are to be f\nd4 ,:]e be=e 7 flat hilltops are n[ ridges or wat]%$s1 ! well-kn[n divides4 ,! upl& is n[ said to be completely dissect$ or to h arriv$ at maturity4 ,! /reams are /ill vigor\s1 = !y make ! full desc5t f ! upl& level to base level1 & yet a critical turn+ po9t ( _! hi/ory has be5 rea*$1 & f n[ on !y are to %[ a /eady fall+ (f 9 effici5cy z sculptur+ ag5ts4 ,illu/ration3 ,,fig4 #agg4--,view ( a maturely dissect$ upl& f "o ( its hilltops1 ,klama? ,m\nta9s1 ,cali=nia 7aft] a photograph by ,fairbanks74 ,view$ f "o ( ! hilltops1 ! l&scape ( ?is /age be>s a m>k$ resemblance to a sea 9 :i* ! numb]less divides are ! cre/s ( bill[s1 & ^!1 z di/ance r$uces _! importance 9 ! l&scape1 fade away into ! ev5 l9e ( ! horizon 7,fig4 #agg74 ,! ,hog>?ian l9e ( beauty4--,s9ce ! y\?ful /age ( ! upl&1 :5 ! l9es ( its l&scape 7 /raight1 its "* rugg$1 & its riv]s wild & turbul5t1 !re has be5 effect$ a complete trans=mation4 ,! only /raight l9e to be se5 is ! di/ant horizon1 = ! l&scape is n[ mold$ 9 s(t5$ outl9es1 among :i* !re is a repeat$ recurr5ce ( ! l9e ( beauty made fam\s by ,hog>? 9 8 8,analysis ( ,beauty40 ,z well kn[n to all art /ud5ts1 ?is is a s9u\s l9e ( rev]s$ or d\ble curvature--a curve :i* passes ins5sibly at a po9t ( inflection f convex to concave 7,fig4 #agh74 ,! curve ( beauty is n[ f\nd 9 e section ( ! hills1 & x imp>ts to ! l&scape a gracefulness & a measure ( re/fulness z well1 :i* are n to be f\nd 9 ! l&scapes ( e>li] /ages 9 ! erosion cycle4 ,9 ! bottoms ( ! valleys also ! initial w9d+s ( ! riv]s )9 _! n>r[ flood pla9s add silv] beauty l9es :i* /& out prom95tly f ! m somb] backgr\nd ( ! hills4 ,illu/ration3 ,,fig4 #agh4--;,hog>?'s l9e ( beauty4 ,consid]$ f ! comm]cial viewpo9t1 ! mature upl& is "o ( ! lea/ adaptable z a habitation = highly civiliz$ man4 ,direct l9es ( communication run up hill & d[n dale 9 monoton\s alt]nation1 & almo/ ! only way ( c>ry+ a railroad ?r\gh ! region1 )\t an exp5diture = tre/les :i* w\ld be prohibitive1 is to foll[ ! tortu\s cre/ ( a ma9 divide or ! equally w9d+ b$ ( "o ( ! l>g] valleys4 ,illu/ration3 ,,fig4 #agi4--,view ( ! old l& ( ,new ,engl&1 ) ,m\nt ,monadnock ris+ 9 ! di/ance4 ,! f9al product ( riv] sculpture--! p5epla94--,:5 maturity has be5 rea*$ 9 ! hi/ory ( a riv]1 its en]gies are devot$ to a p>+ d[n ( ! valley slopes & cre/s s z to r$uce ! g5]al level4 ,f ?is "t on hill summits no long] fall into a common level--t ( ! orig9al upl&--= "s m\nt notably high] ?an o!rs1 & ) increas+ age su* diff]5ces become acc5tuat$4 ,!re is n[ also a l>g] aggradation ( ! valleys to =m ! level floors ( flood pla9s1 out ( :i* at l5g? ! n[ slight elevations rise ^u su* g5tle slopes t ! process ( l& sculpture approa*es its end4 ,gradually ! vigor ( ! /ream has fad$ away1 & c n[ only be r5ew$ ?r\gh a fre% uplift ( ! l&1 or1 :at w\ld am\nt to ! same ?+1 a depression ( ! base level4 ,upl& & riv] h rea*$ old age toge!r1 & ! approximation to a new pla9 b little elevat$ above base level is s m>k$ t ! "n p5epla9 is appli$ to x4 ,scatt]$ elevations1 :i* because ( "s favor+ circum/ance rise to great] heights above ! g5]al level ( ! p5epla91 are kn[n z monadnocks aft] ! type example ( ,m\nt ,monadnock 9 ,new ,hamp%ire 7,fig4 #agi74 ,illu/ration3 ,,fig4 #ahj4--;,comp>ison ( ! cross sections ( riv] valleys = ! diff]5t /ages ( ! erosion cycle4 ,! riv] cross sections ( successive /ages4--,to ! successive /ages ( a riv]'s life x has be5 common to c>ry ov] ! names f ! well-m>k$ p]iods ( a human life4 ,if neglect+ = ! mom5t ! g5]al aspect ( ! upl&1 we fix our att5tion ^u ! *>act]i/ic cross sections ( ! riv] valley1 we f9d t "h also !re are cle>ly m>k$ *>act]s to di/+ui% ea* /age ( ! riv]'s life 7,fig4 #ahj74 ,9 infancy ! /eep1 n>r[1 & %>p-angl$ caon is a *>act]i/ic2 ) y\? ! wid] ,v-=m has already develop$2 9 adolesc5ce ! angles ( ! caon are trans=m$ into well-r\nd$ %\ld]s1 & ! valley broad5s s z 9 ! l[] rea*es to lay d[n a flood pla92 9 maturity ! divides & ! d\ble curves ( ! l9e ( beauty appe>2 :ile 9 ! decl9e ( old age ! valleys are extremely broad & flat & are floor$ by an ext5d$ flood pla94 ,! entr5*m5t ( me&]s ) r5ew$ uplift4--,^u ! r$uc$ grades :i* are *>act]i/ic ( ! decl9+ /age ( a riv]'s life1 ! curr5t has little p[] to modify ! surface configuration4 ,on ! old l& ( ?is /age a r5ew$ uplift />ts ! /reams aga9 into action4 ,?is infusion ( driv+ p[] into mov+ wat]1 reg>d$ z a ma*9e capable ( accompli%+ c]ta9 "w1 is l w9d+ up a clock t has run d[n4 ,once m ! /reams acquire a velocity suffici5t to enable !m to cut _! valleys into ! l& surface1 & s a new erosional cycle may be inaugurat$ ^u ! old l& surface--! p5epla94 ,aft] su* an uplift has be5 accompli%$ & ! riv]s h sunk _! e>ly valleys )9 ! new upl&1 we may look out f ?is n[ elevat$ surface & ! eye take 9 b a s+le horizontal l9e1 s9ce we view ! pla9 along its edge4 ,illu/ration3 ,,fig4 #aha4--,! ,beav]tail ,b5d ( ! ,yakima ,caon 9 c5tral ,wa%+ton 7aft] ,george ,otis ,smi?74 ,by ! uplift ! me&]s ( ! e>li] riv]s may become entr5*$ 9 ! new upl&1 ! wide lobes ( ! individual me&]s be+ n[ sep>at$ by m\nta9s :]e be=e _h be5 pla9s ( silt only4 ,! ,new ,riv] ( ! ,cumb]l& plateau & ! ,yakima ,riv] ( c5tral ,wa%+ton 7,fig4 #aha7 furni% excell5t ,am]ican examples ( intr5*$ me&]s1 z ! ,moselle ,riv] does 9 ,europe4 ,^u ! c\rse ( ! latt] riv] ne> ! t[n ( ,zell a tunnel ( ! railroad a qu>t] ( a mile 9 l5g? pi]ces a m\nta9 9 ! neck ( a me&] lobe 9 :i* ! riv] itself travels a di/ance ( m ?an six miles 9 ord] to make ! same advance4 ,! ,kais] ,wilhelm tunnel 9 ! same di/rict p5etrates a l>g] m\nta9 includ$ 9 a d\ble me&] ( ! riv]4 ,al?\gh intr5*$1 riv] me&]s are /ill compet5t to sc\r & s und]m9e ! out] bank1 & ) favor+ conditions !y may by ?is process erode ext5d$ 8bottoms0 out ( ! plateau4 7,see ,lockport quadrangle1 ,u4 ,s4 ,g4 ,s47 ,! valley ( ! rejuv5at$ riv]4--,:5ev] a new uplift occurs be=e an erosional cycle has be5 complet$1 ! riv]s become intr5*$1 n 9 a p5epla91 b 9 ! bottoms ( broad valleys4 ,! sweep+ curves :i* *>act]ize mature l&scapes may ?us be br\ght into /rik+ contra/ ) ! /raight l9es ( y\?ful caons :i* ) ,v-sections desc5d f _! l[e/ levels 7,fig4 #ahb74 ,! full cross section ( su* a valley %[s a c5tral ,v ^: %>p %\ld]s are ext5d$ outw>d & upw>d 9 ! s(t5$ curves ( lat] erosion /ages4 ,illu/ration3 ,,fig4 #ahb4--;,a rejuv5at$ riv] valley 7aft] a photograph by ,fairbanks74 ,! arre/ ( /ream erosion by ! m resi/ant rocks4--,! capacity ( a riv] to erode & c>ry away ! rock mat]ial t lies along its c\rse is dep5d5t n only ^u ! velocity ( ! curr5t1 b also ^u ! h>dness1 ! firmness ( texture1 & ! solubility ( ! mat]ial4 ,p>ticul>ly 9 arid & semi>id regions1 :]e no mantle ( vegetation is at h& to mask ! surfaces ( ! firm] rock masses1 diff]5ces ( ?is k9d are /amp$ deeply ^u ! l&scape4 ,! rock t]races 9 ! ,gr& ,caon ( ! ,colorado toge!r repres5t ! /rong] rock =mations ( ! region1 :ile slop+ talus accumulations bury ! weak] b$s f sight4 ,illu/ration3 ,,fig4 #ahc4--,plan ( a riv] n>r[s4 ,ea* area ( h>d] rock :i* rises a?w>t ! c\rse ( a /ream causes a tempor>y arre/ 9 ! process ( valley erosion & is responsible = a notewor?y local contraction ( ! riv] valley4 ,! valley is c>v$ less widely z well z less deeply1 & s9ce a riv] c nev] corrade bel[ its base1 a 8tempor>y base level0 is = a "t e/abli%$ above ! area ( h>d] rock4 ,ow+ to ! contraction ( ! valley "u ^! conditions1 ! locality is describ$ z a riv] n>r[s 7,fig4 #ahc74 ,! n>r[s ^u ! ,hudson ,riv] occur 9 ! ,highl&s :]e ! riv] leaves a broad expanse occupi$ by s(t] s$im5ts to trav]se an isl&-l area ( h>d cry/all9e rocks4 ,)9 ! n>r[s ( a riv] ! /eep walls1 *>act]i/ic ( y\? & ! turbul5t curr5t z well1 are (t5 reta9$ long aft] o!r portions ( ! riv] h acquir$ ! m re/ful l9es ( riv] maturity4 ,! picturesque crag & ! g5]ally rugg$ "* ( riv] n>r[s r5d] !m po9ts ( special int]e/ ^u e navigable riv]4 ,illu/ration3 ,,fig4 #ahd4--,successive diagrams to illu/rate repeat$ riv] piracy & ! developm5t ( 8trellis dra9age01 7aft] ,russell74 ,! capture ( "o riv]'s t]ritory by ano!r4--,! effect ( a h>d lay] ( rock int]pos$ 9 ! c\rse ( a /ream is ?us always to delay ! advance ( ! erosional process at all levels above ! ob/ruction4 ,:5 a /ream 9 incis+ its valley degrades its *annel ?r\gh a v5e] ( s(t] rocks into h>d] mat]ials bel[1 x is te*nically describ$ z hav+ discov]$ ! h>d] lay]4 ,:]e sev]al neighbor+ /reams fl[ by simil> r\tes to _! common base level1 ^? :i* discov] a h>d] rock w advance _! headwat]s less rapidly into ! upl& & s w be at a disadvantage 9 ext5d+ _! dra9age t]ritory4 ,a /ream :i* is n ?us h9d]$ w 9 ! c\rse ( "t rob ! o!rs ( a portion ( _! t]ritory1 = x is able to erode its l[] rea*es ne>] to base level & ?us acquire = its upp] rea*es1 :]e erosion is *iefly accompli%$1 an advantage 9 declivity4 ,! divide :i* sep>ates its headwat]s f ^? ( its less favor$ neighbor w 9 consequ5ce migrate /eadily into ! neighbor's t]ritory4 ,! divide is ?us a sort ( b\nd>y wall sep>at+ ! dra9age bas9s ( neighbor+ /reams1 & any migration mu/ ext5d ! t]ritory ( ! "o at ! exp5se ( ! o!r4 ,z m & m t]ritory is br\ght "u ! dom9ion ( ! m favor$ /ream1 !re w come a "t :5 ! divide 9 its migration w arrive at ! *annel ( ! /ream t is be+ robb$1 & s by a sudd5 act ( annexation draw (f all ! upp] wat]s into its own bas94 ,by ?is capture ! /ream ^: t]ritory has be5 invad$ is said to h be5 behead$4 ,by ?is act ( piracy ! /rong] /ream n[ develops exceptional activity because ( ! local /eep grades ne> ! po9t ( capture1 & ) ?is newly acquir$ cutt+ p[] ! invad] is compet5t to advance /ill fur!r & ent] ! t]ritory ( ! /ream t lies next beyond4 ,! type ( dra9age network :i* results f repeat$ captures ( ?is k9d is kn[n z 8trellis dra9age0 7,fig4 #ahd71 a type well illu/rat$ by ! riv]s ( ! s\!rn ,appala*ians4 ,9 g5]al x may be said t1 o!r conditions be+ ! same1 ( two neighbor+ /reams :i* h a common base level1 t "o :i* takes ! longe/ r\te w lose t]ritory to ! o!r1 s9ce x mu/ h ! flatt] av]age slope4 ,/ream capture may ?us come ab\t )\t ! discov]y ( h>d rock lay]s :i* are m unfavorable to "o /ream ?an ano!r4 ,illu/ration3 ,,fig4 #ahe4--,sket* maps to %[ ! e>li] & ! pres5t dra9age condition ab\t ! ,blue ,ridge ne> ,h>p]'s ,f]ry4 ,wat] & w9d gaps4--,9 ! ,allegh5y plateau riv]s cross1 ! range ( h>d] rocks 9 deep m\nta9 n>r[s :i* ^u ! horizon appe> z gateways ?r\gh ! b>ri] ( ! m\nta9 wall4 ,su* gateways are sometimes ref]r$ to z 8wat] gaps01 ( :i* ! ,delaw>e ,wat] ,gap is p]haps ! be/ kn[n example1 ?\gh ! ,potomac crosses ! ,blue ,ridge at ! hi/oric ,h>p]'s ,f]ry ?r\gh a simil> portal4 ,! valley ( ! tribut>y ,%5&oah has be5 ! sc5e ( an int]e/+ episode 9 ! /ruggle ( rival /reams :i* is typical ( o!rs 9 ! same upl& region4 ,! records :i* may be made out f ! l&scapes %[ cle>ly t 9 an e>li] b rec5t p]iod1 :5 ! g5]al surface /ood at a high] level :i* has be5 call$ ! ,kittat9ny ,pla91 ! y\ng] ,potomac ( t "t & a y\ng] b l>g] ance/or ( ,beav]dam ,creek ea* cross$ ! ,blue ,ridge ( ! "t ?r\gh simil> wat] gaps 7,fig4 #ahe1 map1 & ,fig4 #ahf74 ,! ,potomac ( t "t 01 h[ev]1 ! m deeply intr5*$1 & possess+ an advantage 9 slope x 0 able to advance ! divide at ! head ( its tribut>y1 ! ,%5&oah1 into ! t]ritory ( ,beav]dam ,creek4 ,?us ! behead+ ( ! ,beav]dam by ! ,%5&oah 0 accompli%$ 7,fig4 #ahe1 second map7 & its upp] wat]s annex$ to ! ,potomac sy/em4 ,) ! subsequ5t l[]+ ( ! g5]al level ( ! c\ntry :i* yield$ ! pres5t ,%5&oah ,pla91 ! =m] wat] gap ( ,beav]dam ,creek 0 ab&on$ ( its /ream at a high level 9 ! range4 ,kn[n z ,snick]s ,gap1 x may s]ve z a type ( ! 8w9d gaps0 ( simil> orig9 :i* are n altoge!r uncommon 9 ! ,appala*ian ,m\nta9 sy/em 7,fig4 #ahf74 ,illu/ration3 ,,fig4 #ahf4--,section to illu/rate ! hi/ory ( ,snick]s ,gap4 ,"* pr(iles4--,= humid regions ! l&scapes possess *>act]s :i*1 speak+ broadly1 dep5d ^u ! /age ( ! erosion cycle4 ,= ! e>lie/ /ages ! /raight l9e ent]s z almo/ ! only elem5t 9 ! design2 z ! cycle advances to adolesc5ce ! r\nd$ =ms beg9 to replace ! angles ( ! immature /ages1 & ) full maturity ! l9es ( beauty alone are *>act]i/ic4 ,z ?is critical /age is pass$ irregul>ity ( feature & ev] m flatt5$ curves are f\nd to correspond to ! decl9e ( ! riv]'s vital en]gies4 ,!re are ?us m>ks ( s5ility 9 ! "w ( riv]s 7,fig4 #ahg74 ,illu/ration3 ,,fig4 #ahg4--;,"* pr(iles ( l&scapes %ap$ by /ream erosion 9 humid climates4 ,,read+ ,,ref]5ces ,,= ,,*apt]s ,,xii ,,& ,,xiii ,g5]al3-- ,,sir ,,john ,,playfair4 ,illu/rations ( ! ,huttonian ,!ory ( ! ,e>?4 ,ed9burgh1 #ahjb1 pp4 #cej-cga4 ,j4 ,w4 ,,p[ell4 ,exploration ( ! ,colorado ,riv] ( ! ,we/ & its ,tribut>ies4 ,wa%+ton1 #ahge1 pp4 #adi-bad4 ,g4 ,k4 ,,gilb]t4 ,report on ! ,geology ( ! ,h5ry ,m\nta9s4 ,wa%+ton1 #ahgg1 pp4 #ii-aej4 7,a classic ^u ! "w ( riv]s47 ,c4 ,e4 ,,dutton4 ,t]ti>y ,hi/ory ( ! ,gr& ,caon ,di/rict 7) atlas71 ,mon4 #b1 ,u4 ,s4 ,geol4 ,surv41 #ahhb1 pp4 #bfd4 ,w4 ,m4 ,,davis4 ,! ,riv]s & ,valleys ( ,p5nsylvania1 ,nat4 ,geogr4 ,mag4 vol4 #a1 #ahhi1 pp4 #bjc-bai2 ,! ,triassic ,=mation ( ,connecticut1 #ah? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ii1 #ahih1 pp4 #add-aec4 ,,sir ,a4 ,,geikie4 ,! ,sc5]y ( ,scotl&4 ,london1 #aija1 pp4 #a-ab4 ,i4 ,c4 ,,russell4 ,riv]s ( ,nor? ,am]ica4 ,putnam4 ,new ,york1 #ahih1 pp4 #cbg4 ,m4 ,r4 ,,campbell4 ,dra9age ,modifications & _! ,int]pretation1 ,j\r4 ,geol41 vol4 #d1 #ahif1 pp4 #efg-eha1 #feg-fgh4 ,,h5ry ,,gannett4 ,physiographic ,types1 ,u4 ,s4 ,geol4 ,surv41 ,topographic ,atlas1 ,folios #a-b1 #ahif1 #aijj4 ,w4 ,m4 ,,davis4 ,! ,geographical ,cycle1 ,geogr4 ,j\r41 vol4 #ad1 #ahii1 pp4 #dha-ejd4 ,! flood pla93-- ,,h5ry ,,gannett4 ,! ,flood ( ,april1 #ahig1 9 ! ,l[] ,mississippi1 ,scot4 ,geogr4 ,mag41 vol4 #ac1 #ahig1 pp4 #dai-dba4 ,w4 ,m4 ,,davis4 ,! ,developm5t ( ,riv] ,me&]s1 ,geol4 ,mag41 ,decade iv1 vol4 #aj1 #aijc1 pp4 #ade-adh4 ,w4 ,s4 ,,t[]4 ,! ,developm5t ( ,cut-(f ,me&]s1 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #cf1 #aijd1 pp4 #ehi-eii4 ,riv] t]races3-- ,w4 ,m4 ,,davis4 ,! ,t]races ( ! ,we/field ,riv]1 ,massa*usetts1 ,am4 ,j\r4 ,sci41 vol4 #ad1 #aijb1 pp4 #gg-id1 pl4 #d2 ,riv] ,t]races 9 ,new ,engl&1 ,bull4 ,mus4 ,comp4 ,zol41 vol4 #ch1 #aijb1 pp4 #bha-cdf4 ,riv] deltas3-- ,g4 ,k4 ,,gilb]t4 ,! ,topographic ,features ( ,lake ,%ores1 #e? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #ajd-ajh2 ,lake ,bonneville1 ,mon4 ,i1 ,u4 ,s4 ,geol4 ,surv41 #ahij1 pp4 #aec-afg4 ,*>ts ( ,mississippi ,riv] ,commission4 ,g4 ,r4 ,,cr$n]4 ,die ,deltas1 ihre ,morphologie1 geographis*e ,v]breitung und ,ent/ehungsb$+ung51 ,pet4 ,mitt4 ,ergh4 #ef1 #ahgh1 pp4 #a-gd1 pls4 #a-c4 ,! p5epla93-- ,w4 ,m4 ,,davis4 ,pla9s ( ,m>9e & ,subarial ,d5udation1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #g1 #ahif1 pp4 #cgg-cih2 ,! ,p5epla91 ,am4 ,geol41 vol4 #bc1 #ahii1 pp4 #bjg-bci4 ,intr5*m5t ( me&]s3-- ,w4 ,m4 ,,davis4 ,! ,se9e1 ! ,meuse1 & ! ,moselle1 ,nat4 ,geogr4 ,mag41 vol4 #g1 #ahif1 pp4 #ahi-bjb4 ,/ream capture3-- ,n4 ,h4 ,,d>ton4 ,examples ( ,/ream ,robb+ 9 ! ,catskill ,m\nta9s1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #g1 #ahif1 pp4 #eje-ejg1 pl4 #bc4 ,,colli] ,,cobb4 ,a ,recapture f a ,riv] ,pirate1 ,sci5ce1 vol4 #bb1 #ahic1 p4 #aie4 ,,william ,h4 ,,hobbs4 ,! ,/ill ,riv]s ( ,we/]n ,connecticut1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ac1 #aijb1 pp4 #ag-bb1 pl4 #a4 ,,isaiah ,,b[man4 ,a ,typical ,case ( ,/ream ,capture 9 ,mi*igan1 ,j\r4 ,geol41 vol4 #ab1 #aijd1 pp4 #cbf-ccd4 ,,*apt] ,,xiv ,,! ,,travels ,,( ,,! ,,und]gr\nd ,,wat] ,! desc5t )9 ! unsaturat$ zone4--,( ! moi/ure precipitat$ f ! atmosph]e1 t portion :i* nei!r evaporates into ! air nor runs (f ^u ! surface1 s9ks into ! gr\nd & is describ$ z ! gr\nd wat]4 ,"h x desc5ds by gravity ?r\gh ! pores & op5 spaces1 & at a q mod]ate dep? arrives at a zone :i* is completely saturat$ ) wat]4 ,! dep? ( ! upp] surface ( ?is saturat$ zone v>ies ) ! humidity ( ! climate1 ) ! altitude ( ! e>?'s surface1 & ) _m o!r simil>ly v>y+ factors4 ,)9 humid regions its dep? may v>y f a few feet to a few hundr$ feet1 :ile 9 des]t areas ! surface may lie z l[ z a ?\s& feet or m4 ,! surface ( ! zone ( ! li?osph]e t is saturat$ ) wat] is call$ ! wat] table1 & ?\gh less acc5tuat$ x con=ms 9 g5]al to ! relief ( ! c\ntry 7,fig4 #ahh74 ,its dep? at any po9t is f\nd f ! levels ( all p]5nial /reams & f ! levels at :i* wat] /&s 9 wells4 ,illu/ration3 ,,fig4 #ahh4--;,diagram to %[ ! seasonal range 9 ! position ( ! wat] table & ! cause ( int]mitt5t /reams4 ,dur+ ! season ( small precipitation ! wat] table is l[]$1 & if at su* times x falls bel[ ! b$ ( a valley1 ! surface /ream )9 ! valley dries up1 to be reviv$ :51 aft] heavi] precipitation1 ! wat] table has 9 turn be5 rais$4 ,su* /reams are said to be int]mitt5t1 & are especially *>act]i/ic ( semi>id regions 7,fig4 #ahh74 ,:]ev] 9 desc5d+ f ! surface an imp]vi\s lay]1 su* z clay1 is enc\nt]$1 ! fur!r d[nw>d progress ( ! wat] is arre/$4 ,n[ conduct$ 9 a lat]al direction x issues at ! surface z a spr+ at ! l9e ( em]g5ce ( ! upp] surface ( ! imp]vi\s lay] 7,fig4 #ahi74 ,illu/ration3 ,,fig4 #ahi4--;,diagram to %[ h[ an imp]vi\s lay] conducts ! desc5d+ wat] 9 a lat]al direction to issue 9 surface spr+s4 ,! trunk *annels ( desc5d+ wat]4--,:ile )9 ! unconsolidat$ rock mat]ials ne> ! surface ( ! e>?1 x is cle> t wat] c circulate 9 proportion z ! mat]ials are por\s & s relatively p]vi\s4 ,z ! pore spaces become m9ute & capill>y1 ! difficulty ( p]meation ?r\gh ! mat]ials becomes v great4 ,?us 9 ! noncoh]5t rocks x is ! co>se gravel & ! lay]s ( s& :i* s]ve z ! und]gr\nd *annels1 :ile ! f9e clays h ! effect ( an imp]vi\s wall ^u ! circulat+ wat]s4 ,9 co>se s& z mu* z a ?ird ( ! volume ( ! mat]ial is pore space = ! absorption & transmission ( wat]4 ,ev5 "u ^! favorable conditions ! movem5t ( ! wat] is exce$+ly sl[ & usually less ?an a fif? ( a mile a ye>4 ,illu/ration3 ,,fig4 #aij4--,sket* map ( ! ,oucane de ,*abrires ne> ,*orges 9 ! ,high ,alps1 to illu/rate ! corrosion ( lime/one along two s]ies ( v]tical jo9ts 7aft] ,m>tel74 ,)9 ! h>d rocks x is ! s&/ones :i* h ! l>ge/ pore spaces1 b 9 ne>ly all consolidat$ rocks !re are additional spaces along c]ta9 ( ! b$d+ planes1 ! jo9t op5+s 7,fig4 #aij71 & ! cru%$ zones ( displacem5t1 s t ^! p>t+ planes become ! trunk *annels1 s to speak1 ( ! circulat+ wat]4 ,x is along su* crevices t 9 ! c\rse ( "t ! m9]al matt] c>ri$ 9 solution by ! wat] is deposit$ to produce ! ore ve9s & ! associat$ cry/alliz$ m9]als4 ,! cav]ns ( lime/ones4--,:]e lime/one =mations h a ne>ly flat upp] surface1 a l>ge "p ( ! surface wat] ent]s ! rock by way ( ! jo9t spaces1 :i* x soon wid5s by solution into broad crevices ) well-r\nd$ %\ld]s4 ,at jo9t int]sections solution ( ! lime/one is s favor$ t ! wat] may "h desc5d 9 a sort ( v]tical %aft until x meets a b$d+ plane ext5d+ lat]ally & (f]+ m favorable conditions = corrosion4 ,its j\rney n[ beg9s 9 a lat]al direction1 & solution ( ! rock cont9u+1 a tunnel may be et*$ out & ext5d$ until ano!r jo9t is enc\nt]$ :i* is favorable to its fur!r desc5t into ! =mation4 ,by ?is process on alt]nat+ %afts & gall]ies ! wat] desc5ds to ne> ! surface ( ! wat] table by a s]ies ( /eps1 & is ev5tually dis*>g$ into ! riv] sy/em ( ! di/rict 7,fig4 #aia74 ,)9 ! l>g] cav]ns ! wat] at ! l[e/ level usually fl[s z a subt]ranean riv] to em]ge lat] into ! light f b5ea? a rock ar*4 ,illu/ration3 ,,fig4 #aia4--;,diagram to %[ ! relation ( cav]ns 9 lime/one to ! riv] sy/em ( ! di/rict & to ! 8swall[ holes0 ^u ! surface4 ,f ! plan ( a sy/em ( connect+ cav]ns x may (t5 be obs]v$ t ! gall]ies ( ! sev]al levels are alike direct$ along two rectangul> directions :i* indicate ! ma/] jo9t directions )9 ! lime/one =mation4 ,?is is especially cle> f ! map ( ! gall]ies 9 ! explor$ portions ( ! ,mammo? ,cave 7,fig4 #aib74 ,swall[ holes & lime/one s9ks4--,above ! cav]ns ( lime/one =mations !re are select$ po9ts :]e ! wat] has desc5d$ 9 ! l>ge/ volume1 & "h funnel-%ap$ depressions h be5 dissolv$ out f ! surface ( ! rock4 ,9 diff]5t di/ricts su* depressions h become kn[n z 8s9ks01 8swall[ holes01 entonnoirs1 & ,orgeln4 ,:]ev] ! depressions h a *>act]i/ic circul> outl9e1 !re c be little d\bt t !y are ! product ( solution by ! desc5d+ wat]1 & h relatively small connections only ) ! subt]ranean cav]ns4 ,!y h ?us naturally collect$ ^u _! bottoms ! insoluble clay :i* 0 conta9$ 9 ! impure lime/one z well z a c]ta9 am\nt ( slope wa% f ! surface4 ,inasmu* z ! clays are imp]vi\s to wat]1 ! bottoms ( ^! swall[ holes are bett] suppli$ ) moi/ure ?an ! surr\nd+ rock surfaces1 & by n\ri%+ a m vigor\s plant gr[? are /rongly impress$ ^u ! l&scape 7,fig4 #aic74 ,illu/ration3 ,,fig4 #aib4--,plan ( a portion ( ,mammo? ,cave1 ,k5tucky 7aft] ,h4 ,c4 ,hovey74 ,illu/ration3 ,,fig4 #aic4--,trees & %rubs gr[+ luxuriantly ^u ! bottoms ( s9ks )9 a lime/one c\ntry 7aft] a photograph by ,h4 ,t4 ,a4 de ,l4 ,hus74 ,c]ta9 ( ! depressions above cav]ns are1 h[ev]1 less regul> 9 outl9e1 & _! bottoms are occupi$ by a mass ( lime/one rubble4 ,9 "s in/ances1 at lea/1 ^! depressions appe> to be ! result ( local incav+ ( ! cav]n ro(s4 ,an incav+ ( ?is nature may close up an e>li] gall]y 9 ! cav]n & div]t ! cave wat]s to a new c\rse4 ,! de/ruction ( ! ro(s ( cav]ns ?r\gh ?is process ( incav+ may cont9ue until only relatively small remnants are left4 ,f long subt]ranean tunnels ! caves are ?us trans=m$ into subarial rock bridges t h become kn[n z 8natural bridges40 ,! be/-kn[n ,am]ican example is ! ,natural ,bridge ne> ,lex+ton1 ,virg9ia4 ,mu* gr&] natural bridges h be5 =m$ 9 s&/one by a totally diff]5t process1 & mu/ n be confus$ ) ^! lime/one remnants ( cav]ns4 ,! s9t] deposits4--,j z wat] c dissolve ! calc>e\s rocks ) ! =mation ( cav]ns1 x c "u o!r conditions deposit ! mat]ial :i* has ?us be5 tak5 into solution4 ,its p[] to hold c>bonate ( lime 9 solution is dep5d5t ^u ! pres5ce ( c>bonic acid gas )9 ! wat]4 ,wat] *>g$ ) gas & dissolv$ lime c>bonate is said to be 8h>d01 & if ! gas be driv5 (f by boil+ or o!rwise1 ! dissolv$ lime is ?r[n out ( solution & deposit$ 9 a =m well kn[n to all h\sekeep]s4 ,h>d wat] fl[+ 9 a surface /ream1 if da%$ into spray at a cascade1 may deposit its lime c>bonate 9 an ev] ?ick5+ v5e] :]ev] ! spray is da%$ ab\t ! falls4 ,?is mat]ial1 :5 cut 9 section1 has wav+ p>allel lay]s & is kn[n z trav]t9e or calc>e\s s9t]4 ,"s ( ! mo/ rem>kable deposits ( ?is nature may be se5 at ! cascade ( ,tivoli ne> ,rome1 & mo/ ( ! ,roman build+s h be5 con/ruct$ f trav]t9e t has be5 qu>ri$ 9 ! vic9ity4 ,! gr[? ( /alactites4--,wat]1 aft] p]colat+ sl[ly ?r\gh ! crevices ( lime/one1 :]e x becomes *>g$ ) ! c>bonic acid gas & ) dissolv$ c>bonate ( lime1 may trickle f ! ro( ( a cav]n4 ,em]g+ f ! n>r[ crevice1 x may give (f "s ( its conta9$ gas & is usually subject to evaporation1 ) ! result t ! lime c>bonate is left adh]+ to ! rock surface f :i* evaporation took place4 ,if ! wat] collects ^u ! cav]n ro( s sl[ly t x c entirely evaporate be=e a drop c =m1 ! entire cont5t ( c>bonate w be left adh]+ to ! ro(4 ,evaporation is mo/ rapid ne> ! m>g9s & ov] ! c5t] ( ea* drop z x develops1 & ! deposit :i* is left ?us takes ! =m ( t9y :ite r+s at ^? po9ts ^u ! crevice :]e !re is ! easie/ passage = ! trickl+ wat]4 ,to ! out] surface ( ^! r+s wat] w fir/ adh]e & !n evaporate1 z x w also sl[ly ooze ?r\gh ! passage 9 ! r+1 b "h )\t evaporation until x rea*es ! l[] surface4 ,a p5dant /ructure w1 !re=e1 develop1 gr[+ outw>d 9 all directions by ! deposition ( conc5tric lay]s :i* are ?icke/ ne> ! ro(1 & d[nw>d into ! =m ( a rock 8icicle0 ?r\gh evaporation ( ! wat] :i* collects ne> ! tip4 ,^! p5dant s9t] =mations are kn[n z /alactites & are ?us =m$ ( conc5tric lay]s arrang$ l a s]ies ( ne/$ cornucopias ) a p]=ation ( ne>ly uni=m calib] along ! axis ( ! /ructure 7,fig4 #aid74 ,illu/ration3 ,,fig4 #aid4--;,diagrams to %[ ! mann] ( =mation ( /alactites1 /alagmites1 & s9t] columns b5ea? p>allel crevices ^u ! ro(s ( cav]ns 79 "p aft] von ,knebel74 ,=mation ( /alagmites4--,:]ev] ! wat] p]colates ?r\gh ! ro( ( ! cav]n s rapidly t x _c entirely evaporate ^u ! ro(1 a portion falls to ! floor1 &1 spatt]+ z x /rikes1 builds up a relatively ?ick cone ( s9t] kn[n z a /alagmite1 & ?is is accurately c5t]$ b5ea? a /alactite ^u ! ro(4 ,9 proportion z ! cav]n is high1 ! dropp+ wat] is widely disp]s$ z x /rikes ! floor1 ) ! =mation ( a correspond+ly ?ick & blunt /alagmite4 ,z ?is rises by gr[? t[>d ! ro(1 x (t5 develops ^u its summit a di/9ct crat]-l depression 7,fig4 #aid1 l[] figure74 ,:5 ! process is long cont9u$1 /alactites & /alagmites may gr[ toge!r to =m columns :i* may be rang$ ) _! neighbors l ! pipes ( an organ1 & l !m !y give out cle> tones :5 /ruck lightly ) a mallet4 ,at o!r times ! columns are jo9$ to _! neighbors to =m hang+s & drap]ies ( ! mo/ fanta/ic & beautiful design 7,fig4 #aie74 ,illu/ration3 ,,fig4 #aie4--,s9t] =mations 9 ! ,luray cav]ns1 ,virg9ia4 ,9 remote antiquity lime/one cav]ns af=d$ a refuge to _m species ( pr$atory birds & animals z well z to our e>lie/ ance/ors4 ,! bones ( all ^! d5iz5s ( ! caves lie entomb$ )9 ! clays & ! s9t] =mations ^u ! cav]n floors1 & !y tell ! /ory ( a fi]ce & long-cont9u$ w>f>e = ! possession ( ^! natural /rongholds4 ,! evid5ce is cle> t ^! cave m5 ) _! primitive weapons 7 able at times to drive away ! cave be>s1 lions1 & hy5as1 & to set up 9 ! cav]n _! simple he>?s1 only 9 _! turn to be conqu]$ by ! f]ocity ( _! enemies4 ,"s ( ! ,european caves h yield$ _m wagonloads ( ! skeletons ( ^! fi]ce pr$atory animals1 toge!r ) ! simple weapons ( ! primitive man4 ,! ,k>/ & its features4--,mo/ s-call$ lime/ones h a l>ge admixture ( argillace\s mat]ials 7clays7 & ( silice\s or s&y p>ticles4 ,su* impurities make up ! bulk ( ! clays & muds :i* are left beh9d :5 ! soluble portions ( ! lime/one h be5 dissolv$4 ,illu/ration3 ,,fig4 #aif4--,map ( ! dol9es ( ! ,k>/ region ne> ,divaa4 ,swall[ holes we h f\nd to be *>act]i/ic features )9 su* di/ricts4 ,:5 lime/ones are m ne>ly pure1 z 9 ! ,k>/ region ea/ ( ! ,adriatic ,sea1 simil> features are develop$1 b ^u a gr&] scale1 & c]ta9 additional =ms are enc\nt]$4 ,9 place ( ! s9k or swall[ hole1 !re appe>s ! 8k>/ funnel0 or dol9e1 a deep1 b[l-%ap$ depression hav+ a flat bottom4 ,su* funnels may be #cj to #cjjj feet across & f #f to #cjj feet 9 dep? 7,fig4 #aif74 ,?\gh 9 "o or two in/ances kn[n to be ! result ( ! break d[n ( cav]n ro(s 7,fig4 #aig71 yet l ! swall[ holes ( o!r regions ^! l>g] funnels appe> g5]ally to be ! "w ( solution by ! desc5d+ wat]s4 ,:]e !y h be5 op5$ 9 artificial cutt+s along railroads or 9 m9es1 ! orig9al rock is f\nd intact at ! bottom1 ) small crevices only go+ d[n to l[] levels4 ,ov] ! bottoms ( ! dol9es !re is spread a lay] ( f]tile r$ clay1 ! t]ra rossa1 l t :i* is obta9$ z a residue :5 a fragm5t ( ! lime/one has be5 dissolv$ 9 laboratory exp]im5ts4 ,illu/ration3 ,,fig4 #aig4--;,cross section ( ! dol9e =m$ by inbreak ( a cav]n ro(4 ,! ,/>a ,apn5ka dol9e 9 ,c>9?ia 7aft] ,m>tel74 ,a des]t f ! de/ruction ( =e/s4--,betwe5 ! dol9es is f\nd a v]itable des]t ) jutt+ lime/one angles & little if any vegetation4 ,! wat] :i* falls ^u ! surface ei!r runs (f quickly or goes d[n to ! subt]ranean cav]ns by :i* s mu* ( ! c\ntry is und]m9$4 ,h5ce x is t ! g>d5s :i* furni% ! su/5ance = ! scatt]$ population are all includ$ )9 ! n>r[ limits ( ! dol9e bottoms4 ,al?\gh to-day s l>gely a b>r5 wa/e1 we "k t ! ,k>/ ^u ! ,adriatic 0 9 remote antiquity a heavily =e/$ region & t x suppli$ ! myriads ( wood5 piles ^u :i* ! city ( ,v5ice is support$4 ,! vessels :i* br\ght to ?is port ^u ! ,adriatic its anci5t prosp]ity 7 built f wood br\ght f ?is tract ( mod]n des]t4 ,9 ! days ( ,v5etian gr&eur ! f]tile t]ra rossa =m$ a v5e] ^u ! rock surface ( ! ,k>/ & s reta9$ ! surface wat]s = ! support ( ! luxuriant =e/ cov]4 ,aft] de=e/ation ?is v5e] ( ri* soil 0 wa%$ by ! ra9s into ! dol9es or into ! few /ream c\rses ( ! region1 ?us leav+ a b>r5 tract :i* x w be all b impossible to reclaim 7plate #f ,a74 ,illu/ration3 ,,fig4 #aih4--,%>p ,k>r5 ( ! ,if5platte ,allgu 7aft] ,eck]t74 ,^u ! /eep] slopes ov] ! pur] lime/ones1 ! ra9 wat] runs away1 guid$ by ! jo9ts )9 ! rock4 ,!re is ?us et*$ out a m or less complete network ( n>r[ *annels 7,fig4 #aij1 p4 #aha71 betwe5 :i* ! remnants rise 9 %>p blades to produce a /ructure (t5 simulat$ ^u ! fissur$ surface ( a glaci] t has be5 melt$ 9 ! sun's rays 7,fig4 #dja74 ,^! almo/ impassable areas ( k>/ c\ntry are describ$ z ,s*ratt5 or ,k>r5feld] 7,fig4 #aih74 ,! ponore & ! polje4--,to-day l>ge areas ( ! ,k>/ are devoid ( surface /reams1 ne>ly all ! surface wat] f9d+ its way d[n ! crevices ( ! lime/one into cav]ns1 & !re fl[+ 9 subt]ranean c\rses4 ,! foot travel] 9 ! ,k>/ c\ntry is sometimes sudd5ly arre/$ to f9d a precipice yawn+ at 8 feet1 & look+ d[n a well-l op5+ to ! dep? ( a hundr$ feet or m1 he may see at ! bottom a l>ge riv] :i* em]ges f b5ea? ! "o wall to disappe> b5ea? ! o!r4 ,^! well-l %afts are 9 ! ,au/rian ,k>/ kn[n z ,ponores1 :ile to ! s\?w>d 9 ,greece !y are call$ ,katavo?r54 ,,plate #f4 ,illu/ration3 ,a4 ,b>r5 ,k>/ l&scape ne> ! fam\s ,adelsb]g grottoes4 7,photograph by ,i4 ,d4 ,scott47 ,illu/ration3 ,b4 ,surface ( a lime/one l$ge :]e jo9ts h be5 wid5$ ?r\gh solution4 ,syracuse1 ,n4,y4 7,photograph by ,i4 ,d4 ,scott47 ,else:]e ! k>/ riv] may em]ge f its subt]ranean c\rse 9 a broad] depress$ area b\nd$ by v]tical cliffs1 f :i* x lat] disappe>s b5ea? ! lime/one wall4 ,su* depressions ( ! k>/ are kn[n z polj51 & appe> 9 mo/ cases to be above ! d[n?r[n blocks 9 ! intricate fault mosaic ( ! region4 ,"s ( ^! /eeply wall$ inclosures h an area ( sev]al hundr$ squ>e miles1 & especially at ! "t ( ! spr+ sn[ melt+ !y are flood$ ) wat] & s trans=m$ into seasonal lakes 7,fig4 #aii & p4 #dbb74 ,x appe>s t at su* times ! cave gall]ies ( ! region ) _! local n>r[s are n able to c>ry (f all ! wat] :i* is conduct$ to !m2 & 9 consequ5ce !re is a tempor>y imp\nd+ ( ! flood wat]s 9 ^? portions ( ! riv]'s c\rse :i* are op5 to ! sky & m ext5d$4 ,! ru% ( wat] at su* times may br+ ! r$ clay into ! subt]ranean *annels 9 suffici5t quantity to clog ! passages4 ,! ,zirknitz ,lake usually has high wat] two or ?ree times a ye>1 & exceptionally ! flood+ has cont9u$ = a numb] ( ye>s4 ,x has ?us 9 "s di/ricts be5 necess>y to af=d relief to ! population ?r\gh ! con/ruction ( exp5sive dra9age tunnels4 ,illu/ration3 ,,fig4 #aii4--,! ,zirknitz seasonal lake )9 a polje ( ! ,k>/ 7aft] ,b]ghaus74 ,! conditions :i* are typifi$ 9 ! ,k>/ area to ! ea/ ( ! ,adriatic ,sea are enc\nt]$ also 9 _m o!r l&s2 z1 = example1 9 ! ,vor>lb]g & ,swiss ,alps1 9 ,lebanon1 & 9 ,sicily4 ,! return ( ! wat] to ! surface4--,wat] :i* has desc5d$ f ! surface & be5 !re held betwe5 imp]vi\s lay]s1 may be "u ! pressure ( its own weight or 8head02 & w lat] f9d its way upw>d1 x may be to ! surface or high]1 :]e a p]=ation is discov]$ 9 its o!rwise imp]vi\s cov]4 ,su* local p]=ations are produc$ naturally by l9es ( fracture or fault+ 7wid5$ at _! int]sections71 & artificially ?r\gh ! s9k+ ( deep wells4 ,! wat]1 :i* at ord9>y times rea*es ! surface ^u fissures1 is usually conc5trat$ locally at ! int]sections ( ! fracture network1 :]e x issues 9 l9es ( fissure spr+s 7,fig4 #bjj72 b at ! "t ( e>?quakes ! wat] may rise above ! surface 9 l9es ( f\nta9s 7p4 #hc71 or occasionally z %eets ( wat] :i* may m\nt "s t5s ( feet into ! air4 ,illu/ration3 ,,fig4 #bjj4--;,fissure spr+s arrang$ ^u l9es ( rock fracture at int]sections1 ,pomp]aug valley1 ,connecticut4 ,9 contra/ to ! fl[ ( surface spr+s1 :i* v>ies ) ! season ?r\gh wide ranges bo? 9 its volume & 9 temp]ature ( ! wat]1 ! volume ( fissure spr+s is b slightly affect$ by ! seasonal precipitation1 & ! wat] temp]ature is ma9ta9$ relatively con/ant4 ,rock is b a poor heat conductor1 & ! seasonal temp]ature *anges desc5d a few feet only into ! gr\nd4 ,?us wat] :i* rises f dep?s ( a few hundr$ feet only is apt to be icy cold1 :ile f great] dep?s ! effect ( ! e>?'s int]nal heat is app>5t 9 a uni=m b relatively high] temp]ature ( ! wat]4 ,su* 8w>m0 or !rmal spr+s are apt to conta9 consid]able m9]al matt] 9 solution1 bo? because ! wat] is f> travel$ & because its high] temp]ature has consid]ably increas$ its solv5t prop]ties4 ,x has long be5 recogniz$ t l9es ( junction ( diff]5t rock =mations at ! base ( m\nta9 ranges are localities favorable = ! occurr5ce ( !rmal spr+s4 ,^! junction l9es are usually )9 zones :]e by movem5t ^u fractures ! wide/ op5+s 9 ! rock h =m$1 & ! cat*m5t area ( ! neighbor+ m\nta9 highl& has suppli$ head = ! gr\nd wat]4 ,a map ( ! hot spr+s )9 ! ,great ,bas9 ( ! we/]n ,unit$ ,/ates w\ld pres5t 9 ! ma9 a map ( its pr9cipal faults4 ,artesian wells4--,f ! natural fissure spr+ an artesian well diff]s 9 ! artificial "* ( ! p]=ation ( ! imp]vi\s cov] to ! wat] lay]4 ,! wat] ( artesian wells may fl[ out at ! surface "u pressure1 or x may require pump+ to raise x f "s l[] level4 ,ideal conditions are furni%$ :]e ! geological /ructure ( ! di/rict is t ( a broad bas9 or syncl9e4 ,! wat] :i* falls 9 a neighbor+ upl& is "h imp\nd$ betwe5 two p>allel1 sauc]-l walls & w fl[ "u its head if ! upp] wall be p]=at$ at "s l[ level 7,fig4 #bja1 #c74 ,illu/ration3 ,,fig4 #bja4--,s*ematic diagrams to illu/rate ! diff]5t types ( artesian wells1 7#a7 ,a non-fl[+ well2 7#b7 fl[+ wells )\t bas9 /ructure caus$ by clogg+ ( ! p]vi\s =mation2 7#c7 fl[+ wells 9 an artesian bas94 ,! dott$ l9es are ! wat] levels )9 ! p]vi\s lay]s 7aft] ,*amb]l974 ,a monocl9al /ructure may furni% artesian conditions :5 ! g5]ally p]vi\s lay] has become clogg$ at a l[ level s z to hold back ! wat] 7,fig4 #bdh1 #b74 ,pump+ wells may be us$ successfully ev5 :5 su* clogg+ does n exi/1 = ! sl[-mov+ und]gr\nd wat] fl[s readily 9 ! direction ( all free outlets 7,fig4 #bja1 #a74 ,hot spr+s & geys]s4--,!rmal spr+s ^: temp]ature approa*es ! boil+ po9t ( wat] are kn[n z hot spr+s4 ,a geys] is a hot spr+ :i* int]mitt5tly ejects a column ( wat] & /eam4 ,bo? hot spr+s & geys]s are to be f\nd only 9 volcanic regions1 & appe> to be connect$ ) uncool$ masses ( silice\s lava4 ,9 two ( ! ?ree kn[n geys] regions1 ,icel& & ,new ,zeal&1 ! volcanoes ( ! neighborhood are /ill active1 & ! lavas ( ! ,yell[/one ,national ,p>k date f ! q rec5t geological p]iod :i* imm$iately prec$$ ! s-call$ 8,ice ,age40 ,:]ev] f\nd1 geys]s are 9 ! l[ levels along l9es ( dra9age :]e ! und]gr\nd wat] w\ld mo/ naturally reappe> at ! surface4 ,_! wat] has p5etrat$ to consid]able dep?s bel[ ! surface1 b has be5 *iefly heat$ by asc5d+ /eam or o!r vapors4 ,! wat] j\rney has be5 *iefly made along fissures1 z is %[n by ! cool spr+s :i* (t5 issue ne> !m4 ,?\gh "s hot spr+s & geys]s may disappe> f a di/rict1 o!rs are f\nd to be =m+1 & !re is no good reason to ?9k t geys]s are rapidly dy+ out1 z 0 at "o "t suppos$4 ,! action ( a geys] 0 fir/ satisfactorily expla9$ by ! great ,g]man *emi/ ,buns5 aft] he _h made /udies ( ! ,icel&ic geys]s1 & ! me*anics ( ! eruption 0 lat] /rik+ly illu/rat$ 9 ! laboratory by an artificial geys] con/ruct$ by ! ,iri% physici/ ,tyndall4 ,9 _m respects ?is action is l t ( ! ,/rombolian eruption )9 a c9d] cone1 s9ce x is connect$ ) ! viscosity ( ! fluid & ! resi/ance :i* ?is opposes to ! lib]ation ( ! develop+ vapor4 ,9 ! case ( ! geys]1 a column ( heat$ wat] /&s )9 a v]tical tube & is heat$ ne> ! bottom ( ! column4 ,illu/ration3 ,,fig4 #bjb4--;,cross section ( ,geysir1 ,icel&1 ) simultane\sly obs]v$ temp]atures record$ at ! left1 & ! boil+ temp]atures = ! same levels at ! "r 7aft] ,campbell74 ,?\gh ! wat] may at its surface h ! normal boil+ temp]ature & be !re 9 quiet ebullition1 ! boil+ po9t = all l[] levels is rais$ by ! weight ( ! column ( sup]9cumb5t liquid1 & s = a "t ! =mation ( /eam )9 ! mass is prev5t$4 ,9 ,fig4 #bjb is %[n a cross section ( ! ,icel&ic ,geysir f :i* our "n = su* ph5om5a has be5 d]iv$1 & to ?is section h be5 add$ ! actual obs]v$ temp]atures ( ! wat] at ! diff]5t levels z well z ! temp]atures at :i* boil+ c take place at ^! levels4 ,f ?is x w be se5 t at a dep? ( #de feet ! wat] is b #b ,c5tigrade bel[ its boil+ po9t4 ,a slight increase ( temp]ature at ?is level1 due to ! con/antly asc5d+ /eam1 w n only c>ry ?is lay] above ! boil+ po9t1 b ! expansion ( ! /eam )9 ! mass w elevate ! upp] lay]s ( ! wat] into zones :]e ! boil+ po9ts are l[]1 & ?us br+ ab\t a sudd5 & viol5t ebullition ( all ^! upp] portions4 ,?us is expla9$ ! almo/ univ]sal obs]vation t j be=e geys]s erupt ! hot wat] rises 9 ! b[ls & g5]ally ov]fl[s !m4 ,illu/ration3 ,,fig4 #bjc4--;,app>atus = simulat+ geys] action 9 ! lecture room 7by c\rtesy ( ,pr(essor ,b4 ,w4 ,sn[74 ,! wat] eject$ f ! geys] is consid]ably cool$ 9 ! air2 & aft] its return to ! tube mu/ be aga9 heat$ by ! asc5d+ vapors be=e ano!r eruption c occur4 ,! measure ( ! cool+1 ! "t necess>y to fill ! tube1 & ! supply ( ris+ /eam1 all play a "p 9 fix+ ! p]iod :i* sep>ates consecutive eruptions4 ,if ! top ( ! tube be n>r[$ f its av]age calib]1 z is commonly obs]v$ to be true ( ! geys]s )9 ! ,yell[/one ,national ,p>k1 ! escape ( ! /eam is fur!r h9d]$1 & frequ5t geys] eruption promot$4 ,an artificial geys] = demon/ration ( ! ph5om5on 9 ! lecture room is repres5t$ 9 ,fig4 #bjc4 ,! cut has be5 prep>$ f a photograph ( an app>atus design$ by ,pr(essor ,b4 ,w4 ,sn[ ( ! ,univ]sity ( ,wiscons94 ,9 ?is design ! tube is contract$ s z to h a top diamet] "o f\r? only ( :at x is at ! bottom1 :]e heat is directly appli$ by multiple ,buns5 lamps4 ,! wat] once suffici5tly heat$1 ?is artificial geys] erupts at regul> int]vals ( "t :i* are dep5d5t ^u ! dim5sions ( ! app>atus & ! quantity ( heat appli$4 ,9 case ( natural geys]s a consid]able quantity ( heat escapes betwe5 eruptions 9 /eam :i* issues quietly f ! b[l ( ! geys]4 ,if ?is heat be reta9$ by plugg+ ! m\? ( ! tube ) a b>r[ful ( turf1 z is sometimes done ) ! geys] ,/rokr 9 ,icel&1 eruption is promot$ & s takes place e>li]4 ,ano!r me?od ( secur+ ! same result is to increase ! viscosity ( ! wat] ?r\gh ! addition ( soap1 z 0 accid5tally discov]$ by a ,*9aman :o 0 utiliz+ ! geys] wat] 9 ! ,yell[/one ,p>k = laundry op]ations4 ,aft] ?is discov]y x became a common cu/om to 8soap0 ! ,yell[/one geys]s 9 ord] to make !m play2 b ?is me?od 0 prohibit$ "u heavy p5alty aft] ! disa/r\s eruption ( ! ,excelsior ,geys]4 ,! deposition ( silice\s s9t] by plant gr[?4--,geys]s are kn[n only f areas ( silice\s volcanic lava1 & ?is may p]haps h its cause 9 ! easi] solution ( ! geys] tube f su* mat]ials4 ,! silica dissolv$ 9 ! heat$ wat]s is aga9 deposit$ at ! surface to =m silice\s s9t] or geys]ite4 ,?is mat]ial =ms t]races surr\nd+ ! geys]s or is built up into m\nds :i* are (t5 q symmetrical1 su* z ^? ( ! ,bee ,hive & ,lone ,/> geys]s ( ! ,yell[/one ,p>k 7,fig4 #bjd74 ,illu/ration3 ,,fig4 #bjd4--;,cone ( silice\s s9t] built up ab\t ! m\? ( ! ,lone ,/> ,geys] 9 ! ,yell[/one ,national ,p>k4 ,! great] "p ( ?is sep>ation ( silica f ! heat$ geys] wat]s is due to ! action ( plants or alg t are able to gr[ 9 ! boil+ wat]s & :i* produce ! beautiful colors 9 ! l9+s to ! hot spr+s4 ,! wond]ful v>iety ( ! t9ts display$ is acc\nt$ = by ! fact t ! alg take on diff]5t colors at diff]5t temp]atures4 ,! silica is deposit$ f ! wat] 9 ! gelat9\s hydrat$ =m1 :i*1 h[ev]1 dries 9 ! sun to a :ite s&4 ,! gr[? )9 ! pools goes on 9 a mann] simil> to t ( a coral reef1 ! alg dy+ bel[ & !re becom+ encas$ 9 ! rock l9+ :ile /ill cont9u+ to gr[ ^u ! surface4 ,:]eas s9t] ( ?is nature1 :5 deposit$ by evaporation alone1 c produce a maximum ?ickness ( lay] ( a tw5tie? ( an in* ea* ye>1 ! gr[? f alga deposition )9 limit$ areas may be z mu* z eight in*es dur+ ! same p]iod4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xiv ,g5]al3-- ,f4 ,h4 ,,k+4 ,pr9ciples & ,conditions ( ! ,movem5ts ( ,gr\nd ,wat]1 #ai? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahii1 ,pt4 ii1 pp4 #ei-bid1 pls4 #f-af4 ,c4 ,s4 ,,sli*t]4 ,! ,motions ( ! ,und]gr\nd ,wat]s1 ,wat] ,supply ,pap] ,no4 #fg1 ,u4 ,s4 ,geol4 ,surv41 #aijb1 pp4 #a-ajf1 pls4 #a-h2 ,field ,measurem5ts ( ! ,rate ( ,movem5t ( ,und]gr\nd ,wat]s1 ibid41 ,no4 #adj1 #aije1 pp4 #a-abb1 pls4 #a-ae4 ,m4 ,l4 ,,full]4 ,occurr5ce ( ,und]gr\nd ,wat]1 ibid44 ,no4 #aad1 #aije1 pp4 #ah-dj1 pls4 #d2 ,bibliographic review & index ( pap]s relat+ to und]gr\nd wat]s publi%$ by ! ,unit$ ,/ates ,geological ,survey1 #ahgi-aijd1 ibid41 ,no4 #abj1 #aije1 pp4 #a-abh4 ,cav]ns3-- ,e4 ,a4 ,,m>tel4 ,les abimes1 les eaux s\t]ra9es1 les cav]nes1 les s\rces1 la splologie4 ,delagrave1 ,p>is1 pp4 #egh4 7,lavi%ly illu/rat$47 ,h4 ,c4 ,,hovey4 ,celebrat$ ,am]ican ,cav]ns4 ,c9c9nati1 #ahif1 pp4 #bbh2 ,! ,mammo? ,cave ( ,k5tucky4 ,l\isville1 #ahig1 pp4 #aaa4 ,j4 ,w4 ,,be$e4 ,cycle ( ,subt]ranean ,dra9age 9 ! ,bloom+ton ,quadrangle1 ,proc4 ,ind4 ,acad4 ,sci41 #aiaj1 pp4 #a-ca4 ,k>/ conditions3-- ,j4 ,,cvijic4 ,das ,k>/phnom51 ,geogr4 ,abh41 vol4 #e1 #ahic4 ,,mile ,,*aix4 ,la topographie du des]t de plat 7,hautes ,savoie71 ,le ,globe1 vol4 #cd1 #ahie1 pp4 #a-dd1 pls4 #a-af1 pp4 #bag-ccj4 ,w4 ,v4 ,,knebel4 ,hhl5kunde mit ,b]cksi*tigung d] ,k>/phnom5e4 ,vieweg1 ,brauns*weig1 #aijf1 pp4 #bbb4 ,a4 ,,grund4 ,die ,k>/hydrographie1 ,/udi5 aus ,we/bosni51 ,geogr4 ,abh41 vol4 #g1 ,no4 #c1 #aijc1 pp4 #bjj4 ,,mile ,,*aix-,,du ,,bois et ,,&r ,,*aix4 ,contribution a l'tude des lapies en ,c>niole et au ,/e9]nes ,me]1 ,le ,globe1 vol4 #df1 #aijg1 pp4 #ag-ef1 pls4 #bf4 ,p4 ,,arb5z4 ,die ,k>r5bildung5 ges*ild]t am ,beispiele d] ,k>r5feld] bei d] ,frutt 9 ,kanton ,obwald5 7,s*weiz74 ,deuts*4 ,alp5zeitung1 ,muni*1 #aiji1 pp4 #a-i4 ,f4 ,,katz]4 ,k>/ und ,k>/hydrographie4 ,s>ejevo1 #aiji1 pp4 #ie4 ,m4 ,,neumayr4 ,erdges*i*te1 vol4 #a1 pp4 #ejj-eaj4 ,e4 ,,de ,,m>tonne4 ,trait de ,gographie ,physique1 pp4 #dfb-dgb 7excell5t summ>ies 9 ?is & ! la/ ref]5ce74 ,e4 ,a4 ,,m>tel4 ,! ,l& ( ! ,causses1 ,appala*ia1 vol4 #g1 #ahic1 pp4 #ah-adi1 pls4 #d-ac4 ,fissure spr+s3-- ,a4 ,c4 ,,peale4 ,natural ,m9]al ,wat]s ( ! ,unit$ ,/ates1 #ad? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ii1 #ahid1 pp4 #di-hh4 ,,william ,h4 ,,hobbs4 ,! ,new>k ,sy/em ( ! ,pomp]aug ,valley4 ,connecticut1 #ba/ ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 iii1 #aija1 pp4 #ia-ic4 ,artesian wells3-- ,t4 ,c4 ,,*amb]l94 ,requisite & ,qualify+ ,conditions ( ,artesian ,wells1 #e? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #aca-agc4 ,hot spr+s & geys]s3-- ,a4 ,c4 ,,peale4 ,yell[/one ,p>k1 ,!rmal ,spr+s1 #ab? ,ann4 ,rept4 ,geol4 & ,geogr4 ,surv4 ,t]4 7,hayd571 ,pt4 ii1 ,sec4 ii1 pp4 #fc-ded 7_m plates & maps74 ,w4 ,h4 ,,we$4 ,geys]s1 ,rept4 ,smi?son4 ,in/41 #ahia1 pp4 #afc-agh4 ,,arnold ,,hague & ,w4 ,h4 ,,we$ 7on hot spr+s & geys]s ( ,yell[/one ,national ,p>k71 ,c4 ,r4 ,cong4 ,gol4 ,int]n41 ,wa%+ton1 #ahia1 pp4 #cdf-cfc4 ,w4 ,h4 ,,we$4 ,=mation ( ,trav]t9e & ,silice\s ,s9t] by ! ,vegetation ( ,hot ,spr+s1 #i? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhi1 pp4 #fac-fgf1 pls4 #gh-hg4 ,m4 ,,neumayr4 ,erdges*i*te1 vol4 #a1 pp4 #ejj-eaj4 ,,arnold ,,hague4 ,soap+ ,geys]s1 ,trans4 ,am4 ,in/4 ,m94 ,eng41 vol4 #ag1 #ahhi1 pp4 #edf-eec4 ,,john ,,tyndall4 ,heat z a ,mode ( ,motion1 ,new ,york1 #ahgc1 pp4 #aae-aba 7artificial geys]74 ,,*apt] ,,xv ,,sun ,,& ,,w9d ,,9 ,,! ,,l&s ,,( ,,infrequ5t ,,ra9s ,! law ( ! des]t4--,x is well to keep ev] 9 m9d t !re is no univ]sal law :i* dom9ates ,nature's processes 9 all ! sections ( h] realm4 ,^? *anges :i*1 because (t5 obs]v$1 are mo/ famili>1 may n be ( g5]al application1 = ! reason t ! areas habitually occupi$ by highly civiliz$ races toge!r comprise b a small portion ( ! e>?'s surface4 ,9 ! dank tropical jungle1 ^u ! va/ arid s& pla9s1 & 9 ! cold :ite spaces ne> ! poles1 ,nature has in/itut$ peculi> & widely diff]5t processes4 ,! fundam5tal condition ( ! des]t is aridity1 & ?is necessitates an exclusion f x ( all save ! exceptional ra9 cl\d4 ,?us des]ts are wall$ 9 by m\nta9 ranges :i* s]ve z b>ri]s to int]cept ! moi/ure-br++ cl\ds4 ,!y are 9 consequ5ce sauc]-%ap$ depressions1 (t5 ) %ort m\nta9 ranges ris+ out ( ! bottoms1 & su* ra9 z falls )9 ! inclosure is l>gely ^u ! bord]s4 ,( ?is ra9fall none fl[s out f ! des]t1 = ! wat] is l>gely return$ to ! atmosph]e ?r\gh evaporation4 ,! des]t hi/ory is ?us begun 9 isolation f ! sea f :i* ! cl\d moi/ure is d]iv$1 a balance be+ /ruck betwe5 infl[ & evaporation4 ,yet if des]ts h no outlets1 x is n true t !y h no riv]s4 ,^! are occasionally p]man5t1 (t5 p]iodic1 b g5]ally ephem]al & viol5t4 ,! *>act]i/ic dra9age ( des]ts comes z ! imm$iate result ( sudd5 cl\dbur/4 ,z a consequ5ce1 ! des]t /ream fl[s f ! m\nta9 wall *ok$ ) s$im5t1 & ent]+ ! depress$ bas91 is = ! mo/ "p ei!r suck$ d[n into ! floor or evaporat$ & return$ to ! atmosph]e4 ,! dissolv$ mat]ial :i* 0 c>ri$ 9 ! wat] is ev5tually left 9 sal9e deposits1 & ! great burd5 ( s$im5t accumulates 9 ?ick /ratifi$ masses :i* 9 magnitude out/rip ! l>ge/ deltas 9 ! ocean4 ,! self-regi/]+ gauge ( pa/ climates4--,f ! initiation ( ! des]t 9 its isolation f ! l&s tribut>y to ! sea1 its hi/ory becomes an individual & indep5d5t "o4 ,an increas+ quantity ( ra9fall w be m>k$ by l>g] infl[ to ! bas91 & ! lakes :i* =m 9 its l[e/ depression w1 z a consequ5ce1 rise & exp& ov] l>g] areas4 ,a contr>y climatic *ange w br+ ab\t a l[]+ ( ! lakes & leave beh9d ! m>ks ( =m] %orel9es above ! wat] level 7,fig4 #bje74 ,des]ts are ?us 9 a s5se self-regi/]+ climatic gauges ^: records g back f> beyond ! hi/oric pa/4 ,f !m x is le>n$ t !re h be5 alt]nat+ p]iods ( l>g] & small] precipitation1 :i* are ref]r$ to z pluvial & int]pluvial p]iods4 ,illu/ration3 ,,fig4 #bje4--;,=m] %ore l9es on ! m\nta9 wall surr\nd+ ! des]t ( ! ,great ,bas94 ,view f ! temple 9 ,salt ,lake ,city 7aft] ,gilb]t74 ,f su* records x is le>n$ t ! ,great ,bas9 ( ! we/]n ,unit$ ,/ates 0 at "o "t occupi$ by two great des]t lakes1 ! "o 9 ! ea/]n portion be+ kn[n z ,lake ,bonneville 7,fig4 #bjf74 ,) ! desiccation :i* foll[$ ^u ! s]ies ( pluvial p]iods1 :i* 9 o!r latitudes result$ 9 great cont95tal glaci]s & has become kn[n z ! ,glacial ,p]iod1 ?is =m] des]t lake dri$ up to ! limits ( ,great ,salt ,lake & a few small] isolat$ bas9s4 ,betwe5 #ahej & #ahfi ! wat]s ( ,great ,salt ,lake 7 ris+1 :ile f #ahgf to #ahij _! level 0 fall+1 ?\gh subject to p]iodic fluctuations1 & 9 rec5t ye>s ! wat]s ( ! lake h ris5 s high z to pass all records s9ce ! occupation ( ! c\ntry4 ,z a consequ5ce ! s-call$ ,salt ,lake 8cut-(f0 ( ! ,union ,pacific ,railway1 con/ruct$ at great exp5se across a %all[ portion ( ! lake1 has be5 ov]fl[$ by its wat]s4 ,! ,sawa ,lake 9 ! ,p]sian ,des]t1 :i* disappe>$ "s five hundr$ ye>s ago1 aga9 came into exi/5ce 9 #ahhh s z to cov] ! c>avan r\te to ,teh]an4 ,illu/ration3 ,,fig4 #bjf4--,map ( ! =m] ,lake ,bonneville 7dott$ %ores71 & ! b\nd>ies ( ! ,great ,salt ,lake ( #ahfi 7small] area7 & t ( ! pres5t 7aft] ,b]ghaus74 ,! record 9 ! rocks ( ! di/ant pa/ reveals ! fact t 9 "s =m] des]ts b>ri]s 71 9 ! c\rse ( "t1 brok5 d[n1 ) ! result t an invad+ sea ent]$ ?r\gh ! brea*$ wall4 ,! result 0 ! sudd5 de/ruction ( l& life1 ! rema9s ( :i* are pres]v$ 9 8bone b$s01 n[ cov]$ by true m>9e deposits4 ,a /ill lat] episode ( ! hi/ory 0 begun :5 ! sea _h disappe>$ & l& animals aga9 roam$ above ! e>li] des]t4 ,su* an alt]nation ( m>9e deposits ) ! rema9s ( l& plants & animals 9 ! deposits ( ! ,p>is ,bas91 l$ ! great ,cuvi] to 8 belief t geologic hi/ory 0 compris$ ( a succession ( cataclysms 9 :i* life 0 alt]nately de/roy$ & re-creat$ 9 new =ms--a view :i* lat]1 "u ! p[]ful influ5ce ( ,lyell & ,d>w91 gave way to t ( m gradual *anges & ! evolution ( life =ms4 ,"s *>act]i/ics ( ! des]t wa/es4--,! great /ret*es ( ! arid l&s h be5 (t5 comp>$ to ! ocean1 & ! ,b$\9's camel is kn[n z 8! %ip ( ! des]t40 ,?\gh a deceptive resemblance = ! mo/ "p1 ! comp>ison is n )\t its value4 ,bo? are clos$ bas9s1 & x is 9 ?is respect t ! des]t & ! ocean may be said to mo/ resemble ea* o!r1 = none ( ! wat] & none ( ! s$im5t is lo/ to ei!r except z b\nd>ies are1 ) ! progress ( "t1 transpos$ or de/roy$4 ,flatness ( surface & monotony ( sc5]y bo? h 9 common1 & ! wat]s & ! s& are 9 ea* case salt2 yet ! ocean1 f ! tropics to ! poles1 has ! same salts 9 ess5tially ! same proportions1 :ile 9 ! des]t ! wide/ v>iations are f\nd bo? 9 ! salts :i* are pres5t & 9 _! relative quantities4 ,^u ! bord]s ( ! ocean are f\nd ridges ( yell[ s& heap$ up by ! w9d1 b ^! ramp>ts are small 9 comp>ison to ^? :i* 9 des]ts are f\nd ^u ! bord]s 7plate #g ,a74 ,! des]t is a l& ( geographic p>adoxes4 ,z ,wal!r has po9t$ out1 we h ra9 9 ! des]t :i* does n wet1 spr+s :i* yield no brooks1 riv]s )\t m\?s1 =e/s pres]v$ 9 /one1 lakes )\t outlets1 valleys )\t /reams1 lake bas9s )\t lakes1 depressions bel[ ! level ( ! sea yet b>r5 ( wat]1 int5se wea!r+ ) no mantle ( dis9tegrat$ rock1 a decomposition ( ! rocks f )9 in/ead ( f )\t1 & valleys :i* bran* sometimes up/ream & sometimes d[n4 ,)9 ! des]ts curi\s mu%room-l remnants ( erosion af=d a local relief f ! se>*+ rays ( ! des]t sun4 ,pocket-l op5+s l>ge en\gh = a h]mit's habitation are holl[$ out by ! w9d f ! dis9tegrat$ rock masses4 ,amphi!at]s op5 out f little erosion valleys or wadi1 & isolat$ outli]s ( ! m\nta9s /& l s5t9els be=e _! massive fronts4 ,because ( ! g5]al abs5ce ( cl\ds above a des]t1 no %ield su* z is common 9 humid regions is provid$ aga9/ ! bl9d+ int5sity ( ! sun's rays4 ,sun temp]atures z high z #ahj ,fahr5heit h be5 regi/]$ ov] ! des]ts ( we/]n ,africa4 ,e "o is famili> ) ! fact t a blanket ( ?ick cl\ds is a prev5tion ( fro/s at night1 =1 ) ! sett+ ( ! sun & ! consequ5t radiation ( heat f ! e>?1 ^! rays are int]cept$ by ! cl\ds1 return$ & re-return$ 9 _m successive ex*anges4 ,ov] des]t regions ! abs5ce ( any su* blanket ( moi/ure is responsible = ! rem>kable falls ( temp]ature at sunset4 ,?\gh %ortly be=e temp]atures ( #ajj ,fahr5heit or great] may h be5 measur$1 x is n uncommon = wat] to freeze dur+ ! foll[+ night4 ,mu* ! same conditions ( sudd5 temp]ature *ange ) nightfall are exp]i5c$ 9 high m\nta9s :5 "o has asc5d$ above ! blanket+ cl\ds4 ,illu/ration3 ,,fig4 #bjg4--;,borax deposits ^u ! floor ( ,dea? valley1 ,cali=nia 7aft] a photograph by ,fairbanks74 ,dry wea!r+--! r$ & br[n des]t v>ni%4--,9 des]t l&s ! fi]ce rays ( ! sun suck up all ! available moi/ure1 & ! wat] table may be hundr$s ( feet bel[ ! surface4 ,roots ( trees a hundr$ feet or m 9 l5g? h be5 f\nd to te/ify to ! fi]ce /ruggle ( ! des]t plant ) ! arid conditions4 ,9 humid regions ! meteoric wat] dissolves ! m soluble sodium salts ne> ! surface ( ! rock & c>ries !m out to ! ocean1 :]e !y add to ! saltness ( ! sea4 ,9 ! des]t ! r>e precipitations prev5t an outfl[1 b ! sun's /rong rays suck out ) ! moi/ure ! salts f )9 ! rock1 & evaporat+ ^u ! surface1 ! salts are left z a coat ( 8alkali01 :i* is 9 "p c>ri$ away on ! w9d & 9 "p wa%$ (f 9 "o ( ! r>e cl\dbur/s4 ,9 ei!r case ^! con/itu5ts f9d _! way to ! l[e/ depressions ( ! bas91 :]e !y contribute to ! sal9e deposits ( ! des]t lakes 7,fig4 #bjg74 ,illu/ration3 ,,fig4 #bjh4--;,holl[$ =ms ( wea!r$ granite 9 a des]t ( c5tral ,asia 7aft] ,wal!r74 ,c]ta9 ( ! sal9e con/itu5ts ( ! rocks1 z !y are ?us drawn out by ! sun's rays1 fuse ) ! rock at ! surface to =m a d5se br[n sub/ance ) smoo? surface coat1 kn[n z des]t v>ni%4 ,)9 ! int]ior a portion ( ! salts cry/allize )9 ! capill>y fissures1 & l wat] freez+ )9 a pipe1 !y r5d ! walls ap>t4 ,z a direct consequ5ce ( ?is dis9tegrat+ process ! int]ior ( rock masses may crumble into s&2 & if ! h>d %ell ( v>ni% be brok5 at any po9t1 ! w9d makes its entrance & removes ! int]ior portion s z to leave a holl[ %ell--! *>act]i/ic 8pocket rock0 7,fig4 #bjh7 ( ! des]t4 ,! nummulitic lime/one ( ,mokkatan & _m ( ! great hewn blocks ( ,egyptian lime/one s\nd holl[ "u ! tap ( ! hamm]1 & :5 brok51 !y reveal a %ell a few in*es only 9 ?ickness 7,fig4 #bji74 ,illu/ration3 ,,fig4 #bji4--;,holl[ hewn blocks 9 a wall 9 ! ,wadi ,gu]raui 7aft] ,wal!r74 ,! br[n des]t v>ni% is "o ( ! mo/ *>act]i/ic m>ks ( an arid c\ntry4 ,x is f\nd 9 all des]ts "u mu* ! same conditions1 & is especially apt to be pres5t 9 s&/one4 ,:5 scrat*$1 ! surface ( ! rock becomes ei!r *]ry-r$1 indicat+ anhydr\s f]ric oxide1 or x is yell[i%1 due to ! hydrat$ iron oxide :i* we "k z iron ru/4 ,?us x is se5 t ! s&s ( des]ts1 9 contra/ to ^? yield$ by o!r processes )9 humid regions1 h a *>act]i/ic r$ color1 & ?is may v>y f br[ni% r$ ^u ! "o h& to a ri* c>m9e ^u ! o!r4 ,! me*anical breakd[n ( ! des]t rocks4--,! *emical *anges ( decomposition )9 des]t rocks are1 z we h se51 l>gely due to ! action ( conc5trat$ solutions ( salts at high temp]atures4 ,t !re is a c]ta9 me*anical r5d+ ( ^! rocks1 due to ! 8freez+0 ( salts )9 ! capill>y fissures1 has be5 already m5tion$4 ,a fur!r /ra9 effect arises 9 rocks l granite1 :i* are a mixture ( diff]5t m9]als4 ,heat$ to a high temp]ature dur+ ! day & cool$ ?r\gh a consid]able range at night1 ! diff]5t m9]als alt]nately exp& & contract at diff]5t rates & by diff]5t relative am\nts1 s t /ra9s are set up1 t5d+ to te> !m ap>t4 ,! effect ( ^! /ra9s is ?us a surface crumbl+ ( rocks4 ,b rock is1 z already po9t$ out1 a relatively poor conductor ( heat1 & h5ce x is a relatively ?9 sk9 only :i* passes ?r\gh ! daily r\nd ( wide temp]ature range4 ,?is out] %ell :5 heat$ is exp&$1 & s t5ds to peel (f1 or exfoliate1 l ! out] sk9 ( an onion4 ,! process is !re=e describ$ z exfoliation4 ,9 all rocks ( homog5e\s texture ! cont9u$ action ( ?is process results 9 convexly sph]ical surfaces1 ! mat]ial scal$ (f 9 ! process rema9+ z a slope or talus :i* surr\nds ! project+ knob 7,fig4 #baj74 ,nak$1 ^! project+ domes rise above ! rim ( dbris at _! bases4 ,n a p>ticle ( du/ adh]es to ! fre% rock surface--no dirt int]f]es ) its gl>+ :it5ess4 ,yet close at h& lie masses ( dbris into :i* wells may be c>ri$ to dep?s ( m ?an six hundr$ feet )\t enc\nt]+ ei!r solid rock or gr\nd wat]4 ,! b>e walls ( granite sometimes m\nt upw>ds = ?\s&s ( feet into ! air1 z /eep & z inaccessible z ! squ>$ t[]s ( ! ,tyrolean ,dolomites4 ,illu/ration3 ,,fig4 #baj4--,smoo? granite domes %ap$ by exfoliation & surr\nd$ by a rim ( talus4 ,gebel ,k>sala1 ,nubian ,des]t 7aft] ,wal!r74 ,rock is su* a poor conductor ( heat t special /ra9s are set up at ! m>g9 ( sunlight & %ade4 ,?is localization ( ! dis9tegration on ! m>g9 ( ! %ad$ portions ( rock masses is kn[n z %ad[ wea!r+ 7see ,fig4 #bae1 p4 #bjf74 ,!re is1 h[ev]1 /ill ano!r me*anical dis9tegrat+ process *>act]i/ic ( ! des]t regions1 :i* is likewise dep5d5t ^u ! sudd5 *anges ( temp]ature4 ,ra9s1 ?\gh !y may n occur = a ye> or m1 come z sudd5 d[np\rs ( great volume & viol5ce4 ,rock masses1 :i* are highly heat$ b5ea? ! des]t sun1 if sudd5ly da%$ ) wat]1 may be r5t ap>t by ! diff]5tial /ra9s set up ne> ! surface4 ,t rocks may be easily r5t z a result ( sudd5 *ill+ is well kn[n to our ,nor!rn f>m]s1 :o are accu/om$ to rid !mselves ( objectionable b[ld]s by fir/ build+ a fire ab\t !m & !n da%+ wat] ^u _! surface4 ,?us split into fragm5ts1 ev5 ! l>g] b[ld]s may be h&l$ & s remov$ f ! f>m+ l&4 ,! natural process ( rock r5d+ by ! occasional cl\dbur/ may be describ$ z diffission4 ,blocks z mu* z tw5ty-five feet 9 diamet] h be5 obs]v$ 9 ! des]t ( we/]n ,texas1 soon aft] be+ brok5 into sev]al fragm5ts at ! "t ( a d[np\r ( ra9 7,fig4 #baa74 ,illu/ration3 ,,fig4 #baa4--;,granite blocks 9 ! ,si]ra de los ,dolores ( ,texas1 r5t into sev]al fragm5ts by ! da% ( ra9 7aft] ,wal!r74 ,! natural s& bla/4--,because ( ! sauc]-l %ape1 ! va/ expanse1 & ! abs5ce ( w9d breaks1 ! pot5cy ( w9d z a geological ag5t is 9 des]t areas n easily ov]e/imat$4 ,:ile mo/ ( its "w is accompli%$ ) ! aid ( tools1 x has be5 prov5 t ev5 )\t ?is help1 consid]able "w is done ?r\gh ! friction ( ! w9d alone1 p>ticul>ly :5 mov+ z p[]ful eddies 9 cracks & crannies4 ,?is we> ( ! w9d1 unaid$ by cutt+ tools1 is kn[n z deflation4 ,! great] "w ( ! w9d is1 h[ev]1 accompli%$ ) ! aid ( l>g] or small] rock p>ticles1 ! s& & du/1 ) :i* x is s g5]ally *>g$ above ! des]ts4 ,unprotect$ by any mat ( vegetation ! mat]ials ( ! des]t surface are easily lift$ & are con/antly migrat+ ) ! w9d4 ,! f9e/ du/ is rais$ high into ! air1 & is c>ri$ beyond ! m>g9al b>ri]s1 b none ( ! s& or co>s] mat]ials ev] passes beyond ! bord]s4 ,illu/ration3 ,,fig4 #bab4--8,mu%room rock0 f a des]t 9 ,wyom+ 7aft] ,fairbanks74 ,! effici5cy ( ?is s& z a cutt+ tool :5 c>ri$ by ! w9d is directly proportion$ to ! size ( ! gra91 s9ce ) l>g] fragm5ts a heavi] bl[ is /ruck :5 c>ri$ at any giv5 velocity4 ,^! m effective gra9s are1 h[ev]1 n lift$ f> above ! gr\nd1 b advance ) a squirm+ or hopp+ motion1 mu* z d ! l>g] pebbles ^u ! bottom ( a riv] at ! "t ( a spr+ fre%et4 ,to quote ,pr(essor ,wal!r3 8,:oev] has _h ! opportunity to travel ov] a surface ( dune s& :5 a /rong w9d is bl[+ has f\nd x easy to conv9ce himself ( ! gr9d+ action ( ! w9d4 ,at su* times ! gr\nd becomes alive1 ev]y:]e ! s& is creep+ ov] ! surface ) snake-l squirm+s1 & ! eye quickly tires ( ^! wri?+ movem5ts ( ! curr5ts ( s& & _c long endure ! sc5e40 ,illu/ration3 ,,fig4 #bac4--,w9dkant5 %ap$ by ! des]t s& bla/ 7aft] ,*amb]l9 & ,salisbury74 ,a direct consequ5ce ( ?is re/riction ( ! m effective cutt+ tools to ! lay] ( air j above ! gr\nd1 is ! /rong t5d5cy to cut away all project+ masses ne> _! bases4 ,! 8mu%room rocks01 :i* are s *>act]i/ic ( des]t l&scapes1 h be5 %ap$ 9 ?is mann] 7,fig4 #bab74 ,ano!r product ( ! des]t s& bla/ is ! s-call$ ,w9dkante 7w9d-edge7 or ,dreikante 7?ree-edge71 a pebble :i* is usually %ap$ 9 ! =m ( a pyramid 7,fig4 #bac74 ,:5ev] a rock face1 op5 to direct attack by ! drift+ s&1 is con/itut$ ( p>ts :i* h diff]5t h>dness1 ! bla/ ( s& pecks away at ! s(t] places & leaves ! h>d] ones 9 relief4 ,?us is produc$ ! well-kn[n 8/one lattice0 ( ! des]t 7,fig4 #bad74 ,p>ticul>ly ^u ! neck ( ! great ,sph9x h ! fly+ s& gra9s1 by remov+ ! s(t] lay]s1 br\ght ! s$im5t>y /ructures ( ! s&/one into /rong relief4 ,illu/ration3 ,,fig4 #bad4--,! 8/one lattice0 ( ! des]t1 ! "w ( ! natural s& bla/ 7aft] ,wal!r74 ,:5 guid$ bo? by planes ( s$im5tation & planes ( jo9t+1 =ms ( a v high degree ( ornam5tation are develop$4 ,"s ( ! mo/ rem>kable =ms are due to ! protection af=d$ to ! sun-expos$ surfaces by ! %ell ( des]t v>ni%4 ,9 ! %ad$ portions ( project+ masses !re is no su* protection1 & "h ! s& bla/ ins9uates itself into e crack & cranny4 ,9 ?is x is aid$ by %ad[ wea!r+ due to ! diff]5tial /ra9s set up at ! bord] ( ! exp&$ sun-heat$ surface4 ,z a result1 project+ rock masses are sometimes et*$ away b5ea? & give ! effect ( a squatt+ animal4 ,^! =ms1 due to %ad[ erosion1 h also be5 lik5$ to project+ faucets4 7,fig4 #bae74 ,illu/ration3 ,,fig4 #bae4--,project+ rock c>v$ by ! drift+ s& into ! =m ( a c\*ant animal z a result ( %ad[ wea!r+ & erosion4 ,cut 9 granite on ! nor? ,indian ,des]t 7aft] ,wal!r74 ,worn by its impact ^u neighbor+ s& gra9s :ile 9 transport1 b mu* m z x is ?r[n aga9/ ! gr\nd or h>d rock surfaces1 ! w9d-driv5 or eolian s& is at la/ worn into smoo?ly r\nd$ granules :i* approa* ! =m ( a sph]e4 ,comp>$ to ! surface :i* sea s& acquires by attrition1 ?is %ap+ process is mu* ! m effici5t1 s9ce 9 ! wat] ! bea* s& is buoy$ up & is m effectively cu%ion$ aga9/ its neighbor+ gra9s4 ,! gra9s ( bea* s& :5 exam9$ "u a microscope are f\nd to be mu* m irregul> 9 =m & usually display ! orig9al fracture surfaces only 9 "p abrad$4 ,illu/ration3 ,,fig4 #baf4--;,cliffs 9 loess #bjj feet 9 height :i* exhibit ! *>act]i/ic v]tical jo9t+ 7aft] von ,ri*t(574 ,! du/ c>ri$ out ( ! des]t4--,:51 /&+ ^u ! m\nta9 wall t surr\nds a des]t1 ! travel] gazes out to w9dw>d ov] ! great depression1 8 field ( view is g5]ally obscur$ by ! yell[ haze ( ! du/ cl\ds mov+ across ! m>g9s4 ,^u ! m\nta9 flanks & ext5d+ f> outside ! bord]s1 ?is cl\d ( du/ settles z a %r\d+ mantle ( impalpable yell[ p[d]1 :i* is kn[n z loess4 ,^! deposits are cont9ually deep5+1 & h sometimes accumulat$ until !y are hundr$s or ev5 ?\s&s ( feet 9 ?ickness4 ,be=e rea*+ its f9al re/+ place ! du/ ( ?is deposit may h settl$ _m times1 & has c]ta9ly be5 9 "p r$i/ribut$ by ! /reams ne> ! des]t m>g94 ,9 x are ! +r$i5ts :i* are necess>y = ! n\ri%m5t ( plants1 & x con/itutes ! mo/ important ( natural soils4 ,cont9ually f$ by new deposits f ! des]t1 & ref]tiliz$ f bel[ by a natural process s soon z ! upp] lay]s become impov]i%$1 x requires no artificial f]tilization4 ,)\t artificial aids ! loess ( nor!rn ,*9a has be5 till$ = ?\s&s ( ye>s )\t any signs ( exhau/ion4 ,illu/ration3 ,,fig4 #bag4--;,a caon 9 loess worn by traffic & w9d4 ,a highway 9 nor!rn ,*9a 7aft] von ,ri*t(574 ,?\gh easily pulv]iz$ betwe5 ! f+]s1 loess is none ! less *>act]iz$ by a p]fect v]tical jo9t+ & /&s on v]tical faces z does ! solid rock 7,fig4 #baf71 b x is absolutely devoid ( lay]s or b$d+4 ,its capacity ( /&+ 9 v]tical cliffs ! loess owes to a nev] fail+ cont5t ( lime c>bonate :i* acts z a cem5t1 & to a peculi> por\s /ructure caus$ by capill>y canals t run v]tically ?r\gh ! mass1 bran*+ l rootlets & l9$ ) c>bonate ( lime4 ,?is texture once de/roy$1 loess resolves itself into a common /icky clay4 ,by ! feet ( pass+ animals or by :eels ( vehicles1 ! loess is cru%$1 & a portion is lift$ & c>ri$ away by ! w9d4 ,?us 9 ! c\rse ( "t roadways s9k deep into ! mass z /eep-wall$ caons 7,fig4 #bag74 ,a portion ( ! n[ /ructureless clay rema9+ ^u ! roadway is at ! "t ( ! ra9s trans=m$ into a ?ick mud :i* makes travel+ all b impossible1 ?\gh be=e its /ructure has be5 de/roy$ ! loess is p]fectly dra9$ to ! bottom ( its deposits4 ,! p>ticles :i* compose ! loess are %>ply angul> qu>tz fragm5ts1 s f9e t all b a few gra9s c be rubb$ into ! pores ( ! sk94 ,f9e scales ( mica1 su* z are easily lift$ by ! w9d1 are dissem9at$ uni=mly ?r\gh\t ! mass4 ,! only inclosures :i* are arrang$ 9 lay]s consi/ ( irregul>ly %ap$ concretions ( clay4 ,^! %[ a /rik+ resemblance to g+] roots & are call$ by ! ,*9ese 8/one g+]01 ?\gh !y are else:]e m g5]ally kn[n by _! ,g]man "n ( ,loessmnn*51 or loess dolls4 ,^! concretions are s dispos$ 9 ! loess t _! long] axes are v]tical1 & !y 7 evid5tly sep>at$ f ! mass & n deposit$ ) x4 ,,*apt] ,,xvi ,,! ,,features ,,9 ,,des]t ,,l&scapes ,illu/ration3 ,,fig4 #bah4--;,diagrams to illu/rate ! effects ( ob/ructions ( diff]5t types 9 arre/+ w9d-driv5 s&4 a1 ,an unyield+ ob/ruction :i* p]mits ! w9d to pass ?r\gh x2 b1 a flexible & p]=at$ ob/ruction2 c1 an unyield+ clos$ b>ri] 7aft] ,s*ulze74 ,! w&]+ dunes4--,ov] ! broad expanse ( ! des]t1 s& & du/1 & occasionally gypsum f ! sal9e deposits1 are ev] migrat+ ) ! w9d2 on quiet days 9 ! eddy+ 8s& devils01 b especially dur+ ! t]rify+ s& /orms su* z 9 ! w9dy season d>k5 ! air ( nor!rn ,*9a & s\!rn ,man*uria4 ,?is drift ( ! s& is halt$ only :5 an ob/ruction is enc\nt]$--a project+ rock1 a bu%1 or a bun* ( grass1 or aga9 ! build+s ( a city or a t[n4 ,! mann] 9 :i* ! s& is arre/$ by ob/acles ( diff]5t k9ds is ( great int]e/ & importance1 & is utiliz$ 9 rais+ def5ses aga9/ its encroa*m5ts4 ,if ! ob/acle is unyield+ b all[s "s ( ! w9d to pass ?r\gh x1 no eddies are produc$ & ! s& is deposit$ bo? to w9dw>d & to leew>d ( ! ob/ruction to =m a fairly symmetrical m\nd 7,fig4 #bah a74 ,an ob/ruction :i* yields to ! w9d causes ! s& to deposit 9 a m\nd :i* is l>gely to leew>d ( ! ob/ruction 7,fig4 #bah b74 ,a solid wall1 on ! o!r h&1 by induc+ eddies1 is at fir/ protect$ f ! s& & m\nds deposit bo? to w9dw>d & to leew>d 7,fig4 #bah c & ,fig4 #bai74 ,except :5 held up by an ob/ruction1 ! drift+ s& travels to leew>d 9 sl[ly migrat+ m\nds or ridges :i* are kn[n z dunes4 ,_! motion is due to ! w9d lift+ ! s& f ! w9dw>d side & c>ry+ x ov] ! cre/1 f :]e x slides d[n ! leew>d slope & assumes a surface :i* is ! angle ( repose ( ! mat]ial4 ,9 contra/ ) ?is ! w9dw>d slope is notably gradual1 be+ %ap$ 9 con=mity to ! w9d curr5ts4 ,illu/ration3 ,,fig4 #bai4--,s& accumulat+ bo? to w9dw>d & to leew>d ( a firm & imp5etrable ob/ruction4 ,! w9d comes f ! left 7aft] a photograph by ,ba/974 ,! dunes :i* are rais$ ^u sea%ores1 l ^? ( ! des]t1 are con/antly migrat+1 ^? ^u ! %ores ( ! ,nor? ,sea at ! av]age rate ( ab\t tw5ty feet p] ye>4 ,rel5tlessly !y advance1 & despite all attempts to halt !m1 h _m times ov]:elm$ ! villages along ! coa/4 ,^u ! great b>ri] bea* kn[n z ! ,kuris*e ,nehrung1 on ! s\!a/]n %ore ( ! ,baltic ,sea1 su* a burial ( villages has m ?an once occurr$1 b z 9 ! c\rse ( "t fur!r migration ( ! dune has proce$$1 ! ru9s ( ! buri$ villages h be5 exhum$ by ?is natural excavat+ process 7,fig4 #bbj74 ,illu/ration3 ,,fig4 #bbj4--,successive diagrams to %[ h[ ! t[n ( ,kunz5 0 buri$1 & subsequ5tly exhum$ 9 ! cont9u$ migration ( a great dune ^u ! ,kuris*e ,nehrung 7aft] ,behr5dt74 ,,plate #g4 ,illu/ration3 ,a4 ,ranges ( dunes ^u ! m>g9 ( ! ,colorado ,des]t 7aft] ,m5d5hall74 ,illu/ration3 ,b4 ,s& dunes encroa*+ ^u ! oasis ( ,w$ ,s\f4 ,alg]ia 7aft] ,t4 ,h4 ,ke>ney74 ,! =ms ( dunes4--,! =ms assum$ by dunes are dep5d5t to a v l>ge ext5t ^u ! /r5g? ( ! w9d & ! available supply ( s&4 ,) small quantities ( s& & ) mod]ate w9ds1 sickle-%ap$ dunes kn[n z b>*ans 7,fig4 #bba7 are =m$1 ^: convex & flatt] slopes are t[>d ! w9d & ^: /eep concave leew>d slopes are ma9ta9$ at ! angle ( repose4 ,! b>*an is %ap$ by ! w9d go+ bo? ov] & ar\nd ! dune1 con/antly remov+ s& f ! w9dw>d side & deposit+ x to leew>d4 ,) l>g] supplies ( s& & w9ds :i* are n too viol5t a s]ies ( b>*ans is built up1 & ^! are arrang$ transv]sely to ! w9d direction 7,fig4 #bbb b74 ,if ! w9ds are m viol5t1 ! m9or depressions 9 ! cre/s ( ! dunes become w9d *annels1 & ! s& is !n trail$ out along !m until ! arrangem5t ( ! ridges is p>allel to ! w9d 7,fig4 #bbb c74 ,! surfaces ( dunes are g5]ally m>k$ by beautiful ripples 9 ! s&1 :i*1 se5 f a little di/ance1 may give ! appe>ance ( wat]$ silk 7plate #g ,a74 ,illu/ration3 ,,fig4 #bba4--,view ( des]t b>*ans 7aft] ,haug74 ,illu/ration3 ,,fig4 #bbb4--;,diagrams to %[ ! relation%ips 9 =m & 9 ori5tation ( dunes to ! supply ( s& & to ! /r5g? ( ! w9d4 a1 b>*ans =m$ by small supplies ( s& & mod]ate w9ds2 b1 transv]se dune ridges1 =m$ :5 supply ( s& is l>ge & w9ds are mod]ate2 c1 dune ridges =m$ ) l>ge s& supply & viol5t w9ds 7aft] ,wal!r & ,corni%74 ,"u normal conditions dunes are n /ation>y b cont9ue to w&] ) ! prevail+ w9ds until !y h rea*$ ! out] edge ( ! zone ( vegetation ne> ! base ( ! foo?ills at ! m>g9 ( ! des]t4 ,"h ! grasses & o!r des]t plants arre/ ! fir/ s& gra9s t rea* !m1 & !y cont9ue to gr[ high] z ! s&s accumulate4 ,"s ( ! des]t plants1 l ! yuccas1 h s adapt$ !mselves to des]t conditions t !y may gr[ upw>d ) ! s& = _m feet & s keep _! cr[ns above its surface4 ,! cl\dbur/ 9 ! des]t4--,su* cl\ds z ent] ! des]t ?r\gh its m\nta9 ramp>ts1 & ^? d]iv$ f evaporation f ! hot des]t soil1 usually precipitate _! moi/ure be=e pass+ out ( ! bas94 ,above ! highly heat$ floor ! heavy ra9 cl\ds are unable to drop _! burd54 ,! ra9 c sometimes be se5 desc5d+1 b long be=e x has rea*$ ! gr\nd x has aga9 pass$ into vapor1 & ?r\gh repetition ( ?is process ! cl\ds become s *>g$ ) moi/ure t :5 !y enc\nt] a m\nta9 wall & are ?us =c$ to rise1 !re is a sudd5 d[np\r n equal$ 9 ! humid regions4 ,des]t ra9s are r>e1 b viol5t beyond comp>ison4 ,(t5 = a ye> or m !re is no ra9fall ^u ! loose s& or por\s clay1 & ! few plants :i* survive mu/ pu% _! roots deep d[n until !y h rea*$ ! zone ( gr\nd wat]4 ,:5 ! cl\ds bur/1 ea* small caon or w$ 7pl4 wadi7 )9 ! m\nta9 wall is quickly occupi$ by a swoll5 curr5t :i* c>ries a ?ick pa/e ( s$im5t & dr[ns ev]y?+ be=e x4 ,ere x has fl[$ a mile1 x may be t ! wat] has disappe>$ entirely1 leav+ a lay] ( mud & s& :i* rapidly dries out ) ! reappe>ance ( ! sun4 ,illu/ration3 ,,fig4 #bbc4--;,ideal section across ! ris+ m\nta9 wall surr\nd+ a des]t & a "p ( ! neighbor+ slope 7aft] ,r4 ,w4 ,pumpelly74 ,z ! m\nta9s ^u seacoa/s are g5]ally ris+ ) ref]5ce to ! neighbor+ sea bottom1 s ! m\nta9s :i* hem 9 ! des]ts are g5]ally gr[+ upw>d ) ref]5ce to ! inclos$ des]t floor4 ,! m>g9al dislocations :i* sep>ate ! two are (t5 9 evid5ce at ! foot ( ! /eep slope 7,fig4 #bbc71 & ^! may ev5 appe> z visible e>?quake faults to indicate t ! uplift is m accel]at$ ?an ! deposition along ! m\nta9 front4 ,illu/ration3 ,,fig4 #bbd4--;,dry delta or alluvial fan at ! foot ( a m\nta9 range ^u ! bord]s ( a des]t4 ,! zone ( ! dw9dl+ riv]4--,! rapid uplift s g5]ally *>act]i/ic ( des]t m>g9s gives to ! torr5tial /reams :i* develop aft] ea* cl\dbur/ su* an unusual velocity t :5 !y em]ge f ! m\nta9 valleys on to ! des]t floor1 ! curr5t is sudd5ly *eck$ & ! burd5 ( s$im5t 9 l>ge "p deposit$ at ! m\? ( ! valley s z to =m a co>se delta deposit :i* is describ$ z a dry delta 7,fig4 #bbd74 ,dep5d5t ^u its /eepness ( slope1 ?is delta is v>i\sly ref]r$ to z an alluvial fan or apron1 or z an alluvial cone4 ,ov] ! conical slopes ( ! delta surface ! /ream is brok5 up into num]\s di/ribut>ies :i* divide & subdivide z d ! roots ( a tree4 ,9 ! ,mohamm$an c\ntries describ$ z wadi1 ^! di/ribut>ies ^u dry deltas are on ! ,pacific coa/ ( ! ,unit$ ,/ates ref]r$ to z 8wa%es0 7,fig4 #bbe74 ,illu/ration3 ,,fig4 #bbe4--,map ( ! di/ribut>ies ( neighbor+ /reams :i* em]ge at ! we/]n base ( ! ,si]ra ,nevadas 9 ,cali=nia 7aft] ,w4 ,d4 ,johnson74 ,fa/ los+ _! velocity aft] em]g+ f ! m\nta9s1 ! v>i\s di/ribut>ies drop fir/ ( all ! heavy b[ld]s1 !n ! l>ge pebbles & ! s&1 s t only ! f9] s& & ! silt are c>ri$ to ! m>g9 ( ! delta4 ,z !y enl>ge _! b\nd>ies1 ! neighbor+ deltas ev5tually coalesce & s =m an alluvial b5* or 8gravel pi$mont0 at ! foot ( ! range4 ,only ! l>g] /reams are able to entirely cross ?is b5* ( p>*$ deposits ) its co>sely por\s /ructure1 = ! wat] is soon suck$ up by ! ?ir/y mat]ials4 ,enc\nt]+ 9 its desc5t m clayey lay]s1 ?is wat] is conduct$ to ! surface ne> ! m>g9 ( ! b5* & may !re appe> z a l9e ( spr+s4 ,at ?is level !re develops1 !re=e1 a zone ( vegetation1 ?\gh !re is no local ra94 ,! alluvial b5* gr[s upw>d by accretion ( lay]s :i* are ?icke/ at ! m\nta9 end1 s t ! /eepness ( ! b5* increases ) "t4 ,erosion 9 & ab\t ! des]t4--,! viol5t cl\dbur/ t is *>act]i/ic ( ! arid l&s is a mo/ pot5t ag5t 9 model+ ! surface ( ! gr\nd :]ev] ! rock mat]ials are n too firmly coh]5t4 ,"u ! da% ( ! ra9 a peculi> type ( 8bad l&0 topography is develop$ 7plate #e ,b & ,fig4 #bbf74 ,su* a ra9-cut surface is a v]itable maze ( alt]nat+ gully & ridge1 a c\ntry wor?less = agricultural purposes & (f]+ ! greate/ difficulty 9 ! way ( p5etrat+ x4 ,:5 compos$ ( /iff clay ) scatt]$ pebbles & b[ld]s1 ! effect ( ! 8ra9 erosion0 is to fa%ion /eep clay pill>s ea* capp$ by a pebble & describ$ z 8demoiselles0 7,fig4 #bbf74 ,illu/ration3 ,,fig4 #bbf4--;,a gr\p ( 8demoiselles0 9 ! 8bad l&s0 7aft] a photograph by ,fairbanks74 ,beh9d ! m\nta9 front ! valleys out ( :i* ! torr5ts are dis*>g$ are usually %ort ) /eep side walls & a relatively flat bottom1 end+ headw>d 9 an amphi!at] ) precipit\s walls 7,fig4 #bbg74 ,9 ! we/]n ,unit$ ,/ates su* valleys are ref]r$ to z 8box caons01 b 9 ,mohamm$an c\ntries ! "n 8w$0 applies to ! riv] valley )9 ! m\nta9s & to ! di/ribut>ies z well4 ,*>act]i/ic features ( ! arid l&s4--,x is *>act]i/ic ( erosion & deposition )9 humid regions t all outl9es become s(t5$ into fl[+ curves1 due to ! protective mat ( vegetation4 ,9 arid l&s ^? massive rocks :i* are )\t /ructural planes ( sep>ation1 p>tly z a consequ5ce ( exfoliation1 develop broad domes :i* are project$ ^u ! horizon z great semicircles1 brok5 9 half x may be by displacem5t4 ,! same massive rocks :]e int]sect$ by v]tical jo9t planes yield1 on ! contr>y1 %>p granite ne$les l ^? ( ,h>ney ,peak 7plate #h ,a74 ,simil>ly1 s*i/ose or b$d$ rocks1 :5 tilt$ at a high angle1 may yield =ms :i* are almo/ id5tical4 ,examples ( su* ne$les are f\nd 9 ! ,g>d5 ( ! ,gods 9 ,colorado4 ,at l[] levels1 :]e ! fly+ s& becomes effective z an erod+ ag5t1 flat b$d$ rocks become et*$ into %elves & cornices1 & if int]sect$ by jo9ts1 ! %elves & cornices are trans=m$ into gr\ps ( ca/ellat$ t[]s & p9nacles ( a high degree ( ornam5tation4 ,^! fanta/ic erosion remnants are usually ref]r$ to z 8*imneys0 & may be se5 9 numb]s 9 ! bad l&s ( ,dakota1 z !y may 9 ,colorado ei!r 9 ,monum5t ,p>k or 9 ! new ,monoli?ic ,national ,p>k 7plate #h ,b74 ,illu/ration3 ,,fig4 #bbg4--;,amphi!at] at ! head ( ! ,w$ ,b5i ,sur 7aft] ,wal!r74 ,:]e w9d erosion plays a small] rle 9 ! sculpture1 b :]e aft] an uplift a riv] has made its way1 horizontally b$d$ rocks are apt to be c>v$ into broad rock t]races1 n[h]e %[n ^u s gr& a scale z ab\t ! ,gr& ,caon ( ! ,colorado4 ,ea* h>d] lay] has "h produc$ a floor or t]race :i* ends 9 a v]tical esc>pm5t1 & ?is is sep>at$ f ! next l[] lay] ( m resi/ant rock by a slope ( talus :i* l>gely hides ! s(t] int]m$iate b$s4 ,! great ,des]t ( ,sah>a is %ap$ 9 a s]ies ( rock t]races or /eppes :i* desc5d t[>d ! int]ior ( ! bas94 ,a s+le h>d] lay] ( resi/ant rock comes (t5 to =m ! flat capp+ ( a plateau1 & is !n kn[n z a mesa1 or table m\nta94 ,along its front1 deta*$ outli]s usually /& l s5t9els be=e ! l>g] mass1 & accord+ to _! relative proportions1 ^! are ref]r$ to ei!r z small mesas or z ! small] buttes 7,fig4 #bbh74 ,illu/ration3 ,,fig4 #bbh4--,mesa & outly+ butte 9 ! ,leucite ,hills ( ,wyom+ 7aft] ,:itman ,cross1 ,u4 ,s4 ,g4 ,s474 ,! w> ( dune & oasis4--,9 e des]t ! deposits are arrang$ 9 consecutive belts or zones :i* are alt]nately ! "w ( w9d & wat]4 ,surr\nd+ ! des]t & ^u ! flanks ( ! m\nta9 wall !re is f\nd 7#a7 ! deposit ( loess d]iv$ f ! du/ t is c>ri$ out ( ! des]t by ! w9d4 ,imm$iately )9 ! des]t bord] at ! base ( ! m\nta9s is 7#b7 ! zone ( ! dw9dl+ riv] ) its slop+ b5* ( co>se rubble & gravel4 ,illu/ration3 ,,fig4 #bbi4--;,flat-bottom$ bas9 sep>at+ dunes--bajir or takyr 7aft] ,ellswor? ,hunt+ton74 ,next 9 ord] is 7#c7 ! belt ( ! fly+ s&1 a zone ( dune ridges (t5 sep>at$ by n>r[1 flat-bottom$ bas9s 7,fig4 #bbi7 into :i* ! /ronge/ /reams br+ ! f9] s&s & silt f ! m\nta9s4 ,la/ly1 !re is 7#d7 ! c5tral s9k or s9ks1 into :i* all wat] n at once absorb$ )9 ! zone ( alluviation or 9 ! zone ( dunes is f9ally collect$4 ,"h are ! true lacu/r9e deposits ( clay & sep>at$ salts 7,fig4 #bcj & ,fig4 #bjg1 p4 #bja74 ,! lake deposits fill 9 all ! orig9al irregul>ities ( ! des]t floor1 out ( :i* ! tops ( isolat$ ranges ( m\nta9s n[ project l isl&s out ( ! surface ( ! sea4 ,! sev]al zones ( deposits 9 _! ord] f ! m>g9 to ! c5t] ( ! des]t are giv5 s*ematically 9 ,fig4 #bca4 ,,plate #h4 ,illu/ration3 ,a4 ,! granite ne$les ( ,h>ney ,peak 9 ! ,black ,hills ( ,s\? ,dakota 7aft] ,d>ton74 ,illu/ration3 ,b4 ,ca/ellat$ erosion *imneys 9 ,el ,cobra ,caon1 ,new ,mexico4 7,photograph by ,e4 ,c4 ,case47 ,illu/ration3 ,,fig4 #bcj4--;,bill[y surface ( ! salt cru/ on ! c5tral s9k 9 ! ,lop ,des]t ( c5tral ,asia 7aft] ,ellswor? ,hunt+ton74 ,! zone ( vegetation1 z already /at$1 lies ne> ! foot ( ! alluvial b5*1 s t "h are f\nd ! oases ab\t :i* h clu/]$ ! cities ( ! des]t f ! e>lie/ records ( antiquity until n[4 ,j )\t ! l9e ( oases is ! wall ( dunes held back f fur!r advance only by ! vegetation :i* 9 turn is dep5d5t ^u ! ra9s 9 ! neighbor+ m\nta9s4 ,) e dim9ution 9 ! wat] supply1 ! dunes advance & encroa* ^u ! oases 7plate #g ,b72 :ile ) e consid]able increase 9 ?is supply ( moi/ure ! alluvial b5* advances ov] ! dunes & acquires a /rip ( _! t]ritory4 ,?us ) v>y+ =tunes a w> is cont9ually wag$ betwe5 ! )]+ riv] & ! fly+ s&1 & ! alt]nations ( climate are lat] record$ 9 ! dovetail+ toge!r ( ! eolian & alluvial deposits at _! common junction 7,fig4 #bca74 ,illu/ration3 ,,fig4 #bca4--,s*ematic diagram to %[ ! zones ( deposition 9 _! ord] f ! m>g9 to ! c5t] ( a des]t4 ,illu/ration3 ,,fig4 #bcb4--,m\nds ^u ! site ( ! buri$ city ( ,nippur 7aft] ! ca/ by ,muret74 ,9 addition to ! small] p]iodic alt]nations ( pluvial & int]pluvial climate--! 8pulse ( ,asia0--! record ( ! ,asiatic des]ts indicates a progressive desiccation ( ! entire region1 :i* has n[ giv5 ! victory to ! dune4 ,! anci5t hi/ory ( ! cities ( ! pla9s supplies ! records ( _m t h be5 buri$ 9 ! dunes4 ,to-day1 :]e once 7 prosp]\s cities1 no?+ is to be se5 at ! surface b a gr\p ( m\nds 7,fig4 #bcb74 ,exhum$ aft] mu* pa9/ak+ labor1 ! walls & palaces ( ^! anci5t cities h once m be5 br\ght to ! light ( day1 & mu* has ?us be5 le>n$ ( ! civilization ( ^! e>ly times 7,fig4 #bcc74 ,q rec5tly ! m\nds :i* cov] betwe5 "o & two hundr$ buri$ villages h be5 f\nd ^u ! bord]s ( ! ,t>im bas9 ( c5tral ,asia1 :]e !y 7 lo/ to hi/ory :5 !y 7 ov]:elm$ 9 ! e>ly c5turies ( ! ,*ri/ian ,era4 ,illu/ration3 ,,fig4 #bcc4--;,exhum$ /ructures 9 ! buri$ city ( ,nippur 7aft] ,hilpre*t74 ,! orig9 ( ! high pla9s :i* front ! ,rocky ,m\nta9s4--,to ! ea/w>d ( ! great backbone ( ! ,nor? ,am]ican cont95t /ret*es a va/ pla9 g5tly incl9$ away f ! range & g5]ally kn[n z ! ,high ,pla9s region 7plate #i74 ,! t\ri/ :o travels we/w>d by tra9 asc5ds ?is slope s gradually t :5 he has rea*$ ! m\nta9 front x is difficult to realize t he has climb$ to an altitude ( five ?\s& feet above ! level ( ! sea4 ,t he has also pass$ ?r\gh sev]al climatic zones--a humid1 a semi>id1 & an arid--& has n[ ent]$ a semi>id di/rict1 is m easily appreciat$ f /udy ( ! vegetation 7,fig4 #bcd74 ,! surface ( ! ,high ,pla9s1 :]e n cut into by riv]s1 is rem>kably ev51 s t x might be comp>$ to ! quiet surface ( a great lake4 ,illu/ration3 ,,fig4 #bcd4--,section across ! ,high ,pla9s1 %[+ ! position ( ! t]race & ! climatic zones above x 7aft] ,w4 ,d4 ,johnson74 ,! mat]ials :i* compose ! surface v5e] ( ^! pla9s are co>se conglom]ates1 gravels1 & s&s1 & ! s-call$ 8mort> b$s01 :i* are no?+ b s&s cem5t$ into s&/one by c>bonate ( lime4 ,! pebbles 9 all ^! deposits are f>-travel$ & appe> to h be5 d]iv$ f erosion ( ^? cry/all9e rocks :i* compose ! ea/]n front ( ! ,rocky ,m\nta9s4 ,^! diff]5t mat]ials are n arrang$ 9 /rictly p>allel b$s1 z are ! deposits ( a lake or sea2 b ! b$s are made up ( long ?reads ( l5ticul> cross section :i* are int]lac$ 9 ! mo/ intricate fa%ion & :i* ext5d d[n ! slope1 or outw>d f ! m\nta9 front 7,fig4 #bce74 ,x is ?us %[n t ! ,high ,pla9s are a b5* or pla9 ( alluviation =m$ at ! front ( ! ,rocky ,m\nta9s dur+ an e>li] s]ies ( pluvial p]iods1 & t subsequ5t uplift has produc$ ! mod]n riv] valleys :i* are cut out ( ! pla94 ,! plexus ( long ?reads ( ! co>s] mat]ials are ! c\rses ( dw9dl+ riv]s :i* int]lac$ ov] ! =m] pla91 & :i* 9 "t 7 buri$ "u o!r *annel deposits ( ! same nature b 9 diff]5t positions 7,fig4 #bcf74 ,! pluvial p]iods 9 :i* ?is b5* 0 =m$ produc$ 9 o!r latitudes ! great cont95tal glaci]s :i* wr\ght su* m>vel\s *anges 9 nor!rn ,nor? ,am]ica & 9 nor!rn ,europe4 ,illu/ration3 ,,fig4 #bce4--,section across ! great l5ticul> ?reads ( alluvial deposits :i* compose ! v5e] ( ! ,high ,pla9s 7aft] ,w4 ,d4 ,johnson74 ,illu/ration3 ,,fig4 #bcf4--;,di/ribut>ies ( ! foo?ills sup]impos$ ^u an e>li] s]ies 7aft] ,w4 ,d4 ,johnson74 ,"* pr(iles4--,9 contra/ ) ! pr(iles 9 ! l&scapes ( humid regions 7see ,fig4 #ahg1 p4 #agg71 ^? ( arid l&s are m>k$ by /raight] elem5ts 7,fig4 #bcg74 ,almo/ ! only exception ( importance is furni%$ by ! domes ( massive granite monoli?s1 :i* are sometimes brok5 9 half by great displacem5ts4 ,bel[ ! horizon ! second>y l9es 9 ! l&scape betray ! same /raightness ( ! compon5t elem5ts by ! gabl$ slopes ( talus :i* are _m times repeat$ s z almo/ to reproduce ! l9es 9 a h\se ( c>ds1 s9ce ! slop+ l9es are ma9ta9$ at ! angle ( repose ( ! mat]ials 7,fig4 #dhb1 p4 #ddc74 ,:]ev] ! waves ( des]t lakes h made an attack ^u ! rocks & h retir$ ! project+ spurs1 o!r gables *>act]iz$ by slightly diff]5t slopes are introduc$ into ! l&scape4 ,illu/ration3 ,,fig4 #bcg4--;,"* pr(iles 9 ! l&scapes ( arid l&s4 ,,plate #i4 ,illu/ration3 ,,! ,,high ,,pla9s ,,read+ ,,ref]5ces ,,= ,,*apt]s ,,xv ,,& ,,xvi ,g5]al3-- ,,johannes ,,wal!r4 ,das ,gesetz d] ,w/5bildung 9 ,geg5w>t und ,vorzeit4 ,b]l91 #aijj1 pp4 #age1 _m plates4 7,?is extremely valuable "w is n[ out ( pr9t1 b bo? a revis$ edition & an ,engli% translation are promis$ = #aiab47 ,,siegfri$ ,,pass>ge4 ,die ,kalih>i4 ,b]l91 #aijd1 pp4 #ffb4 ,w4 ,m4 ,,davis4 ,! ,geographic ,cycle 9 an ,arid ,climate1 ,j\r4 ,geol41 vol4 #ac1 #aije1 pp4 #cha-djg4 ,,ellswor? ,,hunt+ton4 ,! ,pulse ( ,asia4 ,new ,york & ,bo/on1 #aijg1 pp4 #dae4 ,,sv5 ,,h$94 ,sci5tific ,results ( a ,j\rney ?r\gh ,c5tral ,asia1 #ahii-aijj4 ,/ockholm1 #aijd-aije1 vols4 #a & #b1 pp4 #ebc & #gag1 pls4 #ef & #gf4 ,,joseph ,,b>rell4 ,relative ,geological ,importance ( ,cont95tal1 ,littoral & ,m>9e ,s$im5tation1 ,j\r4 ,geol41 vol4 #ad1 #aijf1 pp4 #caf-cef1 #dbi-deg1 #ebd-efh4 ,e4 ,f4 ,,gauti]4 tudes sah>i5nes1 ,ann4 de ,gogr41 vol4 #af1 #aijg1 pp4 #df-fi1 #aag-ach4 ,! self-regi/]+ gauge ( pa/ climates3-- ,g4 ,k4 ,,gilb]t4 ,lake ,bonneville1 ,mon4 ,i1 ,u4 ,s4 ,geol4 ,surv41 ,*apt] vi1 pp4 #bad-cah4 ,t4 ,f4 ,,jamieson4 ,! ,inl& ,seas & ,salt ,lakes ( ! ,glacial ,p]iod1 ,geol4 ,mag4 decade ,,iii1 vol4 #b1 #ahhe1 pp4 #aic-bjj4 ,j4 ,e4 ,,talmage4 ,! ,great ,salt ,lake1 ,pres5t & ,pa/4 ,salt ,lake ,city1 #aijj1 pp4 #aaf1 plates4 ,e4 ,,hunt+ton4 ,"s ,*>act]i/ics ( ! ,glacial ,p]iod 9 ,non-glaciat$ ,regions1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ah1 #aijg1 pp4 #cea-chh1 pls4 #ca-ci4 ,t4 ,c4 ,,*amb]l94 ,! ,future ,habitability ( ! ,e>?1 ,rept4 ,smi?son4 ,in/41 #aiaj1 pp4 #cga-chi4 ,! r$ & br[n des]t v>ni%3-- ,i4 ,c4 ,,russell4 ,subarial ,decay ( ,rocks & ,orig9 ( ! ,r$ ,color ( ,c]ta9 ,=mations4 ,bull4 #eb1 ,u4 ,s4 ,geol4 ,surv41 #ahhi1 pp4 #fe1 pls4 #e4 ,erosion 9 ! des]t3-- ,j4 ,a4 ,,udd54 ,erosion1 ,transportation1 & ,s$im5tation p]=m$ by ! ,atmosph]e1 ,j\r4 ,geol41 vol4 #b1 #ahid1 pp4 #cah-cca4 ,s4 ,,pass>ge4 ,die pfann5frmig5 ,hohl=m5 d] sdafrikanis*5 ,/epp51 ,pet4 ,mitt41 vol4 #eg1 #aiaa1 pp4 #eg-fa1 #acj-ace4 ,! du/ c>ri$ out ( ! des]t3-- ,f4 ,,von ,,ri*t(54 ,*9a1 ,ergebnisse eig5e ,reis5 und d>auf gegrndet5 ,/udi51 ,b]l91 #ahgg1 vol4 #a1 pp4 #ef-abe4 ,e4 ,,hilg>d4 ,! ,loess ( ! ,mississippi ,valley1 ,am4 ,j\r4 ,sci41 7#c71 vol4 #ah1 #ahgi1 pp4 #ajf-aab4 ,t4 ,c4 ,,*amb]l9 & ,r4 ,d4 ,,salisbury4 ,prelim9>y ,pap] on ! ,driftless ,area ( ! ,upp] ,mississippi ,valley1 #f? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #bgh-cjg4 ,e4 ,e4 ,,free4 ,! movem5t ( soil mat]ial by ! w9d1 ) a bibliography ( eolian geology by ,s4 ,c4 ,/untz & ,e4 ,e4 ,free1 ,bull4 #fh1 ,u4 ,s4 ,bureau ( ,soils1 #aiaa1 pp4 #bgb1 pls4 #e4 ,m4 ,,neumayr4 ,erdges*i*te1 vol4 #a1 pp4 #eaj-ead4 ,e4 ,,de ,,m>tonne4 ,gographie physique1 pp4 #ffc-ffh4 ,dunes3-- ,,vaughan ,,corni%4 ,on ! ,=mation ( ,s&-dunes1 ,geogr4 ,j\r41 vol4 #i1 #ahig1 pp4 #bgh-cji 7a mo/ important pap]74 ,f4 ,,solg] & ,o!rs4 ,dn5bu*4 ,enke1 ,/uttg>t1 #aiaj1 pp4 #cgc4 ,! zone ( ! dw9dl+ riv]3-- ,e4 ,,hunt+ton4 ,! ,bord] ,belts ( ! ,t>im ,bas91 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #ch1 #aijf1 pp4 #ia-if2 ,! ,pulse ( ,asia1 pp4 #baj-bbb1 #bfb-bgi4 ,! w> ( dune & oasis3-- ,r4 ,,pumpelly4 ,explorations 9 ,turke/an1 ,exp$ition ( #aijd1 etc41 ,pub4 #gc1 ,c>neg4 ,in/41 ,wa%+ton1 vol4 #a1 pp4 #a-ac4 ,e4 ,,hunt+ton4 ,! ,oasis ( ,kh>ga1 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #db4 #aiaj1 pp4 #fda-ffa4 ,,?4 ,h4 ,,ke>ney4 ,! ,c\ntry ( ! ,ant ,m51 ,nat4 ,geogr4 ,mag41 vol4 #bb1 #aiaa1 pp4 #cfg-chb4 ,features ( ! arid l&s3-- ,c4 ,e4 ,,dutton4 ,t]ti>y ,hi/ory ( ! ,gr& ,caon ,di/rict1 ) ,atlas1 ,mon4 ,,ii1 ,u4 ,s4 ,geol4 ,surv41 #ahhb1 pp4 #bfd1 pls4 #db1 maps #bc4 ,g4 ,,swe9fur?4 ,map ,%eets ( ! ,ea/]n ,egyptian ,des]t4 ,b]l91 #aija-aijb1 #h %eets4 ,! orig9 ( ! high pla9s3-- ,w4 ,d4 ,,johnson4 ,! ,high ,pla9s & _! ,utilization1 #ba/ ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 iv1 #aija1 pp4 #fja-gda4 ,,*apt] ,,xvii ,,repeat+ ,,patt]ns ,,9 ,,! ,,e>? ,,relief ,! wea!r+ processes "u control ( ! fracture sy/em4--,9 an e>li] *apt] x 0 le>n$ t ! rocks :i* compose ! e>?'s surface %ell are int]sect$ by a sy/em ( jo9t fractures :i* 9 little-di/urb$ areas divide ! surface b$s into ne>ly squ>e p]p5dicul> prisms 7,fig4 #cf1 p4 #ee71 m or less modifi$ by additional diagonal jo9ts1 & (t5 also by m disord]ly fractures4 ,?r\gh\t l>ge areas ^! fractures may ma9ta9 ne>ly con/ant directions1 ?\gh ei!r "o or m ( ! ma/] s]ies may be locally abs5t4 ,?is di/9ctive ar*itecture ( ! surface %ell ( ! li?osph]e has ex]cis$ its influ5ce ^u ! v>i\s wea!r+ processes1 z x has also ^u ! activities ( runn+ wat] & ( o!r less common transport+ ag5cies at ! surface4 ,)9 high latitudes1 :]e fro/ action is ! dom9ant wea!r+ process1 ! wat]1 by ins9uat+ itself along ! jo9ts & ?r\gh repeat$ freez+s1 has brok5 d[n ! rock 9 ! imm$iate neighborhood ( ^! fractures1 & s has impress$ ^u ! surface an image ( ! und]ly+ patt]n ( /ructure l9es 7plate #aj ,a74 ,9 mu* l[] latitudes & 9 regions ( insuffici5t ra9fall1 ! same /ructures are impress$ ^u ! relief1 b by o!r wea!r+ processes4 ,9 ! case ( ! less coh]5t deposits 9 ^! prov9ces1 ! initial =ms ( _! erosional surface h sometimes be5 det]m9$ by ! da% ( ra9 f ! sudd5 cl\dbur/4 ,?us ! 8bad l&s0 may h _! initial gullies direct$ & spac$ 9 con=mity ) ! und]ly+ jo9t /ructures 7,fig4 #bch74 ,illu/ration3 ,,fig4 #bch4--,ra9 sculptur+ "u control by jo9ts4 ,coa/ ( s\!rn ,cali=nia 7aft] a photograph by ,fairbanks74 ,9 su* portions ( ! temp]ate regions z are favor$ by a humid climate1 ! mat ( vegetation holds d[n a lay] ( soil1 & mat & soil 9 cop]ation are effective 9 prev5t+ any su* l>ge measure ( fro/work z is *>act]i/ic ( ! subpol> regions or ( high levels 9 ! arid l&s4 ,9 humid regions ! rocks become a prey especially to ! processes ( solution & accompany+ *emical decomposition1 & ^! processes1 al?\gh guid$ by ! c\rse ( ! p]colat+ gr\nd wat] along ! fracture planes1 d n af=d su* /rik+ examples ( ! control ( surface relief4 ,^? lime/ones :i* sl[ly pass into solution 9 ! p]colat+ wat] d1 h[ev]1 q g5]ally indicate a localization ( ! solution along ! jo9t *annels 7,fig4 #bci & plate #f ,b74 ,?\gh 9 o!r rocks n s app>5t1 yet solutions g5]ally take _! c\rses along ! same *annels1 & ^u !m is localiz$ ! developm5t ( ! newly =m$ hydrat$ & c>bonate m9]als1 z is well illu/rat$ by ! ph5om5on ( sph]oidal wea!r+ 7,fig4 #aee1 p4 #aej74 ,illu/ration3 ,,fig4 #bci4--,outcrop ( flaggy lime/one :i* %[s ! effects ( solution along neighbor+ jo9ts 9 a sagg+ ( ! upp] b$s 7aft] ,gilb]t1 ,u4 ,s4 ,g4 ,s474 ,! fracture control ( ! dra9age l9es4--,! et*+ out ( ! e>?'s ar*itectural plan 9 ! surface relief1 :i* we h se5 begun 9 ! processes ( wea!r+1 is cont9u$ aft] ! transport+ ag5ts h become effective4 ,x is (t5 easy to see t a riv] has tak5 its c\rse 9 rectangul> zigzags l ! elb[s ( a jo9t$ /ove pipe1 & t its walls are =m$ ( jo9t planes f :i* an occasional squ>$ buttress projects into ! *annel4 ,?is /ructure is r5d]$ 9 ! plan ( ! ,abisko ,caon ( nor!rn ,lapl& 7,fig4 #bdj74 ,we are lat] to le>n t ano!r great transport+ ag5t1 ! wat] wave1 makes a selective attack ^u ! li?osph]e along ! fractures ( ! jo9t sy/em 7,fig4 #bej1 p4 #bcc & ,fig4 #bed1 p4 #bce74 ,illu/ration3 ,,fig4 #bdj4--,map ( ! jo9t-controll$ ,abisko ,caon 9 nor!rn ,lapl& 7aft] ,otto ,sjgr574 ,:]e ! scale ( ! example is l>ge1 z 9 ! cases :i* h be5 above cit$1 ! actual position & directions ( ! jo9t wall are easily comp>$ ) ! ne>-by elem5ts ( ! riv]'s c\rse1 s t ! connection ( ! dra9age l9es ) ! und]ly+ /ructure is at once app>5t4 ,9 _m examples :]e ! scale is small1 ! evid5ce = ! controll+ influ5ce ( ! rock /ructure 9 det]m9+ ! c\rses ( /reams may be f\nd 9 ! peculi> "* ( ! dra9age plan4 ,to illu/rate3 ! c\rse ( ! ,zambesi ,riv]1 )9 ! gorge bel[ ! fam\s ,victoria ,falls1 n only makes repeat$ turn+s at a "r angle1 b its tribut>y /reams1 in/ead ( mak+ ! usual %>p angle :]e !y jo9 ! ma9 /ream1 also affect ! "r angle 9 _! junctions 7,fig4 #bda74 ,illu/ration3 ,,fig4 #bda4--,map ( ! gorge ( ! ,zambesi ,riv] bel[ ! ,victoria ,falls 7aft] ,lamplugh74 ,! repeat+ patt]n 9 dra9age networks4--,x is a *>act]i/ic ( ! jo9t sy/em t ! fractures )9 ea* s]ies are spac$ ) approximation to uni=mity4 ,if ! plan ( a dra9age sy/em has be5 regulat$ 9 con=mity ) ! ar*itecture ( ! und]ly+ rock basem5t1 ! same repeat+ rectangles ( ! ma/] jo9ts may be expect$ to appe> 9 ! l9es ( dra9age--! s-call$ dra9age network4 ,su* rectangul> patt]ns d v g5]ally appe> 9 ! dra9age network1 ?\gh !y are (t5 mask$ ^u mod]n maps by :at1 to ! geologi/1 seems imp]t95t intrusion ( ! black l9es ( ov]pr9t+ :i* indicate railways1 l9es ( highway1 & o!r culture elem5ts4 ,on riv] maps1 :i* are pr9t$ )\t culture1 ! patt]n is mu* m easily recogniz$ 7,figs4 #bdb & #bdc74 ,:]ev] ! relief is /rong1 z is ! case 9 ! ,adirondack ,m\nta9 prov9ce ( ! ,/ate ( ,new ,york1 individual hills may /& 9 relief betwe5 ! b\nd+ /reams :i* compose ! rectangul> network1 l ! squ>$ p$e/als ( monum5ts4 ,su* a type ( relief c>v$ 9 repeat+ patt]ns has be5 describ$ z 8*eck]bo>d topography40 ,illu/ration3 ,,fig4 #bdb4--;,controll$ dra9age network ( ! ,%epaug ,riv] 9 ,connecticut4 ,illu/ration3 ,,fig4 #bdc4--;,a riv] network ( repeat+ rectangul> patt]n4 ,ne> ,lake ,temiskam+1 ,ont>io 7f ! map by ! ,dom9ion ,gov]nm5t74 ,! divid+ l9es ( ! relief patt]ns--l9eam5ts4--,! repeat+ design outl9$ 9 ! riv] network ( ! ,temiskam+ di/rict 7,fig4 #bdc7 w\ld appe> 9 great] p]fection if we c\ld reproduce ! relief )\t at ! same "t obscur+ ! l9es ( dra9age2 = :]e ! patt]n is n completely clos$ by ! c\rse ( ! /ream1 !re is g5]ally f\nd ei!r a dry valley or a rav9e to complete ! design4 ,if ^! are n pres5t1 a bit ( /raight coa/ l9e1 a visible l9e ( fracture1 a zone ( fault breccia1 or ! b\nd>y l9e sep>at+ diff]5t =mations may "o or m ( !m fill 9 ! gaps ( ! p>allel /raight dra9age l9es :i* by _! int]section br+ out ! patt]n4 ,^! significant l9es ( l&scapes :i* reveal ! hidd5 ar*itecture ( ! rock basem5t are describ$ z l9eam5ts 7,fig4 #hb1 p4 #hg74 ,!y are ! "* l9es ( ! e>?'s physiognomy4 ,x is important to emphasize ! ess5tially composite expression ( ! l9eam5t4 ,at "o locality x appe>s z a dra9age l9e1 a little f>!r on x may be a l9e ( coa/2 !n1 aga91 x is a s]ies ( align$ wat]falls1 a visible fault trace1 or a rectil9e> b\nd>y betwe5 =mations2 b 9 e case x is "s surface expression ( a buri$ fracture4 ,hidd5 z !y s g5]ally are1 ! fracture l9es mu/ be se>*$ out by e means at our disposal1 if we are n to be misl$ 9 acc\nt+ = ! positions & ! attitudes ( di/urb$ rock masses4 ,z we h le>n$1 dur+ e>?quake %ocks1 z at no o!r "t1 ! surface ( ! e>? is s s5sitiz$ z to betray ! position ( its buri$ fractures4 ,z ! b\nd>ies ( orographic blocks1 c]ta9 ( ! fractures are at su* times ! seats ( especially heavy vibrations2 !y are ! seismotectonic l9es ( ! e>?quake prov9ce4 ,_m l9eam5ts are id5tical ) seismotectonic l9es1 & !y !re=e af=d a means ( to "s ext5t det]m9+ 9 advance ! l9es ( greate/ dang] f e>?quake %ock4 ,! composite repeat+ patt]ns ( ! high] ord]s4--,n only d ! l>g] jo9t blocks become impress$ ^u ! e>? relief z repeat+ diap] patt]ns1 b l>g] & /ill l>g] composite units ( ! same type may1 9 favorable di/ricts1 be f\nd to pres5t ! same *>act]s4 ,att5tion has already be5 m ?an once direct$ to ! fact t ! m p]fect & prom95t fracture planes recur among ! jo9ts ( any s]ies at m or less regul> int]vals 7,fig4 #dj1 p4 #eg1 & ,fig4 #da1 p4 #eh74 ,n[h]e1 p]haps1 is ?is l>g] ord] ( ! repeat+ patt]n m p]fectly exemplifi$ ?an 9 "s rec5t deposits 9 ! ,syrian des]t 7plate #aj ,b74 ,x is usually1 h[ev]1 9 ! old] s$im5ts t su* /ructures may be recogniz$2 z1 = example1 9 ! squ>$ t[]s & buttresses ( ! ,tyrolean ,dolomites 7,fig4 #bdd74 ,"h ! l>g] blocks appe> 9 ! ?ick b$d$ l[] =mation1 ! dolomite1 divid$ into subord9ate sections ( l>ge dim5sions2 b 9 ! ov]ly+ =mations 9 blocks ( relatively small size1 yet ) simil>ly p]fect subequal spac+4 ,illu/ration3 ,,fig4 #bdd4--,squ>$ m\nta9 masses :i* reveal a di/ribution ( ! jo9ts 9 block patt]ns ( diff]5t ord]s ( magnitude4 ,! ,pordoi range ( ! ,sella gr\p ( ! ,dolomites1 se5 f ! ,cima di ,rossi 7aft] ,mojsisovics74 ,! obs]v+ travel] :o is privileg$ to make ! j\rney by /eam]1 ?read+ its c\rse 9 & out among ! _m isl&s & sk]ries ( ! ,norwegian coa/1 w h>dly fail to be /ruck by ! rem>kable pr(iles ( mo/ ( ! l[] isl&s 7,fig4 #bde74 ,^! pr(iles are g5]ally convexly scallop$ ) a notewor?y regul>ity1 & n 9 "o unit only1 b 9 at lea/ two ) "o a multiple ( ! o!r 7,fig4 #bdf74 ,z ! /eam] passes ne> to ! isl&s1 x is discov]$ t ! small] recognizable units 9 ! isl& pr(iles are sep>at$ by widely gap+ jo9ts :i* d n1 h[ev]1 belong to ! unit s]ies1 b to a l>g] composite gr\p 7,fig4 #bdf b74 ,fro/work1 :i* dep5ds = its action ^u op5 spaces )9 ! rocks1 has "h be5 ! cause ( ! excessive wea!r+ above ! m widely gap+ jo9ts4 ,,plate #aj4 ,illu/ration3 ,a4 ,view 9 ,spitzb]g5 to illu/rate ! dis9tegration ( rock "u ! control ( jo9ts4 7,photograph by ,o4 ,hald947 ,illu/ration3 ,b4 ,composite patt]n ( ! jo9t /ructures )9 rec5t alluvial deposits4 7,photograph by ,ellswor? ,hunt+ton47 ,illu/ration3 ,,fig4 #bde4--;,isl& gr\ps ( ! ,l(ot5 ar*ipelago (f ! nor?we/ coa/ ( ,norway1 :i* reveal repeat+ patt]ns ( ! relief 9 two ord]s ( magnitude 7aft] a photograph by ,knuds574 ,illu/ration3 ,,fig4 #bdf4--;,diagrams to illu/rate ! composite pr(iles ( ! isl&s on ! ,norwegian coa/4 a1 di/ant view2 b1 ne> view1 %[+ ! individual jo9ts & ! m widely gap+ fractures b5ea? ea* sag 9 ! pr(ile4 ,high nor!rn latitudes are ?us especially favorable = reveal+ all ! details 9 ! ar*itectural patt]n ( ! li?osph]e %ell1 & we ne$ n be surpris$ t :5 ! mod]n maps ( ! ,norwegian coa/ are exam9$1 /ill l>g] repeat+ patt]ns ?an any t may be se5 9 ! field are to be made out4 ,! ,norwegian coa/ 0 long ago %[n to be a complexly fault$ region1 & ^! l>g] divisions ( ! relief patt]n1 in/ead ( be+ expla9$ z a consequ5ce solely ( selective wea!r+1 mu/ be reg>d$ z due l>gely to fault displacem5ts ( ! type repres5t$ 9 our model 7plate #d ,c74 ,yet :e!r due to displacem5ts or to ! m num]\s jo9ts1 all belong to ! same composite sy/em ( fractures express$ 9 ! relief4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xvii ,,william ,h4 ,,hobbs4 ,! ,riv] ,sy/em ( ,connecticut1 ,j\r4 ,geol41 vol4 #i1 #aija1 pp4 #dfi-dhe1 pl4 #a2 ,l9eam5ts ( ! ,atlantic ,bord] ,region1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ae1 #aijd1 pp4 #dhc-ejf1 pls4 #de-dg2 ,! ,correlation ( ,fracture ,sy/ems & ! ,evid5ces = ,planet>y ,dislocations )9 ! ,e>?'s ,cru/1 ,trans4 ,wis4 ,acad4 ,sci41 etc41 vol4 #ae1 #aije1 pp4 #ae-bi2 ,repeat+ ,patt]ns 9 ! ,relief & 9 ! ,/ructure ( ! ,l&1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #bb1 #aiaa1 pp4 #abc-agf1 pls4 #g-ac4 ,,*apt] ,,xviii ,,! ,,=ms ,,c>v$ ,,& ,,mold$ ,,by ,,waves ,! motion ( a wat] wave4--,! motions )9 a wave ^u ! surface ( a body ( wat] may be ?\ght ( 9 two diff]5t ways4 ,fir/ ( all1 !re is ! motion ( ea* p>ticle ( wat] )9 an orbit ( its own2 & !re is1 fur!r1 ! =w>d motion ( propagation ( ! wave consid]$ z a :ole4 ,illu/ration3 ,,fig4 #bdg4--;,diagram to %[ ! nature ( ! motions )9 a free wat] wave4 ,! wat] p>ticle 9 a wave has a cont9u$ motion r\nd & r\nd its orbit l t ( a horse circl+ a race c\rse1 only t "h ! track is 9 a v]tical plane1 direct$ along ! l9e ( propagation ( ! wave 7,fig4 #bdg74 ,ea* p>ticle ( wat]1 ?r\gh its friction ^u neighbor+ p>ticles1 is able to transmit its motion bo? along ! surface & d[nw>d into ! wat] bel[4 ,! =ce :i* />ts ! wat] 9 motion & develops ! wave1 is ! friction ( w9d bl[+ ov] ! wat] surface1 & ! size ( ! orbit ( ! wat] p>ticle at any po9t is proportional to ! w9d's =ce & to ! /ret* ( wat] ov] :i* x has bl[n4 ,! w9d's effect is1 !re=e1 cumulative--! wave is proportional to ! w9d's effect ^u all wat] p>ticles 9 its re>1 add$ to ! local w9d friction4 ,! size or height ( ! wave is measur$ by ! diamet] ( ! orbit ( motion ( ! surface p>ticle1 & ?is is ! diff]5ce 9 height betwe5 tr\gh & cre/4 ,! di/ance f cre/ to cre/1 or f tr\gh to tr\gh1 is call$ ! wave l5g?4 ,?\gh ! wave motion is transmitt$ d[nw>d into ! wat] !re is a cont9u$ loss ( en]gy :i* is "h n comp5sat$ by add$ w9d friction1 & s ! orbital motion gr[s small] & small]1 until at ! dep? ( ab\t a wave l5g? x has completely di$ out4 ,?is level ( no motion is call$ ! wave base4 ,9 quiet wea!r ! level ( no motion is practically at ! wat]'s surface1 & inasmu* z ! geological "w ( waves is 9 l>ge "p accompli%$ dur+ ! great /orms1 ! t]m 8wave base0 ref]s to ! l[e/ level ( wave motion at ! "t ( ! heavie/ /orms4 ,^u ! ocean ! highe/ waves t h be5 measur$ h an amplitude ( ab\t fifty feet & a wave l5g? ( ab\t six hundr$ feet4 ,free waves & break]s4--,s long z ! dep? ( ! wat] is bel[ wave base1 !re is obvi\sly no possibility ( int]f]5ce ) ! wave ?r\gh friction ^u ! bottom4 ,"u ^! conditions waves are describ$ z free waves1 & _! =ms are symmetrical except 9 s f> z _! cre/s are pull$ ov] & m or less dissipat$ 9 ! spray ( ! 8:ite caps0 at ! "t ( high w9ds4 ,illu/ration3 ,,fig4 #bdh4--;,diagram to illu/rate ! trans=mation ( a free wave into a break] z x approa*es ! %ore4 ,z a wave approa*es a %ore1 :i* g5]ally has a g5tle outw>d slop+ surface1 !re is int]pos$ 9 ! way ( a free =w>d movem5t ! friction ^u ! bottom4 ,?is friction beg9s :5 ! dep? ( wat] is less ?an wave base1 & its effect is to hold back ! wave at ! bottom4 ,c>ri$ sl[ly upw>d 9 ! wat] by ! friction ( p>ticle ^u p>ticle1 ! effect ( ?is hold+ back is a pil+ up ( ! wat]1 :i* increases ! wave height z x dim9i%es ! wave l5g?1 & also int]f]es ) wave symmetry 7,fig4 #bdh74 ,mov+ =w>d at ! top "u its in]tia ( motion & held back at ! bottom by con/antly increas+ friction1 a /rong turn+ motion or c\ple is />t$ ab\t a horizontal axis1 ! imm$iate effect ( :i* is to /eep5 ! =w>d slope ( ! wave1 & ?is cont9ues until x ov]hangs1 &1 fall+1 8breaks0 into surf4 ,su* a break+ wave is call$ a 8comb]0 or 8break]0 7plate #aa ,b74 ,,plate #aa4 ,illu/ration3 ,a4 ,ripple m>k+s )9 an anci5t s&/one 7c\rtesy ( ,u4 ,s4 ,grant74 ,illu/ration3 ,b4 ,a wave break+ z x approa*es ! %ore4 7,photograph by ,fairbanks47 ,illu/ration3 ,,fig4 #bdi4--,not*$ rock cliff cut by waves & ! fall5 blocks d]iv$ f ! cliff ?r\gh und]m9+4 ,pr(ile ,rock at ,f>well's ,po9t ne> ,madison1 ,wiscons94 ,effect ( ! break+ wave ^u a /eep rocky %ore--! not*$ cliff4--,if ! %ore rises abruptly f deep] wat]1 ! top ( ! break+ wave is hurl$ aga9/ ! cliff ) ! =ce ( a batt]+ ram4 ,dur+ /orms ! wat] ( %ore waves is *>g$ ) s&1 & ea* s& p>ticle is driv5 l a /one cutt]'s tool "u ! /roke ( 8 hamm]4 ,! effect is ?us bo? to *ip & to batt] away ! rock ( ! %ore to ! height rea*$ by ! wave1 und]m9+ x & not*+ ! rock at its base 7,fig4 #bdi74 ,:5 ! not* has be5 cut 9 ?is mann] to a suffici5t dep?1 ! ov]hang+ rock falls by its own weight 9 blocks :i* are b\nd$ by ! ev] pres5t jo9ts1 leav+ ! upp] cliff face ess5tially v]tical4 ,illu/ration3 ,,fig4 #bej4--;,a wave-cut *asm "u control by jo9ts1 coa/ ( ,ma9e 7aft] ,t>r74 ,coves1 sea ar*es1 & /acks4--,x is ! headl& :i* is mo/ expos$ to ! "w ( ! waves1 s9ce ) *ange ( w9d direction x is expos$ ^u m ?an a s+le face4 ,! /udy ( headl&s :i* h be5 cut by waves %[s t ! jo9ts )9 ! rock play a l>ge rle 9 ! %ap+ ( %ore features4 ,! attack ( ! waves "u ! direction ( ^! planes ( ready sep>ation op5s out ind5tations ( ! %ore 7,fig4 #bej7 or =ms sea caves :i*1 z !y ext5d to ! top ( ! cliff by ! process ( sapp+1 yield ! coves :i* are s common a feature ^u our rock-b\nd %ores 7,fig4 #bei1 p4 #bch74 ,) cont9uation ( ?is process1 ! caves =m$ on opposite sides ( ! headl& may be unit$ to =m a sea ar* 7,fig4 #bea74 ,illu/ration3 ,,fig4 #bea4--,! sea ar* kn[n z ! ,gr& ,ar* ^u "o ( ! ,apo/le ,isl&s 9 ,lake ,sup]ior 7aft] a photograph by ! ,detroit ,photographic ,company74 ,a lat] /age 9 ?is selective wave c>v+ "u ! control ( jo9ts is rea*$ :5 ! bridge above ! ar* has fall5 91 leav+ a deta*$ rock isl& ) precipit\s walls4 ,su* an (f%ore isl& ( rock ) precipit\s sides is kn[n z a /ack 7,fig4 #beb71 or sometimes z a 8*imney01 ?\gh ?is latt] t]m is be/ re/rict$ to o!r & simil> =ms :i* are ! product ( selective wea!r+ 7p4 #cjj74 ,illu/ration3 ,,fig4 #beb4--,/ack ne> ! %ore ( ,lake ,sup]ior4 ,:5ev] ! rock is less firmly consolidat$1 & s does n /& ^u su* /eep planes1 ! /ack is apt to h a m conical =m1 & may n be prec$$ 9 its =mation by ! developm5t ( ! sea ar* 7,fig4 #bfj1 p4 #bci74 ,9 ! rev]se case1 or :]e ! rock possesses an unusual t5acity1 ! /ack may be l>gely und]m9$ & /& support$ l a table ^u ?ick legs or pill>s ( rock 7,fig4 #bec74 ,9 ,fig4 #bed is se5 a gr\p ( /acks ^u ! coa/ ( ,cali=nia1 :i* %[ ) cle>ness ! control ( ! jo9ts 9 _! =mation1 b unlike ! m>ble ( ! ,s\? ,am]ican example ! =ms are n r\nd$1 b reta9 _! %>p angles4 ,illu/ration3 ,,fig4 #bec4--,! ,m>ble ,isl&s1 /acks 9 ,lake ,bu5os ,aires1 s\!rn ,&es 7aft] ,f4 ,p4 ,mor5o74 ,! cut rock t]race4--,:5 waves fir/ beg9 _! attack ^u a /eep1 rocky %ore1 ! l[] limit ( ! action is ne> ! wave base4 ,! action at ?is dep? is1 h[ev]1 less effici5t1 & z ! recession ( ! cliff is "o ( ! mo/ rapid ( erosional processes1 ! rock floor outside ! rec$+ cliff comes to slope gradually d[nw>d f ! cliff to a maximum dep? at ! edge ( ! t]race1 approximately equal to wave base 7,fig4 #bee74 ,?is cut t]race is ext5d$ seaw>d or lakew>d1 z ! case may be1 9 a built t]race con/ruct$ f a portion ( ! rock dbris acquir$ f ! cliff4 ,illu/ration3 ,,fig4 #bed4--,squ>$ /acks :i* reveal ! position ( ! jo9t planes :i* h controll$ 9 ! process ( c>v+ by ! waves4 ,pt4 ,bu*on1 ,cali=nia 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #bee4--;,ideal section ( a /eep rocky %ore c>v$ by waves into a not*$ cliff & cut t]race1 & ext5d$ by a built t]race4 ,! brok5 wave1 aft] ris+ ^u ! t]race "u ! in]tia ( its motion until all its en]gy has be5 dissipat$1 slides outw>d by gravity1 & ?\gh *eck$ & ov]ridd5 by succe$+ break]s1 x cont9ues its outw>d slide z ! 8und]t[0 until x rea*es ! end ( ! t]race4 ,"h x sudd5ly ent]s deep wat]1 & los+ its velocity1 drops its burd5 ( rock1 & builds ! t]race seaw>d aft] ! mann] ( con/ruction ( an embankm5t4 ,z we are to see1 ! l>g] portion ( ! wave-qu>ri$ mat]ial is div]t$ to a diff]5t qu>t]4 ,illu/ration3 ,,fig4 #bef4--,map %[+ ! outl9es ( ! ,isl& ( ,heligol& at diff]5t /ages 9 its rec5t hi/ory4 ,! p]iph]ies giv5 are 9 miles4 ,to ga9 "s conception ( ! importance ( wave cutt+ z an erod+ process1 we may consid] ! late hi/ory ( ,heligol&1 a s&/one isl& (f ! m\? ( ! ,elbe 9 ! ,nor? ,sea 7,fig4 #bef74 ,f a p]iph]y ( #abj miles1 :i* x possess$ 9 ! n9? c5tury ( ! ,*ri/ian era1 ! isl& has r$uc$ its outl9e to #de miles 9 ! f\rte5? c5tury1 #h miles 9 ! sev5te5?1 & to ab\t #c miles at ! beg9n+ ( ! tw5tie? c5tury4 ,! ,g]man gov]nm5t1 :i* rec5tly acquir$ ?is little remnant f ,engl&1 has exp5d$ l>ge sums ( money 9 an ef=t to save ?is la/ relic4 ,illu/ration3 ,,fig4 #beg4--;,cut & built t]race ) b[ld] pavem5t %ap$ by waves on a /eep %ore =m$ ( loose mat]ials4 ,! cut & built t]race on a /eep %ore ( loose mat]ials4--,9 mat]ials :i* lack ! coh]5ce ( firm rock1 no v]tical cliff c =m2 = z fa/ z und]m9$ by ! waves ! loose mat]ials slide d[n & assume a surface ( practically con/ant slope--! 8angle ( repose0 ( ! mat]ials 7,fig4 #beg74 ,! t]race bel[ ?is slop+ cliff w n diff] 9 %ape f t cut ^u a rocky %ore2 b :5ev] ! mat]ials ( ! %ore include dissem9at$ blocks too l>ge = ! waves to h&le1 !y collect ^u ! t]race ne> :]e !y h be5 exhum$1 ?us =m+ :at has be5 call$ a 8b[ld] pavem5t0 7,fig4 #beh74 ,illu/ration3 ,,fig4 #beh4--,slop+ cliff & t]race ) b[ld] pavem5t expos$ at l[ tide ^u ! %ore at ,scituate1 ,massa*usetts4 ,! edge ( ! cut & built t]race is1 z already m5tion$1 ma9ta9$ at ! dep? ( wave base4 ,if "o w /udy ! subm]g$ cont\rs ( any ( our inl& lakes1 x w be f\nd t ^! bas9s are surr\nd$ by a g5tly slop+ m>g9al %elf1--! cut & built t]race1--& t ! dep? ( ?is %elf at its out] edge is proportion$ to ! size ( ! lake4 ,^u ,lake ,m5dota at ,madison1 ,wiscons91 ! l>ge /orm waves h a l5g? ( ab\t tw5ty feet1 :i* is ! dep? ( ! out] edge ( ! %ore t]races 7,fig4 #bfg1 p4 #bdb74 ,! %elf surr\nd+ ! cont95ts has1 ) few local exceptions1 a uni=m dep? ( #ajj fa?oms1 or ab\t ! wave base ( ! heavie/ /orm waves4 ,! "w ( ! %ore curr5t4--,9 describ+ ! =mation ( ! built t]race1 x 0 /at$ t ! great] "p ( ! rock mat]ial qu>ri$ ^u headl&s by ! waves is div]t$ f ! (f%ore t]race4 ,?is div]sion is ! "w ( ! %ore curr5t produc$ by ! wave4 ,illu/ration3 ,,fig4 #bei4--,map to %[ ! nature ( ! %ore curr5t & ! =ms :i* are mold$ by x4 ,at b few places ^u a %ore w ! /orm waves beat p]p5dicul>ly1 & !n = b %ort p]iods only4 ,! brok5 wave1 z x crawls ev] m sl[ly up ! bea*1 c>ries ! s& ) x 9 a sweep+ curve1 & by ! "t gravity has put a /op to its =w>d movem5t1 x is direct$ = a brief in/ant p>allel to ! %ore4 ,soon1 h[ev]1 ! pull ( gravity ^u x has />t$ ! backw>d j\rney 9 a m direct c\rse d[n ! slope ( ! t]race2 & "h enc\nt]+ ! next succe$+ break]1 a portion ( ! wat] & ! co>s] s& p>ticles ) x are aga9 c>ri$ =w>d = a repetition ( ! zigzag j\rney4 ,?is _m times int]rupt$ movem5t ( ! s& p>ticles may be obs]v$ dur+ a high w9d ^u any s&y lee %ore4 ,! 8set0 ( ! wat] along ! %ore z a result ( its zigzag j\rney+s is describ$ z ! %ore curr5t 7,fig4 #bei71 & ! effect ^u s& di/ribution is ! same z ?\gh a /eady curr5t mov$ p>allel to ! %ore 9 ! direction ( ! av]age tr5d ( ! mov+ p>ticles4 ,! s& bea*4--,! fir/ effect ( ! %ore curr5t is to deposit "s portion ( ! s& )9 ! fir/ slight recess ^u ! %ore 9 ! lee ( ! cliff4 ,! e>li] deposits ne> ! cliff gradually =ce ! %ore curr5t f>!r f ! %ore & s lay d[n a s& selvage to ! %ore1 :i* is %ap$ 9 ! =m ( an arc or cresc5t & kn[n z a bea* 7,fig4 #bei & ,fig4 #bfj74 ,illu/ration3 ,,fig4 #bfj4--;,cresc5t-%ap$ bea* =m$ 9 ! lee ( a headl&4 ,santa ,catal9a ,isl&1 ,cali=nia 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #bfa4--;,cross section ( a bea* pebble4 ,! %+le bea*4--,) heavy /orms & an exceptional rea* ( ! waves1 ! %ore curr5ts are compet5t to move1 n ! s& alone1 b pebbles1 ! area ( ^: broad] surface may be z great z ! palm ( "o's h&4 ,su* rock fragm5ts are %ap$ by ! cont9u$ we> aga9/ _! neighbors "u ! re/less break]s1 until !y h a l5ticul> or wat*-%ap$ =m 7,fig4 #bfa74 ,su* bea* pebbles are describ$ z %+le1 & !y are usually built up into di/9ct ridges ^u ! %ore1 :i*1 "u ! fury ( ! high break]s1 may be pil$ sev]al feet above ! level ( quiet wat] 7,fig4 #bfb74 ,su* /orm bea*es h a g5tle =w>d slope grad$ by ! %ore curr5t1 b a /eep backw>d slope on ! angle ( repose4 ,mo/ /orm bea*es h be5 l>gely %ap$ by ! la/ great /orm1 su* z comes only at int]vals ( a numb] ( ye>s4 ,illu/ration3 ,,fig4 #bfb4--,/orm bea* ( co>se %+le ab\t f\r feet 9 height at ! base ( ,burnt ,bluff on ! nor!a/ %ore ( ,gre5 ,bay1 ,lake ,mi*igan4 ,b>1 spit1 & b>ri]4--,:]ev] ! %ore ^u :i* a bea* is build+ makes a sudd5 l&w>d turn at ! entrance to a bay1 ! %ore curr5ts1 by virtue ( _! in]tia ( motion1 are unable long] to foll[ ! %ore4 ,! dbris :i* !y c>ry is ?us transport$ into deep] wat] 9 a direction correspond+ to a cont9uation ( ! %ore j be=e ! po9t ( turn+ 7see ,fig4 #bei1 p4 #bch74 ,! result is ! =mation ( a b>1 :i* rises to ne> ! wat] surface & is ext5d$ across ! entrance to ! bay ?r\gh cont9u$ gr[? at its end1 aft] ! mann] ( con/ruct+ a railway embankm5t across a valley4 ,illu/ration3 ,,fig4 #bfc4--,spit ( %+le on ,au ,tra9 ,isl&1 ,lake ,sup]ior 7aft] ,gilb]t74 ,ov] ! deep] wat] ne> ! b> ! waves are at fir/ n g5]ally halt$ & brok51 z !y are ^u ! %ore1 & s ! b> does n at once build itself to ! surface1 b rema9s an invisible b> to navigation4 ,f its %orew>d end1 h[ev]1 ! waves ( ev5 mod]ate /orms are brok51 & ! b> is !re built above ! wat] surface1 :]e x appe>s z a n>r[ cape ( s& or %+le :i* gradually ?9s 9 approa*+ its apex4 ,?is feature is ! well-kn[n spit 7,fig4 #bfc7 :i*1 z x gr[s across ! entrance to ! bay1 becomes a b>ri] or b>ri] bea* 7,fig4 #bfd74 ,! cont9uation ( ! visible 9 ! usually invisible b>1 is at ! "t ( high w9ds made /rik+ly app>5t1 = ! wave base is bel[ ! cre/ ( ! b>1 & at su* times its cresc5tic c\rse beyond ! spit c be foll[$ by ! eye 9 a :ite arc ( brok5 wat]4 ,illu/ration3 ,,fig4 #bfd4--;,b>ri] bea* 9 front ( a lagoon on ,lake ,m5dota at ,madison1 ,wiscons94 ,! %all[ lagoon beh9d ! b>ri] is fill+ up & is l>gely hidd5 9 vegetation4 ,! con/ruction ( a b>ri] across ! entrance to a bay trans=ms ! latt] into a sep>ate body ( wat]1 a lagoon1 )9 :i* silt+ up & peat =mation usually lead to an e>ly ext9ction 7p4 #dbi74 ,! =mation ( b>ri]s ?us t5ds to /raight5 out ! irregul>ities ( coa/ l9es1 & op5s ! way to a natural enl>gem5t ( ! l& areas4 ,:ile ! coa/s ( ! ,unit$ ,k+dom ( ,great ,brita9 h be5 los+ "s f\r ?\s& acres ?r\gh wave erosion1 !re has be5 a ga9 by gr[? 9 quiet lagoons :i* am\nts to ne>ly sev5 times t am\nt4 ,z evid5ce ( ! /raight5+ ( ! %ore l9e :i* results f ?is process1 ! coa/ ( ! ,c>ol9as or ( ,nantucket 7,fig4 #dei7 may s]ve = illu/ration4 ,! l&-ti$ isl&4--,we h se5 t wave erosion op]ates to sep>ate small isl&s f ! headl&s1 b ! %ore curr5ts c\nt]act ?is loss to ! cont95ts by ?r[+ out b>ri]s :i* jo9 _m sep>at$ isl&s to ! ma9l&4 ,su* l&-ti$ isl&s are a common feature on _m rocky coa/s1 & ^u ! ,new ,engl& coa/ !y usually h be5 giv5 ! "n ( 8neck40 ,! long arc ( ,lynn ,bea* jo9s ! =m] isl& ( ,nahant1 ?r\gh its small] neighbor ,little ,nahant1 to ! coa/ ( ,massa*usetts4 ,a simil> l&-ti$ isl& is ,m>blehead ,neck4 ,! ,rock ( ,gibralt>1 =m]ly an isl&1 is n[ jo9$ to ,spa9 by ! l[ bea* kn[n z ! 8neutral gr\nd40 ,! ,spani% "n1 tombola1 has sometimes be5 employ$ to describe an isl& ?us connect$ to ! %ore4 ,illu/ration3 ,,fig4 #bfe4--;,cross section ( a b>ri] bea* ) lagoon 9 its re>4 ,a b>ri] s]ies4--,! cross section ( a b>ri] bea*1 l t ( a /orm bea* ^u ! %ore1 slopes g5tly ^u ! =w>d side1 & m /eeply at ! angle1 ( repose ^u ! re> or l&w>d m>g9 7,fig4 #bfe74 ,! ?9n+ w$ge ( %ore deposits :i* ! b>ri] ?r[s out to seaw>d raises ! level ( ! lake bottom 7,fig4 #bff71 & :5 coa/ irregul>ities are favorable to x1 new spits w develop ^u ! %ore outside ! e>li] "o1 & a new b>1 & 9 its turn a b>ri]1 w be f\nd outside ! initial "o1 tak+ a c\rse 9 a direction m or less p>allel to x 7,fig4 #bfg74 ,illu/ration3 ,,fig4 #bff4--;,cross section ( a s]ies ( b>ri]s & an out] b>4 ,illu/ration3 ,,fig4 #bfg4--;,=mation ( b>ri] s]ies & an out] b> 9 ,univ]sity ,bay ( ,lake ,m5dota1 at ,madison1 ,wiscons94 ,! wat] cont\r int]val is five feet1 & ! l& cont\r int]val t5 feet 7bas$ on a map by ! ,wiscons9 ,geological ,survey74 ,illu/ration3 ,,fig4 #bfh4--,s]ies ( b>ri]s at ! we/]n end ( ,lake ,sup]ior 7aft] ,gilb]t74 ,s soon z ! fir/ b>ri] is =m$1 processes are set 9 op]ation :i* t5d to trans=m ! newly =m$ lagoon into l&1 & s ) a s]ies ( b>ri]s1 a zone ( wat] lilies betwe5 ! out] b>ri] & ! b>1 a bog1 & a l& plat=m may repres5t ! successive /ages 9 ?is acquisition ( t]ritory by ! l&s4 ,a notewor?y example ( b>ri] s]ies & ext5sion ( ! l& beh9d !m1 is af=d$ by ! bay at ! we/]n end ( ,lake ,sup]ior 7,fig4 #bfh74 ,illu/ration3 ,,fig4 #bfi4--;,"* pr(iles result+ f wave action ^u %ores4 ,"* pr(iles4--,! "* pr(iles yield$ by ! "w ( waves are easy ( recognition 7,fig4 #bfi74 ,! v]tical cliff ) not* at its base is v>i$ by ! /ack ( sug>-loaf =m c>v$ 9 s(t] rocks1 or ! /eep] not*$ v>iety cut f h>d] masses4 ,sea caves & sea ar*es yield v>iations ( a curve common to ! und]cut =ms4 ,:]ev] ! mat]ials ( ! %ore are loosely consolidat$ only1 ! slop+ cliff is =m$ at ! angle ( repose ( ! mat]ials4 ,! b>ri] bea*1 ?\gh project+ b a %ort di/ance above ! waves1 %[s an unsymmetrical curve ( cross section ) ! /eep] slope t[>d ! l&4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xviii ,g4 ,k4 ,,gilb]t4 ,! ,topographic ,features ( ,lake ,%ores1 #e? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #fi-abc1 pls4 #c-bj2 ,lake ,bonneville1 ,mon4 ,i1 ,u4 ,s4 ,geol4 ,surv41 #ahij1 ,*apt]s ii-iv1 pp4 #bc-ahg4 ,,vaughan ,,corni%4 ,on ,sea ,bea*es & ,s& ,banks1 ,geogr4 ,j\r41 vol4 #aa1 #ahih1 pp4 #ebh-edc1 #fbh-feh4 ,f4 ,p4 ,,gulliv]4 ,%ore ,l9e ,topography1 ,proc4 ,am4 ,acad4 ,arts & ,sci41 vol4 #cd1 #ahii1 pp4 #adi-beh4 ,n4 ,s4 ,,%al]4 ,! ,geological ,hi/ory ( ,h>bors1 #ac? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahic1 pp4 #ic-bji4 ,,sir ,a4 ,,geikie4 ,! ,sc5]y ( ,scotl&1 #aija1 pp4 #df-hi4 ,w4 ,h4 ,,:eel]4 ,! ,sea ,coa/4 ,longmans1 ,london1 #aijb1 pp4 #a-gh4 ,g4 ,w4 ,,von ,,zahn4 ,die z]/r5de ,arbeit des ,me]es an ,/eilk/5 na* ,beoba*tung5 9 d] ,bretagne und ,norm&ie 9 d5 ,jahr5 #aijg und #aijh1 ,mitt4 d4 ,geogr4 ,ges4 ,hamb41 vol4 #bd1 #aiaj1 pp4 #aic-bhd1 pls4 #ab-bg4 ,,*apt] ,,xix ,,coa/ ,,records ,,( ,,! ,,rise ,,or ,,fall ,,( ,,! ,,l& ,! *>act]s 9 :i* ! record has be5 pres]v$4--,! peculi> =ms into :i* ! sea has et*$ & mold$ its %ores h be5 consid]$ 9 ! la/ *apt]4 ,( ^! ! m significant are ! not*$ rock cliff1 ! cut rock t]race1 ! sea cave1 ! sea ar*1 ! /ack1 & ! slop+ cliff & t]race1 among ! c>v$ features2 & ! b>ri] bea* & built t]race1 among ! mold$ =ms4 ,x is important to rememb] t ! mold$ =ms1 by ! v mann] ( _! =mation1 /& 9 a def9ite relation%ip to ! c>v$ features2 s t :5 ei!r "o has be5 9 "p effac$ & made difficult ( det]m9ation1 ! discov]y ( ! o!r 9 its correct natural position may remove all d\bt z to ! orig9 ( ! relic4 ,illu/ration3 ,,fig4 #bgj4--,! ea/ coa/ ( ,florida1 ) %ore l9e *>act]i/ic ( a rais$ coa/4 ,9 /udies ( ! *ange ( level ( ! l&1 x is cu/om>y to ref] all v>iations to ! sea level z a z]o plane ( ref]5ce4 ,x is n on ?is acc\nt necess>y to assume t ! *anges measur$ f ?is arbitr>y datum plane are ! absolute upw>d or d[nw>d oscillations :i* w\ld be measur$ f ! e>?'s c5t]2 = ! sea1 l ! l&1 has be5 subject to its *anges ( level4 ,!re ne$1 h[ev]1 be no apology = ! use ( ! sea surface z a plane ( ref]5ce2 = x is all t we h available = ! purpose1 & ! *anges 9 level1 ev5 if relative only1 are ( ! greate/ significance4 ,x is probable t 9 mo/ cases :]e ! coa/ l9e is ris+ f uplift1 "s portion ( ! sea bas9 n f> di/ant is becom+ deep5$1 s t ! visible *ange ( level is ! algebraic sum ( ! two effects4 ,ev5 coa/ l9e ! m>k ( uplift4--,x 0 e>ly po9t$ out 9 ?is volume 7p4 #aeh7 t ! floor ( ! sea 9 ! neighborhood ( ! l& pres5ts a relatively ev5 surface4 ,! c>v+ by waves1 comb9$ ) ! process ( deposition ( s$im5ts1 t5ds to fill up ! m9or irregul>ities ( surface & pres]ve only ! features ( l>g] scale1 & ^! 9 mu* s(t5$ outl9es4 ,^u ! cont95ts1 on ! contr>y1 ! runn+ wat]1 tak+ advantage ( e slight diff]5ce 9 elevation & se>*+ out ! hidd5 /ructure planes )9 ! rock1 soon et*es out a surface ( ! mo/ intricate detail4 ,! effect ( elevation ( ! sea floor into ! light ( day w !re=e be to produce an ev5 %ore l9e devoid ( h>bors 7,fig4 #bgj74 ,if ! coa/ has ris5 along visible planes ( fault+ ne> ! sea m>g91 ! coa/ l9e1 9 addition to be+ ev51 w usually be made up ( notably /raight elem5ts jo9$ to "o ano!r4 ,illu/ration3 ,,fig4 #bga4--,ragg$ coa/ l9e ( ,alaska1 ! effect ( subsid5ce4 ,a ragg$ coa/ l9e ! m>k ( subsid5ce4--,:5 9 place ( uplift a subsid5ce occurs ^u ! coa/1 ! intricately et*$ surface1 result+ f erosion b5ea? ! sky1 comes to be invad$ by ! sea along ea* tr5* & furr[1 s t a mo/ ragg$ outl9e is ! result 7,fig4 #bga74 ,su* a coa/ has _m h>bors1 :ile ! uplift$ coa/ is z rem>kable = its lack ( !m4 ,sl[ uplift ( ! coa/--! coa/al pla9 & cue/a4--,a gradual uplift ( ! coa/ is made app>5t 9 a progressive retirem5t ( ! sea across a portion ( its floor1 ?us expos+ ?is ev5 surface ( rec5t s$im5ts4 ,! =m] %ore l& w be easily recogniz$ by x's et*$ surface1 :i* w n[ come into %>p contra/ ) ! new pla94 ,x is !re=e ref]r$ to z ! oldl& & ! newly expos$ coa/al pla9 z ! newl& 7,fig4 #bgb74 ,illu/ration3 ,,fig4 #bgb4--,portion ( ,atlantic coa/al pla9 & neighbor+ oldl& ( ! ,appala*ian ,m\nta9s4 ,b ! ne>-%ore deposits ^u ! sea floor _h an initial dip or slope to seaw>d1 & ?is incl9ation has be5 increas$ 9 ! process ( uplift4 ,! /reams f ! oldl& h tr5*$ _! way across ^! deposits :ile ! %ore 0 ris+4 ,b ! process be+ a sl[ "o1 deposits h =m$ ^u ! seaw>d side ( ! pla9 aft] ! l&w>d portion 0 above tide1 & ! coa/al pla9 may come to h a 8belt$0 or zon$ "*4 ,! /reams tribut>y to ^? l>g] ones :i* h tr5*$ ! pla9 may enc\nt] 9 turn h>d] & s(t] lay]s ( ! pla9 deposits1 & at ea* h>d lay] w be deflect$ along its m>g9 s z to ent] ! ma9 /reams m ne>ly at "r angles4 ,!y w also1 z "t goes on1 migrate lat]ally seaw>d ?r\gh und]m9+ ( ! h>d] lay]s1 & ?us w be %ap$ alt]nat+ belts ( l[l& sep>at$ by esc>pm5ts 9 ! h>d] rock f ! residual high] slopes4 ,belts ( upl& ( ?is "* ^u a coa/al pla9 are call$ cue/as 7,fig4 #bgc74 ,illu/ration3 ,,fig4 #bgc4--;,ideal =m ( cue/as & int]m$iate l[l&s c>v$ f a coa/al pla9 7aft] ,davis74 ,! sudd5 uplifts ( ! coa/s4--,elevations ( ! coa/ :i* yield ! coa/al pla9 mu/ be acc\nt$ among ! sl[] e>? movem5ts t result 9 *anges ( level4 ,su* movem5ts1 in/ead ( be+ accompani$ by disa/r\s e>?quakes1 7 probably m>k$ by frequ5t slight %ocks only1 by subt]ranean rumbl+s1 or1 x may be1 ! l& rose gradually )\t manife/ations ( a s5sible "*4 ,^u ^? coa/s :i* are (t5 9 ! ?roes ( seismic di/urbance1 a q diff]5t effect is to be obs]v$4 ,"h )9 ! rocks we w probably f9d ! m>ks ( rec5t fault+ ) l>ge displacem5ts1 & ! movem5ts h be5 ^u su* a scale t %ore features1 little modifi$ by subsequ5t wea!r+1 /& well above ! pres5t level ( ! seas4 ,above su* coa/s1 !n1 we recognize ! *>act]i/ic m>ks ( wave action1 & ! evid5ce t !y h be5 sudd5ly uplift$ is beyond "q4 ,illu/ration3 ,,fig4 #bgd4--,uplift$ sea cave1 t5 feet above ! wat] ^u ! coa/ ( ,cali=nia2 ! monum5t to a =m] e>?quake 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #bge4--;,d\ble-not*$ cliff ne> ,cape ,tiro1 ,celebes 7aft] a photograph by ,s>as974 ,! uprais$ cliff4--,^u ! coa/ ( s\!rn ,cali=nia may be f\nd all ! features ( wave-cut %ores n[ 9 p]fect pres]vation1 & 9 "s cases z mu* z fifte5 hundr$ feet above ! level ( ! sea4 ,^! features are monum5ts to ! gr&e/ ( e>?quake di/urbances :i* 9 rec5t "t h visit$ ! region 7,fig4 #bgd74 ,q z /rik+ an example ( simil> movem5ts is af=d$ by not*$ cliffs 9 h>d lime/one ^u ! %ore ( ! ,isl& ( ,celebes 7,fig4 #bge74 ,b ! coa/ ( ,cali=nia furni%es ! o!r *>act]i/ic coa/ features 9 ! high sea ar* & ! /ack z additional monum5ts to ! rec5t uplift4 ,let "o b imag9e ! /acks :i* n[ =m ! ,seal ,rocks (f ! ,cliff ,h\se at ,san ,francisco to be sudd5ly rais$ high above ! sea1 & ! =ms :i* !y w\ld !n pres5t w\ld diff] b little f ^? :i* are %[n 9 ,fig4 #bgf4 ,illu/ration3 ,,fig4 #bgf4--;,jasp] rock /acks uplift$ on ! coa/ ( ,cali=nia 7aft] a photograph by ,fairbanks74 ,! uplift$ b>ri] bea*4--,)9 ! rentrants ( ! %ore1 ! wave-cut cliff is1 z we "k1 replac$ by ! b>ri] bea*1 :i* takes its c\rse across ! entrance to a bay4 ,aft] an uplift1 su* a b>ri] compos$ ( s& or %+le %\ld be connect$ ) ! headl&s1 (t5 ) a p>tially fill$ lagoon beh9d x4 ,its cross section %\ld be /eep 9 ! direction ( ! lagoon1 b q gradual 9 front 7,fig4 #bgg74 ,illu/ration3 ,,fig4 #bgg4--,uplift$ %+le bea* across ! entrance to a =m] bay ^u ! coa/ ( s\!rn ,cali=nia 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #bgh4--,rais$ bea* t]races ne> ,elie1 ,fife1 ,scotl&4 ,coa/ t]races4--,^u ^? %ores :]e to-day high m\nta9s front ! sea1 ! coa/ may g5]ally be se5 to rise 9 a s]ies ( t]races 7,fig4 #bgh74 ,?is is notably true ( ^? coa/s :i* are to-day rack$ by e>?quakes1 su* z is ! ea/]n m>g9 ( ! ,pacific f ,alaska to ,patagonia4 ,! travel] by /eam] along ! coa/ f ,san ,francisco to ,*ili has = weeks almo/ con/antly 9 sight ^! giant /eps on :i* ! m\nta9s h be5 uplift$ f ! sea4 ,9 ,alaska we are =tunate 9 hav+ ! hi/ory ( ! lat] /ages 9 ?is uplift 7,fig4 #bgi74 ,z describ$ 9 a =m] *apt]1 portions ( ?is %ore rose 9 ! mon? ( ,septemb] ( ! ye> #ahii 9 "s places z high z =ty-sev5 feet1 to ! accompanim5t ( a t]rific e>?quake & sea wave4 ,above ! t]race :i* m>ks ! bea* l9e ( #ahii !re is a high] t]race ( simil> =m n[ ov]gr[n ) trees1 b none ! less cle>ly to be recogniz$ z a %ore l9e ( ! pa/ c5tury :i* prec$$ 9 ! long sequ5ce ! uplift ( #ahii4 ,illu/ration3 ,,fig4 #bgi4--,uplift$ sea cliffs & t]races on ! coa/ ( ,russell ,fjord1 ,alaska 7aft] ,t>r & ,m>t974 ,illu/ration3 ,,fig4 #bhj4--;,diagrams to %[ h[ excessive s9k+ ^u ! sea floor w cause ! %ore to migrate l&w>d z x is uplift$4 ,illu/ration3 ,,fig4 #bha4--;,a dr[n$ riv] m\?1 or e/u>y ^u a coa/al pla94 ,z 0 not$ 9 our /udy ( e>?quakes1 ! rec5t in/rum5tal records ( di/ant e>?quakes tell u t ! movem5ts ^u ! sea floor are _m times l>g] ?an ^? ^u ! cont95ts1 & t :ile ! m\nta9\s coa/s are g5]ally ris+1 ! deeps ( ! sea are s9k+4 ,! effect ( ?is ov]-balance ( s9k+1 or resultant %r9k+ ( ! e>?'s %ell1 may be to compress ! m\nta9 di/rict & s cause ! %ore l9e to move l&w>d at ! same "t t x moves upw>d 7,fig4 #bhj74 ,! sunk or embay$ coa/4--,:5 n[1 ^u ! o!r h&1 a section ( ! coa/ l9e s9ks ) ref]5ce to ! sea1 ! wat] invades all ! ne>-%ore valleys1 ?us 8dr[n+0 !m & yield+ ! dr[n$ riv] m\? or e/u>y4 ,if ! relief ( ! %ore 0 slight1 z x g5]ally is ^u a coa/al pla91 slight depression only w produce broad e/u>ies1 su* z ,*esapeake ,bay at ! dr[n$ m\? ( ! ,susquehanna 7,fig4 #bha74 ,if1 on ! o!r h&1 ! relief ( ! %ore is /rong & ! subsid5ce is l>ge1 ! entire coa/ l9e w be trans=m$ into an ar*ipelago ( /eep-wall$ rocky islets :i* rise abruptly f ! sea 7,figs4 #bhb & #bhd74 ,a plateau :i* is int]sect$ by deep & /eep-wall$ valleys ( ,u-section 7p4 #cda7 "u l>ge subm]g5ce yields ! fjords s *>act]i/ic ( ,sc&9avia or ,alaska4 ,a ragg$ coa/ l9e1 fr+$ ) isl&s z a result ( subm]g5ce1 is describ$ z an embay$ coa/4 ,illu/ration3 ,,fig4 #bhb4--;,ar*ipelago ( /eep rocky islets due to l>ge subm]g5ce ( a coa/ hav+ /rong relief4 ,entrance to ,esquimalt ,h>bor1 ,vanc\v] ,isl& 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #bhc4--,! subm]g$ ,hudsonian *annel :i* cont9ues ! ,hudson ,riv] across ! cont95tal %elf4 ,subm]g$ riv] *annels4--,! s9k+ ( a coa/ ( small relief be suffici5t to completely subm]ge riv] valleys1 ^: *annels !n beg9 to fill ) s$im5t & ^: c\rses c only be foll[$ 9 s\nd+s4 ,"o ( ! mo/ int]e/+ ( su* *annels is t :i* cont9ues ! ,hudson ,riv] across ! cont95tal %elf into ! deep] sea 7,fig4 #bhc74 ,records ( an oscillation ( movem5t4--,because a coa/ is deeply embay$ is no gr\nd = assum+ t a subsid5ce is n[ 9 progress1 or is1 9 fact1 ! late/ movem5t record$ ^u ! coa/4 ,9 _m cases x is easy to see t su* is n ! case4 ,! coa/ ( ,ma9e is p]haps z typical ( an embay$ %ore l9e z any t might be cit$1 b a /udy ( ! riv] valleys 9 ! neighborhood %[s cle>ly t ! pres5t subm]g5ce ( _! m\?s is a fraction only ( an e>li] "o :i* has left a record ( its exi/5ce 9 b$s ( m>9e clay :i* outl9e ! e>li] & f> deep] ind5tations 7,fig4 #bhd74 ,illu/ration3 ,,fig4 #bhd4--,m>9e clay deposits ne> ! m\?s ( ! riv]s ( ,ma9e :i* pres]ve a record ( e>li] subsid5ce 7aft] ,/one74 ,if n[ we give a clos] exam9ation to ! coa/1 x is f\nd t !re are m>ks ( rec5t uplift 9 an ab&on$ %ore l9e n[ f> above ! rea* ( ! waves4 ,!re is "h1 !n1 ! record1 fir/ ( subsid5ce & consequ5t embaym5t1 &1 lat]1 ( an uplift :i* has r$uc$ ! ragg$ness ( ! coa/ outl9e expos$ ! clay deposits1 & rais$ ! /r&s ( ! p]iod ( deep subsid5ce to _! pres5t position4 ,9 c\ntries :i* possess a m anci5t civilization ?an our own1 ! record ( su* oscillations 9 ! level ( ! gr\nd has sometimes be5 ent]$ ^u human monum5ts1 s t x is possible to date m or less def9itely ! p]iods ( subsid5ce or elevation4 ,at ! little t[n ( ,pozzuoli1 ^u ! %ore ( ! ,bay ( ,naples1 is f\nd "o ( ! mos in/ructive ( ^! records4 ,illu/ration3 ,,fig4 #bhe4--,view ( ! ?ree /&+ columns ( ! temple ( ,jupit] ,s]apis at ,pozzuoli1 %[+ ! d>k & r\gh b& n9e feet 9 wid? affect$ by ! rock-bor+ mollusks :i* n[ live 9 ! ,bay ( ,naples4 ,9 ! ru9s ( ! anci5t temple ( ,jupit] ,s]apis are ?ree m>ble monoli?s #dj feet 9 height1 curi\sly m>k$ by a r\gh5$ surface betwe5 ! heights ( #ab & #ba feet above _! p$e/als 7,fig4 #bhe74 ,clos] inspection %[s t ?is r\gh5$ surface has be5 produc$ by a m>9e1 rock-bor+ mollusk1 ! li?odomus1 :i* lives 9 ! wat]s ( ! ,bay ( ,naples1 & ! %ells ( ?is animal are /ill to be f\nd )9 ! cavities ^u ! surface ( ! columns4 ,)\t rec\nt+ details :i* h be5 _m times recit$ s9ce ^! int]e/+ monum5ts 7 fir/ geologically explor$ by ,babbage & ,lyell1 x may be /at$ t a record is "h pres]v$1 fir/ ( subsid5ce am\nt+ to "s #dj feet1 & ( subsequ5t elevation1 ( ! l[ coa/ l& on :i* /ood ! temple 9 ! old ,roman city ( ,puteoli 7,fig4 #bhf74 ,at ! "t ( deepe/ subm]g5ce ! top ( ! li?odomus zone ^u ! column /ood at ! level ( ! wat] 9 ! ,bay ( ,naples1 ! smoo!r l[] zone be+ buri$ at ! "t 9 ! s& at ! bottom1 & ?us made inaccessible = ! li?odomi4 ,x is to be add$ t /udies made 9 ! environs ( ,pozzuoli h fully confirm$ ! *anges ( level reveal$ by ! columns1 ?r\gh ! discov]y ( n[ elevat$ %ore l9es :i* are ref]able to ! p]iod ( deep subm]g5ce4 ,simultane\s contr>y movem5ts ^u a coa/4--,9 our /udy ( ! *anges 9 ! level ( ! gr\nd t take place dur+ e>?quakes1 x 0 le>n$ t neighbor+ sections ( ! e>?'s cru/ may be mov$ at diff]5t rates or ev5 9 opposite directions1 not)/&+ ! fact t ! g5]al movem5t ( ! prov9ce is "o ( uplift4 ,?us dur+ ! ,alaskan e>?quake ( #ahii1 al?\gh portions ( ! coa/ l9e 7 elevat$ by z mu* z =ty-sev5 feet1 neighbor+ sections 7 rais$ by small] am\nts1 & "s small sections 7 sunk & s f> subm]g$ t ! salt wat] & ! bea* s& 7 wa%$ ab\t ! roots ( =e/ trees4 ,illu/ration3 ,,fig4 #bhf4--,pozzuoli 9 ! #crd1 #i?1 & #bj? ,c5turies4 ,a region rack$ by heavy e>?quakes1 :]e ! pres5t configuration ( ! gr\nd speaks /rongly = a movem5t ( some:at simil> nature1 b ) av]age movem5t ( elevation mu* great] to ! nor?w>d ?an 9 ! opposite direction1 is ! ext5d$ coa/ l9e ( ,*ili4 ,?is c\ntry is *>act]iz$ by a great c5tral nor? & s\? valley :i* sep>ates ! coa/ range f ! high *a9 ( ! ,cordill]as to ! ea/w>d4 ,to ! s\?w>d ! floor ( ?is valley desc5ds1 & has its cont9uance 9 ! ,gulf ( ,corcovado beh9d ! isl& ( ,*iloe & ! ,*onos ar*ipelago4 ,! kn[n rec5t uplift ( ! coa/ ( ,*ili1 p>ticul>ly 9 ! nor!rn sections & dur+ ! e>?quakes ( ! eighte5?1 n9ete5?1 & tw5tie? c5turies1 l5ds great int]e/ to ?is topographic peculi>ity4 ,indications are n lack+ t1 dur+ ! e>?quake ( ,concepcion 9 #ahce1 & ( ,valp>aiso 9 #aijg1 ! measure ( uplift 0 great] to ! nor? ?an x 0 to ! s\?4 ,illu/ration3 ,,fig4 #bhg4--,map ( ,san ,clem5te ,isl&1 ,cali=nia1 %[+ ! *>act]i/ic topography ( rec5t uplift 7aft] ,u4 ,s4 ,coa/ & ,geodetic ,survey74 ,! contra/$ isl&s ( ,san ,clem5te & ,santa ,catal9a4--,p]haps ! mo/ /rik+ example ( simultane\s opposite movem5ts obs]vable 9 neighbor+ portions ( ! e>?'s cru/ is furni%$ by ! coa/ ( s\!rn ,cali=nia4 ,! coa/ itself at ,san ,p$ro & ! isl& ( ,san ,clem5te1 "s fifty miles (f ?is po9t1 9 common ) mo/ portions ( ! neighbor+ coa/ l&1 h be5 ris+ 9 int]rupt$ movem5ts f ! sea1 & (f] 9 r>e p]fection ! *>act]i/ic coa/ t]races 7,fig4 #bhg & ,fig4 #bgh1 p4 #bej74 ,midway betwe5 ^! two ris+ sections ( ! cru/1 & less ?an tw5ty-five miles di/ant f ei!r1 is ! isl& ( ,santa ,catal9a1 :i* has be5 s9k+ b5ea? ! waves1 & app>5tly at a simil>ly rapid rate 7,fig4 #bhh74 ,! topography ( ! isl& %[s ! intricate detail ( a maturely erod$ surface1 :ile t ( ! neighbor+ ,san ,clem5te %[s only ! widely spac$1 deep caons ( ! infantile /age ( erosion 7,fig4 #afe & pl4 #ab ,a74 ,:ile ,santa ,catal9a has be5 s9k+1 ,san ,p$ro ,hill has ris5 #abdj feet1 & ,san ,clem5te1 #aejj feet4 ,x is *>act]i/ic ( a s9k+ coa/ l9e t ! cliff recession is abnormally rapid1 & evid5ce = ?is is furni%$ by ! %ores ( ,santa ,catal9a1 ^u :i* ! waves are cutt+ ! cliffs back into ! b$s ( caons1 & s caus+ small falls to develop at ! caon m\?s4 ,,plate #ab4 ,illu/ration3 ,a4 ,v-%ap$ caon cut 9 an upl& rec5tly elevat$ f ! sea1 ,san ,clem5te ,isl&1 ,cali=nia 7aft] ,w4 ,s4 ,tangi]-,smi?74 ,illu/ration3 ,b4 ,a 8hogback0 at ! base ( ! ,bighorn ,m\nta9s1 ,wyom+ 7aft] ,d>ton74 ,illu/ration3 ,,fig4 #bhh4--,map ( ,santa ,catal9a ,isl&1 ,cali=nia1 %[+ ! *>act]i/ic surface ( an area :i* has long be5 above ! waves1 & ! entire abs5ce ( coa/ t]races 7aft] ,u4 ,s4 ,c4 & ,g4 ,s474 ,! ,blue ,grotto ( ,capri4--,we may n[ return to ! ,bay ( ,naples = additional evid5ce t oscillations ( level 9 neighbor+ portions ( ! same coa/ are n necess>ily syn*ron\s1 & t ne>-ly+ sections may ev5 move 9 opposite directions at ! same "t1 z has already be5 %[n = ! isl&s (f ! ,cali=nia coa/4 ,= ! ,pozzuoli %ore ( ! bay x 0 le>n$ t )9 ! ,*ri/ian ,era a complete cycle ( d[nw>d1 foll[$ by lat] upw>d1 movem5t has be5 l>gely accompli%$4 ,across ! bay1 & less ?an #bj miles di/ant1 is ! ,blue ,grotto ( ,capri1 a sea cave cut 9 lime/one above an e>li] cave ( ! same nature :i* is n[ deep bel[ ! wat] surface4 ,x is ! refract$ sunlight :i* ent]s ! cave ?r\gh ?is l[] subm]g$ op5+ & has be5 robb$ on ! way ( all b its blue rays :i* gives to ! fam\s grotto its special *>m 7,fig4 #bhi74 ,illu/ration3 ,,fig4 #bhi4--;,cross section ( ! ,blue ,grotto on ! ,isl& ( ,capri1 %[+ ! subm]g$ sea cave ?r\gh :i* mo/ ( ! light ent]s ! grotto1 & ! high] artificial w9d[ n[ wid5$ by wave action 7aft] von ,knebel74 ,x is kn[n t ! =m]1 & n[ subm]g$1 sea cave 0 9 use by ,roman patricians z a cool retreat f ! oppressive hot w9d kn[n z ! sirocco1 & t an artificial entrance or w9d[ 0 cut :]e is n[ ! only accessible entrance to ! grotto4 ,9 ! anci5t writ+s1 no m5tion is made1 h[ev]1 ( ! rem>kable blue illum9ation = :i* x is n[ fam\s1 & ! conditions at ! "t1 z we may see1 7 n su* z to make ?is possible4 ,lat] subsid5ce ( ! coa/ has br\ght ! anci5t w9d[ to ! sea level1 :]e x has be5 consid]ably enl>g$ by ! waves4 ,! e>li] grotto1 ab&on$ z its entrance 0 clos$1 0 r$iscov]$ 9 #ahbf by ! pa9t] & poet1 ,augu/ ,kopis*4 ,a grotto ) gre5 illum9ation 7! ,grotto ,v]de7 is situat$ ^u ! opposite side ( ! isl&1 & a blue grotto1 hav+ its orig9 9 simil> conditions to ^? ( ! fam\s ,blue ,grotto1 is f\nd ^u ! isl& ( ,busi (f ! ,dalmatian coa/4 ,"* pr(iles4--,9 ! l&scape ( a coa/ :i* has be5 sl[ly uplift$ ! *>act]i/ic l9e is ! pr(ile ( ! cue/a1 ) %ort p]p5dicul> elem5t jo9$ to a g5tly slop+ & long] section & cont9u$ 9 ! horizontal portion correspond+ to ! l[l& 7,fig4 #bij74 ,rapidly uplift$ coa/s (f] 9 contra/ ! l9es *>act]i/ic ( wave erosion & deposition1 b at high] levels & 9 repeat$ sections4 ,mo/ prom95t ( all is ! /aircase con/ruct$ ( coa/ t]races1 ) ei!r v]tical or slop+ ris]s & ) outw>dly incl9+ & g5tly grad$ treads4 ,ne> ! /eep ris] 9 ! /aircase may sometimes be se5 ! sug>-loaf outl9e ( ! /ack cut 9 s(t] mat]ial1 or ! obelisk-l pill> und]cut at its base1 :i* is c>v$ 9 firm] rock masses4 ,) excessively rapid uplift1 ! d\ble-not*$ cliff or ! d\ble sea ar* may appe> 9 ! l&scape4 ,^u a subm]g$ coa/ ! mo/ significant l9es 9 ! view are ^? ( ! rock islet & ! /eep-wall$ fjord4 ,illu/ration3 ,,fig4 #bij4--;,"* pr(iles 9 coa/ l&scapes :]e !re has be5 ei!r elevation or depression4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xix ,g5]al3-- ,,sir ,,*4 ,,lyell4 ,pr9ciples ( ,geology1 vol4 #b1 pp4 #ahj-aig4 ,,ed4 ,,suess4 ,! ,face ( ! ,e>?1 ,cl>5don ,press1 ,ox=d1 #aijf1 vol4 #b1 ,*apt]s i & xiv1 pp4 #a-bi1 #ece-eef4 ,,rob]t ,,sieg]4 ,se5s*wankung5 und ,/r&v]s*iebung5 9 ,sc&9avi51 ,zeit4 d4 ,gesell4 f4 ,erdk41 ,b]l91 vol4 #bh1 #ahic1 pp4 #a-ajf1 #cic-fhh1 pl4 #g4 ,elevat$ %ore l9es3-- ,f4 ,b4 ,,taylor4 ,! ,highe/ ,old ,%ore ,l9e ( ,mack9ac ,isl&1 ,am4 ,j\r4 ,sci41 vol4 #dc1 #ahib1 pp4 #baj-bah4 ,,?omas ,l4 ,,watson4 ,evid5ces ( ,rec5t ,elevation ( ! ,s\!rn ,coa/ ( ,baff9s ,l&1 ,j\r4 ,geol41 vol4 #e1 #ahig1 pp4 #ag-cc4 ,j4 ,w4 ,,gold?wait4 ,! ,ab&on$ ,%ore ,l9es ( ,ea/]n ,wiscons94 ,bull4 #ag1 ,wis4 ,geol4 & ,nat4 ,hi/4 ,surv41 #aijg1 pp4 #acd1 pls4 #a-cg4 ,evid5ces ( depression3-- ,w4 ,b4 ,,scott4 ,introduction to ,geology1 ,new ,york1 #aijg1 pp4 #cc-cf4 ,w4 ,j4 ,,mcgee4 ,! ,gulf ( ,mexico z a ,measure ( ,iso/acy1 ,am4 ,j\r4 ,sci4 7#c71 vol4 #dd1 #ahib1 pp4 #agg-aib4 ,a4 ,,l9d5kohl4 ,notes on ! ,subm>9e ,*annel ( ! ,hudson ,riv]1 etc41 ,am4 ,j\r4 ,sci4 7#c71 vol4 #da1 #ahia1 pp4 #dhi-dii1 pl4 #ah4 ,j4 ,w4 ,,sp5c]4 ,! ,subm>9e ,great ,caon ( ! ,hudson ,riv]1 ibid4 7#d71 vol4 #ai1 #aije1 pp4 #a-ae2 ,subm>9e ,valleys (f ! ,am]ican ,coa/ & 9 ! ,nor? ,atlantic1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ad1 #aijc1 pp4 #bjg-bbf1 pls4 #ai-bj4 ,f4 ,,nans54 ,! ,ba?ymetrical ,features ( ! ,nor? ,pol> ,sea1 ) a ,discussion ( ! ,cont95tal ,%elves & ,previ\s ,oscillations ( ,%ore ,l9e1 ,norwegian ,nor? ,pol> ,exp$ition1 vol4 #d1 #aijd1 pp4 #ii-bca1 pl4 #a4 ,w4 ,v4 ,,knebel4 ,hhl5kunde1 etc41 ,brauns*weig1 #aijf1 pp4 #age-agg 7! blue grotto ( ,capri74 ,oscillation ( movem5t3-- ,c4 ,,lyell4 ,pr9ciples ( ,geology1 vol4 #b1 pp4 #afd-agf 7,temple ( ,jupit] ,s]apis74 ,e4 ,,ray ,,lanke/]4 ,ext9ct ,animals1 ,new ,york1 #aije1 pp4 #ca-db4 ,h4 ,w4 ,,fairbanks4 ,oscillations ( ! ,coa/ ( ,cali=nia dur+ ! ,plioc5e & ,plei/oc5e1 ,am4 ,geol41 vol4 #bj1 #ahig1 pp4 #bac-bde4 ,g4 ,h4 ,,/one4 ,mon4 #cd1 ,u4 ,s4 ,geol4 ,surv41 #ahii1 pp4 #ef-eh1 pl4 #b4 ,,bailey ,,willis4 ,ames ,knob1 ,nor? ,hav51 ,ma9e4 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ad1 #aijc1 pp4 #bja-bjf1 pls4 #ag-ah4 ,simultane\s contr>y movem5ts on a coa/3-- ,a4 ,c4 ,,lawson4 ,! ,po/-,plioc5e ,dia/rophism ( ! ,coa/ ( ,s\!rn ,cali=nia1 ,bull4 ,univ4 ,calif4 ,dept4 ,geol41 vol4 #a1 #ahic1 pp4 #aae-afj1 pls4 #h-i4 ,w4 ,s4 ,,tangi]-,,smi?4 ,a ,geological ,sket* ( ,san ,clem5te ,isl&1 #ah? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 ii1 #ahih1 pp4 #dei-dif1 pls4 #hd-if4 ,r4 ,s4 ,,t>r & ,l4 ,,m>t94 ,rec5t ,*anges ( ,level 9 ! ,yakutat ,bay ,region1 ,alaska1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ag1 #aijf1 pp4 #bi-fd1 pls4 #ab-bc4 ,,*apt] ,,xx ,,! ,,glaci]s ,,( ,,m\nta9 ,,& ,,cont95t ,conditions ess5tial to glaciation4--,:]ev] = a suffici5tly protract$ p]iod ! annual sn[fall ( a di/rict is 9 excess ( ! sn[ t is melt$1 a residue mu/ rema9 f ea* season to be add$ to t ( succe$+ ones4 ,ev5tually s mu* sn[ w h accumulat$ t "u its own weight & 9 ob$i5ce to its peculi> prop]ties1 a movem5t w beg9 )9 ! mass t5d+ to spread x & s to r$uce ! slope ( its upp] surface 7,frontispiece plate74 ,! conditions favorable to glaciation are1 !re=e1 heavy precipitation & l[ annual temp]ature4 ,if ! precipitation is scanty1 ! small sn[fall is soon melt$2 & if ! temp]ature be too high1 ! moi/ure is precipitat$ n 9 ! =m ( sn[ b z ra94 ,x is important "h to keep 9 m9d t sn[ is a poor heat conductor & itself protects its deep] lay]s f melt+4 ,! sn[-l9e4--,because ( ! l[ temp]atures glaci]s %\ld be mo/ abundant or mo/ ext5sive 9 high latitudes & 9 high altitudes4 ,! l>ge/ are f\nd 9 pol> & subpol> regions1 & !y are else:]e enc\nt]$ only at consid]able elevations4 ,! l>ge/ glaci]s are ! va/ %eets ( ice :i* inwrap ! cont95ts ( ,gre5l& & ,ant>ctica1 b glaci]s ( l>ge size are to be f\nd ^u o!r l>ge l& masses ( ! ,arctic1 z well z 9 ,alaska1 9 ! s\!rn ,&es1 & 9 ,new ,zeal&4 ,mu* small] glaci]s are *>act]i/ic ( c]ta9 highl&s )9 temp]ate & tropical regions1 b because ( specially favorable conditions bo? ( altitude & precipitation ! ,himalayas1 al?\gh 9 relatively l[ latitudes1 n\ri% glaci]s ( l>ge proportions4 ,9 g5]al1 x may be said t ! n\ri%+ gr\nds ( glaci]s are l>gely re/rict$ to ^? areas :]e sn[ cov]s ! gr\nd ?r\gh\t ! ye>4 ,! l[] m>g9 ( su* areas is designat$ ! sn[ l9e1 & v>ies b little f ! l9e on :i* ! av]age summ] temp]ature is at ! freez+ po9t ( wat]--! s-call$ summ] iso!rm ( #cb ,fahr5heit4 ,)9 ! tropics ?is l9e may rise z high z #ah1jjj feet above ! sea1 :]eas 9 pol> latitudes x desc5ds to sea level4 ,importance ( m\nta9 b>ri]s 9 initiat+ glaci]s4--,! precipitation )9 any di/rict dep5ds1 h[ev]1 n alone ^u ! am\nt ( moi/ure :i* is br\ght to x 9 ! cl\ds1 b ^u ! am\nt :i* is ab/ract$ be=e ! cl\ds h pass$ ov] x4 ,! capacity ( space to hold moi/ure increases ) its temp]ature1 & h5ce any l[]+ ( ?is temp]ature w r$uce ! capacity4 ,if l[]$ suffici5tly1 ! po9t ( complete saturation w be rea*$ & fur!r cool+ mu/ result 9 precipitation4 ,h5ce1 any?+ :i* =ces an air curr5t to rise into m r>efi$ zones above1 w l[] ! pressure ^u x & s br+ ab\t a cool+ effect 9 :i* no heat is ab/ract$4 ,?is s-call$ adiabatic refrig]ation ( a gas may be illu/rat$ by ! cool curr5t :i* issues 9 a jet f a w>m exp&$ rubb] tire aft] ! cock has be5 op5$2 or ev5 bett]1 by ! in/ant solidification at extreme l[ temp]atures ( su* normal gases z c>bonic acid :5 !y are all[$ to issue "u heavy pressure f a small orifice4 ,z appli$ to moi/ure-lad5 & ne>-surface w9ds1 ! effective ag5ts ( adiabatic cool+ are ! upl& areas ^u ! cont95ts1 & especially ! ranges ( m\nta9s4 ,^! b>ri]s =ce ! mov+ cl\ds to rise1 cool1 & deposit _! moi/ure4 ,x is1 !re=e1 ! highl& b>ri]s :i* face ! oncom+1 moi/ure-lad5 w9ds t receive ! heavie/ precipitation4 ,)9 temp]ate regions1 because ( ! preval5ce ( we/]ly w9ds1 ^? b>ri]s :i* face ! we/]n %ores receive ! heavie/ fall4 ,)9 ! tropics1 on ! o!r h&1 x is ! b>ri]s fac+ ! ea/]n %ores :i*1 because ( ! ea/]ly 8trades01 are mo/ favorable to precipitation4 ,?us x is 9 ! ,si]ra ,nevadas ( ,cali=nia1 & n 9 ! ,rockies or ! ,appala*ians1 t ! glaci]s ( ! ,unit$ ,/ates are f\nd4 ,! highl& ( ! ,swiss ,alps ly+ likewise a?w>t ! 8we/]lies0 ( ! temp]ate zone acquires ! moi/ure = n\ri%m5t ( its glaci]s f ! we/]n ocean--"h ! ,atlantic 7,fig4 #bia74 ,)9 ! tropics ! conditions are rev]s$1 & x is 9 g5]al ! ranges :i* lie ne>] ! ea/]n coa/s t are ! m favor$4 ,if no b>ri] is f\nd ^u ?is coa/1 ! cl\ds may travel ov] va/ /ret*es ( c\ntry be=e be+ arre/$ by m\nta9s & robb$ ( _! moi/ure4 ,?us 9 tropical ,brazil ! glaci]s are f\nd 9 ! ,&es ^u ! ,pacific coa/ ?\gh n\ri%$ by cl\ds f ! ,atlantic4 ,illu/ration3 ,,fig4 #bia4--,map %[+ ! di/ribution ( exi/+ glaci]s1 & ! two important w9d poles ( ! e>?4 ,s5sitiv5ess ( glaci]s to temp]ature *anges4--,h[ s5sitive is ! adju/m5t betwe5 sn[ precipitation & temp]ature may be /rik+ly illu/rat$ by ! /atem5t on excell5t au?ority t if ! av]age annual temp]ature ( ! air )9 ! ,scotti% ,highl&s %\ld be l[]$ by only ?ree degrees ,fahr5heit1 small glaci]s w\ld be ! result2 & a mod]ate temp]ature fall )9 ! region surr\nd+ ! ,laur5tian lakes ( ,nor? ,am]ica w\ld br+ on glaciation1 o!rwise express$ z a depression ( ! sn[ l9e ( ! region4 ,! cycle ( glaciation4--,?\gh to-day buri$ b5ea? its ice mantle1 x is kn[n t ,gre5l& _h m ?an once 9 e>li] geological ages a notably mild climate1 & 9 "s future age x may rev]t to ?is condition4 ,9 o!r regions1 also1 we h evid5ce t su* a rotation ( climatic *anges has be5 successively accompli%$1 ! climate hav+ /eadily increas$ 9 sev]ity t[>ds a culm9at+ po9t1 & be5 foll[$ by a rev]se s]ies ( *anges4 ,su* a complete p]iod may be call$ a cycle ( glaciation4 ,:ile ! climate is /eadily becom+ m rigor\s1 we h to d ) an advanc+ hemicycle ( glaciation1 b aft] ! culm9at+ po9t has be5 rea*$1 ! p]iod ( amelioration ( climate is ! rec$+ hemicycle4 ,! advanc+ hemicycle4--,!re is little reason to d\bt t :atev] be ! cause ( ! climatic *anges :i* br+ on glacial conditions1 ^! *anges come on by ins5sible gradations4 ,! fir/ visible evid5ce ( ! increas$ sev]ity ( ! climate is ! long] p]si/5ce ( ! w9t] sn[s1 at fir/ )9 ! m elevat$ di/ricts4 ,9 su* positions drifts mu/ ev5tually cont9ue ?r\gh\t ! w>m season & s contribute to ! sn[ accumulations ( ! succe$+ w9t]4 ,?is po9t once rea*$1 small glaci]s are inevitable1 ev5 %\ld ! av]age temp]ature fall no fur!r1 = ! sn[ left ov] 9 ea* season mu/ /eadily increase ! dep? ( ! deposits until ! weight br+s ab\t an int]nal motion ( ! mass f high] to l[] levels4 ,illu/ration3 ,,fig4 #bib4--;,an ,alaskan glaci] spread+ out at ! foot ( ! range :i* n\ri%es x4 ,! inh]it$ depressions ( ! upl&--! g5tle holl[s at ! heads ( riv]s--w fir/ be fill$1 & s ! valleys bel[ become ! natural *annels = ! outfl[ ( ! e>ly glaci]s4 ,) a cont9u$ l[]+ ( ! annual temp]ature & consequ5t increas$ sn[fall1 ! e>ly glaci]s become m & m amply n\ri%$4 ,sn[ & ice w1 !re=e1 cov] l>g] areas ( ! upl&1 & ! glaci]s w pu% _! fronts f>!r d[n ! valleys be=e !y are wa/$ 9 ! w>m air ( ! l[] levels4 ,z ! valleys become ?us m completely inve/$ by ! glaci] !y are likewise fill$ to great] & great] dep?s1 & !y may ?us subm]ge portions ( ! walls t sep>ate adjac5t valleys4 ,rea*+ at la/ ! front ( ! upl& area1 ! glaci]s may n[ be s well n\ri%$ at _! heads t !y pu% out ^u ! flatt] =el& & )\t re/ra9t f reta9+ walls spread broadly ^u x 7,fig4 #bib74 ,illu/ration3 ,,fig4 #bic4--,surface ( a glaci] ^: upp] lay]s spread ) slight re/ra9t f reta9+ walls4 ,surface ( ! ,folgefond1 an ice cap ( s\!rn ,norway4 ,! culm9ation ( ! progressive climatic *ange may ere ?is h be5 rea*$ & mild] conditions h ensu$4 ,if1 h[ev]1 ! sev]ity ( ! climate %\ld be /ill fur!r increas$1 ! exp&$ fronts ( neighbor+ glaci]s w coalesce to =m a common ice fan or apron along ! foot ( ! upl& 7,plate #ah ,b74 ,?is c\ld h>dly take place )\t a /ill fur!r deep5+ ( ! ice )9 ! valleys above1 &1 probably1 a progressive subm]g5ce ( ! l[] cre/s 9 ! valley walls4 ,?is may ev5 cont9ue until all p>ts ( ! upl& area h be5 buri$4 ,! sn[ & ice n[ take ! =m ( a cov]+ cap or c>apace1 & ! upp] portions be+ no long] re/ra9$ at ! sides1 n[ spread into a broad dome1 z w\ld a visc\s liquid l ?ick molasses :5 p\r$ out ^u ! floor 7,fig4 #bic74 ,! l[] zones ( ! mass & ! ?9n] m>g9al portions /ill h _! motion to a great] or less ext5t controll$ by ! irregul>ity ( ! rock floor aga9/ :i* !y re/4 ,! rev]se s]ies ( *anges 9 ! glaci] is inaugurat$ by an amelioration ( ! climate1 & "h1 !re=e1 ! advanc+ hemicycle becomes m]g$ 9 ! rec$+ hemicycle ( glaciation4 ,cont95tal & m\nta9 glaci]s contra/$4--,! "t :5 ! rock surface becomes subm]g$ b5ea? ! glaci] is1 z reg>ds bo? ! surface =ms & ! erosive "w1 a critical po9t ( mu* significance2 = ! ice cap & l>g] cont95tal glaci] obvi\sly protect ! rock surface f ! action ( ^? *emical & me*anical processes 9 :i* ! atmosph]e ent]s z *ief ag5t1 & :i* are collectively kn[n z wea!r+ processes4 ,until subm]g5ce is accompli%$1 l>g] or small] portions ( ! rock surface project ei!r ?r\gh or betwe5 ! ice masses & are1 !re=e1 expos$ to direct attack by ! wea!r 7see bel[1 p4 #cgj74 ,illu/ration3 ,,fig4 #bid4--,section ?r\gh a m\nta9 glaci] 79 solid black71 %[+ h[ its surface is det]m9$ by ! irregul>ities 9 ! rock basem5t 7aft] ,hess74 ,sn[ :i* falls 9 ! m\nta9s is n all[$ to rema9 long :]e x falls4 ,by ! fir/ high w9d x is swept (f ! m elevat$ & expos$ surfaces & collect$ "u eddies 9 any exi/+ holl[s1 b especially ^? ^u ! lee slopes ( ! range4 ,we are to le>n t glaci]s c>ve ! m\nta9s by enl>g+ ! holl[s :i* !y f9d & produc+ great bas9s = ! collection ( _! sn[s2 b ) ! initiation ( glaciation ! inh]it$ holl[s are 9 mo/ cases ! unimportant depressions at ! heads ( /reams4 ,:atev] !y may be & h[ev] =m$1 ! sn[ fir/ fills ^? holl[s :i* are %elt]$ f ! w9d1 & z x accumulates & becomes di/ribut$ z ice1 assumes a surface ( its own t is dep5d5t ^u ! =m & ! position ( ! bas9 :i* x occupies 7see ,fig4 #bid74 ,illu/ration3 ,,fig4 #bie4--,pr(ile across ! l>ge/ ( ! ,icel&ic ice caps1 ) ! v]tical scale greatly exagg]at$ 7aft] ,?orodds5 & ,spe?mann74 ,:5 ! quantity ( accumulat$ sn[ is s great t all holl[s ( ! rock surface are fill$1 its own surface is no long] controll$ by reta9+ rock walls1 & x n[ assumes a =m l>gely indep5d5t ( ! irregul>ities 9 ! upl&4 ,exp]i5ce %[s t ?is surface is approximately t ( a flat dome or %ield1 & z x cov]s all ! upl&1 save :]e ! ice ?9s ^u its m>g9s1 ?is type ( glaci] is call$ an ice cap 7,fig4 #bie74 ,all types ( glaci] 9 :i* rock projects above ! highe/ levels ( ! ice & sn[ are kn[n z m\nta9 glaci]s4 ,illu/ration3 ,,fig4 #bif4--;,ideal section across a cont95tal glaci]1 ) ! v]tical scale & ! project+ rock masses ( ! m>g9al zone greatly magnifi$4 ,! flat domes ( ice :i* mantle ! cont95ts ( ,gre5l& & ,ant>ctica1 ?\gh resembl+ 9 =m ! small] ice cap1 are yet because ( _! va/ size s di/9ct f !m1 p>ticul>ly 9 ! mann] ( _! n\ri%m5t1 t !y belong 9 a sep>ate class describ$ z inl& ice or cont95tal glaci]s4 ,?\gh !y h "s aff9ities ) ice caps1 !y are mo/ %>ply diff]5tiat$ f all types ( m\nta9 glaci]s4 ,( !m x is true t ! li?osph]e projects ?r\gh !m only 9 ! neighborhood ( _! m>g9s 7,fig4 #bif71 :]eas 9 ! case ( m\nta9 glaci]s rock may project at any level b always above ! highe/ sn[ surface4 ,ice caps may be reg>d$ z int]m$iate betwe5 ! two ma9 classes ( m\nta9 & cont95tal glaci]s 7,fig4 #big74 ,because ( ! l>ge rle :i* cont95tal glaci]s h play$ 9 geological hi/ory1 x is ?\ght be/ to consid] !m fir/1 leav+ = lat] discussion ! no less int]e/+ b less important m\nta9 glaci]s4 ,illu/ration3 ,,fig4 #big4--,view ( ! ,eyriks-,jkull1 an ice-cap ( ,icel& 7aft] ,grossman74 ,! n\ri%m5t ( glaci]s4--,! life ( a glaci] is dep5d5t ^u ! cont9u$ deposition ( sn[ 9 aggregate am\nt 9 excess ( t :i* is lo/ by melt+ or by o!r deplet+ processes4 ,:5ev]1 on ! o!r h&1 ! wa/e exce$s ! precipitation1 ! glaci] is 9 a rec$+ condition & mu/ ev5tually disappe>1 if su* conditions are suffici5tly long cont9u$4 ,! s\rce ( ! sn[ is ! wat] ( ! ocean evaporat$ into ! atmosph]e & transport$ ov] ! l& 9 ! =m ( cl\ds4 ,we are to le>n t ! *anges :i* ?is moi/ure und]goes be=e its deliv]y to ! glaci] are notably diff]5t = ! classes ( cont95tal & m\nta9 glaci]4 ,! upp] & l[] cl\d zones ( ! atmosph]e4--,be=e we c compreh5d ! nature ( ! processes by :i* glaci]s are n\ri%$1 x w be necess>y to review ! results ( rec5t /udies made ^u ! e>?'s atmosph]ic envelope4 ,x mu/ be kept 9 m9d t ! sun's rays are *iefly effective 9 w>m+ ! atmosph]e ?r\gh be+ fir/ absorb$ by "s solid body su* z rock or wat] & _! heat !n communicat$ by contact to ! imm$iately adjac5t air lay]s4 ,! lay]s ?us w>m$ be+ n[ light] ?an be=e1 !y rise & are replac$ by cold] air1 :i* 9 its turn is w>m$ & likewise set 9 upw>d motion4 ,su* curr5ts develop$ 9 ! air by contact ) w>m] solid bodies con/itute ! process kn[n z convection4 ,illu/ration3 ,,fig4 #bih4--,! zones ( ! l[] atmosph]e z reveal$ by rec5t kite & balloon explorations4 ,to a relatively small degree ! atmosph]e is heat$ by ! direct absorption ( ! sun's rays :i* pass ?r\gh x4 ,s9ce air has weight1 x compresses ! l[] lay]s ne> ! e>?1 & h5ce z we asc5d f ! e>?'s surface ! air becomes cont9ually light]4 ,convection curr5ts mu/1 !re=e1 adju/ !mselves by ! air exp&+ z x rises4 ,b expansion ( a gas always results 9 its cool+1 z e "o mu/ h obs]v$ :o has plac$ 8 f+] 9 ! air curr5t :i* escapes f ! op5 valve ( a w>m rubb] tire4 ,dry air is cool$ a degree ,fahr5heit = e six hundr$ feet ( asc5t 9 ! atmosph]e4 ,at a height ( ab\t sev5 miles above ! e>?'s surface all ris+ air curr5ts h cool$ to ab\t #fh bel[ ! z]o ( ! ,fahr5heit scale1 & exploration ) balloons has %[n t ! curr5ts rise no f>!r4 ,at ?is level !y move horizontally1 j z ris+ vapor spreads out 9 a room b5ea? ! ceil+4 ,above ?is level1 z f> z exploration has gone1 or to a height ( m ?an twelve miles1 ! temp]ature rema9s ne>ly con/ant1 & ?is upp] zone is1 !re=e1 call$ ! iso!rmal or ! advective zone--! uni=m temp]ature zone ( ! l[] atmosph]e4 ,b5ea? ! convective ceil+ ! process ( convection is *>act]i/ic1 & ?is zone is !re=e describ$ z ! convective zone 7,fig4 #bih74 ,a l>ge "p ( ! moi/ure :i* rises f ! ocean's surface is cond5s$ to vapor be=e x has asc5d$ ?ree miles1 & 9 ?is =m x makes its transit ov] l& z fleecy or /rati=m cl\ds--! s-call$ cumulus & /ratus cl\ds & _! _m int]m$iate v>ieties 7see ,frontispiece74 ,?is l[] lay] )9 ! convective zone is1 !re=e1 a moi/ "o ov]laid by a relatively dri] middle lay] ( ! convective zone4 ,t moi/ure :i* rises above ! l[] cl\d lay] is congeal$ by adiabatic cool+ to f9e ice ne$les visible z ! s-call$ cirrus cl\ds :i* float z fea!ry fronds b5ea? ! convective ceil+ 7see frontispiece at "r upp] corn] ( picture74 ,?us we h )9 ! convective zone an upp] lay] m or less *>g$ ) wat] 9 ! =m ( ice ne$les4 ,x is ! cl\ds ( ! l[] zone ^: moi/ure 9 ! =m ( vapor supplies ! n\ri%m5t ( m\nta9 glaci]s1 & ! high cirrus cl\ds ^: congeal$ moi/ure1 aft] int]e/+ trans=mations1 is responsible = ! cont9u$ exi/5ce ( cont95tal glaci]s4 ,z we are to see1 !re are o!r notewor?y diff]5ces betwe5 cont95tal & m\nta9 glaci]s1 9 ! mann] ( _! sculpture ( ! li?osph]e1 s t long aft] !y h disappe>$ ! *>act]s ( ea* are easily id5tifi$ 9 _! h&iwork4 ,h[ ! l[] cl\ds are =c$ upw>d & s compell$ to give up _! moi/ure to fe$ ! m\nta9 glaci]s1 & h[ ! upp] cl\ds are pull$ d[nw>d to n\ri% ! glaci]s ( cont95ts1 c be be/ und]/ood aft] ! *>act]i/ics ( ea* glaci] class h be5 /udi$4 ,,*apt] ,,xxi ,,! ,,cont95tal ,,glaci]s ,,( ,,pol> ,,regions ,illu/ration3 ,,fig4 #bii4--,map ( ,gre5l& %[+ ! area ( inl&-ice & ! r\tes ( diff]5t explor]s4 ,! inl& ice ( ,gre5l&4--,9 ,gre5l& & 9 ,ant>ctica ! l& is almo/ or q buri$ "u a cov] ( sn[ & ice--! s-call$ 8inl& ice0--:i* always assumes ! surface ( a v flat dome or %ield4 ,9 ,gre5l& !re is f\nd a m>g9al ribbon ( l& g5]ally f five to tw5ty-five miles 9 wid? 7,fig4 #bii71 b 9 ,ant>ctica all ! l&1 ) ! exception ( a few m\nta9 peaks1 is inwrapp$ 9 a mantle ( ice :i* is also ext5d$ ^u ! sea 9 a broad %elf ( sn[ & ice4 ,nei!r ( ^! va/ glaci]s has be5 explor$ except 9 its m>g9al portion1 yet su* is ! symmetry ( ! pr(iles along ! r\tes trav]s$1 & su* ! flatness & monotony ( ! sn[ surface )9 ! m>g9s1 t !re is little reason to d\bt t ! pr(ile made along ,nans5's r\te 9 s\!rn ,gre5l& w\ld1 save only = magnitude1 fairly repres5t a section across ! middle ( ! cont95t 7,fig4 #cjj74 ,! m\nta9 ramp>t & its portals4--,z soon z we exam9e ! coa/al belt we obs]ve t ! 8,great ,ice0 ( ,gre5l& is held 9 by a wall ( m\nta9s & s prev5t$ f spread+ out to its natural surface 9 ! m>g9al portions4 ,?r\gh portals ( ! inclos+ m\nta9 ranges--! outlets--x s5ds out tongues ( ice :i* 9 _m respects resemble c]ta9 types ( m\nta9 glaci]s4 ,illu/ration3 ,,fig4 #cjj4--,pr(ile 9 natural proportions across ! s\!rn end ( ! cont95tal glaci] ( ,gre5l&1 con/ruct$ ^u an arc ( ! e>?'s surface & bas$ ^u ,nans5's pr(ile correct$ by ,hess4 ,! m>g9al portions ( ! pr(ile are repres5t$ bel[ ^u a magnifi$ scale 9 ord] to br+ out ! *>act]s ( ! m>g9al slopes4 ,su* measurem5ts z h be5 made ^u ! inl& ice ( ,gre5l& at po9ts back f1 b yet comp>atively ne> to1 ! outlets1 %[ t x has "h a surface rate ( motion am\nt+ to less ?an an in* p] day1 & x is highly probable t at mod]ate di/ances f ! m>g9 ?is am\nt dim9i%es to z]o4 ,^u ! outlets1 on ! contr>y1 surface rates z high z #ei feet p] day h be5 measur$1 & ev5 #ajj feet p] day has be5 report$4 ,we are ?us ju/ifi$ 9 say+ t glaci] fl[ )9 ! outlets is f #gjj to #ajjj times z great z x is ^u ! ne>-by inl& ice1 & t ! glaci] is 9 a measure dra9$ ?r\gh ! portals ( ! inclos+ ranges4 ,back f ^! outlet /reams ( ice1 or tongues1 ! surface ( ! inl& ice is depress$ to =m a dimple or 8bas9 ( exudation0 z is ! surface ( a res]voir above ! raceway :5 ! wat] is be+ rapidly drawn away 7,fig4 #cja74 ,,plate #ac4 ,illu/ration3 ,a4 ,precipit\s front ( ! ,bryant glaci] outlet ( ! ,gre5l& inl&-ice 7aft] ,*amb]l974 ,illu/ration3 ,b4 ,lat]al /ream beside ! ,b5$ict glaci] outlet1 ,gre5l& 7aft] ,r4 ,e4 ,pe>y74 ,illu/ration3 ,,fig4 #cja4--,map ( a glaci] tongue1 ) dimple %[+ above & due to indraught ( ! ice4 ,umanakfjord1 ,gre5l& 7aft] von ,drygalski74 ,fissures 9 ! ice1 ! s-call$ crevasses1 are ! recogniz$ m>ks ( ice movem5t1 & ^! are always conc5trat$ at ! /eep slopes ( ! ice surface 9 ! neighborhood ( its m>g9s4 ,^u ! ,gre5l& ice1 crevasses are re/rict$ 9 _! di/ribution to a zone :i* ext5ds f sev5 to tw5ty-five miles )9 ! ice bord]4 ,! m>g9al rock isl&s4--,f its m>g9 ! ice surface rises s /eeply z to be climb$ only ) difficulty1 b ?is gradi5t /eadily dim9i%es until at a di/ance ( betwe5 sev5ty-five & a hundr$ miles its slope is less ?an two degrees4 ,:]e cross$ by ,nans5 ne> latitude #fd ,n4 ! broad c5tral area ( ice 0 s ne>ly level z to appe> to be a pla94 ,z we pass across ! irregul> ice m>g9 9 ! direction ( ! int]ior1 l>g] & l>g] proportions ( ! l&'s surface are subm]g$1 until only project+ peaks rise above ! ice z isl&s :i* are describ$ z nunataks 7,fig4 #cjb74 ,?\gh n a univ]sal obs]vation1 x has be5 (t5 not$ t ! absorption ( ! sun's rays by rock masses project+ ?r\gh ! sn[ results 9 a radiation ( ! heat & a l[]+ by melt+ ( ! surr\nd+ sn[ & ice4 ,= ?is reason nunataks are (t5 surr\nd$ by a deep tr5* due to a melt+ ( ! sn[4 ,su* a depression 9 ! ice surface ab\t ! m>g9 ( a nunatak1 f its resemblance to a tr5* ab\t an anci5t ca/le1 has be5 designat$ a moat 7,fig4 #cjc74 ,= ! same reason1 ! outlet tongues ( ice :i* desc5d 9 deep fjords betwe5 walls ( rock are melt$ away f ! walls & a lat]al /ream ( wat] is sometimes f\nd to fl[ betwe5 ice & rock 7pl4 #ac ,b74 ,illu/ration3 ,,fig4 #cjb4--;,edge ( ! ,gre5l& inl& ice1 %[+ ! nunataks dim9i%+ 9 size t[>d ! int]ior4 ,! l9es ^u ! ice are m$ial mora9es />t+ f nunataks 7aft] ,libbey74 ,rock fragm5ts :i* travel ) ! ice4--,rock surfaces :i* are expos$ to ! atmosph]e are 9 high latitudes brok5 d[n ?r\gh ! freez+ ( wat] )9 _! crevices4 ,! fragm5ts result+ f ?is r5d+ process fall ^u ! glaci] surface & are c>ri$ =w>d z pass5g]s 9 ! direction ( ! ice m>g94 ,!y are ei!r visible z long & n>r[ ridges or tra9s foll[+ ! directions ( ! /eepe/ slope 7,fig4 #cjb71 or !y become buri$ "u fre% falls ( sn[ & only aga9 become visible :]e summ] melt+ has l[]$ ! glaci] surface 9 ! vic9ity ( its m>g94 ,^! longitud9al tra9s ( rock fragm5ts ^u ! glaci] surface always h _! />t+ po9t at ! l[] m>g9 ( "o ( ! nunataks1 & are kn[n z m$ial mora9es 7,fig4 #cja1 p4 #bgc1 & ,fig4 #cjb74 ,inside ! zone ( nunataks ! glaci] surface is1 h[ev]1 cle> ( rock dbris except :]e du/ has be5 bl[n on by ! w9d1 & ?is ext5ds = a few miles only4 ,! mat]ial ( ! m$ial mora9es is a collection ( angul> blocks ^: surfaces are ! result ( fro/ r5d+1 = 9 _! travel above ! ice !y are subject$ to no abrad+ processes4 ,illu/ration3 ,,fig4 #cjc4--,moat surr\nd+ a nunatak 9 ,victoria ,l& 7aft] ,scott74 ,a contra/$ type ( surface mora9es ^u ! ,gre5l& glaci]1 in/ead ( be+ p>allel to ! direction ( ice movem5t1 is direct$ transv]sely or p>allel to ! m>g9s4 ,! mat]ials ( ^! mora9es are m r\nd$ fragm5ts ( rock :i* h come up f ! bottom lay]s1 & we %all aga9 ref] to ! orig9 ( su* mora9es aft] ! subglacial conditions h be5 consid]$4 ,! gr9d+ mill b5ea? ! ice4--,if1 n[1 we exam9e ! front ( a glaci] tongue :i* goes out f ! inl& ice1 we f9d t :ile ! upp] portion is :ite & ma9ly free f rock dbris 7plate #ac ,a71 ! l[] zone is ( a d>k color & cr[d$ ) lay]s ( pebbles & b[ld]s :i* h be5 plan$1 poli%$1 & scrat*$ 9 a q rem>kable mann]4 ,! ice front is itself subject to =w>d & retrograde migrations ( %ort p]iod1 b x is easily se5 t 9 ! ma9 its l>g] movem5t has be5 a retrograde "o4 ,! gr\nd f :i* x has lately )drawn is g5]ally a h>d rock floor unwea!r$1 b smoo?1 poli%$1 & scrat*$ 9 ! same mann] z ! b[ld]s :i* are imb$d$ )9 ! ice4 ,x is p]fectly app>5t t ! latt] h be5 d]iv$ f "s portion ( ! rock basem5t ^u :i* ! glaci] /ill re/s1 & t floor & b[ld]s h alike be5 gr\nd smoo? by mutual contact "u pressure4 ,?is erosion b5ea? ! ice is accompli%$ by two processes2 namely1 pluck+ & abrasion4 ,:]ev] ! rock ov] :i* ! glaci] moves has /ood up 9 project+ masses & is riv5 by fissure planes ( any k9d1 ! ice has f\nd x easy to remove x 9 l>g] or small] fragm5ts by a qu>ry+ process describ$ z pluck+4 ,! rock may be said to be torn away 9 blocks :i* are l>gely b\nd$ by ! prexi/+ fissure planes4 ,ov] relatively ev5 surfaces pluck+ has little importance1 b :]e !re are notewor?y inequalities ( surface ^u ! glaci] b$1 ^? sides :i* are away f ! oncom+ ice 7lee side7 are degrad$ by pluck+ 9 su* a mann] z sometimes to leave /eep & ragg$ fracture surfaces4 ,! tools ( ! ice ?us acquir$ 9 ! process ( pluck+ are quickly froz5 into ! l[e/ ice lay]s1 & be+ n[ dragg$ along ! floor !y abrade 9 ! same mann] z does a rasp or file4 ,^! tools ( ! ice are !mselves worn away 9 ! process & are ?us giv5 _! *>act]i/ic %apes4 ,j z ! lapid>y gr9ds ! surface ( a jewel into facets by imb$d+ ! gem 9 a matrix1 fir/ 9 "o & !n 9 ano!r position1 ea* "t we>+ d[n ! project+ irregul>ities ?r\gh contact ) ! abrad+ surface2 s 9 l mann] ! rock fragm5t is held fa/ at ! bottom ( ! glaci] until 8sol$0 or 8%od01 fir/ ^u "o side & !n ^u ano!r4 ,accid5tal contact ) "s ob/ruction ^u ! floor may suffice to turn ! fragm5t & s expose a new surface to we> ^u ! abrad+ floor4 ,m9or ob/ructions com+ 9 contact ) "o side ( ! fragm5t only1 may turn x 9 its own plane )\t ov]turn+4 ,evid5ce ( su* int]ruptions c be lat] read 9 ! diff]5t directions ( /ri ^u ! same facet 7plate #ag ,a74 ,illu/ration3 ,,fig4 #cjd4--;,a glaci] pavem5t ( ,p]mo-,c>bonif]\s age 9 ,s\? ,africa4 ,! /ri runn+ 9 ! direction ( ! obs]v] are prom95t & a notewor?y g\g+ ( ! surface is to be not$ to ! "r 9 ! middle di/ance 7aft] ,davis74 ,! floor b5ea? ! glaci] is r$uc$ by ! abrad+ process to a m or less smoo? & g5]ally flatt5$ or r\nd$ surface--! s-call$ glaci] pavem5t 7,fig4 #cjd74 ,to accompli% ?is all =m] mantle rock due to wea!r+ processes mu/ fir/ be cle>$ away1 & ! firm unalt]$ rock b5ea? is :]ev] susceptible ( x giv5 a smoo? poli% al?\gh locally scor$ & scrat*$ by ! gr9d+ b[ld]s4 ,! e>li] projections ( ! surface ( ! floor1 if n entirely plan$ away1 are at lea/ trans=m$ into r\nd$ %\ld]s ( rock1 :i* f _! resemblance to closely cr[d$ backs 9 a flock ( %eep h be5 call$ 8%eep backs0 or 8ro*es m\tonnes40 ,?us ! effect ( ! comb9$ action ( ! processes ( pluck+ & abrasion is to r$uce ! acc5t ( ! relief & to mold ! cont\rs ( ! rock 9 smoo?ly fl[+ curves1 g5]ally ( l>ge radius4 ,! lift+ ( ! gr9d+ tools & _! incorporation )9 ! ice4--,:]ev] ! ice is locally held 9 *eck by ! project+ nunataks1 relief is f\nd betwe5 su* ob/ructions1 & !re ! fl[ ( ! ice has a correspond+ly increas$ velocity 7,fig4 #cje b74 ,if ! ob/ructions are n ( l>ge dim5sions1 ! ice :i* fl[s ar\nd ! out] edges is soon jo9$ to t :i* passes betwe5 ! ob/ructions & s normal conditions ( fl[ are re/or$ bel[ ! nunataks4 ,! locally rapid fl[ ( ! ice is1 !re=e1 re/rict$ to a relatively %ort di/ance1 ! passageway betwe5 ! nunataks1 & ! conditions are ?us to be lik5$ to ! fall ( wat] at a raceway due to ! sudd5 desc5t ( its surface f ! level ( ! res]voir to ! level ( ! /ream 9 ! outlet4 ,z is well kn[n1 !re is "u ^! conditions a prodigi\s sc\r ^u ! bottom :i* t5ds to dig a pit j above & bel[ ! dam--a scape colk--& c>ry ! mat]ials up to ! surface bel[ ! pit4 ,su* a t5d5cy 0 well illu/rat$ by ! behavior ( ! wat] at ! op5+ ( ! ,neu ,hauf5 dam bel[ ! city ( ,vi5na 7,fig4 #cje a74 ,9 ! case ( ice1 mat]ial f ! bottom may by ! upw>d curr5t be br\ght up to ! surface ( ! glaci] at ! l[] edge ( ! colk & ?us produce a type ( local surface mora9e ( horse%oe =m ) its direction g5]ally transv]se to ! direction ( ice movem5t 7,fig4 #cje b74 ,illu/ration3 ,,fig4 #cje4--;a1 ,map %[+ pit excavat$ by ! curr5t bel[ ! op5+ 9 a dam4 b1 ,nunataks & surface mora9es on ! ,gre5l& ice4 ,dalag]'s ,nunataks 7aft] ,suess74 ,any ob/ruction ^u ! pavem5t ( ! glaci] app>5tly ex]ts a l>g] or small] t5d5cy to elevate ! b[ld]s & pebbles & incorporate !m )9 ! ice4 ,rock dbris ?us incorporat$ is describ$ z englacial drift4 ,9 ! case ( ,gre5l& glaci]s ?is mat]ial seems at ! ice front to be l>gely re/rict$ to ! l[] #ajj feet 7plate #ac ,a74 ,ne> ! front ( ! inl& ice ! increas$ slope ( ! upp] surface greatly increases ! fl[ ( ! upp] ice lay]s 9 comp>ison ) ^? ne>] ! bottom1 s t ! upp] lay]s ov]ride ! l[] z !y w\ld an ob/ruction4 ,! englacial drift is ei!r = ?is reason or because ( rock ob/ructions br\ght to ! surface1 :]e x yields p>allel ridges correspond+ 9 direction to ! glaci] m>g94 ,su* transv]se surface mora9es are ?us 9 _m respects analog\s to ^? :i* appe> ab\t ! l[] m>g9s ( scape colks4 ,9 contra/ to ! longitud9al or m$ial surface mora9es ! mat]ials ( ! transv]se mora9es are m facet$ & r\nd$--!y h be5 abrad$ ^u ! glaci] pavem5t4 ,melt+ ^u ! glaci] m>g9s 9 ,gre5l&4--,dur+ ! %ort b w>m summ] season1 ! m>g9s ( ! ,gre5l& ice are subject to consid]able losses ?r\gh surface melt+4 ,:5 ! upp]mo/ ice lay] has atta9$ a temp]ature ( #cb ,fahr5heit1 melt+ beg9s & moves rapidly inw>d f ! glaci] m>g94 ,9 late spr+ ! surface ( ! out] m>g9al zone is saturat$ ) wat]1 & ?is zone ( slu% advances inw>d ) ! season1 b app>5tly nev] transgresses ! inn] bord] ( :at we h g5]ally ref]r$ to z ! m>g9al zone ( ! ice *>act]iz$ by relatively /eep slopes1 crevasses1 & nunataks4 ,^u ! ice )9 ?is zone are f\nd /reams l>ge en\gh to be designat$ z riv]s & ^! are connect$ ) pools1 lakes1 & morasses4 ,! dirt & rock fragm5ts imb$d$ 9 ! ice are melt$ out 9 ! l[]+ ( ! surface1 s t late 9 ! season ! ice pres5ts a mo/ dirty aspect4 ,at ! front ( ! great m\nta9 glaci]s ( ,alaska1 a m vigor\s op]ation ( ! same process has yield$ a surface soil 9 :i* gr[ su* rank =e/s z entirely to mask ! pres5ce ( ! ice b5ea?4 ,9 addition to ! visible /reams ^u ! surface ( ! ,gre5l& ice1 !re are o!rs :i* fl[ b5ea? & c be he>d by putt+ ! e> to ! surface4 ,all surface /reams ev5tually enc\nt] ! m>g9al crevasses & plunge d[n 9 foam+ cascades1 produc+ ! well kn[n 8glaci] wells0 or 8glaci] mills40 ,! progress ( ! wat] is n[ ?r\gh\t 9 tunnels )9 ! ice until x aga9 makes its appe>ance at ! glaci] m>g94 ,illu/ration3 ,,fig4 #cjf4--,m>g9al mora9e n[ =m+ at ! edge ( ,gre5l& inl& ice1 %[+ a smoo? rock pavem5t outside x4 ,a small lake ) a p>tial cov]+ ( lake ice occupies a holl[ ( ?is pavem5t 7aft] von ,drygalski74 ,! m>g9al mora9es4--,/udy ( bo? ! ,gre5l& & ,ant>ctic glaci]s has %[n t if we disreg>d ! small] & %ort-p]iod migrations ( ! ice front1 ! g5]al lat] movem5t has be5 a retrograde "o--we live 9 a rec$+ hemicycle ( glaciation4 ,! e>li] ,gre5l& glaci] has n[ rec$$ s z to expose l>ge areas ( ! =m] glaci] pavem5t4 ,9 places ?is pavem5t is l>gely b>e1 indicat+ a relatively rapid retirem5t ( ! ice front1 b at all po9ts at :i* ! ice m>g9 0 halt$ !re is n[ f\nd a ridge ( unassort$ rock mat]ials :i* 7 dropp$ by ! ice z x melt$ 7,fig4 #cjf74 ,su* ridges1 compos$ ( ! unassort$ mat]ials describ$ z till1 come to h a fe/oon$ arrangem5t l>gely conc5tric to ! ice m>g91 & are ! m>g9al or t]m9al mora9es 7see ,fig4 #ccf1 p4 #cab74 ,m>g9al mora9es1 if ( l>ge dim5sions1 usually h a hummocky surface1 & are apt to be compos$ ( rock fragm5ts ( a wide range ( size f rock fl\r 7clay7 to l>ge b[ld]s 7plate #ag ,a71 :i* may repres5t _m types s9ce !y h be5 pluck$ by ! glaci] or ga!r$ 9 at its surface f _m widely sep>at$ localities4 ,illu/ration3 ,,fig4 #cjg4--,small lake imp\nd$ betwe5 ! ice front & a mora9e :i* x has rec5tly built4 ,gre5l& 7aft] von ,drygalski74 ,z ! glaci] front retires f ! mora9e :i* x has built up1 ! wat] :i* em]ges f b5ea? ! ice is imp\nd$ beh9d ! new dam s z to =m a lake ( cresc5tic outl9e 7,fig4 #cjg74 ,su* lakes are p>ticul>ly %ort-liv$1 = ! reason t ! wat] f9ds an outlet ov] ! l[e/ po9t 9 ! cre/ ( ! mora9e & easily cuts a gorge ?r\gh ! loose mat]ials1 ?us dra9+ ! lake 7,fig4 #cjh74 ,!reaft]1 ! escap+ wat] fl[s 9 a braid$ /ream across ! late lake bottom & !nce at ! bottom ( ! gorge ?r\gh ! mora9e4 ,illu/ration3 ,,fig4 #cjh4--,view ( a dra9$ lake bottom betwe5 ! mora9e-cov]$ ice front 9 ! =egr\nd & an ab&on$ m>g9al mora9e 9 ! middle di/ance4 ,! wat] fl[s f ! ice front 9 a braid$ /ream & passes out ?r\gh ! mora9e 9 a n>r[ gorge4 ,v>iegat$ glaci]1 ,alaska 7aft] ,lawr5ce ,m>t974 ,! outwa% pla9 or apron4--,! wat] :i* desc5ds f ! glaci] surface 9 ! glaci] wells or mills1 ev5tually arrives at ! bottom1 :]e x foll[s a s9u\s c\rse )9 a tunnel melt$ out 9 ! ice4 ,mu* ( ?is wat] may issue at ! ice front b5ea? ! co>se rock mat]ials :i* are f\nd !re1 & s be discov]$ ) ! e> r ?an by ! eye4 ,! wat] )9 ! tunnels n fl[+ ) a free surface b be+ conf9$ z ?\gh x 7 9 a pipe1 may1 h[ev]1 rea* ! glaci] m>g9 "u a hydro/atic pressure suffici5t to c>ry x up ris+ grades4 ,inasmu* z x is heavily *>g$ ) rock dbris & is sudd5ly *eck$ ^u arriv+ at ! front x deposits its burd5 ab\t ! ice m>g9 s z to build up pla9s ( assort$ s&s & gravels1 & ov] ?is surface x fl[s 9 ev] %ift+ s]p5t9e *annels ( braid$ type 7,fig4 #cjh74 ,su* pla9s ( glaci] outwa% are describ$ z outwa% pla9s or outwa% aprons4 ,ris+ z x does "u hydro/atic pressure ! wat] issu+ at ! glaci] front may f9d its way upw>d 9 "s ( ! crevasses & s em]ge at a level consid]ably above ! glacial floor4 ,x may ?us come ab\t t ! outwa% pla9 is built up ab\t ! nose ( ! glaci] s z p>tially to bury x f sight4 ,:5 n[ ! ice front beg9s a rapid retirem5t1 a depression or fosse 7,fig4 #cji & ,fig4 #cci1 p4 #cad7 is left beh9d ! outwa% pla9 & 9 front ( ! mora9e :i* is built up at ! next halt+ place4 ,illu/ration3 ,,fig4 #cji4--;,diagrams to %[ ! mann] ( =mation & ! /ructure ( an outwa% pla91 & ! position ( ! fosse betwe5 ?is & ! mora9e4 ,! cont95tal glaci] ( ,ant>ctica4--,9 ,victoria ,l&1 ^u ! cont95t ( ,ant>ctica1 s f> z exploration has yet gone1 ! cont95tal glaci] is held back by a ramp>t ( m\nta9s1 z has be5 %[n to be true ( ! inl& ice ( ,gre5l&4 ,! same flat dome or %ield has likewise be5 f\nd to *>act]ize its upp] surface 7,fig4 #caj74 ,! mo/ notewor?y diff]5ces betwe5 ! inl& ice masses ( ,gre5l& & ,ant>ctica are to be ascrib$ to ! great] sev]ity ( ! ,ant>ctic climate & to ! m ample n\ri%m5t ( ! s\!rn glaci] measur$ by ! l& area :i* x has subm]g$4 ,!re is "h no m>g9al l& ribbon z 9 ,gre5l&1 b ! glaci] cov]s all ! l& & is1 moreov]1 ext5d$ ^u ! sea z a broad float+ t]race--! %elf ice 7,fig4 #caa74 ,?is b>ri] at its m>g9 puts a b> to all fur!r navigation1 ris+ z x does 9 "s cases #bhj feet above ! sea & desc5d+ to ev5 great] dep?s bel[ 7plate #ae ,b74 ,illu/ration3 ,,fig4 #caj4--,map %[+ ! inl& ice ( ,victoria ,l& bord]$ by ! %elf ice ( ! ,great ,ross ,b>ri]4 ,! arr[s %[ ! direction ( ! prevail+ w9ds 7bas$ on maps by ,scott & ,%ackleton74 ,9 t portion ( ,ant>ctica :i* 0 explor$ by ! ,g]man exp$ition1 ! inl& ice is n z 9 ,victoria ,l& re/ra9$ )9 walls ( rock1 b is spread out ^u ! cont95t s z to assume its natural ice slopes1 :i* are !re=e mu* flatt] ?an ^? exam9$ 9 ,gre5l& & ,victoria ,l&4 ,"h 9 ,kais] ,wilhelm ,l& ! ice rises at its sea m>g9 9 a cliff :i* is f #acj to #afe feet 9 height1 !n ^u a fairly /eeply curv+ slope to an elevation ( p]haps a ?\s& feet4 ,"h ! grades h become relatively level1 & on ev] flatt] slopes ! surface appe>s to cont9ue into ! di/ant int]ior 7plate #ad74 ,ne> ! ice m>g9 num]\s fissures betray a motion )9 ! mass :i* exact measurem5ts indicate to be b "o foot p] day1 & at a di/ance ( a mile & a qu>t] f ! m>g9 ev5 ?is slight value has dim9i%$ by fully "o eigh?4 ,x c h>dly be d\bt$ t at mod]ate di/ances only )9 ! ice m>g91 ! glaci] is practically )\t motion4 ,,plate #ad4 ,illu/ration3 ,view ( ! m>g9 ( ! ,ant>ctic cont95tal glaci] 9 ,kais] ,wilhelm ,l& 7aft] ,e4 v4 ,drygalski74 ,ra9 or g5]al melt+ conditions be+ unkn[n 9 ,ant>ctica1 a /rik+ contra/ is (f]$ to ! m>g9al zone ( ! ,gre5l& cont95t4 ,?is is to a l>ge ext5t expla9$ by ! exi/5ce ^u ! nor!rn l& mass ( a coa/l& ribbon :i* becomes quickly heat$ 9 ! sun's rays1 & bo? by w>m+ ! air & by radiat+ heat to ! ice x causes melt+ & produces local air temp]atures :i* 9 summ] may ev5 be describ$ z hot4 ,ab\t ,indep5d5ce ,bay 9 latitude #hb ,n4 & ne> ! nor!rnmo/ extremity ( ,gre5l&1 ,pe>y desc5d$ f ! inl& ice into a little valley )9 :i* musk ox5 7 lazily graz+ & :]e bees buzz$ f blossom to blossom ov] a gorge\s c>pet ( fl[]s4 ,illu/ration3 ,,fig4 #caa4--,sections across ! inl& ice ( ,victoria ,l&1 ,ant>ctica1 ) ! %elf ice 9 front 7aft] ,%ackleton74 ,n\ri%m5t ( cont95tal glaci]s4--,explorations ^u & ab\t ! glaci]s ( ,gre5l& & ,ant>ctica h %[n t ! circulation ( air above ^! va/ ice %ields con=ms to a q simple & symmetrical model subject to spasmodic pulsations ( a v pron\nc$ type4 ,ea* great ice mass ) its atmosph]ic cov] con/itutes a sort ( refrig]at+ air eng9e & plays an important "p 9 ! w9d sy/em ( ! globe4 7,see ,fig4 #bia1 p4 #bfc74 ,bo? ! dom$ surface & ! l[ temp]ature ( ! glaci] are ess5tial to ! cont9uation ( ?is pulsat+ movem5t )9 ! atmosph]e 7,fig4 #cab74 ,! air lay] 9 contact ) ! ice is dur+ a p]iod ( calm cool$1 contract$1 & r5d]$ heavi]1 s t x beg9s to slide d[nw>d & outw>d ^u ! dom$ surface 9 all directions4 ,! extreme flatness ( ! great] portion ( ! glaci] surface--a fraction only ( "o degree--makes ! eng9e extremely sl[ 9 />t+1 b l all bodies :i* slide ^u incl9$ planes1 ! velocity ( its movem5t is rapidly accel]at$1 until a blizz>d is develop$ ^: vigor is unsurpass$ by any else:]e exp]i5c$4 ,illu/ration3 ,,fig4 #cab4--;,diagram to %[ ! nature ( ! fix$ glacial anticyclone above cont95tal glaci]s & ! process by :i* _! surface is %ap$4 ,! effect ( su* c5trifugal air curr5ts above ! glaci] is to suck d[n ! air ( ! upp] curr5ts 9 ord] to supply ! void :i* soon t5ds to develop ov] ! c5tral portion ( ! glaci] dome4 ,?is d[nw>d vortex1 f$ z x is by inw>d-bl[+1 high-level curr5ts1 & dra9$ by outw>dly direct$ surface curr5ts1 is :at is kn[n z an anticyclone1 "h fix$ 9 position by ! c5tral embossm5t ( ! dome4 ,! air :i* desc5ds 9 ! c5tral column is w>m$ by compression1 or adiabatically1 j z air is w>m$ :i* is =c$ into a rubb] tire by ! use ( a pump4 ,! moi/ure congeal$ 9 ! cirrus cl\ds float+ 9 ! upp]mo/ lay] ( ! convective zone1 is c>ri$ d[n 9 ?is vortex & fir/ melt$ & 9 turn evaporat$1 due to ! adiabatic effect4 ,?is fusion & evaporation ( ! ice by its trans=mation ( lat5t1 to s5sible1 heat1 9 a measure c\nt]acts1 & s ret>ds1 ! adiabatic elevation ( temp]ature )9 ! column4 ,ev5tually ! w>m air n[ *>g$ ) wat] vapor rea*es ! ice surface1 is at once *ill$1 & its burd5 ( moi/ure precipitat$ 9 ! =m ( f9e sn[ ne$les1 ! s-call$ 8fro/ sn[01 :i* 9 accompanim5t to ! sudd5 elevation ( temp]ature is precipitat$ at ! t]m9ation ( a blizz>d4 ,! w>m+ ( ! air has1 h[ev]1 _h ! effect ( damp+ z x 71 ! eng9e /roke1 &1 z ! process is cont9u$1 to />t a rev]se or upw>d curr5t )9 ! *imney ( ! anticyclone4 ,! blizz>d is ?us sudd5ly end$ 9 a precipitation ( ! sn[1 :i* by *ang+ ! lat5t heat ( cond5sation to s5sible heat t5ds to increase ?is c\nt] curr5t4 ,illu/ration3 ,,fig4 #cac4--,sn[ deltas ab\t ! m>g9s ( ! ,fan glaci] outlet ( ,gre5l& 7aft] ,*amb]l974 ,! glaci] broom4--,dur+ ! calm :i* succe$s to ! blizz>d1 heat is once m ab/ract$ f ! surface air lay]1 & a new outw>dly direct$ eng9e /roke is begun4 ,! tempe/ :i* lat] develops acts z a gigantic c5trifugal broom :i* sweeps out to ! m>g9s ( ! glaci] all portions ( ! late/ sn[fall :i* h n become firmly atta*$ to ! ice surface4 ,! sweep+s pil$ up ab\t ! m>g9 ( cont95tal glaci]s h be5 describ$ z fr++ glaci]s1 or ! glacial fr+e4 ,! nor!rn coa/ ( ,gre5l& & ,grant ,l& are bord]$ by a fr+e ( ?is nature 7plate #ad ,a1 & ,fig4 #cae1 p4 #bhh74 ,x is by ! op]ation ( ! glaci] broom t ! inl& ice is giv5 its *>act]i/ic %ield-l %ape 7,fig4 #cab74 ,! granul> nature ( ! sn[ c>ri$ by ! w9d is well br\ght out by ! little sn[ deltas ab\t ! m>g9s ( ,gre5l& ice tongues 7,fig4 #cac74 ,obvi\sly because ( ! pres5ce ( ! vigor\s anticyclone1 no sn[s su* z n\ri% m\nta9 glaci]s c be precipitat$ ^u cont95tal glaci]s except )9 a n>r[ m>g9al zone1 &1 z %[n by ,nans5 rock du/ f ! coa/l& ribbon & f ! nunataks ( ,gre5l&1 is c>ri$ by a few miles inside ! we/]n m>g91 & n at all )9 ! ea/]n4 ,illu/ration3 ,,fig4 #cad4--,sea ice ( ! ,arctic region 9 lat4 #hj #e ,n4 & long4 #b #eb ,e4 7aft] ,duc d',orleans74 ,field & pack ice4--,)9 pol> regions ! surface ( ! sea freezes dur+ ! long w9t] season1 ! product be+ kn[n z sea-ice or field-ice 7,fig4 #cad74 ,?is ice cov] may rea* a ?ickness by direct freez+ ( eight or m feet1 & by break+ up & be+ cr[d$ above & bel[ neighbor+ fragm5ts may increase to a consid]ably great] ?ickness4 ,ice ?us cr[d$ toge!r & m or less cru%$ is describ$ z pack ice or ! pack4 ,! pack does n rema9 /ation>y b is cont9ually drift+ ) ! w9d & tide1 fir/ 9 "o direction & !n 9 ano!r1 b ) a g5]al drift 9 ! direction ( ! prevail+ w9ds4 ,because ( ! va/ dim5sions ( ! pack1 ! w9ds ov] widely sep>at$ p>ts may be contr>y 9 direction1 & h5ce :5 curr5ts bl[ t[>d ea* o!r or :5 ! ice is =c$ aga9/ a l& area1 x is locally cru%$ "u mighty pressures & =c$ up into l9es ( hummocks--! s-call$ pressure ridges4 ,at o!r times1 :5 ! w9ds ( widely sep>at$ areas bl[ away f ea* o!r1 ! pack is p>t$1 ) ! =mation ( lanes or leads ( op5 wat]4 ,if se5 9 bird's-eye view ! l9es ( hummocks w\ld accord+ to ,nans5 be arrang$ l ! me%es ( a net hav+ r\ghly squ>$ angles & rea*+ to heights ( #ae to #be1 r>ely #cj1 feet above ! g5]al surface ( ! pack4 ,! ice )9 ea* me% ( ! network is a floe1 :i* at ! times ( pressure is gr\nd aga9/ its neighbors & v>i\sly %ift$ 9 position4 ,at ! m>g9 ( ! pack ^! floes become sep>at$ & float t[>d l[] latitudes until !y are melt$4 ,! drift ( ! pack4--,! discov]y ( ! drift 9 ! ,arctic pack is a romantic *apt] 9 ! hi/ory ( pol> exploration1 & has furni%$ an example ( fai? 9 sci5tific reason+ & judgm5t :i* may well be comp>$ ) t ( ,columbus4 ,! great figure 9 ?is lat] discov]y is ! ,norwegian explor] ,fridtj( ,nans51 & to ! f9al a*ievem5t ! ill-fat$ ,jeannette exp$ition contribut$ an important "p4 ,! ,jeannette c>ry+ ! ,am]ican explor+ exp$ition 0 9 #ahgi caught 9 ! pack to ! nor?w>d ( ,wrangel ,isl& 7,fig4 #cae71 & two ye>s lat] 0 cru%$ by ! ice & sunk to ! nor?w>d ( ! ,new ,sib]ian ,isl&s4 ,9 #ahhd v>i\s articles1 includ+ a li/ ( /ores 9 ! h&writ+ ( ! comm&] ( ! ,jeannette1 7 pick$ up at ,julianehaab ne> ! s\!rn extremity ( ,gre5l& b ^u ! we/]n side ( ,cape ,f>ewell4 ,nans51 hav+ c>efully v]ifi$ ! facts1 conclud$ t ! recov]$ articles c\ld h f\nd _! way to ,julianehaab only by drift+ 9 ! pack across ! pol> sea1 & t at ! longe/ only five ye>s _h be5 consum$ 9 ! transit4 ,aft] be+ sep>at$ f ! pack ! articles mu/ h float$ 9 ! curr5t :i* makes s\?w>d along ! ea/ coa/ ( ,gre5l& & aft] d\bl+ ,cape ,f>ewell fl[s nor?w>d ^u ! we/ coa/4 ,x 0 cle> t if !y _h come ?r\gh ,smi? ,s\nd !y w\ld inevitably h be5 f\nd ^u ! o!r %ore ( ,baff9 ,bay4 ,9 confirmation ( ?is view !re 0 f\nd at ,god?aab1 a %ort di/ance to ! nor?w>d ( ,julianehaab 7,fig4 #cae71 an ornam5t$ ,alaskan 8?r[+ /ick0 :i* probably came by ! same r\te4 ,moreov]1 l>ge quantities ( driftwood rea* ! %ores ( ,gre5l& :i* h cle>ly come f ! ,sib]ian coa/1 s9ce ! ,sib]ian l>* has furni%$ ! l>g] quantity4 ,illu/ration3 ,,fig4 #cae4--,map ( ! nor? pol> regions1 %[+ ! area ( drift ice & ! tracks ( ! ,jeannette & ! ,fram 7compil$ f v>i\s maps74 ,p9n+ 8 fai? to ^! indubitable facts1 ,nans5 built ! ,fram 9 su* a mann] z to resi/ & elude ! enorm\s pressures ( ! ice pack1 /ock$ h] ) provisions suffici5t = five ye>s1 & by all[+ ! vessel to be froz5 into ! pack nor? ( ! ,new ,sib]ian ,isl&s1 he consign$ himself & 8 companions to ! m]cy ( ! elem5ts4 ,! _w kn[s ! result z "o ( ! mo/ rem>kable a*ievem5ts 9 ! long hi/ory ( pol> exploration4 ,! track ( ! ,fram1 *>t$ 9 ,fig4 #cae1 consid]$ 9 connection ) t ( ! ,jeannette1 %[s t ! ,arctic pack drifts f ,b]+ ,sea we/w>d until ne> ! nor!a/]n coa/ ( ,gre5l&4 ,special casks 7 = exp]im5tal purposes fa/5$ 9 ! ice to ! nor? ( ,behr+ ,/rait by ,melville & ,bryant1 & two ( ^! 7 aft]w>ds recov]$1 ! "o ne> ! ,nor? ,cape 9 nor!rn ,norway1 & ! o!r 9 nor!a/]n ,icel& 7see map1 ,fig4 #cae74 ,pe>y's trips nor?w>d 9 #aijf & #aiji f ! vic9ity ( ,smi? ,s\nd h indicat$ t betwe5 ! ,pole & ! %ores ( ,gre5l& & ,grant ,l& ! drift is ?r\gh\t to ! ea/w>d1 correspond+ to ! we/]ly w9d4 ,^u ?is bord] ! great area ( ,arctic drift ice is 9 contact ) great cont95tal glaci]s bord]$ by a glaci] fr+e4 ,admiral ,pe>y has %[n t in/ead ( consi/+ ( froz5 sea ice1 ! pack is "h made up ( great floes f #bj to #ajj feet 9 ?ickness & t ^! h be5 d]iv$ f ! glaci] fr+e4 ,:5ev] ! blizz>ds bl[ (f ! inl& ice f ! s\?1 leads are op5$ at ! m>g9 ( ! fr+e & may c>ry /rips f ! latt] nor?w>d across ! lead4 ,) favorable conditions ^! leads may be clos$ by ?ick sea ice s t ) ! occurr5ce ( c\nt] w9ds f ! nor? !y d n entirely return to _! orig9al position4 ,a cont9uance ( ?is process may h result$ 9 ! heavy floe ice to ! nor?w>d ( ,gre5l&1 :i*1 act+ z an ob/ruction1 may h =c$ ! ?9n] drift ice to keep on ! ,european side ( ! ,arctic pack4 ,illu/ration3 ,,fig4 #caf4--,! %elf ice ( ,coats ,l& ) ! surr\nd+ pack ice %[+ 9 ! =egr\nd 7aft] ,bruce74 ,ab\t ! ,ant>ctic cont95t !re is a broad girdle ( pack ice :i*1 :ile m indol5t 9 its movem5ts ?an ! ,arctic pack1 has be5 %[n by ! exp$itions ( ! ,belgica & ! ,p\rquoi-,pas to possess ! same k9d ( %ift+ movem5ts4 ,9 ! s\!rn spr+ ?is pack floats nor?w>d & is to a l>ge ext5t brok5 up & melt$ on rea*+ l[] latitudes4 ,illu/ration3 ,,fig4 #cag4--,tidewat] cliff at ! front ( a glaci] tongue f :i* iceb]gs are born4 ,! ,ant>ctic %elf ice4--,x has be5 already po9t$ out t ! inl& ice ( ,ant>ctica is 9 "p at lea/ surr\nd$ by a ?ick sn[ & ice t]race float+ ^u ! sea & ris+ to heights ( m ?an #aej feet above x 7plate #ae ,b & ,fig4 #caf74 ,! visible portions ( ?is %elf-ice are ( /ratifi$ compact sn[1 & ! areas :i* h ?us f> be5 /udi$ are f\nd 9 bays f :i* dislodgm5t is less easily effect$4 ,! orig9 ( ! %elf ice is believ$ to be a sea-ice :i* because n easily deta*$ at ! "t ( ! spr+ 8break-up0 is ?ick5$ 9 succe$+ seasons *iefly by ! deposition ( precipitat$ & drift$ sn[ ^u its surface1 s t x is b[$ d[n "u ! weight & sunk to great] & great] dep?s 9 ! wat]4 ,to "s ext5t1 also1 x is f$ ^u its inn] m>g9 by ov]fl[ ( glaci] ice f ! inl& ice masses4 ,iceb]gs & sn[b]gs & ! mann] ( _! bir?4--,gre5l& reveals 9 ! "* ( its valleys ! m>ks ( a l>ge subsid5ce ( ! cont95t--! s]p5t9e inlets or fjords by :i* its coa/ is s deeply ind5t$4 ,into ! heads ( ^! fjords ! tongues f ! inl& ice desc5d g5]ally to ! sea level & bel[4 ,! glaci] ice is ?us directly attack$ by ! waves z well z melt$ 9 ! wat]1 s t x t]m9ates 9 ! fjords 9 great cliffs ( ice 7,fig4 #cag74 ,x is also believ$ to ext5d b5ea? ! wat] surface z a long toe re/+ ^u ! bottom 7,fig4 #cai74 ,,plate #ae4 ,illu/ration3 ,a4 ,an ,ant>ctic ice foot ) boat p>ty l&+ 7aft] ,r4 ,f4 ,scott74 ,illu/ration3 ,b4 ,a ne> view ( ! front ( ! ,great ,ross ,b>ri]1 ,ant>ctica 7aft] ,r4 ,f4 ,scott74 ,illu/ration3 ,,fig4 #cah4--;,a ,gre5l&ic iceb]g aft] a long j\rney 9 w>m latitudes4 ,! expos$ cliff is not*$ & und]cut by ! waves 9 ! same mann] z a rock cliff1 & ! upp] portions ov]ride ! l[] s t at frequ5t int]vals small masses ( ice f ?is front sep>ate on crevasses1 & toppl+ ov]1 fall into ! wat] ) picturesque spla%es4 ,su* small b]gs1 ^: bir? may be (t5 se5 at ! cliff front ( bo? ! ,gre5l& & ,alaskan glaci]s1 h little 9 common ) ^? great float+ isl&s ( ice t are drift$ by ! w9ds until1 wa/$ to a fraction only ( _! =m] proportions1 !y rea* ! lanes ( transatlantic travel & become a s]i\s m5ace to navigation 7,fig4 #cah74 ,illu/ration3 ,,fig4 #cai4--;,diagram %[+ "o way 9 :i* nor!rn iceb]gs may be born f ! glaci] tongue 7aft] ,russell74 ,nor!rn iceb]gs ( l>ge dim5sions are born ei!r by ! lift+ ( a sep>at$ portion ( ! ext5d$ glaci] toe ly+ ^u ! bottom ( ! fjord1 or else !y sep>ate bodily f ! cliff itself1 app>5tly :]e x rea*es wat] suffici5tly deep to float x4 ,9 ei!r case ! buoyancy ( ! sea wat] plays a l>ge rle 9 its sep>ation4 ,if d]iv$ f ! subm]g$ glaci] toe 7,fig4 #cai71 a l\d noise is he>d be=e any *ange is visible1 & an in/ant lat] ! great mass ( ice rises out ( ! wat] "s di/ance away f ! cliff1 lift+ z x does s a great volume ( wat] :i* p\rs (f on all sides 9 ?und]+ cascades & exposes at la/ a b]g ( ! deepe/ sapphire blue4 ,! commotion produc$ 9 ! fjord is prodigi\s1 & a vessel 9 close proximity is plac$ 9 jeop>dy4 ,ev5 l>g] b]gs are sometimes se5 to sep>ate f ! ice cliff1 9 ?is case an in/ant be=e or simultane\sly1 ) a l\d report1 b su* b]gs float away ) comp>atively little commotion 9 ! wat]4 ,illu/ration3 ,,fig4 #cbj4--;,a nor!rn iceb]g surr\nd$ by sea ice4 ,! iceb]gs ( ! s\? pol> region are usually built ^u a f> gr&] scale ?an ^? ( ! ,arctic regions1 & are1 fur!r1 bo? di/9ctly tabul> 9 =m & b\nd$ by rectangul> outl9es 7,fig4 #cba74 ,:]eas ! l>ge b]gs ( ,gre5l&ic orig9 are ( ice & blue 9 color1 ! tabul> b]gs ( ,ant>ctica might bett] be describ$ z sn[b]gs1 s9ce !y are ( a bl9d+ :it5ess & _! visible portions are ei!r compact$ sn[ or alt]nat+ ?ick lay]s ( compact sn[ & ?9 ribbons ( blue ice1 ! latt] ?ick] & m abundant t[>d ! base4 ,all su* b]gs h be5 d]iv$ f ! %elf ice & n f ! inl& ice itself4 ,blue iceb]gs :i* h be5 d]iv$ f ! inl& ice h be5 describ$ f ! "o ,ant>ctic l& t has be5 explor$ 9 :i* t ice desc5ds directly to ! sea4 ,illu/ration3 ,,fig4 #cba4--,tabul> ,ant>ctic iceb]g sep>at+ f ! %elf ice 7aft] ,%ackleton74 ,9 bo? ! nor!rn & s\!rn hemisph]es ^? b]gs :i* h float$ into l[] latitudes h suff]$ pr(\nd trans=mations4 ,_! expos$ surfaces h be5 melt$ 9 ! sun1 wa%$ by ! ra91 & batt]$ by ! waves1 s t !y lose _! relatively simple =ms b acquire r\nd$ surfaces 9 place ( ! e>ly angul> ones 7,fig4 #cah1 p4 #bia74 ,sir ,john ,murray1 :o _h su* ext5d$ opportunities ( /udy+ ! s\!rn iceb]gs f ! deck ( ! ,*all5g]1 has ?us describ$ _! beauties3 8,waves da%1 aga9/ ! v]tical faces ( ! float+ ice isl& z aga9/ a rocky %ore1 s t at ! sea level !y are fir/ cut into l$ges & gullies1 & !n into caves & cav]ns ( ! mo/ heav5ly blue1 f out ( :i* !re comes ! res\nd+ ro> ( ! ocean1 & into :i* ! sn[-:ite & o!r petrels may be se5 to w+ _! way ?r\gh gu>ds ( soldi]-l p5gu9s /ation$ at ! entrances4 ,z ^! ice isl&s are sl[ly drift$ by w9d & curr5t to ! nor?1 !y tilt1 turn & sometimes capsize1 & !n subm]g$ prongs & spits are ?r[n high into ! air1 produc+ irregul> p9nacl$ b]gs high]1 possibly1 ?an ! orig9al table-%ap$ mass40 ,,read+ ,,ref]5ces ,,= ,,*apt]s ,,xx ,,& ,,xxi ,g5]al3-- ,i4 ,c4 ,,russell4 ,glaci]s ( ,nor? ,am]ica4 ,g9n1 ,bo/on1 #ahig1 pp4 #baj1 pls4 #bb4 ,,*amb]l9 & ,,salisbury4 ,geology1 vol4 #a1 pp4 #bcb-cjh4 ,h4 ,,hess4 ,die ,glets*]1 ,brauns*weig1 #aijd1 pp4 #dbf 7illu/rat$74 ,,william ,h4 ,,hobbs4 ,*>act]i/ics ( ,exi/+ ,glaci]s4 ,macmillan1 #aiaa1 pp4 #cja1 pls4 #cd4 ,special di/ricts ( m\nta9 glaci]s3-- ,,james ,d4 ,,=bes4 ,travels ,?r\gh ! ,alps ( ,savoy & o!r ,p>ts ( ! ,p5n9e ,*a9 ) ,obs]vations on ! ,ph5om5a ( ,glaci]s4 ,ed9burgh1 #ahde1 pp4 #def1 pls4 #i1 maps #b4 ,a4 ,,p5ck1 ,e4 ,,br,,ckn]1 et ,l4 ,,du ,,pasqui]4 ,le sy/me glaci>e des alpes1 etc41 ,bull4 ,soc4 ,sc4 ,nat4 ,neu*tel1 vol4 #bb1 #ahid1 pp4 #hf4 ,e4 ,,ri*t]4 ,die ,glets*] d] ,o/alp54 ,/uttg>t1 #ahhh1 pp4 #cjf1 #g maps4 ,,james ,d4 ,,=bes4 ,norway & ,its ,glaci]s1 etc4 ,ed9burgh1 #ahec1 pp4 #cdi1 pls4 #aj1 map4 ,i4 ,c4 ,,russell4 ,exi/+ ,glaci]s ( ! ,unit$ ,/ates1 #e? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #cjg-cee1 pls4 #cb-ee2 ,glaci]s ( ,mt4 ,rani]1 #ah? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahih1 pp4 #cdi-dbc1 pls4 #fe-hb4 ,w4 ,h4 ,,%]z]4 ,glaci]s ( ! ,canadian ,rockies & ,selkirks1 ,smi?4 ,cont4 to ,kn[l4 ,no4 #afib1 ,wa%+ton1 #aijg1 pp4 #ace1 pls4 #db4 ,h4 ,f4 ,,reid4 ,/udies ( ,muir ,glaci]1 ,alaska1 ,nat4 ,geogr4 ,mag41 vol4 #d1 #ahib1 pp4 #ai-hd1 pls4 #a-af4 ,i4 ,c4 ,,russell4 ,malasp9a ,glaci]1 ,j\r4 ,geol41 vol4 #a1 #ahic1 pp4 #bai-bde4 ,g4 ,k4 ,,gilb]t4 ,h>riman ,alaska ,exp$ition1 vol4 #c1 ,glaci]s1 #aijd1 pp4 #bca1 pls4 #cg4 ,w4 ,m4 ,,conway4 ,climb+ & ,exploration 9 ! ,k>akoram ,himalayas1 ,maps & ,sci5tific ,reports1 #ahid1 map %eets ,i-,,ii4 ,,fanny ,,bullock ,,workman & ,,william ,,hunt] ,,workman4 ,! ,hisp> ,glaci]1 ,geogr4 ,j\r41 vol4 #ce1 #aiaj1 pp4 #aje-acb1 #g pls4 & map4 ,! cycle ( glaciation3-- ,,william ,h4 ,,hobbs4 ,! ,cycle ( ,m\nta9 ,glaciation1 ,geogr4 ,j\r41 vol4 #cf1 #aiaj1 pp4 #adf-afc1 #bfh-bhd4 ,upp] & l[] cl\d zones ( ! atmosph]e3-- ,r4 ,,assmann1 ,a4 ,,b]son1 & ,h4 ,,gross4 ,wiss5s*aftli*e ,luftfahrt5 ausgefhrt vom deuts*5 ,v]e9 zur ,frd]ung d] ,lufts*iffahrt 9 ,b]l91 #ahii-aijj1 #c vols4 ,e4 ,,gold & ,w4 ,a4 ,,h>wood4 ,! ,pres5t ,/ate ( our ,k ( ! ,upp] ,atmosph]e z ,obta9$ by ! ,use ( ,kites1 ,balloons1 & ,pilot-balloons1 ,rept4 ,brit4 ,assoc4 ,adv4 ,sci41 #aiji1 pp4 #a-ee4 ,w4 ,h4 ,,moore4 ,descriptive ,meteorology1 ,appleton1 ,new ,york1 #aiaj1 pp4 #ie-acf4 ,,william ,h4 ,,hobbs4 ,! ,plei/oc5e ,glaciation ( ,nor? ,am]ica ,view$ 9 ! ,light ( our ,k ( ,exi/+ ,cont95tal ,glaci]s1 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #db1 #aiaa1 pp4 #fdg-fej4 ,! cont95tal glaci] ( ,gre5l&3-- ,f4 ,,nans54 ,! ,fir/ ,cross+ ( ,gre5l&1 #b vols1 ,longmans1 ,london1 #ahij 7! sci5tific results are conta9$ 9 an app5dix to volume #b1 pp4 #ddc-dig74 ,r4 ,e4 ,,pe>y4 ,a ,reconnaissance ( ! ,gre5l& ,inl& ,ice1 ,j\r4 ,am4 ,geogr4 ,soc41 vol4 #ai1 #ahhg1 pp4 #bfa-bhi2 ,j\rneys 9 ,nor? ,gre5l&1 ,geogr4 ,j\r41 vol4 #aa1 #ahih1 pp4 #bac-bdj4 ,t4 ,c4 ,,*amb]l94 ,glaci] ,/udies 9 ,gre5l&1 ,j\r4 ,geol41 vol4 #b1 #ahid1 pp4 #fdi-ffh1 #gfh-ghh1 vol4 #c1 pp4 #fa-fi1 #aih-bah1 #dfi-dhj1 #efe-ehb1 #ffh-fha1 #hcc-hdc1 vol4 #d1 pp4 #ehb-eib1 #gfi-haj1 vol4 #e1 pp4 #bbi-bde2 ,rec5t glacial /udies 9 ,gre5l& 7,presid5tial address71 ,bull4 ,geol4 ,soc4 ,am41 vol4 #f1 #ahie1 pp4 #aii-bbj1 pls4 #c-aj4 ,r4 ,s4 ,,t>r4 ,! ,m>g9 ( ! ,cornell ,glaci]1 ,am4 ,geol41 vol4 #bj1 #ahig1 pp4 #aci-aef1 pls4 #f-ab4 ,r4 ,d4 ,,salisbury4 ,! ,gre5l& ,exp$ition ( #ahie1 ,j\r4 ,geol41 vol4 #c1 #ahie1 pp4 #hge-ijb4 ,e4 ,v4 ,,drygalski4 ,grnl& ,exp$ition d] ,gesells*aft fr ,erdkunde zu ,b]l9 #ahia-ahic1 ,b]l91 #ahig1 #b vols41 pp4 #eea & #ega1 pls4 #ec1 maps #aj4 ,,william ,h4 ,,hobbs4 ,*>act]i/ics ( ! ,inl& ,ice ( ! ,arctic ,regions1 ,proc4 ,am4 ,phil4 ,soc41 vol4 #di1 #aiaj1 pp4 #eg-abi1 pls4 #bf-cj4 ,! ,ant>ctic cont95tal glaci]3-- ,r4 ,f4 ,,scott4 ,! ,voyage ( ! ,discov]y4 ,london1 #b vols41 #aije4 ,e4 ,h4 ,,%ackleton4 ,! ,he>t ( ! ,ant>ctic4 ,london1 #b vols41 #aiaj4 ,e4 ,,von ,,drygalski4 ,zum ,kont95t des eisig5 ,sd5s1 ,deuts*e ,sdpol>-,exp$ition1 ,fahrt5 und ,=s*ung5 des 8,gauss01 #aija-aijc1 ,b]l91 #aijd1 pp4 #ffh1 pls4 #ba4 ,,otto ,,nord5ski,,ld & ,j4 ,s4 ,,&]sson4 ,ant>ctica or ,two ,ye>s ,among/ ! ,ice ( ! ,s\? ,pole4 ,london1 #aije1 pp4 #fjh1 illu/rat$4 ,e4 ,,philippi4 ,ueb] die fnf ,l&eis-,exp$ition51 etc41 ,zeit4 f4 ,glets*]k41 vol4 #b1 #aijg1 pp4 #a-ba4 ,n\ri%m5t ( cont95tal glaci]s3-- ,,william ,h4 ,,hobbs4 ,*>act]i/ics ( ! ,inl& ,ice ( ! ,arctic ,regions1 ,proc4 ,am4 ,phil4 ,soc41 vol4 #di1 #aiaj1 pp4 #if-aaj2 ,! ,ice ,masses on & ab\t ! ,ant>ctic ,cont95t1 ,zeit4 f4 ,glets*]k41 vol4 #e1 #aiaj1 pp4 #ajg-abj2 ,*>act]i/ics ( ,exi/+ ,glaci]s4 ,new ,york1 #aiaa1 pp4 #adc-afa1 #bfa-bhi4 ,plei/oc5e ,glaciation ( ,nor? ,am]ica ,view$ 9 ! ,light ( our ,k ( ,exi/+ ,cont95tal ,glaci]s1 ,bull4 ,am4 ,geogr4 ,soc41 vol4 #dc1 #aiaa1 pp4 #fda-fei4 ,field & pack ice3-- ,,emma ,,de ,,long4 ,! ,voyage ( ! ,jeannette1 ! %ip & ice j\rnals ( ,george ,w4 de ,long1 etc4 ,b]l91 #ahhd1 #b vols41 *>t 9 back ( vol4 #a4 ,,rob]t ,e4 ,,pe>y4 ,! ,discov]y ( ! ,nor? ,pole 7= fur!r ref]5ces on bo? sea & pack ice & ,ant>ctic %elf ice1 consult ,hobbs's ,*>act]i/ics ( ,exi/+ ,glaci]s1 pp4 #baj-bac1 #bdb-bdd74 ,iceb]gs3-- ,,wyville ,,?omson4 ,*all5g] ,report1 ,n>rative1 vol4 #a1 #ahfe1 ,pt4 i1 pp4 #dca-dcb1 pls4 ,b-,d4 ,i4 ,c4 ,,russell4 ,an ,exp$ition to ,mt4 ,/4 ,elias1 ,nat4 ,geogr4 ,mag41 vol4 #c1 #ahia1 pp4 #aja-ajb1 fig4 #a4 ,h4 ,f4 ,,reid4 ,/udies ( ,muir ,glaci]1 ,alaska1 ibid41 vol4 #d1 #ahib1 pp4 #dg-dh4 ,e4 ,,von ,,drygalski4 ,grnl&-,exp$ition1 etc41 vol4 #a1 pp4 #cfg-djd4 ,m4 ,c4 ,,engell4 ,ueb] die ,ent/ehung d] ,eisb]ge1 ,zeit4 f4 ,glets*]k41 vol4 #e1 #aiaj1 pp4 #aab-acb4 ,,*apt] ,,xxii ,,! ,,cont95tal ,,glaci]s ,,( ,,! 8,,ice ,,age0 ,e>li] cycles ( glaciation4--,our /udy ( ! rocks compos+ ! out]mo/ %ell ( ! li?osph]e tells u t 9 at lea/ ?ree widely sep>at$ p]iods ( its hi/ory ! e>? has pass$ ?r\gh cycles ( glaciation dur+ :i* consid]able portions ( its surface h be5 subm]g$ b5ea? cont95tal glaci]s4 ,! late/ ( ^! occurr$ 9 ! ye/]day ( geology & has (t5 be5 ref]r$ to z ! 8ice age01 because until q rec5tly x 0 suppos$ to be ! only "o ( :i* a record 0 pres]v$4 ,illu/ration3 ,,fig4 #cbb4--,map ( ! globe %[+ ! areas :i* 7 cov]$ by ! cont95tal glaci]s ( ! s-call$ 8ice-age0 ( ! ,plei/oc5e p]iod4 ,! arr[s %[ ! directions ( ! c5trifugal air curr5ts 9 ! fix$ anticyclones above ! glaci]s4 ,illu/ration3 ,,fig4 #cbc4--;,glaciat$ granite b[ld] :i* has wea!r$ out ( a mora9e ( ,p]mo-,c>bonif]\s age ^u :i* x re/s4 ,s\? ,au/ralia 7aft] ,h[*974 ,?is late/ ice age repres5ts f\r complete cycles ( glaciation1 = x is believ$ t ! cont95tal ice develop$ & !n completely disappe>$ dur+ a p]iod ( mild climate be=e ! next glaci] _h =m$ 9 its place1 & t ?is alt]nation ( climates 0 no less ?an ?ree times repeat$1 mak+ f\r cycles 9 all4 ,at ne>ly or q ! same "t ice masses develop$ 9 nor!rn ,nor? ,am]ica & 9 nor!rn ,europe1 ! embossm5ts ( ! ice domes be+ locat$ 9 ,canada & 9 ,sc&9avia respectively 7,fig4 #cbb74 ,!re appe>s to h be5 at ?is "t no ext5sive glaciation ( ! s\!rn hemisph]e1 ?\gh 9 ! next e>li] ( ! kn[n great p]iods ( glaciation--! s-call$ ,p]mo-,c>bonif]\s--x 0 ! s\!rn hemisph]e1 & n ! nor!rn1 t 0 affect$ 7,fig4 #cbc & ,fig4 #cjd1 p4 #bgf74 ,f ! /ill e>li] glacial p]iod our data are naturally mu* m meag]1 b x seems probable t x 0 *>act]iz$ by glaciat$ areas )9 bo? ! nor!rn & ! s\!rn hemisph]es4 ,illu/ration3 ,,fig4 #cbd4--,map to %[ ! glaciat$ & nonglaciat$ regions ( ,nor? ,am]ica 7aft] ,salisbury & ,atwood74 ,contra/ ( ! glaciat$ & nonglaciat$ regions4--,s9ce we h n[ /udi$ 9 brief outl9e ! *>act]i/ics ( ! exi/+ cont95tal glaci]s1 we are 9 a position to review ! evid5ces ( =m] glaci]s1 ! records ( :i* exi/ 9 _! c>v+s1 _! grav+s1 & _! deposits4 ,illu/ration3 ,,fig4 #cbe4--,map ( ! glaciat$ & nonglaciat$ areas ( nor!rn ,europe4 ,! /rongly m>k$ mora9al belts respectively s\? & nor? ( ! ,baltic depression repres5t halt+ places 9 ! retreat ( ! late/ cont95tal glaci] 7compil$ f maps by ,p5ck & ,lev]ett74 ,an obs]vant p]son famili> ) ! aspects ( ,nature 9 bo? ! nor!rn & s\!rn portions ( ! c5tral & ea/]n ,unit$ ,/ates mu/ h notic$ t ! g5]al c\rses ( ! ,ohio & ,miss\ri riv]s def9e a some:at m>k$ common bord] ( areas :i* 9 mo/ respects are %>ply contra/$ 7,fig4 #cbd74 ,h>dly less /rik+ is ! contra/ betwe5 ! glaciat$ & ! nonglaciat$ regions ^u ! cont95t ( ,europe 7,fig4 #cbe74 ,x is ! nor!rn ( ! two areas :i* 9 ea* case reveals ! *>act]i/ic evid5ces ( glaciation1 :ile !re is entire abs5ce ( su* m>ks to ! s\?w>d ( ! common bord]4 ,)9 ! ,am]ican glaciat$ region !re is1 h[ev]1 an area surr\nd$ l an isl&1 & )9 ?is di/rict 7,fig4 #cbd7 none ( ! m>ks *>act]i/ic ( glaciation are to be f\nd4 ,?is area is usually ref]r$ to z ! 8driftless area01 & occupies portions ( ! /ates ( ,wiscons91 ,ill9ois1 ,m9nesota1 & ,i[a4 ,ev5 bett] ?an ! area to ! s\?w>d ( ! ,ohio & ,miss\ri riv]s1 x p]mits ( a comp>ison ( ! nonglaciat$ ) ! drift-cov]$ region4 ,illu/ration3 ,,fig4 #cbf4--8,/& ,rock0 ne> ! 8,dells0 ( ! ,wiscons9 riv]1 an un/able erosion remnant *>act]i/ic ( ! driftless area ( ,nor? ,am]ica 7aft] ,salisbury & ,atwood74 ,! 8driftless area40--,)9 ?is di/rict1 !n1 we h pres]v$ = our /udy a l&scape :i* rema9s l>gely z x 0 be=e ! sev]al ice invasions _h s pr(\ndly trans=m$ ! g5]al surface ( ! surr\nd+ c\ntry4 ,speak+ broadly1 we may say t x repres5ts an uplift$ & 9 "p dissect$ pla91 :i* to ! s\? & ea/ p>ticul>ly reveals ! "* ( ne>ly mature riv] erosion 7,fig4 #agg1 p4 #agj74 ,! rock surface is "h ev]y:]e mantl$ by decompos$ & dis9tegrat$ rock residues ( local orig94 ,! soluble con/itu5ts ( ! rock1 su* z ! c>bonates1 h be5 remov$ by ! process ( lea*+1 s t ! clays no long] eff]vesce :5 treat$ ) dilute m9]al acid4 ,:]ev] favor$ by jo9ts & by an alt]nation ( h>d] & s(t] rock lay]s1 picturesque un/able erosion remnants or 8*imneys0 may /& out 9 relief 7,fig4 #cbf74 ,fur!rmore1 ! driftless area is ?r\gh\t p]fectly dra9$--x is )\t lakes or swamps--s9ce all valleys are *>act]iz$ ?r\gh\t by =w>d grades4 ,! side valleys ent] ! ma9 valleys z d ! bran*es a tree trunk2 9 o!r words1 ! dra9age is describ$ z arboresc5t4 ,9 s f> z any portions ( a plane surface n[ rema9 9 ! l&scape1 !y are f\nd at ! highe/ levels 7plate #af ,a74 ,! topography is ?us ! result ( a p>tial removal by erosion ( an upl& & may be describ$ z incis$ topography4 ,n[h]e )9 ! area are !re f\nd rock masses =eign to ! region1 b all mantle rock is ! wea!r$ product ( ! und]ly+ l$ges4 ,,plate #af4 ,illu/ration3 ,a4 ,incis$ topography )9 ! 8driftless area0 7,u4 ,s4 ,geol4 ,survey74 ,illu/ration3 ,b4 ,built-up topography )9 glaciat$ region 7,u4 ,s4 ,geol4 ,survey74 ,*>act]i/ics ( ! glaciat$ regions4--,! topography ( ! driftless area has be5 describ$ z incis$1 because due to ! p>tial de/ruction ( an uplift$ pla92 & ?is surface is1 moreov]1 p]fectly dra9$4 ,! *>act]i/ic topography ( ! 8drift0 areas is by contra/ built up2 t is to say1 ! features ( ! region in/ead ( be+ c>v$ out ( a pla9 are ! result ( mold+ by ! process ( deposition 7plate #af ,b74 ,9 s f> z a plane is recognizable1 x is to be f\nd n at ! highe/1 b at ! l[e/ level--a surface repres5t$ l>gely by swamps & lakes--& above ?is pla9 rise ! *>act]i/ic r\nd$ hills ( v>i\s types :i* h be5 built up ?r\gh deposition4 ,! process by :i* ?is has be5 accompli%$ is "o easy to compreh5d4 ,z x invad$ ! region1 ! glaci] plan$ away b5ea? its m>g9al zone all wea!r$ mantle rock & deposit$ ! plan+s )9 ! holl[s ( ! surface 7,fig4 #cbg74 ,! effect has be5 to flatt5 out ! prexi/+ irregul>ities ( ! surface1 & to yield at fir/ a g5tly undulat+ pla9 ^u :i* are _m undra9$ areas & a haphaz>d sy/em ( dra9age 7,fig4 #cbh74 ,all un/able erosion remnants1 su* z n[ are to be f\nd )9 ! driftless area1 7 ! fir/ to be toppl$ ov] by ! invad+ glaci]1 & 9 _! place !re is left at be/ only r\nd$ & poli%$ 8%\ld]s0 ( h>d & unwea!r$ rock--! well-kn[n ro*es m\tonnes4 ,illu/ration3 ,,fig4 #cbg4--;,diagram %[+ ! mann] 9 :i* a cont95tal glaci] oblit]ates exi/+ valleys 7aft] ,t>r74 ,! glaci] grav+s4--,! tools ) :i* ! glaci] works are nev] q ev5ly edg$1 & in/ead ( an 9 all respects p]fect poli% ^u ! rock pavem5t1 !re are left furr[+s1 g\g+s1 & scrat*es4 ,( :atev] sort1 ^! scor+s indicate ! l9es ( ice movem5t & are ?us indubitable records grav5 ^u ! rock floor4 ,:5 mapp$ ov] wide areas1 a mo/ int]e/+ picture is pres5t$ to our view1 & "o :i* supplem5ts 9 an important way ! /udies ( exi/+ cont95tal glaci]s 7,fig4 #ccd1 p4 #cjh1 & ,fig4 #ccf1 p4 #cab74 ,illu/ration3 ,,fig4 #cbh4--,lake & m>% di/rict 9 nor!rn ,wiscons91 ! effect ( glacial deposition 9 =m] valleys 7aft] ,fairbanks74 ,x has be5 cu/om>y to ?9k ( ! glaci] z ev]y:]e erod+ its b$1 al?\gh ! only w>rant = assum+ degradation by fl[ ( ! ice is re/rict$ to ! m>g9al zone1 s9ce "h only is !re an appreciable surface grade likely to induce fl[4 ,bo? ^u ! advance & aga9 dur+ ! retreat ( a glaci]1 all p>ts ( ! area ov]ridd5 mu/ be subject$ to ?is action4 ,h]et(ore pictur$ 9 ! imag9ation z enl>g$ models ( ,alp9e glaci]s1 ! va/ ice mantles 7 conceiv$ to h spread out ov] ! c\ntry z ! result ( a k9d ( visc\s fl[ l t ( molasses p\r$ ^u a flat surface 9 cold wea!r4 ,! maximum ?ickness ( ! late/ ,am]ican glaci] ( ! ice age has be5 assum$ to h be5 p]haps #aj1jjj feet ne> ! summit ( its dome 9 c5tral ,labrador4 ,f ?is po9t x 0 assum$ t ! ice travel$ s\?w>d up ! nor!rn slope ( ! ,laur5tian divide 9 ,canada1 & !nce to ! ,ohio riv]1 a di/ance ( ov] #acjj miles4 ,if su* a mantle ( ice be repres5t$ 9 its natural proportions 9 v]tical section1 to cov] ! di/ance f c5t] to m>g9 we may use a l9e six in*es 9 l5g?1 & only #a_/ajj ( an in* ?ick4 ,^u a r$uc$ scale ^! proportions are giv5 9 ,fig4 #cbi4 ,obvi\sly ! =ce ( gravity act+ )9 a visc\s mass ( su* proportions w\ld be incompet5t to effect a transf] ( mat]ial f ! c5t] to ! p]iph]y1 ev5 ?\gh ! ?ickness %\ld be d\bl$ or trebl$4 ,yet until ! fix$ glacial anticyclone above ! glaci] _h be5 prov5 & its effici5cy z a broom recogniz$1 no o!r hypo!sis ?an t ( visc\s fl[ _h be5 (f]$ 9 explanation4 ,! inh]it$ conception ( a univ]sal pluck+ & abrasion on ! b$ ( ! glaci] is ?us made unt5able & c be accept$ = ! m>g9al portion only4 ,illu/ration3 ,,fig4 #cbi4--;,cross section 9 approximate natural proportions ( ! late/ ,nor? ,am]ican cont95tal glaci] ( ,plei/oc5e age f its c5t] to its m>g94 ,n only d ! rock scor+s %[ ! l9es ( ice movem5t1 b ! directions z well may (t5 be read ^u ! rock4 ,:]ev] !re are pron\nc$ irregul>ities ( surface /ill exi/+ on ! pavem5t1 ^! are g5]ally f\nd to h gradual slopes ^u ! side f :i* ! ice came1 & relatively /eep falls ^u ! lee or 8pluck0 side4 ,if1 h[ev]1 we consid] ! irregul>ities ( small] size1 ! unsymmetrical slopes ( ^! protrud+ portions ( ! floor are f\nd to be rev]s$--x is ! /eep slope :i* faces ! oncom+ ice & ! flatt] slope :i* is ^u ! lee side4 ,su* m9or projections ^u ! floor usually h _! orig9 9 "s h>d] nodule :i* deflects ! abrad+ tools & causes !m to pass1 "s on ! "o side & "s ^u ! o!r4 ,by ?is process a /aple-%ap$ groove comes to surr\nd ! nodule1 leav+ an unsymmetrical elevat$ ridge )91 :i* is /eep ^u ! /oss side & slopes g5tly away to leew>d4 ,illu/ration3 ,,fig4 #ccj4--,lime/one surface at ,sibley1 ,mi*igan4 ,y\ng] records ov] old]--! glaci] palimpse/4--,_m important hi/orical facts h be5 recov]$ f ! l>gely effac$ writ+ ^u anci5t palimpse/s1 or p>*m5ts ^u :i* an e>li] record has be5 int5tionally eras$ to make room = ano!r4 ,9 ! grav+s ^u ! glaci] pavem5t1 e>li] records h be5 likewise 9 l>ge "p effac$ by lat]1 ?\gh 9 favorable localities ! two may be read toge!r4 ,?us1 z an example1 at ! great lime/one qu>ries ( ,sibley1 9 s\!a/]n ,mi*igan1 ! glaciat$ rock surface :]ev] /ripp$ ( its drift cov] is a smoo?ly poli%$ & relatively level floor ) /ri :i* are direct$ we/-nor?we/4 ,b5ea? ?is g5]al surface !re are1 h[ev]1 a numb] ( elliptical depressions :i* h _! long] axes direct$ s\?-s\?we/1 "o be+ f tw5ty-five to ?irty feet long & "s t5 feet 9 dep? 7,fig4 #ccj74 ,^! boat-%ap$ depressions are cle>ly ! remnants ( an e>li] m undulat+ surface :i* ! late/ glaci] has 9 l>ge "p plan$ away1 s9ce ! bottoms ( ! depressions are no less p]fectly glaciat$ b h _! /ri direct$ 9 g5]al ne> ! long] axis ( ! tr\ghs4 ,palimpse/-l !re are "h also ! records ( m ?an "o grav+4 ,illu/ration3 ,,fig4 #cca4--,map to %[ ! outcropp+s ( peculi> rock types 9 ! region ( ! ,great ,lakes1 & "s ( ! localities :]e 8float copp]0 has be5 collect$ 7float copp] localities aft] ,salisbury74 ,! disp]sion ( ! drift4--,long be=e ! 8ice age0 _h be5 conceiv$ 9 ! m9ds ( ,agassiz & 8 contempor>ies1 x _h be5 rem>k$ t scatt]$ ov] ! ,nor? ,g]man pla9 7 r\nd$ fragm5ts ( rock :i* c\ld n possibly h be5 d]iv$ f _! own neighborhood b :i* c\ld be mat*$ ) ! great masses ( r$ granite 9 ,sw$5 well kn[n z ! 8,sw$i% granite40 ,buckl&1 an ,engli% geologi/1 _h 9 #ahae acc\nt$ = su* 8erratic0 blocks ( 8 own c\ntry1 "h ( ,scot* granite1 by call+ 9 ! deluge ( ,noah2 b 9 ! late ?irties ( ! n9ete5? c5tury1 ,sir ,*>les ,lyell1 ) ! results ( ,engli% ,arctic explor]s 9 m9d1 claim$ t su* travel$ blocks _h be5 transport$ by iceb]gs emanat+ f ! pol> regions4 ,a relic ( ,buckl&'s e>li] view we h 9 ! ^w 8diluvium0 /ill occasionally us$ 9 ,g]many = glaci] transport$ mat]ials2 :ile ! t]m 8drift0 /ill rema9s 9 common use to recall ,lyell's iceb]g hypo!sis1 ev5 ?\gh ! orig9al mean+ ( ! t]m has be5 ab&on$4 ,drift is n[ a g5]ic t]m & ref]s to all deposits directly or indirectly ref]able to ! cont95tal glaci]s4 ,9 g5]al ! place ( d]ivation ( ! glacial drift may be said to be "s po9t m di/ant f & )9 ! =m] ice m>g9 at ! "t :5 x 0 deposit$2 9 o!r words1 ! disp]sion ( ! drift 0 c5trifugal ) ref]5ce to ! glaci]4 ,illu/ration3 ,,fig4 #ccb4--,map ( ! 8b[ld] tra90 f ,iron ,hill1 ,r4 ,i4 7bas$ ^u ,%al]'s map1 b ) ! directions ( glacial /ri add$74 ,:]ev] rocks ( unusual & !re=e easily recognizable "* c be %[n to occur 9 place & ) b limit$ areas1 ! disp]sion ( su* mat]ial is easy to trace4 ,! areas ( r$ ,sw$i% & ,scot* granite h be5 us$ to foll[ out 9 a broad way ! disp]sion ( drift ov] nor!rn ,europe4 ,)9 ! region ( ! ,great ,lakes ( ,nor? ,am]ica are areas ( limit$ size :i* are occupi$ by well m>k$ rock types1 s t ! j\rney+s ( _! fragm5ts ) ! cont95tal glaci] c be mapp$ ) "s c>e4 ,^u ! nor!rn %ore ( ,georgian ,bay occurs ! beautiful jasp] conglom]ate1 ^: bright r$ pebbles 9 _! :ite qu>tz field attract su* g5]al notice4 ,at ,i%pem+ 9 ! nor!rn p59sula ( ,mi*igan is f\nd ! equally beautiful jaspilite compos$ ( puck]$ alt]nat+ lay]s ( black hematite & r$ jasp]4 ,on ,kewe5aw ,p59sula1 :i* protrudes into ,lake ,sup]ior f its s\!rn %ore1 is f\nd t rem>kable occurr5ce ( native copp] )9 a s]ies ( igne\s rocks ( v>i$ types & colors4 ,fragm5ts ( ?is copp]1 "s weigh+ sev]al hundr$s ( p\nds ea* & mask$ 9 a coat ( gre5 mala*ite1 h "u ! "n ( 8drift0 or 8float0 copp] be5 collect$ at _m localities )9 a broad 8fan0 ( disp]sal ext5d+ almo/ to ! v limits ( glaciation 7,fig4 #cca74 ,"s miles to ! nor? ( ,provid5ce 9 ,rhode ,isl& !re is a hill kn[n z ,iron ,hill compos$ 9 l>ge "p ( black magnetite rock1 ! s-call$ ,cumb]l&ite4 ,f ?is hill z an apex !re has be5 disp]s$ a great quantity ( ! rock di/ribut$ z a well m>k$ 8b[ld] tra90 )9 :i* ! size & ! frequ5cy ( ! disp]s$ b[ld]s is 9 inv]se ratio to ! di/ance f ! p>5t l$ge 7,fig4 #ccb74 ,simil> ?\gh less p]fect tra9s ( b[ld]s are f\nd on ! lee side ( mo/ project+ masses ( resi/ant rocks )9 ! area ( ! drift4 ,l>ge b[ld]s :5 left ^u a l$ge ( notably diff]5t appe>ance easily attract att5tion1 & h be5 describ$ z 8p]*$ b[ld]s40 ,re/+ z !y sometimes d ^u a relatively small area1 !y may be nicely balanc$ & ?us easily giv5 a p5dul> or rock+ motion4 ,su* 8rock+ /ones0 are common en\gh1 especially among ! ,new ,engl& hills 7plate #ag ,b74 ,_m su* b[ld]s h made some:at rem>kable p]egr9ations ) _m int]ruptions1 hav+ be5 c>ri$ fir/ 9 "o direction by an e>li] glaci] to be lat] transport$ 9 :olly diff]5t directions at ! "t ( new ice invasions4 ,,plate #ag4 ,illu/ration3 ,a4 ,sol$ glacial b[ld]s :i* %[ diff]5tly direct$ /ri ^u ! same facet4 ,illu/ration3 ,b4 ,p]*$ b[ld] ^u a /riat$ l$ge ( diff]5t rock type1 ,bronx ,p>k1 ,new ,york 7aft] ,lung/$t74 ,illu/ration3 ,c4 ,*>act]i/ic knob & bas9 surface ( a mora9e4 ,! diamonds ( ! drift4--,( consid]able popul>1 ev5 if n economic1 int]e/ are ! diamonds :i* h be5 s[n 9 ! drift aft] long & int]rupt$ j\rney+s ) ! ice f "s unkn[n home f> to ! nor?w>d 9 ! wild]ness ( ,canada4 ,! fir/ /one to be discov]$ 0 tak5 by workm5 f a well op5+ ne> ! little t[n ( ,eagle 9 ,wiscons9 9 ! ye> #ahgf4 ,its nature n be+ kn[n1 x rema9$ :]e x 0 f\nd z a curiosity only1 & x 0 n until #ahhc t x 0 tak5 to ,milwaukee & sold to a jewel] equally ignorant ( its value1 & = ! m]ely nom9al sum ( "o doll>4 ,lat] recogniz$ z a diamond ( ! unusual weight ( sixte5 c>ats1 x 0 sold to ! ,tiffanys & became ! cause ( a long litigation :i* did n end until ! ,supreme ,c\rt ( ,wiscons9 _h decid$ t ! ,milwaukee jewel]1 & n ! f9d]1 0 entitl$ to ! price ( ! /one1 s9ce he _h be5 ignorant ( its value at ! "t ( pur*ase4 ,illu/ration3 ,,fig4 #ccc4--,%apes & approximate natural sizes ( "s ( ! m important diamonds f ! ,great ,lakes region ( ! ,unit$ ,/ates4 ,9 ord] f left to "r ^! figures repres5t ! ,eagle diamond ( sixte5 c>ats1 ! ,saukville diamond ( six & "o half c>ats1 ! ,mil=d diamond ( six c>ats1 ! ,oregon diamond ( f\r c>ats1 & ! ,burl+ton diamond ( a little ov] two c>ats4 ,an ev5 l>g] diamond1 ( tw5ty-"o c>ats weight1 0 f\nd at ,kohlsville1 & small] ones at ,oregon1 ,saukville1 ,burl+ton1 & ,plum ,creek 9 ! /ate ( ,wiscons92 at ,d[agiac 9 ,mi*igan2 at ,mil=d 9 ,ohio1 & 9 ,morgan & ,br[n c\nties 9 ,indiana4 ,! appe>ance ( "s ( ! l>g] /ones 9 _! natural size & %ape may be se5 9 ,fig4 #ccc4 ,:ile ! numb] ( ! diamonds s[n 9 ! drift is und\bt$ly l>ge1 _! disp]sion is su* t x is little likely !y c be pr(itably recov]$4 ,! di/ribution ( ! localities at :i* /ones h ?us f> be5 f\nd is set =? ^u ,fig4 #ccd4 ,obvi\sly ^? t h be5 f\nd are ! ones ( l>g] size1 s9ce ^! only attract att5tion4 ,9 #ahic1 :5 ! f9d+ ( ! ,oregon /one drew att5tion to ^! d5iz5s ( ! drift1 ! writ] prophesi$ t o!r /ones w\ld occasionally be discov]$ "u ess5tially ! same conditions1 & su* discov]ies are c]ta9 to cont9ue 9 ! future4 ,illu/ration3 ,,fig4 #ccd4--;,glacial map ( a portion ( ! ,great ,lakes region1 %[+ ! unglaciat$ area & ! areas ( old] & new] drift4 ,! driftless area1 ! mora9es ( ! lat] ice invasion1 & ! di/ribution ( diamond localities ^u ! latt] are also %[n4 ,) ! aid ( ! directions ( /ri "s attempt has be5 made to indicate ! probable tracks ( m important diamonds1 :i* tracks conv]ge 9 ! direction ( ! ,labrador p59sula4 ,tabulat$ comp>ison ( ! glaciat$ & nonglaciat$ regions4--,x w n[ be pr(itable to sum up 9 p>allel columns ! contra/$ peculi>ities ( ! glaciat$ & ! unglaciat$ regions4 ,,unglaciat$ ,,region ,,glaciat$ ,,region ,,topography ,! topography is de/ructional2 ,! topography is con/ructional2 ! remnants ( a pla9 are f\nd ! remnants ( a pla9 are f\nd at ! highe/ levels or ^u ! at ! l[e/ levels 9 lakes & hill tops2 hills are c>v$ out swamps2 hills are mold$ above a ( a high pla92 un/able erosion pla9 9 *>act]i/ic =ms2 no remnants are *>act]i/ic4 un/able erosion remnants1 b only r\nd$ %\ld]s ( rock4 ,,dra9age ,! area is completely dra9$1 ,! area includes undra9$ & ! dra9age network is areas1--lakes & swamps1--& arboresc5t4 ! dra9age sy/em is haphaz>d4 ,,rock ,,mantle ,! expos$ rock is decompos$ ,no decompos$ or dis9tegrat$ & dis9tegrat$ to a rock is 89 place01 b only consid]able dep?2 x is all ( h>d1 fre% surface2 loose rock local d]ivation & h5ce ( few mat]ial is all =eign & ( _m types--homog5e\s2 ! fragm5ts sizes & types--het]og5e\s2 are angul>2 soils are lea*$ & rock b[ld]s & pebbles are h5ce d n conta9 c>bonates4 facet$ & poli%$ z well z /riat$1 usually 9 sev]al directions ^u ea* facet2 soils are rock fl\r--! gri/ ( ! glacial mill4 ,,rock ,,surface ,rock surface is r\gh & ,rock surface is plan$ or groov$1 irregul>4 & poli%$4 ,%[s glacial /ri4 ,unassort$ & assort$ drift4--,! drift is ( two di/9ct types2 namely1 t deposit$ directly by ! glaci]1 :i* is )\t /ratification1 or unassort$2 & t deposit$ by wat] fl[+ ei!r b5ea? or f ! ice1 & ?is l mo/ fluid deposit$ mat]ial is assort$ or /ratifi$4 ,! unassort$ mat]ial is describ$ z till1 or sometimes z 8b[ld] clay02 ! assort$ is s& or gravel1 sometimes ) small includ$ b[ld]s1 & is describ$ z kame gravel4 ,to recall ! p>ts :i* bo? ! glaci] & ! /reams h play$ 9 its deposition1 all wat]-deposit$ mat]ials 9 connection ) glaci]s are call$ fluvio-glacial4 ,illu/ration3 ,,fig4 #cce4--,section 9 co>se till4 ,note ! range 9 size ( ! mat]ials1 ! lack ( /ratification1 & ! 8sol$0 =m ( ! b[ld]s4 ,till is1 !n1 *>act]iz$ by a notewor?y lack ( homog5eity1 bo? z reg>ds ! size & ! composition ( its con/itu5t p>ts4 ,z _m z tw5ty diff]5t rock types ( v>i$ textures & colors may sometimes be f\nd 9 a s+le exposure ( ?is mat]ial1 & ! entire gamut is run f ! f9e/ rock fl\r ^u ! "o h& to b[ld]s ^: diamet] may be measur$ 9 feet 7,fig4 #cce74 ,9 contra/ ) ^? d]iv$ by ord9>y /ream action1 ! pebbles & b[ld]s ( ! till are facet$ or 8sol$01 & usually %[ /riations ^u _! faces4 ,if a numb] ( pebbles are exam9$1 "s at lea/ are sure to be f\nd ) /riations 9 m ?an "o direction ^u a s+le facet4 ,z a crit]ion = ! discrim9ation ( ! mat]ial ?is may be an important m>k to be made use ( to di/+ui% 9 special cases f rock fragm5ts d]iv$ by brecciation & slick5sid+ & di/ribut$ by ! torr5ts ( arid & semi>id regions4 ,inasmu* z ! capacity ( ice = h&l+ l>ge masses is great] ?an t ( wat]1 assort$ drift is 9 g5]al less co>se1 &1 z its "n implies1 x is also /ratifi$4 ,f ord9>y /ream gravels1 ! kame gravels are di/+ui%$ by ! =m ( _! pebbles1 :i* are g5]ally facet$ & 9 "s cases /riat$4 ,9 proportion1 h[ev]1 z ! mat]ials are mu* work$ ov] by ! wat]1 ! angles betwe5 pebble faces become r\nd$ & ! orig9al %apes consid]ably mask$4 ,features into :i* ! drift is mold$4--,?\gh ! prexi/+ valleys 7 fir/ fill$ 9 by drift mat]ials1 ?us r$uc+ ! acc5t ( ! relief1 a cont9uation ( ! same process result$ 9 ! sup]imposition ( features ( *>act]i/ic %apes ^u ! imp]fectly ev5$ surface ( ! e>li] /ages4 ,^! features belong to sev]al diff]5t types1 accord+ z !y 7 built up outside (1 at & ^u1 or )9 ! glaci] m>g94 ,! extra-m>g9al deposits are describ$ z outwa% pla9s or aprons1 or sometimes z valley tra9s2 ! m>g9al are ei!r mora9es or kames2 :ile )9 ! bord] 7 =m$ ! till pla9 or gr\nd mora9e1 &1 locally also1 ! druml9 & ! esk] or os4 ,^! *>act]i/ic features are ) few exceptions to be f\nd only )9 ! area cov]$ by ! late/ ( ! ice invasions4 ,= ! e>li] ones1 s mu* "t has n[ elaps$ t ! effect ( wea!r+1 wa%1 & /ream erosion has be5 su* t few ( ! features are recognizable4 ,m>g9al & extra-m>g9al features are ext5d$ 9 ! direction ( ! m>g9 or1 9 o!r words1 p]p5dicul> to ! local ice movem5t2 :ile ! intra-m>g9al deposits are z notewor?y = be+ p]p5dicul> to ! m>g91 or 9 correspond5ce ) ! direction ( local ice movem5t4 ,ea* ( ^! features possesses *>act]i/ic m>ks 9 its =m1 its size1 proportions1 surface mold+ & ori5tation1 z well z 9 its con/itu5t mat]ials4 ,x %\ld p]haps be po9t$ out t ! exi/+ cont95tal glaci]s1 be+ 9 high latitudes1 "w ^u rock mat]ials :i* h be5 subject$ to diff]5t wea!r+ processes f ^? *>act]i/ic ( temp]ate latitudes4 ,moreov]1 ! melt+ ( ! ,plei/oc5e glaci]s hav+ tak5 place 9 relatively l[ latitudes1 l>g] quantities ( rock dbris 7 probably releas$ f ! ice dur+ ! "t ( def9ite climatic *anges1 & h5ce heavi] drift accumulations h = bo? ( ^! reasons result$4 ,m>g9al or 8kettle0 mora9es4--,:]ev] = a protract$ p]iod ! m>g9 ( ! glaci] 0 halt$1 consid]able deposits ( drift 7 built up at ! ice m>g94 ,^! accumulations =m1 h[ev]1 n only ab\t ! m>g91 b ^u ! ice surface z well2 9 "p due to mat]ials collect$ f melt+ d[n ( ! surface1 & 9 "p by ! upturn+ ( ice lay]s ne> ! m>g9 7see ante1 p4 #bgg74 ,illu/ration3 ,,fig4 #ccf4--,sket* map ( portions ( ,mi*igan1 ,ohio1 & ,indiana1 %[+ ! fe/oon$ outl9es ( ! mora9es ab\t ! =m] ice lobes1 & ! directions ( ice movem5t z det]m9$ by ! /ri ^u ! rock pavem5t 7aft] ,lev]ett74 ,an important rle is play$ by ! ?aw wat] :i* em]ges at ! ice m>g91 especially )9 ! rentrants or recesses ( ! outl9e4 ,! mat]ials ( mora9es are1 !re=e1 till ) l>ge local deposits ( kame gravel1 & ^! =m 9 a s]ies ( ridges correspond+ to ! tempor>y positions ( ! ice front4 ,_! wid? may range f a few rods to a few miles1 _! height may rea* a hundr$ feet or m1 & !y /ret* across ! c\ntry = di/ances ( hundr$s or ev5 ?\s&s ( miles1 loop$ 9 arcs or scallops :i* are always convex outw>d & :i* meet 9 %>p cusps t 9 a g5]al way po9t t[>d ! embossm5t ( ! =m] glaci] 7,fig4 #ccd1 p4 #cjh1 & ,fig4 #ccf74 ,^! fe/oons ( ! mora9es outl9e ! ice lobes ( ! late/ ice invasion1 :i* 9 ,nor? ,am]ica 7 c5t]$ ov] ! depressions n[ occupi$ by ! ,laur5tian lakes4 ,!re 01 ?us1 a ,lake ,sup]ior lobe1 a ,lake ,mi*igan lobe1 etc4 ,) ! aid ( ^! mora9e maps we may ?us 9 imag9ation picture 9 broad l9es ! frontal cont\rs ( ! e>li] glaci]s4 ,at specially favorable localities :]e ! ice front has cross$ a deep valley at ! edge ( ! ,driftless ,area1 we may1 ev5 9 a r\gh way1 measure ! slope ( ! ice face4 ,?us ne> ,devils ,lake 9 s\!rn ,wiscons9 ! t]m9al mora9e crosses ! =m] valley ( ! ,wiscons9 ,riv]1 & 9 s do+ has dropp$ a di/ance ( ab\t f\r hundr$ feet )9 ! di/ance ( a half mile or !reab\ts 7,fig4 #ccg74 ,! *>act]i/ic surface ( ! m>g9al mora9e is responsible = ! "n 8kettle0 mora9e s g5]ally appli$ to x4 ,! 8kettles0 are r\ghly circul>1 undra9$ bas9s :i* lie among hummocks or knobs1 s t ! surface has (t5 be5 ref]r$ to z 8knob & bas90 topography 7plate #ag ,c74 ,illu/ration3 ,,fig4 #ccg4--,map ( ! vic9ity ( ,devils ,lake1 ,wiscons91 locat$ )9 a rentrant ( ! 8kettle0 mora9e ^u ! m>g9 ( ! ,driftless ,area4 ,! lake lies )9 an e>li] *annel ( ! ,wiscons9 ,riv] :i* has be5 block$ at bo? ends1 fir/ by ! glaci] & lat] by its mora9e4 ,! /ippl$ area ^u ! heights & next ! mora9e repres5ts ! clay deposits ( a =m] lake 7bas$ on map by ,salisbury & ,atwood74 ,illu/ration3 ,,fig4 #cch4--,mora9e ) outwa% apron 9 front1 ! latt] 9 "p erod$ by a riv]4 ,we/]gtl&1 ,sw$5 7aft] ,h4 ,mun!74 ,illu/ration3 ,,fig4 #cci4--;,fosse betwe5 an outwa% pla9 79 ! =egr\nd7 & ! mora9e1 :i* rises to ! left 9 ! middle di/ance4 ,ann ,arbor1 ,mi*igan4 ,kames4--,)9 rentrants or recesses ( ! ice m>g9 ! drift deposits 7 especially heavy1 s t high hills ( hummocky surface h be5 built up1 :i* are describ$ z kames4 ,mo/ ( ! high] drift hills h ?is orig94 ,!y r>ely h any pr9cipal ext5sion along a s+le direction1 b are compos$ 9 l>ge "p ( assort$ mat]ials4 ,9 contra/ ) o!r portions ( ! mora9al ridges !y lack ! prom95t bas9s kn[n z kettles4 ,o!r kames are high hills ( assort$ mat]ials n 9 direct association ) mora9es & believ$ to h be5 built up b5ea? glaci] wells or mills 7p4 #bgh74 ,outwa% pla9s4--,^u ! out] m>g9 ( ! mora9e is g5]ally to be f\nd a pla9 ( glacial 8outwa%0 compos$ ( s& or gravel deposit$ by ! braid$ /reams 7,fig4 #cjh1 p4 #bhj7 fl[+ f ! glaci] m>g94 ,su* pla9s1 :ile notably flat 7,fig4 #cch71 slope g5tly away f ! mora9e4 ,betwe5 ! outwa% pla9 & ! mora9e !re is sometimes f\nd a pit1 or fosse 7,fig4 #cji1 p4 #bha71 :]e a "p ( ! ice front 0 9 "p buri$ 9 its own outwa% 7,fig4 #cci74 ,illu/ration3 ,,fig4 #cdj4--,view look+ along an esk] 9 s\!rn ,ma9e 7aft] ,/one74 ,pitt$ pla9s & int]lobate mora9es4--,:]e glacial outwa% is conc5trat$ )9 a long & n>r[ rentrant1 sep>at+ glacial lobes1 /rips ( high pla9 are sometimes built up :i* ov]top ! o!r glacial deposits ( ! di/rict4 ,! s& & gravel :i* compose su* pla9s h a surface :i* is pitt$ by num]\s deep & m or less circul> lakes1 s t ! t]m 8pitt$ pla90 has be5 appli$ to !m4 ,! surface ( su* a pla9 /eadily rises t[>d its highe/ po9t 9 ! angle betwe5 ! ice lobes4 ,?\gh consi/+ almo/ entirely ( assort$ mat]ials1 & built up l>gely )\t ! ice m>g9s1 su* g5tly slop+ pitt$ plat=ms are describ$ z int]lobate mora9es4 ,^u a topographic map ! c\rse ( su* an int]lobate mora9e may (t5 be foll[$ by ! belts ( small pit lakes 7see ,fig4 #ccf74 ,illu/ration3 ,,fig4 #cda4--,outl9e map %[+ ! esk]s ( ,f9l& tr5d+ s\!a/]ly t[>d ! fe/oon$ mora9es at ! m>g9 ( ! ice4 ,! *>act]i/ic lakes ( a glaciat$ region appe> beh9d ! mora9es 7aft] ,j4 ,j4 ,s$]holm74 ,illu/ration3 ,,fig4 #cdb4--,small sket* maps %[+ ! relation%ips 9 size1 proportions1 & ori5tation ( druml9s & esk]s 9 s\!rn ,wiscons94 ,! esk]s are 9 solid black 7aft] ,ald574 ,esk]s4--,intra-mora9al features1 or ^? develop$ b5ea? ! glaci] b relatively ne> its m>g91 include ! 8s]p5t9e kame01 esk]1 or1 z x is call$ 9 ,sc&9avia1 ! os 7plural os>7 7,fig4 #cdj74 ,^! dim9utive ridges h a wid? seldom exce$+ a few rods1 & a height a few t5s ( feet at mo/1 b ) slightly s9u\s undulations !y may be foll[$ = t5s or ev5 hundr$s ( miles 9 ! g5]al direction ( ! local ice movem5t 7,fig4 #cda74 ,!y are compos$ ( poorly /ratifi$1 ?ick-b$d$ s&s1 gravels1 & 8work$ ov]0 mat]ials1 & are believ$ to h be5 =m$ by subglacial riv]s :i* fl[$ 9 tunnels b5ea? ! ice4 ,inasmu* z ! deposits 7 pil$ aga9/ ! ice walls1 ! b$s 7 di/urb$ at ! sides :5 ^! walls disappe>$1 & ! /ratification1 :i* 0 some:at ar*$ 9 ! beg9n+1 has be5 alt]$ by slid+ at bo? m>g9s4 ,z already /at$1 esk]s h n a g5]al di/ribution )9 ! glaciat$ area1 b are (t5 f\nd 9 great numb]s at specially favor$ localities4 ,=m$ z !y are b5ea? ! ice1 x is believ$ t _m h _! mat]ials r$i/ribut$ s soon z uncov]$ at ! glaci] m>g91 because ( ! vigor\s dra9age !re4 ,!y are ?us to be f\nd only at ^? favor$ localities :]e = "s reason bord] dra9age is less active1 or :]e ! ice end$ 9 a body ( wat]4 ,druml9s4--,a peculi> type ( small hill likewise f\nd beh9d ! m>g9al mora9e 9 c]ta9 favor$ di/ricts has ! =m ( an inv]t$ boat or canoe1 ! long axis ( :i* is p>allel to ! direction ( ice movem5t1 z is t ( ! esk] 7,fig4 #cdb74 ,unlike ! esk]1 ?is type ( hill is compos$ ( till1 & f be+ f\nd 9 ,irel& x is call$ a druml91 ! ,iri% ^w mean+ a little hill 7,fig4 #cdc74 ,druml9s are usually f\nd 9 gr\ps m or less radial & n f> beh9d ! out]mo/ mora9e1 to :i* _! radiat+ axes are p]p5dicul>4 ,! mann] ( _! =mation is involv$ 9 "s unc]ta9ty1 b x is cle> t !y h be5 =m$ b5ea? ! m>g9 ( ! glaci]1 & h be5 giv5 _! %ape by ! la/ glaci] :i* occupi$ ! di/rict4 ,! mutual relation%ips ( ne>ly all ! mold$ features result+ f cont95tal glaciation may be read f ,fig4 #cdd4 ,illu/ration3 ,,fig4 #cdc4--,view ( a druml91 %[+ an op5+ 9 ! till4 ,ne> ,bo/on1 ,massa*usetts 7aft] ,%al] & ,davis74 ,! %elf ice ( ! ice age4--,%elf ice1 su* z we h become famili> ) 9 ,ant>ctica z a m>g9al sn[-ice t]race float+ ^u ! sea1 no d\bt exi/$ dur+ ! ice age above ! ,gulf ( ,ma9e 7see ,fig4 #cbd1 p4 #bih71 & p]haps also ov] ! deep sea to ! we/w>d ( ,scotl&4 ,?\gh ! inl& ice probably cov]$ ! ,nor? ,sea1 & ^u ! ,am]ican side ( ! ,atlantic ! ,long ,isl& ,s\nd1 bo? ^! bas9s are s %all[ t ! ice mu/ h re/$ ^u ! bottom1 = nei!r is ( suffici5t dep? to entirely subm]ge "o ( ! high] ,european ca!drals4 ,illu/ration3 ,,fig4 #cdd4--,outl9e map ( ! front ( ! ,gre5 ,bay lobe ( ! late/ cont95tal glaci] ( ! ,unit$ ,/ates4 ,druml9s 9 solid black1 mora9es ) diagonal ha*ure1 outwa% pla9s & ! till pla9 or gr\nd mora9e 9 :ite 7aft] ,ald574 ,"* pr(iles4--,all surface features ref]able to cont95tal glaci]s1 :e!r c>v$ 9 rock or mold$ f loose mat]ials1 pres5t g5tly fl[+ outl9es :i* are convex upw>d 7,fig4 #cde74 ,! only def9ite features c>v$ f rock are ! ro*es m\tonnes1 ) _! flatt5$ %\ld]s1 :ile ! hillocks ^u mora9es & kames1 & ! druml9s z well1 approximate to ! same pr(ile4 ,! esk] 9 its cross sections is mu* ! same1 ?\gh its s]p5t9e ext5sion may (f] "s v>iety ( curvature :5 view$ f high] levels4 ,illu/ration3 ,,fig4 #cde4--;,"* pr(iles ref]able to cont95tal glaci]4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxii ,g5]al3-- ,,james ,,geikie4 ,! ,great ,ice ,age4 #c;d ed4 ,london1 #ahid1 pp4 #hej1 maps #ah4 ,,*amb]l9 & ,,salisbury4 ,geology1 vol4 #c1 #aijf1 pp4 #cbg-eaf4 ,,frank ,,lev]ett4 ,! ,ill9ois ,glacial ,lobe1 ,mon4 #ch1 ,u4 ,s4 ,geol4 ,surv41 #ahii1 pp4 #hag1 pls4 #cd2 ,glacial =mations & ,dra9age ,features ( ! ,erie & ,ohio ,bas9s1 ,mon4 #da1 ibid41 #aijb1 pp4 #hjb1 pls4 #be2 ,comp>ison ( ,nor? ,am]ican & ,european ,glacial ,deposits1 ,zeit4 f4 ,glets*]k41 vol4 #d1 #aiaj1 pp4 #bda-cae1 pls4 #a-e4 ,=m] glaciations previ\s to ,ice ,age3-- ,a4 ,,/rahan4 ,! ,glacial ,ph5om5a ( ,paleozoic ,age 9 ! ,v>ang] ,fjord1 ,qu>t4 ,j\r4 ,geol4 ,soc41 ,london1 vol4 #ec1 #ahig1 pp4 #acg-adf1 pls4 #h-aj4 ,,bailey ,,willis & ,,eliot ,,blackweld]4 ,rese>* 9 ,*9a1 ,pub4 #ed1 ,c>negie ,in/4 ,wa%+ton1 vol4 #a1 #aijg1 pp4 #bfg-bfi1 pls4 #cg-ch4 ,a4 ,p4 ,,coleman4 ,a ,l[] ,huronian ,ice ,age1 ,am4 ,j\r4 ,sci4 7#d71 vol4 #bc1 #aijg1 pp4 #ahg-aib4 ,w4 ,m4 ,,davis4 ,obs]vations 9 ,s\? ,africa1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ag1 #aijf1 pp4 #cgg-dej1 pls4 #dg-ed4 ,,david ,,:ite4 ,p]mo-,c>bonif]\s ,climatic ,*anges 9 ,s\? ,am]ica1 ,j\r4 ,geol41 vol4 #ae1 #aijg1 pp4 #fae-fcc4 ,driftless & drift areas3-- ,t4 ,c4 ,,*amb]l9 & ,r4 ,d4 ,,salisbury4 ,prelim9>y ,pap] on ! ,driftless ,areas ( ! ,upp] ,mississippi ,valley1 #f? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhe1 pp4 #aii-cbb1 pls4 #bc-bi4 ,r4 ,d4 ,,salisbury4 ,! ,drift1 its ,*>act]i/ics & ,relation%ips1 ,j\r4 ,geol41 vol4 #b1 #ahid1 pp4 #gjh-gbd1 #hcg-hea4 ,r4 ,h4 ,,:itbeck4 ,contra/s betwe5 ! ,glaciat$ & ! ,driftless ,portions ( ,wiscons91 ,bull4 ,geogr4 ,soc41 ,philadelphia1 vol4 #i1 #aiaa1 pp4 #aad-abc4 ,glaci] grav+s3-- ,t4 ,c4 ,,*amb]l94 ,! ,rock ,scor+s ( ! ,great ,ice ,invasions1 #g? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhh1 pp4 #adg-bdh1 pl4 #h4 ,! disp]sion ( ! drift3-- ,r4 ,d4 ,,salisbury4 ,notes on ! ,disp]sion ( ,drift ,copp]1 ,trans4 ,wis4 ,acad4 ,sci41 etc41 vol4 #f1 #ahhf1 pp4 #db-ej1 pl4 ,n4 ,s4 ,,%al]4 ,! ,conditions ( ,erosion b5ea? ,deep ,glaci]s1 bas$ ^u a ,/udy ( ! ,b[ld] ,tra9 f ,iron ,hill1 ,cumb]l&1 ,rhode ,isl&1 ,bull4 ,mus4 ,comp4 ,zol4 ,h>v4 ,coll41 vol4 #af1 ,no4 #aa1 #ahic1 pp4 #ahe-bbe1 pls4 #a-d & map4 ,,william ,h4 ,,hobbs4 ,! ,diamond ,field ( ! ,great ,lakes1 ,j\r4 ,geol41 vol4 #g1 #ahii1 pp4 #cge-chh1 pls4 #b 7also ,rept4 ,smi?son4 ,in/41 #aija1 pp4 #cei-cff1 pls4 #a-c74 ,glacial features3-- ,t4 ,c4 ,,*amb]l94 ,prelim9>y ,pap] on ! ,t]m9al ,mora9e ( ! ,second ,glacial ,epo*1 #c;d ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhc1 pp4 #bia-djb1 pls4 #bf-ce4 ,g4 ,h4 ,,/one4 ,glacial ,gravels ( ,ma9e & _! ,associat$ ,deposits1 ,mon4 #cd1 ,u4 ,s4 ,geol4 ,surv41 #ahii1 pp4 #dhi1 pls4 #eb4 ,w4 ,c4 ,,ald54 ,! ,delav5 ,lobe ( ! ,lake ,mi*igan ,glaci] ( ! ,wiscons9 ,/age ( ,glaciation & ,associat$ ,ph5om5a4 ,pr(4 ,pap4 ,no4 #cd1 ,u4 ,s4 ,geol4 ,surv41 #aijd1 pp4 #ajf1 pls4 #ae2 ,! ,druml9s ( ,s\!a/]n ,wiscons91 ,bull4 #bgc1 ,u4 ,s4 ,geol4 ,surv41 #aije1 pp4 #df1 pls4 #i4 ,w4 ,m4 ,,davis4 ,/ructure & ,orig9 ( ,glacial ,s& ,pla9s1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #a1 #ahij1 pp4 #aif-bjb1 pl4 #c2 ,! ,subglacial ,orig9 ( ,c]ta9 ,esk]s1 ,proc4 ,bo/4 ,soc4 ,nat4 ,hi/41 vol4 #ce1 #ahib1 pp4 #dgg-dii4 ,f4 ,p4 ,,gulliv]4 ,! ,newtonville ,s& ,pla91 ,j\r4 ,geol41 vol4 #a1 #ahic1 pp4 #hjc-hab4 ,,*apt] ,,xxiii ,,glacial ,,lakes ,,:i* ,,m>k$ ,,! ,,decl9e ,,( ,,! ,,la/ ,,ice ,,age ,illu/ration3 ,,fig4 #cdf4--,! ,ill9ois ,riv] :]e x passes ?r\gh ! out] mora9e at ,peoria1 ,ill9ois1 %[+ ! flood pla9 ( ! anci5t /ream z an elevat$ t]race into :i* ! mod]n /ream has cut its gorge 7aft] ,gold?wait74 ,int]f]5ce ( glaci]s ) dra9age4--,e advance & e retreat ( a cont95tal glaci] has be5 m>k$ by a complex s]ies ( episodes 9 ! hi/ory ( e riv] ^: t]ritory x has invad$4 ,:5ev] ! valley 0 ent]$ f ! direction ( its divide1 ! effect ( ! advanc+ ice front has g5]ally be5 to swell ! wat]s ( ! riv] into floods to :i* ! pres5t /reams be> little resemblance 7,fig4 #cdf74 ,because ( ! excessive melt+1 ?is has be5 ev5 m true ( ! ice retreat1 b "h :5 ! ice front retir$ up ! valley t[>d ! divide4 ,a suffici5tly /rik+ example is furni%$ by ! ,waba%1 ,kaskaskia1 ,ill9ois1 & o!r /reams to ! s\?w>d ( ! divide :i* surr\nds ! bas9 ( ! ,great ,lakes 7,fig4 #cdg74 ,illu/ration3 ,,fig4 #cdg4--;,broadly t]rac$ valleys outside ! divide ( ! ,/4 ,lawr5ce bas91 :i* rema9 to m>k ! floods t issu$ f ! late/ cont95tal glaci] dur+ its retreat 7aft] ,lev]ett74 ,:]ev] ! relief 0 small !re occurr$ 9 ! imm$iate vic9ity ( ! ice front a tempor>y div]sion ( ! /reams by ! p>allel mora9es1 s t ! curr5ts t5d$ to p>allel ! ice front4 ,?is tempor>y div]sion kn[n z 8bord] dra9age0 0 br\ght to a close :5 ! p>tially imp\nd$ wat]s _h1 by cutt+ _! way ?r\gh ! mora9es1 e/abli%$ m p]man5t valleys 7,fig4 #cdh74 ,tempor>y lakes due to ice block+4--,:5ev]1 on ! contr>y1 ! advanc+ ice front ent]$ a valley f ! direction ( its m\?1 or a retreat+ ice front retir$ d[n ! valley1 q diff]5t results foll[$1 s9ce ! wat]s 7 n[ imp\nd$ by ! ice front s]v+ z a dam4 ,?\gh ! hi/ories ( su* block+ ( riv]s are (t5 q complex1 ! pr9ciples :i* und]lie !m are 9 reality simple en\gh4 ,( ! lakes =m$ dur+ advanc+ hemicycles ( glaciation1 & ( all save ! late/ rec$+ hemicycle1 no satisfactory records are pres]v$1 = ! reason t ! lake bea*es & ! lake deposits 7 lat] di/urb$ & buri$ by ! ov]rid+ ice %eets4 ,we h1 h[ev]1 e reason to suppose t ! hi/ories ( ea* ( ^! hemicycles 7 9 e way z complex & int]e/+ z t ( ! "o :i* we are p]mitt$ to /udy4 ,illu/ration3 ,,fig4 #cdh4--;,bord] dra9age ab\t ! retreat+ ice front s\? ( ,lake ,erie4 ,! /ippl$ areas are ! mora9al ridges & ! ha*ur$ b&s ! valleys ( bord] dra9age 7aft] ,lev]ett74 ,z an introduction to ! /udy ( ! ice-block$ lakes ( ,nor? ,am]ica1 & to set =? z cle>ly z may be ! fundam5tal pr9ciples ^u :i* su* lakes are dep5d5t1 we %all consid] 9 "s detail ! late glacial hi/ory ( c]ta9 ( ! ,scotti% gl5s1 s9ce _! area is s small & ! relief s /rong t relation%ips are m easily se52 x is1 s to speak1 a pocket edition ( ! hi/ory ( ! m ext5d$ glacial lakes4 ,illu/ration3 ,,fig4 #cdi4--,! 8p>allel roads0 ( ,gl5 ,roy 9 ! s\!rn highl&s ( ,scotl& 7aft] ,jamieson74 ,! 8p>allel roads0 ( ! ,scotti% gl5s4--,9 a numb] ( neighbor+ gl5s )9 ! s\!rn highl&s ( ,scotl& !re are f\nd fa9t t]races ^u ! gl5 walls :i* "u ! "n ( ! 8p>allel roads0 7,fig4 #cdi7 h (f]$ a vex$ problem to sci5ti/s4 ,( ! _m sci5ti/s :o long attempt$ to expla9 !m1 ?\gh 9 va91 0 ,*>les ,d>w91 ! fa!r ( mod]n evolution4 ,he (f]$ x z 8 view t ! 8roads0 7 bea*es =m$ at a "t :5 ! sea ent]$ ! gl5s & /ood at ^! levels4 ,:51 h[ev]1 ,jamieson's /udies _h discov]$ _! true hi/ory1 ,d>w91 ) a frankness *>act]i/ic ( "s ( ! greate/ sci5ti/s1 admitt$ h[ f> a/ray he _h be5 9 8 reason+4 ,let u1 !n1 fir/ exam9e ! facts1 & lat] _! int]pretation4 ,! map ( ,fig4 #cej w suffice to set =? ) suffici5t cle>ness ! c\rse ( ! sev]al 8roads40 ,^! 8roads0 are f\nd 9 a numb] ( gl5s tribut>y to ,lo* ,lo*y1 & ( ! ?ree neighbor+ valleys1 ,gl5 ,roy has ?ree1 ,gl5 ,gla/] two1 & ,gl5 ,spean "o 8road40 ,! facts ( greate/ significance 9 arriv+ at _! int]pretation relate to _! elevations ) ref]5ce to ! passes at ! valley heads1 _! abrupt t]m9ations d[n-valleyw>d1 & ! mora9ic accumulations :i* are f\nd :]e !y t]m9ate4 ,! s+le 8road0 ( ,gl5 ,spean is f\nd at an elevation ( #hih feet1 a height :i* corresponds to t ( ! pass or col at ! head ( its valley & to ! l[e/ ( ! 8roads0 9 bo? ,gl5s ,gla/] & ,roy4 ,simil>ly ! upp] ( ! two 8roads0 9 ,gl5 ,gla/] is at ! height ( ! pass at its head 7#ajge feet7 & corresponds 9 elevation to ! middle "o ( ! ?ree 8roads0 9 ,gl5 ,roy4 ,la/ly1 ! highe/ ( ! 8roads0 9 ,gl5 ,roy is f\nd at an elevation ( #aaea feet1 ! height ( ! col at ! head ( ! ,gl54 ,9 ! neighbor+ ,gl5 ,gloy is a /ill high] 8road0 correspond+ likewise 9 elevation to t ( ! pass ?r\gh :i* x connects ) ,gl5 ,roy4 ,illu/ration3 ,,fig4 #cej4--,map ( ,gl5 ,roy & neighbor+ valleys ( ! ,scotti% highl&s ) ! s-call$ 8roads0 ent]$ 9 heavy l9es4 ,gl5s ,roy1 ,gla/]1 & ,spean h ?ree 8roads01 two 8roads01 & "o 8road01 respectively 7aft] ,jamieson74 ,to come n[ to ! explanation ( ! 8roads01 x may be said at ! outset t !y are1 z ,d>w9 suppos$1 bea* t]races cut by waves1 n z he believ$ ( ! ocean1 b ( lakes :i* once fill$ portions ( ! gl5s :5 glaci]s proce$+ f ,b5 ,nevis to ! s\?we/w>d 7 block+ _! l[] portions4 ,! sev]al episodes ( ?is lake hi/ory w be cle> f a /udy ( ! ?ree successive ideali/ic diagrams 9 ,fig4 #cea4 ,illu/ration3 ,,fig4 #cea4--,?ree successive diagrams to set =? 9 ord] ! late glacial lake hi/ory ( ! ,scotti% gl5s4 ,to d]ive ! pr9ciples und]ly+ ?is hi/ory1 x is at once se5 t all *anges are initiat$ by ! retirem5t ( ! ice front to su* a po9t t x unblocks = ! wat]s ( a lake an outlet t is l[] ?an ! "o 9 s]vice at ! "t4 ,?is is ! pr9ciple :i* expla9s ne>ly all episodes ( glacial lake hi/ory4 ,?us1 :5 ! ice front _h retir$ s z to op5 direct connections betwe5 ,gl5 ,roy & ,gl5 ,gla/]1 ! col at ! head ( ,gl5 ,roy 0 ab&on$ z an outlet1 & ! wat]s fell to ! level fix$ = ,gl5 ,gla/]4 ,a /ill fur!r retirem5t at la/ op5$ direct connection betwe5 ,gl5 ,gla/] & ,gl5 ,spean1 s t ! lake common to ,gl5s ,gla/] & ,roy fell to ! level ( ! col :i* 0 ! outlet ( ! ,spean valley at ! "t4 ,?is /age cont9u$ until ! ice front _h retir$ s f> t ! wat]s dra9$ naturally d[n ! riv] ,spean to ,lo* ,lo*y & !nce to ! ocean4 ,illu/ration3 ,,fig4 #ceb4--;,h>ve/+ "t on ! f]tile floor ( ! glacial ,lake ,agassiz 7aft] ,h[ell74 ,only 9 _! f> gr&] scale & 9 ! less] relief ( ! l& ov] :i* !y =m$1 d ! complex hi/ories ( ! great ice-block$ lakes ( ,nor? ,am]ica diff] f ^! little valley lakes ^: bea*es may be visit$ & ! relation%ips work$ out1 ?anks to ,jamieson1 9 a s+le day's /roll+4 ,illu/ration3 ,,fig4 #cec4--,map ( ,lake ,agassiz 7aft] ,upham74 ,! glacial ,lake ,agassiz4--,! gr&e/ ( ! tempor>y lakes ref]able to block+ by ! cont95tal glaci]s ( ! ice age mu/ be look$ = 9 ! l>ge/ valleys t lay )9 ! t]ritory invad$ & :i* normally dra9 t[>d ! retir+ ice front4 ,9 ,nor? ,am]ica ^! riv]s are ! ,r$ ,riv] ( ! ,nor? 9 ,m9nesota1 ! ,dakotas1 & ,manitoba2 & ! ,/4 ,lawr5ce ,riv] sy/em4 ,to ! ice dam :i* lay across ! ,r$ ,riv] valley we owe ! f]tility ( t va/ pla9 ( lake deposits :]e is to-day ! mo/ int5sive :eat f>m+ ( ! nor?we/ 7,fig4 #ceb74 ,lakes ,w9nipeg1 ,w9nipegoosis1 & ,manitoba1 & ! ,lake ( ! ,woods1 are all t n[ rema9 ( ?is greate/ ( ! glacial lakes1 :i* 9 honor ( ! di/+ui%$ f\nd] ( ! glacial !ory has be5 call$ ,lake ,agassiz 7,fig4 #cec74 ,) _! natural outlet block$ by ! ice 9 nor!rn ,manitoba & ,keewat91 ! wat]s ( ! ,r$ 7 swoll5 by melt+ f ! retir+ glaci] & spread ov] a va/ area be=e f9d+ a s\!rn outlet along ! c\rse ( ! pres5t ,lake ,trav]se & ! valley ( ! ,m9nesota ,riv]4 ,along ?is r\te !re fl[$ a mighty flood :i* c>v$ out a broad valley _m times too l>ge = ! ,m9nesota1 its pres5t occupant1 & ?is giant prehi/oric riv] has be5 call$ ! ,w>r5 ,riv] 7,fig4 #ced74 ,illu/ration3 ,,fig4 #ced4--,map ( ! s\!rn end ( ! ,lake ,agassiz bas91 %[+ ! position ( "s ( ! bea*es & ! outlet ?r\gh ! =m] ,w>r5 ,riv] 7aft] ,upham74 ,illu/ration3 ,,fig4 #cee4--,n>r[s ( ! ,w>r5 ,riv] bel[ ,big ,/one ,lake1 :]e x pass$ betwe5 jaws ( h>d granite & gneiss 7aft] ,upham74 ,illu/ration3 ,,fig4 #cef4--,map ( ! valley ( ! ,w>r5 ,riv] 9 ! vic9ity ( ,m9neapolis1 ) ! "y valley ( ! ,mississippi ent]+ x at ,=t ,snell+ 7aft] ,s>deson74 ,x is int]e/+ to foll[ ?is anci5t wat]way & to discov] t1 l our normal1 pres5t-day /reams1 x 0 held up 9 n>r[s :]ev] outcropp+s ( h>d] rock _h con/rict$ its *annel 7,fig4 #cee74 ,! upp] end ( ! ,w>r5 ,riv] valley is n[ occupi$ by ! long & relatively n>r[ ,lakes ,trav]se & ,big ,/one1 ea* ! result ( block+ by delta deposits :]e a tribut>y /ream has em]g$ into ! valley1 b ?is gigantic *annel cont9ues d[n to & beyond ,m9neapolis1 occupi$ z f> z ,=t ,snell+ by ! ,m9nesota ,riv]--a m]e pygmy comp>$ to its pr$ecessor4 ,to ! e>ne/ /ud5t ( glacial geology !re c be few sights m impressive ?an are obta9$ by /&+ at ,=t ,snell+1 j above ! conflu5ce ( ! ,m9nesota & ! ,mississippi riv]s1 & survey+ fir/ ! /eep & n>r[ valley ( ! ,mississippi above ! junction1--a /ream fitt$ to its valley = ! simple reason t x has c>v$ x1--& !n gaz+ up & d[n t broad valley 9 :i* ! great ,w>r5 ,riv] once fl[$ maje/ically to ! sea1 n[ ! b$ ( ! ,m9nesota above ! ,=t & ( ! ,mississippi bel[ x 7,fig4 #cef74 ,illu/ration3 ,,fig4 #ceg4--,portion ( ! ,h]man quadrangle ( ,m9nesota1 %[+ ! position ( ! ,h]man bea* on ! %ore ( ! =m] ,lake ,agassiz4 ,! lake bas9 is to ! left1 & ! pitt$ mora9al deposits appe> to ! "r 7,u4 ,s4 ,g4 ,s474 ,j z ! 8p>allel roads0 ( ,gl5 ,roy1 roads 9 "n only1 are ! bea*es ( e>li] glacial lake /ages1 s 9 ,lake ,agassiz we h p>allel bea*es ( ! b>ri] type :i* are (t5 roads 9 fact z well z 9 "n1 & :i* m>k ! /ages ( successive lakes )9 ?is va/ bas94 ,! ,h]man bea*1 correspond+ to ! highe/ level ( ! lake1 is ?us a %>p topographic b\nd>y betwe5 lake deposits & mora9al accumulations1 & is fur!r itself a well-m>k$ topographic feature compos$ ( wave-wa%$ & h5ce well-dra9$ mat]ials 7,fig4 #ceg74 ,f>m]s ( ! di/rict h be5 quick to realize t ^! level & slightly elevat$ ridges lack ! clay :i* w\ld r5d] !m muddy 9 ! wet seasons1 & are ?us ideally adapt$ = roads4 ,!y h 9 _m sections be5 ?us us$ ov] long /ret*es & are kn[n z ! 8ridge roads40 ,episodes ( ! glacial lake hi/ory )9 ! ,/4 ,lawr5ce valley4--,)9 ?is great dra9age bas9 x has app>5tly be5 possible to read ! records ( ea* /age 9 ! late/ lake hi/ory--complex z ?is has be54 ,we h only to recall ! lake /ages cit$ f ! ,scotti% gl5s & rememb] t ea* new /age 0 begun 9 a retirem5t ( ! glaci] front :i* unblock$ an outlet ( l[] level ?an ! la/4 ,?is sequ5ce might1 h[ev]1 h be5 v>i$ by a tempor>y readvance ( ! ice1 z inde$ once occurr$ 9 ! ,huron-,erie lobe ( ! great ,nor? ,am]ican glaci]4 ,illu/ration3 ,,fig4 #ceh4--,! cont95tal glaci] ( ,nor? ,am]ica 9 an e>ly /age ( its recession1 :5 x cov]$ ! entire ,/4 ,lawr5ce dra9age bas94 ,! da%$ l9e is ! approximate position ( ! divide 7bas$ on a map by ,gold?wait74 ,illu/ration3 ,,fig4 #cei4--,outl9e map ( ! e>ly ,lake ,maumee1 ) ! bord]+ mora9e & ! wat]-laid mora9e rema9+ on ! site ( ! =m] ice cliff4 ,! cresc5tic lakes ( ! e>li] /ages4--,s long z ! glaci] cov]$ ! entire dra9age bas9 ( ! ,/4 ,lawr5ce ,riv] sy/em1 all wat] 0 freely dra9$ away by /reams :i* fl[$ away f ! ice front 7,fig4 #ceh74 ,s soon1 h[ev]1 z at any po9t ! front _h retir$ beh9d ! divide1 imp\nd+ ( ! wat]s mu/ locally h occurr$4 ,lakes ( ?is type are to-day to be se5 9 ,gre5l& & 9 ! s\!rn ,&es2 & ?\gh ^u a dim9utive scale1 "s idea ( _! aspect may be obta9$ f ! appe>ance ( ! ,mrjel5 ,lake ( ,switz]l&1 "h block$ by a m\nta9 glaci] 7,fig4 #ddf1 p4 #daa74 ,)9 all areas ( small relief1 su* z ! prairie c\ntry surr\nd+ ! pres5t ,laur5tian lakes1 ! e>li] & small] /ages ( su* ice-block$ lakes are g5]ally cresc5tic 9 outl9e4 ,?is is because a mora9e 9 mo/ cases =ms ! l& m>g9 ( ! lake1 & because ! ice cliff ^u ! opposite bord]1 al?\gh some:at /raight5$1 z a consequ5ce ( wave-cutt+ & iceb]g =mation1 /ill reta9s ! convex outl9es *>act]i/ic ( ice lobes 7,fig4 #cei74 ,illu/ration3 ,,fig4 #cfj4--,map to %[ ! fir/ /ages ( ! ice-damm$ lakes )9 ! ,/4 ,lawr5ce bas9 7aft] ,lev]ett & ,taylor74 ,)9 ea* ( ! ,great ,lake bas9s a cresc5tic lake e>ly appe>$ at t end ( ! depression :i* 0 fir/ uncov]$ by ! glaci]3 ,lake ,dulu? 9 ! ,sup]ior bas91 ,lake ,*icago 9 ! ,mi*igan bas91 & ,lake ,maumee 9 ! ,huron-,erie bas9 7,fig4 #cfj74 ,we may n[1 ) pr(it1 trace ! successive episodes ( ! glacial lake hi/ory1 consid]+ = ! e>li] /ages ^? *anges :i* occurr$ )9 ! ,huron-,erie bas91 s9ce1 ^! are 9 ess5tial respects l ^? ( ! ,mi*igan & ,sup]ior bas9s1 al?\gh work$ out 9 great] detail4 ,lake ,*icago mu/1 h[ev]1 be br\ght into consid]ation1 s9ce 9 all save ! e>lie/ & ! lat] /ages1 ! wat]s f ! ,huron-,erie depression 7 dis*>g$ ?r\gh ! ,gr& ,riv] into ?is lake & !nce by ! s-call$ 8,*icago outlet0 into ! ,mississippi 7plate #bj ,a74 ,! e>ly ,lake ,maumee4--,! area1 outl9e1 & outlet ( ?is lake are indicat$ ^u ,fig4 #cfj4 ,its anci5t bea*es h be5 trac$1 z well z ! wat]-laid mora9e b5ea? its =m] ice cliff2 & no obs]vant travel] :o %\ld take 8 way d[n ! anci5t outlet f ,=t ,wayne1 ,indiana1 pa/ ! t[n ( ,hunt+ton1 c\ld fail to be impress$ by its size1 sugge/+ z x does ! great volume ( wat] :i* mu/ once h fl[$ along x4 ,n[ a *annel a mile or m 9 wid?1 its b$ = ! tw5ty-five miles betwe5 ,=t ,wayne & ,hunt+ton may be se5 f ! tracks ( ! ,waba% ,railway z a s]ies ( swamps m]ely1 :ile at ,hunt+ton ! ,waba% riv] ent]s by a "y ,v-%ap$ valley at ! side1 mu* z ! ,mississippi em]ges into ! old *annel ( ! ,w>r5 ,riv] at ,=t ,snell+1 ,m9nesota 7see p4 #cbg74 ,! ,huron ,riv] ( s\!rn ,mi*igan1 :i* n[ dis*>ges into ,lake ,erie1 !n f\nd its l[] c\rse block$ by ! glaci] & 0 ?us compell$ to f9d a s\!rly direct$ *annel n[ easily foll[$ to ! nor!rn horn ( ! cresc5t ( ,lake ,maumee4 ,! lat] ,lake ,maumee4--,:5 ! ice lobe _h retir$ its front suffici5tly1 an outlet l[] ?an t at ,=t ,wayne 0 uncov]$ pa/ ! city ( ,imlay1 ,mi*igan1 into ! ,gr& ,riv]1 & !nce ?r\gh ,lake ,*icago & its outlet into ! ,mississippi4 ,?is old outlet s\? ( ,*icago foll[s ! c\rse ( ! pres5t ,dra9age ,canal & ! l9e ( ! ,*icago ,alton ,railway4 ,! travel] j\rney+ s\?w>d by tra9 f ,*icago has ?us ! opportunity ( obs]v+ fir/ ! bea*es ( ! =m] lake1 & !n ! sev]al *annels :i* 7 jo9$ 9 ! ma9 outlet at ! /ation ( ,sag 7plate #bj ,a74 ,illu/ration3 ,,fig4 #cfa4--,outl9e map ( ! lat] ,lake ,maumee & ( its 8,imlay outlet0 to ,lake ,*icago 7aft] ,lev]ett74 ,9 ?is /age ( our hi/ory ,lake ,maumee pu%$ a %runk arm up pa/ ! site ( ,ypsilanti 9 ,mi*igan 7,fig4 #cfa71 ! well-m>k$ bea* be+ f\nd on ,summit ,/reet opposite ! ,/ate ,normal ,college4 ,! ,huron ,riv]1 :i* 9 ! fir/ lake /age _h foll[$ ! valley n[ occupi$ by ! ,rais9 ,riv] s\?w>d into ,indiana1 n[ dis*>g$ directly into a bay ^u ?is arm ( ,lake ,maumee1 & s =m$ a delta at ,ann ,arbor4 ,illu/ration3 ,,fig4 #cfb4--,outl9e map ( ,lakes ,:ittlesey & ,sag9aw 7aft] ,lev]ett74 ,illu/ration3 ,,fig4 #cfc4--,map ( ! glacial ,lake ,w>r51 ! la/ ( ! lakes 9 ! ,huron-,erie bas91 :i* dis*>g$ ?r\gh ! 8,gr& ,riv] outlet0 into ! ,mississippi 7aft] ,lev]ett74 ,lakes ,arkona & ,:ittlesey4--,! ice front 9 ! ,huron-,erie bas9 n[ retir$ s f> t ! imp\nd$ wat]s1 in/ead ( foll[+ ! m direct 8,imlay outlet0 to ! ,gr&1 pass$ at a l[] level completely ar\nd 8! ?umb0 ( ,mi*igan into ! ,sag9aw bas94 ,mean:ile a cresc5t-%ap$ lake _h develop$ 9 t bas91 s t n[ ! wat]s ( ! ,maumee bas9 7 jo9$ to ^? 9 ! ,sag9aw bas9 z a common lake1 j z ! l[]+ ( ! wat]s 9 ,gl5 ,roy caus$ a union ) ^? ( ,gl5 ,gla/] 9 ! example cit$ = illu/ration4 ,our records ( ?is ?ird ,nor? ,am]ican lake /age1 ref]r$ to z ,lake ,arkona1 are h[ev] mo/ imp]fect1 = ! reason t x 0 foll[$ by a readvance ( ! ice front :i* clos$ ! passage ar\nd 8! ?umb0 & rais$ ! level ( ! wat]s until an outlet 0 f\nd pa/ ! t[n ( ,ubly at a l[] level ?an ! 8,imlay outlet40 ,:5 ! wat]s ( a lake are ?us ris+1 /rong bea* =mations result1 & ^? ( ?is /age1 :i* is kn[n z ! ,lake ,:ittlesey /age1 are mu* ! /ronge/ t are f\nd )9 ! ,huron-,erie bas94 ,trac$ = "s ?ree hundr$ miles entirely ar\nd ! s\!rn & we/]n m>g9s ( ,lake ,erie1 ?is bea* is = mu* ( ! di/ance ! fam\s 8ridge road0 7,fig4 #cfb74 ,lake ,w>r54--,z ! ice advance :i* _h produc$ ,lake ,:ittlesey came to an end1 ! normal recession 0 resum$ & a lake once m =m$ z a body common to ! ,sag9aw & ,erie bas9s4 ,?is lake1 kn[n z ,lake ,w>r51 ext5d$ a %runk arm f> ea/w>d along ! ice front into we/]n ,new ,york1 ?\gh x 0 /ill block$ f ent]+ ! great ,mohawk valley 7,fig4 #cfc74 ,illu/ration3 ,,fig4 #cfd4--,map ( ! ,glacial ,lake ,algonqu9 7aft] ,lev]ett74 ,lakes ,iroquois & ,algonqu94--,x mu/ be evid5t t t[>d ! close ( ! ,lake ,w>r5 /age a pr(\nd *ange 0 imm95t--a transf] ( ! glacial wat]s f _! c\rse to ! ,mississippi & ! ,gulf to ! tr5* :i* crosses ,new ,york ,/ate & ent]s ! ,atlantic4 ,s soon z ! ice front _h retir$ suffici5tly to lay b>e ! b$ ( ! ,mohawk1 an outlet 0 f\nd by ?is r\te & its cont9uation d[n ! ,hudson valley to ! sea4 ,! ,lake ,ont>io bas9 n[ became occupi$ by a consid]ably l>g] wat] body kn[n z ,lake ,iroquois1 & ! ?ree upp] lakes1 !n jo9$ z ,lake ,algonqu91 dis*>g$ _! comb9$ wat]s into ,lake ,iroquois at fir/ ?r\gh a great *annel n[ /rongly m>k$ across ,ont>io 9 ! c\rse ( ! ,tr5t ,riv] & ,lake ,simcoe1 ! s-call$ 8,tr5t outlet40 ,at ?is "t a small] ,lake ,erie probably occupi$ ! bas9 ( t lake1 & lat] ! ,tr5t outlet 0 ab&on$ = ! ,port ,huron outlet 7,fig4 #cfd74 ,illu/ration3 ,,fig4 #cfe4--,outl9e map ( ! ,nipiss+ ,great ,lakes ) _! outlet pa/ ,nor? ,bay into ! ,*ampla9 ,sea4 ,! ,nipiss+ ,great ,lakes4--,we h n[ foll[$ ! ice front /ep by /ep 9 its retreat across ! valley ( ! ,/4 ,lawr5ce sy/em4 ,! successive unblock+ ( outlets (f]s b "o fur!r possibility--! op5+ ( ! ,fr5* ,riv]-,nipiss+ ,lake-,ottawa ,riv]1 or 8,nor? ,bay outlet40 ,?\gh n s to-day1 ! b$ ( ?is anci5t *annel 0 !n mu* l[] ?an t ( ! 8,mohawk outlet01 & s soon z ! glaci] _h 9 its retreat uncov]$ ?is nor!rn *annel1 ! wat]s ( ! upp] lakes dis*>g$ ?r\gh x pa/ ! site ( ,ottawa & into an arm ( ! sea :i* !n occupi$ ! l[] ,/4 ,lawr5ce valley & has be5 call$ ! ,*ampla9 ,gulf or ,sea 7,fig4 #cfe74 ,! level ( ! wat]s 0 l[]$ & ! area ( ! lakes correspond+ly r$uc$4 ,! read] :o has _h no opportunity to obs]ve ^! anci5t *annels :i* c>ri$ ! swoll5 wat]s ( ! =m] glaci] lakes1 w f9d x int]e/+ to consid] t e "o ( !m has be5 fix$ ^u by eng9e]s = improvem5t z artificial wat]ways4 ,?us we h ! ,ill9ois ,dra9age ,canal & project$ %ip canal along ! 8,*icago outlet01 ! project$ ,mississippi-,lake ,erie ,canal along ! 8,=t ,wayne outlet01 ! ,gr& ,riv] canal project to connect ,lake ,mi*igan & ,sag9aw ,bay along ! c\rse ( ! 8,gr& ,riv] outlet01 ! ,tr5t ,canal along ! 8,tr5t outlet01 ! ,erie ,canal along ! 8,mohawk outlet01 &1 la/ly1 ! propos$ ,georgian ,bay %ip canal to ! ocean along ! 8,nor? ,bay0 or 8,nipiss+ outlet40 ,summ>y ( lake /ages4--,we h omitt$ 9 ?is summ>y ( late lake hi/ory 9 ! ,laur5tian bas9 all ! less important lake /ages1 includ+ "s ( a transitional nature :i* 7 repres5t$ by bea*es & outlets easily trac$ to-day4 ,?is is because x is an outl9e only :i* x seems be/ to pres5t1 & ! episodes ( ?is abridg$ hi/ory may be tabulat$ z foll[s3 ,,episodes ,,( ,,glacial ,,lake ,,hi/ory ,,mississippi ,,dra9age ,lake ,maumee 7e>ly71 ,=t ,wayne outlet4 ,lake ,maumee 7late71 ,imlay ,city outlet4 ,lake ,arkona1 8?umb0 outlet4 ,lake ,:ittlesey 7) readvance ( glaci]71 ,ubly outlet4 ,lake ,w>r51 8?umb0 outlet4 ,,atlantic ,,dra9age ,lakes ,iroquois & ,algonqu9 7e>ly71 ,tr5t & ,mohawk outlets4 ,lakes ,iroquois & ,algonqu9 7late71 ,port ,huron & ,mohawk outlets4 ,nipiss+ ,great ,lakes1 ,nor? ,bay outlet4 ,p]man5t *anges ( dra9age affect$ by ! glaci]4--,:ile ! lake hi/ory :i* we h sket*$ is made up ( episodes :i* endur$ only :ile ! ice front lay betwe5 c]ta9 /ations ^u its retreat1 !re 7 none ! less br\ght ab\t ! pr(\nde/ ( p]man5t modifications 9 ! dra9age ( ! region4 ,x is possible to re/ore ^u maps 9 "p only ! preglacial dra9age ( ! nor? c5tral /ates1 b we "k at lea/ t x 0 z diff]5t z may be f t :i* we f9d to-day4 ,! ,miss\ri & ! ,ohio take _! c\rses to-day along ! m>g9 ( ! glaciat$ area z an inh]itance f ! bord] dra9age ( ! ice age4 ,)9 ! glaciat$ regions riv]s h 9 _m cases be5 compell$ by mora9al ob/ructions to ent] ^u new c\rses1 or ev5 to travel 9 ! opposite direction along _! =m] *annels4 ,9 di/ricts ( consid]able relief ^! div]sions h sometimes caus$ ! /reams to plunge ov] ! walls ( deep valleys1 & x may tru?fully be said t we owe mu* ( our mo/ beautiful sc5]y 9 "p to ! c>v+ & mold+ ( glaci]s1 b especially to ! cascades & wat]falls directly due to _! int]f]5ce ) dra9age4 ,illu/ration3 ,,fig4 #cff4--,probable preglacial dra9age ( ! upp] ,ohio region 7aft] ,*amb]l9 & ,lev]ett74 ,_m div]sions or rev]sals ( =m] dra9age l9es1 ?r\gh ! influ5ce ( ! cont95tal glaci]1 are at once sugge/$ by ! abnormal /ream c\rses1 :i* appe> ^u our maps1 & ! correctness ( ^! sugge/ions may (t5 be confirm$ by v simple obs]vations made ^u ! gr\nd4 ,! map ( ,fig4 #cff %[s h[ diff]5t 0 ! preglacial dra9age ( ! upp] ,ohio region f t ( to-day4 ,an int]e/+ additional example is furni%$ by ! ,/ill ,riv] :i* 9 ,connecticut is tribut>y to ! ,f>m+ton1 & is no less rem>kable = its abnormal nor!rly c\rse & sluggi% curr5t p]petuat$ 9 its "n1 ?an = ! way 9 :i* x is jo9$ to ! ,f>m+ton sy/em 7,fig4 #cfg ,a74 ,a c>eful /udy ( ! di/rict has %[n t ! ,/ill ,riv] 0 once a "p ( ! ,naugatuck & fl[$ s\?w>d t[>d ,long ,isl& ,s\nd l o!r riv]s ( ! di/rict 7,fig4 #cfg ,b74 ,x possess$1 h[ev]1 an advantage 9 a n>r[ belt ( s(t] rock along its c\rse1 & because ( ?is advantage x captur$ a portion ( "o ( ! tribut>ies to ! ,f>m+ton 7,fig4 #cfg ,c74 ,! cont95tal glaci] lat] cov]$ ! region1 & on its retreat laid d[n mora9al ob/ructions directly across ?is riv] & also at ! head ( ! sev]$ arm ( ! ,f>m+ton tribut>y 7,fig4 #cfg ,d74 ,! n[ imp\nd$ wat]s f\nd _! l[e/ outlet ne> ,s&y ,brook1 & 9 wat]falls & cascades ! n[ rev]s$ riv] falls "o hundr$ feet to ! b$ ( t /ream4 ,) ! aid ( ! excell5t topographic maps :i* are n[ suppli$ by a g5]\s gov]nm5t at a m]ely nom9al price1 su* bits ( rec5t hi/ory may be read at _m places )9 ! glaciat$ region4 ,illu/ration3 ,,fig4 #cfg4--;,diagrams to illu/rate ! episodes 9 ! rec5t hi/ory ( ! ,/ill ,riv] tribut>y to ! ,f>m+ton 9 ,connecticut4 ,a1 pres5t dra9age2 ,b1 e>ly /age2 ,c1 aft] capture ( a tribut>y to ! ,f>m+ton2 ,d1 aft] block+ by mora9al ob/ructions ( ! ice age4 ,glacial ,lake ,ojibway 9 ! ,hudson ,bay dra9age bas94--,:5 by pass+ ov] ! 8height ( l&0 9 nor!rn ,ont>io ! greatly r$uc$ cont95tal glaci] _h vacat$ ! bas9 ( ,/4 ,lawr5ce dra9age1 x 0 9 a position to imp\nd ^? wat]s :i* normally dra9$ to ,hudson ,bay4 ,! lake :i* !n came into exi/5ce has be5 call$ ,lake ,ojibway & 0 ! late/ ( ! entire s]ies4 ,?\gh ( b rec5t discov]y 9 a c\ntry till lately a trackless wild]ness1 its ext5sion seems to h be5 t ( ! clay b$s suit$ = f>m+4 ,! bea*es & outlets rema9 to be mapp$ :5 ! c\ntry has be5 made m easily accessible4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxiii ,p>allel roads ( ,gl5 ,roy3-- ,,*>les ,,d>w94 ,obs]vations on ! ,p>allel ,roads ( ,gl5 ,roy & ( ,o!r ,p>ts ( ,lo*ab] 9 ,scotl&1 ) an attempt to prove t !y are ( ,m>9e ,orig91 ,phil4 ,trans41 vol4 #h1 #ahci1 pp4 #ci-hb4 ,,l\is ,,agassiz4 ,geological ,sket*es1 ,bo/on1 #ahgf1 vol4 #b1 pp4 #cb-gf4 ,t4 ,t4 ,,jamieson4 ,on ! ,p>allel ,roads ( ,gl5 ,roy & _! ,place 9 ! ,hi/ory ( ! ,glacial ,p]iod1 ,qu>t4 ,j\r4 ,geol4 ,soc4 ,lond41 vol4 #ai1 #ahfc1 pp4 #bce-bei4 ,glacial ,lake ,agassiz3-- ,,w>r5 ,,upham4 ,! ,glacial ,lake ,agassiz4 ,mon4 #be1 ,u4 ,s4 ,geol4 ,surv41 pp4 #feh1 pls4 #ch4 ,f4 ,w4 ,,s>deson4 ,beg9n+ & ,recession ( ,/4 ,an?ony's ,falls1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ai1 #aijh1 pp4 #bi-cf4 ,glacial lakes 9 ! ,/4 ,lawr5ce valley3-- ,,*amb]l9 ,,& ,,salisbury4 ,geology1 vol4 #c1 pp4 #cid-dje4 ,,frank ,,lev]ett4 ,outl9e ( ! ,hi/ory ( ! ,great ,lakes 7,presid5tial ,address71 #ab? ,rept4 ,mi*4 ,acad4 ,sci41 #aiaj1 pp4 #ai-db4 ,! ,plei/oc5e ,features & ,deposits ( ! ,*icago ,area4 ,*icago1 #ahig1 pp4 #hf1 pls4 #h 7,*icago ,outlet74 ,h4 ,l4 ,,fair*ild4 ,glacial ,lakes 9 ,we/]n ,new ,york1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #f1 #ahie1 pp4 #cec-cgd1 pls4 #ah-bc2 ,glacial ,wat]s 9 ,c5tral ,new ,york4 ,bull4 #abg1 ,n4 ,y4 ,/ate ,mus41 #aiji1 pp4 #ff1 pls4 #db1 & maps 9 cov]4 ,e>ly lakes 9 ! ,erie bas93-- ,,frank ,,lev]ett4 ,on ! ,correlation ( ,mora9es ) ,rais$ ,bea*es ( ,lake ,erie1 ,am4 ,j\r4 ,sci4 7#c71 vol4 #dc1 #ahib1 pp4 #bha-cja4 ,f4 ,b4 ,,taylor4 ,! ,great ,ice ,dams ( ,lakes ,maumee1 ,:ittlesey1 & ,w>r51 ,am4 ,geol41 vol4 #bd1 #ahii1 pp4 #f-ch1 pls4 #b-c2 ,relation ( ,lake ,:ittlesey to ! ,arkona ,bea*es1 #g? ,rept4 ,mi*4 ,acad4 ,sci41 #aije1 pp4 #cj-cf4 ,,frank ,,lev]ett4 ,! ,ann ,arbor ,folio1 ,folio ,no4 #aee1 ,u4 ,s4 ,geol4 ,surv41 #aijh1 pp4 #aj-ab4 ,,*apt] ,,xxiv ,,! ,,uptilt ,,( ,,! ,,l& ,,at ,,! ,,close ,,( ,,! ,,ice ,,age ,! response ( ! e>?'s %ell to its ice mantle4--,!re is n[ good reason to believe t ! e>?'s out] %ell makes a response by oscillations ( level due to ! load+ by ice1 on ! "o h&1 & to ! removal ( ?is burd5 ^u ! o!r4 ,we "k1 at lea/1 t bo? 9 nor!rn ,europe & 9 ,nor? ,am]ica areas :i* h und]gone depression dur+ & elevation aft] ! ice age1 correspond closely to ! regions :i* 7 ice cov]$4 ,:]ev] 9 ^! regions !re 0 high relief be=e ! adv5t ( ! ice1 riv] valleys 7 dr[n$ at ! l& m>g9s & 7 also g\g$ out into tr\ghs ?r\gh erosion by ! outlet tongues ^u ! m>g9 ( ! ice %eet4 ,su* furr[$ & half-subm]g$ valleys h a *>act]i/ic ,u-%ap$ section1 s t _! walls rise precipit\sly f ! sea4 ,f _! typical occurr5ce 9 ,sc&9avian c\ntries ! "n fjord has be5 appli$ to !m4 ,x is n[ no less cle> t ! removal ( ! ice blanket br\ght f ! e>? a relatively quick response 9 uplift1 :i* began be=e ! ice front _h retir$ across ! pres5t int]national b\nd>y ( ! ,unit$ ,/ates1 & t ?is uplift cont9u$ until ! f9al disappe>ance ( ! ice4 ,a f> sl[] elevation ( a some:at diff]5t nature has cont9u$1 ev5 to ! pres5t day4 ,x is obvi\s t at ! "t ( _! =mation all %ore l9es ref]able to ! "w ( waves mu/ h be5 horizontal1 & h5ce any v>iations f a p]fect level :i* !y reveal to-day mu/ indicate t a tilt+ movem5t ( ! gr\nd has occurr$ s9ce ! wat]s dep>t$ f _! bas9s4 ,we h ?us provid$ = u 9 ! positions ( ^! anci5t wat] planes1 p>ticul>ly because ( _! wide ext5t1 a complete record ! ref9em5t ( :i* is n easily ov]/at$4 ,int]pret+ ?is record1 we f9d t x 0 ! uptilt ( ! l& to ! nor?w>d :i* br\ght ! glacial lake hi/ory to an end & inaugurat$ ! pres5t sy/em ( ,/4 ,lawr5ce dra9age4 ,! outlet ( ! ,nipiss+ ,great ,lakes is to-day m ?an a hundr$ feet above ! level ( ! outlet at ,port ,huron1 :]e ! upp] lakes are n[ dis*>g+ _! wat]s1 & ?is diff]5ce 9 level c only be ascrib$ to an upw>d tilt+ ( ! l& s9ce ! late/ ( ! glacial lake /ages4 ,! ab&on$ /r&s z !y appe> to-day4--,! travel] by /eam] ^u ! upp] lakes1 z he comes )9 view ( ea* rocky headl&1 may note h[ ! pr(ile aga9/ ! horizon is not*$ by a s]ies ( /eps or t]races 7,fig4 #cfh71 & if he has foll[$ ! discussion 9 previ\s *apt]s1 he w suspect t ^! t]races m>k ! n[ ab&on$ %ore l9es :i* h come to _! pres5t position ?r\gh a s]ies ( uplifts ( ! gr\nd accompani$ by e>?quake %ocks4 ,z 8 /eam] skirts ! %ore he may *ance to note a cave )9 ! rock cliff :i* repres5ts ! n[ elevat$ sea-ar* ( an anci5t %ore4 ,illu/ration3 ,,fig4 #cfh4--,! not*$ rock headl& ( ,boy] ,bluff betwe5 ,gre5 ,bay & ,lake ,mi*igan 7aft] ,gold?wait74 ,disemb>k+ f ! /eam] & travel+ inl& at any po9t :]e ! %ores are high1 ! travel] is c]ta9 to come ^u /ill m conv9c+ pro(s ( ! anci5t /r&s2 p]haps 9 a /orm bea* ( ! unmi/akable 8%+le01 half buri$ ?\gh x may be "u dunes ( newly drift$ s&1 or possibly at high] levels ! highway has be5 cut ?r\gh a %+le b>ri] z fre% & unmi/akable z ?\gh =m$ ^u ! pres5t %ore4 ,sometimes x is ! rock cliff & t]race1 at o!r times b>ri] ridges ( %+le1 or1 aga91 x is ! slop+ cliff & t]race cut 9 ! drift deposits2 b ( :atev] sort1 if /udi$ ) prop] reg>d to ! topography ( ! di/rict1 ! evid5ce is cle> & unmi/akable4 ,! records ( uplift ab\t ,mack9ac ,isl&4--,n[h]e are ! records ( ! rec5t uplift ( ! lake region m easily read ?an ab\t ,mack9ac ,isl& 9 ! /raits connect+ ,lake ,mi*igan ) ,lake ,huron4 ,approa*+ ! isl& by /eam] f ,/4 ,ignace1 its pr(ile ^u ! horizon is wor?y ( rem>k 7,fig4 #cfi74 ,f a c5tral cre/ brok5 by m9or irregul>ities & b\nd$ on all sides by a cliff1 ! isl& pr(ile slopes g5tly away to a /ill l[] cliff1 bel[ :i* is ano!r t]race4 ,illu/ration3 ,,fig4 #cfi4--,view ( ,mack9ac ,isl& f ! direction ( ,/4 ,ignace4 ,! irregul> c5tral portion is ! only "p ( ! isl& t 0 n subm]g$ 9 ,lake ,algonqu94 ,! t]race at its base is ! old %ore l9e ( ,lake ,algonqu91 & ! l[] t]race ! /r& ( ,lake ,nipiss+ 7aft] a photograph by ,taylor74 ,illu/ration3 ,,fig4 #cgj4--,! 8,sug> ,loaf01 a /ack ne> ! %ore ( ,lake ,algonqu91 z x is se5 f ! obs]vatory ^u ,mack9ac ,isl& 7aft] a photograph by ,taylor74 ,:5 we h rea*$ ! isl& & h climb$ to ! summit1 we !re f9d ! surface :i* is *>act]i/ic ( erosion by runn+ wat]1 :]eas at l[] levels are f\nd ! =ms c>v$ or mold$ by ! action ( waves4 ,?is c5tral 8isl&01 sup]impos$ ^u ! l>g] isl&1 is all t rose above ,lake ,algonqu91 ! e>lie/ ( ! glacial lakes 9 ?is nor!rn di/rict2 & z we look out f ! obs]vatory ^u ! summit1 x is easy to call up a picture ( ! c\ntry :5 ! lake /ood at ! base ( ?is highe/ cliff4 ,to ! nor?w>d "o sees ! 8,sug> ,loaf0 rise out ( a sea ( foliage1 z x =m]ly did f ! wat]s ( ,lake ,algonqu9 7,fig4 #cgj74 ,x is a huge /ack ne> ! =m] isl& %ore4 ,if we turn n[ to ! s\?w>d & direct our gaze t[>d ! ,=t1 we enc\nt] a v]itable succession ( bea* ridges =m$ ( %+le & rang$ l a s]ies ( waves )9 ! cle>$ space ( ! 8,%ort ,t>get ,range0 7,fig4 #cga74 ,^! ridges m>k ea* a /age )9 a s]ies ( successive uplifts :i* h br\ght ! isl& to its pres5t height4 ,illu/ration3 ,,fig4 #cga4--,view f ! obs]vatory ^u ,mack9ac ,isl& across ! 8,%ort ,t>get ,range0 t[>d ! ,=t4 ,bea* ridges appe> 9 succession )9 ! cle>$ space 7aft] a photograph by ,rossit]74 ,illu/ration3 ,,fig4 #cgb4--,not*$ /ack ( ! ,nipiss+ ,great ,lakes at ,/4 ,ignace 7aft] a photograph by ,taylor74 ,illu/ration3 ,,fig4 #cgc4--,s]ies ( diagrams to illu/rate ! evolution ( ideas conc]n+ ! uplift ( ! lake region s9ce ! ice age4 ,a1 simple nor!rly up-cant+ 7,gilb]t73 ,b1 nor!rly accel]ation ( ! up-cant+ 7,sp5c] & ,upham72 ,c1 nor!rly 8fea!r+ out0 ( bea*es 7,sp5c] & ,upham72 ,d1 h+e1 l9e ( up-cant+ f\nd )9 ! lake region 7,lev]ett72 ,e1 multiple & nor?w>dly migrat+ h+e l9es ( up-cant+ 7,hobbs74 ,if n[ we desc5d f our position & visit ! 8battlefield01 we f9d !re a great ridge ( level cre/1 beh9d :i* ! ,briti% =ce 0 /ation$ 9 its def5se ( ! isl& 9 #ahab4 ,ne> by 9 ! woods is ,pulpit ,rock1 a /rik+ly p]fect /ack ( ! ,nipiss+ ,lake4 ,across ! /raits at ,/4 ,ignace is an ev5 f9] example ( ! not*$ /ack 7,fig4 #cgb74 ,o!r less prom95t bea*es1 b all lat] ?an ! ,nipiss+ ,lakes1 int]v5e betwe5 ?is level & ! pres5t %ore to m>k ! /ages 9 ! cont9u$ uplift ( ! l&4 ,! pres5t incl9ations ( ! uplift$ /r&s4--,x is n en\gh t we %\ld h recogniz$ ! m>ks ( =m] %ores n[ at consid]able elevations above ! exi/+ lakes2 if we are to "k ! nature ( ! uplift1 we mu/ prep>e accurate maps bas$ ^u measurem5ts by precise level+ at _m localities4 ,su* me?ods are1 h[ev]1 ( comp>atively rec5t application 9 ?is field2 &1 z 9 ! inve/igation ( s _m o!r problems1 ! e>li] obs]vations 7 l>gely ( ! nature ( reconnaissances ) ! elevation ( bea*es e/imat$ by comp>atively crude me?ods only4 ,! evolution ( ideas conc]n+ ! uptilt has1 !re=e1 be5 a gradual "o4 ,illu/ration3 ,,fig4 #cgd4--,map ( ! ,great ,lakes region to %[ isobases & h+e l9es ( uptilt4 a1 isobase ( ! ,*icago outlet2 b1 ma9 h+e l9e ( ! ,lake ,:ittlesey bea* 7,lev]ett72 b#a1 h+e l9e ( ! ,lake ,w>r5 bea* 7,taylor72 c1 isobase ( ! ,port ,huron outlet2 d1 ma9 h+e l9e ( highe/ ,algonqu9 bea* 7,gold?wait72 e1 f1 g1 h1 additional h+e l9es ( ,algonqu9 bea*es 9 ,door ,c\nty p59sula 7,hobbs72 l1 isobase ( ! ,lake ,sup]ior outlet = ! ,algonqu9 bea*es 7,lev]ett73 m1 isobase ( ! same outlet = ! ,nipiss+ bea*es 7,lev]ett74 ,x 0 e>ly obs]v$ t ! bea*es correspond+ to a giv5 lake /age 7 high] to ! nor?w>d & nor!a/w>d1 & ! natural conclusion f ?is 0 t ! e>?'s cru/ _h "h be5 cant$ l a trap door 7,fig4 #cgc1 ,a74 ,z we are to see1 ?is b half-correct assumption has l$ to a /rik+ prophecy relat+ to future *anges )9 ! lake region :i* we n[ "k to be )\t w>rant 9 ! facts4 ,lat] x 0 le>n$ t ! uptilt ( ! lake bea*es is mu* accel]at$ to ! nor?w>d 7,fig4 #cgc1 ,b71 & t new bea*es make _! appe>ance f b5ea? o!rs z we proce$ 9 ?is direction--!re is a 8fea!r+ out0 ( bea*es to ! nor?w>d 7,fig4 #cgc1 ,c74 ,! h+e l9es ( uptilt4--,/ill lat] 9 ! /udy ( ! region1 x 0 le>n$ t ! axis or fulcrum ab\t :i* ! region has be5 uptilt$1 in/ead ( ly+ to ! s\?w>d ( ! lake di/rict1 z _h be5 assum$ by ,gilb]t1 lay )9 ! region & ab\t halfway up ! bas9 ( ,lake ,mi*igan 7,fig4 #cgc1 ,d1 & ,fig4 #cgd74 ,simil>ly1 9 ! uptilt :i* foll[$ ! ice retreat 9 nor!rn ,europe a def9ite h+e l9e ( movem5t has be5 discov]$4 ,la/ly1 x has be5 %[n1 z a result ( ! use ( precise level+ me?ods1 t n "o b sev]al h+e l9es ( movem5t lie )9 ! region1 & t ! sep>ate sections into :i* !y divide ! area are ea* 9 turn *>act]iz$ by increas$ up-cant z we proce$ to ! nor?w>d 7,fig4 #cgc1 ,e & ,fig4 #cgd74 ,illu/ration3 ,,fig4 #cge4--,s]ies ( ideali/ic diagrams to indicate ! nature ( ! quick recov]y ( ! cru/ by uplift 9 blocks unload$ ( ! ice 9 succession4 ,a fur!r & sl[] uptilt1 add$ aft] ! completion ( ! fir/ movem5t1 is br\ght out 9 ! la/ diagram 7b74 ,! bea*es ( ,lake ,maumee1 ! e>lie/ ( ! s]ies ( lakes )9 ! ,huron-,erie lobe & )9 ! extreme s\!rn portion ( ! ,great ,lakes area1 %[ only ! slighte/ possible nor!rly uptilt1 & ! well-m>k$ h+e l9e disclos$ 9 ! ,:ittlesey bea* is evid5ce t ! ela/ic recoil1 z x 71 f ! weight ( ! mantl+ glaci] did n beg9 until aft] ! dra9+ ( ,lake ,:ittlesey4 ,! det]m9ation by ,taylor t !re is a simil> initial h+e l9e 9 ! ,w>r5 bea*--t ?is /r& beg9s its uptilt "s fifte5 miles f>!r nor!a/ ?an does ! ,:ittlesey bea*--is "o ( ! greate/ importance 9 obta9+ a correct idea ( ! rec5t uplift2 = x %[s t ! dra9+ ( ,lake ,:ittlesey 0 foll[$ by a p]iod ( quick uplift & seismic activity1 t ! /age ( ,lake ,w>r5 0 "o ( comp>ative /ability ( ! l&1 &1 la/ly1 t ! dra9+ ( ,lake ,w>r5 0 foll[$ by a second p]iod ( rapid uplift & e>?quake di/urbance4 ,! /rongly m>k$ h+e l9es1 additional to ! initial "o indicat$ = ! ,algonqu9 bea*es 9 ! pr(iles by ,gold?wait f ! we/ %ore ( ,lake ,mi*igan1 :5 consid]$ 9 ! light ( ?is nor!a/]ly migration ( ! /ill e>li] h+e l9e 9 ! s\!rn di/rict1 are be/ expla9$ ?r\gh ! assumption ( a succession ( quick recov]ies ( ! cru/ by uplift1 sep>at$ by p]iods ( relative /ability1 & br\ght on by ! removal 9 turn ( ! ice burd5 f successive blocks ( ! %ell :i* are sep>at$ by ! sev]al h+e l9es 7,fig4 #cge74 ,! elaborate /udy ( erosion 9 ! outlet ( ,lake ,agassiz _h indicat$ id5tical int]ruptions 9 ! up-cant+ process = t bas94 ,future consequ5ces ( ! cont9u$ uptilt )9 ! lake region4--,"o ( ! mo/ di/+ui%$ ( ,am]ican geologi/s1 ,dr4 ,g4 ,k4 ,gilb]t1 9 ord] to det]m9e :e!r ! uptilt reveal$ by cant$ bea* l9es is /ill 9 progress1 c>ri$ out an elaborate /udy ^u ! gauge records pres]v$ at ! v>i\s gaug+ /ations ab\t ! ,great ,lakes4 ,^u ! basis ( ^! /udies1 he conclud$ t ! uplift cont9ues1 t ! axes ( equal uplift 7isobases7 take _! c\rse ab\t fifte5 degrees nor? ( we/1 s t ! l9es ( greate/ uptilt %\ld be p]p5dicul> to ?is direction1 or fifte5 degrees ea/ ( nor?4 ,he fur!r believ$ t ! bas9 0 und]go+ an up-cant 9 ! simple mann] ( a trap door1 ! h+e ( :i* lay to ! s\?w>d ( ,*icago1 & ! /udy ( ! gauge records l$ him to believe t 8! rate ( *ange is su* t ! two ends ( a l9e "o hundr$ miles long & ly+ 9 a s\?-s\?we/ direction are relatively displac$ f\r t5?s ( a foot 9 "o hundr$ ye>s40 ,gilb]t's prophecy ( a future outlet ( ! ,great ,lakes to ! ,mississippi4--,! natural rock sill1 ov] :i* ! wat]s ( ,lake ,*icago once fl[$ to ! ,mississippi1 is to-day b eight feet above ! common mean level ( ,lakes ,mi*igan & ,huron1 & if ! tilt+ ( ! lake region 7 to cont9ue ^u ,gilb]t's assumption ( a cant+ plane ) ! h+e ( ! movem5t to ! s\? ( ,*icago1 a "t mu/ come :5 ! 8,*icago outlet0 w aga9 come into use & ! lakes once m dra9 to ! ,mississippi & ! ,gulf4 ,^u ! basis ( 8 measurem5ts1 ,gilb]t v5tur$ ! prophecy t ! fir/ high-wat] dis*>ge into ! ,mississippi %\ld occur 9 f five hundr$ to six hundr$ ye>s1 & = cont9u\s dis*>ge 9 fifte5 hundr$ ye>s4 ,9 tw5ty-five hundr$ ye>s ,niag>a ,falls %\ld at l[ wat] /ages be dry f ?is cause1 & 9 ?irty-five hundr$ ye>s x %\ld h become ext9ct4 ,?is prophecy1 emanat+ f a high sci5tific au?ority & relat+ to *anges ( su* pr(\nd economic & comm]cial importance1 has be5 (t5 quot$ & has tak5 a firm hold ^u ! popul> imag9ation4 ,obvi\sly1 x dep5ds ^u ! n[ explod$ !ory t ! lake bas9 has be5 cant$ z a plane & t ! axis ( uptilt lies some:]e to ! s\?w>d ( ! lake region1 or1 9 any ev5t1 to ! s\?w>d ( ! pres5t ,port ,huron outlet4 ,we "k to-day t in/ead ( be+ uni=mly di/ribut$ ov] ! entire lake region1 ! uptilt+ goes on at a mu* high] rate )9 ! nor!rn areas1 & t s9ce ! e>ly /age ( ,lake ,:ittlesey ! h+e l9e ( uplift has be5 /eadily migrat+ nor?w>d ) ! retreat ( ! ice & is n[ well to ! nor?w>d ( ! pres5t outlet4 ,!re is1 !re=e1 no kn[n uptilt ( ! di/rict :i* sep>ates ! pres5t f ! =m] ,*icago outlet1 & !re is no app>5t natural cause :i* %\ld result 9 ! reoccupation ( ! old outlet to ! ,mississippi4 ,! prophecy mu/ be reg>d$ z "o t has be5 outgr[n ) ! progress ( sci5ce4 ,geological evid5ces ( cont9u$ uplift4--,x has rec5tly be5 claim$1 on ! basis ( a rexam9ation ( ,gilb]t's /udy ( ! lake gauge records1 t 8 me?ods are op5 to s]i\s criticism & t 9 reality ! figures af=d no evid5ce ( cont9u$ uplift ( ! region4 ,h[ev] ?is may be1 !re are n lack+ geological evid5ces :i* d n admit ( d\bt1 & ^! are 9 a /rik+ way confirmatory ( ! late/ conclusions ^u ! mann] ( ! rec5t uplift4 ,if our conclusions h be5 correct1 ! sev]al lake bas9s %\ld n[ be behav+ 9 diff]5t ways z reg>ds ! *anges ^u _! %ores4 ,if x is true t ! l9es ( greate/ uptilt run nor?-nor!a/]ly1 !re %\ld be1 speak+ broadly1 a 8spill+ ov]0 ( wat]s ^u ! s\?-s\?we/]ly %ores & a lay+ b>e ( ! nor?-nor!a/]ly %ore t]races ( ! bas9s4 ,?is %\ld1 h[ev]1 be true only ( bas9s ^: outlets are to ! nor!a/w>d ( ! exi/+ ma9 h+e l9e ( uptilt4 ,lake ,huron1 hav+ its outlet at ! s\!rn m>g9 ( its bas91 %\ld n h its wat]s encroa*+ ^u ! s\!rn %ore1 = ! simple reason t any cont9u$ uptilt ( ! bas9 c only h ! effect ( p\r+ m wat] ?r\gh ! outlet4 ,lake ,mi*igan & ,sag9aw ,bay1 :i* are arms ( ! ,huron bas91 ought1 h[ev]1 to become flood$ ^u _! s\!rn %ores1 7 x n t ! h+e l9e ( uptilt to-day lies to ! nor?w>d ( ! outlet at ,port ,huron1 &1 fur!r1 t ! two connect+ *annels /ill h _! b$s l[] ?an ! sill ( ! outlet *annel4 ,n[ ! evid5ce goes to %[ t no encroa*m5t ( wat]s is occurr+ ^u ! ,*icago %ore ( ,lake ,mi*igan1 & al?\gh ! %ores ( ,sag9aw ,bay are s excessively flat z to reveal slight *anges ( level by l>ge migrations ( ! /r&1 yet ! anci5t me&] po/s fix$ by ! e>ly surveys are /ill f\nd ne> ! wat]'s edge4 ,dr[n+ ( s\?we/]n %ores ( ,lakes ,sup]ior & ,erie4--,)9 ! bas9s occupi$ by ,lakes ,sup]ior & ,erie1 a :olly diff]5t condition is f\nd4 ,9 ea* case ! outlet is f\nd to ! nor!a/w>d 7,fig4 #cgd1 p4 #cde71 & ! nor?we/]ly tr5d ( ! isobases f ^! outlets is responsible = a cont9u$ elevation f uptilt ( ! outlets ) ref]5ce to ! we/]n & s\!rn %ores4 ,9 consequ5ce1 ! wat]s are encroa*+ ^u ^! %ores1 & riv]s :i* !re ent] ! lake are dr[n$ at _! m\?s1 ) ! =mation ( e/u>ies4 ,^u ,lake ,sup]ior ^! *anges are v m>k$ ne> ,dulu? & p>ticul>ly 9 ! ,/4 ,l\is ,riv]1 )9 :i*1 s9ce ! e>ly treaty ) ! ,indians1 c]ta9 rapids h disappe>$ & subm]g$ trunks ( trees are n[ f\nd 9 ! *annel ( ! riv]4 ,z f> ea/ z ,ontonagon ess5tially ! same conditions are f\nd4 ,^u ! %ores )9 ! ,porcup9e ,m\nta9 di/rict1 ! wat]s are cle>ly ris+4 ,"h old c$> trees may be se51 9 "s cases dead b /ill upright & /&+ 9 f six to eight in*es ( wat] a numb] ( feet out f ! pres5t %ore1 :ile o!rs ne> ! %ore1 b ^u ! l& & /ill liv+1 are wa%$ by ! waves1 & los+ _! l[] b>k 9 consequ5ce4 ,an old road along ! %ore has _h to be ab&on$ because ( ! encroa*+ wat]4 ,^u ! opposite or nor!a/]n %ore ( ! lake1 on ! o!r h&1 ! l& is ev]y:]e ris+ out ( ! wat]1 & ! waves are n[ build+ /orm bea*es well out ^u ! wave-cut t]race4 ,"h ! /reams1 in/ead ( =m+ e/u>ies by dr[n+1 drop d[n 9 rapids to ! level ( ! lake4 ,illu/ration3 ,,fig4 #cgf4--,portion ( ! ,inn] ,s&usky ,bay1 to af=d a comp>ison ( ! %ore l9e ( #ahbj ) t ( to-day 7aft] ,moseley74 ,at ! s\?we/]n m>g9 ( ,lake ,erie !re is ev]y:]e evid5ce ( a rapid encroa*m5t by ! wat]4 ,9 ! caves ( ,s\? ,bass ,isl& /alactites1 :i* mu/ obvi\sly h =m$ above ! lake level1 are n[ p]man5tly subm]g$4 ,x is1 h[ev]1 ab\t ,s&usky ,bay ^u ! s\?we/ %ore t ! mo/ /rik+ obs]vations h be5 made4 ,moseley has collect$ hi/orical records ( ! kill+ ( =e/ trees ?r\gh a subm]g5ce :i* 0 ! result ( an advance ( ! wat] ^u ! %ores4 ,x seems to be prov5 f 8 /udies t ! wat] is n[ ris+ 9 ,s&usky ,bay at a rate ( ab\t #b4ad feet p] c5tury4 ,9 ,fig4 #cgf !re is a comp>ison ( ! %ores ( ! inn] bay sep>at$ by an int]val ( ab\t n9ety ye>s4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxiv ,uptilt 9 bas9 ( ,lake ,agassiz3-- ,,w>r5 ,,upham4 ,! ,glacial ,lake ,agassiz1 ,mon4 #be1 ,u4 ,s4 ,geol4 ,surv41 pp4 #dgd-ebb4 ,uptilt 9 ,laur5tian ,bas93-- ,g4 ,k4 ,,gilb]t4 ,rec5t ,e>? ,movem5t 9 ! ,great ,lakes ,region1 #ah? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahih1 ,pt4 ii1 pp4 #eie-fdg4 ,j4 ,w4 ,,sp5c]4 ,de=mation ( ! ,algonqu9 ,bea*1 etc41 ,am4 ,j\r4 ,sci4 7#c71 vol4 #da1 #ahia1 pp4 #ad-af4 ,f4 ,b4 ,,taylor4 ,! ,highe/ ,old ,%ore ,l9e ( ,mack9ac ,isl&1 ,am4 ,j\r4 ,sci4 7#c71 vol4 #dc1 #ahib1 pp4 #baj-bah4 ,a4 ,c4 ,,lawson4 ,sket* ( ! ,coa/al ,topography ( ! ,nor? ,side ( ,lake ,sup]ior1 ) ref]5ce to ! ab&on$ /r&s1 etc41 #bj? ,ann4 ,rept4 ,geol4 & ,nat4 ,hi/4 ,surv4 ,m9n41 #ahic1 pp4 #aha-bhi1 pls4 #g-ab4 ,j4 ,b4 ,,woodwor?4 ,anci5t ,wat] ,levels ( ! ,*ampla9 & ,hudson ,valleys1 ,bull4 #hd1 ,n4,y4 ,/ate ,mus41 #aije1 pp4 #bfe1 pls4 #bh4 ,e4 ,l4 ,,moseley4 ,=mation ( ,s&usky ,bay & ,c$> ,po9t1 ,proc4 ,ohio ,/ate ,acad4 ,sci41 vol4 #d1 #aije1 ,pt4 v1 pp4 #agi-bch4 ,f4 ,e4 ,,wright4 ,rept4 ,geol4 ,surv4 ,mi*4 = #aijc1 #aije1 p4 #cg4 ,j4 ,w4 ,,gold?wait4 ,! ,ab&on$ ,%ore ,l9es ( ,ea/]n ,wiscons91 ,bull4 #ag1 ,wis4 ,geol4 & ,nat4 ,hi/4 ,surv41 #aijg1 pp4 #acd1 pls4 #cg2 ,a ,recon/ruction ( ,wat] ,planes ( ! ,ext9ct ,glacial ,lakes 9 ! ,lake ,mi*igan ,bas91 ,j\r4 ,geol41 vol4 #af1 #aijh1 pp4 #dei-dgf2 ,isobases ( ! ,algonqu9 & ,iroquois ,bea*es & _! ,significance1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #ba1 #aiaj1 pp4 #bbg-bdh1 pl4 #e2 ,an ,in/rum5tal ,survey ( ! ,%ore ,l9es ( ! ,ext9ct ,lakes ,algonqu9 & ,nipiss+ 9 ,s\?we/]n ,ont>io1 ,mem4 #aj1 ,dept4 ( ,m9es1 ,canada1 #aiaj1 pp4 #eg1 pls4 #d4 ,,william ,h4 ,,hobbs4 ,! ,late ,glacial & ,po/-glacial ,uplift ( ! ,mi*igan ,bas91 ,pub4 #e1 ,mi*4 ,geol4 & ,biol4 ,surv41 #aiaa1 pp4 #fh1 pls4 #b4 ,,lawr5ce ,,m>t94 ,po/-glacial ,modifications 9 & ,ar\nd ! ,great ,lakes1 ,mon4 #eb1 ,u4 ,s4 ,geol4 ,surv41 #aiaa1 pp4 #dee-dei4 ,uptilt 9 nor!rn ,europe3-- ,g4 ,,de ,,ge]4 ,quat]n>y ,*anges ( ,level 9 ,sc&9avia1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #c1 #ahib1 pp4 #fe-fh1 pl4 #b4 ,h4 ,,mun!4 ,/udies 9 ! ,late ,quat]n>y ,hi/ory ( ,s\!rn ,sw$51 pap] ,no4 #be1 ,livret ,guide1 ,cong4 ,gol4 ,int]n41 #aiaj1 pp4 #if1 _m plates & maps4 ,,*apt] ,,xxv ,,niag>a ,,falls ,a ,,clock ,,( ,,rec5t ,,geological ,,"t ,features 9 & ab\t ! ,niag>a gorge4--,a /rik+ example ( ^? p]man5t alt]ations ( dra9age :i* h result$ f ! pres5ce ( ! late cont95tal glaci] 9 ,nor? ,am]ica is to be f\nd 9 ! ,niag>a gorge betwe5 ,lakes ,erie & ,ont>io4 ,) ! aid ( bor+s _m ( ! n[ buri$ *annels ( ! region h be5 foll[$ out1 & 9 a lat] p>agraph we %all ref] to "s ( ! /rong] l9es ( ! e>li] dra9age sy/em4 ,be=e und]tak+ ! /udy ( ,niag>a hi/ory1 x is ess5tial t "o become some:at famili> ) ! pres5t topography 9 & ab\t ! ,niag>a gorge4 ,bel[ ! pres5t cat>act ! riv] fl[s ?r\gh a deep gorge = ab\t sev5 miles be=e issu+ at ! ,lewi/on ,esc>pm5t 7,fig4 #cha1 p4 #cee74 ,?is gorge has be5 cut 9 b$s ( rock s$im5ts :i* dip at a g5tle angle s\?w>d t[>d ,lake ,erie4 ,! capp+ ( ! rock s]ies is a compact & relatively resi/ant lime/one :i* is kn[n z ! ,niag>a lime/one1 b5ea? :i* !re are alt]nat+ b$s ( %ale ) ?9n] lime/one & s&/one4 ,! pla9 =m$ by ! upp] surface ( ! lime/one capp+ t]m9ates 9 ! ,lewi/on ,esc>pm5t1 :i* is transv]se to ! direction ( ! gorge & sev5 miles di/ant bel[ ! ,falls4 ,! dep? ( ! gorge v>ies m>k$ly1 ! above-wat] portion be+ repres5t$ at ! upp] end by ! height ( ! cat>act1 "o hundr$ & sixty-five feet1 :ile at its l[] end ne> ,lewi/on x is twice t am\nt4 ,halfway d[n ! gorge a %>p turn is made at an angle ( m ?an n9ety degrees1 & ! up/ream arm is ext5d$ to =m a bas9 :i* conta9s ! fam\s :irlpool4 ,?is visible ext5sion ( ! upp] gorge is cont9u$ 9 a buri$ *annel1 ! ,/4 ,davids ,gorge1 :i* ext5ds to ! esc>pm5t1 broad5+ z x does s 9 ! =m ( a trumpet4 ,! mat]ials :i* fill ?is e>li] *annel are notably co>se glacial deposits 7,fig4 #chi74 ,illu/ration3 ,,fig4 #cgg4--;,ideal cross section ( ! ,niag>a gorge to %[ ! m>g9al t]race4 ,directly above ! :irlpool ! ,niag>a gorge is fir/ contract$1 b almo/ imm$iately swells out into ! =m ( a sausage1 :i* "u ! "n ( ! ,eddy ,bas9 ext5ds to ! con/rict$ *annel occupi$ by ! ,:irlpool ,rapids4 ,?is ,gorge ( ! ,:irlpool ,rapids ext5ds to & a little above ! railroad bridges1 :]e x aga9 sudd5ly wid5s & deep5s & ) surpris+ly uni=m cross section n[ cont9ues z f> z ! cat>act4 ,?is upp]mo/ section is kn[n z ! ,upp] ,great ,gorge4 ,ab\t a mile bel[ ! :irlpool is t rem>kable projection into ! gorge f ! ,canadian wall :i* is kn[n z ,w9t]gre5 ,flats1 bel[ :i* & ne>] ! riv] are ,fo/]s ,flats4 ,almo/ ?r\gh\t its entire l5g? ! ,niag>a gorge is bord]$ on ei!r side by a n>r[ & g5tly incurv+ t]race erod$ bel[ ! g5]al level ( ! pla9 & meet+ ! gorge 9 a %>p angle 7,fig4 #cgg74 ,! features imm$iately ab\t ! cat>act %[ t ! ,falls are to-day 9 a condition :i*1 s f> z we "k1 has occurr$ b once be=e 9 _! entire hi/ory--! wat]s ( ! riv] are divid$ unequally by an isl&1 & = ?is reason1 z we %all see1 ! cat>act ent]s ov] ! side wall ( ! gorge in/ead ( at its end 7,fig4 #cha71 al?\gh ! turn+ ( ! *annel f ?is cause is comb9$ ) a b5d ( ! riv]4 ,illu/ration3 ,,fig4 #cgh4--,view ( ! b$ ( ! ,niag>a ,riv] above ! cat>act1 :]e wat] has be5 dra9$ (f 9 in/all+ a p[] plant4 ,"s sep>at$ blocks ( lime/one are /ill 9 place 7aft] ,j4 ,w4 ,sp5c]74 ,! drill+ ( ! gorge4--,!re appe> to be two important processes :i* are responsible = ! recession ( ! ,falls1 ! rate ( :i* is det]m9$ l>gely by ! resi/ance ( ! lime/one capp+ & ! t5acity ( ! loos] %ale b5ea? x4 ,"o ( ! erod+ processes op]ates f bel[ & und]m9es ! cap until ! unsupport$ cornice falls 9 blocks to ! bottom ( ! gorge2 ! o!r makes its attack directly f above1 select+ = ! purpose ! l9es ( jo9t+ ( ! rock :i* x wid5s by solution & corrasion until ! includ$ blocks are 9 s f> sep>at$ t !y are torn out & g ov] ! br9k ( ! ,falls 7,fig4 #cgh74 ,?is process ( ov]head attack 9 ! p[]ful curr5ts j above a cat>act is ev5 bett] illu/rat$ by ! ,falls ( ,/4 ,an?ony ne> ,m9neapolis1 :i* h _h a simil> hi/ory ( recession to t ( ! ,niag>a ,falls 7,fig4 #cgi74 ,illu/ration3 ,,fig4 #cgi4--;,falls ( ,/4 ,an?ony1 look+ we/w>d f ,h5nep9 ,isl& 9 #ahea 7aft] ,n4 ,h4 ,w9*ell1 dagu]reotype by ,hessl] ( ,*icago74 ,! blocks ( ! capp+ lime/one at ,niag>a ,falls are to "s ext5t fix$ 9 size by ! jo9t planes pres5t 9 !m1 & z !y fall to ! bottom ( ! gorge1 !y promote or ret>d ! fur!r recession ( ! ,falls accord+ z !y c or _c be mov$ ab\t by ! *urn+ curr5ts b5ea? ! cat>act4 ,( ! ret>d+ effect !re is an illu/ration 9 ! accumulation ( ! blocks bel[ ! ,am]ican & ! int]m$iate ,luna ,falls 7plate #bc ,a71 :i* ! weak] curr5ts ^u ! ,am]ican side f9d too heavy to h&le4 ,illu/ration3 ,,fig4 #chj4--;,ideal section to %[ ! nature ( ! drill+ process b5ea? ! cat>act4 ,illu/ration3 ,,fig4 #cha4--,plan & section ( ! ,niag>a gorge1 %[+ h[ 9 ea* section ! dep? is proportional to ! wid?1 except 9 ! l[e/ section :]e subsequ5t riv] action ( ! normal type has modifi$ ! b$ ( ! *annel 7plan aft] ,taylor & section aft] ,gilb]t74 ,! ,canadian ,fall1 ) its mu* great] p[]1 is an example ( ! promotion ( recession ?r\gh ! *urn+ ab\t ( ! blocks at ! base ( ! cat>act4 ,we h "h to d ) a *urn drill :i* bores its way into ! bottom ( ! gorge ) increas+ radius ( rot>y motion ) ea* increase 9 volume ( ! fall+ wat]4 ,"u ?is rot>y *urn+ ! s(t %ales are torn out ne> ! bottom & 9 succession ! h>d] lay]s above until ! capp+ is rea*$ 7,fig4 #chj74 ,! conditions appe> n[ to be su* t ! effective "w is l>gely conc5trat$1 z x usually has be51 ne> ! middle ( ! *annel2 & s ! gorge rec$es ) a m>g9 ( ! e>li] riv] b$ rema9+ z a t]race on ei!r side & ext5d+ to ! =m] riv] bank 7,fig4 #cgg74 ,z mu/ h be5 not$1 "o peculi>ity ( ! op]ation ( ! *urn drill b5ea? ! cat>act is t ! dep? ( ! gorge w be> a direct proportion to its wid?1 & if ! volume ( wat] has v>i$ dur+ ! process ( recession1 ^! *anges 9 volume w be regi/]$ 9 ! wid? & also 9 ! dep? ( t section ( ! gorge :i* 0 drill$ at ! "t--! cross section ( ! gorge at any place is proportional to ! volume ( ! wat] fall+ 9 ! cat>act :i* produc$ x1 modifi$1 h[ev]1 by ! compet5cy to h&le ! jo9t blocks ( def9ite size 7,fig4 #cha74 ,illu/ration3 ,,fig4 #chb4--;,comp>ison ( a sket* ( ! ,canadian ,fall made ) ! aid ( a cam]a lucida 9 #ahbg ) a photograph tak5 f ! same view po9t 9 #ahie 7aft] ,gilb]t74 ,! pres5t rate ( recession4--,!re are v>i\s sket*es1 m or less accurate1 made 9 ! e>ly "p ( ! n9ete5? c5tury1 & f ! lat] p]iod !re are dagu]reotypes1 photographs1 & maps1 :i* ref] especially to ! ,canadian ,fall2 & :i*1 tak5 toge!r1 r5d] possible a comp>ison ( ! e>li] ) ! lat] br9ks4 ,by comp>+ ! e>lie/ ) ! rec5t1 views x is se5 at a glance t ! ,falls are rec$+1 & at a q appreciable rate 7,fig4 #chb74 ,a c>eful comp>ison ( ! maps made 9 #ahdb1 #ahge1 #ahhf1 #ahij1 & #aije ( ! br9k ( ! ,canadian ,fall 7,fig4 #chc7 indicates t = ! p]iod cov]$ ! rate ( recession has be5 ab\t five feet p] ye>1 & simil> /udies made ( ! ,am]ican ,fall %[ t x has be5 rec$+ at ! rate ( only ?ree in*es p] ye>1 or "o tw5tie? ! rate ( ! recession ( ! ,canadian ,fall4 ,illu/ration3 ,,fig4 #chc4--,map to %[ ! recession ( ! br9k ( ! ,canadian ,fall1 bas$ ^u maps ( diff]5t dates 7aft] ,gilb]t74 ,future ext9ction ( ! ,am]ican ,fall4--,x is because ( ?is _m times m rapid recession ( ! ,canadian ,fall t ! ,niag>a cat>act1 in/ead ( ly+ a?w>t ! gorge1 ent]s x f its side4 ,! ,canadian ,fall is ?us 9 reality sw++ ab\t ! ,am]ican1 & ! "t c already be r\ghly e/imat$ :5 ?is m effective drill+ tool w h br\ght ab\t a capture1 s to speak1 ( ! ,am]ican ,fall ?r\gh ! cutt+ (f ( its wat] supply4 ,x w !n be dra9$ & left lit]ally 8high & dry01 an endur+ witness to ! geological effect ( an isl& 9 mak+ an unequal division ( ! wat]s = ! "w ( two cat>acts4 ,z already po9t$ out1 ! ineffici5cy ( ! ,am]ican ,fall z an erod+ ag5t is amply atte/$ by ! wall ( blocks already appe>+ above ! wat] bel[ x4 ,! t\ri/ :o a ?\s& ye>s h5ce pays a visit to ! ,niag>a cat>act1 provid$ ! wat] fl[ is all[$ to rema9 z x has be51 w f9d above ?is ramp>t ( blocks a b>e cliff 9 "p und]m9$1 & surm\nt$ by a ne>ly flat table surface :i* is cut (f f ! exi/+ cat>act by a high] section ( ! gorge 7,fig4 #chd74 ,x is q likely t ?is table w furni% ! mo/ satisfactory viewpo9t ( ! future cat>act ( t date4 ,illu/ration3 ,,fig4 #chd4--;,comp>ison ( ! pres5t ) ! future falls4 ,! captur$ ,canadian ,fall at ,w9t]gre5 ,flats4--,:at we h pr$ict$ = ! future ( ! pres5t ,am]ican ,fall w be ! bett] und]/ood f ! /udy ( a monum5t to e>li] capture made long be=e ! upp] section ( ! gorge _h be5 cut or ! :irlpool _h come into exi/5ce4 ,! tables 7 !n turn$1 = x 0 a fall ^u ! ,canadian side ( ! gorge t 0 captur$ by "o ^u ! ,am]ican4 ,! locality is kn[n z ,w9t]gre5 ,flats1 or sometimes z ,fo/]s ,flats2 ?\gh ! fir/ "n prop]ly applies to a high] surface ne> ! br9k ( ! gorge1 & ,fo/]s ,flats to a l[] pla9 ne> ! level ( ! riv] 7see ,fig4 #cha1 p4 #cee74 ,! peculi> topographic features at ?is locality are well br\ght out 9 ,gilb]t's bird's-eye view ( ! locality 7,fig4 #che72 9 fact1 9 "s respects bett] ?an !y appe> to ! t\ri/ ^u ! gr\nd1 = ! reason t ! ab&on$ *annel & ! ,flats on ! site ( ! s9ce und]m9$ isl& are bo? heavily =e/$ & s n easy to include 9 a s+le view4 ,= "o :o has /udi$ ! exi/+ cat>act ?is e>ly monum5t is full ( mean+4 ,/&+1 z "o may1 ^u ! v br9k ( ! =m] cat>act1 x is easy to call up 9 imag9ation ! gr&eur ( ! e>li] surr\nd+s & to he> ! ?und] ( ! fall+ wat]4 ,a p>ticul>ly vivid t\* is add$ :51 9 digg+ ov] ! s& ab\t ! great blocks ( fall5 lime/one und]nea? ! br9k1 "o comes ^u ! %ells ( an animal /ill liv+ 9 ! ,niag>a ,riv]1 ?\gh only 9 ! cont9ual spray b5ea? ! cat>act4 ,illu/ration3 ,,fig4 #che4--;,bird's-eye view ( ! captur$ ,canadian ,fall at ,w9t]gre5 ,flats1 %[+ ! section ( ! riv] b$ above ! cliff & ! blocks ( fall5 ,niag>a lime/one /rewn ov] ! ab&on$ *annel bel[ 7aft] ,gilb]t74 ,! ,:irlpool ,bas9 excavat$ f ! ,/4 ,davids ,gorge4--,x has already be5 po9t$ out t a rock *annel n[ fill$ ) glacial deposits ext5ds f ! ,:irlpool ,bas9 to ! edge ( ! esc>pm5t at ,/4 ,davids 7,fig4 #chi1 p4 #cfc74 ,9 plan ?is buri$ gorge has a trumpet =m1 be+ m ?an two miles wide at its m\? & n>r[+ to ! wid? ( ! upp] gorge be=e x has rea*$ ! ,:irlpool4 ,ne> ! ,:irlpool x has be5 9 "p excavat$ by ,b[man ,creek1 ?us reveal+ walls t are well glaciat$4 ,diff]5t op9ions h be5 express$ conc]n+ ! orig9 ( ?is *annel1 "o be+ t x is ! c\rse ei!r ( a preglacial riv] or "o incis$ betwe5 consecutive glacial invasions2 & ano!r t x is a cat>act gorge drill$ out betwe5 glacial invasions aft] ! mann] ( ! lat] ,niag>a gorge4 ,9 ei!r case its cont\rs h be5 mu* modifi$ by ! lat] glaci] or glaci]s1 ^: "w ( plan+1 poli%+1 & wid5+ is reveal$ 9 ! expos$ surfaces2 & x is n improbable t a cat>act has rec$$ along ! c\rse ( an e>li] riv] valley4 ,z we %all see1 !re are facts :i* po9t r cle>ly to an e>li] cat>act :i* end$ its life imm$iately above ! pres5t ,:irlpool4 ,:5 ! lat] ,niag>a cat>act _h rec$$ to ne> ! upp] end ( ! ,cove section1 or ne> ! pres5t ,:irlpool1 ! fall+ wat] mu/ h be5 sep>at$ f ?is old] *annel & its fill+ ( till deposits by only a ?9 wall ( rock1 & ?is mu/ h be5 con/antly weak5$ z its ?ickness 0 fur!r r$uc$4 ,:5 ?is weak5$ dam at la/ gave way1 x mu/ h produc$ a debacle gr& 9 ! extreme4 ,x is h>dly to be conceiv$ t ! 8wa%\t0 ( ! anci5t *annel to =m ! ,:irlpool ,bas9 c\ld h occupi$ m ?an a small fraction ( a day1 ?\gh x is highly probable t ! brok5 rock p>tition bel[ ! ,:irlpool 0 n imm$iately remov$ entire4 ,! m&ible-l t]m9ation ( ! ,eddy ,bas9 imm$iately above ! ,:irlpool has l$ ,taylor to believe t ! cat>act quickly re/abli%$ itself at ?is po9t ^u ! la/ site ( ! ext9ct ,/4 ,davids cat>act4 ,if r$uc$ 9 p[] = a %ort int]val1 z a result ( ! ob/ructions /ill rema9+ 9 ! lately brok5 dam bel[ ! ,:irlpool1 ! rem>kable n>r[+ ( ! gorge at ?is po9t w\ld be suffici5tly acc\nt$ =4 ,be+ compell$ to turn ?r\gh m ?an a "r angle aft] x ent]s ! ,:irlpool ,bas91 ! swift curr5t ( ! ,niag>a ,riv] is =c$ to d\ble ^u itself aga9/ ! opposite bank & dive bel[ ! incom+ curr5t be=e em]g+ into ! ,cove section bel[ ! ,:irlpool 7,fig4 #chf74 ,illu/ration3 ,,fig4 #chf4--,map ( ! ,:irlpool ,bas91 %[+ ! rock side walls l ^? ( ! ,niag>a ,gorge1 & ! drift bank :i* =ms ! nor?we/ wall 7aft] ,gilb]t74 ,9 te>+ out ! loose deposits :i* _h fill$ ?is "p ( ! buri$ ,/4 ,davids ,gorge1 _m b[ld]s ( great size 7 left :i* slid d[n ! slope & 9 "t produc$ an armor ab\t ! loos] deposits b5ea?1 s z to protect !m & prev5t cont9u$ excavation4 ,?us x is f\nd t ! subm]g$ nor?we/]n wall ( ! bas9 is %ea!d ) b[ld]s l>ge en\gh to reta9 _! positions & s /op a natural process ( plac] outwa%+ ^u a gigantic scale 7,fig4 #chf74 ,! %ap+ ( ! ,lewi/on ,esc>pm5t4--,to und]/& ! =mation ( ! ,lewi/on ,esc>pm5t cut 9 ! h>d ,niag>a lime/one1 x is necess>y to consid] ! geology ( a mu* l>g] area--t ( ! ,great ,lakes region z a :ole4 ,to ! nor? ( ! ,lakes 9 ,canada is f\nd a mo/ anci5t cont95t :i* 0 9 exi/5ce :5 all ! area to ! s\?w>d lay bel[ ! wat]s ( ! ocean4 ,9 a p]iod /ill v _m times z long ago z ! ev5ts we h "u discussion1 !re 7 laid d[n (f ! %ore ( ?is oldl& a s]ies ( unconsolidat$ deposits :i*1 h>d5$ 9 ! c\rse ( "t1 & elevat$1 are n[ repres5t$ by ! %ales1 s&/one1 & lime/one :i* we f9d1 "o above ! o!r1 9 ! ,niag>a gorge 9 ! ord] 9 :i* !y 7 laid d[n ^u ! ocean floor4 ,! =mations repres5t$ 9 ! gorge are b a "p ( ! entire s]ies1 = o!r high] memb]s are repres5t$ by rocks ab\t ,lake ,erie & ev5 f>!r to ! s\?w>d4 ,^! /rata1 hav+ be5 =m$ ^u an outw>d slop+ sea floor1 _h a small initial dip to ! s\?w>d1 & ?is has be5 probably increas$ by subsequ5t uptilt1 includ+ ! late/ :i* we h s rec5tly _h "u discussion4 ,at ! pres5t "t ! b$s dip s\?w>d by an angle ( less ?an f\r degrees1 or ab\t ?irty-five feet 9 ea* mile4 ,illu/ration3 ,,fig4 #chg4--,map to %[ ! cue/as :i* h play$ s important a "p 9 fix+ ! b\nd>ies ( ! ,lake bas9s1 & also ! pr9cipal preglacial riv]s by :i* !y h be5 tr5*$ 7bas$ ^u a map by ,grabau74 ,:5 ! elevation ( ! l& 9 ! vic9ity ( ?is %ore _h caus$ a recession ( ! wat]s1 !re 0 =m$ a coa/al pla9 on ! bord]s ( ! oldl& l t :i* is n[ f\nd ^u our ,atlantic bord] betwe5 ! ,appala*ians & ! sea 7,fig4 #bgb1 p4 #bdf74 ,! riv]s f ! oldl& cut _! way 9 n>r[ tr5*es across ! newl&1 & because ( ! h>d] lime/one =mations1 _! tribut>ies gradually became div]t$ f _! e>li] c\rses until !y ent]$ ! trunk /ream ne>ly at "r angles & produc$ ! type ( dra9age network :i* is call$ 8trellis dra9age40 ,x is *>act]i/ic ( ?is dra9age t few tribut>ies ( ! second ord] w fl[ up ! natural slope ( ! b$s1 b on ! contr>y ^! natural slopes are foll[$ 9 ! s(t] rock ne>ly at "r angles aga9 to ! tribut>ies ( ! fir/ ord] ( magnitude 7,fig4 #chg74 ,?us are produc$ a s]ies ( m or less p>allel esc>pm5ts =m$ 9 ! h>d] rock & hav+ at _! base a l[l& :i* rises gradually 9 ! direction ( ! oldl& until a new esc>pm5t is rea*$ 9 ! next l[] ( ! h>d =mations4 ,su* flat-topp$ upl&s 9 s]ies ) int]m$iate l[l&s & sep>at$ by %>p esc>pm5ts are kn[n z cue/as 7see p4 #bdf71 & ! ,lewi/on ,esc>pm5t limits t =m$ 9 ,niag>a lime/one 7,figs4 #chg & #chh74 ,illu/ration3 ,,fig4 #chh4--;,bird's-eye view ( ! cue/as s\? ( ,lakes ,ont>io & ,erie 7aft] ,gilb]t74 ,episodes ( ,niag>a's hi/ory & _! correlation ) ^? ( ! ,glacial ,lakes4--,( ! e>ly episodes ( ,niag>a's hi/ory1 our k is n z p]fect z we c\ld desire1 b ! lat] ev5ts are fully & tru/wor?ily record$4 ,! bir? ( ! ,falls is to be dat$ at ! "t :5 ! ice front _h "h fir/ retir$ into :at is n[ ,canadian t]ritory1 ?us = ! fir/ "t all[+ ! wat]s f ! ,erie bas9 to dis*>ge ov] ! ,lewi/on ,esc>pm5t into ! bas9 ( ! newly =m$ ,lake ,iroquois 7,fig4 #cfd1 p4 #ccd74 ,s9ce ! level ( ,lake ,iroquois 0 f> above t ( ! pres5t ,lake ,ont>io1 ! new-born cat>act 0 n ! equival5t 9 height ( ! esc>pm5t to-day4 ,! ,iroquois wat]s !n ba!d all ! l[] portion ( ! esc>pm5t1 s t ! foot ( ! ,fall 0 ^u ! bord]s ( ! ,lake4 ,9 ord] to int]pret ! hi/ory ( ! ,niag>a gorge1 we mu/ rememb] t ! effective drill+ ( ?is gorge 0 9 ea* /age dep5d5t ma9ly ^u ! volume ( wat] dis*>g$ f ,lake ,erie1 a l>ge dis*>ge be+ record$ by a *annel drill$ bo? wide & deep1 :ile t produc$ by ! dis*>ge ( a small] volume 0 correspond+ly n>r[ & %all[4 ,to-day ! gorges ( l>ge cross section h1 moreov]1 a relatively placid surface1 :]eas ?r\gh ! con/rict$ sections ! wat] ( ! riv] is unable to pass )\t fir/ rais+ its level at ! upp] end & "u ! head ?us produc$ ru%+ ?r\gh "u an increas$ velocity4 ,! be/ illu/ration ( su* a con/rict$ section is ! ,gorge ( ! ,:irlpool ,rapids4 ,illu/ration3 ,,fig4 #chi4--,sket* map ( ! great] portion ( ! ,niag>a ,gorge to %[ ! *anges 9 cross section 9 _! relations to ,niag>a hi/ory 7bas$ ^u a map by ,taylor74 ,our read+ ( ! hi/ory %\ld beg9 at ! site ( ! pres5t cat>act1 s9ce ! records ( lat] ev5ts are s mu* ! m complete & legible1 & x %\ld ev] be our plan to proce$ f ! cle>ly writt5 pages to ^? half effac$ & illegible4 ,z we h le>n$1 ! mo/ abrupt *ange 9 ! cross section ( ! gorge is f\nd a little above ! railroad bridges1 :]e ! ,upp] ,great ,gorge is jo9$ to ! ,gorge ( ! ,:irlpool ,rapids 7,fig4 #chi74 ,9 view ( ! rem>kably uni=m cross section ( ! ,upp] ,great ,gorge1 !re is no reason to d\bt t x has be5 drill$ ?r\gh\t "u ess5tially ! same volume ( wat]1 & t its l[] limit m>ks ! position ( ! =m] cat>act :5 ! wat]s f ! upp] lakes 7 transf]r$ f ! 8,nor? ,bay ,outlet0 into ! pres5t or 8,port ,huron ,outlet0 & ,lake ,erie4 ,z ! upp] limit ( ! ,gorge ( ! ,:irlpool ,rapids ?us corresponds to ! clos+ ( ! 8,nor? ,bay ,outlet0 & ! ext9ction ( ! ,nipiss+ ,great ,lakes1 s its l[] limit d\btless corresponds to ! op5+ ( t outlet & ! t]m9ation ( ! prec$+ ,algonqu9 /age2 = 9 ! /age ( ! ,nipiss+ lakes ! wat] ( ! upp] lakes1 z we h le>n$1 rea*$ ! ocean ?r\gh ! nor!rn outlet4 ,mr4 ,frank ,taylor1 :o has giv5 mu* /udy to ! problem ( ,niag>an hi/ory1 believes t ! ,middle ,great ,gorge1 compris+ ! ,eddy ,bas9 & ! ,cove section1 repres5ts ! gorge drill+ :i* occurr$ dur+ ! lat] /age ( ,lake ,algonqu9 aft] ! 8,tr5t ,outlet0 _h be5 clos$ & ! wat]s ( ! upp] lakes _h be5 turn$ into ! ,erie ,bas94 ,summ>iz+1 !n1 ! episodes ( ! lake & ! gorge hi/ory are to be correlat$ z foll[s3-- ,,glacial ,,lake ,,niag>a ,,gorge ,e>ly ,lakes ,iroquois & ,algonqu94 ,drill+ ( ! gorge f ! ,lewi/on ,esc>pm5t to ! ,cove section above ! ,w9t]gre5 ,flats4 ,lat] ,lakes ,iroquois & ,algonqu9 ,drill+ ( ,middle ,great ,gorge4 ) upp] lakes dis*>g+ into ,erie bas94 ,nipiss+ ,great ,lakes ) ! ,drill+ ( ! n>r[ ,gorge ( upp] lake wat]s div]t$ f ! ,:irlpool ,rapids4 ,lake ,erie4 ,rec5t ,/4 ,lawr5ce dra9age ,drill+ ( ,upp] ,great ,gorge to s9ce ! wat]s ( ! upp] lakes ! pres5t cat>act4 7 dis*>g$ into ,lake ,erie ?r\gh occupation ( ! ,port ,huron ,outlet4 ,"t measures ( ! ,niag>a clock4--,9 primitive civilizations "t has sometimes be5 measur$ by ! lapse necess>y to accompli% a c]ta9 task1 su*1 = example1 z walk+ ! di/ance betwe5 two po9ts2 & ! natural clock ( ,niag>a has be5 ( ?is type4 ,b m5 possess diff]5ces 9 /r5g? & spe$1 & ! same man is at "s times m vigor\s ?an at o!rs1 & s does n "w at a uni=m rate4 ,! cat>act ( ,niag>a1 *>g$ ) ! p5t-up en]gy ( ! wat]s ( all ! ,great ,lakes1 c ru% its "w z x is cle>ly unable to d at times :5 ! great] "p ( ?is en]gy has be5 div]t$4 ,units ( di/ance measur$ along ! gorge are !re=e too unreliable = our use1 ) ! unique exception ( ! /ret* f ! railroad bridges to ! site ( ! pres5t cat>act1 )9 :i* /ret* ! gorge cross sections are s ne>ly uni=m z to indicate an approximation to cont9u$ application ( uni=m en]gy4 ,?is en]gy we may actually measure 9 ! exi/+ cat>act1 & s fix ^u a unit ( "t t c be translat$ into ye>s4 ,9 ord] to secure ! normal rate ( recession ( ?is ,upp] ,great ,gorge1 we %\ld add to ! volume ( wat] 9 ! ,canadian ,fall t n[ pass+ ov] ! ,am]ican2 & = ! reason t ! blocks :i* fall f ! cat>act cornice & are ! tools ( ! drill+ in/rum5t approximate to a def9ite size fix$ by _! jo9t planes1 ! effect ( ?is add$ en]gy x is n easy to e/imate4 ,we may be sure1 h[ev]1 t ! drill+ action w\ld be some:at increas$ by ! junction ( ! two ,falls1 & ?us are assur$ t ! av]age rate ( recession )9 ! ,upp] ,great ,gorge has be5 some:at 9 excess ( ! five feet p] ye> det]m9$ by ,gilb]t = ! pres5t ,canadian ,fall4 ,! ,upp] ,great ,gorge is ab\t two miles 9 l5g?1 & its beg9n+ may ?us be dat$ ne> ! dawn+ ( ! ,*ri/ian ,era4 ,! ,:irlpool ,gorge 0 cut :5 ! ice vacat$ ! ,nor? ,bay ,outlet 9 ,canada1 & /ill lay z a broad mantle ov] all nor!a/]n ,canada4 ,= ! e>li] gorge & lake /ages1 ! "t e/imates are h>dly m ?an guesses1 & we ne$ n n[ conc]n ourselves ) !m4 ,! horologe ( late glacial "t 9 ,sc&9avia4--,a glacial timepiece ( some:at diff]5t con/ruction & ( great] ref9em5t has be5 made use ( 9 ,sc&9avia to d]ive ! 8geo*ronology ( ! la/ #ab1jjj ye>s40 ,in/ead ( retreat+ ov] ! l& & imp\nd+ ! dra9age z x did s1 ! late/ cont95tal glaci] ( ,sc&9avia end$ bel[ sea level1 & z x retir$1 its great subglacial riv] laid d[n a giant esk] kn[n z ! ,/ockholm ,os1 :i* 0 bord]$ by a delta & fr+$ on ei!r side by wat]-laid mora9es ( ! block type4 ,^! recessional mora9es are ^u ! av]age less ?an #ajjj feet ap>t1 & are believ$ to h ea* be5 =m$ 9 a s+le season4 ,! delta deposits :i* surr\nd ! esk] are ( ?9-b&$ clay1 & z an additional upp]mo/ b& is f\nd outside e mora9e1 ^! b&s are also believ$ to repres5t ea* ! delta deposit ( a s+le ye>4 ,9 /udies ext5d+ ov] _m ye>s1 ,b>on de ,ge]1 ) ! aid ( a l>ge body ( /ud5t help]s1 has succe$$ 9 complet+ a c\nt ( mora9es & clay lay]s1 & s 9 det]m9+ ! "t to be #ab1jjj ye>s s9ce ! ice front ( ! late/ cont95tal glaci] lay across s\!rn ,sw$54 ,! f]tility ( conception & ! ?or\ghness ( execution ( ?is epo*-mak+ inve/igation recomm5d its conclusion to ! sci5tific read]4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxv ,g4 ,k4 ,,gilb]t4 ,niag>a ,falls & _! ,hi/ory1 ,nat4 ,geogr4 ,soc4 ,mon41 vol4 #a1 ,no4 #g1 #ahie1 pp4 #bjc-bcf4 ,f4 ,b4 ,,taylor4 ,orig9 ( ! ,gorge ( ! ,:irlpool ,rapids at ,niag>a1 ,bull4 ,geol4 ,soc4 ,am41 vol4 #i1 #ahih1 pp4 #ei-hd4 ,a4 ,w4 ,,grabau4 ,guide to ! ,geology & ,paleontology ( ,niag>a ,falls & ,vic9ity1 ,bull4 ,n4 ,y4 ,/ate ,mus41 vol4 #i1 ,no4 #de1 #aija1 pp4 #a-he1 pls4 #a-aa4 ,j4 ,w4 ,,sp5c]4 ,! ,falls ( ,niag>a1 etc4 ,dept4 ( ,m9es1 ,geol4 ,surv4 ,bran*1 ,canada1 #aijg1 pp4 #dij1 pls4 #dc4 ,g4 ,k4 ,,gilb]t4 ,rate ( ,recession ( ,niag>a ,falls1 etc4 ,bull4 #cjf1 ,u4 ,s4 ,geol4 ,surv41 #aijg1 pp4 #ca1 pls4 #aa4 ,g4 ,,de ,,ge]4 ,quat]n>y ,sea ,bottoms ( ,we/]n ,sw$54 ,pap] #bc1 ,livret ,guide ,cong4 ,gol4 ,int]n41 #aiaj1 pp4 #eg1 pls4 #c4 ,,*apt] ,,xxvi ,,l& ,,sculpture ,,by ,,m\nta9 ,,glaci]s ,contra/$ sculptur+ ( cont95tal & m\nta9 glaci]s4--,9 discuss+ 9 a previ\s *apt] ! rock pavem5t lately uncov]$ by ! ,gre5l& glaci]1 we le>n$ t ?is surface _h be5 l[]$ by ! processes ( pluck+ & abrasion1 ! comb9$ effect ( :i* is always to r$uce ! irregul>ities ( ! surface1 s(t5 its outl9es1 & f %>ply project+ masses to develop r\nd$ %\ld]s ( rock--ro*es m\tonnes4 ,?\gh ! same processes act 9 mu* ! same mann] b5ea? m\nta9 glaci]s1 ?\gh "h ^u all p>ts ( ! b$1 !y are1 9 ! e>li] /ages at lea/1 subord9at$ to a ?ird process m important ?an ! two act+ toge!r4 ,sculpture by m\nta9 glaci]s1 in/ead ( r$uc+ surface irregul>ities & s(t5+ outl9es1 increases ! acc5t ( ! relief & produces ! mo/ %>ply rugg$ topography t is kn[n4 ,9 ne>ly all places :]e ,alp9i/s resort = difficult rock climb+1 m\nta9 glaci]s are to be se51 or ! evid5ce = _! =m] pres5ce may be read 9 unmi/akable *>act]s4 ,w9d di/ribution ( ! sn[ :i* falls 9 m\nta9s4--,until q rec5tly /ud5ts ( glaciation h conc]n$ !mselves b little ) ! "w ( ! w9d 9 lift+ & r$i/ribut+ ! sn[ aft] x has fall54 ,we h already se5 t1 = ! cont95tal glaci]s1 w9d appe>s to be ! *ief transport+ ag5t1 if we except ! m>g9al lobes :]e glaci] fl[ assumes l>ge importance4 ,9 ! case ( m\nta9 glaci]s1 also1 we are to f9d t = ! e>li] /ages p>ticul>ly w9d is ( ! fir/ importance z a r$i/ribut+ ag5t4 ,9 ! high] levels sn[ is swept up f ! gr\nd by all high w9ds1 & does n f9d a re/+ place until x is dropp$ b5ea? an eddy 9 "s irregul>ity ( ! surface2 & if ! inh]it$ surface be relatively smoo?1 ?is w be f\nd 9 mo/ cases ^u ! lee ( ! m\nta9 cre/4 ,9 normal cases at lea/ ! inh]it$ irregul>ities ( ! high] zones ( m\nta9 upl& are ! g5tle depressions :i* develop at ! heads ( /reams4 ,^! become1 !n1 ! sites ( sn[drifts t are augm5t$ 9 size f ye> to ye>1 ?\gh at fir/ !y melt away 9 ! late summ]4 ,illu/ration3 ,,fig4 #cij4--,sn[drift holl[+ its b$ by nivation & build+ a delta 7at ! left74 ,quadrant ,m\nta91 ,yell[/one ,national ,p>k4 ,! ni*es :i* =m on sn[drift sites4--,:]ev] a drift is =m$1 a process is set 9 op]ation1 ! effect ( :i* is to holl[ out & l[] ! gr\nd b5ea? x1 a process :i* has be5 call$ nivation4 ,! drift %[n 9 ,fig4 #cij 0 photograph$ 9 late summ] at an elevation ( "s #ijjj feet 9 ! ,yell[/one ,national ,p>k4 ,! v g5tly slop+ surface surr\nd+ ! drift is cov]$ ) grass1 b )9 a zone a few feet 9 wid? on ! bord]s ( ! drift no grass is gr[+1 & 9 its place is f\nd a f9e br[n soil :i* is fa/ becom+ ! prey ( ! mov+ wat] d]iv$ by melt+ ( ! drift4 ,?is is expla9$ by ! wat] p]meat+ ! crevices ( ! rock & be+ r5t by ! nightly freez+4 ,f>!r f ! drift ! gr\nd is dry1 & no su* action is possible4 ,) ea* succe$+ spr+ ! augm5t$ drift z x melts c>ries all f9ely comm9ut$ rock mat]ial d[n slopes b5ea? ! sn[ to em]ge at ! l[e/ m>g9 & be !re deposit$ 9 ! =m ( a delta4 ,by ! op]ation ( ?is process ( nivation ! high] p>ts ( ! drift site are l[]$ z deposition goes on ^u ! l[]4 ,! comb9$ effect is ?us to produce a ni*e or fa9tly et*$ amphi!at] ^u ! slope ( ! m\nta9 7,fig4 #cia74 ,illu/ration3 ,,fig4 #cia4--;,amphi!at] =m$ on a drift site 9 nor!rn ,lapl& 7aft] a photograph by ,g4 von ,zahn74 ,! augm5t$ sn[drift moves d[n ! valley--bir? ( ! glaci]4--,9 /ill l[] air temp]atures ! drifts enl>ge ) ea* succe$+ ye> until !y endure ?r\gh\t ! summ] season4 ,f ?is /age on1 an increm5t ( sn[ is left f ea* succe$+ season4 ,no long] entirely wa/$ by melt+1 ! "t soon comes :5 ! upp] sn[ lay]s w by _! weight compress ! l[] into ice1 & ! mass w beg9 to creep d[n ! slope along ! c\rse ( ! inh]it$ valley4 ,! enl>g$ sn[drift :i* fe$s ?is ice /ream is call$ ! nv or firn4 ,aga9/ ! slop+ cliff :i* _h be5 %ap$ by nivation at ! upp] m>g9 ( ! sn[drift1 t sn[ :i* is n ( suffici5t dep? to beg9 a movem5t t[>ds ! valley sep>ates f ! mov+ portion1 op5+ z x does s a cleft or crevasse p>allel to ! wall4 ,?is crack 9 ! sn[ is call$ by its ,g]man "n ,b]gs*rund or ,r&spalte1 & may p]haps be ref]r$ to z ! m>g9al crevasse 7,fig4 #cib74 ,illu/ration3 ,,fig4 #cib4--,! m>g9al crevasse or ,b]gs*rund on ! highe/ m>g9 ( a glaci] 7aft] ,gilb]t74 ,! excavation ( ! glacial amphi!at] or cirque4--,x has be5 f\nd t ! m>g9al crevasse plays a mo/ important rle 9 ! sculpture ( m\nta9s by glaci]s1 = ! great amphi!at] :i* is ev]y:]e ! collect+ bas9 = ! n\ri%m5t ( m\nta9 glaci]s is n an inh]it$ feature1 b ! h&iwork ( ! ice itself4 ,?is 0 ! discov]y ( ,mr4 ,w4 ,d4 ,johnson1 an ,am]ican topograph] & geologi/1 :o1 9 ord] to solve ! problem ( ! amphi!at] all[$ himself to be l[]$ into su* a crevasse ^u ! ,m\nt ,lyell glaci] ( ! ,si]ra ,nevadas 9 ,cali=nia4 ,illu/ration3 ,,fig4 #cic4--,ni*es & cirques 9 ! same vic9ity 9 ! ,bighorn ,m\nta9s ( ,wyom+4 ,a1 ,a1 unmodifi$ valleys2 ,b1 ,b1 ni*es on drift sites2 ,c1 ,c1 cirques on small glaci] sites 7aft] map by ,f4 ,e4 ,ma!s1 ,u4 ,s4 ,g4 ,s474 ,let d[n a di/ance ( a hundr$ & fifty feet1 he rea*$ ! bottom ( ! crack1 & 9 a drizzl+ ra9 ( ?aw wat] /ood ^u a floor compos$ ( rock masses 9 "p dislodg$ f a wall :i* ext5d$ "s tw5ty feet upw>ds ^u ! cliff side ( ! crevasse4 ,x 0 evid5t t ! w>m air ( ! day produc$ ! ?aw wat] :i* 0 con/antly dripp+ & :i* fill$ e crack & cranny ( ! rock surface4 ,) ! s9k+ ( ! sun bel[ ! peaks ! sudd5 *ill1 s *>act]i/ic ( ! end ( ! day 9 high m\nta9s1 causes ?is wat] to freeze & ?us r5d ! rock along its planes ( jo9t+4 ,broad & ?9 plates ( ice1 loos5$ by melt+ at ! walls1 c\ld be extract$ f ! crevices ( ! rock z mute witnesses to ! p[]ful /resses develop$ by ?is mo/ vigor\s ( wea!r+ processes4 ,illu/ration3 ,,fig4 #cid4--,subord9ate small cirques 9 ! amphi!at] on ! we/ face ( ! ,wannehorn above ! ,great ,alets* ,glaci] ( ,switz]l&4 ,9 %ort1 ! rock wall above ! glaci]1 :i* 9 its initial /age 0 ! upp] wall ( ! ni*e holl[$ b5ea? ! sn[drift1 is fir/ /eep5$ & lat] cont9ually bo? recess$ & deep5$ by an int5sive fro/ r5d+ :i* is 9 op]ation at ! base ( ! m>g9al crevasse4 ,! same process does n g on z rapidly above ! surface ( ! nv = ! reason t ! necess>y wett+ ( ! rock surface does n !re s g5]ally result f ! daily summ] ?aw4 ,at ! bottom ( ! m>g9al crevasse alone is ?is condition fully realiz$4 ,int5sive fro/ action :]e ! rock is wet ) ?aw wat] daily is ?us a fundam5tal cause1 bo? ( ! holl[+ ( ! e>ly drift site to =m ! ni*e1 & ( ! lat] enl>gem5t ( ?is ni*e into an amphi!at] or cirque :5 ! drift has be5 trans=m$ into ! nv ( a glaci]4 ,inasmu* z ! crevasse =ms :]e ! sn[ & ice pull away f ! rock t[>d ! middle ( ! depression1 ! cirque wall 9 its e>ly /age has ! outl9e ( a semicircle4 ,9 ! ,bighorn ,m\nta9s ( ,wyom+1 all /ages1 f ! unmodifi$ valley heads to ! full-=m$ cirque1 may be se5 ne> "o ano!r 7,fig4 #cic74 ,x w be not$ t :]ev] a glaci] has =m$1 z indicat$ by ! cirque1 !re is a s]ies ( lakes :i* h develop$ 9 ! valley bel[ 7see p4 #dab74 ,illu/ration3 ,,fig4 #cie4--8;,biscuit cutt+0 effect ( glacial sculpture 9 ! ,u9ta ,m\nta9s ( ,wyom+ 7aft] ,atwood74 ,illu/ration3 ,,fig4 #cif4--,two int]sect+ inv]t$ cones repres5t+ glacial cirques ( diff]5t sizes1 to %[ t _! int]section is ! arc ( a hyp]bola1 ! curve to :i* ! col approximates4 ,life hi/ory ( ! cirque4--,9 its e>lie/ /age ! cirque is m or less uni=mly suppli$ ) sn[ f all sides1 & s x enl>ges by recession 9 a mann] to reta9 its e>ly semicircul> outl9e4 ,9 a lat] /age a l>g] proportion ( ! sn[ rea*es ! cirque at its sides s t its fur!r enl>gem5t causes x to broad5 & to flatt5 some:at t "p ( its outl9e :i* repres5ts ! head ( ! valley 7,fig4 #chi1 p4 #cfd74 ,z ! t]ritory ( ! upl& is /ill fur!r inve/$ by ! cirques1 _! n\ri%m5t becomes /ill m irregul>1 & ! circul> outl9e gives place to a scallop$ bord]1 z ! amphi!at] becomes diff]5tiat$ into subord9ate small] cirques1 ea* ( :i* corresponds to a scallop ( ! outl9e 7,fig4 #cih & ,fig4 #cid74 ,groov$ & frett$ upl&s4--,! p>tial inve/m5t by cirques ( a m\nta9 upl& yields a type ( topography q unlike t produc$ by any o!r geological process4 ,! irregul>ly connect$ remnants ( ! inh]it$ upl& resemble no?+ s mu* z a lay] ( d\gh f :i* biscuits h be5 cut 7,fig4 #cie74 ,! surface z a :ole1 furr[$ z x is bel[ ! cirques1 may be describ$ z a groov$ upl& 7plate #ai ,a74 ,a fur!r cont9uation ( ! process removes all traces ( ! e>li] upl&1 = ! cirques int]sect f opposite sides & ?us yield palisades ( %>p rock p9nacles :i* rise on precipit\s walls f a t]rac$ floor4 ,?is ultimate product ( cirque sculpture by glaci]s is call$ a frett$ upl& 7plate #ah ,a & #ai ,b74 ,,plate #ah4 ,illu/ration3 ,a4 ,frett$ upl& ( ! ,alps se5 f ! summit ( ,m\nt ,blanc4 ,illu/ration3 ,b4 ,model ( ! ,malasp9a ,glaci] & ! frett$ upl& above x 7aft] model by ,l4 ,m>t974 ,,plate #ai4 ,illu/ration3 ,a4 ,cont\r map ( a groov$ upl&1 ,bighorn ,m\nta9s1 ,wyom+ 7,u4 ,s4 ,geol4 ,survey74 ,illu/ration3 ,b4 ,cont\r map ( a frett$ upl&1 ,philipsburg ,quadrangle1 ,montana 7,u4 ,s4 ,geol4 ,survey74 ,! features c>v$ above ! glaci]4--,! ranges ( p9nacles c>v$ out by m\nta9 glaci]s h become kn[n by v>i\s names ( =eign d]ivation1 su* z arte1 grat1 aiguille m\nta9s1 8files ( g5d>mes01 etc4 ,!y may1 p]haps1 be be/ ref]r$ to z comb ridges1 & accord+ to _! position !y are diff]5tiat$ into ma9 & lat]al comb ridges1 z w be cle> f ! second map ( plate #ai4 ,illu/ration3 ,,fig4 #cig4--;,a col %ap$ l a hyp]bola betwe5 ,m\nt ,sir ,donald & ,yogo ,peak 9 ! ,selkirks 7aft] a plate by ! ,key/one ,plate ,co474 ,) ! gradual invasion ( ! upl& ^u :i* ! cirques h made _! attack1 ! area f :i* w9ds may ga!r up ! sn[ is /eadily dim9i%$1 & h5ce cirque recession is correspond+ly ret>d$4 ,cirques :i* h approa*$ ea* o!r f opposite sides ( ! ridge until !y h become tang5t at "o po9t may1 h[ev]1 /ill receive n\ri%m5t at ! sides & s cont9ue to cut d[n ! int]v5+ rock wall to =m a pass or col4 ,! !oretical curve :i* results f ?is int]section is t kn[n z ! hyp]bola1 ( :i* an illu/ration is af=d$ by ,fig4 #cif4 ,an approximation to ?is =m is cle>ly furni%$ by mo/ ( ! m\nta9 passes 9 glaciat$ m\nta9 di/ricts1 & a p>ticul>ly good illu/ration is furni%$ f ! vic9ity ( ,glaci] on ! l9e ( ! ,canadian ,pacific ,railway 7,fig4 #cig74 ,illu/ration3 ,,fig4 #cih4--;,diagrams to illu/rate ! progressive inve/m5t ( an upl& by cirques ) ! =mation ( comb ridges1 cols1 & horns4 ,i1 e>ly /age1 y\?2 ,,ii1 int]m$iate /age2 ,,iii1 late /age1 maturity4 ,^u ei!r side ( ! col ! l& mass is left 9 high relief1 ris+ f a m or less triangul> base 7,fig4 #cih1 ,,iii7 into a %>p horn or too?4 ,an illu/ration ( su* a horn is furni%$ by ! ,matt]horn 9 ! ,swiss ,alps1 or by ,m\nt ,sir ,donald 9 ! ,selkirks1 ?\gh less notewor?y examples may be f\nd 9 e maturely glaciat$ m\nta9 di/rict4 ,! features %ap$ b5ea? ! glaci]4--,^? features :i* are c>v$ above ! glaci]--! comb ridge1 ! col1 & ! horn--are all %ap$ z a result ( int5sive wea!r+ ^u ! cirque wall4 ,! %ap+ at l[] levels is accompli%$ by processes 9 op]ation bel[ ! glaci] surface1 :]e wea!r+ is exclud$ & :]e pluck+ & abrasion "w toge!r to te> away & gr9d (f ! rock surface4 ,by _! jo9t action ! valley is bo? deep5$ & wid5$1 directly to ! height ( ! glaci] surface1 & indirectly ?r\gh und]m9+ z f> up z rock ext5ds4 ,?us ! valley is trans=m$ into "o ( broad & flat b$ & precipit\s side walls--! ,u-%ap$ section illu/rat$ by valleys ( ! ,swiss ,alps & 9 fact 9 all di/ricts :i* h be5 /rongly glaciat$ by m\nta9 glaci]s 7,fig4 #cii74 ,illu/ration3 ,,fig4 #cii4--,! ,u-%ap$ ,k]n valley 9 ! ,si]ra ,nevadas ( ,cali=nia 7aft] ,w4 ,b4 ,scott74 ,z high up 9 ! valley z x has be5 occupi$ by ! glaci]1 ! b$ is r\nd$1 smoo!d1 & poli%$1 & m>k$ by ! *>act]i/ic glacial scor+s or /ri :i* po9t d[n ! valley4 ,above ! level ( ! glaci]'s upp] surface1 on ! o!r h&1 erosion is accompli%$ ?r\gh und]m9+ or sapp+1 a process :i* always leaves precipit\s slopes ( ragg$ surface made up ( ! jo9t planes on :i* ! fall5 blocks h sep>at$ f ! cliff4 ,?us !re is f\nd a %>p l9e :i* sep>ates ! smoo?ly r\nd$ rock surface bel[ f ! jagg$ & precipit\s "o above 7,fig4 #djj74 ,inasmu* z ?is b\nd>y usually sep>ates ! scalable f ! inaccessible slopes above1 sn[ is apt to lodge at ?is level & make x /rik+ly app>5t4 ,illu/ration3 ,,fig4 #djj4--;,glaciat$ valley wall 9 ! ,si]ra ,nevadas ( ,cali=nia1 %[+ ! %>p l9e :i* sep>ates ! abrad$ f ! und]m9$ rock surface 7aft] a photograph by ,fairbanks74 ,illu/ration3 ,,fig4 #dja4--,view ( ! ,vale ( ,*amonix f ! sracs ( ! ,glaci] des ,bossons4 ,! alb ( ! opposite side is well br\ght out4 ,if uplift ( ! l& occurs :ile glaci]s occupy ! valleys ( m\nta9s1 an increas$ capacity = deep5+ ! valley is imp>t$ to ^! ice /reams1 & we f9d1 z a result1 a deep c5tral valley ( ,u cross section excavat$ )9 a relatively broad tr\gh visible above ! %\ld] on ei!r side ( ! lat] furr[4 ,save only = its *>act]i/ic curves1 su* a valley be>s close resemblance to a mature /ream valley :i* has be5 rejuv5at$ 7see p4 #agc74 ,! remnants ( ! e>li] glaci]-c>v$ valley are1 z already /at$1 g5tly curv+ high t]races s common 9 ,switz]l&1 :]e !y are kn[n z albs or high m\nta9 mead[s4 ,^! albs may be se5 to special advantage on ! sides ( ! ,*amonix valley 7,fig4 #dja71 ! ,laut]brunn5 valley1 or 9 fact almo/ any ( ! l>g] ,alp9e valleys4 ,! cascade /airway 9 glaci]-c>v$ valleys4--,if n[1 in/ead ( giv+ our att5tion to ! cross section1 we foll[ ! c\rse ( ! valley t has be5 occupi$ by a glaci]1 we f9d t x desc5ds by a s]ies ( /eps or t]races hav+ _m backw>dly direct$ treads 7plate #ai71 :]eas a normal & well-e/abli%$ riv] valley has only =w>d grades4 ,because ( ^! backw>d grades ! /ream wat]s are imp\nd$1 & s lakes are f\nd /rung along ! valley 9 *a9s z ! l>g] beads are f\nd 9 a ros>y1 & ^! are ! *>act]i/ic rock bas9 lakes sometimes ref]r$ to z 8,pat]no/] ,lakes0 7see p4 #dab & ,fig4 #djb74 ,,plate #bj4 ,illu/ration3 ,map ( ! surface model$ by m\nta9 glaci]s 9 ! ,si]ra ,nevadas ( ,cali=nia 7aft] ,i4 ,c4 ,russell74 ,:5 ! backw>d grades ^u ! valley floor are especially /eep1 ! rock /ep becomes a rock b>1 or ,riegel1 ( :i* ne>ly e ,alp9e valley has its examples4 ,9 a walk f ! ,grimsel to ,meir+5 _m su* b>s are pass$4 ,c>ry+ 9 susp5sion ! %>p rock s& f ! glaci] deposits along its b$1 ! /ream :i* succe$s to ! glaci] z x vacates its valley saws its way ?r\gh ^! ob/ructions ) a rapidity t is amaz+1 ?us produc+ n>r[ defiles1 ( :i* ! ,gorge ( ! ,a> ne> ,meir+5 & t ( ! ,gorn] ne> ,z]matt are su* well-kn[n examples 7,fig4 #djc74 ,illu/ration3 ,,fig4 #djb4--,map ( an area ne> ! cont95tal divide 9 ,colorado1 %[+ an unglaciat$ surface to ! we/ ( ! divide1 :]e ! we/]ly w9ds h cle>$ ! gr\nd ( sn[1 & ! glaci]-c>v$ c\ntry to ! ea/w>d4 ,note ! regul> =ms ( ! y\?ful cirque1 ! glaci] /airway1 & ! rock bas9 lakes 7,u4 ,s4 ,g4 ,s474 ,illu/ration3 ,,fig4 #djc4--;,gorge ( ! ,albula ,riv] ne> ,b]kum 9 ! ,engad9e1 cut ?r\gh a rock b> by ! riv] :i* has succe$$ to ! e>li] glaci]4 ,illu/ration3 ,,fig4 #djd4--;,ideali/ic sket* %[+ bo? glaciat$ & nonglaciat$ side valleys tribut>y to a glaciat$ ma9 valley 7aft] ,davis74 ,x is *>act]i/ic ( riv]s t ! tribut>ies cut _! valleys m rapidly ?an does ! ma9 /ream )9 ! neighbor+ section1 ?\gh !y _c cut l[] ?an _! outlets--! side /reams ent] accordantly4 ,?is is easily expla9$ because ! grades ( ! tribut>y /reams are ! /eep]1 &1 z we well "k1 ! corrosion ( a valley is augm5t$ at a mo/ amaz+ rate = ea* increase ( its grade4 ,no su* law controls ! processes ( pluck+ & abrasion by :i* ! glaci] l[]s its floor1 = ^! processes appe> to dep5d = _! effici5cy ^u ! dep? ( ! ice1 & ! supply ( cutt+ tools1 q z mu* z ^u ! grade ( ! b$4 ,to apply a homely illu/ration1 ! holl[+ ( flag/ones ^u our walks is dep5d5t m ^u ! numb] ( p]sons t pass ov] !m1 & ^u _! size & ! numb] ( protrud+ nails 9 _! boot heels1 ?an ^u ! grades ^u :i* !y are plac$4 ,at all ev5ts we f9d t ! ma9 glaci] valleys are cut deep] ?an ! side valleys1 s t ! latt] become hang+ valleys--!y ent] ! ma9 valley1 n ^u its b$1 b "s di/ance above x 7,fig4 #djd74 ,! ,u-%ap$ hang+ valleys1 l ! ma9 valley1 are mu* too l>ge = ! /reams :i* n[ fill !m1 & ^! dim9utive side /reams plunge ov] ! /eep wall ( ! ma9 valley 9 ribbon-l falls s ?9 t ! w9d turns !m aside & disp]ses ! wat] 9 ! spray ( a 8bridal veil40 ,su* falls are f\nd by ! hundr$ 9 e glaciat$ m\nta9 di/rict1 imp>t+ to x "o ( ! greate/ ( its sc5ic *>ms4 ,illu/ration3 ,,fig4 #dje4--;,"* pr(iles 9 l&scapes sculptur$ by m\nta9 glaci]s4 ,illu/ration3 ,,fig4 #djf4--;,flat dome %ap$ "u ! m>g9 ( a ,norwegian ice cap ) project+ rock knobs & mora9es 9 =egr\nd4 ,! "* pr(iles :i* result f sculpture by m\nta9 glaci]s4--,! l9es :i* are repeat$ 9 l&scapes c>v$ by m\nta9 glaci]s are easy to recognize 7,fig4 #dje74 ,! highe/ horizon l9es are ! outl9es ( horns :i* are sep>at$ by cols4 ,m9>et-l palisades1 or 8files ( g5d>mes01 (t5 run = long di/ances z ! *>act]i/ic comb ridges4 ,l[] d[n & lack+ ! light] backgr\nd ( ! sky1 we make out ) less di/9ctness ! ,u-valley1 ei!r ) or )\t ! albs to %[ t ! sculptur+ process has be5 int]rupt$ by uplift4 ,illu/ration3 ,,fig4 #djg4--,two views illu/rat+ successive /ages 9 ! %ap+ ( t9ds or 8beehive0 m\nta9s4 ,! sculpture accompli%$ by ice caps4--,9 ! case ( ice caps1 ! only rock expos$ is f\nd 9 ! neighborhood ( ! m>g9--! project+ isl&s kn[n z nunataks4 ,x is ess5tial = ! exi/5ce ( ! ice cap t ! rock base %\ld h relatively slight irregul>ities comp>$ to ! dim5sions ( ! cap itself4 ,except 9 v high latitudes ?is base mu/ be some:at elevat$1 = l m\nta9 glaci]s ice caps are n\ri%$ by ! surface air curr5ts1 & _! sn[s are deposit$ above ! sn[ l9e4 ,! ,norwegian t9d or beehive m\nta94--,)9 temp]ate or tropical climes ! sn[ l9e lies s high t only ! l(ti] m\nta9s are able to support glaci]s4 ,x foll[s t ^? :i* are =m$ fl[ ^u relatively high grades ) correspond+ly high rate ( movem5t & increas$ cutt+ p[]4 ,)9 high latitudes ! sn[ is f\nd ne>] ! sea level1 & glaci]s are = ! mo/ "p correspond+ly sluggi% 9 _! movem5ts z well z less active d5ud+ ag5ts4 ,to ?is condition *>act]i/ic ( high latitude glaci]s1 !re is add$ 9 ,norway ano!r 9 ! peculi> %ape ( ! basem5t b5ea? ! rec5t & ! /ill exi/+ glaci]s4 ,! plateau ( ,norway is int]sect$ by a network ( deep & /eep wall$ fjords1 & ! glaci]s h develop$ z small ice caps p]*$ ^u v]itable p$e/als ( rock1 ov] ! m>g9s ( :i* _! outlet tongues ( ice desc5d on /eep slopes into ! fjord4 ,! tops ( ! p$e/als ?us come to be %ap$ by ! pluck+ & abrad+ processes into flat domes 7,fig4 #djf71 :ile ! knobs ( rock1 :i* z nunataks rea* above ! surface ( ! ice1 divide ! outfl[+ ice tongues at ! m>g9 ( ! p$e/al4 ,^! tongues be+ mu* m active d5ud+ ag5ts1 because ( _! /eep gradi5ts1 cont9ually l[] _! b$s1 ?us trans=m+ ! e>li] knobs ( rock into high & /eep m\nta9s ( m or less circul> base4 ,su* 8beehive0 m\nta9s ^u ! m>g9s ( ! fjords are ! *>act]i/ic ,norwegian t9ds 7,fig4 #djg74 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxvi ,i4 ,c4 ,,russell4 ,quat]n>y ,hi/ory ( ,mono ,valley1 ,cali=nia1 #h? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhi1 pp4 #cbi-cga1 pls4 #bg-cg4 ,f4 ,e4 ,,mat!s4 ,glacial ,sculpture ( ! ,bighorn ,m\nta9s1 ,wyom+1 #ba/ ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #aijj1 ,pt4 ii1 pp4 #agi-ahe1 pl4 #bc4 ,w4 ,d4 ,,johnson4 ,maturity 9 ,alp9e ,glacial ,erosion1 ,j\r4 ,geol41 vol4 #ab1 #aijd1 pp4 #efi-egh4 ,g4 ,k4 ,,gilb]t4 ,sy/ematic ,asymmetry ( ,cre/ ,l9es 9 ! ,high ,si]ras ( ,cali=nia1 ibid41 pp4 #egi-ehh4 ,,emm4 ,,de ,,m>tonne4 ,sur la ,=mation des ,cirques1 ,ann4 de ,gogr41 vol4 #aj1 #aija1 pp4 #aj-af4 ,w4 ,m4 ,,davis4 ,glacial ,erosion 9 ,nor? ,wales1 ,qu>t4 ,j\r4 ,geol4 ,soc4 ,lond41 vol4 #fe1 #aiji1 pp4 #bha-cej1 pl4 #ad4 ,,ed4 ,,br,,ckn]4 ,die ,glazial5 ,zge im ,antlitz d] ,alp51 ,naturw4 ,wo*5s*r41 ,n4 ,f41 vol4 #h1 #aiji4 ,,william ,h4 ,,hobbs4 ,*>act]i/ics ( ,exi/+ ,glaci]s1 pp4 #a-if4 ,,*apt] ,,xxvii ,,successive ,,glaci] ,,types ,,( ,a ,,wan+ ,,glaciation ,transition f ! ice cap to ! m\nta9 glaci]4--,a /udy ( exi/+ glaci]s leads inevitably to ! conclusion t al?\gh subject to %ort p]iod advances & retreats1 yet1 broadly speak+1 glaci]s are n[ gradually wa/+ away1 surr\nd$ by wide areas ^u :i* are ! evid5ces ( _! rec5t occupation4 ,we are ?us liv+ 9 a rec$+ hemicycle ( glaciation4 ,illu/ration3 ,,fig4 #djh4--,s*ematic diagram to %[ ! relation%ips ( glaci] types =m$ 9 succession dur+ a rec$+ hemicycle ( glaciation4 ,_m m\nta9 di/ricts :i* n[ support small glaci]s only1 or none at all1 7 once ne>ly or q subm]g$ b5ea? sn[ & ice4 ,if once cov]$ by an ice c>apace or cap1 our pres5t int]e/ 9 !m beg9s at t /age ( ! rec$+ hemicycle :5 ! rock surface has made its reappe>ance above ! surface ( ! sn[-ice mass4 ,at ?is /age int5sive fro/work1 ! *>act]i/ic high level wea!r+1 beg9s1 & cirques develop above ! sc>s ( ^? e>li] amphi!at]s =m$ 9 ! advanc+ hemicycle4 ,! pi$mont glaci]4--,9 ?is e>ly /age ( transition f ! ice cap to ! m\nta9 glaci]1 ! ice fl[s outw>d to ! m\nta9 front 9 ill-def9$ /reams divid$ by ! project+ ridges1 & ^u rea*+ ! m\nta9 front ^! /reams deploy ^u x s z to coalesce 9 a great /agnant ice apron ^: upp] surface slopes g5tly =w>d at an angle ( a few degrees at ! mo/ 7,fig4 #djh1 /age ,i74 ,?is is ! pi$mont glaci]1 a type f\nd to-day 9 ! high latitudes ( ,alaska & 9 ! s\!rn ,&es 7,fig4 #dji & pl4 #ah ,b74 ,illu/ration3 ,,fig4 #dji4--,map ( ! ,malasp9a glaci] ( ,alaska1 ! be/ kn[n ( exi/+ pi$mont glaci]s 7aft] ,russell74 ,dur+ ?is /age ! cirques may be b poorly def9$1 & ice fl[s 9 bo? directions f rock divides s t ! /reams transect ! range1 & lat]1 aft] ! glaci]s h disappe>$1 may expose a pass smoo!d & poli%$ ^u its floor & ) /ri direct$ 9 opposite directions f ! highe/ po9t4 ,! pass ( ! ,grimsel 9 ,switz]l& furni%es an excell5t illu/ration ( su* e>li] transection ( ! range4 ,illu/ration3 ,,fig4 #daj4--,map ( ! ,baltoro glaci] ( ! ,himalayas1 a typical glaci] ( ! d5dritic type4 ,! exp&$-foot glaci]4--,z air temp]atures cont9ue to become mild]1 ! glaci] /reams )9 ! m\nta9s are less deep & h5ce m cle>ly def9$1 & in/ead ( coalesc+ ^u ! m\nta9 =el&1 !y n[ issue f ! m\nta9s to =m individual aprons & are describ$ z exp&$-foot glaci]s 7,fig4 #djh1 /age ,,ii1 & ,fig4 #bib1 p4 #bfd74 ,illu/ration3 ,,fig4 #daa4--,! ,trie/ glaci]1 a hang+ glaci]et sep>at$ f ! ,great ,alets* glaci] to :i* x 0 lately a tribut>y4 ,! d5dritic glaci]4--,/ill lat] 9 ! hemicycle n\ri%m5t ( ! glaci]s is dim9i%$ z depletion f melt+ increases1 s t ! glaci] /reams no long] rea* to ! m\nta9 front4 ,bran*es cont9ue to ent] ! ma9 valley f ! sev]al side valleys l ! %ort bran*es ( a tall tree1 & because ( ?is arrangem5t su* a glaci] may be describ$ z a d5dritic glaci] 7,fig4 #djh1 /age ,,iii1 & ,fig4 #daj74 ,inasmu* z ! depletion f melt+ increases at a rapid rate 9 desc5d+ to l[] levels1 ! tribut>y glaci] valleys 8hang+0 above ! ma9 valley 9 ! l[] /ret*es become sep>at$1 & may cont9ue to exi/ z s]ies ( hang+ glaci]ets ^u ei!r side ( ! ma9 valley bel[ ! glaci] front 7,fig4 #djh1 /age ,,iii1 & ,fig4 #daa74 ,x mu/ be cle> f ?is t any attempt to "n ea* sep>at$ ice /ream )\t reg>d to its relation%ip mu/ lead to endless confusion1 = glaci] size is 9 su* s5sitive adju/m5t to air temp]ature t a fall or rise ( a few degrees only 9 ! av]age annual temp]ature ( ! di/rict may prove suffici5t to fuse _m glaci]s into "o or sep>ate "o ice mass into _m small] ones4 ,:5 9 high latitudes a d5dritic glaci] desc5ds 9 fjords to bel[ ! level ( ! sea1 x is attack$ by ! wat] 9 ! same mann] z are ! outlets ( ,gre5l& glaci]s1 & is !n kn[n z a 8tidewat] glaci]01 :i* may ?us be a subtype or v>iety ( ! d5dritic glaci] 7,fig4 #dab74 ,illu/ration3 ,,fig4 #dab4--,! ,h>riman fjord glaci] ( ,alaska1 a tidewat] v>iety ( d5dritic glaci] 7aft] a map by ,gannett74 ,! radiat+ 7,alp9e7 glaci]4--,9 ! progressive wa/+s ( d5dritic glaci]s1 !re comes a "t :5 _! d5dritic outl9es give place to radiat+ ones4 ,att5tion has already be5 call$ to ! division ( ! cirque into subord9ate bas9s sep>at$ by small rock artes & yield+ a m>k$ly scallop$ bord] 7,fig4 #cid1 p4 #cga74 ,:5 ! ice front retires f ! ma9 valley into "o ( ^! mature cirques1 ! n[ wa/$ ice /ream is brok5 up into subord9ate glaci]ets1 ea* ( :i* occupies "o ( ! bas9s )9 ! l>g] cirque1 & ^! ice /reams fl[ toge!r to produce a glaci] ^: compon5t elem5ts radiate l ! /icks )9 a lady's fan 7,fig4 #djh1 /age ,,iv1 & ,fig4 #dac74 ,illu/ration3 ,,fig4 #dac4--,map ( ! ,rotmoos glaci]1 a radiat+ glaci] ( ,switz]l& 7aft] ,sonkl>74 ,! horse%oe glaci]4--,z ! glaci] draws ne> to its f9al ext9ction1 x is cr[d$ h>d aga9/ ! wall ( ! amphi!at] 9 :i* x has s long be5 n\ri%$4 ,up to ?is /age x has (f]$ a swell+ front outw>dly convex z a direct consequ5ce ( ! laws controll+ its fl[4 ,no long] amply n\ri%$1 = ! fir/ "t its front is holl[$1 & x awaits its f9al dissolution curl$ up aga9/ ! cirque wall 7,fig4 #djh1 /age ,v1 & ,fig4 #dad74 ,practically all ! glaci]s ( ! ,unit$ ,/ates & s\!rn ,canada are ( ?is type4 ,! above classification is "o dep5d+ directly ^u glaci] n\ri%m5t1 & h5ce also ^u size1 & ^u ! /age ( ! glacial hemicycle4 ,9 ord] to det]m9e ! type ( any glaci] x is necess>y to "k ! outl9es ( ! m\nta9 valley--its divide--& ^? ( ! glaci] or glaci]s )9 x4 ,x is likely t ! types ( ! advanc+ hemicycle ( glaciation w\ld be mu* ! same1 save only = ! new-born or nivation glaci]1 :i* w\ld be z diff]5t z possible f ! horse%oe type1 to :i* 9 size x corresponds4 ,^u ! cont95t ( ,ant>ctica1 :]e ! abs5ce ( any g5]al melt+ ( ! ice1 ev5 9 ! summ] season & ne> ! sea level1 introduces special conditions1 "s additional glaci] types are f\nd1 :i*1 h[ev]1 x is n necess>y t we consid] "h4 ,illu/ration3 ,,fig4 #dad4--,outl9e map ( ! ,asulkan glaci] 9 ! ,selkirks1 a typical horse%oe glaci]4 ,! inh]it$-bas9 glaci]4--,x may be1 h[ev]1 t glaci]s h develop$1 n ^u m\nta9s %ap$ 9 a cycle ( riv] erosion1 nor yet 9 succession to an ice cap1 z 9 ! normal cases :i* we h consid]$4 ,on ! contr>y1 glaci]s may develop :]e bas9s ( "o sort or ano!r h be5 inh]it$ f ! prec$+ p]iod4 ,9 su* cases inh]it$ depressions may become m important ?an ! auto-sculpture ( ! glaci]4 ,glaci]s :i* develop "u su* conditions may be describ$ z inh]it$-bas9 glaci]s4 ,illu/ration3 ,,fig4 #dae4--,outl9e map ( ! ,illecillewaet glaci]1 an inh]it$-bas9 glaci] 9 ! ,selkirks4 ,a p>tly clos$ bas9 betwe5 ridges may supply a collect+ gr\nd = sn[s c>ri$ f neighbor+ slopes by ! w9d1 & s may yield a broad nv1 approa*+ 9 size a small ice cap1 yet )\t develop+ def9ite ice /reams except ^u its bord]4 ,su* a glaci] is ! ,illecillewaet glaci] ( ! ,selkirks 7,fig4 #dae74 ,aga9 9 l[ latitudes ! high & po9t$ volcanic peaks may pu% up beyond ! sn[ l9e into ! upp] atmosph]e1 & s become sn[-capp$4 ,def9ite cirques d n develop well "u ^! circum/ances1 & ! loose mat]ials ( :i* su* peaks are always compos$ are attack$ 9 some:at irregul> fa%ion f ! diff]5t sides4 ,?is is ! case ( ,m\nt ,ra9i] & simil> peaks ( ! ,cascade range ( ,nor? ,am]ica4 ,summ>y ( types ( m\nta9 glaci]4--,9 tabul> =m ! v>i\s types ( m\nta9 glaci] may be arrang$ z foll[s3-- ,,m\nta9 ,,glaci]s ,pi$mont glaci]4 ,m\nta9 valleys entirely occupi$ & l>gely subm]g$1 ) ov]fl[ ^u ! =el& to =m a common ice apron ?r\gh coalesc5ce ( neighbor+ /reams4 ,exp&$-foot glaci]4 ,valley entirely occupi$ & an ov]fl[ ^u ! =el& suffici5t to produce individual ice apron4 ,d5dritic glaci]4 ,valley n completely occupi$ b ) tribut>y ice /reams rang$ along ! sides ( ! ma9 /ream1 & ) hang+ glaci]ets sep>at$ ne> ! glaci] foot4 ,radiat+ glaci]4 ,glaci] l>gely includ$ 9 a cirque ) subord9ate glaci]ets conv]g+ bel[ l ! /icks 9 a lady's fan4 ,horse%oe glaci]4 ,small glaci] remnants hugg+ ! cirque wall & hav+ an incurv+ front4 ,inh]it$-bas9 glaci]4 ,( =m dep5d5t on a bas9 inh]it$ & n %ap$ by ! glaci] itself4 ,,read+ ,,ref]5ce ,,= ,,*apt] ,,xxvii ,,william ,h4 ,,hobbs4 ,! ,cycle ( ,m\nta9 ,glaciation1 ,geogr4 ,j\r41 vol4 #cg1 #aiaj1 pp4 #bfh-bhd4 ,,*apt] ,,xxviii ,,! ,,glaci]',s ,,surface ,,features ,,& ,,! ,,deposits ,,^u ,,its ,,b$ ,! glaci] fl[4--,! d[nw>d fl[ ( ! ice )9 a m\nta9 glaci] has be5 ! subject ( _m inve/igations & ! topic ( _m heat$ discussions s9ce ! "t :5 ,l\is ,agassiz & 8 companions set a l9e ( /akes across ! ,a> glaci] & numb]$ ! surface b[ld]s 9 prep>ation = repeat$ obs]vations4 ,_! fir/ obs]vation 0 t ! l9e ( /akes1 :i* _h run /raight across ! glaci]1 0 di/ort$ into a curve :i* 0 convex d[n/ream 7,fig4 #daf1 ,a71 ?us %[+ t ! surface lay]s h m rapid motion 9 proportion z !y are di/ant f ! side m>g9s4 ,summ>iz+ ^! & lat] /udies1 x may be /at$ t ! glaci] increases its rate ( motion f its side m>g9 t[>ds its c5t] l9e1 f its b$ upw>ds t[>ds its surface1 & bel[ ! nv ! velocity is greate/ :]e ! fall is greate/ & also :]ev] ! cross section dim9i%es4 ,9 all ^! p>ticul>s1 !n1 ! ice ( ! glaci] behaves l a /ream ( wat]4 ,! av]age rate ( fl[ ( ,alp9e glaci]s v>ies f a few in*es to a few feet p] day1 & is great] dur+ ! w>m summ] season4 ,! ,muir glaci] ( ,alaska has be5 %[n to move at ! rate ( ab\t sev5 feet p] day4 ,illu/ration3 ,,fig4 #daf4--;,diagram to illu/rate ! migrations ( l9es ( /akes cross+ a glaci]1 due to its surface movem5t1 ,a1 orig9al position ( l9es2 ,a1 lat] positions2 a & a1 orig9al & di/ort$ =ms ( a squ>e section ( ! glaci] surface ne> its m>g92 r1 r1 diagonal crevasses4 ,9 travel+ f ! nv d[nw>d to ! glaci] foot1 ! sn[ n only *anges into ice1 b x und]goes a granulat+ process ) cont9u$ increase 9 ! size ( ! nodules until at ! foot ( ! glaci] ^! may be pick$ out ( ! p>tially melt$ ice z articulat+ balls ! size ( ! fi/ or l>g]4 ,glaci] ice has !re=e a /ructure q diff]5t f t ( lake ice1 s9ce ! latt] is develop$ 9 p>allel ne$les p]p5dicul> to ! freez+ surface4 ,crevasses & sracs4--,prom95t surface indications ( glaci] movem5t are f\nd 9 ! op5 cracks or crevasses1 :i* are ! m>ks ( its yield+ to t5sional /resses4 ,crevasses are apt to run ei!r directly across ! glaci]1 :]ev] !re is a /eep desc5t ^u its b$1 or diagonally1 runn+ 9 f ! m>g9 & direct$ up-glaci] 7r1 r1 r1 ( ,fig4 #daf71 ?\gh !y occasionally run longitud9ally ) ! glaci] :5 !re is a rock t]race at ! side ( ! valley b5ea? ! ice4 ,! diagonal crevasses at ! glaci] m>g9 are due to ! m sluggi% movem5t :]e ! ice is held back by friction ^u ! walls ( ! valley1 z w be cle> f ,fig4 #daf4 ,! squ>e a has by ?is movem5t be5 di/ort$ into ! loz5ge a1 s t ! l9e xy has be5 ext5d$ into xy1 ) ! obvi\s t5d5cy to op5 cracks 9 ! direction ss4 ,e glaci] surface bel[ its nv is m>k$ by /eps or t]races1 :i* are well und]/ood to ov]lie correspond+ /eps ( ! cascade /airway to be se5 9 all vacat$ glaci] valleys 7plate #ai74 ,! /eep ris]s ( ^! /eps are usually m>k$ by p>allel crevasses :i* cross ! glaci]4 ,"u ! rays ( ! sun1 :i* /rike !m m f "o side ?an f ! o!r1 ! slices into :i* ! ice is divid$ are trans=m$ into %>p5$ blades & ne$les :i* are kn[n z sracs 7,fig4 #dja1 p4 #cgf1 & ,fig4 #dag74 ,illu/ration3 ,,fig4 #dag4--,transv]se crevasses at ! fall bel[ a glaci] /ep trans=m$ by unsymmetrical melt+ into sracs4 ,! num]\s crevasses tell u t ! ice is _m times wr5*$ ap>t dur+ its j\rney d[n ! glaci]4 ,?is has be5 illu/rat$ by some:at grewsome incid5ts connect$ ) accid5ts to ,alp9i/s1 b z !y illu/rate 9 "s measure bo? ! mode & ! rate ( motion ( ,swiss glaci]s1 !y are wor?y ( our consid]ation4 ,bodies giv5 up by ! ,glaci] des ,bossons4--,9 ! ye> #ahbj1 dur+ "o ( ! e>li] asc5ts ( ,mont ,blanc1 ?ree guides 7 buri$ b5ea? an avalan*e ne> ! ,ro*]s ,r\ges 9 ! nv ( ! ,glaci] des ,bossons 7,fig4 #dah74 ,9 #aheh ,dr4 ,=bes1 :o _h measur$ ! rate ( fl[ ( a numb] ( ,alp9e glaci]s1 pr$ict$ t ! bodies ( ! victims ( ?is accid5t w\ld be giv5 up by ! glaci] aft] be+ entomb$ f ?irty-five to =ty ye>s4 ,9 ! ye> #ahfa1 or =ty-"o ye>s aft] ! disa/]1 ! heads ( ! ?ree guides1 sep>at$ f _! bodies1 ) "s h&s & fragm5ts ( clo?+1 appe>$ at ! foot ( ! ,glaci] des ,bossons1 & 9 su* a /ate ( pres]vation t !y 7 easily recogniz$ by a guide :o _h kn[n !m 9 life4 ,inasmu* z ^! fragm5ts ( ! bodies _h requir$ =ty-"o ye>s to travel 9 ! ice ! ?ree ?\s& met]s :i* sep>ate ! place ( ! accid5t f ! foot ( ! glaci]1 ! rate ( movem5t 0 tw5ty c5timet]s1 or eight in*es1 p] day4 ,illu/ration3 ,,fig4 #dah4--,view ( ! ,glaci] des ,bossons ^u ! slopes ( ,mont ,blanc %[+ ! position ( accid5ts to ,alp9i/s & ! place ( reappe>ance ( _! bodies4 ,illu/ration3 ,,fig4 #dai4--,l9es ( fl[ ^u ! surface ( ! ,h9t]eisf]n] glaci] 9 ! ,alps 7aft] ,hess74 ,v>i\s sep>at$ p>ts ( ! body ( ,capta9 ,arkwright1 :o _h be5 lo/ 9 #ahff ^u ! nv ( ! same glaci]1 reappe>$ at its foot aft] entombm5t 9 ! ice = a p]iod ( ?irty-"o ye>s4 ,to-day ! "t ( reappe>ance ( portions ( ! bodies ( p]sons lo/ ^u ,mont ,blanc is r accurately pr$ict$1 s t fri5ds repair to ,*amonix to await ! giv+ up ( its victims by ! ,glaci] des ,bossons4 ,illu/ration3 ,,fig4 #dbj4--,lat]al & m$ial mora9es ( ! ,m] de glace & its tribut>y ice /reams4 ,! mora9es4--,! horns & comb ridges :i* rise above ! glaci] surface are cont9ually subject to fro/ wea!r+1 & f "t to "t drop _! sep>at$ fragm5ts ^u ! glaci]4 ,fall+ z ^! d f consid]able heights1 !y rea* ! ice "u a high velocity1 & reb\nd+1 sometimes travel well out ^u its surface be=e com+ to a tempor>y re/4 ,^u a fre% sn[ surface ( ! nv _! tracks may sometimes be foll[$ ) ! eye = consid]able di/ances1 & _! fall is a con/ant m5ace to ,alp9e climb]s4 ,bel[ ! nv ! l>g] numb] ( su* fragm5ts rema9 ne> ! cliff1 & ! l9es ( fl[ ( ! ice )9 ! glaci] surface are su* t blocks :i* rea* po9ts f>!r out ^u ! glaci] are lat] ga!r$ 9 b5ea? ! cliff at ! side 7,fig4 #dai74 ,! ridge ( angul> rock dbris :i* ?us =ms at ! side ( ! glaci] is call$ a lat]al mora9e 7see ,fig4 #daa1 p4 #che1 & ,fig4 #dbj74 ,at ! junction ( two glaci] /reams1 ! lat]al mora9es are jo9$1 & !re move out ^u ! ice surface ( ! resultant glaci] z a m$ial mora9e4 ,?us f ! numb] ( m$ial mora9es ^u a glaci] surface x is possible to say t ! important tribut>y glaci]s numb] "o m 7,fig4 #dbj74 ,illu/ration3 ,,fig4 #dba4--;,ideal cross-section ( a m\nta9 glaci] to %[ ! position ( mora9es & o!r peculi>ities *>act]i/ic ( ! surface ( ! b$4 ,! pluck+ & abrad+ processes 9 op]ation b5ea? ! glaci]1 qu>ry ! rock ^u its b$1 & aft] %ap+ & smoo?+ ! sep>at$ rock fragm5ts1 ^! are incorporat$ )9 ! l[] lay]s ( ! ice z englacial rock dbris4 ,9 spaces favorable = its accumulation1 a portion ( ?is mat]ial1 toge!r ) mu* f9] dbris & rock fl\r1 is left beh9d z a gr\nd mora9e ^u ! b$ ( ! glaci] 7see ,fig4 #dba74 ,illu/ration3 ,,fig4 #dbb4--;,fragm5ts ( rock ( diff]5t sizes1 to br+ out _! diff]5t effects ^u ! melt+ ( ! glaci] surface4 ,at ! foot ( ! glaci] ! relatively angul> rock dbris1 :i* has be5 c>ri$ ^u ! surface1 & ! sol$ & poli%$ englacial mat]ial f ne> ! bottom1 are alike deposit$ 9 a common m>g9al ridge kn[n z ! t]m9al or end mora9e 7plate #ba ,b74 ,,plate #ba4 ,illu/ration3 ,a4 ,view ( ! ,h>v>d ,glaci]1 ,alaska1 %[+ ! *>act]i/ic t]races 7aft] ,u4 ,s4 ,grant74 ,illu/ration3 ,b4 ,! t]m9al mora9e at ! foot ( a m\nta9 glaci] 7aft] ,george ,k9ney74 ,selective melt+ ^u ! glaci] surface4--,! :ite surface ( ! glaci] g5]ally reflects a l>ge proportion ( ! sun's rays :i* rea* x1 & its m rapid melt+ is l>gely accompli%$ ?r\gh ! ag5cy ( rock fragm5ts spread ^u its surface4 ,su* fragm5ts1 h[ev]1 promote or ret>d ! melt+ process 9 inv]se proportion to _! size up to a c]ta9 limit1 & above t size _! action is always to protect ! glaci] f ! sun4 ,?is nice adju/m5t to ! size ( ! rock fragm5ts w be cle> f exam9ation ( ,fig4 #dbb1 = rock is a poor conductor ( heat1 & 9 ev5 ! longe/ summ] day a ?9 out] lay] only is appreciably w>m$4 ,l>ge rock blocks1 gr\p$ 9 ! m$ial & lat]al mora9es1 hold back ! process ( l[]+ ! glaci] surface dur+ ! summ]1 s t late 9 ! season ^! mora9es /& fifty feet or m above ! glaci] z armor$ ice ridges4 ,illu/ration3 ,,fig4 #dbc4--,small glaci] table ^u ! surface ( ! ,great ,alets* glaci] 9 #aijh4 ,isolat$ & l>ge rock slabs1 z ! season advances1 may come to =m ! capp+ ( an ice p$e/al :i* !y ov]hang & are kn[n z glaci] tables 7,fig4 #dbc74 ,su* tables ! sun attacks m ^u "o side ?an ^u ! o!r1 s t ! slab incl9es m & m to ! s\? & may ev5tually slip d[n until its edges re/ aga9/ ! glaci] surface4 ,r\nd$ b[ld]s1 :i* less frequ5tly become p]*$ ^u ice p$e/als1 may1 f a simil> process1 slide d[n ^u ! s\!rn side & leave a pyramid ( ice furr[$ ^u ?is side & kn[n z an ice pyramid4 ,f9e dirt :5 scatt]$ ov] ! glaci] surface is1 on ! o!r h&1 mo/ effective 9 l[]+ its level by melt+4 ,use 0 made ( ?is k to l[] ! great drifts ( sn[ :i* _h to be remov$ ea* season dur+ ! con/ruction ( ! new ,b]g5 railway ( s\!rn ,norway4 ,ea* dirt p>ticle1 be+ w>m$ ?r\gh\t by ! sun's rays1 melts its way rapidly into ! glaci] surface until ! du/ well :i* x has =m$ is s deep t ! slant+ rays ( ! sun no long] rea* x4 ,:5 ! dirt p>ticles are ne> toge!r1 ! ?9 walls :i* sep>ate ! du/ wells are attack$ f ! sides 9 ! w>m air ( summ] days1 ?us produc+ f a pat* ( dirt ^u ! glaci] surface a ba? tub 7,fig4 #dbd d74 ,at night ! wat] :i* fills ^! bas9s is froz5 to =m a l9+ ( ice ne$les project+ inw>d f ! wall1 & ?is1 repeat$ 9 succe$+ nights1 may entirely close ! bas9 ) wat] ice & produce ! famili> glaci] /> 7,fig4 #dbd c74 ,illu/ration3 ,,fig4 #dbd4--;,effects ( diff]5tial melt+ & subsequ5t refreez+ ^u ! glaci] surface4 a1 du/ wells2 b1 glaci] tub produc$ by melt+ ab\t a gr\p ( scatt]$ du/ p>ticles2 c1 glaci] /> produc$ :5 ! inclos$ wat] ( ! glaci] well has froz5 9 successive nights2 d1 8ba? tub40 ,if ! dirt ^u ! glaci] surface1 in/ead ( be+ scatt]$1 is s dispos$ z to make a pat* completely cov]+ ! ice to ! ?ickness ( an in* or m1 ! effect is altoge!r diff]5t4 ,protect+ z x n[ does ! ice bel[1 a local ice hillock rises ^u its site z ! surr\nd+ surface is l[]$1 & z ?is gr[s 9 height its declivities increase & a portion ( ! dirt slides d[n ! side4 ,! f9al product ( ?is %ap+ is an almo/ p]fectly conical ice hill encas$ 9 dirt & kn[n z a dbris1 s&1 or dirt cone 7,fig4 #dbe74 ,! novice 9 glaci] /udy is apt to assume t ^! black cones conta9 only dirt1 b is rudely awak5$ to ! reality :5 he attempts to kick !m to pieces4 ,bo? glaci] tubs & dbris cones may assume l>ge dim5sions2 z1 = example1 9 ,alaska1 :]e !y may be prop]ly describ$ z lakes & hills4 ,illu/ration3 ,,fig4 #dbe4--;,dirt cone & "o ) its cas+ 9 "p remov$4 ,victoria glaci] 7aft] ,%]z]74 ,a pat* ( h>d & d5se sn[ :i* is less easily melt$ ?an t ^u :i* x re/s may lead to ! =mation ( sn[ cones ^u ! glaci] surface simil> 9 size & %ape to ! bett] kn[n dbris cones4 ,su* cones ( sn[ h1 ) d\btful propriety1 be5 designat$ 8p5it5ts01 = x is pretty cle> t ! int]e/+ b[$ sn[ figures1 :i* really resemble p5it5ts & :i* 7 fir/ describ$ f ! s\!rn ,&es "u ! "n ( nieves p5it5tes1 are ( some:at diff]5t "*4 ,illu/ration3 ,,fig4 #dbf4--,s*ematic diagram to %[ ! mann] ( =mation ( glaci] cornices4 ,"o fur!r ice feature %ap$ by diff]5tial melt+ ar\nd rock p>ticles rema9s to be m5tion$4 ,:]ev] ! seasonal sn[falls ( ! nv are expos$ 9 crevasses1 !y are g5]ally f\nd to be sep>at$ by lay]s ( dirt1 & l9es ( pebbles simil>ly sep>ate ^? ice lay]s :i* are reveal$ at ! foot ( ! glaci]4 ,9 ei!r case1 if ! sun's rays c rea* ^! lay]s 9 an op5$ crevasse1 ! half-buri$ rock fragm5ts are w>m$ by ! sun ^u _! expos$ surfaces & sl[ly melt _! way d[n ! ice surface1 ?us remov+ f x a ?9 lay] ( sn[ or ice & caus+ t "p above ! pebble lay] to project l a cornice4 ,?is process w g on until ! ov]hang+ cornice protects ! pebbles f any fur!r w>m+ by ! sun1 b ea* l[] pebble lay] t is rea*$ by ! sun w produce an additional cornice1 s t ! orig9al surface may at ! bottom h be5 retir$ by ! process a numb] ( in*es4 ,^! features are describ$ z glaci] cornices 7,fig4 #dbf74 ,illu/ration3 ,,fig4 #dbg4--,sup]glacial /ream ^u ! ,great ,alets* glaci]4 ,glaci] dra9age4--,already 9 ! e>ly morn+ ( e w>m summ] day1 active melt+ has begun ^u ! surface ( ! ,swiss glaci]s4 ,rills ( icy wat] soon make _! way along depressions ^u ! surface1 & are jo9$ to "o ano!r s t !y sometimes =m brooks ( consid]able size 7,fig4 #dbg74 ,su* /reams cont9ue _! s]p5t9e c\rses until ^! are int]sect$ by a crevasse d[n :i* ! wat]s plunge 9 a :irl+ vortex :i* soon develops a v]tical %aft ( circul> section )9 ! ice4 ,su* %afts ) _! desc5d+ columns ( :irl+ wat] are ! well-kn[n m\l9s1 or 8mills01 :i* may be detect$ f a di/ance by _! gurgl+ s\nds4 ,! fir/ plunge ( ! wat] may n rea* to ! bottom ( ! glaci]1 9 :i* case ! /ream f9ds a passageway bel[ ! surface b above ! floor until ano!r crevasse is enc\nt]$ & a new plunge made1 "h p]haps to ! bottom4 ,once ^u ! valley floor ! /ream is jo9$ by o!rs1 & pursues its c\rse )9 an ice tunnel ( its own mak+ 7,fig4 #dba1 p4 #cid7 until x issues at ! glaci] front4 ,! co>s] ( ! rock dbris :i* 0 ga!r$ up by ! /ream ^u ! glaci] surface is deposit$ )9 ! tunnel 9 imp]fect assortm5t 7gravel & s&71 :ile all f9] mat]ial & t lift$ f ! floor 7rock fl\r7 is reta9$ 9 susp5sion & gives to ! escap+ /ream its opaque :ite appe>ance4 ,?is glaci] milk may g5]ally be trac$ f> d[n ! valleys or out ^u ! =el&1 & is (t5 ! travel]'s fir/ indication t a range :i* he is approa*+ supports glaci]s4 ,illu/ration3 ,,fig4 #dbh4--;,ideal =m ( ! surface left on ! site ( ! apron ( a pi$mont glaci]4 ,m1 mora9e2 ,t1 outwa%2 ,c1 bas9 usually occupi$ by a lake2 ,d1 druml9s 7aft] ,p5ck74 ,deposits )9 ! vacat$ valley4--,= e excavation ( ! high] portions ( ! upl& ?r\gh glacial sculpture1 !re is a correspond+ deposit ( ! excavat$ mat]ials 9 l[] levels4 ,s f> z ^! mat]ials are deposit$ directly by ! ice1 !y =m ! lat]al1 m$ial1 gr\nd1 & t]m9al mora9es already describ$4 ,a consid]able proportion ( !m are1 h[ev]1 deposit$ by ! wat] outside ! t]m9al mora9e2 b z ) ! %r9k+ glaci] ! ice front retires 9 halt+ movem5ts ov] ! area e>li] ice-cov]$1 ! t]m9al mora9es are rang$ along ! vacat$ valley z recessional mora9es1 ea* ) a valley tra9 ( outwa% bel[4 ,ab\t ! apron ( ! pi$mont glaci]1 su* deposits are p>ticul>ly heavy 7,fig4 #dbh74 ,dur+ ! 8ice age0 ! ,swiss glaci]s ext5d$ d[n ! valleys bel[ ! exi/+ ice remnants & spread ^u ! ,swiss =el& z great pi$mont glaci]s su* z may n[ be se5 9 ,alaska4 ,to-day we f9d !re mora9es & glacial outwa%1 a lake 9 ! middle ( ! apron site1 & sometimes a gr\p ( radiat+ druml9s l ^? f\nd )9 ! ice lobes ( ! cont95tal glaci] 9 s\!rn ,wiscons9 7,fig4 #dbi1 & ,fig4 #cdd1 p4 #cag74 ,illu/ration3 ,,fig4 #dbi4--,mora9es & druml9s ab\t ,lake ,con/ance ^u ! site ( ! e>li] pi$mont glaci] ( ! ,upp] ,rh9e4 ,! :ite area outside ! out]mo/ mora9e is buri$ 9 glacial outwa% 7aft] ,p5ck & ,brckn]74 ,beh9d ! recessional mora9es )9 ! glaciat$ valley are f\nd ! valley mora9e lakes 7,fig4 #ddh1 p4 #dac71 9 association ) ! rock bas9 lakes due to glacial sculpture 7,fig4 #ddg1 p4 #dab74 ,aft] ! glaci] has vacat$ its valley1 ! precipit\s side walls become ! prey ( fro/work & are ! sc5es ( disa/r\s avalan*es or l&slides4 ,)9 ! cirques1 drifts ( sn[ are n\ri%$ long aft] ! ice has disappe>$1 & z a consequ5ce ! amphi!at] walls succumb to ! process ( solifluxion 7p4 #aec74 ,div]sions & rev]sals ( dra9age1 :i* are s *>act]i/ic ( ! "w ( cont95tal glaci]s1 are h>dly less common to glaciat$ m\nta9 di/ricts4 ,_m ( our mo/ beautiful wat]falls h result$ f ei!r ! tempor>y or p]man5t ob/ruction ( e>li] valleys above ! falls4 ,! fam\s ,yosemite ,falls (f]s an int]e/+ illu/ration ( ! %ift+ ( an e>li] wat]fall1 itself no d\bt due to ice block+ 9 a /ill e>li] glaciation 7plate #bb ,b74 ,m>ks ( ! e>li] occupation ( m\nta9s by glaci]s4--,x is well t we %\ld n[ br+ toge!r )9 a small compass ^? evid5ces by :i* ! exi/5ce ( e>li] m\nta9 glaci]s may be prov5 9 any di/rict4 ,^! m>ks are s deeply /amp$ ^u ! l&scape t no "o ne$ err 9 _! int]pretation4 ,,m>ks ,,( ,,m\nta9 ,,glaci]s ,high-level sculpture4 ,! groov$ upl& ) its cirques1 or ! frett$ upl& ) its cirques1 cols1 horns1 & comb ridges4 ,l[-level sculpture4 ,! ,u-%ap$ ma9 valley1 ! hang+ side valleys ) _! ribbon falls1 ! glaci] /aircase ) its rock b>s & gorges1 ! r\nd$1 poli%$1 & /riat$ rock floor4 ,deposits4 ,! recessional mora9es ( till & ! valley tra9s ( s& & gravel1 ! sol$ erratic blocks d]iv$ always f high] levels ( ! valley4 ,lakes4 ,! valley mora9e lakes & ! *a9s ( rock bas9 lakes4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxviii ,glaci] movem5t3-- ,l4 ,,agassiz4 ,n\velles tudes et ,expri5ces sur les ,glaci]s ,actuels1 etc41 ,p>is1 #ahdg1 pp4 #dce-eci4 ,h4 ,,hess4 ,die ,glets*]1 ,brauns*weig1 #aijd1 pp4 #aae-aej4 ,h4 ,f4 ,,reid4 ,! ,me*anics ( ,glaci]s1 ,j\r4 ,geol41 vol4 #d1 #ahif1 pp4 #iab-ibh2 ,glaci] ,bay & ,its ,glaci]s1 #af? ,ann4 ,rept4 ,u4 ,s ,geol4 ,surv41 ,pt4 i1 #ahih1 pp4 #dde-ddh4 ,,plate #bb4 ,illu/ration3 ,a4 ,model ( ! vic9ity ( ,*icago1 %[+ ! position ( ! anci5t bea*es & ! outlet ( ! =m] ,lake ,*icago4 ,illu/ration3 ,b4 ,map ( ,yosemite ,falls & its e>li] site ne> ,eagle ,peak 7aft] ,f4 ,e4 ,mat!s74 ,,*apt] ,,xxix ,a ,,/udy ,,( ,,lake ,,bas9s ,fre%wat] & sal9e lakes4--,lakes require = _! exi/5ce a bas9 )9 :i* wat] may be imp\nd$1 & a supply ( wat] m ?an suffici5t to meet ! losses f seepage & evaporation4 ,if !re is a surplus beyond :at is ne$$ to meet ^! losses1 lakes h outlets & rema9 fre%2 _! cont5t ( m9]al matt] is !n too slight to be detect$ by ! palate4 ,if1 on ! o!r h&1 supply is insuffici5t = ov]fl[1 cont9u$ evaporation results 9 a conc5tration ( ! m9]al cont5t ( ! wat]1 subject z x is to cont9ual augm5tation f ! infl[+ /reams4 ,z we h se51 !re are 9 areas ( small ra9fall special wea!r+ processes :i* t5d to br+ out ! salts f ! int]ior ( rock masses1 ^! conc5trat$ salts g5]ally fir/ appe>+ z a surface effloresc5ce :i* is ultimately transf]r$ ?r\gh ! ag5cy ( w9d & cl\dbur/ to ! *>act]i/ically sal9e des]t lakes4 ,lake bas9s may be =m$ 9 _m ways4 ,depressions ( ! l& surface may result f tectonic movem5ts ( ! cru/2 !y may be =m$ by excavat+ processes2 b 9 by f> ! great] numb] ( in/ances !y result f ! ob/ruction 9 "s mann] ( valleys :i* 7 be=e *>act]iz$ by uni=mly =w>d grades4 ,9 relatively few cases loose mat]ials are heap$ up 9 su* a mann] z to produce fairly symmetrical bas9s4 ,illu/ration3 ,,fig4 #dcj4--,map & diagram to br+ out ! *>act]i/ics ( newl& lakes4 ,newl& lakes4--,on l& rec5tly elevat$ f ! sea1 bas9s ( lakes may be m]ely ! inh]it$ slight irregul>ities ( ! e>li] sea floor1 9 :i* case !y may be assum$ to be l>gely ! result ( an irregul> di/ribution ( deposits d]iv$ f ! l&4 ,lakes ( ?is type are especially well exhibit$ 9 ,florida1 & are kn[n z newl& lakes 7,fig4 #dcj74 ,su* lakes are exceptionally %all[1 & are apt to h irregul> outl9es & extremely l[ banks4 ,"u ^! circum/ances1 !y are soon fill$ ) a rank gr[? ( vegetation1 s t x is sometimes difficult to prop]ly di/+ui% lake & m>%4 ,illu/ration3 ,,fig4 #dca4--,view ( ! ,w>n] ,lakes1 ,oregon 7aft] ,russell74 ,illu/ration3 ,,fig4 #dcb4--,s*ematic diagrams to illu/rate ! *>act]i/ics ( bas9-range lakes4 ,bas9-range lakes4--,newl& lakes may be said to h _! orig9 9 an uplift ( ! l& & sea floor ne> _! common m>g94 ,a lake type dep5d5t ^u movem5ts ( ! e>?'s cru/ b )9 int]ior areas has be5 describ$ z ! bas9-range type & is exemplifi$ by ! ,w>n] ,lakes ( ,oregon4 ,9 ?is di/rict great rectangul> blocks ( ! e>?'s cru/1 :i* 9 _! upp] portions at lea/ are compos$ ( basaltic lavas1 h und]gone v]tical adju/m5ts 9 level & h be5 tilt$ s t ! correspond+ corn]s ( neighbor+ blocks h be5 giv5 a simil> degree ( d[n-tilt 7,fig4 #dca74 ,lakes =m$ 9 ?is way are ( triangul> outl9e1 are b\nd$ on ! two %ort] sides by cliffs1 b h extremely flat %ores on _! longe/ side4 ,f ?is %ore ! wat] increases gradually 9 dep? & atta9s a maximum dep? at or ne> ! opposite angle4 ,su* lakes naturally betray a t5d5cy to appe> 9 s]ies 7,fig4 #dcb71 & are un=tunately mu* too (t5 illu/rat$ on a small scale aft] a %[] by ! tilt$ blocks ( imp]fectly made cem5t sidewalks4 ,illu/ration3 ,,fig4 #dcc4--,s*ematic diagrams ( rift-valley lakes1 & ! rift valley ( ! ,jordan ) ! ,dead ,sea & ! ,sea ( ,galilee z remnants ( a l>g] lake 9 :i* _! bas9s 7 includ$4 ,rift-valley lakes4--,ano!r type ( lake bas9 :i* has its orig9 9 fault$ block movem5ts is kn[n z ! rift-valley lake1 & is be/ exemplifi$ by ! great lakes ( ea/ ,c5tral ,africa4 ,9 ?is type a /rip ( cru/1 _m times z long z x is wide1 has be5 relatively sunk betwe5 ! blocks on ei!r side s z to produce a deep rift1 or :at 9 ,g]many is kn[n z a ,grab5 7tr5*74 ,su* a bas9 :5 occupi$ by wat] yields a lake :i* is long1 /raight1 deep1 & n>r[1 & is 9 addition b\nd$ on ! sides by /eep rock cliffs4 ,at ! ends ! %ores are g5]ally by contra/ decid$ly l[4 ,if ! h>d rock at ! bottom ( ! lake c\ld be exam9$1 x w\ld be f\nd to be ( ! same type z t expos$ ne> ! top ( ! side cliffs4 ,! valley ( ! ,jordan 9 ,pale/9e is a rift ( ?is "* & 0 at "o "t occupi$ by a long & n>r[ lake ( :i* ! ,dead ,sea & ! ,sea ( ,galilee are ! exi/+ remnants 7,fig4 #dcc74 ,illu/ration3 ,,fig4 #dcd4--,map %[+ ! rift valley lakes ( ea/ ,c5tral ,africa4 ,"o ( ! mo/ /rik+ examples ( a rift valley lake is ,lake ,tanganyika1 :ile ,alb]t ,nyanza1 ,nyassa1 & ,rudolf 9 ! same region are simil> 7,fig4 #dcd74 ,illu/ration3 ,,fig4 #dce4--;,e>?quake lakes :i* 7 =m$ 9 ! flood pla9 ( ! l[] ,mississippi dur+ ! e>?quake ( #ahaa 7aft] ,humphreys74 ,e>?quake lakes4--,! complex adju/m5ts 9 level ( ! surface ( ! gr\nd at ! "t ( s5sible e>?quakes are _m ( !m made app>5t 9 no o!r way ?an by ! d]angem5ts ( ! surface wat]4 ,?is is at su* times imp\nd$ ei!r 9 pools or 9 broad lakes1 :i* inasmu* z !y date f kn[n e>?quakes h be5 call$ 8e>?quake lakes01 ev5 ?\gh 9 a /rict s5se any lake :i* has orig9at$ 9 e>? movem5ts might prop]ly be reg>d$ z an e>?quake lake4 ,to avoid unnecess>y confusion1 ! t]m mu/1 h[ev]1 be re/rict$ to ^? lakes :i* are kn[n to h be5 =m$ at ! "t ( def9ite e>?quakes 7,fig4 #dce74 ,reelfoot ,lake 9 ,t5nessee1 :i* 9 late ye>s has acquir$ undesirable notoriety because ( ! feuds betwe5 ! fi%]m5 ( ! di/rict & ! con/itut$ au?orities1 is a lake m ?an tw5ty miles across & came into exi/5ce dur+ ! great e>?quake ( ! l[] ,mississippi valley 9 #ahaa4 ,crat] lakes4--,! crat]s ( volcanic m\nta9s are natural bas9s 9 :i* surface wat]s are c]ta9 to be collect$1 provid$ only ! supply is suffici5t & seepage into ! loose mat]ials is n excessive4 ,"s crat]s1 /ill visibly m or less active1 are occupi$ by lakes 7,fig4 #dcf74 ,illu/ration3 ,,fig4 #dcf4--,view ( lake 9 ,poas ,crat] 9 ,co/a ,rica1 a volcanic crat] m ?an half a mile across & ) walls #hjj feet deep4 ,at int]vals !re is an ejection ( /eam mix$ ) mud & a% aft] ! mann] ( a geys] 7aft] ,h4 ,pitti]74 ,9 ! l>g] numb] ( cases 9 :i* crat]s become occupi$ by lakes1 ! evid5ce ( cont9u$ activity is lack+1 & x w\ld appe> 9 su* cases t ! lava ( ! *imney _h consolidat$ into a volcanic plug1 clos+ ! bottom ( ! crat]4 ,notable gr\ps ( crat] lakes are ! ,cald]a ( ! ,roman ,campagna 7,fig4 #dcg7 & ! s-call$ ma>e ( ! ,eifel ab\t ! ,l[] ,rh9e4 ,crat] lakes are easy to recognize by _! circul> plan1 _! /eep walls ( volcanic mat]ials1 & _! consid]able dep? ) a maximum ne> ! c5t]4 ,"o ( ! mo/ rem>kable ( ^! wat]-fill$ bas9s is ,crat] ,lake 9 ,oregon1 :i* has a diamet] ( ab\t six miles & is believ$ to h result$ f ! incav+ ( a great volcanic cone 9 ! late/ /age ( its activity4 ,?is rem>kable feature has n[ be5 made a national p>k & w soon be conv5i5tly rea*$ by t\ri/s & c\nt$ "o ( ! greate/ nature wond]s ( ! ,pacific slope4 ,illu/ration3 ,,fig4 #dcg4--;,diagrams to illu/rate ! *>act]i/ics ( crat] lakes4 ,! ,roman ,campagna is a pla9 =m$ ( volcanic a%1 ) ! crat] lakes ( ,bracciano1 ,vico1 & ,bols5o arrang$ on a l9e trav]s+ x4 ,c\le lakes4--,f> m important z lakes are ^? volcanic bas9s :i* arise f ! fl[ ( a /ream ( lava across ! valley ( a riv] s z to imp\nd its wat]s 7,fig4 #dch74 ,at ! "t ( ! great eruption "u ,skaptr ,jkull 9 #aghc ! riv] ,skaptr & _m ( its tribut>ies 7 block$ by ! fl[ ( lava1 :i* x is e/imat$ exce$$ 9 bulk ! mass ( ,mont ,blanc4 ,illu/ration3 ,,fig4 #dch4--,view ( ,snag ,lake1 a c\le lake ) lava dam %[n 9 middle di/ance 7aft] ,fairbanks74 ,mora9al lakes4--,z we h le>n$1 ! ob/ruction ( dra9age1 due to ! di/ribution ( rock dbris by cont95tal glaci]s1 has yield$ lakes 9 almo/ c\ntless numb]s4 ,probably n9ety p] c5t or m ( ! kn[n lakes h _h ?is orig91 & ! type is s common )9 ! once glaciat$ regions t x =ms p]haps ! be/ di/+ui%+ m>k ( =m] glaciation4 ,! hummocky surface ( mora9al deposits is s *>act]i/ic t ! lakes ( ?is type are nev] v l>ge & are correspond+ly irregul> 9 outl9e4 ,!y h (t5 num]\s isl&s1 & _! banks are =m$ ( ! comb9ation ( rock fl\r & ice-worn mat]ials kn[n z till 7,fig4 #dci74 ,! smalle/ ( ! mora9al lakes are m]e kettles on ! m>g9al mora9e1 & ^! rapidly become replac$ by peat bogs4 ,9 contra/ ) pit lakes1 mora9al lakes lack ! /eep surr\nd+ slopes & ! encircl+ pla94 ,illu/ration3 ,,fig4 #dci4--;,diagrams to illu/rate ! *>act]i/ics ( mora9al lakes1 & a sample map ( su* lakes f ! glaciat$ region ( ,nor? ,am]ica4 ,pit lakes4--,! s-call$ pit lakes h _! orig9 9 cont95tal glaciation1 & are f\nd 9 gr\ps )9 broad pla9s ( glacial outwa% 7ma9ly s& & gravel71 :i* are = ?is reason describ$ z 8pitt$ pla9s0 7see p4 #cad74 ,^? areas :i* lay betwe5 neighbor+ lobes ( ! ice %eet 7 subject to p>ticul>ly heavy deposits ( outwa% mat]ial1 & are1 9 consequ5ce1 p>ticul>ly likely to be occupi$ by pit lakes4 ,z has be5 po9t$ out 9 an e>li] section1 ! wat] d]iv$ f surface melt+ )9 ! m>g9al portions ( a cont95tal glaci] desc5ds to ! bottom 9 ! crevasses & !reaft] fl[s 9 an ice tunnel "u ! same conditions z wat] fl[+ 9 a pipe4 ,hav+ 9 mo/ cases a consid]able head at ! out] m>g9 ( ! ice1 ?is wat] may rise & issue well above ! l[] ice lay]s & s cov] a portion ( ! ice m>g9 b5ea? s& & gravel 7,fig4 #ddj74 ,sep>at$ blocks1 (t5 ( massive proportions1 are ?us buri$ b5ea? nonconduct+ mat]ials by :i* !y are long protect$ f fur!r melt+4 ,ev5tually1 h[ev]1 ) ! approa* ( /ill mild] climates !y disappe>1 ?us caus+ ! ov]ly+ s& & gravel to desc5d & =m a pit ( /eep walls simil> to ! sawdu/ pits ov] melt$ ice blocks )9 our /oreh\ses4 ,illu/ration3 ,,fig4 #ddj4--;,diagram to %[ ! mann] ( =mation ( pit lakes4 ,pit lakes are ?us easily recogniz$ by _! occurr5ce usually 9 gr\ps )9 a pla9 ( glacial outwa% & by _! *>act]i/ic banks incl9$ at ! angle ( repose ( su* mat]ials 7,fig4 #dda74 ,illu/ration3 ,,fig4 #dda4--;,diagrams to illu/rate ! *>act]i/ics ( pit lakes & a sample map f ! glaciat$ region ( ,nor? ,am]ica4 ,gl9t or colk lakes4--,x has be5 f\nd to be true ( exi/+ cont95tal glaci]s t :]e _! mass has be5 held back by a m\nta9 wall1 _! curr5t at ! portals )9 ?is ramp>t becomes greatly accel]at$4 ,?\gh ! upp] lay]s ( ! glaci] 9 ! vic9ity may move =w>d ) a velocity ( b an in* p] day1 ! curr5t )9 ! outlet may be z mu* z sev5 hundr$ or a ?\s& times z great4 ,9 _m respects ^! conditions are simil> to ^? ab\t ! raceway ( a res]voir :]e ! ne>-by surface ( ! wat] is l[]$ by ! indraught ( ! outlet & ! curr5t 9 ! raceway is s accel]at$ t1 unless protect$1 ! bottom ( ! race is c>ri$ away & a bas9 excavat$ :i* ext5ds a %ort di/ance bo? above & bel[ ! position ( ! dam4 ,9 ,holl& su* bas9s holl[$ out b5ea? breaks 9 ! dykes are kn[n z colks4 ,bas9s :i* 7 excavat$ b5ea? ! glaci] outlets by a simil> process w\ld n be op5 to our inspection until aft] ! ice _h disappe>$ f ! region2 b x is mo/ significant t 9 ,sc&9avia1 :]e ! ,plei/oc5e cont95tal glaci]1 advanc+ we/w>d f ! ,baltic1 0 held 9 *eck by ! esc>pm5t at ! ,norwegian b\nd>y 7! gl9t71 lake bas9s h be5 excavat$ 9 h>d rock ^: walls %[ ! abrad+ & poli%+ :i* are *>act]i/ic ( glacial sculpture1 & ^: positions are su* t !y lie b5ea? ! =m] outlets p>tly above & 9 "p bel[ ! l9e ( ! esc>pm5t4 ,_! position 9 ref]5ce to ! ramp>t & to ! =m] outlets is br\ght out 9 ,fig4 #ddb4 ,! l>ge/ ( ! gl9t lakes ( ?is s]ies is ,tornetrsk 9 nor!rn ,lapl& 7see p4 #bgg & ,fig4 #ddc74 ,illu/ration3 ,,fig4 #ddb4--;,diagram to %[ ! mann] ( =mation ( gl9t or outlet lakes :]e ! cont95tal glaci] ( ,sc&9avia issu$ f ! ,baltic depression ?r\gh portals 9 its m\nta9 ramp>t4 ,illu/ration3 ,,fig4 #ddc4--,map %[+ a s]ies ( gl9t lakes :i* lie across ! int]national b\nd>y ( ,sw$5 & ,norway4 ,ice-dam lakes4--,:5ev] a cont95tal glaci]1 ei!r 9 advanc+ its front or 9 retir+1 lies across ! l9es ( dra9age ^u _! d[n/ream side1 wat] is imp\nd$ along ! ice front s z to =m ice-dam lakes4 ,su* lakes are f\nd to-day 9 ,gre5l& & 9 ! s\!rn ,&es1 & simil> bodies ( wat] ( f> great] size & importance came into exi/5ce 9 ,plei/oc5e times ea* "t t ! cont95tal glaci]s ( nor!rn ,nor? ,am]ica & ,europe advanc$ ^u or retir$ f suitably direct$ riv] sy/ems4 ,?us above ! ,baltic depression1 :5 ! ice front lay to ! ea/w>d ( ! ma9 wat]%$1 ea* ea/]ly slop+ valley 0 ob/ruct$ by ! ice & occupi$ by an ice-dam lake 7,fig4 #ddd71 ! bea*es ( :i* may all be trac$ to-day 7,fig4 #dde74 ,illu/ration3 ,,fig4 #ddd4--;,ice-dam lakes 79 black7 betwe5 ! front ( ! late ,plei/oc5e glaci] ( nor!rn ,europe & ! divide ne> ! ,norwegian b\nd>y 7aft] ,g4 de ,ge]74 ,"o side ( ea* ice-dam lake is =m$ by an ice cliff at ! glaci] front1 & if ! region is relatively flat1 ! rema9+ %ores are likely to be =m$ by a m>g9al mora9e :i* ! glaci] has ab&on$ 9 its retreat4 ,9 _! small] /ages1 !re=e1 ice-dam lakes on prairie c\ntry h ! =m ( a cresc5t1 :i* is ! m pron\nc$ because ! waves by _! attack ^u ! ice front flatt5 ! curvature ( its outl9e 7see ,fig4 #cfj1 p4 #ccj74 ,! life ( an ice-dam lake is begun & end$ 9 important *anges ( glaci] outl9e1 & aft] ! dra9+ ( lakes by ?is process ! l& %ores may be trac$ 9 bea*es1 & ! ice m>g9 by a wat]-laid mora9e ( l[ relief 7,fig4 #cei1 p4 #ccj74 ,a mu* small] b 9 _m respects simil> ice-dam lake is to-day to be se5 at ! side ( ! ,great ,alets* glaci]1 a m\nta9 glaci] ( ,switz]l&4 ,! travel] :o makes ! easy asc5t ( ! ,eggi%orn may look directly d[n ^u ?is cresc5t-%ap$ lake ) its ice cliff on ! glaci] side 7see ,fig4 #ddf74 ,illu/ration3 ,,fig4 #dde4--,wave-cut t]race at an elevation ( #agg4e met]s above sea on ! s\!rn slope ( ! nor!rn ,dala valley nor? ( ,bagg$al5 9 ,sw$54 ,to ! "r 9 ! =egr\nd is a peat bog 7aft] ,mun!74 ,illu/ration3 ,,fig4 #ddf4--,view ( ! ,mrjel5 ,lake at ! side ( ! ,great ,alets* glaci]1 se5 look+ directly d[n f ! summit ( ! ,eggi%orn 7aft] a photograph by ,i4 ,d4 ,scott74 ,glaci] lobe lakes4--,^u ! sites ( ! =m] lobes ( ! ,plei/oc5e glaci] ( ,nor? ,am]ica are f\nd ! bas9s ( ! ,laur5tian ,riv] sy/em1 ! l>ge/ fre%wat] lakes 9 ! _w4 ,!re has be5 mu* controv]sy conc]n+ ! mann] ( =mation ( ^! lakes1 b ! view :i* has seem$ to h ! l>ge/ foll[+ is t !y 7 excavat$ by ! erod+ action ( ! cont95tal glaci] ov] ! dra9age bas9s ( =m] riv]s4 ,x is b "o phase ( ! long controv]sy betwe5 oppos+ s*ools1 :i* h advocat$ on ! "o h& ! effici5cy ( glaci] ice z an erod+ ag5t1 & ^u ! o!r its suppos$ protection f ! wea!r+ processes4 ,! positions & ! outl9es ( ! sev]al lakes ( ! s]ies suffici5tly proclaim _! connection ) ! =m] glacial lobes1 & ! "n :i* we h adopt$ leaves ! exact mann] ( _! =mation a /ill op5 "q4 ,! recognition ( ! importance ( ! glacial anticyclone1 9 giv+ %ape to ! glaci] surface & 9 effect+ a transf] ( sn[ f ! c5tral to ! m>g9al portions1 has _h ! effect ( emphasiz+ ! relative importance ( erosion "u ! m>g9al & lobate portions4 ,?us ! importance ( ice lobes has be5 greatly acc5tuat$1 ?\gh ?is applies only to ! %ap+ ( ! bas9s & n 9 any important way to ! imp\nd+ ( ! pres5t wat]s4 ,! pres5t ,laur5tian ,lakes owe _! exi/5ce to ! elevation by successive uplifts ( ! c\ntry to ! nor?w>d & ea/w>d1 s9ce ! glaci] retir$ f ! lake region4 ,:5 ! ice front lay to ! nor?w>d ( ! ,ottawa ,riv]1 ! dis*>ge ( ! upp] lakes 0 by a *annel ?r\gh ,nipiss+ ,riv] & ,lake & !nce d[n ! ,ottawa ,riv] to a gulf 9 ! l[] ,/4 ,lawr5ce4 ,! uplift ( ! l& has _h ! effect ( rais+ a b>ri] :]e ! =m] outlet exi/$1 & div]t+ ! wat]s to a r\ndab\t *annel by way ( ,detroit & ,lake ,erie 7see ,fig4 #cfe1 p4 #cce74 ,illu/ration3 ,,fig4 #ddg4--;,diagrams to illu/rate ! arrangem5t & ! *>act]s ( rock-bas9 lakes1 toge!r ) a map ( su* lakes f ! ,bighorn ,m\nta9s 9 ,wyom+4 ,rock-bas9 lakes4--,! rev]s$ grades :i* develop 9 a valley deep5$ by m\nta9 glaci]s--! back-tilt$ treads ( ! cascade /airway 7see p4 #cgf7--;furni% a s]ies ( bas9s holl[$ 9 rock :i* are /rung along ! c\rse ( ! valley l pe>ls ^u a ?read1 or1 f> bett]1 l ! l>g] beads 9 a ros>y 7,fig4 #ddg74 ,?is *>act]i/ic arrangem5t acc\nts = ! "n 8,pat]no/] ,lakes0 :i* has sometimes be5 appli$ to !m 9 ,europe4 ,_! positions 9 s]ies )9 ,u-%ap$ m\nta9 valleys1 & _! rock %ores ) *>act]i/ically smoo!d & /riat$ surfaces1 make !m easy ( det]m9ation4 ,9 ! high] portions ( ! valley1 :]e ! treads ( ! cascade /airway are relatively n>r[1 su* lakes are (t5 approximately circul> 9 outl9e1 b 9 ! l[] levels & ^u wid] treads !y may be ribbon-l1 ?\gh lakes ( ?is type are to a l>ge ext5t replac$ 9 ! l[] levels by ! valley mora9e type or a comb9ation ( ! two4 ,illu/ration3 ,,fig4 #ddh4--;,convict ,lake1 a lake beh9d a mora9e dam )9 a glaciat$ valley ( ! ,si]ra ,nevadas1 ,cali=nia 7aft] a photograph by ,fairbanks74 ,valley mora9e lakes4--,! recessional mora9es :i* m>k ! halt+ /ations ( m\nta9 glaci]s1 :ile retir+ up _! valleys1 =m dams 9 ! lat] riv] & s produce a type ( lake :i* is 9 contra/ ) ! mora9al lakes :i* result f cont95tal glaciation4 ,!y may1 !re=e1 be di/+ui%$ by ! "n valley mora9e lakes4 ,_! positions on ! b$ ( a ,u-%ap$ m\nta9 valley1 & ! glacial mat]ials :i* compose ! dams1 are suffici5t = _! id5tification 7,fig4 #ddh74 ,mora9e ,lake & ,lake ,l\ise 9 ! ,canadian ,rockies are typical examples4 ,rock bas9 & valley mora9e lakes may occur 9 alt]nation or comb9$ 9 m\nta9 valleys4 ,illu/ration3 ,,fig4 #ddi4--,lake bas9s produc$ by successive slides f ! /eep walls ( a glaciat$ m\nta9 valley 7aft] ,russell74 ,l&slide lakes4--,! %e]-wall$ valleys :i* are c>v$ by m\nta9 glaci]s are too /eep to long reta9 _! p]p5dicul>ity :5 ! support ( ! glaci] has be5 remov$4 ,aid$ by ! ev] pres5t jo9t planes1 :i* admit wat] to ! rock1 !y succumb to fro/ action1 & fur!r give way 9 avalan*es :5ev] ! rock is ( suffici5tly por\s mat]ial to become saturat$ ) wat]4 ,l&slides sometimes occur successively until ! orig9al valley wall has be5 replac$ by a t]rac$ slope4 ,! treads ( ! /eps 9 ?is t]race h g5]ally a backw>d-slop+ grade1 s t bas9s are =m$ to be fill$ by relatively long & n>r[ lakes or by successions ( small pools 7,fig4 #ddi & plate #bc ,b74 ,illu/ration3 ,,fig4 #dej4--,lake ,g>da1 a bord] lake ^u ! site ( a pi$mont apron at ! m>g9 ( ! ,alp9e highl& 7aft] ,p5ck & ,brckn]74 ,:5 ! avalan*$ mat]ial is s dispos$ z to dam ! valley1 mu* l>g] lakes ( ?is type come into exi/5ce4 ,dur+ an e>?quake :i* occurr$ on ,janu>y #be1 #acdh1 !re 0 a l&slide )9 ! valley ( ! ,gail1 ,c>9?ia1 :i* de/roy$ sev5te5 villages & produc$ a lake :i* ev5 to-day is repres5t$ by a great m>%4 ,bord] lakes4--,:5ev] m\nta9 glaci]s pu% out _! fronts beyond ! bord]s ( ! m\nta9 range by :i* !y are n\ri%$1 !y spread ^u ! =el& 9 broad aprons ab\t :i* mora9ic accumulations are p>ticul>ly heavy4 ,?is elevation ( mora9al walls ab\t ! m>g9s ( ! aprons yields natural bas9s t are occupi$ by lakes s soon z ! glaci] retires its front )9 ! valley4 ,because su* lakes are f\nd at ! bord]s ( upl& di/ricts !y h be5 call$ bord] lakes4 ,! beautiful ,lakes ,con/ance1 ,luc]ne1 ,maggiore1 ,lugano1 ,como1 & ,g>da 7,fig4 #dej71 on ! bord]s ( ! ,alp9e highl&1 are all ( ?is type4 ,,plate #bc4 ,illu/ration3 ,a4 ,view ( ! ,am]ican ,fall at ,niag>a1 %[+ ! accumulation ( rocks b5ea? 7aft] ,grabau74 ,illu/ration3 ,b4 ,cry/al ,lake1 a l&slide lake 9 ,colorado4 7,photograph by ,h[l& ,bancr(t47 ,ox-b[ lakes4--,! cutt+ (f ( a me&] )9 ! flood pla9 ( a riv] yields a lake :i* is ( horse%oe 7ox-b[7 outl9e & lies g5]ally ) l[ banks )9 a pla9 compos$ ( riv] silt4 ,be=e sep>at+ f ! p>5t /ream ! me&] _h begun to silt up1 especially at ! ends4 ,ox-b[ lakes are1 h[ev]1 relatively deep ne> ! convex %ore & correspond+ly %all[ t[>d ! concave m>g9 7,fig4 #dea74 ,illu/ration3 ,,fig4 #dea4--;,diagrams to br+ out ! *>act]i/ics ( ox-b[ lakes1 toge!r ) a map ( su* lakes f ! flood pla9 ( ! ,arkansas ,riv]4 ,illu/ration3 ,,fig4 #deb4--;,diagrammatic section to illu/rate ! =mation ( sauc]-l bas9s betwe5 ! levees ( /reams fl[+ 9 a flood pla94 ,sauc] lakes4--,z we h le>n$1 a riv] me&]+ 9 its flood pla9 has banks :i* are high] ?an ! av]age level ( ! pla91 = ! reason t at flood "t ! ma9 curr5t ( ! /ream /ill p]si/s 9 ! *annel1 ?us all[+ ! burd5 ( s$im5t to be dropp$ 9 ! relatively slack wat] ^u its m>g94 ,because ( ^! natural embankm5ts or levees1 tribut>y /reams are (t5 compell$ to fl[ long di/ances 9 ne>ly p>allel direction be=e effect+ a junction4 ,betwe5 ! trunk /ream & its tribut>ies1 likewise b\nd$ by levees1 & betwe5 /reams & ! valley walls1 !re ?us exi/ l[ bas9s :i* are m or less sauc]-%ap$ 7,fig4 #deb74 ,at flood "t1 :5 ! levees are ov]fl[$ or crevass$1 wat] ent]s ^! depressions1 & an additional supply may be d]iv$ f ! walls ( ! valley4 ,good illu/rations ( su* lakes are furni%$ by ! flood pla9 ( ! =m] riv] ,w>r5 ne> ! banks ( ! pres5t ,m9nesota ,riv] 7,fig4 #dec74 ,illu/ration3 ,,fig4 #dec4--,sauc] lakes ^u ! b$ ( ! =m] riv] ,w>r5 7f ! ,m9neapolis %eet1 ,u4 ,s4 ,g4 ,s474 ,cresc5tic levee lakes4--,z we approa* ! delta ( a riv]1 ! size & importance ( ! levee increases1 & "h a new type ( levee lake may develop 9 s]ies 7,fig4 #ded74 ,at flood "t ! levee is brea*$ ne> ! po9t ( %>pe/ curvature on ! convex side 7,fig4 #ded a74 ,:5 ! wat]s are subsid+1 ! curr5t is kept away f ! old *annel by ! ris+ grade ( ! levee z well z by ! in]tia ( ! curr5t1 & an entrance to ! old *annel is fir/ f\nd bel[ ! next *ange 9 curvature ( ! me&]1 s9ce "h sc\r becomes effective 9 cutt+ ?r\gh ! levee4 ,! new *annel is ?us e/abli%$ 9 ! =m ( a loop inclos+ ! old "o1 & ! process ( levee build+ n[ erects a wall ab\t ! t]ritory newly acquir$ by ! me&]4 ,?is t]ritory has ! =m ( a cresc5t1 & :5 occupi$ by wat] produces a cresc5tic levee lake (t5 jo9$ to its neighbors 9 s]ies4 ,! ab&on$ *annel n[ clos$ at bo? ends by levees may be occupi$ by wat] to produce a subord9ate ribbon type ( curv+ tr5* 7,fig4 #ded b1 c74 ,! importance ( levees 9 ob/ruct+ dra9age to =m lakes is only beg9n+ to be appreciat$4 ,x has q rec5tly be5 %[n t :5 trunk /reams are greatly swoll5 & burd5$ ) s$im5t :ile fl[+ f a rec$+ cont95tal glaci]1 !y may build su* high levees z to aggrade _! tribut>y /reams above ! junctions1 ev5 produc+ rev]s$ grades & s imp\nd+ ! wat]s to =m ext5sive lakes4 ,dur+ ! 8ice age0 lakes ( ?is type 7 =m$ 9 ,ill9ois & ,k5tucky riv]s j above _! junctions ) ! ,ohio4 ,! old lake floor ) its ea/]n %ore l9e & its protrud+ isl&s is easily made out ^u ! new topographic maps ( ,k5tucky4 ,illu/ration3 ,,fig4 #ded4--,levee lakes develop$ conc5trically 9 s]ies )9 me&]s ( a /ream tribut>y to ! ,mississippi & fl[+ ^u its delta pla94 b & c are examples ( ! ribbon type ( levee lake due to occupation ( ! ab&on$ riv] *annel4 ,! l>g] numb] ( lakes1 ( :i* ,sip ,lake & ,texas ,lake are examples1 h ! =m ( cresc5ts & lie betwe5 ab&on$ levees 7f rec5t map ( ,u4 ,s4 ,g4 ,s474 ,raft lakes4--,)9 humid regions ! flood pla9s ( our l>g] riv]s are g5]ally =e/$1 & z ! riv] sw+s f side to side 9 its p]petual me&]+s1 ! timb] :i* gr[s ^u ! convex side ( ea* me&] is progressively und]m9$ by ! riv] & fell$ ^u its bank4 ,! pro/rate trees rema9 ^u ! banks dur+ ! l[ wat] ( ! summ] season1 to be ga!r$ up at ! "t ( flood 9 ! next spr+ season4 ,x is log jams ?us acquir$ :i* s g5]ally block ! ma9 *annel ( a riv] & turn ! curr5t across ! neck ( ! me&] :5 cut-(fs occur ) ! =mation ( ox-b[ lakes4 ,:5 ! mass ( timb] ?us ga!r$ up by ! riv] is excessive1 z1 = example1 )9 ! flood pla9 ( ! ,r$ ,riv] ( ,arkansas & ,l\isiana1 huge log rafts are produc$ :i* dam up ! riv] s effectively z to produce tempor>y lakes4 ,! imp\nd$ wat]s soon f9d an outlet ov] ! levee at "s po9t high] up ! riv]1 & ! wat]s fl[+ (f ?r\gh ! timb]$ bottom l&s1 o!r logs are caught by ! /&+ timb] z 9 a weir4 ,a second dam is ?us =m$ :i* is sep>at$ f ! initial "o by op5 wat]1 & 9 ?is way ! driftwood dam acquires enorm\s proportions z x gradually moves up ! riv]4 ,aft] a p]iod ( p]haps a c5tury or m1 ! l[] sections ( ! jam become decay$ & dislodg$ s z to float d[n ! riv]4 ,illu/ration3 ,,fig4 #dee4--,raft lakes along ! banks ( ! ,r$ ,riv] 9 ,arkansas & ,l\isiana at _! fulle/ record$ developm5t 7aft] ,a4 ,c4 ,veat*1 ,u4 ,s4 ,g4 ,s474 ,9 ! l[] ,r$ ,riv] a great raft ( alt]nat+ jams & op5 wat] rea*$ a l5g? ( ab\t "o hundr$ & sixty miles & mov$ up ! riv] at ! av]age rate ( some?+ less ?an a mile p] ye>4 ,)9 ! limits ( ! dam all tribut>y /reams 7 block$1 s t second>y lakes 7 =m$ 9 a d\ble fr+e ab\t ! ma9 riv] 7,fig4 #dee74 ,! great raft :i* =m$ "h 9 ! latt] "p ( ! fifte5? c5tury has n[ at ! beg9n+ ( ! tw5tie? be5 l>gely remov$ & measures h be5 adopt$ to prev5t its re-=mation4 ,illu/ration3 ,,fig4 #def4--,! ,swiss lakes ,?un & ,bri5z1 =m$ by deltas at ! junction ( /reams tribut>y to a /eep-wall$ valley4 ,side-delta lakes4--,x is *>act]i/ic ( riv] dra9age t ! tribut>y /reams ent] ! ma9 valley on /eep] gradi5ts ?an ! trunk /ream at ! po9t ( junction4 ,:]ev] ! diff]5ce 9 velocity ( ! two /reams at ! junction is l>ge1 & ! side /ream is *>g$ ) s$im5t1 a delta w be =m$ at ! m\? ( ! tribut>y /ream4 ,su* deltas pu% out f ! %ore & may ev5tually block ! ma9 *annel s z to =m a m or less sausage-%ap$ expansion ( ! riv]--a side-delta lake4 ,trav]se & ,big ,/one ,lakes 9 ! valley ( ! ,w>r5 ,riv] 9 ,m9nesota h be5 =m$ 9 ?is way 7,fig4 #ced1 p4 #cbf74 ,lakes ,?un & ,bri5z 9 ! ,swiss ,alps are ( simil> orig91 ! beautiful city ( ,int]lak5 be+ built ^u ! delta pla9 ov] ! valley ( ! e>li] riv] 7,fig4 #def74 ,! ,mississippi has simil>ly be5 exp&$ to =m ,lake ,pep9 above ! delta at ! m\? ( ! ,*ippewa ,riv]4 ,illu/ration3 ,,fig4 #deg4--;,delta lakes =m$ at ! m\? ( ! ,mississippi ?r\gh ! junction ( ! levees ( radiat+ di/ribut>ies ) ! %ore ( ! e/u>y 7aft] ,b]ghaus74 ,delta lakes4--,a some:at diff]5t type ( delta lake has be5 =m$ 9 ,l\isiana1 :]e ! 8fa!r ( wat]s0 dis*>ges into ! gulf4 ,"h ! v>i\s di/ribut>ies radiate f ! ma9 *annel to produce ! 8bird-foot0 delta type & ! toes 9 ?is foot by _! junction ) ! banks :i* outl9e ! anci5t e/u>y1 h sep>at$ 9 succession a s]ies ( bas9s t be=e 7 9 direct connection ) ! sea 7,fig4 #deg74 ,lake ,pont*>tra9 is ! l>ge/ ( ?is s]ies1 :ile ! s-call$ ,lake ,borgne is 9 process ( sep>ation4 ,:]e l>ge deltas pu% out f ! %ore into ! op5 sea1 ! levees :i* bord] ! individual di/ribut>ies are attack$ by ! waves & _! mat]ials are transport$ by ! %ore curr5ts & built into b>ri]s4 ,^! b>ri]s cut (f ! re-entrants betwe5 neighbor+ di/ribut>ies s z to produce lagoons or lakes 7,fig4 #deh74 ,illu/ration3 ,,fig4 #deh4--;,a type ( delta lakes =m$ by levees 9 "p de/roy$ & built into b>ri]s on ! m>g9 ( ! delta ( ! ,nile 7aft] ,supan74 ,a type ( delta lake1 :i* m resembles ! side-delta lake above describ$1 has =m$ at ! m\? ( ! ,colorado ,riv]1 :]e x ent]s ! ,gulf ( ,l[] ,cali=nia4 ,! ,imp]ial ,valley ly+ to ! nor? ( ?is delta is ! desiccat$ floor ( ! e>li] ,gulf ( ,l[] ,cali=nia :i* has be5 captur$ f ! sea by ! delta ( ! ,colorado4 ,! ramp>t ( m\nta9s1 by :i* ?is valley is surr\nd$1 has cut x (f f any wat] supply d]iv$ f cl\ds1 & its wat]s be+ no long] r5ew$ f ! sea1 ! region has pass$ ?r\gh a p]iod ( desiccation :i* has left ! ,salton ,s9k z ! only exi/+ remnant ( ! e>li] lagoon4 ,x w be rememb]$ t c>eless op]ations 9 div]t+ di/ribut>ies ( ! ,colorado rec5tly rev]s$ ?is process s t ! wat]s rose 9 ! valley1 & exp5sive em]g5cy op]ations 7 necess>y 9 ord] to aga9 turn ! wat]s ( ! ,colorado into _! accu/om$ *annels4 ,illu/ration3 ,,fig4 #dei4--;,diagrams to illu/rate ! *>act]i/ics ( b>ri] lakes1 ) an example f ! s\!rn coa/ ( ! ,isl& ( ,nantucket4 ,b>ri] lakes4--,! ,salton ,s9k illu/rates a type ( lake :i* is =m$ at ! bord] ( ! sea ?r\gh ! erection ( "s k9d ( b>ri] :i* captures a small area ( ! ocean's surface4 ,?\gh su* lakes may be prop]ly describ$ z /r& lakes1 x is usually at ! m\? ( a riv] t ! process becomes effective4 ,! common type ( b>ri] lakes is f\nd develop$ on mo/ ragg$ coa/ l9es :]e ! %ore curr5ts h =m$ fir/ b>s & lat] b>ri]s at ! m\?s ( ! e/u>ies 7,fig4 #dei74 ,su* embankm5ts are usually g5tly curv+ or cresc5t %ap$ & are compos$ ( s& or %+le :i* pres5ts a /eep l&w>d & a gradual seaw>d slope4 ,illu/ration3 ,,fig4 #dfj4--;,dune lakes on ! coa/ ( ,france 7aft] ,b]ghaus74 ,dune lakes4--,)9 ! n>r[ /rips ( %ore 9 :i* all ! f9e soil t c\ld be available = plant life has be5 wa%$ away by ! waves1 bea* s& is expos$ to ! direct action ( ! w9ds4 ,9 "t ( /orm ! s& is pick$ up & aft] drift+ 9 ! w9d is collect$ 9 long ridges p>allel to ! %ore4 ,con/antly travel+ along %ore1 ^! dunes block ! m\?s ( riv]s & ?us produce a s]ies ( lakes su* z are indicat$ 9 ,fig4 #dfj4 ,s9k lakes4--,ano!r class ( lakes are due ei!r directly or indirectly to ! "w ( und]gr\nd wat]s4 ,9 di/ricts :i* are und]la9 by lime/one1 ! surface wat] desc5d+ along ! jo9ts ( ! lime/one may wid5 ^! passageways ?r\gh solution ( ! rock & at l[] levels fl[ on ! floors ( cav]ns eat5 out by ! same process on b$d+ planes ( ! =mation4 ,at ! int]sections ( jo9ts1 m or less circul> %afts kn[n z 8swall[-holes0 g d[n to ! caves f ! surface4 ,locally1 also ! cav]n ro(s give way s z to *oke ! gall]ies ) rubble & leave a bas9 at ! surface :i* has an irregul> b g5]ally a m or less oval outl9e4 ,if suffici5tly clogg$ at ! bottom by f9] rock dbris1 ^! bas9s become occupi$ by small lakes :i* are kn[n z s9ks1 & con/itute "o ( ! be/ surface indications ( a lime/one c\ntry4 ,illu/ration3 ,,fig4 #dfa4--,s9k lakes 9 ,florida1 ) a s*ematic diagram to illu/rate ! mann] ( _! =mation 7map f ,u4 ,s4 ,g4 ,s474 ,k>/ lakes--polj54--,9 ! lime/one c\ntry to ! nor? & ea/ ( ! ,adriatic ,sea--! s-call$ ,k>/ region--!re are _m int]e/+ features :i* are directly traceable to ! solution ( ! c\ntry rock4 ,"h all ! surface wat] desc5ds 9 c]ta9 di/ricts along ! wid5$ jo9t planes s t ! dra9age is l>gely subt]ranean4 ,! s-call$ dol9es or s9ks ( v regul> & symmetrical =ms resembl+ deep b[ls cov] a l>ge "p ( ! surface4 ,! entire c\ntry is1 moreov]1 fault$ 9 ! mo/ intricate fa%ion into _m rift valleys4 ,! dra9age be+ s l>gely subt]ranean1 ^! d[n?r[n blocks ( cru/1 ! s-call$ polj51 become flood$ at c]ta9 seasons ( ! ye> :5 ! subt]ranean passages become *ok$ or are too small to c>ry away all ! wat]4 ,a seasonal lake ( ?is "* is ! ,zirknitz ,lake 7p4 #ahi74 ,playa lakes4--,x is ! law ( ! des]t t ! arid region be wall$ 9 by m\nta9s4 ,?is encircl+ ramp>t =ces ! cl\ds to rise1 & by robb+ !m ( _! moi/ure leaves ! des]t dry & b>r54 ,^? wat]s :i* fall ^u ! inn] m>g9 ( ! ranges dra9 t[>d ! int]ior ( ?is pan-l depression & are n return$ to ! sea--! des]t is )\t an outlet4 ,infrequ5t ?\gh !y be1 ! des]t ra9s are ( ! cl\dbur/ type & 9 ! hills develop torr5ts ^: wat]s1 em]g+ ^u ! des]t floor1 develop lakes 9 ! space ( a few m9utes or at mo/ h\rs4 ,9 ! hot & dry atmosph]e ! wat]s ( ^! %all[ bas9s may be suck$ up 9 ! space ( a few h\rs b reappe> 9 ! same bas9s at ! "t ( ! next succe$+ cl\dbur/4 ,su* ephem]al lakes are kn[n z playas4 ,sal9es4--,des]t lakes m favor$ 9 _! supply ( wat] may be relatively long liv$ & p]si/ = p]iods measur$ 9 ye>s or c5turies4 ,su* lakes are1 h[ev]1 extremely s5sitive to climatic *anges 7see p4 #aih74 ,= ! reason t !y h no outlet ! wat]s ( des]t lakes become salt ?r\gh cont9u$ evaporation4 ,!y are1 !re=e1 spok5 ( z sal9es4 ,lake ,bonneville1 s long z x dis*>g$ its wat]s ov] ! sill ( ! ,r$ ,rock ,pass1 mu/ h rema9$ fre%2 b :5 ! level ( its wat]s _h fall5 bel[ ?is outlet1 its wat]s became salt & ! cont5t increas$ z ! volume dim9i%$4 ,! %all[ bas9s ^u ! floors ( des]t lakes may h come into exi/5ce 9 v>i\s ways2 b x w\ld appe> t ! irregul> removal ( ! soil by ! w9ds1 modifi$ z ?is is by diff]5ces 9 composition ( ! rock mat]ials & by vegetable gr[?1 & ! deposition ( s& by ! same ag5t1 are by f> ! mo/ important4 ,_m ( ! types ( tectonic & volcanic lakes :i* h be5 describ$ are *>act]i/ic ( humid & arid regions alike4 ,alluvial-dam lakes4--,)9 ! m\nta9s ^u ! des]t bord]s1 ! alluvial fans :i* =m at ! m\?s ( valleys1 because ( ! *>act]i/ic cl\dbur/1 sometimes ob/ruct a ma9 valley at ! junction ) its tribut>ies4 ,by ?is process ! wat]s ( ! ma9 riv] are imp\nd$ 9 ess5tially ! same mann] z are ! riv]s ( humid regions by ! deltas ( _! tribut>ies4 ,rsum4--,! types ( lakes :i* we h n[ consid]$ are arrang$ bel[ 9 tabul> =m s z to %[ _! relation%ip to important geological processes4 ,:ile n complete1 ! li/ includes ! m important classes1 z well z o!rs :i*1 :ile n ( common occurr5ce1 are yet ( int]e/ 9 giv+ fur!r illu/ration to ! processes :i* h be5 treat$ 9 e>li] *apt]s4 ,by giv+ c>eful att5tion to crit]ia :i* h be5 above sugge/$1 x %\ld be possible 9 ! great] numb] ( in/ances at lea/ to det]m9e :e!r any lake :i* is visit$ has _h its orig9 9 "o or ano!r ( ! processes describ$4 ,,classification ,,( ,,lakes ,tectonic ,lakes ,volcanic ,lakes ,newl& lakes ,crat] lakes ,bas9-range lakes ,c\le lakes ,rift-valley lakes ,e>?quake lakes ,cont95tal ,glaciation ,lakes ,m\nta9 ,glaciation ,lakes ,mora9al lakes ,rock-bas9 lakes ,pit lakes ,valley mora9e lakes ,gl9t or colk lakes ,l&slide lakes ,ice-dam lakes ,bord] lakes ,glaci]-lobe lakes ,riv] ,lakes ,/r& ,lakes ,ox-b[ lakes ,b>ri] lakes ,sauc] lakes ,dune lakes ,cresc5tic levee lakes ,raft lakes ,side-delta lakes ,delta lakes ,gr\nd ,wat] ,lakes ,des]t ,lakes ,s9k lakes ,playa lakes ,k>/ lakes--polj5 ,sal9es ,alluvial dam lakes4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxix ,g5]al3-- ,i4 ,c4 ,,russell4 ,lakes ( ,nor? ,am]ica4 ,bo/on1 #ahie1 pp4 #abe1 pls4 #bc4 ,a4 ,p4 ,,brigham4 ,lakes1 ,a ,/udy = ,tea*]s1 ,j\r4 ,s*4 ,geogr41 vol4 #a1 #ahig1 pp4 #fe-gb4 ,n4 ,m4 ,,f5neman4 ,! ,lakes ( ,s\!a/]n ,wiscons91 ,bul4 #h1 ,wis4 ,geol4 & ,nat4 ,hi/4 ,surv41 #aijb 7,rev4 ,ed41 #aiaj71 pp4 #ahh1 pls4 #cg4 ,a4 ,,delebecque4 ,les ,lacs ,franais 7) ,atlas74 ,p>is1 #ahih4 7,"w cr[n$ by ! ,society ( ,geology ( ,p>is47 ,h4 ,r4 ,,mill4 ,ba?ymetrical ,survey ( ! ,engli% ,lakes1 ,geogr4 ,j\r41 vol4 #f1 #ahie1 pp4 #df-gc1 #ace-aff4 ,a4 ,,supan4 ,grundzge d] ,physis*5 ,erdkunde4 ,leipzig1 #ahif1 pp4 #eca-edh4 ,h4 ,,b]ghaus4 ,atlas d] ,hydrographie4 ,go?a1 #ahia1 pl4 #c4 ,r4 ,d4 ,,salisbury4 ,physiography4 #aijg1 pp4 #bib-cbg4 ,,*>les ,,rabot4 ,revue de limnologie1 ,la ,gographie1 ,vol4 #d1 #aija1 pp4 #aaj-aai1 #agb1 #ahi4 ,i4 ,c4 ,,russell4 ,a ,geological ,reconnaissance 9 ,s\!rn ,oregon1 #d? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahhd1 pp4 #ddb-ddg4 7,bas9 range lakes47 ,,ed4 ,,suess4 ,! ,face ( ! ,e>?1 vol4 #d1 #aiji1 pp4 #bfh-bhf4 7,rift valley lakes47 ,j4 ,s4 ,,dill]4 ,crat] ,lake1 ,nat4 ,geogr4 ,mag41 vol4 #h1 #ahig1 pp4 #cc-dh1 pl4 #a2 ,geology ( ,lass5 ,peak ,quadrangle1 ,cali=nia1 ,geol4 ,fol4 #ae1 ,u4 ,s4 ,geol4 ,surv41 #ahie4 7,c\le lakes47 ,n4 ,m4 ,,f5neman4 ,lakes ( ,s\!a/]n ,wiscons91 l4c41 pp4 #d-f4 7,pit lakes47 ,,ed4 ,,suess4 ,! ,face ( ! ,e>?1 vol4 #b1 #aijf1 pp4 #cdj-cdf1 pl4 #g4 7,gl9t lakes47 ,i4 ,c4 ,,russell4 ,a ,prelim9>y ,pap] on ! ,geology ( ! ,cascade ,m\nta9s 9 ,nor!rn ,wa%+ton1 #bj? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv4 ,pt4 ii1 #aijj1 pl4 #ad4 7,view ( a rock-bas9 lake47 ,e4 ,w4 ,,%aw4 ,prelim9>y ,/atem5t conc]n+ a ,new ,sy/em ( ,quat]n>y ,lakes 9 ! ,mississippi ,bas91 ,j\r4 ,geol41 #aiaa1 pp4 #dha-dia4 7,new type ( levee lakes47 ,a4 ,c4 ,,veat*4 ,=mation & ,de/ruction ( ! ,lakes ( ! ,r$ ,riv] ,valley1 ,pr(4 ,pap4 ,no4 #df1 ,u4 ,s4 ,geol4 ,surv41 pp4 #fj-fb1 pls4 #bi-cc4 7,raft lakes47 ,m4 ,,neumey]4 ,erdges*i*te1 vol4 #a1 pp4 #eie-eif4 7,polj547 ,,*apt] ,,xxx ,,! ,,ephem]al ,,exi/5ce ,,( ,,lakes ,lakes z settl+ bas9s4--,( all ! processes :i* conspire to blot out ! lakes ) :i* our nor!rn l&scapes are dott$1 ! "o ( greate/ importance is 9 mo/ cases a process ( fill+ by ! s$im5ts br\ght 9 by tribut>y /reams4 ,! c>ry+ ( s$im5t 9 susp5sion dep5ds1 z we "k1 ^u ! velocity ( ! curr5t1 & z ?is is *eck$ :]e x rea*es ! lake m>g91 all co>s] mat]ial is at once deposit$ to =m a delta1 :ile ! f9] s$im5ts are held long] 9 susp5sion & f9ally settle 9 ?9 lay]s ov] ! entire bottom ( ! lake4 ,clay deposits surr\nd$ by co>s] s$im5ts are ?us *>act]i/ic ( fill$ lake bas9s4 ,illu/ration3 ,,fig4 #dfb4--,map ( ! ,arve & ! upp] ,rhone to %[ ! importance ( ,lake ,g5eva z a settl+ bas9 ( ! l>g] /ream4 ,h[ wat]s are cl>ifi$ by _! passage ?r\gh a lake is indicat$ by a comp>ison ( a riv] sy/em su* z ! ,/4 ,lawr5ce1 ) a riv] l ! ,miss\ri & ,mississippi4 ,n only are ! l[] /ret*es ( ! ,/4 ,lawr5ce 9 /rik+ contra/ ) ! muddy floods ( ! ,miss\ri & ,mississippi2 b ! delta1 :i* is s rem>kable a feature 9 ! ,mississippi1 has no c\nt]p>t 9 ! nor!rn riv]4 ,! mo/ notewor?y examples ( settl+ are1 h[ev]1 furni%$ by ! lakes ( ,switz]l&1 = ! reason t ,,swiss riv]s are heavily *>g$ ) rock fl\r produc$ b5ea? ! num]\s glaci]s at ! valley heads1 &1 fur!r1 because ^! riv]s desc5d ) turbul5t curr5ts to ne> ! bord]s ( ! l>g] lakes4 ,to look out ^u ! murky wat]s ( ! upp] ,rhone1 :]e !y ent] ,lake ,g5eva ne> ,vill5euve1 & !n to wat* ! flood ( cry/al wat] :i* issues f ! lake & passes "u ! bridge at ,g5eva1 is an object lesson :i* no travel+ /ud5t %\ld miss 7,fig4 #dfb74 ,yet ev5 m in/ructive is a visit to ! ,bois de la ,btie at ! junction ( ?is cle> /ream ) ! ,arve1 a half h\r's walk only bel[ ,g5eva4 ,! wat]s ( ! ,arve h come on a /eep desc5t directly f ! glaci]s ( ! ,mont ,blanc di/rict1 & z !y meet ! cle>$ wat]s ( ! ,rhone1 !y fl[ beside !m d[n ! common valley )\t m+l+4 ,dull & opaque1 ! ,arve wat]s c be disc]n$ = a long di/ance z a :ite belt aga9/ ! left bank ( ! riv]1 %>ply def9$ aga9/ ! blue reflect+ surface ( ! ,rhone wat]s 7,fig4 #dfc74 ,^u ! banks ( ! ,arve1 j above its junction1 a cem5t manufactory has be5 e/abli%$ to utilize ! clays :i* are "h deposit$4 ,illu/ration3 ,,fig4 #dfc4--,view look+ up/ream across ! opaque wat]s ( ! ,arve to ! cle> reflect+ surface ( ! ,rhone4 ,to ! "r across ! ,arve is se5 ! cem5t works = recov]+ ! ,arve s$im5ts4 ,:]ev] lakes are conta9$ 9 long & n>r[ valleys1 ! great] "p ( ! tribut>y dra9age ent]s at ! upp] end1 & ! delta :i* !re =ms ext5ds f bank to bank4 ,z x cont9ues to advance into ! lake1 ! e>li] wat] bas9 is gradually trans=m$ into a level pla9 ( delta deposit1 a feature s common z to be des]v+ ( a special "n4 ,! ,scotti% lo*s1 :i* are lakes ( ?is type1 are ea* ext5d$ 9 a long] or %ort] delta pla9 describ$ z a /ra?1 & ?is local t]m may well be giv5 a g5]al application 7frontispiece74 ,! city ( ,i?aca1 ! seat ( ,cornell ,univ]sity1 is built ^u a /ra? at ! head ( ,lake ,cayuga1 & numb]less ,scotti% & ,swiss hamlets h be5 locat$ ^u su* f]tile pla9s 7,fig4 #dfd74 ,illu/ration3 ,,fig4 #dfd4--,! village ( ,pos*iavo 9 ea/]n ,switz]l&1 built ^u a /ra? at ! head ( ,lake ,pos*iavo4 ,draw+ (f ( wat] by erosion ( outlet4--,next 9 importance to ! fill+ up ( lake bas9s z a factor 9 _! e>ly ext9ction is ! cutt+ d[n ( _! *annels ( outfl[4 ,:5ev] ! walls ( ! outlet are cut 9 rock1 ?is dra9+ process is apt to be sl[1 = ! reason t ! outlet /ream is ( filt]$ wat] & s lacks ! necess>y cutt+ tools4 ,by f> ! l>g] numb] ( lakes are1 h[ev]1 held back by dams ( loose drift deposits laid d[n by ! e>li] cont95tal glaci]s2 & s ! v cl>ity ( ! wat] promotes ! erosion ( ! outlet by all[+ ! /ream's full burd5 ( s$im5t to be lift$ & !n remov$ f ! *annel4 ,! pull+ 9 ( headl&s & ! cutt+ (f ( bays4--,! removal ( project+ headl&s by wave action1 ?\gh x increases ! area ( ! lake1 yet x decreases directly ! volume ( lake wat] ?r\gh =mation ( ! built t]race1 & indirectly 9 f> l>g] measure ?r\gh ! trans=mation ( bays into quiet lagoons )9 :i* ! ext+ui%+ process ( peat gr[? is set 9 op]ation4 ,lake ext9ction by peat gr[?4--,! fir/ condition = ! gr[? ( lake vegetation is quiet wat]4 ,)9 small lakes1 su* z ! kettle bas9s ^u mora9es1 aquatic vegetation develops rapidly1 & bogs ( peat might almo/ be includ$ among ! mo/ important di/+ui%+ m>ks ( a glaciat$ c\ntry4 ,)9 l>g] lakes x is only aft] b>ri] bea*es h be5 ?r[n across ! m\?s ( ! bays to =m natural breakwat]s = ! waves t ?is process ( lake ext9ction by peat gr[? c become effective4 ,illu/ration3 ,,fig4 #dfe4--,view ( ! float+ bog & surr\nd+ zones ( vegetation 9 a small glacial lake ( ! ,yell[/one ,national ,p>k 7aft] a photograph by ,fairbanks74 ,_m errone\s notions are /ill held conc]n+ ! prime importance ( sphagnum 9 peat =mation1 ow+ to ! peculi> local conditions "u :i* ! e>ly /udies 7 made4 ,)9 ! glaciat$ di/ricts ( ! ,unit$ ,/ates1 ! =mation ( peat involves ! successive gr[?s ( a numb] ( zones ( vegetation & ! =mation ( a float+ bog :i* advances into ! lake f ! %ores1 foll[$ 9 turn by belts ( l[ %rubs1 tam>acks1 & la/ly decidu\s trees 7,fig4 #dfe74 ,9 mo/ cases ! fir/ plants to develop 9 a quiet lake are ! wat] lilies1 ?\gh ^! are sometimes prec$$ by *>a & float+ bladd]wort4 ,next beh9d ! wat] lilies come ! s$ges1 :i* =m a mat ( float+ bog by _! grasslike /ems s9k+ d[n 9 ! wat] & be+ !re int]wov5 ) ! rhizomes bel[4 ,?is mat ( s$ge is (t5 s firm t cattle may advance ^u x to ! wat]'s edge1 b x is sep>at$ by a lay] ( wat] f ! b$ ( gr[+ peat at ! bottom ( ! lake 7,fig4 #dff74 ,?is b$ ( peat appe>s to gr[ upw>d t[>d ! surface & become jo9$ to ! %ore end ( ! float+ bog by decay+ vegetation :i* is dropp$ f ! bottom ( ! mat above4 ,illu/ration3 ,,fig4 #dff4--;,diagram to %[ h[ small lakes are trans=m$ into peat bogs 7aft] ,c4 ,a4 ,davis74 ,9 ord] beh9d ! float+ bog come ! advanc$ plants ( ! conif] gr\p1 ) sphagnum & l[ %rub "h ^u a peat base ext5d+ to ! lake bottom4 ,beh9d ! belt ( %rubs arise ! tam>acks & spruces1 & la/ly1 t[>d ! %ore1 come ! decidu\s trees & especially popl>s1 maples1 & m>g9al will[s4 ,^u ! m>g9 ( ! bas9 !re is usually a l[ tr5*1 or 8fosse01 fill$ ) wat] dur+ wet seasons1 z a result1 no d\bt1 ( seasonal inwa% t does n rea* ! residual lake t[>d ! c5t] ( ! bas94 ,ext9ction ( lakes 9 des]t regions4--,9 arid regions !re are special causes ( lake ext9ction4 ,?us ! bl[+ 9 ( s& & du/ c>ri$ = long di/ances 9 ! air1 a by no means negligible factor ev5 9 humid regions1 "h assumes l>ge importance4 ,! n[ expos$ bas9s ( ext9ct des]t lakes af=d ! evid5ce1 h[ev]1 ( an ev5 great] factor ( ext9ction1 9 climatic *ange4 ,! cl\ds1 :i* at "o "t f\nd _! way into ! dra9age bas9 ( a lake1 may lat] ?r\gh ! rise ( a m\nta9 b>ri] be cut (f1 & s ) r$uc$ wat] supply a p]iod ( lake desiccation is begun4 ,:51 9 ?is process ( dry+ up1 ! lake level has fall5 bel[ t ( ! outlet1 ! sal9e cont5t ( ! wat]s beg9s to increase1 & lat] a /age is rea*$1 z 9 ,great ,salt ,lake1 :5 ! sodium salts are precipitat$4 ,:5 ! lake has become ext9ct1 ^! deposits rema9 z a witness to ! *ang$ climatic condition4 ,! rle ( lakes 9 ! economy ( nature4--,x is natural1 9 consid]+ ! ext9ction ( lakes1 to give "s att5tion to ! rle :i* !y play 9 ! economy ( nature4 ,t lakes filt] ! wat] ( riv]s1 & prev5t ! =mation ( important delta deposits1 has already be5 notic$4 ,a curi\s exception to ?is g5]al rule is furni%$ by ! great delta at ! head ( ,lake ,/4 ,clair1 j bel[ ! outlet ( ,lake ,huron4 ,?is anomaly is1 h[ev]1 expla9$ by ! peculi> curr5ts ( ,lake ,huron1 :i* are s direct$ z to sweep ! bea* s& into ! swift curr5t ( ! outlet1 to be deposit$ 9 ! quiet wat]s ( ,lake ,/4 ,clair 7,fig4 #dfg74 ,illu/ration3 ,,fig4 #dfg4--,map to %[ anomal\s position ( ! delta 9 ,lake ,/4 ,clair1 due to ! peculi> curr5ts 9 ,lake ,huron 7aft] maps by ,cole74 ,z regulators ( ! fl[ ( riv]s1 lakes p]=m an important function4 ,su* disa/r\s floods z are *>act]i/ic ( ! spr+ season )9 ! bas9 ( ! l[] ,mississippi c\ld n occur 9 ! l[] ,/4 ,lawr5ce1 = ! reason t ! great bas9s ( ! lakes s]ve z di/ribut+ res]voirs4 ,! annual floods1 ^u :i* ! agriculture ( ,egypt dep5ds1 are expla9$ by ! flood wat]s f ! high m\nta9s ( ,abyss9ia ent]+ ! ,nile bel[ ! lakes ( its upp] bas94 ,9 "o fur!r respect l>ge inl& bodies ( wat] h an important function z regulators4 ,x is ! prop]ty ( wat] to respond b sl[ly to ! v>iations 9 ! quantity ( heat :i* rea*es ! e>?'s surface f ! sun4 ,a l>g] quantity ( heat mu/ be add$ to or ab/ract$ f a body ( wat]1 9 ord] to *ange its temp]ature by "o degree1 ?an w\ld be requir$ = a l *ange 9 ! same bulk ( e>? or rock4 ,?us bodies ( wat] by m sl[ly acquir+ ! summ]'s heat ret>d ! com+ spr+1 & by /or+ up ?is en]gy & c>ry+ x ov] into ! autumn ! w>m season is prolong$ & e>ly fro/s prev5t$4 ,! fruit belts ab\t ! l[] ,great ,lakes are ?us dep5d5t ^u ?is regulat+ prop]ty ( ! lake wat]s4 ,! discom=t ( ! long spr+ ( raw wea!r is ?us comp5sat$ by an unusually salubri\s h>ve/ season4 ,ice ramp>ts on lake %ores4--,small ridges kn[n z ice ramp>ts are =m$ ^u lake %ores by ! action ( lake ice1 ?\gh subject to s _m qualify+ conditions t ! range ( _! occurr5ce is some:at limit$4 ,)9 di/ricts :]e a w9t] ice cov] ( "s ?ickness is =m$1 ! %ores ( lakes are apt to pres5t ridges ( b[ld]s p>allel to & ne> ! wat]'s edge1 & su* lakes h sometimes become kn[n z 8wall lakes0 7,fig4 #dfh74 ,illu/ration3 ,,fig4 #dfh4--;,a b[ld] wall ^u ! %ore ( a small lake 9 ! ,adirondacks ( ,new ,york4 ,9 _m cases ^! small ridges h be5 =m$ at ! "t ( ! spr+ 8break up0 ( ! ice2 = ! ice cov]1 :5 once loos5$1 is drift$ 9 great rafts fir/ aga9/ "o %ore1 & lat]1 ) a *ange ( w9d direction1 aga9/ ano!r4 ,"u ! impact ( su* heavy rafts1 ! half-subm]g$ b[ld]s ne> ! %ore are =c$ up ! bea* until !y lie 9 a ridge or b[ld] wall4 ,at o!r times su* b[ld] walls1 & f> m int]e/+ ridges z well1 result f a k9d ( ice %ove indep5d5t ( ! w9d1 b caus$ by expansion )9 ! ice itself dur+ a sudd5 rise ( temp]ature ( ! surr\nd+ air4 ,su* ice ramp>ts require = _! explanation a consid]ation ( ! sequ5ce ( ev5ts f ! "t ! ice cov] closes ! lakes4 ,illu/ration3 ,,fig4 #dfi4--;,diagrams to %[ ! effect ( ice %ove 9 produc+ ice ramp>ts ^u ! %ores ( lakes 7aft] ,buckley ) a slight modification74 ,! fir/ lake ice ( e>ly w9t] =ms 9 mo/ cases ) air temp]atures a few degrees only bel[ ! freez+ po9t ( ! wat]4 ,:5 lat] a sev]e 8cold wave0 arrives1 ! ice cov] is contract$ & becomes too small = ! lake surface4 ,to ?is contraction x yields & op5s cracks up :i* ! wat] rises1 & 9 ! prevail+ l[ temp]ature ?is wat] is quickly froz5 & ! lake cov] aga9 made complete4 ,skat]s are famili> ) ! op5+ ( ^! cracks & ! l\d 8ro>+0 :i* accompanies x on cold morn+s1 ! %>p skate runn]s sometimes />t+ a crack 9 ! /ra9$ ice1 z does a light scrat* ^u glass t is 9 a simil> /ra9$ condition4 ,illu/ration3 ,,fig4 #dgj4--,v>i\s =ms ( ice ramp>ts 7aft] ,buckley74 ,! orig9al ice cov] ( ! lake1 :i* 0 =m$ at ne>-freez+ temp]atures1 has n[ receiv$ a numb] ( ins]t$ w$ges ( new ice at a "t :5 its contract$ volume has made ?is possible4 ,if n[ a 8w>m wave0 succe$s to ! 8cold wave0 9 ! air1 ! ice cov] exp&s at a rate correspond+ to its rate ( contraction1 s t a /rong pressure is ex]t$ aga9/ ! %ore 7,fig4 #dfi74 ,slid+ up ! slop+ surface ( ! cut & built t]race1 ! =ce ( ?is %ove may be deflect$ upw>d aga9/ ! cliff1 & if ?is is ( loose mat]ials1 ! effect may be to ram b[ld]s into ! bank1 to pu% up ramp>ts or ridges1 to ov]turn trees1 etc4 7,fig4 #dgj74 ,9 m>% l& ! froz5 surface lay] may slide ov] its unfroz5 base & be =c$ up into brok5 folds 7l[] diagram ( ,figs4 #dfi & #dgj74 ,illu/ration3 ,,fig4 #dga4--,map ( ,lake ,m5dota at ,madison1 ,wiscons91 %[+ ! position ( ! ridge :i* =ms f ice expansion1 & ! ice ramp>ts ab\t ! %ores ( ! bays 7bas$ on ,buckley's map74 ,9 ord] t ice ramp>ts may be =m$1 x is necess>y t ! w9t] climate ( ! di/rict be sev]e & *>act]iz$ by alt]nat+ cold & w>m waves1 involv+ consid]able range ( air temp]ature bel[ ! freez+ po9t4 ,if ! lake is small1 ! pu% ( ! ice w be ?r\gh s small a di/ance z n to yield appreciable ramp>ts4 ,if1 on ! o!r h&1 ! lake is too l>ge1 ! ice cov] is n rigid en\gh to transmit ! pu% to ! di/ant %ore1 b1 l a long beam employ$ 9 ! same mann] to transmit a compressive /ress1 x is b5t out ( a /raight l9e & lat] brok54 ,?us 9 a broad lake1 ) ! com+ ( a 8w>m wave01 ! ice cov] op5s 9 a crack f %ore to %ore & f9ds relief f ! /ress by pu%+ up a ridge above ! crack4 ,on su* lakes ice ramp>ts are f\nd only ab\t ! %ores ( bays ^: expanse does n greatly exce$ a mile 7,fig4 #dga74 ,:5 !re is heavy sn[fall1 ice ramp>ts ei!r d n =m or are ( small] dim5sions1 probably 9 "p because ! ice is blanket$ by ! sn[ & s prev5t$ f sudd5 elevation ( temp]ature dur+ ! 8w>m wave01 b ev5 m because ! ice cov] is s5sibly b[$ d[n "u its load & s r5d]$ incompet5t to transmit ! develop$ /resses to ! %ores4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxx ,lake ext9ction by peat gr[?3 ,c4 ,a4 ,,davis4 ,peat1 ,essays on its ,orig91 ,uses1 & ,di/ribution 9 ,mi*igan1 ,ann4 ,rept4 ,mi*4 ,geol4 ,surv4 = #aijf1 #aijg1 pp4 #aje-ahb2 ,peat ,deposits z ,geological ,records1 #aj? ,rept4 ,mi*4 ,acad4 ,sci41 #aijh1 pp4 #ajg-aab4 ,g4 ,p4 ,,burns4 ,bog ,/udies4 ,ann ,arbor1 #aijf1 pp4 #ac4 ,ice ramp>ts3 ,c4 ,h4 ,,hit*cock4 ,%ore ,ramp>ts 9 ,v]mont1 ,proc4 ,am4 ,assoc4 ,adv4 ,sci41 vol4 #ac1 #ahfi1 pp4 #cce-ccg4 ,g4 ,k4 ,,gilb]t4 ,lake ,bonneville1 ,mon4 #a1 ,u4 ,s4 ,geol4 ,surv41 #ahij1 pp4 #ga-gb4 ,e4 ,r4 ,,buckley4 ,ice ,ramp>ts1 ,trans4 ,wis4 ,acad4 ,sci41 etc41 vol4 #ac1 #aijj1 pp4 #ada-afb1 pls4 #a-ah4 ,,william ,h4 ,,hobbs4 ,requisite ,conditions = ! ,=mation ( ,ice ,ramp>ts1 ,j\r4 ,geol41 vol4 #ai1 #aiaa1 pp4 #aeg-afj4 ,,*apt] ,,xxxi ,,! ,,orig9 ,,& ,,! ,,=ms ,,( ,,m\nta9s ,a m\nta9 def9$4--,z ord9>ily und]/ood1 m\nta9s are elevations ^u ! e>?'s surface :i* rise above ! g5]al level ( ! c\ntry4 ,_! summits ne$ n be at great heights above ! sea1 b x is ess5tial t !y project above ! av]age level ( ! surr\nd+ c\ntry by at lea/ a qu>t] ( a mile4 ,l[] elevations are describ$ z hills4 ,on ! o!r h&1 ! elevation ( a plateau l ! 8,high ,pla9s0 ( ! we/]n ,unit$ ,/ates may be z mu* z a mile1 b ! va/ expanse ( ne>ly level surface precludes ! use ( ! t]m 8m\nta940 ,! ^w is ?us appli$ to a feature ( ! e>? & n m]ely to an elevat$ tract4 ,9 a collective s5se1 ?\gh m (t5 9 ! plural =m1 ! t]m is prop]ly appli$ to gr\ps ( simil> features :i* h a common orig9 9 local uplift ( ! l&4 ,! orig9 ( m\nta9s us$ 9 ?is s5se ( m\nta9 complexes is ?us connect$ ) "s ess5tially local uplift ( ! e>?'s surface4 ,?is may take place by ! processes ( fold+ & sup]9cumb5t fault displacem5t1 by volcanic extravasations or ejections1 or by a deep] seat$ & ess5tially hydro/atic elevation ( rock b$s ov] molt5 rock mat]ial4 ,! exi/+ =ms ( m\nta9s1 z we are to see1 are l>gely %ap$ by ! erosional processes :i* are set 9 op]ation by ! uplift itself1 ?\gh (t5 complet$ long subsequ5t to x4 ,! fe/oons ( m\nta9 arcs4--,f our e>lie/ /udies ( s*ool geographies1 we h become famili> ) ! arrangem5t ( ! m important m\nta9s 9 long *a9s or sy/ems4 ,comp>atively few p]sons h giv5 any fur!r att5tion to ! arrangem5t ( ! *a9s1 ?\gh ov] l>ge areas ( ! e>?'s surface ! di/ribution ( m\nta9 ranges is deeply significant4 ,! map ( ,asia 9 p>ticul> pres5ts a s]ies ( great sweep+ arcs or cresc5ts :i* are gr\p$ z ?\gh hung ^u ! map 9 fe/oons ) knots or v]texes to sep>ate neighbor+ gr\ps 7,fig4 #dgd1 p4 #dch1 & ,fig4 #dgb74 ,illu/ration3 ,,fig4 #dgb4--,! great multiple m\nta9 arc ( ,sewe/an1 ,briti% ,india 7aft] de ,sa9t ,m>t9 & ,s*rad]74 ,! significance ( ^! m\nta9 gr\p+s 9 ! evolution ( ! e>?'s surface has be5 po9t$ out by ! great ,vi5nese geologi/ ,suess1 to :om we are indebt$ = focus+ ^u ! plan ( ! e>? an am\nt ( att5tion :i* be=e _h be5 l>gely giv5 to ! prep>ation ( hypo!tical sections ( /rata :i* 7 l>gely buri$ f sight b5ea? ! e>?'s surface4 ,broadly speak+1 ! m\nta9 arcs may be said to be gr\p$ ab\t ^? %ields ( old] rock :i* geological /udies h %[n to be ! olde/ l& masses ^u ! globe4 ,)9 ! nor!rn hemisph]e ^! orig9al cont95ts are repres5t$ by ! areas ( cry/all9e rock c5t]$ ov] ,hudson ,bay1 ! ,baltic ,sea1 & an area 9 nor!a/]n ,sib]ia kn[n to geologi/s z ,ang>a ,l&4 ,9 our /udy ( ! figure ( ! e>? 7,*apt] ,,ii7 x 0 f\nd t ^! %ields repres5t ! truncat$ angles ( ! r\nd$ tetrah$ral =m t[>d :i* ! planet is t5d+ 7,fig4 #c1 p4 #ab74 ,!ories ( orig9 ( ! m\nta9 arcs4--,! m\nta9 arcs1 :5 /udi$ 9 detail1 are f\nd to be compos$ ( closely fold$ rock /rata1 ! flexures ( :i* are g5]ally s ov]turn$ t _! axial planes dip t[>d ! c5t] ( ! arc 7,fig4 #dgc74 ,x 0 ! view ( ,suess t ^! arcs are to be expla9$ by a pu%+ outw>d ( ! rock /rata f ! c5t] ( ! arc t[>d its p]iph]y1 ?us caus+ a wr9kl+ ( ! surface /rata & an ov]rid+ ( ! surr\nd+ =mations1 :i* ^u ?is hypo!sis oppos$ a great] resi/ance to ! slid+ movem5t4 ,! fold+ toge!r ( ! /rata due to ! slid+ naturally involves a v consid]able dim9ution ( ! surface area pres5t$ by ! /rata 7,fig4 #bb1 p4 #db74 ,9 ! case ( ! ,alp9e *a9s x has be5 e/imat$ t a flat l& area1 f\r hundr$ to eight hundr$ miles across1 has by ! fold+ process be5 r$uc$ to a wid? ( only ab\t "o hundr$ miles1 or f a f\r? to an eigh? ( its =m] wid?4 ,illu/ration3 ,,fig4 #dgc4--;a1 diagram to illu/rate ! ,suess' !ory ( ! orig9 ( m\nta9 arcs2 b1 ! au?or's modification ( ?is view4 ,! weakness ( ,pr(essor ,suess' !ory lies 9 ! fact t su* compression z x implies is assum$ to be due to an outw>d movem5t ( ! relatively small area ( ! e>?'s out] %ell :i* is includ$ )9 ! arc4 ,x mu/ be obvi\s t su* a movem5t1 be+ f a c5t] t[>d ?ree sides at once1 w\ld = ?is circumscrib$ area involve enorm\s proportionate r$uction 9 sup]ficial area ( ! /rata & c\ld only result 9 a hiatus ne> ! c5t] ( ! arc4 ,no su* gap is to be f\nd1 & "o w\ld1 moreov]1 be difficult to acc\nt = ^u any plausible hypo!sis4 ,on ! o!r h&1 ! g5]al contraction ( ! planet z a :ole1 involv+ z x does r$uction ( surface ov] l>ge areas1 is a well-recogniz$ fact2 & if x be true t ! %ields =m$ by ! old] cont95ts are less subject to contraction ?an ! rema9+ portions ( ! surface1 x is easy to und]/& :y ! e>?'s out] sk9 %\ld be wr9kl$ by und]fold+ & ?ru/+ ab\t ^! cont95tal m>g9s4 ,! contra/ ( ?is view ) t ( ,pr(essor ,suess is express$ 9 ! diagrams ( ,fig4 #dgc4 ,illu/ration3 ,,fig4 #dgd4--;,fe/oons ( m\nta9 arcs ab\t ! bord]s ( ! ,pacific ,ocean--,pacific type ( coa/ 7bas$ ^u ,suess74 ,we may illu/rate ?is conception by a /ret*$ %eet ( rubb] clo? su* z is 9 common use by d5ti/s1 ^u :i* a ?9 lay] ( hot ,canada balsam has be5 spread4 ,?is sub/ance congeals ^u cool+ to ne>-normal temp]atures1 & if a small local area ( ! balsam lay] be *ill$ & ! t5sion ^u ! rubb] !n releas$1 ! visc\s balsam ( ! un*ill$ portion ( ! lay] is ?r[n into wr9kles ab\t ! cool$ & m resi/ant areas4 ,^! m resi/ant portions ( ! /ratum may ?us repres5t ! anci5t cont95tal %ields ( our planet4 ,! ,atlantic & ,pacific coa/s contra/$4--,9 8 /udies ( m\nta9 arcs 9 _! relation to ! plan ( ! e>?1 ,pr(essor ,suess has %[n h[ ! arrangem5ts ( ! m\nta9 *a9s ab\t ! two l>g] oceans repres5t two /rongly contra/$ types4 ,:]eas ab\t ! ,pacific m>g9 ! m\nta9 arcs are1 z x 71 /rung 9 fe/oons :i* tr5d p>allel to & are convex t[>d ! coa/1 or else lie 9 fr++ g>l&s ( isl&s 9 ! same attitude 7,fig4 #dgd72 ! m\nta9 *a9s ab\t ! ,atlantic become %>ply truncat$ z !y rea* ! coa/1 & ?us indicate t ! bas9 ( ?is ocean has be5 produc$ by an in?r[ or depression betwe5 great m>g9al displacem5ts 9 "s p]iod subsequ5t to ! =mation ( ! m\nta9s4 ,illu/ration3 ,,fig4 #dge4--,! int]rupt$ sy/em ( ! ,armorican ,m\nta9s common to we/]n ,europe & ea/]n ,nor? ,am]ica 7aft] ,arldt74 ,?us ! m\nta9 folds ( ! ,appala*ian sy/em are 9 ,newf\ndl& cut (f abruptly at ! coa/ l9e1 & ! same b$s1 simil>ly truncat$1 are enc\nt]$ aga9 across ! expanse ( ocean 9 ! folds at ! coa/ ( we/]n ,europe 7,fig4 #dge74 ,9 discont9u\s remnants ?is anci5t m\nta9 *a9 may be trac$ 9 an ea/ & we/ direction across we/]n & c5tral ,europe4 ,we h ?us "h to d ) a s+le m\nta9 sy/em :i* ext5ds f c5tral ,europe to nor!rn ,alabama1 out ( :i* a great l9k has be5 tak5 by ! subsequ5t s9k+ 9 ( ! bas9 ( ! ,atlantic ,ocean4 ,illu/ration3 ,,fig4 #dgf4--,s*ematic repres5tation ( a 8zone ( div]se displacem5t0 9 ! ,great ,bas9 ( ! we/]n ,unit$ ,/ates 7aft] ,p[ell74 ,! block type ( m\nta94--,! inclusion ( mo/ elevations 9 m\nta9 *a9s & arcs is "o ( ! mo/ obvi\s facts to any "o :o has exam9$ _w atlases ) ?is subject 9 m9d4 ,su* *a9s are almo/ inv>iably compos$ ( fold$ rocks1 ?us indicat+ t erosion has remov$ great sup]9cumb5t masses ( /rata s9ce ! cru/al compression produc$ ! folds at consid]able dep?s bel[ ! !n surface4 ,!re are1 h[ev]1 l>ge elevat$ tracts ^u ! e>?'s surface :i* are int]sect$ by deep valleys1 b :]e no arrangem5t ( ! elevat$ portions )9 *a9s or ranges is to be detect$4 ,9 su* cases ! di/ribution ( m\nta9 & valley may be> a resemblance to a mosaic ( di/urb$ p>ts :i* /& at diff]5t levels 7,fig4 #dgf74 ,illu/ration3 ,,fig4 #dgg4--,section ( an ,ea/ ,african block m\nta9 7aft] ,j4 ,w4 ,gregory74 ,su* block m\nta9 di/ricts are to be f\nd 9 _m p>ts ( ! e>?'s surface1 b notably )9 ! ,great ,bas9 ( ! we/]n ,unit$ ,/ates1 & 9 ! l& area :i* bord]s ! ,indian ,ocean ^u ! we/ & nor?we/4 ,9 contra/ ) ! m\nta9 arcs1 s /rik+ly exemplifi$ by ! cont95t ( ,asia z a :ole1 its extreme s\?we/]n portion is made up ( an alt]nation ( plateau & rift valley sep>at$ f ea* o!r by great displacem5ts4 ,?\gh modifi$ to "s ext5t by erosion1 ! elevations seem g5]ally to repres5t ! displac$ cru/ blocks :i* 9 mutual adju/m5ts h be5 left at ! highe/ levels 7,fig4 #dgg74 ,! valley ( ! ,jordan1 ) ! m\nta9s ( ,lebanon ris+ above x1 is ne> ! nor!rn extremity ( ?is fault$ m\nta9 region 7,fig4 #dcd1 p4 #djd71 :ile ! ,great ,rift valley1 cross+ ea/ ,c5tral ,africa1 & ! _m neighbor+ rifts to ! ea/ & we/1 are grav5 9 l9es s deep t an obs]v] ^u a neighbor+ planet might p]haps detect !m4 ,x is n necess>y 9 all cases to assume t ! block m\nta9s ( a fault$ di/rict repres5t ! blocks :i* 9 ! adju/m5ts 7 left ! highe/4 ,erosion 9 ! c\rse ( "t accompli%es m>vels ( trans=mation1 & x may result t heavy masses ( m resi/ant rock ev5tually project ! highe/1 ev5 ?\gh !y may repres5t ! d[n?r[n blocks 9 ! fault mosaic 7,fig4 #dc1 p4 #fj74 ,illu/ration3 ,,fig4 #dgh4--,tilt$ cru/ blocks 9 ! ,queant[eap valley4 ,:]e 9 addition to und]go+ *anges ( level ! e>? blocks h be5 tilt$1 ! features long s9ce describ$ f our we/]n int]ior bas9 z 8,bas9 ,range /ructure0 are develop$4 ,"h ! upp] surface ( ! di/urb$ e>? blocks betrays ! evid5ce ( a def9ite tilt 9 "s "o direction 7,fig4 #dgh1 & ,fig4 #dca1 p4 #djb74 ,m\nta9s ( outfl[ or upheap4--,an important type ( m\nta91 g5]ally describ$ z volcanic1 may be due ei!r to ! outfl[ ( lava at ! e>?'s surface1 or to accumulations ( sep>at$ fragm5ts ( lava1 fir/ ?r[n into ! air1 & !n deposit$ by gravity or admix$ ) wat] z volcanic mud4 ,su* m\nta9s1 bo? be=e & aft] modification by erosion1 assume ! /rik+ly *>act]i/ic =ms :i* h be5 fully discuss$ 9 ,*apt]s ,,ix & ,x4 ,! dom9ant types are ! lava dome & ! puy1 ! c9d] cone1 & ! m complex composite cone4 ,except+ only ! surface produc$ by ! few great fissure eruptions & ! semivolcanic mesa type1 ! individual m\nta9s ( volcanic orig9 develop features ) notably circul> bases4 ,illu/ration3 ,,fig4 #dgi4--,p5 draw+ ( ! laccolite ( ! ,c>riso ,m\nta9 by ,w4 ,h4 ,holmes1 :i* %[s ! jagg$ surface ( ! igne\s rock core & ! slop+ tables :i* /ill rema9 ( ! ro( ( s$im5t>y rocks 7aft] ,cross74 ,illu/ration3 ,,fig4 #dhj4--,map ( laccolitic m\nta9s4 ,a portion ( ! ,judi? ,m\nta9s1 ,montana4 ,! intrusive igne\s rock is %[n 9 black 7aft] ,we$74 ,dom$ m\nta9s ( uplift--laccolites4--,at a consid]able numb] ( widely sep>at$ localities ^u ! e>?'s surface1 m\nta9\s regions are enc\nt]$1 ! c5tral areas or cores ( :i* are compos$ ( intrusive igne\s rock su* z granite1 & ab\t ?is core ! s$im5ts dip away 9 all directions z ?\gh !y _h once =m$ a cont9u\s ro( above x & _h be5 =c$ into ?is dome by hydro/atic pressure ( ! once visc\s mat]ial b5ea? 7,fig4 #aeb1 p4 #adc1 & ,figs4 #dgi & #dhj74 ,examples ( su* dom$ m\nta9s ( uplift 7 fir/ describ$ by ,gilb]t f ! ,h5ry ,m\nta9s ( ,utah1 b in/ances are furni%$ by _m elevat$ tracts1 especially )9 ! we/]n ,unit$ ,/ates4 ,su* m\nta9s are kn[n z laccolites1 b :5 "o m>g9 at lea/ ( ! igne\s core corresponds to a displacem5t1 ! m\nta9 is describ$ z a bysmalite 7,fig4 #dha74 ,illu/ration3 ,,fig4 #dha4--;,ideal sections ( laccolite & bysmalite4 ,:5 subject$ to long-cont9u$ erosion1 ! g5]ally fissur$ granitic core ( ! laccolite wea!rs 9 a :olly diff]5t mann] f ! b$d$ s$im5ts :i* surr\nd & /ill 9 "p m\nt ov] x4 ,! =m] usually pres5ts a m or less jagg$ surface :i* contra/s %>ply ) ! g5tly slop+ tables ( ! latt] 7,fig4 #dgi74 ,ab\t ! high granite core ( ! m\nta91 ! sev]al /rata ( ! uptilt$ =mations pres5t ea* a /eep slope t[>d ?is high] l&1 & a g5tl] slope 9 ! opposite direction4 ,su* unsymmetrical ridges :i* surr\nd ! m\nta9 area are (t5 ref]r$ to z 8hog backs0 7plate #ab ,b74 ,! arrangem5t ( ! /rata 9 ! hog backs ?us pres5ts an ov]lapp+ s]ies l ! %+les ^u a ro(1 except t ! ov]lapp+ is "h f ! bottom in/ead ( ! top1 & ! expos$ ends ?us face t[>d ! cre/4 ,unlike a %+le ro( ! hog backs d n %$ ! wat] :i* desc5ds to !m f ! high] levels1 b1 on ! contr>y1 !y cause x to fl[ 9 tr\ghs p>allel to ! base ( ! slope except :]e outlets are f\nd ?r\gh !m4 ,m\nta9s c>v$ f plateaus4--,9 ! m\nta9 types ?us f> discuss$1 ! local uplift+ ( ! l& has itself develop$ features :i* 9 ! aggregate may be ref]r$ to z m\nta9s1 ev5 ?\gh ! *>act]s ( ! orig9al surface are soon de/roy$ by erosive processes ( "o sort or ! o!r4 ,erosive processes are1 h[ev]1 q compet5t to produce m\nta9 =ms f a featureless plateau1 & p>ticul>ly ?r\gh ! incision by /reams ( runn+ wat]1 ! be/ /udi$ process ( m\nta9 sculpture 7see ,*apt]s ,,xi-,,xiii74 ,?is process ( ?r[+ valleys ab\t an elevat$ section ( ! e>?'s surface1 & s c>v+ out m\nta9s1 is sometimes describ$ z circumvallation2 & if ! t]m 8m\nta90 be appli$ 9 its ord9>y s5se to describe an individual feature1 x is cle> t mo/ m\nta9s h be5 =m$ 9 ?is way4 ,to discuss ! *>act]i/ic %apes ( su* m\nta9s w\ld be l>gely to review ! cont5ts ( ?is book1 & especially ^? portions :i* discuss ! "* pr(iles result+ f ! action ( ea* sculptur+ or mold+ ag5t4 ,! "w ( fro/ & o!r wea!r+ ag5cies1 ( runn+ wat]1 ( m\nta9 & ( cont95tal glaci]1 w\ld all h to be consid]$ 9 ord] to evolve ! hi/ory ( ea* m\nta94 ,9 addition to discov]+ ! ag5ts :i* 7 *iefly responsible = ! %ap+ ( ! m\nta91 we may1 fur!r1 9 _m cases det]m9e at :at /age ! "w ( "o ag5t has be5 succe$$ by t ( ano!r1 & at lea/ at :at /age ( its complete cycle ( activity ! late/ ag5t is n[ at "w4 ,illu/ration3 ,,fig4 #dhb4--,! gabl$ faade s l>gely develop$ 9 des]t l&scapes & %>ply contra/$ ) ! recurr+ curves 9 ! l&scapes ( humid di/ricts 7f a pa9t+ ( ! ,gr& ,caon ( ! ,colorado by ,moran74 ,! climatic conditions ( ! m\nta9 sculpture4--,s9ce ! diff]5t geological ag5cies op]ate ei!r 9 a diff]5t mann] or ) diff]5ces 9 vigor accord+ to ! v>y+ climatic conditions1 ! m\nta9s ( arid regions may 9 mo/ cases be readily diff]5tiat$ f ^? ( ! m habitable humid sections ( c\ntry4 ,9 broad l9es ^! diff]5ces may be summ$ up 9 ! great] preval5ce ( ! curv+ l9e )9 ! l&scapes ( humid di/ricts4 ,?is may be l>gely ascrib$ to ! influ5ce ( ! mat ( vegetation1 :i* protects ! rock surface f m rapid me*anical deg5]ation1 & arre/s ! slid+ movem5ts )9 ! already loos5$ rock dbris4 ,9 place ( ! rev]s$ curves ( ! l9es ( beauty1 s g5]ally obs]v$ 9 ! l&scapes ( well-wat]$ regions1 ! des]t l&s pres5t ev] a repetition ( ! v]tical cliff alt]nat+ ) a sort ( _m gabl$ faade :i* is occasionally due to truncation ( m\nta9 spurs by ! waves ( =m] lakes1 b f> m (t5 ! outl9es ( dbris cones built up b5ea? ea* prom95t jo9t ( ! cliff walls 7,fig4 #dhb74 ,! effect ( ! resi/ant /ratum4--,9 a /rik+ mann] m\nta9 l&scapes may disclose ! influ5ce ( ! div]sifi$ rock mat]ials & ( ! rock /ructures z well4 ,aft] prolong$ erosion !re is likely to be little correspond5ce betwe5 ! positions ( ! anticl9al folds & ! cre/s ( ! high] m\nta9s4 ,su* m\nta9s are1 9 fact1 mu* m likely to rise ov] syncl9es ?an ^u ! site ( anticl9es4 ,! travel] :o ent]s ! ,alps by any ( ! sev]al railways1 or :o j\rneys by /eam] ov] ! beautiful lake ( ,luc]ne1 has a mo/ favorable opportunity to /udy ! position ( ! rock folds 9 ! m\nta9 sections t are unroll$ 9 succession be=e him4 ,r>ely inde$ w he f9d a def9ite anticl9e 9 correspond5ce ) a m\nta9 peak1 = ! lay]s :i* are mo/ resi/ant h develop$ ! peaks1 & x is because ! out] lay]s ( ! anticl9es op5 by local t5sion 7see ,fig4 #bf1 p4 #de7 t !y 7 fir/ cut away by erosion1 s t ! h>d lay]s )9 ! syncl9es are likely to con/itute ! peaks )9 ! exi/+ surface4 ,illu/ration3 ,,fig4 #dhc4--,! ,my!n1 compos$ ( ,jurassic & ,cretace\s s$im5ts1 & re/+ ^u s(t] ,t]ti>y =mations4 ,view f a balloon 7aft] a photograph by ,c4 ,s*midt74 ,:51 z sometimes happ5s1 an old] & likewise m resi/ant b$ has be5 fold$ back ^u y\ng] & s(t] =mations1 an isolat$ remnant may be f\nd 8unroot$0 to its base1 ^u :i* x appe>s z ?\gh float+ )9 a bill[y sea ( ! s(t] =mations 7,fig4 #dhc74 ,! m>k ( ! rift 9 ! erod$ m\nta9s4--,apply+ ! t]m 8m\nta90 9 its collective s5se = a circumscrib$ area ( uplift$ cru/1 :e!r repres5t$ to-day by a fold$ or a fault$ complex1 a lava mass1 or a granite dome2 ! p]iod ( uplift has m>k$ ! beg9n+ ( ! activity ( sculptur+ ag5cies4 ,by ^! ! mass is p>$ d[n z x is %ap$ into a m or less intricate design ( compon5t & ess5tially repeat+ units4 ,9 ! v]nacul> ! ^w 8m\nta90 is appli$ to ^! units into :i* ! l>g] m\nta9 mass is subdivid$4 ,illu/ration3 ,,fig4 #dhd4--,! battlem5t type ( erosion m\nta9s4 ,die ,drei ,z9n5 7,?ree ,battlem5ts7 9 ! ,dolomites 7aft] ,m>r74 ,x has be5 "o ( ! ma9 objects ( ?is "w to po9t out t ! peculi> %apes ( ^! elem5t>y m\nta9s are ea* *>act]i/ic ( ! erosive ag5ts :i* produc$ !m1 & t ea* surface has m>ks :i* may be recogniz$ 9 ^? l9es ( pr(ile :i* recur )9 ! l&scape--! "* pr(iles4 ,9 ! subdivision ( ! l>g] mass--! g5etical m\nta9--to =m ! num]\s small] masses--! erosional or circumvallational m\nta9s--!re is disclos$ a patt]n ( fractures :i* has guid$ ! erosional ag5ts 9 _! incisional op]ations 7see ,*apt] ,,xvii74 ,9 high altitudes1 :]e ! action ( fro/ is s pot5t 9 pry+ at ! wid] fractures1 ?is subdivision ( ! mass may be reveal$ by ! sculptur+ ( squ>$ t[]s or battlem5ts 7,fig4 #dhd74 ,illu/ration3 ,,fig4 #dhe4--,symmetrically =m$ l[ isl&s repeat$ 9 ranks ^u ,temagami ,lake1 ,ont>io4 ,= o!r examples 9 :i* ! sculptur$ surface is l>gely ! h&iwork ( a s+le erosional ag5t1 z ov] va/ areas 9 ! ,canadian wild]ness1 ! revelation ( ! fracture design is no less app>5t4 ,"h a s]ies ( cry/all9e rocks und]lie broad expanses ( t]ritory & are )\t notewor?y v>iations ( h>dness & almo/ b>e ( surface dbris4 ,sculptur$ b5ea? a mantl+ ice %eet1 excavation has naturally be5 conc5trat$ above ! m widely gap+ fissures ( ! jo9t-fault sy/em1 d\btless already m>k$ out 9 ! riv] network :i* ! glaci] ov]rode4 ,! result has be5 a division ( ! surface into a s]ies ( l[1 oval ridges or hummocks1 :i* ov] va/ areas are repeat$ ) monoton\s regul>ity4 ,:]ev] ! l[] levels h be5 flood$1 symmetrical l[ isl&s ( ne>ly uni=m elevation rise f ! expanse ( wat] & may be c\nt$ by ?\s&s4 ,?\gh ! small] isl&s h notably regul> %ore l9es1 ! l>g] ones disclose _! composition f small] units by ! break+ ( _! %ores into simil> bays spac$ ) regul> int]vals 7,fig4 #dhe1 & ,figs4 #bdc & #bde1 p4 #bbi74 ,! ev] repeat+ fracture design ( ! e>?'s cru/ is n re/rict$ to ! m\nta9 masses :i* x has brok5 up1 & ! unity ( :i* x has done s mu* to conceal4 ,x ext5ds f> outside ! m>g9 ( ^! masses1 & is 9 fact common to :ole cont95ts & p]haps ev5 to ! planet z a :ole4 ,! "p play$ by ?is design ( fractures 9 ! control ( ! sculpture ( l&scapes x w\ld be h>d to ov]e/imate4 ,?r\gh its influ5ce ! /rik+ features mold$ by "o ag5t h be5 m]g$ 9 ! contra/$ %apes develop$ by ano!r4 ,x is ! great outl9e bl5d] 9 ! creation ( nature's ma/]pieces ( =m & color4 ,?us ! l9es ( ?is my/]i\s fracture network1 ?\gh /amp$ 9 indelible *>act]s ^u our l&scapes1 are g5]ally lo/ 9 ! ensemble effect & may long rema9 undiscov]$4 ,l a moss-gr[n inscription ^u a slab ( m>ble1 ?\gh veil$1 x may yet be deciph]$2 & if ! veil be )drawn1 ! runic *>act]s are disclos$1 & "o ( nature's laws lies op5 be=e u4 ,,read+ ,,ref]5ces ,,= ,,*apt] ,,xxxi ,m\nta9 arcs or fe/oons3-- ,,ed4 ,,suess4 ,! ,face ( ! ,e>?1 vol4 #b1 #aijf1 pp4 #bja-bjg2 vol4 #d1 #aiji1 pp4 #dih-edb4 ,block m\nta9s3-- ,g4 ,k4 ,,gilb]t4 ,surveys ,we/ ( ! #ajj? ,m]idian 7,:eel]71 vol4 #c1 ,geology1 ,wa%+ton1 #ahge1 ,pt4 #a1 pp4 #ai et seq41 #dh4 ,j4 ,w4 ,,p[ell4 ,report on ! ,geology ( ! ,ea/]n ,portion ( ! ,u9ta ,m\nta9s & a ,region ( ,c\ntry ,adjac5t !reto1 ,u4 ,s4 ,geol4 & ,geogr4 ,surv4 ,t]41 ,,ii ,div4 ,wa%+ton1 #ahgf1 pp4 #bah4 ,,john ,w4 ,,gregory4 ,! ,great ,rift ,valley4 ,london1 #ahif1 pp4 #dbb4 ,laccolites & bysmalites3-- ,g4 ,k4 ,,gilb]t4 ,report on ! ,geology ( ! ,h5ry ,m\nta9s1 ,u4 ,s4 ,geol4 & ,geogr4 ,surv4 ,t]41 #ahgg1 pp4 #ah-ih4 ,,:itman ,,cross4 ,! ,laccolitic ,m\nta9 ,gr\ps ( ,colorado1 ,utah1 & ,arizona1 #ad? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 #ahie1 pp4 #aeg-bda1 pls4 #g-af4 ,w4 ,h4 ,,we$ & ,l4 ,v4 ,,pirsson4 ,geology & ,m9]al ,res\rces ( ! ,judi? ,m\nta9s ( ,montana1 #ah? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 iii1 #ahih1 pp4 #dhe-eef1 pl4 #ge4 ,w4 ,h4 ,,we$4 ,geology ( ! ,little ,belt ,m\nta9s1 ,montana1 etc41 #bj? ,ann4 ,rept4 ,u4 ,s4 ,geol4 ,surv41 ,pt4 iii1 #aijj1 pp4 #chg-djj4 ,,v]a ,,de ,,d]wies4 ,re*]*es gologiques et ptrographiques sur les loccoli!s des environs de ,piatigorsk 7,caucase du ,nord74 ,g5eva1 #aije1 pp4 #hd1 pls4 #c4 ,r4 ,a4 ,,daly4 ,! ,me*anics ( ,igne\s ,intrusion1 ,am4 ,j\r4 ,sci4 7#d71 vol4 #ae1 #aijc1 pp4 #bfi-bgh2 vol4 #af1 #aijc1 pp4 #ajg-abf4 ,,joseph ,,b>rell4 ,geology ( ! ,m>ysville ,m9+ ,di/rict1 ,montana4 ,a /udy ( ,igne\s ,intrusion & ,contact ,metamorphism4 ,pr(4 ,pap4 #eg1 ,u4 ,s4 ,geol4 ,surv41 #aijg1 pp4 #aea-agh4 ,climatic condition 9 relation to l& sculpture3-- ,c4 ,e4 ,,dutton4 ,t]ti>y ,hi/ory ( ! ,gr& ,canyon ,di/rict1 ,mon4 #b1 ,u4 ,s4 ,geol4 ,surv41 #ahhb1 pp4 #bfd1 pls4 #db4 ,,app5dix ,a ,,! ,,quick ,,det]m9ation ,,( ,,! ,,common ,,m9]als ,be=e "o may ga9 a k ( rocks or ! ar*itecture ( _! arrangem5t )9 ! e>?'s cru/1 x is q ess5tial t "s famili>ity %\ld be acquir$ ) ! appe>ance & prop]ties ( ! commone/ m9]als1 & p>ticul>ly ^? :i* ent] z ess5tial con/itu5ts into ! m abundant rocks4 ,to be a compet5t m9]alogi/1 "o mu/ h a r ext5d$ k bo? ( inorganic *emi/ry & ( ! sci5ce ( cry/allography1 :i*1 fasc9at+ z x is to /udy1 involves "s te*nical k ( ma!matics & mu* laboratory exp]i5ce4 ,?\gh necess>y to any "o :o contemplates mak+ a c>e] z a geologi/1 ?is special /udy is n ess5tial to a cultural c\rse l ! pres5t "o4 ,! attempt w "h be made to br+ toge!r a body ( fact1 f ! /udy ( :i* ! /ud5t may quickly le>n to recognize ! commone/ m9]als 9 _! usual v>ieties4 ,! te/s he is to apply are ma9ly physical1 & 9 place ( an elaborate discussion ( cry/al symmetry1 pictures only c be suppli$4 ,to ! beg9n] ! usual textbook ( m9]alogy is difficult to read intellig5tly1 = ! reason t = ea* m9]al species x sets be=e him a catalogue ( ea* physical prop]ty 9 its turn1 ) little indication ( ^? data :i* 9 ! individual case h special diagno/ic value4 ,none ! less1 h[ev]1 ! /ud5t is advis$ to consid] ! sev]al prop]ties ( ea* m9]al 9 a def9ite ord]1 & ! foll[+ may s]ve z well z any3 cry/al or o!r =m1 cleavage1 fracture1 lu/]1 color1 /reak1 transp>5cy1 t5acity1 h>dness1 magnetism1 & specific gravity4 ,9 endeavor+ to connect ! specific values ( ^! prop]ties ) individual m9]al species1 ! *emical composition & ! mann] ( occurr5ce are n to be =gott54 ,x is well = ! /ud5t to be suppli$ ) a small pocket l5s & ) a pocket knife ! blade ( :i* has be5 magnetiz$4 ,cry/al =m4--,"s m9]al species g5]ally occur 9 m or less def9ite cry/als--are b\nd$ by def9ite plane surfaces develop$ :5 ! m9]al 0 =m$2 o!rs 9 gr\ps ( int]f]+ cry/als or aggregates1 9 :i* case ! m9]al is said to be cry/all9e2 :ile /ill o!rs are r>ely f\nd cry/alliz$ at all4 ,?us 9 a giv5 case cry/al =m may1 or may n1 be important = ! diagnosis ( ! sub/ance4 ,if a m9]al species is usually to be f\nd 9 cry/als1 ! /ud5t %\ld be aw>e ( ! fact1 & if possible %\ld h a m5tal picture ( ! common cry/al %ape or %apes4 ,)\t an ext5d$ k ( cry/allography1 ?is mu/ be suppli$ him by draw+s4 ,s9ce cry/als ( mo/ species are apt to be di/ort$1 ow+ to ! fact t "s planes )9 ! same gr\p appe> ^u ! cry/al ) a l>g] developm5t ?an o!rs1 x is conv5i5t to rememb] t m>k+s1 su* z l9es or et*+s ^u ! cry/al faces1 are ! same ?r\gh\t ! same gr\p ( planes1 & 9 ! text figures su* gr\ps ( planes are indicat$ by ! use ( a common lett]4 ,= cry/all9e aggregates su* t]ms z fibr\s1 radiat+1 massive1 or granul> h _! usual mean+s4 ,cleavage4--,x is *>act]i/ic ( mo/ cry/als t !y break or cleave along c]ta9 directions s z to leave plane or ne>ly plane surfaces1 & ! lu/] ( ! cleav$ surface measures ! p]fection ( ! cleavage prop]ty4 ,x is important always to note h[ _m su* directions ( cleavage are pres5t1 &1 r\ghly at lea/1 at :at angles !y int]sect--:e!r !y are p]p5dicul> to ea* o!r or incl9$ at "s o!r angle4 ,fur!r1 x %\ld be not$ :e!r a giv5 cleavage is p]fect1 t is1 easy1 :i* w be indicat$ by ! ?9ness ( ! plates :i* c be secur$4 ,an extremely p]fect cleavage is possess$ by ! m9]al mica1 ^: plates are ?9n] ?an ! ?9ne/ pap]4 ,9 ! case ( imp]fect or int]rupt$ cleavage1 ! fracture surfaces are n plane ?r\gh\t1 b int]rupt$1 ! surface 8jump+0 f "o plane to a neighbor+ p>allel "o4 ,x is especially important to note :e!r1 9 ! case ( sev]al cleavages possess$ by a cry/al1 all h ! same degree ( p]fection1 or :e!r !y exhibit diff]5ces4 ,fracture4--,9 m9]als ) poorly develop$ cleavage1 ! fracture surface is describ$ z fracture4 ,fracture is ?us p]fect 9 proportion z cleavage is imp]fect4 ,! fracture is describ$ z con*oidal :5 x %[s wav+ sph]ical surfaces l brok5 glass4 ,= f9e aggregates ! fracture is describ$ z ev51 unev51 e>?y1 etc41 names :i* are g5]ally intelligible4 ,lu/]4--,?is t]m is appli$ especially to ! mann] 9 :i* light is reflect$ f m9]al surfaces4 ,! mo/ important di/9ction is made betwe5 ^? m9]als :i* h a metallic lu/] & ^? :i* h n1 ! =m] be+ always opaque4 ,o!r *>act]i/ic lu/]s are adamant9e 7l oil$ glass71 vitre\s 7glassy71 res9\s1 waxy1 etc4 ,color4--,= m9]als :i* possess metallic lu/] ! color is always practically ! same1 & h5ce x becomes a valuable diagno/ic prop]ty4 ,( m9]als :i* h nonmetallic lu/]1 ! color may be always ! same & h5ce *>act]i/ic1 b 9 ! case ( _m m9]als x ranges betwe5 wide limits & sometimes runs almo/ ! entire gamut ( hues1 yet )\t appreciable *anges 9 ! *emical composition ( ! m9]al4 ,/reak4--,?is t]m is appli$ to ! color ( ! m9]al p[d]1 & is usually fairly con/ant1 ev5 :5 ! surface color ( diff]5t specim5s may v>y )9 wide limits4 ,9 ! case ( fairly s(t m9]als ! /reak is be/ exam9$ by mak+ a m>k on a piece ( unglaz$ porcela9 7/reak /one74 ,transp>5cy 7diaphaneity74--,! t]ms 8transp>5t01 8transluc5t01 8subtransluc5t01 & 8opaque0 are us$ to describe decreas+ grades ( p]meability by light rays4 ,?r\gh transp>5t bodies pr9t may be read1 :ile transluc5t bodies all[ ! light to be transmitt$ 9 consid]able quantity ?r\gh !m1 ?\gh )\t r5d]+ ! image ( objects4 ,t5acity4--,?is compreh5sive t]m includes su* prop]ties z brittl5ess1 flexibility1 ela/icity1 malleability1 etc4 ,h>dness4--,q errone\s notions are held conc]n+ ! mean+ ( ?is v common ^w1 :i* prop]ly implies a resi/ance (f]$ to abrasion4 ,x is "o ( ! mo/ valuable prop]ties = ! quick det]m9ation ( m9]als1 s9ce m9]als range f diamond ^u ! "o h&--! h>de/ ( sub/ances--to talc & graphite1 :i* are s s(t z to be deeply scrat*$ by ! ?umb nail4 ,= practical purposes x is suffici5t to make use ( a r\gh scale ( h>dness made up f common or well-kn[n m9]als4 ,if we exclude ! gem m9]als1 ?is scale ne$ include b sev5 numb]s1 :i* are3 talc1 #a2 gypsum1 #b2 calcite1 #c2 fluor sp>1 #d2 apatite1 #e2 feldsp>1 #f2 & qu>tz1 #g4 ,a giv5 m9]al is s(t] ?an a m9]al 9 ! scale :5 x c be visibly scrat*$ by a scale m9]al1 b w n leave a scrat* :5 ! conditions are rev]s$4 ,if ea* w scrat* ! o!r ) equal read9ess1 ! two m9]als h ! same h>dness4 ,s9ce x may (t5 be desirable to te/ m9]al h>dness :5 no scale is at h&1 ! foll[+ sub/itutes may be made use (3 #a1 greasy feel & easily scrat*$ by ! ?umb nail2 #b1 takes a scrat* f ! ?umb nail1 b mu* less readily2 #c1 scrat*$ by a copp] co9 & v easily by a pocket knife2 #d1 scrat*$ )\t difficulty by a knife2 #e1 scrat*$ ) difficulty by a knife1 b easily by w9d[ glass2 #f1 scrat*$ by w9d[ glass2 #g1 scrat*es w9d[ glass ) read9ess1 b a gra9 ( s& may be sub/itut$ to repres5t qu>tz 9 ! scale4 ,magnetism4--,?\gh ne>ly all m9]als :i* conta9 important quantities ( ! elem5ts iron1 cobalt1 or nickel may be attract$ to a /rong electromagnet1 !re are b two common m9]als1 & ^! ( widely diff]5t appe>ance1 ^: p[d] is lift$ by a common magnet4 ,o!rs are1 h[ev]1 lift$ aft] /rong heat+ 9 ! air 7ignition71 & ?is is a valuable te/4 ,specific gravity4--,r\gh te/s ( relative weight1 or specific gravity1 may be made by lift+ fair-siz$ specim5s 9 ! h&4 ,bett] det]m9ations require ! use ( a spr+ balance4 ,treatm5t ) acid4--,! c>bonate m9]als react ) w>m & dilute m9]al acid s z to give a boil+ effect 7eff]vesc5ce71 s9ce c>bonic acid gas escapes into ! air 9 ! process4 ,,prop]ties ,,( ,,! ,,common ,,m9]als ,! m important common m9]als fall into two classes accord+ z !y h l>ge economic importance z ores1 or ent] 9 an important way into ! composition ( rocks4 ,i4 ,! ,m9]als ( ,economic ,importance ,hematite4--,! sesquioxide ( iron1 ,fe#b,o#c1 & by f> ! mo/ important ore ( iron4 ,r>ely 9 good cry/als1 b sometimes 9 ?9 opaque scales be>+ "s resemblance to mica & kn[n z micace\s or specul> iron ore4 ,at o!r times 9 nodules built up f radial ne$les 7ne$le ore72 9 h>d masses mix$ ) f9e qu>tz gra9s 7h>d hematite72 or 9 s(t r$di% br[n e>? 7s(t hematite74 ,color1 black to *]ry r$4 ,! p[d]$ m9]al always *]ry r$ or r$di% br[n1 & easily lift$ by ! magnet aft] ignition4 ,h>dness #e4e-f4e2 specific gravity #e4 ,magnetite4--,! magnetic oxide ( iron1 ,fe#c,o#d1 (t5 9 cry/als l ,fig4 #dhf1 #a-b4 ,black & opaque ) a metallic lu/]4 ,/reak black4 ,lift$ by a magnet & sometimes itself capable ( lift+ fil+s ( s(t iron 7lode/one74 ,h>dness #e4e-f4e4 ,specific gravity #e4 ,limonite4--,! mo/ abundant & mo/ valuable ( ! hydrat$ iron ores1 #b ,fe#b,o#c4 #c ,h#b,o4 ,*emical composition ! same z iron ru/1 ) :i* 9 ! e>?y =m x is id5tical4 ,nev] 9 cry/als1 b (t5 9 mammill>y or r\nd$ p5dant =ms resembl+ icicles1 or sometimes clu/]s ( grapes4 ,its yell[ 7ru/7 /reak is its be/ diagno/ic prop]ty4 ,ignit$ x gives (f wat] & becomes magnetic4 ,! /reak & its notably l[] specific gravity di/+ui% x f c]ta9 =ms ( hematite :i* x outw>dly resembles4 ,h>dness #e-e4e4 ,specific gravity #c4f-d4 ,pyrite1 iron pyrites1 or 8fool's gold40--,! sulphide ( iron1 ,fe,s#b4 ,! mo/ widely di/ribut$ sulphide m9]al & n[ a *ief s\rce ( ! great *emical reag5t1 sulphuric acid or vitriol4 ,(t51 b n always1 9 cry/als 7,fig4 #dhf1 #c-e7 :i* h peculi> /ri ^u _! faces4 ,at o!r times ! m9]al is f\nd massive or 9 radiat$ ne$les4 ,bright metallic lu/] ) ! color ( new brass1 ?\gh (t5 t>ni%$ or alt]$ ^u ! surface to limonite4 ,h>d & brittle1 & s di/+ui%$ f gold1 :i* is s(t & malleable & ( ! color ( ! pal] old brass 7:i* conta9$ a l>g] p]c5tage ( z9c74 ,gold is1 fur!r1 ab\t f\r times z heavy z pyrite4 ,h>dness #f-f4e4 ,specific gravity #e4 ,*alcopyrite1 copp] pyrites4--,a mix$ sulphide ( copp] & iron4 ,if 9 cry/als1 l ,fig4 #dhf1 #f2 o!rwise massive or compact4 ,lu/] metallic4 ,color orange-yell[1 (t5 ) local blue & gre5 iridesc5ce l a pigeon's ?roat4 ,di/+ui%$ f pyrite by ! deep] color & l[] h>dness1 & f gold1 p>ticul>ly1 by its brittl5ess & l[] specific gravity4 ,h>dness #c4e-d4 ,specific gravity #d4 ,gal5ite1 gal5a4--,sulphide ( lead1 ,pb,s4 ,! *ief ore ( lead1 &1 f admixture ( a silv] m9]al1 ( silv] z well4 ,usually f\nd 9 cry/als 7,fig4 #dhf1 #g74 ,always cleaves into blocks b\nd$ by six v p]fect rectangul> faces :i*1 :5 fre%ly brok51 %[ a bright silv]y lu/] & quickly t>ni% to a peculi>ly 8lead50 surface4 ,v heavy4 ,color & /reak lead-gray4 ,h>dness #b4e4 ,specific gravity #g4e4 ,sphal]ite1 z9c bl5de4--,sulphide ( z9c1 ,zn,s1 usually ) consid]able admixture ( sulphide ( iron4 ,! great ore ( z9c4 ,n infrequ5tly 9 cry/als 7,fig4 #dhf1 #h-i71 b m (t5 9 cleavable cry/all9e aggregates4 ,! cleavage 9 f9e aggregates is sometimes difficult to make out1 b 9 co>se-gra9$ masses x is se5 to be equally & highly p]fect 9 six diff]5t directions1 s t a symmetrical twelve-fac$ =m may sometimes be brok5 out 7dodecah$ron74 ,lu/] l t ( ros9 7ros9 jack71 ?\gh :5 ) l>ge iron admixture ! color may approa* black 7black jack74 ,! light] color$ v>ieties are transluc5t4 ,h>dness #c4e-d4 ,specific gravity #d4 ,mala*ite4--,hydrat$ 7basic7 copp] c>bonate4 ,! gre5 copp] ore & ! common surface alt]ation product ( o!r copp] m9]als4 ,usually has a microscopic /ructure made up ( f9e ne$le-l cry/als1 b g5]ally massive 9 v>i\s imitative %apes n unlike ^? ( ! iron ores4 ,sometimes e>?y4 ,its color is bright gre51 & x is usually f\nd 9 association ) o!r *>act]i/ic copp] ores1 su* z *alcopyrite & azurite4 ,:5 relatively pure & 9 l>ge masses1 x is a beautiful ornam5tal /one4 ,eff]vesces ) acid4 ,h>dness #c4e-d4 ,specific gravity #d4 ,illu/ration3 ,,fig4 #dhf4--;,=ms ( ,cry/als3 #a-b1 magnetite2 #c-e1 pyrite2 #f1 *alcopyrite2 #g1 gal5ite2 #h-i1 sphal]ite2 #aj-ac1 calcite4 ,azurite4--,hydrat$ 7basic7 copp] c>bonate1 less hydrat$ ?an mala*ite1 & kn[n z ! blue c>bonate ( copp]4 ,g5]ally 9 v m9ute & q complex cry/als1 b also 9 imitative %apes simil> to ^? ( mala*ite1 & at o!r times e>?y4 ,slightly light] 9 weight ?an mala*ite1 f :i* x is easily di/+ui%$1 z f mo/ o!r m9]als1 by its bright azure blue color & its some:at light] blue /reak4 ,eff]vesces ) nitric acid4 ,h>dness #c4e-d4 ,specific gravity #c4g-c4h4 ,calcite4--,calcium c>bonate1 ,ca,c,o#c4 ,almo/ always 9 cry/als 7,fig4 #dhf1 #aj-ac71 or 9 confus$ cry/al aggregates1 ?\gh r>ely fibr\s or dull & e>?y4 ,"s ( ! =ms ( ! cry/als are describ$ z 8dog-too? sp>01 o!rs z 8nail-head sp>01 :ile /ill o!rs are modifi$ hexagonal prisms4 ,!re is a beautifully p]fect cleavage ( ! m9]al along ?ree directions :i* make angles ( ab\t #aje ) ea* o!r1 s t "u ! hamm] ! sub/ance breaks into blocks :i* are %ap$ l ! cry/al ( ,fig4 #dhf1 #aj4 ,usually :ite or gray1 b occasionally fa9tly t9t$4 ,/reak :ite4 ,eff]vesces ) cold & dilute m9]al acids4 ,an associate ( _m ores & ! *ief m9]al ( lime/one4 ,a simil> m9]al--dolomite--conta9s 9 addition magnesium c>bonate1 has simpl] cry/als 7l ! draw+ ( ,fig4 #dhf1 #aj1 b (t5 ) r\nd$ faces71 & eff]vesces only :5 ! acid is w>m$4 ,h>dness #c4 ,specific gravity #b4g4 ,gypsum4--,hydrat$ calcium sulphate1 ,ca,s,o#d4b ,h#b,o1 & ! s\rce ( pla/] ( ,p>is4 ,(t5 9 simple cry/als 7,fig4 #dhg1 #a7 or else 8swall[ tail01 l ,fig4 #dhg1 #b2 9 :i* case ! m9]al is g5]ally ei!r transp>5t or transluc5t & is describ$ z sel5ite4 ,su* cry/als %[ a cleavage approa*+ 9 p]fection t ( ! micas1 b1 unlike ! mica lam91 ^? produc$ by cleavage 9 gypsum ?\gh flexible are n ela/ic4 ,!re are also fibr\s =ms ( gypsum 7sat9 sp>71 a f9e-gra9$ =m 7alaba/]71 & ! impure e>?y =m 7rock gypsum74 ,v s(t1 light 9 weight1 & difficultly fusible4 ,color usually :ite1 gray1 or pale yell[4 ,h>dness #b4 ,specific gravity #b4c4 ,copp] glance4--,a sulphide ( copp]1 ,cu#b,s4 ,n usually well cry/alliz$1 b g5]ally massive & associat$ or v>i\sly admix$ ) o!r copp] ores su* z *alcopyrite1 mala*ite1 etc4 ,fracture con*oidal1 lu/] metallic1 color & /reak blacki% lead-gray1 ?\gh (t5 t>ni%$ blue or gre5 f surface alt]ations to ! copp] c>bonates4 ,s(t] & heavi] ?an *alcopyrite4 ,bl[pipe or *emical te/s are necess>y = its id5tification4 ,h>dness #b4e-c4 ,specific gravity #e4e-e4h4 ,c]ussite4--,! :ite or c>bonate lead ore1 ,pb,c,o#c1 & an important ore ( silv] z well4 ,(t5 9 cry/als ( consid]able complexity1 ?\gh ,fig4 #dhg1 #c-d1 %[s "s common %apes4 ,(t5 granul>1 massive1 or e>?y 7gray c>bonate ore74 ,v brittle & ) con*oidal fracture4 ,! lu/] is adamant9e or l t ( oil$ glass4 ,color g5]ally :ite or gray4 ,v heavy1 ! heavie/ ( light color$ & nonmetallic m9]als4 ,dissolves 9 nitric acid ) eff]vesc5ce4 ,h>dness #c-c4e4 ,specific gravity #f4e4 ,sid]ite4--,! c>bonate or 8spa?ic0 ore ( iron1 ,fe,c,o#c4 ,ei!r 9 cry/als resembl+ 9 =m ,fig4 #dhf1 #aj1 b ) r\nd$ faces1 or cleavable massive to f9ely granul> & e>?y4 ,! cry/all9e v>ieties cleave easily into small] blocks ( ! same =m z ^? ( calcite4 ,color usually gray or br[n & /reak :ite4 ,on /rongly ignit+1 ! :ite p[d] becomes black & magnetic4 ,light] 9 bo? color & weight ?an ! o!r iron ores1 & unlike !m sid]ite eff]vesces ) acid4 ,di/+ui%$ f calcite by its high] specific gravity & its *ange ^u be+ ignit$4 ,h>dness #c4e-d4 ,specific gravity #c4i4 ,smi?sonite4--,c>bonate ( z9c1 ,zn,c,o#c1 & an important ore ( t metal4 ,seldom f\nd 9 cry/als except z a replacem5t ( calcite cry/als1 9 :i* case x %[s ! =ms *>act]i/ic ( ! latt] m9]al4 ,usually kidney-%ap$1 /alactitic1 or else 9 incru/ations ^u o!r m9]als4 ,sometimes granul> or e>?y4 ,brittle4 ,lu/] vitre\s1 color :ite or gre5i% gray1 ?\gh (t5 /a9$ yell[ ) iron ru/4 ,/reak :ite except :5 ! m9]al is /a9$ ) iron4 ,eff]vesces ) w>m acid4 ,h>dness #e4 ,specific gravity #d4d4 ,pyrolusite4--,black oxide ( manganese1 ,mn,o#b1 ?\gh g5]ally impure f admixture ) o!r manganese oxides4 ,usually 9 intricate aggregates :i* may be column>1 fibr\s1 mammill>y1 e>?y1 etc4 ,opaque1 ) color & /reak bo? black4 ,s(t & easily soils ! f+]s4 ,) hydro*loric acid gives (f ! *ok+ fumes ( *lor9e4 ,h>dness #b-b4e4 ,specific gravity #d4h4 ,,ii4 ,! ,m9]als important z ,rock ,mak]s ,^! m9]als are 9 mo/ cases complex silicates ( "o or m ( a c]ta9 numb] ( metals su* z alum9ium1 calcium1 magnesium1 iron1 sodium1 potassium1 or hydroxyl 7,,oh74 ,= _! id5tification an exam9ation ( ! physical prop]ties is usually suffici5t1 :]eas ( ! typical ore m9]als already consid]$1 additional *emical te/s may be necess>y4 ,feldsp>s4--,a gr\p ( simil> alum9o-silicates ( potassium1 sodium1 & calcium4 ,! mo/ important ( all rock-mak+ m9]als4 ,al?\gh ) wide v>iation 9 *emical composition1 ! feldsp>s are yet broadly divid$ into two classes2 ! "o /riat$1 & ! o!r an un/riat$ pota% or or?oclase v>iety4 ,! pocket l5s is usually necess>y 9 ord] to make out ! /riations ^u ! cry/al or cleavage surfaces4 ,:5 =m$ 9 ve9s1 feldsp> appe>s 9 cry/als 7,fig4 #dhg1 #e-f71 b z a rock con/itu5t ! mutual int]f]5ce ( cry/als prev5ts ! developm5t ( b\nd+ faces4 ,two cleavage directions1 ne>ly or q p]p5dicul> to ea* o!r1 are notably diff]5t 9 _! p]fection4 ,h>d en\gh to scrat* glass1 b easily scrat*$ by s&4 ,color p9k 7usually or?oclase or microl9e71 :ite 7(t5 albite7 to gray4 ,sometimes ) beautiful 8pigeon's ?roat0 effect ( iridesc5ce 7labradorite74 ,l[ specific gravity4 ,h>dness #f4 ,specific gravity #b4e-b4h4 ,illu/ration3 ,,fig4 #dhg4--;,=ms ( ,cry/als3 #a-b1 gypsum2 #c-d1 c]ussite2 #e-f1 feldsp>2 #g1 qu>tz2 #h1 pyrox5e 7cross section72 #i1 hornbl5de 7cross section72 #aj1 g>net2 #aa1 nephelite2 #ab-ad1 /aurolite2 #ae-af1 t\rmal9e 7cross sections72 #ag1 oliv9e4 ,qu>tz4--,oxide ( silicon or silica1 ,si,o#b4 ,bo? an important ve9 m9]al associat$ ) ! ores & a rock mak]4 ,9 ! =m] case p>ticul>ly1 (t5 9 cry/als ( notably simple =ms 7,fig4 #dhg1 #g74 ,few m9]als :i* are n gems are s h>d4 ,rem>kable fre$om f cleavage s t ! m9]al breaks mu* l w9d[ glass--con*oidal fracture4 ,wide range 9 bo? transp>5cy & color4 ,transp>5t & colorless cry/all9e v>iety 7rock cry/al71 br[n transluc5t 7smoky qu>tz71 turbid :ite 7milky qu>tz71 & v>i\s color$ v>ieties 7c>nelian1 jasp]1 jet1 etc474 ,insoluble 9 acids & infusible4 ,h>dness #g4 ,specific gravity #b4f4 ,micas4--,l ! feldsp>s a gr\p ( complex silicates1 b "h *iefly ( potassium1 magnesium1 iron1 & hydroxyl4 ,abundant z rock mak]s1 ! micas are all *>act]iz$ by ! ?9ne/ & t\ghe/ ( ela/ic cleavage plates1 su* z are g5]ally kn[n z is+lass4 ,:5 a ne$le is driv5 %>ply ?r\gh a ?9 scale ( mica1 a six-ray$ puncture /> =ms ab\t ! ne$le po9t4 ,! d>k] common v>iety ( mica is ri* 9 iron & magnesium & is call$ biotite1 & ! light] color$ alkal9e v>iety1 muscovite4 ,h>dness #b4e-c4a4 ,specific gravity #b4g-c4a4 ,*lorite4--,g5]ally an intricate mixture ( m or less simil> microscopic cry/als hav+ v>y+ & r complex *emical compositions & relat$ to ! micas1 b all *>act]iz$ by a peculi> leaf gre5 color4 ,^! m9]als are a common product ( hydration wea!r+ 9 rocks :i* are ri* 9 magnesium & iron--especially ^? t conta9 biotite1 pyrox5e1 or hornbl5de 7see bel[74 ,h>dness #a-b4e4 ,specific gravity #b4e-c4 ,pyrox5es4--,an important gr\p ( relat$ rock-mak+ m9]als all ( :i* are silicates ( ! bases magnesium1 calcium1 alum9ium1 iron1 & manganese4 ,q g5]ally develop$ ei!r 9 column> or ne$le-l cry/als :i* are uni=mly %ap$ 9 cross section l ,fig4 #dhg1 #h4 ,two r imp]fect cleavages are direct$ p>allel to ! long] axis ( ! cry/al & ne>ly at "r angles to ea* o!r4 ,! colors ( all b ! lime v>ieties are d>k & g5]ally gre51 d>k br[n1 bronze1 or black4 ,! lime v>ieties are :ite1 gray1 or pale gre54 ,a d>k color$ & common iron v>iety is kn[n z augite4 ,/reak g5]ally ei!r :ite or lightly t9t$4 ,h>dness #e-f4 ,specific gravity #c4b-c4f4 ,amphiboles4--,a gr\p ( m9]als ( ! same *emical composition z ! pyrox5es1 ) :i* also 9 mo/ physical prop]ties !y agree4 ,! pr9cipal di/9ction is f\nd 9 ! %ape ( ! cross section & 9 ! cleavage 7,fig4 #dhg1 #i74 ,:]eas ! cross sections ( pyrox5es are g5]ally eight sid$1 ^? ( ! amphiboles h six sides1 & :]eas ! cleavage directions ( pyrox5es are ne>ly at "r angles to ea* o!r 7#hg71 ! simil> b mu* m p]fect cleavage directions ( ! amphiboles are incl9$ at an obtuse angle 7#abd74 ,ow+ to ! obliquity ( ! amphibole cleavage1 fractur$ surfaces ( ! m9]al appe> spl9t]y1 :i* is n 9 ! same measure true ( ! pyrox5es4 ,a fibr\s v>iety ( amphibole1 & occasionally o!r v>ieties ( ! m9]al1 is a n uncommon product ( wea!r+ ( pyrox5es4 ,o!r physical prop]ties ( ! amphiboles are 9 ! ma9 almo/ id5tical ) ^? ( ! pyrox5es4 ,g>net4--,complex alum9o-silicates or f]ro-silicates ( calcium1 magnesium1 iron1 or manganese1 or sev]al ( ^! comb9$4 ,ne>ly always 9 cry/als1 & usually f\nd 9 mica s*i/ 7see bel[74 ,! cry/als usually h twelve simil> faces1 ea* a loz5ge 7dodecah$ron71 or else tw5ty-f\r simil> faces1 or ! two =ms comb9$ 7,fig4 #dhg1 #aj74 ,brittle4 ,f any b ! gem m9]als g>net is easily di/+ui%$ by its h>dness1 :i* 9 diff]5t v>ieties ranges f some:at bel[ to some:at above t ( qu>tz4 ,! lu/] is vitre\s1 & ! color runs ! gamut ( r$s1 br[ns1 & gre5s1 b ) ! common hue d>k r$ to black4 ,/reak :ite4 ,h>dness #f4e-g4e4 ,specific gravity #c4a-d4c4 ,nephelite 7nephel5e74--,an alum9o-silicate ( sodium & potassium4 ,9 c]ta9 special prov9ces ?is m9]al is develop$ 9 abundance z an ess5tial con/itu5t ( igne\s rocks1 b else:]e practically unkn[n4 ,! r>e cry/als are hexagonal prisms 7,fig4 #dhg1 #aa71 b ! m9]al is mo/ easily det]m9$ by its g5]al resemblance to feldsp>1 b ) ! diff]5ces ( cleavage1 lu/]1 & reaction ) acid4 ,:]eas ! feldsp>s h two cleavages1 ei!r ne>ly or q p]p5dicul> to ea* o!r & ( diff]5t degrees ( p]fection1 nephelite has ?ree equal cleavages incl9$ #fj & #abj to ea* o!r & ( less p]fection ?an ei!r feldsp> cleavage4 ,! lu/] ( nephelite is p]haps ! be/ clew to its id5tity1 s9ce ?is is greasy & simulat$ by b few m9]als4 ,! f9e p[d] ( ! m9]al treat$ = "s "t ) /rong hydro*loric acid =ms a p]fect jelly ( silicic acid1 :]eas ! feldsp>s d n4 ,?\gh itself gray or :ite & unobtrusive1 nephelite is usually associat$ ) brightly color$ m9]als1 :i* are (t5 ! fir/ clew to its pres5ce 9 a rock4 ,h>dness #e4e-f4 ,specific gravity #b4e-b4f4 ,talc 7soap/one74--,a silicate ( magnesium & hydroxyl :i* is an important alt]ation product ?r\gh wea!r+ ( c]ta9 pyrox5e rocks especially4 ,usually a foliat$ mass1 ?is product is occasionally fibr\s or ev5 granul>4 ,talc is "o ( ! s(te/ ( m9]als1 hav+ a greasy feel & be+ easily scrat*$ ) ! ?umb nail4 ,! lu/] ( ! foliat$ v>ieties is apt to be pe>ly1 & ! color apple-gre5 to :ite1 ?\gh sometimes /a9$ br[n f oxide ( iron4 ,! /reak ( ! m9]al is :ite except :5 /a9$ by iron4 ,al?\gh ! rocks :i* are compos$ ma9ly ( talc 7soap/one7 are exce$+ly s(t1 !y are v t\gh & rem>kably resi/ant4 ,h>dness #a-a4e4 ,specific gravity #b4g-b4h4 ,s]p5t9e4--,l talc1 s]p5t9e is a silicate ( magnesium & hydroxyl1 & an important product ( ! break+ d[n ( magnesium m9]als 9 ! process ( wea!r+4 ,! m9]al is usually f\nd z a f9e web ( microscopic ne$le-l fib]s1 & is be/ r\ghly diagnos$ by its color & its associat$ m9]als4 ,l talc x is usually develop$ )9 ^? igne\s rocks f :i* feldsp> is lack+1 b :]e ei!r pyrox5e or oliv9e is f\nd 9 abundance or 0 previ\s to alt]ation4 ,! *>act]i/ic color ( s]p5t9e is leek-gre54 ,! rock l>gely compos$ ( s]p5t9e is call$ by ! same "n1 & be+ exce$+ly t\gh & un*ang+ is1 9 spite ( its s(tness1 a valuable build+ & ornam5tal /one4 ,a r$ magnesium g>net is apt to be associat$ ) su* s]p5t9e masses4 ,h>dness #b4e-d1 because ( impurities4 ,specific gravity #b4e-b4f4 ,/aurolite4--,a silicate ( alum9ium1 iron1 & hydroxyl4 ,f\nd 9 metamorphic rocks usually 9 association ) g>net4 ,always 9 cry/als b\nd$ by simple =ms g5]ally cross$1 z %[n 9 ,fig4 #dhg1 #ab-ad4 ,! color is d>k r$di% br[n1 & ! /reak is colorless to grayi%4 ,! h>dness is exceptional & high] ?an t ( qu>tz4 ,h>dness #g-g4e4 ,specific gravity #c4f-c4g4 ,t\rmal9e4--,an exceptionally complex silicate ( boron & alum9ium z well z iron1 magnesium1 & ! alkalies4 ,f\nd 9 metamorphic rocks & always cry/alliz$4 ,! cry/als are columns or ne$les ^: cross section is ! be/ guide to _! id5tity1 s9ce ?is is a modifi$ triangle unlike t ( any o!r m9]al 7,fig4 #dhg1 #ae-af74 ,additional diagno/ic prop]ties are ! *>act]i/ic /riations :i* run l5g?wise ( ! cry/als ^u prism faces1 & ! lack ( any cleavage 7diff]5ce f hornbl5de74 ,! h>dness is also a valuable prop]ty1 s9ce ?is is great] ?an t ( qu>tz4 ,! m9]al is brittle & ! fracture subcon*oidal4 ,! range 9 color is z great z1 or great] ?an1 t ( g>net1 ?\gh ! common =ms are jet black4 ,/reak uncolor$4 ,h>dness #g-g4e4 ,specific gravity #c-c4b4 ,oliv9e4--,a silicate ( magnesium & iron & a rock-mak+ m9]al f\nd only 9 ^? igne\s rocks :i* h little or no feldsp>4 ,x easily suff]s alt]ation by wea!r+ & passes into s]p5t9e1 & 9 fact is seldom f\nd except :5 at lea/ p>tially alt]$ to ! fibr\s webs ( t m9]al4 ,! =m ( ! unalt]$ cry/als )9 ! rocks is %[n 9 ,fig4 #dhg1 #ag1 &1 cut 9 sections1 ! m9]al appe>s 9 m or less elongat$ hexagons4 ,! h>dness ( ! unalt]$ m9]al is ab\t t ( qu>tz4 ,x has r imp]fect cleavages 9 two rectangul> directions1 & is usually transluc5t1 ) a vitre\s lu/] & a color :i* is olive-gre5 :5 n /a9$ br[n by oxide ( iron4 ,/reak uncolor$4 ,h>dness #f4e-g4 ,specific gravity #c4b-c4c4 ,,app5dix ,b ,,%ort ,,descriptions ,,( ,,"s ,,common ,,rocks ,9 ,*apt] ,,iv ! classification & ! /ructure ( rocks h be5 briefly discuss$4 ,bel[ are add$ brief descriptions ( ! m important common rocks4 ,= rocks z = m9]als x is1 h[ev]1 ess5tial t a collection ( well-*os5 specim5s be /udi$ = purposes ( comp>ison4 ,a small pocket l5s is a valuable aid 9 mak+ out ! compon5t m9]als & ! textures ( ! f9] gra9$ rocks4 #a4 ,intrusive ,rocks ,granite4--,( granitic texture1 ?\gh sometimes porphyritic z well4 ,! mo/ abundant m9]al con/itu5t is a p9k or :ite feldsp>1 usually )\t visible /riations1 ) :i* !re is usually 9 subord9ate quantity a :ite /riat$ feldsp>4 ,next 9 importance to ! feldsp> is qu>tz1 :i* because ( its lack ( cleavage %[s a peculi> gray surface resembl+ wet sug>4 ,9 addition to feldsp> & qu>tz !re is g5]ally1 ?\gh n univ]sally1 a d>k color$ m9]al1 ei!r mica or hornbl5de4 ,! mica is usually biotite1 ?\gh (t5 associat$ ) muscovite4 ,sy5ite4--,l granite1 b )\t qu>tz1 ) m /riat$ feldsp>1 & g5]ally also ! rock has a d>k] av]age t9t4 ,:ile biotite is ! commone/ d>k color$ con/itu5t ( granite1 hornbl5de is m apt to take its place 9 sy5ite4 ,less common ?an granite1 to :i* x is closely relat$ 9 orig9 & 9 composition4 ,gabbro4--,a d>k color$ rock ( granitic texture compos$ ( /riat$ feldsp> ) broad cleavage surfaces & usually an abundance ( pyrox5e4 ,9 contra/ to ! feldsp>s ( granite1 ^? ( gabbroes are (t5 dull & color$ grayi% yell[ or gre5i%4 ,! pyrox5e is (t5 9 "p *ang$ to fibr\s amphibole4 ,magnetite may be an abundant accessory m9]al4 ,diabase4--,9 color d>k l gabbro1 & ( simil> con/itution4 ,9 diabase1 h[ev]1 ! feldsp> cry/als1 in/ead ( be+ broad & ( irregul>ly int]rupt$ outl9e1 are relatively long 78la?-%ap$071 & ! pyrox5e acts z a fill] ( ! residual space betwe5 !m4 ,p]idotite4--,a heavy & d>k color$ rock ( granitic texture :i* is ne>ly or q devoid ( feldsp> b conta9s oliv9e4 ,:5 alt]$1 z x g5]ally is1 x is l>gely a mass ( s]p5t9e1 talc1 & *lorite1 surr\nd+ cores1 x may be1 ( /ill unalt]$ pyrox5e & oliv9e4 ,magnetite is an abundant con/itu5t1 & a r$ g>net is apt to be pres5t4 #b4 ,extrusive ,rocks ,obsidian4--,a rock glass ri* 9 silica4 ,x is usually black & breaks ) a p]fect con*oidal fracture4 ,x (t5 passes ov] ?r\gh ins5sible gradations into pumice1 :i* diff]s only 9 its vesicul> /ructure4 ,z reg>ds *emical composition1 obsidian & pumice are n notably diff]5t f rhyolite 7bel[74 ,rhyolite4--,a light color$ rock ( porphyritic texture1 (t5 also ) fluxion or sph]ulitic textures1 or bo? comb9$4 ,! porphyritic appe>ance is giv5 ! rock by l>ge cry/als ( a glassy1 un/riat$ feldsp> & cry/als ( qu>tz4 ,rhyolite is a v silice\s lava conta9+ r m silica ?an granite1 to :i* ( ! intrusive rocks x is mo/ closely relat$1 & f :i* x diff]s 9 its texture & 9 ! mann] ( its occurr5ce 9 nature4 ,:]eas granite is f\nd 9 great ba?olites1 laccolites1 & bysmalites1 & consolidat$ 9 mo/ cases b5ea? ! e>?'s surface1 rhyolite g5]ally occurs 9 %eets1 fl[s1 or dikes1 & consolidat$ ei!r above or 9 fissures ne> to ! surface4 ,tra*yte4--,simil> to rhyolite1 b usually ) a peculi> gray aspect f ! great] abundance ( feldsp> cry/als4 ,! rock is less silice\s ?an rhyolite1 conta9s no qu>tz cry/als1 & approa*es a feldsp> 9 its av]age composition4 ,&esite4--,simil> to rhyolite 9 appe>ance & 9 orig91 b m basic & correspond+ly d>k 9 color4 ,! porphyritic cry/als are ( la?-%ap$1 /riat$ feldsp>1 ) :i* are associat$ cry/als ( ei!r biotite or hornbl5de or bo?4 ,a fluxion texture is p>ticul>ly *>act]i/ic ( ?is type ( extrusive rock4 ,basalt4--,a d>k color$ or black basic rock ( porphyritic texture :i* diff]s b little f diabase4 ,x may %[ "u ! l5s f9e la?-%ap$ cry/als ( /riat$ feldsp> associat$ ) cry/als ( augite1 b m frequ5tly ! rock is d5se & )\t visible m9]al con/itu5ts4 ,x is p>ticul>ly likely to occur divid$ up into columns six in*es to a foot 9 diamet] & kn[n z basaltic columns4 ,especially f9e examples are kn[n f ! ,giant's ,causeway & o!r localities 9 ! we/]n ,briti% ,isles4 #c4 ,s$im5t>y ,rocks ( ,me*anical ,orig9 ,conglom]ate 78pudd+ /one074--,a rock made up f pebbles :i* are cem5t$ toge!r ) s& & f9] mat]ials4 ,! pebbles are usually worn by "w ( ! waves ^u a %ore1 & may v>y 9 size f a pea to l>ge b[ld]s4 ,!y may consi/ ( almo/ any h>d m9]al or rock1 ?\gh ! s& ab\t !m is l>gely qu>tz4 ,s&/one4--,a rock compos$ ( s& cem5t$ toge!r ei!r by calc>e\s1 silice\s1 or f]rug9\s mat]ials4 ,s&/ones are describ$ z friable :5 _! surface gra9s are easily rubb$ (f1 or z compact :5 !y are m firmly cem5t$4 ,s&/ones are (t5 di/9ctly b&$ & are sometimes v>i\sly /a9$ ) oxide ( iron4 ,^? s&/ones :i* h be5 =m$ ^u a seacoa/ are kn[n z m>9e s&/ones1 :ile ^? d]iv$ f accumulations collect$ by ! w9d 9 des]ts are di/+ui%$ z cont95tal deposits4 ,s&/ones =m mu* ?ick] =mations ?an conglom]ates1 ! latt] usually con/itut+ a basal lay] only ( ! s&/one =mation 7basal conglom]ate74 ,%ale4--,a consolidat$ mud /one :i* is probably ! mo/ abundant rock =mation4 ,9 l>ge "p clay admix$ 9 v>y+ proportions ) extremely f9e s&y gra9s4 #d4 ,s$im5t>y ,rocks ( ,*emical ,precipitation ,calc>e\s tufa 7trav]t9e74--,n to be confus$ ) tuff1 :i* is a fragm5tal extrusive or volcanic rock4 ,calc>e\s tufa is =m$ :5 wat]s :i* conta9 c>bonic acid gas & lime c>bonate 9 solution1 give (f ! gas & ) x ! p[] to hold ! lime 9 solution4 ,su* a lib]ation ( ! gas may occur :5 ! /ream is da%$ into spray above a cascade1 & ! lime is !n deposit$ ab\t ! site ( ! falls4 ,trav]t9e is g5]ally por\s & =m$ ( m or less conc5tric lay]s or incru/ations4 ,a rem>kable illu/ration is furni%$ by ! trav]t9e deposits ( ,tivoli & o!r localities ne> ,rome1 s9ce "h ! mat]ial supplies a valuable build+ /one4 ,olitic lime/one 7oolite74--,?is rock is made up ( sph]ical nodules & s has ! appe>ance ( fi% roe4 ,brok5 ap>t1 ea* gra9 reveals 9 its c5t] a core ( silice\s s& ab\t :i* c>bonate ( lime has be5 deposit$ 9 conc5tric lay]s4 ,x is ?\ght t wat]s *>g$ ) c>bonate ( lime1 9 issu+ f a riv] ne> a sea bea*1 coat ! s& gra9s ( ! latt] ) successive ?9 films ( lime c>bonate due to ! rhy?mic ebb & fl[ ( ! tides1 evaporation ( ! adh]+ wat] tak+ place :5 ! s&s are expos$ at l[ tide4 #e4 ,s$im5t>y ,rocks ( ,organic ,orig9 ,lime/one4--,a g5]ally :ite or gray rock compos$ ( c>bonate ( lime ) v>y+ proportions ( clay1 silica1 & o!r impurities4 ,! lime c>bonate is usually d]iv$ f ! h>d p>ts ( m>9e organisms1 & ! argillace\s & silice\s impurities f ! f9] l&-d]iv$ s$im5ts :i* desc5d ) !m to ! bottom4 ,dolomite 7dolomitic or magnesium lime/one74--,diff]s f lime/one 9 conta9+ v>y+ proportions ( ! m9]al dolomite 7ante1 p4 #dee71 :i* is made up ( equal p>ts ( calcium & magnesium c>bonates4 ,difficult to di/+ui% f lime/one unless a *emical te/ is made = magnesium1 ?\gh x may be said 9 g5]al t dolomite is less soluble 9 cold m9]al acids4 ,peat4--,an accumulation ( decompos$ vegetable matt] )9 small lakes & 9 lagoons sep>at$ f l>g] ones 7ante1 p4 #dbi74 ,peat repres5ts ! fir/ /age 9 ! =mation ( coal f vegetable matt]1 & diff]s f ! coals by its l>g] proportion ( conta9$ wat]4 ,because ( ?is wat] its fuel value is correspond+ly small4 ,x is usually d>k br[n or black & reveals some?+ ( ! /ructure ( ! plants out ( :i* x 0 =m$4 #f4 ,metamorphic ,rocks ,gneiss4--,a g5]ally m or less b&$ 7gneissic7 metamorphic rock ) a m9]al con/itution simil> to granite1 & (t5 develop$ by metamorphic processes f t rock4 ,x may at o!r times1 by processes n ess5tially diff]5t1 be d]iv$ f s$im5t>y =mations4 ,x usually conta9s z important con/itu5ts un/riat$ feldsp> & qu>tz1 b 9 addition x may include a /riat$ feldsp>1 biotite1 muscovite1 or hornbl5de1 or sev]al ( ^! comb9$4 ,9 proportion z mica or hornbl5de is abundant1 x has a m>k$ b&$ texture1 b x diff]s f mica s*i/ 7see bel[7 n only 9 ! pres5ce ( its feldsp>1 b 9 ! small] proportion ( mica4 ,biotite gneiss1 hornbl5de gneiss1 etc41 are t]ms us$ to designate v>ieties 9 :i* "o or ! o!r ( ! d>k color$ con/itu5ts pr$om9ate4 ,mica s*i/4--,a metamorphic rock )\t feldsp> & ma9ly compos$ ( qu>tz & light color$ mica 7muscovite74 ,! abundant mica l5ds to ! rock its *>act]i/ic s*i/ose texture1 :i* diff]s f ! usual gneissic texture4 ,9 "s cases ! mica is wrapp$ ab\t ! gra9s ( qu>tz1 b at o!r times x =ms a s]ies ( almo/ cont9u\s membranes sep>at+ lay]s ( qu>tz4 ,s]icite s*i/4--,a v>iety ( s*i/ :i* is *>act]iz$ by an abundance ( a peculi> silv]y mica ri* 9 ! elem5t gr\p hydroxyl4 ,! mica scales are (t5 microscopic & wr\ght into an intricate web ) ! qu>tz con/itu5t4 ,talc s*i/4--,a s*i/ made up l>gely ( talc1 b ) v>y+ proportions ( qu>tz1 magnetite1 etc4 ,f ! abundance ( ! talc x is usually pale gre5 or :ite4 ,*lorite s*i/4--,a gre5i%1 f9e-gra9$ metamorphic rock 9 :i* *lorite is ! pr9cipal m9]al1 b 9 :i* magnetite is a q *>act]i/ic accessory con/itu5t4 ,/aurolitic g>netif]\s mica s*i/4--,a mica s*i/ 9 :i* g>net & /aurolite are s abundant z to be ess5tial con/itu5ts4 ,clay slate4--,a metamorphos$ mud /one or %ale4 ,9 ! process ( metamorphism ! rock has be5 h>d5$1 giv5 a slaty cleavage1 & innum]able m9ute scales ( mica h develop$ to produce a silky lu/] ^u ! cleavage faces4 ,! color may be gray1 gre51 purple1 or black4 ,qu>tzite4--,a metamorphos$ s&/one 9 :i* ! s& gra9s h become enl>g$ by accretion ( silica4 ,:]eas a s&/one fractures ab\t its con/itu5t gra9s1 a break 9 qu>tzite is cont9u$ ?r\gh ! gra9s & ! cem5t alike4 ,9 contra/ to s&/ones1 ! qu>tzites d]iv$ f !m are usually light] 9 color & (t5 ne>ly :ite4 ,m>ble 7cry/all9e lime/one74--,! result ( metamorphism ^u lime/ones4 ,usually :ite 9 color b sometimes gray1 blue gray1 or yell[1 & sometimes v>i\sly brok5 or brecciat$ & /a9$ ) iron oxide4 ,eff]vesces ) cold dilute acid4 ,coals4--,"u ! head ( peat ! fir/ /age 9 ! =mation ( coals f vegetable matt] has be5 briefly describ$4 ,lignite1 or br[n coal1 repres5ts a fur!r /age & "o 9 :i* ! vegetable /ructure is /ill recognizable4 ,x is usually br[ni% black or black 9 color & conta9s a consid]able proportion ( wat]4 ,) increas$ pressure or dynamic metamorphism1 fur!r p]c5tages ( ! volatile con/itu5ts are elim9at$1 & :5 f sev5ty-five to n9ety p] c5t ( c>bon rema9s1 ! mat]ial burns ) a yell[ flame & is kn[n z bitum9\s coal4 ,?is is ! great fuel = ! production ( /eam4 ,a cont9uation ( ! metamorphic processes c>ries (f a fur!r proportion ( ! volatile matt] & leaves a d5se1 h>d1 black sub/ance ) sometimes z mu* z n9ety-five p] c5t ( c>bon4 ,?is is ! s-call$ 8h>d coal0 or an?racite g5]ally us$ = fuel 9 our h\ses1 = :i* purpose x is s well adapt$ because x burns ) a production ( mu* heat & almo/ )\t smoke4 ,,app5dix ,c ,,! ,,prep>ation ,,( ,,topographical ,,maps ,topographical maps a libr>y ( physiography4--,= ! satisfactory work+ out 9 detail ( ! geology ( any region ( complex /ructure1 an accurate topographical map is pr]equisite4 ,?is is s mu* ! m true because ne>ly all complexly fold$ or fault$ rock masses are to be f\nd 9 m\nta9\s1 or at lea/ 9 hilly regions4 ,! mak+ ( ! topographical map mu/1 !re=e1 prec$e t ( ! geological map1 & 9 mod]n usage ! latt] is a topographical & a geological map comb9$ 9 "o4 ,)9 c]ta9 n>r[ limits1 pr$ictions conc]n+ ! geological hi/ory ( a prov9ce may (t5 be made by an exp]t geologi/ f exam9ation ( an accurate topographical map4 ,j z 9 =eca/+ ! wea!r ^u ! basis ( ! usual wea!r maps1 su* pr$ictions c sometimes be made ) entire confid5ce 9 _! accuracy1 :ile at o!r times a guess only may be haz>d$4 ,! great value ( ! mod]n topographical map is becom+1 h[ev]1 univ]sally ackn[l$g$1 & e highly civiliz$ nation has ei!r complet$ or has 9 prep>ation sectional topographical maps ( its doma9 on su* a scale z is w>rant$ by its f9ancial condition & its /ate ( developm5t4 ,?us !re is n[ be+ accumulat$ a va/ libr>y ( geographical & to "s ext5t geological in=mation1 ( :i* ! /ud5t ( geology mu/ be prep>$ to make use4 ,! nature ( a cont\r map4--,m & m ! cont\r map is replac+ ! e>li] & less sci5tific me?ods ( repres5t+ topography on ! l>ge scale sectional maps1 & h5ce ?is type only ne$ "h be consid]$4 ,9 ! cont\r map1 ! relief ( ! l& is repres5t$ by a s]ies ( curv+ l9es1 ea* ! int]section ( a p>ticul> horizontal plane ) ! l& surface1 & ! sev]al planes sep>at$ by uni=m diff]5ces ( elevation4 ,?is altitude int]val is kn[n z ! cont\r int]val4 ,its *oice is a matt] ( consid]able importance1 = ?\gh regions ( relatively simple topography may be adequately repres5t$ ^u a map ( l>ge cont\r int]val1 say "o hundr$ feet1 ano!r di/rict may require an int]val z %ort z five feet4 ,a cont\r map ) ?is int]val may be conceiv$ to h be5 made by flood+ ! region :i* x repres5ts & prep>+ maps ( ! %ore l9es = ea* rise ( five feet ( ! wat] surface1 & sup]impos+ ! sev]al maps ?us d]iv$ ) accurate regi/ration "o above ! o!r4 ,:]ev] ! l& slopes are /eep1 ! %ore l9es ( ! sev]al maps w be cr[d$ closely toge!r & give ! effect ( a relatively d>k local %ade2 :]e1 ^u ! o!r h&1 ! surface is relatively flat1 ! sev]al %ores w be widely spac$ & ! effect w be to produce a :ite area ^u ! map4 ,?us 9 cont\r maps d>k tones indicate /eep gradi5ts & pale tones a flatness ( surface4 ,! selection ( scale & cont\r int]val4--,) ! use ( ! small scale 9 ! cont\r map1 ! tones ( ! map w be correspond+ly d>k1 ?\gh ! relative diff]5ces 9 tone w rema9 ! same4 ,) ! use ( a clos] cont\r int]val ! tones w deep5 ?r\gh\t4 ,! adju/m5t ( scale & cont\r int]val to any giv5 region is a matt] requir+ exp]i5ce 9 topographical mapp+1 & 9 addition a k ( ! geological significance ( topographic features4 ,un=tunately1 ! elem5t ( exp5se & ! special comm]cial objects held 9 view1 conspire to select scales & cont\r int]vals :i* are (t5 little adapt$ to ! di/ricts survey$4 ,! me?od ( prep>+ a topographical map4--,hav+ fix$ ^u ! scale & ! cont\r int]val :i* is to be employ$1 ! task ( ! topographical surveyor is next to fix accurately ! positions & ! elevations ( a suffici5t numb] ( po9ts to control ! map1 & !n to hang1 z x 71 ^u ^! po9ts z atta*m5ts ! design repres5t$ by ! relief4 ,7 ! surface ( ! gr\nd to be repres5t$ by a flexible fabric1 ! map mak] might raise f a flat base a s]ies ( /\t po/s ( ! heights & 9 ! positions :i* he has det]m9$1 & ^u ^! supports arrange ! slopes ( ! fabric mu* z drap]y is adju/$4 ,! det]m9ation ( ! exact positions & ! elevations ( 8 control /ations is1 !re=e1 a process coldly precise & =mal2 :]eas 9 ! %ap+ ( ! surfaces 8 att5tion %\ld be fix$ m ^u correctly reproduc+ ! %apes ?an ^u fix+ accurately ! position ( e po9t4 ,z a matt] ( fact1 ! position ( ! av]age po9t w be mo/ accurately fix$ :5 ! %apes ( ! features are mo/ cle>ly compreh5d$4 ,to "s ext5t1 !re=e1 ! topograph] %\ld be famili> ) ! geological significance ( ! e>? features :i* he is repres5t+4 ,laboratory ex]cises 9 ! prep>ation ( topographical maps4--,! pr9ciples :i* und]lie ! surveyor's me?od = prep>+ a topographical map may be le>n$ 9 ! laboratory by ! use ( models & ! simple device %[n 9 plate #bd ,a & ,b4 ,to repres5t ! section ( c\ntry to be mapp$ a model 9 pla/] ( ,p>is is sub/itut$1 & ?is is plac$ )9 a rectangul> tank to :i* locat+ c>riages & altitude gauges are atta*$ t all[ ! /ud5t to fix ! position & ! elevation ( any po9t ^u ! surface ( ! model4 ,,plate #bd4 ,illu/ration3 ,a4 ,app>atus = ex]cise 9 ! prep>ation ( topographic maps4 ,illu/ration3 ,b4 ,! same app>atus 9 use = te/+ ! cont\rs ( a map4 ,illu/ration3 ,c4 ,model+ app>atus 9 use4 ,^u ea* model ! /ud5t 8locates01 or fixes1 ! position ( a suffici5t numb] ( po9ts = ! control ( 8 map1 ent]+ ^u an appropriate map base = ea* position ! altitude :i* 0 read f ! gauges4 ,n[ ) ! map always be=e him he 8sket*es 90 ! =ms ( ! surface by means ( cont\r l9es4 ,= ?is purpose x is (t5 desirable to fix r\ghly ! direction ( ! /eepe/ slope at a numb] ( places1 & not+ ! diff]5ces 9 elevation betwe5 control /ations1 divide up ! di/ance 9 accordance ) ! curves ( slope & />t ! cont\rs at "r angles to ! slope4 ,aft]w>ds su* sections are connect$ by sket*+ 9 ) ! model always 9 view = control 7,fig4 #dhh74 ,illu/ration3 ,,fig4 #dhh4--;,a /ud5t's map prep>$ f a model by ! use ( ! cont\r app>atus repres5t$ 9 plate #bd ,a4 ,! v]ification ( ! map4--,! map prep>$1 its accuracy may be te/$ by a simple me?od :i* is d5i$ ! topograph] :o has to d ) ! actual surface ( ! gr\nd4 ,! locat+ c>riages & altitude gauges are remov$ f ! tank1 :i* is next fill$ ) wat] & level$ by means ( guide m>ks ^u ! int]ior4 ,a few drops ( milk or ( ord9>y clo!s blue+ are add$ to ! wat] to r5d] x opaque1 & x is !n drawn (f at ! faucet 9 successive in/allm5ts1 s t ! surface drops by lay]s correspond+ 9 ?ickness to ! cont\r int]val ( ! map1 plate #bd ,b4 ,z ea* lay] is )drawn1 t cont\r ( ! map to :i* ! %ore l9e %\ld correspond is c>efully exam9$ & correct$4 ,by su* corrections ! nature ( ! fir/ errors made is soon appreciat$1 & ! me?od ( proc$ure is ?us m easily acquir$4 ,at ! same "t ! significance ( ! design ( ! map is m quickly le>n$ ?an by a m]e exam9ation ( ! /&>d gov]nm5t maps4 ,! "w above outl9$ calls = wat]pro($ models ( suitable =m & size1 & a s]ies1 ea* ( :i* sets =? "s typical feature or s]ies ( features1 has be5 design$ by ,mr4 ,irv+ ,d4 ,scott4#b ,! prep>ation ( physiographic models4--,! app>atus us$ to prep>e ! topographic map is adapt$ also = prep>+ a physiographic model f a /&>d topographical map4 ,= ?is purpose ! me?od is ess5tially rev]s$1 ?\gh ! tank is replac$ to advantage by a light metal frame elevat$ ^u "o side s z to p]mit a free use ( ! h&s 9 model+ ! clay4 ,! mat]ial us$ 9 prep>+ ! model is arti/s' model+ clay#c :i* has a base ( beef suet1 & h5ce does n dry out & crack z does ord9>y clay4 ,its =m is1 !re=e1 reta9$ indef9itely1 & x may be us$ aga9 & aga94 ,mo/ maps mu/ be enl>g$ 9 model+1 & ! simple/ way is (t5 to photographically or by pantograph enl>ge ! map to ! scale ( ! model4 ,! map prep>$1 x is cov]$ by a ?9 celluloid plate :i* has cut ^u x a s]ies ( cross$ l9es spac$ 9 in*es & l>g] subdivisions to correspond to ^? ( ! locat+ c>riages 7plate #bd ,c74 ,! enl>gem5t ( ! map is n ess5tial to exp]i5c$ work]s1 & ! /&>d map may be cov]$ 9 simil> mann] by a transp>5t plate ) 8*eck]bo>d0 design1 ! squ>es ( :i* be> "s simple relation 9 size to ! l>g] divisions ( ! locat+ c>riages 7,plate #bd ,c1 re>74 ,! me?od ( prep>+ ! model is comp>atively simple4 ,beg9n+ at any po9t ^u ! map1 ! int]section ( a heavy cont\r l9e ) "o ( ! guide l9es ( ! celluloid 8position plate0 is c>efully not$4 ,bo? ! position & ! elevation ( ?is po9t are fix$ by ! po9t ( ! altitude gauge ( ! model+ frame1 & ! clay built up b5ea? x to t height4 ,) ! f+]s ! clay is n[ r\ghly %ap$ 9 v>i\s directions f ?is po9t1 ! altitude gauge is advanc$ by ! locat+ c>riage s z to correspond 9 position to ! int]section ( ! next heavy cont\r l9e ) ! same guide l9e ( ! position plate1 & ! elevation = ?is po9t simil>ly adju/$ ^u ! model4 ,z be=e1 ! surface ( ! clay is r\ghly %ap$ 9 advance & ^u ! sides s z to con=m to ! indications ( ! map2 & ?is process is repeat$ until ! "w is f9i%$4 ,corrections = int]m$iate positions may be c>ri$ to any desir$ degree ( ref9em5t :i* ! scale & ! accuracy ( ! map p]mit4 ,models :i* are l>g] ?an ! area ( ! model+ frame are prep>$ by mak+ a squ>e foot at a "t by ! above describ$ process1 & !n mov+ ! frame =w>d & adju/+ 9 a new position by means ( ! %>p p9s 9 ! legs ( ! app>atus4 ,,read+ ,,ref]5ces ,,william ,h4 ,,hobbs1 ,new ,laboratory ,me?ods = ,in/ruction 9 ,geography1 ,j\rnal ( ,geography1 vol4 #g1 #aiji1 pp4 #ig-ajd4 ,also ,scot4 ,geogr4 ,mag41 vol4 #bd1 #aijh1 pp4 #fdc-feb4 ,! ,model+ ( ,physiographic ,=ms 9 ! ,laboratory1 ibid41 vol4 #h1 #aiaj1 pp4 #bbe-bbh4 ,,app5dix ,d ,,laboratory ,,models ,,= ,,/udy ,,9 ,,! ,,int]pretation ,,( ,,geological ,,maps ,illu/ration3 ,,fig4 #dhi4--,models to repres5t outcrops ( rock4 ,! laboratory models :i* h be5 describ$ on page #fc1 & are us$ to repres5t outcrops 9 ! /udy ( geological maps1 are %[n 9 ,fig4 #dhi4 ,! drum-%ap$ blocks s]ve to repres5t massive rocks :i* occur 9 irregul>ly %ap$ masses su* z ba?olites & fl[s4 ,! long1 n>r[ /rips are = intrusive rocks 9 ! =m ( dikes1 :ile ! l>g] blocks provid$ ) a swivel jo9t are us$ = outcrops ( s$im5t>y rocks1 & aft] adju/m5t !y give ! dip & /rike ( ! exposure4 ,! w+ bolts us$ 9 _! con/ruction %\ld be ( bronze1 because ( ! effect ( iron ^u ! compass4 ,= ! same reason tables %\ld n be plac$ ne> iron beams or columns4 ,all ^! blocks c be made by an ord9>y c>p5t]1 & %\ld be available 9 suffici5t numb]s to arrange problems l ^? ( ,figs4 #dg1 #dh1 & #dij4 ,) a view to supply+ sugge/ions = o!r problems ( ! same g5]al nature1 ! ?ree additional field maps ( ,fig4 #dia h be5 introduc$4 ,illu/ration3 ,,fig4 #dij4--,special laboratory table set ) a problem 9 geological mapp+ :i* is solv$ 9 ,figs4 #dg & #dh4 ,illu/ration3 ,,fig4 #dia4--,?ree field maps to be us$ z sugge/ions 9 arrang+ laboratory tables = problems 9 ! prep>ation ( areal geological maps4 ,! li/ ( que/ions giv5 bel[ is int5d$ to indicate ! nature ( "s ( ! problems :i* ! /ud5t %\ld be ask$ to solve 9 ! prep>ation ( ea* map4 ,! numb]s 9 p>5!ses ref] to pages 9 ?is book :]e fur!r in=mation is giv53-- ,,/ratigraphical #a4 ,( ! =mations repres5t$ :at ones are s$im5t>y & :at igne\s 7,*ap4 ,,iv1 ,app4 ,b78 #b4 ,:i* =mations1 if any1 are sep>at$ by uncon=mities 7#ea-ec78 #c4 ,:at is ! ord] ( age ( ! s$im5t>y =mations 7#fe78 #d4 ,:at are ! expos$ ?icknesses ( ea* ( ^! =mations 7#dh-di78 #e4 ,d any ( ^! values repres5t full ?ickness ( ! =mation1 & if s1 :i* ones8 #f4 ,:at is ! age 9 t]ms ( ! s$im5t>y =mations ( ea* ( ! igne\s rock masses 7#fe78 #g4 ,:i* igne\s rocks1 if any1 occur 9 ba?olites 7#adc1 #dda78 ,:i*1 if any1 9 dikes 7#adj78 ,,/ructural #h4 ,:at =mations1 if any1 h monocl9al dip 7#db78 #i4 ,indicate ^u ! map by da%$ l9es ! cre/s ( all anticl9es & ! tr\gh l9es ( syncl9es4 #aj4 ,indicate by arr[s ! direction ( pit* ( all plung+ anticl9es & syncl9es :]ev] disclos$ by *anges ( dip & /rike 7#dc74 #aa4 ,indicate ! approximate position ( all faults ^: position is disclos$ 7#eh-fa71 &1 if possible1 /ate :i* limb is ! "o d[n?r[n4 #ab4 ,prep>e suitable geological sections4 ,,read+ ,,ref]5ce ,,william ,h4 ,,hobbs4 ,app>atus = ,in/ruction 9 ,geography & ,/ructural ,geology4 ,,iii4 ,! ,int]pretation ( ,geologic ,maps4 ,s*ool ,sci5ce & ,ma!matics1 vol4 #i1 #aiji1 pp4 #fdd-fec4 ,,app5dix ,e ,,sugge/$ ,,it9]>ies ,,= ,,pilgrimages ,,to ,,/udy ,,e>? ,,features ,! *ief value ( ! laboratory /udies discuss$ 9 ! prec$+ app5dices is z a prep>ation = obs]vations made 9 ! field--! laboratory p> excell5ce ( ! geologi/4 ,! pilgrimages ^: it9]>ies are "h sugge/$ h be5 plann$ especially = impress+ by obs]vation ! lessons ( ?is book4 ,su* j\rneys are be/ int]rupt$ at a relatively small numb] ( localities :i*1 because already /udi$ 9 "s detail1 are specially adapt$ to s]ve z c5t]s = local excursions4 ,^! localities w 9 mo/ cases be ! great sc5ic places to :i* t\ri/s resort1 or ! seats ( univ]sities ne> :i* specially detail$ explorations h be5 (t5 made4 ,)9 ! ,unit$ ,/ates a few local geological guides h be5 publi%$1 & ! ,geologic ,folios publi%$ by ! ,unit$ ,/ates ,geological ,survey are already available = a numb] ( su* c5t]s4 ,= "o long geological pilgrimage we are =tunate 9 hav+ a c>efully prep>$ guide1 namely1 f ,new ,york to ! ,yell[/one ,national ,p>k & back1 ) a side trip to ! ,gr& ,caon ( ! ,colorado4 ,except = ! side trip ?is r\te1 9 l>ge measure1 corresponds ) "o "h *os51 & = ! return j\rney especially ! /ud5t is ref]r$ to x = in=mation 7,geological ,guide ,book ( ! ,rocky ,m\nta9 ,excursion1 edit$ by ,samuel ,frankl9 ,emmons4 ,comte ,r5du de la ,congrs ,gologique ,int]nationale1 #eme ,session1 ,wa%+ton1 #ahia1 #ahic1 pp4 #bec-dhg1 map & plates #ac1 figs4 #cb74 ,our j\rney is begun at ,new ,york ,city1 :i* is built ab\t ! deeply subm]g$ *annels ( an e/u>y *ok$ ) glacial deposits1 ?\gh ! *annel may be foll[$ z a deep caon across ! cont95tal %elf to its m>g9 7#beb1d pl4 #ag ,b74 ,new ,york ,city is also ^u ! m>g9 ( ! glaciat$ area1 ! out] t]m9al mora9e ( :i* is well repres5t$ on ,long ,isl& 7#bih74 ,across ! ,hudson 9 ,new ,j]sey is ! great ,coa/al ,pla9 :i* meets ! oldl& 9 a well-def9$ m>g9 7#aei1 #bdf1 #bdg74 ,a local geological guide ( ! vic9ity ( ! metropolis has be5 writt5 by ,gratacap 7,geology ( ! ,city ( ,new ,york1 ,great] ,new ,york4 ,br5tanos1 ,new ,york1 #aijd1 pp4 #aai1 pls4 & map74 ,travel+ by ! ,new ,york ,c5tral ,railway1 we foll[ up ! ,mohawk outlet ( ! glacial lakes ,iroquois & ,algonqu9 7#ccd71 fir/ skirt+ ^u ! ea/ ! great sills ( intrusive basalt kn[n z ! ,palisades1 ) _! m>k$ly column> jo9t+ & int]sections by num]\s faults4 ,above ,peekskill we ent] ! picturesque n>r[s ( ! riv] 7#agd71 cut 9 ! h>d cry/all9e rocks ( ! ,highl&s4 ,ent]+ ! ,mohawk ,valley1 we pass ,syracuse ) lime/one cav]ns & well-ori5t$ jo9ts wid5$ by solution ?r\gh ! ag5cy ( ! desc5d+ gr\nd wat] 7#aha1 pl4 #f ,b74 ,a bran* l9e to ! s\?we/ rea*es ! vic9ity ( ,cayuga ,lake & ,i?aca1 :]e are well-ori5t$ jo9ts :i* h controll$ ! dra9age directions1 & !re is also a typical /ra? 7#ee1 #hg1 #dbh74 ,to ,niag>a ,falls at lea/ a day %\ld be allott$ = ! 8gorge ride0 by trolley c>1 ?us mak+ ! complete circuit ( ! br9k ( ! gorge ) int]ruptions & local /udies at all important po9ts 7#ceb-cff1 pl4 #bc ,a74 ,f ,niag>a ,falls ov] ! ,mi*igan ,c5tral ,railway we rea* ,detroit on ! pres5t outlet ( ! upp] ,great ,lakes z well z ( ! lat] ,lake ,algonqu9 7#ccd74 ,f ?is city z a c5t] a trip is made by electric railway to ,ypsilanti & ,ann ,arbor1 across ! bottoms ( ! e>ly glacial lakes f ! fir/ ,maumee to ,w>r5 7#ccj-ccc74 ,! /rong ,:ittlesey bea* is enc\nt]$ at ! little /ation ( ,ridge ,road1 & "o ( ! ,maumee bea*es on ,summ] ,/reet 9 ,ypsilanti4 ,! city ( ,ypsilanti is built ^u a t]race 7#afe7 ( ! ,huron ,riv]1 & ano!r t]race 9 ! same s]ies is cross$ by ! electric l9e4 ,9 an excursion ( a few miles d[n ! riv]1 pass+ me&]s 7#afd-afe7 & ox-b[ lakes 7#afe1 #dae71 is f\nd an int]e/+ case ( /ream capture ne> ! little village ( ,rawsonville 7#age4 ,see ,isaiah ,b[man1 ,j\r4 ,geol41 ,vol4 #ab1 #aijd1 pp4 #cbf-ccd74 ,cont9u+ our j\rney f ,ypsilanti ov] a high mora9e 7#cab71 ,ann ,arbor is rea*$1 built ^u ! level pla9 ( outwa% ) fosses sometimes sep>at+ x f ! mora9e 7#bha1 #cad74 ,^u ! campus ( ! univ]sity are great b[ld]s ( jasp] conglom]ate & jaspilite1 :i* 7 transport$ f ! nor? by ! cont95tal glaci] 7#cje74 ,across ! riv] f ! ,mi*igan ,c5tral /ation & beh9d ! little *ur* is a delta =m$ 9 "o ( ! glacial lakes ,maumee & "h op5$ 9 section 7#afh74 ,we/ ( ! city is a great valley :i* 0 ! =m] c\rse ( ! ,huron ,riv] :5 ?us div]t$ by ! cont95tal glaci] ly+ to ! ea/w>d ( ,ann ,arbor--bord] dra9age 7see ,ann ,arbor folio by ! ,u4 ,s4 ,g4 ,s41 &1 fur!r1 ,r4 ,c4 ,all5 & ,i4 ,d4 ,scott1 ,an ,aid to ,geological ,field ,/udies 9 ! ,vic9ity ( ,ann ,arbor1 ,george ,wahr1 publi%]1 ,ann ,arbor74 ,return+ to ,detroit 7,m4 ,c4 ,ry471 ! great ,sibley qu>ries 9 lime/one ne> ,tr5ton may be visit$4 ,!y display p]fect jo9t+1 num]\s fossils1 & especially well-glaciat$ surfaces int]rupt$ by deep tr\ghs & %[+ /ri ( sev]al glaciations 7#cjd74 ,f ,detroit ! j\rney is cont9u$ by /eam] to ,mack9ac ,isl& 9 ! /rait connect+ ,lakes ,mi*igan & ,huron1 pass+ on ! way ?r\gh ! peculi> delta ( ! ,/4 ,clair ,riv] 7#dca71 & com+ 9 view ( ! not*$ headl&s1 :i* are a monum5t to ! po/-glacial uplift ( ! glaciat$ area 7#bej1 #cda74 ,a day is sp5t at ,mack9ac ,isl& & ,/4 ,ignace 9 ord] to /udy ) "s c>e ^! uplift$ /r&s ( ! late glacial lakes 7#cda-cdd74 ,*icago may n[ be rea*$ ei!r by /eam] or by rail1 & 9 its vic9ity we may see ! elevat$ bea*es & ! anci5t outlet ( ,lake ,*icago 7#cca-ccb1 #cdg1 pl4 #bb ,a4 ,see ,*icago ,folio1 ,u4 ,s4 ,g4 ,s474 ,by ! ,*icago & ,nor?we/]n ,railway ! area ( recessional mora9es & int]m$iate outwa% pla9s1 & lat] t ( ! druml9s1 are cross$ 9 j\rney+ to ,madison1 ,wiscons94 ,by exam9ation ( ! maps on pages #cjh & #cag 9 connection ) ! l>g] scale atlas %eets ( ! ,unit$ ,/ates ,geological ,survey 7,janesville1 ,evansville1 & ,madison %eets71 ?is c> j\rney c be made mo/ in/ructive 9 ga9+ famili>ity ) ! *>act]i/ic glacial features1 & ?is /udy is cont9u$ to special advantage 9 excursions ab\t ,madison z a c5t] 7#caf-cag1 #djg74 ,?is is ! m true s9ce at num]\s localities 9 ! vic9ity ( ,madison ! well-/riat$ glaci] pavem5t is expos$ = comp>ison ( ! /ri z reg>ds direction ) ! axes ( ! sev]al types ( glacial features4 ,an especially in/ructive excursion may be made by c>riage 9 a s+le day to ! 8driftless area0 "s twelve miles we/ ( ! city4 ,be=e rea*+ x we cross 9 alt]nation a s]ies ( recessional t]m9al mora9es 7pl4 #ag ,c7 & outwa% pla9s1 & ne> ,cross ,pla9s enc\nt] ! p>tially dissect$ upl& ) its arboresc5t dra9age & ev5 sky l9e 7#bih1 #cjj-cja1 #cab-cac1 pl4 #af ,a & ,b74 ,typical %ore =mations 7#bcc1 #bda1 #bdb7 are /udi$ to advantage ab\t ,lake ,m5dota 9 a walk+ trip to & beyond ,picnic ,po9t1 :]e are f\nd ! be/ ice ramp>ts 7#dca-dcd4 ,see ,buckley1 ,trans4 ,wis4 ,acad4 ,sci41 ,vol4 #ac1 pp4 #ada-afb1 pls4 #ah74 ,our j\rney is n[ cont9u$ ov] ! ,*icago & ,nor?we/]n ,railway to ,devils ,lake ne> ,b>aboo1 :]e we cross a sali5t ( ! driftless area1 )9 :i* lies ,devils ,lake1 imprison$ 9 a =m] valley ( ! ,wiscons9 ,riv]1 s9ce div]t$ to ano!r c\rse z a result ( ! glacial invasion 7#cab-cac74 ,! valley "h is a =m] n>r[s 9 h>d qu>tzite 7#dff71 :i* t[]s above ! lake 9 un/able *imneys 7#cjj71 su* z ! ,devils ,t[]1 b su* remnants are n f\nd on ! o!r side ( ! mora9e1 be+ !re replac$ by r\nd$ rock %\ld]s4 ,j nor? ( ! lake ! m>g9al mora9e :i* blocks ! valley is s *>act]i/ic z to m]it special /udy 7pl4 #ag ,c74 ,only a few miles nor?w>d along ! railway f ,devils ,lake is ,ableman1 :]e1 expos$ 9 a high cliff1 ! h>d purple qu>tzite ) beautiful ripple m>ks to reveal its plane ( s$im5tation 7pl4 #aa ,a7 dips v]tically1 & is ov]la9 by horizontally b$d$ yell[ s&/one4 ,! m>k$ angul> uncon=mity :i* is ?us display$ is fur!r made evid5t by a basal lay] ( conglom]ate 7#dfc7 9 ! s&/one 7#ea-ec74 ,"h also are deposits ( loess along ! riv]1 :i* display _! v]tical jo9t surfaces 7#bjg74 ,an excell5t geological guide to ?is int]e/+ di/rict & t ( ! neighbor+ 8,dalles0 ( ! ,wiscons9 ,riv] has be5 writt5 by ,salisbury & ,atwood 7,! ,geography ( ! ,region ab\t ,devils ,lake & ! ,dalles ( ! ,wiscons91 etc41 ,bull4 #e1 ,wis4 ,geol4 & ,nat4 ,hi/4 ,surv41 #aijj1 pp4 #aea1 pls4 #ch1 figs4 #dg74 ,if we h tak5 a conveyance at ,devils ,lake = ,ableman1 we may cont9ue 9 ! same mann] to ,kilb\rn1 :]e beg9 ! picturesque ,dalles ( ! ,wiscons9 ,riv]--"h a "y gorge cut 9 s&/one1 because ! ,wiscons9 0 div]t$ f its old valley to bord] dra9age at ! edge ( ! driftless area 7#cjj1 #cba74 ,! side caons ( ! riv]1 ?r\gh _! abrupt zigzags1 reveal ! control ( _! c\rses by ! jo9t sy/em 7#bbd74 ,9 ! j\rney up ! rapids by /eam] to inspect ! ,dalles1 we obs]ve _m beautiful examples ( cross b$d+ 9 ! s&/one 7#cg74 ,f ,kilb\rn we cont9ue our j\rney to ,m9neapolis ov] ! ,*icago1 ,milwaukee1 & ,/4 ,paul ,railway1 & ne> ,camp ,d\glas are ov] a p5epla91 out ( :i* rise prom95t monadnocks 7#aga74 ,at ,la ,crosse ! ,mississippi ,riv] is rea*$1 fl[+ b5ea? bluffs ( s&/one :i* are capp$ by loess 7#bjg74 ,! me&]+s & ! num]\s cut-(fs ( ! ,mississippi may be obs]v$ to ! left 7#dae74 ,lake ,pep9 is a side-delta lake block$ by ! deposits ( ! ,*ippewa ,riv] 7#dai74 ,f ,m9neapolis an excursion is made to ,=t ,snell+ to view ! "y gorge ( ! ,mississippi1 cut by ! ,falls ( ,/4 ,an?ony = a di/ance ( ab\t eight miles 9 mann] simil> to t ( ! sev5 miles ( ,niag>a gorge 7#ced71 & to comp>e ?is n>r[ gorge ) ! broad valley ( ! ,w>r5 ,riv] :i* dra9$ ,lake ,agassiz 7#cbg74 ,some:at f>!r up ! ,w>r5 ,riv] are examples ( sauc] lakes 7#daf74 ,f ,m9neapolis ! j\rney may be cont9u$ by ! ,great ,nor!rn ,railway to ,liv+/on1 ,montana1 ?us cross+ betwe5 ! /ations ( ,muscoda & ,buffalo ! b$ ( ,lake ,agassiz & its m>g9al bea*es 7#cbe-cbh4 ,= local geology ( ,m9nesota consult ,c4 ,w4 ,hall1 ,geology ( ,m9nesota1 ,vol4 #a1 ,m9neapolis1 #aijc74 ,! ,yell[/one ,p>k is ent]$ f ,liv+/on 7,liv+/on ,geological ,folio1 ,u4 ,s4 ,g4 ,s47 & dep>ture f x made at ! relatively new ,union ,pacific t]m9al at ! s\?we/ m>g94 ,! regul> trip ?r\gh ! ,p>k includes visits to ! sev]al geys] bas9s 7#aia-aid71 ,obsidian ,cliff 7#cc1 #dfc71 ! ,caon ( ! ,yell[/one1 etc4 ,good climb]s c make a side trip f ne> ! ,mammo? ,hot ,spr+s to ! top ( ,quadrant ,m\nta91 ! remnant ( a 8biscuit cut0 upl& 7#cgb71 & !re /udy ! nivation process 7#cfh1 ,yell[/one ,national ,p>k ,folio1 ,u4 ,s4 ,g4 ,s474 ,! trip f ! ,p>k to ,salt ,lake ,city1 ov] ! ,union ,pacific ,railway1 passes ?r\gh ! ,r$ ,rock ,pass1 ! =m] outlet ( ,lake ,bonneville 7#dbc71 into ! des]t ( ! ,great ,bas9 7,*aps4 ,,xv & ,,xvi74 ,great ,salt ,lake is a sal9e lake or s9k ) an int]e/+ record ( climatic *anges 7#aih1 #dja74 ,! front ( ! ,wasat* ,range1 9 view & easily rea*$ f ,salt ,lake ,city1 is deeply scor$ by ! horizontal %ore t]races ( ,lake ,bonneville 7#aih1 #aii71 & ^! t]races are ext5d$ at e rentrant by b>ri] bea*es ( great p]fection4 ,9 ! ,plei/oc5e p]iod m\nta9 glaci]s 9 "p occupi$ ! valleys ( ?is range1 ?\gh !y did n always ext5d z f> z ! m\nta9 front4 ,big ,cottonwood ,caon1 :i* realizes ?is condition1 & ! neighbor+ ,little ,cottonwood ,caon1 f ^: front its glaci] spread into an exp&$ foot 7#bfd71 ?us %[ = comp>ison 9 a s+le view ! ,v & ! l[ ,u sections respectively 7#agb1 #cgf74 ,"h are also alluvial fans 7#bac7 & rec5t faults :i* int]sect !m4 ,f ,salt ,lake ,city ! return to ,new ,york may be made by ! ,d5v] & ,rio ,gr&e ,railway across des]ts & ?r\gh ! ,royal ,gorge1 ! caon ( ! ,arkansas ,riv]4 ,a full it9]>y ( ! po9ts ( geological int]e/ along ?is r\te1 & cont9u$ to ,*icago1 ,wa%+ton1 & ,new ,york1 is suppli$ 9 mu* detail 9 ! guide ( ! geological excursion to ! ,rocky ,m\nta9s above cit$4 ,?is ! travel+ geologi/ %\ld n fail to /udy4 ,"s ref]5ces to po9ts along ?is j\rney w be f\nd on prec$+ pages ( ?is book 7#bai-bbj1 ,high ,pla9s2 #agj1 ,allegh5y ,plateau 9 ,we/ ,virg9ia2 #agf1 wat] gap ( ,h>p]'s ,f]ry2 #agf-agg1 #ahd-ahf1 side trip up ! ,%5&oah ,valley to ,luray ,cav]ns & ,snick]s ,gap2 #bea1 ,*esapeake ,bay74 ,in/ead ( return+ directly f ,salt ,lake ,city1 ! travel]1 if he has suffici5t "t at 8 disposal1 may ext5d 8 j\rney s\?we/w>d across ! ,great ,bas9 to ,los ,angeles4 ,a bran* l9e f ?is r\te leaves ! ,vegas ,valley & passes )9 rea* ( ! fam\s ,dea? ,valley 7#bja7 to ,tonopah 7#gi7 & ! ,ow5s ,valley 7#gg-gh1 #ib71 :]e are _m surface faults dat+ f ! e>?quake ( #ahgb & o!r less rec5t di/urbances4 ,return+ to ! junction po9t1 ! r\te cont9ues across ! ,colorado & ,mohave des]ts to ,los ,angeles4 ,f ,los ,angeles z a c5t] ! exceptionally int]e/+ t]races1 caves1 & /acks ( an uplift$ coa/ are to be se5 to be/ advantage ne> ,pt4 ,h>=d 7,*ap4 ,,xix74 ,! isl&s ( ,san ,clem5te & ,santa ,catal9a may also be rea*$ f ,los ,angeles 7#bci1 #bdh1 #bdi1 #bej1 #bef1 #beg1 pls4 #e ,b1 #g ,a1 #ab ,a74 ,! return to ! ,ea/1 if made by ! ,santa ,fe ,railway1 p]mits ( a visit to ! ,gr& ,caon 7#agd1 #ddc7 f ! /ation ( ,williams4 ,f t po9t ea/w>d ! geology ( ! r\te is fully cov]$ 9 ,emmons' ,guide to ! ,rocky ,m\nta9 ,excursion already cit$4 99 99 99 99 99 ,= ! b5efit ( ^? :o are privileg$ to travel 9 ,europe1 & ! numb] increases ye>ly1 a pilgrimage is sugge/$ :i* may easily be made to correspond ) plans laid out on ! basis ( hi/orical1 arti/ic1 & sc5ic po9ts ( int]e/4 ,! only popul> guide ( a g5]al nature writt5 = geologi/s travel+ abroad appe>s to be a brief b valuable little pap] by ,pr(essor ,lane 7,! ,geological ,t\ri/ 9 ,europe1 ,popul> ,sci5ce ,mon?ly1 ,vol4 #cc1 #ahhh1 pp4 #baf-bbi74 ,! publi%+ h\se ( ,gebrd] ,borntrg] 9 ,b]l9 is n[ publi%+ a q valuable s]ies ( geological guides deal+ ) special di/ricts & writt5 by well-kn[n au?orities 7,sammlung ,geologis*] ,fhr]74 ,( ?is s]ies "s ?irte5 numb]s h already be5 issu$4 ,_m o!r valuable local guides ( a geological nature are ! ,livrets ,guides ( ! ,int]national ,geological & ,geographical ,congresses1 & ! simil> pamphlets suppli$ 9 connection ) annual meet+s ( national or prov9cial geological societies4 ,pass5g]s on /eam%ips sail+ f ! h>bor ( ,new ,york pass out ov] a deeply subm]g$ caon 7#beb7 l>gely fill$ ) glacial deposits1 ?r\gh ! ,n>r[s 7#agd71 & 9 sight ( ,s&y ,hook1 a modifi$ spit 7#bch1 #bdj74 ,to ! left are se5 ! great mora9ic accumulations at ! bord] ( ! glaciat$ area on ,long ,isl& 7#bih74 ,9 ! c\rse ( ! trans-,atlantic voyage a mu*-r\nd$ iceb]g may be enc\nt]$ 7#bia71 ?\gh ?is is mu* m apt to occur ^u ! nor!rn r\tes f ,quebec1 & late 9 ! season4 ,^u ent]+ ! ,engli% ,*annel ! l& on bo? coa/s rises 9 /eep cliffs1 :]e are f\nd all ! common %ore features well develop$ 7,*ap4 ,,xviii74 ,! ,g]man /eam%ips pass 9 sight ( ,heligol&1 t la/ remnant ( wave erosion 7#bcf74 ,:ile travel+ 9 ,europe1 ! /ud5t %\ld consult a map ( ! glaciat$ area 7#bii71 & s le>n to recognize its peculi>ities1 & c>efully m>k its m>g9al mora9e 7#caa7 & o!r /rongly m>k$ features4 ,if ! ,briti% ,isles are visit$ & ! m rugg$ areas are select$1 "o may /udy ! cirques & o!r *>act]i/ic features due to ! pres5ce ( m\nta9 glaci]s ab\t ,sn[don 7,*ap4 ,,xxvi74 ,m mature /ages ( ! same processes are to be f\nd 9 ! ,scotti% ,highl&s & ! ,inn] ,hebrides1 b especially ^u ! ,isl& ( ,skye 7,fig4 #dib74 ,a v valuable aid to excursions 9 ?is di/rict is ,baddeley's ,scotl& 7"p ,i1 ,dulau1 ,london7 & ,sir ,ar*ibald ,geikie's ,explanatory ,notes to accompany ,b>?olomew's ,geological ,map ( ,scotl& 7map & notes 9 cov]1 ,ed9burgh1 #ahib1 pp4 #bc74 ,illu/ration3 ,,fig4 #dib4--,sket* map ( ,we/]n ,scotl& & ! ,inn] ,hebrides to %[ location ( "s po9ts ( special geological int]e/4 ,x is f ,oban1 ! 8,*>+ ,cross ( ! ,highl&s01 t "o %\ld />t out ^u ! summ] /eam]s 9 ord] to rea* bo? ,skye & ,/affa1 ! latt] ) f9e basaltic columns 7#dfc71 & ,f+al's ,cave4 ,9 sail+ to ,skye "o passes ^u ei!r %ore ( ! n>r[ fjords _m relics left 9 ! dissection ( volcanoes 7#aci-adc & ,sir ,a4 ,geikie1 ,anci5t ,volcanoes ( ,great ,brita91 ,vol4 ,,ii72 also rocky isl&s & sk]ries m>k+ subm]g5ce 7#beb71 & ! coa/ t]races :i* regi/] a lat] uplift 7#bej74 ,skye is a complex ( _m intrusive & volcanic rocks ( su* m>k$ly diff]5t colors z to appe> z t9ts 9 ! l&scape4 ,9 ! ,cu*ill9 ,hills ( d>k gre5 rises ! massive gabbro 7#dfb7 cut by cirques into ! jagg$ p9nacles ( horns & comb ridges 7#cgc72 :ile l[] d[n & to ! ea/ are r\nd$ domes ( rhyolite 7#dfc7 abrad$ b5ea? ! glaci]s & ( a delicate salmon t9t4 ,/ill l[] & to ! we/w>d are flat mesas compos$ ( horizontal lay]s ( black basalt "u a ri* c>pet+ ( ! brighte/ v]dure4 ,ea/w>d across ! *annel are se5 ! purpli% walls ( an anci5t s&/one4 ,! jagg$ gabbro core ( ! isl& ?us repres5ts a frett$ upl& 7#cgb7 & is n[ ! tra9+ gr\nd ( ! ,alp9i/ 7,abraham1 ,rock ,climb+ 9 ,skye1 ,longmans1 ,london1 #aijh71 :ile ne/l$ 9 "o ( ! bottoms ( a ,u-valley is ,lo* ,coruisk1 a typical rock-bas9 lake 7#dab71 its %ores ( h>d rock plan$ & scor$4 ,f ,skye we may g to /udy ! rem>kable ?ru/s 7#de7 on ! nor? %ore ( ,lo* ,m>ee1 a m>k$ l9eam5t1 & "o direct$ at "r angles to t on ! c\rse ( ! ,cal$onian ,canal connect+ ,lo* ,l9ne ) ,lo* ,ness4 ,?is nor!a/ wall ( ,lo* ,m>ee is a /rik+ly rectil9e> fault repres5t$ by an esc>pm5t1 up :i* we climb to f9d at ! top ! cru%$ & flut$ ?ru/ planes ( movem5t dipp+ s\!a/w>d at a flat angle4 ,"h also are beautiful rock-bas9 lakes1 ly+ 9 holl[s mold$ b5ea? ! cont95tal glaci]4 ,on our way f ,skye we h pass$ up ,lo* ,c>ron1 a sea lo* or fjord 7#beb71 & along ! /ra? at its head kn[n z ,/ra?c>ron 7#dbh74 ,return+ n[ to ,oban1 x is b a %ort trip by /eam] up ,lo* ,l9ne to ,=t ,william along ! /rik+ l9eam5t 7#bbf7 :i* cont9ues to ,lo* ,ness & beyond 7,fig4 #dib71 & !nce by rail to ,gl5 ,roy & ! neighbor+ gl5s ( ,lo*ab] 7#cbb-cbe74 ,f ,p>is z a />t+ po9t1 we may visit 9 a mo/ picturesque region ! beautifully pres]v$ crat]s ( ext9ct volcanoes 9 ! ,auv]gne ( ,c5tral ,france 7#aje1 #abd1 #ade71 :i* di/rict is ent]$ f ,cl]mont-,f]r&4 ,"h are f\nd ! *>act]i/ic puys1 /eep lava domes ( visc\s lava 7#aje71 :i* figur$ l>gely 9 ! e>ly controv]sies ( geologi/s conc]n+ ! orig9 ( rocks4 ,illu/ration3 ,,fig4 #dic4--,outl9e map ( a geological pilgrimage across ! cont95t ( ,europe4 ,! re/ ( our pilgrimage w be s plann$ z to ent] ! noble riv] ,rh9e at its m\? 7,fig4 #dic71 asc5d its c\rse to its bir?place 9 ! sn[s ( ,switz]l&1 & aft] fur!r exploration ( ! features ( ?is frett$ upl&1 trav]se nor!rn & c5tral ,italy s z to make our dep>ture = ,am]ica by ! s\!rn r\te4 ,ent]+ !n ^u ?is c\rse 9 ! ,l[ ,c\ntries1 we h fir/ ! opportunity ( obs]v+ ! *>act]i/ics ( a great delta ) natural levees artificially /r5g!n$ z dikes 7#afe-afh74 ,"h also are f\nd dunes ( bea* mat]ial :i* has be5 rais$ by ! w9d into a great ramp>t ne> ! %ore 7#bji-baa74 ,su* a wall ( dune s& is well display$ at ! ba?+ resort at ,s*ev5+5 ne> ! ,hague 7#dba74 ,! flood pla9 ( ! ,rh9e 7#afb-afe7 may be /udi$ 9 a j\rney up ! riv] to ! univ]sity t[n ( ,bonn1 f :5ce a day's excursion %\ld be devot$ to ! relics ( volcanoes kn[n z ! ,sev5 ,m\nta9s 7,h4 von ,de*51 ,geogno/is*] ,fhr] 9 das ,sieb5gebirge1 ,bonn1 #ahfa74 ,z a prep>ation = ?is trip & o!rs 9 ! volcanic ,eifel high] up ! riv]1 a visit %\ld be made to ! m9]al & rock collections ( ! ,poppelsdorf] ,s*loss at ! ,univ]sity4 ,9 ! volcanic ,eifel are f\nd "s ( ! mo/ int]e/+ ( crat] lakes 7#dje71 ! l>ge/ be+ ,lake ,laa* ) its some:at peculi> volcanic ejectam5ta & its picturesque abbey 7see von ,de*51 ,geogno/is*] ,fhr] zu d] ,vulkanreihe d] ,vord]-,eifel1 etc41 ,bonn1 #ahhf4 ,consult also ,lane1 ,a ,geological ,t\ri/ 9 ,europe1 l4c474 ,cont9u+ our c\rse up ! riv] f ,bonn1 we soon ent] ! gorge ( ! ,rh9e cut 9 an uplift$ p5epla9 7#afi1 #aga1 #agd74 ,f ,cobl5z1 :]e ! ,moselle ent]s ! ,rh9e1 a side trip may be made up ?is tribut>y riv] pa/ ,zell ) its entr5*$ me&]s 7#agc7 to ! anci5t ,roman city ( ,treves4 ,above ,b+5 on ! ,rh9e we leave beh9d u ! n>r[ gorge & rapid curr5t ( ! riv] & cont9ue ov] ! broad floor at ! bottom ( a rift valley 7#djc71 ly+ betwe5 ! =e/ ( ,od9 & ! ,black ,=e/ on ! ea/ & ! 8,blue ,alsatian ,m\nta9s0 f> away to ! we/4 ,at ! m>g9s ( ?is pla9 are b$s ( loess ) _! *>act]i/ic jo9t /ructures & inclusions 7#bjg71 & 9 ! high] hills on ei!r h& a weal? ( intrusive igne\s rocks4 ,at ! entrance ( ! ,neck> ,riv] to ?is broad pla9 is ne/l$ ! picturesque ca/le & univ]sity t[n ( ,heidelb]g1 a conv5i5t c5t] = excursions 7,julius ,ruska1 ,geologis*e ,/reifzge 9 ,heidelb]gs ,umgebung1 etc41 ,ngele1 ,leipzig1 #aijh1 pp4 #bjh1 map74 ,at ,/rassburg 7,s*w>zwald/rasse #ab7 is locat$ ! ,g]man ,*ief ,/ation = ,e>?quake ,/udy1 ) a p>ticul>ly l>ge set ( mod]n seismographs4 ,9 ! univ]sity cab9et is also "o ( ! l>ge/ & mo/ repres5tative m9]al collections 9 ,europe4 ,= excursions 9 ! neighborhood consult ,b5ecke1 ,sammlung ,geogno/is*e ,fhr]1 ,vol4 #e1 ,elsass1 #aijj4 ,f ,/rassburg we may g by ! ,black ,=e/ ,railway to ! ,hegau ) its volcanic plugs 7#adj71 ea* surm\nt$ by a picturesque ca/le4 ,we ent] next ! broadly ext5d$ pi$mont apron site1 above :i* ,lake ,con/ance /ill rema9s z a bord] lake 7#cii74 ,outwa% aprons 7#cad71 mora9es 7#caa71 & druml9s 7#cag7 are ea* 9 turn enc\nt]$4 ,/ill cont9u+ our c\rse up ! ,rh9e f ,breg5z1 we ent] ! frett$ upl& 7#cgb7 ( ! ,alps1 m\nta9s compos$ ( great folds & ?ru/s ab\t a core ( intrusive rock 7,ro?pletz1 ,sammlung ,geologis*e ,fhr]1 ,vol4 #aj1 #aijb1 ,?ru/s 9 ! ,alps betwe5 ,lake ,con/ance & ! ,engad9e74 ,"s f\rte5 miles above ,*ur we pass ! t]race produc$ by successive l&slides 7#dad71 kn[n f> & wide z ! ,flims] ,b]g/rz4 ,! fur!r ass5t ( ! cascade /airway ( ?is glaci]-c>v$ valley br+s u to ! ,furka ,pass1 f :i* po9t magnific5t views ( ! frett$ upl& are obta9$4 ,at ! ,knzli1 a mile f ! hotel1 "o may view ! nv ( ! ,rhone ,glaci]1 :i* may also be easily visit$4 ,we h n[ foll[$ a great riv] f its m\? 9 ! s&s ( ,holl& to its s\rce 9 ! sn[s ( ! high] ,alps4 ,pass+ ov] ! divide & desc5d+ to ,glets*1 we may obs]ve ! l[] end1 or foot1 ( ! ,rhone glaci] & ! crevasses & sracs 7#cia7 on ! /eep desc5t ( ?is radiat+ glaci] 7#chc1 #chf74 ,! response :i* glaci]s make to climatic *anges is "h well illu/rat$ by ! recession ( ! glaci] front f ne> ! hotel 7its position 9 ! '#ejs ( ! n9ete5? c5tury7 to its pres5t position ab\t a mile f>!r up ! valley4 ,! *>act]i/ics ( a glaciat$ m\nta9 valley may be fur!r illu/rat$ by climb+ to ! ,grimsel ,pass1 :i* is scrat*$ & /riat$ 7#cgg1 #che71 & !n desc5d+ ! valley ( ! ,a> to ,meyr+5 7#cgg74 ,ne> ! ,grimsel ,hospice are ! *>act]i/ic rock bas9 lakes 7#dab71 & ^u ! ,a> ,glaci] to our left 7 c>ri$ out ! epo*-mak+ rese>*es ( ,l\is ,agassiz1 ! f\nd] ( ! glacial !ory = expla9+ ! drift4 ,we enc\nt] "s ?irte5 rock b>s 7#cgg74 ,j be=e rea*+ ,meyr+5 we pass ! la/ ( ^!1 ! ,gorge ( ! ,a>1 cut by ! /ream ?r\gh lime/one4 ,int]lak5 7#dai7 may be made ! c5t] = additional excursions up ! ,laut]brunn5 ,valley1 ) its prom95t albs 7#cgf7 & its ribbon fall ( ! ,/aubba* 7#cgh74 ,by ! ,jungfrau ,m\nta9 railway we may n[ asc5d p>tly 9 tunnels ( ! rock to ! ,ewigeisme]1 & look d[n ^u ! nv & b]gs*runds ( ! ,great ,alets* ,glaci] 7#cgj1 see ,baltz]1 ,sammlung ,geologis*e ,fhr]1 ,vol4 #aj1 ,b]nese ,ob]l&1 #aijf74 ,return+ to ,int]lak5 by way ( ,gr9delwald1 "o may /udy ! foot ( a radiat+ glaci]1 ! ,unt]gr9delwald glaci]1 ) its tunnel & its milky & braid$ /ream4 ,cross+ n[ ! ,alp9e =el& to ,vill5euve at ! upp] end ( ,lake ,g5eva & ^u a well-develop$ /ra? 7#dbf1 #dbh71 we may look out ^u ! turbid wat]s ext5d+ f> f ! %ore ( ! lake4 ,j\rney+ to ,g5eva by /eam] we note ! gradual cle>+ ( ! wat] until at ! outlet ( ! lake x is z cle> z cry/al4 ,a walk+ trip f ,g5eva takes u to ! ,bois de la ,btie1 :]e ! ,arve ) turbid wat]s meets ?is cle> /ream 7#dbg74 ,! railroad to ,*amonix asc5ds ano!r cascade /airway 7#cgf71 af=ds views ( complexly fold$ s$im5t>y rocks 7#dc71 & at ,*amonix itself ! m] de glace supplies opportunities = ! /udy ( mora9es 7#chf1 #cic7 & glacial movem5t 7#cij-cib74 ,to exp]i5c$ ,alp9i/s ! summit ( ,m\nt ,blanc (f]s a rem>kably ext5d$ outlook ov] ! frett$ upl& ( ! ,alps 7pl4 #ah ,a74 ,f ! /ation ( ,le,fayet bel[ ,*amonix1 "o may asc5d to ! ,ds]t de la ,plat1 :]e are ,s*ratt5 9 lime/one due to solution 7#ahh74 ,cross+ by "o ( ! passes to ! valley ( ! ,rhone at ,m>tigny we may rea* ,z]matt1 to-day ! climb+ c5t] ( ! ,alps4 ,f ! subord9ate cirques surr\nd+ ?is village desc5d ! ,gorn]1 ,f9del51 ,/4 ,!odul1 & o!r compon5ts ( ?is radiat+ glaci]4 ,a black too? ( rock1 ! ,matt]horn1 t[]s above ! o!r peaks & %[s to greate/ advantage ?is feature ( glacial sculpture 7#cgd71 :ile ! ,gorge ( ! ,gorn] is a sev]$ rock b> l t ( ! ,a> 7#cgg74 ,ei!r on foot or ov] ! m\nta9 railway we may asc5d to ! ,gorn] ,grat1 a subord9ate comb ridge 7#cgc7 :i* af=ds "o ( ! mo/ magnific5t & in/ructive views ( radiat+ glaci]s4 ,f ,brig1 f>!r up ! ,rhone ,valley1 an excursion is made to ! ,eggi%orn ,hotel1 a c5t] = /udy on & ab\t ! ,great ,alets* ,glaci] 7#cbi1 #cga1 #che1 #chh1 #cie1 #daj74 ,! easy asc5t ( ! ,eggi%orn is rew>d$ by a view almo/ directly d[nw>d ^u ! ice-damm$ ,mrjel5 ,lake 7#cbi1 #daa74 ,f ,brig "o may make 8 entry into ,italy1 ei!r ov] ! picturesque ,simplon r\te afoot or by dilig5ce1 or else b5ea? x ?r\gh ! railway tunnel4 ,by an alt]nation ( %ort /eamboat & rail trips ! j\rney is cont9u$ 9 a direction transv]se to ! long] axes ( ! bord] lakes ,maggiore1 ,lugano1 & ,como1 & lat] s\?w>d to ,milan4 ,9 leav+ ! village ( ,como we pass ov] heavy mora9ic deposits on ! apron bord]s ( ! exp&$-foot glaci] 7#chc1 #che7 :i* once occupi$ ! valley above4 ,on ! j\rney f ,milan to ,v5ice1 ov] ! f]tile pla9s ( ,lomb>dy1 ! simil> accumulations ab\t ,lake ,g>da 7#dad7 are fir/ enc\nt]$ at ! little /ation ( ,lonato & left beh9d at ,somma ,campagna 7,tornqui/1 ,sammlung ,geologis*e ,fhr]1 ,vol4 #i1 ,nor!rn ,italy1 #aijb74 ,! city ( ,v5ice is built ^u pile f\ndations 9 ! lagoon beh9d ! b>ri] bea* kn[n z ! ,lido 7#bdb1 #dbh-dbi74 ,f "h we may rea* ! ,k>/ c\ntry by way ( ,trie/e1 "s ( ! m int]e/+ & typical features be+ f\nd ne> ,divaa 7#ahg-ahi1 #dbb1 pl4 #f ,a74 ,9 a diff]5t direction f ,v5ice by way ( ,belluno we ent] ! ,dolomites ) _! patt]n$ relief & battlem5t$ t[]s 7#bbh1 #dde74 ,additional c5t]s = geological excursions on ! r\te to our po9t ( dep>ture f ,italy are ,rome & ,naples4 ,at ! ,italian capitol & 9 its neighborhood we may /udy ! volcanic ,campagna ) its b$s ( tuff 7#aje7 & its crat] lakes 7#dje4 ,see ,sir ,a4 ,geikie1 ,! ,roman ,campagna1 ,l&scape 9 ,hi/ory & o!r ,essays1 ,macmillan1 #aije1 pp4 #cjh-ceb2 also ,deecke1 ,sammlung ,geologis*e ,fhr]1 ,vol4 #h1 ,campagna1 #aija74 ,f ,rome x is an easy j\rney to ! cat>act ( ,tivoli ) its deposits ( trav]t9e 7#ahd74 ,9 ! opposite direction f ,rome across ! ,campagna rise ! ,alban ,hills1 ru9s ( a composite cone ) sev]al crat] lakes on ! sites ( =m] v5ts4 ,on ! summit ( ! encircl+ crat] rim1 l ! ,monte ,somma ( ! ,vesuvian ,m\nta9 n[ a cresc5t only1 is locat$ ! *ief ,italian /ation = e>?quake /udy4 ,f ,naples we may rea* 9 %ort excursions & /udy ) "s c>e /ill active volcanic m\nta9s4 ,to ! ea/ is ,m\nt ,vesuvius 7#id1 #ig1 #abb1 #abd1 #abg-acg71 :i* 0 9 gr& eruption 9 ,april1 #aijf4 ,we/w>d f ,naples are ! ,campi ,phlegraeii1 or burn+ fields1 ) _m crat]s4 ,( ^! ,a/roni (f]s a f9e example ( a l>ge-crat]$ c9d] cone 7#aje74 ,9 ! same vic9ity are ,monte ,nuovo 7#if7 & ! ,solfat>a 7#ig71 ! latt] a type ( volcano :i* no long] erupts lava1 b 9 its place emits c>bon dioxide & o!r gase\s emanations 7,grotto del ,cane74 ,! />t+ po9t = excursions 9 ! ,phlegran fields is ,pozzuoli ) its ,temple ( ,jupit] ,s]apis 7#bed-bee71 rea*$ f ,naples by an electric l9e :i* pi]ces ! wall ( an imm5se crat] 7,posilippo7 compos$ ( f9e yell[ volcanic a% kn[n z ,pozzuolan4 ,f ,naples /eam]s make %ort excursions to ,sorr5to ) its deep a% deposits1 & to ,capri ) its blue grotto 7#beg-beh74 ,h]culaneum 7#aci7 & ,pompeii 7#abb71 buri$ dur+ ! eruption ( #gi ,a4,d41 are on ! l9e ( ! ,circum-,vesuvian ,railway4 ,/eam%ips to ,new ,york f ,naples call at ,gibralt>1 ! l&-ti$ isl& p> excell5ce 7#bda74 ,mo/ /eam%ips ( ! s\!rn r\te pass ?r\gh or ne> ! volcanic isl&s ( ! ,azores1 & c]ta9 boats t\* at ,algi]s1 f :i* a l9e ( railway gives access to ,biskra on ! bord]s ( ! ,des]t ( ,sah>a4 ,?r\gh\t ^! pilgrimages ! travel] %\ld be on ! al]t to note n only ! ag5t responsible = ! features :i* come "u 8 obs]vation1 b1 especially :]e ?is is ! common sculptur+ ag5t ( runn+ wat]1 he %\ld n fail to notice ! /age ( ! erosion cycle :i* is repres5t$ 7,*apt] ,,xiii74 ,,index ,abrasion1 b5ea? glaci]s1 #bge4 ,abyss9ia1 fissure eruptions 91 #aja4 ,accordance1 ( tribut>y valleys1 #afb4 ,adiabatic refrig]ation1 9 relation to glaci]s1 #bfb4 ,adolesc5ce1 9 cycle ( erosion1 #afi4 ,advanc+ hemicycle ( glaciation1 #bfc-bff4 ,advective zone1 ( atmosph]e1 #bgj4 ,aft]%ocks1 ( e>?quakes1 #hc4 ,agassiz1 glacial lake1 #cbe-cbh4 ,agassiz1 ,l\is1 cit$1 #cci1 #djj4 ,age1 ( /rata1 #ch1 #eb4 ,aggradation1 #afb4 ,aktian deposits1 #cf4 ,alaskan coa/1 map (1 #gi4 ,albs1 #cgf4 ,ald51 ,w4 ,c41 cit$1 #caf1 #cah1 #cai4 ,alg1 gr[? (1 9 hot spr+s1 #aid4 8,alkali0 9 des]ts1 #bja4 ,alluvial b5*1 #bad4 ,alluvial cone1 #bac4 ,alluvial-dam lakes1 #dbc4 ,alluvial fan1 #bac4 ,alp9e glaci]s1 #chc1 #chf4 ,alt]ations ( m9]als1 #bg4 ,altitude1 ( diff]5t p>ts ( li?osph]e1 #ah4 ,am]ican ,falls1 future ext9ction (1 #ceg4 ,amphiboles1 #dei4 ,amphi!at]s1 =m$ on drift sites1 #cfi4 ,amunds51 ,r41 cit$1 #bc4 ,analysis1 ( folds1 #ed4 ,&]son1 ,tempe/1 cit$1 #adf1 #adg4 ,&]sson1 ,j4 ,g41 cit$1 #aeg1 #bie4 ,&esite1 #dfc4 ,angul> uncon=mity1 #ec4 ,ant>ctica1 #aed1 #bha4 ,ant>ctic protub]ance1 #ag4 ,ant>ctic %elf ice1 #bhi1 #bij4 ,anticl9al folds1 #db4 ,anticl9es1 #db2 t5sion 91 #de4 ,anticyclone1 glacial1 #bhd4 ,ants1 factor 9 rock decomposition1 #aef4 ,apron1 alluvial1 #bac4 ,aprons1 outwa%1 #bhj1 #bha4 ,arb5z1 ,p41 cit$1 #aie4 ,ar*es1 ( fold$ /rata1 #db2 sea1 #bcc1 #bcd4 ,ar*itecture1 ( fractur$ e>? sup]/ructure1 #ee4 ,arctic depression1 #ag4 ,areal geological map1 #fb4 ,artes1 #cgc4 ,arldt1 ,!odore1 cit$1 #aa1 #ai1 #dch4 ,arnold1 ,ralph1 cit$1 #aeg4 ,arrangem5t ( oceans & cont95ts1 #aj4 ,artesian wells1 #aij1 #aia1 #aif4 ,a%1 volcanic1 #abb4 ,askja1 eruption (1 9 #ahge1 #aja4 ,assmann1 ,r41 cit$1 #bid4 ,a/ronomical vs4 geodetic obs]vations1 #ab4 ,atlantis1 ,nor?1 #af4 ,atmosph]e1 compressibility (1 #h4 ,attack1 ( ! wea!r1 #adi4 ,atwood1 ,w4 ,w41 cit$1 #g1 #afj1 #bih1 #cjj1 #cac1 #cgb4 ,axial plane1 ( folds1 #db4 ,axis1 ( folds1 #db4 ,azurite1 #dec4 ,bact]ia1 "p tak5 9 wea!r+1 #aef4 8,bad ,l&s01 control ( relief 91 #bbc1 #bbd4 8,bad ,l&0 topography1 #bad4 ,bajir1 #baf4 ,balance1 betwe5 degradation & aggradation1 #afa4 ,b&ai-san1 dissection (1 #ada4 ,b>*ans1 #baa4 ,b>rancoes1 #aci4 ,b>rell1 ,j41 cit$1 #bba1 #ddg4 ,b>ri] bea*es1 #bdj2 sections (1 #bdb2 uplift$1 #bdi1 #bej4 ,b>ri] lakes1 #dbj4 ,b>ri]s1 #bdj2 m\nta91 9 relation to glaci]s1 #bfb4 ,b>s1 #bdj4 ,basal conglom]ate1 #cg1 #ec4 ,basalt1 #dfc2 fault$ blocks (1 #eh2 ( ,hawaii1 #aje4 ,base level1 #aei4 ,bas9-range lakes1 #djb1 #djc4 ,bas9 ,range /ructure1 #ddj4 ,bas9s1 flat bottom$1 sep>at+ dunes1 #baf2 ( exudation1 #bgb2 ( s$im5tation1 e>li]1 #ch4 ,ba/91 ,e4 ,s41 cit$1 #baj4 ,ba?olites1 #adc4 8,ba? tubs01 #cie4 ,bea* pebbles1 #bci4 ,bea* s&1 #bjf1 #bch4 ,bea*es1 rema9+ f ice-dam lakes1 #daj2 %+le1 #bci2 /orm1 #bdj2 uplift$1 8fea!r+ out0 (1 #cdd4 ,b$d$ /ructure ( rocks1 #ca4 ,be$e1 ,j4 ,w41 cit$1 #aie4 8,bee-hive0 m\nta9s1 #chj1 #cha4 ,belgica exp$ition1 #bhi4 ,belt ( sea :i* divides l& masses1 #aa4 ,b]ghaus1 ,h41 cit$1 #dbd4 ,b]gs*rund1 #cgj4 ,b]son1 ,a41 cit$1 #bid4 ,b]?aut1 ,g5]al1 cit$1 #g4 8,bird-foot0 delta1 #afg4 8,biscuit cutt+0 effect ( glacial sculpture1 #cgb4 ,blackweld]1 ,e41 cit$1 #cah4 ,block m\nta9s1 #ddf4 ,blocks1 orographic1 #eh4 ,boc*i1 #abe4 ,bog1 float+1 #dbi4 ,bogs1 ( peat1 #dbi1 #dcj4 ,bonney1 ,t4 ,g41 cit$1 #adf4 ,borax deposits1 9 des]ts1 #bja4 ,bord] dra9age1 ab\t glaci]s1 #caf1 #cbj1 #cba4 ,bord] lakes1 #cii1 #dad4 ,bosses1 #adc4 8,bottoms01 f entr5*$ me&]s1 #agc4 8,b[ld] clay01 #caj4 8,b[ld] pavem5t01 #bcg4 ,b[ld]s1 facet$1 #caj2 glacial1 #bih2 8sol$01 #bgf1 #caj2 ?r[n up dur+ e>?quakes1 #fi4 ,b[ld] tra9s1 #cjf4 ,b[man1 ,isaiah1 cit$1 #agi4 ,box caons1 #bad4 ,braid$ /reams1 #bhj4 ,brann]1 ,j4 ,c41 cit$1 #f1 #ia4 8,bread-cru/0 lava projectiles1 #aai4 ,break]s1 #bcb4 ,breccia1 fault1 #fj4 ,bridges1 nature ( damage to1 dur+ e>?quakes1 #ge1 #gf4 ,brigham1 ,a4 ,p41 cit$1 #dbd4 ,brgg]1 ,w4 ,c41 cit$1 #ff4 ,bruce1 ,w4 ,s41 cit$1 #bij1 #chb1 #cii1 #dad4 ,bryant1 ,h4 ,g41 cit$1 #bhi4 ,buckley1 ,e4 ,r41 cit$1 #dcc1 #dcd4 ,built t]races1 #bce4 ,buns51 cit$1 #aib4 ,burns1 ,g4 ,p41 cit$1 #dcd4 ,burton1 ,w4 ,k41 cit$1 #ib4 ,buttes1 #baf4 ,bysmalite1 #ddb1 #ddg4 ,calc>e\s ooze1 #cf4 ,calc>e\s s9t]1 #ahd4 ,calc>e\s tufa1 #dfd4 ,calcite1 #dee4 ,cald]a1 #dje1 ( composite volcanic cones1 #abf4 ,camigu9 volcano1 bir? (1 #if1 #ig4 ,campbell1 ,m4 ,r41 cit$1 #agh4 ,caons1 #afj2 box1 #bad4 ,capri1 blue grotto (1 #beg1 #beh4 ,capture1 riv]1 #age1 #agf1 #agi4 ,c>bonization1 #aea4 ,cascade ,m\nta9s1 fissure eruptions (1 #ajb4 ,cascade /airway1 #cgf4 ,caspian ,depression1 #ad4 ,caulifl[] cl\d1 #acj4 ,cav]ns1 gall]ies direct$ by jo9ts1 #ahb2 ( lime/one1 #ahb1 #aie2 refuge ( pr$atory animals1 #ahe4 ,caves1 sea1 #bcd4 ,cellul> /ructure1 ( lava domes1 #aab4 ,c5t]s ( disp]sion1 ( ,nor? ,am]ican ,plei/oc5e glaci]s1 #bih4 ,c5trosph]e1 #h4 ,c]ussite1 #dee4 ,*aix1 ,a41 cit$1 #aie4 ,*aix1 ,e41 cit$1 #aie4 ,*alcopyrite1 #dec4 ,*all5g] exp$ition1 #ch1 #if1 #ig1 #bic4 ,*amb]l91 ,t4 ,c41 cit$1 #bi1 #aef1 #aia1 #aif1 #bje1 #bba1 #bbb1 #bic1 #bie1 #cah1 #cai1 #ccg1 #cci4 ,"* pr(iles1 coa/1 due to uplift or depression1 #bei2 composite1 #bbi2 directly due to volcanic ag5cies1 #ade1 #adf2 f /ream erosion 9 humid climates1 #agg2 ( arid l&s1 #bbj2 ( %ore features1 #bdc2 ref]able to cont95tal glaci]s1 #cah2 ref]able to m\nta9 glaci]s1 #cgi4 8,*eck]bo>d topography01 #bbf4 ,*emical s$im5ts1 #cd4 ,*icago outlet1 #cca4 ,*imneys1 9 8driftless area01 #cjj4 ,*imneys1 %ore feature1 #bcd4 ,*9a1 loess (1 #bjg4 ,*lorite1 #deh4 ,*lorite s*i/1 #dfe4 ,cicatrice1 f dissection ( volcanoes1 #adb4 ,c9d] cones1 #aje2 corrugations ^u1 #ach2 diamet] ( crat] 9 relation to viol5ce ( explosions1 #abc2 gr&] eruptions (1 #aag2 pr(iles (1 #abc2 second>y1 #aaa4 ,c9d] eruptions1 artificially simulat$1 #abb4 ,cirques1 #cga2 life hi/ory (1 #cga2 subord9ate1 #cga4 ,cities1 de/ruction (1 by drift+ s&1 #bah4 ,cla/ic rocks1 #cj4 ,clay slate1 #dff4 ,cleavage1 m9]al1 #bg1 #dej2 rock1 #dd4 ,clefts1 volcanic1 9 ,icel&1 #ii4 ,cliffs1 not*$1 #bcc4 ,climatic conditions1 9 relation to m\nta9 sculpture1 #ddc4 ,cl9omet]1 #dh4 ,cl\dbur/s1 9 des]ts1 #bja1 #bab4 ,cl\d zones1 #bfh1 #bfi1 #bid4 ,coals1 #dff4 ,coa/1 ,dalmatian1 grottoes (1 #beh4 ,coa/1 elevation (1 dur+ e>?quakes1 #hj2 subm]g5ces (1 dur+ e>?quakes1 #hj4 ,coa/al pla9s1 #bdf2 belt$1 #bdg4 ,coa/ l9es1 ev51 #bdf2 indicative ( uplift or subm]g5ce1 #bde1 #bdf2 ragg$1 #bdf4 ,coa/ records1 #bde4 ,coa/s1 ,atlantic & ,pacific contra/$1 #dch2 embay$1 #bea4 ,coa/ t]races1 #hj1 #bej1 #bda2 uplift1 effect (1 on s$im5ts1 #ch4 ,coats ,l&1 %elf ice (1 #bij4 ,cobalt1 9 meteorites1 #bc4 ,cobb1 ,colli]1 cit$1 #agi4 ,coigns1 ( e>?'s tetrah$ral figure1 #ae4 ,coleman1 ,a4 ,p41 cit$1 #cah4 ,colk lakes1 #djh1 #dji4 ,colks1 scape1 #bgg4 ,collet1 ,l4 ,w41 cit$1 #ci4 ,colorado des]t1 #gd4 ,color1 ( m9]als1 #dej4 ,cols1 #cgd2 orig9 ( 9 cirque int]section1 #cgb4 ,comb ridges1 #cgc4 ,compass1 geologi/'s1 #dg1 #dh4 ,compet5t lay]1 #db2 9 relation to lava res]voirs1 #add4 ,composite cones1 cald]a (1 #abf1 #abg4 ,composite gr\ps ( jo9ts1 #eg4 ,composite volcanic cones1 #aje4 ,composition ( e>?1 #bi4 ,composition ( ! e>?'s core1 #ba4 ,compression ( a di/rict dur+ e>?quakes1 #gf4 ,cones1 alluvial1 #bac2 c9d]1 #aje2 composite volcanic1 #aje4 ,con=mable s]ies1 #ea4 ,conglom]ate1 #cd1 #dfc2 basal1 #cg1 #ec4 ,con/ructional topography1 #cji4 ,con/ruction ( build+s1 9 e>?quake regions1 #hi-ia4 ,cont95tal glaci]1 beh9d ramp>t1 #bha2 9 ,victoria ,l&1 #bhj-bhe2 ( ,ant>ctica1 lit]ature (1 #bie2 ( ,gre5l&1 #bga2 ( ,gre5l&1 melt+ on m>g9 (1 #bgh2 ( ,gre5l&1 lit]ature1 #bie4 ,cont95tal glaci]s1 contra/$ ) m\nta9 glaci]s1 #bff-bfh2 def9$1 #bff-bfg2 ( 8ice age01 #big2 ( ice age1 cross section (1 #cjb2 n\ri%m5t (1 #bhc1 #bhf1 #bie2 pr(iles (1 #bfg4 ,cont95tal plat=m1 #ai4 ,cont95tal %elves1 #ah1 #ai2 orig91 #bcb4 ,cont95ts1 arrangem5t (1 #aj2 developm5t (1 #ad2 increase 9 area (1 ?r\gh wave action1 #bda2 pa/ hi/ory (1 #ad4 ,contortions ( ! /rata1 #dj4 ,cont\rs1 ( topographic maps1 #fb4 ,contraction ( e>?'s surface1 dur+ e>?quakes1 #gd4 ,contr>y movem5ts ^u coa/s1 #bed1 #beg4 ,convective zone1 ( atmosph]e1 #bgj4 ,conway1 ,w4 ,m41 cit$1 #bid4 ,cop]nicus1 cit$1 #aj4 ,copp] glance1 #dee4 ,coqu9a1 #ce4 ,corni%1 ,vaughan1 cit$1 #baa1 #bbb1 #bdd4 ,corrasion1 #afb4 ,corrosion1 ( rocks1 #aef4 ,c\le lakes1 #djf4 ,coves1 #bcc1 #bcd4 ,cracks1 e>?quake1 #gd4 ,crat]1 evolution ( =m (1 #abh4 ,crat] lakes1 #dje1 #djf4 ,crat]lets1 #hd2 sections (1 #he4 ,crat]s1 me*anics ( explosions 91 #aae4 ,crat]1 volcanic1 #ie4 ,cr$n]1 ,g4 ,r41 cit$1 #agi4 ,cresc5tic levee lakes1 #daf1 #dag4 ,cre/l9e1 ( an anticl9e1 #db4 ,crevasse1 m>g9al1 on m\nta9 glaci]s1 #cgj4 ,crevasses1 9 connection ) riv] cut-(fs1 #afd2 on glaci]s1 #cia4 ,cross1 ,:itman1 cit$1 #baf1 #dda1 #ddg4 ,cross-b$d$ /ructure1 #cg4 8,cry/al cell>s01 #bg4 ,cry/al =m1 ( m9]als1 #ddi4 ,cry/als1 behavior "u special treatm5t1 #bd1 #be2 ess5tial nature (1 #bc2 =ms (1 #ded1 #deg2 individuality (1 #bd2 mutilat$1 lat] gr[? (1 #bf2 symmetry ( =m (1 #bc4 ,cru/al %ort5+1 #db4 ,cue/as1 #bdf1 #bdg2 s\? ( ,lake ,ont>io1 #cfa1 #cfb4 ,cut & built t]race1 on /eep %ore ( loose mat]ials1 #bcg4 ,cut-(fs1 ( me&]s1 #afd4 ,cut rock t]races1 #bce4 ,cuvi]1 cit$1 #aii4 ,cviji1 ,j41 cit$1 #aie4 ,cycle ( glaciation1 #bfc1 #bid4 ,cycles1 ( glaciation1 ,plei/oc5e1 #big2 ( /ream me&]s1 #afc4 ,dana1 ,j4 ,d41 cit$1 #f1 #ajd1 #ajf1 #aji1 #aaa1 #adf1 #adg4 ,dana1 ,e4 ,s41 cit$1 #bi4 ,daly1 ,r4 ,a41 cit$1 #ddg4 ,dante1 cit$1 #i4 ,d>ton1 ,n4 ,h41 cit$1 #agi4 ,d>w91 ,*>les1 cit$1 #aii1 #cbb1 #cbc1 #cci4 ,daubre1 ,a41 cit$1 #ed4 ,david1 ,t4 ,w4 ,e41 cit$1 #bc4 ,davis1 ,c4 ,a41 cit$1 #dcd4 ,davis1 ,w4 ,m41 cit$1 #g1 #agh1 #agi1 #bba1 #bdg1 #bgf1 #cag-cai1 #cgh1 #chb4 ,deceptive uncon=mity1 #ec4 ,decomposition1 #adi1 #aef2 me*anical results (1 #aej4 ,dbris cones1 #cie4 ,deep sea deposits1 #cf1 #ch4 ,deflation1 #bjd4 ,de=e/ation1 9 relation to agriculture1 #aef2 ( ,k>/ region1 #ahh2 relation to erosion1 #aeg4 ,deg5]ation1 #adi4 ,de ,ge]1 ,g41 cit$1 #cea1 #cff1 #daj4 ,degradation1 #afa1 #afb4 ,dekkan1 fissure eruptions (1 #aja4 ,delebecque1 ,a41 cit$1 #dbd4 ,de ,lor5zo1 cit$1 #abe1 #acb4 ,delta1 8,bird-foot01 #afg2 bottom-set b$s1 #afg2 dry1 #bac2 ( ,mississippi ,riv]1 rate ( gr[? (1 #afh4 ,delta deposits1 mann] ( gr[? (1 #afg4 ,delta lakes1 #dai1 #dbj4 ,delta region1 ( a riv]1 #ce4 ,deltas1 abnormal1 bel[ outlets ( lakes1 #dca2 9 relation to agriculture1 #aff2 9 relation to population1 #aff2 lake1 #dbh2 ( riv]s1 #afe1 #aff1 #agi2 sections (1 #afh4 ,d5dritic glaci]s1 #chc1 #che1 #chf4 ,d5i/on1 cit$1 #aba4 ,deposition1 9 zones ab\t des]t1 #baf1 #bag4 ,deposits1 aktian1 #cf2 *emical1 #cd2 cont95tal1 #cg2 deep sea1 #cf1 #ch2 delta1 mann] ( gr[? (1 #afg2 fluviatile1 #ce2 fluvio-glacial1 #ca1 #caj2 9 valley vacat$ by glaci]1 #cih2 glacial1 #ca2 lacu/r9e1 #ce1 #bag2 littoral1 #cf2 m>9e1 #ce2 me*anical1 #cd2 organic1 #cd2 salt1 #bag2 %oal wat]1 #bf2 s9t]1 #ahd2 t]rig5\s1 #cf4 ,d]angem5t ( wat] fl[1 dur+ e>?quakes1 #hc1 #hd4 ,d]wies1 ,v4 de1 cit$1 #ddg4 ,desc5t ( gr\nd wat]1 #ahj4 ,des]t1 due to de=e/ation1 #aef2 erosion 91 #bad1 #bbb2 law (1 #aig4 ,des]t lakes1 #dbc4 ,des]t l&scapes1 features 91 #bji4 ,des]t ra9s1 #bab4 ,des]t rocks1 r$ color (1 #bbb4 ,des]t v>ni%1 #bja1 #bbb4 ,des]ts1 =m] %ore l9es 91 #aih2 self-regi/]+ gauge ( pa/ climates1 #aih4 ,de/ructional topography1 #cji4 ,detection ( plung+ folds1 #di1 #ej4 ,detonations1 dur+ ,vulcanian eruptions1 #aca4 ,device1 to simulate build+ ( c9d] cones1 #abb4 ,diabase1 #dfb4 ,diagram1 to illu/rate =mation ( lava res]voirs1 #adc4 ,diagrams = comp>ison ( fold types1 #db2 to %[ ! effect ( sph]oidal wea!r+1 #aej4 ,diamonds1 9 ! drift1 #cjg4 ,diffission1 #bjd4 ,dikes1 holl[1 #adj2 9 ,*9a1 #afg2 9 ,holl&1 #aff2 f volcanic dissection1 #adj4 ,dill]1 ,j4 ,s41 cit$1 #ci1 #dbe4 8,diluvium01 #cje4 ,dimples1 on m>g9 ( cont95tal glaci]s1 #bgb4 ,dip1 #df4 ,dirt cones1 #cif4 ,dis9tegration1 #aef2 ( rocks 9 des]ts1 #bjb2 ?r\gh root expansion1 #aed2 ?r\gh tree gr[?1 #aed1 #aee4 ,dislocations1 m>g9al1 ab\t des]ts1 #bab4 ,disp]sion ( ! drift1 #cjd-cji1 #cai4 ,displacem5t1 total1 on faults1 #ei4 ,dissection ( volcanoes1 #aci4 ,di/ribut>ies1 on alluvial fans1 #bac1 #bbj4 ,divides1 #agj2 migration (1 #age4 ,dol9es1 ( ,k>/ region1 #ahg1 #dbb4 ,dolomite1 #dfe4 ,dolomites1 #bjc1 #bbh1 #dde4 ,dom$ m\nta9s ( uplift1 #dda4 ,dome /ructure1 ( granite masses1 #aeb1 #aeg4 ,domes1 lava1 #aje4 ,dovetail+1 ( sea & l&1 #aa1 #ag4 ,dra9age1 *anges (1 due to glaciation1 #ccf-cch2 haphaz>d1 ( glaciat$ area1 #cja2 int]f]5ce ( glaci]s )1 #cbj2 ( glaci]s1 #cig2 rev]sals (1 due to glaciation1 #ccg1 #cch2 trellis1 #age4 ,dra9age l9es1 control (1 by fractures1 #bbd4 ,dra9age networks1 controll$ by fractures1 #bbe1 #bbf2 repeat+ patt]n 91 #bbe4 ,drake1 ,sir ,francis1 circumnavigation ( ! globe1 #aj4 ,dreikant51 #bje4 ,driblet cones1 #ajd1 #abe2 ( ,kilauea1 #ajg4 8,drift01 #cje4 ,drift1 assort$1 #cji2 disp]sion (1 #cjd-cji2 englacial1 #bgg1 #bgh2 unassort$1 #cji4 8,driftless area01 #cjj1 #cac1 #cah4 ,driftless area1 map (1 #bih4 ,drift sites1 #cfh1 #cfi4 ,dr[n$ riv]s1 #bea4 ,druml9s1 #caa1 #caf1 #cag1 #cii4 ,dry deltas1 #bac4 ,drygalski1 ,e4 von1 cit$1 #bgc1 #bgi1 #bie1 #bif4 ,dry wea!r+1 9 des]ts1 #bja4 ,dune1 w> ) oasis1 #baf4 ,dune lakes1 #dba4 ,dunes1 #bbb2 =ms (1 #baj1 #baa2 9 relation to ob/ructions1 #bji1 #baj2 /opp$ by vegetation1 #baa2 w&]+1 #bji1 #baa4 ,du/1 c>ri$ out ( des]t1 #bjf1 #bbb2 volcanic1 #abb4 ,du/ wells1 #cie4 ,dutton1 ,c4 ,e41 cit$1 #he1 #ib1 #agh1 #bjj1 #bbb1 #ddg4 ,e>li] figures ( ! e>?1 #ad4 ,e>?1 a magnet1 #bc2 composition (1 #bj2 oblat5ess (1 #aj2 rigidity (1 #bj1 #ba1 #bi2 scale ( its elevations1 #aj1 #aa2 !ories ( orig9 (1 #bj1 #bi2 surface %ell1 *emical con/itution (1 #bc2 surface %ell1 response to load1 #cdj4 ,e>? features1 %ap$ by runn+ wat]1 #afi4 ,e>? figure1 evolution ( ideas conc]n+1 #i4 ,e>?quake cracks1 #gd4 ,e>?quake f\nta9s1 #aij4 ,e>?quake lakes1 #djd4 ,e>?quake1 ( ,alaska1 #ahii1 #gb1 #gg1 #gi1 #hj1 #ha2 ( ,assam1 #ahig1 #gb1 #gg2 ( ,cali=nia1 #aijf1 #gj1 #gb1 #gc1 #gd1 #ij1 #ia2 ( ,casamicciola1 #ahhc1 #hg2 ( ,co/a ,rica1 #aiaj1 #fh2 ( ,india1 #ahai1 #hd2 ( ,jamaica1 #afib1 #hj2 ( ,jamaica1 #aijg1 #hj2 ( ,japan1 #ahia1 #gb1 #ge2 ( l[] ,mississippi ,valley1 #ahaa1 #hc2 ( ,mess9a1 #aijh1 #fh2 ( ,ow5s ,valley1 ,cali=nia1 #ahgb1 #gc1 #gg1 #gh1 #gi2 ( ,s]via1 #aijd1 #hd2 ( ,s\? ,c>ol9a1 #ahhf1 #he4 ,e>?quake %ocks1 heavy ov] loose f\ndations1 #hh4 ,e>?quakes1 aft]%ocks (1 #hc2 associat$ ) gr[+ m\nta9s1 #hf2 *anges 9 e>?'s surface dur+1 #ga2 connect$ ) l9es ( fracture1 #hf2 descriptive reports ^u1 #ib2 due to adju/m5ts betwe5 blocks ( %ell1 #gh1 #gi2 faults & fissures1 #ga2 focus$ at fault int]sections1 #hg2 f\nta9s dur+1 #hc1 #hf2 localiz$ at corn]s ( e>? blocks1 #hg2 manife/ations ( *anges 9 level1 #fh2 nature ( %ocks1 #fg2 ( ,is*ia1 localization (1 #hg2 %[n by coa/ t]races1 #bej2 special l9es ( heavy %ock1 #hf2 9 un/able areas ( e>?'s cru/1 #hf2 wave motions (1 #fh2 zones 9 di/ribution (1 #hf4 ,e>? relief1 repeat+ patt]ns 91 #bbc4 ,eck]t1 cit$1 #ahh4 ,effect ( contraction ^u a sph]ical body1 #ac4 ,egg-sp9n+ demon/ration ( e>? rigidity1 #bj4 8,elevation-crat]0 !ory ( volcanoes1 #ie1 #aci4 ,embankm5ts1 %ore1 #bdj4 ,embay$ coa/s1 #bea4 ,em]son1 ,b4 ,k41 cit$1 #ai4 ,end mora9es1 #cid4 ,engell1 ,m4 ,c41 cit$1 #bif4 ,englacial dbris1 #cic4 ,englacial drift1 #bgg1 #bgh4 ,entonnoirs1 #ahb4 ,entr5*m5t ( me&]s1 #agb1 #agc1 #agi4 ,eolian s&1 #bjf4 ,eolian s$im5ts1 #cj4 ,erosional uncon=mity1 #ec4 ,erosion cycle1 #aei4 ,erosion1 effect (1 9 add+ curves to l&scape1 #fe2 glacial1 9 contra/ ) normal wea!r+1 #cgg2 9 des]t1 #bad2 %ad[1 #bjf2 /ream1 z modifi$ by resi/ant rocks1 #agd4 8,erratic blocks01 #cjd4 ,eruptions1 ,/rombolian1 #aag2 ,vulcanian1 #aag1 #abe4 ,esc>pm5ts1 f faults1 #ei4 ,esk]s1 #caa1 #cae1 #caf1 #cfc4 ,e/es1 ,l4 ,a41 cit$1 #ic4 ,e/u>ies1 #bea4 ,etna1 eruption ( #affi1 #abb4 ,evolution1 doctr9e (1 9 connection ) fossils1 #ch4 ,evolution ( ideas conc]n+ ! e>?'s figure1 #i4 ,exfoliation1 #aea1 #bjc4 ,exp&$ foot glaci]s1 #chc1 #che4 ,exp]im5t1 to illu/rate relation ( e>?quake %ocks to f\ndations1 #hh4 ,exp]im5ts1 on fracture & fl[1 #dj1 #da2 = demon/ration ( e>?quakes1 #ha1 #hb4 ,exposures1 rock1 #df4 ,extrusive rocks1 #dfc4 ,fairbanks1 ,h4 ,w41 cit$1 #aee1 #agj1 #agd1 #bja1 #bje1 #bad1 #bbd1 #bdh1 #bdi1 #bej1 #bfj1 #cjb1 #cge1 #djf1 #dac1 #dbi4 ,fair*ild1 ,h4 ,l41 cit$1 #cci4 ,falls1 8,bridal veil01 #cgh4 ,falls1 ribbon1 #cgh4 ,fan1 alluvial1 #bac4 ,f>r+ton1 ,o4 ,c41 cit$1 #bi4 ,fault1 drag ^u1 #fj4 ,fault breccia1 #fj4 ,fault topography1 #fe4 ,faults1 #eh1 #ddj2 dur+ e>?quakes1 #ga2 e>?quake1 *ange 9 ?r[ ^u1 #gf1 #gg1 #gh2 e>?quake1 disappe> 9 loose mat]ials1 #gc2 e>?quake1 ( small displacem5ts1 #gd2 e>?quake1 plan (1 #gf1 #gh2 illusory nature (1 #ei2 me?ods ( detect+1 #ei2 po/-glacial1 #gd2 relation ( esc>pm5ts to1 #fj2 %[n by *anges 9 /rike & dip1 #fa2 %[n by (fsets1 #fa4 ,feldsp>s1 #def4 ,f5neman1 ,n4 ,m41 cit$1 #dbd1 #dbe4 ,fe/oons ( m\nta9 arcs1 #dce1 #dcf4 ,field ice1 #bhf4 ,field map1 geological1 #fb1 #fc4 ,figure ( ! e>?1 !1 #h4 ,figures1 e>li]1 ( ! e>?1 #ad2 e>?1 evolution (1 #ae4 ,figure t[>d :i* ! e>? is t5d+1 #ab4 8,fire girdle0 ( ! ,pacific1 #ih4 ,firn1 #cfi4 ,fissure eruptions1 ( volcanoes1 #aja4 ,fissures1 dur+ e>?quakes1 #ga2 e>?quake1 #gd2 9 connection ) volcanoes1 #ii-aja4 ,fissure spr+s1 #fa1 #aij1 #aie4 ,fjords1 #bij1 #cdj4 8,float copp]01 #cje4 ,flood$ portions ( cont95ts1 #ah4 ,flood pla91 #agh2 mann] ( grad+ (1 #afb4 ,floors ( hydrosph]e & atmosph]e1 #ah4 ,fl[1 exp]im5ts on1 #da2 zone (1 #dj4 ,fl[ texture1 ( extrusive rocks1 #cc4 ,fluviatile deposits1 #ce4 ,fluvio-glacial deposits1 #ca4 ,fluxion texture1 ( extrusive rocks1 #cc4 ,folds1 analysis (1 #ed2 comp>ison ( %apes (1 #dd2 mutilat$1 re/oration (1 #de2 pit*+1 #dc2 second>y1 #dd2 %apes (1 #dc4 ,fold topography1 #fe4 ,=bes1 ,j4 ,d41 cit$1 #bid4 ,=e-set b$s1 #afg4 ,=e/1 de/ruction (1 9 relation to agriculture1 #aef4 ,=mation ( lava res]voirs1 #adc4 ,=mations1 measurem5t ( ?ickness (1 #dh1 #di4 ,=t ,snell+1 on ,w>r5 ,riv]1 #cbg1 #cca4 ,fosses1 glacial1 #bha1 #cad2 9 connection ) peat bogs1 #dcj4 ,fracture control1 ( dra9age l9es1 #bbd4 ,fracture1 exp]im5ts on1 #da2 ( m9]als1 #dej2 zone (1 #dj1 #df4 ,fractures1 9 rocks1 %[n by rectil9e> l9es on map1 #fe2 sy/em (1 #ee4 ,free1 ,e4 ,e41 cit$1 #bbb4 ,free waves1 #bcb4 ,frett$ upl&1 #cgb1 #cgc4 ,fro/1 pry+ "w (1 #aeb4 ,fro/ action1 #bbc4 ,fro/ sn[1 #bhe4 ,full]1 ,m4 ,l41 cit$1 #aeg1 #aie4 ,fum]oles1 #ig4 ,gabbro1 #dfb4 ,gabl$ faade1 9 des]t l&scapes1 #bba1 #ddc4 ,gal5ite1 #dec4 ,gannett1 ,h5ry1 cit$1 #agh1 #chf4 ,gaps1 wat]1 #agf2 w9d1 #agf4 ,g>net1 #dei4 ,gauti]1 ,e4 ,f41 cit$1 #bba4 ,geikie1 ,a41 cit$1 #f1 #g1 #adh1 #agh1 #bdd1 #cah4 ,geikie1 ,james1 cit$1 #f1 #cah4 ,geoid1 dep>ture f sph]ical surface (1 #aj4 ,geological map1 #df1 #ed2 areal1 #fb1 #fc2 base (1 #fa2 field1 #fb1 #fc4 ,geological section1 #df1 #dg4 ,geology1 def9$1 #a4 ,geys]ite1 #aid4 ,geys]s1 #aia-aid2 effect ( plugg+ ) sod1 #aic2 9 relation to dra9age l9es1 #aia2 soap+ (1 #aid4 ,geysir1 #aib4 ,gilb]t1 ,g4 ,k41 cit$1 #ic1 #adh1 #aeg1 #agh1 #agi1 #aih1 #bba1 #bbd1 #bdj1 #bdd1 #bid1 #cdd1 #cde1 #cdg1 #cej1 #cee1 #cef1 #ceg1 #ceh1 #cei1 #cfb1 #cff1 #cgj1 #cha1 #dcd1 #ddf1 #ddg4 ,gjs1 volcano fissures 9 ,icel&1 #ii4 ,glacial anticyclone1 #bhd4 ,glacial deposits1 #cj1 #ca4 ,glacial fr+e1 ( ,grant ,l&1 #bhe4 ,glacial ,lake ,agassiz1 #cbe-cbh1 #cci4 ,glacial lakes1 at close ( ice age1 #cbj2 ( ,/4 ,lawr5ce ,valley1 #cbi4 ,glaciat$ regions1 aspects (1 #cjb2 *>act]i/ics (1 #cja2 contra/$ ) nonglaciat$1 #bii1 #cji4 ,glaciation1 conditions ess5tial to1 #bfa2 cycle (1 #bfc2 ,p]mo-,c>bonif]\s1 #bih4 ,glaciations1 foll[+ *anges 9 e>?'s figure1 #ae2 previ\s to 8ice age01 lit]ature (1 #cah4 ,glaci] broom1 ov] cont95tal ice1 #bhe4 ,glaci] cornices1 #cig4 ,glaci] deposits1 ^u its b$1 #cij4 ,glaci] dra9age1 #cig4 ,glaci] fl[1 #cij1 #djj2 data f accid5ts to ,alp9i/s1 #cib4 ,glaci] grav+s1 #cja1 #cai2 multiple records1 #cjd4 ,glaci] lobe lakes1 #daa4 ,glaci] milk1 #cih4 ,glaci] mills1 #bgh4 ,glaci] pavem5t1 #bgf4 ,glaci]s1 bir? (1 #cfi2 crevasses on1 #cia2 d5dritic1 #chc1 #che1 #chf2 gr9d+ tools (1 #bgf2 horse%oe1 #chc1 #chf1 #chg2 inh]it$ bas91 #chg-chi2 initiation (1 #bfb2 9 relation to w9d direction1 #bfb2 ma9 types (1 #bff2 m\nta91 cross sections (1 #cid2 m\nta91 exp&$-foot type1 #bfd2 m\nta91 l& sculpture by1 #cfg2 m\nta91 successive /ages1 #chc2 nivation1 #chg2 n\ri%m5t (1 #bfh-bgj2 pi$mont1 #chc1 #chd2 radiat+1 #chc1 #chf2 s5sitiv5ess to temp]ature *anges1 #bfc2 sracs1 #cia2 surface features (1 #cij2 tide wat]1 #bij1 #chf4 ,glaci] />s1 #cie4 ,glaci] tables1 #cie4 ,glaci] types1 successive1 dur+ wan+ glaciation1 #chc4 ,glaci] wells1 #bgh4 ,glassy texture1 ( extrusive rocks1 #cb4 ,gl5 ,roy1 #cbb1 #cci4 ,gl9t1 #dji4 ,gl9t lakes1 #djh1 #dji4 ,gneiss1 #dfe4 ,gneiss b&+1 #ca4 ,goe!1 cit$ on volcano /ructure1 #aci4 ,gold1 ,e41 cit$1 #bid4 ,gold?wait1 ,j4 ,w41 cit$1 #bei1 #cbj1 #cda1 #cde1 #cea4 ,gondwana ,l&1 #af4 ,gorges1 ?r\gh rock b>s1 #cgh4 ,grabau1 ,a4 ,w41 cit$1 #cfa1 #cff4 ,grad+ ( flood pla91 #afb4 ,gr& ,caon ( ! ,colorado1 #adf1 #afi1 #agd1 #bae1 #ddc4 ,gr& ,riv] outlet1 #ccc4 ,granite1 #dfb2 dome /ructure 91 #aeb1 #aeg4 ,granite domes1 #bba4 ,granitic texture1 ( igne\s rocks1 #cc4 ,grats1 #cgc4 ,gravel1 kame1 #caj4 8,gravel pi$mont01 #bad4 ,great ,bas91 #aij1 #aih1 #dci4 ,great ,lakes1 probable future (1 #cdg1 #cdh2 subm]g5ce ( c]ta9 %ores (1 #cdi1 #cej4 ,great ,ross ,b>ri]1 #bhb4 ,great ,salt ,lake1 #aii2 fluctuations ( level (1 #aih4 ,gre51 ,w4 ,l[?ian1 cit$1 #ai4 ,gregory1 ,j4 ,w41 cit$1 #aa1 #ai1 #dci1 #ddf4 ,groov$ upl&1 #cgb1 #cgc4 ,gross1 ,h41 cit$1 #bid4 ,grossman1 cit$1 #bfh4 ,grottoes1 sea1 colors (1 #beh4 ,gr\nd wat]1 #ahj2 desc5t (1 9 relation to jo9ts1 #aha4 ,gr\nd wat] lakes1 #dbd4 ,grund1 ,a41 cit$1 #aie4 ,gullies1 e>ly /ages (1 #afj4 ,gulliv]1 ,f4 ,p41 cit$1 #bdd1 #cai4 ,gully+ process1 />t$ by de=e/ation1 #aef4 ,gypsum1 #dee4 ,hade1 on faults1 #ei4 ,hague1 ,arnold1 cit$1 #aif4 ,halemaumau1 ,kilauea1 #ajg1 #ajh4 ,hamilton1 ,sir ,william1 cit$1 #abh4 ,hang+ valleys1 #cgh4 ,h>dness1 ( m9]als1 #dea4 ,h>wood1 ,w4 ,a41 cit$1 #bid4 ,haug1 ,e41 cit$1 #g1 #acc1 #baa4 ,haughton1 ,samuel1 cit$1 #ef4 ,hawaii1 lava domes (1 #aje2 lava surfaces (1 #aac2 map (1 #ajf2 section ?r\gh1 #ajf4 ,hayes1 ,c4 ,w41 cit$1 #aef4 ,headl&s1 not*$1 #cda4 ,heave1 ( faults1 #ei4 ,hebrews1 conception ( ! univ]se1 #i4 ,h$91 ,sv51 cit$1 #bba4 ,heilpr91 ,a41 cit$1 #adh4 ,heim1 ,a41 cit$1 #ed4 ,heligol&1 #bcf4 ,hell&1 ,a41 cit$1 #ii4 ,hematite1 #deb4 ,hemicycles1 ( glaciation1 #bfc1 #bfd4 ,h]culaneum1 buri$ b5ea? mud fl[s1 #aci4 ,hess1 ,h41 cit$1 #bfg1 #bgb1 #bid1 #cic1 #djj4 ,high pla9s1 #dce2 orig9 (1 #bai4 ,hilg>d1 ,e41 cit$1 #bbb4 ,h+e l9es1 ( uptilt1 #cdd-cdg4 ,hit*cock1 ,c4 ,h41 cit$1 #ajf1 #adg1 #dcd4 ,hobson1 ,b41 cit$1 #abj4 ,hog>?1 ,william1 cit$1 #agj4 ,hog>?ian l9e ( beauty1 9 l&scapes1 #agj-aga4 8,hog backs01 #ddb4 ,holmes1 ,w4 ,h41 cit$1 #dda4 ,horns1 #cgd4 ,horse%oe glaci]s1 #chc1 #chf1 #chg4 ,hot spr+s1 #aia2 colors 91 due to alg1 #aid4 ,hovey1 ,e4 ,o41 cit$1 #acf1 #acg1 #adh4 ,hovey1 ,h4 ,c41 cit$1 #ahc1 #aie4 ,h[*91 ,w41 cit$1 #bih4 ,h[e1 ,e41 cit$1 #adj4 ,h[ell1 cit$1 #cbe4 ,hudson ,riv]1 n>r[s (1 #agd4 ,hudsonian *annel1 #beb4 ,hummocks1 on pack ice1 #bhf4 ,humphrey1 ,r4 ,l41 cit$1 #ij1 #ic4 ,humphreys1 cit$1 #djd4 ,humus1 9 relation to wea!r+1 #aef4 ,hunt+ton1 ,ellswor?1 cit$1 #baf1 #bag1 #bba1 #bbb4 ,hus1 ,h4 ,t4 ,a4 de ,l41 cit$1 #ahc4 ,hydration1 #aea4 ,hydrosph]e1 #h4 ,hypo!sis1 ! value (1 #f2 ,laplacian1 ( ! univ]se1 #bj4 ,iceb]gs1 #bif2 ,ant>ctic1 #bib1 #bic2 ,ant>ctic1 =mation (1 #bib2 blue1 #bib2 mann] ( =mation (1 #bia1 #bib2 nor!rn1 #bia4 ,ice caps1 pr(iles (1 #bfg1 #bfh2 sculpture1 #chj4 ,ice-damm$ lakes1 #cba1 #cbc1 #daj1 #daa2 9 ,/4 ,lawr5ce ,valley1 #cci2 ( ,scotti% gl5s1 #cbb4 ,ice floes1 #bhg4 ,icel&1 fissure eruptions (1 #ajb4 ,ice pyramids1 #cie4 ,ice ramp>ts1 #dca-dcd2 mann] ( =mation (1 #dcc4 ,igne\s rocks1 #cj2 textures (1 #cb4 ,imlay outlet1 #ccb4 ,inbreak1 ( lava surface1 #ajg4 ,incis$ topography1 #cja4 ,inh]it$ bas9 glaci]1 #chg-chi4 ,int]lobate mora9es1 #cad4 ,int]-pluvial p]iods1 #aih4 ,intricate patt]n ( riv] et*+s1 #aeh4 ,intrusive rocks1 #cb1 #dfb4 ,isl&s1 l&-ti$1 #bda2 /eep rocky1 due to subm]g5ce1 #beb4 ,isobases1 #cdg4 ,isocl9al folds1 #db4 ,iso!rmal zone ( atmosph]e1 #bgj4 ,jagg]1 ,t4 ,a41 ,jr41 cit$1 #adh4 ,jamieson1 ,t4 ,f41 cit$1 #bba1 #cbb1 #cci4 ,jeannette explor+ exp$ition1 #bhg1 #bie4 ,j5s51 ,h4 ,i41 cit$1 #aaj1 #aac1 #adg4 ,johnson1 ,d4 ,w41 cit$1 #g1 #adh4 ,johnson1 ,w4 ,d41 cit$1 #gg1 #bac1 #bai1 #bbj1 #bbb1 #cgj1 #cha4 ,john/on-,lavis1 ,h4 ,j41 cit$1 #hg1 #aca1 #acb1 #acd1 #ach1 #adg1 #adh4 ,jo9t blocks1 9 ,niag>a lime/one1 #cec4 ,jo9t plane1 seat ( fro/ action1 #cgj4 ,jo9ts1 #ef2 effect on surface features1 #eg2 clos$ dur+ e>?quakes1 #gf2 composite nature (1 #eh2 composite gr\ps (1 #eg2 disord]ly1 #eg2 displacem5ts ^u1 #eh2 ma/]1 #ef2 space int]vals (1 #eh2 sets (1 #ee2 sy/em (1 #ee4 ,jo9t s]ies1 comb9ations (1 #ef4 ,jo9t sy/ems1 #ff4 ,jorullo1 bir? 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relation to rock ar*itecture1 #afa2 me%es (1 #afa4 ,riv]s1 braid$1 #bhj2 cross sections (1 9 successive /ages1 #agb2 dr[n$1 #bea1 #cdj2 e>ly aspects (1 #aei2 life begun 9 uplift1 #aei2 life hi/ories (1 #aeh2 motive p[] (1 #aeh2 rejuv5at$1 #agc1 #agd2 subm]g$ *annels (1 #beb2 swoll5 dur+ melt+ ( cont95tal glaci]s1 #cbj2 tribut>y1 accordant1 #cgg2 "y1 #aei1 #afj4 ,riv] t]races1 #afe1 #agh4 ,riv] valley1 longitud9al section (1 #afa4 ,ro*es m\tonnes1 #bgf1 #cja1 #cfg4 ,rock b>s1 #cgg2 cut ?r\gh by gorges1 #cgh4 ,rock bas9 lakes1 #cgf1 #cgg1 #djj1 #dab4 ,rock cleavage1 #dd4 8,rock glaci]s01 #aec4 8,rock+ /ones01 #cjf4 ,rock mantle1 #aee2 relation to topography1 #aef4 ,rock p$e/als1 #cha4 ,rock t]races1 #bae4 ,rocks1 cla/ic1 #cj2 corrosion (1 #aef2 description ( "s common1 #dfb-dff2 extrusive1 #cb1 #dfc2 igne\s1 #cj2 igne\s1 textures (1 #cb2 igne\s1 massive /ructure (1 #ca2 intrusive1 #cb1 #dfb1 #dfc2 lam9at$ /ructure (1 #ca2 m>ks ( orig9 (1 #cj2 metamorphic1 #cj1 #ca1 #dfe2 residual1 #cj2 s$im5t>y1 #cj2 s$im5t>y1 ( *emical precipitation1 #dfd2 s$im5t>y1 ( me*anical orig91 #dfc2 s$im5t>y1 ( organic orig91 #dfd2 s$im5t>y1 r\nd$ gra9s (1 #ca2 volcanic1 #cb4 ,ross ,b>ri]1 #bhb4 ,rudolph1 ,e41 cit$1 #ib4 ,rudski1 ,m4 ,p41 cit$1 #ai4 ,russell1 ,i4 ,c41 cit$1 #abf1 #adg1 #adh1 #age1 #agh1 #bbb1 #bic1 #bid1 #bif1 #cha1 #chd1 #dad1 #dbd1 #dbe4 ,/4 ,an?ony ,falls1 recession (1 #cbg1 #ced4 ,/4 ,david's gorge1 ne> ,niag>a1 #ceb1 #cei1 #cfj1 #cfc4 ,/4 ,go>s1 on ,rh9e1 #afi4 ,sa9t ,m>t91 cit$1 #dcf4 ,/4 ,paul's rocks1 a dissect$ volcano1 #ada4 ,sali5ts1 ( newly incis$ upl&1 #afi4 ,sal9es1 #dbc4 ,salisbury1 ,r4 ,d41 cit$1 #aef1 #afj1 #bje1 #bbb1 #bic1 #bie1 #bih1 #cjj1 #cje1 #cac1 #cah1 #cai1 #cci1 #dbd4 ,salton s9k1 #dbj4 ,s&1 bea*1 #bjf2 eolian1 #bjf2 volcanic1 #abb4 ,s& bla/1 natural1 #bjd4 ,s& cones1 #hd4 8,s& devils01 #bji4 ,s&/one1 #dfd4 ,s& /orms1 #bji4 ,santa ,catal9a1 #bci1 #beg4 ,sapp]1 ,k41 cit$1 #aaa1 #adg1 #adh4 ,s>as91 ,p4 & ,f41 cit$1 #bdh4 ,s>deson1 ,f4 ,w41 cit$1 #cbg1 #cci4 ,sauc] lakes1 #dae1 #daf4 ,sawa ,lake1 ( ,p]sian des]t1 #aii4 ,scal+1 #aea4 ,scape colks1 #bgg4 ,sc>s1 f dissection ( volcanoes1 #adb2 me&]1 #afe4 ,s*i/1 *lorite1 #dfe2 mica1 #dfe2 s]icite1 #dfe2 talc1 #dfe4 ,s*i/osity1 #ca4 ,s*rad]1 cit$1 #dcf4 ,s*ratt51 #ahh4 ,scidmore1 ,e4 ,r41 cit$1 #gj4 ,scoriace\s texture1 ( extrusive rocks1 #cb4 ,scott1 ,i4 ,d41 cit$1 #daa1 #dgj4 ,scott1 ,r4 ,f41 cit$1 #bhb1 #bie4 ,scott1 ,w4 ,b41 cit$1 #f1 #fj1 #gb1 #bei1 #bgd1 #cge4 8,scree01 #aeb4 ,scrope1 ,p41 cit$1 #if1 #abd1 #adf4 ,sea caves1 #bcd2 elevat$1 #bdh4 ,sea coves1 #bcc4 ,sea ice1 #bhf1 #bib4 ,seaquakes1 #fi2 di/ribution (1 #gj2 d[nw>d movem5t ( sea floor dur+1 #ha2 numb] & magnitude (1 #ha4 ,seasonal lakes1 #ahi1 #dbb4 ,section1 geological1 #df1 #dg2 across m\nta9 wall ab\t des]t1 #bab4 ,s$]holm1 ,j4 ,j41 cit$1 #cae4 ,s$im5t>y rocks1 #cj2 ( *emical precipitation1 #dfd2 ( me*anical orig91 #dfc2 ( organic orig91 #dfd4 ,seismic sea wave1 #fi2 ,japan1 #ahif1 #gj4 ,seismotectonic l9es1 #hg4 ,sekiya1 ,s41 cit$1 #ada1 #adh4 ,sracs1 #cia4 ,s]apeum1 at ,pozzuoli1 #bed4 ,s]icite s*i/1 #dfe4 ,s]ies1 con=mable1 #ea2 uncon=mable1 #ea4 ,s]p5t9e1 #dfj4 ,%ackleton1 ,sir ,erne/1 cit$1 #ag1 #bhb1 #bhc1 #bib1 #bie4 ,%ad[ erosion1 #bjf4 ,%ad[ wea!r+1 #bjc4 ,%ale1 #dfd4 ,%al]1 ,n4 ,s41 cit$1 #g1 #aeg1 #bdd1 #cjf1 #cag1 #cai4 ,%apes ( rock folds1 #dc4 ,%aw1 ,e4 ,w41 cit$1 #dbe4 ,%e>+1 9 folds1 #de4 8,%eep backs01 #bgf4 ,%elf1 cont95tal1 #ah1 #ai4 ,%elf ice1 #bha1 #bhb1 #bhc2 ,ant>ctic1 #bhi1 #bij2 ( ice age1 #cag4 ,%]z]1 ,w4 ,h41 cit$1 #bid4 ,%ields1 ( li?osph]e1 #dcf4 ,%+le1 #bci4 ,%oal wat] deposits1 #cf4 ,%ore curr5t1 "w (1 #bcg1 #bch4 ,%ore l9es1 elevat$1 #cdj2 migration ( l&w>d ) uplift1 #bea4 ,side delta lakes1 #dah1 #dai4 ,sid]ite1 #def4 ,sieb]g1 ,a41 cit$1 #ib4 ,sieg]1 ,r41 cit$1 #bei4 ,silice\s lava1 visc\s1 #ajc4 ,silice\s s9t]1 #aid4 ,sills1 #adb4 ,s9clair1 ,w4 ,j41 cit$1 #aeb4 ,s9k lakes1 #dba4 ,s9ks1 9 lime/one1 #ahb4 ,s9t]1 calc>e\s1 #ahd2 silice\s1 #aid4 ,s9t] columns1 =mation (1 #ahe4 ,s9t] deposits1 #ahd4 ,sjgr51 ,otto1 cit$1 #bbe4 ,skaptr fissure 9 ,icel&1 #ii4 ,skyl9e1 /raight1 ( mature upl&1 #agj4 ,slate1 clay1 #dff4 ,sli*t]1 ,c4 ,s41 cit$1 #aie4 ,slick5sides1 on fault1 #fj4 ,smi?1 ,george ,otis1 cit$1 #agc4 ,smi?sonite1 #def4 8,smoke0 ( volcanoes1 nature (1 #abh4 ,smy?1 ,c4 ,h41 ,jr41 cit$1 #aeg4 ,snake riv]1 ,idaho1 lava pla9s (1 #ajb4 ,snick]s ,gap1 #agg4 ,sn[1 ,b4 ,w41 cit$1 #aic4 ,sn[b]gs1 #bib1 #bic4 ,sn[drift sites1 #cfh4 ,sn[ l9e1 #bfa4 ,soil fl[1 #aec1 #aeg4 ,soil /rip+1 #aed4 ,solfat>a condition ( volcanoes1 #ig4 ,solg]1 ,f41 cit$1 #bbb4 ,solifluxion1 #aec1 #aeg4 ,sonkl>1 cit$1 #chf4 ,spallanzani1 cit$1 #aae4 ,spatt] cones1 #ajd4 ,speculative philosophy vs4 obs]vational geology1 #e4 ,sp5c]1 ,j4 ,w41 cit$1 #bfj1 #cdd1 #cej1 #cec1 #cff4 ,spe?mann1 ,h41 cit$1 #bfg4 ,sphal]ite1 #dec4 ,sph]ulites1 #cc4 ,sph]ulitic texture1 ( igne\s rocks1 #cc4 ,sph9x1 erosion by natural s& bla/1 #bje4 ,spits1 #bdj4 ,spitzb]g51 #aed4 ,spr+s1 fissure1 #aij1 #aie2 surface1 #aha2 !rmal1 #aij4 ,/ability1 n ! ord] ( nature1 #d4 ,/acks1 #bcc2 elevat$1 #bdi1 #cdc4 ,/age ( adolesc5ce1 #afi1 #agj4 ,/airway1 cascade1 #cgf4 ,/alactites1 gr[? (1 #ahd4 ,/alagmites1 =mation (1 #ahe4 ,/aurolite1 #dfj4 ,/eppes1 #bae4 ,/ill riv]1 ( ,connecticut1 hi/ory (1 #cch4 ,/one1 ,g4 ,h41 cit$1 #bec1 #bfj1 #cae1 #cai4 8,/one g+]01 #bjh4 8,/one lattice01 #bje1 #bjf4 8,/one riv]s01 #aec4 ,/rahan1 ,a41 cit$1 #cah4 ,/r& lakes1 #dbd4 ,/rata1 con=mable1 #ea2 contortions (1 #dj4 ,/ra?s1 #dbh4 ,/reak1 ( m9]als1 #dea4 ,/ream capture1 #agi4 ,/ream1 me&]+1 cross section (1 #afc2 braid$1 #bhj2 int]mitt5t1 #ahj4 ,/ream velocity1 det]m9$ by gradi5t1 #aeh4 ,/rike1 #df4 ,/rip$ gr\nd1 #aed4 ,/rokr1 #aic4 ,/rombolian eruptions1 #aag4 ,/romboli1 c9d] cone (1 #aae2 exc5tric crat] (1 #aae2 explanation ( eruptions 91 #aaf1 #aag4 ,/ructure1 cross-b$d$1 #cg4 ,subm]g$ *annels1 ( riv]s1 #beb4 ,subm]g5ce ( l&1 dur+ e>?quakes1 #hj4 ,suess1 ,e41 cit$1 #ai1 #adb1 #bei1 #bgg1 #dbe1 #dcf1 #dcg1 #dch1 #ddf4 ,suffioni1 arrangem5t on faults1 #hg4 ,supan1 ,a41 #dbj1 #dbd4 ,surface mora9es1 #bgg4 ,surface spr+s1 #aha4 8,swall[ holes01 #ahb1 #dbb4 ,swamp l&s1 dra9$ dur+ e>?quakes1 #hc4 ,swe9fur?1 ,g41 cit$1 #bbb4 ,sy5ite1 #dfb4 ,symbols1 ,t41 to express /rike & dip1 #dh4 ,syncl9al folds1 #db4 ,syncl9es1 #db4 ,sy/em ( fractures1 #ee4 ,taal volcano1 d\ble explosive eruption ( #aiaa1 #abj1 #aba4 ,table m\nta9s1 orig9 (1 #aab4 ,takyr1 #baf4 ,talc1 #dfj4 ,talc s*i/1 #dfe4 ,talmage1 ,j4 ,e41 cit$1 #bba4 ,talus1 #aeb1 #aec1 #bae4 ,tangi]-,smi?1 ,w4 ,s41 cit$1 #bfj4 ,t>r1 ,r4 ,s41 cit$1 #gg1 #ib1 #bcc1 #bfj1 #bie1 #cja4 ,taylor1 ,f4 ,b41 cit$1 #bei1 #ccj1 #cci1 #cdb1 #cdc1 #cdf1 #cej1 #cee1 #cff4 ,tectonic lakes1 #dbd4 ,temp]ature1 diurnal *anges (1 9 des]ts1 #bjb4 ,temple ( ,jupit] ,s]apis1 oscillations ( level (1 #bed1 #bee4 ,t]m9al mora9e1 ( ,plei/oc5e glaciations1 #bih1 #bii4 ,t]m9al mora9es1 ( m\nta9 glaci]s1 #cid4 ,t]rac$ valleys1 #cbj1 #cba4 ,t]races1 built1 #bce2 coa/1 #hj1 #bce1 #cda2 riv]1 #afe1 #agh1 #cbj1 #cba2 rock1 #bae4 ,t]ra ,rossa1 ( ,k>/ region1 #ahh4 ,tessellat$ pavem5t1 f soil fl[1 #aed4 ,te?ys1 ocean (1 #af4 ,tetrah$ron1 reciprocal relations ( antipodal p>ts1 #ac2 truncat$1 t[>d :i* e>? is t5d+1 #ab4 ,tetrah$rons1 tw91 #af4 ,?aw wat]1 soil fl[ 9 pres5ce (1 #aec4 ,!ory1 evolv$ f work+ hypo!sis1 #f2 mixture ) obs]vation1 on maps1 #fc4 ,!rmal spr+s1 #aij4 ,?ickness ( =mations1 #fe4 ,?ompson1 ,b]?a1 cit$1 #aee4 ,?omson & ,tait1 cit$1 #bi4 ,?omson1 ,wyville1 cit$1 #bif4 ,?orodds51 ,?41 cit$1 #ajc1 #abc1 #adg1 #bfg4 ,?r[1 on faults1 #ei4 ,?ru/s1 #de4 8,tidal waves01 #gj4 ,tides1 effect on a fluid e>?1 #bj4 ,tidewat] glaci]s1 #bij1 #chf4 ,till1 #ca1 #caj4 ,tillite1 #ca4 ,till pla9s1 #caa4 ,t9ds1 #chj1 #cha4 ,tivoli1 trav]t9e (1 #ahd4 ,tombolas1 #bda4 ,tongues1 ice1 on m>g9 ( cont95tal glaci]s1 #bgb4 ,topographic maps1 #fa2 prep>ation (1 #dfg4 ,topography1 built up1 #cja2 con/ructional1 #cji2 de/ructional1 #cji2 fault1 #fe2 fold1 #fe2 incis$1 #cja2 knob & bas91 #cad4 ,top-set b$s1 #afg4 ,t\rmal9e1 #dfj4 ,t[]1 ,w4 ,s41 cit$1 #agh4 ,tra*yte1 #dfc4 ,transgression1 ( ! sea1 #cg4 ,transp>5cy1 ( m9]als1 #dea4 ,trav]t9e1 #ahd1 #dfd4 ,trees1 h[ affect$ by advanc+ lava1 #acc2 und]m9$ on /ream me&]s1 #afd4 8,trellis dra9age01 #age4 ,tr\ghl9e1 ( a syncl9e1 #db4 ,trunk *annels ( desc5d+ wat]1 #aha4 ,tsunamis1 #gj4 ,t symbols1 to express /rike & dip1 #dh4 ,tufa1 calc>e\s1 #dfd4 ,tunnels1 lava1 #aaa1 #aab1 #abe4 ,tw9 tetrah$rons1 #af4 ,tyndall1 ,john1 cit$1 #aib1 #aif4 ,udd51 ,j4 ,a41 cit$1 #bbb4 ,uncon=mable s]ies1 #ea4 ,uncon=mity1 #fe2 episodes 9 hi/ory (1 #eb2 mean+ (1 #ea4 ,und]fold+1 ( e>?'s %ell1 #dcg4 ,und]gr\nd wat]1 #ahj4 ,und]t[1 #bcf4 ,un/able erosion remnants1 9 8driftless area01 #cjj4 ,upham1 ,w>r51 cit$1 #cbe1 #cbg1 #cci1 #cdd1 #cej4 ,upl&1 frett$1 #cgb1 #cgc2 groov$1 #cgb1 #cgc2 maturely dissect$1 #agj2 mature1 unfavorable to comm]cial developm5t1 #aga2 newly incis$1 #afi2 p>tially dissect$1 #afj2 progressive inve/m5t (1 by cirques1 #cgd4 ,uplift1 m>ks (1 on coa/s1 #bde2 sudd51 ( coa/s1 #bdg4 ,uprais$ cliffs1 #bdi4 ,uptilt1 9 bas9 ( ,lake ,agassiz1 #cej2 ( glaciat$ area1 evid5ce t x cont9ues1 #cdh-cej2 ( glaciat$ area1 suppos$ nature (1 #cdd-cdg4 ,u-%ap$ valleys1 #cgd4 ,usu-san 7,new ,m\nta971 bir? (1 #if4 ,valley mora9e lakes1 #djj1 #dac4 ,valleys1 hang+1 #cgh2 ( ,v-=m1 #agb2 ,u-%ap$1 #cgd4 ,valley tra9s1 #caa1 #cii4 ,van ,hise1 ,c4 ,r41 cit$1 #ed4 ,v>ni%1 des]t1 #bja4 ,veat*1 ,a4 ,c41 cit$1 #dah1 #dbe4 ,v]beek1 ,r4 ,d4 ,m41 cit$1 #ajj1 #adb1 #adg1 #adh4 ,vesicul> texture1 ( extrusive rocks1 #cb4 ,victoria ,falls1 #bbe4 ,v9c5tius ( ,beauvais1 cit$1 #i4 ,volcanic a%1 #abb4 8,volcanic bombs01 #aba4 ,volcanic du/1 #abb4 ,volcanic eruptions1 dur+ *anges 9 e>?'s figure1 #ae4 ,volcanic lakes1 #dbd4 ,volcanic m\nta9s1 ( eject$ mat]ials1 #aae2 ( exudation1 #id4 ,volcanic necks1 #adj4 ,volcanic pipes1 #adj4 ,volcanic plugs1 #aci1 #adj4 ,volcanic projectiles1 #aba4 ,volcanic rocks1 #cb4 ,volcanic s&1 #abb4 ,volcano belts1 ( ! e>?1 #ih4 ,volcano1 def9ition (1 #ie4 ,volcano1 eruption 9 #ahhh1 #aah1 #abj1 #adg2 hi/ory (1 #aah1 #aai4 ,volcanoes1 active1 #ig2 arrangem5t ov] fissures1 #ii2 bir? (1 #if2 cone-produc+ p]iod (1 #abg2 convulsive eruptions (1 #aje2 crat]-produc+ p]iod (1 #abh2 dissection (1 #aci1 #adh2 dormant1 #ig2 e>ly views conc]n+1 #ie2 8elevation-crat]0 !ory (1 #ie2 explosive eruptions (1 #aje2 ext9ct1 #ig2 fissure eruptions (1 #aja2 location at fissure int]sections1 #ajj2 map (1 9 ,java1 #ajj2 migration ( v5t along fissure1 #aja1 #abd2 misconceptions conc]n+1 #id2 mud fl[s aft] eruptions1 #ach2 ( ,gulf ( ,gu9ea1 #aja2 reg>d$ z reta9+ walls1 #abd1 #abe2 relation to m\nta9 ranges1 #add2 sequ5ce ( ev5ts )9 *imney (1 dur+ eruption1 #acd1 #ace2 solfat>ic activity (1 #ig2 ?ree types (1 #aje4 ,v-%ap$ valley1 #agb4 ,vulcanello1 #aai4 ,vulcanian eruptions1 #aag1 #abe4 ,walt]%aus51 ,s4 von1 cit$1 #adh4 ,wal!r1 ,johannes1 cit$1 #bja1 #bjb1 #bjc1 #bjd1 #bje1 #bjf1 #baa1 #bae1 #bba4 ,w&]+ dunes1 #bji4 ,w>r5 riv]1 #daf4 8,wa%es01 #bac4 ,wat]1 d]angem5t ( fl[ dur+ e>?quakes1 #hc2 gr\nd1 #ahj2 p]colat+1 rle (1 #adi2 runn+1 e>? features %ap$ by1 #afi2 %ot up 9 %eets dur+ e>?quake1 #hc2 ?aw1 soil fl[ 9 pres5ce (1 #aec4 ,wat] gaps1 #agf4 ,wat] pipes1 buckl$ 9 gr\nd1 dur+ e>?quakes1 #ge4 ,wat] table1 #ahj2 extreme dep? (1 #bja1 #bjc4 ,wat] wave1 effect ( break+ on %ore1 #bcc2 free1 #bcb2 motion (1 #bca4 ,watson1 ,t4 ,l41 cit$1 #bei4 ,wave1 wat]1 ! motion (1 #bca4 ,wave base1 #bcb4 ,wave l5g?1 #bca4 ,wea!r+1 c>bonization1 #aea2 *emical1 #adi2 *emical ag5ts (1 #adi2 dry1 #bja2 exfoliation1 #aea2 fro/ action1 #aeb2 hydration1 #aea2 9 relation to climate1 #aej2 int]nal1 9 des]ts1 #bja2 me*anical1 #adi2 ( li?osph]e surface1 #bi2 %ad[1 #bjc2 sph]oidal1 #aej1 #aea2 two contra/$ processes (1 #adi4 ,w$ 7,wadi71 #bab1 #bac1 #bad4 ,we$1 ,w4 ,h41 cit$1 #aif1 #dda1 #ddg4 ,we/ ,indies1 seismotectonic l9es (1 #hh4 ,:eel]1 ,w4 ,h41 cit$1 #bdd4 ,:irlpool bas91 at ,niag>a1 #cei2 excavation (1 #cfj4 ,:itbeck1 ,r4 ,h41 cit$1 #cai4 ,:ite1 ,david1 cit$1 #cah4 ,willis1 ,bailey1 cit$1 #de1 #ed1 #aeg1 #bfj1 #cah4 ,w9*ell1 ,n4 ,h41 cit$1 #ced4 ,w9d1 9 relation to location ( glaci]s1 #cgg2 9 relation to m\nta9 glaci]s1 #cfg4 ,w9d di/ribution ( sn[1 #cfg4 ,w9d gaps1 #agf4 ,w9dkant51 #bje4 ,w9d poles1 ( ! e>?1 #bfc2 ( e>?1 e>li]1 #big4 ,w9t]gre5 ,flats1 site ( captur$ fall1 #ceh4 ,wiscons9 diamonds1 #cjg1 #cjh4 ,woodwor?1 ,j4 ,b41 cit$1 #gd1 #cea4 ,worce/]1 ,dean ,c41 cit$1 #if4 ,work+ hypo!sis1 #f4 ,workman1 ,fanny ,bullock1 cit$1 #bid4 ,workman1 ,w4 ,h41 cit$1 #bid4 ,wright1 ,f4 ,e41 cit$1 #cea4 ,yell[/one ,national ,p>k1 #cc1 #aia1 #aic1 #aid4 ,yosemite ,valley1 #ei1 #aeb4 ,"y riv]s1 #aei1 #afj4 ,zahn1 ,g4 ,w4 von1 cit$1 #bdd4 ,zigzag ranges1 due to plung+ folds1 #ea4 ,zittel1 ,k4 v41 cit$1 #ai4 ,zone ( div]se displacem5t1 #dci4 ,zone ( fl[1 #dj1 #adc4 ,zone ( fracture1 #dj1 #df4 ,zones1 ( deposition1 surr\nd+ des]t1 #baf1 #bag2 upp] & l[] cl\d1 #bfh1 #bfi4 ,pr9t$ 9 ! ,unit$ ,/ates ( ,am]ica4 ,,footnotes3 #a ,italian = m\?2 plural boc*i4 #b ,^! models & ! cont\r+ app>atus are n[ manufactur$ = ! use ( s*ools & colleges by ,eb]ba* & ,son1 ,ann ,arbor1 ,mi*4 #c ,?is clay is manufactur$ by ! ,a4 ,h4 ,abbott ,company1 art deal]s1 ,waba% ,av5ue1 ,*icago4 #d ,numb]s 9 p>5!sis ref] to pages 9 ?is book1 :]e fur!r in=mation is to be f\nd4 99 99 99 99 99 99 ,transcrib]'s note3 --,obvi\s typographical errors h be5 sil5tly correct$4 ,all o!r v>iations 9 spell+ punctuation & acc5ts h be5 left un*ang$4 --,a bord] has be5 add$ to plates4