,transcrib] ,note ,text emphasis d5ot$ z ,italics & ,bold4 ,:ole & fractional numb]s z #abc-d_/e4 ,! ,cambridge ,manuals ( ,sci5ce & ,lit]ature ,,rocks ,,& ,,_! ,,orig9s ,,cambridge ,,univ]sity ,,press ,london3 ,,fett] ,,lane1 ,e4,c4 ,c4 ,f4 ,,clay1 ,manag] ,illu/ration ,ed9burgh3 #ajj1 ,,pr9ces ,,/reet ,london3 ,,william ,,wesley ,,son1 #bh1 ,,essex ,,/reet1 ,,/r& ,b]l93 ,a4 ,,a%] ,,& ,,co4 ,leipzig3 ,f4 ,a4 ,,brockhaus ,new ,york3 ,g4 ,p4 ,,putnam',s ,,sons ,bombay & ,calcutta3 ,,macmillan ,,& ,,co41 ,ltd4 ,all rights res]v$ ,,rocks ,,& ,,_! ,,orig9s ,,by ,,gr5ville ,a4 ,j4 ,,cole ,pr(essor ( ,geology 9 ! ,royal ,college ( ,sci5ce = ,irel& ,cambridge3 at ! ,univ]sity ,press #aiab ,cambridge3 ,,pr9t$ ,,by ,,john ,,clay1 ,m4,a4 ,,at ,,! ,,univ]sity ,,press ,) ! exception ( ! coat ( arms at ! foot1 ! design on ! title page is a reproduction ( "o us$ by ! e>lie/ kn[n ,cambridge pr9t]1 ,john ,sib]*1 #aeba ,,preface ,?is little book is int5d$ = ^? :o are n speciali/s 9 geology1 & x may p]haps be accept$ z a contribution = ! g5]al read]4 ,to all :o are int]e/$ 9 ! e>?1 ! /udy ( rocks is an important bran* ( natural hi/ory4 ,if detail$ works on petrology are to be consult$ lat]1 ,f4 ,w4 ,cl>ke's ,data ( ,geo*emi/ry 7,bullet91 ,u4,s4 ,geological ,survey1 ed4 #b1 #aiaa7 mu/ on no acc\nt be ov]look$4 ,its num]\s ref]5ces to publi%$ pap]s1 & ! att5tion giv5 to rock-orig9s1 make x a wor?y companion to ,c4 ,doelt]'s ,petrog5esis4 ,_m ?+s h p]=ce be5 omitt$ f ! pres5t essay4 ,x seem$ unnecess>y to review ! ,c>bonace\s rocks1 s9ce ! mo/ important ( ^! h be5 admirably dealt ) 9 ,e4 ,a4 ,n4 ,arb]'s ,natural ,hi/ory ( ,coal1 publi%$ z a volume 9 ?is s]ies4 ,i %\ld l to h describ$ occurr5ces ( rock-salt1 ( massive gypsum1 & o!r products ( arid l&s1 :]e black alkali poisons ! surface1 & ! casual pools are fr+$ ) :ite & crumbl+ cru/s4 ,rock-taluses1 & all ! v>i$ alluvium c>ri$ seaw>d z ! outwa% ( cont95tal l&1 well des]ve a *apt] to !mselves4 ,b !re is really no end to ! subject1 :i* embraces all ! accumulative processes ( ! e>?4 ,a few vacation-j\rneys1 judici\sly plann$ out1 tea* u t text-books are m]ely signpo/s to set u on :at is believ$ to be ! way4 ,:5 ! pa? ent]s ! great =e/1 or rises above gre5 lakelets to ! crags1 we f9d !re ^? :o w5t be=e u1 po9t+ to unconqu]$ l&s4 ,g4 ,a4 ,j4 ,c4 ,royal ,college ( ,sci5ce = ,irel&1 ,dubl94 ,febru>y #aiab4 ,,cont5ts ,,*ap4 ,,page ,li/ ( ,illu/rations viii ,i4 ,on ,rocks 9 ,g5]al #a ,li/ ( ! common ,m9]als t =m ,rocks #h ,,ii4 ,! ,lime/ones #ab ,,iii4 ,! ,s&/ones #ef ,,iv4 ,clays1 ,%ales1 & ,slates #gh ,v4 ,igne\s ,rocks #ajc ,,vi4 ,metamorphic ,rocks #adc ,ref]5ces #afb ,table ( ,/ratigraphical ,sy/ems #ahi ,index #agj ,,li/ ,,( ,,illu/rations ,,fig4 ,,page #a ,surface ( ,lime/one plateau1 ,causse du ,l>zac1 ,aveyron #de #b ,rav9e 9 ,lime/one1 ,caon ( ! ,d\rbie1 ,aveyron #dg #c ,wat]worn cliff ( ,lime/one1 ,mill]sdale #di #d ,lime/one c\ntry dissect$ by rav9es1 ,h]cegov9a #ea #e ,s& develop+ f ,s&/one1 ,cape ( ,good ,hope #ei #f ,silice\s ,conglom]ate1 ,co4 ,wat]=d #ge #g ,qu>tzite ,cone1 ,croagh ,patrick #gg #h ,%r9kage-cracks 9 ,clay1 ,spitsb]g5 #ha #i ,l&slide ( ,lime/one ov] ,%ale1 ,drme #ic #aj ,wea!r+ ( ,%ale1 ,isre #ie #aa ,b\ld]-clay1 ,cri*1 ,d]by%ire 7,phot4 ,h4 ,a4 ,bemrose7 #ig #ab ,nord5skild ,glaci]1 ,spitsb]g5 #ii #ac ,sef/rm ,glaci]1 ,spitsb]g5 #aja #ad ,a%-lay] ( #aijf on ,vesuvius #aaa #ae ,puy de la ,va*e1 ,puy-de-,dme #aac #af ,granite invad+ ,mica-s*i/1 ,cape ,t[n #aba #ag ,wea!r+ granite1 ,lundy ,isl& #aci #ah ,granite wea!r+ "u tropical conditions1 ,matopo ,hills #ada #ai ,composite ,gneiss1 ,co4 ,donegal #aec #bj ,composite ,gneiss1 ngn1 ,sw$5 #aee 7,figs4 #aa & #ag are reproduc$ f ! ,cambridge ,c\nty ,geographies ( ,d]by%ire & ,devon%ire respectively2 ! re/ ( ! illu/rations are f photographs by ! au?or47 ,,*apt] ,i ,,on ,,rocks ,,9 ,,g5]al ,! description ( rocks has fall5 v mu* into ! h&s ( lov]s ( analysis & classification1 & att5tion has be5 div]t$1 ev5 among geologi/s1 f _! fundam5tal importance z p>ts ( ! e>?'s cru/4 ,! geograph] or ! g5]al travell] may (t5 wi% = clos] acqua9tance ) ! units t build up ! sc5]y ar\nd him4 ,! *>act]s ( rocks aga9 & aga9 control ! features ( ! l&scape4 ,:5 /udi$ m ne>ly1 ^! same *>act]s imply conditions ( deposition or solidification1 & lead ! m9d back to /ill old] l&scapes1 & to ! meet+ ( oceans & cont95ts on long-=gott5 %ores4 ,petrology1 inde$1 involves ! und]/&+ ( h[ rocks come to be :]e we f9d !m :5 we try2 b ! classification ( h&-specim5s 0 f ! fir/ easi] ?an field-inve/igation1 & 9 lat] times ! sci5ce 0 ?reat5$ ) ! description ( isolat$ microscopic slides4 ,=tunately1 a c]ta9 am\nt ( feel+ = natural hi/ory has be5 import$ aga9 into ! subject1 & evolution>y pr9ciples & sequ5ces h be5 discuss$4 ,exp]im5tal "w1 moreov]1 has be5 br\ght to be> on ! "q ( ! orig9s ( rocks1 ) m success ?an might h be5 expect$1 s9ce x is v difficult to realise 9 a laboratory1 or ev5 9 ! m9d1 ! conditions t prevail 9 ! l[] p>ts ( ! e>?'s cru/4 ,rocks1 we h to rememb]1 are 9 !mselves consid]able masses1 & h relations ) o!rs f> away4 ,! co>s5ess ( a s&/one at "o po9t1 or ev5 ov] squ>e miles ( c\ntry1 implies ! deposition ( f9] mat]ial some:]e else4 ,! lava-fl[ implies ! exi/5ce ( my/]i\s cauldrons 9 ! cru/4 ,x is1 h[ev]1 =tunate t ! prim>y classification ( rocks 0 promulgat$ )\t reg>d = !ories ( rock-orig9s4 ,! "w 0 done by m5 :o 7 ma/]s & pione]s 9 m9]alogy4 ,at a "t :5 a p[]ful s*ool reg>d$ basalt z ( s$im5t>y orig91 & :5 granite 0 g5]ally believ$ to be ! mo/ anci5t compon5t ( ! cru/1 rock-masses 7 tak5 9 h& z aggregates ( c]ta9 m9]als1 & 7 r$uc$ to an ord]ly s*eme = arrangem5t 9 ! cab9ets ( ! curi\s4 ,any sy/em bas$ on ideal relation%ips w\ld h be5 fatal at t "t to petrology z a sci5ce4 ,alex&re ,brongni>t1 9 #ahac1 ?us saw objections to ! classification ( rocks t _h be5 propos$ by ,w]n]4 ,9 8 ,essai d'une classification m9ralogique des ,ro*es mlanges1 he %[$ ! impossibility ( det]m9+ ! age ( a rock 9 relation to o!rs be=e assign+ to x a "n1 & ! absurdity ( sep>at+ simil> rocks on acc\nt ( diff]5ces 9 _! geological age4 ,brongni>t 0 ?us =c$ to rely1 fir/ly1 ^u ! preval5ce ( c]ta9 m9]al con/itu5ts1 &1 secondly1 on ! /ructure ( ! mass4 ,he develop$ ?is s*eme 9 #ahbg1 9 8 ,classification et c>actres m9ralogiques des ,ro*es homognes et htrognes2 b x is cle> t1 ev5 9 su* a sy/em1 consid]ations ( natural hi/ory & ( orig9 w ultimately pr$om9ate4 ,brongni>t 0 mu* influ5c$ by ,k>l von ,leonh>d's ,*>akt]i/ik d] ,fels>t51 publi%$ 9 #ahbc1 & ^! two au?ors h be5 reg>d$ z ! f\nd]s ( petrography4 ,! difficulty ( di/+ui%+ betwe5 rocks laid d[n z true s$im5ts on ! e>?'s surface & ^? t h consolidat$ f a /ate ( fusion has be5 v l>gely remov$4 ,! assi/ance ( ! microscope c n[ be call$ on to elucidate ! m9ute /ructure ( f9e-gra9$ masses1 :i* appe>$ homog5e\s to e>li] work]s4 ,! pione] 9 microscopic me?ods 0 ,pi]re ,l\is ,anto9e ,cordi]1 :o knew rocks z a travell] kn[s !m 9 ! field4 ,9 #agih1 z a "y man ( tw5ty-"o1 he _h gone to ,egypt ) ! fam\s exp$ition "u ,g5]al ,bonap>te4 ,dodat de ,dolomieu _h *>ge ( ! geological obs]vations1 & ,cordi] w5t ?r\gh ! h>d%ips ( ! campaign z 8 assi/ant4 ,:5 ,bonap>te ab&on$ ! army & )drew to ,p>is1 ,cordi] might well h be5 lo/ to ,europe4 ,h[ev]1 he successfully br\ght home ! k acquir$ 9 ! field1 & set himself1 9 ^? agitat+ ye>s1 to solve ! problem ( ! compact gr\ndwork ( igne\s rocks4 ,he argu$ t ?is gr\ndwork probably consi/$ ( m9]als1 & t ^! m9]als 7 probably simil> to ^? occurr+ z visible con/itu5ts ( ! mass4 ,he exam9$ ! p[d] ( ^! l>g] cry/als "u ! microscope1 & made himself famili> ) _! aspect 9 a fractur$ =m4 ,he !n p[d]$ ! compact mat]ial ( 8 rocks1 wa%$ away ! du/1 & 0 able to recognise 9 ! co>s] residue ! m9]als t he _h previ\sly /udi$4 ,he us$ ! magnet to extract ! iron ore2 he det]m9$ ! fusibility ( ! p>ticles ) ! bl[pipe2 & he ev5 discov]$ 9 volcanic lavas a residual glass associat$ ) ! cry/all9e mat]ial#a4 ,to ?is day1 :5 a p>ticul> m9]al has to be det]m9$ 9 a rock1 x is (t5 be/ to foll[ ,cordi]'s me?od1 & to extract ! actual cry/als1 h[ev] small4 ,v>i\s modes ( sep>ation1 especially ^? involv+ ! use ( d5se liquids1 h be5 devis$ s9ce ,cordi]'s "t1 & ! specific gravity ( a s+le cry/al c n[ be det]m9$1 al?\gh x may be s small z to require look+ = 9 ! d5se liquid ) a l5s#b4 ,betwe5 #ahcf & #ahch1 ,*ri/ian ,gottfri$ ,ehr5b]g1 ,pr(essor ( ,m$ic9e at ,b]l91 made an imm5se /ep =w>d 9 ! /udy ( rocks4 ,be+ ke5ly int]e/$ 9 microscopic =ms ( life1 he wi%$ to det]m9e _! importance z con/itu5ts ( rocks4 ,us+ a microscope magnify+ #cjj diamet]s1 he %[$ ! pres5ce ( organisms 9 fl9t & lime/one1 & f\nd 9 #ahch t a ?9 slice ( *alk coat$ ov] ) ,canada balsam became practically transp>5t4 ,9 8 ,mikrogeologie1 publi%$ 9 #ahed1 he gives draw+s ( ?9 sections ( sev]al fl9ts1 se5 by transmitt$ light1 :i* are ?us rock-sections 9 ! mod]n petrological s5se4 ,8 me?od c\ld n h be5 g5]ally kn[n until 8 book appe>$ 9 #ahed4 ,mean:ile1 ,h5ry ,clifton ,sorby1 ab\t #ahde1 f\nd ! naturali/ ,w4 ,c4 ,williamson mak+ ?9 sections ( fossil plants & bones4 ,he promptly p]ceiv$ ! importance ( ! me?od z appli$ to rocks 9 g5]al1 & introduc$ x to ! ,geological ,society ( ,london 9 #ahej1 9 a pap] on ! ,calc>e\s ,grit ( ,sc>bor\gh4 ,sev5 ye>s lat]1 he read 8 memorable pap] on ,! ,microscopical ,/ructure ( ,cry/als#c1 9 :i* he made use ( slices ( granite & ( ,vesuvian & o!r lavas4 ,f]d9& von ,zirkel met ,sorby by *ance at ,bonn 9 #ahfb1 &1 le>n+ 8 me?ods1 proce$$ to sy/ematise ! exam9ation ( rock-specim5s ) ! microscope4 ,su* /udies1 rapidly appreciat$ by ,mi*el ,lvy1 ,ros5bus*1 ,judd1 & o!rs1 naturally l$ to advances ( ! fir/ importance 9 petrology4 ,!y enabl$ work]s to asc]ta9 ! relations ( ! rock-con/itu5ts "o to ano!r1 & ! ord] ( consolidation ( m9]als f an igne\s magma4 ,! broad division ( rocks into ^? ( s$im5t>y & ^? ( igne\s orig9 has be5 fur!r emphasis$4 ,! rocks /yl$ metamorphic /ill af=d ! greate/ difficulty1 ev5 aft] prolong$ enquiry 9 ! field4 ,see+ t "s rocks are m]ely massive m9]als1 t is1 l>ge masses =m$ ( "o m9]al species1 :ile o!rs consi/ ( cry/als or fragm5ts ( a v>iety ( m9]als1 x may be well to rem9d ourselves ( ! di/9ction betwe5 m9]als & rocks4 ,we may def9e a m9]al z a natural sub/ance =m$ by inorganic action2 its *emical composition is con/ant2 "u fav\rable circum/ances1 x assumes a *>act]i/ic cry/all9e =m4 ,l all def9itions ( natural objects1 ! above requires "s qualification4 ,9 _m cases ! *emical composition ( a m9]al v>ies by a well-def9$ s]ies ( atomic replacem5ts1 & we _c feel call$ ^u to e/abli% a new species = e /ep away f ! rigid type4 ,sodium ?us replaces potassium to "s ext5t 9 or?oclase felsp>4 ,! cry/all9e =m1 aga91 may n be specifically *>act]i/ic1 z1 = in/ance1 9 ! memb]s ( ! g>net s]ies1 :i* cry/allise 9 ! cubic sy/em4 ,! homog5eity ( molecul> /ructure ?r\gh\t ! individual may be reg>d$ z ! mo/ ess5tial feature ( :at we /yle a m9]al species2 t is to say1 ! molecules conta9 ! same elem5ts 9 ! same proportions1 & are arrang$ on ! same physical plan4 ,a rock1 on ! o!r h&1 is a m]e aggregate ( m9]al p>ticles1 or ( molecules t1 "u prop] conditions1 w\ld gr\p !mselves to =m m9]al species4 ,x may consi/ entirely ( granules or cry/als ( "o species2 b ! /ructures 9 ^! h no common ori5tation1 z !y w\ld h 9 a s+le l>ge cont9u\s cry/al4 ,! rock itself has no cry/all9e =m1 & any /ructures t simulate su* =ms w be f\nd on measurem5t to h none ( ! regul>ity t *>act]ises g5u9e cry/als4 ,a rock1 moreov]1 =m$ ( sev]al m9]al species 9 association w by no means possess a con/ant *emical composition1 & ! v>iations f po9t to po9t =m a feature ( especial int]e/ 9 ! /udy ( igne\s masses1 ( s$im5ts deposit$ on a %ore1 or ( alluvium 9 a valley /ret*+ f> betwe5 ! hills4 ,9 ! pages t foll[ we hope1 !n1 to be> 9 m9d ! relations ( rocks to ! e>? & to ourselves4 ,l ! anci5t ,romans1 we build our cities ) huge blocks & slabs br\ght f cry/all9e masses ov]sea4 ,we n[ tunnel1 = our comm]cial highways1 ?r\gh ! complex cores ( m\nta9-*a9s4 ,ev]y:]e rocks are our f\ndations1 ?r\gh\t our travels or 9 our settl$ homes4 ,!y rise z ob/acles aga9/ u1 or !y spread be=e u fields ( f]tile soil4 ,"s k ( !m is "p ( ! g5]al body ( culture t makes u1 9 ! be/ s5se1 citiz5s ( ! _w4 ,,li/ ,,( ,,! ,,common ,,m9]als ,,t ,,=m ,,rocks ,act9olite4 ,see ,amphiboles4 ,albite4 ,see ,felsp>s4 ,amphiboles4 ,a s]ies ( silicates ) ! g5]al =mula ,r,si,o#c1 :]e ,r is magnesium1 iron or calcium2 9 _m1 su* z ! common species ,hornbl5de1 molecules occur 9 addition 9 :i* alum9ium & triad iron are introduc$4 ,hornbl5de ?us consi/s ( m 7,mg1 ,fe1 ,ca7 ,si,o#c4 n 7,mg1 ,fe7 7,al1 ,fe7#b ,si,o#f4 ,act9olite is a non-alum9\s amphibole occurr+ 9 ne$le-l prisms4 ,! amphiboles cry/allise 9 prisms hav+ angles ( ab\t #ef & #abd4 ,see ,pyrox5es4 ,anatase4 ,see ,rutile4 ,&alusite4 ,alum9ium silicate1 ,al#b,si,o#e1 cry/allis+ 9 ! rhombic sy/em4 ,sillimanite consi/s also ( ,al#b,si,o#e & is rhombic1 b cry/allises ) diff]5t fundam5tal angles4 ,anor?ite4 ,see ,felsp>s4 ,apatite4 ,calcium phosphate1 ) fluor9e1 or sometimes *lor9e1 7,ca,f7,ca#d7,,po#d7c #c;,ca#c7,,po#d7b4 ,ca,f#b4 ,aragonite4 ,calcium c>bonate1 ,ca,c,o#c1 cry/allis+ 9 ! rhombic sy/em1 ) a specific gravity ( #bic4 ,see ,calcite4 ,augite4 ,see ,pyrox5es4 ,biotite4 ,see ,micas4 ,calcite4 ,calcium c>bonate1 ,ca,c,o#c1 cry/allis+ 9 ! trigonal sy/em1 ) a specific gravity ( #bgb4 ,see ,aragonite4 ,*alc$ony4 ,cry/all9e silica1 ,si,o#b1 9 fibr\s & (t5 mammillat$ =ms4 ,fl9t or ,*]t is a concretion>y =m1 9 :i* "s int]/itial opal may be pres5t4 ,*]t4 ,see ,*alc$ony4 ,*lorites4 ,hydr\s alum9ium magnesium iron silicates1 resembl+ gre5 micas1 b s(t] & ) non-ela/ic plates4 ,*romite4 ,iron *romium oxide1 ,fe,cr#b,o#d4 ,magnesium may replace "p ( ! dyad iron1 & alum9ium & triad iron "s ( ! *romium4 ,diallage4 ,an alt]$ augite ) a %imm]y submetallic lu/re4 ,diopside4 ,see ,pyrox5es4 ,dolomite4 ,magnesium calcium c>bonate1 ,mg,ca7,,co#c7b4 ,en/atite4 ,see ,pyrox5es4 ,epidote4 ,calcium alum9ium iron silicate1 ,ca#b7;,al,o,h77,al1 ,fe7#b7,si,o#d7c4 ,felsp>s4 ,a s]ies ( silicates ( alum9ium ) potassium or sodium or calcium1 or all ( ^!4 ,or?oclase1 ,k,al,si#c,o#h1 & ! correspond+ sodium =m1 ,albite1 ,na,al,si#c,o#h1 lie at "o end ( ! s]ies1 & ! calcium felsp> ,anor?ite1 ,ca,al#b7,si,o#d7b1 at ! o!r4 ,:ile ,or?oclase cry/allises 9 ! monocl9ic sy/em1 a tricl9ic =m1 ,microcl9e1 ) ! same composition1 is also common4 ,all ! o!r felsp>s are tricl9ic1 &1 ) microcl9e1 are (t5 /yl$ plagioclases4 ,! pr9cipal felsp>s betwe5 ,albite & ,anor?ite are ,oligoclase1 ! soda-lime felsp>1 & ,labradorite1 ! lime-soda felsp>4 ,fl9t4 ,see ,*alc$ony4 ,g>nets4 ,a s]ies ( silicates ) ! g5]al composition ( ,r#c,r#b7,si,o#c7d1 ,r be+ ,ca1 ,fe1 or ,mn1 & ,r be+ ,al or ,fe4 ,! common r$ g>net 9 mica-s*i/s is ,alm&9e1 ,fe#c;,al#b7,si,o#c7d1 :ile t 9 alt]$ lime/ones is ,grossul>ite1 ,ca#c;,al#b7,si,o#c7d4 ,glauconite4 ,a hydr\s iron potassium silicate1 ) "s alum9ium1 magnesium1 & calcium1 =m$ 9 m>9e deposits4 ,gypsum4 ,hydr\s calcium sulphate1 ,ca,s,o#d #b ,h#b,o4 ,hornbl5de4 ,see ,amphiboles4 ,hyp]/h5e4 ,see ,pyrox5es4 ,ilm5ite4 ,titanium iron oxide1 m ,fe,ti,o#c n ,fe#b,o#c4 ,iron ,pyrites4 ,iron disulphide1 ,fe,s#b4 ,a cubic species1 ,pyrite1 & a less common rhombic species1 ,m>casite1 occur4 ,kaol94 ,hydr\s alum9ium silicate1 ,h#d;,al#b,si#b,o#i4 ,kyanite4 ,alum9ium silicate1 ,al#b,si,o#e1 cry/allis$ 9 ! tricl9ic sy/em4 ,see ,&alusite4 ,labradorite4 ,see ,felsp>s4 ,leucite4 ,potassium alum9ium silicate1 ,k,al7,si,o#c7b4 ,limonite4 ,hydr\s iron oxide4 ,h#f;,fe#d,o#i4 ,magnetite4 ,magnetic iron oxide1 ,fe#c,o#d4 ,m>casite4 ,see ,iron ,pyrites4 ,micas4 ,a s]ies ( alum9ium silicates1 ) potassium1 magnesium1 or iron1 or all ( ^!4 ,li?ium & sodium sometimes occur4 ,! two m>k$ types are ,muscovite1 ri* 9 alum9ium & potassium1 ! common alkali mica1 ,h#b,k,al#c7,si,o#d7c1 ) a silv]y aspect1 & ,biotite1 ! common d>k f]romagnesian mica1 7,h1 ,k7#b7,mg1 ,fe7#b7;,al1 ,fe7#b7,si,o#d7c4 ,microcl9e4 ,see ,felsp>s4 ,muscovite4 ,see ,micas4 ,nephel9e4 ,sodium alum9ium silicate1 ) "s potassium1 ! pure sodium type be+ ,na,al,si,o#d2 ! types ) potassium conta9 slightly m silica4 ,oligoclase4 ,see ,felsp>s4 ,oliv9e4 ,magnesium iron silicate1 7,mg1 ,fe7#b,si,o#d4 ,opal4 ,uncry/allis$ silica1 ,si,o#b1 ) "s wat]4 ,or?oclase4 ,see ,felsp>s4 ,pyrite4 ,see ,iron ,pyrites4 ,pyrox5es4 ,a s]ies ( silicates correspond+ 9 composition to ! ,amphiboles1 b cry/allis+ 9 prisms :i* h angles ( ab\t #hg & #ic4 ,on ! :ole1 ! pyrox5es are ri*] 9 calcium ?an ! amphiboles4 ,! =mula ( ,wolla/onite is ,ca,si,o#c4 ,diopside consi/s ( ,ca7,mg1 ,fe77,si,o#c7b4 ,augite1 ! commone/ =m1 is alum9\s1 correspond+ to ,hornbl5de among ! amphiboles2 b ! *ange f ,augite into ,hornbl5de1 :i* (t5 occurs1 may imply a loss ( calcium4 ,en/atite & ,hyp]/h5e are species cry/allis+ 9 ! rhombic sy/em2 ! =m] consi/s ( ,mg,si,o#c1 :ile 9 ,hyp]/h5e iron replaces "s ( ! magnesium4 ,qu>tz4 ,silica1 ,si,o#b1 cry/allis$ 9 ! trigonal sy/em4 ,rock-,salt4 ,sodium *loride1 ,na,cl4 ,rutile4 ,titanium dioxide1 ,ti,o#b1 cry/allis$ 9 ! tetragonal sy/em4 ,anatase has ! same composition1 & is tetragonal1 b has diff]5t fundam5tal angles4 ,s]p5t9e4 ,hydr\s magnesium iron silicate1 ,h#d7,mg1 ,fe7#c,si#b,o#i4 ,sid]ite4 ,iron c>bonate1 ,fe,c,o#c4 ,sillimanite4 ,see ,&alusite4 ,talc4 ,hydr\s magnesium silicate1 ,h#b,mg#c7,si,o#c7d4 ,t\rmal9e4 ,a borosilicate ( alum9ium ) v>i\s o!r elem5ts1 ,r#i;,al#c7;,,boh7#b,si#d,o#ai4 ,r repres5ts ,h1 ,na1 ,al1 ,mg1 ,fe4 ,tridymite4 ,silica1 ,si,o#b1 cry/allis$ 9 d\bly refract+ six-sid$ plates4 ,its specific gravity is #bc1 t ( ,qu>tz be+ #bfe4 ,wolla/onite4 ,see ,pyrox5es4 ,zeolites4 ,a s]ies ( hydr\s alum9ium silicates1 ) potassium1 sodium1 calcium1 & sometimes b>ium4 ,zircon4 ,zirconium silicate1 ,zr,si,o#d4 ,,*apt] ,,ii ,,! ,,lime/ones ,,introduction ,! t]m ,lime/one cov]s1 by common cons5t1 rocks consi/+ ma9ly ( calcium c>bonate4 ,dolomite 7prop]ly ,dolomite-rock71 9 :i* half or ne>ly half ! molecules consi/ ( magnesium c>bonate1 is1 h[ev]1 g5]ally includ$4 ,! conv5i5ce ( lime/ones z build+ mat]ials has giv5 !m a _w-wide int]e/4 ,_! /ratifi$ & jo9t$ /ructure appeal$ to ! e>ly ,egyptian ar*itect1 :5 he s\ght blocks = 8 pyramids4 ,! ease ) :i* lime/ones c\ld be c>v$1 comb9$ ) a reasonable resi/ance to decay1 gave !m a pre-em95ce ) ! design]s ( our ri* ca!drals4 ,! ,romans f\nd 9 ! /a9$ & alt]$ v>ieties col\r-s*emes = basilicas & ba?s1 & _! luxuri\s ta/e 9 lime/one has be5 inh]it$ by ! mod]n build]s ( hotels4 ,! rock suff]s1 h[ev]1 f its solubility 9 wat] conta9+ ev5 a mild acid4 ,9 ! gases dissolv$ by ra9-wat] f ! atmosph]e1 c>bon dioxide assumes a f> l>g] proportion ?an t :i* x possesses 9 ! air itself4 ,! surface ( lime/one slabs becomes 9 consequ5ce pitt$ & corrod$ by e ra9 t falls4 ,! sulphuric acid 9 ! air ( mod]n coal-consum+ cities is1 h[ev]1 /ill m deadly 9 its action4 ,j4 ,a4 ,h[e1 9 8 rec5t "w on build+ /ones1 is ( op9ion t lime/one is unsuitable = t[ns4 ,lime/ones may broadly be recognis$ by _! solubility 9 cold dilute acids1 ) brisk evolution ( c>bon dioxide4 ,dolomitic v>ieties require hot acid4 ,lime/ones divide !mselves into types produc$ by *emical precipitation & ^? due to ! accumulation ( ! h>d p>ts ( organisms2 b 9 _m ( ! latt] types *emical precipitation also plays a "p4 ,organic action1 moreov]1 frequ5tly promotes ! deposition ( ! *emical types4 ,detrital lime/ones1 t is1 lime/ones =m$ f ! debris ( old] ones1 are comp>atively unimportant4 ,!y occur 9 c]ta9 zones ( ! ,*alk & ( ! ,c>bonif]\s ,lime/one 9 our isl&s1 & record ! break+ up 9 %all[ wat] ( b$s t _h already become consolidat$4 ,! ,mioc5e ,nagelfluh conglom]ates ( ! nor? side ( ! ,swiss ,alps are (t5 =m$ ( pebbles ( ! f> old] ,mesozoic lime/ones4 ,simil> conglom]ates1 cem5t$ by calcium c>bonate1 are n[ be+ =m$ 9 ! riv]-b$s ( ! lime/one k>/l& ( ,h]cegov9a4 ,lime/one1 h[ev]1 z a rule goes to pieces be=e ! buffet+s su/a9$ by mix$ rocks on a %ore4 ,ev5 if x survives = a "t 9 gravels1 p]colat+ wat]s ultimately dissolve x1 & only a por\s skeleton1 =m$ ( its impurities1 rema9s4 ,,lime/ones ,,deposit$ ,,f ,,solution ,?\gh calcium c>bonate is f> less soluble ?an calcium sulphate1 l>ge quantities are c>ri$ invisibly1 ow+ to ! pres5ce ( c>bon dioxide1 9 riv] wat]s1 & ?us accumulate 9 inl& seas t h no outlet except by evaporation4 ,"h ,calc>e\s ,tufa may be deposit$ z a cru/ ^u ! %ores & on ! gr[+ islets1 z ! wat] %r9ks away1 & be=e ! m soluble gypsum & rock-salt c sep>ate out4 ,hot spr+s ( volcanic orig91 l ! ,sprudel ( ,k>lsbad 9 ,bohemia1 may deposit calcium c>bonate z ! wat] cools & is reliev$ f pressure4 ,at ,k>lsbad1 little gra9s ( granite1 or ( ! m9]als ( granite1 s]ve z c5tres1 & encru/+ lay]s are =m$ r\nd !m1 until pea-l bodies are produc$4 ,^! become cem5t$ toge!r1 giv+ rise to ! well-kn[n fre%wat] pisolitic lime/one or roe/one4 ,on ! %ores ( ! ,great ,salt ,lake ( ,utah1 calc>e\s tufa occurs also 9 ! =m ( gra9s resembl+ little eggs4 ,^! are ! oolitic gra9s t 7 fir/ kn[n z con/itu5ts ( fossil lime/ones4 ,! calcium c>bonate ( oolitic gra9s at ,k>lsbad1 f ! ,great ,salt ,lake1 & f ! sea1 is deposit$ 9 a =m t gives ! reaction ( aragonite :5 boil$ 9 cobalt nitrate4 ,a4 ,lacroix1 h[ev]1 f9ds t ! mat]ial at ,k>lsbad has a specific gravity l[] ev5 ?an t ( calcite1 & t its d\ble refraction is also di/9ctly weak]4 ,he has call$ ?is =m ( calcium c>bonate ktypeite4 ,trav]t9e is a tufa laid d[n on twigs & o!r vegetation1 :]e spr+s em]ge lad5 ) calcium c>bonate4 ,9 a massive =m1 x builds tufa-bas9s1 z 9 ! ,mammo? ,hot ,spr+s ( ! ,yell[/one ,p>k4 ,bo? "h & at ,k>lsbad1 x appe>s t vegetation ( humble type1 multiply+ "u w>m conditions1 mat]ially assi/s ! deposit by )draw+ c>bon dioxide f ! wat]4 ,! un/able calcium bic>bonate is ?us conv]t$ into ! c>bonate1 :i* is ?r[n d[n z a quickly increas+ cru/4 ,among ! lime/one regions ( ! ,d9>ic ,alps1 calc>e\s tufas or trav]t9es1 laid d[n by ord9>y /reams1 =m massive b$s t t5d to *oke ! holl[s ( ! hills4 ,! bas9 ( ,jajce 9 ,bosnia is ?us p>tially fill$ up1 & ! t[n is built on mat]ials br\ght 9 solution f ! m\nta9s4 ,! mod]n wat]s are /ill add+ to ?is deposit1 & ,fr4 ,katz]#d has po9t$ out t ! falls ( ! ,pliva are prev5t$ f cutt+ _! way d[n to ! level ( ! ,vrbas rav9e1 into :i* !y plunge1 by ! mass ( tufa :i* !y build up 9 _! own c\rse4 ,ano!r type ( lime/one deposit$ f solution is ( consid]able int]e/ 9 arid l&s1 or l&s ) only a seasonal ra9fall4 ,:]e evaporation goes on /eadily at ! surface1 :ile wat] is br\ght up by capill>y action f bel[1 calcium c>bonate may =m a cem5t to ! soil1 or to ! crumbl+ rock ne> ! surface1 & a solid calc-tufa may arise by cont9u$ transf]5ce ( matt] 9 solution f l[] levels4 ,9 ! ,cape ( ,good ,hope su* =mations are conspicu\s#e4 ,9 a c>eful s]ies ( exp]im5ts1 ,g4 ,l9ck#f %[$ 9 #aijc t sea-wat] at #ag ,c4 c only hold #jaia p] c5t4 ( calcium c>bonate 9 solution4 ,?\gh ?is quantity is n realis$ 9 ! op5 ocean1 yet ne> %ores riv]s may br+ d[n an excess4 ,! ,?ames1 ?\gh fl[+ = a long di/ance ov] a lime/one area1 conta9s only #jaaf p] c5t4 ( calcium c>bonate2 b spr+s trav]s+ lime/one (t5 c>ry #jc p] c5t41 or t5 times z mu* z t f\nd 9 ord9>y seas4 ,h5ce a precipitation ( calcium c>bonate f ! bic>bonate /ate may take place n f> f l&4 ,! m9]al deposit$ is calcite 9 temp]ate climates & aragonite "u w>m tropical conditions4 ,t su* a precipitation actually occurs is prov$ by ! massive grey lime/ones1 conta9+ mod]n %ells1 :i* h be5 record$ = our isl&s f ! sea-floor (f ! ,isle ( ,man & (f ! coa/ ( ,mayo4 ,9 ! case ( ! ,iri% ,*annel1 ! excess ( calcium c>bonate may be suppli$ by spr+s ris+ ?r\gh ! glacial gravels1 :i* conta9 abundant pebbles ( lime/one4 ,ammonium c>bonate1 aga91 d]iv$ f ! decay ( organisms1 or sodium c>bonate1 w precipitate calcium c>bonate z aragonite f ! calcium sulphate & *loride1 b n f ! calcium bic>bonate1 ( salt wat]4 ,films ( aragonite are at pres5t accumulat+ by ?is process on ! floor ( ! ,black ,sea1 & m>9e oolitic gra9s1 also consi/+ ( aragonite1 are produc$ by ! same reaction4 ,9 ! case ( oolitic gra9s1 deposition is no d\bt help$ by evaporation1 s9ce !y seem to arise 9 %all[ wat]s4 ,! ,oolitic ,lime/ones t h prov$ s admirable z build+ /ones1 :e!r f ! qu>ries ( ,ca5 or ,portl&1 are cem5t$ repres5tatives ( ! loose deposits =m$ 9 mod]n tropical seas4 ,de la ,be*e long ago comp>$ _! gra9s ) ^? f ,we/ ,indian coral-reefs4 ,^! small egg-l bodies develop r\nd fragm5ts ( =am9if]al & o!r %ells1 r\nd ! ossicles ( e*9od]ms1 & r\nd brok5 bits ( coral4 ,at fir/ !y h ! g5]al =m ( ! nucleus2 b1 z !y are roll$ by ! waves dur+ _! gr[?1 !y become m & m sph]oidal z !y enl>ge4 ,bor+ alg make tubul> passages 9 !m1 & ^! h l$ to ! view t alg ( ?read-l =m actually orig9ate oolitic /ructure4 ,doelt]1 ,l9ck1 & o!rs conclude1 ) mu* reason1 t ! mode ( deposition is inorganic4 ,:5 ! gra9s are unusually l>ge1 !y are (t5 flatt5$ & irregul>1 z 9 ! m>9e ,pisolites or ,pea-grits4 ,= build+ purposes1 ! f9e-gra9$ oolites )\t l>ge fossils are mu* s\ght aft]1 s9ce !y c be trimm$ equally 9 any desir$ direction4 ,be=e leav+ ! "q ( ! inorganic deposition ( lime/one1 we may note t ,r4 ,a4 ,daly#g has sugge/$ t ! pre-,cambrian & e>ly ,cambrian lime/ones 7 entirely products ( *emical precipitation4 ,he believes t ! cont95tal areas 7 at fir/ relatively small1 & t ! abundance ( decay+ s(t-bodi$ organisms on ! sea-floor l$ to a cont9u\s precipitation ( su* calcium c>bonate z 0 available4 ,h5ce ! ocean 0 limeless1 & x 0 only :5 cont95tal l& became m ext5d$ t a suffici5t quantity ( lime salts 0 br\ght 9 by riv]s to c\nt]balance t ?r[n d[n by ammonium c>bonate & sodium c>bonate on ! sea-floor4 ,daly urges t1 on ?is acc\nt1 ! e>li] organisms c\ld n =m calc>e\s %ells or skeletons1 & he also believes t pre-,cambrian & ,cambrian lime/ones1 ev5 :5 unalt]$1 %[ no signs ( hav+ orig9at$ f fragm5tal organic rema9s4 ,l9ck's rese>*es 7p4 #ag7 %[ t lime/ones ?us precipitat$ mu/ h orig9ally consi/$ ( aragonite4 ,,lime/ones ,,=m$ ,,( ,,organic ,,rema9s ,^! lime/ones pres5t an imm5se v>iety1 accord+ to ! nature ( ! orig9at+ organisms1 & ! am\nt ( =eign mat]ial br\ght d[n into ! wat] :]e !y accumulat$4 ,! calc>e\s rema9s ( ,*>a may =m a :ite deposit on ! floors ( fre%wat] lakes4 ,! "p play$ by calc>e\s alg 9 ! =mation ( m>9e lime/ones has long be5 recognis$2 b ! detail$ exploration 9 #aijd ( ! atoll ( ,funafuti 9 ! ,pacific %[$ t ,halim$a may be responsible = a consid]able portion ( an ord9>y coral-reef4 ,li?o?amnium occurs 9 imm5se quantities1 associat$ ) molluscan rema9s1 ne> _m %ores1 & =ms a l>ge "p ( ! mat]ial ( ! rais$ bea*es 9 ,spitsb]g54 ,animal1 n vegetable1 activity1 h[ev]1 is responsible = ! majority ( our lime/ones1 & ! humbl] organisms1 by reason ( _! abundance1 play a prom95t "p 9 rock-=mation4 ,analogies betwe5 ! ,globig]9a-ooze ( deep wat]s & ! gr\ndwork ( ! s(t :ite lime/one kn[n z ,*alk h be5 freely po9t$ out4 ,e>ly 9 ! n9ete5? c5tury1 ,ehr5b]g1 9 a s]ies ( rese>*es ) ! microscope1 prov$ ! organic orig9 ( ! compact gr\nd ( m>9e lime/ones4 ,! occurr5ce ( =am9if]a f ! %ore outw>ds to truly oceanic wat]s provides a f9e-gra9$ calc>e\s mat]ial :i* =ms deposits at v v>i\s dep?s4 ,! miliol9e types1 (t5 ) a surface l t ( glaz$ porcela91 are common 9 ! s&y b$s =m$ ne> a coa/4 ,few rocks are m fasc9at+ "u ! microscope ?an ^? 9 :i* su* types are se5 9 section1 associat$ ) detrital gra9s ( qu>tz1 wa%$ d[n f ! l&1 & p]haps ) bright gre5 gra9s ( ! m>9e m9]al1 glauconite4 ,9 ,irel& :ite *alks occur1 speckl$ ?r\gh\t ) glauconite1 :i* looks d>k 9 ! rock-mass1 b :i* reveals its gre5 t9t :5 /reak$ out by ! hamm]4 ,:5 =m$ /ill f>!r f l&1 pure *alk arises f ! consolidation ( =am9if]al ooze1 & ! probable dep? 9 :i* x accumulat$ mu/ be judg$ f ! nature ( ! associat$ organisms4 ,a :ite lime/one may1 h[ev]1 arise 9 a comp>atively %all[ sea1 :]e ! riv]s br+ d[n little solid matt] f ! l&4 ,a coa/ =m$ ( pure lime/one1 ) cle> /reams fl[+ f a l& ( simil> rock beh9d1 may all[ ( ! developm5t ( pure lime/one on its %ores4 ,x is g5]ally agre$ t ! ,upp] ,*alk ( ! ,briti% ,isles & ( nor!rn ,france 0 laid d[n 9 wat] "o ?\s& fa?oms or m 9 dep?2 yet ! correspond+ :ite lime/one ( nor!rn ,irel& 9 places foll[s rapidly on conglom]atic & glauconitic deposits1 & seems to owe its purity to ! comp>ative abs5ce ( ra9 & riv]s on ! highl& ( cry/all9e rocks :i* /ret*$ we/w>d f its %ore4 ,!re are two epo*s ( ! e>?'s hi/ory 9 :i* =am9if]a 7 rem>kable = _! size z well z _! abundance4 ,! fir/ gave u ! grey ,fusul9a lime/one ( ,upp] ,c>bonif]\s times1 :5 ?is sp9dle-%ap$ %ell spread freely f ! ,unit$ ,/ates ?r\gh ! arctic regions to ! ea/ ( ,asia4 ,! second gave u1 9 ! ,eoc5e p]iod1 ! great b$s =m$ ( ,nummulites & ,orbitoides1 :i* we meet ) 9 ,europe on ! ,lake ( ,?un1 b :i* are f> m important 9 ,l[] ,egypt4 ,! disc-l =ms ( ! nummulites 9 ! :ite lime/one ( ! ,pyramids are famili> to hundr$s ( travell]s1 & =ms are record$ up to f\r & a half in*es across4 ,! =am9if]al orig9 ( _m compact lime/ones c (t5 be appreciat$ on smoo? surfaces ) a pocket-l5s4 ,! old] examples h commonly become /a9$ & d>k5$1 & cry/allisation ( calcite ?r\gh\t ! gr\nd has 9 "p de/roy$ ! orig9al organic /ructures4 ,?is t5d5cy to cry/allise affects ev5 ! l>g] fossils1 & bra*iopods & molluscs h sometimes disappe>$ f our ,c>bonif]\s lime/ones1 )\t ! int]v5tion ( metamorphic heat or pressure4 ,9 mo/ lime/ones old] ?an ! ,eoc5e p]iod1 ! %ells & o!r fossils1 su* z corals1 t 7 orig9ally =m$ ( aragonite h pass$ into ! calcite /ate1 )\t ! de/ruction ( _! *>act]i/ic %apes4 ,%ells1 h[ev]1 h be5 f\nd /ill pres]v$ z aragonite 9 b$s z old z ! ,jurassic p]iod#h4 ,! lamellibran*s1 ! ord9>y bivalves1 came into prom95ce z lime/one-build]s ) ! ,c>bonif]\s p]iod1 & are n[ rivall$ by ! univalve ga/ropods1 :i* display$ no widespread activity until ,eoc5e times4 ,! mo/ massive exi/+ %ell1 h[ev]1 is a lamellibran*1 ! giant ,tridacna ( ,au/ralian seas1 a s+le valve ( :i* may weigh #bej lbs4 ,! cephalopods1 ?\gh ly+ f> ne>] to ! cr[n ( molluscan developm5t1 became important f ! ,silurian ,or?oc]as onw>ds1 & nautiloids ( v>i\s =ms are common fossils 9 ! ,c>bonif]\s lime/one4 ,_! l>ge size attracts att5tion f our pres5t po9t ( view4 ,! cephalopods1 h[ev]1 swell ! bulk ( _m lime/ones1 n by ! ?ickness ( _! %ells1 b ?r\gh _! *amb]$ "*1 :i* has prev5t$ complete infill+ ( ! %ell1 & :i* ?us all[s ( cavities 9 ! mass4 ,?is is notably ! case ) ! ammonites1 :i* contribute s l>gely to ,jurassic lime/ones4 ,cry/all9e calcite has (t5 be5 deposit$ by infiltration on ! septa & on ! inn] lay] ( ! %ell1 ?us r$uc+ ! holl[ spaces4 ,! massive calcite gu>ds ( ! belemnites =m a consid]able "p ( _m lime/ones4 ,ev5 fre%wat] lakes possess molluscan deposits1 produc+ a :ite lime/one ( _! own4 ,:]e /reams fl[ ov] pure pre-exi/+ lime/one1 !re is no alluvial mud to *oke ! bas9s4 ,9 ! h>d lake-wat]s1 ga/ropods su* z ,limna & ,planorbis1 & a few bivalves1 c !n fl\ri% freely1 & a %ell-m>l accumulates at ! bottom1 unmix$ ) s$im5t4 ,lime/one ( ?is type is conspicu\s 9 holl[s 9 ! ,d9>ic ,alps1 :i* 7 once occupi$ by lakes1 & is (t5 f\nd b5ea? peat 9 ! lime/one l[l& ( c5tral ,irel&4 ,9 old] days1 two gr\ps ( organisms1 n[ relatively unimportant1 _h a p[]ful place4 ,! bra*iopods1 includ+ 9 e>ly ,palozoic times an int]e/+ s]ies ( ?9 %ells l>gely compos$ ( calcium phosphate1 7 = long ! pr$om9ant %ell-be>+ organisms4 ,! /\t ,spirif]id & ! well-kn[n ,productus giganteus ( ! ,c>bonif]\s p]iod illu/rate _! dom9ance4 ,! gr\p became mu* re/rict$ 9 v>iety 9 ,jurassic times2 b ev5 !n ,t]ebratula & ,rhyn*onella occurr$ s abundantly t !y n[ fall out ( _m rock-faces l pebbles f a loose conglom]ate4 ,! sea-lilies h simil>ly lo/ _! place z lime/one-build]s1 ?\gh _! ossicles1 notably f _! /ems1 furni% cr9oidal or encr9ital masses f ,silurian to ,c>bonif]\s times4 ,! brok5 portions ( _! /ems1 resembl+ tubes ( tobacco-pipes1 are conspicu\s :5 !y are wea!r$ out on rock-surfaces or reveal$ 9 poli%$ slabs ( m>ble4 ,! fact t ea* jo9t or ossicle1 z is ! univ]sal case 9 ! e*9od]mata1 consi/s ( a s+le cry/al ( calcite causes ! fragm5ts to break ) ! *>act]i/ic cleavage ( t m9]al4 ,! smoo? glanc+ surfaces ?us se5 on fractur$ specim5s readily call att5tion to !m 9 a rock4 ,^? humble colonial organisms1 ! comp\nd corals1 h s special a place z lime/one-=m]s t !y h be5 res]v$ = m detail$ treatm5t4 ,! accumulation ( _! skeletons1 & ! fact t !y may =m l>ge cont9u\s masses by _! v mode ( gr[?1 promotes ! =mation ( solid rock at an unusual rate4 ,von ,ri*?(5 long ago po9t$ out h[ =am9if]a & o!r drift$ mat]ial became caught 9 ! int]/ices ( coral1 produc+ ev5 a /ratifi$ /ructure 9 ! holl[s ( a reef2 & subsequ5t rese>* has %[n ! composite "* ( reefs 9 v>i\s portions ( ! tropic seas4 ,calc>e\s alg z already rem>k$1 & ! massive & (t5 encru/+ skeletons ( hydrozoa1 su* z ,millepora1 are freely associat$ ) ! products ( true corals4 ,*>les ,d>w91 9 8 fam\s !ory ( ! =mation ( atolls & b>ri]-reefs1 %[$ h[1 9 a subsid+ area1 corals might keep pace ) ! d[nw>d movem5t4 ,h5ce reefs might arise ( great v]tical ?ickness1 al?\gh ! polypes !mselves c\ld fl\ri% only 9 ! upp] tw5ty fa?oms or s ( wat]4 ,?is conclusion1 :i* appe>s /rictly logical1 has met ) mu* opposition f ,k>l ,semp]1 ,alex&] ,agassiz1 & ,sir ,john ,murray4 ,murray 9 p>ticul> urges ! importance ( banks ( calc>e\s organisms 9 build+ up plat=ms on :i* corals may ultimately dwell4 ,! ext5sion ( reefs outw>d into deep wat] has be5 attribut$ to ! roll+ d[n ( wave-worn coral debris ov] subm>9e m\nta9-slopes4 ,f ?is po9t ( view1 an app>5tly ?ick atoll may be =m$ z a comp>atively ?9 mass ( lime/one at ! summit ( a volcanic cone t fails to rea* ! sea-level4 ,! oppon5ts ( ! view t ?ick coral-lime/ones are =m$ at ! pres5t day 9 ! ,pacific h be5 unwill+ to accept ! results ev5 ( ! deep bor+ 9 ! atoll ( ,funafuti#i1 :i* p5etrat$ mat]ials l ^? ( ! sup]ficial lay]s ( ! reef to a dep? ( #aaad feet4 ,!y h also refus$ to see 9 ! huge dolomitic rocks ( ,tyrol ! rema9s ( ,triassic reefs f\r ?\s& feet 9 ?ickness4 ,none ! less1 mo/ geologi/s reg>d ! ,funafuti bor+ z a /rong support = ,d>w9's cont5tion4 ,:atev] may be prov$ z to ! orig9 ( ?is or t atoll at ! pres5t day1 x is cle> t ! possibility ( subsid5ce leads u to expect consid]able coral-lime/ones among our anci5t rocks4 ,! same problem arises :]ev] we h a ri* molluscan fauna cont9u\sly repres5t$ 9 two or ?ree ?\s& feet ( lime/one1 or :]e we f9d %ore-deposits ( any k9d accumulat$ to an unusual ?ickness4 ,d>w91 at ! end ( ! fif? *apt] ( 8 "w on ,! /ructure & di/ribution ( ,coral-,reefs1 gives a vivid acc\nt ( ! features t w\ld appe> 9 a section ( an atoll t has gr[n l>ge ?r\gh subsid5ce ( its inorganic floor1 & he emphasises ! occurr5ce ( conglom]ates ( brok5 coral-rock on ! out] zone4 ,! /ratification ( mat]ial by wave-action 9 ?is zone1 & ! horizontal deposition ( f9] mat]ial 9 ! lagoon1 w\ld give to ! dissect$ mass a g5]al s$im5t>y aspect4 ,d>w9 conclud$ t ! r+ ( solid coral1 ! true reef1 might be d5ud$ away dur+ an epo* ( elevation1 & t only /ratifi$ portions might rema94 ,he does n seem to h discuss$ ! contemporane\s deposition ( pelagic mat]ial f =am9if]al & o!r s\rces aga9/ ! out] surface ( ! reef :]eby an int]lock+ ( two facies ( lime/one might arise4 ,^! features1 toge!r ) ^? pr$ict$ by ,d>w91 h be5 recognis$ by von ,ri*?(5 & ,mojsisovics 9 ! ,tyrol dolomites1 & h af=d$ ,au/rian geologi/s good evid5ce t l>ge p>ts ( ^! lime/ones orig9at$ z coral-reefs4 ,fault+1 h[ev]1 has und\bt$ly tak5 place 9 ?is region1 produc+ "h & !re a subsid5ce ( ! lime/one blocks among ! surr\nd+ m normal s$im5ts4 ,ro?pletz1 ,ogilvie ,gordon#aj1 & o!r critics ( von ,ri*?(5's view h se5 9 ?is fault+ ! cause ( ! abrupt *ange f a facies ( massive dolomite to "o ( normal s$im5tation on ! same horizontal level4 ,!y h also urg$ t %ell-banks may accumulate locally s z to simulate reefs by _! contra/ ) _! surr\nd+s1 :ile ! *ange to dolomite has oblit]at$ _! orig9al features 7see p4 #cj74 ,x _c be d5i$1 h[ev]1 t coral-reefs & _! associat$ detrital deposits mu/ ex]cise a v important influ5ce 9 ! =mation ( solid lime/one4 ,ev5 small knots & local gr\ps ( comp\nd corals are se5 9 ord9>y lime/ones to s]ve z a me% 9 :i* o!r organic rema9s h become entrapp$4 ,! ease ) :i* ! aragonite ( _! skeletons becomes silicifi$ causes !m (t5 to /& out on wea!r$ surfaces ) all ! delicacy ( /ructure display$ ^u a mod]n reef4 ,:]e lime/ones & %ales are associat$ toge!r1 a knoll /ructure may be f\nd1 ! lime/one occurr+ 9 masses ( a some:at hemisph]ical =m1 ) ! %ales fitt$ aga9/ & r\nd !m4 ,9 "s cases ?is may be due to ! local di/ribution ( pat*es ( gr[+ coral on ! old sea-floor2 b 9 o!r cases ! /ructure has aris5 f compression & brecciation ( ! /rata1 ! orig9al b$s ( lime/one becom+ brok5 up & ! m yield+ b$s fl[+ r\nd !m4 ,?is /ructure is well se5 on a small scale 9 _m cru%-conglom]ates1 :]e ! lime/one appe>s z knots & eyes1 resembl+ pebbles4 ,yet ne> at h& ! true b$d+ may be trac$1 b&s ( lime/one alt]nat+ ) %ale1 & a few cross-jo9ts indicat+ ! possibility ( a sep>ation ( ! lime/one into blocks4 ,^! blocks become r\nd$ 9 ! g5]al rock-fl[2 b ,g>d9] & ,reynolds#aa sugge/ solution by infilt]+ wat] z an explanation ( c]ta9 rem>kable examples /udi$ by !m4 ,,alt]$ ,,=ms ,,( ,,massive ,,lime/one ,a c]ta9 am\nt ( magnesium c>bonate is pres5t 9 ! skeletons ( "s m>9e organisms4 ,?is has be5 %[n bo? by ,=*amm] & ,wal!r#iaa4 ,a =am9if]1 ,nubecul>ia novorossica1 has be5 f\nd ) #bf p] c5t4 ( magnesium c>bonate1 & a s]pula ) #gfd p] c5t42 alcyon>ian corals conta9 up to #icb p] c5t41 :ile calc>e\s alg1 su* z ,li?o?amnium & ,halim$a1 conta9 ab\t #ab p] c5t4#ab4 ,! magnesium salt is n1 h[ev]1 "h comb9$ ) calcium c>bonate to =m ! m9]al dolomite2 none ! less x is cle> t su* organisms introduce magnesium 9 appreciable quantities into ! con/itution ( m>9e lime/ones4 ,m>9e lime/ones are v commonly dolomitis$4 ,dolomite1 ! jo9t c>bonate1 ,ca,mg7,,co#c7b1 conta9s #edce p] c5t4 ( calcium c>bonate & #defe p] c5t4 ( magnesium c>bonate1 or c>bon dioxide #dgh1 lime #cjd1 & magnesia #bah4 ,its specific gravity is #bhe4 ,! occurr5ce ( dolomite 9 intimate association ) calcite has be5 prov$ by ,e4 ,w4 ,skeats#ac 9 ! case ( mod]n coral-reefs1 & ! second>y deposition ( ! m9]al has be5 made cle>4 ,! skeletons ( ! corals !mselves may n[ consi/ ( dolomite1 :ile calcite has cry/allis$ 9 _! int]/ices1 or rema9s z "p ( ! orig9al infill+ ( mud4 ,! pres5ce ( dolomite 9 reefs has1 ( c\rse1 long be5 kn[n1 hav+ be5 obs]v$ by ,j4 ,d4 ,dana 9 #ahdi1 & x has be5 realis$ t1 by prolong$ alt]ation1 masses ( ,dolomite ,rock become built up#ad4 ,commonly1 ! process produces a ,dolomitic ,lime/one1 9 :i* calcium c>bonate is /ill 9 excess ( ! #ed p] c5t4 :i* is pres5t 9 ! m9]al dolomite4 ,! alt]ation ( ! orig9al lime/one is1 h[ev]1 suffici5tly pr(\nd4 ,! ready cry/allisation ( dolomite z rhomboh$ra de/roys ! organic /ructure1 & traces ( corals or molluscan %ells disappe> f great ?icknesses ( rock4 ,x is unc]ta9 :e!r ! process ( dolomitisation proce$s mo/ rapidly 9 ! evaporat+ wat]s ( ! lagoons1 or1 z ,pfaff believes1 at consid]able dep?s1 :]e ! pressure may rea* #ajj atmosph]es4 ,magnesium c>bonate1 z we %all note lat]1 may be remov$ f dolomite 9 solution "u pressure at a great] rate ?an calcium c>bonate4 ,if ?is occurs 9 sea-wat]1 x w\ld seem to militate aga9/ ! production ( dolomite 9 ! l[] levels ( a reef4 ,! magnesium requir$ = dolomitisation is d]iv$ f ! magnesium sulphate & *loride ( sea-wat]1 calcium be+ remov$ dur+ ! *ange4 ,c4 ,klem5t 9 p>ticul> urges t a conc5trat$ solution ( sodium *loride at #fj ,c4 assi/s ! process 9 ! case ( magnesium sulphate4 ,aragonite1 ! mat]ial ( coral skeletons & ( mo/ molluscan %ells1 is m susceptible ?an calcite4 ,! temp]ature ( ,klem5t's exp]im5ts may be realis$ 9 lagoons or betwe5 tide-m>ks1 & ,doelt] sugge/s t ! elem5t ( "t 9 nature may all[ ! reaction to take place at l[] temp]atures4 ,! intimate /ructure ( mod]n dolomitic lime/one1 z exhibit$ 9 coral-reefs1 satisfies u t _m old] or fossil dolomites 7 =m$ f m>9e calc>e\s deposits :ile ^! 7 /ill accumulat+4 ,9 o!r cases we mu/ admit t ! dolomite has develop$ 9 ! neighb\rhood ( jo9ts aft] ! consolidation ( ! rock4 ,! view t dolomitisation results f ! m]e removal ( calcium1 ! magnesium orig9ally pres5t 9 organic skeletons becom+ ?us m conc5trat$1 is n borne out by rec5t obs]vations4 ,skeats#ae has c>efully comp>$ ! dolomite-rocks ( ,tyrol ) ! mat]ials ( rec5t coral-reefs4 ,9 bo? !re is a /rik+ abs5ce ( detritus ( inorganic orig91 & 8 "w goes f> to %[ t ! mu*-discuss$ ,alp9e dolomites 7 =m$ "u conditions :i* occur 9 ! neighb\rhood ( exi/+ reefs4 ,?is1 h[ev]1 does n solve ! "q z to :e!r we are deal+ 9 ,tyrol ) fossil coral-reefs1 or ) ! calc>e\s type ( ord9>y m>9e s$im5ts1 :i* might und]go ! same k9d ( alt]ation4 ,:ile ,skeats f9ds 9 two dolomites f rec5t reefs #dc p] c5t4 ( magnesium c>bonate1 ! sub/itution seems usually to t]m9ate :5 #dj p] c5t4 has be5 introduc$4 ,9 ,tyrol1 h[ev]1 ! process has gone s f> z to give rise to true dolomites1 ) #defe ( magnesium c>bonate4 ,! dolomites ( ! ,jurassic s]ies 9 nor? ,bav>ia are massive rocks almo/ devoid ( fossils1 trav]s$ by %r9kage cracks1 & associat$ ) ri*ly fossilif]\s /ratifi$ lime/ones4 ,! relations ( ^! two types ( rock are ^? ( coral-reefs to ! b$d$ deposits on _! flanks1 & ! dolomite seems to m]ge horizontally into ! /ratifi$ s]ies4 ,z 9 ,tyrol1 fossils & corals are r>e 9 ! bosses ( dolomite1 b ! /ructural evid5ce is /rongly 9 fav\r ( _! hav+ orig9at$ z /eeply sid$ reefs4 ,! dolomitic facies ( ! ,c>bonif]\s lime/one 9 our isl&s is an example ( ! second type ( orig94 ,! dolomite "h frequ5tly occurs 9 irregul> ve9s & pat*es4 ,! introduction ( iron c>bonate ) ! magnesium salt /a9s ! dolomite br[n on exposure to oxidation1 & its limits are ?us cle>ly se5 9 ! g5]al blue-grey mass4 ,! dolomitisation has evid5tly proce$$ f jo9t-surfaces inw>ds4 ,x is (t5 suffici5tly ?or\gh to oblit]ate all traces ( fossils1 & ! %r9kage accompany+ ! *emical *ange has produc$ num]\s cavities1 9 :i* calcite has subsequ5tly cry/allis$4 ,an expansion takes place :5 aragonite is alt]$ into dolomite1 unless m ( ! calcium c>bonate is remov$ ?an is necess>y to give place to ! magnesium c>bonate introduc$4 ,9 ! *ange f calcite1 ) a d5sity ( #bgb1 to dolomite1 ) a d5sity ( #bhe1 !re is1 on ! o!r h&1 a %r9kage ( #def p] c5t4 ,:]e ! alt]ation1 !n1 takes place :ile ! aragonite organisms /ill rema9 z aragonite1 & n z calcite1 an expansion r ?an a contraction %\ld occur 9 ! sub/ance ( a reef2 b :5 an old lime/one1 9 :i* all ! calcium c>bonate is pres5t z calcite1 becomes dolomitis$1 a consid]able %r9kage w occur1 & rifts & holl[s may rema9 obvi\s4 ,v few dolomites1 except ^? f\nd 9 association ) rock-salt & o!r products ( ! evaporation ( lagoons1 c n[ be attribut$ to direct *emical deposition f ! sea4 ,daly#g has argu$ t ! fir/ ,palozoic & ! pre-,cambrian dolomites 7 =m$ by precipitation1 s9ce ! calcium salts 9 ^? e>ly days 7 completely remov$ f ! sea-wat]4 ,ammonium c>bonate1 ?\gh effective 9 precipitat+ ! calcium salts1 does n act on ^? ( magnesium until ! calcium salts h be5 br\ght d[n4 ,b1 "u ! conditions po/ulat$ = ! riv]-wat]s t rea*$ ! sea f ! e>lie/ cont95tal l&s1 conditions involv+ ! pres5ce ( only small quantities ( salts ( calcium1 ! decay ( organisms on ! sea-floor might lead to a deposition ( all ! magnesium salts1 foll[+ on ^? ( calcium1 bo? com+ d[n 9 ! =m ( c>bonates4 ,! exp]im5tal "w ( ,pfaff#af %\ld be consid]$ 9 connexion ) ,daly's sugge/ions1 s9ce means are !re indicat$ :]eby basic magnesium c>bonate1 precipitat$ f sea-wat]1 may associate itself ) calcium c>bonate to =m dolomite2 %all[-wat] conditions1 ) conc5tration by evaporation1 are requir$4 ,daly comp>es analyses ( riv]-wat]s n[ runn+ ov] pre-,cambrian rocks ) analyses ( pre-,cambrian lime/ones1 & ! ratio ( ! c>bonates ( magnesium & calcium is %[n to be ! same 9 bo? s]ies4 ,f :at we h said1 x n[ seems probable t ! great majority ( dolomitic lime/ones owe _! magnesium to sub/itution f )\t4 ,direct precipitation ( dolomite has1 h[ev]1 be5 invok$ to acc\nt = sev]al cases ( ,p]mian age1 su* z ! ,magnesian ,lime/one ( ! c\nty ( ,durham4 ,ne> ,sund]l&1 ?is rock is greatly modifi$1 conta9+ ball-l & o!r concretions1 associat$ ) frequ5t cavities4 ,traces ( ! orig9al b$d+ rema91 runn+ ?r\gh ! concretions1 & m>9e fossils are abundant4 ,conybe>e & ,phillips1 s f> back z #ahbb1 /at$ t ! nodules 7 devoid ( magnesia1 ?\gh =m$ 9 a magnesian rock4 ,9 spite ( ?is1 ^! objects long appe>$ z dolomite 9 collections4 ,e4 ,j4 ,g>wood#ag %[$ conclusively t !y result$ f ! conc5tration ( calcium c>bonate 9 a concretion>y =m4 ,! process :]eby a dolomite may ?us rev]t t[>ds ! ord9>y lime/one condition1 ) removal ( magnesium 9 mo/ cases1 has be5 /yl$ d$olomitisation4 ,wat] conta9+ calcium sulphate aft] pass+ ?r\gh a dolomite is f\nd to c>ry magnesium sulphate by a *emical ex*ange4 ,skeats#ah1 moreov]1 po9ts out t1 "u a pressure ( five atmosph]es ! magnesium c>bonate ( dolomite becomes m soluble ?an ! calcium c>bonate 9 fre% wat] conta9+ c>bon dioxide4 ,! ord9>y relations are ?us rev]s$ "u pressure1 & a cause ( d$olomitisation may be indicat$4 ,"u ! influ5ce ( contact-action f igne\s rocks1 dolomite may sep>ate into calcium c>bonate1 magnesium oxide1 & c>bon dioxide4 ,! magnesium oxide takes up wat] & yields ! flaky col\rless m9]al brucite4 ,:]e silica is pres5t1 ei!r z an impurity 9 ! dolomite1 or introduc$ f an invad+ silice\s magma1 magnesium & calcium silicates may be built up#ai4 ,oliv9e ?us arises1 &1 on becom+ hydrat$ & pass+ into s]p5t9e1 /a9s ! rock 9 v>i\s %ades ( gre54 ,! calcium c>bonate cry/allises z a gr\nd ( granul> calcite1 & ! :ole mass becomes a h&some ,ophicalcite1 or s]p5t9\s m>ble4 ,! fam\s rock ( ,connem>a1 us$ 9 poli%$ slabs1 has aris5 ?r\gh contact ) intrusive diorite4 ,dolomitic lime/ones are liable to decay rapidly 9 t[ns1 ow+ to ! =mation ( magnesium sulphate1 :i*1 z %[n above1 is ev5 m soluble 9 wat] ?an is ! accompany+ calcium sulphate4 ,9 ! c\ntry1 ! cry/als ( dolomite resi/ ord9>y wea!r+ by ! c>bon dioxide ( ! ra9-wat] bett] ?an ^? ( calcite2 & ! rock ?us becomes loos5$ ?r\gh ! loss ( "o con/itu5t1 & crumbles into a dolomite s&#bj4 ,compact dolomites1 h[ev]1 h furni%$ "s excell5t build+-/ones = c\ntry use1 s9ce "h ! m resi/+ m9]al =ms ! bulk ( ! rock4 ,! ,phosphatic ,lime/ones are comm]cially ev5 m important4 ,tricalcium or?ophosphate1 d]iv$1 p]haps1 9 ! fir/ in/ance f ! decay ( bones ( fi%es & ! excreta kn[n z coprolites1 t5ds to become aggregat$ 9 c]ta9 lime/ones1 z 9 ! *alk ( ,mons 9 ,belgium & ( ,tapl[ 9 ,buck+ham%ire4 ,! phosphate replaces =am9if]al & o!r %ells1 & frequ5tly =ms int]nal ca/s ( fossils4 ,9 ! latt] case1 x has replac$ ! calc>e\s mud t fir/ occupi$ ! %ells4 ,! obs]vations ( ! ,*all5g] exp$ition %[ t concretion>y calcium phosphate is =m+ among ! calc>e\s & glauconitic oozes ( exi/+ oceans1 nodul> masses collect+1 9 :i* =am9if]al %ells are unit$ & ev5 replac$ by calcium phosphate4 ,:]e deposits ( guano are =m$ by sea-birds on surfaces ( coral lime/one1 z at ,*ri/mas ,isl& to ! s\? ( ,java & at ,sombr]o 9 ! ,w9dw>d ,isl&s1 calcium phosphate becomes wa%$ d[nw>ds & replaces "p ( ! calcium c>bonate ( ! rock4 ,! result+ phosphatic lime/one is qu>ri$ on a comm]cial scale1 & ! v exi/5ce ( ,*ri/mas ,isl& is said to be ?reat5$ by ! en]gy ( excavators4 ,! phosphorites du ,qu]cy1 well kn[n to agriculturi/s 9 ,france1 are accumulations 9 holl[s & fissures ( ,jurassic lime/one1 & are associat$ ) ! bones ( fossil mammals4 ,b 9 ?is & 9 o!r cases !re is mu* d\bt z to :e!r ! phosphate is d]iv$ f ! bones1 or is locally conc5trat$1 ) o!r impurities1 su* z s& & clay1 ?r\gh solution ( ! adjac5t lime/one4 ,! mo/ common sub/ance t replaces calcium c>bonate 9 lime/ones is silica1 9 ! =m ( ,fl9t4 ,! nodules ( ?is mat]ial1 :ite on ! outside & ri*ly black )91 m>k b&s ( /ratification 9 ! ,cretace\s *alk1 & are among ! be/ kn[n mat]ials 9 s\?-ea/ ,engl&4 ,_! fanta/ic =ms h giv5 rise to _m speculations4 ,sometimes1 h[ev]1 :5 fractur$1 !y are cle>ly se5 to include ! rema9s ( fossil sponges4 ,! sponges may be repres5t$ m]ely z holl[ ca/s2 b !re is abundant evid5ce 9 o!r cases t !y belong to g5]a :i* secret$ skeletons ( amorph\s 7non-cry/all9e7 silica dur+ life4 ,! nodul> fl9t has collect$ r\nd ! sponge1 :ile ! sponge itself has (t5 disappe>$4 ,g4 ,j4 ,h9de#ba has %[n h[ readily ! spicules ( silice\s sponges g into solution4 ,ev5 at ! bottom ( exi/+ seas !y become r\nd$ at ! ends1 :ile _! canals become enl>g$4 ,9 "s fossil in/ances1 !y are replac$ by calcite4 ,w4 ,j4 ,sollas#bb1 emphasis+ ?is po9t1 rem>ks t x may be tak5 z an almo/ inv>iable rule t ! replacem5t ( organic silica by calcite is always accompani$ by a subsequ5t deposition ( ! silica 9 "s =m or o!r4 ,?is subsequ5t deposition is frequ5tly at ! exp5se ( calcite 9 "s o!r "p ( ! rock4 ,! solid fl9t is a replacem5t ( ! lime/one 9 :i* x occurs4 ,! pocket-l5s w (t5 %[ traces ( sponge-spicules1 z dull little rods1 9 ! transluc5t sub/ance ( a fl9t4 ,b ! microscope %[s t ! mass ( ! fl9t has ! /ructure ( ! lime/one 9 :i* x lies4 ,! =am9if]a & o!r small /ructural features ( ! orig9al rock are p]fectly pres]v$ 9 *alc$onic 7t is1 m9utely cry/all9e7 silica4 ,l>g] fossils1 su* z ?ick molluscan %ells & ! te/s ( sea-ur*9s1 may escape alt]ation1 :ile ! *alk mud1 ! orig9al ooze1 ) :i* !y are infill$ has become completely silicifi$4 ,?is expla9s ! int]nal m\lds ( fossils 9 br[n oxidis$ fl9t t are f\nd 9 gravel-pits on ! surface ( ! ,*alk1 & also ! tubul> holl[s1 repres5t+ /ems ( cr9oids1 t (t5 occur 9 fl9t f ! ,c>bonif]\s ,lime/one4 ,9 ! latt] case1 ! fossil rema9$ calc>e\s :ile ! gr\nd became silicifi$1 & ! fossil 0 remov$ by subsequ5t solution4 ,:]e great ?icknesses ( /rata1 z may happ5 9 ! ,c>bonif]\s ,lime/one1 h become ?us silicifi$1 x may be presum$ t silice\s skeletons 7 unusually abundant 9 ! mass4 ,b1 z ,l4 ,cayeux#bc obs]ves1 su* skeletons may be 9 "o case entirely remov$1 & 9 ano!r repres5t$ by massive fl9ts2 9 yet ano!r case1 ! silica may rema9 dissem9at$ ?r\gh ! rock4 ,! irregul>ity ( its segregation is %[n by ! gr[? ( fl9ts 9 bran*+ or hook-l =ms1 runn+ f "o b$ to ano!r 9 a lime/one4 ,oolitic lime/ones & ! skeletons ( corals1 bo? hav+ be5 orig9ally made ( aragonite1 are (t5 replac$ by fl9t1 =m+ conclusive in/ances1 appreciable by ! nak$ eye1 ( ! second>y orig9 ( ?is =m ( silica4 ,traces ( diatoms are comp>atively r>e1 ?\gh !y probably contribut$ to ! silicification ( ! fre%wat] ,calcaire de la ,brie ( ! ,p>is bas94 ,radiol>ia1 h[ev]1 h n[ be5 well recognis$ z fl9t-=m]s1 ev5 9 d>k *]ts ( ,silurian age4 ,radiol>ian *]ts h be5 tak5 z an indication t ! b$s 9 :i* !y occur 7 =m$ 9 oceanic dep?s4 ,x is difficult to det]m9e ! /age 9 ! hi/ory ( a rock at :i* silicification has set 94 ,z ,a4 ,jukes-,br[ne#bd rem>ks1 solution ( ! silica skeletons may be accel]at$ by pressure1 i4e4 by ! dep? ( wat] 9 :i* ! b$ accumulat$4 ,yet1 9 comp>ison ) ! calc>e\s %ells ( =am9if]a1 radiol>ian & diatomace\s rema9s are only sl[ly soluble1 & are f\nd 9 ! deepe/ spots rea*$ by s\nd+s4 ,h4 ,b4 ,guppy#be1 on ! o!r h&1 has obs]v$ silicification ( mod]n corals 9 reefs 9 ! ,fijis1 & believes t ! process w5t on dur+ ! elevation ( ! area1 :5 wat]s conta9+ silica became conc5trat$1 & p>ts ( ! mass 7 expos$ to evaporation4 ,! in/ability ( ! non-cry/all9e silice\s skeletons 9 geological "t makes x probable t a rock _c long reta9 !m :5 buri$ among o!r /rata 9 ! e>?4 ,x is cle> t !re is no support = ! view1 curr5t f ! "t ( ,james ,hutton onw>ds1 t nodul> fl9ts are =m$ by matt] 9 hot solutions ent]+ pre-exi/+ cavities 9 lime/one rocks4 ,b !re mu/ be cases :]e ! silicification ( lime/one has aris5 ?r\gh its p5etration by hot spr+s4 ,! pres5ce ( tabul> fl9t 9 jo9ts ( ! ,*alk %[s t wat] has import$ silica along easy l9es ( passage f "s o!r portion ( ! rock4 ,j z /ems ( trees become replac$ by *alc$onic silica1 s may b$s ( lime/one be conv]t$ into fl9t1 especially 9 volcanic areas4 ,a4 ,w4 ,rog]s#bf records t rec5t lime/ones =m$ 9 ! ,cape prov9ce by ! evaporation ( asc5d+ wat]s h already become silicifi$4 ,^! fl9ty rocks h be5 f\nd 9 ! ,kalah>i ,des]t & else:]e1 ?\gh n s\? ( ! ,orange ,riv]2 ! *emical *ange is probably due to ! "* ( local wat] r ?an to temp]ature4 ,yet x is rem>kable h[1 9 ! va/ majority ( in/ances1 ! p>tial or complete silicification ( a lime/one may be trac$ to an int]m$iate re/+ /age ( ! silica 9 ! =m ( skeletons ( ! vegetable diatoms or ! animal sponges or radiol>ians4 ,! decay ( fl9t itself1 by ! removal ( "p ( its sub/ance 9 solution1 is ! cause ( ! :ite surface on specim5s f ! ,*alk1 & ( ! crumbl+ :ite residues f\nd 9 c]ta9 gravels4 ,?is process has be5 fully discuss$ by ,j4 ,w4 ,judd1 :o believes t ! mat]ial remov$ is silica 9 ! opal9e condition#bg4 ,,lime/one ,,& ,,sc5]y ,lime/ones 9 ! field are *>act]is$ by jo9ts :i* trav]se consid]able ?icknesses ( /rata1 until "s %aly b$ is met )1 9 :i* e>?-/resses _c set up su* cont9u\s planes ( fracture4 ,s9ce ! conditions ( deposition may rema9 con/ant = a long "t 9 op5 seas1 & s9ce /ratification _c be obvi\s until ^! conditions *ange1 lime/ones may h a massive "* t is exceptional among s$im5t>y rocks4 ,9 "s cases1 h[ev]1 :]e muddy riv]s 9 times ( flood h br\ght 9 detritus f ! l&1 rapid & no d\bt seasonal alt]nations ( %ale & lime/one may be obs]v$4 ,! ,*alk ( nor?-we/]n ,europe rema9s typically s(t1 l5d+ itself to cliff-=mation along ! coa/1 :]e l&slides are frequ5t ?r\gh und]cutt+ f bel[4 ,7 x n = ! developm5t ( fl9ts along /ratification-planes1 x w\ld be impossible at a di/ance to detect any b$d$ /ructure 9 ! rock4 ,its repres5tatives 9 ea/]n ,france1 9 ! nor? zone ( ! ,alps1 or 9 ! c5tral ,ap5n9es1 are compress$ into f> m resi/+ masses1 & re> !mselves z t]rac$ crags & %e] rock-walls1 9 :i* ! /ructure due to v]tical jo9ts is p>am\nt4 ,! ,engli% ,*alk wea!rs into r\nd-back$ d[ns1 clo!d ) ?9 grass1 & holl[$ into combes by /reams t h long ago run dry4 ,! soil owes h>dly any?+ b its abundant fl9ts to ! :ite lime/one rock on :i* x lies4 ,residual clays & s&s d]iv$ f ! break+ up ( lat] b$s all[ ( cultivation "h & !re1 & bee*woods fl\ri% ev5 on ! cre/s ( ! high d[ns4 ,b wat] s9ks freely into ! gr\nd1 & may s f> saturate ! mass z to appe> aga9 9 wet seasons 9 holl[s ( ! surface z tempor>y spr+s or b\rnes4 ,:5 deep wells are sunk & pump+ is begun1 x is f\nd t ! supply v>ies greatly 9 diff]5t spots "u seem+ly uni=m conditions4 ,ev5 9 s p]meable a mass1 !re are wat]ways :]e maximum fl[ occurs4 ,*annels :]e wat] soaks 9 f above1 or weak places 9 ! ro(s ( und]gr\nd wat]c\rses1 become m>k$ at ! surface by s9k+s kn[n z swall[-holes4 ,^! increase 9 size ) "t1 & are ab&on$ to ! gr[? ( scrub & trees4 ,among m consolidat$ lime/ones1 z we h h9t$1 ! jo9ts are effective 9 promot+ bold rock-sc5]y4 ,! absorptive p[] ( ! rock1 r ?an its h>dness1 prev5ts x f be+ wa%$ away4 ,wat] t might r\nd ! edges ( esc>pm5ts & s5d d[n taluses to modify ! slopes s9ks into ! gr\nd & works out passages by solution4 ,on level surfaces1 ! solubility ( lime/one 9 wat] *>g$ ) c>bon dioxide f ! atmosph]e is app>5t by ! =mation ( pitt$ holl[s1 ) edges betwe5 !m t gr[ %>p] until !y are worn ?r\gh4 ,:]e a ra9-drop fir/ secures a re/+-place1 its successors deep5 ! little holl[4 ,wat] lies 9 ?is aft] e %[]1 work+ its way g5tly d[nw>ds4 ,9 "t ! rock may seem bor$ into z if prep>$ = bla/+2 ! holes unite to =m v]tical grooves1 & ! surface is cut deeply into fanta/ic =ms4 ,! face ( ! rock1 =m$ by wea!r+ on a valley-side or t[>ds ! sea1 or occurr+ on any mass t is be+ cut back & r$uc$ by d5udation1 is likely to be v]tical1 or at any rate p]p5dicul> to ! b$d+4 ,! =m ( ! surfaces ( ! b$s is p]petuat$ by _! fairly uni=m l[]+ ?r\gh solution4 ,! result is t /ratification surfaces & planes p]p5dicul> to !m control 9 a v m>k$ degree ! sc5]y ( lime/one l&s 7,fig4 #a74 ,illu/ration3 ,fig4 #a4 ,surface ( ,lime/one ,plateau4 ,causse du ,l>zac1 ,aveyron1 ,france4 ,:]e ! b$s are level1 ) occasional p>t+s ( a slightly diff]5t composition1 ! c\ntry w develop t]races1 l ^? ( ! ,burr5 9 nor!rn ,cl>e4 ,:]e !y are fold$1 z 9 ! ,juras1 sc>ps & dip-slopes foll[ "o ano!r picturesquely1 ! wea!r$ edge ( ! b$1 ! true esc>pm5t1 be+ sometimes at an angle z /eep z t ( ! dip4 ,h5ce a false effect ( %>p peaks is produc$1 :5 ^! edges are se5 end on at a di/ance4 ,! t]race-/ructure may be se5 9 m9iature =ms ^u a rocky %ore1 :]e ! blocks loos5$ f ! esc>pm5ts ( ! successive b$s are c>ri$ away by ! waves4 ,fro/-action is p[]ful 9 l>g] in/ances1 & s5ds d[n huge blocks ^u ! l[] t]races4 ,a comb9ation ( %ale b&s & massive lime/ones1 especially ) a dip outw>d f ! highl&1 leads to de/ructive l&slips1 s9ce ! slop+ surface ( %ale is lubricat$ by wat] t passes ?r\gh ! lime/one 7see ,fig4 #i74 ,outw>d slips ( ! coa/ are ?us common 9 ,antrim1 & h be5 ext5sive ne> ,axm\?1 two regions :]e *alk re/s ^u ,liassic clays4 ,brok5 gr\nd1 !n1 occurs freely "u lime/one sc>ps1 & ! fall+ blocks (t5 prev5t ! gr[? ( trees4 ,! fre%ness ( ! rock-face above & ( ! talus bel[ calls att5tion to spots :]e d5udation is mo/ active4 ,diff]5ces 9 ! con/itution ( ! b$s are indicat$ by diff]5ces ( ! slope =m$ by d5udation on ! rocky walls4 ,! huge caons ( ,arizona af=d effective illu/rations4 ,illu/ration3 ,fig4 #b4 ,rav9e 9 ,lime/one4 ,caon ( ! ,d\rbie1 ,aveyron1 ,france4 ,^! caons owe mu* ( _! "* to ! pres5ce ( v]tically jo9t$ lime/one4 ,! small ra9fall ( ! region has all[$ ! riv]s to deep5 _! *annels ahead ( ! we>+ back ( ! walls4 ,yet ev5 :]e valleys are wid5$ by ra9 & o!r atmosph]ic ag5ts1 ^? =m$ 9 lime/one w ma9ta9 ! "* ( rav9es4 ,9 ! valley-sides ( ,d]by%ire1 or ( ! ,franconian plateau1 or ( ! ,arve ne> ,sallan*es1 :]e ! crags rise a mile or m above ! /ream1 we see h[ caon-cutt+ is assi/$ by ! jo9ts 9 lime/one4 ,! rav9e ( ! ,d\rbie1 ea/ ( ,millau 9 ,aveyron1 9 ! romantic region ( ! ,causses1 is a w9d+ gorge two ?\s& feet 9 dep? 7,fig4 #b74 ,t ( ! ,t>n1 a little to ! nor?1 has only rec5tly be5 p5etrat$ by a road1 cut out = ! mo/ "p 9 a v]tical rock-wall4 ,:5 we obs]ve1 especially f ! /ream itself1 ! details ( ^! %e] valley-sides excavat$ 9 lime/one1 we aga9 & aga9 detect evid5ces ( solution4 ,high above ! pres5t wat]-level1 ! rocks are r\nd$1 & are (t5 und]cut1 s t !y ov]hang 7,fig4 #c74 ,9 ,mill]sdale 9 ,d]by%ire1 above grass-gr[n taluses1 ! surface is /ill smoo? to ! h&1 & we c picture ! wat] swirl+ aga9/ x1 & wa%+ x away1 z x does n[ 9 ! bottom ( ! grim rav9es ( ,c>niola4 ,x has be5 sugge/$1 inde$1 t "s lime/one caons repres5t und]gr\nd wat]ways1 ! ro(s ( :i* h fall5 94 ,?is may be true ( ! f9e gorge ( ,*$d>1 & 9 "s cases is prov$ by ! exi/5ce ( rock-ar*es bridg+ across ! holl[ ( ! /ream4 ,illu/ration3 ,fig4 #c4 ,wat]worn ,cliff ( ,lime/one4 ,rav9e ( ,mill]sdale1 ,d]by%ire4 ,! *>act]s ( an unmitigat$ lime/one region are be/ se5 :5 we travel ea/ ( ! ,adriatic4 ,"h :at h be5 /yl$ ! k>/ l&scapes become prom95t1 & may be foll[$ ?r\gh ! ,greek isles to ! ,levant4 ,some?+ ( ! k9d is realis$ 9 ! t]rac$ l&s betwe5 ! ,rhne & ! upp] rea*es ( ! ,durance2 lav5d] bu%es =m dull-gre5 spots on almo/ b>r5 hills1 & ! grey walls ( old /one-built t[ns are b>ely di/+ui%able aga9/ equally grey hillsides4 ,b t[>ds ,trie/e ! lime/one l&s are b>] /ill4 ,! small am\nt ( insoluble matt] yield$ by ! rock may accumulate 9 swall[-holes1 :i* are "h call$ dol9as1 a ,slavonic ^w really mean+ valleys4 ,?is residue appe>s 9 ! dol9as z a r$ clayey e>?1 ! t]ra rossa ( ! ,italian-speak+ ,dalmatian coa/4 ,b on ! surface ( ! plateaus x is wa%$ or bl[n away z soon z x is extract$ f ! lime/one4 ,a4 ,grund#bh has sugge/$ t ! frequ5cy ( fro/-action 9 m nor!rn areas all[s surfaces ( lime/one to be cumb]$ ) loose blocks among :i* soil-pat*es may ga!r2 h5ce we d n f9d k>/-features on ! plateaus ( c5tral ,bav>ia1 ,*ampagne1 or ! ,cotteswold ,hills4 ,some?+ approa*+ to a k>/ appe>s 9 ! w9d-swept levels ( s\!rn ,galway & ( ,cl>e1 & exposure to /rong w9ds has probably a good deal to d ) ! orig9 ( ! ,causses & ! ,illyrian k>/l&s4 ,at ! same "t1 ! am\nt ( impurity 9 ! lime/one mu/ /rongly influ5ce ! result+ l&scape4 ,! noble woods 9 ! lime/one holl[s ( s\!rn ,irel& are r5d]$ possible by ! clay soils d]iv$ f ! lime/one1 z mu* z by ! %elt]$ nature ( ! gr\nd4 ,illu/ration3 ,fig4 #d4 ,lime/one ,c\ntry ,dissect$ by ,rav9es4 ,k>/l& ( ,h]cegov9a1 f ! ,makl5 ,pass4 ,9 typical k>/l&s1 wat] s9ks 91 & em]ges aga9 on l[ gr\nd1 :]e ! surface-=ms cut ! level ( ! subt]ranean wat]-table4 ,/reams t manage to hold _! own = a "t on ! upl&s (t5 disappe> into ! clefts4 ,m>%es may occur 9 holl[s1 b may h no outlet1 except 9 v]tical directions1 upw>ds by evaporation & d[nw>ds ?r\gh ! dol9as4 ,! dol9as correspond1 z ! ,slavonic %eph]ds s aptly p]ceiv$1 to ! riv]-valleys ( m normal areas4 ,! l&scape ( fl[+ /reams has to be s\ght = 9 a my/]i\s und]world1 ( :i* we c ga9 only a few glimpses4 ,:at we "k is l>gely due to explor]s ( s+ul> ent]prise & res\rce1 notably ,e4 ,a4 ,m>tel & ! spelologi/s :om he has inspir$4 ,a view ov] ! plateau ( ,h]cegov9a %[s u h[ deep gorges1 r ?an ord9>y riv]-valleys1 are preval5t :]e important /reams run across a k>/l& 7,fig4 #d74 ,! roads are c>ri$1 :]e possible1 along ! rav9es1 & ! c\ntry possesses a d\ble life1 t ( ! broad upl&s1 :]e tanks h to be made to pres]ve ! wat]1 & t along ! comm]cial highways1 f\r or five ?\s& feet bel[4 ,ev5 beside ! riv]s !re is a s5se ( desolation 9 ! b>r5 :it5ess ( ! rocks4 ,! sunlight /rikes on ! wall ( "s !atre ( ! lime/one1 c>v$ out 9 old times by a side-swirl ( ! /ream1 & ! holl[ gl>es l a :ite furnace 9 ! hills4 ,! riv] 9 summ] %r9ks among broad /ony rea*es1 to :i* ?9-flank$ %eep are driv5 = a scanty pa/ure4 ,its cle> gre5 wat] gives no promise ( alluvium = its banks4 ,lime/one1 ev5 9 temp]ate ,europe1 may create ! features ( a des]t l&4 ,! mo/ extraord9>y rock-sc5]y 9 ,europe is due to lime/one 9 ! dolomitic /ate4 ,x is n cle> if ! crags & p9nacles ( ,tyrol are caus$ by ! *ange f calcium c>bonate into dolomite1 :]eby a granul> mass has aris51 wea!r+ freely along its v]tical jo9ts4 ,x may well be t ^! compact lime/ones h develop$ an exceptionally jo9t$ /ructure "u e>?-/resses1 & t fault+ has int5sifi$ _! t5d5cy to break up into =t-l blocks4 ,/ratifi$ masses ( m normal ,rhtic lime/ones (t5 provide a t]rac$ /ructure ne> ! m\nta9-cre/s2 b 9 ?\s&s ( feet ( und]ly+ dolomite v]tical clefts prevail entirely ov] planes ( b$d+4 ,if1 z is extremely probable1 ^! dolomite-rocks arose f ! composite masses t we /yle coral-reefs1 /ratification 0 none ! less a m>k$ feature z _! lime/one grew 9 ?ickness4 ,?is /ructure is /ill pla9ly visible2 b ! jo9ts h be5 wid5$1 & ! mass is cut up into /up5d\s p9nacles & dom9at+ t[]s4 ,! ,drei ,z9n5 ne> ,l&ro1 ! deeply not*$ wall ( ! ,langk(el & ! ,plattk(el1 ris+ f\r ?\s& feet above a grassy upl& ( normal ,l[] ,triassic /rata1 & ! ov]hang+ cre/s ( ! ,sett ,sass above ,bu*5/e91 are types ( a c\ntry :]e dolomite is pre-em95t1 & :]e ! zone ( /eep rock-wea!r+ is m>k$ by ! mo/ fanta/ic =ms4 ,,on ,,m>bles ,any lime/one ! m>k+s or col\r ( :i* r5d] x suitable = ornam5tal purposes passes z a ,m>ble4 ,fossil m>bles are (t5 m]e grey lime/ones1 9 :i* ! /ems ( cr9oids1 or ! curv$ sections ( %ells1 or ! radiat+ patt]ns due to corals1 please ! eye ) _! v>iety on a poli%$ surface4 ,! ,purbeck ,m>ble t 0 s mu* us$ z a grey foil to ! massive :ite columns ( ca!drals ?r\gh\t ,engl& is simply a fre%wat] lime/one1 ( no great m]it z a build+ /one1 cr[d$ ) ! %ells ( ,palud9a4 ,! black m>bles are lime/ones col\r$ by "o or two p] c5t4 ( c>bon1 d]iv$ f ! decay ( organisms1 & :ite %ells may /& out 9 !m conspicu\sly1 9 contra/ ) ! gr\nd4 ,! r$ m>bles ( ,plym\? & ( ,cork h become iron-/a9$1 & at ! same "t second>y cry/allisation has de/roy$ _m ( _! orig9al features4 ,9 ,little ,isl&1 ne> ,cork city1 e>?-movem5ts h cru%$ ! mass1 :i* 9 consequ5ce %[s signs ( solid fl[4 ,! break+ ( a cry/all9e lime/one "u su* /resses furni%es u ) _m h&some m>ble ,breccias4 ,! abrupt juxtaposition ( angul> masses ( v>i\s col\rs1 torn f b$s orig9ally di/9ct1 r5d]s "s ( ^! rocks almo/ too />tl+ = ! decoration ( rooms ( mod]ate size4 ,!re seems no su* ?+ 9 nature z amorph\s c>bonate ( lime1 & all lime/ones are !re=e =m$ ( cry/all9e p>ticles2 b ! fur!r cry/allisation ( ?is mat]ial produces a true m>ble1 9 :i* all traces ( fossils may be lo/4 ,heat & pressure und]gr\nd probably facilitate ?is *ange1 s9ce ev5 s(t *alk is conv]t$ by igne\s dykes into granul> m>ble4 ,b :]e ! pressure is accompani$ by ! possibility ( movem5t1 ! %e>+ action breaks d[n ! gra9s1 & a m delicate /ructure results4 ,we h already se5 7p4 #ce7 h[ dolomite may und]go /rik+ m9]al *anges ?r\gh advanc$ metamorphic action4 ,lime-g>nets1 wolla/onite1 diopside1 & o!r silicates simil>ly develop 9 ord9>y lime/ones expos$ to ! intrusion ( an igne\s magma4 ,! extreme *anges 9 su* rocks w be describ$ :5 amphibolites are dealt )4 ,,*apt] ,,iii ,,! ,,s&/ones ,,! ,,orig9 ,,( ,,s&s ,! ess5tial *>act]i/ic ( ,s&/one is t x consi/s ma9ly ( detrital gra9s ( qu>tz1 or occasionally ( gra9s ( *alc$onic silica 7fl9t72 ^! are f\nd to scrat* ! /eel blade ( a knife1 & are n affect$ by boil+ 9 ord9>y acids4 ,! gra9s usually become clean] 9 ! boil+ process1 s9ce ! cem5t t has b\nd !m toge!r is liable to be de/roy$4 ,?is cem5t may cause eff]vesc5ce1 be+ (t5 =m$ ( *emically deposit$ calcium c>bonate4 ,:5 we consid] ! di/ribution ( qu>tz 9 nature1 we look to igne\s & metamorphic rocks = ! orig9 ( ! gra9s 9 s&/one4 ,qu>tz is "o ( ! commone/ m9]als2 b 9 granite & qu>tz-diorite x r>ely =ms m ?an half ! bulk ( ! rock1 felsp> & mica & hornbl5de be+ its associates4 ,ve9s ( qu>tz 7qu>tz-rock7 trav]se _m rocks1 & become brok5 up into granul> =ms on wea!r+2 b !y are inconsid]able 9 comp>ison ) ! bulk ( ! slates or s*i/s 9 :i* !y lie4 ,mica-s*i/s contribute a good deal ( qu>tz-s& :5 !y decay2 b ?is is mix$ ) f]rug9\s clayey matt]1 & ! soils produc$ are yell[ loams4 ,we are easily impress$1 !n1 by ! enorm\s am\nt ( d5udation t 0 requisite to produce our exi/+ s&/ones4 ,?\gh n[adays s&/ones c be built up by ! decay ( old] rocks ( ! same k9d1 ! qu>tz mu/ h come orig9ally f igne\s or metamorphic s\rces4 ,ev5 9 ! metamorphic rocks1 a l>ge "p ( ! qu>tz is probably detrital4 ,! microscopic *>act]s ( ! qu>tz 9 s&/one commonly atte/ its orig94 ,! m9ute liquid inclusions1 ) mov+ bubbles1 t arise 9 ! qu>tz ( igne\s & metamorphos$ rocks1 are easily se5 9 sections ( s&/one4 ,9 "s qu>tzites1 ^! inclusions run 9 cont9u\s b&s f gra9 to gra91 & h cle>ly aris5 s9ce ! detritus 0 cem5t$4 ,b 9 ord9>y s&/ones ! inclusions 9 "o gra9 h no relation to ^? 9 its neighb\rs4 ,! felsp>s1 moreov]1 ( igne\s rocks are commonly f\nd1 z roll$ fragm5ts1 9 s&/one4 ,_! gra9s are usually :it] & dull] ?an ^? ( qu>tz1 & may easily be di/+ui%$ by ! nak$ eye4 ,small gleam+ plates ( mica f ! p>5t rock may accumulate ) ! qu>tz gra9s4 ,! d>k micas ( decay+ rocks1 ri* 9 iron & magnesium1 toge!r ) m9]al silicates ( calcium1 magnesium1 & iron1 su* z ! amphiboles & pyrox5es1 =m on hydration s(t gre5 *lorite4 ,?is m9]al1 9 films & easily de=m$ flakes1 at times occurs z a sort ( gr\ndwork to ! co>s] gra9s 9 s&/one1 & col\rs ! rock a delicate grey-gre54 ,f9e-gra9$ s&/ones ( ?is type are difficult to di/+ui% f alt]$ gre5/ones1 su* z basaltic &esites4 ,:5 ! qu>tz gra9s1 h[ev]1 are l>ge1 z 9 ! grits qua9tly /yl$ 9 old days greywacke1 !y =m a ready clue to ! orig9 ( ! rock4 ,nature sifts ! products ( decay s ?or\ghly1 on any slope expos$ to w9d or ra91 t ! f9e/ mat]ials are c>ri$ f> away1 & ! undecomposable qu>tz rema9s pr$om9ant4 ,! alluvium 9 ! upp] rea*es ( /reams is ?us f> m s&y ?an ! mix$ mat]ial suppli$ at ! outset f ! surr\nd+ rocks4 ,! m rapid fl[ ( ! wat] on ! /eep] upl& slopes naturally removes ! mud into ! l[l&4 ,:5 ! detritus1 /ill some:at mix$1 rea*es a sea-%ore1 wave-action is rapidly effective4 ,be=e ! cont9ual wa% & p\nd+ ( ! wat]1 any residual clay1 & ! f9ely comm9ut$ portion ( ! qu>tz1 are c>ri$ d[n ! coa/al slope4 ,! col\r ( ! sea aft] /orms is suffici5t evid5ce ( ! "w t x p]=ms4 ,bea*es1 !n1 arrive at a great simil>ity ( type4 ,! invit+ yell[ s&s1 =m$ ( comp>atively co>se mat]ial1 occur alike (f %ores =m$ ( *alk1 slate1 granite1 or b\ld]-clay4 ,illu/ration3 ,fig4 #e4 ,s& ,develop+ f ,s&/one1 9 semi-arid climate4 ,ne> ,la+sburg1 ,cape ( ,good ,hope4 ,f ! beg9n+ ( s$im5tation1 s&s h ?us t5d$ to accumulate1 & to become cem5t$ into s&/ones4 ,^! rocks1 9 turn uplift$ & expos$1 h yield$ o!r s&/ones4 ,s9ce co>se s& does n travel f> f ! region :]e x is wa%$ out ( ! p>5t rock1 a ?ick mass ( s&/one ext5d+ ov] _m squ>e miles may wa/e away1 & yet become p]petuat$ 9 ! di/rict4 ,s&9ess ?us begets s&9ess1 & ! physical conditions due to ! pres5ce ( s&/one may prevail ?r\gh long geological epo*s 7,fig4 #e74 ,( c\rse1 a subm]g5ce b5ea? ! sea may *ange all ?is 9 a brief "t2 b wr9kl+s ( ! cru/1 rais+ ! s&/ones into sev]] atmosph]ic levels1 may only accel]ate _! decay & r5d] ! surr\nd+ l&s m s&y4 ,,! ,,cem5t+ ,,( ,,s&s ,! cem5t ( s&/ones is v v>i$4 ,on our mod]n coa/s1 spr+s dra9+ f a lime/one l&1 or ev5 runn+ ?r\gh banks ( brok5 %ells1 w deposit calcite 9 ! int]/ices ( ! bea*1 until slabs & %elves ( conglom]ate & s&/one arise 9 defiance ( ! waves4 ,on coa/s :]e calcium bic>bonate is abundant1 x may be precipitat$ by any cause t dim9i%es its solv5t4 ,m]e evaporation1 & ! escape ( c>bon dioxide f ! wat] z x is scatt]$ into spray1 lead to ! deposition ( a cem5t betwe5 ! gra9s ( s&4 ,z ,l9ck#f %[s1 calcite is ?us laid d[n 9 temp]ate wat]s1 :ile aragonite =ms fibr\s cry/als betwe5 ! detrital fragm5ts on ! flanks ( tropic isles4 ,aragonite may also arise f ! action ( ammonium c>bonate or sodium c>bonate on calcium sulphate or calcium *loride 9 sea-wat]4 ,s&s ?us become cem5t$ by "o or o!r =m ( calcium c>bonate4 ,!y include1 moreov]1 calc>e\s alg1 =am9if]a1 & fragm5ts ( coral & sea-%ells4 ,fossil %ells are usually repres5t$ 9 old] s&/ones by m]e ext]nal & int]nal m\lds4 ,! texture ( ! rock all[s ( _! be+ dissolv$ 9 p]colat+ wat]s1 :ile 9 clays belong+ to ! same geological s]ies !y may be exquisitely pres]v$4 ,9 %all[s1 & especially 9 lakes1 :]e soluble salts ( iron become readily oxidis$1 br[n iron ru/1 ! m9]al limonite1 is cont9ually =m+ at ! surface & s9k+ to ! bottom1 :]e x firmly cem5ts ! s&4 ,a gr\p ( bact]ia#bi extracts iron 9 ?is =m f ! wat] ( fre%wat] lakes & swamps1 & greatly aids 9 its accumulation4 ,?\gh a r$ col\r may appe> also 9 m>9e deposits1 masses ( r$ & purple conglom]ates & s&/ones may reasonably be assign$ a fre%wat] orig94 ,su* rocks are usually f\nd to be devoid ( m>9e fossils1 & !y (t5 conta9 traces ( l& plants4 ,b>ytes 7b>ium sulphate71 :i* sometimes occurs 9 ve9s simulat+ ^? ( calcite1 is an occasional cem5t ( s&/one1 evid5tly aris+ f subt]ranean wat]s4 ,b&s ( fl9t 7*]t7 occur 9 c]ta9 s&/ones1 su* z ! ,hy! ,b$s ( ! ,engli% ,l[] ,gre5s& ,s]ies4 ,^! are due to ! cem5t+ ( c]ta9 lay]s by *alc$onic silica1 & ! s\rce ( ?is silica is se5 9 ! holl[ m\lds ( sponge-spicules1 & ! glauconitic ca/s ( _! canals1 t commonly rema94 ,g4 ,j4 ,h9de#cj %[s t 9 ! ,cretace\s examples1 z 9 s _m o!r fl9ts1 ! majority ( ! spicules are ( ! tetract9ellid type4 ,"u arid conditions1 z 9 p>ts ( ,africa1 loose sup]ficial s&s may become cem5t$ by calcium c>bonate1 or ev5 by silica1 br\ght up 9 wat] ris+ by capill>y action f bel[4 ,! s&-dunes ( ! coa/ ( our own isl&s1 :i* _c rema9 wet = long1 become 9 places t\gh5$ by a deposit ( calcite d]iv$ f ! abundant %ells ( l&-snails4 ,9 ! ,cape ( ,good ,hope#ca ! dunes1 z ,a4 ,w4 ,rog]s /ates1 are conv]t$ by invasions ( calcium c>bonate1 into h>d rock ?r\gh a di/ance ( _m feet f ! surface1 & :]e repeat$ly wett$ & dri$1 z happ5s :]e ! sea has encroa*$ ^u old dunes1 ! rock becomes int5sely h>d & wea!rs ) a peculi>ly jagg$ surface4 ,! ,g5]al ,po/ ,(fice & ! ,s\? ,african ,museum 9 ,cape ,t[n are ma9ly con/ruct$ ( ?is rec5tly consolidat$ rock4 ,! mod]n s&/ones cem5t$ by silica are /ill m int]e/+4 ,9 ! ,cape ( ,good ,hope1 & notably 9 ! ,kalah>i des]t1 !y =m ! int5sely h>d rock kn[n z ,qu>tzite#cb4 ,! cem5t+ mat]ial is true qu>tz1 :i* sometimes deposits itself 9 bipyramidal cry/als ab\t ! gra9s ( s&4 ,! molecules ( su* cry/als are arrang$ 9 cont9uity ) ! gr\p+ ( ^? 9 ! orig9al detrital gra91 z is prov$ 9 ?9 sections "u ! microscope by ! optical cont9uity ( ! qu>tz ( ! gra9 & ( its coat+4 ,z silica cont9ues to be deposit$1 ! coat+s int]lock1 & ! rock passes into true qu>tzite4 ,x is n[ (t5 difficult to detect ! outl9e ( ! orig9al gra9s4 ,su* sup]ficial qu>tzites may be t5 feet ?ick at mo/1 ) uncem5t$ s& bel[4 ,rog]s sugge/s t ! cem5t+ process may h orig9at$ 9 %all[ pools2 b x has obvi\s analogies ) t :i* =ms iron-pans & sup]ficial masses ( calcium c>bonate 9 regions :]e capill>y wat]s are subject to prolong$ evaporation4 ,h4 ,g4 ,lyons#cc has attribut$ ! cem5t+ ( p>ts ( ! ,nubian ,s&/one 9 ! des]t ( ,l[] ,egypt to ! silica set free by ! alt]ation ( ! felsp>s 9 ! rock4 ,?is *ange1 he sugge/s1 0 accel]at$ by ! infiltration ( sodium c>bonate ( local orig94 ,fossil trees 9 ^! /rata h be5 replac$ by silica4 ,a fur!r example is record$ by ,armitage#cd f ,victoria1 :]e friable f]rug9\s ,ca9ozoic s&s h be5 conv]t$ into qu>tzite4 ,?is type ( rock1 ! h>de/ kn[n1 & associat$ 9 our m9ds ) high antiquity & metamorphic action1 proves1 !n1 to be 9 process ( con/ruction at ! surface at ! pres5t day4 ,! obs]vations ( ,rog]s %[ t qu>tz & n m]e *alc$ony is deposit$ on ! gra9s ( s&4 ,! cry/all9e s&/ones ( ,p]mian & ,triassic age 9 ,engl& may1 !n1 h acquir$ _! rem>kable *>act]s at ! actual epo* ( _! accumulation4 ,?is is r5d]$ ! m probable by ! recognis$ occurr5ce ( arid conditions1 at any rate seasonally1 :5 ! /rata 9 "q 7 laid d[n4 ,^! ,engli% cry/all9e s&/ones 7 describ$ by ,h4 ,c4 ,sorby#ce1 :o %[$ t ! qu>tz deposit$ on ! detrital gra9s 0 9 optical cont9uity ) t ( ! gra9s !mselves4 ,j4 ,a4 ,phillips#cf reg>d$ ?is qu>tz z cry/allis$ out dur+ ! kaol9isation ( felsp>s4 ,! ph5om5a ( lat]isation1 h[ev]1 give u a fur!r sugge/ion z to ! orig9 ( ! second>y silica4 ,x is n[ well kn[n t tropical processes ( wea!r+1 ) alt]nations ( wet & dry seasons1 all[ alum9a to be set free f comb9ation ) silica1 lat]itic cru/s ?us aris+ on a great v>iety ( rocks4 ,! felsp>s ( a s&/one may1 "u su* conditions1 become lat]is$ r ?an kaol9is$1 alum9ium hydrate be+ left1 & ! silica pass+ into solution & appe>+ aga9 9 c]ta9 lay]s z cem5t+ qu>tz4 ,! almo/ complete disappe>ance ( silica f ! m advanc$ lat]ites %[s t x has be5 c>ri$ away else:]e1 & ! cem5t ( qu>tzite may ?us be d]iv$ f rocks at a consid]able di/ance4 ,j1 h[ev]1 z ! de/ruction ( silice\s sponge-spicules implies ! =mation ( fl9t1 s lat]isation implies silicification z a complem5t>y process4 ,! fact t second>y qu>tz 9 qu>tzite (t5 arises 9 ! rock itself is %[n by ! frequ5cy ( qu>tz-ve9s 9 qu>tzites1 :ile !y are almo/ abs5t f associat$ slates or s*i/s4 ,h5ce x appe>s t a removal ( silica goes on at "s po9ts1 lead+ to an infill+ ( all ! cracks & int]/ices at ano!r4 ,x is cle>1 !n1 t s&/ones1 accord+ to ! mode 9 :i* !y h be5 affect$ by p]colat+ wat]s1 may v>y f ! crumbl+ uncem5t$ condition1 kn[n z ,s&-rock1 to t h>de/ & mo/ resi/+ ( rocks1 qu>tzite4 ,! p]meability ( s&/one is responsible = a wide v>iety ( types4 ,,! ,,s&-,,gra9s ,,( ,,s&/one ,s&/ones are orig9ally p]meable by wat]1 n because !y possess a high p]c5tage ( pore-space1 or porosity1 b because ! pores betwe5 ! gra9s are l>ge4 ,wat] c ?us move easily by gravitation ?r\gh ! mass4 ,! capill>y rise or spread ( wat] is greate/ 9 mat]ials ( v f9e gra91 ?\gh 9 ^! x may be extremely sl[4 ,= ! mo/ effective rise ( wat] aga9/ gravity by capill>y pull1 a l>ge proportion ( p>ticles ab\t #jb mm4 9 diamet] %\ld be pres5t4 ,s&-gra9s1 h[ev]1 (t5 measure #e mm4 9 diamet]1 & ! f9e mud or highly comm9ut$ s& betwe5 ! co>s] matt] is ! cause ( ! spread ( wat] ?r\gh ! mass :5 ! supply comes f a subt]ranean wat]-table4 ,ra91 h[ev]1 is ( c\rse readily absorb$4 ,x disappe>s s rapidly on "s b>r5 s&/one areas1 coat$ z !y are by loose s&y soils1 t vegetation _c make a />t1 ev5 :]e wat] is suppli$4 ,daubre1 ,sorby1 & o!rs h /udi$ ! *>act]s ( s&-gra9s1 & x has be5 po9t$ out1 t agitat$ wat] buoys ap>t & c>ries =w>d by flotation gra9s ) a diamet] ( #a mm4 or less4 ,h5ce co>s] gra9s may become r\nd$ l pebbles1 by friction on ! bottom ( a /ream2 b small ones rema9 angul> ?r\gh\t geological p]iods1 & ev5 :5 transf]r$ f "o s&/one to ano!r4 ,:5 _! surfaces h be5 clean$ by boil+ 9 hydro*loric acid1 ! %>pness & irregul>ity ( ! qu>tz gra9s is /rik+ly app>5t4 ,m+l$ ) ^! gra9s1 9 addition to ! m9]als previ\sly m5tion$1 _m int]e/+ cry/als appe> t h become conc5trat$ 9 ! natural wa%+ processes4 ,m9ute col\rless zircons & br[n rutiles1 d]iv$ f granite1 h collect$1 ow+ to _! high specific gravity1 9 c]ta9 s&s4 ,magnetite & ilm5ite may d>k5 ! mass2 monazite & ?orite1 :i* are s\ght aft] = _! con/itu5ts c]ium & ?orium1 become simil>ly select$ 9 alluvial holl[s1 ow+ to _! d5sity ( #e4 ,:atev] ga!rs ?us 9 s&s may become pres]v$ 9 s&/ones1 & ! /udy ( ?9 sections ( ! latt] "u ! microscope is fruitful 9 sugge/ions z to _! orig94 ,"s s&/ones are rem>kable = _! highly r\nd$ & almo/ sph]ical gra9s4 ,j4 ,a4 ,phillips#ch comp>$ ^! ) ! w9d-worn gra9s ( des]ts1 :i* assume simil> =ms & a consid]able poli%4 ,l>ge quantities ( s& are c>ri$ f arid l&s into riv]s1 into lakes1 or into ! sea1 & h5ce well r\nd$ gra9s1 9 b$d$ rocks1 & ev5 9 m>9e s&/ones1 may h _h a des]t orig94 ,j4 ,w4 ,judd1 :5 exam9+ ! deposits ( ,l[] ,egypt = ! ,royal ,society1 comm5t$ on ! extreme fre%ness ( ! felspa?ic p>ticles 9 s&s accumulat+ 9 ra9less areas1 & rec5t obs]vations on ! soils ( semi-arid di/ricts %[ _! comp>ative pov]ty 9 clay4 ,en\gh has be5 said to indicate ! v>iety ( geographical consid]ations t may arise f ! exam9ation ( b$s ( s&/one4 ,! gra9s (t5 prove1 especially 9 ! co>s] types1 to be fragm5ts ( rocks r ?an isolat$ m9]als1 & ?us furni% a picture ( ! mat]ials t =m$ ! surface expos$ to d5udation4 ,! s&/ones ( f9e/ gra9 may be f\nd 9 b$s deposit$ almo/ on ! limits ( s$im5tation f ! l&1 :]e !y are int]lock$ ) mat]ial ( truly pelagic orig94 ,m>9e muds (t5 conta9 a high p]c5tage ( comm9ut$ qu>tz1 & ! /udy ( %ales & slates ( anci5t days %[s h[ ?is almo/ inde/ructible m9]al f9ds its way into b$s t might easily be classifi$ z clays#da4 ,,"s ,,*>act]s ,,( ,,s&/one ,e>?-/resses & %r9kage give rise to jo9ts 9 s&/one1 :i* may n be s clean & %e] z ^? 9 lime/one1 b :i* affect ev5 ! s(t] =ms4 ,cem5t$ s&-dunes ( mod]n date t5d to break away along v]tical planes4 ,firm] s&/ones give rise to /epp$ table-l&s & edges1 & ! resi/ance ( _m types to atmosph]ic decay r5d]s _! /ratifi$ /ructure /rongly app>5t4 ,small int]vals 9 ! process ( deposition1 or slight *anges 9 ! co>s5ess ( ! s& br\ght d[n by curr5ts1 give rise to lam9at$ & flaggy types4 ,:]e a broad %ore has be5 expos$ betwe5 tide-m>ks1 ! dry+ & compact+ ( ! surface be=e ! next lay] is laid d[n enables ! latt] to take a m\ld ( ! inequalities ( t bel[4 ,ripple-m>ks1 sun-cracks1 ra9-pr9ts1 & ! footm>ks ( animals1 are (t5 pres]v$ 9 ?is mann]4 ,:]e ! %ore is subsid+1 !y may p]si/ ?r\gh hundr$s ( feet ( /rata4 ,naturally1 ! be/ examples ( ^! ca/s1 & ( ! orig9al /ructure 9 ! und]ly+ b$1 occur :]e a little mud has be5 laid d[n ov] ! s&y flat4 ,clay by itself1 if damp1 does n reta9 ! impressions suffici5tly long1 &1 :5 once ?or\ghly dri$1 x crumbles :5 ! next wat] ov]fl[s x4 ,b a f\ndation ( firm s& ) a ?9 mud-lay] on its surface1 z may be recognis$ 9 "s ,triassic deposits1 furni%es excell5t records ( local wea!r or ( ! movem5ts ( errant animals4 ,on ! flat %ores ( lakes 9 a semi-arid climate1 ! wat] may retreat = miles1 & return1 p]haps mon?s aft]w>ds1 :5 ra9s 9 ! hills h giv5 x a new burd5 ( detritus4 ,"u su* conditions1 broad sun-crack$ flats may be pres]v$1 ) p]haps "s plant-rema9s betwe5 successive lay]s#ich4 ,! ca/+s & tracks ( worms1 & ! tubes ( bor+ species1 :i* are sometimes infill$ by s& ( a diff]5t col\r1 are common 9 s&/ones ( all ages4 ,,silice\s ,,conglom]ates ,! deposits ( wave-swept bea*es leave u ,conglom]ates =m$ ( v>i\s types ( pebbles1 among :i* qu>tz-rock & qu>tzite naturally pr$om9ate4 ,9 "s cases ! pebbles are ready =m$ :5 !y rea* _! re/+-place4 ,!y come roll+ out f lat]al torr5ts into ! quiet] wat]s ( a ma9 valley1 z may be se5 9 summ] 9 ! broad pebble-banks ( ! nor? ,italian /reams4 ,!nce !y are wa%$ by occasional floods into ! great conflu5t deltas t con/itute ! upp] "p ( an alluvial pla91 or into lake-bas9s1 :]e !y promptly settle along ! %ore4 ,b few su* pebbles1 except f pre-exi/+ conglom]ates or gravels on ! %ore-l9e1 actually rea* ! sea4 ,! roll$ /ones ^u sea-bea*es are mo/ly ! products ( m>9e action on ! spot4 ,:ile ! f9e s&-gra9s g seaw>d almo/ unh>m$1 ! detrital /ones1 (f]+ f> less surface 9 proportion to _! mass1 /rike on _! neighb\rs z e wave %ifts !m on ! bea*1 & soon assume a r\nd$ =m4 ,! conglom]ates ultimately consolidat$ may reveal /ratification only by ! g5]al arrangem5t ( _! pebbles4 ,^! c r>ely be sph]es1 s9ce !y are n z a rule turn$ ov]1 b are pu%$ ?is way & t until !y acquire a flat ellipsoidal %ape4 ,!y lie ) _! flatt] sides 9 planes p>allel to "o ano!r4 ,g5]ally1 h[ev]1 alt]nations ( co>s] & f9] b$s m>k out ! /ratification ev5 9 conglom]ates4 ,! s&s ( des]ts include abundant /ones & blocks ( rock1 & ! loose mat]ial becomes1 moreov]1 sift$ by ! w9d4 ,true des]t s&s may accumulate at "o po9t1 ! v f9e/ loamy mat]ial may be c>ri$ away /ill f>!r to =m fields ( f]tile lss1 & a rock-des]t1 =m$ ( /ones re/+ on b>e surfaces1 may rema9 9 l>ge areas ( ! arid region4 ,! loose /ones "h assume a *>act]i/ic %ape1 & h be5 kn[n "u ! ,g]man "n ( ,dreikant]4 ,!y are fairly flat bel[1 & are cut away above by ! drift+ s& into a =m resembl+ a gable ro( dipp+ at bo? ends4 ,_! surfaces are *>act]i/ically et*$4 ,dreikant] h be5 f\nd 9 b$s t 7 =m]ly ascrib$ to deposition on ! %ores ( lakes1 & x mu/ n[ be borne 9 m9d t cont9u$ attrition by drift+ s& affects mix$ detritus on a l& surface mu* z ! wa% ( wat]s does ^u a bea*4 ,c]ta9 mat]ials are cut away m rapidly ?an o!rs1 & ! residue assumes a m & m qu>tzose type4 ,9 ?is way1 s&/ones1 & conglom]ates 9 :i* fragm5ts ( qu>tzite & ve9-qu>tz pr$om9ate ov] o!r con/itu5ts1 may arise z olian bea*es on dry l&4 ,,s&/one ,,& ,,! ,,l&-,,surface ,! p]meability ( s&/one has already be5 ref]r$ to4 ,! surface (f]$ by x is typically dry1 & ! soil1 consi/+ ma9ly ( gra9s ( silice\s s&1 c nei!r reta9 ! ra9 t falls nor draw up wat] f bel[4 ,! idea t trees c fl\ri% on s&/one soils because !y require no?+ f ! soil itself is ( c\rse errone\s4 ,!y dep5d to a l>ge ext5t ^u ! mat]ials set free by ! decay ( c]ta9 gra9s1 or ( ! cem5t ( ! und]ly+ s&/one4 ,9 proportion z ! s&/one is impure1 t is1 ! m its con/itu5ts deviate f pure qu>tz1 ! m *ance !re is t x w provide a f]tile soil4 ,on ! :ole1 h[ev]1 areas ( silice\s conglom]ate & s&/one are giv5 ov]1 ev5 9 temp]ate climates1 to =e/ & hea!r4 ,:]e ! s&/one is /ill 9 ! s&-rock /ate1 b>e pat*es are likely to appe> ev5 9 ! hea? t has gr[n across x1 & f ^! ! w9d c>ries away %ift+ s&s4 ,ev]yone famili> ) ! ,c>bonif]\s areas ( ! ,engli% midl&s w realise ! influ5ce ( h>d grit & s&/one 9 =m+ edges across ! c\ntry4 ,! contra/ betwe5 ^! esc>pm5ts & ! slopes ( crumbl+ %ale t (t5 und]lie !m gives div]sity to ! sc5]y ( ,yor$ale & ! ,peak4 ,! m yield+ s&/ones ( ,cretace\s age r\nd ab\t ! ,weald1 or at ! foot ( ! ,*ilt]n ,hills ne> ,woburn1 =m r\nd$ hills1 mo/ly clad ) woods ( conif]\s trees4 ,9 ,surrey1 unpav$ c>t-tracks1 us$ = c5turies1 h cut gullies 9 ! unconsolidat$ ,folke/one ,s&s4 ,! und]ly+ ,hy! ,b$s1 h[ev]1 /& out betwe5 ,reigate & ,guild=d z a bold esc>pm5t1 & x is int]e/+ to reflect t ?is f9e feature ( s\?-ea/]n ,engl& is probably due to ! *]t :i* ! b$s conta9 7see p4 #fb74 ,! local gr[? ( silice\s sponges 9 a ,l[] ,cretace\s sea enables ,lei? ,hill 9 our days to dom9ate ev5 ! ar* ( ,a%d[n ,=e/1 :]e ano!r unfill$ s&/one area rises 9 ! c5tre ( ! ,weald4 ,! s&s ( ,bag%ot ,hea?1 & num]\s simil> areas 9 ! ,p>is ,bas91 %[ h[ impossible x is to cultivate su* /rata1 ev5 ne> ! be/ ( m>kets4 ,! fl9t gravels t cov] mu* ( ! upl& 9 ! ,new ,=e/ may also be borne 9 m9d1 z pres5t+ ! wor/ features ( highly silice\s l&s4 ,9 a semi-arid climate1 or "o ) only seasonal ra9s1 ! processes by :i* s&/one begets s&/one t5d to develop des]t wa/es4 ,! soils produc$ by wea!r+ d n cake toge!r1 & are c>ri$ away by w9d dur+ ! dri] mon?s4 ,! b>e rock appe>s ov] broad surfaces1 j z x does 9 /orm-swept lime/one areas1 & any holl[ :]e %elt] is af=d$ t5ds to become fill$ ) s& 7see ,fig4 #e74 ,! hummocky & extremely irregul> surface ( "s ( our ,silurian areas1 su* z p>ts ( ! ,s\!rn ,upl&s ( ,scotl& & ! h>d-won f>ml&s ( ,d[n & ea/]n ,monaghan1 is due to ! pres5ce ( resi/+ s&/ones among ! %ales4 ,^! s&/ones1 pass+ into true grits1 are repeat$ly fold$1 & _! upturn$ edges h resi/$ ev5 ! passage ( glaci]-ice4 ,!y jut out along ! cre/s ( ridges1 & ev5 ! small] b$s furni% angul> fragm5ts to ! soils4 ,illu/ration3 ,fig4 #f4 ,silice\s ,conglom]ate4 ,*>act]i/ic wea!r+2 mora9e-blocks at ,c\m%+aun1 ,co4 ,wat]=d4 ,f> wild] sc5]y is =m$ by ! m cont9u\s s&/one masses ( ! ,h>le* ,b$s 9 we/]n ,wales1 :i* are grits s firmly cem5t$ t ! rock breaks across ! qu>tz-gra9s4 ,mu* ( ! ,old ,r$ ,s&/one is ( equally h>d quality 7,fig4 #f74 ,its purple or grey conglom]ates1 ! pebbles ( :i* are qu>tzite 9 a qu>tz cem5t1 =m b>e & rugg$ masses 9 ! ,great ,gl5 s\?-we/ ( ,inv]ness1 & are responsible 9 ,k]ry = "s ( ! wilde/ rock-sc5]y 9 ! ,briti% ,isles4 ,v>iations 9 co>s5ess all[ ( ! developm5t ( a m>k$ /ratification on ! wea!r$ m\nta9 sides1 & diff]5tial erosion ( ! b$s has tak5 place :]e ice has press$ aga9/ !m4 ,ev5 on precipices1 grassy l$ges may occur1 m>k+ b&s ( s&/one or %ale 9 ! conglom]atic mass4 ,! r$ s&/ones & conglom]ates t =m huge out/&+ bluffs f ,applecross to ! nor? ( ,su!rl& repres5t ! d5udation ( a pre-,cambrian m\nta9 region4 ,^! ,torridon ,s&/ones cov] a v irregul> surface ( old gneiss1 ) :i* _! almo/ level /rata are 9 /rik+ contra/4 ,p4 ,lake#ci has comp>$ !m ) ! deposits /yl$ da%t 9 ,balu*i/an & ,afghani/an1 :i* simil>ly fill up valleys & cov] hills1 z products ( ext5sive & rapid d5udation4 ,!re is mu*1 inde$1 to sugge/ t ! ,torridon ,s&/one1 "s #aj1jjj feet 9 ?ickness1 0 accumulat$ 9 a dry c\ntry on a cont95tal surface1 ) ! aid ( floods dur+ occasional ra9y seasons4 ,qu>tzite1 :i* fractures into small angul> blocks "u e>? /resses1 yields an intractable surface ( b>e rock & taluses ( %ift+ /ones4 ,! latt] sometimes crumble d[n into :ite s&1 :i* provides "s basis = ! gr[? ( hea!r4 ,! num]\s jo9ts1 indep5d5t ( ! b$d+-planes1 cause ! rock to break up almo/ equally on any expos$ slope1 & ! cre/s ( qu>tzite hills become typically conv]t$ into cones 7,fig4 #g74 ,view$ f a di/ance1 ! :ite taluses1 /ream+ d[n ev5ly f ! cre/s1 resemble caps ( sn[4 ,illu/ration3 ,fig4 #g4 ,qu>tzite ,cone4 ,croagh ,patrick1 ,co4 ,mayo4 ,! abs5ce ( soil & ! smoo?ness ( wea!r$ surfaces r5d] qu>tzite m\nta9s h>d to climb4 ,! uni=m cem5t+ ( ! rock leaves ! b$d+ ) little influ5ce on ! surface-features1 & rock-l$ges & %elves are r>e4 ,! travell] asc5ds ov] taluses ( angul> & ob/9ate blocks t[>ds slipp]y & inhospitable domes4 ,b ! wildness ( ! sc5]y w be 8 sure rew>d4 ,x is ( int]e/ to reflect t ! mat]ial ( ^! bold out/&+ m\nta9s may 9 c]ta9 cases h orig9at$1 9 all its h>dness1 9 ! levels ( a sun-p>*$ pla94 ,,*apt] ,,iv ,,clays1 ,,%ales1 ,,& ,,slates ,,*>act]s ,,( ,,clay ,,& ,,%ale ,! "q ( :at is a true ,clay has be5 mu* discuss$1 especially by agriculturi/s1 9 rec5t ye>s#ici4 ,! mat]ial1 z a rock1 is reg>d$ z a massive kaol91 &1 if pure1 %\ld h ! foll[+ p]c5tage composition3--silica #dfc1 alum9a #cih1 wat] #aci4 ,"s ,pipe-clays1 :ite & uncontam9at$1 closely approximate to ?is ideal4 ,true clays are v pla/ic :5 moi/5$1 & %r9k on dry+1 =m+ a compact mass ! p>ticles ( :i* d n fall ap>t4 ,:5 ?or\ghly dri$1 h[ev]1 & plac$ 9 wat]1 lumps ( clay break up readily2 ! wat] creeps 9 along _! capill>y passages & expels tra9s ( air-bubbles z x goes4 ,?is fact has be5 utilis$ 9 ! extraction ( fossils f a matrix ( /iff clay4 ,if ! clay ?us r$uc$ to p[d] is n[ puddl$ by ! f+]1 x aga9 =ms a closely adh]5t pla/ic mass4 ,! individual spaces betwe5 adjac5t p>ticles 9 a clay are v m9ute1 & ?is acc\nts = its practical imp]meability to wat]2 b ! total pore-space or porosity may am\nt to m ?an fifty p] c5t4 ( ! volume ( ! rock4 ,unless e>?-pressures h br\ght ! mass into ! condition ( %ale or slate1 ! t9y flaky kaol9 p>ticles1 & ! associat$ v small gra9s ( o!r m9]als1 h n %ak5 !mselves d[n into a closely aggregat$ /ate4 ,:5 moi/5$1 h[ev]1 & aga9 dri$1 ! surface-t5sion ( ! film ( wat] ab\t any gr\p ( gra9s1 increas+ z evaporation ?9s ! film1 draws ! gra9s ne>] to "o ano!r1 & a consid]able %r9kage ( ! mass results4 ,alt]nate wett+ & dry+ t5ds to make a clay less obdurate & /icky1 by increas+ ! numb] ( sep>ate aggregates ( gra9s4 ,! passages betwe5 ^! aggregates are no long] s m9utely capill>y1 & a clay soil becomes by ?is process di/9ctly light] f ! f>m+ po9t ( view4 ,! l>g] cracks caus$ by %r9kage greatly increase ! evaporation ( wat]1 by expos+ new surfaces1 :i* p5etrate deeply into ! clay4 ,(t5 ! mass %r9ks s z to develop hexagonal /ructure1 f ! dry+ surface d[nw>ds 7,fig4 #h74 ,! natural flocculation ( clays1 ! process by :i* comp\nd gra9s are =m$ 9 place ( individual soil-p>ticles1 is assi/$ by ! action ( wat] be>+ c]ta9 salts 9 solution4 ,calcium c>bonate is an excell5t flocculator1 & ?is fact has long l$ f>m]s to place burnt lime or p[d]$ lime/one on _! l&s4 ,sodium c>bonate1 on ! o!r h&1 is br\ght up 9 "s dry regions by capill>y action1 & ex]cises a rev]se effect1 keep+ ! m9ute p>ticles ap>t f "o ano!r1 & ?us promot+ ?or\gh clay9ess 9 ! clay4 ,exp]im5t has %[n t f95ess ( gra9 is responsible = mo/ ( ! *>act]s ( a clay1 & f ?is po9t ( view ! small size ( kaol9 flakes z comp>$ ) gra9s ( o!r m9]als w acc\nt = ! clay9ess ( ?is p>ticul> m9]al :5 x con/itutes a rock4 ,clays1 h[ev]1 :5 %ak5 up 9 a column ( di/ill$ wat]1 cause :at seems to be a p]petual cl\d9ess1 s9ce x rema9s aft] ! great bulk ( ! clay has settl$ d[n4 ,flocculation by salts alone removes x4 ,"s au?ors h urg$ t a colloid sub/ance1 am\nt+ p]haps to only "o or two p] c5t4 ( ! :ole clay1 imp>ts ?is di/9ctive "*4 ,su* colloids are believ$ to arise dur+ ! decomposition ( alum9\s silicates "u tropical & probably alkal9e influ5ces2 b !y are n kn[n to be associat$ ) ! processes by :i* kaol9 is =m$ f felsp>s4 ,illu/ration3 ,fig4 #h4 ,%r9kage-cracks 9 ,clay1 ) footpr9ts ( birds 9 ! =egr\nd4 ,tundra ( ,mim] ,bay1 ,spitsb]g54 ,a4 ,d4 ,hall#dj po9ts out t ! cl\d9ess is probably due to ! extreme m9ut5ess ( c]ta9 ( ! p>ticles4 ,true clay9ess ?us dep5ds on ! proportion ( gra9s small] ?an #jjb mm4 9 diamet]4 ,yet ,hall & ,russell look to o!r causes to expla9 ! cont9u$ susp5sion ( su* p>ticles 9 ! wat]1 & !y sugge/ ! pres5ce ( potassium & sodium silicates ( ! zeolite gr\p1 :i* lib]ate by hydrolysis a little alkali 9 contact ) a l>ge bulk ( wat]4 ,free alkalies prev5t flocculation1 & s enc\rage susp5sion ( ! p>ticles4 ,to ! ord9>y obs]v]1 a rock possesses ! prop]ties ( clay1 & is a clay1 if x conta9s m ?an =ty p] c5t4 ( p>ticles less ?an #ja mm4 9 diamet]4 ,b su* rocks are f\nd1 on *emical analysis1 to conta9 a l>ge am\nt ( kaol91 & ! old view1 t clays are massive kaol9s1 is ?us sub/antially correct4 ,none ! less1 clays are notably impure1 & 9 _m !re is a l>ge admixture ( qu>tz s&4 ,! kaol91 d]iv$ orig9ally f ! decay ( o!r silicates1 is r>ely fre$ f a v>iety ( m9]als & rock-fragm5ts t 7 associat$ ) x 9 its place ( orig94 ,gra9s ( qu>tz & unalt]$ felsp> a t5? ( a millimetre 9 diamet] di/9ctly light5 a clay soil1 on acc\nt ( _! relative co>s5ess4 ,a s&y clay is /yl$ a ,loam1 & a f9e-gra9$ loam furni%es ! ideal soil = ! g5]al purposes ( a f>m]4 ,x does n reta9 wat] too long ^u its surface1 nor does x dry too quickly aft] ra94 ,mu* ( :at we call b\ld]-clay proves to be 9 reality a loam4 ,t4 ,mell>d ,reade & ,p4 ,holl&#da h %[n t ev5 9 clays ( m>9e orig9 !re may be a consid]able proportion ( v f9e qu>tz s&4 ,calcium c>bonate1 usually occurr+ z f9e rock-du/ d]iv$ f lime/one1 or z m9ute %ell-fragm5ts1 may be m+l$ ) clay to =m a ,m>l4 ,! t]m is n a quantitative "o1 & may be appli$ to any clay t %[s a brisk eff]vesc5ce ) cold acids4 ,?\gh unpleasantly /icky :5 wet1 m>ls flocculate !mselves naturally by supply+ calcium c>bonate 9 solution to wat]s t pass ?r\gh _! crevices 7see p4 #hj74 ,! /ratification ( clays may be invisible ?r\gh\t consid]able masses1 unless s&y b$s are int]calat$ among !m4 ,yet1 :5 a lump ( clay is dri$ & !n plac$ 9 wat]1 z previ\sly describ$1 x w (t5 break up along p>allel planes1 :i* %[ t !re is a regul> arrangem5t ( its p>ticles4 ,! fact t s _m ( ^! p>ticles are platy becomes emphasis$ "u ! pressure ( subsequ5t s$im5ts1 :]eby ! platy surfaces ( ! p>ticles are br\ght into planes p>allel ) "o ano!r4 ,! clay !n becomes a ,%ale1 ) regul> planes ( fissility1 :i* are p>allel to ^? ( b$d+4 ,a c]ta9 am\nt ( de=mation ( ! rock accompanies ?is *ange1 fl[ be+ set up p>allel ) ! b$d+1 & includ$ fossils becom+ sometimes flatt5$4 ,?is de=mation is especially noticeable 9 ! case ( plant-rema9s4 ,%ales may 9 "t atta9 ! d5sity & fissile /ructure ( true slate4 ,! col\rs ( clays & %ales are ( consid]able int]e/4 ,blackness is (t5 due to organic matt]1 & especially to fragm5ts ( plants1 :i* reta9 _! woody /ructure & _! c>bonace\s "* :5 protect$ by clay f oxidation4 ,! blui% t9t ( clays is due to f9ely divid$ iron pyrites 7iron disulphide71 :i* may occasionally appe> z di/9ct cry/als or nodules ( "o or o!r ( its =ms1 pyrite or m>casite4 ,on oxidation1 limonite arises1 :i* col\rs ! mass br[n1 z is se5 9 ! upp] "p ( _m clay-pits4 ,! occurr5ce ( iron pyrites (t5 dates back to ! "t at :i* ! clay accumulat$4 ,n4 ,&russ[#db po9ts out t 9 ! ,black ,sea !re is an enorm\s supply ( decay+ organic matt] provid$ by ! float+ organisms ( ! upp] lay]s4 ,?is ra9s cont9ually d[n t[>ds ! floor4 ,! portion t rea*es dep?s ( ov] #ajj fa?oms escapes f ! voracity ( free-swimm+ organisms & arrives at ! region :]e bact]ia alone ab\nd4 ,^! bact]ia act on dissolv$ sulphates1 & also l>gely1 accord+ to ,&russ[1 on ! album5 ( ! decay+ matt]4 ,9 bo? cases1 sulphurett$ hydrog5 is produc$4 ,&russ[ treats ! r$uction ( ! m>9e sulphates z a m9or process1 due to ! ne$ t ! bact]ia h = oxyg5 9 ! deep wat]s1 :i* are insuffici5tly suppli$4 ,! sulphurett$ hydrog5 attacks ! salts ( iron1 & iron disulphide results4 ,"h we h an excell5t illu/ration ( h[1 9 deep bas9s1 ) imp]fect v]tical circulation1 black pyrit\s muds may arise1 devoid ( ord9>y fossils4 ,! dep?s ( ! ,black ,sea are practically poison$ by ! abundance ( sulphurett$ hydrog54 ,b num]\s cases ( %ales are kn[n to u :]e iron pyrites replaces ! %ells ( ammonites or =ms complete ca/s ( bivalves1 & has accumulat$ also 9 concretions & cry/all9e gr\ps4 ,su* pyrites is probably ( second>y orig91 or arose f ! r$uc+ action ( decay+ organic matt] on f]r\s sulphate 9 solution 9 ! sea4 ,! oxidation ( iron pyrites 9 %ales gives rise to alum9ium sulphates1 su* z alums4 ,sometimes suffici5t heat is evolv$ dur+ ?is oxidation to set on fire c>bonace\s matt] pres5t 9 ! rock4 ,p9k-purple & gre5 are common col\rs among %ales1 & imply t ! iron is 9 two diff]5t /ates ( oxidation4 ,:5 ! col\r v>ies ?us 9 successive b&s1 we may believe t a climatic *ange promot$ ! =mation ( f]ric salts on ! l& surface :5 ! p9k lay]s 7 be+ =m$1 :ile f]r\s 7less oxidis$7 salts pr$om9at$ :5 ! gre5 p>ticles 7 wa%$ into ! bas94 ,b4 ,smi?#dc sugge/s t ! organic matt] & humic acids :i* are swept d[n 9 times ( flood may tempor>ily prev5t oxidation f occurr+ 9 %all[ lakes & pools4 ,dry seasons w\ld ?us lead to ! deposition ( p9k clays1 :ile wet seasons w\ld furni% gre5 ones4 ,! gre5 col\r 9 %ales is mo/ly due to *lorite or to glauconite4 ,subsequ5t deoxidation has be5 invok$ to acc\nt = ! gre5 col\r ( c]ta9 %ales4 ,organic matt] may h be5 responsible1 & ! gre5 spots 9 purple slates h be5 attribut$ to ! decay ( entomb$ organisms1 ! reaction hav+ spread outw>ds f a c5tre4 ,clays1 ow+ to _! imp]meability1 pres]ve fossils excell5tly1 & ! olde/ %ells & corals 9 :i* ! orig9al aragonite has escap$ conv]sion into calcite occur 9 clays & %ales ( ,mesozoic age 7see p4 #bb74 ,,orig9 ,,( ,,clays ,some?+ has be5 said on ?is matt] 9 ! =ego+ p>agraphs4 ,x is n[ recognis$ t a pure *9a-clay or a pipe-clay1 t is1 a pure kaol9-e>?1 does n arise f ! sift+ ( ! products ( surface-d5udation4 ,! alkali felsp>s decompose z !y lie 9 expos$ lay]s ( granite & gneiss1 b ! kaol9 ?us =m$ "u ! acid action ( atmosph]ic wat]s is relatively small 9 quantity1 & _c escape f its co>s] associates1 su* z undecompos$ felsp> & qu>tz1 until x is c>ri$ away f> f l&4 ,ev5 !n1 z ! records ( ,h4,m4,s4 ,*all5g] %[#dd1 m>9e muds may conta9 m ?an fifty p] c5t4 ( detrital qu>tz-gra9s1 & qu>tz is always ! mo/ abundant m9]al among ! l>g] p>ticles ( ! mud4 ,:]e1 h[ev]1 decomposition ( ! granitoid rock has be5 exceptionally ?or\gh1 kaol9 may be pres5t 9 suffici5t quantity to pr$om9ate ov] o!r mat]ials4 ,! product wa%$ f ! surface !n ga!rs z a :ite clay ev5 9 lakes1 & fur!r artificial wa%+ may extract f x an actual kaol9-e>? or *9a-clay4 ,9 su* cases1 ! rock has become rott$ ?r\gh\t 9 consequ5ce ( subt]ranean action4 ,hydr(luoric acid z well z o!r gases h be5 at "w1 z is %[n by ! second>y m9]als associat$ ) ! kaol92 & ! appe>ance ( :ite p[d]y kaol9 9 unusual abundance on ! surface is due to ! local exposure ( a mass t 0 long ago made ready 9 ! dep?s4 ,! sift+ action1 h[ev]1 ( runn+ wat]s1 & especially ( ! sea ^u a %ore1 ultimately causes clayey matt] to be c>ri$ away into regions :]e x is sl[ly deposit$4 ,! flocculat+ action ( ! salts dissolv$ 9 sea-wat] greatly assi/s ! precipitation ( clay be=e x has rea*$ "s two hundr$ miles f l&4 ,h[ev]1 j z s&/one begets s&/one1 clays or %ales expos$ ^u a coa/ produce new clays close to %ore4 ,! e/u>y ( ! ,?ames & _m slob-l&s s]ve z examples4 ,(f ,brazil1 r$ clays arise#de f ! l>ge quantity ( o*re\s matt] c>ri$ f ! coa/4 ,mod]n gre5 m>9e muds are f\nd to conta9 glauconite1 a silicate common 9 ! ,engli% ,gault clays1 & =m$ by int]actions 9 ! sea itself4 ,mod]n blue muds#df are record$ d[n to #bhjj fa?oms1 & conta9 organic matt] & iron disulphide4 ,mu* has be5 writt5 by ! obs]v]s on ! ,*all5g] & by o!rs on ! r$ clay ( truly abyssal dep?s1 :i* is attribut$ to ! decay ( w9d-borne volcanic du/1 & ( igne\s matt] erupt$ on ! sea-floor1 r ?an to any direct transport by wat] f ! l&4 ,clays may also accumulate on a l&-surface f f9e volcanic a%1 :i* decomposes ?r\gh ! action ( p]colat+ wat]s4 ,,slate ,! relations betwe5 %ale & ,slate are s obvi\s t slate may readily be reg>d$ z a v well-compact$ mud4 ,! clayey mat]ial 9 x1 l t ( muds1 may be ord9>y detritus or ( volcanic orig92 its col\rs repeat ^? ( %ales4 ,its ess5tial "*1 h[ev]1 is ! possession ( a cleavage1 t is1 ( well-develop$ planes ( fissility1 :i* are (t5 incl9$ to ^? ( b$d+4 ,! b$d+ may be indicat$ by b&s ( diff]5t co>s5ess or con/itution1 & ^! may %[ crumpl+ due to pressure t has be5 ex]t$ on ! mass4 ,! cleavage1 h[ev]1 may run "r across ^! b&s1 & ! rock1 z a rule1 splits f> m cleanly along ! cleavage-planes ?an a %ale does along its planes ( b$d+4 ,! e>ly & hi/oric obs]vations on slaty cleavage h be5 excell5tly review$ by ,a4 ,h>k]#dg1 :o also provides an indep5d5t inve/igation4 ,ref]5ce may also be made to a lat] treatise by ,c4 ,k4 ,lei?#dh1 :i* conta9s num]\s illu/rations1 & to a discussion by ,g4 ,w4 ,lamplugh#di4 ,d4 ,%>pe & ,h4 ,c4 ,sorby1 betwe5 #ahdg & #ahec1 develop$ ! !ory t rock-cleavage 0 due to compression 9 a direction p]p5dicul> to ! planes ( cleavage & to expansion along !m4 ,z ,h>k] po9ts out1 x is unlikely t ! expansion balances ! compression4 ,! d5sity ( slate1 ab\t #bg1 is a good indication t ! porosity1 or p]c5tage ( pore-space1 has be5 r$uc$1 :ile ! m9]al *anges1 soon to be ref]r$ to1 are also 9 fav\r ( great] d5sity4 ,c4 ,d>w9#ej laid /ress on ! connexion betwe5 cleavage & ! developm5t ( flaky m9]als1 su* z micas1 along ! cleavage-planes1 ! /ructure ultimately pass+ into t kn[n z foliation 7see p4 #ade74 ,h4 ,c4 ,sorby urg$ t compression br+s platy p>ticles into p>allel positions ?r\gh\t ! mass1 s t ! plates1 :i* may consi/ ( kaol91 mica1 or *lorite1 come to lie ) _! broad surfaces p]p5dicul> to ! direction ( compression4 ,at ! same "t1 any con/itu5ts capable ( de=mation become compress$ 9 ?is direction1 become exp&$ 9 a direction p]p5dicul> to x1 & are !mselves conv]t$ into l5s-l =ms or plates4 ,t4 ,mell>d ,reade & ,p4 ,holl&#ea h emphasis$ ! "p play$ by cry/allisation at ! close ( ! process ( compression4 ,!y urge t ! platy m9]als1 mica & *lorite1 are produc$ dur+ ! alt]ation ( ! rock1 & c spread ) ease 9 directions p]p5dicul> to t ( compression2 !y ?us give rise to slaty cleavage at a late /age 9 ! de=mation ( ! rock4 ,^! au?ors1 x w be se51 h develop$ "o ( ,d>w9's pr9cipal propositions1 z to ! close connexion betwe5 rock-cleavage & foliation1 &1 9 opposition to ,sorby1 consid] ! plat9ess ( ! orig9al con/itu5ts to be ( less importance4 ,9 support ( _! view1 9 reg>d to ! late /age at :i* cleavage is induc$1 x may be not$ t ! cry/als ( pyrite & magnetite t sometimes occur 9 slates & 9 ! alli$ foliat$ s*i/s h develop$ at an e>li] date z knots :i* oppose ! cleavage or ! foliation#eb4 ,d>w9 obs]v$ t m9]al diff]5ces sometimes occur along b&s p>allel ) ! cleavage-planes4 ,9 su* cases1 ! diff]5ce may be l>gely "o ( gra91 %e>+ hav+ brok5 d[n ! m9]als into a f9] /ate along c]ta9 b&s ( movem5t#ec4 ,%e>+ ( ! rock may occur along any ( ! cleavage-planes1 :i* are sup]9duc$ planes ( weakness1 & p>ts ( ! slate ?us slide ov] o!rs1 j z ! m9]al flakes slide ov] "o ano!r 9 ! directions 9 :i* expansion ( ! rock is possible4 ,:]e traces ( ! orig9al /ratification rema91 x is easy to see if rock-%e>+ has occurr$4 ,b$s ( diff]5t composition naturally take on cleavage 9 v diff]5t degrees4 ,s&y lay]s %[ ! compression t has tak5 place by contort+2 b !y cleave v poorly1 & 9 proportion to ! am\nt ( mud pres5t 9 !m4 ,:]e clayey & s&y lay]s alt]nate1 & ! direction ( ! cleavage is oblique to !m1 x is refract$1 z x 71 on pass+ f "o lay] to ! o!r2 x is m highly incl9$ to ! b$d+ 9 ! s&y lay]s & less s 9 ! clayey lay]s4 ,h5ce a cleavage-surface =ms a fold resembl+ ! %ape ( an italic ,s z x trav]ses ea* h>d] b$4 ,h>k]#ed & ,lei?#ee discuss ! cause ( ?is f some:at diff]5t po9ts ( view4 ,x is probable t su* cleavage-planes z develop )9 ! h>d b$ are approximately p]p5dicul> to ! direction 9 :i* ! compressive =ce acts1 because !re is 9 su* b$s little possibility ( lat]al creep ( ! mat]ial along ! b$d+-planes4 ,9 ! s(t] lay]s1 we h to deal1 n only ) a t5d5cy t[>ds ! rotation ( platy p>ticles until _! flat surfaces are p]p5dicul> to ! direction ( pressure1 b also ) a t5d5cy ( ! same p>ticles to fl[ along ! b$d+-planes4 ,! resultant arrangem5t gives rise to a cleavage ne>] to ! b$d+-planes ?an t 9 ! m s&y lay]s4 ,sometimes1 aft] ! cleavage is e/abli%$1 compression folds x1 j z /rata may be fold$4 ,/ill great] compression may oblit]ate x & e/abli% a new cleavage1 & all gradations t[>ds ?is result are traceable4 ,! cleavage lay]s1 aga91 may be wr9kl$ into a s]ies ( %>p folds1 ?ru/ ov] 9 "o direction1 & p>t+ may !n take place along ! ridges ( ^! folds1 :i* furni% a second s]ies ( planes ( weakness 9 ! rock4 ,?is type ( sep>ation has be5 /yl$ a /ra9-slip cleavage1 & by ,lei? a fracture-cleavage1 9 di/9ction f ord9>y or fl[-cleavage4 ,%e>+ may take place along x1 & ! true or fl[ cleavage-planes become ?us brok5 across & fault$4 ,illu/ration3 ,fig4 #i4 ,l&slide ( ,lime/one ov] ,%ale4 ,ne> ,luc-en-,diois1 ,drme1 ,france4 ,! scale is %[n by ! ma9 road pass+ among ! blocks4 ,comm]cial slates %\ld exhibit none ( ^! /ructures t int]f]e ) g5u9e cleavage4 ,an argillace\s rock ( uni=m gra91 compress$ ev5ly ov] a consid]able di/rict1 is requir$ = successful slate-qu>ries4 ,yet all qu>rym5 w admit t ! mat]ial v>ies f po9t to po9t1 & t ! be/ slate runs 9 ve9s4 ,"s ( ! co>s] slates1 ) irregul> surfaces1 & ) spla%es ( col\r1 su* z are provid$ by limonite1 are s\ght aft] = _! picturesque effect2 :ile slates :i* d n split readily en\gh = ro(+ purposes may h _! use = flags1 mantel-%elves1 & billi>d-tables4 ,,argillace\s ,,rocks ,,9 ,,! ,,field ,obvi\sly1 no?+ c be m diff]5t ?an ! features ( a c\ntry made ( clay1 :5 act$ on by d5udation1 & ^? ( "o :]e slate prevails4 ,9 ! =m] case1 l[ r\nd$ hills rise1 )\t any def9ite arrangem5t1 above holl[s :]e ru%es spr+ amid ! grass4 ,! /reams are muddy1 & !y readily cut _! way d[n to base-level1 me&]+ !nce=w>d 9 a clay-alluvium4 ,%ales provide bold] features1 b crumble rapidly :]e ! climate p]mits ( fro/ & ?aw+4 ,!y may be protect$ by m resi/+ rocks1 b provide oozy surfaces und]gr\nd1 ov] :i* ! high] masses may slide disa/r\sly 7,fig4 #i74 ,illu/ration3 ,fig4 #aj4 ,wea!r+ ( ,%ale4 ,granite m\nta9s beh9d4 ,above ,la ,grave1 ,laut>et ,pass1 ,isre1 ,france4 ,%ale-b$s1 :5 uplift$ & fold$1 slip away 9 flakes f "o ano!r1 supply+ v ragg$ & irregul> mat]ial to ! taluses1 & expos+ %imm]+ surfaces :5 damp ) ra9 7,fig4 #aj74 ,among hilly l&s1 ! passes w (t5 be f\nd to be due to b&s ( %ale1 :i* are cut d[n by wea!r+ f> soon] ?an ! rocks on ei!r h&4 ,9 c5tral ,engl&1 ! ,lias %ales1 despite ! pres5ce ( "s lime/ones1 h be5 worn d[n almo/ to a pla91 :]ev] ! ov]ly+ ,middle ,jurassic lime/one has be5 remov$4 ,slates1 ) _! ragg$ edges & resi/ance to ra91 play _! "p 9 wild] m\nta9-sc5]y4 ,fro/-action de/roys !m1 produc+ taluses t slip frequ5tly t[>ds ! valleys2 b ! residual crags assume m s]rat$ =ms1 9 contra/ ) ! smoo? cov]+ ( ! l[] slopes4 ,! cleavage1 :5 /eeply incl9$ to ! horizontal1 promotes ! cutt+ ( gullies d[n ! m\nta9-sides1 & ! int]v5+ ribs ( rock may easily be mi/ak5 = uptilt$ /rata4 ,! entrance to ! ,pass ( ,llanb]is at ,dolbad>n is a f9e picture ( slate-sc5]y4 ,ev5tually1 m\nta9s =m$ ( slate assume hog-back$ & r\nd$ =ms1 b !y /ill1 :]e not*$ by /reamlets1 yield %e] cliffs & picturesque rav9es4 ,,on ,,b\ld]-,,clay ,! mat]ial kn[n z ,b\ld]-,clay pres5ts su* di/9ctive features1 & is s preval5t 9 our isl&s1 t x des]ves a few sep>ate rem>ks4 ,f a coat+ a foot or two 9 ?ickness1 x swells 9 places to a hundr$ feet or m1 & may =m ! important r\nd-back$ hills to :i* ,maxwell ,close res]v$ ! "n ( druml9s4 ,illu/ration3 ,fig4 #aa4 ,b\ld]-,clay1 ,cri*1 ,d]by%ire4 ,x consi/s ess5tially ( mix$ mat]ials1 unsift$ by wat]1 huge b\ld]s ( v>i\s rocks occurr+ side by side ) angul> fragm5ts & pebbles ( all sizes1 set 9 a gr\ndwork ( loamy clay 7,fig4 #aa74 ,s&s & gravels are (t5 associat$ ) ! b\ld]-clay1 & result f ! local wa%+ ( ! mass 9 copi\s floods ( wat]4 ,! blocks are "h on ! :ole m r\nd$1 & ! s&y "p ( ! loam pr$om9ates4 ,blocks ( %ale & lime/one1 & ev5 ( s&/one & qu>tzite1 occurr+ 9 ! b\ld]-clay1 be> ! *>act]i/ic /riations t we n[ recognise z due to glacial action4 ,! s& & small /ones h1 9 fact1 be5 held aga9/ ! l>g] ones by solid ice1 & h cut & groov$ _! surfaces4 ,%ales & s*i/s h gone to pieces & h provid$ ! clayey gr\ndwork4 ,! :ole ( ! mat]ial has be5 at "o "t emb$d$ 9 & mov$ =w>d by glaci]-ice4 ,illu/ration3 ,fig4 #ab4 ,arctic ,glaci] *>g$ ) /ones & clay4 ,side ( ! ,nord5skild ,glaci]1 ,bill5 ,bay1 ,spitsb]g54 ,! top ( ! ice appe>s 9 ! left-h& upp] corn] ( ! picture4 ,?\gh ,l\is ,agassiz develop$ 8 glacial !ory f /udies 9 ,switz]l&1 he possess$ an imag9ation t ran be=e ! k ( 8 "t4 ,swiss glaci]s are n[ s limit$ t !y are ( v little use to u :5 we seek to expla9 ! orig9 ( b\ld]-clay4 ,9 arctic & ant>ctic l&s1 h[ev]1 we meet ) cont95tal glaci]s1 _m miles 9 wid?1 mov+ across l[l&s1 9 virtue ( ! pressure f "s great sn[-dome1 to :i* additions are cont9ually be+ made beh9d !m4 ,ev5 :5 f$ by dim9i%$ sn[-fields1 l ^? 9 ,spitsb]g51 ^! glaci]s dom9ate ! l&scape & =m ! pr9cipal rock-masses ov] hundr$s ( squ>e miles4 ,su* glaci]s ga!r into _! l[] portions all ! loos5$ mat]ial on ! hill-slopes & valley-floors4 ,) ! tools ?us suppli$1 fur!r mat]ial is pluck$ f jo9t$ or fissile rocks z ! mass moves =w>d4 ,freez+ & ?aw+ at ! base ( ! great ice-%eet1 z wat] fl[s "h & !re b5ea? x1 fur!r dis9tegrate ! rocky floor4 ,! broad ice-%eet s9ks 9 a mass ( brok5 rock & sludge at "o po9t1 & at ano!r drags ?is mix$ mat]ial =w>d z an abrad+ ag5t4 ,! l[] half ( su* a glaci]1 or ! :ole ?ickness ( x ne> its front1 :]e surface-melt+ has remov$ ! high] lay]s1 is 9 reality an agglom]ate ( /ones & mud held toge!r by an ice-cem5t 7,fig4 #ab74 ,:5 an epo* ( advance is ov]1 :5 ! ice-%eet /agnates & its froz5 con/itu5t melts away1 x becomes m & m l a b\ld]-clay z "t goes on4 ,true b\ld]-clay !n =ms its surface1 :ile ice rema9s pl5tiful bel[4 ,illu/ration3 ,fig4 #ac4 ,arctic ,glaci] & ,b\ld]-,clay4 ,! ,sef/rm ,glaci]1 ,ekman ,bay1 ,spitsb]g51 9 #aiaj1 ) b\ld]-clay 9 =egr\nd1 m>k$ by kettle-holes1 & deposit$ by an advance ( ! glaci] ov] ,cora ,isl& 9 #ahif4 ,s9ce ! /ony matt] is n ev5ly di/ribut$1 "s p>ts ( ! surface s9k m quickly ?an o!rs1 ?r\gh loss ( a great] portion ( _! =m] bulk4 ,r\ghly circul> pits or kettle-holes appe>1 9 :i* wat] ga!rs4 ,! wat] runn+ f ^! wa%es across a "p ( ! b\ld]-clay1 be>s (f ! mud1 & leaves b&s ( s& & gravel4 ,! clayey portion ?us remov$ may accumulate z a f9e deposit 9 o!r outly+ pools1 & is int]/ratifi$1 :5 ! fl[ ( wat] is tempor>ily increas$1 ) co>s] & m s&y lay]s4 ,ultimately1 ! froz5 wat] ( ! gr\ndwork dra9s away1 & only ! /ones & clay ( ! ice-%eet rema9 ^u ! field4 ,!y =m1 h[ev]1 a v important residue1 wea!r+ 9 /eep cliffs & p9nacles 9 ! dry air ( ! arctic l&s4 ,! b\ld]-clay ?us left %[s a %>ply m>k$ b\nd>y :]e ! edge ( ! /agnat+ ice-%eet lay4 ,x is1 9 fact1 ! surviv+ "p ( ! complex %eet1 & n[ und]goes m\ld+1 l o!r rocks1 by atmosph]ic ag5cies 7,fig4 #ac74 ,_m int]e/+ features ( ! hills call$ druml9s _c be discuss$ "h4 ,_! arrangem5t ) _! long] axes 9 ! direction ( ! movem5t ( ! ice %[s t !y 7 m\ld$ 9 l>ge measure )9 ! ice itself1 & came to light z x melt$ away f above d[nw>ds4 ,!y may be reg>d$ z orig9at+ 9 t\gh & mix$ mat]ials1 ice & /ones & clay1 f ! l[] lay]s ( ! ice-%eet1 :i* became associat$ ) ! pur] upp] ice 9 c]ta9 episodes ( ! fl[4 ,su* m+l+ may occur at an ice-fall1 or :]e %e>+ ov] an ob/acle takes place4 ,9 ! =m] case1 ! upp] ice desc5ds into ! l[] lay]s2 9 ! latt]1 masses f bel[ are pu%$ up into high] levels4 ,z ! =w>d fl[ proce$s1 ! masses repres5t+ ! l[] & /one-fill$ lay]s are treat$ j z eyes ( co>s] mat]ial are treat$ 9 a fluidal lava or 9 a rock de=m$ by metamorphic pressures4 ,! pur] & m pla/ic ice moves pa/ & r\nd !m1 & !y assume an elongat$ =m#ef4 ,:5 f9al /agnation & melt+ h gone on1 ^! masses are /ill sep>at$ f "o ano!r z r\nd$ hills4 ,_! bases h settl$ d[n ^u ! ice-worn surface1 b _! flanks & cre/s reta9 traces ( ! m\ld+ action ( ! pur] portions ( ! complex body /yl$ an ice-%eet4 ,9 rec5t ye>s great int]e/ has be5 ar\s$ by rese>*es on b\ld]-clays ( anci5t date1 especially ^? ( ,p]mo-,c>bonif]\s age#eg4 ,^! compact$ deposits conta9 abundant /riat$ b\ld]s1 & re/ on glaciat$ rock-surfaces1 :i* h a surpris+ly mod]n aspect :5 laid b>e by d5udation4 ,! grey-gre5 ,dwyka ,conglom]ate t is s widely spread ?r\gh\t ,s\? ,africa =ms kopjes on ! bord]s ( ! ,great ,k>roo1 ) spiky cre/s & irregul>ly wea!r$ cliffs2 b its orig9al deposition z a b\ld]-clay has be5 amply v]ifi$4 ,x has n[1 moreov]1 be5 p>allel$ by a v simil> rock discov]$ by ,a4 ,c4 ,coleman 9 ! ,huronian b$s ( ,canada4 ,,*apt] ,v ,,igne\s ,,rocks ,,introduction#eh ,igne\s rocks1 ^? v>i$ masses t h consolidat$ f a /ate ( fusion1 attract$ att5tion 9 ! eighte5? c5tury ?r\gh _! active appe>ance 9 volcanoes4 ,james ,hutton 9 #aghe %[$ t ! cry/all9e granite ( ! ,scotti% highl&s _h be5 made to invade t c\ntry 9 a fluid /ate4 ,m ?an a hundr$ ye>s1 h[ev]1 elaps$ be=e geologi/s on ! cont95t ( ,europe 7 will+ to connect sup]ficial lavas ) ! mat]ials expos$ by d5udation 9 consolidat$ cauldrons ( ! cru/4 ,x is int]e/+ !re=e to note t ,g4 ,p4 ,scrope 9 #ahbe treat$ ( granite1 )\t apology or hesitation1 9 a "w entitl$ ,consid]ations on ,volcanoes4 ,s f> f sep>at+ deep-seat$ f sup]ficial products1 ,scrope wrote ( ! molt5 magma 9 ! cru/ z ! g5]al subt]ranean b$ ( lava4 ,he conceiv$ ?is fundam5tal magma1 ! orig9al or "m-rock1 to be capable ( consolidat+ z ord9>y granite4 ,successive melt+s & physical modifications ( ?is granite gave rise1 9 8 view1 to all ! o!r igne\s rocks4 ,scrope laid no /ress1 h[ev]1 on *emical v>iations )9 ! magma1 b urg$ t ! transitions obs]vable betwe5 diff]5t types ( igne\s mat]ial e/abli%$ a community ( orig94 ,! connexion betwe5 lavas & highly cry/all9e deep-seat$ rocks1 s simply accept$ by ,scrope1 0 work$ out "s fifty ye>s lat] by ,j4 ,w4 ,judd = areas 9 ,hung>y & 9 ! ,inn] ,hebrides4 ,! features display$ 9 ?9 sections "u ! microscope 7 us$ by ,judd1 9 a s]ies ( pap]s1 to sub/antiate 8 views2 b 9 ,france & ,g]many ^! features became ! s\rce ( subtle di/9ctions betwe5 ! igne\s rocks ( ,ca9ozoic & pre-,ca9ozoic days4 ,! lavas1 9 :i* "s glassy matt] c\ld be trac$1 7 said to be typically po/-,cretace\s1 & ess5tially diff]5t f ^? e>li] types 9 :i* glass 0 replac$ by f9ely cry/all9e matt]2 :ile ! co>sely cry/all9e igne\s rocks 7 uni=mly reg>d$ z pre-,ca9ozoic4 ,glassy rocks1 su* z pit*/one1 int]b$d$ contemporane\sly 9 ,p]mian or ,devonian /rata1 7 describ$ z vitre\s porphyries1 :ile ^? kn[n to be ( po/-,cretace\s date might be /yl$ &esites1 tra*ytes1 or rhyolites4 ,luckily common s5se has rec5tly triumph$ 9 ?is matt]1 & ! relative sc>city ( glassy types ( igne\s rocks 9 e>ly geological =mations has be5 recognis$ z due to ! read9ess ) :i* glass und]goes second>y cry/allisation4 ,! discussion has end$ by %[+ t we h no evid5ce ( _w-wide *anges 9 ! types ( mat]ial erupt$ dur+ geological "t4 ,at ! pres5t day1 att5tion has be5 focus$ on ! processes t g on 9 subt]ranean cauldrons1 9 ! hope ( expla9+ ! diff]5ces betwe5 "o type ( extrud$ rock & ano!r4 ,doctr9es ( desc5t h be5 elaborat$1 & "o ( ! mo/ subtle sy/ems ( classification#ei has be5 bas$ ^u *>act]s t ! igne\s rock might h possess$1 _h circum/ances n imp>t$ o!rs to x dur+ ! process ( consolidation4 ,! pr9ciple ( ?is classification is1 h[ev]1 obvi\sly correct1 if we wi% to trace back a rock be>+ c]ta9 *>act]s at ! pres5t day to ! molt5 s\rce f :i* x came4 ,,*>act]s ,,( ,,igne\s ,,rocks ,! *>act]s ( igne\s rocks v>y consid]ably accord+ z !y h consolidat$ "u atmosph]ic pressure only1 or "u t ( sup]9cumb5t rocks4 ,we mu/ rememb] also t subm>9e lavas h to su/a9 a pressure ( an extra atmosph]e = e ?irty feet ( dep?1 or #djj atmosph]es at #bjjj fa?oms1 & t su* rocks h a claim to be reg>d$ z deep-seat$4 ,! gases t igne\s rocks conta91 probably z ess5tial features ( ! molt5 magma1 & at a temp]ature above _! critical po9ts1 escape to a l>ge ext5t ne> or at ! surface ( ! e>?4 ,! bubbles rais$ 9 lava1 :]eby x is r5d]$ scoriace\s1 & ! cl\ds ( vap\r ris+ f cool+ lava-fl[s & f ! ?roat ( a volcano 9 eruption1 are suffici5t evid5ces ( ?is process4 ,! extremely liquid lavas ( ,kilauea 9 ,hawaii1 :i* emit v little vap\r1 are notable z exceptions4 ,9 ! case ( masses t cool und]gr\nd1 ! ret5tion ( gases1 & ultimately ( liquids1 until a v late /age ( consolidation ret>ds cry/allisation until temp]atures are rea*$ l[] ?an ^? at :i* x />ts 9 surface-fl[s4 ,z ,a4 ,h>k] po9ts out#fj1 ! loss ( ^! sub/ances1 by rais+ ! melt+-po9ts 9 ! magma1 may be ! imm$iate cause ( cry/allisation1 q z mu* z any actual cool+4 ,! =mation ( cry/als 9 lavas is rapid1 & ! av]age cry/als are !re=e small1 & (t5 felt$ toge!r 9 a me%1 ! int]/ices ( :i* are fill$ by residual glass4 ,sl[ness ( cool+ is ! really important factor t affects ! size ( cry/als1 t is1 ! co>s5ess ( gra91 9 igne\s rocks4 ,pressure may promote cry/allisation1 by rais+ ! melt+-po9ts ( m9]als2 b1 aft] a c]ta9 maximum effect 9 ?is direction1 x is q possible t an increase ( pressure may actually l[] ! melt+-po9ts1 & cause "o or o!r m9]al to rema9 9 solution 9 ! magma4 ,x is n cle> h[ pressure c affect ! size ( any con/itu5t1 except by br++ ab\t conditions "u :i* x c g on gr[+1 :ile o!r con/itu5ts rema9 9 solution1 or d n gr[ s fa/4 ,su* conditions may arise f ! aid giv5 by pressure to ! ret5tion ( :at ,fr5* geologi/s h call$ ag5ts m9ralisateurs4 ,sev]al famili> m9]als1 = in/ance albite1 or?oclase1 & qu>tz1 require ! pres5ce ( wat] = _! =mation4 ,volatile sub/ances1 n utilis$ 9 ! ultimate product1 no d\bt simil>ly assi/ ! =mation ( _m rock-=m+ m9]als4 ,occasionally1 moreov]1 z 9 ! developm5t ( ! micas & c]ta9 ( ! silicates kn[n z zeolites1 "s proportion ( hydrog5 is reta9$ by m9]als ?us cry/allis+ f ! magma4 ,micas appe> to require ! pres5ce ( fluor9e = _! developm5t4 ,j4 ,p4 ,idd+s#fa1 h[ev]1 lays /ress 9 ?is case on ! *emical activity ( hydrog5 at high temp]atures4 ,igne\s rocks1 unless cool$ ) s+ul> rapidity1 ?us conta9 cry/als ( v>i\s k9ds4 ,9 lavas1 ^! may =m ! globul> aggregates kn[n z sph]ulites#fb1 or may accumulate z a compact gr\nd ( m9ute gra9s & ne$les1 n q resolvable ) ! microscope4 ,9 _m rocks ( slightly co>s] gra91 a compact li?oidal or /ony texture is set up1 :i* ! microscope resolves into an aggregate ( cry/all9e rods or granules4 ,su* compact rocks are (t5 /yl$ felsitic4 ,9 o!r types1 z 9 ord9>y granite1 ! con/itu5t m9]als are easily di/+ui%$ ) ! nak$ eye4 ,! ord] 9 :i* ^! con/itu5ts h develop$ is sometimes cle> f ! inclusion ( "o m9]al 9 ano!r4 ,:5 two sub/ances are dissolv$ 9 "o ano!r1 !re is a c]ta9 proportion betwe5 !m1 v>y+ ) ! sub/ances1 :i* all[s !m to cry/allise at ! same "t1 in/ead ( 9 succession4 ,?is eutectic proportion1 :5 atta9$ by two m9]al sub/ances 9 a magma1 br+s ab\t a complete int]lock+ ( _! cry/als1 z is se5 9 ! qu>tz & alkali-felsp> ( ! rock kn[n z graphic granite4 ,! ord] ( cry/allisation ( m9]als f an ord9>y non-eutectic magma is pr(\ndly affect$ by ! proportions 9 :i* _! con/itu5ts are pres5t 9 ! mass4 ,! m9]als1 :5 !y h sep>at$ out1 are f\nd to be mo/ly silicates4 ,a few oxides1 su* z rutile1 magnetite1 & ilm5ite1 may occur1 ! two latt] be+ especially common :]e iron is an important con/itu5t ( ! rock4 ,b almo/ all igne\s rocks consi/ l>gely ( "o or m species ( felsp>1 silica be+ "h comb9$ ) alum9a1 pota%1 soda1 & lime4 ,free silica may rema91 & sep>ates z qu>tz1 or r>ely z tridymite4 ,pale mica occurs 9 _m rocks ( deep-seat$ orig94 ,9 contra/ ) ^! light-col\r$ m9]als1 iron1 magnesium1 & "p ( ! calcium1 appe> 9 ano!r s]ies ( silicates1 usually d>k 9 col\r1 & ?is s]ies may be broadly /yl$ f]romagnesian4 ,! pyrox5es1 ( :i* augite is ! type1 ! amphiboles1 ( :i* hornbl5de is ! type1 d>k mica 7mo/ly biotite71 & oliv9e1 are ! ord9>y f]romagnesian m9]als4 ,broadly1 !n1 igne\s rocks divide !mselves by texture into 7i7 ^? :i* are completely cry/all9e1 & 9 :i* ! m9]als are di/9ctly visible2 7ii7 ^? :i* are completely cry/all9e1 b 9 :i* ! cry/als are s small z to give rise to a compact li?oidal gr\nd-mass2 & 7iii7 ^? 9 :i* "s glass is pres5t4 ,! ?ird gr\p may appe> li?oidal1 or 9 o!r cases actually glassy1 to ! unaid$ eye4 ,?is mode ( division is ju/ifi$ f a natural hi/ory po9t ( view4 ,! fir/ gr\p includes rocks t h consolidat$ sl[ly und]gr\nd4 ,! second includes rocks cool$ m quickly1 on ! m>g9s ( magma-bas9s1 or z (f%oots f !m1 fill+ cracks 9 ! surr\nd+ rocks1 & produc+ wall-l masses kn[n z dykes4 ,! ?ird gr\p appe>s mo/ly 9 dykes & lava-fl[s4 ,:]e a dyke has intrud$ among heat$ rocks & und]goes no sudd5 *ill+1 x may become co>sely cry/all9e1 ev5 ?\gh comp>atively small4 ,"s dykes exhibit a *ill$ m>g9 ( glass along _! b\nd+ surfaces1 & are none ! less completely cry/all9e at ! c5tre1 :]e cool+ has be5 sl[4 ,no /ructure is peculi> to dyke-rocks1 nor c a class be e/abli%$ = su* rocks on *emical or m9]alogical gr\nds1 ev5 ?\gh a few special types ( igne\s rock may at pres5t be kn[n only among ^! m9or intrusive bodies4 ,illu/ration3 ,fig4 #ad4 ,side ( a ,volcanic ,cone4 ,a%-lay] ( #aijf on ! we/ flank ( ,vesuvius4 ,cliffs ( ! explod$ crat] ( ,monte ,somma beh9d4 ,! f9e-gra9$ lay]s ( volcanic du/1 commonly spok5 ( z a%1 & ! co>s] tuffs1 9 :i* lumps ( scoriace\s lava are cle>ly visible1 bridge ! gap betwe5 s$im5t>y & igne\s rocks4 ,! du/1 dur+ a great eruption1 is di/ribut$ by w9d ov] hundr$s ( squ>e miles ( c\ntry4 ,! tuffs1 deposit$ ne>] ! orifice ( ! volcano1 v>y 9 co>s5ess f day to day1 & exhibit m>k$ /ratification4 ,a%-b$s & tuffs may be laid out 9 lakes or 9 ! sea1 & _! lay]s may !n include organic rema9s4 ,waves may r\nd _! p>ticles on ! %ore1 & may sift !m till only a co>se volcanic s& rema9s4 ,aft] an eruption1 ! newly deposit$ a% & tuff usually =m obvi\s lay]s on ! surface ( ! c\ntry4 ,l&slips on ! side ( ! volcanic cone may reveal sections ( ! new coat+ & ( previ\sly /ratifi$ mat]ial 7,fig4 #ad74 ,9 c]ta9 di/ricts1 s$im5t>y & o!r rocks torn (f f bel[ =m a l>ge "p ( ! fragm5tal deposits ( volcanic action4 ,! *>act]i/ic volcanic cone is itself due to ! great] accumulation ( tuffs & a%es ne> ! v5t 7,fig4 #ae74 ,! loose tuffs =m$ ( scori all[ wat] to p]colate easily ?r\gh !m1 & a cone ( fairly co>se mat]ial resi/s ! wea!r well4 ,! rem>kable fre%ness ( ! ext9ct c9d]-cones ( ,auv]gne 0 ?us long ago expla9$ by ,lyell4 ,surfaces ( a%1 on ! o!r h&1 are easily wa%$ d[n by ra9 9 ! =m ( dang]\s mud-fl[s1 :i* spread across ! l[l&s1 & give rise to compact clays1 %r9k+ z !y dry4 ,illu/ration3 ,fig4 #ae4 ,tuff-,cone ) ,tuff-,b$s at ! base4 ,puy de la ,va*e1 ,puy-de-,dme1 ,france4 ,lava-fl[s are masses ( molt5 rock t h well$ out f ! v5t1 )\t be+ torn to pieces by ! explosion ( ! gases t !y conta9$4 ,! rapidity ( _! fl[ dep5ds on _! *emical composition1 on ! am\nt ( gases pres5t1 & on ! temp]ature at :i* !y are extrud$4 ,! m highly silice\s lavas1 = a giv5 temp]ature1 are m visc\s ?an ^? t[>ds ! basaltic end ( ! s]ies1 :i* conta9 only ab\t #dh p] c5t4 ( silica4 ,a lava ( consid]able fluidity w consolidate 9 some:at ?9 %eets ) smoo? & ropy surfaces4 ,a less fluid type w become m>k$ly scoriace\s1 :]e ! vap\rs endeav\r to escape f x2 ! rugg$ cru/ =m$ on its upp] cool+ surface w be brok5 up by ! cont9u$ movem5t ( ! m liquid mass bel[1 & ! blocks ?us =m$ may become roll$ ov] ! advanc+ front ( ! fl[ & entomb$ 9 ! portion t has n yet consolidat$4 ,! surface ( ord9>y lava-fl[s rema9s r\gh = c5turies1 & only sl[ly crumbles d[n be=e wea!r+ to =m a soil4 ,:ile tuff-b$s provide light & f]tile l&s1 ! lava-/reams rema9 m>k$ out among !m1 z s9u\s b&s ( rock1 giv5 ov] to an irregul> gr[? ( woodl&4 ,by repeat$ outfl[s1 lavas t5d to fill up ! int]spaces betwe5 ! e>li] /reams1 j z ^! h fill$ up ! holl[s 9 ! c\ntry ov] :i* !y spread4 ,a uni=m surface ?us arises1 & lava-pla9s ev5tually bury a v>i$ l& ( hill & dale4 ,:]e a numb] ( small v5ts h op5$1 p]haps along p>allel fissures 9 ! e>?1 ! flood+ ( ! c\ntry ) igne\s rock may lead to an appe>ance ( /ratification 9 masses ext5d+ ov] hundr$s ( squ>e miles4 ,sections 9 ! igne\s s]ies1 h[ev]1 %[ t ! individual fl[s dove-tail into & ov]lap "o ano!r1 m rapidly ?an is ! case ) ! l5ticul> masses t con/itute an ord9>y s$im5t>y s]ies4 ,aft] ! con/itu5ts ( ! lava h begun to cry/allise1 & :5 ! rock may be consid]$ solid1 cracks due to contraction are set up4 ,! upp] "p ( ! fl[1 radiat+ its heat & p>t+ ) its gases into ! air above1 solidifies comp>atively rapidly1 & cracks arise )\t mu* regul>ity4 ,n[ & !n1 column> /ructure1 l t ( dri$ />*1 appe>s on a small scale1 ! columns />t+ f v>i\s oblique surfaces ( cool+1 & ly+ 9 consequ5ce 9 v>i\s directions 9 ! rock4 ,j4 ,p4 ,idd+s %[s t curvature ( ! columns w result if "o portion ( ! surface loses heat m rapidly ?an ano!r4 ,z ! contraction-cracks b\nd+ ! columns spread inw>ds1 ! lay] rea*$ by !m at any "t 9 ! lava w be f>!r 9 f a "p ( ! surface :]e cool+ is rapid ?an x w be f a "p :]e x is sl[4 ,h5ce ! lay] 9 ! lava :]e contractional /resses are produc+ cracks1 i4e4 ! lay] rea*$ at any "t by ! inn] ends ( ! contraction-columns1 w be a curv$ "o1 & its curvature w increase z x occupies positions m & m remov$ f ! surface ( ! lava-fl[4 ,! axes ( ! contraction-columns1 z !y spread1 are p]p5dicul> to ?is lay]1 & ! columns w ?us curve z _! developm5t proce$s4 ,! base ( a massive lava-fl[1 h[ev]1 cools "u mu* m uni=m conditions1 & ! columns1 /ret*+ upw>ds f ! gr\nd & produc$ by sl[ contraction1 give rise to ! regul> prismatic /ructures long ago kn[n z giants' causeways4 ,! orig9al ,giant's ,causeway 9 ! c\nty ( ,antrim is ! l[] "p ( a basaltic fl[1 expos$ by d5udation on ! %ore4 ,f+al's ,cave 9 ,/affa owes its t\gh compact ro( to ! pres]vation ( t portion ( ! fl[ :i* cool$ d[nw>ds f ! upp] surface4 ,g4 ,p4 ,scrope#fc long ago obs]v$ ?is dual /ructure 9 column> lavas4 ,! columns1 or ! m irregul> jo9t-blocks t sometimes repres5t !m1 are (t5 subdivid$ by fur!r contraction into sph]oids1 ! coats ( :i* peel (f1 z ! rock wea!rs1 l ^? ( an onion4 ,! curv$ cross-jo9ts ( massive columns1 n[ convex upw>ds1 n[ concave1 repres5t ! same t5d5cy t[>ds globul> contraction4 ,a lava-fl[ is sometimes divid$ into l>ge rudely sph]oidal masses1 :i* fit into "o ano!r1 & :i* %[ signs ( m rapid cool+ on _! surfaces4 ,^! 7 p>ticul>ly obs]v$ on ! m\nta9s ne> ,mont ,g5vre by ,cole & ,gregory#fd1 :o comp>$ ! =ms to pill[s or s(t cu%ions press$ ^u & aga9/ "o ano!r4 ,x 0 sugge/$ t ^! =ms 7 produc$ by ! see?+ ( viscid lavas1 masses be+ heav$ up & fall+ ov]1 & ! out] lay]s hav+ "t to cool 9 a glassy /ate be=e !y 7 de=m$ by contact ) o!rs4 ,?is pill[-/ructure has be5 widely recognis$1 & ,j4 ,j4 ,h4 ,teall has rem>k$ h[ (t5 pill[-lavas are associat$ ) radiol>ian *]ts4 ,he reg>d$ !m1 !re=e1 z ( subm>9e orig94 ,sir ,a4 ,geikie#fe1 moreov]1 /at$ t ! sph]oidal sack-l /ructure 0 produc$ by ! fl[ ( su* lavas into wat] or wat]y silt4 ,?is acute sugge/ion has n[ be5 v]ifi$ by ,tempe/ ,&]son#ff1 :o has obs]v$ 9 ,samoa ! *ill+ ( ! lobes ( lava1 z !y are ?ru/ (f into ! sea & wa%$ ov] by ! waves4 ,h4 ,dewey & ,j4 ,s4 ,flett#fg h po9t$ out t pill[-/ructure commonly occurs 9 lavas 9 :i* !re has be5 a conv]sion ( lime soda felsp>s into albite1 a *ange frequ5t 9 a s]ies ( rocks :i* !y call ! spilitic suite4 ,! importation ( soda is attribut$ to vap\rs ent]+ soon aft] ! consolidation ( ! rock1 & x is urg$ t any excess ( sodium silicate mu/ h escap$ into ! sea-wat] 9 :i* ! pill[-lavas 7 produc$4 ,h5ce radiol>ia w fl\ri% 9 ! neighb\rhood 7presum+ t a decomposition ( ! silicate c be br\ght ab\t71 & _! rema9s w 9 "t =m fl9t 9 ! holl[s ( ! lavas4 ,! pap] quot$ conta9s num]\s ref]5ces to previ\s "w1 & is a sugge/ive example ( h[ petrographic /udy may g h& 9 h& ) ! appreciation ( rocks f a natural hi/ory po9t ( view4 ,x is only *>act]i/ic ( ! subject ( petrology t ,g4 ,/e9mann#fh has ) equal +5uity expla9$ ! relations betwe5 radiol>ia & spilitic lavas by rem9d+ u t gravity-det]m9ations %[ an excess ( basic mat]ial "u ! oceans & ( light] mat]ial1 ri* 9 silica1 "u cont95tal l&4 ,h5ce1 :5 deep-sea deposits are crumpl$ by e>?-movem5ts1 basic types ( rock1 graduat+ ev5 into s]p5t9e1 become associat$ ) radiol>ian *]t1 p>tly z extrud$ lavas1 b usually z intrusive %eets inject$ at ! epo* ( m\nta9-build+4 ,! *>act]s ( igne\s rocks 9 dykes1 t is1 ( ^? types t h consolidat$ 9 fissures1 resemble 9 _m respects ! *>act]s ( lava-fl[s4 ,*ill+ be+ usually equal on bo? surfaces1 glassy or compact types ( rock occur on bo? sides1 & ! dyke is1 z previ\sly obs]v$1 m cry/all9e 9 ! c5tre4 ,column> /ructures arise f bo? surfaces1 ! dyke also %r9k+ p>allel to its m>g9s4 ,9 ! out] lay]s s =m$1 ! columns are small1 & !y increase 9 diamet] ne>] ! c5tre4 ,9 small dykes & ve9s1 ! columns may run cont9u\sly f side to side2 9 l>g] ones1 !y meet along a c5tral surface1 :i* =ms1 on wea!r+1 a plane ( weakness 9 ! rock4 ,dykes may ?us become worn away1 decay spread+ f ! c5tral region1 & leav+ ! m resi/+ & m glassy portions cl++ to ! b\nd+ walls4 ,:]e1 h[ev]1 ! surr\nd+ rocks are m easily worn away ?an ! igne\s invad]1 z v (t5 happ5s1 ! dykes /& out on ! surface z great ribs & walls4 ,! rocks cool$ 9 ! deep-seat$ cauldrons1 "u :at are /yl$ plutonic conditions1 h p>t$ ) _! gases s sl[ly t !y d n %[ scoriace\s /ructure4 ,!y may become v co>sely cry/all9e1 l _m ( ! ,sc&9avian granites2 m9]als1 moreov]1 may be produc$ :i* are un/able or difficult to =m ne>] ! surface4 ,cry/als develop$ 9 plutonic surr\nd+s become c>ri$ =w>d :5 ! p>tially consolidat$ mass is press$ up to a volcanic orifice1 & may und]go resorption on ! way4 ,_m1 h[ev]1 escape1 & imp>t a porphyritic /ructure to lavas4 ,! deep-seat$ rock1 f causes t promote ! gr[? ( "o m9]al & ! ret5tion ( ano!r 9 solution1 may also become porphyritic 9 situ1 small] cry/als1 or ev5 a eutectic int]gr[?1 f9ally fill+ 9 ! gr\nd4 ,! viscidity ( igne\s rocks may cause any ( ! types to %[ a fluidal /ructure4 ,con/itu5ts already =m$ become dragg$ along 9 p>allel s]ies z ! mass moves =w>d4 ,sometimes a gr\p ( sph]ulites1 or a knot ( felsitic matt] caus$ by ! d5se gr[? ( embryo-cry/als1 is /ret*$ out into a %eet1 & on fractur$ surfaces a b&$ /ructure *>act]ises ! mass4 ,^! b&$ rocks record1 9 _! crumpl$ & obvi\sly fluidal lay]s1 ! =m]ly molt5 condition ( ! mass4 ,ev5 completely cry/all9e rocks may %[ p>allel arrangem5t ( _! m9]als1 ow+ to fl[ dur+ ! la/ /ages ( consolidation1 or to pressure f ! walls ( ! cauldron1 influ5c+ ! positions tak5 up by cry/als t possess a rod-l or platy =m4 ,illu/ration3 ,fig4 #af4 ,granite invad+ ,mica-,s*i/4 ,clifton1 ne> ,cape ,t[n4 ,adjac5t sections 7 /udi$ by ,*>les ,d>w9 7see p4 #aef74 ,! conspicu\sly b&$ /ructures 9 "s cry/all9e rocks t are (t5 gr\p$ ) ! metamorphic gneisses may1 h[ev]1 be be/ expla9$ by _! composite orig91 & ! hi/ory ( ! /ructure is easily det]m9able 9 ! field4 ,a common case arises :]e a granite magma1 p]haps already be>+ cry/als1 is intrud$1 "u pressure op]at+ f a di/ance1 into a well-b$d$ s]ies ( s$im5t>y rocks4 ,! s$im5ts op5 up l ! leaves ( a book & admit ! invad] along _! planes ( /ratification4 ,ev5 lime/one may ?us become int]lam9at$ ) an igne\s rock1 j z basalt has be5 kn[n to sep>ate ! annual r+s ( trees involv$ 9 x4 ,?is intimate admixture p]mits ( ext5sive m9]al *anges1 & ! two types ( rock1 probably v diff]5t 9 geological age1 become weld$ toge!r into a composite gneiss1 bo? memb]s ( :i* h influ5c$ "o ano!r by contact-metamorphism1 (t5 across a wide /ret* ( c\ntry 7,fig4 #af74 ,intrusive igne\s rocks 9 ! field w1 h[ev]1 ord9>ily prove _! "* by cutt+ some:]e across ! preval5t /ructure ( ! di/rict4 ,:5 ! mat]ials t else:]e =m dykes p5etrate betwe5 /rata = consid]able di/ances z intrusive %eets1 !y may yet be trac$ to "s po9t :]e !y h made use ( a crack across ! b$d+4 ,! necks or plugs ( old volcanic c5tres sometimes seem to occupy orifices drill$1 or r %att]$1 by explosion "r ?r\gh ! ov]ly+ ob/acles4 ,! approximately circul> necks 9 ,s\? ,africa1 fill$ by brecciat$ masses ( s]p5t9\s rock1 are notable examples4 ,! und]gr\nd cauldrons !mselves1 :5 br\ght to light by d5udation1 are repres5t$ by regions ( cry/all9e rock1 :i* may h v>i\s relations to _! surr\nd+s4 ,we may trace1 9 e case1 ^u _! m>g9s ! ramify+ ve9s t fir/ prov$ to ,james ,hutton t granite 0 y\ng] ?an ! rocks among :i* x lay4 ,b ! portion expos$ may be m]ely ! top ( a huge body or ba?olite ( igne\s matt]1 /ret*+ f> d[n into ! cru/2 or x may be "p ( a localis$ knot1 :i* fill$ up "s cavity provid$ = x by e>?-movem5t1 ooz+ 9 /ep by /ep z room 0 made = its advance4 ,9 ! latt] case1 x 0 orig9ally b\nd$ above by "s s]ies ( /rata :i* 0 ar*$ up z a dome or z an anticl9e4 ,or possibly /rata h be5 mov$ ap>t f "o ano!r1 ! upp] ones slid+ ov] ! l[] ones & at ! same "t bulg+ upw>ds1 s z to leave a cavity ( r\ghly hemisph]ical =m4 ,su* a space1 all[+ relief f pressure1 w be occupi$ by igne\s rock1 :i* may or may n h a direct root ?r\gh ! /ratum und]nea? x4 ,! igne\s mass may 9 su* cases be m]ely an expansion ( a l>ge intrusive %eet4 ,x s5ds (f ve9s into ! ro( above1 & c only be di/+ui%$ f a ba?olite by ! pres5ce ( /ratifi$ rock b5ea? x4 ,occurr5ces ( ?is k9d 7 fir/ describ$ 9 ! ,h5ry ,m\nta9s ( ,utah by ,g4 ,k4 ,gilb]t1 :o gave !m ! "n ( /one-ci/]ns or laccoli?s1 a ^w n[ commonly writt5 laccolites4 ,x may be que/ion$ if ! expansion ( ! gases 9 ! intrud+ igne\s rock is suffici5t 9 itself to =m ! laccolitic dome4 ,! igne\s rock has probably be5 press$ into position by ! =ces t produc$ ! e>?-movem5ts4 ,9 _m cases1 ba?olites seem to h work$ _! way upw>ds )\t any relation to e>?-movem5ts 9 ! di/rict4 ,! processes by :i* !y come into place among o!r rocks are wor?y ( sep>ate consid]ation4 ,,! ,,intrusion ,,( ,,l>ge ,,bodies ,,( ,,igne\s ,,rock ,att5tion has be5 already call$ to ! composite gneisses =m$ by ! intrusion ( an igne\s magma betwe5 ! leaves1 z x 71 ( s$im5ts4 ,su* occurr5ces are (t5 se5 on ! m>g9s ( ba?olites or ( any k9d ( igne\s dome1 & !y no d\bt repres5t ! pick+ (f ( lay] aft] lay] f ! walls surr\nd+ ! intrusive mass4 ,if ^! lay]s c become absorb$ into ! igne\s rock1 ! cre/ ( ! dome c advance1 & ! dome itself c wid51 s long z suffici5t heat is suppli$ to x f bel[4 ,space is f\nd = ! intrusive mass at ! exp5se ( ! m>g9al rocks2 b x is obvi\s t ! portions absorb$ m]ely add to ! bulk ( ! igne\s mat]ial4 ,! composition ( ! latt] mu/ also und]go modification4 ,its great size1 rea*+ z x does f> d[n into ! cru/1 9 comp>ison ) ! quantity ( matt] absorb$ 9 ! upp] regions1 may r5d] su* modification v difficult to trace beyond ! late/ zone ( contact4 ,petrologi/s diff] v widely z to ! ext5t to :i* igne\s masses assume _! place 9 ! upp] regions ( ! cru/ by processes ( /op+1 absorption1 & assimilation4 ,! /atem5t1 h[ev]1 9 a rec5t "w t ! assimilation hypo!sis is /ill support$ by "s ,fr5* geologi/s is calculat$ to surprise ^? :o recognise ! tr5d ( mod]n op9ion bo? 9 ,am]ica & on ! cont95t ( ,europe4 ,f> f ! views ( ,a4 ,mi*el ,lvy1 ,c4 ,b>rois1 & ,a4 ,lacroix1 surviv+ z an expression ( national p]v]sity1 !y h be5 support$ to a rem>kable degree by ! obs]vations ( ,s$]holm 9 ,f9l&1 ( ,lepsius & ,h4 ,cr$n] 9 ,saxony1 ( ,a4 ,lawson & ,f4 ,d4 ,adams 9 ,nor? ,am]ica1 & by ! c>eful reason+ ( ,c4 ,doelt]#fi bas$ l>gely on 8 own exp]im5tal "w4 ,a4 ,h>k]#gj & ,j4 ,p4 ,idd+s#ga h argu$ t assimilation is m]ely a local ph5om5on1 ( little importance 9 ! !ory ( igne\s intrusion4 ,w4 ,c4 ,brgg]#gb1 h[ev]1 :o /rongly supports ! laccolitic view = ! ,*ri/iania di/rict1 expresses himself ) f> m caution1 & leaves ! way cle> = conclusions z to absorption & m+l+ ( molt5 products 9 ! l[] regions ( ! cru/4 ,doelt] lays /ress on ! influ5ce ( high temp]ature1 & especially ( ! highly heat$ gases 9 ! igne\s rock1 9 promot+ corrosion ( ! cauldron-walls4 ,he attributes great] p[] ( corrosion to ! magmas ri* 9 silica1 & agrees ) ,r4 ,a4 ,daly t ! rapidly mov+ basic magmas rea* ! upp] lay]s ( ! cru/ 9 a condition ( comp>ative purity4 ,daly#gc may be look$ on z an extremi/ 9 ?is matt]2 b x is h>d = ^? :o h /udi$ regions :]e ! deep-seat$ cauldrons h be5 cut across by d5udation to avoid v l>ge views ( igne\s absorption4 ,! contact-zones betwe5 ! igne\s mass & ! surr\nd+ rocks are (t5 se5 m]ely 9 cross-section on ! flanks ( a ba?olite or laccolite4 ,9 ! areas ( ,ar*an rocks1 on ! o!r h&1 :]e prolong$ d5udation has expos$ ! zones ( repeat$ int]action ov] hundr$s ( squ>e miles on an approximately horizontal surface1 "o may =m "s idea ( ! processes t are /ill effective 9 ! dep?s4 ,g4 ,v4 ,hawes#gd1 9 #ahha1 recognis$ ! importance ( ! process kn[n by ! m9+ t]m ( /op+1 z a means :]eby igne\s rocks "w _! way upw>d 9 ! cru/4 ,cracks 9 ! ov]ly+ ro( are ent]$ by ! magma1 blocks are w$g$ (f1 & ^! are ultimately absorb$ 9 ! molt5 mass4 ,9 ?is matt] ,hawes /&s z a pione]4 ,z ! viscosity ( ! magma increases dur+ cool+1 ! blocks la/ deta*$ may rema9 emb$d$ 9 ! m>g9al zone4 ,! rem>kable purity ( ?is zone1 h[ev]1 9 _m cases has rais$ an obvi\s difficulty2 b x has be5 po9t$ out#ge t ! modifi$ m>g9al & composite rock may cont9u\sly s9k d[n into ! dep?s1 aid$ by any ( ! causes t promote magmatic diff]5tiation1 :ile a fairly pure magma1 almo/ ( ! orig9al composition1 is left on ! cre/ ( ! advanc+ dome4 ,r4 ,a4 ,daly#gf has develop$ ! /op+ !ory ) consid]able boldness4 ,! areas mo/ likely to c>ry conviction to ^? :o d\bt t igne\s masses c be intrud$ at ! exp5se ( _! surr\nd+s are ^? :]e b&$ gneisses h aris5 on a regional scale 7see p4 #afj74 ,,! ,,range ,,( ,,composition ,,9 ,,igne\s ,,rocks ,! broad division ( igne\s rocks into ^? ( light col\r & ( l[ specific gravity on ! "o h& & ^? t are d>k & heavy on ! o!r is a v natural "o1 & ,buns5 & ,duro*] insi/$ t two magmas 7 fundam5tal 9 ! cru/4 ,9 "o ( ^!1 ! acid magma1 :i* gives rise to granites & rhyolites1 silica =m$ ab\t #gj p] c5t4 by weight ( ! ultimate rocks2 9 ! o!r1 x =m$ ab\t #ej p] c5t41 & ! products are basic diorites1 gabbros1 & basalts#gg4 ,! =m] gr\p ( rocks is ri* 9 alkalies1 ! latt]1 ! basic gr\p1 9 calcium1 magnesium1 & iron4 ,! mixture ( ^! m extreme types ( magma 0 held to give rise to :at are n[ call$ int]m$iate rocks4 ,two o!r views are ( c\rse possible4 ,if ! composition ( ! globe 0 orig9ally uni=m1 ! two magmas mu/ h aris5 by sep>ation f "o ( int]m$iate nature4 ,h5ce1 9 any cauldron 9 ! cru/1 9 place ( "o ( two magmas1 an int]m$iate magma may be presum$ to exi/1 & to split up1 f v>i\s causes1 into a numb] ( p>ts :i* are sep>ately erupt$ at ! surface4 ,*>les ,d>w9's#gh rem>ks z to ! s9k+ ( cry/als 9 a cool+ magma1 & ! consequ5t production ( a tra*ytic & basaltic type 9 ! same cauldron1 l$ ! way to a g5]al acceptance ( ! !ory ( magmatic diff]5tiation 9 laccolites & ba?olites4 ,w4 ,c4 ,brgg]'s#gi brilliant explanation ( ! v>iation & succession ( types ( igne\s rock 9 ! ,*ri/iania di/rict has _h a pr(\nd influ5ce on work]s 9 o!r fields1 & has p]haps direct$ att5tion away f ! p>allel possibilities ( diff]5tiation by assimilation4 ,! assimilation !ory provides ! second possible view above ref]r$ to4 ,a magma may be modifi$ by ! rocks into :i* x intrudes1 s t a basic fluid may become *>g$ ) silica f a s&/one1 ! product cry/allis+ z a granite2 :ile an acid fluid may become s *>g$ ) lime/one t diorite ultimately results4 ,a4 ,h>k]#hj has discuss$ bo? !ories cle>ly1 ) a /rong lean+ to ! acceptance ( magmatic diff]5tiation 9 ! cauldron z ! only important cause ( v>iation4 ,r4 ,a4 ,daly1 on ! o!r h&1 goes at lea/ z f> z ,lacroix 9 ,france 9 support+ ! !ory ( assimilation4 ,= him1 ! primitive igne\s magma is already basic1 & basalts are !re=e ! preval5t type ( igne\s rock4 ,!y rea* u1 moreov]1 f consid]able dep?s4 ,! acid rocks are =m$ by amalgamation ( ?is magma ) silice\s mat]ial ly+ ne>] ! e>?'s surface4 ,igne\s rocks exceptionally ri* 9 alkalies1 ! s-call$ alkal9e s]ies1 result f ! absorption ( lime/one 9 ! magma2 d5s] lime-be>+ silicates are ?us =m$1 :i* s9k by gravitation1 leav+ a light] magma above 9 :i* soda has become conc5trat$4 ,c>bon dioxide lib]at$ f ! lime/one also plays a "p 9 c>ry+ up ! alkalies t might o!rwise rema9 9 a l[] portion#ha4 ,e4 ,h4 ,l4 ,s*w>z#hb ext5ds ,daly's views ) an almo/ romantic fulness4 ,he holds1 ) ,*amb]l91 t ! primitive globe result$ f ! aggregation ( basic meteoritic mat]ial4 ,! m silice\s cru/ arose f ! )drawal ( magnesium & iron into ! dep?s by long-cont9u$ processes ( lea*+ & gravitation4 ,! melt+ ( ?is cru/ produces ! acid igne\s rocks4 ,igne\s cauldrons orig9ate 9 ! heat due to fault+1 or to crumpl+1 or ev5 to ! impact ( gigantic meteorites4 ,:5 a molt5 magma is locally e/abli%$1 v>iation occurs 9 x by assimilation ( diff]5t types ( mat]ial r\nd x4 ,! balance ( judgm5t z to diff]5tiation & assimilation1 :i* %\ld be reg>d$ z p>allel probabilities r ?an z rival propositions1 is admirably held by ,c4 ,doelt]#hc1 ^: *apt]s on ?is matt] c be appreciat$ by all geologi/s4 ,x is ( c\rse possible t diff]5tiation ( type1 f v>i\s causes1 has already proce$$ s f> 9 ! e>?'s cru/ z to produce notewor?y contra/s 9 ! rocks erupt$ 9 diff]5t areas4 ,! int]ior ( our globe1 on ,*amb]l9's planetesimal hypo!sis1 ne$ n h be5 uni=m 9 con/itution1 ei!r at ! outset or at any subsequ5t "t4 ,j4 ,w4 ,judd#hd has call$ att5tion to ! exi/5ce ( petrographical prov9ces1 a conception t has be5 v fruitful 9 results4 ,^! prov9ces h be5 gr\p$ by ,h>k]#he 9 two bran*es1 *>act]is$ respectively by rocks ri* 9 alkalies & by rocks ri* 9 lime4 ,! =m] bran* appe>s to be associat$ ) ! movem5ts ( fault+ & block-/ructure1 r ?an ( crumpl+1 t h produc$ ,e4 ,suess's ,atlantic type ( coa/4 ,! rocks ri* 9 lime1 on ! o!r h&1 are said to be *>act]i/ic ( areas t h be5 fold$ l ! c\ntries bord]+ ! ,pacific4 ,! names ,atlantic & ,pacific h consequ5tly be5 giv5 to ! two bran*es1 b ^! t]ms seem too geographical 9 _! sugge/ion4 ,dewey & ,flett#hf h put =w>d a ?ird type ( magma1 giv+ rise especially to albite z a prim>y or second>y con/itu5t1 & *>act]is$ by ! production ( pill[-lavas4 ,?is type is held to be associat$ ) areas t h /eadily subsid$1 )\t mu* fold+4 ,g4 ,/e9mann#hg1 h[ev]1 has connect$ ! spilites & ophiolitic rocks ) regions ( int5se ov]-fold+4 ,s f>1 !re are _m cases :]e x is difficult to assign a petrographic prov9ce to "o or o!r ( ^! bran*es1 & ! sy/em seems to dem& m simplicity )9 ! prov9ces ?an nature is prep>$ to yield4 ,:atev] ! causes ( v>iation1 x is necess>y to m>k out by names c]ta9 k9ds ( igne\s mat]ial1 & x is g5]ally accept$ t ! types ?us set up are be/ bas$ on *emical composition4 ,at ! same "t1 ! m9]als pres5t 9 ! rock1 & also its /ructure1 record c]ta9 phases ( its hi/ory1 & des]ve an important place 9 any sy/em ( classification4 ,! natural hi/ory ( an igne\s rock is conc]n$ ) its mode ( occurr5ce1 & no isolat$ specim5 c satisfy ! geological inve/igator4 ,9 ! field1 ! porphyritic cry/als1 :i* h an important influ5ce on ! total *emical composition1 may be f\nd to be /rang]s to ! magma1 & to h be5 d]iv$ f "s mass imp]fectly absorb$4 ,! d>k flecks & pat*es 9 a granitoid rock1 s (t5 ascrib$1 some:at my/]i\sly1 to local segregation 9 ! magma1 aga9 & aga9 prove to be metamorphos$ & m9utely inject$ fragm5ts ( =eign rocks#hh4 ,none ! less1 a broad classification is possible on *emical gr\nds1 & ! acid1 int]m$iate1 basic1 & ultrabasic gr\p+ adopt$ by ,judd has be5 f\nd ( great conv5i5ce4 ,among acid rocks we h granite z ! co>sely cry/all9e type1 ) potassium felsp>s preval5t & ! excess ( silica manife/ z qu>tz4 ,! f9] gra9$ & sometimes compact types are ! eurites1 qu>tz-felsites1 or qu>tz-porphyries4 ,:5 ! rock conta9s m or less residual glass1 we h :at are n[ kn[n z rhyolites1 ( :i* ord9>y obsidian is ! mo/ glassy repres5tative4 ,! opposite types1 ^? ( ! basic gr\p1 include1 at ! co>sely cry/all9e end1 gabbro & basic diorite2 ! f9ely cry/all9e =ms are /yl$ dol]ites1 & ^? ) a trace ( glass1 or at any rate v f9e-gra9$ & compact1 are basalts4 ,glassy types are naturally r>e 9 ?is gr\p1 ow+ to ! unsuitable *emical composition4 ,betwe5 granite & gabbro lie v>i\s rocks ( int]m$iate composition1 "s ( !m ri* 9 soda r ?an 9 pota%4 ,sy5ite1 granodiorite1 & ! diorites ) a preval5ce ( soda ov] lime1 are co>sely cry/all9e types4 ,compact types ( ^! ( c\rse occur4 ,x w be suffici5t1 h[ev]1 "h to "n ! =ms ) traces ( residual glass1 :i* range f tra*yte1 ! type ri* 9 pota%1 to &esite1 :i* connects !m ) basalt1 9 a s]ies :]e lime ultimately pr$om9ates ov] soda4 ,9 ! ultrabasic gr\p are a numb] ( exceptional types4 ,oliv9e (t5 becomes an important con/itu5t1 & ! rocks !n decompose into ! s(t gre5 or r$di% masses kn[n z s]p5t9e--or1 m prop]ly1 s]p5t9e-rock4 ,igne\s rocks1 ow+ to _! range ( m9]al composition & ( /ructure1 comb9$ ) _! g5]al h>dness1 l5d !mselves to v>i\s economic purposes4 ,:ile ! granites1 resi/+ atmosph]ic attack admirably 9 a poli%$ /ate1 provide our h&some/ build+-/ones1 dol]ites & f9e-gra9$ diorites1 :i* owe _! t\ghness l>gely to ! int]lock$ relations ( _! con/itu5t m9]als1 s]ve z our mo/ satisfactory road-metals4 ,,! ,,sc5]y ,,( ,,igne\s ,,rocks ,volcanic l&scapes1 :]e activity is v rec5t or /ill 9 progress1 pres5t a numb] ( *>act]i/ic surface-=ms4 ,! cones t h accumulat$ r\nd ! v5ts surpass all o!r hills 9 regul>ity ( outl9e1 & ! crat] 9 ! summit is (t5 relatively l>ge4 ,lava-cones may be /eep-sid$ bosses :5 =m$ ( protrusions ( viscid rocks ri* 9 silica1 l ! rem>kable domes 9 ! nor? ( ,bohemia1 or !y may pres5t v g5tle slopes :]e fluid basic lavas h be5 extrud$4 ,tuff-cones are liable to be brea*$ on "o side1 ow+ to ! outfl[ ( lava :i* ! crat]-wall c\ld n su/a91 & !y !n assume ! =m ( a m\nta9 9 :i* glacial influ5ces h holl[$ out a cirque4 ,ra9 wa%es d[n ! loose mat]ials f great volcanic cones1 & emphasises ! concave curve ( ! m\nta9 sides1 ! =m t is s beautiful 9 ,fuji-yama 9 ,japan1 & :i* ,hokusai1 ) p>donable & affectionate exagg]ation1 reproduc$ 9 a hundr$ illu/rations4 ,ultimately1 h[ev]1 grooves appe> on ! flanks ( ! cone1 9 :i* p]man5t /reams ga!r1 & ! slopes are dissect$ & worn away4 ,dur+ ?is process1 ! tuffs yield /eep & fanta/ic =ms1 & wall-l dykes wea!r out among !m4 ,! dykes are usually ! la/ features to decay4 ,:]e ! v5t has be5 plugg$ ) lava at ! close ( its activity1 ! neck ( rock (t5 rema9s /&+ above ! surr\nd+ c\ntry4 ,! site ( cone aft] cone c be pick$ out 9 ?is way 9 ! ,ca9ozoic volcanic areas ( c5tral ,g]many4 ,! jutt+ crag ( tra*yte or ( basalt has (t5 be5 seiz$ on z ! site ( a feudal ca/le1 "u :i* ! dep5d5t agriculturi/s /ill ga!r at nightfall 9 _! r$-ro($ t[n4 ,! gr\p ( %e]-sid$ necks 9 ! ,hegau 9 s\!rn ,wrttemb]g1 ! ,hoh5twiel1 ,hoh5krh51 & ! re/1 =m a v /rik+ l&scape amid undulat+ ,ca9ozoic l&s4 ,! lava-b$s t cov] wide areas are naturally ( basic composition4 ,basalts ?us =m enorm\s pla9s ) rugg$ surfaces1 on :i* at la/ a r$-br[n soil collects4 ,:5 expos$ to d5udation f ! edge ( ! region inw>ds1 !y develop a m>k$ t]race-/ructure1 ?r\gh :i* ! riv]s cut /eep & grim rav9es4 ,grass may gr[ on ! l$ges & ! tables2 b ! sc>ps1 controll$ by ! well-m>k$ v]tical jo9t+ ( ! lavas1 rema9 %>p & prom95t1 & ! rock falls away f ^! walls 9 :ole columns at a "t4 ,?is /ructure is *>act]i/ically se5 9 nor!rn ,mull & ! adjac5t small] isles1 & is /ill m impressive f ! c5tre to ! nor? ( ,skye1 :]e ! ra9 swept t]races cov]$ by grass & bog & scanty oatfields1 & ! black /eps ( rock betwe5 !m1 pres5t a sc5e ( /range monotony & desolation4 ,9 regions less expos$ to /ormy wea!r1 ! lava-plateaus may provide good soils4 ,= in/ance1 aft] ! great seaw>d sc>p ( ! basalts has be5 cross$ 9 ! c\nties ( ,antrim & ( ,londond]ry1 ! lava-fields1 dropp$ by faults t[>ds ,l\gh ,neagh1 are se5 to be occupi$ by prosp]\s f>ms4 ,9 arid c\ntries1 h[ev]1 ! savage surface ( ! fl[s m]ely becomes modifi$ by r$ du/ & scoriace\s gravel1 worn by w9d & *anges ( temp]ature f ! up/&+ portions ( ! l&4 ,:]e a /ratifi$ c\ntry has be5 freely invad$ by %eets ( lava along its planes ( b$d+1 ! /ratification is emphasis$ 9 any "p expos$ to wea!r+4 ,! resi/+ igne\s rock /&s out 9 sc>ps along ! hills1 & m>ks out any folds t h be5 =m$ s9ce ! epo* ( its intrusion4 ,:5 ! b$s rema9 fairly level1 & are also uplift$1 flat-topp$ hills are =m$ by ! intrusive %eets1 l ^? t may be c>v$ out ( a c\ntry flood$ ov] by lava-/reams4 ,! cry/all9e rock1 v probably a dol]ite1 protects :at lies bel[ x4 ,! kopjes nor? ( ! ,great ,k>roo 9 ! c5tre ( ! ,cape ( ,good ,hope are ?us level on ! cre/ & b\nd$ by a /eep wall or krans ( rock4 ,! edges ( simil> sills ( igne\s rock h controll$ mu* ( ! sc5]y betwe5 ! ,highl& bord] ( ,scotl& & ! ,tyne4 ,a f9e example is ! ind5t$ sc>p ( ! ,great ,:9 ,sill1 a %eet ( dol]ite intrud$ among ! ,c>bonif]\s /rata ( ,nor?umb]l&4 ,?is mass =ms a plat=m = ,bamburgh ,ca/le aga9/ ! wild ,nor? ,sea1 & is traceable s\?-we/w>d across ! c\ntry t[>ds ,c>lisle4 ,nor? ( ,hexham1 its esc>pm5t is occupi$ by ,hadrian's wall1 & ! t[n ( ,borcovicus 0 plant$ on ! edge1 ov]look+ all ,nor?umbria4 ,! f>m]s ( ,nor? ,brita9 & ,irel& h long kn[n up/&+ igne\s dykes z unpr(itable :9/ones4 ,! regul>ity ( direction among dykes ov] v wide areas po9ts to _! intrusion along cracks produc$ by /ret*+ ( ! cru/4 ,radial gr\p+ ( dykes1 su* z "o f9ds ne> volcanic necks1 or1 on a gigantic scale1 r\nd ,ty*o on ! moon1 may be due to explosive action2 b ! majority ( dykes seem to h foll[$ ^u e>?-movem5t4 ,9 ! nor? ( ,irel&1 f ! coa/ ( ,d[n to t ( ,donegal1 a s]ies ( compact rocks ( ,devonian age occurs 9 dykes ly+ almo/ inv>iably nor? & s\?4 ,! po/-,cretace\s dykes ( ! same region h a /ill m uni=m tr5d1 f nor?-we/ to s\?-ea/4 ,su* s]ies ( dykes modify ! sc5]y ( coa/s by =m+ promontories & s]viceable pi]s = boats4 ,! (f%oots ne> ! surface ( a great intrusive mass are f> less regul>4 ,we are "h close to ! zone ( attack1 ! %att]-zone1 & ! /ructures or regul> fracture-planes ( ! ov]ly+ rock only p>tially control ! position tak5 up by ! intrusive magma4 ,irregul> knots & bosses appe> 9 place ( f>-spread+ %eets1 & a network ( cross+ ve9s occurs1 in/ead ( a sy/em ( coord9at$ dykes4 ,! result+ c\ntry is hummocky & brok51 &1 :]e ! cauldron itself has become expos$1 /rik+ contra/s ( surface are se5 z we pass f ! igne\s core to ! old] & frequ5tly /ratifi$ rocks ^u its flanks4 ,"s l>ge bodies ( intrusive rock h1 h[ev]1 be5 =m$ %eet by %eet1 & a b$d$ sill-l /ructure is !n reveal$ 9 !m on wea!r+4 ,sir ,a4 ,geikie#hi calls att5tion to ?is 9 8 description ( ! he>t ( ! black gabbro mass 9 ,skye4 ,b1 z a rule1 ! cont9uity ( /ructure 9 ba?olites1 & _! *>act]i/ic jo9t-planes set at angles to "o ano!r1 cause !m to appe> z massive blocks 9 ! l&scape1 untrav]s$ by any regul> l9es4 ,granite1 ) its broad tabul> jo9t+1 :i* is (t5 develop$ p>allel to a surface ( cool+1 =ms r\nd$ slopes & domes aft] long-cont9u$ wea!r+4 ,:5 re>$ high into ! zone ( fro/-action1 x develops spires & p9nacles1 z 9 ! huge aiguilles ( ,mont ,blanc4 ,b1 z decay goes on1 ! uni=m desc5t ( b\ld]s & s& =ms spread+ taluses1 bank$ aga9/ ! l[] slopes1 :ile ! curv+ jo9ts1 n too closely set1 promote a smoo?ness on ! high] l&s4 ,^! jo9ts1 moreov]1 divide ! rock into b\ld]s almo/ ready-made4 ,tabul> /ructure sometimes pr$om9ates2 b ev5 9 ?is case ! expos$ ends ( ! lay]s soon become r\nd$1 z ! felsp> cry/als pass into a p[d]y /ate4 ,commonly1 a r\gh sph]oidal /ructure prevails1 z may be trac$ 9 _m ( ! ,d>tmoor tors1 & ! blocks t slip away ?r\gh wid5+ ( ! jo9ts become m & m r\nd$ z _! surfaces crumble on ! talus 7,fig4 #ag74 ,illu/ration3 ,fig4 #ag4 ,wea!r+ ,granite4 ,lundy ,isl&4 ,9 tropical l&s1 granite exfoliates "u ! alt]nations ( cle> hot days & cle> cold nights1 & ! jo9t-/ructure all[s ( ! =mation ( great r\nd-back$ surfaces1 on :i* sph]oidal b\ld]s appe> pois$4 ,^! b\ld]s are ! relics ( an ov]ly+ lay] ( granite1 mo/ ( :i* has slipp$ away to ! hill-foot4 ,_! surfaces crumble1 ow+ to ! unequal expansion ( ! con/itu5t m9]als4 ,:5 ! ra9y season sets 91 ! decompos$ cru/ is wa%$ away2 dur+ ! dry season x falls (f 9 flakes & p[d]4 ,9 ?is way ! magnific5t s]ies ( monoli?s t surr\nd ! grave ( ,cecil ,rhodes 9 ! ,matopo ,hills h become sep>at$ out f a cont9u\s %eet ( granite4 ,!y /& n[ l glacial b\ld]s on a surface almo/ z smoo? z t ( a ro*e m\tonne 7,fig4 #ah74 ,! l&scape = miles ar\nd is fanta/ic ) huge fall5 masses1 & ) high-p]*$ blocks t seem ab\t to fall4 ,simil> sc5]y is well kn[n 9 c5tral ,india1 & exfoliation controls ! =m ( m\nta9-domes 9 ,cali=nia & ,brazil4 ,j4 ,c4 ,brann]#ij lays mo/ /ress on temp]ature-*anges 9 ! surface-zone1 & little on orig9al sph]oidal jo9t+1 9 promot+ ! exfoliation ( ! r\nd$ b\ld]s4 ,illu/ration3 ,fig4 #ah4 ,granite wea!r+ "u tropical conditions4 ,rhodes's ,grave1 ,matopo ,hills1 ,s4 ,rhodesia4 ,! blocks l b\ld]s are residues ( a %eet ( granite t once ov]lay ! hill4 ,! basic rocks pres5t f> m rugg$ outl9es4 ,:5 a cauldron occupi$ by basic diorite or by gabbro comes "u d5ud+ action1 ! num]\s cross+ jo9ts oppose ! =mation ( domes or tables4 ,! wea!r wid5s "o groove "h1 ano!r !re2 ! rock breaks away 9 angul> fragm5ts r ?an z a p[d] ov] a broad surface1 & s]rat$ edges & jagg$ p9nacles arise along ! cre/s4 ,! diorites among our old metamorphic rocks 9 ,scotl& or 9 ,irel& c be recognis$ on ! sky-l9e at consid]able di/ances4 ,sir ,a4 ,geikie1 9 8 ,sc5]y ( ,scotl&1 has made ! contra/ betwe5 granite & gabbro 9 ! c5tre ( ! ,isle ( ,skye famili> to all geologi/s4 ,"h ! two types ( rock 7 erupt$ at no long int]val1 & !y h be5 expos$ to d5udation "u ! same conditions4 ,j4 ,maccullo* dwelt 9 #ahaiia on ! relative resi/ance ( ! gabbro & ! rapid dis9tegration ( ! granite hills1 qua9tly rem>k+ ( ! latt] t ! loose /ones1 by _! con/ant desc5t f ! summits1 obscure ! rocky surface1 cov]+ ! sides ) long torr5ts ( r$ rubbi% ev5 m unpleas+ to ! sight ?an _! conoidal =ms4 ,maccullo* not$ t ! loose blocks 9 ! gabbro region lay mu* z !y _h fall51 )\t ! production ( a s&4 ,9 mo/ m\nta9-*a9s produc$ by fold+1 igne\s matt] has be5 =c$ up z an accompanim5t ( ! e>?-movem5ts4 ,! local knots & laccolites1 or ! great cores admitt$ along c]ta9 anticl9es1 /& out on wea!r+ among s*i/ose or /ratifi$ hills4 ,_! surfaces are m>k$ by accid5ts1 & ea* peak z x comes into view (f]s some?+ ( a new surprise4 ,! wall ( ,mont ,blanc f ! angle ne> ,entrves1 & ! huge crag ( ! ,matt]horn above ! valley ( ! ,visp1 h illu/rat$ to e travell] ! dom9ance ( igne\s masses 9 ! l&scape4 ,9 our own isl&s1 ! granites ( ,b5 ,crua*an & ,cairn ,gorm h resi/$ long ages ( d5udation2 an intrusive %eet ( f9] gra9 =ms ! long %e] wall ( ,cad] ,idris2 :ile obsidian lava-fl[s1 n[ grey & dull & cry/all9e1 h furni%$ on ,sn[don ! f9e/ sc5]y ( ,wales4 ,! =tress-t[n ( ,ed9burgh has aris5 on ! relics ( a dead volcano2 & ! high moor ( ,le9/]1 s long ! p]il ( ! ,engli%1 records an igne\s cauldron t has be5 expos$ to d5udation f ! op5+ ( ,devonian times4 ,,*apt] ,,vi ,,metamorphic ,,rocks ,,introduction#ib ,"u ! t]m metamorphism1 consid]$ philologically1 any *ange may be includ$ t is und]gone by rocks aft] _! orig9al deposition4 ,van ,hise1 9 8 monum5tal treatise1 cov]s processes ( cem5tation & alt]ation by p]colat+ wat]s1 z well z ^? l>g] *anges t accompany e>?-movem5t & ! transf]5ce ( rocks into regions ( igne\s activity4 ,x is1 inde$1 impossible to draw any j l9e 9 ?is matt]2 b !re is a g5]al agreem5t t metamorphic rocks are ^? t h be5 alt]$ by heat or pressure or bo?1 ei!r on a local or a regional scale1 ) ! result t new /ructures1 or new m9]als1 or bo?1 h aris5 9 ! mass4 ,! efficacy ( heat alone or ( pressure alone1 ( contact-metamorphism or ( dynamo-metamorphism1 9 produc+ consid]able *anges has be5 mu* debat$4 ,"s ( ! !rmal *anges h be5 already ref]r$ to 9 ! *apt] on igne\s rocks4 ,:ile1 moreov]1 ! new /ructures & ! developm5t ( mica 9 ord9>y slate br+ x into ! metamorphic gr\p1 we h f\nd x conv5i5t to describe ! slates 9 connexion ) common clays4 ,! rocks n[ to be dealt ) give evid5ce ( m extreme *anges1 & ! cry/all9e "* ( _! con/itu5ts is appreciable by ! unaid$ eye4 ,= ! mo/ "p1 !n1 ?is *apt] treats ( gneisses & s*i/s4 ,! wid] use ( ! t]ms s*i/e & s*ief] on ! cont95t ( ,europe makes x necess>y 9 mo/ c\ntries to /yle ! metamorphic =ms cry/all9e s*i/s4 ,ov] wide areas ( c]ta9 c\ntries1 & sometimes :5 we approa* ! localis$ cores ( m\nta9-*a9s1 ! rocks %[ a p>allel arrangem5t ( _! con/itu5ts1 rem9d+ u ( s$im5ts2 b _! con/itu5ts are all cry/all9e1 & !y are m int]lock$ ) "o ano!r ?an is ! case 9 ord9>y /rata4 ,su* rocks h long be5 said to be foliat$4 ,! t]m 0 us$ by ,g4 ,p4 ,scrope z f> back z #ahbe2 b ?is au?or1 9 common ) mo/ geologi/s ( 8 day1 reg>d$ ! m9]al folia z result+ f s$im5tation4 ,d',aubuisson de ,vois9s#ic _h already ref]r$ ! p>allelism ( ! feuillets ( mica 9 s*i/s to "s cause act+ on !m dur+ ! consolidation ( ! rock f a pla/ic /ate2 b x 0 left = ,*>les ,d>w9#id1 9 8 rem>kable obs]vations on metamorphic rocks 9 #ahdf1 to sep>ate cle>ly foliation f /ratification4 ,9 all cases ( metamorphism1 we h to be> 9 m9d t ! alt]ation may be bo? *emical & physical4 ,sub/ances may h be5 remov$ f ! rock1 o!rs may h be5 import$4 ,! cry/all9e con/itu5ts t are n[ pres5t d n necess>ily result f ! cry/allisation ( ! orig9al mat]ials ( ! rock4 ,,mica ,,& ,,hornbl5de ,,s*i/s ,s*i/s are ! ord9>y foliat$ rocks ( f9e or m$ium gra94 ,! folia are really flatt5$ l5ticul> m9]al aggregates1 (t5 b5t & wav$1 ly+ on & aga9/ "o ano!r1 ) _! platy surfaces 9 p>allel planes4 ,!y result 7i7 f ! de=mation "u pressure ( objects already pres5t 9 ! rock1 su* z pebbles or cry/als2 or 7ii7 f ! developm5t ( m9]als "u pressure dur+ ! process ( metamorphism1 su* m9]als be+ all[$ great] facilities = gr[? 9 directions p]p5dicul> to t f :i* ! pressure is ex]t$2 or 7iii7 f ! developm5t ( m9]als1 notably mica1 along ! planes ( weakness provid$ by /ratification or by cleavage4 ,! tr5d ( foliation-planes across a c\ntry is (t51 z ,d>w9 po9t$ out1 rem>kably regul>2 9 "s cases1 x foll[s t ( ! /ratification1 9 o!rs t ( cleavage4 ,! wr9kl+ ( ! foliation mu/ be ascrib$ to subsequ5t compression1 & all ! features se5 9 ! /ra9-slip /ructure ( slate 7p4 #ib7 are repeat$ on a some:at co>s] scale 9 s*i/s4 ,"s s*i/s are und\bt$ly produc$ by ! contact-metamorphism ( %ales4 ,on ! flanks ( m\nta9-*a9s1 :]e argillace\s rocks h be5 ar*$ into domes1 & :]e granite has intrud$ z a core1 ! complete passage c be trac$ f s$im5t to s*i/4 ,! clay-rocks l5d !mselves readily to ! production ( mica1 usually ( ! pale type4 ,&alusite1 & occasionally sillimanite & kyanite1 arise4 ,&alusite (t5 =ms grey prisms ( irregul> outl9e1 resembl+ slate-p5cils1 & /&+ out above ! mica on any wea!r$ surface4 ,alm&9e g>net is almo/ always pres5t4 ,qu>tz occurs 9 /reaks & pat*es1 :i* resolve !mselves into granul> aggregates on microscopic exam9ation4 ,! mica imp>ts a di/9ct foliation to ! mass2 b ! orig9al /ratification is v (t5 pres]v$1 & ! m9]als h develop$ along its planes4 ,small diff]5ces 9 ! con/itution ( ! orig9al /rata give rise to diff]5t types ( s*i/1 int]b$d$ ) "o ano!r4 ,&alusite1 = in/ance1 may occur only 9 c]ta9 argillace\s lay]s1 :ile o!r lay]s are qu>tzose1 ?r\gh ! pres5ce ( orig9al s&4 ,mica-s*i/ is ! commone/ type ( metamorphic rock4 ,:]e m9]alisation has tak5 place ov] a wide area1 x may be difficult to say if ! foliation-planes 9 a s*i/ are ^? ( b$d+1 or ( sup]9duc$ cleavage1 or :e!r !y indicate a slid+ movem5t 9 ! mass "u pressure1 :]eby all prec$+ /ructures h become oblit]at$4 ,amphibole-s*i/1 (t5 /yl$ epidiorite1 consi/s ( foliat$ hornbl5de1 or its gre5] ally act9olite1 associat$ ) granul> felsp> & sometimes ) equally granul> qu>tz4 ,! amphibole be+ usually prismatic1 ! cry/als are f\nd ) _! long] axes arrang$ 9 p>allel planes1 & (t5 /reak$ out p>allel to "o ano!r4 ,m9ute wr9kl+s1 due to subsequ5t yield+1 are n s frequ5t z 9 mica-s*i/s4 ,amphibole-s*i/s occur commonly z knots & some:at irregul> masses among mica-s*i/s1 & repres5t basic igne\s rocks t 7 int]b$d$ or intrusive 9 ! s$im5t>y s]ies4 ,! pyrox5e ( ! orig9al rock has become recry/allis$ z hornbl5de1 & ! felspa?ic con/itu5t has re>rang$ itself 9 granul> =ms4 ,j4 ,j4 ,h4 ,teall#ie has describ$ 9 int]e/+ detail an example f ! old] rocks ( ,su!rl&1 & 8 pap] conta9s a useful discussion ( problems ( pressure-metamorphism4 ,,amphibolites ,hornbl5de-s*i/s are (t5 se5 to pass into true diorites2 b !y also h relation%ips ) ! m puzzl+ rocks kn[n z amphibolites4 ,^!1 aga91 graduate into pyrox5ites1 or rocks ri* 9 pyrox5e1 ) granul> qu>tz & tricl9ic felsp>1 & into eclogites1 :i* may be def9$ z pyrox5ites ) g>net4 ,pyrox5e-eclogite1 9 ,s\? ,africa1 is associat$ ) diamond#if1 & fragm5ts ( explod$ eclogite ab\nd 9 ! igne\s v5ts f :i* ! diamonds are extract$4 ,:at has be5 call$ pyrox5e-granulite is a d>k granul> eclogite1 includ+ rhombic pyrox5e side by side ) g>net1 & associat$1 9 ,saxony & ,skye1 ) igne\s intrusions4 ,9 bo? localities x has be5 %[n to result f ! inclusion ( basic rocks1 su* z dol]ites & gabbros1 9 a ba? ( "s invad+ magma4 ,! l5s-l =m ( ! ,saxon masses1 & ! occurr5ce also ( %eets ( pyrox5e-granulite int]lam9at$ ) f9e-gra9$ granite1 7 till lately attribut$ to ! roll+-out action ( pressure-metamorphism4 ,by :at ,h4 ,cr$n] calls a complete rev]sal ( op9ion1 due ma9ly to ! op5+ ( new railway-sections1 ! granul> eclogites ( ,saxony are n[ reg>d$ z products ( extreme contact-alt]ation1 comb9$ ) igne\s fl[#ig4 ,a4 ,h>k]#ih simil>ly po9ts out t examples 9 ,skye are d]iv$ f basaltic lavas1 into :i* gabbro has intrud$1 produc+ a complete recon/ruction ( ! rock4 ,:]e a s]ies ( igne\s rocks & s$im5ts1 9 "s cases already alt]$ by pressure1 has be5 attack$ & p>tly melt$ up by granite1 amphibolite-blocks are f\nd z ! common residue 9 ! m+l$ mass4 ,! qu>tzites & mica-s*i/s ( ! mantle t ov]lies ! granite dome may h disappe>$ by /op+ & absorption 7see p4 #abf74 ,rocks ri* 9 amphibole rema91 & !y commonly conta9 pyrox5e z well z hornbl5de4 ,9 "s cases1 z 9 ,skye & ,saxony1 !y may be trac$ to basic igne\s rocks2 b 9 o!rs !y may be ref]r$ ) equal c]ta9ty to lime/one4 ,! int]action ( ! granite magma & ! calc>e\s s$im5t has produc$ a silicate rock completely diff]5t f ei!r4 ,lvy#ii & ,lacroix h %[n h[ ! amphibolites ( ,france may sometimes repres5t dol]ites1 sometimes lime/ones4 ,_! "w has rec5tly receiv$ /rik+ support f ! obs]vations ( ! ,geological ,survey ( ,canada#ajj4 ,/reaky hornbl5de-gneisses ov] wide areas ( ,ont>io are n[ attribut$ to ! p>tial absorption ( ov]ly+ lime/one by :at 0 once reg>d$ z a fundam5tal granite4 ,! amphibolite blocks h become drawn out into b&s t foll[ all ! fl[-/ructure ( ! invad+ igne\s mass4 ,a small area ( ! same k9d 0 /udi$ 9 #aijj 9 nor?-we/ ,irel&#aja1 :]e a rem>kably pure granitoid rock1 consi/+ ( qu>tz & alkali felsp>1 has become enri*$ ) d>k mica at ! exp5se ( blocks ( amphibolite includ$ 9 x4 ,,metamorphic ,,m>bles ,,& ,,qu>tzites ,"s ( ! *anges t conv]t lime/one into cry/all9e m>ble h already be5 ref]r$ to on pp4 #cf & #ed4 ,! pres5ce ( mica 9 lime/ones may all[ ( foliation :5 pressure comes to be appli$ to !m1 & calc-s*i/s result4 ,! mica may be detrital1 or may arise ?r\gh ! metamorphism ( clayey b&s2 b x =ms weak lay]s1 along :i* ! %e>+ movem5ts take place :i* lead to a s*i/ose /ructure 9 ! mass4 ,pure granul> m>ble may also occasionally become conv]t$ into a calc-s*i/1 by de=mation ( its cry/all9e gra9s along glid+ planes )9 ea* cry/al4 ,:5 we consid] qu>tzites1 ! same "q rises z 9 ! case ( cry/all9e lime/ones1 & x is (t5 difficult to /ate t a qu>tzite owes its *>act]s to metamorphism4 ,microscopic exam9ation sometimes reveals ! effects ( e>?-pressures 9 ! cru%$ & p[d]$ condition ( ! l>g] gra9s2 & no rocks exhibit ! p[] ( su* pressures 9 produc+ /ructural modifications m /rik+ly ?an ! co>se qu>tz-grits t are sometimes involv$ 9 regions ( dynamic metamorphism4 ,pebbles & gra9s are alike de=m$1 press$ out along planes ( fracture1 & f9ally r$uc$ to b&s ( p[d]$ qu>tz4 ,:5 felspa?ic pebbles occur 9 ^! grits1 ! result+ s*i/ose mass has almo/ ! appe>ance ( a b&$ igne\s rock1 & /reaky :ite mica may arise f ! alt]ation ( potassium felsp>4 ,"s s&/ones conta9 suffici5t felsp> or calcium c>bonate to =m a flux :5 !y are subject$ to !rmal metamorphism4 ,at times a glass ?us arises betwe5 ! gra9s1 & reacts ^u ! orig9al qu>tz4 ,:5 ! igne\s magma has melt$ up a s&/one or a qu>tzite1 blocks ( ! s$im5t may rema9 surr\nd$ by a mix$ & recry/allis$ product f bo? rocks4 ,wright & ,bailey#ajb h /udi$ an example 9 ,colonsay1 :]e a hornbl5de rock has p>tly dissolv$ a qu>tzite1 ! residual blocks be+ surr\nd$ by halos ( int]action1 compos$ ( qu>tz & alkali felsp>4 ,,gneisses ,gneisses may be broadly def9$ z b&$ cry/all9e rocks 9 :i* felsp> is visible to ! unaid$ eye4 ,?\gh ?is w include _m igne\s masses1 x is d\btful if a m rigid description c be giv54 ,num]\s gneisses1 9 fact1 owe _! p>allel /ructures to fl[ :ile 9 a molt5 /ate4 ,o!rs are rocks t h be5 de=m$ by pressure1 & _! con/itu5ts h become drawn out along planes ( solid fl[4 ,:]e actual %e>+ has tak5 place1 ! m9]als 9 ! close neighb\rhood ( ! planes ( movem5t may become especially modifi$1 gr\nd d[n1 & de=m$4 ,! foliat$ /ructure may !n be m>k$ by ! appe>ance ( diff]5tiat$ b&s4 ,su* b&s may also arise f ! spread+ out "u pressure ( c]ta9 l>ge con/itu5ts1 su* z porphyritic cry/als ( felsp>1 :i* produce :ite b&s1 or ( pyrox5e1 :i* w become modifi$ into granul> amphibole & w produce d>k /reaks ?r\gh ! rock4 ,illu/ration3 ,fig4 #ai4 ,composite ,gneiss4 ,g>tan ,l\gh1 ,co4 ,donegal4 ,fragm5ts ( mica-s*i/ project f a gneiss1 ! b&+ ( :i* foll[s ! foliation planes ( ! s*i/4 ,on ! "r ! mass reta9s less s*i/ & is m granitic4 ,gneisses may also result f ! intrusion ( felspa?ic igne\s rocks1 9 %eets ( v>y+ ?ickness1 betwe5 ! lay]s ( a s$im5t or a s*i/ 7,fig4 #ai72 or f ! intrusion ( "o igne\s rock into ano!r1 ) v>y+ degrees ( int]action & absorption4 ,x has (t5 be5 presum$ t ! invad$ igne\s rock mu/ h be5 9 su* cases 9 a pla/ic /ate4 ,! supply ( heat )9 ! e>? dur+ su* processes1 & ! action ( ! gases1 corrod+1 z ,doelt] says1 l a bl[pipe-flame1 are1 h[ev]1 cle>ly suffici5t to melt d[n l>ge blocks1 ! residue be+ !n c>ri$ =w>d z wisps or b&s 9 ! invad]4 ,_m /rik+ly b&$ gneisses are ?us ( composite orig94 ,_! felspa?ic granitoid b&s c be trac$ 9 ! field to an igne\s s\rce1 :ile _! d>k] & usually micace\s lay]s c z surely be attribut$ to ! invasion & incorporation ( adjac5t s*i/s 7,fig4 #bj74 ,b x is q possible t 9 o!r cases ! b&$ gneiss is a s$im5t>y rock :i* has und]gone :at ,judd#ajc has /yl$ /atical metamorphism4 ,! diff]5ces 9 successive b&s are !n due to orig9al diff]5ces 9 successive /rata2 "o has yield$ a granitic lay]1 "o a lay] ( qu>tzite1 "o1 :i* 0 m argillace\s1 a lay] ( mica-s*i/4 ,! b&s 9 su* a gneiss record ! /ratification4 ,illu/ration3 ,fig4 #bj4 ,composite ,gneiss =m$ by intrusion ( granite into hornbl5de-s*i/4 ngn1 ne> ,saltsjbad51 ,sw$54 ,gneisses are (t5 describ$ z if !y consi/$ ( lay]s ( v>i\s m9]als1 qu>tz1 felsp>1 & mica1 alt]nat+ "o ) ano!r4 ,z a matt] ( fact1 a gneiss may exi/ 9 :i* !re is no diff]5tiation into lay]s2 ! :ole ( ! con/itu5ts h be5 drawn out & elongat$1 any mica pres5t becom+ naturally conspicu\s by its flatt5$ wisp-l =ms4 ,! b&$ gneisses1 on ! o!r h&1 :]e lay]-/ructure is obvi\s1 consi/ 9 reality ( b&s ( diff]5t rock-types4 ,sometimes all ! lay]s are granitoid1 b "o b& w conta9 only qu>tz & felsp>1 :ile ano!r w conta9 ! same m9]als ) an admixture1 & p]haps a great pr$om9ance1 ( mica4 ,g4 ,p4 ,scrope#ajd made an imm5se /ep =w>d :5 he realis$ 9 #ahbe t su* b&$ rocks1 ! inf]ior cry/all9e zones1 might be pu%$ out ( position & protrud$ among o!rs 9 a solid or ne>ly solid /ate4 ,he goes on1 ,! protrusion ( ! foliat$ rocks1 gneiss1 mica-s*i/1 clay-slate1 etc4 0 *iefly occasion$ by _! peculi> /ructure2 ! p>allel plane surfaces ( _! compon5t cry/als1 p>ticul>ly ! plates ( mica1 slid+ ) facility ov] "o ano!r2 :ile ! lam9> /ructure ( ^! rocks 0 9 turn increas$ dur+ ?is process1 ! cry/als be+ elongat$ 9 ! direction ( _! motion1 z 9 ! case ( ! cl9k/ones & pe>l-/ones ( ! tra*ytic =mation4 ,aft] ?is1 !re 0 little left = ! lat] advocates ( dynamo metamorphism to put =w>d4 ,:ile ,d>w9#aje recognis$ h[ ! granite at ,cape ,t[n _h work$ its way insidi\sly betwe5 ! lay]s ( a s*i/1 x 0 left = ,mi*el ,lvy to emphasise ! "p play$ by :at is call$ lit-p>-lit injection 9 ! mak+ ( b&$ gneiss 7see p4 #abj74 ,k4 ,a4 ,loss51 ,johann ,lehmann1 & o!r di/+ui%$ work]s 9 ,g]many made cle>1 on ! o!r h&1 ! effects ( pressure 9 m\ld+ & re=m+ cry/all9e rocks1 & ev5 9 br++ ab\t ! cry/allisation ( c]ta9 m9]als 9 a previ\sly s$im5t>y mass4 ,! dynamo-metamorphic s*ool assum$ imm5se importance f #ahhd onw>ds1 ! date ( ! publication ( ,lehmann's "w on ,die ,ent/ehung d] altkry/all9is*5 ,s*ief]ge/e9e1 & = a "t ! intrusion ( igne\s masses 0 held1 bo? 9 ,g]many & ! ,briti% ,isles1 to h _h a m]ely local significance z a metamorphic ag5t4 ,:]ev] regional metamorphism 0 spok5 (1 pressure-effects 7 held to be pr$om9ant4 ,inde$1 ! pr(\nd modifications t may occur 9 rocks :5 l[]$ into subt]ranean cauldrons is only n[ becom+ g5]ally realis$4 ,! t5d5cy to reg>d ! /ructures ( l>ge masses ( gneiss z ( necessity due to de=mation & %e>+ 9 a solid /ate has1 h[ev]1 pass$ away#ajf4 ,pressure-effects are ( c\rse cle>ly traceable 9 mo/ gneisses1 & are ( imm5se importance 9 _m metamorphic areas2 b we f9d aga9 & aga9 t gneissic /ructure has be5 injur$ r ?an develop$ by cru%+ subsequ5t to ! consolidation ( ! rock4 ,9 "s cases1 :]e ?is /ructure is due to igne\s fl[1 :i* ( c\rse (t5 took place "u consid]able pressure1 ev5 ! puck]+s ( ! /ratifi$ or foliat$ rock :i* 0 invad$ by ! igne\s magma h be5 foll[$ by ! invad+ %eets4 ,9 o!r cases1 z 9 ! composite amphibolite gneiss ( ,canada1 or ! simil> rocks ( ! ,ox ,m\nta9s 9 ,irel&1 ! contortions 9 ! m+l$ mass are cle>ly due to ! viscid fl[ ( ! consolidat+ invad]4 ,! gr[+ appreciation ( ! views on recurr5t !rmal metamorphism t 7 orig9ally prop\nd$ by ,james ,hutton 9 #aghe has l$ to ! assignm5t ( f> y\ng] ages to _m masses previ\sly reg>d$ z fundam5tal & ,ar*an4 ,"s ( ^! rocks are und\bt$ly ( high antiquity1 b are f\nd to be intrusive 9 /rata ( a late pre-,cambrian s]ies4 ,o!rs1 su* z ! mat]ial ( ! ,saxon laccolite1 & ! gneisses on ! nor?-ea/ ,bohemian bord]1 are n[ kn[n to be ( ,upp] ,palozoic age4 ,,! ,,"q ,,( ,a ,,fundam5tal ,,gneiss ,ev] s9ce ,a4 ,c4 ,lawson#ajg %[$ 9 ,canada h[ ! ,laur5tian gneiss _h invad$ & swall[$ up ! ov]ly+ ,huronian rocks1 suspicion began to fall on ! doctr9e ( a fundam5tal gneiss4 ,we may n[ well ask ourselves ! foll[+ que/ions3-- 7i7 ,0 !re a "t 9 ! e>ly hi/ory ( our globe :5 s*i/s & gneisses 7 deposit$ z a preval5t type ( s$im5t1 "u conditions :i* h n s9ce recurr$8 7ii7 ,if s1 :i* ( ! *>act]s ( ^! pre-,cambrian rocks are orig9al1 & :i* h be5 acquir$ ?r\gh subsequ5t metamorphism8 7iii7 ,on ! o!r h&1 is ! preval5ce ( gneiss & s*i/ 9 e>ly pre-,cambrian gr\ps ( rock due to ! fact t1 ! old] ! rock1 ! m metamorphism1 by recurr5t heat & pressure1 x is likely to h und]gone8 7iv7 ,we may pref] ! !ory ( ,laplace1 t ! e>? is cool+ f a molt5 /ate2 or ! planetesimal !ory1 accord+ to :i* heat has be5 develop$ dur+ ! consolidation & contraction ( an agglom]ate ( solid p>ticles2 yet 9 ei!r case we mu/ admit t ! e>?'s out] lay]s 7 once ne>] to ! heat$ p>ts ( ! e>? ?an !y are n[4 ,is x n likely1 !n1 t e>ly s$im5ts became frequ5tly imm]s$ 9 ba?s ( molt5 matt]1 & t contact-metamorphism & admixture on a regional scale h produc$ 9 !m ! *>act]s t h be5 attribut$ to a fundam5tal gneiss#ajh8 ,j4 ,j4 ,s$]holm#aji has trac$ 9 ,f9l& f\r gr\ps ( ,ar*an s$im5t>y mat]ial1 :i* h be5 successively invad$ by granite f ! dep?s4 ,! b>e wave-swept isles ( ,spik>na1 ea/ ( ,hang1 s]ve z models ( /ructures t are traceable ?r\gh\t ! ,baltic l&s4 ,! m we reg>d ! olde/ gneisses ( "o region aft] ano!r1 ! m we see 9 !m igne\s matt] t has attempt$ to assimilate s$im5ts ( /ill old] date4 ,! b&$ /ructures t h be5 appeal$ to z indicat+ ! p[] ( e>?-movem5ts to de=m ! solid cry/all9e cru/ prove1 9 v _m cases1 to record ! foliation ( rocks t 7 already metamorphos$ be=e ! igne\s matt] spread among !m4 ,9 "s ( ^! cases1 ?is foliation foll[$ planes ( orig9al /ratification1 & we are =c$ to conclude t true s$im5t>y /ructure may aft] all control ! features ( a gn>l$ & contort$ fundam5tal gneiss4 ,we are /ill f> f discov]+ ! primitive cru/ =m$ ab\t a molt5 globe1 & ! brilliant pro(s ( evolution 9 ! organic _w are unmat*$ by any evid5ce ( ! evolution ( rock-types dur+ geological "t4 ,,metamorphic ,,rocks ,,& ,,sc5]y ,metamorphic rocks are usually associat$ ) ! sc5]y ( m\nta91 moor1 & =e/4 ,! highly alt]$ silice\s masses furni% b indiff]5t soils4 ,! connexion betwe5 metamorphic rocks & e>?-crumpl+1 & _! frequ5t p5etration by granite1 lead to ! production ( rugg$ ridges & high moorl&s1 among :i* d5udation has cut romantic gl5s4 ,! s*i/s wea!r out on ! valley-walls along _! foliation-surfaces1 & sc>ps arise l ^? ( /ratifi$ rocks4 ,! face ( su* a sc>p is brok5 away 9 a zigzag & spl9t]y fa%ion1 & ! %>p edges ( ! foliat$ mass /& out l tee? ^u ! sky-l9e4 ,gneisses associat$ ) ! s*i/s pres5t a contra/ ( smoo!r surfaces1 :]ev] d5udation has be5 long cont9u$4 ,foliat$ diorites & amphibolites1 h[ev]1 may produce wild crags t ev5 ov]hang2 :ile rec5tly expos$ gneiss1 at high altitudes1 may give rise to p9nacles & s]rat$ =ms4 ,:]e alt]nations ( qu>tzite & mica-s*i/ occur1 irregul>ities ( ! surface are readily ma9ta9$4 ,hea!r climbs ^u ! yell[ soils furni%$ by ! s*i/1 & trees may ga!r 9 its holl[s2 b ! qu>tzite /&s out b>e & dom9ant4 ,9 "s cases ! upturn$ b$s ( ! latt] wea!r out l dykes across ! c\ntry4 ,worn-d[n plateaus ( anci5t gneiss1 ! m]e residues ( m\nta9-l&1 may be se5 9 ! /orm-swept levels ( ! ,out] ,hebrides1 & 9 ! hummocky c\ntry1 a swell+ sea ( b>e grey rock & peat-fill$ holl[s1 t bord]s all ! we/ ( ,su!rl&4 ,! irregul> wea!r+ ( mica-s*i/1 & ! read9ess ) :i* x c be c>v$ by /reams1 control ! bold l&scapes ( ! highl&s f ! ,trossa*s to ,l\gh ,ness1 & !nce away aga9 to ! nor!rn sea4 ,"h & !re1 great domes ( intrusive granite rise amid ! brok5 moorl&s2 at times1 a :ite cone ( qu>tzite cat*es ! eye ) a gleam l t ( sn[4 ,we may trav]se ?is c\ntry z an introduction to ! high glacial plateaus & deeply not*$ seaw>d slopes ( ! metamorphic l&s ( ,norway2 or to ! contra/s ( jagg$ s*i/s & resi/+ gneisses t meets u z we ne> ! ,alp9e core4 ,,ref]5ces 7,! numb]s ( volumes are giv5 ?r\gh\t 9 ?ick type2 ! dates are betwe5 brackets1 & ! page-ref]5ces foll[ 9 ord9>y figures47 ,footnote #a3 ,cordi]1 ,mmoire sur les sub/ances dites en masse1 qui entr5t dans la composition des ,ro*es ,volcaniques1 ,j\rn4 de ,physique1 #hc 7#ahaf71 #ace1 #bhe1 & #ceb4 ,footnote #b3 ,on specific gravity ( m9]al gra9s see especially ,w4 ,j4 ,sollas1 ,nature1 #dc 7#ahia71 #djd4 ,footnote #c3 ,sorby1 ,q4 ,j\rn4 ,geol4 ,soc4 ,london1 #ad 7#aheh71 #dec4 ,footnote #d3 ,katz]1 ,geologis*] ,fhr] dur* ,bosni51 ,,ix int]nat4 ,geolog5congress 7#aijc71 #aij4 ,footnote #e3 ,a4 ,w4 ,rog]s1 ,geology ( ,cape ,colony1 ed4 #b 7#aiji71 #dja4 ,footnote #f3 ,l9ck1 ,die ,bildung d] ,ooli! u4 ,rog5/e9e1 ,neues ,jahrb4 fr ,m941 #af 7#aijc71 #die4 ,footnote #g3 ,daly1 ,! ,limeless ,ocean1 ,am]4 ,j\rn4 ,sci41 ,s]4 #d1 #bc 7#aijg71 #ajd1 & ,evolution ( ! ,lime/ones1 ,bull4 ,geol4 ,soc4 ,am]4 #bj 7#aiji71 #aec4 ,footnote #h3 ,a4 ,r4 ,horwood1 ,geol4 ,mag4 7#aiaj71 #agc2 & ,cole & ,little1 ibid4 7#aiaa71 #di1 ) ref]5ces to lit]ature4 ,footnote #i3 ,! ,atoll ( ,funafuti1 ,roy4 ,soc4 ,london 7#aijd74 ,footnote #aj3 ,m4 ,ogilvie 7,gordon71 ,coral 9 ! ,dolomites1 ,geol4 ,mag4 7#ahid71 #a & #di1 & lat] pap]s4 ,footnote #aa3 ,g>d9] & ,reynolds1 ,! ,portra9e ,inli] 7,co4 ,dubl971 ,q4 ,j\rn4 ,geol4 ,soc41 #ec 7#ahig71 #ecb4 ,footnote #iaa3 ,wal!r1 ,e9leitung 9 die ,geologie als hi/oris*e ,wiss5s*aft2 #ct]4 ,!il1 ,li?og5esis d] ,geg5w>t 7#ahid71 #gjg4 ,footnote #ab3 ,see ,ni*ols1 ,field ,columbian ,museum1 ,geology1 #c 7#aijf74 ,footnote #ac3 ,skeats1 ,lime/ones f uprais$ coral isl&s1 ,bull4 ,mus4 ,comp4 ,zool4 ,h>v>d1 #db 7#aijc71 ,no4 #b4 ,footnote #ad3 ,see g5]ally ,w4 ,meig51 ,neu]e ,arbeit5 b] die ,ent/ehung des ,dolomits1 ,geol4 ,runds*au1 #a 7#aiaj71 #di4 ,footnote #ae3 ,skeats1 ,orig9 ( ! ,dolomites ( s\!rn ,tyrol1 ,q4 ,j\rn4 ,geol4 ,soc41 #fa 7#aije71 #ig4 ,footnote #af3 ,pfaff1 ,beitrge b] die ,ent/ehung des ,magnesits u4 ,dolomits1 ,neues ,jahrb4 fr ,m941 ,beilage ,bd4 #i 7#ahid71 #dhe4 ,footnote #ag3 ,g>wood1 ,on ! orig9 ( ! concretions 9 ! ,magnesian ,lime/one ( ,durham1 ,geol4 ,mag4 7#ahia71 #dcc4 ,footnote #ah3 ,skeats1 op4 cit41 ref4 #ae1 p4 #ace4 ,footnote #ai3 ,j4 ,j4 ,h4 ,teall1 ,on d$olomitisation1 ,geol4 ,mag4 7#ahia74 #eac1 & ,rep4 ,brit4 ,assoc4 7#aijc74 ,footnote #bj3 ,j4 ,s4 ,h[e1 ,geology ( ,build+ ,/ones 7#aiaj71 #cec4 ,footnote #ba3 ,h9de1 ,on ,b$s ( ,sponge rema9s 9 ! s\? ( ,engl&1 ,phil4 ,trans4 7#ahhe71 ,pt4 #b1 #dbg4 ,footnote #bb3 ,sollas1 ,on ! /ructure ( ! g5us ,catagma1 ,ann4 & ,mag4 ,nat4 ,hi/41 ,s]4 #e1 #b 7#ahgh71 #cfa4 ,also ibid41 #f 7#ahhj71 #ddg4 ,footnote #bc3 ,cayeux1 tude micrographique des ,t]ra9s sdim5taires1 ,mm4 ,soc4 ,gol4 du ,nord41 #d 7#ahig71 #ddc4 ,footnote #bd3 ,jukes-,br[ne1 ,! am\nt ( dissem9at$ silica 9 ! ,*alk 9 relation to fl9ts1 ,geol4 ,mag4 7#ahic71 #ede4 ,footnote #be3 ,guppy1 ,obs]vations ( a ,naturali/ 9 ! ,pacific3 ,vanua ,levu 7#aijc71 *ap4 xxv4 ,footnote #bf3 ,rog]s1 op4 cit41 ref4 #e1 p4 #djc4 ,footnote #bg3 ,judd1 ,on ! unmak+ ( ,fl9ts1 ,proc4 ,geol4 ,assoc41 #aj 7#ahhg71 #bag4 ,also ,h9tze1 ,h&bu* d] ,m9]alogie1 #a 7#aijf71 #adgc4 ,footnote #bh3 ,grund1 9 ,/ille's ,geologis*e ,*>akt]bild]1 ,heft #c 7#aiaj74 ,footnote #bi3 ,rullmann1 ,h&bu* d] te*nis*5 ,mykologie1 #c 7#aijd-f71 & refs4 9 ,c5tralblatt fr ,bakt]iologie 7#aijd & onw>ds74 ,footnote #cj3 ,h9de1 ,catalogue ( ,fossil ,sponges1 ,brit4 ,mus4 7#ahhc71 #bh4 ,footnote #ca3 ,rog]s1 ,geology ( ,cape ,colony1 ed4 #a 7#aije71 #cgc4 ,footnote #cb3 ,ibid41 #ceg4 ,footnote #cc3 ,lyons1 ,libyan ,des]t1 ,q4 ,j\rn4 ,geol4 ,soc41 #ej 7#ahid71 #ecd & #ede4 ,footnote #cd3 ,victorian ,naturali/1 #bg 7#aiaj71 #ij4 ,footnote #ce3 ,sorby1 ,/ructure & orig9 ( non-calc>e\s /ratifi$ rocks1 ,q4 ,j\rn4 ,geol4 ,soc41 #cf 7#ahhj71 ,proc41 #fc4 ,footnote #cf3 ,phillips1 ,con/itution & hi/ory ( ,grits & ,s&/ones1 ibid41 #cg 7#ahha71 #f4 ,footnote #cg3 ,a4 ,daubre1 ,geologie exprim5tale 7#ahgi71 #bef4 ,footnote #ch3 ,phillips1 op4 cit41 ref4 #cf1 p4 #bf4 ,footnote #ich3 ,j4 ,b>rell %[s h[ w9d-borne s& may =m a cov]+ to ! dry & sun-crack$ surface ( a lake-deposit2 ,relation betwe5 climate & t]re/rial deposits1 ,j\rn4 ,geol41 #af 7#aijh71 #bhj4 ,footnote #ci3 ,lake & ,ra/all1 ,text-book ( ,geology 7#aiaj71 #big4 ,comp>e ,c4 ,lapwor?1 ,int]m$iate ,text-book ( ,geology 7#ahii71 #agf1 & ,geological ,/ructure ( ,n4 ,w4 ,highl&s1 ,geol4 ,surv4 ,scotl& 7#aijg74 ,footnote #ici3 ,see ,a4 ,b4 ,se>le1 ,! ,natural ,hi/ory ( ,clay 7#aiab74 ,footnote #dj3 ,hall1 ,! ,soil1 ed4 #b 7#aijh71 #cd1 & ,e4 ,j4 ,russell1 ,clay1 ,/&>d ,cyclop$ia ( ,mod]n ,agriculture 7#aijh74 ,footnote #da3 ,reade & ,holl&1 ,s&s & ,s$im5ts1 ,proc4 ,liv4 ,geol4 ,soc4 7#aijc-f74 ,footnote #db3 ,&russ[1 ,la ,m] ,noire1 ,guide des ,excursions1 viime ,congrs gol4 int]nat4 7#ahig74 ,footnote #dc3 ,b4 ,smi?1 ,upp] ,keup] ,s&/one1 ,geol4 ,mag4 7#aiaj71 #cjb4 ,comp>e ,f4 ,cresswell1 ,trans4 ,leice/] ,lit4 & ,phil4 ,soc4 7#aiaj74 ,footnote #dd3 ,j4 ,murray & ,a4 ,r5>d1 ,deep ,sea ,deposits1 ,*all5g] ,rep4 7#ahia71 #bca4 ,footnote #de3 ,ibid41 #bcd4 ,footnote #df3 ,ibid41 #bbi4 ,footnote #dg3 ,h>k]1 ,slaty ,cleavage & alli$ rock-/ructures1 ,rep4 ,brit4 ,assoc4 7#ahhe74 ,footnote #dh3 ,lei?1 ,rock ,cleavage1 ,bull4 ,u4 ,s4 ,geol4 ,surv41 ,no4 #bci 7#aije74 ,footnote #di3 ,lamplugh1 ,geology ( ,isle ( ,man1 ,mem4 ,geol4 ,surv4 ,gt4 ,brit4 7#aijc71 #gb-hf4 ,footnote #ej3 ,d>w91 ,geological ,obs]vations on ,s4 ,am]ica 7#ahdf71 *ap4 vi4 ,footnote #ea3 ,reade & ,holl&1 ,gre5 ,slates ( ! ,lake ,di/rict1 ) a ,!ory ( ,slaty ,cleavage1 ,proc4 ,liv4 ,geol4 ,soc4 7#aijj-a71 #abd4 ,footnote #eb3 ,a4 ,h>k]1 ,on 'eyes' ( ,pyrites c41 ,geol4 ,mag4 7#ahhi71 #cif4 ,footnote #ec3 ,t4 ,n4 ,dale illu/rates an extreme case1 ,slate ,deposits ( ,u4,s41 ,bull4 ,u4,s4 ,geol4 ,surv41 ,no4 #bge 7#aijf71 #ca4 ,footnote #ed3 ,h>k]1 op4 cit41 ref4 #dg1 p4 #ai4 ,footnote #ee3 ,lei?1 op4 cit41 ref4 #dh1 p4 #aeb4 ,footnote #ef3 ,i4 ,russell1 ,glaci]s ( ,n4 ,am]ica 7#ahig71 #be4 ,footnote #eg3 ,see1 = in/ance1 ,t4 ,w4 ,edgewor? ,david1 ,evid5ces ( glacial action 9 ,au/ralia1 ,q4 ,j\rn4 ,geol4 ,soc41 #eb 7#ahif71 #bhi4 ,footnote #eh3 ,= g5]al discussions ( ,igne\s ,rocks1 see ,j4 ,j4 ,h4 ,teall1 ,briti% ,petrography 7#ahhh72 ,h4 ,ros5bus*1 ,mikroskopis*e ,physiographie1 ed4 #d 7#aije-g72 ,f4 ,zirkel1 ,lehrbu* d] ,petrographie1 ed4 #b 7#ahid72 ,a4 ,h>k]1 ,natural ,hi/ory ( ,igne\s ,rocks 7#aiji72 ,j4 ,p4 ,idd+s1 ,igne\s ,rocks1 #a 7#aiji74 ,footnote #ei3 ,cross1 ,idd+s1 ,pirsson1 & ,wa%+ton1 ,quantitative ,classification ( ,igne\s ,rocks 7#aijc74 ,footnote #fj3 ,h>k]1 op4 cit41 ref4 #eh1 p4 #ahf4 ,footnote #fa3 ,idd+s1 op4 cit41 ref4 #eh1 p4 #acj c4 ,footnote #fb3 ,ibid41 pp4 #bbh-bda4 ,footnote #fc3 ,scrope1 ,consid]ations on ,volcanos 7#ahbe71 #ada4 ,footnote #fd3 ,g4 ,a4 ,j4 ,cole & ,j4 ,w4 ,gregory1 ,v>iolitic ,rocks ( ,mt ,g5vre1 ,q4 ,j\rn4 ,geol4 ,soc41 #df 7#ahij71 #caa4 ,footnote #fe3 ,a4 ,geikie1 ,anci5t ,volcanoes ( ,gt ,brita91 #a 7#ahig71 #be4 ,also ,c4 ,reid & ,h4 ,dewey1 ,pill[ lava ( ,cornwall1 ,q4 ,j\rn4 ,geol4 ,soc41 #fd 7#aijh71 #bfd4 ,footnote #ff3 ,&]son1 ,volcano ( ,matavanu1 ibid41 #ff 7#aiaj71 #fcb4 ,footnote #fg3 ,dewey & ,flett1 ,briti% ,pill[ lavas1 ,geol4 ,mag4 7#aiaa71 #bjb & #bda4 ,footnote #fh3 ,/e9mann1 ,die ,s*>dts*e ,ueb]faltung/heorie c41 ,b]4 nat4 ,gesell4 ,freiburg i4 ,b41 #af 7#aije71 #dd4 ,footnote #fi3 ,doelt]1 ,petrog5esis 7#aijf71 #cc & #aji-abc4 ,footnote #gj3 ,h>k]1 op4 cit41 ref4 #eh1 p4 #hb4 ,footnote #ga3 ,idd+s1 op4 cit41 ref4 #eh1 p4 #bhj4 ,footnote #gb3 ,brgg]1 ,die ,eruptionsfolge bei ,pr$azzo1 ,vid5sskab4 ,skrift] 7#ahie71 ,no4 #g1 p4 #aeb4 ,footnote #gc3 ,daly1 ,second>y orig9 ( c]ta9 ,granites1 ,am4 ,j\rn4 ,sci41 ,s]4 #d1 #bj 7#aije71 #ahe1 ) useful ref]5ces to ,bayley & o!rs4 ,footnote #gd3 ,hawes1 ,! ,albany granite & its contact ph5om5a1 ibid41 ,s]4 #c1 #ba 7#ahha71 #ca4 ,footnote #ge3 ,g4 ,a4 ,j4 ,cole1 ,geology ( ,slieve ,gallion1 ,sci4 ,trans4 ,r4 ,dubl9 ,soc41 #f 7#ahig71 #bdb4 ,footnote #gf3 ,daly1 ,me*anism ( igne\s intrusion1 ,am4 ,j\rn4 ,sci41 ,s]4 #d1 #ae 7#aijc71 #bfi1 & lat]4 ,footnote #gg3 ,= a rec5t review 9 fav\r ( ?is !ory1 see ,loew9son ,less+1 ,! fundam5tal problems ( ,petrog5esis1 ,geol4 ,mag4 7#aiaa71 #bdh & #bhi4 ,footnote #gh3 ,d>w91 ,geological ,obs]vations on volcanic isl&s 7#ahdd71 *ap4 ,,vi4 ,footnote #gi3 ,brgg]1 ,die ,eruptivge/e9e des ,kri/ianiagebietes 7#ahid c474 ,footnote #hj3 ,h>k]1 op4 cit41 ref4 #eh1 *aps4 ,,xiii & ,,xiv4 ,footnote #ha3 ,daly1 ,orig9 ( ! alkal9e rocks1 ,bull4 ,geol4 ,soc4 ,am41 #ba 7#aiaj71 #ajh1 & ,magmatic diff]5tiation 9 ,hawaii1 ,j\rn4 ,geol41 #ai 7#aiaa71 #cji4 ,see1 h[ev]1 ,h4 ,i4 ,j5s51 z to primitive accumulation ( alkalies 9 ! upp] lay]s2 ,! di/ribution ( ,alkal9e ,rocks1 ,proc4 ,l9n4 ,soc4 ,n4 ,s4 ,w41 #cc 7#aijh71 #eba4 ,footnote #hb3 ,s*w>z1 ,causal ,geology 7#aiaj74 ,footnote #hc3 ,doelt]1 op4 cit41 ref4 #fi1 pp4 #ga-bac4 ,footnote #hd3 ,judd1 ,on ,t]ti>y gabbros c41 ,q4 ,j\rn4 ,geol4 ,soc41 #db 7#ahhf71 #ed4 ,footnote #he3 ,h>k]1 op4 cit41 ref4 #eh1 p4 #ij1 & ,nature 7,sept #aiaa71 #cai4 ,see also ,j5s51 ref4 #ha1 p4 #ebb4 ,footnote #hf3 ,dewey & ,flett1 op4 cit41 ref4 #fg1 p4 #bde4 ,footnote #hg3 ,/e9mann1 op4 cit41 ref4 #fh1 p4 #fd4 ,footnote #hh3 ,see especially ,w4 ,j4 ,sollas1 ,! volcanic di/rict ( ,c>l+=d1 ,trans4 ,r4 ,i4 ,acad41 #cj 7#ahid71 #ejb4 ,footnote #hi3 ,a4 ,geikie1 op4 cit41 ref4 #fe1 #b1 #cdd & fig4 #cdh4 ,footnote #ij3 ,brann]1 ,decomposition ( rocks 9 ,brazil1 ,bull4 ,geol4 ,soc4 ,am41 #g 7#ahif71 #bee4 ,footnote #ij3 ,maccullo*1 ,description ( ! ,we/]n ,isl&s ( ,scotl&1 #a 7#ahai71 #bfg4 ,footnote #ib3 ,= g5]al discussions ( ,metamorphic ,rocks1 see ,a4 ,delesse1 tudes sur le ,mtamorphisme des ,ro*es 7#aheh72 ,lehmann1 ,unt]su*ung5 b] die ,ent/ehung d] altkry/all9is*5 ,s*ief]ge/e9e 7#ahhd72 ,a4 ,geikie1 ,text-book ( ,geology 7#aijc71 #gfd-hjg & #gbh2 ,van ,hise1 ,a ,treatise on ,metamorphism1 ,u4 ,s4 ,geol4 ,survey1 ,mon4 #dg 7#aijd72 ,u4 ,grub5mann1 ,die kry/all95 ,s*ief]1 ed4 #b 7#aiji72 ,a4 ,geikie & o!rs1 ,! ,geological ,/ructure ( ! ,n4 ,w4 ,highl&s ( ,scotl&1 ,mem4 ,geol4 ,surv4 ,scotl& 7#aijg74 ,footnote #ic3 ,d',aubuisson de ,vois9s1 ,trait de ,geognosie 7#ahai71 #a1 #bih4 ,footnote #id3 ,d>w91 ref4 #ej4 ,footnote #ie3 ,teall1 ,metamorphosis ( ,dol]ite into ,hornbl5de-,s*i/1 ,q4 ,j\rn4 ,geol4 ,soc41 #da 7#ahhe71 #acc4 ,footnote #if3 ,t4 ,g4 ,bonney1 ,! p>5t rock ( ! diamond 9 ,s4 ,africa1 ,geol4 ,mag4 7#ahii71 #cji4 ,footnote #ig3 ,r4 ,lepsius1 ,geologie von ,deuts*l&1 #bt]4 ,teil 7#aijc71 #adf & #afi2 ,h4 ,cr$n]1 ,die ,g5esis des s*sis*5 ,granulitgebirges1 ,r5untiations-programm 7#aijf74 ,footnote #ih3 ,h>k]1 ,igne\s ,rocks ( ,skye1 ,mem4 ,geol4 ,surv4 ,scotl& 7#aijd71 #aae4 ,footnote #ii3 ,lvy1 ,excursion ,aydat1 ,bull4 ,soc4 gol4 ,france 7#ahhc71 #iaf2 ,granite de ,flamanville1 ,bull4 ,c>te gol4 ,france #e 7#ahic71 #ccg4 ,footnote #ajj3 ,f4 ,d4 ,adams1 ,haliburton & ,bancr(t areas1 ,mem4 ,geol4 ,surv4 ,canada1 ,no4 #f 7#aiaj71 #abj4 ,footnote #aja3 ,g4 ,a4 ,j4 ,cole1 ,metamorphic rocks 9 ,e4 ,tyrone & ,s4 ,donegal1 ,trans4 ,r4 ,i4 ,acad41 #ca 7#aijj71 #dec4 ,footnote #ajb3 ,w4 ,b4 ,wright & ,e4 ,b4 ,bailey1 ,geology ( ,colonsay1 ,mem4 ,geol4 ,surv4 ,scotl& 7#aiaa71 #bh4 ,footnote #ajc3 ,judd1 ,/atical & dynamical metamorphism1 ,geol4 ,mag4 7#ahhi71 #bdf4 ,footnote #ajd3 ,scrope1 op4 cit41 ref4 #fc1 p4 #bcd4 ,footnote #aje3 ,d>w91 op4 cit41 ref4 #gh1 *ap4 ,,vii4 ,footnote #ajf3 ,see especially ,j4 ,horne & ,e4 ,gre5ly1 ,foliat$ ,granites c4 9 ,e4 ,su!rl&1 ,q4 ,j\rn4 ,geol4 ,soc41 #eb 7#ahif71 #fcc4 ,footnote #ajg3 ,lawson1 ,geology ( ,ra9y ,lake ,region1 ,ann4 ,rep4 ,geol4 ,surv4 ,canada = #ahhg 7#ahhh74 ,footnote #ajh3 ,comp>e ,*amb]l9 & ,salisbury1 ,college ,text-book ( ,geology 7#aiji71 #dbh1 & o!r works by ^! au?ors4 ,footnote #aji3 ,s$]holm1 ,om granit o* gneis i ,f5nosk&ia 7) ,engli% summ>y71 ,bull4 ,comm4 gol4 ,f9l&e1 ,no4 #bc 7#aijg71 & else:]e4 ,,table ,,( ,,/ratigraphical ,,sy/ems ,quat]n>y ,gr\p ,po/-,plioc5e & ,rec5t ,ca9ozoic ,gr\p ,plioc5e ,mioc5e ,oligoc5e ,eoc5e ,mesozoic ,gr\p ,cretace\s ,jurassic ,triassic ,palozoic ,gr\p ,p]mian ,c>bonif]\s ,devonian ,gotl&ian 7 ,silurian or ,upp] ,silurian7 ,ordovician 7or ,l[] ,silurian7 ,cambrian ,pre-,cambrian ,gr\p ,,index 7,ref indicates t ! "n is quot$ 9 ! li/ ( ref]5ces1 pp4 #afb-afi47 ,acid igne\s rocks1 #abg1 #acb ,adams1 ,f4 ,d41 #abe1 ref4 #ajj ,africa1 ,s41 #adh4 ,see ,cape ( ,good ,hope & ,rhodesia4 ,agassiz1 ,a41 #be2 ,l41 #ih ,ag5ts m9ralisateurs1 #ajg ,alg1 calc>e\s1 #be ,alkal9e igne\s rocks1 #abi ,alps1 #ad1 #af1 #bc1 #ach1 #adc1 #afb ,ammonites1 #bc ,amphibole-,s*i/1 #adg ,amphibolite1 #adh ,&]son1 ,t41 #aag ,&esite1 #acc ,&russ[1 ,n41 #hd ,antrim1 ,co41 #df1 #ace ,aragonite1 deposition (1 #ag2 9 %ells1 #bb1 #hf ,armitage1 #fd ,a%1 #hh1 #aaa ,assimilation 9 igne\s rocks1 #abh ,atlantic & ,pacific types ( igne\s rocks1 #acj ,auv]gne1 #aab ,axm\?1 #df ,bact]ia1 extraction ( iron by1 #fa ,bag%ot ,hea?1 #gc ,bailey1 ,e4 ,b41 ref4 #ajb ,b&$ /ructure1 #abj ,b>rell1 ,j41 ref4 #ich ,b>rois1 ,c41 #abe ,b>ytes 9 s&/one1 #fb ,basalt1 #acb1 #ace ,basic igne\s rocks1 #abg1 #acb ,ba?olites1 #abc ,bav>ia1 dolomites (1 #cb ,belemnites1 #bc ,black ,sea1 #ag1 #hd ,bohemia1 #acd1 #aeh ,bonney1 ,t4 ,g41 ref4 #if ,b\ld]-clay1 #if ,b\rnes1 #dc ,bra*iopods1 #bd ,brann]1 ,j4 ,c41 #adj ,brazil1 #hh1 #adj ,breccia1 #ee ,brgg]1 ,w4 ,c41 #abe1 #abh ,brongni>t1 ,a41 #b ,buns51 ,r4 ,w41 #abg ,cad] ,idris1 #adc ,calc>e\s ,tufa1 #ad1 #af ,canada1 #ajc1 #aej1 #aeh ,caons ( ,arizona1 #dg ,cape ( ,good ,hope1 #af1 #da1 #ei1 #fc1 #ajc1 #aba1 #acf1 #aef ,causses1 #de1 #dh1 #ej ,cayeux1 ,l41 #ci ,cephalopods1 #bc ,*alk1 #bj1 #db ,*amb]l91 ,t4 ,c41 #abi ,*>a-lime/one1 #ai ,*$d>1 #dh ,*]t1 #dj1 #fb ,*9a-clay1 #hf ,*ri/iania di/rict1 #abe1 #abh ,*ri/mas ,isl&1 #cg ,cl>e1 ,co41 #df ,clay1 #gh ,cleavage1 #hi ,close1 ,maxwell ,h41 #ih ,cole1 ,g4 ,a4 ,j41 #aag1 refs4 #h1 #ge & #aja ,coleman1 ,a4 ,c41 #ajc ,colonsay1 #aeb ,column> /ructure1 #aae ,composite gneiss1 #abb1 #aec ,cones1 volcanic1 #aab1 #acc ,conglom]ates1 #gj ,connem>a m>ble1 #cf ,contact metamorphism1 #add ,conybe>e1 ,w4 ,d41 #ce ,coral-reefs1 #be2 silicification 91 #dj ,cordi]1 ,p4 ,l4 ,a41 #c ,cork m>ble1 #ed ,cr$n]1 ,h41 #abe1 #adi ,cr9oidal lime/one1 #bd ,cross1 ,w41 ref4 #ei ,cru%-conglom]ates1 #bh ,cry/allisation 9 igne\s rocks1 #ajg ,dale1 ,t4 ,n41 ref4 #ec ,daly1 ,r4 ,a41 #ah1 #cc1 #abe1 #abg1 #abh ,dana1 ,j4 ,d41 #cj ,d>w91 ,c41 #be1 #ij1 #abh1 #ade1 #aef ,daubre1 ,a41 #ff ,d',aubuisson de ,vois9s1 #ade ,david1 ,t4 ,w4 ,e41 ref4 #eg ,d$olomitisation1 #ce ,de la ,be*e1 ,h41 #ah ,delesse1 ,a41 ref4 #ib ,d]by%ire1 #dh1 #gc1 #ig ,des]t s&s1 #fh1 #ga ,dewey1 ,h41 #aag1 #acj ,diatoms1 #dj ,diff]5tiation 9 igne\s rocks1 #abh ,d9>ic ,alps1 #af1 #bc1 #eb ,diorite1 #acb ,doelt]1 ,c41 #ah1 #ca1 #abe1 #acj1 #aed ,dol]ite1 #acb ,dol9as1 #ej ,dolomite1 #ab1 #bf1 #bi1 #cj ,donegal1 ,co41 #acg1 #aej1 #aec ,d[n1 ,co41 #gd1 #acg ,dreikant]1 #ga ,druml9s1 #ih1 #ajb ,durham1 dolomite (1 #ce ,duro*]1 ,j41 #abg ,dwyka ,conglom]ate1 #ajc ,dykes1 #aaj1 #aah1 #acg ,dynamo-metamorphism1 #add ,eclogite1 #adh ,ed9burgh1 #adc ,egypt1 #bb1 #fd1 #fh ,ehr5b]g1 ,c4 ,g41 #e1 #bj ,epidiorite1 #adg ,eurite1 #acb ,eutectic proportion1 #aji ,exfoliation ( granite1 #adj ,felsitic /ructure1 #ajh ,f]romagnesian m9]als1 #aji ,fiji ,is41 #dj ,f+al's ,cave1 #aaf ,f9l&1 #aei ,flag/ones1 #fi ,flett1 ,j4 ,s41 #aag1 #acj ,fl9t1 #ch1 #fb2 gravels1 #gd ,flocculation ( clay1 #hj ,fl[-cleavage1 #ib ,fluidal /ructure1 #abj ,foliation1 #ij1 #ade ,=am9if]a1 #bj ,=ehamm]1 ,g41 #bi ,fracture-cleavage1 #ib ,fre%wat] molluscs1 #bc ,fuji-yama1 #acd ,funafuti atoll1 #ai1 #bf ,fundam5tal gneiss1 #aeh ,fusul9a lime/one1 #ba ,gabbro1 #acb1 #adb ,g>d9]1 ,c41 #bi ,g>wood1 ,e4 ,j41 #ce ,geikie1 ,a41 #aag1 #ach1 #adb ,giant's ,causeway1 #aaf ,gilb]t1 ,g4 ,k41 #abc ,glacial gravels1 #ih ,glaci]s1 arctic1 #ih ,glassy igne\s rocks1 #aaj ,glauconite 9 *alk1 #bj ,globig]9a-ooze1 #bj ,gneiss1 #abb1 #aeb1 #aeh1 #afa ,gordon1 ,m4 ,ogilvie1 #bg ,granite1 #acb1 #ach ,granodiorite1 #acb ,great ,salt ,lake1 ,utah1 #ae ,great ,:9 ,sill1 #acf ,gre5ly1 ,e41 ref4 #ajf ,gregory1 ,j4 ,w41 #aag ,greywacke1 #eh ,grund1 ,a41 #ej ,guppy1 ,h4 ,b41 #dj ,halim$a1 #ai1 #bi ,hall1 ,a4 ,d41 #ha ,h>k]1 ,a41 #hi1 #ajg1 #abe1 #abh1 #acj1 #adi ,h>le* ,b$s1 #gd ,hawaii1 #ajf ,hawes1 ,g4 ,v41 #abf ,hebrides1 #aaf1 #ace1 #aeb1 #afa ,hegau1 !1 #ace ,h5ry ,m\nta9s1 ,utah1 #abc ,h]cegov9a1 k>/l&1 #ad1 #eb ,highl&s ( ,scotl&1 #gf1 #adc1 #afa ,h9de1 ,g4 ,j41 #ch1 #fb ,holl&1 ,p41 #hc1 #ij ,hornbl5de-,s*i/1 #adg ,horne1 ,j41 ref4 #ajf ,horwood1 ,a4 ,b41 ref4 #h ,h[e1 ,j4 ,a41 #ac ,hutton1 ,j41 #da1 #ajd1 #abb1 #aeh ,hydrozoa1 #be ,idd+s1 ,j4 ,p41 #ajh1 #aae1 #abe1 ref4 #ei ,igne\s ,rocks1 #ajc ,india1 #adj ,int]m$iate igne\s rocks1 #abg1 #acb ,intrusion ( igne\s rocks1 #abd ,intrusive %eets1 #abb1 #acf ,iri% ,*annel1 lime/one 91 #ag ,iron-bact]ia1 #fa ,iron ,pyrites 9 muds1 #he ,jajce1 #af ,j5s51 ,h4 ,t41 ref4 #ha ,judd1 ,j4 ,w41 #f1 #db1 #fh1 #ajd1 #acj1 #aed ,jukes-,br[ne1 ,a41 #dj ,jura ,mts41 #df ,kalah>i des]t1 #da1 #fc ,kaol91 #hg ,k>lsbad1 #ad ,k>/1 #di ,katz]1 ,f41 #af ,k]ry1 #gf ,klem5t1 ,c41 #ca ,knoll /ructure1 #bh ,laccolites1 #abc ,lacroix1 ,a41 #ae1 #abe1 #aej ,lake1 ,p41 #gf ,lamellibran*s1 #bb ,lamplugh1 ,g4 ,w41 #hi ,l&slips1 #df1 #id ,lapwor?1 ,c41 ref4 #ci ,lat]isation1 #fd ,laur5tian gneiss1 #aeh ,laut>et ,pass1 #ie ,lava-fl[s1 #aac ,lava-pla9s1 #aad ,lawson1 ,a4 ,d41 #abe1 #aeh ,lehmann1 ,j41 #aeg ,le9/] granite1 #adc ,lei?1 ,c4 ,k41 #hi ,lei? ,hill1 #gc ,leonh>d1 ,k4 von1 #c ,lepsius1 ,r41 #abe1 ref4 #ig ,less+1 ,l41 ref4 #gg ,lvy1 ,m41 #f1 #abe1 #aej1 #aef ,lime/ones1 #ab1 #aej2 deposit$ f solution1 #ad2 organic1 #ai ,l9ck1 ,g41 #af1 #ah1 #fa ,lit-p>-lit injection1 #aeg ,li?oidal /ructure1 #ajh ,li?o?amnium1 #bj1 #bi ,little1 ,o4 ,h41 ref4 #h ,llanb]is1 #if ,loam1 #hb ,londond]ry1 ,co41 #ace ,loss51 ,k4 ,a41 #aeg ,l[] ,gre5s&1 #fb1 #gc ,lundy ,id41 #aci ,lyons1 ,h4 ,g41 #fc ,maccullo*1 ,j41 #adb ,magmas1 igne\s1 #abg ,magmatic diff]5tiation1 #abh ,magnesian lime/one1 #ce ,magnesium 9 organic skeletons1 #bi ,m>ble1 #cf1 #ed1 #aej ,m>l1 #hc ,m>tel1 ,e4 ,a41 #eb ,matopo ,hills1 #adj ,matt]horn1 #adc ,metamorphic ,rocks1 #adc ,mica-,s*i/1 #adg1 #afa ,millepora1 #be ,mill]sdale1 #dh ,m9]als1 #f1 #h ,mojsisovics1 ,e41 #bg ,monaghan1 ,co41 #gd ,mont ,blanc1 #ach1 #adc ,mont ,g5vre1 #aag ,mull1 #ace ,murray1 ,j41 #be ,nagelfluh1 #ad ,new ,=e/1 #gd ,nor?umb]l&1 #acf ,norway1 #afb ,nubian ,s&/one1 #fc ,nummulitic lime/one1 #ba ,obsidian1 #acb ,old ,r$ ,s&/one1 #ge ,oolitic gra9s1 #ae1 #ag ,oolitic ,lime/one1 #ah1 #dj ,ophicalcite1 #cf ,ord] ( cry/allisation ( m9]als1 #ajh ,ox ,m\nta9s1 #aeh ,p>is bas91 #dj1 #gd ,petrographical prov9ces1 #acj ,pfaff1 #cj1 #cd ,phillips1 ,j4 ,a41 #fd1 #fg ,phillips1 ,w41 #ce ,phosphatic lime/one1 #cf ,phosphorites du ,qu]cy1 #cg ,pill[-/ructure1 #aag ,pipe-clay1 #gh ,pisolite1 #ae1 #ah ,planetesimal !ory1 #abi1 #acj1 #aei ,plutonic conditions1 #aai ,porosity ( s&/one1 #ff2 ( clay1 #gi ,porphyritic /ructure1 #aai ,portl& /one1 #ah ,portrane1 ref4 #aa ,purbeck ,m>ble1 #ed ,pyrox5ite1 #adh ,qu>tz ve9s1 #ef1 #fe ,qu>tz-felsite1 #acb ,qu>tzite1 #fc1 #gf1 #aea1 #afa ,qu>tz-porphyry1 #acb ,radiol>ia1 #dj1 #aah ,rav9es 9 lime/one1 #dh ,reade1 ,t4 ,m41 #hc1 #ij ,r$ ,clay ( deep seas1 #hh ,regional metamorphism1 #aeg ,reynolds1 ,s4 ,h41 #bi ,rhodesia1 #adj ,rhyolite1 #acb ,ri*?(51 ,f4 von1 #be1 #bg ,ripple-m>ks1 #fi ,rock1 def9ition (1 #g ,roe/one1 #ae ,rog]s1 ,a4 ,w41 #da1 #fb1 #fc ,ros5bus*1 ,h41 #f1 ref4 #eh ,ro?pletz1 ,a41 #bg ,russell1 ,e41 #hb ,russell1 ,i41 ref4 #ef ,samoa1 #aag ,s&-dunes1 #fb1 #fi ,s&-rock1 #fe ,s&s1 orig91 #ef2 cem5t+ (1 #fj2 gra9s1 #ff ,s&/ones1 #ef2 cry/all9e1 #fd ,saxony1 #adh1 #adi1 #aeh ,sea1 action ( on %ore1 #eh1 #hg2 calcium c>bonate 91 #af ,se>le1 ,a4 ,b41 ref4 #ici ,s$]holm1 ,j4 ,j41 #abe1 #aei ,semp]1 ,k41 #be ,s]p5t9e1 #acc ,s*i/s1 #ade1 #afa ,s*w>z1 ,e4 ,h4 ,l41 #abi ,scori1 #aab ,scoriace\s /ructure1 #ajf ,scrope1 ,g4 ,p41 #ajd1 #aaf1 #ade1 #aef ,%ale1 #hc1 #if2 col\rs (1 #he ,%>pe1 ,d41 #hi ,%ell-m>l1 #bc ,silicates 9 igne\s rocks1 #aji ,silicifi$ wood1 #fd ,sills1 igne\s1 #acf ,skeats1 ,e4 ,w41 #cj1 #ca1 #ce ,skye1 #ace1 #ach1 #adb1 #adi ,slate1 #hh1 #if ,smi?1 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