,transcrib]'s ,note ,emphasiz$ text d5ot$ z ,italic & ,bold respectively4 ,cambridge ,natural ,sci5ce ,manuals4 ,geological ,s]ies4 ,,! ,,pr9ciples ,,( ,,/ratigraphical ,,geology ,london3 ,c4 ,j4 ,,clay ,,& ,,sons1 ,,cambridge ,,univ]sity ,,press ,,w>eh\se1 ,,ave ,,m>ia ,,lane4 ,,& ,h4 ,k4 ,,lewis1 #acf1 ,,g[] ,,/reet1 ,w4,c4 ,illu/ration ,leipzig3 ,f4 ,a4 ,,brockhaus4 ,new ,york3 ,,! ,,macmillan ,,company4 ,bombay3 ,e4 ,,seym\r ,,hale4 ,,! ,,pr9ciples ,,( ,,/ratigraphical ,,geology ,,by ,j4 ,e4 ,,m>r1 ,m4,a41 ,f4,r4,s4 ,,fell[ ,,& ,,lectur] ,,( ,s4 ,,john',s ,,college1 ,,cambridge1 ,,& ,,univ]sity ,,lectur] ,,9 ,,geology4 ,,cambridge3 ,,at ,,! ,,univ]sity ,,press4 #ahih ,all ,rights res]v$4 ,cambridge3 ,,pr9t$ ,,by ,j4 ,c4 ,f4 ,,clay1 ,,at ,,! ,,univ]sity ,,press4 ,,preface4 ,! pres5t "w has be5 writt5 9 ord] t /ud5ts may ga9 by its p]usal "s idea ( ! me?ods & scope ( ,/ratigraphical ,geology4 ,i believe t ?is idea c be obta9$ mo/ satisfactorily1 if a l>ge numb] ( ! details connect$ ) ! /udy ( ! /ratifi$ rocks are omitt$1 & ,i h accord+ly giv5 v brief acc\nts ( ! /rata ( ! diff]5t ,sy/ems4 ,! "w is int5d$ = use 9 conjunction ) any book :i* treats ( ! /rata ( ! ,geological ,column at consid]able l5g?2 "s ( ^! books are m5tion$ on pages #abd1 #abe4 ,j4 ,e4 ,m4 ,cambridge1 ,novemb]1 #ahih4 ,,cont5ts4 ,,page ,,*apt] ,i4 ,introduction #a ,,*apt] ,,ii4 ,acc\nt ( ! gr[? & progress ( /ratigraphical geology #f ,,*apt] ,,iii4 ,nature ( ! /ratifi$ rocks #ba ,,*apt] ,,iv4 ,! law ( sup]position #ca ,,*apt] ,v4 ,! te/ ( includ$ organisms #dj ,,*apt] ,,vi4 ,me?ods ( classification ( ! /rata #eh ,,*apt] ,,vii4 ,simulation ( /ructures #gb ,,*apt] ,,viii4 ,geological maps & sections #hd ,,*apt] ,,ix4 ,evid5ces ( conditions "u :i* /rata 7 =m$ #ig ,,*apt] ,x4 ,evid5ces ( conditions "u :i* /rata 7 =m$1 cont9u$ #aaf ,,*apt] ,,xi4 ,! classification ( ! /ratifi$ rocks #abe ,,*apt] ,,xii4 ,! ,precambrian rocks #acb ,,*apt] ,,xiii4 ,cycles ( *ange 9 ! ,briti% area #adi ,,*apt] ,,xiv4 ,! ,cambrian sy/em #aeb ,,*apt] ,,xv4 ,! ,ordovician sy/em #afd ,,*apt] ,,xvi4 ,! ,silurian sy/em & ! *anges :i* occurr$ 9 ,brita9 at ! close ( ,silurian times #agd ,,*apt] ,,xvii4 ,! ,devonian sy/em #ahc ,,*apt] ,,xviii4 ,! ,c>bonif]\s sy/em #aib ,,*apt] ,,xix4 ,! *anges :i* occurr$ dur+ ! ?ird cont95tal p]iod 9 ,brita92 & ! =eign ,p]mo-,c>bonif]\s rocks #bjb ,,*apt] ,,xx4 ,! ,p]mian sy/em #bji ,,*apt] ,,xxi4 ,! ,triassic sy/em #bah ,,*apt] ,,xxii4 ,! ,jurassic sy/em #bbf ,,*apt] ,,xxiii4 ,! ,cretace\s sy/em #bcf ,,*apt] ,,xxiv4 ,! ,eoc5e rocks #bdd ,,*apt] ,,xxv4 ,! ,oligoc5e & ,mioc5e p]iods #bea ,,*apt] ,,xxvi4 ,! ,plioc5e b$s #bef ,,*apt] ,,xxvii4 ,! ,plei/oc5e accumulations #bfj ,,*apt] ,,xxviii4 ,! ,/eppe p]iod #bfg ,,*apt] ,,xxix4 ,! ,=e/ p]iod #bge ,,*apt] ,,xxx4 ,rem>ks on v>i\s que/ions #bgh ,,add5da ,,et ,,corrig5da4 ,,tn3 ,corrections made6 p4 #ch1 l9e #ae f bottom3 = 'jo9+' read 'jo9t+' p4 #bjh1 l9e #f f bottom3 = ',dr' read ',messrs ,m$licott &' p4 #bad1 l9e #ae f bottom3 aft] ',p]mo-,c>bonif]\s ,/rata' ins]t '?r\gh ! ,p]mian' p4 #bag1 la/ l9e ( footnote3 = ',dr' read ',messrs ,m$licott &' ins]t a second footnote3 ',= in=mation conc]n+ ! ,p]mian volcanic rocks see ,sir ,a4 ,geikie's ,anci5t ,volcanoes ( ,great ,brita94' p4 #bce1 ins]t a footnote3 ',a good acc\nt ( ! ,briti% ,jurassic rocks w be f\nd 9 ,mr ,h4 ,b4 ,woodw>d's ,memoir on ,! ,jurassic ,rocks ( ,brita94 ,mem4 ,geol4 ,survey1 #ahic--4' p4 #bej1 top l9e3 = ',g>d9]' read ',g>dn]' ,,*apt] ,i4 ,,introduction4 ,x is ! aim ( ! ,/ratigraphical ,geologi/ to record ! ev5ts :i* h occurr$ dur+ ! exi/5ce ( ! e>? 9 ! ord] 9 :i* !y h tak5 place4 ,he tries to re/ore ! physical geography ( ea* p]iod ( ! pa/1 & 9 ?is way to write a connect$ hi/ory ( ! e>?4 ,8 me?ods are 9 a g5]al way simil> to ^? ( ! e?nologi/1 ! ar*ologi/1 & ! hi/orian1 & he is confront$ ) difficulties resembl+ ^? :i* att5d ! rese>*es ( ! /ud5ts ( human hi/ory4 ,=emo/ among/ ^! difficulties is t due to ! imp]fection ( ! geological record1 b simil> difficulty is felt by ^? :o pursue ! /udy ( o!r unc]ta9 sci5ces1 & :il/ ?is imp]fection is v pat5t to ! geologi/1 x is p]haps unduly exagg]at$ by ^? :o h only a g5]al k ( ! pr9ciples & aims ( geology4 ,! hi/ory ( ! e>?1 l o!r hi/ories1 is a connect$ "o1 9 :i* "o p]iod is l9k$ on to ! next4 ,?is 0 n always suppos$ to be ! case2 ! cata/rophic geologi/ ( bygone times believ$ t aft] ea* great geological p]iod a convulsion ( nature left ! e>?'s cru/ z a tabula rasa on :i* a new set ( records 0 engrav$1 hav+ no connexion ) ^? :i* _h be5 de/roy$4 ,c>eful /udy ( ! records ( ! rocks has prov$ t ! conclusions ( ! cata/rophi/s 7 errone\s1 & t ! ev5ts ( "o p]iod produce _! impression ^u ! hi/ory ( ! next4 ,e ev5t :i* occurs1 h[ev] insignificant1 introduces a new complication into ! conditions ( ! e>?1 & accord+ly ^? conditions are nev] q ! same4 ,al?\gh ! *anges 7 no d\bt v sl[1 s t ! same g5]al conditions may be trac$ z exi/5t dur+ two successive p]iods1 m9or complications occurr$ 9 ! inorganic & organic worlds1 & we nev] get an exact recurr5ce ( ev5ts4 ,vegetable deposits may n[ be 9 process ( accumulation :i* 9 ages to come may be conv]t$ into coal1 b ! g5]al conditions :i* 7 preval5t dur+ t ,c>bonif]\s p]iod :5 mo/ ( our workable coal 0 deposit$ d n n[ exi/1 & w nev] exi/ aga94 ,! *anges :i* h tak5 place & :i* are tak+ place %[ an advance f ! simple to ! m complex1 & ! /ratigraphical geologi/ is confront$ ) a problem to :i* ! key is developm5t1 & x is 8 task to trace ! developm5t ( ! e>? f ! primitive /ate to ! complex condition 9 :i* we f9d x at ! pres5t day4 ,our g5]al ignorance ( ! ev5ts ( ! e>lie/ p]iods ( ! hi/ory ( ! e>? w be emphasis$ 9 ! sequel1 & x w be f\nd t ! complexity :i* m>ks ! inorganic & organic conditions :i* exi/$ dur+ ! deposition ( ! e>lie/ rocks ( :i* we h detail$ k po9ts to ! lapse ( enorm\s p]iods ( "t subsequ5t to ! =mation ( ! e>?1 & previ\s to ! deposition ( ^? rocks4 ,! imp]fection ( ! record is mo/ pron\nc$ = t long p]iod ( "t1 b 9 ?is respect ! geologi/ is 9 ! same condition z ! /ud5t ( human hi/ory1 = ! relics ( ! e>ly /one age prove t man 9 t age _h atta9$ a fairly high /ate ( civilisation1 & ! gap :i* sep>ates paloli?ic man f ! fir/ ( our race is relatively speak+ z great z t :i* divides ! ,cambrian p]iod f ! comm5cem5t ( e>?-hi/ory4 ,nev]!less1 human hi/ory is a sci5ce :i* has made gigantic /rides t[>ds ! solution ( _m problems connect$ ) ! developm5t ( man & civilisation1 & simil>ly geology has advanc$ "s way 9 its task ( elucidat+ ! hi/ory ( our globe4 ,! task ( ! /ratigraphical geologi/ is two-fold4 ,9 ! fir/ place1 he mu/ e/abli% ! ord] ( succession ( ! /rata1 = a correct *ronology is ( p>am\nt importance to ! /ud5t ( e>?-lore4 ,! precautions :i* mu/ be tak5 9 mak+ out ! ord] ( deposition ( ! rocks ( any area1 & correlat+ ^? ( "o area ) ^? ( ano!r w be consid]$ 9 ! body ( ! "w4 ,:5 ?is task is complet$1 !re yet rema9s ! c>eful exam9ation ( all ! in=mation suppli$ by a /udy ( ! rocks ( ! cru/1 9 ord] to asc]ta9 ! actual conditions :i* exi/$ dur+ ! deposition ( any /ratum or gr\p ( /rata4 ,9 practice1 x is g5]ally v difficult to sep>ate ^! two dep>tm5ts ( ! lab\r ( ! /ratigraphical geologi/1 & ! two k9ds ( "w are (t5 done to a l>ge ext5t simultane\sly1 or sometimes alt]nately4 ,frequ5tly ! g5]al succession ( ! deposits compris+ an important gr\p is asc]ta9$1 & at ! same "t obs]vations made conc]n+ ! physical *>act]s ( ! deposits & ! nature ( _! includ$ organisms1 :i* are suffici5t to af=d "s insight into ! g5]al hi/ory ( ! p]iod :5 ^! deposits 7 laid d[n2 a m detail$ classification ( ! same set ( deposits may be subsequ5tly made1 & z ! result ( ?is1 m m9ute obs]vations z to ! v>iations 9 ! physical & biological conditions ( ! p]iod are possible1 :i* p]mit u to write a mu* m concise hi/ory ( ! p]iod4 ,s great has be5 ! t5d5cy to c>ry on "w 9 a m & m detail$ mann]1 t x is v difficult if n impossible to tell :5 any approa* to f9ality is rea*$ 9 ! /udy ( a gr\p ( /rata 9 any area4 ,r\ghly speak+1 we may /ate t our k ( a gr\p ( /rata is obta9$ by ?ree processes1 or r modifications ( "o process4 ,! g5]al ord] ( succession is e/abli%$ by ! pione]1 frequ5tly z ! result ( "w c>ri$ on ?r\gh "o or two seasons4 ,subsequ5tly to ?is1 a m m9ute subdivision ( ! rocks is possible z ! result ( lab\rs conduct$ by "o or m work]s :o are enabl$ to avail !mselves ( ! "w ( ! pione]1 & our k ( ! rocks is l>gely increas$ !reby4 ,b ! m9uti1 (t5 ( prime importance1 are suppli$ by work]s :o mu/ sp5d a l>ge portion ( _! "t 9 ! area :]e ! "w lies1 & x is only 9 di/ricts :]e "w ( ?is "* has be5 p]=m$1 t our k ( ! /rata approa*es completion4 ,! /rata ( ! ,arctic regions1 = example1 h 9 _m places be5 exam9$ by pione]s1 b a great deal rema9s to be done 9 ^? regions2 ! ma9 subdivisions only h be5 def9$ 9 _m cases1 & our in=mation conc]n+ ! physical hi/ory ( ,arctic regions 9 pa/ times is comp>atively meagre4 ,to come ne>] home--a few miles nor? ( ,cambridge lies ! little pat* ( ,corallian rock at ,upw>e2 x has be5 frequ5tly visit$1 & a l>ge suite ( organic rema9s extract$ f x1 b no "o has devot$ ! "t to ! collection ( rema9s f ?is deposit :i* has be5 devot$ to t ( "s o!r =mations pres5tly to be m5tion$1 & accord+ly our k ( ! fauna ( t deposit is f> f complete4 ,contra/ ) ?is ! in=mation we possess ( ! little seam kn[n z ! ,cambridge ,gre5s&1 f :i* organic rema9s h be5 s$ul\sly collect$ dur+ ! ext5sive op]ations :i* h be5 c>ri$ on = ! extraction ( ! phosphatic nodules :i* occur 9 ! seam4 ,! suite ( relics ( ! organisms ( t p]iod is accord+ly f> m p]fect ?an 9 ! case ( _m o!r b$s1 & inde$ ! l>ge & v>i$ collection ( relics ( ! v]tebrata ( ! p]iod :i* furni% mu* in=mation ( value to ! palontologi/ w\ld n h be5 ga!r$ toge!r1 _h n ?is seam be5 s c>efully work$1 & an important p>agraph 9 ! *apt] be>+ on ! hi/ory ( ?is p]iod w\ld h rema9$ unkn[n to u4 ,aga91 two little pat*es ( lime/one ( ! same age1 "o 9 c5tral ,engl& & ! o!r 9 ! isl& ( ,go?l&1 h be5 ! objects ( s$ul\s inquiry by local obs]v]s1 & we f9d aga9 t our k ( ! physical hi/ory ( ! p]iod1 z reg>ds ^! two regions1 is exceptionally p]fect4 ,special /ress is laid ^u ?is po9t1 = 9 ^! days1 :5 e c\nty possesses its le>n$ societies ^: memb]s are desir\s ( advanc+ 9 e possible way ! progress ( sci5ce1 x is well to insi/ ^u ! importance ( ?is detail$ "w :i* c only be done by ^? :o h a l>ge am\nt ( "t to devote to ! rigor\s exam9ation ( ! rocks ( a limit$ area4 ,,*apt] ,,ii4 ,,acc\nt ,,( ,,! ,,gr[? ,,& ,,progress ,,( ,,/ratigraphical ,,geology4 ,! hi/ory ( ! gr[? ( a sci5ce is n always treat$ z an ess5tial "p ( our k ( t sci5ce1 & _m text-books b>ely allude to ! pa/ progress ( ! sci5ce ) :i* !y deal4 ,! importance ( a review ( pa/ progress has1 h[ev]1 attract$ ! att5tion ( _m geologi/s1 & ,sir ,*>les ,lyell1 9 8 ,pr9ciples ( ,geology1 gave prom95ce to an hi/orical sket* ( ! rise & progress ( ! sci5ce4 ,hi/orical /udies ( ?is nature h m ?an an academic value2 ! v errors made by m5 9 pa/ times are useful z w>n+s to prev5t ^? ( ! pres5t day f go+ a/ray2 ! l9es along :i* a sci5ce has progress$ 9 ! pa/ may (t5 be us$ z guides to indicate h[ "w is to be conduct$ 9 ! future2 b p]haps ! greate/ lesson :i* is taught by a c>eful consid]ation ( ! rise & progress ( a /udy is "o :i* has a moral value1 = he :o pays att5tion to ! gr[? ( 8 sci5ce 9 pa/ times1 ga9s a rev]5ce = ! old ma/]s1 & at ! same "t le>ns t a slavi% reg>d = au?ority is a dang]\s ?+4 ,?is is a lesson :i* is ( ! utmo/ importance to ! /ud5t :o wi%es to advance 8 sci5ce1 & w prev5t him f pay+ too little att5tion to ! "w ( ^? :o h gone be=e him1 :il/ x w enable him to p]ceive t z great m5 h fall5 into error ?r\gh n hav+ suffici5t data at _! disposal1 he ne$ n be unduly tr\bl$ %\ld he f9d t conclusions :i* he has lawfully atta9$ aft] consid]ation ( evid5ce unkn[n to 8 pr$ecessors cla% ) ^? :i* !y adopt$4 ,want ( ?is hi/oric k has no d\bt caus$ _m work]s to wa/e _! "t on "w :i* has already be5 p]=m$1 b x has also l$ o!rs to )hold important conclusions f _! fell[-work]s because !y 7 suppos$ to be het]odox4 ,9 an unc]ta9 sci5ce l geology "o ( ! great difficulties is to keep an ev5 balance betwe5 contempt & undue respect = au?ority1 & assur$ly a sci5tific /udy ( ! pa/ hi/ory ( a sci5ce w d mu* to enable a /ud5t to atta9 ?is end4 ,x w be useful1 !re=e1 at ?is po9t to give a brief acc\nt ( ! rise & progress ( ! /udy ( /ratigraphical geology1 s f> z t c be done )\t ent]+ into te*nical details1 at ! same "t recomm5d+ ! /ud5t to survey ! progress ( ?is bran* ( our sci5ce = himself1 aft] he has ma/]$ ! pr9ciples ( ! subject1 & su* details z are ! prop]ty ( all :o h /udi$ ! sci5ce f ! v>i\s text-books writt5 = advanc$ /ud5ts4 ,william ,smi?1 ! ',fa!r ( ,engli% ,geology1' is rightly reg>d$ z ! f\nd] ( /ratigraphical geology on a true sci5tific basis1 b l all great discov]]s1 8 "w 0 =e%ad[$ by o!rs1 ?\gh s dimly1 t ?is does n & _c detract f 8 fame4 ,x is desirable1 h[ev]1 to beg9 our hi/orical review at a "t some:at fur!r back ?an t at :i* ,smi? gave to ! _w 8 epo*-mak+ map & memoirs4 ,be=e ! eighte5? c5tury1 /ratigraphical geology _c be said to h exi/$ z a bran* ( sci5ce--! way _h n be5 prep>$ = x4 ,data _h be5 accumulat$ :i* w\ld h be5 invaluable if at ! disposal ( op5-m9d$ philosoph]s1 b ) few exceptions prejudice prev5t$ ! tru? f becom+ kn[n4 ,!re 7 two great /umbl+-blocks to ! e/abli%m5t ( a def9ite sy/em ( /ratigraphical geology by ! writ]s ( ! ,middle ,ages1 fir/ly1 ! cont5tion t fossils 7 n ! relics ( organisms1 &1 secondly1 :5 x 0 conc$$ t !y repres5t$ portions ( organisms :i* _h once exi/$1 ! ass]tion t !y _h rea*$ _! pres5t positions out ( rea* ( ! sea dur+ ! ,noa*ian ,deluge4 ,= full details conc]n+ ! mis*iev\s effects ( ^! t5ets ^u ! sci5ce ! read] is ref]r$ to ! lum9\s sket* ( ! gr[? ( geology 9 ! fir/ f\r *apt]s ( ,sir ,*>les ,lyell's ,pr9ciples ( ,geology4 ,! disposition ( rocks 9 /rata1 & ! occurr5ce ( diff]5t fossils 9 diff]5t /rata1 0 kn[n to ,woodw>d :5 he publi%$ 8 ,essay t[>d a ,natural ,hi/ory ( ! ,e>? 9 #afie1 & ! valuable collections made by ,woodw>d & n[ deposit$ 9 ! ,woodw>dian ,museum at ,cambridge1 %[ h[ fully he appreciat$ ! importance ( ^! facts1 ?\gh he =m$ v errone\s conclusions f !m1 ow+ to ! mann] 9 :i* he drew ^u 8 imag9ation :5 facts fail$ him1 ma9ta9+ t fossils 7 deposit$ 9 ! /rata accord+ to _! gravity1 ! heavie/ s9k+ fir/1 & ! lighte/ la/1 dur+ ! "t ( ! univ]sal deluge4 ,! foll[+ extracts f ,"p ,,ii4 ( ,woodw>d's book1 %[ ! position 9 :i* our k ( ! /rata /ood at ! end ( ! sev5te5? c5tury3 ,! ,matt]1 subsid+ 4441 =m$ ! ,/rata ( ,/one1 ( ,m>ble1 ( ,cole1 ( ,e>?1 & ! re/2 ( :i* ,/rata1 ly+ "o ^u ano!r1 ! ,t]re/rial ,globe1 or at lea/ z mu* ( x z is ev] display$ to view1 do? ma9ly consi/4444 ,! ,%ells ( ^? ,cockles1 ,escalops1 ,p]ew9kles1 & ! re/1 :i* h a great] degree ( ,gravity1 7 enclos$ & lodg$ 9 ! ,/rata ( ,/one1 ,m>ble1 & ! heavi] k9ds ( ,t]re/rial ,matt]3 ! light] ,%ells n s9k+ d[n till aft]w>ds1 & s fall+ among/ ! light] ,matt]1 su* z ,*alk1 & ! l 444 accord+ly we n[ f9d ! light] k9ds ( ,%ells1 su* z ^? ( ! ,e*9i1 & ! l1 v pl5tifully 9 ,*alk4444 ,humane ,bodies1 ! ,bodies ( ,quadrup$s1 & o!r ,l&-,animals1 ( ,birds1 ( ,fi%es1 bo? ( ! ,c>tilag9\s1 ! ,squamose1 & ,cru/ace\s k9ds2 ! ,bones1 ,tee?1 ,horns1 & o!r p>ts ( ,bea/s1 & ( ,fi%es3 ! ,%ells ( ,l&-,snails3 & ! ,%ells ( ^? ,riv] & ,sea ,%ell-,fi% t 7 light] ?an ,*alk c4 ,trees1 ,%rubs1 & all o!r ,vegetables1 & ! ,se$s ( !m3 & t peculi> ,t]re/rial ,matt] :]e( ^! consi/1 & out ( :i* !y are all =m$1 444 7 n precipitat$ till ! la/1 & s lay above all ! =m]1 con/itut+ ! supreme or outmo/ ,/ratum ( ! ,globe4444 ,! said ,/rata1 :e!r ( ,/one1 ( ,*alk1 ( ,cole1 ( ,e>?1 or :atev] o!r ,matt] !y consi/$ (1 ly+ ?us ea* ^u o!r1 7 all orig9ally p>allel3 444 !y 7 pla91 eav51 & regul>4444 ,aft] "s "t ! ,/rata 7 brok51 on all sides ( ! ,globe3 444 !y 7 dislocat$1 & _! ,situation v>i$1 be+ elevat$ 9 "s places1 & depress$ 9 o!rs 444 ! ,ag5t1 or =ce1 :i* effect$ ?is ,disruption & ,dislocation ( ! ,/rata1 0 seat$ )9 ! ,e>?4 ,woodw>d's writ+s no d\bt ex]cis$ a direct influ5ce on ! gr[? ( our subject1 b ! indirect effects ( 8 munific5t beque/ to ! ,univ]sity ( ,cambridge & 8 f\ndation ( ! ,*air ( ,geology 9 t ,univ]sity 7 ev5 great]1 = z w be po9t$ out 9 its prop] place1 two ( ! occupants ( t *air play$ a consid]able "p 9 rais+ /ratigraphical geology to ! position :i* x n[ occupies4 ,! discov]ies :i* 7 made aft] ! publication ( ,woodw>d's book & be=e ! appe>ance ( ! map & writ+s ( ,william ,smi? are giv5 9 ! memoir ( ! latt] au?or1 writt5 by 8 nephew1 :o =m]ly occupi$ ! ,*air ( ,geology at ,ox=d#a4 ,x w\ld appe> t ! fact t ! /rata1 consid]$ z def9itely ext5d$ masses1 7 arrang$ "o ^u ano!r 9 a c]ta9 settl$ ord] or s]ies 0 fir/ publi%$ by ,john ,/ra*ey 9 ! ,philosophical ,transactions = #agai & #agbe4 ,9 a section he repres5ts1 9 _! true ord]1 *alk1 oolites1 lias1 r$ m>ls & coal1 & ! metallif]\s rocks ( ,som]set%ire1 b conf9es 8 att5tion to ! rocks ( a limit$ di/rict4 ,footnote #a3 ,memoirs ( ,william ,smi?1 ,,ll4,d4 ,by ,j4 ,phillips1 ,f4,r4,s41 ,f4,g4,s4 #ahdd4 ,! ,rev4 ,john ,mi*ell publi%$ 9 ! ,philosophical ,transactions = #agfj an ,essay on ! ,cause & ,phnom5a ( ,e>?quakes1 b ,pr(4 ,phillips gives pro(s t ,mi*ell1 :o 9 #agfb became ,woodw>dian ,pr(essor1 _h be=e #aghh discov]$ 7:at he nev] publi%$7 ! fir/ approximate succession ( ! ,mesozoic rocks1 9 ! di/rict ext5d+ f ,york%ire to ! c\ntry ab\t ,cambridge4 ,mi*ell's acc\nt 0 discov]$ writt5 by ,smeaton on ! back ( a lett] dat$ #aghh4 ,! foll[+ is ! succession z quot$ 9 ,phillips' memoir 7p4 #acf73 ,y>ds ( ?ickness4 ,*alk #abj ,golt #ej ,s& ( ,b$=d%ire #aj to #bj ,nor?ampton%ire lime & ,portl& lime1 ly+ 9 sev]al /rata #ajj ,lyas /rata #gh to #ajj ,s& ( ,new>k ab\t #cj ,r$ ,clay ( ,tux=d1 & sev]al #ajj ,%]wood ,=e/ pebbles & gravel #ej unequal ,v f9e :ite s& unc]ta9 ,ro*e ,abbey & ,bro!rton limes #ajj ,coal /rata ( ,york%ire -- ,! ord] ( succession ( ! ,cretace\s1 ,jurassic1 ,triassic & ,p]mian b$s w be readily recognis$ z indicat$ 9 ?is section1 ?\gh ! discov]y ( ! detail$ succession ( ! ,jurassic rocks 0 res]v$ = ,smi?4 ,9 ! ye> #aggh1 ,john ,:itehur/ publi%$ ,an ,inquiry into ! ,orig9al ,/ate & ,=mation ( ! ,e>?1 conta9+ an ,app5dix 9 :i* ! g5]al succession ( ! /rata ( ,d]by%ire is not$4 ,! ma9 po9ts ( int]e/ are t ! au?or cle>ly recognis$ ! 'toad-/ones' ( ,d]by%ire z igne\s rocks1 z mu* a lava z t :i* fl[s f ,hecla1 ,vesuvius1 or tna1 ?\gh he believ$ t !y 7 intrusive & n contemporane\s1 & he also =e%ad[s ! di/9ction betwe5 ! solid /rata & ! sup]ficial deposits1--we may conclude1 he says1 t all b$s ( s& & gravel are assemblages ( adv5titi\s bodies & n orig9al /rata3 !re=e :]ev] s& or gravel =m ! surface ( ! e>?1 !y conceal ! orig9al /rata f our obs]vation1 & deprive u ( ! advantages ( judg+1 :e!r coal or lime/one are conta9$ 9 ! l[] regions ( ! e>?1 & m especially 9 flat c\ntries :]e ! /rata d n basset4 ,w]n]1 :o 0 born 9 #agej1 ex]cis$ m influ5ce by 8 tea*+ ?an by 8 writ+s4 ,8 ideas ( /ratigraphical geology 7 some:at vitiat$ by 8 !oretical views conc]n+ ! deposition ( s$im5t f a univ]sal ocean1 9 a def9ite ord]1 beg9n+ ) granite1 foll[$ by gneiss1 s*i/s1 s]p5t9es1 porphyries & traps1 & la/ly ord9>y s$im5ts4 ,he recognis$ & taught t ^! rocks _h a def9ite ord] 9 :i* ! rema9s ( liv+ bodies are successively accumulat$1 9 an ord] n less det]m9ate ?an t ( ! rocks :i* conta9 !m#b4 ,! limit$ value ( ,w]n]'s /ratigraphical tea*+ is acc\nt$ = by ,lyell1 :o rem>ks t ,w]n] _h n travell$ to di/ant c\ntries2 he _h m]ely explor$ a small portion ( ,g]many1 & conceiv$ & p]suad$ o!rs to believe t ! :ole surface ( our planet1 & all ! m\nta9-*a9s 9 ! _w1 7 made aft] ! model ( 8 own prov9ce1 & ! au?or ( ! ,pr9ciples ju/ly calls att5tion to ! great importance ( travel to ! geologi/4 ,^? :o _c travel ext5sively %\ld at any rate pay special att5tion to ! works publi%$ ^u di/ricts o!r ?an _! own1 & ev5 at ! pres5t "t1 ! writ+s ( "s ,briti% work]s are apt to be m>k$ by "s ( t 'insul>ity' :i* our neighb\rs reg>d z a national *>act]i/ic4 ,footnote #b3 ,cuvi]'s ,eloge4 ,x is n[ "t to turn directly to ! "w ( ,william ,smi?1 :o1 ( all m51 ex]cis$ ! mo/ pr(\nd influ5ce ^u ! /udy ( /ratigraphical geology & may inde$ be reg>d$ z ! true f\nd] ( t bran* ( ! sci5ce4 ,! memoir ( 8 life :i* 0 be=e m5tion$ is all too %ort to illu/rate ! me?ods ( "w :i* he foll[$1 b 9 x we c trace 8 success to ?ree ?+s3--fir/ly1 8 'eye = a c\ntry1' to use a phrase :i* is ?or\ghly und]/ood by practical geologi/s1 ?\gh x is h>d to expla9 to o!rs1 inasmu* z x epitomises a numb] ( qualifications ( :i* ! mo/ important are1 a ready recognition ( ! ma9 geological features f "s coign ( vantage1 an intuitive p]ception ( :at to note & :at to neglect1 & ! p[] ( /or+ up acquir$ in=mation 9 ! m9d r ?an ! note-book1 s t "o may use x almo/ unconsci\sly = future "w2 secondly1 ability to draw conclusions f 8 obs]vations1 & ?irdly1 & p]haps mo/ important ( all 9 its ultimate results1 a facility = *eck+ ^! conclusions by means ( fur!r obs]vations1 & dropp+ ^? :i* 7 cle>ly errone\s1 :il/ extract+ ! tru? f ^? :i* conta9$ a g]m ( tru? mix$ ) error4 ,besides writ]s ref]r$ to above "s =eign writ]s1 9 p>ticul> ,scilla & ,r\elle1 appe> to h made v j comp>isons ( ! natural associations ( fossil %ells1 corals1 c4 9 ! e>?1 ) ! gr\ps ( simil> objects z !y are f\nd 9 ! sea1 & ?us to h produc$ new pro(s ( ! organic orig9 ( ^! fossil bodies2 b !y give no sign ( any k ( ! limitation ( p>ticul> tribes ( organic rema9s to p>ticul> /rata1 ( ! successive exi/5ce ( diff]5t gr\ps ( organization1 on successive b$s ( ! anti5t sea4 ,mr ,smi?'s claim to ?is happy & f]tile induction is cle> & unque/ionable#c4 ,we get a clue to ! mann] 9 :i* he arriv$ at 8 view 9 ! foll[+ passage#d3--;,accu/om$ to view ! surfaces ( ! sev]al /rata :i* are met ) ne> ,ba? uncov]$ 9 l>ge bread?s at once1 ,mr ,smi? saw ) ! di/9ctness ( c]ta9ty1 t 'ea* /ratum _h be5 9 succession ! b$ ( ! sea'2 f9d+ 9 sev]al ( ^! /rata abundance ( ! exuviae ( m>9e animals1 he conclud$ t ^! animals _h liv$ & di$ dur+ ! p]iod ( "t :i* elaps$ betwe5 ! =mation ( ! /ratum bel[ & ! /ratum above1 at or ne> ! places :]e n[ !y are imb$d$2 & obs]v+ t 9 ! successively-deposit$ /rata ! organic rema9s 7 ( diff]5t =ms & /ructures--,gryphites 9 ! lias1 ,trigoni 9 ! inf]ior oolite1 hook$ oy/]s 9 ! full]'s e>?1--& f9d+ ^! facts repeat$ 9 o!r di/ricts1 he inf]r$ t ea* ( ! sep>ate p]iods occupi$ 9 ! =mation ( ! /rata 0 accompani$ by a peculi> s]ies ( ! =ms ( organic life1 t ^! =ms *>act]iz$ ^? p]iods1 & t ! diff]5t /rata c\ld be id5tifi$ 9 diff]5t localities & o!rwise d\btful cases by peculi> imb$d$ organic rema9s#e4 ,footnote #c3 ,memoir ( ,william ,smi?1 p4 #adb4 ,footnote #d3 ,ibid4 p4 #ada4 ,footnote #e3 ,! "w ( ,smi? :i* directly be>s ^u ! e/abli%m5t ( ! law ( id5tification ( /rata by includ$ organisms is publi%$ 9 two treatises1 entitl$3-- 7i7 ,/rata id5tifi$ by ,organiz$ ,fossils1 #dto4 7int5d$ to comprise sev5 p>ts1 ( :i* f\r only 7 publi%$71 comm5c$ 9 #ahaf4 7ii7 ,a ,/ratigraphical ,sy/em ( ,organiz$ ,fossils1 compil$ f ! orig9al ,geological ,collection deposit$ 9 ! ,briti% ,museum4 #dto4 #ahag4 ,william ,smi? seems to h recognis$ intuitively ! tru? ( a law :i* 0 b dimly und]/ood be=e 8 "t1--! law ( sup]position1 :i* may be ?us /at$3 ( any two /rata1 ! "o :i* 0 orig9ally ! l[]1 is ! old]4 ,?is may appe> self-evid5t b x 0 c]ta9ly n s4 ,z ! result ( ?is recognition he e/abli%$ ! second great /ratigraphical law1 ) :i* 8 "n w ev] be l9k$1 t /rata are id5tifiable by _! includ$ organisms4 ,be=e ,smi?'s "t1 geological maps 7 li?ological r ?an /ratigraphical1 !y repres5t$ ! diff]5t k9ds ( rocks se5 ^u ! surface )\t reg>d to _! age2 s9ce ,smi? revolutionis$ geology1 ! maps ( a c\ntry compos$ l>gely ( /ratifi$ rocks are ess5tially /ratigraphical1 b p>tly no d\bt on acc\nt ( adh]5ce to old cu/om1 p>tly on economic gr\nds1 ! majority ( our /ratigraphical maps are li?ological r ?an palontological1 t is ! subdivisions ( ! /rata repres5t$ ^u ! map are *os5 r on acc\nt ( li?ological peculi>ities ?an because ( ! v>iations 9 _! enclos$ organisms4 ,x is h>dly likely t ,gov]nm5t surveys w be all[$ to publi% palontological maps1 :i* w be almo/ exclusively ( !oretical int]e/1 & x rema9s = zeal\s private individuals to accompli% ! production ( su* maps4 ,:5 !y are produc$1 a comp>ison ( /ratigraphical maps f\nd$ on li?ological & palontological consid]ations w furni% results ( extreme sci5tific int]e/4 ,turn+ n[ f ,smi?'s contributions to ! sci5ce z a :ole1 we may n[ consid] :at he did = ,briti% geology4 ,8 geological map 0 publi%$ 9 #ahae & 0 describ$ z foll[s3--,a ,geological ,map ( ,engl& & ,wales1 ) "p ( ,scotl&2 exhibit+ ! ,colli]ies1 ,m9es1 & ,canals1 ! ,m>%es & ,f5 ,l&s orig9ally ov]fl[$ by ! ,sea1 & ! v>ieties ( ,soil1 accord+ to ! v>iations ( ! ,sub/rata2 illu/rat$ by ! mo/ descriptive ,names ( ,places & ( ,local ,di/ricts2 %[+ also ! ,riv]s1 ,sites ( ,p>ks1 & pr9cipal ,seats ( ! ,nobility & ,g5try1 & ! opposite ,coa/ ( ,france4 ,by ,william ,smi?1 ,m9]al ,surveyor4 ,! map 0 orig9ally on ! scale ( five miles to an in*4 ,9 #ahai a r$uc$ map 0 publi%$1 & 9 lat] ye>s a s]ies ( c\nty maps4 ,he also publi%$ sev]al geological sections1 includ+ "o 79 #ahai7 %[+ ! /rata f ,london to ,sn[don4 ,! /ud5t %\ld comp>e ,smi?'s map ( ! /rata ) "o publi%$ 9 mod]n times 9 ord] to see h[ accurate 0 ,smi?'s del9eation ( ! outcrop ( ! lat] deposits ( our isl&4 ,! foll[+ table1 tak5 f ,phillips' memoir1 p4 #adf1 is also ( int]e/ z %[+ ! developm5t ( ,smi?'s "w & ! complet5ess ( 8 classification 9 8 lat] ye>s1 & z illu/rat+ h[ mu* we are indebt$ to ,smi? = our pres5t nom5clature1 s mu* s t z ,pr(4 ,s$gwick rem>k$ :5 pres5t+ ! fir/ ,wolla/on ,m$al ( ! ,geological ,society to ,smi?1 ,if 9 ! pride ( our pres5t /r5g?1 we 7 dispos$ to =get our orig91 our v spee* w\ld bewray u3 = we use ! language :i* he taught u 9 ! infancy ( our sci5ce4 ,if we1 by our unit$ ef=ts1 are *isell+ ! ornam5ts & sl[ly rais+ up ! p9nacles ( "o ( ! temples ( nature1 x 0 he :o gave ! plan1 & laid ! f\ndations1 & erect$ a portion ( ! solid walls by ! unassi/$ lab\r ( 8 h&s4#f ,footnote #f3 ,! read] may consult an int]e/+ pap] by ,pr(essor ,judd1 on ,william ,smi?'s ,manuscript ,maps1 ,geological ,magaz9e1 ,decade ,,iv4 vol4 ,,iv4 7#ahig7 p4 #dci4 ,comp>ative ,view ( ! ,names & ,succession ( ! ,/rata4 ---------------------------------------- ------------------------------- ,improv$ table drawn up ,table drawn up ,table accompany+ ! 9 #ahae & #ahaf aft] 9 #agii4 map1 drawn up 9 #ahab4 ! fir/ copies ( ! map _h be5 issu$4 ---------------------------------------- ------------------------------- ,london ,clay #a ,london ,clay ,clay or ,brick-e>? #b ,s& #c ,crag ,s& or light loam #d ,s& #a ,*alk ,*alk #e ,*alk ,upp] ,l[] #b ,s& ,gre5 ,s& #f ,gre5 ,s& ,blue ,m>l #g ,brick ,e>? ,purbeck ,/one1 ,k5ti% #h ,s& ,rag & ,lime/one #i ,portl& ,rock ( ! vales #aj ,s& ( ,pick]+ & #aa ,oaktree ,clay ,aylesbury1 #ab ,coral ,rag & ,pisolite ,iron ,s& & ,c>/one #ac ,s& #c ,clay ,d>k ,blue ,%ale #ad ,clun* ,clay & ,%ale #ae ,kell[ay's ,/one ,cornbra% #af ,cornbra% #d ,s& & ,/one #ag ,s& & ,s&/one #e ,clay #f ,=e/ ,m>ble ,=e/ ,m>ble ,rock #ah ,=e/ ,m>ble #ai ,clay ov] ,upp] ,oolite #g ,free/one ,great ,oolite ,rock #bj ,upp] ,oolite #h ,blue ,clay #i ,yell[ ,clay #aj ,full]'s ,e>? #ba ,full]'s ,e>? & ,rock #aa ,ba/>d ditto & ,sundries #ab ,free/one ,"u ,oolite #bb ,"u ,oolite #ac ,s& #bc ,s& #bd ,m>l/one #ad ,m>l ,blue ,blue ,m>l #be ,blue ,m>l #ae ,blue ,lias ,blue ,lias #bf ,blue ,lias #af ,:ite ,lias ,:ite ,lias #bg ,:ite ,lias #ag ,m>l/one1 ,indigo & ,black ,m>ls #ah ,r$ ,gr\nd ,r$ ,m>l & ,gypsum #bh ,r$ ,m>l #ai ,mill/one ,magnesian ,lime/one #bi ,r$l& ,lime/one ,s(t ,s&/one #bj ,p5nant ,/reet #ba ,grays ,coal ,di/ricts #cj ,coal ,measures #bb ,cliff #bc ,coal ,d]by%ire ,lime/one #ca ,m\nta9 ,lime/one ,r$ & ,dun/one #cb ,r$ ,rhab & ,dun/one ,killas or ,slate #cc ,killas ,granite1 ,si5ite & #cd ,granite1 ,si5ite & ,gneiss ,gneiss ---------------------------------------- ------------------------------- ,! above table conta9s a v complete classification ( ! ,briti% ,mesozoic rocks1 "o ( ! ,t]ti>y /rata :i* is less complete1 & a prelim9>y division ( ! ,palozoic rocks into ,p]mian 7,r$l& ,lime/one71 ,c>bonif]\s 7,coal ,measures & ,m\nta9 ,lime/one71 ,devonian 7,r$ ,rhab & ,dun/one7 & ,l[] ,palozoic 7,killas74 ,s9ce ,smi?'s "t ! ma9 "w :i* has be5 done 9 classification is a full] elucidation ( ! sequ5ce ( ! ,t]ti>y & ,palozoic ,rocks1 & ?is we may n[ consid]4 ,! ,mesozoic rocks are develop$ 9 ,brita9 "u circum/ances :i* r5d] ! application ( ! te/ ( sup]position comp>atively simple1 = ! v>i\s subdivisions crop out on ! surface ov] long di/ances1 & ! /ratification is n greatly di/urb$4 ,) ! ,t]ti>y & ,palozoic ,rocks x is o!rwise1 = "s memb]s ( ! =m] are f\nd 9 isolat$ pat*es1 :il/ ! latt] h usually be5 mu* di/urb$ aft] _! =mation4 ,comm5c+ ) ! ,t]ti>y deposits we may note t ! fir/ deposits ( ?is class1 ( :i* ! *>act]s 7 accurately det]m9$1 7 ^? occurr+ 9 ! neighb\rhood ( ,p>is1 describ$ 9 #ahaj by ,,mm4 ,cuvi] & ,brongni>t4444 ,/rata 7 soon aft]w>ds br\ght to light 9 ! vic9ity ( ,london1 & 9 ,hamp%ire1 :i* al?\gh dissimil> 9 m9]al composition 7 ju/ly inf]r$ by ,mr ,t4 ,web/] to be ( ! same age z ^? ( ,p>is1 because ! great] numb] ( fossil %ells 7 specifically id5tical#g4 ,x is to ,lyell t we owe ! e/abli%m5t ( a satisfactory classification ( ! ,t]ti>y deposits :i* is ! basis ( lat] classifications4 ,recognis+ ! difficulty ( apply+ ! ord9>y te/ ( sup]position to deposits s scatt]$ z are ^? ( ,t]ti>y age 9 nor?-we/ ,europe1 he 9 #ahcj1 assi/$ by ,g4 ,p4 ,de%ayes1 propos$ a classification bas$ on ! p]c5tage ( rec5t mollusca 9 ! v>i\s deposits4 ,x may be not$1 t al?\gh ?is me?od 0 suffici5t = ! purpose1 x has be5 practically sup]s$$1 z ! result ( increase ( our k ( ! ,t]ti>y faunas1 by ! m g5]al me?od ( id5tify+ ! v>i\s divisions by _! actual fossils )\t ref]5ce to ! numb] ( liv+ =ms conta9$ among/ !m4 ,! fur!r /udy ( ! ,briti% ,t]ti>y rocks 0 l>gely c>ri$ on by ,joseph ,pre/wi*1 =m]ly ,pr(essor ( ,geology 9 ! ,univ]sity ( ,ox=d4 ,footnote #g3 ,lyell1 ,/ud5ts' ,elem5ts ( ,geology4 #bnd ,edition1 p4 #aah4 ,among/ ! ,palozoic rocks1 x has be5 se5 t ! ,p]mian1 ,c>bonif]\s & "s ( ! ,devonian b$s 7 recognis$ z di/9ct by ,smi?1 ?\gh a l>ge numb] ( deposits n[ kn[n to belong to ! la/ nam$ 7 ?r[n 9 ) o!r rocks z 'killas4' ,! ,devonian sy/em 0 e/abli%$ & ! "n giv5 to x 9 #ahch by ,s$gwick & ,mur*ison1 l>gely ow+ to ! palontological rese>*es ( ,lonsdale4 ,an attempt 0 subsequ5tly made to aboli% ! sy/em1 b ! detail$ palontological /udies ( ,r4 ,e!ridge f9ally plac$ x ^u a secure basis4 ,! e/abli%m5t ( ! ,devonian sy/em cle>$ ! way = ! "r und]/&+ ( ! ,l[] ,palozoic rocks1 :i* ,s$gwick & ,mur*ison _h comm5c$ to /udy be=e ! actual e/abli%m5t ( ! ,devonian sy/em1 & to ^! work]s belongs ! cr$it ( practically complet+ :at 0 begun by ,william ,smi?1 namely1 ! e/abli%m5t ( ! ,geological ,sequ5ce ( ! ,briti% /rata4 ,! controv]sy :i* un=tunately m>k$ ! e>ly ye>s ( ! /udy ( ! ,briti% ,l[] ,palozoic ,rocks is well-nigh =gott51 & 9 ! future ! names ( ,s$gwick & ,mur*ison w be h&$ d[n toge!r1 9 ! mann] :i* is mo/ fitt+4 ,our acc\nt ( ! gr[? ( ,briti% ,/ratigraphical ,geology is n yet complete4 ,9 #ahed1 ,sir ,william ,logan appli$ ! t]m ,laur5tian to a gr\p ( rocks discov]$ 9 ,canada1 :i* occurr$ b5ea? ! ,l[] ,palozoic ,rocks4 ,mur*ison %ortly aft]w>ds claim$ c]ta9 rocks 9 ,n4,w4 ,scotl& z be+ ( g5]ally simil> age1 & s9ce !n a numb] ( geologi/s1 mo/ ( :om are /ill liv+1 h prov$ ! occurr5ce ( sev]al l>ge subdivisions ( rocks 9 ,brita91 ea* ( :i* is ( pre-,palozoic age4 ,! above is a brief description ( ! gr[? ( our k ( ! ord] ( succession ( ! /rata :i* is ! f\ndation ( ,/ratigraphical ,geology4 ,a sket* ( ! mann] 9 :i* ! k :i* has be5 obta9$ has be5 appli$ to ! elucidation ( ! e>?'s hi/ory ( diff]5t times w\ld require f> m space ?an c be devot$ to x 9 a "w l ! pres5t1 b "s idea ( x may be ga9$ f a /udy ( ! lat] *apt]s ( ! book4 ,x w suffice "h to rem>k1 t to ,godw9-,au/5 we owe ! f\ndation ( :at may be t]m$ ! physical bran* ( ,palo-physiography1 :i* is conc]n$ ) ! re/oration ( ! physical conditions ( pa/ ages1 :ile ,cuvi] & ,d>w9 h ex]t$ ! mo/ influ5ce on ! /udy ( ,/ratigraphical ,palontology4 ,,*apt] ,,iii4 ,,nature ,,( ,,! ,,/ratifi$ ,,rocks4 ,! pres5t con/itu5ts ( ! e>? :i* are accessible = direct /udy are divisible into ?ree p>ts4 ,! inn] portion1 consi/+ ( rocks1 is kn[n z ! li?osph]e2 outside ?is1 ) portions ( ! li?osph]e project+ ?r\gh into ! out]mo/ "p1 is ! hydrosph]e1 compris+ ! ocean1 lakes1 riv]s1 & all masses ( wat] :i* re/ ^u ! li?osph]e 9 a liquid condition4 ,! out]mo/ envelope1 :i* is cont9u\s & unbrok5 is ! atmosph]e1 9 a gase\s condition4 ,x is well kn[n t "s ( ! con/itu5ts ( any "o ( ^! p>ts may be ab/ract$ f x1 & become a compon5t ( ei!r ( ! o!rs2 ?us ! atmosph]e ab/racts aque\s vap\r f ! hydrosph]e1 & ! li?osph]e takes up wat] f ! hydrosph]e1 & c>bonic anhydride f ! atmosph]e4 ,! nebul> hypo!sis ( ,kant & ,laplace necessitates ! =m] exi/5ce ( ! pres5t solid portions ( ! li?osph]e 9 a molt5 condition1 & accord+ly ! fir/ =m$ solid cov]+ ( ! li?osph]e1 if ?is hypo!sis be true1 mu/ h be5 =m$ f molt5 mat]ial1 or 9 ! language ( ,geology1 x 0 an igne\s rock4 ,consequ5tly1 ! e>lie/ s$im5t>y rock 0 necess>ily d]iv$ directly f an igne\s rock1 ) possible addition ( mat]ial f ! e>ly hydrosph]e & atmosph]e1 & all subsequ5tly =m$ s$im5t>y rocks h !re=e be5 d]iv$ f igne\s rocks 7) ! additions above /at$7 ei!r directly1 or indirectly ?r\gh ! break+ up ( o!r s$im5t>y rocks :i* 7 !mselves d]iv$ directly or indirectly f igne\s rocks4 ,! obs]vations ( geologi/s %[ t ?is supposition t ! mat]ials ( s$im5ts h be5 directly or indirectly obta9$ = ! mo/ "p f once-molt5 rocks is 9 accordance ) ! obs]v$ facts1 & s f> _! obs]vations te/ify to ! tru? ( ! nebul> hypo!sis4 ,?is be+ ! case1 ! /udy ( ! petrology ( ! igne\s rocks is necess>y1 9 ord] to arrive at a true und]/&+ ( ! composition ( ! s$im5t>y ones4 ,! igne\s rocks are l>gely compos$ ( f\r gr\ps ( m9]als1 viz4--qu>tz1 felsp>s1 f]ro-magnesian m9]als1 & ores4 ,( ^! ! qu>tz 7compos$ ( silica7 yields p>ticles ( silica = ! =mation ( s$im5t>y rocks2 ! felsp>s1 :i* are d\ble silicates ( alum9a & an alkali or alkal9e e>?1 be+ prone to decomposition furni% silicate ( alum9a & comp\nds ( soda1 pota%1 lime1 c4 ,! f]ro-magnesian m9]als 7su* z augite1 hornbl5de & mica7 may und]go a c]ta9 am\nt ( decomposition1 & yield comp\nds ( iron1 lime1 c4 ,we may also h fragm5ts ( any ( ^! m9]als1 & ( ! ore gr\p 9 an unalt]$ condition4 ,! composition ( a s$im5t>y rock :i* has und]gone no alt]ation aft] its =mation w !re=e dep5d ^u ! "* ( ! rock f :i* x 0 d]iv$1 ! *emical *anges :i* take place 9 ! mat]ials :i* compose x1 be=e !y ent] into its mass1 & ! me*anical sort+ :i* !y und]go prior to _! deposition4 ,9 ! above passage ! t]ms igne\s rock & s$im5t>y rock h be5 us$1 & x is necess>y to give "s acc\nt ( ! s5se 9 :i* !y 7 us$4 ,an igne\s rock is "o :i* has be5 consolidat$ f a /ate ( fusion4 ,x is n necess>y to discuss "h ! exact significance ( ! ^w fusion1 & :e!r c]ta9 rocks :i* are includ$ 9 ! igne\s division 7 =m$ r f solution at high temp]ature ?an f actual fusion4 ,?is po9t is ( importance to ! petrologi/1 b to ! /ud5t ( /ratigraphical geology ! t]m igne\s rock may be us$ 9 its mo/ compreh5sive s5se4 ,^! igne\s rocks 7 consolidat$ ei!r ^u ! surface ( ! li?osph]e or 9 its int]ior4 ,! o!r great gr\p ( rocks is "o to :i* x is difficult to apply a satisfactory "n4 ,!y h be5 t]m$ by diff]5t writ]s1 s$im5t>y1 /ratifi$1 d]ivative1 aque\s1 & cla/ic1 b no "o ( ^! t]ms is /rictly accurate4 ,! t]m s$im5t>y implies t !y h settl$ d[n1 at ! bottom ( a %eet ( wat] = in/ance4 ,x c h>dly be ma9ta9$ t lime/ones =m$ by organic ag5cy1 l ! lime/ones ( coral reefs1 are s$im5t>y 9 ! /rict s5se ( ! t]m1 & an accumulation l surface-soil c only be call$ a s$im5t by /ra9+ ! t]m4 ,/ratifi$ rocks are ^? :i* are =m$ 9 /rata or lay]s1 b _m ( ! rocks :i* we are consid]+ d n %[ lay]s on a small scale1 & igne\s rocks 7su* z lava-fl[s7 are also f\nd 9 lay]s1 ?\gh su* lay]s are n true /rata 9 ! s5se 9 :i* ! t]m is us$ by geologi/s2 ! t]m /ratifi$ is p]haps ! lea/ op5 to objection ( any ( ^? nam$ above4 ,d]ivative implies t ! fragm5ts h be5 d]iv$ f "s pre-exi/+ rock1 b z !re are _m ways 9 :i* fragm5ts ( "o rock may be d]iv$ f ano!r1 ! t]m is too compreh5sive4 ,aque\s rocks %\ld be =m$ 9 wat]1 & mo/ ( ! class ( rocks :i* we are consid]+ h be5 s =m$1 b o!rs su* z s&-dunes & surface-soil h n4 7,! t]m ,a]ial or olian has be5 sugge/$ to include ^! rocks :i* are ?us sep>at$ f ! ,aque\s rocks prop]2 ! objection to ?is is t ! orig9 ( ^! rocks is closely connect$ ) t ( ! true ,aque\s rocks1 & moreov] ! gr\p is too small to be rais$ to ! dignity ( a sep>ate subdivision47 ,la/ly1 ! "n cla/ic has be5 giv51 because ! rocks s call$ are =m$ by ! break+ up ( pre-exi/+ rocks4 ,!re are two objections to ?is "n4 ,9 ! fir/ place1 "s rocks includ$ "u ! head cla/ic are =m$ by solution ( mat]ial & its consolidation f a /ate ( solution by *emical or organic ag5cy1 ?\gh we may p]haps speak ( rocks be+ brok5 up by *emical z well z by me*anical action4 ,! mo/ important objection is t _m cla/ic rocks are =m$ by ! break+ up ( rocks subsequ5tly to _! =mation1 & x has be5 propos$ t rocks ( ?is nature %\ld be t]m$ catacla/ic1 :ile ^? :i* are =m$ by ! break+ up ( pre-exi/+ rocks ^u ! e>?'s surface %\ld be t]m$ epicla/ic2 ano!r gr\p =m$ ( mat]ials brok5 up )9 ! e>?1 & accumulat$ ^u its surface z ! result ( ejection ( fragm5tal mat]ial f volcanic v5ts be+ t]m$ pyrocla/ic4 ,?is classification is sci5tific1 & "u special circum/ances is extremely useful1 b ! old] t]ms h be5 us$ s g5]ally1 & ) ?is explanation _! use is s unobjectionable1 t !y may be reta9$1 & ! t]m /ratifi$ w be g5]ally us$ to indicate all rocks :i* are n ( igne\s orig9 or =m$ z m9]al ve9s 9 ! e>?'s int]ior4 ,! division ( rocks into ?ree great gr\ps1 ! ,igne\s1 ,/ratifi$ & ,metamorphic 7! latt] "n be+ appli$ to ^? rocks :i* h und]gone consid]able alt]ation s9ce _! =mation71 is objectionable1 s9ce we h metamorphic igne\s rocks z well z metamorphic /ratifi$ ones4 ,! mo/ conv5i5t classification is z foll[s3-- ,a4 ,igne\s #a4 ,unalt]$4 #b4 ,metamorphic4 ,b4 ,/ratifi$ #a4 ,unalt]$4 #b4 ,metamorphic4 ,x mu/ be di/9ctly und]/ood t all geological ph5om5a mu/ be tak5 into acc\nt by ! /ratigraphical geologi/4 ,! upheaval ( /rata1 ! production ( jo9t+ & cleavage 9 !m1 _! intrusion by igne\s mat]ial1 _! metamorphism1 give indications ( =m] physical conditions equally ) ! li?ological *>act]s ( ! /rata1 & _! fossil cont5ts4 ,nev]!less x is n propos$ to give a full acc\nt ( ! v>i\s ph5om5a display$ by rocks2 ! /ud5t is ref]r$ to ,text-books ( ,g5]al ,geology = ?is in=mation4 ,x w be z well "h1 h[ev]1 to po9t out 9 a few words ! exact significance ( ! exi/5ce ( /rata 9 ! li?osph]e4 ,! =mation ( /rata & _! subsequ5t de/ruction to supply mat]ial = fre% /rata are due to ?ree great classes ( *anges4 ,beg9n+ ) a portion ( li?osph]e compos$ ( rock1 x is f\nd t rock is brok5 up by ag5ts ( d5udation1 z w9d1 ra91 fro/1 riv]s & sea4 ,^! ag5ts p]=m _! function ma9ly ^u ! portion ( ! li?osph]e :i* projects ?r\gh ! hydrosph]e to =m l&1 & ! l& is ! ma9 area ( d5udation4 ,! mat]ials furni%$ by d5udation are c>ri$ away1 & ow+ to gravitation1 naturally proce$ f a high] to a l[] level1 (t5 re/+ on ! way1 b if no?+ else occurs1 ultimately f9d+ _! way to ! sea1 :]e !y are deposit$ z /rata4 ,! sea is ! pr9cipal area = ! reception ( ?is mat]ial1 & x is !re accord+ly t ! bulk ( /ratifi$ rock is =m$4 ,if no?+ else occurr$1 9 "t ! :ole ( ! l& w\ld be de/roy$1 & ! wreckage ( ! l& deposit$ b5ea? ! sea z /ratifi$ rock4 ,z x is !re is a ?ird class ( *ange1 und]gr\nd *ange1 caus+ movem5ts ( ! e>?'s cru/ 7to use a t]m :i* c h>dly be def9$ 9 few words b :i* is g5]ally und]/ood71 & z ! result ( ! relative uplift ( portions ( ! e>?'s cru/1 ! /ratifi$ rocks =m$ b5ea? ! oceans are rais$ above its level1 giv+ rise to new masses ( l&1 :i* are once m ready = de/ruction by ! ag5ts ( d5udation4 ,?is cycle ( *ange 7all p>ts ( :i* are ev] proce$+ simultane\sly7 is "o ( ! utmo/ importance to ! /ratigraphical geologi/4 ,/ratification is ! rock-/ructure ( prime importance 9 /ratigraphical geology1 & a few words mu/ "h be devot$ to its consid]ation1 leav+ fur!r details to be dealt ) h]eaft]4 ,! surface ( ! ocean-floor is1 :5 view$ on a l>ge scale1 s level1 t x may be consid]$ practically horizontal1 & accord+ly 9 mo/ places ! mat]ials :i* are laid d[n on ! ocean-floor give rise to accumulations :i* at all times h a g5]al horizontal surface 7:5 ! ocean-slopes dep>t m>k$ly f horizontality ! deposits t5d to abut aga9/ ^! slopes r ?an to lie ) _! upp] surfaces p>allel to _! orig9al angle74 ,a practically horizontal surface ( ?is "* may give rise to a plane ( /ratification 7or b$d+-plane7 9 m ?an "o way4 ,a pause may occur dur+ :i* !re is a cessation ( ! supply ( mat]ial1 s t ! mat]ial :i* has already be5 accumulat$ has suffici5t "t to become p>tially consolidat$ be=e ! deposition ( fre% mat]ial ^u x4 ,9 ?is way a want ( coh]5ce betwe5 ! two masses is produc$1 along ! plane ( junction1 :i* aft] consolidation ( ! deposits causes an actual divisional plane along :i* ! two deposits may be sep>at$4 ,?is is a plane ( /ratification4 ,! pause may be produc$ 9 v>i\s ways1 sometimes betwe5 successive high tides1 at o!rs z ! result ( physical *anges :i* may h tak5 ages to happ54 ,aga91 aft] mat]ial ( "o k9d has be5 deposit$1 say s&1 "s o!r sub/ance su* z clay may be accumulat$ on its upp] surface1 giv+ rise to a plane ( /ratification betwe5 two deposits ( diff]5t li?ological *>act]s4 ,if ?is occurs alone1 !re may be actual coh]5ce betwe5 ! two /rata1 s t x is errone\s to speak ( a plane ( /ratification z if x 7 always "o along :i* "o deposit c\ld be readily split f ! o!r1 ?\gh z a g5]al ?\gh by no means univ]sal rule1 *ange f "o k9d ( deposit to ano!r is also m>k$ by want ( coh]5ce betwe5 ! two4 ,! mat]ial betwe5 two planes ( /ratification =ms a /ratum or b$1 ?\gh if ! deposit be v ?9 x is kn[n z a lam9a1 & ! planes are spok5 ( z planes ( lam9ation 7no h>d & fa/ l9e c be drawn betwe5 /rata & lam92 sev]al ( ! latt] usually occur 9 ! space ( an in*74 ,a /ratum w h its upp] & l[] surface app>5tly p>allel1 ?\gh n really s1 = no /ratum ext5ds univ]sally r\nd ! e>?1 & _m ( !m disappe> at no great di/ance :5 trac$ 9 any direction4 ,p>ts ( "o /ratum may be compos$ ( diff]5t mat]ials f o!r p>ts :5 trac$ lat]ally1 ?us "o /ratum may be f\nd compos$ ess5tially ( s& 9 "o place1 ( mud 9 ano!r1 & ( a mixture ( ! two 9 an int]v5+ locality4 ,:atev] be ! composition ( a /ratum x dies out ev5tually1 ow+ to ! com+ toge!r ( ! upp] & l[] b\nd+ planes ( /ratification4 ,! /ratum is ?icke/ at "s spot1 f t spot x becomes ?9n] 9 all directions1 until x disappe>s at la/ by ! coalesc5ce ( ! b\nd+-planes4 ,?is is spok5 ( z ?9n+-out4 ,/rata1 !n1 consi/ ( l5ticul> masses ( rock1 sep>at$ f ! und]ly+ & ov]ly+ /rata by planes ( /ratification4 ,! %ape ( ! l5ticle may v>y imm5sely1 ! ?ickness be>+ no def9ite relation%ip to ! horizontal ext5t4 ,"s /rata1 _m feet 9 ?ickness1 may ?9 out & disappe> completely 9 ! c\rse ( a few y>ds1 :il/ o!rs an in* or two 9 ?ickness may be trac$ horizontally = _m miles4 ,we (t5 f9d ?9 /rata ( coal & lime/one1 ext5d+ = great di/ances1 /rata ( mud ?9n+ out m rapidly1 & s&/ones /ill m rapidly1 b no univ]sal rule connect+ rapidity ( ?9n+-out ) composition ( ! /rata c be laid d[n4 ,hav+ se5 :at a /ratum is1 x n[ rema9s to speak ( ! composition ( ! /ratifi$ rocks4 ,!y h be5 classifi$ accord+ to _! composition1 & accord+ to _! orig94 ,accord+ to composition !y h be5 divid$ into3 ,ar5ace\s rocks1 compos$ ess5tially ( gra9s ( s&4 ,argillace\s rocks1 compos$ ess5tially ( p>ticles ( mud4 ,calc>e\s rocks1 compos$ ess5tially ( p>ticles ( c>bonate ( lime4 ,c>bonace\s rocks1 compos$ l>gely ( hydroc>bon comp\nds4 ,silice\s rocks1 compos$ ess5tially ( silica n 9 ! =m ( gra9s2 :il/ accord+ to _! orig9 !y h be5 sep>at$ into3-- ,me*anically-=m$ rocks1 compos$ ( fragm5ts d]iv$ f o!r rocks by me*anical fracture4 ,*emically-=m$ rocks1 compos$ ( p>ticles :i* h be5 *emically deposit$ f a /ate ( solution4 ,organically-=m$ rocks1 compos$ ( mat]ials :i* h be5 d]iv$ f a /ate ( solution or f ! gase\s condition by ! ag5cy ( organisms4 ,:i*ev] classification be adopt$ 7& ea* is useful = special purposes71 x mu/ be not$ t no h>d & fa/ l9e c be drawn betwe5 "o division & ano!r4 ,a rock may be p>tly ar5ace\s & p>tly calc>e\s1 compos$ ( a mixture ( s& & lime1 & ! same rock may simil>ly be p>tly me*anically & p>tly organically =m$1 ! s& be+ due to me*anical fracture1 & ! lime to ! ag5cy ( organisms1 & s ) ! o!r divisions4 ,z _m ( ! *anges :i* h occurr$ 9 pa/ times h be5 conc]n$ 9 de/ruction & oblit]ation1 :il/ deposition is ! cause ( pres]vation1 ! /udy ( deposits is peculi>ly adapt$ = te/+ ! tru? ( ! gr& pr9ciple ( geology t ! *anges :i* h tak5 place 9 pa/ times are g5]ally speak+ simil> 9 k9d & 9 int5sity ( action to ^? :i* are 9 progress at ! pres5t day1 & a /udy ( ! mod]n deposits is specially important z ?r[+ light ^u ! *>act]s ( ^? :i* h be5 =m$ 9 pa/ times4 ,x w be abundantly %[n 9 ! sequel t ! deposits ( ! /rata are 9 g5]al comp>able 9 all ess5tial respects ) ^? :i* are be+ =m$ at pres5t1 & accord+ly !y give mo/ valuable indications z to ! nature ( ! physical & o!r conditions "u :i* !y 7 laid d[n4 ,! des]t s&1 ! precipitate ( ! inl& sea1 ! reef-lime/one & _m ano!r deposit c ?us be detect$ by an exam9ation ( _! li?ological *>act]s1 comb9$ ) consid]ation ( o!r k9ds ( evid5ce4 ,! petrology ( ! s$im5t>y rocks is /ill 9 its infancy1 ?\gh mu* has already be5 done1 b x (f]s a wide field ( inquiry to ! field-geologi/ & work] ) ! microscope#h4 ,footnote #h3 ,! /ud5t w d well to consult ,! ,*all5g] ,report by ,messrs ,murray & ,r5>d 7#ahia71 = in=mation conc]n+ _m mod]n s$im5ts1 & ,h>k]'s ,petrology = ,/ud5ts ,section ,d1 = g5]al in=mation on ! ,petrology ( ! ,/ratifi$ ,rocks4 ,,*apt] ,,iv4 ,,! ,,law ,,( ,,sup]position4 ,9 a previ\s *apt] ?is law 0 giv5 z foll[s3 ,( any two /rata1 ! "o :i* 0 orig9ally ! l[] is ! old]2 ! g5]al tru? ( ! law dep5ds ^u ! fact t except "u v exceptional circum/ances ! /rata are deposit$ ^u ! surface ( ! li?osph]e1 & n b5ea? x4 ,!re are occasions :]e /rata may be deposit$ b5ea? ! li?osph]e1 b z a g5]al rule ! geologi/ w n be misl$ by su* occurr5ces4 ,9 cav]ns1 accumulations (t5 occur :i* are new] ?an ! /rata ov] ! cav]n ro(1 & s long z cav]ns are =m$ 9 ord9>y s$im5t>y rocks1 no great difficulty w result f ?is exception to ! law ( sup]position4 ,:5 cav]ns occur b5ea? masses ( l& ice1 ! ord] ( sup]position may be mislead+4 ,a deposit may be =m$ on ! surface ( ! ice1 & subsequ5tly to ?is a new] deposit may be laid d[n 9 a sub-glacial or englacial cav]n2 ^u ! melt+ ( ! ice ! new] deposit w\ld be f\nd ) ! old] "o re/+ ^u its surface4 ,ap>t f ^! exceptional cases1 ! law z /at$ holds good1 b ! read] w notice ! ins]tion ( ! ^w 'orig9ally' :i* requires "s comm5t4 ,a geologi/ speaks ( "o b$ ly+ ^u ano!r n only :5 ! b$s are horizontal1 b :5 !y are incl9$ at any angle1 until !y become v]tical1 s t until b$s h be5 turn$ ?r\gh an angle ( #ij by e>?-movem5t ! te/ ( sup]position is applicable1 b :5 !y h be5 turn$ m ?an #ij1 ! /ratum :i* 0 orig9ally l[] re/s ^u t :i* 0 orig9ally above x1 & 9 ! case ( ^! inv]t$ /rata1 ! te/ ( sup]position is no long] applicable4 ,x 0 =m]ly suppos$ t cases ( inv]sion 7 comp>atively r>e & local1 & t ! te/ ( sup]position c\ld !re=e be g5]ally appli$ ) confid5ce1 b x is n[ kn[n t ?\gh ?is is g5]ally true ( su* /rata z h be5 subject$ only to ^? widespread1 fairly uni=m movem5ts :i* are spok5 ( z epeirog5ic or cont95t-=m+1 :]e ! radius ( ea* curve is v long1 inv]sion is a frequ5t accompanim5t ( ! m local orog5ic or m\nta9-=m+ movem5ts1 :]e ! radius ( a curve is %ort4 ,?\gh orog5ic movem5ts are limit$ z comp>$ ) ^? ( epeirog5ic "*1 !y (t5 affect l>ge tracts ( c\ntry1 9 :i* case ! app>5t ord] ( succession ( ! /rata ne$ n be ! true "o1 & examples ( inv]sion may be frequ5t#i4 ,footnote #i3 ,= a discussion ( ! pr9ciples ( m\nta9-build+ see ,heim1 ,a41 ,unt]su*ung5 b] d5 ,me*anismus d] ,gebirgsbildung1 & ,lapwor?1 ,c4 ,! ,secret ( ! ,highl&s1 ,geological ,magaz9e1 ,decade ,,ii4 vol4 x4 pp4 #abj1 #aic1 #ccg4 ,x is n easy to lay d[n any def9ite rules = detect+ inv]t$ /rata1 :]e ! top ( an inv]t$ ar* is swept (f by d5udation or ! bottom ( an inv]t$ tr\gh conceal$ b5ea? ! surface1 beyond /at+ t if an easily recognis$ set ( b$s is obvi\sly repeat$ 9 inv]se ord]1 inv]sion mu/ h occurr$1 ?\gh ev5 !n x may n be cle> :i* side ( ! fold %[s ! b$s 9 orig9al & :i* 9 inv]t$ sequ5ce4 ,sugge/ions are frequ5tly made t ripple-m>ks & worm-tracks may be utilis$ 9 ord] to discov] inv]sion1 = ! well-=m$ ripple-m>ks w appe> convex on ! upp] surface ( a b$ :i* is n inv]t$1 & we may note concave ca/s ( ^! ripple-m>ks on ! "u surface ( ! ov]ly+ b$1 :il/ worm-tracks w appe> concave on ! upp] surface1 & _! ca/s convex on ! l[] surface ( ! succe$+ b$ "u simil> conditions4 ,9 ! case ( inv]sion ! occurr5ces w be ! exact opposite to ^!4 ,un=tunately ripple-m>ks & worm-tracks may1 z w appe> 9 ! sequel1 be simulat$ by /ructures produc$ 9 q a diff]5t way1 & unless ! obs]v] is c]ta9 t he is confront$ ) true ripple-m>ks & worm-tracks he may be s]i\sly misl$4 ,! geologi/ mu/ take into acc\nt all ! evid5ce at 8 disposal1 :5 he is deal+ ) cases ( possible inv]sion1 b (t5times he w aft] due consid]ation ( all ! ph5om5a be left 9 d\bt unless he is able to supplem5t 8 obs]vations on ! succession ( ! /rata by evid5ce d]iv$ f ! includ$ fossils4 ,! te/ ( sup]position is mo/ apt to be mislead+ :5 ! /rata h be5 affect$ by ! faults kn[n z rev]s$ faults or ?ru/-planes4 ,ref]5ce to text-books w %[ t a fold consi/s ( two p>ts1 ! ar* & ! tr\gh1 & t ! two are connect$ by a common-1 middle-1 or p>tition-limb4 ,9 ! case ( an inv]t$ fold1 an ,s-%ap$ or sigmoidal /ructure is ! result 7,fig4 #a ,a74 ,illu/ration3 ,fig4 #a4 ,a4 ,a sigmoidal fold1 %[+ a b$ xx 9 an ov]fold ) ar* 7a71 tr\gh 7t7 & common limb c4 ,b4 ,a simil> b$ xx affect$ by a ?ru/-plane tt :i* replaces ! common limb4 ,"h ! portions ( any b$ 7xx7 :i* occur 9 ! ar* or tr\gh are 9 normal position1 & h n be5 mov$ r\nd ?r\gh an angle ( #ij1 :il/ ! portion :i* occurs 9 ! common limb c has be5 mov$ r\nd ?r\gh an angle great] ?an #ij & is inv]t$1 s t its =m] upp] surface n[ faces d[nw>ds4 ,9 ,fig4 #a ,b ! common limb is replac$ by a rev]s$ fault1 or ?ru/-plane1 & ! inv]t$ portion ( ! b$ se5 9 ! common limb is !re=e abs5t4 ,an obs]v]1 apply+ ! te/ ( sup]position1 might suppose t ! position ( ! b$ x on ! left-h& side ( ! figure 0 a diff]5t b$ f ! portion :i* is se5 on ! "r-h& side1 in/ead ( belong+ to ! same b$1 & 9 ?is way1 if a numb] ( p>allel ?ru/-planes affect$ "o b$ or a set ( b$s1 he might be l$ to inf] ! occurr5ce ( a great ?ickness ( /rata :]e !re 0 9 reality a slight ?ickness1 or ev5 "o b$ only repeat$ aga9 & aga9 by fault+4 ,x is q c]ta9 t exagg]at$ e/imates ( ! ?ickness ( deposits h frequ5tly be5 made ow+ to ! non-recognition ( ! occurr5ce ( repetition z a consequ5ce ( ! exi/5ce ( ?ru/-planes4 ,:]e ?ru/-planes are suspect$1 x is well to look = "s ( ! foll[+ features3 7a7 ,! /rata ( a c\ntry affect$ by ?ru/-planes (t5 crop out z l5ticul> masses1 ?9n+ out rapidly 9 ! direction ( ! /rike#aj4 ,?is is true ( b$s ?r[n into %>p folds :e!r or n inv]t$1 b ! l5ticles w be wid] 9 a direction at "r angles to t ( ! /rike z comp>$ ) _! l5g? :5 inv]sion has n occurr$4 ,x is also true ( b$s :i* 7 orig9ally deposit$ z l5ticles1 su* z _m massive s&/ones1 & z almo/ any k9d ( deposit may be =m$ orig9ally z a l5ticle1 ! te/ by itself is by no means suffici5t z a pro( ( ?ru/+1 ?\gh x is sugge/ive4 ,footnote #aj3 ,= def9itions ( ! t]ms dip1 /rike1 outcrop & alli$ expressions1 ! read] is ref]r$ to a ,text-,book ( ,geology4 7b7 ,! surfaces ( ! /rata are (t5 affect$ by ! /riations kn[n z slick5sides1 & ! jo9t-faces ( g5tly incl9$ b$s are also frequ5tly m>k$ by slick5sides :i* (t5 run 9 a ne>ly horizontal direction4 7c7 ,a p>allel /ructure pres5t+ ! appe>ances *>act]i/ic ( ! me*anically-=m$ features ( a foliat$ rock is (t5 develop$1 & "o or m ( c]ta9 accompany+ ph5om5a w probably be f\nd1 :i* w be notic$ m fully 9 a lat] *apt]4 7d7 ,ext5sion or /ret*+ ( ! rocks w h be5 frequ5tly produc$1 caus+ rupture1 & ! result+ fissures are usually fill$ ) m9]al-ve9s1 ?\gh ?is occurr5ce is by no means *>act]i/ic ( rocks :i* h be5 affect$ by ?ru/-planes4 7e7 ,*emical *anges may h occurr$ :i* h result$ 9 ! recon/itution ( "s ( ! rock-con/itu5ts1 :i* may cry/allise :]e pressure is lea/1 ?us we (t5 f9d rocks :i* h und]gone movem5ts ( ! type we are consid]+ m>k$ by ! exi/5ce ( s]icitic films ^u ! surfaces4 ,ano!r res]vation mu/ be made :5 consid]+ ! law ( sup]position4 ,! te/ is only applicable = limit$ areas4 ,suppose we f9d a deposit ( clay a re/+ ^u ano!r deposit ( lime/one b 9 ! s\? ( ,engl&1 & c prove t ! app>5t succession is ! true "o1 t is1 t !re has be5 no inv]sion2 x is cle> t ! te/ ( sup]position is applicable 9 t area4 ,n[1 we may be able to trace ! two deposits cont9u\sly across ! c\ntry1 "o z a clay1 ! o!r z a lime/one2 s t :5 we rea* ! nor? ( ,engl& we f9d ! clay a /ill repos+ ^u ! lime/one b4 ,! te/ ( sup]position is applicable 9 t area also1 ! clay ( ! nor!rn area be+ new] ?an ! lime/one ( ! same region4 ,b1 = reasons :i* w ultimately appe>1 x by no means foll[s t ! clay ( ! nor? is new] ?an ! lime/one ( ! s\?1 al?\gh ! two deposits are cont9u\sly traceable ) ! same li?ological *>act]s2 x may h be5 =m$ simultane\sly ) ! lime/one ( ! s\?1 or ev5 be=e x4 ,some?+ m1 !re=e1 ?an ! te/ ( sup]position is necess>y 9 ord] to make out ! relative ages ( cont9u\s deposits 9 a wide region1 & ?is is /ill tru] 9 ! case ( deposits :i* are discont9u\s1 :e!r sep>at$ f "o ano!r by ! sea1 or by outcrops ( old] or new] rocks4 ,a few words ( w>n+ may be add$ ) ref]5ce to ! detection ( b$d+-planes4 ,a b$d+-plane is "o :i* sep>ates two b$s1 & its exi/5ce is det]m9$ dur+ ! deposition ( ! b$s4 ,_m o!r planes are =m$ 9 rocks subsequ5tly to _! deposition1 & x is n always easy to di/+ui% ^! f true b$d+-planes4 ,t ev5 exp]i5c$ obs]v]s may be l$ a/ray is %[n by ! fact t1 ( rec5t ye>s1 x has be5 prov$ t great masses ( rock h be5 claim$ z ( s$im5t>y orig91 & _! app>5t ord] ( succession not$1 :i* are 9 tru? naught b irregul> masses ( intrusive igne\s rocks affect$ by divisional planes :i* simulate b$d+1 produc$ 9 ! rocks subsequ5tly to _! consolidation4 ,jo9ts1 faults1 & cleavage-planes may all at times simulate planes ( b$d+1 & x is frequ5tly v difficult to di/+ui% !m 9 ! limit$ exposures ) :i* a geologi/ has (t5times to deal4 ,x is easi] to make sugge/ions = di/+ui%+ b$d+-planes f o!r planes :i* simulate !m1 ?an to apply ! sugge/ions 9 practice1 & ! /ud5t ( field geology w f9d t exp]i5ce is ! only guide1 ?\gh aft] ye>s ( exp]i5ce he may be confront$ ) cases :]e ! evid5ce is insuffici5t to conv9ce him t he is deal+ ) planes ( /ratification & n ) "s o!r /ructure4 ,f :at has be5 rem>k$1 x w be inf]r$ t ! te/ ( sup]position ?\gh ( prime importance to ! geologi/ is frequ5tly insuffici5t to enable him to asc]ta9 ! true ord] ( succession ( ! /rata1 & he is compell$ to supplem5t ?is te/ by "s o!r4 ,!re are sev]al useful physical te/s :i* may frequ5tly be appli$4 ,?us1 if a rock a conta9s fragm5ts ( ano!r rock b1 "u su* circum/ances z to %[ t ! fragm5ts ( b 7 includ$ 9 a dur+ its deposition1 x is cle> t b is old] ?an a4 ,"h aga91 x w be f\nd f :at appe>s 9 a lat] *apt] t ! /ud5t is confront$ ) difficulties :5 actually exam9+ rocks1 = fragm5tal rocks ( catacla/ic orig91 :]e ! fragm5ts h be5 =m$ z ! result ( fracture produc$ by e>?-movem5ts subsequ5tly to ! deposition ( ! rock1 simulate epicla/ic rocks 9 :i* ! fragm5ts 7 introduc$ dur+ ! accumulation ( ! deposits to s surpris+ a degree z sometimes to baffle ! mo/ exp]i5c$ obs]v]4 ,n only are ! fragm5ts ( ^! catacla/ic rocks brok5 up1 b !y may be fur!r r\nd$ s z to imitate 9 a rem>kable mann] ! wat]-worn pebbles ( an epicla/ic conglom]ate4 ,aga91 an old] s]ies ( rocks may h _h /ructures impress$ ^u !m z ! result ( *anges subsequ5t to _! =mation1 & be=e ! =mation ( a new] set :i* ! latt] !re=e d n exhibit4 ,jo9t+1 cleavage1 & v>i\s metamorphic ph5om5a may ?us be exhibit$ by ! old] rocks1 b great c>e is requir$ 9 apply+ ?is te/1 especially ) a limit$ ?ickness ( rocks1 z "o set may n exhibit ! /ructures n because !y 7 n 9 exi/5ce :5 ! /ructures 7 develop$1 b because _! nature is su* t !y 7 incapable ( receiv+ or reta9+ ! /ructures4 ,= in/ance a mass ( grit :i* is old] ?an a mass ( clay-slate may n be cleav$1 because1 al?\gh subject$ to ! pressure :i* produc$ ! cleavage1 x 0 ( a nature n adapt$ to ! developm5t ( cleavage /ructure4 ,on ! :ole1 application ( te/s dep5d5t ^u physical features ( rocks1 does n (t5 supplem5t to any great ext5t ! in=mation suppli$ by asc]ta9+ ! ord] ( sup]position1 & 9 all cases1 :]e possible1 e o!r k9d ( in=mation %\ld be supplem5t$1 by t :i* is acquir$ aft] exam9ation ( ! includ$ organisms ( ! /rata4 ,,*apt] ,v4 ,,! ,,te/ ,,( ,,includ$ ,,organisms4 ,! second great law ( ! ,/ratigraphical ,geologi/ is t fossilif]\s /rata are id5tifiable by _! includ$ organisms1 9 o!r words1 t we c tell ! geological age ( deposits by exam9ation ( ! fossils conta9$ 9 !m1 ?\gh ! det]m9ation ( age mu/ be giv5 9 m g5]al t]ms 9 "s cases ?an 9 o!rs4 ,consid]able misconception has aris5 conc]n+ ! value ( fossils z indices ( age1 & x is necess>y !re=e to discuss ! significance ( ! law ( id5tification ( /rata by _! includ$ organisms at "s l5g?4 ,! comp>ison betwe5 fossils & m$als has frequ5tly be5 made & fossils h well be5 /yl$ ! ,m$als ( ,creation2 & ! significance ( fossils z guides to ! age ( deposits may p]haps be made cle>] if we pursue ?is comp>ison "s way4 ,9 ! fir/ place !re is cle> indication ( a gradual increase 9 ! complexity ( organisation ( ! fossils z "o passes f ! e>li] to ! lat] rocks1 & accord+ly ! g5]al facies ( a fauna is likely to furni% a clue to ! age ( ! rocks 9 :i* x is f\nd1 ev5 ?\gh e species or ev5 g5us repres5t$ 9 ! fauna 0 previ\sly unkn[n to sci5ce4 ,s an antiqu>y v]s$ 9 ! evolution ( art or metallurgy1 might detect ! g5]al age ( a m$al ) ^: image & sup]scription he 0 n acqua9t$4 ,he w\ld "k t a m$al /ruck 9 iron 0 =m$ subsequ5tly to ! bronze age1 or t "o =m$ ( palladium app]ta9$ to ! pres5t c5tury4 ,b q ap>t f any !oretical k1 an antiqu>y w\ld f9d z ! result ( accumulat$ exp]i5ce t c]ta9 m$als are *>act]i/ic ( c]ta9 p]iods2 he w\ld le>n t ! d5>ius is *>act]i/ic ( a diff]5t p]iod f t indicat$ by ! co9 ( ! ,victorian era1 ev5 ?\gh he _h no k ( ! te*nicalities ( numismatics4 ,! same is ! case ) ! geologi/4 ,he may n be influ5c$ by any k ( ! evolution ( faunas & floras1 b actual "w among/ ! rocks w %[ him t ! trilobite is n f\nd ) ! belemnite or ! i*?yosaur ) ! elephant1 save "u exceptional circum/ances1 :i* only prove ! rule1 z = in/ance :5 worn bones ( i*?yosaurs are wa%$ f _! prop] /rata into gravels ) elephant-bones4 ,x mu/ be di/9ctly und]/ood t ! det]m9ation ( fossils z *>act]i/ic ( diff]5t p]iods is solely made z ! result ( exp]i5ce4 ,no priori reason+ may give "o indication ( ! actual range 9 "t ( a species or g5us2 no "o c say :y ,disc9a has a long range 9 "t1 :il/ t ( ! closely relat$ ,trematis is v limit$4 ,?is be+ ! case1 ! great] ! mass ( evid5ce :i* is accumulat$ z to ! range ( a fossil1 ! great] w be ! value ( t fossil z a clue to ! age ( ! deposit 9 :i* x is f\nd4 ,?is is s important1 t x requires m ?an m]e notice4 ,if a fossil is f\nd 9 abundance 9 a gr\p ( /rata ,b 9 any "o area1 & is n f\nd 9 an und]ly+ gr\p ,a or ov]ly+ gr\p ,c 9 t area aft] prolong$ se>*1 we may confid5tly speak ( ! fossil z *>act]i/ic ( ! /rata ,b 9 t area1 ?\gh )\t fur!r "w1 ! value ( ! fossil z a clue to age 9 o!r areas w\ld be unprov$4 ,x may nev]!less happ51 t aft] m prolong$ se>* 9 ,a or ,c1 9 ! orig9al area a few specim5s ( ! fossil :i* has be5 spok5 ( z *>act]i/ic ( ,b may be f\nd 9 "o or o!r ( !m1 9 small quantity4 ,! value ( ! fossil z "o *>act]i/ic ( ,b w be slightly dim9i%$1 ?\gh only slightly1 z x is n likely to turn up 9 numb]s 9 ! /rata ,a or ,c aft] ! prolong$ se>*4 ,%\ld ! fossil be f\nd also to be *>act]i/ic ( ! /rata ,b 9 areas o!r ?an ! orig9al "o1 x becomes ( m ?an local value1 & if1 aft] mu* /udy x is f\nd to *>act]ise ! same /rata ov] wide areas1 ! cumulative evid5ce n[ obta9$ w r5d] ! fossil peculi>ly important to ! /ratigraphical geologi/4 ,! detection ( *>act]i/ic fossils is n q s simple z might be suppos$ f ! above rem>ks1 = exam9ation ( ! position ( "o fossil w n prove ! contemporaneity ( b$s 9 diff]5t places1 to prove ?is1 all ! evid5ce at our disposal mu/ be consid]$1 = reasons :i* w be pres5tly po9t$ out4 ,z ! result ( accumulat$ k1 we c n[ compile li/s ( *>act]i/ic fossils ( ! major subdivisions ( ! /rata1 :i* are ( _w-wide utility & z our k increases1 we are enabl$ to subdivide ! /rata into m9or divisions ( m ?an local value4 ,:at is a fossil8 ,be=e discuss+ ! value ( fossils z aids to ! /ratigraphical geologi/1 x may be well to make a few obs]vations z to :at con/itutes a fossil4 ,x is difficult to give any concise def9ition1 & z is (t5 ! case 9 geology1 an explanatory p>agraph is ( m value ?an a m]e def9ition4 ,! t]m fossil 0 orig9ally appli$ to any?+ dug up f ! rocks ( ! e>?'s cru/1 & 0 us$ ) ref]5ce to inorganic objects z well z organic rema9s1 = in/ance m9]als 7 spok5 ( z fossils4 ,x is n[ appli$ ess5tially ?\gh n exclusively to relics ( =m] organisms1 ?\gh "o /ill reads ( fossil ra9-drops1 fossil sun-cracks1 & s on4 ,fur!rmore1 ! relics ne$ n necess>ily be p>ts ( ! organism1 ! track ( a worm or a bird's ne/ if emb$d$ 9 ! /rata w\ld be t]m$ a fossil4 ,x is g5]ally agre$ t no %>p l9e c be drawn betwe5 rec5t & fossil organic rema9s :i* is bas$ ^u ! degree ( m9]alisation 7or z x 0 sometimes t]m$ petrifaction7 ( ! relics1 = _m true fossils h n und]gone m9]alisation1 subsequ5t to _! entombm5t4 ,x has be5 sugge/$ t ! "n fossil %\ld be appli$ to organic rema9s :i* h be5 entomb$ by "s process o!r ?an human ag5cy1 b ?is re/riction is undesirable4 ,! /one-implem5t ( ! riv] gravels is z g5u9e a fossil z ! ammonite extract$ f ! *alk1 & ! human relics ( v rec5t date may give in=mation ( a "* q simil> to t suppli$ by o!r rema9s1 = in/ance1 ! occurr5ce ( moa-bones 9 ,new ,zeal& 9 accumulations bel[ ^? conta9+ biscuit-t9s & jam-pots has be5 us$ z a geological argum5t po9t+ to ! ext9ction ( ! moa be=e ! arrival ( ,europeans 9 ,new ,zeal&4 ,! biscuit-t9 "h s]ves all ! purposes ( a fossil1 & !re is no valid reason :y x %\ld n be spok5 ( z su*4 ,?is /atem5t br+s "o to consid] ano!r me?od :i* has be5 adopt$ 9 ord] to sep>ate fossil organisms f rec5t ones1 namely ! "t-te/4 ,?is aga9 is inapplicable1 = no l9e c be drawn betwe5 ! %ell :i* 0 buri$ 9 ye/]day's tidal deposit & t :i* has la9 9 ! /rata ?r\gh geological ages1 & ea* may be equally useful to ! geologi/4 ,:il/1 !n1 we c give no def9ition ( fossil :i* is likely to meet ) g5]al acceptance1 ! t]m c be s us$1 z n to give rise to any d\bts z to its mean+1 & x is g5]ally applicable to any organic relics :i* h be5 emb$d$ 9 any deposit or accumulation by any ag5t human or o!rwise4 ,mode ( occurr5ce ( fossils4 ,x w n be out ( place to say a few words z to ! way 9 :i* fossils are f\nd 9 /rata1 z b$s are (t5 inf]r$ to be unfossilif]\s1 because ( ignorance ( me?ods :i* %\ld be pursu$ 9 se>*+ = organic relics4 ,x is unnecess>y to dilate ^u ! actual modes ( pres]vation ( organisms1 :i* is treat$ ( fully 9 o!r works4 ,9 ! fir/ place1 x is ra% to ass]t t any deposit is unfossilif]\s because no fossils h be5 f\nd 9 x1 ev5 aft] prolong$ se>*4 ,! ,llanb]is slates _h be5 eag]ly se>*$ = fossils = _m ye>s )\t result1 b t ! se>* 0 n exhau/ive 0 prov$ by ! discov]y ( trilobites 9 !m "s ye>s ago4 ,seek]s aft] fossils are r prone to conf9e _! att5tion to /rata :i* are already kn[n to be fossilif]\s ?an to pay mu* att5tion to ^? :i* h hi!rto yield$ no organic rema9s4 ,"s k9ds ( deposits are m (t5 fossilif]\s ?an o!rs4 ,lime/ones :i* are frequ5tly l>gely ( organic orig91 are (t5 ri* 9 rema9s1 & muddy deposits m frequ5tly furni% fossils ?an ^? ( a purely s&y nature4 ,! diff]5ce 9 ! yield is n necess>ily due to ! orig9al inclusion ( m rema9s 9 "o rock ?an 9 ano!r1 b is (t5 caus$ by ! oblit]ation ( =m] relics ow+ to *anges :i* h tak5 place 9 ! rocks subsequ5tly to _! deposition4 ,no s$im5t>y rock mu/ be reg>d$ z unfossilif]\s1 h[ev] unfitt$ x appe>s = ! pres]vation ( fossils4 ,! writ] has se5 fossils1 n only 9 co>se conglom]ates1 rocks :i* frequ5tly conta9 no traces ( organisms1 b 9 deposits compos$ l>gely ( specul> iron ore1 & ev5 9 intrusive igne\s rocks1 ?\gh 9 ! latt] case1 ! inclusion ( fossils 0 due to circum/ances :i* _c h occurr$ ) frequ5cy4 ,9 s&y /rata1 ! sub/ance ( ! fossils has (t5 be5 completely remov$1 leav+ holl[ ca/s1 :i* may be almo/ or q unrecognisable4 ,9 ^! circum/ances1 mu* in=mation may be obta9$ by tak+ impressions ( ! ca/s 9 modell+ wax or "s o!r mat]ial4 ,! importance ( ?is process may be judg$ f ! results x yield$ to ,mr ,clem5t ,reid 9 ! case ( ! fossils ( ! ,plioc5e deposits occurr+ 9 pipe-l holl[s 9 ! ,cretace\s rocks ( ,k5t & ! discov]y ( ! rem>kable reptiles describ$ by ,mr ,e4 ,t4 ,newton f ! ,triassic s&/ones ( ,elg94 ,9 argillace\s rocks :i* h be5 affect$ by ! processes produc+ cleavage1 ! fossils may be di/ort$ beyond recognition or ow+ to ! difficulty ( break+ ! rocks along ! orig9al planes ( deposition1 may rema9 invisible4 ,"u su* circum/ances1 small nodules ( s&y or calc>e\s nature may sometimes be f\nd includ$ 9 ! argillace\s deposits & may p]haps yield fossils4 ,(t5times1 also1 :]e ! argillace\s rock is 9 close proximity to a h>d] rock1 su* z massive grit1 ! argillace\s rock 9 close contiguity to ! h>d rock may escape ! impress ( cleavage-/ructure1 & fossils may be readily extract$ f rocks 9 ?is position :5 n obta9able f o!r p>ts ( ! deposit4 ,x 0 "u ^! circum/ances t ! trilobites allud$ to above 7 obta9$ f ! ,llanb]is slates4 ,! fossils ( calc>e\s rocks are (t5 v obvi\s1 b difficult to extract1 z !y break across :5 ! rock is fractur$4 ,!y are frequ5tly obta9able 9 a p]fect condition :5 ! rock is wea!r$4 ,occasionally !y may be extract$ f c]ta9 argillace\s lime/ones if ! lime/one be heat$ to r$ness1 & sudd5ly plung$ into cold wat]4 ,fossils are (t5 f\nd 9 a /ate :i* enables !m to be readily extract$ :5 a lime/one is co>sely cry/all9e1 ?\gh !y _c be extract$ 9 a p]fect condition :5 ! same lime/one is 9 a diff]5t /ate4 ,_m microzoa1 :i* are invisible 9 rocks1 ev5 :5 view$ ?r\gh a l5s1 may be f\nd 9 microscopic sections ( calc>e\s & silici\s rocks1 & plant /ructures may be detect$ "u simil> circum/ances 9 ! case ( c>bonace\s rocks4 ,v>i\s special me?ods ( extract+ fossils f rocks h be5 describ$ by diff]5t writ]s1 _m ( :i* are v complex1 & require mu* "t4 ,! me*anical action ( ! s&-bla/ & ! solv5t action ( v>i\s acids z hydro*loric & hydr(luosilicic h be5 f\nd ( use ^u diff]5t occasions#aa4 ,! v>i\s processes :i* h be5 utilis$ 9 ord] to extract & develop fossils c1 h[ev]1 be be/ le>n$ by in=mation obta9able f curators ( palontological collections1 & by actual exp]i5ce1 & !re is yet mu* in=mation to be acquir$ z to ! mann] ( extract+ fossils f v>i\s k9ds ( rocks4 ,footnote #aa3 ,= in=mation conc]n+ use ( acids see especially ,wiman1 ,c4 ,ueb] die ,graptolit51 ,bull4 ,geol4 ,in/41 ,upsala1 ,no4 #d1 vol4 ,,ii4 ,"p ,,ii4 ,relative value ( fossils to ! ,/ratigraphical ,geologi/4 ,x has be5 h9t$ above t no g5]al rule z to ! relative value ( fossils z guides to ! age ( /rata c be laid d[n1 & t ! asc]ta9m5t ( _! relative value is l>gely ! result ( actual exp]i5ce4 ,x may be not$1 h[ev]1 t organisms :i* possess h>d p>ts are naturally m important to ! geologi/ ?an ^? :i* d n1 z few traces ( ! latt] are pres]v$ 9 ! fossil /ate1 & ev5 :5 pres]v$ are usually too obscure to be ( mu* practical use4 ,( ! organisms :i* d possess h>d p>ts1 diff]5t gr\ps h be5 utilis$ to a diff]5t degree1 & "o gr\p w be m or less important ?an ano!r1 accord+ to ! use to :i* x is appli$4 ,gr\ps ( organisms :i* h a long range 9 "t are naturally useful = ! id5tification ( l>ge subdivisions ( ! /rata1 :il/ ^? :i* h _h a %ort] range are valuable :5 sep>at+ m9or subdivisions4 ,aga91 z ! bulk ( ! s$im5t>y deposits has be5 =m$ b5ea? ! wat]s ( ! ocean1 relics ( m>9e organisms are naturally m useful ?an ^? ( fre%wat] ones4 ,o!r ?+s be+ equal1 ! m easily ! organism is recognisable1 & ! m abundant are its rema9s1 ! great] its value to ! /ratigraphical geologi/1 & z ! rema9s ( inv]tebrates are usually f\nd 9 great] quantities & 9 m readily recognisable condition ?an ^? ( ! v]tebrates1 !y h be5 us$ m ext5sively z indices ( age4 ,( ! inv]tebrates1 ! mollusca are (t5 v abundant1 _! rema9s are adapt$ = pres]vation1 & _! *>act]i/ics h be5 ext5sively /udi$1 & accord+ly !y h be5 & are ( great use to ! geologi/4 ,( o!r gr\ps1 ! graptolites1 corals1 e*9ids1 bra*iopods1 & trilobites h be5 v l>gely utilis$4 ,! ,l[] ,palozoic /rata h be5 divid$ into num]\s gr\ps1 ea* *>act]is$ by def9ite =ms ( graptolites1 & a simil> use has be5 made ( ! ammonites 9 ! case ( ! ,mesozoic rocks4 ,x is n to be inf]r$ t ^! gr\ps ( organisms are naturally m useful ?an o!r gr\ps1 on acc\nt ( ! ext5t to :i* !y h be5 us$2 we c m]ely /ate t !y h be5 prov$ to be useful z ! result ( prolong$ /udy2 :5 o!r gr\ps h receiv$ equal att5tion1 !y may well be f\nd to be equally useful = ! purposes :i* we h 9 view4 ,contemporaneity & ,homotaxis4 ,f :at has be5 already /at$1 x w be recognis$ t ! ages ( ! v>i\s fossilif]\s rocks ( ! geological column#ab 9 any "o area c be id5tifi$ ) great] or less degree ( c]ta9ty by ref]5ce to _! includ$ organisms1 ! v>i\s subdivisions be+ m>k$ by ! possession ( *>act]i/ic fossils1 & x w be naturally & rightly inf]r$ t ! great] ! numb] ( *>act]i/ic fossils ( any "o deposit1 ! m c]ta9 is ! id5tification ( t deposit4 ,9 practice1 geologi/s are wont to asc]ta9 ! age ( ! /rata aft] consid]ation ( all ! fossils f\nd !re91 "s ( :i* may be actually *>act]i/ic :il/ _m may come up f ! /rata bel[1 or pass into ^? above4 ,hav+ asc]ta9$ ! ord] ( succession & fossil cont5ts ( ! /rata 9 v>i\s regions1 x is ! task ( ! geologi/ to comp>e ! /rata ( ^! two regions1 & ?is task is fraught ) consid]able difficulty4 ,mu* controv]sy has aris5 z to ! degree ( accuracy ) :i* /rata ( remote regions c be correlat$1 & ! subject is "o :i* requires full consid]ation4 ,footnote #ab3 ,al?\gh ! rocks d n always lie on "o ano!r 9 regul> succession1 x is (t5 conv5i5t to speak ( !m z ?\gh !y did1 & z ?\gh a column ( /rata c\ld be c>v$ out 9 any region consi/+ ( horizontal b&s ( deposit "o above ano!r4 ,we speak ( su* an ideal arrangem5t z con/itut+ a 'geological column4' ,suppose t a s]ies ( /rata :i* we w call ,a1 ,b1 & ,c is f\nd 9 any "o area1 ea* memb] ( :i* conta9s *>act]i/ic fossils :i* enable x to be recognis$ 9 t area1 & we w fur!r suppose t 9 ano!r area a s]ies ( /rata ,a1 ,b1 & ,c is discov]$1 ( :i* ,a has ! fauna ( ,a 9 ! =m] area1 & simil>ly ,b ! fauna ( ,b1 & ,c t ( ,c4 ,x _c be assum$ t ! /ratum ,a is !re=e contemporane\s ) ,a1 ,b ) ,b1 & ,c ) ,c1 b on ! o!r h&1 x mu/ n be assum$ t !y are n contemporane\s4 ,?is is a /atem5t :i* requires "s comm5t4 ,x has be5 urg$ t if ! deposits ,a & ,a 9 diff]5t localities conta9 ! same fauna1 ?is is a pro( t ! two are n contemporane\s1 = "s "t mu/ h elaps$ 9 ord] to all[ ( ! migration ( ! organisms f "o area to ano!r1 x be+ ju/ifiably assum$ t !y did n orig9ate simultane\sly 9 ! two areas4 ,b ev]y?+ dep5ds on ! "t tak5 = migration z comp>$ ) ! p]iod ( exi/5ce ( ! fauna4 ,if ! =m] 0 extremely %ort z comp>$ ) ! latt] x may be practically ignor$1 = we might !n speak ( ! /rata z contemporane\s1 j z a hi/orian w\ld rightly speak ( ev5ts 9 ! same way :i* occurr$ ^u ! same aft]noon1 ?\gh "o might h happ5$ an h\r be=e ! o!r4 ,let u !n glance at ! evid5ce :i* we h at our disposal1 :i* be>s ^u ?is matt]4 ,! objection to id5tification ( /rata ) simil> faunas z contemporane\s 0 urg$ by ,:ewell1 ,h]b]t ,sp5c]1 & ,huxley1 & ! latt] sugge/$ ! t]m ,homotaxis or simil>ity ( arrangem5t z applicable to gr\ps ( /rata 9 diff]5t areas1 9 :i* a simil> succession ( faunas 0 traceable1 ma9ta9+ t ?\gh n contemporane\s ! /rata might be spok5 ( z homotaxial4 ,huxley w5t s f> z to ass]t t = any?+ t geology or palontology are able to %[ to ! contr>y1 a ,devonian fauna & flora 9 ! ,briti% ,isl&s may h be5 contemporane\s ) ,silurian life 9 ,nor? ,am]ica1 & ) a ,c>bonif]\s fauna & flora 9 ,africa#ac1 a /atem5t :i* few if any liv+ geologi/s w endorse4 ,if ! /atem5t be true1 & ! fauna :i* we speak ( z ,devonian1 :5 pres5t be always f\nd 7z x is7 above t :i* we 9 ,brita9 "k z ,silurian & bel[ t :i* we t]m ,c>bonif]\s1 ! faunas mu/ h orig9at$ indep5d5tly 9 ! ?ree c5tres1 & disappe>$ be=e ! appe>ance ( ! next fauna1 or hav+ orig9at$ at ! same c5tre1 ea* mu/ h migrat$ 9 ! same direction1 spread ov] ! _w1 & become ext9ct z x rea*$ ! po9t or l9e f :i* x />t$4 ,suppose = in/ance a fauna ,a orig9ates at ! m]idian ( ,gre5wi*1 migrates ea/w>d1 & dies out aga9 :5 x once m rea*es ,gre5wi*1 t ,b & ,c d ! same1 at a lat] p]iod1 !n ! fauna ,b w always be f\nd above ,a & ,c above ,b1 b if ,b did n become ext9ct :5 x rea*$ ! ,gre5wi* m]idian1 x w\ld cont9ue its ea/w>d c\rse1 & ,c hav+ 9 ! meantime />t$ on its fir/ r\nd1 ! fossils ( ! fauna ,b w\ld be f\nd bo? above & bel[ ^? ( ,c4 ,x w be %[n bel[ t cases ( recurr5ce d occur1 b n[h]e d we f9d a ,silurian fauna above a ,devonian "o1 or a ,devonian "o above "o belong+ to ! ,c>bonif]\s1 nor is ! fauna ( a great gr\p ( rocks f\nd 9 "o region above ! fauna ( ano!r gr\p1 & 9 ano!r region bel[ ! same4 ,& ?is is true n only ( ! faunas ( "o major division1 su* z ^? ( ! ,silurian & ,c>bonif]\s p]iods1 b also ( ! faunas ( _m m9or subdivisions into :i* ! l>ge ones are sep>at$1 = in/ance we d n f9d ! ,ll&ov]y fauna ( ! ,silurian p]iod :i* 9 ,brita9 is f\nd bel[ ! ,w5lock fauna emb$d$ else:]e 9 /rata above ! ,w5lock4 ,i h simplifi$ ! /atem5t by assum+ t ! faunas are id5tical 9 ! diff]5t localities1 & exactly simil> ?r\gh\t ! :ole ?ickness ( ! conta9+ /rata1 :i* is naturally n ! case1 b ! additional complexity does n conceal ! tru? ( :at has be5 /at$4 ,9 ! abs5ce ( actual inv]sion ( well-m>k$ faunas1 only "o explanation is possible1 namely1 t ! "t = migration ( =ms is s %ort z comp>$ ) ! entire p]iod dur+ :i* ! =ms exi/$1 t x may be practically ignor$1 & ! /rata conta9+ simil> faunas may be !re=e spok5 ( tru?fully z contemporane\s & n m]ely homotaxial#ad4 ,footnote #ac3 ,huxley1 ,t4 ,h4 ,geological ,contemporaneity & ,p]si/5t ,types ( ,life1 be+ ! ,anniv]s>y ,address to ! ,geological ,society = #ahfb2 repr9t$ 9 ,lay ,s]mons1 ,addresses & ,reviews4 ,footnote #ad3 ,= full] discussion ( ?is matt] see a pap] by ! ,au?or ',on ,homotaxis1' ,proc4 ,camb4 ,phil4 ,soc41 vol4 ,,vi4 ,"p ,,ii4 p4 #gd4 ,app>5t anomalies 9 ! di/ribution ( fossils4 ,!re are sev]al occurr5ces :i* h t5d$ to augm5t ! di/ru/ frequ5tly felt conc]n+ ! value ( fossils z indices ( ! age ( ! b$s 9 :i* !y occur1 :i* may be "h consid]$4 ,?\gh ! great] numb] ( fossil rema9s belong$ to organisms :i* liv$ dur+ ! "t ( accumulation ( ! deposits 9 :i* !y are n[ emb$d$1 ?is is by no means univ]sally ! case1 & ! occurr5ce ( remani fossils1 :i* h be5 d]iv$ f deposits m anci5t ?an ! ones 9 :i* !y are n[ f\nd is f> f be+ a r>e ev5t4 ,! exi/5ce ( rema9s ( ?is nature 9 ! sup]ficial drifts & riv]-gravels ( our own c\ntry has long be5 recognis$1 & no "o w\ld suppose t ! ,grypha & o!r %ells furni%$ by ^! gravels _h liv$ contemporane\sly ) ! species ( ,corbicula1 ,unio & o!r molluscs :i* are "p ( ! true fauna ( ! gravels4 ,9 ?is case ! wat]-worn nature ( ! rema9s is a good index to _! orig91 b 9 o!r cases1 x is by no means an infallible guide1 = we sometimes f9d on ! "o h& t rema9s ( organisms prop] to ! deposits 9 :i* !y occur are wat]-worn1 :il/ on ! o!r ! relics ( remani fossils are n4 ,! n[ well-kn[n gault fossils ( ! ,cambridge ,gre5s& at ! base ( ! *alk 7 n always recognis$ z hav+ be5 d]iv$ f old] b$s1 & !re are c]ta9 fossils f\nd 9 nodules 9 ! ,cretace\s rocks ( ,l9coln%ire1 :i* /ill =m a subject = diff]5ce ( op9ion1 = :ile "s writ]s ma9ta9 t !y belong to ! deposits 9 :i* !y are n[ f\nd1 o!rs suppose t ! nodules h be5 wa%$ out ( e>li] b$s4 ,occasionally we f9d =ms :i* occurr+ 9 a set ( b$s ,a 9 an area1 are abs5t f ! ov]ly+ b$s ,b1 & appe> aga9 9 ! succe$+ deposits ,c4 ,su* cases ( recurr5ce are by no means r>e1 ?\gh _m suppos$ in/ances ( recurr5ce h be5 record$ z ! result ( /ratigraphical or palontological errors4 ,! be/ examples h be5 not$ by ,b>r&e among ! ,l[] ,palozoic deposits ( ,bohemia4 ,! /age ,d ( ,bohemia consi/s ( five 'b&es' or subdivisions1 ! l[e/ 7d #a71 c5tral 7d #c7 & upp]mo/ 7d #e7 divisions are ma9ly argillace\s1 :il/ ! second 7d #b7 & f\r? 7d #d7 are ess5tially ar5ace\s4 ,"s ( ! =ms f\nd 9 d #a1 d #c & d #e h n be5 f\nd 9 d #b & d #d4 ,! be/-kn[n example is ! trilobite gl9a r$iviva4 ,x is cle> t ?is & o!r =ms did n become ext9ct dur+ ! deposition ( ! /rata ( d #b & d #d1 ?\gh !y may h disappe>$ tempor>ily f ! ,bohemian area1 or else l+]$ on 9 su* dim9i%$ numb]s t _! rema9s h n be5 discov]$4 ,! range ( ! organism is 9 fact "r ?r\gh ! deposits ( ! /age ,d1 & ! discont9uity ( di/ribution is n a real anomaly2 x may be comp>$ to "s ext5t ) cases ( discont9u\s di/ribution 9 space4 ,x is ne$less to rem>k t ! :ole fauna does n disappe> = a "t & !n reappe>1 b only a few out ( ! _m =ms :i* compose x4 ,! comp>ative r>ity ( examples ( recurr5ce aft] long int]vals is an indication t ! palontological record z x is t]m$ is n s imp]fect z "s suppose1 = if our k ( fossils 7 v imp]fect1 we %\ld expect cases ( app>5t recurr5ce to be common1 z ! result ( ! non-detection ( fossils 9 ! int]m$iate b$s4 ,"o ( ! mo/ m>k$ cases ( app>5t recurr5ce kn[n "s ye>s ago 0 ! reappe>ance ( a g5us ( trilobite ,ampyx 9 ,ludl[ rocks1 f\nd 9 ! ,bala rocks1 b n 9 ! ,ll&ov]y or ,w5lock /rata4 ,x has s9ce be5 discov]$ 9 ,ll&ov]y b$s1 & its ev5tual discov]y 9 b$s ( ,w5lock age may be reg>d$ z c]ta94 ,a suppos$ case ( recurr5ce :i* w\ld h be5 rem>kable1 t ( ! disappe>ance ( ,phillipsia 9 ,ordovician rocks1 its entire abs5ce 9 ^? ( ,silurian age1 & its reappe>ance 9 ! ,devonian1 has brok5 d[n1 = ! suppos$ ,ordovician =m has be5 %[n to belong to an entirely diff]5t gr\p ( trilobites f t conta9+ ! g5us ,phillipsia1 & x has be5 !re=e r5am$ ,phillips9ella4 ,_m app>5t anomalies ( di/ribution h be5 expla9$ z due to migration1 b x is d\btful :e!r any "o ( ^! suppos$ anomalies is actual & n due to errors 9 det]m9+ ! position ( ! b$s or ! nature ( _! includ$ fossils4 ,"s ( ! suppos$ anomalies h already be5 %[n to be due to error1 & ! o!rs w almo/ c]ta9ly be cle>$ up4 ,9 speak+ ( anomalies ( di/ribution1 ! geologi/ c only be guid$ by exp]i5ce z to :at con/itutes an anomaly4 ,= in/ance ! exi/5ce ( a complete fauna 9 any "o place 9 ! b$s ( a sy/em above t to :i* x is else:]e conf9$ w\ld be reg>d$ z anomal\s & z probably due to error1 :il/ ! reappe>ance ( sev]al =ms 9 b$s ( a sy/em high] ?an t 9 :i* !y _h hi!rto be5 f\nd1 c\ld h>dly be consid]$ z an anomaly4 ,a geologi/ w\ld suspect ! /atem5t t aft] ! disappe>ance ( an ,ordovician fauna 9 an area & its replacem5t by a ,silurian fauna1 ! ,ordovician fauna reappe>$ = a "t1 b w\ld n reg>d ! /atem5t t a ,c5omanian fauna p>tly reappe>$ 9 ! ,*alk ,rock ) surprise4 ,! exi/5ce ( a ,silurian fauna 9 ,ordovician times 0 ma9ta9$ by ,b>r&e 9 ! case ( ! ,bohemian bas94 ,l5ticul> pat*es ( ,silurian rocks hav+ ! li?ological *>act]s ( ! ,silurian /rata are f\nd 9 ! ,ordovician b$s ( t region1 & !y conta9 fossils specifically id5tical ) ^? ( ! ,silurian rocks4 ,b>r&e expla9$ ?is appe>ance z due to ! exi/5ce ( a fauna 9 o!r regions resembl+ ! ,silurian fauna ( ,bohemia1 dur+ ! ,ordovician p]iod1 :5 ! normal ,ordovician fauna ( ,bohemia inhabit$ t area4 ,he suppos$ t 9 p>ts ( ! bas91 :5 fav\rable conditions arose1 colonies ( ! =eign fauna settl$ = a "t1 b did n get a p]man5t foot+ 9 ! bas9 until ! comm5cem5t ( ,silurian times4 ,! !ory ( colonies has n[ be5 reject$ = ! ,bohemian area1 & ! ph5om5a %[n to be due to repetition ( /rata by fold+ & fault+1 b x is a !ory :i* is aga9 & aga9 advocat$ 9 ord] to expla9 app>5tly anomal\s ph5om5a 9 o!r areas1 & ^! app>5t anomalies :i* are s expla9$1 mu/ be reg>d$ ) grave suspicion4 ,! v>i\s complexities allud$ to 9 ! =ego+ pages increase ! difficulty exp]i5c$ by ! geologi/ 9 correlat+ /rata 9 diff]5t areas by _! includ$ organisms1 b no "o ( !m disproves ! possibility ( mak+ ^! correlations1 :i* c be c>ri$ on to a great] or less ext5t accord+ to ! nature ( ! faunas4 ,a good deal ( misconception has aris5 conc]n+ ! geographical di/ribution ( =m] faunas1 ow+ to ! t5d5cy to comp>e !m exclusively ) ! littoral faunas ( ! pres5t day4 ,^! littoral faunas h a comp>atively limit$ geographical di/ribution1 ! =ms ( "o m>9e prov9ce (t5 diff]+ consid]ably f ^? ( an adjo9+ "o1 & /ill m widely f "o :i* is remote1 s t anyone confront$ ) ! relics ( faunas f ! exi/+ ,au/ralian & ,european seas1 w\ld f9d no indications furni%$ by id5tity ( species t ! faunas 7 contemporane\s4 ,rec5t rese>*es h %[n1 h[ev]1 t ! creatures ^: rema9s are deposit$ at "s di/ance f ! coa/-l9e h a mu* /rong] resemblance to "o ano!r ?an ! littoral organisms h1 if ! fauna ( two di/ant areas be comp>$4 ,x is /ill a moot po9t :i* w be discuss$ 9 a lat] *apt]1 h[ f> ! deep-sea deposits ( mod]n times are repres5t$ among/ ! /rata ( ! geological column by deposits ( simil> orig94 ,b x is c]ta9 t _m ( ! anci5t /rata are n littoral deposits1 & x w be f\nd t x is by comp>ison ( ! faunas ( ! deep]-wat] deposits t ! geologi/ correlates ! /rata ( remote regions3 :]e %all[ wat] deposits are =m$1 ! faunas diff] m>k$ly 9 diff]5t regions1 & ^! %all[-wat] =ms c only be correlat$ ow+ to _! occurr5ce betwe5 deep]-wat] /rata4 ,?us if /rata ,a1 ,b & ,c be f\nd 9 "o area1 & ! fauna ( ,a & ,c are deep-wat] =ms1 ^? ( ,b be+ %all[-wat] =ms1 & 9 ano!r area b$s ,a conta9 ! same fauna z ,a1 & ,c ! same fauna z ,c :il/ ! fauna ( ,b is diff]5t f t ( ,b1 we c nev]!less correlate ! /rata ,b & ,b 7if !y be con=mable ) ! und]ly+ & ov]ly+ b$s71 because ( ! id5tity ( age ( ! associat$ b$s 9 ! two areas4 ,x w possibly be f\nd t ! /rata ,a & ,c c be fur!r subdivid$ into ,a#a1 ,a#b1 444 c4 ,c#a1 ,c#b1 444 by ! exi/5ce ( m9or faunas1 :i* are comp>able 9 ! two cases1 b su* subdivisions may n be e/abli%$ 9 ! case ( ! b$s ,b & ,b4 ,to take actual examples3--,! ,ll&ov]y b$s ( ,dumfries%ire c be subdivid$ into sev]al m9or divisions ea* ( :i* c be recognis$ 9 ! ,lake ,di/rict ( ,engl&1 & to a l>ge ext5t 9 ,sc&9avia & else:]e1 = ! deposits 9 ^! areas are ( deep-wat] "*1 & ! sub-faunas ( ! subdivisions are simil> 9 ! diff]5t areas1 b ! ,ll&ov]y rocks ( ! ,wel% bord]l& are %all[-wat] deposits1 ) a diff]5t fauna f t ( ! deep-wat] deposits ( ?is age1 & c only be /at$ to be contemporane\s ) ! ,ll&ov]y rocks else:]e1 because ! deep]-wat] faunas ( ! und]ly+ ,bala rocks & ov]ly+ ,w5lock rocks ( ! ,wel% bord]s are respectively simil> to ^? ( ! ,bala & ,w5lock rocks ( ! o!r regions4 ,! %all[-wat] ,ll&ov]ies ( ! ,wel% bord]s h only be5 sep>at$ into two divisions1 upp] & l[]1 & h n be5 split up into a numb] ( subdivisions1 ea* *>act]is$ by a sub-fauna1 & ea* comp>able ) "o ( ! subdivisions ( ,dumfries%ire1 ,lakel& & ! o!r regions :]e ! deep-wat] facies is f\nd4 ,x w be se5 t ?\gh ! pr9ciple ( ,william ,smi? t /rata c be recognis$ by _! includ$ organisms has be5 ext5d$ s9ce 8 "t1 & %[n to apply to f> small] subdivisions ( ! /rata ?an 0 suspect$1 ! me?od ( application is ! same1 & is m or less successful accord+ to ! am\nt ( evid5ce :i* is accumulat$ 9 support ( x4 ,,*apt] ,,vi4 ,,me?ods ,,( ,,classification ,,( ,,! ,,/rata4 ,e>?-hi/ory l human hi/ory is ! record ( an unbrok5 *a9 ( ev5ts4 ,! ag5ts :i* h produc$ geological ph5om5a h be5 9 op]ation s9ce ! e>? came into exi/5ce4 ,accord+ly a p]fect e>?-hi/ory w\ld be writt5 z a cont9u\s n>rative1 j z w\ld a complete hi/ory ( ! human race4 ,! hi/orian ( man f9ds x n only conv5i5t b necess>y to divide ! epo* ( :i* he is writ+ into p]iods ( "t1 & s does ! geologi/1 & 9 ea* case ! division is necess>ily m or less arbitr>y4 ,x is true t 9 writ+ ! hi/ory or geology ( a c\ntry1 m>k$ ev5ts /& out :i* =m a conv5i5t means ( mak+ divisions1 b ! m>k$ ev5ts occurr+ 9 "o c\ntry are n likely to take place simultane\sly ) ^? ( ano!r c\ntry1 & consequ5tly a classification ( ?is "* is only locally applicable4 ,! classification :i* is at pres5t us$ by geologi/s 0 orig9ally f\nd$ ^u def9ite pr9ciples1 & al?\gh our pr9ciples ( classification h1 z w appe>1 be5 some:at alt]$ subsequ5tly1 x has be5 f\nd m conv5i5t to modify ! orig9al classification ?an to adopt a new "o 9 its entirety4 ,! l>ge/ divisions into :i* ! /rata ( ! geological column 7 sep>at$ 7 in/itut$ because ( ! suppos$ ext9ction ( faunas1 & sudd5 or rapid replacem5t by o!r faunas ( an entirely diff]5t "*4 ,?is suppos$ rapid ext9ction & replacem5t is n[ kn[n to h be5 only app>5t & due to obs]vation 9 re/rict$ areas1 & x is d\btful :e!r ! ?ree great divisions f\nd$ ^u !m are n r mis*iev\s ?an useful1 z t5d+ to dissem9ate wrong notions4 ,moreov] !re is consid]able div]sity ( op9ion z to ! t]ms to be adopt$4 ,! rocks 7 =m]ly divid$ into ,prim>y1 ,second>y1 & ,t]ti>y4 ,ow+ *iefly to ! use ( ! t]m ,prim>y 9 ano!r s5se1 ! alt]native titles ,palozoic1 ,mesozoic & ,ca9ozoic 7or ,cnozoic7 7 sugge/$1 & ?\gh ! t]m ,prim>y has be5 def9itely ab&on$ 9 fav\r ( ,palozoic1 ! words ,second>y & ,t]ti>y are us$ ext5sively z synonyms ( ,mesozoic & ,ca9ozoic4 ,x 0 soon p]ceiv$ t ! p]iod ( "t includ$ 9 ! ,palozoic age 0 mu* long] ?an ! comb9$ p]iods ( ,second>y & ,t]ti>y ages1 & x 0 propos$ to gr\p ! latt] "u "o title ,neozoic1 :il/ ano!r sugge/ion 0 to split ! ,palozoic age into an e>li] ,prot]ozoic & lat] ,deut]ozoic division4 ,! int]e/ excit$ by ! adv5t ( man is probably ! cause ( ! attempt to e/abli% a ,quat]n>y division1 :i* "s hold to be a m9or subdivision ( ! ,t]ti>y1 :il/ o!rs w\ld sep>ate x altoge!r4 ,! t]ms ,palozoic1 ,mesozoic 7or ,second>y7 & ,ca9ozoic 7or ,t]ti>y7 are n[ us$ s g5]ally t any attempt to aboli% !m w\ld be doom$ to failure1 b x mu/ be rememb]$ t !y are purely arbitr>y expressions1 & ! o!r t]ms :i* are n 9 g5]al use1 might be dropp$ ) advantage4 ,! o!r subdivisions h be5 us$ some:at loosely1 & al?\gh an attempt has be5 made by ! ,int]national ,geological ,congress to re/rict c]ta9 names to subdivisions ( v>y+ degrees ( value1 x w probably be f\nd be/ to all[ ( a c]ta9 ela/icity 9 ! use ( t]ms1 m]ely agree+ t !y %all be us$ z ne>ly z possible ) ! signification assign$ to !m by ! ,congress4 ,accord+ to ?is classification1 & ap>t f ! division into ,palozoic1 ,mesozoic & ,ca9ozoic1 ! /rata ( ! geological column are gr\p$ into ,sy/ems1 :i* are subdivid$ into ,s]ies1 & ! s]ies are fur!r split up into ,/ages4 ,a numb] ( *ronological t]ms 7 also sugge/$1 ( equival5t importance1 ?us ! b$s ( a sy/em w\ld be deposit$ dur+ a ,p]iod1 ^? ( a s]ies dur+ an ,epo*1 & ^? ( a /age dur+ an ,age#ae4 ,footnote #ae3 ,! *ronological words h be5 us$ s loosely t x is d\btful :e!r any good w come ( try+ to re/rict _! use1 & ,sir ,a4 ,geikie has po9t$ out ! confusion :i* w\ld arise if ! t]m gr\p be employ$ = ! l>ge/ divisions 7,palozoic1 c474 ,! t]ms ,sy/em1 ,s]ies & ,/age may well be employ$ 9 ! s5ses sugge/$ by ! ,congress4 ,! rocks ( ! ,geological ,column 7 orig9ally divid$ into sy/ems1 ow+ to ! occurr5ce ( m>k$ physical & palontological breaks betwe5 ! rocks ( two adjac5t sy/ems1 except 9 cases :]e a complete *ange occurr$ locally 9 ! li?ological *>act]s ( ! rocks ( two sy/ems :i* 7 9 juxtaposition3 x is necess>y to consid] = a:ile ! nature ( ^! breaks4 ,! mo/ app>5t physical break is :]e ! rocks ( "o set ( deposits re/ uncon=mably ^u ! rocks ( ano!r "o1 indicat+ t ! old] set has be5 uplift$ & to "s ext5t erod$ be=e ! deposition ( ! /rata ( ! new] set4 ,?is uplift & erosion signifies a *ange f oceanic to cont95tal conditions 9 ! area 9 :i* uncon=mity is f\nd on a l>ge scale1 & accord+ly a long p]iod ( "t w\ld elapse dur+ :i* ! cont95tal surface w\ld n receive deposits1 s t ! highe/ rocks ( ! und]ly+ sy/em w\ld be consid]ably old] ?an ! l[e/ rocks ( ! "o :i* succe$s x4 ,su* a break may be obvi\sly utilis$ = purposes ( classification1 b z "s areas ( ! e>?'s surface mu/ h be5 occupi$ by ! wat]s ( ! ocean :5 o!r regions =m$ l&1 deposit 9 "s areas mu/ con/antly h occurr$ simultane\sly ) d5udation 9 o!rs1 & any classification f\nd$ ^u ! exi/5ce ( uncon=mities w !re=e h a purely local value4 ,ano!r1 & less app>5t physical break1 :i* w also be locally applicable1 may be due to ! depression ( an area to s great a dep? t little or no deposit 0 =m$ ^u ! ocean floor !re dur+ ! p]iod ( great depression2 b z a break ( ?is "* is difficult to detect1 ! exi/5ce ( uncon=mities has alone be5 practically utilis$ z a means ( sep>at+ /rata into sy/ems ow+ to m>k$ physical *ange1 except 9 ! cases :]e ! li?ological "* ( ! /rata completely *anges1 z betwe5 ! ,triassic & ,jurassic rocks ( ,engl&4 ,illu/ration3 ,fig4 #b4 ,palontological breaks or breaks 9 ! succession ( organisms are 9 _m cases1 ! result ( physical breaks1 & accord+ly x is (t5 possible to sep>ate "o set ( /rata f ano!r by ! exi/5ce ( a comb9$ physical & palontological break betwe5 !m4 ,x is by no means necess>y h[ev] t a physical break %\ld be accompani$ by a break 9 succession ( ! organisms1 & ! latt] may also occur )\t ! =m]4 ,x 0 once ma9ta9$ t a palontological break 0 due to ! complete & sudd5 ext9ction ( a fauna & its entire replacem5t by a new "o1 b ?is is f> f true1 & accord+ly ! breaks diff] 9 degree4 ,/udy ( ! /rata %[s t :5 ! succession is n to any ext5t int]rupt$1 ! species d n appe> simultane\sly1 b come 9 at diff]5t horizons1 & !y disappe> 9 ! same way4 ,9 ,figure #b let ,a repres5t a set ( con=mable /rata ab 444 k1 & suppose ! v]tical l9es repres5t ! ranges ( ! v>i\s species f\nd 9 ^! /rata4 ,x w be se5 t ( #bg species ^: range is %[n only #b pass ?r\gh ! :ole ?ickness1 s t ! fauna ( k is v diff]5t f ! fauna ( a1 nev]!less ! fauna ( ea* /ratum is closely simil> to t ( ! und]ly+ z well z to t ( ! ov]ly+ /ratum1 & ?\gh mo/ ( ! species ( k are diff]5t f ^? ( a1 ?is ne$ n be ! case ) ! g5]a4 ,! fauna ( ! set ( /rata w\ld conta9 e species ^: range is repres5t$1 & = conv5i5ce' sake x might be said to be compos$ ( sub-faunas1 "o ( :i* occurs 9 ea* division ab 4441 b ! sep>ation into sub-faunas w\ld be artificial & m]ely = conv5i5ce' sake1 = !re is no break betwe5 any two sub-faunas4 ,turn+ n[ to ,b 7,fig4 #b71 an attempt is made !re to %[ :at happ5s :5 !re has be5 a physical break1 result+ 9 ! d5udation ( ! /rata ghik1 & ! deposition ( ano!r set op 444 uncon=mably ^u ^? deposits ( ! e>li] set :i* h n be5 d5ud$4 ,z ! result ( ?is we note1 fir/1 t ! relics ( organisms :i* exi/$ 9 ! area dur+ ! deposition ( ghik1 & 7 entomb$ 9 ^? /rata1 are de/roy$ by ! processes ( d5udation1 & a l>ge numb] ( organisms :i* liv$ long aft] ! deposition ( f1 & disappe>$ n simultane\sly b at diff]5t times dur+ ! p]iod :5 d5udation 0 9 op]ation1 seem to become ext9ct simultane\sly at ! top ( f1 ?\gh1 if we c\ld visit an area :i* 0 receiv+ s$im5t dur+ ! p]iod ( d5udation1 we %\ld f9d !m dy+ out 9 ! rocks ( t region at diff]5t levels4 ,fur!rmore1 :il/ d5udation is go+ on1 a long] or %ort] p]iod ( "t elapses1 dur+ :i* ! upheav$ area receives no deposit1 & accord+ly no organisms :i* liv$ dur+ t p]iod are pres]v$ 9 ! upheav$ area4 ,dur+ ?is "t a set ( deposits lmn may h be5 laid d[n else:]e1 & besides ! gradual disappe>ance ( "s ( ! organisms ( ab 444 k1 !re w h be5 a gradual appe>ance ( new species4 ,:5 ! upheav$ area is once m subm]g$1 a new set ( deposits op 444 is accumulat$ 9 x1 & ! species :i* gradually appe>$ 9 adjo9+ regions w n[ migrate to x1 & w seem to come 9 simultane\sly at ! bottom ( o2 accord+ly we may f9d t !re is n a s+le species :i* passes ?r\gh f f to o & ! palontological break 9 ?is area is complete1 ?\gh x is cle> t x only implies local *ange1 & t we may & inde$ mu/ f9d int]m$iate =ms 9 o!r regions :i* fill up ! gap4 ,z an illu/ration ( ! local "* ( a palontological break we may cite ! case ( ! ,c>bonif]\s & ,p]mian sy/ems ( ,brita94 ,^! rocks are sep>at$ f "o ano!r 9 our area by a physical & palontological break1 b 9 p>ts ( ,india1 & o!r places1 we f9d a gr\p ( rocks n[ kn[n z ! ,p]mo-,c>bonif]\s rocks :i* conta9 a fauna int]m$iate 9 "* betwe5 ^? ( ! ,p]mian & ,c>bonif]\s sy/ems1 & a /udy ( ?is fauna %[s t ! hiatus :i* exi/s locally is fill$ by ! species conta9$ 9 ! ,p]mo-,c>bonif]\s rocks4 ,a palontological break may1 l a physical "o1 result f depression ( ! ocean-floor to s great a dep?1 t no organisms are pres]v$ !re dur+ ! p]iod ( great depression1 & ! rem>ks made conc]n+ a depression ( ?is nature :5 speak+ ( physical breaks w apply "h also4 ,a local palontological break may result ow+ to physical *anges )\t ! production ( an uncon=mity 9 ! area1 or its subm]g5ce to a great dep?1 or if an uncon=mity is f\nd1 ! break may be m m>k$ ow+ to o!r physical *anges4 ,! diff]5ce betwe5 ! ,upp] & ,l[] ,c>bonif]\s faunas is v m>k$ 9 ,engl&1 :]e ! ,upp] ,c>bonif]\s b$s 7 deposit$ "u physical conditions diff]5t f ^? ( ! ,l[] ,c>bonif]\s1 & accord+ly ! corals1 cr9oids & o!r op5-wat] animals :i* fl\ri%$ 9 ,l[] ,c>bonif]\s times are r>e or altoge!r abs5t 9 ! high] rocks4 ,:]e ! *ange ( conditions did n occur to a great ext5t z 9 p>ts ( ,spa9 & ,nor? ,am]ica1 ! simil>ity betwe5 ! two faunas is mu* m pron\nc$4 ,aga91 !re is an uncon=mity betwe5 ! ,cretace\s & ,eoc5e b$s ( ,engl&1 :i* is accompani$ by a palontological break1 b ?is break is m pron\nc$ ow+ to diff]5ce ( physical conditions1 = we f9d abundance ( ga/ropods 9 ! l[] ,t]ti>y b$s1 & a r>ity ( ^! %ells at ! top ( ! *alk ( ,engl&1 ?\gh :]e physical conditions 7 fav\rable = ! gr[? ( ga/ropods1 _! %ells are f\nd 9 ! high] /rata ( *alk age1 & ! palontological break is n s app>5t4 ,a palontological break may occur also z ! result ( climatic *ange1 ?\gh actual in/ances ( ?is occurr5ce are mu* m difficult to detect ow+ to ! g5]al abs5ce ( any evid5ce ( climatic *ange o!r ?an t suppli$ by ! organisms !mselves4 ,/ill1 :5 no physical break exi/s1 & ! li?ological *>act]s ( a gr\p ( s$im5ts rema9 con/ant ?r\gh\t1 indicat+ ! preval5ce ( simil> physical conditions ?r\gh ! p]iod ( deposition ( ! s$im5ts1 if ! fauna sudd5ly *anges1 !re mu/ h be5 cause = ! *ange1 & 9 ! abs5ce ( any o!r cause :i* is likely to produce ! *ange1 alt]ation ( ! "* ( ! climate may be suspect$4 ,x foll[s f ! obs]vations :i* h be5 made1 t al?\gh ! rocks ( ! ,geological ,column may be divid$ into sy/ems ow+ to ! exi/5ce ( physical & palontological breaks1 & ?is classification may be & has be5 appli$ g5]ally1 ! l9e ( dem>cation betwe5 ! rocks ( two sy/ems w be a purely conv5tional "o1 :]e !re is no break1 &1 to avoid confusion1 t l9e :5 once drawn %\ld be adopt$ by ev]yone1 unless good cause c be %[n = its ab&onm5t4 ,! subdivision ( sy/ems into s]ies has be5 conduct$ 9 a mann] g5]ally simil> to t 9 :i* l>ge masses ( /rata h be5 gr\p$ into sy/ems1 ) ! exception t actual breaks ne$ n occur4 ,! subdivision 0 usually made on acc\nt ( m>k$ diff]5ces 9 ! li?ological *>act]s or fossil cont5ts ( ! rocks ( ! v>i\s s]ies1 & frequ5tly ! li?ological *>act]s z well z ! fossil cont5ts are dissimil>2 tak+ ! rocks ( ! ,silurian sy/em ( ! typical ,silurian area z an example1 we f9d ! ,ll&ov]y rocks l>gely ar5ace\s1 ! ,w5lock rocks l>gely calc>eo-argillace\s1 & ! ,ludl[ rocks argillaceo-ar5ace\s1 :il/ ! fauna ( ! ,w5lock rocks diff]s f t ( ! ,ll&ov]y rocks bel[ & also f t ( ! ,ludl[ rocks above4 ,! ,ll&ov]y1 ,w5lock & ,ludl[ !re=e con/itute ?ree s]ies ( ! ,silurian sy/em1 b ! l9es ( dem>cation betwe5 ^! s]ies are nev]!less conv5tional1 = x has be5 sugge/$ t a m natural division1 z f> z ! ,briti% rocks are conc]n$1 c\ld be made by draw+ a l9e1 n z at pres5t at ! base ( ! ,ludl[1 b 9 ! middle ( t s]ies z n[ def9$1 & unit+ ! ,l[] ,ludl[ b$s ) ! ,w5lock /rata to =m a s+le s]ies4 ,! same process z t adopt$ 9 ! case ( s]ies has be5 ess5tially pursu$ 9 subdivid+ ^! into /ages4 ,ea* /age is usually diff]5t f t above & bel[ 9 its li?ological *>act]s1 fossil cont5ts1 or bo?1 ?\gh ! diff]5ce is usually less 9 degree ?an t :i* has be5 utilis$ = ! dem>cation ( s]ies4 ,a /age is (t51 ?\gh n always1 compos$ ( deposits ( "o k9d ( s$im5t1 & is fur!rmore frequ5tly *>act]is$ by ! possession ( "o or1 x may be1 two1 ?ree or m *>act]i/ic fossils4 ,?us ! ,w5lock s]ies is divid$ 9 ! typical area into ,woolhope lime/one1 ,w5lock %ale1 & ,w5lock lime/one1 & ! v names giv5 to ^! /ages indicate t ea* is l>gely compos$ ( "o k9d ( mat]ial4 ,_! fossils are also to "s ext5t diff]5t1 ?\gh ! diff]5ce betwe5 !m is n likely to be ( s m>k$ a nature z t :i* exi/s betwe5 ! faunas ( sep>ate s]ies4 ,x w be se5 t ! sy/em diff]s f ! s]ies & ! s]ies f ! /age 9 degree r ?an 9 k9d1 & no h>d l9e c be drawn betwe5 divisions ( diff]5t degrees ( magnitude4 ,x foll[s !re=e t frequ5tly a mass ( s$im5t :i* "o au?or w consid] suffici5tly important to con/itute a sy/em w be def9$ by ano!r z a s]ies1 & simil>ly a s]ies ( "o writ] may become a /age ( ano!r4 ,! /ud5t ( ,/ratigraphical ,geology w f9d ! expression 'fossil zone' occurr+ ov] & ov] aga9 9 geological lit]ature1 & z ! t]m has be5 us$ some:at vaguely by _m writ]s & is apt to be misund]/ood1 x w be useful to notice ! expression at "s l5g?4 ,/rictly speak+ ! t]m zone 7a belt or girdle71 :5 appli$ to di/ribution ( fossils1 %\ld ref] to ! belt ( /rata ?r\gh :i* a fossil or gr\p ( fossils ranges4 ,g5]ally speak+1 ! expression is us$ 9 connexion ) "o fossil2 ?us we speak ( ! zone ( ,co5ograptus gracilis1 ! zone ( ,cid>is florigemma & ! zone ( ,belemnites jaculum1 ?\gh sometimes x is us$ ) ref]5ce to m ?an "o species1 z ! zone ( ,micra/]s & ! ,ol5ellus zone4 ,! t]m has be5 us$ n ( a belt ( /rata b ( a gr\p ( organisms#af1 & zones def9$ z assemblages ( organic rema9s ( :i* "o abundant & *>act]i/ic =m is *os5 z an index1 b if x be agre$ t ! t]m %\ld be appli$ to /rata & n to organisms ?is might be modifi$ & ! def9ition run3--',zones are belts ( /rata1 ea* ( :i* is *>act]is$ by an assemblage ( organic rema9s ( :i* "o abundant & *>act]i/ic =m is *os5 z an index4' ,footnote #af3 ,see ,h4 ,b4 ,woodw>d1 ,on ,geological ,zones1 ,proc4 ,geol4 ,assoc41 vol4 ,,xii4 ,"p #g1 p4 #bie1 & vol4 ,,xii4 ,"p #h1 p4 #cac4 ,x has be5 object$ t ! subdivision ( /rata into zones has be5 pu%$ too f>1 b ?is is m]ely because 9 ! e/abli%m5t ( zones1 work]s f9d x easi] to "w out ! successive zones :]e ! /rata are ?9 & presumably deposit$ ) extreme sl[ness1 ?an :]e !y are mu* ?ick] & h be5 rapidly accumulat$1 & accord+ly1 z ! subdivision ( /rata into zones is a rec5t ev5t1 geological lit]ature conta9s _m m ref]5ces to ?9 zones ?an to ^? ( great ?ickness4 ,:]e an abundant & *>act]i/ic =m 7:i* is *os5 z an index7 ( an assemblage ( organic rema9s ranges ?r\gh a great ?ickness ( deposit1 !re is no objection to speak+ ( ! :ole z a zone1 & x _c be divid$4 ,to give "s idea ( ! v>iations 9 ! ?ickness ( /rata ?r\gh :i* ^! abundant & *>act]i/ic =ms w range1 ,i app5d a li/ ( ! zones ( graptolites :i* h be5 e/abli%$ among/ ! ,silurian rocks ( ,engli% ,lakel& & ! ?ickness ( ea* 7:i* 9 ! case ( ! ?ick] deposits is naturally only approximate73-- ,?ickness4 ,zone ( ,feet4 ,in*es4 ,monograptus le9tw>d95sis #ejjj #j ,monograptus bohemicus #ejjj #j ,monograptus ,nilssoni #ajjj #j ,cyrtograptus ,mur*isoni #ajjj #j ,monograptus crispus #bb #j ,monograptus turriculatus #fj #j ,ra/utes maximus #be #j ,monograptus sp9ig]us #c #j ,monograptus ,cl+ani #c #j ,monograptus convolutus #g #f ,monograptus arg5teus #j #h ,monograptus fimbriatus #g #f ,dimorphograptus conf]tus #be #j ,diplograptus acum9atus #b #f ,x mu/ n be suppos$ t ea* ( ! subdivisions 9 ! above li/ is ( equal importance1 & has occupi$ approximately ! same l5g? ( "t = its =mation1 b a /udy ( ! /rata proves by v>i\s k9ds ( evid5ce t ! deposits 9 :i* ! *>act]i/ic =ms range ?r\gh a small ?ickness ( rock 7 on ! :ole deposit$ mu* m sl[ly ?an :]e ! range is cont9u\s ?r\gh a great ?ickness ( deposit4 ,! geological sy/ems1 z orig9ally f\nd$1 7 n v accurately sep>at$ f "o ano!r except locally4 ,a compreh5sive view ( ! *>act]s ( a sy/em 0 tak51 & accord+ly ! l9es ( dem>cation betwe5 ! same sy/ems adopt$ by work]s 9 diff]5t c\ntries 7 by no means necess>ily at or ne> ! same geological horizon4 ,z ! result ( m rec5t "w1 ! e/abli%m5t ( fossil zones has be5 gr[+ apace1 & ?\gh _m ( ^! are se5 to h only local significance1 x is f\nd z ! result ( exp]i5ce t _m ( !m are widely spread & occur 9 ! same ord] 9 diff]5t localities2 accord+ly ! rem>ks t h be5 made conc]n+ ! contemporaneity ( /rata apply to ^! zones also4 ,aft] a /udy ( ?is k9d1 a mu* m accurate comp>ison ( /rata is possible1 & correlation ( /rata c be c>ri$ on to a mu* great] ext5t ?an :5 ! sy/ems 7 only r\ghly subdivid$ by ref]5ce to breaks1 diff]5ces ( li?ological "*1 & g5]al comp>ison ( ! faunas2 accord+ly :il/ l>gely reta9+ ! old names1 ! old me?od ( classification is be+ p>tly sup]s$$1 & ! includ$ faunas alone are utilis$ to e/abli% accurate correlations ( ! /rata 9 v>i\s p>ts ( ! _w4 ,h[ f> ?is correlation c be c>ri$ on rema9s to be se51 = ! "w ?\gh well advanc$ has by no means rea*$ completion1 & pr$ictions z to ! ultimate issue are useless )\t ! exp]i5ce by means ( :i* only ! "w c be done4 ,! diff]5ce betwe5 ! me?ods ( classification is well %[n by an exam9ation ( ! old & new divisions ( ! *alk4 ,x 0 =m]ly r\ghly divid$ ma9ly by li?ological *>act]s into ,*alk ,m>l1 ,l[] ,*alk )\t fl9ts1 ,middle ,*alk ) few fl9ts & ,upp] ,*alk ) _m fl9ts1 b no two obs]v]s w\ld probably agree z to :]e ! deposit ) few fl9ts ceas$ & t ) _m comm5c$4 ,! *alk is n[ sep>at$ on palontological gr\nds into ,c5omanian1 ,turonian1 ,s5onian & ,danian1 & ! sup]iority ( ! new me?od to ! old is practically %[n by ! ab&onm5t ( ! old classification except = v r\gh purposes1 & ! g5]al acceptance ( ! new "o4 ,_m o!r examples might be giv51 b ?is "o w suffice4 ,9 ! case ( "s ( ! sy/ems1 ! ,c>bonif]\s = example1 ! old classification f\nd$ ^u li?ological *>act]s is l>gely extant1 & x has be5 inf]r$ !re=e t no accurate subdivisions ( ! ,c>bonif]\s rocks c be made by ref]5ce to ! faunas1 ow+ to ! rapidity ) :i* ! deposits 7 accumulat$4 ,x is by no means c]ta9 because ! "w has n be5 done t x _c be done1 & ! exp]i5ce obta9$ f a /udy ( o!r /rata 9 :i* subdivisions h be5 e/abli%$ by ref]5ce to ! fauna w\ld lead "o to suppose t ! non-e/abli%m5t ( subdivisions ( ! ,c>bonif]\s /rata is due to our want ( k r ?an to _! non-exi/5ce4 ,! e/abli%m5t ( a classification on palontological l9es by no means does away ) ! necessity = local classifications on a li?ological basis1 & x has already be5 rem>k$ t important results w foll[ f a comp>ison ( ! classifications ( s$im5ts f\nd$ on ! two l9es1 results :i* h hi!rto l>gely escap$ our att5tion ow+ to ! exi/5ce ( a cumbr\s classification atta9$ by ! application sometimes ( "o me?od1 at o!r times ( ! alt]native "o4 ,,*apt] ,,vii4 ,,simulation ,,( ,,/ructures4 ,al?\gh x is easy to give an acc\nt ( ! /ructures :i* are ( importance to ! /ud5t ( ! /ratifi$ rocks1 actual obs]vation ( ^! /ructures is frequ5tly att5d$ ) difficulties ow+ to ! close imitation ( "o /ructure by ano!r1 & ! pa/ hi/ory ( ! sci5ce %[s t errone\s conclusions h be5 rea*$ aga9 & aga9 on acc\nt ( ! incorrect int]pretation ( /ructures4 ,simulation ( organisms has frequ5tly be5 ! cause ( error4 ,inorganic sub/ances take on ! =m ( organisms ) v>i\s degrees ( clos5ess4 ,! d5dritic m>k+s produc$ by effloresc5ces ( oxide ( manganese are famili> to all1 & z ! "n implies1 !y simulate1 to "s ext5t1 plant rema9s4 ,m complex *emical *anges h result$ 9 ! production ( rock-masses 9 :i*1 n ! outw>d =m alone b1 ! int]nal /ructure ( organisms is reproduc$ ) m or less approa* to fidelity1 z ! rocks :i* conta9 ! suppos$ organisms describ$ z ,eozoon bohemicum1 ,e4 bav>icum1 &1 we may add1 ,e4 canad5se4 ,me*anical *anges 9 rocks subsequ5t to _! =mation may also cause ! simulation ( organisms by inorganic sub/ances4 ,pr(4 ,sollas has giv5 reasons = consid]+ ! /ructure describ$ z ,oldhamia to be inorganic1 & 9 ! ,c>bonif]\s ,s&/ones ( ,little ,hav51 ,pembroke%ire1 e /age 9 ! =mation ( tubul> bodies resembl+ worm-tubes1 z ! result ( complex fold+ ( ! /rata1 may be obs]v$1 :il/ 9 o!r cases we f9d imitation ( worm-tracks1 z has be5 obs]v$ be=e4 ,x is :5 "o inorganic /ructure is simulat$ by ano!r t ! /ratigraphical geologi/ is mo/ likely to be l$ a/ray1 & accord+ly x is wor? not+ "s cases :]e ?is has occurr$1 z a w>n+1 = x mu/ n be suppos$ t ! cases "h not$ are ! only ones :i* are likely to occur4 ,x has be5 se5 t ! exi/5ce ( b$d+-planes is ( prime importance to ! geologi/1 & _! detection is a matt] ( supreme mom5t4 ,"u ord9>y circum/ances !re is no great difficulty 9 di/+ui%+ b$d+-planes f o!r planes1 b ! importance ( discov]+ !m is (t5 greate/ :5 ! difficulty is mo/ pron\nc$4 ,9 rocks :i* h und]gone no great am\nt ( di/urbance ! planes ( /ratification are (t5 m>k$ by _! regul> p>allelism1 ! sep>ation ( lay]s hav+ diff]5t li?ological *>act]s by ^! planes1 ! arrangem5t ( ! long] axes ( pebbles p>allel to !m1 & ! occurr5ce ( fossils & also ( ra9-pr9ts1 ripple-m>ks & o!r /ructures produc$ dur+ deposition1 ^u ! surfaces ( ! /rata1 b none ( ^! appe>ances is necess>ily conclusive1 especially 9 areas :]e ! rocks h be5 subject$ to orog5ic movem5ts4 ,9 regul>ly-jo9t$ rocks1 jo9t+ may well be mi/ak5 = b$d+1 & !re is (t5 great difficulty 9 discrim9at+ betwe5 b$d+ & cleavage1 especially :5 ! exposures ( rock are ( small ext5t4 ,fossils may be dragg$ out along planes at an angle to ! true b$d+1 pebbles w be compress$ by cleavage s t _! long] axes d n rema9 p>allel to ! b$d+-planes b n[ lie p>allel to ! sup]9duc$ planes ( cleavage1 & a /ructure closely resembl+ 'ripple-m>k' may be produc$ on planes o!r ?an ^? ( orig9al b$d+1 z ! result ( puck]+4 ,! alt]nation ( rocks hav+ diff]5t li?ological *>act]s may also be mislead+4 ,intrusion ( dykes along cleavage-planes1 foll[$ by decomposition ( ! dyke-rock caus+ x to resemble a s$im5t1 & =mation ( m9]al ve9s along ! same planes1 may give rise to an app>5t succession ( rocks ( diff]5t li?ological *>act]s :i* c\ld easily mislead an obs]v] & cause him to mi/ake ! cleavage-planes = planes ( /ratification4 ,9 rocks :i* h und]gone great lat]al pressure1 ! b$s ( diff]5t li?ological "* may be fold$ 9 su* a way z to give v errone\s ideas ( ! true dip ( ! rock on a l>ge scale4 ,9 ,fig4 #c ! dip ( ! rocks 9 a small exposure might appe> to be 9 ! direction indicat$ by ! unfea!r$ arr[1 :il/ ! true dip ( ! /rata z a :ole1 leav+ ! m9or fold+s out ( acc\nt1 is 9 ! direction ( ! fea!r$ arr[1 at ! incl9ation repres5t$ by ! dott$ l9e4 ,! m9or folds 9 a case l t repres5t$ may ext5d upw>ds = scores or ev5 hundr$s ( feet1 s t an error z to ! direction & am\nt ( dip may be made1 ev5 if ! obs]v] faces a cliff ( consid]able height4 ,illu/ration3 ,fig4 #c4 ,false-b$d+ on a l>ge scale may be a cause ( error4 ,9 ! ,p5ri? ,s&/one ( ,cumb]l&1 ! planes ( deposition are (t5 f\nd dipp+ 9 "o direction 9 a l>ge qu>ry1 b inspection ( a wid] area %[s t ?is is n ! true dip ( ! b$s z a :ole1 b m]ely a local dip due to deposition on a slope1 & any "o attempt+ to calculate ! total ?ickness ( ! b$s by ref]5ce to ^! divisional planes might be s]i\sly l$ a/ray4 ,a ref]5ce to ,fig4 #d w expla9 ?is4 ,! l9es ,,aa1 ,,bb are ! true b$d+-planes cut across 9 ! section1 :il/ ! l9es slop+ to ! "r f xx are only l9es ( false-b$d+ on a l>ge scale4 ,an exagg]at$ e/imate ( ! ?ickness ( ! deposit w\ld be made by measur+ ! ?ickness ( ea* ( ^! /ratula f ,a to ,a & add+ ^! ?icknesses toge!r1 :]eas ! actual ?ickness ( ! middle b$ is ! di/ance betwe5 ,a & ,b or ,a & ,b4 ,illu/ration3 ,fig4 #d4 ,:5 rocks h be5 affect$ by ?ru/-planes1 ! simulation ( b$d+ may be c>ri$ out to a v full ext5t4 ,n only d ! major ?ru/-planes resemble b$d+-planes b ! m9or ?ru/s produce an appe>ance ( divisional planes sep>at+ /ratula or lam91 & a close approximation to false-b$d+ is ! result4 ,to ?is /ructure ,pr(4 ,bonney has giv5 ! "n 'pseudo-/romatism#ag4' ,x may be develop$ 9 rocks ( all k9ds1 :e!r possess+ orig9al planes ( /ratification or n1 & z a result ( its exi/5ce ! geologi/ may be s]i\sly misl$1 n m]ely by mi/ak+ ! direction ( ! /rata1 b also ! nature ( ! rock1 = we may f9d x produc$ 9 an un/ratifi$ glacial till1 & 9 a massive igne\s rock1 & 9 ea* case ! result+ rock w resemble a s$im5t>y deposit1 & ( c\rse ! obs]v] may be confirm$ 9 8 errone\s op9ion by ! =mation ( app>5t fossils1 ripple-m>ks or o!r objects :i* he might expect to discov] 9 s$im5ts4 ,z illu/rative examples1 ref]5ce may be made to a numb] ( s*i/ose rocks1 9 :i* ! planes ( discont9uity 7:i* are 9 tru? planes ( foliation7 h be5 tak5 = b$d+-planes & ! rocks claim$ z s$im5t>y ?\gh !y are 9 reality igne\s2 = in/ance _m ( ! rocks ( ! ,laur5tian ( ,canada1 ( ! ,hebridean ( ! ,nor? ,we/ ,highl&s1 & "s ( ! anci5t rocks ( ,anglesey4 ,footnote #ag3 ,bonney1 ,t4 ,g41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlii4 ,proc4 p4 #fe4 ,a foliat$ /ructure may1 z is n[ well kn[n1 be simulat$ by a /ructure develop$ 9 a rock prior to its consolidation4 ,! simil>ity ( fl[ /ructure ( "s lavas to ! foliat$ /ructure ( a s*i/ 0 long ago po9t$ out by ,d>w9 & ,scrope1 & rec5t "w has prov$ t p>allel /ructure due to diff]5tial movem5t prior to consolidation may be develop$ 9 plutonic rocks1 z %[n by ,lieut4-,g5]al ,mc,mahon 9 ! ,himalayan granites1 & by ,lawson among/ ! plutonic rocks ( ! ,ra9y ,lake ,region2 & z ! foliat$ /ructure may be mi/ak5 = orig9al /ratification ! same may occur1 & has occurr$1 :5 deal+ ) ?is fl[-/ructure4 ,?is is n ! place to discuss ! tru? ( ! old !ory ( progressive metamorphism1 9 :i* x 0 ma9ta9$ t a gradual passage c\ld be trac$ betwe5 ord9>y s$im5ts & plutonic rocks1 b x may be po9t$ out t mu* ( ! evid5ce :i* 0 reli$ ^u to prove ! !ory 0 fallaci\s & due to ! confusion ( ! p>allel /ructure set up 9 plutonic rocks prior to1 or subsequ5t to1 consolidation1 ) orig9al /ratification4 ,rec5t /udy ( metamorphic rocks has prov$ t ! p>allel /ructures develop$ 9 ! rocks ( an area :i* has und]gone metamorphism may be produc$ by ?ree di/9ct processes2 !y may be orig9al planes ( deposition1 or =m$ 9 a solid rock subsequ5tly to its =mation1 or 9 an igne\s rock be=e its consolidation1 & al?\gh x is sometimes possible to sep>ate ! /ructures produc$ by ^! processes1 ?is is n always ! case#ah4 ,:5 a plutonic rock conta9s l>ge ph5ocry/s & an eye-/ructure is develop$ 9 x1 x may simulate a conglom]ate1 ! r\nd$ ph5ocry/s be+ tak5 = pebbles#ai4 ,/ill clos] simulation ( an epicla/ic conglom]ate may be produc$ 9 o!r ways & w be ref]r$ to imm$iately4 ,footnote #ah3 ,x mu/ be notic$ t ! rock 9 :i* p>allel /ructure is produc$ be=e consolidation1 if x und]goes no fur!r *ange1 ?\gh (t5 associat$ ) metamorphic rocks1 is n itself metamorphic4 ,! t]m gneiss appli$ to ^! rocks is a misnom]1 unless ! t]m be us$ ev5 m vaguely ?an x is at pres5t4 ,footnote #ai3 ,see ,lehmann1 ,unt]su*ung5 b] die ,ent/ehung d] ,altkry/all9is*5 ,s*ief]ge/e9e mit besond]] ,bezugnahme auf das ,s*sis*e ,granulitgebirge1 ,plate ,,xi4 fig4 #a4 ,we h already se5 t ! exi/5ce ( uncon=mities has be5 utilis$ 9 ! dem>cation ( l>ge divisions ( /rata 9 v>i\s regions1 & :e!r !y be utilis$ 9 ?is mann] or n1 _! detection is a matt] ( importance to ! /ratigraphical geologi/1 z !y af=d in=mation conc]n+ ! occurr5ce ( great physical *anges dur+ _! production4 ,^! uncon=mities may also be closely simulat$ by /ructures produc$ 9 v diff]5t mann]4 ,! occurr5ce ( an uncon=mity implies ! d5udation ( "o set ( b$s be=e ! deposition ( ano!r set ^u !m1 & accord+ly ! d5ud$ edges ( ! l[] set w some:]e abut aga9/ ! l[] surface ( ! l[e/ deposit or deposits ( ! ov]ly+ set#bj4 ,! exi/5ce ( an uncon=mity may (t5 be detect$ 9 section1 b :5 ! uncon=mity is ^u a l>ge scale ?is may n be possible1 b x w be discov]$ by mapp+ ! /rata & w be app>5t on a map ow+ to ! deposits ( ! l[] set ( b$s abutt+ aga9/ ! o!rs4 ,?is is well se5 :]e ! ,p]mian rocks ( ,durham1 ,york%ire1 & ,nott+ham%ire re/ ^u diff]5t memb]s ( ! und]ly+ ,c>bonif]\s s]ies1 & w be notic$ on any good geological map ( ,engl&4 ,b a simil> effect may be caus$ by a fault1 s t m]e inspection ( a map or ev5 ( ! /rata 9 ! field & discov]y ( "o set ( b$s end+ (f aga9/ ano!r does n prove uncon=mity4 ,:5 ! fault is a normal "o1 ) l[ hade 7t is1 hav+ a fissure approa*+ ! v]tical position71 ! outcrop ( ! fault-fissure w approximate to a /raight l9e if ! fault has a /raight c\rse1 ev5 if ! gr\nd be v unev51 :]eas1 if ! plane ( uncon=mity has n be5 tilt$ to a high angle f its orig9al horizontal position1 x w crop out 9 a s9u\s mann] across unev5 gr\nd1 9 a way simil> to t ( b$s :i* are ne>ly horizontal1 s t ?\gh ! g5]al tr5d ( ! outcrop ( ! plane ( uncon=mity may be fairly /raight1 its deviation f a /raight l9e w be frequ5t & m>k$1 z se5 9 ! case ( ! ,p]mian uncon=mity above ref]r$ to4 ,b if ! uncon=mable junction has be5 highly incl9$ its outcrop w resemble t ( a normal fault1 or if ! fault be a ?ru/-plane ) high hade1 ! outcrop ( ?is w resemble t ( an uncon=mable junction :i* has n be5 greatly tilt$ f its orig9al horizontal position4 ,9 ^! cases we require m evid5ce be=e we c decide :e!r we are deal+ ) an uncon=mable junction or a fault$ "o4 ,footnote #bj3 ,an uncon=mity may be simulat$ or an actual uncon=mity r5d]$ app>5tly m important1 z ! result ( und]gr\nd solution ( ! und]ly+ /rata subsequ5tly to ! deposition ( ! upp] set ^u !m1 & any insoluble mat]ials 9 ! und]ly+ /rata may be left z an app>5t pebble-b$ at ! base ( ! upp] b$s4 ,?is is se5 at ! junction ( ! ,t]ti>y b$s ) ! *alk ne> ,london4 ,subt]ranean wat] has dissolv$ ! upp] "p ( ! *alk1 increas+ ! uncon=mity :i* naturally exi/s betwe5 *alk & ,t]ti>y b$s1 & ! insoluble fl9t ( ! dissolv$ *alk is left z a lay] ( 'gre5-coat$ fl9t' at ! base ( ! ,t]ti>y deposits4 ,! l[e/ deposits ( ! new] set ( /rata ly+ above an uncon=mity h probably be5 laid d[n 9 wat] ne> ! %ore-l9e4 ,z ! uncon=mity1 if l>ge1 implies elevation above ! sea-level1 ! deposits fir/ =m$ aft] ?is elevation has ceas$1 & depression comm5c$1 w necess>ily be littoral 9 "* & possibly ( bea*-=mation1 & accord+ly we (t5 f9d t an uncon=mity is m>k$ by ! exi/5ce ( an epicla/ic conglom]ate imm$iately above ! plane ( uncon=mity &1 al?\gh ?is ne$ n be cont9u\s1 x is usually f\nd some:]e along ! l9e ( junction4 ,! conglom]atic base ( ! ,l[e/ ,c>bonif]\s /rata :5 !y repose ^u ! upturn$ edges ( ! ,l[] ,palozoic rocks ( ! dales ( ,we/ ,york%ire is well kn[n1 & may be cit$ z an example4 ,! association ( conglom]ates ) uncon=mities is inde$ s frequ5t t its possible occurr5ce w always be suspect$ & s\ght by ! geologi/4 ,un=tunately ! result ( rec5t obs]vation is to %[ t along ?ru/-planes ( :i* ! outcrop simulates ^? ( uncon=mable junctions1 ! difficulty ( discrim9ation may be increas$ by ! exi/5ce ( catacla/ic rocks :i* be> a close resemblance to epicla/ic conglom]ates1 & :i* may be & h be5 /yl$ conglom]ates4 ,x is well kn[n t fragm5ts ( ! adjo9+ rocks are knock$ into a fault-fissure dur+ ! occurr5ce ( ! movem5ts :i* cause ! fault1 to con/itute a fault-breccia1 & z ! result ( ! abrasion ( ^! fragm5ts by *emical or me*anical ag5cy1 ! angul> fragm5ts may become r\nd$ & conv]t$ into r\nd$ pebble-l bodies1 :5 ! rock is *ang$ into a fault-conglom]ate4 ,fig4 #e1 f a photograph k9dly suppli$ by ,pr(4 ,w4 ,w4 ,watts1 %[s a /age 9 ! =mation ( a conglom]ate ( ?is nature f a fault-breccia2 ! fragm5t on ! "r rema9s angul>1 :il/ ^? on ! left h become mu* m r\nd$4 ,! illu/ration is f a case describ$ by ,mr ,lamplugh occurr+ 9 ! slaty rocks ( ! ,isle ( ,man1 & ,mr ,lamplugh's pap]#ba furni%es ! read] ) ref]5ces to o!r examples ( ! production ( simil> rocks4 ,no g5]al rule c be laid d[n = di/+ui%+ ! true f ! app>5t uncon=mity1 = ! att5dant ph5om5a w diff] 9 ea* case2 b if a fault-conglom]ate %\ld be suspect$1 ! obs]v] %\ld try to asc]ta9 :e!r fragm5ts ( a new] rock are imb$d$ 9 an old] "o1 :i* sometimes occurs2 he %\ld note ! exi/5ce ( ext5sive slick5sid+ along ! plane ( junction & along planes ( fault+1 ?\gh ! exi/5ce ( ^!1 imply+ z x does ! occurr5ce ( diff]5tial movem5t along ! plane1 does n prove t ! movem5t 0 necess>ily great1 or t x did n take place along a plane ( orig9al uncon=mity2 above all1 he %\ld look = /ructures su* z mylonitic /ructure1 pseudo-/romatism1 developm5t ( new m9]als1 cru%+ out & /ret*+ ( fossils & fragm5ts &1 9 %ort1 = any /ructure :i* is famili> to him z a result ( orog5ic movem5ts4 ,footnote #ba3 ,lamplugh1 ,g4 ,w41 ,on ! ,cru%-,conglom]ates ( ! ,isle ( ,man1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,li4 p4 #efc4 ,illu/ration3 ,fig4 #e4 ,! effects ( ?ru/+ n only give rise to appe>ances sugge/ive ( uncon=mity1 b naturally also to a simulation ( ov]lap4 ,! ?ru/-planes are (t5 p>allel to orig9al b$d+-planes = "s di/ance1 b mu/ cut across !m soon] or lat]1 produc+ l5ticul> masses :i* might be suppos$ to be due to ! ?9n+ out ( b$s z ! result ( cessation ( deposition 9 a lat]al direction4 ,att5tion has already be5 direct$ to ! deceptive appe>ance ( great ?ickness ( /rata :i* is due to repetition ( "o /ratum or set ( /rata by a s]ies ( ?ru/-planes1 s t !re is no actual inv]sion ( any "p ( a b$4 ,:5 masses ( lime/one are affect$ 9 ?is way1 ! ?ru/-planes may become seal$ up1 z ! result ( *emical *ange1 & a compact irregul> mass ( lime/one devoid ( any def9ite divisional planes may be ! consequ5ce1 & b$s ( grit sometimes exhibit ! same feature to "s ext5t4 ,en\gh has be5 said to %[ t simulation ( "o /ructure by ano!r has frequ5tly occurr$ 9 rocks 9 s m>k$ a degree z to r5d] mi/akes easy2 & t ^! examples ( 'mimicry' 9 ! inorganic _w are p>ticul>ly frequ5t 9 rocks :i* h be5 subject$ to great orog5ic movem5ts4 ,! /ud5t w d well to acqua9t himself ) ! macroscopic & microscopic /ructures :i* may be tak5 z *>act]i/ic ( ! rocks :i* h be5 ?us affect$1 "s ( :i* c usually be detect$ ) ease1 & :5 he discov]s !m he may suspect t _m ph5om5a :i* appe> explicable 9 "o way 7 9 reality produc$ 9 a diff]5t "o1 = x is frequ5tly v true ( a region 9 :i* ! rocks h be5 viol5tly squeez$1 /ret*$ & brok5 t '?+s are n :at !y seem4' ,,*apt] ,,viii4 ,,geological ,,maps ,,& ,,sections4 ,! writ] does n propose to give an acc\nt ( ! intricacies ( geological mapp+1 = _! "r consid]ation requires a sep>ate treatise#bb2 all he desires is to call att5tion to "s ( ! uses ( geological maps z a means ( convey+ in=mation4 ,a geological map may be look$ ^u z an attempt to express z f> z possible 9 two dim5sions ph5om5a :i* possess ?ree dim5sions2 ?is c be done to "s ext5t on ! actual surface ( ! map1 by conv5tional signs1 /ill m fully1 by supplem5t+ ! map ) sections2 b be/ ( all by a geological model1 :i* is cut across 9 v>i\s directions 9 ord] to %[ ! und]gr\nd /ructure z well z t ( ! surface4 ,footnote #bb3 ,! /ud5t is recomm5d$ to consult 9 p>ticul>1 ,app5dix ,i4 ,on ,geological ,survey+ 9 ,! ,/ud5t's ,manual ( ,geology1 by ,j4 ,b4 ,jukes 7,?ird ,edition1 ,edit$ by ,a4 ,geikie71 p4 #gdg1 & ,outl9es ( ,field ,geology1 by ,sir ,a4 ,geikie 7,macmillan & ,co474 ,! ord9>y geological map is "o :i* %[s ! outcrop ( ! /rata1 subdivid$ accord+ to age1 z !y w\ld be se5 ^u ! surface ( ! e>? aft] /ripp+ (f ! sup]ficial accumulations1 & x is to be fe>$ t ! t]m 'geological map' is associat$ 9 ! m9ds ( mo/ /ud5ts ) a map ( ?is "* & ( no o!r4 ,nev]!less1 a great _m mo/ important obs]vations o!r ?an ^? connect$ ) ! ord] ( succession ( ! /rata are capable ( repres5tation ^u a geological map1 & ! possession ( a l>ge numb] ( maps ( any area ^u ! geology ( :i* a p]son is engag$--ea* map to be us$ = record+ obs]vations ( a p>ticul> k9d--w save mu* writ+ 9 note-books &1 :at is ( m importance1 w all[ him to comp>e obs]vations :i* h be5 made at diff]5t times at a glance1 in/ead ( caus+ him to se>* ?r\gh a s]ies ( note-books4 ,/ill1 h[ev] well furni%$ ) maps1 ! geologi/ w f9d a note-book ess5tial#bc4 ,footnote #bc3 ,z a result ( "s exp]i5ce1 ! writ] recomm5ds e /ud5t to acquire "s skill 9 ! use ( ! p5cil1 & if to su* a degree t he c comb9e arti/ic effect ) accuracy1 s mu* ! bett]4 ,an acqua9tance ) photography is invaluable3 (t5 ! possession ( a cam]a w\ld enable a section to be record$1 :i* is o!rwise lo/ to sci5ce4 ,! e>lie/ geological maps repres5t$ ! v>iations 9 ! surface soils1 or at mo/ ! g5]al li?ological *>act]s ( ! rocks :i* by _! decay furni%$ ! mat]ials = ! soils4 ,we h se5 t ! fir/ *ronological map 0 due to ,william ,smi?1 & mo/ subsequ5t ,engli% geological maps h be5 bas$ ^u 8 map ( ! /rata ( ,engl& & ,wales4 ,! ord] ( succession ( ! /rata is repres5t$ 9 ^! maps to "s ext5t by ! use ( arr[s to indicate ! direction ( dip ( ! /rata1 ?\gh ?is is n an un]r+ guide :]e /rata are rev]s$1 & accord+ly ! addition ( a leg5d at ! side ( ! map may be look$ ^u z ess5tial to ! correct und]/&+ ( ! map itself4 ,! leg5d is usually 9 ! =m ( a section ( a column1 ! /rata be+ arrang$ 9 "r ord]1 ! olde/ at ! base & ! newe/ at ! summit1 ! col\rs by :i* ! /rata are indicat$ be+ simil> to ^? plac$ ^u ! map4 ,o!r in=mation besides ! m]e ord] ( succession ( ! /rata may appe> 9 ! leg5d2 ?us _! relative & actual ?icknesses c be indicat$ if ! column is drawn to "s def9ite scale1 & a brief description ( ! li?ological *>act]s ( ! rocks may well be app5d$ to ! side ( ! column4 ,on ! actual maps x is cu/om>y to exhibit ! outcrop ( ! junctions ( all igne\s rocks z well z ( ! s$im5t>y ones3 ! nature ( ! metamorphism :i* s$im5t>y rocks h und]gone at ! contact ) igne\s ones may be & (t5 is indicat$ by suitable signs2 ! position ( faults is %[n1 & (t5 also t ( metallif]\s ve9s1 ! nature ( ! ore 9 ! latt] be+ fur!r indicat$ 9 "s suitable mann]1 z by giv+ ! recognis$ symbol = ! metal2 & 9 _m maps an attempt is made to %[ ! v>iations 9 dip & /rike ( ! cleavage-planes4 ,! ,geological ,survey ( ! ,unit$ ,k+dom publi%es two sets ( maps1 "o %[+ ! 'solid geology' & ! o!r ! 'sup]ficial geology4' ,x is easi] to und]/& ^! t]ms ?an to def9e !m1 = 9 ,brita9 !re is a %>p l9e betwe5 ! two ev]y:]e except ne> ,crom]4 ,! maps %[+ ! sup]ficial geology repres5t gravels1 glacial drifts & o!r incoh]5t accumulations ( geologically rec5t orig91 :i* to a great] or less ext5t mask ! /rata bel[ :i* are usually compos$ ( m or less solidifi$ mat]ial4 ,! maps %[+ ! solid geology display ! outcrops ( ^! /rata1 ?\gh x is usual to ins]t alluvium ^u ^! maps1 z x is (t5 impossible to trace ! junction-l9es ( ! /rata bel[ x4 ,att5tion has already be5 direct$ to ! fact t ^! maps ( solid geology1 ?\gh *ronological1 t is1 hav+ ! /rata repres5t$ accord+ to age1 are f\nd$ l>gely ^u li?ological diff]5ces1 r ?an ^u includ$ organisms2 & x has be5 /at$ t = !oretical purposes two sets ( *ronological maps1 "o f\nd$ ^u li?ological diff]5ces1 ! o!r ^u diff]5ce ( fossil organisms1 w\ld be extremely valuable4 ,o!r ph5om5a are (t5 be/ repres5t$ ^u sep>ate maps1 = if all obs]vations are cr[d$ ^u "o map ! result w be v confus+4 ,special glacial maps %[+ ! cont\r ( ! c\ntry1 ) ! portions betwe5 ! cont\r l9es col\r$ diff]5tly accord+ to altitude1 say ! c\ntry betwe5 sea-level & #ejj feet light gre51 t betwe5 #ejj & #ajjj d>k gre51 t betwe5 #ajjj & #aejj light br[n & s on1 exhibit+ ! direction ( all obs]v$ glacial /riae1 ! di/ribution ( b\ld]s s f> z x is possible1 & any o!r glacial ph5om5a :i* c be not$ ^u ! map1 w be valuable to ! /ud5t ( glaciation#bd4 ,footnote #bd3 ,= examples see ,tiddeman1 ,r4 ,h41 ,evid5ce = ! ,ice-,%eet 9 ,nor? ,lanca%ire & ! adjac5t p>ts ( ,york%ire & ,we/morl&1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxviii4 pl4 ,,xxx41 & ,good*ild1 ,j4 ,g41 ,glacial ,ph5om5a ( ! ,ed5 ,valley c41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxi4 pl4 ,,ii42 & = a map ( di/ribution ( b\ld]s1 ,w>d1 ,j4 ,c41 ,geology ( ! ,nor!rn ,"p ( ! ,engli% ,lake ,di/rict 7,mem4 ,geol4 ,survey71 pl4 ,,iv4 ,v>i\s /ructural features may be well display$ on sep>ate maps4 ,! tr5d ( ! axes ( folds w be useful1 & may be accompani$ by o!r in=mation ( cognate "*#be2 maps ( ! di/ribution ( jo9t planes may be giv5 9 comb9ation ) ^? %[+ ! fold+ ( ! /rata if x be desir$ to exhibit ! relation%ip betwe5 ^!2 or ) ! physical features ( ! c\ntry1 if ! dep5d5ce ( physical features ^u jo9t /ructure be "u consid]ation#bf4 ,mu* in=mation conc]n+ cleavage may be acquir$ f a map %[+ anticl9al & syncl9al axes ( cleavage#bg1 or ! actual /rike ( ! cleavage ov] diff]5t p>ts ( a map may be repres5t$1 & its relation%ip to ! geological /ructure ( ! di/rict exhibit$#bh4 ,footnote #be3 ,see ,b]tr&1 ,m41 ,sur le ,raccordem5t des ,bass9s ,h\ill]s du nord de la ,france et du sud de l',anglet]re1 ,annales des ,m9es1 ,jan4 #ahic1 ,plate #a4 ,footnote #bf3 ,see ,daubre1 ,a41 tudes ,syn?tiques de ,gologie ,exprim5tale1 #are ,p>tie1 ,plates ,,iii4-,,vi41 = an example ( ! latt]1 :i* is also int]e/+ z %[+ ! utility ( a map on transp>5t pap] sup]-pos$ on ano!r1 :5 illu/rat+ ! connexion betwe5 two sets ( /ructures4 ,footnote #bg3 ,w>d1 ,j4 ,c41 ,geology ( ! ,nor!rn ,"p ( ! ,engli% ,lake ,di/rict1 ,plate ,,ix4 ,footnote #bh3 ,h>k]1 ,alfr$1 ,! ,bala ,volcanic ,s]ies ( ,ca]n>von%ire 7,s$gwick ,essay = #ahhh71 ,fig4 #e4 ,maps exhibit+ *anges 9 physical geography app]ta9 to ! geologi/ z well z to ! geograph]4 ,! position ( anci5t bea*es1 =m] lakes1 repres5tation ( ! *anges 9 ! c\rses ( riv]s & k9dr$ ph5om5a may be %[n ^u maps1 & w prove useful#bi4 ,footnote #bi3 ,= examples ( maps ( ?is k9d1 see ,kj]ulf1 ,?41 ,die ,geologie des sdli*5 und mittl]5 ,norweg54 ,a p]usal ( ! maps to :i* ref]5ce has be5 made above w give ! /ud5t "s notion ( ! ext5t to :i* maps may be utilis$ to repres5t geological /ructures1 & may sugge/ o!r me?ods by :i* !y may be utilis$4 ,a geological section is usually drawn 9 ord] to exhibit ! lie ( ! rocks1 z x w\ld be se5 if a v]tical cutt+ 7 made 9 t "p ( ! e>?'s cru/ :i* is "u consid]ation4 ,! "* ( ! section w dep5d ^u circum/ances4 ,! ,geological ,survey ( ,great ,brita9 issues two k9ds ( sections :i* are usually spok5 ( z v]tical sections & horizontal sections1 ?\gh ea* is 9 tru? a v]tical section2 b :]eas 9 ! =m] ! horizontal di/ance repres5t$ is small z comp>$ ) ! ?ickness ( ! /rata1 9 ! latt] ! rocks ( a consid]able horizontal ext5t ( c\ntry are exhibit$ 9 ! section1 & ! section is n c>ri$ d[n to a great dep? bel[ ! e>?'s surface4 ,!re is no ess5tial diff]5ce betwe5 ! two k9ds ( section1 & (t5 sections are drawn :i* _c be def9itely class$ z belong+ to ei!r k9d1 b 9 extreme cases ! v]tical section is a repres5tation ( ! ord] ( succession z x w\ld appe> if ! rocks 7 horizontal1 no matt] h[ di/urb$ !y may be 9 reality2 :]eas ! horizontal section repres5ts ! /rata z !y actually occur1 ) all ! folds & faults by :i* !y are affect$4 ,! accompany+ figure 7,fig4 #f7 repres5ts a horizontal section on ! left side ( ! figure ) a v]tical section ( ! same rocks on ! "r side4 ,illu/ration3 ,fig4 #f4 ,v]tical sections are extremely useful :5 x is desirable to comp>e v>iations 9 ! /rata ov] wide ext5ts ( c\ntry3 ?is c be done by draw+ a s]ies ( columns ( ! /rata1 ea* %[+ 9 v]tical section ! li?ological *>act]s & ?icknesses ( ! /rata 9 "o place1 :il/ ! relation%ip betwe5 ! /rata ( two diff]5t places may be indicat$ by jo9+ ! b$s ( ! same age by dott$ l9es z %[n 9 ,fig4 #gcj4 ,illu/ration3 ,fig4 #g4 ,footnote #cj3 ,x is useful to adopt conv5tional symbols = ! repres5tation ( /rata ( diff]5t li?ological *>act]s1 & s f> z possible to adh]e to ! same k9d ( symbol = any "o k9d ( deposit4 ,^? :i* are g5]ally 9 use1 are r\gh pictorial repres5tations ( ! *>act]s ( ! deposits1 z %[n 9 ,fig4 #g4 ,! conglom]ate is indicat$ by circul> m>ks repres5t+ cross-sections ( ! pebbles1 a breccia by triangul> m>ks signify+ t ! fragm5ts are angul> & n r\nd$2 a s&/one is indicat$ by dots to repres5t ! gra9s ( s&2 a mud1 clay or %ale by cont9u\s or brok5 horizontal l9es1 :i* reproduce ! appe>ance ( ! planes ( lam9ation s frequ5t 9 b$s ( ?is composition2 a lime/one is usually m>k$ by ! use ( regul> horizontal l9es illu/rat+ ! pron\nc$ b$d+1 ) v]tical l9es at int]vals to repres5t ! regul> jo9t+ :i* occurs 9 s _m lime/ones3 ! nature ( ! b$d+ may be fur!r %[n by draw+ ! l9es comp>atively f> ap>t :5 ! lime/one is a ?ick-b$d$ "o1 ne>] toge!r :5 x is ?9-b$d$4 ,igne\s rocks are repres5t$ by crosses or irregul> ,v-%ap$ m>ks1 illu/rat+ ! abs5ce ( /ratification & pres5ce ( jo9ts4 ,volcanic a%es are sometimes repres5t$ by dots1 at o!r times by signs some:at simil> to ^? :i* are us$ = true igne\s rocks4 ,s$im5t>y rocks :i* are compos$ ( m ?an "o k9d ( mat]ial may be fur!r %[n by a comb9ation ( two symbols1 ?us ! exi/5ce ( a s&y clay may be %[n by means ( a comb9ation ( horizontal l9es & dots1 & s ) o!r comb9ations4 ,! practical geologi/ %\ld become accu/om$ to ! use ( ^! symbols 9 8 note-book2 if us$1 !y w save mu* writ+4 ,^! symbols are us$ 9 "s ( ! lat] illu/rations to ?is book4 ,! horizontal section is "o :i* is 9 con/ant use by ! practical geologi/3 ! results ( ! fir/ trav]se ( a di/rict may be jott$ d[n 9 8 note-book 9 ! =m ( a horizontal section 7) accompany+ notes71 & ! writt5 memoir on ! geology ( any di/rict compos$ l>gely ( /ratifi$ rocks w almo/ c]ta9ly require illu/ration by means ( ^! sections4 ,p]haps no?+ m cle>ly m>ks ! c>eful obs]v] ?an ! nature ( ! sections :i* he makes1 & geological lit]ature is too frequ5tly m>r$ by ! publication ( slov5ly sections4 ,a badly drawn section n only (f5ds ! eye1 x may & frequ5tly does convey inaccurate in=mation4 ,illu/ration3 ,fig4 #h4 ,9 ! above figure 7,fig4 #h7 tak5 f ,sir ,h5ry de la ,be*e's ,sections & ,views ,illu/rative ( ,geological ,phnom5a1 ,plate ,,ii41 ! l[] draw+ repres5ts a section drawn to true scale1 :ile t above %[s "o :i* is exagg]at$4 ,! /ud5t :o saw ?is w\ld inf] t ! upp]mo/ b$s on ! left side ( ! upp] section re/$ uncon=mably ^u ! dott$ b$s b5ea?1 & once abutt$ aga9/ !m 9 t portion ( ! figure :]e ! b$s h be5 remov$ by d5udation 9 ! deep valley1 :]eas an exam9ation ( ! section drawn to true scale %[s t ! uncon=mity does n exi/ 7al?\gh !re is "o at ! base ( ! deposits m>k$ by dots71 & t !re is room = ! high] deposits to pass above ^? m>k$ by dots at ! place :]e ! =m] h be5 remov$ by d5udation4 ,:5ev] possible1 horizontal sections %\ld be drawn to true scale1 ! v]tical heights be+ on ! same scale z ! horizontal di/ances4 ,sections :i* are s drawn repres5t ! nature ( ! surface ( ! c\ntry z well z ! relation%ip ( ! /rata1 & (t5 illu/rate 9 a m>k$ degree ! influ5ce :i* ! "* ( ! /rata has ex]t$ ^u ! nature ( ! sup]ficial features ( a c\ntry4 ,if x be impossible to draw a section 9 :i* ! elevations & horizontal di/ances are repres5t$ ^u a true scale1 ! =m] ought to be drawn on a scale :i* is a multiple ( ! latt]2 ?us ! v]tical heights may be %[n on #b1 #c1 or #d or m times ! scale *os5 = ! horizontal di/ances2 :5 ?is is done1 x w (t5 be necess>y to %[ ! /rata ) an exagg]at$ dip1 & accord+ly ! exagg]at$ section loses "s ( its value1 ?\gh if v]tical & horizontal scales be> "s def9ite proportion x w /ill be m valuable ?an a r\gh diagram :i* is n drawn to any scale4 ,section-draw+ _c be satisfactorily accompli%$ )\t "s practice1 & ! /ud5t is /rongly advis$ to acquire ! art ( draw+ good sections2 ! writ] c ass]t z ! result ( consid]able exp]i5ce 9 ! conduct ( exam9ations ( all k9ds1 t slov5ly sections are ! rule 9 c&idates' pap]s1 & good sections v r>ely appe>4 ,/udy ( ! six-in* maps & horizontal sections 7drawn on ! same scale7 ( ! ,geological ,survey ( ! ,unit$ ,k+dom w enable ! /ud5t to famili>ise himself ) admirable sections1 & x %\ld be 8 aim to produce sections l ^!4 ,he is recomm5d$ to take "s ( ^! six-in* maps :i* %[ cont\r-l9es z well z ! disposition ( ! /rata1 & to draw sections on ! scale ( six in*es to ! mile1 v]tical & horizontal1 exhibit+ ! prop] outl9e ( ! gr\nd & ! arrangem5t ( ! /rata1 & aft]w>ds to comp>e !m ) ! publi%$ sections4 ,! sections %\ld be drawn z f> z possible at "r angles to ! g5]al /rike ( ! /rata4 ,"s datum-l9e is tak5 = ! base ( ! section 7say sea-level7 & (fsets drawn v]tically f ?is :]e ! section crosses a cont\r-l9e or record$ height4 ,! height is m>k$ on ^! (fsets2 ?us if a record$ height ( #bgjj feet 7j ov] half a mile7 occurr$ on ! l9e ( section a height ( some:at ov] ?ree in*es is m>k$ on ! (fset1 & s ) ! o!r po9ts :]e ! section crosses cont\rs or record$ heights4 ,by jo9+ ^! po9ts on ! (fsets1 giv+ ! connect+ l9es curves simil> to ^? :i* are likely to occur 9 nature1 ! g5]al "* ( ! surface ( ! gr\nd is repres5t$4 ,! geology ( ! di/rict is next %[n4 ,:]ev] a dip is m>k$ on ! map1 ! direction & am\nt ( dip is %[n by a %ort l9e on ! section1 & :]e dips are n actually se5 along ! l9e ( section1 ! dips :i* are ne>e/ to t l9e on ! map mu/ be consid]$1 & m>k$ on ! section4 ,! l9es ( junction betwe5 ! v>i\s deposits %[n by diff]5t col\rs ^u ! map are ins]t$ on ! section z %ort l9es1 ! incl9ation be+ judg$ by /udy ( ! ne>e/ dips2 faults & igne\s rocks mu/ be m>k$ (f1 & any indication ( ! hade ( ! fault or ! slope ( ! edges ( ! igne\s rock :i* ! map af=ds w be tak5 into acc\nt4 ,! section w !n appe> some:at z %[n 9 ! foll[+ figure3 ,illu/ration3 ,fig4 #i4 & suffici5t indication ( ! tr5d ( ! rocks w be obta9$ to %ew t !y =m portions ( curves :i* may !n be fill$ 9 z %[n 9 ,fig4 #aj & ! section w be complete4 ,illu/ration3 ,fig4 #aj4 ,x w be notic$ t ! small dyke ( igne\s rock on ! "r ( ! ma9 dyke is jo9$ to x l[] d[n1 ?\gh no indication ( ?is is giv5 along ! l9e ( section2 b ! requisite in=mation = ?is & evid5ce ( ! exi/5ce ( ! small dyke proce$+ f ! left-h& side ( ! ma9 "o may be obta9$ by ! /udy ( ! rocks 9 a valley on "o side or o!r ( ! l9e ( section4 ,aft] ! /ud5t has become conv]sant ) ! nature ( geological maps & sections1 & has read ,sir ,a4 ,geikie's ,outl9es ( ,field ,geology1 he %\ld on no acc\nt omit to le>n some?+ ( ! art ( mak+ geological maps1 by go+ into ! field & attempt+ to produce a map1 = ! art ( geological survey+ does n come naturally to any "o1 & "s acqua9tance ) ! me?ods ( survey+ is a necessity to ev]yone :o wi%es to make orig9al geological obs]vations1 ?\gh all _c expect to af=d ! "t & acquire ! skill necess>y = ! production ( maps vy+ ) ! detail$ maps ( ! ,gov]nm5t ,survey4 ,be=e actually attempt+ to draw l9es on a map on 8 own acc\nt1 he w d well to tramp ov] a portion ( a di/rict ) ! publi%$ geological map 9 8 h&s1 select+ a c\ntry :i* is n *>act]is$ by great intricacy ( geological /ructure1 & he c !n attempt to repres5t ! geology ( ano!r portion ( ! same di/rict )\t consult+ ! publi%$ map4 ,( all ! di/ricts ( ,brita9 ) :i* he is acqua9t$ ! writ] believes t ! bas9 ( ! riv] ,ribble1 9 ! neighb\rhood ( ! t[n ( ,settle 9 ! ,we/ ,rid+ ( ,york%ire1 is be/ adapt$ = /udy+ field geology 9 ! way sugge/$ above1 = ! ma9 geological features are m>k$ by extreme simplicity1 & ! exposures are good1 :il/ ! pres5ce ( an important fault-sy/em & ( a great uncon=mity relieve ! area f monotony4 ,anyone :o /&s on ! summit ( ,+lebor\gh or ,p5ygh5t w grasp ! ma9 features ( a portion ( ! di/rict )\t any difficulty1 = x lies b5ea? 8 feet l a geological model1 & :5 ! /ud5t has ma/]$ & mapp$ 9 ! lead+ features1 he c f9d bits ( c\ntry ) geology ( v>y+ degrees ( complexity among/ ! ,l[] ,palozoic rocks ( ! valleys :i* run d[n to ,+leton1 ,clapham1 ,au/wick & ,settle4 ,! biologi/ is suppli$ ) laboratories at home & abroad1 :]e he may /udy 8 sci5ce "u ! be/ conditions4 ,w\ld t "s munific5t p]son w\ld f\nd1 9 a di/rict l t ref]r$ to above1 a geological /ation :]e ,cambridge /ud5ts w\ld h ! means ( acquir+ a k ( field-geology "u conditions m fav\rable ?an ^? pres5t$ by ! flats ar\nd ! sluggi% ,cam6 ,,*apt] ,,ix4 ,,evid5ces ,,( ,,conditions ,,"u ,,:i* ,,/rata ,,7 ,,=m$4 ,! e/abli%m5t ( ! ord] ( succession ( ! /rata1 & ! correlation ( /rata ( diff]5t areas m]ely pave ! way = ! geologi/4 ,to write ! hi/ory ( ! e>? dur+ v>i\s geological ages1 he has to asc]ta9 ! physical & climatic conditions :i* prevail$ dur+ ! successive geological p]iods1 & to /udy ! v>i\s problems connect$ ) ! life ( ea* p]iod4 ,9 ! pres5t *apt] an attempt w be made to illu/rate ! me?ods :i* h be5 pursu$ 9 ord] to write to ! fulle/ degree :i* is compatible ) our pres5t k1 ! e>?-hi/ory ( v>i\s ages ( ! pa/4 ,9 mak+ ?is attempt1 ! physical & climatic conditions may be fir/ consid]$1 & _! consid]ation foll[$ by t ( ! *anges 9 ! faunas1 ?\gh x w frequ5tly be necess>y to ref] to "o set ( conditions z illu/rative ( ! o!r4 ,x w be assum$ "h t ! great pr9ciple ( geology1 t ! mod]n *anges ( ! e>? & its inhabitants are illu/rative ( pa/ *anges1 is rigidly true4 ,ref]5ce w be made to ?is pr9ciple 9 a lat] *apt]1 b x is suffici5t to /ate "h t ! /udy ( ! s$im5ts :i* h be5 deposit$ f ! comm5cem5t ( ,l[] ,palozoic times to ! times 9 :i* we n[ live be> ! m>ks ( hav+ be5 =m$ "u physical conditions1 :i*1 9 ! ma91 are simil> 9 k9d to ^? :i* prevail ^u "s "p ( ! surface ( ! li?osph]e at ! pres5t day4 ,"o ( ! mo/ important inf]5ces ( ! /ratigraph] relates to ! exi/5ce ( m>9e or t]re/rial conditions ov] an area at any p>ticul> "t1 & we may1 9 ! fir/ place1 consid] ! evid5ce :i* supplies u ) a clue to ?is subject4 ,x has be5 previ\sly /at$ t ! ocean is ess5tially ! !atre ( deposition1 ! l& t ( de/ruction1 & accord+ly1 ! pres5ce ( deposit z a g5]al rule indicates ! evid5ce ( m>9e conditions dur+ ! =mation ( ^? deposits1 ?\gh ?is is n univ]sally ! case4 ,aga91 z d5udation is practically conf9$ to ! l& areas1 & ! %all[-wat]s at _! m>g9s1 uncon=mity on a l>ge scale gives evid5ce ( ! exi/5ce ( t]re/rial conditions 9 ! area 9 :i* x is develop$1 dur+ its production4 ,accord+ly a mass ( deposit sep>at$ f deposits above & bel[ by m>k$ uncon=mities %[s ! alt]nation ( t]re/rial conditions 7dur+ :i* ! uncon=mity 0 produc$7 & m>9e conditions 7dur+ :i* ! deposits 7 laid d[n74 ,! deposits =m$ aft] an uncon=mity has be5 develop$ w naturally be ( %all[-wat] "*1 z w also be ^? ( ! p]iod imm$iately prec$+ ! incom+ ( conditions :i* w cause ! occurr5ce ( ano!r uncon=mity1 & betwe5 ^! two %all[-wat] p]iods w occur a p]iod :5 deep]-wat] conditions probably prevail$4 ,we c !re=e n only divide ! hi/ory ( any p>ticul> area into a s]ies ( *apt]s1 ( :i* e two successive ones w describe a cont95tal p]iod & a m>9e "o1 b ea* m>9e p]iod may be divid$ into ?ree phases--a %all[-wat] phase at ! comm5cem5t1 an int]m$iate deep]-wat] phase1 & a %all[-wat] phase at ! end4 ,^! phases are frequ5tly complicat$ by ! occurr5ce ( a ho/ ( m9or *anges1 b on elim9at+ ^!1 ! effects ( ! ?ree great phases are %[n by /udy ( ! nature ( ! /rata1 & _! recognition does mu* to simplify ! detail$ /udy ( ! /ratigraphical geology ( v>i\s p>ts ( ! e>?'s surface4 ,9 discrim9at+ betwe5 t]re/rial conditions & m>9e ones1 ! exi/5ce ( uncon=mities is ( great importance 9 m>k+ t]re/rial conditions & is (t5 ! only available evid5ce1 = no accumulations or deposits =m$ on ! l& may be pres]v$ to te/ify to ! t]re/rial conditions#ca4 ,:5 t]re/rial deposits & accumulations d occur1 !y are extremely important1 & x is necess>y to allude to ! po9ts :]e9 !y diff] f m>9e deposits4 ,footnote #ca3 ,! t]m t]re/rial is us$ above 9 opposition to m>9e1 to include ! conditions preval5t above sea-level4 ,! t]m cont95tal w\ld be bett] if x did n exclude insul> conditions4 ,accord+ly deposits =m$ 9 riv]s1 & fre%-wat] & salt-wat] lakes are spok5 ( z t]re/rial4 ,ap>t f organic cont5ts1 ! me*anically =m$ deposits ( riv]s & lakes resemble 9 g5]al *>act]s ! %all[-wat] deposits ( ! ocean1 ?\gh !y are usually less widely di/ribut$4 ,x is ! accumulations :i* h actually be5 =m$ z olian rocks1 or ^? :i* h be5 laid d[n z *emical precipitates 9 salt-lakes :i*1 by /udy ( li?ological *>act]s1 furni% ! mo/ conv9c+ evid5ce ( _! t]re/rial orig94 ,_m olian accumulations may be look$ ^u z soils1 if ! t]m soil be us$ 9 a special s5se to ref] to ! accumulations :i* are produc$ z ! result ( ! excess ( dis9tegration ov] transportation 9 an area1 :il/ o!rs are due to transport :i* has n be5 suffici5tly effective to c>ry ! mat]ial to ! sea4 ,:5 ! wea!r$ mat]ial accumulates above ! wea!r$ rock1 x dep5ds *iefly ^u climate :e!r ! dis9tegrat$ rock becomes m+l$ ) mu* decay$ organic matt] =m+ humus4 ,if ?is organic matt] exi/s 9 quantity1 ! probability is t ! accumulation is a t]re/rial "o1 ?\gh ?is is by no means necess>ily ! case1 = "u exceptional circum/ances a good deal ( humus may be deposit$ 9 ! sea1 z b5ea? ! mangrove-swamps :i* l9e ! coa/s ( "s regions1 & to g fur!r back1 9 ! case ( ! ,crom] ,=e/ s]ies ( ,plioc5e times1 or "s coals1 su* z ! ,wigan ,cannel ,coal ( ! ,c>bonif]\s /rata4 ,9 addition to ! "w ( wat]1 :i* affects bo? l& & sea-deposits1 ! l& is especially *>act]is$ by ! op]ations ( w9d & fro/ ^u x1 = ^! produce results :i* may frequ5tly s]ve to diff]5tiate a l&-accumulation f a deposit laid d[n b5ea? sea-level4 ,! effect ( w9d 9 r\nd+ ! gra9s ( s& :i* are bl[n by x is well-kn[n1 & samples ( ! 'millet-se$' s&s ( des]t regions are pres]v$ 9 mo/ museums4 ,! great] r\nd+ :i* *>act]ises w9d-borne z comp>$ ) wat]-borne s& gra9s is due1 9 great measure1 to ! great] friction betwe5 ! gra9s :5 c>ri$ by ! air ?an :5 swept along by ! wat]4 ,"u fav\rable circum/ances wat]-worn gra9s may become r\nd$1 especially :5 agitat$ by g5tle curr5ts sweep+ ov] a %oal#cb2 b a l>ge mass ( s&1 9 :i* mo/ ( ! gra9s h und]gone mu* r\nd+ s z to give rise to 'millet-se$' s&1 w nev]!less be probably =m$ by w9d-action except :]e a m>9e deposit is =m$ ( mat]ial l>gely d]iv$ f an e>li] olian "o4 ,! effect ( fro/ is to split rocks into fragm5ts :i* are m or less angul> be=e !y are subject$ to wat]-action4 ,! brok5 fragm5ts are prone to collect on slopes z screes1 & z any scree-mat]ial fall+ into ! sea is likely to become r\nd$ except "u conditions :i* r>ely prevail1 ! exi/5ce ( mu* scree-mat]ial 9 a rock sugge/s its t]re/rial orig94 ,glaci]s gave rise to t]re/rial mora9es1 :i* may occasionally be id5tifi$ z l&-accumulations by m]e inspection ( _! physical *>act]s1 b all geologi/s are aw>e ( ! difficulties ) :i* !y are confront$ :5 !y attempt to discrim9ate betwe5 t]re/rial & m>9e glacial deposits4 ,footnote #cb3 ,cf4 ,hunt1 ,a4 ,r41 ,! ,evid5ce ( ! ,sk]ries ,%oal on ! we>+ ( ,f9e ,s&s by ,waves1 ,trans4 ,devon4 ,assoc41 #ahhg1 vol4 ,,xix4 p4 #dih4 ,! exi/5ce ( mu* mat]ial among/ ! /ratifi$ rocks :i* has be5 precipitat$ f a /ate ( solution is an indication ( ! t]re/rial orig9 ( ! rocks1 :i* 7 laid d[n on ! floors ( ! inl& seas1 sep>at$ m or less completely f ! op5 ocean2 = ! wat]s ( ! ocean are capable ( reta9+ 9 solution all ( ! mat]ial :i* is br\ght d[n to !m1 & accord+ly precipitates ( c>bonate ( lime1 rock-salt1 gypsum & o!r comp\nds =m$ f solution1 are only =m$ on a l>ge scale 9 inl& lakes1 ?\gh !y may be =m$ to "s ext5t :5 ! wat] ( a lagoon is only slightly connect$ ) t ( ! op5 ocean1 & ! evaporation is great1 = in/ance 9 ! lagoons ( coral reefs4 ,c]ta9 physical features (t5 m>k ! deposits ( *emical orig91 cubical or hopp]-cry/als ( rock-salt may be dissolv$1 & ! holl[ aft]w>ds fill$ ) mud1 s t ! rock surfaces are sometimes m>k$ ) pseudomorphs ( mud aft] rock-salt4 ,sun-cracks & ra9-pr9ts impress$ on ! rock are n actual indications ( t]re/rial orig9 ( ! rocks on :i* !y are f\nd1 = ! %all[-wat] muds ( an e/u>y may be deposit$ 9 ! sea & yet expos$ to ! action ( ! air at l[ tide1 b !y m>k v %all[-wat] deposits :i* h be5 expos$ to ! atmosph]e imm$iately aft] _! =mation if n dur+ ! "t !y 7 =m$1 & !y frequ5tly occur among/ ! deposits ( inl& lakes4 ,x w be obs]v$ t ! *>act]s ( ! t]re/rial accumulations s]ve to di/+ui% !m to "s ext5t f ! m>9e ones1 b !y also enable "o to detect to "s degree ! actual conditions "u :i* ! accumulation 0 produc$1 :e!r on ! m\nta9-slope1 or 9 ! pla91 ! des]t or ! f51 ! riv]-bank or ! lake-floor4 ,! conditions ( =mation ( ! m>9e deposits may be di/+ui%$ )9 c]ta9 limits ) ease1 by exam9ation ( _! physical *>act]s1 = ! ne>-%ore deposits w g5]ally be co>s] & conta9 m me*anically-transport$ mat]ial ?an ! s$im5ts :i* accumulate at a great] di/ance f ! %ore1 ?\gh x is n safe to inf] t deposits are =m$ away f ! %ore on acc\nt ( ! abs5ce ( me*anically-transport$ s$im5ts4 ,9 di/ricts :]e ! me*anically-transport$ mat]ial is rapidly deposit$1 organic deposits ( great purity may =m close to ! coa/-l9e2 = in/ance1 :5 ! riv]s ( a c\ntry end 9 fjords1 ! me*anical s$im5ts are deposit$ 9 ! fjords1 & ! sea ar\nd ! coa/ is free f ?is s$im5t1 & !re ! organisms c build up deposits ( great purity2 & a simil> ?+ may happ5 :5 ! riv]s on "o side ( a c\ntry h %ort c\rses1 & d n c>ry d[n mu* s$im5t1 :i* occurs :5 ! wat]%$ is ne> ! coa/4 ,on ! "o h&1 clay may be =m$ 9 consid]able purity ne> ! coa/1 :]e ! supply ( mud is s great t ! organisms exi/+ !re c d little 9 ! way ( contribution to ! mass ( ! deposit1 or x may be =m$ on ! o!r h& 9 great dep?s ( ! ocean1 :]e ! supply ( s$im5t is extremely small1 b :]e all ! organic te/s become dissolv$2 z ! *>act]s ( ! deep sea clays are ma9ly negative1 a geologi/ exam9+ ! rocks ( ! geological column w\ld h mu* difficulty 9 di/+ui%+ a deep-wat] clay f a %all[-wat] "o by its li?ological *>act]s only4 ,9 cases ( difficulty1 in=mation ( importance is likely to be furni%$ by exam9ation ( ! relative ?ickness ( equival5t deposits 9 adjo9+ areas1 = if we f9d a mass ( clay a few feet ?ick 9 "o region repres5t$ by hundr$s ( feet ( clay & lime/one 9 ano!r1 ! =m] mass probably accumulat$ sl[ly & at "s di/ance f ! l&2 aga91 ! uni=mity ( li?ological *>act]s ( a deposit ov] a v wide area is a possible indication ( its =mation away f l&1 b ?is is n a safe guide1 = reasons :i* w ev5tually appe>1 unless x c be %[n t ! deposit is ev]y:]e ( ! same age4 ,a clue to climatic conditions is frequ5tly furni%$ by ! physical *>act]s ( accumulations1 especially t]re/rial ones4 ,! accumulations conta9+ a l>ge p]c5tage ( hydroc>bons h probably be5 =m$ "u fairly temp]ate & moi/ climatic conditions1 :il/ ! exi/5ce ( millet-se$ s&/ones associat$ ) *emical deposits po9ts to des]t conditions & inl& lakes1 requir+ a dry climate & probably a w>m "o4 ,glaciat$ surfaces & glacial deposits ( c\rse indicate a l[ temp]ature4 ,"s geologi/s pr(ess t occasionally !y c ev5 det]m9e ! direction ( ! prevail+ w9ds dur+ pa/ p]iods1 by exam9ation ( ! "* ( ripple-m>ks1 ra9-pits & o!r features1 ?\gh x is d\btful :e!r mu* reliance c be plac$ ^u ^! obscure indications4 ,useful z is ! physical evid5ce suppli$ by deposits1 z an index to ! conditions "u :i* !y 7 =m$1 x is usually only supplem5t>y to ! evid5ce d]iv$ f a /udy ( ! fossils4 ,fossils :5 pres5t 9 ! rocks1 usually supply consid]able in=mation conc]n+ ! preval5t conditions dur+ ! deposition ( ! rocks4 ,by !m we c n only sep>ate m>9e f t]re/rial deposits1 b also fre%wat] deposits f olian accumulations2 ea* k9d ( deposit w g5]ally conta9 ! rema9s ( organisms :i* exi/$ "u ! conditions preval5t 9 ! area ( =mation ( ! rock1 ?\gh x is ( c\rse a frequ5t ?+ = a t]re/rial creature or plant to be wa%$ into a fre%wat] area or into ! sea4 ,9 an olian deposit1 ! inv]tebrate rema9s may be ^? ( any air-brea?+ =ms1 z insects1 galley-worms1 spid]s1 scorpions & molluscs4 ,! l&-molluscs are all univalve4 ,( v]tebrates1 we may f9d ! bones & tee? ( amphibians1 reptiles1 birds & mammals4 ,occasionally fre%wat] or ev5 m>9e =ms may be f\nd 9 an olian deposit1 b !y w be exceptional4 ,m>9e %ells are (t5 bl[n among/ ! s&-gra9s ( ! coa/al dunes1 & seagulls & o!r birds frequ5tly c>ry m>9e organisms f> inl&4 ,! creatures frequ5t+ fre% wat] diff] f ^? ( ! l& & ( ! sea4 ,! mo/ abundant v]tebrate rema9s w be ^? ( fi%es1 & ( ! inv]tebrates we f9d mollusca prepond]ate4 ,! v>iety ( molluscs is n s great z 9 ! case ( m>9e faunas4 ,! bivalves always possess two muscul> sc>s on ea* valve 7except adult ,mull]ia72 :il/ _m m>9e %ells z ! oy/] h only "o muscul> sc> on ea* valve4 7,see ,fig4 #aa47 ,illu/ration3 ,fig4 #aa4 ,a4 ,monomy>y %ell ) "o sc>4 ,b4 ,dimy>y %ell ) two sc>s4 ,^! sc>s m>k ! atta*m5t ( ! adductor muscles1 = draw+ ! valves toge!r1 & ! %ells ) only "o impression on ea* valve are call$ monomy>y1 ^? ) two impressions dimy>y4 ,! discov]y ( monomy>y %ells indicates ) tol]able c]ta9ty ! m>9e "* ( ! deposit 9 :i* !y are f\nd1 ?\gh _! abs5ce _c be tak5 z pro( ( fre%wat] orig94 ,! beaks or umbones ( ! bivalves are (t5 corrod$ 9 fre%wat] deposits1 z may be se5 by exam9+ %ells ( ! common fre%wat] mussel4 ,all univalve %ells ( l& & fre%wat] species1 ) ! exception ( ,melanopsis & ,a*at9a1 :i* has a slight ind5tation1 h entire m\?s2 & ?is circum/ance may (t5 s]ve z a conv5i5t rule = di/+ui%+ fre%wat] f m>9e /rata2 s9ce if any univalves occur ( :i* ! m\?s are n entire1 we may presume t ! =mation is m>9e#cc4 ,footnote #cc3 ,lyell's ,/ud5ts' ,elem5ts ( ,geology1 ,second ,edition 7#ahgd71 ,*ap4 ,,iii4 ,a good acc\nt ( ! diff]5ces betwe5 fre%wat] & m>9e organisms1 f :i* "s ( ! facts "h cit$ are extract$1 w be !re f\nd4 ,illu/ration3 ,fig4 #ab4 ,a4 ,holo/omat\s %ell4 ,b4 ,siphono/omat\s %ell4 ,9 ,fig4 #ab ,a %[s a fre%wat] %ell 7,vivip>a7 ) entire m\?1 :il/ ,b exhibits ! %ell ( a m>9e ga/ropod 7,pleurotoma7 ) a not*$ m\?4 ,! entire-m\!d %ells are call$ holo/omat\s :il/ ^? :i* are not*$1 ! not* be+ (t5 prolong$ into a canal1 are t]m$ siphono/omat\s4 ,_m gr\ps ( inv]tebrates are seldom or nev] f\nd 9 fre% wat]4 ,( exclusively or ne>ly exclusively m>9e creatures we may "n ! =am9if]a1 radiol>ia1 sponges ) a h>d framework1 mo/ hydrozoa :i* secrete h>d p>ts1 corals1 e*9od]ms1 cirrip$es1 k+-crabs1 locu/-%rimps1 mo/ polyzoa1 bra*iopods1 pt]opods1 het]opods1 & cephalopods4 ,( ext9ct gr\ps1 ! graptolites & trilobites seem to h be5 entirely conf9$ to ! sea4 ,9 ! mod]n & comp>atively mod]n deposits1 ! =ms frequ5tly belong to exi/+ g5]a1 & we get fairly conclusive evid5ce ( ! conditions ( deposit by det]m9ation ( ! g5]a4 ,! t]re/rial 7includ+ fre%wat]7 molluscs h mo/ly a long range 9 "t4 ,we f9d pulmonif]\s ga/ropods ( liv+ g5]a 9 ! ,c>bonif]\s p]iod1 "o 7,d5dropupa7 belongs to a subg5us ( ! mod]n l&-%ell ,pupa1 ! o!r 7,zonites7 to a subg5us ( ! snail gr\p ,helix4 ,_m fre%wat] molluscs z ,unio1 ,cyclas1 & ,physa are f\nd among/ ! second>y rocks1 & give a clue to ! orig9 ( ! deposits :i* conta9 !m4 ,_m ext9ct g5]a are closely alli$ to mod]n g5]a1 & _! mode ( exi/5ce may be assum$ ) fair c]ta9ty4 ,) all ^! guides1 we may sometimes be left 9 d\bt z to ! conditions ( deposit :5 organisms are few 9 numb]2 ?us1 x is yet a matt] = discussion :e!r ! ,old ,r$ ,s&/one & _m ( ! deposits ( ! ,coal ,measures ( ,brita9 7 ( fre%wat] or m>9e orig94 ,9 consid]+ ! possibility ( fossils hav+ be5 c>ri$ f l& to wat] or vice v]sa1 x w be rememb]$ t g5]ally speak+ !y are m readily transf]r$ f a high] to a l[] level1 s we are m likely to f9d rema9s ( l&-animals & plants 9 fre% wat] or ! sea1 & relics ( fre%wat] animals & plants 9 ! sea1 ?an ( m>9e or fre%wat] animals & plants 9 l&1 or m>9e organisms 9 fre% wat]4 ,riv]-gravels & lacu/r9e deposits are especially prone to conta9 a consid]able int]mixture ( l&-=ms ) ^? prop] to ! /ation4 ,fossils supply mu* in=mation conc]n+ ! dep? & di/ance f l& at :i* ! deposits 7 laid d[n4 ,:5 portions ( ! ocean-wat] h be5 sep>at$ to =m inl& lakes1 ! wat] becomes salti] ?an t ( ! op5 ocean1 if ! evaporation is great] ?an ! supply ( fre% wat]1 & ! life ( ! inl& sea und]goes *ange "u ! unfav\rable conditions set up4 ,_m =ms disappe> altoge!r1 & ^? :i* survive t5d to become /unt$1 & ! %ells ( _m ( ! mollusca are abnormally ?92 ! fauna ( an inl& sea ?\gh x may h abundance ( individuals is apt to be *>act]is$ by paucity ( species4 ,turn+ n[ to ! faunas ( ! op5 oceans1 x is f\nd t 9 addition to latitude1 ! di/ribution ( organisms is affect$ by dep?1 & by ! nature ( ! sea-floor1 & accord+ly we f9d diff]5t organisms 9 diff]5t areas2 & 9 exam9+ ! same area ! organisms inhabit+ diff]5t dep?s are n all ! same1 & at ! same dep? "s k9ds ( animals h diff]5t /ations f ^? ( o!rs1 "o creature be+ conf9$ to a s&y floor1 ano!r to a muddy "o1 & s on#cd4 ,! oceans h be5 divid$ into #ah prov9ces1 ea* ( :i* is m or less *>act]is$ by ! possession ( peculi> =ms :i* are t]m$ endemic1 9 contra/ to ! sporadic =ms :i* are widely di/ribut$4 ,9 any area :i* is m>g9$ by a coa/ l9e1 ! molluscs are di/ribut$ 9 zones :i* 7 =m]ly class$ z foll[s3--! littoral zone betwe5 tide m>ks1 ! lam9>ian zone f l[ wat] to fifte5 fa?oms1 ! corall9e zone betwe5 fifte5 & fifty fa?oms1 & ! deep-sea coral zone f fifty fa?oms to "o hundr$ fa?oms or m2 ?is la/ dep? 0 once suppos$ to m>k ! limit ( ! d[nw>d ext5sion ( m>9e life1 b z ! result ( mod]n deep-sea s\nd+s we "k t organisms ext5d to a mu* great] dep?1 & ! deep-sea fauna1 ow+ to uni=mity ( conditions ov] wide areas1 conta9s few] endemic =ms 9 proportion to ! sporadic ones ?an ! %all[-wat]#ce4 ,! deep-sea deposits entomb ! rema9s ( ^! deep-sea organisms & also ( num]\s pelagic organisms :i* live ^u ! surface ( ! ocean1 ^: rema9s s9k to ! ocean-floor aft] dea?4 ,among/ ! deposits ( ! deep] p>ts ( ! ocean1 we f9d _m :i* are almo/ exclusively compos$ ( ! te/s ( =am9if]a1 radiol>ia & pt]opods1 ! spicules ( sponges1 & ! fru/ules ( diatoms2 & accord+ly ! exi/5ce ( =am9if]al1 pt]opodan1 radiol>ian1 & diatomace\s oozes1 among/ ! /rata ( ! geological column1 has be5 tak5 by "s z indicat+ ! preval5ce ( deep-sea conditions dur+ ! =mation ( ^? deposits3 z ! purity ( a calc>e\s ooze dep5ds ^u ! abs5ce ( me*anical s$im5t1 or volcanic du/1 & z ! compon5t organisms ( ^! oozes are pelagic =ms :i* live ne> ! cont95ts z well z 9 ! op5 oceans1 ! pres5ce ( calc>e\s oozes implies ! exi/5ce ( a cle> sea dur+ _! deposition b n necess>ily ( a deep "o1 = if ! sea-area be f> away f l& masses1 or if ! s$im5t be /ra9$ (f 9 fjords1 calc>e\s oozes may be =m$ 9 %all[ wat]4 ,! exi/5ce ( pure radiol>ian or diatomace\s deposits is bett] evid5ce ( deep wat]1 = if !y 7 =m$ 9 %all[ wat] we %\ld expect an int]mixture ( calc>e\s te/s1 :]eas ^! are dissolv$ :il/ s9k+ into ! extreme dep?s ( ! ocean4 ,z ! deep-sea creatures are "u v diff]5t conditions f ^? ( %all[] wat]s1 we might expect m>k$ /ructural diff]5ces betwe5 ! deep & %all[-wat] creatures3 "o su* diff]5ce has be5 emphasiz$1 namely ! occurr5ce ( animals :i* are bl9d or h enorm\sly develop$ eyes 9 ! great dep?s ( ! sea1 :]e ! only light is due to phosphoresc5t organisms4 ,?is is well se5 9 ! case ( _m rec5t cru/acea1 & has be5 not$ by ,suess 9 ! case ( ! trilobites ( "s b$s :i* he accord+ly inf]s to be ( deep-wat] orig91 & x is int]e/+ to f9d t ^! creatures are f\nd 9 deposits :i* give indep5d5t evid5ce ( an op5-wat] orig94 ,! gl9 ( ! ,ordovician /rata are frequ5tly furni%$ ) enorm\s eyes1 & !y are (t5 accompani$ by bl9d trilobites1 & 9 ,bohemia ! bl9d & l>ge-ey$ =ms are sometimes diff]5t species ( ! same g5us1 = in/ance ,illnus#cf4 ,footnote #cd3 ,= an acc\nt ( ! di/ribution ( "o gr\p ( organisms see ,woodw>d1 ,s4 ,p41 ,a ,manual ( ! ,mollusca1 f :i* _m ( ! foll[+ obs]vations are tak54 ,footnote #ce3 ,= an acc\nt ( ! deep-sea fauna1 see ,hickson1 ,s4 ,j41 ,! ,fauna ( ! ,deep ,sea1 #ahid4 ,footnote #cf3 ,suess1 ,e41 ,das ,antlitz d] ,erde1 #b;er4 ,bd41 p4 #bff4 ,z "o w\ld naturally expect1 ! actual dep? at :i* deposits 7 =m$ c g5]ally be calculat$ ) a great] degree ( c]ta9ty among/ ! new] rocks ?an among/ ! old] ones4 ,9 ! case ( ! ,plioc5e ,crags1 ! dep? 9 fa?oms may be confid5tly giv54 ,9 ! ,cretace\s rocks attempts h be5 made to give num]ical e/imates ( ! dep?s at :i* diff]5t accumulations 7 =m$1 b "s diff]5ces ( op9ion h aris5 9 ! case ( ^! rocks4 ,9 ! ,palozoic rocks1 only a r\gh idea ( ! g5]al dep? c usually be obta9$1 & no attempt to calculate ! dep? 9 fa?oms is likely to be ev5 approximately correct 9 ! pres5t /ate ( our k4 ,! comm9ution ( fossils has sometimes be5 tak5 z an indication ( %all[] wat] orig9 ( ! deposits :i* conta9 !m1 b al?\gh ! h>d p>ts ( organisms 9 a brok5 condition h frequ5tly be5 %att]$ by ! action ( ! waves1 !y may also be brok5 at great dep?s by pr$ace\s creatures1 & 9 _m in/ances ! fracture is ! result ( e>?-movem5ts occurr+ subsequ5tly to ! =mation ( ! deposits4 ,turn+ n[ to ! diff]5ce 9 organisms :i* results f diff]5ce ( /ation1 x w be suffici5t to give a quotation f ,woodw>d's ,manual ( ! ,mollusca z an illu/ration3--,9 ,europe ! *>act]i/ic g5]a ( rocky %ores are ,littor9a1 ,patella1 & ,purpura2 ( s&y bea*es1 ,c>dium1 ,tell9a1 ,sol52 gravelly %ores1 ,mytilus2 & on muddy %ores1 ,lutr>ia & ,pulla/ra4 ,on rocky coa/s are also f\nd _m species ( ,haliotis1 ,siphon>ia1 ,fissurella1 & ,tro*us2 !y occur at v>i\s levels1 "s only at ! high-wat] l9e1 o!rs 9 a middle zone1 or at ! v]ge ( l[-wat]4 ,cypra & ,conus %elt] "u coral-blocks1 & ,c]i?ium1 ,t]ebra1 ,natica & ,pyramidella bury 9 s& at l[-wat]1 b may be f\nd by trac+ ! m>ks ( _! long burr[s 7,macgillivray7#cg4 ,footnote #cg3 ,woodw>d1 ,s4 ,p41 ,a ,manual ( ! ,mollusca1 p4 #aea4 ,! geologi/ w naturally select sporadic =ms r ?an endemic ones 9 comp>+ ! /rata ( diff]5t areas1 b h[ f> diff]5ces 9 faunas are ! result ( exi/5ce at diff]5t times1 & h[ f> !y are due to diff]5ce ( conditions affect+ contemporane\s organisms c only be discov]$ z ! result ( accurate obs]vation4 ,! ma9 po9ts to be reg>d$ :5 comp>+ ! successive faunas ( diff]5t regions h be5 notic$ 9 ?is & ! prec$+ *apt]s1 & x has be5 %[n t z ! evid5ce is cumulative1 x requires ! collection ( a l>ge numb] ( facts obta9$ by obs]vation ( ! /rata be=e accurate inf]5ces c be drawn4 ,! indications ( climatic conditions furni%$ by organisms require "s consid]ation4 ,9 ! comp>atively rec5t deposits x is n difficult to get "s notion ( ! preval5t climatic conditions :5 ! fossils belong to =ms closely relat$ to mod]n g5]a4 ,! exi/5ce ( ! arctic bir* & arctic will[1 & ( %ells belong+ to species n[ liv+ nor? ( ! ,briti% ,isles1 9 deposits ( comp>atively rec5t date 9 ,brita9 w\ld af=d conv9c+ evid5ce ( ! occurr5ce ( cold] climatic conditions ?an ^? :i* are n[ preval5t 9 ! area1 ev5 if ! evid5ce 7 n confirm$ z x is1 by physical pro( ( glaciation 9 deposits ( ! same age4 ,nev]!less1 ev5 9 ^! rec5t b$s1 we h a useful w>n+1 by f9d+ species ( elephant & rh9oc]os associat$ ) nor!rn =ms l ! lemm+1 glutton1 & musk-ox4 ,we "k t ! species ( elephant & rh9oc]os 7! mammo? & woolly rh9oc]os7 7 provid$ ) ?ick cov]+s :i* w\ld enable !m to resi/ ! sev]ity ( an arctic climate1 b _h n ^! cov]+s be5 f\nd1 we might h be5 puzzl$ by ! association ( =ms ^: ne>e/ allies are sub-tropical ) o!rs ( arctic "*4 ,z we g back 9 "t & deal ) e>li] deposits1 ! asc]ta9m5t ( ! climatic conditions becomes m difficult1 z ! fossils mo/ly belong to ext9ct species1 g5]a or ev5 families4 ,9 ^! circum/ances1 x is v dang]\s to draw conclusions z to climatic conditions f exam9ation ( a few =ms1 b :5 we f9d t plants & animals1 t]re/rial & m>9e =ms1 v]tebrates & inv]tebrates alike po9t to ! same conclusion1 z 9 ! ,london ,clay1 :]e all ! fossils belong to =ms alli$ to ^? n[ liv+ "u sub-tropical conditions1 ! /ate ( ! climate may be inf]r$ ) consid]able c]ta9ty#ch4 ,! "* ( ! fossils mu/ be tak5 into acc\nt r ?an _! size4 ,!re 0 a t5d5cy among/ geologi/s to believe t l>ge organisms probably indicate w>m conditions4 ,rec5t rese>*es 9 arctic seas h dispell$ ?is belief4 ,m>9e alg ( enorm\s size are f\nd 9 ! cold seas1 & ! size ( creatures1 abundance ( individuals & v>iety ( =ms 9 ! arctic faunas ( "s regions is v notewor?y4 ,9 ! ,k>a ,sea1 = in/ance1 a v>iety ( creatures 7 dr$g$ up dur+ ! voyage ( ! ,vega1 & ,b>on ,nord5skjld makes ! foll[+ p]t95t rem>ks ab\t !m3 ,= ! sci5ce ( our "t1 :i* s (t5 places ! orig9 ( a nor!rn =m 9 ! s\?1 & vice v]sa1 z ! f\ndation ( v wide !oretical conclusions1 a k ( ! types :i* c live by turns 9 ne>ly fre% wat] ( a temp]ature ( #aj1 & 9 wat] cool$ d[n to -#bg & ( ne>ly ! same sal9ity z t ( ! ,m$it]ranean1 mu/ h a c]ta9 int]e/4 ,! mo/ rem>kable 71 accord+ to ,dr ,/uxb]g1 ! foll[+3 a species ( ,mysis1 ,dia/ylis ,ra?kei ,kr41 ,ido!a entomon ,l941 ,ido!a ,sab9ei ,kr41 two species ( ,lysianassida1 ,pontoporeia setosa ,/brg41 ,halim$on brevicalc> ,gs1 an ,annelid1 a ,molgula1 ,yoldia int]m$ia ,m4 ,s>s1 ,yoldia 787 arctica ,gray1 & a ,solecurtus#ci4 ,! temp]atures 7 tak5 by a c5tigrade !rmomet]4 ,aga9 we read ( ! results ( dr$g+ (f ,cape ,*elyusk94 ,! yield ( ! trawl+ 0 extraord9>ily abundant2 l>ge a/]ids1 cr9oids1 sponges1 holo?uria1 a gigantic sea-spid] 7,pycnogonid71 masses ( worms1 cru/acea1 etc4 ,x 0 ! mo/ abundant yield t ! trawl-net at any "o "t br\ght up dur+ ! :ole ( our voyage r\nd ! coa/ ( ,asia1 & ?is f ! sea (f ! nor!rn extremity ( t cont95t#dj4 ,footnote #ch3 ,= a discussion z to ! value ( plants z indices ( climate see ,sew>d1 ,a4 ,c41 ,s$gwick ,essay = #ahib4 ,footnote #ci3 ,nord5skjld1 ,a4 ,e41 ,! ,voyage ( ! ,vega1 ,vol4 ,i4 ,*ap4 ,,iv4 ,footnote #dj3 ,ibid4 ,*ap4 ,,vii4 ,among/ ! m>9e inv]tebrates reef-build+ corals & mollusca p]haps furni% ! be/ evid5ce ( climatic conditions4 ,! coral-reefs ( ! ,jurassic rocks ) l>ge ga/ropods & lamellibran*s clu/]$ ar\nd !m h be5 appeal$ to 9 pro( ( ! exi/5ce ( sub-tropical conditions dur+ _! =mation2 fur!r back 9 "t we f9d evid5ce ( climate furni%$ by ! fossils ( ! ,silurian rocks ( ! ,isle ( ,go?l& 9 ! ,baltic ,sea4 ,( ^!1 ,l9d/rm writes ,! fauna _h a tropical "*4 ,9 consid]ation ( ! great numb]s ( ,pleurotom>iae1 ,tro*i1 ,turb9idae & ! l>ge ,pt]opods ! assumption ( a tropical "* ( ! fauna may seem ju/ifiable#da4 ,footnote #da3 ,l9d/rm1 ,g41 ,on ! ,silurian ,ga/ropoda & ,pt]opoda ( ,gotl&1 ,/ockholm1 #ahhd1 p4 #cc4 ,/ructure may give "s indication ( climate ev5 ?\gh ! organism is n alli$ to liv+ species4 ,! b>k ( trees 9 arctic regions is (t5 ?ick] ?an 9 m temp]ate regions1 & ! leaves ( arctic plants (t5 h special *>act]s to enable !m to resi/ ! long p]iods dur+ :i* !y are depriv$ ( wat]1 ?\gh ! fact t des]t-plants frequ5tly %ew simil> modifications deprives ?is te/ ( any p>ticul> value except z a means ( corroborat+ conclusions rea*$ f o!r evid5ce#db4 ,! %ells ( arctic mollusca may become /unt$1 b ?is is n by any means univ]sal1 & ! same result may be br\ght ab\t by o!r abnormal conditions1 z = in/ance ! increase ( salt 9 a wat] area by evaporation4 ,footnote #db3 ,= an acc\nt ( ! modifications ( ! leaves ( arctic plants1 see ,w>m+1 ,eug41 ,om ,grnl&s ,vegetation1 ,m$delels] om ,grnl&1 #ab? "p1 p4 #aje4 ,on ! :ole1 an exam9ation ( ! evid5ce available = asc]ta9+ ! "* ( climate by ref]5ce to includ$ organisms1 %ews t inf]5ces may be drawn )9 c]ta9 limits1 b t ! task is a difficult "o n unaccompani$ by dang]1 & e k9d ( available evid5ce d]iv$ f a /udy ( physical ph5om5a & ! includ$ organisms %\ld be utilis$ be=e any conclusion is drawn4 ,! likelihood ( accurate inf]5ce is increas$ by comp>+ ! faunas ( v>i\s areas2 %\ld !y seem to indicate a progressive l[]+ ( climate :5 pass+ f l[] to high] latitudes1 x is probable t ! indication is correct4 ,! /ud5t is ref]r$ to a pap] by ! late ,pr(essor ,neumayr = an acc\nt ( ! exi/5ce ( climatic zones dur+ ! ,mesozoic ,p]iod#dc4 ,footnote #dc3 ,neumayr1 ,m41 ,ueb] klimatis*e ,zon5 whr5d d] ,jura- und ,kreidezeit1 ,d5ks*rift4 d] ,ma?4-,naturwiss5s*4 ,classe d] k4 ,akad4 d] ,wiss5s*aft51 ,bd4 ,,xlvii4 ,vi5na1 #ahhc4 ,,*apt] ,x4 ,,evid5ces ,,( ,,conditions ,,"u ,,:i* ,,/rata ,,7 ,,=m$1 ,,cont9u$4 ,9 ! prec$+ *apt]1 att5tion 0 drawn to ! indications z to conditions ( deposition furni%$ by ! s$im5ts ( any "o locality1 & only pass+ ref]5ce 0 made to v>iation 9 ! nature ( ! s$im5ts & _! organic cont5ts1 :5 ! deposits are trac$ lat]ally f place to place2 "s att5tion mu/ n[ be paid to ?is matt]4 ,x is sometimes inf]r$ t1 :]eas simil>ity ( organisms is a dang]\s guide 9 correlat+ ! /rata ( two areas1 accurate correlations may be made1 if ! deposits c be trac$ cont9u\sly ?r\gh ! int]v5+ int]val2 no d\bt ! task is simplifi$ :5 ?is c be done1 b ! cont9uity ( deposit ( "o p>ticul> composition is no m pro( ( contemporaneity ?an ! occurr5ce ( ! same fossils cont9u\sly ?r\gh ! int]val1 imb$d$ 9 /rata ( diff]5t "*1 inde$ probably n s mu* s4 ,! exi/5ce ( widespread masses ( conglom]ate1 :i* are n f\nd z l9e> /rips1 b :i* ext5d 9 all directions1 is 9 itself an indication ( ?is2 ! ,oldhav5 pebble b$ = in/ance1 9 ! ,t]ti>y rocks ( ! ,london bas91 is v widely di/ribut$4 ,we _c suppose t coa/al conditions prevail$ f> away f ! %ore-l9e1 & accord+ly :5 a conglom]ate occurs 9 a widespread %eet1 & n 9 a l9e> /rip1 ?is is indicative t ! deposit has n be5 =m$ cont9u\sly b t /rip has be5 add$ to /rip along an advanc+ or rec$+ %ore l9e1 & if ?is happ5s ) conglom]ates1 x mu/ occur also 9 ! case ( o!r deposits4 ,illu/ration3 ,fig4 #ac4 ,9 fig4 #acdd let ,a repres5t a %ore l9e ( a cont95t :i* is und]go+ gradual elevation4 ,a deposit ( pebbles a w be =m$ aga9/ ! coa/1 "o ( s& b fur!r away1 !n "o ( mud c & la/ly lime/one d1 may be =m$ 9 ! op5 sea away f l&4 ,naturally !re may be int]m+l+ ( two k9ds ( deposit at ! junctions1 b = ! sake ( simplicity ?is may be disreg>d$4 ,dur+ ! accumulation ( ! deposits a1 b1 c1 d1 c]ta9 sporadic =ms may be di/ribut$ ?r\gh\t all ! deposits1 & "s ( !m may become ext9ct be=e ! deposition ( ^! b$s is complet$1 if ! process is c>ri$ out on a l>ge scale2 we may speak ( ! *>act]i/ic fossils ( ?is p]iod z fauna ,i4 ,z ! result ( elevation or ( m]e silt+ up ( ! sea-m>g91 or ( bo? comb9$1 ! next mass ( pebble-deposit w be laid d[n fur!r away f ! orig9al %ore1 = ! %ore l9e w n[ be at ,a & n at ,a1 & x w p>tly ov]lap ! mass ( s& b2 ! s& b#a w also be deposit$ some:at fur!r out & p>tly ov]lap ! mud c1 & simil>ly ! mud c#a w p>tly ov]lie ! lime/one d4 ,dur+ ! =mation ( a#a1 b#a1 c#a1 d#a1 o!r sporadic =ms belong+ to a fauna ,,ii may replace ^? ( ! fir/ fauna4 ,9 ! same way a#b1 b#b1 c#b1 d#b w be deposit$1 & 9 ! meantime a new fauna ,,iii may arise & replace ,,ii4 ,s ! process w g on until we f9ally h a gr\p ( deposits ly+ "o ov] ! o!r1 consi/+ ( a basal accumulation ( lime/one1 succe$$ by mud1 s&/one & pebble-b$s 9 succession4 ,ea* ( ^! w be cont9u\s1 ?\gh ! inn] "p ( ! pebble-deposit 0 =m$ long be=e ! out] "p ( ! lime/one1 :i* is nev]!less b5ea? a mass ( pebble-deposit cont9u\s ) t =m$ fir/1 & ! v>i\s deposits w be sep>at$ by fairly horizontal planes x1 y1 z1 :i* might be reg>d$ z b$d+ planes1 b :i* are n s1 /rictly speak+4 ,! true b$d+ planes w occur at a slight angle to ^! planes ( sep>ation1 = ! /ructure resembles false b$d+ on a gigantic scale1 b ( c\rse1 ! l9es sep>at+ two masses ( simil> deposit w be practically horizontal & p>allel to ! planes ( dem>cation ( two di/9ct k9ds ( mat]ial4 ,! l9es sep>at+ two faunas w\ld1 "u ! conditions po/ulat$1 run approximately p>allel to ! planes ( sep>ation ( adjo9+ deposits ( ! same li?ological "* b w\ld pass f conglom]ate1 ?r\gh s&/one1 mud & lime/one1 z indicat$ by ! l9es #a1 #b1 #c1 444 & ! deposits betwe5 adjo9+ l9es w\ld be contemporane\s#de4 ,9 nature1 complications w arise1 ow+ to ! gradual appe>ance & disappe>ance ( =ms1 & ! exi/5ce ( endemic species 9 contemporane\s deposits =m$ 9 diff]5t /ations & hav+ diff]5t li?ological *>act]s4 ,footnote #dd3 ,! writ] gratefully ackn[l$ges 8 indebt$ness to ,pr(4 ,lapwor? = "s ( 8 views conc]n+ deposition ( /rata4 ,footnote #de3 ,! l9es #a1 #b1 #c 444 are incorrectly drawn 9 ! figure4 ,l9e #a %\ld be drawn s z to sep>ate a1 b1 c1 d f a#a1 b#a1 c#a1 d#a1 l9e #b to sep>ate a#a1 b#a1 c#a1 d#a f a#b1 b#b1 c#b1 d#b1 & s ) ! o!rs4 ,if elevation ceas$ & 7 succe$$ by depression1 ! exact opposite w\ld occur1 & ! pebble b$s w\ld be ov]la9 by s&/ones1 ^! by muds1 & la/ly lime/ones w\ld appe>4 ,x foll[s t dur+ a m>9e phase occurr+ betwe5 two uncon=mities we %\ld h a ,v-%ap$ accumulation ( deposits ) ! apex po9t+ to ! "p ( ! %ore l9e :i* 0 la/ subm]g$ be=e ! comm5cem5t ( elevation1 z %ewn 9 fig4 #ad1 ?\gh ! b$s ( ! apex w 9 mo/ cases be d5ud$ dur+ ! re-em]g5ce4 ,illu/ration3 ,fig4 #ad4 ,indications ( ! non-co9cid5ce ( ! planes sep>at+ faunas & ^? :i* sep>ate deposits ( "o li?ological "* f ^? ( ano!r h already be5 detect$1 = in/ance ! 'gre5s&' condition ( ! ,cretace\s p]iod occurs 9 "s places dur+ ! exi/5ce ( "o fauna1 & 9 o!rs dur+ t ( ano!r1 ?\gh ! planes h n be5 trac$ cont9u\sly4 ,mr ,lamplugh has furni%$ ano!r example among/ ! ,cretace\s rocks ( ,york%ire & ,l9coln%ire1 b z has already be5 obs]v$1 a great deal rema9s to be done 9 ?is direction1 & geologi/s are mu* 9 want ( two sets ( /ratigraphical maps1 9 "o ( :i* ! l9es are drawn ) ref]5ce to ! diff]5ces ( li?ological "*1 :il/ 9 ! o!r !y sep>ate diff]5t faunas4 ,! /ud5t w notice ! normal recurr5ce ( deposits 9 def9ite ord]2 conglom]ate succe$$ by s&/one1 mud & lime/one1 9 a s9k+ area1 & lime/one succe$$ by mud1 s&/one & conglom]ate 9 a ris+ area4 ,naturally _m in/ances ( dep>ture f ?is rule are se51 ow+ to local conditions1 b on a l>ge scale1 x is v frequ5tly not$1 & recognition ( ?is w enable ! /ud5t to rememb] ! v>iations 9 ! li?ological *>act]s ( ! deposits m easily1 ?an if he simply acquir$ !m f a text-book )\t tak+ he$ z to _! significance4 ,^u ! v>iations 9 ! li?ological *>act]s ( deposits & ( _! faunas1 :5 ! b$s are trac$ lat]ally dep5ds v l>gely ! successful asc]ta9m5t ( ! exi/5ce ( =m] coa/-l9es1 ! re/oration ( :i* con/itutes an important "p1 ( ,palo-physiography1 conc]n+ :i* "s obs]vations may "h be made#df4 ,if a set ( deposits hav+ diff]5t li?ological *>act]s c be prov$ to be contemporane\s1 ! co>s] detrital accumulations w po9t to ! approa* to a coa/-l9e1 & ! actual position ( ! coa/ dur+ ! p]iod ( accumulation ( ! deposits may be v accurately fix$4 ,! pebble-b$s at ! base ( ! ,cambrian rocks ( ,llanb]is indicate ! exi/5ce ( a coa/-l9e 9 t position dur+ ! accumulation ( ^? pebble-b$s4 ,simil> pebble-b$s occur at ,/ ,david's1 at ! base ( ! ,cambrian1 b x is impossible 9 ! case ( ^! rapidly accumulat$ s$im5ts to say t two deposit$ s f> away f "o ano!r 7 actually contemporane\s1 & !re=e al?\gh we might draw a l9e ?r\gh ,llanb]is & ,/ ,david's to indicate ! old coa/-l9e ( ! p]iod1 x does n foll[ t ! actual bea* exi/$ simultane\sly at ! positions indicat$4 ,! palo-physiograph]1 h[ev]1 attempts to re/ore ! physical conditions ( great] ?icknesses ( deposit2 = in/ance1 ! di/ribution ( l& & sea dur+ ,l[] ,c>bonif]\s times ov] ! area n[ occupi$ by ! ,briti% ,isles is (t5 tak5 to illu/rate ! me?ods ( re/oration ( anci5t features1 & all admit t ! li?ological & palontological *>act]s ( ! rocks indicate a %all[+ ( ! ,c>bonif]\s sea :5 pass+ nor?w>ds t[>ds ,scotl&4 ,= convey+ an idea ( ! re/orations to ! /ud5t1 x is almo/ imp]ative to portray ! di/ribution ( l& & sea ^u a map1 & ?is c only be done by draw+ def9ite l9es4 ,x mu/ be di/9ctly und]/ood t ^! l9es are necess>ily only an approximation to ! actual position ( ! anci5t %ore-l9es1 :i* mu/ h %ift$ aga9 & aga9 dur+ ! long p]iod occupi$ by ! accumulation ( ! ,l[] ,c>bonif]\s /rata1 s t a true idea ( ! positions ( ! ,l[] ,c>bonif]\s %ore-l9es c\ld only be obta9$ by plac+ on a s]ies ( maps ! successive %ore-l9es ( diff]5t p>ts ( ! ,l[] ,c>bonif]\s p]iod1 & tak+ a composite photograph ( ^!1 :i* w\ld appe> z a wide belt ( %ad$ portion ( ! map ) no def9ite b\nd>ies4 ,! utmo/ t ! mak] ( palo-physiographical maps c expect to indicate1 :5 deal+ ) consid]able ?icknesses ( /rata1 is an approximation to ! mean position ( ! %ore-l9es ( ! p]iod :5 ^! /rata 7 deposit$4 ,?is is extremely valuable 9 enabl+ ! /ud5t to und]/& ! significance ( ! v>iations 9 ! *>act]s ( ! /rata & _! organic cont5ts1 if he di/9ctly recognises ! g5]alis$ nature ( ! map4 ,exam9ation ( any two palo-physiographical maps ( ! same p]iod by diff]5t au?ors w %ew wide div]g5ces 9 ! details1 b a g5]al resemblance ( ! ma9 features4 ,! read] w d well to consult ,pr(4 ,hull's re/oration ( ! physical features ( ,old ,r$ ,s&/one & ,l[] ,c>bonif]\s ,times on ,plate ,,vi4 ( 8 ,contributions to ! ,physical ,hi/ory ( ! ,briti% ,isles1 & comp>e x ) ! map drawn by ,pr(4 ,gre5 7,coal3 its ,hi/ory & ,uses1 by ,pr(s4 ,gre51 ,miall1 ,?orpe1 ,rck]1 & ,m>%all1 ,fig4 #c1 p4 #ch71 :i* w be f\nd to be> out ?is /atem5t4 ,footnote #df3 ,on ?is subject1 ! /ud5t may consult ,pr(4 ,e4 ,hull's ,contributions to ! ,physical ,hi/ory ( ! ,briti% ,isles4 ,valuable z ! publi%$ maps ( palo-physiography are z an aid to ! /ud5t 9 und]/&+ ! significance ( ! v>iations ( *>act]s among/ ! s$im5ts1 he w d well to supplem5t !m by maps :i* he fills 9 = himself4 ,he is recomm5d$ to procure a numb] ( outl9e maps ( ,engl&1 or ( ! ,briti% ,isles1 & :5 /udy+ 9 detail ! *>act]s ( ! ,briti% s$im5t>y rocks =m$ dur+ ! v>i\s p]iods1 to place a blank map by 8 side :5 beg9n+ ! /udy ( ea* p]iod or important portion ( a p]iod4 ,on ?is map he %\ld jot d[n ! geographical di/ribution ( ! diff]5t k9ds ( s$im5ts1 us+ ! conv5tional signs indicat$ at p4 #ij3 ?us1 9 ! case ( ! ,l[] ,c>bonif]\s rocks he w\ld place ! conv5tional sign = lime/one 9 ,d]by%ire1 a comb9ation ( ^? = lime/one & %ale 9 ,york%ire1 & w\ld add to ^! ! s&/one sign 9 ,nor?umb]l&4 ,he %\ld also note ! g5]al "* ( ! fossils1 us+ abbreviations = su* t]ms z fre%-wat] fossils1 %all[-sea fossils1 deep-wat] fossils4 ,aft] read+ ! acc\nt ( ! gr\p ( rocks 9 a compreh5sive text-book1 & ins]t+ 8 notes on ! map1 he %\ld proce$ to ins]t ! probable position ( ! coa/-l9es4 ,he %\ld also take notes ( any indications ( contemporane\s volcanic action1 ?\gh ^! might well be ins]t$ on a sep>ate map4 ,if ?is c\rse be pursu$1 ! /ud5t w n only h ! significance ( ! v>iations among/ ! /rata impress$ ^u 8 m9d1 b he w h a means ( obta9+ at a glance ! di/ribution ( s$im5ts & faunas ( diff]5t k9ds 9 ! ,briti% area dur+ ! pr9cipal geological p]iods4 ,on ano!r set ( maps he may indicate ! axes ( ! orog5ic movem5ts :i* h occurr$ at diff]5t times1 & :5 8 v>i\s maps are complet$1 he w h ! mat]ials = ! con/ruction ( a g5]al acc\nt ( ! v>i\s geological processes :i* h be5 conc]n$ ) ! build+ ( ! ,briti% area4 ,:5 an area l ,brita9 has be5 /udi$1 ! /ud5t may proce$ to con/ruction ( maps ( wid] regions1 & he w f9d t 9 do+ ?is1 new sets ( facts mu/ be tak5 into consid]ation1 z = in/ance ! occurr5ce ( diff]5t faunas on opposite sides ( once-exi/+ cont95tal masses1 & ! problems connect$ ) ! pres5t di/ribution ( ! faunas & floras4 ,= an in/ance ( ! importance ( ! =m] di/ribution ( life ! read] may consult ! twelf? section ( ! fir/ "p ( ,pr(essor ,suess' ,das ,antlitz d] ,erde1 :il/ a good acc\nt ( ! value ( rec5t geographical di/ribution ( organisms 9 supply+ a clue to =m] di/ribution ( l& & sea w be f\nd 9 ,mr ,a4 ,r4 ,wallace's ,isl& ,life1 ,*apt] xxii4 ,%\ld ! me?od sugge/$ above be adopt$1 ! /ud5t is likely to acquire a mu* m coh]5t idea ( ! significance ( ! facts ( /ratigraphical geology ?an c be obta9$ by a m]e p]usal ( ! acc\nts ( ! /rata giv5 9 ^? portions ( ! v>i\s text-books :i* are devot$ to a consid]ation ( ! /ratigraphical bran* ( ! sci5ce4 ,,*apt] ,,xi4 ,,! ,,classification ,,( ,,! ,,/ratifi$ ,,rocks4 ,9 ! succe$+ *apt]s1 a g5]al acc\nt ( ! *>act]s ( ! ,geological ,deposits ( diff]5t p]iods w be giv51 = ! purposes ( illu/rat+ ! pr9ciples to ! consid]ation ( :i* ! e>li] *apt]s h be5 devot$4 ,x is n propos$ to ent] into a description ( numb]less details1 :i* w\ld only confuse ! /ud5t :o wi%$ to grasp ! ma9 pr9ciples1 = _m facts h be5 record$ :i* x is necess>y to notice 9 a compreh5sive text-book treat+ ( /ratigraphical geology1 ?\gh _! full significance is n yet grasp$4 ,! writ]1 :ile not+ ! ma9 *>act]s ( ! v>i\s subdivisions ( ! diff]5t /ratigraphical sy/ems1 w assume t ?is "w is us$ 9 conjunction ) "s recognis$ text-book4 ,! /ratigraphical portion ( ,sir ,a4 ,geikie's ,class ,book ( ,geology gives an admirable g5]al acc\nt ( ! ,briti% ,/rata1 :ile ! l>g] text-book by ! same au?or has a cond5s$ ?\gh v full acc\nt ( ! rocks ( ! /ratigraphical column 9 all p>ts ( ! _w1 & ?is is supplem5t$ by num]\s ref]5ces to ! orig9al works :]e9 fur!r descriptions may be f\nd4 ,! ,engli% edition ( ,pr(4 ,e4 ,kays]'s ,text-,book ( ,comp>ative ,geology1 edit$ by ,p4 ,lake1 is also well adapt$ to ! wants ( ! /ud5t1 & an excell5t acc\nt ( ! /rata is giv5 9 ,mr ,a4 ,j4 ,jukes-,br[ne's ,h&book ( ,hi/orical ,geology1 :i* may be read ) ! same au?or's ,build+ ( ! ,briti% ,isles4 ,! read] :o ref]s to diff]5t text-books w be /ruck ) ! v>iations ( nom5clature ev5 among/ ! l>g] /ratigraphical divisions1 = two au?ors seldom subdivide ! geological column into ! same numb] ( rock-sy/ems4 ,! foll[+ classification w be "h adopt$3-- ,gr\ps4 ,sy/ems4 ,rec5t ,plei/oc5e ,ca9ozoic or ,plioc5e ,t]ti>y ,mioc5e ,oligoc5e ,eoc5e ,cretace\s ,mesozoic or ,jurassic ,second>y ,triassic ,p]mian ,p]mo-,c>bonif]\s ,c>bonif]\s ,palozoic ,devonian ,silurian ,ordovician ,cambrian4 ,precambrian4 ,a few rem>ks may be giv5 z to ! reason = adopt+ ?is classification4 ,x is n = a mom5t sugge/$ t ! ,sy/ems h ! same value1 if ! "t tak5 = _! accumulation be alone consid]$4 ,! b$s classifi$ z ,rec5t1 = example1 7 probably accumulat$ dur+ a lapse ( "t f> %ort] ?an t occupi$ = ! deposit ( "s ( ! s]ies or ev5 /ages ( a sy/em l ! ,silurian1 b ! rec5t rocks acquire a special significance f ! fact t we are liv+ 9 ! p]iod1 & ! ,ca9ozoic rocks z a :ole are capable ( great] subdivision ?an ! e>li] gr\ps1 on acc\nt ( ! great] ease ) :i* !y c be /udi$1 ow+ to ! small am\nt ( di/urbance :i* !y h usually und]gone :5 comp>$ ) t :i* has affect$ old] rocks1 & ! clos] resemblance ( _! faunas & floras to ^? ( exi/+ times4 ,) ref]5ce to ! gr\ps1 ! writ] has already comm5t$ ^u ! use ( ! t]ms ,palozoic1 ,mesozoic & ,ca9ozoic2 bel[ ! l[e/ ,palozoic rocks 7^? ( ! ,cambrian sy/em7 lie a gr\p ( rocks :i* h be5 v>i\sly spok5 ( z ,azoic1 ,eozoic1 & ,ar*an4 ,!re is an objection to ! use ( any "o ( ^! words 9 ?is s5se2 ! objection 9 ! case ( ! fir/ two is t ! t]m is !oretical & probably incorrect1 :il/ ! ^w ,ar*an1 o!rwise suitable1 has also be5 us$ 9 a m re/rict$ s5se4 ,9 ^! circum/ances ! t]m ,precambrian w be us$ :5 ref]r+ to any rocks :i* 7 =m$ bel[ ,palozoic times1 ?\gh no d\bt :5 ?is obscure gr\p ( rocks is m ?or\ghly und]/ood a satisfactory classification w be appli$ to x4 ,tak+ ! o!r gr\ps into acc\nt1 ! l[] sy/ems ( ! ,palozoic gr\p w be f\nd to v>y greatly accord+ to ! views ( diff]5t writ]s2 "s make only "o sy/em1 ! ,silurian1 o!rs two1 ! ,cambrian & ,silurian4 ,! ?ree sy/ems are "h adopt$1 n only because ! "o1 ,silurian1 is too unwieldy on acc\nt ( its size & requires subdivision 7& ! ,cambrian & ,silurian h[ev] def9$1 w be f\nd to be ( v unequal importance1 :]eas ! ?ree sy/ems adopt$ are ( fairly equal value71 b especially because :5 ! t]m ,ordovician is us$1 ! significance ( ! o!r t]ms ,cambrian & ,silurian is at once und]/ood4 ,an attempt has be5 made to %ew t ! ,devonian sy/em is non-exi/5t1 b ! result ( mod]n rese>* is to %ew t ! rocks plac$ 9 ?is sy/em are wor?y ( ! di/9ction1 bo? f _! importance & f ! di/9ctness ( ! fauna f ^? ( ! und]ly+ & ov]ly+ sy/ems4 ,! ,p]mo-,c>bonif]\s sy/em is adopt$1 because an important gr\p ( deposits has rec5tly be5 br\ght to light :i* 7 n repres5t$ ei!r 9 ! ,p]mian or ,c>bonif]\s sy/em z orig9ally def9$4 ,"s au?ors h advocat$ ! union ( ! ,p]mian & ,triassic sy/ems into "o sy/em plac$ at ! base ( ! ,mesozoic gr\p4 ,?is is unnecess>y1 & w\ld dep>t f ! classification orig9ally propos$1 :i* is to be deprecat$1 unless !re is any /rong reason = x4 ,! ,mesozoic sy/ems are classifi$ accord+ to ! me?od g5]ally adopt$4 ,7 a fre% classification to be propos$1 a portion ( ! ,cretace\s sy/em might be includ$ ) ! ,jurassic rocks1 b x is bett] to adh]e to ! old classification4 ,! divisions ( ! ,ca9ozoic rocks are h>dly sy/ems 9 ! s5se 9 :i* ! t]m is us$ 9 ! case ( ! old] rocks1 b ! reason = us+ ^! small] subdivisions has already be5 m5tion$4 ,! addition ( ! ,oligoc5e to ! orig9al divisions sugge/$ by ,lyell has be5 f\nd useful1 & ! t]m w be us$ 9 ?is "w4 ,! reasons = ! adoption ( ! p>ticul> m9or subdivisions 7s]ies & /ages7 9 ! foll[+ *apt]s w frequ5tly appe> :5 ! rocks ( ! v>i\s sy/ems are describ$1 & ne$ n be fur!r allud$ to 9 ?is place4 ,al?\gh mo/ geologi/s describe ! /ratifi$ rocks 9 asc5d+ sequ5ce beg9n+ ) ! olde/1 & proce$+ t[>ds ! newe/1 o!rs1 & notably ,lyell1 adopt$ ! opposite me?od & comm5c$ ) an acc\nt ( ! newe/ b$s4 ,! argum5t g5]ally us$ = ! latt] me?od is t x is easi] to "w f ! /udy ( ! kn[n to t ( ! less kn[n1 & z ! faunas ( ! newe/ rocks are mo/ l ! exi/+ faunas1 ! /ud5t w\ld m readily foll[ a description ( ! rocks 9 ! ord] :i* is opposite to t 9 :i* !y 7 deposit$4 ,9 practice1 ! /udy ( ! s$im5ts 9 _! prop] ord]1 t is1 9 ! ord] ( deposit1 w n be f\nd to task ! /ud5t to any great ext5t1 especially if1 z is v desirable1 he has /udi$ ! ma9 facts & pr9ciples ( ,palontology be=e comm5c+ ! /udy ( ! rock-sy/ems 9 detail4 ,!re is "o reason = beg9n+ ) ! /udy ( ! old] s$im5ts :i* outweighs any reasons :i* c be advanc$ aga9/ x1 namely t ! ev5ts ( any p]iod produce _! effect n only ^u ! /rata ( t p]iod1 b also on ^? ( succe$+ p]iods4 ,! task ( ! /ratigraphical geologi/ is really to le>n ! evolution ( ! e>?1 9 its *anges f ! simple to ! m complex conditions1 & x is q obvi\s t x is unnatural to attempt any /udy ( evolution by work+ backw>d4 ,= ?is reason ! /udy ( ! s$im5ts w be "h made 9 ! ord] :i* is usually adopt$1 by pass+ f ! old] to ! new]1 & f ! simple to ! m complex4 ,! ,briti% /rata w be ma9ly consid]$1 ?\gh ref]5ces w frequ5tly be made to _! =eign equival5ts1 & a full] acc\nt ( ! latt] w be add$ :5 ! ,briti% /rata are abnormal1 z are ^? ( ,triassic times1 & also :5 a p]iod is n repres5t$ among/ ! /rata ( ! ,briti% ,isles1 z = in/ance1 ! ,p]mo-,c>bonif]\s & ,mioc5e p]iods4 ,! /ud5t is recomm5d$ to ref] con/antly to good geological maps ( ! ,briti% ,isles1 ( ,europe1 & ( ! _w4 ,( maps ( ! ,briti% ,isles1 m5tion may be made ( ,sir ,a4 ,ramsay's geological map ( ,engl&1 ,sir ,a4 ,geikie's map ( ,scotl&1 & 8 map ( ! ,briti% ,isles1 ,j4 ,g4 ,good*ild's map ( ,engl& & ,wales1 a map ( ,europe by ,w4 ,topley & "o ( ! _w r$uc$ f t by ,j4 ,m>c\1 accompany+ ! fir/ & second volumes ( ! late ,sir ,j4 ,pre/wi*'s ,geology4 ,= special purposes m detail$ maps w be /udi$1 includ+ ! "o-in* maps ( ,h4 ,m4 ,geological ,survey1 & ! index map on a small] scale4 ,la/ly1 = an acc\nt ( ,briti% ,geology1 ref]5ce mu/ be made to ,h4 ,b4 ,woodw>d's ,geology ( ,engl& & ,wales1 :]e ! ,briti% =mations are describ$ 9 ord]1 & to ,w4 ,j4 ,h>rison's ,geology ( ! ,c\nties ( ,engl& & ,wales1 :]e ! /ratigraphical geology ( ! c\ntry is giv5 "u ! head ( ! diff]5t c\nties1 :i* are tak5 9 alphabetical ord]4 ,9 conclud+ ?is *apt]1 x is h>dly necess>y to say t e opportunity ( /udy+ ! *>act]s ( ! deposits & _! fossils 9 ! field %\ld be eag]ly seiz$1 & t mu* in=mation may be acquir$ ev5 on a railway j\rney1 especially z to ! influ5ce :i* ! deposits ex]t ^u ! sc5]y ( a region#dg4 ,footnote #dg3 ,9 ! fir/ edition ( ,h4 ,b4 ,woodw>d's ,geology ( ,engl& & ,wales1 an acc\nt ( ! geology ( ! ma9 l9es ( ,engli% railways is giv51 :i* is omitt$ 9 ! lat] edition4 ,x is well wor? consult+ by ^? :o take a long j\rney1 & x w be f\nd useful to take a geological map ) "o on ! j\rney s z to discov] :5 "o is pass+ f "o =mation to ano!r4 ,,*apt] ,,xii4 ,,! ,,precambrian ,,rocks4 ,/udy ( a geological map ( ! _w w %ew t ext5sive regions1 su* z p>ts ( ,sc&9avia1 _m tracts ( ,c5tral ,europe1 a l>ge area 9 ,canada1 & a consid]able portion ( ,brazil & ! adjo9+ c\ntries are occupi$ by cry/all9e s*i/s1 :i* und]lie ! olde/ kn[n s$im5t>y /rata 9 ^? places4 ,^! cry/all9e s*i/s =m ! floor ^u :i* ! s$im5ts con/itut+ ! bulk ( ! geological column re/1 & x is necess>y t we %\ld "k some?+ ( ! "* ( ?is floor4 ,o!r rocks :i* c be def9itely prov$ to be ( ,precambrian age are (t5 f\nd associat$ ) ! cry/all9e s*i/s1 & ^! associat$ rocks h (t5 und]gone m or less alt]ation subsequ5tly to _! =mation4 ,! diff]5ce betwe5 ! co>s] types ( cry/all9e s*i/s & ^! associat$ rocks is sometimes s m>k$ t geologi/s h necess>ily paid att5tion to x1 & sep>at$ ! two gr\ps ( rocks2 ! t]m ,ar*an has be5 us$ by "s geologi/s to include ! cry/all9e s*i/s1 & ,ep>*an = ! associat$ rocks ( kn[n ,precambrian age1 b ?\gh ?is sep>ation may sometimes be effect$1 !re are cases :5 x is impossible to draw any %>p l9e ( dem>cation betwe5 ',ar*an' & ',ep>*an' types4 ,9 ! pres5t /ate ( our k1 a *ronological classification ( ! ,precambrian rocks :5 appli$ to wide & di/ant regions is de/9$ to break d[n1 & x w be conv5i5t if we consid] at "s l5g? ! features ( ! ,precambrian rocks ( a p>ticul> region1 & apply ! k ?us ga9$ to a /udy ( ,precambrian rocks ( o!r areas1 & to a consid]ation ( our k ( ! ,precambrian rocks z a :ole4 ,9 do+ s1 ! t]m 'cry/all9e s*i/s' w be us$ some:at vaguely ) ref]5ce to a complex ( s*i/ose rocks ( :i* ! mode ( orig9 _c be fully det]m9$4 ,we may take our own c\ntry z a region :]e a good developm5t ( ! ,precambrian rocks occurs4 ,a few explanatory rem>ks conc]n+ ! mode ( detection ( ,precambrian rocks may n be amiss4 ,if any true organisms h be5 hi!rto discov]$ among/ ! rocks =m$ be=e ,cambrian times !y are valueless z a means ( correlat+ rocks1 & accord+ly li?ological *>act]s only are available 9 attempt+ to correlate ! rocks ( "o area ) ^? ( ano!r4 ,^? :o h read ! prec$+ *apt]s w h ga!r$ t comp>isons f\nd$ on simil>ity ( li?ological "* are n s valuable z ^? made aft] c>eful scrut9y ( ! fossils ( /rata1 b !y are by no means valueless1 & :5 ! rocks ( two areas :i* are n f> di/ant f "o ano!r pres5t close li?ological resemblances1 _! g5]al contemporaneity may be inf]r$ ) "s degree ( c]ta9ty4 ,x is only :5 we get ! l[e/ ,cambrian /rata ov]ly+ e>li] rocks t we h absolute pro( ( ! ,precambrian age ( ! latt]1 & x is necess>y1 !re=e1 t we %\ld h "s def9ite l[] limit to ! rocks ( ! ,cambrian sy/em4 ,x is n[ g5]ally agre$ t t limit %all be drawn at ! base ( a gr\p ( rocks conta9+ :at is kn[n z ! ,ol5ellus-fauna1 :i* w be consid]$ at great] l5g? 9 ! next *apt]1 & x w be well1 if ! t]m ,cambrian be n 9 future appli$ to any rocks b5ea? ! ones conta9+ ! relics ( ?is fauna1 = o!rwise !re is dang] ( ! indef9ite d[nw>d ext5sion ( ! ,cambrian sy/em4 ,we ne$ n be surpris$ to f9d great ?icknesses ( rock bel[ ! rocks conta9+ ! ,ol5ellus-fauna1 & pass+ upw>ds ) complete con=mity into ^? rocks2 nev]!less1 if x c be %ewn t ! ,ol5ellus-fauna _h n appe>$ dur+ ! deposition ( ! und]ly+ gr\p1 ! rocks ( t gr\p %\ld be t]m$ ,precambrian4 ,a case ( ?is nature has n yet be5 detect$ 9 our area1 & all ! rocks :i* h be5 prov$ to be ,precambrian 9 ,brita9 are sep>at$ f ! ov]ly+ ,cambrian rocks by a physical break1 ?\gh t break is n necess>ily v l>ge1 & 9 "s di/ricts is probably ( little importance4 ,hi!rto ! ,ol5ellus-fauna has be5 detect$ 9 ,ross1 ,w>wick%ire1 ,%rop%ire1 ,worce/]%ire & probably 9 ,pembroke%ire1 & ! rocks und]ly+ ! ,ol5ellus-b$s 9 ^? c\nties c be prov$ to be ,precambrian 7i4e4 if ! ,ol5ellus-age ( ! ,pembroke%ire rocks be ultimately e/abli%$1 & ! rese>*es ( ,dr ,hicks t5d to prove t x w almo/ c]ta9ly be done74 ,x w be conv5i5t if we take ! in/ances :]e ! age ( ! rocks c be prov$ ) c]ta9ty or ) a consid]able degree ( probability fir/1 & !n consid] ! examples ( rocks :i* are f\nd bel[ ,cambrian /rata1 ?\gh ^! h n hi!rto yield$ ! ,ol5ellus-fauna1 conclud+ ) a notice ( rocks :i* h be5 claim$ to be ( ,precambrian age on acc\nt ( _! li?ological *>act]s1 ?\gh !y are n n[ se5 to be imm$iately succe$$ by /rata app]ta9+ to ! ,cambrian sy/em4 ,comm5c+ ) ! region :]e we h ! greate/ developm5t ( ! kn[n ,precambrian rocks1 namely ,ross1 ,su!rl& & ! ,hebrides1 we may expla9 ! g5]al relation%ip ( ! rocks by means ( a g5]alis$ section 7fig4 #ae74 ,illu/ration3 ,fig4 #ae4 ,! l[e/ rocks a are cry/all9e s*i/s1 !y are succe$$ by a set ( ar5ace\s rocks b kn[n z ! ,torridonian b$s1 :i* re/ uncon=mably ^u ! upturn$ edges ( ! cry/all9e s*i/s1 :il/ ! ,cambrian rocks1 c1 re/ ) ano!r uncon=mity sometimes ^u ! p>tly d5ud$ ,torridonian b$s1 or :]e ! latt] h be5 completely remov$1 z on ! "r side ( ! figure1 directly ^u ! cry/all9e s*i/s1 ?us pres5t+ an example ( uncon=mable ov]lap4 ,! occurr5ce ( ! ,ol5ellus-fauna 9 ! basem5t b$s ( ! ,cambrian sy/em ne> ,lo* ,m>ee1 proves ! ,precambrian age ( ! ,torridonian /rata1 :il/ ! uncon=mable junction betwe5 ! latt] & ! cry/all9e s*i/s indicates t we are "h deal+ ) two di/9ct sets ( ,precambrian rocks1 "o ( ,ep>*an & ! o!r ( ,ar*an type4 ,! cry/all9e s*i/s consi/ ( rocks ( v v>i$ li?ological *>act]s1 "s ) gneissose1 & o!rs ) s*i/ose /ructure1 & !y v>y 9 degree ( acidity f ultrabasic rocks to ^? ( acid composition4 ,mo/ ( !m exhibit p>allel /ructures1 :i* 9 _m cases c be %ewn to h be5 impress$ on ! rocks subsequ5tly to _! consolidation1 ?\gh ?is ne$ n h occurr$ & probably did n occur ) "s ( !m1 especially ! granitoid gneisses4 ,! rese>*es ( ! memb]s ( ,h4 ,m4 ,geological ,survey h %ewn t _m ( ^! rocks 7 orig9ally intrusive igne\s rocks1 ?\gh x is n yet kn[n into :at rocks ^? :i* 7 fir/ consolidat$ 7 inject$1 & ! orig9 ( ! bulk ( ! s*i/s /ill rema9s to be elucidat$4 ,subsequ5tly to _! consolidation & be=e ! deposition ( ! e>lie/ ,torridonian rocks !y 7 subject$ to m ?an "o set ( e>?-movem5ts1 :i* fold$ !m & impress$ a s]ies ( p>allel /ructures ^u _m ( !m2 & accord+ly we f9d t ! pebbles ( ! cry/all9e s*i/s :i* are f\nd among/ ! basal conglom]ates ( ! ,torridonian rocks consi/ ( fragm5ts :i* _h und]gone ! alt]ation caus$ by ^! e>?-movem5ts be=e !y 7 d5ud$ f _! p>5t-rocks#dh4 ,footnote #dh3 ,= an acc\nt ( ^! rocks1 _! *>act]s1 & ! effects ( e>? movem5t ^u !m1 ! read] %\ld consult a ,report on ! ,rec5t ,"w ( ! ,geological ,survey 9 ! ,nor?-,we/ ,highl&s ( ,scotl&3 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xliv4 p4 #cgh4 ,! ,torridonian sy/em is compos$ ( rocks :i* are l>gely ( ar5ace\s "*1 ! mo/ prom95t b$s be+ =m$ ( r$ s&/ones1 & ! bulk ( ! fragm5ts 9 !m h cle>ly be5 d]iv$ by d5udation f ! cry/all9e s*i/s1 _m ( ! b$s be+ compos$ ( arkose1 :]e ! qu>tz is mix$ ) a l>ge proportion ( felsp> & (t5 ( f]ro-magnesian m9]als4 ,! deposits are cle>ly s$im5t>y1 & are z little alt]$ z _m /rata ( mu* m rec5t orig91 only possess+ /ructures produc$ by metamorphic action "u exceptional circum/ances4 ,! detail$ rese>*es ( ! geological surveyors prove t ! rocks ( ?is sy/em h a mu* great] ?ickness & are ( m v>i$ li?ological *>act]s ?an 0 previ\sly suppos$4 ,! total ?ickness ( ! /rata is ov] #aj1jjj feet1 & ! s&/ones are associat$ ) deposits ( a muddy "*1 & ) occasional b&s ( lime/one2 9 ^! circum/ances ! discov]y ( fossils w\ld excite no surprise1 & 9 #ahia ,sir ,a4 ,geikie ann\nc$ ! detection ( traces ( annelids & "s m obscure rema9s ( o!r organisms 9 ^! /rata1 :i* h n yet be5 describ$#di4 ,^! ,torridonian /rata furni% u ) ! mo/ satisfactory gr\p ( ,precambrian s$im5ts yet detect$ 9 ,brita9#ej4 ,footnote #di3 ,an acc\nt ( ! subdivisions & li?ological *>act]s ( ! rocks ( ! ,torridonian ,sy/em w be f\nd 9 ! ,annual ,report ( ! ,geological ,survey ( ! ,unit$ ,k+dom = #ahic4 ,footnote #ej3 ,x has be5 rec5tly ma9ta9$ t "s ( ! ,torridonian rocks are ( olian orig94 ,9 ! s\?-ea/ ,highl&s is a great mass ( cry/all9e s*i/s ( a less gneissose "* ?an t ( ! nor?-we/1 to :i* ,sir ,a4 ,geikie has appli$ ! "n ,dalradian4 ,_m ( ^! s*i/s w be f\nd by exam9ation ( ! geological map ( ,scotl& to be sep>able into divisions1 :i* by means ( _! li?ological *>act]s c be trac$ long di/ances across ! c\ntry1 & !y pres5t all ! *>act]s ( s$im5t>y rocks1 ?\gh !y are associat$ ) intrusive igne\s rocks1 & h und]gone great metamorphic *anges s9ce _! =mation4 ,cambrian rocks h n yet be5 discov]$ imm$iately above !m1 ?\gh !y are cle>ly old] ?an ,ordovician times1 b ! exi/5ce ( rocks associat$ ) !m along _! nor?-we/ bord]s1 :i* 9 li?ological *>act]s closely resemble "s ( ! rocks ( ! cry/all9e s*i/s ( ! nor?-we/ ,highl&s1 indicates ! probability ( _! g5]al ,precambrian age4 ,9 "s in/ances1 ! extreme types ( metamorphism :i* !y exhibit are ! result ( ! k9d ( action usually t]m$ pyrometamorphic z has be5 %ewn by ,mr ,g4 ,b>r[#ea4 ,footnote #ea3 ,b>r[1 ,g4 ,on an ,intrusion ( ,muscovite-biotite gneiss 9 ! ,s4,e4 ,highl&s ( ,scotl&1 & its accompany+ metamorphism4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlix4 p4 #ccj4 ,9 ,engl& & ,wales ! rocks :i* h be5 %ewn or inf]r$ to be ,precambrian1 :5 n intrusive1 are l>gely ( volcanic orig94 ,! mo/ satisfactory example ( ! occurr5ce ( ! ,ol5ellus-fauna is t ( ! ,cambrian ,comley s&/one ( ,%rop%ire1 :i* re/s uncon=mably ^u a set ( rocks t]m$ by ,dr ,callaway ! ,uriconian rocks2 ! latt] are ess5tially volcanic1 & /rongly resemble ,precambrian rocks ( o!r ,briti% areas4 ,!re is also /rong reason to suppose t ! s$im5ts to :i* ! "n ,longmyndian has be5 appli$1 :i* h be5 describ$ by ! ,rev4 ,j4 ,f4 ,blake1 are ( ,precambrian age1 =1 z ,pr(essor ,lapwor? has po9t$ out1 ! ?ree great subdivisions ( ! ,cambrian sy/em are pres5t 9 ! area "u consid]ation1 & ! rocks ( ea* are entirely diff]5t f ^? ( ! adjo9+ ,longmynd area4 ,9 ,%rop%ire !re=e we meet ) "o set ( volcanic rocks1 & ano!r set consi/+ ( s$im5t>y rocks1 ( :i* ! =m] is c]ta9ly1 ! latt] almo/ c]ta9ly ( ,precambrian age1 & z ! ,longmyndian rocks are 9 a comp>atively unalt]$ condition1 consi/+ ( normal s$im5ts1 we may well expect ! discov]y ( fossils 9 !m also#eb4 ,! ,ol5ellus-fauna has be5 f\nd ne> ,nuneaton 9 ,w>wick%ire 9 b$s :i* uncon=mably succe$ volcanic rocks1 ! ,caldecote s]ies ( ,pr(4 ,lapwor?1 & ! latt] are !re=e ( ,precambrian age#ec4 ,a few fossils belong+ to ! ,ol5ellus-fauna h occurr$ 9 ! olde/ ,cambrian rocks ( ! ,malv]n di/rict1 & ^! rocks re/ uncon=mably ^u ^? ( an old ridge :i* is !re=e compos$ ( ,precambrian rocks4 ,! rocks ( ?is ridge are l>gely ( intrusive igne\s orig91 ?\gh p>allel /ructures h be5 impress$ ^u !m z ! result ( subsequ5t de=mation1 b "s ( ! rocks are almo/ c]ta9ly ( contemporane\s volcanic orig9#ed4 ,9 ! ,wrek9 ridge1 igne\s & pyrocla/ic rocks are f\nd succe$$ uncon=mably by ,cambrian rocks :i* resemble ^? ( ! ,malv]n & ,nuneaton di/ricts1 & probably belong to ! p]iod ( exi/5ce ( ! ,ol5ellus-fauna1 & ^! igne\s & pyrocla/ic rocks are presumably ( ,precambrian age1 & ! contemporane\s rocks con/itute ,dr ,callaway's typical ,uriconian gr\p4 ,volcanic a%es & breccias are accompani$ by devitrifi$ pit*/ones & intrud$ granitic rocks1 :i* may or may n be all ( ! same g5]al age#ee4 ,! rocks :i* h be5 claim$ z ,precambrian 9 ,pembroke%ire & 9 ,ca]n>von%ire h ! same g5]al *>act]s z ^? ( ! ,wrek9 ridge4 ,pyrocla/ic rocks und]lie ! olde/ ,cambrian rocks1 ) discordance betwe5 ! two1 & associat$ ) ^! pyrocla/ic rocks are qu>tz felsites :i* accord+ to "s are ( contemporane\s nature :il/ o!rs ma9ta9 _! intrusive orig94 ,9 ea* c\nty granites are f\nd :i* are n[ g5]ally recognis$ to be intrusive1 ?\gh !re seems to be no d\bt z to _! be+ ( ! same g5]al age z ! rocks ) :i* !y are associat$1 & !re=e presumably ,precambrian4 ,! ,pembroke%ire rocks are m>k$ by ! occurr5ce ( a c]ta9 am\nt ( metamorphism1 probably ( m ?an "o k9d1 :i* has conv]t$ pyrocla/ic volcanic rocks into s]icitic-s*i/s & qu>tz-felsites into hllefl9tas#ef4 ,! t]m ,pebidian giv5 by ,dr ,hicks to ! contemporane\s volcanic fragm5tal rocks %\ld be reta9$1 & if ^! rocks be ev5tually %ewn to be contemporane\s ) simil> volcanic rocks ( o!r di/ricts1 may be appli$ g5]ally1 z x has priority ov] o!r t]ms z ,uriconian & ,caldecote s]ies4 ,! t]m ,dimetian 0 appli$ to rocks kn[n to be intrusive1 & mu/ be dropp$ z a *ronological t]m1 :il/ ! exi/5ce ( an ,arvonian sy/em sep>ate f ! ,pebidian sy/em is n fully prov$4 ,footnote #eb3 ,! read] may consult a pap] by ,pr(4 ,lapwor? ,on ,ol5ellus ,callavei & its geological relation%ips1 ,geol4 ,mag4 ,dec ,,iii4 vol4 ,,viii4 p4 #ebi1 = in=mation conc]n+ ! relation%ip ( ! ,ol5ellus b$s ( ,%rop%ire to ! m anci5t rocks2 ! ,uriconian rocks are describ$ by ,dr ,callaway 9 a s]ies ( pap]s1 especially 9 ! ,qu>t]ly ,j\rnal ( ! ,geological ,society1 vol4 ,,xxxv4 p4 #fdc1 vol4 ,,xxxviii4 p4 #aai1 vol4 ,,xlii4 p4 #dha & vol4 ,,xlvii4 p4 #aji1 :il/ ! li?ological *>act]s ( ! ,longmyndian rocks are describ$ by ! ,rev4 ,j4 ,f4 ,blake 7,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlvi4 p4 #chf74 ,footnote #ec3 ,see ,lapwor?1 ,c41 ,on ! sequ5ce & sy/ematic position ( ! ,cambrian rocks ( ,nuneaton1 ,geol4 ,mag4 ,dec ,,iii4 vol4 ,,iii4 p4 #cai2 & ,wall]1 ,t4 ,h41 ,prelim9>y ,note on ! ,volcanic & ,associat$ ,rocks ( ! neighb\rhood ( ,nuneaton1 ibid4 p4 #cbb4 ,footnote #ed3 ,= details conc]n+ ! rocks ( ! ,malv]n ,hills see pap]s by ,callaway 9 ! ,qu>t]ly ,j\rnal ( ! ,geological ,society1 vol4 ,,xxxvi4 p4 #ecf1 ,,xliii4 p4 #ebe1 ,,xlv4 p4 #dge1 & ,,xlix4 p4 #cih1 & a pap] by ,pr(4 ,a4 ,h4 ,gre51 ibid4 vol4 ,,lvi4 p4 #a4 ,footnote #ee3 ,callaway1 ,c41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxv4 p4 #fdc4 ,footnote #ef3 ,! ,pembroke%ire area is ( int]e/ z ! probable exi/5ce ( ,precambrian rocks 9 ,brita9 0 fir/ indicat$ on good evid5ce 9 ?is c\nty4 ,! g5]al /ructure ( ! di/rict is fairly simple1 consi/+ ( ,cambrian rocks b5ea? :i* ,precambrian rocks are expos$ 9 at lea/ two ridges ( :i* ! nor!rly & m important "o runs ?r\gh ,/ ,davids4 ,! rocks ( ! ,/ ,davids ridge consi/ ( a b9>y granite 7granitoidite71 felsites1 & volcanic a%es & breccias ( int]m$iate composition4 ,mu* div]sity ( op9ion has exi/$1 & to "s ext5t /ill exi/s z to que/ions ( detail1 & a v ext5sive lit]ature has be5 devot$ to ^! rocks4 ,among/ ! num]\s pap]s :i* treat ( !m1 ! /ud5t may consult ! foll[+3--,hicks1 ,h41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxiii4 p4 #bbi1 ,,xxxiv4 p4 #adg1 ,,xxxv4 p4 #bhe1 ,,xl4 p4 #ejg1 ,,xlii4 p4 #cea1 ,geikie1 ,a41 ibid4 vol4 ,,xxxiv4 p4 #bfa1 ,blake1 ,j4 ,f41 ibid4 vol4 ,,xl4 p4 #bid1 & ,morgan1 ,c4 ,ll41 ibid4 vol4 ,,xlvi4 p4 #bda4 ,mu* ( ! matt] conta9$ 9 ^! pap]s is controv]sial1 & ne$ n be fully read by ^? :o m]ely wi% to obta9 a g5]al acc\nt ( ! rocks ( ! di/rict4 ,9 ,ca]n>von%ire two ridges are f\nd1 ! "o runn+ f ,bangor to ,ca]n>von1 & ! o!r ?r\gh ,llanb]is lake4 ,! rocks ( ^! are g5]ally simil> to ^? ( ,/ ,davids1 & z ! l[e/ ,cambrian rocks ( ! area closely resemble ^? ( ,/ ,davids1 ! ,precambrian age ( ! rocks ( ^! ridges is r5d]$ highly probable1 ?\gh until ! discov]y ( ! ,ol5ellus-fauna 9 ! area1 x _c be reg>d$ z prov$#eg4 ,footnote #eg3 ,^! rocks are describ$ by ,t4 ,mc,k4 ,hughes1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxiv4 p4 #acg1 & ,,xxxv4 p4 #fhb2 by ,pr(4 ,t4 ,g4 ,bonney1 ibid4 vol4 ,,xxxiv4 p4 #add2 & by ,dr ,hicks1 ibid4 vol4 ,,xxxv4 p4 #bie4 ,! actual position ( ! simil> rocks ( ,anglesey has n be5 s cle>ly fix$1 z ! rocks associat$ ) !m are ( ,ordovician age1 b _! resemblance to ! rocks ( ! adjo9+ regions r5d]s _! ,precambrian age highly probable4 ,x is int]e/+ to f9d 9 association ) ! rocks :i* resemble ^? ( ,ca]n>von%ire1 o!rs :i* ,sir ,a4 ,geikie recognises z q simil> to "s exi/+ among/ ! cry/all9e s*i/s ( ! nor?-we/ ,highl&s ( ,scotl&1 & :5 ^! anci5t rocks ( ,anglesey h be5 mapp$ 9 detail1 !y w probably be f\nd to pres5t great] v>iety ?an is af=d$ by any ,precambrian rocks ( ,great ,brita9 occurr+ ,s4 ( ! ,scot* bord]#eh4 ,footnote #eh3 ,pap]s ^u ! old rocks ( ,anglesey w be f\nd 9 _m volumes ( ! ,qu>t]ly ,j\rnal ( ! ,geological ,society2 see especially ,hicks1 vol4 ,,xxxv4 p4 #bie1 ,callaway1 vol4 ,,xxxvi4 p4 #ecf1 ,,xxxvii4 p4 #baj1 & ,blake1 ,,xliv4 p4 #dfc4 ,( rocks ^: age is m unc]ta91 b :i* are probably ( ,precambrian age1 ^? ( ,*>nwood ,=e/ 9 ,leice/]%ire may fir/ be notic$4 ,!y are l>gely ( pyrocla/ic orig91 & f _! lik5ess to simil> rocks ( prov$ ,precambrian age1 !y are v probably ( ?is age1 z sugge/$ by ,messrs ,hill & ,bonney#ei4 ,a gr\p ( cry/all9e s*i/s is f\nd 9 ! s\? ( ,cornwall1 especially ne> ! ,liz>d1 & simil> rocks are f\nd 9 ! ,*annel ,isles4 ,z _! relation%ip to new] rocks is n cle>1 little c be said ab\t !m1 :i* has n already be5 notic$ 9 m5tion+ ! cry/all9e s*i/s ( o!r regions#fj4 ,footnote #ei3 ,hill & ,bonney1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxiii4 p4 #ged1 ,,xxxiv4 p4 #aii & ,,xlvii4 p4 #gh2 see also ,watts1 ,w4 ,w41 ,rep4 ,brit4 ,assoc4 = #ahif1 p4 #gie4 ,footnote #fj3 ,= an acc\nt ( ! ,volcanic ,hi/ory ( ,brita9 9 ,precambrian times1 see ,sir ,a4 ,geikie1 ,presid5tial ,address to ! ,geological ,society1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlvii4 p4 #fc4 ,! ,precambrian rocks ( ! ,european cont95t consi/ l>gely ( cry/all9e s*i/s :i* 9 _! g5]al aspects recall ^? ( ! nor?-we/ ,highl&s ( ,scotl&4 ,important masses are f\nd 9 ,bav>ia1 ,bohemia1 ,france1 ,spa91 ,sc&9avia & ,russia4 ,! ,sc&9avian & ,russian rocks ( ,ar*an type are 9 places succe$$ by ! ,ol5ellus-be>+ b$s ( ! ,cambrian rocks1 & rocks ( ,ep>*an "* are n ext5sively develop$1 ?\gh c]ta9 ,norwegian rocks may be ! equival5ts ( ! ,torridonian rocks ( ,scotl&1 & o!r rocks ( ?is type are f\nd 9 places 9 ,sw$54 ,9 ,bohemia & 9 ,brittany ,precambrian /rata ( ,ep>*an type h be5 discov]$1 & ?is type probably occurs else:]e 9 ,europe4 ,! ,nor? ,am]ican rocks require "s notice1 = x 0 9 ,canada t ! exi/5ce ( ,precambrian rocks 0 fir/ recognis$1 & ! t]m ,laur5tian1 orig9ally appli$ to an ,ar*an type ( ,precambrian rocks 9 ,canada1 0 subsequ5tly adopt$ 9 speak+ ( _m ,precambrian rocks else:]e1 ?\gh x is n[ wisely re/rict$ to ! type ( rock 9 ! orig9al area to :i* ! "n 0 fir/ giv54 ,^! ,laur5tian rocks acquir$ a special1 int]e/ on acc\nt ( ! occurr5ce 9 _! lime/ones ( a suppos$ reef-build+ =am9if]1 ,eozoon canad5se1 b detail$ /udy ( its /ructure & mode ( occurr5ce has conv9c$ mo/ geologi/s t ! /ructure is inorganic4 ,! ,laur5tian rocks ( ! typical ,laur5tide region are l>gely cry/all9e s*i/s associat$ ) massive cry/all9e rocks4 ,! attempt to sep>ate !m *ronologically into a ,l[] & ,upp] division 0 premature1 z %ewn by ! fact t _m ( !m1 ^u detail$ /udy1 prove to be intrusive igne\s rocks4 ,9 ! neighb\rhood ( ,lake ,huron1 a set ( s$im5t>y rocks ov]ly+ ! ,ar*an rocks is ( ,ep>*an type1 consi/+ to a great ext5t ( volcanic rocks1 clay-slates & s*i/s ) intrusive igne\s rocks2 x has be5 t]m$ ! ,huronian ,sy/em1 & ?is t]m has also be5 ext5sively appli$ to o!r ,ep>*an types f\nd else:]e1 b %\ld be re/rict$ to ! rocks ( ! ,huron di/rict4 ,a numb] ( o!r rocks ( ,ep>*an type h be5 discov]$ 9 v>i\s p>ts ( ,nor? ,am]ica1 & h be5 gr\p$ toge!r "u ! title ( ,algonkian1 a "n propos$ = !m by ,dr ,c4 ,d4 ,walcott1 & an attempt has be5 made to arrange !m 9 *ronological ord]1 ?\gh 9 ! abs5ce ( fossils1 ! rocks ( diff]5t di/ricts c only be s arrang$ by ref]5ce to li?ological *>act]s2 nev]!less a detail$ /udy ( ! ,ep>*an & "s ( ! m f9ely cry/all9e s*i/ose rocks po9ts to ! exi/5ce ( a numb] ( divisions ( s$im5t>y rocks ( ,precambrian age1 "s ( :i* may atta9 to ! dignity ( =m+ sep>ate sy/ems#fa4 ,by f> ! mo/ in/ructive developm5t ( ,am]ican ,precambrian rocks has be5 f\nd 9 ! ,ra9y ,lake region ( ,canada1 & x is ! subject ( a special memoir by ,dr ,a4 ,c4 ,lawson#fb4 ,! ,ar*an rocks ( ! region are divid$ into a l[] ,laur5tian & an upp] division1 :i* is fur!r subdivid$ into ! ,c\t*i*+ s]ies bel[ & ! ,keewat9 s]ies above1 ?\gh ! rocks ( ! ,keewat9 s]ies are l>gely ( ,ep>*an "*4 ,! ,laur5tian rocks ( ?is region resemble ^? ( ! ,laur5tide area1 & consi/ ( highly cry/all9e s*i/ose & gneissose rocks associat$ ) compact rocks4 ,! ,c\t*i*+ s]ies consi/s ( mica s*i/s & grey lam9at$ gneisses1 :i* appe> to h be5 ( s$im5t>y orig91 alt]$ by subsequ5t metamorphic action1 :ile ! ,keewat9 s]ies1 :i* reposes sometimes ^u ! rocks ( ! ,c\t*i*+ s]ies 7:5 ! junction is an uncon=mable "o71 sometimes ^u ! ,laur5tian rocks1 is =m$ ( pyrocla/ic rocks & lava fl[s ) int]calat$ s$im5t>y rocks2 "s ( ! ,keewat9 rocks are highly metamorphos$ b o!rs h und]gone little or no metamorphic *ange4 ,! mo/ important po9t 9 connexion ) ^! rocks ( ! ,ra9y ,lake ,region has ref]5ce to ! relation%ip betwe5 ! ,laur5tian rocks & ^? ( ! ,c\t*i*+ & ,keewat9 s]ies4 ,lawson demon/rates ! igne\s nature ( ! ,laur5tian rocks1 & br+s =w>d evid5ce ( v>i\s k9ds t !y 7 =m$ by ! fusion ( ! basem5t or floor ^u :i* ! =mations ( ! upp] division ( ! ,ar*an 7 orig9ally deposit$4 ,) ! fusion ( ?is floor x seems probable t portions ( ! sup]9cumb5t /rata1 :i* once =m$ integral p>ts ( ei!r ! ,c\t*i*+ s]ies or ! ,keewat91 h also be5 absorb$ into ! g5]al magma1 & reappe>$ on cry/allization z ,laur5tian gneiss4 ,?is fusion1 h[ev]1 only ext5d$ up to a c]ta9 unev5 surface1 :i* surface con/itutes ! dem>cation betwe5 ! pres5t upp] & l[] ,ar*an4 ,above ?is surface1 or upp] limit ( fusion1 ! =mation ( ! ,c\t*i*+ & ,keewat9 s]ies reta9$ _! /rati=m or b$d$ disposition1 & re/$ z a cru/ ( h>d & brittle rocks ^u ! magma1 subject to its metamorphos+ influ5ces#fc4 ,footnote #fa3 ,a l>ge numb] ( classifications h be5 propos$ = ! ,ar*an rocks ( ,am]ica2 ! mo/ plausible "o is giv5 9 ,sir ,a4 ,geikie's ,text ,book ( ,geology1 ,?ird ,edition1 p4 #gaf4 ,footnote #fb3 ,lawson1 ,a4 ,c41 ,report on ! ,geology ( ! ,ra9y ,lake ,region4 ,montreal1 #ahhh4 ,footnote #fc3 ,lawson1 op4 cit4 p4 #aci4 ,we may n[ pass briefly 9 review ! evid5ce :i* has be5 s f> obta9$ z to ! mode ( =mation ( ! v>i\s ,precambrian rocks4 ,! exi/5ce ( a v v>i$ fauna among/ ! e>lie/ ,cambrian /rata has be5 comm5t$ ^u by _m geologi/s1 & accord+ to accept$ explanations ( ! orig9 ( t fauna1 an enorm\s p]iod ( "t elaps$ be=e ! deposition ( ! e>lie/ ,cambrian /rata4 ,dur+ portions ( t long p]iod1 ! und\bt$ly cla/ic rocks ( ,ep>*an type 7 deposit$1 & probably _m o!rs :i* are n[ s alt]$ by metamorphism1 l "s ( ! ,c\t*i*+ rocks ( ,canada1 t _! orig9al cla/ic orig9 c only be inf]r$ & n directly prov$4 ,volcanic activity 0 v rife dur+ ! deposition ( "s ( ^! ,ep>*an rocks1 ?\gh p]haps n m s ?an dur+ ! =mation ( "s ( ! ,l[] ,palozoic ,rocks4 ,all attempts to prove ! occurr5ce ( organisms 9 ,precambrian /rata h hi!rto fail$1 = no und\bt$ fossil has be5 describ$ :i* is unhesitat+ly accept$ z ( ,precambrian age1 not)/&+ ! _m ass]t$ occurr5ces ( su* fossils4 ,t fossils w ev5tually be discov]$ is m ?an probable1 & _! non-detection at ! pres5t "t is 9 no way v surpris+1 :5 we rememb] ! long "t t elaps$ aft] ! exi/5ce ( /ratifi$ rocks bel[ ! ,upp] ,palozoic rocks _h be5 recognis$1 be=e def9ite faunas 7 discov]$ 9 !m4 ,! det]m9ation ( ! ,precambrian age ( /ratifi$ rocks is rec5t1 & n[ t ?is det]m9ation has be5 made1 ! se>* = fossils w be m eag]1 & is likely to be rew>d$ by _! discov]y4 ,fur!rmore1 exp]i5ce %[s t :5 fossils are discov]$ 9 rocks ( unkn[n age1 !re is a t5d5cy to ref] ^? rocks to "s kn[n p]iod1 & consequ5tly we may actually possess ,precambrian fossils1 out ( b$s :i* h be5 errone\sly ref]r$ to ! ,cambrian or a lat] p]iod4 ,ano!r important "q is t ( ! metamorphism ( a l>ge numb] ( ,precambrian rocks1 & "h aga9 rec5t rese>* t5ds to %[ t ! metamorphism is n ( a k9d diff]5t f t :i* occurr$ aft] ! end ( ,precambrian times2 ! discov]y ( cry/all9e s*i/s 9 ,norway1 ,kirkcudbright%ire & ,we/morl& among/ ,l[] ,palozoic rocks1 :i* resemble ^? ( ,ar*an masses 9 all respects except 9 ! ext5t ( area :i* !y cov]1 %[s t simil> processes to ^? :i* occurr$ 9 ,precambrian times w5t on dur+ lat] p]iods1 ?\gh p]haps n on s l>ge a scale4 ,! great ext5t ( ^! metamorphic rocks ( ,precambrian age c h>dly be due 9 any great degree to ! long] "t dur+ :i* !y h be5 subject$ to metamorphic influ5ce1 = !re is evid5ce t mu* ( ! *ange took place 9 ,precambrian times1 f> m ?an has occurr$ s9ce1 & x is a significant fact t ^! old rocks are m ext5sively p5etrat$ by intrusive igne\s masses ?an ^? ( lat] p]iods2 "h aga9 we f9d t mu* ( ! intrusion actually occurr$ 9 ,precambrian times4 ,! great] ext5t ( intrusion & metamorphism among/ ^! ,precambrian rocks ?an among/ lat] s$im5ts indicates "s diff]5ces ( conditions 9 ! case ( ,precambrian & lat] times4 ,if besides intrusion1 actual fusion ( floors ( ,precambrian rocks occurr$1 we may well suppose t ! e>li] records ( ! rocks are = ev] lo/ to u1 ! e>lie/ s$im5ts hav+ be5 fus$1 b t ! hi/ory ( life ^u our e>? is to be reveal$ to u fir/ 9 s late a /age z t ( ,cambrian times is highly improbable1 & we may look =w>d ) confid5ce to lay+ b>e ! records ( ! rocks compos+ ! geological column "s way bel[ ! ,cambrian portion ( ! column4 ,^u ?is f\ndation ( igne\s rock1 s$im5t & volcanic mat]ial1 =m$ 9 ,precambrian times1 ^: hi/ory we h only begun to /udy1 0 laid d[n ! great mass ( s$im5t :i* ! geologi/ has m completely /udi$1 :]e abundant traces ( life are pres]v$1 & conc]n+ ^: hi/ory we c ga9 a great] insight ?an is p]mitt$ u 9 ! case ( ! old ,f\ndation ,/ones4 ,,*apt] ,,xiii4 ,,cycles ,,( ,,*ange ,,9 ,,! ,,briti% ,,area4 ,be=e /udy+ 9 fur!r detail ! /rata ( ! geological column1 x w be conv5i5t to deal ) ! great physical *anges :i* h occurr$ 9 ! ,briti% area f ,precambrian times to ! pres5t day1 z ?is w cle> ! way = a "r appreciation ( ! ma9 v>iations 9 ! *>act]s & di/ribution ( ! /rata4 ,at ! end ( ,precambrian times !re 0 a g5]al upheaval ( ! ,briti% area1 & ?is we may speak ( z ! ,fir/ ,cont95tal ,p]iod4 ,x 0 foll[$ by depression & ext5sive s$im5tation1 proce$+ m or less cont9u\sly ?\gh ) local int]ruptions ?r\gh ,l[] ,palozoic times1 s t s f> z ,brita9 is conc]n$ we may speak ( ,l[] ,palozoic times z con/itut+ ! ,fir/ ,m>9e ,p]iod4 ,ext5sive upheaval gave rise to cont95tal tracts & m\nta9 *a9s1 & deposits ( abnormal "* 7z comp>$ ) ord9>y m>9e deposits7 at ! end ( ,l[] ,palozoic times2--! ,devonian p]iod 0 "o ( elevation & d5udation1 & we may !re=e ref] to x z ! ,second ,cont95tal ,p]iod4 ,?is 0 foll[$ by depression & s$im5tation 9 ,c>bonif]\s times1 & ^! ,c>bonif]\s times con/itute ! ,second ,m>9e ,p]iod4 ,elevation gave rise to cont95tal tracts & m\nta9 *a9s at ! end ( ,c>bonif]\s times1 & "h aga9 we f9d pro(s ( ext5sive d5udation & ! =mation ( abnormal deposits3--! ,p]mo-,triassic p]iod is ! ,?ird ,cont95tal ,p]iod4 ,depression set 9 dur+ e>ly ,jurassic times & cont9u$ ?r\gh\t ! ,mesozoic & ! e>ly "p ( ,t]ti>y times1 :i* =m ! ,?ird ,m>9e ,p]iod4 ,di/urbances culm9at+ 9 ,mioc5e times once m produc$ t]re/rial conditions4 ,9 ?is1 ! ,f\r? ,cont95tal ,p]iod1 we are /ill liv+4 ,f :at has be5 previ\sly writt5 x w be se5 t ea* ( ! m>9e p]iods %\ld be m>k$ by an e>ly & late %all[-wat] phase1 sep>at$ by an int]v5+ m>9e phase1 & ! importance ( ! phases w dep5d ^u ! l5g? ( "t dur+ :i* !y exi/$1 & w diff] m>k$ly 9 diff]5t cases1 :il/ ! di/9ctness ( ! middle phase f ! upp] & l[]1 w dep5d ^u ! magnitude ( ! maximum subm]g5ce4 ,dur+ ! fir/ m>9e p]iod subm]g5ce 0 comp>atively rapid1 & ! %all[-wat] phase only la/$ ?r\gh v e>ly ,cambrian times 9 mo/ regions1 :il/ ! deep-wat] phase1 complicat$ by _m m9or upheavals1 ext5d$ ?r\gh ! ma9 "p ( ,cambrian1 ,ordovician & ,silurian times1 & 0 replac$ by ! lat] %all[-wat] phase at ! end ( ,silurian times4 ,! second m>9e p]iod aga9 0 u%]$ 9 by rapid subm]g5ce1 s t ! %all[-wat] phase 0 brief1 & ! ma9 mass ( ! ,l[] ,c>bonif]\s /rata 0 deposit$ 9 deep wat]2 b1 unlike ! fir/ m>9e p]iod1 ! second 0 *>act]is$ by ! occurr5ce ( a long int]val ( "t m>k+ ! lat] %all[-wat] phase1 dur+ :i* ! :ole ( ! ,upp] ,c>bonif]\s /rata 7 deposit$4 ,! ,c>bonif]\s ,m>9e ,p]iod is ! simple/ ( ! ?ree ) :i* we h to deal1 z ! local oscillations occurr+ on a fairly l>ge scale = su* movem5ts 7 less frequ5t ?an 0 ! case dur+ ! fir/ & ?ird m>9e p]iods4 ,! ?ird m>9e p]iod _h a long %all[-wat] phase at ! comm5cem5t1 ) _m m9or oscillations1 caus+ great v>iation 9 ! "* ( ! deposits & frequ5t m9or uncon=mities4 ,?is %all[-wat] phase exi/$ ?r\gh\t ,jurassic & ,l[] ,cretace\s times4 ,! deep-wat] phase exi/$ dur+ ! deposition ( ! ,upp] ,cretace\s deposits1 & 0 succe$$ by ! second %all[-wat] phase1 :5 ! e>ly ,t]ti>y /rata 7 accumulat$4 ,! diff]5ce betwe5 ! elevations :i* accompani$ ! ,cont95tal ,p]iods & ^? :i* h be5 allud$ to z m9or elevations is no d\bt "o ( degree1 b 9 consid]+ ! ,briti% /rata only no confusion is likely to arise on ?is acc\nt1 z ! diff]5ce 0 "h v great4 ,! ev5ts :i* occurr$ dur+ ! cont95tal p]iods are ( extreme importance to ! geologi/4 ,e great upheaval 0 accompani$ by crumpl+ & /iff5+ ( portions ( ! e>?'s cru/1 & a def9ite tr5d 0 giv5 to ! /rata z ! result ( ^! movem5ts4 ,x is to ! e>?-movem5ts ( ! f\r great cont95tal p]iods t ! pres5t /ructure ( ! ,briti% ,isles is l>gely due1 & 9 any attempt to re/ore ! physical hi/ory ( our isl&s consid]able att5tion mu/ be paid to ! *anges :i* 7 produc$ 9 ! /ratifi$ rocks dur+ ^! p]iods ( e>?-movem5t4 ,,*apt] ,,xiv4 ,,! ,,cambrian ,,sy/em4 ,classification4 ,! rocks ( ! ,cambrian sy/em :5 f\nd repos+ on ,precambrian rocks 9 ,brita9 are always sep>at$ f ! latt] by an uncon=mity4 ,! typical developm5t ( ! rocks ( ! sy/em1 z ! "n implies1 is 9 ! hilly region ( ,ca]n>von%ire & ,m]ione?%ire 9 ,nor? ,wales1 & !y are also well repres5t$ 9 ,s\? ,wales1 ! bord] c\nties betwe5 ,engl& & ,wales1 & ! ,nor?-,we/ ,highl&s ( ,scotl&4 ,two di/9ct classifications ( ! ,cambrian rocks ( ,brita9 are 9 use1 ! orig9al "o f\nd$ on v>iations ( li?ological "*1 :il/ ! second dep5ds ^u fauni/ic diff]5ces1 b ! orig9al li?ological classification has be5 to "s ext5t modifi$ to make x locally correspond ) ! classification bas$ ^u palontological gr\nds4 ,! foll[+ table w %ew ! diff]5ces3-- ,li?ological ,classification4 ,palontological ,classification4 ,tremadoc ,slate ,s]ies#fd ,b$s ) ,int]m$iate ,fauna ,l+ula ,flags ,s]ies ,b$s ) ,ol5us ,fauna ,m5evian b$s 7=m]ly includ$ 9 ,l+ula ,flags7 ,b$s ) ,p>adoxides ,fauna ,=m]ly gr\p$ ,solva b$s toge!r z ,h>le* ,ca]fai b$s or ,llanb]is b$s ,b$s ) ,ol5ellus ,fauna ,footnote #fd3 ,9 accordance ) ! cu/om usually obs]v$ 9 ,brita91 ! ,tremadoc slates are plac$ 9 ! ,cambrian sy/em2 mo/ cont95tal geologi/s place !m 9 ! succe$+ ,ordovician sy/em4 ,! matt] is n an important "o1 z ! fauna is an int]m$iate "o betwe5 t ( ! ,l+ula ,flags & t ( ! ,ar5ig s]ies ( ! ,ordovician sy/em1 & ! b$s are true b$s ( passage4 ,z ! li?ological classification is ess5tially ,briti%1 x w be z well to reta9 ! ,tremadoc ,slates 9 ! ,cambrian sy/em4 ,! orig9al li?ological classification 0 ess5tially ! result ( ,pr(4 ,s$gwick's "w 9 ,nor? ,wales1 :ile ! classification accord+ to faunas is ! outcome ( ! rese>*es ( ,dr ,hicks 9 ,s\? ,wales4 ,description ( ! ,/rata4 ,! ,cambrian rocks ( ,nor? ,wales occur 9 two complex anticl9es1 sep>at$ by an int]m$iate syncl9e ( ,ordovician /rata occupy+ ! ,sn[donian hills4 ,! s\!rly or ,h>le* anticl9e =ms a "p ( ,m]ione?%ire to ! ea/ ( ,h>le*1 :il/ ! nor!rn "o is develop$ ar\nd ,bangor & ,llanb]is4 ,! ,s\? ,wel% ,cambrian rocks are *iefly f\nd on ei!r side ( ! ,pembroke%ire axis ( ,precambrian rocks :i* runs ?r\gh ,/ ,david's4 ,z ! correspond+ rocks ( ! two regions 7 deposit$ 9 ba?ymetrical zones ( mu* ! same dep?1 x w be conv5i5t to give a g5]al acc\nt ( ! rocks ( ! two regions at ! same "t1 leav+ ! /ud5t to acquire in=mation ( ! detail$ v>iations 9 ! l>g] text-books & 9 special memoirs#fe4 ,footnote #fe3 ,a g5]al acc\nt ( ! ,cambrian1 ,ordovician & ,silurian rocks w be f\nd 9 ! ,s$gwick ,essay = #ahhc1 ,a ,classification ( ! ,cambrian & ,silurian ,rocks1 ?\gh ! use ( a cumbr\s nom5clature !re9 w t5d to confuse ! read]4 ,= a detail$ acc\nt ( ! ,cambrian rocks ( ,nor? ,wales ! read] is ref]r$ to ! ,geological ,survey ,memoir1 ,! ,geology ( ,nor? ,wales1 by ,sir ,a4 ,ramsay 7#bnd edition71 he may also consult ,belt1 ,t41 ,on ! ,l+ula ,flags or ,fe/9iog ,gr\p ( ! ,dolgelly di/rict1 ,geol4 ,mag41 ,dec ,i4 vol4 ,,iv4 pp4 #dic1 #ecf1 vol4 ,v4 p4 #e4 ,! geology ( ! ,cambrian rocks is describ$ 9 a s]ies ( ,memoirs 9 ! ,qu>t]ly ,j\rnal ( ! ,geological ,society by ,dr ,h4 ,hicks2 ! foll[+ %\ld be consult$3 ,h>kness1 ,r4 & ,hicks1 ,h41 ,on ! ,anci5t ,rocks ( ! ,/ ,david's ,promontory1 ,s\? ,wales1 & _! ,fossil ,cont5ts1 vol4 ,,xxvii4 p4 #chd2 ,hicks1 ,h41 ,on "s ,undescrib$ ,fossils f ! ,m5evian ,gr\p1 vol4 ,,xxviii4 p4 #agc2 & ,on ! ,tremadoc ,rocks 9 ! neighb\rhood ( ,/ ,david's1 ,s\? ,wales1 & _! ,fossil ,cont5ts1 vol4 ,,xxix4 p4 #ci4 ,see also ,hicks1 ,! ,classification ( ! ,eozoic & ,l[] ,palozoic ,rocks ( ! ,briti% ,isles1 ,popul> ,sci5ce ,review1 ,new ,s]ies1 vol4 ,v41 & ,hicks1 ,life-zones 9 ! ,l[] ,palozoic ,rocks1 ,geol4 ,mag4 ,dec ,,iv4 vol4 ,i4 pp4 #cfh1 #cii & #dda4 ,! /rata ( ! ,ca]fai & ,solva gr\ps %[ ! preval5ce ( ! %all[-wat] phase almo/ un9t]rupt$ly ?r\gh ! :ole ( ! "t occupi$ by _! accumulation 9 ! ,wel% areas4 ,!y consi/ *iefly ( basal conglom]ates1 succe$$ by alt]nations ( grits & %ales1 ?\gh ! latt] are (t5 conv]t$ into slates1 ow+ to ! subsequ5t production ( cleavage4 ,! basal conglom]ates ( ! ,ca]fai b$s are frequ5tly m>k$ by ! exi/5ce ( enorm\s pebbles1 compos$ ( fragm5ts ( ! rocks ( ! und]ly+ ,precambrian gr\ps1 & ! possibility ( ! occurr5ce ( glacial action dur+ _! accumulation z advocat$ by ,dr ,hicks mu/ be tak5 into acc\nt4 ,above ^! b$s are v>i\s col\r$ grits1 ) alt]nations ( muddy s$im5ts (t5 col\r$ r$#ff4 ,! ,solva gr\p consi/s ( massive grits1 ( v>i\s col\rs1 also ) alt]nations ( mud1 :i* h preval5t purple & gre5 hues4 ,! great ?ickness ( ! /rata ( ! ,ca]fai & ,solva ,s]ies1 :i* sometimes exce$s #aj1jjj feet1 mu/ also be not$4 ,footnote #ff3 ,9 giv+ ?is description ! r$ 7,glyn7 slates ( ,nor? ,wales are treat$ z belong+ to ! ,ca]fai s]ies1 ?\gh ?is correlation dep5ds on li?ological *>act]s only at pres5t4 ,! ,m5evian b$s consi/ ess5tially ( v f9e1 well lam9at$ black & grey muds1 :i* are ( a texture fav\rable = ! production ( a some:at regul> jo9t+1 caus+ ! rock to break into small rectangul> blocks4 ,!y are ?91 n exce$+ #fjj feet 9 ?ickness1 & indicate ! incom+ ( ! g5]al deep-wat] phase ( ! ,l[] ,palozoic epo*4 ,! ,l+ula ,flags m>k a local return to %all[] wat] conditions1 especially 9 ! c5tral portion4 ,! total ?ickness is ov] #c1jjj feet1 ( :i* ! l[] /age 7locally ! ,ma5twrog s]ies7 is ov] #ejj feet1 & consi/s ( blacki% muds1 ! middle 7,fe/9iog /age#fg7 is ab\t #b1jjj feet ?ick1 & is compos$ *iefly ( %all[] wat] gritty flags1 :il/ ! upp] 7,dolgelly7 /age is ( ab\t ! same ?ickness z ! l[] /age & has simil> li?ological *>act]s4 ,footnote #fg3 ,! t]m ,fe/9iog has be5 us$ = ! :ole ,l+ula ,flag s]ies z well z = ! middle /age4 ,x w be well to use x ) ref]5ce to ! /age only4 ,! ,tremadoc ,slates are ab\t #a1jjj feet ?ick4 ,!y are divid$ into a l[] & upp] /age1 ( ab\t equal ?ickness1 & are ess5tially compos$ ( iron-/a9$ slates1 ) a consid]able admixture ( calc>e\s matt] 9 "s p>ts ( ,s\? ,wales1 :5 !y furni% ! ne>e/ approa* to a lime/one :i* has be5 f\nd among/ ! ,wel% ,cambrian /rata4 ,!y 7 probably =m$ 9 a fairly deep sea4 ,mu* pyrocla/ic rock & "s lava fl[s are int]calat$ among/ ! ,wel% ,cambrian s$im5ts4 ,tuffs are =m$ 9 ! l[] b$s ( ,/ ,david's1 & lavas & a%es h be5 f\nd among/ ! ,l+ula ,flags & ,tremadoc ,slates ( ,nor? ,wales1 :ile ! ,l+ula ,flags ( ,s\? ,wales h furni%$ sev]al b&s ( a% to ! nor? ( ,hav]=dwe/4 ,mu* ( ! mat]ial ( ! grits & muds may be d]iv$ f volcanic rocks1 ?\gh h[ f> ?is is s _c be /at$ 9 ! abs5ce ( in=mation obta9$ by detail$ petrological exam9ation ( ! rocks4 ,! v>i\s isolat$ outcrops ( ,cambrian /rata among/ ! c\nties ( ! ,wel% bord]s & adjo9+ ,midl& c\nties indicate a great ?9n+ ( ! ,cambrian rocks 9 ?is direction4 ,! probable equival5ts ( ! ,ca]fai rocks occur at ,nuneaton1 ,comley1 & on ! flanks ( ! ,wrek9 & ,malv]n hills4 ,! ?9 basal conglom]ates are succe$$ by qu>tzites1 & sometimes r$ calc>e\s s&/ones 7,comley s&/one74 ,^! rocks are succe$$ by ?9 ar5ace\s & calc>e\s b$s :i* repres5t ei!r ! ,solva or ,m5evian b$s ( ,wales4 ,! ,l+ula ,flags are repres5t$ by ! ,malv]n ,%ales ( ! ,malv]n area & ! ,/ock+=d ,%ales ( ,nuneaton1 :il/ ! ,tremadoc ,slates h z _! equival5ts ! ,%9eton ,%ales4 ,! exact ?icknesses ( ^! deposits d n seem to h be5 record$1 b ,pr(4 ,lapwor? obs]ves t 9 c5tral ,%rop%ire ! ,comley & ,%9eton gr\ps :i* 444 h a collective ?ickness ( p]haps less ?an #c1jjj feet1 we h app>5tly a cond5s$ epitome ( ! entire ,cambrian sy/em z at pres5t g5]ally def9$4 ,! ,cambrian rocks ( ! ,nor?-we/ ,highl&s consi/ ( a ?9 conglom]ate succe$$ by grits & flags ) %aley b$s1 & above ^! a mass ( lime/one1 :i* may repres5t "s ( ! ,ordovician deposits z well z ^? ( ,cambrian age4 ,p5d+ a complete description ( ! faunas ( ^! rocks1 x is suffici5t to /ate t ! only fauna :i* has hi!rto be5 describ$ 9 detail indicates ! exi/5ce ( ,l[e/ ,cambrian rocks4 ,fur!r rem>ks w be made on ?is head :5 describ+ ! "* ( ! ,cambrian faunas4 ,! ,cambrian rocks ( ! ,nor?-we/ ,highl&s are also v ?9 z comp>$ ) ^? ( ,wales1 s t ! ,highl& & ,wel% bord]l& regions appe> to h exi/$ z a deep] sea area ?an t :i* is indicat$ by ! ,cambrian rocks ( ,wales1 an inf]5ce :i* is to "s ext5t borne out by /udy ( ! ,cambrian rocks ( extra-,briti% areas1 to :i* we may n[ turn4 ,! pr9cipal ,european developm5ts ( ,cambrian rock are f\nd 9 ,sc&9avia1 ,russia1 ,bohemia & ,spa91 & ( ^! ! ,sc&9avian "o is by f> ! mo/ fully develop$1 z !re is a complete sequ5ce 9 ! rocks ( t p59sula4 ,!y occur bo? 9 ,norway & ,sw$51 b ! ,sw$i% exposures are ! mo/ int]e/+ 9 mo/ respects1 especially ^? ( ,we/rogo?ia & ,scania4 ,! rocks are ( no great ?ickness1 & consi/ ess5tially ( black c>bonace\s %ales1 ) incon/ant b&s ( impure black lime/one compos$ almo/ entirely ( ! rema9s ( trilobites or m r>ely ( bra*iopods4 ,^! ,alum ,%ales1 z !y are t]m$1 re/ uncon=mably ^u ,precambrian rocks1 & h ar5ace\s & conglom]atic deposits at ! base4 ,9 ,russia ! rocks are /ill fur!r att5uat$1 & h n yield$ ! relics ( s _m faunas z h be5 f\nd 9 ! ,sc&9avian ,cambrian rocks4 ,! ,bohemian developm5t is incomplete1 ow+ app>5tly to an uncon=mity at ! base ( ! ov]ly+ ,ordovician rocks1 :ile ! ,spani% deposits :i* seem fairly ?ick & compos$ l>gely ( me*anical s$im5ts h n be5 work$ out 9 v great detail4 ,! ,am]ican developm5t ( ,cambrian rocks resembles ! ,european "o 9 _m /rik+ p>ticul>s1 & z 9 ! case ( ,europe1 !re are lat]al v>iations 9 ! li?ological *>act]s ( ! rocks1 ?\gh 9 ! opposite direction1 ! %all[-wat] deposits occurr+ on ! ea/ coa/1 & ! deep-wat] deposits fur!r we/4 ,! g5]al di/ribution ( ! diff]5t types ( ,cambrian /rata 9 ,europe & ,nor? ,am]ica has be5 acc\nt$ = on ! supposition t 9 ,cambrian times a tract ( l& lay ov] mu* ( ! pres5t site ( ! ,nor? ,atlantic ,ocean1 & t ! detritus ( t l& =m$ ! %all[-wat] accumulations ( ,wales & ! ea/ ( ,canada1 :il/ fur!r away f x 7 deposit$ ! op5-sea accumulations ( ,sc&9avia & ,russia on "o side & ( ! m we/]ly regions ( ,nor? ,am]ica on ! o!r1 z indicat$ 9 ,fig4 #af4 ,illu/ration3 ,fig4 #af4 ,p4 ,precambrian ,rocks4 ,a4 ,l&4 ,x1 ,x4 ,sea level4 ,,bb4 ,%ore deposits4 ,,cc4 ,deep-wat] deposits4 ,,dd4 ,abyssal deposits4 ,! ,cambrian ,faunas4 ,! ,cambrian ,p]iod has be5 t]m$ ! age ( trilobites1 = !y are ! dom9ant =ms ( ! "t1 b !y are associat$ ) _m o!r =ms ( inv]tebrata2 inde$ all ! great gr\ps ( ?is division are repres5t$ 9 ! e>lie/ ,cambrian fauna4 ,dr ,c4 ,d4 ,walcott records repres5tatives ( ,spongiae1 ,hydrozoa1 ,e*9od]mata1 ,annelida1 ,bra*iopoda1 ,lamellibran*iata1 ,ga/ropoda1 ,pt]opoda1 ,cru/acea & ,trilobita z occurr+ 9 ! ,ol5ellus b$s ( ,nor? ,am]ica & o!r gr\ps are repres5t$ 9 ! rocks ( ?is age 9 ! ,old ,_w4 ,! ,cambrian trilobites z a :ole are ( m g5]alis$ types ?an ^? ( ! lat] sy/ems :i* furni% _! rema9s1 z indicat$ especially by ! loos5ess ( ! body1 & ! l>ge numb] ( body r+s 9 _m ( ! g5]a1 :ile ! tail or pygidium 0 small & =m$ ( only a few coalesc$ segm5ts1 z po9t$ out by ,b>r&e4 ,9 ! lat] trilobites ! te/ is m compact1 !re are on ! :ole few] body r+s1 z m ( ^! h become fus$ into a tail :i* is !re=e l>g] ?an t ( ! av]age tail ( ! ,cambrian trilobite4 ,tak+ ! faunas 9 ord]1 ! olde/ or ,ol5ellus fauna has furni%$ a great v>iety ( =ms 9 ! ,nor?-we/ ,highl&s ( ,scotl&1 ,%rop%ire1 ,sc&9avia1 ,e/honia1 ,s>d9ia1 ,canada1 & ,newf\ndl&1 :il/ repres5tative species ( ! fauna h be5 record$ also f ,worce/]%ire1 ,w>wick%ire1 ,pembroke%ire1 ,india1 ,*9a1 & ,au/ralia4 ,! dom9ant =m is ! trilobite ( ! g5us or gr\p ,ol5ellus1 :i* conta9s a great v>iety ( species ref]able to ?ree or f\r divisions :i* h be5 rank$ z sep>ate g5]a by "s writ]s4 ,associat$ ) ,ol5ellus are trilobites belong+ to o!r g5]a1 :i* are f\nd 9 high] deposits1 ?\gh !re repres5t$ by diff]5t species4 ,bra*iopods are fairly abundant1 especially ^? provid$ ) a horny %ell2 ( ^!1 ! g5us ,kutorg9a is widely di/ribut$4 ,! zoological relation%ips ( sev]al ( ! fossils ( ?is horizon are z yet d\btful4 ,! ,ar*ocya?9 %[ aff9ities ) c]ta9 corals2 a numb] ( te/s1 includ$ 9 ! g5us ,hyoli!s & its allies are d\btfully ref]r$ to ! ,pt]opods1 & ! position ( ! g5us ,volbor!lla is unc]ta94 ,special att5tion is direct$ to ^! d\btful relation%ips1 z x is possible t a numb] ( 'g5]alis$ =ms' ( organisms occur 9 ^! /rata#fh4 ,footnote #fh3 ,= an acc\nt ( ! ,ol5ellus fauna see ,walcott1 ,c4 ,d41 ,! ,fauna ( ! ,l[] ,cambrian or ,ol5ellus ,zone1 ,t5? ,annual ,report ( ! ,director ( ! ,unit$ ,/ates ,geological ,survey1 ,wa%+ton1 #ahij4 ,x is possible t "s ( ! fossils m5tion$ 9 t report belong to /rata above t conta9+ ,ol5ellus4 ,x %\ld be notic$ "h t faunas h be5 discov]$ :i* are possibly ( e>li] date ?an ! ,ol5ellus fauna1 z !y d n correspond ) x1 or ) ^? ( new] /rata4 ,"o1 ! ,neobolus fauna ( ! ,salt ,range ( ,india1 occurs 9 b$s bel[ ^? ) ,ol5ellus1 ?\gh x is n yet cle> t ,ol5ellus w n be ev5tually discov]$ associat$ ) x1 :il/ ! o!r1 ! ,protol5us fauna ( ,canada1 is ( unkn[n age#fi4 ,footnote #fi3 ,= an acc\nt ( ! ,neobolus b$s see ,noetl+1 ,f41 ,on ! ,cambrian ,=mation ( ! ,ea/]n ,salt ,range1 ,records ,geol4 ,survey1 ,india1 vol4 ,,xxvii4 p4 #ga1 & = ! ,protol5us fauna consult a pap] by ,mat!w1 ,g4 ,f41 ,! ,protol5us ,fauna1 ,trans4 ,new ,york ,acad4 ( ,sci5ce1 #ahie1 vol4 ,,xiv4 p4 #aja4 ,! ,ol5ellus b$s are succe$$ by b$s conta9+ ! ,p>adoxides fauna1 :i* h be5 f\nd 9 ,nor? & ,s\? ,wales1 ,%rop%ire1 ,sc&9avia1 ,bohemia1 ,spa91 & ,nor? & ,s\? ,am]ica4 ,ol5ellus & its allies became ext9ct 7or else s sc>ce t no relics ( !m h be5 discov]$ 9 ! ,p>adoxides b$s7 be=e ! comm5cem5t ( ! deposition ( ! /rata conta9+ ! ,p>adoxides fauna1 & few g5]a pass f ! b$s ) ! "o fauna to t conta9+ ! o!r4 ,! ,p>adoxides fauna exi/$ = a consid]able p]iod1 & ! b$s h be5 divid$ into a s]ies ( zones *>act]is$ by diff]5t species ( ,p>adoxides1 ?us ,dr ,hicks records ! foll[+ zones 9 ,pembroke%ire#gj3-- ,zone ( ,p>adoxides ,davidis ,m5evian4 ,hicksii ,aurora ,solv5sis ,solva4 ,h>knessi ,footnote #gj3 ,! ord] "h z else:]e is asc5d+1 i4e4 ! newe/ deposit is plac$ at ! top4 ,dr ,tullb]g divides ! ,p>adoxides b$s ( ,scania into ?irte5 zones1 ?\gh only a few ( ^! are *>act]is$ by def9ite species ( ,p>adoxides4 ,! ,ol5ellus b$s h n yet be5 divid$ into zones1 ?\gh ?is w probably be ! outcome ( fur!r /udy#ga4 ,footnote #ga3 ,! ,p>adoxides fauna is describ$ 9 ! foll[+ works3 ,brita91 ,hicks1 ,h4 & ,salt] ,j4 ,w41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxiv4 p4 #eaj1 ,,xxv4 p4 #ea1 ,,xxvii4 p4 #agc1 & ,hicks1 ,h4 & ,h>kness1 ,r41 ibid4 vol4 ,,xxvii4 p4 #chd2 ,sc&9avia1 ,angel91 ,n4 ,p41 ,palontologia ,sc&9avica2 ,brgg]1 ,w4 ,c41 ,nyt ,magaz9 = ,naturvid5skab]ne1 vol4 ,,xxiv41 ,l9n>sson1 ,g41 ,sv]iges ,geologiska ,und]skn+1 ,s]4 ,c4 ,no4 #ce2 ,bohemia1 ,b>r&e1 ,j41 ,sy/me ,siluri5 du c5tre de la ,bohme2 ,spa91 ,prado1 ,c4 de1 ,sur l'exi/5ce de la faune ,primordiale dans la *ane ,cantabrique suivie de la description des ,fossiles p> ,,mm4 de ,v]neuil et ,b>r&e1 ,bull4 ,soc4 ,geol4 ,france1 #b ,s]ies1 vol4 ,,xvii4 p4 #eaf2 ,am]ica1 ,walcott1 ,c4 ,d41 ,bull4 ,u4 ,s4 ,geol4 ,survey3 ,! ,cambrian ,faunas ( ,nor? ,am]ica1 & ,mat!w1 ,g4 ,f41 ,trans4 ,roy4 ,soc4 ,canada1 #ahhb & succe$+ ye>s4 ,! /rata ) ,p>adoxides are succe$$ by ^? ) ! ,ol5us fauna1 *>act]is$ by ! g5us ,ol5us & a l>ge numb] ( alli$ g5]a or sub-g5]a z "s pref] to t]m !m4 ,! g5us ,ol5us 7s5su /ricto7 is v abundant 9 ! l[] "p ( ! s]ies1 :il/ ! alli$ =ms are m abundant 9 ! upp] b$s4 ,! g5us ,p>adoxides & its associates disappe>$ be=e ! deposition ( ^! /rata conta9+ ,ol5us & its allies1 & inde$ ! complete *ange 9 ! "* ( ! faunas 9 ,europe is v rem>kable4 ,! ,ol5us fauna has be5 f\nd 9 ,nor? ,wales1 ,pembroke%ire1 ,w>wick%ire1 ,worce/]%ire1 & abroad 9 ,sc&9avia & ,canada4 ,x is int]e/+ to note among ! fossils ( ! ,ol5us b$s ! occurr5ce ( a graptolite :i* is associat$ ) ,ol5us 9 ,sc&9avia2 ?is is ! e>lie/ record$ appe>ance ( a gr\p :i* is de/9$ to play s important a role among/ ! fossils ( ! succe$+ sy/em#gb4 ,! foll[+ zones h be5 detect$ by ,dr ,s4 ,a4 ,tullb]g among/ ! ,ol5us b$s ( ,scania3-- ,zone ( ,ac]oc>e ecorne4 ,dictyograptus flabelli=mis4 ,cyclogna?us micropygus4 ,peltura sc>aboides4 ,euryc>e camuricorne4 ,p>abol9a sp9ulosa4 ,c]atopyge sp4 ,ol5us 7prop]74 ,lep]ditia4 ,agno/us pisi=mis4 ,footnote #gb3 ,= descriptions ( ! ,ol5us fauna consult ! foll[+3--,wales1 ,belt1 ,t41 ,geol4 ,mag4 ,dec4 ,i4 vol4 ,v4 p4 #e1 & ,salt]1 ,j4 ,w41 ,decades ,geol4 ,survey1 ,decade ,,ii4 ,pl4 ,,ix4 & ,decade ,,xi4 ,pl4 ,,viii42 ,sc&9avia1 ,angel91 ,n4 ,p41 ,palontologia ,sc&9avica1 & ,brgg]1 ,w4 ,c41 ,die ,siluris*5 ,etag5 #b und #c im ,kri/ianiagebiet und auf ,ek]2 ,canada1 ,mat!w1 ,g4 ,f41 ,illu/rations ( ! ,fauna ( ! ,/ ,john ,gr\p1 ,no4 ,,vi41 ,trans4 ,roy4 ,soc4 ,canada1 #ahia4 ,! b$s ) ,dictyograptus flabelli=mis =m a wond]fully con/ant horizon at or ne> ! top ( ! ,ol5us b$s4 ,!y are f\nd 9 ,nor? ,wales1 ! ,bord] ,c\nties betwe5 ,wales & ,engl&1 ,france1 ,sc&9avia1 ,russia & ,canada4 ,! passage fauna ( ! b$s :i* are ! equival5ts ( ! ,tremadoc ,slates may be spok5 ( z ! ,c]atopyge fauna1 = ,c]atopyge =ficula1 a rem>kable species ( trilobite1 *>act]ises x 9 ,sc&9avia1 & w probably be f\nd else:]e4 ,c]atopyge b$s h be5 f\nd 9 ,nor? & ,s\? ,wales1 ,%rop%ire1 ,sc&9avia1 ,bav>ia & ,nor? ,am]ica1 & 9 ea* case ! fauna is int]m$iate 9 "* betwe5 t ( ! ,cambrian & t ( ! ,ordovician sy/em1 conta9+ ! loosely-=m$ trilobites ( ! =m] ) ! m compact ones ( ! latt]4 ,! g5us ,bryograptus1 a _m-bran*$ graptolite1 also appe>s to *>act]ise ?is fauna#gc4 ,footnote #gc3 ,= acc\nts ( ! ,tremadoc ,slates ,fauna 9 ,engl& & ,wales see ,ramsay1 ,a4 ,c41 ,geology ( ,nor? ,wales1 ,app5dix2 ,hicks1 ,h41 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxix4 p4 #ci2 ,callaway1 ,c41 ibid4 vol4 ,,xxxiii4 p4 #feb1 :il/ _m ( ! =eign fossils are notic$ 9 ,brgg]'s ,die ,siluris*5 ,etag5 #b und #c & ,b>r&e's ,faune siluri5ne des ,environs de ,h( en ,bavire4 ,! faunas ( ! ,cambrian rocks h n be5 /udi$ 9 suffici5t detail1 ) ref]5ce to ! physical surr\nd+s ( ! organisms1 to ?r[ mu* light ^u ! conditions "u :i* ! /rata 7 deposit$1 ?\gh ! evid5ce obta9$ f an exam9ation ( ! li?ological *>act]s ( ! deposits is g5]ally corroborat$ by /udy ( ! organic cont5ts4 ,,*apt] ,,xv4 ,,! ,,ordovician ,,sy/em4 ,classification4 ,! ,ordovician /rata 7 orig9ally divid$ into s]ies by ,s$gwick z foll[s3-- ,upp] ,bala1 ,middle ,bala1 ,l[] ,bala1 ,ar5ig4 ,! ,ar5ig s]ies 0 at "o "t includ$ by "s writ]s ) ! ,l[] ,bala "u ! "n ,ll&eilo1 b ! ^w ,ll&eilo is n[ us$ 9 ! s5se ( ,s$gwick's ,l[] ,bala4 ,! ,middle ,bala is (t5 spok5 ( z ,c>adoc1 b ! t]ms ,bala & ,c>adoc are sometimes us$ int]*angeably4 ,z mu* confusion atta*es to ! use ( ! "n ,bala )\t explanation1 ! alt]native titles h be5 l>gely adopt$1 & z ! s]ies are well def9$ !re is no objection to _! use1 save t "s expression is want$ equival5t to ,upp] ,bala4 ,! local t]m ,a%gill %ales 0 orig9ally appli$ by ,mr ,w4 ,talbot ,avel9e to b$s ( ?is age 9 ,lakel&1 & ,i h else:]e sugge/$ ! use ( ?is "n = ! :ole s]ies 9 t region2 its use may well be ext5d$ to ! s]ies :i* is develop$ 9 _m p>ts ( ,brita9 & ! cont95t4 ,! t]ms :i* w be us$ "h1 !re=e1 = ! diff]5t s]ies ( ! ,ordovician sy/em are ! foll[+3-- ,a%gill ,s]ies 7 ,upp] ,bala7 ,c>adoc 7 ,middle 7 ,ll&eilo 7 ,l[] 7 ,ar5ig ,adopt+ a palontological classification1 we may speak ( ! ,ar5ig & ,ll&eilo b$s z ^? conta9+ ! ,asaphus fauna1 :il/ ! ,c>adoc & ,a%gill b$s possess ! ,tr9ucleus fauna2 ?is is ! t]m9ology employ$ by ,angel9 = ! equival5t /rata ( ,sw$54 ,x mu/ be not$ t "h ! names appli$ are n ^? ( absolutely *>act]i/ic g5]a1 z 0 ! case ) ^? adopt$ = nam+ ! ,cambrian faunas1 = bo? ,asaphus & ,tr9ucleus range ?r\gh ! b$s ( ! sy/em2 b :]eas ,asaphus is mo/ abundant 9 ! b$s ( ! two l[] s]ies1 ,tr9ucleus occurs mo/ frequ5tly 9 ^? ( ! two upp] s]ies4 ,description ( ! /rata4 ,! ,ordovician rocks are f\nd ov] l>ge tracts 9 ,nor? & ,s\? ,wales1 9 ! c\nties on ! ,wel% bord]1 9 ,lakel& & ! outly+ di/ricts 9 ! ,s\!rn ,upl&s ( ,scotl&1 & 9 deta*$ areas 9 ,irel&4 ,!re are ?ree ma9 types ( deposit3--7i7 ! volcanic type1 9 :i* ! ord9>y s$im5ts are associat$ ) a l>ge am\nt ( contemporane\s volcanic matt]1 7ii7 ! black %ale type1 ) a fauna consi/+ l>gely ( graptolites1 & 7iii7 ! ord9>y s$im5t>y type1 9 :i* we f9d alt]nations ( grits1 %ales1 & m or less impure lime/ones4 ,we also f9d developm5ts :i* are int]m$iate betwe5 any two or ev5 all ?ree ( ^! types4 ,! fir/ type is *>act]i/ically develop$ 9 ,ca]n>von%ire & ,m]ione?%ire1 ! second 9 ! ,dumfries%ire ,upl&s1 & ! ?ird 9 ! ,girvan di/rict ( ,ayr%ire4 ,! v>iation 9 ! ?ickness ( ^! ?ree types ( deposit is %[n 9 ! accompany+ sections ( ! ,ca]n>von1 ,m]ione?1 ,m(fat & ,girvan regions 7see ,fig4 #ag74 ,illu/ration3 ,fig4 #ag4 ,%[+ ! v>iations 9 ! *>act]s ( ! ,ordovician deposits ( ! ?ree pr9cipal types4 ,scale #a 94 #ajjj feet4 ,a ,ar5ig4 ,l ,ll&eilo4 ,c ,c>adoc4 ,! ?ickness ( ! ,ar5ig rocks ( ! ,scot* areas is unkn[n4 ,! ,nor? ,wel% area gives two diff]5t developm5ts ( ! ,ordovician /rata1 "o ( :i* is mu* less volcanic ?an ! o!r4 ,9 ! ,m]ione?-,ca]n>von area1 two great masses ( volcanic rock =m ! ,aran & ,ar5ig hills ( ,m]ione? & ! ,sn[donian gr\p ( ,ca]n>von4 ,! =m] are ( ,ar5ig1 ! latt] ( ,c>adoc age4 ,! ,m]ione?%ire volcanic rocks consi/ ( a great ?ickness ( lavas & a%es ( int]m$iate composition 7&]ites71 associat$ ) s&y & muddy s$im5ts ( no great v]tical dep?4 ,! ,ll&eilo b$s ( ?is area are *iefly ( ! nature ( black %ales1 :ile ! ,c>adoc s]ies is repres5t$ by volcanic lavas & a%es ( acid composition 7felsites7 ) a few ?9 int]b$d$ s$im5ts4 ,a calc>e\s a% =m+ ! summit ( ,sn[don is ( importance z be+ on ! same horizon z a lime/one 7! ,bala lime/one7 f\nd 9 ! o!r ,nor? ,wel% area4 ,! ,a%gill s]ies is n repres5t$ 9 ,sn[donia4 ,9 ! o!r ,nor? ,wel% tract1 ar\nd ,bala ,lake1 ! volcanic matt] is mu* less conspicu\s4 ,! ,ar5ig rocks are n se5 ne>] ?an ! ,ar5ig m\nta9s :i* =m ! we/]n b\nd>y ( ?is second tract4 ,! ,ll&eilo b$s consi/ ( %aley deposits ) a well-m>k$ lime/one1 ! ,ll&eilo lime/one1 9 ! c5tre1 :il/ ! ,c>adoc b$s consi/ *iefly ( muddy s$im5ts ) "s ?9 a%es & a lime/one1 ! ,bala lime/one1 at ! top4 ,! ,a%gill s]ies conta9s a basal lime/one1 ! ,rhiwlas lime/one1 succe$$ by %ales1 & ano!r ?9 lime/one call$ ! ,hirnant lime/one at ! summit4 ,9 ,s\? ,wales ! ,ar5ig b$s#gd are *iefly compos$ ( slates1 & are divisible into an upp] & l[] gr\p4 ,! total ?ickness is ab\t #bjjj feet4 ,! ,ll&eilo b$s conta9 ?ree s]ies3-- ,upp] ,ll&eilo ,slates #ajjj ,ll&eilo ,lime/one #bjj ,l[] ,ll&eilo ,slates #hjj4 ,footnote #gd3 ,a rem>kable fauna1 fairly well repres5t$ 9 ,brita9 & exce$+ly well develop$ on ! cont95t1 exi/s 9 ! ,upp]mo/ ,ar5ig & ,l[] ,ll&eilo b$s1 & x is well sep>at$ f ! dom9ant ,ar5ig fauna bel[ & ,ll&eilo fauna above4 ,to ! b$s :i* conta9 x ,dr ,hicks has giv5 ! "n ,llanvirn s]ies4 ,! ,c>adoc b$s consi/ ( black graptolitic %ales ( no great ?ickness1 succe$$ by an impure lime/one on ! horizon ( ! ,bala lime/one1 :ile ! ,a%gill s]ies l t ( ,nor? ,wales is sep>at$ into upp] & l[] lime/one /ages ) an int]v5+ /age compos$ ( %ales4 ,! deposits ( ! ,wel% bord]l& are well develop$ 9 ,%rop%ire1 :]e !re is practically a repetition ( ! ,ca]n>von-,m]ione? developm5t1 ) v>iations 9 detail4 ,! ,ar5ig & ,c>adoc volcanic rocks are n s ?ick z ^? ( ! ,wel% di/rict1 b are nev]!less ( consid]able importance#ge4 ,footnote #ge3 ,= in=mation conc]n+ ^! b$s see ,lapwor?1 ,c4 & ,watts1 ,w4 ,w41 ,! ,geology ( ,s\? ,%rop%ire1 ,proc4 ,geol4 ,assoc41 vol4 ,,xiii4 p4 #big4 ,9 ! hilly region ( ,cumb]l&1 ,we/morl&1 & ! adjo9+ p>ts ( ,york%ire ! succession diff]s f t ( any ( ! ,wel% regions1 = ! great p]iod ( volcanicity 0 dur+ ! =mation ( ! ,ll&eilo rocks1 & !re 7 m]ely sporadic outbur/s 9 ,ar5ig & ,c>adoc times4 ,! ,ar5ig rocks consi/ ( black %ales ) int]/ratifi$ b$s ( co>s] s$im5t1 & "s ?9 lavas & a%es ( int]m$iate type4 ,! ,ll&eilo s]ies is repres5t$ by a v great ?ickness ( volcanic rocks1 v>y+ 9 composition f basic to acid lavas1 ) associat$ pyrocla/ic rocks4 ,! rocks ( ! ,c>adoc p]iod l>gely consi/ ( impure lime/one ) associat$ argillace\s rocks1 & contemporane\s volcanic rocks ( acid "*4 ,a m>k$ uncon=mity is f\nd locally 9 ! c5tre ( ^!4 ,! ,a%gill s]ies consi/s ( a basal lime/one ) %ales above1 & !re is evid5ce t volcanic activity _h n become ext9ct dur+ ! deposition ( ! rocks ( ?is s]ies4 ,pass+ on to ,scotl&1 ! graptolitic type is admirably %[n 9 ! s\!rn ,upl&s ( ! neighb\rhood ( ,m(fat1 ,dumfries%ire4 ,! base ( ! ,ordovician sy/em has n be5 f\nd1 b ! l[e/ s]ies seems to be repres5t$ by %ales ) a graptolite possibly ( ,ar5ig age4 ,above ?is are volcanic b$s succe$$ by a gr\p ( black %ales kn[n z ! ,m(fat %ales4 ,!y are only ab\t six hundr$ feet 9 ?ickness1 & yet repres5t mu* ( ! ,ordovician & "p ( ! ,silurian /rata z develop$ else:]e4 ,! b$s belong+ to ! ,ordovician sy/em are divid$ into two s]ies1 ! ,gl5kiln %ales bel[ & ! ,h>tfell %ales above4 ,! =m] consi/ ( int5sely black muds ) few fossils save graptolites1 & a deposit ( *]t at ! base :i* is compos$ ( radiol>ia4 ,! graptolites ( ! black %ales are ,upp] ,ll&eilo =ms1 b ! ?9 deposit ( radiol>ian *]t may repres5t ! re/ ( ! ,ll&eilo p]iod & "p ( ! ,ar5ig p]iod also4 ,! ,h>tfell %ales are also usually black graptolite %ales ) light] deposits ne>ly b>r5 ( organic rema9s2 !y repres5t ! ,c>adoc & ,a%gill s]ies & pass con=mably into ! deposits ( ,silurian age#gf4 ,! ord9>y s$im5t>y type ( ,ordovician rocks is f\nd 9 ,ayr%ire1 ?\gh a few ?9 graptolitic seams are int]calat$ ) ! conglom]ates & %elly s&s1 clays & lime/ones ( ! region1 :i* is !re=e peculi>ly valuable z af=d+ a means ( comp>ison ( ! %elly type ) ! graptolitic type ( ,ordovician deposits4 ,! ,ar5ig s]ies consi/s ( black %ales ) graptolites1 & ^! rocks are succe$$ by a volcanic gr\p :i* is probably ( ,ll&eilo age4 ,above ^! volcanic b$s1 z 9 ,dumfries%ire1 we f9d ?ree great divisions1 two ( :i* are ( ,ordovician1 ! ?ird ( ,silurian age4 ,! ,ordovician divisions are respectively t]m$ ! ,b>r s]ies1 :i* is ! equival5t ( ! ,gl5kiln %ales1 & ! ,ardmillan s]ies above1 equival5t to ! ,h>tfell %ales#gg4 ,footnote #gf3 ,! ,m(fat b$s are describ$ 9 a pap] by ,pr(4 ,lapwor? entitl$ ,! ,m(fat ,s]ies 9 ! ,qu>t]ly ,j\rnal ( ! ,geological ,society1 vol4 ,,xxxiv4 p4 #bci4 ,?is pap]1 :i* is a ma/]piece ( detail$ "w1 has furni%$ a clue to _m problems4 ,few /ud5ts w be able to foll[ ! num]\s details1 & = g5]al in=mation conc]n+ ! b$s !y are recomm5d$ to read ano!r pap] by ! same au?or ,on ! ,ballantrae ,rocks ( ,s\? ,scotl&1 ,geol4 ,mag4 ,dec4 ,,iii4 vol4 ,,vi4 p4 #bj4 ,an acc\nt ( ! radiol>ian *]ts by ,dr ,g4 ,j4 ,h9de w be f\nd 9 ! ,annals & ,magaz9e ( ,natural ,hi/ory = ,july1 #ahij1 p4 #dj4 ,footnote #gg3 ,see ,lapwor?1 ,c41 ,! ,girvan ,succession1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxviii4 p4 #ecg1 & also ! pap] on ! ,ballantrae ,rocks ref]r$ to 9 ! prec$+ footnote4 ,! latt] pap] %\ld be c>efully read by all /ud5ts ( ! /ratigraphy ( ! ,l[] ,palozoic ,rocks4 ,x is int]e/+ to f9d t 9 ! nor? ( ,irel& ! rocks g5]ally co9cide 9 *>act]s ) ^? :i* are f\nd along ! same l9e ( /rike 9 ,great ,brita92 ?us1 ! ,girvan type appe>s 9 ,londond]ry1 ,tyrone & ,f]managh1 ! ,m(fat type 9 ,c\nty ,d[n1 & ! ,lake ,di/rict type 9 ! c\nties ( ,dubl9 & ,kild>e4 ,on ! cont95t ! volcanic mat]ial :i* plays s important a "p 9 ! con/itution ( ! ,ordovician accumulations ( ,brita9 is practically abs5t1 & ! /rata are l>gely compos$ ( accumulations ( %ale & lime/one ) occasional co>s] deposits4 ,9 ,sc&9avia1 ! ,ar5ig b$s consi/ ( lime/ones ) a few %ales1 ! ,ll&eilo deposits are l>gely calc>e\s1 ^? ( ,c>adoc age are p>tly calc>e\s & t[>ds ! top usually argillace\s1 :ile ! equival5ts ( ! ,briti% ,a%gill s]ies are calc>e\s at ! base & argillace\s at ! summit4 ,9 ,russia ! calc>e\s matt] prepond]ates ov] ! argillace\s mat]ial4 ,ordovician /rata are also f\nd 9 ,belgium1 ,france1 ,bohemia1 & o!r places1 & are l>gely compos$ ( me*anical s$im5ts ( v>y+ degrees ( f95ess mix$ occasionally ) "s calc>e\s matt]4 ,! v>iation 9 ! *>act]s ( ! ,ordovician /rata ( ,brita9 po9ts to accumulation 9 a fairly deep sea1 usually at "s di/ance f ! l&1 b dott$ ov] ) volcanoes :i* (t5 rose above ! wat]1 caus+ ! addition ( mu* volcanic mat]ial to ! ord9>y s$im5ts1 & ! exi/5ce ( m9or uncon=mities at diff]5t horizons along _! flanks4 ,z ^! uncon=mities are n always associat$ ) volcanic mat]ial x is obvi\s t uplifts mu/ h occurr$ occasionally dur+ ! deposition ( ! rocks2 "o important uplift is indicat$ by ! occurr5ce ( an uncon=mity 9 ! ,ar5ig rocks ( ,wales1 :ile ano!r is se5 among/ ! ,c>adoc rocks ( ! ,wel% bord]s4 ,on ! :ole1 h[ev]1 ! p]iod 0 "o ( sl[ subsid5ce1 ! deposition ( mat]ial g5]ally keep+ pace ) ?is subsid5ce1 & accord+ly !re is a great uni=mity ( *>act]s among/ ! /rata ov] wide areas4 ,! probable cont9uation ?r\gh ! ,ordovician p]iod ( ! tract ( l& ov] ! pres5t site ( ! ,n4 ,atlantic ocean :i* z we h reason to suppose exi/$ dur+ ,cambrian times1 is indicat$ by simil> *anges ( li?ological "* among/ ! /rata :5 trac$ f ,brita9 ea/w>d to ,russia 9 bo? ,cambrian & ,ordovician times1 & ! cont9uance ( ^! conditions ov] ! ,am]ican area is also indicat$ by /udy ( ! v>iations among/ ! ,am]ican ,ordovician deposits4 ,! ,ordovician ,faunas4 ,! ,ordovician p]iod has ju/ly be5 t]m$ ! ,p]iod ( ,graptolites1 :i* are ! dom9ant =ms ( ! "t1 & cont9ue 9 abundance ?r\gh\t ! p]iod4 ,! abundance ( graptolites 9 black %ales associat$ ) few o!r organisms has (t5 be5 not$4 ,x appe>s to be due to a l>ge ext5t to ! sl[ accumulation ( ! graptolitic deposits1 all[+ an abundance ( ^! creatures to be %[]$ ^u ! ocean floor1 aft] dea?1 = ! evid5ce d]iv$ f detail$ exam9ation ( _! /ructure po9ts to _! exi/5ce z float+ organisms4 ,! te/s ( o!r creatures l>gely calc>e\s may well h be5 dissolv$ be=e rea*+ ! sea-floor4 ,9 support ( ! view t ^! black %ales are abysmal deposits may be not$ ! s+ul> p]si/5ce ( _! li?ological *>act]s ov] wide areas1 _! replacem5t by mu* great] ?icknesses ( normal s$im5ts along ! anci5t coa/-l9es1 ! frequ5t occurr5ce toge!r ( bl9d trilobites ) ^? hav+ abnormally l>ge eyes :5 ^! creatures are associat$ ) graptolites 9 ! black %ales1 & la/ly ! int]/ratification ( ! black %ales ) radiol>ian *]ts simil> to ! mod]n abysmal radiol>ian oozes4 ,if ?is be s1 we ought to f9d graptolites 9 m>9e deposits ( all k9ds1 & inde$ !y are f\nd !re1 ?\gh l>gely mask$ by ! mass ( s$im5t & ! ho/s ( o!r includ$ fossils1 s t _! discov]y is r5d]$ mu* m difficult ?an :5 !y occur 9 ! black %ales1--a /ate ( ?+s :i* is famili> 9 ! case ( o!r pelagic organisms z ,globig]91 radiol>ia1 & pt]opods1 ^: te/s ab\nd 9 ! abysmal deposits & are comp>atively r>e 9 ^? ( t]rig5\s orig9#gh4 ,footnote #gh3 ,! importance ( ! graptolites z indices ( ! geological age w be se5 by p]usal ( ,pr(4 ,lapwor?'s pap] ,on ! ,geological ,di/ribution ( ! ,rhabdophora1 ,ann4 & ,mag4 ,nat4 ,hi/41 ,s]4 #e1 vol4 ,,iii4 7#ahig74 ,! *>act]s ( ! ,ordovician trilobites h already be5 notic$4 ,^! organisms are abundant1 & occur 9 s$im5ts ( all k9ds4 ,( o!r gr\ps1 ! significance ( ! radiol>ia has be5 ref]r$ to above4 ,corals occasionally =m reef-l masses ( lime/one z 9 ! lime/ones ( ! ,c>adoc epo*2 ! e*9od]ms are well repres5t$1 cy/ids be+ locally abundant2 ( ! cru/acea1 _m rema9s ( te/s ( phylloc>ida h be5 record$2 ! bra*iopods are v abundant1 & ( ! mollusca1 lamellibran*s1 ga/ropods & cephalopods all occur ) frequ5cy ?\gh none ( ^! gr\ps is v preval5t4 ,c]ta9 =ms h be5 ref]r$ to pt]opods ?\gh ) d\bt1 & o!r %ells seem to be ref]able to ! het]opods4 ,! exi/5ce ( v]tebrates dur+ ,ordovician times is n1 9 ! op9ion ( _m geologi/s1 prov$1 ?\gh rema9s ( fi%es h be5 record$ f ! ,ordovician /rata ( ,nor? ,am]ica2 b x is desirable t m evid5ce ( ?is occurr5ce %\ld be giv5#gi4 ,footnote #gi3 ,walcott1 ,c4 ,d41 ,prelim9>y ,notes on ! ,discov]y ( a ,v]tebrate ,fauna 9 ,silurian 7,ordovician7 ,/rata1 ,bullet9 ,geol4 ,soc4 ,am]ica1 vol4 ,,iii4 p4 #aec4 ,! di/ribution ( ! ,ordovician faunas l t ( ! s$im5ts po9ts to ! preval5ce ( op5 ocean conditions ov] wide areas dur+ ! p]iod1 ) occasional approa*es to l&1 :i* 0 (t5 ( a volcanic nature4 ,ar\nd ?is l& clu/]$ ! ord9>y inv]tebrates1 build+ up coral-reefs & %ell-banks1 :il/ away 9 ! op5 oceans ! graptolites float$1 almo/ alone1 & sank to ! ocean floor aft] dea?4 ,,*apt] ,,xvi4 ,,! ,,silurian ,,sy/em ,,& ,,! ,,*anges ,,:i* ,,occurr$ ,,9 ,,brita9 ,,at ,,! ,,close ,,( ,,silurian ,,times4 ,classification4 ,! ,silurian sy/em 0 orig9ally divid$ by its f\nd]1 ,sir ,r4 ,i4 ,mur*ison1 into ?ree s]ies1 z foll[s3-- ,ludl[ ,s]ies ,w5lock ,ll&ov]y ,! t]m ,may ,hill1 propos$ by ,s$gwick1 is sometimes us$ z synonym\s ) ,ll&ov]y4 ,?is classification omits a some:at important set ( b$s int]calat$ betwe5 ^? ( ! ,ll&ov]y & ,w5lock s]ies kn[n z ! ,t>annon %ales1 & 9 ,brita9 if we 7 to classify afre%1 x w\ld be m conv5i5t to include "s ( ! b$s =m]ly ref]r$ to ! ,ludl[ 9 ! ,w5lock4 ,i %all1 h[ev]1 adopt ! old & well-e/abli%$ classification1 add+ ! t]m ,t>annon to ,ll&ov]y1 & speak+ ( ! ,ll&ov]y-,t>annon s]ies4 ,! nature ( ! two classifications is %[n 9 ! foll[+ table3 ,old ,new ,palontological ,/ages4 ,classification4 ,classification4 ,classification4 #a ,upp] ,ludl[ #b ,ayme/ry ,lime/one ,ludl[ ,d[ntonian #c ,l[] ,ludl[ ,fauna ) #d ,w5lock ,lime/one ,encr9urus #e ,w5lock ,%ale ,w5lock ,salopian #f ,woolhope ,lime/one #g ,t>annon ,%ales ,fauna #h ,upp] ,ll&ov]y ,ll&ov]y ,val5tian ) #i ,l[] ,ll&ov]y ,h>pes ,illu/ration3 ,fig4 #ah4 ,l ,ludl[4 ,w ,w5lock4 ,ll-,t ,ll&ov]y-,t>annon4 ,description ( ! /rata4 ,li?ologically ! ,silurian deposits ( ,brita9 =m a cont9uation ( ^? ( ! ,ordovician p]iod1 ) a local int]ruption due to ! elevation ( portions ( ,wales & ! ,wel% bord]s at ! close ( ,ordovician times4 ,else:]e we f9d a pr$om9ance ( %ales pass+ into grits at ! top ( ! sy/em1 ! *ange indicat+ ! incom+ ( ! %all[-wat] phase be=e ! comm5cem5t ( ! second cont95tal p]iod4 ,p>ticul> /ress is laid ^u ! pr$om9ant %aley "* ( ! b$s1 =1 on acc\nt ( ! ri*ness & v>iety ( ! faunas ( ! calc>e\s rocks1 great] att5tion is naturally paid to !m 9 geological works1 & ! /ud5t may get a false idea ( _! relative importance4 ,an attempt is made bel[ 7,fig4 #ah7 to give a g5]al idea ( ! v>iations 9 li?ological *>act]s ( ! ,silurian rocks 9 diff]5t p>ts ( ,brita94 ,! ,silurian /rata are mo/ly f\nd 9 ! same localities z ^? :i* furni% exposures ( ! rocks ( ,ordovician age4 ,! developm5t 9 ! typical ,silurian region ( ! ,wel% bord]s is *>act]is$ by ! abundance ( calc>e\s matt] :i* is f\nd !re z comp>$ ) t :i* exi/s 9 ! o!r ,briti% localities4 ,! ,ll&ov]y /rata are s&y1 (t5 conglom]atic1 ) a fair am\nt ( calc>e\s matt] 9 places4 ,! ar5ace\s nature is und\bt$ly due to ! proximity ( l& caus$ by local upheaval at ! end ( ,ordovician times1 & ! ,upp] ,ll&ov]y rocks sometimes re/ uncon=mably on ! ,l[] ones1 at o!r times on ,ordovician1 ,cambrian1 or ev5 ,precambrian rocks4 ,! ,t>annon %ales are light gre5 %ales ) int]calat$ grits4 ,! ,w5lock s]ies consi/s ( a gr\p ( %ales sep>at+ a l[]1 v incon/ant1 e>?y lime/one f an upp]1 m con/ant1 ?ick] & pur] lime/one4 ,! latt]1 ! ,w5lock lime/one1 is compos$ ( fragm5ts & p]fect specim5s ( v>i\s fossils1 & ! fragm5t>y nature ( _m ( ! %ells indicates ! occurr5ce ( wave-action & probable =mation 9 %all[ wat]1 9 "s places aga9/ coral-reefs4 ,! ,l[] ,ludl[ b$s consi/ ( s&y %ales2 !y are sep>at$ f ! ,upp] ,ludl[ b$s by an impure lime/one1 ! ,ayme/ry lime/one4 ,! ,upp] ,ludl[ b$s consi/ ma9ly ( grits & flags1 (t5 col\r$ r$ t[>ds ! summit4 ,9 ,nor? ,wales ! ,ll&ov]y b$s occasionally pres5t ! %elly ar5ace\s types ( deposit z ne> ,llangoll51 at o!r times z ne> ,conway1 ,corw51 & 9 ,anglesey1 ! graptolitic %ale type4 ,!y also re/ uncon=mably ^u ! ,ordovician rocks 9 ?is area4 ,! ,t>annon %ales resemble ^? ( ! bord] c\nty4 ,! ,w5lock s]ies consi/s ess5tially ( %ales1 :ile ! ,ludl[ developm5t diff]s f t ( ! bord]s 9 its great] ?ickness & ! abs5ce ( any calc>e\s b& 9 ! c5tre4 ,9 ,c5tral ,wales ! graptolitic type ( ! ,ll&ov]y-,t>annon s]ies is f\nd1 b ! graptolite-be>+ %ales ( ! ,ll&ov]y epo* are ?9 b$s occurr+ betwe5 grits & flags no d\bt deposit$ 9 %all[ wat]1 & ?is division ( ! s]ies is ( v great ?ickness4 ,9 ,s\? ,wales ! ,silurian rocks are v simil> to ^? ( ! ,wel% bord]s1 save t ! calc>e\s deposits are few] & ?9n]4 ,! ,lake ,di/rict ,silurian /rata g5]ally resemble ^? ( ,nor? ,wales4 ,! ,ll&ov]y-,t>annon rocks are ( ! graptolite-%ale type1 int]calat$ ) f9e grits 9 ! case ( ! b$s ( ,t>annon age4 ,! ,w5lock b$s consi/ ( %ales1 & ! ,ludl[ b$s ( gritty %ales b5ea?1 & massive flags & grits at ! summit4 ,^! ,ludl[ b$s are "h ( great ?ickness 7c]ta9ly n less ?an #gjjj feet7 & 7 obvi\sly accumulat$ = ! mo/ "p 9 %all[ wat]4 ,! ,ll&ov]y-,t>annon rocks ( ,s\!rn ,scotl& %[ ! two types :i* prevail$ 9 ! ,m(fat & ,girvan areas 9 lat] ,ordovician times4 ,! ,ll&ov]y b$s ( ,m(fat are kn[n z ! ,birkhill %ales1 & are v ?94 ,! repres5tatives ( ! ,t>annon %ales1 h[ev]1 ! ,gala b$s1 consi/ ma9ly ( grits1 & atta9 a great ?ickness4 ,9 ! ,girvan area1 ! ,ll&ov]y b$s are ( ! %elly type4 ,"h z at ,m(fat & 9 ! ,lake ,di/rict !re is p]fect con=mity betwe5 ! b$s ( ,ordovician & ^? ( ,silurian age1 & accord+ly x is in/ructive to note ! complet5ess ( ! palontological break1 especially 9 ! ,m(fat di/rict4 ,! high] ,silurian b$s ( ,s\!rn ,scotl& pres5t a g5]al resemblance to ^? ( ,nor? ,wales & ! ,lake ,di/rict#hj4 ,footnote #hj3 ,= descriptions ( ! ,silurian b$s ( ! typical region see ,lapwor? & ,watts1 ,proc4 ,geol4 ,assoc41 vol4 ,,xiii4 p4 #big1 ^? ( ,wales are describ$ by ,lake & ,groom1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlix4 p4 #dbf1 & ,lake1 ibid4 vol4 ,,li4 p4 #i4 ,a description ( ^? ( ,lakel& w be f\nd 9 ! ,memoir ( ! ,geological ,survey ,! ,geology ( ! ,c\ntry ar\nd ,k5dal1 etc4 :ile ! ,scot* ,rocks are describ$ 9 ,lapwor?'s pap]s on ,m(fat & ,girvan4 ,on ! ,european cont95t we f9d indications ( conditions simil> to ^? :i* prevail$ dur+ ! ,ordovician p]iod2 ! /rata become mu* ?9n] & m calc>e\s 9 ,sc&9avia1 & /ill ?9n] 9 ! ,baltic prov9ces ( ,russia1 :]e !y consi/ v l>gely ( calc>e\s matt]4 ,9 c5tral ,europe ! great] abundance ( calc>e\s matt]1 comp>$ ) t :i* is f\nd 9 ! ,ordovician /rata ( t region1 po9ts to a *ange 9 physical conditions :i* became /ill m m>k$ aft] ,silurian times4 ,9 ,nor? ,am]ica1 ! succession is v simil> to t ( ,brita91 ! calc>e\s developm5t ( ! ,silurian rocks be+ f\nd ar\nd ,niag>a1 b t[>ds ! close ( ,silurian times ! %all[-wat] phase became m>k$ 9 places by ! deposition ( *emical precipitates :i* indicate ! sep>ation ( a portion ( ! late ,silurian ocean f ! ma9 mass dur+ ! p]iod ( =mation ( ^! abnormal deposits4 ,! conditions ( ,silurian times1 until ! adv5t ( ! %all[-wat] phase1 recall ^? ( ,ordovician times & po9t to a wide expanse ( ocean at "s di/ance f ! l&1 ?\gh ! e>lie/ deposits become ar5ace\s :]e !y 7 deposit$ aga9/ an old l& surface =m$ by ! elevation ( ! ,wel% ,ordovician rocks1 :i* 7 d5ud$ to supply ?is mat]ial4 ,"o m>k$ diff]5ce exi/$ betwe5 ! physical conditions ( our area dur+ ,ordovician & ,silurian times1 = ! volcanic activity :i* 0 rife dur+ ,ordovician times almo/ ceas$ dur+ ,silurian times1 except 9 ! region n[ occupi$ by ! extreme s\?-we/ ( ,irel&1 & accord+ly volcanic mat]ial does n appreciably contribute to ! =mation ( ! ,silurian deposits4 ,! %all[ness ( ! sea-floor at times is m>k$ by ! occurr5ce ( masses ( reef-build+ corals 9 ! lime/ones1 & ^! probably indicate ! preval5ce ( a fairly w>m climate1 an inf]5ce support$ by ! nature ( ! ,ga/ropod fauna ( ,go?l&1 z notic$ 9 ,*ap4 ,,ix4 ,! %all[-wat] phase comm5ces fairly simultane\sly ov] ! :ole area at ! beg9n+ ( ! deposition ( ! ,l[] ,ludl[ rocks1 & becomes m m>k$ 9 ! ,upp] ,ludl[ rocks1 be+ mo/ noticeable at _! extreme summit1 :5 a *ange occurr$ :i* w be consid]$ at ! conclusion ( ?is *apt]4 ,! ,silurian ,faunas#ha4 ,! ,silurian p]iod has be5 t]m$ ! p]iod ( ,cr9oids1 & ?is gr\p ( creatures c]ta9ly conta9$ a great v>iety ( v rem>kable =ms1 :i* are specially num]\s 9 ! ,w5lock ,lime/one ( ! ,wel% bord]s1 ,go?l&1 & ,nor? ,am]ica1 b _m ( ! rocks ( ! sy/em display few traces ( ^! organisms4 ,! trilobites & graptolites /ill contribute l>gely to ! fauna1 ! latt] becom+ v sc>ce at ! summit ( ! sy/em1 ?\gh a few specim5s h be5 detect$ 9 ! rocks ( ! succe$+ sy/em4 ,! trilobites belong to few g5]a ?\gh ^! are mo/ly m highly organis$ ?an ^? ( ! ,ordovician p]iod4 ,! g5us ,h>pes has be5 tak5 z fairly *>act]i/ic ( ! l[] "p ( ! sy/em 9 ,sw$51 & x occurs !re abundantly 9 places 9 ,brita91 :il/ ,encr9urus is m abundant 9 ! upp] s]ies1 b bo? ( ^! g5]a range f high] ,ordovician b$s into ! ,devonian4 ,m5tion has already be5 made ( ! corals4 ,bra*iopods are v abundant1 & ,mollusca appe> ) consid]able frequ5cy4 ,! appe>ance ( true insects is ( importance1 cockroa*es h be5 record$ f ,silurian rocks & a numb] ( o!r insects h lately be5 record$ f ,canada#hb4 ,eurypt]ids occur 9 consid]able abundance 9 ! high] p>ts ( ! sy/em1 z d also ! rema9s ( fi%4 ,footnote #ha3 ,= an acc\nt ( ! ,silurian faunas ! /ud5t may consult ,sir ,r4 ,i4 ,mur*ison's ,silurian ,sy/em or ! %ort] ,siluria & ,lapwor?'s pap] on ! ,geological ,di/ribution ( ! ,rhabdophora4 ,footnote #hb3 ,see an article by ,dr ,g4 ,f4 ,mat!w1 ,description ( an ext9ct ,palozoic ,insect & a review ( ! ,fauna ) :i* x occurs1 ,bullet9 ,,xv4 ( ! ,natural ,hi/ory ,society ( ,new ,brunswick4 ,! ,silurian ,rocks ( ! ,little ,riv] ,gr\p ( ,/ ,john1 ,new ,brunswick1 h yield$ species ( l& snails1 two d\btful saw-bugs1 sev]al ara*nids1 & myriopods1 two insects ( ! ord] ,?ysanura 7,spr+-tails71 & eight ,palodictyopt]a4 ,! close ( ,silurian times u%]$ 9 ! second cont95tal p]iod 9 ,brita9 :5 a l>ge "p ( our area & ! adjo9+ areas to ! nor? & nor?-ea/ 7 uplift$ to =m l&1 :i* 9 ! case ( our area 0 int]p5etrat$ by wat]y tracts1 ^: exact nature is /ill a subject ( dispute4 ,accord+ly ! deposits :i* 7 =m$ dur+ ?is p]iod are local & 9 "s cases abnormal1 b !y w be consid]$ 9 ! next *apt]4 ,simultane\sly ) ! =mation ( ^! deposits1 uplift ( ! sea-floor conv]t$ wid] & wid] areas into l&1 & ?is l& und]w5t consid]able d5udation1 s t ! tops ( ! anticl9es 7 worn away4 ,! g5]al tr5d ( ! anticl9es 0 ea/-nor?-ea/ & we/-s\?-we/1 & accord+ly a s]ies ( m\nta9 *a9s possess$ t direction1 = ! epeirog5ic movem5ts 7 accompani$ by orog5ic ones4 ,betwe5 ! regions ( uplifts 7 depressions 9 :i* s$im5ts accumulat$4 ,! pr9cipal axes ( uplift 9 our area range ?r\gh ! ,nor? ( ,scotl& t[>ds ,sc&9avia1 across ! ,s\!rn ,scot* ,upl&s to ! ,nor? ( ,irel&1 ?r\gh ! ,lake ,di/rict & ?r\gh ,wales4 ,z ! result ( lat]al pressure1 a cleavage /ructure 0 impress$ on _m ( ! ,l[] ,palozoic rocks1 ! /rike ( ! rocks ext5d$ 9 ! direction ( ! ridges & depressions1 & ! rocks z a :ole became consid]ably compact$ & h>d5$1 ?us produc+ "o ( ! mo/ important portions ( ! framework ( our isl&1 = al?\gh ! anci5t m\nta9 *a9s 7 l>gely d5ud$ dur+ _! elevation1 & _! /umps 7 aft]w>ds cov]$ by lat] deposits1 ^u ! removal ( ^!1 ! anci5t /umps 7 once m expos$ z fairly rigid masses :i* d n yield greatly to d5ud+ influ5ces1 & accord+ly /& out z ! mo/ important upl& regions ( ,brita9 at ! pres5t day4 ,x is int]e/+ to notice1 z an illu/ration ( ! n[ well e/abli%$ fact t successive e>? movem5ts (t5 occur 9 ! same direction1 t ! axes ( ! folds produc$ dur+ ?is second cont95tal 7,devonian7 p]iod1 run p>allel ) ! l9es sep>at+ tracts ( diff]5t li?ological *>act]s4 ,x has be5 se5 t ! ,ordovician & ,silurian rocks ( ! ,s\!rn ,upl&s cont9ue into ,irel&1 & t ! b$s ( simil> *>act]s run 9 belts hav+ a g5]al ea/-nor?-ea/ & we/-s\?-we/ tr5d1 :i* accord+ly mu/ h be5 ! direction ( ! coa/-l9e p>allel to :i* !y 7 deposit$1 & z t coa/-l9e 0 due to uplift1 ! movem5t :i* produc$ x w\ld naturally produce fold+s ) ea/-nor?-ea/ & we/-s\?-we/ tr5d4 ,?is is "o ( _m cases :]e ! l9es sep>at+ belts ( rock hav+ diff]5t li?ological *>act]s run p>allel to axial l9es ( folds :i* h be5 produc$ 9 ! rocks at a lat] p]iod4 ,z ! result ( ! exi/5ce ( l& ov] p>ts ( nor?-we/ ,europe 9 ,devonian times1 x is comp>atively r>e to f9d a passage f normal ,silurian rocks into normal ,devonian ones2 !re is (t5 an uncon=mity above ! ,silurian /rata4 ,z we proce$ s\?w>ds t[>ds c5tral ,europe1 :]e ! epeirog5ic & orog5ic movem5ts di$ out1 ?is is n ! case1 & we get complete con=mity betwe5 m>9e s$im5ts ( ! ,silurian & ,devonian p]iods4 ,,*apt] ,,xvii4 ,,! ,,devonian ,,sy/em4 ,classification4 ,z a result ( ! movem5ts :i* 7 briefly describ$ 9 ! la/ *apt]1 two types ( ,devonian deposit are f\nd 9 ! ,briti% ,isles1 & are call$ respectively ! ,devon type & ! ,old ,r$ ,s&/one type4 ,! latt] rocks1 =m]ly divid$ into ?ree divisions1 are n[ sep>at$ into two only1 ! upp] & l[] ,old ,r$ ,s&/one1 & ! exact relation ( ^! to ! diff]5t subdivisions ( ! rocks ( ,devon type rema9s to be settl$4 ,! ,devon type itself has giv5 rise to mu* diff]5ce ( op9ion1 two local classifications h be5 appli$1 "o = ! rocks ( ,nor? ,devon & ano!r = ^? ( ,s\? ,devon4 ,! classification :i* has be5 mo/ g5]ally adopt$ is z foll[s3-- ,n4 ,devon4 ,s4 ,devon#hc4 ,pilton ,b$s ,entomis ,slates ,upp] ,devonian ,cuculla 7,m>wood7 ,goniatite ,lime/ones 7,clym5ian7 ,b$s & ,slates ,pickwell ,d[n ,s&/one ,massive ,lime/ones ,middle ,devonian ,morte ,slates ,middle ,devonian 7,eifelian7 ,ilfracombe ,b$s ,lime/ones ,a%pr+ton ,volcanic ,s]ies ,eifelian ,slates & ,%aly ,lime/ones ,l[] ,devonian ,l[] ,devonian ,hangman ,grits ,slates 7,cobl5zian7 ,lynton ,slates ,l9combe & ,w>b]ry ,=el& ,grits ,grits & ,meadfoot ,s&s ,footnote #hc3 ,an acc\nt ( ! ,s\? ,devon rocks by ,mr ,us%] w be f\nd 9 ! ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlvi4 p4 #dhg2 f x ! above classification ( ! rocks ( ,s4 ,devon is tak54 ,! division into ,l[] ,middle & ,upp] ,devonian is g5]ally adopt$1 ?\gh ! alt]native titles giv5 to ^! divisions are n always us$ ) ! same signification1 & ! di/ribution ( ! diff]5t local /ages giv5 9 ! above classifications is usually adopt$ 9 ! ma91 ?\gh a detail$ comp>ison ( ! ,devonian b$s ( ,nor? & ,s\? ,devon is /ill att5d$ ) difficulty4 ,m ?an once an attempt has be5 made to prove t ! app>5t succession ( ! ,nor? ,devon rocks1 :i* is t giv5 9 ! above table1 is n ! true "o1 & ( rec5t ye>s ,dr ,hicks has obta9$ a numb] ( fossils f ! ,morte ,slates :i* _h hi!rto yield$ none1 & he believes t ^! fossils indicate t ! ,morte ,slates are on a l[] horizon ?an ! b$s on :i* !y re/4 ,:atev] be ! ultimate v]dict1 we c1 at any rate1 say t ! ,devonian ,"q1 z x is t]m$1 is n settl$#hd4 ,footnote #hd3 ,see ,hicks1 ,h41 ,on ! ,morte ,slates & ,associat$ ,b$s 9 ,nor? ,devon & ,we/ ,som]set1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vols4 ,,lii4 p4 #bed1 ,,liii4 p4 #dch4 ,description ( ! ,/rata4 ,! g5]al v>iations 9 ! li?ological *>act]s ( ! deposits ( ,devonian age w be se5 f ! accompany+ figure :i* repres5ts ! deposits ( ,brita9 z !y occurr$ f nor? to s\? be=e !y _h be5 affect$ by subsequ5t e>?-movem5ts 7,fig4 #ai74 ,! conv5tional signs :i* are us$ are simil> to ^? :i* h be5 us$ 9 o!r p>ts ( ?is "w1 & w save description ( ! section4 ,illu/ration3 ,fig4 #ai4 ,a4 ,l[] ,palozoic & ,precambrian ,rocks4 ,n4,s4 ,nor? ( ,scotl& ,c4,v4 ,c5tral valley ( ditto ,old ,r$ ,s&/one ,type4 ,w4 ,wales ,n4,d4 ,nor? ,devon ,devon ,type4 ,s4,d4 ,s\? ,devon ,! ridges sep>ate diff]5t deposits ( ,devonian rocks1 :i* 7 possibly deposit$ 9 isolat$ areas1 ?\gh !re 0 probably connexion betwe5 !m at any rate at times4 ,! ,old ,r$ ,s&/one type consi/s to a l>ge ext5t1 z ! "n implies1 ( s&/ones :i* are col\r$ r$ by a deposit ( p]oxide ( iron ar\nd ! s& gra9s4 ,!y are sep>able into a l[] & upp] division ) an uncon=mity (t5 occurr+ betwe5 !m4 ,! l[] ,old ,r$ passes d[n 9 places into ! ,silurian rocks ) p]fect con=mity1 & ! upp] ,old ,r$ simil>ly passes up into ! ,c>bonif]\s /rata4 ,! exi/5ce ( pebble b$s at diff]5t horizons is a notewor?y feature4 ,!y are frequ5tly f\nd at or ne> ! base ( ! two divisions4 ,! s&/ones ( ! l[] division are (t5 accompani$ by flag/ones1 :ile ! r$ s&/ones ( ! upp] division usually h deposits ( yell[ & br[n s&/one int]calat$ betwe5 !m4 ,incon/ant b$s ( lime/one1 kn[n z corn/ones1 are f\nd 9 bo? divisions1 & ,pr(4 ,sollas has %[n t "s ( ^!1 at any rate1 are true me*anical deposits1 =m$ by ! de/ruction ( pre-exi/+ /rata ( lime/one & ! deposition ( ! result+ fragm5ts f a /ate ( susp5sion4 ,9 ,scotl& a great ?ickness ( volcanic mat]ial ( v>i\s k9ds is associat$ ) ! two divisions4 ,= ! sake ( simplicity ?is is omitt$ f ,fig4 #aihe4 ,x is n kn[n h[ f> normal s$im5ts are associat$ ) ! ,old ,r$ ,s&/one type ( deposit4 ,! exi/5ce ( "s 9 ,s\? ,wales is sugge/$ by evid5ce suppli$ by ! late ,mr ,j4 ,w4 ,salt]4 ,footnote #he3 ,= an acc\nt ( ^! & all o!r ,briti% volcanic rocks ! read] is ref]r$ to ,sir ,a4 ,geikie's "w on ,! ,anci5t ,volcanoes ( ,great ,brita94 ,macmillan & ,co41 #ahig4 ,! ,devon type1 z w be se5 9 ! figure1 consi/s ( rocks :i* are to a great ext5t ( normal "*4 ,we f9d 9 ,devon%ire alt]nations ( s&/ones1 %ales & lime/ones1 b ev5 "h1 r$ s&/ones1 :i* are comp>able ) ^? ( ! ,old ,r$ type occur 9 dim9i%$ am\nt3 ! ,=el& ,grits & ,pickwell ,d[n ,s&/ones are bo? col\r$ r$1 & are l ! s&/ones =m$ fur!r nor?4 ,! recognition ( ?is fact induces "o to believe t ! contra/ betwe5 ! two types ( rock :i* are f\nd at a %ort di/ance f "o ano!r on opposite sides ( ! ,bri/ol ,*annel is n s m>k$ z "o is sometimes l$ to suppose4 ,! rocks ( ,nor? ,devon diff] f ^? ( ,s\? ,devon *iefly ow+ to ! am\nt ( calc>e\s s$im5t f\nd 9 ! two areas1 = lime/ones occur 9 ,s\? ,devon to a great ext5t1 & 9 ,nor? ,devon !re is a comp>ative pov]ty ( ?is k9d ( s$im5t4 ,"h1 aga91 ! app>5t diff]5ce is possibly great] ?an ! real "o4 ,! ,nor? ,devon lime/ones h 9 places be5 /ret*$ out aft] _! =mation & ?us r5d]$ ?9n]1 & ! highly-cleav$ lime/ones are occasionally mi/ak5 = %ales1 :ile 9 ,s\? ,devon !re is evid5ce ( ?ick5+ ( ! lime/ones by fold+ subsequ5tly to _! deposition4 ,all[+ = ^! *anges1 h[ev]1 !re is /ill a m>k$ dim9ution 9 ! am\nt ( co>se me*anical s$im5ts & increase 9 ! quantity ( calc>e\s matt] z "o passes f ,nor? to ,s\? ,devon1 & ?is prep>es "o = ! condition ( ?+s met ) on p>ts ( ! cont95t1 :]e ! me*anical s$im5ts become f9] & ?9n] on ! :ole z "o travels s\?w>d1 until1 :5 we rea* ! ,bohemian area1 ! ,devonian rocks are f\nd to be l>gely compos$ ( calc>e\s s$im5ts4 ,x is int]e/+ to f9d t 9 ,nor? ,am]ica ! two types ( ,devonian /rata recur1 & pres5t *>act]s g5]ally simil> to ^? :i* !y possess ^u ?is side ( ! ,atlantic4 ,pass+ n[ to a consid]ation ( ! conditions "u :i* ! ,devonian rocks 7 deposit$1 we may exam9e ! be>+ ( ! "* ( ! /rata z a :ole1 & !n proce$ to m detail$ consid]ation ( ! nature & conditions ( deposits ( ! two types4 ,! gradual increase 9 calc>e\s matt] & dy+ out ( me*anical s$im5ts z "o travels s\?w>d po9ts to recession f l& 9 t direction1 & we h already se5 t ! epeirog5ic & orog5ic movem5ts ( ?is cont95tal p]iod elevat$ ! ,silurian sea-floor 9 ! nor?1 & gave rise to a ,nor!rn ,cont95t1 :ile oceanic conditions cont9u$ fur!r ,s\?1 & all[$ ! accumulation ( s$im5ts ly+ con=mably ^u ^? ( ,silurian age1 & giv+ indications ( ! preval5ce ( physical conditions dur+ ,devonian times :i* 7 9 ! ma9 simil> to ^? ( ! prec$+ ,silurian p]iod4 ,9 ! %all[ wat]s adjo9+ ! l& ( ! ,nor!rn ,cont95t ! ,old ,r$ ,s&/ones 7 laid d[n1 & ! exact conditions "u :i* !y 7 accumulat$ is a matt] ( "s int]e/4 ,! late ,sir ,&rew ,ramsay gave reasons = suppos+ t _m r$ deposits 7 accumulat$ 9 ! wat]s ( inl& lakes1 :i* und]w5t rapid evaporation1 & 8 views h be5 appli$1 ) mu* corroborative evid5ce by ,sir ,a4 ,geikie1 to acc\nt = ! r$ s&/ones ( ,devonian age1 :i* he believes to h be5 accumulat$ 9 a s]ies ( inl& lakes1 ?\gh o!rs hold a diff]5t op9ion1 & consid] t ! ,old ,r$ ,s&/one wat]s _h a direct connexion ) ^? ( ! op5 ocean2 ! "q is too intricate to be discuss$ at l5g? "h4 ,besides ! diff]5ce ( physical *>act]s ( ! two types ( /rata1 ! diff]5ce 9 ! nature ( _! includ$ organisms is significant4 ,! ord9>y inv]tebrates1 z corals1 cr9oids1 bra*iopods & molluscs are extremely r>e 9 ! ,old ,r$ ,s&/one1 :i* conta9s rem>kable rema9s ( ,agna?a fi%es & eurypt]ids1 & al?\gh ^! are also f\nd associat$ ) a true m>9e fauna 9 ,russia1 ,g]many & ,bohemia1 ! r>ity or app>5t abs5ce ( ! ord9>y m>9e inv]tebrates1 ?\gh only negative evid5ce1 :i* is prov]bially dang]\s1 mu/ be reg>d$4 ,! ,nor? ,devon rocks are s$im5ts :i* might well be accumulat$ on ! %ores ( a cont95t1 :ile ^? ( ,s\? ,devon1 ) _! abundant coral reefs1 & o!r organic lime/ones 7 no d\bt deposit$ 9 a cle>] sea1 at a great] di/ance f ! l&1 & ! cle> wat] deposits ( ,g]many & /ill m ( ,bohemia1 7 accumulat$ 9 ! op5 ocean4 ,x is int]e/+ to note 9 ^! ,bohemian deposits abundance ( %ells ( a ,pt]opod ,/yliola :i* has be5 prov$ by ,pr(4 ,h4 ,a4 ,ni*olson to =m masses ( lime/one 9 ! ,devonian sy/em ( ,canada4 ,! mod]n di/ribution ( ! ,pt]opoda sugge/s ! op5 ocean "* ( ! deposits :i* conta9 !m ev5 s f> back z ,devonian times1 ?\gh "o _c conclude t ^! deposits are really analog\s to ! s-call$ ,pt]opod ooze ( mod]n seas :i*1 z a matt] ( fact1 is l>gely compos$ ( =am9if]al te/s ) a consid]able p]c5tage ( pt]opod %ells4 ,! ,devonian flora & faunas4 ,! plant rema9s 9 ! ,l[] ,palozoic rocks are few 9 numb]4 ,"s und\bt$ t]re/rial plants h be5 discov]$1 b ! preval5t flora ( l[] ,palozoic times1 s f> z yet kn[n1 0 "o consi/+ ( ,alg4 ,9 ,devonian times we beg9 to meet ) a numb] ( ,cryptogams ( high] type1 alli$ to ^? :i* =m ! dom9ant flora ( ! succe$+ p]iod4 ,! fauna is 9 _m ways rem>kable4 ,! ,devonian p]iod has be5 t]m$ ! p]iod ( ganoid fi%es1 & ! rem>kable rema9s1 s graphically describ$ by ! late ,hugh ,mill]1 are inde$ peculi>ly *>act]i/ic ( ,devonian times1 b !y are l>gely ?\gh by no means exclusively entomb$ 9 rocks ( ! ,old ,r$ ,s&/one type#hf4 ,! ,devon type ( rock conta9s a great abundance & v>iety ( ! problematical gr\p1 ! ,/romatoporoids1 :i* contribute ext5sively to ! =mation ( _m ( ! lime/ones1 & al?\gh ^! organisms are n by any means conf9$ to ,devonian /rata1 _! abundance & v>iety !re9 might lead "o to speak ( ! p]iod z t ( ,/romatoporoids4 ,! rema9s ( corals are v abundant 9 ! lime/ones1 &1 z already /at$1 frequ5tly give rise to true reef-masses4 ,! graptolites1 z rem>k$ 9 ! previ\s *apt]1 disappe> 9 ! rocks ( ! ,devonian p]iod1 & z only "o or two fragm5ts h be5 f\nd1 we may ass]t t ! gr\p 0 practically ext9ct at ! end ( ,silurian times1 ?\gh species ( "o g5us1 ,monograptus1 l+]$ = a %ort "t 9 greatly dim9i%$ quantity4 ,! trilobites :i* play$ s important a "p among/ ! faunas ( ,l[] ,palozoic times /ill occur fairly abundantly among/ ! rocks ( ! ,devonian sy/em1 & !re is a v int]e/+ po9t to be notic$ 9 connexion ) !m4 ,!y seem to h become practically ext9ct 9 ! succe$+ ,c>bonif]\s p]iod1 :]e few g5]a are f\nd1 & ! decad5ce ( ! gr\p began 9 ,devonian times4 ,9 ^! circum/ances x is int]e/+ to note ! t5d5cy display$ by ! creatures to possess sp9y cov]+s4 ,x is true t ,acidaspis1 ! mo/ sp9ose ( all trilobites1 is abundant 9 ,ordovician & ,silurian /rata1 & t o!r sp9ose trilobites are f\nd !re1 b ! peculi>ity ( ! ,devonian trilobites is1 t g5]a :i* 7 previ\sly smoo?1 or r>ely possess+ "o or few sp9es1 are f\nd repres5t$ by extremely sp9ose species 9 ^! b$s1--! sp9es be+ develop$ f all p>ts ( ! te/1 sometimes z a fr+e to head or tail1 sometimes z prom95t projections f glabella & neck segm5t1 & frequ5tly 9 r[s d[n ! body segm5ts4 ,besides ,acidaspis1 we f9d sp9ose species ( ,phacops1 ,homalonotus1 ,cyphaspis1 ,bronteus & ,encr9urus 9 ,devonian /rata1 & ! occurr5ce ( ^! =ms is s frequ5t & _w-wide1 t "o might p]haps inf] ) confid5ce t an unkn[n fauna conta9+ _m sp9y trilobites 0 ( ,devonian age4 ,footnote #hf3 ,= an acc\nt ( ^! see ,a4 ,s4 ,woodw>d's ,v]tebrate ,palontology4 ,! abundance ( ,eurypt]ids has be5 previ\sly not$4 ,occurr+ z !y d 9 ,silurian rocks1 !y are f> m abundant 9 ^? ( ,devonian age1 & are f\nd indiff]5tly 9 s$im5ts ( ,old ,r$ & ,devon types4 ,( air brea!rs1 sev]al insects h be5 f\nd 9 ! /rata ( diff]5t p>ts ( ! _w4 ,! ord9>y m>9e faunas are o!rwise int]m$iate 9 "* betwe5 ^? ( ! ,silurian & ,c>bonif]\s p]iods1 b !re are sev]al *>act]i/ic ,devonian g5]a1 & no "o :o is acqua9t$ ) ! peculi>ity ( ! ,devonian fauna w\ld d5y to ! ,devonian /rata ! "r to rank z a sep>ate sy/em1 conta9+ a fauna z well m>k$ 9 its way z t ( ! ,silurian sy/em bel[ or t ( ! ,c>bonif]\s above4 ,special /ress is laid ^u ?is po9t because x has be5 sugge/$ t ! ,devonian sy/em %\ld be aboli%$1 & its /rata ei!r divid$ betwe5 ! ,silurian & ,c>bonif]\s sy/ems or ref]r$ exclusively to ! latt] sy/em#hg4 ,footnote #hg3 ,! lit]ature ( ! fauna ( ! ,devonian rocks is a ri* "o4 ,= an acc\nt ( ! ,devonian rocks ( ,brita91 ! read] may consult ! ,monograph ( ! ,devonian ,fossils ( ! ,s\? ( ,engl& by ,rev4 ,g4 ,f4 ,:idb\rne1 :i* is n[ appe>+ 9 ! s]ies ( ,monographs ( ! ,palontographical ,society1 & 9 ! publications ( ! same ,society he w f9d a ,monograph ( ! ,eurypt]ids f ! p5 ( ,dr ,h5ry ,woodw>d4 ,! ri*e/ ,devonian fauna is und\bt$ly t ( ! ,bohemian area1 = ! "w ( ,dr ,e4 ,kays] has conclusively prov$ t ! /ages ,f1 ,g & ,h ( t bas91 =m]ly ref]r$ to ! ,silurian1 are ( ,devonian age1 & an excell5t idea ( ! ri*ness ( ! ,devonian fauna may be obta9$ by /udy+ ! descriptions ( ! fossils f ^? /ages :i* h appe>$ & are appe>+ 9 ,b>r&e's classic "w4 ,,*apt] ,,xviii4 ,,! ,,c>bonif]\s ,,sy/em4 ,! ,classification4 ,! ,briti% rocks ( ! ,c>bonif]\s sy/em h be5 classifi$ accord+ to _! li?ological *>act]s1 b z ! classification has be5 alt]$ f "t to "t1 we may use t :i* seems mo/ acceptable to ! majority ( ,briti% geologi/s at ! pres5t day4 ,accord+ to ?is1 ! b$s are gr\p$ z bel[3-- ,ardwick ,/age ,upp] ,c>bonif]\s ,coal ,measures ,p5nant ,/age ,ganni/] ,/age ,mill/one ,grit ,l[] ,c>bonif]\s ,c>bonif]\s 7,m\nta97 ,lime/one ,s]ies4 ,! ,l[] ,c>bonif]\s b$s h be5 fur!r subdivid$ into3-- ,yor$ale ,s]ies or ,upp] ,lime/one ,%ales1 ,m\nta9 ,lime/one1 ,l[] ,lime/one ,%ales1 ) ,s&/ones & ,conglom]ates1 b z ^! li?ological types are f\nd to be v v>iable :5 trac$ lat]ally = comp>atively %ort di/ances1 x is f\nd m satisfactory to use ! t]ms 9 a purely li?ological s5se r ?an ) *ronological significance4 ,! some:at abnormal developm5t ( ! high] portions ( ! ,c>bonif]\s rocks ( ,brita9 r5d]s ! local classification only p>tially applicable 9 o!r regions1 & z our k progresses1 a palontological classification w probably be adopt$4 ,?is has already be5 done ) ! m purely op5-wat] s$im5ts ( ,russia & ,ea/]n ,asia1 :]e ! developm5t ( ! b$s is m normal4 ,!re ! rocks are classifi$ z "u3-- ,upp] ,c>bonif]\s or ,g%ellian1 ,middle ,c>bonif]\s or ,moscovian1 ,l[] ,c>bonif]\s1 & z ?is classification has already be5 f\nd to be applicable ov] r wide areas1 x is almo/ c]ta9 t1 z 9 ! case ( ! rocks ( o!r sy/ems1 x w prove m s]viceable ?an "o :i* is ma9ly 7?\gh n q exclusively7 bas$ ^u v]tical v>iation ( li?ological *>act]s1 especially z ! ,c>bonif]\s rocks ov] l>ge tracts 9 ,nor? ,am]ica possess faunas :i* are simil> to ^? :i* h be5 discov]$ 9 ,russia1 ,ea/]n ,asia & ,nor? ,africa4 ,description ( ! /rata4 ,! v>iations 9 ! li?ological *>act]s & fossil cont5ts ( ! ,briti% ,c>bonif]\s /rata :5 trac$ f nor? to s\? h be5 s frequ5tly describ$1 & utilis$ z a means ( illu/rat+ ! indications z to local v>iations 9 physical conditions :i* are suppli$ by ^? /rata1 t little ne$ be said ^u ! subject4 ,! re/oration ( ! physical geography ( ,c>bonif]\s times ov] ! ,briti% area w be f\nd 9 a *apt] by ! late ,pr(essor ,gre5 9 ! "w ^u ,coal by v>i\s pr(essors at ! ,york%ire ,college ( ,sci5ce & also 9 ,pr(4 ,hull's ,physical ,hi/ory ( ! ,briti% ,isles4 ,"s modifications mu/ be made 9 ^! re/orations z ! result ( rec5t rese>*1 ! pr9cipal be+ caus$ by discov]ies among/ ! ,c>bonif]\s rocks ( ,devon%ire4 ,tak+ ! /rata 9 v]tical succession1 we f9d evid5ce ( ! occurr5ce ( a complete m>9e p]iod 7! second great m>9e p]iod7 betwe5 ! second & ?ird cont95tal p]iods4 ,! fir/ %all[-wat] phase ov] a great portion ( ! ,briti% ,isles is m>k$ by ?9 t]rig5\s s$im5ts1 indicat+ t ! p]iod 0 a brief "o2 x 0 foll[$ by ! deep-wat] phase1 probably ( "s l5g?1 la/+ ?r\gh ! great] "p ( ! rema9d] ( ,l[] ,c>bonif]\s times2 :ile ! conclud+ %all[-wat] phase 0 l5g?y z comp>$ ) t ( ! beg9n+ ( ! p]iod1 & is m>k$ by ! accumulation ( ! great ?ickness ( deposits belong+ to ! ,mill/one ,grit & ,coal ,measures4 ,!re is no d\bt1 h[ev]1 t 9 "s p>ts ( ! ,briti% area m9or *anges produc$ local t]re/rial conditions dur+ ! p]iod1 & accord+ly we f9d t ! deepe/ wat] deposits ( ! sy/em 9 ,brita9 are succe$$ by an uncon=mable junction ) ! s$im5ts ( ! upp] portion ( ! sy/em4 ,! g5]al *ange 9 ! li?ological *>act]s ( ! b$s ( ! ,l[] ,c>bonif]\s division :5 trac$ f s\? to nor? is %ewn 9 ! foll[+ diagram 7,fig4 #bj74 ,x w be se5 t ! l& & op5 sea areas 7 9 ! respective positions :i* !y occupi$ dur+ ,devonian times1 b t z ! result ( great] subm]g5ce1 ) :i* ! accumulation ( s$im5t did n keep pace1 ! %all[-wat] m>9e deposits ( ,devonian age are 9 ,devon replac$ by op5-sea deposits#hh1 :ile %all[-wat] m>9e deposits fur!r nor? replace ! anomal\s deposits :i* 7 f\nd !re dur+ ! ,devonian p]iod4 ,footnote #hh3 ,! ,radiol>ian ,*]ts ( ! ,l[] ,c>bonif]\s rocks ( ,devon1 & ! associat$ s$im5ts1 toge!r ) ! uncon=mity betwe5 ^! & ! ,upp] ,c>bonif]\s b$s are describ$ by ,messrs ,h9de & ,fox1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,li4 p4 #fji4 ,illu/ration3 ,fig4 #bj4 a4 ,radiol>ian *]ts ( ,devon4 b4 ,m\nta9 lime/one ( ,c5tral ,engl&4 c4 ,me*anical s$im5ts ( ,nor!rn ,engl&4 d4 ,fre%wat] deposits ( ,s\!rn ,scotl&4 ,o4,r4 ,old] rocks4 ,ow+ to ! accumulation ( ?ick masses ( s$im5t1 ! ,l[] ,c>bonif]\s sea ( ! nor? ( ,engl& appe>s to h be5 l>gely silt$ up1 & al?\gh ! organic deposits ( ! s\? are s ?9 t !y did n r5d] ! sea %all[ 9 t region1 ! g5]al level ( ! ,l[] ,c>bonif]\s floor ( ! s\? 0 also uplift$1 & actually conv]t$ into l&1 z ! result ( ! upw>d movem5t :i* took place 9 ,devon%ire & tracts ( ,france2 & ow+ to silt+ up 9 ! nor?1 & elevation 9 ! s\?1 a g5]al plane surface 0 produc$ ov] v ext5sive areas1 n only 9 ,brita9 b ^u ! ,cont95t1 ^u :i* ! peculi> deposits & accumulations ( ,upp] ,c>bonif]\s times 7 laid d[n1 sometimes 9 %all[ wat]1 sometimes ^u ! l&1 & (t5 "u conditions :i* _c at pres5t be det]m9$ ) accuracy4 ,t ! deposits ( ! ,mill/one ,grit & ,coal ,measure epo*s 7 to a l>ge ext5t laid d[n 9 wat] is admitt$ by all1 & 9 ! case ( _m ( ! deposits ( ! ,mill/one ,grit1 & "s ?9 deposits ( ! ,coal ,measures1 x is equally cle> t ! wat] area 0 "p ( an expanse ( ocean1 = we f9d m>9e fossils1 z corals1 cr9oids1 & cephalopods1 9 ^! b$s4 ,associat$ ) !m 9 ! ,coal ,measures are o!r b$s 9 :i* ! ord9>y ,c>bonif]\s g5]a ( m>9e inv]tebrates are abs5t1 & _! place is tak5 by %ells :i* be> mu* resemblance to ! mod]n fre%-wat] mussel1 & x has be5 ma9ta9$ ) good reason t z ! ord9>y m>9e =ms are r>ely or nev] mix$ ) ^? resembl+ rec5t fre%-wat] %ells1 ! latt] are truly fre%-wat]#hi4 ,if ?is be s1 _m ( ! me*anically =m$ s$im5ts ( ! ,coal ,measures 7 ( fre%-wat] orig91 laid d[n 9 %all[ lagoon-l expanses1 probably %ut (f f ! ma9 ocean by a n>r[ portion ( int]v5+ l&1 :i* 0 occasionally de/roy$1 ?us p]mitt+ incursions ( salt-wat] :5 "s ( ! ord9>y m>9e inv]tebrates ( ! p]iod obta9$ a tempor>y foot+ 9 ! area4 ,footnote #hi3 ,= fur!r in=mation ^u ?is subject ! /ud5t %\ld consult ! ,introduction to a ,monograph on ,c>bonicola1 ,an?racomya & ,naiadites 7! %ells 9 "q7 by ,dr ,:eelton ,h9d1 be+ "o ( ! ,monographs ( ! ,palontographical ,society4 ,!re is n only a diff]5ce ( op9ion z to ! mode ( accumulation ( _m ( ! me*anical s$im5ts ( ! ,coal ,measures1 b also z to t ( ! coal-seams :i* accompani$ !m4 ,two diff]5t !ories h be5 put =w>d to acc\nt = ^! coal-seams1 :i* are usually spok5 ( z ! drift !ory & ! gr[?-9-place !ory4 ,accord+ to ! =m]1 9 its extreme application1 coal is an aque\s deposit =m$ by ! settlem5t ( drift$ masses ( vegetation ^u ! floor ( a wat]-tract1 :ile ^? :o pu% ! gr[?-9-place !ory to its extreme limits ma9ta9 t coal is ! result ( gr[? ( vegetation ^u ! actual site :]e ! coal is n[ f\nd4 ,mu* app>5tly conflict+ evid5ce has be5 advanc$ by ! advocates ( ! two hypo!ses1 & special cases ( coal-=mation h be5 appeal$ to by ea* 9 support ( _! views2 ?us ! exi/5ce ( coal compos$ l>gely ( bodies :i* resemble ! spores ( mod]n lycopods1--objects ( s res9\s a nature t !y float on ! surface until !y are decompos$1--is cit$ by ! uphold]s ( ! gr[?-9-place !ory1 :ile ! support]s ( ! o!r hypo!sis c po9t ) equal =ce to ! occurr5ce ( ! f9ely divid$ c>bonace\s mud conta9+ rema9s ( fi%es :i* gives rise to cannel coal 9 "s places4 ,"o ( ! ma9 ass]tions 9 support ( ! gr[?-9-place !ory 0 t ( ! suppos$ univ]sality ( 'und]clays' or old surface soils b5ea? all coal-seams1 b ?\gh ^! are common1 !y are f> f univ]sal4 ,x is impossible to d ju/ice 9 small compass to ?is "q ( coal-=mation1 b x may be po9t$ out t mu* ( ! diff]5ce ( op9ion c be und]/ood if x be rememb]$ t ! t]m 'coal' is r a popul> t]m :i* has be5 admitt$ into sci5tific t]m9ology1 & !re=e us$ some:at loosely1 ?an a /rictly sci5tific t]m appli$ to a def9ite sub/ance1 & accord+ly1 j z at ! pres5t day we f9d c>bonace\s sub/ances gr[+ 9 "o place on l& to =m peat1 9 o!r places on a tract sometimes dry & sometimes subm]g$1 to =m ! c>bonace\s deposits ( ! cypress-swamps1 & once m accumulat$ b5ea? ! %all[s ( a sea z a s$im5t to =m ! c>bonace\s muds ( ! ocean m>g9s :]e ! mangroves gr[1 s ! div]se sub/ances :i* are includ$ "u ! g5]al t]m coal may h accumulat$ 9 "o place on l&1 9 ano!r b5ea? wat]1 & 9 a ?ird on an area alt]nately dry & subm]g$4 ,?is is n a "q ( great importance2 ! important po9t is t accumulations ( vegetation on a fairly l>ge scale are f\nd at ! pres5t day on pla9s1 = ev5 if !y gr[ on m\nta9 regions1 ! deposits are readily d5ud$ be=e !y are cov]$ up1 & also x mu/ be not$ t a moi/ climate is necess>y = ! gr[? ( mu* vegetation4 ,! conclusion t ! accumulations ( coaly matt] 7 =m$ on pla9s is borne out by _! great horizontal ext5t z comp>$ ) _! ?ickness1 & x is n[ g5]ally agre$ t ! coal vegetation :i* is f\nd 9 ! normal coal-measures 0 ess5tially a swamp vegetation4 ,an attempt has be5 made to prove t an upl& vegetation ( v diff]5t "* exi/$ contemporane\sly ) x1 b reasons w be giv5 9 ! sequel = conclud+ t ?is suppos$ upl& ,c>bonif]\s flora is ev]y:]e ( lat] date4 ,! lat] %all[-wat] phase ( ,c>bonif]\s times1 z already /at$1 0 unusually long1 x 0 also v widespread1 & appe>s to h be5 accompani$ ov] wide areas by humid conditions dur+ its cont9uance1 & accord+ly ! m>% conditions :i* exi/$ dur+ ,upp] ,c>bonif]\s times 7 probably on a l>g] scale ?an t ( simil> conditions be=e or aft]4 ,special /ress is laid ^u ?is fact1 z x is a good illu/ration ( ! view :i* seems to be ga9+ gr\nd1 t e p]iod possess$ peculi> conditions nev] to be repeat$1 :i* mu/ h left _! impress ^u ! "* ( ! s$im5ts4 ,?\gh ! conditions above describ$ 7 widespread1 !y 7 naturally n univ]sal1 & accord+ly 9 _m p>ts ( ! _w1 z previ\sly /at$1 we f9d true m>9e deposits ( ,upp] ,c>bonif]\s times1 ?\gh ev5 ^! 7 sometimes replac$ dur+ "p ( ! epo*1 by conditions :i* 7 fav\rable = ! =mation ( coal-seams 9 ^? places4 ,int]ruption 9 ! cont9uance ( a humid temp]ate climate ov] ! regions ( ,nor?-,we/ ,europe is also sugge/$ by ! discov]y ( deposits :i* are ma9ta9$ to be ( glacial orig9 among/ ! ,coal ,measures ( ,france#ij4 ,footnote #ij3 ,= an acc\nt ( ! num]\s volcanic products see ,sir ,a4 ,geikie's "w on ,! ,anci5t ,volcanoes ( ,great ,brita94 ,! ,floras & ,faunas4 ,! flora ( ! ,c>bonif]\s rock is s notewor?y t ! p]iod has be5 t]m$ ! ,p]iod ( ,cryptogams2 ! rema9s ( f]ns1 horsetails1 & clubmosses pr$om9ate1 & _m ( ! =ms rea*$ a gigantic size4 ,?\gh ! floras ( ! v>i\s /ages are m>k$ by a g5]al resemblance1 !re are diff]5ces :i* enable ! palobotani/ to asc]ta9 ! /ratigraphical position ( ! b$s by ref]5ce to ! includ$ plant rema9s1 & a consid]able numb] ( successive floras h be5 describ$#ia4 ,! inv]tebrate fauna does n diff] on ! :ole v greatly f t ( ,devonian times1 ?\gh ! trilobites are n[ becom+ r>e1 & ! mollusca assume a m prom95t position z comp>$ ) ! bra*iopods4 ,corals occur 9 abundance 9 ! calc>e\s deposits ( ! p]iod1 & frequ5tly give rise to %eets ( reef-=mation1 b ! =am9if]a & cr9oidea c]ta9ly play ! pr9cipal "p z lime/one-produc]s1 & ! influ5ce ( ! latt] 9 giv+ rise to great masses ( lime/one :i* are frequ5tly us$ = ornam5tal purposes is too well kn[n to ne$ m ?an pass+ ref]5ce4 ,! air-brea!rs h also be5 detect$ 9 great] abundance1 ?\gh !y are r>e1 :5 we consid] ! comp>atively fav\rable conditions = _! pres]vation pres5t$ by ! ,coal ,measure rocks4 ,myriopods1 ara*nids1 insects & pulmonif]\s ga/ropods h h[ev] be5 f\nd ) tol]able frequ5cy4 ,! dang] ( argu+ f imp]fect data is well illu/rat$ by ! great addition to our k ( ! insect-fauna ( ^! times due to ! exploration ( ! b$s ( "o small coal-field1 t ( ,comm5try 9 ,france1 ( :i* ! insects h be5 describ$ by ,m4 ,c4 ,brongni>t4 ,! v]tebrates are repres5t$ by a consid]able v>iety ( fi%es1 & less abundant ?\gh tol]ably num]\s rema9s ( ,amphibia1 :i* occur 9 ! ,c>bonif]\s rocks ( ! ,nor? ( ,engl&1 ,irel&1 ,france1 ,nor? ,am]ica & else:]e4 ,footnote #ia3 ,consult ,kid/on1 ,r41 ,on ! ,v>i\s ,divisions ( ! ,c>bonif]\s ,rocks z det]m9$ by _! ,fossil ,flora1 ,proc4 ,roy4 ,phys4 ,soc4 ,ed941 vol4 ,,xii4 p4 #ahc4 ,! exi/5ce ( def9ite zones ( organisms 9 ! case ( ! ,c>bonif]\s rocks has be5 d5i$1 & x appe>s to be consid]$ by "s t ! ,c>bonif]\s rocks 7 accumulat$ s rapidly z comp>$ ) rocks ( "s o!r sy/ems t ! fauna rema9$ v simil> ?r\gh\t4 ,x is v d\btful if ?is 0 s4 ,9 ! case ( o!r sy/ems1 ! division into zones has only be5 accompli%$ by means ( m detail$ rese>*es ?an ^? :i* h be5 conduct$ among/ ! ,c>bonif]\s rocks ( ,brita93 aga91 ! occurr5ce ( successive floras sugge/s t !re may h be5 a simil> succession among/ ! faunas1 & f9ally we f9d t zonal division has be5 c>ri$ on to "s ext5t among/ ! ,c>bonif]\s /rata ( o!r regions4 ,! foll[+ classification ( ! ,russian type ( s$im5t may prove useful1 z an indication ( ! possibility ( m detail$ sep>ation ( our own b$s3-- ,b$s ) ,spirif]a fascig]a1 ,spirif]9a ,g%ellian ,s>anae1 c4 7) ,fusul9a & ,b$s ) ,producta cora1 ,p4 uralica1 ,ar*im$ipora7 ,cam>ophoria crum5a1 c4 ,b$s ) ,syr+opora p>allela & ,spirif]a /riata4 ,moscovian ,/age ( ,spirif]a mosqu5sis4 ,/age ( ,spirif]a ,kle9i4 ,coals1 ,s&/ones & ,%ales ) ,noegg]a?ia ,l[] ,c>bonif]\s t5ui/riata & ,producta gigantea4 ,/age ( ,producta mesoloba4 ,! m>9e fauna ( ! ,upp] ,c>bonif]\s b$s1 :i* is s poorly repres5t$ 9 ,brita91 b is well develop$ 9 ,spa91 ,russia1 ,asia & ,nor? ,am]ica1 is l>gely *>act]is$ by ! abundance ( =am9if]s ( ! g5us ,fusul9a & ,fusul9ella & ( bryozoa ( ! g5us ,ar*im$ipora4 ,x is v desirable t ! truly m>9e fauna ( ! ,spirorbis lime/one & o!r m>9e b&s ( ! ,briti% ,coal ,measures %\ld be c>efully /udi$ to see if !y pres5t any close relation%ip ) t ( ! ,g%ellian b$s#ib4 ,footnote #ib3 ,a good idea ( ! g5]al *>act]s ( ! ,c>bonif]\s fauna ( ,brita9 w be obta9$ f an exam9ation ( ,pr(essor ,phillips' ,geology ( ,york%ire1 ,"p ,i41 & ,mr 7n[ ,sir ,f47 ,mc,coy's ,c>bonif]\s ,fossils ( ,irel&1 :ile ! nature ( ! ,european fauna is well illu/rat$ 9 ,pr(4 de ,kon9ck's well-kn[n "w ,description des animaux fossiles qui se tr\v5t dans le t]ra9 c>bonifre de ,belgique4 ,= an acc\nt ( ! *>act]s ( ! m>9e fauna ( ! ,upp] ,c>bonif]\s rocks ! read] %\ld consult ! "w on ,geology & ,palontology publi%$ by ! ,geological ,survey ( ! ,/ate ( ,ill9ois 9 #ahff4 ,,*apt] ,,xix4 ,,! ,,*anges ,,:i* ,,occurr$ ,,dur+ ,,! ,,?ird ,,cont95tal ,,p]iod ,,9 ,,brita92 ,,& ,,! ,,=eign ,,p]mo-,,c>bonif]\s ,,rocks4 ,at ! close ( ,c>bonif]\s times a m>k$ *ange took place 9 ! nature ( ! e>?-movem5ts4 ,! preval5t depression :i* occurr$ ov] ! ,briti% & adjo9+ regions dur+ ,c>bonif]\s times 0 replac$ by upw>d movem5t1 accompani$ by orog5ic folds1 :i* once m br\ght on cont95tal conditions & develop$ a s]ies ( m\nta9 ranges4 ,! *ange is m>k$ ev5 at ! close ( ,c>bonif]\s times by ! abnormal r$ s&/ones ( ! upp]mo/ "p ( ! ,c>bonif]\s sy/em :i* are f\nd ar\nd ,:itehav5 9 ,cumb]l& & ,ro!rham 9 ,york%ire1 z ! ,:itehav5 ,s&/one & ,ro!rham ,r$ ,rock4 ,^! movem5ts cont9u$ ?r\gh ,p]mian & ,triassic times1 & x is to !m & to ! climatic conditions ( ! p]iods1 t ! anomal\s nature ( ! ,p]mo-,triassic deposits is l>gely due1 z w be %ewn 9 ! succe$+ *apt]s4 ,at pres5t x is our purpose to call att5tion to ! effect ( ^! movem5ts ^u ! s$im5ts :i* _h be5 deposit$ previ\sly to _! occurr5ce4 ,ov] ! ,briti% area1 two diff]5t sy/ems ( orog5ic movem5t c be detect$1 produc+ folds ( :i* ! axes run approximately at "r angles to "o ano!r4 ,"o ( ^!1 ( :i* ! ,p5n9e sy/em is ! be/ repres5tative 9 ,brita91 caus$ ! production ( elevations hav+ axes 9 a g5]al nor? & s\? direction1 & we may !re=e speak ( x z ! ,p5n9e sy/em ( movem5t1 :ile ! o!r1 :i* gave rise to folds runn+ 9 an ea/ & we/ direction1 is well repres5t$ 9 ! ,m5dip ,hills1 & may be !re=e t]m$ ! ,m5dip sy/em1 ?\gh x is m widely kn[n z ! ,h]cynian sy/em1 z1 on ! ,cont95t1 ! rocks :i* are greatly affect$ by x =m ! f\ndations ( ! region occupi$ by ! anci5t ,h]cynian =e/4 ,! effects ( ^! sy/ems 7 9 ! ma9 simil>2 !y result$ 9 ! uplift ( p>allel belts ( c\ntry to =m hill-ranges ) int]v5+ l[l&s1 b :5 /udi$ 9 detail ! movem5ts are se5 to be ( a diff]5t "*4 ,! ,p5n9e sy/em ( movem5ts 0 ( a type :i* is famili> to ! geologi/s z develop$ 9 ! ,great ,bas9 ,region ( ! we/]n t]ritories ( ,nor? ,am]ica1 & produc$ :at is spok5 ( z ,bas9-,range /ructure4 ,! movem5ts 7 ( ! nature ( direct uplift1 caus+ fracture1 only accompani$ by fold+ 9 a m9or degree1 & accord+ly ! hills are compos$ ( t]rac$ sc>ps1 ) "o g5tly slop+ side1 & "o /eep sc>p-side1 ! latt] on ! up?r[ side ( ! fault1 z se5 9 fig4 #ba4 ,9 ! ,m5dip sy/em1 ! folds 7 ( ! ,alp9e type1 :i* is a famili> product ( lat]al pressure1 consi/+ ess5tially ( ov]folds1 ?\gh ^! are (t5 complicat$ by rev]s$ faults4 ,( ! ,p5n9e sy/em1 ! ,p5n9e ,*a9 itself furni%es ! mo/ notewor?y example 9 ,brita91 b we h indications ( o!r folds ( ?is sy/em1 su* z t :i* runs f ! ,lake ,di/rict to ! ,ayr%ire coa/1 :i* is p>tly conceal$ z ! result ( o!r movem5ts1 & a /ill m m>k$ "o1 9 ! rocks ( ! ,malv]n ,hills4 ,illu/ration3 ,fig4 #ba4 a a4 ,"o /ratum displac$ by faults f f4 h4 ,hills4 ,! ,m5dip sy/em is well %ewn 9 ! ,m5dip ,hills1 b ! rema9s ( a /ill m important anticl9e are se5 9 ,s\? ,devon & ,cornwall1 sep>at$ f ! ,m5dip ,hills by ! great syncl9e ( ,devon4 ,ano!r p>allel anticl9e runs f ,lanca%ire to ,york%ire at "r angles to ! ,p5n9e ,*a9 & sep>ates ! coal-field ( ,cumb]l& & t ( ,nor?umb]l& & ,durham1 f ^? ( ,s\? ,lanca%ire1 & ,york%ire1 ,notts1 & ,d]by%ire4 ,on ! ,european cont95t ! ,ural ,*a9 is ! mo/ important uplift ( ! sy/em ( :i* ! ,p5n9e ,*a9 =ms a m9or repres5tative1 :ile ! ,h]cynian sy/em has caus$ ! compression & /iff5+ ( _m ( ! ,c>bonif]\s & e>li] rocks :i* n[ rise to ! surface 9 _m p>ts ( c5tral ,europe4 ,! ext5sive cont95tal area :i* 0 ! result ( ^! uplifts n only det]m9$ ! =mation ( abnormal deposits1 b all[$ ! occurr5ce ( a long p]iod ( "t subsequ5tly to ! close ( ! ,c>bonif]\s p]iod1 ( :i* few deposits n[ expos$ 9 ,europe are repres5tative1 & we mu/ accord+ly seek o!r regions 9 ord] to f9d typical repres5tatives ( ?is ,p]mo-,c>bonif]\s p]iod1 ( :i* ! /rata develop$ 9 ! ,salt ,range ( ,india h be5 mo/ c>efully work$1 especially by ,dr ,waag51 ?\gh m>9e s$im5ts ( ! p]iod are kn[n else:]e1 z 9 ,spitsb]g51 ! ,ural ,m\nta9s1 ,*9a & ,au/ralasia2 & a gr\p ( some:at anomal\s s$im5ts ( ?is age 9 p>ts ( ,india1 ,au/ralia & ,s\? ,am]ica is ( peculi> int]e/1 on acc\nt ( ! insight z to ! climatic conditions ( ! times :i* x af=ds4 ,! ,p]mo-,c>bonif]\s ,rocks4 ,9 ! ,salt ,range ( ! ,nor?-,we/ ( ,india an int]e/+ s]ies ( s&/ones alt]nat+ ) lime/ones re/s uncon=mably ^u l[] rocks4 ,! s&/ones are kn[n z ! ,speckl$ ,s&/ones1 :ile ! lime/ones are t]m$ ! ,productus ,lime/ones4 ,! ,l[] & ,middle ,speckl$ ,s&/ones are succe$$ by ! ,l[] ,productus ,lime/one :i* is sep>at$ f ! ,l[] division ( ! ,middle ,productus ,lime/one by ! ,upp] ,speckl$ ,s&/one2 ^! are all ( ! ,p]mo-,c>bonif]\s p]iod1 :ile ! upp] "p ( ! ,middle ,productus ,lime/one & ! ,upp] ,productus ,lime/one belongs to ! ,p]mian p]iod4 ,! fossils1 l>gely inv]tebrates1 are int]m$iate 9 "* betwe5 ^? ( ,c>bonif]\s & ,p]mian ages4 ,simil> fossils are f\nd 9 ! m>9e ,p]mo-,c>bonif]\s b$s ( ! o!r areas :i* h be5 nam$ above4 ,! ,l[] ,speckl$ ,s&/one is ( int]e/ on acc\nt ( ! occurr5ce ( b\ld]-b$s )9 x1 & ?is division ( ! s&/one has be5 correlat$ ) ! l[e/ 7,tal*ir7 /age ( ! ,p]mo-,c>bonif]\s /rata ( o!r p>ts ( ,india1 :ile ! o!r ,speckl$ ,s&/ones & ^? divisions ( ,productus ,lime/one :i* are ref]r$ to ! ,p]mo-,c>bonif]\s are correlat$ ) ! high] divisions ( o!r p>ts4 ,special m5tion is made ( ! ,tal*ir division1 on acc\nt ( ! occurr5ce !re9 ( b\ld] b$s :i* h long be5 kn[n1 & ^: glacial orig9 0 inf]r$ by ,dr ,w4 ,t4 ,blan=d =ty ye>s ago4 ,! accumulations %ew signs ( hav+ be5 deposit$ 9 wat]1 b ! exi/5ce ( l>ge subangul>1 sometimes /riat$ b\ld]s !re91 :i* mu/ h come f di/ant s\rces1 & ! occasional occurr5ce ( /riat$ rock surfaces on ! /rata ^u :i* ! ,tal*ir b$s repose uncon=mably po9ts to ice-action2 ?is w\ld n be s v rem>kable if x 7 an isolat$ case1 ?\gh suffici5tly s1 f ! comp>ative ne>ness ( ! region to ! equator2 b rese>*es conduct$ 9 diff]5t p>ts ( ! s\!rn hemisph]e h br\ght to light simil>1 & sometimes ev5 m /rik+ evid5ces ( glacial action 9 widely di/9ct regions#ic4 ,9 ,au/ralia !y h be5 f\nd 9 ,new ,s\? ,wales1 ,victoria1 ,s\? ,au/ralia1 ,ea/ ,au/ralia & ,tasmania2 ! ,dwyka b\ld]-conglom]ates ( ,s\? ,africa & c]ta9 deposits ( simil> "* discov]$ by ,pr(4 ,d]by 9 ,s\!rn ,brazil h be5 ref]r$ to ! same p]iod1 & _! glacial orig9 has also be5 inf]r$4 ,?is widespread di/ribution ( deposits :i* are g5]ally contemporane\s1 ( :i* ! glacial orig9 may n[ be tak5 z e/abli%$1 is extremely rem>kable1 & mu/ be tak5 into c>eful consid]ation by ^? :o put =w>d !ories fram$ to acc\nt = =m] climatic *anges4 ,footnote #ic3 ,! read] w f9d an excell5t acc\nt ( ! ,p]mo-,c>bonif]\s glacial deposits 9 a pap] by ,pr(4 ,edgwor? ,david1 entitl$ ,evid5ces ( ,glacial ,action 9 ,au/ralia 9 ,p]mo-,c>bonif]\s ,"t 7,qu>t4 ,j\rn4 ,geol4 ,soc4 ,vol4 ,,lii4 p4 #bhi74 ,9 ?is pap] o!r glacial b$s besides ^? ( ,au/ralia are notic$4 ,! ,flora & ,fauna4 ,! flora ( ! ,p]mo-,c>bonif]\s b$s has caus$ z mu* discussion z ! "q conc]n+ ! orig9 ( ! b\ld]-deposits4 ,9 ! s\!rn hemisph]e1 ! ,p]mo-,c>bonif]\s rocks ( ^? c\ntries :i* h yield$ b\ld]-b$s also conta9 rema9s ( a flora :i* is n[ kn[n z ! ,glossopt]is flora1 f ! prevail+ g5us1 :i* is associat$ ) o!r g5]a1 su* z ,gangamopt]is4 ,^! fossils appe> to be f]ns1 ?\gh _! mod]n allies h n be5 indicat$ ) c]ta9ty2 associat$ ) !m are r>e cycads & conif]s4 ,! ,glossopt]is flora is m>k$ly contra/$ ) ! ,coal-,measure flora ( ! nor!rn hemisph]e ) its giant lycopods4 ,moreov] ,glossopt]is appe>s 9 ! nor!rn hemisph]e 9 rocks ( lat] date ?an ! ,p]mo-,c>bonif]\s p]iod4 ,x has be5 sugge/$ t ! ,glossopt]is flora orig9at$ 9 a cont95t 9 ! s\!rn hemisph]e1 on :i* ! b\ld] b$s 7 also =m$ 9 isolat$ wat] areas1 & t "s ( ! =ms migrat$ nor?w>ds4 ,to ?is cont95t ! "n ,gondwanal& has be5 appli$ by ,pr(4 ,suess1 f ! ,gondwana s]ies ( ! ,p]mo-,c>bonif]\s rocks ( ,india1 9 :i* ! ,glossopt]is flora is f\nd1 & x has also be5 ma9ta9$ t ! s\!rn ,glossopt]is flora 0 contemporane\s ) ! nor!rn flora ( ord9>y ,coal-measure type1 ?\gh :e!r ?is 0 s to any ext5t rema9s to be prov$1 = ! b$s conta9+ ! ,glossopt]is flora are di/9ctly new] ?an any :i* h furni%$ a typical nor!rn ,coal-measure flora4 ,9 any case1 ! *ange ( floras betwe5 ,coal ,measure & ,p]mo-,c>bonif]\s times is v m>k$1 & :5 tak5 9 connexion ) ! widespread glacial deposits1 is "o ( ! mo/ /rik+ ph5om5a display$ by ! rocks ( ! /ratifi$ column#id4 ,footnote #id3 ,= an acc\nt ( ! ,glossopt]is flora & its geological relations1 consult ,sew>d1 ,a4 ,c41 ,sci5ce ,progress1 ,janu>y1 #ahig1 p4 #agh4 ,! fauna has already be5 notic$4 ,x consi/s ( bra*iopods1 "s ( :i* are ( peculi> g5]a4 ,! g5]al simil>ity ( ! faunas 9 regions s remote z ,spitsb]g51 ! ,ural ,m\nta9s1 ,india1 & ,new ,s\? ,wales1 indicates an ext5sive sea dur+ ! p]iod4 ,x c h>dly be suppos$ t ! fauna ( ,p]mo-,c>bonif]\s times has be5 completely describ$1 = ! fossils ( "o or two areas only h be5 made kn[n to u ) any degree ( fulness1 & :5 ! ,p]mo-,c>bonif]\s & m>9e ,p]mian faunas are z well kn[n z ^? ( ,triassic times 7& ! latt] h only be5 fully describ$ v rec5tly7 !re is no d\bt t ! important break :i* 0 at "o "t suppos$ to exi/ betwe5 ,palozoic & ,mesozoic faunas w be fill$ 9 satisfactorily#ie4 ,footnote #ie3 ,! ,p]mo-,c>bonif]\s b$s are describ$ 9 ,messrs ,m$licott & ,blan=d's ,geology ( ,india1 second edition 7edit$ by ,mr ,r4 ,d4 ,oldham71 & figures ( "s ( ! important fossils giv5 !re94 ,= full] in=mation ! read] %\ld ref] to ,waag5's acc\nt ( ! ,salt ,range ,fossils & ,fei/mantel's description ( ! plants 9 ! ,memoirs ( ! ,geological ,survey ( ,india4 ,,*apt] ,,xx4 ,,! ,,p]mian ,,sy/em4 ,classification4 ,x has already be5 obs]v$ t z ! result ( ! ,p5n9e & ,m5dip sy/ems ( e>?-movem5t1 ! ,c>bonif]\s rocks ( ,brita9 are succe$$ by a m>k$ uncon=mity1 & t ! rocks ( ! succe$+ ,p]mian & ,triassic sy/ems ( ,brita9 %ew an abnormal developm5t4 ,! pr9cipal areas :]e ,p]mian rocks are f\nd are on ei!r side ( ! ,p5n9e ,*a9 9 ! ,nor? ( ,engl&1 b sporadic exposures ( rocks ( ?is age are f\nd 9 "s ( ! ,midl& & ,s\!rn c\nties4 ,! ,p]mian rocks h be5 well /udi$ 9 ,g]many1 & ! ,g]man names are sometimes adopt$ 9 ,brita91 & ! foll[+ comp>ison w prove useful3-- ,brita94 ,g]many4 ,magnesian ,lime/one ,magnesian ,lime/one ,ze*/e94 ,m>l ,slate ,kupf]s*ief] ,l[] ,p]mian ,s&/ones ,ro?lieg5de4 ,! t]m ,ze*/e9 has be5 appli$ 9 a some:at diff]5t s5se by diff]5t writ]s1 b ! "o giv5 9 ! table appe>s to f9d mo/ fav\r4 ,9 a region :i* 0 ess5tially cont95tal1 consid]able v>iations 9 ! li?ological *>act]s ( ! rocks may be expect$1 :5 ! /rata are trac$ lat]ally1 b we nev]!less f9d t ! diff]5ces are n s great z 0 =m]ly suppos$ to be ! case :5 c]ta9 r$ s&/ones ly+ above recognis$ ,p]mian /rata 9 ! di/rict on ! we/ side ( ! ,p5n9e ,*a9 t[>ds its nor!rn extremity 7 also ref]r$ to ! ,p]mian2 ^! s&/ones 7! ,/ ,bees ,s&/ones7 are n[ g5]ally admitt$ to be ( ,triassic age1 & comp>ison betwe5 ! rocks on opposite sides ( ! ,p5n9e ,*a9 is mu* simplifi$1 z se5 bel[4 ,we/ side4 ,ea/ side4 ,?9 ,magnesian ,lime/ones & ,m>ls ,magnesian ,lime/one ,hilton ,%ales ,m>l ,slate ,p5ri? ,s&/one & ,brockrams ,l[] ,p]mian ,s&/ones4 ,description ( ! ,/rata4 ,on ! ea/ side ( ! ,p5n9e ,*a91 ! ,l[] ,p]mian s&/one is an incon/ant deposit (t5 consi/+ ( yell[ false-b$d$ ar5ace\s /rata4 ,! ,m>l ,slate is an argillace\s %ale1 (t5 conta9+ bitum9\s matt]1 & yield+ sev]al fi%-rema9s & "s plants2 x is usually only a few feet 9 ?ickness4 ,! ,magnesian ,lime/one is typically develop$ 9 ,durham z a yell[ or greyi% lime/one conta9+ a v>iable p]c5tage ( c>bonate ( magnesia2 :5 trac$ s\?w>d1 x alt]s its *>act]s1 becom+ mix$ ) me*anical deposits1 & "s *emical precipitates 9 places1 s t at ,mansfield x appe>s z a r$ s&/one ) gra9s cem5t$ by a mixture ( c>bonates ( lime & magnesia2 &1 l ! re/ ( ! ,p]mian /rata1 x has disappe>$ :5 we rea* ,nott+ham4 ,9 addition to ! s\?w>d ?9n+ ( ! ,p]mian b$s ( ?is area1 !re is "s evid5ce ( _! disappe>ance 9 a we/]ly direction1 ?\gh1 z ! pres5t /rike ( ! b$s is ne>ly nor? & s\?1 ! indications ( ?is are less conv9c+4 ,on ! ea/ side ( ! ,p5n9e ,*a91 ! ma9 diff]5ce obs]vable is ! relative ?ickness ( ! major divisions4 ,! ,l[] ,p]mian s&/ones h ?ick5$ out consid]ably1 :ile ! reput$ repres5tatives ( ! ,magnesian ,lime/one are ?94 ,! ,p5ri? s&/one is ( consid]able int]e/4 ,x conta9s 9 places1 z ne> ,appleby1 ?ick deposits ( breccia consi/+ ( angul> fragm5ts *iefly compos$ ( ,c>bonif]\s ,lime/one1 :i* 9 _m cases h und]gone subsequ5t dolomitisation1 emb$d$ 9 a matrix ( r$ s&/one4 ,?is breccia is kn[n z brockram4 ,_m b$s ( ! ,p5ri? s&/one are compos$ ( cry/all9e gra9s ( s&1 due to deposition ( silica 9 cry/all9e cont9uity ) ! qu>tz ( ! orig9al gra9 aft] ! =mation ( ! deposit2 ( m significance1 = our pres5t purpose1 is ! pres5ce ( o!r accumulations ( ! s&1 9 :i* ! individual gra9s (t5 approa* ! =m ( sph]es1 ?us resembl+ ! 'millet-se$' s&s ( mod]n des]t regions4 ,! ,hilton %ales are grey s&y %ales1 ) plant rema9s1 & above !m are v>iable deposits includ+ ?9 magnesian lime/ones :i* h yield$ no fossils4 ,! isolat$ ,p]mian deposits ( ! midl& & s\!rn c\nties ( ,engl& consi/ ( r$ m>ls & s&/ones ) occasional breccias1 & 9 ! abs5ce ( fossils1 _! exact position 9 ! ,p]mian s]ies is /ill unkn[n4 ,! ,g]man ,p]mian rocks resemble ^? ( ,brita91 especially z se5 9 ,durham1 9 _m p>ticul>s1 & give indications ( =mation "u physical & climatic conditions g5]ally simil> to ^? :i* 7 !n preval5t 9 ! ,briti% area4 ,at ,/assfurt1 9 ,g]many1 ! less soluble con/itu5ts ( ocean wat] are accompani$ by a great v>iety ( salts3--*lorides1 sulphates & borates2 & ! v soluble salts ( potassium & magnesium kn[n z ! ,abraum salts are f\nd 9 abundance z well z ! less soluble salts ( sodium & calcium4 ,! occurr5ce ( ^! v soluble salts is s infrequ5t on a l>ge scale among ! rocks ( ! ,geological ,column1 & ! matt] is "o ( s great !oretical import1 t x is necess>y to take special note ( _! pres5ce 9 ! ,p]mian /rata4 ,! frequ5t exi/5ce ( *emical deposits 9 ! ,p]mian ,rocks ( ,n4,w4 ,europe1 ! =mation ( r$ s&/ones1 & ! dolomitisation ( lime/one b$s & fragm5ts ( pre-exi/+ lime/ones po9t to inl& seas ( a ,caspian "*1 :ile ! evaporation necess>y = ! =mation ( ! precipitates also indicates a fairly w>m temp]ature4 ,! pres5ce ( millet-se$ s&s1 9 v l5ticul> pat*es1 sugge/+ =m] s&-dunes1 & ! occurr5ce 9 places ( breccias 7l "s p>ts ( ! brockram7 almo/ devoid ( matrix1 pil$ up aga9/ pre-exi/+ cliffs1 recall+ screes ( mod]n times1 give almo/ c]ta9 evid5ce ( ! occurr5ce ( l& tracts mo/ probably ( des]t "*1 dur+ "p ( ! p]iod ( accumulation ( ! mat]ials ( ! ,p]mian rocks4 ,! fossil evid5ce supports ?is view1 & geologi/s are mo/ly agre$ t ! ,p]mian rocks ( nor?-we/ ,europe 7 accumulat$ 9 an area ( des]t "*1 occupi$ 9 "p by inl& seas1 ?\gh !re is mu* diff]5ce ( op9ion z to ! ext5t ( ^! seas1 "s geologi/s hold+ t a numb] ( isolat$ %eets ( wat] 7 necess>y to produce ! di/ribution & "* ( ! accumulations4 ,x is /ill a vex$ "q ) ,briti% geologi/s h[ f> ! ,p5n9e ridge /ood up z l& dur+ ! p]iod1 b leav+ ?is & o!r m9or consid]ations out ( acc\nt1 x may be not$ t ! simil>ity ( deposits 9 ! diff]5t areas1 :e!r we exam9e ! ord] ( succession1 ! li?ological *>act]s or ! includ$ fossils1 sugge/s communication betwe5 ! wat] tracts ( diff]5t regions1 ?\gh ?is communication ne$ n h be5 m ?an a s]ies ( /raits1 or comp>atively n>r[ belts ( wat]#if4 ,footnote #if3 ,x %\ld be m5tion$ t "s writ]s h inf]r$ ! evid5ce ( glacial conditions ov] p>ts ( ! ,briti% area1 on acc\nt ( ! resemblance ( "s ( ! ,p]mian breccias to rec5t glacial deposits4 ,! "q is /ill sub judice4 ,x is n necess>ily oppos$ to ! exi/5ce ( des]t conditions1 if ! m\nta9s 7 suffici5tly high1 = ! ,wahsat* regions adjo9+ ! ,bas9 ,region ( ,n4 ,am]ica h be5 glaciat$4 ,! ext5sive developm5t ( ,p]mian & ,triassic rocks ) t]re/rial *>act]s 9 ! s\!rn hemisph]e also1 & ! abs5ce ( new] deposits 9 _m places1 sugge/s t ! l& areas ( ^! times 9 t hemisph]e h l>gely rema9$ su* ev] s9ce1 9 :i* case1 ! ,p]mo-,triassic s]ies ( movem5ts produc$ a m>k$ direct effect ^u our pres5t cont95tal areas1 & at any rate produc$ an indirect "o ^u ! ,briti% l& tracts4 ,! pres5ce ( anomal\s deposits ( ,p]mian age ov] wide areas ne$ n be surpris+1 b x w\ld be inde$ rem>kable if no ord9>y m>9e type ( ,p]mian rocks 0 kn[n1 & ! rese>*es ( rec5t ye>s h prov$ t ?is type is ext5sively develop$1 9 ,ea/]n ,europe1 ,asia1 & ,nor? ,am]ica1 :]e ,p]mian rocks consi/+ ( lime/ones1 ) a great] or less admixture ( me*anical deposits1 occur 9 "s abundance4 ,! /udies ( ,waag5 & o!rs 9 ,india h giv5 u ! f>!/ insight into ! nature ( ^! b$s4 ,bel[ is a g5]al classification tak5 f ,waag5's "w3-- ,salt ,range4 ,g]many4 ,base ( ,trias ,unfossilif]\s ,%ale & ,s&/one ,passage ,b$s into ,trias ,top ,b$s ( ,upp] ,productus ,lime/one ,cephalopoda ,b$s ( ,upp] ,gypsum ,b$s ,productus ,lime/one ,middle ,division ( ,upp] ,productus ,lime/one ,ze*/e9 79 re/rict$ s5se7 ,l[] ,division ( ,upp] ,productus ,lime/one ,upp] ,division ( ,middle ,weisslieg5de & ,kupf]s*ief] ,productus ,lime/one ,middle ,division ( ,middle ,ro?lieg5de4 ,productus ,lime/one ,x w be se5 t 9 ! ,salt ,range !re is a complete passage f ! ,p]mo-,c>bonif]\s /rata ?r\gh ! ,p]mian into ! ,trias1 & ! detail$ "w :i* has be5 c>ri$ out by ,waag5 & o!rs among/ ! rocks ( ! ,salt ,range mu/ make ?is1 = ! pres5t at all ev5ts1 ! type area = ! m>9e developm5t ( ! /rata ( ,p]mo-,c>bonif]\s & ,p]mian ages4 ,! ,p]mian flora & fauna4 ,! ,p]mian flora pres5ts "s difficulties4 ,! flora ( ! ,ze*/e9 consi/s l>gely ( f]ns & conif]s1 b t ( ! ,ro?lieg5de ( ,g]many has be5 comp>$ ) t ( ! ,c>bonif]\s1 & if a true ,p]mian flora ( ! nor!rn hemisph]e has _m =ms ( ,c>bonif]\s aff9ities1 ! pres5ce ( ! ,glossopt]is flora 9 ,p]mo-,c>bonif]\s rocks ( m s\!rly regions seems to imply its orig9 !re & sl[ migration nor?w>ds4 ,x mu/ be not$1 h[ev]1 t ! ,ro?lieg5de has be5 divid$ by "s geologi/s into an upp] & l[] division1 ( :i* ! l[] is actually ref]r$ to ! ,c>bonif]\s sy/em4 ,all t c be n[ said is1 t our k ( ! floras ( ,p]mo-,c>bonif]\s & ,p]mian times is /ill incomplete1 & t ! difficulties w no d\bt be cle>$ up z ! result ( fur!r "w4 ,! inv]tebrate fauna ( ! nor?-we/ ,european ,p]mian deposits is *iefly noticeable on acc\nt ( ! paucity ( species1 ?\gh individuals are (t5 abundant4 ,! %ells are also sometimes /unt$ & occasionally di/ort$4 ,^! *>act]s be> out ! supposition t ! aque\s deposits 7 laid d[n 9 inl& seas ( ,caspian "* & n 9 ! op5 ocean4 ,polyzoa1 bra*iopods1 & lamellibran*s pr$om9ate1 b o!r gr\ps are f\nd4 ,! v]tebrates consi/ ( =ms ( fi%1 amphibia & reptiles1 & ! ,p]mian rocks are ! e>lie/ /rata 9 :i* ! rema9s ( true ,reptilia are kn[n to occur ) c]ta9ty4 ,! ,reptiles belong to ! ord]s ,anomodontia 7,!romora7 & ,rhyn*ocephalia1 ( :i* ! =m] is exclusively ,p]mian & ,triassic1 :ile ! latt] is abundant 9 ! /rata ( ^? p]iods1 b is repres5t$ at ! pres5t day by ! g5us ,sph5odon ( ,new ,zeal&4 ,! ,amphibia belong to ! ord] ,labyr9?odontia :i* ranges f ,c>bonif]\s to ,l[] ,jurassic1 b ! memb]s ( ! ord] are mo/ abundant 9 ,p]mian & ,triassic /rata1 & ^! p]iods may be spok5 ( z ! ,p]iods ( ,labyr9?odonts4 ,a few words mu/ be said ( ! fauna ( ! truly m>9e ,p]mian b$s4 ,x is mu* ri*] ?an t ( ! abnormal deposits ( nor?-we/]n ,europe1 & its /udy is important z furni%+ ano!r l9k betwe5 ,palozoic & ,mesozoic life4 ,_m ,palozoic g5]a pass up into ! ,p]mian rocks1 &1 z w be ultimately se51 sev]al occur 9 ^? ( ! ,triassic sy/em1 & "o or two ev5 9 ! basal ,jurassic /rata1 ?\gh ,mesozoic =ms pr$om9ate 9 ! ,l[] ,jurassic ,rocks1 & !re is a fairly equal admixture ( =ms usually consid]$ z ,palozoic & ( ^? g5]ally reg>d$ z ,mesozoic 9 ,triassic rocks1 :ile ! ,palozoic =ms /ill pr$om9ate ov] ! ,mesozoic 9 ! ,p]mian /rata4 ,along ) ^! *>act]i/ic ,palozoic g5]a1 x is int]e/+ to f9d repres5tatives ( m ?an "o g5us ( ! tribe ( ,ammonites1 :i* is to take s prom95t a place 9 ! fauna ( ! ,mesozoic rocks1 among/ ! true m>9e ,p]mian s$im5ts ( ,india & o!r areas4 ,! ann\ncem5t ( ! contemporaneity ( ammonites ) fossils reg>d$ z exclusively palozoic 0 receiv$ ) consid]able d\bt1 b ?is contemporaneity is n[ cle>ly e/abli%$1 & ne$ n be reg>d$ z 9 any way anomal\s4 ,) ! deposition ( ! ,p]mian rocks1 ,palozoic "t comes to an end1 b z already rem>k$ !re is no m>k$ & sudd5 *ange to *>act]ise x4 ,_h our classification be5 orig9ally f\nd$ on /udy ( ! ,indian ,rocks in/ead ( ^? ( ,brita91 & simil> t]ms adopt$1 ! l9e ( dem>cation betwe5 ,palozoic & ,mesozoic rocks w\ld probably h be5 drawn bel[ ! ,p]mo-,c>bonif]\s deposits1 & if x _h be5 bas$ on /udy ( o!r areas1 p]haps else:]e4 ,! palontological break is purely local1 & x is ( ! utmo/ importance t x %\ld be recognis$ z su*1 & t x %\ld n be consid]$ t division into ,palozoic & ,mesozoic implies "s great & widespread *ange :i* occurr$ betwe5 ! times cov]$ by ! deposits ( ea* ( ^! great divisions#ig4 ,footnote #ig3 ,! ,p]mian ,fossils ( ,brita9 are describ$ by ,pr(essor ,k+ 9 ! ,monographs ( ! ,palontographical ,society 7! ,bra*iopods by ,dr ,davidson 9 ! ,monographs ( ! same ,society74 ,= a g5]al acc\nt ( ! m>9e type ! /ud5t may consult ! second edition ( ,messrs ,m$licott & ,blan=d's ,geology ( ,india4 ,= in=mation conc]n+ ! ,p]mian volcanic rocks see ,sir ,a4 ,geikie's ,anci5t ,volcanoes ( ,great ,brita94 ,,*apt] ,,xxi4 ,,! ,,triassic ,,sy/em4 ,classification4 ,! t]m ,triassic has be5 appli$ to ^! rocks on acc\nt ( ! ?reefold division into :i* ^? ( ,g]many naturally fall4 ,^! ?ree divisions are3-- ,keup]1 ,mus*elkalk1 ,bunt]2 b above ! ,keup] b$s we f9d a gr\p ( deposits ( "s importance1 :i* %ew aff9ities ) bo? ,triassic & ,jurassic rocks1 :i* may be look$ ^u z true passage b$s1 ?\gh !y are g5]ally plac$ 9 ! ,triassic ,sy/em4 ,!y are kn[n z ,rhtic or locally 9 ,brita9 z ,p5>? ,b$s4 ,! ,mus*elkalk is usually consid]$ to be unrepres5t$ 9 ,brita91 & accord+ly ! ,briti% deposits may be1 & are usually gr\p$ z "u3-- ,rhtic or ,p5>? b$s ,keup] ,keup] ,m>ls ,keup] ,s&/ones ,mus*elkalk abs5t ,upp] ,r$ & ,mottl$ ,s&/ones ,bunt] ,bunt] ,pebble ,b$s ,l[] ,r$ & ,mottl$ ,s&/ones4 ,! ?reefold gr\p+ has be5 appli$ m or less univ]sally1 b :5 us$ outside ! nor?-we/ ,european area1 x loses its significance1 z ! conditions :i* enable "o to diff]5tiate ! rocks ( ! ?ree divisions 7 naturally only preval5t ov] a limit$ area4 ,description ( ! /rata4 ,! ,briti% ,triassic rocks possess a c]ta9 sam5ess z reg>ds _! g5]al *>act]s1 consi/+ ma9ly ( me*anical s$im5ts col\r$ r$ by p]oxide ( iron1 ) occasional *emical precipitates ( rock-salt & gypsum4 ,!y h a wid] di/ribution ov] ,brita9 ?an h ! ,p]mian rocks1 & ! li?ological *>act]s ( ! diff]5t subdivisions d n z a rule v>y to a rem>kable degree :5 trac$ lat]ally4 ,! diff]5ces 9 detail 9 ! *>act]s ( ! v>i\s deposits are notewor?y1 & an explanation ( ! exact orig9 ( "s ( ^! abnormal deposits :i* w satisfy ev]yone is n yet =?com+4 ,leav+ ! details out ( consid]ation = ! mom5t1 & look+ at ! g5]al aspect ( ! deposits1 ! preval5ce ( conditions g5]ally simil> to ^? :i* exi/$ ov] ! ,briti% ,isles 9 ! prec$+ ,p]mian p]iod is decid$ly indicat$ by ! nature ( ! /rata1 ?\gh ! cont95tal conditions appe> to h be5 m widely e/abli%$ ov] our area1 z %ewn by ! g5]al abs5ce ( any calc>e\s deposits resembl+ ! ,magnesian ,lime/one4 ,we f9d *emical precipitates1 millet-se$ s&/ones1 & scree-l breccias 9 ! ,briti% ,triassic rocks z well z 9 ^? ( ,p]mian age1 & ! paucity ( a m>9e inv]tebrate fauna 9 ! ,triassic rocks ( ,brita9 is ev5 m app>5t ?an 9 ! ,p]mian /rata4 ,x is only at ! extreme close ( ! ,triassic p]iod1 dur+ ! deposition ( ! rocks :i* are admitt$ on all h&s to be ( ,rhtic age1 t we note ! incom+ ( ^? m>9e conditions ov] our area1 :i* prevail$ s ext5sively1 ) few local exceptions1 dur+ ! rema9d] ( ! ,mesozoic & ! e>ly "p ( ,t]ti>y times2 ! ,rhtic b$s1 9 fact1 m>k ! comm5cem5t ( ! ?ird m>9e p]iod4 ,ref]r+ to ! /rata 9 fur!r detail1 we may proce$ to consid] ! "* ( ! diff]5t subdivisions 9 ! ord] ( _! =mation1 comm5c+ z usual ) ! olde/4 ,! ,bunt] deposits re/ 9 places ^u ^? ( ,p]mian age ) an uncon=mity at ! junction1 b z ^! uncon=mities occur frequ5tly among ! ,briti% ,triassic rocks1 x is d\btful :e!r ?is uncon=mity m>ks m ?an v local *ange ( physical conditions4 ,! l[] & upp] divisions ( ! ,bunt] s&/one consi/ ( false-b$d$ r$ & v>iegat$ s&/ones1 & !re is no great difficulty 9 expla9+ _! =mation 9 des]t areas ) tracts ( wat]1 b ! great *ange :i* m>ks ! appe>ance & disappe>ance ( ! middle division1 ! ,bunt] pebble b$s1 requires "s explanation1 = ! contra/ betwe5 ! li?ological *>act]s ( ! rocks ( ?is division & ^? ( ! rocks app]ta9+ to ! prec$+ & succe$+ division is v m>k$4 ,! matrix diff]s1 b ! ma9 diff]5ce is ! abundance ( pebbles1 mo/ly ( fairly uni=m size1 well r\nd$1 & l>gely consi/+ ( liv]-col\r$ qu>tzite4 ,mu* diff]5ce ( op9ion exi/s z to ! exact orig9 ( ^! pebble b$s1 & ! s\rce ( ! pebbles1 b )\t ent]+ into ?is vex$ "q1 x may be rem>k$ t ! ag5cy ( riv]s has be5 some:at g5]ally invok$ to acc\nt = _! transport1 & ! conditions dur+ _! accumulation ne$ n h be5 v diff]5t f ^? :i* are n[ f\nd 9 nor!rn ,india :]e ! torr5tial riv]s ( ! s\? side ( ! ,himalayan *a9s deb\* ^u ! pla91 & spread an abundant deposit ( well-worn pebbles ov] ! f9] silts :i* 7 previ\sly laid d[n !reon4 ,! junction ( ! ,bunt] & ,keup] b$s requires a %ort notice4 ,x is usually if n always an uncon=mable "o 9 ,brita91 & x is g5]ally assum$ t ! abs5ce ( ! ,mus*elkalk ( ! ,cont95t is due to ! pres5ce ( l& und]go+ d5udation 9 ,brita9 dur+ ! "t :5 ! ,mus*elkalk 0 else:]e deposit$1 ?\gh x is q possible t ! ,mus*elkalk epo* is repres5t$ 9 ,brita9 n only by ! "t :i* elaps$ :5 ! uncon=mity 0 be+ impress$ on ! rocks1 b also dur+ ! true deposition ( ! upp] "p ( ! ,bunt] b$s1 or ! l[] "p ( ! ,keup]1 or bo?4 ,! ,keup] s&/ones & m>ls conta9 a great developm5t ( *emical deposits1 ( millet-se$ s&s1 & ( _m o!r features po9t+ to des]t conditions1 su* z sun-cracks1 tracks ( animals impress$ ^u a rapidly dry+ surface1 & pseudomorphs ( mud aft] rock salt 9 ! =m ( cubes & hopp]-cry/als2 fur!rmore we f9d ! scree-l breccias at diff]5t horizons ( ! ,keup] b$s :]e !y abut aga9/ ! old ,m5dip ridge compos$ l>gely ( m\nta9-lime/one :i* furni%$ ! fragm5ts1 z 0 ! case ) ! brockrams abutt+ aga9/ ! ,p5n9e ridge4 ,x mu/ be not$ t ! *emical precipitates ( ,triassic age consi/ ( ! less soluble sub/ances dissolv$ 9 ocean wat]1 namely1 gypsum & rock salt1 :il/ ! m deliquesc5t pota% & magnesia salts are n repres5t$ 9 ,brita94 ,turn+ to ^! cont95tal b$s1 we get evid5ce ( a g5]al approa* to op5 sea conditions z we pass away f ,brita9 9 a s\?-ea/]ly direction z r\ghly %ewn 9 ! foll[+ diagram 7fig4 #bb71 :]e ,b repres5ts ! ,bunt] b$s1 ,m ! ,mus*elkalk1 & ,k ! ,keup]4 ,illu/ration3 ,fig4 #bb4 ,x w be se5 t ! me*anical s$im5ts gradually die out & become replac$ by calc>e\s mat]ial z "o passes f ,brita9 t[>ds ,switz]l&2 ! ,mus*elkalk is v ?9 9 ! ea/ ( ,france & ?ick5s out 9 ,g]many1 :ile 9 ,switz]l& ,keup]1 ,mus*elkalk & ,bunt] are alike l>gely repres5t$ by calc>e\s deposits1 & ! me*anical deposits are *iefly argillace\s1 ! only important s&/one be+ situat$ at ! extreme base ( ! ,bunt] s]ies4 ,! m>9e developm5t ( ! ,triassic sy/em is naturally ! "o :i* is mo/ widely spread1 ?\gh full appreciation ( its importance has only tak5 place z ! result ( rese>*es 9 di/ant climes ( rec5t ye>s4 ,x is f\nd 9 s\!rn ,europe1 9 ,spitsb]g51 9 consid]able tracts ( ,asia1 includ+ ,india1 & along ! ,pacific coa/ region ( ,nor? ,am]ica1 & ev]y:]e possesses mu* ! same *>act]s4 ,x w be se5 f ! above rem>ks t ! physical conditions :i* prevail$ 9 ! cont95tal area ( ,triassic times :i* is n[ p>tly occupi$ by ! ,briti% ,isles are mo/ closely repres5t$ by ^? ( ! des]t regions ( c5tral ,asia1 hemm$ 9 by ! m\nta9 ranges :i* int]cept ! vap\r-lad5 w9ds ( ! oceans1 & cause !m to precipitate ! great bulk ( _! vap\r on ! seaw>d slopes ( ! m\nta9s1 s t !y bl[ ov] ! des]ts z dry w9ds1 caus+ ! fall ( any l>ge am\nt ( ra9 to be a r>e ?\gh by no means unkn[n ev5t 9 ! des]t regions4 ,flora & ,fauna ( ! ,p]iod4 ,! ,triassic flora is ess5tially simil> to t ( ! high] ,p]mian /rata1 ?\gh _m ( ! g5]a are diff]5t4 ,! inv]tebrate fauna ( ! ,briti% deposits is1 z might be expect$1 v poor until ! b$s ( ! ,rhtic s]ies are rea*$4 ,9 ! b$s bel[ ! ,rhtics1 ! pr9cipal inv]tebrate rema9s are ! te/s ( ! cru/acean g5us ,e/h]ia1 ?\gh a few obscure lamellibran* %ells h be5 record$4 ,! v]tebrate fauna is ( great int]e/4 ,a numb] ( fi%es h be5 f\nd1 ! mo/ rem>kable ( :i* is ! g5us ,c]atodus1 occurr+ 9 ! ,rhtic b$s ( ,brita9 & l[] ,triassic /rata ( =eign c\ntries4 ,x is closely relat$ to ! ,b>ramunda ( ! ,que5sl& riv]s belong+ to ! ord] ,dipnoi4 ,z 9 ! ,p]mian /rata1 abundance ( ,labyr9?odont amphibians h be5 discov]$1 & ! reptiles belong to ! ord]s ,anomodontia & ,rhyn*ocephalia4 ,9 ! ,rhtic b$s ( ,brita9 & 9 /ill l[] ,triassic b$s abroad ! ord]s ,i*?yopt]ygia & ,sauropt]ygia 7repres5t$ by ,i*?yosaurus & ,plesiosaurus7 are f\nd4 ,! ,triassic rocks also yield ! e>lie/ kn[n mammals1 ! be/ kn[n1 ,microle/es1 occurr+ 9 ! ,triassic rocks ( ,brita9 & ! ,cont95t4 ,^! mammals are n[ plac$ 9 a subclass ,meta!ria ( ! ord] ,monotremata4 ,! m>9e inv]tebrate fauna ( ! normal ,triassic rocks pres5ts "s po9ts ( consid]able int]e/4 ,z already rem>k$1 ! fauna may be look$ ^u z a passage fauna betwe5 t ( ,palozoic & t ( ,mesozoic times1 ! numb] ( ,palozoic =ms :i* pass into ! ,trias be+ approximately comp>able ) ^? :i* appe> "h & range upw>ds into high] ,mesozoic /rata4 ,?is may be well se5 by exam9+ ! table giv5 9 ,*apt] ,,xxi4 ( ! ,second ,edition ( ,sir ,*>les ,lyell's ,/ud5t's ,elem5ts ( ,geology1 9 :i* ?ree columns %ew ! g5]a ( ,mollusca common to old] rocks1 ^? *>act]i/ic ( ! ,trias1 & ^? common to new] rocks4 ,among/ ! fir/ are ,or?oc]as1 ,bactrites1 ,loxonema1 ,mur*isonia1 & ,euomphalus1 9 ! second column are ,c]atites1 ,halobia 7,daonella71 ,kon9ck9a1 & ,myophoria1 & 9 ! ?ird1 ,ammonites1 ,c]i?ium1 ,opis1 ,plicatula & ,!cidium#ih4 ,footnote #ih3 ,x has be5 se5 t "s ( ! ,ammonites appe> e>li]1 namely1 9 ,p]mian /rata4 ,myophoria is extremely abundant 9 ! ,trias1 b ranges into new] /rata4 ,! ,ammonites are l>gely utilis$ 9 ! case ( ! ,mesozoic /rata = sep>ation ( ^! /rata into zones1 ea* zone be+ *>act]is$ by "s species ( ,ammonite1 & ! rese>*es ( ,mojsisovics h prov$ t ?is zonal subdivision1 long adopt$ = ,jurassic rocks1 is also applicable to ^? ( ,triassic age#ii4 ,he gives ! foll[+ table ( ! classification ( ! ,triassic rocks ( ! ,m$it]ranean ,prov9ce1 :i* is reproduc$1 z x is f\nd$ ^u ,palontological evid5ce1 & w probably be widely adopt$4 ,footnote #ii3 von ,mojsisovics1 ,dr ,e41 ,fauni/is*e ,ergebnisse aus d] ,unt]su*ung d] ,ammone5-faun5 d] ,m$it]ran5 ,trias4 ,abh&l4 d] k4 k4 ,geologis*4 ,rei*san/alt1 ,,vi4 ,b& #b ,ab!ilung4 ,vi5na1 #ahic4 ,s]ies ,zonal ,divisions ---------------------------------------- ------------------------------- ,rhtic #a4 ,zone ( ,avicula ,contorta ---------------------------------------- ------------------------------- #b4 ,zone ( ,sir5ites ,argonautae ,upp] ,juvavic #c4 ,zone ( ,p9nacoc]as ,mett]ni*i ,juvavic ,middle ,juvavic #d4 ,zone ( ,cyrtopleurites bicr5atus #e4 ,zone ( ,cladiscites rub] ,l[] ,juvavic #f4 ,zone ( ,sag5ites ,giebeli ---------------------------------------- ------------------------------- ,upp] ,c>nic #g4 ,zone ( ,tropites subbullatus ,c>nic ,middle ,c>nic #h4 ,zone ( ,tra*yc]as ,aonoides ,l[] ,c>nic #i4 ,zone ( ,tra*yc]as ,aon ---------------------------------------- ------------------------------- ,upp] ,noric #aj4 ,zone ( ,protra*yc]as ,noric ,ar*elaus ,l[] ,noric #aa4 ,zone ( ,protra*yc]as ,curionii ---------------------------------------- ------------------------------- ,upp] ,mus*elkalk #ab4 ,zone ( ,c]atiles tr9odosus ,mus*elkalk ,l[] ,mus*elkalk #ac4 ,zone ( ,c]atiles b9odosus ---------------------------------------- ------------------------------- ,bunts&/e9 ,w]f5] ,s*i*t5 #ad4 ,zone ( ,tirolites ,cassianus ---------------------------------------- ------------------------------- ,,*apt] ,,xxii4 ,,! ,,jurassic ,,sy/em4 ,! ,jurassic rocks 7 =m]ly sep>at$ on acc\nt ( diff]5ces ( li?ological "* into ,oolites & ,lias1 b x 0 app>5t t ! ,oolites 7 m important ?an ! ,lias1 & a f\rfold division 0 made into3-- ,upp] or ,portl& ,oolites ,middle or ,ox=d ,oolites ,malm ,l[] or ,ba? ,oolites ,dogg] ,lias4 ,! ,lias /rata h also be5 spok5 ( z ! ,black ,jura1 ! ,l[] ,oolites & "p ( ! ,ox=d ,oolites z ,br[n ,jura1 & ! re/ ( ! ,ox=d ,oolites ) ! ,portl& ,oolites z ,:ite ,jura4 ,z ! outcome ( a detail$ /udy ( ! faunas ( ! ,jurassic rocks1 a fur!r subdivision has be5 made1 p>tly bas$ ^u ! orig9al ,briti% s]ies1 b ! divisions are def9$ ) great] accuracy1 s t !y are applicable ov] wid] areas4 ,!y are z foll[s3-- ,purbeckian ,upp] ,oolites ,portl&ian ,kimm]idgian ,corallian ,middle ,oolites ,ox=dian ,callovian ,l[] ,oolites ,ba?onian ,bajocian ,to>cian ,lias ,liassian ,s9emurian4 ,_m ( ^! s]ies h be5 /ill f>!r subdivid$ into small] /ages1 & ! :ole diff]5tiat$ into a numb] ( zones *>act]is$ by diff]5t =ms ( ,ammonites4 ,dr ,e4 von ,mojsisovics gives ?irty-two ,ammonite zones1 ( :i* f\rte5 occur 9 ! ,lias1 eight 9 ! ,l[] ,oolites1 six 9 ! ,middle ,oolites1 & f\r 9 ! ,upp] ,oolites4 ,*>act]s ( ! /rata4 ,! :ole ( ! ,jurassic rocks & also ^? ( ,l[] ,cretace\s age may be reg>d$ z hav+ be5 deposit$ dur+ ! fir/ %all[ wat] phase ( ! ?ird m>9e p]iod1 b ?is %all[ wat] phase is repres5t$ by /rata :i* are v>i$ ow+ to num]\s m>9e *anges result+ 9 ! production ( l& at times1 & e/u>9e conditions1 %all[ wat]1 m>9e conditions1 & some:at deep] sea conditions respectively at o!r times1 & accord+ly ! /rata ( ! ,briti% ,isles v>y greatly :5 trac$ lat]ally4 ,t ! uplifts ( ! ,p]mo-,triassic p]iods produc$ "s effect on ! nature & di/ribution ( ! ,jurassic rocks is c]ta91 b x is n q cle> h[ f> ! ridges produc$ by ^! uplifts 7 subm]g$ & d5ud$ dur+ ! deposition ( ! ma9 portion ( ! ,jurassic /rata4 ,view$ broadly1 ! ,jurassic rocks ( ,brita9 may be reg>d$ z consi/+ ( ?ree great clay deposits1 ! ,lias1 ,ox=d & ,kimm]idge ,clays1 alt]nat+ ) ! deposits ( v>iable li?ological *>act]s1 :i* compose ! ,bajocian1 ,ba?onian1 ,corallian1 ,portl&ian & ,purbeckian subdivisions4 ,?is ess5tially argillace\s "* ( a l>ge "p ( ! deposits ( ,jurassic age is (t5 ov]look$1 z1 ow+ to _! sam5ess & ! comp>ative paucity ( organisms con/itut+ ! faunas 9 ! clays1 _! description 9 text-books c be giv5 at mu* %ort] l5g? ?an t ( ! m v>iable & highly fossilif]\s deposits :i* sep>ate ! clays4 ,! foll[+ figure 7,fig4 #bc7 r\ghly repres5ts ! nature ( ! diff]5t divisions ( ! rocks ( ?is sy/em :5 trac$ across ,engl& f s\?-we/ to nor?-ea/4 ,illu/ration3 ,fig4 #bc4 ,v]tical scale3 #a 94 ab\t #ajjj feet4 ,x w be se5 t ! greate/ v>iations 9 li?ological "* occur 9 ! ,ba?onian & ,bajocian b$s1 & x w be ( int]e/ to give "s acc\nt ( ! pr9cipal v>iations & to attempt to acc\nt = !m4 ,9 s do+ x w be conv5i5t to consid] ! f\r major divisions ( ! ,jurassic rocks sep>ately1 & to ent] into p>ticul>s conc]n+ ! local classification appli$ to ! rocks ( ^! divisions4 ,! ,lias4 ,! ,briti% ,lias deposits are divid$ into ! ,l[] ,lias1 ! ,m>l/one1 & ! ,upp] ,lias correspond+ 9 g5]al t]ms only ) ! ,s9emurian1 ,liassian1 & ,to>cian4 ,! ,m>l/one is sep>at$ f ! ,upp] & ,l[] ,lias on acc\nt ( ! great] p]c5tage ( c>bonate ( lime :i* x conta9s1 s t ! b&s ( argillace\s lime/one are mu* m m>k$ 9 ! ,m>l/one ?an 9 ! upp] & l[] divisions1 :i* consi/ *iefly ( clay4 ,! ?ree divisions possess v mu* ! same *>act]s ?r\gh\t ! c\ntry1 ?\gh ! pres5ce ( ! ,m5dip ridge & its cont9uation b5ea? ,london is m>k$ by ! att5uation ( ?is & succe$+ /rata1 & by ! conglom]atic "* ( "s ( ! ,liassic /rata :]e !y abut aga9/ x4 ,! ,briti% ,lias1 z a :ole1 seems to h be5 deposit$ 9 a fairly %all[ sea at no great di/ance f ! l&4 ,x passes d[n con=mably into ! ,rhtic b$s1 inde$ ! zone ( ,ammonites 7,aegoc]as7 planorbis1 ref]r$ by ,briti% geologi/s to ! ,l[] ,lias is includ$ by "s cont95tal writ]s ) ! ,rhtic b$s1 & ! plane ( dem>cation "h z 9 o!r cases is conv5tional4 ,! ,l[] ,oolites4 ,( all ! ,briti% /rata1 ^! p]haps cause mo/ tr\ble to ! le>n]1 on acc\nt ( ! diff]5t nom5clature appli$ to ! rocks 9 diff]5t p>ts ( ,engl&1 & ! rapid v>iations 9 li?ological "*1 :5 ! b$s are trac$ lat]ally4 ,! foll[+ divisions are usually adopt$ = ! b$s ( ! s\?-we/]n c\nties :]e ! mo/ m>k$ m>9e developm5t occurs3-- ,cornbra%1 ,=e/ ,m>ble1 ,great ,oolite 7) ,brad=d ,clay71 ,full]'s ,e>?1 ,inf]ior ,oolite4 ,( ^! divisions1 ! upp]mo/ "o1 ! ,cornbra%1 ?\gh ?91 reta9s its *>act]s ) great con/ancy across ! isl&4 ,( ! o!rs ! ,=e/ ,m>ble may be look$ ^u z a local developm5t ( ! upp] portion ( ! ,great ,oolite1 & ! ,full]'s ,e>? is a local deposit1 s t ! ,inf]ior ,oolite & ,great ,oolite con/itute ! important divisions ( ! ,l[] ,oolites4 ,! v>iations 9 ! *>act]s ( ! rocks may be be/ %[n 9 tabul> =m4 ---------------------------------------- ------------------------------- ,gl\ce/]%ire1 ,s\? ,n4 c4 ,nor?ampton%ire ,nor?ampton%ire ,york%ire & ,l9coln ---------------------------------------- ------------------------------- ,cornbra% ,cornbra% ,cornbra% ,cornbra% ---------------------------------------- ------------------------------- ,great ,oolite ,great ,oolite ,great ,oolite ,clay 7,upp] "p7 ,great ,oolite ,upp] ,lime/one ,upp] ,e/u>9e ,nor?ampton%ire ,e/u>9e 444444444444444 4444444444444444 44444444444444444 4444444444444444 ,s]ies ,s]ies ,l9coln%ire ,sc>bro' ,lime/one ,lime/one ,s&s ,middle ,e/u>9e ,s]ies ,inf]ior ,oolite ,l[] ,e/u>9e ,millepore ,oolite ,s]ies ,l[] ,e/u>9e ,s]ies ---------------------------------------- ------------------------------- ,upp] ,lias ,upp] ,lias ,upp] ,lias ,upp] ,lias ---------------------------------------- ------------------------------- ,! dott$ l9e %[s r\ghly ! division betwe5 ,ba?onian & ,bajocian4 ,! *anges may be expla9$ v simply if we leave out ( acc\nt = ! mom5t ! developm5t ( ,l9coln%ire ,lime/one1 ) its equival5t ! ,sc>bro' ,lime/one1 & ! ,millepore s]ies4 ,! b$s 9 ,gl\ce/]%ire & o!r s\?-we/]n c\nties are ess5tially m>9e2 :il/ 9 ,nor?ampton%ire & ,l9coln%ire e/u>9e conditions set 9 aft] ! deposition ( ! ,upp] ,lias1 & cont9u$ ?r\gh\t ! deposition ( ! ,bajocian & ,l[] ,ba?onian b$s1 be+ replac$ by m>9e conditions dur+ ! =mation ( ! ,upp] ,ba?onian /rata1 & /ill fur!r nor? 9 ,york%ire ! e/u>9e conditions g5]ally prevail$ ?r\gh\t ,bajocian & ,ba?onian times4 ,^! *anges po9t to ! exi/5ce ( l& t[>ds ! nor?4 ,! g5]al simplicity is modifi$ by tempor>y preval5ce ( m>9e conditions twice ov] 7dur+ ! deposition ( ! ,millepore ,oolite & ! ,sc>bro' ,lime/one7 9 ,york%ire1 & once 7dur+ ! deposition ( ! ,l9coln%ire ,lime/one7 9 ,l9coln%ire4 ,c]ta9 local deposits h n be5 notic$1 b two ( !m m]it brief ref]5ce4 ,at ! base ( ! ,great ,oolite ( ,ox=d%ire is an e/u>9e deposit ( f9ely lam9at$ me*anical s$im5t mix$ ) calc>e\s matt] kn[n z ! ,/onesfield ,slate1 especially int]e/+ on acc\nt ( its fossils1 :ile a b$ ) simil> li?ological *>act]s b ) a diff]5t fauna occurr+ at ! base ( ! ,l9coln%ire ,lime/one 7( ,bajocian age7 is t]m$ ! ,collywe/on ,slate4 ,nei!r ( ^! deposits is a slate 9 ! true s5se ( ! ^w1 z !y h n be5 affect$ by cleavage subsequ5tly to _! accumulation1 b ea* has be5 some:at ext5sively us$ = ro(+ purposes4 ,! ,middle ,oolites are mu* less complicat$ ?\gh consid]able v>iations arise ) respect to ! ,corallian ,rocks4 ,! ,ox=dian ) ,callovian consi/ *iefly ( clay1 ?\gh ! ,callovian ( ! s\? ( ,engl& is repres5t$ by calc>e\s s&/one1 ) a peculi> fauna :i* seems to be repres5t$ 9 ! l[] "p ( ! ,ox=d ,clay fur!r nor?1 ?\gh ?is ,callovian fauna has n be5 ev]y:]e recognis$4 ,! ,corallian ( ! s\!rn c\nties consi/s ( lime/ones ) calc>e\s grits1 ! lime/ones be+ (t5 l>gely compos$ ( ! rema9s ( reef-build+ corals1 & a simil> developm5t ( ! rocks ( ?is s]ies is f\nd 9 ,york%ire1 :ile a local developm5t ( ! same "* is f\nd at ,upw>e 9 ,cambridge%ire1 ?\gh 9 ! o!r p>ts ( ! ,f5l& c\nties ! ,corallian is repres5t$ by an argillace\s deposit ) ,corallian fossils kn[n z ! ,amp?ill ,clay4 ,! ,upp] ,oolites h a tol]ably con/ant base1 ! ,kimm]idge ,clay1 usually consi/+ ( lam9at$ bitum9\s argillace\s mat]ial1 b ! ,portl&ian & ,purbeckian divisions v>y greatly1 & are only locally develop$1 ?\gh _! abs5ce 9 "s p>ts ( c5tral ,engl& is no d\bt due to uncon=mity4 ,! ,portl&ian rocks ( ! s\? ( ,engl& consi/ ( lime/ones & s&/ones :i* pass fur!r nor?w>d into %all[] wat] me*anical deposits (t5 *>g$ ) iron hydrate1 & ! b$s disappe> 9 ,ox=d%ire4 ,! ,purbeckian rocks ( ! s\? are also limit$ z reg>ds area ( exposure3 !y consi/ ( e/u>9e deposits ) "s t]re/rial accumulations ( ! nature ( old surface soils4 ,repres5tations ( ! ,portl&ian & ,purbeckian b$s are f\nd 9 ,l9coln%ire & ,york%ire1 z ar5ace\s deposits 9 ! =m] c\nty & argillace\s ones 9 ! latt]4 ,bo? are m>9e deposits ( a nor!rn type1 develop$ else:]e 9 nor!rn ,european & circumpol> regions1 & 9 ^! c\nties we f9d a complete passage f ! ,jurassic rocks ?r\gh ! ,cretace\s rocks1 b ! exact l9es ( dem>cation betwe5 ! diff]5t s]ies ( ! passage b$s are difficult to def9e4 ,! =eign ,jurassic rocks ( ,europe & ( "s p>ts ( ,asia /rongly resemble 9 g5]al *>act]s ^? :i* h be5 describ$ above z occurr+ 9 ,brita94 ,"o ( ! mo/ rem>kable features ( ! ,jurassic rocks z a :ole1 is ! abs5ce ( ! ,lias ov] wide areas1 ! cont95tal p]iod :i* 9 ,brita9 exi/$ 9 ,p]mo-,triassic times is else:]e frequ5tly replac$ by "o ( ,liassic age4 ,! ,jurassic & ,cretace\s rocks are ( int]e/ on acc\nt ( ! evid5ce :i* !y supply z to ! exi/5ce ( climatic zones 9 ^! p]iods1 :i* run fairly p>allel ) ^? at pres5t exi/+4 ,! late ,dr ,neumayr 9 a pap] already cit$ divides ! _w dur+ lat] ,mesozoic times into f\r di/9ct climatic zones1 equatorial1 nor? & s\? temp]ate & boreal zones 7! correspond+ au/ral zone is n kn[n ow+ no d\bt to ! ext5sive sea ( ,s\? ,pol> regions & our g5]al ignorance ( its l&s74 ,9 ,europe ! ,m$it]ranean ,prov9ce belongs to ! equatorial zone1 ! ,middle ,european to ! ,nor? temp]ate zone1 & ! ,russian or ,boreal to ! ,boreal zone4 ,! la/-nam$ is m>k$ p>tly by negative *>act]s1 ! abs5ce ( c]ta9 ,ammonite-g5]a & ( coral reefs be+ noticeable1 :il/ ! lamellibran* ,aucella is v frequ5t4 ,9 ! ,nor? temp]ate zone1 c]ta9 ,ammonite g5]a z ,aspidoc]as & ,oppelia are abundant & !re are also ext5sive coral-reefs4 ,! ,equatorial zone is m>k$ by ! ,ammonite-g5]a ,phylloc]as & ,lytoc]as & by ! ,diphya gr\p ( ,t]ebratul4 ,x is ( special int]e/ to note t ! fauna ( ! ,s\? temp]ate be>s clos] relation%ip to t ( ! ,nor? temp]ate ?an to t ( ! int]m$iate ,equatorial zone4 ,jurassic floras & faunas4 ,! ,jurassic flora is v simil> 9 its *>act]s to t ( ! ,l[] ,cretace\s rocks1 & ! two tak5 toge!r af=d a decid$ contra/ ) t ( lat] ,palozoic times1 & also ) t :i* succe$s !m 9 ! ,upp] ,cretace\s rocks1 :i* be>s a m>k$ resemblance to ! exi/+ flora4 ,cycads pr$om9ate1 accompani$ by conif]s1 & a fair numb] ( f]ns & ,equisetace4 ,! ,jurassic fauna is specially notewor?y on acc\nt ( ! "* ( ! v]tebrata1 b "s notice ( ! inv]tebrates mu/ also be tak54 ,! abundance ( corals 9 ! ,temp]ate zones has already be5 po9t$ out1 b ! mollusca =m ! bulk ( ! inv]tebrate fauna1 lamellibran*s1 ga/ropods & cephalopods be+ all abundant2 ( ! la/-nam$ ! ammonites & belemnites contribute mo/ l>gely4 ,! v]tebrates include rema9s ( fi%es1 amphibia1 reptiles1 birds & mammals4 ,! ,jurassic reptilia furni% repres5tatives ( "s mod]n ord]s z ! ,*elonia & ,crocodilia1 b ! mo/ important ord]s are ess5tially *>act]i/ic ( lat] ,mesozoic times & _! repres5tatives ab\nd 9 ! ,jurassic /rata4 ,^! are ! ,sauropt]ygia 7includ+ ! ,plesiosaurs71 ! ,i*?yopt]ygia 7includ+ ! ,i*?yosaurs71 ! ,d9osauria1 & ! ,pt]osauria commonly kn[n z ,pt]odactyls4 ,no birds h hi!rto be5 discov]$ 9 ! ,briti% ,jurassic rocks1 b ! ,sol5h(5 ,slate ( ,bav>ia 7( ,kimm]idgian age7 has furni%$ ! celebrat$ ,ar*opt]yx macrura1 :i* is n only plac$ 9 a family b also 9 an ord] by itself1 ! ord] ,saurur4 ,_m rema9s ( mammals h be5 extract$ f ! e/u>9e deposits ( ,/onesfield1 & ! old surface soils ( ! ,purbeckian b$s2 repres5tatives ( ! ,monotremata are furni%$ by ! ,plagiaulacid & ,tritylodontid1 ! =m] family conta9+ ! g5us ,plagiaulax ( ! ,purbeck ,b$s & ! latt]1 ,/]eogna?us ( ! ,/onesfield slate4 ,! ,m>supialia are repres5t$ by ! ,amphi!rid1 ,spalaco!rid & ,triconodontid4 ,"s =ms h be5 ref]r$ to ! ,insectivora1 b !re is /ill disagreem5t conc]n+ ! correctness ( ?is ref]5ce4 ,be=e dismiss+ ! subject ( ! ,jurassic fossils1 att5tion may be call$ to a feature :i* has be5 frequ5tly comm5t$ ^u1 namely1 ! g5]al resemblance ( ! flora & fauna ( ,jurassic times to ! mod]n ,au/ralian fauna & flora4 ,! explanation :i* has be5 (f]$ to acc\nt = ?is resemblance has be5 giv5 9 a prec$+ *apt]1 :]e x 0 /at$ t ,mr ,a4 ,r4 ,wallace consid]s1 aft] review ( ! geological & biological evid5ce1 t ,au/ralia 0 sev]$ f ! adjo9+ cont95tal l&s 9 ,mesozoic times1 & t ! high] =ms ( life :i* on ! l>g] cont95ts h replac$ ! e>li] & l[] =ms h n succe$$ 9 obta9+ a foot+ 9 ,au/ralia1 :i* !re=e furni%es u ) a local survival ( a once widespread fauna4 ,9 connection ) ?is matt] ! actual exi/5ce ( ! g5us ,trigonia 7a =m peculi>ly abundant 9 ,jurassic /rata & *>act]i/ic ( ,mesozoic /rata 9 ,brita97 9 ! ,au/ralian sea is ( consid]able int]e/4#ajj ,footnote #ajj3 ,a good acc\nt ( ! ,briti% ,jurassic rocks w be f\nd 9 ,mr ,h4 ,b4 ,woodw>d's ,memoir on ,! ,jurassic ,rocks ( ,brita94 ,mem4 ,geol4 ,survey1 #ahic--4 ,,*apt] ,,xxiii4 ,,! ,,cretace\s ,,sy/em4 ,classification4 ,! rocks ( ! ,cretace\s sy/em are conv5i5tly divid$ into ,upp] & ,l[] ,cretace\s4 ,! foll[+ classification has be5 widely us$ = ! ,briti% deposits1 & is f\nd$ on li?ological *>act]s3 ,upp] ,*alk ) fl9ts ,middle ,*alk ) few fl9ts ,*alk ,upp] ,l[] ,*alk )\t fl9ts ,cretace\s ,*alk ,m>l ,upp] ,gre5s& ,gault ,l[] ,gre5s& ,l[] ,weald5 ,cretace\s ,ha/+s s&s ,z ! result ( exam9ation ( ! faunas1 a m g5]ally applicable classification has be5 e/abli%$ & is n[ l>gely adopt$4 ,x is z foll[s3 ,danian ,s5onian ,upp] ,cretace\s ,turonian ,c5omanian ,albian ,aptian ,l[] ,cretace\s4 ,neocomian ,9 ?is classification ! ,neocomian practically repres5ts ! ,weald5 & ,ha/+s b$s1 ! ,aptian ! ,l[] ,gre5s& & ! ,albian ! ,gault1 plac$ accord+ to ?is classification 9 ! ,l[] ,cretace\s1 :ile ! ,upp] divisions repres5t ! /rata above ! ,gault1 consi/+ ess5tially ( ,*alk 9 ,engl&4 ,description ( ! ,/rata4 7i7 ,! ,neocomian & ,aptian ,b$s4 ,9 ! s\? ( ,engl& ! ,l[] ,cretace\s b$s succe$ ! ,jurassic rocks ) little or no break1 & ! type ( ! l[] b$s is simil> to t ( ! b$s deposit$ dur+ ! ,purbeck age1 consi/+ ( e/u>9e deposits ( v>iable *>act]s1 *iefly ar5ace\s bel[ 7! ,ha/+s s&s7 & argillace\s above 7! ,weald5 s]ies71 ?\gh impure lime/ones are f\nd1 l>gely compos$ ( ! %ells ( ! fre%wat] ,palud9a1 & mu* iron/one is develop$ 9 places4 ,at ! close ( ,neocomian times1 ! fre%wat] conditions 9 s\!rn ,engl& 7 replac$ by m>9e conditions & ! ,l[] ,gre5s& /rata ) _! m>9e fauna 7 deposit$ 9 ! ,aptian sea4 ,! ,neocomian & ,aptian b$s ?9 out we/w>d1 & mu* m rapidly to ! nor?w>d1 s t bo? divisions disappe> aga9/ ! n[ buri$ ridge :i* =ms a cont9uation ( ! ,m5dip axis4 ,nor? ( ?is !y appe> 9 ano!r =m4 ,at fir/ ! highe/ ,aptian b$s alone are develop$ z %ore deposits4 ,pass+ into ,norfolk l[] b$s come 9 until 9 ,l9coln%ire we get a complete developm5t ( ! ,neocomian & ,aptian b$s ) a m>9e facies1 ?\gh ( fairly %all[ wat] "*1 :il/ 9 ,york%ire ! two divisions are repres5t$ by a deep] wat] clay1 =m+ ! ,upp] portion ( ! ,speeton s]ies4 ,!re is a cons5sus ( op9ion 9 fav\r ( ! ,neocomian b$s ( s\!rn ,brita9 hav+ be5 laid d[n 9 an e/u>y ( a riv] fl[+ f ! we/ ov] a cont95t n[ de/roy$4 ,to ! nor? ( ?is riv] /ood ! ,london ridge ( ! ,palozoic rocks1 ! nor!rn bord]s ( :i* =m$ ! coa/ l9e (f :i* 7 deposit$ ! s$im5ts ( ,neocomian & ,aptian ages :i* occur 9 nor!rn ,engl&4 ,be=e ! deposition ( ! ,albian b$s a consid]able upheaval ( "s p>ts ( ,brita9 occurr$1 & an uncon=mity sep>ates ! high] ,cretace\s b$s f old] /rata ( ,cretace\s & ,jurassic ages1 ?us complicat+ ! major phases by local *anges 9 ! *>act]s ( ! /rata4 7ii7 ,! ,albian & high] ,cretace\s ,b$s4 ,! comm5cem5t ( ! deep-wat] phase ( ! ?ird m>9e p]iod may be said to occur 9 ,albian times 9 ,brita91 rea*+ its maximum dur+ ! deposition ( ! *alk4 ,! exi/5ce ( a deep] sea t[>ds ! nor? ( ,engl& is indicat$ by ! *>act]s ( ! ,albian & new] /rata4 ,! ,albian b$s ( gault consi/ ( a /iff clay 9 s\!rn ,engl&1 replac$ by co>s] me*anical s$im5ts t[>ds ! we/4 ,z "o passes nor? f ! ,london ridge 7:i* ex]t$ its influ5ce 9 ,albian times1 aft] :i* x 0 f9ally buri$ 9 s$im5t7 ! gault ?9s out1 & becomes gradually replac$ by calc>e\s deposit :5 x is kn[n z ! r$ *alk :i* replaces ! gault 9 nor!rn ,norfolk1 ,l9coln%ire & ,york%ire4 ,a local uncon=mity sep>at+ ! *alk & gault 9 p>ts ( ,ea/ ,anglia po9ts to ano!r local uplift ) its accompany+ complications 9 ! *>act]s ( ! /rata4 ,aft] ! uplift _h ceas$1 g5]al depression mu/ h occurr$1 & ! v>i\s divisions ( ! *alk 7 accumulat$ 9 a fairly op5 sea1 ?\gh1 = reasons to be giv5 pres5tly1 ?is 0 probably ( no great lat]al ext5t1 save :5 unit$ ) ! op5 ocean1 probably 9 a mann] simil> to ! connexion betwe5 ! ,gulf ( ,mexico & ! ,atlantic4 ,! g5]al v>iations 9 ! li?ological *>act]s ( ! v>i\s memb]s ( ! ,cretace\s sy/em w probably be r5d]$ cle>] by ref]5ce to ! accompany+ diagram 7fig4 #bd7 repres5t+ ! v>iations :5 trac$ across ,engl& f s\? to nor?#aja4 ,footnote #aja3 ,= in=mation conc]n+ ! ,briti% ,cretace\s b$s1 see ,topley & ,fo/]1 ,geology ( ! ,weald1 ,mem4 ,geol4 ,survey1 #ahge2 ,bri/[ & ,/rahan1 ,geology ( ! ,isle ( ,wight1 ,mem4 ,geol4 ,survey1 #ahhi2 ,lamplugh1 ,on ! ,speeton ,clay1 ,q4 ,j4 ,g4 ,s41 vol4 ,,xlv4 p4 #ege1 & ,! ,speeton ,s]ies 9 ,york%ire & ,l9coln%ire1 ibid41 vol4 ,,lii4 p4 #agi2 ,b>rois ,re*]*es sur le ,t]ra9 ,crtac suprieur de l',anglet]re et d',irl&e1 ,lille1 #ahgf2 & v>i\s pap]s by ,messrs ,hill & ,jukes-,br[ne1 9 ! ,qu>t]ly ,j\rnal ( ! ,geological ,society & ,geological ,magaz9e ( rec5t ye>s4 ,= ! ,scot* deposits consult a pap] by ,pr(4 ,judd1 ,q4 ,j4 ,g4 ,s41 vol4 ,,xxxiv4 p4 #gcf1 & = ^? ( ,irel&1 see ,hume1 ,q4 ,j4 ,g4 ,s41 vol4 ,,lii4 p4 #edj4 ,illu/ration3 ,fig4 #bd4 ,*4 ,*alk4 ,al4 ,albian4 ,ap4 ,aptian4 ,n4 ,neocomian4 ,j4 ,jurassic4 ,! clue to ! physical geography ( ,brita9 dur+ ,cretace\s times is furni%$ to a consid]able ext5t by /udy ( ! =eign deposits4 ,9 ,nor!rn ,europe ! ,cretace\s b$s ( ,engl& are met ) 9 ,nor!rn ,france1 & !re ! *>act]s are g5]ally speak+ simil> to ^? ( our ,briti% deposits4 ,9 ,g]many %all[] wat] conditions prevail$1 ! l[] b$s gradually disappe>1 & ! upp] b$s are replac$ by me*anical s$im5ts ( v>i\s degrees ( co>s5ess1 becom+ on ! :ole co>s]1 z "o travels ea/w>d1 s t 9 ,saxony ! *alk is p>tly replac$ by ar5ace\s deposits 7! ',quad]' s&/ones7 :i* are responsible = ! rem>kable sc5]y ( ! ,elbe di/rict above ,dresd54 ,9 pass+ nor?w>ds1 indications ( simil> *ange are not$ 9 ! deposits ( ,d5m>k & ,scania1 :il/ to ! s\?1 we get a complete *ange 9 ! "* ( ! rocks1 aft] cross+ ! ,loire 9 ,france1 & a simil> *ange is obs]vable 9 di/ricts ly+ fur!r ea/4 ,fur!rmore1 z w be not$ m fully 9 a subsequ5t p>agraph1 ! "* ( ! ,upp] ,cretace\s flora indicates ! exi/5ce ( a l>ge tract ( l& ly+ to ! nor? & nor?-we/ ( ,europe1 s t x w\ld appe> t ! ,cretace\s rocks ( ,nor!rn ,europe 7 deposit$ 9 a gulf-l expansion ( a we/]n ocean1 b\nd$ on ! nor? by ,sc&9avia1 on ! we/ by ea/]n ,g]many1 & on ! s\? by a ridge runn+ ea/w>d f ! m\? ( ! ,loire#ajb4 ,we may speak ( ?is gulf z ! ,*alk gulf4 ,to ! s\? ( ! presum$ ridge ! "* ( ! /rata alt]s1 & also t ( ! includ$ organisms4 ,?is s\!rn type ( ,cretace\s rocks is "o :i* is v widely spread1 be+ f\nd 9 ,europe s\? ( ! ,loire1 & ( ! ,alps1 & 9 ,greece & ,turkey1 :ile x also occurs 9 ! nor!rn p>ts ( ,africa4 ,! b$s ( ?is type are traceable ?r\gh ,asia ,m9or into ,india & to ! %ores ( ! ,indian ,ocean1 indicat+ ! exi/5ce ( a widespread ,cretace\s ocean1 :i* is sometimes spok5 ( z ! ,hippurite-lime/one sea1 = reasons :i* w ev5tually appe>4 ,! deposits are l>gely =m$ ( h>d lime/one :i* is v diff]5t 9 its "* f ! s(t *alk ( ! nor!rn gulf4 ,footnote #ajb3 ,! read] w f9d ! exi/5ce ( ?is gulf ma9ta9$ & support$ by a consid]able mass ( detail 9 ,mr ,a4 ,r4 ,wallace's ,isl& ,life4 ,! climatic conditions :i* prevail$ dur+ ,cretace\s times 7 app>5tly simil> 9 mo/ respects to ^? ( ! prec$+ ,jurassic p]iod1 & z already /at$ ! climatic zones :i* ,neumayr def9$ = ,jurassic times are also ma9ta9$ by him to h exi/$ dur+ ! ,cretace\s p]iod4 ,! exi/5ce ( cold has sometimes be5 inf]r$ f ! pres5ce ( l>ge =eign blocks 9 ! *alk1 especially at its base1 b if ^! are due to ! transport1 !y might well be caus$ by masses ( float+ ice1 :i* are (t5 f\nd at consid]able di/ances f ! coa/ 9 temp]ate regions aft] ! break-up ( ! fro/ :i* succe$s an unusually h>d w9t]4 ,! flora & fauna are n sugge/ive ( sev]e conditions4 ,! ,cretace\s flora & fauna4 ,x has be5 not$ 9 ! la/ *apt] t ! gymnosp]m\s flora ( ! ,jurassic p]iod1 9 :i* cycads =m a consid]able p]c5tage ( ! :ole flora1 0 preval5t 9 ,l[] ,cretace\s times4 ,9 ! ,upp] ,cretace\s rocks ?is flora is replac$ by "o :i* consi/s to a l>ge ext5t ( dicotyl$on\s angiosp]ms4 ,^! are f\nd 9 ! ,upp] ,cretace\s rocks ( ,europe & ,nor? ,am]ica1 & z ! rese>*es ( botani/s indicate _! orig9 9 circumpol> regions1 _! arrival 9 ,europe is an additional argum5t 9 fav\r ( ! exi/5ce ( an ext5sive nor!rn cont95t1 s5d+ a prolongation to ! s\?w>d 9 ea/]n ,europe4 ,! inv]tebrate fauna be>s consid]able resemblance to t ( ,jurassic times1 & _m ( ! dom9ant ,jurassic g5]a are also f\nd 9 ,cretace\s rocks4 ,a mo/ int]e/+ feature is connect$ ) ! "* & geographical di/ribution ( ! ,ammonites4 ,9 ,europe !y are almo/ exclusively conf9$ to ! deposits ( ! nor!rn gulf1 & be=e _! f9al disappe>ance !y und]go _m *anges ( =m4 ,we f9d ! discoid spiral %ells ( e>li] times1 b ^! are accompani$ by %ells :i* are /raight1 curv$1 boat-%ap$1 & coil$ into v>i\s helicoid spirals1 sometimes hav+ ! :orls 9 contact1 :ile at o!r times !y are sep>ate4 ,9 ! *alk ( ,brita9 ga/ropods are on ! :ole r>e1 & ?is fact s]ves to emphasize ! palontological break :i* occurs betwe5 ! ,cretace\s & ,t]ti>y rocks2 b :5 conditions 7 fav\rable1 z dur+ ! deposition ( "s ( ! /rata ( ! ,middle ,*alk1 ga/ropods are abundant1 & "s are relat$ to ,t]ti>y g5]a1 s t we may assume t ! palontological break allud$ to is exagg]at$ by ! diff]5ce ( conditions :i* prevail$ dur+ ! deposition ( ! e>lie/ ,t]ti>y & late/ ,cretace\s s$im5ts4 ,9 ! ,cretace\s deposits ( ! s\!rn sea1 :]e ! ,ammonite tribe is almo/ unkn[n1 ! rem>kable family ( ! lamellibran*s kn[n z ! ,hippuritid furni% ! dom9ant inv]tebrates ( ! p]iod1 & ! repres5tatives ( ?is family are exce$+ly sc>ce among/ ! ,cretace\s /rata ( ! nor!rn gulf1 ?\gh !y are f\nd on two or ?ree horizons4 ,( v]tebrates1 ! mo/ int]e/+ are ! reptiles4 ,! families :i* pr$om9ate 9 ,jurassic times h _m repres5tatives among/ ! ,cretace\s /rata also1 b ! ord] ,squamata is repres5t$ by ! sub-ord] ,py?onomorpha1 :i* is *>act]i/ic ( ! ,cretace\s rocks4 ,! be/ kn[n repres5tative is ! gigantic ,mosasaurus4 ,la/ly1 we h ! rem>kable too!d birds or ,odontorni!s1 n[ plac$ 9 diff]5t ord]s1 ! g5us ,hesp]ornis be+ ! only repres5tative ( ! sub-ord] ,odontolc ( ! ,ratit1 :il/ ,i*?yornis & alli$ =ms are plac$ 9 ! sub-ord] ,odontorm ( ! ,c>9at4 ,,*apt] ,,xxiv4 ,,! ,,eoc5e ,,rocks4 ,classification4 ,! ,eoc5e ,b$s ( ! s\? ( ,engl& h be5 subdivid$ accord+ to ! v>iations 9 _! li?ological *>act]s1 & ! subdivisions h receiv$ local names4 ,! foll[+ classification is g5]ally adopt$1 ?\gh ! diff]5t subdivisions are by no means ( equal value3 ,upp] ,eoc5e ,upp] ,bag%ot ,b$s ,b>ton ,b$s ,middle ,eoc5e ,brackle%am ,b$s ,l[] ,bag%ot ,b$s ,london ,clay#ajc ,l[] ,eoc5e ,oldhav5 ,b$s ,l[] ,london ,woolwi* & ,read+ ,b$s ,t]ti>y ,/rata ,?anet ,s&s ,footnote #ajc3 ,"s writ]s place ! ,london ,clay 9 ! ,middle ,eoc5e4 ,! deposits v>y greatly :5 trac$ abroad1 & ! exact equival5ts ( ! m9or subdivisions ( ! ,briti% rocks c seldom be asc]ta9$ at any di/ance f ,engl&1 ?\gh ! division into ,upp]1 ,middle1 & ,l[] ,eoc5e c be made ov] wide areas4 ,description ( ! /rata4 ,! "* ( ! /rata ( ,europe & ,asia indicates ! p]si/5ce ( ! nor!rn gulf & s\!rn ocean ( ,cretace\s times 9 ,eoc5e times also1 ?\gh ! area ( ea* _h %runk 9 ! meantime1 ow+ to ! physiographical *anges :i* occurr$ at ! end ( ,cretace\s times1 giv+ rise to m ext5d$ l& areas1 & produc+ a %all[ wat] phase ov] wide ext5ts ( ocean1--! f9al %all[ wat] phase ( ! ?ird & la/ great m>9e p]iod ( ! ,briti% area4 ,x is difficult to asc]ta9 ! exact importance ( ! physical break betwe5 ,cretace\s & ,eoc5e rocks 9 ! s\?-ea/ ( ,engl&1 ow+ to ! subt]ranean solution ( ! upp] "p ( ! *alk1 subsequ5tly to ! deposition ( ! ,eoc5e /rata1 b ! contraction ( ! ,cretace\s gulf is %[n 9 sev]al ways1 "o ( ! mo/ significant be+ ! di/ribution ( ,cretace\s & ,eoc5e rocks 9 ! s\?-we/ ( ,engl&4 ,! exi/5ce ( an outli] ( ,cretace\s rock at ,buckl& ,brew] 9 ,nor? ,devon1 only ?ree miles f ! ,atlantic ,ocean1 indicates ! =m] ext5sion we/w>d ( ! ,upp] ,cretace\s b$s1 :ile ! occurr5ce ( an outli] ( ,eoc5e rocks at ,bovey ,tracey 9 ,s\? ,devon1 re/+ n on ,cretace\s b on ,palozoic rocks1 %[s t !re 0 an uplift aft] ! deposition ( ! ,cretace\s rocks & be=e ! ,eoc5e rocks 7 deposit$ !re1 & t dur+ ! p]iod ( uplift ! ,cretace\s rocks 7 remov$4 ,ow+ to ^! physical *anges1 ! ,eoc5e rocks ( ,brita9 are ma9ly me*anical s$im5ts1 "s1 z ! ,oldhav5 b$s1 be+ compos$ ( co>se pebbles ov] a fairly wide di/rict1 :ile "s ( ! e>li] ,eoc5e rocks are e/u>9e or fluvio-m>9e4 ,! ,eoc5e rocks ( ,brita9 occur 9 f\r areas1 namely1 ! ,london ,bas91 ! ,hamp%ire ,bas91 ! ,bovey ,tracey outli]1 & ! nor?-ea/ ( ,irel& & we/]n ,isles ( ,scotl&4 ,! deposits ( ! ?ree s\!rn areas may be consid]$ toge!r1 & give g5]al indications ( an approa* to l& :5 pass+ we/w>d4 ,! ,l[] ,london ,t]ti>y /rata are fluvio-m>9e at ! ea/ end ( ! ,london ,bas92 !y become %all[] wat] deposits :5 trac$ we/w>d1 & beg9 to disappe>4 ,! ,london ,clay is an e/u>9e deposit1 :i* is g5]ally suppos$ to h be5 laid d[n at ! m\? ( a l>ge riv] fl[+ f ! we/4 ,x is abs5t 9 ! ,bovey ,tracey outli]4 ,local di/urbances caus$ ! exi/5ce ( a %all[ wat] region 9 ! ea/ dur+ ! deposition ( ! ,middle & ,upp] ,eoc5e deposits1 & accord+ly ! well-m>k$ m>9e deposits :i* =m ! repres5tatives ( ^! divisions 9 ,hamp%ire are replac$ by ! ,bag%ot b$s ( ! ,london ,bas91 consi/+ *iefly ( co>se me*anical s$im5ts ) a poor m>9e fauna1 b ev5 9 ! we/ %all[ wat] prevail$ at times dur+ ! accumulation ( v>i\s plant-be>+ /rata4 ,! ,middle ,eoc5e b$s only are f\nd 9 ! ,bovey ,tracey outli]1 ?\gh ! ,upp] ,eoc5e b$s may orig9ally h be5 laid d[n 9 t area1 & subsequ5tly d5ud$4 ,! f\r? area displays a v diff]5t succession ( ,eoc5e /rata1 & "o ( extreme int]e/4 ,me*anical s$im5ts & plant-be>+ clays & lignites alt]nate ) a va/ accumulation ( basaltic lavas1 indicat+ ! outbreak ( ! volcanic =ces 9 ! ,briti% area1 aft] a p]iod ( quiesc5ce :i* la/$ ?r\gh ! great] "p ( ,mesozoic times4 ,! region 9 :i* ^! lavas 7 p\r$ out 0 probably a l& area dur+ ! great] "p ( ! p]iod ( volcanic activity1 b ! horizontal lie ( ! lava fl[s & _! wide ext5t indicate ! exi/5ce ( a flat tract ( c\ntry1 gradually rais$ into a plateau by ! accumulation ( %eet ov] %eet ( basalt4 ,h[ f> ?is plateau ext5d$ x is impossible to say4 ,! di/ribution ( ! lavas at ! pres5t day is some:at limit$ 9 our isles1 b !re is no sign ( dy+ out at ! pres5t m>g9s ( ! accumulations1 & !y h probably escap$ d5udation 9 ^! regions1 z ma9ta9$ by ,pr(essor ,judd1 on acc\nt ( ! faults :i* h depress$ !m1 :ile ! portions :i* 7 n depress$ h be5 remov$ by d5udation4 ,two views z to ! orig9 ( ! lavas h be5 put =w>d3 accord+ to ,pr(4 ,judd1 !y 7 p\r$ =? f gigantic volcanoes1 :ile ,sir ,a4 ,geikie ma9ta9s t !y repres5t portions ( massive or fissure eruptions1 ! molt5 rock hav+ well$ out f great cracks 9 ! e>?1 :i* are n[ fill$ by once molt5 rock 9 ! =m ( dykes4 ,z ^! dykes ext5d f> away f ! pres5t volcanic plateau1 "o actually ext5d+ to ! ,york%ire coa/1 we may well believe1 :atev] 0 ! orig9 ( ! %eets ( lava1 t !y 7 =m]ly spread f> away f _! pres5t t]m9ations#ajd4 ,)\t ent]+ "h into a discussion ( ! exact nature ( extrusion ( ^! igne\s %eets1 x w suffice to say t all ! evid5ce po9ts to ! =mation ( ext5sive plateaux1 :i* mu/ h pres5t$ a fairly uni=m surface1 simil> to t :i* is /ill f\nd *>act]is+ ! volcanic di/ricts ( ! we/]n t]ritories ( ,nor? ,am]ica4 ,footnote #ajd3 ,pr(4 ,judd's views w be f\nd 9 a s]ies ( pap]s by him on ! ,second>y ,rocks ( ,scotl&1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxix4 p4 #ie1 ,,xxx4 p4 #bbj1 ,,xxxiv4 p4 #ffj1 :ile ,sir ,a4 ,geikie's explanation is advanc$ 9 a pap] 9 ! ,transactions ( ! ,royal ,society ( ,ed9burgh1 vol4 ,,xxxv42 see also ! same au?or's ,anci5t ,volcanoes ( ,great ,brita94 ,! ,eoc5e rocks ( ! nor?-we/ ( ,europe possess *>act]s v simil> to ^? ( ! s\? ( ,engl&1 & !re are indications t ! nor!rn gulf _h dim9i%$ 9 ext5t t[>ds ! ea/ z well z t[>ds ! we/4 ,pass+ to s\!rn ,europe1 ,c5tral ,asia & nor!rn ,africa1 we f9d ! conditions ( ,cretace\s times reproduc$1 & an ext5sive s]ies ( m>9e deposits ext5ds v widely ov] ^! regions1 ! mo/ p]si/5t deposit be+ a mass ( lime/one ( ,middle ,eoc5e age1 :i* is almo/ entirely compos$ ( ! te/s ( ,nummulites1 :5ce ! developm5t is kn[n z ! ,nummulitic ,lime/one facies1 & we may speak ( ! ocean z ! ,nummulitic ,lime/one ,sea4 ,! incom+ ( %all[ wat] conditions m>k$ by accumulation ( co>se me*anical s$im5ts t[>ds ! end ( ! ,eoc5e p]iod 9 "s p>ts ( ! s\!rn ,european area indicates ! sett+ 91 ev5 !n1 ( ^? cont95tal conditions :i* culm9at$ dur+ ! ,mioc5e p]iod4 ,9 ,nor? ,am]ica we get simil> evid5ce ( ! contractions ( ! oceans :i* 9 ,mesozoic times occupi$ l>ge expanses ( our pres5t cont95ts4 ,! climatic conditions ( ,eoc5e times h be5 notic$ 9 pass+ 9 *apt] ,,ix41 & evid5ce 0 giv5 to prove ! preval5ce ( a w>m] climate ov] ! ,briti% area ?an t :i* n[ exi/s4 ,a /udy ( ! floras ( v>i\s p>ts ( ! nor!rn hemisph]e sugge/s t climatic zones1 ^: l9es ( dem>cation ran practically p>allel ) ! ,equator1 exi/$ 9 ,eoc5e times also1 ?\gh fur!r in=mation ^u ?is subject is desirable4 ,! ,eoc5e flora & fauna4 ,! flora ( preval5t dicotyl$on\s angiosp]ms1 :i* appe>$ 9 ,upp] ,cretace\s times1 also m>ks ! ,eoc5e & lat] deposits1 b a /udy ( ! floras indicates t ! diff]5tiation :i* n[ m>ks (f ! floras ( diff]5t areas f "o ano!r _h n occurr$ to s great an ext5t z at ! pres5t "t4 ,! exi/5ce ( a ri* flora 9 ! ,eoc5e b$s ( circumpol> regions 9 ! nor!rn hemisph]e %\ld be not$1 ?\gh p]haps its importance has be5 some:at exagg]at$4 ,! inv]tebrate fauna %[s an approximation to t ( ! pres5t day4 ,! rem>kable ammonite fauna ( ,mesozoic times has disappe>$1 & ga/ropods & lamellibran*s pr$om9ate1 _m ( ! =ms belong+ to exi/+ g5]a1 ?\gh v r>ely to exi/+ species4 ,! ,nummulites are ! mo/ *>act]i/ic ,eoc5e fossils1 & ! p]iod may be spok5 ( z ! ,nummulitic ,p]iod1 ?\gh x is n[ kn[n t ,nummulites are n conf9$ to ! ,eoc5e /rata4 ,! v]tebrate fauna is v notewor?y4 ,! fi%es & reptiles are closely relat$ to exi/+ =ms1 & ! ord]s ( reptiles :i* pr$om9at$ 9 ,mesozoic times h completely disappe>$4 ,b ! mammals are ! mo/ int]e/+ v]tebrates ( ! ,eoc5e p]iod4 ,in/ead ( ! l[ly organis$ =ms ( ,mesozoic times1 we f9d repres5tatives ( _m ord]s1 includ+ ! highe/1 ! ,primates4 ,! g5]alis$ =ms :i* s]ve z l9ks betwe5 gr\ps :i* are n[ sep>at$ to a consid]able ext5t are ( p>ticul> importance4 ,!y h be5 detect$ 9 ,eoc5e rocks ( v>i\s regions1 ?\gh ! mo/ complete s]ies h be5 obta9$ f ! ,eoc5e rocks ( ,nor? ,am]ica & made kn[n to u ?r\gh ! num]\s memoirs ( ,pr(essors ,cope & ,m>%#aje4 ,footnote #aje3 ,! ,eoc5e floras ( ,brita9 are describ$ by ,mr ,j4 ,/>kie ,g>dn] & ,b>on von ,ett+%aus5 9 ! ,monographs ( ! ,palontographical ,society2 o!r ,monographs ( ! same ,society conta9 an acc\nt ( ! ,eoc5e ,mollusca by ,mr ,f4 ,e4 ,edw>ds & ,mr ,s4 ,v4 ,wood4 ,an idea ( ! g5]alis$ =ms ( ,mammalia may be obta9$ by p]usal ( t portion ( ,ni*olson & ,lydekk]'s ,manual ( ,palontology 9 :i* ! latt] au?or treats ( ! ,mammalia1 & 9 ?is connexion ! read] w d well to read ,pr(4 ,huxley's ,lecture on ,fossil ,horses1 repr9t$ 9 8 ,am]ican ,addresses4 ,,*apt] ,,xxv4 ,,! ,,oligoc5e ,,& ,,mioc5e ,,p]iods4 7i7 ,! ,oligoc5e ,b$s4 ,classification4 ,! ,oligoc5e ,b$s ( ,brita9 are classifi$ z foll[s3-- ,upp] ,want+ ,middle ,hemp/ead ,b$s ,bembridge ,b$s ,l[] ,osborne ,b$s ,headon ,b$s ,description ( ! /rata4 ,little ne$ be said ( ! deposits ( ?is p]iod1 ei!r 9 ,brita9 or abroad1 except to rem>k t !y %[ ! fur!r spread ( cont95tal conditions ov] ! regions n[ occupi$ by l&4 ,! ,briti% deposits are n[ se5 9 ! ,hamp%ire ,bas9 only1 & h be5 spok5 ( z ! fluvio-m>9e s]ies1 z _m ( ! /rata 7 laid d[n 9 cont95tal %eets ( wat]1 :ile ! true m>9e s$im5ts are ?9 & infrequ5t4 ,! li?ological *>act]s ( deposits =m$ "u ^! conditions naturally v>y greatly1 consi/+ ( diff]5t k9ds ( me*anical s$im5ts occasionally mix$ ) ?9 fre%wat] m>ls & lime/ones4 ,on ! ,cont95t simil> conditions prevail$1 ?\gh ! occurr5ce ( fairly wide tracts ( level surface is indicat$ by ! widespread di/ribution ( b$s ( br[n coal or lignite1 & ! co>se & ?ick ,oligoc5e 'nagelfluh' ( ,switz]l& po9ts to ! elevation ( m\nta9 ranges 9 ! neighb\rhood4 ,! flora & fauna4 ,! rem>ks made conc]n+ ! ,eoc5e flora & fauna are g5]ally applicable to ^? ( ,oligoc5e times1 except t ! ,oligoc5e fossils be> a /ill clos] resemblance to liv+ =ms1 & ! ,nummulites are no long] dom9ant4 7ii7 ,! ,mioc5e ,p]iod4 ,b$s ( ,mioc5e age are want+ 9 ,brita91 & on ! ,cont95t !y occur 9 isolat$ bas9s deposit$ 9 gulf-l prolongations ( ! ocean1 nev] v f> f l&4 ,a description ( ! /rata & _! fossil cont5ts w\ld be ( little use = our pres5t purposes1 & ! rem>ks made conc]n+ ! ,oligoc5e b$s w apply to ! ,mioc5e /rata also4 ,! p]iod 0 ma9ly rem>kable on acc\nt ( ! important physical *anges :i* occurr$1 to :i* we mu/ devote "s consid]ation4 ,comm5c+ ) ! ,briti% area1 we f9d 9 ! s\? evid5ce ( ! sep>ation ( ! ,london & ,hamp%ire ,bas9s at ?is "t1 = ! ,oligoc5e b$s ( ,hamp%ire are tilt$ up on ! s\? side ( an anticl9e1 :i* sep>ates ! ,hamp%ire ,bas9 f t ( ,london1 indicat+ t ! movem5t 0 po/-,mioc5e1 :ile 9 ,k5t1 b$s ( ,plioc5e age re/ on ! d5ud$ top ( ! *alk1 %[+ t ! elevation & d5udation :i* accompani$ x 7 pre-,plioc5e2 ! great ,weald5 anticl9e is ?us se5 to be ( ,mioc5e age4 ,on ! nor? side ( ! ,london ,bas9 ! l9e ( dem>cation betwe5 ,eoc5e & ,mesozoic b$s runs approximately p>allel to ! /rike ( ! latt] 9 t "p ( ,brita91 & ?is po9ts to ! elevation ( ! ,mesozoic /rata :i* gave !m _! pres5t s\?-ea/]ly dip ab\t ! same p]iod1 ?\gh 9 ! abs5ce ( ,oligoc5e rocks x _c be def9itely /at$ t ! movem5t 0 altoge!r po/-,oligoc5e4 ,! pres5t physical geography ( consid]able p>ts ( ,brita9 mu/ date f ,mioc5e times4 ,important z ! *anges 7 9 ,brita91 !y 7 slight z comp>$ ) ^? :i* affect$ ,europe & _m p>ts ( ,asia4 ,! great m\nta9 *a9s ( ! ,old ,_w receiv$ _! maximum uplift dur+ ?is great p]iod ( e>?-movem5t1 & orog5ic /ructures 7 impress$ ^u ! rocks ( _m regions1 = ! ,t]ti>y ,m\nta9 ,*a9s ( ! ,old ,_w h an ,alp9e /ructure impress$ ^u !m z ! result ( int5se lat]al pressure1 accord+ly we f9d ! ,eoc5e /rata lift$ f> above _! orig9al level to heights ( #h1jjj feet 9 ! ,alps & ov] #ab1jjj feet 9 ! ,himalayas4 ,away f ^! m>k$ uplifts epeirog5ic movem5ts caus$ ! disappe>ance ( ! seas ( e>li] ,eoc5e times1 s t t[>ds ! close ( ! ,mioc5e ,p]iod1 ! ma9 features ( ! ,eurasian cont95t 7 mu* z !y are n[4 ,! pres5t dra9age-sy/ems mu/ h orig9at$ at ! same "t1 & ! sculpture ( our cont95t has be5 c>ri$ on m or less cont9u\sly by suba]ial ag5ts f ,mioc5e times to ! pres5t day4 ,t any addition to ! total area ( l& 0 made is d\btful4 ,! l& :i* appe>s to h exi/$ to ! we/ ( ,brita9 dur+ ,cretace\s & ,eoc5e times f9ally disappe>$ b5ea? ! wat]s ( ! ,atlantic ,ocean1 & ! movem5t probably gave rise to ! prom95t subm>9e feature :i* n[ exi/s at "s di/ance f ! coa/ ( ,irel&4 ,a great m>9e p]iod is n[ exi/5t 9 our ocean areas1 b s f> z ! exi/+ cont95ts are conc]n$1 we are liv+ on ! f\r? cont95tal p]iod :i* practically came into exi/5ce 9 ,mioc5e times4 ,! /rike ( ! uplift$ /rata naturally co9cides on ! :ole ) ! axes ( ! major uplifts1 & accord+ly we f9d ! ,mesozoic & e>ly ,t]ti>y /rata fold$ ar\nd axes :i* h a preval5t ea/ & we/ direction1 ) o!rs :i* h a tr5d at "r angles to ?is4 ,! /rike ( ! ,briti% ,mesozoic rocks seems to h be5 det]m9$ by ea* ( ^! sets ( movem5ts1 s t al?\gh x is ea/ & we/ 9 ! s\? ( ,engl&1 x runs nor? & s\? 9 ! ea/]n c\nties nor? ( ! ,?ames4 ,9 ,am]ica1 al?\gh epeirog5ic movem5ts _h occurr$ be=e ,mioc5e times1 ) ! =mation ( wide cont95tal tracts1 ^! appe> to h be5 ( ! nature ( pla9s1 div]sifi$ by ext5sive inl& %eets ( wat]1 & uplift ( orog5ic "* conv]t$ ^! pla9s into unev5 tracts 9 ,mioc5e times4 ,_m ( ! movem5ts 9 ,am]ica1 :i* l ^? ( ,europe are /ill progress+ ) enfeebl$ p[]1 diff] f ^? ( ,eurasia1 giv+ rise to rais$ monocl9al blocks r ?an to viol5t folds ( ,alp9e "*1 z se5 9 ! we/]n t]ritories ( ,nor? ,am]ica1 & z prov$ also by ! diff]5tial movem5ts :i* are n[ kn[n to affect ! ,atlantic coa/ ( t cont95t4 ,accompany+ ^! *anges 9 ! e>?'s cru/ 7 o!rs :i* affect$ ! climate1 at any rate locally4 ,! w>m climate ( ,eoc5e times gradually gave way to a cool] climate 9 ,oligoc5e times1 & ?is l[]+ ( temp]ature 0 /ill fur!r advanc$ 9 ,mioc5e times1 ?\gh !re is evid5ce t ! temp]ature ( ^? p>ts ( ,europe :i* h /rata repres5tative ( ! ,mioc5e p]iod 0 high] ?an x is at ! pres5t day4 ,ow+ to ! *anges :i* occurr$ 9 ,mioc5e times1 ! area ( s$im5tation 0 ext5sively %ift$ to our pres5t oceans1 & accord+ly we f9d t ! times subsequ5t to ^? ( ! ,mioc5e uplifts are m>k$ by scatt]$ accumulations ( cont95tal "*1 ) a few insignificant m>9e /rata seldom f\nd f> inl& f ! pres5t coa/-l9es4 ,,*apt] ,,xxvi4 ,,! ,,plioc5e ,,b$s4 ,classification4 ,! ,italian ,plioc5e ,b$s :i* h long be5 kn[n h be5 divid$ into ?ree /ages1 to :i* names h be5 appli$ :i* are some:at widely us$1 ?\gh ! division ( ! ,briti% deposits into ! same ?ree /ages has n be5 made4 ,! /ages are3-- ,a/ian4 ,plaisancean4 ,zanclean4 ,! classification ( ! ,briti% deposits may be made z foll[s3-- ,crom] ,=e/ ,s]ies4 ,weyb\rne ,crag & ,bure ,valley ,b$s4 ,*illes=d ,crag4 ,norwi* ,crag & ,r$ ,crag4 ,upp] ,corall9e ,crag4 ,l[] ,corall9e ,crag4 ,z ! ,engli% deposits are some:at scatt]$ x is difficult to make out ! exact ord] ( succession1 b ! above %[s ! classification :i* is adopt$ by ! be/ au?orities1 ! ,norwi* ,crag 7or ,fluvio-m>9e ,crag z x is sometimes t]m$7 be+ n[ suppos$ to repres5t ! upp] portion ( ! ,r$ ,crag4 ,description ( ! /rata4 ,! ,briti% deposits are *iefly f\nd 9 ! c\nties ( ,norfolk & ,suffolk1 b isolat$ pat*es h be5 detect$ 9 ,k5t & at ,/ ,er? 9 ,cornwall2 :ile ! inclusion ( ,plioc5e fossils 9 ! glacial deposits ( ,ab]de5%ire & on ! we/ coa/s & isl&s ( ,great ,brita9 sugge/s ! occurr5ce ( ,plioc5e b$s b5ea? sea-level1 ar\nd ! ,briti% coa/s1 at no great di/ance f ! l&4 ,! t]m ',crag' has be5 appli$ to %elly s&s ( :i* ! ,briti% ,plioc5e b$s are l>gely compos$4 ,! olde/ ,briti% ,plioc5e /rata are suppos$ to be ! ,l5ham ,b$s1 occurr+ 9 'pipes' on ! ,*alk ( ! ,nor? ,d[ns1 :i* are ref]r$ to ! ,l[] ,corall9e ,crag1 & "s writ]s believe t ! ,/ ,er? b$s ( ,cornwall are ( simil> age#ajf4 ,! =m] are f]rug9\s s&s1 & ! latt] %elly s&s & clays4 ,! high] b$s ( ! ,corall9e ,crag are f\nd 9 ,suffolk1 & are l>gely calc>e\s1 be+ made ( rema9s ( polyzoa1 molluscs1 & o!r inv]tebrates4 ,!y 7 probably deposit$ 9 deep] wat] ?an ! re/ ( ! ,briti% ,plioc5e /rata1 & conta9 a f> l>g] p]c5tage ( c>bonate ( lime4 ,! ,r$ ,crag consi/s ( f]rug9\s %elly s&s1 ( ! nature ( s&-banks1 =m$ ne> l&2 :ile ! ,norwi* ,crag is ( a /ill m littoral "*1 & conta9s rema9s ( l& %ells & ! bones ( mammalia m+l$ ) ! m>9e %ells ( ! coa/4 ,! high] ,plioc5e deposits are also coa/al accumulations1 ev5 ! s-call$ ,=e/ b$ be+ a deposit & n a true surface soil1 z prov$ by ! obs]vations ( ,mr ,clem5t ,reid4 ,at ! summit ( ! ,crom] ',=e/' ,s]ies1 h[ev]1 is a true fre%wat] b$4 ,^! ,briti% deposits appe> to h be5 laid d[n on a coa/ l9e :i* =m$ "o side ( ! e/u>y ( a l>ge riv]1 ( :i* ! pres5t ,rh9e is ! 'betrunk$' portion 7to use a t]m introduc$ by ,pr(4 ,w4 ,m4 ,davis7#ajg4 ,footnote #ajf3 ,see ,clem5t ,reid1 ,nature1 #ahhf1 p4 #cdb2 & ,k5dall & ,bell1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlii4 p4 #bja4 ,footnote #ajg3 ,see a pap] by ,mr ,f4 ,w4 ,h>m]1 ,on ! ,plioc5e ,deposits ( ,holl&1 & _! relation%ip to ! ,engli% & ,belgian ,crags1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,lii4 p4 #gdh4 ,on ! ,european cont95t1 m>9e ,plioc5e b$s are f\nd 9 ,belgium & ,italy4 ,! =m] deposits greatly resemble our ,crags1 :il/ ! latt] are ( int]e/ on acc\nt ( ! mixture ( volcanic b$s ) m>9e s$im5ts 9 ,sicily1 %[+ t ! =mation ( ,etna comm5c$ 9 ,plioc5e times4 ,v>i\s deposits =m$ 9 inl& bas9s are f\nd 9 ,france & ,g]many1 b ! mo/ rem>kable occur 9 ! ,vi5na bas91 :]e ,caspian conditions prevail$ ov] l>ge areas1 & ! ord9>y /rata alt]nate ) *emical deposits ( :i* ! be/-kn[n are ! celebrat$ rock salt masses ( ,wieliczka1 ne> ,crac[4 ,at ! same "t volcanic activity 0 rife to ! s\? ( ! ,c>pa?ian m\nta9s4 ,o!r deposits1 :i* are p>tly ref]able to ! ,plioc5e p]iod1 occur 9 ,greece at ,pik]mi1 & 9 ,india 9 ! ,siwalik hills2 ^! are celebrat$ = _! rem>kable mammals1 z are ! ,plioc5e /rata ( ! ,we/]n t]ritories ( ,nor? ,am]ica4 ,! occurr5ce ( m>k$ e>?-movem5ts s9ce ,plioc5e times is indicat$ by ! nature ( ! deposits ( ,b>badoes1 :]e radiol>ian *]ts h furni%$ two e*9ids :i* are describ$ by ,dr ,gregory z deep-sea =ms4 ,^! b$s 7 once ref]r$ to ! ,mioc5e p]iod1 b !re is good reason = assign+ !m to a lat] date1 & correlat+ !m ) ! ,plioc5e b$s ( o!r areas1 9 :i* case !re mu/ h be5 a consid]able uplift 9 ?is region s9ce ,plioc5e times1 a fact ( great !oretical importance4 ,! climatic conditions ( ,plioc5e times %[ /eady fall ( temp]ature4 ,! e>ly ,plioc5e b$s ( ,brita9 7 deposit$ dur+ ! preval5ce ( w>m] temp]atures ?an ^? :i* n[ exi/ 9 ! same area1 b dur+ lat] ,plioc5e times1 ! temp]ature 0 at fir/ simil> to t n[ prevail+1 & aft]w>ds di/9ctly cold]1 & we f9d 9 ! upp] ,plioc5e b$s ! rema9s ( organisms ( a nor!rn type4 ,9 ! upp]mo/ deposit ( ! ,crom] ',=e/' ,s]ies1 ! arctic bir* & arctic will[ indicate ! comm5cem5t ( ! cold :i* culm9at$ 9 ! succe$+ ',great ,ice ,age4' ,! flora & fauna4 ,little ne$ be said ( ! ,plioc5e fossils3 ! flora approa*es t ( pres5t times1 & ! inv]tebrates are 9 mo/ cases specifically id5tical ) ^? n[ liv+4 ,! v]tebrates alone diff] m>k$ly f liv+ =ms1 be+ *iefly ( ext9ct species1 & 9 _m cases belong+ to ext9ct g5]a4 ,x is int]e/+ to f9d t ! mammalian fauna ( ,plioc5e times resembles ! exi/+ fauna ( ! area 9 :i* ! b$s are f\nd1 a fact long ago obs]v$ by ,d>w94 ,?us ! ,european ,plioc5e mammals are l exi/+ ,european =ms1 :il/ 9 ,au/ralia ! mammalian t]re/rial fauna consi/s ( ,m>supials1 & 9 ,s\? ,am]ica !re are ,ed5tata ( ,plioc5e age#ajh4 ,footnote #ajh3 ,! ,plioc5e fauna ( ,brita9 is describ$ by ,mr ,se>les ,v4 ,wood 9 ! ,monographs ( ! ,palontographical ,society4 ,,*apt] ,,xxvii4 ,,! ,,plei/oc5e ,,accumulations4 ,classification4 ,! t]m ,plei/oc5e1 z us$ "h1 is approximately equival5t to ! expressions ',glacial ,p]iod' & ',great ,ice ,age' ( "s writ]s2 b ,i h adopt$ x 9 pref]5ce to ^! expressions1 because x may ev5tually be possible to def9e ! ,plei/oc5e p]iod 9 su* a mann] z to give ! t]m a /rictly *ronological mean+1 :]eas ! o!r t]ms indicate ! exi/5ce ( climatic conditions :i* mu/ h ceas$ 9 "s areas soon] ?an 9 o!rs4 ,at pres5t1 climatic *ange gives u ! be/ means = sep>at+ ! accumulations =m$ subsequ5tly to ! ,plioc5e p]iod ov] l>ge p>ts ( ! ,eurasian l&-tract1 & ! mo/ conv5i5t division ( ^! cont95tal accumulations is to ref] !m to ?ree p]iods1 viz43-- ,! ,=e/ ,p]iod 79 :i* we are n[ liv+74 ,! ,/eppe ,p]iod4 ,! ,glacial ,p]iod4 ,"s ( ! accumulations :i* 7 =m$ dur+ ! ,/eppe p]iod are includ$ 9 ! ,plei/oc5e p]iod by _m writ]s1 b ,i pref] to treat ( !m z po/-,plei/oc5e4 ,9 ! pres5t /ate ( our k ( ! glacial deposits any attempt to make a classification applicable ov] v wide areas is doom$ to failure1 & ! v pr9ciples ^u :i* ! classification %\ld be bas$ are a subject ( disagreem5t4 ,! mo/ promis+ basis = classification is f\nd$ on alt]nate recession & advance ( l&-ice1 ?\gh ! pro(s t advance takes place simultane\sly ov] v wide areas are n yet =?com+4 ,dr ,j4 ,geikie 9 ! la/ edition ( 8 "w ,! ,great ,ice ,age adopts f\r p]iods ( glaciation1 ) int]v5+ p]iods ( recession1 & ?is division accords ) ! obs]vations ( _m =eign geologi/s4 ,9 ord] to und]/& ! me?od ( classification ^u ?is basis1 a few words conc]n+ glacial deposits 9 g5]al w n be out ( place4 ,glacial accumulations may be divid$ into ?ree classes3--7i7 true glacial accumulations1 =m$ on1 91 & "u ! ice1 & left beh9d ^u its recession1 7ii7 m>9e glacial deposits1 laid d[n 9 ! sea1 :5 float+ ice is ext5sively f\nd on its surface1 & 7iii7 fluvio-glacial deposits1 laid d[n by /reams :i* come f ! ice4 ,! two =m] indicate glacial conditions1 :ile ! occurr5ce ( fluvio-glacial deposits ov]la9 by true glacial deposits indicates an advance ( l&-ice1 = ! fluvio-glacial deposits are accumulat$ 9 front ( ^? :i* are truly glacial4 ,accord+ly if we f9d alt]nations ( glacial & fluvio-glacial deposits on a l>ge scale1 we may fairly inf] ! alt]nation ( p]iods ( great glaciation ) o!rs :5 ! ice dim9i%$1 or 9 o!r words ( glacial & int]glacial p]iods4 ,!re is1 h[ev]1 9 _m cases great difficulty 9 di/+ui%+ glacial deposits f m>9e glacial ones1 :ile "s ( ! true glacial deposits =m$ 9 ! ice 7englacial deposits7 _c readily be di/+ui%$ f ^? ( fluvio-glacial orig94 ,fur!rmore1 z ! t]m9al mora9es ( l&-ice (t5 re/ ^u o!r true glacial deposits1 x is (t5 difficult to "k :e!r we are deal+ ) ! products ( "o or two glaciations ov] limit$ areas4 ,! te/ ( sup]position is (t5 applicable1 & "o is enabl$ to obta9 "s clue z to ! relative ord] ( ev5ts4 ,9 ,engl& at lea/ ?ree p]iods ( glaciation seem to be indicat$ by ! glacial deposits4 ,on ! ea/ coa/ ! ,crom] ,=e/ ,s]ies is succe$$ by ! ,crom] ,till1 & 9 ,york%ire ! ,basem5t ,clay occupies a simil> position ) reg>d to ! ov]ly+ glacial accumulations to t ( ! ,crom] ,till4 ,:e!r ^! deposits be m>9e or t]re/rial1 & ! evid5ce is n yet suffici5t to settle ?is "q to ! satisfaction ( all geologi/s1 !re is no d\bt t !y are glacial4 ,above !m1 9 ,ea/ ,anglia1 lies ! ,contort$ ,drift1 ! orig9 ( :i* is /ill a moot po9t1 & x is ov]la9 by ! great ,*alky ,b\ld] ,clay1 :i* ext5ds f> & wide ov] ,ea/ ,anglia1 ! ,midl& ,c\nties & into ,york%ire4 ,evid5ce has be5 adduc$ to connect ?is ) ! till or b\ld] clay :i* spreads ov] ! upl& di/ricts ( ! nor? ( ,engl& at ! foot ( ! ma9 hill-sy/ems4 ,?is set ( deposits indicates a second glaciation4 ,z ! upl& till is (t5 pl\gh$ out by glaci]s :i* h left _! traces 9 ! =m ( mora9es 9 our upl& regions1 we seem "h to h evid5ce ( a ?ird glaciation1 :i* naturally leaves no traces 9 ! s\!rn di/ricts1 & ! exact age ( ?is _c be asc]ta9$ 9 ! abs5ce ( fossil evid5ce1 ?\gh we may provisionally ref] x to ! ,plei/oc5e p]iod4 ,ano!r attempt has be5 made to classify ! glacial deposits1 on ! supposition t !re h be5 p]iods ( elevation & depression ( ! l& dur+ ,plei/oc5e times4 ,"s writ]s advocate "o int]glacial p]iod :5 ! l& 0 depress$ to an ext5t ( #adjj & p]haps #bjjj feet1 :ile o!rs h advocat$ ! occurr5ce ( a numb] ( su* int]glacial m>9e p]iods4 ,! evid5ce = ! suppos$ oscillations is furni%$ by ! exi/5ce ( %ell-be>+ s&s associat$ ) b\ld] clays at high levels1 ! be/ kn[n be+ on ,moel ,tryfan 9 ,ca]n>von%ire1 ne> ,macclesfield 9 ,*e%ire1 & ne> ,oswe/ry 9 ,%rop%ire4 ,z _m geologi/s believe t ^! %ells h be5 c>ri$ to _! pres5t position by ice 9 a way :i* x is n our prov9ce to discuss "h1 we may dismiss ?is me?od ( classification z bas$ ^u ev5ts :i* _c be prov$ to h occurr$4 ,9 ! pres5t /ate ( our k1 x is inde$ be/ to avoid1 z f> z possible1 classifications :i* are int5d$ to be applicable ov] wide regions1 & to devote our att5tion to local details1 gradually piec+ toge!r ! evid5ce :i* is obta9$ z ! result ( exhau/ive exam9ation ( ea* sep>ate area#aji4 ,footnote #aji3 ,! glacial lit]ature ( our own isl& only1 is s ext5sive t ! /ud5t may well be bewild]$ :5 he attempts to grapple ) x4 ,he is recomm5d$ to read ! foll[+ g5]al works3 ,j4 ,geikie1 ,! ,great ,ice ,age4 #crd ,edition1 #ahid4 ,h4 ,c>vill ,lewis1 ,! ,glacial ,geology ( ,great ,brita9 & ,irel&4 #ahid4 ,g4 ,f4 ,wright1 ,man & ! ,glacial ,p]iod1 #ahib1 & ,! ,ice ,age 9 ,nor? ,am]ica1 #ahij4 ,sir ,c4 ,lyell1 ,antiquity ( ,man4 #d? ,edition1 #ahgc4 ,= ! glacial geology ( special regions ! foll[+ pap]s may be consult$3 ,! ,lake ,di/rict & adjo9+ neighb\rhood4 ,e4 ,h4 ,tiddeman1 ,evid5ce = ! ,ice ,%eet 9 ,nor? ,lanca%ire c4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxviii4 p4 #dga4 ,j4 ,g4 ,good*ild1 ,glacial ,ph5om5a ( ! ,ed5 ,valley c4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxi4 p4 #ee1 & ,j4 ,c4 ,w>d1 ,mem4 ,geol4 ,survey1 ,! ,geology ( ! ,nor!rn half ( ! ,lake ,di/rict4 ,york%ire4 ,g4 ,w4 ,lamplugh1 ,drift ( ,flambor\gh ,head1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlvii4 p4 #chd4 ,l9coln%ire4 ,a4 ,j4 ,jukes-,br[ne1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xxxv4 p4 #cig & ,,xli4 p4 #aad4 ,ea/ ,anglia4 ,clem5t ,reid1 ,mem4 ,geol4 ,survey1 ,! ,geology ( ! di/rict ar\nd ,crom]4 ,nor? ,wales4 ,t4 ,mc,k4 ,hughes1 ,drifts ( ! ,yale ( ,clwyd c4 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xliii4 p4 #gc1 & ,a4 ,/rahan1 ,glaciation ( ,s\? ,lanca%ire1 ,*e%ire1 & ! ,wel% ,bord]1 ibid41 vol4 ,,xlii4 p4 #dhf4 ,switz]l&4 ,c4 ,s4 du ,ri*e ,prell]1 ,on ,fluvio-glacial & ,int]glacial ,deposits 9 ,switz]l&1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,li4 p4 #cfi & ,on ,glacial ,deposits1 ,preglacial ,valleys & ,int]glacial ,lake =mations 9 ,sub-,alp9e ,switz]l&1 ibid41 vol4 ,,lii4 p4 #eef4 ,! read] w f9d ref]5ces to o!r works on ! ,glacial ,geology ( o!r di/ricts by consult+ ! g5]al works ref]r$ to on ! prec$+ page4 ,! =ego+ rem>ks w conv9ce ! /ud5t t any attempt to %[ ! di/ribution ( l& & sea dur+ any "p ( ! glacial p]iod is n likely to meet ) g5]al acceptance1 z s mu* dep5ds ^u ! t]re/rial or m>9e orig9 ( ! deposits ( ! l[l&s1 & ! mode ( =mation ( ! %ell-be>+ drifts ( high levels4 ,! occurr5ce ( elevation to a great] height ?an t :i* our c\ntry at pres5t possesses dur+ portions at any rate ( ! glacial p]iod has be5 inf]r$ on g5]al gr\nds1 b direct evid5ce 9 fav\r ( x is furni%$ by ! exi/5ce ( a numb] ( anci5t valleys on ! l& ar\nd our coa/s1 ^: floors are (t5 consid]ably bel[ sea-level1 :ile ! valleys are n[ completely fill$ up ) glacial accumulations1 except :]e !y h be5 p>tially re-excavat$ by /reams :i* = "s di/ance run above ! c\rses ( ! anci5t /reams4 ,! climatic conditions ( glacial times c only be briefly t\*$ ^u 9 ?is place4 ,if ! p]iods ( advance c be prov$ to be contemporane\s ov] wide areas1 ?is po9ts to alt]nations ( cold] & w>m] p]iods1 or at any rate ( dri] & wett] p]iods1 ?\gh local advance may be due to a numb] ( causes4 ,x mu/ be borne 9 m9d t ) ! temp]ature rema9+ ! same1 advance ( ice c be br\ght ab\t by increas$ precipitation ( aque\s vap\r 9 ! =m ( sn[4 ,! "q ( ! cause ( ! glacial p]iod is "o t only indirectly affects ! /ratigraphical geologi/ until he has accumulat$ suffici5t evid5ce to indicate ! cause4 ,x mu/ suffice to obs]ve t ! extremely plausible hypo!sis ( ,croll 7= :i* ! /ud5t %\ld consult ,dr ,croll's ,climate & ,"t7 does n expla9 ! app>5t gradual l[]+ ( climate ?r\gh\t ,t]ti>y times till ! cold culm9at$ 9 ! ,plei/oc5e p]iod1 & ! /ud5t w d well to rema9 9 susp5se conc]n+ ! cause ( ! ,ice ,age until fur!r evid5ce has be5 br\ght to be> ^u x4 ,! glacial flora & fauna4 ,! glacial deposits naturally yield few traces ( life1 except ^? :i* h be5 d]iv$ f o!r deposits1 & we are dep5d5t = our in=mation conc]n+ ! fauna & flora ( ! glacial p]iod ^u ! rema9s furni%$ by ! int]glacial deposits4 ,un=tunately x is v h>d to asc]ta9 :i* deposits are int]glacial1 & _m :i* h be5 claim$ z su* are ei!r preglacial or po/glacial4 ,! meagre evid5ce :i* we possess po9ts to ! exi/5ce ( an arctic fauna or flora 9 ,brita9 dur+ ! preval5ce ( ?is glacial p]iod4 ,a "q :i* has receiv$ mu* att5tion ( rec5t ye>s is t ( ! exi/5ce ( preglacial or int]glacial man1 on :i* mu* has be5 writt54 ,! exi/5ce ( man 9 glacial times is probable1 b x is ! op9ion ( _m ( ^? :o are mo/ compet5t to =m a judgm5t1 t x has n be5 prov$ 9 ! only conclusive way1 namely1 by ! discov]y ( relics ( man 9 deposits :i* are directly ov]la9 by glacial deposits1 or :i* at any rate are demon/rably old] ?an glacial deposits#aaj4 ,footnote #aaj3 ,on ! "q ( preglacial & int]glacial man1 see ,w4 ,boyd ,dawk9s1 ,e>ly ,man 9 ,brita92 ,h4 ,hicks1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlii4 p4 #c1 ,,xliv4 p4 #efa1 & ,,xlviii4 p4 #dec2 ,t4 ,mc,k4 ,hughes1 ibid41 vol4 ,,xliii4 p4 #gc2 ,sir ,j4 ,evans1 ,presid5tial ,address to ,briti% ,assoc4 #ahig4 ,,*apt] ,,xxviii4 ,,! ,,/eppe ,,p]iod4 ,! occurr5ce ( a p]iod m>k$ by dry climate ov] wide areas ( ! ,eurasian cont95t1 & possibly also 9 ,nor? ,am]ica1 is evid5c$ by ! widespread di/ribution ( an accumulation kn[n z loess1 conc]n+ ! orig9 ( :i* !re has be5 mu* diff]5ce ( op9ion1 ?\gh t x 0 =m$ subsequ5tly to ! glacial p]iod seems to be g5]ally admitt$1 inasmu* z x is l>gely compos$ ( re>rang$ glacial mud4 ,! =mation ( ! loess z a /eppe-deposit 0 fir/ advocat$ by ,b>on von ,ri*?(51 & 8 views 7 support$ by ,nehr+ aft] /udy ( ! loess-fauna4 ,ri*?(5's explanation ( ! loess z due to ! spread ( du/ by w9d 9 a dry region is becom+ widely accept$1 & x necessitates ! widespread occurr5ce ( /eppe conditions1 z ! loess has a v ext5sive geographical range1 & may be truly reg>d$ z ! normal cont95tal deposit ( ,eurasia dur+ ! p]iod imm$iately succe$+ ! glacial p]iod4 ,9 our own c\ntry1 z ! sea _c h be5 f> di/ant dur+ ^! times ! normal loess is n f\nd1 b sev]al accumulations occur1 :i* on /ratigraphical & palontological gr\nds mu/ be reg>d$ z syn*ron\s ) ! =mation ( ! loess4 ,^! are c]ta9 rubble-drifts ( ! s\!rn c\nties1 ! old] riv]-gravels ( s\!rn ,engl&1 & "s ( ! old] cave deposits ( v>i\s p>ts ( ,engl&4 ,x is d\btful :e!r any classification into m9ute subdivisions c be adopt$ = !m1 ?\gh ,pr(4 ,boyd ,dawk9s has advocat$ _! sep>ation into an old] age ( ,riv] ,drift ,man1 & a new] p]iod ( ,cave ,man1 on acc\nt ( ! evid5ces ( a l[] /ate ( civilisation af=d$ by exam9ation ( ! ,riv] ,drift implem5ts :5 comp>$ ) ^? fa%ion$ by ,cave ,man4 ,r\ghly speak+1 ! ,/eppe p]iod corresponds ) ! p]iod dur+ :i* ,paloli?ic man exi/$1 at any rate 9 nor?-we/ ,europe1 & we may speak ( ! ,/eppe p]iod z ! ,paloli?ic p]iod1 )\t ass]t+ t ,paloli?ic man necess>ily disappe>$ at ! "t :5 ! climate *ang$ & caus$ ! replacem5t ( ,/eppe conditions by o!rs fav\rable to =e/-gr[?4 ,description ( ! accumulations4 ,! loess consi/s ( un/ratifi$ calc>e\s mud or du/1 ) a peculi> v]tical fracture1 & is int]e/+ r on acc\nt ( ! nature ( its fossils & ( its di/ribution ?an = its li?ological *>act]s4 ,z x is n f\nd 9 ,brita9 x is n necess>y to say mu* ab\t x1 b m]ely to ref] to ! publi%$ descriptions#aaa4 ,footnote #aaa3 ,an acc\nt ( ,ri*?(5's views by t au?or w be f\nd 9 ! ,geological ,magaz9e1 ,dec4 #b1 vol4 ,,ix4 7#ahhb71 p4 #bic1 & ! fauna ( ! loess is describ$ by ,nehr+ 7,ibid41 p4 #egj74 ,! ,briti% deposits require "s notice1 z _! *>act]s & mode ( occurr5ce are ( "s significance4 ,along ! s\? coa/ are deposits ( co>se rubble :i* h yield$ "s organic rema9s1 :i* h be5 describ$ by ,mr ,clem5t ,reid#aab1 :o also discusses _! orig94 ,! rock1 also kn[n z ! ,elephant ,b$1 consi/s ( angul> fragm5ts ( fl9t & *alk1 & seems to h be5 produc$ by /reams :i* 7 able to fl[ ov] ! surface ( ! *alk :5 x 0 froz54 ,_m o!r simil> deposits 9 ! s\? ( ,engl&1 :i* are f\nd on ! op5 surface1 may h _h a simil> orig94 ,footnote #aab3 ,c4 ,reid1 ,orig9 ( ,dry ,*alk ,valleys & ( ,coombe ,rock1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xliii4 p4 #cfd4 ,! ,paloli?ic riv]-gravels are f\nd at v>i\s di/ances above pres5t riv]-levels1 & are ! surviv+ relics ( alluvial deposits :i* 7 laid d[n :5 ! riv]s ran at a high] level ?an !y n[ d4 ,t !y are new] ?an ! ma9 glacial drifts ( ! region 9 :i* !y occur is indicat$ by ! frequ5t pres5ce 9 !m ( b\ld]s d]iv$ f ! drift4 ,_! antiquity is %[n by ! physical *anges :i* h occurr$ s9ce _! deposition 7!re hav+ be5 suffici5t "t s9ce !n to all[ ( ! excavation ( "s riv]-valleys to a dep? ( ov] "o hundr$ feet b5ea? _! =m] level71 & also by ! "* ( ! includ$ mammals :i* w pres5tly be ref]r$ to4 ,! deposits v>y 9 co>s5ess1 l ^? ( mod]n alluvial flats1 f ! co>se gravels ( ! riv]-b$s to ! f9e loams & m>ls ( ! flood-pla9s4 ,!y are f\nd1 9 ,brita91 ) _! typical mammalian rema9s1 s\?-ea/ ( a l9e drawn f ! m\? ( ! ,tees to ! ,bri/ol ,*annel4 ,! cave-deposits h a wid] di/ribution ?an ^? :i* h j be5 notic$1 be+ also f\nd to ! nor?-we/ ( ! above-m5tion$ l9e 9 ,york%ire1 & 9 ,nor? & ,s\? ,wales4 ,9 ! s\? ( ,engl& !y are f\nd z f> ea/ z ,igh?am 9 ,k5t1 & 9 a we/]ly direction to ,torquay & ,t5by4 ,! ,igh?am deposits occur 9 fissures & consi/ ( mat]ials :i* 7 app>5tly introduc$ f above by riv] action#aac4 ,! cave-deposits ( lime/one areas are sometimes f\nd 9 fissures1 b at o!r times 9 cav]ns ) a fairly horizontal floor1 on :i* ! v>i\s accumulations lie 9 ord] ( =mation4 ,! deposits v>y 9 "* & may be divid$ into ?ree gr\ps1 ?\gh accumulations ( int]m$iate "* are f\nd2 ! fir/ gr\p consi/s ( cave-e>?s & cave-breccias--=m$ by wea!r+ ( ! lime/one1 & ! ret5tion ( ! insoluble residue1 z a m or less f]rug9\s mud1 mix$ ) angul> fragm5ts ( lime/one1 & ) ! rema9s ( creatures :i* inhabit$ ! caves2 ! second gr\p consi/s ( true deposits laid d[n "u wat]1 z gravels1 s&s1 & lam9at$ clays2 :ile ! ?ird is compos$ ( lime/one deposit$ f solution 9 wat]1 9 ! =m ( /alagmite#aad4 ,footnote #aac3 ,! ,igh?am fissures & _! cont5ts are describ$ by ,messrs ,abbot & ,newton1 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,l4 pp4 #aga & #ahh4 ,footnote #aad3 ,! read] %\ld consult ,pr(4 ,w4 ,boyd ,dawk9s' works on ,cave ,hunt+ & ,e>ly ,man 9 ,brita91 = in=mation conc]n+ ! ,cave ,deposits4 ,see also ,sir ,c4 ,lyell1 ,antiquity ( ,man2 ,sir ,j4 ,evans1 ,anci5t ,/one ,implem5ts ( ,great ,brita91 & ,sir ,j4 ,lubbock1 ,prehi/oric ,times4 ,9 ^! works ref]5ces w be f\nd to pap]s by ,messrs ,p5gelly1 ,mag5s ,mello1 ,tiddeman & o!rs on ! ,caves ( ,devon1 ,d]by%ire & ,york%ire4 ,ref]5ces h already be5 made to pap]s ^u ! ,cav]ns ( ,nor? ,wales4 ,! organic cont5ts ( ! ,paloli?ic p]iod are ( mu* int]e/1 & x is desirable to discuss _! "* be=e mak+ fur!r obs]vations ^u ! physical conditions ( ! p]iod4 ,! ,paloli?ic flora & fauna4 ,! plants ( "s ( ! e>li] deposits ( ! age we are consid]+ %[ ! preval5ce ( cold conditions dur+ _! accumulation1 = in/ance ! ,arctic bir* & ,arctic will[ are f\nd 9 ! accumulations b5ea? ! implem5t-be>+ ,paloli?ic deposits ( ,hoxne 9 ,suffolk#aae4 ,! inv]tebrate fauna consi/s ess5tially ( ! rema9s ( molluscs4 ,! loess molluscs are *iefly pulmonif]\s ga/ropods :i* liv$ ^u ! l&1 ?\gh swamp =ms are occasionally associat$ ) !m4 ,! paloli?ic riv]-gravels h yield$ num]\s l&- & fre%wat]-molluscs ( liv+ species1 ?\gh "s :i* are abundant 9 ! ,briti% gravels are n[ ext9ct 9 ,brita91 e4g4 ,cyr5a 7,cobicula7 flum9alis & ,unio littoralis4 ,m>9e deposits ( ?is age are occasionally f\nd1 z at ,m>*1 9 ,cambridge%ire1 :]e ! fauna closely resembles t ( our pres5t sea-%ores4 ,footnote #aae3 ,^! b$s are describ$ by ,messrs ,reid & ,ridley1 ,geol4 ,mag4 ,dec4 ,,iii4 vol4 ,v4 p4 #dda4 ,see also ,c4 ,reid on ! ,hi/ory ( ! ,rec5t ,flora ( ,brita91 ,annals ( ,botany1 vol4 ,,ii4 ,no4 #h1 ,aug4 #ahhh4 ,! v]tebrate rema9s are mu* m rem>kable1 & x is n q cle> t ! association ( =ms ^: liv+ allies n[ live "u widely diff]5t conditions has be5 satisfactorily expla9$4 ,! riv]-gravels & cave-deposits conta9 rema9s ( temp]ate =ms1 z ! bison1 & br[n be>1 associat$ ) ^? ( nor!rn =ms1 z ! mammo?1 woolly rh9oc]os1 glutton1 re9de]1 & musk ox1 & also ) ^? ^: liv+ allies are inhabitants ( w>m] regions1 l ! lion1 hyna1 & hippopotamus4 ,"o ( ! mo/ rem>kable creatures is ! sabre-too!d lion or ,ma*airodus1 rema9s ( :i* h be5 discov]$ 9 ,k5t's ,cav]n1 ,torquay1 & 9 ! caves ( ,cresswell ,crags1 ,d]by%ire4 ,! loess fauna consi/s ( *>act]i/ic /eppe animals1 su* z ! j]boa1 ,saiga antelope & /eppe-porcup9e1 & x is int]e/+ to f9d an indication ( ?is fauna 9 ! ,igh?am fissures4 ,! fir/ und\bt$ relics ( mank9d are f\nd 9 ! ,paloli?ic deposits1 :i* are v widely spread ov] ! ,eurasian cont95t4 ,!y consi/ ma9ly ( implem5ts ( bone & /one1 ! latt] be+ *ipp$1 b nev] gr\nd or poli%$1 ?\gh bo? bone & /one implem5ts are frequ5tly ornam5t$ ) engrav$ figures4 ,! cave-deposits h furni%$ implem5ts ( a high] type ?an ^? usually f\nd 9 ! riv]-drifts1 b ! latt] are also f\nd 9 cav]ns 9 deposits b5ea? ^? conta9+ ! high] type1 h5ce ! division ( ! p]iod into two m9or p]iods1 t ( riv]-drift man1 & t ( cave-man#aaf4 ,footnote #aaf3 ,conc]n+ ?is matt]1 ! read] %\ld consult ,pr(4 ,boyd ,dawk9s' ,e>ly ,man 9 ,brita94 ,sir ,j4 ,pre/wi* has argu$ 9 fav\r ( ! exi/5ce ( a gr\p ( implem5ts f\nd on ! plateau s\? ( ! ,?ames ( an age antec$5t to t ( ! ord9>y riv]-drift implem5ts4 ,see ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlv4 p4 #bgj4 ,!re are sev]al que/ions ( int]e/ connect$ ) ! ,paloli?ic fauna1 ?ree ( :i* des]ve "s notice "h4 ,! abs5ce ( ! relics ( ! ,paloli?ic mammalia & ( ! human implem5ts 9 ! riv]-gravels nor?-we/ ( ! l9e drawn betwe5 ! ,tees & ,bri/ol ,*annel1 & ! pres5ce ( ! mammalian rema9s 9 ! cav]ns ( t area requires "s explanation4 ,"o su* explanation assumes t ! relics 7 de/roy$ 9 ! op5 c\ntry to ! nor?-we/ ( t l9e1 ow+ to glaciation1 b x is n by any means univ]sally accept$4 ,ano!r difficulty :i* 9 ! op9ion ( "s writ]s has n be5 fully cle>$ up is ! mixture ( app>5tly s\!rn =ms l ! ,hippopotamus1 ) o!rs ( nor!rn "* l ! ,musk ox1 "u su* conditions z to %[ t ! creatures liv$ 9 ! ,briti% area contemporane\sly4 ,seasonal migration might acc\nt = x1 b ! wide belt ( ov]lap ( app>5t nor!rn & s\!rn =ms requires some?+ m1 ?\gh secul> *anges ( climate might %ift ! belt ( seasonal ov]lap f "o place to ano!r1 caus+ ! entire belt ( ov]lap to ext5d ov] a consid]able di/ance4 ,! ?ird1 & p]haps mo/ important difficulty is ! abrupt *ange f ! ,paloli?ic type ( implem5t to ! ,neoli?ic type1 *>act]i/ic ( ! next p]iod4 ,"s implem5ts1 z ^? ( ! kit*5-midd5s ( ,d5m>k1 & ^? f\nd at ,br&on & ,cissbury 9 ?is c\ntry1 h be5 appeal$ to z int]m$iate 9 "*1 b evid5ce has be5 br\ght =w>d to %[ t ea* set is truly ,neoli?ic1 ! "o be+ ! implem5ts ( ! l[ly fi%]-folk :o liv$ contemporane\sly ) ! mak]s ( ! highly f9i%$ poli%$ implem5ts ( ,d5m>k1 :ile ! o!rs are unf9i%$ implem5ts ?r[n away dur+ ! manufacture on acc\nt ( flaws or accid5tal fractures4 ,! difficulty is increas$ :5 we take into acc\nt ! great physical & fauni/ic *anges :i* occurr$ betwe5 ,paloli?ic & ,neoli?ic times4 ,! c\ntry 0 und\bt$ly m elevat$ ?an x is at pres5t dur+ portions if n dur+ ! :ole ( ,paloli?ic times1 z %[n by ! appe>ance ( ! great mammals 9 ,brita91 ! discov]y ( _! rema9s b5ea? sea-level1 & especially ! occurr5ce ( rema9s 9 ! cav]ns ( rocky isl&s su* z ^? ( ! ,bri/ol ,*annel1 :]e !y c\ld n possibly h exi/$ unless ! pres5t isl&s 7 connect$ ) ! ma9l&4 ,! fossils ( ! times betwe5 ! ,glacial p]iod & ! ,neoli?ic p]iod indicate v>iations ( climatic conditions4 ,^u ?is po9t ,i _c d bett] ?an quote ! words ( ,sir ,john ,evans 9 8 ,presid5tial ,address to ! ,briti% ,association at ,toronto#aag4 ,at ,hoxne ! int]val betwe5 ! deposit ( ! ,b\ld] clay & ( ! implem5t-be>+ b$s is di/9ctly prov$ to h witness$ at lea/ two notewor?y *anges 9 climate4 ,! b$s imm$iately repos+ on ! clay are *>act]is$ by ! pres5ce ( ald] 9 abundance1 ( hazel1 & yew1 z well z by t ( num]\s fl[]+ plants indicative ( a temp]ate climate v diff]5t f t "u :i* ! ,b\ld] clay itself 0 =m$4 ,above ^! b$s *>act]is$ by temp]ate plants1 comes a ?ick & m rec5t s]ies ( /rata1 9 :i* leaves ( ! dw>f ,arctic will[ & bir* ab\nd1 & :i* 7 9 all probability deposit$ "u conditions l ^? ( ! cold regions ( ,sib]ia & ,nor? ,am]ica4 ,at a high] level1 & ( m rec5t date ?an ^!--f :i* !y are entirely di/9ct--are ! b$s conta9+ ! ,paloli?ic implem5ts1 =m$ 9 all probability "u conditions n ess5tially diff]5t f ^? ( ! pres5t day4 ,footnote #aag3 ,report ,brit4 ,assoc4 = #ahig1 p4 #ac4 ,,*apt] ,,xxix4 ,,! ,,=e/ ,,p]iod4 ,subsequ5tly to ,paloli?ic times1 ! physical conditions ov] ,eurasia *ang$ greatly1 & at ! comm5cem5t ( ,neoli?ic times ! conditions 7 fav\rable = ! gr[? ( =e/s ov] wide regions ( t cont95t4 ,at ! comm5cem5t ( ! ,=e/ p]iod ! physical conditions 7 v mu* ! same z !y are at pres5t1 ?\gh m9or *anges h ( c\rse tak5 place s9ce !n1 includ+ probably a subm]g5ce ( l>ge p>ts ( ,brita9 to a dep? ( ab\t fifty feet b5ea? its =m] level1 z indicat$ by ! exi/5ce ( ,neoli?ic subm]g$ =e/s r\nd _m p>ts ( our coa/-l9es4 ,! ,=e/ p]iod may be be/ subdivid$ = local purposes by ref]5ce to ! civilisation ( mank9d at diff]5t times1 & 9 ?is way we obta9 ! foll[+ divisions3 ,hi/oric ,iron age4 ,prehi/oric ,iron age4 ,bronze age4 ,neoli?ic age4 ,a classification may also be bas$ ^u *anges 9 ! flora4 ,9 ,d5m>k ! peat deposits ( ?is age are divisible into five lay]s1 *>act]is$ by diff]5t dom9ant =ms ( trees4 ,^! are z foll[s 9 desc5d+ ord]3 ,fif? lay]3 ,bee* 444 ,iron age ,f\r? lay]3 ,ald] ,?ird lay]3 ,oak 444 ,bronze age ,second lay]3 ,scot* ,firs 444 ,neoli?ic age ,l[e/ lay]3 ,popl>4 ,9 our own c\ntry ! =e/ gr[? has be5 mu* int]f]$ ) by man1 b ! l[] f5l& peat gives a good example ( ! mat]ial =m$ by =e/ gr[?4 ,x is n necess>y to t\* on ! v>i\s accumulations :i* are n[ be+ =m$ 9 diff]5t p>ts ( our isl&1 except to rem>k t ! deposits ( ! ,=e/ p]iod give indications ( e>?-movem5ts on a small scale1 :i* is well se5 9 ! f5l&1 :]e ! =e/ peat is cov]$ 9 places by a butt]y clay ) ,scrobicul>ia pip]ata indicat+ subm]g5ce1 & above ?is is a m>% peat4 ,! flora & fauna ( ! ,=e/ p]iod are practically ^? ( ! pres5t day1 ?\gh ! l>g] =ms ( mammalia h disappe>$ "o by "o4 ,! ,iri% elk & ,bos primog5ius probably became ext9ct e>ly 9 ! p]iod1 :ile z f> z ,brita9 is conc]n$ ! wolf1 be>1 & beav] h disappe>$ )9 hi/oric times4 ,! relics ( man des]ve pass+ notice4 ,! ,neoli?ic p]iod is *>act]is$ by ! abs5ce ( metal in/rum5ts1 ?\gh ^? made ( /one 7 mu* m highly f9i%$ ?an ^? ( ,paloli?ic times1 & 7 (t5 gr\nd & poli%$4 ,! fir/ metal :i* 0 l>gely work$ 0 bronze1 :i* gradually replac$ /one1 ?\gh /one 0 ext5sively us$ 9 ! ,bronze age1 z indicat$ by ! imitation ( bronze implem5ts 9 /one4 ,! ,bronze age 9 turn 0 replac$ by ! ,prehi/oric iron age2 at fir/1 :5 iron 0 sc>ce1 bronze implem5ts 7 m]ely tipp$ ) iron1 b ultimately ! "o metal 0 practically replac$ by ! o!r4 ,! date ( ! ,paloli?ic p]iod is unkn[n2 no approximate date c be satisfactorily assign$ to x1 b v>i\s calculations1 f\nd$ on diff]5t data1 h be5 made z to ! age ( ! ,neoli?ic p]iod1 & sev]al ( !m agree 9 plac+ x at ab\t #gjjj ye>s f ! pres5t "t4 ,x w be se5 t no sudd5 & viol5t *ange m>ks ! incom+ ( ! human race1 :i* to ! geologi/ is b "o ( a l>ge numb] ( ev5ts :i* h foll[$ ea* o!r 9 unbrok5 sequ5ce1 & accord+ly ! ?read ( ! /ory :]e ab&on$ by ! geologi/ is tak5 up by ! antiqu>y1 & pass$ on by him to ! hi/orian#aah4 ,footnote #aah3 ,! /ud5t may obta9 in=mation conc]n+ ! ,neoli?ic age 9 ,brita9 9 ,boyd ,dawk9s's ,e>ly ,man 9 ,brita92 ,sir ,j4 ,evans' ,e>ly ,/one ,implem5ts ( ,great ,brita91 & ,sir ,j4 ,lubbock's ,prehi/oric ,times4 ,9 ! latt] "w he w f9d a good acc\nt ( ! ,neoli?ic rema9s ( ,d5m>k & ( ! ,swiss ,lake dwell+s4 ,= in=mation conc]n+ ! ,bronze age he %\ld consult ,evans' ,anci5t ,bronze ,implem5ts ( ,great ,brita94 ,! v>i$ ,dani% antiquities ( ,neoli?ic & ,bronze ages are figur$ 9 ,h4 ,p4 ,mads5's ,antiquits ,prhi/oriques du ,danem>k4 ,! ,prehi/oric fauna ( ! f5l&s is describ$ 9 ,sir ,r4 ,ow5's ,hi/ory ( ,briti% ,fossil ,mammals & ,birds4 ,,*apt] ,,xxx4 ,,rem>ks ,,on ,,v>i\s ,,que/ions4 ,!re are _m problems connect$ ) geology :i* c only be solv$ by detail$ /udy ( ! /ratifi$ rocks1 & :5 solv$ ! pr9ciples ( ! sci5ce w be m fully elucidat$4 ,9 ! pres5t /ate ( our k "s ( ^! problems are ripe = discussion1 o!rs c m]ely be indicat$1 :ile o!rs aga9 h probably rema9$ hidd51 ?\gh x w be ! task ( ! geologi/ ( ! future to cle> !m up4 ,among ! _m que/ions :i* dem& k ( /ratigraphical geology = _! "r und]/&+ are ! foll[+1 :i* w be briefly consid]$ 9 ?is *apt]3--! *anges 9 ! position ( l& & sea 9 pa/ times1 & ! gr[? ( cont95ts2 ! replacem5t ( a s*ool ( uni=mit>ianism by "o ( evolutionism2 & ! duration ( geological "t4 ,*anges 9 ! position ( l& & sea4 ,c]ta9 physici/s h arriv$ at ! conclusion t ! g5]al position ( our oceans & cont95ts 0 det]m9$ at a v e>ly p]iod 9 ! e>?'s hi/ory1 & t ! *anges :i* h occurr$ 9 _! position s9ce !n h be5 comp>atively insignificant4 ,! wide ext5t ( l& ov] :i* /ratifi$ rocks are di/ribut$ at once indicates t f ! po9t ( view ( ! geologi/ ! *anges h be5 v important1 & x is wor? inquir+ :e!r !y are n suffici5tly important to prove t ! primitive oceans & cont95ts h und]gone s mu* alt]ation z to be unrecognisable4 ,"s au?orities1 :ile recognis+ ! great *anges :i* h occurr$ 9 ! relative position ( l& & sea dur+ ^? p]iods ( :i* geologi/s h direct in=mation1 suppose t ! *anges took place to a l>ge degree 9 c]ta9 'critical areas' bord]+ ! m /able areas ( p]man5t ocean on ! "o side & p]man5t l& on ! o!r4 ,9 discuss+ ! "q ( g5]al p]man5ce ( l& & ocean regions x w be conv5i5t to comm5ce ) a /udy ( ! pres5t l& areas1 & at ! outset we may take into consid]ation ! pres5t di/ribution ( m>9e s$im5t ov] diff]5t p>ts ( ! l&1 us+ ! la/ edition ( ,m4 ,jules ,m>c\'s geological map ( ! _w = ! purpose#aai4 ,a glimpse at ?is map indicates t m ?an half ( ! l& areas are occupi$ by rocks :i* are z yet unkn[n 7_m ( :i* may be m>9e s$im5ts71 or by cry/all9e s*i/s ( :i* ! mode ( orig9 has n yet be5 fully expla9$1 s t a l>ge "p ( ,c5tral ,asia1 ! int]ior ( ,africa1 & ( ,s\? ,am]ica may h exi/$ z l& f v e>ly times1 & ! same may be said ( small] portions ( ,europe & ,nor? ,am]ica4 ,actual obs]vation ( a geological map !re=e indicates ! possibility t ab\t half ( ! l& surfaces may h exi/$ z su* ?r\gh v long p]iods1 b ?\gh !re is a possibility ( ?is1 ! probability is n v great4 ,! unkn[n regions1 z rem>k$ above1 may consi/ to a consid]able ext5t ( m>9e s$im5ts1 & ! exi/5ce ( isolat$ pat*es ( late ,palozoic & ( ,mesozoic /rata 9 ! he>t ( ,c5tral ,asia1 po9ts to ! subm]g5ce ( mu* wid] regions ?an ^? 9 :i* ^! isolat$ pat*es h be5 f\nd4 ,aga91 ! "* ( ! s$im5ts :5 !y abut aga9/ ! cry/all9e s*i/s frequ5tly proves t ^! s$im5ts once ext5d$ fur!r ov] ! cry/all9e s*i/s1 & h s9ce be5 remov$ by d5udation1 s t ev5 if we assume t ! cry/all9e s*i/s are all ( v e>ly date1 & n necess>ily =m$ 9 any case f m>9e s$im5ts1 we _c suppose t all ! area occupi$ by !m has exi/$ z l& = long p]iods ( "t4 ,on ! o!r h&1 ! major "p ( ,europe & ,nor? ,africa1 ext5sive tracts 9 ,asia1 ! great] "p ( ,au/ralia1 a v l>ge "p ( ,nor? ,am]ica & consid]able tracts ( ,s\? ,am]ica give pro(s ( hav+ be5 occupi$ by ! oceans 9 ,palozoic & lat] times4 ,footnote #aai3 ,a r$uc$ copy ( ?is map w be f\nd opposite ! title-page ( ! fir/ volume ( ,pr(4 ,pre/wi*'s ,geology4 ,x may be answ]$ t mo/ ( ^! regions conta9+ m>9e s$im5ts occur 9 critical areas1 :i* h und]gone a c]ta9 am\nt ( oscillation ow+ to e>?-movem5ts1 & t ! int]ior p>ts ( ! great cont95tal masses h be5 practically /ation>y4 ,b if ^! l&s _h be5 l&-areas ?r\gh geological ages !y mu/ h be5 act$ ^u by ! ag5ts ( suba]ial d5udation1 ?r\gh\t ^! ages1 & long ago r$uc$ to p5epla9s#abj unless ! action ( ^! suba]ial ag5ts 0 c\nt]act$ by t ( elevat+ =ces1 b if ^! =ces 7 suffici5t to c\nt]act ! action ( suba]ial d5udation ?r\gh c\ntless ages1 !y 7 also suffici5t to raise ext5sive tracts ( l& above sea-level1 & mat]ially to alt] ! di/ribution ( l& & sea1 & if elevation c\ld g on to ?is ext5t1 :y n also depression8 ,footnote #abj3 ,a t]m propos$ by ,pr(4 ,w4 ,m4 ,davis = a ne>ly level surface ( suba]ial d5udation1 z oppos$ to a pla9 ( m>9e d5udation4 ,proce$+ a /ep fur!r1 & exam9+ ! "* ( ! s$im5ts z well z _! geographical di/ribution1 we f9d fur!r evid5ce ( great cru/-movem5ts4 ,x has be5 urg$ t deep-wat] s$im5ts d n occur among/ ! /rata f\nd on ! cont95ts1--t !re are no repres5tatives ( ! abysmal deposits ( rec5t ocean floors among/ ! /rata ( ! geological column#aba1 b ! rese>*es ( ! la/ two decades h br\ght to light =am9if]al & radiol>ian deposits1 pt]opodal deposits1 & possibly deep-sea clays1 :i* are comp>able ) ^? 9 process ( =mation at great dep?s 9 exi/+ oceans1 & ?\gh ! pro(s ( _! deep-sea orig9 are n always z full z might be desir$ 9 ! case ( ! old] rocks#abb1 we c speak ) great] c]ta9ty :5 we exam9e ^? ( ,t]ti>y age1 & if ! deep-sea accumulations ( ?is late date c be uplift$ above sea-level1 ?is is mu* m likely to h occurr$ ) ^? ( pa/ times4 ,:5 a deposit l ! radiol>ian rock ( ,b>badoes1 ! deep-wat] "* ( :i* has be5 conclusively prov$1 c be elevat$ into l& s9ce ,mioc5e or possibly ,plioc5e times1 x is evid5t t ! cru/-movem5ts h be5 suffici5t to produce ! mo/ pr(\nd *anges 9 ! di/ribution ( l& & sea dur+ ! long ages :i* are kn[n to u4 ,ano!r argum5t aga9/ ! occurr5ce ( ext5sive *anges has be5 d]iv$ f an exam9ation ( ^? isl&s :i* are spok5 ( z oceanic isl&s4 ,/rictly speak+ an oceanic isl& is "o 9 :i* ! pres5t fauna & flora give indications ( _! introduction by transport across int]v5+ sea1 & no indications ( ! exi/5ce ( =ms ( life :i* inhabit$ x :5 x 0 once unit$ to a cont95t2 x may be inf]r$ ) a consid]able degree ( c]ta9ty t ^! isl&s h be5 isolat$ = long p]iods ( "t4 ,x has be5 /at$ t ^! oceanic isl&s nev] conta9 m>9e s$im5ts ( any consid]able degree ( antiquity1 & t !re are !re=e no traces ( =m] cont95ts ov] ^? wide tracts ( ocean :i* are occupi$ by oceanic isl&s4 ,! evid5ce is ( a negative "*4 ,! isl&s w\ld be less likely to exhibit anci5t s$im5ts ?an cont95ts1 = be+ ne> ! ocean1 !y w\ld be readily subm]g$1 & ! old] deposits mask$ by new] ones1 ?\gh ?is ne$ n necess>ily acc\nt = ! entire abs5ce ( anci5t rocks among/ !m4 ,! dang] ( ! argum5t lies 9 ! fact t we d n yet "k h[ f> ^! old rocks really are abs5t1 z ! geology ( ! oceanic isles has n be5 fully explor$ f ?is po9t ( view1 & already sev]al cases ( ! ass]t$ pres5ce ( anci5t rocks on ^! isl&s h be5 record$4 ,footnote #aba3 ,see ,mr ,a4 ,r4 ,wallace's ,isl& ,life4 ,footnote #abb3 ,see *apt] ,,ix4 ,! argum5t d]iv$ f ! pres5t di/ribution ( organisms is f> too complex to be discuss$ "h1 & ! /ud5t is recomm5d$ to read a ma/]ly review ( ! evid5ce 9 ,dr ,w4 ,t4 ,blan=d's ,presid5tial ,address to ! ,geological ,society 9 #ahij1 on ! "q ( ! ,p]man5ce ( ,ocean ,bas9s#abc4 ,aft] review+ ! evid5ce furni%$ by a /udy ( mod]n di/ribution he concludes t x is f> too contradictory to be receiv$ z pro( ( ! p]man5ce ( oceans & cont95ts4 ,footnote #abc3 ,qu>t4 ,j\rn4 ,geol4 ,soc41 vol4 ,,xlvi41 ,proc41 p4 #ei4 ,! exi/5ce ( =m] ext5sive l& tracts ov] regions n[ occupi$ by sea is naturally m difficult to prove ?an t ( sea ov] l&1 z we dep5d ^u inf]5ce r ?an actual obs]vation to a mu* great] degree ?an :5 consid]+ ! p]man5ce ( cont95ts1 nev]!less a consid]able am\nt ( indirect evid5ce 9 fav\r ( ! exi/5ce ( widespread l& tracts ov] our pres5t ocean regions has be5 accumulat$ & w be briefly notic$4 ,we may take fir/ ! evid5ce d]iv$ f ! nature ( s$im5ts1 & aft]w>ds t :i* has be5 acquir$ by /udy+ di/ribution ( organisms 9 pa/ times4 ,! indications ( exi/5ce ( an ext5sive tract ( cont95t ov] ! ,nor? ,atlantic ,ocean1 dur+ ,palozoic times h already be5 consid]$1 & x 0 se5 t ! ?9n+ out ( ! ,palozoic s$im5ts :5 trac$ away f ! pres5t ,atlantic bord]s 9 an ea/]ly direction ov] ,europe & 9 a we/]ly "o ov] ,nor? ,am]ica po9t$ to ! exi/5ce ( ?is ,palozoic ',atlantis1' z ma9ta9$ by ,pr(4 ,hull 9 8 "w1 ,contributions to ! ,physical ,hi/ory ( ! ,briti% ,isles4 ,?is writ] gives "s reasons = suppos+ t ! cont95tal mass began to break up t[>ds ! end ( ,palozoic times1 ?\gh x is n cle> t complete replacem5t ( l& by sea occurr$1 & ! nature ( ! ,weald5 deposits has be5 po9t$ to z evid5ce ( ! exi/5ce ( an ext5sive tract ( l& to ! we/ ( ,brita9 dur+ ! ,cretace\s p]iod4 ,! ,palontological evid5ce 9 fav\r ( de/ruction ( anci5t cont95tal areas & _! replacem5t by ! sea is m satisfactory ?an t :i* is bas$ on physical gr\nds4 ,! di/ribution ( ! ,glossopt]is flora ( ! ,p]mo-,c>bonif]\s p]iod po9ts to ! =m] exi/5ce ( a great s\!rn cont95t1 includ+ ! sites ( ,au/ralia1 ,india1 ,s\? ,africa & ,s\? ,am]ica1--! ,gondwanal& ( ,pr(4 ,e4 ,suess#abd4 ,footnote #abd3 ,on ?is "q & t ( ! o!r de/roy$ cont95tal areas not$ "h1 see ,w4 ,t4 ,blan=d's ,presid5tial ,address1 loc4 cit4 ,aga91 a /udy ( ,jurassic & ,cretace\s faunas has l$ palontologi/s to conclude t !re 0 a connexion betwixt ,s4 ,africa & ,india 9 ,mesozoic times across a portion ( ! area n[ occupi$ by ! ,indian ,ocean1 & also betwe5 ,s4 ,africa & ,s4 ,am]ica1 & ^! inf]5ces are support$ by /udy ( ! di/ribution ( exi/+ =ms4 ,! sudd5 appe>ance ( ! ,dicotyl$on\s ,angiosp]ms 9 ,upp] ,cretace\s rocks has also be5 us$ z evid5ce ( de/ruction ( consid]able tracts ( l& subsequ5tly to ,upp] ,cretace\s times1 & !re is a c]ta9 am\nt ( evid5ce 9 fav\r ( ! exi/5ce ( ?is l& 9 ! nor? pol> region1 9 an area n[ l>gely occupi$ by wat]1 ?\gh relics ( x are left1 z ! ,f>oe ,isles1 ,spitsb]g51 ,novaya ,zembla & ,franz ,josef ,l&4 ,i _c conclude ! consid]ation ( ! "q ( p]man5ce ( oceans & cont95ts m fitly ?an by quot+ f ,dr ,blan=d's address4 ,he says1 ,!re is no evid5ce :atev] 9 fav\r ( ! extreme view accept$ by "s physici/s & geologi/s t e ocean-b$ n[ m ?an #ajjj fa?oms deep has always be5 ocean1 & t no "p ( ! cont95tal area has ev] be5 b5ea? ! deep sea4 ,n only is !re cle> pro( t "s l&-areas ly+ )9 cont95tal limits h at a comp>atively rec5t date be5 subm]g$ ov] #ajjj fa?oms1 :il/ sea-bottoms n[ ov] #ajjj fa?oms deep mu/ h be5 l& 9 "p ( ! ,t]ti>y era1 b !re are a mass ( facts bo? geological & biological 9 fav\r ( l&-connexion hav+ =m]ly exi/$ 9 c]ta9 cases across :at are n[ broad & deep ocean#abe4 ,footnote #abe3 ,loc4 cit41 ,proc4 p4 #ajg4 ,gr[? ( cont95ts4 ,:atev] view z to ! g5]al p]man5ce ( cont95ts & oceans be ultimately e/abli%$1 ! occurr5ce ( widespread *anges 9 ! position ( l& & sea is indisputable1 & x is ( int]e/ = u to consid] ! nature ( ^! *anges 9 ! =mation ( cont95ts4 ,pr(4 ,j4 ,d4 ,dana has put =w>d a hypo!sis ( gr[? ( cont95ts by a process ( accretion1 caus+ dim9ution 9 ! oceanic areas1 :i* at ! same "t became deep]3 su* gr[? ne$ n always take place 9 exactly ! same way1 & /udy ( ! di/ribution ( ! /rata ( ! ,nor? ,am]ican cont95t sugge/s t ! gr[? !re 0 endog5\s1 ! old] rocks ly+ to ! we/ & nor? =m+ a horse%oe %ap$ cont95t enclos+ a gulf-l prolongation ( ! ,atlantic1 :i* became contract$ by deposition & uplift 9 successive geological p]iods1 ?\gh x is /ill p>tly exi/5t z ! ,gulf ( ,mexico4 ,! ,eurasian cont95t1 especially its we/]n portion1 sugge/s m irregul> gr[? ar\nd scatt]$ nuclei ( old] rocks1 ?\gh ! process is n complet$1 & _m gulf-l prolongations1 z ! ,baltic & ! ,m$it]ranean1 /ill rema9 z wat]-tracts1 :i* h n yet be5 add$ to ! cont95ts4 ,al?\gh ext5sive additions to cont95ts may be & no d\bt are (t5 l>gely due to epeirog5ic movem5ts1 ! influ5ce ( orog5ic movem5ts on cont95t-=mation is v pron\nc$4 ,z ! result ( orog5ic movem5ts1 ! rocks ( portions ( ! e>?'s cru/ become greatly compress$1 & give rise to masses :i* readily resi/ d5udation2 moreov]1 ^! comp>atively rigid masses1 z %[n by ,m4 ,b]tr&1 t5d to und]go elevation along ! same l9es z ^? :i* =m$ ! axes ( previ\s elevations1 & accord+ly aft] a cont95tal area has und]gone d5udation = a consid]able p]iod1 ! upl&s consi/ ( rocks :i* h und]gone orog5ic di/urbance1 :ile ! tracts ( gr\nd :i* are occupi$ by rocks :i* h n suff]$ di/urbances ( ?is "*1 ev5 if orig9ally uplift$ f> above sea-level1 t5d to be de/roy$1 & ultimately occupi$ by tracts ( ocean4 ,/umps ( =m] m\nta9 *a9s may be aga9 & aga9 e/abli%$ z nuclei ( cont95ts & z e p]iod ( orog5ic movem5t w add to ! numb] ( ^! nuclei1 ! cont95tal areas mu/ 9 c\rse ( "t become m complex 9 /ructure4 ,moreov]1 z "s areas are affect$ by orog5ic movem5ts to a great] ext5t ?an o!rs1 ! complexity ( diff]5t cont95tal masses w v>y4 ,?us1 we/]n ,europe has be5 affect$ by orog5ic movem5ts dur+ _m p]iods s9ce ! comm5cem5t ( ,cambrian times & its /ructure is extremely complex1 :ile ! c5tral & we/]n p>ts ( ,russia h n be5 subject$ to viol5t orog5ic di/urbances s9ce ,cambrian times1 & accord+ly we f9d ! /ructure ( t area comp>atively simple2 ! great] "p ( ,africa seems to h escap$ ^! movem5ts s9ce remote times1 & ! /ructure ( t cont95t is extremely simple :5 comp>$ ) ! ,eurasian cont95tal tract4 ,x ne$ h>dly be /at$ t ! =mation ( ext5sive *a9s compos$ ( volcanic mat]ial1 by accumulation ( lavas & a%es on ! e>?'s surface1 may give & (t5 has giv5 rise to m rigid tracts1 :i* w br+ ab\t ! same effects z ^? produc$ by orog5ic di/urbance z illu/rat$ on a small scale by ! ,l[] ,palozoic volcanic rocks ( ,cambria & ,cumbria4 ,uni=mit>ianism & ,evolution4 ,accord+ to ! extreme uni=mit>ian views held by "s geologi/s1 ! ag5ts :i* are 9 op]ation at ! pres5t day are simil> 9 k9d & 9 int5sity to ^? :i* 7 at "w 9 pa/ times1 ?\gh no geologi/ w be f\nd :o is suffici5tly bold to ass]t t ?is holds true = all p]iods ( ! e>?'s hi/ory1 b only = ^? ( :i* ! geologi/ has direct in=mation d]iv$ f a /udy ( ! rocks1 & he is cont5t to foll[ 8 ma/] ,hutton 9 ignor+ p]iods ( :i* he _c f9d records among/ ! rocks4 ,! mod]n geologi/1 h[ev]1 :ile rightly reg>d+ ! rocks z 8 pr9cipal s\rce ( in=mation f9ds t he _c af=d to ignore ! evid5ce furni%$ by ! physici/1 *emi/1 a/ronom] & biologi/1 :i* ?r[s light ^u ! hi/ory ( p]iods f> e>li] ?an ^? ( :i* he has any records pres]v$ among/ ! out] portions ( ! e>? itself1 j z ! mod]n hi/orian is n cont5t ) writt5 records1 b mu/ turn to ! 'prehi/oric' ar*ologi/ & geologi/ = in=mation conc]n+ ! hi/ory ( e>ly man ^u ! e>?4 ,int]pret+ ! scope ( geology 9 ?is g5]al way1 rigid uni=mit>ianism mu/ be ab&on$4 ,assum+ t ! t5ets ( ! evolutioni/ s*ool are g5]ally true1 ! "q is1 h[ f> does ?is affect ! geologi/ 9 8 /udy ( ^? p]iods ( :i* we h def9ite records among/ ! rocks8 ,?is is a "q :i* _c readily be answ]$ at ! pres5t day1 = our /udy ( ! rocks is n suffici5tly f> advanc$ to enable u to po9t out effects among/ ! old] rocks :i* 7 cle>ly caus$ by ag5ts work+ ) great] int5sity ?an !y d at pres5t1 b z1 on ! o!r h&1 we _c prove t ^! effects are due to ag5ts work+ ) no great] int5sity ?an t :i* n[ m>ks ^! op]ations1 x is unphilosophical to assume ! latt]4 ,no /ud5t ( sci5ce at ! pres5t day w\ld /ate t because !re has be5 no obs]v$ case ( incom+ ( fre% species )9 ! "t t man has actually obs]v$ ! pres5t faunas & floras1 ! hypo!sis ( evolution ( organisms is disprov$1 = ! "t ( obs]vation has be5 too %ort1 & simil>ly ! "t :i* has elaps$ s9ce ! =mation (1 say1 ! ,cambrian rocks may h be5 too %ort1 z comp>$ ) ! "t :i* has elaps$ s9ce ! =mation ( ! e>?1 to all[ ( any important *ange 9 ! op]ation ( ! geological ag5ts4 ,leav+ out ( acc\nt1 = ! mom5t1 ! actual evid5ce :i* has be5 d]iv$ f a /udy ( ! rocks1 we may briefly consid] ! !oretical gr\nds ^u :i* ! sub/itution ( an evolutioni/ s*ool ( geology = "o ( uni=mity has be5 sugge/$#abf4 ,! pr9cipal s\rces ( en]gy :i* h ex]t$ an influ5ce ^u geological *anges are ! heat receiv$ f ! sun & t giv5 (f f ! e>? itself1 bo? ( :i* mu/ h dim9i%$ 9 quantity ?r\gh\t geological ages4 ,to ! =m] s\rce we l>gely owe climatic *anges & ! op]ations ( d5udation1 & accord+ly ( deposition2 to ! latt]1 ^? ( e>?-movem5t & vulcanicity4 ,x by no means foll[s t because ! ag5ts 7 once pot5tially m p[]ful ?an n[1 !y w\ld necess>ily produce great] effects1 = t dep5ds to "s ext5t ^u ! v>i\s conditions :i* prevail$ at diff]5t times4 ,to give an example3--if !re _h at any "t be5 a univ]sal ocean ( consid]able dep?1 h[ev] active ! ag5ts ( d5udation 7 !n1 !y c\ld produce no effect :atev]1 hav+ no?+ to "w ^u2 to take a less extreme case1 if our cont95ts at any pa/ "t 7 small] & less elevat$ ?an at pres5t1 ag5ts ( d5udation work+ ) great] int5sity ?an t ( ! pres5t ag5ts ne$ n necess>ily h produc$ a great] am\nt ( d5udation ?an t :i* is go+ on at ! pres5t day4 ,aga91 let u consid] vulcanicity3 ,x is z c]ta91 says ,"l ,kelv91 t !re is less volcanic en]gy 9 ! :ole e>? ?an !re 0 a ?\s& ye>s ago1 z x is t !re is less gunp[d] 9 a ',monitor' aft] %e has be5 se5 to dis*>ge %ot & %ell1 :e!r at a ne>ly equable rate or n1 = five h\rs )\t receiv+ fre% supplies ?an !re 0 at ! beg9n+ ( ! action4 ,b x does n foll[ t ! manife/ations ( volcanic activity 7 necess>ily m viol5t 9 e>ly geological times ?an n[1 = ! degree ( viol5ce w\ld be affect$ by o!r ?+s ?an ! volcanic en]gy1 su* z ! ?ickness ( ! e>?'s cru/4 ,footnote #abf3 ,! /ud5t may consult an int]e/+ article by ,pr(4 ,sollas be>+ on ?is subject4 ,see ,geol4 ,mag4 ,dec4 #b1 vol4 ,,iv4 p4 #a4 ,& n[1 let u consid] briefly ! *>act]s ( ! rocks ( ! cru/1 to see if !y ?r[ any light ^u ?is "q4 ,! e>lie/ s$im5ts ( :i* we h any c]ta9 k resemble 9 a /rik+ mann] ^? =m$ at ! pres5t day1 & !y seem to h be5 =m$ "u v mu* ! same conditions1 ?\gh fur!r "w may %[ t !re 7 some:at diff]5t conditions :i* did produce def9ite diff]5ces 9 ! *>act]s ( ! e>li] /rata#abg4 ,our k ( e>?-movem5t & vulcanicity :i* took place 9 pa/ times is /ill too small to enable u to draw any c]ta9 conclusions connect$ ) ! subject "u discussion f x4 ,p]haps ! mo/ sugge/ive indication ( "o set ( conditions hav+ be5 g5]ally simil> 9 ^? e>ly p]iods ( :i* we h def9ite records among/ ! rocks is furni%$ by /udy ( pa/ climate4 ,if we accept ! nebul> hypo!sis z a />t+ po9t1 we mu/ admit t 9 ! e>ly /ages ( ! e>?'s hi/ory ! temp]ature ( ! surface1 :i* w\ld !n be l>gely dep5d5t ^u ! am\nt ( heat giv5 out f ! e>? itself z well z ^u t receiv$ f ! sun1 mu/ h be5 mu* high] ?an x is at ! pres5t day1 & inde$ ! m]e dim9ution ( ! am\nt ( heat receiv$ f ! sun w\ld probably be suffici5t to acc\nt = a v m>k$ l[]+ ( ! temp]ature4 ,besides ?is *ange ( temp]ature1 result+ 9 gradual l[]+ ( temp]ature ov] ! :ole e>?'s surface1 we h o!r *anges dep5d5t ^u diff]5t conditions1 z prov$ by ! fact1 t !re h be5 alt]nations ( glacial & g5ial p]iods4 ,if ! g5]al temp]ature _h be5 v high 9 ! e>ly p]iods ( :i* we h actual records1 ! oscillations w\ld n be suffici5t to produce a l[]+ ( temp]ature suffici5t to cause glacial p]iods1 :]eas if x _h n be5 appreciably high] ?an n[1 glacial p]iods might be produc$4 ,?is may be repres5t$ diagrammatically4 ,footnote #abg3 ,on ?is matt] see ,teall1 ,j4 ,j4 ,h41 ',presid5tial ,address to ,section ,c1' ,report ( ! ,briti% ,association1 #ahic4 ,let a repres5t ! temp]ature at ! comm5cem5t ( e>?-hi/ory & b t necess>y = glaciation1 & bc ! lapse ( "t betwe5 !n & n[4 ,! curv$ l9e indicates ! gradual fall 9 temp]ature due to dim9ution ( ! am\nt ( heat1 :ile ! zigzag l9e repres5ts ! oscillations due to secul> climatic *anges4 ,if ! ,cambrian p]iod x occurr$ comp>atively soon aft] ! comm5cem5t ( e>?-hi/ory z %[n 9 fig4 ,a1 no glaciation c\ld be produc$1 ev5 dur+ p]iods :5 secul> *anges caus$ cold] conditions ?an ! mean1 :]eas if ! ,cambrian p]iod occurr$ at a "t v remote f ! comm5cem5t ( e>?-hi/ory z %[n 9 ,b1 glacial conditions c\ld be produc$ !n z n[1 = ! mean temp]ature1 z %[n by ! di/ance ( ! curve f ! l9e bc1 w\ld be practically z x n[ is4 ,! /udies ( ! la/ few decades h br\ght into prom95ce ! occurr5ce ( glacial p]iods 9 remote times1 probably 9 e>ly ,palozoic times2 & z f> z ! mean temp]ature ( ! e>?'s surface is conc]n$1 x w\ld appe>1 f ! k 9 our possession1 t matt]s 7 n v diff]5t 9 ^? e>ly times f :at !y n[ are4 ,illu/ration3 ,fig4 #be4 ,"s fur!r rem>ks w be made 9 subsequ5t p>agraphs conc]n+ ! p]iod ( ! e>?'s hi/ory at :i* ! geologi/ is fir/ furni%$ ) def9ite records1 b 9 ! meantime x may be obs]v$ t ! geologi/ w d well1 :5 work+ among/ ! /rata1 to consid] t ! m active op]ation ( ag5ts1 ev5 9 times ( :i* he has def9ite k1 may h produc$ effects :i* he %\ld be prep>$ to discov]1 z _! discov]y w\ld be ( consid]able importance1 & t he %\ld n be cont5t to inf] t because x has be5 prov$ t ag5ts op]at+ ) ! same int5sity z t :i* !y h at pres5t1 may h produc$ all ! effects :i* he c actually obs]ve1 !y !re=e necess>ily did produce !m4 ,recurr5ces4 ,absolute uni=mity ( conditions is impossible1 ev5 9 a s+le area4 ,e *ange :i* takes place ^u ! e>? produces conditions some:at dissimil> f ^? :i* previ\sly exi/$1 & ^! w leave _! effects ^u ! physiography ( ! area4 ,= ?is reason1 assum+ t ! conditions h gradually *ang$ f simpl] to m complex1 e p]iod ( "t w h be5 m>k$ by conditions :i* nev] prevail$ be=e or aft]w>ds1 & ^! w leave _! impress ^u ! deposits ( ! p]iod4 ,x is d\btful = in/ance1 z already rem>k$1 :e!r ! exact conditions :i* gave rise to ! ext5sive deposits ( vegetable matt] 9 ,c>bonif]\s times :i* n[ =m coal1 ev] occurr$ to a l ext5t 9 previ\s or subsequ5t p]iods1 & accord+ly1 ?\gh we h deposits ( coal ( o!r ages1 none are s ext5sive z ^? ( ! ,coal ,measures4 ,aga91 z ! /rata ( "o p]iod are l>gely compos$ ( d5ud$ p>ticles ( pre-exi/+ /rata1 :i* 7 d]iv$ directly or indirectly f igne\s rock1 ! soluble mat]ial exi/+ 9 ! igne\s rocks mu/ h be5 gradually elim9at$ unless re/or$ by o!r processes1 & we might expect to f9d t e>ly s$im5ts h1 on ! :ole1 a l>g] proportion ( soluble silicates ?an ! lat] ones4 ,besides ^! *anges1 !re are physical *anges :i* are recurr5t1 & cause conditions g5]ally simil> to pre-exi/+ ones to occur 9 an area aft] an int]val ( dissimil> ones4 ,we h se5 t deposits t5d to v>y accord+ to ! di/ance f ! coa/1 lime/one be+ succe$$ by mud1 ?is by s& & gravel1 & aft] subsid5ce ! s& & gravel are succe$$ by mud1 & t by lime/one4 ,^! *anges w produce "s effect ^u ! organisms1 & ! recurr5ce ( organisms is a well-kn[n ev5t1 ( :i* cases h be5 cit$ 9 a =m] *apt]4 ,aga9 we f9d1 z already po9t$ out1 recurr5ce ( climatic *anges1 ) alt]nation ( glacial & w>m] p]iods1 & ^! may h be5 v widespread1 & w\ld influ5ce ! o!r physical conditions1 z well z ! di/ribution ( ! organisms4 ,vulcanicity may h be5 m rife at "s p]iods ?an o!rs1 = in/ance !re seems1 9 ! pres5t imp]fect /ate ( our k1 evid5ce ( enfeebl$ vulcanicity 9 lat] ,mesozoic times1 & ( its r5ew$ activity 9 ,t]ti>y times4 ,aga91 orog5ic movem5ts seem to h occurr$ m ext5sively at "s times ?an o!rs1 z = in/ance 9 e>ly upp] ,palozoic times1 at ! end ( ! ,palozoic epo*1 & 9 e>ly ,t]ti>y times1 ?\gh ?is may also be an app>5t & n an actual tru?1 due to imp]fect k4 ,9 any case1 9 limit$ areas1 !re seem to h be5 alt]nations ( p]iods ( uplift accompani$ by m>k$ orog5ic movem5ts1 & ( widespread depression1 accompani$ by s$im5tation4 ,! subject ( rhy?mic recurr5ce is wor?y ( fur!r /udy4 ,?is recurr5ce 9 comb9ation ) evolution>y *ange may acc\nt = ! app>5t m>k$ diff]5ce betwe5 ,cambrian & ,precambrian times1 a diff]5ce :i* /rikes "s geologi/s z be+ too great to be acc\nt$ = z due to our ignorance only4 ,organic evolution4 ,?is subject is too wide = m ?an pass+ notice 9 a "w ( ?is "*4 ,! evid5ce ( ,palontology is ( extreme importance to ! biologi/1 & inde$1 ! way 9 :i* evolution ( organisms has occurr$ c only be actually demon/rat$ by ref]5ce to ,palontology1 & ! /udy ( ,palontology has already giv5 mu* in=mation conc]n+ ! l9es on :i* evolution has proce$$ 9 diff]5t gr\ps ( organisms4 ,x mu/ be rememb]$ t ! major divisions ( ! inv]tebrata 7 9 exi/5ce 9 v e>ly times2 inde$ repres5tatives ( mo/ ( !m are f\nd 9 ! rocks conta9+ ! e>lie/ kn[n fauna1 t ( ! ,ol5ellus b$s ( ,cambrian age4 ,if our pres5t views z to evolution be correct1 !re is no d\bt t ! p]iod :i* elaps$ betwe5 ! appe>ance ( life ^u ! globe & ! exi/5ce ( ! ,ol5ellus fauna mu/ h be5 v great1 possibly1 z ,huxley sugge/$1 mu* great] ?an t :i* has elaps$ betwe5 e>ly ,cambrian times & ! pres5t day4 ,if ?is be s1 h[ev] probable x is t we %all c>ry our k ( anci5t faunas f> back beyond ,cambrian times1 x is extremely improbable t we %all ev] get traces ( ! v e>lie/ faunas :i* occupi$ our e>?4 ,geological "t4 ,v>i\s attempts h be5 made to give num]ical e/imates ( ! lapse ( "t :i* occurr$ s9ce ! e>? 0 =m$1 or s9ce ! e>lie/ kn[n rocks 7 deposit$4 ,^! attempts may be class$ "u two heads1 namely1 ^? made by physici/s1 ma9ly on evid5ce obta9$ o!rwise ?an by a /udy ( ! rocks1 & ^? made by geologi/s by calculat+ ! mean rate ( d5udation & deposition ( ! rocks1 & e/imat+ ! av]age ?ickness ( ! rocks ( ! geological column4 ,! calculations ( physici/s z to ! age ( ! e>? v>y3--,"l ,kelv9 assign$ #bj1jjj1jjj ye>s z ! m9imum & #ajj1jjj1jjj z ! maximum duration ( geological "t4 ,pr(4 ,tait has halv$ ,"l ,kelv9's m9imum p]iod1 :ile ,pr(4 ,g4 ,d>w9 admits ! possibility ( ! lapse ( #ejj1jjj1jjj ye>s4 ,! e/imates made by geologi/s1 :i* w appeal m directly to ! geological /ud5t1 also v>y consid]ably1 ?\gh !y be> "s proportion to ^? :i* h be5 put =w>d by ! physici/s4 ,pr(4 ,s4 ,haughton#abh assign$ a p]iod ( #bjj1jjj1jjj ye>s = ! accumulation ( ! rocks ( ! geological column2 ,mr ,clifton ,w>d#abi "o ( #fb1jjj1jjj ye>s1 aft] /udy+ ! rocks ( ! ,engli% ,lake ,di/rict1 & all[+ = ! gaps 9 ! succession2 ,mr ,a4 ,r4 ,wallace#acj fur!r l[]s ! "t = ! =mation ( ! column to #bh1jjj1jjj ye>s2 ,sir ,a4 ,geikie#aca gives #gc1jjj1jjj ye>s z ! m9imum & #fhj1jjj1jjj z ! maximum2 :ile ,mr ,j4 ,g4 ,good*ild has lately#acb e/imat$ ! p]iod at ov] #gjj1jjj1jjj ye>s4 ,footnote #abh3 ,nature1 vol4 ,,xviii4 p4 #bfh4 ,footnote #abi3 ,w>d1 ,j4 ,c41 ',! ,physical ,hi/ory ( ! ,engli% ,lake ,di/rict1' ,geol4 ,mag4 ,dec #b1 vol4 ,,vi4 p4 #aaj4 ,footnote #acj3 ,wallace1 ,a4 ,r41 ,isl& ,life1 ,*ap4 ,x4 ,footnote #aca3 ,geikie1 ,sir ,a41 ',presid5tial ,address to ! ,briti% ,association1' ,report ,brit4 ,assoc41 #ahib4 ,footnote #acb3 ,good*ild1 ,j4 ,g41 ,proc4 ,roy4 ,soc4 ,ed9burgh1 vol4 ,,xiii4 p4 #bei4 ,int]e/+ z ^! figures are1 !y probably convey little to ! ord9>y read]1 & x is d\btful :e!r ! geologi/ is really affect$ by !m to any ext5t :5 pictur+ to himself ! va/ duration ( geological "t4 ,"o num]ical e/imate probably does impress him1 namely t made by ,croll z to ! date ( ! ,great ,ice ,age1 = if ! ,ice ,age be s remote z ,croll imag9$1 ! comm5cem5t ( e>?-hi/ory mu/ be inconceivably m remote2 z ,croll's e/imate is n g5]ally accept$1 x is d\btful h[ f> geologi/s are ?us influ5c$1 & probably ! fact :i* does impress !m mo/1 leav+ fossils out ( acc\nt1 is ! v little *ange :i* has occurr$ 9 hi/oric or ev5 9 prehi/oric times z comp>$ ) ! va/ *anges :i* are famili> to !m aft] /udy+ ! /rata ( ! geological column4 ,x is1 aft] all1 ! succession ( v>i$ faunas :i* really gives /ud5ts ( ! rocks ! mo/ conv9c+ pro( ( ! va/ p]iods ( geological "t4 ,if anyone d\bts ?is ass]tion1 let him consid] :at impression w\ld be made ^u him by obs]v+ ! sev]al ?\s& feet ( /rata ( ! column if none ( !m conta9$ any organisms4 ,cognisant z he is ( ! sl[ rate ( *ange ( exi/+ organisms1 ! fact t fauna has succe$$ fauna 9 pa/ times br+s home to him 9 an unmi/akeable mann] ! great antiquity ( ! e>lie/ fossilif]\s rocks1 & z our detail$ k ( ^! faunas increases ! impression ( great lapse ( "t is int5sifi$4 ,& if ! e>lie/ fossilif]\s rocks be ( su* va/ antiquity1 &1 z has be5 rem>k$1 ! p]iod ( _! =mation is comp>atively rec5t ) ref]5ce to ! actual comm5cem5t ( e>?-hi/ory1 ! latt] mu/ inde$ be inconceivably remote1 & num]ical e/imates c d b little to famili>ise u ) ! significance ( ! va/ "t :i* has roll$ by s9ce ! _w's bir?day4 ,,index4 ,abraum salts1 #bab olian rocks1 #bd1 #ii1 #ajj ,age1 def9ition (1 #fj ,albian s]ies1 #bcf1 #bch ,algonkian rocks1 #add ,amp?ill clay1 #bcb ,angel91 ,n4 ,p41 #afa1 #afb1 #afe ,aptian s]ies1 #bcf1 #bcg ,aque\s rocks1 #bd ,ar*an rocks1 #acb ,ardmillan s]ies1 #agj ,ardwick /age1 #aib ,ar5ace\s rocks1 #bi ,arvonian rocks1 #ada ,asaphus fauna1 #afe ,a%gill s]ies1 #afd1 #afe1 #afg-afi ,a%pr+ton s]ies1 #ahd ,a/ian s]ies1 #bef ,atlantis1 #bhc ,avel9e1 ,w4 ,t41 #afd ,ayme/ry lime/one1 #age1 #agf ,bag%ot b$s1 #bdd1 #bdf ,bajocian s]ies1 #bbg1 #bca ,bala lime/one1 #afg ,bala s]ies1 #afd ,b>r s]ies1 #agj ,b>r&e1 ,j41 #ec1 #ee1 #aei1 #afa1 #afc ,b>rois1 ,c41 #bci ,b>r[1 ,g41 #ach ,b>ton b$s1 #bdd ,ba? oolites1 #bbf ,ba?onian s]ies1 #bbg1 #bca ,b$1 #bg ,b$d+ plane1 #bg ,bell1 ,a41 #beg ,belt1 ,t41 #aec1 #afb ,bembridge b$s1 #bea ,b]tr&1 ,m41 #hg1 #bhf ,birkhill %ales1 #agg ,black ,jura1 #bbf ,blake1 ,j4 ,f41 #ach-adj ,blan=d1 ,w4 ,t41 #bjf1 #bjh1 #bag1 #bhb1 #bhd ,bonney1 ,t4 ,g41 #gf1 #ada1 #adb ,b\ld] clay1 #bfb ,brackle%am b$s1 #bdd ,brad=d clay1 #bcj ,break1 palontological1 #fa2 physical1 #fj ,bri/[1 ,h41 #bci ,brockram1 #baa ,brgg]1 ,w4 ,c41 #afa-afc ,brongni>t1 ,h41 #ah ,brongni>t1 ,c41 #bjj ,bronze age1 #bge-bgg ,br[n ,jura1 #bbf ,bunt] s&/one1 #bah1 #bbj-bbb ,bure valley b$s1 #bef ,butt]y clay1 #bgf ,ca]fai b$s1 #aeb1 #aed1 #aef ,calc>e\s rocks1 #bi ,caldicote s]ies1 #aci ,callaway1 ,c41 #ach-adj ,callovian s]ies1 #bbg1 #bcb ,cambrian faunas1 #aeh-afc ,cambrian sy/em1 #aeb-afc ,c>adoc s]ies1 #afe1 #afh-aga ,c>bonace\s rocks1 #bi ,c>bonif]\s fauna & flora1 #aii-bja ,c>bonif]\s lime/one1 #aib1 #aid1 #aie ,c>bonif]\s sy/em1 #aib-bja ,c>nic b$s1 #bbe ,catacla/ic rocks1 #bd ,cave man1 #bfh ,c5omanian s]ies1 #bcf ,c]atopyge fauna1 #afb ,*alk1 #bcf1 #bch1 #bci ,*alk m>l1 #bcf ,*emically-=m$ rocks1 #bi1 #aja ,*illes=d crag1 #bef ,*ronological t]ms1 #fj ,cla/ic rocks1 #bd ,climatic conditions1 #ajc1 #aab1 #bij1 #bia ,climatic zones1 9 ,jurassic times1 #bcc2 9 ,cretace\s times1 #bda ,clym5ian b$s1 #ahc ,coal1 #aif-aii ,coal measures1 #aib2 mode ( =mation (1 #aie-aii ,cobl5zian b$s1 #ahd ,collywe/on slate1 #bca ,colonies1 !ory (1 #ee ,contemporaneity ( /rata1 #dh ,cont95ts1 gr[? (1 #bhe-bhg ,cope1 ,e41 #bdi ,corallian s]ies1 #bbg1 #bcb ,corall9e crag1 #bef1 #beg ,cornbra%1 #bcj ,corn/ones1 #ahf ,c\t*i*+ s]ies1 #add ,crags1 #bef-bei ,cretace\s fauna & flora1 #bda-bdc ,cretace\s sy/em1 #bcf-bdc ,croll1 ,j41 #bfe1 #bie1 #bif ,crom] ,=e/ s]ies1 #ajj1 #bef1 #bei ,crom] till1 #bfb ,cuculla b$s1 #ahc ,cuvi]1 ,b>on ,g41 #ah1 #bj ,dalradian rocks1 #acg ,dana1 ,j4 ,d41 #bhe ,danian s]ies1 #bcf ,d>w91 ,c41 #bj1 #gf ,d>w91 ,g41 #bie ,daubre1 ,a41 #hh ,david1 ,t4 ,w4 ,e41 #bjf ,davis1 ,w4 ,m41 #beh1 #bhj ,dawk9s1 ,w4 ,b41 #bff1 #bfh1 #bgj1 #bgb1 #bgg ,deep-sea deposits1 #aji ,de ,hayes1 ,g4 ,p41 #ai ,de la ,be*e1 ,sir ,h41 #ib ,deposition1 ord] (1 #cg1 #aaf ,d]ivative rocks1 #bc ,devonian flora & fauna1 #ahi-aia ,devonian sy/em1 #ahc-aia ,dictyograptus fauna1 #afb ,dimetian rocks1 #ada ,dogg]1 #bbf ,d[ntonian b$s1 #age ,dwyka conglom]ate1 #bjf ,edw>ds1 ,f4 ,e41 #bej ,eifelian b$s1 #ahd ,encr9urus fauna1 #ahe ,englacial deposits1 #bfa ,entomis slates1 #ahc ,eoc5e fauna & flora1 #bdh1 #bdi ,eoc5e rocks1 #bdd-bej ,eozoon canad5se1 #adc ,ep>*an rocks1 #acb ,epeirog5ic movem5ts1 #cb ,epicla/ic rocks1 #bd2 simulation by catacla/ic rocks1 #ch1 #hj ,epo*1 def9ition (1 #fj ,e/u>9e s]ies1 #bcj ,e!ridge1 ,r41 #ai ,ett+%aus51 ,b>on von1 #bej ,evans1 ,sir ,j41 #bff1 #bgj1 #bgd1 #bgg ,evolution1 #bhg1 #bic ,fei/mantel1 ,o41 #bjh ,f5l&1 #bgf ,fluvio-glacial deposits1 #bfa ,=el& grits1 #ahd ,=e/ m>ble1 #bcj ,=e/ p]iod1 #bfj1 #bge-bgg ,fossils1 #db2 /rata id5tifiable by1 #dj2 mode ( occurr5ce (1 #dd2 relative value (1 #dg2 remani1 #eb2 geographical di/ribution (1 #ee2 z indicative ( physical conditions1 #ajd ,fossil zone1 #fg ,fo/]1 ,c4 ,le ,n41 #bci ,fox1 ,h41 #aie ,fre%wat] deposits1 #ajd2 di/9ction f m>9e1 #aje ,full]'s e>?1 #bcj ,fusul9a b$s1 #bja ,gala b$s1 #agg ,ganni/] /age1 #aib ,g>dn]1 ,j4 ,s41 #bej ,gault1 #bcf1 #bch ,geikie1 ,sir ,a41 #fj1 #hd1 #ie1 #abe1 #acj1 #acg1 #ada1 #adb1 #add1 #ahf1 #ahh1 #aii1 #bdg1 #bie ,geikie1 ,j41 #bfc ,girvan type1 #agj ,glacial deposits1 p]mo-c>bonif]\s1 #bjf2 ,plei/oc5e1 #bfj-bff ,glacial p]iod1 #bfj-bff ,gl5kiln %ales1 #afi1 #agj ,glossopt]is flora1 #bjg1 #bjh1 #bad ,godw9-,au/51 ,r4 ,a4 ,c41 #bj ,gondwana s]ies1 #bjg ,gondwanal&1 #bjg1 #bhd ,goniatite b$s1 #ahc ,good*ild1 ,j4 ,g41 #hg1 #acj1 #bfc1 #bie ,great ice age1 #bie1 #bif ,great oolite1 #bcj1 #bca ,gregory1 ,j4 ,g41 #beh ,gre51 ,a4 ,h41 #abb1 #aci1 #aic ,gre5s&1 ,l[]1 #bcf2 ,upp]1 #bcf ,groom1 ,t4 ,t41 #agh ,g%ellian b$s1 #aic1 #bja ,hamp%ire bas91 #bde ,hangman grits1 #ahd ,h>k]1 ,a41 #cj1 #hh ,h>kness1 ,r41 #afa ,h>m]1 ,f4 ,w41 #beh ,h>pes fauna1 #age ,h>rison1 ,w4 ,j41 #acj ,h>tfell %ales1 #afi1 #agj ,ha/+s s&s1 #bcf1 #bcg ,haughton1 ,s41 #bie ,headon b$s1 #bea ,heim1 ,a41 #cb ,hemp/ead b$s1 #bea ,h]cynian sy/ems ( folds1 #bjc ,hicks1 ,h41 #acd1 #ada1 #aec1 #aed1 #afj1 #afa1 #afc1 #afg1 #ahd1 #bff ,hickson1 ,s4 ,j41 #aji ,hill1 ,a41 #bci ,hill1 ,e41 #adb ,hilton %ales1 #baj1 #baa ,h9d1 ,w41 #aif ,h9de1 ,g4 ,j41 #afi1 #aie ,hippurite lime/one1 #bda1 #bdb ,hirnant lime/one1 #afg ,homotaxis1 #dh ,hughes1 ,t4 ,mc,k41 #ada1 #bfd1 #bff ,hull1 ,e41 #abj1 #abb1 #aic1 #bhc ,hume1 ,w4 ,f41 #bci ,hunt1 ,a4 ,r41 #aja ,huronian sy/em1 #adc ,hutton1 ,j41 #bhg ,huxley1 ,t4 ,h41 #ej1 #bej ,igne\s rocks1 #ba-bc ,ilfracombe b$s1 #ahd ,inf]ior oolite1 #bcj ,inv]t$ /rata1 #cb2 detection (1 #cb ,iron age1 #bge1 #bgf ,judd1 ,j4 ,w41 #bci1 #bdg ,jukes1 ,j4 ,b41 #hd ,jukes-,br[ne1 ,a4 ,j41 #abf1 #bci1 #bfd ,jurassic b$s1 #bbe ,jurassic fauna & flora1 #bcd1 #bce ,jurassic sy/em1 #bbf-bce ,kays]1 ,e41 #abe1 #aia ,keewat9 s]ies1 #add ,kelv91 ,"l1 #bhi ,k5dall1 ,p41 #beg ,keup] b$s1 #bah1 #bba1 #bbb ,kid/on1 ,b41 #aii ,kimm]idge clay1 #bcb ,kimm]idgian s]ies1 #bbf ,k+1 ,w41 #bag ,kj]ulf1 ,?41 #hh ,kon9ck1 ,l4 de1 #bja ,kupf]s*ief]1 #bji ,lake1 ,p41 #abf1 #agh ,lam9a1 #bg ,lamplugh1 ,g4 ,w41 #hj1 #aai1 #bfd ,lapwor?1 ,c41 #cb1 #ach1 #aci1 #aef1 #afh-agj1 #agc1 #agh1 #agi ,laur5tian rocks1 #adc ,lawson1 ,a4 ,c41 #add1 #ade ,lehmann1 ,j41 #gg ,l5ham b$s1 #beg ,lewis1 ,h4 ,c41 #bfc ,lias1 #bbf1 #bbi ,liassian s]ies1 #bbg1 #bbi ,l9coln%ire lime/one1 #bcj1 #bca ,l9combe & ,w>b]ry grits1 #ahd ,l9d/rm1 ,g41 #aad ,l+ula flags1 #aeb1 #aee1 #aef ,l9n>sson1 ,j4 ,g4 ,o41 #afa ,ll&eilo lime/one1 #afg ,ll&eilo s]ies1 #afe1 #afg ,ll&ov]y s]ies1 #agd-agg ,loess1 #bfg ,logan1 ,sir ,w41 #bj ,london ,bas91 #bde ,london clay1 #aac1 #bdd1 #bdf ,longmyndian rocks1 #ach ,l[] ,london ,t]ti>y b$s1 #bdd1 #bdf ,lubbock1 ,sir ,j41 #bgj1 #bgg ,ludl[ s]ies1 #agd-agf ,lydekk]1 ,r41 #bej ,lyell1 ,sir ,c41 #f1 #ab1 #ai1 #ajf1 #abi1 #bbd1 #bfc1 #bgj ,lynton slates1 #ahd ,mc,coy1 ,sir ,f41 #bja ,mc,mahon1 ,c4 ,a41 #gg ,mads51 ,h4 ,p41 #bgg ,magnesian ,lime/one1 #bji-baa ,malm1 #bbf ,maps1 geological1 #hd1 #acj2 use (1 #hf1 #abj1 #aba ,m>c\1 ,j41 #acj1 #bgi ,m>9e deposits1 #ajb2 nature ( fossils 91 #ajg ,m>l slate1 #bji1 #baj ,m>l/one1 #bbi ,m>%1 ,o4 ,c41 #bdi ,m>wood b$s1 #ahc ,mat!w1 ,g4 ,f41 #afj-afb1 #ahj ,meadfoot s&s1 #ahd ,me*anically =m$ rocks1 #bi1 #ajb ,mello1 ,j4 ,m41 #bgj ,m5dip sy/em ( folds1 #bjc ,m5evian b$s1 #aeb1 #aed1 #aef1 #afa ,metamorphic rocks1 #be ,miall1 ,l4 ,c41 #abb ,mi*ell1 ,j41 #aj1 #aa ,millepore oolite1 #bcj1 #bca ,mill]1 ,h41 #ahi ,millet se$ s&s1 #ajj ,mill/one grit1 #aib ,mioc5e p]iod1 #beb-bee ,m(fat %ales1 #afi1 #agg ,mojsisovics1 ,e4 von1 #bbd1 #bbg ,morgan1 ,c4 ,ll41 #ada ,morte slates1 #ahd ,moscovian b$s1 #aic1 #cja ,m\nta9 lime/one1 #aib ,mur*ison1 ,sir ,r4 ,i41 #ai1 #bj1 #agd1 #agi ,murray1 ,sir ,j41 #cj ,mus*elkalk1 #bah1 #bba1 #bbb ,nehr+1 ,a41 #bfg1 #bfh ,neobolus fauna1 #afj ,neocomian s]ies1 #bcf-bch ,neoli?ic age1 #bge-bgg ,neumayr1 ,m41 #aae1 #bcc ,newton1 ,e4 ,t41 #de ,ni*olson1 ,h4 ,a41 #ahi1 #bej ,noa*ian ,deluge1 #h ,noetl+1 ,f41 #afj ,nord5skjld1 ,a4 ,e41 #aac1 #aad ,noric b$s1 #bbe ,nor?ampton%ire s&s1 #bcj ,norwi* crag1 #bef1 #beg ,nummulitic lime/one1 #bdh ,old r$ s&/one1 #ahc1 #ahe1 #ahf1 #ahh1 #aia ,oldham1 ,r4 ,d41 #bjh ,oldhav5 b$s1 #bdd1 #bde ,ol5ellus fauna1 #acd1 #aec1 #aef-afj ,ol5us fauna1 #aeb1 #afa1 #afb ,oligoc5e b$s1 #bea1 #beb ,oligoc5e fauna & flora1 #beb ,oolite1 #bbf ,ordovician faunas1 #agb1 #agc ,ordovician sy/em1 #afd-agc ,organically =m$ rocks1 #bi1 #ajb1 #aji ,orog5ic movem5ts1 #cb ,osborne b$s1 #beg ,ow51 ,sir ,r41 #bgg ,ox=d clay1 #bcb ,ox=d oolite1 #bbf ,ox=dian s]ies1 #bbg1 #bcb ,paloli?ic fauna & flora1 #bgj-bgd ,paloli?ic man1 #bfh1 #bgb-bgd ,paloli?ic p]iod1 #bfg-bgd ,palontological break1 #fa ,palo-physiography1 #abj ,p>adoxides fauna1 #aeb1 #afj1 #afa ,peat deposits1 #bge1 #bgf ,pebble b$s ( ,bunt]1 #bah ,pebidian rocks1 #adj ,p5gelly1 ,w41 #bgj ,p5nant /age1 #aib ,p5n9e sy/em ( folds1 #bjc ,p5ri? s&/one1 #ge1 #baj1 #baa ,p]iod1 def9ition (1 #fj ,p]man5ce ( ocean bas9s1 #bgh-bhe ,p]mian fauna & flora1 #bad-baf ,p]mian sy/em1 #bji-bag ,p]mo-c>bonif]\s fauna & flora1 #bjg1 #bjh ,p]mo-c>bonif]\s glacial deposits1 #bjf ,p]mo-c>bonif]\s p]iod1 #bje-bjh ,phillips1 ,j41 #aj1 #aa1 #bja ,physical break1 #fj ,pickwell ,d[n s&/one1 #ahc ,pilton b$s1 #ahc ,plaisancean s]ies1 #bef ,planes ( lam9ation1 #bg ,planes ( /ratification1 #bg ,plei/oc5e fauna & flora1 #bfe1 #bff ,plei/oc5e p]iod1 #bfj-bff ,plioc5e fauna & flora1 #bei ,plioc5e p]iod1 #bef-bei ,portl& oolites1 #bbf ,portl&ian s]ies1 #bbf1 #bcb ,prado1 ,c4 de1 #afa ,precambrian rocks1 #acb2 mode ( =mation (1 #adf ,prell]1 ,c4 ,s4 du ,r41 #bfd ,pre/wi*1 ,sir ,j41 #ai1 #acj1 #bgi ,productus lime/ones1 #bje1 #bjf1 #bad ,protol5us fauna1 #afj ,pseudo-/romatism1 #gf ,purbeckian s]ies1 #bbf1 #bcb ,pyrocla/ic rocks1 #bd ,quad] s&/one1 #bdj ,ramsay1 ,sir ,a4 ,c41 #acj1 #aec1 #afc1 #ahh ,read+ b$s1 #bdd ,recurr5ces1 #bib ,r$ crag1 #bef1 #beg ,reid1 ,c41 #de1 #beg1 #bfd1 #bfh1 #bga ,r5>d1 ,a41 #cj ,rev]s$ fault1 #cd ,rhtic b$s1 #bah ,rhiwlas lime/one1 #afg ,ri*?(51 ,b>on von1 #bfg1 #bfh ,ridley1 ,h4 ,n41 #bga ,riv] drift man1 #bfh ,ro!rham r$ rock1 #bjb ,ro?lieg5de1 #bji ,r\elle1 #ac ,/ ,bees s&/one1 #baj ,/ ,er? b$s1 #beg ,salopian b$s1 #age ,salt]1 ,j4 ,w41 #afa1 #afb1 #ahf ,sc>bro' lime/one1 #bcj1 #bca ,s*i/s1 cry/all9e1 #gf1 #gg1 #acc1 #adg ,scilla1 ,a41 #ac ,screes1 #aja ,scrope1 ,g4 ,p41 #gf ,sections1 geological1 #hd2 use (1 #hh ,s$im5t>y rocks1 #bc ,s$gwick1 ,a41 #af1 #ai1 #bj1 #aec1 #agd ,s5onian s]ies1 #bcf ,s]ies1 def9ition (1 #fj ,sew>d1 ,a4 ,c41 #aac1 #bjh ,sigmoidal /ructure1 #cc ,silice\s rocks1 #bi ,silurian faunas1 #agi1 #ahj ,silurian sy/em1 #agd-ahb ,simulation ( /ructures1 #gb ,s9emurian s]ies1 #bbg1 #bbi ,smi?1 ,w41 #h1 #ab-ah1 #eg1 #he ,soil1 #ajj ,sol5h(5 slate1 #bcd ,sollas1 ,w4 ,j41 #bhh ,solva b$s1 #aeb1 #aed1 #aef1 #afa ,speckl$ s&/one1 #bje1 #bjf ,speeton s]ies1 #bch ,sp5c]1 ,h41 #ej ,spirorbis lime/one1 #bja ,/ages1 def9ition (1 #fj ,/eppe p]iod1 #bfj1 #bfg-bgd ,/onesfield slate1 #bca ,/ra*ey1 ,j41 #aj ,/rahan1 ,a41 #bci1 #bfd ,/rata1 #bg2 classification (1 #eh1 #abe ,/ratification1 #bf ,/ratifi$ rocks1 #bc2 composition (1 #bh2 orig9 (1 #bi2 classification (1 #bh1 #abe2 symbols to repres5t1 #ij ,/ratigraphical geology1 aim (1 #a2 ,w4 ,smi?1 f\nd] (1 #h1 #ab-ah ,suess1 ,e41 #aaj1 #abc1 #bjg1 #bhd ,sup]position1 law (1 #ca ,survey+1 geological1 #hd ,sy/ems1 def9ition (1 #fj ,tal*ir /age1 #bje1 #bjf ,t>annon %ales1 #agd-agg ,teall1 ,j4 ,j4 ,h41 #bhi ,t]re/rial rocks1 #ii ,?anet s&s1 #bdd ,?9n+ out1 #bh ,?ru/ plane1 #cd2 detection (1 #ce1 #hb ,tiddeman1 ,b4 ,h41 #hg1 #bfc1 #bgj ,till1 #bfb ,"t1 geological1 #bid-bif ,to>cian s]ies1 #bbg1 #bbi ,topley1 ,w41 #acj1 #bci ,torridonian b$s1 #ace-acg ,tremadoc slates1 #aeb1 #aee1 #afb1 #afc ,triassic fauna & flora1 #bbc-bbe ,triassic sy/em1 #bah-bbe2 ammonite zones (1 #bbe ,tr9ucleus fauna1 #afe ,tullb]g1 ,s4 ,a41 #afb ,turonian s]ies1 #bcf ,uncon=mity1 #fj1 #gh1 #ih ,und]clays1 #aig ,uni=mit>ianism1 #bhg-bib ,uriconian rocks1 #ach ,us%]1 ,w4 ,a4 ,e41 #ahc ,val5tian b$s1 #age ,v]neuil1 ,e4 ,p4 de1 #afa ,volcanic rocks1 ,cambrian1 #aee2 ,c>bonif]\s1 #aii2 ,devonian1 #ahd1 #ahf2 ,eoc5e1 #bdf1 #bdg2 ,ordovician1 #afe-agj2 ,precambrian1 #adf ,vulcanicity1 #bhi ,waag51 ,w41 #bac1 #bad ,walcott1 ,c4 ,d41 #add1 #aeh1 #afj1 #afa1 #agc ,wallace1 ,a4 ,r41 #abd1 #bce1 #bdj1 #bha1 #bie ,w>d1 ,j4 ,c41 #hg1 #hh1 #bfc1 #bie ,w>m+1 ,e41 #aae ,watts1 ,w4 ,w41 #adb1 #afh1 #agh ,weald5 b$s1 #bcf1 #bcg ,web/]1 ,t41 #ah ,weisslieg5de1 #bad ,w5lock lime/one1 #age1 #agf ,w5lock s]ies1 #agd-agg ,w5lock %ale1 #age-agg ,w]f5] ,s*i*t51 #bbe ,w]n]1 ,a4 ,g41 #ab ,weyb\rne crag1 #bef ,:ewell1 ,w41 #ej ,:idb\rne1 ,g4 ,f41 #ia ,:ite ,jura1 #bbf ,:itehav5 s&/one1 #bjb ,:itehur/1 ,j41 #aa1 #ab ,wiman1 ,c41 #df ,wood1 ,s4 ,v41 #bej1 #bei ,woodw>d1 ,h41 #aia ,woodw>d1 ,h4 ,b41 #fh1 #acj1 #aca ,woodw>d1 ,j41 #h-aj ,woodw>d1 ,s4 ,p41 #ajh1 #aaa ,woolhope lime/one1 #age ,woolwi* b$s1 #bdd ,wright1 ,g4 ,f41 #bfc ,yor$ale s]ies1 #aib ,zanclean s]ies1 #bef ,ze*/e91 #bji ,zone1 fossil1 #fg2 ammonite1 #bbe1 #bcg2 graptolite1 #fi ,,cambridge3 ,,pr9t$ ,,by ,j4 ,,& ,c4 ,f4 ,,clay1 ,,at ,,! ,,univ]sity ,,press4 ,cambridge ,natural ,sci5ce ,manuals4 ,,biological ,,s]ies4 ,g5]al ,editor1 ,a4 ,e4 ,%ipley1 ,m4,a4 ,elem5t>y ,palontology--,inv]tebrate ,h4 ,woods1 ,m4,a41 ,f4,g4,s4 #fs4 ,elem5ts ( ,botany ,f4 ,d>w91 ,m4,a41 ,f4,r4,s4 #ds4 #f;d4 ,practical ,physiology ( ,plants ,f4 ,d>w91 ,e4 ,h4 ,acton1 ,m4,a4 #ds4 #f;d4 ,practical ,morbid ,anatomy ,h4 ,d4 ,rolle/on1 ,m4,d41 ,f4,r4,c4,p4 ,a4 ,a4 ,kan?ack1 ,m4,d41 ,m4,r4,c4,p4 #fs4 ,zoogeography ,f4 ,e4 ,b$d>d1 ,m4,a41 ,f4,r4,s4 #fs4 ,fl[]+-,plants & ,f]ns ,j4 ,c4 ,willis1 ,m4,a4 ,9 two vols4 #ajs4 #f;d4 ,! ,v]tebrate ,skeleton ,s4 ,h4 ,reynolds1 ,m4,a4 #abs4 #f;d4 ,fossil ,plants ,a4 ,c4 ,sew>d1 ,m4,a41 ,f4,g4,s4 #b vols4 ,vol4 ,i4 #abs4 ,outl9es ( ,v]tebrate ,palontology ,a4 ,s4 ,woodw>d4 #ads4 ,! ,soluble ,f]m5ts & ,f]m5tation ,j4 ,reynolds ,gre51 ,sc4,d41 ,f4,r4,s4 #abs4 ,zoology ,e4 ,w4 ,mac,bride1 ,m4,a4 & ,a4 ,e4 ,%ipley1 ,m4,a4 ,9 ! ,press4 ,,physical ,,s]ies4 ,g5]al ,editor1 ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s4 ,heat & ,light ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s4 #es4 9 two sep>ate p>ts ea* #cs4 ,me*anics & ,hydro/atics ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s4 #hs4 #f;d4 9 ?ree sep>ate p>ts ,"p ,i4 ,dynamics #ds4 ,,ii4 ,/atics #cs4 ,,iii4 ,hydro/atics #cs4 ,solution & ,electrolysis ,w4 ,c4 ,d4 ,:e?am1 ,m4,a4 #gs4 #f;d4 ,out ( pr9t4 ,electricity & ,magnetism ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s4 ,9 ,prep>ation4 ,,geological ,,s]ies4 ,petrology = ,/ud5ts ,a4 ,h>k]1 ,m4,a41 ,f4,g4,s4 #gs4 #f;d4 ,h&book to ! ,geology ( ,cambs ,f4 ,r4 ,c4 ,re$1 ,m4,a4 #gs4 #f;d4 ,! ,pr9ciples ( ,/ratigraphical ,geology ,j4 ,e4 ,m>r1 ,m4,a4 #fs4 ,cry/allography ,pr(4 ,w4 ,j4 ,lewis1 ,m4,a4 #ads4 ,net4 99 99 99 99 99 ,laboratory ,note-,books ( ,l4 ,r4 ,wilb]=ce1 ,m4,a41 & ,elem5t>y ,physics ,t4 ,c4 ,fitzpatrick1 ,m4,a4 ,i4 ,me*anics & ,hydro/atics4 ,,ii4 ,heat & ,optics4 ,,iii4 ,electricity & ,magnetism4 ea* #as4 ,o!r volumes are 9 prep>ation & w be ann\nc$ %ortly4 ,press ,op9ions4 ,,biological ,,s]ies4 ,a ,manual & ,diction>y ( ! ,fl[]+ ,plants & ,f]ns4 ,morphology1 ,natural ,hi/ory & ,classification4 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"q4 ,8 /yle1 :ile nev] lack+ dignity1 avoids ! dulness :i* too (t5 accompanies t virtue4 ,elem5t>y ,palontology--,inv]tebrate4 ,by ,h5ry ,woods1 ,m4,a41 ,f4,g4,s4 ,) ,illu/rations4 ,cr[n #hvo4 ,second ,edition4 #fs4 ,nature4 ,z an introduction to ! /udy ( palontology ,mr ,woods's book is wor?y ( high praise4 ,outl9es ( ,v]tebrate ,palontology = ! use ( ,/ud5ts ( ,zoology4 ,by ,a4 ,s4 ,woodw>d1 ,assi/ant ,keep] 9 ! ,dep>tm5t ( ,geology 9 ! ,briti% ,museum4 ,demy #hvo4 #ads4 ,a!num4 ,mr ,woodw>d1 9 /udy+ v]tebrate fossils = ! purpose ( ?is volume1 takes ! biological view1 & has design$ 8 "w prim>ily = ! assi/ance ( /ud5ts ( v]tebrate morphology & zoology4 ,m9dful1 h[ev]1 ( ! geological side ( ! subject1 he has introduc$ a *apt] on ! succession ( ! v]tebrate faunas1 (f]+ a brief b conv5i5t summ>y ( ! di/ribution ( v]tebrate life ?r\gh\t geologic "t4 ,! au?or is to be congratulat$ on hav+ produc$ a "w ( exceptional value1 deal+ ) a difficult subject 9 a ?or\ghly s\nd mann]4 ,! ,v]tebrate ,skeleton4 ,by ,s4 ,h4 ,reynolds1 ,m4,a41 ,tr9ity ,college4 ,cr[n #hvo4 #abs4 #f;d4 ,briti% ,m$ical ,j\rnal4 ,a volume :i* w c]ta9ly take its place among/ ! /&>d text-books ( ! day4 ,,biological ,,s]ies4 ,practical ,morbid ,anatomy4 ,by ,h4 ,d4 ,rolle/on1 ,m4,d41 ,f4,r4,c4,p41 ,fell[ ( ,/ ,john's ,college1 ,cambridge1 ,assi/ant ,physician & ,lectur] on ,pa?ology1 ,/ ,george's ,hospital1 ,london1 & ,a4 ,a4 ,kan?ack1 ,m4,d41 ,m4,r4,c4,p41 ,lectur] on ,pa?ology1 ,/ ,b>?olomew's ,hospital1 ,london4 ,cr[n #hvo4 #fs4 ,briti% ,m$ical ,j\rnal4 ,?is manual c 9 e s5se be mo/ highly recomm5d$1 & x %\ld supply :at has hi!rto be5 a real want4 ,! ,soluble ,f]m5ts & ,f]m5tation4 ,by ,j4 ,reynolds ,gre51 ,sc4,d41 ,f4,r4,s41 ,pr(essor ( ,botany to ! ,ph>maceutical ,society ( ,great ,brita94 ,demy #hvo4 #abs4 ,nature4 ,x is n necess>y to recomm5d ! p]usal ( ! book1 to all int]e/$ 9 ! subject s9ce x is indisp5sable to !m1 & we w m]ely conclude by congratulat+ ! ,cambridge ,univ]sity ,press on hav+ add$ to _! admirable s]ies ( ,natural ,sci5ce ,manuals an em95tly successful "w on s important & difficult a !me1 & ! au?or on hav+ writt5 a treatise clev]ly conceiv$1 indu/ri\sly & ably work$ out1 & on ! :ole1 well writt54 ,brew]'s ,j\rnal4 ,x w ( c\rse f9d a place 9 e brew]'s libr>y1 & w be a "w mu* /udi$ & mu* pond]$ ov] by ! ?\ghtful & highly tra9$ m5 :o n[ repres5t our pr(ession4 ,,physical ,,s]ies4 ,me*anics & ,hydro/atics4 ,an ,elem5t>y ,text-book1 ,!oretical & ,practical1 = ,colleges & ,s*ools4 ,by ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s41 ,fell[ ( ,tr9ity ,college1 ,cambridge1 ,director ( ! ,national ,physical ,laboratory4 ,) ,illu/rations4 ,cr[n #hvo4 #hs4 #f;d4 ,also 9 sep>ate p>ts4 ,"p ,i4 ,dynamics4 #ds4 ,"p ,,ii4 ,/atics4 #cs4 ,"p ,,iii4 ,hydro/atics4 #cs4 ,k4 ,we cordially recomm5d ,mr ,glazebrook's volumes to ! notice ( tea*]s4 ,practical ,tea*]4 ,we he>tily recomm5d ^! books to ! notice ( all sci5ce tea*]s1 & especially to ! ma/]s ( ,organis$ ,sci5ce ,s*ools1 :i* w soon h to face ! "q ( simple practical "w 9 physics1 = :i* ^! books w con/itute an admirable introduction if n a complete vade mecum4 ,heat & ,light4 ,an ,elem5t>y ,text-book1 ,!oretical & ,practical1 = ,colleges & ,s*ools4 ,by ,r4 ,t4 ,glazebrook1 ,m4,a41 ,f4,r4,s4 ,cr[n #hvo4 #es4 ,! two p>ts are also publi%$ sep>ately4 ,heat4 #cs4 ,light4 #cs4 ,j\rnal ( ,education4 ,we h no hesitation 9 recomm5d+ ?is book to ! notice ( tea*]s4 ,practical ,photograph]4 ,mr ,glazebrook's text-book on ,light _c be too highly recomm5d$4 ,,geological ,,s]ies4 ,h&book to ! ,geology ( ,cambridge%ire4 ,= ! use ( ,/ud5ts4 ,by ,f4 ,r4 ,c[p] ,re$1 ,m4,a41 ,f4,g4,s41 ,assi/ant to ! ,woodw>dian ,pr(essor ( ,geology4 ,) ,illu/rations4 ,cr[n #hvo4 #gs4 #f;d4 ,nature4 ,! geology ( ,cambridge%ire possesses a special int]e/ = _m /ud5ts4444 ,!re is mu* 9 ,cambridge%ire geology to ar\se int]e/ :5 once an en?usiasm = ! sci5ce has be5 k9dl$1 & !re 0 ne$ ( a concise h&-book :i* %\ld cle>ly describe & expla9 ! lead+ facts t h be5 made kn[n4444 ,! pres5t "w is a model ( :at a c\nty geology %\ld be4 ,! ,pr9ciples ( ,/ratigraphical ,geology4 ,by ,j4 ,e4 ,m>r1 ,m4,a41 ,fell[ ( ,/ ,john's ,college1 ,cambridge4 ,cr[n #hvo4 #fs4 ,nature4 ,! "w w prove exce$+ly useful to ! advanc$ /ud5t2 x is full ( h9ts & ref]5ces1 ga!r$ dur+ ! au?or's long exp]i5ce z a tea*] & obs]v]1 & :i* w be valuable to all :o seek to int]pret ! hi/ory ( our /ratifi$ =mations4 ,univ]sity ,ext5sion ,j\rnal4 ,mr ,m>r is an old ,univ]sity ,ext5sion lectur]1 & 8 book1 :i* is di/+ui%$ by ! lucidity & ?or\ghness :i* *>act]ise all 8 "w1 _c fail to be ( s]vice to ,univ]sity ,ext5sion /ud5ts :o are mak+ a s]i\s /udy ( ,geology4 ,cry/allography4 ,by ,w4 ,j4 ,lewis1 ,m4,a41 ,pr(essor ( ,m9]alogy 9 ! ,univ]sity ( ,cambridge4 ,demy #hvo4 #ads4 net4 ,a!num4 ,pr(4 ,lewis has writt5 a valuable "w4444 ,! pres5t "w des]ves to be welcom$ n only z a greatly ne$$ help to advanc$ /ud5ts ( m9]alogy1 b z a sign t ! /udy itself ma9ta9s an hon\r$ place 9 ! univ]sity ,sci5ce ,c\rse4 ,nature4 ,! au?or & ! ,univ]sity ,press may be congratulat$ on ! completion ( a treatise wor?y ( ! subject & ( ! ,univ]sity4 ,petrology = ,/ud5ts4 ,an ,introduction to ! ,/udy ( ,rocks "u ! ,microscope4 ,by ,a4 ,h>k]1 ,m4,a41 ,f4,g4,s41 ,fell[ ( ,/ ,john's ,college1 & ,demon/rator 9 ,geology 7,petrology7 9 ! ,univ]sity ( ,cambridge4 ,cr[n #hvo4 ,second ,edition1 ,revis$4 #gs4 #f;d4 ,nature4 ,no bett] introduction to ! /udy ( petrology c\ld be desir$ ?an is af=d$ by ,mr ,h>k]'s volume4 ,london3 ,c4 ,j4 ,,clay ,,& ,,sons1 ,,cambridge ,,univ]sity ,,press ,,w>eh\se1 ,,ave ,,m>ia ,,lane ,,& ,h4 ,k4 ,,lewis1 #acf1 ,,g[] ,,/reet1 ,w4,c4 ,m$ical ,publi%] & ,booksell]4 ,transcrib]'s ,note ,any obsolete or alt]nate spell+ & gramm> 0 reta9$4 ,all obvi\s typographical errors 7 correct$4 ,al?\gh hyph5ation ( words has be5 /&>diz$ to ! mo/ preval5t occurr5ce1 ! six occurr5ces ( fre%-wat] 7 n conv]t$ to fre%wat] 7#cj occurr5ces7 due to usage4 ,correct$ spell+s3 ,godw9-,au/5 7p4 #bj72 ,:idb\rne 7p4 #aia72 & ,i*?yopt]ygia 7p4 #bbc74