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Ck ih Riad hie ban} Pied Re ees al i: Whe mh wh bald «hy ap ‘ . wae: ¢ vesendon : 4 enqeq ard ‘ int oe a bey Vee Le UR NETH DE jedty dying +h fi Abst pt “ vow ' ‘ é . ' Wied yoiaaay git tie Isytaiot ogy ay iY Taig rath ' | \ a - ar ! 4 roarqed 6 Te MALL a tts See ha Be okt ioe ‘ ‘ a ‘ ' Sr ee ee | = oH 1 ' =< venaset (9) smupngr woe t al * ney 1 0m . ‘ ides Laetes heme ‘ ‘ A peMe TT CO NTNR ele a ’ ' t@ 1 ‘ ‘ ' eee ee) 0? f Wh ” welll ' a 4 Oty ‘nt me , ato < toned fanedront a aaa , eres Viteed she ssyiuee ye . ae ‘ ‘ Gr bet hy pee ey whde itdegel ures) | Mette edad | "isles ia ‘ eae Vettes ee en Sa i vig ye neg een gee 1 idep dornree an ibe young site ' ' + ‘ toa ' wr 4 ( er Le ee DE Le ee onew wg ygey bo} ud aty Pt] wen ie, sage ne ay ~~ Ting. poe teee tows y . ‘ 4 9%trfeea fy owt peta HOA yt anh. ee, nary daese sue4 4 . ‘ ‘ mie " ‘ . COVUL Deter i Lien ne ae RL Re UEC rf ype 734 . habe AP i erlbe oun pede enknt - ‘ . yee let wey mes ’ born vden rege eo ome bpd ed ep 6 ‘ . “ee oats nae ’ ‘ ay abe ont , ‘ . ' ; 1 ovus ena yew yur hejeu doav “ cas > r te be val ‘s mh aes a Le “es . / y 7) ‘ 1 te ' te ’ weqen etter sy wry . eae ee Ue a et ’ Ho ; ‘ a ee ethan ew ms run Rea WT * eu nyt vee bbl sare pigate ds rerves Pinney 4 s . inn ‘ vw vy gete® +e veMryee ww ge de bye ms , yee ivi 4 it WIE pgp eines a” it ur . y a : ‘ ow s o $y otty aie std uae ' nem ey videgrieneve orn =~ - rors ot yo ne et tee? faery $4 kG Me) Oe ee ’ denn Sawn semae® y eee " a otha iw ” Gov sieaaneees ain th ie Z 4 a « ~ ~ 2 ~S % * oe - - : _ 4 - z a — . - he Es - ~ Z ~ : * ee 2, Sr - - e ~~ a _ Fe “ ~? Mean 4 ee “ » lo S iy ‘5 Pi Wa? Doe Wd eae Pee aaa ee wae r BULLETIN. EROLOGICAL, SOCIETY /7 ALM BITC VOL. 34 JOSEPH STANLEY-BROWN, Editor f JAN 16 1924. ) 2, BOF O BRS / NEW YORK PUBLISHED BY THE SOCIETY 1923 OFFICERS FOR 1923 Davin Wuite, President Wittram H: Hopsss, Wituiam H. Emmons, Vice-Presidents T. WAYLAND VAUGHAN, Epear T. WHERRY, CHARLES P. Berkey, Secretary Epwarp B. MatHews, T'reasurer JOSEPH STANLEY-Brown, Fditor Class of 1925 EpmunpD OTs Hovey, ALFRED H. Brooks, Class of 1924 K. 8. Bastin, Councilors L. G. WEsTGATE, Class of 1923 L. C. GRATON, G. D. LOoUDERBACK. PRINTERS JUDD & DETWEILER (INC.), WASHINGTON, D. C. ENGRAVERS THE MAURICE JOYCE ENGRAVING COMPANY, WASHINGTON, D. C. CONTENTS Page Proceedings of the Thirty-fifth Annual Meeting of the Geological Society of America, held at Ann Arbor, Michigan, Thursday-Saturday, Decem- esa, 1922 > CHARLES P. BERKEY, Sccretary..........0000cecanceue 1 Zener Phursday morning, December 28.......6..3...ccdacceeecce 5 eater AE MC OUITRCT 28. yc 5 Soo enw Ss edd ccs Sin Pee oo ee 6 ee ee tN SAC INORG @ ‘shia! a: ce + ao 0. #! 3 cas ela ee OO My eal 6 IS EEST SISOS IE) TO eee AO, oe tee ey a IRC hs ed 9 aeRO te ios 5 5's a lara Clo ob} oie ee SS Ae RES ae eevee 10 Peeion ot Auditing Committee... . 0.00. .260. 00.0 ee ens aE a 11 Election of officers, members of standing committees, and Fellows 12 Vote on proposed amendment to the Constitution............... 13 Introduction of Correspondent Emmanuel de Margerie.......... 14 Report of the representative to the International Geological Con- eee Ee oe ai ald wat vce be sale oben a ee 14 meport of Committee on Teaching Geology...................-- 14 SEE B00 1130 a fo is. cy wie Sis 60,0 lL wiale ook oe ce te ete Calls adeeb tena Bie 15 Memorial of Guy H. Cox (with bibliography) ; by C. L. Dake 15 Memorial of Joseph Barrell (with bibliography); by Her- Rete OE MI Nc OES TY 02) OE ves aii Ns ahs’ ws aie ls wana es boas, oebwrs Ge wae Cea 18 The work of Joseph Barrell on problems in sedimentation; PEOAVAS. VAYLAND YAUGHAN 25.2055 a00s cee oe ee dees 28 Memorial of James E. Todd (with bibliography) ; by FranK “LE IRD ats ee nia leah Cae aS Senet 44 Memorial of Levi Holbrook; by JAMES F. KEmMP............ 51 peewee the £eEtirine President. .. iis... ..0 css ce kee wees es 574 mnenESO AY QLLCTNOON... 00... eee cece te cece eee wcccceees 53 PERMITS: PECSONLEO . os. cee ccc etc ewes eden enc enewnes 53 Symposium on the structure and history of mountains and the er ER AICTT “CEVClOPIBENL. os oc ce bc. cei s oe es wee cele ap eee 53 Sites and nature of the North American geosynclines; Presi- dential address by CHARLES SCHUCHERT........-...--000- 53 The theory of mountain structure recently set forth by Pro- fessor Kober of Vienna; by CHESTER R. LONGWELL........ 53 ee eines by, WILLIAM HH. ELOBBS. 0... ed eee ee cee ee 53 Peep aaenians: by ARTHUR, KITE 2 2j.jc50 ce 2 cee ee es D3 Hastern Appalachians in the latitude of southern New Eng- ene atel cis.) VV OODW ORE 2 Sc 0s case's cide tne 8 awe ee ee ae Coast Ranges and Sierra Nevadas; by BamLey WILLIS....... 733 Rocky Mountains of Idaho and Montana; by G. R. MANSFIELD 55 Front ranges of Colorado and New Mexico; by Wixtis T. LEE 454 TES FITESTS TEs gle a 20 a 6 fae 54 Division of Geology and Geography, National Research Council... 54 IE SER aS a rae ogc. Oh Ee ueialnoah Sets is Jo) din, 3, 0,0 Hig ace ds ¢ 0 ele 54 Session of Friday morning, JECT 17s Sees NP on ee ee 55 Semmenortof the Auditing Committee..............-....2..e eens DD Memewort on securities..................- eee Phe ae fe a 56 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page Titles and abstracts of papers and discussions thereon, presented before ‘the: MOEMING: SESSION w.Kk oo rik ees Pee ae ee eee 56 Recent work in France and Switzerland on the structure of the Alps; by EMMANUEL DE MARGERIN.. 3). 0....<¢-.--5- 56 A layman’s view of the theory of isostasy [abstract and dis- cussion]; by $C... Ko LEPritts dene ee ee 57 Rectilinear shorelines of the New England-Acadian region [abstract]; by DovceLas. W. JOHNSON .42. 2.2)... eee 57 Dynamics of faulting and folding [abstract]; by Harry HTELDING (RUEDD Eo ib. Siac o oled ne 0k Pero ee nee oe ‘2 2S Criteria for the recognition of active faults; by STEPHEN IPABOR ees oes oe onc OS 3s a are Le eee 58 Fault map of California [abstract]; by BAILEY WILLIs..... 58 Faults of the Coast Ranges of California [abstract and dis- cussion]: ‘by BAmEY WiaEEdAS © .3... 25025 2.003 405 ee 58 Late Tertiary and Quaternary diastrophism in southern Cebu, Philippine Islands [abstract]; by GrorcE D. LOUDERBACK and™® By. SRS MORSE. op tone ase Sites oh oe Borsa Se ee 59 Parallel folds and boudinage [abstract]; by 'TERENcE T. CUT RS coin! Bein aves 8 ead Civica eet Maa. eats, oe Fated eae Shee een 59 Group photograph. ss se ews oe Ss oii ohh oie ie iste te re 60 Luncheon viven by the. University. 6.02% <5 aves os ae eee 60 Sessions. of Friday afternoon . 22. ..< 2.5. sie ..4 2 stale po eee, ce 60 Sectional meeting of Friday afternoon for Group A............. 60 Titles and abstracts of papers of Group A and discussions thereon 61 Contributions to the hypothesis of mountain formation; by B.. Gs ANDREWS: ooo cle oS bao Sind sR wees eee we noe Se 61 Earth’s crust and its evolution [abstract and discussion]; by Ry Aco Day 3 ete eae we ee ee ee 61 Orogenic exigencies of a rotary earth [abstract] ; by CHARLES Fey SRR. Bai vae ee Seis © tala e mt eha arate ete hie eae eee wis ate ee 62 lsostasy as a result of earth shrinkage [abstract]; by FRAN- CIS PARKER, SHEPARD. 2.) 6 .csies,c wwe oleae ea o's bape ae 62 Fissility of shale: Some factors concerned in its development [abstract]; by J. VOLNEY LEWIS... 2.00 5.% sens. > epee 63 Development of shrinkage cracks in sediments without ex- posure to the atmosphere [abstract]; by W.H.TwWENHOFEL 64 Observations on the range and distribution of certain types of Canadian Pleistocene concretions [abstract and discus- sion]; by EDWAED M. KRINDLE. | ou. <0. Mies pens oe eee 64 Boom Beach (Isle-au-Haut, Maine), a sea-mill [abstract and discussion] > “by Jomn M.: CLABES. 2..0/05.. 6.5. eee 65 Crystalline rocks of the Plains; by CHARLES N. GOULD...... 66 Precambrian folding in North America; by WILLIAM J. | WU Tra. 5 6 eC ees ne, es ce te Si ah nea vite 0 ore 66 Notes on the salt domes of North America [abstract]; by E. Dye Gone rs i eis ee hl ow ce Remi eles ote oie oe 0-8 ose cgele en 66 Some structural features of northern Idaho [abstract]; by doserr Bie WMPLEBT. 65 She ow eso diets os ore ev es Ws oe 66 CONTENTS Data on the geographic nomenclature of the southern Cali- fornia and Texas regions [abstract]; by Roserr T. HILL... Sectional meeting of Friday afternoon for Group B......... Be Titles and abstracts of papers of Group B and discussions thereon Successful method of teaching historical geology [abstract] ; Dye aHORe rn bla WO ROAD WIECH so. . cia eae eethe ae ee oe take eos Ordovician overlap in the Piedmont of southern Pennsylva- nia and Maryland; by GrEorGE W. StTosE and ANNA I. JoNAS Chemung stratigraphy in western New York [abstract]; by AGG Hive el oye MEANY WUPEOUKC te, Se) bee vw ars aive ‘olden canis Cuaiee aren Ree ae bagasse 8 Correlation of the Pottsville and Lower Allegheny formations in western Pennsylvania [abstract and discussion]; by B. AG OIE EPIC AUN ee ENINGI@ Were aes s Tahoe Si at bila’ oi'e vale canton ctw wile cc daekers, secels Structural study of a part of northeast Texas, with some stratigraphic sections [abstract]; by F. Junius Fous and EEPAREDG IVI SEVORMINISO ING ty. a ec id: eb /e c's ab osc. sbavenkl elsig seibi nye ele ile iene The lance problem [abstract]; by FREEMAN WaArRD.......... Observations on coal ‘swamps in northern West Virginia where. Permian conditions prevail [abstract]; by JouHn L. “SEATON ye ee SR Se le Pe LA er -Further contributions to the knowledge of the Cretaceous of Texas and northern Mexico [abstract]; by RosBrert T. Hit. Paleozoic rocks found in deep wells in Wisconsin and north- ern lino lapstraeh|; by EB. 'T. TH WAITHS. 0.20... ee ee Merging of the Carlile shale and Timpas limestone forma- tions in southeastern Colorado; by H. B. PATTon......... Present status of the geodetic work in the United States and its value to geology [abstract]; by WILLIAM BowIE....... Reconnaissance traverse from Mojave Ulojane, California, to Rock Creek, Utah [abstract]; by Hrersert HE. GREGORY.... Topography and geology of the Okanogan Highlands and Co- lumbia Plateau of Washington [abstract]; by SoLon SHEDD Tertiary stratigraphy in the lower Rio Grande region [ab- SiraGhigeDy CARTED (Ch AP ROWBBIDGE «02.0.6 2 ob. ale oe as © oe MITA SOMO. «cle se he a oale PR ire Seale ten Oi ig ce ha Niele ilene Glevahe Reece S sO TORCION SOCICEIES asics. ec eso weal elaatglss see ede a ce Resolutions of appreciation to H. O. Hovey, retiring Secretary... emia Wy UMN Otise LLOVEGYe. Fics. cow. sve lk ee ee ule ec wee wae ee Session Ok Saturday mornings, December 80..... 0.0. .6.. ccc cee ne ewan Titles and abstracts of papers and discussions thereon, presented HERO NC MOL MIMS SCSSIOME IL 2 wcll W cals ck a fe sle wesc ceca sescae Geological reconnaissance in Mongolia [abstract and discus- STON Cry Sia Wau TOS | Bs 55101 Re ON a Problem of mild geological climates [abstract]; by EL.s- iN Ee Aa aE ENED IG MGDINGG cia Sociale Cae lie wel Blew ejblele eiatece se pie wtein eave Further experiments on the fracturing of hollow brittle spheres and their bearing on major diastrophism [abstract Aid CISGUSSION |; by WALTER Hi. BUCHER. 2. ..\o. wines Owe 68 68 81 vl BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page Some structural features of the plains area of Alberta caused by Pleistocene glaciation; by OLIvER B. HopPKINS..:...... 82 Correspondence between the Gondwana system of Hindustan and the Newark system of the eastern United States [ab- stract and discussion]; by WILLIAM H. Hopss............ 82 Quantitative criteria in paleogeography [abstract and discus- sion]; by “RAYMOND °G. MOORE; J.2<. snes oe Oe ee eee $5 Keweenaw geothermal gradients and the ice age [abstract] ; by ALFRED: G. TUANE sc. 23°)... ya Ss Ee eee 86 Votes of ‘thanks: oo. peste ks on WE ORE aK Seeks ee 87 Titles and abstracts of papers of Group A and discussions thereon 87 Physical history of the Colorado Front Range [abstract]; by F. M. Van Tuy. and G. W. MACHAMER..< =... .20:.< eee ST Structural features of the Colorado Plateau and their origin; by RAYMOND: CG; MOORE... )o5 8620 6S SoS See ee 88 Structure of the Spring Mountain Range, southern Nevada fabstract]; by Do. ERBWEPt. . oes. ces oo eee 89 Pleistocene of northwestern Illinois: a graphic presentation of some of the chief lines of evidence [abstract]; by Mor- BIS M. LEIGHTON. 2s oie. oe eee es oa eb ee ee 90 Fossiliferous loess*beneath tilted Galena dolomite at the bor- der of the Belvidere lobe, in northwestern Illinois [ab- stract]; by Morris M:. LeIGHTon:..:..<. o.>. 26 eee 90 Late Tertiary and Pleistocene terrace plains of the middle Atlantic Coastal Plain [abstract]; by CHESTER K. WENT- WORDED. filo Fa bee ei ae ne tn ee ee 91 Glacial deposits of Missouri and adjacent districts [ab- stract];“by FRANK ULEVERETT ) 2% . 00.6 e's ek 2 91 Glacial drainage on the Columbia Plateau of Washington; by J.’ Hagten>” Bemis fos bo ks Ae ee 92 Glacial lake problems [abstract]; by GEorGE H. CHADWICK.. 92 Tce action on inland lakes [abstract]; by Irvine D. Scorr... 92 Banded postglacial clay near New York City [abstract]; by @ursrum Az. “REEDS oe yo Gs SAE ol ee ee 92 Origin and history of extinct Lake Calvin, Iowa [abstract]; by Water H.. SoHOEWEL. so. ss 2600-2 kN 93 Physiography of the Paria River valley, southern Utah [ab- stract]; by RAYMOND: GC. MOORE... : \. on: 33. 25 94 Sand rivers of Texas and California and some of their ac- companying phenomena [abstract]; by Ropert T. HILL.... 95 Sedimentation at the mouths of the Mississippi River—pre- liminary report [abstract]; by ARTHUR C. TROWBRIDGE.... 95 Geological map of the Bushveld complex, Transvaal, South Africa [abstract]; by Cuargius PALACHE.....:-.2 ogee 95 Titles and abstracts of papers of Group C and discussions thereon 96 Metamorphism of quartzites by the Bushveld igneous com- plex [abstract]; by’ Frep, BE. WRIGHT...) ... 5... eee 96 Fusion of sedimentary rocks in drill-holes [abstract]; by BAtIEY “WIS oi) or CRRA SES cae bs ce ee 96 CONTENTS Vil Page Fusion of sedimentary rocks in drill-holes; by N. L. Bowen DIE Vhs f- ATU OI SSRATIN Betty. cue hel dane S akcmetee renee bay ane Cle ds Ws dns 96 Xenoliths in the Stony Creek, Connecticut, granite [discus- SOU GEA eel ORR Pee cl DG ede a eae rts BCA aa 96 New teaching diagram for igneous rocks; by A. B. Van TDS EUEXO) B00 ener gen chet Bahn reek Aloe cae RR gune hs rc! rT Ok VP Stn eo OF, Aerolite from Rose City, ACMI [abstract]; by EpmuNnpb A) TUS eg TEL OWEN Beet Matrat such ie pothnsivtom bene See Suda e SATAD eed ec Gow lees kc TG Origin and formation of certain Appalachian bauxite de- DOSIESE IDiy, c\CLIEBU B PAS INET SO Nematic cakes Sits Shela ee claus aly oslo: Siri Stormberg lavas of South Africa [abstract and discussion] ; Age eee NWR E sa Rhee te PA bt enw cee ola dee header eagke oie Dia tae 97 A high temperature vein in Madison County, Missouri [ab- Seer ra (Wa NNER DAR au ete 3 chaps, Be GRia al ae iets Mel ave eC SIS. Cretaceous age and early Eocene uplift of a peneplain in the southern interior of British Columbia and the development of the north Thompson River trench; by W. L. Uctow.... 99 Study of the igneous rocks of Ithaca, New York, and vicinity abst Each) . eis sees nae ee ee 243 Cross-section of the Appalachians in southern New England; by J. B. WO0UWORTH 5. fas or oF oS Bae Oe ence ee ; 2538 Structure of the Rocky Mountains in Idaho and Montana; by G. R. Nicaea BIELD. oP FoR is ke SESE ONS ee Sta SRE oo Deere eee ne ¥, See Building of the southern Rocky Mountains, by Wiiiis T. LEE; with Notes. on isostasy, by C. E. VAN ORSTRAND, and Elastic yielding of the earth’s crust under a load of sedimentary deposits, by W. D. LAMBERT........ . 285 Outlines of Appalachian structure; by ARTHUR KEITH ......0... 52% -. cee 309 Contribution to the hypothesis of mountain formation; by E. C. ANDREWS 381 Recent aes and trends in vertebrate paleontology; Presidential ad- ~- dress: by We D2 MarTTenw 2 asd in SPOS oe OS ke See 2 are ee 401 Some structural eee of the plains area of Alberta caused by Pleisto- cene slaciation = hy-O: By TROP RAN ST. 39s 2. SU tek ee ee 419 Fusion of sedimentary rocks in drill-holes; by N. L. BoWkrn and M. A GBOUSSHAU AT SG er Re wie ease aed Sood rege Ree eerie Rc ene ee 431 Carnivorous Saurischia in Europe since the Triassic; by F. von HuENE.. 449 Contribution to the yomer-parasphenoid question; by F. von HUENE..... 459 Lines of phyletic and biological development of the Ichthyopterygia; by By. VON ELUBNG 5 ioe Sceic Paro SO SaaS ee ee ROS UNG ke Ue RO mne ete eee eee ae 463 Is the channel of the Missouri River through North Dakota of Tertiary origin 75 Dy. dt B- BODD 655 a ist HA Ie Oia eres Cave Sires a as eee .. 469 Merging of Carlile shale and Timpas. limestone formations in southeastern Golorade: by? Hi. BU PaPrroni ee . OaAG Se ee eee ee eee ADD Glacialdake problems; by G. H. CHADWICK J. 3i7. 2250 .4%. 5 Sa eel ee 499 Ordovician overlap in the Piedmont province of Pennsylvania and Mary- land: by-G. W. Srose and Anwa $l: JONAS, . 2. cs<. 00s 0 eae ee 5OT Appalachian bauxite deposits; by W. A. NELSON:.......0........é.u5eum 525 Crystalline rocks of the Plains; by C. N» GOULD. :..... 003205. 2) 2 ope 541 Cretaceous age and early Eocene uplift of a peneplain in southern British Columbia’; by W. LL. UGiow . ois o3.coe cs Ses Fo PE eee 561 Glaciation drainage on the Columbia Plateau; by J. Hy) Berti cp 573 Range and distribution of certain types of Canadian Pleistocene concre- tions + by-E. M. Kanpimens: sv etow 9s yo le wee ee ee ee eee 609 3oudinage, an unusual structural phenomenon; by T. T. QUIRKE......... 649 Some criteria used in recognizing active faults; by STEPHEN TABER...... 661 The Lake Superior geosyncline; by W. O. HOTCHKISS..............-08:- 669 Pre-Cambrian folding in North America; by W. J. MIULLmR............... 679 Geotherms of Lake Superior copper country; by A. C. LANE............. 7038 Cambro-Ordovician section near Mount Robson, British Columbia; by L: D. BURLING. ou8 Fer a cake Dae So Sle oa ote Se Le eee ee 721 ILLUSTRATIONS X1 : ILLUSTRATIONS PLATES Page ne tant sPorirait of) Guy... Cox. ...... sv ebbs sae ones d dee teas 15 nan GEncory - Portrait..of Joseph Barrell... ...%...<06<.: ek ed Ae ng 18 wold ipvEnner: oortrait Of James E. Todd... siees ccs. dee Reais 44 “ 4—-KeriTH : Geologic map of Appalachian region...... Si aeolian, 309 oe aN EN DLE © UCONCHETIONS .. wih ee ese 1h S ime Sp Re RU ate cee Pa Tut es * 648 a aa COMEHETIONS fae foe eo hos ie oe bess oe See OAs ih a ne eae 648 BR ee Concretions..... aaa AiO 3 (aire ROR Be cae ee ts yor 648 - a the an Concretions= soiway oe. bs beets cake FN SER a ee tae 648 ey Oo ~ * CONnGFELIONRG 4. G6. 5 ee Se Rb dA ths BAe A ceae Mane gen rh css 648 nag... CONMGCKEHIONSS scsi ck 2 AR ot CRE a me Set PA ee Ae a ed 648 ES at is CONnGCTEHIONS . Socata e oe es Wot tach pane aimee Ee Ae, Sitios 648 Og bi DP OMNCEEI OMG ett e en ahs ae o sol OA ww ave Waddie els Beet 648 FIGURES SCHUCHERT : Figure 1—-Geosynciines, lands, and oceans or mediterraneans dur- UIT MPC WE CO LEK OLOIG TIMI Fy sn: See aol we ewe e.ik, 6 wie ate 21S oro -—North America in early Proterozoic time.............. 214 R S, geosynclines and embayments, and neutral ECA Sew ALO ZOTE mM Ch ie: fh, oie cates SA's ec ews vole eee 2AS - 4—Geosynclines of late Lower Cambrian time............ 216 © 5—-Geosynclines and their extensions of Upper Cambrian EMG CUM ACA TADIEY 55.54 ko se oo ievd shaeansiats ale sre HAG ek oe 24% ad 6—Geosynclines and embayments and Arctic Sea of Orde: * ICEL TELETYPE ae ge RO ee 218 ci 7—Geosynclines and embayments and Arctic Sea of Silu- ‘ TUM ANUN Se eek aed eh vys'er Sieaiteehiel Lay a lea) So ee Eat CN 219 be 8—Geosynclines, embayments, and their extensions during Devonian fime?..«.ss. 22. aries Cpe oe cancer oS 0! 220 4 —Cordilleran Ae ieline and Mississippian Sea of early MaSSISSH ODOT HIME. «462 cite 6 cid. Rikeee ins Vesey Betts 2 tate ey 221 + 10—Seas and embayments of late Mississippian time....... 222 Ks 11—Seas and coal swamps of early Pennsylvanian time.. 223 . 12—-Cordilleran, Mexican, and Franklinian geosynclines; Mississippian Sea and coal swamps of late Pennsyl- WATMIAM CAMR@. oc a. Re ea eR SCE Neer Ens siccm e's Sie a bs 224 H 13—Pacifie geosyncline, Arctic and Mexican seas of late PRIA SSUG THMS 2 alr Sees 5 ONE Fae Oh pe ae a es Ie ee 225 ey 14—Pacific and Mexican geosynclines and Logan Sea of Svelniee ORO et Tee CO FEC | Sees er 226 ey 15—Californian, British Columbian, and Mexican geosyn- clines of Middle Cretaceous (Albian) time.......... Dt 16—Great Rocky Mountain and narrow Pacific geosynclines and Gulf of Mexico overlap of early Upper Cretaceous PTE MEAN CS ONY ein, LSD Ap lacclarosaid! «6 Ss alee Sie Saii‘siince ave 228 X11 SCHUCHERT: BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page Figure 17—Great Rocky Mountain and narrow Pacific geosynclines LONGWELL: Figure Hopgs: Figure MANSFIELD: Figure LEE: Figure HOPKINS: Figure and Gulf of Mexico overlap of late Cretaceous (Pierre) CLINE. 6.05.5 5d 0 bk oa OA oe a phe eee oe eee 229 18—World chart showing geosynclines and hypothetic conti- nents during Mesozeie finite. 5. 2. toe eee 194 1—Schema der Gliederung des alpinen Orogen........... 233 2—-Blockdiagramm eines normalen (erweiterten) Orogen.. 234 3—Schema des Deckenbaues der Ostalpen und Dinariden.. 235 4—-Blockdiagramm eines mit einen Vorlande einseitig ver- senkten Orofen sss (oo. an ees OO Ac ele ow alerts 236 5—Blockdiagramm eines normalen versenkten Orogen, des- sen vorlande z, T. stehen geblieben ist............ eal 6—Blockdiagramm des japanischen Orogen............... 237 7—Blockdiagramm eines samt dem Vorlande versenkten QTOZENS 5. sc een BS Rete f ase abies cele ie ee: eee 238 8—Schema des Graben-Horsttypus......:....--..---s;aee 240 §—Schema eines gebirges mit massendefekt.............. 241 1—Contrasted maps and sections of the Asiatic continent... 248 2—Characters of the islands composing the Marianne Arc. 250 3—Comparison of the different sections of the Marianne Are 251 1—Distribution of the known great overthrusts in the northern -Rocky Mountains): . 525.55) sc. ose 25 an 2A—Attempted restoration of structure in the Rocky Moun- tains of southeastern Idaho........ os eee lean ane 274 2B—northeastern continuation of the section shown in fig- ure 2A, with the Caribou Range at the right....... 275 1—Relation of the interior Cretaceous Basin to the ances- tral Rocky Mountains, the Nevada continent, and the present Rockies... 2 0c 5 0.0. i we nee once a 287 2—Diagram illustrating deformation of isogeothermal planes and their relation to erosion................- 293 3—Relation of isogeotherms to a sinking earth block...... 294 4—Diagram illustrating the relation of erosion to the rise of a mountain Block. : .. oi e.008. sb bikes eee 296 5—Flow of heat in dike and adjacent rocks.............. 301 6—Readjustment of solid material under strain.......... 303 1—Deep wells of east-central Alberta, western Saskatch- GWM. . sn ks Sie Sere pete eee eee se 420 2-—General view of Tit HHS iicits ta oe se Sy mite o oie 421 3—Sketch map showing geologic structure of Mud Buttes.. 422 4—View of Mud Buttes from the southeast............... 423 >—Near view of part of Mud Buttes. . 2.0.00. 055 sen eee 423 HOPKINS: Figure oe sé oe ee 10—Development of structure of Mud Buttes ILLUSTRATIONS 6—Close VIVO Ve ES bese: Dette eteel coe oh a a he He OIGSO VLE Vyes OL Gas TEUES. ace a eh eredenel eg aaliees betas io etree ees RE SINGAEL Vil. On sy VETIC ees UGUGS «aps sete tote e aietale ane wee & o ellahe peed NPA VAC WO MeL Get ES LEDGES Palarseatete lel sate Gialetke avg Bis Poets. ay ecece ore eee ee se ee eee BOWEN AND AUROUSSEAU: Figure ee 6é VON HUENE: Figure 6s oe VON HUENE: Figure sé VON HUENE: Figure PATTON: Figure 6c CHADWICK: Figure STOSE AND JONAS: Figure 1—Geologic map of northwestern part of the Piedmont be 1—Core barrel from Montezuma well number 1........... 2—Thin-section of fused core, Montezuma well number 1.. 3—Micrographs of steel from core barrel................. 1—New restoration of Megalosaurus (Streptospondylus ) OPED rts SRR Mec siag CRBESR cot al SP ERO aes RA Pag let SN Ae a eR ic SoD 2—New restoration of Compsognathus longipes........... a OMG TNCHS CE HENINC ies” cemcciartiea s GettiasclGS Soatojeng & dlc A hee eine euler 1—Dicynodon sollasi Broom, right side.................. 2—Dicynodon sollasi Broom, from below................. 1—New restoration of the skull of Mesosaurus braziliensis from the wermian Ob PraheM Brazil. le os. Seek ele oo e's 2—Scheme of the phylogenetic development of the Ichthy- ETO NE STES IGEN Dek ke op nat el i AU A a Ag POP fe MaecOn INOMUR® WANKOUAK: coc Salas se ws «wits cae a ew Oe eee ET AOn SOME PAK ObAe sas cs wee eis Se acs x ois im cav a eee aces 3—Bijou Hills and gorge of the Missouri................ 4—View of East Bijou Hill, part of West Bijou, and the OM CENCE Ua ere eevet es eietehe jak ve. af atts, «i Sh oseweio cece a lel 6 mee & ack 5—Panoramic view of the lower Cheyenne River, looking southwest from the upland north of the mouth...... 6—View of portion of bouldery margin of Lake Arikaree, Nee ein ite im tie DackerOunG nn. ees. os... 1—Part of general section in which transition bed occurs. 2—Contact of Timpas limestone and Carlile shale......... -1—Evolution of the Laurentian Great Lakes during ice SINE TEASERS foes SS ae Ce ee province of Pennsylvania and Maryland............ 2—Limestone conglomerate at base of Conestoga limestone uncontormable on Ledger dolomite..:.............. 3—Uneonformable contact of limestone conglomerate con- taining subangular blocks of white marble at base of Conestoga limestone on Ledger dolomite............. 506 X1V BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page STOSE AND JONAS: Figure NELSON : Figure 66 se GOULD: Figure Uclow: Figure “e “ec “ec 4—Solution crevice in white marble of the Ledger dolomite filled with limestone breccia at base of Conestoga VIMESTONG.. 5 2 ss Rte he eS ee ets ce ea eee 512 5—Closer view of limestone breccia at base of the Cones- toga limestone in solution crevice in white marble of edger -dolomite:. 22.0... se .3 «0 ose ie ea tie ee 512 6—Rapid change in character of sediment of the Conestoga ' limestone; also bed of conglomerate......2.......0: 513 7—Thick-bedded granular dolomite passing into finely lami- nated impure ribbed limestone typical of the Cones- toga. Timestone wh 6. LAS ae oo cle Be Ge ee 513 &S—Thick bed of limestone conglomerate with underlying thin-bedded dark calcareous slate of the Conestoga limestone unconformable on massive Ledger dolomite. 515 9—Thinly laminated impure limestone characteristic of the Conestoga Limestone... ss. ecc.< . ois sudkmyew ss «oe anal 515 10—Closely folded and fluted gray and white banded mica- ceous marble of the Conestoga limestone in a small overturned ;SYNCNG +)... doc sicuek Bo.caok 6 ae eee 516 11—Fossiliferous beds in the Conestoga limestone......... 516 12—Geologic map of Chester Valley in the vicinity of Coates- Wille oc Sted Aeveie o bk daw ke NS, Seca enol aan 518 13—Geologic map of Chester Valley in the vicinity of Down- PVE COWS en case Sa Gis a Oe cove ialle! of as haze abies cee 519 14—Harly setlimentation si... 202 ae. os ke ee oe 522 15—Barly ‘uplift: and: erosion ws.01.%0s 20.2 aks. eee ee 522 16—Later Ordovician sedimentation and overlap........... 523 17—Later folding, uplift, and erosion...................:. 523 1—Geologic section across Missionary Ridge............. 529 2——Bed. of bentomite.c.c 5 o/c ciecsi< cents ane Exe eee 530 3—Diagrammatic sketch of west side of Isabella Stewart DaURIbe: MUME. oo 5 Fe se his oe vos oe ele» we baie «a eee 4—West side of the present Isabella Stewart bauxite mine 532 1—Location of occurrences of crystalline rocks on the PY QING . 56 CSS ee wh Ries Deeia ee tk bk eae ce ee 542 2—Relation of hypothetical Balcones-Arkansas-Ohio Valley line of weakness to adjacent masses; also exposures Of “IGNEOUS LOCK) oviece vc us Biatels Sela be Oo eines 546 3—Loeation of buried granite ridges in Kansas, Oklahoma, and Texas; also location of wells which have reached STATUELG © o6'c wks ale aier¥ dive nie, pak a areia er b etadin vara Yes ee arte 554 i—Key map of area: studied’:... 2... 0..5.6 Jus. eee 563 2—Sketch map of portion of North Thompson Trench..... 565 3—North Thompson Trench from Skull Hill............. 566 4—North Thompson River at Chu Chua.................. 567 BRETZ , Figure 6e KINDLE: Figure 66 66 se QUIRKE: Figure 66 ABER: Figure MILLER: Figure LANE: Figure ee 66 (12 plates; ILLUSTRATIONS XV Page 1—Glacial drainage features of east-central Washington... 574 2—-Steptoe Butte and the maturely dissected Palouse region GA St OL MCLS MCA WLAN SG?” wards eusteter anaphase alas Gee eaetes ate B DTT 38—Channeled “Scabland” of Spokane age................ 578 4—Spokane drainage channels in mid-length of Moses CWouleey ne as Be Sey etal er ea Pe Sa ee ee eta NG. oa 578 5—Rock Lake, in a glacial drainage channel of Spokane age 579 6—Glacial ice and drainage near Spangle, Washington.... 582 7—Post-Spokane talus in “The Potholes” south of Trinidad 591 8—Part of Drumheller Channels plexus.................. 596 9—“The Potholes’ near Trinidad, Washington............ 598 RO — One wate bMerlOrnOles!.cstismas <6 vee sre c ate Dekverees ue ate aie Boe 599 1 —Chitts 70k lower Mosés Couleee cc. 20. saa ee Yes Soe 602 Ae SOc Id nO ell EOC rs ae set ec eel hs! cok Gata shoe ate Svea ew ae hee es 604 1—Generalized Ottawa Pleistocene section............... 622 2—Sketch showing two levels of clay pits southwest of ETT eel RAE Ee Sone, Ws | r9, Awe ela kos eiatoy seh Siiohe abe outlaws 628 3—Caleareous root concretions exposed by wind erosion... 630 fe Skervch abe ivideansunction, Ontario....20. 24.2.0 ee fee. 632 i PHCOreLICaAl wparalel fOLGIMS. 6 cuts cele bc ereees eee Co aeons 650 pe MGA MU ORIOHITNH SOS esta oe Bele a tates! ol Gee 2a ahs cies abfole g scale evn aveie wi 651 3—Boudinage, Carriére de la Citadelle, Bastogne, Belgium. 652 4—Boudinage, Bastogne, Belgium....................000- 653 5—Formation of a boudin by lateral pressure—a rotational SSeS ner pee emt EM ak at ORS PAE C: Gy cysn che ta tu/etuye eid aides Siallale, Seda a 656 6—Recovery, clastic or otherwise, of a boudin, after release OerIAeTAle DLESSUECCiere — cto heh sic Hees om wai dace cera a 8 656 7—Boudin-like features due to drag-folding and cross-frac- ARE Se ey matt eas RS Fe es aa oe oP anaifoee Meee: Swen. Oe 657 aa MECITT Spey eN arene ue nett Stee coord Goatscele atdrela’ ss Wib-S'S eae © 6 658 9—Phacoidal structure and boudins bounded by schistose TRICKS eens Glee e ee EP eyeRa eS She ac ee cata al catihatataieie* oye tee soe 6 658 1—Principal faults on the San Francisco peninsula....... 665 eee ie INO es AMMICLICA oie ae 5 cole oo Use divine 0.88 ses ee ee ee 680 1—Differences from deepest gradient in Michigan........ T05 2 PeMOPeTAITES M1) WIGHIGAN. 650.06 wes ke vu ee ee eens T05 3—Temperatures in Lake well, West Virginia............ T05 125 figures.) XV1 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA PUBLICATIONS OF THE GEOLOGICAL SOCIETY OF AMERICA REGULAR PUBLICATIONS The Society issues annually, in four quarterly parts, a single serial octavo publication entitled BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA, ‘the edi- tion being 750 copies. A small supply of authors’ separates of the longer arti- cles is kept for sale by the Secretary at the prices quoted in each volume. 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Too ee eet ee ee 450 + xviii 14 7 Vol, 32; SOS ss uo See 488 + xviii 12 60 Vol. 33, AGE oe usin ke ee eee 862 + xxi 5 115 Vol. 84, T0225 oe ean an Gta eee ee 748 + xx 12 125 PUBLICATIONS PARTS OF VOLUME 34 (SnD ete CS ee Pimmber 2 se ak CO ES a UA eae LEE ELgeS See gaa RM ok kt bcc wale © PAGES. PLATES. 1-150 1-3 151-400 4 401-648 5-12 649-748 REPRINTS FOR VOLUME 34 REPRINTS. Proceedings of the Thirty-fifth Annual Meeting of the Geolog- ical Society of America, held at Ann Arbor, Michigan, Thurs- day-Saturday, December 28-30, -1922. C. P. Berkey, Secretary Proceedings of the Twenty-first Annual Meeting of the Cordil- leran Section of the Geological Society of America, held at Stanford University, Califor- meer 29. 1922: A.’ F. Roecrss, Secretary............. Proceedings of the Fourteenth Annual Meeting of the Paleon- tological Society, held at Ann Arbor, Michigan, December 28- a0, 1922. R. S. Basster, NSec- OR PP SE et Proceedings of the Second An- nual Meeting of the Society of Economic Geologists, held at Ann Arbor, Michigan, Decem- ber 26-350, 1922:.- S. H. Batt, RAPT P Sees oo ek wes ws Swe es Proceedings of the Third Annual Meeting of the Mineralogical Society of America, held at Ann Arbor, Michigan, Decem- ber 29, 1922. F. R. Van Horn, The work of Joseph Barrell on Problems in sedimentation. T. AV EAND VAUGHAN. .......... Sites and nature of the North American geosynelines. CHARLES SCHUCHERT.......... Kober’s theory of Orogeny. C.R. MPR RAEI an Ne. aes tia sid’ as wip's so The Asiatic arcs. W. H. Hopss.. Cross-section of the Appalachians in southern New England. J.B. US CODING LCT 2 eh PAGES. PLATES. 1-116 1-3 117-120 121-142 145-146 253-262 Ficu 38 ~ ( EF CO CO * Preliminary pages and index are distributed with number 4. + Under the brochure heading is printed PROCEEDINGS OF THE PALEUNTOLOGICAL SOCIETY. XV PRICE TO PRICE TO RES. PeL_LOWwS. PUBLIC. $2.40 3.85 4.05 1.50 PRICE TO PRICE TO .10 .10 10 .10 IGURES. Pertows. PUBLIC. $1.85 XV1IL BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA PRICE TO PRICE TO REPRINTS. PAGES. PLATES. FIGURES. FELLOWS. PUBLIC Structure of the Rocky Moun- tains in Idaho and Montana. G2. MEA Nereer 263-284 ae yi $0.20 $0.30 Building of the southern Rocky Mountains. (Wo) SEE. secant 285-308 tea 6 .25 .40 Outlines of Appalachian struc- sure.) A) ees os. ee ee 309-3580 4S uk ay (3) 1.15 Contribution to the hypothesis of mountain formation. Fe7 ANDREWS: sis fice ck i Hee e 381—400 SE ES ies .20 30 Recent progress and trends in vertebrate paleontology.; W. ED.) MATHEW: oss a oe 401-418 ae Cee .20 .30 Some structural features of the Plains area of Alberta caused by Pleistocene glaciation. O.B. IOP RING! os oe so coe eae eee 419 430 aed 10 .10 Bu 124 Fusion of sedimentary rocks in drill-holes. N. L. BowEn and BM~<-AUDRDUSSEATIat oo cert Se 431448 a ge 3 .20 .30 Carnivorous Saurischia in Eu- ; rope since the Triassic.y F. VON IVES Life Coe sete soci 449 458 sey 3 .10 15 Contribution to the vomer-para- sphenoid question.; E. von IPRS S 24 et oat se ee 459-462 2 10 15 Lines of phyletic and biological development of the Ichthyop- terygia.j EF. von HUENE...... 463-468 ya .10 .15 Is the channel of the Missouri River through North Dakota of Tertiary origin? J. E. Topp... 469-494 Nees 6 i .40 Merging of Carlile shale and Timpas limestone formations in southeastern Colorado. H. SE RECON C25 G oo ea ala eee 495-498 2 .10 15 Glacial lake problems. G. H. EM OA ek oe ck ee Rae 498-506 JS ess 1 .10 15 Ordovician outcrop in the Pied- mont province of Pennsylvania and Maryland. G. W. STosE Sn Ante lO SONAS Ss 2.3553 kk 507-524 aba 17 .20 .30 Appalachian bauxite deposits. W-As RESO so a otc cle ee tee Mere 4 15 ~20 Crystalline rocks of the Plains. hs TE rp RaRSR Rees ira cuaee Sy Hae Wea 541-560 3 20 .30 Cretaceous age and early Eocene uplift of a peneplain in south- ern British Columbia. W. L. UGE eos hd Sela de ate nites 961-572 oats + .10 15 Glacial drainage on the Columbia Plateau: 23. is BRE ee 573-608 sy gb .oo .Do + Under the brochure heading is printed PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY. PUBLICATIONS x1x , REPRINTS. PAGES. PLATES. FIGURES. pene eee ae Range and distribution of certain types of Canadian Pleistocene concretions. HE. M. KInpLe.... 609-648 5-12 4 $0.60 $0.90 Boudinage, an unusual structural phenomenon. T. T. QUIRKE... 649-660 Sayre 9 .10 rgd Some criteria used in recognizing active faults. STEPHEN TABER. 661—668 are 1 “10 15 The Lake Superior geosyncline. ewe LLOTCH KISS: .).).c0. 0 lef. 669-678 NE ST es oY .10 15 Pre-Cambrian folding in North mumerica.- W. J. MILLER. ...... 679-702 haps it 25 .40 Geotherms of Lake Superior cop- per country. A. C. LANE...... 703-720 3 .20 0) Cambro-Ordovician section near Mount Robson, British Colum- peeled). E> WREAEING so s.o es ass. « 721-748 Se ts Vibes ie We oO) 45 IRREGULAR PUBLICATIONS In the interest of exact bibliography, the Society takes cognizance of all pub- lications issued wholly or in part under its auspices. Each author of a memoir receives 40 copies without cost, and is permitted to order any additional num- ber at a slight advance on cost of paper and presswork; and these reprints are identical with those of the editions issued and distributed by the Society; but the cover bears only the title of the paper, the author’s name, and the state- ment [Reprinted from the Bulletin of the Geological Society of America, vol. —, pp. —, pl. — (Date)]. Contributors to the Proceedings and ‘Abstracts of Papers” are also authorized to order any number of separate copies of their papers at a slight advance on cost of paper and presswork; but such separates are bibliographically distinct from the reprints issued by the Society. Regular Editions Pages 151-880, plate 4, 50 copies. June 30, 1923. ut 151-230, ZEO at e 30, 1923. cf 231-242, DOL cick Pe 30, 1923. ri 243-252, fe ee es 30, 1923. ‘ 253-262, Oa * s 30, 1923. >) 263-284, ZOOn a0. yr 30, 1923. a 285-308, 140)" i. 30, 1923. Hf 309-380, plate 4, 210 ‘“ rg 30, 1928. S 381-400, BOS is 30, 1923. Fa 401—418,*+ 310, 0 elena September 30, 1923. ae 419-430, hs Vie ee < 30, 1923. zi 431-448, 600 “ a Oa: as 449-458, * 7 SLO ae i 30, 1923. “ . 459-462, *7 34 ea ae oes OO LOB “ , 463-468,*+ SLO oe 5 30, 1923. ss 469-494, (Cad ye 30, 1923. i 495-498, BOE as fe 30, 1923. ot 499-506, AHO. Rs 30, 1923. . 507-524, 1 9 a es. 30, 1923. re 525-540, 450 eg is 30, 1923. “541-560, HOM St y 30, 1923. oot eee a ae TO ae T P ate 5 ee GS ae ee XX BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Pages 561-572 50 copies. September 30, 1923. 573-608, 50 30, 1923. FS 609-648, plates 5-12, 8 “ x 30, 1923. - 649-660, — POG December 30, 1923. 4 661-668, g Ua | Saparea 30, 1923. is 669-678, 250 .-- 48 a 30, 1923. " 679-702, > a a 30, 1923. 703-720, S00, =“ 3 30, 1923. 721-748, 71 Eoeeigs e 30, 1923. Npecial Editions = Pages 15-— 18, plate 1, 50 copies. March 30, 1923. Ee 18— 28, plate 2, 110 = 30, 1923. i 28— 44, a | Nee = 30, 1923. “ 44— 50, plate 3) 500 «* 7 30, 1923. = 68— 69, Zale va" y, 30, 1923. fe 117-120, | eit fe 30, 1923. sf 121-142, *F Hes or (er - 30, 19238. = 143-146, BO " 30, 1923. . 147-150, ZT * 30, 1923. CORRECTIONS AND INSERTIONS Contributors to volume 34 have been invited to send corrections and inser- tions to be made in their papers, and the volume has been scanned with some care by the Editor. The following are such corrections and insertions as are- deemed worthy of attention: Page 111, line 1 from top, for “Molengraaf” read Molengraaff ch 113, line 17 from top, for “Christ Church, Canterbury College,” read Canterbury College, Christ Church 116, Summary, for “Original Fellows 25,” read “Original Fellows 26” ‘116, Summary, for “Membership 488,’ read “Membership 489” ‘* 146, line 4 from top, omit word “iron” * 270, footnote 19, for “Manuscript submitted for publication,” ete., swb- stitute Bull. Am. Assoc. Pet. ea vol. vii, 1923, pp. 1-13 413, footnote 40, insert after “no.” 78, May 25, 1923 432, line 2 of figure title, for ‘ Peas read contents 435, bottom line, for “‘proportoin” read proportion ‘506, explanation of figure 1, the finer vertical lines represent the “division-lines crossed by drainage”’ 515, title of figure 8, line 3, for “Ledger dolomite” read Vintage dolo- mite * Bearing on the cover PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY. [Reprinted from the Bulletin of the Geological Society of America, vol. ——, pp. ——, pls. , (Date).] + Under tLe brochure heading is printed PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY. + Bearing imprint [From Buu. Geox. Soc. AM., Vou. 34, 1922.] BULLETIN OF THE Geological Society of America VoLuME 34 NumBer 1 { MARCH, 1923 4a f ays ~~. ¥E a “SoMa dal Wine PUBLISHED BY THE SOCIETY MARCH, JUNH, SEPTEMBER, AND DECEMBER CONTENTS Proceedings of the Thirty-fifth Annual Meeting of the Cea logical Society of America, held at Ann Arbor, Michigan, Thursday-Saturday, December 28-30, 1922. Charles P. Berkey, Secretary. -. - -.- >= + (2 =) eee eee Proceedings of the Twenty-first Annual Wie cane of the Cor- dilleran Section of the Geological Society of America, held at Stanford University, California, April 29, 1922.. Austin F. Rogers, Secretary. -_- - - -7- « = = Proceedings of the Fourteenth Annual Meeting of the Paleontological Society, held at Ann Arbor, Michigan, December 28-30, 1922. R.5. Bassler, Secretary - - - Proceedings of the Second Annual Meeting of the Society of Economic Geologists, held at Ann Arbor, Michigan, December 28-30, 1922. Sydney H. Ball, Secretary. - - Proceedings of the Third Annual Meeting of the Mineralogi- cal Society of America, held at Ann Arbor, Michigan, December 29, 1922. Frank R. Van- Horn, Secretary pro tempore:; - 9 - <0 =. 49 =|} ye = ee Pages © 117-120 121-142. 143-146 147-150 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Subscription, $10 per year; with discount of 10 per cent to institutions and libraries and to individuals residing elsewhere than in North America. Post- age to foreign countries in the postal union, forty (40) cents extra. Communications should be addressed to The Geological Society of America, 77th Street and Central Park, West, New York City, or care of Florida Avenue and Eckington Place, Washington, D. C. NOTICE.—In accordance with the rules established by Council, claims for oy non-receipt of the preceding part of the Bulletin must be sent to the Seeretary — _ of the Society within three months of the date of the receipt of this nner) -0 order to be filled gratis. Entered as second-class matter in the Post-Office at Washington, D. C., under the Act of Congress of July 16, 1894. Acceptance for mailing at special rate of postage provided for in Section 1103, Act of October 3, 1917, authorized on July 8, 1918, PRESS OF JUDD & DETWEILER, INC., WASHINGTON, D. C. t . BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA ~ MOL. 34, PP. 1-116, PLS. 1-3 MARCH 30, 1923 PROCEEDINGS OF THE THIRTY-FIFTH ANNUAL MERTING OF THE GEOLOGICAL SOCIETY OF AMERICA, HELD AT ANN ARBOR, MICHIGAN, THURSDAY-SATURDAY, DE- CEMBER 28-30, 1922. Cuarues P. Berkey, Secretary CONTENTS Page nero inrsay mormins.. December. 28.00... b ccd ec ee ee eee tee dD Uo LD“; OME SRDS Cth Ov Grd ISS tn ee a es ee ey en 6 |S 2 UEVTERTET SUAS OWE i cet te es Cn a OR re nn 6 oy EEE REE SOMES) C001 open Ce ee a Ian io a 9 MSMR MICE ATE etn aw) Sarat ah Sra, Sp peep ch Sh alte) asi wr ch SP apiae chs Va vewbieradgvelane NIT 3580 10 Picaiene Or rAvOitine . COMMITEE sis. e oes bien elds aha oath e ie we eee ees at Election of officers, members of standing committees, and Fellows... 12 Vote on proposed amendment to the Constitution................... 138 Introduction of Correspondent Emmanuel de Margerie.............. 14 Report of the representative to the International Geological Congress. 14 Eeport.or Committee on Teaching Geology ...: 0.0.5 sececcec cbse ecens 14 ae INI eds 20h no a Src c wo See enero te hia’, Sod oad Be hs eaa ewes 15 Memorial of Guy H. Cox (with bibliography) ; by C. L. Dake... 15 Memorial of Joseph Barrell (with bibliography); by Herbert E. ee EP Ren Alder pit Fats S Sten g laaEE ue oe svete oe Saket a, eh need 18 The work of Joseph Barrell on problems in sedimentation; by Cm Sm TEL, NAUSINAT. oc cca wha che eiane. es) ed bs 8S 6 eles seve 0% 28 Memorial of James E. Todd (with bibliography) ; by Frank wit TRIBE E Aco Scr i fy tcvee espace see neue We MEE Rta RI Mt ek a a4 Memorial of Levi Holbrook; by James F. Kemp.. ............. D1 Me weOreneerTeLirims PreSigent....0.002 heal as sl otk lee ces eeecwae D2 ereeeee TINT AY nD LETINOOM co: aac gs ass ood eS etal clea ea cee cc ccleacesaces a3 Pett Oe) ADE TS Eh PGESCMECC 2... 25S). crates Ssieic vnerahscclc-d see le'e'oactes ec cecucces -O3 Symposium on the structure and history of mountains and the causes MERWE HIS CW CNOIITIGOTNE «| os ci sia ui s0s Gps wae edie w cc ee wlerec ree co cave neces D3 Sites and nature of the North American geosynclines; Presiden- iaaanress Dy tonathes Sehwcherts ).<.)bo.c026. fo ce ceca eee 53 The theory of mountain structure recently set forth by Professor oper or Vienna > by Chester R. Longwell...... ..........-.. a3 Pe eee AVI TAT NaS TODDS iver cictecel le Ses Sas ca cedeeocloces 53 ere Appalachians: by Arthur Keith........... ....2.s0cececes. 53 if Bonu, Grou. Soc. AM., Vou. 34, 1922 bo PROCEEDINGS OF THE ANN ARBOR MEETING Page Eastern Appalachians in the latitude of southern New England: by J.-B. Woetworth.00 3c. ess hw cee eee 0 ce a Coast Ranges and Sierra Nevadas; by Bailey Willis............ 53 Rocky Mountains of Idaho and Montana; by G. R. Mansfield... 55 Front ranges of Colorado and New Mexico: by Willis T. Lee.... 54 Session of “Thursday eVBGIg <5 6.4.86 xtc bo he eke ae ee Ce -by Douglas. W.' Johnson. «co. cc oa oe oT Dynamics of faulting and folding [abstract]: by Harry Fielding Regd ek s.. Soc Se k.g se VR es Ce ae Rete chr e enh St ok soe Criteria for the recognition of active faults; by Stephen Taber... 58 Fault map of California [abstract]; by Bailey Willis........... DS Faults of the Coast Ranges of California [abstract and discus- sion]; by Bailey” Wills... 20.0 Soe so as Ob. Cee DS Late Tertiary and Quaternary diastrophism in southern Cebu. Philippine Islands [abstract]: by George ID. Louderback and BR. Re. MOTSC ie ioe crn wie dio pin br Si ee alte ee) we gee a9 Parallel folds and boudinage [abstract]: by Terence T. Quirke... 59 Group photoerrapli . «occ 6.6 cs nk ee ee Saar 60 Luncheon given. by the’ University i < Sck is Oo oc cro. eee : by H:.B. Patton. 2.6... Ses cod cc ewe ws 74 Present status of the geodetic work in the United States and its value to geology [abstract]; by William Bowie............... 74 Reconnaissance traverse from Mojave Ulojane, California, to Rock Creek, Utah [abstract]; by Herbert E. Gregory Topography and geology of the Okanogan Highlands and Colum- bia Plateau of Washington [abstract]; by Solon Shedd........ i Tertiary stratigraphy in the lower Rio Grande region [abstract] : pene WO. sO WOT VOTE Sich o.)) ke a)c.a 1 Gs6 dime esvbere thee a be Sialaie 75 Seman MEU HUELENE Tear rateatale Get eset, cos Ree 2 AS om wc igoal cid wives wc bre oh 6 wake ws (6) See nS pt OMT TN SOCICEICS 6 aie o 5 u's san bce un albu oe oc ade due Sew ean eelene' 76 Resolutions of appreciation to E. O. Hovey, retiring Secretary....... 76 Peta yen OLS TIOVCY 0. 2). 5 ss ook Pw Se oe Cab ee cba se ae eek 17 4 PROCEEDINGS OF THE ANN ARBOR MEETING Session -of Saturday:-morning; December -S0e oes aah cil ee eens Titles and abstracts of papers and discussions thereon, presented be- fore. the. morning: .S@SSIORY . ou Bees oe ee ee ie ae ea eee Geological reconnaissance in Mongolia [abstract and discussion] ; by Charles: P: - Berkey . 2.3325, cae: 2 eee oe ee eee Problem of mild geological climates [abstract]: by Ellsworth Hun Ane tO ss x.0.00 3 Sierra ea oe ben el = een ier ee Further experiments on the fracturing of hollow brittle spheres and their bearing on major diastrophism [abstract and discus- sion ].;-by «Walter A. BuGner. Aun hes 5 eis 2 ee ee Some structural features of the plains area of Alberta caused by Pleistocene glaciation; by Oliver B.-Hopkins................. Correspondence between the Gondwana system of Hindustan and the Newark system of the eastern United States [abstract and discussion] ; by William Hic Hobbs .2%. 2622 eo ee ee eee Quantitative criteria in paleogeography [abstract and discus- sion};-by Raymond: 'C. Moores 22.2 20 eke 5a eee bee Keweenaw geothermal gradients and the ice age [abstract]; by Alfred: Gane ss ee eee eee oe ere ke ee Votes of thanks ir ic-5 6 Side 2 a kc SE ee eee eae a Oe Titles and abstracts of papers of Group A and discussions thereon... Physical history of the Colorado Front Range [abstract]: by ¥F. M. Van" Tuy! ‘and G:. Wy Machamer. 5.5.4.2. 6 2. eee eee Structural features of the Colorado Plateau and their origin: by Raymond "Os" MOOrE oo iascn toamle ge aie Biase. Ou ian ees REE ee Structure of the Spring Mountain Range, southern Nevada [ab- ‘stract]':-by- D.. BE Hewett.<. 5 4 Soa Be ee Pleistocene of northwestern Illinois: a graphic presentation of some of the chief lines of evidence [abstract]: by Morris M. Leighton 252 oe Sk eX vod w he ENELS Meee Pe Oi Fossiliferous loess beneath tilted Galena dolomite at the border of the Belvidere lobe, in northwestern Illinois [abstract]; by Morris M. Leighton... 22 onto s }- tne ew ee oe eee Late Tertiary and Pleistocene terrace plains of the middle Atlan- tic Coastal Plain [abstract]; by Chester K. Wentworth....... Glacial deposits of Missouri and adjacent districts [abstract]; by Frank Leverett. oo. 5 00.2052 445 OF. Wien ee ve ie Se Glacial drainage on the Columbia Plateau of Washington: by J. Ebarter > Bretz. cc os. eS Oca sie 8 mee Bate a ee Glacial lake problems [abstract]; by George H. Chadwick....... Ice action on inland lakes [abstract]; by Irving D. Scott........ Banded postglacial clay near New York City [abstract] ; by Ches- ber A "ReGds is oiio8 ote artiecariers «dean ee ee Origin and history of extinct Lake Calvin, Iowa [abstract]: by Walter .B: Sechoe wes oo eo i ce be Physiography of the Paria River valley, southern Utah [ab- stract!: Dy “Raymond. <3. . Moore. 5.3 2c. 04.4 ie eee ‘ CONTENTS Page Sand rivers of Texas and California and some of their accom- panying phenomena [abstract]; by Robert T. Hill............ 95 Sedimentation at the mouths of the Mississippi River—prelimi- nary report [abstract]; by Arthur C. Trowbridge............. 95 Geological map of the Bushveld complex, Transvaal, South Af- rea aAstracs | s, Dy wCharles: Palacio co ocatminet ss Soeur. oes x 95 Titles and abstracts of papers of Group C and discussions thereon... 96 Metamorphism of quartzites by the Bushveld igneous complex PAS eu reo es yee wr Oey yen OMY PIANG cck-6 Srey atcme ea clears wie tone Roo o goale. clade 96 Fusion of sedimentary rocks in drill-holes [abstract]; by Bailey MONAT Sat coreeteceteeh. premier ere eter ts a) cop ket Oye ee So Pe a Garg ae Oe 96 Fusion of sedimentary rocks in drill-holes; by N. L. Bowen and TL 8 TRIES CoD ISSO NB NE CR, Pe i opti ll a 8 Aa 96 Xenoliths in the Stony Creek, Connecticut, granite [discussion | ; PATHS At ROTM e y(t hat Seki rh< oe Dees eek as Sa PSO TS 96 New teaching diagram for igneous rocks; by A. B. Van Esbroeck. 97 Aerolite from Rose City, Michigan [abstract]; by Edmund Otis NM ee NE De Ltn arc aw Din eee sola ee eS Lie Nab RRL ee ee OF Origin and formation of certain Appalachian bauxite deposits; by STL SETE Gaeta IST DER ae CS aie Sh” SEAGATE aR na a ae a 97 Stormberg lavas of South Africa [abstract and discussion]; by TOT EG too TERNS TET ESTO Bian Ste 7 A Soa ae eal 97 A high temperature vein in Madison County, Missouri [abstract] ; He CU, aS CUBS aS es lear Bl SU re eh SN a wg Pa a 99 Cretaceous age and early Eocene uplift of a peneplain in the southern interior of British Columbia and the development of ° the north Thompson River trench; by W. L. Uglow........... 99 Study of the igneous rocks of Ithaca, New York, and vicinity eaters lel es MW ey Ede. NEAR OTA ee a se Sess Sie ale cce w aestes « 99 Attempt to study the actual capillary relationships of oil and Mabe orausimaceie Dy Charles Wi. Cook. oc. oic.c cc keds eke cae. 100 Chemical suggestions concerning the origin of Lake Superior cop- PeISOLes | aUserack | js by toeer’O:; Wels. occ. ck ce ck oa 100 Solvents and precipitants in the Michigan copper lodes_ [ab- SamieAne te ee FNS CL Gs T EEC wyctaiere sc) tele baal a i iecd.2 oe: depois o'+ cae wes. 100 berate the Anim Arpor meeking, 1922... fs ec ee eee ce ee eee ee 101 ererence to Constitution and By-laws... 6066 os ce ee ee ce eee ce 102 Officers, Correspondents, and Fellows of the Geological Society of America 103 Session OF THURSDAY MorNING, DECEMBER 28, 1922 The Thirty-fifth Annual Meeting of the Geological Society of America was called to order in the Natural Sciences Building of the University of Michigan, Ann Arbor, Michigan, at 10.22 a. m., by President Charles Schuchert. Brief remarks reminiscent of the influence of the University of Michigan in American geology were made by President Schuchert, 6 PROCEEDINGS OF THE ANN ARBOR MEETING who called attention to the fact that this was early a center of geological activity under the influence of Alexander Winchell, the real father of the Geological Society of America and one of its earliest Presidents, as well as under his successor, Israel C. Russell, who also became a Presi- dent of this Society. He poimted out that Ann Arbor, both because of its former great influence and also because of its continued prominence to the present day as an active center of geological teaching and investi- gation, is a very appropriate place for this annual meeting of the Geolog- ical Society and its affiliated societies, covering the geologic, mineralogic, paleontologic, geographic, and physiographic fields of investigation. REPORT OF THE COUNCIL The report of the Council was presented by Secretary Hovey, as fol- lows: To the Geological Society of America, in thoirty-fifth annual meeting assembled: The regular annual meeting of the Council was held at Amherst, Massachusetts, in connection with the meeting of the Society, December 28-30, 1921. A special meeting was held in New York on October 15, 1922. - The details of administration for the thirty-fourth year of the exist- ence of the Society are given in the following reports of the officers: SECRETARY'S REPORT To the Council of the Geological Society of America: The Secretary’s annual report for the vear ending November 30, 1922, is as follows: Meetings.—The proceedings of the annual general meeting of the Society, held at Amherst, Massachusetts, December 28-30, 1921, have been recorded in volume 33, pages 1-186, of the Bulletin. Those of the Cordilleran Section, pages 187-190: of the Paleontological Society, pages 191-222; of the Society of Economic Geologists, pages 223-226; of the Mineralogical Society of America, pages 227-230, of the same volume. Membership.—During the last year the Society has lost five Fellows by death—John C. Branner, R. D. Salisbury, James E. Todd, Levi Holbrook, and G. H. Cox. The names of the twenty-one Fellows elected at the Amherst meeting who qualified have been added to the printed list. Six Fellows have resigned or been dropped for non-payment of SECRETARY S REPORT - dues. The present enrollment of the Society is 463. Sixteen candidates for Fellowship are before the Society for election and several applications are under consideration by the Council. Distribution of the Bulletin.—During the past year there have been sent out to subscribers 158 copies of volume 33 of the Bulletin. Five volumes have been distributed gratis, as follows: Library of Congress, American Museum of Natural History, the Government Geological Sur- veys of the United States, Canada, and Mexico. Fifty-eight copies have been sent to our foreign exchange list. The receipts from subscriptions to and sales of the Bulletin and separate brochures therefrom appear in the following table: PROCEEDINGS OF THE ANN ARBOR MEETING Bulletin Sales, December 1, 1921—November 30, 1922 Complete volumes. | i | Brochures and parts. Grand total. Fellows.| Public. Total. Fellows.) Public. | Total. | i — Vooluumne Bn eo os ce 5 Seema aie cee ame in NR rca ca Volume: 2i Sol Seale eee Hee ere eee $1.74 | $1.74 $i. 74 VGiimG 3 ee SG ol eee eae ee eee $1.25 225 1.70 Eb Volmme. 46 0 sl ee lee eda eer ereenny ieee 20 | ae . 20 VOR. CHIE Le ee lo oe ee eee ee ee .30 1.03) aS 1.35 Volume ®e. Sie. tock olk Cee ee oe eee .1d UO es 1.80 Volumes tl sccte eee ee $7.50 De DO ase eee bes ee 7.50 Vottinie= &. Soiecar es ORs Gra ahh eae ie Bae ea ove eer ee 1.88 1.88 1.88 Volimmae Oi) 6 ce a ST Rew See ss ere an Volume 10... wha whe ed SRE EEA wre Peele eg cale hoyle nd lee? | crate pele ll oe rr Vibe: 1 <3 en Sc oe = ce ae anal ene ae £30 > Es38 1.30 Volame 12 «(ee Peers 85 ay eae de area Volume 13 20.3). 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REPORT OF THE TREASURER 9g TREASURER’S REPORT To the Council of the Geological Society of America: The Treasurer herewith submits his annual report for the year ae November 30, 1922. The membership of the Society at the present time is 463, of whom 372 pay annual dues. Twenty-two new members were elected at the last annual meeting, 21 of whom qualified. One elected in 1920 also qualified, making a total of 22 new members. Jour members commuted for life, making the total Life Membership 91. There have been 5 deaths during the year. When the books closed for the year 26 members were delin- quent in the payment of dues—2 for 4 years, 3 for 3 years, 4 for 2 years—and are therefore lable to be dropped from the roll, and 17 for 1 year. 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Investments : 1 Braden Copper Mines bond............ $1,010.83 1 Commonwealth Edison Company bond.. 1,002.22 Balance in Baltimore Trust: Company. .. <2... 05 Jes se% Respectfully submitted, Epwarp B. Epiror’s Report To the Council of the Geological Society of America: PROCEEDINGS OF THE ANN ARBOR MEETING $2,175.90 216.50 3,444.35 93.00 7.00 2,013.05 3,886.30 $11,836.10 MATHEWS, Treasurer. The following tables cover statistical data for the thirty-three volumes thus far issued: ANALYSIS OF COSTS OF PUBLICATION Cost. Average— Vols. 1-30. Vol. 3]. Vol. 32. Vol. 33. Bae See | $$ | pp. 737. | pp. 468. pp. 506. | pp. 883. pls. 31. pls. 14. pls. 12 pis: 6. | oT a a |e SoS. a RE A A, SS AI | $1,776.16 | $1,541.45 | $1,883.18 | $3,006.32 PRIMER CII oes cian Sree, Codd tees Ls ee eae eS 433.34 131.94 272.44 616.01 PDO cs Ae eck nS ecaeierneeea ces Sone eee 428.12 266.64 792.00 686.81 pS Ip eS ea ne Sp, ie es Aly Bee eye ad $2,566.03 | $1,940.03 $2,947.62 | $4,309.14 = =| AWREEQE: PRY PARE aiden neeahnun ae ee a eee $3.51 $4.15 $5.83 | $4.85 | a EDITOR S REPORT ti CLASSIFICATION OF SUBJECT-MATTER | | > P | : 2 US Pa a Ue Pa i Re = g : Beeb -| Sa eah en seiacb e212 Bee | ot Bele ol ee eel eal of eS Volume. ae s =e eet eS Sis eee a | ea ) <4 Total. - = Ss - ee] se) Be Be ee 2 E a) ieee be te ta iets Wh ele |S < £ o | a | a) fe) = =) Number of Pages. ae 6-1 137 92 8 83 44 = a ane a 60 4 4) 593+-x1i 2 a 36 | 110 60 | 111 52 | 168 47 | 9 || 55 1 7| 662+-xiv 2 ee 56 41 44 4] Be toe | 104-4. > 61 15) 1} 541+ xii a a 25 | 134 38 74 52 52 2 0 eae 47 32 | Z| 458-+-xii en 138 | 135 7 54 28 ge ME ee faa 14 | 9) 665-+-xii Be rey 0-7 491 7d 39 71 99 I dy ee ot 63 25 | 4) 5388+-x "aaa 38 77 :| 105 53 40 7A an Vi br 3 4 66 28 13) 558+~x Peas) 34 50 98 5 43 67 08 | 14 79 8|___.| 464 x ae ZAI OT 4 es oo (en 28 64 16 64 18 oie 60+~x | 39 33 96 37 59 62 68 28 84 27, 17) 534+-xiii Lr No a 65 | 110 ZA 10 54 31 | 188 7 71 60, 46) 651+-xii | A oa 199 39 dD 503 24 98 a a Fi 2|-...| 598+-xi eens, 125 eA 13 24 28 | 116 42 4 || 165 32| 29) 583+-xii Ne 48 47 48 59 | 183 | 118 22 1 80 14 1} 609+-xi ae My | 124 3 94 BV Lead | bins cellu Pilbas. ve 17 3) 626+x Wepre 64 | Lil 78 30 | 102 | 141 US fu iene 67 22; 18) 636-+-xili | ieee ea 49 | 161 41 84 47 | 294 27 fei 71 9 2| 785+-xiv ‘ys See H 164 | 141 D 29 | 246 Ee eee aes 68 40 3) 717-+-xii ‘| Seep 106 | 108 29 66 30 | 155 Bere oes 56 15} 20) 617+-~x v2, | SO 43 54 19) 29 ay 45 | 303 | 8 60 3) 132) 749+-xiv 7, | Sa a2 | Zot 79 48 89 70 | 106 1 lil Jl. 10} 8284 xvi 27 aS 23 o4 28 28 743) LE ee Ce 63 49 1) 747+-xii ae ip see | 126° | 108 5 I ce Sa as b= Si 66 32 | l| 758+-xvi 7 J: a Naa 18 a7 96 a7 49 | 160 | 106 25 ll too 50 3) 737--xviii Pe oA } Zit a4 32 | 156 OF i Io 108 9; 22) 8024 xviii CS EG ae Road hed 3 11 56 90 | 148 |.___- 04 44 6| 5044 xxi “1 SN Oey 1 9 | 125 31 | 146 re 1 tab arb 2 io 24\ 98| 7394 xviii /::, TS 2 | Zio 70 69 78 | 200 33) 39 94 | 110) 14/1005+-xxii ge 3 | 107 62 15 | 127 | 169 64: joe he 73 a7) 621) 6794+-xix 2 ee 160 3 41 4 5 386 | 205 16 ia 599; 80) 6444+-xili 2 ea 20%: 30 19 4 i3 45 oe ZA 69 97) 79) 450+-xvili ens 73 47 fi 72 63 H 77 17 || 105 2) 37) 488+-xviii Bae ee, 39 | 166 | 160 47 7 | 107 | 101 3 91 | 41 31| 862+-xxj Respectfully submitted, Ties JOSEPH STANLEY-Brown, Editor. The foregoing report is respectfully submitted. THE CoUNCIL. December 28, 1922. ELECTION OF AUDITING COMMITTEE _ The printed report of the Council was distributed to the members in attendance and was available for additional circulation. Since the report of the Council contained the Treasurer’s report, it was laid on the table 12 PROCEEDINGS OF THE ANN ARBOR MEETING pending report of an auditing committee named from the floor, consist- ing of H. B. Kummel, Harry Fielding Reid, and R. T. Chamberlin. ELECTION OF OFFICERS, MEMBERS OF STANDING COMMITTEES, AND FELLOWS The Secretary then declared the vote for officers, members of standing committees, and Fellows for 1923, resulting from the canvas made by mail, as follows: President: Davin Wurte, Washington, D. C. First Vice-President: Witi1am H. Hogpps, Ann Arbor, Michigan Second Vice-President: Wittram H. Emmons, Minneapolis, Minnesota Third Vice-President: T. WayLanp VAUGHAN, Washington, D. C. lice-President to represent the Mineralogical Society of America: Epear T. WuHerry, Washington, D. C. Secretary: Cuaries P. Berkey, New York City Treasurer: Epwarp B. MatHews, Baltimore, Maryland Editor: JOSEPH STANLEY-Brown, New York City Councilors (1923-1925) : EpmuNbD Otis Hovey, New York City AurreD H. Brooks, Washington, D. C. Representatives on the National Research Council (July 1, 1923, to June 30, 1926): ApoLpH KNopr, New Haven, Connecticut FrepertcK B. Loomis, Amherst, Massachusetts ELECTIGN OF OFFICERS AND FELLOWS ts Members of the Standing Committee on Teaching of Geology (1923-1925) : Exiot BLACKWELDER, Stanford University, California WarREN J. Mreap, Madison, Wisconsin FELLOWS ‘Leason H. ApDAMS, B. S., Geophysical Laboratory, Washington, D. C. EUGENE T. ALLEN, Ph. D., Geophysical Laboratory, Washington, D. C. PauL BiLuiInGsteEy, A. B., Anaconda Copper Mining Company, Portage, Wash- ington. JOHN StTarrorD Brown, B.S., Associate Geologist, U. S. Geological Survey, Washington, D. C. Kirk Bryan, Ph. D., Geologist, U. S. Geological Survey, Washington, D. C. Victor DoLMaAGE, Ph. D., Canadian Geological Survey, Ottawa, Canada. JAMES WILLIAMS GIpDLEY, Ph. D., U. S. National Museum, Washington, D. C. AnNA I. JonAS, Ph. D., Bridgeton, New Jersey. BERTRAM ReEtD MacKay, Ph. D., Geological Survey of Canada, Ottawa, Canada. ALEXANDER Watts McCoy, M. Published by permission of the Director of the U. S. Geological Survey. * Taken from list by Charles Schuchert. Am. Jour, Sci. (4). vol. 48, 1919, pp. 277-280. 1908. 1909. 1910. 1912. 1913. WORK OF JOSEPH BARRELL ON SEDIMENTATION 29 Origin and significance of the Mauch Chunk shale. Bulletin of the Geological Society of America, volume 18, pages 449-476. Abstract in Science, new series, volume 25, page 766. Relations between climate and terrestrial deposits. Part I, Relations of sediments to regions of erosion. Journal of Geology, volume 16, pages 159-190. Part II, Relation of sediments to regions of deposi- tion. Ibid., pages 255-295. Part III, Relations of climate to stream transportation. Ibid., pages 363-384. Abstracts in Science, new series, volume 25, 1907, page 766; and Bulletin of the Geological Society of America, volume 18, 1906, pages 616-621. Some distinctions between marine and terrestrial conglomerates. Relative importance of continental, littoral, and marine sedimentation. Jour. Geol., vol. 14, 1906, pp. 316-356, 430-457, 524-568. a8 PROCEEDINGS OF THE ANN ARBOR MEETING Barrell, after recognizing that the characteristics of certain important geologic formations were not compatible with what was known of the features of marine sediments, undertook a comprehensive study of the characteristics of continental and littoral deposits, the only other classes of deposits to which they could belong. He worked mostly by compila- tion from literature and by deduction from well established principles, hut he made a few simple experiments on the formation of mud-ceracks. In many respects his work was not so detailed as desirable. For instance, he gave no mechanical analyses of the sediments studied, sorting is dis- cussed in only a general way, and more attention might profitably have been paid to the mineralogic and chemical composition of sediments. He himself recognized and mentioned these deficiencies, thereby offering guidance to further studies in many of the important problems in sedi- mentation. It is practicable in a brief review, such as this necessarily is, merely to indicate some of the important results of Barrell’s studies, and it should be stated in fairness to others that many others had prior to Barrell done more or less work along similar lines; but to him belongs the credit of assembling scattered observations and conclusions, organizing them into a consistent body of usable criteria, and applying these criteria to the interpretation of many formations. Certain factors in the control of sedimentation and certain distinctive features of some kinds of sediments will be briefly discussed, the remarks being based on his principal articles. Reviews by him and his discussions of papers by others are not consid- ered, because to do so would unluly extend the length of this statement. THE RELIEF FACTOR IN. DEPOSITION A concept of fundamental importance in the consideration of problems of sedimentation is that of baselevel. That there is a terrestrial base- level, the goal toward which all erosional agencies on the land are work- ing,.and that there is a marine baselevel, which is effective wave base, toward which marine agencies are working, have long been recognized, but they had not been sufficiently considered in their relations one to the other. Barrell says: “Thus sediments whose interpretation from [sic] the basis of earth history have been characteristically deposited with respect to a nearly horizontal con- trolling surface. This surface of control is baselevel, but for continents and marine deposits the baselevel is determined by different agencies and is a word of more inclusive content than the sense in which it has generally been used by physiographers as a level limiting the depth of filuviatile erosion. Sedimentation as Well as erosion is controlled by baselevel, and baselevel, local WORK OF JOSEPH BARRELL ON SEDIMENTATION 33 or regional, is that surface toward which the external forces strive, the sur- face at which neither erosion nor sedimentation takes place.” ° Any change in the surface of the lithosphere that causes a change in the position of the land surface or of the sea-bottom with reference to baselevel will obviously produce corresponding changes in sedimentation. Barrell states a principle accepted by most geologists, although he con- sidered it desirable to present the evidence on which it is based, as follows: “The rate of denudation increases through the stage of topographic youth, reaching a maximum when all of a drainage basin has become dissected and given a maximum of sloping surface. From this mature stage the rate de- creases as the elevation of the interstream areas are lowered, and finally nearly ceases in topographic old age.” ‘ Firmly grasping this principle, the characteristics of continental de- posits are discussed.* He classifies these as follows: “Formations made upon the land may be classified under several divisions, as follows: “Desert deposits.—Typically where the evaporation exceeds the precipita- tion and no outflowing drainage results. “Piedmont river deposits—-Built up by rivers or shallow lakes upon the foreland plains or piedmont belt fronting high mountain ranges. “Basin deposits of pluvial climates.—The deposits laid down by rivers or in lakes in down-warped basins, such as those of the Great Lakes, situated in continental interiors, but not necessarily associated with mountains. If a large river, laden with sediment, flows across such a region, a lake condition can hardly arise, but, on the contrary, a broad river plain is more likely to be found, constantly built up as subsidence takes place. “Subaerial delta deposits—Where powerful and sediment-laden rivers meet the sea, especially if the latter is shallow and protected from tides and storms, a delta is rapidly developed, a considerable portion of which is a land surface reclaimed by the river from the sea.’ Each of these classes of deposits is discussed with reference to its stage in the physiographic cycle, but the conclusions can not be summarized in this place. The effect of both orogenic and epeiric crustal movement on sedimenta- tion are discussed in considerable detail, particularly in his “rhythms ®Rhythms and the measurements of geologic time. Bull. Geol. Soc. Am., vol. 28. TON. py 708. TOp. sup. cit., p. 756. § Illustrative quotations are not in chronologic order, for it can be inferred from Barrell’s writings that conclusions had been definitely reached and were being utilized by him before he actually expressed them in the words best adapted for purposes of quotation. * Relative geological importance of continental, littoral, and marine sedimentation. Jour. Geol., vol. 14, 1906, pp. 328, 329. ITI—BuLL. GEOL. Soc. AM., VoL. 34, 1922 34 PROCEEDINGS OF THE ANN ARBOR MEETING and the measurements of geologic time,” pages 753-809, where it is con- vincingly shown that because of tectonic movements in late Tertiary and Pleistocene time and the consequent high stand and great relief of the continents, the rate of erosion, and correlatively the rate of sedimenta- tion, far exceeds the average rate of erosion and sedimentation of earlier geologic time, “ten or fifteen times the rate for all of geologic time since . the opening of the Paleozoic.” Under the caption “Rate of sedimentation determined by subsi- dence,’ ?° Barrell emphasizes a geologic relation that deserves noting. In connection with the recognition of the control of baselevel over both erosion and deposition, it is stated that ‘‘on the surface of deltas or the floors of epeiric seas sedimentation records the rate of subsidence, not the rate nor the amount of denudation.” The subsidence in general is not due to the load of sediments. “It may readily be granted that this load of sediment, acting in the same direction as the forces initiating subsidence, would tend to continue it and carry it to greater depths; but without the sediments, deep water would almost surely have resulted. such as exists at present in the southern part of the Gulf of California. a geosyncline filled only at its northern end.” THE CLIMATIC FACTOR IN DEPOSITION One of Barrell’s longest papers on problems of sedimentation is en- titled “Relations between climate and terrestrial deposits.’ In the gen- eral introduction to this series of articles he says: “The environment of the lands may be classified into three fundamental and independent factors—the relations to the surrounding seas, the topography which forms their surfaces, and the climates which envelop them—each of major importance in controlling the character of the lands and the evolution of their inhabitants. “The third great problem of terrestrial environment, the succession of ancient climates, lags still farther behind in development, but is no less important in a complete understanding of the history of the earth and its inhabitants. This lack of development is doubtless due to the intangible nature of climate and the absence of direct record of its geologic changes. When it is considered, however, how fundamental are the relations of continental deposits to the climates in which they are formed, it is seen that the record of geologic eli- mates, while indirect and largely awaiting interpretation, is nevertheless in existence. 1 Rhythms and the measurements of geologic time. Bull. Geol. Soe. Am., vol. 28, 1917, pp. 785-789. 11 Jour. Geol., vol. 16, 1908, pp. 159-190, 255-295. 363-384. WORK OF JOSEPH BARRELL ON SEDIMENTATION 3D ee . climate is a factor comparable to disturbances of the crust or move- ments of the shoreline in determining the nature and the variations in the stratified rocks of continental or offshore origin, thus playing a part of large, though but little-appreciated, importance in the making of the stratigraphic record.” As it is quite impracticable to summarize in this place this excellent study, only the divisions of the subjects will be given and a few general remarks made. Part I is entitled “Relations of sediments to regions of erosion,” and in it are discussed the “character of rocks supplying sedi- ment,” “relations of rainfall and topography to erosion,” “relations of temperature and topography to erosion,” “separation of the topographic and climatic factors,” and “separation of tectonic and climatic oscilla- tions.” Part II is entitled “Relations of sediments to regions of deposi- tion,” and in it are considered the “influence of nature of surface of deposition” (piedmont slopes and aerial deltas, lower floodplains and aqueous deltas, and criteria for the elimination of local geographic fac- tors), and the “climatic influences in regions of deposition.” Under the latter caption attention is paid to the effects of constantly rainy climates, intermittently rainy climates, semi-arid climates, and arid climates, and to the climatic significance of color. Part III is devoted to the “Relations of climate to stream transportation.” In this part the topics discussed are “the effects of stream transportation,” “relations of stable climates to transportation,” and “effects of varying climates upon transportation.” These topics can only give an idea of the treatment of the subject. One chmatic relation of special importance will be mentioned. Barrell describes in the third part of this article how the piedmont slopes built up in the youth of a normal topographic cycle would be trenched and the remoyal of the component materials commence in a stage of maturity. If there were in topographic maturity a sudden change from semi-arid to pluvial climate, erosion of the piedmont slopes will be accelerated and “the final region of deposit undergo a sudden increase in sedimentation, which may be called a veritable flood of waste, but it will be of phenom- enal coarseness compared to that which preceded and that which will come after.” 1” Conglomerates and sandstones are classified into marine. tectonic, and climatic. He says: “Climatic conglomerates and sandstones are here made distinct and inde- pendent from those of tectonic origin by the taxonomic elevation of the shift- img location of deposits (in space) to coordinate importance with intermitten? uplift and resulting pulses of erosion (in time). * PAO Clive OD: OF L; otc. Hee Clits, Ds ose 36 PROCEEDINGS OF THE ANN ARBOR MEETING RESTORATION OF THE FORMER LIMITS OF GREATLY ERODED FORMATIONS There has been a tendency among paleogeographers to draw the orig- inal boundaries of geologic formations not far from the present limiting outcrops. Because of the existence of detached outliers and because of the evidence of the superposition of drainage lines, as Davis showed to be the case in New Jersey, the original boundaries of some formations have been indicated as lying some distance from the present outcrops of the main bodies of the formations. Barrell in his paper, “The Upper Devonian delta of the Appalachian geosyncline,” presented additional criteria for ascertaining the approximate limits of formations that have undergone great erosion. One section of this article is devoted to show- ing that, except on the borders of fault troughs, there is no necessary structural relation between the present and the original limits of forma- tions, therein taking issue with Willis’s opinion on initial dips and the original limits of formations. The additional criteria adduced by Barrell are derived from the character of the sediments of the marginal outcrops and the rate of thinning at the present margins. If continental clastic sediments show by the rounding of pebbles and by gradual reduction in size of pebbles away from the source of the constituents, thereby indicat- ing transportation for long distances, it is obvious that the original mar- gin of the formation lay nearer the source of supply of the sediments than does that part of it still preserved. Deductions from rate of thinning of sediments as to the position of the original boundary rest upon the as- sumption that “the thinning shown near the present margin continued uniformly to original limits—an assumption which certainly is not ex- actly true, but which on the other hand serves as an approximation.” THE SIGNIFICANCE OF SOME SPECIAL FEATURES OF SEDIMENTS Barrell repeatedly emphasized that really sound conclusions on the origin and conditions of deposition of sediments should result not from a single line of evidence, but from the convergence of several independent lines. However, a few special features of importance in interpreting continental deposits will be mentioned. The most favorable conditions for the formation and preservation of mud-cracks are undoubtedly floodplains that are subjected to periodic overflow and on which are made deposits of non-calcareous clay alternat- ing with somewhat coarser material. Although Barrell gave his first comprehensive discussion of the significance of mud-cracks in 1806,14 the subject is brought up again and again in his later papers. He says: 1*# Relative geological importance of continental, littoral, and marine sedimentation. Jour. Geol., vol. 14, 1906, pp. 524-568. WORK OF JOSEPH BARRELL ON SEDIMENTATION oi “It would seem that next to coal beds formed in situ, or abundance of land fossils belonging to the animal kingdom, that mud-cracks form one of the surest indications of the continental origin of argillaceous deposits.” ” The significance of mud-cracks, and also of rain-prints and rootmarks, is entirely convincing when developed, both broadly and vertically through mechanical sediments.” *° From a study of the conditions most favorable for the production of thick conglomerate formations,’ Barrell concluded that continental con- glomerates exceeded marine conglomerates in importance. He says: “A maximum limit to widespread basal marine conglomerates seems to be 100 feet, and therefore broad conglomerate formations of greater thickness are evidence of terrestrial accumulation.” * Minor features indicating marine or river action is pointed out. For instance, he says: “W. D. Johnson pointed out that in the Tertiary deposits of the High Plains the gravel courses, where exposed to observation, are greatly elongated in the direction of the streams—that is, in the direction leading away from the source of supply. Mansfield has noted that shore gravels, on the contrary, are ex- tended in courses parallel to the margin of the deposit.” He also says: “River gravels are shingled by the currents, so that the longer diameter of the pebbles dip upstream, giving a faint appearance of false bedding, which on the average, unlike the false bedding of sandstone strata, dip toward the basin margin. Shore gravels, on the other hand, are developed parallel to the shore. The onshore waves have a greater force than the undertow and the shingling dips away from the shore, or runs out laterally from protruding headlands.” * The color of rocks, particularly with reference to the continental de- posits, was discussed in considerable detail by Barrell. He says: “Such a relation of red shales and gray or green sandstones may then be taken as presumptive evidence of subaerial deposition. It should not, how- ever, be taken by itself as positive evidence, as the number of cases studied on which the conclusion rests is still somewhat limited.” And regarding lateral and vertical variegations in clays, he says: “Such variegated beds are then highly suggestive of terrestrial deposition, 15 Op. sup. cit., p. 550. 16 Am. Jour. Sci. (4), vol. 36, 1914, p. 438. 17 Some distinctions between Marine and terrestrial conglomerates. (Abstract.) Sci- ence, n. s., vol. 29, p. 624; Bull. Geol. Soc. Am., vol. 20, 1910, p. 620. 183 Am. Jour. Sci. (4), vol. 36, 1914, pp. 489, 440. 19 Bull. Geol. Soc. Am., vol. 27, 1916, p. 357. 38 PROCEEDINGS OF THE ANN ARBOR MEETING and indicate, furthermore, a large development of Swamp and pond conditions under a normally humid climatic condition.” *° One thesis in regard to the red color of some rocks defended by Barrell will be noted. He says regarding ferric oxide, to which the red color of sedimentary rocks is due: “Spontaneous dehydration, assisted by heat and favored by time, does not appear, however, to be the sole cause of the great contrast in color between the consolidated and the surfical ferruginous sediments. A still more potent cause exists in the dehydration effected by the great increase in pressure and mod- erate rise in temperature which take place upon the burial of the material to some thousands of feet beneath later accumulations.” * The presence of feldspar particles in sediments that have been trans- ported considerable distances is advanced as evidence of a semi-arid cli- mate, for it “indicates a notable degree of physical, as contrasted to chemical, weathering in the regions of erosion.” ?? This criterion is a decidedly valuable one. He says: “An examination of the character of the matrix or associated fine beds is of importance in determining the climatic conditions attending the origin of a terrestrial conglomerate or sandstone. . . . The character of this fine fluvia- tile or wash detritus in the region of its origin may, therefore, be taken as an index of climate. The size or abundance of the coarser.material, on the other ~hand, forms a measure of the rapidity of erosion, and roughly of the degree of topographic relief.” * : As a part of Barrell’s studies of the value of criteria, it will be noted that he dissented from certain of Grabau’s opinions regarding the value of overlaps. He says: “From these examples it is seen that overlap away from the source of supply can not be used as a criterion of continental or marine origin, any more than transgressive or regressive overlap, but may be due to regional subsidence or tilting or a climatic change which shifts clastic material of a certain kind progressively farther from the source of supply.” * THE INTERPRETATION OF PARTICULAR GEOLOGIC FORMATIONS Barrell worked from the concrete to the abstract and from the abstract to the concrete. He began by the consideration of specific phenomena. * Bull. Geol. Soc. Am., vol. 238, 1912, pp. 422, 428. 21 Jour. Geol., vol. 16, 1908, p. 288. = Origin and significance of the Mauch Chunk shale. Bull. Geol. Soc. Am., vol. 18, 1907, p. 470. *3 Jour. Geol., vol. 16, 1908, p. 182. ** Criteria for the recognition of ancient delta deposits. Bull. Geol. Soc. Am., vol. 23, 1912, p. 395. WORK OF JOSEPH BARRELL ON SEDIMENTATION 39 For the interpretation of these he sought similar phenomena which were produced under known conditions, and knowledge of fundamental prin- ciples, and he then returned to the problem that he at first had in mind. Barrell’s investigations of a few formations will be briefly reviewed. In his first lengthy paper, under the caption “Illustrative geological application,” ?° he discussed the mud-cracked geologic formations of the Precambrian of Montana and Arizona and concluded that considerable portions of the Belt terrane and the Grand Canyon series are continental deposits. The Gila conglomerate of Arizona*® was considered by Barrell as pos- sibly due to climatic causes, for “An examination of the literature showed that the relations of the two divisions of the Gila conglomerate, the vol- umes and relative ages of each, corresponded with the two epochs of glaciation which were pronounced in Utah and Nevada and the two periods of expansion of Lakes Bonneville and Lahontan.” It appears to have “originated from an increase in the ratio of erosion to transporta- tion, due to the severe cold and consequent frost action of the Glacial times, without a correspondingly large increase, in this arid region, of precipitation.” The origin of the “Orange Sand” formation of Hilgard or the “Lafay- ette” formation of Hilgard and McGee is discussed and the hypothesis is advanced that it may be due to a climatic cause, by a shift from a semi- arid to a rainy climate, as had been indicated on preceding pages of this review." The Mauch Chunk shale, for the interpretation of which the studies recorded in the article above referred to were made, “in the anthracite region, more surely in the southeastern and eastern portions,” is shown to be, from top to bottom, “a subaerial delta deposit laid down under a semi-arid climate.** The Patuxent, Arundel, Patapsco, and Raritan formations of the At- lantic Coastal Plain are interpreted as deltas which “were confluent as a flat piedmont coastal plain, probably with a highly irregular and shifting shoreline.” ?° Barrell’s most extensive studies of any set of formations were those of “The Upper Devonian delta of the Appalachian geosyncline,” *° and 75 Jour. Geol.. vol. 14. 1906, pp. 353-568. 76 Jour. Geol., vol. 16, 1908, pp. 173-174. 77 Op. sup. cit., pp. 373-378. * Bull. Geol. Soc. Am., vol. 18, 1907, p. 450. * Bull. Geol. Soc. Am., vol. 23, 1912. p. 410. % Am. Jour. Sci. (4), vol. 36, 1913. pp. 429-472; vol. 37. 1914, pp. 87-109, 225-253. 40 PROCEEDINGS OF THE ANN ARBOR MEETING these represent the climax of his interpretative researches on sedimentary formations. Nearly all of his antecedent work on sediments led up to this masterpiece, and out of it grew another masterpiece, his papers bear- ing the general title “Strength of the earth’s crust.” *t He says regard- ing the Upper Devonian delta: “The Portage and Chemung are seen to be the shallow sea equivalents of the Oneonta and Catskill, a subaqueous top set plain. The Skunnemunk con- glomerate is a down-folded remnant of a piedmont alluvial gravel plain which lay between the flat delta surface and the mountains. The Pocono sandstone, into which the Catskill passes by transition, is seen to be divided into two phases—a marine phase in western Pennsylvania and Ohio, a fluviatile phase in eastern Pennsylvania. In the Pocono the sharp delimitation of the two phases is obscure, but between the Catskill and Chemung the color contrast draws the dividing line separating the subaerial and subaqueous topset beds. The margin of the delta no doubt held lagoons varying from brackish to fresh water, so that marine fossils should be somewhat more restricted in their range than the gray and olive shales.” ” “The red shale formations, the Catskill and the Mauch Chunk, show transi- tions on the east into the overlying formations. The Pocono, on the contrary, passes abruptly at its top into the Mauch Chunk shale. Both the Pocono and Pottsville conglomerates are made up dominantly of much water-worn white quartz pebbles, and their whole areas are characterized by a great dominance of siliceous over argillaceous contents. All of these features correspond to the theoretic results upon a broad piedmont slope of increasingly wide swings of the climatic pendulum which carried the world from Upper Devonian warmth and semi-aridity to Upper Carboniferous humidity and possible cool- ness." = As regards the former extent of the Upper Devonian delta deposits and the source of the material composing them, Barrell says: “The margins of the gravel plain may therefore be estimated at perhaps from 20 to 35 miles to the southeast of the Green Pond syncline, making the original limits of the Upper Devonian deposits from 45 to 60 miles southeast of the present outcrops in Pennsylvania. . . . The distance to the north- western edge of the crystalline floor concealed beneath the Coastal Plain is now about 65 miles, and from beyond this line it would appear that the greater portion of the quartzite must have been derived.” The site of the source of most of the sediments forming the Upper Devonian delta is now the Atlantic Continental Shelf, or even farther seaward, for a source must have existed for 63,000 cubic miles of material. The Triassic deposits of New Jersey and Connecticut are mentioned in many of Barrell’s papers, and their origin is particularly considered 31 Am. Jour, Sci. (4), vol. 37, 1914, p. 250. See footnote. 32 Am. Jour. Sci. (4), vol. 36, 19138, p. 465. 33 Am. Jour. Sci. (4), vol. 37, 1914, pp. 241, 242. WORK OF JOSEPH BARRELL ON SEDIMENTATION 4] in his “Central Connecticut in the geologic past.” #* His opinion was that the sediments were deposited from the waters of migrating rivers and shifting lakes, and that the sediments of the wide river floodplains were subjected to periodic drying. The climate was inferred to be of semi-arid character. Another group of formations that engaged Barrell’s attention was that known as the Old Red Sandstone in the British Isles, and his last impor- tant paper on the interpretation of geological formations was entitled “Dominantly fluviatile origin under seasonal rainfall of the Old Red Sandstone.” * The conclusions reached in this study are stated as follows: “The central conclusion reached in this paper is that the Old Red Sandstone formations were not deposited in lakes or estuaries, nor are they of desert origin. The analysis of their characteristics and comparison with sediments now forming determine them to be river deposits accumulated in inter- montane basins. This is a kind of sedimentation not now found in the British Isles. For a close analogy one may turn to the basin deposits of the western United States laid down in the Tertiary period between the growing ranges of the Cordillera. This reinterpretation of the Old Red Sandstone of the British Isles is in line with that which has gone forward in America during the past fifteen years in regard to the origin of the continental Tertiary deposits: once looked on as deposited in lakes greater in area than any now existing on the earth, they are now regarded as accumulations made chiefly on river plains. Such a reinterpretation for the Old Red Sandstone involves radical changes in the conception of Devonian geography—no less a change than the substitu- tion of land surfaces, occasionally flooded, as a replacement in the mental vision of wide and permanent bodies of water. If the new interpretation is well founded, it means that such terms as ‘Lake Caledonia’ and ‘Lake Oreadie’ should be turned into ‘Caledonian and Orcadian basins.’ ” * RHYTHMS AND THE MEASUREMENTS OF GEOLOGIC TIME The title of this section of this review is that of the one of Barrell’s papers®’ in which he probably attained his greatest height as thinker on fundamental geological problems. A part of it was presented under the title “The significance of sedimentary rhythms,” as one of a series of papers composing a “Symposium on the interpretation of sedimentary rocks,” at the meeting of the Geological Society of America in Albany, New York, December 29,1916. It is not practicable to give in this place even an adequate review of this remarkable memoir; a few comments and 34 Connecticut State Geological and Natural History Survey, Bull. 23, 1915, pp. 28-32. 35 Bull. Geol. Soc. Am., vol. 27, 1916, pp. 345-386. 36 Op. cit., pp. 348, 349. 37 Bull. Geol. Soc. Am., vol. 28, 1917, pp. 745-904, pls. 43-46. 4? PROCEEDINGS OF THE ANN ARBOR MEETING quotations must suffice. The work should be studied by all interested in the fundamentals of geology. Barrell’s studies of rhythms affecting sedimentation have been indi- cated in the discussions of his researches on the relief factor and climate factor in deposition. The first paragraph in his “Rhythms and the meas- urements of geologic time” is as follows: “Nature vibrates with rhythms, climatic and diastrophic, those finding stratigraphic expression ranging in period from the rapid oscillation of sur- face waters, recorded in ripple-marks, to those long-deferred stirrings of the deep imprisoned titans which have divided earth history into periods and eras. The flight of time is measured by the weaving of compositive rhythms—day and night, calm and storm, summer and winter, birth and death—such as these are sensed in the brief life of man. But the career of the earth recedes into a remoteness against which these letter cycles are as unavailing for the meas- urement of that abyss of time as would be for the measurement of human history the beating of an insect’s wing. We must seek out, then, the nature of those longer rhythms whose very existence was unknown until man by the light of science sought to understand the earth. The larger of these must be measured in terms of the smaller, and the smaller must be measured in terms of years. Sedimentation is controlled by them, and the stratigraphic series constitutes a record, written on tablets of stone, of these lesser and greater waves of change which have pulsed through geologic time.” The paper is divided into six parts, as follows: I, Rhythms in denuda- tion; II, Rhythms in sedimentation; III, Estimates of time based on geologic processes; IV, Measurements of time based on radioactivity; V, The age of the Llano series, Texas; VI, Convergence of evidence on geo- logic time and its bearings. In Part I it is shown that, because of the present relatively high stand of the continents, the rate of denudation is probably far in excess of the average for geologic time—“the present mean rate may be twice the mean for the whole of the Cenozoic and 10 or 15 times the rate for all of geo- logic time since the opening of the Paleozoic.” ** From this it follows ‘that time is far longer than those estimates which have been based on a hypothesis that the present rate is a mean which applies to the geologic page" In Part II particular emphasis is put on breaks in the continuity of deposition. The word disconformity is applied according to current usage, but for cessations of minor magnitude in deposition the term diastem is proposed. The admission of the great importance of lost in- tervals in deposition destroys the basis “for estimating the time of the % Op. cit., p. 776. WORK OF JOSEPH BARRELL ON SEDIMENTATION A3 accumulation of the whole formation by means of an assumed rate of continuous denudation and corresponding sedimentation.” *° In Part III several estimates of geologic time are critically reviewed with reference to “the relations of methods to results and the assumptions on which those methods rest.” Estimates by Lyell, Croll, Kelvin, Sollas, Walcott, Goodchild, Becker, and others are discussed. A fundamental error in many of these estimates lies in the assumption of continuous erosion and continuous deposition at present rates. This assumption invalidates the age estimates by Becker based on the present sodium chloride content of the ocean. These estimates are, therefore, too low. Goodchild’s estimate of 704,000,000 years since the beginning of the Cambrian is considered of the proper order of magnitude. Becker’s esti- mate of the age of the earth from a combination of data based upon the supposed “curve of fusion of diabase with respect to pressure,” the tem- perature gradient of the earth according to increase in depth, data on isostasy, and data on radioactive minerals is severely criticized in these words: “Thus, assumption is built on assumption into a many-storied structure and the whole rests on a foundation of quicksand.” *° Part IV consists of a careful review of the subject of radioactive min- erals in their bearing on the age of the earth. Accumulation of helium, pleochroic halos, and accumulation of lead are discussed in considerable detail. Barrell’s data are taken from Rutheford, Ellen Gleditsch, Arthur Holmes, Ramsay and Soddy, Strutt, Boltwood, and others. The helium ratio indicates an age of 623 to 715 million years as the age of the Lower Precambrian of Renfrew County, Ontario, Canada; but all that this ratio tells is that “the age of a mineral is greater than a certain minimum value.” * The lead ratio indicates an age for the larger helium ratio above given as 1,500 million years. In Part V it is shown that Becker’s conclusions on the uranium min- erals from the pegmatite dikes of the Llano series, Texas, are unjustified, and that after eliminating certain analyses for specific reasons, the others serve “as a reliable means of measuring the age of the Llano series and add their weight to the value of the method.” *? In Part VI the different lines of evidence are brought together and on pages 884 and 885 a new table of geologic time is presented. The begin- ning of Cambrian time is given as between 550 and 700 million years ago; Mesozoic, between 135 and 180 million years ago; Cenozoic, between 39 Op. cit., p. 798. SVOps Cit... Pp: S41. 1 Op. cit., p. 847. 22 Op. cit., p. Sti. 44 PROCEEDINGS OF THE ANN ARBOR MEETING 55 and 65 million years ago. Certain Precambrian formations are as old as 1,400 million years, and before this the earth had a long and com- plicated history. “The depths of geologic time leave us face to face with the unknown.” #8 CONCLUSION Although Barrell worked on several different aspects of geology, there was one fundamental, dominant note in all he did. He was primarily striving at the elucidation of the history of the earth. His early training as an engineer supplied him with an appropriate foundation in mathe- matics, physics, mechanics, and astronomy and impressed upon him the engineer’s aim for quantitative, not merely qualitative, expression. Bar- rell studied sedimentation, but he did not stop with ascertaining the con- ditions under which certain formations were deposited. He undertook on one hand a study of the strength of the earth’s crust, the constitution of the interior of the earth, the age of the earth, and the origin of the earth and the solar system. On the other hand he sought to trace the effects of physical agencies on the evolution of organisms. It was, there- fore, not so much because of this one thing or that one thing that Barrell is preeminent: it was rather because he grasped many things and by his powertul synthetic mind focused them on the great problems of earth history, and made contributions so monumentally important that he justly deserves appraisal as one of the world’s great geologists. MEMORIAL OF JAMES E. TODD? BY FRANK LEVERETT James Edward Todd, one of the charter members of our Society, was born at Clarksfield, Ohio, February 11, 1846. His father, Reverend John Todd, a Congregational minister, took up pioneer work in southwestern Towa in 1850, and it was in these pioneer surroundings that the subject ot our sketch grew up. The nearest store was 20 miles away, and the grist-mill still farther. Hulled corn was long the main diet in his child- hood. Economy and industry were made imperative and habits of ease or indolence were not permitted. His father was one of the founders of Tabor College, at Tabor, Iowa, and it was there that young Todd received his early education. From there he went to Oberlin College, where he graduated in 1867. He then attended Union Theological Seminary in New York, in 1867 to 1869, and returned to Oberlin to obtain the degree 4. Op; cit. 1 Manuscript received by the Secretary of the Society February 2, 1923, BULL. GEOL. SOC. AM. VOL. 34, 1922, PL. 3 MEMORIAL OF J. E. TODD 45 of Bachelor of Divinity in 1870. During the Civil War he served 100 days in 1864 as private in Company K, 150th Ohio Infantry. He was married June 15, 1876, to Miss Lillie Carpenter, of Tabor, Lowa, and is survived by his widow and three sons. The eldest son, Prof. M. E. Todd, is an electrical engineer on the faculty of the University of Minnesota. The second son, E. A. Todd, is a chemist employed in oil plants in Okla- homa. The third son, J. EK. Todd, is treasurer of Robert College, Con- stantinople, Turkey. Although trained for the ministry, Professor Todd devoted his entire life to the teaching and investigation of scientific matters. He used his influence in reconciling science and religion, and by his earnest Christian life, together with his devotion to scientific truth, did much to illustrate the close relation that science and religion have to the true purpose of life. For 21 years, from 1871 to 1892, Professor Todd filled the chair of natural science at Tabor College. In the summer months, beginning in 1881, he was employed as a special assistant and later as assistant geol- ogist on the United States Geological Survey. His field of work was chiefly in the Dakotas, in the studies of the glacial deposits. In 1891 he was employed in the summer months by the Missouri Geological Survey in a study of the Quaternary deposits, and in the summers of the next two seasons he had an assignment on the Minnesota Geological Survey, to study the drift deposits and lake beaches in the northwestern part of that State. In 1893 Professor Todd received appointment as State Geol- ogist of South Dakota and as professor of geology and mineralogy in the University of South Dakota, at Vermilion, South Dakota. These posi- tions were held for ten years, during part of which time he was also act- ing president of the university. From 1902 to 1907 Professor Todd made detailed studies of several quadrangles in South Dakota for the United States Geological Survey, which were the basis for geologic folios pub- lished later. In 1907 he was appointed to the chair of geology at the University of Kansas, and in this position he extended his study of the glacial deposits over the glaciated portion of Kansas. This position was held until 1918, when he was retired with the title of professor emeritus of the university. After his retirement poor health prevented further active field-work, but he kept up an active interest in scientific problems to the time of his death, which took place at Lawrence, Kansas, on Octo- ber 29, 1922. Professor Todd was skillful in drawing and in the use of the camera in the field, as will appear by reference to the illustrations accompanying his reports and scientific papers. He was accurate to a nicety, and re- 46 PROCEEDINGS OF THE ANN ARBOR MEETING fused to make loose generalizations or take matters for granted. In many cases he withheld his acceptance of the results of his fellow-glacialists until he had himself investigated the phenomena. He was especially guarded in giving his sanction to the current view that there have been several stages of glaciation, separated by long interglacial stages. This finds expression 1n his writings by the use of the words “so-called Kansan, so-called Iowan,” etcetera. The opportunity for detailed study of one of the old drifts.in Kansas, however, removed this uncertainty; so that in his later years the Kansan was recognized as a distinctly older drift than the Wisconsin drift, which had been his especial field of study before. While his studies and writings were primarily scientific and educational, he showed a determined purpose to bring out practical results and appli- cations of geology to the needs of the commonwealths he served. This is shown especially in his papers on the building stones, the water sup- plies, and in the several geologic folios. While Professor Todd’s main field of labor was in the Dakotas, his report on the Quaternary of Mis- sourl and an unpublished report on the Quaternary of northeastern Kan- sas represent a fuller study of these districts than has been made by any other geologist. His contributions to Iowa, Nebraska, and Minnesota geology are also important. For 40 years Professor Todd was actively engaged in teaching, and his field investigations and writings represent merely what was done by him outside his main occupation. He brought to the class-room the spirit of investigation and of untiring zeal in the development of scientific knowl- edge, and was held in high esteem by students as well as by his coworkers and fellow-citizens. BIBLIOGRAPHY * On the annual deposit of the Missouri River during the post-Pliocene. Amer- ican Association for the Advancement of Science, Proceedings, volume 26, 1878, pages 286-291. Richthofen’s theory of the loess in the light of the deposits of the Missouri. American Association for the Advancement of Science. Proceedings, vol- ume 27, 1879, pages 251-239, Has Lake Winnipeg discharged through the Minnesota within the last 200 years? American Journal of Science, third series, volume 17, 1879, page 120: Quaternary deposits of western Iowa and eastern Nebraska. Washington Philosophical. Society, Bulletin, volume 4, 1881, pages 120-121. Intermittent wells in Nebraska. American Naturalist, volume 17, 1883, pages 533-534. 2 Publications relating to geology. BIBLIOGRAPHY OF J. E. TODD AT On the geological effects of a varying rotation of the earth. American Nat- uralist, volume 17, 1883, pages 15-20. The possible origin of some osar. Science, volume 3, 1884, page 404. The Missouri Coteau and its moraines. American Association for the Advance- ment of Science, Proceedings, volume 33, 1885, pages 381-393. Quaternary voleanic deposits in Nebraska. Science, volume 7, 1886, page 373. Further notes on a green quartzite from Nebraska. American Geologist, vol- ume 3, 1889, pages 59-60. Hvidence that Lake Cheyenne continued till the Ice Age. American Associa- tion for the Advancement of Science, Proceedings, volume 37, 1889, pages 202-203. Also, American Naturalist, volume 25, 1889, pages 456-457. The terraces of the Missouri. American Association for the Advancement of Science, Proceedings, 1889, pages 203-205. Also, Proceedings of the Iowa Academy of Sciences, 1887-1889, pages 11-12, 1890. The origin of the extra-morainic till. Iowa Academy of Sciences, Proceedings, 1887-1889, pages 12-14, 1890. On the folding of Carboniferous strata in southwestern Iowa. Iowa Academy of Sciences, Proceedings, 1887-1889, pages 58-62, 1890. The lineage of Lake Agassiz. Towa Academy of Sciences, Proceedings, 18S87- 1889, pages 57-58, 1890. Deep well at Lemars, Iowa.’ American Geologist, volume 5, 1890, pages 124-125. Notes on glacial deposits of North and South Dakota. Macfarlane’s Geological Railway Guide, second edition, 1890, pages 253-256. Nebraska. Macfarlane’s Geological Railway Guide, second edition, 1890, pages 293-296. Striz and slickensides at Alton, Illinois. American Association for the Ad- vancement of Science. Proceedings, volume 40, 1891, pages 254-255. Striation of rocks by river ice. American Geologist, volume 9, 1892, pages 396- 400. Also, Iowa Academy of Sciences, Proceedings, volume 1, part 2, 1892, pages 19-20. Voleanic dust from Omaha, Nebraska. American Geologist, volume 10, 1892, pages 295-296. Also, Iowa Academy of Sciences, Proceedings, volume 1, part 2, 1892, page 16. The shore lines of ancient glacial lakes. American Geologist, volume 10, 1892, pages 298-302. Also, Iowa Academy of Sciences, Proceedings, volume 1, part 2, 1892, pages 17-19. Further note on the Loup and Platte rivers. Science, volume 19, 1892, pages 148-149. Pleistocene problems in Missouri. Bulletin of the Geological Society of Amer- ica, volume 5, 1894, pages 531-548. Preliminary report of a ‘reconnaissance in northwestern Minnesota in 1892. Minnesota Geological and Natural History Survey, 21st Annual Report, 1893, pages 68-78. | Preliminary report of a reconnaissance in northwestern Minnesota in 1893. Minnesota Geological and Natural History Survey, 22d Annual Report, 1894, pages 90-96. Sait A preliminary report on the geology of South Dakota. South Dakota Geolog- ical Survey, Bulletin number 1, 1895, pages 1-172. 48 PROCEEDINGS OF THE ANN ARBOR MEETING Inequalities in the old Paleozoic sea bottom. American Geologist, volume 15, 1895, page 64. Recent geological work in- South Dakota. American Geologist, volume 16, 1895, page 202. Interloessial till near Sioux City, Iowa (with H. Foster Bain). Iowa Aecad- emy of Sciences, Proceedings, volume 2, 1895, pages 20-23. The moraines of the Missouri Coteau and their attendant deposits. United States Geological Survey, Buletin number 144, 1896, 71 pages, 21 plates. Quaternary geology of the Higginsville, Missouri, quadrangle. Missouri Geo- logical Survey, volume 9, 1896, pages 54-59. Special edition issued in 1892 in advance of volume 9. Quaternary geology of the Bevier, Missouri, quadrangle. Missouri Geological Survey, volume 9, 1896, pages 37-47. Special edition issued in 1894 in ad- vance of volume 9. Formation of the Quaternary deposits in Missouri. Missouri Geological Sur- vey, volume 10, 1896, pages 114-217, plates 12-22. Loglike concretions and fossil shores. American Geologist, volume 17, 1896, pages 347-349. Voleanic dust in southwestern Nebraska and in South Dakota. Science, new series, volume 5, 1897, pages 61-62. Is the loess of either lacustrine or semi-marine origin? Science, new series, volume 5, 1897, pages 993-994. A revision of the moraines of Minnesota. American Journal of Science, fourth series, volume 6, 1898, pages 469-477. ) Degradation of the loess. Iowa Academy of Sciences, Proceedings, volume 5, 1898, pages 46-51. First and second biennial reports of State Geologist, with accompanying pa- pers. South Dakota Geological Survey, Bulletin number 2, 1898, 135 pages, 15 plates. The clay and stone resources of South Dakota. Engineering and Mining Jour- nal, volume 66, 1898, page 371. The moraines of southeastern South Dakota and their attendant deposits. United States Geological Survey, Bulletin number 158, 1899, 165 pages, 27 plates, 31 figures. New light on the drift in South Dakota. Iowa Academy of Sciences, Proceed- ings, volume 6, 1899, pages 122-130. Also, American Geologist, volume 25, 1900, pages 96-105. The geology of Hubbard, northwestern Cass, Norman, Polk, Marshall, Roseau, Kittson, and Beltrami counties, Minnesota. Minnesota Geological and Nat- ural History Survey, Final Report, volume 4, 1899, pages 82-155, plates 59-64, figures 9-15. Geology and water resources of a portion of southeastern South Dakota. United States Geological Survey, Water Supply and Irrigation Papers, number 34, 1900, 34 pages, 10 plates. ‘i River action phenomena. Bulletin of the Geological Society of America, yol- ume 12, 1901, pages 486-490. Some problems of the Dakota artesian system. Science, new series, volume 14, 1901, page 794. Also, Scientific American Supplement, volume 52, 1901, page 21504. BIBLIOGRAPHY OF J. E. TODD 49 Moraines and maximum diurnal temperature. Science, new series, volume 14, 1901, pages 794-795. Also, Scientific American Supplement, volume 52, 1901, page 21504. Hydrographic history of South Dakota. Bulletin of the Geological Seciety of America, volume 13, 1902, pages 27-40. Mineral building material, fuels, and waters of South Dakota, with production for 1900. South Dakota Geological Survey, Bulletin number 3, 1902, pages 81-130, 10 plates. Also, Stone, volume 25, 1903, pages 413-418, 521-524. Coneretions and their geologic effects. Bulletin of the Geological Society of America, volume 14, 1903, pages 353-368. Building stones of South Dakota. Stone. volume 26, 1903, pages 20-27. A newly discovered rock at Sioux Falls, South Dakota. Stone, volume 27, 1903, pages 46-48. -Also, American Geologist, volume 33, 1904, pages 35-39. Olivet folio, South Dakota. United States Geological Survey, folio number 96, 1903. ‘Parker folio, South Dakota. United States Geological Survey, folio number 97, 1903. Mitchell folio, South Dakota. United States Geological Survey, folio number 99, 1903. Benton formation in eastern South Dakota. Bulletin of the Geological Society of America, volume 15, 1904, pages 569-575. Geology of Black Hills, South Dakota. American Mining Congress, 6th An- nual Session Report of Proceedings, 1904, pages 51-57. Huron folio, South Dakota. United States Geological Survey, folio number — 113, 1904. Alexandria folio, South Dakota. United States Geological Survey, folio num- ber 100, 1903. Desmet folio, South Dakota. United States Geological Survey, folio number 114, 1904. Geology and water resources of part of the James River Valley, South Da- kota. United States Geological Survey, Water Supply and Irrigation Paper number 90, 1904. : Some variant conclusions in Iowa geology. Iowa Academy of Sciences, Pro- ceedings, volume 13, 1906, pages 183-186. More light on the origin of the Missouri River loess. Iowa Academy of Sci- ences, Proceedings, volume 13, 1906, pages 187-194. Recent alluvial changes in southwestern Iowa. Iowa Academy of Sciences, Proceedings, volume 14, 1907, pages 257-266. Effects of certain characteristics of rocks on their erosion. Iowa Academy of Sciences, Proceedings, volume 14, 1907, pages 267-270. The Elk Point folio. United States Geological Survey, folio number 156, 1908. The Aberdeen-Redfield district, South Dakota. United States Geological Sur- vey, folio number 165, 1909. Drainage of the Kansas ice-sheet. Kansas Academy of Sciences, Transactions, volume 22, 1909, pages 107-112. Preliminary report on the geology of the northwest central portion of South Dakota, with report of State Geologist for 1908. South Dakota Geolog- ical Survey, Bulletin number 4, 1910, 207 pages, 31 plates. IV—BULL. GEOL. Soc. AM., VoL. 34, 1922 50 PROCEEDINGS OF THE ANN ARBOR MEETING A speculation in crystallography. Science, new series, volume 32, 1910, pages 216-218. The fossil fields of Wyoming (with other authors); reports by members of the Union Pacific Expedition. Issued by Union Pacific Railroad Com- pany, 1909, 61 pages. Is the Dakota formation Upper or Lower Cretaceous? Kansas Academy of Sciences, Transactions, volume 23, 1911, pages 65-69. History of Wakarusa Creek, Kansas. Kansas Academy of Sciences, Transac- tions, volume 23, 1911, pages 211-218. Evidences of Pleistocene crustal movements in the Mississippi Valley. Science. new series, volume 33, 1911, page 466. Kansas University Scientific Bul- letin, volume 6, 1912, pages 375-379. Pre-Wisconsin channels in southeastern South Dakota and northeastern Ne- braska. Bulletin of the Geological Society of America, volume 23, 1912. pages 463-470. More about septarian structure. Geological Magazine, decade 5, volume 10, 1913, pages 361-364. The “moraines” of Kansas. Science, new series, volume 37, 1913, page 457. Traces of an early Wisconsin flood. Science, new series, volume 37, 1913, page 457. The Pleistocene history of the Missouri River. Science. new series, volume 39. 1914, pages 263-274. A mnemonic couplet for geologic periods. Science, new series, volume 42, 1915, page 908. Kansas during the Ice Age. Kansas Academy of Sciences, Transactions. vol- ume 28, 1918, pages 33-47. History of Kaw Lake, Kansas. Kansas Academy of Sciences, Transactions. volume 28, 1918, pages 188-199. EKolian loess. Kansas Academy of Sciences. Transactions. volume 28, 1918. pages 200-203. Certain diverse interpretations of Pleistocene in the Dakotas. Bulletin of the Geological Society of America, volume 31, 1920, pages 134-135. Report on the Quaternary formations of northeastern Kansas, prepared for the Kansas Geological Survey (unpublished). Is the channel of the Missouri River through North Dakota of Tertiary ori- gin? Bulletin of the Geological Society of America, volume 33, 1922, page 120. Nore.—NSince the above bibliography was sent to the printer, Dr. C. R. Keyes has published a bibliography of Professor Todd’s geological publications in the February, 1923, number of the Pan-American Geologist, which contains a list of some of the earliest papers by Professor Todd, that appeared as brief ab- stracts in the earliest publication of the Iowa Academy of Sciences. It was issued in 1880, but includes papers presented at meetings of the Academy from 1875 to 1880. The abstracts are found on pages 14-21 of this publication, and embrace the following titles: Remains of elephant found near Glenwood, Iowa. Proceedings of the Iowa Academy of Sciences, 1875-1880; 1880, page 14. MEMORIAL OF LEVI HOLBROOK oA. Recent wind action upon loess. Proceedings of the Iowa Academy of Sciences, 1875-1880; 1880, page 21. Charcoal streak in loess. Proceedings of the Iowa Academy of Sciences, 1875- 1880; 1880, page 21. Roots and root-marks found in loess. Proceedings of the Towa Academy of ; Sciences, 1875-1880; 1880, page 17. Relation of loess to drift in southwestern Iowa. Proceedings of the Iowa Academy of Sciences, 1875-1880; 1880, page 19. Certain changes of Platte River during the Quaternary. Proceedings of the Towa Academy of Sciences, 1880, page 20. Notes on geology of northwestern Iowa. Proceedings of the Iowa Academy of Sciences, volume 1, part 2, 1892, pages 13-16. Voleanic ash bed near Omaha. American Geologist. volume 15, 1895, page 130. Glacial diversion of Missouri River. Pan-American Geologist, volume 39, 1923. (In press. ) Doctor Keyes also states that Professor Todd submitted a paper to him for publication in the Pan-American Geologist, only a few weeks before his death, on the subject “Glacial diversion of the Missouri River” that will appear in an early number of that periodical. MEMORIAL OF LEVI HOLBROOK + BY JAMES F. KEMP The death of Levi Holbrook at his summer home, Center Harbor, New Hampshire, July 26, 1922, diminished by one the already small number of surviving “Original Fellows” of the Society. Starting with ninety- eight in 1889, the group is now twenty-nine. Mr. Holbrook had reached the advanced age of eighty-six years, and, with snow-white hair and beard, had long been one of the striking figures at the meetings of the American Institute of Mining Engineers and those of the American Geographical Society. Levi Holbrook was born in Marlboro, Massachusetts, March 7, 1836, and was the son of Levi and Eliza (Grant) Holbrook. He traced his ancestry to John Holebrook, of Weymouth, Massachusetts, a prominent figure in the early colonial days. Levi Holbrook fitted for college at the Williston Seminary, Kast Hampton, Massachusetts, graduating in 1852. A year later he entered Yale and was valedictorian of the Class of ’57 and member of Phi Beta Kappa. Some trouble with his eyes called for medical care in Boston for the next six months and led to a horseback journey across the Rocky Mountains to the Columbia River and _ back. At this time literary ambitions governed Mr. Holbrook and led him to study modern literature and languages at Cambridge, Massachusetts. 1 Manuscript received by the Secretary of the Society February 10, 1923. 52 PROCEEDINGS OF THE ANN ARBOR MEETING from 1860-63. He was finally compelled to give over these ambitions and entered business life in Boston, moving in 1871 to New York, where he made his home the rest of his hfe. He employed himself but part time in business and reserved for various scientific and learned societies his leisure and his energies. He was president for a time of the Phi Beta Kappa alumni, resident in New York; was councilor and secretary of the American Geographical Society, and became one of the Original Fel- lows of the Geological Society of America, among whose organizing com- mittee of five Charles H. Hitchcock was his old classmate at the Williston Seminary and his hfelong friend. Mr. Holbrook joined the American Institute of Mining Engineers in 878 and was one of its managers from 1895-97. The famous secretary of the Institute for many creative years, the late Rossiter W. Raymond, was one of his intimates, and in the Institute and the Century Society the writer came to be numbered among his good friends nearly twenty- five years ago. Mr. Holbrook took a warm interest in patriotic societies. He was a member of the Society of Colonial Wars and of the Sons of the Revolution. For some time he served as registrar-general of the Order of Founders and Patriots of America. He was also a member of the New England Genealogical and Historical Society and of the American Fine Arts Society. Mr. Holbrook thus never followed geology as a profession, but was deeply interested in its progress and a warm supporter of its interests. He was a lover of the world of nature and turned often to travel and enjoyment amid mountains and inspiring scenery. Mr. Holbrook was married December 27, 1871, to Viola Vowers, and he and Mrs. Holbrook had the rare experience of celebrating their fiftieth wedding anniversary in 1921. Mrs. Holbrook followed her husband a few weeks after his death. A son, Clark Holbrook, of Red Bank, New Jersey, and a daughter, Helen, now Mrs. Julian P. Smith, of Upper Montclair, New Jersey, survive their parents. ADDRESS OF THE RETIRING PRESIDENT The address of the retiring President, Charles Schuchert, on “Sites and nature of the North American geosynclines,” was then presented. Since this paper is a part of the “Symposium on the structure and his- tory of mountains and the causes of their development,” it has been held for publication with that series of papers. With this paper, and after a few announcements of changes in program and directions for local guidance were made by the Secretary, the morn- ing session of the Society ended. ABSTRACTS OF PAPERS Be —~ SESSION OF THURSDAY AFTERNOON The afternoon session was opened at 2.15 o'clock, with President Schu- chert in the chair. The object of the symposium announced for this session was briefly reviewed by the chairman, who called attention to the fact that the presidential address given in the morning session is properly a part of this “Symposium on the structure and history of mountains and the causes of their development.” TITLES OF PAPERS PRESENTED SYMPOSIUM ON THE STRUCTURE AND HISTORY OF MOUNTAINS AND TIE CAUSES OF THEIR DEVELOPMENT SITES AND NATURE OF THE NORTH AMERICAN GEOSYNCLINES PRESIDENTIAL ADDRESS BY CHARLES SCHUCHERT THE THHORY OF MOUNTAIN STRUCTURE RECENTLY SET FORTH BY PROFESSOR KOBER OF VIENNA BY CHESTER R. LONGWELL * Presented in full extemporaneously. ASTATIC ARCS BY WILLIAM H. HOBBS Presented in full extemporaneously. THH APPALACHIANS BY ARTHUR KEITH Presented in full from notes. HASTERN APPALACHIANS IN THE LATITUDE OF SOUTHERN NEW ENGLAND BY J. B. WOODWORTH Read by title. COAST RANGES AND SIERRA NEVADAS BY BAILEY WILLIS Presented in full extemporaneously. ROCKY MOUNTAINS OF IDAHO AND MONTANA BY G. R. MANSFIELD Presented in full from notes. 1 Introduced by Charles Schuchert. 54 PROCEEDINGS OF THE ANN ARBOR MEETING FRONT RANGES OF COLORADO AND NEW MEXICO BY WILLIS T. LEE Read in full. The papers comprising the symposium as listed above, including the discussions, together with the presidential address of the retiring Presi- dent, Charles Schuchert, will be printed in full in a subsequent number of the Bulletin. The session adjourned at 4.50 o'clock. SESSION OF THURSDAY EVENING DIVISION OF GEOLOGY AND GEOGRAPHY, NATIONAL RESEARCH COUNCIL A round-table discussion of “The functions of the Division of Geology and Geography, National Research Council,” was held under the chair- manship of Nevin M. Fenneman, at 7.30 p. m., in the University of Michigan Union. For the purpose of introducing this discussion the chairman had pub- lished in Science, December 1, a nine-column article setting forth the nature of the organization of the Research Council and of the procedure in the Division of Geology and Geography. The discussion on the con- tents of this paper and the general work of the division was opened by David White, followed by T. W. Vaughan, John M. Clarke, Alfred C. Lane, W. H. Hobbs, A. C. Lawson, and others. Speakers pointed out the opportunities for suitable activity by the division and, to some extent, recounted its successful achievements. The import of the discussion was that the Research Council is not an operat- ing concern equipped for and engaged in the conduct of researches, but rather a mode of coordinated effort of the geologists of the United States. For this purpose it affords conveniences, including chairman and office force. It was pointed out that the effect of providing such facilities is not very different from that which would result from the support of a chairman and office at the disposal of active committees of the Geological Society of America. Twenty-two of the twenty-six members of the division are Fellows of the Society. THE SMOKER At 8.30 p.m. a smoker was given by the University of Michigan to the Fellows of the Geological Society of America, the Paleontological _-~— REPORT OF THE AUDITING COMMITTEE 00 Society, the Mineralogical Society of America, the Society of Economic Geologists, the Association of American Geographers, and their friends. This was largely attended and was held in the University of Michigan Union, occupying the entire evening. SESSION OF FripAy Morninc, DECEMBER 29 The morning session was opened at 10 o’clock by President Schuchert, and the report of the Auditing Committee was called for. The following report was read by H. B. Kummel, chairman of the committee: REPORT OF THE AUDITING COMMITTEE DECEMBER 28, 1922. To the Council and Members, Geological Society of America: The committee appointed to audit the Treasurer’s accounts reports as follows: (1) It has verified the statement as to cash on hand by comparison with the bank statements. (2) It has checked the receipts from fellowship fees, income from investments, and miscellaneous items and found them correct. (3) It has not been possible to verify the items listed under Secre- tary’s receipts because of the nature of the items. (4) It has found that all income due on investments during the year has been paid. (5) It has compared vouchers for disbursements with canceled checks and with printed statement of disbursements and found them correct. (6) The securities in the hands of the Treasurer will be checked in Baltimore by Dr. Reid, of the committee, and report made to the Secre- tary. (7) The committee takes pleasure in testifying to the excellent way in which the accounts are kept. Henry B. KumMet, Chairman. Rotuin T. CHAMBERLIN. This report was received and accepted, conditioned on receipt of addi- tional report covering the securities. Harry Fielding Reid, the third member of the committee, was dele- gated to make an examination of the securities of the Society and submit a written report directly to the Secretary, to complete the committee’s duties. 56 PROCEEDINGS OF THE ANN ARBOR MEETING REPORT -ON SECURITIES BY HARRY FIELDING REID List of Securities Texas and Pacific Railway Company first mortgage 5’s, numbers 11915, 20S92. Fairmont and Clarksburg Traction Company first mortgage 5’s, numbers 29, 30. 3 Chicago Railways Company first mortgage 5’s, numbers 20750, 20751, 45871. 2 Southern Bell Telephone Company first mortgage 5’s, numbers M15217, M13218. 2 Consolidation Coal Company first and refunding mortgage 40-year sinking fund 5’s, numbers 11850, 11851. United States Steel Corporation sinking fund gold coupon 5's, humbers 2964, 2974, 2975. American Agricultural Chemical Company first mortgage 5’s, numbers 5834, 6356. 1 Florida Central and Peninsula Est. 6s, number 2978. 1 Louisville and Nashville Railroad Company 10-year 7 per cent note. number M3941. 1 Bell Telephone Company of Pennsylvania 25-year first and refunding T per cent, number M12813. 1 Braden Copper Mines, number 4391. 1 Edison Commonwealth Company, number 49652. 10 shares Iowa Apartment House stock. 40 shares Ontario Apartment House stock. lo bo wy i) I certify that the securities in the above list are in the possession of the Treasurer of the Geological Society of America, Dr. Edward B. Mathews. Harry Frevpine Rein. BaLTIMorE, February 10, 1923. The report of the Council, which had been laid on the table pending the findings of the Auditing Committee, was then taken up and approved. There being no further business at this time beyond announcements of the Secretary with regard to the handling of transportation certificates, the group photograph, and disposition of the sectional meetings and the meetings of affiliated societies, the scientific program was taken up. TITLES AND ABSTRACTS OF PAPERS AND DISCUSSIONS THEREON, PRESENTED BEFORE THE MORNING SESSION . RECENT WORK IN FRANCE AND SWITZERLAND ON THE STRUCTURE OF THE ALPS BY EMMANUEL DE MARGERIE Presented in abstract from notes. ABSTRACTS OF PAPERS vi A LAYMAN’S VIEW OF THE THEORY OF ISOSTASY BY ¢. K) ERITH (Abstract) An attempt to discriminate the known facts of isostasy from, the various assumptions which have entered into the theory as now known, and a discus- sion of some of these assumptions from the standpoint of structural geology. Read from manuscript. DISCUSSION Mr. D. F. Hieeins: Geologists should not confuse the terms “stress” and “Strain.” In the engineering (physical) sense, stress is a force, strain is a change of shape. To avoid the ambiguity in the word strain, it is better to avoid it altogether and use the word deformation in its stead. As far as the Rocky Mountain Front Range of Colorado is concerned. Pro- fessor Leith’s statement that the hearts of the great ranges are granitic does not hold. The Front Range is essentially sedimentary (Precambrian), into which have been intruded the relatively small granite batholiths of Long's Peak to Pike’s Peak, for example. The assumption of a primordial earth of uniform (initial) density is not in accord with the postulates of the Planetesimal Hypothesis. The Fellows of. this Society know how the differences of density. established by competent geodetic observations, may be invoked at present to bring about, in part at least, the changes of elevation necessary for the erosional cycle, and hence how they may have started the isostatic-erosional cycle at first. The postulation of an earth of initial uniform density, subject only to stresses due to contrac- tion on loss of heat, would not lead to any but very slight deformation due to the fact of isostatic adjustment. Mr. T. P. SHEPARD: Professor Leith’s statement that the mountain ranges are lightened by katamorphism is opposed by the fact that the light katamor- phic material from the mountain ranges is removed by erosion and redeposited on the bordering plains, leaving denser material on the mountains and less dense on the plains. Remarks were made also by Mr. William Bowie. RECTILINEAR SHORELINES OF THE NEW ENGLAND-ACADIAN REGION EY DOUGLAS W. JOHNSON (Abstract) Many rectilinear shorelines bordering parts of New England and Acadia have been attributed to faulting. The paper discusses a yariety of ways in which rectilinear shorelines are produced, and shows that many such coastal lineaments in the region in question, attributed to faulting, are better ex- plained as the result of other processes. Read by title in absence of author. 08 PROCEEDINGS OF THE ANN ARBOR MEETING DYNAMICS OF FAULTING AND FOLDING BY BAILEY WILLIS (Abstract) The direction of forces producing faults is considered and it is shown that faults with a high dip require the action of vertical forces in combination with horizontal forces. When we consider the influence of pressure on the strength of rocks we find that horizontal pressure alone will always produce a fault of dip less than 45 degrees. The forces producing folds are examined, and it is shown that the distribu- tion of folds in the Appalachian region could not have been caused by simple compression, but that forces acting tangentially on the under side of the folded region must have existed. This idea is applied to the elucidation of the results obtained by experiments in folding. An explanation of the nappes of the Alps is suggested. Read by title. CRITERIA FOR THE RECOGNITION OF ACTIVE FAULTS BY STEPHEN TABER Read by title. FAULT WMAP OF CALIFORNIA BY BAILEY WILLIS (Abstract) Fault map of California: description and exhibition of a map of the State, which shows the principal faults at present known. This map has been com- piled from all available data by the Carnegie Institution of Washington, rep- resented by Mr. H. O. Wood, the United States Geological Survey, the Univer- sity of California, Stanford University, and the Seismological Society of Amer- ica, working in cooperation, as a contribution to seismology of the State. Active faults—that is, those on which earthquakes are liable to ocecur—are distinguished from dead faults. The base is the relief map of the State, drawn by J. H. Renshawe, of the United States Geological Survey, which brings out strikingly the relation of the ranges to the active faulting. FAULTS OF THE COAST RANGES OF CALIFORNIA BY BAILEY WILLIS (Abstract) Faults of the Coast Ranges of California; description of the various types of faults recognized in the ranges: upthrusts. overthrusts, progressive thrust- ing, regressive thrusting, transverse thrusts, and normal faults; vertical move- ments of fault blocks involving rotation, protrusion, and depression; horizontal movements; relation of thrusting to folding; antiquity and actual activity of forces; persistence of the structural type: magnitude of the structure; their ABSTRACTS OF PAPERS 59 relation to the sub-Pacific mass: their interpretation as effects of persistent suboceanic spread. These two papers by Bailey Willis were presented together extem- poraneously. DISCUSSION Dr. GeorcE H. ASHLEY: As a result of detailed studies in 1906, 18 terraces were traced on San Pedro Hill, and terraces followed around the ends of the hill, so as to leave no doubt of their terrace character. Again, near San Fran- cisco, on the east side of the San Andrews fault, is a raised block, raised on the west, the Pleistocene deposit sloping to the east from 700 feet above the sea at the fault and passing below the bay on the east. Remarks were also made by Messrs. A. C. Lawson and R. T. Hill, with reply by the author. Author’s reply to Prof. A. C. Lawson: The terraces north of Santa Cruz are correctly described by Professor Lawson as being level, so far as the two lower terraces are concerned. They have been worked over by the sea and exhibit the effects of wave erosion and deposition. The higher terraces are much less well marked, are discontinuous and eroded. I would not like to say categoric- ally that they are or are not level, since individual judgment must enter into the identification of various benches as more or less surely belonging to the same terrace. I agree with Dr. Ashley that the terraces on San Pedro Hill are marine. They are some 400 miles from Santa Cruz. LATE TERTIARY AND QUATERNARY DIASTROPHISM IN SOUTHERN CEBU, : PHILIPPINE ISLANDS BY GEORGE D. LOUDERBACK AND R. R. MORSE (Abstract) The late Tertiary rocks are markedly deformed by faulting, with the pro- duction of hoist and graben forms. Geologic sections will be shown illustrat- ing the character of the faulting and its variation along the strike. The recent diastrophic history is outlined and its effects in the production of faultscarps and marine terraces described. Faulting is believed to be an important process in the production of the island. Presented extemporaneously. PARALLEL FOLDS AND BOUDINAGE BY TERENCE T. QUIRKE (Abstract) Parallel folds die out, both upward and downward, by interference of neigh- boring folds and by the approach of curvature to a straight line. Theoretic- ally, they would die out at infinity, but the folding is almost nothing at a dis- 60 PROCEEDINGS OF THE ANN ARBOR MEETING tance equal to 20 times the diameter of the perfect central fold. Parallel folds represent great shortening along the central axis, which dies out to nothing above and below that axis. It represents a rotational strain with maximum displacement along a plane. The inverse of this fold would be rep- resented by zero shortening along the central plane, increasing to a maximum shortening in both directions from that plane. In this case the folds would not die out from the central axis, but they would increase with distance from the axis. These features are extremely rare, but are represented by the so- called boudinage of southeastern Belgium. The origin of rotational strains which are competent to make boudinage is obscure. Certainly it has no con- nection with normal folding. It is suggested that it represents a _ hitherto unrecognized type of major structure caused by longitudinal compression re- lieved by central bulging. Presented from notes. With this paper the morning session closed at 12.40 o'clock. GROUP PHOTOGRAPH At the close of the morning sessions those of the members in attend- ance who could be assembled on the steps of one of the university build- ings had a group photograph taken. LUNCHEON GIVEN BY THE UNIVERSITY At 1 o’clock members of the Society, together with those of affihated and associated organizations, were entertained at luncheon by the univer- sity in the Michigan Union. ‘ SESSIONS OF FRIDAY AFTERNOON Two sectional meetings, to be held simultaneously, were organized for Friday afternoon. The papers of Group A—dynamical, structural, gla- cial, and physiographic subjects—were presided over by Vice-President Washington as chairman, and Vice-President Robert T. Hill was chair- man of the section in which the papers of Group B, on stratigraphic, paleontologic, areal, and cartographic subjects, were presented. There was also a joint session with the Society of Economic Geologists for the discussion of the ore deposits of the copper-bearing rocks of Michigan. SECTIONAL MEETING OF FRIDAY AFTERNOON FOR GROUP A The section for the reading of papers on dynamical, structural, glacial, and physiographic subjects met at about 2.30 o’clock, in the Auditorium, ABSTRACTS OF PAPERS 6] under the chairmanship of Vice-President Washington and with E. 0. Hovey as Secretary. TITLES AND ABSTRACTS OF PAPERS OF GROUP A AND DISCUSSIONS THEREON CONTRIBUTION TO THE HYPOTHESIS OF MOUNTAIN FORMATION BY E. C. ANDREWS Read by title. EARTH’S CRUST AND ITS EVOLUTION BY REGINALD A. DALY (Abstract) According to records at deep borings, the mean increase of temperature with depth seems to be less rapid in eastern North America than in western and central Europe. In each continent the rate of temperature increase itself in- creases with depth, at least to the depth of 2,000 meters. Deeper down the acceleration doubtless falls to zero and changes sign, but it appears already clear that extrapolation from the average surface gradient is not likely to give a temperature too high at a depth of the order of 40 kilometers. At that depth, therefore, a temperature of 1,200° centigrade or more may be expected. At that temperature and corresponding pressure, ordinary rock-matter can not be crystalline. Angenheister’s recent study of seismograms has led him to estimate the thickness of the crust under the Pacific as about 41 kilometers, and that of the crust under the surface of Eurasia as about 28 kilometers. Thus, from two lines of evidence the conception of a thin, solid crust on a non-crystalline, elastico-viscous substratum seems justified and consonant with the facts of geophysics in general, as well as with a sound cosmogony. That the density of the sub-Pacific crust is greater than the density of the underlying layer is a necessary consequence; hence an important condition for the instability of the crust in past time. These conclusions may guide speculation as to the development of the crust in its present form. Based on the general idea in the Taylor-Wegener hy- pothesis of the horizontal movement of continents, a theory of the continents and ocean-basins will be sketched. This theory includes an explanation of the segregation of the earth’s salic material in one hemisphere; the intense defor- mation of the Precambrian formations; the Postcambrian fragmentation of the primitive continent and the associated mountain-building. Presented extemporaneously. DISCUSSION Prof. W. H. Hosss: As I have listened to Professor Daly’s paper I have thought if he were not such a brilliant geologist what a fine trial lawyer he would be. I have been impressed not with the inadequate attention the Wegener theory has received, but rather with the exaggerated attention that 62 PROCEEDINGS OF THE ANN ARBOR MEETING has been accorded it. It seems to bear a great resemblance to the theory of W. H. Pickering, published a good many years ago in the Journal of Geology. Prof. A. P. CoLEMAN: Professor Daly shows a poetic imagination in his theory of the shifting of continents for thousands of miles, crowding the edges into mountain ranges; but if we admit that isostatic equilibrium is nearly perfect, there must have been a corresponding flow of the underlying plastic stratum for the same distance in the opposite direction. Prof. J. A. UppeEN: I should like to inquire why it is necessary to suppose that there is a glassy zone at certain distance below the crust. To my mind, such a zone is not necessary to permit flowage. Remarks were made also by Messrs. A. C. Lawson, J. L. Rieh, H. M. Ami, and H. 8S. Washington, with reply by the author. OROGENIC EXIGENCIES OF A ROTARY EARTH BY CHARLES KEYES (Abstract) Since the hypothesis of isostasy is really a multiple one and resolves itself into no less than four distinct hypotheses, it becomes obligatory to determine, not from simple mathematical figuring but from calculation and observation in the field, the position of the geological directrix. Assumption of sealevel as a basis is obviously illogical and entirely unsupported by observation ; but the Rocky Mountains in their repeated waxing and waning point to the position of an isostatic datum at about two miles below sealevel as a possible proper basis for calculation. Tsostatic compensation appears to be an orogenic effect and not a cause; and there may be explanations for the same phenomena other than isostasy. : Further experimentation along lines reported several years ago (Bulletin. 30-70, 1919) emphasizes the function of retardation of the earth’s rotation as a primary cause of orogenic disturbance in the globe’s straticulate crust. It does not seem necessary to premise permanency of oceanic basins or of conti- nental plaits. Read by title. ISOSTASY AS A RESULT OF EARTH SHRINKAGE BY FRANCIS PARKER SHEPARD " (.1b0stract) Opposition to the theory of isostasy is directed primarily against geological interpretations of the theory rather than against the geodetic conclusions. Changing these interpretations of the working of isostasy might make it more compatible with the phenomena of geology. Isostasy could be as effective in keeping the crust balanced with a shrinking interior of the earth as with non- shrinking interior. . Mountains due to a shrinking interior would tend to keep 1 Introduced by T. T. Quirke. ABSTRACTS OF PAPERS . 63 in isostatic adjustment. Peneplains and plateaus can be explained without loss of isostatic equilibrium. Periodic diastrophism is opposed to continuous isostasy, but periodic diastrophism is a theory which is based on incomplete field data. Apparent periodicity may indicate only the natural breaks in the evidence of what might be a complete series of diastrophic movements. Such breaks may be caused by the lack of evidence of the stratigraphic data of earth movements, removal of such evidence by erosion or deposition, and by the occurrence of the deformations within the ocean basins. Read by title. FISSILITY OF SHALE: SOME FACTORS CONCERNED IN ITS DEVELOPMENT BY J. VOLNEY LEWIS (Abstract) “Shale” and “shaly’—vague and much-abused terms—are applied even to massive claystone, mudstone, and siltstone, and, with more apparent reason. to rocks of alternate lamination: but this structure is obviously stratification and better designated interlaminate (or interfoliate) shale and sandstone, limestone and claystone, etcetera. Few structures are so little understood as the fissility of homogeneous clays and unsorted muds—their splitting into shelly flakes and wedgelike to splintery fragments approximately parallel to the bedding. It is proposed to restrict the terms shale and shaly to such rocks. Theoretically, fissility may develop from orientation of the particles during deposition; but with abundant colloids and fine clay and the great water con- tent of the fresh deposits probably this rarely happens. It is, perhaps, more probable in the fresh-water deposits, with their smaller proportion of colloids, than in those of marine origin. Typical shaly structure is. perhaps. generally secondary and attributable chiefly to two gravitational processes: (1) Com- pression (condensation), which eliminates much water, reduces the thickness of strata (even to one-fourth of the origina! dimensions), flattens particles. and orients flaky and elongate fragments parallel to the bedding. (2) Plastic flow, which turns the longest axes into the direction of movyement—down the depositional slope. Each process is aided by the other and also by tidal oscillations and by vibrations due to waves, earthquakes, and offshore slumping. Flow is doubt- less largely dependent on colloids (alumina, silica, kaolin-like substances, ferric . hydrate, organic matter) and interstitial water, ceasing as particles attain rigid packing. Such fissility is metamorphic. In contrast with slaty cleavage, it is parallel to the bedding, since it results, not from tangential stress, but from gravita- tional adjustments due to loading. Much minutely flaky kaolin, chlorite, and mica in shale probably arises from this mild metamorphism. Perhaps natural gas and petroleum also form under these conditions. Expelled by condensa- tion, they migrate, in the presence of water, up the depositional slope and into coarser facies or the porous and cavernous parts of the old land on which the strata overlap. Vibrations and tidal kneading are also doubtless effective factors in the migration. The hydraulic principle probably operates only in the open spaces of the reservoir rocks. 64 PROCEEDINGS OF THE ANN ARBOR MEETING Experiments have shown that compression and flow produce parallel struc- tures in both soft and hard materials, and the processes enumerated must vield similar results in many homogeneous, fine-grained deposits. The efficacy and mode of operation of some of the factors concerned are, however, but im- perfectly known. Critical field observations and rigorous quantitative tests are urgently needed. Read by title. DEVELOPMENT OF SHRINKAGE CRACKS IN SEDIMENTS WITHOUT EXPOSURE 10 THE ATMOSPHERE BY W. H. TWENHOFEL (Abstract) axperimental work in the laboratory with two types of sedimentary ma- terials has shown that shrinkage or mud-cracks develop in these sediments without their being exposed to the atmosphere. Bentonite and powdered hematite, the latter from Mayville, Wisconsin, were used, the latter in only one experiment. The work with bentonite has been repeated many times and has been sustained by field observations, so that the results appear certain. Presented extemporaneously. OBSERVATIONS ON THE RANGE AND DISTRIBUTION OF CERTAIN TYPES OF CANADIAN PLEISTOCENE CONCRETIONS BY EDWARD M. KINDLE (Abstract) The concretions described are from the Quaternary sands and clays of Lab- rador, the Northwest Territories, and Ontario. The points discussed include the influence of the nucleus on the shape of concretions and deductions from localized distribution concerning some of the factors in their formation. Five types of concretions, which are primarily the product of lithologie con- trol, are described from the Ottawa Valley. The stratigraphic range of these Several types is indicated. Nomenclature suitable for discriminating some of these types is suggested. Presented in full extemporaneously. DISCUSSION Prof. T. T. QUIRKE: Certain surficial features on marlekor look like welts or small raised ridges; they may have been caused by the filling of shrinkage cracks by hardened material, followed by continued shrinkage of the main mass. Other concretion-like masses appear to have been formed by the rolling of mud balls down clay slopes, with the result that they carry upon their surfaces a sort of wrapping of clay layers about the central parts. ABSTRACTS OF PAPERS 65 Author’s reply: Professor Quirke’s observations on marlekor have been made in an area somewhat remote from the one in which my own studies were made, and it is possible that some of the specimens referred to by him may have a different genetic history from that of the marlekor of the Ottawa dis- trict. I am not prepared to explain just how the fissures in the interior of the marlekor originated, but the clay pebbles which may be seen in abundance along the Ottawa River in late summer certainly show no such features; neither do any of the mud balls which have come under my notice along the Bay of Fundy estuaries possess any features which suggest in any way a comparable origin for the marlekor. The best evidence, perhaps, that the marlekor were produced by the same general agencies which are responsible for the claystones occurring at a lower level in the clays, is found in the fact that, like them, they are confined to that portion of the clays which lies within a few feet of the surface. BOOM BEACH (ISLE-AU-HAUT, MAINE):'A SEA-MILL BY JOHN M. CLARKE (Abstract) A short beach with rocky floor and bounded at each end by rock cliffs, ex- posed to the full force of the Atlantic, so confines wave action as to prevent lateral dispersion of abrasive effects, with the result that all boulders consti- tuting the beach are ultimately reduced to forms of perfect symmetry. Presented in full extemporaneously. DISCUSSION Mr. CHESTER K. WENTWORTH: I was interested in Doctor Clarke’s paper be- cause of its bearing on the problem of the production of flat beach cobbles by abrasion. The idea is extant in many text-books that these are produced by the shoving of cobbles to and fro by the waves. The proof or disproof of this view waits for quantitative studies, and I should like to receive suggestions as to suitable localities for such studies. In particular, I wish to ask Doctor Clarke if there are at Boom Beach any facts which indicate a flattening of cobbles and boulders as abrasion proceeds. Mr. Cart O. DuNnBAR: While working along the western coast of Newfound- land I was strongly impressed with the fact that the structure of the rock exercises a controlling effect on the shape of the beach pebbles derived from it. In places along this coast there are thin-bedded, sedimentary rocks asso- ciated with dikes and flows of basalt, and the contrast in the prevailing shape of the pebbles derived from each of these types of rocks is most striking. The most homogeneous, igneous rock breaks down into fragments of subequal dimensions, which under the attack of the waves become rounded into sub- spherical forms. On the other hand, the banded sedimentaries break up into fiattish slabs and chips that ultimately become very oblate spheroids or disks of the shape of a watch, and although they take on the most perfectly rounded symmetry never approach a spheroidal form. Remarks were also made by Mr. Arthur Keith. V—BULL. GEOL. Soc. AM., VoL. 34, 1922 66 PROCEEDINGS OF THE ANN ARBOR MEETING CRYSTALLINE ROCKS OF THE PLAINS BY CHARLES N. GOULD Presented in full extemporaneously. Brief remarks were made by Prof. R. 8. Knappen. PRECAMBRIAN FOLDING IN NORTH AMERICA BY WILLIAM J. MILLER Presented in full extemporaneously. Remarks were made by Messrs. Ruedemann (by letter) and Coleman and by Miss Fuller, with reply by the author. NOTES ON THE SALT DOMES OF NORTH AMERICA BY E. DE GOLYER (Abstract) A paper describing the occurrence and structure of the salt domes of the Gulf coastal region of the United States and the Tehuantepec region of Mex- ico, with a discussion of theories of salt dome origin and a comparison with various European salt dome regions. Read by title. SOME STRUCTURAL FEATURES OF NORTHERN IDAHO BY JOSEPH B. UMPLEBY (Abstract) The Osburn fault crosses northern Idaho and presents conclusive evidence of a horizontal component of movement measurable in miles. The plane dips about 65 degrees from the horizontal and, incident to movement along it, sym- pathetic fractures hundreds of feet long have been opened and reopened, as shown by the sequence of mineral deposition in the Coeur d’Alene district. The reverse faults of the area have much less gouge than the normal ones, indicat- ing that they were caused by vertical rather than horizontal stresses. These stresses may have arisen from an underlying molten intrusion—a possibility supported by a detailed study of the ore deposits, which, in part at least. formed before the magma bed completely solidified. As the mineralization is believed to have accompanied the granite intrusion on the one hand and the faulting on the other, it is suggested that the great horizontal displacement along the Osburn fault represents gliding on a molten subsurface zone. Read in full from manuscript. ABSTRACTS OF PAPERS 67 DATA ON THE GEOGRAPHIC NOMENCLATURE OF THE SOUTHERN CALIFORNIA AND TEXAS REGIONS BY ROBERT T. HILL (Abstract) ’ Revised classification of the physiographic features of the Texas region, with sketch map. A revision of previous earlier classifications made by the author, with ac- companying sketch. A nomenclature map of the physiographic features of southern California. This diagrammatic map is an endeavor to name and outline the physio- graphic features of southern California. These comprise a large number of units which have not hitherto been satisfactorily presented. Presented in full extemporaneously. SECTIONAL MEETING OF FRIDAY AFTERNOON FOR GROUP B The section for the presentation of papers on stratigraphic, paleonto- logic, areal, and cartographic papers met, at about 2.45, in Room F 214, with Vice-President Robert T. Hill in the chair and Charles P. Berkey as Secretary. TITLES AND ABSTRACTS OF PAPERS OF GROUP B AND DISCUSSIONS THEREON SUCCESSFUL METHOD OF TEACHING HISTORICAL GEOLOGY BY GEORGE H. CHADWICK (Abstract) The writer’s success in teaching historical geology by first working back- ward from the present seems to be based on a sound pedagogical principle, previously employed by him successfully in the teaching of biology. The link- age of this with other factors of method for increase of interest will be briefly described. Read by title. ORDOVICIAN OVERLAP IN THE PIEDMONT OF SOUTHERN PENNSYLVANIA AND MARYLAND BY GEORGE W. STOSE AND ANNA I. JONAS Read by title in absence of the author. 68 PROCEEDINGS OF THE ANN ARBOR MEETING CHEMUNG STRATIGRAPHY IN WESTERN NEW YORK 1 BY GEORGE H. CHADWICK (Abstract) The upper Devonian of western New York consists of several thousand feet of terrigenous strata in which the outstanding terms have been “Genesee,” “Portage,” “Chemung,” and “Catskill.” It is now many years, however. since John M. Clarke, H. S. Williams. D. D. Luther, and others began to point out that these familiar subdivisions are not strictly successive units, but local and overlapping (or dovetailing) facies. Field studies under Dr. Clarke’s direction have now shown that the prin- ciples enunciated by him are applicable to these strata across the entire State of New York and beyond, into Ohio. The fossiliferous “‘Chemung” strata prove to occupy progressively higher horizons in passing westward, as do the red “Catskill” beds that overlie them throughout most of this stretch. Like- wise the comparatively barren ‘“‘Portage”’ strata rise steadily in the scale in a westerly direction, while black shales of ““Genesee” type pursue them upward. The careful tracing of key horizons across the State into Pennsylvania, to- gether with the writer’s previous study of the literature for the Ohio equiy- alents, leads to the correlations in the table herewith presented, in which ver- tical dark bands indicate the portions of each section usually ascribed to the “Chemung.” The units beneath Lake Erie are checked on well borings.* The defense of the upper portion for Ohio and Pennsylvania will be published separately. Presented in abstract extemporaneously. Brief remarks were made by Mr. David White and Dr. I. C. White, with reply by the author. CORRELATION OF THE POTTSVILLE AND LOWER ALLEGHENY FORMATIONS IN WESTERN PENNSYLVANIA BY B. COLEMAN RENICK 1 (Abstract) The reports of the Second Pennsylvania Geological Survey covering the region along the Beaver River and its tributaries, in Lawrence, Mercer, and Butler counties, show that the average interval between the Vanport limestone of the Allegheny formation and the Homewood sandstone, the youngest mem- ber of the Pottsville formation, is 50 feet. In the Foxburg quadrangle along the Allegheny River the average interval is 120 feet from the Vanport lime- stone to what is called the Homewood sandstone in that folio. The geologic section from the base of the Pottsville to the Vanport limestone was studied along the Beaver River between Homewood and Mercer. The Same members were then traced along the outcrop up one of the tributaries to 1 By permission of the Director of the New York State Museum. 2 Title in this Bulletin, vol. 33, p. 152. 1 Introduced by G. F. Kay. 69 CHEMUNG STRATIGRAPHY IN WESTERN NEW YORK CUYAHOGA | ASHTABULA | ERIE CO,, \CHAUTAUQUA|CATTARAUGUS| ALLEGANY | STEUBEN | CHEMUNG VALLEY | COUNTY COUNTY COUNTY COUNTY | COUNTY | COUNTY [Berea ss|Berea |Corry ss|Corry IIIT [Bedford sh Bedford Lc TT TTT Ce -—-——S— == = = = Se ee OO eee ee eee eee a a SS ee | Cussewago ss| Knapp beds | Knapp col. 4|i\IIIIHIIIIIIIII| [Riceville sh. 7Oswayo shs| Oswayo _|Illlilll? Hill Carfaraugusé| Cotfarauous ted beds 7 ous Catskill" choco/lare beds UNITS WAVE RLYAN D/O a ss Q Conewango form. aranrorod ; ; Welt Cr cg/8 Chadakoin Lower Chagrin } ower Waune |Chodokoin Chocolate beds | Chocolate uerey IMMUN Cyn Lo? |" ee | Girard sh}~ Volusia sh| Zone No//| _/ron ore. AUT Cuba ss. s2|Cuba ss [Northeast |WIN x | “Portage’or Northeast sit — Machias |, a ; |Shumla |i) | Shumla ss.| Unnamed ‘Rushford ; Westfield \iiiniiSi p> [| Waatretaas) 77°04 “Carton Ce 7 ea MD ears ee |Gowanda_| , | x |x | Gowanda sh| Gowanda bed\Gowanda _\Gowanda “Catskill” red beds Wells burg Sandstone y Nellsburg Y vsandstore CHAUTAVQUAN QO} £ iy 18 Q [Dunkirn | ren |x| Dunkirk sh| Dunkirk | | Hanover _| | x | Hanover sh. | Pipe Creek _| CUT HAM Pjee Cre oA [Grimes sz | Grimes 38) jypec, bog (Ahinestreet | Rhinest-t +6 IMI [Middlesex |Middlesex [Middlesex hl ARIEL ‘Tthinestreet"= Attica sh, Se | OUEST TOTTI TTS TTT SENECAN (Cashogua \(OlenteravAlULUL 70 | PROCEEDINGS OF THE ANN ARBOR MEETING the Beaver River as far as the Beaver-Allegheny divide; then down a tribu- tary which enters the Allegheny River near the northwestern corner of the Foxburg quadrangle. The same section was then studied along the Allegheny River from the northwest corner of the Foxburg quadrangle southward to the mouth of Redbank Creek, in the Kittaninny quadrangle. As a result of this study the writer believes that the upper Connoquenessing and Homewood sandstones of the Beaver River-Pottsville section are equiv- alent to the Homewood and Clarion sandstones respectively of the Allegheny River section. It appears that the Pottsville formation of the Foxburg folio should be extended to include the Clarion sandstone which is included in the Allegheny formation, and that the top of the Clarion sandstone should be regarded as the upper limit of the Pottsville formation in that region, because it is the equivalent of the Homewood sandstone of the Beaver River section, which is the first conglomerate-bearing member below the Allegheny forma- tion. On the basis of this classification, the Scrubgrass, Clarion. and Brook- ville coals of the Allegheny formation in the Beaver River valley are equiv- alent to the Upper Clarion, Lower Clarion, and Craigsville coals respectively of the Foxburg-Clarion folio. A brief study of the same members between Mayport, near the southeastern corner of the Clarion quadrangle, and Brookville, in Jefferson County, sug- gested that the Craigsville coal of the Foxburg-Clarion folio is the equivalent of the Brookville coal near Brookville. Detailed mapping of these members between Mayport and Brookville will be necessary, however, before their rela- tions can be established with certainty in that district. Presented in abstract extemporaneously. DIscUSSION Dr. GrorcE H. ASHLEY: The problem has a broad bearing because affecting the type locality. It is thought that the difficulty has arisen partly through misinterpretation of the rocks in the Kittaninny region by members of the United States Geological Survey. Further remarks were made by Mr. David White and Dr. I. C. White, with reply by the author. STRUCTURAL STUDY OF A PART OF NORTHEAST TEXAS WITH SOME STRATIGRAPHIC SECTIONS BY F. JULIUS FOHS AND HEATH M. ROBINSON 2 (Abstract) Part I. STRATIGRAPHY AND STRUCTURE, BY F. JuLius Fous Much new data on the geologic complex of northeast Texas is available from drilling of several hundred wells (two hundred wildecats) and our own study of the surface geology during the past five years. Fragmentary contri- butions of much value have been made by others, but, based on more complete data, we discuss general relationships and results. 1 Introduced by Charles Schuchert. ABSTRACTS OF PAPERS rp. Due to faulting, reliable stratigraphic sections have heretofore been difficult to obtain, but microscopic studies of well samples and studies of the large group of well logs yield much new information on the thickness of the several formations, the areal extent of the Woodbine sand, the development of Taylor chalk beds, and more precise location of contacts of Nacatoch, Midway, and Wilcox. - Pointing out, first, the larger structural relationships, we describe the Mexia Fault Zone, 5 miles wide and 150 miles long, lying 20 to 30 miles east of and parallel to the Balcones Fault Zone. These zones prove similar in char- acter, with three or more normal, parallel faults, arranged en echelon with ‘similar groups of faults lengthwise of the zone, accompanied by folding, always faulted. Cross-faulting is absent. Both zones follow rigid rock outcrops off- setting shale formations on their west. The Mexia zone effects a partial cut- ting off of ground waters and appearance of connate waters in connection with oil east of its easternmost faults, resulting in development of four oil pools. A stratigraphic table, together with cross and longitudinal sections, delineate stratigraphic variations; a sketch map shows relationship of major structural features, and a detailed contour map of a segment of the fault zone shows its local character. Part II. ORIGIN OF STRUCTURE, BY HEATH M. ROBINSON An analysis of the stresses producing faults as applicable to the structure under consideration is first discussed; next, the character of the stresses pro- ducing faults within described area is treated, showing that dominant stresses are vertical. The zone of offset faults suggests a general weak zone. We then discuss relationship between primary and secondary structural features in the tilting of the Gulf Coast area toward the sea, pointing out the genetic rela- tionship between them. The competency of Upper, Lower, and Pre-Cretaceous beds to transmit stresses is discussed. The general conclusion is reached that movement along deep-lying faults operating on underlying competent beds | would produce structural features on the surface beds similar to those found within described area. Read in full from manuscript. Brief remarks were made by Dr. Sidney Powers and others. THE LANCE PROBLEM BY FREEMAN WARD? (Abstract) Evidence from formations in South Dakota. Brief statement of facts on which there is agreement: also of points under controversy. Discussion of contact of Fox Hills and Lance. Attempt to harmonize conflicting paleonto- logic evidence. Break between Mesozoic and Cenozoic placed at top of Fort Union. Read by title. 1 Introduced by H. E. Gregory. TZ PROCEEDINGS OF THE ANN ARBOR MEETING OBSERVATIONS ON COAL SWAMPS IN NORTHERN WEST VIRGINIA WHERE PERMIAN CONDITIONS PREVAIL ; BY JOHN L. TILTON (Abstract) Observations in northern West Virginia the past two seasons emphasize the idea of extensive swamps, of mushy constituency beneath the surface, surface covering reedlike, the growing surface creeping out into bodies of water gen- erally fresh, where fresh-water limestone is in process of deposition. Low, fernlike plants (Cycadofilicales) are crowding out from the shore and distant > trees (tree-ferns?) are rising from the low upland. There is no large growth out upon the swamp at a distance from the shore. The large growths (tree- ferns?) are here confined to the margins of the swamps and to higher ground. The unusual view of a carboniferous swamp is thus the one that fits here where Permian conditions prevail, not the view of a carboniferous swamp that is commonly pictured. Presented in abstract extemporaneously. FURTHER CONTRIBUTIONS TO THE KNOWLEDGE OF THE CRETACEOUS OF THXAS AND NORTHERN MEXICO BY ROBERT T. HILL (Abstract) A. IMPORTANT AND NEWLY DISCOVERED CONTACT DISCONFORMITIES AT THE BASE . AND Top OF THE GULF SERIES, OR UPPER CRETACEOUS, IN NortH TEXAS During the past year I have had the pleasure of discovering in north Texas two important and hitherto undiscovered contacts, one each at the base and top of the Gulf series, or Upper Cretaceous (American usage), of the Texas region which had long been suspected to exist, but which, owing to the uncon- solidated and concealed character of exposures, have not hitherto been dis- covered. One of these contacts records a disconformity between the top of the Co- muanche series and the base of the Gulf series, and the other, 85 miles directly east, records a similar disconformity between the top of the Gulf series and the base of the Midway formation of the Eocene Tertiary. The first locality is situated on the north outer bluff of Denton Creek valley, in southern Denton County, about five miles east of Roanoke. It distinctly shows a disconformity between a Buda-like formation of limestone, with char- acteristic fossils, which here reoccurs in the top of the Grayson marls of the Comanche series and the base of the Woodbine. The molluscan fauna or spe- cies of the former is not known to cross into the latter. This contact is usually obscured by slump in north Texas and has hitherto been considered not proven. Its discovery settles the question of the identity of upper terminal beds of the Comanche series of north Texas with the Buda limestone of the Austin section, and demonstrates that the Woodbine formation lies completely above the latter and is not contemporaneous with it, as has been widely pub- lished by Bose and others. ABSTRACTS OF PAPERS ip The second locality, about two miles northwest of Lone Oak, Hunt County. shows the limestone of the Midway, with characteristic fossils, resting upon the clays of the Navarro beds of the Upper Cretaceous, with characteristic fossils. This is the second actually observed contact between these formations to have been recognized. The other is on the Rio Frio, some four hundred miles away. Accurate logs of oil prospecting wells show the thickness of the Gulf series between these localities and along this latitude to be 3,100 feet. Stratigraphic. paleontologic, and photographic details are given. B. STRATIGRAPHIC POSITION OF THE BUDA LIMESTONE OF THE SoutH TEXAS SECTIONS AND ITS RELATIONSHIP TO THE NoRTH TEXAS SECTION This paper gives additional proof of the stratigraphic correspondence be- tween the Buda limestones of the Colorado River section of Texas and the Grayson and Main Street formations of north Texas. It likewise asserts that the Buda formation is not synchronous with the Woodbine formation of north Texas, as erroneously asserted by Bose and collaborators, but that the latter lies above the former with a stratigraphic and paleontologic disconformity between them. It likewise clears up a previously. existing confusion, whereby the Tamasopa formation of Mexico has hitherto been erroneously correlated with the Woodbine instead of the Comanchean, to which it belongs. C. CHANGES OF LITHOLOGIC PHASE IN THE COMANCHE SERIES ADJACENT TO THE Rio GRANDE AND NOTES ON THE RECURRENCE OF DEEPER WATER LIMESTONE FAUNAS Shows the persistence of key faunas of the several divisions of the Co- manchean Cretaceous in sections between Red River and the Rio Grande of Texas, accompanied by frequent interpolations of Rudistean limestones along the latter. Presented in abstract extemporaneously. PALEOZOIC ROCKS FOUND IN DEEP WELLS IN WISCONSIN AND NORTHERN ILLINOIS BY F. T. THWAITES? (Abstract) The paper discusses the formations found in deep wells from the lithologic standpoint only. References to published material on the paleontology are given. The formation names given to the subdivisions of the Cambrian by Ulrich are here defined. Brief notes are given on the surface exposures of the formations. All formations from the Devonian down to the Precambrian are discussed, with special emphasis on the water-bearing Cambrian. The methods by which the deeply covered formations were correlated with those exposed in central Wisconsin are explained in detail. Several cross-sections illustrate the paper. Read by title. 1—ntroduced by W. O. Hotchkiss. 74 PROCEEDINGS OF THE ANN ARBOR MEETING MERGING OF THE CARLILE SHALE AND TIMPAS LIMESTONE FORMATIONS IN SOUTHEASTERN COLORADO BY EHS Bo EAs Oy) Read by title. PRESENT STATUS OF THE GEODETIC WORK IN THE UNITED STATES AND ITS VALUE TO GEOLOGY ‘ BY WILLIAM BOWIE (Abstract) The geodetic work of the United States, now carried on by the United States Coast and Geodetic Survey, is supplemented to a small extent by the Topo- graphic Branch of the United States Geological Survey and by several cities. There are now in the United States, in addition to the coast triangulation, 20,000 miles of arcs of precise triangulation and traverse, furnishing the geo- graphic positions of many thousands of points or stations. Precise leveling was begun in the United States by the War Department in connection with river improvements and control. Later, this work was begun by the Coast and Geodetic Survey to furnish accurate elevations for the reduction to sealevel of measured base lines. There are now 47,000 miles of precise leveling in the United States, furnishing the elevations of 18,500 bench-marks. The triangu- lation and precise leveling are essential in the preparation of accurate topo- graphic maps, without which geologists carry on their field-work with great difficulty. A modification of the von Sterneck type of pendulum was made in the United States Coast and Geodetic Survey, under the direction of Dr. T. C. Mendenhall, then Superintendent, which has been used to determine the in- tensity of gravity at 3800 stations in the United States. The geologists are interested in the gravity work because the data furnished by the observations have been extensively used to supplement the isostatic investigations based on triangulation and astronomic data. The geodetic data furnish accurate physical measurements of direction, dis- tance, and force, which are more effective than any other means in throwing light on the constitution of that part of the crust of the earth which is beyond the possibility of direct observations and measurements. Presented in abstract extemporaneously. Brief remarks were made by Mr. David White. RECONNAISSANCE TRAVERSE FROM MOJAVE ULOJANE, CALIFORNIA, TO ROCK CREEK, UTAH BY HERBERT E. GREGORY (Abstract) The work described includes location of fault south of Death Valley; tracing Mesozoic from Spring Valley Mountains to mantle of San Juan; restudy of the Kanab section of Walcott; definitions of the “Marine Jurassic” and Kaibab; and extension of the Supai-Hermit unconformity. Presented in abstract extemporaneously. ABSTRACTS OF PAPERS 75 TOPOGRAPHY AND GEOLOGY OF THE OKANOGAN HIGHLANDS AND COLUMBIA PLATEAU OF WASHINGTON BY SOLON SHEDD (Abstract) A general discussion of the surface features and geology of the eastern part of Washington. The Okanogan Highlands constitute a large area of meta- morphic rocks, part of which was probably originally sedimentary and part igneous. The Columbia Plateau, as used in this paper, refers to that part of the great lava field, in the northwestern part of the United States, which lies within the State of Washington. The surface features of parts of this area are very interesting and are a result, partly at least, of the action of the wind. Read by title. TERTIARY STRATIGRAPHY IN THE LOWER RIO GRANDE REGION BY ARTHUR C. TROWBRIDGE (Abstract): A reconnaissance map is presented covering about 13,500 square miles in extreme south Texas. Formations are described. A change in the strike from a northeast-southwest direction in Medina County to a north-south direction in Webb County, and to a north by northwest-south by southeast direction in Zapata and Starr counties, explains some previous differences of opinion con- cerning the ages of beds and faunas along the Rio Grande between Laredo and Rio Grande City. Partly on stratigraphic evidence and partly on the basis of fossil plants identified by Berry, the Carrizo sandstone of Owen is placed in the Wilcox rather than in the Claiborne, and a new formation, the Bigford, is recognized between the Carrizo and the Mount Selman, the lowest Claibornian formation. Read by title. The section adjourned at 4.37 p. m. ANNUAL DINNER At 7 o'clock p. m. the Society and its visitors and guests, together with members of the Paleontological Society, the Mineralogical Society of America, the Society of Economic Geologists, and the Association of American Geographers, assembled in the Michigan Union for the annual dinner. There was a very large attendance, and the attractive appoint- ments of the place, with its splendid service, made this one of the most successful and enjoyable events of the kind ever experienced by the Society. President Schuchert presided and in due time, with appropriate re- marks, introduced Prof. H. E. Gregory, who served as toastmaster. In- 76 PROCEEDINGS OF THE ANN ARBOR MEETING formality and simplicity of program, coupled with uniform good humor of both speakers and listeners, combined to make the occasion both highly enjoyable and a real recreation in the midst of three days of strenuous scientific meetings. Responses to the call of the toastmaster were made by Prof. Emmanuel de Margerie, Correspondent of the Society; J. E. Spurr, for the Society of Economic Geologists; E. T. Wherry, for the Mineralogical Society of America; T. Wayland Vaughan, for the Paleontological Society; Walter C. Mendenhall, for the United States Geological Survey; Wilbur A. Nel- son, for the Association of State Surveys, and by R. A. Daly, A. C. Law- son, James F. Kemp, W. H. Hobbs, E. O. Hovey, William North Rice, and John M. Clarke. GREETINGS TO FOREIGN SOCIETIES By unanimous vote the Secretary was instructed to cable the cordial greetings of the Society to the Geological Society of France, Professor de Margerie being our honored guest, and to write cordial letters of greet- ing -and good wishes to the Geological Society of South Africa, the Geo- logical Society of China, which was organized only last autumn, and to Sir T. Edgeworth David, of Australia. After the close of the dinner these instructions were carried out. RESOLUTION OF APPRECIATION OF E. 0. HOVEY, RETIRING. SECRETARY This occasion was used also as an opportunity to express appreciation of the faithful and efficient service of Dr. E. O. Hovey, Secretary of the Geological Society of America for sixteen years. Prof. James F. Kemp made the address in presenting a beautiful silver loving cup to Dr. Hovey as a token of the respect and good-will of the members of the Society. The following resolutions were then read and enthusiastically adopted: “At the present annual meeting Dr. Edmund Otis Hovey, Secretary of the Society since December, 1906, is, at his own wish, retiring from office. The undersigned committee has been appointed by President Schuchert to prepare an appropriate resolution and present it for action by the Society. “Dr. Hovey has held for sixteen years the responsible and exacting office of Secretary. During all this time he has shown exceptional devotion and unsparing fidelity in the discharge of the duties of his office. Under his tenure the Society has maintained the high ideals with which it started on its career thirty-four years ago, and has done so in no small degree because of the influ-_ ence and sound judgment of its Secretary. The publications have also held true to the exalted standards now long established. “Dr. Hovey has witnessed during his official life, and has shared in carrying through, at least one important change in policy and organization—that relat- RESOLUTIONS OF APPRECIATION OF E. 0. HOVEY DL ing to the affiliated societies. The Paleontological Society became the first affiliate, the Mineralogical Society of America the second, and last year the Society of Economic Geologists joined the group. By this wise arrangement excessive and weakening subdivision is avoided, while a large degree of prac- ticable unity is maintained. ~ “The Geological Society desires to express and record upon its minutes a warm and cordial expression of appreciation of the unselfish service given by its retiring Secretary and to wish him the successful completion of the scien- tific labors to which he desires to give his entire efforts and attention. (Signed ) JAMES F. Kemp, Chairman. JOHN M. CLARKE. RAE Penrose; JR.’ To this Dr. Hovey, in retiring from this long and useful service, re- sponded briefly and with more than a touch of feeling, as he recalled many years of intimate association with the leading men in American geology. REPLY BY EDMUND OTIS HOVEY Mr. Toastmaster, Professor Kemp, Fellows of the Geological Society of America and other friends, you have quite overwhelmed me with your feeling introduction, with the splendid resolutions, which give me more eredit than I deserve and which will always be preserved with my most treasured archives, and with this beautiful token of your affectionate regard, which will ever remind me of my long term of most enjoyable — service as Secretary of the best scientific society in the world. You may rest assured that I shall follow Professor Kemp’s injunction to make the vase “say it with flowers” as a memento to my family of the hosts of friends that my relations with the Society have brought me. I am so greatly affected by all this that I cannot express my feelings in words, or reply adequately to the graceful pre-obituary that Professor Kemp has pronounced regarding me. I can only say I thank you all from the bottom of my heart. During my incumbency as Secretary about one hundred different men have served on the Council, and they have been drawn from all parts of the country—the representative geologists of America. The close asso- ciation with such men as Van Hise, Calvin, Gilbert, Hague, Davis, Fair- child, E. A. Smith, Becker, Coleman, Clarke, Adams, Cross, I. C. White, Merriam, Kemp, and Schuchert—to name only the presidents in suc- cession—has been of inestimable value to me. My relations with the efficient treasurers of the Society, the lamented W. B. Clark and his successor, E. B. Mathews, and with the hard-worked editor, Joseph Stanley-Brown, have been even more intimate and have 78 PROCEEDINGS OF THE ANN ARBOR MEETING led to the warmest of friendships. I cannot let this occasion pass without recording my testimony to the serious deyotion to the Society shown by the successive councils and the faithfulness with which they have done their labor of love. From time to time indeed some of the Fellows have voiced some criticism of the conservatism of the governing body; but when these objectors have been taken on to the Council, as they have been when practicable, they have observed the wisdom which has prevailed there, have noted the consideration which always has been given to eriti- cisms, and have uniformly agreed with their colleagues in the conduct of the business of the Society and in the maintenance of the high standards of admission to Fellowship. A brief survey of the principal events and impressions of the past six- teen years and a few statistics may be of interest to you at this time. Of the 112 men who were enrolled as Original Fellows on the first list issued by the Society, 26 had died and 26 had resigned or dropped out by 1906, leaving 60 on the roll then. At the close of 1922 there were only 27 Original Fellows left, 30 having died and three having resigned in the sixteen years. From 1889 to 1905 the Society elected 287 persons to its Fellowship, and from 1906 to 1921, inclusive, added 286 to this number, a total of 573. There are now 439 elected Fellows on the roll, 134 having dropped out through death, resignation, and failure to maintain their dues. One man is counted twice in this summary, he having resigned as an Original Fellow, and later, on his repentance, having been reelected as a Fellow. There have been, up to the present annual meeting, 678 men and six women connected with the Society as Fellows. In 1909 the Society inaugurated a new class of members by electing seven eminent foreign geologists correspondents. In 1910 six men and in 1912 three more were added to this list. In 1914 six nominations to correspondent- ship were made by the Council, but on account of the beginning of the Great War the names were not presented at the election of that year. In 1921 one correspondent was elected. Six correspondents have died, hence there are now 11 names on the list in this class. The total mem- bership of the Society at the close of 1922 is therefore 474. The formation of daughter or affiliated societies began in 1909 with the organization of the Paleontological Society, a vigorous offspring which has gained strength with the passing years, but which still loyally remains under. the wing of the parent society. In 1920 a@ second child was born, the Mineralogical Society of America, which has been some- what more independent in its existence, since it has maintained a sepa- rate channel of: publication. Close relations with the Geological Society REMARKS OF E. O. HOVEY, RETIRING SECRETARY 79 of America are secured by these societies through exchange of voting rep- resentatives on the respective Councils. In 1920 a third society, the Society of Economic Geologists, came into being as one of our affiliates, the affiliation being recognized by an exchange of non-voting delegates between the two Councils. The formation of these branch societies is an important step in the history of geological science in our country, and it should be guided so as not to injure the parent society. The publication of the Bulletin has kept on its sturdy way under the hand of the same able editor, Joseph Stanley-Brown, who gave it such prestige as to form an excellent appearance under Secretary Fairchild. May he continue long in the editorship! The papers submitted for pub- lication have come first to the Secretary, and all the scientific contribu- tions except the presidential addresses have been sent out to censors selected by or through the Council for consideration as to acceptability for publication by the Society. This handling of the subject-matter of the Bulletin forms no small part of the Secretary’s duties, and I wish here to commend the thoroughness and justness with which the numerous censors have performed their anonymous tasks through love for the Society. The censoring of the papers has contributed largely to the high standard of our Bulletin. The sales of the Bulletin have been an important source of income to the Society. Up to the close of 1906 the sum of $9,602.34 had been de- rived from this source, and in the sixteen years which followed (to No- vember, 1922) the sales amounted to $22,955.21, an average of $1,434.70 per year. In the year 1906 the receipts from sales were $736.25, whereas in the year ending November 30, 1922, they were $2,004.60. In the ' three weeks of December which have elapsed since the fiscal year closed, two complete sets of the Bulletin have been disposed of, and the total sales have been increased some $600. In 1908 all the American exchanges were eliminated from our list of distribution and the price of the Bulletin to libraries was placed at $7.50 per volume. In 1920 a further increase to $9 per volume was made necessary by the high cost of printing and paper. We now have some 158 regular subscribers to our Bulletin and 98 foreign exchanges. These statements give some intimation of the growth of the purely clerical work connected with the Secretary’s office during the past decade and a half. We have been sailing very close to the financial wind during the past few years by reason of the rise in the costs of publication and clerical assistance, but by the strictest economy on the part of the officers of the Society we have thus far avoided any increase in our annual dues. These 80 PROCEEDINGS OF THE ANN ARBOR MEETING still remain the same as they were at the organization of the Society, when a dollar could buy more than twice as much as it does now. During the long period now closing I have not missed a meeting of the Society or of the Council, except during the two years of my enforced absence in the Arctic, when my able successor, Prof. C. P. Berkey, stepped into the breach. I was deeply touched by the generous contribution which the Society made to the Crocker Land Expedition to assist in bringing me home. The close and harmonious association with my col- leagues during all these years has been most pleasing. This, with the service rendered to our science, is what makes the Secretaryship of the Geological Society of America worth while. It is a real recompense for the hours and hours of labor necessarily devoted to the discharge of the many and sometimes onerous duties connected with the position. SESSION OF SATURDAY MorRNING, DECEMBER 30 The morning session was called to order by President Schuchert, in the auditorium of the Natural Science Building, at 9.50 o'clock. TITLES AND ABSTRACTS OF PAPERS AND DISCUSSIONS THEREON, PRESENTED BEFORE THE MORNING SESSION GEOLOGICAL RECONNAISSANCE IN MONGOLIA BY CHARLES P. BERKEY (Abstract) The data covered by this paper were gathered during the past field season, while acting as geologist for the Third Asiatic Expedition of the American Museum of Natural History, New York. Five months were spent in the deserts and mountain ranges of central Asia. An itinerary of over three thousand miles gave opportunity for widely ex- tended observations. As much attention as possible was given to geologic structure, stratigraphic succession, formational subdivisions, paleontologic content, deformation history, and physiographic development. More definite statements can be made on these questions than were previously available. The account is intended to cover an advance summary of the investigation and its results. Presented in abstract extemporaneously. I)ISCUSSION Mr. D. F. Hiacins: Remarkable is the fact of the great thickness of post- Paleozoic sediments in Mongolia. Near Nan-K’ou Pass, northwest of Peking, I have measured about 20,000 feet of later Proterozoic sediments of von Richt- ABSTRACTS OF PAPERS 81 hofen’s ‘“‘Nan-K’ou Series.” One can well wonder at the tremendous sedi- mentary records on the Asiatic Continent. PROBLEM OF MILD GEOLOGICAL CLIMATES BY ELLSWORTH HUNTINGTON (Abstract) A mild climate, with relatively slight contrasts from latitude to latitude and season to season, appears to have prevailed throughout most of geological times. The solar cyclonic hypothesis, when combined with the distribution of land and sea, appears to offer an adequate explanation. Recent investigations show that the cyclonic circulation which gives rise to the typical storms of temperature latitudes and the hurricanes of lower latitudes is intimately de- pendent upon variations in solar activity. Moreover, an analysis of the rela- tionships of different parts of the sun’s disk to barometric conditions over the north Atlantic Ocean and to atmospheric electricity shows a relationship which ean not apparently be thermal and which seems to be in harmony with an electrical cause. If this is the case, the sun might be as hot as now, and yet cyclonic storms of all kinds might be greatly reduced if the sun’s atmosphere were relatively undisturbed. In that case, the earth’s mean temperature would rise, as it does now at times of few sunspots when storms diminish in number. The chief reason for this would apparently be that far less warm air would be drawn from low latitudes and pushed aloft in the centers of storm areas. At the same time the strength of the normal planetary and continental circu- lations would be increased, because they would suffer less interference from storms. If this happened and if the conformation of the land were such that warm currents easily penetrated to high latitudes, there seems to be no good reason why polar regions should not have enjoyed a climate as warm, perhaps, as that of Ireland. Presented in full extemporaneously. Brief remarks were made by Messrs. Leverett and Coleman. FURTHER EXPERIMENTS ON THE FRACTURING OF HOLLOW BRITTLE SPHERES AND THEIR BEARING ON MAJOR DIASTROPHISM BY WALTER H. BUCHER (Abstract) In a paper read at the Chicago meeting of the Geological Society, the writer presented the results of experiments which showed that the pattern of frac- tures which form when hollow spheres of glass and of paraffin are fractured by the expansion of water freezing in them, is essentially similar to that shown by the Mesozoic geosynclines as reconstructed by Haug. He further showed that it is possible to explain the origin of the major geosynclines on the basis of such subcrustal expansion. The purpose of this paper is to present the results of experiments made in the Physics Department of the University of Cincinnati by Dr. R. C. Gowdy VI—BULL. GEOL. Soc. AM., VoL. 34, 1922 82 PROCEEDINGS OF THE ANN ARBOR MEETING and the writer, in which such spheres were subjected to hydrostatic pressure. In the first series of experiments, thin-walled, hollow glass spheres were thus fractured under compression. In the second series, spheres were used which more nearly correspond to the conditions involved in the deformation of the earth’s crust. Finally, an attempt is made to use these experiments as the foundation for a consistent theory of major diastrophism. Read from notes. DISCUSSION Prof. W. H. Hopss: Any one who has read Professor Bucher’s classical study of ripple-marks will attach importance to any other investigations which he makes. I was one of those who offered objection to the claimed applica- bility of his experiments on frost-expanded glass balls to the problems of coastal deformation. I must offer objection now to the later series of experi- ments here presented, on the ground that they do not simulate in any close way the probable stress systems involved in coastal deformation. Brief remarks were also made by Mr. F. P. Shepard, with reply by the author. SOME STRUCTURAL FEATURES OF THE PLAINS AREA OF ALBERTA CAUSED BY PLEISTOCENE GLACIATION BY OLIVER B. HOPKINS Read in abstract from manuscript. Brief remarks were made by Messrs. Hobbs and Hill. CORRESPONDENCE BETWEEN THE GONDWANA SYSTEM OF HINDUSTAN AND THE NEWARK SYSTEM OF THE EASTERN UNITED STATES BY WILLIAM H. HOBBS (Abstract) The Gondwana system of Hindustan presents striking parallels with the Newark system of the eastern United States. These correspondences are espe- cially: (1) the coarse, often red, and sometimes markedly feldspathic ma- terials derived from the Precambrian; (2) the unity of the sedimentary series and its slightly tilted attitude; (5) the occurrence as isolated erosional rem- nants preserved by inset within crystalline rocks and bounded by faults; (4) the elaborate system of intersecting hear-vertical faults and the abundance of basic flows and dikes: (5) intercalated coal seams and ganoid fishes as char- acteristic fossils: (6) the nature of the differences which characterize the several areas of each system among themselves. The American Newark has been regarded as probably of Jura-Trias age, based upon the fossils found in the northern areas. The Gondwana system has been definitely shown to have areas of lower, middle, and upper Gondwana age, and these range from the Pennsylvanian to the Jurassic. In most physical aspects the lower Gondwana closely resembles the southern Newark areas, as ABSTRACTS OF PAPERS © 83 the middle and upper Gondwana do the more northern. The lower Gondwana has a basal conglomerate of glacial origin (Talchir beds). During the present season a rapid reconnaissance was made of the Wadesboro area of Newark rocks in North Carolina in the hope of discovering either Pennsylvanian fossils or a glacial conglomerate. Faceted pebbles, but without striw, were found at the base. Proceeding northward to examine the Deep River area, it was learned from Prof. Collier Cobb that he had already discovered, but not yet described, excellent Pennsylvanian fossils from that area, thus confirming the anticipated correspondence in age with the lower Gondwana of Hindustan. Geologists more favorably located should make further search for glaciated pebbles in the basal conglomerates of the southern Newark areas. Presented in full extemporaneously. DISCUSSION Prof. E. W. Berry: It is perhaps unfair for one who has seen only the ab- stract of this paper to pretend to criticise its conclusions, but the statements in the abstract are certainly open to criticism, and I would like to point out the harm which, in my judgment, the author does to geological science by such unestablished and far-fetched comparisons as that between the Newark rocks of eastern North America and those of the Gondwana system of India. I venture to assert that the two series have nothing in common except such features as result from their both having been deposited under continental conditions. That portion of the Newark which is fossiliferous, and this includes the Connecticut, New Jersey, Pennsylvania, Virginia, and North Carolina areas, is not “probably of Jura-Trias age,” but is most clearly and conclusively shown _ by its fishes, reptiles, mammals, and plants to be not older than the Keuper of Europe, nor younger than uppermost Triassic. These fossils are not con- fined to the northern area of the Newark, although the so-called Ganoid fishes have been described principally from that area. The mammalia, many rep- tiles, and the best of the plant materials have come from Virginia and North Carolina. Professor Hobbs is mistaken in his statement that the lower Gond- Wana most resembles the southern Newark area, and that the middle and upper Gondwana most resembles the northern Newark area. Paleontologically, and by that I mean both paleozoologically and paleobo- tanically, there is absolutely no age distinction between the northern and southern areas of Newark rocks. All of the extant evidence is in harmony in pointing to a late Triassic age, and this evidence is overwhelmingly strong for the Virginia and North Carolina areas. Professor Hobbs is mistaken in thinking that he has discovered Pennsylvanian fossils in the Triassic of the Deep River area of North Carolina. With very considerable faunas and floras known from the Newark rocks, and with the well considered opinions as to age based on comparatively recent studies of the Newark fishes by Eastman, of the vertebrates of the North Caro- lina Triassic by Gilmore, and the mostly unpublished studies of the Triassic plants of the southern area by the writer, it would seem that Professor Hobbs’ conclusions are not in accord with our present knowledge of the subject. nor do they, it seems to me, add anything to that knowledge. 84 PROCEEDINGS OF THE ANN ARBOR MEETING Mr. C. K. WENtTWorRTH: While I am indebted to Professor; Hobbs for his suggestion as an addition to my collection of hypotheses for the origin of the striated and faceted pebbles which are widespread in the basins of the James and Potomac rivers, I am forced by the facts to take a very skeptical attitude toward his suggestion. These pebbles and boulders were deposited in early Pleistocene time. The evidence is overwhelming that they were striated in early Pleistocene. Great blocks and boulders, as well as blocks of fragile rocks widespread over the coastal plain, point to ice flotation, indicating the activity of ice far beyond that of the present time. The westernmost occur- rence of the striated cobbles is at the edge of the Allegheny Plateau, 160 miles west of any known areas of Triassic rocks. Professor Hobbs has suggested the derivation of the striated pebbles of the Pleistocene from an area of Trias- sic rocks which have since been removed by erosion. The convergence of early Pleistocene grades with the present grades of the Potomac River at a point near the westernmost occurrence of the striated pebbles indicates that post-early Pleistocene erosion is here to be measured in scores rather than hundreds of feet. The total removal since early Pleistocene time of a Triassic remnant capable of yielding the large quantities of striated pebbles found on the coastal plain is unlikely. So far as my familiarity with the Triassic con- glomerates of the Potomac basin goes, I know of no pebbles or cobbles in these rocks which in any important way resemble the smoothed, faceted, and striated pebbles under discussion. The derivation suggested seems wholly untenable. Dr. SipNEY Powers: I wish to call attention to the fact that the Squantom tillite near Boston compares in age with the glacial beds in India. The Trias- sic formations in Nova Scotia show no evidence of glaciation. Mr. GEorGE C. Martin: I wish to protest against the general acceptance of faceted and striated pebbles as proof of ancient glaciation. Such evidence has been generally accepted for the supposed continental Gondwana glaciation as well as for glaciation during other periods in pre-Pleistocene time, and that the faceted pebbles from the Newark beds afford such evidence appears to be unquestioned by Professor Hobbs. The frequent present-day transportation of glacial pebbles by ordinary river ice and by floating snags and driftwood for long distances from their source in alpine glaciers or in eroded Pleistocene deposits and their coming to rest in the fluviatile, lacustrine. or marine de- posits that are now forming in non-glaciated regions is sufficient to show that stronger evidence than even abundant glacial pebbles should be required as proof of glaciation in the locality where the pebbles are found, or of a glacial period at the time when the pebbles were deposited in their present position. The presence of glacial pebbles in ancient conglomerates proves only, in my opinion, that mountains have existed throughout nearly all geologic time, and that the processes of precipitation, erosion, and transportation have always been effective. Moreover, striated and faceted pebbles can be produced without the agency of even local alpine glaciers. The banks of Yukon River from high water at least to low-water mark, in many places, have a natural pavement of cobbles. The grinding of ordinary river ice, with the embedded sand and gravel that it picks up on the banks as it passes down the river each spring, has produced facets, scratches, and polished areas on the upper surfaces of the cobbles of the pavement. That these marks are of non-glacial origin is shown by the fact ABSTRACTS OF PAPERS 85) that they occur only within the range of the floods, usually only on the upper surfaces of the cobbles, and on cobbles of undoubted local origin in a region that has never been glaciated. If I am not mistaken, I have even seen articles of modern human manufacture that bear such marks. Such cobbles after being faceted on one side are sometimes turned over and acquire other facets. They then bear a very marked resemblance to glacial pebbles and are indis- tinguishable from the faceted cobbles from the Potomac Valley which Pro- fessor Hobbs believes may be derived from glacial Newark conglomerates. I believe that such effects may be produced on the banks of any river that has occasional ice jams. The grinding of the large volume of ice that passed down the Potomac in March, 1918, in my opinion, may have been sufficient to pro- duce such marks, and such ice jams if repeated many times would certainly do so, for the cobbles embedded at the surface of the mud, especially if the mud were frozen, would remain in place and receive repeated scourings. Facets and striz can also be made without ice action of any kind. If a conglomerate that is not so strongly cemented that it will break across rather than around the pebbles is sheared, the pebbles will grind against each other and many of them will receive facets and stri# that are indistinguishable from those of glacial origin. Of course, the movements may be so localized that ordinary slickensides will result. But if the conglomerate is but weakly cemented, or if it is in a position approaching the zone of flowage, the move- ment may be distributed throughout its mass, so that many faceted pebbles may result, or even the whole conglomerate may be so thoroughly ground up that it resembles a tillite. I believe that many supposed ‘“‘tillites” have this origin. Some of the early Tertiary conglomerates in the Matanuska Valley, Alaska, contain abundant faceted and striated pebbles that apparently are as characteristically of glacial origin as the recent glacial pebbles of the same region, yet these conglomerates are interbedded with rocks that contain warm- climate plants, including even palms. I broke open one of these pebbles, which proved to have been slightly sheared, and found that the “glacial striz’’ inside ‘the pebble were just like those on the outside. Mr. Davin WuiIteE: In his parallel between the Atlantic Trias and the di- visions of the Indian Gondwana, Doctor Hobbs seems to have given great weight to the points of physical resemblance. The statement as to the paleon- tology of the Deep River basin appears to constitute corroboration from an outside source. I fear, however, that Doctor Hobbs has given too ready ac- ‘ eceptance to a Paleozoic reference of the Deep River beds, which should not be classed as Permian before the fossils are passed on by, the appropriate special- ist or specialists. QUANTITATIVE CRITERIA IN PALHOGEOGRAPHY BY RAYMOND C. MOORE (Abstract) Volumetric determinations of geological formations afford information, in certain instances, of paleogeographic significance; but, due to the quantita- tively unknown values of various components, definitely detailed conclusions are not ordinarily possible. Concerning assumed distribution of sea and land 86 PROCEEDINGS OF THE ANN ARBOR MEETING at various times, as in the case of supposed continental masses like Gondwana- land, Atlantis, and the intercontinental land-bridges of biogeographers, con- sideration quantitatively of total land and sea areas is important. Unless wholly unwarranted assumptions as to change in the volume of the seas are made, the depth of oceanic depressions must, in a measure, be related to total marine area. Some published paleogeographic maps indicate world seas so reduced that if the waters were actually restricted to areas designated, the containing depressions would have to be excessively deep. 4 Presented in abstract from notes. DISCUSSION Prof. C. ScHucHERT: I am pleased to see Professor Moore trying to get at the quantitative values of the marine transgressions. It is a most difficult problem, and all the more so when a good geologist makes of the entire Pacific basin a continent in order to explain more easily the existence of his circum- ferential geosynclines. That the present continents were larger in geologic time than they are now most geologists admit, but how far they extended be- yond the present shorelines is a vexed question. Since the ocean bottoms move as well as the continents, great areas of the latter have been fractured into the oceanic deeps, and active volcanoes and thermal springs are con- stantly increasing the volume of water, while great quantities of it are being taken up by the lithosphere. These factors make the problem of quantitative oceanic oscillations almost unsolvable. Nevertheless, the problem must be kept in mind, and, as well, that of the theoretic placement of continents where now are oceanic deeps. Further remarks were made by Mr. Higgins, with reply by the author. KEWEENAW GEOTHERMAL GRADIENTS AND THE ICH AGE BY ALFRED C. LANE (Abstract) The rate of increase of temperature in the deep copper mines averages about 1 degree Fahrenheit in 105 feet, but is greater in depth, about 1 degree Fahren- heit in 90 feet. While the mean air temperature in Calumet is 39.4 degrees, the mean ground temperature is over 45 degrees, owing to the blanketing effect of snow. The change in gradient is due to a rise in surface temperature from freezing (32 degrees) to 48 degrees about 11,000 years ago. The deeper gradient is only what might be expected with rocks of this dif- fusivity, low in pyrite, with no signs of recent exothermal reactions, low in radioactivity. Exhaustion of heat from below in early times and an exceptionally thick crust, as indicated by isostatic observations, are also to be taken into account. Presented in abstract from notes. Brief remarks were made by Messrs. Daly and Van Nostrand, with reply by the author. ABSTRACTS OF PAPERS 87 VOTES OF THANKS At the close of this, the last general session of the meeting, most hearty votes of thanks were passed to President Burton and the Board of Regents of the University of Michigan for the generous hospitality extended to the Society in connection with the thirty-fifth annual meeting, and to the local committee, particularly to its chairman, Prof. Walter F. Hunt, for the perfection of the arrangements which had made the Ann Arbor meet- ing of the Society memorable for comfort and convenience in all of the requirements of a large and complicated program. SATURDAY AFTERNOON SESSIONS Two sectional sessions were held simultaneously on Saturday after- noon. The papers of Group A, of dynamical, structural, glacial, and physio- graphic nature, were read in the auditorium of the Natural Science Building. President Schuchert opened this session, with E. O. Hovey acting as Secretary. . Papers of Group B, of petrologic, mineralogic, and economic nature, were read in Room G 217, with Vice-President H. S. Washington in the chair and F. E. Wright acting as Secretary. TITLES AND ABSTRACTS OF PAPERS OF GROUP A AND DISCUSSIONS THEREON PHYSICAL HISTORY OF THE COLORADO FRONT RANGE BY F. M. VAN TUYL AND G. W. MACH AMER (Abstract) The Front Range represents a great anticlinal uplift locally faulted and everywhere profoundly eroded. The Cretaceous and older sedimentaries which once covered the area have been entirely removed over the crest of the struc- ture, thus exposing the Precambrian crystallines. The appearance of a large amount of volcanic debris in the Denver and Middle Park beds indicates igneous outbreaks in the range at the time they were deposited. In the present foothills area a few lava flows and dikes were formed at this time. There is evidence that the basaltic flows of North and South Table Mountains at Golden were derived from a volcano on North Table Mountain itself, rather than from a fissure now occupied by a dike several miles to the north. : The appearance of boulder beds in the upper portion of the Denver forma- tion suggests readjustments in the mountains to the westward, possibly pre- liminary to the great uplift. Subsequent to the deposition of the above-men- tioned continental fans there were profound orogenic movements which de- 88 _ PROCEEDINGS OF THE ANN ARBOR MEETING formed these sediments as well as the older ones. The foothills monocline was developed at this time. The date of the post-Denver orogeny has not been definitely fixed. In the Wet Mountains area, directly south of the Colorado Front Range, R. C. Hills found evidence of pronounced movements succeeding the Eocene Bridger. It is possible that there were two or more Eocene uplifts. Some students of Rocky Mountain geology believe that a peneplain was devel- oped in the Front Range in mid-Tertiary time. In the Cripple Creek district, Lindgren and Ransome report evidence of a prevolecanic plateau upon which the fragmental debris of the Cripple Creek volcano was spread. If a mid- Tertiary peneplain existed, a renewed uplift of the range must have taken place in late Miocene or early Pliocene time. Near the close of the Tertiary this erosion surface was bowed upward. The late Tertiary uplift inaugurated the present cycle of stream erosion. There is evidence that preglacial erosion proceeded much more rapidly in the foothills area than within the higher por- tion of the range. The present relief features of the foothills undoubtedly resulted very largely from preglacial erosion, since the glacial gravels, as shown by their present relationship, partly buried a topography very similar to the present one. Read by title in absence of authors. STRUCTURAL FEATURES OF THE COLORADO PLATEAU AND THEIR ORIGIN BY RAYMOND C. MOORE (Abstract) The Colorado Plateau is an elevated region, comprising portions of Utah, Colorado, Arizona, and New Mexico, which is mainly composed of essentially flat-lying sedimentary formations ranging in age from Cambrian to Tertiary. Aside from gentle warping, which has affected all of the region, the stratified rocks of the plateau province are affected in various places by three types of structural deformation: (1) persistent, sharply defined monoclinal folds, (2) localized steep arching in association with laccolithic igneous intrusion, and (3) faults. The monoclinal folds exhibit an axial trend which is dominantly north- south, and in practically all cases the inclination of the steep limb of the fold is to the east. The dip in this direction averages about 40 degrees, but ranges locally to 70 degrees. From the crest of such a fold the strata are commonly very gently inclined to the west. The structures are therefore very asym- metrical anticlines. The rocks involved in this type of deformation range in age up to the youngest Cretaceous of the region, but do not include any of the Tertiary (Eocene) formations. From the fact that some of these folds, as beneath Aquarius Plateau, in southern Utah, and in the Chuska Mountains of northeastern Arizona, were truncated by erosion before burial by the earliest Tertiary of the region, it appears that the age of the folding is post-Cretaceous and pre-Tertiary. The deformation associated with the laccolithic intrusions consists of sharp upturning and arching of the strata immediately adjacent to the intrusion. Upper Cretaceous beds are involved in this disturbance, but in no case have ABSTRACTS OF PAPERS 89 Tertiary deposits been found in areas affected by the laccoliths. Except that the intrusions and accompanying deformation followed most of the Cretaceous, it is not possible definitely to determine the age relations of the movement. The faults, like the monoclinal flexures, have a predominant north-south trend. They are of the normal type, with the downthrow persistently to the “west. The displacements are comparable in size to the monoclines, involving movements with a vertical component ranging from a few hundred to more than two thousand feet. In all cases observed, these faults are more recent than the Tertiary formations of the region, and they belong, therefore, to a different chapter in the history of the province than the monoclines. Analysis of the monoclinal structures indicates that the displacement in- volved has been dominantly vertical rather than horizontal, but the presence of horizontal compressive stresses at the time of the deformation is indicated by the occurrence of some lateral movement and by the fact that the adjust- ment to the stresses was accomplished by folding rather than faulting. On the other hand, the forces which produced the large faults at a subsequent epoch appear to have been of a tensional nature. Instead of being squeezed together, blocks of the plateau tended to pull apart, one slipping downward on another. Both types of deformation are probably a response to isostatic adjustments, but in the one case horizontal compression, in the other tension, appears to modify the structural expression of the vertical stresses. The deformation associated with the laccolithic intrusions is evidently caused by the forces producing the intrusion. Presented in abstract extemporaneously. Brief remarks were made by Prof. A. C. Lawson. STRUCTURE OF THE SPRING MOUNTAIN RANGE, SOUTHERN NEVADA BY D. F. HEWETT (Abstract) Spring Mountain is a crescentic range, convex toward the northeast, about 75 miles long, in southern Nevada, west of Las Vegas. The highest point, Charleston Peak, 11,910 feet high, rises nearly 10,000 feet above the nearby valleys. Detailed mapping of the southern third of the range during 1921-22 yields the following conclusions: The section exposed ranges from the lower part of the Upper Cambrian to the Jurassic. The Cambrian, Devonian, Missis- sippian, and Pennsylvanian sections include about 6,500 feet of dolomite and limestone with traces of shale and sandstone. The Permian, Triassic, and Jurassic sections include 1,000 feet of red and buff sandstone, 400 feet of lime- stone, 50 feet of red shale, 600 feet of thin-bedded limestone, 1,000 feet of red shaly sandstone, and 2,200 feet of buff sandstone. In late Cretaceous time (7) the beds were gently folded along axes trending west of north; then three distinct blocks were successively thrust from the southwest. The lowest thrust is the flattest, the dip ranging from 9 degrees to 15 degrees; the higher thrusts are steeper. In each block there are local steep thrusts with small displacement. The thrust faults were closely followed by a group of early normal faults that trend north and dip west. Solutions 90) PROCEEDINGS OF THE ANN ARBOR MEETING bearing lead and zinc sulphides were introduced along the early normal faults, and spread out in the Mississippian and lower Pennsylvanian limestones. When they were introduced the nearby limestones were extensively altered to dolomite. Later (middle Tertiary?) a second system of normal faults of northwest trend and northeast dip broke the early faults and ore bodies. Finally, in late Tertiary time, there were sporadic normal faults of small dis- placement. The present range is not limited by normal faults and it is therefore not a fault-block range. The poorly defined scarp that forms the eastern front is due to erosion acting on the relatively soft Jurassic sandstone which underlies the Cambrian dolomite thrust upon it. Potosi Peak (8,504 feet), the highest peak in the southern part of the range, coincides with a large thrust block and is limited northeastward by a late normal fault. Presented in full extemporaneously. Brief remarks were made by Messrs. Hill and Lawson, with reply by the author. PLEISTOCENE OF NORTHWESTERN ILLINOIS: A GRAPHIC PRESENTATION OF SOME OF THE CHIEF LINES OF EVIDENCE BY MORRIS M. LEIGHTON (Abstract) A map of northwestern Illinois will be presented which will show (1) the distribution of the known occurrences of gumbotil, (2) old soils separating the loess and the till. (8) weathered till beneath unweathered loess, and (4) unweathered till beneath unweathered loess. Graphs will also be used to show the depths of leaching found in the different drift areas of northwestern I]li- nois and also in the Iowan drift area of northeastern Iowa. The direction from which the ice came and the resultant changes in drainage, involving the cutting of the Mississippi River gorge at Cordova, will be dealt with. Presented in full extemporaneously. Brief remarks were made by Mr. Leverett, with reply by the author. FOSSILIFEROUS LOESS BENEATH TILTED GALENA DOLOMITE AT THE BORDER OF THE BELVIDERE LOBE, IN NORTHWESTERN ILLINOIS BY MORRIS M. LEIGHTON (Abstract) During the past field season an exposure in Winnebago County, Illinois, was found which shows tilted Galena dolomite over fossiliferous loess. The fossils of the loess are badly crushed, but four distinct species were found, indicating a considerable fauna. Curator Frank C. Baker, of the University of Illinois Museum, pronounces them of early Peorian aspect. The position of the Galena dolomite is such as to indicate glacial ice-shove. The exposure is situated at the border of the Belvidere lobe, which the author previously referred to the early Wisconsin stage. Read by title. ABSTRACTS OF PAPERS QO] LATE TERTIARY AND PLEISTOCENE TERRACE PLAINS OF THE MIDDLE ATLANTIC COASTAL PLAIN BY CHESTER K. WENTWORTH * (Abstract) The terraces and associated formations of the middle Atlantic Coastal Plain and adjacent parts of the Piedmont Plateau are mainly of fluviatile and sub- ordinately of marine origin. In the basin of the Potomac River there are six in number, which may practicably be mapped as follows: Tenley, Brandywine, Sunderland, “C’ (Wicomico of Shattuck), “B” (Talbot of Shattuck in part), and “A” (Talbot of Shattuck in part). The two earlier are wholly fluviatile as far eastward as the present coast; the latter four are fluviatile in the west- ern part of their area and marine in the area adjacent to the coast. The present inclination of the terrace plains is to a large extent the original slope of deposition and is due only subordinately to crustal deformation. Fluviatile and marine portions of the terraces are separated by rather abrupt changes in inclination, which are not duplicated in the attitudes of higher and older terraces in the vicinity. The problems of correlation of plains are still far from solution for the whole coastal area, but the distribution of the glacial boulders and of other unique lithologic constituents of certain of the formations in the area studied most in detail promises to be of great value, as broader areas to the north and south are studied with closer attention to physical and lithologic characters than these have received in the past. The clear identification of the early Pleistocene Sunderland terrace, as dis- tinct from the present river grade to a point well into the Allegheny Plateau, is of great value in separating Pleistocene from probable pre-Pleistocene ter- race remnants, and by its comparison with later terraces this study joins with studies in other regions in demonstrating the very great duration of earlier Pleistocene epochs. Read by title. GLACIAL DEPOSITS OF MISSOURI AND ADJACENT DISTRICTS BY FRANK LEVERETT (Abstract) The Kansas drift forms a nearly continuous sheet, except where cut away in valleys about to the Missouri River in Missouri and the Kansas River in northeastern Kansas. South of these streams and also along the Mississippi below Hannibal, Mis- souri, and between the Mississippi and Illinois rivers in Pike and Calhoun counties, Illinois, there are scattered boulders and smaller erratics extending from 10 to 30 miles or more beyond the definite till sheet. These may repre- sent an earlier glaciation than the Kansan and be reduced on that account to a scanty deposit. The topographic situation is such that no ponding of waters + Introduced by A. C. Trowbridge. 9? PROCEEDINGS OF THE ANN ARBOR MEETING —_ outside the ice-sheet and resultant floating of erratics beyond the ice-border can be postulated. Some of the boulders are found on the highest divides, in situations where no land barrier could have ponded water outside the ice- border. Such is the case with boulders in high uplands south of Clinton, Kansas, and others near Tipton and Jefferson City, Missouri. Presented in full extemporaneously. GLACIAL DRAINAGE ON THE COLUMBIA PLATEAU OF WASHINGTON BY J. HARLEN BRETZ Presented in full extemporaneously. Brief remarks were made by Messrs. Leverett, Leighton, and Meinzer, with reply by the author. GLACIAL LAKE PROBLEMS BY GEORGE H. CHADWICK (Abstract) A discussion of some obscure features in the Laurentian Lake history, such as the probable outlet of Lake Wayne and its relation to Lake Vanuxem, with description of some hitherto unnoticed outlets and levels in New York State, and preliminary correlation charts as a basis for further work. Presented in full extemporaneously. Brief remarks were made by Mr. Leverett, with reply by the author. ICE ACTION ON INLAND LAKES BY IRVING D. SCOTT * (Abstract) ~The shove of ice on the shores of lakes of moderate size has been ascribed to both expansion of the ice during the winter and to wind-blown jams in the spring. The results of a study of the effects of these processes on the inland lakes of Michigan and a consideration of the relative effectiveness of the two processes will be presented in this paper. Read by title. BANDED POSTGLACIAL CLAY NEAR NEW YORK CITY BY CHESTER A. REEDS (Abstract) For two weeks during the month of September, 1922, yarve clay, similar to that described by De Geer, Lidén, and Antevs in Sweden, Sauramo in Finland, and De Geer and Antevs in America, was studied by the writer in the clay 1 Introduced by W. H. Hobbs. ABSTRACTS OF PAPERS 93 pit exposures in the Hackensack Valley at Little Ferry, New Jersey ; in glacial Lake Passaic at Mountain View and Morristown, New Jersey, and in the Hud- son River valley at Beacon, Dunnings Point, Brockway, and Roseton, New York. These studies were undertaken with the object of securing material for a museum exhibit on “Climates, Past and Present,” and incidentally to see what the possibilities were of applying De Geer’s methods of clay geochronology to the postglacial banded clays near New York City. The varve clay is present in all of the places mentioned above and there is no question but that the De Geer method of geochronology is applicable. Sec- tions were measured and considerable other data secured. The work of Anteyvs in the Connecticut River valley, ‘““The Recession of the Last Ice-sheet in New England,’ published by the American Geographical Society, November, 1922, shows what can be done in this direction in this section of the United States. Read by title. ORIGIN AND HISTORY OF EXTINCT LAKE CALVIN, IOWA BY WALTER H. SCHOEWE! (Abstract) Lake Calvin is an extinct glacial lake which was formed by the displace- ment of Mississippi River during the Illinoian stage of glaciation. The advanc- ing glacier in crossing into Iowa blocked the valley of Mississippi River and filled it with ice. This necessitated the finding of a new course to the west. The stream found an opening by way of the Maquoketa River valley and flowed first westward, then to the southward, through Goose Lake channel, to the valley of Wapsipinicon River, and finally, over the low divide between Mud and Elkhorn creeks, to the valley of the Cedar at Moscow; thence, con- tinuing southward to the junction of Iowa and Cedar rivers at Columbus Junction, the combined waters of the Mississippi, Maquoketa, Wapsipinicon, Cedar, and Iowa rivers and those flowing from the edge of the ice, found their pathway obstructed on the one side by the great ice-wall of the Illinoian ice- sheet and on the other by the Kansan bluffs, which stand 120 to 140 feet high. As the waters were unable to find an outlet, they rose and formed a vast and deep expanse of water, to which Udden gave the name “Lake Calvin.” During the long existence of the lake the surplus water found its way to the unfilled valley of the Mississippi below Fort Madison by way of an abandoned channel south of Columbus Junction. Field evidence in the form of lacustrine silts and clays, wave-rounded shore- lines, ice-rafted boulders, shingle or beach gravels, associated sandy shore de- posits, lake terraces, an inlet and an outlet, and a comparison of the relative widths of the Iowa and Cedar rivers within and without the lake basin—all point to the former existence of Lake Calvin. Lake Calvin existed to the time of the Iowan ice invasion. The long dura- tion of the lake is in complete harmony with the present-day conception re- garding the formation and origin of the gumbotils. It has been demonstrated by Kay that the formation of gumbotil is an exceedingly slow process. The 1JIntroduced by Dr. George IF’. Kay. 94 PROCEEDINGS OF THE ANN ARBOR MEETING Illinoian gumbotil, which is at least five feet thick, outcrops near the valley walls of the Iowa-Cedar River and along both sides of the Mississippi. Hence these two valleys are incised below the Illinoian upland plain and are post- Illinoian gumbotil in age. Therefore the lake could not have found its dis- charge by way of them, and the displaced Mississippi must have followed the course south of Columbus Junction until the lake was eventually drained by way of the Iowa-Cedar River valley. The thickness of the deposits in the lake basin, the well wave-rounded shorelines, and the relation of the contact be- tween the lake and the fluvial terrace all point to the same conclusion regard- ing the long duration of Lake Calvin. Due to stream piracy of the streams developed on the newly formed Illinoian drift plain after the formation of the gumbotil, Lake Calvin was eventually tapped and drained. Read by title. PHYSIOGRAPHY OF THE PARIA RIVER VALLEY, SOUTHERN UTAH BY RAYMOND C. MOORE (Abstract) Paria River is one of the main tributaries of the Colorado in southern Utah, its course trending south-southeast from the border of the high Tertiary pla- teaus to the head of Marble Canyon at Lees Ferry. The drainage basin of this stream exhibits physiographic relations which are typically representa- tive of a large part of the Colorado Plateau province. Essential factors in the shaping of land forms in the Paria Valley are the semi-arid climate, the character and structure of the rock formations, eleva- tion with respect to the master stream, and geologically recent changes in elevation. Annual precipitation is small, but the rains are torrential and the proportion of run-off is large. Canyons are a dominant topographic feature. The rocks consist of alternating hard and soft divisions which are in the main inclined to the north. About midway in its course the river crosses obliquely a steep-dipping monoclinal fold, along which are developed prominent hog- backs. A large north-south fault, with upthrow on the east, crosses the upper part of the drainage basin. The hard strata produce escarpments and hog- backs, the soft produce valleys and badlands. A difference in elevation of more than 7,000 feet exists between the headwaters of some of the tributaries and the mouth of the Paria. Analysis of the physiographic features of this interesting region permits recognition of at least two erosion cycles belonging to late Tertiary and recent geologic history, and, as noted by observers in some other parts of the plateau province, there is indication of displacement by faulting at more than one epoch. The plateau scarp west of the upper Paria Valley, which now has an elevation of more than 2,000 feet above the valley, is on the downthrown side of one of the large faults, the valley itself being in the upthrown block. Read by title. we) Or ABSTRACTS OF PAPERS SAND RIVERS OF TEXAS AND CALIFORNIA AND SOME OF THEIR ACCOMPANYING PHENOMENA BY ROBERT T. HILL (Abstract) (a) Certain rivers of the Great Plains region, interior deserts, and southern California constitute a class for which the name “sand rivers” is proposed. The Red River of Texas and the Santa Ana River of California are types. These are streams which deposit much of their sand load along their middle courses, to be subsequently removed by wind. (b) The “windrow” dunes of the Red River of Texas. On the south side of the Big Bend of Red River, in Wichita County, Texas, there are many elon- gated sand-dunes, occurring over a wide, normally dry, second bottom of the river and parallel to the stream. These are named “windrow dunes,’ owing to their resemblance to windrows of a hayfield, and they are described as one of the effects of disposition by the wind, after deposition on the sand flats, of the load of sand rivers. Presented in full extemporaneously. SEDIMENTATION AT THE MOUTHS OF THE MISSISSIPPI RIVER—PRELIMI- DY AUR NY (RIBTPOIRIE BY ARTHUR C. TROWBRIDGE (A dstract) Two months of field-work below New Orleans in 1922 yielded a number of notes. pertaining to (1) the flood of 1922, the highest water on record; (2) the relations of turbidity and total load to the maintenance of navigable chan- nels; (3) the gradual closing, by deposition, of some of the mouths of Pass a Loutre without permanently injuring South Pass; (4) the depth of the delta material; (5) the methods and rates of delta growth; (6) the constitution of the deposits on natural levees, in the passes, in the bays, and on the offshore bars; (7) recent enlargement of South Pass in relation to its navigability ; (S) the projected opening of Southwest Pass to navigation; (9) various other engineering projects in relation to sedimentation, etcetera. Read by title. GEOLOGICAL MAP OF THE BUSHVELD COMPLEX, TRANSVAAL, SOUTH AFRICA BY CHARLES PALACHE (Abstract) Exhibition of the map of the Bushveld Complex prepared by the Geological Survey of the Union of South Africa; explanation of some of the major fea- tures of the map; illustrations of structure and scenery of part of the region. Presented in abstract extemporaneously. 1 Paper presented by permission of the U. S. district engineer in New Orleans. 96 PROCEEDINGS OF THE ANN ARBOR MEETING TITLES AND ABSTRACTS OF PAPERS OF GROUP C AND DISCUSSIONS THEREON METAMORPHISM OF QUARTZITES BY THE BUSHVELD IGNEOUS COMPLEX BY FRED. E. WRIGHT (Abstract) In this preliminary paper the results of a field study of the changes produced in quartzites metamorphosed by invading magmas of the Bushveld igneous complex are given. The changes effected by granitic magmas are noticeably different from those produced by noritic magmas. Several series of specimens illustrating these differences, the formation of magmatites with abundant feldspar, on the one hand, the solution and recrystallization of the quartz grains to large individuals one to two inches across without the addition of much extraneous material on the other. The problems offered by these rocks can only be solved by combined field and laboratory study. This problem was selected as of the type suitable for attack by ‘the Geophysical Laboratory, where the development of experimental methods has now reached such a point that certain geological problems can be approached with some assurance of solution. Presented in abstract extemporaneously. FUSION OF SEDIMENTARY ROCKS IN DRILL-HOLES BY BAILEY WILLIS (Abstract) The paper discusses the conditions under which the drilling took place. Read by title. FUSION OF SEDIMENTARY ROCKS IN DRILL-HOLES BY N. L. BOWEN AND M. AUROUSSEAU Presented in abstract extemporaneously. Brief remarks were made by Dr. Sidney Powers. XENOLITHS IN THE STONY CREEK, CONNECTICUT, GRANITE BY JAMES F. KEMP Presented in abstract extemporaneously. DISCUSSION Prof. A. C. LANE: I would like to ask what causes the white halo around the xenolith? Professor Kemp: One often sees pegmatite structure more marked. In order to bring these out in contrast with stone, we have to sponge them with water. This may have brought about the white halo. I have not seen any develop- ment other than the coarser combinations of granite. ABSTRACTS OF PAPERS 97 NEW TEACHING DIAGRAM FOR IGNEOUS ROCKS BY A. B. VAN ESBROECK ? Read by title. AEROLITE FROM ROSE CITY, MICHIGAN BY EDMUND OTIS HOVEY (Abstract) A meteorite was seen to fall at 11 o’clock a. m. October 17, 1921, near Rose City. Ogemaw County, Michigan. Its path through the sky was from north- northwest to south-southeast. Three explosions were heard, but only three fragments, weighing together about 10,376 grams, have thus far been recoy- ered. The mass is composed of 17.25 per cent nickel iron and 82.75 per cent mineral matter, principally enstatite and olivine, with some anorthite. The structure is achondritic and agglomeratic. The chief additional feature of interest is the presence of abundant small miarolitic cavities in the mass, which are lined with minute crystals which seem to be of enstatite and olivine. Specific gravity of the finely pulverized material, 3.694. Presented in abstract extemporaneously. ORIGIN AND FORMATION OF CERTAIN APPALACHIAN BAUXITE DEPOSITS BY WILBUR A. NELSON Read in full from manuscript. Brief remarks were made by Messrs. Bonine and Lane. STORMBERG LAVAS OF SOUTH AFRICA BY FRED. E. WRIGHT (Abstract) The Stormberg basaltic lavas of South Africa, like the Deccan traps of India, the Snake River basalts of our Western States and of Patagonia, are of the so-called fissure eruption type and cover vast areas. The Stormberg region has been partly mapped geologically and topographically by Dr. A. L. du Toit. It was the writer’s good fortune to spend several weeks last July with Dr. du Toit in a field study of the Stormberg lavas with reference especially to the conditions of their eruption. The lavas are of Jurassic age and form great, nearly horizontal sheets, each flow maintaining throughout about the same characteristics and thickness. The total thickness of the series is approxi- mately a mile; the average thickness of a single flow is about 22 feet. Field evidence indicates that the lavas were highly liquid when they flowed over the land surface, that volcanic gases played a rdéle less obviously important than in ordinary eruptions of the central cone type. To solve the problems involved in ‘fissure eruptions, both field and laboratory work are essential if an even + Introduced by James F. Kemp. VII—BvULL. GEOL. Soc. Am., Von. 34, 1922 9S PROCEEDINGS OF THE ANN ARBOR MEETING approximately quantitative estimate of the importance of the several factors involved is to be made. Presented in abstract extemporaneously. DISCUSSION I. C. Wuite: I found the same series of lavas in a plateau in Brazil of thousands of square miles in extent and exhibiting great massive cliffs. A road that the Brazilians built up the cliffs’ to the great coal fields and the cattle country cost $1,000,000. It is simply a mule track cut up the sides of a huge cliff. The dikes from this great outflow penetrated the coal bed, and I traced a finger of dike along the immediate contact with the coal bed for 100 feet and found it had very little metamorphic influence on the coal. It had nearly as much volatile matter as original coal, but only touched the general metamorphic region. The lava was not very hot. The dike was only about 18 inches thick. The same series is found there as occurs in the Gunawanda? country, going over Cambrian? and the underlying Mesozoic beds. H. S. WASHINGTON: I might add a few words. There are two groups, one containing 48 and 49 per cent of silica, connected by very hard iron, about 14 to 13 per cent. Stormberg basalt contains about 52 per cent of silica and the other about 53% per cent. They are decidedly low in iron and the most silicious has only 9% per cent of iron and the other has only 8 per cent. Frep. E. WrIGHT: One very cleary sees that iron has very little to do with it and usually iron is only one factor that enters into the problem. It is char- acteristic of all basalt lavas that they came up with very little explosive action. Explosive action occurs chiefly in hydrous magmas. It seems to mé that iron with other basalts is one of the important factors; the other is the presence of gases which escaped on account of the high fluidity of the basalts. L. C. Graton: I gather from the reference to a colored top that it was some- what of a different composition than the other composition analyzed. Is that on account of retention of ferric ratio? If the lavas are in the attitude in which they were poured out, was there any slumping? With Dr. Wright's familiarity with Michigan lavas, would he say they are of the plateau type or would their slumping suggest somewhat different mechanism? Frep. E. Wricot: The color of the small flows is red, many times a very intense surface film of bright red. The ordinary lava flow coloration is not so intense. In regard to the slumping, there is a slight tendency toward slump- ing of several degrees toward the center of the basin which might be due to the weight. It is nearly horizontal. The point I made yesterday was in con- nection with the Keweenaw flows, where you have flow of uniform thickness and to a great extent almost subaerial and flows off on horizontal basis. It seems to me that Professor Kemp’s photographs yesterday were lava flows instead of lava sheets. One was low temperature and stiff, giving out gas, whereas plateau basalts welled out, came to rest, and, being thin, came to rest horizontally. , ABSTRACTS OF PAPERS 99 A HIGH TEMPERATURE VEIN IN MADISON COUNTY, MISSOURI BY W. A. TARR (Abstract) ~ A quartz vein cutting granite occurs in western Madison County, Missouri. The vein contains wolframite, fluorite, and zinnwaldite, indicating its forma- tion at high temperature; and also pyrite, sphalerite, galena, chalcopyrite, and arsenopyrite. Serpentine also occurs in the vein and offers an interesting problem as to its origin. Read by title. CRETACEOUS AGE AND EARLY EOCENE UPLIFT OF A PENEPLAIN IN THE SOUTHERN INTERIOR OF BRITISH COLUMBIA AND THE DEVELOP- MENT OF THE NORTH THOMPSON RIVER TRENCH BY W. L. UGLOW Read by title in absence of author. STUDY OF THE IGNEOUS ROCKS OF ITHACA, NEW YORK, AND VICINITY BY J. H. C. MARTENS * (Abstract) The dikes of basic igneous rocks in the Ithaca region occur in vertical north- south fissures which parallel the jointing of the Upper Devonian sediments— shales, sandstones, and limestones. They will be called dikes, whether the filling was originally entirely of magmatic origin or, as in some cases, largely composed of sedimentary fragments cemented by a matrix of igneous rock. Metamorphism of the sediments is very slight. The rock of these dikes is termed Kimberlite on account of the remarkable similarity of the fresher occurrences with the South African material. Both the micaceous and the mica-poor varieties noted in South Africa are repre- sented here. There are also intermediate facies. Striking similarities in minor mineralogical detail, such as anomalous pleochroism in mica, presence of garnet, etcetera, have also been noted. A chemical analysis of material from ‘one of the more micaceous dikes shows close analogy with the mica peridotite of Crittenden County, Kentucky, the alnoite of Mannheim, New York, and some of the South African micaceous Kimberlites. The significance of such peridotite dikes, occurring at many widely separated localities in the little-folded paleozoic rocks west of the Appalachians, is dis- cussed. The following papers were read in joint session with the Society of Economic Geologists: 1 Introduced by A. C. Gill. 100 PROCEEDINGS OF THE ANN ARBOR MEETING ATTEMPT TO STUDY THE ACTUAL CAPILLARY RELATIONSHIPS OF OIL AND WATER BY CHARLES W. COOK (Abstract) The theories concerning the importance of capillarity in causing the accu- mulation of petroleum have been based largely upon theoretical grounds and to a lesser extent upon experimental evidence. The experiments have been of such a nature that conclusions had to be drawn from what might be called the end results rather than from direct observation of the action. This paper describes the apparatus employed and the results obtained in an attempt to observe the actual relationships of oil and water while in contact and during migration. Presented in joint session with the Society of Economic Geologists. CHEMICAL SUGGESTIONS CONCERNING THE ORIGIN OF LAKE SUPERIOR COPPER ORES BY ROGER,C. WELLS (Abstract) A number of geologists believe that the copper in the conglomerate and amygdaloid lodes came to its present position in solutions which ascended from depth. The chemical possibilities which would accord with this view and known facts in this region are considered with special reference to the solution of copper and copper compounds by agents which might exist at depth and its deposition by agents which can be assumed to have been present nearer the surface. Presented in joint session with the Society of Economic Geologists. SOLVENTS AND PRECIPITANTS IN THE MICHIGAN COPPER LODES BY ALFRED C. LANE (Abstract) The paper discusses in some detail the relative importance of chlorides, carbonates, sulphates, and sulphides in solution, and the precipitation of the copper therefrom by ferrous salts, augite, magnetite, etcetera, or ferric salts, such as hematite and limonite, or hydrocarbons, and trap considered as an alkaline reducing agent. Presented in joint session with the Society of Economic Geologists. s REGISTER OF ANN ARBOR MEETING REGISTER OF THE ANN Arpor MEETING, 1922 F. J. Aucock ihe C. ALLEN Henry M. Ami GEORGE H. ASHLEY R.. M. Bace J. AUSTEN BANCROFT R. S. Basser ALAN M. BATEMAN W. S. BayLeEy CHARLES P. BERKEY N. L. BowrEn J. A. BOWNOCKER J. HARLEN BRETZ — T. M. BropErick Water H. BucHER EK. M. BurwasH GILBERT H. Capy J. ERNEST CARMAN Grorce H. CHADWICK Roun T. CHAMBERLIN JoHN M. CLARKE CHARLES W. Cook ie A. DALY EF. W. DE WoLFr Ricuarp E. DopGsE Cart O. DUNBAR Nevin M. FENNEMAN Aucust F. FOERSTE J. H. GARDNER ALBERT W. GILES CHarues N. GouLp U.S. GRANT L. C. GRATON Herspert EH. GREGORY Frank F. Grout JamMES H. Hance Roserr T. HiLu FELLOWS Wittram H. Hopss OuiveR B. Hopkins W. O. HotcHxiss EDMUND OTIs Hovey Water F. Hunt ELiswortH HUNTINGTON J Axe FRANK J. Katz ee AR acy: ARTHUR KEITH JAMES F. Kemp E. M. KInDLE Epwarp H. Kraus Henry B. KumMMEL ALFRED C. LANE Esper 8S. Larsen, JR. ANDREW C. Lawson W. T. Lee Morris M. LericHton CHarLes K. LEItH A. G. LEonNARD FRANK LEVERETT J. VotNrEy Lewis WALDEMAR LINDGREN W. N. Logan F. B. Loomis GEORGE D. LoupERBACK GrorcGE R. MANSFIELD GrorGce C. Martin Kirtitey F. Maruer Epwarp B. MatHews W. D. MattHew W. J. Murap O. E. MEINZER W. C. MENDENHALL W. J. Miner {4YMOND Moore 102 PROCEEDINGS OF THE ANN ARBOR MEETING Wiztpur A. NELSON A. C. TROWBRIDGE SIDNEY PAIGE W. H. TWENHOFEL CHARLES PALACHE J. A. UDDEN R. A. F. PENROSE, JR. K. O. ULRICH ALEXANDER H. PHILLIPS J. B. UMPLEBY SIDNEY POWERS Frank R. Van Horn TT; QUIRKE T. WAYLAND VAUGHAN Wittiam NortH RIcE A. C. VEATCH JoHN L. RicH CHESTER W. WASHBURNE RatpH W. RICHARDS Henry S. WASHINGTON CirarLes H. RicHARDSON THomas L. Watson HEINRICH RIES R. C. WELLS FREDERICK W. SARDESON Lewis G. WESTGATE T. HE. SAvaGe EpGar T. WHERRY CHARLES SCHUCHERT Davip WHITE A. EK. SEAMAN I. C. WHITE R. E. SoMErRsS BaiLtEy WILLIS J. K. SPURR Frep. E. WRIGHT CORRESPONDENT EMMANUEL DE MARGERIE FELLOWS-ELECT Victor DoLMAGE ALEXANDER W. McCoy In addition to the foregoing, there were registered at the meeting 117 members of affiliated societies and visitors. REFERENCE TO CONSTITUTION AND By-Laws The Constitution and By-Laws of the Society were published last year, in volume 33, number 1, pages 162-172. In view of the fact that no changes have been made, it is considered permissible to avoid reprinting in this number. They will be included again in the volume for 1924. OFFICERS, CORRESPONDENTS, AND FELLOWS OF THE GEOLOGICAL SOCIETY OF AMERICA OFFICERS FOR 1923 President: Davin Wuitet, Washington, D. C. Vice-Presidents: Witt1am H. Hopss, Ann Arbor, Mich. Wittiam H. Emmons, Minneapolis, Minn. T. WAYLAND VauGHAN, Washington, D. C. Epe@ar T. WHERRY, Washington, D. C. m Secretary: CHARLES P. BrrKry, New York, N. Y. Treasurer: Epwarp B. MatHews, Baltimore, Md. EHditor: J. STANLEY-Brown, 26 Exchange Place, New York, N. Y. Councilors: (Term expires 1923) LL. C. Graton, Cambridge, Mass. _G. D. Loupersacn, Berkeley, Calif. ‘(Term expires 1924) K. 5. Bastin, Chicago, Ill. L. G. Wesreatr, Delaware, Ohio (Term expires 1925) KpmMuND Otis Hovey, New York, N. Y. ALFRED H. Brooxs, Washington, D. C. (103) 104 PROCEEDINGS OF THE ANN ARBOR MEETING MEMBERSHIP, 1922 f CORRESPONDENTS BaRROIS, CHARLES, Lille, France. December, 1909. BroGceER, W. C., Christiania, Norway. December, 1909. CAPELLINI, GIOVANNI, Bologna, Italy. December, 1910. DE GEER, BARON GERHARD, Stockholm, Sweden. December, 1910. Dr MarGERIE, EMMANUEL, Strasbourg, Alsace, France. December, 1921. GEIKIE, SIR ARCHIBALD, Hasslemere, England. December, 1909. Heim, ALBERT, Ziirich, Switzerland. December, 1909. KAYSER, EMANUEL, Marburg, Germany. December, 1909. KiL1an, W., Grenoble, France. December, 1912. TEALL, J. J. H., London, England. December, 1912. TIETZE, Emit, Vienna, Austria. December, 1910. FELLOWS * Indicates Original Fellows (see article III of Constitution) ABBE, CLEVELAND, JR., College of the City of New York, New York, N. Y. August, 1899. ADAMS, FRANK Dawson, McGill University, Montreal, Canada. Dec., 1889. ADAMS, GEORGE I., University of Alabama, Tuscaloosa, Ala. December, 1902. ApAMS, LEASON H., Geophysical Laboratory, Washington, D. C. Dec., 1922. ADKINS, WALTER S., Apartado 150, Tampico, Tamaulipas, Mexico. Dec., 1921. Atcock, F. J., Geological Survey of Canada, Ottawa, Canada. Dec., 1920. ALDEN, WILLIAM C., U. S. Geological Survey, Washington, D. C. Dec., 1909. ALDRICH, TRUMAN H., 1026 Glen Iris Ave., Birmingham, Ala. May, 1889. ALLAN, JOHN A., Univ. of Alberta, Edmonton, Alberta, Canada. Dec., 1914. ALLEN, EUGENE T., Geophysical Laboratory, Washington, D. C. Dec., 1922. ALLEN, R. C., 1001 Kirby Building, Cleveland, Ohio. December, 1911. ALLING, H. L., University of Rochester, Rochester, N. Y. December, 1920. AMI, Henry M., Victoria Museum, Room 105, Ottawa, Canada. Dec., 1889. ANDERSON, FRANK M., State Mining Bureau, 2604 Aetna St., Berkeley, Calif. December, 1902. ANDERSON, Rospert V., Menlo Park, Calif. December, 1911. ANDREWS, E. C., Geol. Surv. of N. 8S. W., Sydney, N. S. Wales. Dec., 1920. ARNOLD, RALPH, 639 South Spring St., Los Angeles, Calif. December, 1904. ASHLEY, GEORGE HALL, State Capitol, Harrisburg, Pa. August, 1895. ATWOOD, WALLACE WALTER, Clark University, Worcester, Mass. Dec., 1909. Bace, Rurus MATHER, JR., 7 Brokaw Place, Appleton, Wis. December, 1896. Bain, H. Foster, 1430 33d St. N. W., Washington, D. C. December, 1895. BAKER, MANLEY BENSON, School of Mining, Kingston, Ontario. Dec., 1911. BALDWIN, S. PRENTISS, 11025 East Boulevard, Cleveland, Ohio. August, 1895. BALi, SYDNEY H., 42 Broadway, New York City. December, 1905. BANCROFT, JOSEPH A., McGill University, Montreal, Canada. December, 1914. BARBOUR, ERWIN HINCKLEY, University of Nebraska, Lincoln, Neb. Dec., 1896. BarTON, Donatp C., Amerada Pet. Corp., Houston, Texas. December, 1921. BARTON, GEORGE H., Boston Society of Natural History, Boston, Mass. Au- gust, 1890. LIST OF FELLOWS 105 BartscH, PAuL, U. S. National Museum, Washington, D. C. December, 1917. Bascom, FLORENCE, Bryn Mawr College, Bryn Mawr, Pa. August, 1894. BASSLER, Ray SmiTH, U. S. National Museum, Washington, D. C. Dec., 1906. Bastin, Epson S., University of Chicago, Chicago, Ill. December, 1909. BATEMAN, ALAN Mara, Yale University, New Haven, Conn. December, 1916. ‘BAYLEY, WILLIAM S., University of Illinois, Urbana, Ill. December, 1888. BEEDE, JosHuA W., 200 S. Seneca Ave., Bartlesville, Okla. December, 1902. Benson, W. N., University of Otago, Dunedin, New Zealand. Dec., 1919. BERKEY, CHARLES P., Columbia University, New York, N. Y. August, 1901. Berry, EpwarD WILBER, Johns Hopkins University, Baltimore, Md. Dec., 1909. BEYER, SAMUEL WALKER, Iowa Agricultural College, Ames, Iowa. Dec., 1896. BILLINGSLEY, Pau, Anaconda Copper Mining Co., Portage, Wash. Dec., 1922. BLACKWELDER, Exiot, Leland Stanford Jr. University, Stanford University, Calif. December, 1908. BoutTWELL, JoHN M., Natl. Copper Bank, Salt Lake City, Utah. Dec., 1905. BowEN, CHARLES F., c/o Standard Oil Co., 26 Broadway, New York City. December, 1916. Bowen, N. L., Geophysical Laboratory, Washington, D. ©. December, 1917. Bowlr, WILLIAM, U. S. Coast and Geodetic Survey, Washington, D. C. December, 1919. BoWNOCKER, JOHN ADAMS, Ohio State University, Columbus, Ohio. Dec., 1904. Branson, Epwin BAYER, University of Missouri, Columbia, Mo. -Dec., 1911. BretTz, J. H., University of Chicago, Chicago, Ill. December, 1917. BriGHAM, ALBERT PERRY, Colgate University, Hamilton, N. Y. December, 1893. Brock, REGINALD W., Univ. of British Columbia, Vancouver, B.C. Dec., 1904. Broperick, T. MontTerirH, Calumet and Hecla Mining Co., Calumet, Mich. December, 1921. Brokaw, A. D., 157 Maplewood Ave., Maplewood, N. J. December, 1920. Brooks, ALFRED HULSE, U. S. Geological Survey, Washington, D.C. Aug., 1899. Brown, BarnuM, American Museum of Natural History, New York, N. Y. December, 1910. BrRowN, CHARLES WILSON, Brown University, Providence, R. I. Dec., 1908. Brown, JOHN StrarrorD, U. 8S. Geol. Survey, Washington, D. C. Dec., 1922. Brown, THOMAS CLAcHAR, Laurel Bank Farm, Fitchburg, Mass. Dec., 1915. Bruce, E. L., Geological Survey of Candda, Ottawa, Canada. Dec., 1920. Bryan, Kirk, U. 8S. Geological Survey, Washington, D. C. December, 1922. BucHer, W. H., University of Cincinnati, Cincinnati, Ohio. December, 1920. BuppINGTON, A. F., 124 Pyne Hall, Princeton, N. J. December, 1919.: BUEHLER, HENRY ANDREW, Rolla, Mo. December, 1909. BurcHArD, E. F., U. S. Geological Survey, Washington, D. C. December, 1920. Burtine, LANcAsTER D., Whitehall Petr. Corp., 53 Parliament St., Westmin- ster, S. W. I., London, England. December, 1917. BuRWASH, Epwarp M. J., 556 Bathurst St., Toronto, Canada. Dec., 1916. BuTLER, BERT S., Box 277, Calumet, Mich. December, 1912. BuTLER, G. MonTAGUE, College of Mines, Tucson, Arizona. December, 1911. Butts, CHARLES, U. 8S. Geological Survey, Washington, D. C. December, 1912. Buwa.pa, J. P., University of California, Berkeley, Calif. December, 1920. Cavy, G. H., Fayetteville, Ark. December, 1920. CALHOUN, FRED HAarvEY HALL, Clemson College, S. C. December, 1909. 106 PROCEEDINGS OF THE ANN ARBOR MEETING CALKINS, FrANK C., U. S. Geological Survey, Washington, D. C. Dec, 1914. CAMPBELL, HENRY D., Washington and Lee Univ., Lexington, Va. May, 1889. CAMPBELL, MarRIus R., U. S. Geological Survey, Washington, D. C. Aug., 1892. Campos, Luiz FILIPPE G. DE, Geological Survey of Brazil, Rio de Janeiro, Brazil. December, 1917. . CAMSELL, CHARLES, Department of Mines, Ottawa, Canada. December, 1914. Capps, STEPHEN R., JR., U. S. Geological Survey, Washington, D.C. Dec., 1911. CARMAN, J. ERNEST, Ohio State University, Columbus, Ohio. December, 1917. CARNEY, FRANK, Box 309, Eldorado, Kans. December, 1908. CASE, ERMINE C., University of Michigan, Ann Arbor, Mich. December, 1901. | CHADWICK, GEORGE H., University of Rochester, Rochester, N. Y. Dec., 1911. CHAMBERLIN, ROLLIN T., University of Chicago, Chicago, Ill. December, 1913. *CHAMBERLIN, T. C., University of Chicago, Chicago, II. . CLAPP, CHARLES H., State University, Missoula, Mont. December, 1914. CLAPP, FREDERICK G., 30 Church St., New York City. December, 1905. CLARK, BrucE L., Bacon Hall, Univ. of California, Berkeley, Calif. Dec., 1918. CLARK, F. R., U. S. Geological Survey, Washington, D. C. December, 1919. CLARK, W. O., Pahala, Kau, Hawaii. December, 1920. CLARKE, JOHN Mason, Education Building, Albany, N. Y. December, 1897. CLELAND, HERDMAN F., Williams College, Williamstown, Mass. Dec., 1905. CLEMENTS, J. Morcan, 20 Broad St., New York City. December, 1894. Cops, CoLLiER, University of North Carolina, Chapel Hill, N. C. Dec., 1894. CoLEMAN, ARTHUR P., Toronto University, Toronto, Canada. December, 1896. CoLLIE, GEORGE L., Beloit College, Beloit, Wis. December, 1897. CoLLINs, WILLIAM H., Geological Survey, Ottawa, Canada. December, 1921. CoLLieR, ARTHUR J., U. S. Geological Survey, Washington, D. C. June, 1902. -Conpit, D. DALE, c/o Alliance Bank, Calcutta, India. December, 1916. Cook, CHARLES W., University of Michigan, Ann Arbor, Mich. Dec.; 1915. CooKE, C. WYTHE, U. S. Geological Survey, Washington, D. C. Dec., 1918. CostTE, EUGENE, 622 Dallas County State Bank Bldg., Dallas, Texas. Dec., 1906. CRAWFORD, RALPH Dixon, 1050 Tenth St., Boulder, Colo. December, 1916. Crook, ALJA R., State Museum of Natural History, Springfield, IJ. Dec., 1898. *CrOSBY, WILLIAM O., Massachusetts Institute of Technology, Boston, Mass. Cross, WHITMAN, 101 East Kirke St., Chevy Chase, Md. May, 1889. CULVER, GARRY E., 310 Center Ave., Stevens Point, Wis. December, 1891. CuMINGS, Epcar R., Indiana University, Bloomington, Ind. August, 1901. CUSHMAN, J. A., Sharon, Mass. December, 1919. DAKE, C. L., Missouri School of Mines, Rolla, Mo. December, 1920. Daz, N. C., Hamilton College, Clinton, N. Y. December, 1920. Day, RecGInALD A., Harvard University, Cambridge, Mass. December, 1905. DaNA, EDWARD SALISBURY, Yale University, New Haven, Conn. Dec., 1908. *DartToN, NELSON H., U. S. Geological Survey, Washington, D. C. Davis, E. F., 348 Sansome St., San Francisco, Calif. December, 1920. *DAvIsS, WILLIAM M., 31 Hawthorne St., Cambridge, Mass. Day, ARTHUR LovuIs, Geophysical Laboratory, Washington, D. C. Dec., 1909. Day, Davin T., 13833 F St. N. W., Washington, D. C. August, 1891. DEAN, BasHFoRD, Columbia University, New York, N. Y. December, 1910. De Goryer, E. L., 65 Broadway, New York, N. Y. December, 1918. DEUSSEN, ALEXANDER, 504 Stewart Bldg., Houston, Texas. December, 1916. LIST OF FELLOWS 107 De Wo tr, Frank W., Great Southern Life Bldg., Dallas, Texas. Dec., 1909. DICKERSON, Roy E., Masonic Temple Building, Manila, P. I. December, 1918. *DILLER, JOSEPH S., U. S. Geological Survey, Washington, D. C. D INVILLIERS, Epwarp V., 518 Walnut St., Philadelphia, Pa. December, 1888. DopeéEr, Ricu arp E., Storrs, Conn: August, 1897. DoLMAGE, Victor, Canadian Geological Survey, Ottawa, Canada. Dec., 1922. DRAKE, NoAu Frexps, Fayetteville, Arkansas. December, 1898. DRESSER, JOHN A., 701 Eastern Townships Bank Bldg., Montreal, Canada. December, 1906. *DUMBLE, EDWIN T., 316 Pacific Bldg., Houston, Texas. DunBar, C. O., Yale University, New Haven, Conn. December, 1920. BHAKLE, ARTHUR S., University of California, Berkeley, Calif. December, 1899. ECKEL,' HpwIN C., 1503 Decatur St. N. W., Washington, D. C. Dec., 1905. EMERY, WILSON B., Casper, Wyoming. December, 1919. *HMERSON, BENJAMIN K., Amherst, Mass. EmMMoNns, WILLIAM H., Univ. of Minnesota, Minneapolis, Minn. Dec., 1912. *FAIRCHILD, HERMAN L., University of Rochester, Rochester, N. Y. FARRINGTON, OLIVER C., Field Museum of Natural History, Chicago, Ill. De- cember, 1895. FatuH, A. ., U. S. Geological Survey, Washington, D. C. December, 1920. FENNEMAN, NEVIN M., University of Cincinnati, Cincinnati, Ohio. Dec., 1904. FENNER, CLARENCE N., Geophysical Laboratory, Washington, D. C. Dec., 1911. Frerevuson, H. G., U. S. Geological Survey, Washington, D.C. December, 1920. FisHER, Cassius Asa, 705 First Natl. Bank Bldg., Denver, Colo. Dec., 1908. ForrstE, Aucust F., 129 Wroe Ave., Dayton, Ohio. December, 1899. Forp, WiLl1AM H., Sheffield Scientific School, New Haven, Conn. Dec., 1915. Foyt, W. G., Wesleyan University, Middletown, Conn. December, 1919. FuLuer, Myron L., 60 Main St., Brockton, Mass. December, 1898. GALLOWAY, J. J., Columbia University, New York, N. Y. December, 1920. GALPIN, SIDNEY L., 630 Park Ave., Ames, Iowa. December, 1917. GANE, HENRY STEWART, R. D. No. 1, Santa Barbara, Calif. December, 1896. GARDNER, JAMES H., 626 Kennedy Building, Tulsa, Okla. December, 1911. GARDNER, JULIA A., U. S. Geological Survey, Washington, D. C. Dec., 1920. GEORGE, RUSSELL D., University of Colorado, Boulder, Colo. December, 1906. GIDLEY, JAMES WILLIAM, U. S. Nat'l] Museum, Washington, D. C. Dee., 1922. ILES, ALBERT W., University of Virginia, University, Va. December, 1921. GILL, ADAM CAPEN, Cornell University, Ithaca, N. Y. December, 1888. GLENN, L. C., 2111 Garland Ave., Nashville, Tenn. June, 1900. GoLpMAN, Marcus Isaac, U. 8S. Geol. Survey, Washington, D. C. Dec.. 1916. GOLDRING, WINIFRED, New York State Museum, Albany, N. Y. Dec., 1921. GOLDTHWAIT, JAMES WALTER, Dartmouth College, Hanover, N. H. Dec., 1909. GorpON, CHARLES H., University Library, University of Tennessee, Knoxville, Tenn. August, 18938. GorDON, CLARENCE E., Massachusetts Agricultural College, Amherst, Mass. December, 1918. GOULD, CHARLES N., 1218 Colcord Bldg., Oklahoma City, Okla. Dec., 1904. GRABAU, AMADEUS W., Government University, Peking, China. Dec., 1898. GRANGER, WALTER, American Museum of Natural History, New York, N. Y. December, 1911. 108 PROCEEDINGS OF THE ANN ARBOR MEETING GRANT, ULYSSES SHERMAN, Northwestern Univ., Evanston, Ill. Dec., 1890. GRASTY, JOHN SHARSHALL, Box 458, Charlottesville, Va. December, 1911. GRATON, Louis C., Foxcroft House, Cambridge, 38, Mass. December, 1913. GREGORY, HERBERT E., Yale University, New Haven, Conn. August, 1901. GREENE, FRANK Cook, 1434 S. Cincinnati Ave., Tulsa, Okla. December, 1917. GRIMSLEY, GEORGE P., 16 York Court, Baltimore, Md. August, 1895. Grout, FRANK F., University of Minnesota, Minneapolis, Minn. Dec., 1918. GURLEY, WILLIAM F. E. R., University of Chicago, Chicago, Ill. Dee., 1914. HALBERSTADT, Barrp, Pottsville, Pa. December, 1909. Hance, J. H., 708 W. Washington Boulevard, Urbana, Ill. December, 1920. Hancock, E. T., U. S. Geological Survey, Washington, D. C. December, 1919. Harper, E. C., 1111 Harrison Building, Philadelphia, Pa. December, 1918. Hares. C. J.. The Ohio Oil Co., Casper, Wyo. December, 1920. Harris, GILBERT D., Cornell University, Ithaca, N. Y. December, 1903. HARRISON, JOHN BURCHMORE, Georgetown, British Guiana. June, 1902. HARTNAGEL, CHRIS A., Education Building, Albany, N. Y. December, 1913. HASTINGS, JOHN B., 5456 Sierra Vista Ave., Los Angeles, Calif. May, 1889. *HAWORTH, ERASMUS, University of Kansas, Lawrence, Kans. Hay, OLIver F., Carnegie Institution, Washington, D. C. December, 1921. Hayes, ALBERT O., c/o Carr Bros., Ine., 65 Broadway, N. Y. City. Dec., 1919. HEALD, K. C., U. S. Geological Survey, Washington, D. C. December, 1920. HENNEN, Ray Y., 1604 Benedum-Trees Bldg., Pittsburgh, Pa. December, 1914. HERSHEY, Oscar H., Crocker Building, San Francisco, Calif. December, 1909. HEss, FRANK L., U. S. Geological Survey, Washington, D. C. December, 1921. HEWETT, DONNEL F., U. 8S. Geological Survey, Washington, D. C. Dec., 1916. Hick, RicHARD R., Beaver, Pa. December, 1903. Hii, J. M., U. S. Geological Survey, Washington, D. C. December, 1920. *HILL, RoBerT T., Room 816, Magnolia Bldg., Dallas, Texas. HiLts, RicHaArD C., Denver, Colo. August, 1894. Hinps, Henry, 1153 Laurel Ave., St. Paul, Minn. December, 1912. HINTZE, FERDINAND Friis, 580 Corona St., Denver, Colo. December, 1917. Hoses, WILLIAM H., University of Michigan, Ann Arbor, Mich. August, 1891. HOoLpEN, Roy J., Virginia Polytechnic Institute, Blacksburg, Va. Dec., 41914. HOLLAND, WILLIAM JaAcos, Carnegie Museum, Pittsburgh, Pa. December, 1910. HoLuick, ARTHUR, N. Y. Botanical Garden, New York, N. Y. August, 1898. Hopkins, O. B., International Petroleum Co., Ltd., 56 Church St.. Toronto, Canada. December, 1919. HopPKINS, THoMaAS C., Syracuse University, Syracuse, N. Y. December, 1894. HotcHKIss, WILLIAM Oris, State Geological Survey, Madison, Wis. Dec., 1911. *Hovey, EDMUND OTIs, American Museum of Natural History, New York, N. Y. Howe, ErRNEsT, Litchfield, Conn. December, 1903. HUBBARD, GEORGE D., Oberlin College, Oberlin, Ohio. December, 1914. Hupson, GeorGE H., Plattsburg Normal School, Plattsburg, N. Y. Dec., 1917. Hunt, WALTER F., University of Michigan, Ann Arbor, Mich. December, 1914. HUNTINGTON, ELLSworTH, Yale University, New Haven, Conn. Deec.. 1906. Hussakor, Louis, American Museum of Natural History, New York, N. Y. December, 1910. Hype, J. E., Western Reserve University, Cleveland, Ohio. December, 1916. JACKSON, ROBERT T., Peterborough, N. H. August, 1894. LIST OF FELLOWS 109 Jacosps, ELrsriwcGe C., University of Vermont, Burlington, Vt. December, 1921. JAGGAR, THOMAS AUGUSTUS, JR., Hawaiian Volcano Observatory, Territory of Hawaii, U. S. A. December, 1906. JEFFERSON, Mark S. W., Michigan State Normal College, Ypsilanti, Mich. De- cember, 1904. JEFFREY, EDWARD C., Harvard University, Cambridge, Mass. December, 1914. JENKINS, Ouar P., State College, Pullman, Wash. December, 1921. JOHANNSEN, ALBERT, University of Chicago, Chicago, Ill. December, 1908. Jounson, B. L., U. S. Geological Survey, Washington, D. C. December, 1919. JOHNSON, DouGLas WILSON, Columbia University, New York, N. Y. Dec., 1906. JoHuNSON, ROSWELL H., University of Pittsburgh, Pittsburgh, Pa. Dec., 1918. Jonas, ANNA L., Bridgeton, N. J. December, 1922. Katz, FRANK JAMES, U. S. Geological Survey, Washington, D. C. Dec., 1912. Kay, GEORGE FREDERICK, State Univ. of Iowa, Iowa City, Iowa. Dec., 1908. KEITH, ARTHUR, U. S. Geological Survey, Washington, D. C. May, 1889. *KEMP, JAMES F., Columbia University, New York, N. Y. Kew, W. S. W., 901 S. Norton Ave., Los Angeles, Calif. December, 1920. KEYES, CHARLES Ro.tuin, 944 Fifth St., Des Moines, Iowa. August, 1890. KINDLE, EpwarD M., Victoria Memorial Museum, Ottawa, Canada. Dec., 1905. Kirk, CHARLES T., Box 1592, Tulsa, Okla. December, 1915. Kirk, Epwin, U. S. Geological Survey, Washington, D. C. December, 1912. KNIGHT, CYyRIL WORKMAN, Toronto, Ontario, Canada. December, 1911. Knorr, ADOLPH, Yale Station, New Haven, Conn. December, 1911. Knorr, ELEANORA BLIss, 105 East Rock Road, New Haven, Conn. Dec., 1919. KNOWLTON, FRANK H., U. S. National Museum, Washington, D. C. May, 1889. Kraus, Epwarp HEnry, University of Michigan, Ann Arbor, Mich. June, 1902. KUMMEL, HENRY B., Trenton, N. J. December, 1895. *Kunz, GEORGE F., 401 Fifth Ave., New York, N. Y. LAHEE, FREDERIC H., Sun Co., Dallas, Texas. December, 1917. LANDES, HENRY, University of Washington, University Station, Seattle, Wash. December, 1908. LANE, ALFRED C., Tufts College, Mass. December, 1889. LARSEN, ESpER S., JR., U. S. Geological Survey, Washington, D.C. Dec., 1914. Lawson, ANDREW C., University of California, Berkeley, Cal. May, 1889. LEE, WILLIS THomMaASs, U. S. Geological Survey, Washington, D. C. Dec., 1903. LEES, JAMES H., Iowa Geological Survey, Des Moines, Iowa. December, 1914. LEIGHTON, Morris M., University of Illinois, Urbana, Ill. December, 1921. LreITH, CHARLES K., University of Wisconsin, Madison, Wis. Dec., 1902. LEONARD, ARTHUR G., State University of North Dakota, Grand Forks, N. Dak. December, 1901. LEVERETT, FRANK, Ann Arbor, Mich. August, 1890. LEwIis, J. VoLNEY, Rutgers College, New Brunswick, N. J. December, 1906. LIBBEY, WILLIAM, Princeton University, Princeton, N. J. August, 1899. LippL£, R. A., Standard Oil Company of Venezuela, Caracas, Venezuela, South America. December, 1921. LINDGREN, WALDEMAR, Massachusetts Institute of Technology, Cambridge, Mass. August, 1890. LisBoa, MIGUEL A. R., Caixa postal 829, Ave. Rio Branco 46-V, Rio de Janeiro, Brazil. December, 1918. 110 PROCEEDINGS OF THE ANN ARBOR MEETING LItTLE, Homer P., Clark University, Worcester, Mass. December, 1918. Luoyp, E. R., c/o Mid Kansas Oil and Gas Co., Mineral Wells, Texas. De- cember, 1919. LoGaN, WILLIAM N., Indiana University, Bloomington, Ind. December, 1917. Loomis, FREDERICK BREWSTER, Amherst College, Amherst, Mass. Dec., 1909. LOUDERBACK, GEORGE J)., University of California, Berkeley, Calif. June, 1902. LOUGHLIN, GERALD F., U. S. Geological Survey, Washington, D. C. Dec., 1916. Low, ALBERT P., 154 McLaren St., Ottawa, Canada. December, 1905. LULL, RICHARD SWANN, Yale University, New Haven, Conn. December, 1909. LUPTON, CHARLES T., 611 17th St., Denver, Colo. December, 1916. McCALligE, SAMUEL WASHINGTON, Atlanta, Ga. December, 1909. McCaskeEy, Hiram D., Central Point, Oregon. December, 1904. McConneELL, RIcHARD G., Ridean Club, Ottawa, Canada. May, 1889. McCoy, ALEXANDER WATTS, Bartlesville, Okla. December, 1922. MacDonatp, Donatp F., 45 Nassau St., New York, N. Y. December, 1915. MACFARLANE, JAMES RIEMAN, Woodland Road, Pittsburgh, Pa. August, 1891. McINNES, WILLIAM, Geological and Natural History Survey of Canada, Ot- tawa, Canada. May, 1889. MacKay, BERTRAM REID, Geol. Survey of Canada, Ottawa, Canada. Dec., 1922. McKELLar, PETER, Fort William, Ontario, Canada. August, 1890. McLAvuGHLIIN, DonaALp H., 1629 Euclid Ave., Berkeley, Calif. December, 1922. MANSFIELD, GEORGE R., 2067 Park Rd., N. W., Washington, D. C. Dec., 1909. Marsut, Curtis F., Bureau of Soils, Washington, D. C. August, 1897. MARSTERS, VERNON F.,, 920 Grande Ave., Hayes Building, Kansas City, Mo. August, 1892. Martin, GEorGE C., U. S. Geological Survey, Washington, D. C. June, 1902. MartTIN, LAWRENCE, Dept. of State, Room 381, Washington, D. C. Dec., 1909. MaTHER, KirTLey F., Denison University, Granville, Ohio. December, 1918. MaturEws, Epwarp B., Johns Hopkins University, Baltimore, Md. Aug., 1895. Matson, GEorGE C., 408 Cosden Bldg., Tulsa, Okla. December, 1918. MatTrHes, Francois E., U. S. Geol. Survey, Washington, D. C. Dec., 1914. MatTrTrHew, W. D., American Museum of Natural History, New York. N. Y. December, 1903. Maury, CArLoTtTa J., Hastings-on-Hudson, N. Y. December, 1920. MAYNARD, THOMAS POOLE, 1622 D. Hurt Bldg., Atlanta, Ga. December, 1914. MEAD, WARREN JUDSON, University of Wisconsin, Madison, Wis. Dec., 1916. MEHL, Maurice G., University of Missouri, Columbia, Mo. December, 1922. MEINZER, Oscar E., U. S. Geological Survey, Washington, D. C. Dec., 1916. MENDENHALL, WALTER C., U. S. Geol. Survey, Washington, D. C. June, 1902. MERRIAM, JOHN C., Carnegie Institution, Washington, D. C. August, 1895. MERRILL, GEORGE P., U. S. National Museum, Washington, D. C. Dec., 1888. MERWIN, HERBERT E., Geophysical Laboratory, Washington, D. C. Dec., 1914. Mitter, ARTHUR M., State University of Kentucky, Lexington, Ky. Dec., 1897, MILLER, BENJAMIN L., Lehigh University, South Bethlehem, Pa. Dec., 1904. MILLER, WILLET G., Toronto, Canada. December, 1902. MILLER, WILLIAM JoHN. Smith College, Northampton, Mass. December, 1909. Miser, HueH D., U. S. Geological Survey, Washington, D. C. December, 1916. Morrit, Frep Howarp, U. 8S. Geological Survey, Washington, D.C. Dec., 1912. LIST OF FELLOWS ci MorencraAarF, G. A. F., Technical High School, Delft, Holland. Dec., 1913. Moox, CHARLES Craic, Metuchen, N. J. December, 1922. Moore, Exiwoop S., University of Toronto, Toronto, Canada. December, 1911. Moore, RayMonpD C., University of Kansas, Lawrence, Kans. December, 1921. Munn, Matco“mm JoHNn, Clinton Bldg., Tulsa, Okla. December, 1909. *Nason, FRANK L., West Haven, Conn. NELSoNn, W. A., Tennessee Geological Survey, Nashville, Tenn. Dec., 1920. NEWLAND, Davip Hate, Albany, N. Y. December, 1906. NE wsom, JoHN F., Leland Stanford, Jr., University, Stanford University, Calif. December, 1899. Nose, Levi F., Valyermo, Calif. December, 1916. Norton, WILLIAM H., Cornell College, Mount Vernon, Iowa. December, 1895. Norwoop, CHARLES J., State University, Lexington, Ky. August, 1894. O’CoNNELL, MargorrzE, American Museum of Natural History, New York, N. Y. December, 1919. Ocitvig, IpA HELEN, Barnard College, Columbia University, New York, N. Y. December, 1906. O’HarA, CLEOPHAS C., South Dakota School of Mines, Rapid City, S. Dak. December, 1904. OHERN, DANIEL WEBSTER, 515 W. 14th St., Oklahoma City, Okla. Dec., 1911. OLIVEIRA, E. P. DE, Geol. Survey of Brazil, Rio de Janeiro, Brazil. Dec., 1918. O'NEILL, J. J., Geological Survey of Canada, Ottawa, Canada. Dec., 1920. OSBORN, HENRY F., American Museum of Natural History, New York, N. Y. August, 1894. OVERBECK, RoBEerRT M., 834 Ocean Ave., Long Beach, Calif. December, 1921. Pack, Robert W., American Hxchange National Bank Bldg., Dallas, Texas. December, 1916. [’arce, SIDNEY, U. S. Geological Survey, Washington, D. C. December, 1911. VALACHE, CHARLES, Harvard University, Cambridge, Mass. August, 1897. PARKS, WILLIAM A., University of Toronto, Toronto, Canada. Dec., 1906. *PaTTON, HorAcE B., 3149 West 44th St., Denver, Colo. Peck, FREDERICK B., Lafayette College, Easton, Pa. August, 1901. PENROSE, RicHARD A. F., Jr., 460 Bullitt Bldg., Philadelphia, Pa. May, 1889. PERKINS, GEORGE H., University of Vermont, Burlington, Vt. June, 1902. PERRY, JOSEPH H., 276 Highland St., Worcester, Mass. December, 1888. PHALEN, WILLIAM C., The Solvay Process, Syracuse, N. Y. December, 1912. PHILLIPS, ALEXANDER H., Princeton University, Princeton, N. J. Dec., 1914. PoGuE, JOSEPH E., 42 West 12th St., New York, N. Y. December, 1911. Powers, SIpNEY, Amerada Petr. Co., P. O. Box 2022, Tulsa, Okla. Dec., 1920. PRAtT, JOSEPH H., North Carolina Geol. Survey, Chapel Hill, N.C. Dec., 1898. Pratt, W. E., Humble Oil and Refining Co., Houston, Texas. Dec., 1920. Price, WILLIAM A., Jr., 626 West Bldg., Houston, Texas. December, 1916. | PRINDLE, Louis M., U. S. Geological Survey, Washington, D. C. Dec., 1912. ProutTy, WILLIAM F., Univ. of North Carolina, Chapel Hill, N. C. Dec., 1911. *PUMPELLY, RAPHAEL, Newport, R. I. QUIRKE, TERENCE T., University of Illinois, Urbana, Ill. December, 1921. RANSOME, FREDERICK L., U. S. Geol. Survey, Washington, D. C. August, 1895. RAYMOND, PERCY Epwarp, Museum of Comparative Zodlogy, Cambridge, Mass. December, 1907. 112 PROCEEDINGS OF THE ANN ARBOR MEETING REEDS, CHESTER A., American Museum of Natural History, New York, N. Y. December, 1913. REESIDE, JOHN B., JR., U. S. Geological Survey, Hyattsville, Md. Dee., 1921. REGER, Davip B., Box 816, Morgantown, W. Va. December, 1918. REID, HARRY FIELDING, Johns Hopkins University, Baltimore, Md. Dec., 1892. REINECKE, LEOPOLD, C/o P. A. Williams, Loanda, Angola, S. W. Africa. De- cember, 1916. Rice, WILLIAM NortTH, Wesleyan University, Middletown, Conn. August, 1890. RicH, JOHN Lyon, P. O. Box 294, Iola, Kans. December, 1912. Ricuarps, R. W., U. 8S. Geological Survey, Washington, D.C. December, 1920. RICH ARDSON, CHARLES H., Syracuse University, Syracuse, N. Y. Dec., 1899. RICHARDSON, GEORGE B., U. 8S. Geol. Survey, Washington, D. C. Dec., 1908. Ries, HEINRICH, Cornell University, Ithaca, N. Y. December, 1893. Riccs, ELMER S., Field Museum of Natural History, Chicago, Ill.. Dec., 1911. RoBinson, HENRY HOLLISTER, Hopkins Hall, New Haven, Conn. Dec., 1916. Roppy, H. J., State Normal School, Millersville. Pa. December, 1919. RocerRs, AUSTIN F., Stanford University, Calif. December, 1918. RoseE, Bruce, Dept. of Geology, Queens Univ., Kingston, Ontario. Dec., 1916. RUEDEMANN, Rupo.r, Albany, N. Y. December, 1905. RUTLEDGE, JOHN J., 22 Light St., Baltimore, Md. December, 1911. SALES, RENo H., Anaconda Copper Mining Company, Butte, Mont. Dec., 1916. SAYLES, RoBERT WiLcox, Harvard University, Chestnut Hill, Mass. Dec., 1917. SARDESON, FREDERICK W., Uniy. of Minnesota, Minneapolis, Minn. Dec., 1892. SAVAGE, THOMAS EDMUND, University of Illinois, Urbana, Ill. December, 1907. ScH ALLER, WALDEMAR T., U. S. Geol. Survey, Washington, D. C. Dec., 1918. SCHOFIELD, 8. J., University of British Columbia, Vancouver, B.C. Dec., 1918. SCHRADER, FRANK C., U. S. Geological Survey, Washington, D. C. Aug., 1901. ScHUCHERT, CHARLES, Yale University, New Haven, Conn. August, 1895. ScHULTZ, ALFRED R., Hudson, Wis. December, 1912. Scott, WILLIAM B., Princeton University, Princeton, N. J. August, 1892. SEAMAN, ARTHUR E., Michigan College of Mines, Houghton, Mich. Dec., 1904. SELLARDS, EviAs H., University of Texas, Austin, Texas. December, 1905. SEMMES, DovucLtas R., Apartado Postal, 150 Tampico, Tamps, Mexico. De- cember, 1921. SHALER, MiI“LiarD K., 66 Rue Des Colonies, Brussels, Belgium. Dec., 1914. SHANNON, CHARLES W., Oklahoma Geol. Survey, Norman, Okla. Dec., 1918. SHATTUCK, GEORGE BURBANK, Poughkeepsie, N. Y. August, 1899. Saw, EvGENE W., 11 Taylor St., Chevy Chase, Md. December, 1912. SHEpDD, SoLon, State College of Washington, Pullman, Wash. December, 1904. SHEPARD, EDWARD M., 1403 Benton Ave., Springfield, Mo. August, 1901. SHIMEK, BOHUMIL, University of Iowa, lowa City, Iowa. December, 1904. SHIMER, HERVEY WoopsurRN, Massachusetts Institute of Technology, Cam- bridge, Mass. December, 1910. SHULER, E. W., South Methodist University, Dallas, Texas. December, 1920. SIEBENTHAL, CLAUDE E., U. S. Geol. Survey, Washington, D.C. Dec., 1912. *SIMONDS, FREDERICK W., University of Texas, Austin, Texas. SIncLaIR, WILLIAM JOHN, Princeton University, Princeton, N. J. Dec., 1906. SINGEWALD, JOSEPH T., Johns Hopkins University, Baltimore, Md. Dec., 1911. SLoAN, EarLe, Charleston, 8. C. December, 1908. LIST OF FELLOWS eles SmitH, BuRNETT, Syracuse University, Skaneateles, N. Y. December, 1911. SmiTH, Cari, Box 1136, Tulsa, Okla. December, 1912. *SmITH, EuGENE A., University of Alabama, University, Ala. SmiTH, GEORGE Otis, U. S. Geological Survey, Washington, D. C. Aug., 1897. SmiTH, Puiip S., U. S. Geological Survey, Washington, D. C. Dec., 1909. SmitH, RicHarpD A., Biological Survey of Michigan, Lansing, Mich. Dec., 1921. SmiTH, STANLEY, University, Bristol, England. December, 1922. SMITH, WARREN Du Prb&, University of Oregon, Eugene, Ore. December, 1909. Smiru, W. S. TanciEr, 640 Tennyson Ave., Palo Alto, Calif. June, 1902. *Smock, JOHN C., Hudson, N. Y. SmMyTH, CHARLES H., Jr., Princeton University, Princeton, N. J. Aug., 1892. SmyTH, Henry L., Harvard University, Cambridge, Mass. August, 1894. Somers, R. E., Oil and Gas Bldg., University of Pittsburgh, Pittsburgh, Pa. December, 1919. Soper, Epear K., 120 Broadway, New York City, Room 3101. December, 1918. SosMAN, R. B., Geophysical Laboratory, Washington, D. C. December, 1920. SPEIGHT, Ropert, Christ Church, Canterbury College, New Zealand. Dec., 1916. SPENCER, ARTHUR CoE, U.S. Geological Survey, Washington, D.C. Dec., 1896. SPRINGER, FRANK, U. S. National Museum, Washington, D.C. December, 1911. Spurr, JOSIAH E., c/o Engineering and Mining Journal, 10th Ave. and 36th St., New York, N. Y. December, 1894. STANLEY-BROWN, JOSEPH, 26 Hxchange Place, New York, N. Y. August, 1892. STANTON, TimMoTHY W., U.S. National Museum, Washington, D.C. Aug., 1891. STAUFFER, CLINTON R., Univ. of Minnesota, Minneapolis, Minn. Dec., 1911. STEBINGER, EUGENE, JR., 18 Broadway, New York, N. Y. December, 1916. STEIDTMANN, EDWARD, University of Wisconsin, Madison, Wis. Dec., 1916. STEPHENSON, LiLoyp W., U. S. Geol. Survey, Washington, D. C. Dec., 1911. *STEVENSON, JOHN J., 215 West 101st St., New York, N. Y. STOLLER, JAMES HouGH, Union College, Schenectady, N. Y. December, 1917 STONE, RALPH WALTER, State Geological Survey, Harrisburg, Pa. Dec., 1912. STOSE, GEORGE WILLIS, U. 8S. Geological Survey, Washington, D. C. Dec., 1908. Stout, WILBER, Geological Survey of Ohio, Columbus, Ohio. December, 1918. Swartz, CHARLES K., Johns Hopkins University, Baltimore, Md. Dec., 1908. TABER, STEPHEN, University of South Carolina, Columbia, 8S. C. Dec., 1914. Tarr, JOSEPH A., 781 Flood Building, San Francisco, Calif. August, 1895. TaLsoT, Mignon, Mount Holyoke College, South Hadley, Mass. Dec., 1913. TALMAGE, JAMES H., 47 E. So. Temple St., Salt Lake City, Utah. Dec., 1897. TarR, WILLIAM ARTHUR, University of Missouri, Columbia, Mo. Dec., 1917. TAYLOR, FRANK B., Fort Wayne, Ind. December, 1895. THOMAS, ABRAM O., University of Iowa, Iowa City, Iowa. December, 1921. TitTon, J. L., Morgantown, W. Va. December, 1920. TOMLINSON, CHARLES WELDON, 1610 Bixby Ave., Ardmore, Okla. Dec., 1917. TROWBRIDGE, ARTHUR C., University of Iowa, Iowa City, Iowa. Dec., 1913. *TURNER, HENRY W., Mills Building, San Francisco, Calif. TWENHOFEL, WILLIAM H., University of Wisconsin, Madison, Wis. Dec., 1913. TWITCHELL, MAYVILLE W., State Geological Survey, Trenton, N. J. Dec., 1911. TYRRELL, JOSEPH B., Confederation Life Bldg., Toronto, Canada. May, 1889. UppEN, JOHAN A., University of Texas, Austin, Texas. August, 1897. VITI—BuLL. Grou. Soc. AM., VoL. 34, 1922 114 | PROCEEDINGS OF THE ANN ARBOR MEETING Uctow, WittiamM L., University of British Columbia, Vancouver, Canada. December, 1922. UxricH, Epwarp O., U. S. Geological Survey, Washington, D. C. Dec., 1903. UMPLEBY, JOSEPH B., University of Oklahoma, Norman, Okla. Dec., 1913. *UPHAM, WARREN, Minnesota Historical Society, St. Paul, Minn. Van Horn, F. R., Case School of Applied Science, Cleveland, Ohio. - Dec., 1898. vAN INGEN, GILBERT, Princeton University, Princeton, N. J. December, 1904. Van Tuy, Francis M., Colorado School of Mines, Golden, Colo. Dee., 1917. VAUGHAN, T. WAYLAND, U. S. Geol. Survey, Washington, D. C. August, 1896. VEATCH, ARTHUR CLIFFORD, 7 Central Drive, Port Washington, N. Y. Decem- ber, 1906. WADE, Bruce, State Geological Survey, Nashville, Tenn. December, 1920. *WaLcoTT, CHARLES D., Smithsonian Institution, Washington, D. C. WALKER, THOMAS L., University of Toronto, Toronto, Canada. Dec., 1903. WARING, GERALD A., Port of Spain, Trinidad, B. W. I. December, 1921. WARREN, CHARLES H., Massachusetts Institute of Technology, Boston, Mass. Décember, 1901. WASHBURNE, C. W., 2 Rector St., New York, N. Y. December, 1919. WASHINGTON, HENRY STEPHENS, Geophysical Laboratory, Washington, D. C. August, 1896. Watson, THOMAS L., University of Virginia, Charlottesville, Va. June, 1900. WEAVER, CHARLES E., 264 Herkimer Road, Utica, N. Y. December, 1913. WEED, WALTER H., Tuckahoe, N. Y. May, 1889. WEGEMANN, CARROLL H., 722 East 7th Ave., Denver, Colo. December, 1912. WEIDMAN, SAMUEL, 814 Monett St., Norman, Okla. December, 1903. WELLER, STUART, University of Chicago, Chicago, Ill. June, 1900. WELLs, Rocer C., U. S. Geological Survey, Washington, D. C. Dec., 1921. WESTGATE, Lewis G., 124 Oak Hill Ave., Delaware, Ohio. August, 1894. WHerry, EpeGar T., Bureau of Chemistry, Washington, D. C. Dec., 1915. Wuite, Davin, U. S. National Museum, Washington, D. C. May, 1889. *WHITE, ISRAEL C., Morgantown, W. Va. WuHuittock, H. P., American Museum of Natural History, New York, N. Y. December, 1920. WIELAND, GEORGE REBER, Yale University, New Haven, Conn. December, 1910. WILDER, FRANK A., North Holston, Smyth County, Va. December, 1905. *WILLIAMS, Epwarp H., Jr., Woodstock, Vt. WILLIAMS, Ira A., Oregon Bureau of Mines and Geology, 417 Oregon ec Portland, Ore. December, 1905. WILLIAMS, MERTON YARWoOop, Geological Survey, Ottawa, Canada. Dec., 1916. Wiis, Barrey, Leland Stanford Jr. University, Stanford University. Calif. December, 1889. WILSON, ALFRED W. G., Department of Mines, Ottawa, Canada. June, 1902. Witson, Morey Evans, Geological Survey, Ottawa, Canada. December, 1916. WINCHELL, ALEXANDER N., University of Wisconsin, Madison, Wis. Aug., 1901. *WINCHELL, HORACE VAUGHAN, Pacific Mutual Building, Los Angeles, Calif. *WINSLOW, ARTHUR, 131 State St., Boston, Mass. Wotrr, JOHN E., Harvard University. Cambridge, Mass. December, 1889. Woop, Harry Oscar, Mt. Wilson Observatory, Pasadena, Calif. Dec., 1922 WoopMAN, JOSEPH E., New York University, New York, N. Y. Dec., 1905. LIST Oe FELLOWS 115 WooprInc, WENDELL P., U. S. Geol. Survey, Washington, D. C. Dec., 1921. Wooprvurr, HE. G., New England Oil and Pipe Co., Tulsa, Okla. Dec., 1922. Woopwarp, Roper S., Carnegie Institution, Washington, D. C. May, 1889. WoopwortH, Jay B., Geological Museum, 38 Oxford St., Cambridge, Mass. December, 1895. ~ WRIGHT, CHARLES WILL, 28 Vie del Parliamento, Rome, Italy. Dec., 1909. WRIGHT, FREDERIC E., Geophysical Laboratory, Carnegie Institution, Washing- ton, D. C. December, 1903. ZIEGLER, VicToR, Colorado School of Mines, Golden, Colo. December, 1916. CORRESPONDENTS DECEASED CREDNER, HERMAN. Died July 22, 1913. MicueEet-Livy, A. Died September, 1911. RoSENBUSCH, H. Died January 20, 1914. SUESS, Epwarp. Died April 20, 1914. TSCHERNYSCHEW,. TH. Died Jan. 15, 1914. ZIRKEL, FERDINAND, Died June 11, 1912. FELLOWS DECEASED * Indicates Original Fellow (see article III of Constitution) *ASHBURNER, CHAS. A. Died Dec. 24, 1889. BARLOW, ALFRED E. Died May 28, 1914. BARRELL, JOSEPH. Died May 4, 1919. BEECHER, CHARLES IW. Died Feb. 14, 1904, *Becker, GEORGE F. Died April 20, 1919 BELL, Rogert. Died June 18, 1917. BICKMORE, ALBERT S. Died Aug. 12, 1914. BLAKE, WM. PuHireps. Died May 21, 1910. BowMAN, Amos. Died June 18, 1894. BRANNER, JOHN C. Died March 1, 1922. Brown, AMOS P. Died Oct. 9, 1917. BUCKLEY, ERNEST R. Died Jan. 19, 1912. CaiRNES, D. D. Died June 14, 1917. *@ALVIN, SAMUEL. Died April 17, 1911. CARPENTER, FRANK R. Died April 1, 1910. *CHAPIN, J. H. Died March 14, 1892. CLARK, WILLIAM B. Died July 27, 1917. *CLAYPOLE, EDWARD W. Died Aug. 17, 1901. *CoMSTOCK, THEO. B. Died July 26, 1915. Cook, GrorGE H. Died Sept. 22, 1889. *Copr, EpwarD D. Died April 12, 1897. Cox, Guy H. Died August 20. 1922. CASTILLO, ANTONIO Dru. Died Oct.28,1895. *CUSHING, H. P. Died April 14, 1921. *DANA, JAMES D. Died April 14, 1895. Davis, CHARLES A. Died April 9, 1916. Dawson, GrorGh M. Died March 2, 1901. DAWSON, Sir J. WM. DERBY, ORVILLE A, DRYSDALE, CHAS. W. Died Nov. 27, 1915. Died July 10, 1917. DUTTON, CLARENCE FE. Died Jan. 4, 1912. *DwicHt, WM. B. Died Aug. 29, 1906. HASTMAN, CHAS. R. Died Sept. 27, 1918. *HLDRIDGE, GEORGE H. Died June 29, 1905. *HMMONS, SAMUEL FEF. Died March 28, 1911. FONTAINE, WM. M. *WRAZBER, PERSIFOR. Died April 7, 1909. *RULLER, HOMER T. Died Nov. 19, 1899. Died April 30, 1913. *RoOoTE, ALBERT EH. Died October 10, 1895. Died Aug. 14, 1908. *GILBERT, GROVE K. Died May 1, 1918. Giroux, N. J. Died November 30, 1891. HaAGurE, ARNOLD. Died May 14, 1917. *HALL, CHRISTOPHER W. Died May 10,1911. *HALL, JAMES. Died August 7, 1898. HATCHER, JOHN B. Died July 3, 1904. *Hay, ROBERT. Died December 14, 1895. HAYES, C. WILLARD. Died Feb. 9, 1916. *HEILPRIN, ANGELO. Died July 17, 1907. HILGARD, HuGENE W. Died Jan. 8, 1916. HILL, FRANK A. Died July 13, 1915. *HITCHCOCK, CHAS. H, Died Nov 7, 1919. *HOLBROOK, LEvr. Died July 26, 1922. *HOLMES, JOSEPH A. Died July 13, 1915. HONEYMAN, DAvID. Died October 17, 1889. *HOWELL, HDWIN H, Died April 16, 1911. *Hovey, Horace C. Died July 27, 1914. Hunt, THomAsS S. Died Feb. 12, 1892. *HyatTrT, ALPHEUS. Died Jan. 15, 1902. IppDINGS, J. P. Died Sept. 8, 1920. IRVING, JOHN D. Died July 26, 1918. JACKSON, THOMAS M. Died Feb. 3, 1912. *JAMES, JOSEPH F. Died March 29, 1897. JULIEN, ALEXIS A. Died May 7, 1919. KNIGHT, WILBUR C. Died July 28, 1903. Lacor, RaAuepH D. Died February 5, 1901. LAFLAMME, J. C. K. Died July 6, 1910. LAMBE, L. M. Died March 12, 1919. ~ LANGTON, DANIEL W. Died June 21, 1909. *LE CONTE, JOSEPH. Died July 6, 1901. *LESLEY, J. PETER. Died June 2, 1903. LOUGHRIDGE, Rost. H. Died July 1, 1917. McCALLry, Henry. Died Nov. 20, 1904. *McGrr, W J. Died September 4, 1912. Marcy, Ontvpr. Died March 19. 1899. MarsH, OTHNIEL C. Died March 18, 1899. MELL, P, H. Died October 12, 1918. *MERRILL, FRED. J.H. Died Nov. 29, 1916. MILLS, JAMES BH. Died July 25, 1901. 116 *NASoN, HENRY B. Died January 17, 1895. *NerF, Peter. Died May 11, 1903. *NEWBERRY, JOHN S. Died Dec. 7, 1892. NILES, WILLIAM H. Died Sept. 12, 1910. *ORTON, EDWARD. *OSBORN, AMOS O. Died March, 1911. *QWEN, RiIcHARD. Died March 24, 1890. PENFIELD, SAMUEL L. Died Aug. 14, 1906. PENHALLOW, Davip P. Died Oct. 20, 1910. Pirsson, L. V. Died Dec. 8, 1919. *PLATT, FRANKLIN. Died July 24, 1900. PETTEE, WILLIAM H, Died May 26, 1904. *POWELL, JOHN W. Died Sept. 23, 1902. *PROSSER, CHAS. S. Died Sept. 11, 1916. Purpun, A. HH. Died) Deer 12) 1917. RoceErs, G. S. Died Nov. 18, 1919. *RUSSELL, ISRAEL C. Died May 1, 1906. *SAFFORD, JAMES M. Died July 3, 1907. *SALISBURY, R. D. Died Aug. 15, 1922. *SCHAEFFER, CHARLES. Died Novy. 23, 1903. SEELY, H. M. Died May 4, 1917. SpNA, J. C. DA COSTA. PROCEEDINGS OF THE Died October 16, 1899. Died June 20, 1919. *SHALER, NATHANIEL S. Died Apr. 10, 1906. ANN ARBOR MEETING > *SPENCER, J. W. Died July, 1921. SAINT JOHN, O. H. Died July 17, 1921. SUTTON, WILLIAM J. Died May 9, 1915. Tarr, RALPH S. Died March 21, 1912. TIGHT, WILLIAM G. Died Jan. 15, 1910. *TopD, JAMES E. Died Oct. 29, 1922. *Van HisE, C. R. Died Nov. 19, 1918. *VOGDES, ANTHONY W. Died Feb. 8, 1923. WACHSMUTH, CHAS. Died Feb. 7, 1896. WabswortH, M, E. Died April 21, 1921. WESTON, THOMAS C. Died July 20, 1910. WHITE, THEODORE G. Died July 7, 1901. *WHITFIELD, Rost. P. Died April 6, 1910. *WILLIAMS, GEORGE H. Died July 12, 1894. *WILLIAMS, J. FRANCIS. Died Noy. 9, 1891. *WILLIAMS, H. S. Died July 31, 1918. WILMOTT, ARTHUR B. Died May 8, 1914. *WINCHELL, ALEX. Died Feb. 19, 1891. *WINCHELL, NEWTON H. Died May 1, 1914. WRIGHT, ALBERT A. Died April 2, 1905. *WRIGHT, G. F. Died April 20, 1921. YEATES, WILLIAM S. Died Feb. 19, 1908. Summary Correspondents Original Membershipte2-i50-3 ae eee Deceased Correspondents........... Heceased' Hellows:..c).%. ower eee 5) a) tel ei go falinkw ew le bidet) = © PellOWS. ci cathe, acs oe rot oe Elected. HevlowS--+ Acer l ee Dee ee ey ee rE i es 11 ee ee ee ay cee 25 ialdpaiods outs ued nda seat tce ses aed ee 452 vl owe yd (owes (ake @ Xe) ele) joa) ss ta Co Swe ete hen eee Sa, Siesta te’ os outs! atone aya eae ee aca en 123 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 117-120 MARCH 30, 1923 PROCEEDINGS OF THE TWENTY-FIRST ANNUAL MEETING | OF THE CORDILLERAN SECTION OF THE GEOLOGICAL SOCIETY OF AMERICA, HELD AT STANFORD UNIVER- SITY, CALIFORNIA, APRIL 29, 1922. Austin F. Rogers, Secretary CONTENTS Page SES STE DIE 2g Tell AN Nec efi ARR a eae ao cet eee Pee RS Our ee ee a tp lig MEU te ARO LCC TGs HOT POZO a) oN a nesc's slevs-dee Stale susie Alias Aroutolals alate’ « Wace est 118 Pate Ar MELD MOVIMTS OUTU CE tere ey cect ole nc Sit ica a isa baie, o¥s.e. sucyapebehe SiScglejcses wyerged v\o, 0.6. one 118 Miocene age of the oil shales at Elko, Nev Ane ie John P. Buwalda 118 Fauna of the Sooke formation; by B. L. Clark and Ralph Arnold. 118 Boreal marine fauna from the Upper Oligocene or Lower Miocene OL AVIBISIRGD 2 2000) B27 4d Opal OIL Gl oy agi ache i ae ee 118 Myadesma, a new genus of Pelecypoda from the marine Oligocene (OrmbNeaVesE-COmMsce Diy se Wi CLT K 17. oclclokica cancer dete caeee 118 HKocene venericardia of the west coast; by Marcus Hanna....... 118 Phylogeny of the genus Agasoma; by H. V. Howe.............. 118 Verde River lake beds near Clarkdale, Arizona; by O. P. Jenkins. 119 Erediction of earthquakes; by A. @. Lawson................02. 119 Pleistocene vertebrates from an asphalt deposit near McKittrick, Camtornia: by a. C. Merriam and’ ©. Stock.....:...........-. 119 Rock floors in arid regions; by Augustus Locke................ 119 Geological sketch of the Tsin-ling-shan, China; by R. R. Morse... 119 Morococha minine district; by M. G. Hdwards.................. 119 Geology of the Alamo mining district, Baja California, Mexico; Same erie RING EDTA) ER eee eaten rs ee Mere ua suntan eek Sere eS ee oeke Sw Oo bw cw bore oc me 119 Rossiple continental lmks: by Bailey Willis: ..:.-...s....<..... 120 puomi~enent of Nominatimg “Committee. ...... 6.26. .kk cee cee etc ec ce 120 AJLIMe UTI OIE Roig ece cin'c Bin cky DIO SDI ORO Sib) eae tn rrr 120 i eremciie Stantord meeting, 1922) 1. boc... be eke ee cece, 120 SESSION oF APRIL 29 The twenty-first annual meeting of the Cordilleran Section of the Geo- logical Society of America was held in conjunction with the Pacific Coast Branch of the Paleontological Society of America and the Le Conte Club. at Stanford University, on April 29, 1922. (117) 118 PROCEEDINGS OF THE CORDILLERAN SECTION LIST OF OFFICERS FOR 1922 President, GEoRGE D. LOUDERBACK Secretary, Austin F. Rocers Councilor, Cyrus F. ToLtMan PROGRAM OF PAPERS Vhe meeting was called to order at 10.40 a. m. by the President. After an informal talk on a skull recently found in the gravel of the San Francisquito Creek by Bailey Willis and D. B. Seymour, the follow- ing puters were presented in the order indicated: MIOCENE AGE OF THE OIL SHALES AT ELKO, NEVADA BY JOHN P. BUWALDA Paper read from manuscript and illustrated by lantern shdes. Dis- cussion by Messrs. Tolman, Lawson, Turner, and Louderback. FAUNA OF THE SOOKE FORMATION BY B. L. CLARK AND RALPH ARNOLD Presented extemporaneously by Mr. Clark. BOREAL MARINE FAUNA FROM THE UPPER OLIGOCENE OR LOWER MIOCENE OF ALASKA BY B. L. CLARK Presented extemporaneously. The last two papers were discussed by Messrs. Turner, Buwalda, Willis, Tolman, Lawson, and Howe. MYADESMA, A NEW GENUS OF PELECYPODA FROM THE MARINE OLIGOCENE OF THE WEST COAST BY B. L. CLARK Read by title. EOCENE VENERICARDIA OF THE WEST COAST BY MARCUS HANNA Presented from notes. Discussion by Messrs. Tolman, Clark, and Turner: PHYLOGENY OF THE GENUS AGASOMA BY HENRY V. HOWE Presented extemporaneously. Discussion by Messrs. Willis, Clark, and Lawson. TITLES OF PAPERS 119 The meeting adjourned for lunch, to meet at 2.15 p. m. During the noon recess a visit was made to the locality on the San Francisquito Creek, near the old Stanford residence, where the skull exhibited by Dr. Willis had been found by Mr. Seymour, a student at Stanford University. The afternoon session was called to order by the President at 2.30 p. m. VERDE RIVER LAKE BEDS NEAR CLARKDALE, ARIZONA BY OLAF P. JENKINS Read by title. PREDICTION OF EARTHQUAKES BY A. C. LAWSON J Paper read from manuscript. Discussion by Messrs. Willis, Brown, Townley, Louderback, and Tolman. PLEISTOCENE VERTEBRATES FROM AN ASPHALT DEPOSIT NEAR MOC KITTRICK, CALIFORNIA BY JOHN C. MERRIAM AND C. STOCK Paper presented by Mr. Stock. Discussion by Messrs. Tolman, Brown, Buwalda, Louderback, and Taff. ROCK FLOORS IN ARID REGIONS “BY AUGUSTUS LOCKE Read by title. GEOLOGICAL SKETCH OF THE TSIN-LING-SHAN, CHINA BY R. R. MORSE Illustrated by lantern slides. Discussion by Mr. Willis. MOROCOCHA MINING DISTRICT BY M. G. EDWARDS Presented extemporaneously as a substitute for the paper on “Chro- mite-bearing dunite from Siskiyou County, California,’ which was to have been given by Austin F. Rogers. Discussion by Messrs. Tolman and Louderback. GEOLOGY OF THE ALAMO MINING DISTRICT, BAJA CALIFORNIA, MEXICO BY C. F. TOLMAN Presented extemporaneously. Discussion by Messrs. Turner, Rogers, and Manson. 120 PROCEEDINGS OF THE CORDILLERAN SECTION POSSIBLE CONTINENTAL LINKS BY BAILEY WILLIS Presented extemporaneously. Discussion by Messrs. Turner, Brown, Louderback, and Tolman. APPOINTMENT OF NOMINATING COMMITTEE It was moved (by Willis) and seconded (by Buwalda) that the chair- man appoint a Nominating Committee to send out a ballot after the meeting. Motion carried. The following Nominating Committee was appointed: Messrs. Lawson and Tolman. The meeting adjourned at 6.15 p.m. ANNUAL DINNER The Le Conte Club dinner was held in the Stanford Union. REGISTER OF THE STANFORD MEETING, 1922 FELLOWS J. P. Buwabpa W. S. TL. Smiri B. L. Chark J. A. Tarr A. C. Lawson C: BR, Totacan G. D. Loupersack H. W, Turner A. F. Rogers B. Winuis The following visitors were in attendance: S. F. Apams R. R. Morse C. W. Brown R. N. NELSonN M. G@. Epwanrps G. Nork L. A. FausTINo Mrs. Onproyp E. L. FURLONG W. H. SHockLey S. H. GresTER J. P. SMItH M. A. Hanna C. Stock H. V. Hower ; H. D. Suruirr C. D. Hutu A. W. THomas M. C. IsRAELSKY F. G@. TicKeLu P. F. Kerr S. D. TownNLEY J. B. LEISER D. T. Trask R. P. McLavuGHLin — VORBE M. Manson —— WALTER P. P. MILLER A. V. Wooprorp BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 121-142 MARCH 30, 1923 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY PROCEEDINGS OF THE FOURTEENTH ANNUAL MEETING OF THE PALEONTOLOGICAL SOCIETY, HELD AT ANN ARBOR, MICHIGAN, DECEMBER 28-30, 1922. R. S. Bassier, Secretary CONTENTS Page nes © MEIC AY DICCAINDEr 2552555250000 coe cP lee tc we cece ee cece ses 122 nite eI CCOMIDET CO 4 oie ye ale oe Sed ep e on bel eceseercecss 123 IAM ADIIERIRCR ES 25 ott Sian. ota sidicia'c och bide alsa eo wdces sn dews 123 in Ma Mee OEE oo cei ol oe ye, os Sb bee od biddie ad eis ce bee 123 RE LEIS De NP elon 5 2 a eas a wlerotle oc o eenitjesd0scbcese 124 pettus oF Auditing Comimnitice.... 0). so et te cc ccc ec cceen 124 MMOL OMICCER ANG MCMPETS: 2.642. ec Se cde ccc ewccccccvance 124 TEE Gl cee st fore ook A Se ad ode ob bob eee 125 Election of representative on National Research Council............. 126 nn aI ak en Re ea aN Si So ae so bac bee ees vedere 126 Ou EE US Pe Oe en aS be re 126 The Burton Dictyosponge [abstract]: by John M. Clarke........ seat Restoration of the Cohoes mastodon [abstract]; by John M. EE er ae Se Ls oe baw oy lL. 127 Pyorrhca in the Cohoes mastodon [abstract]; by John M. Clarke. 127 Temple Hill mastodon [abstract]; by John M. Clarke........... iv Pliocene mammals of southern China [abstract]: by W. D. mom AMG Waner GYAHZer.. 2... obec cddvcncecs'scecccs 128 Farly Mississippian formations of the type region along Missis- sippi River in Iowa, Illinois, and Missouri [abstract]; by Ray- US pa he Sas oe Se a ee 128 Paleobotanical contributions to the stratigraphy of central Ore- Pe LAeE Eel! 7 Ie tei NY NOMANCY. 5 sooo ob ec eco oe bce. 129 es a ee ee er 130 Recent progress and trends in vertebrate paleontology: Presiden- tal address by W. D. Matthew................. nape Oa gee Rea Pe 130 New species of crested Trachodont dinosaur [abstract] : by W.A a ES a A ee a ee re 130 Some faunal correlations of the Richmond [abstract]; by W. H. NN te ae stare ee Ss SL. oe oo so oo hoe oe 130 Relations and overlaps of Ordovician formations in Kentucky and ee RRR OME OM AR BIINREN 22. socc es 25s ac. ccs ce cenenenc. 131 122 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY Page Stratigraphy of the Snake Creek fossil quarries and the correla- tion of the faunas [abstract]; by W. D. Matthew..:......:... 131 Session of..Saturday, -December 3052... 222 se sane nee ee eee g IS Embayments and overlaps in central Tennessee [abstract]; by R..S. Basslertske cocks Se ae oe erie. ee De Pe se 132 The basal Richmond of the Cincinnati Province [abstract]; by W: A. Shidelerias edd ae vies oo Se ee ee ee 132 Carnivorous Saurischia in Europe later than the Trias; by F. Vom Eiwene@s 2.0 Sie aoenee ie tater. ei atin ened eee Sy 133 Contribution to the Vomer-Parasphenoid question; by F. Von EEWOTIC 5 550 arc cig Fa Shs ore ewe eae ae 133 Lines of phyletic and biological development of the Ichthyoptery- fias byl Fs Von Bueie sc £0. bs ie «22a ees ee oe eee 133 Miocene beds about Goshen Hole, Wyoming; by F. B. Loomis. 133 Preliminary report concerning some new ostracoderms from Ohio: by J; By Carman: 2032665. 6. GaeeieleunienG oe cee eee 133 The problem of fossil multilamellar invertebrates [abstract]: b R: S: Bassler. 5. oe eee eles ae oe eee 138 American rhinoceroses and the evolution of Diceratherium; by i, S. Troxel. o.0. 2. ee hs eda see ee ee eee eee 134 Present status of the Ozarkian and Canadian systems; by E. O. Wis 560 oe sd Ae kis Se eee eee ence eas ce 134 Marine Eocene horizons of western North America; by Bruce Clark 2. cs Seed Meise Rae nia hore 3 eee 134 Sooke formation of southern Vancouver Island; by Bruce Clark and Ralph -Arnold...aios8 332 he hod oes eee eee 134 Evolution of Stropheodonta demissa (Conrad) in the Snyder Creek shale ‘of Missouri [abstract]; by E. B. Branson and games S. Williams ....0.5;. 5.0.0 .ihae wes chalet one ee 134 Register of the Ann Arbor meeting, 1922> 2... 22.45% S25s6) eee 136 Officers, Correspondents, and Members of the Paleontological Society..... 137 SESSION OF THURSDAY, DECEMBER 28 The first session of the Society, announced for 2 p. m. Thursday, De- cember 28, was postponed until Friday morning, so that the members could attend the symposium on “The Structure and History of Moun- tains and the Causes of their Development,” commencing at that time in the meeting of the Geological Society of America. The closing hour of the morning was devoted to the address of Charles Schuchert, Fellow of the Paleontological Society and retirmg President of the Geological Society of America. Professor Schuchert’s address, which was intro- ductory to the symposium, was entitled “Sites and nature of the North American geosynclines.” Thursday evening the members met with the Geological Society of REPORT OF THE. COUNCIL 423 America and other affiliated societies in the complimentary smoker ten- dered by the University of Michigan at the Michigan Union. SESSION oF Fripay, DECEMBER 29 President Matthew called the Society to order in its fourteenth annual meeting, at 9.30 a. m., in the Science Building of the University of Mich- igan. After welcoming the members, the report of the Council was read. REPORT OF THE COUNCIL To the Paleontological Society, in fourteenth annual meeting assembled: The Council has held its customary meetings just before and after the annual meeting of the Society and has transacted other business by corre- spondence. A résumé of the administration of the Society’s business during the fourteenth year is given below. SECRETARY'S REPORT To the Council of the Paleontological Society: The Secretary's report for the year ending December 27, 1922, is as follows: | Meetings.—The proceedings of the thirteenth annual meeting of the Paleontological Society, held at Amherst, Massachusetts, December 28-30, 1921, have been printed in volume 33, number 1, of the Bulletin of the Geological Society of America, pages 191-222. The Council’s proposed nominations for officers and the announcement that the fourteenth annual meeting would be held at Ann Arbor, Mich- igan, December 28-30, 1921, as the guest of the University of Michigan, was issued March 22, 1922. Membership.—The Society has been fortunate in having no loss of membership during the year. Five new members have just ‘been elected and eight additional nominations are awaiting consideration at the pres- ent meeting. This year two of our members have been elected to fellow- ship in the Geological Society of America and four Fellows of that Society have asked for election to our own. The result of these various changes leaves a total number of members at the end of 1922 of 228. Publications.—In addition to the Proceedings, four papers by members have been published in the Bulletin of the Geological Society of America. Respectfully submitted, R. S. Basser, ’ Secretary. WasHiIneton, D. C., December 26, 1922. 124 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY TREASURER’S REPORT To the Council of the Paleontological Society: The Treasurer begs to submit the following report of the finances of the Society for the fiscal year ending December 23, 1922: RECEIPTS Cash on hand’ December 24 a07I ee ao. = Sota ome oe ate $672.27 Membership. fees: 5 ok Scent eee ae Bn ee cine ores eres 297 .30 interest, Connecticut Savimes “Banke. -.c.seac eso owe emi 24.46 $994.03 EXPENDITURES Secretary’s office: Necretary’s” Allowances. fiat non eee tees $50.00 Clerical. Work YOaes se Pe Sa a ee 25.00 Office sempensesciee PW ose ee be ee eee ee 59.3 $134.30 Treasurer’s office: Treasurer's: HOWANCe sa tae sie oer oot Sey arn eee $25 .00 POSEALE HS 4.2 Se eS Eee Ne nae home 3.00 —— 28.00 Geological Society of America: Printin= “prozrams,. ClEehelac ie sisie sateravers Sie $3.45 RREPTINUS® F's SA a es See ee eee take ata aes 26.06 ———— ._ 29.51 191.81 Balance: on hand’ December 23,, 1922.23 ssc. hoe oe we ee $802.22 Net increase in “fundies se me ee es. ee oe eee $129 .95 Outstanding) dues’ (1921 Miss 1923. 1d) 7 a et ee ee 36.00 Respectfully submitted, Ricuarp 8. Lutt, Treasurer. New Haven, Connecricut, December 23, 1922. APPOINTMENT OF AUDITING COMMITTEE A committee consisting of W. H. Twenhofel and F. B. Loomis was then appointed by the President to audit the Treasurer’s accounts. ELECTION OF OFFICERS AND MEMBERS President Matthew then announced the results of the ballots for the election of officers for 1923 and of new members. ELECTION OF OFFICERS AND FELLOWS i225 OFFICERS FOR 1923 Tresident: T. WayLanp VauGHAN, Washington, D. C. First Vice-President : W. A. Parks, Toronto, Ontario Second Vice-President: W. H. Twennoret, Madison, Wis. Third Vice-President: O. P. Hay, Washington, D. C. Secretary: R. S. Basster, Washington, D. C. Treasurer: RicuarpD 8S. Lunt, New Haven Conn. Editor: : Watrer Grancer, New York City NEW MEMBERS FOR 1923 JOSIAH BripGE, Missouri School of Mines and Metallurgy, Rolla, Missouri. JENNIE Doris Dart, 114 High Street, New Haven, Connecticut. GrorceE M. En ters, University of Michigan, Ann Arbor, Michigan. HANDEL T. Martin, University of Kansas, Lawrence, Kansas. GerorGE B. TwitcHELL, 845 Dayton Street, Cincinnati, Ohio. The President then called for the following nominations to member- ship which had arrived too late for insertion on the printed ballot and which had received the approval of the Council: HENRY G. CLINTON, Superintendent of Black Mammoth Consolidated Mining Company, Manhattan, Nevada. Student of invertebrate paleontology. Proposed by E. O. Ulrich and R. S. Bassler. Epwarp J. Forres, American Museum of Natural History, New York City. Student of invertebrate paleontology. Proposed by Ralph W. Chaney and R. S. Bassler. é Hepwic T. Kniker, The Texas Company Building, Houston, Texas. M. A., University of Texas, 1917. Proposed by Julia A. Gardner and R.S. Bassler. Mrs. HELEN MORNINGSTAR LAMBORN, Department of Geology, Ohio State Uni- versity. Ph. D. (1921), Bryn Mawr. Proposed by R. S. Lull and R. S. Bassler. 126 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY JOSEPH K. Roperts, Assistant Professor of Geology; Vanderbilt University, Nashville, Tennessee. Ph. D., Johns Hopkins University, 1922. Proposed by E. W. Berry and R. S. Bassler. RicHAarRD W. SMITH, Assistant Geologist, State Geological Survey, Nashville, Tennessee. B.S., Massachusetts Institute of Technology, 1921. Proposed by E. O. Ulrich and R. S. Bassler. WALTER C. TOEPELMAN, Assistant Professor of Geology, University of Colorado, Boulder, Colorado. A. B., University of Oklahoma, 1916. Proposed by Junius Henderson and R. 8S. Bassler. PERCIVAL S. WARREN, University of Alberta, Edmonton, Alberta. B. A., Uni- versity of Toronto, 1920. Proposed by W. A. Parks and R. S. Bassler. After the qualifications for membership of each one of the above list had been presented to the Society, it was moved by Dr. Clarke and sec- onded by Professor Twenhofel that the By-Laws be suspended and that the Secretary be instructed to cast the vote of the Society for the election of these eight new nominations. Motion carried. ELECTION OF REPRESENTATIVE ON NATIONAL RESEARCH COUNCIL Dr. Matthew then announced that the election of a representative of the Society in the Division of Geology and Geography of the National Research Council was necessary, as Dr. Vaughan, having just completed three years of service in this position, was ineligible for reelection. Upon vote by the Society, after motion by Professor Twenhofel, Dr. F. H. Knowlton was elected to this position. NEW BUSINESS The Secretary announced that J. KE. Carman and John L. Tilton, both Fellows of the Geological Society of America, wished to be enrolled in the membership of the Paleontological Society, and that J. W. Gidley and Stanley Smith, just elected to fellowship in the former Society, should also be placed on our rolls. Upon motion, it was voted that the Society should add these four names to our membership. Dr. John M. Clarke moved that, in view of the surplus in the funds of the Society, the Secretary’s allowance be increased to $100. Motion carried. There being no further business, the reading of papers was commenced in general session, with President Matthew in the chair. PRESENTATION OF PAPERS The first four papers of the program, all illustrated by lantern slides, were combined into a single presentation by the author. Discussion by Messrs. Parks, Loomis, Matthew, and Troxell followed. ABSTRACTS OF PAPERS DAN THE BURTON DICTYOSPONGE BY JOHN M. CLARKE (Abstract) - This is a hexactinellid, or glass sponge, from a Chemung (Devonian) forma- tion at Ripley, Chautauqua County, New York. The specimen described is of great size; represents, it is believed, the apertural portion of the individual, and, on the basis of other known specimens, it has been restored, the restora- tion and original specimen both being in the New York State Museum. The restoration gives a length of somewhat more than 10 feet. The sponge belongs to the genus Ceratodictya and is probably identical with the species of the Chemung formation, C. carpenteriana Hall and Clarke. The original specimen was found by Mrs. H. P. Burton in her 103d year. RESTORATION OF THE COHOES MASTODON BY JOHN M. CLARKE (Abstract) The Cohoes mastodon was found in a glacial pothole in the Mohawk River at Cohoes, New York, in 1865 and its skeleton is in the New York State Mu- seum. A careful restoration of this has been made by the most careful and exact procedures and constitutes the only known attempt to represent the animal in its living state. The restoration was made by Noah T. Clarke and Charles P. Heidenrich. PYORRH@A IN THE COHOES MASTODON BY JOHN M, CLARKE (Abstract) This skeleton has pathological dentition and erupted but one tooth on the left ramus of the mandible. This tooth has an abnormal insertion and a very imperfect opposition with the upper molars. As a result, the face of the animal is deformed and an osseous lump developed on the proximal surface of the mandible. An examination of the tooth and its socket by skillful dentists seems to have demonstrated the existence of long-continued pyorrheeal condi- tions, with attendant bone necrosis. TEMPLE HILL MASTODON BY JOHN M. CLARKE (Abstract) This skeleton was exhumed in 1921 from a truck garden near Temple Hill, about four miles west of Newburgh, Orange County, New York. Except for the Warren mastodon, the skeleton of which was found not far away, the new skeleton is the most complete known, the missing bones being largely a portion of the ribs and the upper surface of the cranium, which was destroyed by the 128 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY plow of the farmer. A notable feature of the skeleton is the evident incurva- ture and overlap of the tusks at their extremities, which are beveled, one above and one below. in such a manner as to demonstrate that the tusks formed an entire circle about the trunk. Some of the results of the explorations of the American Museum of Natural History in China were presented by President Matthew in the following paper: PLIOCENE MAMMALS OF SOUTHERN CHINA BY W. D. MATTHEW AND WALTER GRANGER (Abstract) A large collection of skulls, jaws. and bones of fossil mammals was obtained by Mr. Granger in the winter of 1921-22 from a locality near Wan-hsien, in the province of Sze-chuan. The fauna is of late Pliocene or Pleistoéene age, apparently a forest facies. Principal mammals are Stegodon, a rhinoceros near R. indicus, a giant tapir, a species of gaur (Bibos), several antelopes and large and small Cervide,. a pig, a tiger, Hywna, Aeluropus, Helarctos, Cyon, Arctonyx, Viverra, a large bamboo-rat. a rabbit, a large macaque, and a new primate, probably allied to the gibbon. The following species evolved: 8S. callawayensis Swallow: Shell thick, coarsely plicate, hinge longer than greatest width of shell. S. boonensis Swal- low: Shell thick, coarsely plicate, strongly convex. S. equicostata Swallow: Shell thin, hinge shorter than greatest width of shell, finely plicate. S. cym- biformis Swallow: Shell thin, hingeline very short, finely plicate, umbo pro- jecting prominently behind hingeline. S. inflera Swallow: Shell thick, hinge- line shorter than greatest width of shell, umbo projecting prominently behind hingeline. S. navalis Swallow: Shell thick, coarsely plicate, very convex, im- perfectly developed carinate fold. The University of Missouri has more than 2,000 specimens of Snyder Creek stropheodonts and series have been arranged showing minute variations from S. demissa (Conrad) to each of the species listed above. The intermediate grades are rare, while there are large numbers of the typical forms. All of the new species disappeared before 50 feet of Snyder Creek shales had been deposited. The Society then adjourned. PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY REGISTER OF THE ANN ARBOR MEETING, 1922 Henry M. Ami K. F. MatHer Rurus M. Bagge, JR. W. D. MatrtrHew R. S. BassLER R. C. Moore J. KH. CaRMAN ApDoLF C. No£ GrorGE H. CHADWICK Wititiam A. ParxKs RatpH W. CHANEY W. I. Rogprnson JOHN M. CLARKE F. W. SARDESON 1... RL Dice T. E. SAVAGE C. O. DUNBAR CHARLES SCHUCHERT G.-M. EHLERS . W. H. SHIDELER Aveust F. FoERSTE A. O. THomas CHARLES N. GOULD J. ds. VimreN J. EK. HypDE Hie Le Trexp EK. M. KInDEE W. H. TWENHOFEL Wiis T. LEe EK. O. ULRIcH F. B. Loomis T. WAYLAND VAUGHAN Davip WHITE OFFICERS, CORRESPONDENTS, AND MEMBERS OF THE PALEONTOLOGICAL SOCIETY OFFICERS FOR 1923 President: T. W. VaueHan, Washington, D. C. First Vice-President: W. A. Parks, Toronto, Ontario Second Vice-President: W. H. Twennoret, Madison, Wis. Third Vice-President : O. Po TaAxS Washington; D.C. Secretary: R. 8S. Basster, Washington, D. C. Treasurer : RicHarpD 8S. Lurtit, New Haven, Conn. Editor: WALTER GRANGER, New York City MEMBERSHIP, 1923 CORRESPONDENTS BuckMa\, S. S., Esq., Westfield, Thame, England. DEPERET, Prof. CHARLES, University of Lyon, Lyon (Rhone), France. CANU, FERDINAND, 18 Rue du Peintre Lebrun, Versailles, France. MEMBERS ApaAms, L. A., State Teachers’ College, Greeley, Colo. ADKINS, WALTER Scott, Bureau of Economic Geology, Austin, Texas. AGUILERA, JOSE G., Instituto Geologico de Mexico, City of Mexico, Mexico. ALDRICH, TRUMAN H., 1036 Glen Iris Avenue, Birmingham, Ala. Ami, Henry M., Geological Survey of Canada, Ottawa, Canada. ANDERSON, F’. M., 2604 Etna Street, Berkeley, Calif. ANDERSON, RoBerT, 47 Parliament St., Westminster, S. W. I., London, England. ARMSTRONG, EDWIN J., 954 West Ninth Street, Erie, Pa. _ ARNOLD, RALPH, 639 South Spring Street, Los Angeles, Calif. Bace, Rurus M., Jr., Lawrence College, Appleton, Wis. BakER, CHARLES L., Rock Island Company, Cordova, III. 138 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY BaRBouR, ERWIN H., University of Nebraska, Lincoln, Nebr. Barrows, ALBERT L., 1702 Massachusetts Avenue, Washington, D. C. BartTscH, PAut, U. S. National Museum, Washington, D. C. BASSLER, Harvey, U. S. Geological Survey, Washington, D. C. BaSssLeR, Ray S., U. S. National Museum, Washington, D. C. BEEDE, JOSHUA W., 200 S. Seneca Avenue, Bartlesville, Okla. BELL, WALTER A., Geological Survey of Canada, Ottawa, Canada. BensLEY, B. A., University of Toronto, Toronto, Ontario. BERRY, EpwarpD W., Johns Hopkins University, Baltimore, Md. BipBins, ARTHUR B., 2600 Maryland Avenue, Baltimore, Md. Bostwick, THOMAS A., 43 Livingston Street, New Haven, Conn. Branson, E. B., University of Missouri, Columbia, Mo. _ Brown, Barnum, American Museum of:Natural History, New York City. Brown, THomas C., Laurel Bank Farm, Fitchburg, Mass. . BRYANT, WILLIAM L., Buffalo Society of Natural Sciences, Buffalo, N. Y. BurRLING, LANCASTER D., Whitehall Petroleum Corporation, 53 Parliament Street, Westminster, S. W., London, England. Butts, CHARLES, U. S. Geological Survey, Washington, D. C. BuWaALpA, JOHN P., Bacon Hall, University of California, Berkeley, Calif. CAMP, CHARLES L., Dept. of Geology, University of California, Berkeley, Calif. CASE, ERMINE C., University of Michigan, Ann Arbor, Mich. CHADWICK, GEORGE H., University of Rochester, Rochester, N. Y. CHANEY, RALPH W., 1232 Carlotta Street, Berkeley, Calif. CLARK, BrucE L., University of California, Berkeley, Calif. CLARK, THOMAS H., 36 Irving Street, Cambridge, Mass. CLARKE, JOHN M., Education Building, Albany, N. Y. CLELAND, HERDMAN F., Williams College, Williamstown, Mass. CLEMENTS, F.. E., Desert Laboratory, Tucson, Ariz. Cook, HAROLD J., Agate, Nebr. CooKE, C. WYTHE, U. S. Geological Survey, Washington, D. C. CorRYELL, Horace N., Dept. of Geology, Columbia University, New York City. CRANE, WILL E., 208 13th Street N. E., Washington, D. C. CuMINGS, EpGarR R., Indiana University, Bloomington, Ind. CUSHMAN, JOSEPH A., Sharon, Mass. Dat, W. H., U. S. National Museum, Washington, D. C. Darsy, FRED WILLIS, Peabody Museum, Yale University, New Haven, Conn. DEAN, BASHFORD, Columbia University, New York City. DECKER, CHARLES E., University of Oklahoma, Norman, Okla. Dick, LEE RaymMonp, Department of Zoology, University of Illinois, Urbana, III. DicKERSON, Roy E., 320 Masonic Temple, Manila, P. I. DouGLASs, EARL, Carnegie Museum, Pittsburgh, Pa. Dusots, Henry M., Box 539, La Grande, Oreg. DUNBAR, CARL O., Department of Geology, Yale University, New Haven, Conn. EATON, GEORGE F.,. 70 Sachem Street, New Haven, Conn. Evuisor, ALvA C., Humble Oil and Refining Company, 803 Humble Building, Houston, Texas. EYERMAN, JOHN, “Oakhurst,” Easton, Pa. FIELD, RicHAaRD M., Brown University, Providence, R. I. FoERSTE, AucusT F., 129 Wroe Avenue, Dayton, Ohio. LIST OF MEMBERS 139 Frick, CuiLps, 70th Street and Central Park, New York City. GALLOWAY, J. J.. Department of Geology, Columbia University, New York City. GARDNER, JULIA A., U. S. Geological Survey, Washington, D. C. GesTER, G. S., Standard Oil Building, San Francisco, Calif. GisB, HueH, Peabody Museum, Yale University, New Haven, Conn. GILBERT, J. Z., Los Angeles High School, Los Angeles, Calif. GIRAUD, ANTONIO Pastor, ¢/o Transcontinental de Petroleo, S. A., Tampico, Mexico. Guick, Perry A., 502 East Springfield Street, Champaign, I[11. GOLDRING, WINIFRED, Education Building, Albany, N. Y. GORDON, CLARENCE E., Massachusetts Agricultural College, Amherst, Mass. GouLpD, CHARLES N., 1218 Colorado Building, Oklahoma City, Okla. GRABAU, AMADEUS W., Government University of Peking, Peking, China. GRANGER, WALTER, American Museum of Natural History, New York City. GREENE, F. C., 1434 S. Cincinnati Avenue, Tulsa, Okla. Grecory, W. K., American Museum of Natural History, New York City. GRIER, NORMAN McD., Biological Laboratory, Washington and Jefferson Col- lege, Washington, Pa. , GURLEY, WILLIAM F’.. E., 6151 University Avenue, Chicago, III. HANNIBAL, HAROLD, Dept. of Geology, Stanford University, Stanford, Calif. HARRIS, GILBERT D., Cornell University, Ithaca, N. Y. HARTNAGEL, CHRIS A., Education Building, Albany, N. Y. Hay, O. P., U. S. National Museum, Washington, D. C. HAYNES, WINTHROP P., 74 Beacon Street, Hyde Park, Mass. HEATH, EUGENE SCHOFIELD, Fisk Hall, Northwestern University, Evanston, III. HENDERSON, JUNIUS, University of Colorado, Boulder, Colo. HiBBarD, RAyMonpD R., 908 Michigan Avenue, Buffalo, N. Y. HOLLAND, WILLIAM J., Carnegie Museum, Pittsburgh, Pa. Hoiiick, ArtHUR, New York Botanical Garden, New York City. Howe, Henry V., 1514 Alder Street, Eugene, Oreg. HowEI.L, B. F., Department of Geology, Princeton University, Princeton, N. J. Hvpparp, BELA, Woods Hole, Mass. Hupson, GEorGE H., 19 Broad Street, Plattsburg, N. Y. HuME, GrorceE S., Geological Survey of Canada, Ottawa, Canada. Hussakor, Louis, American Museum of Natural History, New York City. HYDE, JESSE, Western Reserve University, Cleveland, Ohio. JACKSON, RospertT T., Peterborough, N. H. JEFFREY, E. C., Harvard University, Cambridge, Mass. JENNINGS, OTTO E., Carnegie Museum, Pittsburgh, Pa. KELLOGG, REMINGTON, Bureau of Biology, U. S. Department of Agriculture, Washington, D. C. KEMPER, DoroTHy B., 2527 Benvenue Street, Berkeley, Calif. Kew, W. S. W., U. S. Geological Survey, Washington, D. C. KINDLE, EpwarpD M., Geological Survey of Canada, Ottawa, Ontario. Kirk, Epwin, U. S. Geological Survey, Washington, D. C. KnicutT, S. H., University of Wyoming, Laramie, Wyo. KNOWLTON, FRANK H., U. S. Geological Survey, Washington, D. C. LEE, WILLIS T., U. S. Geological Survey, Washington, D. C. LEONARD, H. M., Morton Street, Porterville, Calif. 140 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY TLorL, WAYNE FREDERICK, General Petroleum Corporation, Higgins Building, Los Angeles, Calif. LooMIS, FREDERICK B., Amherst College, Amherst, Mass. LULL, RIcHARD S., Yale University, New Haven, Conn. LUTHER, D. D., Naples, N. Y. MANSFIELD, WENDELL C., U. S. Geological Survey, Washington, D. C. Mark, Ciara G., Dept. of Geology, Ohio State University, Columbus, Ohio. MARTIN, Bruce, Waukena, Tulare County, Calif. MatTHer, K. F., Denison University, Granville, Ohio. MatTTrHew, W. D., American Museum of Natural History, New York City. MaATrrHew, GEoRGE F., 65 Edgar’s Lane, Hastings-on-Hudson, N. Y. MAYNARD, T. Pools, 1622 D. Hunt Building, Atlanta, Ga. McBrine, THoMAS H., University of Iowa, Iowa City, Iowa. McEwan, Evra D., Simpson College, Indianola, Iowa. McGreeor, J. H., Columbia University, New York City. McLearn, FRANK H., Geological Survey of Canada, Ottawa, Canada. MEHL, Maurice G., University of Missouri, Columbia, Mo. MERRIAM, JOHN C., Carnegie Institution, Washington, D. C. MESLER, REcTOR D., U. S. Geological Survey, Washington, D. C. MILLER, Paut C., Walker Museum, University of Chicago, Chicago, Il. Moopiz, Roy L., University of Illinois, Congress and Honore Sts., Chicago, Ill. Moopy, CLARENCE L.. University of California, Berkeley, Calif. Moox, CHARLES C©., American Museum of Natural History, New York City. Moore, R. C., University of Kansas, Lawrence, Kans. Moran, Ropert B., 215 W. 7th Street, Los Angeles, Calif. Morsk, WILLIAM C., Mississippi Agricultural and Mechanical College, Agricul- tural College, Mississippi. MoseEs, FLoRENCE HMMA, 1819 Addison Street, Berkeley, Calif. NARRAWAY, JAMES E., Department of Justice, Ottawa, Canada. NELSON, NORMAN E., 116 East 8th Street, Fort Worth, Texas. NELSON, RicHARD N., 22837 Durant Avenue, Berkeley, Calif. Nok, ApoLtr CarL, University of Chicago, Chicago, Il. NOMLAND, JORGEN O., 200 Bush Street, San Francisco, Calif. O'CONNELL, MARJorIF, American Museum of Natural History, New York City. OSBORN, HENRY FAIRFIELD, American Museum of Natural History, N. Y. City. Pack, R. W., U. S. Geological Survey, Washington, D. C. PACKARD, EARL L., Eugene, Oreg. PALMER, KATHERINE VAN WINKLE, University of Washington, Seattle, Wash. ParKS, WILLIAM A., University of Toronto, Toronto, Ontario. PATTEN, WILLIAM, Dartmouth College, Hanover, N. H. PETERSON, O. A., Carnegie Museum, Pittsburgh, Pa. PETRUNKEVITCH, ALEXANDER, 266 Livingston Street, New Haven, Conn. PRICE, WILLIAM A., JR., 1820 Great Southern Life Building, Dallas, Texas. RAYMOND, PERcy E., Museum of Comparative Zoology, Cambridge, Mass. REEDS, CHESTER A., American Museum of Natural History, New York City. REESIDE, JOHN B., JR., U. S. Geological Survey, Washington, D. C. RESSER, CHARLES E., U. S. National Museum, Washington, D. C. Ricuarps, EstHer E., Rio Bravo Oil Company, Southern Pacific Building, Houston, Texas. LIST OF MEMBERS 4) Riees, BH. S., Field Museum of Natural History, Chicago, Ill. Ropinson, WixBuR I., Geological Survey of Michigan, Lansing, Mich. Romer, A. S., 422 W. 20th Street, New York City. Rounpy, Pauvt V., U. S. Geological Survey, Washington, D. C. Row ey, Rospert R., Louisiana, Mo. RUEDEMANN, RupoLtr, Education Building, Albany, N. Y. RUSSELL, RicHARD JOEL, 2412 Piedmont Avenue, Berkeley, Calif. SARDESON, FREDERICK W., 414 Harvard Street, Minneapolis, Minn. SARLE, CLIFTON J., University of Arizona, Tucson, Ariz. SAvAGE, THOMAS E., University of Illinois, Urbana, Ill. ScHUCHERT, CHARLES, Yale University, New Haven, Conn. Scort, WILLIAM B., Princeton University, Princeton, N. J. SELLARDS, Ertas H., University of Texas, Austin, Texas. SHIDELER, WILLIAM H., Miami University, Oxford, Ohio. SHIMER, HERVEY W., Massachusetts Institute of Technology, Boston, Mass. SINCLAIR, WILLIAM J., Princeton University, Princeton, N. J. Stocom, ARTHUR WARE, Walker Museum, University of Chicago, Chicago, Ill. SMITH, BuRNETT, Syracuse University, Syracuse, N. Y. SPRINGER, FRANK, U. S. National Museum, Washington, D. C. Stanton, T. W., U. S. Geological Survey, Washington, D. C. STAUFFER, CLINTON R., University of Minnesota, Minneapolis, Minn. STEPHENSON, L. W., U. S. Geological Survey, Washington, D. C. STERNBERG, CHARLES H., Lawrence, Kans. Stock, CHESTER, 2839 Forest Avenue, Berkeley, Calif. STONER, REGINALD C., Standard Oil Building, San Francisco, Calif. STRICKLAND, FRANK PrteER, JR., 640 Oakland Street, Kansas City, Mo. Swartz, CHARLES K., Johns Hopkins University, Baltimore, Md. TaLgBoT, Mignon, Mt. Holyoke College, South Hadley, Mass. TELLER, Hpcar E., 66 Highland Street, Buffalo, N. Y. THomas, A. O., University of Iowa, Iowa City, Iowa. THOMPSON, ALBERT, American Museum of Natural History, New York City. THORPE, Matcotm R., Osborn Zoological Laboratory, Yale University, New Haven, Conn. TiEJE, ARTHUR J., Dept. of Geology, University of Colorado, Boulder, Colo. TRASK, PARKER Davies, 1502 Alice Street, Oakland, Calif. TROXELL, Epwarpd L., Osborn Zoological Laboratory, Yale University, New Haven, Conn. TWENHOFEL, WILLIAM H., University of Wisconsin, Madison, Wis. TWITCHELL, M. W., Geological Survey of New Jersey, Trenton, N. J. ULRICH, Epwarp O., U. S. Geological Survey, Washington, D. C. UNGER, CLAUDE E., Pottsville, Pa. Van DELoo, JAcos, Education Building, Albany, N. Y. VAN INGEN, GILBERT, Princeton University, Princeton, N. J. VAN TuyL, Francis M., Colorado School of Mines, Golden, Colo. VAUGHAN, T. WAYLAND, U. S. Geological Survey, Washington, D. C. VoGpES, ANTHONY W., 2425 First Street, San Diego, Calif. WAGNER, CARROLL MARSHALL, 2520 Wilshire Building, Los Angeles, Calif. WALcorT, CHARLES D., Smithsonian Institution, Washington, D. C. WALTER, OTTto F., 421 Reynolds Street, Iowa City, Iowa. | 142 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY WEAVER, CHARLES F., University of Washington, Seattle, Wash. WELLER, STUART, University of Chicago, Chicago, III. WHITE, Davin, U. S. Geological Survey, Washington, D. C. WHITTAKER, EDWARD J., Geological Survey of Canada, Ottawa, Canada. WIELAND, G. R., Yale University, New Haven, Conn. WILLIAMS, MERTON Y., University of British Columbia, Vancouver, B. C. WILson, ALIcE E., Victoria Memorial Museum, Ottawa, Canada. WixLson, Herrick E., 224 West College Street, Oberlin, Ohio. Winton, W. M., Texas Christian University, Fort Worth, Texas. WoopRING, WENDELL P., U. S. Geological Survey, Washington, D. C. WooprorD, ALFRED OSWALD, Pomona College, Claremont, Calif. NEW MEMBERS JOSIAH BripGE, Missouri School of Mines and Metallurgy, Rolla, Mo. J. E. CARMAN, Ohio State University, Columbus, Ohio. Henry G. Crinton, Black Mammoth Consolidated Mining Company, Manhat- tan, Nev. JENNIE Doris Dart, 114 High Street, New Haven, Conn. GEORGE M. EHLERS, University of Michigan, Ann Arbor, Mich. Epwarp J. Fortes, American Museum of Natural History, New York City. J. W. GipLtey, U. 8S. National Museum, Washington, D. C. Hepwie T. KnrKer, The Texas Company Building, Houston, Texas. HELEN MorRNINGSTAR LAMBORN, Ohio State University, Columbus, Ohio. Hanpvevt T. Martin, University of Kansas, Lawrence, Kans. JosEPH K. Roperts, Vanderbilt University, Nashville, Tenn. RicHarp W. SMITH, State Geological Survey, Nashville, Tenn. STANLEY SMITH, Queens University, Kingston, Ontario. J. L. Titton, Morgantown, W. Va. WaLterR C. TOEPELMAN, University of Colorado, Boulder, Colo. GEORGE B. TwITcHELL, 845 Dayton Street, Cincinnati, Ohio. PercivaAL S. WARREN, University of Alberta, Edmonton, Alberta. CORRESPONDENTS DECEASED KoKkEN, E. Died Nov. 24, 1912. WoopwarbD, Dr. H. Died Sept. 6, 1921. Natuorst,.Dr. A. C. Died Jan. 20, 1921. MEMBERS DECEASED BARRELL, JOSEPH. Died May 4, 1919. DAMLIN, HOMER. Died in July, 1920. BiLuines, W. R. Died March 1, 1920. Harper, GEORGE W. Died Aug, 19, 1918. CALVIN, SAMUEL. Died April 17, 1911. Hawver, J.C. Died May 15, 1914. CLarK, WM. B. Died July 27, 1917. LAMBE, L. M. Died March 12, 1919. CrozEL, GEORGES. Died Oct., 1921. Lyon, Victor W. Died Aug. 17, 1919. DERBY, ORVILLE A, Died Nov. 27, 1915. Moopy, W. L. Died Oct. 9, 1920. DongeGHY, JoHN T. Died June 29, 1921. PROSSER, C. 8. Died Sept. 11, 1916. EASTMAN, CHAS. R. Died Sept. 27, 1918. SEELY, HENRY M. Died May 4, 1917. FONTAINE, WM. M, Died April 30, 1913. WARING, CLARENCE A, Died Nov. 4, 1918. GILL, THEODORE N. Died Sept. 25, 1914. WILLIAMS, Henry S, Died July 31, 1918. Gcorpon, Ropert H. Died May 10, 1910. WILLISTON, S. W. Died Aug. 30, 1918. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 143-146 MARCH 30, 1923 PROCEEDINGS OF THE SECOND ANNUAL MEETING OF THE SOCIETY OF ECONOMIC GEOLOGISTS, HELD AT ANN ARBOR, MICHIGAN, DECEMBER 28-30, 1922. Sypney H. Batu, Secretary CONTENTS Page Pemnmetehapnrsiay. Mecember 28... 4.02 oo. donk ok cect beck c code cadelgaes 143 Pa eee ay. WEECEMDECE, 20). 2a). 6 cals, Sale de dice cds ok ce wb Sera ules e eae 145 PR eaae OM VOMICOES fOTs DOD os) kia bc alge 8 al Uarsted ots Bele Sebo we de 143 PES ED BUCO IE” | O21) OLE SY Sheree aan ca ae ca ace AC 145 Po Mnimorasaitiraay, December 30... 060 .. 0o. ls cca ced da ese e ce eccee 145 Pee ee MOM Ole HDAPDEIS 2 pe) oper cals sas pers a2ccu Os lyig wale Bd we VOIR Shee ok ae 145 SESSION oF THURSDAY, DECEMBER 28 The second annual meeting of the Society of Economic Geologists was held at Ann Arbor, Michigan, December 28-30, 1922, simultaneously with the meetings of the Geological Society of America. : SESSION OF Fripay, DecEMBER 29 The session of Friday was called to order by President Waldemar Lindgren. ELECTION OF OFFICERS FOR 1923 The election of officers for 1923 was declared to have resulted as follows: President, J. E. Spurr Vice-President, ANDREW C. Lawson Councilors, 1923-1924, Ratpu Arnoxp, L. C. GRATON, and WILLET G. MILLER PRESENTATION OF PAPERS The following papers were presented during the meeting: (143) 144 PROCEEDINGS OF THE SOCIETY OF ECONOMIC GEOLOGISTS 1. THE HOMESTAKE OREBODY BY SIDNEY PAIGE Discussed by Messrs. Spurr, Runner, Lindgren, and U. 8. Grant. 2. CRITERIA BY WHICH TO DETERMINE THE DIRECTION OF FAULTS BY BAILEY WILLIS Discussed by Messrs. Spurr, Paige, Hotchkiss, Lindgren, and Kemp. 3. STRUCTURAL FEATURES EXHIBITED BY THE QUARTZITES IN THE LEAD REGION, SOUTH DAKOTA BY J. J. RUNNER Discussed by Messrs. Spurr, Paige, Lindgren, and U. 8. Grant. 4. GEOGRAPHIC DISTRIBUTION OF ORE DEPOSITS IN AUSTRALIA BY E. C. ANDREWS Read by title. 5. CONCENTRATION AND CIRCULATION OF THE ELEMENTS FROM THE STANDPOINT OF ECONOMIC GEOLOGY PRESIDENTIAL ADDRESS BY WALDEMAR LINDGREN 6. NATIVE COPPER DEPOSITS OF MICHIGAN? BY L., C2 (GRATON Discussed by Messrs. Graton, Kemp, Seaman, Leith, Lane (read ex- tract of his report, read extract of Jaggar, and spoke), Lawson, Leith, Grout, Leith, Bateman, Lewis, Butler (in rebuttal), Wells, Hotchkiss, Bayley, Butler, Wright, Bayley, Wright, Lane, and Graton. 7. SOLVENTS AND PRECIPITANTS OF METALLIC COPPER BY ALFRED C. LANE? Discussions same as number 6. 8S. CHEMICAL SUGGESTIONS CONCERNING THE ORIGIN OF LAKE SUPERIOR COPPER ORES BY R. C. WELLS? Discussions same as number 6. 1 Presented by courtesy of Geological Department, Calumet and Hecla Mining Company. 2Introduced by B. S. Butler. 3 Introduced by B. S. Butler. TITLES OF PAPERS 145 9. SOME CONSIDERATIONS RELATING TO THE ORIGIN AND HISTORY OF THE LAKE SUPERIOR SYNCLINE BY W. O. HOTCHKISS . Discussions same as number 6. 10. MAGNETIC SURVEYING ON THE COPPER-BEARING ROCKS OF WISCONSIN BY HENRY R. ALDRICH + Discussions same as number 6. 11. NATIVE COPPER DEPOSITS OF THE SOUTHERN ATLANTIC STATES AS COMPARED ESPECIALLY WITH THOSE OF MICHIGAN BY THOMAS L. WATSON. Read by title. 12. GENETIC COMPARISON OF THE MICHIGAN AND BOLIVIAN COPPER DEPOSITS BY JOSEPH T. SINGEWALD, JR. Read by E. B. Mathews. 13. SIMILARITIES AND CONTRASTS BETWEEN NATIVE COPPER DEPOSITS OF NEW JERSEY AND OF MICHIGAN BY J. VOLNEY LEWIS Discussions same as number 6. SESSION OF SATURDAY, DECEMBER 30 PRESENTATION OF PAPERS 14. MOTHER PLANTS OF PETROLEUM BY DAVID WHITE 15. CORRELATION OF OIL-BEARING ROCKS IN COLORADO AND WYOMING BY WILLIS T. LEE 16. CAPILLARY RELATIONS OF OIL AND WATER BY (C. W. COOK Discussed by O. E. Meinzer. * Introduced by W. O. Hotchkiss. X—BuULL. Grou. Soc. AM., VoL. 34, 1922 146 TITLES OF PAPERS 17. RGAD MATERIALS INVESTIGATION IN WISCONSIN BY E. F. BEAN Discussed by W. A. Nelson. 18. SUGGESTED EXPLANATION OF THE HIGH FERRIC [RON CONTENT OF LIMESTONE CONTACT ZONES BY B. S. BUTLER 19. AN EFFECT OF CLIMATIC CHANGE ON THE SUPERFICIAL ALTERATION OF ORE DEPOSITS BY HENRY H.. KNOX Read by title. 20. TITANIFEROUS IRON ORES OF WESTERN NORTH CAROLINA BY W. S. BAYLEY Discussed by H. S. Washington. 21. PRIMARY CHALCOCITE, BRISTOL COPPER MINE, CONNECTICUT’ BY ALAN M. BATEMAN Discussed by Messrs. Lewis and Graton. 22. A SOURCE OF PRESSURE FOR ORE FORMATION BY L. C. GRATON Discussed by Messrs. Lawson, Bowen, Wright, Larsen, and Spurr. 23. MAGNETITE PEGMATITES IN NORTHERN MINNESOTA BY FRANK F. GROUT Discussed by Messrs. Miller, Wright, Lane, and Lawson. 24, LADDER VEINS IN MINNESOTA BY FRANK F. GROUT Discussed by Messrs. Miller, Wright, Lane, and Lawson. 25. ROCK ALTERATION IN CONTACT WITH SULPHIDES AT SUDBURY, ONTARIO BY ALFRED WANDKE AND ROBERT HOFFMAN ” 5 Introduced by L. C. Graton. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 147-150 MARCH 30, 1923 PROCEEDINGS OF THE THIRD ANNUAL MEETING OF THE MINERALOGICAL SOCIETY OF AMERICA, HELD AT ANN ARBOR, MICHIGAN, DECEMBER 29, 1922. Frank R. Van Horn, Secretary pro tempore CONTENTS Page Session of Friday, December 29...........2-- esse eres ec ceecees bette eees 147 Miection of ofiicers and Fellows for 1928.....-.....00.066- cece ceen 147 Penri OF the Secretary... fic. see se cee nie else st eee eee meee eens 148 Srtmeminitie PrCASUNEl. . 02. coe eed. oe eth a et cece er seer eres ee 148 Eerie beihie TOGIEOR =. oe ea be ce ee ks ea ties eieie ge wise ce elem nlt cee pele aes 148 Report of the Committee on the Nomenclature and Classification of 0 UPL EIDE Y StL og Pet Mes esa 0 a oer ee ee ee 149 Greetings to Professors Groth and Goldschmidt...... SS a Ee 149 EPLSiLG@ Tin iE Og ee 6 SOS MIE eee nen ae ie ee ares eee 149 SESSION OF FripAy, DECEMBER 29 The Mineralogical Society of America held its third annual meeting at the University of Michigan, Ann Arbor, Michigan, on December 29, 1922, in affiliation with the Geological Society of America. The meeting in the Mineralogical Lecture Room was called to order at 9.30 a. m. by President Thomas L. Walker. In the absence of the retiring Secretary, Herbert P. Whitlock, it was moved, seconded, and carried that Frank R. Van Horn act as Secretary pro tempore. On motion of the Secretary, the reading of the minutes of the last annual meeting was dispensed with, in view of the fact that they have been printed on pages 45-50 of volume 7, number 3, of the American Mineralogist. ELECTION OF OFFICERS AND FELLOWS FOR 1923 The Secretary announced that 64 ballots had been cast for the officers for 1923, as nominated by the Council, and that the list was elected. It is as follows: (147) 148 PROCEEDINGS OF THE MINERALOGICAL SOCIETY President, Epaar T. WHERRY Bureau of Chemistry, Washington, D. C. Vice-President, GEoRGE F. Kunz New York City Secretary, FRaNK R. Van Horn Case School of Apphed Science, Cleveland, Ohio . Treasurer, ALBERT B. PEcK : University of Michigan, Ann Arbor, Mich. Editor, Watter F. Hunt University of Michigan, Ann Arbor, Mich. Councilor, Esper S. LARSEN U. 8S. Geological Survey, Washington, D. C. The Secretary also reported that the Council had elected the following Fellows: ALFRED ScHOEP, Professor of Crystallography and Mineralogy. University of Ghent, Belgium. W. L. Ucetow, Professor of Mineralogy and Petrology, University of British Columbia, Vancouver, B. C. FRANK A. WILDER, North Holston, Virginia. WASHINGTON A. ROEBLING, Trenton, New Jersey. Epwarp F. HoLtpen, University of Michigan, Ann Arbor, Mich. REPORT OF THE SECRETARY The Secretary reported that the roll of the Society now comprises 69 Fellows and 167 members, a gain of 3 Fellows and 12 members for the year. REPORT OF THE TREASURER The Treasurer read his report for the year. On motion, an Auditing Committee, consisting of Dr. KE. T. Wherry and Prof. A. L. Parsons, was appointed by the President. This committee, at a later session, reported that they found the books of the Treasurer correct. REPORT OF THE EDITOR The Editor reported an increase in the size of the American Mineral- ogist of 21.5 per cent for the year 1922. Of the 214 pages comprising TITLES OF PAPERS 149 volume 7, 59.1 per cent of the space was devoted to original articles, 22.5 per cent to proceedings of societies, notes and news, and book reviews, leaving 18.3 per cent for new minerals and abstracts. REPORT OF THE COMMITTEE ON THE NOMENCLATURE AND CLASSIFICATION OF MINERALS Prof. Thomas L. Watson, chairman of the committee, read a lengthy report. It was moved to issue the latter part of this report to the mem- bers of the Society for criticism and comment. It was moved by Prof. E. H. Kraus, also seconded .and carried, that the Society extend a vote of thanks to the committee for its efforts during the past two years. GREETINGS TO PROFESSORS GROTH AND GOLDSCHMIDT It was moved, seconded, and carried that the greetings of the Society be extended to Professors Paul Groth and Victor Goldschmidt on the approaching anniversaries of their 80th and 70th birthdays. PRESENTATION OF PAPERS The presentation of scientific papers was then taken up as follows, according to the program: PROGRESS OF MINERALOGICAL METHODS PRESIDENTIAL ADDRESS BY THOMAS L. WALKER POSSIBLE SOURCE OF METALLIC SULPHIDES IN LIMESTONE BY ALEXANDER H. PHILLIPS MINERALOGRAPHY AS AN AID TO MILLING BY ELLIS THOMSON Read by A. L. Parsons. FORMATION OF KAOLIN AT MODERATE DEPTHS BY A. L. PARSONS HISINGERITE FROM DELAWARE BY ALFRED C. HAWKINS CATAPELHUTE FROM MAGNET COVE BY W. F. FOSHAG Read by E. T. Wherry. 150 PROCEEDINGS OF THE MINERALOGICAL SOCIETY. COMPOSITION OF THOMSONITE BY EDGAR T. WHERRY VOLUME ISOMORPHISM IN THE SILICATES BY EDGAR T. WHERRY URANITE GROUP: AUTUNITE, CARNOTITE, SINCOSITE, ETCETERA BY W. T. SCH ALER Read by Frank R. Van Horn. USE OF PROJECTION APPARATUS IN TEACHING CERTAIN PHASES OF MINERALOGY BY EDWARD H. KRAUS OCCURRENCE OF LEUCITE IN THE ALBAN HILIS BY HENRY S. WASHINGTON CRYSTALLOGRAPHY AND OPTICAL PROPERTIES OF A URANIUM MINERAL (SCHOEPITE), FROM THE CONGO BY T. L: WALKER ELLSWORTHITE, NEW HYDROUS URANIUM COLUMBATE FROM HYBLA, HASTINGS COUNTY, ONTARIO BY T. L. WALKER AND A. L. PARSONS VANADIUM DEPOSITS OF THE SOUTHWEST AFRICAN PROTECTORATE BY CHARLES PALACHE DIAMOND MINES OF SOUTH AFRICA BY CHARLES PALACHE en AL SOCIETY oF AMERICA tee a *4 . - i ma 2 mm = oe OFFICERS, 1923 a Bee = President: 3 | 3 e | o Davin WHITE, Washington, D. C. : . ae Vice-Prestdents: ; : ae WILLIAM H. Hoszss, Ann Arbor, Mich. | . - Bete yy Wiit1am H. Emmons, Minneapolis, Minn. —. at, T. WayLAND VAauGHAN, Washington, D. C. BS = : -Epear T. WHerry, Washington, D. C. = a . 3 Secretary: ad * ag AtrreD H. Brooxs, Washington, D. C. Ae Y aes ¥ | it oe 7 é. ae i Sa f s logical Society of America . x z = ~~ “ rs it ites ~ a P « — a f ~ J > ae yeas *VYorumr 34 Numer 2. | ! e ee JUNE, 1923 PUBLISHED BY THE SOCIETY Sites. ahd. Nature eon Shee Maat American Gederucines ye Presidential Address by Charles Schuchert < pee 51-230 bi Kober's ‘hear of Orogeny. By Chester R. Longwell ce ee 231-242 Gi The Asiatic Arcs. By William Herbert Hobbs - - - - 243.252. Cross-section of the Appalachians in Southern New England. he 2 By J.B. Woodworth - - - - - - - - - = = = 253.262 : Structure of the Rocky Mountains in Idaho and Monta. ie Bran By George Rogers Mansfield - - - - - - - - | 263-284 — Building of the Southern Rocky. Mountains. Y Willis T. > (33a Lee a - ain aioe 285-308 | a With Notes on Isostasy. By C. E. oe ie and | Elastic Yielding of the Earth’s Crust Under a Load of Sedimentary Deposits. By Walter D. Lambert. Outlines of Appalachian Structure. By Arthur Keith} = : 309-380 | Contribution to the Hypothesis of Mountain Formation. se ae By E. C. Andrews» =" =) =o gate 2 Si he ae 381-400 a BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Subscription, $10 per year; with discount of 10 per cent to institutions and ~~ : libraries and to individuals residing elsewhere than in North America. Post- age to foreign countries in the postal union, forty (40) cents extra. Communications should be addressed to The Geological Society of America, 7ith Street and Central Park, West, New York City, or care of Florida Avenue a and Eckington Place, Washington, D. C. ar NOTICE.—In accordance with the rules established by Council, claims for non-receipt of the preceding part of the Bulletin must be sent to the Secretary of the Society within three months of the date of the receipt of this number in order to be filled gratis. a Entered as second-class matter in the Post-Office at Washington, D. C., under the Act of Congress of July 16, 1894. ( Acceptance for mailing at special rate of postage provided for in Section 1103, ~ Act of October 3, 1917, authorized on July 8, 1918. PRESS OF JUDD & DETWEILER, INC., WASHINGTON, D. C. ASG lS ee BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 151-230 JUNE 30, 1923 SITES AND NATURE OF THE NORTH AMERICAN GEOSYNCLINES ? PRESIDENTIAL ADDRESS BY CHARLES SCHUCHERT (Read in part before the Society December 28, 1922) CONTENTS Page PDI EV EEINOES 5 bed gE GIR en es ee 152 PiceeOmpme DNCOrY Of SCOSVNEMINEG. We oi. icy oe et ee nae ee oe ve een cweceees 153 ELL ETOAC SM CTIRISIUOT TREN IEE: SiR Giles 52 DA ite le a it a nea a re ee ee 153 Hall’s theory of synclines and crustal folding.............. LORIN a 155 Dana on geosynelines, synclinoria, and anticlinoria.................- 156 Twopands of geosynclines in North America...........56..c20ece en 157 PM CILNSROl NOLEN cAIMECTIGA 2 asc s res ces ec see soe ws ee ewe ety a glee wees 158 VEEP S: CH ISICTTISSTVOIOTS, oS el oa a Oa Se Rn or IN tro gg gh 158 lo UTES CULES) 2 sy edo Stee oie SI es Sa os ne en ee 160 Pare TENCE ONCISCOULCA. sicise se clei wale Ree ts sia sok Sale baees selec e ae eee os 162 eer ae tee NN Teche ee le aia a ohep a ells) MU wastes © Svs Gate mi 6 08 163 Memamonnuctesr area of North America. ......054 62.25. ee ce ees 164 PS ETPELSEM, -CHISCUISSUIOTE as, 0 arora At sen ea a 164 aaa SNES PEERS Feat Sea Re es oho Tea cas iay ated bel oidlalce @) alel aes «i ww a Quace ee ebee 165 (2 ee Sm es 5 on 2 SSSR ey a nr ee 166 Po la Sy TIGNES 5 LR Re Tes eis cP a 166 eae EN AMM ese TIME MNT ae wn laleyerclsl 6 s.s\ovas 4s wore «clea dl wits come se ae eine sac 166 Nem GUnS Wick SeCANtICHME .. 0. ee eee ee oaks SAR Sep neat a a ate gis 166 CSTE CIE SSS TEN GUI NOS ae NARS AS ears See ecient ar o 167 SEE eZ EO CI GUIS iie ae) 5 © eo eoteis sin + oie ie arile eternieiefves sia eee wk ed eee we es 168 Development of the Appalachian geosyncline......... Ben ite pea 3 5 170 SEO SC MINE Spat SCUBA ors) cus'e =e aie yie, = dhe adie sole ¥ wre atehere MMS Aioie wyiei's Salle 8 wes 170 SMES TE AVES) oy OOS IS BSS Sh er aS ee moyevee clotak Aenea AVA veniaimn, SCOSVNEMME?. ...i. cc eee See wa ea eens Ae Pe snMlcred Appalachian /SCOSVNCINE Oi. L228 lls cele ec bee wee ee ees at2, Sea AWIONCC LCOS MICHIE. 5 2..cicc civ aise s see velco sew ewld eve ecena neces ACC Memcronment Oo: the Acadian geosyncline... ........ 6. cece ee ce eee eee 179 eae armas TE Se OT TON TN) ooe ene eh ee osc cle cnc Sle aleiclew Mla neds sac se eee ees 179 emrpanar AIAN eG eye de Pei wrote Gls Cle a ieg Sw ee be siete bcc cs secs ce cs cee 180 Percmpment, of the Ouaenita embayment... 0... ee cee 181 1 Manuscript received by the Secretary of the Society April 19, 1923. This paper is one of a series composing a “Symposium on the structure and history of mountains and the causes of their development.” XI— Bout. Grou. Soc. AM., Vou. 34, 1922 (151) 152 Cc. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES Page Development of the Cordilieran s2éo0syneline=..... 25. 00ce see ele eee 184 General ‘developments 3.2565 Sa soe alk oe sshd Se ee 184 Barly Cordilleran: seosyneline..)...3.+ eee eee ns hatwide ake aut ates ee 185 Rise of the Ancestral Rocky ‘Mountains geanticline................. 186 Late. Cordilleran;> se0synclineé,-. #3 5. ea, oo eek on hee eee 187 Rise of the Cordilleran Intermontane geanticline................... 187 Pacific sequent. Séosyneline. . 9... «a... eee Seo eee 188 Rocky, Mountain sequent geosyneline. -...... set.o0s. cece es eee 189 Sonoran embayMenhs osc. 6.6.4 Geers ee ew sa cia eee ee 192 Development of the Franklinian geosyneline:- 7.5. 2.2 ....-+ 4 oe 192 Nature of mediterraneans compared with geosynclines...-............... 194 General GiSEUSSLON GD Le escians sdk 5 ER le Shenae te etnias eos beds ae en 194 MonogzeosyHClines.. 2 orcas sg oi ei aie tee oo See halts Stee eens > te en 195 PolYSCOSYNGELINES so: 55.5 alates) is Ss sha weg weve Oe he wees nok oe 196 Mesogeosynclines, or mediterraneans............... aoe 0 sno in abs IT OGGATIS Joseph Le Conte: Earth-crust movements and their causes. This Bulletin, vol. 8, pp. 113-114. INTRODUCTION 153 almost universal law there is but one exception, namely, the internal forces of the earth. “Thus, then, all geological agencies are primarily divided into two groups. In the one group come atmospheric, aqueous, and organic agencies, together with all other terrestrial phenomena which constitute the material of science; in the other group, igneous agencies and their phenomena alone. The forces in the one group are exterior; in the other, interior; in the one sun-derived ; in the other, earth-derived. The one forms, the other sculptures, the earth’s features. . . . The general effect of the one is to increase the inequalities of the earth’s surface, the other to decrease and finally to destroy them. All that constitutes physical geography at any geological time is determined by the state of balance between these two eternally antagonistic forces.” It is now well established that the geologic history of the earth is cyclic in its nature, cyclic in that the periods have (1) long intermediate times when the lithosphere undergoes peneplanation and warping move- ments comprehended under the term epeirogenic, and (2) shorter closing epochs when the earth’s outer shell is locally folded into mountains, the orogenic times.. During the intermediate times, organic evolution is al- most static (biostatic), but is quickened in the cooler and drier orogenic epochs. The times of lesser crustal folding occur toward the close of the periods, and when the diastrophism is world-wide, as toward the close of the eras, then the, life of the earth passes through critical or revolutionary times, with quickened evolution and vanishing of the overspecialized stocks. The cause of the cyclic changes in the surface of the earth is to be sought in the variable tensions in, and the elasticity of, the lthosphere. These are brought about by radial shrinkage, or the contraction energies. ‘The tensions are of slow accumulation during the epeirogenic times, and they give way to crustal movements during the orogenic epochs of com- pensation. RIsE OF THE THEORY OF GEOSYNCLINES GENERAL DISCUSSION The unraveling of American geology began in earnest with the or- ganization of the State Survey of Massachusetts in 1830, and in 1836 that of New York, the State destined to be the court of last resort in Paleozoic stratigraphy. Merrill tells us in his comprehensive “Contri- butions to the history of American geology” that during the decade 1830- 1839 official surveys were organized by no fewer than fifteen States, and national ones carried on by Owen and Featherstonhaugh in the Missis- sippi Valley. During the next twenty years eleven other State surveys 154 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES came into being, besides the path-finding Federal ones of Foster and Whitney in the Lake Superior country, and the railway surveys across the Rocky Mountains of Emory, Marcy, Pope, Ives, Newberry, and Macombe. The stratigraphic results of these many and widely spread ‘geologic and geographic efforts stand recorded chiefly in the work of Hall, Vanuxem, and Emmons in New York and elsewhere, of Hitchcock in New England, of the brothers Rogers in Pennsylvania and Virginia, of Safford in Tennessee, of Owen in the Mississippi Valley, and of Daw- son and Logan in Canada. In the matter of mountain origins, the path was blazed first by the Rogers brothers and later by James Hall, followed by James D. Dana and Joseph Le Conte. The area of their generalizations was chiefly the Appalachian Mountains, extending from Tennessee through the Vir- ginias, Pennsylvania, New York, Vermont; thence northeast through Quebec to Gaspé. As early as 1842 the Rogers brothers offered an ex- planation, not only for the structure of the Appalachians, but for their causes as well, though H. D. Rogers did not see his epochal “Final Reports on Pennsylvania” published until 1858. The pioneer theory of mountain-making which is of most interest to us at present, however, was that of James Hall, first formulated in his presidential address on the “Geological history of the North American Continent,” before the American Association, at Montreal, in 1857—ac- cording to J. M. Clarke, Hall’s “most notable performance in philosoph- ical geology,” having “‘all the exciting interest of novelty.” This address had to do with the procedure of mountain-making and continental uplift. “Tt was a carefully thought out course of argument,” continues Clarke ; “but obviously Hall presented it with tentative caution and some degree of timidity—at all events, with entire absence of finality—for he would not permit its publication in the usual way in the next year’s volume of the Association’s proceedings.” ® In the meantime Hall hinted at his ideas in the “Geology of Iowa” (1859), and set them forth more in detail in the third volume of the “Paleontology of New York,” published in 1861. Even after reading this more extended account, however, one gets no such clear mental pic- ture of Hall’s theory as in the original statement of 1857, first published in 1883.* Hall’s views are not yet altogether clear, and it is therefore no wonder that “the geologists went away from Montreal shaking their heads,” and that shortly afterward Hall was told by Dana that he had *J. M. Clarke: James Hall, of Albany, geologist and paleontologist, 1921, p. 325. *James Hall: Contributions to the geological history of the American continent. Proc. Amer. Assoc. Ady. Sci., vol. 31, pp. 29-69. RISE OF THE THEORY OF GEOSYNCLINES 155 developed “a theory of mountains with the origin of mountains left out.” To this Le Conte added that Hall left “the sediments just after the whole preparation had been made, but before the actual mountain formation has taken place.” ° - Hall’s ideas of mountain origin, as we see his theory now, refer rather to mountains of sculpture, since he held that their internal structure was impressed upon them during the time of their sedimentary accumulation. “Tt is certainly one of the great glories of American geology to have clearly shown by the study of the Appalachian chain the immensity of the work of erosion, and that the present sculpture owes its origin to this cause alone.” ® HALL’S THEORY OF SYNCLINES AND CRUSTAL FOLDING Putting together all of Hall’s various statements, his theory as to the making of the Appalachian Mountains is briefly as follows: Mountains occur only in areas of greatest sedimentary accumulation, and never where formations are thin. Where the strata are thickest, there they accumulated in shallow seas, and the whole subsiding area, whether the sinking was gradual or periodic, always remained shallow. A northeastern ocean, spreading southwestward into Canada and the United States, gathered the detritals of Laurentia, and more especially of Appalachia, and laid them down along the northwestern side of the latter land, where the currents were strongest. This interior ocean, as he called it, extended westward to the Rocky Mountains. In the Appa- lachian seaway, he said, the Paleozoic formations are possibly ten times, and certainly six times, thicker than the equivalent deposits of the same seas In the Mississippi Valley. In consequence the area of greatest sedi- mentary accumulation formed a very long and comparatively narrow mass of stratified rock having eventually the general structure of a vast and very deep syncline that lay closely adjacent to an eastern land which rose periodically in compensation for the sinking syncline. During the accumulation of the sediments in the syncline, according to Hall, the bottom strata would gradually become stretched and rent with fractures, while from time to time in the upper or younger deposits a folding movement would take place, making land areas which sooner or later were eroded to sealevel and may or may not have become buried beneath subsequent seas. Hall distinctly stated that the folding of strata seemed to him to be ®* Joseph Le Conte: On the formation of the features of the earth surface. Amer. Jour. Sci. (3), vol. 5, 18738, p. 450. 6 Le Conte: Op. cit., p. 451. £56 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES me “a very natural and inevitable consequence of the process of subsidence.’ He denied “the influence of local elevating forces and the intrusion of ancient or plutonic formations beneath the line of mountains, as ordi- narily understood and advocated.” He goes on to say :* “The sinking down of the mass produces a great synclinal axis; and within this axis, whether on a large or small scale, will be produced numerous smaller synclinal and anticlinal axes. . . . I hold, therefore, that it is impossible to have any subsidence along a certain line of the earth’s crust, from the ac- _ cumulation of sediments, without producing the phenomena which are observed. in the Appalachian and other mountain ranges.” According to Hall, therefore, the internal structure of folded moun- tains was made during the accumulation of the strata in compensation: for differential movements of the formations while they were sinking, and not through lateral thrusting of an eastern inwardly moving land. It further appeared to him that folding had contributed nothing to the altitude of mountains. Later on, however, the loaded and folded marine: area was subjected to continental elevation in a vertical direction (epeiro- genic), and the elevating was highest in the area of thickest sedimentary accumulation. Hall did not say why the continent was vertically elevated, since his: views were not a theory of mountain-making, but he held that “mountain ranges were coincident with lines of great sedimentary accumulation,” and that “this accumulation of sediments, with its subsidence and conse- quent folding and plication and the subsequent elevation of the mass and erosion of the anticlinals, had shaped the mountains.” Further, “that the mountain elevations were never equal to the vertical thickness of the strata composing them. I intended to imply that mountain elevation was due to sedimentary accumulation and subsequent continental eleva- ion? * DANA ON GEOSYNCLINES, SYNCLINORIA, AND ANTICLINORIA It is apparent from the above that the theory of geosynclines, as we now hold it, had its inception in the idea of trough or syncline areas of sedimentation as set forth in 1857 by Hall. This was, according to Dana, “the first statement of this grand principle in orography.” Then the theory lay more or less dormant until 1873, when Dana showed? that the great subsidences of the globe have not been made by the gravity of ac- 7 Paleontology of New York, vol. 3, 1861, p. 70. 8 James Hall: Proc. Amer. Assoc., vol. 31, 1883, p. 68. 9James D. Dana: On some results of the earth’s contraction from cooling, including” a discussion of the origin of mountains, and the nature of the earth’s interior. Amer. Jour. Sci. (3), vol. 5, pp. 423-443; vol. 6, pp. 6-14, 104-115, 161-172. RISE OF THE THEORY OF GEOSYNCLINES 7 cumulating sediments, an explanation which, he states, is “wholly at variance with physical law.” It was at this time that Dana introduced the term geosynclines for what Hall had called synclines, because they do not have the simple synclinal structure, but are made up rather of “many true or simple synclinals as well as anticlinals.” The mountain system that eventually rises out of a geosyncline, Dana at the same time called a synclinorium. In other words, synclinorial mountains arise sub- sequently, through folding due to lateral compression, out of the strata of a geosyncline. “The term thus introduced by Dana has, unfortunately, been diverted from its original meaning and applied to a general syncline Compounded of minor folds and contrasted with anticlinorium. It has thus become a term of struc- ture, and the related idea of mountain-making, which the name expresses, has been relegated to a subordinate position, or entirely left out.” * “The geosynclinal ranges or synclinoria have experienced in almost all cases, since their completion, true elevation through great geanticlinal movements, but movements that embraced a wider range of crust than that concerned in the preceding geosynclinal movements—indeed, a range of crust that comes strictly under the designation of a polygenetic mass.” In other words, ‘‘Moun- tain chains are combinations of synclinoria and of anticlinorian elevations.’ % Dana in 1895 says further :” “The great facts to be explained in a theory of mountain-making relate (1) to the preparatory geosyncline or trough and its load of strata for the moun- tain structure; (2) to the mountain-making events—the upturning, flexing, and faulting of the strata, and all other effects of the movements in progress. On any theory of origin, such mountain ranges are synclinoria, as they have been termed by the author, from the Greek for syncline, and épos, mountain, they having had their beginning, as first recognized by Hall, in a preparatory geosyncline of accumulation. The geosyncline occupied the area of the future mountain range.” TRO KINDS OF GEOSYNCLINES IN NORTH AMERICA Just as there are several categories of geanticlines, so there are at least two types of geosynclines, some (1) with comparatively short and simple histories, like the Acadian and Saint Lawrence troughs, or with longer histories, like the Franklinian; and (2) others, very extensive in time and space, having undergone long and complicated evolutions, as did the Appalachian and Cordilleran (see maps, figures 1 and 3). In America, where the theory of geosynclines arose, the idea is typified by the structure of the Appalachian-Allegheny area, and it is admitted 107. V. Pirsson: Text-book of geology, Pt. I, Physical geology, 2d ed., 1920, p. 306. 1i Dana: Op. cit., pp. 432, 171. 122 Dana: Manual of geology, 4th ed., p. 380. 158 Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES by every one, at least tacitly, that this geosyncline has always been a part of the North American continent. In other words, the Appalachian geo- syncline has never been a part of the oceans or mediterraneans, nor does it, like the mediterraneans, lie between continents (see page 194). Fur- thermore, as the loading of this geosyncline did not make it subside, it follows that there must have been another crustal element orogenetically connected with it. This was, of course, the outer, mobile, progressively rising borderland, Appalachia, which finally became a highly elevated anticlinorium, delimiting the Appalachian geosyncline on the west and shedding into it most of its sediments. The Appalachian-Allegheny Mountains are, therefore, a combined synclinorium and anticlinorium, or, as Dana would say, a “‘polygenetic mass.” BorRDERLANDS OF NortTH AMERICA (See Map, Figure 3) GENERAL DISCUSSION From the geographic position of the geosynclines near the margins of the continent, and the further fact that the main masses of their sedi- ments came not from the medial area of the continent, but from more or less narrow lands facing the oceans, it is clear that North America was originally much more extensive than now. Since these facts are already true in Lower Cambrian time, it is also clear that the extent of greater North America was established in Proterozoic time. Even throughout the later Proterozoic we see the presence of a Cordilleran geosyncline in the same general area as the seaways of the early Paleozoic, and it follows that greater North America came into existence at least in early Pro- terozoic time. The present area of North America is over 8,300,000 square miles and Greenland has in addition about 850,000 square miles. In Proterozoic time, on the other hand, the writer believes that greater North America had an area, of over 11,000,000 square miles; that since then Greenland has become a separate land, and that in addition some 2,000,000 square miles of the continent have been warped and fractured into the oceanic realms. These statements are portrayed on the map, figure 2. | Almost the entire outer areas of North America show in their geologic structure that a more or less wide belt has been the most mobile part of the continent. At various times these marginal lands have periodically risen into more or less high lands, and they have been the main source for the sediments of the geosynclines situated along their inner ‘sides. On the outside of the borderlands lie the permanent oceanic basins. How BORDERLANDS OF NORTH AMERICA 159 far these lands once extended beyond the present shorelines into the oceans is unknown, but it is certain that much of their outer portions have been fractured into the ocean depths. The present continental shelves are therefore held to be of fairly recent origin—of late Cretaceous making along the Atlantic and of late Cenozoic origin on the Pacific side of the continent. - The topographically more or less high borderlands of North America— the frame surrounding the inner basin—are periodically raised, and this appears to be due to a shrinking earth. The earth is continually cooling, though seemingly at an excessively slow rate, through internal magmatic differentiations ; it is also losing gases and water, while the centrosphere is in molecular rearrangement, due to the great attraction pressures of the earth’s mass; and because of these changes the earth shrinks in yol- ume. The outer lithosphere, on the other hand, is stiff, rigid, and very strong, and hence long resists the shrinking of the centrosphere. Peri- odically, however, its resistance is overcome, and then crustal shortening takes place, mainly in the areas of weakness, the geosynclines. Since the oceanic basins occupy about two-thirds of the earth’s surface and their mass averages about 3 per cent heavier than that of the conti- nents, the areas of these basins are the main subsiding ones of the earth. During the subsidence, there is, according to theory, also some deep- seated rock flowage, and especially near the junction areas between oceans and lands. This flowage differentiates out lighter masses, and these hot magmas make their way, along with great pressures, tangentially upward into the borderlands, raising them into the frame of the continents. It is these periodically compensating and inwardly moving masses of the more mobile lower part of the lithosphere that cause the thin, cold, and rigid supercrust or stratosphere (also tectonosphere) to fold and over- thrust toward the neutral areas. On the other hand, the rising granitic magma may dominate in its movements, ascending like a vertical wedge into the supercrust, thrusting it aside into a bilaterally symmetric moun- tain chain. - North America is margined on the east by Novascotica, Appalachia, and Antulia. Hach one of these borderlands has its own geologic structure and history. Along the west coast of North America is the greatest of all the borderlands, Cascadia, which later on divides into California and Char- lotte masses (from Queen Charlotte Islands). Yukonia, occupying a great part of present Alaska, is not well enough known to say much about it, other than that in this area the seaways’seemingly show that there often was a borderland here. Mexico, or Columbia, in Paleozoic time appears to have been a lowland and apparently with the characteristics 160 Cc. SCHUCHERT——_THE NORTH AMERICAN GEOSYNCLINES of a nuclear area, but in Permian time its western half became rugged or mountainous, with a geosynclinal sea over the eastern portion. It therefore appears to be a nucleus that has undergone a second cycle of crustal deformation. -Llanoria, on the other hand, even though but a northeastern extension of Mexico during much of the Paleozoic, yet has its own history, apparently becoming actively mobile and mountainous for the first time late in the Mississippian. Finally, Arctic America is bordered by Pearya, part of which is now risen into the United States mountains. These borderlands are plotted on the map, figure 3, and the more important ones will now be described in more detail. APPALACHI4 As long ago as 1856** Dana defined Appalachia as “the region toward the Atlantic border, afterward raised into the Appalachians,” but the actual name for the borderland was not given until 1897, and then by Williams.** In the present connection, we will restrict the term Appa- lachia to the southern half of the eastern borderland lying to the north and west of Antillia; the northeastern borderland has long been known as Acadia, of which Novascotica is the outer portion (see page 162). The western margin of Appalachia extends from about the highlands of New York southwestward into central Alabama, where this old land is overlapped along its inner side and southern end by Mesozoic and Ceno- zoic deposits. Across its eastern side the Atlantic Ocean began to spread for the first time in the Cretaceous, and it continued to do so periodically during the Cenozoic. How far this borderland formerly extended into the Atlantic Ocean may never be learned, even approximately, but en the basis of the very thick Devonian clastics of the Appalachian geosyncline extending from central Virginia to the Catskills, Barrell*® estimated that their volume is at least 63,000 cubic ‘miles, or considerably more than the volume of the Sierra Nevada of California. On this estimate of sediment that was clearly derived from a highland to the east and southeast, and on the assumption that this land had the height of the present Sierra Nevada, Barrell concluded that the watershed of Appalachia in Devonian time was where the 100-fathom line of the Atlantic is now: in other words, roughly 100 miles east of New Jersey. Therefore, if the eastward slope of the watershed was like the western one, Appalachia extended out into the ocean at least 200 miles beyond the present shoreline of the At- 13 Dana: On American geological history. Amer. Jour. Sci. (2), vol. 22, p. 319. 14H. S, Williams: On the southern Devonian formations. Amer. Jour. Sci. (4), vol. 3, p. 394. 1 Joseph Barrell: Upper Devonian delta of the Appalachian geosyncline. Amer. Jour. Sci. (4), vol. 37, pp. 248-249. BORDERLANDS OF NORTH AMERICA 161 lantic. Since this estimate is based on clastics alone, it is probable that Appalachia extended eastward even farther than 250 miles. This land began to founder into the depths of the Atlantic (Poseidon) seemingly as early as the Jurassic period. ~ Was Appalachia during Paleozoic and Mesozoic times continuous with Antillia and the Bahamas? Our knowledge of dated geologic formations in Antillia does not go back of the Jurassic, and so we are left to guess what the earlier relations were. From the maps already shown, it has. been seen what shape my guessing has taken. The extent of these lands is, however, circumscribed by the depths of the present oceans and the nature and distribution of the Paleozoic faunas. In any event, what- ever the area and the outward form of Appalachia, it was not an inde- pendent continent ; rather was it an integral part of North America. The importance of this conclusion will become apparent when we contrast geosynclines with mediterraneans (see page 194). Later on it will be shown that to the southeast of the Saint Lawrence geosyncline lay another one, the Acadian trough (page 179). 'The ques- tion must now be asked, Was there also a geosyncline to the east of the Appalachian one? Our answer is that there is nothing in what remains of the western part of Appalachia to show that such a trough ever existed in this borderland. Much further than this we can not go, but from Barrell’s physiographic studies of Appalachia in Devonian times it is clear that if another geosyncline was present it must have lain upward of 200 miles east of the eastern shore of the Appalachian geosyncline. Keeping in mind the present depths of the Atlantic Ocean, however, we are disposed to believe that Appalachia was throughout a highland and of the nature of a geanticline. As Appalachia furnished nearly all of the sediments of the geosyncline that lay along its western side, we must now try to find out how often this land was reelevated. It is clearly evident that southwestern Appa- lachia was mountainous in earliest Cambrian time. This is seen in the immensely thick, and at first very coarse, Lower Cambrian formations of the Appalachian trough, extending from Tennessee into’ Alabama. Other thick clastic deposits extend northeastward in decreasing volume to New Jersey. On the other hand, clastics in thick deposits of late Ordovician and early Silurian age increase in volume from Virginia to southeastern New York. The Silurian is also very thick and in coarse deposits in the Maritime Provinces of eastern Canada, indicating that early in the Silurian Acadia was also in highland condition. 162 c.SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES The Lower Devonian sandstones are also widespread and extend from Georgia to New York. Their thicknesses, however, never exceed hun- dreds of feet, and accordingly Appalachia is not thought to have been reelevated much at this time. In keeping with the orogeny of middle and late Devonian times throughout Acadia, we see in the very extensive and thick Devonian delta deposits of the Appalachian trough that northern Appalachia was then -also a highland and not very unlike the Sierra Nevada of today. Toward the close of the Mississippian, Appalachia was again reelevated, and the proof of it lies in the 10,000 feet of coarse deposits of the coal ‘fields of Alabama, the widely distributed and thick Pottsville conglom- erate and sandstones, and the general sandy nature of the thick deposits of Pennsylvanian time. On the other hand, we may conclude from the very thick accumula- tions of Paleozoic sediments in Pennsylvania, ranging between 30,000 rand 40,000 feet in thickness, that Appalachia was several times a high- land during Paleozoic time. This generalized statement is further sup- ported by the folding of the western side of northern Appalachia and ‘presumably also of Acadia in Ordovician time, and by the very marked folding of Acadia in the late Devonian; further, the presence in the Appalachian geosyncline of thick sandstones of Lower Devonian and early Pennsylvanian ages shows that there was reelevation of the border- lJand at the close of Silurian and Mississippian time. Therefore, directly or indirectly, the evidence indicates that Appalachia was reelevated about six times during the Paleozoic, namely, (1) at the very beginning of the ‘Cambrian, (2) late in the Ordovician, (3) somewhat during the Lower Devonian, (4) in the Upper Devonian, and (5) at the close of the Mis- sissippian. Finally, (6) in the Permian came the greatest of all the crustal movements, when the borderland and the geosyncline were folded into an anticlinorium and synclinorium that together make the Appa- lachian Mountains, of which today we see only the roots beneath the dissected Cenozoic peneplain. ACADIA AND NOVASCOTICA The northeastern half of greater Appalachia, properly greater Acadia, includes the Acadian geosyncline, the New Brunswick geanticline, and the borderland Novascotica. The latter is the homologue of restricted Appalachia, and all that is left of it as dry land is a narrow strip of its inner side making up the greater part of present Nova Scotia and Cape Breton. The banks outside of these provinces and of Newfoundland are BORDERLANDS OF NORTH AMERICA 163° but the submerged portion of this borderland. The width of Novascotica. is unknown, but it seemingly was not less than 150 miles and may well have been of the order of 250 miles. Novascotica appears to have been reelevated during the first half of the Paleozoic at least five times: first, decidedly toward the close of the Cambrian, as is shown in the thick and coarse clastics of earliest Ordo- vician time; secondly, during the last half of the Ordovician, when the Acadian trough was dry; thirdly, at the close of the Ordovician, as is’ attested by the thick deposits of the Silurian; fourthly, toward the close of the Silurian, when the reelevation was not decided, as seen from the: thin but coarse materials of the Lower Devonian; fifthly, toward the close of the Devonian, as attested by the coarse clastics of the younger Perry and Horton series. Finally, it seems probable that Acadia during Pennsylvanian time was elevated four times more, as is clearly the case for the Northumberland basin. Im all, then, this or that portion of Acadia rose nine times during the Paleozoic. CASCADIA Itsappears probable that Paleozoic Cascadia extended from southern: California far into the north, even beyond the Queen Charlotte Islands. On the other hand, it must also have extended many hundreds of. miles to the west of the present shoreline of the Pacific Ocean, since it fur- nished the thick deposits of the Cordilleran geosyncline. There is, how- ever, from time to time much uncertainty as to the exact position of the eastern shorelines of Cascadia. These uncertainties are due to the fact: that but little of this vast area has been studied in detail and geologically mapped, and our knowledge is still in the main that of reconnaissance: work. Dana included in the borderland Cascadia the Sierra Nevada, Coast, and Vancouver mountains, and the ranges of western British Columbia; in fact, this entire region exhibits but rarely any sediments of Paleozoic age previous to the Pennsylvanian. This and the further fact that the: sediments of the Cordilleran geosyncline thicken and become coarser to: the west are the basis for postulating the long borderland Cascadia. It is generally assumed that Cascadia was a long north-south trending continuous land, and it may have been so throughout the Proterozoic and up to the close of the Ordovician and even the Silurian. With the De- vonian, but more especially in the Carboniferous, the occurrences of marine strata across parts of Cascadia are such as to indicate that even as early as these times this borderland consisted of at least two parts, the 164 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES strike of which is northwest-southeast, in harmony with the present trends of the Pacific system of mountains in California-Oregon, and again in Vancouver-British Columbia. In any event, there were, since the Tennesseean, northwesterly trending channels across Cascadia, the Shastan channel in the south and the Alexandrian embayment in the north, dividing Cascadia into a smaller southern mass that may be known -as the Californian borderland, and a much longer northern one that may be called the Charlotte borderland (see figures 3, 9, and 13). There is as yet no evidence to show that Cascadia as a whole underwent ‘marked orogeny at any time until near the close of the Jurassic, although in the late Devonian there was orogeny going on, together with volcanic ‘action, in northern California. Diller has shown that here the Tennes- seean lies with an angular unconformity on the Devonian. On the basis of the sediments of the Cordilleran geosyncline, however, it is clear that Cascadia must have been a highland during the Proterozoic and again in early Cambrian time. ‘Toward the close of the Cambrian it was a low- jJand and remained so until early Carboniferous time, when it was reele- vated to furnish the moderately thick formations of the Tennesseean and Pennsylvanian formations. MrpIAL OR NUCLEAR AREA OF NortTit AMERICA (See Map, Figure 3) GENERAL DISCUSSION Along the inner sides of the borderlands lie the several comparatively ‘narrow geosynclines, whose waters extended at times irregularly over the medial area of the continent, the very extensive and ancient nucleus of North America. The structure of this medial area came into being long before the Cambrian, and in the main during the earlier Proterozoic, though mountains arose here as late as late Proterozoic time (Killarney Mountains).*® It was therefore the oldest part of the continent, made stiff and rigid through a vast amount of orogeny. Ever since the Pro- terozoic the nucleus of the continent has lain but little above sealevel, warping periodically up or down some hundreds of feet. Repeatedly, shallow seas have formed over parts of it, and yet in no place have the Paleozoic sediments accumulated to a depth of one mile. Usually these strata are measured in hundreds of feet rather than in thousands. Be- cause the nuclear part of North America has remained so near sealevel 1 W. H. Collins: An outline of the physiographic history of northeastern Ontario. Jour. Geology, vol. 30, 1922, pp. 206-207. MEDIAL OR NUCLEAR AREA OF NORTH AMERICA 165 it is also known as the neutral area. JXober has recently called these parts of the continents “Kratogens” (from kratos, strength, and genos, produc- ing). Suess has called these neutral areas forelands, and it is against them that the geosynclines have been pushed and folded. ~The Canadian shield occupies the greater northern part of the neutral region, while in the United States the Paleozoic seas more often covered its southern extension west of the Cincinnati geanticline and east of Siowa, which was less often warped beneath the ocean level (see figure 3). In the late Paleozoic, neutral Siouia, however, became mobile again and the site of the Ancestral Rocky Mountains geanticline (see page 186). The ancient land Columbia, or greater Mexico, may have been another shield, and during most of the Paleozoic it appears to have been a low- Jand, furnishing but little sediment to the adjacent seas. It is most often around, and rarely across, the nuclear region that the inland or epeiric seas have flowed. Because this region has not under- gone orogeny since the Proterozoic, its Paleozoic and later strata remain nearly horizontal, though in places blocks have been faulted or warped into the old masses. Accordingly, all of the flat-lying sedimentary for- mations around and upon the nucleus are included under the term “neu- tral portion of the continent’’—neutral in relation to the average levels of the oceans because unaffected by mountain-making forces. SWELLS Undoubtedly there are many domed areas within the neutral or nuclear areas of North America, and especially within the eastern United States. In Middle Ordovician time the Cincinnati geanticline began in two swells, the Nashville and Cincinnati domes. In early Middle Silurian time these became confluent into a single arch having the general trend of the Appalachians. The Ozark dome is one of the greatest and most persistently rising of these swells, and northern Wisconsin is another but less actively rising one. The Mississippian seas have repeatedly flowed between these swells and at times have completely gone over them. On the other hand, the Sioux Falls region of southeastern South Dakota and the Baraboo range of Wisconsin are persistent Huronian quartzite ridges, remnants of the Killarney Mountains that rose in late Proterozoic time. The buried granite ridge (Nemaha Mountains) also appears to be of this orogenic entity. 166 Cc. SCHUCHERT—_THE, NORTH AMERICAN GEOSYNCLINES GEANTICLINES (See Map, Figure 2) DANA’S VIEWS Having seen that “synclinoria were made through a progressing geo- synclinal,” we are brought, Dana states,’ “to another important distinc- tion in orographic geology—that of a second kind of monogenetic moun- tain.” These are produced through evolving geanticlines, which “are simply the upward bendings in the oscillations of the earth’s crust—the geanticlinal waves,” or “antichnoria.”’ His typical example is the Cin- cinnati arch, though it is perfectly clear that later on he included far greater and even continental (epelrogenic) arching under the term anti- clinoria. Beginning with simple, depressed, and restricted arches, the term came to be apphed by Dana to all upward archings of lesser and greater extent. “Geanticlines and geosynclines.” Dana states,% ‘fare flexures of the strata of the earth’s exterior, or the supercrust, not of the crust itself. The crust is thick, and it is impossible, were it but 10 miles thick. that it should be bent into so small and abrupt flexures. It has, however, its own great flexures of low angle and of great breadth, both upward and downward.” CINCINNATI GEANTICLINE The Cincinnati uplift of Newberry and Safford, and the Cincinnati plateau of H. S. Wilhams, was defined by Dana in 1890?° as the type example of a geanticline. It has in a general way the strike of the Appa- lachian folds and was at times overlapped in part or wholly by the Appalachian or Mississippian seas. When the medial part was submerged, the northern end made Cincinnati Island and the southern one Tennessee Island. As two swells, the arch appeared in Middle Ordovician time, was repeatedly reelevated, and during the middle and late Paleozoic con- tinued as a marked structural feature of the Mississippian seas. It had a width of something like 250 miles. NEW BRUNSWICK GEANTICLINE To the south and east of the Saint Lawrence geosyncline lay the New Brunswick geanticline, separating it from the Acadian trough. This geanticline appears to have originated at the time when the Saint Law- 17 Dana: Amer. Jour. Sci. (3), vol. 5, 1873, p. 432. 8 Dana: Manual of geology, 4th ed., 1895, p. 106. 19 Dana: Areas of continental progress in North America. This Bulletin, vol. 1, p. 41. Also Manual of geology, 4th ed., 1895, p. 387. GEANTICLINES 167 rence and the Acadian geosynclines on either side of it came into exist- ence, namely, toward or at the close of the Proterozoic. This axis, begin- ning in the granitic area of eastern Connecticut and Rhode Island, continues across central Massachusetts into New Hampshire (the White Mountains are situated on it), thence northeasterly across central Maine into northern New Brunswick, and finally across southern Newfoundland. The width of this geanticline appears to have been on the average greater than 100 miles. How often the New Brunswick geanticline was in upward motion is not yet known. If, however, we may judge by the nature of the coarse sediments in the Saint Lawrence trough, it appears to have been rejuve- nated into a highland (1) toward the close of the Cambrian (seen in the Lauzon quartzites and conglomerates, the red Sillery, and the green Que- bee slates) ; (2) during the later Ordovician (seen in the coarse Cincin- natian and early Silurian formations); and (3) by the long-continued intermittent rising during late Silurian and middle Devonian time, which ended in the Gaspé sandstones, 7,000 feet thick. The Ancestral Rocky Mountains geanticline and the Cordilleran Inter- montane geanticline are best described in connection with the Cordilleran geosyncline (see pages 186-187). KINDS OF GEANTICLINES The several geanticlines or anticlinoria of North America can be grouped in three categories: Those of lesser import are (1) the low, narrow, localized arches in the interior of the continent, typified by the Cincinnati arch. The most mobile of the anticlinoria are (2) the peri- odically rising borderlands, such as Appalachia, which border the geosyn- clines oceanward. ‘They have been described on preceding pages and need no discussion here. Then there are (3) the geanticlines that rise out of the area of a geosyncline and have seas on either side of them, as the New Brunswick, Ancestral Rocky Mountains, and Cordilleran Intermon- tane geanticlines. Geanticlines may have no direct connection at all with folded moun- tains, as in the Cincinnati arch. In other cases a geanticline is situated on one side of an orogenic mass, as the Front Ranges of Colorado lie in front of the Rocky Mountains. In yet other cases folded mountains are present on either side of a geanticline, as the Sierra Nevadas and the Rocky Mountains on either side of the Cordilleran Intermontane geanti- cline. The latter appears to be the equivalent of the “Narben” and the “Zwischengebirge”’ of Kober’s Alpine orogen.?° Geanticlines and orogens 20. Kober: Der Bau der Iirde, 1921, p. 140. XIJI—BULL. GEOL. Soc. AM., Vou. 34, 1922 168 C. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES may remain as dry lands or may sink into the depths of the oceans, as in the Dutch East Indies. Finally, we must note the greatest upbowings of the continents that result from epeirogenic movements. These were first defined by Dana and Gilbert as the very broad and flat archings that appear long after folded mountains are made, the uplift affecting at the same time both synclinoria and anticlinoria and even parts of the far inland neutral regions.. Such are the greater Appalachian uplift extending from the Atlantic Ocean to the Mississippi Valley, and the far vaster and higher Rocky Mountain arch extending from Kansas and Nebraska to the Pacific Ocean. The latter came into existence after the Miocene, and its crest is between 5,000 and 7,000 feet above sealevel, on the top of which are situated the protuberant remainders of the previously made synclinoria and anticlinoria. PROTEROZOIC GEOSYNCLINES (See Map, Figure 1) When it became apparent that the Cordilleran and Appalachian geo- synchnes were in existence in earliest Cambrian time, it was thought desirable to learn when they originated. The writer therefore took Van Hise’s correlation papers for the Archean and Algonkian** and plotted on a map of North America the late Proterozoic deposits (Keweenawan and Animikie). Copies of this map were then sent for criticism to the following geologists in this country and Canada: Arthur Keith, Eleanora Bliss Knopf, Anna I. Jonas, Edward Sampson, D. F. Hewett, F. J. Alcock, C. K. Leith, and J. J. O'Neill. The map (figure 1) here pre- sented is the result of this assistance, for which the writer is very thank- ful. The shorelines as plotted must, of course, be conjectural, and all that is really valuable is the general trends and positions of the four sea- ways: (1) Appalachian, (2) Cordilleran, (3) Ontarian, and (4) the greater Arctic sea. The southern opening of the Appalachian geosyncline and the southern and northern ones of the Cordilleran troughs are also highly conjectural. It may be that Daly’s northern continuation of the latter waterway into the Arctic Ocean?? is more correct than that shown in figure 1 of this address. The Cordilleran geosyncline is the longest enduring trough and came into existence early in the Proterozoic. During this era there was de- 21C, R. Van Hise: Correlation papers—Archean and Algonkian. U, S. Geol. Survey, 3ull. 86, 1892. “RR. A. Daly: Geology of the North American Cordillera at the-forty-ninth parallel. Geol. Survey Canada, Mem. 38, 1913, p. 202. PROTEROZOIC GEOSYNCLINES 169 posited here a maximum depth of more than 37,000 feet of strata, though the individual sections range in thickness from 10,000 to 27,000 feet. There are almost no volcanic materials. The formations are distinctly bedded clastics, with practically no conglomerates, composed chiefly of fine-grained sandstones and shales with a moderate amount of impure limestone and dolomites that contain considerable iron carbonate and silica.2* They are all shallow-water deposits, the argillites are often banded, rippling and mud-cracking are common, and sometimes also salt crystals. Purple and red colors are not common, the prevailing shades being greenish, bluish, grayish, or whitish tints. Basal conglomerates occur only to the west, and Schofield?* says that the sandstones become coarser in the same direction; therefore a land lay to the west. This is the borderland Cascadia, which came into existence probably earlier than the Cordilleran geosyncline. ‘Toward the top of the Beltian series in southern British Columbia occur 300 to 5,000 feet of lavas and sills. Toward the top of the Beltian series, in association with the limestones and dolomites, algal deposits (Cryptozoon-like forms) are common and at times make up thick beds. Walcott?® has also described annelid tubes, and to the writer these fossils suggest marine waters rather than fresh or even brackish ones. In northeastern Utah the Uinta reddish (ferruginous) quartzites with some greenish shales are, according to Powell,?® 12,500 feet thick. They rest unconformably upon Archeozoic formations. In the Grand Canyon of Arizona occur, according to Walcott,?* 12,000 feet of more or less red strata, beginning at the top with the Chuar.sandy shales (5,120 feet). Below are the Unkar sandstones and sandy shales (6,830), with some calcareous shale and limestone below (435), along with lava flows in the upper part. All of the Grand Canyon series is near-shore deposits and much of it is even of fresh-water origin. The sediments came from the north and west. In the southern Appalachian geosyncline Keith informs the writer that the late Proterozoic formations consist of lava flows, tuffs, and slates, the flows predominating at the northwest, where land is therefore indicated. *F. C. Calkins: A geological reconnaissance in northern Idaho and northwestern Montana. U.S. Geol. Survey, Bull. 384, 1909. 4S. J. Schofield: Geology of the Cranbrook map-area. Geol. Survey Canada, Mem. 76, 1915. 2° C. D. Walcott: Pre-Cambrian Algonkian algal flora. Smithson. Misc. Coll., vol. 64, 1914, pp. 77-156; Pre-Cambrian fossiliferous formations. This Bulletin, vol. 10, 1899, pp. 199-244. *6 J. W. Powell: Report on the geology of the eastern portion of the Uinta Mountains. U. S. Geol. and Geog. Survey Terr., vol. 7, 1876. * C. D. Walcott: Pre-Carboniferous strata in the Grand Canyon of the Colorado, Ari- zona, Amer. Jour. Sci. (3), vol. 26, 1883, pp. 437-442. ECO C. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES In the Pennsylvania-Maryland area they make up the Glenarm series, and in New York the equivalent formations are the Lowerre, Inwood, and Manhattan (Jonas). The thickness is something like 10,000 feet. In Nova Scotia the Gold-bearing series consists of a lower quartzite group about 11,000 feet thick and an upper graphitic and ferruginous slate group about 4,000 feet in depth. In southeastern Newfoundland the Proterozoic series is over 11,000 feet thick, and consists of coarse quartzites, slate conglomerates, slate, and diorites. The Ontarian geosyncline (so named because best developed in Ontario Province) embraces the Animikian, or Iron series, of but little disturbed, dark, carbonaceous (6-10 per cent) slates and sandstones, with iron- bearing chert and jasper and impure limestones and dolomites. In the Penokee area of Michigan the portions remaining have a thickness of 14,000 feet, but elsewhere they are much thinner. These strata are held to be of marine origin. The Animikian series is followed by the Keweenawan sediments, usually of a red color, and metal-bearing volcanics (seemingly plateau flows, largely diabase and basalt). In the Lake Superior region the lower conglomerates and sandstones, with impure limestones and shales, have a thickness of from 300 to 1,400 feet. They may be of marine origin. Then comes the middle series, probably wholly of continental origin and upward of 30,000 feet thick, of which at least five-eighths is igneous material, the rest being red conglomerates and sandstones. The upper series attains locally to 20,000 feet, most of which is sandstone of fresh- water origin, derived from the volcanics. The Ontarian geosyncline is the oldest known trough of North America. It probably had its origin during Archeozoic time, since all of the older Proterozoic deposits, and even the Grenville series of Ontario, likewise have the alignment of the younger series. The greater Arctic sea is not regarded as a true geosyncline. The sediments are largely sandstones, with some slate. It is interesting to note this late Proterozoic marine invasion, since it recalls the four similar floods of Ordovician and Silurian times. DEVELOPMENT OF THE APPALACHIAN GEOSYNCLINE (See Maps, Figures 4 to 12) GEOSYNCLINES IN GENERAL In North America the geosynclines all le on the inner or continental side of borderlands (see map, figure 3). Their.deposits are thickest DEVELOPMENT OF THE APPALACHIAN GEOSYNCLINE yey ‘toward the borderlands and thin out over the neutral area or the nucleus of the continent. In the east is the smaller Appalachian geosyncline, and in the western part of the continent the greater Cordilleran geosyn- cline. The latter finally evolves into the Rocky Mountain and Pacvfic sequent geosynclines of Mesozoic times. To the east of the Appalachian geosyncline in greater Acadia is the small Acadian geosyncline. Finally, there is in the Arctic region, on the inner side of the borderland Pearya, the Franklinian geosyncline. EMBAYMENTS Besides these geosynclines, but in connection with them, there is in the southern part of the continent the Ouachita embayment, uniting with the Appalachian geosyncline, while the southern end of the Cordilleran geosvneline has the Sonoran embayment, extending transversely across Nevada, New Mexico, Texas, and Sonora (see map, figure 3). GREATER APPALACHIAN GEOSYNCLINE The Appalachian geosyncline, in the widest sense, extends from the southeastern corner of Labrador and northern Newfoundland along the western side of Acadia and Appalachia into the Gulf of Mexico. At the northeast it appears to have been continuous with what is now the North Atlantic, but during the Paleozoic, with Poseidon, an ocean to the north of the transverse equatorial land Gondwana. At the southwest the trough appears to have continued unbroken into the Gulf of Mexico and across Tehuantepec into the Pacific Ocean. As previously stated, the Appalachian trough was in existence early in Proterozoic time. Beginning with the Lower Cambrian, it appears earliest in Alabama, Georgia, and Tennessee, and long before the close of this epoch the trough was continuous from the Gulf of Mexico northeast to Newfoundland. The deposits of Cambrian time are much the thickest in the southern part of the trough and are from Appalachia, then a mountainous land. On the other hand, in the northeastern part of the geosyncline the sediments are much thinner. It should be said that in the main the clastics throughout the greater Appalachian trough came from the east and southeast. In all of this we see that the isostatic rela- tions of the sinking geosyncline to the rising eastern lands were reestab- hshed during the crustal movements taking place toward or at the close of Proterozoic time. Thus far we have spoken of the greater Appalachian geosyncline as a continuous trough, and so it is from the structural viewpoint; but from the local sedimentary histories it is plain that there are here combined 172 c.SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES two confluent geosynclines, with at times very dissimilar developments © stratigraphically, faunally, and even orogenetically. For these reasons the term Appalachian geosyncline, in the restricted sense, will refer to the trough south of Vermont, while to the one northeastward of Massa- chusetts we will apply the term Saint Lawrence sea, made familar to us by the Canadian geologists and James D. Dana. It should be remem- bered, however, that there appears to be no sharp geographic boundary between them. Furthermore, both troughs during Lower and Middle Cambrian times appear to have spread either confluently or singly across New Jersey and the southern New England States into the Atlantic Ocean (Poseidon). From Upper Cambrian time into the Devonian the two geosynclines were structurally more or less confluent, though their seas were at times not continuous. On the other hand, the Saint Law- rence geosyncline often brought into the interior seas of America parts of north European faunas, while the Appalachian one continued into the Antillean mediterranean, having south European and South American faunal connections. RESTRICTED APPALACHIAN GEOSYNCLINE The sedimentary history of the actual Appalachian geosyncline con- tinued from the beginning of Cambrian to the close of Pennsylvanian time, and it was a far more persistent, longer enduring, and more deeply subsiding trough than the Saint Lawrence geosyncline. Then, too, this periodically subsiding trough was more often filled with variably exten- sive shallow seas, and these at times were continuous with the waters of the Saint Lawrence geosyncline. Previous to the Middle Silurian, the Appalachian seas often spread widely also into the Mississippian sea, but after the completion of the Cincinnati arch the floods were restricted to the eastward of this geanticline. The Appalachian trough was more or less completely drained of its marine waters at least éight times (Middle Cambrian, close of Beekman- town, close of Ordovician, Guelph, close of Silurian, late Devonian, and twice during the Mississippian). It is certain, however, that locally it was dry far more often than eight times, but this matter can be made plain only through a detailed statement of the history of the trough, and this is not the occasion to present the succession of paleogeographies. Sedimentation in the Appalachian geosyncline was by no means con- tinuous nor uniform in the rate of deposition. The Cambrian and Ordo- vician are in best development south of Pennsylvania, while the Devonian is almost restricted to north of Tennessee. The Cambrian and Ordo- DEVELOPMENT OF THE APPALACHIAN GEOSYNCLINES iS vician records are most complete in the south and less so in the north. Then in Middle Silurian time a transverse swell developed throughout eastern Tennessee, and the subsequent seas were far more persistent north of this State than in the southern part of the geosyncline. This swell was especially active in pushing the shorelines to the westward in the area south of Virginia during late Silurian and most of Devonian time. On the other hand, during Middle and Upper Devonian and Mis- sissippian times, the seas again spread eastward to the region of the earlier Appalachian shores. The shoreline was farthest east during the Lower Cambrian and early Ordovician, but it can not be said that it moved progressively to the west with each recurring sea. We have just pointed out the irregularity in position of the eastern shore for the trough south of Virginia. It would, furthermore, appear as if the shore moved irregularly westward for a time, followed, in some cases at least, by a quick return to a more easterly position with the incoming of new seas. Tn any event, we see more easterly shores during Lower Cambrian, Cana- dian, Mohawkian, Lower and Middle Silurian, Middle Devonian, and Mississippian times. During Pennsylvanian time the shore moved pro- gressively to the west, with the final blotting out of the Appalachian trough in the orogenic movements beginning in this period and culmi- nating in the early Permian. From the previous statements we again see what is now so well known, namely, that the transgressions of the oceans upon the continents are periodic in appearance, and more or less irregular in their spreadings. The successive paleogeographies show, however, that the pattern of the seaways is fairly alike—a condition that is governed by the variable moye- ments of the geanticlines and the swells. Nor do the floods always first appear in the Appalachian geosyncline and then spread inland variably over parts of the neutral area. This is true in some cases, but in others the transgressions pass up.the Missis- sippi Valley or down from the Arctic and then extend more or less toward or into the geosynclines. The greatest of Paleozoic floods did not origi- nate in the geosynclines, but came from the Arctic across the western part of the Canadian shield into the United States. This is seen in the floods of the middle and late Ordovician, the earlier Silurian, and again in the Devonian. Rarely did any of these floods fully occupy the eastern geosynclines. In this extraordinary variability of the marine transgres- sions we see that at times the Appalachian geosyncline is above the strand-line while the neutral areas are in flood, and at other times the trough is filled with seas when the interior of North America is land. 174 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES In other words, the sealevel attitude of the neutral area is not always in keeping with the periodic sinkings of the geosyncline below sealevel. Ac- cordingly, there appears to be an irregular alternation between land and sea conditions in the Appalachian, the Mississippian, and the neutral areas. Since the Appalachian trough is the type area on which geosynclinal structures are based, let us look a little more deeply into the local rock quantities and times of sedimentation, so that we may learn more as to the nature of its irregularly subsiding bottom. Accordingly, we will present something of this detailed sedimentation along seven different lines across the geosyncline. (1) Northwest-southeast through Kingston, New York —In this area the maximum of sinking appears not to exceed 15,000 feet. The generalized sec- tion is about as follows: CAI TIAT SS Fe cS a ascents, hear oars ae eS ie yc SIRT Ce Tek SE lyse a et 1,500 OPGOVLCKAA IR See a oe ee Oran 6 Rik a akc a Steal oot a oi El ace 2 auc near ee 4,000 Silurian (Shawangunk, 300; High Falls, 500; Cement series, 35)...... 835 Devonian (Helderbergian, 250; Oriskany, 180: Esopus-Onondaga, 375; Hamilton, 1,300; Portage, 3,000: Chemung, 1,725; eroded away. 500). 7,330 MiSSISSIPPIAH: ‘Croded: AWay <-< 2:56 Sgis.k sists = Angie 3 eee oe ee ee 500 14,165 (2) Northwest-southeast through northern New Jersey.—Here the maximum of sinking appears to be about 23,000 feet. The generalized section is as fol- lows: ) Feet Cambro-Ordovician (Chickies, 1,000; Kittatinny, 3,000)..............: 4,000 Ordovician (Jacksonbure, 150; Martinsbure, 3:000)....:.4.4..2 ..seeeee 3,150 Silurian (Shawangunk, 1.6007 Mish Falls, 2,300) 02... . 0c .5 4s ee eee 3,900 Devonian (Hower; 400% Test? S500) Saas. seas Dee woes oan eee eee 8,900 Massissippian- (Susquehanna: areayon. 5... oc aes cas se 2 2 ee ee 2,000 Pennsylvanian, (Anthracite? areay.as t:s/siis «(2 eines Sanccecee nl sheserar ree eee ee 1,500 23,450 (3) Through Maryland and southern Pennsylvania.—This area appears to be the second greatest subsidence (see 7), and the old Proterozoic land in the deepest part of the trough has gone down about 35,000 feet. The detail is as follows: Feet Lower Cambrian (Antietam, 800; Harpers, 2,750; Weverton, 1,250: Tomstown,: 1,000; Waynesboro. 1,250; ‘Hilbrook,.3:000)........./.0. ee 10,050 Cambro-Ordovician (Conococheague, 1,635; Beekmantown, 2,300)...... 3,955 Ordovician (Stones River, 1,050; Chambérsburg, 750; Martinsburg, POOO ® -Fumiatas OO eee eck eu arete evel’ at ip asin hates over her Sec rOmeate eee 4,200 DEVELOPMENT OF THE APPALACHIAN GEOSYNCLINES Lid Feet Slluman:(Pusearora, 270; Clinton, 920; Cayugan, 1,450)... ........4 2. 2,640 Devonian (Helderbergian, 300; Oriskany, 400; Romney, 1,400; Jennings, ERO mA CAATIOSINITES Ae UU) ) wie lctaislone avec ovals aleve wv ere wipe: aval: a @iela cre we reoes 11,600 Missiccnppian. (Pocono, 1,800; Mauch Chunk, 2,000)... ..00...0.6. 004.08. 3,800 Beansyivanian, 3,100; Permian only in west, 1,200....00..00.%06 060s oe. 4,300 40,525 (4) Through central Virginia and West Virginia—It appears that in this area the trough did not subside more than 25,000 feet. The formations are as follows: 5 Feet OS lal LSD, SOT aN OA AR Nee a aie i a Piel oe RAE a eae 0 ce 8,000 Ordovician (Shenandoah, 2,400; Martinsburg, 2,000; Massanutten- LEE TE TLIC UN Ug SS I ym re cen ea ae 5,400 Silurian (Tuscarora, 600; Rockwood, 700; Cayugan, 700)............. 2,000 Devonian (Helderbergian, 200; Oriskany, 300; Middle, 1,300; Upper, TORT. aie a acG lh AB een RR Vi PARR isl ecg Re nag ee eee a anal 6,800 Mississippian (Pocono, 500; Greenbrier, 1,000; Canaan, 1,200)......... 2,700 eran SIMS AMES HESTON LSE Nite: oye a cael. y Yebizi ols, ce esereveleeaia’ a sajlaneerare Siena 's ace weld wt facdse: as 4,000 28,900 (5) Through northeastern Tennessee and southwestern Virginia.—The sub- sidence here appears not to have exceeded 20,000 feet. The thicknesses are about as follows: Feet Cambrian, 9,000; Ordovician, 6,000; Silurian, 1,000; Devonian, 300; Mississippian, 3,600; Pennsylvanian, 5,000..... Micnets Marines caleahi ete), so OOO (6) Northwest and southeast through Knoaville, Tennessee.—The subsi- dence here is at least 30,000 feet. The thicknesses are about as follows: Feet Cambrian, 18,000; Ordovician, 8,000; Silurian, 1,200; Devonian, 50; Racsiscwnpian, 2.100: Pennsylvanian, 2;000 0... 02.2.0. .60 02 es. see ese ss 91,350 (7) Northwest and southeast through northern Alabama.—Here the subsi- dence is greatest, being around 38,000 feet. The detail is as follows: Feet Cambrian (Weisner, 10,000; Beaver, 1,000; Rome, 800; Conasauga, MeN MIE Pee ya inde etal c oe aktile nsucrc Lis « Gisvere.s wo 2 S83, bee 2d) sit Fae ea alae ae 14,800 eMC (GIONOR., 4.00 TES, a OOU) sevice dydine deeb awa dered cease eee aies 8.000 Simian £200; Devonian, 1,000; Mississippian;.3,250.......... 2.00008. 5,450 Pennsylvanian (Warrior field, 3,500; Cahaba, 5,500; Coosa. 10,000) .... 10,000 38,250 An analysis of the seven sections just given shows that the bottom of the Appalachian geosyncline has subsided in the line of its strike into at 176 C. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES least two major rock basins.?8 In eastern central New York (Albany) the depression is probably somewhere near 8,000 feet. From here south- ward the trough becomes ever deeper, and in western Maryland it ap- pears to have gone down about 35,000 feet. Thence the bottom rises again to the Virginia-Tennessee State line to about 20,000 feet, only to sink rapidly in the Knoxville area to about 30,000 feet and to about 38,000 feet in northeastern Alabama. What has gone on to the south- ward is not ascertainable because of the Mesozoic overlaps from the Gulf of Mexico. Just as the trough bottom evolved in long undulations along its strike, so in transverse directions it became more or less waved. This is best seen in the narrow but long continuance of the very thick Lower Cam- brian deposits in the southern part of the Appalachian geosyncline. Here these strata in the eastern part of the trough attain a thickness of about 15,000 feet, and thin rapidly to the west. The trough in early Ordo- vician time was a far wider subsiding syncline, and in the middle part. of this period the extreme eastern portion appears for a time to have been divided into several long and narrow seaways.’® In the Maryland region the Appalachian sea during Lower Cambrian time was also a nar- row one, and here accumulated about 10,000 feet of strata. Then came wider seas transversely, and they accumulated in their deepest part an- other 10,000 feet during Ordovician and Silurian time. Over all came the great Devonian-Mississippian delta, so ably pictured by Willis and Barrell,*° depositing another two miles’ depth of strata. Finally, in the comparatively narrow Cahaba coal field of Alabama was deposited, ac- cording to Butts,*t 10,000 feet of early Pennsylvanian sediments. In all of this we see that the Appalachian geosyncline during its growtlr evolved along its strike into at least two great basins of deposits, while transversely the trough was variably wrinkled, changing more and more from a simple syncline into a complex geosyncline. These greater undu- lations of the bottom of the trough and of the older Paleozoic formations should not be confounded with the later superimposed foldings due to: °8 Ulrich in his “Revision of the Paleozoic systems,” this Bulletin, vol. 22, 1911, p. 562, divides the Appalachian geosyncline into five basins, as follows: (1) northeastern Pennsylvania, (2) Maryland, (3) central Virginia, (4) Tennessee, and (5) Alabama. 29 See Ulrich: Op. cit., p. 412. 8° Bailey Willis: Paleozoic Appalachia, or the history of Maryland during Paleozoic time. Maryland Geol. Survey, vol. 4, 1902, pp. 23-98. Joseph Barrell: Op. cit. 31 Charles Butts: The southern part of the Cahaba coal field, Alabama. U. S. Geol. Survey, Bull. 431, 1911, pp. 89-146. Charles Butts and E. O. Ulrich: Mississippian formations of western Kentucky. Kentucky Geol. Survey, 1917, p. 118. DEVELOPMENT OF THE APPALACHIAN GEOSYNCLINES Ae lateral compression, when the geosyncline and the borderland were folded into the Appalachian polygenetic mountains. SAINT LAWRENCE GHEOSYNCLINE (See Maps, Figures 3 to 8) The northeastern half of the greater Appalachian geosyncline, extend-. ing from eastern New York and Massachusetts to east of Newfoundland,, is known as the Saint Lawrence sea. The strata along the northwestern shore of the Saint Lawrence River, and to the west of Lake Champlain as well, still remain undisturbed. They are the materials farthest re- moved from the source of main supply, the highlands of the New Bruns- wick geanticline to the southeast and east. These deposits are chiefly limestones of Cambrian, Ordovician, and Silurian ages and the thick- nesses are usually small. Along the eastern side of the Adirondacks there - is less than 5,000 feet; about Quebec there appears to be less than 1,500: feet; farther northeast, across the Mingan and Anticosti islands, there is about 4,000 feet, and in southeastern Labrador less than 500 feet re- mains. How far these shallow seas spread over the Canadian shield is unknown, since this most positive part of North America has usually been above the strandline and is now stripped of nearly all the marine deposits which once rested on it. Ordovician strata are known, however, about Lake Saint John and elsewhere in Quebec, and since those that remain are of the kinds deposited far from shores, it appears safe to postulate that most of the seas of the Saint Lawrence geosyncline spread several hundred miles to the northwest of the Saint Lawrence River. To the southeast of the great river and estuary, however, all the strata of the Saint Lawrence geosyncline are in greatest confusion, being folded, crumpled, and widely thrusted in superimposed sheets, and intruded by igneous masses nearest the geantichne. ‘This superimposed structure is due in smallest part to the orogeny of late Devonian time, when the trough was, however, completely blotted out; the greatest deformation came with the time of most marked compression and thrusting, during the Pennsylvanian and Permian. All geologists have found it exceed- ingly difficult to unravel the stratigraphic sequence here, and as well to determine the thicknesses of the formations. The greatest thickness of strata appears to be in the Gaspé area, where there may have been as much as 20,000 feet. In northwestern Newfoundland there appears to have been 15,000 feet of subsidence, while to the southeast of Quebec and Mon- treal the formations may attain a similar thickness. In northern Ver- mont the total deposition may not exceed 8,000 feet, and in Massachusetts. 178 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES and eastern New York there seems to be a considerably smaller thickness. In all of this we see that the Saint Lawrence trough was a subsiding area from early Cambrian time to the close of the Devonian, and that nowhere did more than 20,000 feet of subsidence take place. This greater sinking toward the northeastern and oceanic end of the trough was accentuated ‘by the Gaspé delta of Devonian time, where 2,000 feet of limestones and 7,000 feet of sandstones were deposited. The seas of the Saint Lawrence trough at many different times con- tinued confluently into the Appalachian geosyncline. Its sedimentary history is also far less complete than that of the Appalachian trough, and accordingly the whole or the medial length of the Saint Lawrence geo- syncline was oftener dry land; at least five times was it completely drained of all seas. It was dry during the Middle Cambrian and again at the close of the Cambrian, between Beekmantown and Chazy times, and again in earliest and latest Silurian times. It has been stated that the Saint Lawrence trough was blotted out by the late Devonian orogeny. The question must be asked, Were there here earlier times of folding? For three-quarters of a century geologists have been pointing out the Taconic disturbance that took place toward the close of the Ordovician. The area of this folding is known definitely to extend from Tristates, New York, northeastward past Kingston to Becraft Mountain, east of the Hudson River, where all overlapping and definitely ascertained Devonian strata cease. The intensity of folding increases from west to east and from southwest to northeasi.. The dis- tance of known folding in a straight line is about 125 miles, and it ap- pears reasonable to assume that this orogeny extends many hundreds of miles northeast of. Hudson, New York, and to the west of the New Bruns- wick geanticline. As yet the unconformity can not be determined in the intensely folded slates of the Ordovician and Cambrian farther to the northeast. On the other hand, there is not the slightest evidence that Silurian or Devonian formations were ever present on the western side of the Green Mountains, but to the east, of these mountains there is paleontologic evidence of late Silurian, and, in Massachusetts, of Middle Devonian time. These facts appear to indicate that the eastern side of the whole of the Saint Lawrence trough was folded toward the close of the Ordovician. Furthermore, the succeeding Silurian deposits along the southeastern side of the Saint Lawrence trough are thick deposits of sandy shales and impure limestone, indicating that the New Brunswick geanticline had been reelevated. In these occurrences we see that the eastern portion of the Saint Lawrence trough was folded throughout east- DEVELOPMENT OF THE ACADIAN GEOSYCLINE 179: ern New York and perhaps all the way to Newfoundland, where there are also known crustal movements of late Ordovician time. Furthermore, as we shall see later on, the whole of the Acadian trough on the other side of the New Brunswick geanticline was dry land during the middle and late Ordovician. Other local details might be mentioned, all of which point to a time of folding and elevation of the eastern portion of the Saint Lawrence geosyncline extending clearly from New Jersey to Ver- mont and possibly all the way to Gaspé, Quebec. Before leaving the Saint Lawrence geosyncline, it should be stated that the Canadian shield was the northwestern lowland of this trough. Its other shore was the periodically rising New Brunswick geanticline, a. narrow highland tract described earlier (page 166). To the southeast of this geanticline lies another geosyncline, the Acadian trough, next to be described. DEVELOPMENT OF THE ACADIAN GEOSYNCLINE (See Maps, Figures 3 to 8) GENERAL DISCUSSION Across the southeastern margin of the New England States and’ through the central parts of the Maritime Provinces of Canada and southeastern Newfoundland, a geosyncline developed during Cambrian, Ordovician, Silurian, and Devonian times. Dana in 1890*? called it the Acadian trough, and its southwestern end, of longest endurance, the Fundy basin. During its earlier history it extended from at least south- eastern Newfoundland southwestward across Cape Breton, northwestern Nova Scotia, southern New Brunswick, southern Maine, and eastern Massachusetts. Like the Appalachian geosyncline, it appears to have: been in continuance as a trough since early Proterozoic time (see map, figure 1). To the southeast of the Acadian trough lay the borderland Novyascotica, of unknown width, while its northwestern shore was made by the New Brunswick geanticline, which separated it completely from. the greater Saint Lawrence geosyncline. The Acadian trough was present in Lower Cambrian time, and is seen in better development during the Middle Cambrian, with its Paradoxides faunas of Huropean affinities, extending from southeastern Newfound- land to Boston. ‘Then there is no evidence of this trough until early Ordovician time (Bretonian), when again it has decided European faunas. During all the rest of the Ordovician the trough appears to have * Dana: Archzan axes of eastern North America. Amer. Jour. Sci. (3), vol. 39, p.. 380. Also Manual of Geology, 4th ed., 1895, pp. 444, 461, 536. ° 180 Cc. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES been dry land, making its reappearance early in the Silurian (Clinton) -as an open marine channel depositing coarse clastics, and continuing to the end of Guelph time. These Silurian faunas are very much like those of Wales and are best known about Arisaig, Nova Scotia. During the Upper Silurian the sedimentary record is restricted to its westward end, ‘the Fundy basin, laying down here considerable thicknesses of marine strata, but more especially great volumes of volcanic ash and lavas. These center about the southeastern corner of Maine. The Fundy basin ‘continued with marine waters throughout Lower Devonian time, and later in this period the whole of the trough was involved in the marked ‘foldings of the Acadian disturbance. The total subsidence of the Acadian trough apparently did not exceed 12,000 feet (County Antigonish, New Brunswick), though in the very limited and highly volcanic area of southeastern Maine the total smking may have been as great as 25,000 feet. Elsewhere the deposits appear to average around 6,000 to 7,000 feet. The total thicknesses are as follows: Feet ‘Southeastern Newfoundland (Cambrian, 2,120; Ordovician, 3,880)..... 6,000 County Antigonish, New Brunswick (Cambrian, estimated, 1,000; Ordo- vician, 5:800; Silurian, 3,600; Lower Devonian, 680)... .<.....-senee 11,080 Saint John, New Brunswick, and southeast (Cambrian, 2,150; Ordo- vician, 700;:. Silurian. and Devonian,. estimated, 3,500). .!/ 2... «eee 6,350 ‘Eastport, Maine (Cambro-Ordovician, 4,000; Silurian marine, 6,000; Silurian voleanic, 14,000; Devonian, 1,000) 2... ...... 2.2.0. ee 25,000 “Hastern: sMassaenusSenis® | ci..2ce-aa ce Sew ore ea ores toate: els. aw ear 10,600 NORTHUMBERLAND BASIN (See Maps, Figures 10 to 12) With the late Devonian orogeny, as previously stated, the Acadian geo- syncline was blotted out, and then new areas of fresh water with some marine sedimentary accumulation came into being. This embayment, consisting of a series of troughs, may be known as the Northumberland basin because it is best developed throughout the lands bordering the strait of this name in New Brunswick and Nova Scotia. It continued across the Saint Lawrence Gulf and Newfoundland, and the deposits are of Mississippian and Pennsylvanian time. They average in New Bruns- wick and Nova Scotia between 15,000 and 18,000 feet. It is interesting ‘to note that these basins of deposits lie between periodically rising moun- tains, and that these mountains were reelevated four times more before the whole of the Northumberland basin was, in Permian times, brought -above the level of sedimentary accumulation. DEVELOPMENT OF THE ACADIAN GEOSYCLINE . 181 As we have seen, the Northumberland basin came into being with the late Devonian orogeny, which was followed by fresh-water deposition of early Mississippian time (Horton, 2,000 feet) and by late Mississippian marine deposits (Cheverie, 700 feet, and Windsor, 1,200 feet). Then the Northumberland basin underwent mountain-making for the second time, and, so far as known, this movement completely shut out marine transgressions until the origin of the present Gulf of Saint Lawrence. Following this second elevation, more than 5,000 feet of coarse conti- nental deposits of early Pennsylvanian time were laid down in valleys between mountains. Then came the third reelevation of the mountains, followed by 6,800 feet of coarse sediments, also having many coal strata whose floras indicate Middle Pennsylvanian time. Finally came the fourth uplift, giving rise to from 2,100 to 6,000 feet of more or less red ~ beds of latest Pennsylvanian time, and then the whole of the Northum- berland basin was reelevated in the early Permian for the fifth time. In all of this we see that the Acadian region was intensely folded and intruded by igneous rocks during the late Devonian orogeny, and that it then underwent four widely spread times of seemingly vertical uplift, with a final elevation in the Permian. Even so,these are not all of the times this region underwent one or the other kind of crustal movement, since the early Paleozoic formations of the Acadian geosyncline show in the nature of their coarse sediments that the borderland Novascotica had been uplifted in late and early Silurian times, probably also in the Ordo- vician, and at the close of the Middle Cambrian. DEVELOPMENT OF THE OUACHITA HMBAYMENT (See Maps, Figures 5 to 11) One of the interesting phenomena in the stratigraphy of North Amer- ica 1s the appearance in Upper Cambrian time of what seems to be the beginning of a geosyncline all along the north side of the Mexican old land known as Columbia and its northeastern extension, Lianoria. It was a seaway that united the Cordilleran trough with the Appalachian one, but it lasted only into Middle Ordovician time. Beginning in eastern Arkansas, the Cambro-Ordovician deposits of this trough are seen emerging from underneath the Mississippi embay- ment of Mesozoic and Cenozoic formations. They have a maximum thickness of about 1,500 feet, increasing westward to 7,000 feet in the Arbuckle Mountains of eastern Oklahoma (Wichita Mountains have 9,000 feet). Thence southwardly these deposits decrease rapidly in thickness to central Texas, where, in Llano and Burnett counties, the 182 c.SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES depth is about 1,800 feet. In southwestern Texas, about El Paso, the maximum thickness is about 1,700 feet, and a smaller depth continues across southern New Mexico into Arizona. To the south, in Sonora, Dumble has reported about 3,000 feet of limestones beneath supposedly Upper Ordovician formations that may be of Cambro-Ordovician time. On the other hand, while the two ends of this trough (Ouachita and Sonoran embayments), and particularly the former, continued to accu- mulate strata intermittently throughout the Paleozoic, yet the longer central reach across Arizona, New Mexico, and Texas was dry land dur- ing Silurian, Devonian, and Mississippian times. In all of this we see that there was a good beginning for the development of a long transverse syncline, and that it failed to evolve into a geosyncline because the land elements Columbia and Siowia, or the Great Plains country, remained neutral or slightly positive in relation to the oceanic level. In other words, we see that Columbia was not in motion northward; only its north- eastern portion, Llanoria. The latter was a decidedly positive and peri- odically rising crustal element that eventually moved northward, crowd- ing the strata of the Ouachita embayment against the ancient granitic Ozark dome. Because the Ouachita trough had not the usual length of geosynclines, and since it was often dry land, it is preferably regarded as a southwestern embayment of the Appalachian geosyncline. Undoubt- edly the causation for the Ouachita embayment was the decided negative condition of the southernmost portion of the Appalachian geosyncline that was evolving toward a deep Gulf of Mexico. The compensating re- action of this sinking area against Llanoria, on the other hand, caused it to be a decidedly positive element, and especially so after Mississippian time. As we shall see, Lilanoria was the highland that furnished the tens of thousands of feet of clastic sediments for the Ouachita trough of Pennsylvanian time. The Ouachita embayment, as previously stated, emerges from beneath post-Paleozoic deposits at Little Rock, Arkansas, and the petroleum wells ‘about the Wichita Mountains of Oklahoma show that the trough did not extend beyond these mountains. Therefore this embayment had a length of about 400 miles. To the east of Little Rock it must have continued unbroken and in open connection with the Appalachian geosyncline. As is well known, Branner*? long ago pointed out that the Appalachian trough appeared to continue into the Ouachita embayment. It is now certain, however, that the line of strike of the formations of Arkansas ean not be connected with the last of those in Alabama, where the Appa- 33 J. C. Branner: The former extension of the Appalachians across Mississippi, Lou- isiana, and Texas. Amer. Jour. Sci. (4), vol. 4, 1897, pp. 357-371. DEVELOPMENT OF THE OUACHITA EMBAYMENT 183 lachian folds plunge beneath the Cretaceous overlap. The exact stratal connections between these two troughs may never be known because of the very wide Mesozoic-Cenozoic covering of the Mississippi Valley. On the other hand, the Paleozoic faunal connections of the Ouachita embay- ‘ment with those of the Mississippian seas are more intimate than they are with those of Alabama. In other words, the seaway connections on the basis of the faunas are more intimate with the Mississippian sea than with the southern end of the Appalachian trough. The Ouachita embayment appeared early in Upper Cambrian time and its waters remained more or less continuously as a recording seaway into the early Middle Ordovician. The deposits are mainly dolomites, and vary in thickness from 1,500 feet in eastern Arkansas to 7,000 feet in the Arbuckle Mountains of eastern Oklahoma, and to 5,000 feet in the Wichita Mountains, farther west. During Middle Ordovician time the southern end of the neutral area Siouia was warped above sealevel, blotting out the medial reach of the long transverse seaway formerly uniting the Ouachita embayment with the Sonoran embayment, and hence from Mohawkian time onward the former trough is restricted to Oklahoma and Arkansas. From Middle Ordovician time up to the close of the Mississippian, the Ouachita em- bayment was only intermittently filled with marine waters, and therefore during this long interval the deposits are not in great volume. They vary from about 1,200 feet in central Arkansas to about 2,400 feet in the Arbuckles. Then a most marked change took place in the land to the south of the Ouachita embayment, and Llanoria must have been elevated most decidedly, since the Pennsylvanian strata in Arkansas attain, ac- cording to Branner, to a depth of over 23,000 feet. The total maximum thickness of all Pennsylvanian formations in southeastern Oklahoma appears to be about 37,000 feet, though the general average in any place may not exceed 28,000 feet. In other words, the whole of the eastern two-thirds of the Ouachita embayment sank during the Paleozoic no- where less than 25,000 feet, and to the east of the Arbuckle Mountains, the region of greatest depression, it appears to have gone down about 39,000 feet. Shortly after Pottsville time all of the trough in southern Arkansas began to fold into the Massern Mountains. In Oklahoma, how- ever, the folding took place later, and according to McCoy** it came at the close of Monongahela or just before Cisco time. The thrusting is toward the north and northwest. 34 A. W. McCoy: A short sketch of the paleogeography and historical geology of the Mid-Continent oil district and its importance to petroleum geology. Bull. Amer. Assoc. Petrol. Geologists, vol. 5, 1921, pp. 541-584. XIII—Buwuu. Grou. Soc. AM., Vou. 34, 1922 184 Cc. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES The whole relation of subsequent sedimentation was changed by the orogeny of late Pennsylvanian times and by another movement in eastern Colorado and New Mexico. This latter area of mountain-making is de- scribed by Lee in one of the papers of this symposium, under the name of “Ancestral Southern Rocky Mountains.” ‘To the east of the latter lay the Permian shallow-water seas of Texas, Oklahoma, and Kansas, laying down great sheets of clastics derived from the west, along with the most extensive deposits in North America of sodium chloride and gypsum. On the other hand, the Arbuckle and Massern mountains remained as land athwart the late Pennsylvanian and Permian seas, but the Wichitas were finally completely submerged by Permian sediments. In Nebraska, Kansas, and Texas, however, the Pennsylvanian seas continued unbroken into Permian time. From the previous statements we see that the Ouachita embayment and its positive borderland, Llanoria, are as striking a geologic element in the evolution of the North American continent as are the Appalachian geosyncline and its borderland, Appalachia. The only marked difference is the lesser areal extent and the less complete marine record of the south- ern elements. On the other hand, the positive crustal movements in both areas appear to be harmonious and of the same orogenic realm. DEVELOPMENT OF THE CORDILLERAN GEOSYNCLINE (See Maps, Figures 4 to 17) GENERAL DEVELOPMENT The longest and widest, and by far the oldest and longest-continuing seaway is the one long known as the Cordilleran geosyncline. During the Paleozoic it extended from the Arctic Ocean southward through what is now the mountainous region of western North America into north- western Mexico, a distance of 3,000 miles. In Canada the width of this seaway is usually several hundred miles, while in the United States it is many hundreds of miles wide and at times attains a breadth of more than 1,000 miles. The eastern shores of this vast geosyncline and its marine extensions are the Canadian shield and its southern prolongation, Siouia, while its oceanward borderland is Cascadia, to the west of which is the Pacific Ocean. With the close of the Devonian the Cordilleran seas begin to restrict and their eastern shores in the far north begin to move westward. This change is further accentuated in the late Pennsylvanian and Triassic, so that by the end of Jurassic time there had arisen, almost out of the very center and along the entire length of this geosyncline, the very extensive DEVELOPMENT OF THE CORDILLERAN: GEOSYNCLINE 185 Cordilleran Intermontane geanticline. In Cretaceous times, then, there lay on the western side of this geanticline the Pacific geosyncline, with a length of at least 2,500 miles, and on its eastern one the Rocky Mountain geosyncline, or Coloradoan sea, extending in the form of a sigmoid curve from Behring Straits into the Caribbean mediterranean, a distance of over 5,000 miles, EARLY CORDILLERAN GEOSYNCLINE (See Maps, Figures 4 to 12) Just when the Cordilleran geosyncline came into existence is not ‘known, but it is certain that its central part was present early in Proterozoic time, and seemingly with about the same position and extent as in the early Paleozoic (see map, figure 1). Its presence is clearly evidenced by the vast deposits of Proterozoic time in the Beltian series, extending certainly from Great Salt Lake into British Columbia to about 55 degrees north latitude. Furthermore, in the Grand Canyon area of Arizona other thick Proterozoic deposits are known, so that we may say that the Cordilleran geosyncline in Proterozoic time had a regional distribution similar to that which it had during the early Paleo- zoic. ‘These Proterozoic deposits, mainly sandstones and shales and with very little of limestones or igneous materials, vary in thickness from 15,000 to over 30,000 feet, and as their depth and coarseness increase westward, it is also clear that even then Cascadia was, as later on, the bounding western borderland. Probably the most extraordinary fact in our present studies is that of the conformable relations of the Pro- terozoic and Paleozoic strata. In other words, there was no markec orogeny in the Cordilleran geosyncline at the close of the Proterozoic as there clearly was in all the other marginal areas of North America. Can this tranquillity of the American Cordilleran region mean that the North Pacific Ocean was not a decidedly sinking region during the Proterozoic, and that this vast basin did not begin to become crustally unstable until late Jurassic time, when the evidence of vast mountain- making appears for the first time in many lands that bound the Pacific Ocean? As yet we know of only local orogeny in the Cordilleran region of North America during Proterozoic and Paleozoic time. Therefore one of the extraordinary phenomena in the geologic history of the Cor- dilleran region is the conformability of Proterozoic, Paleozoic, and even Mesozoic formations up to the close of the Jurassic. The thicknesses of the Paleozoic formations throughout the western part of the Cordilleran geosyncline vary between 10,000 and 23,000 feet, being apparently greatest in the southern half. The Cambrian, 186 Cc. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES Ozarkian, and early Ordovician deposits are very thick throughout the geosyncline, varying between 6,000 and 16,000 feet. It is the grandest known Cambrian sequence anywhere in the world, and our knowledge of it is almost wholly due to Walcott. The Middle and Upper Ordovi- cian and all of the Silurian may be absent or are poorly represented, apparently by not over 500 feet in thickness, in the medial length of the geosyncline, while the later Devonian is usually present, though never thicker than 1,000 feet. About middle Mississippian time a great change took place in the extreme northern portion of the trough, since the whole Mackenzie region was then warped above sealevel, and this area did not again have deposits until Jurassic time. Therefore it is only in the southern two-thirds of the Cordilleran geosyncline that the later Mississippian, Pennsylvanian, early Permian, and Triassic are present in thick deposits, varying in depth between 1,500 and 5,500 feet. In other words, we agreé with Ulrich that the Paleozoic sequence in the Cordilleran seas is far less complete than that of the Appalachian geosyncline, and that the latter area is best “fitted to fill the require- ments of a standard” for stratal correlations in America. These con- clusions therefore appear all the more strange when we take into con- sideration the fact that the Cordilleran seas, when present, were often more extensive than were those of the Appalachian trough. RISE OF THE ANCESTRAL ROCKY MOUNTAINS GEANTICLINE (See Maps, Figures 2 and 12) We must now make a little digression to explain the rising of a geanticline in the eastern portion of the Cordilleran geosyncline, one that is clearly described by Lee (see page 286) as the Ancestral Southern Rocky Mountains. All through the earlier Paleozoic the Cordilleran seas transgressed eastward on and at times across the neutral region Siouia. In the same way the Mississippian seas spread westward variably over parts of Siouia. These conditions continued until late in the Tennesseean. Then, apparently early in Pennsylvanian time, at least all of eastern Colorado and New Mexico, western Kansas, western Oklahoma, and northwestern ‘Texas was bowed up into the high Ancestral Rocky Mountains geanticline. To the west of this highland lay the Cordilleran seas of late Paleozoic time, while to the east of it the Mis- sissippian seas of late Pennsylvanian time and the following Red Beds Permian overlapped to the westward. In other words, the source of sediments for these seas was completely changed by this geanticline. Finally, we learn from Lee that the whole of this arch was eroded to sealevel by late Jurassic time, since the Logan sea, and more especially that of the Cretaceous, completely transgressed it. DEVELOPMENT OF THE CORDILLERAN GEOSYNCLINE 187 LATE CORDILLERAN GEOSYNOLINE (See Maps, Figures 12 to 17) We now return to a further consideration of the Cordilleran geosyn- cline, and more especially to its changes after Devonian time. It has been shown that this trough had a uniform development throughout the Proterozoic and early Paleozoic. For the first time crustal deformation set in late in the Devonian, but only locally in northern California (Shastan channel) ; and a little later, in the Mississippian, upwarping took place over a very wide region in the Mackenzie River area, com- pletely blotting out here the Cordilleran geosyncline. With these move- - ments we see Cascadia transgressed more definitely by the Shastan chan- nel and the Alexandrian embayment, and taking on northwest-southeast trends that bring about the further delimitation of its parts into the borderlands, California and Charlotte. In consequence the inland seas of Carboniferous times also took on northwest-southeast trends. This new alignment of lands and seas is seen even better in late Pennsyl- vanian time, but here the areal expanse of the seas is still very extensive and much like the conditions earlier in the Cordilleran geosyncline. RISE OF THE CORDILLERAN INTERMONTANE GEANTICLINE With the continued rising of the Ancestral Rocky Mountains, the Cordilleran sea of Middle and Upper Triassic time was pushed westward, blotting out gradually the whole of the medial portion of this old geosyncline. Finally, early in the Jurassic there began farther west the rising of the Cordilleran Intermontane geanticline, which during the Cretaceous separated two independently evolving geosynclines. This greater arch, however, was not completed until after the close of the Jurassic, for the Logan sea of early Upper Jurassic time was still in wide marine connection with both the North Pacific and the Arctic oceans. Finally, toward the close of the Jurassic, followed the Sierra Nevada orogeny—a time of marked mountain-making throughout the length of western North America, but chiefly in the area of the Cor- dilleran Intermontane geantichne. This further rising of the geanti- cline extended it unbroken as a marine barrier from Siberia into Central America and brought into existence two new and wholly distinct sequent geosynclines—sequent because of their formation out of the greater and older Cordilleran geosyncline—the Rocky Mountain one on the east and the Pacific trough to the west of this geanticline. This arched land exists today as the Northern Interior, Columbia, and Nevada-Sonoran high plateaus of Ransome.*° 35, L. Ransome: The Tertiary orogeny of the North American Cordillera and its problems. In “‘Problems of American geology,” 1915, pp. 287-376. 188 Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES PACIFIC SEQUENT GEOSYNCLINE (See Maps, Figures 12 to 17) Let us first consider the shorter and narrower Pacific geosyncline, but one with a far longer history than the eastern or Rocky Mountain trough. It extended from the Alexandrian archipelago of southeastern Alaska to the southern end of Lower California, and while its main history is of Mesozoic time, yet during the whole of the Cenozoic the Californian sea was a decidedly subsiding geosyncline. Actually there were, however, two more or less distinct Pacific geosynclines with different histories. To the northern one, restricted almost wholly to Canada and essentially of Mesozoic time, it is proposed to give the name of British Columbia geosyncline, while the southern one, of much longer endurance, has long been known as the California sea. All through the Paleozoic the Alexandrian embayment of south- eastern Alaska was in evidence, and its seas, beginning with the Silurian and continuing with interruptions up to the close of the Permian, laid down apparently not less than 12,000 feet of sediments, though the depth may be a great deal more (see maps, figures 7 to 17). With the late Pennsylvanian, however, this embayment became but the northern part of the British Columbia geosyncline, and the eastern shoreline of the northern part of the Cordilleran trough was moved far to the west. This northern geosyncline of late Paleozoic time continued unbroken into the Californian sea, which at this time still retained its former wide eastern spread. The British Columbia geosyncline, however, was not in typical development until Upper Triassic time, and was blotted out during the earlier Upper Cretaceous, long before the Rocky Mountain trough was folded into mountains. The Triassic deposits of the British Columbia geosyncline attain a maximum depth, on Vancouver Island, of 13,000 feet, but nine-tenths of this is volcanic extrusives. The Jurassic is well represented by from 3,000 to 8,000 feet of deposits. Of earlhest Cretaceous strata there are none, and the sea returned in late Lower Cretaceous times and continued unbroken into that of the Pierre, during which interval there were de- posited from about 4,000 to 15,000 feet of coarse clastics and lava flows. In other words, the whole of the trough subsided, from the Middle Penn- sylvanian to the close of the Cretaceous, something like 25,000 feet. Now let us consider the southern half of the Pacific sequent geosyn- cline, or, better, the Californian sea. The Shastan channel was clearly in evidence with the Middle Devonian, and the Cordilleran seas did not become narrowed until Middle Triassic time. Therefore it was in the Upper Triassic that the Californian geosyncline made its appearance. DEVELOPMENT OF THE CORDILLERAN GEOSYNCLINE -189 It extended from Oregon south to the end of Lower California. During Mesozoic time it subsided not less than 27,000 feet, and to this must be added the Paleozoic strata, amounting to something like 8,000 feet more. ‘Toward the close of the Cretaceous large parts of the trough -were folded, roughly in what is now the Great Valley of California and the Coast Ranges; then during the Cenozoic the trough continued to receive marine and fresh-water sediments that on the average will prob- ably exceed 30,000 feet in depth. The stratal history of Lower Cal- ifornia is too little known to go profitably into its detail except to say that it is best known since early Upper Cretaceous time. The orogeny of the late Cretaceous does not appear to have been of a very marked character, since in places the Mesozoic and Cenozoic deposits are conformable to one another. Orogeny was more pronounced at the close of the Oligocene, strongly so at the end of the Middle Miocene (Monterey), moderately at the close of the Miocene, and most pro- nounced of all at the close of the Pliocene. In the evidence recited we see that northeastern California subsided during the Paleozoic and up to the close of the Jurassic something like 22,000 feet, and following the rise of the Cordilleran Intermontane geanticline central California sank during late Mesozoic and all of Cenozoic time probably as much as 45,000 feet. ROCKY MOUNTAIN SEQUENT GEOSYNCOLINE (See Maps, Figures 14 to 17) We have seen that early in Lower Cretaceous time there came into full existence the Cordilleran Intermontane geanticline. ‘To the east of this long arch, that continued to rise throughout Cretaceous time, there gradually developed the Rocky Mountain geosyncline that in full development extended from Siberia into the Caribbean mediterranean. This vast subsiding realm is readily divisible by its structural features _ into three areas. In the north (1) is the Arctic-Mackenzie region, (2) south of the Liard River into northern New Mexico is the very wide Rocky Mountain or Dakotan sea, and (3) from southern New Mexico and Arizona south is the Mexican area. Let us take up first the Mexican geosynclune, since the marine trans- eression begins earliest here. Nearly all of Mexico was land throughout most of the Paleozoic, and the only parts frequently under water were the narrow southern Tehuantepec region and the greater Sonoran em- bayment across Sonora, Arizona, Chihuahua, New Mexico, and western Texas. As yet, it can not be said with certainty that Mexico has the characteristics of an ancient shield, and that it was a low land throughout 190 Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES Paleozoic time, though we may for the present assume this condition because of the relatively thin deposits of the Sonoran embayment. The Mexican geosyncline made its appearance in the north late in Pennsylvanian time, then in the south late in the Triassic, more definitely early in the Jurassic, and before the close of this period its waters had attained Texas. Then there was a retreat of the sea from the north, but early in the Lower Cretaceous a general transgression of the Mexican sea set in, that widened until it finally covered more than two-thirds of Mexico. It continued to spread northward into the United States, and early in the Upper Cretaceous (Benton) the Mexican waters united with the Dakotan sea, that since late Lower Cretaceous time (Blairmore) had been spreading southward. The maximum thickness of the Mesozoic deposits in Mexico may be as great as 20,000 feet. The Arctic coast of Alaska is too little known to determine whether there is here a geosyncline having a borderland facing the Arctic Ocean. The older Paleozoic formations have been found to be some thousands of feet thick, followed in the Cape Lisburne area by more than 5,000 feet of Lower Carboniferous. The Jurassic, wholly of continental strata, is 15,000 feet thick, followed by about 5,000 feet of Cretaceous. This region, for easier reference, may be known as Endicott sea. The stratal history of the Mackenzie Valley in its broader aspect has been made known during the past ten years, and it is now established that, beginning with the Lower Cambrian, there was no orogeny in this region until late Cretaceous time. Not even the late Jurassic rising of the Cordilleran Intermontane geanticline affected the area of the Mackenzie Valley or, for that matter, any of the region of the Rocky Mountain geosyncline. Here during Cambrian to late Devonian times the Cordilleran trough received no less than 13,000 feet of marine strata. Then the region was warped above sealevel, and there are no strata of any kind until late Jurassic time, when the overlaps of the British Columbia geosyncline toward the east attained the region of the Macken- zie Valley. The making of the Cordilleran Intermontane geanticline fol- lowed, but in this region the arch apparently was not a highland, since to the east of it the Cretaceous deposits do not exceed a few thousand feet in thickness. It was during the late Lower Cretaceous (Blairmore-Albian) that the Arctic Ocean began to spread south through the Rocky Mountain geosyn- cline, but these marine waters seemingly did not extend south of the Peace River of Alberta, though fresh-water coal-bearing strata of about this time (Kootenai) occur southward through Alberta into Montana. Then the seas retreated northward, or, better, their spreading appears DEVELOPMENT OF THE CORDILLERAN GEOSYNCLINE 191 to have been oscillatory during Lower Cretaceous time, just as were the Comanchian (Washita) seas spreading from Mexico northward to make the Dakotan sea. Finally, in early Upper Cretaceous (Benton) time, the Rocky Mountain geosyncline was at its height of flood, making the largest inland sea that ever lay upon the North American continent. It then extended continuously from the Arctic Ocean into the Caribbean mediterranean, and from British Columbia, Idaho, and Utah eastward into Manitoba, Minnesota, Iowa, Kansas, and eastern Texas. Along the western side of the trough from Wyoming north into Alberta, from 10,000 to 20,000 and locally even 25,000 feet of coarse clastics were laid down. ‘Toward the east all the formations thin away rapidly to a few thousand feet in depth. However, soon after the fullness of this great sea the northern end of the geosyncline began, in Niobrara time, accord- ing to Dowling,*® to warp above sealevel. The higher arching continued to spread southward during the remainder of Cretaceous time, causing the wide Coloradoan sea to change into a continually southwardly shrink- ing gulf, and the last of its marine waters (Cannonball) were blotted out just before Fort Union time.*‘ Fresh-water formations, however, © continued to accumulate for a time (Fort Union, Puerco, Torrejon), and finally, late in the Paleocene or, more exactly, just before Wasatch time, came the second and most marked time of late Cretaceous orogenies, transforming the Rocky Mountain geosyncline into the mighty Cordillera of western North America. ‘he folding and thrusting was away from the geanticline and toward the east. On the other hand, as the eastern mountains of the Pacific system appear to be folded and thrusted away from the Intermontane geanticline, we see in parts of the polygenetic Cordilleras of western North America another example of bilaterally symmetrical mountains. We must return once more to the sediments of the Rocky Mountain geosyncline to bring out the striking fact that in the area of greatest subsidence—that is, in Idaho, western Montana, southeastern British Columbia, and southwestern Alberta—there had been no orogeny from early Proterozoic time until the close of the Cretaceous. During this vast time there was laid down in this area about 20,000 feet of Mesozoic strata, resting conformably upon 26,000 feet of Paleozoic formations, and these in turn lie conformably upon about 30,000 feet of but little metamorphosed Proterozoic rocks. It is the longest accessible geological section known anywhere and attests the striking fact that the earth’s crust may subside at least 14 miles before it becomes folded into mountains. %D. B. Dowling: Summ. Rept., Geol. Survey Canada, 1921, 1922, pp. T9B-90B. aT. W. Stanton: The Cannonball marine member of the Lance formation. U. S. Geol. Survey, Prof. Paper 128, 1920. 192 C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES SONORAN EMBAYMENT (See Maps, Figures 1, 5 to 11) The Sonoran embayment was an east-west trending seaway in con- nection with the Cordilleran geosyncline during Paleozoic time. It appears to have come into being during the Proterozoic. There is, how- ever, no region of North America less known geologically than north- western Mexico, and therefore the history of this embayment can be given only in the light of the strata known in southern Arizona and New Mexico and southwestern Texas. There may, therefore, be in this area many more horizons than are now recognized. We have already given the Cambro-Ordovician history and pointed out that the thickness of these deposits may attain a maximum of 3,000 feet (page 182). The uppermost Ordovician and the Middle Silurian appear to be well represented by about 1,500 feet of sediments, mainly limestones. The Upper Devonian and the Lower Mississippian are also well represented by about 1,500 feet of clastics and lhmestones, while the thin Upper Mississippian is known only in southwestern Texas. In middle Penn- sylvanian time the western end of the Sonoran embayment was blotted out by mountain-making, and then the eastern part of the Cordilleran sea opened out southeastward across Chihuahua and Coahuila into the Gulf of Mexico. | Then the thickest stratal development in this trough appeared, in middle and late Pennsylvanian and earlier Permian times; these deposits in southwestern Texas may exceed 10,000 feet of clastics and limestones. It is by all means the best marine section of these times anywhere in North America. With the middle Permian, this earliest appearance of the Mexican geosyncline vanishes and the region remains dry land until the Lower Cretaceous, when the Comanchian seas of the Gulf of Mexico- spread westward across Chihuahua into eastern Sonora and northward across eastern New Mexico into Kansas. Of these Lower Cretaceous strata the thickness may not exceed 3,000 feet. All in all, it appears that no part of the Sonoran embayment sank in Paleozoic times over 20,000 feet, and it is more probable that the maximum thickness of de- posits in any one place is not over 15,000 feet. DEVELOPMENT OF THE FRANKLINIAN GEOSYNCLINE (See Maps, Figures 3, 5 to 13) We will now study the stratal history of the extreme northern end of North America. Explorers have been bringing scattering geologic knowl- edge out. of Arctic North America for nearly a century, but, due espe- DEVELOPMENT OF THE FRANKLIN GEOSYNCLINE 193 cially to the concentrated work of the Norwegians (Per Schei) and the Danes (Lauge Koch) during the past twenty-five years, we are now see- ing far more clearly the general stratigraphic sequence and the broader structural relations of this region. Our knowledge is best for Ellesmere- land and northernmost Greenland, where it appears that there is a maxi- mum of deposition exceeding 21,000 feet. The Arctic seas began to spread over the Archean formations in Upper Cambrian times, and thence until the close of the Triassic the sequence is about as complete in the Franklinian geosyncline as in any of the other American troughs. Upper Cambrian, Ozarkian, and basal Ordovician times are well represented by from 5,000 to 8,000 feet of more or less clastic strata, the rest of the Ordovician and Silurian by about 4,000 feet of limestones, the Devonian by 6,000 feet or more of mainly clastics, while the Carboniferous lime- stones and Triassic shales may considerably exceed 3,000 feet. The strata thicken and beconte coarser toward the north and northwest in the very areas of the most intense folding of the United States Mountains, first made known by Lieutenant Peary. These mountains have peaks up to 8,000 feet and are the northernmost range of the earth, extending from Cape Morris Jesup to Robeson Channel and across it into Grant, Grinnell, and Peary lands. The thinning out of the strata is toward the southeast across Greenland and southward through the Franklin Archi- pelago and the Northwest Territory of Canada, parts of the vast Cana- dian shield. It is interesting to note further that northern Ellesmereland (Grant Land) and Peary Land are margined by Archean rocks, and they are to be interpreted as remnants of the borderland that furnished most of the detritals for the Franklinian geosyncline. This old land may be known as Pearya, and how far it extended into the present Arctic Ocean is, of course, unknown. Since the depths of this ocean north of Greenland and the Franklin Archipelago are not nearly as great as farther north- ward, it may have had a breadth of many hundreds of miles. That we are dealing here with a borderland having along its inner side a geosyn- cline whose waters lapped upon the Canadian shield is attested by the position and trend of the United States Mountains and by the further fact that the folding and overthrusting, according to a personal conver- sation with W. Elmer Ekblaw, is away from the Arctic Ocean and toward the southeast. Koch* refers the making of the United States Mountains to the Cale-. *QVLauge Koch: Stratigraphy of northwest Greenland. Meddel. dansk. geol. Foren., vol. 5, no. 17, 1920, pp. 1-78. Preliminary report upon the geology of Peary Land,. Arctic Greenland. Amer. Jour. Sci. (5), vol. 5, 1923, pp. 189-199. 194 Cc. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES donian deformation of late Silurian time, but, since at least the Penn- sylvanian strata are involved in the folding, it is clear that the origin of these ranges can not be older than late Pennsylvanian time. On the other hand, the Triassic strata appear to be unfolded and may represent a transgression restricted to the southwestern and more open remainder of the Franklinian geosyncline. NATURE OF MEDITERRANEANS COMPARED WITH GEOSYNCLINES GENERAL DISCUSSION The American theory of geosynclines is widely accepted by the Euro- peans, but their typical area for this structure is the mountains of south- SIBERIAN ONTINENT PACIFIC CONTINENT FIGURE 18.—World Chart showing Geosynclines and hypothetic Continents during Mesozoic Time After Haug, 1909, from Ruedemann, 1922. ern Europe and the Roman Mediterranean, extending into Asia, the site of a former greater mediterranean (see figure 18). To this very extensive seaway of the geologic past, Suess many years ago gave the name Tethys. Since Tethys was the consort of Oceanus, we see in this linkage of the gods also the idea that mediterraneans have the characteristics of oceans. This is true of mediterraneans in nearly all of their physical aspects except as to size and shape, since their typical form is that of elongate MEDITERRANEANS COMPARED WITH GEOSYNCLINES 195: oceans that are much more completely hemmed in by continents. It is. true, however, that both types of marine areas are greatly depressed deep-- water basins situated between continents. (Geosynclines, in the American sense, on the other hand, are long and narrow shallow-water inland seas ‘lying wholly upon a continent (see map, figure 3). As the grandeur of European geology lies mainly in the mountains of the Mediterranean countries, their history and orogenies are well known, and it was but natural for the geologists of Europe to apply the term geosyncline to the area of the Tethyian deposits; all the more so since Dana, the author of the term, used it in several senses. He says:*° “That there were profound geosynclines over the oceanic basins during the: later Tertiary and early Quaternary is put beyond question by the fact of the great continental elevations of the same time. The Coral Island subsidence,. announced by Darwin in 1839, recognized such geosynclines; and they were long since set forth by Dana as the counterpart of the continental movements.” It is, therefore, but a natural conclusion for Pirsson to say*® that geo- synclines as well as geanticlines “may occur on the continents, as well as: on the ocean floor.” From these quotations we see that the term geosyncline has been al-- tered from the original sense of Hall to the wider one of Dana, and that it is now appled to all marine basins of long-continued sinking and stratal accumulation. This condition of things has become so thoroughly engrafted in the literature of geology that it is probably impossible to change it. We will therefore use the term geosyncline in the generic: sense, as extended by Dana, and apply it to all the greater long-continued down-flexured parts of the lithosphere. With this limitation, rifts and graben are excluded. | Of such crustal flexures, there are at least four categories. These are: as follows: MONOGEOSYNCLINES The true geosynclines as originally defined by Hall and Dana, which finally give rise to but one synclinorium, are exemplified by the Appa- lachian geosyncline. They are long and comparatively narrow, deeply subsiding, but always shallow-water, smaller, primary geosynclines, situ- ated within a continent along the inner side of borderlands. They should hereafter be known as monogeosynclines, because they are the simplest of geosynclines. 39 J. D. Dana: Manual of geology, 4th ed., 1895, pp. 936-937. 40 L. V. Pirsson: Text-book of Geology, Pt. I, Physical geology, 2d ed., 1920, p. 305. “196 C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES POLYGEOSYNCLINES These are the more or less wide and longer-enduring but shallow-water ‘primary geosynclines, which give rise to one or more parallel geanticlines and to two or more sequent geosynclines with shorter histories. In other words, they are primary and greater geosynclines within a continent and situated along the inner sides of borderlands, but evolving into two or ‘more sequent geosynclines separated by geanticlines. The typical ex- ample is the Cordilleran primary trough, out of which have arisen the Cordilleran Intermontane and Ancestral Rocky Mountains geanticlines and the subsiding Pacific and Rocky Mountain sequent geosynclines. They may be known as the polygeosynclines, the prefix suggesting that several geosynclines are combined. Another fine example is the Andean polygeosyncline. This great geo- syncline, in its size and complex history, reminds one much of the Cor- dilleran trough, and it was in the making throughout the Paleozoic and Mesozoic. To the west of it lay a wide borderland, first determined by Burckhardt*! for Jurassic time and fractured into the depths of the Pa- cific during the Cenozoic. This downfracturing was especially active during the Pleistocene and it was in keeping with the very marked up- faulting of the Andes, raising the late Cenozoic peneplain at least 10,000 feet into the Alta Plana of present Bolivia. To the east of the Andean polygeosynchne is the Brazilian shield, the nucleus or neutral area of South America, and over its western part occasionally spread in earlier Paleozoic time the waters of the western seas. As in North America. the thickest deposits are in the west nearest the borderland. It appears that the width and degree of geologic complexity in the structure of the geosynclines are dependent on the magnitude of the near- est ocean. In other words, the greater the ocean, the wider the trough. In eastern North America the comparatively narrow Appalachian monogeosyncline ceased to subside in the Pennsylvanian, and during the Permian the folded structure of the Appalachian polygenetic mountains was completed. Never again was this region subject to orogeny, and the width of the folded tract is about 450 miles. The region has, however, been arched several times since. The orogenic region of western North America is, on the other hand, not less than 1,100 miles wide—that is, from eastern Colorado to Cali- fornia—and in this area have originated, inside of the borderlands, three geosynclines and two geanticlines. We are therefore led to believe that 1C, Burckhardt: Beitrige zur Kenntniss der Jura- und Kreideformation der Cordillere. Paleontographica, vol. 50, 1900, pp. 1-144. MEDITERRANEANS COMPARED WITH GEOSYNCLINES 197 this very wide and long-enduring polygeosyncline is so because of its developmental relation with the vastness of the Pacific, the greatest of oceans. . ‘ MESOGHOSYNCLINES, OR MEDITERRANEANS - The mediterraneans are the areally smaller and decidedly elongate, but most mobile oceans, and are more completely bounded by continents than are the true oceans. They are characterized by abyssal waters, by ex- cessive mobility, and by very intricate histories, combining eventually several geanticlines and geosynclines. The Roman Mediterranean is the best known example, and, to distinguish this type from the other geosyn- clines, they may be known as mesogeosynclines (with reference to their position between continents) or simply as mediterraneans. In Europe the theory of geosynclines centers in the structure of Tethys and is set forth in the great work of Haug.** He defines them as follows: “The geosynclines, essentially mobile regions of the earth’s crust, are always situated between two continental masses or relatively stable regions. They constitute, before their filling with sediments, marine depressions of quite a considerable depth” (page 632). “It is evident that the folded mountain chains have in general become emergent geanticlines, and divide the primitive geosyncline into secondary ones. After the folding phase the whole is again depressed, the geanticlines are again covered by the sea, and the same phe- nomena are reproduced in the same order up to the emergent condition” (page 708). Again: “Most often the strata of the geosynclines belong to the bathyal type. American writers have always taken as a point of departure for their theories on mountain-making the fundamental idea that mountains are formed on [inside of] the border of oceans, and that the continents increase by the addi- tion of other chains, more and more recent. [The last part of this sentence is not an American idea.] Under this hypothesis, geosynclines take birth at the limit between continents and oceans, the sediments which accumulate there are exclusively littoral, and the zone of sinking, with the greatest thickness of strata, is separated from the ocean by a simple swelling.” * From these quotations we see that Haug’s theory of geosynclines is far from the American conception of the evolution of the continent of North America as described in this address. In the first place, the conti- nent was much larger in Proterozoic time than it is now, and paren- thetically it may be added that the writer holds most of the continents #”H. Haug: Les géosynclinaux et les aires continentales. Contribution 4 l'étude des transgressions et des regressions marines. Bull. Soc. Géol. de France, 3d ser., vol. 28, 1900, pp. 617-711. 8H. Haug: Traité de géologie, 1907, pp. 160, 166. 198 Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES to have been originally larger than they are now. Nor are the geosyn- clines “at the limit between continents and oceans”’—that is, they are not on the continental shelves. The monogeosynclines and polygeosynclines are situated hundreds of miles within the continents, inside of border- lands that are not mere “simple swellings.” We therefore see that mesogeosynclines are not situated upon a conti- nent, but that they, like the oceans, he between the continents. Also that their depth is oceanic in kind and their deposits range from clastics to the finest abyssal oozes. The entombed faunas are almost always normal marine ones, and even though they are often of shallow-water kinds, yet ereat thicknesses of almost unfossiliferous limestones and dolomites occur, suggesting for them abyssal waters. The mesogeosynclines have very long histories, and their structures show a far more complicated succession of orogenies and geanticlinal formations than do even the polygeosynclines; they are ever so much greater in area, depth of water, and in complicated structure than the monogeosynclines. On the other hand, it does not appear from what is known of the mesogeosynclines that they were ever completely drained of their waters, as was commonly the case with the monogeosynclines and polygeosynclines. In other words, the geosynclines within the continents reveal many more breaks in sedimentation than do the mesogeosynclines that lie between the continents. The depth of water in Tethys appears to have been very unlike in dif- ferent places. The Roman Mediterranean still has a length of about 2,200 miles and a greater width of over 1,000 miles. Its average depth is about 4,500 feet, while the western deep goes to 12,200 and the eastern one to 14,700 feet. Asiatic Tethys from Turkey to Burma is now moun- tain land, and its Paleozoic deposits indicate deeper waters than those of the Mesozoic, while the Cenozoic formations are essentially shallow-water clastics; none of the deposits, however, suggest abyssal depths, as do some of the formations of western Tethys. In late Paleozoic and Meso- zoic times the eastern Tethyian mesogeosyncline extended across southern Burma and Siam, through the Dutch East Indies, to New Guinea. This eastern extension of greater Tethys, along with its folded and decidedly overthrusted mountains, has been subsiding into the oceanic abyss since early Cretaceous time; here, too, the sediments with their oceanic faunas often also suggest very deep waters. These facts and inferences indicate that the mesogeosynclines are oceanic in character, duration, and geologic work accomplished, that they clearly are not comparable to monogeosynclines, and only in a general way are like polygeosynclines. ‘MEDITERRANEANS COMPARED WITH GEOSYNCLINES 199 Haug, seeing clearly that mesogeosynclines le between continents, and that the marine loading areas of today are situated upon the outer edges of the continents—the continental shelves—postulates these same places for the geosynclines of Mesozoic time. However, continental shelves have not the trough structure of geosynclines, and to get such troughs here during Mesozoic time, Haug postulates and maps continents, though with a great deal of doubt, over the entire areas of the present oceans! Accordingly, his theory calls for mesogeosynclines; but his making land of nearly all the oceans leads us to ask, What has become of all the marine water of Mesozoic time? Of course, he can give no answer. We can partially help him out of his difficulty by postulating (1) for the greatest geosynclines an inter-continental position—that is, the mesogeosynclines and oceans—and (2) an imtra-continental position for the polygeosyn- clines and monogeosynclines. At present the earth is without active geo- synclines in the sense of those of Mesozoic and Paleozoic times. The continental shelves are not geosynclines, since they have no outer border- lands. At the present time there appear to be no monogeosynclines in forma- tion, unless it be (1) the Baltic Sea and Gulf of Bothnia making their way into the White Sea, or (2) the Persian Gulf heading through Meso- potamia into the Mediterranean. The Red Sea is a rift sea, with depths down to 6,000 feet, and the Gulf of California, with a major depth of over 10,000 feet, appears to be another. Of polygeosynclines there also appear to be none now in formation. In regard to mesogeosynclines, the Mediterranean is clearly one and the Caribbean another. The island arcs off eastern Asia inclose the Sea of Okhotsk (depth to 12,000 feet), Japan Sea (10,500), Eastern Sea, and China Sea (16,100). The Yellow Sea appears to be nearly filled with sediments, since the greater part has depths less than 400 feet, but a small outer part goes down to over 7,700 feet. These recording basins can not be grouped into any of the mentioned types of geosynclines, since some of them have oceanic depths, but all are actually a part of the Asiatic continent. They are marginal geosynclines or parageosynclines (geosynclines beside a continent) and contrast with mesogeosynclines that lie between conti- nents. OCEANS The largest sinking fields are, of course, the oceans, with their down- fractured or downwarped parts of continents, their geanticlines, and their mountains of extrusion that are either single, clustered, or arranged in XIV—BULL. GEOL. Soc. AM., Vou. 34, 1922 200 Cc. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES lines. Oceans, however, are not geosynclines. Suess in 1909 wrote Ruedemann : “T do not believe in oceanic geosynclines. No existing ocean has a synclinal structure, except by superimposed sediments, and the Pacific troughs [deeps] are not synclinals.” CoNTINENTAL FOUNDERING RIFTS AND GRABEN Rifts, even when filled with marine waters, are not geosynclines. They are, Gregory says,** “formed by the subsidence of strips of the earth’s crust between parallel faults.” The Great Rift Valley is the grandest example. This series of fault-formed valleys is continuous from Pales- tine to south of the Zambesi of southern Africa, and branches of it extend from the Gulf of Aden westward to the central Congo. The Red Sea is one of its marine invaded parts, with depths down to 6,000 feet, but the rift has “a total downthrow of 11,000 feet.” The Great Basin country of the United States is another example, with a much wider area of downthrow, which is something like 4,000 feet in Utah. The rifting of eastern Africa is generally believed to be due to settling of an uplifted arch of epeirogenic extent. Krenkel*® has shown, however, that the rifts cut all the geologic structures, none of which give unmis- takable evidence of an extensive arch. He states that Africa is being squeezed between the southwardly moving mass of Asia and the north- wardly pushing mass of the Antarctic Ocean. In consequence, Africa is moving northwestward. On the other hand, the Indian Ocean resulted in the foundering of eastern Gondwanaland, or, better, Lemuria, that began in Cretaceous time. Because of all these interacting movements, the outer crustal portion of eastern Africa has been widened about 5 per cent, the compensation for this enlargement giving rise to rifting on a grand scale. ‘This increase in area and faulting through tension has gone on in compensation for the orogeny elsewhere. Therefore tafrogenesis (from the Greek for rifts or graben) is the counterpart of orogenesis, and East Africa is the type area for tafrogenic structures. Rifts also develop in mesogeosynclines, and one of the best examples is the Ethio- pian mediterranean of Neumayr. It began to develop as a marine trough, about Permian time, between Africa and Lemuria, and persisted as such “J. W. Gregory: The rift valleys and geology of East Africa. An account of the origin and history of the rift valleys of East Africa and their relation to the contem- porary earth-movements which transformed the geography of the world. London. 1921. * I. Krenkel: Die Bruchzonen Ostafrikas. Berlin, 1922. CONTINENTAL FOUNDERING 201 to about the close of the Cretaceous, when the trough and its eastern borderland were almost completely broken up and faulted into the depths of the Indian Ocean. Graben are also downfaulted areas, but of much smaller dimensions. They may develop on any part of a folded land. FOUNDERING OF BORDERLANDS The borderlands of North America are pictured in figures 2 and 3. These show that North America in Proterozoic time was 2,000,000 square miles larger than it is now, and that Appalachia in the Devonian extended not less than 250 miles beyond the present shoreline. Now the eastern part of this land is warped at least 5,000 feet into the depths of the Atlantic. On the other side of North America the outer parts of Cascadia have been warped and probably in the main faulted into the Pacific to depths of 14,000 feet. During the Paleozoic and the earlier half of Mesozoic time the w Se coast of South America appears to have extended at least several hundred miles beyond the present shoreline, and some of this old land remains along the coast of Chile. Off Peru the Andes borderland has gone into the abyss anywhere between 13,000 and 24,800 feet, and this seemingly since middle Pliocene times. While this foundering was going on, the peneplaned Andes were raised vertically not less than 10,000 feet, a dif- ferential movement between the elevated and depressed masses amounting to nearly 7 miles. FOUNDERINGS OF CONTINENTS It is now widely admitted that Madagascar, an island of 230,000 square miles area, was once a part of Africa, and yet today it is separated from the latter by Mozambique Channel, from 240 to 600 miles wide, with depths down to 11,800 feet. Madagascar is, however, only the southern end of far greater Lemuria, a land of Mesozoic and older times that ex- tended northeasterly, taking in all of peninsular India. Of this conti- nent, there is left Madagascar, India, and groups of islands (Seychelles, Comoro, etcetera), with oceanic depths between them varying from 13,650 to 17,380 feet. The greatest of all foundered continents, however, is the ancient lesa. zoic land named by Neumayr Sino-Australia, embracing southeastern China and Siam, Sumatra, Java, Borneo, Celebes, the Philippines, New Guinea, Australia, New Zealand, New Caledonia, the lesser Hebrides, the Solomons, Fijis, and Samoas. Great areas of Sino-Australia have gone into depths variable between 10,000 and 13,000 feet and in places to over 202 C. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES 17,000 feet. The foundered areas are parts or the whole of mesogeosyn- clines and synclinoria and of geanticlines and anticlinoria. Abendanon has renamed Sino-Australia Aeguinoctia. The history of this foundering is still largely unknown. It probably began in the later Paleozoic, was most active in the later Mesozoic when Australia was separated from Asia, and these negative and positive move- ments have continued through Cenozoic time into the present. In most places along the margins of the continents facing the Pacific we note these great founderings, and the largest of all in the South Pacific. The chief area of crustal subsidence is, of course, in the water hemisphere, and it may well be that the united pull of the subsiding Antarctic and South Pacific oceans was the cause for the breaking up of Sino-Australia. The inbreaking of the Indian Ocean at the expense of Lemuria and ~ greater Australia was probably also in sympathetic connection with this negative movement of the Antarctic Ocean. In the Atlantic Ocean there is nothing comparable to this foundering of the Pacific. The relations are rather with the type of foundering in the Indian Ocean. Western Gondwanaland, uniting Africa to Brazil, was not in existence after Lower Cretaceous times, though there is much marine faunal evidence back of the latest Jurassic down to the Silurian, proving the existence of a land across the equatorial Atlantic. The foun- dering in the Atlantic began about the same time as that in the Indian, and all of it appears to have been in sympathetic connection with the vast subsidence in the water hemisphere. SUMMATION AND CONCLUSIONS My paleogeographic studies have confirmed the well-known fact that the vast medial region of the North American continent, while slightly positive, is in reality neutral in regard to sealevel. It is the “nucleus,” or “Kratogen,” of the continent, taking in the greater part of eastern Canada and most of Greenland (see map, figure 3). This very ancient land, in its rocks and structure, is seemingly in the main of Archeozoic making, but during much of Proterozoic time was still undergoing oro- geny. Since the late Ordovician the neutral region has been a lowland. The great neutral area of Canada is continued southwestward across the region known as Siouia into greater Mexico. It can therefore be definitely stated that Siouia and especially the Canadian shield have ever since the Cambrian furnished but little clastic sediment to the seas. Western Mexico and Siouia, on the other hand, were during the Mesozoic highlands furnishing sediments in great volume to the adjacent seas. SUMMATION AND CONCLUSIONS 203 Walcott long ago pointed out that the North American continent is very old, that it was not only outlined in late Proterozoic time, but that it was larger then than it is now. We now see that this continent had its present configuration even early in Proterozoic time, when it appears to _ have been 2,000,000 square miles larger than it is to-day. While the neutral area is wholly devoid of post-Proterozoic geosyn- clines, yet it was four times in the early Paleozoic widely covered by inde- pendent Arctic floods (see maps, figures 6 and 7). These spread southward across the nucleus into southern Canada, where their waters united with seas coming north through the Mississippi Valley. The first one was of middle Ordovician (Black River-Trenton), and the second of late Ordovician (Richmondian) time. The other two were of the early and middle Silurian (Alexandrian and Niagaran). In the north the combined depth of their marine sediments, largely limestones, may attain to 3,000 feet, while in southern Canada they appear to be measured by a few hundred feet. These floods, in continuation with the Franklinian trough, had nothing to do with those of the Cordilleran geosyncline, and their waters may or may not have been in communication with that trough. : Now let us consider the borderlands (see map, figure 3). The north- eastern portion of North America was margined by Acadia, of which there remains more visible than of any of the other borderlands. It was a marked diastrophic region from early Cambrian time to the close of the Pennsylvanian, though its marine history is practically pre-Carbon- iferous. ‘To the south of it lay Appalachia, which seemingly continued unbroken into greater Anttila. Appalachia was in periodic crustal unrest throughout the Paleozoic, and attained its maximum compression during the Permian. Shortly afterward, in the Triassic, this borderland began to fracture and to develop a block mountain structure, and the greater eastern part of it went under the Atlantic during middle Meso- zoic time. With its foundering, southern Antillia began to develop a marine history, and with the close of the Mesozoic and ever since, this southern borderland has been in the throes of crustal unrest. The Arctic side of North America was margined by the borderland Pearya. It was in existence as a highland certainly in Upper Cambrian time, and again in the late Devonian. Just when its orogenic history ceased is not yet clear, but seemingly during the Permian. The whole of western North America south of Alaska was margined by greater Cascadia. It was present in early Proterozoic time as a high- land, and again during the Cambrian. It was folded, locally, in northern California, during the Middle Devonian. In the Pennsylvanian or earlier 204 Cc. SCHUCHERT—THE NORTIL AMERICAN GEOSYNCLINES it divided into two northwesterly-southeasterly trending lands, a northern mass, the Charlotte borderland, which endured, though greatly reduced in area, into early Cenozoic time, and a southern one, the Californian borderland, which suffered marked orogeny throughout Mesozoic and Cenozoic times. At present, much of Cascadia is faulted into the great: depths of the Pacific. We have now recounted the most positive and the least positive areas of the North American continent, and next we must bring together a brief statement as to the various geanticlines (see map, figure 2). The oldest of these is the New Brunswick geanticline, dividing Acadia into two geosynchinals. This periodically rising axis had its origin at the close of the Proterozoic, and late in Devonian time it became so positive and so beset with active volcanoes as to blot out the seas on either side of it. Even though the earhest Carboniferous seas partially reentered between these mountains and formed the Northumberland embayment, yet this orogenic province continued positive till the close of Pennsyl- vanian time. | The next geanticline to appear arose out of the medial area of the greater Mississippian sea and divided it into two basins after early Silurian times. This was the well known Cincinnati geanticline. It was at no time during the later Paleozoic a very positive axis of uplift. During the later Pennsylvanian, there was much orogeny throughout the borderlands of eastern North America, and to a far more limited ex- tent in Texas and Oklahoma. In keeping with this mountain-making, the western area of neutral Siouia also began to rise vertically. This is the Ancestral Rocky Mountains geanticline, whose rising finally com- pletely blotted out in the area of Siouia the later Paleozoic seas. The geanticline was, however, reduced to sealevel before the Upper Jurassic, since the seas of this time and those of the Cretaceous again completely transgressed all of it. This old structure was reelevated by the Laramide orogeny and by the epeirogeny of late Cenozoic times. The most interesting of all the positive areas is the well known Cor- dilleran Intermontane geanticline (see maps, figures 2 and 16). This made its appearance through warping late in the Triassic as a low arch throughout the States of Arizona, Nevada, Utah, and Idaho, and then in the earlier Jurassic the arching was continued northward into British Columbia. It was completed by the Nevadan orogeny of late Jurassic time, which established it during the Cretaceous throughout the extent of North America. It was a geanticline of the first order, and was a vigorously rising mass during the Cretaceous. During its growth it blotted out much of the Paleozoic Cordilleran seas, and along its easterm SUMMATION AND CONCLUSIONS 205 side throughout the whole extent of the geanticline, from Siberia to the Caribbean, there developed the vast Rocky Mountain geosyncline. Struc- turally, it remade the western portion of the continent into a bilateral system of mountains, the mighty Cordillera of North America. We will next consider the geosynclines (see map, figure 3). It was between the great medial or neutral region and the much smaller border- lands that three of the four primary geosynclines were developed, namely, the small Arctic Franklinian trough and the better known Appalachian and Cordilleran geosynclines. Their greatest subsidence was toward the borderlands. Out of the Cordilleran primary geosyncline came the Pa- cific and Rocky Mountain sequent geosynclines (see map, figure 16). The small Acadian primary geosyncline, on the other hand, lies between the borderland Novascotica and the New Brunswick geanticline (see map. figure 3). The Cordilleran geosyncline is the oldest and has had the greatest amount of crustal evolution. A very small western part of it is still seen as a marine waterway in the Great Valley of California. This long- enduring geosyncline had its origin early in the Proterozoic, and during this era its maximum subsidence appears to have been about 30,000 feet. Curiously, no orogeny developed within the geosyncline at the close of the Proterozoic, but its borderland Cascadia was then reelevated into a highland, since the following Cambrian sedimentation alone was as much as 15,000 feet. Then there was no striking crustal change until early in Pennsylvanian time, when the Mackenzie shoreline was warped some hundreds of miles to the west, and the geosyncline consequently took on a northwest-southeast trend. We have seen that the Ancestral Rocky Mountains geanticline during Permian and Triassic times also pushed the eastern shoreline of this geosyncline something like 600 miles to the west. After the middle Triassic, the trough was greatly restricted, and with the subsequent rising of the Cordilleran geanticline, this great trough early in the Lower Cretaceous became the comparatively narrow sequent Pacific geosyncline. On the other hand, the rising of this geanticline is evidenced in the trough by marked volcanic activity, beginning in the late Pennsylvanian and attaining its climax in early and middle Triassic times. With the maximal rising of the geanticline late in the Jurassic, its area was to a large extent invaded by vast bathyliths and by renewed volcanic activity, the extrusive materials being also present in consider- able volume in the Lower Cretaceous strata of the Pacific geosyncline. Then toward the close of the Cretaceous, the British Columbia part of the Pacific geosyncline became land. The Californian trough, however, 206 C. SCHUCHERT—_THE NORTH AMERICAN GEOSYNCLINES continued as a marine area, although greatly restricted, not only through- out the Mesozoic, but the Cenozoic as well. With the rising of the Cordilleran Intermontane geanticline, there came into existence the eastern sequent and short-lived but very mobile Rocky Mountain geosyncline. ‘This subsidence appeared first in Mexico, beginning possibly early in the Permian and certainly in the late Triassic, and spread northward into Kansas,by the close of Lower Cretaceous time, when the Mackenzie end of the trough also had marine waters as far south as central Alberta. Then early in the Upper Cretaceous the whole of the geosyncline was one vast inland sea. The western geanticline again began to rise late in the Cretaceous, and apparently the whole of the arch from southern Mexico north into Alberta was then studded with active volca- noes. With this further rising of the arch, the Rocky Mountain seas were converted into land during the close of the Cretaceous. The present high altitude of the Cordillera, however, came with the vast epeirogeny that began in the middle Miocene and was completed toward the close of the Pliocene. The Appalachian geosyncline made its reappearance south of Virginia in earliest Cambrian time, but long before the close of the Lower Cam- brian it was in clear evidence from Alabama to Labrador. This is the type geosyncline (see map, figure 4). The northern half, or the Saint Lawrence trough, was blotted out by the orogeny of late Devonian time, and the whole of the Appalachian geosyncline was converted into moun- tains during the Permian. Last of the southern half of this geosyncline was the borderland Appalachia. Southeast of the Saint Lawrence trough and the New Brunswick geanticline was the Acadian geosyncline, and both troughs were elevated above sealevel by the Devonian orogeny (see maps, figures 7 and 9). Therefore we may say that the northern Appa- lachian system of mountains are bilaterally symmetrical structures, while the southern Appalachians, even though they are polygenetic mountains, are wholly a one-sided system folded and thrusted away from the Atlantic Ocean. To the northwest of Greenland is the Franklinian geosyncline, bounded on its Arctic side by the borderland Pearya, while its deposits thinned inland across the Canadian shield (see maps, figures 3 and 5). The presence of this geosyncline is clearly evidenced in late Cambrian time, and we suspect that it came into existence with the diastrophism of the late Proterozoic. During the Paleozoic, the Franklinian trough subsided something like 20,000 feet, and appears to have been blotted out by the orogeny of Permian times. SUMMATION AND CONCLUSIONS 207 Of embayments, there are four. (1) With the vanishing of the Saint Lawrence and Acadian troughs in Devonian time, there appeared in greater Acadia the Northumberland embayment, extending across the Maritime Provinces of Canada and Newfoundland (see maps, figures 10 and 11). It endured during the Mississippian and Pennsylvanian periods, the subsidence nowhere exceeding 18,000 feet. The embayment ceased with the Permian orogeny. (2) Chiefly in Arkansas and Oklahoma, from Upper Cambrian to Middle Pennsylvanian time there was developing the Ouachita embay- ment, an east-west trough connecting more or less directly with the Appa- lachian geosyncline (see maps, figures 8 and 6). It subsided markedly during its earliest existence but more especially during the Pennsylva- nian, since in Arkansas the maximum of depression appears to have been 35,000 feet. The trough failed as such with the Pennsylvanian orogeny. (3) Another west-east trough was the Sonoran embayment of north- western Mexico, which was more or less closely connected with the Cor- dilleran geosyncline (see maps, figures 3 and 6). It reappeared in the Upper Cambrian and endured into the Pennsylvanian, during which time the trough sank something like 15,000 feet. (4) The fourth of these basins was the Alexandrian embayment of southeastern Alaska, which finally merged with the Pacific geosyncline during the Pennsylvanian (see map, figure 3). It came into being at least as early as the Lower Ordovician, and during its existence the basin sank not less than 12,000 feet. It does not follow that when the geosynclines are in flood the neutral » areas are at the same time more or less under water. Frequently the floodings are restricted to the geosyncline, and at other times the Arctic floods cover essentially the neutral areas of the continents. In the same way, the Mississippian seas west of the Cincinnati geanticline may be in evidence when the Appalachian geosyncline is dry. It appears from the irregularity of the continental floodings that their presence is primarily due to crustal movements, but it does not at all follow that all are so brought about. The widespread and more or less cosmopolitan faunas of the Upper Cambrian, Middle Ordovician, Silu- rian, Devonian, and late Cretaceous appear to bear out Suess’ hypothesis of eustatic (=world wide) higher marine levels, when the continents are base-leveled and the oceans most filled with sediments, causing them to spill widely over the lands. Clearly, every grain of sand displaces just as much water. As to the time of origin of the primary geosynclines, we may say that all arose in the Proterozoic (see map, figure 1), and that out of the Cor- 208 c.SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES dilleran one there developed in Mesozoic time two sequent geosynclines (see map, figure 16). The amount of sediment in any of these troughs appears to have nothing to do with the time when they were folded into synclinoria. In places there may be even less than 10,000 feet of sedi- ments, on the average the amount of subsidence is between 15,000 and 35,000 feet, while in the mid-length and width of the combined Cordil- leran-Rocky Mountain geosynclines there was about 76,000 feet, or about 14 miles depth, of strata before the troughs evolved into synclinorial mountains. Nor has the length of geologic time anything to do with the vanishing of the geosynchnes. Both the Saint Lawrence and the Acadian troughs endured only from early Cambrian time to the close of the De- vyonian ; the southern Appalachian one was in formation from the early Cambrian into the Pennsylvanian; while vast stretches of the Cordilleran geosyncline did not foid from early Proterozoic time until the close of the Cretaceous, even though other parts of the trough rose into a very long and high geanticline during the middle Mesozoic. In all of this, we appear to see that the balancing of masses under the law of isostasy con- tinues until some other force changes the relations of things deep down within the lithosphere. ~ So far as North America is concerned, we see that no primary geosyn- clines have come into existence after the Cambrian, and that the larger ones were clearly established either late or early in the Proterozoic. Se- quent geosynclines, of as great importance as any (Rocky Mountain), along with vast geanticlines (Cordilleran Intermontane), originated in Mesozoic time, but their evolution was out of a very wide and primary geosyncline (Cordilleran). We therefore conclude that in North America. no new deeply subsiding areas have originated since the early Proterozoic. It may be that the present highly elevated condition of the Cordilleran Intermontane geanticline will subside some thousands of feet. Should this happen, it appears probable that an inland sea will form, extending the Gulf of Lower California into the Great Basin country. It will be, however, a rift sea lke the present Red Sea, formed through the in- breaking of the Cordilleran Intermontane geanticline, and not a new geosyncline. The narrower and shorter-lived geosynclines (== monogeosynclines) , seemingly conditioned by the smaller Atlantic and Arctic oceans, are in striking contrast to the far wider, longer-enduring, and immensely more diastrophically active geosynclines (= polygeosynclines) conditioned by the Pacific. We therefore ask, Has the vastness of the negative areas, the oceans, any direct and sympathetic action upon the sides of the positive continents? It would seem so. If this surmise is admitted, we must SUMMATION AND CONCLUSIONS 209 next ask the even more significant question, Why is it that western North America, in direct contact with the greatest ocean, exhibits but little orogeny until Jurassic time? We have seen that in eastern North Amer- ica, mountain-making was very active in late Devonian and again in Permian times; in Hurope at the close of the Silurian and several times during the Carboniferous. Do these facts, then, mean that the North Atlantic (= Poseidon) was an actively sinking ocean during the Paleo-. zoic, while the North Pacific was not a markedly subsiding area until early Mesozoic time? In further elaboration of these surmises, we note the greater volume of the sediments of the Appalachian, Acadian, and Franklinian geosynclines,, when contrasted for each period with those of the Cordilleran trough, which shows that the borderland Cascadia was less often reelevated than were the eastern borderlands Appalachia and Acadia. On the other hand,. in western North America, from Alberta south to Nevada, the greater part of the Ordovician and most of the Silurian are poorly represented by sediments, again showing that the Atlantic was diastrophically active: earlier than the Pacific. We may therefore speak of Atlantic and Pacific types of geosynchnes, since the same relations of parts are also true for South America. We must also ask ourselves, Why are there periodically rising border- lands with geosynclines along their inner sides? They appear to be the compensating areas of subcrustal flowage between the subsiding oceans and the unmoved or horst-like neutral areas or ““Kratogens” of the posi- tive continents. We will now consider the mesogeosynclines. It has been shown that all of the geosynclines of North America form on the inner sides of bor- derlands which are but the diastrophically active margins of the conti- nent. Furthermore, that geosynchnes are destined to evolve into moun-- tains. This is the American theory of geosynclines, and it is in direct opposition to the views of Huropean geologists, especially as formulated by Haug in 1900. The fundamental difference between the two theories: is that Haug places the geosynclines on the outer sides of the continents: in the areas of the continental shelves (figure 18). Huis studies center in the history of Tethys, the greater Mediterranean, once extending from the Atlantic to the Pacific. This is a very deep and vast basin of the oceanic type, situated, however, between close-lying continents. Tethys. was not, therefore, a geosyncline in the American sense, but a mediter- ranean or mesogeosyncline. To extend the meaning of the term geosyncline to all subsiding areas of sedimentary accumulation, to mediterranean and even to oceanic 210 C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES basins, as was done, it is true, for the first time by Dana, is to befog the brilliant idea of James Hall. Our understanding of geosynclines (both monogeosynclines and polygeosynclines) is that they are variably long and variably wide, very mobile, sinking areas that always originate within a continent; they are more or less long in geologic development, and receive great quantities of sediments derived in the main from the border- lands. The more rapidly sinking side of a geosyncline is adjacent to the inner side of a borderland, while the subsidence of the trough becomes less and less toward the neutral area of the continent. Finally, when orogenic forces have converted the geosyncline into synclinorial moun- tains, these either are the inner portion of the anticlinorial borderlands, or they occur on one or both sides of geanticlines. Mediterraneans are vastly greater fields of diastrophism, with the long- est and most intricate of geologic histories. Of ancient Tethys, the west- ern end still persists as the Roman Mediterranean, with depths down to 14,700 feet. Contrast these ocean-like basins with the shallow-water geosynclines, whose average depth is several hundred feet, and it becomes plain that the two types of marine waters can not be grouped together under one term. We have seen that all the geosynclines of North America have become dry land and mountainous. Into what are the mediterraneans evolving? We know that Tethys, formerly extending from Asia Minor to Burma, has been converted during the Cenozoic into dry mountainous land across 5,000 miles. Seemingly the whole of the Roman Mediterranean is des- tined to the same end, but eastern Tethys throughout the length of the Dutch East Indies is in the main foundering with its mountains perma- nently into the oceanic depths. The American mediterranean is to a lesser extent doing the same, since Antillia is breaking down into the Caribbean and the Atlantic. It appears that once a region is folded through lateral pressure, it rarely redevelops a geosyncline. This is most easily seen in the Atlantic type of troughs, since neither the Appalachian, Acadian, or Franklinian geosyncline has gone through even a partial second cycle of geosynclinal formation. On the other hand, the “Kratogens,”’ once the area of the most ancient geosynclines, may, after they are peneplained, be widely flooded by epeiric seas. This was the case with the Canadian shield, and the roots of the Paleozoic Alps of Europe have been widely transgressed by Mesozoic seas. ‘These floods are, however, not those of geosynclines. Nor do geanticlines or borderlands develop geosynclines. Therefore it may be assumed that a region once folded and made positive, becomes stiff and resistant, and that, as a rule, it will remain so throughout time. SUMMATION AND CONCLUSIONS Taek On the other hand, the borderlands and Sino-Australia have foundered - more or less into the oceans. In fact, even the Archeozoic and Protero- zoic synclinoria of the Canadian shield or kratogen have not undergone a second cycle of localized subsidence. However, a region once made positive through orogeny will subsequently be arched from time to time, and the aggregate of these epeirogenic uplifts may attain several thousand feet, as in the Appalachians (2,000) or the Rocky Mountains (7,000), or 10,000 feet as in the normally faulted rising masses of the Andes. We have also seen that out of the Cordilleran geosyncline there arose the Intermontane geanticline, while the sequent geosynclines on either side of it are the folded parts of the former greater trough. Diastrophism is mainly due to earth shrinkage. My paleogeographic ~ studies appear to make it clear that there are at least five sets of inter- actions bringing on the marine floods over the continent and the making of mountains. Three of these are in consequence of earth shrinkage, and one is due to crustal or isostatic adjustment. All of them are reflected in the marine transgressions and emergences. The sealevel is, in addi- tion, altered by the filling of the seas and oceans with the debris of the lands, by the subtraction of oceanic water and the piling of it upon the lands during glacial times, by the growth of mountains of extrusion, and by the movements within the oceanic basins themselves. It is not easy for stratigraphers to evaluate properly the significance of these oceanic alterations in their relations to continental floodings, and we may eventually come to see that their importance is far greater than is now believed. Taking Le Conte’s views of 1897 and modernizing them, we hold that of crustal movements there are four categories, as follows: (1) The most primitive, extensive, and longest-enduring progressive movements are those of (a) negative or downward direction, resulting in the oceanic depressions with the heavier kinds of rocks; and (6) positive or upward direction, giving rise to the continental platforms of lighter materials. (2) The comparatively quick orogenic progressive movements in one general direction due to crustal lateral thrusting. They give rise in the stratosphere (or tectonosphere, Sonder 1922) to the folded mountains (orogeny), and in compensating areas to stretching and rifting (tafro- geny). Harth shrinkage is concentrated in the main upon the geosyn- clinal areas, the lines of greatest weakness in the crust. (3) The slowly forming epeirogenic or more or less wide and high arching or vertical movements of an oscillating character, now upward and now downward. LEpeirogenesis predicates eventual orogenesis. PA Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES (4) The isostatic oscillatory movements in compensation for transfer ‘of load from one place to another; areas of sedimentation tend to sink, and eroding ones rise. Isostasy is an important cause of crustal move- ment, but is of secondary import to those produced by earth shrinkage. If we agree with T. C. Chamberlin that the earth since its growth out of planetesimals born of the sun has shrunk 570 miles radially, we see here the primal causation for the wonderful cyclic reelevation of the lands and sinking of the oceans, and much of the consequent periodic changes in climate. That the earth, under any theory of earth origin, is a shrinking mass, is shown mainly by the periodic folding of the lithosphere into mountain ranges, and by the subsidence of the oceanic areas. The crustal shorten- ing is further evidenced in the long-continued recurring times of epel- rogenic warping movements that culminate in the quicker orogenic ones. ‘This crustal shortening, due to radial shrinking, follows upon the loss of interior heat, magmatic alteration, and extrusion of lavas, ashes, water, and gases, and mainly through molecular rearrangement of the centro- sphere engendered by the continuous attraction pressure. With Kober, we therefore say that “shrinking of the earth is no longer hypothesis nor theory, on the contrary it is knowledge built on ascertained facts.” This periodicity, moreover, leads to the most extraordinary result of all, namely, to times of quickened organic evolution and the pulsing of hfe, to the peopling of the lands by the denizens of the oceans, an evolu- tion that somewhere and somehow has tended to make it possible for the alow of the seas to feed on the air and to clothe the land with verdure; the latter in turn yields food for the animals forced to emerge from the realm of Neptune, and thus life progresses dominantly upward until it results in reasoning man, the controlling organism of the Psychozoic era. My labor of love is now finished. I have told you in the main of the localized geosynclines and the oceanic floodings of the continent. In the following papers of this Symposium you will learn more of how geosyn- ‘clines are transformed into synclinorial mountain systems, or how vast expanses of inland seas become transformed into glorious mountains, areas scenically grand, geologically most difficult, and structurally highly interesting and significant. From studies in depression I turn you over to studies in uplift. ILLUSTRATIONS Daley Figure 1.—Geosynclines (dotted), Lands (white), and Oceans or Mediterra- neans (ruled) during late Proterozoic Time Black marks the known outcrops of Animikian, Keweenawan, Beltian, etcetera. The Cordilleran trough may have opened into the Arctic Ocean. FIGuRE 2.—North America in early Proterozoic Time Dotted spaces indicate the lands since foundered into the oceans. The posi- tions of four geanticlines of later eras are also shown. ILLUSTRATIONS AS: Ficure 3.—Borderlands (white), Geosynclines and Embayments (dotted), and neutral Areas (the great central Region between Geosynclines) of Paleozoic Time A= Alexandrian embayment. XV—BULL. GEOL. Soc. AM., VoL. 34, 1922 GEOSYNCLINES AMERICAN NORTH SCHUCHERT—THE ce ide) I Cambrian Time FIGURE 4.—Geosynclines of late Lower ILLUSTRATIONS De FIcurRE 5.—Geosynclines and their Extensions of Upper Cambrian and Cana- dian Time Intensity of shading indicates areas of greatest subsidence. 918 C. SCHUCHERT—THE NORTH AMERICAN Ficure 6.—Geosynclines and Embayments (dotted) and Arctic Sea (ruled) of Ordovician Time Intensity of shading indicates areas of greatest subsidence. ILLUSTRATIONS 219 PSR Se a ‘ST ee Gn z= TES ee a Tf GS Oe ees a SE NS FIGURE 7.—Geosynclines and Embayments (dotted) and Arctic Sea (ruled) of Silurian Time Intensity of shading indicates areas of greatest subsidence. 22.0 C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES Ficure 8.—Geosynclines, Embayments, and their Extensions during Devonian Time Intensity of shading indicates areas of greatest subsidence. ILLUSTRATIONS pal Vicure 9.—Cordilleran Geosyncline and Mississippian Sea of early Mississip- pian Time Shading indicates areas of greatest subsidence. 222 C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES Figure 10.—Seas and Embayments of late Mississippian Time Shading indicates areas of greatest subsidence. ILLUSTRATIONS FicureE 11.—Seas and Coal Swamps of early Pennsylwanian Time Shading indicates areas of greatest subsidence. Zoe C. SCHUCHERT—-THE NORTH AMERICAN GEOSYNCLINES FicurE 12.—Cordilleran, Mexican, and Franklinian Geosynclines; Mississip- pian Sea and Coal Swamps of late Pennsylvanian Time Shading indicates areas of greatest subsidence. ILLUSTRATIONS 925 Ficure 13.—Pacific Geosyncline, Arctic and Mexican Seas of late Triassic Time Areas of fresh-water red deposits in east and southwest. Shading indicates areas of greatest subsidence. WN bo SS C. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES Figure 14.—Pacific and Mexican Geosynclines and Logan Sea of early Upper Jurassic Time Shading indicates areas of greatest subsidence. ILLUSTRATIONS pal FIGURE 15. Californian, British Columbian, and Mexican Geosynclines of Middle Cretaceous (Albian) Time Sea over Florida. Shading indicates areas of greatest subsidence. 228 Cc. SCHUCHERT—THE NORTH AMERICAN GEOSYNCLINES i FIGURE 16.—Great Rocky Mountain and narrow Pacific Geosynclines and Gulf of Mexico Overlap of early Upper Cretaceous Time ILLUSTRATIONS me DIO SE REIE (Sse EN eG FIcurRE 17.—Great Rocky Mountain and narrow Pacific Geosynclines and Gulf of Mexico Overlap of late Upper Cretaceous (Pierre) Time Shading indicates areas of greatest subsidence. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 231-242 JUNE 30, 1923 KOBER’S THEORY OF OROGENY? BY CHESTER R. LONGWELL (Presented before the Society December 28, 1922) CONTENTS Page PTA 20h INNES LUCOPYo. <.. . 2 22a. eset elec eee pie ends dened B31 nr ee MIE TIC COE SUCSS 0)... lec ais ois ohlalee uo. Soe Oe eee abs de da es 2282 Comparison of views of Suess and Kober on the Mediterranean mountain SOUS RETR Soe 2 St I SS eR euatacreristics Of the Mediterranean ranges............05e-seceseese ee 200 Comparison of the Mediterranean orogen with other mountain systems.. 236 anne MME ATUL Cefn red ee a Ses eins PEs wan see see's wcaaeecéees 200 BRIEF OUTLINE OF KoBErR’s THEORY Professor Kober has attempted to fit all parts of the earth’s crust into a broad structural scheme, recognizing major units of two kinds: great plates or shields, continental in size, which behave as essentially rigid masses; and between them sinuous, comparatively narrow zones, which are relatively weak or labile and in which the effects of deformation are concentrated. These orogenetic zones are marked first by geosynclines, later by great systems of folded mountains. ‘Their positions, as well as the outlines of the plates, have changed somewhat through geologic time. Thus we find within some of the present rigid masses structure lines that mark the sites of mountain zones in the pre-Cambrian or the early Paleozoic. These were belts of weakness which have been healed or welded with the passage of time, while new labile zones have come into existence elsewhere. Therefore details in the structural aspect of the crust have varied, but there has been continued repetition of a general process. In the contraction of the earth the edges of adjacent plates 1A review of “Der Bau der Erde,’ by Leopold Kober. Berlin, 1921. Manuscript received by the Secretary of the Society March 13, 1923. This paper is one of a series composing a “Symposium on the structure and history of mountains and the causes of their development.” XVI—BULL. GrEoL. Soc. AM., Vou. 34, 1922 (231) bo JS? Cc. R. LONGWELL—KOBER’S THEORY OF OROGENY have pressed against or toward each other, squeezing the relatively plastic orogenetic zones and thus localizing folded mountains. THEORY AND WoRK OF SUESS In studying the genetic relationships of mountains it is especially important that we recognize the largest units of structure. Exactly what constitutes a complete orogenetic zone and what does it look like in cross-section? Since the time of Suess we have been impressed with the asymmetry of folded mountains. It is a common conception that they are one-sided, the expression of intense rotational forces. Thus we speak of the Appalachians as overturned to the west, the Alps to the northwest, the Himalayas to the south, the Andes and northern Rockies to the east. This asymmetric cross-section is nowhere more pronounced than in the famous “decken” structure of the Alps, revealed in the “mountains without roots,’ which are isolated masses of older rocks standing on a base of more recent formations. It is clear that these anomalous masses are remnants of great overthrust sheets or recumbent folds,? which were pushed northward many miles from their original positions. Deep erosion has exposed a series of these sheets, or even local repetitions of a series, with rocks ranging in age from pre-Cambrian to Tertiary lying in various combinations of superposition. ‘The com- plex mass has been rolled forward over the foreland, which shows depression under the load. COMPARISON OF VIEWS OF SUESS AND KOBER ON THE MEDITERRANEAN MoUNTAIN SYSTEM Suess pointed out that several mountain systems in the Mediterranean region may be considered as parts of a much larger unit. The trend- lines of the Alps are continued through the Carpathian are into the Balkans, forming a sinuous but practically unbroken system, with over- turning in the same sense throughout. Suess also saw a westward con- tinuation of the Alps through the Apennines, the Atlas, and the Betic Cordillera of southern Spain. Thus he pictured the Alpine system as a great spiral, with its center near Genoa.* But Kober contends that the Pyrenees and not the Apennines are the proper westward continua- 2 Kober evidently favors the older conception of Swiss geologists, that the great “decken” are attenuated recumbent folds rather than overthrust plates. He recognizes a difference in structure, however, between certain ‘“‘decken,”” as the Helvetian, apparently developed at a shallow depth, and others, as the Pennine, evidently formed under great load. 2 He recognized the reversal in direction of overturning in passing from the Maritime Alps to the Apennines. COMPARISON OF VIEWS OF SUESS AND KOBER De tion of the Alps. Furthermore, following Termier, he considers the Betic Cordillera as entirely distinct from the Atlas and probably con- nected with the Pyrenees. Proceeding to the east, he projects the Balkan trend-lines through the structures of Crimea and the Caucasus. Thus the Alpides, as defined by Kober, extend from Gibraltar to the Caspian ; and in all subdivisions of this great system overturning toward the north is pronounced.* CHARACTERISTICS OF THE MEDITERRANEAN RANGES The Alpides, considered alone, furnish an excellent example of asym- metry in cross-section, corresponding to the conception of Suess. But Kober says this is only half of the picture. A remarkable counterpart of the Alpine unit may be traced through the Atlas, the Apennines, the Dinaric Alps, the structures of Greece and the Grecian Isles, into the mountains of Taurus and Iran. Again we are dealing with a tortuous but practically continuous line of mountains, with structures overturned FIGURE 1.—Schema der Gliederung des alpinen Orogen Kober’s figure 26, page 140. in the same sense throughout; in this case southward, away from Europe and the Alps. It is clear that all of these Mediterranean ranges have a close genetic relationship, for they were born of the old sea Tethys during Cretaceous and Tertiary time. Considered together, they out- line a complete orogenetic zone, or orogen, with the following char- acteristics : The two parallel systems are overturned away from each other, each over its own foreland. Measured from one foreland to the other, the average width of the entire unit is about 1,000 kilometers, although locally it varies considerably from this figure. Typically, as in the Hungarian lowlands and in central Asia Minor, a broad intermontane *With regard to the Caucasus, Kober is at variance with several other geologists, including Suess, who have reported these mountains as overturned to the south. 234 C. R. LONGWELL—KOBER’S THEORY OF OROGENY space—the Zwischengebirge—is relatively little deformed. Elsewhere, as north of the Adriatic or west of the Balkan arc, the border ranges are pressed back to back, with no intervening space. Due to unequal stresses or partly to an original irregular course of the orogen, there are local deep embayments where ranges of the same system face each other. The most pronounced of these irregularities is represented by the Apennines and the Dinaric Alps. Kober’s orogen® of the Mediterranean type is represented in section as well as in plan by figure 2. The degree of bilateral symmetry shown in the diagram is, of course,’ ideal, but with certain modifications we may consider that the section is taken on a northeast-southwest line through the Carpathians, the plains of Hungary, and the Dinaric Alps. Figure 3 represents a section farther west and more nearly in a north- TAMIR ih if ue hiked it ins. FIGuRE 2.-—Blockdiagramm eines normalen (erweiterten) Orogen KkXober’s figure 30, page 166. south direction, crossing the East Alps and the Dinaric Alps. This part of the orogen has suffered such extreme deformation, that the rocks of the middle zone (Zwischengebirge) are either incorporated in the overfolded borders or depressed into the depths. Folds have been squeezed into recumbent sheets or “decken,” which are most pronounced in the East Alps, but also reach southward into the Dinarides. In con- trast with the normal section, the separation between the two systems of border ranges is marked by a mere line or cicatrix. The Narben (cica- trix) type of structure characterizes the narrow segments of the orogen, which alternate with broader segments characterized by the Zwischenge- birge type (see figure 1). °To afford a complete representation of his type orogen the diagram should also include foredeeps outside of and paralleling the border ranges. CHARACTERISTICS OF THE But the Mediterranean orogen does not stop at the Caspian Sea. The trend-lines of the Caucasus are taken up in the border ranges of Turkestan, deflected northward through the arcs bounding the Pamir plateau, contin- ued eastward through the Kuenlun, and turned to the south on the head- waters of the Hoang-ho. A long belt of chains follows the Mekong, crosses Siam, and finally breaks off at the rias coast of the Gulf of Siam. In this long line of Asiatic chains there appears to be universal overturning in the Alpine sense—that is, generally northward. Typical “decken” structure is reported from several localities. The southern half of the Mediterranean orogen is also traceable through Asia. From the Taurus Mountains we pass into the ranges of Kurdistan, western Persia, and Oman, to the Arabian Sea. In Baluchistan there is a northward curve to join the great Himalayan arc, and in upper Burma the trend-lines are again southward, passing into Sunda arc, which swings eastward to Timor. In this long system of ranges there is consistent overturning toward the south, over Arabia, India, and the Aus- tralian platform. In this entire EKura- siatic mountain belt, extending from Gibraltar to New Guinea, thousands of miles in length and hundreds in width, there is a remarkable correspondence wn kind and age of sedimentary rocks, in kind and age of structure. Evi- dently we are dealing with a great structural unit, an orogenetic zone which has been crushed between rigid ‘OSL osed ‘27 BINSY S,19qoyy MEDITERRANEAN UapPlNWG pun Uad{nj{sSQ sap sannquaysag sap nwayoV—E TUNDYIYT RANGES SSS SS an a a a a yosdjy assejow Vedjeniey -! ' 4 ‘8 Gl oe ~ aeate = oe ae Vee ae fa °eé aie te os ry ‘ yc Sa he BOCES 2 ened ra = ‘ ‘ iran mre ,o +o ,a i 2 \e nd = 4 ‘, 2°? -Guen bul 239 | ef , Oly ch reas .o . ong o Ne ay 3 Ant ey een , Int ) Jd, beer WEUOg SOOT QZ LL YN ) Os Te Hlor S ulgiog = udshi3 — vadry JeUias.. | 236 C. R. LONGWELL—KOBER’S THEORY OF OROGENY plates of the crust. The northern foreland is Eurasia, the southern a combination of Africa, Arabia, India, and Australia. Intensity of over- turning varies from place to place, as do the width of the orogen as a whole and the distance between border ranges. The greatest of the inter- montane masses forms the high plateau of Tibet. COMPARISON OF THE MEDITERRANEAN OROGEN WITH OTHER MOUNTAIN SYSTEMS We may say, then, that the Mediterranean orogen exhibits bilateral — symmetry in section, and its ranges are grouped systematically in ground plan. It will be well to examine other mountain systems for evidence of similar relationships. Paleozoic mountains have been eroded, frag- mented, buried.under later sediments, and therefore in many cases the complete plan of their architecture is not evident. Thus in the Altai Figure 4.—Blockdiagramm eines mit einem Vorlande einseitig versenkten Orogen Kober’s figure 33, page 167. Mountains we see overturning to the north, over the old Siberian table, but farther to the south the structures are obscured, due to later deformation. In the Urals a partly resurrected Paleozoic system, folds, and “decken” reaching both east and west are exposed, conforming to Kober’s theory. A still better illustration is found in the post-Silurian Caledonian Mountains, represented on one side by the great Scandinavian overthrust to the east and on the other by the Scottish overthrusts to the west. The middle portion of the orogen has sunk beneath the sea. We turn now to the Western Hemisphere. ober has read of struc- tures overturned westward along the Pacific coast of North America, and of the Rocky Mountain overthrusts to the east. He seeks to join these widely separated features to form a single orogenetic zone. Those who are familiar with the mountains of western North America will not consider this interpretation seriously. It appears, however, that a sug- gestion of Kober’s plan exists on a more limited scale in the Jurasside structures of California and Nevada, which exhibit overturning to the MEDITERRANEAN OROGEN COMPARED WITH OTHER SYSTEMS 297 west in the Sierra Nevada Mountains and thrusting to the east in southern Nevada.® In the Appalachians evidence has seemed to indicate overturning toward the west only; but Kober reminds us that the old land Appalachia has been completely submerged, and he believes the eastern half of the Paleozoic orogen has foundered with it. Support of this theory would be furnished by finding along the Atlantic coast rem- nants of structures with overturning to the east: FIGURE 5.—Blockdiagramm eines normalen versenkten Orogen, dessen Vorland 2, T. stehen geblieben ist Kober’s figure 31, page 166. He uses similar argument in the case of the Andes, where dominantly eastward overfolding and thrusting have been reported. An old land- mass to the west has certainly disappeared, and he believes the western limb of a great orogen went down with it, leaving only the eastern border ranges exposed. This explanation calls for selective faulting on a rather large scale, for it demands quite accurate cleaving of an orogenetic Japan INnine= pin Wa cam re (| | mn Yictre 6.—Blockdiagramm des japanischen Orogen Kober’s figure 34, page 168. zone along its median line throughout the length of a continent. But Kober thinks we should expect various modifications of the typical orogen. One foreland may be submerged and one entire system of ®° Evidently Kober is not aware of this relationship, and it appears that he does not consider the great discrepancy in age between the folding in the Sierra Nevada and the Rocky Mountain thrusting. Other erroneous conceptions are evident in his dis- cussion of North American geology. 238 Cc. R. LONGWELL—KOBER’S. THEORY OF OROGENY border ranges with it (figure 4). Parts of both forelands may break down, carrying the entire orogenetic zone, perhaps leaving the tops of border ranges projecting above sealevel as chains of islands (figure 5). The island chains east of Asia may represent a combination of these two modifications (figure 6). The eastern foreland is covered by the Pacific; a typical foredeep borders Japan; the Yellow Sea is a shallow, partly filled foredeep, and the western foreland is partly broken . RY FIGURE 7.—Blockdiagramm eines samt dem Vorlande versenkten Orogen i} Kober’s figure 32, page 167. down. Again, both forelands and most of the orogen may be submerged figure 7). Perhaps this type is represented by the island chains of New Caledonia and the New Hebrides. The suboceanic ridge extending north and south in the mid-Atlantic may be an orogen of which no portion rises above sealevel. MouNTAIN GROWTH What forces are involved in the building of a two-sided mountain system and how do they operate? The motive power for folding and thrusting is probably furnished by contraction of the earth. Compression due to contraction is, no doubt, continuous, but in any orogenetic zone periods of deformation alternate with periods of quiet, during which stresses accumulate. But the requirements of gravity must be satisfied in the crust. Tangential movements, with localization of deformation, tend to build up an excess of material in an orogenetic zone, which then subsides under the overload. If subsidence is sufficient, the zone be- comes an area of sedimentation, and is further depressed under the weight of detritus. This marks a geosynclinal or negative stage. As the zone sinks, the geisotherms are depressed; then slowly rise. The increase in temperature and resulting chemical reactions probably do not affect the crust of sediments so much as the deeper portion of the lithos- phere beneath the geosynclinal area. Energy arising from the reactions MOUNTAIN GROWTH 239 and from thermal expansion probably serves chiefly to disturb equi- librium, setting in motion the larger forces due to contraction. The materials of the orogen become more plastic with heat—perhaps portions actually liquefy—and the deeper part of the zone becomes honeycombed with magma. Under lateral pressure from the rigid plates the plastic mass tends to rise and the overlying sediments are folded. The entire orogenetic zone acts as a passive mass between the jaws of a vice, and as great folds rise on either side of the geosyncline they are underridden by the rigid plates, and so turned back over the forelands. Other folds form inside of and parallel to the first, and if compression is intense and long continued the entire body of sediments will be crumpled. In a wide geosyncline the forces will ordinarily be spent in folding up the border ranges, and the sediments of the middle zone will escape intense crumpling. This interior (Zwischengebirge) zone occupies the deepest and most plastic portion of the orogen. There isostatic compensation will be almost completely maintained, even during periods of active mountain growth, and very little actual elevation may occur. The rigid plates in part support the overfolded border ranges, and thus in some degree superior elevation may represent an overload. Yielding to the overburden may take the form of sagging or major faulting, either at some stage of mountain growth or at a later date, and considerable portions of a foreland may be carried down in tlie failure. Kober’s ideas of mountain growth as illustrated in the Alps are best expressed in his own words, as follows :* . “The Alps arise on the site of the Paleozoic mountains. During the Mesozoic these were in large part leveled down and sank more and more into the geosyncline. But not all parts alike. The pressure from contraction allows some parts to sink deeper than others, and thus there are formed more or less parallel sea basins on the floor of the geosyncline lying in the area of contraction. Major synclines and geanticlines originate, alternating from north to south. The great anticlines become embryonic decken; these change in the course of mountain-making through the Mesozoic to trunk decken, from which secondary decken (Teildecken) later branch off. The decken move slowly and steadily on the sea-floor against the foreland, gradually rise above sealevel, develop into islands, rows of islands, island chains, and finally into connected mountain features (Argand and Staub). It is a ‘mechanics of great folding,’ as we may say with Abendanon, a moving of ground folds {Penck), which increases in magnitude, develops into geanticlines, between which great synclines lie deeply depressed. The geanticlines are finally over- turned; their own weight drags them down into the synclines; these are concealed (overthrust). A period of quiet follows. Then the next geanti- cline is thrust forward. The process is repeated. Then the previously formed geanticline revives, is thrust over the one lying before it; both move together 7 Der Bau der Erde, pp. 92-93. 240 C. R. LONGWELL—KOBER’S THEORY OF OROGENY farther on the foreland and cover the area in front with their decken wall, or thrust it forward, squeeze it, overturn it. Phases of quiet follow intensified mountain-making. This is all plainly expressed in the sediments. The brec- cias always originate during the phase of unrest; they define the manner of mountain-making as to time and place, and are therefore valuable guide horizons in unraveling the genesis of a decken mountain system. The con- ditions of sedimentation become increasingly complicated with the evolution of decken. Out of the rubbish of the decken, strata may form on the sea- floor, which in turn are made into decken. “The decken movement is from the inner parts of the geosyncline outward, ‘and it advances continually against the rigid plates of the foreland. This. - also may be included more or less in the powerful movement and drawn into: the whirlpool of the orogenic field of force. The more the geosyncline is. compressed, the more will it rise as mountains and become terra firma. There follows the phase of arching up the decken ranges into lofty mountain chains. Steinmann has designated this phase as positive mountain-making. According to Heim, this phase is followed by a further one, which is char- acterized by the sinking of the mountain chain, immersed like an iceberg in (ary mM (ll tt IiGgtuRE §.—Schena des Graben-Horsttypus Mi IXober’s figure 1, page 51. the sea, aS a consequence of its enormous size and weight. This is a sort of closing phase in the making cf a young decken mountain system. Perhaps this may be designated as the negative phase. The positive phase is char- acterized by the division of the mountain system into blocks (Schollen). The mountain chains rising out of the sea remain for a long time near sealevel, and undergo there widespread planation, as is seen in the East Alps (pre- Miocene, pre-glacial surfaces). The Alps at that time had not the character of a high mountain system. They were rather a hill country or mountains of moderate height. Only positive mountain-making forced the Alps to great heights. It is said that these movements are epeirogenic.. As a matter of fact, they are expressed chiefly in fractures and flexures, in arching of the old land surface. But these epeirogenic movements, aS was stated previously, are disguised orogenic movements, involving fractures which may later become overthrusts. In any case they are not movements of an entirely different sort, but merely continuations, through a short time interval, of the orogenic or decken movements.” MOUNTAIN GROWTH QAI Throughout his discussion of diastrophism Kober emphasizes the part played by compressive forces, which probably have their origin in con- tinued contraction of the earth body. He even conceives that horsts and graben in a region of block-faulting are bounded typically by reverse rather than normal faults (figure 8). The Rhine Valley and the African Rifts are explained by failure at the crests of broad anticlinal arches, and so are essentially features due to compression. Unlke many exponents of the contraction theory, however, he is alive to the import- FIGURE 9.—Schema cines Gebirges mit Massendefekt (Dotted line represents theoretical surface of normal gravity.) Kober’s figure 21, page 97. ance of isostatic control. Rehef features are largely compensated,. mountain ranges standing high by virtue of deficiency in density (figure- 9). When an orogenetic zone is undergoing folding, more material is forced into the depths than above the general surface. ‘There is con- tinual conflict between tangential and vertical forces. If excessive mat- ter is crowded into a zone, sinking will eventually ensue, although a. certain degree of overload may be borne for a time. Thus uplift and subsidence may occur alternately in essentially the same zone through: several geologic periods. - = pA Ps - 3 N ¥ = 2 - a G ‘ ws al “ ¥ » ‘ & Sat rt tS ati LN, 5 ot, 5 ; tT Re eA ae x * ee. b iJ ~ oe C cd = , : c 5 * oF ws —— a ¥ ‘ . V ¢ Gea a eyes BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 243-252 JUNE 30. 1923 THE ASIATIC. ARCS? BY WILLIAM HERBERT HOBBS (Read before the Society December 28, 1923 CONTENTS | Page- Reece dennijion Of bilateral SyMMetry ... 6.6 e. esc eee se Sea e seen 243: Assymmetrical arrangement of ranges.............-eee eee BER alae 243. Wiews Of Kober. 2. wi. oe. ee eee EE Rg as Nee Spier 08 hie ye SO 244 Suess’ theory as to mountain arcs............ i eee we ammas she i Sree 245 Be a Oa aes 245- “Author's views and conclusions...........-... Fa ey aint e ata “DAA W. H. HOBBS—THE ASIATIC ARCS blanketing slide or nappe, there appeared the first volume of Suess’s Das Antlitz der Erde, in which the pregnant idea of the unsymmetrical mountain arc was shown to have an almost universal application. Over- coming the most stubborn opposition, the idea of one-sided (etmsettigen) as opposed to two-sided pressure (zweisettigen Druck) at length made converts. even of its enemies, notably Lugeon and Heim, who are today the foremost expositors of the doctrine of one-sided compression. Views oF KoBER Ignoring all the evidence derived from the plan of the ares, it has remained, strangely enough, for a Viennese student of mountains, Leo- ‘pold Kober, to revert to the now long-abandoned idea of symmetrical bilateral disposition of the compressive mountain-building forces. The Alps are by Kober connected up to the Atlas Mountains in Africa as though they comprised a single folded area, and the well-known pro- files have been so distorted as to make a supposed folded zone, about one thousand miles across, extend downward into the earth’s shell a distance of some 300 miles, so that horizontal compression might appear to get enough “hold” to compress the lens—but what Kober draws as a wedge— of sediments, on which the forces are none the less made to act at a very acute angle. Such a symmetrical distribution of forces he then by an even greater distortion of the known profiles has made to apply to most other folded mountain ranges. There are four well-known regions, and four only, where by extending from one range to another across broad intervening non-mountamous areas, as Kober has done, such a bilateral symmetry can be made out. Three of these are on the site of the former Sea of Tethys and its exten- sions—what Emerson has called the zone of the intercontinental sea? and the author the twin zone of the earth.* The fourth example is that of the South Shetland Islands, lying between the southern apex of South America and the Antarctic Continent. It may fairly be claimed that among students of mountain formation the idea of “one-sided” as opposed to “two-sided” compression has re- ceived general acceptation, though for correct terminology we should say that what the idea involves is really an excess of lateral compressive stress from one side of the folding range, which results in actual movement of a portion of the rock layers from the side of the greater stress toward that of the lesser. 2B. K. Emerson: The tetrahedral earth and the zone of the intercontinental seas (presidential adress). Bull. Geol. Soc. Am., vol. 11, 1900, pp. 61-96, pls. 9-14, figs. 1-7. 2 W. H. Hobbs: Earth evolution and its facial expression. Macmillan, 1922, p. 92. AUTHOR’S VIEWS AND CONCLUSIONS 245 Surss’ THEORY AS TO MouNTAIN ARCS To account for the mountain arcs, Suess claimed that the system of stresses which produces them has an unbalanced thrust from the rear, and this view has since been quite generally accepted. In his Hrin- “nerungen, which were published posthumously in 1916, he reveals more clearly than anywhere else that he came to adopt this conception because of the position of the Bohemian “obstruction” of granite and gneiss in Europe opposite the vertex of the Alpine and Carpathian arcs, which arcs appeared to him, therefore, to have moved northward at either side where not so “obstructed.” Probably also unconsciously the fact that viscous substances flow outward to produce convex borders played some part in fixing this conception in his mind. AutTHOR’s VIEWS AND CONCLUSIONS Mountain ares are, however, very numerous, and such obstructions along their front as the Bohemian mass are altogether exceptional, the only other noteworthy example being that of peninsular India. I have therefore examined the question of the mechanics of arcuate mountain formation and reached the conclusion that the excess of tangential com- pressive stress which is responsible for the evolution of the folded arc has come from the front and below instead of from the rear and above.* The Asiatic ares taken together comprise by far the most perfect illus- tration of the folding process that our planet affords. They represent a more or less concentric series of compounded ares which surround the ancient continent of Angara, with each series made up of a number of arcs linked together. Their study has shown that they have been formed in successive periods, and this not alone on the basis of the strata involved in the folding process, but quite as certainly by the stage of the erosional process which each illustrates. It is a generally accepted fact that the effect of close folding is to give to the strata affected additional rigidity, and this should have the effect of causing the area in process of folding to migrate beyond the already formed folds, though such stresses appear to be limited as regards the distance to which they are carried forward within the folded layers. The well-known experiments of Willis on the folding of strata confirm this view. The plan of the Asiatic arcs is so extended that it is possible to apply a test to determine what has been the sequence of formation of the *Harth features and their meaning, 1912, pp. 437. Mechanics of formation of arcuate mountains. Jour. Geol., vol. 22, 1914, pp. 71-90, 166-188, 193-208, figs. 39. Earth evo- lution and its facial expression. Macmillan, 1921, chapter x. 246 W. H. HOBBS—THE ASIATIC ARCS several festoons of arcs—their order of succession in time—and so to determine whether the deforming unbalanced stresses have come from the front or the rear. These festoons of arcs bear such close relations to each other as parts within a system that what has been true of one has in a general way been true of the others, as regards the method of their formation. In other words, we are here dealing with the large problem of the deformation of the continent of Asia under the influence of a system of crustal stresses which have acted over a long period of time and have involved vast areas. As a part of this system of arcs, the festoons of islands which parallel the coast are from the relation of their design to that of the ranges upon the continent to be included in the system. The striking difference between the several arcuate series within the system, both as to the ages of the strata involved, the topographic development, the erosional stage, et- cetera, indicates that they have been formed at different times; and since these differences are in a noteworthy degree graded from the interior of the continent toward its margins, they may be assumed to have been formed in succession. ‘The question is whether the interior or the ex- terior arcuate series is the initial one in the succession, and this will obviously depend on whether the surface shell of the hthosphere has migrated after the fashion of a glacier in the direction of the surround- ing seas or whether a thrust coming from the seas and directed against the borders of the continent has in successive stages raised a ruffle along its margin. The maps and accompanying sections of figure 1 represent an attempt to set forth these contrasted views with their necessary corollaries, the first (map and section A) setting forth the generally accepted view of Suess that the thrust has come from the back of the arc, the second (map and section B) the view of the author that this thrust has come from the front. Mountain ranges in process of erection are well known to be zones of seismicity and to be further accompanied by active volcanoes, and these elements have been introduced into the maps. Moreover, inasmuch as erosion is always in sensitive adjustment to uplift, the degree of denuda- tion which should under each of the views be expected in each series of ares is displayed in the sections. Especially to be noted is the condition of marked compression from opposite sides of the arcs within the southeastern extension of the conti- nent in the direction of Australia. In case the outer skin of the continent of Asia is conceived to have migrated centrifugally, as imphed by Suess, the position of the ancient coign of Australia should have the effect of broadening the arcs in proportion as they approach this “obstruction.” AUTHOR’S VIEWS AND CONCLUSIONS QAT On the other hand, if the system of thrusts has gone out from the oceanic areas and been directed against the margins of the continent, the coign of Australia must be regarded as a protective shield which has warded off any thrust from the southeast, while the thrusts on the Malayan region ‘from its opposite sides (northeast and southwest) should have resulted in a much greater compression of these arcs than is elsewhere to be found. In a broad way, the map and section B represent the facts so far as they are known. An obvious cause of the landward thrust from the sea, which is here invoked as the cause of formation of mountain arcs, is the still continuing subsidence of vast areas in the Pacific and Indian oceans, to which the formation of the groups of atolls bear testimony. The marked zone of seismicity and the line of active volcanic vents which alike follow the course of the festoons of islands off the coast of the Asiatic continent seem clearly to reveal them as the very youngest of the Asiatic arcs and those which are in the process of erection today on the floor of the sea with their summits just emerging from the waves. Be- heving that, in geology as in zoology, it is in the embryo that the life history is often most clearly revealed, the writer during the summer of 1921 carried out a reconnaissance of these youngest arcs, in connection with which he visited islands of the Bonin, Sulphur, Marianne, Caroline, Pelew, and other groups with a view especially to find evidence of con- tinuing mountain growth and to check this by observing the stage of the erosional process, as well as the nature and comparison of the reef struc- tures on the opposite sides of the arc. These latter are of particular value in revealing the structure of an anticline, and in practically all earlier stages of arc formation proceeding within the tropical seas, wherever conditions suitable for reef-making have existed, elevated reef-caps ap- pear as terraces on the convex outer side of the arc and barrier reefs indicating subsidence on the opposite or concave side. In a later stage of arc formation alternating vertical movements of great amplitude develop along the medial portion of the convex side of the arc, so that here also barrier reefs develop. These central zones off the front of an arc in a late stage of its development are regions of special unrest of the sea-floor and in this respect surpass anything which is else- where known. Here are the special loci of seaquakes which have been such a menace to the navigator, while at the same time the arcs are the vigias or sign-board warning of the danger. The erection of an evolving anticline does not appear to take place at a uniform rate throughout, but there first arise a series of domes in arcuate arrangement which only later unite to form a uniform crestline Ve Born, GEOL. Soc. Am., Vou. 34, 1922 ARCS ASIATIC W. H. HOBBS—_THE 48 2 ‘SOIR ULB} UNOU OY} JO UOLSsoddUs JO AoPLO oO} SULULIIU0D (QZ) SATOA S.1OqJNV oY. puR (Vv) SSOUQ JO SMITA VY JUSoTdot JUIULZUO) OLpDISy 942 JO SUOlpay puDd sdv papsnsquog—T auaniyy Q@ dop sayonbujuva puo seaouvdsj0n ...-. sou0 buno, SQUD DLO;/Pawusjul — —— Ssou0 =jUe!SUYy DNAS aa JUSUIYUOD pUGUI}UOD SSUIMBIP OSVUT, AUTHOR’S VIEWS AND CONCLUSIONS 249 for the are. In this respect the writer’s view differs materially from that of Brouwer, who sees in the straits which separate the islands of an arc the evidence of late tensional movements which he supposes to result from a forward migration of the arc by a push from behind.’? The evi- ‘dence that the arcs of today rise first at special points appears to be con- firmed by those older arcs which skirt the eastern flanks of the Rocky Mountains.® No sooner does an anticline rise to form an arc than an elongated and roughly parallel trench—fore-trench—begins to develop along its front, and the crucial test to determine whether the arcuate arrangement of a eroup of islands may not be fortuitous, and hence without tectonic sig- nificance, is exactly the presence or absence of such a fore-trench. Hence the great importance of carrying out an elaborate series of soundings in the neighborhood of all growing mountain ranges of the oceanic areas. There is in the development of the fore-trench opposite a rising are an apparent indication that the void which should tend to develop beneath a rising arch in the strata is met by a lateral migration of subsurface material from in front of the rising anticline—an isostatic adjustment which follows as a consequence of mountain erection, but is in no sense an initiator of it. The anticline and syncline from this stage appear to develop together. In those later stages where arcs have taken on a sharp curvature the trench appears at the back instead of the front of the are, notably in the examples of the Moluccan and Windward arcs. Within coral seas where atolls are to be found, the earliest evidence of arc formation may be the elevation of such atolls, and these may be de- tected today in very many cases by their deposits of phosphate, such islands being far more numerous than is generally supposed.? In the study of the young island arcs, examination of each island is essential in order to determine its individual character and its relation to the arc as a whole. The study of the Marianne arc, which is in an ex- tremely youthful stage, has brought out the fact that this arc is made up of three distinct zones from front to back, and that it betrays a no less marked differentiation when examinted in a direction from end to end. At its southern end it is indicated merely by a raised atoll, that of Feys. °>H. A. Brouwer: The horizontal movement of geanticlines and the fractures near their surface. Jour. Geol., vol. 29, 1921, pp. 560-577. Fractures and faults near the surface of moving geanticlines. II. Abnormal strikes near the bending-points of the horizontal projection of the geanticlinal axis. Proc. Roy. Acad. Sci. Amsterdam, vol. 25, 1922, pp. 229-334. ® Earth evolution and its facial expression. Macmillan, 1921, pp. 139-142. “W. H. Hobbs: Les guirlandes insulaires du Pacifique et la formation des montagnes. Conférence faite 4 la Sorbonne le 29 avril, 1922. Ann. de Géog., vol. 31, 1922, pp. 485-495. bo Or or) W. H. HOBBS—THE ASIATIC ARCS coALAMAGAN 1 | LEGEND / —— -— Main arc, outer edge j ZEALANDIA BANK BS Zone ob extincr 0 SERIGAN L volcanoes / w | 2 Zone z Ele ou 4 v0 vy | een . f ‘ f w ' ‘ BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 263-284 JUNE 30, 1923 STRUCTURE OF THE ROCKY MOUNTAINS IN IDAHO AND MONTANA? BY GEORGE ROGERS MANSFIELD (Presented before the Society December 28, 1922) CONTENTS Page CHEE OC biG 506) eh a a re ee MEP ear a Ph es cues ean eee wee ec GRE S, fe es folie a OS eigen AN Ud Ath TeCSERVAEIOMN « ve cie os 6 2 ote sas cook Sieh! Bic dl eteseye's bilddel ess Owlewe was 264 Poe SOU EM et Or MOUS. 400s ae bie cheliowie.e be ccdeielip ema wale wet cies cee LOD ae OTM SUNN poet a inte ve tne! ar Nah ec aus ate Grebe & ofa lcse Sie viele Bee SiS weve elds & 266 Mam MIGnrte: VOrENeTIY TOCKICS <0 550... ate See occa eee end eee e eo cewsee 266 imei iS Or. PRE. NOFLNETN ROCKICS. Albert Heim: Geologie der Schweiz, Bd. I, Leipzig, 1921, pp. 647-649. 26 R. 'T. Chamberlin: The Appalachian folds of central Pennsylvania. Jour. Geol., vol. 18, 1910, pp. 228-251. 5 : The building of the Colorado Rockies. Jour. Geol., vol. 27, 1919, pp. 145- 164, 225-251. NS MOUNTAI ROCKY STRUCTURE OF G. R. MANSFIELD WJoL OU) Ve osuRy Godsy oy OYPPL UddPSvOYINOS JO SUDZUNnO PW Ayoogs ay if z 4 by (J) Ne, (Dh Meme Re Ee / a bag k ie / Sei % / Sas 7 s tafe / lay Once pu eae 7 re *SPann if vanseesy, / ee iy baer Sig) as Me ae ) bs IG eel 2 : i [ + yr: --” / Suppnypour ‘uoppoos of} JO Javd WaropsoMpNog OY). UW) OANQONADS JO WOLDsOp say papduwa, yy & wap ty lee ie Sey we es MDON NY Ss sae a i cea cal 7 / LSnyuULUaro o1sseldy, ae o0°@ Pian, OS | Jeeerer este, eS heme bt ol | owe ¥ bt | (Cc) oisseiRrp H in eee . | a F Renate SME e000e oot oe? Y ont Peco Bos I set Mere 5. ( RESTORATION OF STRUCTURE IN ROCKY MOUNTAINS LYDIA OY. WD ADUDE NOQwnO AY. YLA fe IND Wb UALOYS UOoaG duds dYyZ JO UOYWMHUYUOD UsaysvayJAON-— YG AAAI ee oe le Ss ee ee ee ee ee SWS y = rz " fo) “TatA arr vas & Snoisyuocqre> i : c LSNUYHLYSAO MOONN WE ' ad ce Be Bryeuens % 4 INL G : Li AT gaN (1) 4, ) 6) Pan eneg! 7 LA os) > ¥ | ad, i oc°00S Ce ame tao es tests : prorece tesssesee eccserees saver geass astrsteretreres Ses = sefiusieifesgipieaiisnatnetnstetestc seeesestetetttiest? Harare eee HIHInsirifeaseetess= pet sasasseesteeesetes eeetezess ROSS8 ReeEss “ Ta! Srsssereesbssesas noes : Scsscscessteesstczesseees : Sesesssess ssesescees SS Sesatesssssatvetonet eresgesset ners eseeereesa Sasan' Bess nesssesesrasesesseseesessest oe jeaen' —----- 2 a / | ="p oRGme| saan Gousasenenceeen Bi case HH Seenues' shsscssesssessssssessessssesesserssessss oe ALISEGAIN? T1aNd09 “BHIETIWIONA TAI dO 2827109 JW2 40 SQIBOLEHORYE 302 W.T. LEE—BUILDING OF SOUTHERN ROCKY MOUNTAINS It is obvious that without surface changes capable of initiating move- ment, such as the changes in load by erosion and deposition, internal forces tending toward deformation of the earth’s surface must ultimately reach equilibrium. Such a condition of affairs could be reached only when erosion and deposition are absent, as on the moon. The height to which mountains can rise on a globe lke the moon, on which there is no atmosphere, is. dependent on initial temperature, force of gravity, and plastic properties of the materials constituting the isostatic shell; they should, therefore, be capable of determination by the methods of mathe- matical analysis. Prof. R. S. Woodward® has solved a problem which gives a measure of the effect of change in surface temperature on the earth. He assumes that the mean annual temperature over the Bonneville Basin was raised 10 degrees Fahrenheit. The change in elevation of the basin due to the change of only 10 degrees Fahrenheit in the mean annual temperature for different time intervals is as follows: Time interval. Changes in elevation. Years Feet 10,000 0.41 100,000 1.26 1,000,000 4.06 50,000,000 20.7 100,000,000 41. These figures show that even moderate fluctuations in temperature on the surface of the earth, covering long intervals of time, produce forces which tend to check subsidence and initiate elevation, or, conversely, they may check elevation and initiate subsidence. A rise of 25,000 feet in 5,000,000 years, as shown by Lee for the Rocky Mountains, is equivalent to a uniform rise of 0.005 foot per year, or an extension, e=— Whe x 10a in a column of rock 60 miles in height. That is, 60° 5280 & 1578 > 20 5 0.00 a t008 or a little less than 1/16 of an inch in one year. The rocks in the crust of the earth are always in a state of strain; consequently we are not concerned with initial strain, but a subsequent strain or flow in the rocks due to carrying loads for long intervals of SR. S. Woodward: On the elevation of the Bonneville Basin by expansion due to change of climate. U. S. Geol. Survey, Mon. I (Lake Bonneville, Gilbert), 1890, pp. 425-6. UALS AOPUN Jo1UdIDTY pyNos Jo yuawmysn(pvay—g9 aUNnyIA “SAV — WIL Vee =s sages el pee Pst ob led A | NOTES ON ISOSTASY 303 INCREMENT IN LENGTH — WAVE LENGTHS. £ Sesv oboe ces aeze ae wk 39S : Ieqge okin x jo RESIDUAL INCREMENT IN LENGTH — WAVE LENGTHS. 304 Ww. T. LEE—BUILDING OF SOUTHERN ROCKY MOUNTAINS time. Some indication of the behavior of rock material under continuous load is given by an experiment conducted a few years ago by Mr. H. D. Ayres in collaboration with the late Dr. George F. Becker and myself. A steel tape—cross-section, 0.0162 0.6365 centimeter; length, 27.906 centimeters—was subjected to a load of 10 kilograms (less than one- twentieth of the breaking load) for a period of 126 days and then re- leased. On account of certain defects beyond our control, we were unable to decide whether or not the tape returned to its original length, but the following results on the increment in length of the tape with time, due to the load of 10 kilograms, show that substances like steel do not neces- sarily reach equilibrium when subjected to continuous stresses well within the so-called elastic limit. The results are contained in the following table and platted in figure 6: Load, UD SUG SENS: No load, following load of 10 kilograms. | a a ae ae aa ae a er a SG SN Time Total increment, Time Total increment,, ixterval. wave lengths. interval. wave lengths. Ey, MINUS ates Mies Paoteuco eee eels 439 .82 Dy SAU Seeees ee 4.31 TY OURS Bede © orate 440.12 th “ROWE, C5 eae, cok ee g Bae 12 ts A ope oma opt ae nee leo ck 440.89 LOPES os Saal a dere ee ee LO: GRUYISE-okc..8 J Busieree crete 441.99 10. daysvad os «s sistte coeur 2.63 WG ss ARV Sis is sda ecg are renee 442.42 TO: Gays reece hata gntiet th Se toy oS 1.32 SO Gla Sewer. acy aeicanths eet mre 442 .69 SO CAN Si2 as ests Be rr ey nt 1.08 BO (GAISEHe RS eas oe Ete aco enene 442.88 AQ NA BYS Societe kee a eee 1.00 AD" AV SReae ike, aie dhe erates arene 443 .04 BO), aaySi.ai Zetia. vogtnerese eee 0.87 GO: “aye oae is. © Seat ee: 443 .23 60 "aysSs Aisa se ee eee 0.85 SO; Cay Sere eee EN Te 2» 4437-58 TOAGAYSEE SY CS nee eee 0.61 LOW. dialiy Sey eseeccters passes ore nies 443.68 LOO ays eer See 0.46 DIA: (AVS ache eee neha 443 .82 LOS. GAYS. cass henge Eee eee 0.44 P2G GAY Sacto sack Ge Sr eioes 443.93 NAD. AVS aie oli Soe onctepe sais eee 0.50 Curve A of figure 6, which represents the data in the first two columns of the. table, shows that the tape would have continued to stretch for a much longer interval of time. On the other hand, the data in the last two columns of the table, represented by B in the diagram, shows that the tape had almost returned to its original length at the end of 112 days. The temperature of the tape during these tests was 27.1 degree centigrade (80.8 degrees Fahrenheit). It was found by means of a least square solution, using 12 observations between the 101st and the 126th days, inclusive, that the tape lengthened during that time at the rate of 0.00944 wave lengths per day. Consid- ered as an extension, we have, ,__ 0.00944 & 5876 x 107 es eee NN = ope reals cee : 27.906 Sees } ; NOTES ON ISOSTASY 305: Reducing the extension in the column of rock, 60 miles in height, to a daily basis, we have for the ratio of the two extensions, Cr pyrene Xe LOr = Cogent 10 in other words, the tape increased in length by a process of flow (elastic after-effect): during the interval, 110-126 days, at a rate which was 460 times the elongation in a column of rock 60 miles in height, necessary to produce a mountain range 25,000 feet in height in 5,000,000 years by the flow of material into the base of the column. A load of 10 kilograms on the tape produced a stress of about 13,800 pounds per square inch, which is the same as the pressure at the bottom of a column of water 31,800 feet (6.0 miles), or a column of rock 12,700 feet (2.4 miles) in height. Considered as a mechanical property of matter, therefore, there would seem to be nothing exceptional in the de- velopment or erosion of a mountain range by the process of isostatic adjustment. The mechanism is due to the conduction of heat and the redistribution of weight on the crust of the earth brought about by evap- oration, changes in mean annual temperature, deposition of sediments, redistribution of large bodies of water, etcetera. The rocks within the isostatic shell are always under the influence of a system of forces which is never in equilibrium, and the resultant of this system of forces tends always to cause the rocks to flow very slowly, in the direction of least resistance. ELAstice YIELDING OF THE HARTH’S CRUST UNDER A LOAD OF SEDIMENTARY DeEposits; By WALTER D. LAMBERT The strata principally concerned in the elastic yielding of the earth’s crust are doubtless chiefly composed of material similar to the basic in- trusive rocks. The ranges of the elastic constants of the four specimens of such rock tested by Adams and Coker® were jw == modulus of rigidity from 2670 C1010 4:380 >< 10** CG. So units «==modulus of cubic compressi- from 4.650 * 10 to 7.829 « 101+ bility C.G. 8. units Hf = Young’s modulus promo. cia < 0" tocl0l80" <1 07* C2 G..5. units °F. D. Adams and E. G. Coker: An investigation into the elastic constants of rocks, more especially with reference to cubic compressibility. Washington (Carnegie Institu- tion), 1906, p. 69. 206 w.T. LEE—BUILDING OF SOUTHERN ROCKY MOUNTAINS For an average value we may take in round numbers p= 36 x 107 CG. Sumit, K== 6 KH Ce Ge Seimits, Be=9 oC 10226 GS waite: The ratio between the adopted values of », x, and # imphes that Poisson’s ratio, o, is equal to 14. The average value of o was in fact very nearly 14 for the specimens tested. Let us consider a section of the earth’s crust extending down to the zone of flow, say 100 kilometers (62.1 miles), and suppose that on this is placed a load of sediment 10,000 feet (3,048 meters) thick and of density 2.3, about that of sandstone. There are three limiting cases which may be readily computed and which may throw hght on the elastic yielding of the crust. . (1) Suppose the rock to be compressed as a fluid, with no rigidity or resistance to shear—that is, » == 0—but having a resistance to change of volume measured by «x = 6 X 10" C. G. S. units; and suppose further that this fluid rock is confined by unyielding walls at the bottom and sides, so that the only yielding is in the vertical direction and the pressure is, of course, uniform in all directions. The relative decrease in length, e, is given by the formula c=, Le where p is the pressure per unit area. This case, while probably the most artificial of the three as regards what would happen within a short time after the sudden application of the pressure, may yet give a fair approxi- mation to what would happen if time were allowed for the rock to flow— that is, we know that under the long-continued application of force the rock may lose its rigidity and » become equal to zero. (2) Suppose the section of crust to be supported at the bottom, but to be unconfined at the sides, the pressure being applied at the surface as before. The problem is then one of compression under the usual experi- mental conditions, and we have i ctl ale age (2) (3) Suppose the section of crust to be supported at the bottom, and that just enough pressure is applied at the sides to keep them from bulg- ing out. This condition is one not usually contemplated in the theory of elasticity, but the formula for it may be deduced from the fundamental : equations, ELASTIC YIELDING OF EARTH’S CRUST 307 Dea 6 (Ps 1 Ps)» | Hee=P.—o (Di + Ps), (A) Be, =p,—o (Pi +P»). J In these equations # and o have the meanings previously given; p,, p> and p, denote the stresses (positive for tension, negative for com- pression) per unit area in three mutually perpendicular directions; «,, e, and e, denote the relative changes of length (positive for elongation, negative for contraction) in the same respective directions. Let —«,—e and — p,—p be the relative change of length and the pressure in the vertical direction. By hypothesis e, =e, , sl yielding. The second and third of equations (A) then give no lateral . Dire Bem ven ker which, substituted in the first of (A), o, —) (3) sinceo = 4. The 10,000 feet of sediment exert a pressure of 6.88 X 10° dynes per square centimeter. The value of « found from formulas (1), (2), and (3) are to be multiplied by the assumed thickness of the crust in order to obtain the yielding in linear units. The numerical results are then Depression of 100-kilometer Crust by Sediments 10,000 Feet thick Case (1) Case (2) Case (3) Formula (1) Formula (2) Formula (3) 115 meters 76 meters 64 meters 376 feet 251 feet 209 feet These results are based on the assumption that the elastic moduli remain constant. The velocities of earthquake waves indicate that the moduli in- crease,’° and that at a depth of 100 kilometers we have «x equal to 9 & 10%, or 10 X 10** C. G. S. units, with the other moduli in proportion. The figures given above for the depression of the crust should, therefore, be diminished, perhaps, 20 per cent. Furthermore, these formulas suppose the section of crust considered to 1 C,. G. Knott: The propagation of earthquake waves through the earth, and connected problems. Proceedings Royal Society of Edinburgh, vol. 39, pt. ii (1918-19), p. 169. 308 w.T. LEE—BUILDING OF SOUTHERN ROCKY -MOUNTAINS be cut off from its surroundings, deriving no support from them. Uni- form pressure over the surface then gives the same yielding at all points of the section and for sections of all sizes. For any small section con- nected with the surrounding crust, the yielding computed by formulas (1), (2), or (3) is much too great. | If, however, we consider a section having a very large area and con- nected, as in nature, with its surroundings, these formulas, particularly case (2) formula (2), give an indication of the approximate yielding to be expected in the center of the area; for the outer portions of the area are so pressed down by the load on them that they afford little support to the central portion, and the latter yields almost as much as if it were severed from its surroundings. The extent of the area that may be con- sidered “large” must evidently increase with the rigidity of the crust. For extremely large areas, the curvature of the earth’s surface must also s be considered, and its effect is to diminish the yielding somewhat. <& Se a ee at ten en tm a oa re ct ie 4 i R ; Ying , a : de 3 ‘ 4 7 * Ne * NA v2 i. > ’ ho H ari ; x cd ail A ele egret ese a ve Sectlngt = yaw ndadeogle tone n> ; . ~~ 4 - “ery hi sor rs 2 , _ em * ‘ a . . | PR BATE ALA “so ¢ otnegorre : a ea ih a ; mii t 4 & { { f , ae . Vinal £ ie wet * . 4 & i ; . VOL. 34, 1922, PL. 4 = on a ae *Post Carboniferous granite Pennsylvanian (Mississippian: Devonian \ Siac : es Cambrian = Pre Cambrian 0 100 200 300 Miles SSS . 4.0.5.2) 6.2 eee 365 General * Stat@ments.. 24. .u 35 OR ore tae sc cane ee ee 365 Probabilities: 7.0.05 s deiee 5 25 eles oe eee Sis & aerieta kD Secnensi ieee eae 368 Method of attaining. horizontal MOfiony 22 .% 84.21. ee ~ 2 cle ey oe 369 Fluid, Condition. é¢.c'0s sacs ORs Ce ohgh a aie eee 6 oe eee 369 Attitude of rock partings:...: f2 5.1.0.0 02 ome at ee oe ee . 370 Prvelwded.: SASS soc! ais Gh istereis x Ses Sy sesh als sol en ace thee eee oe at2 Growing crystals...... gas 6 eR ces ck Lae Sat back arn ae rr 373 Bearines on other theories. ..0.2.0. 2.22 oe se see sae lees oe ee eee 373 UNA be. TOTES 3 s.c yaa gee cr kields «ees n * 7 < Ag + he AY): a bodes 4 ee ae aes ie te. : aS Th et a CRM ee i ae eae 25 . a= 12 o ‘ : tts » ee 4 oes ay at 4) fs - % a an : as A ? . ee -~ ~~ VoLUME 34 NuMBER 3 SEPTEMBER, 1923 - ah ; PUBLISHED BY THE SOCIETY : MARCH, JUNE, SEPTEMBER, AND DECEMBER oa ed o3” 4 Fead & ‘ . "s " x : « mt Fee i : : 2 —_ Te < 2S bs sd he ae, he ~ . s cs : A : 5 an = = i oF ¢ ot a v -. “oe ‘ - eS ; 2 ¢ ae a Some Structural Features of the Plains Area of Albers Caneed by Place an 4 tocene Glaciation. By Oliver B. Hopkins. 252): tet ae see 419-430 me _ Fusion of Sedimentary Rocks in Drill-holes. By N. L. Bowen and M. Amrousseaus.2 > 402 es a See ee ee = 131-448 et Carnivorous Saurischia in Europe Since the Triassic. By F. Von Huene_ 449. 458 a! #2 : Contribution to the Vomer-Parasphenoid Question. By F. Von Huene__ ‘459. 462 Lines of Phyletic and Biological Development of the Tehthyopterygia. a oa oa: By... Von Hiene=s_—— 2 a ee | ices a fo Is the Channel of the Missouri River Through North Dakota of Tertidey Ms ee Origin? By James’ E, ‘Todd. 2.:.226, ae a ees 491M * aes _ Merging of Carlile Shale and Timpas Limestone Formations in Southeast-— ee ern Colorado. By Horace Bushnell Patton a _ Glacial Lake Problems. By George H. Cliadwiclietia ose are 499-506 = Ordovician Overlap in the Piedmont Province of Pennsylvania and Mary- . - 9 land. By George W. Stose and Anna I. Jonas______-----__-____---. 507-524 St Appalachian Bauxite Deposits. By Wilbur A. Nelson_________--_______ 525-540 er =o ; Crystalline Rocks of the Plains. By Charles N..2Gould 22 35 ee ema 541-560 — : : Cretaceous Age and Early Eocene Uplift of a Peneplain 1 in Southern Brit- ees * oy se COlmabId. . oy: W. “L.-Uslowi 222 oe ee dae 82 ae aa ee 561-572 Glaciation Drainage on the Columbia Plateau. By J. Harlen Bretz___ ~~ _ 573-608 Range and Distribution of Certain Types of Canadian Pleistocene Con- : & at eretions: , By E.. Mi. Kindle. 2.2 2. Sle ee ee ok ae ee 609-648 a BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA .~— Subscription, $10 per year; with discount of 10 per cent to institutions and libraries and to individuals residing elsewhere than in North America. Postage ie to foreign countries in the postal union, forty (40)-cents extra. Communications should be addressed to The Geological Society of America, Prof. Charles P. Berkey, Secretary, Columbia University, New York City (or care ss of Florida Avenue and Eckington Place, Washington, D. C.) : NOTICE.—In accordance with the rules established by Council, claims for es tee non-receipt of the preceding part of the Bulletin must be sent ‘to the Secretary of the Society within three months of the date of the receipt of this number in order to be hot, gratis. - Entered as second-class matter in the Post-Office at Washington, D. C., under the Act of Congress of July 16, 1894. Accepted for mailing at special rate of postage provided for in Section 1103, es Act of October 8, 1917, authorized on July 8, 1918, ; a PRESS OF JUDD & DETWEILER, INC., WASHINGTON, D. C. met ee eee eee BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 401-418 SEPTEMBER 30. 1923 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY RECENT PROGRESS AND TRENDS IN VERTEBRATE PALEONTOLOGY * PRESIDENTIAL ADDRESS BY W. D. MATTHEW (Delivered before the Paleontological Society December 29, 1922) CONTENTS : Page LoL) CLS ITE cae SO a ae Se ee ee ie ne ee ene 401 Paleozoic reptiles, Permian of Texas and South Africa.................. 403 Mmacsiesrepines and amphibians of Germany...........0....eceeeeree- 405 ee sinosiurs of Utah and-Wast Afriea.............- 0. 0c cece e es 405 Cretaceous dinosaurs of Alberta, Montana, and New Mexico. .......... 407 ees aies NOL 2 NALUrAl OTGer. 2.202. ee ee eae beeen’ 408 eimene tMammals Of western, AMEerica. .. 2.6 sine be eee eee een c ene 408 RE Em Sea LIgPy ee ei eS a ty glee k vallen 410 Foreign researches and discoveries, miscellaneous contributions......... 412 Meneses as tO progress of recent Years. . 2.5... ke ce ee eee eee 415 MRE On TOG WOPK Yo. 5 62 cie Sok oe ce ae dee ee eee eee tae 416 INTRODUCTION In science, as in our business and personal affairs, it is profitable from time to time to look over the ground and see how much we have accom- plished in recent years. The present occasion would seem to be a suitable one in which to render an account of recent progress in that branch of paleontology with which I am principally acquainted. It is not a -cata- logue of recent publications, nor a summary of their contents that is presented in this address, but rather a report of progress, with some suggestions as to where this progress seems to be leading us. The foundations of paleontology, the documents on which our re- searches are based, consist of the collections of fossils, which are our record of the past history of hfe. The breadth and solidity of those foundations must determine both the size and the permanence of the structure that we may erect thereon. It is no small part of our duty as * Received by the Secretary of the Society December 30, 1922. XXVII—BULL. GEor. Soc. AM., VoL. 34, 1922 (401) 402. W.D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY architects thereof to examine carefully from time to time into the ade- quacy of these foundations, to condemn and sweep away such parts of our strueture as appear to be insufficiently supported, flimsy, or outworn. They may have served their purpose in the past as temporary outworks, trial sketches or models, or provisional scaffolding to aid in the erection of our more permanent structures; but they should not be confused with solid and stable additions, nor should they be allowed to outlive their usefulness. A critical review of our foundations and of their recent extension is the foremost and most important matter before us. In the early days of paleontology fossil vertebrates were known from few and mostly very fragmentary specimens. Our concepts of extihet animals were built up from the study and correlation of numerous frag- ments, supplemented largely by the analogy of living relatives of the extinct animals. The correlations were sometimes incorrect, the anal- ogies were always inexact and often misleading. Of the theories and conclusions based by our predecessors on these relatively scanty founda- tions, some have been swept away and forgotten, some have been modified in varying degree, some have been confirmed and vindicated by subse- quent discovery. The more intensive collecting of recent years, and especially the tech- nique devised by Hatcher and Wortman for the purpose of preserving the whole of a fossil skull or skeleton, have brought in year by year a larger proportion of complete specimens of fossil vertebrates. The leading American museums are today peculiarly rich in complete and well pre- served material, and the more progressive museums of Europe have like- wise adopted these methods, greatly to the improvement of their collec- tions. It is difficult to find any basis for a quantitative estimate of the in- crease in our collections, or even of any particular portion of them. So far as the American Museum collections go, the Cope Collection, gathered between 1872 and 1896, covers about 25 per cent of the catalogue num- bers, but is not in reality over 10 per cent of the collections in this depart- ment, as in former years many specimens were separately catalogued that would not now be considered worth individual record. The other 90 per cent was gathered during the last thirty years, and progressively more during the later decades. Perhaps it would be fair to say that 20 per cent was gathered from 1892-1902, 30 per cent from 1902-1912, and 40 per cent from 1912-1922. Other institutions would have proportions different from these. Probably in Yale University or the National Mu- seum the proportion of material collected and prepared over thirty years "The = av is INTRODUCTION 403 ago would be higher; on the other hand, in the newer institutions all the material is relatively recent. It is reasonable to regard the American Museum as fairly representative in this matter and to conclude that, so far as American collections go, nine-tenths of them have been obtained - during the last thirty years and nearly half during the last twelve years. _ Progress in foreign museums has not been so rapid, especially in Eu- rope, where the earlier collections were more important and the World War seriously curtailed, if it did not eliminate, all scientific activities. Yet even in Europe large additions have been made since the beginning of the century and some important ones within the last decade. Judging from what I saw of the principal European museums in 1900 and again two years ago, it would, perhaps, strike a fair average to estimate that their collections have been nearly doubled since 1900. I will try to specify the more important points in the progress of the last ten or twelve years. Pavzeozoic Rerrites, Permian or Texas anp SourH Arrica On the origin of land vertebrates there is little to report in the way of new discoveries, although the researches of Gregory and Watson in respect to the relations of the earliest land vertebrates to the fringe-finned fishes have advanced our understanding of the problem; nor have any impor- tant new collections been made among the earliest land vertebrate faunas of the Pennsylvanian period. Moodie’s monographic revision of the Coal Measures amphibia and reptiles affords a most valuable compendium of what is known up to the present time. In the Permian faunas, both in Texas and South Africa, there has been a great advance, both in collecting and research, continuing the activity of the previous decade. Professor Case,” of Michigan University, and the late Doctor Williston,’ at the University of Chicago, have been the ~ leaders in this country, and have secured and described large collections from Texas and Oklahoma and greatly increased our knowledge of this ancient vertebrate fauna. The Cope Permian collections at the American 2R. L. Moodie: (1916.) The Coal Measures amphibia of North America. Carnegie Inst. Pub. no. 238. 2E. C. Case: (1907.) RBevision of the Pelycosauria. Carnegie Inst. Pub. 55; 1910, Articles in Amer. Mus. Bull., vol. xxviii; 1911, Revision of the Cotylosauria, Amphibia, and Pisces of the Permian of North Amerca. Carnegie Inst, Pub., nos. 145, 146; 1913, Permocarboniferous vertebrates from New Mexico, idem, no. 181; 1915, Permocarbon- iferous Red Beds of North America, etc., idem, no. 207; 1919, Environment of verte- brate life in the late Paleozoic of North America, idem, no. 283. 2S. W. Williston: (1911.) American Permian vertebrates. Univ. Chicago Press. And various articles, mostly in the Journal of Geology, 1908 to 1918. 404. w.D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY Museum have been studied and compared with the South African faunas by Case, Gregory,* Broom,’ Watson,® and von Huene,’ and important collections from the Texas Permian have been obtained for the Tubingen and Munich museums in Germany. There shall be noted, also, the fine skeleton of the fin-back reptile Dimetrodon, recently mounted in the Na- tional Museum.* The South African Permian has also been vigorously exploited by Broom, Watson, Haughton,® and Van Hoepen’® and large collections made, including many finely preserved skulls and skeletons. This fauna is of peculiar interest as containing apparently the beginnings of the evolution of mammals, birds, and dinosaurs. It is significant that it is regarded as the fauna of an arid or desert region, rather in contrast to the fluviatile or littoral facies represented by the Texas Permian. The third great area for Permian vertebrates, the Dvina River, in Poland, has not, so far as I know, been seriously exploited since the work of Amalitzky, twenty years ago, nor has anything been added to Fritsch’s pioneer work in Bohemia. With all that has been done, we really know very little as yet of the Permian land animals. The period was a most important and critical one in the evolution of land life, for it witnessed the first great expansion of land vertebrates and the origin, probably, of mammals, birds, and the principal orders of reptiles, including dinosaurs. What we know best is the river-delta fauna of the Lower Permian in Texas, a series of plains or desert faune of Upper Permian age in South Africa, and probably a similar facies in Poland; a small Permian swamp fauna in Bohemia, and a few items from other regions. These must represent but a small pro- portion of the variety and scope of land life of the Permian world. How imperfect a picture it gives may be judged by supposing that our knowl- #W. K. Gregory: Various articles in Bull. Amer, Mus. Nat. Hist., 1908 to 1922; 1913, Journal of Morphology. ~ °“R. Broom: (1908-1922.) Numerous articles in Bull. Amer, Mus. Nat. Hist., Proc. Zool. Soe. London, Ann. South African Museum, ete. &p. M:. S. Watson: (1912-1922. Numerous articles in Ann. Mag. Nat. Hist., Proc. Zool. Soc. London, Trans. Roy. Soc. London, Geol. Mag., ete. “F. Von Huene: (1922.) Osteologie des Dicynodon Schidels, Pal. Zeitsch., V, 58-71; 1913, Skull elements of Permian Tetrapoda, Bull. Amer. Mus. Nat. Hist., vol. xxxii, 315- 386 ; 1912-1913, Anatomischer Anzeiger, 42 Bd., s. 98, 472; 43 Bd., s. 389, 519. §C. W. Gilmore: (1919.) A mounted skeleton of Dimetrodon gigas. Proc. U. S. Nat. Mus., vol. 56, pp. 525-539, pls. 70-73. ; °S. H. Haughton: (1915-1918.) Ann. S. African Mus., vol. xii, containing descrip- tions of the paleontological material of the S. African Museum and Geol. Sury. S. Africa; 1919, Review of the reptilian fauna of the Karroo system of South Africa. Trans. Geol. Soc. 8. Afr., vol. xxii, pp. 1-26; 1920, On the genus Ictidopsis. Ann. Durb. Mus., vol. ii, part v; 1921, On the reptilian genera Huparkeria Broom and Mesosuchus Watson. Trans. Roy. Soc. S. Afr., vol. x, pp. 81-88. - 10 Van Hoepen: (1915.) Ann. Transvaal Mus., vol. v, nos. 1, 2. PERMIAN OF TEXAS AND SOUTH AFRICA 405 edge of the modern land vertebrates were similarly limited, to the animals of a South African desert, a Texas delta, and a swamp in central Europe, with a few odds and ends from elsewhere. The zoogeographer would be bold indeed who propounded theories of distribution and migration based on data so limited, and it is to be feared that his conclusions would bear but little relation to the realities. While it is thus necessary to emphasize the limitations of our knowledge, it is but fair to say that it is vastly greater than it was a decade or two ago. The number of genera on record is not so greatly increased, but our systematic and anatomical acquain- tance with the characteristic types is more than doubled. Triassic REPTILES AND AMPHIBIANS OF GERMANY Turning to the age of reptiles, we have in the Triassic the least known chapter, so far as America is concerned, and very little has been added to this chapter in the last decade. What little has been accomplished in this direction is due to the energetic prospecting of Dr. Case and contains promising prospect for the future, as well as a few but very interesting additions to the Triassic faune.1! In Europe, however, the recent dis- coveries of Triassic dinosaurs at Halberstadt and Trossingen in Germany and the discovery of a complete skeleton of a South African Triassic dinosaur have given an adequate basis for the study of these primitive dinosaurs and appreciation of their real relations to the specialized dino- saurs of the later geologic periods. Especially is the discovery by von Huene, in new excavations at Trossingen during the past two seasons, of a series of a dozen or so more or less complete dinosaur skeletons likely to be of great scientific value. Scarcely less important is a large quarry of skulls and skeletons of the great Triassic Labyrinthodont Mastodon- saurus, in the Black Forest region by Professor Wepfner, and the dis- covery of complete skeletons of the very peculiar reptile Placodus, whose teeth were found long ago in Germany and supposed to be the pavement- teeth of a fish allied to the rays. This fine skeleton is being studied by Doctor Drevermann, of the Senckenberg Museum. ; JuRASSIC Dinosaurs oF UTAH AND East AFRICA The two outstanding features of progress in Jurassic land reptiles are the great dinosaur quarry worked by the Carnegie Museum near Jensen, in the Vernal Valley, Utah, and the Tendaguru dinosaur collections from German Hast Africa secured for the Berlin Museum. So far as I can 11 HY; ©. Case: (1922.) Carnegie Inst. Pub. no. 321. 406 wW.D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY judge from the record maps of the Jensen quarry, which I had the privilege of inspecting through the courtesy of Mr. Douglass, the material secured there is greater in quantity and finer in quality than the sum of all that has been obtained hitherto in America. The preparation of this huge collection will be a labor of many years, however it be arranged; but as a result we may look forward confidently to more than doubling our present knowledge of Morrison dinosaurs. The memoirs by Gilmore?” on the carnivorous and armored dinosaurs in the National Museum, chiefly of the Morrison fauna, are of the highest authority and importance and his restudy of the Potomac fauna’ of Lower Cretaceous age shows that it is not the Morrison, as formerly sup- posed, but of decidedly later age. The Tendaguru collection is likewise an immense task in preparation, and when I saw it in Berlin, two years ago, it was far from being completed, after more than ten years’ work. It provides a fairly complete skeletal knowledge of some half-dozen types of dinosaurs** and fragments of a few others, representing a fauna similar in broad lines to the Morrison fauna, nearly similar in its adaptive facies, and approximately of the same age, but inhabiting a different continent, and of the highest importance in giving some really adequate data as to the faunal distribution at that epoch. It is too early yet to draw conclu- sions, but my impression from a superficial review was that the Tenda- guru and Morrison faunas showed a very close adaptive similarity, but were not so closely related as they seemed. It is, fortunately, possible to correlate the Tendaguru dinosaurs exactly through marine faunas. in interdigitating formations. This in turn aids greatly in the correlation of the Morrison fauna, and Schuchert has shown’ that there is strong reason to place it rather at the end of the Jurassic than at the beginning of the Cretaceous. This conclusion is further supported by Gilmore’s. new evidence as to the relations of the Potomac fauna. 2 C, W. Gilmore: (1920.) Osteology of the carnivorous dinosauria in the U. S. Nat. Mus., Bull. 110, U. S. Nat. Mus. ; 1914, Osteology of the armored dinosauria in the U.S. Nat. Mus., Bull. 89, U. S. Nat. Mus.; see also 1909, Osteology of Camptosaurus; 1915, Osteology of Thescelosaurus, and other articles in Proc. U. S. Nat. Mus. 8 C. W. Gilmore: (1921.) Fauna of the Arundel formation of Maryland. Proc. U. 8S. Nat. Mus., vol. lix, pp. 581-594, pls. ex-exiy. 14 \W. Janensch: (1914,) Uebersicht ueber die Wirbelthierfauna der Tendaguru-Schich- ten. Archiy. f. Biontologie, III, 79-140; also pp. 217-261. Ueber Elaphrosaurus u.s. w., Sitzber. Gesell, naturf. Freunde, 1920, pp. 225-235. W. Branca: (1914.) Die Riesengrébe sauropoder Dinosaurier vom Tendaguru, U. s. w.: Archiv. f, Biontologie, vol. iii, pp. 71-78. Pompeckj: (1920-1923.) Personal communications. Kk. Hennig: (1912,.) Am Tendaguru; also various articles in Sitzber. Gesell. naturf. Freunde, 1912-1922. 1% C. Schuchert: (1918.) Bull. Geol. Soc. Am., vol. 29, pp. 245-280. CRETACEOUS DINOSAURS 407 Cretaceous Dinosaurs or ALBERTA, Montana, AND NEw MExiIco It is in the Cretaceous dinosaurs that we can record the greatest prog- ress in the last ten or fifteen years. It is not so long ago that our prac- - tical knowledge of Cretaceous dinosaurian faunas was almost confined to one horizon and to one small area. Substantially, it was the Lance fauna that we knew, and to what extent the fragmentary fossils recorded from other formations and other areas were really distinguishable from those of the Lance was a subject of acrimonious debate. Today we have ex- tended the scope of our geographic knowledge as far as central Alberta to the north and New Mexico to the south, and have been able to distin- euish four well separated geologic zones, each represented by a fauna known from a series of more or less complete skeletons. The earliest of these faunal zones is the Saint Mary’s of the Milk River district in Mon- tana; the second and best known is the Belly River of the Red Deer River in Alberta; the third is the Edmonton of the same region, and the fourth, the Lance of Wyoming and Montana. The great collections secured from the Belly River by the American Museum, the Ottawa, Toronto and Ed- monton museums in Canada, and the Field Museum in Chicago are still being prepared and studied, but it is already evident that it was a sur- prisingly large and varied fauna, of which the Lance was but a remnant, consisting of a few highly specialized survivors.’® Another interesting phase of recent progress in this group is the prob- able difference in faunas widely apart geographically and in different climatic zones. The splendid specimens secured by Charles H. Sternberg in the last two seasons in the San Juan basin of New Mexico appear to _ represent a fauna widely different from any of the three great northern faunas. Their true correlation has yet to be determined by a more exact study of the fauna and stratigraphy, but Mr. Sternberg’s latest. work, performed under heavy handicaps, opens up an important new field for dinosaur collecting and is the last of a long series of important finds made by him during the last fifty years. A fine skull and much of the skeletor of a gigantic Ceratopsian has been secured by the American Museum; other important specimens are still in his hands and in the Upsala Mu- -seum in Sweden. s 1B. Brown: (1912-1917.) A series of papers in Bull. Am. Mus. Nat. Hist. H. &. Osborn: (1917.) Bull. Amer. Mus. Nat. Hist., vol. xxxv, pp. 733-771. L. Lambe: (1914-1920.) Numerous articles in Mem, Geol. Sur. Canada, Ottawa Naturalist, Trans. Roy. Soc. Canada, ete. W. A. Parks: (1919-1922.) Series of articles in Univ. Toronto Studies, Trans. Roy. Soc. Canada, etc. 408 W.D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY THE DINOSAURS NOT A NATURAL ORDER The dinosaurs are now generally recognized as not a natural order of reptiles, but a composite group, including two distinct and rather dis- tantly related orders.‘’ Dinosaurs correspond in a way to pachyderms among mammals, once considered a natural order, but now recognized as an assemblage of animals superficially alike, owing to parallel adapta- tion, but not really related. It is in this sense that the term “dinosaurs’’ should henceforth be used and not as a natural order of reptiles. The two orders are the Saurischia, including Marsh’s two groups of Sauropoda and Theropoda, and the Ornithischia, or Orthopoda, the Predentata of Marsh. The first group includes the gigantic amphibious Dinosaurs, the ereat carnivorous Dinosaurs and their slender, swift-running allies, and the more primitive Triassic dinosaurs. Orthopoda include the Iguano- donts and duck-billed Dinosaurs, the horned Dinosaurs, and the armored Dinosaurs. All these are distinguished by a horny beak or bill and a more bird-like arrangement of the pelvic bones, and have a certain degree of affinity to primitive birds, whereas the Saurischian order has a corre- sponding relation to primitive crocodiles. The fine memoirs by von Huene on various Triassic reptilia,’® by Gilmore’? on the carnivorous and armored dinosaurs, by Osborn on Camarasaurus,?° and a series of de- scriptive papers by Brown, Lambe, Parks, and others are the most impor- tant published contributions in this field. Cenozoic MAMMALS OF WESTERN AMERICA In the field of Tertiary mammals progress has been made at many points. The great series of Tertiary faunas in this country has been im- proved all along the line. Collections from each horizon have been greatly increased; many new or little known species are now represented by complete skulls and skeletons. Careful intensive stratigraphic work in the fossil fields and more exact records of all specimens enable us to define more accurately the limits and succession of faunas and evolution “7H. Von Huene: (1909.) Skizze zu einer Systematik und Stammesgeschichte der Dinosaurier, Centralbl. f. Min. Geol. u. Pal., J’g., 1909, s. 12-22; 1914, Nattirliche Sys- tem der Saurischia, idem, 1914, s. 154-158; 1914, Ueber die Zweistiimmigkeit der Dino- saurier u. s. w., Neues Jahrb., B. B. xxxvii, s. 577-589. 188 Von Huene: (1912-1916.) Series of memoirs and shorter articles chiefly in Paleon- tographica ; 1910-1914, Geol. u. Pal. Abhandl.; 1920-1922, Acta Zoologica; 1909-1922, | Neues Jahrbuch and Centralbl. f. Min. Geol. u. Pal., ete. 19 See page 8, footnote 12. 20H. F. Osborn and C. C. Mook: (1921.) Camarasaurus, Amphicelias and other Sauropods of Cope. Mem. Amer. Mus. Nat. Hist., n.s., vol. iii, pp. 247-387. pls. Ix-Ixxxy. CENOZOIC MAMMALS OF WESTERN AMERICA A409 of phyla. A great advance has been made in the Lower Eocene and Paleocene faunas, the former representing, as I see it, the true beginnings of the Tertiary mammalian succession in this country, while the latter, whatever its precise geologic position may prove to be, is essentially the culmination and close of a Cretaceous mammal fauna whose earlier evo- lutionary stages are wholly unknown to us, either because they inhabited upland areas, where their remains were not preserved, or because they lived in some other region whose Cretaceous land faunas have not yet been discovered.** In the Lower Eocene the most remarkable discovery is the Diatryma, a gigantic ground bird resembling the Phororhachos of the South Amer- ican Miocene, but not related to it and standing apart in a group by ie oa In the Oligocene Sinclair*® has inaugurated an intensive stratigraphic- faunal study of the typical White River badlands that will serve as a foundation for comparison and correlation much more exact and accurate than has been possible hitherto. A remarkable fossil quarry opened by the Denver Museum?** in the Chadron formation of Colorado has yielded already a large series of well preserved skeletons and appears to contain still vast numbers. In the Lower Miocene the great collections of the Carnegie Museum from the Agate fossil quarry have been described by Holland and Peter- son in three fine memoirs,”° and the excellent series of Moropus skeletons obtained by the American Museum from the same quarry provide a com- plete knowledge of this extraordinary animal. Large collections have also been obtained from the Lower Miocene for the Yale, Amherst, and Field museums. The later Miocene and Pliocene faunas are represented in the Snake Creek quarries in Sioux County, Nebraska, which have been worked ne. Matthew: (1913, 1917.) Bull. Amer. Mus. Nat. Hist., vol. xxxii, p. 307 ; vol. XXXvli, pp. 569, 831; 1914, Bull. Geol. Soc. Amer., vol. 25, p. 381; 1921, Am. Jour. Sci., VOle als p. 209: 2 WwW. D. Matthew and W. Granger: (1917.) The skeleton of Diatryma. Bull. Amer. Mus. Nat. Hist., vol. xxxvii, pp. 307-326. 23 W. J. Sinclair: (1921-1922.) Four articles in Proc. Am. Phil. Soc., vols. 1x and 1xi. #4 J. D. Figgins: (1921.) Ann. Rep. Colorado Mus. Nat. Hist., p. 16. *°O. A. Peterson: (1909.) Revision of the Entelodontide. Mem. Carnegie Mus., vol. iv., pp. 41-158, pls. liv-lxii; 1910, Description of new carnivores from the Miocene of western Nebraska, ibid., pp. 205-278, pls. Ixxiv-lxxxv ; 1920, The American Diceratheres, ibid., vol. vii, pp. 399-476, pls. lvii-lxvi. W. J. Holland and O. A. Peterson: (1914.) Osteology of the Chalicotheroidea. Mem. Carnegie Mus., vol. iii, pp. 189-406, pls. xlviii-Ixxvii. 410 W. D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY chiefly by the American Museum.’® While the two great fossil quarries mentioned above contain complete skulls and skeletons of a limited num- ‘ber of large animals—three or four kinds in each—the Snake Creek quarries contain chiefly fragmentary material of a great variety of ani- mals, no less than 50 genera being on my lst at present. They are river- channel pockets and are now known to belong to three distinct faunal zones. Perhaps the most interesting out of a multitude of new forms from these quarries are the upper tooth of an anthropoid primate, Hesperojm- thecus, the first of this group from the American Tertiary, and the com- plete skeleton of Pliohippus, the earhest one-toed stage in the evolution of the horse. Discovery by Troxell of fine skeletons of Pliohippus?* and of a Tertiary type of Mastodon in the Pliocene of South Dakota, and by Gidley of a large Pliocene fauna in Arizona, should also be mentioned. The series of later Tertiary faunas discovered by exploring parties from the University of California, on the Pacific coast and in the Great Basin provinces, are a most important addition, as they are almost wholly new fossil fields.2* The material as yet discovered is largely fragmentary, but a considerable series of faunas has been differentiated. In the Pleistocene the great outstanding discovery is the La Brea asphalt quarries near Los Angeles, remarkable for the numbers, the variety, and the fine preservation of the specimens. The discovery of this unique series makes it possible to describe the more characteristic forms from series of dozens, or even hundreds, of complete skulls with proportionate numbers of skeleton bones.”° PRIMATES AND Man The most widely interesting field of paleontological research is that 72 W. D. Matthew and H. J. Cook: (1909.) Bull. Amer. Mus. Nat. Hist., vol. xxvi, pp. 361-415. W. J. Sinclair: (1915.) Proc. Am. Phil. Soc., vol. liv, pp. 73-95. W. D. Matthew: (1918.) Bull. Amer. Mus. Nat. Hist., vol. xxxviii, pp. 183-229. HH: EF. Osborn: (1918.) Mem. Amer. Mus, Nat: Hist.; n.’s., vol. ip, 2Sineamer Mus. Novitates, no. 37. Ee. Lroxelil: (VOlG,)) Ame Jour: Sci vole xi spp, seo-3400 H. F. Osborn: (1918.) Equide of the Oligocene, Miocene, and Pliocene of North America, iconographic type revision. Mem. Amer. Mus. Nat. Hist,, n. s., vol. ii, p. 162, pls. XXvili-xxx. *° J. C. Merriam and others: (1910-1922.) Uniy. Calif. Geol. Publ., numerous contri- butions. : 2°. S. Daggett: (1918.) Notes on Pleistocene fossils from Rancho La Brea. Los Angeles Co. Mus. Hist., Sci., and Art; Dept. Nat. Sci., Mise. Publ. J. C. Merriam and others: Ut supra. W. D. Matthew: (1913.) Amer. Mus. Jour., vol. xiii, p. 291; 1916, ibid., vol. xvi, pp. 45, 469. PRIMATES AND MAN Ail which deals with the geologic history and evolution of our own race, and in this field there have been a series of discoveries and researches in recent years of the highest importance.*° | First among these I may place the discovery of complete skeletons of Neanderthal man; the skeleton of Chapelle-aux-Saints, so admirably de- scribed by Marcellin Boule ;** the two skeletons of La Ferrassie, soon to be described fully by the same distinguished authority, and a series of less complete but important finds in Germany and other Central Euro- pean States. These discoveries have given a very clear and definite con- cept of the Neanderthal race, as a species clearly distinct from our own, characterized by a series of well defined physical peculiarities, nearer in many particulars to the anthropoid apes, but clearly not a direct ancestor of our own species. The fragmentary skull and jaw found in 1911 near Piltdown, in Sus- sex, likewise represents an extinct species of man, as different from the Neanderthal man as from our own race. Although corresponding in its nearer approach to the anthropoid ‘apes, it probably is not directly ancestral.*° Another remarkable skull, discovered at Broken Hill, in Rhodesia, while not of high antiquity, is regarded as representing a survival of the Neanderthal race in South Africa. The Talgai skull from Queensland, rather doubtfully associated with the Pleistocene fauna of Australia, is considered as representing a proto-Australian type of man. _ The sum of these discoveries is to impress strongly on the mind the probability that our own species is but one out of several human species which lived and flourished and competed one with another during the Pleistocene period; our own species, perhaps through its higher social adaptability, being at last supreme, and sole survivor at the present day. °°'The literature on fossil primates and the evolution of man is very voluminous. A number of excellent critical reviews of the subject by Osborn, Gregory, Boule, Keith, Sollas, Giuffreda-Ruggeri, Leche, Arldt, and others cite and discuss the chief contribu- tions. The most important recent contributions on Tertiary primates are the following: W. K. Gregory: (1920.) Structure and relationships of Notharctus. Mem. Amer. Mus. Nat. Hist., n. s., vol. iit, pp. 49-243, pls. xxiii-lix. H. G. Stehlin: (1912-1916.) Satigethiere der schweiz. Hocens, 7 Teil, Abh. schweiz. paliiont. Ges., vols. xxxviii and xii. G. E. Pilgrim: (1915.) New Siwalik primates and their bearing on the question of the evolution of man and the Anthropoidea. Lec. Geol. Sury. India, vol. xlv, pp. 1-74, pls. i-iv. W. K. Gregory: (1916.) Studies on the evolution of the primates. Bull. Amer. Mus. Nat. Hist., vol. xxxy, 1921, pp. 239-355; Origin and evolution of the human dentition, Baltimore, Williams and Wilkins. 31M. Boule: (1911-1913.) L’/Homme Fossile de Chapelle-aux-Saints, Ann. de Paléont., vols. vi-viii; 1921, Les Hommes Fossiles. 3224. S. Woodward, G. Elliott Smith, Arthur Keith, G. S. Miller, W. P. Pycraft. and others, on VPiltdown skull. 412 W.bD. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY — Yet it appears probable that through crossing and intermixture some of the blood of one or more of these extinct species of man still survives here and there among our own race and may yet be recognizable when the application of mendelism to systematic osteology and paleontology is more fully understood and appled, and also when our collections of the remains of fossil man are so extensive as to admit of such applica- tions. Whatever may be the prospects of getting anywhere along this line, it is quite clearly demonstrated by these recent discoveries that the problem of the ancestry of our race—of the evolution of man—is in reality a much more complex and difficult one than had been assumed either by the exponents or opponents of evolution. It is not one missing link that we have to find, but many. Each of the discoveries I have cited is a “missing lnk’: but we can not be satisfied with merely answering the challenge of the ignorant, and each discovery serves as a spur to further search. A remarkable recent discovery is that of a true anthropoid primate in ~ the Lower Pliocene of this country... While the single upper molar which Osborn has named Hesperopithecus** does not prove the precise affinities of the animal, there is no reasonable doubt in the minds of those who have studied the original specimen that it is one of the higher Anthro- poidea. The discovery of such a type was not wholly unexpected, as the writer and Mr. H. C. Cook, in describing the Snake Creek fauna in 1909, pointed out that certain badly preserved teeth might perhaps be anthro- poid, and that the character of the associated fauna made such a dis- covery reasonably possible. Nevertheless it was not considered likely, as the formation had been diligently and repeatedly prospected in subse- quent years without success. ForEIGN RESEARCHES AND DISCOVERIES, MISCELLANEOUS CONTRIBUTIONS Paleontological research in other parts of the world is much less ad- vanced than in North America and Europe, but, in addition to the few discoveries already mentioned, several other important results of explora- tion have already been secured. In the West Indies a more or less sys- tematic search for fossil vertebrates has been made by the American Museum, the Museum of Comparative Zoology and the National Mu- seum,** and considerable well preserved material secured from the Pleis- 33H. F. Osborn: (1922.) Amer. Mus. Novitates, no. 37. W. K. Gregory and Milo Hellman: (1923.) Amer. Mus. Novitates, no. 53. 3¢W. D. Matthew: (1919.) Proc. Amer. Phil. Soc., vol. lviii, pp. 161-181. H. E. Anthony: (1918.) Mem. Amer. Mus. Nat. Hist., n.s., vol. ii, pp. 331-435, pls. lv-Ixxiv. G. S. Miller: (1916.) Smiths. Miscell. Coll., vol. 66, no. 12; 1922, idem, vol. 74, ==; > no. 3. FOREIGN RESEARCHES AND DISCOVERIES 413 tocene of Cuba and Porto Rico, with fragmentary data on the Pleistocene fauna of Hispaniola and Jamaica. The especial interest of these insular faunas lies in their source and paleogeographic bearings. South America affords an immense field for exploration, but since the death of Florentino Ameghino there is but little progress to record. The explorations begun by the Field Museum will, it is hoped, initiate a new period of advance in our knowledge of the paleontologic history of this continent. In Africa considerable reconnaissance work has been done at various points, but beyond the Tendaguru and Karroo discoveries already noted, the only finds which can be noted here are the Cretaceous dinosaurs dis- covered by Stromer in the Libyan desert.*° These are of quite a remark- able type—Sauropods and a peculiar carnivorous genus—the fauna pos- sibly having descended from the Wealden fauna; but careful comparative study is still needed. 7 In India Doctor Matley has obtained an interesting Cretaceous dino- saur fauna from the Deccan, but only preliminary notices of it have as yet been published.*® The chief advance in Indian paleontology is the admirable stratigraphic and faunal work of Pilgrim in sorting out and correlating the heterogeneous group of faunas hitherto known as the Siwalik fauna.** The splendid collections of these faunas recently se- cured by Barnum Brown for the American Museum deserve special men- tion, as also the discovery of Oligocene and Eocene faunas in Baluchistan ‘and Burma by Cooper, Pilgrim, and Cotter. The gigantic “Balucht- thervum,” of which parts of the skeleton were discovered by Cooper,*® is perhaps the largest known land mammal. Borissiak has reported what seems to be the same animal in Russia, under the name of Indricothe- rium,*® and last summer the American Museum secured a complete skull, nearly five feet in length, in Mongolia.*° The results of the American Museum explorations in Mongolia are probably the most important discovery of the last decade. Central Asia 3°), Stromer: (1914, 1917.) Wirbelthier-Reste der Baharije-Stufe. Abh. Kgl. Bay. Akad. Wiss., xxvii, 3¢ Abh.; xxviii, 3e u. 8e Abh. 36 C, A. Matley: (1922.) Personal communications. B. Brown: (1920-23.) Ab lit. 37qG, H. Pilgrim: (1912.) Vert. Fauna of the Gaj Series. Mem. Geol. Sury. India, vol. iv, no. 2, pp. 1-84, pls. i-xxx ; 1913, Correlation of the Siwaliks with Mammal Hori- zous of Hurope. Rec. Geol. Surv. India, vol. xliii, pp. 264-326, pls. xxvi-xxviii. 38 C, Forster Cooper: (1911.) Paraceratherium bugtiense, a new genus of Rhinoce- rotide. Amer. Mag. Nat. Hist., vol. viii, pp. 711-716, pl. x; 1913, Thaumastotherium. [corr. to Baluchitherium] osborni, a new genus of Perissodactyles. Ibid., vol. xii, pp. 376-381. 39 A, Borissiak: (1915.) Rhinoceros de la Taille dun Mammoth. (Jndricotherium, new genus.) Geological Messenger, vol. 1, pp. 131-134 (Russian text only). 40H. EF. Osborn: (1923.) Amer. Mus. Novitates, no. —. (In press.) 414 w.p. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY has hitherto been a terra incognita to the vertebrate paleontologist, and the finding of rich and extensive fossil fields in the Gobi Desert with Cretaceous, Eocene, Oligocene, and Plocene formations, each yielding considerable faunas and finely preserved specimens, in the first season’s exploration, promises to open up a completely new field in vertebrate paleontology.*t Other fossiliferous horizons will probably be discovered by further explorations, and the history of the land vertebrates of the ereat central Asiatic continent in the Mesozoic and Connanit eras will be placed on record in considerable detail. In the cellars and storage racks of many museums, both in this country and abroad, are important collections of fossil vertebrates acquired many years ago, but never prepared or described. The labor and expense of preparing, studying, and describing this material to make it of use to science is as valuable a contribution as though it were fresh from the field. A considerable part of the work in the National Museum and some in the American Museum has dealt with specimens collected long ago for Marsh and Cope. Recently the Yale Museum has made a vigorous and highly successful campaign to prepare and describe the great fossil col- lections left to that institution by Professor Marsh. A series of articles by Lull, Troxell, and Thorpe in the American Journal of Science testifies to the importance of these additions to our knowledge. Two very valuable and authoritative memoirs by Doctor Teilhard de Chardin should be noted in this connection. In one the classic Cernay- sian fauna at the base of the French Eocene is admirably described and illustrated from the collections in the Paris Museum.*? The relations of this fauna and correlation with the Paleocene faunas of this country are now at last based on adequate data. Of scarcely less importance is Pére Teilhard’s memoir on the carnivora of the Phosphorite fauna, also based on the unrivaled collections in the museum at Paris.*® A third important memoir from the Paris Museum, sumptuously illus- trated and admirably presented by the Director, Marcellin Boule,** de- scribes the fine collections from the Pleistocene of the Tarija Valley, in Bolivia, in the Paris Museum. 41 W. Granger and C, P. Berkey: (1922.) Amer. Mus. Novitates, no. 42; 1923, Ibid., NOS vil #2 P. de Chardin Teilhard: (1921.) Mammiferes de l’Eocene inferiur francais. An- nales de Paléont., x, pp. 171-1767 xi, pp. 1-108, pls. i-viii. 48 Teilhard: (1915.) Les Carnassiers des phosphorites de Quercy. Annales de Palé- ont., ix, pp. 100-195, pls. xii-xx ; 1920, Sur quelques primates des phosphorites de Quercy. Idem, x, pp. 2-20. 44M. Boule and A. Thevenin: (1920.) Mammiferes Fossiles de Tarija, Mission Scien- tifique Crequi-Montfort. Soudier, Paris. MISCELLANEOUS CONTRIBUTIONS Ald Finally, I must not omit to mention a series of great synthetic studies by Osborn, dealing with the later Tertiary Equide, now published ;** the - evolution of the Titanotheres, completed but not yet published, and the evolution of the Proboscidea, still in progress; the practical completion of the splendid monographs on the Santa Cruz Miocene faunas by Scott ;** Winge’s monograph on the Brazilian Edentata ;*7 and a remark- able series of brilliant text-books by Othenio Abel, of Vienna.** There are several other excellent text-books that deserve particular notice, but time will not allow even a mention of them here. CONCLUSIONS AS TO PROGRESS OF RECENT YEARS In the foregoing outline of progress I have been concerned chiefly with discoveries of new material, of new records, because it is the scanty and fragmentary nature of the evidence that is the chief limit to research in vertebrate paleontology and the chief source of error in our conclusions. In the phrase of a French reviewer, vast floods of ink have been spilled on problems of correlation, of phylogeny, of paleogeography, where a few questionable fragments of fossil vertebrates formed the salient points of evidence. When in some instances an adequate fauna was discovered, the problem was promptly and conclusively settled, the flood of ink sud- denly ceased to flow, and deep calm settled over the controversy. _ The fundamental progress achieved appears, therefore, to be measur-— able better in terms of collections than of researches. I do not altogether agree with a distinguished Columbia professor who declared not long ago that paleontologists had no business to reason on or draw conclusions from their specimens, but should content themselves with describing and illustrating them.*® Nevertheless, I do think we should distinguish far more sharply between provisional and tentative conclusions based on scanty and fragmentary data and those which are really proven by ade- quate evidence. SH. F. Osborn: (1918.) Equide of the Oligocene, Miocene, and Pliocene. Amer. Mus. Mem., n. s., vol. ii, pp. 1-217, pls. i-liii. #%W. B. Scott and W. J. Sinclair: (1903-1912.) Rep. Princ. Exped. Patagonia, vols. iv-vi. “A. H. Winge: (1915.) Jordfundne og nulevende Gumlere fra Lagoa Santa. E. Museo Lundii, Kjébenhayn, 1915. 43Q. Abel: (1909.) Ban und Geschichte der Erde; Das Zeitalter der Reptilien here- schaft, Vienna; 1912, Grundziige der Palzobiologie der Wirbelthiere, Schweitzerbart, Stuttgart; 1914, Die Vorzeitlichen Saiigethiere, Fischer, Jena: 1919, Die Stimme der Wirbelthiere, Ver, wiss. Verleger, Berlin-Leipzig; 1920, Lehrbuch der Palxozodlogie, _Fischer, Jena; Methoden der paliobiol. Forschung Urb. u. Schwarzenberg, Berlin-Wien ; 1922, Lebensbilder aus der Tierwelt der Vorzeit, Fischer, Jena. *#T. H. Morgan: (1916.) A critique of the theory of evolution, pp. 24-27. 416 W.D. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY So far as the older and better known fields of vertebrate paleontology are concerned, the progress of the past few years has been in the way of consolidating and confirming what had been tentatively sketched out by earlier workers. In the newer fields we are reaching out and securing the first fruits of exploration—the evidence which will confirm or dis- prove hypotheses and guesses that hitherto have had free rein. SomE TRENDS OF MopERN WorRK In the field of paleogeography I may call attention to three publica- tions treating the subject from diverse or opposite viewpoints: Matthew: Climate and evolution, an essay of some 318 pages; Arldt: Paleogeographie, a treatise of 2 ponderous tomes; Case: Paleogeography of the Permian, a quarto volume of moderate dimensions. It is commonly said that paleogeographic problems should be decided only after marshaling all the evidence in every branch of zoology, past and present, as well as of geology and physiography, that can be brought to bear on it. This is what Doctor Arldt has endeavored to do in his great treatise. I do not hold that view, for it appears to me that unless evidence is thoroughly understood and critically sifted as to its weight and its real significance, it is of no value; and it is obviously impossible for human intelligence to attain a thoroughly critical grasp of so vast a field. On the other hand, the evidence in any one branch, if interpreted rightly, will lead to correct conclusions, and if the conclusions drawn in one field conflict with those drawn in another, it can only be because one or the other is wrongly interpreted. It is not a question of balancing the evidence. If it does not all point one way, then there is some mistake in the interpretations placed on the facts. The problem then les in find- ing out what is the fallacy and in which field it lies; and whether the evi- dence in several fields has been vitiated by the same fallacy. It is only thus that one can arrive at true conclusions in problems of this sort. To attempt to decide them by the balance of evidence, as one would settle a problem in taxonomy, is more likely to put one wrong than right. Doctor Case’s volume is of interest as placing a novel and much broader significance on the term paleogeography, making it almost equivalent to what might be called paleoecology. He has little to say in this volume as to the question of continental outlines, so commonly discussed as though it were the whole of the subject, but is concerned chiefly with the habitat of the animals, its nature and changes, and the physical geography of Permian North America. SOME TRENDS OF MODERN WORK nS There has been for the past two decades a tendency among vertebratists to keep more closely in touch with stratigraphic geology. ‘The compara- tive anatomist, especially in setting forth the evolution and specialization of structures, tends to arrange his material in categories and sequences - that show the evolution of structures and organs, but are of course struc- tural and not genetic sequences, as the animals are all contemporaneous. The paleontologist, however, is dealing with true genetic sequences, exact or approximate ; with the evolution of species and genera of animals, not merely with illustrations of how certain structures may have evolved. The time relations of his specimens must be known exactly and carefully considered. This has been always to the forefront in invertebrate pale- ontology. Much of the early research in vertebrate paleontology, how- ever, was by men who were comparative anatomists rather than geol- ogists, and the fragmentary material with which they had to deal made a thorough practical acquaintance with comparative osteology the first essential to its correct identification and study. It is no less important today on account of the complex structure of the vertebrate skeleton ; but an inevitable consequence is a certain tendency to take the anatomist’s viewpoint and study too much the evolution of structures and not enough the actual sequence in time of the animals themselves. The corrective of this tendency is a closer union with the geologists, and in the founding of our Society it was hoped and expected that this would result. So far as I can see, the course of American paleontology in the past two decades has demonstrated the wisdom of this action. The exact records of speci- mens and more careful stratigraphic studies have enabled us to define horizons and differentiate faunas in much more precise and correct detail ; and, with the far larger collections and more complete specimens, the records are adequate to trace in many cases the evolution of species and not merely of structures. The earlier writers on evolution did not at- tempt this. Gaudry and Heckel, Riitimeyer and Kowalewsky, Huxley and Cope, demonstrated from the paleontologic record the evolution of structure. Depéret and Schlosser, Osborn and Scott, and many others have perceived and pointed out this weakness in our evidence and have attempted to trace the true phyla. But it is only recently that the evi- dence has been adequate to place such attempts on a really sound and permanent basis, and indeed most of our work in this line is still tenta- tive and provisional. Nevertheless, we may expect to see these beginnings extended year by year, and the old structural phylogenies elaborated by the previous generation, and scoffed at with some justice by critics as a vast “schwindelbau,” replaced by the veritable records of the phyletic XXVITI—BULL. Grou. Soc. Am., Vou. 34, 1922 418 Ww.bD. MATTHEW—PROGRESS IN VERTEBRATE PALEONTOLOGY history of races of animals. In so far as this is accomplished, Professor Morgan’s strictures on paleontological evolution,”® which are aimed really at the old methods, not at our modern standards, will be no longer justi- fied. Paleontologists, with the facts before them as to what actually did take place in the evolution of a race of animals, may claim the right to reason and draw conclusions from these data as to the methods and causes of the transmutation of species. On the anatomical side of paleontology, the far greater completeness of our material in recent years has stimulated comparative researches of high quality, apparent in many of the memoirs I have cited and in a series of memoirs by Gregory, Watson, Broom, Williston, Case, and many others. Taxonomic researches and revisions have by no means been neglected, but I can mention only one of the many completed or in progress, the revision by Miller and Gidley of the super-generic groups of rodents, in which, for the first time, the fossil representatives of this order have received adequate treatment in a comprehensive revision. In looking over the apparent trend of recent advances I am impressed with the honest and conscientious endeavor everywhere apparent to pro- vide a broader and more secure foundation of evidence for our researches by much more extensive collections, more complete specimens, and more exact records. We have tried to get into closer touch with stratigraphic geology on one side, with comparative anatomy and zoology on the other. We have, on the whole, I think, kept fairly clear, considering the great increase in our collections, of the temptation to multiply species corre- spondingly, the besetting sin of the systematist; and, although the Men- delan school of zoologists will have naught to do with us, we have suc- ceeded, I think, in making very good use of the data and viewpoints that they have emphasized and incorporating them satisfactorily into our own scheme of things. 5° See footnote 49. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34. PP. 419-430 SEPTEMBER 30, 1923 . SOME STRUCTURAL FEATURES OF THE PLAINS AREA OF ALBERTA CAUSED BY PLEISTOCENE GLACIATION? BY OLIVER B. HOPKINS (Read before the Society December 30, 1922) CONTENTS Page TMGEOMUCHION... =... 3! « ee oa Lumera gy aia d eee ETE Satta, GE a tree Muah eh apa eon Ne an la wie eG 419 REE tester ted Te a es TRES OM NING sl, Garces, ict gaye "a, tss-ae, oo ote acallai See mailece wie joie! Shshlea elle on: Bai JS vAlahe es 420 IMM OMMMISN UNI Staten aide eet oS so eet tran ah etcia tgs oe a Geeta dae Bs secu Sie ae hie Re atten Shh a PE aa ae 421 Pyidence or Surticral nature of disturbance... 0. 0c. ne ie ce we lee wee 424 irioenece woke COEUISLINE: TOLCE. S.-..0% owx isle ules o won eles slew sore Geet oe ieee ses ie 426 Development of complex structure by movement of ice-sheet............. 428 OTE ZEN? 5p oleh a GSE Sie tond GeSRE eRe ceo saa? ar a a sea re 429 INTRODUCTION Some anomalous structural features in the Great Plains area of Alberta have been known for a long time, but in recent years they have come into considerable prominence because of the prospect of commercial oil pools being associated with them. The study of one of the most conspicuous of these supposed uplifts, together with the result of wells recently drilled in the vicinity, indicate fairly conclusively that there has been no uplift- ing of the formations in the area, and that the abnormally steep dips and local folds and faults are the result of the thrust of the great ice-sheet which moved southward over this area in Pleistocene time. The object of this paper is to demonstrate, if possible, two points, namely : (1) That the intense deformation of the beds observed at Mud Buttes and similar localities is entirely superficial and without deep-seated sig- nificance and in no way connected genetically with tectonic disturbance of the region. (2) That the abnormal surficial disturbance of the strata was caused by the movement of the continental ice-sheet against conspicuous pre- glacial hills. 1 Manuscript received by the Secretary of the Society January 15, 1923. (419) 420 oOo. B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA The writer acknowledges with pleasure the cooperation of Dr. J. S. Stewart in the development of the ideas herein set forth and his help in the preparation of this paper. DESCRIPTION OF REGION The area in which the abnormal structures are found is in the plains region of east-central Alberta (see accompanying sketch, figure 1). Ab- SKETCH DEEP WEELES EAST-CENTRAL. ALBERTA WESTERN SAS KATCI {EWAN Gemere eras ae MUDDY LAKE W ~ Bare Benton etit * Mackion Tom Lumes toc -£>% JSaiwador SS SS ee ered FUSILIER WELL Se es ee ae +4708 > as = —— FIGURE 1.—Deev Wells of east-central Alberta, western Saskatchewan normal dips are found at many places in that region; but the complex structures, to be described later on, are found in two principal groups of hills, namely Tit Hills and Mud Buttes. The former are located 10 miles south of Czar and the latter 9 miles south of Monitor. In most of the hills of the region abnormal dips are in evidence, due either to DESCRIPTION OF REGION 421 slumping or other causes, whereas exposures in the valley generally show the strata to be flat-lying, in conformity with the general dip of the region. In this part of the Great Plains are found here and there groups of hills, such as those named above, and other similar ones, such as Misty Hills, Neutral Hills, etcetera, which rise a few hundred feet above the generally flat, treeless, but well grassed plain. Cretaceous formations underlie the surficial deposits of the plain to depths of 2,000 to 3,000 feet. The outcropping strata in the immediate vicinity of the hills, here described as showing abnormal deformation, Ficurre 2.—General View of Tit Hills belong in every case to the Belly River formation. With the exception of the abnormal dips in the few hills referred to above, all the evidence - points to uniform but gently dipping beds over the whole area; but as the formations are soft, exposures poor, and the width of the outcrop great, it is difficult to work out detailed structure. Mvp Buttes As the conclusions herein set forth were derived largely from a brief study of the Mud Buttes, it is proper that they should be described in some detail. . The Mud Buttes are situated 9 miles south of Monitor, a station on a branch of the Canadian Pacific Railway, and cover parts of sections 19 and 20, township 33 north, range 4, west of fourth meridian. 422 0. B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA They form a compact group of hills about one mile long by one-half mile broad which rise a few hundred feet above the plains. Their su- perior altitude has caused them to be eroded into typical bad-land topog- raphy, exposing admirably the strata of which they are composed. The strata belong to the Pale Beds, the upper division of the Belly River formation, of Middle Montana age, and consist of a series of inter- bedded sands, sandy clays, and lgnitic clays with ironstone bands. The beds show a prevailing dip of about 30 degrees to the north-north- east and a general strike varying from north 80 to 110 degrees east. At many places the strike and dip is modified by slumping, which adds to the apparent intensity of the deformation. FIGURE 3.—-Sketch Map showing geologic Structure of Mud Buttes Sections 19 and 20, township 33 north, range 4 west of 4th meridian, Alberta. The same series of beds are repeated several times by the miniature folds and thrust faults which run through the hills in a general east-west direction. Sufficient work has not been done to map the details of the structure accurately, and as figures 5-10 illustrate the intensity of the faulting, folding, and crumpling I shall not attempt to describe it in detail. That the same series of beds are duplicated is obvious from a study of the outcrops and from the fact that only the upper division of the Belly River formation is involved, as stated above. A noteworthy feature of this supposed uplift is the general absence of dips in any direction other than to the north. The fact that the hills show only prevailing north dips caused them to be considered the north limb of an uplift; but there are no complimentary east, south, or west MUD BUTTES 423 FIGURE 4.—View of Mud Buttes from the Southeast Showing small overthrust folds. 424 O.B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA dips. This fact in itself makes the shape and extent of the supposed uplift conjectural. EVIDENCE OF SURFICIAL NATURE OF DISTURBANCE There are many lines of evidence enumerated below, which lead to the conclusion that the intense disturbance of the strata in this area is sur- ficial in character; in fact, the only evidence of uplift is the presence, locally, of steeply dipping, faulted, and folded strata. Such evidence is conclusive so far as it does not run counter to all other evidence, as it appears to do in this case. The supposed uplifts are located in every case on the outcrop of the Belly River formation, and in no case do they cause either narrowing or | widening of the outcrop, nor do they bring to the surface strata older than those normal to the area. Furthermore, several subdivisions of the Belly River formation are recognized in this area and are found appar- ently in their normal sequence, in a regular descending series eastward and ascending series westward, thus indicating the absence of folds of appreciable size, such as we should expect from the intensity of the deformation displayed at Mud Buttes. If the observed dips were other than surficial, certainly the normal distribution of formations would be disturbed, as a 30-degree dip has been observed over a distance of one- half mile at Mud Buttes. If this dip should continue without duplica- tion of strata for 114 miles, the entire Cretaceous section would be ex- posed, whereas only the upper division of the Belly River is found. Turning now to the structural information from well logs; the best line of evidence is derived from four wells, which include the Muddy Lake, Fusilier, West Regent, and Misty Hills wells. These are roughly on a line from northeast to southwest, down the dip, and the last two are in immediate proximity to Mud Buttes. The base of the Colorado Shale, which is the most reliable datum pres- ent, shows a dip of 5 feet per mile from the Muddy Lake to the Fusilier well, and 614 feet per mile from the Fusilier to the Misty Hills well. Thus the Misty Hills well, which is on one of the supposed uplifts, instead of being structurally higher is in reality as low as would be expected from the regional structure of the area. Furthermore, from the West Regent well, which is on the north side of the supposed uplift, to the Misty Hills well, a distance of 11 miles, there is a dip to the south of 7 feet per mile, which is also normal for the area. The significance of this is obvious from the fact that the Mud Buttes are half way between these wells. Thus, from the evidence available, we are led to the conclusion that EVIDENCE OF SURFICIAL NATURE OF DISTURBANCE 425 FIGURE 6.—Olose View of Mud Buttes Showing intense folding and faulting. FIGURE 7.—Close View of Mud Buttes Showing intense folding and faulting. A?6 oO. B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA there is no uplift at Mud Buttes, as has been supposed by many geologists who have visited the area. Regarding Tit Hills, the other center of supposed uplift, the evidence is similar and equally convincing that no local uplift is present. A well was drilled on the north side of these hills, on the supposed uplift, and instead of finding a structural high found the formations at their normal depth. Thus the base of the Colorado found at 154 feet above sealevel at Fabyan, 40 miles to the north, is found here at 233 feet below sealevel, showing the normal southward dip of 914 feet per mile. The larger group of hills to the south of Mud Buttes, named Misty Hills, have not been deformed to the same extent as Mud Buttes, but this may be explained readily as due to the greater resistance of their much larger mass. Considerable dislocation of the normal attitude of the strata is found in these hills, however, and this is attributed in part to the movement of the ice-sheet and in part to slumping. The nature of the disturbance of the beds at Mud Buttes and Tit Hills is not such as could be attributed to the development of gentle folds. The intensity of the folding and faulting, if due to deep-seated forces, could only have resulted from (a) tremendous local uplift, (>) or from intense lateral compression, such as produces great overthrust faults. We have already seen that there is no intense local uplift present, as no old rocks are brought to the surface. Furthermore, there has been no regional movement that could have produced these local deformations. The region is singularly devoid of structural disturbance; the only fea- ture of note which appears to disturb the generally flat-lying and gently dipping beds is a shght change in strike from southwest to south or slightly east of south. ‘This, however, is a broad regional feature which can best be explained as due to warping of the former Cretaceous basin along broad lines. Such a slight amount of differential movement, neces- sary to produce the observed change in strike of these flat-lying beds, could not be called upon to explain such intense local disturbances as found here. Thus the distribution of the foranntactue and the broad consideration of the structure, together with the confirmative evidence from deep borings, lead to the conclusion that the disturbance of the strata is of surficial origin. EVIDENCE OF THRUSTING ForCE The similarity of the structure observed in Mud Buttes to that devel- oped in the foothills belt of Alberta, where the limestone ranges of the EVIDENCE OF THRUSTING FORCE 42 FIGURE 8.—Near View of Mud Buttes Showing complicated detailed structure. FIGURE 9.—Near View of Mud Buttes Showing complicated detailed structure. 428 0. B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA Rockies have overridden the Cretaceous, leads naturally to the supposi- tion of similar causes, but operating on a smaller scale. The similarity is quite marked in the following respects: (a) The disturbance of the formations leading to crushing and crum- pling is more intense on the north side of the hills—that is, on the side from which the thrust was applied. : (b) Folds and faults have been developed at right angles to the direc- tion of the thrust—that is, in a general east-west direction. (c) Thrust faults are the dominant structural features, and such anti- clines as are formed are commonly thrust faulted on their southern limb. (d) Thrust faulting has led to the formation of small blocks which dip generally to the north—that is, in the direction from which the thrust was applied. The analogy is so close that we are forced to look for a thrusting force from the north-northeast, whether it is granted that the deformation is surficial or not. | DEVELOPMENT OF COMPLEX STRUCTURE BY MOVEMENT OF ICE-SHEET If the surficial nature of the disturbance is granted, the surficial nature of the force and its direction leads naturally to the assumption that the thrusting force was the great ice-sheet because it was the only competent force. It might be questioned whether the movement of the ice-sheet was a competent force, as it is not usually conceded such power for per- forming work. However, it is unquestionably the most potent surficial force and probably the only one that can be called upon to explain such results. The hills present in the area today were undoubtedly hills in Pleisto- cene time and formed obstacles to the forward movement of the ice-sheet. The ice piled up against and finally overrode the hills. As the pile of ice increased, the pressure against the north side of the hills probably caused the soft shaly strata to buckle and fold, accompanied by movement along some horizontal bed of soft material, thus developing a horizontal thrust plane. As this continued inward toward the center of the hill, a sub- sidiary fault would develop along the small buckles, thus causing the thrust faults observed at Mud Buttes (see figure 10). When the blocks thus formed had been rotated to such a position that the pressure was more or less at right angles to the bedding, instead of parallel to it, the strata would be capable of transmitting the thrust, causing the extension of the flat thrust plane and the further development of other blocks. In this way the complex structure observed was probably developed. DEVELOPMENT OF COMPLEX. STRUCTURE BY ICE-SHEET 429 The absence of marked infolding of glacial material is due to the fact that glacial deposits are largely found in the valley and that the hills were probably truncated by the movement of the ice-sheet across their tops. Thus the hills as seen today may be only the roots of former hills _ of which the strata comprising them have been jumbled up and their tops cut off by the planing action of the ice-sheet. SS SS SSS—) FiGuRE 10.—Development of Structure of Mud Buttes Sketches a, b, c, d represent hypothetical stages in the development of the compiex structure of Mud Buttes SUMMARY Briefly stated, then, there is a belt in eastern Alberta where the upper member of the Belly River formation outcrops, and in some of the hilly portions of this belt the soft incompetent strata are intensely folded with- out bringing to the surface the older more deeply buried beds. There is no disturbed region outside of this belt from which stresses, such as are indicated by the folding at Mud Buttes, might have been transmitted. There is no apparent change in the width of the outcrop of the Belly River formation in the vicinity of these intensely folded areas such as might be expected to result from such folding. Nowhere in eastern Alberta do the river sections exhibit or indicate folding, but wherever the dip is determinable the strata are nearly hori- zontal, dipping at the rate of only a few feet per mile toward the south- west. Corroborative evidence of this gentle dip toward the southwest is found in the records of deep wells drilled in the region. 430 oO. B. HOPKINS—STRUCTURAL FEATURES OF PLAINS OF ALBERTA The conclusion seems justified that the folding and faulting at Mud Buttes and similar localities is surficial and does not affect the underlying formations. What force could produce intense deformation of surface beds without affecting the underlying ones? Slumping will not account for it, as the folding shows too much regularity in strike and dip and involves the entire mass of the hills. The only competent force that can be called upon to explain surficial disturbance of the strata is the continental ice- sheet which moved southward over these hills in Pleistocene time. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 431-448 SEPTEMBER 30, 1923 - FUSION OF SEDIMENTARY ROCKS IN DRILL-HOLES? BY N. L. BOWEN AND M. AUROUSSEAU (Presented before the Society December 30, 1922 CONTENTS : Page RMN OIE TOT RS htt Stoo. ead; Yale yoralccpehse rarer as! a vare Soeilanes oe speed ne es Sennen cum ina raked, a Hh Mactoscepic characters ofthe core material. cS. 3. e so eae see eee 35 Chemical character of the core material........ ep nen a MSs ny Steir WE Sse, 5 435 LECT TAS ET ESTO RSMY CI B10 IS) 10 0 er eee eg i a arf eS Aarie een kt 436 ESa MEMO. TEIEST ONE Liz 5. 570 ao0 ws esie at 6 clea Bunce Sih Beehofeee claps ti ohatare ee? Geen 4c. ole ABT hanes effected in the steel of fae core barrel..: oo... 2. ek eee 438 tmearomvar weak by {TiehOn.. 2.2% ose ooo 3 ke ews ee see es es 39 Garearoem “Meyer 6’ well of the Union Oil-Company..-. <<... 0.022... ... 440 Syocmane position of the fused samples... .. fo. secede Sede pe ce oe 442, General considerations regarding the fusibility of cores................. ja- Refusion of sediments as a factor in magma genesiS.......... ceccescees ais 5 SEDEEL EALRT Se sy STE Oa eg a ge a ard 2 ee rr a 447 be LS EGS DED 5 EI IAS Neos Sr Si 9 A Re aE eS cs ea ed le 447 INTRODUCTION In drilling for oil the taking of core samples of the beds penetrated is becoming a common practice. With the rotary drill the rock cuttings are ordinarily swept out by a vigorous forced circulation of sludge in the hole, but it has been found possible in many cases to modify the pro- cedure in such a way that a core of moderate length can be obtained. The usual bit is dispensed with and a length of ordinary drill pipe with teeth cut at the end is substituted. This is rotated at the bottom of the hole, and under favorable circumstances it cuts through the rock and furnishes a cylindrical core. The presence of the core prevents the circu- lation of water to the bottom of the hole; indeed, a wooden plug is sometimes inserted in the top of the core barrel to guarantee this condi- tion. With the free circulation of water thus cut off, the heat produced by the friction of boring may be sufficiently localized to raise the temper- ature of the rock very considerably ; in fact, it is not uncommon to obtain 1 Manuscript received by the Secretary of the Society February 15, 1923. 4132 BOWEN AND AUROUSSEAU: Oore Barrel from Montezuma Well Number 1 ip Showing deformation and twisting of the tip. part was filled for a length of about one foot with a dark slag, which shows dark in the sectioned part, but has been removed from the tip for laboratory study. FIGuRE The lower immediately above the tip to show nature of contests. It is sectioned FUSION OF SEDIMENTARY ROCKS more or less complete fusion of the rock. Fused cores have been examined by competent geologists and pro- nounced the result of fusion of the sediment- ary rock in place,? but in spite of this fact some operators are unwilling to accept their findings and believe that natural igneous material was en- countered. A particular good ex- ample of a fused core was obtained in a well being drilled in Califor- nia under the _ super- vision of Prof. Bailey Willis. This, together with another not so well preserved, was sent by him to this Laboratory, and the results of our examination are set forth in the present paper. We are greatly indebted to Professor Willis for the opportunity of studying this material and for in- formation regarding the conditions under which it was formed. The better core comes from a hole near Suisun, California, known as Montezuma well number 1. At a depth of 4,350 7A. F. Rogers: Seventh Annual Report, State Oil and Gas Supervisor, vol. 7, no. 9, California State Mining Bureau, March, 1922, p. 6; C. S. Ross, Bull. Am. Assoc. Petro- leum Geol., vol. 6, 1922, pp. 372-374. INTRODUCTION 433 feet, when in Eocene shale, so called, a core was taken after the method outlined above. The driller reports that the barrel was rotated at a speed of about 25 revolutions per minute and estimates the pressure resting on it at about 20 tons. The first 214 feet of the core were pene- . trated in 20 minutes, but the rest, amounting to one foot, went very slowly and required about 40 minutes. It may be safely assumed that this latter period corresponds with that during which significant heating and softening of the drill occurred. When the core barrel was raised it was found that the end of it had plainly been softened and twisted, and that it was filled for a length of about one foot by a dark, slaggy plug. Above this came the unaltered sediment, locally much twisted and contorted by the motion of the drill, but elsewhere still retaining its banding little disturbed. The tip of the core barrel and the part immediately above it, sectioned so as to exhibit the nature of its contents, are shown in figure 1. Microscopic CHARACTERS OF THE CoRE MATERIAL The excellent state of preservation of the core makes it possible to arrive at some definite conclusions regarding the changes that have oc- curred. ‘The unchanged sediment is banded in alternating layers of coarse and fine material, with the coarse markedly predominating. The coarser layers are made up of arkose and the finer layers are more defi- nitely shalelike. Under the microscope the arkose is found to consist largely of angular to subangular grains of the following minerals in order of abundance: quartz, plagioclase (mainly Ab,An,), and microcline, with minor amounts of biotite, muscovite, and indefinite claylike matter. The shaly layers are made up largely of finer grains of the same minerals with a moderately greater amount of the claylike matter. The rather friable and little compacted material of the unchanged sedi- ment gives place abruptly to the dark slaggy mass of the fused portion. The only change to be noted as the fused part is approached is that a few platy crystals of tridymite have been formed in the arkose. The characteristic feature of the fused portion (see figure 2) is the presence in it of glass. In the glass are embedded the undissolved grains of the original minerals, which may vary in amount from about one-half of the whole mass to a very small fraction of it. In places, then, the rock has been converted almost completely to glass, in which case the mass is hght colored and of a pale yellow in thin section. As the extent of fusion diminishes, the glass becomes darker and more nearly opaque. The refractive index of the glass varies somewhat, but is never far from XXIX—BULL. GEOL. Soc. Am., VOL. 34, 1922 434 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS 1.53. Such selective action during fusion as is in evidence is mainly connected with the size of grain rather than with the nature of the ma- terial. The residual undissolved grains are the larger grains of practi- cally all the minerals present, and the ready getting together of the finer grains to effect mutual fluxing has evidently been the important factor in facilitating fusion. Quartz and plagioclase are the more persistent, FiGuRE 2,—Thin-section of fused Core, Montezuma Well Numter i Crossed nicols. The dark areas are glass, the bright patches undissolved grains of quartz and plagioclase. 'Twinned plagioclase at center. as they are the larger grains, but the quartz is apparently not more per- sistent than plagioclase. It is not impossible, however, that the very fine so called clayey matter may be intrinsically more fusible. Occasional small fragments of metallic iron from the pipe are to be found in the glass. MICROSCOPIC CHARACTERS OF CORE MATERIAL A385 In most of the glass there is a moderate amount of recrystallization. The separated crystals are not definitely identifiable, but appear to con- sist largely of minute needles of sillimanite. Close to the iron pipe there is a fairly conspicuous development of fayalite in small but definitely - determinable grains of very high birefringence and minimum refractive index about 1.83. : CHEMICAL CHARACTER OF THE CorE MATERIAL The general appearance of the core and the microscopic characters of its material leave little room for question as to the fusion of sediment in place. Any lingering doubt is completely dispelled by a chemical study of the fused and unfused portions. Samples for analysis were obtained by selecting representative frag- ments of the broken part of the fused plug and by taking a chisel cut about a foot long in the unfused material immediately above the plug. The ordinary methods of silicate analysis, as advocated by Hillebrand and Washington, were employed, except that in the determination of metallic iron in the fused portions recourse was had to the method given -by Treadwell and Hall, which involves treatment of the sample with mercuric chloride solution and subsequent titration of the dissolved iron in the presence of manganous sulphate.* The determination of metallic iron in the presence of iron oxides can not be carried out with great precision by any method adaptable to our problem. The results are to be regarded as close approximations. In the presence of metallic iron the determination of ferrous iron by Pratt’s method is unreliable. The core contains only a slight amount of metallic iron, and therefore the oxide determinations, both by Pratt’s method and as total iron oxides, were in very close accord. A series of determinations was made and the figures given are the average of these determinations. As the average values for FeO plus metallic iron considered as FeO and total oxides considered as FeO differed only by 0.03 per cent and as the fusion took place in the presence of metallic iron, it must be considered that there is no ferric iron present. Moreover, we have been unable to detect magnetite in the fused product. At the same time it can not be proved by chemical means that ferric iron is entirely absent. In the determination of water lost at 110 degrees from the unfused sediment the weighing had to be carried out with despatch. The powder is hygroscopic and regains a large proportoin of this water on the balance pan. 3'Treadwell and Hall: Analytical Chemistry, vol. ii, 5th ed., 1919, p..611. 456 af 2 3 + 5 6 7 8 9 Percentage Differences differences Unfused Fused Fused Unfused Fused a _— _ — SIO, entices we oe GP72 64:17 . 64.40 “6GL16 “Gh1G S22. 2h ee eee ATs, abcess 17.05. 37.42 VAS" T7070 16:48 .y..2 oe PEO Sok Seen 1.48 none none 1.48 + none »-...45- 48 eee 100 HeOky Jaros 2 wale 2-64. 0:02 22 e- eeeeeee EO Seeaeats 2.00." 0.24. O524 © 2:00 0.2383. ee eee 88 HO een wens 3.47. 0.02" 0.02" 73248. 0:02. 2 orto eee 99 COO oe vette eae 0.65 none none 0.65~ none’. 2024 02655 eee 100 diy @ Pagar henna ah ok 0:58. 0.62 (0.62 90758. (0.59) OL een fa 8 eee eas See 0.21 0.28. -0.28 - 0.21. 0.27 0:06 >... oie ys a Owen cree 0.14. .0:06° 0.06.~ 0.14 ~ 0:06... 222-0308 eee oT CEO Reo Nasties trace trace trace tracetrace ..:. <<...) 29. Mai@s ocho ccto rs 0.06 0.07 0.07 - 0:06 0.07 0.01L--.. 2.) Ga Bass actos 0.07. 0.08 | 0.08 -0.0T -~O:0T > 2.26) a ee DURES sta. etens 99.98 100.12 100.02 100.05 95.92 3.98 8.11 Less 0O........: .05 . 02 . 02 .05 | a Aare .03 SUM ~ 470: Sheree 99.93 100.10 100.00 100.00 95.90 .... 8.08 95.90 3.98 Percentage change on fusion........ —4.10 .... ....—4.10 BOWEN AND AUROUSSEAU—-FUSION OF SEDIMENTARY ROCKS TABLE I.—Chemical Analyses of Core from Montezuma Well 1. Unfused Eocene (Tejon) sediment from core taken in Montezuma well, near Suisun, Solano County, California. M. Aurousseau, analyst. 2. Fused portion of core. M. Aurousseau, analyst. 3. Fused portion of core from (2) by deducting metallic iron and reducing to 100. 4. (1) calculated to 100. 5. Amount of each oxide associated with 61.76 grams of SiO, in fused ma- terial calculated from (3). 6. Positive differences. mal . Negative differences. . Positive percentage differences from amounts in original sediment. 9. Negative percentage differences from amounts in original sediment. CHEMICAL EFFECTS OF FUSION The analyses of the fused and unfused portions show very remarkable correspondence.: There can be no doubt of the identity of the fused plug with the unfused sediment immediately overlying it, nor can there be CHEMICAL EFFECTS OF FUSION Ee aie any doubt that the samples were representative to an unexpected degree. Our results, therefore, furnish a very trustworthy basis for a discussion of the chemical effects of fusion. In order to compare the analyses, we have reduced them to a common - silica basis by recalculating the analysis of the fused portion. Columns 4 and 5, Table I, therefore state the amounts of each oxide associated with 61.76 grams Si0, in both fused and unfused. Columns 6 and 7 show differences and columns 8 and 9 express these as percentages of the amounts present in the original unfused sediment. In these last two columns figures in brackets represent original differences between the fused and unfused material. For constituents present in accurately de- terminable amounts the differences range from 2 per cent to 8 per cent. Figures not in brackets represent the effects of fusion, and range from 57 per cent to 137 per cent. The differences in K,O, TiO,, P,O,, MnO, and possibly Al,O, are within the limits of analytical error. Those in MgO, CaO, and perhaps Al,O, represent actual differences between the two samples. A calculation from these two columns shows that the iron pipe has contributed 1.78 grams of iron (or 2.29 grams stated as FeO) to 100 grams of the original material, on fusion. In the oxidation of this additional iron to FeO and in the concomitant reduction of the original amount of Fe,O, to FeO, there has been a change in oxygen content of +0.35 gram. This oxygen may be assumed to have come from the decomposition of water by metallic iron at the elevated tem- perature. All the CO,, practically all the water, and about one-half of the sul- phur have been driven off during the fusion. Only 0.26 per cent of water has actually remained in the fused product—a fact to which refer- ence will be made later. The remaining percentage differences are to be attributed to actual variation, in reality very slight, in the nature of the material in the sedimentary column penetrated. TEMPERATURE OF FUSION We have made tests on the material of the core to determine the tem- perature required for fusion. When heated in air the rock powder is changed to a brick-red frit in which the iron has evidently been largely oxidized to the ferric state, and tests carried out under these conditions would give little indication of the temperature of fusion under the con- ditions of drilling. The tests were therefore made in a current of CO, and steam after a method devised by E. S. Shepherd, of this Laboratory, who has found that in such an atmosphere the state of oxidation of the 438 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS iron remains unchanged in silicate substances of moderate iron content. When the material was heated in this way and the product examined under the microscope, it was found that at 1,050 degrees centigrade only a slight sintering was obtained, at 1,100 degrees centigrade a consider- able amount of glass was formed, and at 1,150 degrees centigrade a proportion of glass was formed in one hour about equivalent to that formed in the fused part of the core. A temperature nearly, if not quite, as high as the last (1,150 degrees centigrade) must have been attained in the drill-hole in order to produce the results actually found. It is true that the fusion of the core tock place under a head of water sufh- cient to give a pressure of about 150 atmospheres, but that this was not adequate to bring about significant solution of water in the silicate melt is plainly indicated by the analysis of the fused core, which shows only 0.26 per cent water, an amount of the order of magnitude to be expected from laboratory experience of the effects of such moderate pressures. For such a minute amount of water one can, with little fear of significant error, calculate, from the ordinary law of freezing-point lowering, its effect on the fusion temperature, and it will be found that a lowering of 15 degrees to 20 degrees centigrade is to be expected. Such a small effect has no importance in the present connection; nor can it be suc- cessfully maintained that the amount of water now present in the fusion is no indication of the amount formerly present. The core was very rapidly cooled, immediately on cessation of drilling, to a temperature at which the glass was rigid and in such a condition that no volatile matter could escape from it. Indeed, this cooling took place under the same head of water as that under which the fusion occurred; so that there would be no tendency toward the escape of water from the melt. ‘Only after cooling was the core slowly raised to the surface. The conditions are the reverse of those experienced by a natural water- bearing lava, which, when poured out on the surface, maintains its high temperature for a long period, relatively speaking, but has the pressure exerted on it suddenly reduced—a combination decidedly favorable to ‘the escape of volatile matter. There is no avoiding the conclusion that the small amount of water present in the fused core represents all of that component that it was able to retain at the temperature and pressure existent during fusion. A temperature very nearly equal to that required for dry fusion must therefore have obtained. CHANGES EFFECTED IN THE STEEL OF THE CoRE BARREL This conclusion as to the high temperature that was attained is com- pletely confirmed by a study of the changes that have taken place in the CHANGES IN STEEL OF CORE BARREL 439 steel. A cutting from the tip of the core barrel and, for comparison, a cutting taken 2 feet higher up were submitted to the Bureau of Stand- ards with the request that the temperature to which the tip was sub- jected be determined as closely as possible. The report was accompanied by two micrographs showing the difference in structure: These are re- produced in figure 3. The conclusion reached is that “the structure at the tip indicates that the metal was heated above the upper critical range ($00 degrees centigrade) and then cooled fairly rapidly (more rapidly L Sa FicurE 3.—WMicrographs of Steel from Core Barrel a, unheated steel 2 feet from tip; b, heated steel tip. The change of structure is due to the heating of the steel at tip to a temperature “as high as 1,050 degrees centi- grade,” followed by rapid cooling. than in air). The tip of the pipe was not heated long enough to produce pronounced grain growth, which occurs in this type of steel after pro- longed heating above 950 degrees centigrade. It was estimated, however, that the temperature reached was as high as 1,050 degrees centigrade.” * This independent evidence is in agreement with the conclusion reached on an earlier page, that the temperature was in the neighborhood of 1,100 degrees centigrade. PRODUCTION OF HEAT BY FRICTION It is rather difficult to picture the conditions under which a steel, heated to a temperature at which it can be forged, though not easily, could nevertheless act as an abrasive in cutting rock. It is to be noted, however, that on account of the good conductivity of the pipe only the extreme tip was so heated, so that a tearing off of the softened end would expose cooler and stronger steel for further cutting. As a matter of fact, it is very doubtful whether any further cutting was accomplished after this condition was reached. Probably the principal action at this *Report from Mr. 8S. Epstein: U. S, Bureau of Standards. ) 440 BOWEN AND AUROUSSEAU—-FUSION OF SEDIMENTARY ROCKS stage was a twisting of the rock contents of the core barrel on the rock immediately below it and of adjacent layers of the core material on each other. To such action rather than to the turning of steel on rock is to be assigned the larger measure of production of heat required for the fusion that resulted. We may get an approximate figure for the heat produced by friction, since the pressure resting on the core and the rate of revolution are known with fair accuracy. The pressure was about 20 tons, the rate of revolution 25 per minute, the radius of gyration 1.5 inches, and the coefficient of friction of rock matter on rock may be as great as 1 or even greater.” Taking a coefficient of friction of 1, it is found that about 3.14 10° foot-pounds of work would be expended in friction at or near the end of the core barrel in the 40 minutes during which very slow progress was made. This is equal to about 10% calories. Assuming a specific heat of 0.22 calorie for the material heated and a latent heat of 100 calories per gram, the amount of heat developed is sufficient to raise to 1,100 degrees and partially fuse (50 per cent conversion to liquid) about 37 kilos of rock. Only about 6 kilos of rock actually were so affected. Of course, all the heat generated would not be avail- able for this effect. Some of it would be used in heating the surrounding rock, but this amount would probably not be great on account of the poor conductivity of rock, especially when porous. A large amount would be conducted away by the massive pipe line, but even this good conductor, with the tip heated to 1,100 degrees centigrade and a temperature of 100 degrees centigrade only 20 centimeters higher up the pipe, would carry away but 200 calories per second. The friction is capable of pro- ducing about 4,000 calories per second. It is not unreasonable to expect, then, that, of the heat produced, a sufficient quantity was available to melt 6 kilos of rock. CorE FROM “MrEyrER 6” WELL OF THE UNION Orn Company This well is located at Santa Fe Springs, Los Angeles County, Cali- fornia. Professor Willis sent us part of the fused end of another core from the above-named locality, obtained at a depth of about 3,000 feet. No sample of the unfused sediment is available for comparison in this case; but, though much glass is formed, it is plain that the original was an arkose-like material of considerably coarser grain than the Montezuma sediment. The unfused grains are again quartz and plagioclase (about ° Peele’s Mining Engineers’ Handbook, p. 1961. CHARACTER OF CORE FROM “MEYER 6” WELL A4] Ab,An,) and there is a great abundance of small fragments of iron from the pipe. The chemical composition of this core is shown in Table IJ. The amount of metallic iron was so high as to render useless Pratt’s method for the determination of FeO. Ht was not found practicable to remove this iron with the electromagnet. ' The greater part of the error of analysis here undoubtedly devolves on the determination of metallic iron. Check determinations of the total iron were made and were in satisfac- tory agreement. From these the amount of FeO in the fusion was calcu- lated by subtracting the metallic iron, expressed as FeO, from the total iron as FeO. Considerations similar to those given in connection with the Montezuma core lead us to believe that there is no ferric iron present. TABLE IJ.—Fused Core, “Meyer 6” Well, Santa Fe Springs, Los Angeles - County, California 1 2 3 4 OMe 8 roa oye Shc des eusiare cane & 65 .45 65.11 68.95 68.16 Pap ME eer ar 2c s wie oie wie ete e's 14.3 14.28 15.12 14.95 Lb, seo ee ree none none none 0.95 ROE ore en cia 5 Se Sik wi Se 6 berms 4.67 4.65 4.92 2.92 NE Re Bo iS lia ale, wisi oie cw Gee 5.60 5.57 sae anaes LoS > 4.5 ene 0.86 0.85 0.90 1.58 ELD nn i 5 eee 2.48 2.47 2.62 Pincers 22g. a eS eee 32 3.50 aye tad 4.13 NU uc co sas aie oop Sta.e's 2.90 2.88 3.06 2.89 TESS op Sears Se ae ene ae O15 1.36 2 Eig neniasiacanan 0.05 ; ps aes ae vols cide Sc) ya ee ee eee none none none eticle pe IE SS 2 oer 55's Ul eye sid boo 8 eu ee 0.30 0.30 Osh 0.90 MMR ans no ch ch aeFalla x a'e «3 haat Op Zale - ¢ 0.21 O22 none it nae oo pe SORE ea aiiaeen racer pnd. pend: pond: ete 2S) ne See ae aoa eer as Pisban s Saad 0.05 NOMME NEN orotate a: ee arene ae Swe SC Dane d. Dp: n.d. p. n.d. none ODUCT, Ney pa aR PS ae ee a 100.52 100.00 100.00 100.49 1. Composition of sample. M. Aurousseau, analyst. 2. The same, calculated to 100. 3. Composition of fused sedimentary material calculated from 1 by deduct- ing metallic iron and reducing to 100. 4, Aplite, Zeia River, Amur District, Siberia. W. Giers, analyst. E. Ahnert, Hapl G. Ree, Aurif. Sib:., X, Taf. VII, 1910. The chemical analysis, recalculated by deducting metallic iron to de- termine the actual composition of the rock matter (Table II, number 3), confirms the indications of the microscope that the rock was of the nature a 442 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS of arkose. It is rather closely paralleled in composition by an aplite from Siberia (Table II, number 4), but its norm (Table III, number 3) shows the same departure from typical igneous composition as do most sediments, though in this case it 1s of very moderate degree. SYSTEMATIC POSITION OF THE FUSED SAMPLES The analyses of the fused cores show that both differ in composition in the same way from ordinary characteristic sedimentary material (see Table III). The principal feldspar identifiable under the microscope in the original sediment of the Montezuma core is a basic plagioclase, but the analysis shows that the alkaline feldspars are much more abun- dant than the calcic. It can only be concluded that the finer-grained, so-called claylike, matter of the arkose and of the shaly layers in it is in reality but moderately kaolinized alkaline feldspars. Unquestionably the sediment is the result of processes in which rock comminution domi- nated over rock decay. The same would, no doubt, be true of the original sediment of the “Meyer 6” well as shown by the analysis of the core. TABLE III.—WNormative Compositions and Systematic Positions of Cores ik 2 = Oath ero soc tas ie teens ast 22.64 25.26 25.20 COMUn GN 25s cae sales eeska shore ey. On 4.49 1.48 GrenOclase Gars.ke wie. ww era nee oes dS) 12.79 18.35 Davi] Ov) AOR yumeE tPA iM in ent Acar cB 28.82 29.34 31.44 APOTEDTKE ..5/oaupeieeanail se nc eraeee 15.29 15.29 11.68 PV Persineme:. say se ete a ate aPeke 14.60 11.06 10.75 Timenite™ <. Posse ane eee L222 teen 0.61 AATCC: 2s sete nhantetne Akio tetoe an 0.51 0.40 0.35 PERG; 2,5) caaeate ane de ere teh O20) ow A Ss Se edee 8) eee WiSGeR 2 26h 2s sicisicte seme eae Moscone U2 GT eit ak, oer ae 0.19 SSUITINED Zac myeteiee ¢ GaPeinua lakes are 4 100.00 100.00 100.00 “I 4."S\.4. (1) EL. 43:42" 1D eae ee Tonalose. Tonalose. Lassenose. 1. Fused core, Montezuma well, near Suisun, Solano County, California (number 3. Table I). 2. Hypothetical result of fusion of Montezuma sediment (number 3, Table VA Ne a 3. Fused core, “Meyer 6” well, Santa Fe Springs, Los Angeles County, Cali fornia, deducting metallic iron (number 3, Table IT). As a result of this fact, these cores depart but little in composition from an igneous rock. The Meyer core has already been compared with an aplitic rock. In Table IV the fused product from the Montezuma SYSTEMATIC POSITION OF FUSED SAMPLES 443 well is compared with a malchite from Zwingenberg, Baden. It is possi- ble also to match fairly closely the hypothetical fused product (calculated from the analysis of the original sediment assuming a loss of all volatile constituents and no addition of iron) with a quartz diorite from Electric Peak, Yellowstone National Park. TaBLE 1V.—Comparison of fused Core with igneows Rocks 1 2 3 4 ae 6 7 SD Ree eee 64.40 63.18 65.94 65.11 58.63 64.18 61.02 PANOls. se cisisisie a's Suse Lilo. Pio elon wonder aS. OO GL OL o! 1.85 ROO Nol ca oye si wa iy. sh none 0.24 none 1.06 1.93 4.44 + 3.92 } SO) Gai sae aan ara mera 6.53 GOK 4.24 3.19 6.46 3.05 3.48 LOO) Sar aaa Pare tty 0.92 1.65 PASO 2.62 ong 3.60 9 OL Ae Reece Bos 4.17 3.26 3.97 0.56 3.41 Tie SOS 2A ee ee ee 3.42 4.44 3.50 4.00 2.58 £39 3.96 MRO Nein os Sichs /sile -s) avocets Ze PASE BN Dass 2.51) 2.01 3.56 oe 20 ne One go ienegan 4.45 ) Oe le eile let a. wiles Sis 0.02 § 11.38 ta acess ein sence » none aes Lees aero none NO) eer 0.62 es ais 0.62 O27 1.01 PP ha ves oxen 'd a 6 0.28 0.23 0.22 0.02 0.08 SOM eis Cla as oes re 0.19 eet as trace Me ecche vee ae ee Cet Dabate Sana none ‘ Shes chou’ Re aeero eee eee are 0.06 seit aera ath none CBO ycie eis shove ele trace RetNs Sch. woe wave CO BG en 0.07 eid 0.06 none 0.38 ENO ONO sie ss stow ee gas ene Meee 0.03 ESO) oo 2 NOS eee eee 0.08 raneke 0.07 Setiese 0.06 SID) ka eee a eran bp a PAE eae Cen trace ILO) Se aaa ee LAY 3 Se Reutrgs 0.04 STUDI ag ae ee nee 100.02 100.20 100.00 100.33 100.77 100.00 100.00 NESS ines Oe eas ela aia -ch . 02 S010, a eee me 100.00 100.20 100.00 100.33 100.77 100.00 100.00 1. Fused core, Montezuma well (number 3, Table I). 2. Malchite, Zwingenberg, Melibocus Mountains, Baden. MHeurich, analyst. A. Osann, Mitt. Bad. Geol. Land-Anst II, 1893, page 385. 3. Result of fusion of Tejon sediment of Montezuma well, assuming loss of volatile matter and no addition of iron. 4. Quartz diorite, Electric Peak, Yellowstone National Park. J. F. Whit- field, analyst. J. P. Iddings, United States Geological Survey, Annual Report Mi AetSOl, paze 627. 5. Buchite (fused phyllite) Sailean Sligenach, Ardmucknish, Argyllshire, Scotland. W. Pollard, analyst. Memoirs Geological Survey Scotland, number 45, 1908, page 182 Average shale as calculated by Hobbs. . Average igneous rock as recalculated by Hobbs for prmaipat constituents ees om the results of Clarke and Washington. 444 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS These rocks belong to the subrang tonalose, but inspection of this sub- rang in Washington’s tables shows that they differ in composition from typical igneous rocks in the same way as the average shale differs from the average igneous rock. In the closest general matches obtainable, lime is distinctly higher and the ratio of soda to potash greater in the igneous rocks. Moreover, were all the analyses in columns 1—4+ of Table IV reduced to 100 after excluding water, this divergence would be in- creased. It was also evident, in our endeavor to match an igneous rock with the Montezuma sediment, that the closer parallels were often igneous rocks of unusual compositions, such as schlers in granites. In matching the fused sediment from the Meyer well (see Table IL) it was found that most of the lassenoses resembling it showed higher figures for MgO + CaO and a greater ratio for soda over potash. GENERAL CONSIDERATIONS REGARDING THE FUSIBILITY OF CORES There is a very strong suggestion in the information gained from these and other studied cores that arkose is particularly susceptible to the fusing action here described. This is as it should be, for, contrary to the common misconception, a mixture rich in alkaline feldspars and quartz should constitute the most fusible material to be made up from ordinary rock-forming minerals. Frequently one will find in the liter- ature the statement that femic material fuses more readily than salic; but this is due to the failure to distinguish between fusibility and fluidity. It is true that femic material forms a more fluid melt than salic material, but it is likewise true that a salic melt can be obtained at lower temper- atures than can a femic melt. We refer here to anhydrous conditions, not to the conditions obtaining in magmas where this contrast is further emphasized by the fact that the salic magmas ordinarily contain more volatile matter than do the femic. The greater fusibility of salic ma- terial is well brought out in the studies of Sosman and Merwin on inclu- sions of arkose in the Palisade diabase, which were found to fuse in the laboratory at a temperature 100 degrees centigrade lower than the fusion temperature of the diabase.® REFUSION OF SEDIMENTS AS A Factor In Macama GENESIS The arkosic nature of the sediment that was fused to form these cores and the consequent close chemical approach of the cores to an igneous rock are matters that require emphasis for another reason. Some geol- 6 Tour. Wash. Acad. Sci., vol. 3, 1913, p. 394, REFUSION OF SEDIMENTS AS FACTOR IN MAGMA GENESIS 449 ogists believe that igneous rocks are formed by the refusion of sediments, and the similarity of these cores to igneous rock might be regarded as furthering this belief. The original sediments were, however, in this case exceptional in character, and such material can not be regarded as generally available in large quantity for the desired action. Ordinary shales are, however, to be regarded as available in quantity, and Hobbs, one of the supporters of the refusion hypothesis, would make them the starting point for the formation of lavas.’ By tabulating side by side the chemical composition of average shale and of average igneous rocks (repeated here as columns 6 and 7 of Table IV), Hobbs is able to show a certain broad similarity. At the same time there are distinct differences that are thoroughly characteristic and carry with them definite consequences. The average shale shows a marked dominance of potash over soda and an excess of alumina over that re- quired to make alumino-silicates with the alkalies and lime. Now, as a consequence of these characters, the refusion and recrystallization of such average shale would lead to the formation of such minerals as silli- manite and cordierite, which are not formed from uncontaminated igneous magmas. If igneous rocks are ordinarily the result of fusion of shale, the common absence of such minerals in them is rather surprising. Hobbs would supply the deficiency of alkaline and alkaline-earth bases in his fused shale by supposing that beds of hmestone and of salt are absorbed by the melt as it rises toward the surface. Such absorption, though remarkably selective, can not be denied all credence, but one is still puzzled as to how this deficiency is made up in those laccoliths which he imagines to be the result of the fusion of shale in situ. The chemical difficulties encountered by this hypothesis are, however, even less formidable than the thermal difficulties. Hobbs states that “most rocks would fuse at a depth of fifteen miles on the basis of dry conditions only.” The temperature at this depth would be 740 degrees centigrade, accepting the geothermic gradient given by Hobbs, and even a salt bed would not melt at that temperature. For the dry fusion of the arkose of the Montezuma core a temperature corresponding to a depth of 23 miles would be required, and this arkose is certainly more fusible than typical shale. It is not, however, to dry fusion that Hobbs appeals for his principal results. Citing the known great effect of water in lowerng the melting point of silicates, he imagines that the temper- ature at a depth of only 6 miles is adequate to melt shale. Again using * Earth evolution and its facial expression, New York, 1921, pp. 28-61; also Gerland’s Beitrage zur Geophysik XII, 2, 1913, pp. 329-361. 446 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS the geothermic gradient given by Hobbs, we find this temperature to be about 315 degrees centigrade, which is scarcely acceptable as a temper- ature at which fusion of shale, even retaining its water, is to be credited. Particularly is this true when the nature of the process postulated is considered. The shale is supposed to fuse as a result of relief of pressure. Now, it is true that most silicates and silicate mixtures expand on melt- ing, and that for any such mixture there is probably a combination of temperature and pressure conditions such that an isothermal® relief of pressure would cause melting, though whether such a combination of temperature and pressure conditions obtains anywhere in the earth’s crust is a question. But, even assuming that such a combination does obtain for anhydrous material, as soon as a volatile component enters into the system the whole aspect of affairs is changed. Thereafter the principal effect of lowering of pressure will be to decrease the amount of volatile component which the rock matter is capable of containing, with a consequent raising of the melting temperature. Plainly the great lowering of melting temperature through the presence (under pressure) of volatile matter, and the lowering of melting temperature by lowering of pressure in anhydrous silicates, can not be considered as working together in any hypothesis of magma genesis. The only promising method of fusing shale would appear to be to have it exposed, retaining its water, to a temperature of some 850 degrees centigrade or more. If this temperature is to be the result of the normal thermal gradient, the requisite depth would presumably be about 17 miles. Under these conditions most shale would probably be fused, but, be it noted, relief of pressure would tend to cause it to crystallize. Whether shales ever become buried to such depths is questionable. Under the influence of heat brought from the depths by basic magmas shales have sometimes been raised to some such temperature as that just mentioned and have been fused. An analysis of such fused shale (phyl- lite) is given in Table IV, number 5. As will be noted, the conditions were such as to permit retention of water, which is probably essential to the fusion of shale by any magma. The process is probably one of no great quantitative importance, though possibly shale may, on occasion, be thus refused in sufficient amount to give rise by reintrusion to distinct bodies of small size. To such action may, perhaps, be attributed the abnormal voleanic necks in Lake Janisjarvi, Finland, described by Eskola.® S The word isothermal should be carefully noted. It is doubtful whether any such action could be realized in the earth’s crust. ° Bull. Com. Géol. Finlande, no. 55, 1921 REFUSION OF SEDIMENTS AS FACTOR IN MAGMA GENESIS 447 SUMMARY When a core sample of the beds penetrated is taken during the drilling of an oil well, it is found, under some conditions, that part of the core - consists of a slaglike mass bearing some resemblance to a natural lava. This slag has been pronounced by some geologists to be the result of fusion of rock in the drill-hole as a result of the heat of friction, though some operators have been unwilling to accept this conclusion. The ex- amination of two drill cores sent us by Prof. Bailey Willis, in one of which the beds immediately above the slag were well preserved, has con- firmed the opinion that the slag is the result of fusion of the sedimentary rock in place. Chemical analyses of sediment and slag show that they are practically identical in composition, except that the fused part or slag has lost nearly all its ,water, all its CO,, and about one-half its sul- phur, and has received a considerable contribution of iron from the drill pipe. Thermal tests in the laboratory show that a temperature nearly, if not quite, as high as 1,150 degrees centigrade is necessary to produce the results actually obtained in drilling. A metallographic study of the steel shows that the temperature attained was 1,050 degrees centigrade or higher. | - The chemical composition and the microscopic characters of the ma- terial fused show that it was of the nature of an arkose, a variety of sedimentary rock which appears to be particularly susceptible to such fusion. Since the rock was an arkose, the slag shows only a moderate departure in composition from an igneous rock, but the difference is none the less real and is in the same direction as that exhibited by typical shales. On account of the arkosic nature of the sediment the general chemical similarity of the slag and igneous material can not be regarded as affording any support to the theory that igneous rocks are formed by the fusion of shale, nor do the thermal results favor the view that remelt- ing of shale could occur at moderate depths in the earth’s crust (say 6 to 10 miles) unless the normal temperatures prevailing at such depths are notably augmented by intrusion of igneous matter from greater depths. DISCUSSION Dr. Stoney Powers: This paper is interesting from the viewpoint of petroleum geology. These cores are taken with the rotary system of drilling, and an ordinary piece of pipe is attached to a sawtooth edge which is all rotated with whatever mud happens to be in the hole. The 448 BOWEN AND AUROUSSEAU—FUSION OF SEDIMENTARY ROCKS weight of drill, with speed of rotation, fuses the cores in case the rotation is rapid, and the end of the core (barrel) is very commonly fused, some- times partially fused. The material which is fused has become so com- mon that we now call it cortte. It was first found on the coast in drilling on salt domes. It is very common to use rotary drilling in fusing. An article on core drilling appears in the Monthly Review of Oil Fields ot California, published by the State of California. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 449-458 SEPTEMBER 30, 1923 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY CARNIVOROUS SAURISCHIA IN EUROPE SINCE THE TRIASSIC + BY F. VON HUENE (Presented before the Paleontological Society December 30, 1922 CONTENTS Page Mesa semraremanetet nial Geer) hula ass erate inila. aiiay Gia alias wel ane sh: eh Pe MS SMA Aa sD ey OR ae 449 Specimens from Lower Lias and Lower Oolite of England................ 450 Sean ROR NAT CUTE AITTG AT TeV RCE oh cnatia gta oie) oS a iapisi'n pe calles =, coe) Se wlsiallol ei ete.'e Shay aia! se ehie enarlde ia al 6 453 ae Ore nile, NCO AOSATITIOE 2 oa, 6 6 ssw awe cs oe ap wales Ms bce wr esa nie ences 457 INTRODUCTION In the Jurassic and Cretaceous of England, and France particularly, but also in several other countries, many skeletons, and principally frag- ments of such, have been found, only a few of which have hitherto been described and named. Many of these remains have been referred to in the literature as Megalosaurus bucklandi. At present without special studies it is scarcely possible to ascertain what is meant by this term. Therefore I think it may be desirable to publish my studies on all of these forms, made in recent years in many museums of England, France and other parts of Europe, and in America, together with what is known from the literature. Two years ago in another place (“Williston Memorial Volume,” not yet published) I assembled and enumerated all these specimens. I found ninety-seven in Kurope and fifteen in other parts of the world except North America, but not all of them were useful for accurate determina- tion and comparison. The type specimens I have redescribed from my own observation and I have figured some and made restorations of a few of them. Several new species and even new genera have also been described. 1 Manuscript received by the Secretary of the Society March 15, 1923. XXX—BULL. GEOL. Soc. AM., Vou. 34. 1922 (449) 450 F. VON HUENE—CARNIVOROUS SAURISCHIA IN EUROPE SPECIMENS FROM Lower Lias AND LOWER OOLITE OF ENGLAND In the English Lower Lias and in the Lower Oolite there are forms which, while closely related to the genus Wegalosaurus, yet do not really belong to it, since they lhe somewhere between Teratosaurus and Megalo- saurus. For the present I shall not assign a name to this genus. The tibia of these specimens is characterized by a rudimentary crista lateralis at the lateral side of the proximal end and below its head. In Terato- saurus this crest is still missing and in Megalosaurus it is strongly de- veloped. The species from the Parker collection (Oxford) from Nether- comb (Humphriest horizon of the Lower Oolite) I have named “Megalo- saurus” nethercombensts n. sp. Its pubis is rodlike in the distal (anterior) portion. The teeth are similar to those of the true Megalo- saurus bucklandi, but, among other differences, are somewhat thicker than in that species. The true Megalosaurus bucklandi occurs only in the Stonesfield slate just below the Great Oolitic. So much of the skull is preserved that a restoration, within certain limits of error, is possible. This skull ex- hibits some resemblance to Antrodemus. The cervical vertebre are high, relatively short, and opisthoccelous. Neither the cervical nor the dorsal vertebree show the pleurocentral excavations so sharply circumscribed or so deep as in Streptospondylus or in Antrodemus. The number of pre- sacral vertebre is not known, but there is no valid reason why it should differ from that in Streptospondylus cuviert, which has nine cervical and fourteen dorsal vertebree. The dorsal vertebre show only pleurocentral depressions, but not cavities. Below the diapophysis are strong support- ing buttresses, with deep niches between them. The neural process is broad and thick, but not very high. The sacrum, as is well known, con- sists of five vertebre. The anterior caudal vertebre are as long as the dorsals. The hemapophyses are like those in Antrodemus. The scapula is long, slender, and straight, as in Antrodemus, and its processus del- toideus is very high. The humerus, which is robust, is about half the length of the femur and a little more than half the length of the scapula. The ulna and radius are scarcely more than half as long as the humerus and are extraordinarily stout. Unfortunately the manus is not known. In the pelvis the pubis is a narrow and distally rodlike bone, but is not completely known. The proximal expansion containing the obturator foramen disappears within a short distance of the proximal end. The ischium exhibits an angle in the middle of the shaft. The ilium is rather large and has a broad anterior spine. The trochanter major on the femur is a broad fanlike crest for the iho femoral muscle, corresponding there- SPECIMENS FROM LOWER LIAS AND LOWER OOLITE OF ENGLAND 401 fore with the large spina iliaca anterior. The distal condyles of the femur are separated by a broad groove even on the dorsal side. The tibia has a typical lateral crest near its proximal extremity. In the metatarsus a fifth metatarsal is not known and probably did not exist, so the pes stands between Teratosaurus and Antrodemus. Deslongchamp’s Potkilopleuron bucklandt, from the Middle Dogger of Normandy, is only a rather large Megalosaurus, probably of the same group as M. bucklandi at Stonesfield. Since the specific name of these certainly different species would now be the same, the latter might better be called Megalosaurus potkilopleuron. The bone which I had mistaken some time ago for a pubis is rather a scapula. As a pubis its dimensions should be double. Therefore my former conclusions made from the form of the “pubis” are invalid. Of considerable interest is the fore limb with the manus. The humerus is very stout. Its length I should estimate, from a special study, as about half of the length of the tibia. The fore- arm is extraordinarily short and heavy. The radius shows a prominent muscular process in the middle of its length. The manus has five fingers, as in the Triassic Plateosauride, and differs from the later Carnosauria. The manus is relatively large. A very well known form from the Oxford clay is Megalosaurus (Streptospondylus) cuviert, found in England and in Normandy. The best skeleton existing is that from Wolvercot in the Parker collection (Oxford), which I have studied in detail from Nopsca’s short descrip- tions. The skull, much of which is rather complete, differs in some minor points from that of Megalosaurus buckland1, of which much less is known. The importance of this specimen lies in the completeness of the vertebral series (nine cervicals, fourteen dorsals, the first three sacrals, and twenty-nine caudals). The cervical and anterior dorsal ver- tebree are deeply opisthoccelous, but this condition decreases posteriorly. Especially well developed are the neatly circumscribed pleurocelous cavities, also decreasing toward the tail, but in the anterior dorsals they are still quite distinct, although soon becoming flattened. The cervicals are relatively short and high and the dorsals are relatively low. The sacral vertebre have saddle-shaped articular faces. The shoulder girdle is similar to that of Megalosaurus bucklandi. The humerus is less heavily built than in the latter form and has not half the length of the femur, or even of the tibia. The manus is relatively slender, but is in- completely known. In the pelvis the ilium is much like that of Megalo- saurus bucklandi and the same is true of the pubis, which has the medial lamella more developed in the proximal portion. The distal extremity Fr. VON HUENE—CARNIVOROUS SAURISCHIA IN EUROPE ‘YS (BANIOU YVAIX{S-3UQ “Pa1j0p 918 sy1Vd Bujssym ayy, ‘aAnepuoy, wosy vaupoods #L1v 94d woss #JUjOd May B Ul pavassOZy ‘“ss[YSJOHIOG “YOOAPAIOM ‘BID psojxQ ‘“UaUIIDeds 8 AOYIV] “AJL WOsS SPVOL BUM UOLBAOJHOA DULL wayne (amphpuodsodayg) snsmogooba yy JO WOYDLO{IIY NOAN—“"[ ABAOLA EP y " Fa TM Ne Se” Co LF ie Ee Tl Badd - IASI fifo ee LE ‘ii mo) 2 BD eS Kt 1 STII fer. (igi Ae ‘SPECIMENS FROM LOWER LIAS AND LOWER OOLITE OF ENGLAND 453 does not exhibit any hooklike thickening. The ischium differs from that of Megalosaurus bucklandi in having a rather straight shaft. The femur is less curved and the distal end is broader than in Megalosaurus buck- landi. The tibia has a well developed crista lateralis near its proximal extremity. The fibula is very slender. The form of the processus ascendens astragali resembles that of Megalosaurus poikilopleuron. The metatarsals and phalanges are much more slender than those of M. buck- landi. Although it is possible that a fifth toe once existed, there is now no indication of it. It is doubtful whether it is necessary to distinguish this species from the true Megalosaurus by a separate name (Strepto- spondylus). The reasons for doing so would be the deeper pleuroccelous cavities and the slenderness and certain minor characters of the skull. Another Megalosaurus from the Oxford clay of Weymouth (Dorset- shire) in the Parker collection I call M. parkeri. This specimen is char- acterized by high dorsal spies, an ilium differing in form from that of M. bucklandi, a very narrow pubis with large obturator foramen and a thick, hooked distal end, an ischium with lateral longitudinal ridge near _ the articular face, and a tibia whose enemial crest projects greatly for- ward. This species differs more from the true Megalosaurus than does M. curieri, only in another direction. SPECIMEN FROM FRANCE ~ Of “Megalosaurus’ insignis (De Longchamps), from the Kimmeridge of France, not much is known except large Megalosaurus-like teeth and stout phalanges. The species described as M. dunkeri by Lydekker (Dames), from the English (and German) Lower Wealden, is distinguished from Megalo- saurus by its enormously high neural spines in the dorsal region. I therefore propose to establish a new genus, Altispinaz, for it. M. owen (Lydekker), from the British Upper Wealden, belongs to the same genus. This genus apparently develops from Megalosaurus parkeri. It is shown, therefore, that the true genus Megalosaurus occurs only in the Middle and Upper Dogger and lowest Malm. The earlier and later forms, although differing somewhat, are allied with it. Quite a different form is that described by Sauvage as Megalosaurus superbus, which I call Erectopus (n. gen.) superbus, from the Middle Cretaceous of northern France. The relationships of this genus are not yet evident. It is characterized by the peculiar form of the femur. The proximal end above the trochanter major is greatly curved medially and the fibular condyle at the distal end is considerably more developed than CARNIVOROUS SAURISCHIA IN EUROPE HUENE F. VON 454 “O“IS [RANJLU UY}J[OMI-0UO ‘po}jop oaB suo;jaod Sulsstm oy, “RMRARG ‘UsJoyULO, JO puB]}AOT Of} WOAJ ST uautoeds SIL SAMOUO] SNYPDUBOSUAMOY) JO WO1L.DAOZSA NAN-—~"G ANNO a Ao EE SPECIMEN FROM FRANCE 455 is the tibial condyle. This condition is the reverse of that found in the Megalosauride. The distal portion of the shaft is less curved than is the proximal half. From the curvature it is concluded that the whole hind limb was much straighter than in the Megalosauride. This is _ shown also by the position of the articular face of the caput femoris. The dorsal centra are relatively high. The tibia has a greatly projecting cnemial crest and the crista lateralis is unusually close to the proximal end of the bone. Metatarsal II is nearly half the length of the femur, which is exceptionally long. A portion of the manus is preserved, show- ing very slender phalanges. The first phalange of the thumb is short and the claws are small. An element found isolated is much like meta- carpal V of the Plateosauride and of Megalosaurus poikilopleuron; it would be surprising, however, if a fifth digit were still present. All of these remains (and more) have been found so closely associated that they probably belong to a single individual. All of the former genera belong to the Carnosauria. Of the Cceluro- sauria there are but few forms. Of this group Sarcosaurus wood, from the English Lower Lias, was recently described by Andrews. Ilium, pubis, and vertebre exhibit the characteristic form, which is also seen in Procompsognathus, Ornitholestes, aud Ornithomimus. Compsognathus longipes (Wagner), from the Portland of Solenhofen, is well known. I have made a new restoration of the skull and of the whole skeleton. There are ten cervical vertebree (beginning with the atlas), thirteen dorsals, and five sacrals. The humerus, although not distinctly recognizable at its proximal extremity, shows the processus lateralis extending two-thirds of the whole length of the bone. The reconstruction of the manus exhibits a form reminiscent of Ornitholestes and also of Ornithomimus in some respects. The skull, as in all Coeluro- sauria, is much more primitive than in the Megalosauridx, as is seen from the base of the skull, the palate, the temporal openings, and the large orbits. . The vertebra from the English Wealden Calamospondylus foxi, by Lydekker, is a ccelurid, and the sacral remains from the same horizon, which Seeley described as Thecospondylus daviesi, seem to me rather different from the other species of that (so-called) genus. I therefore propose the new generic name Thecocelurus. More satisfactory are the remains of Aristosuchus pusillus (Seeley), also from the Wealden of the Isle of Wight. The vertebre, pubis, and claw show this specimen to be a true ccelurosaurian. The claw described by Dollo as Megalosaurus lonzeensis, from the 456 F. VON HUENE—CARNIVOROUS SAURISCHIA IN EUROPE Senonian of Namur, and the femur described by Seeley as Megalosaurus breda, from the Maestricht beds, I consider ornithomimids. GENETIC SCHEME Ornithomimus altus etc. ie rex A\lbertosaurus Gorgosaurus an Ornithomim. gen.Maestricht Drome@osaurus Genyodectes Ornithomim.gen.Belgium ap) > (CO WRO- Shi ra) (CARNOSAURIA) : rec < = Altis ee, 35 Coelosaurus(?) Dryptosaurus ae oe : affinis equluneule Altispinax | danke ! 2 Thecocaelurus ? Elaphrosaurus Ornitholestes Coelurus Ceratosaurus Antrodemus “Meg-sp. | valens Meg-insignis| Compsognd hus Meg.No.23Davies Proceratosaurus Meg. bucklandi Meq. poikilopleuron ! “Meg nethercombensis i 2 Tibia,Wilmcote Hallopus Coelophysis ! Procompsognathus | Halticosaurus Teratosaurus * Podokesaurus | ve aS | y, . H kg ~ 2 2 G : : ; Cladyodon I+ Tie ee Zanclodon wo oO Tanystropheus FIGURE 3.—Genetic Scheme Among the extraeuropean skeletons Janenesch’s Hlaphrosaurus bam- bergi, from the Tendaguru Kimmeridgian, also belongs to the Ceeluro- sauria. HABITS OF THE MEGALOSAURIDZ ADT The American Morrison genus Ceratosaurus has also been recognized (the evidence is given elsewhere) as a coelurosaurian, but resembling in some respects the Megalosauride. HABITS OF THE MEGALOSAURIDZ I have discussed at length the phylogenetic and biological features in the paper mentioned above. For the former I give only a diagram and for the latter the following results: The small fore limb of the Megalosauride, especially of the latest forms, and of the Deinodontide, with the large manus and enormous claws, which was no longer able to reach the mouth, could not have func- tioned in holding the prey or in tearing it to pieces. The hind limb, together with the mouth, must have been used for this purpose. The fore limb was doubtless useful in the killing of victims, in rivalry fights, in sexual activity, and in hatching and brooding the eggs and young. The relatively large fore limb of most of the Ccelurosauria, with its manus highly specialized on a primitive base, certainly served as a well developed grasping organ. It is supposed that the habits of Ornitho- mimus (Struthiomimus), the toothless terminal member of the Ceeluro- sauria, were adapted to digging out small vertebrates and other animals, or rather to scraping out and stealing the eggs of large reptiles which were hidden in the ground. The opisthoccelous condition of the anterior presacral vertebre of the Megalosauride and of the Deinodontide is explained as an adaptation to the habit of tearing the prey to pieces. The victim was probably held with the hind foot of the captor, the flesh was seized with its teeth and pulled off, upward and foreward, and in so doing the vertebral column had to double up and vigorously jerk upward. In the ccelurosaurian genus Ceratosaurus a “quasi-opisthoccelous” con- dition is developed in the anterior presacral column, because it had adopted rapacious habits resembling those of the Megalosauride. , Pah f VGA tt Rep ee ‘ay ry. Pi, Uae a “VG CaN pre) BUS ia Pin Rn tae aged SE hey ia haar eae Pia Eat Hie ik a a Magee cae tie ann wel oe . day ote wns f eG amet Psi Ame ell aca io Pe ay "VF UA wa ; ~, Get A Be a? a TOR te eo ma at 7 saith ard < é i eto a * ‘ Cee aire es Liew Be : ie Eve er » fe 7. ao tees plc hie ; > a . tH m ¥ wb, > | i a ¥ Pty ar Neer, a Ce ’ - ad A J f ” | ’ . ry , - pi “ ‘ ‘ me eS ae ‘en ty As, Me A @ : BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 459-462 SEPTEMBER 30, 1923 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY CONTRIBUTION TO THE VOMER-PARASPHENOID QUESTION * BY F, VON HUENE (Presented before the Paleontological Society December 30, 1922) CONTENTS Page UN GMEGE RD a DS ee ee 8 ise Bho Piaybin ood chp es bedias awl we ato aie oo aselb eee de 459 ame Oto VETILEAL GSIGC Of SIGUE 25 F 2 wee win Scie oc ci 5 wines + wat noe ceeeee 459 Le Mase! Ae WHDOTIANE LAChS oes 7 ols 22 asa ee ss ols tae bet Oe a ce eee 460 INTRODUCTION Recently I have examined a very perfect skull of Dicynodon sollasi (Broom), of the Upper Permian Hndothiodon beds from Biesjespoort, Cape Colony, South Africa,? which I had received as a kind donation from Dr. R. Broom. One of the results which seems to me of importance concerns the vomer question. CHARACTER OF VENTRAL SIDE OF SKULL The ventral side of this skull indicates the following characters: The anterior portion of the basisphenoid possesses a long rostrum directed obliquely upward and in a higher plane than any part of the palate. The upper and posterior portion of it forms a thin and moder- ately high median blade, which I take for the presphenoid. The thicker and lower part of it, which extends to the anterior side of the orbits, I regard as the parasphenoid. Below the branching of the rostrum basisphenoidei the pterygoid touches the basis cranii in the usual manner for a short distance un- divided. It then separates anteriorly and thus forms a long and narrow interpterygoidal space. ‘The latter is surrounded posteriorly by the 1 Manuscript received by the Secretary of the Society March 15, 1923. 2Pal. Zeitschr., v, 1, 1922, pp. 58-71. (459) 460 ¥F. VON HUENE—THE VOMER-PARASPHENOID QUESTION pterygoids and in the middle and anterior portion by the bones which I regard as the vomers. The pterygoid and the vomer are in contact. Be- tween the greater portion of the vomer and the anterior extremity of the pterygoid the palatines are interlocked. The internal nares are separated by a septum partly formed by the vomers (posteriorly and above) and partly by the fused premaxille, covering that part of the vomer from below. The lateral walls of the internal nares are formed by the palatines. Between the pterygoid, palatine, maxilla, and jugal the transversum is situated. PRESENTATION OF THE IMPORTANT Facts These are the important facts. The bones which I regard as the vomers are separated by the ptery- goids from the basisphenoid by the length of the entire basis cranii, and FIGURE 1.—Dicynodon sollasi Broom. Right side. Natural size. are mainly situated just behind the internal nares. There is certainly a long interspace between the basisphenoid and the vomers and this space is occupied by the pterygoids. Therefore I can not adopt the interpreta- tion of the paired vomers being in fact the parasphenoid. On the con- trary, the true parasphenoid is present in the major portion of the rostrum basisphenoidei. It is useful also to compare the sections given by Sollas. It is quite true that the parasphenoid may extend for a considerable distance anteriorly and that the vomer may extend far posteriorly, but the main region of the parasphenoid is below and imme- diately in front of the basisphenoid, and the main region of the vomer THE IMPORTANT FACTS A461 is in the neighborhood of the nasal capsule, originating on the ventral side of the paraseptal cartilage. The vomer in Dicynodon certainly ap- pears to be a paired bone, and its relationships are lke those in the mammals. The rostrum of the basis cranii I could not imagine as being the mammalian vomer. FIGURE 2.—Dicynodon sollasi Broom from below. Natural size. Bo = Basioccipitale. P] = Palatinum. Bs = Basisphenoid. Pm — Premaxilla. Ch = Internal nares. Po = Postorbitale. Ko = Exoccipitale. Pof = Postfrontale. Ep = Epipterygoid. : Prf = Prefrontale. F. c. = Foramen carotidis. Pro = Prooticum. F. p. = Foramen parietale. Ps = Presphenoid. F. vy. = Fenestra vestibuli. Pt = Pterygoid. F. V. = Foramen vagi, etc. Q = Quadratum. J = Jugale. Qj = Quadratojugale. I. Pt. = Interpterygoidal space. Sm — Septomaxillare. L= Lacrymale. Sq = Squamosum. M = Maxilla. T. Bo. = Tuber basioccipitale. N = Nasale. Tr. = Transversum. Opo = Opisthoticum. V = Vomer. P= Parietale. Z = Tooth. Pa = Parasphenoid. The distribution of the bones on the ventral side of the skull of Dicynodon (and also of all Theromorpha) does not differ greatly from that of the same region in the later reptiles, the Archosauria, as well as in the Stegocephalia and also in the mammals. Some of the earlier de- 462 ¥F. VON HUENE—THE VOMER-PARASPHENOID QUESTION scriptions of the theremorph palate seem to indicate quite a singular pattern, but I hope that after accurate investigation the arrangement and interpretation of this region in all theromorphs will turn out to be the same as in this Dicynodon skull, which quite agrees with the archo- saurian type. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 463-468 SEPTEMBER 30, 1923 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY LINES OF PHYLETIC AND BIOLOGICAL DEVELOPMENT OF "THE ICHMT YOPTHRY GLA * BY F. VON HUENE (Presented before the Paleontological Society December 30, 1922) CONTENTS Page SEO TPT ESE E HIT IED 5 Spe le REA Se Po ein nc SIS ee SE nae a Rea er ee a eee era 463, DSSS. SETS VE a ga 2 ee ne en age ee a a ae AGR nA NI ACAI SAIC ES se een ue alae Sec aint niin ni bie ¥ mf LRTS elo reiet s wlan OMS 2 oe. yt A eed 464 iran And) One TpIMMAWOee oe cs le oes oe ei de oc nce eee ee we sees 465 INTRODUCTION The great order of the Ichthyopterygia, known from Permian to Upper Cretaceous times, is formed by the Ichthyosauria, Omphalosauria, and Mesosauria. A special study of all Liassic Ichthyosauria from the English and German Lias led me to a synoptic classification, which has also extended over all Jurassic and Cretaceous forms. Those of the Triassic are al- ready well known from the classic memoirs of Merriam. Through recent additional observations of the extensive Mesosauwrus material at Tubingen (from Brazil) this group may be reinterpreted and reviewed. Therefore it is possible for the first time to form an idea of this highly diversified and long-lived order of the Ichthyopterygia.? MESOSAURIA I need not repeat the reasons why the Mesosauria can not possibly be the forerunners of the Ichthyosauria,* but many features in the skull and skeleton demonstrate convincingly their common origin. The Mesosauria 1 Manuscript received by the Secretary of the Society March 15, 1923. 2F. von Huene: ‘‘Die Ichthyosaurier des Lias und ihre Zusammenhinge.’”’ Ed. by Gebriider Borntraeger, Berlin, November, 1922, vii, 114 p., 22 pls. Quarto. 3N. Jarhb. f. Min., etc., 1910, ii, pp. 29-69. (465 ) 464 ¥F. VON HUENE—DEVELOPMENT OF THE ICHTHYOPTERYGIA are, it appears to me, a primitive short side branch of the theoretic main line leading to the ichthyosaurs. This primitive group, which has not yet been found in the Permian, but which certainly existed in that epoch, must have been a parallel branch with the Cotylosauria, both having sprung from the Carboniferous Embolomeri. The evidence for this is given in detail in the paper cited above. FIGURE 1.—Neuw Restoration of the Skull of Mesosaurus braziliensis from the Permian of Irah, Brazil Natural size. From specimens at the University of Tiibingen. Bo = Basioccipitale. Pal = Palatinum. Bs = Basisphenoid. Pm — Premaxilla. Jug = Jugale. Pt = Pterygoid. Mx = Mazxilla. Q = Quadratum. N = Nasale. Vom = Vomer. ‘ No = Internal nares. OMPHALOSAURUS Omphalosaurus is a coastal remnant of rather primitive Ichthyosauria, which have not yet become so well adapted to marine habits as have later forms. Both Mesosauria and Omphalosauria exhibit marked evidence of pachyostosis, according to Nopsca,* and are therefore on the way toward aquatic adaptation. * Anatom. Anzeiger, 1922; Paleont. Zeitschr., v, 3, 1922. Both papers are still in press. THE TWO MAIN LINES 469 LATIPINNATID® AND LONGIPINNATID@ In the Triassic the Ichthyosauria already appear, divided into two main lines, the Latipinnatide and the Longipinnatide. The first known latipinnatid is Mixosaurus, from the Muschelkalk. Its direct descendant in the Lower Lias of England is the genus Huryp- terygius (Jaekel), with the well known species £. communis, interme- dius, and others having ribs with divided heads and pelvis consisting of three separate bones. In the Upper Jurassic the latipinnatid group is represented by several new genera: (1) Macropterygvus (— group of I. trigonus, with extremely large paddles, ribs as in Ophthalmosaurus, pelvis consisting of three separate bones, trunk long, tail short, teeth covered at the root with a mantle of cement), which is continued into the Middle and Upper Cretaceous (until Senonian); (2) Myopterygius (= campylodon group, in some respects similar to the former, but with enormous trochanters on the humerus and femur, and with differences in the skull) ; (38) the well known Ophthalmosaurus (incl. Baptanodon) (antermedium between radius and ulna, vertebral column and ribs sim- ilar to Macropterygius, pubis and ischium coalesced) ; (4) Brachyptery- gus (extremus, only radius and ulna in contact with the humerus, but with large sesamoid ossifications on both borders of the paddle, beginning at its proximal end). The longipinnatid line, beginning with Cymbospondylus in the Middle Triassic, is still more highly varied than the latipinnatids, but more so in the early Mesozoic. In some respects Cymbospondylus is still more primitive than Mizosaurus in the proportions of the body, which has (as compared with Jchthyosaurus) an extraordinarily small head and very long and large paddles, especially the posterior pair. All the different shastasaurids have a short hfe and a rapid development. One lne, which can not be included in the shastasaurids, but is related to this group, extends into and through the Lias. For this group I have proposed the generic name Leptopterygius. Some Rhetic forms, and the well known species I. platyodon, lonchiodon, tenwrostris, etcetera, of the Lower and acutirostris and integer of the Upper Lias, constitute this genus and are characterized by proximally undivided ribs (but nevertheless with two articulations) and by three separate bones in the pelvis. A special form of this group is Hwurhinosaurus (Abel) longirostris in the Upper Lias. So the whole of this highly diversified main line of the Longipinnatide does not extend beyond the Liassic, and even in the Triassic has dis- appeared almost entirely. XXXI—BULL. GEOL. Soc: AM., Vou. 34, 1922 466 ¥F. VON HUENE—DEVELOPMENT OF THE ICHTHYOPTERYGIA Senon Turon Cenoman Apt unt Kreide “yopterygius Malm y) s x 3 Li) re) Lo) = >) a= Ss = co) Macroplery gius S, [ch Ge “Ory ois \ Nannopterygius “ a ae Oa Serie Smee es - 7 —-—---=- oa Dogger i GUUS es ob. Lias Stenoprer mittl.Lias & % ! > s) X unt Lias Rhaét Keuper Lettenkohle Muschelkalk Mixosaurus Buntsandstein Perm Carbon Figure 2.—Scheme of the phylogenetic Development of the Ichthyopterygia THE TWO MAIN LINES A67 There are, however, other longipinnatids which are still rare in the Triassic (I refer especially to Toretocnemus, with ribs much divided proximally), but which branch out in the Liassic and later form Stenop- terygius, including quadriscissus and many others. These animals are very perfectly adapted to a swimming mode of life, no less than are the contemporaneous latipinnatids. Throughout the Upper Jurassic forms are found with very small paddles and exceptionally strong tail (the functions of which compensate each other) of the group Ichthyo- saurus euthecodon. I have proposed for them the new generic name _ Nannopterygius. There is a form in the Middle Cretaceous described by Broili as I. platydactylus, which has specialized in another direction. This form has very broad paddles, with sesamoid bones at the anterior and posterior borders. The tip of the tail was short and the animal was probably therefore a very poor propeller. This genus I call Platyptery- gus. It is the latest latipinnatid known. Land tetrapods when first adopting aquatic life row with both pairs of extremities, a condition seen in the Mesosauria. The better adapted they become to that mode of locomotion, the more the function of the hind limbs is emphasized (as, for instance, in the crocodiles). This is still seen to some extent in one division of the Longipinnatide, namely, Cymbospondylus, the shastasaurids and Leptopterygius. Originally the slender, long-tailed bodies of the unknown earliest ichthyosaurs prob- ably swam with a natural serpentine motion. By and by this was found useful for propulsion and became more localized in the flexible tail. In the same degree the neck was shortened and the head enlarged. This must have been true of all Ichthyosauria, but to a greater extent in the branch which later became the Latipinnatide. The function of the tail must very early have become one of propulsion, and at its strongest point a fin border (“Flossensaum”’?) was acquired, later developing into a more or less symmetrical diplocercal caudal fin for a propeller. For a long time the paddles remained as organs of propulsion, and were used for that purpose in most of the earlier longipinnatids, but in the Stenop- terygiwus branch and in all later longipinnatids, as well as in all latipin- natids, the hind paddles became. reduced because of the perfect function of the tail-propeller and the fore paddles became more and more en- larged for vertical steering and for balancing. In the fore paddle of the latipinnatids the number of digits is not reduced, as it is in all longi- pinnatids. This’may be explained by a differentiation in the very earliest mode of adaptation, when the two main divisions of the ichthyosaurs were just forming. In swimming, the upper wing of the diplocercal caudal 468 F. VON HUENE—DEVELOPMENT OF THE ICHTHYOPTERYGIA fin, being immobile, together with the dorsal fin, functions as a rudder. The wriggling lower wing of the caudal fin acts as a propeller. In the later Mesozoic ichthyosaurs the trunk becomes relatively longer and the anterior half of the tail is shortened. Therefore the whole body becomes more torpedo-like and better adapted for swimming, as in the modern AXiphias gladws. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 469-494 SEPTEMBER 30, 1923 Is THE CHANNEL OF THE MISSOURI RIVER THROUGH NORTH, DAKOTA OF TERTIARY ORIGIN? BY JAMES E. TODD (Presented before the Society December 29, 1921) CONTENTS Page NMHSONA INCH ORME Pal t Teonit egos Msteen Yh Sash alle! AML cet nN ais tet he SicTa a ‘so 5 Alaa geo eee! oa & 470 ES MREUERV AES COMM CEILS ays teas ceei ena c, wie jake ace sau oedsacbercumreielan doze gere © eta tadue MNS) s ske nies 470 PirerOrmmeoOnard OL (tae nehiPOIa hive. 3/3. acca ais « sags WslecGcs © Genweyad os ere EO Met MOMMO Lean AUTOM ES ei ean daha elo Seip licts eS ook ob b vavene pe cab oie nies 473 Pe seonard is, areuments. Inadequate 4.5.5. oib wea oe cw wesc ewe ee ol 473 EMEC Oe ONO CM AMES. jc sae goatee baie. c) a isever ads Fak boh ee cess ene bie lo ote ou 473 Siact ue DOUlMersS Meal oR ISMVAECK 2.2.25 be sol ee oe cab ees eda ew eoodieend 474 eID Rea MeLS Min TOLMA CES aise i. slave eon ane ee claw cles Shrenlencscioeewe das 475 Sesser nil pagum oy Poeedett oh ti EY Pa ee eke ha Silks panei sale pane AT5 Boulder bar near mouth of Tobacco Garden Creek...:.............. 475 pe Mes wEE OMA SOUL MY AK OWA 2 «seo siete aeele Sisicis Give ss Gc vt ccs devas wwlcd ee « 476 Sree Mer Stei emi tei wer tn OR MAT ire Bone) si talaviote a aeeetes iW aes Ho sec ceed Mises bac AT6 Demin non uae yNiobrana (Ravers. 14.004 oo cli Sd eles we ooo ee be noes 47S ease IDEA UNS Ona CE eaested. aeatue ra ela ohh als aod duc chee ee wok A alles s Oem wwe ATS JSPOEE LS UUUITS GUIS AUCG (CR ERE Sa onl eee ga ae ea ee RD er Pe a 479 MP MICeMPAUI IAT OO 85222 cries hc. oth ha ews PRE Bs AG OR ie aR 479 Sacral DOMlGenrs. without. sac ak ya ce oe kooks oo kde oes eck A479 (PILES 2g, Soe ea ected Te aa ata SD eS oe au AeA aa ne 483 LE STTLENSTONCS: TECH ESS RW LOT ETT 0 ec an pan eR eg 486 Seeeottcr tect eerste EMO Mew erine mip ee on eu Duo Oa oe Beta ails 486 Resale eN AM PCT O SOME y tae tenn s nts nck Pear scat Sie t, f ee en ce 486 Dithiculiye or removime drift, from channels, . cis 00. oo oc ee ek 486 The Yellowstone and Little Missouri diverted from their Tertiary SAMUI Serer Pe Kis en NNER oR mane Me et a eke eee baralpeseete cers AST See MEMO leon CCM EGS 14 aie tea ede hk Cites. wo ae eae hee ee ee 487 Provisional history of the origin of the Missouri in North and South ILOSIIRO TEs Re ey rec RET PEN eae Bele en Dope Komitee ter shar ehae San aks wale Soe Sik oak 488 SPE IG IOE Ub S52 CELIO NS eine Pet URI “ORGAN cea igs 00 ct Sa a gn 488 Glacial activity increases with temperature........................ 489 During the- advance of the Wisconsin ice-sheet..................... 489 iiee Niobrara Eiver and Red lake... 2...) ....<.. ce eee nek 490 LERIEACES: 6c bio loie eieigrl We hIt ks et peat eo eta et is an 491 1 Manuscript received by the Secretary of the Society June 16, 1922. (469) A470 J. E. TODD—_THE CHANNEL OF THE MISSOURI RIVER Page Head \ croston:) PRONTNENE. 3-324 0S wn Oe oP es eee ee ee pet ee 492 The Bie Berthold (bem. 322: ns 0.4- eee eeeee e Seee eee oe 492 INTRODUCTORY For years it has been believed that the Missouri River owed its present course very largely to the influence of ice-sheets. This was first recog- nized by General G. K. Warren in 1868. In 1916 Prof. A. G. Leonard, State Geologist of North Dakota, published his conclusion, after some years of study, that the channel of the Missouri through North Dakota was of Teritiary origin, and that the ice-sheets of the Pleistocene had little effect upon its course. This conclusion is diametrically opposed to that of South Dakota geolo- gists; consequently the writer undertakes in this paper to show the errors of Dr. Leonard and, on the contrary, the reasons for believing that before the ice-sheet influenced the Missouri River the Missouri was made up of various streams leading to the north and east, and that the ice, by damming them, caused the water accumulating along its western edge to form a series of lakes and channels which eventually determined the present course of the Missouri of the Pleistocene in the Wisconsin stage. ACKNOWLEDGMENTS The material for this paper has mostly been gathered incidentally during several seasons’ work, years ago, for the United States Geological Survey and for the South Dakota Geological Survey. More recently the Chicago, Milwaukée and Saint Paul Railway Company presented me with profiles of their lines west of the Missouri River in South Dakota, and the Minnesota and Saint Louis Railroad Company did likewise with their lines to Leola and Le Beau. I am most grateful to Messrs. Norbeck and Nicholson, well-drillers, Redfield, South Dakota, for the free use of an auto and chauffeur for a week in Cheyenne River Indian Reservation. The writer has not been personally familiar with facts concerning the Missouri above Bismarck and has depended almost entirely upon the reports of the North Dakota Geological Survey and a few articles in geological periodicals. Dr. LEONARD FOR THE AFFIRMATIVE Dr. Leonard, in his paper before the Geological Society of America, gives his reasons so clearly and concisely we quote them in full. We MAP OF NORTH DAKOTA A771 have inserted numbers to indicate the different arguments and also for reference.” 1. “The valley of Snake’ Creek is no larger than the valleys of other tribu- taries entering the Missouri above this point, and the notch in the east front Limit of the glacial drift Edge of moximum ice sheet vv. | PLE! ae . Altitude, feet above sea leverm |_ Scale in miles 22 #220 _30 | FIGURE 1.—Map of North Dakota ' Showing probable history of the formation of the Missouri River in North Dakota. of the divide north of Fort Stevenson, which is shown on some maps, does not exist in reality, and there is no evidence of any preglacial valley here. The valley of Long Lake Creek could hardly have been the eastward exten- sion of the Cannon Ball River valley, since its lower course is not opposite 2 Bull. Geol. Soc. Am., vol. 27, p. 295. AT? J. E. TODD—_THE CHANNEL OF THE MISSOURI RIVER the mouth of the latter stream, but joins the Missouri four miles to the north. There is no reason for believing that the Knife River ever joined the Missouri near Fort Stevenson, and the lower valley of this stream has every appearance of great age, having a broad floodplain’ and gentle slopes. It is clearly a preglacial valley. The Heart River is thus the only important tributary of the Missouri which might have continued eastward to the James River if the valley of Apple Creek, which has its mouth just opposite the Heart, is av indication of this. But Apple Creek is readily accounted for as a preglacial tributary of the Missouri and one of the chief outlets for the glacial waters when the ice-margin occupied the position marked by the Altamont moraine. Its valley is largely filled with glacial outwash from the moraine.” 2. “There is abundant evidence that the Missouri Valley below the mouth of Snake Creek is preglacial, and that the river was not forced by the ice- sheet to take its present southerly course through North Dakota. This evi- dence is based on the presence of glacial boulders on the valley bottom and at Many points cn a terrace representing a former floodplain of the Missouri. Boulders have been encountered in two wells in Bismarck at a depth of 125 feet below the surface or 80 feet below river level. These wells are near the edge of the terrace bordering the Missouri Valley at Bismarck, and since the boulders rest on the bedrock they indicate that the valley was excavated to this depth prior to the Glacial period. In several borings made for the Northern Pacific Railroad previous to the building of its bridge across the river at Bismarck, from 70 to 80 feet of silt and gravel were passed through before reaching the bedrock, and in one boring a boulder was struck at a depth of about 50 feet below the river bed.” 3. “On the west side of the Missouri Valley, between Mandan and the mouth of the Knife River, there is a well developed terrace which in places is a mile and more wide. This terrace has an elevation of 55 to 60 above the river and the upper portion of it is in many places composed of glacial gravel and good-sized boulders. iaurk 6.—View of Portion of bouldery Margin of Lake Arikaree, with Virgin Butte in the Background The view is looking a little north of east. Just beyond Virgin butte is the old outlet which formerly drained Lake Arikaree down the valley southeast, now occupied by Stone Creek and Virgin Butte Creek. The country to the right and back of the river is almost strictly driftless, There is a gradual rise farther south into Rox Ridge, 486 J. E. TODD—-THE CHANNEL OF THE MISSOURI RIVER EVIDENCE FROM MONTANA GENERAL STATEMENT The Missouri River in its course throughout that State has been related — to the ice-sheet on the north and the driftless regions on the south, sim- ilarly to that which we have noted in North Dakota and South Dakota. Moreover, the history of the ice-sheet seems to be very similar to that in North Dakota. There is found in both cases till-covered areas outside of the Altamont moraine. This till may be of Kansan age or of early Wisconsin. The most recent stage of the ice was that of the Wisconsin at the time of the formation of the Altamont moraine. This general relation is similar to that which we have recognized in South Dakota and of course argues that similar might be expected in North Dakota, the State between. That the valley was Tertiary is indicated by the geological section at Glass Bluff,* 4 miles southeast of Buford. “Glacial drift, 25 feet,” lies more than 160 feet above the Missouri,® or 2,100 feet above tide. This agrees well with the “Benny Pierre-Hay Draw” outlet, 2,200 feet above tide. Afterward the Yellowstone became a component of the Missouri , and cut down its present channel. POSTGLACIAL EROSION Dr. Leonard has concluded that the erosion of the Missouri River along its present course is too great to have been accomplished by that stream since the beginning of the formation of the Altamont moraine. The erosion at its greatest is not more than 500 feet in depth and a mile or two in width. From Montana we find that the erosion from the Missouri channel from Mussel Shell River to Milk River is from 600 to 1,000 feet. In the former case the material eroded is mostly clay and soft sand. In the latter it is consolidated sandstone. Below Great Falls the Missouri has been flowing over sandstone, so that it is readily seen the postglacial erosion is 150 to 250 feet in depth. Another point is that the preglacial valleys in a number of cases, especially toward the west, are cut very much deeper than those of postglacial origin. This is prominent in the case of an old channel of the Missouri near Great Falls, which by boring near Sand Coulee was found to be 270 feet deep.2° DIFFICULTY OF REMOVING DRIFT FROM CHANNELS From the map on page 38 we see how the erosion of a drift-filled chan- nel seems very little, if any, affected by harder rocks for the walls of the ‘ Third Biennial Rept., N. Dak. Geol. Suryv., p19: * Bull Geol. Soc. Am., vol. 27, p. 300. 10 U. S. Geol. Sury., Professional Papers, No. 50, p. 36. EVIDENCE FROM MONTANA A487 valley. How much less, therefore, when both walls and filling are un- consolidated, as in most of the Dakotas. THE YELLOWSTONE AND LITTLE MISSOURI DIVERTED FROM THEIR TERTIARY CHANNELS Mr. Calhoun, from a study of the Keewatin deposits in Montana, traces the preglacial valley of the Missouri to Glasgow, on Milk River, and from quotation from others shows that it continues on to the northeast corner of Montana, and the Little Missouri likewise shows similar points in its history. “Tn the late Tertiary,” according to C. M. Bauer,’* “it occupied a well- marked channel extending northward from the first prominent eastward bend of the present stream to the head of Tobacco Garden Creek and thence along this valley to the present Missouri,” he adds, “to the Ter- tiary Yellowstone near Williston.” More likely the Tertiary Little Mis- souri crossed the Missouri near the mouth of Tobacco Garden Creek and ran north several miles farther before reaching the Yellowstone. During the maximum of the ice all three streams joined in a lake and for a time flowed eastward over the mid-course of the smallest stream. Eventually the Yellowstone and Missouri ceased to rise to Benny Pierre- Hay Draw. outlet, but found the course of the present Missouri River, the Little Missouri determined by an outlet of the lake. The Missouri and Yellowstone, on the withdrawal of the ice-sheet, found themselves in well-defined valleys from Poplar and Glendive respectively to Williston. The most plausible explanation of the new channels is that they were eroded by subglacial and preglacial streams during the advance, the culmination, and earlier recession of the early Wisconsin. Head erosion we deem to have been particularly efficient during the recession of the ice. It was a time of rapid deposition of stratified drift. SUMMARY OF EVIDENCE All of the arguments presented by Dr. Leonard for the origin of the channel of the Missouri as being preglacial or Tertiary are found to be negative or indecisive. In other words, the case as he presents it is not proven. ) _ The first positive argument for the glacial and Pleistocene origin of the Missouri channel is the evident relations of the latter to glacial dis- tribution and deposits. This argument is especially strong if no other theory is capable of explaining the facts. Dr. Leonard gives us no reason 4U. S. Geol. Surv., Professional Pavers, No. 50,-p. 31. 2 Journal of Geology, vol. 23, p. 55. 488 J. E. TODD—-THE CHANNEL OF THE MISSOURI RIVER . for the anomalous relation of the Missouri to the general slope of the country, namely, that the general course is nearly parallel with the strike of the slope of the surface instead of with the dip. This argument will stand, and the burden of proof les on the other side. The presence of stratified drift in the higher portions of the valley, together with the absence of till at lower levels of same, is strong evidence that the valley is glacial or postglacial in formation. If streams flowed at higher levels, they show the altitude of the plane of drainage at that time, and the absence of till at lower levels proves that the lower portion of the valley was not excavated ; for we can not conceive of the lower por- tion being filled with drift, especially till, and later have it all removed. The very nature of the case forbids it. An analogy with the cases studied in South Dakota and Montana strongly argues for the Glacial or Pleistocene origin of the valley of the Missouri in North Dakota also. PROVISIONAL HISTORY OF THE ORIGIN OF THE Missouri IN NoRTH AND SoutH DAKOTA GENERAL STATEMENT In this portion of the course of the Missouri it is crowded by the edge of the Wisconsin ice-sheet on the left from near its origin in Montana to the southeast corner of South Dakota. On its right side there lies an area over which the Wisconsin ice-sheet never passed. From Niobrara eastward, where the river forms the boundary of the State, there is a till- sheet formed by an older ice-sheet which extends over many square miles southward into northeastern Kansas. This is known as the Kansan ice- sheet, which is judged to be much older than the Wisconsin. In South Dakota no boulder-clay or till has been found west of the Missouri, although it is not unlikely that closer search may show con- siderable of the Wisconsin till outside the Altamont moraine. In North Dakota there are a few small patches of till lying 40 or 50 miles to the west or south of the river. In northeastern McKenzie County a portion shows not only patches of till of moderate thickness, but also distinct moraines. In the western part of .Montana, near the Highwood Moun- tains, there is a moraine 50 to 100 miles in length and so continuous as to change the course of streams in the vicinity. The general course of the moraines, both older and newer, is northwest. Dr. Dawson, of the Canada Survey, considers the older drift deposits and moraines next west of the Wisconsin stage in Canada to be Iowan. Tyrell, of the same Survey, considers them Kansan. Calhoun considers PROVISIONAL HISTORY OF ORIGIN OF THE MISSOURI 489 the older deposits there to be early Wisconsin.** Leonard considers the older drift in North Dakota, especially that west of the Missouri, as Kansan, but also recognizes till east of the Missouri, outside the Altamont moraine, to be early Wisconsin. It seems not improbable that some of the morainic drift west of the Missouri belongs really to the early part of the Altamont moraine, as, for example, in eastern McKenzie County. It is generally agreed that the ice which was concerned in this case was also from the Keewatin center west of Hudson Bay, and that it was of the Wisconsin stage; and it seems probable that considerable of the drift outside of the Altamont moraine is to be included also under the term “early Wisconsin,” and that the great prominence of extra morainic till in Montana, and to a less degree in North Dakota, is to be attributed to the lower temperature of the ice at that higher latitude. GLACIAL ACTIVITY INCREASES WITH TEMPERATURE A principle that is generally recognized is that higher temperature promotes greater activity in glaciers—that is, that the velocity is much greater in summer time than in winter time. Moreover, much more water is discharged in all streams supplied with water from the ice, forcing them to put on a. torrential phase with maximum. A corollary from this principle would be that glaciers on the south tend to receive more heat, and consequently move more rapidly on that side. For some- what similar reasons glaciers seem to be more active on their south and west sides because of the greater influence of the sun’s heat. DURING THE ADVANCE OF THE WISCONSIN ICE-SHEET It will be readily seen that, so far as North and South Dakota are concerned, the ice approaches them from the northeast, and it is evident that it must have moved more rapidly in a southward direction; so that it may have, perhaps, reached the southern line of South Dakota nearly as early as the western part of Montana, and that its appearance opposite the angle northeast of Bismarck may have been considerably earlier than at the points already specified. At any rate, we may suppose that the age of the Altamont moraine is about the same throughout, although older ~ portions—that is, near the outside and at higher levels, unless apt to be removed—may have been accumulating hundreds or thousands of years earlier than the inner portion of the same moraine. | Previous to the formation of the Altamont moraine, we may suppose that the valleys of all streams flowing north or east would become ob- 1%7U. S. Geol. Surv., Professional Papers, No. 50, p. 52. 490 J. E. TODD—-THE CHANNEL OF THE MISSOURI RIVER structed or dammed by the ice and changed into lakes, which would fill rapidly, not only from the glacier, but from the rainfall of regions farther west; so that in a short time each prominent river basin would contain a good-sized lake. Because of the eastward slope of the country, these different lakes would become deeper first next the ice, and the connecting streams escaping from the lakes would be first in the close vicinity of the ice. We may suppose that the line of lakes in both of the Dakotas would have several phases of development with each particular stage, but more or less contemporaneous through them all; and yet it would take longer for a large lake to pass through certain stages than a smaller and simpler one. THE NIOBRARA RIVER AND RED LAKE In the early stoppage of the stream we may suppose that the Niobrara River and Red Lake may have developed more promptly, although they may have begun later than the lakes farther north. They were able to cut through their respective barriers more promptly, and thus prepare the way for the draining of the lakes farther north. It is probably unnecessary to attempt to give the lakes in detail or in order, referring instead to the maps and remembering that the phase during the old history must have changed frequently. It may not be necessary to do more than call attention to some more striking points. We find evidence that the Yellowstone and the Missouri west of the Little Missouri became dammed by the ice on the north, which caused an overflow into the valley of the Little Missouri. . Leonard has assumed that the valley of the Little Missouri was Pleistocene, whereas we take it that its Tertiary channel was by way of Tobacco Garden Creek and northward until it found the Yellowstone. When the ice advanced, it : dammed the course of the Little Missouri and formed a lake, which received water for a time from the Missouri River and the Yellowstone through the Benny Pierre-Hay Draw outlet. The outlet of Little Missouri Lake was along the present course of the Little Missouri eastward. Patches of numerous boulders are found here and there marking the course of the Little Missouri around northeast and south of the Kildeer Mountains. Probably at its early stage it emptied into Knife River Lake, this lake in turn passing over into Heart River, and so on southward into Lake Arikaree. An old shoreline of this lake seems to have been the origin of Farmers Valley and of the escarpment south of it. As the lakes had their outlets cut down more and more, one marked effect would be that these outlets would be on the side next the glacier, for not only would the slope of the country tend to throw them farther east, but also the streams on that side would be much more PROVISIONAL HISTORY OF ORIGIN OF THE MISSOURI 491 active and prevalent, and therefore their head erosion much more rapid. Eventually the lakes became less extensive, and as the ice withdrew to the east again the lakes in general would become filled and drained until they disappeared. The effect of the ice withdrawing to the east- ward would be to uncover more lake area lying adjacent to the front of the ice. The explanation of the larger streams lying not far from the perma- nent and larger moraine, known as the Altamont, is to be found in the principle already mentioned, that the head erosion is particularly active in the streams immediately supplying water from the ice. This explains why the present course of the Missouri was located quite early. This became permanent before the withdrawal of the ice from the Altamont moraine. In short, the waters from the moraine eroded quite rapidly, because the coarse material was dropped next the ice, so that erosion was accelerated at a short distance outside of the main deposition. We con- ceive of the Missouri cutting down deeper and deeper during the Pleisto- cene, excavating what Dr. Leonard has called “the preglacial valley.” This reminds us of a point of which we have said little, but which in its combined effect serves as a powerful argument for the similar origin of the Missouri in all three States under consideration. TERRACES In the valleys of the Missouri and its principal tributaries, there are many very striking river terraces. These terraces are mainly the result of erosion, the lower part of them being composed of bedrock and the top composed largely of coarse material, mainly from glacial drift, the finer silty material being largely washed away. A general statement applying to all these terraces may be given as follows: They vary in altitude above the principal stream from 20 to 450 feet. Those lower than 20 to 40 feet show few boulders and are known as “silt terraces’ or “second bottom.” They probably mark the erosion which has taken place since the disappearance of the ice. Those above 100 feet are usually largely composed of boulders in the upper portion. These boulders are the larger and more conspicuous, from 200 to 300 feet. _ These upper ones are called “boulder terraces,” and without doubt mark the intensity and altitude of erosion at different stages in the early Wis- consin stage. These terraces are as near level as usual under such cir- cumstances, except for several miles below Bijou Hills, where some of the terraces show a much steeper slope down the stream. This uniform arrangement corroborates more strongly the idea that the history of the streams in these three States have been unusually uniform. Not only 492 J. E. TODD—-THE CHANNEL OF THE MISSOURI RIVER does it emphasize the similarity of the conditions of the different streams, but the different areas are parts of the same system; so that we can not conceive of one portion being cut down without the subsequent lowering of all connected with it. Hence it is inconceivable that Lake Arikaree could have drained until Lake Niobrara had cut down; in other words, not before the Pleistocene. On the other hand, we can not believe that the valley of the Missouri in North Dakota could have been excavated or formed during the Tertiary without excluding the Yellowstone and the Little Missouri on the one hand or the Cannon Ball on the other. We conceive that the erosion of the valley of the Missouri had cut down within 400 or 500 feet of its present level by the advance of the ice to form the Altamont moraine.. This would correspond to the boulder- topped terraces spoken of in connection with the Little Missouri and elsewhere. In the maximum extent of the ice, we find the time when the Pleisto- cene channels were first occupied—for example, the outlets of varicus lakes—and the lower boulder terraces mark the latest direct effect of the Altamont moraine upon the stream and its deposits. HEAD EROSION PROMINENT We have already alluded to the prominence of this function of streams, but we find it especially prominent in the history of this region. It has been especially the cause of the various streams approaching the Altamont moraine. While there may be traces of portions of the Tertiary courses of streams still occupied and later of Pleistocene courses, the portions of streams next the moraine which together form the present course of the Missouri have been formed by this action of streams, namely, head erosion. ‘To illustrate, we have the Tertiary course of the Little Missouri marked from its eastward bend to the mouth of Tobacco Garden Creek. The course from the bend eastward would be of Pleistocene origin, prob- ably during the maximum extent of the ice, and probably the earlier part of it was a lake which soon became drained. The course of the Missouri from the mouth of Tobacco Garden Creek to the presént mouth of the Little Missouri would be an example which was formed by head erosion and was probably not continuous and prominent until the latter portion of the Wisconsin. THE BIG BERTHOLD BEND What seems a unique but unmistakable example of this is illustrated in the Great Bend in Fort Berthold Reservation. It has already been suggested by several observers of that region that the curve of the great U-shaped bend marks the position of a moraine formed around the south- PROVISIONAL HISTORY OF ORIGIN OF THE MISSOURI 493 western tip of a local ice-lobe, and the straight valley reaching across the top of the U is the bed of the preglacial course of the stream, and that in some way this straight valley—which, by the way, is more than 100 feet higher than the present river and slopes downstream—became filled by ice in the advance of the glacier which formed a bridge for the onward motion of the ice. The suggestion is perhaps insufficient and presents several difficulties which we need not stop to consider. Mean- while the water of the stream above the U found its easiest pathway to be around the outer rim of the moraine. The head erosion acted along the more vigorous course of the water, namely, the outside of the moraine, until they completely connected the channel below with the channel above this U-shaped bend. This is a very unusual example of head erosion, the general tendency being rather to cut off bends than to form them. A ~ * portion of the ice may have fallen below the pressure of the ice behind and remained stationary, like a boulder pavement, except the stationary lower mass was ice instead of till. The rest of the glacier passes on to form the moraine. One fact favorable to this view is that the cross-valley is at right eee to the direction of the ice movement or the course of the glacier. In conclusion we note that from whatever direction we have approached the region we have been considering, we find that the present course of the Missouri River is more recent than the Tertiary and earlier than the end of the Pleistocene, or more dennitely during the Wisconsin Stage of the Glacial period. Moreover, we have been reading one of the most interesting chapters of glacial history, but let no one think that we have been reading the most interesting. We know no reason why the stream changes were not as numerous and striking in the Nebraskan or the Illinoian as we have found them to be in the Wisconsin. eb ‘ é ‘ H Pea { Sih wr ri P 'e ir ay iS > 7 é: yes f ea, ar ™~ wif f 7:40 -at! , i A Fiat & 6.0% + ¥ i oa % ; m ah: i * : ! ip wire ‘abit Lee ePaitey i 4 hata oe f <4 boy F r a i yi te BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 495-498 SEPTEMBER 30, 1923 ’ MERGING OF CARLILE SHALE AND TIMPAS LIMESTONE FORMATIONS IN SOUTHEASTERN COLORADO! BY HORACE BUSHNELL PATTON (Presented before the Society December 29, 1922) CONTENTS Page RATAN OED ee rep tere Sc eins. 82S alae ee REE eS Anan as Rie Sel eAe ics Sh sb. 8 ee ee 495 Cen OTe! METI 5 sicalsiic 1c, v2h ous nieces oe eenmye'e; sieleln # ee os yee SA eae 497 Pate OSs inate: Dimpas. TMMESLOMEs viccxeyis cla fee eos we ee ec ee eee es 498 INTRODUCTORY In connection with field-work undertaken for the Colorado Geological Survey the past summer in the vicinity of La Junta, Colorado, the author has had occasion to note a gradual transition or merging of two forma- tions that heretofore have been considered as belonging to two different groups, the Benton and the Niobrara groups. The present communica-- - tion is presented with the consent of the Director of the Survey. In southeastern Colorado the Benton group is developed as three readily distinguished formations. The lowest of the three is the Graneros shale, with some 200 feet of gray to black shales. The highest, or Carlile shale, has usually about the same thickness and is likewise composed of dark gray shales, which at the top change to a yellowish sandstone of 20 feet thickness or over. The two are separated by some 50 feet of Green- horn limestone. The Niobrara group Has a twofold division—into the ‘Timpas limestone at the bottom and the Apishapa shale at the top. The two together have a thickness of some 700 feet, of which 500 feet belong to the Apishapa and 200 feet to the Timpas. The upper 150 feet of the ‘Timpas are composed of gray shales with occasional thin beds of white limestone. The lower 50 feet consist of massive beds of soft, almost chalklike limestone, one to two feet thick, separated by very thin shale partings. The contact between the basal limestone of the Timpas and the underlying top sandstone of the Carlile shale is usually very sharp. 1 Manuscript received by the Secretary of the Society December 30, 1922. (495) 496 H. B. PATTON—CARLILE SHALE AND TIMPAS LIMESTONE Apishapa 500° Concretions Niobrara Shales Shales and thin Timpas limestones 200' White chalky lime- stone 60' Transition bed between Benton and Niobrara 3 Carlile Concretions 130" Shales Greenhorn Limestone and shale 60' Benton Graneros ; Shal 200 tet FIGURE 1.—Part of general Section in which Transition Bed occurs CHARACTERISTICS OF UPPER CARLILE MEMBER 497 THE Uprer CARLILE MEMBER In writing of this Upper Carlile member, Darton? says: “At the top there is a bed of sandstone varying in thickness from a few inches to 20 feet, the amount increasing to the west. . . . The top sand- stone averages 10 to 20 feet in thickness west of longitude 104 and attains a maximum of 30 feet at Greenwood, on Hardscrabble Creek, and near Chandler, south of Canyon. Near La Junta it is three feet thick. . . . Usually it is soft, somewhat mixed with sandy shale, and of yellowish color. The fossil known as Pugnellus occurs abundantly in the formation in the southwestern portion of the area.” Writing of this same Upper Carlile member as it occurs in the Apishapa Quadrangle some 30 miles west of La Junta, Stose* describes it as fol- lows: “In most places yellow sandstone 10 to 20 feet thick occurs at the top. The sandstone is calcareous in fresh exposure and is generally very fossiliferous in the upper part, its fragments being marked by casts of a large, strongly ribbed coiled ammonite, Prionocyclus wyomingensis.” This upper sandstone member thins out on approaching La Junta and becomes three feet thick or less. At the same time it loses its sandy character and becomes a crystalline limestone of grayish color that weathers to a dark rusty brown. It is also very fossiliferous, containing the same fossils mentioned above by Darton and Stose and including abundant Ostrea and occasionally sharks’ teeth. Stose mentions the fact that the sandstone in the Apishapa Quadrangle in fresh exposure is calcareous. In the La Junta area it becomes altogether a limestone that is invariably crystalline. A typicai sampie of this rock dissolved in hydrochloric acid gave less than 1 per cent insoluble matter. This upper limestone member is, in most of the La Junta area, sharply defined from the overlying Timpas limestone; but northeast of La Junta a change is to be noted. The rock loses in part its crystalline appearance and its uniform brownish color and becomes mottled white and brown. The irregular brown spots appear almost like inclosed fragments in the prevailing grayish white mass; but the frayed nature of the boundary line of these brown spots shows that they are due to local oxidation of the furruginous contents or to infiltration. At the same time the stratum loses its sharply defined upper edge and it becomes impossible to draw the line between this supposed Carlile member and the overlying white, chalky Timpas limestone. The two are apparently one. 2N. H. Darton: U. S. Geol. Survey, Professional Paper No. 52, 1906, p. 28. 3 George W. Stose: Folio, U. S. Geol. Survey No. 186, 1912, p. 6. XXXITI—BwvuLut. Grou. Soc. AM., Vou. 34, 1922 498 H. B. PATTON—CARLILE SHALE AND TIMPAS LIMESTONE The above described characteristics are well shown at the base of the cliff on the south side of Horse Creek, in the northeast quarter of section 30, township 22 south, range 53 west, and they continue for 5 or 6 miles northeast of this point, which is as far as the field-work was carried. FIGURE 2.—Contact of Timpas Limestone and Carlile Shale The contact occurs in Anderson Arroyo, about 7 miles south of La Junta. The pho- tograph shows the soft black shale at bottom, the 3-foot brown limestone that marks the top of the Carlile shale in the middle, and the white, basal Timpas limestone at the top. CARLILE FossIL IN THE Timpas LIMESTONE In line with the observed merging of these two limestone members at the top of the Carlile and the bottom of the Timpas is the discovery of a recognized characteristic Benton fossil in the basal limestone of the Timpas. Near the center of the east half of section 27, township 22 south, range 53 west, and about 3 miles east of the location above given, a specimen of Inoceramus was collected near the base of the Timpas limestone. This fossil has been identified by Prof. Junius Henderson, of the University of Colorado, as Inoceramus labiatus, a form considered characteristic of the Benton group and very common in the Greenhorn limestone member of that group. We have here, then, a case of a sandstone member thinning out toward the east and passing into a crystalline limestone, and the eventual merg- ing of that limestone into the basal limestone member of a higher group. We also have, associated therewith, the passing of a typical fossil of the lower group up into the higher group. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 499-506 SEPTEMBER 30, 1923 GLACIAL LAKE PROBLEMS +* BY GEORGE H. CHADWICK (Presented before the Society December 30, 1922) CONTENTS Page Den auHe Ad PAkeC. VY AMURCI 6. so. oo cls ce cc avc cc tieccrecerdesceecens 499 TIER TET OUTNENOES is 5 la 0 5. dina ooo blo myn'b inte wie wip oie. oni ols e 6w'de. te tenneee 501 iter Le AIMATCTOQIN, 90 3 ooo ooo ce cecne du ss cvaadsaecceveceas 501 a Rene | VTi RRO Cid onc conde sear erdcaredacnecsesces Oe EOL BALE WOWRCIIY.s oo. ccc occ reccdcccascssccsccess OZ Ea Re Ao. aia, aie d,s 0's ose S!se vid st ainele O06 Gre dccisewe 503 I EES ELI 1S Oi ort tata. die n1SIG ofa sin a Ao Bp Bie Oeic wlelAa en oe eels belo é.e 503 EST UN PC Uh 01 1 rr a 503 The Algonquin lakes......... ere > ae a ee aa E ee Sada in ee aja pen wee 504 Peeererttion CRATE..26....-000- ee Nas are aieNes oid Welecia eo aD Se ere eee 5O5 ea Ee 2 SOE VAS peat Se ely ie eis Ad fp) s 5 RY 8 505 ae PER OUR CL Gls debut cpo ous olcsccscccscenesavacedecods 505 LAKE WAYNE AND LAKE VANUXEM Year by year the story of the Laurentian glacial lakes grows more complicated. The steadily falling waters of our youthful innocence are being replaced by a pulsating rise and fall due to rhythmic oscillations of the ice-front. One of these pulsations was long ago recognized by Fairchild? in his “free drainage” stage of lowered escape followed by the restoration of “Lake Vanuxem.” Fairchild has frequently predicted that the real history would prove to be more complex than existing knowledge revealed. Leverett and Taylor’s recent exposition® of the caprices of the ice on the thumb of Michigan instantly involves western and central New York, for the moment the water levels fell below the Grand River outlet they must go out by the Mohawk. The control channels of “Lake Wayne” must be sought at either Batavia or Syracuse. Herein is introduced a new element in the recognized New York lake 1 Manuscript received by the Secretary of the Society May 1, 1923. ? Bull. 118, N. Y. State Museum, p. 80; Bull. 127, N. Y. State Museum, pp. 50-59. #Mon. LIII, U. 8. Geol. Survey, pp. 364-370. (499 ) 500 G. H. CHADWICK—GLACIAL LAKE PROBLEMS succession. Hitherto it had been believed that the first of the Erie Basin waters to gain admission into central New York (the Genesee and Finger Lake valleys) was Lake Warren. In Fairchild’s conception “Lake Vanuxem” stood as the earliest water body with easterly (Mohawk) es- cape, but he ascribed to Vanuxem no drainage from west of Batavia. Yet, if we correctly understand the relations, the episode of Lake Vanuxem and the “free drainage” interim is the only known place in the New York succession into which “Lake Wayne” can be fitted. The admission of the Warren waters into central New York, past the Batavia salient, without conspicuous channeling on that salient presented a real problem to Fairchild.* Practical coincidence of the merging water levels had to be subsumed. But if the Erie waters already flowed east- ward, the restored Warren level would reach to Syracuse from its initia- tion and this particular puzzle be eliminated. Rather, the problem is pushed back to Lake Wayne, leaving the apparent absence of channels north of Batavia still a matter of inquiry. Possibly the control point is actually somewhat farther east, near Le Roy, where there are heavy channels just below the Warren beaches. None of the Le Roy channels appears, however, to fulfill the require- ments for the long-lved Wayne spillway. They conform to the tem- porary paths of waters rushing to a new confluence, not to a stabilized outlet. For that we must turn to Syracuse. Here we find at once a splendid channel at the right altitude (about 40 feet below Warren) hitherto unreferred to any fixed water plane. This is the “Gulf” west of Marcellus.* It is confidently beleved that the “Gulf” channel carried the Wayne waters prior to Lake Warren, and that it did not function again subsequent to the Warren flooding. A curious fact concerning the “Gulf” remains, nevertheless. Below its intake it is distinctly depicted by Fairchild as a “two-story” channel (the only one he so represents), with the lower story much narrower than the upper, thus indicating diminished water flow. If this narrower inner channel were cut during the ice readvance following the “free drainage” stage, as seems likely, then the restored level (‘second Vanuxem”) would appear to have been robbed of the Erie drainage by readvance also at Batavia (or Le Roy?). This would mean that while “first?” Vanuxem included the Erie flow from Wayne downward to its minimum stand and extinction in “free drainage,” or even through the earlier rising levels of its restoration, there was no “restored Lake Wayne.” but only local waters of the restored (incorrectly “second”) Lake Vanuxem coursing * Bull. 127, N. Y. State Museum, pp. 51-52. ° Bull. 127, N. Y. State Museum, pp. 26-30, pls. 4, 18, 19A. ¢ LAKE WAYNE AND LAKE VANUXEM 501 through the “Gulf,” while the Erie Basin waters were obstructed at Batavia and thrown back on the Grand River outlet as Lake Warren. This ice advance would obliterate the earlier channels at Batavia, but there is still the old difficulty of getting the Warren level eastward again past this point without a trace. Lake Lunpy (?) OUTLET With the Wayne outlet at Marcellus (Syracuse), the fate of the Erie Basin waters during the “free drainage” interval remains to be consid- ered. Following westward (upstream) the capacious channels of this stage, and noting their extensive delta deposits where they cross the Genesee and similar valleys, one is impressed with the belief that they carried more than local flow. At their upper end, north of Le Roy, the channel is a splendid rock-cut, over a mile long, a hundred feet deep, and a quarter mile wide. Its col appears to have been originally some 20 feet or more under the plane of the neighboring Dana beaches, but to have been somewhat silted up during the Dana stage. Back of this broad intake at Fort Hill, with present altitude about 680 feet, must have lain a huge lake, stretching to Detroit, hitherto unrecognized as such. Its close correspondence in level suggests that its beaches in the Erie Basin have been confused with those of the long subsequent Lake Dana. Spencer in 1894 described the Lundy beach and once incidentally used the expression “the Lundy lake,” a name which thus seems to have no standing as against the properly proposed and worthy name of Lake Dana, subsequently given by Fairchild to his Geneva beach.* But should it appear on further study that the Lundy beach correlates with the Fort Hill channel, as is very possible, then both names will stand. Indeed, the Belcoda and other channels on the same meridian may eventually explain other features in the complex of beaches at this general horizon in the Erie Basin. RESTORATION OF LAKE AMSTERDAM During the “free drainage” stage the Mohawk Valley was necessarily unblocked at the east, giving passage to Fairchild’s “glacio-Mohawk River.” But Fairchild has shown’ that the east-leading channels of sub- sequent date from lowering Warren and Dana terminate east of Syracuse ® See map, Bull. 127, N. Y. State Museum, pl. 2. * Amer. Jour. Sci., vol. 47, pp. 207-212. Said to be 25 to 40 feet out of harmony with Lake Dana, in U. S. Geol. Survey Mon. 42, p. 772. 8 Amer. Jour. Sci., vol. 7, 1899, pp. 260-1; Bull. Geol. Soc. Amer., vol. 10, pp. 56-57. ® Amer. Jour. Sci., vol. 7, 1899, p. 262; compare also 20th Ann. Rept. N. Y. State Geologist, pp. 112 ef sea., pl. 16; Bull. 160. N. Y. State Museum. p. 32. 502 G. H. CHADWICK—GLACIAL LAKE PROBLEMS _ (at Mycenae) considerably above the level of the Rome outlet, or higher than the free drainage channels. The inevitable conclusion is that they discharged into a restored Lake Amsterdam, due to reblocking of the Mohawk at its lower end (Schenectady). It is reasonable that any re- advance of the ice at Syracuse sufficient to restore the Grand River outlet must have been accompanied (or slightly preceded) by a powerful thrust in the Hudson Valley, of which we here have the confirmation. Appar- ently this forward shove was felt also (a bit later?) at Batavia, thus sundering Warren and Vanuxem as above intimated. EASTWARD REACH OF LAKE ARKONA More puzzling questions revolve around earlier reexpansions of the ice. Taylor thinks that Lake Arkona invaded central New York before the readvance extinguished it. The position of the overriding Alden moraine in the wider portion of the Genesee Valley (where the Warren beach is strong but single), and thence eastward to the Seneca Valley, is well above the Warren level and shows that the ice must have there destroyed any Arkona beaches, except far south up the valleys, where they would necessarily be weak. Careful search may yet reveal these; probable beaches and notches occur, 20 feet above the Warren shore, at and east of Geneseo, but the best record is found in the large 850-foot delta terrace at the mouth of the Mount Morris canyon, which could not have been built in Warren waters, because the canyon had been cut far back and deepened in the stage of lowered escape preceding Warren. The fact that the moraine of readvance barely sunders the Mount Morris and New- © berry levels at the critical points near Hast Bloomfield, Reeds Corners, and Gorham is evidence that even Newberry had been swallowed down into Arkona before that readvance occurred. (See the chart, page 506.) WESTWARD REACH oF LAKE NEWBERRY In his later writings and maps*® Fairchild carries Lake Newberry into the Genesee Valley from the east at this same moment in the history preceding Lake Hall. While the overriding ice has destroyed the records, making it impossible to say that Newberry did not have such an exten- sion prior to Arkona, yet it seems to the writer unlikely that the New- berry level entered the Canandaigua Valley before its restoration, and not immediately even then, being momentarily excluded by a restoration of the Potter Lake with new outlet east of Gorham. This presently fell to Newberry, and when the latter almost immediately coalesced with the 10 Bull. 106, N. Y. State Museum, p. 32; Bull. 127, N. Y. State Museum, pl. 35; etc. WESTWARD REACH OF LAKE NEWBERRY 503 Genesee waters these were at the Pearl Creek outlet, so exactly coincident in elevation that a divided escape ensued until the unblocking of the Linwood channel established Lake Hall.*+ It should be noted that Hall thus becomes a fairly fixed water body, not a series of lowering stages, _ though it may have been let down once, some 20 feet, to the Stafford channels. A NEW GENESEE LAKE Studies now proceeding on the complicated history of the Genesee Valley lakes indicate that Lake Dansville was admitted into the Canan- daigua Valley by way of the Hunt Hollow strait following Lake Naples, and was then lowered down on this pass, instituting a new member in the Genesee succession, here named the “Livonia Lake.” By opening of the Bethany channels Livonia became the Mount Morris falling waters, whose intricate history involved one more brief escape to the Canan- daigua Valley by the Cheshire channels, as well as temporary separation from the Wyoming Valley by lowering on the Pearl Creek outlet channel. Hupson VALLEY LAKES Greater interest attaches to the behavior of the Hudson-Champlain Valley during ice-waning. Woodworth’s interpretation’? of this behavior involved a peripheral bulge and a wave of uplift. Fairchild, whose early conception of the uplift as a rigid tilting was opposed to Woodworth’s, has found independent evidence of the peripheral bulge in his work on the Susquehanna River.** Antevs, Daly, and others assert the existence of the bulge and of lakes restrained behind it. Of these lakes one must have occupied New York Harbor and its environs, perhaps continuous with that in Long Island Sound; for this the name “Lake Manhattan” is here suggested. As the ice waned and the pursuing bulge raised Man- hattan, the Tappan Zee would have held a water body which we may call “Lake Haverstraw.” Perhaps even a third stage, north of the High- lands, preceded the inception of Lake Albany, and this might suitably be called “Lake Newburgh.” The writer finds it difficult to conceive that any of these waters were salt, or with marine organisms. LAKE VERMONT AND LAKE Emmons It becomes necessary at this point to reinstate Woodworth’s Lake Ver- mont, for, like the preceding, this was sundered from the tides by the 11 Bull. 106, N. Y. State Museum, p. 33, pl. 6. 2 Bull. 84. N. Y. State Museum, pp. 229, 232. 18 Science, n. s., vol. 57, no. 1465, p. 113. 504 G. H. CHADWICK——GLACIAL LAKE PROBLEMS migrating bulge. That it had no free communication with salt water: via the Hudson Valley is an inevitable corollary of Fairchild’s discussion of the Round Lake region.1* Analysis of that paper shows that long before the unblocking of the north end of the Adirondacks, while still Lake Iroquois was discharging through the Mohawk and cutting the Round Lake channel, the Hudson Valley at that point had lifted so far as to confine the Hudson River to the narrow trench it was reexcavating in the clays of the Lake Albany filling. Lake Albany was gone. There was no open strait of salt water (or any other water) from New York to Plattsburg, but a river of fresh water flowing (with a gradient) south- ward and holding Lake Vermont to superoceanic level. The true marine waters (Hochelagan Sea) entered the Champlain Valley only when ad- mitted from the northeast, past Quebec. By the original definition “Gilbert Gulf” is the portion of these marie (tidelevel) waters confined to the Ontario Basin, and the name should not be extended over the region in which Woodworth’s “Hochelagan Sea” has clear priority.” The Vermont beaches are finely developed at 740 feet above tide and down, both around Covey Hill and far into the Ontario-Saint Lawrence Valley. The true marine beaches are those originally recognized as such from 523 feet above tide down, on Covey Hill. Between these two sets is a gap of nearly 100 feet, marking the elevation of Vermont waters above sealevel just prior to their extinction. Above the Vermont beaches, between them and Iroquois, in the Ontario-Saint Lawrence Valley, lie the “Emmons” beaches of Fairchild, rediscovered and renamed “Frontenac” by Taylor.*® THE ALGONQUIN LAKES However intricately interwoven may be the Algonquin beaches, in point of historical sequence there are several distinct water bodies at present passing under the name “Lake Algonquin.” Leverett and Taylor discriminate (1) an “early Lake Algonquin” confined to the south end of the Huron basin, with Detroit (that is, Port Huron) outlet; (2) doubtfully a tripartite lake with outflow divided past Detroit and Chi- cago, which seems to be an expanded Lake Chicago; (3) the true Algon- quin, tripartite, with Trent River escape, and (4) the second Algonquin, restored to Port Huron outlet. To avoid confusion of speech, it is sug- gested that the first stage be called rather the primitive Huron, and that 14 Bull. 195, N. Y. State Museum, pp. 12-15, and map pl.; compare also Bull. 215-6, N. Y. State Museum, pp. 28, 46, figs. 10, 11; Bull. 154, N. Y. State Museum, pp. 30-3, fig. 5; Bull. Geol. Soc. Amer., vol. 33, p. 525. 16 Bull. 84, N. Y. State Museum, p. 220. 16 Bull. 158, N. Y. State Museum, p. 34; Bull. 164, N. Y. State Museum, p. 22; Mon. LIII, U. S. Geol. Survey, pp. 325, 445; Proc. Roch. Acad. Sci., vol. 5, p. 138. THE ALGONQUIN LAKES 505 the almost resundered Huron waters during the later Nipissing-Ottawa outlet stage be named “Huronipissing.” The temporary lifting of Port Huron to level with or above the Chicago outlet and subsequent abate- ment witnesses to the migrating bulge hereinbefore advocated. CORRELATION CHART The relations of these water bodies as above understood are exhibited in the accompanying correlation chart, in which contemporaneity is hori- zontally represented and time reads from top downward. Proportional time values are not closely attempted with present inadequate knowledge, but attention is called to the rhythmically spaced ice maxima, which may have a coefficient of approximately 26,000 years. The purpose of the chart is to focus attention on outstanding problems and provoke fresh attack. A similar chart projected for the minor lakes of western and central New York is deferred to a future writing, but the following pertinent note is retained here: CATTARAUGUS LAKES Exploration in the Cattaraugus country during the past summer re- vealed a fine channel leading from the South Branch Cattaraugus Creek westward toward New Albion, with summit elevation about 1,430 feet above tide. As this is intermediate in altitude between the Lime Lake (Machias) and Persia outlets already recognized by Fairchild,’ the suc- cession of lakes in the Cattaraugus Valley gains a new member. Another probable outlet examined is the pass north of Ellicottville at about 1,640 feet aneroid (sheet not issued). It would seem that the Dayton pass used by the Buffalo and Jamestown division of the Erie Railway must also have carried some overflow for a time, but there is no good channel across the col. ana SOME PREGLACIAL RIVERS In the nature of a supplementary proposal, the following names are tentatively put forward for certain fairly established rivers of preglacial drainage: “Allegowanda” for the ancient upper Allegany, with discharge by Gowanda to the lower Cattaraugus Valley; “Geneseraga” for the ancient Genesee past Sonyea into the Canaseraga trunk valley and, thence lower, through the Irondequoit trough, and “Senecahanna” for the ancient upper Susquehanna flowing out by the Seneca Lake Valley to the Ontarian River. ° 17 Bull. 106, N. Y. State Museum, pp. 16-17, 35. G. H. CHADWICK—-GLACIAL LAKE PROBLEMS 506 Oumun a, 99T GuLinp saynT yoarp uniyuaimoy ay, fo wo1njorg—T[ aunpiy UmMoy S Ajaso? fOl SOV4DU ously FUOAL--BD" JO SPILIVDAPBOIAS [PSIDUI4Y 5 svonbo4y HIffO 470 sdo4p UusInjor YMOYOpY Uvwo\y ul SABA "SO" P4 / ui sayo7] viunsoar Suisse) fou MOfy fF MOlZ 40 “OMIA > 2$0u/1p 4p WAaississlyyy fo sasopuriog] ro PaSSO4? fous SUOISIAITT - abnulpsp Ag PISsOs? 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MHASH AAN “ws Sayos fRr0/ = —ubgyoyuoy © 8erses payorjdiwo> 207 4 P8429 wy NIVIAWVHD |FINTAMVILG| AFTTITYA | Pbnhoa|b22Vag| DyNay prhopunia, AZTTIVA WYOK MAN -NOSCA}/| ONY HWOV7IG| YM YHOWw SIUVY7T YIONISY JISINIO| NYFLSIM (Sees aly (ea ms (24? oes) Apjusy 221L0M0G ¥7 ly a4 OS UDY BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 507-524 SEPTEMBER 30, 1923 ORDOVICIAN OVERLAP IN THE PIEDMONT PROVINCE OF PENNSYLVANIA AND MARYLAND? BY GEORGE W. STOSE AND ANNA I. JONAS (Presented before the Society December 29, 1922) CONTENTS Page SAETDERR UTES Gh SR tg As Sie eS Serge es i Oe a eee 507 Terao des CONCSLOSA OVETIAD «oi. c 5c PRY. sei Y —FIe y. Was RW Wo SR ca a oe OY - ISS WQS QINRR Oi a8 FN ‘ es PS SYSZN! > S oN i g a SSRN 1 A awa LL See ID En as Wh EE Daly \A~e@|4aao Shonen hae ca oo NO Saat =4E ey INOLSIW/IT Rie TOT eet ai na ae aa a VIOLSINOD pee 2 See eS — eee oD payee OIDITVIOD ‘OSB OMS dq} JO ATO} VUITXOIdde OG 0F PoOAST[OG 918 PUe YSTTOS suodeyT oO} 0} UMOP OUTPOTUV VSpPIY OUT 94} JO SyuRy oy} WO SUOTIVUIIOS LOpTO [[V ARLAOAO YOY “SMOT)VULIOF VSO}SOUO,) PUR ODITRIO;) oY} JO SOUOJSOUT] SHOVDR][ISIw ATVYS PUB So[eVyS pozrsodep ‘owl, (AzeyD Alqeqoid) UvIdIAOPAG UL 19}Vl “Vos OY} JO WOISSXISSUBAJOI OTT, UDJAIVQ PUD WOUYDZLWOUWIPIY WHWIAOPAQ WOZDT—OTL WAY —=———— —————— Pree ySUvreNererrigeet es Se a ea ay MYAWy 7 IMSS S v7 N/ J ; Sty YOs =——=== a a 7 ip yea LF] INIVIHIOIQNO I= ——— FFF eee eee eee = = : SS i OM Sa 63 SS i Se ee SS SS 5Y4 gsTros—E AND JONAS—ORDOVICIAN IN PIEDMONT PROVINCE had been more or less consolidated into limestone by pressure, were eroded on the flanks of the uplift and the older and harder siliceous sedi- ments were laid bare and also partly eroded. The beveled edges of the limestone formations thus appeared one after another on the flanks of the bowed-up siliceous sediments, as shown in the diagrammatic section, figure 15. The reinvasion of the sea later in Ordovician time, probably in the Chazy epoch, spread a mantle of sediment unconformably over the beveled edges of the older formations, as shown in figure 16. Fragments of limestone from the waste of the eroded underlying or adjacent forma- tions were included in the initial sediments, giving rise to thick lime- stone conglomerates. Fine black argillaceous silt that was carried into this sea was apparently not washed from the Piedmont land area to the southeast, but was probably brought from some more distant source at the head of the bay to the northeast. This argillaceous silt formed the Cocalico shale in the open part of the basin, where currents supplied it freely, and at approximately the same time it probably contributed the argillaceous matter to the impure slaty Conestoga limestone on the south- east side of the basin, where the water was shallower owing to the Mine Ridge uplift, and the currents were thus deflected or retarded, so that a larger proportion of lime silt was there deposited. Later, the further upbowing of the Mine Ridge anticline and of minor anticlines on its flanks, accompanied by thrust-faulting, resulted in the emergence of the land above the sea and the erosion of the folded strata, as shown’, in figure 17, which presents conditions as they are today. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34. PP. 525-540 SEPTEMBER 30, 1923 APPALACHIAN BAUXITE DEPOSITS? BY WILBUR A. NELSON (Read before the Society December 30, 1922) CONTENTS Page woo Sis THOSVE ISI 2 eek Is i SR Bir cena eine he AE Ne ne aan ee oe ae 525 (PUL WES DESEREMIO I y 6) te EAR STI er rk a Aen Pee a a 526 ee Na EPI RE ei otine ay cia orate es atans, & A 6 Suaveheneinne «bie ise Sse wists Vere ele 'e ela 6 6 528 > TEAS BEE BA 2 Ss Bye ae a nea Pega Myke yah eg Bhan Soa 'e 529 Neue UMMEER RE MEMTTOP AML) AEINATIEC cos tevereccs climate ic eel Sie bk ats Cate le oe Siete tbe wa’ ce sla Giese 530 HES aren tote en RIS 5 cel Witte beh ate 76 a> arrallsl aisiccese/miisuw Sich anes aoalhe.ateca piste wa a 5382 ME MOE ON V OO MCT UAVCTUGS sco sve, 005.505. w.b.6) tie, boil wetdl'en’ sie Gin, Klae wits. 010% et rath orate os 536 mee A MMCe TANCE] OMIM Sener. aye. ced abe hans ae ascetics valle: clini a o! braiicy-e, S, accal bse, wha sislieewlia’'s Gow Sixes 539 ia ns coe TPMT Tree ey ae is Cin eo ee aa ala, ote Gig 6a wile Ghe,e 6 Se ie Ne daw ors gore ee 539 INTRODUCTION In a paper given at the 1921 annual meeting of the Geological Society of America, entitled “A volcanic ash-bed in the Ordovician of Tennessee, Kentucky, and Alabama,” the following statement was made in regard to a new theory of the formation of bauxite deposits: “Experiments made on bentonite show that when boiled with five times normal solution of sulphuric acid for five hours the colloidal properties are destroyed; that about 85 per cent of the aluminum oxide goes into solution as aluminum sulphate, along with the alkalies present, but that all the silica except a trace remained undissolved. This fact offers a possible solution to the origin of bauxite, as laboratory experiments show that such a solution of aluminum sulphate is precipitated by a solution of tannic acid after standing for a few days. Deposits of bentonite occurring in contact with pyritiferous rocks would readily have part of their aluminum contents dissolved out by the sulphuric acid in the ground-water, and such a solution of aluminum sulphate, it seems, would be precipitated by natural reducing agents, such as tannic acid or acid peat-forming bacteria, and thus form certain of our present bauxite deposits.” Following these experiments, it was decided to visit the Chattanooga bauxite deposits and make a detailed study of the geology of the Mission- 1 Manuscript received by the Secretary of the Society January 29, 1923. (525) 526 Ww. A. NELSON—-APPALACHIAN BAUXITE DEPOSITS ary Ridge section, lying just east of the city, to see if the bed of altered voleanic ash, the bentonite, which should occur in the Ordovician rocks on the west side of Missionary Ridge, was present. The area in East Chattanooga lying at the west foot of the ridge and directly to the west of the large bauxite mines of the Kalbfleisch Chem- ical Corporation was visited and a fine exposure of the bentonite found at the top of Bragg’s quarry, located at the intersection of Bragg Street with the Southern Railway, and later a good exposure was found in the yard of the Avondale school, about five-twelfths of a mile farther south. Two-thirds of a mile east of these outcrops occur the bauxite mines of Missionary Ridge. PHYSIOGRAPHY In the Chattanooga area there are a number of well defined peneplains, and it is thought that one of these played an important part in the for- mation of the bauxite. They present a most striking aspect when viewed from Lookout Mountain, the top of which is the highest of these old plains. It was called the Cumberland tableland by Safford.? This pene- plain has been considered as of Carboniferous age by Hayes.* Going to the east, we find as the next lowest level the top of White Oak Mountain, with an elevation of from 1,300 to 1,500 feet. From White Oak Mountain on the east, to Waldens Ridge on the west, is a distance from 12 to 18 miles, and in this intervening area are located a number of low- lying ridges of different elevations and the main valley of the Tennessee River. A study of the region shows that Missionary Ridge, with an elevation of 1,000 feet above sealevel, may represent the remnant of another peneplain, and that a series of parallel ridges whose crests are all of approximately the same elevation (850 feet), and which lie between Missionary Ridge and the White Oak Mountain, is the most recent pene- plain of this section, with the exception of the present plain of the Tennessee River, with an elevation at Chattanooga of 670 feet. It is the old peneplain, now lying at an elevation of approximately 850 feet, which particularly interests us in our study of the origin of the bauxite deposits, for the bauxite occurring on the east side of Missionary Ridge is found at this elevation. At that geologic time the present topog- raphy would indicate there existed between Missionary Ridge, on the west, and White Oak Mountain, on the east, a broad, flat, featureless plain, 8 to-10 miles wide, with swamps occurring along the eastern base of what is now Missionary Ridge. Bordering the banks of a mighty river then 2 J. M. Safford: Geology of Tennessee, 1869, p. 10. °C. W. Hayes: Sixteenth Annual Report, U. S. Geol. Survey, part iii, 1895, p. 592. PHYSIOGRAPHY 527 meandering in its sluggish course across this ancient land (the fore- runner of the present Tennessee) were large marshy, swamp areas coy- ered with dense plant growth. In this area, along the eastern base of this ridge, occurred many springs, bringing up large quantities of water charged with mineral salts, which quickly precipitated on coming in contact with the acid swamp waters and bacterial life of this old geologic plain. Watson‘ states that “the formation of this plain was probably during Eocene time. . . . In this event they [the bauxite deposits] must have been formed near the close of the period of the Eocene baseleveling.” The peneplain of which the top of White Oak Mountain is a remnant is capped by Mississippian rock and very probably is an isolated eastern remnant of the Highland Rim peneplain of Middle Tennessee, which on the western side of Middle Tennessee is covered by upper Cretaceous gravel of the Tuscaloosa formation. Along the western edge of the White Oak Mountain-Highland Rim peneplain are a number of well defined terraces along the Tennessee River. The terraces have been described by Wade,’ who distinguishes six distinct terraces below the top of the White Oak Mountain-Highland Rim peneplain, occurring at approximately 780-800 feet, 620-700 feet. 600 feet, 500 feet, 420 feet, and 380 feet, the last being about 10 feet above the floodplain of the present Tennessee River, and considers the upper two terraces, occurring at 780-800 and at 620-700 feet, to be of Phocene age, while the terraces occurring at 600 feet and lower he re- gards as of Pleistocene age. These terraces should tie into peneplains formed during those periods, and it is considered that the peneplain on which the bauxite deposits at Chattanooga were formed, and which occurs approximately 450 feet below the top of the White Oak Mountain-High- land Rim peneplain at Hast Chattanooga, corresponds in age to the river terrace occurring at 600 feet elevation, mentioned above by Wade as having been formed at the beginning of the Pleistocene period. This terrace occurs approximately 450 feet below the White Oak Mountain- Highland Rim peneplain. In this connection it is interesting to compare the table of terraces of the Pleistocene and upper Pliocene periods, prepared by Osborn and Reeds,® with the above conclusions. Their highest river terraces, stated *Thos. L. Watson: Georgia Geological Survey, Bull. 11, 1904, p. 130. > Bruce Wade: Gravels of West Tennessee Valley. Tennessee Geol. Survey. Rec. of Tennessee, vol. 7, 1917, pp. 55-90. ®°H. F. Osborn and C. A. Reeds: Old and new standards of Pleistocene division in relation to the prehistory of man in Hurope. Bull. Geol. Soe. Am., vol. 33, no. 3, 1922, fig. 13, pp. 411-490. 528 Ww. A. NELSON—-APPALACHIAN BAUXITE DEPOSITS to have been formed at the beginning of the Pleistocene period, are shown to occur at 90 to 100 meters above existing beds of large rivers, which checks in roughly with the 600-foot Tennessee River terrace discussed above, as it occurs approximately 260 feet above the Tennessee River. Osborn and Reeds consider this to have been the period of Nebraskan glaciation. | It is considered that the bauxite deposits of the Chattanooga district were formed at a much later date than the Eocene, and that one is justi- fied on the basis of the above correlation of tentatively placing their age as of early Pleistocene. Following the close of this baseleveling period came an upward warping of the earth’s crust, and this Highland Rim- White Oak Mountain peneplain was uplifted and tilted upward toward the east, so that at the foot of the Cumberland Plateau this peneplain has only an elevation of 1,000 feet as against the elevation of 1,300 feet of the White Oak Mountain, or a progressive uplift toward the east of 300 feet. This upward movement, which probably started gradually during the Phocene or at the beginning of Pleistocene time, with a tilt- ing upward of the rocks to the east, naturally caused a migration of the streams flowing on this old peneplain to the western side of whatever valleys they occupied, and in this particular valley between Missionary Ridge and White Oak Mountain caused a shifting of the stream up close to the eastern base of Missionary Ridge and the location of river swamp areas in this particular region. A study of the Kalbfleisch bauxite mines in this region shows lying to the west of the bauxite deposits and contiguous to it a deposit of dark brown lignite and lgnitic clay, which was measured where exposed as being 36 feet long and having a maximum thickness of 25 feet. The presence of this lignite deposit in connection with the bauxite ore shows very clearly that this ore was formed on an old peneplain which now has an approximate elevation of 850 feet, and that the bauxite was formed in an area where swamp conditions existed suitable for peat formation and deposition and where the surface waters were of the acid swamp- water type, full of tannic and humic acids. GEOLOGY Starting at Bragg’s quarry, in Hast Chattanooga, and going up the west side of Missionary Ridge, one finds an excellent section, beginning at the base of the Lowyille formation of the Black River group, of Ordo- vician age (in which the bentonite occurs), and extending up into the red shales and. limestones of the Rockwood formation, of Silurian age, GEOLOGY AND STRUCTURE 529 which are here overlain by cherty Knox dolomite thrust over the Silurian from the east and forming the cap of Missionary Ridge. STRUCTURE 2 fe) Q. OOL (or) fe) oO fa Jennessee River /42/n west i} fF Quarry 8 fe — ,006 The strata of the Chat- tanooga - Missionary Ridge area have been faulted and folded in a manner similar to that of the Appalachian re- gion, and such folding and faulting has been given the name of Ap- palachian structure. A cross-section of the geology, as it occurs on a line extending in a roughly west-east direc- tion from Bragg’s quarry, in East Chattanooga, across the crest of Mis- ‘sionary Ridge and on to- ward the White Oak Mountain, shows the Lowville formation con- taining the 40-inch layer of bentonite, dipping slightly to the southeast under Missionary Ridge. A study of this section shows that the rocks have varying dips of from 2 to 30 degrees, all to the southeast, and that the strata dip under the west side of the ridge. The strata quickly turn up- ward as they near the line of the thrust-fault and form a closely com- pressed synclinal fold overturned toward the west. aS ew iy XXXV—BULL. GEOL. Soc. AM., Vou. 34. 1922 Fast Chattanooga LSA x Bragg Limestone Quarry Southern Railway S9dIod AdVNOISSIW pry hanuoissipy ssowon woldag 0100,00aH—T WIODIST jaAa7T UlejAaauved /2/O ISeCT 530 Ww. A. NELSON——-APPALACHIAN BAUXITE DEPOSITS One of the major thrust-faults of the region, having a low angle of thrust to the northwest and having its strike in a north 30 degrees east — course along the west side of the crest of Missionary Ridge, has thrust over the closely compressed fold, of Silurian and Ordovician rocks, the cherty Knox dolomite of Canadian and Ozarkian ages. ; The bauxite deposits occur on the east side of Missionary Ridge, a short distance below the crest, at a point where the line of the thrust- fault is still very near to the surface. At this point, which was at the time of formation of the bauxite an old peneplain, the ground-water circulating upward along this fault readily came to the surface through the few feet of fractured chert and dolomite lying between the fault-plane and the ancient land surface on which these underground waters came forth. BENTONITE AND BAUXITE The bentonite layer outcropping at the top of Brageg’s quarry dips underground to the eastward and, as is shown by the accompanying cross- FicuRE 2.—Bed of Bentonite The bed outcrops at the top of the Bragg limestone quarry, East Chattanooga, Tennessee. Photograph by Wilbur A. Nelson. section, quickly turns upward and is cut off by the thrust-fault just above which is now found the bauxite deposits. The bentonite outcropping just five-eighths of a mile to the west of the Kalbfleisch bauxite mines measures 40 inches in thickness. It rests on the massive pure limestone of the Lowville formation and is overlain ANALYSIS OF BENTONITE 531 in the quarry by 2 feet of yellow, earthy, mud-cracked limestone. An analysis’ of the bentonite is as follows: Complete Analysis of Bentonite, Bragg’s Quarry, East Chattanooga Per cent Ss DSR SILER AOR ats an Spt cit ARUN aes a 51.88 HANTS Bele Ts ae SR SIR Fa ee 3 ht co Mie i oe a ao pe 1943 aruba AO, EBS ef I AO rebate arcana. =) e Sic ate. ie ere eater Sule )o es 3.08 SOAOIE SS sire wale tae sane ete eye Roe ie epee Sle Sie haber aya hota 8 ahh ackie s 4.54 jE OS A RS Bc yk SAN Arcata OD ae aI ea OO 4.86 BMF ocranes aye raisesre aus en atest an ee Sa on eA lalne ba wets be we 1.56 Me eR Octo he co hers a ede se tinea Y ada de Ri R OPE RUDD ar aS Ciel oie i's. Si'n alu'’e a 1.94 RUN A ba ot tact Nena val ahs (Sn rts Shn Siae tw con ot nae Akane oy tags Se ere ower oe ‘ec Rs .48 MSE Seen te ica, he ER see ened oetawa eb vield scsid'sialwlsie aie as .005 conc nats PM Le oes whe ce eee Shea ns Seale oe nll ae aoe 2.94 H.O expelled at 100-110 degrees centigrade.......... 3.56 H,O expelled at 150-160 degrees centigrade.......... ro H.,O expelled at 200-210 degrees centigrade.......... .30 Hipvexpeieds ate ted Meat. io .5.2 was aie ke tio «viele Sosa o's 8 a 5.24 \ ert ohne Pe © Cee aan _ a2» qa kaolin C2 pies a es 54// Y) Uf ae Yj, Uli. White Bauxite LEE Bauxite Si Bottom of Pit FIGURE 3.—Diagrammatic Sketch of west Side of Isabella Stewart Bauxite Mine A detailed description of the Isabella Stewart mine of the Kalbfleisch Chemical Corporation, lying five-eighths of a mile west of the bentonite ‘All analyses on this and succeeding pages were made by D, F. Farrar, chemist, Tennessee Geological Survey. rt ceca} reed eT OE ERP ALR > : = = - = oS = 3 . zy I ottom of the pit is In massive fine-gramed bauxite, and the walls for 10 feet up are of this same high grade 60 per cent baunitte. Above to Missionary Ridge). id on the south corner ic kaolin: but between t. hes ot black > 7 he henite and hgnttie —_ ~~ S . , ~~) STS The Zz we = —o eat Gt iste : oe £4 =or mada oat the hanviie — == | pa q ne ft Pre made i the DaUXIie. Kaolin. Lente ang ANALYSES ANALYSES OF BAUXITE Hard Ore, National Method Per cent CIPS SS ESS ee 2 ea et pe eg ee a 9.17 Pee Shor A. Sis ee a ee oe Snes B's 's Sniwio. ose eo oo 59.47 eee aa. creas IN (rate Pe a he ere eas wie Swe Swe 1.05 SUR ht Sree 2 oie SOE as Werte Die ae ere WR oa nip ooo wk bee ees .68 Complete Analysis Per cent SOS ne ne ele ee et ee eee 5.98 PE Ne ers? Sa fers On dct SER aso wid a ee eS ee ee 60.08 MUP nA ah eRe hs Sata 2A eho chat here ata wa, cl aTaiatadn e's “ost 1 Ra Re Sonate te Pre tee te COSA Poca olds Pla eee 3.02 Penta ee Faas ea eee eee Mare ood OPS So ee es Us 29.80 Soft Ore, National Method Per cent Senet Pe es Cee CS Os ee cette ake isc aes eo 5.49 ce PTT Se ad 8 Eg i ae et hie ee ee ee 60 . 00 EN CM one Set lene ONS 3G ore Bik Goats elena limnvem 1.04 i MMM IONE, “0, UD os os eos ae eee se aoe ewe ss are ape ee as ee gt ee oe SE OS ie cece tk amet 32.68 Complete Analysis Per cent PILE TE STE gale eek ee Lae i ag ed ee in ene ar 2.40 wa ETE SG) TN are ee oe ee ey ee ee eee 60.46 CUTE ESTEE fr 1S) RS ie ee Pa ei ee a it 42 cern IONIOe, (PIO). soe cs okie Cee > cee oh eos 3.52 Ne ee nt ee ene eer Se ete en kam dnt a Sune Soc ANALYSIS OF KAOLIN National Method Per cent MRR ES ee ynr sd er Sis nt Ae ea eR eye oe aioe eee a kis 8 51.14 ne te ser Pe NS TERY tage: ke ee eke 34.68 LEE De See re EO EES St pai ce iad cir age gh 12 MN ered ee rg tee aap ne Sern Bod SSR aes vce eee ve 32 ON te Set ere ees ai ae wha aie cama cwen, oc '@ ale 14 rete hfe Rin eer tote ein Ce ay ei is Chg cc wks oso « trace ca ak 100 derrees ceniisrade .22.20235652.-.2i....01.- .48 or EVETSE iy 22 Se ton 10.84 533 534 Ww. A. NELSON—APPALACHIAN BAUXITE DEPOSITS Complete Analysis Per cent SiOG v4« vcve ahreetle as ain eee es peers woth Ratt te ee Conc 44.76 PV ers at cept ae any wate fy even eda oie, Bea lactase Ss a A ee 42.38 by 2 © Miers rig een eh A Pe yn Me Panay er a Se eh This exposure, which hes about 20 miles northwest of Manhattan, is an outcrop of a dark green rock, an igneous breccia, forming a low, domelike, grass- covered mound with a maximum elevation of about 30 feet. The total area of the mound is not more than one acre, and the weathered frag- ‘ments of the dark green rock were not found more than 100 feet beyond the limits of the symmetrical mound. The conclusion is reached that the mass is a rather small volcanic neck or pipe, of post-Permian age. Mr. Howard Tomlinson, who studied the rock in this section, pronounces it kimberlite or porphyritic peridotite. LAMAR, COLORADO In southern Prowers County, southeastern Colorado, there is an ex- posure of igneous rock which Prof. R. D. George, in a personal com- munication dated November 8, 1922, describes as follows’: “South of Lamar there is a laccolithic area in the southeastern part of township 27 south, range 46 west. The main part of the igneous area is in section 35, but extends over into section 36, and, according to a new survey made, may extend into sections 1 and 2 of township 28 south, range 46 west. The rocks of the main laccolithic bodies are very basic syenitic types. Associated with the laccoliths are 50 or more dikes of various lengths aia touching the adjacent corners of the four townships. On one of these areas is a body of porphyritic granite . . . 100 yards long and 15 to 20 yards 550 Cc. N. GOULD—CRYSTALLINE ROCKS OF THE PLAINS wide. Gilbert, in Journal of Geology, volume IV, page 821, says: ‘Fragments of various rocks are included in the laccoliths and dikes, and are of interest as revealing the nature of the lower lying terranes through which the ascend- ing liquid passed. Besides sandstones and shales similar to those constituting the wall rocks, the most abundant as well as the most notable rock is a porphyritic granite with conspicuous crystals of gray feldspar.’ This suggests his belief that the granite is an inclusion in or mass floated up by the basic igneous rocks forming the laccolith. There are at least three granite lacco- liths, but I am not entirely certain that the two smaller granite masses are in place. While I have made no petrological examination of the granite, its general appearance suggests quartz monzonite rather than a true granite.” SUBSURFACE CRYSTALLINE Rocks GENERAL STATEMENT It is, however, chiefly with subsurface igneous rocks that this paper is concerned. We may safely say that within the past five years our knowl- edge of the subsurface geology of the Great Plains, especially in certain parts of Oklahoma, Kansas, and Texas, has increased several hundred per cent. This condition has been largely brought about, either directly or indirectly, by the work of the geological departments of the various oil companies. In these States the geologist is now considered as an integral part of any oil organization, and his advice is not only sought, but acted upon, by men making large investments of time and money. A number of highly trained and very efficient men, young men for the most part, in these States are now devoting the greater part of their time to subsurface work. Logs of wells are studied and compared, and in this manner many subsurface structures of which there are no surface indications sometimes have been plotted. Considerable literature is al- ready accumulating on the subject, but the most comprehensive paper on subsurface crystallines was published by Sidney Powers.'® The net result of the work of the various geologists who are now work- ing on subsurface problems has been to throw a vast amount of new light on the underground stratigraphy and structure of the region. Unfortu- nately, much of the material collected is not yet available to the public, largely for the reason that relatively few of the oil companies have yet reached the stage where they can afford to be philanthropists; also, many of the managers of these companies. being anything but scientific men, have not yet been brought to appreciate the true worth of broadly dis- seminated scientific investigation. There is still much needless and ex- pensive duplication of work and much attempt to conceal data which would be of the greatest value in the solving of vital problems. Never- theless, each year more and more new facts are coming to light and the SUBSURFACE CRYSTALLINES 551 members of the geological fraternity are gradually accumulating a vast amount of useful information. Ten years ago relatively little was known regarding the subsurface formations of the Great Plains. Academically, the geologist knew, of course, that granite or other crystalline rocks underlaid all this region, but little was known as to the character and thickness of the sedimen- taries. Occasionally a driller reported granite in a deep well, but at that time neither the oil man nor the geologist paid much attention to his statements. NEMAHA MOUNTAINS ‘During the years 1914-1915 several wells located on well-defined anti- clines in northern Kansas began to encounter crystalline rocks, and since that time something like 30 wells have been drilled to granite in this State. The results have shown a very peculiar geological phenomenon, namely, the presence of a buried granite ridge, now known to extend from somewhere near the mouth of Platte River, in southeastern Ne- braska, entirely across the State of Kansas and into northern Oklahoma, a distance of over 200 miles. Prof. R. C. Moore, who is our best au- thority on the subject, has very fully discussed the matter in two publi- cations, one in the bulletin of the Geological Survey of Kansas’ and the other a paper read before this Society.** He has named this subsurface ridge the Nemaha Mountains. Professor Moore states that at a point near the Kansas-Nebraska line “the crystalline rocks approach to within 550 feet of the surface and attain an elevation of nearly 600 feet above sea level”? The elevation of the crest of the buried ridge gradually de- clines toward the south, granite being encountered at 3,420 feet some 25 miles north of the Oklahoma line and at 4,800 feet near Newkirk, Okla- homa. In addition to the writings by Moore, there has already grown up quite a literature on the granite ridge, particularly the writings of Haworth,’® Taylor,?° Powers,?? and Wright.?? Studies made by different geologists of the records of wells which touched crystalline rocks have shown some very interesting facts. While the data are still far from complete, enough facts are now available to postulate the presence of several granite ridges on the plains other than the Nemaha Mountains, already discussed. AMARILLO MOUNTAINS In 1905 the writer discovered along the Canadian River, in the north- ern part of the Panhandle of Texas, a series of large structures. These were duly embalmed in the literature and straightway forgotten.?* In Soe .C. N. GOULD—CRYSTALLINE ROCKS OF THE PLAINS 1917, happening to mention the fact to some business men of Amarillo, their interest was aroused, with the result that the region was revisited and a careful survey made of the largest of these structures, the John Ray Dome, in Potter and Moore counties, some 20 to 30 miles north of Amarillo. It was found that this dome had an area of over 100 square miles, with a lift of about 500 feet. The first well drilled on this struc- ture encountered gas, and since that time about a dozen gas wells have been drilled on this dome, producing up to 107,000,000 cubic feet of gas daily. Wells drilled on the 6666 dome in Carson and Hutchinson coun- ties have produced both gas and oil. Other domes have proved to be nonproductive. One very interesting thing about these structures is that as more and more wells have been drilled we have learned that they are superimposed upon buried crystalline rocks. The greater number of the wells reach either an arkosic sand or felsite, somewhere between 2,000 and 3,000 feet, and at least two wells on each of the three domes—Bravo, J ohn Ray, and 6666—appear to have penetrated solid granite. Now, by projecting the main axis of the Arbuckle-Wichita uphft to the northwest, it will be seen that these domes are practically in line with this projection; also, there are four granite wells in southwestern Okla- homa and the eastern part of the Panhandle, making in all ten granite wells in practically a straight line with the Arbuckle-Wichita axis.2* In the light of present knowledge, therefore, it would seem safe to postulate a buried granite ridge extending from the west end of the Wichitas north- westward for a distance of at least 200 miles. In this connection it may not be amiss to call attention to the fact that granite has been encountered in wells near Caney, Oklahoma, southeast of the Arbuckle granite. It has been suggested that the Arbuckles, and possibly the Wichitas, are connected with Llanoria.?? At any rate, the line along which crystalline rocks, either surface or subsurface, occur extends from southeastern Oklahoma, along the axis of the Arbuckle and Wichita Mountains, and entirely across the Panhandle of Texas, as far as northeastern New Mexico, a distance of nearly 400 miles. | If a name be desired for this buried mountain range northwest of the Wichitas, perhaps none better can be found than the name “Amarillo Mountains.” Powers has already used the term “Amarillo Hills” describe the buried structures under the oil- and gas-producing structures in this region,”® but he did not include the gap between the 6666 dome in Carson County, Texas, and the Wichitas. SUBSURFACE CRYSTALLINES 55S RED RIVER UPLIFT Powers has also called attention to several granite wells along Red River, in northern Texas and southern Oklahoma, in what he calls the Red River uplift, extending eastward from the Petrolia oil field. The presence of at least five wells, more or less in line, which have reached granite, in this region would lead to the assumption of the possibility of the presence of a buried ridge at this place. Figure 3 shows the location of the Nemaha and Amarillo Mountains and of. numerous wells which have touched granite. BURIED GRANITE RIDGE IN NEW MEXICO John L. Rich has described a “buried granite mountain range under- neath the western margin of the Great Plains, 30 to 70 miles east of the Front Range of the Rockies,” *’ reaching from Corona, New Mexico, northeastward for a distance of nearly 300 miles. Mr. Rich bases his conclusions on certain outcrops of igneous rocks as well as on granite in several wells along the broad geanticline which separates the synclinal basin east of the Front Range from the long monoclinal eastward dip of the rocks across the plains. Regarding this matter, Mr. Rich says in a letter dated December 4, 1922: “East of the Estancia Valley of New Mexico, for a distance of over 50 miles north and south, there are outcrops of granite and other rocks of the base- ment complex which represent the tops of a mountain range which was buried under sediments of Permian age and later partly exhumed. The Hills of Pedernal are monadnocks, near the northern end of the exposed portion. of this range. A few miles north of them, in the area covered by the Permian sediments, several wells have encountered granite at shallow depths imme- diately below the Permian rocks. At the Anton Chico well, township ‘11 north, range 19 east, granite was found at about 2,000 feet immediately beneath the Permian Redbeds. In a well drilled by the Continental Oil Company, in town- ship 31 north, range 33 east, on the broad anticlinal area east of the Raton coal basin, granite was struck immediately below the Redbeds at about 2,500 feet. These facts, taken in connection with the general structure of the re- gion, lead to the conclusion that an extensive mountain range of Pennsylva- nian or early Permian age lies buried under the plains 30 to 70 miles east of the present Front Range of the Rocky Mountains.” MISCELLANEOUS GRANITE WELLS From the map shown in figure 3, it will be noted that there are quite a number of granite wells in the region west of the Ozarks. In Kansas, six wells are reported east of the Nemaha Mountains. In northeastern Oklahoma there are 15 granite wells; also six wells in Missouri and two jot C. N. GOULD——CRYSTALLINE ROCKS OF THE PLAINS in northwestern Arkansas. Some of these wells, as, for instance, two in the Cushing field, are known to be on well-marked anticlines, which have yielded large amounts of petroleum, while others occur where there is little surface indication of structure and where no oil has been found. It must be remembered that out of several thousand wells drilled in southeastern Kansas and northeastern Oklahoma only a very few have ‘ ° = \ gee els On KL AY EO} MS ieee R UE * 1 } ice as ee eae ee Pre-CAmBRiAN CRYSTALLINE S75 ® Weccs Reaching Crrstacuine Rocns FIGURE 3.—Location of buried Granite Ridges in Kansas, Oklahoma, and Texas; also Location of Wells which have reached Granite passed entirely through the sedimentaries. The common interpretation of the presence of granite in these wells is either that they were drilled at a place where the granite basement was comparatively near the sur- face, or that the well chanced to be located over a buried monadnock. I realize very keenly the tendency to derive conclusions from insuffi- cient data, and to postulate buried ridges in likely regions. While it may be a geometrical axiom that three points in a row indicate a straight line, SUBSURFACE CRYSTALLINES 555 it is not necessarily true that three granite wells in a row mark a buried ridge. One might easily take a granite well map of southeastern Kansas and northeastern Oklahoma and draw lines in every direction, some of — which might possibly be located along a buried ridge. The data set forth in this paper have been secured from many sources, chiefly from State geologists and from the chief geologists of the various oil companies, as well as from many private investigators, to each of whom is due my sincere thanks. No pretense is made to completeness in this paper, for new granite wells are constantly being drilled. Doubt- less many wells which have encountered granite have never come to the attention of geologists, while in many other cases the information can not yet be divulged for “business reasons.” This paper must, therefore, be considered nothing more than a progress report. However, it is believed that the locations hereby given will represent in a fair manner our present available knowledge of the subject. LIST OF GRANITE WELLS The following tentative list shows the location and depth of the granite wells of which the writer now has a record, in the States of Nebraska, Kansas, Missouri, Arkansas, Oklahoma, Texas, and eastern New Mexico: Nebraska Depth, feet * Township 1 north, range 12 east 522 Pawnee County. 2 north, range 12 east 600 Pawnee County. 3 north, range 12 east 600 Pawnee County. Kansas Depth, feet Section 36, township 32 south, range east 3,420 Sumner County. iw) 7, township 22 south, range 4 east 3,300 Marion County. 1, township 23 south, range 4 east 3,530 Butler County. 11, township 26 south, range 4 east 2,675 Butler County. 12, township 26 south, range 4 east 2,805 Butler County. 17, township 28 south, range 4 east 2,800 Butler County. 2, township 7 south, range 5 east 2,520 Riley County. 25, township 20 south, range 5 east 3,040 Marion County. 12, township 23 south, range 5 east 2.500 Butler County. 14, township 23 south, range 5 east Zool Butler County. 16, township 23 south, range 5 east 2,139 Butler County. 26, township 23 south, range 5 east 2,545 Butler County. 6, township 24 south, range 5 east Sears Butler County. 5, township 18 south, range 6 east 2,515 Chase County. 2H C. N. GOULD—CRYSTALLINE ROCKS OF THE PLAINS Depth, feet Section 15, township 18 south, range 6 east 2,427 Chase County. 19, township 18 south, range 6 east 2.410 Chase County. 7, township 19 south, range 6 east 2. D85 Chase County. 24, township 15 south, range T east 2,512 Morris County. 11, township 16 south, range 7 east 1,900 Morris County. 34, township 17 south, range 7 east 2.506 Morris County. 24, township 17 south, range 7 east 2,092 Morris County. 4, township 18 south, range 7 east 2,110 Chase County. 34, township 19 south, range 7 east 1,805 Chase County. township 20 south, range 7 east 1,890 Chase County. ea) east 3.470-3,855 Greenwood Co. east 1,850 Pottawatomie Co. east 928 Waubaunsee Co. east 95S8-1,050 Waubaunsee Co. township 27 south, range 24, township 9 south, range 28, township 10 south, range 26, township 10 south, range Ooo © 1, township 11 south, range 9 east 1,180 Waubaunsee Co. 12, township 10 south, range 10 east 2,300 Waubaunsee Co. 19, township 3 south, range 11 east 940 Nemaha County. 34, township 6 south, range 11 east 960 Pottawatomie Co. 6, township 2 south, range 12 east 600 Nemaha County. 6, township 2 south, range 12 east 600 Nemaha County. 22, township 29 south, range 13 east 2,500 Wilson County. .., township 14 south, range 15 east 2,835 Osage County. 17, township 25 south, range 15 east £15 Woodson County. 29, township 26 south, range 17 east 2,405 Woodson County. 3, township 9 south, range 19 east 3,175 Jefferson County. 34, township 29 south, range 19 east 2,035 Neosho County. 29, township 25 south, range 20 east 1,827 Allen County. 16, township 17 south, range 23 east 2.260 Miami County... 13, township 33 south, range 25 east 1,761 Cherokee County. Missouri Feet Phelps County, Rolla o.6% wn. oid Ahn, Seong dead eee ee ee 1,800 Jackson ‘County, Carthage... 6.6 choca ct ee nek eee bas 6 ee oe ee 1.800 Jackson County, FRAYtOWM «oie oon oes oc oe oe ep re mao ohn Se haclede (yunts, Lebanon. 2... 26 6.20. cobs, acento eon eee eee bee 1,900 Howell County, .Pomotia «. ... 6. . se ne f= ca eee a eee 2,000 Arkansas Washington County, township 15 north, range 31 west. Benton County, township 10 north, range 31 west. Oklahoma Depth, feet Section 35, township 19 north, range 25 east 1,776 Cherokee County. 19, township 25 north, range 20 east 1,925 Craig County. 28, township 15 north, range 19 east 3,071 Muskogee County. 34, township 29 north, range 19 easf 2,015 Craig County. Or Ot ~] LIST OF GRANITE WELLS Depth, feet Section 2, township 23 north, range 19 east 1,540 Mayes County. 4, township 15 north, range 18 east 3,235 Muskogee County. 4, township 15 north, range 18 east 2,980-3,037 Muskogee County. 35, township 20 north, range 17 east 480 Rogers County. 14, township 20 north, range 17 east 1,226 Rogers County. 27, township 27 north, range 16 east 2,070 Nowata County. 31, township 22 north, range 15 east 2,765 Rogers County. 30, township 28 north, range 13 east 2,548 Washington Co. 22, township 29 north, range 13 east. 2,500 Washington Co. 25, township 25 north, range 12 east 2,340 Osage County. 22, township 19 north, range 11 east SOs Tulsa County. 25, township 23 north, range 8 east 3,000 Osage County. 22, township 19 north, range 7 east 3,760 Creek County. 22, township 17 north, range 7 east 3,670-3,700 Creek County. 17, township 17 north, range 7 east 3,667 Creek County. 18, township 28 north, range 3 east 4,790 Kay County. 35, township 6 south, range 5 west 2,240 Jefferson County. 14, township 7 south, range 6 west 2,600-2,760 Jefferson County. 15, township 1 south, range 15 west 1,400 Tillman County. 35, township 3 south, range 16 west 2,985 Tillman County. 31, township 6 north, range 17 west 730 Kiowa County. 31, township 4 north, range 18 west 515-700 Kiowa County. 1, township 5 north, range 18 west L232 Kiowa County. 29, township 7 north, range 20 west 3,000 Kiowa County. 34, township 7 north, range 20 west 900 Kiowa County. 8, township 6 north, range 20 west 850 Kiowa County. 17, township 5 north, range 21 west 1,400-1,730 Greer County. 35, township 6 north, range 21 west 380 Greer County. 9, township 7 north, range 22 west 1,640 Greer County. 36, township 6 north, range 22 west 840 Greer County. 27, township 7 north, range 25 west 2,950 Beckham County. 21, township §8 north, range 26 west 2,415 Beckham County. Texas Feet Cooke County, 14% miles northwest of Meunster................. 2,620-2,700 Momacsne County, o miles north Of St, Joe. sss... 0.6 ee se Se ee wn 3,007 Montague County, 7 miles north of Nocona............ Seen ate 2,490 Sie neounminy, “metmOla Tel. se oc fees cise cls ccs hee sce Cece elcuscs'e 4,240 SAE MOUMMny Cet Oia MEM. oisrsetc cc aise cic fic ce cou eclew acces 2,030—2,200 Beer County, Amarillo, -MasterSOn. .........) > ’ 2 Z = —s Ann. Rept. Geol. Surv, Canada, 1894, pp. 66-76 B. ® Geol. Surv. Canada, Mem. 38, part 1, pp. 86-88. 7 Geol. Surv. Canada, Mem. 87, pp. 31-39. .’ Summary Rept., Geol. Surv. Canada. 1912, pp. 140-144. 570 Ww. L. UGLOW—PENEPLAIN IN BRITISH COLUMBIA Owing to the absence of continuous exposures, the extent and depth of this erosion can not be estimated. This block-faulting may possibly be correlated with that period of tension which followed the compressive stresses of the Laramide revolu- tion. Daly® and Mackenzie‘ found similar faulting of the early Tertiary measures along the international boundary and in the Flathead Valley in southern Alberta. It is probable that these crustal movements are all of the same age, and in the North Thompson basin they can be defi- nitely placed between the end of the Eocene and the period of Miocene vulcanism. In reference to the deformation of the peneplain as a result of the Oligocene block-faulting, it may be noted that the western side of the trench is much lower than the eastern; and this may be due to the com- bined effects of the Oligocene and post-Miocene diastrophism. MIOCENE VULCANISM During the Miocene period extensive subaerial floods of andesitic and basaltic lava poured out over the southern intérior of the province. Within the region in question these flows were mostly hornblende- and augite-andesite, usually highly scoriaceous and amygdaloidal. Agate, hyalite, zeolites, and native copper are found as fillings of the amygdules. The lavas flooded the valleys and depressions and covered the upturned and eroded measures of Eocene age. In the valley of the Clearwater River, a southerly flowing tributary of the North Thompson, great ter- races of this lava still remain as remnants from post-Miocene erosion, and underneath the lava may be seen cliffs of bleached and kaolinized granite, the result of pre-Miocene weathering. POST-MIOCENE DIASTROPHISM AND EROSION Further faulting within the trench followed the extrusion and solidifi- cation of the lavas. Along a fault zone running north and south through the center of the trench, the western wall of the valley was down-faulted with respect to the eastern wall. This faulting was accompanied by the production in the lava of closely spaced shearing planes parallel to the strike of the main fault. Owing to the displacement, the flows which overlie the Eocene sediments on the west side of the river are now at the same level as the coal measures of the Eocene on the east bank. The vertical displacement along this fault was at least 600 feet and probably as much as 1,000 feet. Evidence of this faulting is still preserved in OLIGOCENE DIASTROPHISM AND EROSION 5TL the difference of elevation of the upland on the east and west sides of the trench. Erosion, accompanying and following the diastrophism, succeeded in _removing a large part of the lava cap and underlying Eocene sediments ‘from the valley. The only portions of the Miocene lavas which re- mained at the end of the Pliocene consisted of rock terraces rising to heights of 800 feet above the bottom of the valley. The central portion of the trench was reexcavated to a depth about equal to that which ob- tained at the inception of Eocene sedimentation. PLEISTOCENE GLACIATION AND SUBSIDENCE A Pleistocene ice-cap which filled the valley and extended to a height sufficient to glaciate and groove rock hills at an altitude of 7,500 feet covered the southern interior and flowed in a general southeasterly direc- tion. The ice removed the weathered rock from the ridges, deposited erratics and till, and produced a “‘roche moutonnée” effect on the rocky slopes of the valley and intratrench ridges (Mount Ole, Queen Bess Ridge, Fennell Mountains). It supplied to the glacial river great quan- tities of boulders, sand, silt, and mud, which were deposited lower down as a thick valley fill. Thick deposits of white silt (the “White Silts” of Dawson®) were deposited at this time, covering the glacio-fluvial gravels. Remnants of these may now be seen as terraces up to altitudes of 2,250 feet along the sides of the North Thompson Valley. The presence of these silts on top of the glacio-fluvial gravels indicates a submergence of the land surface, probably below sealevel. RECENT UPLIFT, EROSION, AND VULCANISM Following the period of the deposition of the “White Silts” there was a considerable uphft of the southern interior, which caused a rejuvena- tion of the streams. The North Thompson Valley was reexcavated in the unconsolidated Pleistocene sediments, and the ‘White Silts” and glacio-fluvial deposits were carved into a series of finely developed hang- ing terraces. The eroded portions of the unconsolidated formations were reassorted in Recent times and are now found constituting the lower benches and river flats, which are such marked features of the valley bottom. Asa result of this post-Pleistocene or Recent erosion, the North Thompson Valley was again deepened so that its bottom is now in a great many places at approximately the same stratigraphical depth as it was in Middle Eocene and Pliocene times. ® Ann. Rept., Geol. Surv. Canada, vol. vii, 1894, pp. 283-291 B. 5t2 WwW. L. UGLOW——PENEPLAIN IN BRITISH COLUMBIA In the postglacial gorge of Mann or Blackwater Creek, two 10-foot flows of basic lava cover Pleistocene or Recent unconsolidated stream erayels. These flows point to a recurrence of volcanic extrusion in Recent times. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 573-608 SEPTEMBER 30, 1923 GLACIAL DRAINAGE ON THE COLUMBIA PLATEAU * BY J. HARLEN BRETZ | (Presented before the Society December 30, 1923) CONTENTS Page Meeaicr VNC LTRS ene ee ty re eas eae eh tae tamer taictietn: cle rouarencts tele aoa eles “e/ agree 69 a. € aime o73 Moportaphy aNd Grainagse. .. 2... ee ee eet eee steer e eee Shi ee Bias Sa 575 Reaselee MAP ID IAIN, Sree etree ats sieeve eiai e) a cjel s elateie eccliaiie evenale) Rete ects eid ee 28 oe ese 0 66 6 576 Ep EGHIG SoTNIN hiya nie Wales saeiatecsto nests, = eyeetehaOs oe sfaia ec woes sce Pas sien ies si ae be es eee s DTT Mele eae AETEN INET aren Saeed Nea ae oe one erae ae) arcsec scones aie @ Simard aiehace @ af eie ahlere #0 Faia we 580 SEES PONCE # SUACTALTOIN. «2c. 4 5 = os cies core le The floor of each of the cols is on basalt at about 2,450 feet above tide and is essentially a scabland tract. ‘The glacial waters back of this double spill- way doubtless were ponded in Latah and Rock Creek valleys. During the occupation of the spillways these waters eroded deeply in the basalt. The larger spillway is half a mile wide at the col. Both are well shown on the Oakesdale topographic map and on -the Spokane County soil map. Near the junction of North Pine Creek and Pine ° Thomas Large: The glaciation of the Cordilleran region. Science, vol. 56, no. 1447, L922 Dewey: 584 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU Creek and in the larger valley are great bars and terraces of coarse basaltic gravel, poorly sorted and much of it subangular. Mingled with it are a few cobbles and small boulders of granite and quartzite. The material farther down Pine Creek Valley is finer and better sorted. It seems clear that most of the debris was derived by erosion of the spuill- ways themselves, only a small amount of foreign material crossing the lake on ice-rafts from the front of the ice-sheet. The valley during this episode in its history was but a channel. The elacial stream filled it from side to side for a depth of tens of feet. This _ is shown a few miles above Malden, where the stream flooded over a low shoulder of basalt, cutting a channel in the rock at least 40 feet deep, though the main valley alongside was wide open and received gravel deposits. North Pine Creek now flows through this channel. The main current of the stream here cut across a curve in the preexisting valley. The gradient of this glacial stream was close to 30 feet to the mile in its upper part and about 20 feet to the mile in the lower part. | The character of the terraces in Pine Creek Valley below the junction of North Pine Creek is instructive. Like the Pantops deposit, there are no well defined depositional forms. The terrace tops do not abut sharply against the hillslopes, but instead waste has crept out on the gravel de- posits from the slopes above, and the valleyward edges of the terraces have become rounded and notched by widened gullies until the terrace form is obscure. This is well shown at Kenova, where the Chicago, Mil- waukee and Saint Paul Railroad has opened a large pit in the gravel. Furthermore, these terraces are only fragments here and there of what was once a continuous filling. Despite these evidences of considerable age, the material in the deposits appears fresh. It is unstained and uncemented. Only one other glacial drainage route across the mature Palouse coun- try is known, and this was but a tributary to the Pine Creek channel. Waters from glacial ice spilled southward through a low place at Miea between Moran Peak on the west and Mica Peak on the east. The alti- tude of the col at Mica is hardly 10 feet above that southeast of Spangle. Ponded waters of the Latah Valley must have backed up almost to the village of Mica. Whether or not a considerable lake Iay to the north of the Mica col,® it is certain that the ice-sheet was hard against the north- ern flank of Moran Peak and its drainage probably passed through a settling basin before entering the short Mica channel. A few erraties, one of them striated, have been found in the channel, but no glacial ®**Lake Spokane’ of Large. THE SPOKANE GLACIATION 58a stream gravel. Nor was the Mica channel eroded to any extent. Prob- ably ponded waters were backed up from the south until the last stages in erosion of the North Pine Creek channel. Vicinity of Cheney.—Cheney lies 15 miles southwest of Spokane and 10 miles northwest of Spangle. About this town are recognizable the same elements in the topography as already outlined—the higher pre- basalt hills, the Palouse type of maturely dissected hills, and the lower scablands. The scablands have less relief than either of the other ele- ments, but are much rougher. They are commonly a maze of minor channels and depressions eroded in the basalt. Cheney lies at the head of the largest tract of scabland on the pla- teau—a tract which extends from Spokane River to Snake River. It is not uninterruptedly scabland, however. It contains isolated groups of Palouse Hills. One of the largest of these groups lies immediately north of Cheney and has an area of about 13 square miles. Many of them are not a square mile in area. In topography and in soil, these tracts are identical with the Palouse wheat country to the east and southeast; but the gentle, concave lower slopes of maturity, so characteristic of these hills, is absent on the peripheries of the isolated groups. Instead, these outer slopes are much steeper and are generally convex. They meet the roughened plain of the scabland with a definite angle. The bounding slopes clearly are much younger than the valley slopes among the hills. The hill groups are elongated northeast-southwest, in harmony with the elongation of the channels on the basalt surface and with the scab- land tract as a whole. In many of these linear groups there are longi- tudinal valleys, not of the mature type, but with steep sides and scabland floor. All such valleys pass completely through a hill group, leading from the rocky plain into the rolling hills and out again to the plain. Another feature of this great scabland tract is the presence of many widely scattered granite boulders. Nowhere (with one exception, to be detailed later) has this foreign debris been found back among or on the slopes of the hill groups. Associated with it, but much less common, are terraces of gravel composed largely of basaltic debris, but with granite and other foreign material distributed through it. Such deposits commonly le on the southwest sides of recky shoulders or hills in the channels. They have been opened for railroad ballast and road metal at many places over the whole scabland area. _ From a survey of the patches and groups of the Palouse Hills scat- tered over the scabland plain south of Cheney, it seems clear that they are but remnants of a once continuous cover of the basalt, and that the scablands have resulted from remoyal of the Palouse Hills by erosion in 586 J.H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU some unusual way. The basalt of the scablands is the firm and resistant foundation on which the hills stand. The overlying sedimentary deposit is the formation whose etched surface constitutes the hills. The seabland does not extend north of the Palouse Hills about Cheney and Medical Lake, though it does extend among them in great river channels to their northern limits. Farther north, there is neither scab- land nor Palouse Hills. The area is a basalt plain with widely spaced mature valleys and broad, low, flat divides. The whole is thinly covered with glacial drift, some of it a stony till with hummocky morainic topog- raphy, some of it washed and stratified glacial sand and gravel. The ice-sheet clearly covered this plain. It, however, did not extend south- ward into the scabland area, except for a minor lobe between Moran Peak and the Cheney Hills, which reached as far south as Spangle. The asso- ‘ciation of broad undissected divides with shallow, mature valleys, all in resistant rock (for example, Deep Creek and its tributaries) is anoma- lous. It is believed to be the result of the glaciation of a tract which possessed a typical Palouse mature topography, developed largely in a silt or ash deposit, but etched in the deeper valleys into the surface of the underlying basalt. The ice removed every trace of the hills in the weaker formation, bringing the whole down to the surface of the basalt ; in effect, it cut off the hills well down to their bases without greatly modifying the main valley bottoms. Vicinity of Lamont.—Twenty miles to the southwest of Cheney the escaping glacial waters had become largely concentrated between Sprague and Lamont. The eroded tract here is nearly 10 miles wide and without a surviving Palouse hill. A sheet of torrential water must have spread completely across the scabland between these two towns. It rapidly re- moved the weaker material of the Palouse Hills and then scoured out channels in the basalt. By the close of its occupancy it had concentrated in certain channels and eroded them approximately 100 feet below the surface of the basalt. Colville (Sprague) Lake lies in one of these channels. Between Lamont and Rock Lake, to the east, is a linear tract of Palouse Hills about eight miles wide and traversed by but one valley possessing bare rock in its floor and scattered granite fragments. Sepa- rating this tract from the Palouse country of Whitman County is a great river channel, occupied now by Rock Creek and several elongated lakes. Rock Lake is the largest of these and, save one, is the largest and longest lake on the Columbia Plateau of Washington. Rock Lake (see figure 5) is bounded on both sides by sheer cliffs of basalt 200 feet and more in height. There is no damming of consequence in the channel at the lower THE SPOKANE GLACIATION ee tiene end of the lake. Rock Lake exists because the ancient river here exca- vated more deeply in its bed than it did a little farther down stream. Rock Lake is typical of most lake basins of the Columbia Plateau in Washington, in that it is a much elongated true rock-basin in an ancient river channel in a scabland area. The only part played by glacial ice in the formation of these basins is that of supplying the stream. Factors essential for development of these rock-basins made by streams are (1) large volume abruptly introduced, (2) high gradient, and (3) rock which is closely and vertically jointed. The excavation was accomplished by plucking, rather than by grinding. Vicinity of Kahlotus—About 25 miles south of the latitude of Rock Lake the scabland is more restricted. So far as now known, all channels but one entered Snake River in the vicinity of the present junction of the Palouse. The one channel which escaped the control of the Palouse system is traceable westward, by way of Washtucna, through Kahlotus, to Esquatzel Coulee at Connell. It is a splendid abandoned channel, in places 250 to 300 feet deep. Throughout its length it has all the char- acters of the channels of the scabland tract to the east and northeast except that it does not le in such a tract. It probably was sufficiently deep at the inception of the flood to contain the waters which came its way. A few miles above the junction of Washtucna Coulee, Esquatzel Coulee has none of these characters, but possesses the broad, graded slopes of maturity. Vicermiy of Sprague.—The westernmost channels among the Palouse Hills near Cheney which discharged to the Palouse system enter the broad scabland between Sprague and Fishtrap. The roughness of these channel floors, due to the gashed basalt, is in striking contrast with the smooth flowing contours of the inclosing hills. One needs but little imagination to see again from these hilltops the torrents of glacial waters invading from the north and following the lower valleys southward to jom the scabland between Sprague and Lamont. These hills, like those im the Palouse wheat lands, are composed largely of a fine-tertured unindurated sediment, probably of lacustrine origin.’ It does not seem probable that any water, other than that which occu- pied Washtucna Coulee, escaped westward from the Palouse drainage during the Spokane epoch. There are two possible routes, however, of such discharge, namely, one by way of Keystone, near the lower end of Colville (Sprague) Lake and Ritzville; the other by way of Ralston. Both enter Lind Coulee at Lind. The altitude at the head of the Ritz- “M. R. Campbell: Guidebook of the Western United States. Part A: The Northern Pacific Route. U.S. Geol. Survey, Bull. 611, 1915, p. 163. 588 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU ville route is 53 feet above the surface of Colville Lake in the adjacent scabland, and Ralston is not 100 feet above the floor of the Cow Creek channel. Along both routes are deposits of stream gravel.* Yet no scour of the floor by glacial waters, nor steepened valley walls, nor scattered erratic boulders or cobbles were seen.® It is possible that these routes were used for but a short time early in the glacial flooding, or it may be that the gravels are older than the Spokane glaciation. It may be, also, that the gravels in channels near Winona and Lacrosse, south of Rock Lake, are of pre-Spokane age. 3 The scablands of the Palouse drainage, with channeled basalt, deposits of stratified gravel, and isolated linear groups of Palouse Hills, their marginal slopes steepened notably, bear abundant evidence of a great flood of glacial waters from the north. This flood was born of the Spo- kane ice-sheet. Its gradient was high, averaging, perhaps, 25 feet to the mile, and it swept more than 400 square miles of the region clean of the weaker material constituting the Palouse Hills. The hills which have disappeared averaged 200 feet in height, and in some places the glacial torrents eroded 100 to 200 feet into the basalt. This flood originated at several places along the ice-front. Great river channels exist among the remaining hills in the flood-swept region. The area overridden by the ice itself has lost every trace of Palouse Hills.?° CRAB CREEK DRAINAGE General statement.—By at least ten different routes, glacial waters from the Spokane ice-sheet west of Cheney and Medical Lake converged to Crab Creek. Another discharge way, still farther west, that of Moses Coulee, found its own way to the Columbia above the entrance of Crab Creek drainage. The glacial streams tributary to Crab Creek, named from east to west, were Rock Creek (Lincoln County), the headwaters &’M. M. Leighton: The road building sands and gravels of Washington. Wash. Geol. Survey, Bull. 22, 1919, pp. 104-105. Leighton clearly recognizes that the Spokane re- gion had been glaciated (p. 246), that numerous glacial drainage courses exist on the plateau (p. 34), and that the scablands are due to erosion of the sedimentary material by escaping glacial waters (p. 279). * Campbell. op. cit., also notes the absence of the granite boulders along the Northern Pacific Railroad, which follows the Ritzville route, west of the lower end of Colville Lake. 1 Explanation should here be made of certain glacial deposits which are older than te Spokane drift. In an abandoned clay pit near the Cheney Normal School is a very old clayey till first reported by Frank Leverett (Bull. Geol. Soc. Am., vol. 28, 1916, p. 143). It contains striated quartzite boulders and cobbles. One such boulder also has fine chatter-marks on it. Granite is present, but is crumbling or etched to such an ex- tent that no ice-marked surfaces remain. This till also is exposed along roadsides south and east of Granite Lake, and striated erratics have been found back in the mature valleys of this hill group. It seems probable that the old till underlies much of these THE SPOKANE GLACIATION 989 of Crab Creek, Coal Creek, Duck Creek, Lake Creek, an unnamed creek west of Lake Creek, Connawai Creek, Wilson Creek, Spring Coulee, and Grand Coulee. The first eight originated from the ice on the northern rim of the plateau between Hellgate and Medical Lake. The other two entered the plateau from the Columbia Valley by one route, upper Grand Coulee, and separated at Coulee City. The location of the edge of the Spokane ice near the head of Grand Coulee is as yet unknown. The glacial river courses are all youthful canyons in basalt. They are quite unlike the associated drainage lines of comparable length which never received glacial waters and which are typical valleys in maturity. The youthful canyons, however, were not eroded by the streams which occupy them. Despite their size, most of them are but the deepened channels of ice-born rivers, and not true valleys. Like the scablands of the Palouse region, invading, but short-lived, floods traversed the area; but they failed in the main to produce broad, stream-scoured surfaces of bare rock. Where they entered preglacial valleys in basalt they were not able to broaden them much, Extensive scablands have been formed only where the preglacial drainage pattern was eroded in a weak, super-basalt sedimentary deposit. The limits reached by the Spokane ice-sheet west of Cheney and Med- ical Lake are not well known, since there is no morainal ridging along the margin. The approximate boundary, as shown on the accompanying map, has been located along the southern hmits of a basalt plain with much bare rock and a scattering of glacial debris. South of this margin are unglaciated loess-covered hills of mature aspect and the scoured, and in many places canyon-like, glacial drainage channels. The limits as drawn are, perhaps, too far south in places. The ice is not known to have crossed the Columbia between Hellgate and the head of Grand Coulee. It did cross, however, in Douglas County, farther west, and ad- vanced far enough to discharge its waters into Moses Coulee. The Wis- hills. The till is covered with several feet of loess at Cheney. The loess is deep on all Palouse Hills of eastern Washington, but does not occur on the seablands or on the glaciated plain to the north. It therefore is older than the Spokane glaciation. Since this Cheney till is beneath the loess and probably underlies the Palouse Hills, it is much older than the mature topography. There is no more suggestion of glacial over- riding in the shapes of these hills north of Cheney than there is in the typical Palouse region of Whitman County. On the other band, certain large pre-basalt hills west of Medical Lake, rising high above the Palouse Hills of the region, do show a prevailingly steep northern slope and gentle southern slope, as though they had been overriden by glacial ice. If this profile has had such an origin, it must be ascribed to the pre-Spokane, pre-loess glaciation. The glacial till reported by Pardee (op. cit.) at ‘‘scores’’ of places over large parts of Lincoln, Spokane, and Adams counties, and as far south as Kahlotus, probably is simi- larly related to the loess which deeply mantles the Palouse Hills of those counties. 590 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU consin glaciation of northern Douglas County was more extensive than the Spokane and obliterated all records left by the Spokane ice. There are scablands in the northern part of some of these spillways, notably between Davenport and Rocklyn and in the vicinity of Telford. The detailed relations of the largest, at and southwest of Telford, are not yet well known; but concentration in preexisting valleys in basalt was completed in most cases within 10 miles or so of the edge of the ice, and rock-walled canyons with elongated lakes in the bottoms are the rule. _ The altitudes of the heads of these spillways are not the same, and had not the ice been hard against the unglaciated hills south of the basalt plain, marginal drainage would have carried all waters to the lowest of the group. Gravel deposits and scattered granite boulders and cobbles are well distributed in these coulees. Gravels are chiefly of basalt and appear as fresh as in the scablands of the Palouse drainage. The terrace forms are indefinite, wide-open gullies have dissected them, and they are but rem- nants, perhaps miles apart, of former probably continuous fillings. This also is comparable to the gravels of the main Palouse channels. Because of the prominence of cliffs in these canyons of Crab Creek drainage, another feature is well presented—the talus piles which have formed since the glacial streams abandoned their channels. The cliffs are, without exception, composed of the Columbia lava, and, with very few exceptions, the flows are horizontal or but gently inclined and possess columnar jointing. The conditions of origin produced essentially ver- tical cliffs, and the rock structures and arid climate have maintained vertical faces during all subsequent wasting of the cliff and growth of the talus. Except in Grand Coulee and Moses Coulee, which carried Wisconsin glacial waters also, these canyons have been occupied by inconsequential streams since the Spokane glacial floods subsided. The present talus, therefore, is a measure of all post-Spokane disintegration in the vertical walls of jointed lava. In the great majority of cases the talus extends from the rock-floor of the canyon three-fourths to four-fifths of the way to the top (see figures + and 7). In the lower cliffs it has climbed even nearer the summit, and rarely the cliff has become obliterated by the mounting waste. The talus slopes range between 20 degrees and 30 de- grees, with the average probably between 25 degrees and 30 degrees. Since conditions of origin, of rock structure, and of climate are suffi- ciently alike in the Crab Creek and Palouse drainage areas, it follows that relative proportion of talus on cliffs of comparable height may be a valuable criterion to establish more firmly the contemporaneity of glacial THE SPOKANE GLACIATION . 591 drainage in the two areas. The cliffs of the Palouse scabland, though less prominent on the whole than those of the Crab Creek canyons, every- where possess the same average ratios of talus height to depth of channel and the same degree of slope. Further use of this criterion will be made when the Wisconsin glacial drainage channels are examined. Grand Coulee-—Grand Coulee heads in the south wall of Columbia Valley, about 550 feet above the river. At its head it is 1,000 feet deep and about 3 miles wide. In the middle of this valley, 10 miles from the Columbia, stands Steamboat Rock, a basalt mesa with its square mile of summit area at the general altitude of the plateau on either side of the coulee. There are also numerous pre-basalt hills of granite on the floor between Steamboat Rock and the Columbia, formerly buried in the basalt = FIGURE 7.—Post-Spokane Talus in “The Potholes” south of Trinidad and later exhumed in the erosion of the coulee. About 13 miles from the head the canyon narrows to about 2 miles and maintains this width and a depth of about 800 feet as far south as Coulee City. Here the canyon form is lost for 4 or 5 miles, the eastern wall descending, because of a monoclinal flexure, until it is not more than 200 feet above the floor of the coulee. In this broadened portion is a great abandoned cataract with a fall of 400 feet. The width of the falls is nearly 3 miles, the full width of the bottom of the coulee; but it was broken into two different parts in its later history through erosion of the floor above the falls. A central portion of the earlier floor, which escaped much of this erosion, became an island on the brink. The western half, Dry Falls or Grand Falls, is the more definite and in itself was a double fall at the close of the history of this great cataract, with a “Goat Island” in the middle. No water now flows over these falls except in times of heavy rain. 592 +=J.H. BRETZ—GLACIAL DRAINAGE ON: COLUMBIA PLATEAU Below the falls the coulee again becomes a canyon, both because of the gorge left by retreat of the falls and because the basalt surface rises in that direction. For 15 miles or so this lower coulee is a wild, spectacular feature, its western wall fully 1,000 feet high and its bottom less than a mile in width. For most of this distance the ancient river flowed on the strike of a monoclinal fold the dip of which averages 45 degrees and is to the southeast. The falls took origin where the glacial stream passed from horizontal flows to the tilted structure, about 3 miles below their present location. Grand Coulee debouches in a broad, shallow structural depression, the Quincy basin. Into this same basin discharges Crab Creek, which carried the combined flow of all of the glacial rivers previously listed. As above outlined, Grand Coulee is a relatively simple affair, with two canyoned portions separated by a shallower part, due to local structural conditions, with a remarkable waterfall in midlength and with a part of its lower course along tilted flows; but the preglacial conditions and the glacial history are not as simple as in the region farther east. There is no evidence of a preglacial drainage line along the upper canyon between Coulee City and the Columbia. There are but two tributary gorges in the 30 miles of this canyon and these are short and youthful. A mature topography, untouched by glacial ice or water, les on the plateau to the east, with no drainage lines leading to the coulee. To the west the plateau was glaciated to the edge of the coulee during the Wisconsin epoch, but preglacial topographic features still control and give no suggestion of drainage toward the coulee. Moreover, the altitude of the basalt on the precipitous edge of the canyon is about that of the Columbia River-Crab Creek divide; and on both sides of the coulee, near the head, especially well shown on the unglaciated east side, is a scabland tract (see figure 3), with the mature hills gone and the basalt etched and roughened by a maze of anastomosing minor channels and rock- - basins, separated by low buttes and knobs. Elongated meadows, and even lakes, mark some channel courses. No channels are more than 75 feet deep. Glacial erratics of diorite, argillite, slate, schist, and quartzite occur here and there. Especially significant is the talus, which has climbed three-fourths to four-fifths of the total original heights of the channel walls and nowhere is steeper than 20 degrees. On the east side this summit scabland is 3 miles wide, as wide as the floor of the coulee itself, but 1,000 feet higher. The altitude here is about 2,500 feet above tide. In order that glacial waters should have spilled across this place, the ice-sheet must have blocked the Columbia, both to the west and the east, THE SPOKANE GLACIATION - 593 else lower routes in either direction would have taken the discharge. That it was the Spokane ice-sheet is evident from the amount of break- ‘ing down of cliffs since the waters ceased to flow. Searching over the basalt, the wide glacial stream finally selected its central portion, now Grand Coulee, for deeper trenching and withdraw from the margins. Only Steamboat Rock records any of the original anastomosis. ‘To what depth the Spokane waters cut in upper Grand Coulee will be discussed under the subject of Wisconsin glaciation. Hartline structural valley—The monoclinal flexure along which much of lower Grand Coulee is eroded swings toward the east about 2 miles north of Coulee City and extends beyond Almira toward Hellgate. An- other fold, anticlinal in character, lies nearly parallel with it, about 5 miles to the south. The tract between is structurally and topographically a valley and contains a gravelly plain approximately 40 square miles in area. The floor of the coulee at Coulee City is only 200 feet below this flat, and the entire descent to the town from the flat is across gravel. Wells on the flat penetrate sand and gravel to comparable depths. The drainage of the Hartline gravel plain is largely southward through Deadmans Draw, a tributary of Spring Coulee, 10 miles east of Grand Coulee. Deadmans Draw’is but the deepest and most pronounced of a scabland complex of abandoned channels, basins, cascades, and falls, identical in character with and very similar in proportions to those on the plateau along the east side of the head of Grand Coulee. Talus de- velopment is the same. Furthermore, the patchy gravel deposits and stranded erratic boulders tell unequivocally of glacial waters escaping southward across the rim of the structural basin. Hast of Deadmans Draw, as far as Wilson Creek, are gently rolling hills with concave lower slopes and deep loessial soils, which have never been touched by invading glacial waters; but between the draw and Grand Coulee to the west, and from Coulee City south to Bacon Station, a dis- tance of 8 miles, is a tract which for wild ruggedness is unsurpassed any- where among the glacial spillways thus far described. The channels are canyons and the knobs are hills 100 to 300 feet high. Stream gravel covers the interchannel hills. The whole area was overrun by the glacial flood out of the Hartline structural valley. Besides this, at least three of the channel canyons lead owt of Grand Coulee below the falls, but at about the level of the floor above the falls. It is magnified scabland of the Palouse type. One of these channels leads to Spring Coulee, the others converge to Dry Coulee, a small feature debouching into the Quincy structural basin 5 miles east of the mouth of Grand Coulee. Some of these are truly distributary canyons. They mark a distrib- XXXIX—BULL. GEoL. Soc. Am., Vou. 34, 1922 594 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA’ PLATEAU utive or braided course of the Spokane glacial flood over a basalt surface which possessed no adequate pre-Spokane valleys. Greater erosion in the tilted basalt on the western margin of this tract finally drew these waters’ off and down into what has become the lower canyon of Grand Coulee. There is evidence at the lower end of Grand Coulee that a short pre- Spokane valley was entered a little north of Soap Lake. This lake lies at the mouth of the coulee, where the canyon crosses a low anticline. The syncline between it and the main monocline to the north is low and wide open as a structural valley at the east to the Quincy basin. Some drainage did go through here, but most of it crossed the anticline—a thing which would not have been possible if an antecedent drainage line had not existed at this place. The original slope on which the glacial waters flowed from the Colum- bia Valley to the Quincy structural basin was steplike in a general way, a steeper descent existing between the plateau summit to the north and the: Hartline basin, and another such on the northern margin of the Quincy basin. These steeper slopes were determined by structure, though they did not conform exactly to it. The monoclinal fold north of the Hartline basin has a maximum dip of 30 degrees. If the slope which the Spokane waters found was only one-third of this, that glacial river, in effectiveness over this stretch, must have been an enormous mountain torrent. The vertically and closely jointed basalt must have heen eroded with great rapidity, and, where favorable conditions for Sapping were discovered in the channels, falls developed and retreated much more rapidly even than Niagara. While the talus in the higher abandoned channels reaches up three- fourths to four-fifths of the total original height of the cliffs, that in Grand Coulee itself is only halfway up the cliffs (where the flows are horizontal) and has an almost invariable slope of 35 degrees. It clearly dates from the Wisconsin glaciation, not the Spokane. Quincy Valley or Basin.—The Quincy structural basin is bounded on the south by the Frenchman Hills anticline, but its drainage escapes southward around the east end of this fold. All glacial drainage routes of the plateau west of Medical Lake, except Moses Coulee, have been traced to it. Hnormous quantities of basaltic debris have been swept out of the hutidreds of miles of such channels and into this catch-basin. The fill covers 600 square miles and the maximum known thickness is about 400 feet. The lower three-fourths of this fill is clay, silt, and sand, doubtless lacustrine in origin. In this have been found shells of fresh- water boreal mollusks.** Only the upper 100 feet, approximately, are 1 Schwenneson and Meinzer: Ground water in Quincy Valley, Washington. U. S. Geol, Survey, Water Supply Paper 425 BE, 1918, p. 143. THE SPOKANE GLACIATION 59D river gravels. About the margin of the basin the gravel is thinner and rests directly on the basalt. The aggradational plain now is dissected by stream-cut valleys which lead southward to a group of very irregular channels eroded in basalt around the eastern nose of the Frenchman - Hills anticline and thence west to the Columbia between this fold and the parallel Saddle Mountains anticline. Though this drainage line is named Crab Creek, no surface waters from Crab Creek above the Quincy basin now reach it. Dunes of basaltic sand have closed the lower part of these converging valleys and thus formed Moses Lake. The group of channels around the end of Frenchman Hills anticline will here be termed the Drumheller channels (see figure 8). The altitude of the basalt floor at the head of these channels is 950 feet and the high- est altitude over which the water clearly flowed is about 1,200 feet. The group begins as three canyons of nearly equal dimensions, but for most of its length only two dominant canyoned channels exist, one containing a narrow elongated lake, the other containing Crab Creek. The depth of these canyons averages 200 feet. The whole area, however, is scored and gashed by hundreds of similar smaller channels. The two main gorges separate on an accordant level and unite 4 miles downstream, again accordantly, but 100 feet lower than their point of separation. South of the Frenchman Hills anticline, Crab Creek Valley turns abruptly west and follows the syncline between this fold and Saddle Mountains anticline to Columbia River at Beverly. A capacious, unin- terrupted old river course of low gradient exists along this syncline. It is repeatedly referred to in the literature as the lower part of the Grand Coulee route of the diverted Columbia; and certainly the stream which eroded the two dominant channels of the Drumheller plexus took this course; but at an earlier date, before the present Drumheller channels had been eroded, glacial waters also continued directly southward to pass the east end of Saddle Mountain anticline as well. Channeled scabland and stream gravel with granitic material cover 150 square miles of the region south of the end of this fold. As in the Palouse scabland, hills of mature topography and deep soils, developed in a weak sedimentary (presumably the Ellensburg formation) above the basalt, flank the scab- land and are isolated in it. Some of the glacial waters entered Esquatzel Coulee and some went by way of Koontz Coulee to the Columbia near Ringgold. Indeed, Esquatzel Coulee below Connell has been eroded in the scabland subsequent to the maximum flooding.- The waters around the tip of the Saddle Mountain anticlinal nose never cut deeper than 900 feet above tide, while the head of the syn- clinal course just below the Drumheller plexus is eroded in basalt to 700 596 J.H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU io aA i OS a ee aN : ay FIGURE 8.—Part of Drumheller Channels Plexus Channels indicated by arrows; rock-basins in black. THE SPOKANE GLACIATION 597 feet above tide. Using the criterion of talus accumulation, most of the Drumheller channels and the existing synclinal river valley date from the Wisconsin glaciation, while the spillway around the east end of Saddle Mountain was formed during the Spokane glaciation. Chan- neled scabland also lies east of the youthful Drumheller channels and at a higher altitude. It apparently belongs to the Spokane spillways. It appears, therefore, that when Spokane waters escaped southward from the Quincy basin there was no noteworthy valley for lower Crab Creek and, as in the Palouse country, the flood spread out and found its way among the hills of weaker rock. These hills were removed in the Drumheller tract for a width of more than 10 miles. South of Saddle Mountain the width of the scoured tract is equally great. The flood separated into two parts after passing Frenchman Hills anticline, part continuing south to Esquatzel and Koontz coulees and part turning west in the Beverly syncline. The westward course was eroded more deeply than the southward, so that when, in the succeeding Wisconsin diversion, another flood swept through the Drumheller plexus all of it went. west- ward. The striking features of the present plexus, adjusted to the floor of the synclinal route, were then produced. Two other outlets for the Quincy basin existed during the Spokane epoch. They are at Frenchman Springs and “The Potholes,” two great notches in the wall of Columbia Valley on the western margin of the plateau. Hach is an abandoned cataract, to which short channels lead across the western rim of the Quincy basin. “The Potholes” is the best example mapped of a receding waterfall over lava flows which is known to the writer (figure 9). The ancient stream spilled over the Columbia cliffs at an altitude of about 1,200 feet above tide and descended at least 400 feet over two great rock terraces, each with a scarp of about 200 feet. In the upper cliff is exposed a very conspicuous flow with exceptionally large, well developed, and uniform columns approaching 75 feet in length. The flow which holds up the edge of the lower rock terrace is more than 100 feet thick and is composed of uniformly small columns from bottom to top. _ The amount of recession in the waterfall is quite unequal in the two rock terraces. In the upper the cataract was double from its beginning, the two parts being nearly equal and receding side by side for nearly two miles. This parallel recession left a great blade of rock a mile and a half long, 1,000 feet wide, and 375 feet in maximum height between them. A huge elongated pothole was left by the recession of each member of the twin upper falls, deepest and widest below the falls. There are great gravel bars in these potholes, especially in the downstream portions. The one below the southern fall is 200 feet thick (figure 10). 598 J. HH. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU UOPDULYSD AL POPYULAT ADI u «S910Y20T IUD 55- ‘ 6 Bhecascecisriceretns nok stvcerusnuies SS 5 BOT es THE SPOKANE GLACIATION 599 The lava flow which causes the lower rock terrace is much more resist- -ant to plucking and sapping than is the upper terrace. This is shown both in the Columbia Valley and in “The Potholes.” The current which emerged from the Potholes themselves spread considerably over this ter- race and spilled over its edge in a broad sheet which later became some- what concentrated in four or five different places, so that minor notching of the edge of the terrace resulted; but none of these notches was cut back more than a quarter of a mile. 7 Above and east of the upper falls is a scabland tract extending two miles farther east across the low rim of the structural basin and very much diversified by ramifying channels and their separating hills. Rock-basins are common, some of them being 40 feet deep. This chan- FIGURE 10.—One of “The Potholes” The gravel bar (terrace on left) is 200 feet thick and the cliff back of it is 200 feet high. View is taken looking toward the ancient cataract. neled tract was an island-studded rapids descending to the brink of “The Potholes” cataract. At the beginning of the cataract this channeled area extended to the original edge of the upper terrace. As the twin falls, narrower than the channel group, receded eastward, some of these channels were left along the edge of the gorge. The talus accumulations of “The Potholes” are somewhat irregular in height, because of unusually marked differences among the flows in the cliffs, but the large majority constitute three-fourths or more of the total height of the cliffs (see figure 7). “The Potholes” cataract was formed at the time of the Spokane glaciation by discharge from the Quincy basin. The Columbia Valley here was nearly or quite as deep at that time as it is today. The structural basin was agegraded to the level of this western rim and gravel was carried completely across from 600 J. 4H. BRETZ—GLACIAL DRAINAGE ON’ COLUMBIA PLATEAU Crab Creek and Grand Coulee. “As in the Hartline structural basin, the Spokane floods found the depression only partially filled, but left it brimming over with waste. The Frenchman Springs cataract, 8 miles an of “The Potholes,” functioned at the same time and developed a double fall also, but carried a smaller quantity of water. The northern of the two falls here outran the southern in its recession and at the close of the history of the cataract was carrying all of the discharge. Why did not Wisconsin waters use the Frenchman Springs and Pot- holes cataracts? There are two possible answers: (1) Spokane dis- charge through Drumheller Channels eroded this spillway more than it did the rapids above either of the two cataracts, and (2) post-Spokane but pre-Wisconsin warping depressed the Drumheller tract relative to the channels above the two cataracts enough to cause complete Wisconsin diversion to the southern route; and, of course, it is possible that some combination of both occurred. MOSES COULEE This coulee (not to be confused with the valley which contains Moses Lake) ranks second in spectacular proportions only to Grand Coulee. It hes a few miles west of Grand Coulee and leads southwestward directly to the Columbia, 10 miles above “The Potholes.” Its length of 40 miles is divisible into three portions, an upper and a lower canyon separated by a broad, shallow tract in a synclinal valley. The upper canyon is eroded in the gentle southward dip slope of this part of the plateau. Its depth averages about 200 feet. Dip of the basalt is greater than descent of coulee floor. The inclosing walls thus become lower until they vir- tually disappear and the floor of the canyon becomes the floor of the synclinal valley. Here the coulee turns abruptly to the west and follows the axis of the syncline for 6 miles. At Palisades it turns southward again and leaves the syncline to cross a broad uplifted area, or flat-topped anticline, the Badger Mountain fold. The lower canyon across this fold is 900 feet deep. The lower canyon has been extended upstream by headward erosion about half the length of the synclinal portion. Here it abruptly ends at the foot of a cliff across the coulee. Two great castellated buttresses face clown the coulee, with lesser walls connecting them. This notched cliff clearly was a waterfall, and before the deep notching it was comparable in height to Grand Falls at Coulee City. From this transcoulee cliff to the lower end of the upper canyon is a tract, 5 or 6 miles long and nearly as wide, where the basalt floor of the syncline was widely overrun by a great stream which formed a complex THE SPOKANE GLACIATION 601 of anastomosing channels with rock-basins and cataracts, leaving isolated knobs and buttes irregularly disposed in a perfect maze (see figure +). Bare rock or rocky talus covers the area, whereas both canyoned portions have no rock-floor exposed. There is a total descent of 600 feet along this tract. Most of the channels have noteworthy talus accumulations, amounting to three-fourths or four-fifths of the total depths. Only the lower and central channels bear talus comparable to that in Grand Coulee and Drumheller channels. Erratics of granite, quartzites, etcetera, he here and there, even on the highest of these eroded surfaces. In the upper canyon, north of the moraine built by the Okanogan lobe during the Wisconsin glaciation, talus is but halfway up the cliffs. Be- low the moraine some talus piles seem to be of Spokane age, some of Wisconsin, and there is other evidence that Wisconsin waters only par- tially cleaned away the preexisting cliff waste. In the lower canyon the talus dates back to the Spokane epoch. If there is any record of Wis- consin waters, it is in the gravel fill, more than 200 feet deep, 3 miles from the head of this canyon, and possibly in the existence of a promi- nent rock terrace, not more than 100 feet above the aggraded floor of the canyon, a few miles south of Palisades. If trenching by Wisconsin waters was performed anywhere in the lower canyon, it was in the production of this terrace. _ Moses Coulee, as a drainage line, antedates the Spokane glaciation. Tributary valleys, well developed in the basalt, are recognizable as far north as Mansfield, and the upper canyon itself extends 6 or 8 miles north of the Wisconsin terminal moraine; but the best evidence is in the lower coulee. The cliffs here are deeply notched by wide-open V-shaped tributary valleys. Many notches are two-thirds or more as deep as the main canyon. These notches give the cliffs a striking resemblance to a series of great rounded gables in alignment (figure 11). The slopes of these tributary gorges are graded and covered with sage and grass. Rock ledges in them are rare. ‘They clearly are the relics of a pre-Spokane - drainage line, the trunk valley of which was entered and greatly enlarged by the Spokane waters. Both widening and deepening in the basalt oc- curred and the tributaries were left hanging. They have since attained topographic adjustment by building large alluvial fans out on the canyon floor. Furthermore, Moses Coulee crosses the Badger Mountain fold, as already noted. Like the crossing of the Soap Lake anticline by Grand Coulee, this records an antecedent course determined long before the Spokane glaciation. | f Spokane waters could not have entered Moses Coulee if the parent ice- sheet had not pushed across or at least well up on the divide south of the 602 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU Columbia. Therefore, though no till or strie left by the Spokane ice are known on the south side of the Columbia west of Grand Coulee, the oper- ation of both Moses and Grand coulees proves that Cordilleran ice did cross the Columbia, and the Spokane features of Moses Coulee prove that it reached nearly as far south as it did in the later Wisconsin epoch. FicurE 11.—Cliffs of lower Moses Coulec The cliffs are 900 feet high. There are shown the pre-Spokane tributary valleys, the main canyon of Spokane age, and the post-Spokane talus. THE WISCONSIN GLACIATION The terminal moraine deposited by the Cordilleran ice-sheet in north- eastern Washington during the Wisconsin glaciation has been traced in part by Salisbury and student assistants.12 The ice reached the Colum- bia Plateau in two places. One of these was south of the capacious Okanogan River Valley, and the lobe which spread out on the plateau here reached 35 miles beyond the river and was nearly 50 miles wide. The other place was on the lower Spokane River and was of little conse- quence. The only noteworthy Wisconsin drainage derangement of the entire plateau was the reoccupation of Grand Coulee and lower Crab Creek. Through this route was poured the water from the Cordilleran ice-sheet along the entire front from the Rocky Mountains to the Okanogan lobe. Though the Spokane ice yielded much greater volumes of water, all told, than did the Wisconsin, it was carried by many valleys, no one of which ever contained the quantity which went through Grand Coulee during the later diversion. That flood was greater than the deep- 2 R. D. Salisbury : Glacial work in the western mountains in 1901. Jour. Geol., vol. DSO pps taba George Garrey: Glaciation between the Rockies and the Cascades, Master's thesis, in library of Department of Geology, University of Chicago. THE WISCONSIN GLACIATION 603 ened main channel of the Grand Coulee system could contain and all but one of the distributary canyons again were in operation. The level of the Hartline gravel plain was not reached, however, and Deadmans Draw remained untouched. The evidences for this conclusion are the character of the talus in Deadmans Draw, already outlined, and the gravel deposits in and at the mouth of Dry Coulee. These latter deserve a brief description. The gravel terraces of Crab Creek Valley above the junction of Dry Coulee, at Adrian, are fragmentary remnants in protected places and in general do not have sharp terrace forms. Most of the valley floor is at the floodplain level; but 3 or 4 miles east of Adrian the floodplain is ~ narrowed almost to obliteration by a great gravel fill whose surface is about 100 feet above the valley bottom. The creek here flows in a narrow inner valley, close to the southern wall of the rock-cut main valley. The surface of the gravel fill rises northward across the width of the main valley and continues up Dry Coulee, which in its lower part is likewise nearly filled. Though there is little difference in amount of weathering between this gravel deposit and the Spokane gravel in Crab Creek Valley east of Dry Coulee, it clearly is much younger in terms of erosion. Its dissection has just begun. It is traceable back up Dry Coulee to the three distributary canyons which lead southward out of the upper walls of Grand Coulee. In all probability it is a deposit made by the Wis- consin floods before the lower canyon of Grand Coulee was deepened sufficiently to take care of the entire discharge. Lower Grand Coulee therefore appears not to have been much deeper at the beginning of the Wisconsin discharge than the floor of these dis- tributary canyons. Grand Falls probably was formed during this epoch, taking origin at the head of Blue Lake, where the coulee begins its course in the tilted flows of the monoclinal flexure. This cataract has receded about 3 miles to that portion known as Dry Falls, west of Coulee City, and about 5 miles to the less pronounced falls at the head of Deep Lake, about a mile south of Coulee City. They could not have existed farther down the coulee, for there it is eroded on the strike of flows whose dip, on the average, is 45 degrees.?* Previous descriptions of the relation of the Okanogan lobe to Grand Coulee state that the ice-sheet deployed eastward only to the edge of the upper canyon; but the granite knobs in Grand Coulee above Steamboat tock are strongly glaciated down at least to the level of the present OQ. KE. Meinzer, in ““The glacial history of Columbia River in the Big Bend region” (Jour. Wash. Acad. Sciences, vol. 8, 1918, pp. 411-412), argues that the falls have receded for 17 miles, virtually the full length of the lower coulee. 604 J. H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA PLATEAU ageraded floor. The northwest sides of these hills are notably smoothed and rounded and some bear striz. ‘The orientation varies, as would be expected on rugged rock hills overridden by ice, but is not far from northwest-southeast. The southeast sides are steep and jagged. The sheeted structure of the granite apparently has lent itself to plucking by the ice. Furthermore, the summits of the basalt bluffs on the western side of the coulee also are striated in approximately the same directions, and striz and abundant large granite erratics are reported on the top of Steamboat Rock (figure 12). The glaciation of these granite hills and the basalt hill south of them occurred at the maximum deployment of the Wisconsin ice on the pla- teau. It can not be a record of the Spokane glaciation, for these granite Steamboat Rock FIGURE 12. Steamboat Rock is in the middle of the Grand Coulee and near the head. The talus is of post-Wisconsin age. hills then were buried hundreds of feet beneath basalt and have been exhumed by the erosion of both Spokane and Wisconsin glacial drainage. If it be argued that this exhumation occurred during the early stages of the Spokane glaciation, the ice later advancing into the head of Grand Coulee, the answer is that these exposed glaciated surfaces would have been obliterated during the interglacial interval. What became of the Wisconsin drainage when the Okanogan lobe crowded down into the head of Grand Coulee? Since the Spokane spill- ways to Palouse River are lower than all others on the plateau except Grand Coulee, and since there was an eastward route open to them in front of the Wisconsin ice, it might be expected that for a short time glacial drainage would be diverted to the Palouse. But reexamination of these spillways has found no signs of such occupation. Furthermore. THE WISCONSIN GLACIATION 605 the granite hills in the coulee close to the eastern wall do not show glacial smoothing, though all others do. This is interpreted to mean that the escaping waters kept a passage open along the eastern edge of the ice, which thus failed to close the coulee completely. All the water at this time flowed on the east side of Steamboat Rock, and perhaps the eastern wall of the canyon here was eroded back to expose the unglaciated granite hills and to make the greater width which the canyon possesses between Steamboat Rock and the Columbia.** ) A widespread submergence of the lower Columbia Valley is known to have occurred during the Wisconsin glaciation.** It is recorded by berg- floated erratic boulders, some of great size, scattered widely in the Co- lumbia Valley below the present altitude of about 1,250 feet above tide. The submergence was due to a lowering of the entire region relative to sealevel. The ponded waters rose sufficiently high to spread over consid- erable areas of the plateau, and glaciated boulders now are found where glacial ice or glacial streams could not possibly have transported them. Most of these boulders, and all of the large ones, are of granite. They are strikingly abundant in some parts of the Quincy basin, a distribution which points to Grand Coulee as the route by which they reached the basin. After one has seen the dozens of granite knobs in upper Grand Coulee, heavily glaciated on the northwest and apparently much plucked on the southeast, the conviction grows that most of these large granite fragments were quarried in the head of the coulee when the Okanogan lobe was at its maximum deployment. The ground moraine of the Okanogan lobe has but a small percentage of granite boulders compared with basalt boulders, and a still smaller percentage of large granites com- pared with large basalts. It appears, therefore, that some special condi- tion, such as that outlined above, must have existed to reverse the ratio among the berg-fioated boulders. The upper limit of these erratics earlier reported was 1,283 feet above tide, and in the eastern part of the Quincy basin none have since been found above that altitude; but on Babcock Ridge, near Trinidad, boulders of gneiss, granite, quartzite, schist, slate, and argillite have recently been found as high as 1,350 feet above tide.. On the hills northeast of Trin- idad a “nest” of twelve granite fragments from an inch to 16 inches in ciameter and one quartzite pebble have’ been found—all within a radius of 15 feet and at an altitude of 1,400 feet above tide. These seem clearly 14K. Oestreich (‘‘Die Grande Coulée,”’ Transcontinental Excursion of 1912, American Geographic Society, 1915, pp. 259-274) has suggested, and J. T. Pardee (‘‘Glaciation in the Cordilleran region.’’ Science, vol. 56, December 15, 1922, pp. 686-687) has asserted, that an ice-stream traversed Grand Coulee. J. H. Bretz: The late Pleistocene submergence in the Columbia Valley of Oregon and Washington. Jour. Geol., vol. 27, 1919, pp. 489-506. 606 J. H. BRETZ—GLACIAL DRAINAGE ©N COLUMBIA PLATEAU to have been carried here in floating ice. Hither the upper limit of the submergence was greater over the plateau than has been thought or there has been post-Wisconsin upwarping in the vicinity of Trinidad. The latter seems the more probable. Pardee has described a deposit of silt with sand and gravel, the Nes- pelem formation,’® in the Columbia Valley above Grand Coulee. This he believes to be of Wisconsin age and to have been caused by a lowering of the region such that the upper surface of the deposit (1,700 feet above tide) records the sealevel of that time. What is taken to be a part of this formation lies on the floor of Grand Coulee about Steamboat Rock and the granite hills. Its upper surface here is about 1,650 feet above tide and it is seasonally banded. From its position, it obviously was deposited after the margin of the Okanogan lobe and the diverted glacial Columbia had abandoned Grand Coulee. It therefore was deposited after the berg-borne debris had been carried through the coulee. None of this silt has been recognized in the Quincy Valley or in the Columbia Valley below the Okanogan lobe. It may be a record of the submergence, as are the berg-carried erratics. It also may be related to the ponding of the Columbia by the Okanogan lobe, or by the large Wisconsin Valley train from the Okanogan Valley, which Pardee describes and which was formed during the retreat of the Cordilleran ice-sheet. | Most of the fill of the Quincy structural basin, as shown by well records, is clay and silt. The Pleistocene boreal mollusks reported from the upper part of the clay** suggest that it was deposited while a glacial climate prevailed, but probably not when the glacial waters were being discharged across the northern rim of the plateau, for the gravels over- lying the clays were then carried into the basin. There appears to be one great summit plane of the gravels, now dis- sected into four parts. The altitude of the northern part of each terrace is about 1,250 feet above tide. The surface (restored) slopes toward the Frenchman Springs and Potholes cataracts on the western margin of the basin and toward the Drumheller plexus on the southern margin. A continuous grade exists westward into the bottoms of the eroded channels at the head of the cataracts, but to the south the gravel terrace is 150 feet above the floor of Crab Creek Valley immediately adjacent and as high as the basalt buttes among the channel heads. This gravel fill probably dates back to the Spokane epoch, though some of it may have been aggraded during the early part of the Wisconsin wy. T. Pardee: Geology and mineral deposits of the Colville Indian reservation, Washington. U.S. Geol. Survey, Bull. 677, 1918, pp. 28-29 and 47-50. 17 Schwenneson and Meinzer: Ground water in Quincy Valley, Washington. U. S. Geol. Survey, Water Supply Paper 425 E, 1918, pp. 143-144. THE WISCONSIN GLACIATION 607 diversion, as that at Adrian, where Crab Creek was completely blocked by Wisconsin gravel. ‘The basin fill is not dissected, however, as are Spokane gravel terraces in the upper Crab Creek drainage. This may be because it does not lie in a narrow valley and because it is very porous, absorbing all rainfall and allowing no surface streams to form. The dissection takes the form of three large meridional channels converging to the Drumheller plexus. Two of these lead from the mouth of Grand Coulee; the third and,easternmost leads from upper Crab Creek near the mouth of Dry Coulee. It seems probable that, though some interglacial trench- ing by Crab Creek occurred, these channels were eroded largely by the diverted Columbia during the Wisconsin epoch, the erosion being ren- dered possible because of the contemporaneous deepening of the two main Drumheller channels. The western channel is broad but much shallower than the other two. Its proportions indicate that it is the channel of a large stream, not the valley of a small one, and its shallowness indicates that it was abandoned early in the Wisconsin dissection of the fill. The mouth of Grand Coulee is an undrained depression containing Soap Lake. It is dammed by the gravel deposits in Quincy Valley. All drainage of the lower canyon of Grand Coulee comes to it, upper Crab Creek flows to it (when it flows at all), and the neighboring gravel plain, through an are of 180 degrees, from east through south to west, slopes back toward it. The slope in this arc is gentle and clearly constructional. Whether this back slope is wholly of Wisconsin age or dates in part from the Spokane epoch, it seems clear that it is a graded subfluvial slope, adjusted to the traction load and the velocity of a current emerging from Grand Coulee. The velocity here was greatest within the rock walls of Soap Lake and decreased rapidly as the waters spread out in the Quincy basin. The depth of that glacial stream can not be measured, however, by the difference in altitude of lake floor and gravel rim. Dur- ing the later stages of Wisconsin discharge, as the Drumheller channels were gashed more deeply and the three channels eroded across Quincy basin fill, notches appeared in the rim of the gravel barrier and the con- stricted portion containing Soap Lake probably was then deepened. In all gravels in glacial spillways across the Columbia plateau, basalt is by far the most important constituent. Only a small fraction of 1 per cent is of other material. It therefore is not to be considered as glacial outwash in the ordinary sense, for it has not come from the ~ Cordilleran glacial drift. It represents basalt eroded by the high-gra- dient glacial streams in producing scablands and canyoned coulees. Thus a brief episode in the latter half of the Pleistocene (the maxi- mum of the Spokane glaciation) introduced conditions under which the 608 J.H. BRETZ—GLACIAL DRAINAGE ON COLUMBIA. PLATEAU scablands, much more than a thousand square miles of the plateau, and more than a tenth of the total area of the plateau (as the term is used in this paper) have been denuded of overlying sedimentary deposits by running water. But, despite the enormous amount of erosion by escaping glacial waters in both Spokane and Wisconsin epochs, no permanent derangement of drainage lines, save that of the Palouse from Hooper to Snake River, resulted. The Palouse formerly flowed to Esquatzel Coulee by way of Washtucna Coulee. Its course to Snake River was shortened 50 miles by this diversion, probably during the Spokane epoch. The Wisconsin history of Drumheller channels and Moses Coulee has been outlined in the description of these features under “Spokane Glacia- tion.” It remains to note that the small amount of erosion in the syn- clinal plexus of Moses Coulee and the small valley train built by drainage from the tip of the Okanogan lobe suggest that this lobe may have evap- orated in considerable part. This suggestion of large evaporation may also explain the relatively small amount of Wisconsin water which came from the Cordilleran ice east of the Okanogan lobe. DIscUSSION Dr. ML. M. Lerguron: The speaker is to be congratulated on the char- acter of the work he has done in eastern Washington. A few years ago I had the opportunity to see some of the features which he describes, and the case for at least two glaciations is perfectly clear and, as he suggests, there may have been three. In support of this, I may say that in a gravel pit in the southwestern part of Spokane I found balls of apparently old glacial till in what seemed to be gravel of Spokane age. Mr. Oscar E. Mernzer: I was especially interested in this excellent paper, because of my own brief field work a few years ago in this region. The glacial features of the region are on a grand scale and very striking. I understand that in the Spokane Stage the lake in Quincy Valley dis- charged directly into the gorge of the Columbia and also through the outlet east of Frenchman Hills, and that the latter was over lava rock. How is the deep trenching of the plain in Quincy Valley during the Wisconsin Stage accounted for ? Author’s reply to Mr. Meinzer: Only the upper or gravelly part of the Quincy Valley fill is surely of Spokane age. Wisconsin waters added but little to this deposit. They eroded it instead, because of downcutting in the basalt at the Drumheller Channels at this time. All the remark- able features of that tract are in basalt and were produced largely by Wisconsin waters. Brief remarks were also made by Mr. Leverett, with reply by the author. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL 34, PP. 609-648, PLS. 5-12 SEPTEMBER 30, 1923 RANGE AND DISTRIBUTION OF CERTAIN TYPES OF CANADIAN PLEISTOCENE CONCRETIONS? BY E. M. KINDLE (Presented before the Society December 29, 1922 CONTENTS Page WO SD DS SSUES a Ee ce SOA ne peg aS ee ee Oe ea ear a 609 MMPS NAR OREE © COMCUECIOINS oC. sie e dint oie So aaa a cso: Wem eke wi nate AR ooo we eee 611 i eT INRR OTMET NIE eet Rests oh Sed SA! i'm Mca eles ks A aeee BOD ee dc age meal ladore Bg ets 614 ee ae ISERIES Tee ANIL eee ce cere fe cna eet ee tene cd os meen Sia RL RCD we 8 wine 617 eRe T EIN I) CORCPELIONS © <<. 0:5 acre Soa 45 Ha . a j Oo 8 i : ' a : ‘4 Zz eRe 4 < E iis be , a0 DQ. a a Mo | wow a z eae e) oa oe 1S) a a ea Criteria Used in Recognizing Active Faults. By wispien Taber___- e } 3 Pre-Cambrian Folding in North America. By William J. Miller_______ 67 4 pirdax to: Volume S322) eet a ae a ie Rr is of Florida Avenue and Eckington Place, Washington, D. C.) = i ‘non-receipt of the preceding part of the Bulletin must be sent to the ‘Secretary — eg _ order to Be: filled gratis. oe vl pale . hee Entered as second-class matter in the Post-Office at Washington, D. C., aie ry The Lake Superior Geosyncline. By W. O. Fietchkiss 20. eg — Geotherms of Lake Superior Copper Country. By Alfred (on Lene 2) ee - ait Cambro-Ordovician Section Near Mount Robsos. British “Colurabia.“ By Lancaster D: Burlings2 2-272 2- cp TO Re, eae os oe eee ‘ BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA cc kbetition. $10 per year; with discount of 10 per pom to institutions and a libraries and to individuals residing elsewhere than in North America. Postage to foreign countries in the postal union, forty (40) cents extra. Communications should be addressed to The Geological Society of America, Prof. Charles P. Berkey, Secretary, Columbia University, New York City (or ¢ care NOTICE.—In accordance with the rules established by Council, claims” fares ‘of the Society within three months of the date of the receipt of this number in * agi P- — under the Act of Congress of July 16, 1894. “: Accepted for mailing at special rate of postage provided for in Section 1103, a? Act of October 3, 1917, authorized on July 8, 1918. i PRESS OF JUDD & DETWEILER, INC., WASHINGTON, D. C. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 649-660 DECEMBER 30, 1923 BOUDINAGE, AN UNUSUAL STRUCTURAL PHENOMENON? BY TERENCE T. QUIRKE (Presented in abstract before the Society December 29, 1922) CONTENTS Page See TI RP eee nS Ds ate ence ae kW is ee Trew dietakar shea a Reset lala tees 649 OMENS te oles? swinger Fee! sd tos le esPis Sales e's tetas GPE senate 650 eR Er ele CUA Ip Bic apctic le «Gaia tae Yo, bile atin var Gaeta epay pe Malas 6's lee eDs lee 6S. Pere nl: MOM-CLASCIG COMMPEFESSION: 02). aie bide», oie alse Weld 5 alate alee es wares ed 653 Papen EMNOL YS he POLE STOCKS 65 sone b\e os ened ants, 00,2 ote elie oo sabe gee ow elele'n wee 655 RE SePUreCOVery ir LOIGCU TOCKS. 0 .o..°s 2 sie sw's ce ode abelecs calneedes 655 rita RING Tats 1 te UNOVPECHT MRSC eas By oar ase coer nlate Sk vw Atoia¥ete 2 Mew kleod bu stele eleleie aca ep a @4 o's 656 eaeaeemernsnesenR se FOtNCeT (OPEN AE 22) goa Aa lee) ono = n= ea SyRe y cls = Pe os ae mie gunn tele & 656 PARALLEL FoLps Common parallel folds with horizontal axes die out upward and down- ward at a distance which is theoretically infinite. However, the curva- ture becomes almost zero at a distance about twenty times the radius of perfect curves, at the center of the structure. Thus a semicircular parallel fold 200 feet in diameter would die out at a depth of 2,000 feet. A fold of the same type, to persist for a depth of 10 miles, would require a diameter of one mile at the surface. This theoretical structure involves enormous shortening of the central line of the folds and a diminishing shortening of the flanks, until at the place where it dies out the shorten- ing becomes zero (figure 1). Such a feature would be a remarkable case of rotational strain 6f a type in nature unknown to the writer. Certain folds which die out in depth are described by Van Hise.’ None of the cases cited appears to be a case of parallel folds; uniformly, the folds are in highly metamorphic rock characterized by similar fold- ing. However, this structure is usually recognized as a probability and is commonly cited as an explanation of how folds die out at great depths. 1 Manuscript received by the Secretary of the Society. December 30, 1922. *C. R. Van Hise: U. S. Geol. Survey, 16th Annual Report, part 1, 1896, p. 601. XGLIINT--BunL. Grot. Soc. AmM., Von. 34, 1922 (649 ) 650 TT. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON This leads to the consideration of the possibility of a reversal of the position of shortening in a parallel fold. Whereas in the type parallel fold the center is shortened and the flanks remain unchanged, would it not be possible for the center to be unshort- ened and for the flanks to suffer rotational shortening both upward and downward? This would lead to a parallel fold growing more and more folded on opposite sides of the central plane, the degree of curvature again being a function of the radius. In any case, the extent of the feature must depend on the persistence of the homogeneous containing Parallel Folding which dies out above and Below ee i Maximum _shorfening is along central axis_ . FIGURE 1.—Theoretical Parallel Folding layer, without which such a feature would be impossible. Boudinage may provide such a case. THE BoupDINS During the early part of August, under the leading of Prof. Max Lohest, certain members of the International Geological Congress visited the region of Bastogne, in southeastern Belgium. There one has the opportunity to see, in the local quarries, a type of deformation wlrich is so rare as to be almost unknown in any other place. This is the develop- ment of “boudinage,” as it is called by Lohest (figures 2, 3, and 4). THE BOUDINS 651 The Coblencian rocks (Lower Devonian) are composed of quartzite and schist, the quartzite being in beds of from about a foot to about eight feet in thickness. The quartzite layers appear to have been compressed in the direction of their bedding, with the result that they have been thickened. The thickening has been distributed in such a way that the beds have been separated into a number of parts distinct from one an- other, the parts in cross-section looking like barrels, the ends of which are separated from neighboring barrels by veins of quartz. In places where quarrying operations have removed the schists from the quartzite, one is able to see that the barrel shapes extend into eylin- ders which look like enormous sausages strung out side by side, from FIGURE 2.—IJcealized Boudinages The figure a, b, c, d shows the shape of the rock before it became a boudin. «a Bb and e d show the maximum shortening. Shortening decreases to nothing at the axes. e e indicate quartz veins. which appearance this type of deformation gets its name of boudinage. The quartz vein separating each boudin from its neighbor is quite char- acteristic, and the width of spacing between veins is evidently a function of the width of the bed. The boudins approximate a circle in cross- section. In small beds the circle is small; in large beds the cirele is large. THE QUARTZ VEINS The quartz veins do not penetrate the schist above and below these bands of quartzite. They appear to be confined entirely to the beds of quartzite. It is thought by Lohest,* following Stainier, that these veins 3M. M. Lohest: Congrés Géologique International Livret Guide, Excursion A3, p. &. 652 1. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON were formed in the quartzite previous to deformation. However, in this there is not complete agreement. Indeed, there are reasons for believing that the quartz veins were filled after the formation of the boudins. The quartz veins in neighboring bands of quartzite are not in linear continuation. The size of veins is in relation to the thickness of the quartzite bands, being narrow in thin bands and wide in thick bands. They show no appearance of having been bent or ruptured after filling. They are typical fissure veins. The quartz veins appear to be thicker near the center of the boudins than at the edges. They seem to be lenticular, with their greatest thickness at the axis of the cylinders, ac- cording to the indication on the figures (figures 2 and 4). The quartz FIGURE 3.—Boudinage, Carriére de la Citadelle. Bastogne, Belgium veins commonly are not truly lenticular. In many cases the vein is split up into veinlets, but the total width of the veinlets along the central axis is generally greater than the width of the veins at the edge of the boudins. The position of these features in the major fold is in question, because the general structure of the Bastogne area has not yet been determined. At the Carriére de la Citadelle the axis of boudinage appears to be horizontal, but in another quarry, at Luzery, the boudins have a dip of 35 degrees southeastward. Lohest believes that they occur only on the summits of folds, and it may be that the case at Luzery is on a roll near the summit of the anticlinorium or at the top of an anticline plunging at an angle of 35 degrees. However, in this particular place the veins are vertical, not normal to THE QUARTZ VEINS 695 the dipping beds, which indicates that this is on the flank of the anti- cline, if we suppose the veins to follow ordinary fracture cleavage. Fur- thermore, in this place the veins are larger near the top than near the bottom of the boudins, and the arguments in regard to the central thick- ness of quartz veins do not hold. ELASTIC AND NON-ELASTIC COMPRESSION In general, the boudins appear to have been formed by lateral com- pression under enormous loading, so that the terrane has been neither ‘arched nor crumpled, but the competent beds have been compressed longitudinally into symmetrical folds of relatively small size. During this deformation the schistose rock conformed to the more competent ee YicurE 4.—Boudinage, Bastogne, Belgium Traced from photograph used in figure 3. Transverse lines are quartz veins. bands of quartzite, which arched both upward and downward into the less resistant phyllites. The natural conclusion is that after compression the quartzite yielded to tension, giving rise to cracks which were dis- tributed equally throughout. The yielding to tension was more closely spaced in the thin beds than in the thick beds. The actual openings appear to have been wider near the axes of the beds than near the edges. The edges of the boudins were folded the most. Apparently, the folded parts were straightened enough to take up the slack, but the central parts, being unshortened originally, had to supply means of expansion, and therefore cracked open instead. The central part might have been compressed during the arching of the other beds, and therefore had a certain amount of elastic recovery. §54 T. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON We may suppose, however, that the elastic hmit of the quartzite might have been passed and the pore spaces were crushed closed. In this case the reduction might well have been as high as 7 per cent. This com- pression would shorten a bed three feet thick by 21/5 inches. It should be noted that this compression is non-elastic and unrecoverable on relief of pressure. A certain amount of elastic compression must accompany compression so great that the pores are closed. Recovery of this would be possible on relief of pressure. After closing of the spaces the quartzite would have an elastic com- pressibility about equal to that of quartz. This is very small, being | about 2.7 * parts per million per atmosphere. Supposing the compression to have been equal in intensity to the pressure produced by rock overburden 10 miles deep, the compression of the quartzite would have been of the order of about one-third of an inch per linear yard (0.02 per cent). ‘Thus a quartzitic bed under great com- pression might be reduced 21/5 inches per yard non-elastically and one- third inch per yard elastically, resulting in a total shortening of 28/15 inches per yard. This shortening could be accommodated by the outside beds by arching. By experiment and measurement, it has been found that a yardstick shortened by bending 28/15 inches results in an arch equivalent in height to one-seventh of its original length or to one-fifth of its reduced length. This is an arch of the shape of the outside layer of the boudins drawn in figure 5. | Supposing the boudins to have been formed by lateral forces which resulted in elastic and non-elastic compression of the axial parts and ordinary folding of the outer layers, there would have been a linear shortening of 28/15 inches per yard, of which 21/5 inches could: not be recovered by expansion after relief of pressure. There would also be a thickening of the beds equal to nearly 10 inches in the widest part us : the outside layers, arching upward and downward. After relief of pressure the arches might straighten in part, but the central region has little recovery possible. If the arches lengthen again under vertical pressure or decrease of lateral support, the central part must crack open. These cracks would be greatest at the center, where arching has been zero and where non-elastic compression has been a maximum. The cracks would have a maximum width of 21/5 inches 4+Trskine D. Williamson: Changes of the physical properties of materials with pres- sure. Geophysical Laboratory, Carnegie Institute of Washington, Paper no. 446, 1922, p. 506. ELASTIC RECOVERY OF FOLDED ROCKS 65d per yard, or 6.11 per cent. This is about equivalent to the size of the quartz veins between the boudins. Evastic RECOVERY OF FOLDED Rocks If we suppose, however, that the Coblencian rocks were so strong at the time of their deformation that the lateral forces were incompetent to cause the compression postulated above, we must discard the idea of change of volume of the axial material under compression. This does not eliminate, however, the possible effectiveness of the elasticity of the bent quartzite layers above and below the axial part of the boudins. On release of lateral pressure these arched layers would tend to spring back into their former shapes unless their deformation passed the elastic limit. The elastic limit of rocks is different for the tensional and for compres- sional strains, but the tensional elastic limit is the lower; consequently passing of the elastic mit will result in part failure of the arches by tensional cracks near the periphery. These cracks would be wide at the periphery and would decrease to zero at the axis. Veins of this type do not appear to prevail in the Carriére de la Citadelle, where the best observations are possible, although Lohest describes them as of that character. Surely, some of the veins are not wider near the periphery than at the axis. Most of them appear to be widest at the axis and to pinch out to nothing, both above and below, at the periphery. This latter type ap- pears to represent the cases of quartzite beds which were so deeply buried that under lateral compression they bent without rupture and without passing their elastic limit. On relief of lateral compression they tended to recover their former shape, thus increasing their geographical length by straightening their curves. Lengthening of the outer beds would make openings necessary in the unfolded material within. Thus, the width of the opening is inversely proportional to the longitudinal recovery. That which was bent the most could recover the most, and that which was unbent could rebound not at all. By the elastic straightening of the bowed beds, the unbent axial beds were pulled apart. The location of these planes of rupture would naturally fall between the boudins, where the opposing spring of neighboring arches would be concentrated. Large boudins would cause wide veins; little boudins would cause narrow veins. Such is the case. NoN-ELASTIC RECOVERY OF FOLDED Rocks In cases where the arches passed the elastic limit another explanation is necessary. ‘The arches were upheld against the weight of overlying 606 ==. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON sediments by lateral compression. After decrease of this lateral support the arches tried to flatten down again. However, this can only come about by lengthening of the boudin bed. This lengthening can be ac- commodated easily by the arched beds, but the unbent beds must fail by jointing in the necessity of keeping up with the lateral movement of the arched layers above and below them. The result is just the same as if the beds sprang back into their former shape by elastic recovery, to wit: cross-fractures which are wide at the axis and closed at the peripheries (figures 5 and 6). ForRMATION OF BOUDINAGE In the formation of boudinage we suppose something like the follow- ing course of events: first, the presence of very competent thin beds i} {ee QPeSoE oO —— Ae (oo t > <— Ee Sas ‘ T at ene emer a a ai a i A er —-s> —“LY at ers a4 Figure 5.—Formation of a Boudin by lat- FiGcurE 6.—Recovery, clastic or otherwise, eral Pressure—a rotational Strain of a Boudin, after Release of lateral Pressure inclosed in incompetent material; second, the concentration on these beds of compression great enough to thicken notably the incompetent members and to telescope the competent beds into boudins. Unless the overburden were large and highly competent, the boudin member would simply arch upward. However, it arched both upward and downward to an equal degree. PECULIARITIES OF BOUDINAGE There are no ordinary structures or portions in ordinary folds where these boudins can be formed. They are symmetrical about a vertical axis and about a horizontal axis; therefore they can not be formed on the flanks of folds. The axis of a fold might give place to one boudin in a bed, but not to a string of them. A series of drag folds might give PECULIARITIES OF BOUDINAGE 657 rise to something like them, if cross-veins should separate them similarly. But drag folds and boudins differ essentially in their axial parts. A drag fold is folded from top to bottom; a boudin is unfolded along its axis. Drag folds affect incompetent layers between competent beds; boudins occupy competent beds between incompetent layers. Drag folds are due to shear; boudins appear to be due to extreme rotational strain symmetrical about a horizontal axial plane (figures 7 and 8). The boudins look somewhat like the structures called phacoidal struc- tures by the British geologists. They report the case of an epidiorite dike wrenched into a series of isolated lenticles or “phacoidal” masses imbedded in a zone of reconstructed granulitic gneiss. The case is cited Compete nt Incompetent ; Qe Competent SunEEeneeeen <—_____— FiIGcuRE 7.—Boudin-like Features due to Drag-folding and Cross-fractures of a thin basic dike, disrupted and severed into seven detached lenticles of hornblende-schist, from 30 to 130 yards in length, all arranged parallel to the thrust and to the foliation planes of the reconstructed micaceous eneiss by which they are surrounded.’ Similarly pegmatites intruding hornblende-schists and biotite-gneisses have been broken and sheared into the same sort of forms.® Very small lenticles of from 3 to 6 inches long have resulted from the thrust-plane passing above a limestone formation there brecciated for a depth of 15 inches beneath the fault-plane,’ and Leith® cites the case of a porphyry of the Vermilion district of Minne- sota which, having been sheared into rhombs, was further metamorphosed into a pseudo-conglomerate containing elongated lenses like pebbles. All such structures are devoid of definite bedding which has any general relationship to the shape of the mass, whereas each boudin is 5B. N. Beach, John Horne, ‘and others: Geological Structure of the Northwest High- lands of Scotland, 1907. Memoirs of the Geol. Survey of Great Britain, p. 67. §Tdem, p. 263. 7™Idem, p. 504. §C. K. Leith: Structural Geology, 1913, p. 66. 658 1. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON composed of symmetrical arches, grading from those of a high curvature at the periphery to those of no curvature along the axial plane. Furthermore, the phacoidal structures are commonly surrounded by the enveloping layers of schistose rock wrapped about them. The boudins of a bed are side by side, unseparated except by quartz veins; never sepa- incempetent —_> <_——_ —_> < BSE Sic <— FIGURE 8.—Boudins rated by the schistose rock above and below them (figure 9). We must conclude that boudins differ from all other folds and structural features. Boudins must come as a result of some unusual type of deformation. Considering a series of boudin beds, we seem to recognize great shorten- ing in the incompetent layers and apparently no shortening along the axes of the boudin beds. This shortening of the incompetent beds must > {Com petent < 1NCempetent ee SE Echistose ae Solded Be : SA SS SSS Ss Se Schistese FIGURE 9.—Phacoidal Structure (on left) and Boudins bounded by schistose Rock (on right) The phacoidal structure is due to rupture of competent layers and abrasion of pieces by flow of schistose matrix. The boudins bounded by schistose rock are not broken nor rounded by movement of the matrix. result in thickening and uplift, and this uplift may approximate in shape that of a great boudin. Lohest maintains that the whole uplifted area of Bastogne is a giant boudin. If so, boudinage may offer an explanation of how some folds die out in depth, and how folds which increase in size with depth may pass out of existence at greater depth. In every case the boudins are separated from the overlying and underlying incompetent PECULIARITIHS OF PBOUDINAGE 659 material by shear zones. Similarly, a giant boudin may come to an end at considerable depth in contact with the deep zone of flow. If the central part of the boudins is not compressed as much as the outer arched beds, it is difficult to understand a great stratigraphic series of boudin beds, such as Lohest postulates at Bastogne. Such a series would represent alternating shortening and non-shortening of the in- competent and competent beds respectively—an almost incredible per- formance. Furthermore, a great boudin could have smaller boudins only in one row, along its central axis, which is not the case at Bastogne. And every boudin band would represent two great rotational strains swinging out from one another on opposite sides of the boudin axis, where both would be zero. Inversely, a series of parallel folds which die out above and below rep- resent two great rotational strains which swing in toward one another to a maximum at their union, starting from zero at distant points on oppo- site sides of the plane of their combination. Although the possibility of ordinary parallel folds, so persistent that they die out according to theory, is widely recognized, the writer knows of no case where the phenomenon can be proved in the field. It is almost certain that the most promising series of parallel folds grades into sim- ilar folds at relatively shallow depth. In like manner it is probable that the Bastogne uplift will ultimately be found to be much more compli- cated than a simple giant boudin, although the stratigraphic series of boudin beds almost proves that the quartzitic bands were shortened by ‘compression along their axes to a degree equal to their shortening by arching, and the boudinage is not really the structural opposite of parallel folding, but merely a very unusual type of shortening of a composite member, constituent parts of which adjust themselves to the compression by different mechanical methods. Nevertheless, the recognition of boudinage as a possible type of major folding, as well as a proved type of minor structure, may lead to happy results, and it may be helpful in explaining how deeply buried folds of large curvature may come to an end almost abruptly in contact with an incomplete zone of flow. The boudinage of Bastogne and vicinity provides a case of a rare geo- logical phenomenon. ‘There is no mention of this type of deformation in any works in English, so far as the writer is aware, nor does it seem to have had consideration from any but the geologists of Belgium. There are so many geologists in America who are carrying on or planning to undertake experiments which may throw light on the cause and mechan- 660 = T. T. QUIRKE—BOUDINAGE, AN UNUSUAL PHENOMENON ics of the deformation of the earth’s crust that it is desirable that every type of structure should be made familiar to all who are interested. One of the purposes of International Congresses is to offer to the geologists of the world a convenient opportunity of visiting the pecuhar or other- wise noteworthy phenomena of the country which is acting as host. Boudinage is one of those things, visited during the International Con- egress of 1922, which geologists may see in Belgium, although probably not known anywhere else in the world. In spite of the rarity of boudi- nages, they illustrate what a part of the earth’s crust has done under particular circumstances and what other parts are hkely to do under similar conditions, and their occurrence serves to point a warning to those undertaking mechanical experiments in structural geology. They em- phasize the oft-repeated reminder that the earth’s crust is not a uniform member, nor rigid, and that it is in no sense susceptible to theoretical treatment as though it were a member of uniform material and simple structure. There seems to be nothing in the arts or in nature which can be com- pared in mechanical origin to boudinages, which makes them the more interesting and the more worthy of study. It is hoped that we shall learn more about them through the researches of our Belgian colleagues. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 661-668 DECEMBER 380, 1923 SOME CRITERIA USED IN RECOGNIZING ACTIVE FAULTS * BY STEPHEN TABER (Presented before the Society December 29, 1922) CONTENTS Page WRI TNO ee NSE eee P at es Sach oa soe Aload SOSda Gath tis euwcs se anwiabacd As Pcl 8 ees wld whe 661 Srireniawised i recognize achive Faults... cs ck es oe eee sees eee 661 Phyvcmerdapnie evidence of recent faulting. . 0. 0... ck ce et we wee 662 Origin of small fault troughs found along active faults................. 666 INTRODUCTION A fault, once formed, long remains a plane of weakness, and stresses developing in the adjacent region are more likely to be relieved by adjust- ments along it than by the formation of new faults. This is especially true of faults that persist for long distances. The identification of active faults is of importance, since they are the loci of earthquakes, each new displacement of a growing fault resulting in an earthquake. CRITERIA USED IN RECOGNIZING ACTIVE FAULTS The criteria that have been used in recognizing active faults are: (1) the recurrence of earthquakes along faults, and (2) physiographic and geologic evidence of recent displacement; but each of these may be mis- leading unless the general stability of the entire circumjacent region be taken into consideration. . The Charleston earthquake of 1886 was one of the greatest recorded in North America, and aftershocks have continued in its epicentral area down to the present day, yet there is no physiographic or geologic evi- dence that crustal movements are going on more rapidly there than else- where in the Atlantic Coastal Plain. Therefore, disastrous earthquakes are no more to be expected in South Carolina than in other States of equal stability, such as Florida or New Jersey. * Manuscript received by the Secretary of the Society January 14, 1923. (661) 662 Ss. TABER—-SOME CRITERIA USED IN RECOGNIZING FAULTS In regions where crustal movements are now going on with relative rapidity, as on the Pacific coast, faults showing evidence of recent dis- placement may be classed as active faults, and along them renewed ad- justments may be expected to occur from time to time; but in regions that are relatively stable the probability of displacements in the near future is slight, even along recent faults, such as those of Mount Toby, Massachusetts.* » Estimates of the relative stability of most regions have to be based, at present, entirely on the magnitude of post-Pleistocene movements, and on the seismic history over a period of no more than a few centuries at most. Accordingly, accurate geodetic surveys should be made in the more mobile portions of the earth, at such intervals as may be necessary, in order to determine the character and rate of the crustal movements now going on. Such surveys would probably give a better indication of the stability of a region. | PHYSIOGRAPHIC EVIDENCE OF RECENT FAULTING Physiographic evidence is especially useful in locating active faults in regions where earthquake records are available for only a short time. Fresh fault-scarps, when present, indicate recent displacement, but scarps may be masked under thick deposits of unconsolidated sediments, and they are necessarily absent where the displacements are horizontal. Per- haps the most characteristic evidence is furnished by the presence of small depressions due to the downfaulting of narrow strips along the strike of the fault, for they seem to be equally prevalent along faults where the recent displacements have been horizontal and where they have been dominantly vertical. The fault forming the west front of the Wasatch Range is marked by a recent scarp having a maximum height of about 100 feet, which may be traced interruptedly for a distance of about 125 miles. The facts concerning the fault given in this paper have been abstracted partly from Gilbert’s monograph on Lake Bonneville? and partly from the field- notes of the present writer. In places the scarp splits up into two or more scarps, and where this branching is prominently developed narrow fault troughs and small undrained basins are prevalent. The exposed fault-planes dip toward the west at angles of 75 to 85 degrees. Striations on boulders in cemented Bonneville gravels as well as on the Carbonifer- 'F. B. Loomis: Postglacial faulting about Mount Toby, Massachusetts. Bull. Geol. soc. Am., vol. 32, 1921, pp: 75-80: *G. K. Gilbert: Lake Bonneville. U. S. Geol. Survey, Monograph I, 1890, pp. 340-357. PHYSIOGRAPHIC EVIDENCE OF RECENT FAULTING 663 ous limestone, where the two are in contact, prove that the recent dis- placement was chiefly vertical. The form of the scarps where they inter- sect narrow spurs is likewise indicative of the absence of an appreciable horizontal component parallel to the fault-plane. Variations in the height of the scarps where they cross certain post-Pleistocene features, such as alluvial fans, prove that in places, at least, the present height of the scarps is the result of more than one displacement. While no severe earthquakes seem to have occurred along the Wasatch fault since the region was settled, the evidence of relative instability in the surrounding region is such that the earthquake hazard must be rated higher than in the Mississippi Valley, which, because of the New Madrid earthquake and its aftershocks, has a less favorable seismic history. The faulting at the time of the Owens Valley earthquake of 1872 was accompanied by the formation of numerous depressed strips. The fault- scarps have been described by Gilbert? and Whitney,* and they are well illustrated in the maps and photographs by Johnson published by Hobbs.* The main scarp followed the base of the alluvial footslope of the Sierra Nevada for 40 miles, varying from 5 to 20 feet in height, and, where highest, it was paralleled by an opposite-facing, ten-foot scarp with a depressed strip between. Elsewhere the displacement was distributed over a belt of parallel, overlapping and sometimes branching faults, be- tween which the narrow strips were depressed from 2 to 10 feet. These strips varied in width up to 200 or 300 feet, and some were several hun- dred yards in length. One of the depressed tracts, several thousand acres in extent, is said to have moved northward about 15 feet. Some of the fault-scarps seem to have been formed in part at a somewhat earlier period. The San Andreas fault, extending through California for upward of 600 miles, is marked by hundreds of small depressions or sags, often holding water, and by long, narrow valleys. By means of these features the fault may be readily traced through most of its course. It is, in fact, characterized by valleys rather than by scarps. Some of the valleys are known to be diastrophic in origin, while others, such as the through valleys, are also probably due chiefly to faulting. Small trenchlike de- pressions were formed along the fault during the earthquake of 1906 and some of the preexisting and usually larger depressions were deepened. 7G. K. Gilbert: A theory of the earthquakes of the Great Basin; with a practical application. Am. Jour. Sci., 3d ser., vol. 27, 1884, pp. 49-53. *J. D. Whitney: The Owens Valley earthquake. Overland Monthly, vol. 9, 1872, pp. 130-140 and 266-278. °W. H. Hobbs: The earthquake of 1872 in the Owens Valley, California, Beitriigen _ Zur Geophysik, Bd. 10, 1910, pp. 352-384. 664 Ss. TABER—SOME CRITERIA USED IN RECOGNIZING FAULTS The displacement at that time extended for over 190 miles and was chiefly horizontal, amounting to a maximum of 21 feet. Vertical dis- placement, where present, was small, and the low scarps faced west in some places and east in others. Horizontal displacements along faults are scarcely mentioned in most text-books, and that along the San Andreas fault in 1906 has been re- garded as exceptional; but I believe that movements of this type have been prevalent along the northern half of the fault since the Pleistocene, and that such movements have probably played a very important part in the development of the fault. The evidence bearing on this question is outlined below. Along the northern half of the fault fresh scarps, other than those that inclose the narrow troughs, are few and inconspicuous, and yet the numerous troughs and sags furnish evidence of repeated displacements in.recent time. | The fault-plane seems to be approximately vertical. It is true that the fault, instead of being a single break, is a complex of parallel and branching fractures, but the width of the zone of fracturing is seldom more than a quarter of a mile, which is small as compared with the probable depth of the fault. The fault trace formed in 1906 was not deflected where it crossed surfaces sloping in different directions. Al- though large vertical displacements have resulted from past movements, especially along the southern portion of the fault, there is no continuous scarp on either side; a mountain block has been uplifted in one place to form a scarp facing southwest, while in another the scarp faces north- east. Between Tomales Bay and Bolinas Bay, Lawson found evidence of large movements at different times in opposite directions, so far as the vertical component was concerned.’ For long distances there is no important scarp, and at a number of places the rocks exposed on both sides of the fault are the same. ‘The fault crosses from one side of the Santa Cruz Mountains to the other, and in its long course it passes from the west side of the Coast Ranges to the east side. Tangential thrust at right angles to the fault could not produce a vertical fault-plane nor account for the alternating scarps. It is not. likely that the fault was the result of tension, for it maintains its long course, without deflection, across different kinds of rock and earlier structural features. It is not conceivable that a fault extending for such a distance with only minor deviations could originate from purely ver- ® A.C. Lawson and others: The California earthquake of April 18, 1906. Report of the State Earthquake Investigation Commission, Carnegie Inst. of Washington, Publica- tion INOt GS 7., vol tpt a tOOS wep. see: PHYSIOGRAPHIC EVIDENCE OF RECENT FAULTING 665 tical forces, especially since the uplift changes from side to side. If the fault was formed in none of the ways mentioned above, it must have Scale of Miles { ra) 2 | TS EE ee eee Merced Lake ie OOSIONYVYAYYS NVS AWA yy > f za oO Oo O m > 2 \ San Andreas L. AW rystal Springs Lake \ F1iGURE 1.—Principal Faults on the San Francisco Peninsula After A. C. Lawson, with additions by Stephen Taber originated through shearing in a horizontal direction; and, once formed, local stresses due to uplift of adjacent areas would be relieved by vertical adjustments along it. XLIV—BuLL. Grou. Soc. AM., Vou, 34, 1922 666 Ss. TABER——SOME CRITERIA USED IN RECOGNIZING FAULTS The branch faults that leave the main San Andreas fault on the San Francisco Peninsula, such as the Black Mountain fault, the San Mateo Creek fault, and a fault located by the writer, which extends from the western branch of San Andreas Lake and reaches the coast a half mile south of Mussel Rock (see figure 1), are all readily explained on the hypothesis of horizontal shear. Branch faults of this type are not a characteristic of normal faulting or of reverse faulting. ‘The numerous small ponds between Mussel Rock and San Andreas Lake indicate that there are several other branch faults in that section. Several displacements are known to have occurred along the San Andreas fault since the settlement of California, though in most in- stances the direction of movement is unknown. Vertical displacements, however, are much more likely to be recognized and reported than hori- zontal ones, especially in thinly settled regions, and the scarps formed are conspicuous for years. In 1857 the southern half of the fault was ruptured, but the direction of displacement was not recorded. In 1890 a rupture is said to have occurred near San Juan, with a small displace- ment in the same direction as in 1906. During the earthquake of 1901 a crack was formed along the fault in the Cholame Valley which could be traced for several miles.? The earthquake of January 31, 1922, which originated under the Pacific Ocean about 300 miles off the Oregon coast and approximately in line with the San Andreas fault, was felt much farther from the origin than the earthquake of 1906. It likewise was probably caused by a hori- zontal displacement along the San Andreas or some parallel fault; for, as there was no sea wave, there could have been no appreciable vertical movement of the sea-floor. While it is outside the scope of the present paper, I wish to point out that the forces necessary to produce the displacements now in progress along the San Andreas fault must be regional and not local, and that there are other faults parallel to the San Andreas fault, such as the Hay- wards fault, on the opposite side of San Francisco Bay, which show the same physiographic characteristics. ORIGIN OF SMALL FauLtT TROUGHS ALONG ACTIVE FAULTS Several hypotheses have been advanced to explain the formation of the small fault troughs and depressions formed during earthquakes. _ Fuller suggests that those formed at the time of the New Madrid earth- quake were due to undermining caused by the creep of quicksand into “A, C. Lawson and others: Op. cit., pp. 38 and 40, ORIGIN OF SMALL FAULT TROUGHS ALONG ACTIVE FAULTS 667 rivers. This might account for circular and more or less irregular- shaped depressions, but hardly for rectilinear trenches with such sharp steep sides and flat bottoms that they suggest canal excavations. The hypothesis is certainly inapplicable to the depressions mentioned in the present paper. Gilbert, in explaining troughs at the base of the Wasatch scarp, as- sumed that the fault-plane separating the alluvium from the firm rock of the mountain had a dip of 60 degrees, and that the recent uplift of the mountain block relative to the alluvium resulted in a break which, as it approached the surface, curved upward away from the fault-plane so as to leave a triangular prism of alluvium attached to the rock consti- tuting the footwall. The open fissure formed by faulting along the up- curving surface would be immediately filled by the settling of one or both walls.° ; The objections to this hypothesis are: (1) that depressions are absent for long distances where there is a single fault-scarp instead of several branching fractures and there is no other evidence of open fissures having been formed; (2) that pressure effects, such as striations, are found along the fault surface in gravel cemented by calcite as well as on the solid rock; (3) that at the only place where the fault-plane was observed in solid rock the dip was as steep or steeper than in the alluvium and glacial drift; and (4) that it is not applicable to similar troughs along the San Andreas fault where the displacement was horizontal, or to those formed in solid rock during the earthquake at Yakutat Bay, Alaska."° Later, Gilbert explained the sags and ridges along the San Andreas fault in the Bolinas-Tomales Valley as due to “the unequal settling of small crust blocks along a magnified shear zone,” + but he advanced no theory to explain the settling. The horizontal displacement of 1906 was accompanied in places by slickensides and similar evidence indicative of compression normal to the fault rather than of tension. Oldham attributed the formation of certain depressions during the Assam earthquake of 1897 to the lurching of alluvium at the base of hill slopes, but such depressions follow the windings of the contact between hill and plain.?? 8M. L. Fuller: The New Madrid earthquake. U. S. Geol. Survey, Bull. 494, 1912, pp. 48-58. °G. K. Gilbert: Lake Bonneville. U. S. Geol. Survey, Monograph I, 1890, pp. 355-356. OR. S. Tarr and L. Martin: The earthquakes at Yakutat Bay, Alaska, in September, 1899. U.S. Geol. Survey, Prof. Paper 69, 1912, p. 37, and plate XVII, C. 4G. K. Gilbert: “Characteristics of the rift’ in the California earthquake of April te i0G; vol. i, pt, 1, 1908, pp: 33-84. #”R. D. Oldham: Report on the great earthquake of 12th June, 1897. Mem. Geol. Survey India, vol. 29, 1899, pp. 92-93. 668 Ss. TABER—-SOME CRITERIA USED IN RECOGNIZING FAULTS Troughlike depressions and undrained basins may be formed on slop- ing surfaces by a warping or selective uplift of the lower side of a fault, but in most cases the uplift is on the opposite side and therefore tends to accentuate the slope. A careful study of the small fault troughs and other depressions found along several active faults has led the writer to the conclusion that most of them are due to the downthrow of narrow blocks or wedges within a belt of parallel and interlacing fractures. The settling of the blocks is believed to take place while the rocks are momentarily separated by the passage of earthquake vibrations. The formation of these small troughs and sags is, therefore, regarded as a result of earthquakes and not as a cause, though it is probable that some aftershocks are due to minor dis- placements of blocks which have not reached a position of complete stability during the earthquakes. During the California earthquake of 1906 a fault fissure was opened so wide as to admit a cow, which fell in head first and was thus entombed, the closure leaving only the tail visible. At this point a trench was formed 6 to 8 feet wide and 1 or 2 feet in depth.?* When a small fault trough is formed in rock that is buried angen thick deposits of unconsolidated sediments, the surface manifestations may be no more than a shallow depression without definite boundaries. It was largely by means of such depressions that the writer traced the Inglewood fault of southern California.** Ridges are sometimes left between two downfaulted blocks, but most of the low ridges formed during the California earthquake of 1906 were due to the breaking up of surface soil into a loose aggregate of irregular clods or blocks, with a consequent high percentage of voids, and they gradually disappeared as the material again became compacted. The hypothesis advocated above is not applicable to large fault troughs having a width of several miles, which seem to be formed as a result of repeated displacements, sometimes on one side and sometimes on the other. ‘The displacements which result in the formation and growth of large fault troughs are, therefore, regarded as a cause of earthquakes and not as effects. %G. K. Gilbert: “The earth movement on the fault of April 18, 1906—-Tomales Bay to Bolinas Lagoon,” in the California earthquake of April 18, 1906, vol. 1, pt. 1, 1908, Ds 2: * Stephen Taber: The Inglewood earthquake in southern California, June 21, 1920. Bull. Seis. Soc. Amer., vol. 10, 1920, pp. 139-142. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP.669-678 DECEMBER 30, 1923 THE LAKE SUPERIOR GEOSYNCLINE?. BY W. 0. HOTCHKISS (Presented before the Society of Economic Geologists Dec. 29, 1922) CONTENTS Page Pea pa MIME [HEC ING doy cue Tah de yee tees wd na, OLS ne An A tr I il ak rae oe ee 669 Pea ens MIClhiIded) 1M) TE ~SVTUCUME css a! 6 ai see dee sb chess wis pels wv wee oe 3 ate 670 Directions of slopes on which sediments and flows were deposited....... 670 Pametecs or cutine Of, the land SUETACES «0.6.66 ec cc ce eck. oc se eeaaees 672 Paneioshacic tO We) imbued. Into The StOLy o.. . 00...) ds eas sein oc oe cee dase 673 Bapopiesis explaining the foregoing factS....... 0.05.00 5s cee cee accees 673 “Sp ELD ISS SUP Es CVETO eR are Sena Rae ed Se am nO a 673 Pie Mesa Ae Ol 1s Data y LUM ok o.0 eedsl edie gue see ctuleta sce sew dese odes 674 imse ot the, bathylith and its CONSEQUENCES... ce. s ewe eee we eee 674 INTRODUCTION The rocks surrounding the western half of Lake Superior dip to the southeast in Minnesota and northern Douglas County, Wisconsin, and dip more steeply northwestward in the hmb extending southwestward from Keweenaw Point to Minnesota. As the main axis is not far north- west of the outcrop of the south limb, the syncline is not symmetrical. Dips of 25 to 30 degrees are unusually high on the north limb; on the south limb dips vary from 30 to 90 degrees. The purpose of this paper is to discuss briefly the major facts as they are now revealed to us in the rocks of this syncline and to construct a. hypothesis correlating these major facts in its history. This hypothesis relates the origin of the various formations and their present structure to the intrusion of an enormous bathylith, whose final result is evident to us in the scores of thousands of cubic miles of Keweenawan lavas and intrusives. ‘The gradual foundering of the roof of this bathylith is be- lieved to offer the most plausible explanation of the origin of the present structure. * Manuscript received by the Secretary of the Society April 19, 1923. . (669) 670 w. 0. HOTCHKISS—THE LAKE SUPERIOR GEOSYNCLINE Ja. 125-3 HORSEATIONS INCLUDED EN (PHIS SYNCLINE = ee The oldest rocks in this syncline are the Keewatin greenstones and Laurentian granites. These had undergone much deformation and metamorphism and were base-levelled before Huronian time. On this plain were deposited the Huronian sediments of the Mesabi and Gogebic districts. The rocks of these two districts are so much alike that only those in the Gogebic are described. On the Archean basement is first a Lower Huronian dolomite, present in the Gogebic but lacking in the Mesabi. Remnants only are left of this. Next follows the Palms quartz slate, which has a fairly uniform thickness of 500 feet over most of the range, but thickens rapidly at the east end to about 1,000 feet. This is a greenish gray, unoxidized formation. The Palms is succeeded by the Ironwood formation. This is about 500 feet thick at the west and thickens gradually to about 1,150 feet at the east end of the range. The same beds which make up the 500-foot section on the west are 900 feet thick in the east. The top of this forma- tion has certainly been eroded, but the differences in thickness are probably due more to original deposition than to erosion. The Ironwood is succeeded by the Tyler formation—a great unoxi- dized, greenish gray slate and graywacke series with much iron carbonate near the base. It reaches a thickness of 214 miles a short distance west of the Michigan-Wisconsin line and tapers to nothing 20 miles to the east and west. Here again the top of the formation is eroded, but how much the varying thickness is due to erosion and how much to original deposition can not be stated with certainty. Again both factors probably enter into the complete story. The Tyler is followed by the Lower Keweenawan sandstone or quartzite and conglomerate. This formation is poorly exposed and probably is not always present. Its thickness is less than 100 feet, as a rule. It is chiefly a brown to yellowish oxidized formation. When pebbles are present, they are predominantly of quartz porphyry. Then follow the Middle Keweenawan basic flows and intrusives, with occasional quartz porphyry flows and intrusives, and acid conglomerate and quartz sand beds. This series varies in thickness from 3 miles to 6 miles. ‘ DIRECTIONS OF SLOPES ON WHICH SEDIMENTS AND FLOWS WERE DEPOSITED The direction of the original slope of the Archean baselevel is not known. DIRECTIONS OF SLOPES 671 The Palms quartz slate is a shallow-water deposit with ripple-marks nearly parallel to the present strike, but pitching down to the east a few degrees. These ripples have been interpreted as possibly being parallel to the shore. Which way this shore lay—to the north or south—is not indicated. Its uniform thickness over most of its area and rapid thicken- ing at the east indicates a bottom that was level and sinking at a uniform rate except at the east end, where the sinking was more rapid. The Ironwood formation, by its parallelism to the Palms, indicates a continuation of Palms conditions as to slope of bottom, with probably a more general tilting to the east indicated by the gradual thickening of the formation in that direction. The Tyler slate (and graywacke) was preceded by some erosion, but wherever observable its lower beds are essentially parallel to the Iron- wood. Its character indicates a gradual sinking of the bottom and a fairly rapid accumulation of the sediment in relatively shallow water. Whether its thick middle and thin ends are due to more rapid sinking of the middle and consequent thicker deposition or to deposition of a uniform thickness and later erosion is not known, but it is probably due to both. At any rate, the general axis of the basin must have been nearly parallel to the present outcrop. The shore may have been either to the north or south so far as evidence from the formation is known. The Lower Keweenawan sediments have not been studied sufficiently to be sure from which direction they came. Such evidence as we have is slight and conflicting in character. The flows give much better evidence with few conflicting features. In a quarry in the base of the flows north of Ironwood the second flow advanced over a thin mud deposit and squeezed it up before it in such a manner as to indicate that the flow advanced from a northerly direction. A second line of evidence is the fanning of the dips. The flows at the south are much steeper than those at the north in practically every known section. This can be explained as the normal decrease in dip of the beds toward the middle of a normal compression syncline. It can equally well be taken as an indication of flows thickening away from the source to fill a sinking syncline, but this implies a source outside the syncline for which good evidence is lacking. It is believed that the flows thinned away from the source in normal fashion and that this thinning up the present dip indicates a source now concealed down the dip. A third line of evidence for the direction of movement of the flows was seen with Graton and Butler and their associates this past summer in the Calumet and Hecla mine. Here the bottom of the flow that cov- ered the Calumet and Hecla conglomerate showed a great number of 672 w. 9. HOTCHKISS—THE LAKE SUPERIOR GEOSYNCLINE long-drawn-out “pipe” amygdules nearly perpendicular to the base of the flow. These were believed to be due to steam produced by water present in the conglomerate. The tops of these pipe amygdules were uniformly bent up the dip, indicating that just before solidifying the lava was moving upward in relation to the present dip, or, in other words, that the slope on which it flowed was down to the south and east. One case of cross-bedded sand in the base of the conglomerate was called to my attention by Doctor Lane. This showed that the depositing water current at that pomt was flowing in the same general direction—down- ward to the southeast. Though it may not be held that the evidence is conclusive that the original Keweenawan slopes in the Gogebic district were all downward to the south and east, nevertheless what evidence is available is practi- cally all in agreement with this conclusion and justifies as a working hypothesis the assumption that the source of the flows was in the present bottom of the syncline. Further evidence is needed, and, whatever its character, will doubtless be forthcoming in future geologic work on these formations. EVIDENCES OF TILTING OF THE LAND SURFACES A cross-section from the Archean baselevel to the Upper Keweenawan sandstones through Bessemer was made by Gordon for the Michigan Geological Survey and published in 1906. This is typical for the whole range and shows the Ironwood dipping north 60 degrees, the lowest Keweenawan flow dipping north abcut 80 degrees, and a gradual lower- ing of the dip to 30 degrees in the outermost flows. If we accept as a working hypothesis that the flows were poured out on a south-sloping surface from a source to the north of the present out- crop, then the iron formation must have been tilted at the time of the first flow so that it had a southward dip of 20 to 30 degrees. This indi- cates a rising of the land to the north, which had apparently been progressing all through the deposition of the Tyler, as we find the north- ern outcrops of that formation often dipping more steeply than the iron formation and the basal beds of the Tyler. If the source of the flows continued to be the same—north of the pres- ent outcrop—then the greater elevation of the surface to the north must have been maintained continuously throughout the accumulation of the flow series. The surface of each succeeding flow must then have marked a gentle southward slope at the time of its outpouring. This being the case, the decrease in present dip of the upper flows as compared to the lower must indicate a gradual tilting of the lower flows and the Huronian EVIDENCES OF TILTING 673 beds as the flow series was accumulated. The Huronian iron formation, which dipped south 20 to 30 degrees at the time of the first flow, was, if the above interpretation is correct, gradually tilted back so that it had a horizontal position when the flow series had attained a thickness of about 2 miles, for flows that far up in the series are parallel to the iron forma- tion. The tilting continued so that when the uppermost flow was ex- truded on the south-sloping surface the lowermost flow dipped about 50 degrees to the north. The tilting continued during the deposition of the Upper Keweenawan sandstones. OTHER FACTS TO BE FITTED INTO THE STORY Numerous dikes cut the Huronian and some of the lower Keweenawan flows. They evidently filled major joints in the main, for they have a general parallelism. In general, they pitch downward to the east about 15 degrees from the horizontal and dip about 45 degrees to the south. Thus their strike at the surface is now northeast where the iron forma- tion strikes east. In the lower part of the iron formation is a great bed fault which dis- places the dikes and the younger part of the formation upward and east- ward 800 to 900 feet in the westernmost mines and 500 feet in the region of Bessemer. _ A great gabbro laccolith extends from the Wisconsin-Michigan line westward for 50 miles. It maintains a thickness of 2 miles in its western part, and west of Mineral Lake bulges to a thickness of 4 miles. Field work in 1923 indicates that this is not a single-laccolite, but rather a series of parallel laccolitic intrusions into the lower part of the flow series. Another fact to fit into the story is the great abundance of acid sedi- ments interspersed between the flows. According to Lane, in the Besse- mer section the amount of these is much greater than the total mass of acid igneous rocks now visible, and also much greater in amount than the basic sediments. Acid conglomerates exist in Wisconsin directly associated with acid flows, and it is believed that the sediments represent partial erosion of such flows, which, however, did not get so far from the volcanic source as the sediments. HYPOTHESIS EXPLAINING THE FOREGOING Facts GENERAL STATEMENT The origin and structure of the rocks of the Lake Superior syneline fit in with the story of a great bathylith. It is my conception that this 674 w. 0. HOTCHKISS—THE LAKE SUPERIOR GEOSYNCLINE bathylith rose from great depths within the earth slowly and through long geologic periods; that it was rising during all Huronian time, and played an important part in determining the character and thickness of the Huronian deposits. This hypothesis is advanced to be criticized, to’ see whether it is possible to relate all the major facts as suggested in this paper or whether there are insuperable difficulties that may be brought forward. SIZE AND SHAPE OF THE BATHYLITH The size of the bathylith is indicated in part by the amount of material extruded. The main part of the trap-rock syncline—from near Minne- apolis to the end of Keweenaw Point—is 300 miles long. It averages about 80 miles in width. If the hypothesis here advanced is correct, the average thickness of igneous rock would be well over 4 miles. This indi- cates a total volume of the order of magnitude of 100,000 cubic miles— enough to cover the New England States and the State of New York with lava flows a mile in thickness. How much of the original magma solidified within the chamber in addition to that extruded we have no means of knowing. While this amount was probably large, it can be neglected in our present consideration. Assuming that the bathylith was elongated parallel to the axis of the present syncline and equal to it in length, we have a cross-sectional area of at least 320 square miles (4 X 80). While it is probable that the shape of the bathylith in cross- section varied greatly from time to time during its rise from the position of origin, it seems most probable that its vertical diameter was much greater than the horizontal. If the horizontal diameter was 8 miles, the vertical averaged 40 miles. Any pair of diameters can be selected to meet the reader’s ideas of what is most probable mechanically. RISE OF THE BATHYLITH AND ITS CONSEQUENCES The rise of the molten mass in the deeper portion of its travel must have been approximately lke that of a drop of oil rising in water—the material above it flowing very slowly to the sides and that adjacent to the lower part flowing in—a gravitative phenomenon, the molten mass rising because it was lighter than the surrounding rocks. If the molten rock were 2 per cent lighter than the surrounding solid rock (assuming a specific gravity of 3.00), the differential pressure on the top of the magma reservoir would be about 130 pounds per square inch for each mile of vertical diameter of the fluid mass. There would be a minimum vertical diameter of the fluid mass determined by the force with which the overlying solid rocks resisted being pushed aside. If the vertical HYPOTHESES EXPLAINING THE FACTS 675 dimension of the magma were too small, sufficient differential pressure would not be developed to force the superjacent rocks aside. As this dimension increased, the rate of rise would be more rapid. We know too little of the effect of differential pressure on rocks subjected to the tem- perature and pressure at great depths to know what pressure would be necessary to cause a magma to rise, so the best idea we can express is that the horizontal dimension of the fluid mass was probably much less than the vertical. | With this necessarily somewhat vague picture in mind—of the size and shape of the rising magma—let us start with the Archean baselevel, take up the various events in order, and point out how each might be, and possibly is, related to the great intruding mass. One of the early surface manifestations of the rise of such an extremely large mass of magma would be the elevation of the surface, the magma floating the surface rocks up. This might well occur long before any other surface evidence of a molten mass below. Assuming the position of the magma to be under the axis of the present syncline, a gentle doming of the Archean baselevel would take place, with resultant slopes down to the northwest and southeast, the long axis of the elevation being parallel to the present synclinal axis. This elevation would revive erosive processes and sediments would be deposited in the water-filled depressions on the flanks of the dome. ‘These depressions can well be imagined to be produced by the “undertow” of rock flowage—away at the top, down at the sides, and inward toward the bottom of the magma. These first sediments form the Huronian formations, chiefly the quartz slates, underlying the iron formation in the Mesabi and Gogebic iron districts. The inference from Palms ripple-marks that the shoreline extended in a northeastern direction fits with the tilting ascribed to the magma. The next major event is the deposition of the Mesabi and Gogebic iron formations. Van Hise and Leith, in Monograph LII of the United States Geological Survey, ascribe the origin of these formations to mag- matic water which contributed the iron and silica in solution to the water bodies in which the formations were deposited. In my own study of the Gogebic such a source seems to be the only one that offers an adequate explanation. ‘These silica-iron-bearing waters may be consid- ered to be the first surface contribution of the great mass of magma we are considering—a pre-volcanic emanation of vast volumes of solution that gave the first surface relief from pressure below. This relief might well result in a pause in the elevation of the surface and a more or less 676 W. O. HOTCHKISS—THE LAKE SUPERIOR GEOSYNCLINE complete cessation of clastic deposition while the nearly pure chert and iron oxide formation was being deposited. As the effect of this relief disappeared the eroded Archean rocks of the dome would again rise and a renewal of clastic deposition to the north and south of the dome would follow. These deposits are the Vir- ginia and Tyler formations of the Mesabi and Gogebic districts. Pro- gressive elevation of the dome and sinking of the trough during this deposition explains the changing dip angles of the Huronian beds which we find in the Gogebic district in going from the base to the top. At the close of this period the basal beds of the Huronian dipped 20 to 25 degrees south and the top was level. The next major event was elevation of the surface, probably more rapidly than at any previous time. The top of the Huronian rocks in © the Gogebic district was eroded and the eroded surface more or less com- pletely covered with a new type of deposit—a thin land deposit of quartz feldspar sand with pebbles of quartz porphyry, an oxidized yellow or red formation, very different from the green, unoxidized sediments beneath. This was quickly followed by a rapid outpouring of basic lavas. These last events are readily explainable by assuming that the magma was nearing the surface and about ready to break through. The rapid elevation and erosion at the close of Huronian deposition fits perfectly with this assumption. The source of the quartz-feldspar sands and porphyry pebbles can be found in the first extrusions of lava, which may well have been acid. Being more viscous, these would not flow far to the south and so might not be expected to be in evidence along the present outcrop. Later outpouring of the more fluid basic material would cover the Lower Keweenawan quartz-feldspar sands and porphyry conglomerate. Lane and Gordon? have estimated that the acid eruptives evident in the Black River section are about one-thirtieth as great in mass as the basic eruptives. On the other hand, the acid sediments derived from acid eruptives are about sixteen times as great in mass as the basic sedi- ments and about four times as great as the acid eruptives. This must indicate that close to the vents there were much greater volumes of acid eruptives than are exposed at the greater distances where the series is cut by the present surface. This is in accord with the common observa- tion that acid lavas are less fluid and tend to pile up relatively near the source. After the surface outpouring of lava began there were undoubtedly 2 Michigan Geol. Sury., Ann. Rept. 1906, p. 420. HYPOTHESES EXPLAINING THE FACTS 677 alternating periods of slow and rapid extrusion. Some portions of the main volcanic range would be quiescent while others were active. In any given part of the range there would be periods of activity and periods of quiescence. Dying the quiescent periods the magma beneath would have time for partial. differentiation. At the surface erosive agents would find time to spread acid conglomerate and sandstone beds over the flanks of the range, the material for which they found in the acid flows in the higher areas. When extrusion began afresh, the character of the flows would differ, more or less, from the preceding flows to corre- spond with the degree of differentiation that had taken place. This variation in character is strikingly brought out in Mr. Aldrich’s magnetic work in northern Wisconsin this past summer. During the time of the extrusion there was a slow progressive sinking of the range which nearly kept pace with the thickness of the extruded flows. This sinking was probably one of the chief causes of the con- tinuance of extrusion—the load sank into the magma reservoir and squeezed the magma out. This sinking affected the area for many miles on either side of the vents and included the Huronian rocks and the Archean rocks to the north and scuth. The ancient Archean baselevel in the Gogebic district was thus tilted back to a horizontal position, then northward, so its present dip is about 60 degrees to the north. _ After a moderate thickness of the lower basic flows had been extruded, numerous dikes found their way along tension cracks into the strike joints of the Huronian. At a later date these dikes were sheared by a great fault, an eastward and upward thrust of the upper part of the series parallel to the beds. Lane® has suggested that this may be corre- lated with the intrusion of the gabbro laccolith in Wisconsin. This in- trusion may also be contemporaneous with the development of the great Keweenaw thrust-fault, and the two upward thrusts of the north part of the series on the Gogebic may be a part of the same general readjustment. This could be accounted for mechanically as a gradual differential sink- ing of the outer rocks into the magma reservoir to force more lava out of the vents. These fault adjustments probably began when the north- ward dip of the lower flows was less steep than at present. At the time of the final extrusion there was most probably a high central range largely composed of acid flows. From this range was de- rived a goodly part of the Upper Keweenawan conglomerates, sandstones, and shales which have been estimated by Thwaites* to have a maximum thickness of nearly 25,000 feet. Soe: cit., p: 470. * Wisconsin Geol. and Nat. Hist. Surv., Bull. xxv. 678 Ww. 0. HOTCHKISS—THE LAKE SUPERIOR GEOSYNCLINE During the deposition of these sediments there was probably pro- gressive sinking due to the cooling and contracting of that part of the original magma that was not extruded. The cooling and solidifying of this mass would result in giving off large quantities, of solutions and gases, and the contraction would result in settlement and readjustment of the lava flows above it to make channels for the escape of the solutions. It is suggested that this igneous after-effect may be appealed to as the source of the copper mineralization which the members of the geological department of the Calumet and Hecla Mining Company have presented to us. After the deposition of the Upper Keweenawan sediments orogenic pressure from the southeast resulted in tilting the sediments and increas- ing the northward dip of the south limb of the syncline. This stress resulted in a great thrust-fault across northern Douglas County, in Wis- consin, which throws the middle or lower part of the flow series in contact with the youngest Upper Keweenawan sediments known. The succeeding history of the Lake Superior syncline has been one of gentle elevations and sinkings in all following geologic periods, in which the structure has not been altered, but has acted as a unit. The only modification has been that due to erosion, which has developed the surface as we see it today. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 679-702 : DECEMBER 30. 1923 PRE-CAMBRIAN FOLDING IN NORTH AMERICA? BY WILLIAM J. MILLER (Presented before the Society December 29, 1922) CONTENTS Page LETS SCTE GUCTIONG ics MS on TG Sree ta Vl ae Cae Cn oD ea a ane 679 eee Ma COMSTOErAGlOMS wip Sadie pani n c catesiiie’s oaeak ok EU bw outa ee Lees 681 Degree of folding of earlier pre-Cambrian rocks.:.................. 681 Post-Cambrian folding of pre-Cambrian rocks...................... 683 iuck-et records. for much: of the continent <2. 0.60. so. case teed es 686 Significance of the duration and subdivisions of the pre-Cambrian... 686 Observed strikes of pre-Cambrian folding and foliation................. 688 ESC Ma SEADEIMEN ae ect, Asse tte eee enaid. 5 lke a Reo Oe OO haute elo ade nea ees 688 iamrador,, Nova Scotia, and New Brunswick). .8 05. oc. be oie ye ees 689 UEISIGSIETAL: (CNIMaI CIE! Sah. See tsi Sie oc abt eI ga ee etn oLID SOAP TA al a Paes 689 LINEITEG | fh cone Coke SIR ee tee eae ae tne a a eae ee ee te 689 UTI ETERS chap at | ee et IAT i or A GG ay wt a 689 MY LSC EDL CNSY 5 Siem o tape A a a i OS ee a 690 MESSI (OR ITG OIE NSG ees eer ciclo este Cy een LE aN nn ek ne ee a 690 He SKM MOMGeUr SEALE Sire < sock Se hoe tbc aw wb hce Chaba ha eee edbeche 691 Poet e tal NIG” AOR Kas core aerate ota ads Ric eS S Siac eae oe cee bance e 691 ESVGARP «LUMEN OG | Sc wMes peRee SO ree eae see a ao an A oe a 691 EMO pA AcChtan-PICEMONE® TESION £05 ses bok re ee a ale ls bee bee 692 PMMMesOT eV ISCOMSiM. and) Michigan. <5... .6 bode elk eek eee ae es 692 Mise Ogle MGs SOUL MID AKOUM ac. circles. ane 64 os ahs k guste elo wie Wis We eels ea base 693 MRIS rmnM UE eta sy Pore Res areD, atthe ET otra) baa he cas Me na Ga ERIN a Mew gl Coomiieemla nei one! Baal acave e 693 Anizona, and New Mexico. .c.0. 56.60.08 eae Sos wen Sep) So Geer ae 694 RAVE EYE, POG EA DATE) apm oie ho lee e-em ele na pene a 694 CADICTED GLO: SE AEG a eeu See eG Blips Or em Rt SR ce he 695 “NY SOIC, US AOR er Ae RE Vee heey A ally oll ae al a er 696 orientale NGA epee enti SNe nm a0. etal elotseate stadedaiere a Nea ba Side so giete ¢ 697 Conclusions regarding the Cordilleran region...................... 697 SVU BIER CMGI ATSIOT ONS aaa es Poa a PER Ge a dc a a 698 “OOP SPUTISISG TT oy ks ARR ge Ri ee SRS aE POSE, Sch ac NAR hae any Unt ce 699 INTRODUCTION Any serious attempt to decipher the pre-Cambrian paleogeography of the continents, even if only in broad outline, should be commended. An 1 Manuscript received by the Secretary of the Society February 26, 1928. (679) 680 w.J. MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA elaborate effort of this kind has very recently been made? by R. Ruede- mann, whose paper is valuable mainly because of its highly suggestive features. In it he “ventures to suggest some possible fundamentals of pre-Cambrian paleogeography.” It is not too much to say that Ruede- mann has opened up a new and important field of geological inquiry. ’ 1 ‘ t ! ‘ ‘ ‘ ' ‘ ' 4 1 ! ‘ FIGURE 1.—Map of North America Showing, by the short, heavy lines, observed strikes of pre-Cambrian folding and foliation and, by the long, curved, dotted lines, the pre-Cambrian structural trend-lines advocated by Ruedemann. The short, broken lines indicate strikes of pre-Cambrian rocks developed mainly or wholly in post-Cambrian time. The present purpose is to confine attention to one very important aspect of the subject, in which the writer has been interested for some years, and this in its application to North America only. This aspect of the subject is the folding and foliation of pre-Cambrian age, with special 2R. Ruedemann: N. Y. State Museum Bulletin 240, 1922, pp. 67-152. GENERAL CONSIDERATIONS 681 reference to their trend-lines. This is a fundamental consideration in Ruedemann’s paper, and in his summary regarding the principal lines of pre-Cambrian folding in North. America he says: “The northeast of North America, including Greenland, exhibits a distinct northeast direction. . . . This northeast direction swings in the interior of the continent into an east-west line, and the latter turns into a north-south line as it approaches the Rocky Mountain region. The pre-Cambrian folding of North America exhibits thus a grand and simple curvature (see accom- panying map), which clearly proves this part of the earth to have acted as one unit against the diastrophic forces active in pre-Cambrian time.” Ruedemann’s conclusions regarding the trend of pre-Cambrian folds and foliation should not go unchallenged: for, as a glance at the accom- panying map shows, most of the actually observed strikes of pre-Cam- brian folds and foliation fall far short of warranting the representation of these structures in the form of “a grand and simple curvature.” Before proceeding to a discussion of observed strikes of pre-Cambrian structures, attention should be directed to certain important general con- siderations which must be constantly kept in mind in any attempt to deal with pre-Cambrian diastrophism. : GENERAL CONSIDERATIONS DEGREE OF FOLDING OF EARLIER PRE-CAMBRIAN ROCKS Most writers on the subject seem to take it for granted that the earlier pre-Cambrian rocks are everywhere severely folded and highly meta- morphosed. Ruedemann, for example, states (page 75) “that the Archean basement complex has undergone not only complete meta- morphism, but also a worldwide intense folding.” The present writer believes that the facts for certain (or possibly many) regions are op- posed to such a sweeping assertion. He pubhshed a rather elaborate paper® in 1916 in which, after critically examining the field facts and the views generally held, he concluded that the whole Adirondack area of earlier pre-Cambrian rocks, excepting the extreme northwestern side, has never been subjected to anything like severe orogenic pressure, and that the influence of the large-scale magmatic intrusives, accompanied by not more than very moderate lateral pressure, more satisfactorily explains the rock structures. The Adirondack Grenville (Archean) sedi- mentary series generally has its stratification remarkably preserved, and many large areas of the rock are either in nearly horizontal position or show only moderate tiltmg. Ruedemann states that these rocks have 3 Ww. J. Miller: Jour. Geol., vol. 24, 1916, pp. 587-612. XLV—BUuLL. Grou. Soc. AM., Vou. 34, 1922 682. w.J.MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA been highly compressed, and he mentions (page 76) a number of writers on the geology of northern New York in support of his contention. He might have added that a dozen years ago the present writer held the same view; but several of the writers mentioned have never professed to have seriously studied this problem, and several others give evidence only for the northwestern (Saint Lawrence Valley) side of the Adirondack region, which the present writer also believes does show evidence of more or less folding. For the ten thousand square miles of the Adirondack region proper, however, only two men, Cushing and Alling, have really argued for severe, even isoclinal folding, and they have largely ignored the array of evidence to the contrary, as set forth by the present writer in the paper above cited. Unless this array of evidence is seriously taken up and disproved, it is hardly fair to merely state without proof, as Ruedemann does, that the conclusion from that evidence is wrong. Ruedemann gives considerable attention to the pre-Cambrian of northern New York because it is a distinet, unusually studied area, in many ways “representative of the whole problem” of pre-Cambrian folding. Another area of earlier pre-Cambrian rocks which has been carefully studied is the Haliburton-Bancroft district,* covering over four thousand square miles of eastern Ontario, Canada. The region consists mainly of large, crude, oval-shaped granite batholiths protruding through Gren- ville (Archean) strata. These batholiths are arranged with a prevailing trend north 30 degrees east, and the strata usually lap over on them with quaquaversal dips, generally not at very high angles. A structure section across the region would not reveal a very highly folded arrangement of the rocks. It seems not at all unreasonable to interpret this moderate deformation as having resulted mainly from the upwelling of the batho- lithic magma bodies under conditions of not more than slight lateral pressure. Structure sections through both the Rainy Lake (Lawson, 1913) and Geneva-Sudbury (Tanton, 1913) districts of Ontario show that the older pre-Cambrian rocks are there considerably folded, but certainly not severely folded. In a number of studied areas of Ontario and Quebec, writers record rather persistently steep dips, while for other areas the degree of deformation is not stated in the publications. In a report on the “Selkirks and Interior Plateau of British Colum- bia,’ Daly? emphasizes the fact of the remarkable freedom of the Shuswap (pre-Beltian) series from deformation. 4H. D: Adams and A. E. Barlow: Geol, Sur. Can., Mem. 6, 1910. 5R, A. Daly: Geol. Sur, Can., Guide Book No. 8, 1913, p. 153. GENERAL CONSIDERATIONS 683 In a very recent paper,® dealing with the southernmost Rocky Moun- tains of Canada, MacKenzie says: “From the earliest pre-Cambrian known until at least the beginning of the Tertiary, the accumulation of sediments proceeded without interruption by pronounced deformation, varied from time to time by broad and relatively slight oscillations which caused local erosion and resulted in disconformities.” In the eastern Cordilleran district of the United States earlier pre- Cambrian rocks often show steep dips, but these rocks have usually been more or less intimately intruded by igneous material, which, in part at least, may have been the main cause of the steep dips. Throughout the Appalachian and western New England regions the pre-Cambrian rocks are more or less highly folded and associated with intrusives, and it is doubtful, as pointed out beyond, whether these rocks were subjected to more than very moderate compression prior to the severe Paleozoic deformation. From the above statements we may therefore conclude that various portions of the earlier pre-Cambrian rocks have been folded little, if any at all; that various portions have been only moderately folded; that vari- ous portions have been highly folded; and that still other portions are not proved to have been much folded in pre-Cambrian time. In many cases, even where steep dips are recorded, the writer believes that the deformation may reasonably be explained as a direct result of magmatic intrusion and injection, accompanied by not more than moderate com- pressive forces. Barrell,‘ who has advocated a similar explanation, says: “The gnarled and twisted rocks of the Archean speak of the presence be- neath them of molten magmas rather than of an enormous degree of com- pressive forces upon them.” For the reasons given, the writer can not subscribe to the statement that the earler known pre-Cambrian rocks were everywhere highly com- pressed and folded in pre-Cambrian time. POST-CAMBRIAN FOLDING OF PRE-CAMBRIAN ROCKS In any discussion of pre-Cambrian folding, discrimination must be made between those rocks which were folded in pre-Cambrian time and those which were folded in later time. In many cases this can be done, and often earlier and later pre-Cambrian deformations can be recognized. This is particularly true of many parts of the Canadian Shield. In other 6 J. D. MacKenzie: Transactions Royal Soc. Can., vol. 16, 1922, p. 98. 73. Barrell: Jour. Geol., vol.:238, 1915, p. 511. 684 w.J. MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA cases such distinctions have not as yet been very satisfactorily made out, as, for example, in the Appalachian-Piedmont region and western New England, where Paleozoic deformation has very largely overwhelmed and obscured whatever. pre-Cambrian folding there may have been. Struc- ture sections in various United States Geological Survey folios illistrat- ing the region from New Jersey to Georgia show both pre-Cambrian and Paleozoic rocks to have been folded in similar manner apparently by the same force or forces. Mr. Arthur Keith has, however, recently told the writer that there is evidence for at least some pre-Cambrian deformation. In the Nantahala, North Carolina, folio Keith says: “The various deformations (Precambrian and Paleozoic) have greatly changed the aspect of the rocks (Cambrian and pre-Cambrian)—so much so, in fact, that the original nature of some of the oldest formations can be at present only surmised.” Also: “Structures in the Archean uplift in the southeastern part of the quad- rangle do not differ radically from those in the sediments.” But in regard to the pre-Cambrian Carolina and Roan gneisses, he says that they have “passed through two deformations, one producing the foliation and a second folding the foliation planes.” Since these gneisses were originally probably either granites or injection gneisses, is it necessary to assume that their foliation was produced by severe com- pression? Could not this structure be either a primary foliation or a magmatic injection structure produced under conditions of only very moderate lateral pressure, according to the principles set forth in the writer’s paper® already referred to? Protessor Bascom in a recent letter says, in regard to southeastern Pennsylvania, that the “pre-Cambrian rocks were folded (in pre-Cambrian time), but I am not pre- pared to say ‘notably’; close folding can not be proven; there is general diver- gence of strike in some places over long distances; folding about igneous in- trusions of pre-Cambrian age can be positively differentiated from Paleozoic folding, of course relatively local in character. . . . Of course, the very intense Paleozoic folding now dominates and obscures all previous folding.” From these statements it seems reasonable to believe that such pre- Cambrian deformation as can be made out. may have been largely or wholly caused by the intrusives without severe compression of the region. 8 W. J. Miller: Jour.,Geol., vol. 24, 1916, pp. 600-612. GENERAL CONSIDERATIONS 685 For western New England the general situation seems to be somewhat similar to that of the Piedmont district. In both of these regions the pre-Cambrian rocks were much folded during Paleozoic time, but there seems to be little, if any, positive proof that they were very notably folded in pre-Cambrian time. In Wisconsin and Minnesota deformation of older pre-Cambrian rocks: may generally be distinguished from that of the younger pre-Cambrian, and almost undisturbed Cambrian strata rest on the pre-Cambrian. In the Rocky Mountain and Colorado Plateau districts of the western United States two sets of pre-Cambrian rocks, representing either one or two times of pre-Cambrian deformation, have been recognized in rela- tively few places, as, for example, in the Grand Canyon of Arizona; Needle Mountains, Engineer Mountain quadrangle, and Rocky Moun- tain Park, Colorado, and: Three Forks and Little Belt Mountains, Mon- tana. In a few districts, as, for example, Pueblo, Colorado, and Fort Benton, Montana, Archean pre-Cambrian rocks only are described. Al- gonkian rocks only are described as occurring in a number of districts, as, for example, Telluride, Rico, and Ouray, Colorado; Hartville, Wyo- ming, and Philipsburg, Montana. In most of the described regions, how- ever, the pre-Cambrian is not differentiated, as, for example, Georgetown, Silver Cliff, Pikes Peak, and Park Range, Colorado; Medicine Bow, En- eampment, Laramie-Sherman, and Bald Mountain-Dayton, Wyoming; Coeur d’Alene, Idaho; Bradshaw Mountains, Clifton, Globe, and Bisbee, Arizona, and Van Horn and Llano-Burnet, Texas. In most of the districts of the Rocky Mountain-Colorado ‘Plateau re- gion just mentioned the pre-Cambrian rocks, in part at least, are defi- nitely known to have been more or less deformed in pre-Cambrian time. In some of the districts the Algonkian strata are either not very notably folded, as, for example, Grand Canyon, Arizona, and near Marysville, Montana, or their folding was largely or wholly developed by post-Cam- brian disturbances, as, for example, Philipsburg and Three Forks, Mon- tana, and Ouray, Colorado. Hnough facts have now been presented to show that, in any attempt to work out the folded structures of pre-Cambrian age in North America, it must be recognized that by no means all pre-Cambrian rocks, and not even all the earlier ones, have been severely folded, and that a careful discrimination must be made between pre-Cambrian rocks folded in pre- Cambrian time and those folded later. Unless such a distinction can be made, the existing strikes of folds of pre-Cambrian rocks afford no trust- worthy criteria in regard to pre-Cambrian diastrophism. 886 w.J. MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA LACK OF RECORDS FOR MUCH OF THE CONTINENT Vast areas of North America contain few, if any, outcrops of definitely known pre-Cambrian rocks, as, for example, Alaska, Mexico, the Cor- dilleran region and plains of western Canada, the western Cordilleran region of the United States, the Great Plains, much of the Mississippi Valley, and the Atlantic and Gulf coastal plains. Even within the vast pre-Cambrian area of Canada observations on the rock structures are widely scattered, and there are hardly any for its northern half. Still another difficulty les in the fact that in many areas containing pre-Cambrian rocks descriptions of the rocks are very brief, and one often looks in vain for such structural data as the strike of folds and foliation. This lack of evidence in regard to so much of the continent is a very serious difficulty in the way of trying to determine any possible uni- formity or systematic arrangement of trend-lines or strikes of folding and fohation of pre-Cambrian age, the more so because, where such strikes have been rather definitely determined in many districts, they seem to show anything but a systematic or uniform grouping (see accom- panying map). SIGNIFICANCE OF THE DURATION AND SUBDIVISIONS OF THE PRE-CAMBRIAN It is quite generally recognized that known pre-Cambrian time was - tremendously long, probably fully as long as all later time put together. It is also generally agreed that there were various periods of more or less vigorous diastrophism, often accompanied by folding, in pre-Cam- brian time, and that diastrophic forces were, as a rule, less pronounced in the later than in the earler pre-Cambrian. Also, in a very general way, the pre-Cambrian has commonly been divided into two great eras— Archeozoic and Proterozoic. It must, however, be recognized that these two subdivisions by no means represent such definite time intervals as do the Paleozoic, Mesozoic, and Cenozoic eras. Where, for example, both the Archeozoic and Proterozoic rocks occur in a given region, the line of separation may represent a time many millions of years younger or older than the line separating rocks similarly classified in some other region. A perusal of the literature shows that this is a real difficulty in the classification of the pre-Cambrian rocks, even of the Canadian Shield itself, in regard to which various writers are by no means in agreement as to where the line (unconformity) between the older and the younger pre-Cambrian rocks should be placed, and some writers even argue for more than two important groups of rocks. GENERAL CONSIDERATIONS 687 In many districts in North America the oldest rocks are simply classed as “pre-Cambrian” not only because there is no valid reason for sub- dividing them, but also because they can not, with any degree of assur- ance, be classified as either Archeozoic or Proterozoic. Again, within groups of rocks classed as Proterozoic, the number of important struc- tural breaks varies from none to several, and we have not as yet devised a satisfactory method of correlating the subdivisions in one region with those in a separate area far from it. These are all fundamental facts which must be duly considered in any effort to work out the pre-Cam- brian structural history of the continent. Evidence has already been presented to show that not all pre-Cambrian rocks were highly folded in pre-Cambrian time. All through his paper, however, Ruedemann considers “pre-Cambrian worldwide folding” to be an established fact. He also recognizes the great length of pre-Cambrian time, and believes that the assumed worldwide pre-Cambrian folding (pages 129-134) originated either from a “long-time, gradual extension of local folding” or from a worldwide simultaneous folding, more likely the former. In any case he advocates the hypothesis that the pre-Cam- brian continent of North America responded to universal folding as a unit (page 75), and that the diastrophic agencies developed a uniformity of trend of the folded structures as indicated on the accompanying map. The writer dissents from all three factors of this hypothesis for the fol- lowing reasons: First. Evidence has already been presented to show that even very old pre-Cambrian rocks have not been universally notably folded. Second. With regard to the proposition that the continent reacted as a unit against folding agencies, it seems to the writer that such a con- clusion is not warranted by the facts. In the light of our great uncer- tainties concerning the subdivisions and correlation of subdivisions of pre-Cambrian time, is it not dangerous to lump together the sum of many local foldings of various times (geologic ages apart) as if they represent a continuous, general process? If they do not represent such a continuous, general process, then the sum total of all pre-Cambrian folded structures can not possibly be used to represent the configuration of the continent as a unit. In this connection we should think of the various great diastrophic movements, widely separated in space and time, which are definitely known to have taken place in North America in post-Cambrian time. During this vast lapse of time, probably no longer than that of the pre-Cambrian, the continent has undergone many im- portant diastrophic changes. As emphasized by Schuchert in his presi- 688 w. J. MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA dential address at the 1922 meeting of the Geological Society of America, the great scenes of diastrophism during the Paleozoic were in the eastern part of the continent, while in later geologic time the scenes shifted to the western part. Nor can it be maintained that these foldings devel- oped progressively in any direction or directions, or, in other words, that successive strips of the continent were affected, as suggested for the pre- Cambrian by Ruedemann, because, for example, the great Rocky Moun- tain disturbance, far within the continent, took place well after the Sierra Nevada folding along the margin of the continent. Furthermore, in post-Cambrian time much of North America has been unaffected by any notable folding. This is an important fact in view of Ruedemann’s ad- vocacy of universal pre-Cambrian folding. In brief, North America in post-Cambrian time has been only very locally affected by notable fold- ings, mostly widely separated in space and time. Surely, then, the conti- nent has not, in post-Cambrian time, responded to universal, long-time folding as a unit! In the absence of anything like definite facts to the contrary, 1s it not reasonable to believe that similar conditions obtained during the vast lapse of pre-Cambrian time ? Third. In regard to Ruedemann’s conclusion that North America re- sponded uniformly to the diastrophic forces of folding, evidence will now be presented at some length to show that such was not the case. OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION GENERAL STATEMENT The map accompanying this paper shows two features—the general trend-lines of pre-Cambrian folding and foliation as observed by Ruede- mann and many of the more important actually observed strikes of pre- Cambrian folds and foliation. Several hundred pieces of literature deal- ing with regions in which pre-Cambrian rocks occur were examined in order to secure the data for the strikes recorded on this map. In many publications the necessary structural data are wholly lacking. Further search would bring to hght a considerable number of other observations, but these would mainly only fill in detail without essentially altering the situation as represented on the map.. Folding and foliation of pre-Cam- brian rocks almost certainly produced after pre-Cambrian time are not recorded, except in a few cases by short broken lines, as in the Appa- lachian region and a few other places. In a few of the recorded cases post-Cambrian diastrophism may have been an important factor, but at most in only a few. OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION 689 LABRADOR, NOVA SCOTIA, AND NEW BRUNSWICK In northern Labrador (A. P. Coleman, 1921) many observations show a strongly predominant north-northeast strike of the pre-Cambrian rocks, or at right angles to Ruedemann’s trend-lines. Late pre-Cambrian rocks in southern Nova Scotia (Faribalt, 1913) are closely folded with east-west strike, thus making a high angle with Ruedemann’s hnes. Several narrow belts of pre-Cambrian rocks in southern New Bruns- wick (Young, 1913) show a general northeast strike, but this seems to be wholly due to infolding with Paleozoic strata, and data regarding the pre-Cambrian are lacking. HASTHRN CANADA Quebec.—In Quebec and Ontario there is probably more of a tendency for Ruedemann’s trend-lines to harmonize with actually observed strikes of folds and foliation than in any other large part of the continent, but even there the divergences are often conspicuous. In the general region about half way between James Bay and Lake Saint John (H. C. Cooke, 1919), in the Opiwaki, Fathers Lake, Windy Lake, Eau-Jaune, Kenoniska, Mettagami, Pontiac, and Brock areas, the whole region appears to have been folded (but by no means everywhere severely) with a general east-west to south 75 degrees east strike, but with some important local variations. In southern Argenteuil County, about 50 miles west of Montreal _ (M. E. Wilson, 1917), there is a persistent strike of north 10 to 30 de- grees east. The Lake Saint John area (Dresser, 1916) shows a general strike about north 10 degrees west for the older pre-Cambrian rocks and about north 30 to 40 degrees east for the younger ones, the older structure lines in this case being almost at right angles to Ruedemann’s trend-lines. In the large Harricanaw area (Tanton, 1919), about half way between James Bay and Lake Temiskaming, most of the strikes range from north 20 degrees west through northwest to nearly east-west. Ontario. — The large, carefully studied Haliburton - Bancroft area (Adams and Barlow, 1910) of southeastern Ontario shows a general north 30 degrees east trend of batholiths and folding, though there are many local variations in the folding, which is of only a moderate degree. The Geneva-Sudbury area (Tanton, 1920) shows considerable folding with a northeast strike. Not far north of Sudbury, however, in the Onaping area (Collins, 1917), the structure lines persistently run northwest, or at right angles 690 w.J. MILLER—-PRE-CAMBRIAN FOLDING IN NORTH AMERICA not only to those of the Geneva-Sudbury area, but also nearly at right angles to Ruedemann’s lines. Collins® says that the generally assumed northeast structural trend of Quebec and Ontario is, after all, not so persistent, and that probably, as work proceeds, “many important irregularities like that in the Onaping area will be discovered in the regional trend.” A glance at the accom- panying map plainly bears out this suggestion. In northern Ontario both the Amisk Lake area (Bruce, 1918) and the Matachewan area (Cooke, 1919) show a north 60 to 70 degrees east strike of folds. The Rainy Lake district (Lawson, 1913) of southwestern Ontario shows ordinary folding of two great sets of pre-Cambrian rocks with a general north-northeast strike. In the Lake of the Woods region (Parsons, 1913) the general strike of older pre-Cambrian rocks is north 60 to 80 degrees east. Manitoba.—The Reed-Wekusko area (Alcock, 1920) of northern Mani- toba shows a north 35 degrees east strike; also, in northern Manitoba, the Ospwagan Lake and the Southern Indian Lake areas. (Alcock, 1920) show a general northeast strike. All three of these strikes cut across Ruede- mann’s lines at high angles. The Knee Lake district (Bruce, 1920) of central Manitoba mostly shows steep dips and strikes ranging from east- west to southeast. WESTERN CANADA Very few observations on the structure of the pre-Cambrian rocks of western Canada seem to be recorded, and these show little or no real harmony with Ruedemann’s lines. In the Athabasca Lake region (Cam- sell and Malcolm, 1919) the older pre-Cambrian rocks have high dips with northeast strike at the lake and a strike varying from north-south to northwest on Taltson River. The younger pre-Cambrian rocks are little disturbed. Between Athabasca Lake and Great Slave Lake (Cam- sell, 1916) pre-Cambrian rocks range in strike from northwest through north-south to northeast, with an average north-south trend. In the Selkirk Mountains and Interior Plateau (Daly, 1913) of southern British Columbia a widespread earlier pre-Cambrian (Shuswap) series is remarkably little deformed, and its strike is north 70 degrees east, or almost at right angles not only to the trend of the Rocky Moun- tains, but also to Ruedemann’s lines. In the southernmost Rockies of Canada (MacKenzie, 1922) a remark- able fact is that earlier pre-Cambrian rocks remained practically unde- ° Ww. H. Collins: Geol. Sur. Can., Mem. 95, 1917. OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION 691 formed (indicated by circle on the map) until the Rocky Mountain fold- ing of the early Tertiary. Of the relatively few definitely known pre-Cambrian structure lines within the vast area of the western half of Canada, therefore, only part of those by Camsell in the Athabasca Lake region are even approximately in harmony with the trend-line announced by Ruedemann. EASTERN UNITED STATES Northern New York—The writer has for many years been making detailed studies throughout the Adirondack Mountain region, and, as already pointed out in this paper, he does not believe that this whole region of earlier pre-Cambrian rocks was ever very notably folded. Neither does the writer believe that there is a distinct northeast struc- tural trend throughout the district. The strikes, which are mostly mag- matic flow structure lines and partly foliation of tilted blocks of meta- morphosed strata, are exceedingly irregular throughout the Adirondacks. The actual facts and their significance are dealt with at some length in a paper*® published a few years ago. The writer agrees with Ruedemann that the area from the northwest- ern border of the Adirondacks to the Thousand Islands has probably been more or less notably folded with a general northeast trend, but this area is really outside of the Adirondack district, which is 120 miles across and in which the structural conditions are different. It is but necessary to glance at the New York State Museum geologic maps made by the writer and others, representing many portions of the region, in order to realize that the facts do not warrant the conclusion that the pre-Cambrian rocks of the Adirondacks show a distinct northeast folded structure. As al- ready mentioned, Collins says that a northeast structural trend through Quebec and Ontario is not nearly as persistent and clearly defined as has generally been assumed. This idea of persistence of trend appears to have originated many years ago, when knowledge of the pre-Cambrian structure of eastern Canada and northern New York was largely con- fined to the Saint Lawrence Valley region, in which a northeast trend does prevail. New England—tIn both western and southeastern New England belts of pre-Cambrian rocks show a general north-south trend, but this struc- ture has largely or wholly resulted from a high degree of infolding with Paleozoic strata: and so this structure has no significance in our present discussion. Mr. Arthur Keith has, however, recently stated to the writer 10 W. J. Miller: Jour. Geol., vol. 24, 1916, pp. 587-612. 692 w.J. MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA that there is some evidence that, in western New England, structure lines in the pre-Cambrian rocks trend somewhat west of north. If so, sucha trend makes a high angle with Ruedemann’s lines. Appalachian-Piedmont region.—The Appalachian-Piedmont region, from southwestern New York to Georgia, contains large bodies of pre- Cambrian rocks; but these have been so highly deformed during Paleo- zoic time, and in part even so closely infolded with metamorphosed Paleozoic strata, that the pre-Cambrian structure lines have been largely obscured, if not in many places wholly obliterated by the Paleozoic deformation. Thus, in the Trenton, New Jersey, Quadrangle (Bascom, 1909) the pre-Cambrian gneisses are folded along with Paleozoic strata, _ and strike north 60 to 80 degrees east with them. According to Miss Bascom : “The prevailing structural features of the Piedmont Plateau are major fold-. ing of the Appalachian type, forming anticlinoria and synclinoria which ex- tend for long distances.” In their description of the Washington, D. C., Quadrangle, Williams and Keith state that “typical Appalachian folds are to be seen in the Piedmont region.” Similar statements are made by .Keith in various later folios. In the Franklin Furnace, New Jersey, folio Spencer says: “No estimate can be given of the extent to which the attitude of the ancient rocks was modified by the earth movements which folded and faulted the Paleozoic formations.” The present general northeast trend of the pre-Cambrian rocks of the Appalachian-Piedmont region cannot, therefore, be assumed to represent pre-Cambrian trend-lines. If, however, the writer, in a recent conversa- tion, properly understood Mr. Keith, who knows the general region so well, there is definite evidence that real pre-Cambrian structure lines are still preserved, and that these run in general more nearly north-south than northeast (see accompanying map). Such being the case, the actual pre-Cambrian structural trend makes a considerable angle with the lines shown on Ruedemann’s map. MINNESOTA, WISCONSIN, AND MICHIGAN Pre-Cambrian structures are well preserved in portions of these States where the great iron ore districts have been carefully studied. Both the Mesabi and Vermilion districts of Minnesota show strikes of about north 70 degrees east for many miles, and the newer Cayuna district (southwest of Mesabi) has a structural trend of north 50 degrees east. The struc- OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION 693 tural trend of the Penokee- Gogebic district in Michigan-Wisconsin is north 30 degrees east; of the Marquette, Michigan, district is east- west, and of the Menominee, Michigan, district is west-northwest. Older and younger pre-Cambrian rocks of north-central Wisconsin (Weidman, 1907) show mostly steep dips with very variable strikes, but a general northeast trend seems to predominate. In south-central Wis- consin (Weidman, 1904) late pre-Cambrian quartzite forms an east-west synclinorium 20 miles long. From the evidence presented, it is clear that in the Minnesota-Wis- consin-Michigan region three districts show strikes in close conformity , with Ruedemann’s trend-lines, while in five districts the strikes make high angles with those trend-lines, thus exhibiting sharp differences within this area. MISSOURI AND SOUTH DAKOTA In the whole vast area, about one million square miles, between the Appalachians and the Rockies, scarcely anything is known about the pre- Cambrian rocks structures, so that any attempt to draw pre-Cambrian structure lines through this area must be largely guesswork. At Pilot Knob, Missouri (Pumpelly, 1873), a relatively small area of pre-Cambrian rock shows an average dip of only 13 degrees and a strike north 50 degrees west. In southeastern South Dakota (Todd, 1903) later pre-Cambrian quartzites in a number of small areas lie in almost horizontal position (shown on map by a circle), and so they are of practically no significance in our discussion. The Black Hills of South Dakota consist of a large core of pre-Cam- brian folded strata and igneous rocks (presumably Algonkian) in which the pre-Cambrian structures are well preserved. The general strike seems to be about north-south (Van Hise, 1890), but there are notable variations, as, for example, in the southern part (Newton, 1880), where there is a northwest strike, and in the northern part Cena, 1898), where mica schists strike northeast. THXAS Two: areas in Texas furnish reliable pre-Cambrian structural data: One is the Lano-Burnet district (Paige, 1912), in the central part of the State, where pre-Cambrian (Algonkian?) strata are distinctly folded with a northwest strike. The other is the Van Horn district (Richard- son, 1913), in the western part of the State, where pre-Cambrian strata strike northeast. In one of these cases the trend corresponds to Ruede- mann’s lines, while in the other it is at right angles to them. 694 w.J. MILLER—-PRE-CAMBRIAN FOLDING IN NORTH AMERICA ARIZONA AND NEW MEXICO In the Shinumo Quadrangle (Noble, 1914) of the Grand Canyon dis- trict steep-dipping Archean schists exhibit a general northeast strike, with local variations. Tilted and faulted, but not folded, Algonkian strata rest on the schists. The Bradshaw Mountains of central Arizona (Jaggar and Palache, 1905) contain pre-Cambrian rocks which were highly folded, with a gen- eral north-south strike, before Paleozoic time. The Globe district (Ransome, 1904) shows an extensive development of steep-dipping pre-Cambrian schist with a northeast strike. Ransome says: “It is noteworthy that the strike of the schistose cleavage runs nearly at right angles to the dominant trend of the present mountain ranges of the region.” Much faulted, but httle folded, Paleozoic strata rest on the schists. A small area of steep-dipping pre-Cambrian schist and granite in the Clifton, Arizona, region (Lindgren, 1905) shows varying strikes, rang- ing mostly between east-west and north 30 degrees east. The Bisbee area (Ransome, 1904), in the southeastern corner of Ari- zona, contains steep-dipping pre-Cambrian schists with a dominant strike about north 25 degrees east. Only moderately folded Paleozoic strata rest on the schists. But little information regarding pre-Cambrian structures in New Mex- ico seems to be available. In the northern part of the State there are several belts of pre-Cambrian rocks, but their north-south trend does not necessarily indicate such a pre-Cambrian structural trend. Thus, in re- gard to the schists and granite of the Cimarron belt Stevenson (1881) says that “the dips of the Archean rocks are much confused.” For the most part, then, in Arizona and New Mexico, the definitely known pre-Cambrian structural trend-lnes make high angles not only with the trend-lines as shown on Ruedemann’s map, but also with the general trend of the Rocky Mountains. NEVADA AND UTAH Few reliable observations on pre-Cambrian structures appear to be available for Nevada, where definitely known pre-Cambrian rocks are not extensively developed. The West Humboldt Range (Emmons and Hague, 1877) shows steep-dipping schists and gneisses with strike north 38 de- grees east. The Snake Range of eastern Nevada (Weeks, 1907) contains steep to moderately steep dipping quartzite with a west-northwest strike. OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION 695 Pre-Cambrian rocks are not extensively exposed in Utah, and satis- factory structural data are scarce. In Big Cottonwood Canyon (Em- mons, 1877) of the Wasatch Mountains near Ogden, pre-Cambrian quartzites and schists, with rather high dips, strike northeast, and in Little Cottonwood Canyon schists strike northwest. In the small Farm- ington (Hague, 1877) area of the same general region, pre-Cambrian rocks strike about north-south. According to Blackwelder (1910), a considerable body of Algonkian strata lies within the Wasatch Mountains east of Ogden, but structural lines within it are not reported. The main body of rock in the midst of the Uinta Range is late pre- Cambrian quartzite only very moderately disturbed and with a general east-west strike of post-Cambrian origin. It is, therefore, clear that the few pre-Cambrian structure lines above recorded from Nevada and Utah show widely varying strikes, mostly notably divergent from Ruedemann’s trend-lines. COLORADO This State furnishes an unusual number of records of pre-Cambrian structure lines from both large and small areas. In the vicinity of Silver Cliff (Cross, 1896) pre-Cambrian gneisses strike northeast. Small areas of pre-Cambrian (Archean?) schists near Pueblo Gilbert, 1897) show strikes varying from north-south to northwest, with little disturbed Cretaceous strata resting on them. In the Rico Quadrangle (Cross and Ransome, 1905) a small area of pre-Cambrian schist with steep dips strikes east-west, while within a few miles of it folded Algonkian strata show strikes varying from north 10 to 30 degrees east, with scarcely folded Paleozoic strata on them. Both Archean and Algonkian rocks are well represented in the Needle Mountains Quadrangle (Cross and Howe, 1905), the general strike of the former swinging from a little east of north to nearly east-west, while the latter (Algonkian) ranges in strike from east-west to west-northwest. Both sets of rocks were notably folded before the opening of the Paleozoic. Steep-dipping Algonkian strata in the Ouray Quadrangle (Cross and Howe, 1907) show an average east-west strike, but part or all of this deformation belongs to post-Cambrian time. In the Telluride Quadrangle (Cross, 1899) a-small area of rather steep-dipping Algonkian strata exhibits a well preserved strike north 65 degrees west. 696 Ww.J. MILLER—-PRE-CAMBRIAN FOLDING IN NORTH AMERICA ‘Fhe Engineer Mountain Quadrangle (Cross, 1910) contains Archean eneiss and schist in its southeastern part with strikes varying from east- west through northeast to nearly north-south, and Algonkian strata with nearly east-west strike in its northeastern part. The Pikes Peak area (Cross, 1894) contains some pre-Cambrian eneisses with a north-northwest strike of foliation. Pre-Cambrian rocks in the Georgetown Quadrangle (Ball and Spurr, 1905) exhibit an excellent schistosity, with a prevailing east-west strike. HKarlier pre-Cambrian gneisses in Rocky Mountain Park show a gen- eral north-south strike of fohation, while steep-dipping Algonkian strata in Thompson Canyon, just east of the park, strike about east-west. The southern portion of the Park Range (Van Hise and Leith, 1909) of northern Colorado consists of pre-Cambrian rocks with a prevailing north-south strike, which changes to a general east-west strike in the northern portion of the range. WYOMING Pre-Cambrian structural data are obtainable for several districts in the southeastern one-fourth of this State. The Encampment district (Spencer, 1904), near the middle southern border of the State, shows a large development of pre-Cambrian strata with a distinct strike nearly east-west for over 20 miles. This strike is the same as in the adjacent Park Range of Colorado. In the Medicine Bow Range (Hague, 1877) a large development of steep-dipping Archean gneiss, schist, and quartzite strikes about north 20 degrees east. In the Laramie-Sherman Quadrangle (Darton and Blackwelder, 1910) of southeastern Wyoming pre-Cambrian gneiss and: schist are well devel- oped, with a prevailing strike north 70 degrees east. — The Hartville district (W. S. Smith, 1903), in the eastern part of the State, contains Algonkian schist, limestone, and quartzite with practi- cally vertical dips and a generally nearly east-west strike. A large area of pre-Cambrian granite is exposed in the Big Hor » Mountains. (Darton, 1906). It is devoid of foliation, and so gives no clew to the pre-Cambrian structure of this region. It is involved, with Paleozoic strata on either side, in a gentle anticlinal structure. This occurrence is of interest, however, because it is such a large body of pre- Cambrian rock which has never been subjected to much pressure. Pre-Cambrian rocks are extensively exposed in the Wind River Moun- tains, but not much seems to be known about their structure. In 1879, however, Endlich said: OBSERVED STRIKES OF PRE-CAMBRIAN FOLDING AND FOLIATION 697 “The granites are flexed and contorted in every possible direction and con- tain simple bands of micaceous and chloritic schists which denote the original planes of stratification.” In the Gallatin Range of Yellowstone Park (Hague, 1899) a relatively small area of pre-Cambrian schist shows a general north-south strike. MONTANA AND IDAHO There are several areas of pre-Cambrian rocks in the western half of Montana for which more or less structural information is available. In the Little Belt Mountains (Weed, 1899) an area of Archean has steep dips and a general east-west strike. Resting on the Archean are very moderately folded Algonkian and Paleozoic strata. A small area of Archean gneiss and schist in the Fort Benton Quad- rangle (Weed, 1899) shows steep dips and very variable strikes. The geological map of the Three Forks Quadrangle (Peale, 1896) shows large areas of Archean gneisses, but their structure is not de- scribed. There are also Algonkian (?) marble and schists which were metamorphosed and folded (structural data not given) before the dep- osition of an unaltered Algonkian sedimentary series, which latter is intricately infolded with Cambrian and Cretaceous strata. In the Marysville district (Barrell, 1907) near Helena, Algonkian strata are only gently folded with very irregular strikes. The prevailing strike seems to be northwest, but Barrell speaks of a cleavage structure with a northeast trend. In the Philipsburg Quadrangle (Calkins and Emmons, 1913) Algon- kian strata are extensively exposed with exceedingly variable strikes and with only a general parallelism with the late Cretaceous folds, so that in part. the folding may be of pre-Cambrian age. The great body of Algonkian strata in Glacier Park has a long, wide, gentle synclinal structure, with nearly north-south strike, but this struc- ture was probably developed at the time of the thrust-faulting in the early Tertiary. The Coeur d’Alene district of Idaho (Ransome and Calkins, 1908) contains much pre-Cambrian stratified rock notably folded with very irregular strikes, but with a northwest trend somewhat prevalent. CONCLUSIONS REGARDING THE CORDILLERAN REGION From the data above presented it is evident that there is no predom- inant pre-Cambrian structural trend through the Cordilleran region of the United States approximately parallel (north-northwest) with the trend of the Rocky Mountains. A glance at the accompanying map will’ XLVI—BULL. Grou. Soc. AM., VoL. 34, 1922 698 w.J. MILLER—-PRE-CAMBRIAN FOLDING IN NORTH AMERICA show that decidedly more of the pre-Cambrian trend-hnes run from east- west to about northeast rather than approximately north-northwest. It is, therefore, a very significant fact that the prevailing direction of pre- Cambrian folding and foliation is across the Cordilleran region rather than parallel with it. Considering this fact, together with the meager structural evidence from western Canada and the practical absence of definite evidence from Alaska and Mexico, it-is clear that there are no sufficient grounds for advocating a general north-south trend of pre- Cambrian folds and foliation through western North America, as has been done by Ruedemann. This matter is all the more significant when it is realized that the western half of the whole continent is involved! GENERAL CONCLUSIONS Some of the main conclusions in regard to the pre-Cambrian folded and foliated structures of North America which seem to be warranted as a result of the evidence presented in this paper are as follows: 1. The older known pre-Cambrian rocks of North America have not been universally intensely folded, as has heretofore been commonly as- sumed. In some districts they have never been more than very moder- ately folded, and in other districts they have been moderately or highly folded only since pre-Cambrian time. In many districts they were, how- ever, highly deformed in pre-Cambrian time. In many cases the proba- bility of the development of steep dips and more or less folding through the agency of magmatic intrusion, under the influence of but little lateral pressure, should be considered. 2. In any attempt to decipher pre-Cambrian diastrophism in North America, careful discrimination should be made between folded struc- tures of pre-Cambrian rocks developed in pre-Cambrian time and those subsequently produced. In many districts this has not been done and in some cases it is impossible. 3. Because of the vast length of time involved and the great uncertain- ties of subdivision and correlation of pre-Cambrian rocks in various parts of the continent, we are still in the dark in regard to the number, extent, severity, and correlation of crustal deformations of pre-Cambrian time. More particularly, the facts do not warrant the conclusion that there was a great continent-wide so-called “Laurentian Revolution” marking the close of a rather definite portion of pre-Cambrian time. 4. The plotting of many definitely recorded strikes of pre-Cambrian folding and foliation (see accompanying map) does not indicate “a grand and simple curvature,” changing from a northeast direction in the east- ern part of the continent through east-west in the interior to approxti- GENERAL CONCLUSIONS 699 mately north-south in the western part of the continent, as advocated by Ruedemann. 5. There is not sufficient warrant for a statement that North America reacted as a “unit against the diastrophic forces active in pre-Cambrian time,” as advocated by Ruedemann. On the contrary, because of notable variations in structural trend, even in local portions of the continent (see map), and because of the localization of orogenic forces, both in space and time, during the very long post-Cambrian history of the conti- nent, it is more reasonable to believe that similar localization obtained during pre-Cambrian time. 5. The absence of pre-Cambrian structural data from vast areas (fully one-half) of North America causes a large element of uncertainty to enter into any attempt to generalize with regard to the trend-lines of pre-Cambrian folds and foliation. Discussion Dr. R. Ruedemann sent the following letter, which was read in open- ing the discussion : It is just as well that Professor Miller attracts attention to my paper on the ‘Existence and Configuration of pre-Cambrian Continents” by attacking its premises. This is always the surest means of keeping a new-born idea from the limbo of the still-born and forgotten. The points which Professor Miller proposes to raise, according to the pro- gram, refer to premises that had been recognized by me as the ones that needed protection and that therefore have been frankly stated in the paper to be open to discussion and the evidence for which has been fully presented, as far as the limited space allowed. The first point is that the Archean basement complex in North America has not everywhere undergone severe metamorphism. This is, as far as I can see, of no critical importance for the solution of the problem involving the presence and configuration of the pre-Cambrian continents and may, therefore, be passed without comment. The second point is that the Archean basement complex has not been uni- versally intensely folded. In this regard Professor Miller disagrees, as far as the Adirondacks, his field of study and experience, is concerned, with all the other geologists that have worked in the Adirondacks, and that fact is set forth in my paper. As my conclusions must be based, of course, on the con- sensus of authors and not on a single dissenting view, the latter, however interesting, is of no account in this matter. The third point is that ‘the pre-Cambrian folding does not exhibit such uniformity of direction as has been recently advocated” (by the writer). The claim that the folding is uniform in its grand outlines is based on the evidence gathered from the pre-Cambrian literature of the world there cited and will have to stand or fall with the correctness of the many observations. quoted. 700 w.J. MILLER—-PRE-CAMBRIAN FOLDING IN NORTH AMERICA It may be added that more corroborative literature is at hand, and that arti- cles which have appeared since the paper was written nicely fall in, in the pre-Cambrian trends given, with those merely inferred for the regions in ques- tion. It should also be pointed out, as has been fully done in my paper, that while the author speaks principally of the fold directions, the trend-lines of the pre-Cambrian rocks there under discussion comprise not only the fold directions, but also the direction of the foliation, schistosity, and of the major axes of the batholiths, all of which phenomena form a causally connected group. It should be remembered that these criteria, in a paper dealing with their continental or even world-wide order of magnitude, can not be judged fairly and properly from the study of a very limited area in the Adirondacks alone, however thoroughly this may have been done. Professor Miller further points out that “the vast length of pre-Cambrian time and the uncertainties of its divisions, as well as the difficulty in many places of distinguishing rock structures which developed during pre-Cambrian time from those produced by post-Cambrian diastrophism, are antagonistic to any attempt to decipher the pre-Cambrian configuration of the continent.” These difficulties are fully recognized in the paper and stated as such; but since also the general parallelism of the greater subdivisions in the different continents, of the northern hemisphere at least, is set forth following the views of Adams, Kemp, Willis, and others, and it is further brought out that the folding and its associated phenomena, as seen now in the pre-Cambrian rocks, is the summation of that of all pre-Cambrian eras and is treated as such; the criticism is beyond the point. Pre-Cambrian and post-Cambrian folding have been carefully separated in the paper, and areas where the latter is evident have been omitted from the discussion. As the conclusions set forth in my paper are based on a great mass of data seattered in the literature, they must stand or fall, I repeat, with the correct- ness of the: many observations there recorded and with those yet to be made. All that I, therefore, ask is that these conclusions be given a fair and unbiased trial by those engaged in the study of pre-Cambrian geology and paleogeogra- phy, and I have no doubt that such will be granted by the great majority of geologists. | Prof. A. P. Coteman: The early pre-Cambrian rocks of Canada rep- resent only the foundations of the original mountains. They have batho- lithic forms and the schistose structures strike in all directions around the great batholiths, but the batholiths themselves generally show an elongation in a direction roughly parallel to the edges of the pre-Cam- brian Shield. In northern Ontario the structures run usually from north 50 to 80 degrees east. The ancient mountain ranges overlying the batholiths probably ran in the direction shown by this trend in the elongation of the batholiths. Miss Margaret FuLtuer: The results of a recent detailed field study of the pre-Cambrian geology of the Front Range in Colorado, from the DISCUSSION 701 Continental Divide eastward through the Valley of the Big Thompson River to the foothills, may shed some lhght on the question of the pre- Cambrian structure of the Cordilleran area. The pre-Cambrian consists of a series of highly metamorphosed sediments, mainly schists, intruded by two granites, with their accompanying wealth of pegmatites. The structure is one of numerous batholiths, which have arched and meta- morphosed the sediments in a long north-south belt, the more intense metamorphism being near the center of the range and extending north and south in a belt which grades eastward into a similar north-south parallel belt of less intensely metamorphosed rocks. This would indi- cate that the original pre-Cambrian structure had been one of linear in- trusion lines, arching up a north-to-south area. Similar structure in the region north and west of Colorado Springs suggests the same conditions. Probably the more recent arching, which uplifted the Front Range as it lies today, took place along the old pre-Cambrian line of diastrophism. Reply by Professor Mrtuer: I regret that Dr. Ruedemann is not here in person. His discussion, based entirely upon the very meager state- ments in the abstract of my paper, would, I believe, have been consider- ably modified had he heard my paper in full. In his paper (page 75) Dr. Ruedemann states it is an established fact that the Archean basement complex has undergone complete meta- morphism. I differ from him on this point, but I agree with him that this matter is not necessarily of critical importance, as shown in my paper. In the second point of his discussion Dr. Ruedemann imphes that my whole field of experience is the Adirondacks, but this is by no means true. He also states that all geologists, except myself, who have worked in the Adirondacks agree to the proposition that the whole Adirondack region has been severely folded. This is hardly a fair statement of the situation, because, in the first place, I myself accepted the idea of severe folding and compression of the region until about ten years ago, when I began to critically examine the field evidence, and, in the second place, some of the workers he cites studied only the northwestern flank of the Adirondack region, where I, too, believe there has been more or less fold- ing; some of the workers have never seriously argued for severe folding, and only two of them have recently really advocated a severe folding of the whole region. Now, as set forth in my paper, it is not a foregone conclusion that the two workers who have advocated severe folding are right and that 1 am wrong, certainly not in view of the fact that the array of evidence presented by me in 1916 (Journal of Geology, volume 24, pages 587-619) has not been attacked. The fact that I have done a greater amount of detailed field-work on the pre-Cambrian rocks of 702 w.J.MILLER—PRE-CAMBRIAN FOLDING IN NORTH AMERICA northern New York than anyone else ought to make my conclusion worth something. | In his third point Dr. Ruedemann defends his conclusion regarding uniformity of direction of pre-Cambrian folding by saying that the con- clusion is based upon evidence gathered from an extensive literature on pre-Cambrian geology. My answer is that for years I have been study- ing this same hterature; that I have very recently reviewed hundreds of pieces of this literature, and that I find the evidence pointing to a con- clusion different from that of Dr. Ruedemann. Like him, all I ask is that the evidence and conclusions which I present shall be given “a fair and unbiased trial’ by students of the pre-Cambrian. Dr. Ruedemann’s statement falls wide of the mark, as my paper plainly shows, when he says that I judge his paper, dealing with a worldwide order of magnitude, “from the study of a very limited area in the Adi- rondacks alone.” Finally, I do not agree with Dr. Ruedemann that he has carefully separated cases of pre-Cambrian and post-Cambrian folding, as brought out in various parts of my paper. If, as Professor Coleman states, the pre-Cambrian structures of north- ern Ontario mainly run from north 50 to 80 degrees east, they certainly are not even approximately parallel to the edge of the Canadian Shield in that general region. Furthermore, on the basis of Coleman’s own work, the pre-Cambrian structure of northern Labrador is conspicuously out of harmony with Dr. Ruedemann’s trend-lnes. Miss Fuller’s observations in a local portion of the Front Range of Colorado do harmonize with Ruedemann’s conclusion, as my map shows; but the pre-Cambrian structural trend is there exceptional for much of the Rocky Mountain region of the United States, even that part of the region just to the north, in Wyoming. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 703-720 DECEMBER 30, 1923 GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY 1 BY ALFRED C. LANE (Presented before the Society December 30, 1922) CONTENTS Page SaaS RENAE ee Sede eet ed aeaN Gs Mee te Ds wie gta came al moa diase Sveen aib stem ea gle “ee epee 703 epee UM en Sere ee oy ha Se ei ise Se RAS ESONk Se eA a 704 peTNBER HGR MEO ONES el eree ce ce reve, as avers Gone, Sue es oowlare Sm soleinw tare Oe eae ce wie See div dale 705 Pe SuUpPeTION NOt CfIClENt. 22.6.6. ee wee ee ee FS oh otiee eae Shack ache Ts. shone veto) NSRP DIE, BIRT RUC SIU 12 (2 ORR Se (Oval Mathematical discussion.......... PAS Beer tt Meee Sahel ona eo re ore ei aiial aint on sakes 715 Grrerncauses Of JoOw, STAdIent i... 22. 5 ak ee eee eget es tla dsbaewep on ais eal os 719 LGV SIE TESST TIS RE ERR IRS ati ae at Sratiel Gralaec ets .cbeme 720 SUMMARY _ The rate of increase of temperature in the Lake Superior mines aver- ages about one degree per 105 feet, but is greater in depth, about one degree Fahrenheit per 90 feet. While the mean air temperature in Calumet is about 39 degrees Fahrenheit, the mean ground temperature is 43 degrees (42.6 degrees Fahrenheit), owing to the blanketing effect of the snow in winter. This increase of gradient is due to an increase of surface temperature about 10,000 years ago; for, by taking the gradient below 4,000 feet and producing it to the surface, we find a surface temperature of 32 degrees Fahrenheit, that which the ice bottom may have had. The time since the rise in temperature is found by seeing how much the scale of time may be enlarged in the probability curve connecting the temperature and time for a flow of heat due to a sudden rise of temperature, and yet have the curve lie under one constructed to show the excess of observed tem- perature over that due to the bottom gradient. There are indications of a milder climate between the Ice Age and the present. 1 Manuscript received by the Secretary of the Society February 20, 1923. (703) 704. A.C. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY The deep gradient of one degree Fahrenheit in 90 feet, equal to one degree centigrade in 49.5 meters, is not so far from that which is normal to the earth, but it is easily explained by the absence of pyrite or signs of any recent exothermal reactions in the rock, by exhaustion of heat from below in early times, by the abnormal thickness of the crust indicated by the observations for isostasy, and the less radioactivity of basic rocks. Reactions leaving CaCl, in solution, and hence endothermal, do not need to be inferred. | Lake Superior has no appreciable effect on it, first, because the deeper temperature of Lake Superior (39 degrees Fahrenheit) is practically the same as that at Calumet; secondly, because the gradient near the lake is nearer the normal; and, thirdly, because the lake is too far from Calumet, compared with the difference in elevation, to have an appreciable effect. _ Similar postglacial heat waves should be and may be noted in the tem- perature of other deep wells. HISTORICAL The first observations on underground temperatures on Keweenaw Point were made back in 1847 and were reported by C. T. Jackson,? and are tabulated in my report on page 759. He rightly assumed 43 degrees as the surface soil temperature—that is, it is probably within one degree of this for the yearly average, which varies a little from year to year, as the table shows. The greatest depth then reached (with no account of the topography) was 236 feet, where the temperature was 45 degrees Fahrenheit. No account has been taken of mean depth from the surface, nor allowance for the topography in any of the measurements. The next important observations were made by H. A. Wheeler.* Sub- tracting one degree in 105 from his upper measurements, we get 41.7 degrees Fahrenheit for the initial soil temperature; and, doing the same thing for his lower measurements, we find a temperature of 42.5 degrees Fahrenheit. In 1894 J. F. Roberts tested the bottom of the Central Mine. In 1901 I found in the Champion copper mine a temperature of 44 (5 degrees) in the first level, 130 feet below surface, and 45 degrees in the second level, 250 feet down. Making the same deductions of one degree per 105 feet, we have 43.3 degrees Fahrenheit respectively, 42.6 degrees for the surface temperature. In August a strong flow from (as was told me) 80 feet down in Calumet and Hecla hole 10, on section 16, 2 Annual message to Congress and accompanying documents, 1849-50, Part III. 3 American Journal of Science, vol. xxxii, 1886, pp. 125 to 138; also in Transactions St. Louis Academy of Science, my report, p. 760. : , Ws 7 F et i, eae ee ee Pt P . - « . : a ' ( c ; r a op-— ft anid st ‘3 eae yi adisS ~~ 7 F ths * + nies *, sg S- 7 X ~— Ss > ‘ . r i" ot o8F ci say Dowie’ uped oft YS weeds 1 uri, i ab pn cd hetaskb tied iw ee ylke avt— {) < | asi ashi rh bite 0,2 te Mgot or . o ¢ 4 ; os af? dokiw “i o yeu to s«ilaisu SPC 0 } se : wpe : - ‘ me moaxe “8 99 eicanivads att xd Sault, oe. 4 Me Mets , 7 € SO nD 4 scoul - TT peat + Ty Bees tx Towlhys i‘ + 2H t ‘ “ _ - a ° 4 . a A f _ hap nialien * is “ : y ; : é - sa ; . : i > ae 3 . ~ -, ee = re % | » 7 7 ° 5 $ ~ : : ; x, 4 ae ris wo8 “© 7 4 re 2 , , os : +? ” r me an - aint , 4 : ~~ « ; 7 . rT its . os p 7 tox . e sel SF TSeSalii ‘ F] ; , ® te? pa 2 r » . i j ; ‘ 7 s : - - : 3 ivi re - re) 2 ay Ls st? #¢ - ; ,. . 4 J 2 fey ¢ » © ; —_— ag } ‘ ‘ , TNO eat? a ce. 4 ; ‘ ; > 8h * bh 3 Se A r - ; 4 4 ; — 7 : 7 r bam A z : H i ° 7 H 3 d gan probability curve ance from left to t, and the circles bserved at depths xpected from the the temperatures 20pper mines, by idicate a greater bottom gradient, the right and a re 2, so that the ent as measured HISTORICAL 705 township 56, range 33, gave 43.3 degrees, one of the very best observa- tions—that is, not less than 42.6 degrees Fahrenheit surface temperature. These variations are but such as might be expected in the mean soil tem- perature from streaks of warm years and cold years, as we see from the table of temperature below, from the State Weather Service. In addition - to these variations, we have inaccuracies in thermometers, and in my case at least the thermometer was a pocket one, too small to read fractions of a degree accurately. There is also allowance to be made for mine ventilation, tending to increase readings below 60 degrees and decrease those above 70 degrees. There is also the fact that in no case was the real mean depth below the topographic surface computed nor the effect of underground circulation allowed for. All these factors must be al- lowed for if closer results are to be obtained, though they hardly will change the results 5 per cent. While State Geologist, I made various observations in 1901, 1906, and 1910, assembled in my report on the Keweenaw series, and a very im- portant set was made by S. Smillie, engineer of Quincy Mine. All ob- servations were assembled in my report in 1911, and all the more impor- tant were reprinted by N. H. Darton in United States Geological Survey Bulletin 701. C. EH. Van Orstrand is continuing that work. There is also a method of attacking the problem of mean soil tempera- ture from the Weather Bureau side, thus: Find the mean temperature for a term of years, preferably just preceding the observation. Then assume that for the months when the mean temperature is below freezing, the ground temperature is freezing, for it is known that frost does not go down into the ground more than for a couple of feet. If we also assume that for the first month in spring, when the temperature averages above freezing (April), the ground temperature averages about freezing by the melting snow, we come to 43.7 degrees—a temperature within a degree of the temperatures directly measured. | SUMMARY OF DaTa The data have been so summarized in my report in 1911, and especially in Darton’s valuable Bulletin on the Geothermal data of the United States,* that it seems hardly needful to do more than give a few important figures to save the bother of reference and add a few observations I re- cently made, especially as I understand C. E. Van Orstrand has a yet more elaborate report in hand, which may precede this, and it is to be hoped will include in full the valuable records of the Calumet and Hecla Mine for Alexander Agassiz. 4U. S. Geol. Survey Bulletin 701. DEPTH SCALE FOR MICHIGAN 46,000 HiGuRY 1.—Differences from deepest Gradient in Michigan Probability curve in left corner. Figure 1 shows by the heavy black area in the lower left corner the probability curye (1—Pm), unity for m being indicated by a distance. The same distance from left to right as the depth of 1,000 feet, and in ordinates 10 degrees Fahrenheit, and the circles indicate the number of degrees by which the actual rock temperatures observed at depths corresponding to the abscissas are in excess of those which might be expected from the temperatures and the gradient at the bottom of the mine, Figure 2.—Temperatures in Michigan Figure 2 shows to the same depth scale, running from left to right, the temperatures (referred to the scale on the left) for various depths in Michigan copper mines, by hollow circles with a radius equivalent to one degree. Half circles indicate a greater range of probable temperature. The heavy black line indicates the bottom gradient, one degree Fahrenheit in 90 feet. Figury 3.—Temperatures in Lake Well, West Virginia Figure 3 shows by solid black circles with a temperature scale to the right and @ depth scale below, with the units in each half the size of those in Figure 2, so that the slopes are directly comparable, the temperatures and the bottom gradient as measured by C. H. Van Orstrand at Lake, West Virginia. eS 706 A.C. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY Degrees Fahrenheit The hottest and deepest reading was in the bottom of the Tamarack, at (S,560)>: feet 20-2. Us uit Se pee eh he ee Fa ec Ls ie cae eee, 91.4 A more reliable record is by C. E. Van Orstrand, on the 81st level of the Calumet and Hecla (checked by myself in August, 1922, as 86 degrees centigrade), at 2900. feetecs Se. ee Ooo Se ee 86.4 I also found at the 78th level (about 4,700 feet from surface)......... 84 at the T4th level, about "4,480 feet. i. vis os. ee ee 82 at the 22d level, Ahmeek (1,870 feet), short drill-hole.... 65.4 level, -Ahmeek,. dirt: on. floors. 2cJ “st - bees 62.3 Isle Royale No. 5 shaft, 21st level (2,664 feet)..... about 66 19th: level (2,425 feel)... kee 63 Champion No.4 shaft, Sth: level. 2.2202... 2.2. ~. sos eee 51 17th level warmed by mine circulation, probably, compare— 54 Observation in 1909 on the 13th level, when the mine was NE WET 6 oo ok eS SE a Se pene ee Seti elo ab Gace ae ayia Arcadian Consolidated (New Baltic shaft), 1,100-foot level—that is, about (900 feet down)................. 58 The more reliable® observations are, howeyer— Tamarack "5 -(4:662).- TCG s ooo wc waters a Ae Ve ke 8 Oe eee ne os ee ee ee 2 Quincy .(3;875. feet) =" (S. Smillie yo se nye ee as re See 76 (3:856 SIGEBR) os 2 Sa ie eo Ge oes ee 74 (S,24G | LECL) Po coi ielee cia wise &, oe mle) 5m, 6 Sty one aa ap ge (1530 BECE) Sos: sala ciate» OW seine 6 bits ans oie eee 52 C. J. McKie reports the temperature of water flowing from a drill-hole in the Baltic Mine of the Copper Range Company, 36th level (3,277 feet), 71 degrees. On the 3,950-foot level, 1,200 feet from the shaft, rock and air temperature (3,599 feet), 74 degrees. J. W. Alt, chief engineer of the Montreal Mine, Hurley, Wisconsin, reports the tempera- ture of a drift at the bottom of that mine (1,676 feet down) as 19 degrees to 1914 degrees centigrade, and of water flowing from a drill-hole, 70 gallons a minute, as also 1914 degrees centigrade, equal to 67 degrees Fahrenheit. The following table, for which we have to thank the Bureau of Mines and Mr. T. Dengler, the agent of the Mohawk Mine, shows not only the temperature at various depths, but by the dates, which may also be useful hereafter, something of the error to be expected in observations owing to ventilation, circulation, and variation of temperature in the air between winter (February) and summer (August). The dip of the mine varies 5 Numbers in parentheses are vertical depths from the surface, supposed to be flat. 6 The depths given by the engineer are below Lake Superior. To this Darton adds 500 feet and I here 550, and I have changed my views as to the more reliable observa- tions. Crosscuts are better sometimes than short drill-holes, farther from ventilation, less affected by boring. SUMMARY OF DATA 707 from 36 to 38 degrees, so that the depths from the surface, which varies not over 100 feet, are about 6/10ths (0.6) of the depth down the shaft. _ It will be noted that the air at the bottom varies not over 3 degrees Fahrenheit from the rock and water temperature, even when there is a wide range in the surface temperatures, and that it is practically satu- rated, even when much warmer than the air outside, showing the evap- oration that goes on and makes the mine dry and even dusty, although there is moisture in the rock. The bottom temperature of 56 degrees at something like 1,400 feet vertical depth beneath the surface is what might be expected. a Vv 08 A.C. 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Cc. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY LAKE SUPERIOR NOT EFFICIENT In his work in 1886, the first that brought into relief the low gradient of the copper mines of Michigan as compared, for instance, with those in Montana (the North Butte Mine at Butte, Montana, has at 2,800 feet a rock temperature of 107 degrees Fahrenheit), Wheeler suggested that the low gradient might be due to the cooling effect of Lake Superior. Unfortunately, this suggestion was taken up by Koenigsberger, the great European and world writer on this subject, in his paper before the International Mexican Congress.’ When he speaks of a “small” gradient, he means thereby one in which are few feet needed to obtain 1 degree rise, 9 degrees Fahrenheit = 5 degrees centigrade, 1 degree Fahrenheit for n feet = 1 degree centigrade for 0.55 meters. Thus no change in temperature at all would be a “large” gradient! He says (page 12) that the geothermal gradient is “greatest” near the surface, which agrees with ~ what should be the case if the mean surface temperature has risen since the Ice Age. On the other hand, “the more recent the eruption, the smaller the geothermic gradient.” ‘This is altogether in harmony with the contrast between the temperature of the copper mines of Butte, Mon- tana, where the igneous activity is Mesozoic, and those here cited, where the igneous activity is probably before the Taconic uplift and pre-Ordo- vician. Thus Wheeler’s suggestion is spread through the literature. It ean not be too strongly emphasized that Lake Superior has nothing to do with the gradient. In the first place, it will be noticed from the table above that the mean annual temperature of Calumet is only a degree or so from that of the bottom of Lake Superior, which is that of the maximum density of water (38.8 degrees Fahrenheit), a mere trifle compared with the differences in temperature that would exist had Michigan the same gradient as Montana. In the second place, Lake Superior is 5 miles away, and the lateral effect of cooling on a point only one mile down, common sense would indicate could be but slight, even if B. O. Peirce had not figured it out with a thorough use of mathematics in volumes 34 to 38 of the Proceed- ings of the American Academy of Sciences.® In the third place, the gradient in the Freda well, down on the edge of Lake Superior, is higher than in the deep mines back from the shore. 7 Also Transactions Institution of Mining Engineers, vol. xxxix, part 4, New Castle- upon-Tyne, England, p. 11 of excerpt. 8 Vol. 34, pp. 22-25; see also vol. 36, pp. 1-16; vol. 38, pp. 651-660, or Williamson and Adams, Physical Review, n. s., vol. xiv. 1919. pp. 101, 1038. EFFECT OF LAST ICE AGE Tht The water rose in an artesian flow from a depth somewhere between 709 and 950 feet at a temperature of about 55 degrees, and the gradient is not far from one degree in 70 feet. It certainly can not be any lower than one degree in 84 feet, as given by Darton. EFFECT OF LAST Icr AGE If Lake Superior has no cooling influence, what is the cause of the low gradient? It may be that this is the normal gradient, due to the flow of internal heat from far below. Such a gradient would give a temperature of 1,500 degrees centigrade in 73.5 kilometer, or 2,000 degrees centigrade in 98 kilometer depths, from which lavas might be supposed to come. Then others generally found would be abnormal and affected by chem- ical reactions, and this is certainly often the case. But one thing that clearly appears from the data should be considered, and that is that the rate of increase is more rapid at the bottom. This, to which we shall return, might be laid to approaching a source of heat below, for in that case the curve of heat would be steeper as we go down, for not only is the heat increasing, but the rate of increase of heat increases as we ap- proach the source of heat. This would imply a continued acceleration of the increase of heat with deeper mining. But in that case we should expect an abnormally high gradient at the bottom, which is not true. The Montana mines reach a greater temperature in half the depth—tfor example, the North Butte Mine has at 2,800 feet a temperature of 107 degrees Fahrenheit, and the igneous activity there has been much more recent. The same effect, however, would be produced if the surface tempera- ture had grown milder in later years. It would be the same kind of effect as the progress of a summer wave of heat downward, which has been studied® by Callendar and McLeod and many authorities of weather bureaus and agricultural stations. That there has been such an effect is certain, for we know that not so many thousands of years ago there was a time when the ice covered this region. There are, indeed, kettle-holes and other signs of melting ice blocks right over the Tamarack and Calumet and Hecla mines. Then we know that this was succeeded by a lake—Lake Duluth—which Leverett has studied,?® and that probably relatively soon thereafter the land emerged. What the changes were thereafter in ground temperature ® Transactions Royal Society of Canada, vol. i, 1895, sec. 3, fig. 6; see also vol. ii, ps 109}-andi vol. iti,p, 31. 10 Michigan Academy of Sciences, 1917. 712 A.C. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY we do not so well know, but there are some who speak of a relatively mild postglacial climate, which the underground temperatures indicate, as we shall see. | If, then, we assume that when the ice had melted, the temperature rose rather suddenly to the temperature of the bottom of Lake Superior (the temperature of the maximum density of water), and that Lake Duluth was like Lake Superior in that respect, we shall make a reason- able assumption. Yet it is possible that the ice which once filled the kettle-holes may have taken a hundred years after the recession of the ice-sheet to melt. If we assume that since the land emerged above Lake Duluth the mean temperature did not drop, but remained somewhere between the temperature of the maximum density of water (38 degrees Fahrenheit) and the present temperature or higher, but not lower, we make also a probable assumption. There was no readvance of the ice- sheet front, so far as I learn, after the abolition of Lake Duluth. Now the flow of heat waves into the ground has been a subject of in- vestigation many times,” and if we can give definite values for the varia- tion of surface temperature, we can calculate the underground tempera- tures. This we can not do exactly, but we can derive an approximation which will answer present purposes and can be handled by any geologist so as to adapt it to various data without undue labor in getting approxi- mate results, which will be as accurate as present facts warrant. Suppose that the Ice Age lasted long enough so that the temperature gradient was for great depth and below the depths of observation ad- . justed to the surface temperature of freezing (32 degrees Fahrenheit under the ice-sheet), and that at the end the temperature rose to 42 de- grees and stayed there. This rise would make an addition to the previous temperatures in the shape of a logarithmic curve of the probability inte- gral. It is the curve figured in figure 1. The maximum ordinate is determined by the rise in temperature. In the case chosen this is 10 degrees. If one wishes to apply it to some other change in surface temperature, one increases the ordinates, or, what is the same thing, changes the unit of the scale of ordinates in proportion. | The ratio of the increase of temperature for various depths is given by the other ordinates to the surface increase. The depths are connected with the abscissas in this way, that the abscissas are proportional to m where m == x4/2a \ t,—that is, to the 11 See references in my report for 1903, p. 205; also Ingersoll and Zobel, Mathemat- ical theory of heat conduction, chap. vii; also E. D. Williamson and L. H. Adams, Physical Review, n. s., vol. xiv, August, 1919, p. 100. EFFECT OF LAST ICE AGE Fa Bs depth—and inversely proportional to the square root of the time, and also to the square root of the diffusivity (a?) == 203 in foot-year units. One important thing must be noted. If the temperature has risen or fluctuated in any way since the time when the original increase is sup- posed, but always kept above the assumed initial sudden change, the tem- perature will always be above the temperatures which we thus compute. Now we find that the rate of increase or temperature at (figure 2) the bottom of the mines is almost precisely the same as the rate of increase which we get by connecting, for instance, Van Orstrand’s observation (probably the most accurate we have) with a surface temperature of 32 degrees. The gradient from Van Orstrand’s temperature of 86.4 degrees at 4,900 feet to 32 degrees is 1 degree in 90 feet. Strictly, the depth should be taken from the topographic mean depth, giving more weight to the material immediately overhead; but that would probably not mean a difference in depth of over 100 feet, and the ventilation error is prob- ably as important, but more uncertain. According to Chamberlin, the gradient of 1 degree in 103 feet from the surface increased to 1 degree in 93.4 feet from 3,324 to 4,837 feet, which will make the bottom gradient just about 1 degree in 90 feet. Figure 2 shows this line and observations of all sorts compiled, and one may tell by inspection how far the statement is true. We then have this problem: To adjust the curve given by the black area of figure 2 to the excesses of temperature above the line showing the bottom gradient in figure 1 and see how large we can make the scale of abscissas. After a good deal of study to describe a method which will obtain time estimates with reasonable rapidity and with an accuracy as great as the data at present warrant, I suggest the following: Plot the observations with the temperatures as one set of ordinates and the depths as the other, as they are in figures 2 and 3. Draw a line from a point representing the temperature at the bottom, whose slope shall represent the rate of .change of temperature there per unit of depth. In figure 2 its slope is 1 degree in 90 feet. Such a line should pass near or close to the actual temperatures below 3,500 feet. Then plot to the same scale of feet the amounts by which the observed temperatures at the various depths ex- ceed those given by the line just drawn, for the same depth. This has been done in figure 1. It is clear that up to a depth of about 3,000 feet the observations do not systematically exceed the temperatures given by the line drawn. It is also clear that this line hits the tos at a tem- perature not far from that of freezing. XLVII—BULL. Grou. Soc. AmM., VoL. 34, 1922 714 «A. c. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY Then plot from the same origin a curve which is the reverse of the probability curve—that is, through the following points :'* nm = 7 ==. 000 08> 18" S36) STS" 1200 1.10 41.20 1.40 1:54" 1264 1282 aaa 91 ..80 GP 227 |) 1bT A208 705.7 08 ee These values of y represent the effect of a sudden increase of tempera- ture at a time past (¢) and at a depth such that if a? is the diffusivity (== 203 here, 400 (Kelvin) for units of foot and year) the abscissa m == (depth y)/2a\ t. Now expand this probability curve reversed up, if necessary, by in- creasing every ordinate in the same proportion so that it shall be close to the surface temperature observations at the surface. Then see how much we can stretch it to the right, increasing all the abscissas in temperatures the same ratio, and still have the observed excess lie above the curve. If we let m == 1 correspond to 4,000 feet, most of the observations will lie below the curve in figure 1, and if m = 1 corresponds to 2,000 feet, the curve lies way under the observations. The nearest fit is by letting m == 1 correspond to 3,000 feet and stretching the curve to the right about three times. Whence, using 203 for the diffusivity instead of Lord Kelvin’s 400, as it agrees better with B. O. Peirce’s tests on these very rocks, we have 1 == 3,000/(2 X 14.4 x t) . Whence we have % == 11,080 years since the rise started to spread downward. This checks well enough with recent estimates by de Geer and Antevs. It is clear that any other diffusivities or depths at which postglacial changes of climate are not yet perceptible can be readily placed in the above simple equation, which may be expressed in words as follows: The depth at which the excess of temperature, above that given by the gradient derived from temperatures too deep to be affected by postglacial warming for the said depth, is but 15.7 per cent of the excess of the sur- face temperature, is twice the square root of the diffusivity multiphed by the time since the sudden postglacial amelioration. Lord Kelvin took the diffusivity a? as==400. Other figures are given in Ingersoll and Zobel’s Appendix A, but they omit B. O. Peirce’s figures on the copper-bearing rocks,’* to wit: 12 Davis, Brenke, and Hedrick’s Calculus Tables, p. 54; Johnson’s Theory of Error, and Ingersoll and Zobel, ‘*‘Theory of Heat Conduction,” p. 144. e 18 Proceedings of the American Academy of Arts and Sciences, May, 1903, vol. XXXVI, no. 23, pp. 658 and 659. The diffusivities in ¢. g. s. units, used by B. O. Peirce. Callendar and McLeod, Inger- soll and Zobel, and physicists generally, must be multiplied by 33,800 to put them into the foot-year units used by Lord Kelvin, and by 3,153,6 to turn them into meter-year units. There is a decimal point wrong in the figures for meters on page 199 of my report for 1908. EFFECT OF LAST ICE AGE Fan SRE ai Cees (VST Eg eae ee aE Ces BRIO) JOOMMUCTIVILY : ind Gciethe ye ol ocsid =, ab. cud» .003 Co LY ps ee ee 2.82 . 0036 EU VOU vase, 0) dececaig oss elod ete ts 's 2: 6T . 0035 OE, Spee LoS SRE SR aS Terk . 0034 CGP IOIMETAEES 5s Meee vce ee 2.55 .O04T 2.64 3 . 0052 The diffusivity is the conductivity divided by the density * the spe- cific heat capacity per unit weight. This latter 1s not far from .2, but has not been determined. With due regard to the fact that the forma- tion is mainly trap and but very little amygdaloid, and still less con- glomerate, I have taken .006 as a fair value for the diffusivity in ¢. g. s. units = 203 in terms of feet and years. This value is much that which Lord Kelvin found for damp Calton Hill trap, and .0064 in c. g. s. units is quoted as an average for certain erustal rocks by Ingersoll and Zobel. It is only about half the value, 400, so often used. It is clear that it would be wrong to assume an in- flection of the curve at 4,000 feet, so that there must have been a marked amelioration of the climate since 19,600 years ago. On the other hand, if the heat wave had only gone 2,000 feet, the change would have started only 5,000 years ago. It has plainly gone farther. It looks as though there had been an era of milder climate between the present and the Ice Age, with a mean annual temperature perhaps as much as 60 degrees Fahrenheit. MATHEMATICAL DISCUSSION For shallow depths relative to the curvature of the earth the latter may be neglected, and the case may be considered one of the flow of heat in an infinite body with the temperature at different depths at the begin- ning given, and also the variation of temperature from time to time at the surface. This problem has been treated by many authors beside myself.7# ‘Among those more readily accessible than my old text-book, Rie- mann’s “Differential gleichungen,” the works of W. E. Byerly’? and Ingersoll and Zobel,*® the article by Byerly in Merriman’s Course in Higher Mathematics may be mentioned, as well as an article by Dr. T. Tamura in the Monthly Weather Review for July, 1903. It is the case stated in problem 3, on page 88 of Byerly’s work, easily solved by combining the solutions of sections 50 and 51. 14 Tn vol. vi, the annual report for 1903, and publication of the new series of the publications of the Geological Survey of Michigan, Lansing, Michigan. 1 “Wourier’s series and spherical harmonics,” articles 49-54, Ginn. 1% An introduction to the mathematical theory of heat conduction with engineering and geological applications, Ginn, 1913. 716 A.C. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY Let twas) be the temperature at a depth of (a) at a time represented by (é), and let y/ (1) Ut) = wu (zt) + U (xt)y where (2) wc issuch that w’(2.)= 0, and w’ wo) = F(¢t)—that is, is a function of the time only, at the surface, where z is 0. Also: (3) Wey 18. Such that 2” 44. — O,.amid We7 7, — a (ee (4) Then ut) will be = F(t) at the surface—that is, Wien = ee) Urzo) = f (x). But wu must also satisfy the differential equation (OS Dara Da: A value of w’’() is found in Article 50 of Byerly and of w’j that will satisfy this equation (6) as well as the conditions above (by Byerly equa- tions (6) and (7) of page 84, and (10) of page 88. Compare Ingersoll and Zobel, page 70, equation (22),) and we have: —g2 7 la gs 282 ) m=] soqavie FH st/sa)-at if —(A—2x)? (Aart —(A+2)?/4a7t tava, (. ) soya and if we replace the second part by the value given in Byerly’s equa- tion (7), page 84 and also write (5) Also (8) m=2/2avt, we have: (9) pee ee -. F (t—m?2t/B?) dB+—= Sa " f Copa dp ~ [°F (-a+ms/x) ap. If the functions F and f are known, these expressions may be expanded into strings of probability integrals of the form P 2 m Bae av i mM. Suppose, for illustration, (10) f(x) =U" (eo) = Ueos) =A +B, where we may assume that under the ice-sheet A was about 32 degrees MATHEMATICAL DISCUSSION TLE Fahrenheit and B was 1/90, then the last part of equation (9) becomes Cape ees i! : (+8 (e+-ma/2) Jap 0 —B2 ~ € (A+B (—2-+m_/a) )as. ™ We see that the A terms are equivalent to one-half of Po Pos (P cea a m)« y The B terms, taking out B, m, and x from under the integral sign, are oa) ro) —p2 Ue(reaercr ea” [)( a The last two integrals are easily solved and are zero, for we may take : 6? as the variable, and dG? is 28d8, and the limits of integration for are the same, whether 8 is m or —™m. Also P~ =1; thus all the Bx terms reduce simply to Bz, and a2) 4" =A. PA Be. If <=0 m=~ and P»n=1 and wu” (z.)A+Bz, as it should. If, now, we assume for F its simplest value and assume that (13) F(t) is simply C, a constant, say the present mean annual temperature of Calumet, (48 degrees) F(t)=C, then the first part of equation (9) becomes: (14) ib =O a) Combining equations 14 and 12, we have this result, that if uo.y=C and U(x) =A+Bzx (15) then wer =C’+(A—C)P,+ Bx. It is this formula which we have used to estimate the time since the last Ice Age, but it is only a first approximation. The expression for the rate of increase downward under the ice may, perhaps, be nearly enough covered by the expression A+ Bz, if the ice ages are reasonably long; but the expression for the surface temperature is surely not uniform. It might naturally be a periodic one with a constant temperature during the times that the region is covered with ice. A simple form on which I have done some numerical work assumes u=0°, and, starts at the middle of an Ice Age, from t=0 to t=7'/4, then lets w= sin a up to 37/4, and then =0 to T, where T is one complete period of climatic fluctuation, Such a curve might not be very far from representing the real fluc- tuation of temperature, except that the duration of the ice-cap would vary, growing less toward the margin of the ice-cap and also having 718. A. C. LANE—-GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY more or less lag after the climatic minimum in extending and after the climatic maximum in retreating. Such a curve may be represented by a series of sine terms Carneaaeey WA | uh n/2 2n f (16) w=F(t)= 5 oes (sum of terms (—1) (oan sin 2rnt/T, and if we represent F(t) by any such series of sine terms sin (2rnt/7T +1) we can get a general expression for wu’ (xt) by writing for each term e—D (sin 2nt+1—D), where D=(x/axV 7 /T as above. The resulting series are, however, not always convergent or only semi-convergent, though they are the more rapidly convergent the greater x and the less t, and I have not carried the mathematical work numerically farther, as we know so little regarding post-glacial climate fluctuations. It may be noted however, that each sine term represents an effect on the temperature which is later, and less, the deeper the point the temperature of which is studied. If we take a relatively simple assumption, we can get a closer approxi- mation to the actual readings. Assume that there was not merely a sudden jump to a temperature of C(=43 degrees), but that there is a simple sine variation of temperature added. This will bring in three new constants which we can juggle with, to wit, the amplitude of this variation (KK), the period of duration of it (7'), and the time at which it is zero (L). It is therefore no wonder if we can, by giving them certain values, get pretty good accord. If we note that the actually observed temperatures are most in excess of those obtained by the equation (15) uen=C+(A—C)P,, 4+ Br =43-+ (82-48) Px /2V 203¢-+ 1/902 tor about 1,800 feet depth, where they are about 8 degrees in excess, we can get a good approximation by assuming that the crest of the periodic wave above mentioned is now at that depth, and that it was at the surface when the ice went off. Whence we get (16) 27(11,080)/T 1800V7/2.37 +L=7/2 (17) 2n(0)/T=0V 7/2.38T +L=7/2 Eliminating from these equations, we find that this would involve a period T of about 90,000 years. Then by V an 00/7 /9.12(TO) ANG 994 / (18) Ke 1800V'7/203(T=90,000) _ 9 _ p24, VE we find that K= about 17 degrees if this is the value of T. This would imply an immediately postglacial mean temperature of OTHER CAUSES OF LOW GRADIENTS 719 about 60 degrees, growing gradually cooler to the present temperature of 48 degrees. OTHER CAUSES OF LOW GRADIENTS On page 764 of my report on the Keweenaw Series, above cited, I have listed a number of the factors in making the rate of increase of tem- perature in the copper mines relatively low, apatt from any glacial effect. Presented briefly, they are as follows: (1) Most mines have been put down where oxidation of pyrite or of coal may have increased the temperature as far down as this action went. Temperatures taken in borings for oil may also have been affected by exothermic reactions. Of such reactions there is very little trace in the copper mines. If the calcium chloride found at the bottom of the mines was derived from a chlorine-containing glass, it would be endothermic. (2) The greater the diffusivity, the less the gradient. The copper- bearing rocks, however, have not a high diffusivity, but a low one, about half the average for the earth used by Kelvin, about two-fifths that of granite, and about two-thirds that of marble. Thus the low gradient must be attributed to some other cause. (3) An imbibition of waters from above would, of course, lower the gradient. I believe that this has taken place and is an important factor, but I can not use the low gradient as a very weighty argument for such imbibition, because the low gradient might be accounted for otherwise, as we see. (4) As I have discussed in some detail, the extrusion of the great thickness of lava flows of the Keweenawan would tend to exhaust the heat beneath and make an extra thick crust, and hence a lower. gradient. There are indications of such a thicker crust which may be drawn from eravity observations, and from the theory of isostasy. (5) Not only that, but Joly in his recent book, “The Birth Time of the World,” and Arthur Holmes in his book, “Age of the Earth,’ and in articles contributed to the Geological Magazine, and others have called attention to the fact that a very substantial part of the geothermal gradient may be due to radioactive heat. So as the traps are much less radioactive than the average rocks, according to some investigations, a thickness of 30,000 feet of trap as against the same amount of granite would go a good way toward accounting for a gradient of one foot in 90 rather than one foot in 60, according to some results. The data are, however, not yet very accordant.17 “Wor references, see Clarke’s data of geochemistry. U. S. Geol. Survey Bull. No. 695, pp. 306-315. 720 «a. Cc. LANE—GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY (6) The heat of crushing and orogenic actions may very likely tend to raise the average gradient in other places, but be absent here. On the whole, I must maintain still that “the low gradient is not icon- sistent with endothermic reactions and with downward-working waters. It will probably be a long time before we shall be able to say at all defi- nitely which part of the low gradient must have been due to each factor.” This will probably come through comparative studies of the gradients in different districts. OTHER REGIONS If, however, the temperatures near the surface are higher than would be inferred from the temperatures at the bottom, and the rate of change there, and the consequent less average gradient for the whole depth, than that at the bottom are due to postglacial warming, they must not be con- fined to the Copper Country. The phenomena must be widespread, al- though the amount of warming at the surface and the depth to which the warming has penetrated should naturally vary from place to place. This is indeed the case. It would take us too far to follow it up in a paper which was started as a study of one phase of the question of copper deposition, especially as we may look for a monograph on the subject by C. EH. Van Orstrand, who is doing much more accurate work than any I have done; yet, just for illustration, we have plotted in figure 3 his ob- servations of the temperatures in the Lake well.1® It should be noted that as the rocks are quite different, and the diffusivity also different, and the well near the very edge of the farthest extension of the ice-sheet, one should not expect the size nor the depth of penetration of the post- glacial heat wave to be the same. In each case, however, there is a fairly uniform gradient near the bottom of the well. In each case this gradient points to a surface temperature near freezing. The depth of penetration of the heat wave seems somewhat greater in West Virginia, though not as much as might be expected. Since reading this paper my attention has pee called to similar facts and a similar explanation given by Prof. H. Arctowski, of Lwow (Leopol).*° The records of the deepest mine in the world, that of Saint Juan del Rey, Brazil (6,726 to 6,426 feet), also show a much more rapid rise toward the bottom.*° . 18 Darton’s U. S. Geol. Survey Bull. No. 701, p. 94, and the reports of the West Vir- ginia Survey ; also a separate pamphlet by I. C. White. 127 Kosmos, May 2, 1928. 20 Mining and Metallurgy, June, 1923, p. 2838. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 34, PP. 721-748 DECEMBER 30, 1923 CAMBRO-ORDOVICIAN SECTION NEAR MOUNT ROBSON, BRITISH COLUMBIA? BY LANCASTER D. BURLING (Presented before the Society December 28, 1921) CONTENTS Page SMM RE ACAI Voc a ce eo en a ena Sib ee Arai uti Oe Sw sw idle See 6 oa ne Haha 722 Semeranzed section, Mount Robson regione.) 2.5.2 ce cewek ee ce awe 23 Nomenclature and thickness of formations................ fae Vote 726 Included fossils and age relationships of formations...... Sramiche teins ease 726 Nomenclature of mountains. and rocks exposed in each formation.. ..... 726 Contact between the Upper Cambrian and post-Cambrian (Ordovician or a mM TTR er et es Cyt A TS lle %e ile Pe Gx cm bayrele a eras we aiaale eb w ace saree ele ee Cae Contact between the Middle and Upper Cambrian...................... 729 Contact between the Lower and Middle Cambrian...................... (29 Contact between the Lower Cambrian and pre-Cambrian............... 732 Topographic features, with details as to synonymy and stratigraphy..... 732 ee erate MCU Mb Pee PON iretaris viecc) aay aoe a wd wctla eae a Mitt Ba wae o duce Ha alate pies 732 ae at TUNE Tee, ee oat Se ead woke Shake ete weeks Sek & sia dig wo Sibgwe ee cd (32, CT in LEUVE a pews ae Rae ie Ae ad ora Pe ae ae Some tm ahora Riots 732 Hota’ clits.c... ee ae ee ee SEP eo ES OLA Se eed RPO ne 733 2 TLE ALEVE Sage Spa Ip Pe pg 733 ee MOI TGS RIMM IAN eianis ea cS wiela ee. Sd Ces Sin oe eis Sew ee we cee ache nce 733 OEESTEET: [ECB a yh ee ae 2 aad ante ly ene a ee a Ss rh er ce leh Pe a te San IV ROMPTTU ALITY 4.0 eee teifal ele! 2e ooh alle ie vie oie wake elece ee Se Ob oe wea el 734 NEVE DEES VIE Te Ts GRD ed Sen Mee pcp meats Fir ena ace on 734 SUR IPOEMMENOMNSOTT St rene oi. ac ucirag ches ae ei 1s. e Crake eae ele SUN RIES Ui bie we bo deuce ae 734 REMMI RA DERM CIENT ae ler a rn Ge at Rec te niece bee Sa wie Siete w oie ele a’e viele 735 Ee IRE Lee TR clara ate ahaj dalle Sas dace Se wR aU OLE wee Be ie Ae A ee 735 DES Sh LE SST OR eer teen eee ae ht ek ea re SEEGER MSH ona Sees Tah 735 Geologie formations, with details as to synonymy and stratigraphy...... 736 “TE, TDS CHS SS Porn SE eee io este ett ee 736 RN aA TCTAN AUST OER eee Pee Wale tec ayec, «a's s,s Chas cori e elpiehet seve ave sew nice e Rkees owe 737 RAINE IN IC EMTS OS HOMIES 2 err mie rae co ea taie Ge, chee Simei eieis Oe a elae'e St we Sm wine weal 738 SU ORDER WTAE ESO Eo in sen) ok area kn: fae he ck Miami wie aig sta wigorm B/S Dub nisve ws 739 eee RL UNIRINPLCN TIL Fe ee ect ne een N Gnecealalitla Getia ew Dalek Wins c's ma bade aes 740 BEET IHESTONES ...66s.s ~ sfe ct elk hee es Sie! ai ce meiele eME Na avg i 0% Wath oat od coor tie 740 Bese MES OTICS ss eae sc ivlad pis «60s oe wha wae mee sees ibleie ava sr a sete 741 1 Manuscript received by the Secretary of the Society September 9, 1922. (721) 722. i: D. BURLING CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON Page Adoiphus. (“Hoia”) ‘limestone... oo = ee ee ee n Sistem oa ae eee Mahto * sangstanes: ;..653- oo. Soe eae oe eee ee ee eats a2 elem 745 Moral (“fah” } limestone “formalions:: - 2. vice. ee FRO ee oa ee MeNauahton: SandsStones oie 2220 See Se eee eee So aia eee rene 746 Mietie sandstones: 5.0 2 Be re ee ae See SA eee st InrTropUcTION (§ 1) McEvoy? was the first geologist to describe the succession near Yellow- head Pass, between British Columbia and Alberta, on the line of the Grand Trunk Pacific Railway. He applied McConnell’s* terms, Bow River and Castle Mountain, to the clastic lower and the calcareous upper portions respectively, mapping Mount Robson itself as Castle Mountain. Walcott has published two papers on the geology.* These papers are extensively referred to in the following pages, but this is the proper place to record my regret at having to present an interpretation of the stratig- raphy so widely different from that of Mr. Walcott. It is unfortunate that conclusions so diverse from those that have preceded them should be based on field work so incidental as my own, and I should hesitate to present the results of a few days’ reconnaissance in an area where another has done several seasons’ work if my evidence were not extensive. The differences between the two interprtations of the sections involve so many points that the general reader who pays too close attention to the descriptions of formations or individual mountains may become con- fused. For such there is presented a generalized section giving Walcott’s interpretation and my own (§ 2), and three tabular correlation tables: the nomenclature and thickness of the formations (§ 3).; the included fossils and the age relationships of the formations (§ +) : and the nomen- clature of the mountains and the rocks exposed in each formation (§ 5). The paper throws new light on the stratigraphy and paleontology of a most interesting section of the lowermost Paleozoic, and its details are essential to the future worker who may wish to use the area as a key for exploratory work in the neighboring regions, because some of the forma- tions, stated by Walcott to be typically exposed in certain mountains, are entirely absent from them (Mounts Mumm and Rearguard, for exam- 2 Ann. Rept. Geol. Surv. Canada for 1898, vol. xi, 1901, Part D. 2 Idem for 1886, Part D, 1887, pp. 29D-30D. New Lower Cambrian subfauna: Smithsonian Misc. Coll.. vol. 57, no. 11, 1913, pp. 309-326, pls. 50-54 (published July 21). Cambrian formations of the Robson Peak district, British Columbia and Alberta, Canada. Idem, vol. 57, no. 12, 1913, pp. 327-343, pls. 55-59 (published July 24). GENERALIZED SECTION ord ( 23 ple), and because these mountains are those closest to and most easily climbed from the usual camp, at the foot of Robson Glacier. For this reason the writer feels that he should not postpone publication until the faunas can be worked up. GENERALIZED SecTION, Mount Rosson ReEetion (§ 2) WALCOTT ORDOVICIAN : Robson limestones (§ 23).... Massive and _ thin-bedded limestones, partly arena- ceous and dolomitic. Fossils: ‘‘Near the base” (from the Extinguisher), “where there is a com- mingling of Upper Cam- brian and Ordovician mpes «(8 236) 5 “also higher up” (drift blocks in a moraine), “where numerous Lingule of Or- dovician oceur” (§ 230). Wore Orgoevician: ... 6s... ke vs characteristics © UPPER CAMBRIAN: Lyng limestones (§ 24)..... Thin-bedded gray and blu- ish gray limestone with bands of shale. Fossils: None. Dorval Upper: Cambrian........ 2AOO-| Total Uppers Cambrian)... 2: BURLING ORDOVICIAN : The Robson limestones are not known to be present in the Mount Robson re- gion (§ 23d), the top of Mount Robson appearing to lie at or very close to the horizon of the Ex- tinguisher fauna instead of 3,000 feet above it. There is a thin-bedded se- ries of shales and_ in- traformational conglom- erates, carrying Ordo- vician fossils, above the top of the Lynx forma- tion. These are exposed in the Extinguisher and in the summit of Mount Rearguard, where they are.cut off by erosion 375 feet above the base. They are unnamed in this paper (§ 23f). S000s LOtal Ordoveran sf .e 8 oie elem oho UPPER CAMBRIAN: LNs KOPN CEO! CSA) ee sek More or .2ss thin and ir- regularly bedded _ series of limestones and shales, marked at the base by ripple-marks, mud-cracks, and casts of salt crystals. Thickness obtained in Mounts Lynx and Rear- guard (§§ 14, 18, 24). Fossils: Abundant and in a score or more horizons. Feet 724 LL.D. BURLING—CAMBRO-ORDOVICIAN NEAR MIDDLE CAMBRIAN : Titkana limestones: (§ 25)... Massive beds of thin layers of bluish gray limestone with bands of dolomitic limestone. Thickness in Mounts Tit- kana and Rearguard | (§ 25a). Fossils: An upper horizon comparable with the Ste- phen and a lower hori- zon 1,000 feet below (§ 25a). MM umm limestones (§ 26).... Massive-bedded gray are- naceous limestone. Thickness estimated from an exposure of the “Hota” in Mumm Peak (§§ 26b, 300). Fossils : None. Hitka formation (§ 27)..2... Alternating bands of thin layers of arenaceous lime- stones and shales. Thickness estimated from an exposure of the Tit- ‘kana in Mount Hitka (S200): Fossils: None. Tatay limestones (§28)..... Massive-bedded gray are- naceous limestone. Thickness obtained in Tatei cliff. Fossils: None. MIDDLE CAMBRIAN: Titkana limestones (§ 25)... More or less thin-bedded usually dark-colored lime- stones with bands of shale and beds of dolomitic limestone. — Thickness in Titkana Peak (§§ 18, 24d, 25a). Fossils: Abundant and in a score or more of hori- zons, including the upper one of Walcott, which oc- curs 600 feet above the base of the formation, and the lower one, which occurs at the base of the formation (§ 25a). Not present in the section. The formation was de- seribed from an exposure of the “Hota” (§§ 30), 309, 32c), but was as- signed to a position in the section which made it and the Tatei synony- mous. The latter name has been accepted for the formation (§ 28b). Not present in the section. The Hitka and the Tit- kana are synonymous and the latter term has been accepted (§ 25b). Tatet limestones (§28)..... More or less massive blue to blue gray limestones, 1,000 feet being exposed beneath TitKana above Lake Adolphus and 900 feet in Tatei cliff, but upper and lower bound- aries uncertain, because Walcott’s description is general and does not re- cord fossils. Fossils: Frequent, several lots being secured, but less fossiliferous than underlying Chetang or overlying Titkana. MOUNT ROBSON Feet 2,550 1,000 GENERALIZED SECTION Feet Chetang limestones (§ 29)... 900 Bluish gray thin - bedded limestones. Thickness in Chetang cliff. Fossils: An upper horizon and a lower 250 feet be- low, with Atbertella. Total Middle Cambrian....... 6,200 Lower-Middle Cam- brian boundary Walcott (§ 8a). LOWER CAMBRIAN : Hota formation (§30)...... Gray arenaceous limestones and siliceous shales al- ternating with massive quartzitic sandstones. Thickness obtained from an exposure of the “Tah” in Mumm Peak, near Mural glacier, and lith- ology is descriptive of the lah?’ (§ 30d) . Fossils: Walcott (personal communication) states that the “new Lower Cambrian subfauna” with Olenellus was referred by error to the Mahto and belongs here (see § 32d and note opposite). Mahto sandstones (§81).... Massive - bedded quartzitic sandstones with bands of siliceous shale. 1,800 Fossils: None (page 339 of Walcott). (See footnote in § 81c.) Chetang limestones (§ 29)... Thin-bedded blue limestones with some shales. Thickness in Chetang cliff. Fossils: Abundant in many horizons. Albertella was found in Chetang cliff, and in several horizons on Mural Brook, and in the summit of Mumm Peak (§ 29D). Adolphus limestone (§ 30)... Gray arenaceous limestone, changing on the strike, near the base, to thin- bedded blue-black lime- stones. Thickness obtained in Mumm Peak (§§ 30f, 30g, B22) Fossils: Well-defined Mid- dle Cambrian fossils were found at two horizons in the thin-bedded lime- stones at the base of the Adolphus. The “new Lower Cambrian subfauna” of Walcott does not occur in the Adolphus (‘‘Hota’’), but in the “Tah” (see § 32e). Total Middle Cambrian......... Lower-Middle Cam- brian boundary, Burling (§ 8). LOWER CAMBRIAN: Mahto sandstones (§31).... Comparatively thin-bedded quartzitic sandstones with purplish sandy shales. Thickness estimated in Mumm Peak (§ 31d). Fossils: I first placed the ‘new Lower Cambrian subfauna” with Olenel- lus and Pedeumias here (§ 82d), but as the bound- ary is now drawn that fauna belongs with the “Tah. No other fossils found. 725 Feet 950 400 1,200 726 LL.D. BURLING—-CAMBRO-ORDC VICIAN NEAR MOUNT ROBSON Feet Feet Tah formation (§ 32)......:> 800 Mural limestone formation Siliceous shale and _ inter- Bs A Nr a ee aE ee 1,000 bedded siliceous lime- Massive arenaceous' lime- stones. stones with interbedded shales and quartzitic sandstones. Thickness in Mumm Peak. Thickness in Tah Peak. Fossils: Abundant at many Fossils: None. horizons, the “new Lower Cambrian subfauna”’ oc- curring 550 feet below top (§ 32e). McNaughton sandstones...... 500 Unnamed sandstones (§ 33).. 400 Thickness in Yellowhead Thickness in Mumm Peak, Pass (§ 33). base concealed. Fossils: None. Fossils: None. Total Lower Cambrian........ 3,900 | ‘otal Lower Cambrian........ 2,600 PRE-CAMBRIAN: Miette sandstones (§ 34).... 2,000 *RE-CA MBRIAN : Total. Campnag..0 oi 3 tele 12,200 | ‘otal. Cambrian: (2%... S22. eee 12.500 | | Not studied. NOMENCLATURE AND THICKNESS OF FoRMATIONS (§ 3) Mr. Walcott described twelve formations in his papers on the Mount Robson region—ten from the region itself, one from the McNaughton Mountains, and one from the Miette River. Because of duplications and changes in the interpretation of the stratigraphy in some of the moun- tains, it has been necessary to reduce the number of these formations to seven. The changes which have been required are expressed in the fol- lowing table, in which there are sectional referencs to the detailed ex- planations which occur in the text. The formations are listed in strati- graphic order, reading from the top down (Table 1). INcLUDED Fossits AND AGE RELATIONSHIPS OF FORMATIONS (§ 4) The main differences in the formations and fossil horizons listed by Walcott and the writer are (a) the discovery of thin-bedded Ordovician limestones and shales above the Lynx instead of the Robson limestones, and (b) the reference of the New Lower Cambrian subfauna, a horizon referred by Walcott to the “Hota,” but found by the writer in the “Tah” (Table 2). NOMENCLATURE OF MOUNTAINS AND ROCKS EXPOSED IN EACH FORMATION (§ 5) Mr. Walcott has made several changes in or additions to the names applied to the topographic features of the Mount Robson region by the Formation name (Walcott) .* Robson limestones (above Extin- guisher fauna). Lynx limestones (below Extin- guisher fauna). Titkana limestones. Mumm limestones. Hitka formation. Tatay limestones. Chetang limestones. Hota formation. Mahto sandstones. Tah formation. McNaughton sand- stones. | * Names in stratigraphic ol ‘ Tarte 1 Formation name (Walcott) .* Remarks. Robson limestones (above BPxtin- guisher fauna). Lynx limestones (below Pxtin- guisher fauna). Apparently absent from Mount Robson region ($§ 23d and 23e). Greatly enlarged by finding 38,000 feet of additional strata between the top of Walcott’s Lynx and the Dxtinguisher fauna. Accepted formation name (Burling). Estimated thickness (Walcott). Measured thickness (Burling). Unnamed (§ 23f). Lynx formation (below Bxtin- guisher fauna). Titkana limestones. Titkana limestone. Mumm limestones. Hitka formation. Tatay limestones. Described and named from an exposure of the ‘‘Hota,” which is now called Adol- phus (§§ 260, 300, 32c). (Absent. ) 3,000 feet in Mount Robson. 2,100 feet in “Lynx Mountain” (§ 14). 2,200 feet in Mount Titkana. 600 feet in Mumm Peak. 375 feet of Ordovician shales and thin-bedded limestones occur above Wxtinguisher fauna in Mount Rearguard (§ 287). 5,000 feet in the real Mount Lynx and in Mount Rear- guard. 2,500 feet in Mount Titkana. It does not occur in Mumm Peak (§§16 and 32c). Merely a duplication of the Titkana (§ 250). (Absent. ) 1,700 feet in Mount Hitka. Spelling changed to Tatei by Canadian Geographic Board (§ 21). Tatei limestones. 800 feet in Tatay cliff. Tt is the Titkana which oc- eurs in Mount Hitka ($270). 1,000 feet in Mount Titkana and Tatei cliff. Chetang limestones. Chetang limestones. Hota formation. Confused (stratigraphy, fos- sils, localities, and mode of occurrence) with the “Tah,” the Mahto, and the “Mumm” (§ 30). Mahto sandstones. Adolphus limestone (§ 309). 900 feet in Chetang cliff. 950 feet in Chetang cliff and in the top of Mumm Peak. 800 feet in Hota cliff. 400 feet. below the Chetang, in the top of Mumm Peak. Mahto sandstones. 1,800 feet in Mahto Mountain. 1,200 feet (estimated) in Mumm Peak. Tah formation. Confused (stratigraphy, fos- sils, localities, and mode of occurrence) with the “Hota,” the Mahto, and the “Mumm” (§ 32). Mural limestone (§ 329). s00 feet in Tah Mountain. 1,000 feet in Mumm Peak. McNaughton sand- stones. Left unnamed in Mount Rob- son region (§ 330). Unnamed (§ 830). 500 feet in Mc Naughton Moun- tains. 400 feet in Mumm Peak, base not exposed. * Names in stratigraphic order, youngest at the top. ; PA TKK BT "3 ey etek ; ors shed nat » ‘i: ter ete rhein ‘Shhh peor Noe nte COAG) ie Hs ae ha Mink. | ee akan iy rr mt i rd et bar tearel | sisal | »sahaniaen » a oe he Tae B hy p Heats Cone Wirt oy (OR, tise instar ralaome sap peasant Mlb] wi Doman AOE E) wolyen i ° —— EO Formation | (Walcott). Robson limestones. | Drift an¢ gui ($. Lynx limestones. N one ee so Titkana limestones. | An | p | lo Mumm limestones. None Hitka formation. None Tatay limestones. None Chetang limestones. | An low Hota formation. The . Ca fal 30¢ Mahto sandstones. None Tah formation. None McNaughton sand- | None stones. “ ie , eM - j A , i wv rp dy vt out . | q } zt ‘ ry » 7 | a nar aa se TABLE 2 Formation Fossils Age Formation Fossils Age (Walcott). (Walcott). (Walcott). (Burling). (Burling). (Burling). Robson limestones. | Drift fossils (§ 23b) | Ordovician. Unnamed series, | 4horizons. Ordovician. and the Extin- shales and thin- guisher fauna bedded limestones (§ 28e). overlying the Lynx (§ 23f). Lynx limestones. None. Upper Cambrian. Lynx formation. 25 horizons. Upper Cambrian. Titkana limestones. | An upper (Ste-| Middle Cambrian. Titkana limestones. |17 horizons above | Middle Cambrian. phen) and a the Stephen, 4 lower. below. Mumm limestones. None. Middle Cambrian. Synonym of the|Absent from the/Absent from the Tatei (§ 260). section. section. Hitka formation. None. Middle Cambrian. Synonym of the}]Absent from thej|Absent from the Titkana (§ 27D). section. section. atay limestones. None. Middle Cambrian. Tatei limestone 4 horizons. Middle Cambrian. (§ 21). Chetang limestones. | An upper and a/| Middle Cambrian. Chetang limestone. |8 horizons aboye| Middle Cambrian. ° lower (Albertella). the Albertella zone, 3 in it, and 2 below. Hota formation. The “New Lower| Lower Cambrian} Adolphuslimestone |2 horizons, both} Middle Cambrian. Cambrian sub- (§§ 8a and 30e). (§ 309). near the base. fauna’ (§§ 380e, 80d, 32b, 32c). Mahto sandstones. None. Lower Cambrian. Mahto sandstones. None. Lower Cambrian (§§ 8b, 30e). Tah formation. None. Lower Cambrian. Mural limestone 4 horizons, includ-|} Lower Cambrian. (§ 329). ing the horizon of the “New Lower Cambrian subfauna,’ 750 feet below top (§§ 320 to 32e). MeNaughton sand- None. Lower Cambrian. Unnamed (§ 330). None. Lower Cambrian. stones, nee oe a et nt herp ome Let Si. qe eh, | jo Dak aond * hell adit teh stoma ge nae ere! Sea made | t Yl ey Lalit hee = 1m alot i mtg i yi 3 a . at : va) wn rom sist mack} ; f ree ia i MR ine st) ae : es an ae | beigth j . | ; A ble ee t sie Vicia nile Oe ee wot AS. i 2008 Nv!) Sh pir | zs AO | Shee ee) ee Tavern, Cyr ie Sey: Co tania pe eke ighiewe ah gh! 0 AG A Me be Oe bane mast edhe © : fbb is iy + he hesibewi enue 1h we a 1 = i ag VAAN NN YE Pa Waa | empl Pan povmrtg tele py egtegh Le (diy shite othe dlesney q\edammonnsah fh Alvi elite alate beilal SS Usual geographic name, The Extinguisher. (Unnamed. ) % Unnamed. ) (Un 1amed.) Mount Rearguard. (Unnamed. ) (Unnamed. ) (Unnamed. ) Mumm Peak. Lynx Center. Lynx Mountain. Mount Robson. Moose Pass Station. (Unnamed. ) Ptarmigan Peak. Walcott! range i Billings’ Chetang Mount H Hota cli Tyatungé “Lynx M Mahto M | McNaugt tains. Mumm P Phillips | in tex Phillips in leg Robson Tah Mo Tatay cli Titkana wor ah aT oo oe (ee, ae TABLE 3 Usual geographic name. Walcott’s name, ar- ranged alphabet- ically. Accepted name, Formations exposed (Walcott), named in order, the young- est first. The Extinguisher. Billings’ Butte. The Extinguisher. The Extinguisher fauna (§ 23¢). (Unnamed.) Chetang cliff. Chetang cliff. Chetang limestones. i Unnamed. ) Mount Hitka. Mumm, Hitka, and Tatay. (Un 1amed.) Hota cliff. Formations exposed (Burling), named in order, the young- est first. Hota formation (superseded by Adolphus limestone, (§ 309). Mount Rearguard. Tyatunga Mountain. Mount Rearguard. Titkana. Lynx formation (§ 14). The Hxtinguisher fauna (§§ 6a, 11, 14, and 23f). Chetang limestones. Lynx, Titkana, Tatei, and Chetang (§ 12). Upper and lower contacts not shown. These are ex- posed in Mumm Peak (§§ 13, 16). Wxtinguisher fauna (at top) underlain by Lynx forma- tion to exposed base (§ 18). (Unnamed. ) “Lynx Mountain.” Still unnamed (§§ 14 and 17). (Unnamed. ) Mahto Mountain. Mahto Mountain. Mahto sandstones. Unknown (see §14, last paragraph). Upper and lower contacts with fossiliferous forma- tions shown in Mumm Peak. (Unnamed. ) MeNaughton Moun- tains. Mumm Peak. Mumm Peak. Mumm Peak. Lynx Center. Phillips Mountain in text ($17). McNaughton sandstones. Not visited (§ 33). Titkana, Mumm (typically), Hitka, Tatay, Chetang, and Hota (§ 16). Lynx Mountain. Phillips Mountain in legend (§ 17). Lynx Mountain. Mount Robson. Robson Peak. Mount Robson. Lynx limestones. Chetang, “Hota” (Adolphus), Mahto, “Tah” (Mural), and unnamed basal sand- stones (§§ 309 and 32c). Lynx formation in part (§$§ 11, 240, and 24d). Robson limestone (3,000 feet) forming top, with Extinguisher fauna below (§ 23a). Moose Pass Station. Tah Mountain. (Unnamed.) Ptarmigan Peak. Tatay cliff. Titkana Peak. Tatei cliff. Titkana Peak. Tah formation. Probably Lynx formation (5,000 feet), with Dxtin- guisher fauna at or near top (§ 23d). Mural limestone supersedes this (§ 329). Tatay limestone. Tatei limestone (§ 28d). Titkana and Mumm. Titkana and Tatei (§ 22). tank a beh eee ohstartadd | Lath Us A 1. Sean: Oe ne Raw Saat "BL E) nodtadanobeainu bbe eyy 2 pte ‘he iit J } titel: rs rey ies Ot appt mre Pe iw REL), | f : ARE apmafeyuarin mammal adalat imate veciomadbeeetey oe Qe, alone: 9600961 PA, Sb, teed Cet) } fn catenden iiiealh eae ed Ai senha ae . eras ganibaesyagelis caps seamentiny ye rey henna ate Sal ame TORL nf eondaalaeoo nt Tom naps leita Raven t gtsigl ami i eo a ' 7 ah, “ar toma ieee Aye Reta tomm a2 hy cts three AMT a ey | po : images ee ae) ro . i Wau eM my evbnoerionyte | try ee ee perepreaiharretn inp eare-rrerene visi -wton mie Oo a a va ddl Rae a seiihettiognteli «Shi y, hte hie 1). 6 ‘grant - ome siemens me ENN tag sate nena edhe ami Hacc Ty et (Loe airasiiT: Asot andl ilt sy fp lips’ reg HE emer AE ym AD med le ati beth lng A WANA glo ye ae on wr dhe aI ero eon Ie | Eee yy) ee @ samy P FOr NOMENCLATURE ioe earlier explorers. For such of these as are concerned in the study of the geology, the following table is prepared. ‘The differences between the formations stated by Walcott as occurring in a mountain and the forma- tions found there are not due to varying interpretations of the same strata, but to the fact that Mr. Walcott did not allow for possible fault- ing between adjacent mountains in making visual correlations. (Mounts Titkana and Rearguard, for example), or did not allow enough where the faulting is evident (Mounts Hitka and Mumm, for example) (Table 3). CONTACT BETWEEN THE Upper CAMBRIAN® AND POST-CAMBRIAN (ORDOVICIAN OR DEVONIAN) (§ 6) (§ 6a.) According to Walcott (page 336 of his paper), “there is no known well-defined lithological break between the Ordovician and the Cambrian” in the Mount Robson region. He draws the line tentatively in the isolated series of thin-bedded and shaly limestones exposed in the Extinguisher (“Billings Butte’), “where there is a commingling of the Lower Ordovician and the Upper Cambrian faunas.” This fauna has since been discovered in place in the summit of Mount Rearguard (§§ 18 and 237), and evidences of disconformity have been observed at the hne where the Cambro-Ordovician boundary is now drawn. ‘The break in the section does not appear to be so important as that between the Middle and Upper Cambrian (§ 7), but it should be mentioned that the Ordovician, as here used, appears to include the Ozarkian of Ulrich, and that we have in our fossil collections many fossil horizons from the beds immediately above and below the boundary as we have drawn it. (§ 6b.) The contact between the Cambrian and the Ordovician seemed so important, and the new light obtained on the problem from widely separated districts of the Cordilleran region by the writer was so exten- sive, that when the first draft of this paper was written he expected to postpone that general subject to a separate publication. The collections are not now available to him in his peregrinations, but it will be of inter- est to students to know that the boundary between the Upper Cambrian and the overlying rocks in both the Canadian Pacific Railway section and the Grand Trunk Railway section exhibits certain remarkable features. (§ 6c.) As was announced in 1916,° there is a large area in which the relations of the Upper Cambrian and early Ordovician to the Devonian are those of angular conformity, and the detection of the line is so diffi- cult that geologists have united into one group the rocks above and below. ° The discussion includes a consideration of the Ozarkian. ‘Summary Rept. Geol. Surv. Canada for 1915, p. 98, 1916. 728 LL.D. BURLING—CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON The Devonian has been found to lie disconformably on the Cambrian or early Ordovician rocks in Roche Miette, west of Jasper, Alberta;’ in North Kootenay Pass, south of Crowsnest Pass, between British Colum- bia and Alberta;$ near Elko, west of Fernie, British Columbia;° on Beaver Creek, northeast of Helena, Montana;'® in the Sawback Range west of Banff, Alberta; in the mountains at the east end of Lake Minne- wanka, north of Banff, Alberta; in the mountains at the head of Upper Columbia Lake, south of Golden, British Columbia, and elsewhere. A survey of these various occurrences leads to the following conception of the relations. In the Canadian Pacific Railway section it appears that where the Upper Cambrian is thick and characterized by what we might call the accepted type of Upper Cambrian fauna it passes up into the true Ordovician (Black River, Trenton, and Richmond) without known > passage through the Ozarkian fauna, but that where the Upper Cambrian is thin and characterized by an Ozarkian fauna it is overlain directly and without angular uncontormity, sometimes even without easily ob- servable disconformity, by the Devonian. The latter condition of affairs is, however, characteristic only of the eastern margin of the Rocky Moun- tain belt, though it persists along this eastern margin from Roche Miette on the north almost to the International Boundary, a distance of 335 miles. (§ 6d.) In the Mount Robson region, central with respect to the entire Rocky Mountain belt, the Upper Cambrian is fairly thick, but passes: upward into rocks carrying faunas comparable with certain phases of the Ozarkian. On the eastern edge of this portion of the Rocky Mountain belt, however, the Upper Cambrian of Roche Miette is thin, carries Ozarkian faunas, and is overlain directly by the Devonian, as it is in the Sawback Range and in the vicinity of Lake Minnewanka, on the Cana- dian Pacific 200 miles to the south. If the analogy between the two sections (Canadian Pacific and Grand Trunk Pacific) holds and we are right in the generalization which we have made for the Canadian Pacific Railway section, we might expect to find true Ordovician in the fairly central Mount Robson region. The presence of apparently Ozarkian types near Mount Robson, where the rocks are surprisingly fossiliferous, might on the other hand lead us to suppose that our generalization needs certain modifications, and that we may have merely overlooked the Ozarkian faunas in our collecting from the thick but relatively less fos- 7 Dowling: Summary Rept. Geol. Surv. Canada for 1911, pp. 205-208, 1912. 8 Adams: Discovery of phosphate of lime in the Rocky Mountains (of Canada). Commission of Conservation, Canada, 1915, p. 18. 9 Schofield: Summary Rept. Geol. Surv. Canada for 1913, pp. 131-132, 1914. 10 Walcott: Smithsonian Misc. Coll., vol. 64, 1916, p. 271. CONTACT BETWEEN UPPER AND POST-CAMBRIAN 729 siliferous sections of the Upper Cambrian in the Rocky Mountain geo- syncline to the south. But the future student should not be surprised if he finds the Devonian resting on the semi-Ozarkic faunas which imme- diately overlie the Lynx formation in the Mount Robson region, and this might even happen in the summit of Mount Robson itself. The problems involved are very interesting, and the rocks may prove even more generous to the student who shall make more than a rapid reconnaissance in this fossiliferous region. CONTACT BETWEEN THE MIppDLE AND UppEer CAMBRIAN (§ 7) Walcott draws the line between the Middle and Upper Cambrian at the base of the “unfossiliferous’” Lynx limestones and above the Titkana lhmestones, in which he found a fauna comparable with that of the Ste- phen formation. The discovery of many other fossil horizons in the 1,600 feet which separate the Stephen faunal horizon of the Titkana from the Lynx, together with abundant fossils in a dozen or more hori- zons in the Lynx formation, has shown the author the faunal correctness of the separation, and the writer has already described™* the lithological and stratigraphical grounds which confirm the presence at this point in the section of a break similar in character and magnitude to the break between the Middle and Upper Cambrian in the Canadian Pacific Rail- way section 200 miles to the south. In each section the upper layers of the Middle Cambrian exhibit the downwarping which has been ascribed by the writer to peculiar conditions of subaérial desiccation, and the lower layers of the Upper Cambrian exhibit mud-crack, ripple-mark, cast-of-salt crystal, and other shallow-water sedimentation phenomena. CONTACT BETWEEN THE LOWER AND MippLeE Camprian (§ 8) ($ 8a.) Walcott places the boundary between the Lower and Middle Cambrian between the “Hota” and the Chetang, the former described as carrying the “new Lower Cambrian subfauna” with Olenellus, the latter as carrying Albertella. The lowest fossil horizon secured by Walcott in the Chetang is 550 feet above the base of the formation in Chetang cliff, and evidence is pre- sented, in the discussion of the “Hota,” Mahto, and “Tah” formations ‘ “4 Shallow-water deposition in the Cambrian of the Canadian Cordillera. Ottawa Nat., vol. 29, 1915, pp. 87-88. Notes on the stratigraphy of the Rocky Mountains, British Columbia and Alberta. Summary Rept. Geol. Surv. Canada for 1915, p. 99, 1916. Downwarping along joint planes at the close of the Niagaran and Acadian. Journ. Geol., vol. 25, 1917, pp. 145-149. XLVIII—BuLL. Grou. Soc. AM., Vou. 34, 1922 730 L. D. BURLING-——-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON ($$ 30c-d, 31a, 32b-e) to show that the “new Lower Cambrian subfauna” with Olenellus, referred by Walcott to the “Hota,” occurs in the “Tah,” nearly 1,750 feet below the base of the Hota, and therefore more than 2,250 feet below Albertella. Since we have discovered typical Middle Cambrian fossils in the basal layers of the “Hota” or its immediately underlying calcareous beds, we are free to feel a reasonable doubt as to the presence of Olenellus in the “Hota.” ($ 8b.) We have, therefore, no alternative but to draw the line between the Lower and the Middle Cambrian below the “Hota.” Just where to draw it below the “Hota” is, however, a little more difficult (§§ 30f, 3ic, 32d-e), for, curiously enough, the immediately underlying clastic series does not yield Olenellus as it does in the Canadian Pacific Railway sec- tion. Here—that is, in the Mount Robson region—the first beds resem- bling the 20-foot bed of limestone which has been described?” as forming the top of the Lower Cambrian in the Canadian Pacific section are those of a bed approximately 2,000 feet below the base of the “Hota,” in the Mumm Peak (north face). section. The highest Lower Cambrian horizon secured by ourselves from the beds underlying the “Hota” is separated from that Middle Cambrian formation by some 1,500 feet of quartzites and arenaceous limestones, and on paleontologic grounds the line between the Lower and the Middle Cambrian merely lies somewhere between. From a stratigraphic standpoint, and in the absence of any evidence of unconformity below, the line appears to be correctly drawn at the top of this quartzite series; and, since the top of the Mahto was also drawn at the top of the quartzitic series, the top of the Lower Cambrian and the top of the Mahto coincide. (See §§ 30 and 31.) In the Mount Robson region, therefore, an apparently unfossiliferous dominantly quartzitic series approximately 1,500 feet thick separates the . highest Olenellus fauna from known Middle Cambrian; and, while we have placed these rocks in the Lower Cambrian, it will be worth while to contrast and compare the section with those in other portions of the Cordillera. ($ 8c.) Known Middle Cambrian lmestones somewhat abruptly over- lie unfossiliferous quartzites in the Stansbury Range, Simpson Range, Beaver River Range (Cricket Spring), and House Range sections of Utah (first group). In the Onaqui Range, Blacksmith Fork Canyon, East Fork Canyon, Geneva, Wasatch Canyon, and Promontory Point sections (second group), however, there appears to be an almost imper- ceptible gradation between the quartzites and the limestones; and, since the underlying quartzites in a section (Mill Canyon, Idaho) closely re- 2 Burling: Museum Bull., Geol. Surv. Canada, no. 2, 1914, pp. 106 and 115. CONTACT BETWEEN LOWER AND MIDDLE CAMBRIAN ho lated to the second group have yielded true Middle Cambrian fossils, the quartzites in the second group of sections have all been tentatively re- ferred to the Middle Cambrian.’* The succession in the Mount Robson region is abrupt, however, and more nearly resembles that in the first group of sections named. The underlying quartzites in all the sections of this group have so far proven unfossiliferous; but, since Olenellus has been collected from the upper part of the quartzitic series in the closely related southern Wasatch Range (Big Cottonwood) section and in the Oquirrh and Pioche sections, the quartzites in these, as well as those in the first group of sections, and in the Mount Robson region, are referred to the Lower Cambrian. ($ 8d.) In the Canadian Pacific Railway section it has not been so much a question of where to draw the line in an unfossiliferous interval as of where to draw the line in a very fossiliferous series where scattered fragments of Olenellus have been identified from horizons well above the basal clastics. Such occurrences have been ascribed by the writer to recurrence, and the discovery of the presence at the top of these clastics of a diastrophic break of considerable magnitude** seems to confirm this delineation of the Lower-Middle Cambrian boundary. Walcott does not accept recurrence as an explanation and minimizes the stratigraphic im- portance of the unconformity at the base of the Mount Whyte, placing’ the boundary at the top of the Mount Whyte, well above any possible occurrence of Olenellus. A recent textbook’® even makes the statement: “Tt should be made clear that the genus Olenellus became extinct before the Middle Cambrian strata were deposited,” and calls it one of the prin- ciples laid down as a basis for the subdivision of the Cambrian system. But we are coming to realize that the sudden introduction of new forms is of far more importance than the ultimate extinction of the old, and that in the delimitation of stratigraphic boundaries we must substitute the proper valuation of a debatable series of diastrophic and organic phenomena for a simple yes or no. ($ 8e.) In the Mount Robson region it is more nearly possible to use . the shorter method; but even here the drawing of the Lower-Middle Cambrian boundary involves placing it somewhere in an unfossiliferous 1,200-foot quartzite series (Mahto) which separates known Lower Cam- brian limestones (“Tah” == Mural) below from known Middle Cambrian limestones (“Hota’ == Adolphus) above. We have given our reasons for 18 Burling: Museum Bull., Geol. Survey Canada, no. 2, 1914, p. 110. 144Summ. Rept. Geol. Surv. Canada for 1915, p. 100, 1916. .& Smithsonian Mise. Coll., vol. 67, no. 3, 1917, pp. 61-67. 16 Miller: Historical Geology, 1916, p. 57. 732 L.D. BURLING—-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON choosing to draw it at the top, where the change from sandstone to lime- stone forming conditions is fairly abrupt, rather than at the more or less transitional calcareous to arenaceous boundary at the base of the Mahto. CoNTACT BETWEEN THE LoweER CAMBRIAN AND PRE-CAMBRIAN (§ 9) The contact of the Lower Cambrian sandstones with the pre-Cambrian rocks in the Robson district is described by Walcott (pages 329-330) as finely shown “to the north, west, south, and southwest of Yellowhead Pass, in Mount McEvoy (Mount Toot Toot), and Yellowhead Mountain, Mount Fitzwilliam (Mount Pelée), and other high points from 8 to 20 miles east to the mouth of the Moose River.” The contact was not studied by the writer, and since difficulties were encountered by Walcott in drawing the boundary, we lack definite knowledge of the relations between the two series. ToOPoGRAPHIC FEATURES, WITH DETAILS AS TO SYNONYMY AND - STRATIGRAPHY CHETANG CLIFF (§ 10) Chetang Cliff is a new name applied by Walcott to a cliff southwest of Coleman Brook. The cliffs expose the Chetang limestones, but the con- tact with the underlying formations and the portion up to and including the Albertella fauna is much better exposed in the summit of Mumm Peak. THE EXTINGUISHER (§ 11) The Extinguisher,'* a small cone of black rock in the Robson glacial cirque, is referred to by Walcott as Billings Butte. Its especial interest lies in the fact that the fauna found in its rocks is, so far as we know, the youngest in the Mount Robson region, and outcrops in place in the beds immediately overlying those forming the summit of Mount Rear- guard (§§ 23c and 23f). It is not improbable that the fauna occurs near the summit of Mount Robson itself ($§ 23d-e). The Extinguisher - beds are much higher stratigraphically than those in the top of Lynx Mountain (§ 24d). MOUNT HITKA (§ 12) Mount Hitka is a name given by Walcott to the high ridge northeast of Mumm Peak and separating that peak from the valley of the Smoky River. From it is derived the name of a formation which he describes as occurring between the Tatay beneath and the “Mumm” above. As we 17 Coleman: The Canadian Rockies, new and old trails. ~ TOPOGRAPHIC FEATURES dss © have shown (§ 27)), there is duplication, and the beds called “Hitka” are those called Titkana in the mountain of the latter name. HOTA CLIFF (§ 13) Hota cliff, on the northeast side of Coleman Brook, is in a position to expose the Hota formation if there is no faulting to the southwest; but the exposures are very poor, the contacts with the overlying Chetang and the underlying Mahto are covered, and no fossils are recorded by Walcott. The description of the rocks bears no resemblance to that of the rocks occupying the corresponding stratigraphic position in Mumm Peak, .where the contacts and every foot of the formation are exposed (§ 309). LYNX MOUNTAIN (§ 14) Lynx Mountain: Wheeler, 1912, Canadian Alpine Journal, volume 4, map. Phillips Mountain: Walcott, 1913, Smithsonian Miscellaneous Collections, vol- ume 57, number 12, page 333, plate 57, figure 2, and plate 58, figure 1. (Credited by Walcott with a height of 9,542 feet, which is the height of Lynx Center Station of Wheeler.) Lynx Mountain (10,471 feet high) is the topographic feature to which Walcott has applied the name “Phillips” ($17), his photographs leaving no doubt as to the mountain meant. The mountain to which he applies the name Lynx is a still unnamed peak, of unknown height, southwest of Lynx Mountain. 3 Walcott’s description of the Lynx formation states that it forms almost the entire mountain to which he gave that name, but we are not certain of its presence in this snow-and-ice-covered peak. The Lynx formation does outcrop, however, in Walcott’s “Phillips Mountain”; and, since this is the real Mount Lynx, the name Lynx is entirely appropriate to the formation (§ 24). _ MAHTO MOUNTAIN (§ 15) Mahto Mountain was proposed by Walcott for the ridge separating Smoky River from Calumet Creek. The Mahto formation is better ex- posed, because of its observable relations to fossiliferous overlying and underlying formations in Mumm Peak (§ 16), but the name Mahto has been retained. MUMM PEAK (§ 16) Mumm Peak’* (9,740 feet) is the high point directly north of Mount Robson, on the north side of Robson Pass, and is described by Walcott as exposing the Hota, the Mumm (typically), and the Titkana, and by 18 Wheeler: Canadian Alpine Journ., vol. 4, 1912, p. 36. 734 L. D. BURLING——-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON necessity the intervening Chetang, Tatei, and Hitka formations. As a ~-matter of fact, the so-called “Hota,” just above the Mural Glacier,’ is the “Tah” (§§ 30d, 32b-e), and the top of the mountain does not expose the Titkana, but the Chetung (§§ 26b and 29b). The succession in Mumm Peak is not (reading from the base upward) “Hota,” Chetang, Tatei1, Hitka, Mumm, and Titkana, but “Tah,” Mahto, “Hota,” and Chetang (§§ 30g and 32c). “PHILLIPS MOUNTAIN” (§ 17) Phillips Mountain was proposed by Walcott (page 333) for a station (Lynx Center, 9,542 feet) which Wheeler”? was forced, by the lateness of the day, to occupy on the crest of the north aréte of Lynx Mountain, but in his illustrations (plates 57 and 58) Walcott applies the term Phillips to Lynx Mountain, assigning to the latter an elevation of only 9,542 feet and crediting the unnamed peak between Mounts Resplendent and Lynx with the name Lynx and the height (10,471 feet) determined by Wheeler for the real Mount Lynx. Lynx Center Station lies on the sky line of Walcott’s figure 2 of plate 57, half way between the two glaciers to the left of the summit (see the plate opposite page 22) of Wheeler’s report, which represents the view from this point). MOUNT REARGUARD (§ 18) Mount Rearguard (9,000 feet) was named by Coleman?’ and con- firmed by Wheeler.*? It is the mountain which Walcott suggested chang- ing to Lyatunga; but the new name has not appeared in the decisions of the Geographic Board of Canada. The mountain is described by Walcott as one of the two mountains best exposing the Middle Cambrian Titkana limestones; but examination of the section showed that even the oldest rocks exposed in the mountain lie much higher than the Middle Cam- brian Titkana. The mountain affords a wonderful and very fossiliferous * section of the Upper Cambrian from the Extinguisher Ordovician fauna, at the top, to low down in the Lynx formation, at the base. MOUNT ROBSON (§ 19) Mount Robson (15,068 feet) is already so well known that we shall not discuss its discovery or nomenclature. A brief discussion of the wonderful section exposed will be found under the heading “Robson 19 Smithsonian Misc. Coll., vol. 57, no. 12, 1913, pl. 59, fig. 1. 70 Canadian Alpine Journ., vol. 4, 1912, p. 19. 21 The Canadian Rockies, new and old trails. = Canadian Alpine Journ., vol. 4, 1912, p. 36. TOPOGRAPHIC FEATURES 130 limestones” (§ 23). With the rocks as abundantly fossiliferous as they are, it is to be hoped that some mountain-climber who reaches the top will slp a small chunk of the rock in his pocket before beginning the clescent. TAH MOUNTAIN (§ 20) Tah Mountain was proposed by Walcott for the peak occupied by Wheeler as Moose Pass Station (see his map of 1912). Walcott uses the name for the “Tah” formation, but Tah Mountain has not received the approval of the Geographic Board, and the published description of the formation has been so confused (§§ 30a-d, 32b-e) that we have given to it the name of Mural limestone formation (§ 329). TATEI CLIFFS (§ 21) Tatei cliffs (revised by the Geographic Board of Canada from “Tatay” of Walcott) is a name applied to the uppermost of three cliffs southwest of Coleman Brook and above and to the southwest of Chetang cliff for the purpose of obtaining a formation name which has been retained. TITKANA PEAK (§ 22) Titkana peak (9,320 feet) was first called Ptarmigan Peak by Cole- man, who thus duplicated the name of a mountain north of Lake Louise, on the Canadian Pacific Railway. The name Ptarmigan was also given to the pass between the mountain of that name and Lynx Mountain. Wheeler”® calls attention to the duplication and suggests Snowbird Moun- tain and Pass, but on his map he applies the term Snowbird to the pass only. Walcott accepts Snowbird for the pass, but proposes a new name, Titkana, for the peak, and the latter has been accepted by the Geographic Board of Canada. ) The section exposed in the mountain corresponds with Walcott’s gen- eral description, so far as the Titkana hmestones are concerned, the only changes made in the present paper being in the total thickness and in the discovery of many abundantly fossiliferous horizons. The underlying limestones in the cliffs above Lake Adolphus, which Walcott refers to the “Mumm,” are, however, to be referred to the Tatei instead ($§ 26 and 28). 8 Canadian Alpine Journ., vol. 4, 1912, p. 37. 736. L. D. BURLING—-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON GEOLOGIC FORMATIONS, WITH DETAILS AS TO SYNONYMY AND STRATIGRAPHY “ROBSON LIMESTONES” (§ 238) (§ 23a.) The “Robson hmestones” are estimated by Walcott to extend from the summit of Mount Robson some 3,000 feet down, and are de- scribed as “light gray or dove-colored and bluish gray, thin-bedded lme- stones,” the upper half, or 1,500 feet, being described as practically in- accessible in the summit of the peak and appearing to be more massive bedded and arenaceous than the beds below. ($ 23b.) Two fossil localities are described, one in drift blocks brought down by the “Chupo Glacier” (61w), which is stated to “indicate a horizon very close to, if not within, the base of the Ordovician,” and the other (61q) in the Extinguisher (“Billings Butte”). The species listed by Walcott from the drift on the “Chupo Glacier” certainly form an assemblage which the average paleontologist would have little hesitancy in placing in the Cambrian, with the possibilities as much in favor of the Middle as the Upper. However, one opinion re- garding the actual fossils is worth more than a number of opinions based on a list of species. We can only call attention to the fact that it is a drift locality, to the fact that there are thousands of feet of Middle and Upper Cambrian beds outcropping above the place in which it was found, and to the fact that it appears to be represented in the collections at our disposal from the Mount Robson region in the limestones of the Titkana formation. | ($ 23¢.) The species listed by Walcott from locality 61q in the Ex- tinguisher are described as.an assemblage “of Upper Cambrian and Ordovician types,” which indicate the base of the Ordovician. For this reason the isolated?* Extinguisher beds are referred by Walcott to the lower portion of the “Ordovician Robson hmestones.” The discovery of the Extinguisher beds and fauna in the uppermost portion of the Mount Rearguard section has, however, afforded us data as to the actual rela- tions existing between the Extinguisher beds and the Lynx lmestones, and consequently between the Ordovician and the Upper Cambrian. - (§ 23d.) The writer secured known fossil horizons in the limestones of Mount Robson 1,600 feet above the level of Berg Lake, or at an eleva- tion above sealevel of about 7,100 feet. Since Mount Robson has an alti- 24 Walcott (Ann. Rept. Smithsonian Inst. for 1915, p. 252, and Nat. Geog. Mag., vol. 24, 1913, p. 633, legend) speaks of a ‘“‘satisfactory tie’’ made on the basis of dips, but a visit to Mount Rearguard, which must have shared in such a visual correlation, shows it not to be “Middle Cambrian,’ but Upper Cambrian in age, and leaves the position of the Extinguisher fauna in Mount Robson open (S§§ 23f, 24d). GEOLOGIC FORMATIONS 737 tude of 13,068 feet, there is room for some 6,000 feet of beds (the strata are very nearly horizontal) between the fossil horizon secured and the top of the mountain. Now, the fossil horizon secured is equivalent to the base of bed number 11 in the Titkana limestones, 1,100 feet below the top of the formation, which, with the thickness of the Lynx hme- stones (4,950 feet); yields a total thickness of 6,050 feet between the 7,100-foot (elevation) fossil horizon and the Extinguisher fauna. The stratigraphic position of this fauna (Extinguisher) and the top of the mountain should, therefore, coincide, and from this point of view there seems to be no room in the top of Mount Robson for strata younger than those carrying the Extinguisher fauna. (§ 23e.) The unbroken section of 9,809 feet, stretching from the sum- mit of Mount Robson (13,068 feet) down to the level of Lake Kinney (3,259 feet), which les close to the top of the basal clastics, also yields a figure which compares very favorably with the 9,850 feet of measured beds between the basal clastics and the Extinguisher fauna. Of course, 50 feet in 10,000 is more accurate than the rocks are, to say nothing of the measuring, and we do not know the extent of the break in the Lynx Mountain section or just how far below the surface of Lake Kinney the basal clastics begin; but while the closeness of the correspondence is purely adventitious, the approximation confirms our interpretation of the stratigraphy. (§ 23f.) Above the Lynx limestones there is a thin-bedded series of shales and interformational conglomerates (375 feet exposed) carrying an abundance of Ordovician fossils (the Extinguisher fauna) ; and while these have nothing in common with the published descriptions of the “Robson limestones,” except possible occurrence on the top of Mount Robson, they might, perhaps, receive the name Robson shales at the hands of a future student who shall find them there. They do occur in the Extinguisher and in the summit of Mount Rearguard. LYNX FORMATION (§ 24) (§ 24a.) The Lynx hmestones are described by Walcott as unfossilif- erous and as beginning on the south slope of Titkana Peak, near Snow- bird Pass, and extending over “Phillips Mountain” (Lynx Mountain) into the base of “Billings Butte” (the Extinguisher), to the horizon of the Extinguisher fauna, with a thickness of 2,100 feet. (§ 240.) As determined by sections measured back of the summit of Titkana Peak, in Lynx Mountain (Walcott’s “Phillips”), and in Mount Rearguard (Walcott’s “Iyatunga”) (§§ 17 and 18), the Lynx formation has a thickness of 4,950 feet to the horizon of the Extinguisher fauna, is 738 LL.D. BURLING——-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON abundantly fossiliferous, and is one of the most eat es of the formations in the region. (§ 24c.) The Lynx formation extends from the base of the Upper Cambrian to the base of the Ordovician. It is marked at the base by a series of shales which exhibit shallow-water phenomena ($7), and, hke the Upper Cambrian in so much of the Cordillera, is frequently charac- terized by interformational conglomerates. The limestones forming the upper part of the Lynx formation are cliff-forming, and the line between the Upper Cambrian and the Ordovician is drawn between them and an overlying series of shales and thin interbedded interformational con- glomerates which carries the Extinguisher fauna and which is referred to the Ordovician. The line occurs about halfway up in the section ex- posed in the Extinguisher and at the top of Mount Rearguard. ($ 24d.) Walcott describes the Lynx formation as lying below the Extinguisher fauna-—a definition which is accepted—one of the reasons for the discrepancy between the figures of 2,100 and 5,000 feet respec- tively for the thickness of the formation being his assumption that Mount Rearguard exposed the Middle Cambrian, and that the Extinguisher beds directly overlay those of Mount Lynx. Mount Rearguard exposes the upper portion of the Lynx and is itself directly overlain by the Ex- tinguisher beds and fauna. Mount Lynx exposes only the lower portion of the Lynx formation. Titkana limestones: Walcott, Smithsonian Miscellaneous Collections, volume 57, number 12, 1913, pages 330, 334, 337, and 341. Hitka formation, as far as both position in section and exposure in Hitka Mountain: Walcott, idem, pages 334, 338, and 341. Titkana: Burling, Museum Bulletin number 2, Geological Survey of Canada, 1914, page 109. Hitka: Burling, idem, page 109. Titkana: Walcott, Problems of American geology. New Haven, 1915, page 179. Hitka: Walcott, idem, page 179. TITKANA LIMESTONES (§ 25) (§ 25a.) According to Walcott, the Titkana limestones have an esti- mated thickness of 2,200 feet and are best seen in the west slopes of Titkana Peak and in Mount Rearguard (“Iyatunga”). As has already been shown (§$18 and 24d), this formation is not present at all in Mount Rearguard, but the section in Titkana Peak exposes both the top and bottom of the formation. : Two fossil horizons were secured by Walcott—one, locality 61v, in a cliff just above the Robson Glacier, and the other (611 and 61m) 1% miles west-northwest of the summit of Titkana Peak. The first of these GEOLOGIC FORMATIONS 739 localities (61v) contains a fauna comparable to the fauna of the Stephen formation in the Canadian Pacific Railway section, and is represented in our collections from the mountain (Titkana) itself by a locality 600 feet above the base of the formation. The second of the two localities (61/ and 61m) is represented in our collections from both Titkana Peak and “Mount Hitka” by a locality at the base of the formation 600 feet below the horizon of the Stephen fauna. (§ 250.) As has been described under the “Hitka” (§§ 12 and 27d), there appears to be duplication involving that formation and the Titkana. Our reason for choosing the term Titkana and abandoning the Hitka is that while the former is stated to be unfossiliferous, Walcott found two fossil horizons in the Titkana, and the latter formation is much better exposed in the peak of the same name than is the Hitka in Mount Hitka. A comparison of the abundant fossils found in many horizons of the “Witka” and the Titkana confirms their identity. “MUMM LIMESTONES” (§ 26) (§ 26a.) According to Walcott, the “Mumm limestones” are Middle Cambrian, massive-bedded, gray, arenaceous limestones weathering to gray and buff tints, with an estimated thickness of 600 feet, and occur (1) in the northwest base of Titkana Peak (— Tatei limestones), (2) on the westward slope of the ridge east-northeast of the lower end of Lake Adolphus (= Tatei hmestones), and (3) in the upper part of Mumm Peak (== Hota limestone). No fossils were found. ($ 26b.) As has been stated already (§ 16), inspection of the rocks forming the top of the mountain proved them to belong to the Chetang, a formation which is described by Walcott as lying 2,500 feet below the “Mumm,” and is, according to his section, separated from that forma- tion by two other formations. The Mumm limestones are, therefore, non-existent, so far as Mumm Peak is concerned—in fact, the limestone to which the name was there applied is the “Hota” (§§ 306, 30g, and 32¢). We have shown (§§ 28 and 27b) that the limestones in localities 1 and 2 above are to be referred to the Tatei, and that there is a duplica- tion in Walcott’s section which involved the confusion of the Mumm with the Tate1 and the Hitka with the Titkana. The absence of any fossils in Walcott’s collections from the Mumm, Hitka, and Tatay formations, 3,100 feet, made the identification of his section in the field a slow process, the problem being further complicated by the facts (a) that neither the Mumm limestone nor any limestone of the age assigned to the Mumm occurs in the mountain in which it is stated to be typically developed (§ 382c), and (b) that the “Hitka,” in the mountain of that 740 1. D. BURLING—-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON name, is not overlain by the massive limestones of the Mumm, but by a series of red shales indistinguishable from the basal Lynx (§27b). For these reasons we have not used the name Mumm in this paper. “HITKA FORMATION” (§ 27) (§$ 27a.) The “Hitka formation” is described by Walcott as occurring (a) between the Tatay cliffs and the Mumm limestones, on the westward slope of the ridge east-northeast of the lower end of Lake Adolphus, and (6) in Hitka Mountain. (§ 276.) Five formations were found by the writer in Mount Hitka— a middle one underlain by two limestones referable to the Tatei and the Chetang respectively (all fossiliferous) and overlain by red and yellow shales referable to the Lynx. If the “Hitka” is the upper red and yellow shales, it is underlain by.the Titkana instead of the Tatei; if it is the middle formation, it is clearly identical with the Titkana. The fossils amply corroborate this. TATEI LIMESTONES (§ 28) Mumm limestones (locality near lower end of Lake Adolphus): Walcott, Smithsonian Miscellaneous Collections, volume 57, number 12, 1913, page 330. Not Mumm limestones, given as typically exposed in upper part of Mumm Peak: Walcott. idem, pages 334. 337 (= Adolphus, §§ 30a. 306, 30g, and 32¢). Mumm limestones, so far as position below TitKana limestones in general sec- tion is concerned: Walcott, idem, pages 334, 337, 341. Mumm limestones, exposure at northwest base of Titkana Peak: Walcott. idem, page 337. Not Mumm limestones, so far as description is concerned: Walcott. idem, pages 334, 357, 341 (drawn from an outcrop of the “Hota’’). Tatay limestones, so far as position above the Chetang and occurrence in Tatei cliffs is concerned: Walcott, idem, pages 334, 338, and 341. Mumm formation: Burling, Museum Bulletin number 2, Geological Survey of Canada, 1914, page 109. Tatay formation: Burling, idem, page 109. Mumm formation: Walcott, Problems of American geology, 1915, page 179. Tatay formation: Walcott, idem, page 179. ($ 28a.) The Tatei limestones are described by Walcott as being massive-bedded, gray, siliceous, and arenaceous, with an estimated thick- ness of 800 feet and without fossils. (§ 28b.) As has been described in the discussion of the “Hitka lime- stones” (§ 27) and the “Mumm lmestones” (§ 26), this formation over- hes the Chetang and underlies the Titkana instead of the “Hitka,” both anes GEOLOGIC FORMATIONS (41 the “Hitka” and the “Mumm” representing duplications in the section and being none other than the Titkana and the Tatei respectively. CHETANG LIMESTONES (§ 29) (§ 29a.) According to Walcott, these are Middle Cambrian in age, have an estimated thickness of 900 feet, and outcrop in Chetang cliff. Fossils were found by Walcott in the Chetang limestones and the forma- tion affords a known point from which to begin our interpretation of Walcott’s section of the over- and under-lying rocks. ($ 296.) Though the formation can be seen and is fossiliferous at the type locality, exposures are there poor, especially with regard to the upper and lower boundaries, and the latter is important, since it is de- scribed by Walcott as involving the contact between the Lower and the Middle Cambrian. This conception of the stratigraphy differs from the one presented in this paper ($§ 8, 30¢). The lower part of the Chetang limestones is very well exposed and is very fossilferous at the top of Mumm Peak (§§ 16, 26), 30g, 32c), but erosion has there removed the overlying rocks. Several Albertella horizons were also found in a section exposed in the gorge below Mural Glacier. ADOLPHUS (“HOTA”) LIMESTONE (§ 30) Hota formation, so far as position in the section is concerned: Walcott, Smithsonian Miscellaneous Collections, volume 57, number 12, 1913, pages 335, 338, and 341. (The description of lithology and the lists of included fossils are derived from an exposure of the “Tah” (Mural limestone) in Mumm Peak, just above the Mural Glacier, which was mistaken for the Hota) (§§ 30d, 320). : Mumm limestones, so far as both description and position in Mumm Peak are concerned: Walcott, idem, pages 334, 387 (§§ 30g, 32c). Not the Mumm limestones listed as occurring near lower end of Lake Adol- phus: Walcott, idem, page 330 (= Tatei, §§ 22 and 26b). Not the Mumm limestones listed as occurring in northwest base of Titkana Peak: Walcott, idem, page 337 (= Tatei, §§ 22 and 260). Hota formation, so far as position in the section is concerned: Burling, Mu- seum Bulletin number 2, Geological Survey of Canada, 1914, page 109. Hota formation, so far as position in the section is concerned: Walcott, Prob- lems of American geology, 1915, page 179. (§ 30a.) The “Hota formation” is described by Walcott as composed of a series of “gray arenaceous limestones and siliceous shales alternating with massive quartzitic sandstones,” 800 feet thick and lying beneath the hmestones of the Chetang formation on the southwest side of Coleman Brook. By definition it is the formation separating the Mahto from the Chetang. 742 L. D. BURLING—-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON (§$ 30b.) Now, the formation occupying this position in the contin- uous and fossiliferous section of the “Tah,” Mahto, “Hota,” and Chetang formations ($$ 16 and 32c) exposed in Mumm Peak is a massive 300- foot cliff-forming, gray arenaceous limestone, with transitional clastics at the base; and it is this bed which Walcott took to be a younger lime- stone, 3,400 feet higher in the section than the “Hota,” and to which he gave the name “Mumm limestone” (§§ 265 and 32c). ($ 30c.) Walcott (page 339) refers to the “Hota” as the “New Lower Cambrian subfauna” described by him in the preceding number of the Miscellaneous Collections (volume 57, number 11). This fauna was mostly collected from drift blocks on the surface of Mural Glacier, but Walcott (legend to plate 59) locates the horizon in the cliffs just above the glacier. ($ 30d.) A section of the beds in this locality, beginning at the gla- cier, passes up through the “Tah” into the Mahto sandstones, and shows (a) that the beds in the position indicated by Walcott he approximately 2,500 feet below the “Hota,” and (0) that the general description given for the lithology of the “Hota” was derived from an exposure of the “Tah” ; for, unless Walcott’s “Hota” is incorrectly defined as underlying the Chetang and really hes 2,500 feet below that formation and beneath a massive series of quartzites, the beds containing the “New Lower Cam- brian subfauna” can in no way be referred to the “Hota” and must be referred to the “Tah” (see § 32). (§ 30e.) Walcott places the “Hota” formation in the Lower Cambrian, but the Olenellus, on which this correlation is based, occurs in the “Tah” at a place where the latter had been identified as “Hota.” Naturally, therefore, the line between the Lower and Middle Cambrian was drawn at the top of the “Hota”; but we have found typical Middle Cambrian fossils in the base of the “Hota” without Olenellus, and have drawn the Lower-Middle Cambrian boundary below ($§ 8, 30f, 31c, 32d, 32e). (§ 307.) It will be noticed that our generalized sections (§ 2) gives the “Hota” (Adolphus) a thickness 400 feet less than Walcott, and it should be stated that neither the addition of 400 feet from the overlying Chetang, nor the addition of any number of feet up to one thousand, apparently, from the underlying Mahto would add Lower Cambrian fossils to the “Hota,” though it would explain the reference to quartzites in Walcott’s description of: the “Hota.” (§ 30g.) Lest any one should think that the differences between Wal- cott’s interpretation and my own are due to failure correctly to identify his formations, it may be stated that his “Hota” is the formation under- lying the Chetang, however it is described lithologically, and the Chetang 7 / GEOLOGIC FORMATIONS 143 is one of the three formations in which Walcott found fossils. Its iden- tification at the type locality as well as in Mumm Peak is based on in- disputable fossil evidence, and the formation directly underlying it in Mumm Peak must, therefore, be the “Hota.” That this is so is further proved by the presence, below the Mumm Peak “Hota,” of a series of quartzitic sandstones comparable with the Mahto; and this section (Che- tang, “Hota,” and Mahto), reading from the top down, overlies, in one unbroken, perfectly exposed section (§$ 16 and 32c), the beds in which Walcott secured the “New Lower Cambrian subfauna” and which he thought to be the “Hota” of Hota cliff. For the sake of clearness, I have used the term “Hota” in speaking of this limestone in the preceding pages, but we have in this paper discarded the term “Hota” and adopted the name Adolphus, for the following reasons : te (a) Without fossils or observable upper and lower contacts, we can not be at all sure that the “Hota” even outcrops in the ridge named, but it does outcrop in the cliffs of Mumm Peak above Lake Adolphus in ob- servable relations to the overlying Chetang and the underlying Mahto ($$ 16 and 32c). 7 (b) The published descriptions of the “Hota” are based on exposures of the “Tah” (§ 30d). . (c) The real “Hota” (the limestone immediately underlying the in- disputable Chetang, which forms the summit of Mumm Peak) is de- seribed, located, and given the name Mumm (§§ 26 and 32c). (d) The fossils credited to the “Hota,” and these include a very i1m- portant assemblage of Lower Cambrian fossils, did not come from the “Hota,” but from the “Tah” (§§ 30c, 30d, 32c-e). (e) The “Hota” is described as Lower Cambrian, but it is so referred on the basis of fossils occurring a thousand or more feet lower in the section (§ 8a) and of a “New Lower Cambrian subfauna” which occurs 2,000 feet below (§ 30d). The “Hota” (Adolphus) is Middle Cambrian in age. MAHTO SANDSTONES (§ 31) ($ 31a.) The Mahto sandstones are described by Walcott as occurring between the more or less calcareous “Tah” (== Mural) hmestone forma- tion beneath and the similar, though more limy, “Hota” (== Adolphus) above. It was credited at first with the “new Lower Cambrian subfauna” which he later took out of the Mahto and assigned to the overlying “Flota” (§§ 30c, d, e, 82d, e). ($ 316.) The Mahto is described by Walcott as unfossiliferous and the boundaries we have drawn ($§ 30e, f, g, 32e) leave it without fossils as 744. L. D. BURLING——-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON well. The very base of the overlying “Hota” contains typical Middle Cambrian fossils, and the underlying “Tah” is abundantly fossiliferous, all of the horizons discovered in the latter being Lower Cambrian. ($ 31c.) The Mahto sandstones therefore represent an apparently unfossiliferous quartzitic series between the Middle Cambrian and the first Olenellus,”> and the line between the Lower and the Middle Cam- brian is drawn at the top of the Mahto formation (§§ 8, 30e, 30f). (§ 31d.) Our estimated thickness of 1,200 feet for the Mahto in Mumm Peak differs from Walcott’s estimate of 1,800 feet for its thick- ness in Mount Mahto, five miles away. The relation of the arenaceous beds above to the calcareous beds below, which is the basis on which the line is drawn in Mumm Peak, may vary in the distance separating the latter peak from Mount Mahto. 3 MURAL (“TAH”) LIMESTONE FORMATION (§ 32) Mahto formation, as the name for the beds carrying the “new Lower Cam- brian subfauna”’: Walcott, Smithsonian Miscellaneous Collections, volume 57, number 11, 1913, pages 311-316. (According to Walcott, § 32d, this use of the term Mahto was by error.) Hota formation, as the name for the beds carrying this fauna: Walcott, idem, number 12, 1913, page 339. (An error in identification, § 32c.) Tah formation, as the unfossiliferous formation between the Mahto and the McNaughton: Walcott, idem, pages 335 and 339. Tah formation: Burling, Museum Bulletin number 2, Geological Survey of Canada, 1914, page 109. (On page 108 the reference of the “new Lower Cambrian subfauna” to the Hota is questioned.) Tah formation: Walcott, Problems of American geology, 1915, page 179. Mahto formation: Walcott, Annual Report of the Smithsonian Institution for 1915, plate 17, 1916, page 254. (A reversion by inadvertence to the no- menclature of the first reference, § 32d.) Mahto formation, as the formation carrying one of the new Lower Cambrian subfauna forms (Padeumias): Burling, Bulletin of the Geological So- ciety of America, volume 27, 1916, pages 158-159. (The error of placing this fauna in the overlying “Hota” had been recognized, but the line be- tween the Mahto and the underlying “Tah” was at this time drawn so as |. to include the fauna in the Mahto—S8§ 81), 32d, 32e.) Mahto formation, as the formation carrying the Pedeumias above mentioned : Burling, Ottawa Naturalist, volume 30, 1916, page 55. (See note to pre- ceding reference. ) (§ 32a.) The “Tah” formation is described by Walcott as occurring just above Moose Pass, at the base of “Tah Mountain,” with a thickness 2 It is, of course, possible that the Olenellus fragments credited to the Mahto on page | 335 of Walcott’s paper did come from the Mahto, and that the formation is not unfos- siliferous, as stated on page 369, and the rocks are so frequently fossiliferous that many may be found in the Mahto by the next observer. GEOLOGIC FORMATIONS 745 of 800 feet, unfossiliferous, and resting on a few layers of McNaughton sandstones before the whole section is cut off by a fault which brings down the Upper Cambrian. : ($ 32b.) This formation is the one which Walcott found occurring just above the “new Lower Cambrian subfauna” in the moraine of the Mural Glacier and identified as “Hota” ($§ 30 and 31). This threw out the whole Mumm Peak section and resulted in the identification of the thin-bedded quartzites of the Mahto as the Chetang and the description of the real “Hota” (now called Adolphus), which stands out clear and distinct as a cliff above, for a new and much higher limestone, to which the name Mumm was given. (§ 32c.) It should be recorded that when I reached the summit of Mount Hitka, approaching it from the valley of Smoky River, I did not know that the faulting between Mount Hitka and Mumm Peak was as large as it is, and I had not the slightest doubt that I was viewing the section described by Walcott—Mumm, Hitka, Tatei, Chetang, and Hota, listing them from the top down. I was the most surprised of individuals when I started up the north face of Mumm Peak, and, after passing through Walcott’s “Hota,” with its profusion of Olenellus (the “new Lower Cambrian subfauna”’), reached a quartzitic series more than a thousand feet in thickness, instead of the Middle Cambrian Chetang limestones. It was not until I reached the summit of Mumm Peak from the south side that I could realize (a) that the limestone to which Wal- cott had apphed the name “Mumm” was really the “Hota,” and (b) that the Mural Glacier fossils (the “new Lower Cambrian subfauna”’) came not from the “Hota,” but from a horizon approximately 1,750 feet below. (§ 32d.) I first drew the line between the “Tah” and the Mahto below bed number 8 of the north face section, and in my description of Pedeumuas robsonensis’® | referred this form to the Mahto. This coin- cided with Walcott’s reference of the “new Lower Cambrian subfauna,”’ of which Pedeumias robsonensis is a member, to the Mahto.?7 I thus ignored the fact that the same fauna had been referred three days later?® to the “Hota,” and accepted its re-reference to the Mahto three years -later.?° This reference of Pedeumias robsonensis, and therefore of the new subfauna, to the Mahto was, however, questioned by Mr. Resser, of the United States National Museum, in a personal communication : 76 Ottawa Nat., vol. 30, 1916, p. 55. *1 Smithsonian Misc. Coll., vol. 57, no. 11, 1913 (July 21), pp. 309-326. *8 Idem, no. 12, 1913 (July 24). pp. 338, 339. * Ann. Rept. Smithsonian Inst. for 1915, pl. 17, p. 254, 1916. 3) XLIX—BULL.. Grou. Soc. Am., Vou. 34. 192 746 LL. D. BURLING—-CAMBRO-ORDOVICIAN NEAR MOUNT ROBSON “In the description of the species Pedeumias robsonensis you give the horizon as Mahto. Walcott in his description of this fauna gives it thus also, but in his next paper (July 24) he gives the fauna as occurring in ‘the Hota. I called his attention to this difference and he says the correct formation is the Hota.” (§ 32e.) As we have shown (§8§ 30c, d, g, and 32c), the “new Lower Cambrian subfauna”’ of Walcott occurs not in the “Hota,” but in the Mahto or the “Tah.” In the absence of any recognizable break, the line between these two formations has now been drawn (§ 80) so as to include in the overlying Mahto only the dominantly arenaceous series and so as to transfer to the underlying “Tah” the essentially calcareous series. Such a separation places the “new Lower Cambrian subfauna” 550 feet below the top of the “Tah” (Mural limestone) formation. The differences between the interpretations of Mr. Walcott and myself are in no way dependent on the drawing of the line between the “Tah” and the Mahto. He said, and repeats through Mr. Resser, that the “new Lower Cambrian subfauna” came from the “Hota,” a formation over- lying the Mahto. We have visited the type locality and have found the fauna under discussion in the “Tah,” a formation underlying the Mahto. (§ 327.) The Mural limestone formation is one of exceptional interest ; and while all of the fossils secured by Walcott, as well as the specimens described by the writer, were secured from drift blocks in the lateral moraine of the Mural Glacier, an abundant fauna has now been secured from the formation itself. In addition to being very fossiliferous in its locality above the Mural Glacier on Mumm Peak, the Mural limestone formation is there shown in observable relations with its over- and under- lying formations. The underlying sandstones (not certainly to be corre- lated with the McNaughton sandstones of Walcott) are here over 400 feet thick. (§ 32g.) Our main reasons for making the change from “Tah” to Mural are the failure of the Geographic Board to accept the name, the remoteness of the mountain, the absence there of observable relations to the other formations and of fossils, and the confusion of the “Tah” and the “Hota,” stratigraphically, lithologically, and paleontologically. MC NAUGHTON SANDSTONES (§ 33) (§ 33a.) The McNaughton sandstones are described by Walcott from the McNaughton Mountains, some 20 miles distant from the locality in which the other formations were identified. They are there given an estimated thickness of 500 feet and are described as unfossiliferous. The a! GEOLOGIC FORMATIONS fA] drawing of a line between them and the Miette sandstones is described as a matter of some difficulty (§ 9). ($ 330.) The quartzitic limestones which underlie the Mural lime- stone formation in the Mount Robson region may or may not be directly underlain by the pre-Cambrian, and may or may not be correlateable with the McNaughton sandstones. Even though they form, so far as known, the exposed base of the Cambrian sequence in the Mount Robson region, we prefer to leave their naming to the future student who shall determine their relations to the pre-Cambrian. MIETTEH SANDSTONES (§ 34) The Miette sandstones are described by Walcott as having an esti- mated thickness of 2,000 feet, and as being best exposed along both sides of Yellowhead Pass from Grant Brook on the west to Fitzhugh on the east, and to be overlain by the McNaughton sandstones, the line of demarcation being very uncertain. The writer did not find the contact between the Cambrian and the pre-Cambrian in the Mount Robson region and is unable to add to the description given (§ 9). ae ) INDEX TO VOLUME 34 Page AEROLITE from Rose City, Michigan ; OM ETOWIG Vitra fea) Sts eae sve Se 97 Arrica, Diamond mines of South...... 150 —, Geological map of the Bushveld com- POSS MUTANS WEVA. Sire siete wae) bier ovis ee oes 95 —, Jurassic dinosaurs of..4.......... 405 SS VISE OF SOUEM: 2. 2 ee wees es cals 97 —Awvermiam fangs Of. cu... 6. ee 403 —, Schoepite from the Congo......... 150 AYRiICAN Protectorate, Vanadium de- posits. from southwest........... 150 AGASOMA, Phylogeny of the genus..... 118 A HIGH temperature vein in Madison County, Missouri; W. A. Tarr.... 99 ALAMO mining district, Mexico........ 119 ALASKA, Boreal marine fauna from.... 118 A LAYMAN’S view of the theory of isos- TESS (OS a Gael Bes ol aaa eae ee ieee 57 ALBAN Hills, Occurrence of leucite in (RG 2 ALS IR SEOe er RaOES IGS ae RIE carne ten naa 150 ALBERTA, Cretaceous dinosaurs of..... A0T —, Effect of Pleistocene glaciation in.. 82 —, Pleistocene glaciation in........... 419 ALDRICH, H. R.; Magnetic surveying on the copper-bearing rocks of Wis- GOIDRIIO «3.6 55 Gl sae eee Cae ne 145 ALLEGHENY formation in-western Penn- Eval busea TMA Mme neneriewe we vr itecei cles wie sah s dney so Sans 68 AMERICA, Cenozoic mammals of....... 408 AMERICAN rhinoceroses and the evolu- tion of Deceratherium; FE. S. Trox- ABIL <3 a2). Sta Ale JB oe AN effect of climatic change on the su- perficial alteration of ore deposits ; JEL, Jel: OTS OD 6 Sesion 146 ANDREWS, E. C.; Contribution to the hypothesis of mountain-building 61, 381 —; Geographic distribution of ore de- POSHES IM SCAUS PRAIA. os Se ae sees 144 PAGNONUPANMUOLUMTOI le ils foes oes ose) ha knee 75 APPALACHIAN bauxite deposits; W. 'N GIISO IDs dy eg Saas cg eee OT; 525 — I stricture, Outlines of...0......... 309 APPALACHIANS in southern New Eng- lemrderOroSS-SeCtiOn (Of... 6.2.06 oss 253 ARIZONA, Verde River lake beds in.... 119 ARNOLD, RALPH, and is Cranks: Fauna of the Sooke formation.... 118 ASnAumeneres, > VW. EL: Hobbs... ..2.. 538, 243 A sourcE of pressure for ore forma- OME Oe TAO. skis cit Sec cs-c ee ce 146 ATLANTIC Coastal Plain, Tertiary and Pleistocene terrace plains of...... Sil —States native copper deposits com- pared with those of Michigan..... 145 ATTEMPT to study the actual capillary relationships of oil and water; (SPM I OOOO oe execs oun tbe whee oes 00 AUDITING Committee, Election of...... 11 ——of the Geological Society, Report UlMEGe Spee sy eyo ers Sissies kos eh ca Chae 55 — — — — Paleontological Society, Ap- DOMAUTMEIN Ge Obani ee Gs chaus eteudgets dhe Ss 124 AUROUSSEAU, M., and N. L. BOWEN; Fusion of sedimentary rocks in MR CIHIMMTOLGS 2 orsid «head & sie ee wteoe Ne 96, 4381 AusmeAniA, Ore deposits Im... ........ 144 AUTUNITE of the uranite group....... 150 BALL, SyDNEY H., Secretary; Proceed- ings of the Second Annual Meeting of the Society of Economic Geol- ogists, held at Ann Arbor, Michi- gan, December 28-30, 1922....... Page BANDED postglacial clay near New York Giittya Cer ALR GCI Sar esta were eee 92 BARRELL, JOSEPH, Memorial of........ 18 —; Work on problems in sedimentation 28 BASSLER, R. S.; Embayments and over- lapsyiny central: Nennessee.. 2. 25... 132 —, Secretary ; Proceedings of the Four- teenth Annual Meeting of the Pale- ontological Society, held at Ann Arbor, Michigan, December 28-30, [Oe IS Un Sea SUR ena D eka it Ee 121 —; The problem of fossil multilamellar LMVETTADRAUCS) Patines clea oe ee 133 BATEMAN, A. M.; Primary chalcocite, Bristol copper mine, Connecticut... 146 BAUXITE deposits in the Appalachians. aPA5) Bayutey, W. S.; Titaniferous iron ores of western North Carolina........ 146 BEAN, HE. F.; Road materials investiga- ELOne My WHASGomsine 2) ely eee 146 BENTONITE deposits in the Appalachians 525 Berkey, C. P.; Geological reconnas- SANCes ane MVLOMe ONAL ws sin cies ese ee 80 =, Secretary Proceedings - of sthe Thirty-fifth Annual Meeting of the Geological Society of America, held at Ann Arbor, Michigan, Thurs- day-Saturday, December 28-30, 1922 1 BoLiviaAN and Michigan copper deposits COMM ANG CER eid sau eta hed eens ae Boom Beach (Isle-au-haut, Maine): A Seaman OMe @larke a. oe 2 eee 65 BorEAL marine fauna from the Upper Oligocene or Lower Miocene of JNJ ISI S73) Bihra De COME ig reeoemen eale ora 118 BoUuDINAGE, an unusual structural phe- NOMEN OM sale, Aes OMIT Rs ei eer ae 649 Seles KONASeralGeas oak cette ee 59 Bowen, N. L., and M. AUROUSSEAU; Fusion of sedimentary rocks in CLT SIN OLE Shen eee ey hae lo a siepak setae 96, 431 Bowl, WILLIAM; Present status of the geodetic work in the United States and the value to geology......... 74 BRANSON, E. B., and J. S. WILLIAMS; Evolution of Stropheodonta (de- missa (Conrad) in the Snyder Creek shales of Missouri......... 134 Bretz, J. H.; Glacial drainage in the Colmmibiapelapeaie | acs ee nies 92, 573 BRISTOL copper mine, Connecticut, CHATCOCUCE MEEOMI a a 5.he aon ce kansas eee, wh oR 146 BrRiTtisH COLUMBIA Cambro-Ordovician SQ COMM ate rorer eras cs oheee ev emant a cusonane (Pit —-—, Cretaceous age and early Hocene uplift of a peneplain in....... 99,561 Bucuer, W. H.: Further experiments on the fracturing of hollow brittle spheres and their bearing on major CDS OTIS TION ee Ais fens: amepfe 6 acer! okays eos 81 BUILDING of the southern Rocky Moun- HINTS sea ica De LO Gia tara nap x eevee sctusl 6 aalkers 285 BuRLING, L. D.; Cambro-Ordovician sec- tion near Mount Robson, British COTETINN Oa re honaene s nai aaee Corey oie ees alialin 721 BUR LON = DIGVOSPOMNEC ca.) < es clei sie aierer ole A BUSHVELD complex, Geological map of. 95 — igneous complex, Metamorphism of CORMELEUAT HEISE Hones [ike\eaum = Hat A egiy cehciohG aie 96 BuTuterR, B. §8.; Suggested explanation of the high ferric iron content of limestone contact zones.......... 750 BULLETIN OF Page BuWALDA, J. P.; Miocene age of the oil fields at Elko, Nevada........ 118 CATAINORNTAS Mauilite nap Oat wees oles 58 —, aults of the coast ranges of...... 58 —, Geographic nomenclature of south- ey Gl aCe ENS RG ae eh nem ER ee eR ore 67 —, Pleistocene vertebrates from Cali- fornia asphalt deposit........... 119 —, Reconnaissance traverse from Mo- JAVie WiIlOjaMera> pet ckene cin eewnees oerees fe CALVIN Lake, Iowa, Origin and history (0h caren AUC Pace ana Sonn Rae Mice Nilay A Ab tp Ate 93 CAMBRO-ORLOVICIAN section near Mount Robson, British Columbia; L. IS URLS”, actcnc! ccer cctascaue cole eater aliemay eee 174i CANADA, Cretaceous dinosaurs of AI- DOTA SER ees oe canst ewencleka sige ee tore 407 —, Hllsworthite from Hybla, Ontario... 150 —, Pleistocene glaciation in Alberta... 41¢ CANADIAN and Ozarkian systems...... 134, —- Pleistocene concretions............. 60% CAPILLARY relationships of oil and WAIL GIs doay Gesteacecate Aeconee ee nian aac meester 106 —vrelations of oil and water; C. W. (GOO pare aia oer che caer ashore ey owen eee 145 CaRLILE shale and Timpas limestone, IMPS NO Rene cro eam es veh edema ane ake 9 Pave peel asee aes at ameneN aor eae 7 CARMAN, J. E.; Preliminary report con- cerning some new Ostracoderms FLO Ms ( OMG Sar al Aaah es ee eae loaner 133 CARNIVOROUS Saurischia in WHurope later than the Trias; F. von Huene 133 — —-— — since the ‘Triassic; F. von EWE MG? Ce Rveohe ap eee s Geer tee nes oon 449 CARNOTITE of the uranite group....... 150 CATAPELITE from Magnet Cove; W. F. LEVIS) CVS esas ets witie aon ose ice Pa BLOROa) GOREN 149 CEBU, Tertiary and Quaternary dias- BICONMIRES| UO nh NaceP nar eis MwA meEn BioLaiG ars 59 CENOZOIC mammals of America....... 408 CuHapwick, G. H.; Glacial lake prob- EIS yh ee ae hae acct atte el UALS eeeens 92, 499 —;Chemuneg stratigraphy in western ING We SViGT Kee oir seventy Sane ei eee are —;Successful method of teaching his- HOLLCAL IS COMG OViee erates ee neee eae 67 CHANEY, R. W.; Paleobotanical contri- butions to the stratigraphy of cen- EVA ORTON ec hs cee ee oe ee Oe 129 CHEMICAL Suggestions concerning the origin of Lake Superior copper OLESi tebe. CEN WielISAe ances ome ee 100, 144 CHEMUNG stratigraphy in western New Moree see vet s@ilhia@divalckere tvs mies, eee 68 CHINA, Geological sketch of the Tsin- TAS = SIVENTT aes so Tee coe ce eee eRe eas 119 —, Pliocene mammals of southern..... 128 CHALCOCITE from Bristol copper mine, Comme cricuiie sce eee os Oo 46 CINCINNATI province, Basal Richmond OL CGS ein pecan Roe Reet ey eee eee eens 3 CLaRK, B. L.; Boreal marine fauna from the Upper Oligocene or Lower Mioceniemoie Alaskkalin sss nieces ieee 118 —; Myadesma, a new genus of pelecy- B poda from the marine Oligocene of tHE West COASEEedee oe eee 118 —and RALPH ARNOLD; Fauna of the SOOKE ORM aio Mee ce crea eee ee 118 CLARK, Bruce; Marine Eocene horizons of western North America........ 134 CLARKE, J. M.; Boom Beach (Isle-au- haut): A Leen eRe Oe SMS Be 65 ; Pyorrhea in the Cohoes mastodon.. 127 —; Restoration of the Cohoes mastodon 127 plemple: Hill “mastodonern ) eee Soothe Burton Dictyosponge..... 2... 127 THE GEOLOGICAL SOCIETY OF AMERICA Page CLARKE, N. T.; Restoration of masto- GORD YE. ee TS sachet eres es 127 CLIMATES, Problem of mild geological. 81 Coast ranges and Sierra Nevados; Bai- Ley oe Willis. Svs kcreses Mae 53 or ac oaeenees 58 COHOES MAS COG OM iy .cs ice uckcos. oe eRe 127 COLORADO and Wyoming oil-bearing rocks), Correlations 2 Of seie see 145 — Front Range, Physical history of... 87 —, Merging of Carlile shale and Timpas limestone formation in........ 74, 495 — Plateau, Origin and structural fea- tures ofS Goes enlist ee meen as Plateau, Glacial drainage on ae 1 0: en See ee ERUR Pe Re To bn a ui Washington, Glacial drainage bs OM, ue do Sess ea aes Sessa Ce eee 2 —-—, Topography and geology of..... 75 CoMMITTER, Appointment of Paleonto- logical Society’s Auditing........ 124 —of Cordilleran Section on Nomina- BLOTS > 6.08055 esosiat rence bollane Tonos ol Cn Omen ERR eae 120 —on Teaching Geology, Report of.... 14 COMPOSITION of Thomsonite; HK. T T UWOPTLYe: sic: 5 Suc hates ccoee tos een 150 CONCENTRATION and circulation of the elements from the standpoint of economic geology; Presidential ad- dress' “by Wi. Jind s tenes 144 CONCRETIONS, Canadian Pleistocene... 64 CONGO, Schoepite from” the..o 33.06 150 CoNNEcTICUT chalcocite.............. 146 —egranite, Xenoliths in the Stony Greek) eis 6 esse es ee CONSTITUTION of Geological Society, Amendment of: so... ae 13 CONTINENTAL links, Possible.......... 120 CONTRIBUTION to the hypotheses of mountain formation; BH. C. An- OTEWS 20 Ak File Ok bee 61, 381 — —— vyomer- parasphenoid question ; Be von (EWene. es eee 138, 459 Cook, C. W.; Attempt to study the actual capillary relationships of oil .and-? water’... . san ee eee 100 : Capillary relations of oil and water 145 COPPER-BEARING rocks of Wisconsin.... 145 CopPrR deposits of Michigan......... 144 —-—-—-— and Bolivia compared...... 145 a southern Atlantic States compared —-— -— New Jersey and Michigan con- tPASEC. 3850 oso Shee es oie 45 —ores of Lake Superior, Origin of 100, 144 ents and precipitants of metallic 144 CORRELATION of oil-bearing rocks in Colorado and Wyoming; W. T. Lee 145 —-—the Pottsville and lower Alle- gheny formations in western Penn- Sylvania > B.C Renicks-sa eee CORRESPONDENCE between the Gond- wana system of Hindustan and Newark system of the eastern United States; W. H. Hobbs...... 2 CouNCIL of the Geological Society, Re- | 9X0) Wee 0) DENIER ry Cane tnd aiordic = > os: - COUNCIL’S report of Paleontological SOCICGY. oe sss 2 ete acs aus heel suene eee 3 Cox, ‘Guy Hz Memorial ofsseeenee 15 CRETACEOUS age and early Eocene up- lift of a peneplain in the southern interior of British Columbia and the development of the North Thompson ae trench); Wee wu WSlOW us ce gale aia ee 99, 561 — dinosaurs of beri Montana, and New Mexico: d ins. 425.00 eee 407 —of Texas and northern Mexico..... q2 CRITERIA by which to determine the di- rection of faults; Bailey Willis... 144 INDEX TO VOLUME. 34 Page CritreRia for the recognition of active faults sstephen Laber. . 22... 25. - CROSS-SECTION of the Appalachians in southern New England; B. WO OGIWOU DM ar eitacesacle evens isis; seine ee CRYSTALLINE rocks of the plains; C.N. (GROW Coe od 5 ORCS 8G ca ed 66, CRYSTALLOGRAPHY and optical proper- ties of a uranium mineral (schoep- ite) from the Congo; T. L. Walker DAKE, C. L.; Memorial of Guy H. Cox. Daty, R. A.; Harth’s crust and its evo- lution DATA on the geographic nomenclature of the southern California and Texas regions ; daar) Dio 1S 0 opengl ae Dr GOLYER, EB. - Notes on the salt domes of North ‘America LON fo tae uarelie ceheece es DELAWARE, Hisingerite from.......... Dia aa EMMANUEL, Introduction aeeeat work in France and Switz- erland DEVELOPMENT of shrinkage cracks in sediments without exposure to the atmosphere; W. H. Twenhofel.. DIAMOND mines of South Africa; C. Sine fo fslae = (eve wsa vel ew) eel 0.6 «6 os « « Ce ed IPR IZICLINE oad aia Cae ere eee DICERATHERIUM. Evolution of........ DiemvosroncH, Lhe: Burtons. 2.35... . IDNNEHIECAMINU Aba. Se see ee ed —of Cordilleran Section, Annual..... Dinosaur, New species of fi Hae MO OOM Ge sche. o.cet ag sotee a sta uses oe hs DINOSAURS not a natural order....... ree ee Montana, and New Mex- Bae ce rah ANC aH aASite ON ERUC AN ae.) ty senses DRILL-HOLES, Fusion of sedimentary rocks in 216 Gack rear NNR Sree sae Cr ee ae Pag 96, Dynamics of faulting and folding; MPL aMilerym VAULT Sere oe cle wah as ae ts aye e 5 Soe Harty Mississippian formations of the type region along Mississippi River, in JIowa, Illinois, and Missouri; ILC, TMU CON EN Serie ay ab a a a a HEARTH, Orogenic exigencies of a rotary — shrinkage 5 bei BIG RRS ae ae HARTHQUAKES, HARTH’S crust and its Sees RivAe mie Tews as) abe lee, ee 6 ee (6.0, a) wiiwife.e) is 6: te a: Ss posits JAST AFRICA, Jurassic dinosaurs of... EASTERN Appalachians in the latitude of southern New England; J. B. Woodworth (printed in this volume. under the title ‘Cross-section of the Appalachians in southern New [SIGN GEA) 0 Bese Rae ie teria eh Ama Nee Epiror of the Mineralogical TRSEVOYC LETS. Oy EYE] DV Snes wee Ea eee Epwarps. M. G.; Morococha mining GISITIC ICE 00. Paarl ge ae Sea ee ae at a nN HLASTiIc yielding of the earth’s crust under a load of sedimentary de- POSMESeioW. Di Mhamberts. 2... 62. ELECTION of Auditing Committee.. — officers and Fellows of the Min- ermlocienl Society. 8. css .e.n ce bec —-——-——-—m!members of Paleontological SSDI LE) ce, search is ere ott aay OA i .mMembers of standing mittees, PnG MEO WSHe ae isl ae oceans —— Or ordilleran section........ —-——-—-— the Society j COLOSISESH Gxt oe heel ete me ees 541 150 15 431 62 ELKO, Nevada, Oil shales at....... ane ELLSWORTHITE, New hydrous uranium columbate from Hybla, Hastings County, Ontario; T. L. Walker and AP es IParsonse is canis. cesses e 150 EMBAYMENTS and overlaps in central Tennessee; R. S. Bassler......... T32 EocENE horizons of North America.... 134 LS ColuM ia tee. pep eee site nea 99, 561 —venericardia of the west coast; Marcus Elamin aatcicrisicnet sean cree cclotene 18 EVOLUTION of Stropheodonta demissa (Conrad) in the Snyder Creek shales of Missouri; HE. B. Branson ATU Pel cS UV ELPA stsreotestroen re amet tes 134 FAULT map of California; Bailey Willis 58 HAVERING. (DymMamics “Ohare + asus cere 58 FAUNA from Alaska, Boreal marine.... 118 —of the Sooke formation; B. L. Clark An ela teaDlipi eA ON GHS 5 cate tne eee 118 FAULTS, Criteria determining direction (OB th Saclia eRe eR RRR EP an Meat were eh 144 —-for recognition of active........ 58 —of the coast ranges of California; an Cry gee WAITS 35) Sea Ss mth a Nye eS, Fe We of Geological Society, Election a (OLE Nic op ite CON ea ae Gees tee Ae 2, Fissiniry of shale: some factors con- cerned in the development; J. : WENA tee ay che trae o Cotiin ss aoe Ge a 63 Hous, EF: J., and HH: M. ROBINSON : Structural study of a part of northeast Texas with some strati- ACMI MU USeCH OMS: : tates sts f clsmens ceeheoe 70 HOLDING) DyNamiGs Of. 5 ales se oor 58 FORMATION of kaolin at moderate depths t Avia wParsonses 12 sie ne FosHaG, W. F.; Catapelite from Mag- TNO O Oviewes oe voNs eiesoed «- wcwageten <= Bites 149 FOSSILIFEROUS loess beneath tilted Galena dolomite at the border of the Belvidere lobe, in northwestern HITT OTS is eee ts the, se Shy we ik eae Ney roe oe ‘ FOSSIL multilamellar invertebrates.... 133 — quarries of Snake Creek, Stratigra- phy and correlation of faunas of.. 131 Fosstns: American rhinoceroses and evolution of Dicertherium........ 134 —— Burton “Dictyospomge. ... ....s6 . TG —:Carnivorous Saurischia in Europe. 133, 449 —:Cohoes mastodon...... oe cs AMS RARE a LOG = TOMMY OD ECV Slay lat mae cuca erelorce aes ats 133 —: Miocene beds about Goshen Hole, WW AViOIMIN CR Stee td toe eo 3 —:New genus of Pelecypoda from WES GCOS Wee ante hate aia: one ellecbete tre 118 —: New ostracoderms from Ohio..... 133 —-—species of crested trachodont GTO SAN Meee ie eo a wee ne es 30 —:Phylitic and biological development of the Ichthyopterygia........... 4638 —;Pliocene -mammals of southern (OSYTUTG 3 92 sie es ig ae er bay a 2 —:Richmond of the Cincinnati prov- LT COMP acy cate Ae) Grice eons 1a crore te 132 =; Rempleo Hill smastodon: .. 6 220... a PAT —: Vertebrates from California asphalt GKESGXOVSTI Fl Eas BR ee Sere OR eae I aa hry Me 19 pane Recent geological work in Alps LOE = eS hsr SIA -B is mais aL eps me a aS ace FRONT ranges of Colorado and New Mexico; W. T. Lee (printed in this volume under the title ‘‘Building of the southern Rocky Mountains”) 54 FUNCTIONS of the division of geology and geography. National Research pore Round table discussion of mi NG eas Sens Ar eee eee a eke Spas ee. 7o2 BULLETIN OF THE GEOLOGICAL SOCIETY Page FURTHER contributions to the knowl- edge of the Cretaceous of Texas and northern Mexico; R. T. Hill.. 72 —experiments on the fracturing of hollow brittle spheres and their bearing on major diastrophism ; W. - Bacners seen aas ie ee 81 FusIoN of sedimentary rocks in drill- holes; N. L. Bowen and M. Au- TOVESSE AU Fas a aie alae, wal ade vay autre 96, 431 GALENA dolomite in northeastern Illi- TOTS. oe ees we toeeremiel Aalst Geet ot amos 90 GENETIC comparison of the Michigan and Bolivian copper deposits; J. T. SiMLCWwaA: ALY ae ae ees cee beeen 145 GEODETIC work in the United States, SEO NN D ESA O liane Suet sy Ris Beck Ae, oars eee ete 74 GEOGRAPHIC distribution of ore deposits in Australia; E. C. Andrews..... 144 GEOLOGICAL sketch of the “Tsin-ling- shan China < Re Ri: Morse ie J scx. 119 —map of the-Bushveld complex, Trans- yyaal, south Atrica : CC. Palache...- 95 — reconnaissance in Mongolia; C. RP. GRIGG Me cahs, = Bente uencts Buchs ersien tease temo boas 80 GEOLOGY of the Alamo mining district, ; Baja, California, Mexico; C. .F. DO LIVATN Eo rc nahewe here, cueg st. at Rt ahe Tae ire 119 GEOSYNCLINE, Lake Superior......... 669 GEOSYNCLINES of North America...... ae Oe oe eat 152 GEOTHERMS of Lake Superior copper County 2A. (Co WGamesn.« toes sete oe 703 GERMANY, Triassic reptilian fauna of.. 405 GLACIAL deposits of Missouri and adja- cent districts Bi Geverettic. «sc: 91 — drainage on the Columbia Plateau; Je EPPS Betz. 4c y.e OS oils ae ole 92 ila —lake problems; G. H. Chadwick. 92, 499 GLACTATION in Alberta, Structural fea- LULEES. CAUISEG WD Vie rs ee ioe ie ee 419 GOLDSCHMIDT, VicroR, Mineralogical Society's 2rectingse tOm cn. . oh = 2 sets 149 FONDWANA system of Hindustan...... 82 GOSHEN Hole, Wyoming, Miocene beds ADOUE Hy od See olen wae Nae Sea 133 GouLD, C. N.:; Crystalline rocks of the DERVIS Se ca Sieyt bs openeo lee oe ore 66, 541 GRANGER, W., and W. D. MatTTrHeEw ; Pliocene mammals of southern Guin TaN a: teens 2 Suc fe tacts Suen ae eee 128 GREETINGS of the Mineralogical Society to Professors Groth and Gold- . SCHMUE. h sox ts eevee oe ee, ieee 149 GREGORY, HERBrRT E., Memorial of Jo- Seph ee Garreblass Ahr. eee ots 18 —:;Reconnaissance traverse from Mo- jave Uloiane, California, to Rock reels? ita Swen Rat apelin ews Cone 74 GroTtH, PauL, Greetings of Mineralog- iCal Sociehy, tOewss.- oe aaa eee A GroTon, L. C.; A source of pressure LOT OLE EOE MIA COM ~~ ate x. s eerewe eae 146 : Native copper deposits of Michigan 144 GROUP PLOtogravhy cs = a6 vee aie oes 60 Grout. F. F.; Ladder veins in Minne- SOAP Ee Pelee cya oa mse kano gee Mer oar 146 —;:Maenetite pegmatites in northern WEIN eS OTA aot tene ents SAS eee caer 146 HANN’‘, Marcus: Eocene Venericardia Of: TRE AWESEF COASbe senior hie oc as oe fous 118 Hawktns, A. C.; Hisingerite from Dela- WVATC. Men pre ete ects Grane 149 HrIDENRICH, C. P.; Restoration of MASTOD ORO ADY soe es cet ada whe a awe a bear Hewrrr, D. F.; Structure of the Spring Mountain Range, southern Nevada 89 Hitt, R. T.: Data on the geogranhic nomenclature of the southern Cali- _ fornia and Texas regions. <..5..5 > 67 OF AMERICA Page Hitut, R. T.; Further contributions to the knowledge of the Cretaceous of Texas and northern Mexico....... 72 —:Sand.rivers of Texas and Califor- nia and some of their accompany- ine phenomena: - 22.626 05%. ae Re 95 HISINGERITE from Delaware: A. C. Fhawikkinsu) esis ec oiaeck. = reap ea ae 149 HISTORICAL geology, Successful method Of; texching seGnee ed ee 67 HOBBS "W.-H: ASiatic- aTrest secre 53° —: Correspondence between the Gond- : wana of Hindustan and Newark system of the eastern United States S82 — +The’ -Asiatievarces:. 2.4 56 eee 243 HorrMan, R., and A. WANDKE; Rock alteration in contact with sul- phides at Sudbury, Ontario....... 146 HOLBROOK, LeEvi1, Memorial of........ 51 HoMESTAKE ore body-. 2... 425. 144 HopkKINsS, O. B.; Some structural fea- tures of the plains area of Alberta caused by Pleistocene glaciation. . 2,419 TWorcuHniss, W. O.: Some _ considera- tions relating to the origin and history of the Lake Superior syn- CHING 2 iy sn hae al eee 144 —:The Lake Superior geosyncline.... 669 Hower, H. V.:; Phylogeny of the genus Agasomd . ...:.. 44.22 22. eee 118 Hovey. E. O.; Aerolite from Rose City, Michigan i:s. 0.3. 2s 22 eee 97 ——, Remarks in reply to resolution by.. T7 —,retiring Secretary, Resolution of appreciation. Ofs.=...4 21.0. 76 Hunt, WALTER F., Vote of thanks to.- 87 HUNTINGTON, ELLSWortH; Problem of mild geological climates.......... 81 Hyruia, Ontario, Ellsworthite from.... 150 HyYpotHESIS of mountain formation... 381 Ice age. Keweenaw geothermal gra- dients: and. ‘the. <: 3)... eee 86 — action on inland lakes; I. D. Seott. ‘92 ICHTHYOPTERGTA, Phyletic and biolog- ical development of the...... 133, 463 IpAHO. Structure of Rocky Mountains OF esis sche) Tenis hho Shy oo a ee 5S, Zoe : atures in north- CIN ss kaw s des Se 66 IGNEOUS rocks of Ithaca, New York: 99 teaching diagram for...... 97 ILLINOIS, Fossiliferous loess in north- WeESECIN 26 css os ee eee 90 —, Mississippian formations in....... 128 —, Paleozoic rocks found in deep wells s I” ake ue em ee er eee {é . Pleistocene of northwestern....... 90 INEAND lakes, Ice action: on... 3-22 e 92 Iowa, Extinct. Lake: Calvin in Ve woes 93 : ations in*scne ee 128 IroN ores of western North Carolina.. 146 ISOMORPHISM in the silicates, Volume. 150 ISOSTASY as a-result of earth shrink- age; FY, P. Shepard.c.. . a2 eee 62 —, Layman’s. view of. ..0.... epee 57 ==, Notes of ...42-..%. 5.) eee 300 Is the channel of the Missouri River through North Dakota of Tertiary origin ?:) J. 4H. Dodds. 2 34-2 469 ITaLy, Leucite in the Alban Hills of... 150 JENKINS, O. P.: Verde River lake beds near Clarkdale, Arizona.’ Yee cee 119 JOHNSON, D. W. Rectilinear shore- lines of the New England—Acadian _ TELION Ls. bck clk ae wine eee D7 JONAS, ANNA JI., and G. W. Sto0sHE; Ordovician overlap in the Pied- mont Province of Pennsylvania and’: Maryland: << <5" ..5 fae eee 67, 507 INDEX TO VOLUME 34 (05 Page : ; : (se aee JURASSIC dinosaurs of Utah and East LEVERETT, F.; Glacial deposits of Mis- INTE CA) ch BO he ORC PERO REID ae 405 souri and adjacent districts...... 91 —, Memorial of James E. Todd....... 44 KAOLIN, Formation at moderate depths LEWIS, J. V.; Fissility of shale: some (0) Baoan YRS ae eRe Rr ORE pres 149 an concerned in its develop- fee KEITH, ARTHUR; utlines o Appa- OAKES 0 OMA Sects gee Reh 2 BPG eer eet mae ina a Hate 3 lachian structure..... Shag si se... 309 ——: Similarities and contrasts between a ieee eta ear eee ate native nee sere of New Jer- i volume under i i! Sere Sey. and of Michie’, or, oe. 45 of Appalachian structure”’)....... . 53 [LIMESTONE contact zones, High ferric wae. oe F., Memorial of Levi 51 COMMEME Of hoe as okey we chins Sets ete ae oOlbvrook ... 2... ee eee eee eee a —, Metallic sulphides in....:........ AS —; Xenoliths in the Stony Creek, Con- LINDGREN, W.; Concentration and cir- CU SEN 0 aia to eitae Ns oti 96 culation of the elements from the KENTUCKY Ordovician formations in... 131 standpoint of economic geology ; KpwrrNaw geothermal gradients and 86 Presidential address by.......... 144 the ice age; A.C. Lane.......... ° LINES of phyletic and biological devel- Keys, CHARLES; Orogenic exigencies ‘ opment of the Ichthyopterygia : of a rotary earth... ait Splish 62 FH. von Huene............... 133, 463 Kinpie, E. M.; Observations on the LockE, A.; Rock flows in arid regions. 119 range and distribution of certain Lorss in northwestern Illinois, Fossil- APE es ot Canadian Pleistocene con- 64 1 PEFO? PSU Sars MR a el Goeller tg 90 RCUOMS. s/c%- 2 sii ss Sesh te eee i ONGWELL, C.R.: ue y ; Range and distribution of certain on re i eh gh hay ra ae : es 231 paees Of Canadian Pleistocene con- 609 —:The ee nities eae Sone 2 f aO RN Eee Sat Saeed ae si recently set forth by Professor Knox, H. H.; An effect of climatic Kober, of Vienna (printed in this change on the superficial altera- volume under title ‘“‘Kober’s theory tion of ore deposits............. 146 BMGT e Sip a Sas 53 Te aad DE USE a 224 Loomis, F. B.: Miocene beds about es oa ORC OW cin lian Se ae a Goshen Hole. Wyoming.......... tieye Kraus, E. H.; pee SE Fone Louprrpack, G..D.. and R. R. Morsr: Tatus in iteac Bes Gee ye 150 Late Tertiary and Quaternary of mineralogy............./.+--. diastrophism in southern Cebu, = LADDER veins in Minnesota: Fr. F. Grout 146 Phihippimerislawtds: . 52 os seecale 59 AKE rior copper country, eo- a eer Couney, ~.. 708 Macwamer, G. W., and F. M. Van ———---—ores, Origin Of.......... 100, 144 ane pee history of the 3 Be ATMO. pee Oe ee Pa 669 oloradoshiront. dane. sts eee 87 Mine. Ovisin Ge toes Sees 145 MAGNET Cove, Catapeliite LONE sey eee a 149 LAMBERT, W. D.; Elastic yieldmg of MAGNETIC surveying on the copper- the earth’s crust under a load of rerane rocks of Wisconsin; H. R. f sedimentary deposits............. 305 Adarichy i=! ge etc te or ee 145 LANCE aeGplemn, -f * ty SOE Ae eee 71 MAGNETITE Perea ites in northern Min- LANE, A. C.: Geotherms of Lake Su- nesota ; ped ey GOULG S = Pret. aici 146 perior copper COMMUTE eso lans ro ene ic 703. MAINE: Sea-mill at Boom Beach...... 65 -Keweenaw geothermal’ gradients ANUAN? SAT GEM RIMATES Hes aia) ode Up a Ree 410 fee ice Are. os eo ea ee 86 MANSFIELD, G. R.; Rocky Mountains of —:;Solvents and precipitants in the Idaho and Montana (printed in this Michigan copper lodes........... 100 volume under the title ‘Structure —:;Solvents and precipitants of me- of er Rocky Mountains of Idaho s Met Mee CO PORT c) ces soo ite els. sits clcenac a ss. Ss 144 and OTANI) tee ae ee es Mies D3 LATE Tertiary and pieecuceme lettace ae ea eece eae Horley Mountains be lains of the middle tlantic to) aho an OMGAM ake. Pe wae eee 263 Coastal Pian (C.K Wentworth. . 91 ee Pinca \ a aly of Western ; —-—— Quaternary diastrophism in North America Bruce Clarins a. lst southern Cebu, Philippine Islands; MarTENS, J. W. C.; Study of the igne- G. D. Louderback and R. R. Morse 59 ous rocks of Ithaca, New York, LAwson, A. C.; Prediction of earth- FINES AUCTION 1 et Us a ee ee Soo 99 {OL ITE DS, SAP ee al Ae eo a ee 119 MARYLAND, Ordovician overlap in..... DOT LEAD region of South Dakota. Struc- —, Ordovician overlap in Piedmont of. 67 TuGaeteattines im pels tee. 144 Masropon from Cohoes, New York.... 127 Ler, W. T.: Building of the southern —ia. wee ae nore: ee a Pari UO Kaya a VUOT I TANTIS hs ceria ce cies 3 we a0 2 _aTTHEW .. anc . GRANGER; Woe clcition of oil-bearing rocks in Buocene mammals of southern iba Colorado and Wyoming. oo. 2... 2. 145 LEVITATSD, ek RS Se Nee tipi rat A 2§ — Front ranges of Colorado and New —:Recent progress and trends in ver- Mexico (printed in this volume pepe ae Ba Ee aLOWey» ee are “iets under the title ‘“‘Building of the AGO CSSS Dwr sic wie hota cites ) southern Rocky Mountains’’)..... 54 : Stratigraphy of the Snake Creek LEIGHTON. M. M.: Fossiliferous loess fossil quarries and the correlation beneath Galena dolomite at the Of woes AUMAS scons face a acs eee 131 border of the Belvidere lobe, in MERGING of the Carlile shale and Tim. nortowestern Gllimois:).0..5..%. 90 pas limestone roe ueag tons in south- —:Pleistocene of northwestern Illi- eastern Colorado; H. B. Patton.. > nois: a graphic presentation of : 74, 495 some of the chief lines of evidence 90 MiuMorrmn of Gity HCox: C) lie Dake. 15 LEITH, C. K.; A layman’s view of the WATE cee ee ae ata cieheeoe 44 EMEORY, (OL VISOSTASY sis a on ssolee'e. «<8 57 — — Josep arrell; Herbert E. Greg- LEUCITE in the Alban Hills, Occurrence AULRY A snr ene Weyer ice aye beh aint dae ape eye) spe/8 sn 18 DIE. Ser ouS keene dene feltch Ries age A a ce 150 — — Levi Holbrook; James F. Kemp.. 51 704 Page MerRIAM, J. C., and C. Stock; Pleisto- cene vertebrates from an asphalt deposit near McKittrick, Califor- TPA oor ie ed Ce ae ee ee ae ieee 119 METAMORPHISM of quartzites by Bush- veld igneous complex; F. E. Wright 96 Mexico, Alamo mining district of..... 119 L = \@PehaGeous Ob. oes oie ee es 42 MicuHi1Gan and Bolivian copper deposits ui CORLPALEE (= haan eee ee eee eee 145 ——New Jersey copper deposits con- PASTOR. aor ares oe rintagay aucne eee ys 145 — copper deposits compared with those of southern Atlantic States....... 145 — —lodes, Solvents and precipitants in 100 —, Native copper deposits of......... 144 2 Kine. Citys AerOute se ee = ee 97 MILLER, W. J.: Pre-Cambrian folding in North America.......".-.-- 66, 679 MINERALOGRAPHY as an aid to milling; BLS SEW ORISON SG < e ceo le a Sere ees ore 149 MINERALOGY. Use of projection appara- tS) In “teachings o. shies. 2 aS als eS ie 150 MINERALS : Appalachian bauxite de- ESEES A ee ete ere ernie ee ieee ae Coe ae MINNESOTA, Ladder veins in......-..- 146 == Magnetite PEsMatess IN. 2 cos ae we 146 MIOCENE age of the oil shales at Elko, Nevada =. 2 Buwaldas | s9- es 118 — beds about Goshen Hole. Wyoming; 8 BS LGOMmMis ek oe ste. eae 3 133 — boreal marine fauna from Alaska. 118 MISSISSIPPI River, Sedimentation at the-MOuEnS GE CHES ie cue eee 95 MISSISSIPPIAN formations in Iowa, Illinois, and.’ Missouri. . 326. os. 2-2.52 128 Mrssoturi, Evolution of Stropheodonta demissa (Conrad) in Snyder Creek Shales ob. ee ae ee os eee 134 = Glacial .depesits™encics. 2. 2a. fe Ot —., High temperature vein in......... 99 —, Mississippian formations in........ 128 — River channel through North Da- Kot OFriei GEe20e eee: oo. ee 469 Mosave Ulojane, California, Reconnais- Sance. traverse from... 225: 222.2) - 74 MoncGouta, Geological reconnaissance in 80° Montana, Cretaceous dinosaurs of.... 407 —. Structure of Rocky Mountains of.. 53, 263 Moore, R. C.; Early Mississippian for- mations of the type region along Mississippi River, in Iowa, Illinois, aTHnG - MISSOUPIAGs cle. eie er ore a ee 128 —; Quantitative criteria in paleogeog- FADHY: le Nace] canine ieee ee 85 —:Physiography of the Paria River Valley, southern Utah .s5.2-2 2... : 94 —: Structural features of the Colorado Plateau and their origin......5.. 88 MorococHa mining district: M. G. Ed- WATAS © ee Go a ee ee eee 119 Morse, R. R.: Geological sketch of the sin lne-shan- Chima. 2 eee ee 119 —and G. D. LoOUDERBACK: Late Ter- tiary and Quaternary diastrophism in southern Cebu, Philippine Is- RAGS tos Ss eee ek eg ee ee 59 MoTHER plants of petroleum; David WH he 22 in Sr ae Cee glee ny 145 MounTAIN formation. Hypothesis of 61, 381 Mount Robson Cambro-Ordovician sec- HOR foe ee Rat, cee ae ee 721 MULTILAMELLAR invertebrates......... 133 MYADESMA, a new genus of Pelecypoda from the marine Oligocene of the WES! ‘coast } 5) EB NClrks. = ees 118 NATIVE copper deposits of Michigan: Re) Gratenees eee ee eee eee 144 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page NATIVE copper deposits of the southern Atlantic States as compared espe- cially with those of Michigan; T. L. Watson: 22 oD. ees oe ae eee eee NATIONAL Research Council, Election of representative: Of..04 5. ja) ieee — ——. Functions of the Division of Geology and Geography of the.... NECEROLOGY . 2 ic. 5. 2 So os lo eee eee NELSON, We A. Geposits.. 2.20 Oe, 5 2 eee —: Origin and formation of certain Ap- palachian bauxite deposits....... NeEvabDA. Oil shales at_Elko........... NEWARK system of United States corre- sponds to Gondwana of Hindustan NEW ENGLAND, Cross-section of Appa- lachian -in. Southern... >... 5 = see NEW ENGLAND-ACADIAN region, Shore- limes’. of | the: .. = ij. ae eee NEW JERSEY and Michigan copper de- posits contrasted): 32.5.5 5 eee New Mexico, Cretaceous dinosaurs of. New species of crested trachodont dino- saur: W-. A. Parks >... .o eee — teaching diagram for igneous rocks; A. B. Van Hsbroeck.= 5 22 2.2 New York, Chemung stratigraphy western 2... 301, ou sei eo 2 eee —, Igneous rocks of Ithaca........... —., Postglacial banded clay near city of NOMENCLATURE of southern California and Texas regions, Geographic... . NOMINATING Committee of Cordilleran DeCHON Ss. cond bel ae Oe eee ——. Marine Eocene horizons of west- GFN hs ne bo ee oe en eee — —, Pre-Cambrian folding in........ Fas Yar and nature of geosynclines OF 6c oe Sa ee De ee eee ee CAROLINA, Titaniferous iron ores Of. ws awe oe oe NortH Daxkora, Origin of Missouri River channel throwsh. . 3:2 455.46 NorTH Thompson River trench, British Columbia 2 2.48 ob eee NOTES on isostasy: C. Van Orstrand the salt domes of gees America : BK. De ‘Golyer, . 3. oe eee OBSERVATTONS on coal swamps in north- ern West Virginia where Permian conditions prevail: J. L. Tilton.. — -— the range and distribution of cer- tain tynes of Canadian Pleistocene eoncretions ; B: M. Kindle=s. 2 = OccvUPRENCE of leucite in the Alban Hills: H.. S. Washinston: 2. OFFICERS and Fellows of Mineralogical Society. Election Of... 52 - eee Milection of ..... 02. 2. Pee —of Cordilleran Section. Election of.. —, correspondents, and Fellows of the Geological Societw...:. 22. eee —-—— — members of the Paleontological SOCICLY: <2 5 6.028 Sek eee —of Geological Society. Election of... —-—the Societv of Economic Geol- OIL and water, Capillary relations of. 1 — shales at Elko. Nevada............ OKANOGAN Highlands, Topography and feolory Of .). 2. %.. 2k see ee eee OLIGOCENE marine fauna from Alaska. . New genus of Pelecypoda from west coast) marine. 7 So ee eee INDEX TO VOLUME 34 Page OLIGOCENE of west coast, New genus of Pelecypoda PEOM.. <2. 6. as een oer OnvTaARIO, EHlsworthite from Hybla. 150 —, Rock alteration at Sudbury....... 146 OrDoVICIAN formations in Kentucky MG MeMIMESSCE:. ace si ccc ee wes: Uasal — overlap in the Piedmont Province of ' Pennsylvania and Maryland; G. W. Stose and Anna I. Jonas...... 67, OrE deposits, Effect of climatic change Me nie lepini allele vig \e) ele e106 «6 ‘a: 's' 4:0. 0 58. (enfe aire on a ee MTT PACT STUD) cligunieeelc ayes ie ase se) Cae. — formation, Source of pressure of... OREGON, Stratigraphy Om Leentnalic ce. se ORIGIN and formation of certain Appa- lachian bauxite deposits; W. A. : Nelson —_-——history of extinct Lake Calvin, fowa: W. H. Schoewe.....-.--.- OROGENIC exigencies of a rotary earth; ROT ATOMIC VES oe ea ssw se se = OROGENY, Kober’s theory of.......... OSTRACODERMS from Ohio, New....... OUTLINES of Appalachian structure ; Ja TELE AE 2] EOE Ce ICR REE ae eeeie yee sikepeul Lol e|se'l ale) «iets fe Leia\y@ (6 616. 4 (ea. 6,8; 5 PAIGE, SIDNEY; The Homestake orebody PALACHP, (ae ‘Diamond mines of South Pir ee es : Geological map of the Bushveld complex, Transvaal, South Africa. : Vanadium deposits of the south- west African protectorate........ PALEOBOTANICAL contributions to the stratigraphy of central Oregon; eae Calan ey 5%, ie ieds Go ales oe PALEOGEOGRAPHY, Quantitative criteria TD ca dudlecceGee Sto roca ice ce eae Rca WAG OZOLGOTLEDtLLESS. 25 5 si. eo ee eo — rocks found in deep wells in Wiscon- sin and northern Illinois; F. T. SMG CME NN eat Sees, kicc cete Oe e dae Sec e PARALLEL folds and boudinage; T. T. (OOMITTERG@ 2h a ee es eee eae Paria River Valley, ARIS Wa: A. 5 Physiography of.. New species of crested tachodont= GiNOSAUT. 20. FL. .ns 3 Parsons, A, L.; Formation of kaolin at PMAOMET ATE GEDMELS sce cis bo itehiw eckece es —and T. L. WALKER; JHllsworthite, New hydrous uranium columbate from Hybla, Hastings County, On- EMIS OME Rue ce ere ae yee se etead fa ecu he PatTron, H. B.: Merging of the Carlile shale and Timpas limestone forma- tions in southeastern Colorado. 74, 144 495 PEGMATITES in northern Minnesota.... 146 PELECYPODA, A new genus of........-. 118 PENNSYLVANIA, Ordovician overlap in Piedmont of southern......... Blo aT PERMIAN conditions in West Virginia.. 72 —faunas of Texas and South Africa.. 4038 PETROLEUM, Mother plants of......... 145 PHILIPPINE Islands, Tertiary and Qua- ternary diastrophism in.......... 59 PHILLIPS, A. ; Possible source of metallic sulphides in limestone.... 149 PHYLOGENY of the genus Agasoma; H ONE Ge Scene CER aR Can Coane CE 18 PuHysicaL history of the Colorado Front Range; Ff. M, Van Tuyl and G. W. MTF GAIT GI lea oy. cdicca cero e thal a cPeo wun lem ePen ec 87 PHYSIOGRAPHY of the Paria River Val- ley, southern Utah; R. C. Moore... 94 PLAINS, Crystallime rocks of the...... 541 PLEISTOCENE concretions, Canadian 64, pe — elteranon im Alberta... i... sass — — — —, Certain effects of......... oe —of northwestern Illinois: A graphic presentation of some of the chief lines of evidence; M. M. Leighton. 90 PYORRH@A PLEISTOCENE terrace plains of the mid- dle Atlantic Coastal Plains....... — vertebrates from an asphalt deposit near McKittrick, California; J. C. Merriam ande€. Stocker. 119 PLIOCPNE mammals of southern China: W. D. Matthew and W. Granger.. 128 POSSIBLE continental links; Bailey ATT Se: SSN Meh ee inate ate rae nape Saar emtocs 120 — source of metallic sulphides in lime- Somes Aq Seals. reeener sede aie 149 PoOST-GLACIAL banded clay near New EVO elses @uitayy sphere sen ta are coun erence epee ey ee POTTSVILLH formation in western Penn- Shy VepMat ko. woos ake alc etapece oe ear Seta ene 68 PIEDMONT Province of Pennsylvania and Maryland, Ordovician overlap THOT SF GK Sit: Pale ee ean artis, oe 1S Jaeaselgit UE My ONE 507 PRECAMBRIAN folding in North ICOM MAN See SILO 2 Seon ere. ee 6, 679 PRECIPIT ANTS and solvents in Michigan $ COPVWEMAOGESE yo aes 5 ead oe ie ea 100 PREDICTION of earthquakes; A. C. Law- SOM alice recto sa ee et eS aaeet ates 119 PRELIMINARY report concerning some new ostracoderms from Ohio; J. E. CaM wc Sew cucksek cise eet ki s ehes acne ent 133 PRESENT status of the geodetic work in the United States and the value to geology; William Bowie......... 74 — — — — Ozarkian nad Canadian sys- COMMS Ete Ore OL VCH st hoe nec eee 134 PRESIDENTIAL address by W. Lindgren, of the Society of Economic Geol- OPETISHOS) «yo auctey Ok epee na Ren Petit an Bat 144 ——-— W. D. Matthew: Recent prog- ress and trends in vertebrate pale- OMEOUNOC Veen emer ss oe ecco ose ate 30, 401 —-—-— Charles Schuchert: Sites and nature of the North American geo- Siva CTA eerste ee ors utenc e ene, Ceee 151 ———T. L. Walker, of the Mineral- OZUCAIMSOGLOTYiwe see fae oe etek aa ees Primary chalecocite, Bristol copper mine, Connecticut; A. M. Bateman 146 RN PAES ara ClaneTNT Mc. = eens crciede sie oe 410 PROJECTION apparatus in teaching min- CLAM OS VeRO Olic.cce 6 cae dures seat ee PROCEEDINGS of the Thirty-fifth Annual Meeting of the Geological Society of America. held at Ann Arbor, Michigan. Thursday-Saturday, De- ceember 28-30, 1922; Charles P. Bete ver SCLRCEOIUL. cele sulocsel x) auc oe — — — Twenty-first Annual Meeting of the Cordilleran Section of the reological Society of America, held at Stanford University, California, Avril 29, 1922; A. F. Rogers, Sec- retary —-—— Third Annual Meeting of the Mineralogical Society of America, held at Ann Arbor, Michigan, De- cember, 29, 19225 kh) R. Van Horn; SeCGreltary pro Lempore.. 25.22... — ——- Fourteenth Annual Meeting of the Paleontological Society. held at Ann Arbor. Michigan, Decem- ber 28, 1922; R. S. Bassler, Secre- ACER fs oy has REPAY Be ROR See RON EEO ESI Pa 4 —-—-— Second Annual Meeting of the Society of Economic Geologists, held at Ann Arbor, Michigan, De- cember 28-30, 1922; Sydney H. ale NIC EVELOMU use oe ei oe cnet cats PROGRESS of mineralogical methods: Be eee address by T. L. Wal- OTN OMe ZAP op SER ASN Re 2 1o a ae Ree Race ProRTEM of mild geological climates; RISworuy Eiuntine tom... <<... 81 in the Cohoes mastodon; OCMC TISONes cierto aie Stancil s Sore i) -~I 796 Page QUANTITATIVE criteria in paleogeogra- 7 phy >Re. CAMOOre Ge oe ein Sn lee 85 QUARTZITES in the lead region, South PRO Cale Shae an cs eae ee Sec te aaa ae 144 QUATERNARY diastrophism in southern re CODUEN ted. RG Sa a dee, ce tone eee 59 QuIRKE, T. T.: Boudinage, an unusual structural phenomenvon:....-.... 22: 649 —: Parallel folds and boudinage...... a9 RaNGeE and distribution of certain’ types of Canadian Pleistocene concre- tions] ‘Mis Rindle os sie. eae 609 RECENT progress and trends in verte- brate paleontology: Presidential address by W. D. Matthew... 130, 401 — work in France and Switzerland on the structure of the Alps;. Em- ¢ mamuels de WMareeniG ncn. cle ere custe er 56 RECONNAISSANCE traverse from Mojave Ulojane. California, to Rock Creek, Witah ee eee SHORELINES of the New England-Aeca- dian. region.....+.6 4 5:/) eee SHRINKAGH cracks in sediments....... SILICATES, Volume isomorphism in the SIMILARITIES and contrasts between native copper deposits of New Jer- sey and of Michigan; J. V. Lewis. SINCOSITE of ins uranite TOU, sees SINGEWALD, J. Jr.: Genetic compari- son of ee “Michigan and Bolivian copper..deposits:. 2252) 9 eee and nature of the North Amer- ican geosynclines: Presidential ad- SITES dress by Charles Schuchert.... 53, SNAKE Creek fossil quarries, Correla- tion. of faunas of <2 See SNypDrr Creek shales, Evolution of Stropheodonta demissa (Conrad) in SOME considerations relating to the ori- gin and history of the Lake Snu- perior syncline; W. O. Hotehkiss. —eriterian used in recognizing active faults; Stephen’ Taber). eee — faunal correlations of the Richmond; W... H.. Shideler:: : (ANG MELVELS Ole ena ste chorea eset aR 95 , Stratigraphic sections in northeast. 70 THE Appalachians; Arthur Keith (printed in this volume under the title “Outlines of Appalachian structure’) — Asiatic ares; W. H. Hobbs 243 —hbasal Richmond of the Cincinnati PEOvincers We be. Shidelerss + see» — Burton Dictyosponge: J. M. Clarke. 127 — Homestake orebody; Sidney Paige.. 144 — Lake Superior geosyncline: W. O. LE LO} UCIT CS Sy ahaa at RON 7 ERP ie ag na 669 — Lance problem; Freeman Ward..... 71 — problem of fossil multilamellar in- vetuebrares : ROS) Bassler. i. s 133 —theory of mountain structure re- cently set forth by Professor Kober, of Vienna; C. R. Longwell (printed in this volume under the title “Kober’s theory. of orogeny’’).....; — work of Joseph Barrell on problems in sedimentation ; Thomas Wayland Vaughan 28 YHOMSON, ELLiIs; Mineralography as aD ea On MTU MINS ES Nee. etn 149 DAOMSONLEE \COMpPOSitlon OL... oss a.) 150 THWAITES, F. T.; Paleozoic rocks found in deep wells in Wisconsin and NOTEMETMMMMOIS.6 .. 2 ce ee 73 TILTON, J. L.; Observations on coal Swamps in northern West Virginia where Permian conditions prevail. 72 TIMPAS limestone and Carlile shale. AVI O MOE Oile-a eset dee ees eee 495 EO Re OLOMACOstetcen hair eae atte ot A: TITANIFEROUS iron ores of western North Carolina; W. S. Bayley.... 146 Topp, J. E.; Is the channel of the Mis- souri River through North Dakota Cf uMerharm Origin: <2 ose a.6.28 ee! 469 SFU NO TMA NOt cs Weychap'si ame ae nant o als ts 44 TOLMAN, C. F.: Geology of the Alamo mining district, Baja California, DS RCOME eee Sl ie et hon 119 TOPOGRAPHY and geology of the Okan- ogan Highlands and Columbia Pla- teau of Washington; Solon Shedd. 75 TRANSVAAL, Geological map of the Bush- Cl Chere ORD LENE nw eel. 5 cue ita Stat 95 TREASURER’S report, Mineralogical So- CICNISY Ae raphe, oy ec ene ey a ae eg ee 148 — +L aleoniolorical Society... 2... 124 =a COMOSTCAILE SOCLELY 6 6 ie alee bec 9 TRIASSIC reptilian fauna of Germany... 405 , Saurischia in Europe since the..... 449 TROWBRIDGE, A, C.: Sedimentation at the mouths of the Mississippi River—preliminary report........ 95 — ;Tertiary stratigraphy in the lower RiOe Grande’ TELIONs: cosas ce. oo TROXELL, E. S.; American rhinoceroses and the evolution of Diceratherium 134 TSIN-LING-SHAN, Geological sketch of (EINES sg hse co ees SRCRS oa ee ae a gti ee eee am 119 TWENHOFEL, W. H.; Development of shrinkage cracks in sediments with- out exposure to the atmosphere... 64 UGctow, W. L.; Cretaceous age and early Eocene uplift of a peneplain in southern British Columbia.. 99, 561 708 Page Ubtricu, E. O.:; Present status of the Ozarkian and Canadian systems... : Relations and overlaps of Ordo- vician formations in Kentucky and TPeWNESSOC™ es. nisi os kee eee re TS HOS UMPLEBY, J. P.; Some structural fea- tures of northern Idaho.....:.... URANITE group: Autunite, carnotite, sincosite, etcetera; W. T. Schaler. of projection apparatus in teach- ing certain phases of mineralogy ; Be RTS CS. of ecexs Shel aicp eG, nase ciets UtTaH, Jurassic dinosaurs of.....- Seer —, Physiography of the Paria River Valley —, Reconnaissance traverse from Rock Creek USB mitt wget, th isi ue helo) ate Ta) wey w tote la else se) oye ve VANADIUM deposits of the southwest African protectorate; C. Palache.. VANCOUVER island; Sooke formation of. VAN ESBROECK, A. : New teaching diagram for igneous rocks.:..... Van Horn, F. R., Secretary pro tem- pore; Proceedings of the Third An- nual Meeting of the Mineralogical Society of America, held at Ann Arbor. December’ 295 1.922% ste o-. VAN ORSTRAND, C. E.; Notes on isostasy VAN Tort, F. M., and G. W. MaAcHA- MER; Physical history of the Colo- Tad0 SE TrOnt RanZe .. sore sale koe ous VAUGHAN, THOMAS WAYLAND; The work of Joseph Barrell on problems in sedimentation VERDE River lake beds, near Clarkdale, ATIZONA = (Ol P= JemMKING +f 25 ccs. VENERICARDIA, West coast Eocene..... VERTEBRATE paleontology, Recent prog- TESS /ANGSETeMdS, TNs. esc. 3 See VOLUME isomorphism in the silicates; Sear 24 Daa TA GY Es tt Ga (hehe Se emg 2 VOMER-PARASPHENOID question, Contri- PUEION TOSENG aoe Sos eile tha aks VON HUENE, F.: Carnivorous saurischia in Europe later than the Trias 133. ; Contribution to the vomer-para- Sphenoid Question 2). seu. se. ; Lines of phyletic and biological de- velopment of the Ichthyopterygia. 133, VoTE of thanks to Walter F. Hunt..... WALKOR: 7) E.. and»As Ts. “PARSONS ; Ellsworthite, new hydrous uranium columbite from Hybla, Hastings County, — ONTALIO yl dane ieorepetetonee: -; Crystallography and optical proper- ties of a uranium mineral (schoep- 1e)trom the: Conso.. 4. ease : Progress of mineralogical methods; Presidential address by. 22/2... -: 130, 133, 133, 134 150 150 405 ~ i 150 134 147 300 401 459 449 459 463 87 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA WANDKE, A., and R. HorrMan; Rock alteration in contact with s1lphides Page at. Sudbury, Ontario:.2.255. 0 146 WARD, FREEMAN; The Lance ; wvlem.. 71 WASHINGTON, Geology of Okanogan Highlands and Columbia Plateau of T75 —, Glacial drainage on Columbia Pla- beau: Of..5 ase See te ee 92 WASHINGTON, H. S.; Occurrence of leu- cite» in, the. Alban> Hilissee eae 150 WATER and oil, Capillary relations of.. aa , 145 Warson, T. L.: Native copper deposits of the southern Atlantic States as compared with those of Michigan. 145 WELLS, R. C.; Chemical suggestions concerning the origin of Lake Su- perior copper oress.-ce eee 100, 144 WENtTWoRTH, C. K.; Late Tertiary and Pleistocene terrace plains of the middle Atlantic. Coastal Plain.... 91 WeEstT Coast Eocene, Venericardia..... 118 ——, New genus of Pelecypoda from marine Oligocene Of.) .o) ae 118 WEST VIRGINIA, Coal Swamps im...... Ue WHerry, E. T.; Composition of Thom-. sonite ... 2. oo. 2 ee See 150 : Volume isomorphism in the silicates 150 WHITE, DAvip; Mother plants of petro- leum 26063 . 6. eee 145 WILLIAMS, J. S., and E. B. BRANSON; Evolution of WStropheodonta de- missa (Conrad) in the Snyder Creek shales of Missouri.o) 2-2 oo eee 134 WiLLIS, BAILEY; Coast Ranges and Si- erra Nevada. .).... co cqce eee 53 —:;Criteria by which to determine the direction: of faultsiy: =] 55s 144 —;Dynamics of faulting and folding.. 58 —:Faults of the Coast Ranges of Cali- fornia .2... i... 05 eee eee 58 —; Possible continental links......... 120 WISCONSIN, Copper-bearing rocks of... 145 —, Paleozoic rocks found in deep wells IT Foes ae oo Ske be ne 73 —, Road materials investigation in.... 146 WoopwortH, J. B.: Cross-section of the Appalachians in southern New England. :.2..2 .. 3. ee Pao —;Eastern Appalachians in the lati- tude of southern New England... 53 WRIGHT, FRED. B.; Metamorphism of quartzites by the Bushveld igneous complex 22): «s/n > © | eta 96 —:;Stormberg lavas of South Africa.. 97 WyomING and Colorado oil - bearing rocks, Correlation: 0: 24. )-1siee 145 XENOLITHS in the Stony Creek, Con- necticut, granite; J. Kemp.s22 96 THE GEOLOGICAL SOCIETY OF AMERICA OFFICERS, 1923 President: Davin Wuitr, Washington, D. C. Vice-Presidents: Wittiam H. Hosss, Ann Arbor, Mich. Wituiram H. Emmons, Minneapolis, Minn. T. WayLanD VauGHAN, Washington, D. C. Epear T. WHErRRY, Washington, D. C. Secretary: CHARLES P. BERKEY, New York, N. Y. Treasurer: Epwarp B. Matuews,. Baltimore, Md. Editor: J. STANLEY-Brown, 26 Exchange Place, New York, N. Y. Councilors: (Term expires 1923) . C. Graton, Cambridge, Mass. . D. LouperBacu, Berkeley, Calif. gi (Term expires 1924) kK. 8. Bastin, Chicago, Ill. L. G. Westcatr, Delaware, Ohio (Term expires 1925) MDMUND Otis Hovey, New York, N. Y. ALFRED H. Brooxs, Washington, D. 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