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E tna et nate . 7 SS a SS aS reves’ Se cian Rous evens Soe BULE EA TN cere OGcleAL SOLE TY OF AWS JS te. VOL. 20 JOSEPH STANLEY-BROWN, Editor a AVG 2 1910 “xhisorian instit, by > L NEW YORK PUBLISHED BY THE SOCIETY 1910 OFFICERS FOR 1909 Grove K. GILBERT, President FRANK D. ADAMS, \ Vice-Presidents JOHN M. CLARKE, EpmuND Otis Hovey, Secretary WILLIAM BuLitock CLARK, Treasurer JOSEPH STANLEY-Brown, Editor H. P. Cusuine, Inbrarian Class of 1911 GEORGE OTIS SMITH, HENRY S. WASHINGTON, Class of 1910 H. P. CusHIne, Councillors Et... B: PArron: Class of 1909 W. E. GREGORY, eR “RE, PRINTERS JUDD & DETWEILER (INC.), WASHINGTON, D. C. ENGRAVERS THE MAURICE JOYCE ENGRAVING COMPANY, WASHINGTON, D. C. CONTENTS a Page a Bibliography of the geology, mineralogy, and paleontology of Brazil; by a BaP DIS DAVIN fe ccte ise ess a sits Sc ie wishes Wiake y wioks tes iajansrs » Sle oy BR a ee aif é a Present phase of the Pleistocene problem in Iowa; Presidential address i RLS NOG ENTE) AO SAIYAN sien ctem visits oie cca Tage or aifonig trecliaie <0 i.e) oR: aeiead “eleie va, Urabe vane. @ ve 133 First calcareous fossils and the evolution of the limestones; by REGINALD mame LD ACL ad neh eae At saeenarae teearectay St e es ccc Per aca tule Sus yeh oe cpiay. ak wh SOR eee Gy epoouaNTarsliel «val weal oe ers 153 eorMeDiEy, NOt haiti, Dy) els He OIVBED sis ciamicle-cle « ocie wince sa Sie cce wisleierereleaueale’s © « 171 Trap sheets of the Lake Nipigon region; by A. W. G. WILSON............ 197 Contribution to the geology of the Silver Creek quadrangle, Nevada...... 223 Kinderhook faunal studies—V, the fauna of the Fern Glen formation; by SaavIa RSI SA a Tema NOURI ALLS ahs co tore nae oo tg a UA Ty se gM a ia aia carsebie ole (ohio) Sel eh suck akeveb oh OiotoRe sina 265 Shortage of coal in the northern Appalachian coal field; by I. C. WHITE.. 3383 Penian mammatian fauna; by SAMUEL CALVIN... 0050005 c cece ecco es 341 Unconformity in the so-called Laramie of the Raton coal field, New Mex- a aBPamOTMMRN ND ISTHsIOnTiS uno ae NEES otetierey te Sr a an re! a! ord, ofa aera’: a ote. 9 6 Gls: esol. ava & ohsbin.e avers 357 Proposed classification of crystals based on the recognition of seven funda- Mienitainty pes, Of Symmetry > by C.K. SWARTZ 6 < so. casi cele sebee oe es 369 Aftonian sands and gravels in western Iowa; by B. SHIMEK............ 399 Striations and U-shaped valleys produced by other than glacial action; Sp NOY SLED Nara os pa tos op ak Sieh a iG rahe tsa) Wi wie etahe ie iol eta aeeak Meigs) Slave coved wre eee ® 409 Clearing out of the Wallibu and Rabaka gorges on Saint Vincent island; SRE PED CET OWEIG 5 1c. )uro cite & 4 clase, ets > .5- eee 633 Glacial waters west and south of the Adirondacks [abstract] ; by H. L. FATRCHID. .... 2.00 dees cies oe ele ei + ee 633 Correlation of the Hudsonian and the Ontarian glacier lobes rab: 2 stract]; by H.-L. WAIRCHILD...2.%. 325.26. - a0 6 ee 634 Pleistocene geology of the southwestern slope of the Adirondacks [abstract]; by WILLIAM-3S. MULGERO..... cco). 32. eee 635 Weathering and erosion as time measures [abstract]; by FRANK LEVERETT sss 'e0c0.5 00d oc o5 lee Bid erate eele eke eee eee ore a isi erate 638 Glacial phenomena of southeastern Wisconsin [abstract]; by WILLIAM Co ATHENS...) ae eee eee «seeks oo eee “ese 638 Criteria for discrimination of the age of glacial drift sheets as modified by topographic situation and drainage relations [ab- stract].; by WILLIAM C. ARDEN...225..2-5.....-5eee oe 6388 Lake Ojibwa, last of the great glacial lakes [abstract]; by A. P. COLEMAN .oeiseas se cec os oa nie tye wien bases bo aie eee cee ..- 689 Glacial erosion on Kelleys island, Ohio; by FRANK CARNEY..... . 640 Chalk formations of northeast Texas [abstract]; by C. H. Gor- DON oes 0.0 ass oe aieilemle eneloop wey te atone ee eicetey a atest 645 Results of a recent investigation of the Coastal Plain formations in the area between Massachusetts and North Carolina [ab- stract]; by WILLIAM BuLEOCcK CLARK... .- 6 eee ‘a Geologic relations of the Cretaceous floras of Virginia and North Carolina [abstract]; by Epwarp W. BERRY...........--.:sse8 655 Report of Committee on Earthquake and Volcanic Observations.. 659 Use of “ophitic’ and related terms in petrography; by A. N. WINCHELL * jo..002 2 ee eee eee wee esse ees oes SO Chemical composition as a criterion in identifying metamor- phosed sediments [abstract]; by Epson S. BASTIN........... . 667 Tertiary drainage problems of eastern North America [abstract] ; ; by AMADEUS W. GRABAU.). .22).t2%-5 30sec ee eee eee és ose ee Drainage evolution in central New York ‘Tabstristi : by H, L. BATIRCHIED |... ss da da cade nie eee eee ee eee Perr oo: Nantucket shorelines, IV [abstract]; by F. P. GuLiiver......... 670 Iron ores of Maryland [abstract]; by JosepH T, SINGEWALD, JR... 671 Quartz as a geologic thermometer [abstract]; by Frep E. WricHt and WB. S. LARSEN. .1.... 22.2555 390s a2. ee Occurrence of the Magothy formation on the Atlantic islands [abstract]; by ArTHUR BARNEVELD BIBBINS..........ccecce -. Giz Erosion intervals in the Tertiary of North Carolina and Virginia; by BENJAMIN L. MILLER Character and structural relations of the limestones of the Pied- mont in Maryland and Virginia [abstract]; by Epwarp P. MATHEWS and J. S. GRASTY....... Sen Gee 5 Sirens ane ete .. eS CONTENTS AND ILLUSTRATIONS Recurrence of the Tropidoleptus fauna in the Chemung of Mary- DG HM yan OEIUAR RS Un Ire SWEAR Nienstaneistsvscysiehe ssieicrgia s oanate ccs aes 6 8 Geological distribution of the Mesozoic and Cenozoie Echino- dermata of the United States [abstract]; by W. B. CLARK and YES NG” MCA AU Ole TOUTES jicretn eens cee GIetG Cucina See Orne Te Gas aan ae ee -Age of the Gaspé sandstone; by HENRY SHALER WILLIAMS....... Brachiopoda of the Richmond group [abstract]; by AucusT F. ERGWR'S BH Bie cere se escasan roles poten cue naa eMee cho teil heotrate: aitroneee aid ve eh eceueea aes Reconnaissance in Arizona and western New Mexico along the Santa He catroad, [abstract iby N. El. IDARTON:....025... 00. Geologie studies in the Alaska peninsula [abstract] ; by WALLACE VN OAS TWO OD barat setae eee: ester rave) eIRNSeOel (os ah gt ala era nabaliar ehign t.wi's' is Slave e's race, wills Some features of the Wisconsin Middle Devonic [abstract]; by ELF Hoge @ TUPI AUNT i otsuerd ice pate cote vanes cu olel ee cena ateiay ous eure aves, axe ie whet araue ewe aie: Ice-borne boulder deposits in mid-Carboniferous marine shales Abstract) bys JOSEPREE Acts AH cits sos ciisiisvene, eto) apaliaie a oo oct tele wel s O6%s Relationships of the Pennsylvanian and Permian faunas of Kan- sas and their correlation with similar faunas of the Urals [ab- Size Cal nO Veveds CNN ees EW BESDDEY opcnens: sass oie varel of taerte er hc leie: er o-nils) ones ve eo a Nineteenth Annual Report of the Committee on Photographs..... Titles of papers presented before Section H of the American Asso- ciation for the Advancement of Science...............00ecees iecister of the Baltimore meeting, 1908. ..c.c. ccc. sce eeeescces : Sessions of the Cordilleran Section, at Stanford University, Califor- nia, Wednesday and Thursday, December 30 and 31, 1908......... Titles of papers presented before the Cordilleran Section........ Proposed form of seismograph intended to give a direct indication Of the toreces [abstract|:s by W. EB. DUBAND. 2.2 02..5 0.050020 650 Accessions to the Library from November, 1908, to October, 1909......... Mision otmcers, Correspondents, and: Wellows... 0... ccc. 0cccccsec sees an O me VOMIMNEs 20s 4c: aca ars, a cate.or sale We anevaheue sia i eka afretesrelers a's eoare re clete or 3. 6 Sie ILLUSTRATIONS PLATES Plate 1—Catvin: Glacial phenomena at Afton Junction and in Tama COUT O Wien tree are ara res chsh clisy susie One, a¥eyorale.s saree o.6iaoe ie 2 ie Glacial phenomena near Missouri valley and Oel- WEIN PLOW alii cc cite ce ed cele are, Veja cvausua\eiaidieie SAS vareiieisce ae ry 5° Glacial phenomena near Thayer and Missouri valley, MONE evercnere (opsser ate) Shee ec cee re eect ao eusiSue Madi eke srereve we 6 i 4 - Glacial phenomena in Buchanan county, Iowa....... a 5 3 Glacial phenomena in Cerro Gordo and Palo Alto coun- TEKS, SUIGMYEL 'G.6 Shao orb Cleon hero RSt cae eae 6—TurRNER: Rhyolite-tuff and single cone...................008 ae ‘4 - CANCALEOUS PAUPENK-SCHISE yaa sre cee klk 66s eece we wate labels % 8 s Terrace of early Pleistocene detritus east of Fish IDBURG) AGNES SSS om Gob oa ae eee IR resicic.c as 9 ef Fault wall and bedded volcanic rocks, Silver Creek EAN LOM eee erect be dee wine oe owlawles Savntornte Vv. Page v1 Page Plate 10—WeELieR: Fern Glen fauna...........--. os ba) berber 327 soe stata [| s Fern Glen fatinad. 66. io. aes. Cen ee eee s 6 ols eee 328 “42 fe Fern Glen ‘faunas 25. o2es oe ese 2 cs ar one ee 329 rapa Medes Fern Glen fauna... 6006050. c. 82. a ope gem af Fern: Glen faunal... 0.0. cess cere oe 01 331 en ef Fern Glen fauna... fo. 2. scene cscs +s ve = een 332 “« .16—Catvin: The Cox and Peyton gravel pits........).. 3.2 342 oa aaa LT s Teeth of the Gladwin: horse: 2.5.05... 0. ose 3438 faa Mie! fro | . Superior grinders of Equus scotti Gidley............. 344 a VO “ Inferior cheek teeth of fossil horses................. 346 tie”) es Much worn molars and pre-molars of Hquus compli- catus Leidy .. 6.3.6 eed. wn Sh cate a cle ete eee 348 hehe 0 oh Fossils of Hquus complicatus and camel............. 349 He ee es Fossils of ruminants... 002 5.2.22... ae Cee 350 pee oy of Fossils of ruminant and Hlephas primigenius......... 351 ey. DA : Molar of Hlephas imperator. ... 2... +252). 7 ee 852 Sc Ne 13: “ Fossil bones from Aftonian gravels................e- 353 ie 26 a Superior, lateral, and inferior views of claw of mylo- COM os aa Ge Soles ate ae eee ele ee tec oie ete ee 354 rh Nh a: Molar of Mammut mirificum Teidy........----eeee 355 ‘“« 28—LeEE: Sections of coal formations of the Raton field, New Mexico 362 “« 29 “ Hogback in Vermejo canyon, New Mexico............... 368 ai, was “Cliff near Carresso creek and cliff north of Red River peak, New Mexico... s. 00. .5 i256. eo oo oe ee ee 364 “ $i—Swarrz: Classes of crystals: 2 25.5... io. 2s. ene) oe nee ee 398 lg 3 1} us Classes of crystals os coin es Oe bees oe ee 398 “ 83—-SHIMEK: Cox pit east of Missouri valley, Iowa............... 401 eo he County-line exposures of Aftonian, section 5, town- ship 81 north, range 44-west......7.2:.. 2. eee 402 Sao s Sections showing position of Aftonian.............. 403 oh BG sS McGavern pit, south of Missouri valley, Iowa....... 406 sper Se Exposures showing folded Aftonian gravels.......... 407 “ 38—Hovey: Volcanic sand-blast action on mount Pelé............. 410 39 < Volcanic sand-blast action on mount Pelé.............. 412 a AO oe U-shaped rock gorges of the Soufriére............... 414 ian”: 5 £5 U-shaped gorges of the Soufriére..................-- 415 inh of Gorges of the Soufriére, Saint Vincent........... ase sata: 3 ¢ Wallibu gorge, Soufriére, Saint Vincent.............. 418 pai: Gorges of the Soufriére, Saint Vincent............... 420 seme - Rabaka river, Soufriére, Saint Vincent............... 424 “ 46—ScHvUcHERT: Limestone quarries near Buffalo, New York, and Louisville, Wentucky....4.426.5 40-2 . 441 i AE Quarry face at Newsom, Tennessee...........0. . 442 aa: X~ Continental seas of Paleozoic time.............. 447 oY AS . Paleozoic positive elements............... aie ease 464 a BO eS Explanation: of symbols: 225... ooo eee 606 eee) | x Upper Georgie oo soak eee ee ee eee 606 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 52 e Wpper *Acatlie’ Sot Sood sce oe eee ee ee 606 ILLUSTRATIONS V1l Page Pilate 5o—SCHUCHERT: Bower OZarkie si... 6. eect wees ces veseneccecss 606 a: _ Canadic (Middle Beck antowan) se Oe A ea ear ae 606 OO. "4 CaAmaAdiGe Gs aimMb Ve CLE ie wlovscs aics se siece se was ace eves 606 st 6 P Middle Ordovicie (Middle Stones River-Chazy)... 606 esas 9 16 = Middle Ordoviciec (Lowville)..............0.005. 606 int ae x Middle Ordoviciec (Lowest Trenton)............. 606 oe Do eo Middle Ordovicic (Late Trenton)............... 606 re 6O a UWppeemOrdovicie sa (WitiCae 2. ees cack sect ele ws 606 poe Gal! “4 Cinemmahie= (CMOrrainme)) <6 esse ccs wise sie a o's eeevers a 8 606 Se a ay4 i Cincinnatie: (mate, Richmond) ce... Ss.5 cece sce st 606 Ta 653 i Lower Siluric (Upper Medina-Edgewood)....... 606 “64 * Lower Silurie (Ohio” Clinton)... cc. ess ca cee es 606 a Ee. ef Lower Siluric (Waleott-Williamson)............ 606 7 OG ‘“ Middle Siluric (Rochester-Osgood)............8% 606 ee OL i; MiddlessSilurie, ‘Ououisvilley. oo. ov ae. ceive ee BE 6U6 Eh 108 % MinlalemSilirice, (Gwelplaiyit.. c cweesc sicrsraerecsle ceo ees. 2 606 fo 69 ay Upper silunie? (Mower Salina)... 2.3.6.2. sede ne 606 ane) * WpperiesuhaTe (CBELGIG) hari vei ile avec ives ee cae scecete: = 606 pee ak at Upper Sitlurie (Lower Manlius)... .c002 56 s0 e's 606 een @- + Lower Devonic (New Scotland)..............ee. 606 4 aalar f3 Lower. Devonie CBecratt)... 26 oo. 's 5 ee sew ewe ee 606 an (4 7 Lower Bevonic’ (Decewville) 2... 0.5 oc ces eco e's 606 sen 3) ‘ Middle Devonic (Middle Onondaga)............. 606 om LG Middle Devonie (Late Hamilton)............00. 606 ee SET - Upper Devonic (Ithaca-Chemung)............... 606 a) OG ‘ PEO ETE car eee Petey ed O'45) eigy aS gues -e-k re) 4.0) a. sim oeoteeells 606 ee OC “ VOPR OY CSIP, CO NIO CES Oar, See Er Py Oe at 606 8 oe Tae VITO CE TNT es 5 elses orla Siosv ian 6 the, wre eroeaareey 606 Byes (QO ss WME MTOCEMC erste s Gis tec ack s o'S xibiel dieescrstene atetcia's 606 Vill BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page Plate 100—ScCHUCHERT : PHOCENE on sie eis ccd sin) cine oc ae 6s oe ele 2a eel oe 606. core LO . Curves showing the amount of submergences and emergences in time and space................ 606 “<.. 102——-Hovry: Portrait. of Homer "ER. Muller. .occccr. 2 sae eee 617 *. J0O3—MeERRILL: Portrait of W. S.. Yeates. ...6.2...5.2-. +s. =e 618 “ -104—-MILLER: Map showing remnants of former connection between eastern and western Kentucky coal fields......... 621 “ 105—Van Horn: Landslide in shales at Cleveland, Ohio. ........ 625 ae OG ss Later view of the scene of Cleveland slide........ 627 ete SC) a . Anticline produced by buckling of the shales at the base of the landslide at Cleveland, Ohio.... 628 ** 108-—CARNEY: Glacial phenomena on Kelleys island................ 640 ie HOD 7 Glacial phenomena on Kelleys island................ 642 ae tO 3 Bulging on a grooved surface on Kelleys island, Ohio. 644 * 111—CLarRK: Comparative columnar sections of Atlantic coastal Plain LOrmatvions, se wide ews ars ee aaeie Soe «so oe ee 646 FIGURES REID: Figure 1—Displacement. at a. fault.......<.0..t<-. .2.0ssse eee 172 “« 2—Intersection of two planes: :.:.....2..4.....+.-.2. eee 174 ‘* 3—Intersection of a-line and a plane......-....:...2 seen 175 “ 4—Plane determined from three points..............ccee0. 176 “«“ 5-—Repeated -strata-wik-. <02.s2e.26. enin Se 86 a sa oo ee 179 ‘- .6-—Missing «strata 2c oo ee cc es So a Se ee eee 179 “ %—Determination of the shift—Case I..................6- 181 ‘“ 8—Determination of the shift—Case II............. one 182 “ 9—Determination of the shift—Case IV................... 184 “ 10—Determination of the displacement of a plane—Case V.. 185 “ 11—Simple rotation: 34 2.0ePssecd f. 2e eee Oe eee eee 189 “ 12—Rotation and translation. ..:9¢ 24022. ose eee 190 WILSON : Figure 1—Sketch plan of lake Nipigon basin................eeecee 199 “ 2—Section on Spruce river 10 miles southwest of Black Sturgeon Jake = .0...6.'5.05 he ee 204 “« 3-Section at Red rock at the mouth of the Nipigon river.. 208 “ 4—Diagrammatic section near the extremity of the point between Big Front and Pigeon bays...........c.c.e-eee- 212 TURNER: Figure 1—Map of the vicinity of Silver Peak range.......... «sae ee LEE: Figure 1—Key map of part of northern New Mexico, including Raton’ coal: ‘field. . 62... 0 50% ws Sea oe. eee 358 SWARTZ: Figure 1—Singular axis with four lateral axes................... 372 “« 2—Repetition of singular axis about oblique axis.......... 372 ‘“ 3—Trigonal axes developed by equal rectangular axes..... 372 ILLUSTRATIONS 1X Page SWARTZ: . Figure 4—Axis of symmetry developed at intersection of symmetry TOBNOSS 2.586 %5'5.g18 8.0.5 tas GiOlg CIES CIR ENC Ne ts ie tena sae a ea 372 “ 5—Alternating axis developed by alternating axes and sym- TINE Tiga S ee teor che tal cl lous eltecenereclic suctni tt aislial Wlevelv ance wie aoa 372 RE = ACNG LUCAS S ier. ror casie gyaceesarecars/ one Muse Sikle Ge Saree e Sw alele s 6 374 peer E ONApXel AML AG Sw ralere Were ave os, ic) o 4 Bier etalevel wuss eae eco @ so 6 wes as 374 eS —— OT 110 AXA AEM CLASS © cyte a nicncynersicneee a isis ore! cue Wale ae eles dbers a ests 374 ‘““ 9—Repetition of singular axis by oblique plane of symmetry. 374 seem MCAS AN ee LES Seles ra oho ay teaie sce, as. a) 10) cio oceseteuale era's 0) bie te siaie a) ous 'ee 374 seed elt) -— OP Tots AOAC TIN CLASS! svn ewarici eres 0.4 oc'nj's esi elo: eee) vi e'els, a0 e era cles wwe 0.8 376 eet AIMED MCC Aly: CLASS, nvecerSicc hiepe sn cpelel oiepe svetereis- elonevere everbsecerose 376 euenmilics = NCANG [ppxel PI CLAGS ex sence s tobeva Gia. ov Wioterare onaverore avelsseu +o ctee wees 376 “ 14Three-fold alternating axis producing orthohedral sym- HLT Ua an MTP Pe Nees cot at erat gay che icici) ate cis ie, Ss oaatotare See Sis 376 CARNEY : Micure 1——Melleys’ island, OO.) 5. occ ecc crm csc sere cc es eases ne eee 641 SWARTZ: Figure 1—Sections of Jennings formation, western Maryland...... 681 DURAND: Figure 1—Proposed form of seismograph..............cceeeeeecs 709 (111 plates, 35 figures) x BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA PUBLICATIONS OF THE GEOLOGICAL SOCIETY OF AMERICA REGULAR PUBLICATIONS The Society issues annually a single serial octavo publication entitled BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA. 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THE PUBLIC. Bibliography of the geology, miner- alogy, and paleontology of Brazil. SAO. BRANNER 4 be-cvees class Fels s 1-132 eats sates 1.40 2.10 Present phase of the Pleistocene problem in Iowa. SamuE. Cat- BING ie cries i wc a cis Raee ee ant 133-152 1-5 Eas .30 45 First calcareous fossils and the evo- lution of the limestones. R. A. : LUSTUSE. Ps SRR 2 2 cae aes oe 153-170 sitet mre .20 730 Geometry of faults. H.F. Remn... 171-196 meee 1-12 25 30 Trap sheets of the Lake Nipigon basin, A. -W- Gs WALSON ... .&.... 197-222 Saat 14 .20 .30 Contribution to the geology of the Silver Peak quadrangle, Nevada. EY ORURNER: . oe 2s 204 ooo k oe 223-264 6-9 1 .50 78 Kinderhook faunal studies: V, The fauna of the Fern Glen formation. “in| OVO 01 0) sage te ee 265-332 10-15 an .80 1.20 Shortage of coal in the northern Ap- palachian coalfield. I.C.Wuirr. 333-340 Rois aes .10 15 Aftonian mammalian fauna. Sam- MUR OANGV UNG sche sf cso be oss Be nals 341-356 16-27 ee: 00 75 Unconformity in the so-called Lara- mie of the Raton coal field, New Me atCOs WL. WER. eee ie iye3 357-368 28-30 1 .20 .30 Proposed classification of crystals based on the recognition of seven fundamental types of symmetry. BEAR SW ABT Zico 5 ohio ace oie vs Sek 5 369-398 31-32 1-14 .50 75 Aftonian sands and gravels in west- ero lowa. 5. SHIMBK «ts... + sis 399-408 33-37 eles 25 30 Striations and U-shaped valleys pro- duced by other than glacial ac- tones —H1.'O), OVE 8543 65 oes 409-416 38-42... .20 .30 Clearing out of the Wallibu and Ra- baka gorges on Saint Vincent island. BO. Howaay j,i ce55.. 2. 417-426 43-45 ree: 20 .30 Paleogeography of North America. SS SCHUCHERT 5. sino om os ve ee oy 427-606 46-101 eae 2.00 3.00 Proceedings of the Twenty-first An- nual Meeting, held at Baltimore, Maryland, December 29, 30, and 31,1908. E.O. Hovey, Secretary . 607-749 102-111 1-3 1.80 2.70 IRREGULAR PUBLICATIONS In the interest of exact bibliography, the Society takes cognizance of all publi- cations issued wholly or in part under its auspices. Each author of a memoir receives 30 copies without cost, and is permitted to order any additional number at a slight advance on cost of paper and presswork; and these separate brochures are identical with those of the editions:issued and distributed by the Society. Contributors to the proceedings are also authorized to order any number of separate Xi PUBLICATIONS copies of their papers at a slight advance on cost of paper and presswork ; but such separates are bibliographically distinct from the brochures issued by the Society. The following separates of parts of volume 20 have been issued : Editions uniform with the Brochures of the Society Pages 1-182, 200 copies. February 12, 1909. ‘183-152, plates 1-52 130° March 18, 1909. ‘€ 153-170, 300, 7 April 3, 1909. 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X1ll Xlyv BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA CORRECTIONS AND INSERTIONS All contributors to volume 20 have been invited to send corrections and insertions 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 1, line 2 from bottom ; for ‘‘glad to have’’ read glad to leave ‘¢ 37, line 20 from top; for ‘‘1822”’ read 1882 ‘* 60, line 7 from top; for ‘‘ Halfield”’ read Halfeld ‘‘ 67, line 17 from bottom; for ‘‘ X VIL” read X VIII ‘“« 72, omit second Katzer title on ‘‘ Phytopaleontologie’’ ‘‘ 98, line 26 from bottom ; for ‘‘ Petro’’ read Pieto ‘¢ 180, line 20 from bottom; for ‘‘ Belonstomus’’ read Belonostomus ‘* 180, line 18 from bottom; for ‘‘ Rhacolepsis Alfersii’’ read Rhacolepis Olfersi ‘* 130, lines 16-17 from bottom; for ‘‘ Rhacolepsis’’ read Rhacolepis ‘* 130, line 15 from bottom, for ‘‘Cladacylus”’ read Cladocyclus ‘* 160, line 20 from bottom, for ‘‘cimpilation’”’ read compilation = ‘¢ 196, insert footnote: A further note on the geometry of faults will appear in volume 21 Page 350, line 7 from bottom; for ‘‘ plate 21, Heuee 2, and plate 22, figure 1,’’ read plate 21, figure 1, and plate 22, figure 2 Page 350, last line ; ee ‘‘plate 22, figure 2,’’ read plate 22, figure 3 “¢ 372, invert fet: 4 ‘¢ 375, line 11 from top; for ‘‘axis”’ read axes ‘* 380, insert footnote: * The absence of planes of symmetry (vertical as usually held) in the simple pyramids of the axial classes is not always apparent to the stu- dent. It is recommended to use drawings and models showing combinations of pyramids of several orders, when the absence of such planes of symmetry becomes at once apparent and the distinction between the symmetry of the axial and hedral classes is clearly seen. oe 380, line 11 from top; for ‘‘ plates I and IL’’ read plates 31 and 32 381, line 10 from bottom, for ‘‘rotation. In the”’ read rotation, in the ‘¢ 381, line 5 from bottom ; for ‘‘axis—producing”’ read axis, producing ‘< 385, line 20 from top ; ae ‘“Tt is elementary ” read It is simple ‘¢ 388, line 2 from top; for ‘‘un-”’ read uni- ‘¢ 422, line 21 from top; for ‘‘ indicate’’ read indicated BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 1-132 FEBRUARY 12, 1909 BIBLIOGRAPHY OF THE GEOLOGY, MINERALOGY, AND PALEONTOLOGY OF BRAZIL* BY JOHN C. BRANNER (Presented by title before the Society December 27, 1905) CONTENTS Page MCA MICEME Te ttre een ces cite Tel tere cls “ace Gees a bate oS weleld Geet Ck SO oe ee Oe ee if POST ADIY J 2.15 0 sic deisel asecus ee Maret bes Seay avec nis, cistainoses OS or anG ieaittanet ck extieierarenets 3 INTRODUCTION No comprehensive bibliography of the geology of Brazil has hitherto been attempted. M. de Margerie, in his Catalogue des Bibliographies Géologiques, published in Paris in 1896 by the Congrés Géologique Inter- national, mentions six papers upon geologic subjects, each of which con- tains references to Brazilian geology; but none of these lists makes any pretense of being a bibliography of the geology of Brazil. In 1881 the Bibliotheca Nacional, at Rio de Janeiro, published its important Catalogo da Hxposicao da Historia do Brazil in two large volumes. One of these volumes contains a list of the books and papers in the Bibliotheca Nacional that relate to the geology of Brazil, and included in this are many titles of works belonging to private individuals and not belonging to the library at that time. That is the nearest approach that has yet been made to a bibliography of the geology of Brazil. The list was necessarily imperfect ; omitting the manuscripts and papers upon mineral waters, it contained only one hundred and twelve titles. A bibliography of the Mesozoic invertebrate paleontology of South America is given on pages 3 to 6 of Dr C. A. White’s Contribuicgoes a Paleontologia do Brazil, published at Rio de Janeiro in 1887. That list contains twenty-four titles. *An incomplete edition of this bibliography was published in the Archivos do Museu Nacional do Rio de Janeiro, vol. XII, in 1903. The proofs, however, were not seen by the author and many serious errors were overlooked by the printers. The great num- ber of titles added, the corrections made, and the growing interest in the geology of Brazil have encouraged the Geological Society of America to publish the present list. Dr M. A. R. Lisboa, one of the ablest of the younger Brazilian geologists, has now begun the publication of an annual annotated bibliography of the geology of Brazil in the Annaes da Escola de Minas. 'The author is glad to have future work on the subject in his able hands. I—Butu. Grou. Soc. AM., Vou. 20, 1908 (1) 2, BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL In 1901, the Bureau of American Republics published at Washington “A list of books, magazine articles, and maps relating to Brazil, 1800- 1900,” prepared by P. Lee Phillips, 8°, 145 pages. That list includes many titles upon geology and geography, but these articles are not distin- guished from others, and, so far as they relate to geology, there are more omissions than titles. The present bibliography contains over 2,000 titles, not counting ab- stracts, notices, and reviews. Owing to the poverty of literature upon the geology of Brazil, many books of travel and exploration are included that make no pretense of being works upon geology, but which contain notes upon the subject of more or less value. But though the number of titles is over 2,000, the bulk of them treat of the geology of Brazil only at second or third hand. The original papers from which most of these references are taken were written by a few men, the most important contributions being made by Agassiz, Clarke, Derby, Eschwege, Gorceix, Hussak, Lund, Rathbun, C. A. White, and Woodward, while the field work from which these results have been obtained was done by still fewer. Some of these men have also done a vast amount of work in cognate branches of science. Lund, for example, worked on zoology and botany, as well as on geology; and the papers of Liitken, Rheinhardt, and Warming on botany and zoology are the direct outcome of Lund’s work in Brazil. This list emphasizes the fact that the great bulk of the geologic work in Brazil has been done by two men—Eschwege and Derby. These men are noteworthy both for the amount and the character of their work. Eschwege’s results were mostly published in German, and have therefore not been as accessible to Brazilian students as if they had been published in Portuguese or French. Fortunately the results of Derby’s work have been published in Portu- guese as well as in English, and his influence upon geologic work in Brazil has been correspondingly important. Moreover, Derby’s influence has extended even further than the long list of his valuable papers would indicate, for almost every modern writer upon the geology of Brazil has been inspired by Derby’s work, and not a few of them have based their conclusions almost entirely upon data furnished by him. Mr Henri Gorceix, for several years director of the Escola de Minas at Ouro Preto, has also done much to arouse an interest in the mineralogy of Brazil and in mining engineering. Several of his students are now among the most active and efficient workers on the geology of the country. The present bibliography is chiefly an author’s list arranged alpha- betically. When there are several titles credited to one author, they are arranged chronologically. ABREU—AGASSIZ 3) BIBLIOGRAPHY ABREU E LIMA: See Lima. : ACAUA, BENEDICTO MARQUES DA SILVA: Relatorio dirigido ao Governo Imperial em 15 de Abril, de 1847, pelo Inspector Geral dos terrenos diamantinos da Provincia da Bahia. .Revista do Instituto Historico, 1847. IX, 2a edicio, 227-260. Rio de Janeiro, 1869. Parte segunda: da de- scripeio dos terrenos diamantinos, 247-260. Extract in Diccionario geo- graphico das Minas do Brazil por Francisco Ignacio Ferreira. q. Vv. 209-217. Rio de Janeiro, 1885. ACCIOLI DE CERQUEIRA E SILVA, IGNACIO: Corografia Paraense, ou descripeio fisica, historica e politica, da provincia do Gram-Para. 8°. Bahia na typografia do Diario, 1833. Mineralogy, 5-6 and footnote; pororéca, 69-70. ACCIOLY, JOSE BITTENCOURT: Memoria sobre a viagem ao terreno nitroso. Manuscripto, IV, 222-251. Inst. Hist. e Geogr. Braz. (Serra dos Montes Altos entre Urubt e Caitithe. ) ACKERMANN, EUGEN: Die Gold-Industrie an der Grenze des Staates Para im nordlichen Brasilien. Chemiker-Zeitung, XXV, 25-26. 4°. Cothen, 1901. ACUNA, PADRE CHRISTOVAL DE: Nvevo desevbrimeinto del rio de las Amazonas. Al qval fve, y se hizo por orden de su Magestad, el ano de 1639. 4°. 46 ff. En Madrid, en la Imprenta del Reyno, 1641. Oro f. 26; minas f. 27-28. The original edition is very rare. Translated into French under the following title. ACUNA, CHRISTOFLE D’: Relation de la Riviére des Amazones. Traduite par feu M. de Gomberville sur l’original Espangnol. I, 200 pp.; II, 218 pp. ~ 12°. Paris, 1682. Translated into German under the next title. ACUNA: Bericht von dem Strom derer Amazonen. 8°. Wien, 1729. Trans- lated into English under the following title. ACUGNA, CHRISTOPHER D’: Voyages and discoveries in South America. The first up the River of Amazons to Quito, in Peru, and back again to. Brazil, performed at the command of the King of Spain. Done into the English from the originals, being the only accounts of those parts hitherto extant. 8°. London, 1698. Mines of gold, silver, ete. 81-83; 131-133; 176-169 bis; 175 bis; 176 bis. ADALBERT OF PRUSSIA, Prince: Travels of His Royal Highness, Prince Adalbert of Prussia, in the south of Europe and in Brazil, with a voyage up the Amazon and the Xingu. Translated by Sir Robert H. Schomburgk and John Edward Taylor. 2 vols., 8°. I, 338; II, 337. London, 1849. The Brazilian portion begins in vol. I, 211, and extends to the end of vol. II. It contains notes on the character of the rocks. AGASSIZ, L.: Recherches sur les poissons fossiles. t. II. Neuchatel, 1833- 1843. Amblypterus olfersi Ag., II, p. 4. On page 303 he says it is of ‘“Zech- stein” age. II, p. 40, from marl shales of CearAé. Semionotus spixi Ag., from Brazil. t. II, p. 8. Semionotus bergeri Ag., II, p. 226. On page 304 8S. bergeri is put down as “Lias.” Aspidorhynchus comptoni Ag., from’ South America, by Gardner, and from Pernambuco. II, p. 139 (to be described). On p. 166, A. Comptoni is said to be from the “Craie.” Rhacolepis latus, R. buccalis, R. olfersi (= Amblypterus olfersi). t. IV, p. 293. These are listed, but not described, as from the “Craie du Bresil.” Cladocyclus gardneri Ag., noted, not described, from Brazil. V, p. 103. Calamopleurus cylindricus, from ‘‘Craie du Bresil.” t. V, p. 122, not described. Appendice, p. 1384, he mentions Gardner’s specimens from the north of Brazil. 4 BRAN NER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL AGASSIZ, LOUIS: On the fossil fishes found by Mr. Gardner in the Province of Ceara, in the north of Brazil. Hdinburgh New Philosophical Journal. XXX, 82-84. 8°. Edinburgh, 1841. AGASSIZ, LOUIS: Sur quelques poissons fossiles du Brésil (Lettre 4 M. Elie de Beaumont). Comptes Rendus de lV Académie des Sciences. XVIII, 1007- 1015. Paris, 1844. AGASSIZ, LOUIS: On the drift in Brazil, and on decomposed rocks under the drift. (Communicated by Alex. Agassiz.) American Journal of Science, 2d series, XL, 389-390. (XC.) New Haven, 1865. AGASSIZ, L.: Conversacoes scientificas sobre 0 Amazonas feitas na sala do externato do collegio de Pedro II. durante 0 mez de Maio de 1866. 8°, 71 pp. Rio de Janeiro, 1866. (Collected by F. Vogeli and translated from French to Portuguese by Ant. José Fernandes dos Reis. I. Formacao da bacia do Amazonas, 7 de Maio. Ii. Regimen dos aguas do Amazonas, 14 ’ de Maio. III. Phenomenos erraticos, 20 de Maio. IV. Vegetacio—Indios, 26 de Maio. V. As faunas, etc., 30 de Maio.) AGASSIZ, L.: Lettre 4 M. Marcou sur la Géologie de la vallée de.l’Amazone, avec des remarques de M. Jules Marcou. Bulletin de la Société Géologique de France, 2me sér. XXIV, 109-111. Paris, 1866. Same in German in Neues Jahrbuch fir Mineralogie fiir 1867. 180-181. Stuttgart. AGASSIZ, LOUIS: Physical History of the Amazon Valley. Atlantic Monthly, 49-60; 159-169. Boston, July and August, 1866. This article forms a chapter of “Geological Sketches,” which see. AGASSIZ, L.: Agassiz und seine Begleiter am Amazonas. Das Ausland, XXXIX. No. 19. 489-448. Augsburg, 8 Mai, 1866. (Aus dem Atlantic Monthly.) AGASSIZ, L.: Agassiz fahrt auf dem Amazonas von Monte Alegre nach der Serra von Erreré. Das Ausland, XXXIX, No. 48, 1129-1131. Augsburg, November 27, 1866. (Auf dem Atlantic Monthly.) AGASSIZ, L.: Report . . . on coal from Candiota. (Letter dated Rio de Janeiro, June 18, 1866, addressed to N. Plant.) It forms part of the report of Pakenham and Plant, pp. 23, q. v. London, 1867. AGASSIZ, LOUIS: Quelques détails sur un voyage sur VAmazone. Bulletin de la Société Géologique de France, 2me série, 1866-1867. XXIV,. 49-50. Paris, 1867. ee AGASSIZ, LOUIS: Geology of the valley of the Amazon. Abstract of lectures before the Lowell Institute, October and November, 1866. Annual of Scientific Discovery . . . for 1866 and 1867, 270-273. 8°. - Boston, 1867. AGASSIZ, L.: Observations géologiques faites dans la Vallée de l’Amazoiie. (Extrait d’une Lettre a M. Elie de Beaumont.) Comptes Rendus de VvAcadémie des Sciences, LXIV, 1269-1270. Paris, 1867. AGASSIZ, L.: Drift in Brazil. Annual of Scientific Discovery for 1866-1867, pp. 269-270. 8°. Boston, 1867. AGASSIZ, LOUIS: Geography of Brazil: the river Amazon. (Notes based on his Lowell lectures given in Boston, Oct., 1866.) Annual of Scientific Discovery or Year Book of Facts in Science and Art for 1866 and 1867, 357-358. 8°. Boston, 1867. AGASSIZ, L., and COUTINHO, Major JOAO MARTINS DA SILVA: Sur la Géologie de ?PAmazone. Bull. Soc. Géologique de France, 2me série, XXV, 685-691. Paris, 1868. Separate. 8°. Paris, 1867. AGASSIZ, L.: Bassin de L’Amazone. (Extrait du Voyage de M. le professeur Agassiz.) Bulletin de la Société de Géographie de Genéve, VII, 159-196. 8°. Généve, 1868. AGASSIZ, Professor and Mrs. LOUIS: A Journey in Brazil. XIX + 540 pages, ill. Boston, Ticknor & Fields, 1868 (chap. XIII, Physical History of the Amazons, 397-441, and many geological notes.) Review: Quar. Jour. of Science, V, 488-490. London, Oct., 1868. Review: Geol. Maga- zine, V, 456-459. London, 1868. AGASSIZ——-ALLEN 5 AGASSIZ, Madame et M. LOUIS: Voyage au Brésil. Traduit de l’anglais par Felix Vogeli. Ouvrage illustré de 54 gravures et contenant 5 cartes. 8°, 532 pp. Paris, 1869. AGASSIZ, L.: (Upon the geology of the Amazons, quoted from his Journey in Brazil.) Annual of Scientific Discovery for 1871, 243-245. Boston, 1871. AGASSIZ, LOUIS: On Hartt’s Geology and Physical Geography of Brazil. Neues Jahrbuch fiir Mineralogie, Geologie und Palwontologie, 1871, 62-63. Stuttgart, 1871. AGASSIZ, LOUIS.: South American expedition. Nature, VI, 216, 229-231, and 270-273. London, May, 1872. (Bears indirectly upon the glaciation of Brazil. Reprinted from the New York Tribune of June 26, 1872.) AGASSIZ, LOUIS: An abstract of a letter concerning glaciation in South America. American Journal of Science. (8rd ser., IV.) CIV, 135-1386. New Haven, 1872. AGASSIZ, L.: South American observations. (Concerning glaciation, etc.) Popular Science Monthly, I, 505. New York, August, 1872. AGASSIZ, Madame et M. LOUIS: Voyage au Brésil, abrégé sur la traduction de F. Vogeli par J. Belin de Launay et contenant une carte et 16 gravures. Deuziéme edition, 12°. XXIV + 268 pages. Paris, 1874. AGASSIZ, LOUIS: Geological sketches; physical history of the valley of the Amazon. Boston, 1886. Second series, pp. 153-229. (Published originally in Atlantic Monthly, July and August, 1866, q. v.) Review of Agassiz’s Geological sketches, Boston, 1876, in American Journal of Science, 3d series, XI, 232, New Haven, 1876. AGASSIZ, ELIZABETH CARY: Louis Agassiz, his life and correspondence. Edited by Elizabeth Cary Agassiz. 2 vols., XIV + 794 pages. 8°. Boston, 1882. Chap. XXI, 624-646, contains references to the geology of Brazil. Review: American Journal of Science, CXXX, 406. New Haven, 1885. Abstracts, ete., Das Ausland, XLII, 853-857; 877-880. Augsburg, 1869. AGUIAR, Col. F. M. DE SOUZA: Brazil at the Louisiana Purchase Exposi- tion, St. Louis, 1904. (Illustrated circular, with geologic and mining data and cuts, 160 pp.) ALBUQUERQUE, LIMA: See Lima. ALBUQUERQUE, LOURENCO CAVALCANTE DE: Officio dirigido a S. Ex. o Sr. Conselheiro Baraio do Penedo, a respeito do guano na ilha Rata, Fernando de Noronha. Awuzsiliador da Industria Nacional, No. 2, Li, 40-41. Rio de Janeiro, Fev., 1883. ALCANTARA, PEDRO DE: Documentos relativos ao tremor de terra havido em Pernambuco em 1811, offerecidos ao Instituto Historico e Geographico Brasileiro por Sua Magestade 0 Imperador. Revista do Inst. Hist., XXIII, 401-406. Rio de Janeiro, 1860. ALCANTARA, DOM PEDRO D’: Tremblement de terre survenu au Brésil le 9 Mai, 1886. Extrait d’une lettre de S. M. & M. Daubrée. Comptes Rendus de ’Academie des Sciences, CII, 1851-1352. Paris, 1886. Abstract: Revue Scientifique, 2me sér., 4me année. XIV, 764. Paris, 1874. ALCANTARA, DOM PEDRO D’: On the earthquake which occurred in Brazil May 9, 1886. Letter to the French Academy of Sciences. Nature, XXXIV, 187-188. London, 1886. ALENCAR, ARARIPE: v. ARARIPE, T. DE A. ALINCOURT, LUIZ D’: Resultado dos trabalhos e indagacées estatisticas da Provincia de Matto Grosso por Luiz d’Alincourt, sargento-m6r Engen- heiro. (Cuyaba, 1828.) Annaes da Bibliotheca Nacional do Rio de Janeiro, 1877-1878, III, fasciculo No. 1, pp. 68-161; fasciculo 2, pp. 225-278. Rio de Janeiro, 1877. Minas e geologia, 268-278. ALLEN, J. A.: Notes on the geological character of the country between Chique-Chique, on the Rio de Sao Francisco and Bahia, Brazil. Hartt’s Geology and Physical Geography of Brazil, 309-318. Boston, 1870. 6 BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL ALLPORT, S.: On the discovery of some fossil remains near Bahia in South America (with notes on the fossils by John Morris and T. Rupert Jones). Quarterly Journal Geol. Soc., XVI, 263-266. Figures and 4 plates. Lon- don, Dec., 1859. Abstract: Neues Jahrbuch fiir Mineralogie, 1860, 494. ALMEIDA, FRANCISCO ANTONIO: Manoel Timotheo da Costa. As Montan da Juréa (S. Paulo) O Novo Mundo, VII, 127, from the Commercio de Iguape, Provincia de S. Paulo. New York, Junho, 1877 ALMEIDA, FRANCISCO ANTONIO DE: Noticia sobre as minas de ferro de Jacupiranguinha. Bases de um projecto de exploragao. Memoria apresen- tada a sua exa. o Sir. Visconde do Rio Branco, 4°, 40 pp. Rio de Janeiro, 1878. ALMEIDA, GONCALVES DE: Annonce qu’un gisement d’ossements fossiles vient d’étre decouvert au Brésil, dans la province de Rio Grande do Sul. Comptes Rendus de V Acadenvie Sciences, CXIV, 378. Paris, 1892. ALMEIDA, Presidente LUIZ A. FERREIRA DE E OUTROS: Minas de carvao de pedra do Arroio dos Ratos. Revista de Engenharia, VI, 186. Rio de Janeiro, 28 de Agosto, 1884. ALMEIDA, G. OSORIO DE: Communicagiao feita sobre a applicacio do carvao nacional 4 traccio em estradas de ferro. Annuario do Estado do Rio Grande do Sul para o anno de 1906, pp. 256-263. Porto Alegre, 1905. ALMEIDA, G. OZORIO DE: v. GUIGNET, E. ALTON, E. D’: Uber die von dem verstorbenen Herrn Sellow aus der Banda Oriental mitgebrachten fossilen Panzerfragmente und die dazu gehorigen Knochen-tiberreste. Abhandlungen der Konig. Akad. der Wissenschaften cu Berlin. Aus dem Jahre 1833, 369-418. Plates, 4°. Berlin, 1835. ALVARO, SILVEIRA: v. SILVEIRA, ALVARO. ALVES, HERMILLO CANDIDO DA COSTA: Estrada de ferro da Victoria para Minas. Relatorio apresentado ao IlJm. e Exm. Sr. Conselheiro Thomaz José Coelho de Almeida, ete., pelo engenheiro Hermillo Candido da Costa Alves, Chéfe da commissao de estudos. 8°. Rio de Janeiro, Typographia Nacional, 1876. Aspecto, geologia e riquezas naturaes, 19-22: peat, chalk, iron in the province, granites, schists, plains of sedimentary rocks. AMAR, RAPHAEL DE: (Notes upon the richness of gold veins, Minas Ger aes.) . Neues Jahrbuch fiir Mineralogie, 1833, p. 547. Stuttgart, 1833. AMAZONAS, LOURENCO DA SILVA ARAUJO E: Diccionario topographico, historico, descriptivo da Comarca do Alto Amazonas. 12°. Recife, 1852. Orographia, 15-16; mineraes, 17-18. AMBAUER, HENRIQUE SCHUTEL: A provincia do Rio Grande do Sul, descripcaio e viagens. Revista do Instituto Historico, LI, pt. Il, 25-72. Rio de Janeiro, 1888. AMEGHINO, F.: La antiguedad del hombre en el Plata. II. El hombre en la formacion pampeana. (Brazil, 373, 391.) Buenos Aires, 1881. AMEGHINO, F.: See Gervais, Henri. AMEGHINO, F.: Las antiguas conexiones del continente Sud-Americano y la fauna eocena Argentina. Revista Argentina de Historia Natural. I, 123- 125. Buenos Aires, 1891. AMEGHINO, F.: Determinacion de algunos jalones para la restauracion de las antiguas conexiones del continente Sud-Americano. Revista Argentina de Historia Natural. I, 282-288. Buenos Aires, 1891. AMERICO, DOS SANTOS: v. SANTOS. AMMON, LUDW. VON: Devonische Versteinerungen von Lagoinha in Mato. Grosso (Brasilien). Zeitschrift der Gesellschaft fiir Erdkunde zu Berlin, XXVIII, 352-366. Berlin, 1893. (Appendix to paper of Dr. Vogel, q. v.) Abstract : Neues Jahrbuch fir Mineralogie, 1895, Il, 454. ANDERSON, JAMES E.: Report of the U. S. Consul in Rio de Janeiro, 1906. (Cf. Brandenburg, A. Bogus mines, ete.) ~ ( ANDRADA ANONYMOUS ANDRADA, D’: An account of the diamonds of Brazil. Nicholson’s Journal of Natural Philosophy, Chemistry and the Arts. I, 24-26. London, April, OT ANDRADA, MARTIM FRANCISCO RIBEIRO DE: Diario de uma viagem mineralogica pela provincia de S. Paulo no anno de 1805. Revista do Instituto Historico do Brazil. IX, 527-548, 2a edicao. Rio de Janeiro, 1869 (for 1847). Also in Diccionario geographico das minas do Brazil por F. I. Ferreira, 364-377. Rio de Janeiro, 1885. ANDRADA, MARTIM FRANCISCO RIBEIRO DE: Jornaes das viagens, pela Capitania de Sao Paulo, de Martim Francisco de Andrada, estipendiado como inspector das minas e matas, e naturalista da mesma capitania, em 1803 e 1804. Revista do Instituto Historico, XLV, Parte I, 5-47. Rio de Janeiro, 1882. (Many geological notes.) ANDRADA e SILVA, JOSE BONIFACIO DE, e ANDRADA, MARTIM FRAN- CISCO RIBEIRO DE: Voyage minéralogique dans les provinces de Saint Paul au Brésil. Article communiqué par M. Menezes Drummond, de Rio de Janeiro. Journal des Voyages, découvertes et navigations modernes, ou Archives géographiques du, 19me siécle, etc. XXXVI, 69-80; 216-227. Paris, 1827. Foot-note on pp. 69-70: “J’ai parlé dans un de mes précédens articles, cahier du mois de Juin, d’une voyage minéralogique entreprise in 1820 dans la province de Saint Paul au Brésil par mon ami le savant José Bonifacio d’Andrada, ex-ministre de lempereur Don Pedro, et par son respectable frére. La _ bienveillance dont ces illustres compatriotes m’honorent m’ayant valu la communication des notes recueillies dans cette excursion scientifique. J’ai cru devoir les rédiger en corps d’articles espérant que nos lectures me sSauraient gré de mon travail. M. de D.” At p. 227 the article is signed Menezes de Drummond. The same article is published in Bulletin des Sciences Naturelles et de Géologie, XVI, 411-415. Se.) Laris,. 1829: ANDRADA e SILVA, JOSE BONIFACIO DE, e MARTIM FRANCISCO DE ANDRADA: Viagem mineralogica na Provincia de Sao Paulo. Traduzida em francez pelo Conselheiro Antonio de Menezes Drummond e publicada no Journal des Voyages, XXXVI, 69-80; 216-227. Paris, 1827. Reprinted in Manual de Geologia. Por Nereo Boubée, Rio de Janeiro, 1846, annexo pp. 1-34, and in Diccionario geographico das minas do Brazil por F. I. Ferreira, pp. 341-364. Rio de Janeiro, 1885. ANKER: [Minerals (Peliom) collected by Pohl.] Taschenbuch fiir die - gesammte Mineralogie von Leonhard. l17ter Jahrgr. 703-707. Frankfurt a. M. 1823. ANONYMOUS: Genuine account of the present state of the diamond trade in the dominions of Portugal. By a Lisbon merchant. London, 1785. ANONYMOUS: Letter from Vienna signed * * * in regard to mineralogical work of Dr. Pohl in Minas Geraes and Goyaz and of Herrn Natterer and Varnhagen in Sao Paulo. MJMéineralogisches Taschenbuch fiir das Jahr, leon VOM Ko Cs Rk. von Leonhard, 1, Pt. L, 229-232. 8°. Krankfurt am Main, 1823. ANONYMOUS: Matrix of the Brazilian diamond. LHdinburgh Philosophical Journal, IX, 202. HEdinburgh, 1823. ANONYMOUS: 1825. See Modern Traveller. ANONYMOUS: An account of the mines and the Province of Minas Geraes in the Empire of Brazil, including a view of the manner of mining metals and precious stones. By a mining proprietor. The Monthly Magazine, or British Register, London (new series, I), March, 1826. 258-267; April, 1826. 395-404. London, 1826. The original article appears to have been written in Portuguese. Abstract under the title: Notice sur les mines de la province de Minas Geraes dans l’empire du Brésil . . . par un proprié- taire. Bulletin des Sciences Naturelles et de Géologie, XII, 374-375. Paris, 1827. Another abstract of the same, XVII, 214-218. Paris, 1829. 8 BRANNER—BIBLIGRAPHY OF THE GEOLOGY OF BRAZIL ANONYMOUS: Description de la province de Rio-Janeiro. Nouvelles Annales des Voyages, XULVII, 195-244; 2e article, XLVIII, 30-69; 3e article, XLVIII, 175-216. Paris, 1830. ANONYMOUS: L’art de Vérifier les dates depuis l’année 1770 jusqu’ 4 nos jours. XIII. 8°. Paris, 1832. (Brésil, 1-462. Fossils prés de la ville de Rio das Contas, 77-78, quoted from Cazal I, 78.) ANONYMOUS: Three years in the Pacific, including notices of Brazil, Chile, Bolivia, and Peru. By an officer of the United States Navy. (W. S. W. Ruschenberger?) Philadelphia, 1834. Chap. VIII, 65-71, on the geog- raphy, products, and diamond mines of Brazil. ANONYMOUS: Diamond districts of Brazil. Westminster Review, Oct., 1834. XXI, 297-319. See St. Hilaire. ANONYMOUS: The gold mines of Brazil. Penny Magazine, No. 553. IX, 441-443. London, Noy. 14, 1840. ANONYMOUS: Urspriinglich Lagerstitte der Diamanten. Pogg. Annalen der Phys. u. Chemie, LVIII, 474. Leipzig, 1843. ANONYMOUS: Indice da legislacio Portugueza sobre as Minas do Brasil. 2° Appendix, pp. 1-18 de Geologia Elementar applicada 4 Agricultura e Industria, etc. Por Nereo Boubée. Rio de Janeiro, 1846. The laws are cited down to the year 1816. ANONYMOUS: Sur lexploitation du diamant dans la province de Bahia (Brasil). Annales des Mines, 1852, II, 594. ANONYMOUS: Découverte de nouvelles mines d’or au Brésil, prés de Saint- Louis de Maranham. Nouvelles Annales des Voyages, 6me sér. II, 112-114. Paris, 1855. ANONYMOUS: Neue Gold-Linder. (Maranhio.) Petermann’s Mittheilun- gen, 1855. 119-120. Gotha, 1855. ANONYMOUS: Die Didimantwischerei in Brasilien u. die Diamantschneidereli in Amsterdam. Das Ausland, No. 51, 1856. ANONYMOUS: The reefs of Pernambuco. The Nautical Magazine and Naval Chronicle, 345-349. London, July, 1861. Quoted from the Moniteur de la Flotte. ANONYMOUS: Brazil: (Notes on mines). The Mining and Smelting Maga- zine, V, 44-45. London, Jan., 1864. ANONYMOUS: (Agassiz und die erratischen Bl6cke in der brasilianischen Provinz Cearé). Globus, IX, 382. Hildburghausen, 1865. ANONYMOUS: Descobrimento de Minas Geraes. Revista do Instituto His- torico, XXIX, Parte I, 5-114. Natureza mineral, 5-22. Rio de Janeiro, 1866. ANONYMOUS: The Roccas. Mercantile Marine Magazine, XIII, 35-50; 65-80; 141-143. London, 1866. ANONYMOUS: Der Pico do Itatiaiossu in Brasilien, eine Aufgabe fiir Berg- besteiger. Petermann’s Mittheilungen, XVII, 392. Gotha, 1871. ANONYMOUS: Exploration of Professor Hartt in Brazil. Annual Record of Science and Industry for 1872. Edited by Spencer F. Baird. 157-158. 8°. New York, 1873. ANONYMOUS: Commissdio Geologica. Diario do Rio, Rio de Janeiro, 7 de Julho de 1877. ANONYMOUS: A Commissaio Geologica do Brazil. Published in “O Vulgari- sador,” a newspaper in Rio de Janeiro, Brazil, Nov. 3, 1877. Reprinted in O Novo Mundo, an illustrated periodical published in New York. Janu- ary, 1878, VIII, 18-19. ANONYMOUS: Rochas calcareas no valle do Parahyba. Extrahido do Jornal do Commercio de 9 de Novembro de 1880. Revista de Engenharia, 1880, II, 206. Rio de Janeiro, 1880. ANONYMOUS: Os sambaquis (kjokken-moddings) de Santos. Boletim da Socicedade de Geographia de Lisbéa. 2a serie, No. 1, 118-119. Lisboa, 1880. ANONYMOUS 8) ANONYMOUS: Catalogo da Exposicio de Historia do Brazil realizada pela Bibliotheca Nacional de Rio de Janeiro a 2 de Dezembro de 1881. 2 vols. 8°. Rio de Janeiro, Typ. G. Leuzinger & Filhos, 1881. Vol. II, Classe X. Historia natural, obras geraes, pp. 993-997; mineralogia e geologia, 1044- OHON is ANONYMOUS: Estatistica da produccio do ouro na provincia de Minas Geraes no anno de 1879. Annaes da Escola de Minas de Owro Preto, No. 1, 151-154. Rio de Janeiro, 1881. ANONYMOUS: Estado actual da extraccio do ouro no municipio de Ouro Preto, comparado ao do anno de 1814. (Noticia.) Annaes da Escola de Minas de Ouro Preto, No. 1, 155-168. Rio de Janeiro, 1881. ANONYMOUS: Diversos horizontes auriferos da provincia de Minas Geraes. Auaxiliador da Industria Nacional, Julho 1881, XLIX, 154-158. ANONYMOUS: Fabrica de ferro de Ypanema. Auwsxiliador da Industria Nacional, XLIX, 158-159. Rio de Janeiro, Julho 1881. Quoted from the Gazeta de Noticias. ANONYMOUS: The present state of science in Brazil. Science, I, 211-214. Cambridge, March 30, 1883. ANONYMOUS: Brazilian minerals. S. Paulo. (Iron, oil, coal.) Zhe Mining Journal, LIII, 317. London, July 14, 1883. ANONYMOUS: Collecc6es paleontologicas. Revista de Engenharia, 28 de Out. de 1883, V, 289. Extrahido do Jornal do Commercio de 12 de Out. de 1883. Rio de Janeiro, 1883. ANONYMOUS: Collecc6es palentologicas da extincta Commissao Geologica. Do Jornal do Commercio de Rio de Janeiro. Revista de Engenharia, V, . 267-268. Rio de Janeiro, Out. 14, 1883. ANONYMOUS: The Ouro Preto gold mines of Brazil (Limited), [visit of M. Belloc]. The Mining Journal, LVI, 1059. London, Sept. 11, 1886. ANONYMOUS: Ouro Preto gold mines of Brazil (Limited). (From the Paris Bourse.) The Mining Journal, LVII, 768. London, June 18, 1887. ANONYMOUS: Forest and mineral wealth of Brazil. Journal of the Society of Arts, XX XIX, 933-934. London, 1891. ANONYMOUS (?): Relatorio da Companhia Aurifera de Minas Geraes. Rio de Janeiro, 1 de Julho, 1893. ANONYMOUS: Brazilian exploration in the Amazon valley. Geographical Journal, I, n. 4, 346-347. London, 1893. ANONYMOUS: Manganese mining in Brazil. Journal of the Society of Arts, XLVIII, 56. London, Dec. 1, 1899. , ANONYMOUS: Carbons in Brazil. Journal of the Society of Arts, XLVII, 662-663. London, 1899. ANONYMOUS: Manganerzgewinnung in Brasilien. (Auszug aus.) Stahl und Hisen, n. 1, 1899, s. 48. Zeitschrift fiir praktische Geologie, April, 1899, p. 146. ANONYMOUS: Mining in Brazil. Mining Journal, LXX, 1466. London, Dee. 1, 1900. ANONYMOUS: Mica deposits in Sao Paulo. Annual report of the director of the Bureau of the American Republics for the year 1900. Pt. II, 220. Washington, 1900. ANONYMOUS: (New monazite deposits in Bahia.) Annual report of the director of the Bureau of the American Republics for the year 1899. Pt. III, 608. Washington, 1900. ANONYMOUS: The mining industry (of Brazil). Monthly Bulletin of the Bureau of American Republics, IX, 284-286. Washington, 1900. ANONYMOUS: Mining conditions and mineral resources in Brazil. Hngineer- ing and Mining Journal, LXXII, 427-429, 3 ills. 4°. New York, Oct. 5, 1901. Also in Brazilian Mining Review, I, 17-19. Ouro Preto, 1902. 10 BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL ANONYMOUS: The Morro Velho gold mine, Brazil. Engineering and Mining Journal, UXXII, 485-489, ill. New York, Oct. 19, 1901. Also in Brazilian Mining Review, I, 6-11. Ouro Preto, July, 1902. ANONYMOUS: A mineracio Rio Grandense. Catalogo da Exposicao estadual do Rio Grande de Sul em 1901. 9-23. 4°. Porto Alegre, 1901. ANONYMOUS: A large manganese discovery in Brazil. The Mining Journal, LXXI, 161. London, Feb., 1901. Abstract: Journal of the Iron and Steel Institute, LIX, 345. London, 1901. ANONYMOUS: Brazil. GARDNER, GEORGE: Travels in the interior of Brazil, principally through the northern provinces and the gold and diamond districts during the vears 1836-1841. 8°, XVI +562 pp., map. London, 1846. Second ed., XVIII + 428 pp... map and plate. 8°. London, 1849. Many notes on the geology especially of the interior of Ceara, Piauhy, and Minas Geraes. GARDNER, GEORGE: Reisen in innern Braziliens, besonders dureh die nord- lichen Provinzen und die Gold- und Diamanten-districte. Aus dem Engl. von M. B. Lindau, 2 vols., 1 map. 8°. Dresden u. Leipzig, 1848. Ger- man translation of the title above. GAUDICHAUD, C.: Voyage autour du monde, entrepris par ordre du Roi... executée sur les corvettes de S. M. l’Uranie et la Physicienne pendant les année 1817-1820, par M. Louis de Freycinet. 9 vols. Botanique par M. Charles Gaudichaud. 4°, vol. I, Géologie du Rio de Janeiro, 9-10. Paris, 1826. GAUTIER, FERDINAND: Ipanema et Taubaté. Revista Industrial de Minas Geraes. Anno 1, No. 8, 193-194. Ouro Preto, 15 Maio, 1894. GEHLEN, A. F.: Platinum und Palladium in Brazilien und St. Domingos gefunden. Schweigger’s Journal fiir Chemie und Physik, I, 362. Nurem- burg, 1811. GEIKIE, JAMES: The evolution of climate. The Scottish Geographical Maga- cine, VI, 57-78, and map showing the geological and geographical develop- ment of Brazil. Edinburgh, 1890. GHIKIE, JAMES: Address to the geographical section of the British Associa- tion for the Advancement of Science, Edinburgh, 1892. The Scottish Geo- graphical Magazine, VIII. Edinburgh, 1892. (Geology of east coast of Brazil, 471.) GEINITZ, H. B.: Ueber einige Eruptivgesteine in der Provinz Sio Paulo in Brasilien. Abh. Naturwis. G. Isis, Abtheilung 6, 31-34. Dresden, 1890. GHINITZ, H. B.: Sur Stereosternum twnidum, Cope, du Musée Royal de Minéralogie de Dresde provenant de Sao Paulo (Brésil). Traduit sur le manuscrit allemand par J. Fraipont. Annales de la Société Géologique de Belgique, 4°, XXV bis, ler livraison, 35-42, Liége, 7 Sept., 1900. GENTH—-GIRARD DS GENTH, F. A.: Contributions to mineralogy. Joséite and Tetradymite. Pro- ceedings American Philosophical Society, XXIII, 31-34. Philadelphia, 1886. Abstract: Zeitschrift fur Krystallographie und Mineralogie (Groth), XII, 487-488. Leipzig, 1887. GERBER, H.: See BURTON, R. F. GERBER, HENRIQUE: Geographical notes on the province of Minas Geraes. (Translated and communicated by Capt. R. F. Burton.) Jowr. Royal Geog. Soc., XLIV, 262-300. London, 1874. Abstract: The Geol. Record for VSsi5, IZ. Bondons 1877. GERBER, HENRIQUE: Nocoes geographicas e administrativas da Provincia de Minas Geraes por Henrique Gerber, engenheiro da mesma Provincia. Re-impressio da la edicao de 1863. Hannover, 1874. Geologia, 17-20; mineracao, 31-34. GERVAIS, HENRI, et AMEGHINO, FLORENTINO: Les mammiféres fossiles de ’Amérique du Sud. 8°, XI + 225 pp. Paris and Buenos Aires, 1880. GERVAIS, PAUL: Recherches sur les mammiféres fossiles de lAmérique Meridionale. [Mémoire accompagné de dix planches _ lithographiées. Extrait de la Zoologie de ’ Expédition dans les parties centrales de l’Amér- ique du Sud publiée sous la direction de M. le Comte Francis de Castel- nau.] Paris, 1855. 4°, 63 pp. and plates. Some Brazilian tossil mam- mals. GERVAIS, M. PAUL: Mémoir sur plusieurs espéces de mammiféres fossiles propres 4 ’?Amérique Méridionale. JM/émoires de la Société Géologique de Prance, 2e sér:, 1X. 5e, 1-44, et planches. 4°. Paris, 1873. Brazilian fossil mammals, 21, 23, 26. GERVAIS, P.: On the fossil mammalia of South America. Annals and Maga- zine of Natural History, 5th series, II, 271-272. Loudon, 1878. GERVAIS, P.: (Sur une vertébre fossile de la région de Bas-Amazone. ) Comptes Rendus de V Acad. Sci., LX XXIII, 29. Paris, 1876. Journal de Zoologie, V, 232-236, plate. Paris, 1876. GERVAIS, PAUL: Crocodile gigantesque fossile au Brésil. (Dinosuchus terror.) Journal de Zoologie, V, 232-236 + 1 planche. Paris (1876). GERVAIS, P.: Tortue gigantesque fossile au Brésil. Journal de Zoologie, VI, 283-285 and plate. Paris, 1877. Abstract:Geological Record for 1877, 287. London, 1880. (This is Zestudo elata, from the Pleistocene of the lower Aimmazonas, two thirds the size of the giant turtle of India, Colloso- chelys Atlas.) GERVAIS, P.: Nouvelles recherches sur les mammiféres fossiles propres 4 YAmérique Méridionale. Comptes Rendus de VAcad. Sci., LXXXVI, 1359- 1362. Paris, 1878. Abstract: The Geological Record for 1878, 297. Ton- don, 1882. GIBSON, A. M.: The mineral resources of Brazil. Hngineering and Mining Journal, XLIX, 85-86. New York, 1890. GIBSON, A. M.: Brazil’s hidden wealth. Gems, gold, rubber and coffee. New York Times, Jan. 26, 1890. GILL, A. C.: Petrographical notes on a rock collection from Fernando de Noronha. (A preliminary notice.) Johns Hopkins University Circulars, VII, No. 65, 71-72. Baltimore, April, 1888. GILMAN, C. E.: v. BRANNER, J. C., and GILMAN, C. E. GINTY, W. G.: Report on the Candiota coal. (Part of the paper by Mr. Parkenham, 23-24, q. v.) London, 1867. GINTY, W. G.: Report on the Candiota coal. (Letter addressed to Nathaniel Plant.) Appendix H of “Brazil and the Brazilians.” By Rev. James C. Fletcher and Rev. D. P. Kidder. 9th ed., 637. London, 1879. GIRARD. H.: Der Diamant und seine Muttergestein in Brasilien. Neues Jahrbuch fur Mineralogie, etc. Von Dr. K. C. von Leonhard und Dr. H. G. Bonn, Jahrgang, 1848, 307-310. Stuttgart, 1843. 54 BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL GLOCKER, [E. F.]: Ueber brasilianische Diamanten. EHrdman’s Journal fir Praktische Chemie, XX XVIII, 318-320. Leipzig, 1846. GOELDI, EMIL A.: See Derby, O. A. “Physical geography and geology of Brazil.” GOLDI, EMIL A.: Eine Naturforscher-Fahrt nach dem Litoral des stidlichen Guyana zwischen Oyapock und Amazonenstrom. (October bis November, 1895.) Separatabdruck aus dem Jahresbericht der St. Gallischen Natur- wissenschaftlichen Gesellschaft, 1896-97. St. Gallen, 1896. (Geology, 37, 40, 45, chart.) GOMES, ALFFONSO H. DE SOUZA: Relatorio sobre 0 melhoramento do porto do Natal, apresentado ao Ministro e Secretario dos Negocios da Agricul- tura. Natal, 1890. Pp. 10, map of the reef. Notes on the geology of the stone reef and harbor of Natal, Rio Grande do Norte. GOMES, CARLOS THOMAZ DE MAGALHAES: Analyse do lignito de Taqua- rasst. Revista Industriul de Minas Geraes. Anno 1, No. 1, 20. Ouro Preto, 15 de Outubro, 1893. GOMES, CARLOS THOMAZ DE MAGALHAES, e SILVA, AUGUSTO BAR- BOSA DA: As clivagens do quartzo. Revistu Industrial de Minas Geraes. Anno IV, No. 22, 273-274. Ouro Preto, 30 de Marco, 1897. Annaes da Escola de Minas, no. 5, 19-24. Ouro Preto, 1902. GOMES, CARLOS THOMAZ DE MAGALHAES: (Analyses de 15 caleareos do Brazil.) Annaes da Escola de Minas, no. 5, 171-182. Outro Preto, 1902. GOMES, CARLOS THOMAZ DE MAGALHAES: (Analyses de 20 amostras de manganez.) Annaes da Escola de Minas, no. 5, 185-192. Ouro Preto, 1902. GOMES, CARLOS THOMAZ DE MAGALHAES: (Diversos analyses de mineraes do Brazil.) Annaes da Escola de Minas, no. 5, 201-207. Ouro Preto, 1902. GOMES, HENRIQUE CARLOS DE MAGALHAOS: (HExploracio geologica a oeste da Mantiqueira), 18-29 of Annexo A. do relatorio apresentado ao Dr. Secretario de Estado da Agricultura do Estado de Minas Geraes pelo Inspector de Terras e Colonizacaio, Dr. Carlos Prates em 1897. Ouro Preto, 1897. GOMES, JOSE COELHO: Empire of Brazil. Commercial and emigrational guide to Brazil. Compiled and translated from official publications by José Coelho Gomes, acting secretary of the Brazilian Legation, Washing- ton, U. S. A. 8°. Washington, 1885. Mineral resources, 44-46. GONCALVES, ALPHEU DINIZ: O Hydrobucholzite (da Bahia). Boletim da Directoria da Agricultura, etc., do Estado da Bahia. VIII, 49-51. Bahia, 1906. GONNARD, FERDINAND: Sur quelques cristaux de quartz du Brésil. Buille- tin de la Société Francaise de Minéralogie, XXV, 56-59. Paris, 1902. Abstract: Zeitschrift fur Krystallographie und Mineralogie (Groth), XXXIX, 184-185. Leipzig, 1904. GONNARD, FERDINAND: Sur un cristal d’améthyste du Brésil. Bulletin de la Société Francaise de Minéralogie, XXV, 59-60. Paris, 1902. Abstract: Zeitschrift fur Krystallographie und Mineralogie (Groth), XXXIX, 184- 185. Leipzig, 1904. GONZAGA DE CAMPOS: v. CAMPOS, L. F. GONZAGA DE. GORCEHIX, HENRI: Notice sur le gisement et l’exploitation de lor a Lavras, province de Rio Grande du Sud. Bull. Soc. de VIndustrie Minérale. St. Etienne, 2me sér., IV, 361-381. Paris, 1875. Abstract: The Geological Record for 1875, 121. London, 1877. GORCHIX: Résultats d’une premiére exploration de la province de Rio Grande du Sud (Brésil). Bull. Soc. Géol. de France, 3me série, III, 55-56. Paris, 1875. Abstract: The Geological Record for 1875, 121. London, 1877. GORCHIX, HENRIQUE: Conferencias feitas no Museu Nacional. 4°, 31 pp. Rio de Janeiro, 1876. GORCEIX 55 GORCEIX, H.: Noticia sobre a jazida de cobre em Lavras e Cacapava na provincia de S. Pedro do Rio Grande do Sul. 8°, 8 pages. Rio de Janeiro, 1876. GORCEIX, H.: Sur la canga du Brésil et sur de bassin d’eau douce de Fonseca. Comptes Rendus de VAcad. Sci. LXXXII, 631-682. Paris, 1876. GORCHIX, H.: Les explorations de Vor dans la province de Minas Geraes, Brésil. Bull. Soc. Géogr., 6me série, XII, 530-5438. Paris, 1876. GORCEIX, H.: Sur une roche intercalée dans les gneiss de la Mantiqueire (Brésil). Comptes Rendus de VAcad. Sci. UXXXII, 688-689, 1876. Also Bull. Soc. Géol. de France, 3me série, LV, 434-435. Paris, 1876. GORCHIX, H.: Note sur la roche vulgairement au Brésil sous le nom de Canga, et sur le bassin d’eau douce de Fonseca (province de Minas Geraes). Bull. Soc. Géol. de France, 3me série, 1V, 321-323. Paris, 1876. GORCHIX: Sur divers mineraux du Brésil. (Hxtrait d’une lettre.) Bull. Soe. Géol. de France, 3me série, IV, 522. Paris, 1876. GORCHIX, H.: Mina de carviio de pedra em Minas Geraes. Officio dirigido ao Presidente da Provincia. Ausxiliador da Industria Nacional, No. 7, XLVI, 164-165. Rio de Janeiro, Julho, 1878. GORCEHIX, H.: Estudos geologicos e mineralogicos sobre algumas localidades da Provincia de Minas Geraes pelos alumnos engenheiros da Hscola de Minas de Ouro Preto. Archivos do Museu Nacional do Rio de Janeiro, III, 9-10. Rio de Janeiro, 1878. GORCEIX, HENRIQUE: Noticia sobre a jazida e exploracdao do ouro em Lavras e em Cacapava, Provincia de S. Pedro do Rio Grande do Sul. (Traduzida do Francez.) 8°, 28 pages. Rio de Janeiro, 1874. Tambem no Auxiliador da Industria Nacional. No. 5, Maio de 1878, XLVI, 109- 114; No. 6, Junho de 1878, 133-137. Rio de Janeiro, 1878. GORCEHIX, H.: (Gisements de topaze au Brésil.) Revue de Géologie pour les années 1876 et 1877, 199-200. Paris, 1879. GORCEIX: Sur le gisement du diamant au Brésil. (Hxtrait d’une lettre a M. Delesse.) Bull. Soc. Minéral. de France, III, 36-38. Paris, 1880. Ab- stract: Zeitschrift fur Krystallographie und Mineralogie (Groth), IV, 407. Leipzig, 1881. GORCHIX, HENRIQUE: O ferro e os mestres de forja na Provincia de Minas Geraes. 8°, 16 pages. Ouro Preto, 1880. Idem, 4°, 24 pp. Rio de Ja- neiro, 1880. GORCEHIX: Sur les schistes cristallins du Brésil et les terres rouges qui les recouvrent. Extrait de lettres 4 M. Delesse. Comptes Rendus de lV Acad. Sci., XCI, 1099-1101. Paris, 1880. GORCEIX, H.: Sur la martite du Brésil. (Hxtrait d’une lettre a M. Delesse.) Comptes Rendus de VAcademie des Sciences, XC, 316-318. Paris, 1880. Abstract: Neues Jahrbuch fiir Mineral., 1881, I, 18, Referate. Abstract: Zeitschrift fur Krystallographie und Mineralogie (Groth), IV, 408. Leip- zig, 1881. GORCEIX, HENRIQUE: The iron industry of Minas Geraes. Jhe Rio News, VII, No. 24, Aug. 24, 1880; VII, No. 25, Sept. 5, 1880. Rio de Janeiro, 1880. From Revista Brazileira, Rio de Janeiro. GORCEIX, HENRIQUE: Geology of the Province of Minas Geraes. Abstract of two articles in the Annaes da Hscola de Minas de Ouro Preto. The Rio News, VIII, No. 15, Rio de Janeiro, May 24, 1881. Abstract: Amer. Jour. Sci., CX XII, 221-225. New Haven, 1881. GORCEHIX, H.: Estudo chimico e geologico das rochas do centro da Provincia de Minas Geraes. Annaes da Escola de Minas de Ouro Preto, No. 1, 1-12. Ouro Preto, 1881. GORCHIX, H.: Estudo geologico das jazidas de topazios da provincia de Minas Geraes. Annaes da Escola de Minas de Ouro Preto, No. 1, 13-34. Ouro Preto, 1881. 56 BRANNER—-BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL GORCEIX: Sur les gisements diamantiféres de Minas Geraes, Brésil. Comptes Rendus de VAcad. des Sci., XCIII, 981-983. Paris, 1881. Bull. Soc. Min- éral. de France, V, 9-13. Paris, 1882. Abstract: Neues Jahrouch fur Mineralogie, 1883, I, 378-379, Referate. GORCEHIX, H.: Etude géologique des gisements de topazes de la province de Minas Geraes, Brésil. Annales Scientifiques de VEcole Normal Supérieure, 2e9ser, MI Slea2e2 maps: ©4225 Rarisglss2: GORCHIX, H.: Brazilian diamonds and their origin. Popular Science Monthly, XXI, 610-620. New York, 1882. GORCHIX, H.: Note sur un mica vert des quartzites d’Ouro Preto, Brésil. Bull. Soc. Minéral., V, 308-310. Paris, 1882. Abstract: Newes Jahrbuch fiir Mineralogie, 1884, 1, 20, Referate. Abstract: Zeitschrift fur Krystal- lographie und Mineralogie (Groth), IX, 593. Leipzig, 1884. GORCHIX, H.: Diamants et pierres précieuses du Brésil. La Revue Scien- tifique, 3me série, III, 2e année, ler, sér., Janvier 4 Juillet, 1882, 553-561. Paris, 1882. GORCHIX: Sur les gites diamantiféres du centre de la province de Minas Geraes (Brésil). Bull. Soc. Géol. de France, 3me série, X, 134-135. Paris, 1882. Abstract: Transactions of the North of England Institute of Mining and Mechanical Engineers, XXII, 29. Neweastle-upon-Tyne, 188+. GORCHIX, H.: HWstudo chimico e mineralogico das rochas dos arredores de Ouro Preto. Annaes da Escola de Minas de Ouro Preto, 1883, N. 2, 7-23. Revista de Engenharia, 14 de Noy. de 1883, V, 297-298 ; 28 de Nov. de 1883, V, 314-316; 14 de Dez. de 1883, V,. 325-328. Rio de Janeiro, 1883. GORCHEIX, H., et JANNETTAZ, ED.: Note sur quelques mineraux des roches metamorphiques des environs d’Ouro Preto. (Minas Geraes, Brésil), avec observations par Ed. Jannettaz. Bull. Soc. Minéral. de France, VI, 27-34. Paris, 1883. Abstract: Newes Jahrbuch fir Mineralogie, 1884, II, 302-303, Referate. Abstract: Zeitschrift fur Krystallographie und Mineralogie (Groth), X, 620-621. Leipzig, 1885. GORCEIX, H.: Note sur un oxyde de titane hydraté, avee acide phosphorique et diverses terres, provenant des graviers diamantiféres de Diamantina, Minas Geraes, Brésil. Bull. Soc. Minéral. de France, VII, 179-182. Paris, 1884: Abstract: Zeitschrift fir Krystallographie und Mineralogie (Groth), XI, 638. Leipzig, 1886. GORCEHIX, H.: Lund e suas obras no Brazil (segundo o professor Reinhardt). Annaes da Escola de Minas de Ouro Preto, No. 3, pp. T-58. Rio de Janeiro, 1884. GORCHIX, H.: Géologie (du Brésil). La Grande Encyclopédie, VII, 1081. 4°. Paris: 1m. ad GORCHIX, H.: Bacias tertiarias d’agua doce nos arredores de Ouro Preto (Gandarela e Fonseca), Minas Geraes, Brazil. Annaes da Escola de Minas de Ouro Preto, No. 3, 95-114. Rio de Janeiro, 1884. .GORCEHIX: Noticia sobre os cascalhos diamantiferos. Annaes da Hscola de Minas do Ouro Preto, No. 3, 195-207. Contendo os dois artigos seguintes: Noticia relativa a alguns mineraes dos cascalhos diamantiferos contendo- acido phosphorico, alumina e outras terras do familia do cerium, 197-202. Noticia relativa a um zZeolitho de uma rocha pyroxenica da bacia do Abaeté, Minas Geraes, 205-207. Rio de Janeiro, 1884. Abstract: Trans- actions of the North of England Institute of Mining and Mechanical Engi- neers, XXXIV, 38. Newcastle-upon-Tyne, 1885. GORCHIX, H.: Note sur une zéolite d’une roche pyroxenique du bassin de Abaété, Minas Geraes, Brésil. Bull. Soc. Minéral. de France, VII, 32-35. Paris, 1884. Annacs da Escola de Minas de Ouro Preto, n. 3, 1884, 205- 210. Abstract: Neues Jahrbuch fiir Mineralogie, 1886, I, 188-189, Referate. Abstract: Zeitschrift fiir Krystallographie und Mineralogie (Groth), XI, 203. Leipzig, 1886. GORCEIX 57 Or GORCHEIX, H.: Sur les minéraux qui accompagnent le diamant dans le nouveau gisement de Salobro, province de Bahia, Brésil. Comptes Rendus de VvAcad. Sci., XCVIII, 1446-1448. Paris, 1884. Abstract: Zeitschrift fiir Krystallographie und Mineralogie (Groth), XI, 639. Leipzig, 1886. GORCEIX: Nouveau mémoire sur le gisement du diamant 4a Grio Mogor, province de Minas Geraes, Brésil. Comptes Rendus de VAcad. Sci. XCVIII, 1010-1011. Paris, 1884. GORCHIX: Gisement de diamants de Grao Mogor, province de Minas Geraes, Brésil. Bull. Soc. Géol. de France, 3me série, XII, 538-545. Paris, 1884. Abstract: Transactions of the North of England Institute of Mlining and Mechanical Engineers, XXXIV, 45. Newcastle-upon-Tyne, 1885. GORCEIX, H.: Etude des minereaux qui accompagnent le diamant dans le gisement de Salobro, province de Bahia (Brésil). Bull. Soc. Minéral. de France, VII, 209-218. Paris, 1884. Estudo dos mineraes que acompanhio o diamante na jazida de Salobro provincia da Bahia, Brazil. Annaes da Escola de Minas de Ouro Preto, n. 3, 219-227. Rio de Janeiro, 1884. Ab- stract: Transactions of the North of England Institute of Mining and Mechanical Engineers, XXXIV, 38. Neweastle-upon-Tyne, 1885. GORCEIX, H.: Analyses feitas no laboratorio de docimasia da Escola de Minas de Ouro Preto, II. Ouro do Tapnia, Bahia, 201, V (Com Leonidas Da- mazio). Amostras de phosphatos, 203-207. Annaes da Escola de Minas de Ouro Preto, 1885, No. 4, 201-208. GORCHIX: Sur la flexibilité des roches du Brésil connues sous le nom @itacolu- mites. Bull. Soc. Géol. de France, 3me série, XIII, 272. Paris, 1885. GORCEIX, H.: Sur des sables 4 monazites de Caravellas, province de Bahia Brésil. Comptes Rendus de VAcad. Sci., C, 356-358. Paris, 1885. Also Bull. Soc. Minéral. de France, VIII, 32-35. Paris, 1885. GORCHIX, H.: Estudo sobre a monazita e a xenotima do Brazil. Annaes da Escola de Minas de Ouro Preto, N. 4, 29-48. Ouro Preto, 1885. Abstract: Bull. Soc. Francaise Minéral., X, 160-161. Paris, 1887. Abstract: Monthly Bulletin of American Republics, VI, 596. Washington, 1898. GORCEIX, H.: Sur le xenotime de Minas Geraes (Brésil). Comptes Rendus de V Acad. Sci., CII, 1024-1026. Paris, 1886. Abstract: Neues Jahrbuch fir Minéral., 1888, I, 8-9. Referate. GORCHIX, H.: Sur le gisement de diamants de Cocaés, province de Minas Geraes, Brésil. Comptes Rendus de l’Acad. Sci., CV, 1139-1141. Paris, 1887. Abstract: Newes Jahrb. f. Mineral., 1889, I, 119-120, Referate. GORCEIX, HENRI: Mineralogie (du Brésil), Chap. IV, 61-104 of le Brésil en 1889. Paris, 1889. See F. J. de Santa Anna Nery. GORCEIX, HENRI: La géologie (du Brésil). See “Le Brésil by HE. Levasseur, extrait de La Grande Encyclopédie, Chapitre IV, 7-8. 2e edition. Paris, 1889. See LEVASSEUR. GORCHIX, HENRI: Le Brésil en 1889 avec une carte de Empire en chromo- lithographie, des tableaux statistiques, des graphiques et des cartes. Ouvrage publié par les soins dusyndicat du comité franco-brésilien pour Yexposition universelle de Paris. Avec la collaboration de nombreux écrivains du Brésil sous la direction de M. F. J. de Santa Anna Nery. (Minéralogie, par Gorceix.) In 8°, XIX, 699 pages. For the part relating to coal in Brazil, abstract in The Iron and Coal Trades Review, XLII, 296. London, March 13, 1891. Also Journal of the Iron and Steel Instituute, I, 299. London, 1891. GORCEIX, H.: L’état de Sao Paulo, Brésil. Comptes Rendus Soc. Géogr., 1890, ' 499-505. Paris, 1890. GORCEIX, H.: (Exploracédes geographicas no Brazil.) Revista de Engenharia, No. 251, XIII, 360-362. Rio de Janeiro, 14 de Fevereiro de 1890. GORCHIX, H.: Etude de gisements de diamants dans l’Etat de Minas-Geraes (Brésil). Compte Rendu de VAssociation Frangaise pour VAvancement des Sciences, 19me session, ler partie, 186. Paris, 1890. 58 BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL GORCEIX, H.: (Letter regarding the explorations in Brazil, especially those of Derby, addressed to the Société Géographique.) Compte Rendu des Séances de la Société de Géographie, 1890, 499-506. Paris, 1890. GORCHIX, HENRI: Minas Geraes, l’un des Etats-Unis du Brésil; situation, resources, population. 30 pp. 8°. Paris, 1891. GRACA, JOAO CORDEIRO DA: Relatoria dos estudos mineralogicos e geo- logicos da Provincia de S. Pedro do Rio Grande do Sul apresentado ao Governo Imperial. 8°, 101 pp. Rio de Janeiro, 1883. GRACA, JOAO CORDEIRO DA: Breve noticia histcrica do desenvolvimento da siderurgia e estatistica de algumas fabricas da Europa; seu progresso nos Estados Unidos colligida e traduzida pelo Engenheiro Joao Cordeiro da Graca. Publicada por ordem do Exm. Sr. Conselheiro Henrique d’ Avila, Ministro e Secretario d’Estado dos Negocios da Agricultura, Commercio e Obras Publicas. Rio de Janeiro, 1883. 87-93, account of a visit to the Fabrica de Ferro de 8S. Joao de Ypanema. GRAEFF, F. FR.: Mineralogisch-petrographische Untersuchung von Elaolith- syeniten von der Serra de Tingué, Provinz Rio de Janeiro, Brasilien. Neues Jahrbuch fiir Mineralogie, 11, 222-262. Stuttgart, 1887. Separate, Stuttgart, 1887. Abstract in Mineralogical Mag. and Jour. Mineral. Soce., VII, No. 35, 231-237. London, 1887. Abstract: Zeitschrift fur Krystallo- graphie und Mineralogie (Groth), XV, 637-688. Leipzig, 1889. GRAEFF, FRANZ FR.: Laavenit in brasilianischen Elaeolithsyenit. Neuwes Jahrbuch fiir Mineralogie, 1887, I, 201-203. Briefliche Mittheilungen. Abstract: Bull. Soc. Francaise de Minéralogie, XI, 251. Paris, 1888. Abstract: Zeitschrift fur Krystallographies und Mineralogie (Groth), XIV, 498. Leipsig, 1888. GRAHAM, MARIA: Journal of a voyage to Brazil. By Maria Graham. Lon- don, 1824. (Note on fossil bones in the State of Pernambuco eight leagues northeast of Penedo and near Recife, 130.) GRANDIDIER, ALFRED: Les cartes et les appareils de géographie et de cos- mographie, les cartes géologiques et les ouvrages de metéoroligie et de statistique. Rapports du Jury International, Groupe II, Classe 16, Expo- sition Universelle Internationale de 1878 a Paris. 8°. Paris, 1882. Cartes géologiques du Brésil, 482-483. GRASHOF, HE. EH. F.: Landschaftsbilder an der Bay von Rio de Janeiro. Globus, X, 235. Braunschweig, 1866. GRATEAU, ED.: Découverte de la houille au Brésil. Annales du Génie Civil. (Année, 1864.) 8°, III, 510. Paris, Eugéne Lacroix, Editeur, 1865. GRAVATA, A.: Mineral resources of Bahia. Quoted from the Diario da Bahia, in Monthly Bulletin of the International Bureau of American Republics, XVI, 355-357. Washington, 1904. GRAVATA, A.: Memoria sobre as minas da Bahia. Boletim da Secretaria de Agricultura do Estado da Bahia. III, 157-166. Bahia, 1904. GREVEN, FR.: Manganerze in Brasilien. Stahl und Eisen, 1899, 19, 439. Chemisches Repertorium (Supplement zur Chemiker Zeitung, No. 42), XXIII, 160. Cothen, 27 Mai, 1899. Abstract: Jour. Iron and Steel Inst., LVI, 322-323. London, 1899. GRODDECK, Dr. VON: Ueber das Vorkommen von Gold- Kupfer- und Bleier- zen in der Provinz Rio Grande do Sul in Brasilien. Berg- wnd Hiitten. Zeitg., 7 December, 1877. No. 49, 422-424. Abstract: Neues Jahrbuch fiir Mineral., 1878, 419. Abstract: Zeitschrift fiir Krystallographie und Miner- alogie (Groth), III, 324-325. Leipzig, 1879. GROSSI, V.: Climatologia, geologia e idrologia medica dello Stato Brasiliano’ di Minas Geraes. Torino, 1893. GROSSI, V.: Le miniere del Brasile, Roma, 1895. Abstract: Scottish Geo- graphical Magazine, XII, 471-472. Edinburgh, 1896. GROSSI, DE VINCENZO: Nel paese delle Amazzoni. 12°, 130 pp. Roma, 1897. Geografia fisica, 9-32. GROSSI—H AIDINGER 59 GROSSI, V.: Appunti sulla geografia fisica del Brasile. Revista Italo-Ameri- cana, I. Roma, 1902. GROTH, P.: Ueber farblosen Cordierit aus Brasilien. Zeitschr. f. Krystallogr., VII, 594. Abstract: Neues Jahrbuch fur Mineral., 1883. II, 173, Referate. GRUNHUT, LEO: Beitrige zur krystallographischen Kenntniss des Andalu- sites und des Topases. Andalusit aus Brasilien, 120-124. Topas von Brasilien, 151-157. Zeitschrift fiir Krystallographie und Mineralogie, 1X, 1884, 120-124; 151-157. Leipzig, 1884. Abstract: N. Jahrb. f. Mineral, 1886, II, 197-202. (Topas von Brasilien, 202.) GRZYBOWSKI, JOSEHF: Die Tertiirablagerungen des nordlichen Peru und ihre Molluskenfauna. Neues Jahrbuch fiir Mineral., Beilage Band, XIT, 610-661. Stuttgart, 1899. GUERNSEY, A. H.: The Andes and the Amazon. (Chiefly abstracts from James Orton’s book of this name.) Harper’s Magazine, 1870, Xl, 344-358. New York, 1870. Few geologic notes. GUIGNET, E., and TELLES, A: Composition chimique des eaux de la baie de Rio de Janeiro. Comptes Rendus de Vl Acad. Sci., UX XXITI, 919-921. Paris, 1876. GUIGNET, E., and ALMEIDA, G. OZORIO DE: Sur un fer météorique trés riche en nickel, trouvé dans la province de Santa Catharina, Brésil. Comptes Rendus de lV Acad. Sci., UXXXITI, 917-919. Paris, 1876. GUIGNET: Sur le fer nickelé de Sainte-Catherine au Brésil. (Lettre a M. Daubrée.) Avec observations par Daubrée. Comptes Rendus de l’Acad. Sci., LX XXIV, 1507-1509. Paris, 1877. GUIGNET, E.: Sur divers échantillons d’argile et de houille du _ Brésil. Comptes Rendus de VAcad. Sci., LX XXIV, . 1326-1328. Paris, 1887. Ab- stract: The Geological Record for 1877. 200. London, 1880. GUIMARAES, ARTHUR: v. PRATES, CARLOS. GULLANA, J. K.: Brazilian carbons. Jowr. Soc. Arts, LI, 22. London, 1902. GUMBEL, C. W.: Lithologisch-mineralogische Mittheilungen. Von dr. C. W. Giimbel. I, Gesteine der Kerguelen-Insel. (II Das weisse mineral der pflanzenversteinerungen aus d. Tarentaise.) Z'schermak’s Mineralogische u. Petrographische Mittheilungen. Neue Folge. Wien, 1880, 8°, II, 186- 191. Analysis of phonolite from Fernando de Noronha, 188-189. GUNTHER, GUSTAV JULIUS: Mineral deposits of northeastern Brazil. The Mining Journal, XXXVII, 130. London, March 2, 1867. GUTHRE, F. B.: v. DAVID. GUTSMUTHS, J. G. F.: Ueber das Entstehen der Schlammbinke von den Ktistenlande Guyana. Hertha, IX, 381-393. Stuttgart, 1827. Abstract: Bull. des Sci. Nat. et de Géol., XIII, 309-310. Paris, 1828. HAACK, HERMANN: Die mittlere Héhe von Sitidamerika. Inaugural-Dis- sertation verfasst und der hohen philosophischen Fakultiit der Vereinigten Friedrichs-Universitit Halle-Wittenberg zur Erlangung der philosophischen Doktorwtirde vorgelegt von Hermann Haack aus Gotha. Halle, A. S. 8°, 88 pp. 1896. Brasilien, 32-34. HAHN, FRIEDRICH GUSTAV: Untersuchungen itiber das Aufsteigen und Sinken der Ktisten . . . Hin Beitrag zur allgemeinen Erdkunde. Habi- litationsschrift durch welche mit Zustimmung der Philosophischen Facultat der Universitat Leipzig zu seiner Sonnabend den 3 Mar., etc. Leipzig, 1879. Die Ost- und Nordktiste Siidamerikas, 93-98. HAIDINGER, WILHELM: Veriinderungen in eisen-hattigen Mineralien. Pog- gendorff’s Annalen der Physik. und Chemie, XI, 188-191. Leipzig, 1827. HAIDINGER, W.: Ueber. den durchsichtigen Andalusit von Minas Novas in Brasilien. Abhandlungen der k. bohm. Gesellschaft der Wissenschaften, VY. Folge, Band. 3, 263-270. Prag, 1844. Separate. Prag, 1844. G0) BRANNER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL HAIDINGER, W.: Vorworte zu “Ueber das Geognostische Vorkommen der Diamanten und ihre Gewinnungsmethoden auf der Serra do Grao-Mogor in der Provinz Minas Geraes in Brasilien, von Virgil von Helmreichen.” Wien, 1846. HAIDINGER, W.: Vorworte zu “Die geologische Uebersichtskarte des mittleren Theiles von Sud-Amerika”’ yon Franz Foetterle. Wien, 1854. HALFIELD, H. G. F.: Atlas e relatorio concernente 4 exploracio do Rio de Sido Francisco desde a Cachoeira da Pirapéra até o Oceano Atlantico. Levantado por ordem do governo de 8: M. Dom Pedro II, 1852-1854. 111. 57. pp. folio, 36 maps. Rio de Janeiro, 1860. Notice: Petermann’s Mitt- heilungen, 1866, 412-414. HALL, BASIL: v. JAMESON. HAMLIN, AUGUSTUS C.: Leisure hours among the gems. 8°. Boston, 1884. Brazilian diamonds, 37-46; 221-223. HANSEN, SGREN: La race de Lagoa Santa. L’homme fossile de Pontimelo. E Museo Lundii. I, paper 5, 35-37, 5 planches, 1888. Abstract of the next paper. HANSEN, SGREN: Lagoa Santa Racen. H Museo Lundii, I, paper 5, 1-34. Ill. Kjébenhavn, 1888. HANSEN, SOREN: On a fossil skull from Lagéa Santa, Brazil. Journal of the Anthropological Institute of Great Britain and Ireland, XVII, 43.- London, 1888. HARLAN, R.: Medical and physical researches or original memoirs, ete. XXXIV-XXXV. Philadelphia, 1835. Refers to evidence of elevation two degrees west of Rio de Janeiro; human bones in tufa and shells. HARRIS, G. D.: The Midway stage. Bulletins of American Paleontology, I, No. 4. Correlations made with Brazil, 40-48. Ithaca, N. Y., June, 1896. HARRIS, G. D.: Geology of the Mississippi embayment. A report on the geology of Louisiana (for 1900, 1901, 1902.) Baton Rouge, 1902. Com- parison of the Eocene of Louisiana with that of Brazil, 10-11. HARTING, P.: Description d’un diamant remarquable contenant des cristaux. Verhandlingen der Koninklijke Akademie van Wetenschappen (2 esde deel), VI, 15 pp. 4°, plate. Amsterdam, 1858. HARTT, C. FRED.: A vacation trip to Brazil. American Naturalist, Feb., 1868, I, 642-651. Salem, 1868. HARTT, C. FRED.: Resumé of a lecture on the “Growth of the South Ameri- ean Continent,” delivered before the Library Association, Ithaca, N. Y., Dec. 4, 1868. Cornell Era, Dec. 12, 1868. Also separate. Ithaca, 1868. HARTT, C. F.: (Account of a lecture on the glaciation of Brazil.) Amer. Naturalist, I, 623-624. Salem, Jan., 1868. HARTT, CH. FRED.: The cruise of the “Abrolhos.” American Naturalist, II. 85-93. Salem, April, 1869. HARTT, CH. FRED.: A naturalist in Brazil. American Naturalist, Il, 1-13. Ill. Salem, March, 1869. HARTT, C. F.: The gold mines of Brazil. The Mining Journal, XXXTIX, 849. London, Nov. 13, 1869. (Quoted from the Hngineering and Mining Jour- nal of New York.) HARTT, C. FRED.: Remarks on the Brazilian coral fauna. Trans. Conn. Acad. Arts and Sciences, I, part 2, 364-365. New Haven, 1867 to 1871. HARTT, C. FRED.: (Letter from Rio Amazonas to Prof. J. S. Newberry upon the discovery of the Itaittuba limestones.) Proc. Lycewmn of Nat. Hist. in. the city of New York, I, 89-91. New York, 1870. [Date of publication not given; title page wanting. The letter of Hartt is dated Oct. 4, 1870.] HARTT, CH. FRED.: A geologia do Parad. Reprint of a report written for the editor of the Diario do Grado Parad in 1870, at Para, Brazil. Published in the Boletim do Museu Paraense, I, No. 3, June, 1896, 257-273, with foot- note by Dr. E. A. Goeldi. Para, 1896. Abstract: Petermann’s Mittheil- ungen, page 189. Gotha, 1896. HARTT 61 HARTT, CH. FRED.: Geology and physical geography of Brazil. Maps and illustrations, pp. xxiii+ 620. Boston, 1870. Review: O Novo Mundo. lll. New York, Outubro 24, 1870. Review: Amer. Naturalist, March, 1871, V, 33-36. Annual of Scientific Discovery for 1871, 246-248. Boston, 1871. Review: Old and New, III, 91-93. Boston, 1871. Review by A. R. Wallace, Nature, II, 510-512. London, 1870. Notice: Petermann’s Mitt- heilungen, XVII, 240, Gotha, 1871. Extracts: Revue de Géologie pour les années 1869 et 1870 par M. Delesse et M. De Lapparent, 91-92. Paris, 1873. Review and abstracts: Revue de Géologie pour les années, 1871-1872, ME 15-178, (Paris, 18%. HARTT, CH. FRED.: On the geology of Brazil. Jour. Amer. Geographical and Statistical Society, II, pt. 2, 55-70. New York, 1870. HARTT, CH. FRED.: Geological discoveries in Brazil. (Extract from letter.) American Naturalist, V, 342-3438. Salem, 1870. HARTT, C. F.: Resumé of Hartt’s views of Brazilian drift, diamonds, ete. Annual of Scientific Discovery for 1871, 246-28. Boston, 1871. HARTT, CH. FRED.: Brazilian rock inscriptions. American Naturalist, V, 139-147. Ill. Salem, 1871. HARTT, CH. FRED.: Amazonian drift. American Journal of Science, third series, I (C1), 294-296. New Haven, 1871. HARTT, CHAS. FRED.: A proposed fourth expedition to Brazil. (Kor private distribution.) 4 pp: 8°. . Ithaca (N. Y.), June 16, 1871. HARTT, CH. FR.: The ancient Indian pottery of Marajo, Brazil. (Illus- trated.) American Naturalist, July, 1871, V, 259-271. Abstract under title of Reliquias de Indios na Ilha do Marajo, in Novo Mundo, Agosto 24, ise op:, ft (with 10 euts). New York, 1871. HARTT, CH. FRED.: Discovery of Lower Carboniferous fossils on the Rio Tapajos. American Naturalist, IV, 694-695. Salem, 1871. HARTT, CH. F.: On the Tertiary basin of the Maranon. American Journal of Science, IV, 53-58. New Haven, 1872. HARTT, CH. FRED.: Theory of the glacial origin of the Amazonas basin. Proceedings Boston Society Natural History, XV, 152-154. Boston, 1872. HARTT, CHAR. FRED.: Recent explorations in the Valley of the Amazonas, with map. Transactions of the American Geographical Society of New Monee rit. 231-252. Albany, 1872: HARTT, CHARLES FRED.: On the occurrence of face urns in Brazil. American Naturalist, VI, 607-610. Salem, 1872. HARTT, CH. FRED., and DERBY, O. A.: Abstract of Hartt’s reconnaissance of the Lower Tapajos and Derby’s report on the Carboniferous Brachio- poda of Itaitiba on the Rio Tapajos, Province of Para. Published in Bull. of the Cornell Univ. (Science), 1874, I, Nos. 1 and 2. American Journal Science, VIII (CVIII), 144. New Haven, 1874. HARTT, CH. FRED.: Contributions to the geology and physical geography of the Lower Amazonas. Bulletin of the Buffalo Society of Natural Science, I, 201-235. Buffalo, 1874. Abstract: Amer. Jour. Sci., CVII, 607. New Haven, 1874. Abstract: O Novo Mundo, Abril 23, 1874, IV, 128. New York, 1874. Review: Pop. Sci. Monthly, V, 758. New York, 1874. Re- view, with illustration, American Naturalist, Oct., 1874, VIII, 673-679. Review: Petermann’s Mittheilungen, XX, 440, Gotha, 1874. HARTT, CH. FRED.: Report of a reconnaissance of the Lower Tapajos. Bulletin: of the Cornell University (Science), I, Nos. 1 and 2, 11-37. Ill. Ithaca, N. Y., 1874. Abstract: Neues Jahrb. f. Min., 1877, 663-664. HARTT, CH. FRED.: Preliminary report of the Morgan Expeditions, 1870-71. Bulletin of the Cornell University (Science), I, Nos. 1 and 2, 1-10. Ithaca, N. Y., 1874. HARTT, CHAR. FRED.: Algumas consideracdes sobre o recife de Pernambuco. Revista do Instituto Polytechnico, V, Rio de Janeiro, Dec., 1875. (Dated Marco, 1876, 2d part, 21-26.) 62 BRAN NER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL HARTT, CHAR. FRED.: Relatorio preliminar dos trabalhos da Commissao Geologica na provincia de Pernambuco. 8°, 11 pp. Rio de Janeiro, 1875. Also in Diccionario Geographico das Minas do Brazil. Por F. I. Ferreira. 131-137. Rio de Janeiro, 1885. HARTT, CH. FRED.: Devonian rocks in the Amazonian valley. American Naturalist, V, 121-122. Salem, 1871. HARTT, CH. FRED., and RATHBUN, R.: Morgan Expeditions, 1870-71. On the Devonian trilobites and mollusks of Ereré, province of Para, Brazil. Ann. Lyceum Nat. Hist. of N. Y., XI, 110-127. New York, May, 1876: Brief mention Amer. Jour. Sci., CX, 154. New Haven, 1875. Abstract: Neues Jahrbuch f. Mineral., 1877, 107. HARTT, CH. FRED.: The Geological Survey of Brazil. First preliminary report made to the councellor Th. José Coelho de Almeida, Minister and Secretary of State for Agriculture. (Translated and abridged from the Portuguese by Theo. B. Comstock.) American Journal of Science, CX1, 466-473. New Haven, 1876. HARTT, CH. FRED.: Exploracoes scientificas. I. Commissio Geologica do Brazil. Catalogo da Exposicao de Obras Publicas do Ministerio da Agri- cultura, 95-106. Rio de Janeiro, 1876. HARTT, C. F.: Conferencia sobre o recife de Pernambuco, o Rio S. Francisco, a cachoeira de Paulo Affonso, etc. O Globo. Rio de Janeiro, 14 de Jan., 1876. HARTT, CARLOS FREDERICO: Inscripcoes em rochedos do Brazil. Traduc- cao de Jodo Baptista Regueira Costa. Publicagao do Instituto Archelo- gico e Geographico Pernambucano. 12 pp. 8°, plates. Pernambuco, 1895. HARTT, CH. FR.: Trabalhos restantes ineditos da Commissao Geologica do Brazil (1875-1878). Introduccao, 155-163; II, A regiio de Breves, 173- 181; III, O Rio Tocantins, 181-191; Boletim do Museu Paraense, II, No. 2, Para. 1897; V, Monte Alegré e Ereré, 322-340; VIII, A Serra de Paran- aquara, 352-358; Boletim do Museu Paraense, II, No. 3, Para, 1898. Ab- stract: Petermann’s Mittheilungen, 1898, 208. HARTT, CH. FR.: Notas biographicas sobre os trabalhos de. Ch. Fr. Hartt. Almanack Popular Brazileiro de 1903. Tambem no Diario Popular, Pe- lotas, Rio Grande do Sul, no. 156, 8 de Julho de 1903. HAUSMANN, J. FR. L., und F. WGHLER: Ueber den Anthosiderit, eine neue Mineral-Species aus Brasilien. Gottingische gelehrte Anzeigen unter der Aussicht der Kgl. Gesellschaft der Wissenschaften, I, 29 Stiick, 281- 286. Gottlingen, 1841. Also Hrdmann’s Journal fir Prakt. Chemie, XXII, 412-415. Leipzig, 1841. HAUSMANN, J. FR. L.: Tellur-Wismuth aus Brasilien. Neues Jahrb. fur Mineralogie, Geognosie, Geologie und Petrefakten-Kunde. Stuttgart, 1852, 698-701. HAUY: Mémoire sur des topazes du Brésil. Annales du Muséum National @d’ Histoire Naturelle, I, 346-352. Paris, an. XI, 1802. HAWKSHAW, Sir JOHN: Melhoramento dos portos do Brazil. Relatorio de . . . Publicacio official, 115 pp., 4°. Rio de Janeire,) ists = Portuguese and English, maps and geologic observations on the ports. An English edition of this work seems to have been published under the title of “Brazilian Harbours.” Sir John Hawkshaw’s reports are dated 15th July, 1875, folio. No date or place of publication given. HAWKSHAW, J. CLARKE: Notes on the consolidated beach at Pernambuco. Quarterly Journal of the Geological Society of London, XXXY, 239-244. London, 1879. HAY, G. U.: The scientific works of Prof. Chas. Fred. Hartt. Trans. Royal Society of Canada, 2d series, 1899-1900, V, Sec. IV, 155-165, Separate. Montreal, 1899. HEBERT—HERMETO 63 HEBERT, E.: Rapport sur la partie géologique et minéralogique du voyage de M. M. Grandidier fréres (Ernest et Alfred) dans lAmérique méridionale lu a la section des Sciences du comité des travaux historiques et des Socie- tés savantes. 8°, 5 pages, Paul Dupont (s. d.). Paris, 21 Mai, 1860. Ex- tract: Revue des Socs. Savantes, Sept., 1860. HEHL, R. A.: Das brasiliansche Kiistenland zwischen dem 21° und 23°. Stidlicher Breite. (Hine geographisch-geolische Skizze.) Petermann’s Mittheilungen, XXVIII, 443-447. Gotha, 1882. HEINTZ, W.: Ueber den firbenden Bestandtheil des Feuersteins, Cameos und Amethystes. Poggendorffs Annalen, LX, 519-527. Leipzig, 1843. Ab- stract: Jahres-Bericht uber die Fortschritte der Chemie und Mineralogie von Jacob Berzelius, XXIV, J, 300-301. Ttibigen, 1845. (Analysis of Brazilian amethyst. In the original article there is no statement about these minerals coming from Brazil. HELMREICHEN, VIRGIL VON: Reisebericht aus Minas Geraes vom 6 Mai, 1846, Berichte uber d. Mittheilungen von Freunden d. Naturwissenschaft in Wien. Vienna, 1847, II, 137-151. HELMREICHEN, VIRGIL VON: Ueber das geonostische Vorkommen der Diamanten und ihre Gewinnungs-Methoden auf der Serra do Grao Mogor. Vorworte w. Haidinger. Wien, 1846. Extract: Bull. Soc. Géol., 2me serie, IV, 157. Paris, 1847. Reference, I, 2e série, 19. HEMPEL, Dr.: (Analysis of magnesian limestone from S. Paulo.) Annales de la Soc. Géol. de Belgique. 4°, XXV, bis ler livraison, 42 Liége, 1900. HENSEL, Dr. REINHOLD: Beitriige zur niiheren Kenntniss der brasilian- ischen Provinz Sao Pedro do Rio Grande do Sul. Zeitschrift der Gesell- schaft fur Erdkunde zu Berlin, II, 227-269, 342-376. Berlin, 1867. HENWOOD, WM. JORY: Descriptive notice of the Morro Velho Mine, Prov- ince of Minas Geraes; and on the relations between the structure of the containing rocks and the directions of the shoots of gold in the Brazilian mines. Jransactions of the Royal Geological Society of Cornwall, VI, 143-146, 8°. Penzance, 1846. Also Philosophical Magazine, XXV, 341- 344. London, 1844. HENWOOD, WM. JORY: Notice of the Itabira and Santa Anna Mines in Brazil. Transactions of the Royal Geological Society of Cornwall, VI, 227-229. 8°. Penzance, 1846. HENWOOD, WM. JORY: Notice of the Descoberta Gold Mine in Brazil. Transactions of the Royal Geological Society of Cornwall, V1, 294-295. S°. Penzance, 1846. HENWOOD, WM. JORY: Abstract of a memoir on the metalliferous (gold) deposits of Brazil. Hdinburgh New Philosophical Journal, W, 61-64. Edinburgh, 1851. HENWOOD, W. J.: On the geological association of tellurium. Trans. Roy. Geol. Society of Cornwall, VII, 228-229. Penzance, 1865. HENWOOD, WILLIAM JORY: Observations on metalliferous deposits on the gold mines of Minas Geraes in Brazil. Trans. Royal Geol. Soc., Corn- wall, VIII, part I, 168-370. 8°. Penzance, 1871. HENWOOD, WM. JORY: Observations on subterranean temperature. T'rans- actions of the Royal Geological Society of Cornwall, VII, part II, 725- 732. Penzance, 1871. HENWOOD, WM. JORY: On the changes in temperature which take place at the same, and at different times on the surface and at depths of three, six and nine feet in the Canga at Agoa Quente, in Brazil. Transactions of the Royal Geological Society of Corniwall, VII, part II, 767-780. Pen- zance, 1871. HERMANN, R.: Uber den Hydrargillit von Villa Rica in Brasilien. Erdmann und Werther, Journal fiir praktische Chenvie, no. 2, 1869, 72-73. HERMETO, HONORIO: The Abaeté River, Minas. Brazilian Mining Review, I, 202-203. Rio de Janeiro, April, 1904. 64 BRAN NER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL HETTNER, ALFRED: Das siidlichste Brazilien (Rio Grande do Sul). Zeit- schrift der Gesellschoft fiir Erkunde zu Berlin, X XVI, 85-144. 8°. Ber- lin, 1891. Geological maps and section. HETTNER, ALFRED: Reisseskizzen aus Stidbrasilien. I, Ein Besuch in den deutschen und italienischen Colonien bei Porto Alegre in Siidbrasilien. Deutsche Rundschau fiir Geographie und Statistik, XIV, Heft V, Februar, 1892, 193-202; II, Besuch der Kohlenmine von Arroyo dos Ratos und der Colonien Estrella und Santa Cruz, 253-261. Wien, 1892. HETTNER, A.: Das Deutschtum in Siidbrasilien. Geog. Zeitschrift, VIII, 609-626. 1902. HEUSSER: Hin Beitrag zur Kentniss des Brasilianischen Ktistengebirge. Zeitschrift der Deutschen Geologischen Gesellschaft, X, 412-422. Berlin, 1858. HEUSSER, CH., u. CLARAZ, G.: Ueber die wahre Lagerstitte der Diamanten und anderer Edelsteine in der Provinz Minas Geraes in Brasilien. Zeitschrift der Deutschen Gesellschaft, X1, 448-466 (Bermerkungen yon G. Rose, 467-472). Berlin, 1859. HEUSSER, J. C., und CLARAZ, G.: Physikalische und geologische Forschungen im Innern Brasiliens. Petermann’s Mittheillungen, Gotha, 1859, 447-468. HEUSSER, CH., et CLARAZ, G.: Gisement et exploitation du diamant dans la Province Minas Geraes au Brésil. Extract p. M. Delesse from Ueber die wahre Lagerstiitte der Diamanten u. anderer Edelsteine in der Provinz Minas Geraes in Brasilien, von Ch. Heusser u. G. Claraz in Zeitschrift der Deutschen Geologischen Gesellschaft, XI, 448-466. Bemerkungen zur vorstehenden Abhandlungen von G. Rose, ibidem, 467. Annales des Mines, de série, XVII, 289-299. Paris, 1860. HEUSSER, J. CH., und CLARAZ, G.: Ein fernerer Beitrag zur Kenntniss des Brasilianischen Ktistengebirgs. Vierteljahrschrift der Naturforschenden Gesellschaft in Zurich, X, 60-64. 8°. Zurich, 1865. HINCHLIFF, THOMAS WOODBINE: South American sketches, or a visit to Rio de Janeiro, the Organ Mountains, La Plata and the Parana. London, 1863. Occasional observations on geology, 181-183, 216-217, 224, 252, 269, Za 29 HINTZE, CARL: Handbuch der Mineralogie. Leipzig, 1906. Brazil, Chalece- don, 1496. Brookit, 1558. HLAWATSCH, C.: Der Raspit von Sumidouro, Minas Geraes (Brasilien). Centralblatt fiir Mineralogie, Geol. und Pal., No. 14, 422-427. Stuttgart, 1905. HOCHEDER: Die urspriingliche geognostische Lagerstitte der Diamanten in Brasilien. Amtlicher Bericht ueber die einundewanzigste Versammlung deutscher Naturforsher und Aertze in Gratz, 1843. 4°, 105-107. Gratz, 1844. HOFMANN, ERNST: Geognostische Beobachtungen, angestellt auf einer Reise um die Welt, in den Jahren 1823 bis 1826, unter den Befehl des Russisech Kaiserl. Flott-Capitaines und Ritters, Herrn Otto von Kotzebue. Die Umgebungen von Rio de Janeiro. Karsten’s Archiv. fur Mineralogie, Geognosie, Bergbau und Hiuttenkunde, I, 2 Heft, 242-251. Berlin, 1829. HOLME, R. F.: A journey in the province of San (sic.) Paulo, Brazil, in July- September, 1885. Proc. Roy. Geog. Soc., TX, 108-114. London, 1887. HOLMES, JOSHPH A.: Preliminary report on the operations of the fuel- testing plant of the U. S. Geol. Survey at St. Louis, Missouri, 1905. Bul. 290, U. 8S. Geol. Survey, Washington, 1906. (Sao Jeronymo coals from Rio Grande do Sul; analyses, steaming and producer gas tests, pp. 231- 239.) HOMEM DE MELLO: v. MELLO, HOMEM DE. ea HOOFF,H.L. VAN: The drainage question of the island Marajo, s ‘Graven Tidschrift van het Koninklijke Instituut van Ingeneeors te’s Gravenia (Verhandlungen), 22-26, 1900-1901. sane HORMEYER—HUMBOLDT 695 HORMEYER, Captain J.: Siidbrasilien. Ein Handbuch zur Belehrung fiir Jedermann insbesondere fiir Auswanderer. 8°. Hamburg, 1857. I, Absch. Geographische Uebersichet von Stidbrasilien, 1-10. III, Abschnitt. von den Naturprodukten. Mineralien, 19-22. _HOVEY, E. O.: Ueber Gangdiabase der Gegend von Rio de Janeiro und tiber Salit von Sala in Schweden. T'schermak’s Mineralogische und Petro- graphische Mittheilungen, N. F., XIII, 1892, 211-221. Wien, 1892. Part on Brazil, 211-318. Separate. Wien. Abstract: Neues Jahrb. fiir Min- eral., 1894, I, 80-81. Referate. HOWORTH, HENRY H.: The glacial nightmare and the flood; a second ap- peal to common sense (ete.). In 2 vols. 8°. London, 1893. References to Brazil, 270, 272, 273, 278, 491, 495, 498. HOWORTH, HENRY H.: The glaciation of Brazil. Nature, Oct. 26, 1893, XLVITI, 614. London, 1893. HUBER, J.: Apercu géographique de la région du Bas-Amazone. Bull. Soe. Géogr., Genéve, 1900-1901, XII, 49-63. Physical features of the Amazons below Obidos. HUBER, J., et KRAATZ-KOSCHLAU, VON: Entre 1’Océan et le Rilo Guama. Bulletin de la Soc. de Géogr., III, 123-132, ill. Paris, 1901. HUBER, J.: Contribuicéo 4 geographia physica dos furos de Breves e da parte occidental de Maraj6. Bol. do Museo Paraense, III, 447-498, ill. Par&, 1901. Abstract: Annales de Geographie, XII, 291. Paris, Sept., 1903. HUBER, J.: v. KRAATZ, VON. HULL, EDWARD: The Brazilian coal-fields. The Quarterly Journal of Science, I, 387-390. London, 1864. In Portuguese—Jasigos de carvaiio de Pedra do Rio Grande do Sul e Santa Catherina. O Ausxiliador da Indius- tria Nacional, 1865, 236-242. Rio de Janeiro, 1865. HULL, EDWARD: The Brasilian coal-fields. Note from The Quarterly Jour- nal of Science, No. 2, V, I, 387-390, ill. April, 1864. Appendix H of “Brazil and the Brasilians.” By Rev. James C. Fletcher and Rev. D. P. Kidder, 9th ed., 635-637. London, 1879. HUMBOLDT, F. A.: Esquisse d’un tableau géologique de l’Amérique mérid- jonale. Journal de Physique de Chimie, d Histoire Naturelle et des Arta, LIII, 30-60. Paris, an. IX de la République (1801, v. s). [This article is the original from which the one in the next title in German, published in Allg. Geog. Ephemeriden, was taken. ] HUMBOLDT, F. A. VON: Skizze eines geologischen Schilderung des Stidlichen Amerika. Allgemeine Geographische Ephemeriden. Verfasset von einer Gesellschaft Gelehrten und herausgegeben von A. C. Gaspari und F. J. Bertuch, IX, 310-329, 389-420. Weimar, 1802. Abstract: Annalen den Berg. und Hiitenkunde von C. EB. F. von Moll, II, 22-69. Salzburg, 1803. HUMBOLDT, ALEXANDRE DRE: A geognostical essay on the superposition of rocks in both hemispheres. ‘Translated from the original French. lLon- don, 1823. Eschwege’s views on the rocks of Minas Geraes are given on pp. 116-122. HUMBOLDT, A. VON: Verkommen des Platins und Palladiums in Brasillen. Schweigger’s Journal fiir Chemie, XLV, 45. Nuremburg, 1825. Also in Pogg. Annalen, VII, 519, 1826. HUMBOLDT, ALEX. DE: Note sur le platine en Amérique, communiquée & VYAcad. Roy. des Sci., séance du 17 juillet, 1826. Le Globe (Paris), 20 juillet, 1826. Bull. des Sci. Nat. et de Géol., No. 11, 505-507. 8°. Paris, Noy., 1826. HUMBOLDT, ALEXANDRE DE: Personal narrative of travels to the equl- noctial regions of the new continent during the years 1799-1804; by Alex- ander de Humboldt and Aimé Bonpland, with maps, plans, etc., written in French and translated into English by Helen Maria Williams. 8°, VI, part II. London, 1826. Geology of the northern part of South America, 391-461. ~ 3) 66 BRAN NER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL HUNT, T. STERRY: The decay of rocks geologically considered. American Journal of Science, XX VI, 190. New Haven, 1883. HUNTER, M.: v. ROSENBUSCH and HUNTER. | HURE, Comte DE LA: v. BARIL, V. L. HUSSAK, E.: Notas petrographicas sobre os augito-porphyritos do Paranapa- nema. Boletim n. 2, da Commissio Geographica e Geologica da Provincia de S. Paulo, 35-39. 8°. S. Paulo, 1889. HUSSAK, E.: Ueber Leucit Pseudokrystalle im Phonolith (Tinguait) der Serra de Tingua, Hstado do Rio de Janeiro, Brazil. Neues Jahrbuch fur Mineralogie, 1890, I, 166-169. Briefliche Mittheilungen. HUSSAK, E.: ContribuicOes mineralogicas e petrographicas. I, Notas sobre zeolitas do Augito-Porphyrito de S. Paulo e Sta. Catharina. II, Estudo de um cascallho aurifero virgem do Valle da Ribeira. III, Pseudo-erystaes de leucita em phonolito (tinguaito) da Serra do Tingua. IV, Interessante endomorphose por accao de contacto de augito-porphyrito com grez; Rio Tieté, Estado de S. Paulo. V, Phyllitas e com magnetita do Estado de Sio Paulo. VI, Noticia resumida sobre a occurrencia de corindon em 8. Paulo. Sao Paulo, 1890. Bol. da Com. Geog. e Geol. do Hstado de SB. Paulo, n. 7, 3-40. Abstract in Amer. Jour. Sci., 3d series, XLIII (CXLIIT), 1892, 77-79. Abstract: Zeitschrift fir Krystallographie und Mineralogie, XXI, 405, 408. Leipzig, 1893. HUSSAK, E.: Mineralogische Notizen aus Brasilien, Brookit, Cassiterit, Xeno- tim, Monazit und HBuklas. - (Part I.) JUschermak’s Mineral. u. Petrogr. Mitth., N. F., XII, 357-3875. Wien, 1891. Abstract: Zeitschrift fur Kryst. and Min. (Groth), XXIV, 429-480. Leipzig, 1895. HUSSAK, E.: Ueber cubischen Pyrop und mikroscopische Diamanten aus dia- mantfiihrenden Sanden Brasiliens. Annalen des K. K. Naturhistorischen Hofmuseums, IV, 113-115. Vienna, 1891. HUSSAK, E.: I, Ueber Brazilit, ein neues Tantal-(Niob-) Mineral von der Eisenmine Jacupiranga. Sitid-Sao Paulo, 141-146. II, Ueber brasilianisehe Leucitgesteine, 146-158. III, Nochmals die Leucit-Pseudokrystall-Frage. Neues Jahrbuch fiir Mineral., 1892, II, 141-159. Abstract in Amer. Jour. Sci., XLV (CXLV), 164-165. New Haven, 1893. HUSSAK: Sobre o deposito diamantifero de Agua Suja, perto de Bagagem. Minas Geraes. Relatorio parcial da Commissaio exploradora do planalto central do Brazil, pelo Dr. Luiz Cruls, 105-128. Rio de Janeiro, 1893. HUSSAK, E.: Ueber Brazilit. Neues Jahrbuch fiir Mineralogie, 1893, LI, 89. Briefliche Mittheilungen. Abstract: Zeitschrift fur Krysti (Grau, XXIV, 164-166. Leipzig, 1895. HUSSAK, E.: Mineralogische Notizen aus Brasilien (Part II). 6. Ueber den Baddelyit (Syn. Brazilit) von der Hisenmine Jacupiranga in Sao Paulo (595-411.) 7. Ueber Schwefelkrystalle in zersetzten Pyriten der Umge- bung von Ouro Preto in Minas Geraes (411-412). 8. Ueber Skorodit- krystalle von der Gold Mine Antonio Pereira bei Ouro Preto (412-413). I'schermak’s Miner. u. petr. Mitth., N. F., XIV, 1894. 395-413. (2 plates.) Wien, 1895. Abstract of N. 6: Mineralogical Mag. and Jour. Miner. Soe., 1895, XI, N. 50, 110-111. Abstract of N. 6: Newes Jahrbuch fiir Minerat., (896, I, 214-216. Abstract: Zeitschrift fiir Krystalog. und Mineral, XXVII, 324-325. Leipzig, 1897. FAUSSAK, E.: Ueber ein neues Perowskit-Vorkommen in Verbindung mit Mag- neteisenstein von Catalao. Staat Goyaz, Brasilien. (Mit einem Holzseh- nitt.) Neues Jahrbuch fiir Mineral., 1894, II, 297-300. Abstract: Mag- netic iron ore in Brazil: Journal Iron and Steel Institute, XUVII, 286- 287. London, 1895. HUSSAK, E., and PRIOR, G. T.: Lewisite and zirkelite, two new Brazilian minerals. Mineralogical Magazine and Journal of the Mineralogical Soce., 1895, XI, 80-88. Reprint, 1-9. Abstract: Amer. Jour. Sci., 4th series, I (CLI), 71-12. New Hever, i896. HUSSAK 67 HUSSAK, HUGENIO: Sobre a occurrencia de cinabrio em Tripuhy, Minas Geraes. Revista Industrial de Minas Geraes. Anno IV, N. 23, 291-293. Ouro Preto, 20 de Abril, 1897. HUSSAK, E., and PRIOR, G. T.: On Tripubyte, a new antimonate of iron from Tripuhy, Brazil. Mineral. Mag. and Jour. Mineral. Soc., XI, 302, 1897. Separate. Abstract in Amer. Jour. Sci., 4th series, V, 1898 (CLV), 316. Abstract: Bulletin de la Soc. Francaise de Minéralogie, XXI, 86. Paris, 1898. Abstract: Zeitschrift fur Krystallog. wnd Mineral., XXXII, 185-186. Leipzig, 1899. HUSSAK, E.: Ueber ein neues Vorkommen yon Baddeleyit als accessorischer Gemengtheil der jacupirangitihnlichen basischen Ausscheidungen des Nephelinsyenites von Aln6, Schweden. Neues Jahrbuch fir Mineralogie, 1898, II, 228-229. HUSSAK, E., and PRIOR, G. T.: On Derbylite, a new antimonotitanite of iron from Tripuhy, Brazil. Mineralogical Magazine, 1897; XI, N. 52, 176-179. Reprint, 1-14. Abstract: Newes Jahrbuch fur Mineral., 1898, II, 196-197. Referate. Abstract: Bulletin de la Soc. Francaise de Minér- alogie, XXI, 133-134. Paris, 1898. HUSSAK, E.: Ueber eine merkwiirdige Uimwandlung und secundiire Zwillings- bildung des Brookits von Rio Cipo, Minas Geraes, Brazilien. Neues Jahr- buch fir Mineralogie, 1898, II, 99-101, plate. Stuttgart, 1898. Abstract: Zeitschrift fir Krystallog. und Mineral., XX XIII, 180. Leipzig, 1900. HUSSAK, E.: Das Zinnober-Vorkommen von Tripuhy in Minas Geraes, Bra- Silien. Zeitschrift fiir praktische Geologie, Februar, 1897, 65-67. Berlin, Soi. Abstract: Zeitschrift fur Krystaltlog. und Mineral., XXXII, 185. Leipzig, 1900. HUSSAK, E.: Der goldfiihrende, kiesige Quarzlagergang von Passagem in Minas Geraes, Brasilien. Zeitschrift fur praktische Geologie mit beson- derer Berticksichtigung der Lagerstittenkunde, Oktober, 1898, 345-357. figures. Berlin, 1898. Partial abstract by W. Lindgren: Transactions American Institute of Mining Engineers, 1900, XXX, 626-642. Ill. New York, 1901. Abstract: Zeitschrift fir Krystallog. und Mineral., XX XIII, 207-208. Leipzig, 1900. HUSSAK, E., and PRIOR, G. T.: On Senaite, a new mineral belonging to the Iimenite group from Brazil. Mineralogical Magazine, June, 1898, XII, N. 54, 30-32. London, 1898. Abstract: Bulletin de la Société Francaise de Minéralogie, X XI, 178. Paris, 1898. Abstract: Zeitschrift fiir Krystallo- graphie und Mineralogie, XXII, 272-274. Leipzig, 1900. HUSSAK, EUGEN: Mineralogische Notizen aus Brasilien (Part III). 9. Hin Beitrag zur Kenntniss der sogenannten “Favas” der brasilianischen Dia- mantsande, 334-341. 10. Die Mineralischen Begleiter des bahianischen Diamants, 342-859. Tschermak’s Mineral. u. petrograph. Mitth., N. F., XVII, 1898, 3384-359. Wien, 1899. HUSSAK, E.: Ueber ein leukokrates gemischtes Ganggestein der Serra de Caldas, Brasilien. Neues Jahrbuch fiir Miner., 1900, I, 22-27. Stuttgart, 1900. HUSSAK, E., and PRIOR, G. T.: Florencite, a new hydrated phosphate of aluminium and the cerium earths from Brazil. Mineralogical Magazine, XT; N. 57, 244-248. London, 1900. Abstract: Amer. Jour. Sci., CLX, 404. New Haven, 1900. Abstract: Zeitschrift fiir Krystallog. wnd Mineral., XXXVI. 165-166. (Groth.) Leipzig, 1902. HUSSAK, E.: Ueber Chalmersit, ein neues Sulfid der Kupferglanzgruppe von der Goldmine “Morro Velho” in Minas Geraes, Brasilien. Centralblatt f. Van. G. wv. Pat., 1902, N. 3, 69-72. Stuttgart, 1902. Abstract: HEnglish translation in Transactions of the Institution of Mining Engineers, XXYV, 793. Newcastle-upon-Tyne, 1904. HUSSAK, E.: Nota sobre a chalmersita, mineral do grupo da Chalcosina, encontrado na mina do Morro Velho. Annaes da Hscola de Minas, No. 86, S1-97, Ouro Preto, 1903. 68 BRAN NER—BIBLIOGRAPHY OF THE GEOLOGY OF BRAZIL HUSSAK, E.: Sobre a raspita do Sumidouro, Este de Minas Geraes. Avnnacs da IHscola de Minas, No. 6, 99-103. Ouro Preto, 1903. HUSSAK, E., und RHITINGER,. J.: Ueber Monazit, Nenotim, Senait und nattirliches Zirkonoxyd aus Brasilien. Zeitschrift fiir Krystal., XXXVII, 550-579. Ill. Leipzig, 1903. Abstract: lining Magazine, XIII, 398. London, 1903. HUSSAK, E.: Ueber den Raspit von Sumidouro, Minas Geraes. (Brasilien.) Centralblatt fiir Alineralogie, 1903, 723-725. Stuttgart. 1903. Abstract: Zeitschrift fur Krystal. und Mineral, XW1, 647-648. Leipzig, 1906. HUSSAK, E.: Ueber die Mikrostructur einiger brasilianischer Titanmague- teisensteine. Neues Jahrbuch fiir Mineralogie, Geologie und Paleontologie. Jahrgang, 1904. I Band, 94-113. Stuttgart, 1904. HUSSAK, E.: Ueber das Verkommen von Palladium und Platin in Brasilien. Siteungsberichten der K. Akademie d. Wissenschaften in Wien. Math. nat. Klasse Bd., CXIII, Abh. I. Wien, Juli, 1904. Abstract under title: Occurrence of Palladium and Platinum in Brazil. Amer. Jour. Séi., CLXIX, 397-399. May, 1905. HUSSAK, E.: Mineralogische notizen aus Brasilien. (tber einen neuen Chondritfall, nahe Uberaba in Minas Geraes, tiber Nephrit von Baytinga in Bahia und tiber Hamlinit aus diamant ftihrenden Sanden von Dia- mantina, Minas Geraes.) Annalen des K. K. Naturhistorischen Hofs- museums, XIX, Heft I, 85-95. Wien, 1904. Abstract: American Journal of Science, CLXIX, 202-203. Feb., 1905. HUSSAK, E.: Ueber Atopit aus den Manganerzgruben von Miguel Burnier, Minas Geraes, Brasilien. Centralblatt fii Mineralogie, Geologie und Paleontologie, 1905, No. 8, 240-245. Stuttgart, 1905. HUSSAK, BUGEN: Ueber das Vorkommen von gediegen Kupfer in den Dia- basen von Sado Paulo. Centralblatt fiir Mineralogie, Geologie und Patdon- tologie, 1906, No. 11, 333-335. Stuttgart, June, 1906. HUSSAK, EUGEN: Ueber Gyrolith und andere Zeolithe aus dem Diabas yon Mogy-guasst, Staat Sao Paulo, Brasilien. Centralblatt fiir JLlineralogie, Geologie und Paldontologie, 1906, No. 11, 330-332. Stuttgart, June, 1906. HUSSAK, HUGEN: Ueber die chemische Zusammensetzung der Chalmersit. Centralblatt fur Mineralogie, Geologie und Paldontologie, 1906, No. 11, 332-333. Stuttgart, June, 1906. HUSSAK, E.: Uber die Manganerzlager Brasiliens. Zeit. fiir Prakt. Geol., XIV, Juli, 1906, 237-239. : HUSSAK, E.: Uber das Verkommen von Palladium und Platin in Brasilien. Zeit. fur Prakt. Geol., XIV, Sept., 1906, 284-293. Translated by M.. A. Ri Lisboa and published under the title, O palladio e a platina no Brasil. Annaes da Escola de Minas de Ouro Preto. no. 8, 77-188. Ouro Preto (19066). Separate. Resumé: Neues Jahrb. f. Min., II, 1905, 346-348. HUSSAK, E.: Uber die Diamantlager im Westen des Staates Minas Geraes und der angrenzenden Staaten Sitio Paulo und Goyaz, Brasilien. Zeit. fir Prakt. Geol., XIV, Okt., 1906, 318-333: Abstract: Newes ania Min., 1908, I, 169. , HUSSAK, E.: Uber die sogenannten ‘‘Phosphat-Favas” der diamant ftiihrenden Sande Brasiliens. V'schermaks IMlineralogische wu. Pet. Alitteilungen. N. F., X XV, 335-344. Wien, 1906. Abstract: Bul. Soc. fr. de Mineralogie, XXIX, 368-370. Paris, 1906. HTWSSAK, E.: Ueber Gyrolith und andere Zeolithe aus dem Diabas von Mogy- guasst, Staat Sao Paulo, Brasilien Ueber die Chemische Zusammensetzung des Chalmersit Ueber das Verkommen von gediegen Kupfer in den Diabasen von Sido Paulo. Centralblatt fiir Min. Geol. u. Pal. Jahrg., 1906, no.. 11, 330-335. Stuttgart, 1906. HUSSAK, E.: v. OLIVEIRA. HUTTON—I HERING 69 HUTTON, JAMES: Of the flexibility of the Brazilian stone. (Read Feb. 7, 1791.) Transactions of the Royal Society of Edinburgh, III, 86-94. Edin- burgh, 1794. Under title of “Brazilian stone,” quoted from Hncyclopedia Perthensis or Universal dictionary of arts, science, 2d ed., IV, 308-3809. Edinburgh, 1816. HYATT, ALPHEUS: Report on the Cretaceous fossils from Maroim, Province of Sergipe, Brazil. Hartt’s geology and physical geography of Brazil, 385-393. Boston, 1870. HYATT, ALPHEHUS: The Jurassic and Cretaceous Ammonites collected 1a South America by Professor James Orton, with an appendix upon the Cretaceous Ammonites of Prof. Hartt’s collection. Proc. Boston Soc. Nat. HST... “VIL, 365-372. —Boston, 1875. HYATT, ALPHEUS: Pseudoceratites of the Cretaceous. Monograph XLIV, U. S. G. S. Washington, D. C., 1908. Vascoceras Harttii from Sergipe, 103. Plate XIV. IDDINGS, J. P.: Rhyolite tuff from Pernambuco. Bull. Geol. Soc. Amer. vol. 13, 84. Rochester, 1902. IHERING, H. VON: Die Lagoa dos Patos. Deutsche Geogr. Blitter. Bremei, VIII, 193 ff. 1885. IHERING, H. VON, und LANGHANS, P.: Das siidliche Koloniengebiet von Rio Grande do Sul. Petermann’s Mittheilungen, XXXIII. 289-302, 2 Karten, 328-348. Gotha, 1887. IHERING, H. VON: On the ancient relations between New Zealand ail South America. TJ'ransactions of the New Zealand Institute, 1891, XXIV, N. 18, 431-445. Auckland, 1891. IHERING, H. VON: Sobre las antiquas conexiones del continente Sud-Ameri eano. Revista Argentina de Historia Natural, I, 121-122. Buenos Aires, 1891. THERING, H. VON: Nuevos dados sobre las antiquas conexiones del conti nente Sud-Americano. Revista Argentina de Historia Natural., I, 280-282 Buenos Aires, 1891. IHERING, H. VON: Die Insel Fernando de Noronha. Globus, INIT, N. 15. 225-230. Braunschweig, 1892: TIHERING, H. VON: Ueber Binnen Conchylien der Kiistenzone von Rio Grand do Sul. Archiv f. Naturg., LX, 37-40. Berlin, 1894. IHERING, H. VON: As ilhas oceanicas do Brazil. .).fets wus sce bts ee lace Bye eels be law eles base lw oe 147 Ae eralowan compared with Kansan... 2.23 tease cc 5 dc ee we ees ws 147 Piniiimpenciacial interval, the Peorian... 0220.00. ec ee ee eee es 148 OME UBT MCI (Maree etree foie) eo ohara ee Sia ko 3 Ga ws URLS are eta EW oho GMS s Siete @whaleles 9 ¢ 149 Characteristics of the Wisconsin compared with those of the Iowan.. 149 aoe ISconsim: compared with the INansanm 2.030... 6 ce esc es we ee ee 151 0 SEELSEIESI (86/506 ig SIR REIL SR eee ea a a a2 INTRODUCTION More than once your speaker has had occasion to say that Iowa was exceptionally fortunate in its location with reference to the movements and marginal limits of the successive ice invasions of the Glacial epoch, and that the state therefore offers unusual facilities for the study of the 1 Manuscript received by the Secretary of the Society January 11, 1909. X—BULL. GEOL. Soc, AM., Vou. 20, 1908 (133) 134 S. CALVIN——PRESENT PHASE OF PLEISTOCENE IN IOWA relative age and differential characters of the several sheets of drift. It is not to be understood from this, however, that in the favored area selected for discussion there are no unsettled Pleistocene problems. Im- portant questions, many of them, are still waiting for solution; but while knowledge is admittedly incomplete in many particulars, it may be worth the while at this stage in the interpretation of Pleistocene records to set out the points that seem to be indicated with a fair degree of clear- ness. In the discussion which is to follow no attempt will be made to give an historical outline of the growth of knowledge relative to the problems under consideration, such as would be appropriate in an address dealing finally with the subject; nor will any effort be made to assign the degree of credit which belongs severally to the masters who have worked so effectively and so illuminatingly in the Pleistocene field. It will be enough to say that Pleistocene geology, as represented in lowa, is in- debted to a host of men, among whom may be mentioned Chamberlin, McGee, Bain, Upham, Leverett, Udden, Beyer, Macbride, Shimek, and Savage; while of men who have contributed to our knowledge of Pleisto- cene conditions outside of Iowa the number is still larger. Noteworthy, epoch-making, have been the scholarly contributions of such students of Canadian geology as Hinde, Coleman, and Dawson. The fact that within the limits of Iowa at least five distinct drift sheets are clearly differentiated, a number greater than may be readily distinguished in any corresponding area elsewhere, affords some justifica- tion for limiting the discussion to so small a portion of the glaciated area. The problems of this limited field, however, are the problems of the continent, so far as the age of ice is concerned. PLEISTOCENE PROBLEM OF TWENTY YEARS AGO AND OF TODAY Less than twenty years ago there was at least one eminent geologist on this side of the Atlantic who denied the evidence of any glacial invasion of any of the present habitable portions of North America. There were many who admitted the evidence of one, but only of one, episode of glaciation, and some of this class still survive. A few men whom we all honor were laboriously collecting facts which proved that glaciers had overridden portions of the continent at least twice; and they discussed phases of glaciation which, in accordance with the best knowledge of the time, were known as the “First” and “Second” glacial epochs. Upper and Lower till became familiar terms in the literature of Pleistocene geology. Now we point to evidence showing five ice invasions, possibly six; and only a few, if any, are left to question the adequacy of the evidence. As THE PROBLEM TWENTY YEARS AGO AND TODAY 135 stated at the outset, the location of Iowa with reference to the known ice movements was exceptionally favorable. ‘The two earlier sheets passed across the state, covering the whole surface except the small part of the Driftless area which lies in the northeastern corner. ‘Terminal margins of the known three later sheets come within the limits of Iowa, and the movements were so distributed that no one of the ice lobes obscured the records of its predecessors. There are, therefore, miles upon miles of well defined border nes along which it is possible to compare directly the characteristics of one drift sheet with another; and there are inter- glacial deposits bearing testimony to the nature of the faunas and floras | and climatic conditions which characterized the central portions of the continent during the long, mild intervals between the stages of glaciation. It is the purpose of this address to set forth what the Pleistocene records of such an area more or less definitely prove. FIRST AND SECOND GLACIAL EPocHs AND FIRST INTERGLACIAL INTERVAL GENERAL CHARACTERISTICS During the early Pleistocene, as already noted, there were two stages of glaciation which affected larger areas in Iowa than any of those which followed. So far as present knowledge goes, these were the real first and second Glacial epochs of which we have discovered records in the interior of the continent; but later investigations, as has happened before, may change the ordinal positions here assigned them. No conceivable discov- eries, however, can possibly modify the fact that these two invasions were distinct glacial episodes, separated one from the other by a long interval; for here are two sheets of drift distinctly different, recording the coming and going of two ice caps, while soil bands, weathered zones, buried peat bogs, forest beds, pond silts, and stream gravels lying between the till sheets tell of interglacial conditions. The widely distributed peats and forests of the intercalated beds furnish a record of the plants which flourished during the interval ; and within the last four months the gravels between the older drifts in Harrison, Monona, and other western counties have contributed the first important information from the area under consideration concerning the first interglacial fauna. The earlier of the two older drifts is known in the geology of Iowa as the pre-Kansan or sub-Aftonian, and the later of the two, adopting the name proposed by Chamberlin, is the Kansan. Whether the pre-Kansan should be correlated with the Albertan of the north, or with the Jer- seyan of the east, or with anything else now known in America or in Europe, is a question that need not be discussed. It is enough for the 136 S. CALVIN——-PRESENT PHASE OF PLEISTOCENE IN IOWA present that here are two sheets of drift recording two distinct stages of glaciation, with abundant evidence of an interval between them. PRE-KANSAN OR SUB-AFTONIAN DRIFT The pre-Kansan is dark blue, almost black in color. It has a habit peculiarly its own of breaking into small fragments or crumbling into finer particles on continued exposure. At the classic locality near Afton Junction this older drift is exposed in the west bank of Grand river, a mile below the station, and is overlain by more than 30 feet of water-laid gravels which were at one time worked for railway ballast. Overlying the gravels is a heavy deposit of typical Kansan till. The same gravels are exposed in a great ballast pit at Afton Junction, from which locality came the name “Aftonian,” given by Chamberlin to the gravels as well as to the entire interval of which they form part of the record. Four | miles farther east, near Thayer, is another pit of Aftonian gravels. At all the localities named the Aftonian beds are covered with from 20 to 30 feet of characteristic Kansan (plate 1, figure 1). KANSAN DRIFT The Kansan differs from the pre-Kansan physically. It is light blue or gray in color when unweathered: it is cut by numerous intersecting, vertical joints, and it breaks into large, irregularly shaped angular blocks. That there are physical differences may be demonstrated wherever there are opportunities for comparison, but a concrete case may be cited in the section illustrated by Savage in his report on Tama county. Here the two older drifts are separated by a mere thin soil band. The lower, as shown in the figure, is compact but relatively plastic, and the steam shovel passing through it left the imprint of its cutting margin; the bed above the Aftonian soil, hard almost as sun-baked bricks, and jointed vertically, yielded to the force of the shovel by breaking into irregular, prismatic blocks. Physical differences, constant and consistent, mark these two beds of till as distinct (plate 1, figure 2). . AFTONIAN INTERVAL The Aftonian was a real interglacial interval. It was a long interval, but the data which might furnish a basis for estimating its actual or comparative length are as yet wanting. With the possible exception of the “forest bed” which McGee, in his early work on the Pleistocene, had found everywhere between his “Upper and Lower till,” the gravels at Afton Junction and Thayer were the first of the Aftonian deposits to be 2 Geology of Iowa, vol. xiii, page 231. BULL. GEOL. SOC. AM. VOL. ZO, 908, PIL. 1 HPIGURE 1.—V1iIEW IN TIZP GRAVEL PrrT At AFTON JUNCTION, IOWA Showing (1) Aftonian gravels more than 20 feet in thickness, rising a few feet above the railway grade; (2) Ikansan drift much weathered and stained in the upper zone; (3) loess. PIGuRH 2.—SECTICN IN RAILWAY CuT IN 'LOLEDO VOWNSHIP, Tama County, Iowa Showing well defined soil-band between the pre-Kansan and the Kansan drifts GLACIAL. PHENOMENA AT AFTON JUNCTION AND IN TAMA COUNTY, IOWA pay te, ee VMOI ‘NISM13O GNV AS TIVA INNOSSIN YVAN VNSWONSHd IVIOV19 VILIp UBMOT (ef) ESpoq UrTuO, Py Uo POALIOp .‘stoppuoqd puws,, oIep OM) YIM JIPIp uUBsurny (GZ) {Sool} JO SHUN PoAtosoard-TfoM PUR SSO [Sot] SU[VUOT UBOSN [LOU PUL UBTPRUUTBUT JO TOQ(UINU OFIR, V popyTOTA OALY STOARLE (HIM Jvod uLpuOysy (P) poMOoys WO STUY) YSoaty Wor A OSOL IWhMp UBsuvyy YPRoud ov uvpuoJJY JO sPOAVLE PUL SPURS Poppod-sso1d Supsodxgy GO) NEEM SIM NT NOMLOUG—"G GUT] VMO]T SXOUTVIVA IMNOSSTIN UVAN Oi WAVUD NO" TE map Z "Id ‘B06L ‘0% “IOA "WV “OOS *1039 °110N8 AFTONIAN INTERVAL 137 definitely recognized. ‘They were the first of these deposits to be assigned to their true position in the Pleistocene column. In themselves these gravels afforded little information concerning the time interval to which they belong, farther than that the pre-Kansan ice had disappeared from the region and that great floods, distributing the usual terrace materials, poured along the drainage courses. In a paper on the Aftonian gravels, in the Proceedings of the Davenport Academy of Sciences, volume X, it was assumed that the floods carrying the materials of which the beds are composed had their origin in the melting of the pre-Kansan ice, and that these deposits represented simply the closing phase of the pre-Kansan stage of glaciation. ‘The assumption was based wholly on the ground that it was difficult otherwise to account for streams of such volume and persistency as would be required to transport and deposit the enormous quantities of gravel found in Union county. Now, however, it seems that investigations made by Shimek during the past four months may make it necessary to modify the view expressed in the Davenport Academy paper. Similar materials, quite as extensive as the beds at Afton Junc- tion and Thayer, lying between the dark pre-Kansan below and typical Kansan above (plate 2, figure 1), are found along the Boyer, the Soldier, the Little Sioux, the Maple, and practically all the streams which drain the western slope of Iowa. In these new localities the Aftonian gravels have yielded the remains of a fauna representing river mollusks of mod- ern species on the one hand and extinct terrestrial mammals on the other. Both mollusks and mammals are found in such abundance, at such widely scattered localities, and in such a state of preservation as to make it certain that the fauna was contemporaneous with the deposition of the gravels. They are not remains washed out of previous glacial or pre- glacial formations. The mammals include forms which have been re- ferred by some recent American writers to Hlephas primigenius and Elephas imperator; there is the common mastodon, Mammut ameri- canum; there are two horses resembling the Hquus complicatus and Equus occidentalis of Leidy; a large stag related to Cervalces; an unde- termined cavicorn ruminant and one or two other unidentified forms. All the probiscideans are represented by teeth, and in addition to the teeth there are the lower jaw of the large elephant, the left ramus and symphysis of the mastodon, a perfect tibia, a nearly perfect humerus, a femur nearly four feet in length, and yet lacking the proximal end; a scapula which was perfect when taken from the pit, but was allowed to go to pieces for lack of care; fragments of tusks up to four feet in length, a few vertebrae, some pieces of the pelvis and unrecognized frag- ments. ‘There are a number of teeth from both horses, besides a large 138 S. CALVIN—-PRESENT PHASE OF PLEISTOCENE IN IOWA collection of equine bones which may belong to either of the two species. There are vertebre, scapule, and caleanea; nearly all the limb bones are represented, including metapodials and phalanges. The large amount of the material and its unexpectedly perfect state of preservation, these are the impressive facts, and these indicate very clearly that the fossils are not mere chance intrusions, but are the remains of a fauna which was living in the-region at the time the gravels were accumulating. Further- more, it will be evident that the presence of this fauna, whether we take into consideration either its molluscan or its mammalian phase, is incon- sistent with the view that the floods indicated by the deposits were fed by melting glaciers. When this fauna lived and the gravels were depos- ited there had been time enough since the disappearance of the pre- Kansan ice to allow the region to become clothed with an abundant vege- tation suitable for the support of the elephant and the horse; and the temperature of the streams did not preclude the presence of fypes of mollusks which find a congenial habitat in the rivers of modern Iowa. The Afton Junction-Thayer beds have yielded fossils, quite a number; but among these are such forms as Favosites from the Silurian and Pla- centiceras from the Upper Cretaceous. Among the other things there occurred some foot bones of a small, slender-limbed horse less than half the height of our domestic species. The stage of equine development indicated by the bones showed that the animal could not be older than the Phocene; but it was assumed that, like the other fossils from the same beds, it must be pre-Glacial. In the light of the new finds in Har- rison and Monona counties we may conclude that this beautiful little Equus was probably contemporary with the deposition of the gravels, and that there may have been at least three species of Aftonian horses. Concerning the precise age of these widely distributed gravels between the Kansan and the pre-Kansan, it may be said that the Aftonian faunas show that they were not laid down at the beginning of the interval, when the earlier ice-cap was melting. Extensive weathering and alteration of the materials, especially in the upper zone, show that they were not depos- ited at the close of the interval, when the Kansan ice was advancing. Forest material and remnants of an old soil, observed by Chamberlin and McGee between the gravels and the overlying drift, support the conclu- sion based on weathering. All lines of evidence now indicate that the beds in question record conditions which existed at some time during the progress of the interval, neither at its beginning nor at its close, but in the light of present knowledge the precise age of the deposits can not be more definitely stated. The soil band in the railway cut near Tama, already noted, is one of AFTONIAN INTERVAL 139 many instances of the same kind and it tells the story of an interglacial interval as clearly and forcefully as the gravels and their remarkable faunas. Interglacial peat beds confirm the testimony of the old soils and buried gravels. One of the best. known examples of peat at the Aftonian horizon is that in the Oelwein cut. The organic deposit is three feet in thickness ; it contains the remains of a tamarack forest, together with great quantities of pressed moss, almost as fresh as when it grew; the whole is underlain by dark pre-Kansan and covered with 20 feet of Kansan and Jowan till. The Aftonian peat bed described by Savage in the eleventh volume of the Proceedings of the Jowa Academy of Science is, in some respects, even more important than that at Oelwein; the fauna and the flora of the deposit have been worked out in greater detail. Additional testimony to the same effect is found in the buried forests encountered in digging farm wells over practically the whole of Iowa. Facts relating to this phase of the subject, so far as concerns some of the northeastern counties of the state, were collected by McGee, and are set forth in great fullness and with masterly clearness in his memorable paper, “‘7'he Pleistocene History of Northeastern Iowa.” 'The Aftonian, more than any other of the interglacial intervals, was a time of luxuriant forests, and forest beds are at present unknown at any horizon in the region studied by McGee except that between the Kansan and pre-Kansan drifts. In view of the evidence, clear and positive, and multiplied over and over again, we can but repeat that the Aftonian was a real interglacial interval, an interval of long duration, an interval of moist climate and swollen streams, an interval when the winters’ cold was not so severe or the snow- fall so excessive as to preclude the continued occupation of the region by the great stag, the horse, the mastodon, and the elephant—an interval when the modern types of river mollusks flourished in the streams of Towa. PHYSICAL RELATION OF THE KANSAN TO THE OLDER DEPOSITS The Kansan till, which overlies the Aftonian beds, records what now appears to have been the maximum phase of Pleistocene glaciation. Kan- san drift is superficial, except for a partial covering of loess over southern and western Iowa. Its physical properties, color, texture, and toughness, which have often been described, distinguish it readily from till of any other age. In some cases the Kansan ice plowed into the Aftonian gravels, broke them up while frozen, and transported masses varying in some of their dimensions from a few inches to more than one hundred feet. It follows, therefore, that sand and gravel boulders, derived from Aftonian beds and incorporated with other morainic detritus, are among (140 — s. CALVIN—-PRESENT PHASE OF PLEISTOCENE IN IOWA the notable features of the Kansan drift, whether seen in the Oelwein cut in northeastern Iowa (plate 2, figure 2) or in the large cuts near Thayer, in the southwestern part of the state (plate 3, figure 1). Near Missouri valley, at one of the newly discovered exposures, there is a great mass of transported and badly distorted Aftonian, the full size as yet unknown, but it has been worked quite extensively as an independent gravel pit. The strata, originally horizontal and cross-bedded, are faulted and folded, and in some cases they are tilted through an angle of more than ninety degrees. On the side showing the greatest deforma- tion the pit has been worked out up to a vertical wall of Kansan drift; and in this body of till, against which the gravels, standing on edge, sud- denly end, we recognize the instrument used by the Kansan glacier in plowing into the Aftonian beds and breaking them into blocks. Here is a mass of deformed and displaced Aftonian, an enormous sand and gravel boulder, and here, in the exact position assumed while the work was being done, is the agent through which was transmitted the shove and the thrust recorded in the distorted gravels (plate 3, figure 2). Masses of the dark pre-Kansan, rolled and kneaded and showing the effect of the tremendous squeeze and push of a continental glacier, also occur as boulders embedded in the Kansan. ‘These sharply defined masses of Aftonian gravels and pre-Kansan till, large or small, incorporated in the Kansan, add confirmation to the evidence, if confirmation is needed, that this till and these gravels existed as distinct geological formations before the Kansan ice invaded Lowa. RELATIVE AGE OF KANSAN AND PRE-KANSAN While the Kansan is younger than the pre-Kansan, younger than any of the Aftonian deposits, it is not possible to say, even approximately, how much younger it is. The gravels were greatly altered by weathering before the Kansan drift was deposited, the oxidation and kaolinization requiring time. It required time to clothe the cold, bare surface of the pre-Kansan drift with forests, and forests did grow luxuriantly, genera- tions of them probably, during the Aftonian interval. The accumulation of the Aftonian peat required time. Time was needed for the develop- ment and distribution of the aquatic and terrestrial Aftonian faunas. But, granting all the time required for these things, it is still probable that the length of the Aftonian interval was equal to but a small part of post-Kansan time. If the time since the Kansan be represented by unity, the time since the pre-Kansan would be represented by one and a small fraction. On the other hand, the Kansan till is certainly very much older than any of the later drift sheets, and fortunately the data on BULL. GEOL. SOC. AM. | VOLS 20, 1908, PL. & IMG GiI0} I ——\Vinohyy IN, RAKED? “Olea NOVNG “WMéiAaviaiR Showing a moderately large mass of Aftonian gravel, with smaller “sand boul- ders’ trom the same formation, incorporated in the Kansan drift Hicure 2.—Tar MCGAVERN GRAVEL PIT NAR MISSOURI VALLEY Showing (A) a very large ‘‘sand boulder’ of Aftonian gravel, crushed, faulted, and deformed, and (K) the face of a mass of Kansan drift, the agent through which the crushing was accomplished. GLACIAL PHENOMENA NEAR THAYER AND MISSOURI VALLEY, IOWA ILLINOIAN DRIFT AND SECOND INTERVAL Ta] which estimates of relative age may be based are fuller and more satis- factory than in the case of the pre-Kansan intervals. ILLINOIAN DRIFT AND THE YARMOUTH OR SECOND INTERGLACIAL INTERVAL The drift which followed the Kansan, the third in the known order, is the Illinoian, and the interval between the Kansan and the Illinoian is the Yarmouth. For the last two names, Illinoian and Yarmouth, and for the first discussion of the records to which they are applied we are indebted to Leverett. ‘The Yarmouth seems to have been the longest of » the interglacial intervals. The Illinoian glaciation, which followed the Yarmouth, affected directly only a small part of Iowa. Ice from the Labradorean center came from the northeast, crossed the channel of the Mississippi, and pushed a broad lobe into a relatively small area in south- eastern Iowa. If glaciers corresponding to the known Ilhnoian were developed in the Kewatin region, they terminated in that part of the glaciated area which was subsequently covered with Iowan or Wisconsin drift, or with both. Ilhnoian of Kewatin origin has not so far been anywhere recognized. ‘The strip of territory occupied by the Ilhnoian drift west of the Mississippi river is rarely more than 25 miles in width, and is limited to portions of Scott, Muscatine, Louisa, Des Moines, and Lee counties. In this area it overlaps the Kansan, and at various points near the margin of the lobe wells have gone through Illinoian into Kan- san, revealing a zone of weathering, a definite soil band, extensive alluvial deposits, and well developed peat beds between the two bodies of drift. The facts have been worked out by Leverett, and are recorded in volume V of the Proceedings of the Iowa Academy of Sciences and in his mono- graph on the Lllinois glacial lobe. Owing to the greater recency of the Illinoian as compared with the Kansan, the amount of valley cutting since it was deposited has been much less than in the Kansan, and the opportunities for observing the Yarmouth interglacial deposits in natural exposures are fewer than in the case of the Aftonian. The Yarmouth, however, is a true interglacial interval. It had its forests and its terres- trial faunas, as shown by the sections near the village of Yarmouth, which Leverett has recorded. The faunas embraced some modern mam- mals, for the peat encountered in digging one of*the wells furnished bones of the modern wood rabbit and the common skunk. The mammals of the Aftonian beds so far collected are all extinct. The relative length of the Yarmouth interval may be determined ap- proximately by comparing the changes which time has wrought in the Illinoian drift sheet with the changes recorded in the adjacent and sub- 142 S. CALVIN—-PRESENT PHASE OF PLEISTOCENE IN IOWA jacent Kansan. The great body of the Illinoian, where unaltered, is yellow in color; the Kansan, as already noted, is blue. The Illinoian surface shows practically no erosion, except at the margin or along the larger stream valleys; over more than three-fourths of its area there is little or none of the sculpturing effect of surface drainage. At its mar- gin, or near the larger streams which have been successful in keeping their valleys scoured out, there is some water carving, but the narrow, rain-cut gulches are steep, and they terminate at most only a few miles back from the foot of the grade, in the uninvaded plateau. All the char- acteristics of the Ilhnoian may be studied between Durant and Daven- port, or between Columbus Junction and Morning Sun or Mediapolis. Weathering, as expressed by oxidation, hydration, and kaolinization of feldspars, affected the deposit to a depth of 3 or 4 feet. Compare now with the Kansan. In the older drift the changes due to weathering, what- ever the names employed to denote processes of alteration, have gone down to depths varying from 12 to 30 or 40 feet, and that in a stiffer and more impervious clay than the Illinoian. The whole surface over hundreds of square miles is carved by storm waters into well rounded ridges and deep, wide-open ravines. ‘The lateral ravines on the side slopes of the larger drainage valleys have very gentle gradients as compared with those in the Tllinoian, and they reach back into the interstream areas, up to the sum- mits of the rounded divides. Excepting in a few limited localities where there are very wide or relatively low spaces between the larger systems of drainage, there is none of the original drift plateau left. In his paper in the Proceedings of the lowa Academy of Sciences, volume V, Leverett cites evidence to show that quite an amount of erosion had probably taken place in the surface of the Kansan before the [llinoian drift was depos- ited. The amount of erosion indicated is much more than has been effected in the general surface of the younger of the two drifts we are comparing since the disappearance of the Illinoian ice. But even if we disregard this particular bit of evidence of probable pre-[llnoian erosion of the Kansan, it is still true that, under similar conditions as to prox- imity to the main drainage courses and altitude above them, the amount of erosion in the Kansan is very much more than twice as great as in the Illinoian. On the basis of erosion alone we are justified in concluding that the Yarmouth interval was longer than all post-[llinoian time. Considering the effects of weathering and general alteration, the evi- dence leads to the same conclusion. The first few feet below the surface should undergo alteration rapidly. This zone is exposed more directly to the atmosphere, to storm waters, to thawing and freezing, to the chem- ical reactions of carbon dioxide, humic acids, and other products of de- caying vegetation ; to the direct and indirect effects of burrowing animals, THIRD INTERVAL 143 such as gophers, ants, and earthworms; and changes may go on with comparative rapidity. Whatever the time required to produce weather- ing to a depth of 4 feet, the time required to bring about changes to a depth of 8 feet will be very much more than twice as great. The Kansan is altered to an average depth of more than 8 feet; the weathered zone of the Illinoian rarely exceeds 4 feet; again we conclude that the Yarmouth interval was more than equal to all post-Ilinoian time. THIRD INTERGLACIAL INTERVAL, THE SANGAMON Another interglacial interval, the Sangamon of Leverett, followed the withdrawal of the Illinoian ice. ‘There are no very satisfactory deposits of Sangamon age in Iowa, but the interval is very clearly represented at a number of points in Illinois. This interglacial horizon, like the Aftonian and the Yarmouth, is indicated by its buried forests, its soil and weathered zones, its pond silts, and its peat beds. One of the most instructive sections showing the relations of the Sangamon stage is seen in a railway cut on the Toledo, Peoria and Western railway, 7 miles east of Peoria. ‘The exposure is described by Leverett in his monograph on the Illinois glacial lobe, and is illustrated in plate XI, figure B, opposite page 128, of the work cited. The section shows in ascending order (1) typical yellow Llhnoian till; (2) stratified silt, evidently laid down in a quiet, shallow pond; (3) peat, with great quantities of tamarack roots, recording conditions which followed the silting up of the pond and its conversion into a marsh; (4) loess, probably Iowan or early Peorian; (5) Wisconsin drift, and (6) Wisconsin gravels. Numbers 2 and 3 rep- resent the Sangamon. ‘The weathered zone at the top of the Illinoian, and underneath loess which may be of Peorian age, is a feature seen at numberless points in Iowa as well as in Illinois, and represents changes which were wrought, in part at least, during the Sangamon interval. Muscatine, Montpelier, and Davenport may be named among the Iowa localities where this phase of the subject may be studied. At the brick- yard east of Mud creek, in Muscatine, the Illinoian is overlain by beds of stratified sand which, there is little doubt, belong to the Sangamon ; they may represent, however, only the beginning of the Sangamon, the melting phase of the Illinoian ice. In turn the sands are overlain by loess. Iowan DRIFT EXTENT OF THE IOWAN Following the Sangamon interval there was a recurrence of glacial conditions, and the Iowan drift, the fourth of the known till sheets, was distributed over a portion of the previously glaciated area. The Iowan 144 S. CALVIN——PRESENT PHASE OF PLEISTOCENE IN IOWA ice, so far as it affected Iowa, came from the northwest, as the Kansan and the pre-Kansan had done in the earlier stages of the Pleistocene; but the Iowan glaciers stopped a long way short of the limits reached by their ancient predecessors from the Kewatin centers. ‘The main body of the Iowan failed to reach Iowa. A broad lobe was all that passed the northern boundary of the state, and this covered an area approximately 100 miles in length from northwest to southeast and 80 miles in width. The area thus affected lies in the northeastern quarter of Iowa, in a re- gion that had not been reached by the Illinoian. It was the eroded and weathered surface of the old Kansan, therefore, that this ice invaded and on which the Iowan was deposited. The latest observations show that within the limits of the area under discussion the Iowan nowhere touches or overlaps the Ilinoian. Along a line drawn from Marshall county to the northwest corner of Worth the Lowan is itself overlapped by the younger Wisconsin. RELATIVE AGE OF THE IOWAN The Iowan is a very young drift when compared with the Lhnoian. Its surface remains as the ice left it. Not even along the larger water- courses has it been trenched to any notable extent, as is so conspicuously the case in the Illinoian. Effects of erosion are practically zero, or they were about zero until the agriculturist came to disturb the adjustments of slope and run-off and vegetation, which maintained a fair degree of topographic stability. The opening of artificial drainage courses, the destruction of the prairie sod, and the general cultivation of the surface have resulted in more erosion during the last fifty years than had taken place under natural conditions during all the millenniums since this till was deposited. And yet, with all the help that destructive art has fur- nished, the surface as a whole remains essentially unchanged. If we may judge by the comparative erosion in the Jowan and the I[llinoian, the Sangamon interval, though shorter than the Yarmouth, was fairly long. If the interval is measured by the comparative extent of the changes wrought by weathering, the conclusion is the same, but the con- viction is stronger. The brown or red weathered zone of the Illinoian is from 3 to 4 feet in thickness. Jn the Iowan there is a deep, black soil developed on the surface, but changes due to weathering can not be recog- nized. In particular instances where the Iowan till is thin, the whole thickness of the deposits belonging to this stage is included in the humus layer; but where the thickness amounts to several feet, apart from the dark soil band there are no changes which can be measured or described. The till presents the same color and has the same composition from its RELATIVE AGE OF THE IOWAN 145 most deeply buried parts up to the grass roots in the humus layer at the surface. The amount of weathering in the Iowan must be expressed by a number that is very near to zero. How many times greater must be the number which would fitly express the amount of Illinoian weathering which has affected a zone 3 or 4 feet in thickness? And if we had these numbers correctly determined, would their relative values correctly ex- press the relative lengths of post-Illinoian and post-Iowan time? If so, the Sangamon was very long, and the Illinoian is many times as old as the Iowan. It may not be inappropriate here to say that the question of leaching is not emphasized in this discussion. The amount of lime carbonate present in any drift is a criterion of small value in determining its age. Quantitatively, the calcareous material included in the different drift sheets as an original constituent differed very greatly. For exam- ple, the Iowan drift was never as calcareous as the Kansan. There is very little limestone flour even in its deeper parts, and there are prac- tically no limestone pebbles. Within the limestone areas of the region which it traversed, the Iowan ice seems to have been too thin to cut down to bedrock. All the characteristic materials which it carried, all except what may have been picked up from the Kansan, were probably derived from an area near the origin of the ice-sheet, an area of coarse crystalline rocks. On the other hand, the Wisconsin drift is charged to excess with limestone flour and limestone pebbles, greatly outranking in the matter of these constituents all the other glacial deposits of the Mississippi valley. Again, we find that the same till sheet varies in respect to lime content in different localities, the old Kansan having originally had vastly more calcareous material in the southwestern part of the state than in the northeast. Furthermore, the presence or absence of lime carbonate near the surface of any particular drift sheet may depend locally on movements of ground waters. Without movement there can be no transfer of the soluble contents of the drift from one place or from one zone to another. Again, a drift sheet may be never so young—it may have been finished but yesterday—but if the ice which transported it traversed a region containing nothing but siliceous rocks, the most industrious wielder of the acid bottle could get no reaction. The acid bottle may have its place, but it lacks something yet of being an instru- ment of precision when used to determine the relative age of drift. The bearing of all this is obvious, and it is all told to emphasize the point that, owing to its original composition, the superficial portion of the Towan drift, or any other portion of it, for that matter, may give little or no reaction with acid; but the drift is nevertheless young. Measured 146 S. CALVIN——-PRESENT PHASE OF PLEISTOCENE IN IOWA by any trustworthy criterion, the Sangamon interval, though shorter than the Yarmouth, was long. UNDULATING SURFACE OF THE IOWAN The surface of the Iowan is more undulating than that of the Illinoian. The amount of material carried by the Iowan ice within the territory covered by the Iowan lobe was very small: the deposit is thin and meager as compared with the great thickness of the Kansan till; it is very much thinner than even the Illinoian. There was not enough of the Iowan completely to disguise the topography of the eroded surface upon which it was laid down. ‘The thickness varies from zero on the summits of the old Kansan ridges to a probable maximum of 20 feet over the Kansan valleys. ‘There are large spaces, scores of them, within the Iowan area where there is not now a trace of Iowan drift. The Iowan ice passed over them, but left none of its load. Such a space occupies a few square miles east and north of Independence, in Buchanan county. Another, a larger one, lies south of Lime creek, in Cerro Gordo county. There are many similar cases, especially near the marginal limits of the Iowan lobe, and all demonstrate the fact that Iowan drift may be absent from a fairly large area and present in all the area surrounding it. For ex- ample, the Iowan drift is absent for a mile or more east of Independence, but at the old Illinois Central gravel pit, 4 miles east of the city, the Towan is about as well developed.as it is anywhere in the state. Here the drift in question overlies weathered Buchanan gravels, post-Kansan in age, which have been worked for railway ballast; it varies from 1 foot to 8 feet in thickness (plate 4, figure 1). The meagerness of the Iowan till, even when normally present, and its entire absence from large areas which must have been covered with Iowan ice have made it very difficult in some localities to determine the exact position of the border of the Towan lobe. ‘The Iowan border, as drawn on the drift maps published in the reports of the Iowa Geological Survey, in the light of clearer knowl- edge of the peculiarities and behavior of the Iowan ice, will require a considerable amount of rectification. INDIVIDUAL CHARACTERISTICS Notwithstanding its meagerness and occasional absence, the Iowan drift exists, and it has its distinctive individual characteristics. It is light yellow in color, hghter than the Llinoian. It is less calcareous than any of the other drifts. Its characteristic boulders are large, lght- colored, coarse-grained granites, rich in feldspar, and ranging from 10 or 12 to 40 or 50 feet in diameter. These great rough boulders, numerous BULL. GEOL. SOC. AM. - VOL. 20, 1908, PL. 4 HiGuURH 1.—VIEW IN AN ABANDONED GRAVEL Pir NEAR Doris, BUCHANAN CouNTY, IOWA Below the markers is a thick bed of Buchanan gravels, only partially exposed. When the pit was worked the gravel was taken out down to the blue Kansan till. Above the markers is a bed of typical Iowan, S to 10 feet thick. The Iowan becomes thinner toward the left and thicker toward the right. FIGURE 2.—THE YOUNG, UNERODED IOWAN Drirr PLAIN, WITH CHARACTERISTIC GRANITE BOULDERS. VIEW EAST OF WINTHROP, IOWA GLACIAL PHENOMENA IN BUCHANAN COUNTY, IOWA BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 5 FIGURE 1.—SHALLOW, NARROW TRENCH OF THE SHELL ROCK RIVER, IN CERRO GORDO County, Iowa Showing a characteristic young Iowan stream FIGuRE 2.—RHLBOW LAKE AND PART OF THE MORAINE SOUTH OF RUTHVEN, IOWA Illustrating some characteristic topographic features of the very young Wisconsin drift. GLACIAL PHENOMENA IN CERRO GORDO AND PALO ALTO COUNTIES, IOWA INDIVIDUAL CHARACTERISTICS OF THE IOWAN 147 in some localities, lie on the surface or are but partly embedded, and they contribute striking and diagnostic features to the Iowan landscapes (plate 4, figure 2). Their prominence above the surface in a region which has suffered no erosion has led at least one geologist to conclude that they represent superglacial material carried by the Iowan ice and gently lowered on the surface as the glacier melted. Setting aside the obvious difficulties in the way of accounting for superglacial drift on the surface of a continental ice-cap traversing a region of low relief, there is evidence in the large proportion of planed specimens, great and small, that the Iowan boulders were transported beneath the ice. To meet a demand for suitable blocks for bridge piers and heavy foundations, many of the larger boulders were actually quarried in Buchanan, Black Hawk, and other counties; and in a majority of cases, when the last pieces were lifted out of the shallow pits in which the granites lay, the lower surface showed a face, flattened and scored, many feet in diameter. These boulders were probably embedded completely in the lower surface of the ice; the ground moraine otherwise was very thin; the granites now stand out conspicuously above the surface, because the subglacial drift, as a whole, was insufficient in amount to conceal them. DRAINAGE COURSES IN THE IOWAN A discussion of the general surface features of the Iowan should in- clude some reference to the drainage courses. ‘These add some special characteristics to the young drift plain. In many instances, owing to the meagerness of the drift, the streams recovered their old, pre-lowan valleys after the disappearance of the ice; but some were obliged to seek new courses across the drift plain, and these now flow in shallow trenches almost at the level of the cultivated fields (plate 5, figure 1). There are here no valleys in any proper sense, no river bluffs, no floodplains; the Iowan streams are young; they have barely commenced to cut their val- leys; they have very few tributaries; the lateral drainage is effected by flow along the broad sags of the original surface, instead of being limited to definitely cut channels; over extensive areas the drainage is sluggish and imperfect. AGH OF IOWAN COMPARED WITH KANSAN After this review of its general characteristics we may compare the Towan drift with the Kansan, giving especial attention to criteria indica- tive of age. The differences seem almost immeasurably great. With the exceptions already noted—namely, low-lying areas or the axes of very broad divides—the whole of the original Kansan plain has been completely carved and sculptured by flowing water and a miniature type 148 S. CALVIN——PRESENT PHASE OF PLEISTOCENE IN IOWA of mature erosional topography has been developed. There are no un- drained upland areas: the rain-cut trenches have invaded every part of the original plateau. In parts of southwestern Jowa the rivers—for example, the Nodaway, at Hepburn, in Page county—have eroded valleys in the Kansan drift 200 feet in depth and 3 or 4 miles in width. At Iowa City the lowa river has made a valley 80 feet in depth since the Kansan, and half of this depth has been cut in Devonian limestone. All the streams of the Kansan area and practically all parts of the Kansan surface tell the same consistent story; all record a long period of active erosion. Along the lowan-Kansan border there are many points where the differences are strikingly brought out. On one side of a fairly defi- nite line the topography is water-carved; on the other side it is ice- moulded; on one side a series of rounded, billowy, loess-covered ridges fitting into a.dendritic system of broadly open, erosion-cut ravines; on the other a great boulder-dotted plain, untouched by erosion, over exten- sive areas as level as a floor. The amount of erosion over the general surface of the Kansan is many times as great as that over the general surface of the Jowan. If differences in the amount of erosion may be taken as a fair measure of the differences in the age of two drift sheets, then the Kansan is certainly a hundred times as old as the Iowan. If the two drifts be compared with reference to the magnitude of the changes brought about by weathering, a similar conclusion is reached. The great thickness of the altered and oxidized zone in the Kansan was noted in making comparisons with the I|linoian, and reference has also been made to the inappreciable amount of weathering in the Iowan. To say that weathering in one case is one hundred times as great as in the other is to make a very conservative estimate. If weathering is a measure of age, we may repeat the statement already made, that the Kansan is certainly one hundred times as old as the Iowan. FouRTH INTERGLACIAL INTERVAL, THE PEORIAN The Peorian interglacial interval, which followed the Iowan ice stage, was very short, and at its close a fifth ice-sheet, coming from the Kewatin center, flowed into Iowa and distributed the body of till called the Wis- consin. As in the case of the Iowan, it was only a terminal lobe of the Wisconsin that crossed the Iowa-Minnesota line. In the main, the Wis- consin lobe lies to the west of the Iowan; it overlaps the Iowan for some distance along its eastern edge: in general it overlies loess-covered Kan- san. The southern extremity of the Wisconsin drift lobe is at Des Moines, and within the city limits excavations for various purposes have given sections showing (1) profoundly altered, oxidized and weather- FOURTH INTERGLACIAL INTERVAL 149 stained Kansan drift; (2) fossiliferous loess containing Succinea, Pupa, and other terrestrial mollusks belonging to species still living in the local- ity, and (3) Wisconsin drift, with boulders 3 to 4 feet in diameter. Many of the exposures were made in grading streets or excavating for foundations, but a section that will not be concealed for some time may be studied at the tile works in East Des Moines. Still better sections were seen a few years ago in the fresh cuts made by the Great Western railway in the western edge of the Wisconsin lobe, near Carroll. These were studied in detail by Shimek, and showed (1) typical Kansan ox- idized and otherwise weathered for some feet below the original surface; (2) an old blue, fossiliferous loess, with a weather-stained band at the top and many ferruginous cylindrical concretions throughout its whole thickness; (3) a much younger, unaltered, yellow post-lowan loess, and (4) Wisconsin drift. There are no known sections showing direct con- tact of the Wisconsin with the Iowan, but the yellow loess on which the Wisconsin rests at Carroll and at so many other points in Illinois and Iowa has, on good grounds, been correlated with events which followed the disappearance of the Iowan ice. The loess of certain parts of the Mississippi valley is a deposit belonging to the Peorian interglacial in- terval, and the Wisconsin lies on top of it. The changes whch took place in the lowan drift during this entire interval are too small for numerical or relative expression. The interval, compared with the Yarmouth or the Sangamon, was very short. The Iowan is probably not more than twice as old as the Wisconsin. WISCONSIN DRIFT CHARACTERISTICS OF THE WISCONSIN COMPARED WITH THOSE CF THE IOWAN The Wisconsin drift sheet is something very distinct from the Iowan. It differs in composition, being excessively calcareous, while the amount of lime carbonate in the Iowan, in any form, is very small. The calca- reous constituent of the Wisconsin drift takes the form of fine limestone flour mixed with the clay, together with great numbers of limestone peb- bles. It differs also in color; the color is a lighter yellow. Furthermore, the Wisconsin differs from the Iowan in habit. The Iowan drift is thin and meager, and fails completely over large areas toward the margin of the lobe. From areas even in the interior of the lobe it may he absent. The Wisconsin drift is more abundant; it completely disguises the pre- Wisconsin topography; in most cases it becomes thicker toward the margin. The ice of this stage seems to have been heavier and more energetic; it scoured down to bedrock in the limestone areas north of XI—BULL. GEOL. Soc, AM., Vou. 20, 1908 150 S. CALVIN——PRESENT PHASE OF PLEISTOCENE IN IOWA Towa; it carried quite a load out to its margin; it constructed morainic knobs and ridges, such as Pilot Knob and its associates in Hancock county, 100 feet in height in some cases, with material actually thrust out and heaped up around the edge of the ice. Besides being a moraine- forming ice-sheet, the Wisconsin is responsible for the largest amount of Pleistocene gravels to be found in the state. The streams and surface sheets of water were large in volume and were loaded to their full capae- ity. Whole townships are covered with coarse outwash gravels in con- tinuous sheets, and gravel trains occur along all the drainage courses leading out from the edge of the Wisconsin drift. In a wide belt along the western border of the lobe, in Osceola, Dickinson, Palo Alto, and Clay counties, the surface is marked by hundreds of knobs and ridges of gravel having the form of kames or eskers. This feature may be said to culminate in Ocheyedan mound in Osceola county, a noted and con- spicuous gravel kame so prominent that it commands attention from every part of the area surrounding it within a radius of 25 miles. The many scores of other gravel ridges along this western border of the Wis- consin are only less interesting than Ocheyedan mound because they are smaller in size. In marked contrast with all this evidence of kame-forming and general gravel-depositing habit of the Wisconsin are the meager indications of outwash from the Iowan. The Iowan ice was certainly very thin and in- efficient near its margin, and most of the water produced by melting may have been disposed of by evaporation. Along some of the streams which drain the Iowan lobe and flow beyond its margin there are a few sand terraces, usually small; but on the upper lowa river, near Decorah, there are extensive deposits of fresh sand which have been correlated with the melting of the Iowan ice. Down in the valley of the Iowa river at lowa City, in the relatively young gorge which has been excavated since the Kansan, there are sand terraces of Iowan age beneath river silt and ordi- nary loess. On the whole, however, the evidence of floods of any force or volume, flowing from the wasting Iowan ice, is almost zero. All the known deposits referable to the melting phase of the lowan are sands; never do they assume the character of gravels such as would require the agency of energetic currents. Comparing the surface features in the larger way, the differences in these two drift sheets in Iowa are still obvious and decisive. Apart from the gravel kames and morainic knobs already noted, there are differences due to the larger quantity of material carried to the outmost limit of its territory by the Wisconsin ice. Owing to greater thickness of the glacial deposit, there are, as a rule, no signs of the old Kansan topography ex- WISCONSIN DRIFT rye pressing itself through the younger drift mantle. The surface records simply the eccentricities of ice deposition, and nothing else. There are many square miles of level plain without signs of knobs or ridges, but with thousands of acres of shallow, reedy marshes and ten of thousands of acres of flat meadow land, above which rise, with scarcely perceptible slope, to a height of very few feet, the low swells which may be cultivated under natural drainage conditions. Efforts at reclamation by means of artificial ditches have been made in places with greater or less success; but so broad are the level plains, so slight the grade, and so far away the possible outlet for the ditch waters that the problem of drainage is a serious and difficult one. Lakes ponded in depressions among the mo- rainic knobs (plate 5, figure 2) and saucer-shaped kettle-holes, varying from a rod or two to half a mile in diameter, distributed over the flatter parts of the lobe, are other characteristic surface features of the Wiscon- sin drift. There seem to be two phases of the Wisconsin represented in lowa, and these may possibly correspond to the Shelbyville and Bloomington sheets differentiated in Ilhnois by Leverett. The well defined moraine passing southward through Dickinson, Clay, Buena Vista, Sac, and Car- roll counties marks the western edge of the ice during the latest phase of the Wisconsin. But outside the moraine west of Ruthven, in Osceola, O’Brien, Clay, and some of the adjacent counties, there is an area occu- pied by drift having all the characteristics of the Wisconsin, except that there are few morainal features: and marshes and kettles are much less numerous than in the inter-morainal portion of the lobe. This area be- longs to the Wisconsin; the drift may represent the earlier Wisconsin ; but it is quite possible that the position of the moraine may indicate sim- ply a recession and halt of the ice, and that the Wisconsin drift in Iowa is, after all, but a single sheet. But whether there be one or two phases of the Wisconsin, this last of our known drift sheets presents characteristics of extreme youth. THE WISCONSIN COMPARED WITH THE KANSAN As you know, the old sub-Aftonian or pre-Kansan drift is exposed only in stream valleys or in artificial excavations. It gives character to the surface of no large area as do the several till sheets which followed it. It was everywhere covered by the widespread mantle of Kansan drift, and erosion and weathering, so far as it was concerned, came to an end at the time of the second ice invasion. In the case of each of the other drifts, there are extensive areas over which they have been exposed to the action of the atmosphere and drainage waters ever since they were deposited ; Lo? S. CALVIN——PRESENT PHASE OF PLEISTOCENE IN IOWA and it is to this fact that we owe the possibility of making estimates as to relative age. The oldest glacial deposit in which the accumulating effects of continuous time is recorded is the Kansan; the youngest is the Wisconsin ; and between the two the differences in age seem almost im- measurable. Comparing the weathering and erosion in the central, inter- morainic part of the Wisconsin with the corresponding evidences of change in the Kansan, the differences must be expressed by a number greater than one hundred. It cannot be affirmed that changes have progressed at a uniform rate in each bed of drift or during all parts of Pleistocene time; but, making every possible allowance, there is no escape from the conclusion that the Pleistocene was a long, long period, com- pared with which the recent period, or post-Glacial time, would have to be represented by a very small fraction. ‘The Yarmouth, or even the Sanga- mon interval, was long as compared with the post-Wisconsin. CONCLUSION The facts presented in this address show that the history of the re- : markable period we call the Pleistocene was vastly more complex than was suspected by any one twenty years ago; but, complicated as this history now seems, it is possible that we have just made a beginning in recover- ing the leaves of the fuller and larger history which will include Pleisto- cene details at present unknown and undreamed—details which will clearly illuminate every successive step in the evolution of the world as we know it today from that which existed at the close of the Tertiary. In the presidential address on Pleistocene history which will be delivered before this Society twenty years hence there will probably be descriptions of drift sheets—now unknown because completely buried under younger deposits—dividing the long Yarmouth and Sangamon intervals; there will be more interglacial phases, fuller discussions of interglacial faunas and floras, more significant details of every sort and kind. Some who are here today may have the privilege of listening to that address and of joining with the younger men of the time in expressing surprise at the meagerness of the knowledge of Pleistocene history possessed by geolo- gists during the first decade of the twentieth century. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 153-170 APRIL 3, 1909 Hike! CALCAREOUS FOSSILS AND THE EVOLUTION OF THE LIMESTONES? BY REGINALD A. DALY (Read by title before the Society December 29, 1908) CONTENTS Page coo EPEC IG DOI 9, Bod Ges dtc eit CLS aS >, a i eas ree an ee 153 mere Meg UME TIVEL SOIC wa6 ole. le sald a ale aes cd eslere oye a oe Se ao ete es 155 Pecos Oim the POSt-VUrOnian FEVOIULION. 2.055. 22s eae ee ee cs ee ee eats 156 TLE IE Melee CGH N52 WM Ghee a a 157 Comparison of the Ottawa and other rivers................ Wig bis evciecaneuae 160 Chemical contrast of pre-Cambrian and later river systems............. 161 Variations in the calcium supply during and after the pre-Cambrian...... 162 See PARC CLIC UEC OUS MOSSILG sic cuss) araloceie omits oe gis « ovee g svellee's a Guehe eae 8 be 6 162 Origin of the pre-Cambrian and early Paleozoic limestones and dolomites. 163 Average ratio of calcium to magnesium in the limestones of the different LGTEITOM ofA Gist SAgRI St Se hae al ira Ou eee rane aara ietosa By Aho Siptoneiers saae outer 163 Summary on the origin of the pre-Devonian limestones.................% 167 Testimony of the grain of the pre-Ordovician limestones................ 167 RIPPED ZL) Grin SLIGHT AE ses Wa Ege I etre A ce ara 168 INTRODUCTION Jt may be assumed that the average water of the ocean has not been of the same composition in any two of the geological periods. The ocean has had a chemical evolution. Though the amount of water may have remained tolerably constant from the pre-Cambrian time to the present, it seems certain that the amount and character of the mineral matter dissolved in the ocean must always have been changing. The inflow of river-borne salts has varied in rate according to the area of the lands and according to the kinds of rocks exposed to subaerial erosion during the different periods. On the other hand, there are reasons for believing that the precipitation of salts from the sea-water (including biochemical precipitation) has occurred at variable rates. The composition of the existing average sea-water may conceivably be dependent on four other factors: a, the primitive condition of the ocean before the regime of the rivers was established; 6, the direct solution of submarine rock by sea- water; c, the emission of acids and soluble salts at voleaniec vents; and, 1 Manuscript received by the Secretary of the Society January 8, 1909. XII—BuLL. Grou, Soc, AM., VoL. 20, 1908 (153) 154. R. A. DALY—THE EVOLUTION OF THE LIMESTONES d, the inflow of salts-laden “juvenile” waters in the form of submarine springs which are fed from the earth’s interior. In tracing the history of the ocean water, the variations in the supply of river-borne salts and in the rate of chemical precipitation of salts are the factors which seem to permit of at least a crude analysis. They are likewise the factors most important in their bearing on the origin of the calcareous fossils in the rocks and on the origin of the limestones and dolomites. These two problems have been attacked again and again, but rarely, in either case, on the basis of a variable content of mineral matter in the oceanic solution. The writer has discussed at some length the hypothesis that the secre- tion of calcareous hard parts by marine organisms was first made possible as a result of the increase of the land areas during the post-Huronian orogenic revolution.? That enlargement of the continents caused a great increase in the annual supply of river-borne salts to the ocean. The sup- ply was specially enlarged by the upturning and erosion of the thick lime- stones which had been deposited on the sea-floor of earher pre-Cambrian time. ‘These lhmestones are regarded, on the hypothesis, as precipitates of calcium and magnesium carbonates, thrown down when the river- borne salts diffused to the ancient sea-bottom. The chief reagent for the precipitation is considered to be the ammonium carbonate generated by the decay of animal matter.* It is further postulated that in pre-Cam- brian time the active scavenging system had not yet been evolved; that therefore the amount of decaying animal matter on the pre- Cambrian sea-floor was vastly greater than the amount now allowed to decay on the bottom of the ocean. The smallness of the annual supply of river-borne calcium salts, coupled with this specially rapid precipita- tion of calcium carbonate, is supposed to have kept the pre-Huronian ocean nearly limeless; only the minute traces of calcium salts contained in the river waters as they diffused to the sea-bottom would be found in the ocean of that time. At the bottom the water would be practically limeless. The nearly limeless condition of the surface water was changed by the extensive orogenic and epeirogenic movements of post-Huronian time. In the Cambrian period the animal species had begun to armor them- - selves with the new material, henceforth present in the sea-water in suffi- cient amount. The primitive chitinous shell now became strengthened with phosphate and carbonate of calcium, and in the Ordovician many species had adopted the armor or skeleton of pure calcium carbonate. 2 American Journal of Science, vol. xxiii, 1907, p. 93. * The reaction is the same as that occurring within the living mollusc as it “secretes” its shell. See R. Irvine and G. S. Woodhead, Proceedings Royal Society of Edin- burgh, vol. 16, 1889, p. 352. THE TERRANE AND THE RIVER SOLUTE DD The Ordovician and Silurian rocks were therefore the first to be charged with calcium carbonate shells and skeletons in large numbers. The hypothesis further states that not only a large part, if not all, of the pre-Cambrian limestones and dolomites, but, as well, the limestones and dolomites of the early Paleozoic formations, are chemical precipi- tates thrown down by ammonium carbonate. This precipitation grew slower in proportion to the development of the fishes and other efficient bottom scavengers. When the scavenging system became well established calcium salts could, for the first time, accumulate in the ocean water in excess of the needs of lime-secreting organisms. Thereafter the marine limestones have heen largely formed from the deébris of the hard parts of animals and plants. : The original paper contains a discussion of various tests of the sug- gested hypothesis. These included, first, the witness of laboratory ex- periments; secondly, the testimony of the Black sea—a basin where modern limestone is being deposited by the organic alkali because of the lack of a scavenging system over most of the basin-floor; and, thirdly, the lithological evidence of pre-Cambrian sedimentary deposits. The present paper is intended to suggest the value of additional evidence based on the chemistry of the rivers draining pre-Cambrian terranes. In addition, the testimony of the microscope to the chemical origin of thick Cambrian and pre-Cambrian limestones is briefly outlined, and the systematic chemical variation of the limestones through geological time is quantitatively discussed. THE TERRANE AND THE RIVER SOLUTE ~The influence of the kind of rock traversed by a river on the chemical composition of that river is clearly illustrated by Hanamann’s careful investigation of the Bohemian rivers.*- His results are in part sum- marized in the following table (1), in which the content of calcium and the content of magnesium in streams issuing from different rock forma- tions are given: TABi ET a a = : WEMarT ae Caleium in | Magnesium | Ratio of Waters from— parts per | in parts per ealeium to | million. | million, magnesium, 01S ir el, a ee oe (Pallas Deo Bee 2 ll ee eee ae Se) yo ee 2.37: 1 “S225 SUL SUIS ee aa ee cee Cae SO 2.48: 1 LEP EEG. « mccain anne oko CR etree eee 68.84 19.76 3.49: 1 Cretaceous (partly limestone) ............ 133.38 ole 36 4.25: 1 3J. Hanamann: Archiv Natur. Landesdurchforschung Boéhmen, vol. 9, no. 4, 1894; vol. 10, no. 5, 1898—quoted in F. W. Clarke's “‘Data of Geochemistry,” Bulletin no. 330, U. S. Geological Survey, 1908, p. 79. Cf. also A. L. Ewing, American Journal of Science, series iii, vol. 29, 1885, p. 29. 156 R. A. DALY—THE EVOLUTION. OF THE LIMESTONES Since these various waters were working under lke climatic (solu- tional) conditions, the control of the terrane over the amounts of dis- solved calcium and magnesium is manifest. After a detailed study of the question, Dubois estimates that on an average, ceteris paribus, rivers flowing entirely over silicate rocks carry only one-tenth as much calcium carbonate as rivers flowing entirely over limestone, and remarks that even this fraction is almost certainly too large. According to his estimates, only one-thirtieth of the calcium car- bonate annually entering the sea has been newly formed through the decomposition of silicates. The rest is derived from the direct solution of limestone. He has further concluded that in early Archean time the world’s river system probably carried each year not more than one- eighth as much carbonate to the ocean as the existing river system carries.* EFFECTS OF THE POST-HURONIAN REVOLUTION From the lithological nature of the Huronian and pre-Huronian for- mations as well as from other general considerations, we may believe that the Huronian and pre-Huronian lands were chiefly composed of acid, granitic and schistose rocks. The post-Huronian orogenic reyolu- tion lifted very thick and extensive (Grenville and other) lmestones, as well as huge masses of basaltic rocks above baselevel.° From the quanti- tative studies of Hanamann and Dubois we may believe with equal readiness that the annual supply of calcium to the ocean after the reyo- lution was from two to five or more times that characteristic of Huronian and pre-Huronian time. The revolution must have had another important effect—in decreasing the sea-bottom area on which the precipitation of calcium carbonate took place. The researches of the “Challenger” chemists show that at depths greater than 3,000 fathoms, little or no solid calcium carbonate can re- main on the sea-floor. In fact, the tendency to the complete solution of this salt is strong at all depths greater than 2,500, if not 2,000 fathoms. This means that the permanent removal of calcium carbonate from the present oceanic solution through the decay of animal carcasses at the bottom seems to be possible only in about one-half of the existing ocean basin—say 70,000,000 square miles. This area is partly neritic (depths less than 200 fathoms) and partly bathyal (depths between 200 fathoms and 2,000 fathoms). On account of the higher temperatures and lower bottom pressures (pressure increasing the solubility of the carbonate) of 4E. Dubois: Proceedings of the Section of Sciences, Kon. Akad. van Wetenschappen, Amsterdam, vol. 3, pp. 119-126. °>Cf. F. D. Adams: Journal of Geology, vol. 16, 1908, p. 617. EFFECTS OF THE POST-HURONIAN REVOLUTION 157 the shallower water, we should expect the rate of chemical precipitation of calcium carbonate at the bottom to be concentrated in the neritic (epicontinental) and shallower bathyal regions, a total area of, say, 35,000,000 square miles. Let us assume that previous to the post-Huronian orogenic revolution the whole area of the lands was 20,000,000 square miles, or about 20/55 of the present area. On the view that the ocean has had a nearly con- stant volume from Huronian times to the present, it follows that the Huronian sea was largely epicontinental for an area of more than 35,000,000 square miles; so that the area of rapid chemical precipitation of calcium carbonate was about twice as great as the possible present area. Let us also assume that the post-Huronian revolution increased the land area to 55,000,000 square miles, which is roughly the present area of the lands.® The annual rate of the supply of calcium to the ocean was, on these assumptions, increased from (55/20 K 2==) 5.5 to (55/20 & 5 + =) 14+ times by the post-Huronian crustal movements. But the sea- bottom area over which the chemical precipitation of calcium carbonate was compelled was halved by those movements. ‘Thus the post-Huronian conditions favoring the possibility that a part of the river-borne calcium could remain-~in solution in the ocean were from (5.5 K 2==) 11 to (14 xX 2==), 28 or more times more effective than the pre-Huronian conditions. Although little stress can be laid on any particular figure embodied in the foregoing conclusions, this rough analysis serves to illustrate the strength of the probability that the prodigious crustal movements of the post-Huronian and pre-Cambrian interval made a comparatively rapid and quite drastic change in the chemical condition of the ocean. ANALYSES OF THE OTTAWA RIVER The view that the supply of calcium to the ocean reached a maximum rate in post-Huronian and pre-Cambrian time is based on some specula- tion. Apparently more certain are the grounds for believing that the 8 Joly’s well known estimate of the age ot the ocean as about 90,000,000 years seems much too low for the needs of the geologists. His view that the sodium borne into the ocean by the rivers during past time is nearly all represented in the present sea-water is apparently one of the soundest in dynamic geology. The chief source of doubt as to the validity of his method of calculation consists in the obvious fact that it is not yet possible to secure even an approximate idea as to the secular variation of the land area in size. The age of the ocean would be greatly increased if account be taken of a relatively small land area throughout much of pre-Cambrian time. To the present writer Joly’s estimate is of value in suggesting that the pre-Huronian land area was in reality small. J. Joly, Scientific Transactions, Royal Dublin Society, vol. 7, 1899, p. 23. 158 R. A. DALY—-THE EVOLUTION OF THE LIMESTONES late pre-Cambrian ocean could have received an annual calcium supply which was only a small fraction of the present annual supply. The belief may be founded on a comparison between the analyses of rivers now draining large pre-Cambrian areas with the analyses of rivers draining average terranes of the present continents. Few rivers are more typical of the former class than the Ottawa above Ottawa city. Its thousands of miles of trunk and branch channels are sunk in the largest pre-Cambrian area of the world, and it happens that most or all of the recognized rock types of the pre-Cambrian formations are liberally represented in its drainage basin. Only very small and practically negligible masses of younger rocks occur in the basin above the city of Ottawa. At the request of the writer, Mr F. T. Shutt, chemist to the Dominion Experimental Farms, has very kindly made two analyses of the Ottawa water, taken at the Chaudiere falls, which face the city. The first sample was collected on March 12, 1907, at a time when the river was still ice-covered and reported to be at the lowest stage known in fifty years. The second sample was collected on July 16, 1907, during the summer high-water period. Its analysis is more complete than that of the first sample. The two gave results shown in columns 1 and 2 of table II. TABLE II. 1 2, , Low water. High water. | Parts per million. Parts per million. Total solids at 98-100° centigrade.......... 54.66 46.07 LOSS GA MeRI LOM: 27 re en eee 24.03 15.74 Solids-aiter Temition ss... on. es oe ee 30.63 30.33 SEO. g 2surw SS eee ee = 6.52 7.06 AT Oe i 6 ee ae ee ORE ee eee ee ae | 38 52 Hes Ogos cise khan ck See ie ees ee oe | 34 .70 MeO sead gis ac. Rae See She oe ee eee 3.87 2.47 CaO ooo. aks Sot otk ee Se ee eee | 12.57 8.18 INO ec Naas th ine ee Phe Weer a not det. 2.14 ESO seed. Sah eis Sa) 3s ose ae eee not det. : 67 Se een bie lak as <6 che 3s the ee eee 3.70 2.51 Win @iren Wan a: a bis i ere aes oa not det. : 286 TO ee ee ee es Pia ee eee ae not det. 45 CUI eee ete Sel eae coals che ee not det. .50 Five sanitary analyses of the Ottawa river water have been made by Mr Shutt. The samples were taken on the following dates: December 22, 1887; October 18, 1898; December 7, 1898; May 8, 1899, and August 22, 1905. These analyses gave, respectively, total solids at 53.0, 55.6, ANALYSES OF THE OTTAWA RIVER 159 42.4, 48.8, 62.4 parts per million, and solids after ignition (December 22, 1887, not determined), 34.0, 28.0, 22.8, 36.4 parts per milion. The figures average 52.4 parts per million for total solids and 30.3 parts per million for solids after ignition. It will be seen that the variation in each of the two quantities from year to year and from season to season is relatively small; hence we may conclude that the two 1907 analyses fairly represent the average nature of the Ottawa river water in modern times. The content of calcium and magnesiuin of the two stages of the river, and their mean have been calculated to parts per million and the results entered in table III, which also gives, for purposes of comparison, the calcium content of other rivers, as well as of the Ottawa river at Sainte Anne rapids below the solid block of Paleozoic limestones lying between Ottawa and Montreal. The references for the original publications of these latter analyses may be found on page 60 of Bulletin number 330 of the United States Geological Survey. TaBLeE III. River. Terrane. Caleium. sence | Oh ee Parts per | Parts per | Ottawa— million. million. | (GUOWEWIALCY i 252.050 | Late pre-Cambrian..... SCHIST ne ene oEoO ral (D, LELNGe a (200 25 Gree GIG COR Sie ns eter a Meteh en daly Soe cl &, IMIGZI Cen h OKs (eee eee ere rer ae 7.41 2.01 330619) @ Il Cemsare AME... 0... Late pre-Cambrian and 9.92 USO ae OMe al early Paleozoic. | Average of four Swedish | Late pre-Cambrian .....| GaS8o le | LOZ a) Ano2 ll rivers and Ottawa and | | | Pigeon rivers. | | | Saint Lawrence at Ogdens- | Late pre-Cambrian and | 32.05 | 7.21 4.44: 1] burg—average of 6 Paleozoic. | | | monthly analyses. | | | | Mississippi— | a. At Minneapolis—av- | Late pre-Cambrian and | 41.18 | 15.34 | 2.69:1 erage of 23 analyses. early Paleozoic. | | b. Memphis—analyses | Late pre-Cambrian and | 34.38 | 13.75 ZEW col of 17 composites. Paleozoic chiefly. | | c. New Orleans—aver- | Nearly average conti- | 33.90 alOo. | Boy Hal age of 52 composites. nental mass of present | time. | Meammbe—avierage Of 23) |. alias ccesncesweccnsas 43.89 9.94 | 4.42:1 analyses. | imnome—-average of 5.anal- |... 6.6... .0eee ee eee eee 44.91 CP, Why pene ot yses. | nn MEI ae AIR ae ot PEERS a nie 9 coe Sta edlancreta ose O 1389 1.60 | 46.24:1 Average Om omuvers)(Miur= |e... CHEGORS Bi eetete core | 33.85 7.75 Anon wl ray). | Average of 44 rivers......|.. ee CIULOW. Ge Tatts Oeeee net 37.17 | 9203 APSE I TSir John Murray: Scottish Geographical Magazine, vol. 3, 1887, p. 65. 160 R. A. DALY—THE EVOLUTION OF THE LIMESTONES COMPARISON OF THE OTTAWA AND OTHER RIVERS The Ottawa carries past Ottawa city only 23 per cent as much calcium per volume as the Saint Lawrence river carries past Ogdensburg, and less than 20 per cent as much calcium per volume as the Mississippi car- ries past Minneapolis. About one-third of the Saint Lawrence basin is occupied by the Great lakes, in which area probably very little solution of calcium salts is taking place. Another large part of the basin is oceu- pied by the pre-Cambrian terranes where highly calcareous rocks are relatively rare. The content of this river is therefore less than it would be if the river basin were all occupied by the average rocks of the whole continental area of the earth. The comparison of these three rivers is specially instructive, since they are all working under essentially similar climatic conditions, with nearly the same ratio of rainfall to run-off. From the comparison it seems probable that, if the continents were all of their present size and composed of rocks typical of the lands during the late pre-Cambrian, the rivers would deliver to the sea annually not more than one-fifth as much calcium as is carried by the existing rivers of the continents. This conclusion becomes more convincing when the Ottawa water is compared with the other rivers noted in table ILI. In Clarke’s admirable cimpilation of river analyses, those referring to rivers which drain pre-Cambrian terranes throughout their respective basins are five in number, including the Pigeon river of Minnesota and four rivers in Sweden. The average content of calcium (and of mag- nesium) in these rivers, together with the Ottawa at Ottawa city, is stated in the table. It will be seen that the proportion of calcium is very close to that in the Ottawa alone. We have, therefore, corroboration for the view that the Ottawa is a good world type of rivers draining late pre- Cambrian terranes. On the other hand, the Mississippi at New Orleans must be regarded as one of the best types of rivers draining the average terranes of the present continents. From Murray’s average of nineteen rivers the pres- ent writer has calculated the proportions of calcium (and magnesium) and has also (using Clarke’s compilation) calculated the contents of these elements in forty-four of the largest rivers of the globe. In this second computation the individual analyses were roughly weighted according to the areas of the respective river basins. The result is believed to give a~ truer idea of the average content of calcium in the world’s rivers than does Murray’s estimate. / The results seem to show that the average world river, working on the COMPARISON OF THE OTTAWA AND OTHER RIVERS 161 average terrane and under average climatic conditions, carries about the same proportion of dissolved calcium as the average water of the Saint Lawrence at Ogdensburg and the Mississippi above Minneapolis. The table indicates that the influence of the terrane is dominant and the in- fluence of climate subordinate, in their respective controls over the con- tent of calcium. The Mississippi above Memphis drains rock formations which together make fairly good equivalents of the average Mesozoic and Cenozoic land areas. So far as the influence of the average world terranes is concerned, the Mesozoic and Cenozoic rivers were enriched in calcium about as much as the existing world rivers. The early Paleozoic rivers were, on the average, probably not much richer in calcium than the late pre- Cambrian rivers. ‘The control of the Paleozoic terranes on the calcium content of the Ottawa itself is shown by the contrast between the Ottawa city analyses and that at Sainte Anne near Montreal. Even a few hun- dred square miles of upper Cambrian and Ordovician rocks (largely lime- stones) below Ottawa city makes the calcium content materially rise. CHEMICAL CONTRAST OF PRE-CAMBRIAN AND LATER RIVER SYSTEMS In spite of the complexity of the whole problem, we may fairly con- clude that if, in the late pre-Cambrian time, the land areas were of their present size, the ocean then received annually only a small proportion— probably less than one-fifth—of the calcium supphed each year by the present rivers. A contrast of the same order must have existed between the calcium content of the late pre-Cambrian rivers and the rivers char- acterizing most of Mesozoic and Cenozoic time. If the late pre-Cambrian lands had a total area but one-half as great as the present total land area, the rivers may have carried annually to the sea less than 10 per cent of the amount of calcium now carried to the sea by the world’s rivers. This estimate obviously involves the assumption that the pre-Cambrian rate of chemical denudation was no more rapid than the present rate. Since the rate is controlled (apart from the influence of the terrane) principally by the abundance of the organic acids attacking the bedrock, we may well suppose that the well vegetated Ottawa river basin is wit- nessing solution at as rapid a rate as in late pre-Cambrian time. It might be considered that a tropical temperature during the pre-Cambrian would have caused specially rapid solution of the rocks at that time. This view is, however, hardly supported by an inspection of the data relating to existing tropical and extra-tropical rivers. Furthermore, the recent 162 R. A. DALY—-THE EVOLUTION OF THE LIMESTONES glaciation of the Ottawa basin has caused the removal of secularly weath- ered rock, so that the formations now exposed to erosion contain nearly their original amount of soluble matter. For this reason the calcium content of the existing river may be near its possible maximum for a region of average rainfall. Without further entering upon this confessedly obscure subject, we may retain the foregoing estimate as indicating the order of magnitude in the contrast between the late pre-Cambrian and present supply of cal- cium to the ocean through weathering and river inflow. VARIATIONS IN THE CALCIUM SUPPLY DURING AND AFTER THE PRE- CAMBRIAN Before the post-Huronian revolution the supply of river-borne calcium to the ocean was almost certainly less than one-fifth as rapid as it is today, and it may have been less than one-twentieth as rapid, while the amount of animal matter completely decaying each year on the sea-floor, and therewith the likelihood of the precipitation of calcium salts, may have been, respectively, thousands of times greater than they are now. Immediately after the post-Huronian revolution and during the im- mensely long period of baseleveling which followed it, the annual supply of calcium to the ocean may have approached rivalry with the present annual supply. ‘The supply doubtless diminished somewhat as more and more of the Huronian and pre-Huronian limestone and basaltic areas were lessened by erosion and as the Laurentian granite batholiths were uncovered and exposed to solution; but this change must have been very slow, and it did not annul the critical effect of continental enlargement. During the long erosion cycle the ocean was, for the first time, specially enriched in river-borne calcium salts. THE FIRST CALCAREOUS FOSSILS This special influx of calcium salts may be conceived as keeping the surface layers of the sea-water sufficiently supplied with calcium for the needs of lime-secreting organisms, while the bottom layers lost their cal- cium content by precipitation of the carbonate of calcium. Such con- trast of surface and bottom water would be due to the slowness of dif- fusion through a body of liquid so great as the ocean. Under the con- ceived conditions the most favorable places for the invention of calcareous hard parts would be, possibly, localized areas, such as the open sea oppo- site the greater river deltas, or such as the epicontinental seas more or less isolated during the orogenic revolution. The slow spread of the scaveng- FIRST CALCAREOUS FOSSILS 163 ing system may already have had some effect in the late pre-Cambrian, thus increasing the chances that some calcium could remain in the oceanic solution. Since lower Cambrian time the continents have in part undergone sub- mergence and emergence, but they have doubtless never resumed their small total area characteristic of the pre-Huronian period. In any case we have obvious proofs that the ocean has, since the Cambrian, contained enough calcium for the needs of lime-secreting organisms, and the natural explanation is to be found in river inflow. ORIGIN OF THE PRE-CAMBRIAN AND EARLY PALEOZOIG LIMESTONES AND DOLOMITES The hypothesis that the pre-Cambrian sea was nearly limeless involves the corollary that magnesium as well as calcium must have been precipi- tated from the sea-water. The precipitated salt may have been the hydrous carbonate of magnesium, which then united with the calcium carbonate to form dolomite; or crystals of dolomite may have grown at or near the surface of the bottom mud in much the same way as they are erowing today in the buried (porous) strata of the Funafuti atoll.§ The chemical grounds for this belief were partially discussed in the writer’s first paper.° It was there pointed out that ammonium carbonate 1s, under the conditions of the open-sea floor, almost or quite powerless to precipitate magnesium carbonate from the oceanic solution unless all calcium salts have been removed from the solution. In the absence of calcium salts, magnesium can slowly but surely be precipitated by the alkali. We should therefore expect that the formation of magnesium limestones would continue in the ocean until the general scavenging sys- tem was established, thus largely inhibiting the action of the powerful organic alkali. On this view the average pre-Cambrian limestone should show a ratio of calcium to magnesium which is close to their ratio in the average pre-Cambrian river. A similar ratio should characterize those Paleozoic limestones that were formed before the establishment of the general scavenging system. After that system was established, magnesium would begin to accumulate in the ocean. AVERAGE RATIO OF CALCIUM To MAGNESIUM IN THE LIMESTONES OF THE DIFFERENT PERIODS The writer has attempted to test these conclusions quantitatively. For this purpose nearly 900 analyses of types of pre-Cambrian, Paleozoic, § The atoll of Funafuti: London, 1904, pp. 392, 413, ete. ® American Journal of Science, vol. 23, 1907, p. 104. 164 R. A. DALY—THE EVOLUTION OF THE LIMESTONES Cretaceous, Tertiary, and Quaternary-Recent limestones have been calcu- lated, so as to show the average ratio of calcium to magnesium through- out the series. The analyses were taken from the government survey reports of Canada and the United States; from Logan’s “Geology of Can- ada”; from the state survey reports of Arkansas, Indiana, Iowa, Ken- tucky, Minnesota, Ohio, Pennsylvania, West Virginia, and Wisconsin; from the reports of the Ontario Bureau of Mines; from Firket’s elaborate paper on the limestones of Belgium,’® and from the list of analyses sup- plied for the report on the geology of the Cordillera at the forty-ninth parallel of latitude. The selection is far from being as complete as it might be made, but it is believed that enough analyses are represented to give a fairly accurate idea of the variation of the ratio through geologic time. The number of pre-Cambrian and Cambrian limestones averaged is, in both cases, low, but includes nearly all that seemed to be available. The number of the Tertiary and later limestones averaged is again low, but the labor of searching for additional ones did not seem necessary, since it is well known that these later limestones are usually very low in magnesium. Lesley had already prepared a remarkable series of analyses (230) which was intended to afford the average ratio for the Ordovician limestones of Pennsylvania. ‘This result could not, however, be safely used, inasmuch as the whole series refers only to some 370 feet of beds out of several thousand feet of the limestones locally developed, and at that represents only a local phase of the Ordovician."* It has thus seemed better to use the analyses derived from many Ordovician formations in Canada and the United States. The ratio for the pre-Cambrian may be a little too high, for the reason that thirty-three out of the sixty-one analyses selected were taken from Miller’s Bureau of Mines report on the limestones of Ontario, in which there was some tendency to select limestones specially adapted to lime burning. Excluding twelve analyses of specimens from limekiln quarries in Ontario, the average ratio for the remaining pre-Cambrian rocks is 3.61: 1. The results of the compilation and calculation are given in table LV. 10 A, Firket: Annales Société Géologique de Belgique, vol. 11, 1883, p. 221. 11J. P. Lesley: Final Report of Pennsylvania Survey, vol. 1, 1892, p. 327. AVERAGE RATIO OF CA TO MG IN DIFFERENT PERIODS 165 TABLE LV. - : : D. | 3. Buenos | | Ratio of¢CacO: Ratio of aes analyses | “to MgGOs || Ca to Mg. Pre-Cambrian— a. From North America, except those in } 28 1.64:1 2.30): 1 Paro, Ontario (Miller) -.....5.::-... | 33 4.92 :1 6.89 : 1 Pepenverice Of Gand Do... 2.6... eee | 61 sofas ge Jk 4.10: 1 Weesestoeneral average... .. 5. s- 49 2.58 21 BxOleal Cambrian (including 17 of the Shenan- | erAMMmlnNAeSHONE). 20.2.5... ete cee a eee | 30 Zor Men meal a ~ TRG! ONPG 2D Tl a ala | 93 eZee Gleokn sO cark ° SIS, 726 Oe e208 00s ta | 2.08 AUOKre DEVONIAN 2... wee ee we eee ao2 Zags) & 1k Bao) S| EV OLIN De 5 ae ce eee 106 AAO Eat Wwe (O32 020 PEMA MOMMMCTOUS: 2 ccs cis aces evs sles bee nenees 238 Seis) 1) Sa Aor 1S BEIO SCS gy ue Ee eee ae hh AQIS) Fas 32a | ESSE: 22 See eee 26 I esas Ti 53.09 : 1 Airarctnary and Recent. ...............-. 26 2a L007 1 39.00 : 1 Ps). 2 2 18. Be eee 865 | It will be observed that the ratio of calcium to magnesium is fairly constant for all the (392) pre-Devonian analyses, in which the average is 3.35:1.12 The ratio abruptly rises in the Devonian and increases rapidly in the Carboniferous. The Cretaceous shows an apparent maximum, but it is quite possible that a larger number of analyses of Tertiary and later formations would give average ratios at least as high as that of the Cre- taceous.** The ratio for the:pre-Cambrian limestones (3.61: 1 to 4.10:1), like that of all the pre-Devonian, is significantly close to the ratio of calcium to magnesium in the rivers now draining pre-Cambrian terranes, as may be seen, for example, in the Ottawa river analyses made at the capital (low-water stage, 3.82:1; high-water stage, 3.50:1; their average, 3.69:1). -This comparison of itself suggests that during the pre- Devonian time the river-borne magnesium and calcium were wholly pre- cipitated after diffusing to the sea-bottom. In fact, the correspondence must be regarded as giving powerful support to the hypothesis. The abrupt change in passing from the Silurian to the Devonian may, 12Q0n account of the difficulty of finding enough analyses stated for the rocks of the other continents, the comparison of the limestones has been largely confined to the North American formations. An incomplete, preliminary study seems, however, to show that there has been a parallel succession of chemical types among the limestones of the other continents. 13 Cf. C. R. Van Hise: Treatise on metamorphism, 1904, p. 801, and Chamberlin and Salisbury : Geology, vol. 1, 1904, pp. 360, 404. 166 R. A. DALY—THE EVOLUTION OF THE LIMESTONES perhaps, be referred to the development of the fishes during the early Devonian. ‘This development doubtless began in relatively shallow water, and the flesh-eating and scavenging fishes must have aided greatly in preventing the decay of animal matter on the bottom of the extensive Devonian epicontinental seas. During the Carboniferous, and yet more wholesale Permian and-post-Permian emergence, the fishes were driven out into deeper water, where they continued the gradual colonization of the entire sea-floor. So far as the fishes are concerned, that colonization may have been complete in Cretaceous time.‘* That, at any rate, it was complete probably several million years ago seems evident from the chem- istry of the present ocean. According to Murray, the calcium sulphate now dissolved in the ocean could be introduced by existing rivers in about 600,000 years. Since the sulphate is being rapidly decomposed by hme- secreting organisms and converted into deposited carbonate, it is probable that much more than 600,000 years have elapsed since the bathybial fishes and other scavengers colonized the general sea-floor to depths of 2,500 fathoms. The test case of the Black sea shows that the present content of calcium sulphate in ocean water would be largely and rapidly diminished if the scavenging system were not now at work in the ocean. The ratio of calcium to magnesium in the Ottawa river, the best avail- able type of rivers draining the average pre-Cambrian terrane, is 3.69: 1. The ratio for the Saint Lawrence, which is not far from representing a type of the rivers which might drain the average late Paleozoic terrane, is 4.44:1. The ratio for the Mississippi at Memphis, similarly a fair type of river draining average Triassic, Jurassic, or Cretaceous terranes, is 2.50:1. The ratio for the Mississippi at New Orleans, a chemical world type for the present time, is 3.92:1. The’ ratio for forty-four existing rivers is 4.18:1.1° It appears, therefore, highly probable that the ratio of calcium to magnesium for the world’s entire river system has been fairly constant from the pre-Cambrian to the present. We have seen that this ratio is almost identical with that in the average pre- Devonian limestone, but is much lower than the ratio for the Devonian 144This speculation regarding the migration of the fishes into bathybial and abyssal depths is little better than a guess, but it is stated partly to render the hypothesis somewhat more concrete and therefore more intelligible. Meager as are the relevant facts concerning the fishes, those bearing on the Paleozoic and Mesozoic history of the bathybial and abyssal crustaceans, echinoderms, worms, and other scavenging species are almost nil. The profound mystery covering this subject does not, however, affect the general hypothesis favoring a nearly limeless ocean in pre-Cambrian time; for it is next to certain that the more efficient scavengers of the sea-floor, being all relatively high types, were not abundantly developed in Cambrian and pre-Cambrian time. 16 So far as this ratio is concerned, a single analysis of a river may have high value in the discussion, since Dubois has shown that, no matter how much the absolute amounts of solute in a river may vary throughout the year, the proportions of the dif- ferent salts remain nearly unchanged (KE. Dubois, op. cit., p. 48). SUMMARY ON ORIGIN OF PRE-DEVONIAN LIMESTONES Ow and post-Devonian limestones. Granting that the calcium and magne- sium in sea-water have been introduced by the rivers, the sudden increase of the ratio Ca: Mg in the Devonian limestones must mean that during the Devonian the magnesium began to accumulate in the oceanic solution with special and unprecedented rapidity. On the hypothesis that the ~ycean was nearly limeless in pre-Cambrian time and very low in lime during early Paleozoic time, it follows that only a minute amount of mag- nesium could have remained in the oceanic solution during pre-Devonian time. Since the period of the general colonization of the sea-floor, the pre-- cipitation of magnesium carbonate direct from sea-water has been possible only under special conditions, so that the more recent time has seen the minimum formation of magnesian deposits. SUMMARY ON THE ORIGIN OF THE PRE-DEVONIAN LIMESTONES The close correspondence of the ratio Ca: Mg in the pre-Devonian limestones with the ratio Ca: Mg in such type rivers as the Ottawa, Saint Lawrence, and Mississippi, as well as with the average river, can hardly be accidental. ‘The readiest explanation of this correspondence seems to be found in the view that all the pre-Devonian river-borne calcium and magnesium were precipitated on the sea-floor. The ultimate products are dolomites and magnesian limestones as well as more purely calcareous hmestones. The causes for the variability of their composition are briefly discussed on pages 107-108 of the first paper. In cases where the magnesian lhmestones are of pre-Cambrian age they are, in general, to be regarded as precipitates on the floor of the open ocean and not as formed in closed basins subject to intense evaporation. A study of the tables of rock and river analyses has led the writer to ascribe a similar origin to the staple pre-Devonian carbonate rocks as well as to many limestones and dolomites of still later date. TESTIMONY OF THE GRAIN OF THE PRE-ORDOVICIAN LIMESTONES It may be added that a close study of the grain of unmetamorphosed Cambrian and pre-Cambrian carbonate rocks has convinced the writer that they are not of clastic origin nor of direct organic origin through the accumulation of shells or skeletons. More than 7,000 feet of such rocks are exposed in the Forty-ninth Parallel section of the Rocky Moun- tain geosynclinal prism. Type specimens of these have been examined microscopically. It was found that neither horizon nor distance from the old shorelines affects the singularly monotonous grain of the rocks. 168 R. A. DALY—THE EVOLUTION OF THE LIMESTONES The constituent particles are either idiomorphic and roughly rhombo- hedral, or anhedral and faintly interlocking. The former are everywhere of nearly uniform average diameter, ranging from .01 millimeter to .03 millimeter, with an average of about .02 millimeter. The anhedral grains range from .005 millimeter to .03 millimeter, averaging about .015 milli- meter in diameter. The same uniform grain was found in the Archean (pre-Belt terrane) dolomites (where unmetamorphosed) at the headwaters of Priest river, Idaho; in the magnesian limestones and dolomites inclosing the pre- ‘Cambrian chitinous fossil, Beltina dana, in the Clarke (Livingston) range; and in the Siyeh and Sheppard siliceous limestones of northwestern Montana, which appear to be of Middle Cambrian age. In his account of the Norwegian marbles, Vogt states that the rocks of finest grain are -made up of granules averaging .02 millimeter to .03 millimeter in diam- eter, and he distinctly states that the Norwegian dolomites are direct chemical precipitates. | Again, it is important to note that the average diameters of the car- bonate granules are of the same order as the average diameters of calcite and dolomite crystals, which are unquestionably due to chemical precipi- tation from sea-water or saline solutions at ordinary temperatures. Cullis has shown that the calcite granules deposited from sea-water in the cavi- ties of the Funafuti corals have average diameters of from 0.02 to 0.03 millimeter ; also that the dolomite crystals, which have gradually replaced the aragonite and calcite of the coral deposits, are of similar size.1* When solutions of calcium chloride and alkaline (sodium) carbonate react at ordinary temperatures, crystals of calcium carbonate are slowly formed, which reach the same dimensions.‘* The granules constituting the “eggs” of the Belt-Cambrian oolites likewise average 0.01 millimeter to 0.02 millimeter in diameter; the eggs are clearly chemical, inorganic growths. Finally, it may be noted that a specimen of the Black sea chemically precipitated (teste Andrussow), calcareous mud, when micro- scopically examined by the writer, showed granules of similar range of magnitude. GENERAL CONCLUSION Notwithstanding the many uncertainties and difficulties of the case, it seems justifiable to use the Ottawa river and other analyses in an attempt to evaluate the great chemical difference between the average river water iJ. H. L. Vogt: Zeitschrift ftir Praktische Geologie, January and February, 1898. 70. G. Cullis: The atoll of Funafuti, London, 1904, p. 392; see text figures and plate F. 18H. B. Stocks: Quarterly Journal of the Geological Society, vol. 58, 1902, p. 54, BP pc: GENERAL CONCLUSION 169 of the pre-Cambrian and that of the present time. The comparison strengthens the hypothesis that the ocean during an immense part of pre- Cambrian time was chemically unfit for the secretion of calcareous tests and skeletons. The pre-Cambrian fauna is thus regarded as largely a ‘Sellyfish” fauna, although siliceous and chitinous fossils may be looked for in pre-Cambrian rocks. The ratio of calcium to magnesium in the rivers draining the pre- Cambrian terrane is almost identical with the ratio of calcium to mag- nesium in the average pre-Cambrian and pre-Devonian limestones. Nearly all of these limestones are credited to chemical precipitation, which steadily removed both calcium and magnesium from the pre- Cambrian ocean as fast as those elements were introduced by the rivers. The chemical reaction, which was largely or wholly responsible for the precipitation of the carbonate rocks, is also the reaction considered as responsible for the nearly limeless state of the pre-Cambrian ocean. Be- cause the ancient dolomites and limestones were deposited, that ocean was nearly limeless; in this conception there is neither paradox nor incon- sistency. ‘The actual content of calcium in the pre-Cambrian ocean was at any moment extremely small, as the dilute solution of river-borne salts diffused to the bottom; to the pre-Cambrian organisms the ocean was practically limeless.?® In late pre-Cambrian time the deposition of the carbonates may have been no more than one-tenth as rapid as the deposition of the carbonates now forming, through all causes, beneath the sea. Immediately after the orogenic revolution of the somewhat earlier pre-Cambrian (post-Huro- nian), the deposition must have been at a maximum rate, though that rate may not have reached the one now prevailing. In any case, estimates of the earth’s age, when derived from the rate and amount of past sedi- mentation, should take account of secular variations in the supply of river-borne salts to the ocean. It is suggested from the facts noted in this paper that the magnesium now contained in the sea in amount greater than a mere trace began to 19 As a result of his remarkable researches on the waters found in the deeper mines of the Lake Superior region, Lane has concluded that these are ‘‘connate’”’ waters—that is, waters which were trapped and buried in the sediments and lava-flows formed on the pre-Cambrian sea-floor (A. C. Lane’s paper, read at the thirteenth annual meeting of the Lake Superior Mining Institute, June, 1908). It may be a good working hypoth- esis to consider the extraordinarily high content of chlorine in the many analyses as of connate origin, but the likewise abundant calcium present can be explained as due to solution along the walls of the ancient pores and fissures. To put it briefly, some ele- ments of the mine waters may be connate and of marine derivation, but such original water must have been chemically changed by metasomatic interchange with the in- closing (always lime-bearing) rocks during the post-Cambrian period. Mine waters from pre-Cambrian terranes can not, therefore, in the writer’s view, afford safe indica- tions as to the calcium content of the pre-Cambrian ocean. XIII—Butu. Grou. Soc, AM,, You, 20, 1908 170 R. A. DALY—THE EVOLUTION OF THE LIMESTONES accumulate not earlier than the Devonian period. The calcium did not begin to accumulate in similar excess until the general scavenging system was established in the “bathybial” (not “abyssal”’) regions of the ocean floor—perhaps as late as the Cretaceous period. When we also bear in mind that the sodium and potassium salts have been slowly accumulating from the pre-Cambrian to the present time, we are prepared to reach the rather probable conclusion that the pre-Cambrian ocean really approx- imated a fresh-water (though, perhaps, faintly acid) condition. The only escape from that conclusion seems to be offered in the view that a large part of the existing ocean is made of nearly pure “juvenile” water emitted from volcanic vents or from primary igneous rocks since the pre- Cambrian. The actual calculation of about 900 typical analyses confirms the pre- vailing view that the Paleozoic and pre-Paleozoic limestones are more highly magnesian than the more recent limestones. The ratio of calcium to magnesium is nearly constant in the average limestones of the pre- Cambrian, Cambrian, Ordovician, and Silurian formations. That ratio rises abruptly in the average Devonian limestone and increases again greatly in the average Carboniferous limestone. In the Cretaceous lime- stones it reaches a maximum value which is very close to, or sensibly equal to, that characteristic of the average Tertiary and Recent lime- stones. Detailed field work and microscopic and chemical study have indicated that the higher proportions of magnesium in the older limestones can not be explained by their having been more deeply buried and more meta- morphosed than the younger limestones. The evidence shows that the magnesian content of the staple pre-Devonian limestone is original, in the sense that the magnesium carbonate was precipitated from sea-water. In many, if not all, cases the dolomite crystals may have been formed at or near the surface of the ancient calcareous muds by the interaction of the magnesian salts of the sea-water with the more easily precipitated calcium carbonate. Porosity of the sea bottom would aid this process, as it is today favoring the dolomitization of certain more porous beds in the Funafuti atoll. In brief, the chemical composition of the ocean water, the conditions of life in the sea, and the marine limestones in general have all had a correlative evolution. The hypothesis founded on this central thought is at many points in this paper strongly charged with speculation; each item of speculation is offered not only as a means of intelligently group- ing the many facts relating to this important theme, but also, and more especially, as an advertisement calling for new facts. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL 20 PP 1v1-196)) May 5, 1909 GEOMETRY OF FAULTS? BY HARRY FIELDING REID (Presented before the Society December 29, 1908) CONTENTS Page ame ee ANIA AMP ep ah ihe tha ys ch pet oes ales oe Tes Seth seotar's: Reiia ahat ae duh nea oe ore eile, aleGava\'e) aiearve Arid © GTS ISVTEITEYS yh ga anne ak oo en a a ee nee Sn en ee a a ee G2, Seer CRIED FUP) UTOM arte tals: seyty cus re) ‘ UN ‘ 4 e re | ‘ | | Vee ; A Orse| : a er ; | hi on , NS ; fi \ ‘ | 1 . dL - 4 i oil om ' ‘ ie el ; Sar er Pl < ' 4 2 \ ' i : \ LU ‘\ . < i re tyke Bh AF ig ! 5 oetles cag 3 ' uw 7 (eee r See Dyke 1 \ ub ‘7 te W P| FiIcuRE 8.—Determination of the Shift, Case Il fgi¥ fg is the depth of the original of f; hence giv gi! is the total amount of the shift and fkg'¥ is its inclination. The actual movement is known and all displacements can be immediately found. In this case the point of the stratum, 7’, at the original of f before disruption, moved PARALLEL DISPLACEMENTS 183 up the fault-plane to the original of f’, or a point of the stratum, ¢, has moved in the opposite direction. The horizontal line at right angles to the fault-trace has therefore been shortened by the amount equal to /f”, the horizontal projection of the line ff’, at right angles to the fault-trace. If the stratum and the two dikes meet on the undisturbed side of the fault, they will not meet again on the displaced side; but their virtual meeting point can be determined by finding the meeting point of the three displaced planes produced. Case II: Given, the traces, dips, and offsets of a stratum and of two dikes. Suppose we have not found the fault itself, but have found the traces of the disrupted stratum, 7’, ¢, figure 8, and have also found the parts of two dikes which have been disrupted by the fault. We proceed as in the former case; we find the projection, f, of the meeting point of the stratum and the two dikes before the disruption, and the projection f’ of the point where their displaced parts meet. The line ff’ will be the projection of the total shift; fg and f’ g’ will be the depths of the orig- inals of f and f’ respectively; gg’ will be the total amount of the shift, and 8 will be its inclination; f” f’ will be the lengthening of a horizontal line at right angles to the fault-trace. Although we have determined the direction, inclination, and amount of the total shift, we have not determined the fault-plane, for there are evidently an indefinite number of planes which can contain a line par- allel with the original of ff’. If we have found one point of the fault- plane where, let us say, dike 1 has been disrupted, we can still pass an in- definite number of planes through that point which would contain a line parallel with the original of ff’, but if we have also found a second point where, for instance, the stratum has been disrupted, the fault-plane can be immediately determined. We shall suppose these two points to be the originals of a and 0, and that they are not in the horizontal plane, but, on account of the topography, the original of a lies above, and that of b below, this plane. The altitudes of the originals of a and 6 would naturally be determined in the field; but, since one lies on dike 1 and the other on the stratum, we can find the altitude each must have by the ordinary method of the dip-triangle. We thus find that the original of a lies a distance ae above the horizontal plane, and that of b at a distance bd below it. The fault-plane must pass through the original of ab and contain a line parallel with the original: of ff’; therefore it must contain a line through the original of a parallel with the original of ff’; ah will be the projection of this line. The trace of the fault-plane must pass through the points & and c, where the originals of ah and ab intersect the reference plane. Moreover, the fault-plane contains the original of 184 H. F. REID—-GEOMETRY OF FAULTS b, whose depth is bd; and a contour on the fault-plane through the orig- inal of 6 must have the depth bd; therefore lay off bd’ bd through 6 and parallel with the fault-trace, complete the dip-triangle, and 8” will be the angle of the fault-dip. At the time of the rupture the stratum, the projection of whose intersection with the fault-plane is /m, slipped diagonally down the fault-plane in a direction parallel with the original of ff’ and at an angle less steep than that of the original of /m. A hori- zontal line at right angles to the fault-trace was lengthened by an amount, f” f’, but the intersection of the displaced stratum with the fault-plane (original of /’ m’) will be above the intersection of the fault- plane and the undisturbed stratum (original of /m), and the fault would therefore be called a reversed fault. | Case III: Fault in igneous rock. Given the trace and dip of the fault- plane; the traces, offsets, and dips of two dikes, or of one dike and an old fault-plane, or of any two planes which have been disrupted by the fault. The construction in this case is exactly like that in case I. Case IV: Gwen, the azimuth and inclination of strie, and the traces, offsets, and dip of a stratum, or of any plane disrupted by the fault. Let 7’, t’, figure 9, be the traces of the stratum; jf’ the projection, and 8’ the inclination of the strie, the original of / being the lower point. Let us find the total dis- placement of some point, d, on the trace ae Through d pass a line par- allel with the striz; dd’, parallel with /f’, will be its projection; pass a plane through d, having Td for its trace and containing the original of the line dd’; its dip will be 8”, ob- tained by the method given on page 175. This plane will meet the dis- placed stratum, ¢’, in the contour h’ e’, obtained by laying off the dip 6 at c', as shown in the figure, and finding the intersection, e’, of the lines de’ and c’ e’; and therefore the original of line dd’ will meet the plane in the same contour in the original of the point d’. dd’ will therefore be the projection of the shift of d, and dg’ obtained by laying off the angle 8’ at d, or by drawing d’ g’ equal to h’ e’, will be its amount. Figure 9.—Determination of the Shift, Case IV PARALLEL DEVELOPMENTS | 185 We have not fixed the fault-plane, but if the direction of the strice have been determined it is probable that the strike and dip of the fault- plane have been also. If they have, we can determine the projections of the lines of intersection of the fault-plane and the stratum, as in case I and figure 7; then draw a line parallel with the azimuth of the stric connecting the two lines mentioned; the depths of the two ends of its original can be found, and thus its dip and the total shift. If one side of the fault should be igneous and the other side stratified rocks, we can in general infer which side has been relatively raised, and FIGuRE 10.—Determination of the Displacement of a Plane, Case V we may be able to estimate the vertical throw from the thickness of the stratified rocks; but if the fault is diagonal with respect to the strata, a further complication is introduced. By following along the fault we -may come to a place where the strata are horizontal; it is also possible that traces of the stratified rock, which have not been entirely eroded off, .may be found on the igneous rocks, which would indicate the vertical throw and the horizontal shift; but we could not, without finding the hade of the fault, determine whether the fault were normal or reversed. This, however, is rather a case of folded than of plane strata. 186 H. F. REID—GEOMETRY OF FAULTS Not infrequently the strata on one or both sides of the fault-plane have been bent up in a direction opposite to their displacements. In finding the displacements we must use the position of the strata outside this distorted portion; the shift thus determined refers to the relative displacement of the rock in general on opposite sides of the fault and not to the actual slip on the fault-plane, which may be somewhat less. Case V: Given, the total shift, in amount, direction, and inclination; to determine the displacement of any plane, such as a stratum or vein. Let ff’, figure 10, be the projection of the shift, its inclination being 98, and f’ being the projection of the higher point; the difference of level of these two ends of the shift is fg. Suppose a plane is given by its trace, T, and by its dip, 8. A point of this trace, which was originally at d, has been moved to the original of d’, a distance equal to and parallel with the original of ff’, the height of the original of d’ above d equals fg. The displaced part of the stratum passes through the original of d’ and dips to the north at an angle 6. It will reach the horizontal plane at a point, 7’, found by drawing d’ 7” at right angles to the trace T,, and erecting d’ g’==fg at right angles to d’ T’, and at g’ laying off the angle 90° —68; g’ T’ meets d’ T” on the trace of the displaced plane; for if the triangle d’ g’ T’ be rotated about d’ T’ until g’ is vertically above 7’, the line g’ T’ will lie in the dip of the displaced plane and will cut the horizontal plane at 7’. The trace, 7’, can then be drawn parallel with T. If the trace, F’, of the fault is given, we can find the fault-dip, 8”, and consequently the projections he and h’e’ of the fault intersections with the strata T and T’; the stratum 7 will not extend to the right of he, nor T”’ to the left of h’ e’. FOLDED OR CONTORTED STRATA The changes in the shape of the strata prevent us in this case from using the very simple construction given above, and if the fault should be a strike-fault it is in general necessary to make a pretty complete geo- logical section in order to compare the two sides and determine the move- ment which has taken place at right angles to the fault-strike. The movement parallel with the fault-strike would have to be determined as in the former case, by the dislocation of a dike or of some other plane. In the case of diagonal or dip-faults our problem is somewhat easier. The crest of an anticline or the trough of a syncline furnishes a line which has been dislocated by the fault, equivalent, in our former case, to ROTATORY DISPLACEMENTS 187 the intersection of two dikes, so that we can immediately say that a point of this line on one side of the fault has been displaced to a point of the displaced line on the opposite side of the fault. If we can determine the strike and dip of the fault-plane, the whole movement can be determined. This can also be done if we can find the strike, dip, and offset of a dike or other broken plane. RotTatTory DISPLACEMENTS SIMPLE ROTATION WITHOUT TRANSLATION In this case the fault surface will be a surface of revolution, with the axis of rotation as its axis of revolution; it is only under these conditions that the movement can take place and contact be maintained between the two sides. The axis is apt either to be at right angles to the fault sur- face or not actually to intersect it at all; for if it should intersect the fault surface in an acute angle, the surface must, in the neighborhood of the point of intersection, envelop the axis like a cone—a form which has never been observed. Professor Jaggar has suggested that some faults occur in which one side has rotated as a block about an axis at right angles to the fault- plane.» I am not sure that movements of this kind occur on a large scale in nature; certainly the California earthquake fault, which Pro- fessor Jaggar refers to, is not an instance of it; and it is difficult to understand what allowable forces would cause such a rotation. We must remember that the continuity of the rock must exist except at the actual break, and that the displacement of faults is taken up near their ends by plastic or elastic distortion. Moreover, in very large masses the rock ean not be expected to act like a rigid body. If the angle of rotation is small, we can decide if the main part of the rock rotates about a single axis by determining the displacement at different parts of the fault by methods already given; then by a comparison of these displacements we can see if they all represent a rotation around the same axis. If they do, the directions of the movements must be all at right angles to the radii drawn from a single axis, and the amounts at different points must be proportional to the distances of the points from the axis. The axis can then be easily determined, as pointed out by Professor Jaggar, by finding the intersection of lines drawn at right angles to the directions of the movements. If the angle of rotation is large, we have merely to deter- 5“HBconomic geology,” 1907, vol. ii, p. 60. XV—BULL. GEOL. Soc, AM., Vou. 20, 1908 188 H. F. REID—-GEOMETRY OF FAULTS mine the rotations of lines in the plane of rotation, and see if these rota- tions are equal in different parts of the fault. If the fault surface is nearly plane, its intersections with the strata afford excellent lines for determining the rotations. Small rotations, of limited extension, and with the axes at right angles to the fault surface, apparently occur in all ordinary faults. If we fol- low along a fault we finally come to a point where it dies out, and we find in different parts of its course that the amount of the vertical throw has varied. This, of course, requires a certain amount of bending of the strata, and this bending constitutes a rotation of that part. The rotation is not the same at different parts of the fault’s course, and may even vary in its direction, in which case we should have gentle folds whose axes are at right angles to the fault-strike. The rotation, of course, is greatest where the rate of variation of the vertical throw is greatest, and this is very apt to occur near the ends of the fault. If the strata are nearly horizontal, a slight rotation will make a great difference in the direction of the strike, and thus the strata on opposite sides of the fault will strike at each other. If, however, the strata are highly inclined, the variation in the strike will be extremely small. Where the rotation is small, the error introduced by treating the displacement as a simple translation, without considering the rotation, would be unimportant. Where the rotation is appreciable, it is best to suppose the strata rotated back through an angle until they become parallel on opposite sides of the fault. We can then determine the displacements by the methods already given; and we must add, as a part of the description of the fault, the amount of rotation which has taken place. We must decide by general conditions, such as the relation of the strike and dip of the strata to the same quantities beyond the ends of the fault, whether one or both sides have been rotated. As this is a case of rotation and transla- tion, it might be treated by the method of the next section; but the method just given is simpler and might be preferable, where the main part of the displacement is a translation accompanied by rotations un- evenly distributed in the various parts of the mass. When the axis does not intersect the fault surface, the fault usually occurs only on one side of the axis, and on the other the rocks yield by plastic bending. Movements of this kind apparently take place when large blocks, like the Sierra Nevada mountains, for instance, are tilted up. A section of the fault surface in a vertical plane at right angles to the axis would be circular, but its ground plan might have almost any shape, dependent upon the distribution of the forces causing the move- ROTATORY DISPLACEMENTS 189 ment. We can not look upon such a large mass as acting like a rigid body; there is a certain amount of distortion as the fault dies out near its ends, and the rotation is probably not constant along the fault or at right angles to it, the differences being permitted by small plastic distor- tions. The folded strata of the Sierras would make it impossible to de- termine, by their positions, the variations in the rotation of different parts of the mass; but physiographic methods might yield more definite results. The Wahsatch mountains offer another example of a large tilted block; its western boundary fault must be a surface of revolution. A landslide where the mass holds its form and is not broken is an example of this kind of rotation on a small scale. Another fairly common example of apparent rotation with the axis parallel with the fault surface is the upturning of the edges of the strata on the downthrow side of a fault, which usually extends but a short dis- tance from the fault-plane. This may be due to a general shear, to a large number of minute faults parallel with the main fault, or to the bending up of the individual strata accompanied by a slight slipping of each stratum upon its neighbor, just as cards slip upon each other when a pack is bent. ‘The last method seems to me the one we should expect to occur most frequently. This is not a true rotation of a block as a whole, but is a distortion of the rock-mass, suggesting a rotation on ac- count of the tilting of the strata. It is better to look upon such a quasi- rotation as a disturbance in the neighborhood of the fault and, as already hoted, to make our observations for displacements at a greater distance, beyond the zone of upturning. Where a simple rotation has occurred it is easy to determine its axis and amount, if we know the plane of rotation. Let figure 11 be a section in a plane at right angles to the axis; lea and @’ be the disrupted parts ,,.. -- --. of the same stratum before and after Boy rotation; extend the directions of these parts until they meet in O’; 8 will be the angle of rotation. Erect 9 ,-~ a perpendicular to the middle point “~~ of the line connecting a and a’, and find a point on it at which the line aa’ will subtend the angle 8; this point, O, will be the axis about which the rotation took place. ‘ \ ry « HiGuRE 11.—Simple Rotation ROTATION WITH TRANSLATION Where both rotation and translation have taken place we may either suppose a particular point of the rock to have been moved directly to its 190 H. F. REID—GEOMETRY OF FAULTS new position, and the mass then rotated around an axis through this point, or we may represent the whole displacement as made up of a rota- tion about a properly chosen axis and a translation along that axis; that is, by a movement similar to that of a screw. The fault surface will be a screw-surface, though it may approximate, or even become, a cylinder or a plane; in the latter case the movement will reduce to a simple trans- lation or a simple rotation. It may be a question whether a composite displacement of this kind occurs in nature on a large scale; but, as the oS Figure 12.—Rotation and Translation method of treating this case is the same as that of finding the axis of a simple rotation, when the observations do not make the direction of the latter immediately evident, we shall take up the more general case. This case is perfectly general, and includes every possible displacement of a rigid mass without distortions. It is quite evident that if three points in a body are fixed, the body itself is fixed ; and if the displacements of three points are known, the dis- placement of the body is known. Three points determine a plane and the ROTATORY DISPLACEMENTS 191 directions of lines and the positions of points in the plane. When we wish to determine the rotation which a rock-mass has experienced, we may then determine what rotation is necessary to bring a plane of the - undisturbed mass into parallelism with its displaced position, and what further rotation is necessary to make a line in this plane parallel with its position in the displaced plane. If a translation has also occurred, its amount can easily be determined. Let us take a stratum for the plane, and for the line, the intersection with it of a dike or vein. ‘The intersec- tion of this line by a second dike will determine a point. In figure 12 let TT be the trace of the undisturbed stratum, and 6, its dip; let ¢¢ and 6, be its trace and dip after displacement ; let the original of line he in the first stratum be displaced into the original of bg, and let the original of point f go over into the original of b’; the problem is to find the character and amount of the total displacement. The method is to rotate the plane 77 about its intersection with ¢¢ until the two eoincide, and then to rotate the plane 77’ about an axis perpendicular to it until the originals of the lines fe and bg are parallel; the direction of the axis and the amount of the total rotation can be calculated from these two partial rotations. As TT and tt do not intersect within the limits of the figure, we intro- duce an auxiliary plane, 7” 7”, parallel with TT’, intersecting ¢¢ in the original of 7” xz. The original of ac will be parallel with the original of he, a lying on the trace T” T’. In order to bring the two planes into coinci- dence we must first make the original of 7” a2 horizontal; we therefore rotate the whole mass about ¢f through the angle 8,, and the former line comes into the horizontal plane in 7” 2’; this 1s done as follows: g is the projection of a point on the intersection of the two planes, and also on the original of line bg; draw gk perpendicular to ¢t, and at right angles to this line lay off gg”, the depth of the original of g; with kg” as radius, draw the arc g” g’ intersecting kg in g’; g’ will be the new position of the original of g. TZ” and b, being on the trace ¢¢, are not moved by the rota- tion, and therefore 7” g’ and bg’ are the new positions of the originals of I’ x and bg. Similarly a’ c’ becomes the new projection of the original of ac; a@ goes over into a’, with a’ d’ as the new depth of its original. So far we have rotated the whole mass and have made no changes whatever in the relations of its different parts. We have really merely changed our plane of reference. Now, leaving the plane ¢¢ horizontal, we rotate the plane 7” 7” around 1” x until the two planes coincide. We have seen that the original of a’ on the plane 7” 7” lay at a depth a’ d’, or a’ d” ; and therefore, to raise this 192 H. F. REID—GEOMETRY OF FAULTS point to the horizontal plane, we find it must be rotated through the angle y,, which immediately appears if we consider the triangle a’ id” as verti- eal. When the rotation through the angle ¢, is accomplished the two " " planes coincide, and the original of a’c’ becomes a” c”. On rotating a” c” about a vertical axis through the angle ¢,, it coincides with bq’. We have rotated 7” T’ through an angle ¢, around a horizontal axis T’ 7’, and then around a vertical axis through an angle ¢g,. We can combine these two into a single rotation, just as we can two simple translations. At i lay off a distance towards 7’ proportional to ¢,, and vertically down- ward a distance proportional to ¢,; on completing the parallelogram the diagonal will give the direction of the resultant axis, and its length will be proportional to its amount. In representing a rotation by a length of its axis we measure the length positively in the direction in which the rotation: would carry a right-handed screw. By measuring ¢,=a id’ and ¢,=g' nc’, we find them respectively 15° and 10.3; and ¢ becomes 18.2°; it’ will be the projection of the axis, which will dip down from 1. 7 We must now bring our whole mass to its original position by rotating back through angle 6, about tf. The original of 7 will be brought to the original of e, that of 2’ to that of e’, and the axis of rotation will become the original of ee’ ; its dip, 6, is readily found by laying off, at right angles to ee’, at e, and e’ respectively, the depths of their originals and joining the ends of the lines thus drawn. As this line does not meet ee’ within the limits of the figure, we find 6 by drawing an auxiliary line parallel with it, and which intersects ee’ at a convenient point, p. We have found the direction of the axis of rotation; that is, its projection is ee’, its posi- tive direction is from e towards e’, its dip is 8; its amount is 18.2° ; but its actual position may be anywhere; and if we choose a position for it we can then determine what translation is necessary, in addition, to make the un- disturbed stratum coincide in all respects with its displaced part. In par- ticular we may choose the proper position of the axis in order that the translation shall be along it. For this purpose let T” T” be the trace of a plane at right angles to the axis; its dip will be J = 90° —6. Revolve everything up through the angle, w, about this trace; the axis of rotation (original of ee’) will become vertical and f will go to 7’, and b’ to b”. A point, 0, can now be found on the perpendicular bisector of f’ b” at which f’ b” will subtend the angle of rotation, ¢ ; this then will be the position of the axis, for /’ will be brought to b” by a rotation, ¢, around this point. The original of f’ is at a distance f’ f”, and the original of b” is at a dis- SPECIAL DIFFICULTIES 193 tance b’’ b”’ above the plane, and therefore the translation parallel with the axis consists in raising f’ through the difference of these distances. Rotating everything down around 7” 7” through angle, ¢, to come back to the original position, o goes to the original of 0’, whose depth is 0’ 0” ; and if at o” we draw the line 0” P, making the angle ¥ with o” o’, the point of intersection of 0” P and o’ o will be the point where the axis of rotation intersects the horizontal plane, o o’ will be its projection and its positive direction, 5 will be its dip, and ¢ its amount; b” b”’ —f’ f” will be the translation. If this latter quantity should come out zero, then the whole displacement would be a simple rotation; but in general it would be impossible to assume in the beginning that this condition held. _ We have treated this case as though the strata were plane, but this is not at all necessary. If the fault were diagonal to the strata, we might be able to construct the geological section on opposite sides of the fault, and we could determine the rotation by considering the displacement of a plane tangent to the apex of an anticlinal, and the line of tangency; or if a dike cut the strata, the plane of the dike and a line in this plane tan- gent to the apex of an anticline could be used equally well; the intersec- tion of the dike with the apex of the anticlinal would furnish a point whose displacement would determine the translation. SPECIAL DIFFICULTIES There are two kinds of accidents which may materially interfere with the determination of the actual movement of a fault. The first of these is an unconformity. ‘This may be entirely covered on the downthrow side, so that only the strata above it are exposed, and on the upthrow side all the strata above the unconformity may have been eroded away. The strike of the strata will in general be different on opposite sides of the fault, but this, of course, will have nothing to do with a rotation. We must reconstruct, if possible, the position of the strata below the uncon- formity on the downthrow side; otherwise we can only determine at best a limit to the amount of the vertical throw. The second kind of accident that may interfere with consistent results is due to the fact that the whole movement at a fault may have been made up of a series of steps, and it is quite possible that dikes or veins may have been formed at a time between the steps; their displacement would not then represent the whole movement on the fault. Moreover, it is by no means necessary that the direction of movement of all the steps should 194 H. F. REID—GEOMETRY OF FAULTS be the same, and therefore strie which may be found may only represent the last step, and if their direction were taken as the direction of the whole motion, we should be led to erroneous conclusions. It is diffieult to say just how these various accidents may be avoided; each case must be treated by itself; but in general, if we have more observations than are necessary to determine the movement, we can compare the results ob- tained by combining them in different ways, and if the results are all accordant we may feel pretty sure that we have determined the full moye- ment. For instance, if we have given, not only the offsets of three inde- pendent planes, but also the direction of the striw, we have several methods of determining the total shifts. If they do not give the same results, we may be sure that the offsets of the planes were not wholly due to the movement which produced the strie. POSSIBLE DISPLACEMENTS When faults extend over very long distances they are usually not very straight, and sometimes they curve considerably. The form a fault will take will depend on the strength of the rock along its course and the dis- tribution of the forces which produced it. It is hardly probable that where the curvature is great the displacement could have a strong hori- zontal component; but it might be either a translation or a rotation. In the former case the intersection of the surface with the plane containing the movement would be a straight line; in the latter it would be a circle. If both a translation and a rotation existed in not too unequal propor- tions, it is probable that the fault surface would become nearly a circular cylinder, and its course along the earth’s surface would not be far from straight. These surmises must not be applied too vigorously; it is only in small masses that the rock may be considered rigid, and the displace- ments might be very different in the different parts of a long fault as a result of plastic deformations. Where two faults intersect and neither suffers an offset, we must con- clude that the blocks in the four angles have suffered displacements par- allel with the line of intersection of the two faults. Sometimes the rock is found to be broken up by numerous faults into a series of blocks. If the blocks defined by three or four faults do not have their edges parallel, but are wedge-shaped, we may be sure that the movements on the different faults occurred at different times, and we CONCLUSION 195 should expect the older fault-planes to show offsets; for if the block moves on several fault-planes at once, it must move parallel with their several lines of intersection, which must therefore be parallel with each other. Wedge-shaped blocks are sometimes represented in geological sec- tions bounded by intersecting faults with the movement shown by the displacement of the strata, but with no offset shown on either fault. This is an impossible arrangement. Not infrequently blocks are represented as displaced and tilted in ways which can not, apparently, be accounted for unless some of them have been plastically deformed ; and there is no evident reasons why these par- ticular blocks should have been singled out for such deformations. These matters are mentioned here in order to call attention to the necessity of considering what displacements are possible with blocks which are nearly rigid, when sections must be drawn from incomplete data. CoNCLUSION The varieties of complex faulting are very great, and no attempt has been made to treat them all. The method of treatment has been fully set forth and a number of examples given. The method is so simple that it can be mastered in a very short time; and other cases can then be treated without difficulty. The projections show at a glance the com- plete structure. Where folded strata exist their forms must be indicated by their proper contours. ‘The confusion due to the multiplicity of lines ean be avoided by using different surfaces, by rubbing out construction lines after they have served their purpose, and by drawing separate dia- grams to represent the structure between successive selected levels where, as in the case of mines, the tunnels increase the complexity of the draw- ings. ‘T’o persons unfamiliar with geometrical projections, the method may at first seem difficult to use; but the nature of the problems requires the consideration of space relations, and the method here given is prob- ably the simplest possible method of dealing quantitatively with these relations ; and without quantitative methods we can not get quantitative results. Sometimes the character of the movement on a fault can be inferred from certain general considerations, such as the prevalence of normal or reversed faulting in the region, from the general nature of the forces which have been active, or from a consideration of the general surface XVI—BULL. Grou. Soc. AM., Vou. 20, 1908 196 H. F. REID—GEOMETRY OF FAULTS distribution of the rocks. All of these methods are valuable where more accurate ones can not be used; but it must be remembered that the results represent the judgment of the observer and are not true determinations. Geology is still far from being an exact science, but the effort should be made to introduce accurate methods wherever it is possible. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 197-222 JUNE 5, 1909 ies Saphrs OF THE LAKE NIPIGON BASIN BY ALFRED W. G. WILSON (Read before the Society December 31, 1908) CONTENTS Page PmacITOn mama Seneral LEVIEW .. sais. cn ee ek eles cca sees wacscucven 198 SMa HOM OF CMErUEADS 14.65 on © cates 0s bla cle cles whine Se eee Leahaaial winrerant 198 AO Aec NN OCU MEMOS main «a's Gil e 0 a opa cha cuctantcle GAM okiacste oGkdte a ee eee 198 CMe Om NCE MOGIOIT., . seostn aces Ga shor elene Sue vias ee Mihbduw se ghia eitete ca MPa a « 200 Memarmmine Mresent GISCUSSION. ... 5.6... c.c ea eceed wueu ces deancuccnees 201 eam Mo mOlnCTNUICAl (ATCA. sia. «oo < eo ei disie berate als gs ebb ode ales becuse ee 202 “, AVEINGICAI| oo o'e otter tellaks eR leo itede ciabatta, Zi ean aes Ne eg eee 202 ote mO MR CUINT OLSON UV CL aid cuir cls cic he ce-a o 08 Hale 0 ae welche Slo d vib gg ees 202 UIST EUTEIV® TDINGIAT MGs SaRae ene aetace Cie ce elec St aia hors acre ame gee es So ey 203 manne Sem RTE ONE LO alana, ance hay oi seNe Seay igre a Sake BWSe aI ha Aide he DE 204 Penh SOT ENONUISE SOUMPIIENS ¢ 5 .b.27) fcc ais ola ale a wines Cocke ale wa @ ocd clelecain oleae 205 ere MRI MNT Vea eats e-finyi=s ai hss ciate nee aeteNs vide alone swear eb bok Seu o Coe dele weg omens 205 MeamR TMM METNMITOVVIS crater oravaterals, slcleia slale we gah kee 'sree 0 ne tele cuwc lic Cane cen 206 Pea lesremnmants, Of Old SOLIS 77 Sibb. 2.0.0.5. ec ee ec cee cece ace 207 PEER MENCVICCTICO se 60. bce ode ula cle ee eucls dee ee deeechbwceuwes 209 Pee MLONUS EL CI SA/S LMETIISTONIG). coor. 4a. os Sascebe, w wate wow adie Sw dooce wa wld 209 PiEeaeMNIENeS OL GHEE EY POS. ic .6 iva oc. se Gina eves acess © clei aca been eas Zien Pome rchme War AaGteriStiCS os ).n0l.8s ike. oo 4 Kiepe nc os Sin enla ocean ol seeks Ziel Pee MPO SMOlMCACMabV We. Ne sie tic ccs Sheers ob hie ag oa a oeaTas S Petal EL SIGSOI Ge rect AR RL SALA ome Ae ot ae wt DANES ee MIU TEMES UNIQUE LGC Vre ca cates sia hee ote) sonetale sok See Cave oid on cere es Sahn eho s 215 Mun avanOn stine evidence available...) 2.0.00. cscs es bee es ese cccbacees PAN) Lin) AOI OIE TRAE DISI 52a 50) BISTRO Ze ImTOO Mas SUN ACE LOW Sick, neucre cadrone'e ssi aloietis ici a wiate Bu bb Seeds bls oe Ske 216 PLE Te TERS EVEN IES AUC SO CC me na en JAG See Me Of LHe MOWS. ihc cle ss aye cules dc.Gawe ness hae cee oe debe. 2G Character of the preexisting topography and date of denudation.......... 219 | STIPTETOTD, GED TESS DEE 1S (=e a 2G Summary of the post-Cretaceous geologic J RUS CO Baier tsccie tess gue en ee 222 * Published by permission of the Director of the Geological Survey of Canada. Manuscript received by the Secretary of the Society February 2, 1909. XVII—BUvuL.. Grou. Soc. AM., VoL. 20, 1908 Gig7) 198 A.W. G. WILSON—TRAP SHEETS OF LAKE NIPIGON BASIN INTRODUCTION AND GENERAL REVIEW DISTRIBUTION OF THE TRAPS Along the north shore of lake Superior from the Slate islands to Pigeon river, and extending over an area reaching to more than 1)0 miles north of the Canadian Pacific railway, the most prominent geologic feature is the occurrence of large areas in which trap sheets predominate. Within this area practically every salient feature of the topography is found to be associated with these trap sheets. Along the southern edge of the district, and extending for about 40 miles north of the Canadian Pacific Railway line, the traps are constantly found in association with Keweenawan and Animikie sediments. In the northern part of the area, in the basin of lake Nipigon, residual patches of Keweenawan sediments are frequently found associated with the traps, but there are numerous localities where the igneous rock rests directly upon the older Archean rocks. The variegated, bold, and picturesque topography seen along the line of the Canadian Pacific railway from Rossport to West Fort William, Red Rock at the mouth of the Nipigon river, McKay mountain at Fort William, Pie island, and Thunder cape are a few of the many salients familiar to any one who has journeyed by boat or rail to Port Arthur or Fort Wiliam. The gorge of the Nipigon river from north of lake Jessie is cut through one of these immense sheets, and the less well known but more picturesque canyon which forms Pijitawabikong bay, a few miles east of the Nipigon river, 1s also cut through the same sheet. Usually these trap sheets are nearly horizontal and of great extent. The largest single continuous area, so far explored, lies in the basin of lake Nipigon, south and southwest of the lake itself. The sheets occur either as sills from 4 to more than 50 feet in thickness, intercalated within the sandstones, shales, or dolomites, or in the form of capping sheets — from 12 to more than 500 feet in thickness. These caps stand at the summit of the local stratigraphic column and their upper surface usually is a tableland or mesa. PETROGRAPHY OF THE TRAPS As to the petrographic characters of the trap sheets it may be noted that diabase is by far the most abundant rock, olivine being present fre- quently in large amount. Structurally it may pass from a typical diabase, the prevailing rock, to a coarse gabbro or olivine gabbro, or locally to a fine grained porphyrite. The ophitic structure is the most prominent and widespread. The texture, except at the contacts with the AREAL DISTRIBUTION OF THE PRINCIPAL FORMATIONS Grass L. ae yet ee) wan) + + ory > Qs rete Ta yteate et + + So + +745 + eer + + 4 + +e +? ore + ++ ff ¢ a* vs LEGEND. ARCHEAN KEWEENAWAN DIABASE Fs Seale in miles. 10 FiGcgurRE 1.—Sketch Plan of Lake Nipigon Basin Showing the areal distribution of the principal bedrock formations 200 A.W. G. WILSON—-TRAP SHEETS OF LAKE NIPIGON BASIN earlier rocks, varies from medium to coarse; usually it is nearly uniform throughout the thickness of the whole sheet, except close or near to the basal and upper contacts, even where the sheets are several hundred feet in thickness. ‘The sheets of diabase, with a few local exceptions, are re- markably constant in their petrographic characters over nearly the whole area. They are invariably holocrystalline and are never amygdaloidal. VIEWS AS TO THEIR ORIGIN The earlier students of the district regarded these diabase sheets, in whole or in part, as volcanic flows, the lower and thinner intrusive sheets being considered as contemporaneous with the sedimentary rocks with which they are associated, while the capping sheet was designated the “Crowning overflow” by Sir William Logan. Later work by Ingall? and by Lawson? has combatted these ideas, and the view so admirably set forth by Lawson has come to be generally accepted. Lawson’s thesis is (page 29) : “There are no contemporaneous volcanic rocks in the Animikie group. “None of the trap sheets associated with the Animikie, whether of the na- ture of ‘caps’ or intercalated sheets, is a voleanic flow. 5 “These trap sheets are all intrusive in their origin and are of the nature of laccolitie sills.” Lawson further summarizes the data on which he founds this thesis in the following statement (page 44) : “T. The trap sheets associated with the Animikie strata are not voleanic flows because of the combination of the following facts: “1. They are simple geologie units, not a series of overlapping sheets. “2. They are fiat, with uniform thickness over more than one hundred Square miles in extent, and where inclined the dip is due essentially to fault- ing and tilting. “3. There are no pyroclastic rocks associated with them. “4, They are never glassy. “). They are never amygdaloidal. “6. They exhibit no flow structure. . They have no ropy or wrinkled surface. “8. They have no lava breccia associated with them. “9. They came in contact with the slates after the latter were hard and brittle and had acquired their cleavage, yet they never repose upon a surface which has been exposed to:subaerial weathering. “II. They are intrusive sills because of the combination of the following facts: 2H. D. Ingall: “Mines and mining on lake Superior.’’ Geological survey of Canada, 1888, vol. ii, part 2, section H, pp. 42, 46, 79, 80, 99. 8 A. C. Lawson: “The Laccolitic sills of the northwest coast of lake Superior.” Minne- sota Geological Survey, Bulletin viii, 1893. VIEWS AS TO ORIGIN 201 “1, They are strictly analogous to the great dikes of the region: (@) In their general relations to the adjacent rocks and in their field aspect. (0b) In that both the upper and lower sides of the sheets have the facies of a dense aphan- itic rock, which grades toward the middle into a coarsely crystalline rock. “2. They have practically a uniform thickness over large areas. “2 The columnar structure extends from the lower surface to the upper surface, as it does from wall to wall in dikes. “4, They intersected the strata above and below them after the latter had been hard and brittle. “5. They may be observed in direct continuity with dikes. “6. They pass from one horizon to another. “7 The bottom of the sedimentary strata above them, wherever it is ob- servable, is a freshly ruptured surface. “8. Apophyses of the trap pass from the main sheet into the cracks of the slate above and below. “9, The trap sheets, particularly at the upper contact, hold included frag- ments of the overlying slates. “10. They locally alter the slates above and below them.” For purposes of discussion the diabase sheets may be divided into two great groups: That group of sheets both the upper and lower surfaces of which are known or can be readily inferred, and a group consisting of all those sheets whose under surface only is known—the group of sheets which forms the various topographic “caps” throughout the whole region. _ With reference to the first group, the observations of the writer, con- ducted over a wider area, emphatically confirm Lawson’s conclusions as outlined above. With reference to the capping sheets, the writer’s obscr- vations are in accord with Lawson so far as the areas examined by both are concerned, but data obtained largely in the basin of lake Nipigon lead him to make a somewhat different interpretation of facts noted both by Lawson and himself, and to different conclusions. SCOPE OF THE PRESENT DISCUSSION The writer wishes to confine the present discussion wholly to the con- sideration of the nature of the relations which now exist, and possibly formerly existed, between that group of sheets of diabase which now form the “caps” and the underlying rocks. So far as all other masses of diabase within the area are concerned, his observations confirm in every respect those of Lawson. Hence that there are a group of diabase sheets in this region which are not volcanic flows but which are intrusive sills of a laccolitic type is not a subject of discussion in this paper. With reference to the “caps,” it must be recognized at the outset that the only contact surfaces we can study are those at the base. The char- acter of the upper surface and the nature of the contacts, if any, can be 202 7s 2 m SCALE z 1"=85 miles FIGURE 1.—Map of the Vicinity of Silver Peak Range - J. H. Spurr in his paper,* “Ore deposits of the Silver Peak quadrangle.” A generalized geological map, taken from my detailed map, was publishea ‘Professional paper no. 55, U. S. Geological Survey, 1906, 296 H.W. TURNER—-GEOLOGY OF THE SILVER PEAK QUADRANGLE by Mr Spurr, and this map may assist the reader of the present paper in getting an idea of the geology of this interesting region. Many Cambrian fossils were collected, mostly in an excellent state of preser- vation, which, with others obtained later by F. B. Weeks, probably wiil be made the basis of future publications by the U. S. Geological Survey. On his generalized geological map the rocks here included under “pre- Cambrian complex” are called by Spurr “Intrusive granitic rocks com- plexly injecting Paleozoic strata.” This, however, is misleading, inas- much as the complex is composed largely of gneisses and schists which were probably made gneissic and schistose before the Cambrian was laid down, and in that case would not be intrusive in the Cambrian. How- ever, the white granite and pegmatite associated with these ancient gneisses are intrusive to some extent in the basal green schists, quartzite, and dolomite which underlie the fossiliferous Cambrian rocks. As this white granite is intimately associated with the pre-Cambrian, it was mapped and described as a part of the pre-Cambrian complex, although evidently later in age than the bulk of the gneisses and schists which are intruded by it. This latter granite (alaskite of Spurr) and pegmatite was nowhere seen intruded in fossiliferous Cambrian rocks. The evidence of the continuity of sedimentation from the Upper Cam- brian into the graptohte beds of the Ordovician appears to be quite plain in one section near Emigrant pass, at the north end of the Silver Peak range. Further collections from this section should bring forth interesting data. There is probably no field in Nevada where there are better exposures of the older Paleozoic series, and the region merits fuller investigation. GEOGRAPHIC FEATURES EXTENT AND TOPOGRAPHY OF THE QUADRANGLE The Silver Peak quadrangle comprises a portion of the Great basin lying immediately east of the Inyo mountains. It is thus in the western part of the Basin region. It is limited by the parallels of 37° 30’ and 38° north latitude and by the meridians 117° 30’ and 118° west longi- tude. The larger portion of the area lies in Esmeralda county, Nevada, but the extreme southwest corner is in Mono county, California. There are portions of several mountain groups represented in the quadrangle, including nearly all of the Silver Peak range. In the northeast corner are the foothills of Lone mountain; along the east border are the foothills of the Montezuma mountains; near the southeast border the Palmetto mountains, and the hills in the extreme southwest corner belong to the GEOGRAPHIC FEATURES DIT Inyo range. Occupying the depressions between these groups of moun- tains are extensive valleys, that between the north end of the Silver Peak range and Lone mountain being known as Big Smoky valley, that between the Silver Peak range and Montezuma mountains as Clayton valley, and that on the west, between the Silver Peak range and the Inyo range, as Fish Lake valley. The lowest portions of each of these valleys form playas, covered with an incrustation of various salts, white in color, ren- dering them a conspicuous feature in the landscape. The ranges are nearly all quite complex in character. None of them can be said to represent the typical Basin Range structure. However, the steep slopes of several of them are clearly the result of uplifts along | normal faults. To this extent the Basin Range structure may be said to be represented. The details of these structure features will be given under a separate heading. DRAINAGE The drainage system consists of waterways, or “washes,” which radiate from the ridges toward the valleys. These waterways are ravines and canyons of the ordinary Basin type. On the slopes between the edge of the mountain ridges and the lowest points of the valleys the “washes” are cut chiefly through the older alluvial fans and through Tertiary lake beds. In such cases the banks are commonly precipitous, with a maxi- mum height of about 250 feet. There is usually a flat bottom to such washes, up which one may drive with a light vehicle for long distances, As previously stated, none of these “washes” contains any permanent stream, with the exception of a single ravine hereafter noted. Even after rains the running water in the “washes” seldom reaches the playas of the valleys, and the thin sheets of water covering these playas after rains represent chiefly the material which has fallen on the playas themselves or on their margin. An exception to this is Fish Lake valley, where floods from the Inyo range frequently spread out over the valley. Nearly all the precipitation within the quadrangle either sinks immediately into the ground or is carried down on to the detrital slopes and there dis- appears, while that in the playas is gradually evaporated. WATER SUPPLY Within the limits of the quadrangle, except after rains, there is no running water whatever except the stream, less than a mile in length, which issues from the Jeff Davis spring, on the east slope of Silver Peak range. If it were not for the occasional springs scattered over the quad- rangle and the possibility of getting water by sinking wells, the region 228 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE would be practically uninhabited. Some of the springs, however, supply an abundance of good drinking water, while others contain so much alkali as not to be of value for domestic use. Near Silver Peak there is a hot spring with a temperature of 132° Fahrenheit (November, 1900), containing a large amount of chloride of sodium, while a few feet away is a cool spring. The best available water in the district comes from springs along the summit of the Silver Peak range to the west and south of Red mountain and along the north base of the Palmetto moun- tains. At Silver Peak there is a pond in which there is water standing the year round, and another, known as Fish lake, may be seen in Fish Lake valley. PRECIPITATION _ No systematic records for any great length of time have been kept within the limits of the quadrangle, but the records at Hawthorne, Soda- ville, and Palmetto, all points in Esmeralda county, indicate that the average annual precipitation varies from 3 and 5-10 inches in the valleys to 15 inches on the highest ridges. It frequently rains or snows on the mountain tops when the neighboring valleys receive no precipitation whatever. SCENERY Except on the higher ridges and about some of the marshes, the vege- tation of the region ordinarily presents a gray effect; but the general somber tints are relieved at some points by the varied and sometimes even brilliant colors shown by the rocks. The ridges being usually devoid of soil, the colors of the rocks are conspicuous. The Cam- brian rocks are dark limestones, buff marbles, green quartzites, schists, and slates. The Ordovician rocks are usually black siliceous argillites and gray and red slates. The Tertiary lake beds are chiefly light buff shales, tawny sandstones, and tern gray marls. By far the most brilliant colors are those of the volcanic rocks. The basalts and basic andesites are usually dark brown or black, but the rhyolites exhibit great diversity. In a little group of rhyolite hills may be noted buttes of dark brown rhyo- lite—the color in this case being mostly the effect of surface weathering— slopes of cream and pink tuffs, and little hillocks of a bright brick red. This is particularly true of the north portion of the Silver Peak range, the north face of which exhibits a series of horizontally bedded rhyolite tuffs and breccias of diverse colors (figure 2, plate 9). At other points the rhyolite is of a green color. A chemical examination of this rock by Doctor Hillebrand showed that the green coloring material is probably an iron silicate. It does not contain chromium. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 6 FricturE 1.—RUYOLITH-TUFF, WEATHERED INTO GROUPS OF CONES FIGURE 2.—SINGLH WHITE CONE 20 FEET IN HEIGHT RHYOLITE-TUFF AND SINGLE CONE GEOGRAPHIC FEATURES 229 The rhyolite tuffs often weather in curious forms. Figure 1, plate 6, represents a group of little white cones at the northwest base of the Palmetto mountains, in the little cavities of which small rodents make their nests; figure 2, plate 6, shows a single one of these cones, which is perhaps 20 feet in height. DESERT VARNISH On the detrital slopes many of the boulders of lava and other rocks are covered with a dark brown shining coating, known as desert varnish. Some of this material was examined by Dr H. N. Stokes, who found it to be chiefly manganese dioxide. Under this outer coating in the basalt boulder examined, there is a decomposed layer in which Doctor Stokes determined the presence of a silicate soluble in hydrochloric acid and containing alumina and lime. This silicate is not feldspar, since it is soluble in acid. Oscar Loew® regards the desert varnish of the Mojave desert as having been deposited on the rocks as carbonate of manganese by the retreating waters of a shallow ocean which he supposes once covered that desert. The binoxide of manganese was then formed froin the carbonate by the action of sunlight and air. Doctor Loew placed a granite boulder weighing 80 grams in hydrochloric acid until it showed its natural color. The material in solution in the acid was as follows: Grams SCCM ORAL a OL MUR OM: che cyetare ao ch ae aci cao she eres wiorarci'e's oe 0.078 Perper: Of MMANPATICSE ca. 5 6 eed wos ore « Sree pid os Sieteree o's 0.038 EEG) CLE SUG (2) Sle a trace Dr G. P. Merrill® investigated the desert varnish on pebbles of quartz- ite in Toole valley, Utah, which was formerly covered with the waters of lake Bonneville. He found that the coating gave reactions for iron and manganese. He writes: “Tt is evident that the exterior coloring of the desert varnish is due mainly to a local segregation of oxide of iron with a little manganese and organic matter. All things considered, it seems safe to assume that this local discolor- ation is due to a superficial segregation of the metallic contents of the quartz- ite in a state of higher oxidation, the iron originally in the form of a carbonate being converted into a hydrated oxide, while the lime carbonate itself was re- moved in solution. The small amount of organic matter may have been added from external sources from the water of the original lake.” There is no evidence that the detrital slope in Clayton valley from which the specimen of desert varnish examined by Doctor Stokes was 5 Wheeler Survey; Annual Report for 1876, Appendix JJ, p. 179. ® Bulletin no. 150, U. S. Geological Survey, pp. 389-391. 230 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE collected was ever covered with standing water. Nevertheless, Merrill’s hypothesis, that the desert varnish is due to a local segregation of the metallic contents of the rocks on which it occurs, seems to best account for the varnish. It is found only on the upper exposed surfaces and on slopes that have been exposed to the elements for a long period, not being observable on the boulders of the newer washes and alluvial fans. PRE-CAMBRIAN COMPLEX LOCATION AND COMPOSITION OF THE COMPLEX Within the limits of the quadrangle, there are two areas which are regarded as pre-Cambrian in age. One of these forms the larger part of Mineral ridge, west of Silver Peak village, and the other, a small area, lies 5 miles northeast of B. M. 4996, in the northeast part of the quad- rangle and just west of an area of the basal dolomite. This dolomite is placed for convenience with the Lower Cambrian. ‘These areas seem to represent the oldest rocks of the district, and this complex distinctly underlies the Lower Cambrian beds. The complex is composed of granite-gneiss, quartz-monzonite-gneiss, granite-augen-schists, calcareous augen-schists, and small lenses of hydrous mica-schists. THE GNEISSES The gneisses vary in composition. Some of them are true granite- gneisses, in which the feldspar is chiefly orthoclase, and such gneisses usually contain muscovite or white mica often with some biotite. A second kind may be called quartz-monzonite-gneiss or a granodiorite- gneiss, since it contains both orthoclase and plagioclase in approximately equal amounts, and in this type the predominating mica is biotite. A partial analysis of one of the quartz-monzonite-gneisses (number 224) by George Steiger gives the following results: ili@ay ss. 258) eh iste ee eee ee Se ee eee 69.34 PRIME oer Sb os Bn ee Ae oe Cee eee Zoo Soda. S205.) Je). cee eee eee 4.51 POLASN 65 63 e523. Seid fos e Da peas oe SE eee 3.19 At some points where these two gneisses occur together, there seems to be evidence that one is intrusive in the other, but the evidence as to the relative age of the two is not consistent at different points, the granite-gneiss apparently being older at one locality and the quartz- monzonite-gneiss at another. Other gneisses, similar in general appear- ance to the above, contain chiefly plagioclase, thus forming a quartz- BULL. GEOL. SOC. AM. VOES 20; 1920S rea FIGURE 2.—CALCAREOUS AUGEN-SCHIST CALCAREOUS AUGEN-SCHIST ROCKS OF THE PRE-CAMBRIAN COMPLEX Werk diorite-gneiss. When any two of these gneisses are in contact the gneissic structure of the one is found to be parallel to that of the other. THE SCHISTS The schists always appear to overlie the gneisses. They are of two kinds. One has the composition of a granite and shows under the micro- scope strong evidence of shearing, the feldspar and quartz grains being erushed and faulted and largely reduced to minute granules. In this schistose granulated groundmass large grains of quartz, feldspar, and muscovite form kernels or augen, around which the lines of granules and the lines of muscovite of presumably secondary origin curve. Such a rock may be designated a granite-augen-schist. The other type of schist weathers a brown color, strongly resembling sedimentary limestone. It often contains streaks and augen of the white granite, as shown by figure 2, plate 7. On a large scale the same thing may be seen at many © points, but nowhere better than in the ravine which leads up to the Great Gulch mine, where the streaks of granite are often several inches in diameter, producing the impression of intrusive sheets in the darker schist. The rocks are here greatly plicated, and as the streaks of granite are involved in this plication, it is evident that the plication occurred after the intrusion. Some of the more massive occurrences of this type of schist show no augen to the unaided eye. At the west base of the ridge of Lower Cambrian rocks, with an altitude of 8,400 feet, which lies about 3 miles north of Red mountain, immediately underlying the Lower Cambrian limestone, are certain dark rocks resembling slates, in which are dikelike streaks of the coarse white granite at one or two points. ‘These slate-like rocks were at first supposed to be a part of the Cambrian series, but the microscope shows them to be of essentially the same composition as the schists above described, and hence they are mapped as a part of the complex. While these schists vary in macroscopic appearance, under the microscope these differences are less striking. The fine grained schists and slaty rocks are found to always contain grains or augen of feldspar or quartz, or both, and often of secondary minerals, including an epidote-like mineral, in a groundmass of minute grains of carbonate of lime. The fine grained portions of the coarser calcareous augen-schists, represented by figure 1, plate 7, are an exact facsimile in some cases, as seen under the microscope, of the fine grained schists, which, when massive, so strongly resemble sedimentary limestone on ex- posed surfaces (see figure 2, plate 7). Nearly all of the thin-sections show evidence of strong shearing or mashing, the original grains being thoroughly crushed and arranged in 232 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE parallel streaks. Such of the grains as have not been granulated are fractured and rounded and the quartzes usually show undulous extine- tion. Lines of mica foils, chiefly finely divided muscovite, contribute greatly to the formation of the schistose structure. While the two types of schists here described are very different in chemical composition—the granite-augen-schist having the composition of granite or of arkose, and the lime-rich extreme of the calcareous augen-schists the composition of an impure limestone—at numerous points schists representing transitions from one to the other may be found. Such a series, all taken from one bluff about 1 mile southeast of North spring, shows transitions from a typical granite-augen-schist composed of lines of minute grains of quartz and feldspar and of minute muscovite foils in which are imbedded large grains of feldspar and quartz and muscovite foils with little or no car- bonate to a granite-augen-schist similar to that just described, but with lines of carbonate granules in addition. The calcareous augen-schists may represent thin bedded limestone and lime shales thoroughly injected and infiltrated with granitic material. Analyses of calcareous Augen-Schists and of Granite-Augen-Schists George Steiger, Analyst sf ES Ge hes. Number | Number Number Number Number 787 736. | 744. 1° qe SiO; sede Se ee ee | 27.45 | 30.31 | 6259 | 7148 | a7eae CAO SEE 6 2. pare eee |. BAAG- 16 29> ol oe 1.500 41> ee Nai) oe a ah ne eee | | 54 86 | 3.76 3.35 | 4.26 tt ee eh eee Wheres se 1.87 oA ta ae 3.85 | B80 CO ris. ye Sees SAS) | ial) eso8 1.03 | 2B Numbers 787 and 736 are of the type designated calcareous augen-schists. and numbers 7H, 733, and 734 are typical granite-augen-schists. THE WHITE GRANITE The white granite (alaskite of Spurr) was nowhere observed certainly intrusive in fossiliferous Cambrian or later sediments. It is usually a coarse grained rock, composed of orthoclase or potash-feldspar, with some albite or soda-feldspar and frequently some muscovite, but it is often nearly destitute of black mica. By the loss of quartz it grades over into syenite. There is sometimes plagioclase present. The following partial analyses of white granite (alaskite) by George Steiger indicate the chemical composition : Atti, tat ee ee a ROCKS OF THE PRE-CAMBRIAN COMPLEX V3) Analyses of the White Granite (Alaskite) Number | Number | Number 467. 209. Pali): SHE oa 5 Saha ERR RD De CO a ee en ener ae 70.80 V2atz2 73.59 SASS. oo oll fie ee ee ee eer le OL .49 ee. a aR IRIRES EEE Ao oer a em aN 3.95 1.65 3.62 Potash 20 ee ae ae ae ee sr ern Re oe 3.83 6.93 Aste Granite number 467 is from 6.3 kilometers west of north from Red mountain. Collected at the edge of an included mass of marble. Dikes of this rock are in the dolomitic marble. Macroscopically, a coarse grained nearly white rock, apparently composed chiefly of feldspar. Microscopically, an even grained rock composed of feldspar, quartz, and muscovite. The feldspar is microcline and plagioclase. There are present minute zircons. Carbonate of lime is rather abundant in cracks and between the grains of the primary constituents, which are fresh. The rock shows evidence of crushing. The quartz is in inter- locking, in part elongated, grains showing undulous extinction. Granite number 259 is from the lower tunnel of the Mary mine. Macroscop- ically, it is a light gray granite showing white feldspar, quartz, and biotite. Microscopically, it is composed of microcline and orthaclase, quartz, oligoclase, biotite, muscovite, zircon, and apatite. There is a little carbonate and chlorite present. The rock shows no evidence of crushing or shearing. Granite-gneiss number 210 is from a dike in quartz-schist 1.5 kilometers northwest of the Silver Peak benchmark. This quartz-schist underlies the lower Cambrian. Macroscopically, it is a white gneissic granite containing muscovite. It is evidently a sheared form of white granite. Microscopically, it is composed of orthoclase, albite, quartz, plagioclase, and muscovite. One minute garnet was noted. The rock has been strongly sheared, the feldspars and quartzes being fractured and granulated. It is now a granite-gneiss. Some of the pegmatite dikes seem to be genetically related to the white granite, and these dikes are very clearly later than the gneisses, for they cut across the gneissic banding. The high cliff which forms the west wall of the deep north-south canyon that les about 114 miles northwest of the New York canyon is formed from top to bottom of alternating lenses of the white granite and augen-schist. ‘These lenses or layers lie nearly horizontally. If we sup- pose the lenses of white granite to be intrusive sheets in the augen-schists, their lens-character and their lack of continuity may be regarded as due to pressure exerted after the intrusion. The gneissic and schistose structures of the pre-Cambrian gneisses and schists above described are usually roughly parallel with the bedding of 7™The high content of lime in this specimen is plainly due to carbonate of lime infil- trated into cracks, as shown by the microscope. The rock is fresh and a true granite. 234 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE the overlying Cambrian sediments. Where the Cambrian rocks have been disturbed, the pre-Cambrian rocks have likewise been disturbed; where they lie nearly horizontally, the same is true of the underlying rocks. The crushing and recrystallization of the rocks of the pre-Cambrian appears thus to have been effected without tilting or folding, and pre- sumably occurred before the deposition of the Lower Cambrian sedi- ments, for in these there is little evidence of a schistose structure or of recrystallization, the slates or shales often containing recognizable Olenel- lus and other fossils not far from the contact of the pre-Cambrian with the Cambrian. This would likewise suggest that the white granite in- volved with the augen-gneisses is older than the Cambrian, as otherwise its intrusion would have produced contact metamorphic effects on the Cambrian sediments, and that the dikes of white granite which at some points intrude the basal dolomitic rocks are of later origin than the gneisses of the complex and of the same age as the coarse pegmatite dikes, from which they differ but little in chemical composition. How hori- zontal gneissic and schistose structures may be produced is difficult to explain, but probably they developed under a great superincumbent mass of beds now eroded. Much finer examples of flat lying gneisses are described by Dr Frank D. Adams® in Canada. This area of gneisses is referred by Doctor Adams to the Grenville series. In these gneisses are interpolated occasional bands of crystalline limestone and of quartzite. Over an area of at least 750 square miles the gneisses lie quite flat, or et most dip at an angle of 30 degrees. In one of the illustrations in Doctor Adams’ paper (plate III, p. 13-7) a bluff of these horizontal gneisses is depicted which might readily be mistaken for undisturbed sedimentary rocks at a little distance. ! Dr George M. Dawson,° in his presidential address before the Geolog- ical Society of America, in describing the Shuswap series of the Rocky mountains in Canada, indicates a relation between the Archean and Cambrian similar to that above described on Mineral ridge. He writes: “A distinct tendency to parallelism of the strata of foliation with adjacent borders of the Cambrian system has, moreover, also been noted in a number of eases. This might imply that the foliation was largely produced at a time later than the Cambrian, but the materials of some of the Cambrian rocks show that the Shuswap series must have fully assumed their crystalline character before the Cambrian period, and there are other evidences of their extensive pre-Cambrian erosion. It seems, therefore, probable that the foliation of the 8 Geological Survey of Canada; Report of progress, 1895, vol. viii. Report by Frank D. Adams on the geology of a portion of the Laurentian area lying to the north of the island of Montreal, pp. 11-7. ® Bull. Geol. Soc. Am., vol. 12, 1901, pp. 57-92. ROCKS OF THE PRE-CAMBRIAN COMPLEX 935 Shuswap rocks may have been produced rather beneath the mere weight of superincumbent strata than by pressure of a tangential character accompanied by folding, and that both these rocks and those of the Cambrian were at a later date folded together.” In the foregoing it has been implied that the gneissic and schistose structures of the pre-Cambrian of Mineral ridge were developed in pre- Cambrian time, and that the planes of these structures were approxi- mately horizontal. On this hypothetical horizontal floor the Algonkian (if present) and Lower Cambrian sediments were deposited. ‘These are in large part fine grained quartzite, limestone, and shale, suggesting quiet conditions. Basal conglomerates are wanting. It may be held that if the rocks described as pre-Cambrian are really so, distinct evidence of an unconformity with the overlying Lower Cambrian should be observable. This, however, loses weight when we consider that the Lower Cambrian sediments, chiefly shale and limestone, must have been laid down in quiet water and, as supposed, on a nearly horizontal floor. Under these condi- tions basal conglomerates would not readily form. Moreover, the proof of strong stresses having been applied to the pre-Cambrian complex re- sulting in thorough gneissic and schistose structures, while the overlying Cambrian shows no such evidence of stresses, certainly suggests a con- siderable difference in age. An old eroded surface is usually an irregular surface, but on account of disturbances subsequent to Lower Cambrian time, and on account of the erosion of the larger part of this old eroded surface of the pre- Cambrian of Mineral ridge, no satisfactory evidence was obtained as to its contours. Lying on top of the pre-Cambrian of Mineral ridge are two ridges composed of Lower Cambrian sediments. The even line of contact of the pre-Cambrian with these Lower Cambrian beds suggests that the hypothetical old eroded surface is not very irregular. GRANITIC QUARTZ-VEINS In addition to ordinary quartz veins in the pre-Cambrian, there are other veins and bunches of quartz which appear to represent the acid extreme of granitic dikes. Such veins usually contain a little feldspar and white mica, while others to which a similar origin may be assigned contain none. Assays were made of the quartz from two of these veins and only one of them showed the presence of gold. No sulphides have been noted in them. The quartz has often a banded structure, due, as shown by the thin-sections, to crushing and subsequent recrystallization, the granules of quartz being drawn out in parallel lines, so that some specimens might be called quartz-gneiss. This granitic quartz is usually 236 H.W. TURNER—-GEOLOGY OF THE SILVER PEAK QUADRANGLE of a dull or bluish color, precisely like some of the quartz-augen in the white granite where it has undergone crushing. The dull color is proba- bly due to the innumerable dots, visible only under the microscope in the thin-sections. These dots when examined with a high power are in part resolved into minute cavities containing one or more gas bubbles in a fluid, but most of the dots are indeterminable. One of the thin-sections examined showed plainly a crushing of the rock, the large quartzes being broken and faulted. Two specimens assayed for the precious metals by the Selby Smelting and Lead Company gave the following results: Gold Silver in ounces. in ounces. ING:* 4938. ceca eis Soe ee OL eee 0.03 OAS No: 500: 2b. eee eee eee none none It should be stated that no mica or feldspar was observed in quartz vein number 493, which alone contains gold and silver. The following detailed description of thin-sections of the assayed granitic quartz taken from two of these veins indicate their appearance under the microscope: Specimen 493.—Locality: Mineral ridge, on the same spur as the Mary mine. Specimen was taken from the vein lying just east of and overlying the Crown- ing Glory ledge. Macroscopiecally, a dull bluish white quartz showing irregular fractures. Microscopically, a quartz rock evidently composed originally of large quartzes with uniform orientation throughout, but these grains have been erushed and faulted. The lines of shearing cut the large quartz grains in various direc- tions. Most of the quartzes show undulous extinction. Specimen 500.—Locality: 7.5 kilometers east of Red mountain, on Mineral - ridge. The vein is about one meter thick. Macroscopically, a bluish quartz containing some feldspar and white mica and possessing a gneissic structure. Microscopically, a quartz-gneiss in which the grains dovetail and are often elongated in one direction, producing a gneissic banding. The quartzes are turbid, and this appears to be due to in- numerable minute dots mostly arranged in parallel rows, but these rows cut the gneissic banding at an angle. This quartz must have undergone deforma- tion either when consolidating or subsequently. The lines of dots were un- doubtedly formed at the time of consolidation, and as these are not parallel to the gneissic banding, the inference may be drawn that the gneissie structure is due to stresses exerted after consolidation. At one point there are phenocrysts of feldspar which show narrow lamellar twins with small extinction angle on the trace of the twinning plane. The index of refraction of this feldspar is greater than that of the balsam. It is probably oligoclase. Many instances have been recorded of veins or dikes of quartz similar to those above described. Lehmann’? has found them in Germany, —_ 7 Lehmann: Untersuchung ueber die Entstchung die altkrystal-linischen Schiefer- gesteine. Bonn, 1884. ROCKS OF THE PRE-CAMBRIAN COMPLEX eT Hussak" in Brazil, and Crosby and Fuller,’ Williams,** Van Hise,!* and others in the United States, and J. E. Spurr’® in Alaska. According to Hussak, the granitic quartz veins in certain instances build narrow contact zones in the slates which they intrude. Such zones would not be very noticeable, except when the veins or dikes are in rocks rich in alumina or lime which readily recrystallize into alumina and lime silicates. DIORITE DIKES In addition to dikes of the white granite (alaskite), there are numer- ous dark green dikes, usually less than 10 feet in width, but of much greater longitudinal dimensions. These will be referred to in general as diorite dikes, although some of them contain too little feldspar to be properly designated by that name. They are composed of green horn- blende and plagioclase (andesine and labradorite), with accessory apatite, ilmenite, and other minerals, together with secondary products, such as epidote, chlorite, and carbonate of lime. At some points these diorite dikes grade over into hornblendite by loss of feldspar. For ordinary purposes they may be called greenstone. These dikes are evidently later than all the other rocks of the complex, for they cut across the gneissic and schistose structures, and frequently show at the border a fine grained layer or salband, due to the more rapid cooling of the intrusive magma where in contact with the wall rocks. These salbands are to be noted where the dikes are in contact with the white granite and the quartz veins, and hence later than these rocks. The following analyses are of two of the more basic dikes, neither of these being true diorites: Analyses of Greenstone dioritic Dikes from Mineral Ridge George Steiger, Analyst Number 208. | Number 222. SULWCCz 2 RR RNa an ai te Mei Iam RRS. AMR ciate, age 48.67 46.28 TET EEN, So OGG Sao e chet oor Sera EE sane On pe Sen 8.75 19.54 Rl PE rr A ote h, chateicte so Gieveje ad x e's abun wre 8.58 9.91 SUDA oc. 9) Shale eee Pn arog ON ann eat MIU ar PS SG ieee boc a aks Wu itre kle sts e ws « da acess .99 1.89 1 Hussak: Zeits. ftir Praktische Geologie, 1898, p. 356. 12 Crosby and Fuller: American Geologist, vol. xix, 1897, pp. 156-178. 1% G. H. Williams: Origin of Maryland pegmatites. Fifteenth Annual Report of the U. S. Geological Survey, p. 679. 144C. R. Van Hise: Principles of the North American pre-Cambrian geology. Sixteenth Annual Report of the U. S. Geological Survey, part i, 1896, p. 688. Prof. Van Hise also treats of this subject in his fine monograph on metamorphism. 18 J. E. Spurr: Geology of the Yukon district, Alaska. Eighteenth Annual Report of the Geological Survey, part iii, 1898, pp. 101-392. The notes on granitic quartz veins presented here were enlarged on by J. IE. Spurr in Professional Paper of the U. S. Geological Survey, no. 55, and many additional data presented, 938 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE Number 208 is from 1.1 kilometers northwest of the Silver Peak benchmark. It is a multiple dike along a dike of white granite which is broken up and in- truded by the greenstone. The latter sends branches in between layers of the white granite. These branches show salbands. The rock is composed chiefly of green-brown amphibole in idiomorphic needless and lime-soda feldspar which is too altered to determine its exact nature. Number 222 is from 2.5 kilometers north of the Silver Peak benchmark. It is from a vertical dike, one of a series nearly in a line that cuts across the basement complex in a direction about north 75 degrees west, for a distance of nearly 2 miles. It is composed chiefly of green hornblende and may be desig- nated an hornblendite. The diorite dikes were supposed by Professor J. E. Clayton to be older than the quartz veins, but as they cut across the veins, this is evidently an error. They are more abundant near the quartz veins in which the silver values predominate, but they do not occur along all of the silver veins and are found along some of the gold veins. They do not appear, therefore, to have exerted any influence on the kind of ore found in the veins, and inasmuch as they are later than the veins, it is improbable that they have exerted any influence whatever on the ore deposition. PALEOZOIG SEDIMENTARY SERIES ALGONKIAN ROCKS Mr C. D. Walcott has established a lower limit for the Cambrian rocks, which if applied in this district will place some of the dolomites and quartzites of the Silver Peak quadrangle in the Algonkian. He writes:*® “At present I draw the basal line of the Cambrian in Utah and Nevada at the bottom of the arenaceous shale, carrying the Olenellus fauna. This refers the quartzite and siliceous shales of the Wasatch and similar sections, in- cluding that of the Eureka district, and that of the Highland range of Nevada to the Algonkian Period (Era).” On this basis the dolomite, quartzite, and the green knotted schists underlying the Olenellus zone north of the Clayton valley may be called Algonkian. This might apply as well to some of the quartzite and quartz-schist immediately west of the village of Silver Peak, and to the basal dolomite generally of Mineral ridge, as well to some similar rocks south of Cow camp. No fossils have been found in these basal dolomites and quartzites. On the geological map these basal beds are placed with the Lower Cambrian. They are referred to here more especially to call attention to the fact that the series underlies the fossiliferous Cambrian rather than to insist on the Algonkian age of the rocks, as it is quite possible that they represent the base of the Cambrian. THE PALEOZOIC BRA The Paleozoic fossiliferous rocks of the Silver Peak quadrangle are 1¢ American Journal of Science, vol. xxxvii, 1889, pp. 374-392. PALEOZOIC SEDIMENTARY SERIES 239 confined to the Cambrian and Ordovician periods. The Lower Cambrian beds are best seen in the northeast and southeast portions of the quad- rangle. They are, however, well exposed on Mineral ridge west and northwest of Silver Peak. The Upper Cambrian rocks, lying unconform- ably on the Lower Cambrian, are best seen in the north end of the Silver Peak range, near Emigrant pass. The Ordovician rocks appear to rest conformably on the Upper Cambrian, forming one series, but have been separated from them on account of the difference in age and lithological differences. ‘The Ordovician series is well developed in the Palmetto mountains. Except where there are intrusions of granolites, the Paleozoic rocks do not show much evidence of great disturbances before the period of uplift of the present ranges, which was probably near the close of the Tertiary era. LOWER CAMBRIAN The lowest Cambrian rocks are well seen in a remarkably fine section in the southeast portion of the quadrangle in Barrel Spring ravine, by the road from Silver Peak to Lida. From the mouth of the ravine up which the Lida road goes, at the north base of the hills to the south edge of the quadrangle, these rocks dip very evenly to the east of south at angles from 20 to 50 degrees, the average dip being in the neighborhood of 30 degrees. The lowest exposed beds are mica-slates and quartzites, with some limestone layers containing well preserved Olenellus of large size, more than one species of Archeocyathus, and other fossils, with a higher horizon of green slates and limestone beds also containing Olenel- lus'’ and in their upper portions little conical shells, probably Salterella. A still better section of the basal Cambrian beds is to be found in the hills north of Clayton valley. Here the base of the section is a dolomitic limestone and marble, perhaps 2,500 feet in thickness, overlain by massive quartzites and green knotted schists perhaps 4,000 feet in thickness. Neither the dolomite nor the quartzite contain any fossil remains, but underlie with apparent conformity the higher fossiliferous series. These beds have already been referred to as being possibly of Algonkian age. These knotted schists are seen under the microscope to be composed of minute colorless grains, probably both quartz and feldspar, with very abundant minute fibers nearly colorless, which seem to be sericite. The knots are in part chlorite and in part aggregates of opaque grains. There is a distinct schistosity, the dip being southwest at an angle of 30 degrees, and obscure traces of an original sedimentary structure dipping east 55 degrees. The bedding planes of the knotted schists are conformable 17 All of the Cambrian fossils from the Silver Peak quadrangle have been determined by C. D. Walcott. XXI—BULL. GEOL, Soc, AM., Vou. 20, 1908 240 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE with those of the banded limestone which immediately underlies a cal- careous layer containing Archeocyathus. This banded limestone, in which the sedimentation planes are indicated by alternating brown and dark layers one to three inches in thickness, dips 60 degrees to the east, and the sedimentation planes are cut by a schistose structure dipping southwest 10 degrees. The line of contact between the banded limestone and the schists is parallel to the bedding planes of the limestone, and this also suggests conformity. Calcite deposited along the planes of the schistosity brings out the schistose structure plainly. The overlying Archeocyathus limestone likewise shows planes of schistosity cutting the bedding planes. Overlying the basal Archeocyathus limestone is slate containing Kthmophyllum, and above this is green Olenellus slate. In the same _ section, overlying the green Olenellus slates, are thick layers of thin bedded limestone with thin bedded quartzites at the east edge of the quadrangle. In Mineral ridge, to the west and northwest of Silver Peak, the Lower Cambrian consists of Olenellus slates and dark fossiliferous limestone overlying massive dolomitic marble and quarizite. The Lower Cambrian series as a whole, considering its great age, shows remarkably little alteration, the massive limestones and quartzites fre- quently giving no evidence of crushing. As a result, the fossils are at most points well preserved. At some points, however, as north of Clayton valley, a schistose structure is developed, more especially with the Olenel- lus slates, and is often to be observed where there has been unusual crushing of the rocks. Several of the limestone layers are crowded with little orbicular bodies. These are not certainly of organic origin, but were not found in beds known to be of Upper Cambrian or Ordovician age. ‘ Analyses of carbonate Rocks of the Lower Cambrian George Steiger, Analyst Dolomite, | Dolomite, | Dolomite, | Limestone, number | number | number number 690. 468. 545. 563. gummi: Ss ee ee 8 ee eee 28.52 30.35 34.49 52.00 pu bid (Pec eves So ey a ee Se 19.19 20.19 11.38 .42 Perroussaxddlee ee cee es Co ee 95 1.89 | .....62ccfoeee ee : Carbon-ditexddes syns ee nae oe ae 44 09 AV.21 94....<22 0. eee Insoluble in boiling HCl. 1-3......... 7.18 OL. [noses i cee el en eet ———| i ll ae 99.93 99.95 Pe ees 18 Includes any Al; also any P,O, or TiO, that may be present. PALEOZOIC SEDIMENTARY SERIES QA1 Number 690 is the basal dolomite from the section north of Clayton valley. Number 468 is a dolomitic marble taken at the contact with the white gran- ite of Mineral ridge, 6.3 kilometers west of north from Red mountain. Number 545 is a dolomitic marble from near the white granite of Mineral ridge, 6.6 kilometers northeast of Red mountain. Number 563 is Lower Cambrian limestone from the Silver Peak range, con- taining an abundance of little orbicules. The isolated areas in the extreme northeast part of the quadrangle, to the south of Lone mountain, are probably Lower Cambrian, but no fossils were found in them. ‘The rocks of these areas are for the most part highly metamorphosed by the granite of the Lone Mountain mass, the. limestone being converted into marble and the argillaceous rocks into schists. _ The larger portion of the higher parts of the Silver Peak range, from a point about 2 miles south of Emigrant pass to Red mountain, is made up of Lower Cambrian slates and limestones. he slates and some associated quartzites are green in color, and the microscope shows that this color is due to abundantly disseminated chlorite. The Lower Cambrian area to the north of the Emigrant road, at the west base of the range, consists at the base of, green schists containing little conical shells. Overlying the schists are limestone layers full of little orbicules. The Lower Cambrian limestone is crushed and faulted to a remarkable degree, while the overlying thin bedded limestone of Upper Cambrian age lies quite regularly at some points on this Lower Cambrian foundation, some reddish and green slate intervening at other points. The dip of the Lower Cambrian series varies. At some points it is northeast 45 degrees and at other points southeast 10 to 40 degrees. The overlying Upper Cambrian rocks in this vicinity dip rather regularly to the southeast at angles from 5 to 10 degrees. The Lower Cambrian rocks of Mineral ridge have largely been eroded, but two higher ridges with a north-south trend remain as a capping to the pre-Cambrian complex. The small areas of Lower Cambrian rocks, represented as capping the pre-Cambrian at various points on Mineral ridge, and especially along the east base, are composed mostly of buff dolomitic marble, which is possibly of Algonkian age, as are also some quartzite masses just west of the village of Silver Peak. The areas of supposed Cambrian rocks at the west base of the Silver Peak range, south of the Silver Peak-Fish Lake road, are mostly schistose rocks in which no fossils were found. Their age is therefore a matter of doubt. At one or two points in these areas are small masses of old igneous rocks, one of which is, perhaps, a metamorphic basalt. The areas to the north of Piper peak are also largely schist, somewhat resembling 242 H. Ww. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE the knotted schist described in the section north of Clayton valley. In these rocks also no fossils were found. ‘To the southeast of Cow Camp springs are several areas composed of mica-schist, red and green slate, with some quartzite and red marble. These areas afforded no fossils. The section along Barrel Spring ravine has already been referred to. It abounds in fossils and is intruded at numerous points by dikes of acid metamorphic lavas. A rough measurement of this series of beds along Barrel Spring ravine placed the thickness at over 10,000 feet. Alcatraz island and Goat island, in the Silver Peak marsh, are made up of Olenellus slates and limestone. UPPER CAMBRIAN The Upper Cambrian is present in several portions of the quadrangle. It consists at the base at some points of a red limestone breccia resting with a distinct unconformity on the Lower Cambrian, as in the group of hills lying 4 miles immediately east of Silver Peak village and at the west side of the north part of the Silver Peak range 4 miles north- east of the mill of the Pacific Borax Company, in Fish Lake valley. Overlying the breccia are successively layers of thin bedded siliceous argillite, thin gray slate showing faint impressions of graptolite remains, brown slates, heavy beds of thin bedded dark limestone, red and brown slate containing well preserved minute disk-shaped shells (linguloids), some trilobites (Acrotreta), abundant fragments of Phyllocarida, and some corals. This series is best developed in the vicinity of Emigrant pass, espe- cially to the south of the Emigrant road, on the west side of the range. The shells are well preserved and are regarded by C. D. Walcott as indi- cating an Upper Cambrian age. The beds appear to conformably under- lie the siliceous argillite and slate of the Ordovician, which is chiefly characterized by graptolite remains. Moreover, the Phyllocarida, so common in the Upper Cambrian, are found in layers interbedded with the graptolite slates at the base of the Ordovician, and the linguloids of the Upper Cambrian were found in slates but a few feet under the gray graptolite slate, with no evident unconformity between. While the Upper Cambrian rocks were found in nearly all parts of the quadrangle, they are nowhere so rich in fossils as to the south of the ‘Emigrant road. In nearly all areas the thin bedded limestone forms a conspicuous feature. In the area 5 miles east of B. M. 4996 no fossils whatever were found, and this mass is assigned to the Upper Cambrian largely because of its conformable position below the Ordovician siliceous argillite. PALEOZOIC SEDIMENTARY SERIES 243 The Upper Cambrian beds in the Silver Peak range dip usually to the northeast. In the area 5 miles east of B. M. 4996 they dip easterly, and in the area just east of the Clayton marsh they dip northwest. THE ORDOVICIAN SEDIMENTS Overlying the Upper Cambrian rocks are thin, black, gray and red slates interbedded with layers of black siliceous argillite and sandstone. The slates contain at a great number of points very abundant graptolites. As noted under the Upper Cambrian, there appears to have been a con- tinuous deposition of sediment from Upper Cambrian time to the Tren- ton horizon of the Ordovician. | The collections of graptolites were examined by Mr Charles Schuchert, who states that there are two horizons represented—one the Normanskill or lower Trentonian, and the other the Quebec horizon. Nearly all of the graptolites, however, belong to the Normanskill zone. In the Quebec horizon Mr Schuchert found two characteristic genera, Didymograptus and Tetragraptus. In the Palmetto mountains and at some other points there are very numerous streaks of light colored felsitic rocks interbedded with the dark siliceous argillite of the Normanskill zone. The microscope shows that the felsitic layers are chiefly old rhyolitic or dacitic lavas and tuffs. It is thus certain that in Ordovician time there were volcanic eruptions in the region. Certain other light colored felsitic-looking layers are in part metamorphosed into garnet, pyroxene, and calcite and epidote. Nearly all the north end of the Silver Peak range is composed, where not covered with rhyolite, of the cherts and slates of the Ordovician, containing at several points recognizable graptolites. At many places these beds are highly contorted and faulted and dip in various directions at high angles, the general strike, however, being nearly east and west. At some localities they are intersected by veins of calcite, but no quartz veins were noted in them. In the neighborhood of the Emigrant pass, both to the north and south of the Emigrant road, graptolites may be found in the rocks at many points. In nearly all of this district the beds dip in an easterly direction. TERTIARY SEDIMENTARY SERIES ESMERALDA FORMATION General character—tIn the central and northern part of the quad- rangle there are beds of light colored marls, slates, and sandstone which were laid down in the waters of a lake. They are designated the “Esme- 244 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE ralda formation,” after the county in which they occur. There are local developments of sedimentary breccias probably of subaerial origin and conglomerates on a large scale. The lake beds contain the remains of fresh-water mollusks and fish, which indicate that the water of the lake must have been fresh or only slightly saline. In addition, there are very abundant plant remains and beds of coal. Inasmuch as Professor Knowlton has described the fossil plants in detail elsewhere,’® they will be only briefly referred to here. The flora is represented by ferns, the fig, oak, willow, sumach, and soapberry, and includes tree trunks 6 to 8 feet in diameter, showing that the climate has undergone a great change since Tertiary time. From a well watered region it has become an arid one in which there are no running streams. The first published notice of these Tertiary lake beds appears to be that of M. A. Knapp, describing particularly the coal deposits*® occurring in the beds at the north end of the Silver Peak range. Mr Knapp col- lected some molluscan remains near the coal beds, and these were ex- amined by Dr J. C. Merriam, of the University of California, who considered the shells indicative of fresh water and possibly Miocene in age. Areal distribution of the beds——On the geological map in Spurr’s report the areas of the Esmeralda formation are shown as “Tertiary stratified rocks.” In the southern part of the quadrangle the beds are visible at only a few points and are undoubtedly mostly wanting, for there are older rocks at the surface nearly everywhere in the Palmetto mountains and the southern part of the Silver Peak range. The lake beds undoubtedly underlie the later deposits of Clayton valley, of the southern part of Big Smoky valley, and of the northern part of Fish Lake valley. They are also reported to have been struck in a well bored at Columbus, at the west side of the valley of that name, which lies just north of Silver Peak range. It is probable that they underlie the Columbus marsh. They certainly extend north of the Silver Peak quadrangle into Big Smoky valley. As far as present evidence goes, within the limits of the Silver Peak region the basin containing lake Esmeralda was bounded on the south by the Palmetto mountains at the south end of Clayton valley, on the east by the Montezuma mountains, 19H. W. Turner: ‘The Esmeralda formation, a fresh-water lake deposit,’’ with de- scription of the fossil plants by F. H. Knowlton and a fossil fish by F. A. Lueas. Twenty-first Annual Report of the U. S. Geological Survey, part 2, pp. 192-224. 2 The coal fields of Esmeralda county, Nevada. Mining and Scientific Press, San Francisco, vol. Ixxiv, 1897, p. 133. ; It might be noted, however, that fossil fishes from this formation were collected pre- _ viously by J. E. Clayton and W. P. Blake, but no description of these fossils appears to be in print. Proceedings of California Academy of Science, vol. iii, 1866, p. 306. TERTIARY SEDIMENTARY SERIES 245 and on the west by the Inyo range, the northern limit being entirely unknown. Moreover, this basin may easily have connected through the depression north of Lone mountains with the Ralston Desert basin, which lies east of the Montezuma mountains. The beds arch up over the central part of Silver Peak range, reaching an altitude of 7,000 feet at Red mountain. It is therefore clear that this portion of the range did not exist in Tertiary time, and that its site was a portion of the lake basin extending from the Inyo range on the west to the Montezuma mountains on the east. It is also clear that this portion of the range was uplifted in post-Esmeralda time. The highest part of the Silver Peak range at- tains an altitude of 9,500 feet, but the highest summits are made up of | Tertiary lavas of later age than the lake beds. Basal conglomerate of the Esmeralda formation.—In the upper por- tion of Ice House canyon and in the ridges to the west are narrow lenses of conglomerate, often of a bright red color, containing very abundant > subangular but evidently waterworn fragments of green schist, blue lime- stone, marble, vein-quartz, and fragments of black siliceous argillite. The green schist or slate is apparently precisely like that found in the Lower Cambrian, and the siliceous argillite is indistinguishable from the siliceous argillite of the Ordovician. These fragments are imbedded in a limestone matrix, and in this matrix there are frequently oval bodies, with a maximum diameter of 114 inches, which show in section a distinct concentrically laminated structure. These bodies, like the orbicules pre- viously mentioned of the Lower Cambrian limestone, have been examined by several paleontologists, who regard them as of concretionary origin. The conglomerate lies with a marked unconformity on the Paleozoic rocks. Immediately overlying the conglomerate lenses, which are perhaps 100 feet in maximum thickness, are basalts and other lavas. Similar beds are found at the base of the Esmeralda formation, in the central part of the Silver Peak range, 3 miles northwest of the summit of Rhyo- lite ridge, at the head of a large ravine. Overlying the conglomerate are hardened buff sandstones. Tertiary detrital-slope breccias——The low, dark hills and ridges east and southeast of the south end of the Big Smoky valley are covered with loose fragments of Cambrian and Ordovician limestone, quartzite, and slate. A careful examination of these hills shows that they are made up of coarse bedded breccias, intercalated with thin sandstone layers. The beds dip at considerable angles, and farther southeast, apparently con- formably overlying the breccias, are fine sediments containing fish re- mains. The breccias evidently represent old detrital beds of subaerial origin, and would seem to indicate oscillations of level of the waters of lake Esmeralda or local uplifts and depressions. 246 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE Conglomerate beds——The extensive conglomerate beds 4 miles north- east of the Monocline show the action of moving water, and hence are possibly of fluviatile origin. The Tertiary period in this region being a time of extensive volcanic activity, the outlines of the lake must have undergone frequent changes, and undoubtedly there were local upheavals and subsidences during the lake period. The coarseness of the volcanic sediments are, however, no evidence as to a shallow-water origin, since the ashes would be thrown out from volcanoes all over the lake and form coarse deposits even in deep water, where under normal conditions only fine sediments would be deposited. Thickness of the beds——No continuous section of the entire formation was found, but an attempt was made to estimate the approximate thick- ness of the beds. They dip nearly everywhere at angles varying from 5 to 60 degrees from the horizontal and are broken by numerous small faults, so that often a layer followed along the strike is found to offset from 10 to 100 feet or more every few hundred feet. However, the lake sediments are finely exposed in the large area east of the north end of the Silver Peak range and in a northwest-southeast section constructed here across the strike of the beds. No evidence was noted of a repetition by faulting or folding, and if there is no repetition the series must have a total thickness of over 10,000 feet. Detailed evidence as to this section and other information concerning the Esme- ralda formation will be found in the paper before referred to in the Twenty-first Annual Report of the U. 8. Geological Survey. NEOCENE RIVER GRAVELS Outside of the gravels of the Esmeralda formation, there are in the southern part of the quadrangle masses of well rounded gravel which have no established connection with the lake beds. They presumably are river deposits from streams that existed at the same time as lake Esme- ralda. One of the masses lies 414 miles south of Cow Camp spring, east of the road to Oasis; it is capped by basalt. The pebbles are well water-worn and are of granite, slate, and lava. Another lies 414 miles southwest of Piper peak. The pebbles of this area are many of them several inches in diameter. The deposit rests on supposed Ordovician rocks, next to an area of rhyolite. Scattered pebbles are also found on the crest of the Palmetto mountains about little patches of basalt, suggesting that they are remnants of a river deposit once covered by basalt. A large area of gravel and sand lies about 5 miles north of west from Piper peak and QUATERNARY DEPOSITS 247 is composed of comparatively small pebbles of a granitic rock (quartz- monzonite) and of a siliceous argillite like that of the Ordovician. It is capped by basalt and at one point lies on a bed of pumice with a second pumice layer, about 3 feet thick, intercalated in the gravels near the top of the series. The entire thickness of the formation is here over 200 feet and the beds are disturbed, dipping at some points 10 degrees or more easterly; at some places they are faulted. Exactly similar gravel is found — the pumice at the west end of the Piper Peak ridge. ete QUATERNARY DEPOSITs. DESERT DETRITUS There is nothing so striking in the Great Basin region as the numerous detrital slopes, which spread out from all the canyons and fill consider- able portions of the valleys. In view of the very small precipitation in this region, the formation of these numerous fans would seem to involve a very long period of time. They are composed chiefly of coarse material, often containing boulders tons in weight. When the older detrital material is cut by the present watercourses or “washes,” the stratified arrangement of these materials is clearly evident. There can be no doubt that their distribution is due to the action of water. A consideration of the manner in which rain falls in all this desert country suffices to ex- plain the formation of these detrital slopes, for although the precipitation is very small when the region as a whole is considered, it is often very great within the space of a few hours over a limited number of square miles. The action of the sun and the frost on the rocks of this dry region results in the surface rocks being everywhere extensively cracked, and the fragments, although about in their original position, are easily dis- placed. When a cloudburst occurs the rain runs off in torrents and sweeps before it large quantities of this loose material, and when the cloudbursts are of sufficient size they will carry boulders many tons in weight far out on the plains. There is therefore no difficulty in account- ing for the formation of the alluvial fans, but the time that must be allotted to their formation, if we suppose the precipitation to have been no more in the early Pleistocene than at present, would be enormous. It is quite certain, however, that in earlier Pleistocene time the precipi- tation was much greater than at present. It is probable, therefore, that the larger part of these detrital slopes was formed during the first half of the Pleistocene. This would harmonize with the record in the Sierra Nevada. The larger part of Pleistocene time was required for the exca- vation of the canyons. This early Pleistocene period of erosion has been 248 H. w. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE termed the Sierran** period, and the larger detrital slopes of the Great Basin is referable to this period. The older detrital materials have undergone uplift at many oe The hills just north of the Cave Spring road and just east of Fish Lake valley are largely Pleistocene conglomerates overlying the Esmeralda formation. ‘This conglomerate is somewhat consolidated and dips north- erly at angles of 10 to 35 degrees. There may be observed in it a white layer composed of carbonate of lime. This is seen in the east face of the first hill north of the Cave Spring road, and also on the north face of the hill 4 miles northeast of the Crossing. To the south of the Cave Spring road there are heavy beds of gravels and detritus, possibly formed at the same time as the Pleistocene conglomerate, north of the road. The beds to the south of the road are not tilted, but have undergone elevation, _ forming a striking terrace (plate 8) facing Fish Lake valley. The recent “washes” in this terrace show a thickness at one point of 250 feet of detritus and gravel containing some boulders six feet in diameter. There are many gravel patches mixed with angular detritus on the north slope of the Palmetto mountains and of the Silver Peak range east of the road from Silver Peak to Oasis. The altitude of these masses is approximately 6,500 feet, but they have a vertical range of several hun- dred feet, probably due to these loose materials creeping down the slopes. There is not much doubt, however, of their Pleistocene age, as they in part distinctly overlie Tertiary lavas. The pebbles in these masses are composed of granite, slate, and lava. Mr J. E. Spurr has noted in other ranges of mountains in western Nevada bodies of gravel, often at an elevation of 6,000 feet, which may be of the same character as those here referred to. The gravels seen by Mr Spurr are thought by him to be shore gravels formed by lakes contemporaneous with the Pliocene Sho- shone lake of the Fortieth Parallel region described by Clarence King. The evidence as to the origin of these gravels in the Silver Peak region is too meager to warrant any conclusion further than they are probably Pleistocene. In general it may be said that the rocks of the Pleistocene detrital . masses are usually the same in kind as the rocks of the present drainage above them, indicating a local origin. When the older detritus is fine grained, and where it is largely volcanic, it is sometimes difficult to dis- tinguish it from the ordinary sediments or voleanic sandstones of the Esmeralda formation. Resting on the lavas north and northeast of Piper peak, at an elevation of about 8,000 feet, there are some remarkable 21 Proceedings of California Academy of Science, third series, Geology, vol. 1, p. 269. The term was introduced by O. H. Hershey. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 8 TERRACE OF EARLY PLEISTOCENE DETRITUS EAST OF FISH LAKE VALLEY QUATERNARY DEPOSITS 249 terraces composed of coarse subangular lava detritus. :These appear to be referable to the early Pleistocene. TRAVERTINE OR CALCAREOUS SPRING DEPOSITS _ There are noted on the geological map, at the south end of the Clayton Valley playa and at other points, small masses of travertine, presumably formed largely in recent time. Some of them are, however, so inter- bedded with sandstones of the Esmeralda formation—for example, the mass one mile west of Cave spring—as to suggest a contemporaneous origin with the inclosing sandstone, and such masses may be of Tertiary age. PLAYA DEPOSITS The playa deposits comprise two areas in Fish Lake valley, one in Clayton valley, and one in Big Smoky valley, locally known as the San Antonio marsh. All of the playas in Fish Lake valley within the quad- rangle contain borax salts and have been worked for borax. Over many square miles the Big Smoky playa shows a thin white coating which consists largely of chloride of sodium. Over other portions of the valleys are deposits of other salts, such as sulphate of soda, which are ordinarily termed alkali. SAND DUNES At the south end of Clayton valley is a considerable group of hills composed entirely of wind-blown sand. This is said to contain a small amount of gold distributed through it. These dunes appear to have been formed by an eddy in the air currents, which seems permanently to exist at this point. They shift about from year to year to a certain extent, but on the whole remain essentially at their present location. There are also low hillocks of sand near the San Antonio marsh in Big Smoky valley and in Fish Lake valley. RECENT DETRITAL FANS The latest of the alluvial fans, formed largely by the rearrangement of the materials of older fans, undoubtedly belong to Recent time. GRANULAR IGNEOUS RocKS GRANITE AND SYENITE Under this heading are described granitic rocks which are much later in age than the granites and gneisses of the pre-Cambrian complex. The granite and syenite series comprises granolites nearly all of which are rich in alkali-feldspar. | 250 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE The granite rocks of the northeast portion of the quadrangle, north of Clayton valley, are chiefly true granites and granite-porphyry, but there are here also some granite-gneisses. These rocks are composed of alkali- feldspar and quartz, with some biotite and muscovite. The alkali- feldspar varies in its character at different points—orthoclase, microcline, micropegmatite, microperthite, and albite having been detected in the specimens collected. The south base of Lone mountain, the summit of which is not on the quadrangle, is made up of a coarse, light gray biotite-granite-gneiss con- taining orthoclase, microcline, micropegmatite, oligoclase, quartz, biotite, iron-oxide, titanite, and apatite. The isolated butte in the detritus lying about three-fifths of a mile south of the south base of Lone mountain is composed of an even grained granite of fine texture containing quartz, microcline, micropegmatite, and orthoclase with a little oligoclase, mus- covite, and chlorite. The large area north of Weepah, 6 miles in diame- ter, is in part a granite-porphyry composed of phenocrysts of orthoclase, oligoclase, quartz, and biotite in a microgranular quartz-feldspar ground- mass which contains a little iron oxide, apatite, and zircon, but some of the specimens collected from this area are evenly granular rocks with egneissic structure locally developed, composed of orthoclase, microcline, albite, and quartz with a little muscovite, biotite, iron oxide, and apatite. The quartz occurs in aggregates of interlocking grains of smaller size than the feldspar grains. In the southwest portion of this area there are also true granite-gneisses. The small area that lies 344 miles northeast of the Clayton Valley crater is composed chiefly of a coarse biotite-granite, but the northwest portion of the mass is a white medium grained quartzite-like rock which the microscope shows to be chiefly quartz and albite or soda-feldspar. QUARTZ-MONZONITE Granitic rocks in which the alkali and soda-lime feldspars are both pres- ent in abundance are here termed quartz-monzonite. Rocks of this type are very common in the southern portion of the quadrangle. The two large areas, shown on the map in Spurr’s report, in the southern part of the Silver Peak range and as extending thence southeast to the Palmetto mountains, differ from the granolites of the other portions of the quad- rangle in containing more plagioclase and biotite, and are therefore better designated by the term quartz-monzonite. They may be differentiated into two types—a coarse variety, often with porphyritic feldspars, and a medium, even-grained variety. The coarse rock forms the larger part of these two areas and is probably the older rock. This type is of rather GRANULAR IGNEOUS ROCKS 951 even texture with only small porphyritic crystals in the largest area, which forms the crest of the western part of the Palmetto mountains and of the southern part of the Silver Peak range, but in the smaller area, east of Fish Lake valley, on the western flanks of the Silver Peak range, there are developed porphyritic orthoclase crystals often an inch or more in length. The area 5 miles northwest of Piper peak is also of this character. The second type of quartz-monzonite is a medium, even-grained rock forming at some points considerable masses, the largest one noted being on the north side of the Palmetto mountains. It is probably later in age than the coarse type. The two types of quartz-monzonite just noted as occurring in the Silver Peak range form the foothills of the Inyo range, in the extreme southwest corner of the quadrangle, the coarse type here having large porphyritic crystals of orthoclase. The medium grained quartz-monzonite is present here in smaller amount and is distinctly later in age, as it contains blocks of the coarse porphyritic variety. In the table of analyses the chemical composition of some of these rocks is indicated. It will be noted that numbers 348, 349, and 653 are true granites, but these appear to be merely facies of the quartz-mon- zonite magna. Partial Analyses of Quartze-monzonite and Granite from the southern Part of Silver Peak Range George Steiger, Analyst Quartz- set bie . . Soda- monzonite, Granite, | Granite, Granite, granite aber number | number |} number in ; 664. 653. PAS an Nile peeey 324. 349. SLICE 5 6 a tle Aelee 69.23 Alle 68.50 (ore, 76.04 LRG, Og 5 ee 3.38 2.56 .60 52 .46 ib de of dea De ee 3.75 3.65 4.05 2.79 7.58 LORI. ee 4.75 aon 4.83 5.35 .07 Description of the Rocks Analyzed Quartz-monzonite, specimen number 324.—Locality: In the Palmetto moun- tains, 10.2 kilometers southwest of Barrel spring. Macroscopically, a light gray coarse grained granitic rock, apparently chiefly feldspar. Microscopically, a coarse grained monzonite in which the orthoclase exceeds the plagioclase in amount. Feldspar, quartz, pyroxene, and accessories. Granite, specimen number 664.—Locality: On the east side of Fish Lake valley, 20.7 kilometers southwest of Piper peak. Macroscopically, a fine grained light gray granite. Microscopically, an evenly granular rock composed of microcline and micropegmatite, plagioclase, quartz, biotite, epidote, and titanite. 252 H.W.TURNER GEOLOGY OF THE SILVER PEAK QUADRANGLE Granite-porphyry, specimen number 653.—Locality: Silver Peak range, 10.3 kilometers south of Piper peak. : Macroscopically, a dark gray fine grained porphyry. Microscopically, a por- phyry with a micro-granular spherulitic groundmass of quartz and feldspar in which are imbedded crystals of plagioclase, orthoclase, quartz, biotite and iron ore. Granite, specimen number 348.—Locality : North slope of the Palmetto moun- tains, 8 kilometers south of west from Barrel spring. Macroscopically, a fine, even grained granolite composed of feldspar and quartz with some biotite. Microscopically, the feldspar, quartz, biotite, iron oxide, and apatite. The feldspar is both plagioclase (oligoclase) and ortho- clase, the former showing an idiomorphic tendency. Soda-granite, specimen number 349.—Locality : Same area as number 348, in the Palmetto mountains 8 kilometers south of west from Barrel spring. Macroscopically, a nearly white fine grained granite. Microscopically, a soda-granite made up of feldspar quartz, biotite, and titanite. The feldspar is chiefly albite and oligoclase. QUARTZ-DIORITE The dioritic areas in or near the granite area north of Weepah contain at some points quartz and may be designated as quartz-diorite. Some of the rocks of these areas contain biotite, titanite, magnetite, and apatite. In one specimen the feldspar is labradorite in lath forms with later inter- stitial amphibole, forming an amphibole-diabase, but this appears to be merely a facies of the diorite. GRANULAR DIKE ROCKS These have already been briefly described under the head of “pre- Cambrian complex” as certain greenstone dikes that cut all the other members of the complex. Sometimes these dike rocks are softer than the surrounding granite, gneiss, and schist, and their courses are then indi- cated by troughs, as the large dike 1.5 miles north of Silver Peak. This is probably the trap dike referred to by Lieutenant Lyle in his travels through this region in 1871.22 These dikes are composed chiefly of plagioclase and green-brown hornblende and may in general be designated basic diorite. In true diorites, however, the feldspar is oligoclase and andesine, while in some of these dikes it is in part labradorite. By loss of feldspar and increase of hornblende, some of the greenstone dikes of the pre-Cambrian complex pass into hornblendite. An example of this is" the large east-west dike before referred to, 1.5 miles north of Silver Peak. The dioritic dikes in the Silver Peak formation to the south of the diorite areas above referred to, in the northeast portion of the quadrangle, contain as their most abundant constituent plagioclase. The amphibole 22 xploration in Nevada and Arizona. War Department, Washington, 1871, p. 49. VOLCANIC ROCKS 258 is usually in the form of needles, and there is sometimes pyroxene present, as well as biotite and ilmenite. Diorite dikes are very abundant in the southern flanks of the Silver Peak range, both in the Ordovician sediments and in the large areas of quartz-monzonite. Many of these dikes are indicated on the geological map in Spurr’s report. They appear to be normal diorites. The amphi- bole is often in the form of needles, and the feldspar in the form of laths. There is biotite present and secondary epidote. ‘There are some diorite _ dikes in the Palmetto mountains, and very abundant diorite dikes in the slates and limestones 5 miles west of south from Piper peak. VoLcANIc Rocks AGE The lavas of the Silver Peak quadrangle may be divided into an older series, associated with Paleozoic rocks and probably Paleozoic in age, and a later series, of Tertiary age. The Paleozoic lavas are usually much altered, which condition is expressed by the prefix meta. Thus there are fresh rhyolites in the Tertiary and meta-rhyolites in the Paleozoic. META-RHYOLITE Rhyolitic lavas which have undergone alteration are designated meta- rhyolite. In such lavas the original glassy groundmass has become more or less crystalline. Such a groundmass originally glassy is sometimes called a devitrified groundmass. The devitrified dacites or meta-dacites are here placed with the meta-rhyolites. All of the rocks grouped under the head of meta-rhyolite are presumed to be pre-Tertiary in age, and most of them are known to be of Ordovician or Cambrian age. The meta- rhyolites, so far as known, are the oldest lavas of the Silver Peak quadrangle. They form bands or lenses in Paleozoic sediments most abundantly in the Palmetto mountains, but are found in all parts of the quadrangle. No analyses were made of the lavas except from dikes. Many of these dikes are completely crystalline, and analyses of three of them indicate a high content of soda. The examination of the thin- sections of the dike rocks shows that some of them contain little or no quartz, as, for example, numbers 319 and 343 of the table of analyses. Soda-rich, completely crystalline igneous rocks may be called micro-soda- syenite or keratophyre. Number 319 evidently has the composition of an alkali-rich andesite or latite and number 343 of a quartz-keratophyre or soda-rhyolite. Other dikes are fine grained and evenly granular, and 254 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE to such completely crystalline rhyolitic lavas the term micro-granite is sometimes applied. Some of the meta-rhyolites contain microperthite. There is thus a considerable variety of rocks, especially dike rocks, included on the geo- logical map under the term meta-rhyolite. Partial Analyses of Soda Meta-latite, Meta-rhyolite and Keratophyre George Steiger, Analyst Number | Number | Number 319. 343. oie: Side cc ase S Aas we a oo Seen clas AOS oR eee 56.34 68.40 80.60 Teme: 2 2.4 eee Se re ee ieee 4.0L 2.83 18 OG eee die een ee ee eel wee ee 6.32 9.00 6.04 PO tashincss Sean aie oe ae ee ee ec eee 2.63 none none Felsitiec rock, specimen number 319.—Locality: In the Palmetto mountains, 11.7 kilometers southwest of Barrel spring. Macroscopically, a fine grained flinty rock, slightly brownish in color. Microscopically, a felsitic rock of undetermined composition, filled with sec- ondary products. The chemical composition is that of an alkali-rich andesite or latite. Soda-syenite-porphyry or keratophyre, specimen number 343.—Loeality: Dike in the Ordovician cherts of the Palmetto mountains, 5.5 kilometers southwest of Barrel spring. Macroscopically, a light colored, slightly brownish rock showing porphyritice feldspars. Microscopically, a porphyritie rock with a micro-granular quartz- feldspar groundmass in which are prisms of albite and oligoclase. Monoclinic pyroxene is rather abundant, and there is a secondary mineral, apparently epidote, present. Soda-meta-rhyolite or quartz-keratophyre, specimen number 313.—Locality: Dike in Lower Cambrian rocks, 2.6 kilometers southeast of Barrel spring. Macroscopically, a nearly white, fine grained, apparently holocrystalline rock. Microscopically, a porphyritic rock with a micro-granular quartz-albite groundmass crowded with spherulites and phenocrysts of quartz and albite. The Tertiary lavas are grouped under the general names basalt, andesite, and rhyolite. ‘There is, however, considerable variety in the rocks included under these names, as will be indicated in the special descriptions. RHYOLITE AND DACITE Under this head are included all the acid lavas, rhyolites, and dacites, which when sufficiently crystalline usually contain free silica or quartz and a variable amount of sanidine. There are large areas of rhyolite VOLCANIC ROCKS 255 in all parts of the quadrangle, mostly in the form of tuff or volcanic ashes. As a rule, the tuffs are arranged in layers, like sedimentary rocks, but where masses attain a great thickness, as near Hmigrant peak, strati- fication is not always to be observed. More often than otherwise the rhyolites of the quadrangle are largely made up of volcanic glass partly in the porous form known as pumice. At some points the magma became almost completely crystalline, as with number 93 of the table of analyses. At other points, to the south of Red mountain, the rhyolite crystallized in little spherulites in which are imbedded crystals of sanidine, quartz, brown biotite, and other minerals. The rhyolite of the upper part of Red mountain is red in color and shows flow structure beautifully. It is mostly devitrified and might appropriately be called meta-rhyolite. For the purpose of distinction, however, that term will here be used only for pre-Tertiary rhyolite. The rhyolite shown at various points on the map near basalt areas is usually pumice, and the frequent association of the two lavas, basalt and pumice, suggests that perhaps both came from the same magma, the lower specific gravity of the rhyolite pumice causing it to separate from the heavier basalt. Dacites or acid quartz-andesites are not present in large amount. ‘They form in the rhyolite tuffs layers which are conspicuous by reason of their darker color, and are upon nearer inspection found to be made up largely of a dark glass rich in biotite. ‘These layers are usually less than 50 feet in thickness and seem to occur at a rather definite horizon in the tuffs, as if erupted at about the same period. One of these layers may be seen along the road east of Cave spring and others in the rhyolite tuffs southeast of Piper peak. There are beds of pumice in the con- glomerate of the Esmeralda formation east of the south end of Big Smoky valley and in the gravels assigned to the same formation north of the west end of Piper Peak ridge. There are beds of rhyolite sandstone overlying the marls east of the Clayton Valley playa. ‘These sandstones, although in places they are composed nearly entirely of rhyolite material, are placed in the Esme- ralda formation, and this is likewise the case with similar beds in the north end of Fish Lake valley. XXTII—Butu. Grou. Soc. Am., Vou. 20, 1908 256° H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE Analyses of rhyolitie lavas George Steiger, Analyst Tuff, | Dacite, poets Rhyolite- number | number bere granophyre, 3006. 53. Sire number 93. | 506. SIOss Soke nite ne ere eee 64.78 69.76 72.54 75.93 TiOpiin Sn ods De ae Ee eee 0.19 0.35 4... ee p20 © atareer ume riirarr te ie cin POS See ell aca el 5S cle 14.05 13.32. jo). eee den @ aneurin ne apa nte See SOURCE, 2 LRT Fe. none none 0.09 22.2 PEO Sh hea i aaa is ie eee me en 2.05 241 | .ceaeee MS Oie stay tat auc ut eee ee ee 0.17 0.51 |.4 eee CAO rs tne AE eT olan coer ee 2.07 ila iiase 17Se 1.37 NaS O) 4 oe bees) io Re oe ee ee ee 3.42 3.90 3.40 2.80 | G0) eats Meta tars t AaaENT en 5) SD oe a Ss 9.13 3597 5.25 4.49 1 U0 neem nae ATES rs act nis NSIS Wnty a So 0.62 0:21 <|.. 22a mS SE Ee ee Pe Sere Sais She 3.65 - . a eee LO). ode reece ce ot be dae sees ewsee oac@ulect ene e cles «se. a] 5 Ost n—n COs Es Be ee none nohe |. >] aes Pesan us (cu) agate Ee eee 0.07 0.11... |. 22a Min OMe ess oh ain eee ea OES ere ee ee 0.10 none’). : 2. eee BaQney Sao whe es OR aan eee eee 0.14 0.03: |... eee BP sae 1v0.00 100.62: . J: eee Tuff number 336 came from a rhyolite-tuff area. The rock is composed of particles of compaet rhyolite, pumice, feldspar, quartz, and dark microlitic lava fragments, apparently andesite. These andesitic fragments undoubtedly account for the chemical composition as given in the partial) analysis, which shows too much lime and too little silica for a typical rhyolite. Dacite number 53 is a black glassy lava in which are imbedded phenocrysts of plagioclase, sanidine, and possibly some quartz, but no positive uniaxial figure was obtained. The plagioclase is both albite and labradorite. There are abundant phenocrysts of biotite and some of hornblende and augite. Mag- netite and apatite are present. Spherulitic rhyolite number 506 is from 3.9 kilometers southeast of Red mountain. It is composed of radial spherulites which have an index of re- fraction less than that of the balsam, and hence probably are made up chiefly of orthoclase. In this spherulitic groundmass are imbedded erystals of sani- dine, quartz, reddish brown biotite, a little amphibole, and a little plagioclase, apparently oligoclase. There are numerous prisms of titanite, some of which is pleochroic in greenish colors. There are grains of magnetite, and zircon must be present, as it is indicated by the chemical analysis. Rhyolite-granophyre number 93 is from 3.6 kilometers northeast of Emi- grant peak. It shows a microgranular groundmass largely feldspathic, in which are imbedded abundant phenocrysts of quartz which are sometimes idiomorphic, sometimes much corroded, angular sanidines not corroded, and a — little biotite. 23 Includes any SrO. VOLCANIC ROCKS DAS The rhyolitic areas about the north end of Fish Lake valley contain much pumice and perlite, and rounded fragments of black obsidian. These fragments appear to owe their rounded form to having been blown into the air from the volcano while cooling. ‘There are dark brown layers of dacite in these rhyolitic areas and more or less rhyolitic sand- stone. Rhyolite ridge is a very picturesque accumulation of rhyolitic sand- stones and tuffs with one or more layers of darker dacite. The sandstones and tuffs are very regularly bedded, dipping to the west usually at low angles. The rocks are mostly of a light buff color, with some red layers, the stratification being magnificently shown on the nearly perpendicular bluffs of the east side. ANDESITE Andesite forms large areas in the quadrangle, chiefly in the form of breccias or tuffs. Such is the andesite of the north foothills of the Palmetto mountains, those about Cow camp, and elsewhere. There are, however, massive lavas of coarse grain, which are here placed with the andesites because of the difficulty of separating these rocks from true andesites in the field. ‘These massive lavas differ mineralogically from andesites proper in containing orthoclase in the groundmass. Their chemical composition is indicated by analysis number 27. It will be seen that this rock is low in hme and rich in potash when compared with a typical andesite. The large andesite area northeast of Piper Peak basalt area contains much of this alkali-rich type, which approximates in com- position to the latites of Dr F. L. Ransome.** Partial Analysis of Latite-granophyre, Number 27 George Steiger, Analyst SUI MMPI ete eteey ewes Meee e wide. ein thet ace Fo PRO die we coe ee es 64.28 LLINSIYS |p yee ne ie ARUN ERE RO eg ie mC es ee ee en ee a Syn (C8) SSVOUBIEL cy Bieler Se Blige: ec oes ea ua tI 3.97 TE SLAIN sie oa oe ON > ERNE ERR = Cn a 4.55 Specimen number 27 is a coarse grained gray lava from the west slope of the Silver Peak range, south of the Cave Spring road. It shows large plagio- clases up to one-half inch or more in diameter. Microscopically, the rock has a microgranular groundmass which gives a Becke reaction for alkaline feld- spar. In this groundmass are imbedded phenocrysts of andesine, labradorite, biotite, and augite. Magnetite and apatite are present as accessories. BASALT Dark feldspathic lavas containing basic plagioclase or labradorite and the ferro-magnesian silicates, pyroxene, and olivine are called basalt. 24 Sonora folio and Bulletin no. 89, U. S. Geological Survey. 258 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE Such rocks are abundant in the quadrangle. The largest flow is that of Piper Peak ridge. This basalt differs from the other flows in being rather coarse in grain and in containing more hypersthene than olivine. Chemically this rock is richer in silica than most basalts, as may be seen in the following analysis: Partial Analysis of the Basalt of Piper Peak, Number 590 George Steiger, Analyst Sili€a. 2.0. 4.4246 225s eee eeeee aS eee eee 04.78 Macnesia: : ...sekeccemee oie koe tins hee eee 3.55 EAMG 305 tS BOR BS CESS ORE es A Oe ee eee 7.48 SOUS. es SS Eee See Les ee ee ee 3.28 Potash 23 25 6 ees44 45 3% sia ae ee eee eee 2.44 Most of the basalts of the quadrangle are of the ordinary olivinitic type. They are dark heavy rocks, often scoriaceous, usually showing minute yellow grains (olivine) to the unaided eye. The Pleistocene basalt of the Clayton Valley crater is largely in the form of lapilli; that is, more or less rounded, scoriaceous fragments. THE SUCCESSION OF THE LAVAS IN GENERAL The oldest lavas observed in the region are the meta-rhyolites and associated lavas of the Cambrian and Ordovician periods. Between Paleozoic and Tertiary time there appears to have been a cessation of volcanic activity. In the Tertiary era the quadrangle was the scene of frequent and pro- longed eruptions, and the lavas and tuffs of this era are so related to the deposits of the Esmeralda formation that the age of some of the eruptions has been in part definitely ascertained. OLDER BASALT What are perhaps the oldest lavas are certain basalts which form narrow bands near the supposed base of the Esmeralda formation in Ice House canyon and vicinity, associated with red conglomerate beds. OLDER ANDESITE South of the Cave Spring road, at the west base of the Silver Peak range, are dikes and intruded sheets of altered andesites in the there hardened sandstones. These may be as old as the basalts above re- ferred to. OLDER DACITE In the Miocene sandstones and slates near the coal mines are inter- bedded layers of a dacite-tuff. This is composed of crystals, broken or SUCCESSION OF THE LAVAS 259 entire, of plagioclase, sanidine, quartz, and biotite, in a groundmass that appears to be devitrified glass. A similar dacite, but massive instead of fragmental, is found farther west, at the north base of the range, and this is probably of the same age as the tuff in the Miocene beds. ANDESITE AND RHYOLITE Higher up in the lake beds, apparently near the middle of the forma- tion, are rhyolite and andesite tuffs, the andesite being of the normal type. In the ravines at the east base of the Silver Peak range, just south of the Emigrant road, there is a layer of andesitic breccia about 20 feet thick, interstratified with lacustral marls, and 200 feet higher up, or to the east, is a thicker layer of rhyolitic tuff. Both of these layers contain silicified wood. What are perhaps the same layers are to be seen in the lake beds to the east of the Silver Peak road, in the south end of Big Smoky valley. There are also pebbles of andesite and rhyolite in the older conglomerates of the Esmeralda formation, about 3 miles west of Rhyolite ridge. A very striking evidence of the succession of lavas is seen in the ridge west of Ice House canyon when viewed from Fish Lake valley. At the west base are gray andesite breccias 800 feet in thickness ; next, white rhyolite tuffs of about the same thickness capped with a flow of dark basalt; but if we go up Ice House canyon we will observe that the succession is not so simple, for overlying the rhyolite tuffs above referred to is another extensive andesite-tuff area, succeeded by other rhyolite tuffs and pumice, which to the east of the canyon are associated with and appear to be interbedded with sandstones of the Esmeralda formation. The highest, and therefore most recent, tuffs and pumice beds are finally capped by the coarse basalt of the Piper Peak flow, which is an hypersthene-basalt, while that of the ridge west of the Ice House canyon is a normal, dark, fine grained, olivine basalt. The succession of lavas in Ice House canyon would then apparently be: 1. Older basalt associated with the red basal conglomerate of the Esmeralda formation. . Andesite-breccia. . Rhyolite-tuff. . Andesite-breccia. . Rhyolite-tuff and pumice. . Hypersthene-basalt of Piper peak. . Dark fine grained olivine-basalt, which may or may not be later than the Piper Peak flow. “1S Ol BP & bo In the northern foothills of the Palmetto mountains and the adjacent foothills of the Silver Peak range there are extensive areas of hornblende and pyroxene-andesite overlying rhyolitic tuffs and pumice, and this is 260 H.W. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE true of nearly all occurrences in these foothills. An exception is to be noted in the basin 6.5 miles southeast of Cow camp, where there is a later white pumice (presumably rhyolitic) overlying andesite-breccia and con- glomerate. This pumice should probably be correlated with the pumice beds of the Monocline, which are possibly of early Pleistocene age. LATITE The alkali-rich andesite or latite of the ridges north of Piper peak distinctly overlies the rhyolite-tuffs of that region. LATER DACITE The occurrence of a dacite near the base of the Esmeralda formation, at the north end of the Silver Peak range, has already been noted. This is undoubtedly older than the bulk of the true rhyolites. At many points there are layers of a later dacite intercalated in the rhyolitic tuffs. This is the dark glassy variety represented by analysis number 53. These layers can be seen along the south base of Rhyolite ridge and to the southwest of Piper peak as well as at many other points. We thus have eruptions of dacite of two periods—one near the beginning and one near the middle of the Tertiary volcanic period. HYPERSTHENE-BASALT The coarse basalt of the Piper Peak ridge overlies rhyolitic pumice at many points. It also overlies the massive alkali-rich andesite or latite of the north end of the high ridge that extends north from Piper peak. OLIVINE-BASALT An older basalt has already been referred to. Near the west end of Piper peak ridge there are olivine-basalts which form layers in rhyolitie tuffs and gravel beds; but these layers are pretty certainly intruded sheets and of the same age as the similar basalts which cap the same gravels of the Esmeralda formation in the vicinity. Basalt overlies andesite about 2 miles northeast of Barrel spring. Olivine-basalt overlies rhyolitic tuffs and pumice at the Monocline and other neighboring points; also on the high butte 5 miles southwest of Silver Peak; also on the table mountain 5 miles southwest of Piper peak, and, as already noted, on the high ridge west of Ice House canyon. In general it may be said that the basalts form the latest lavas of the quadrangle. PLEISTOCENE BASALT Finally there may be mentioned the basalt of the Clayton Valley crater, undoubtedly of Pleistocene age and representing the last volcanic erup- tion of the quadrangle. CONTACT METAMORPHISM 261 We may then summarize the succession of the lavas as follows: Older basalt ? Older andesite ? Older dacite ? Andesite ? Rhyolite. Andesite. Rhyolite. Alkali-rich andesite or latite. Piper Peak hypersthene-basalt. Dark olivine-basalt. Clayton Valley crater basalt. If we omit consideration of the older basalt, which apparently nowhere was erupted in any considerable mass, we have a repetition of eruptions of intermediate (andesite) and acid (rhyolitic and dacitic) magmas, culminating with basic lavas (basalt). Contact METAMORPHISM PYROXENITE The Paleozoic section north of Clayton valley has already been referred to. The large area in which this section was measured contains numer- ous dikes. ‘They are in part acid lavas and in part diorite. At one point on the northwest side of the area are small bodies of a green pyroxene rock, along the contact of an intrusive hornblende-mica-gabbro. This pyroxenite may have formed from the metamorphism of the adjoining dolomite, inasmuch as the dolomite itself contains monoclinic pyroxene in isolated grains and groups of grains. At another locality, at the con- tact of limestone with a granite mass, another lime silicate mineral, vesuvianite (see analysis below), formed, mixed with garnet and quartz. Some of the slates along the contact were metamorphosed likewise into schists. The pyroxene in the dolomite and the vesuvianite appear to be contact metamorphic products formed by recrystallization due to the heat and vapors of the intrusive granite rocks. Analysis of Vesuvianite, Specimen Number 186” George Steiger, Analyst SSTKO)S “Sl is eathee Stckatiter rer Sein Ant seins dears aa 36.80 MT CO) am ese ferre Sis wah ee LA Cae te ate alloy a 4 Sa 0.66 AJL) mere pica sain 6 eee IPA ete ie Oa i ot ett iS. TENA as Ss Geet ONE Se eee RES ties IR Om UE RR 1.56 RO) Beene ene he ented ss cot exicvereeetodanere ghee cereaye eae Ribs sushi ho AE. § a all DTrace ere ete NRW Eee aU poe DEE AL Laks Giese snese'y 0.48 JNU O) eet once, obbidie’ Giacetne cme aE SS RNEOL RE NCTE: Sore ET Or rea tn Ana Ibo; 262 H.W. TURNER—-GEOLOGY OF THE SILVER PEAK QUADRANGLE Na,O 6 i .iods Jao Dee ee 0.13 BLO 2 5s bi Seek eee Woe ee nee eee eee Doe eee 10 HO =F ne se oe eee Se oe ee eee eee ee eee 1.56 COs .5 65a ee She aa ee ee ee ee eee 65 | i 0 ee ee eee er eM a 8 - 07 SOs. ocd 3c oh 4 aie Reece aie ee eee en ee eee none OD cise Serta 30.5 Soi Wea Ee a SER EE ee eee Se et oe eee none Woolies cond cdee wee Pe oie eee ee eee ee .88 BaQ: ooas kb. 2 oeslooe se cbs eee ee COR eee none 99.92 Less 0. equal to 2. c.0 2.2 cask ceeekhn eee eee 36 99.56 Boron was looked for, but not detected by blowpipe test. SERPENTINE In the Palmetto mountains, at the south end of the quadrangle, there are a few small masses of serpentine. These areas lie at the contact of quartz-monzonite and other rocks, in part meta-rhyolite and in part limestone or dolomite and chert. There is more or less carbonate of lime in the serpentine and frequently bunches of pyroxenite, and the pyroxene of this rock appears to be the original mineral of the serpentine. An analysis of the pyroxene shows it to approximate to diopside in compo- sition. Analysis of Pyroxene from Specimen Number 323 George Steiger, Analyst SIO, <2.5409 oe wiiwte st tes. SoC aeee see ee eee eee 46.04 ALO, 5 (ods FESS aS eee eee eRe eee ae eee 12 WELO) «35s ok 6 Sms ciemyases ele os eae ER Eee eae 5.247" MeO) 2o3 cack occ tk cw obec cee bree oe eee 16.98 CaOe Bea i wc wk ccs alas cae eit ee ee oe 25 2 It has been shown that diopside is sometimes formed by the metamor- phism of magnesian limestone,?* the diopside afterwards altering into serpentine. It is regarded as probable that like transformations account for the serpentine of the Palmetto mountains. CHLOROPAL In a streak of a light colored felsitic rock inclosed in Ordovician ehert, 2 The vesuvianite was freed from the associated garnet and quartz by means of the Thoulet solution.—H. W. T. 78 Includes any TiO, and P,O, that may be present. 27 Includes any Fe O calculated as Fe,0.. 2G. P. Merrill: On the serpentine of Montville, New Jersey. Proceedings of the U. S. National Museum, vol, 11, pp. 105-111. Bi: STRUCTURAL FEATURES 3 263 there was found a sort of vein deposit of a yellowish material. The locality 1s about 15 miles southwest of Silver Peak. A sample of the rock was treated chemically with the following results: Analysis of yellow Mineral, Specimen Number 391 ‘George Steiger, Analyst Insoluble, less Si0,; soluble in Na, CO, after treatment with HCL........... 51.5 SiO treatimenbswablwbel Olives Gils. we see cia ce ccd par cbereelace sc 19.0 Hie ©) SOM, Coumnytlel @ leere ears spec eee neta esc eran aN elas keto es 13.5 ORSON! Grunt kell enh cen NY nem eters cicie chavs sislv tierce ere Gok meiatt/eeevattels 3.4 GAG): CMO 6) ey staal is UO) kee 1 aaa Aen eae et a ee aL Ra Bn US rds Ba 3) RENTS Ss tig ee Boo Shee ea Sone eC er ee ie ee Pn ee none ep Oxcalicmlated: bys ditterencer sax fn seek ois « daidisials as Rare feed oles 9.5 CO rca culatedvirow arc as lc Fe See eit Oe a Cale oui ie bee Se 2.6 100.0 Leaving out CaO, CO,, and insoluble less silica soluble in Na,CO;, and calculating to 100 per cent: SH ne » ab Gaetts Leelee Men tet tte UA sant SNE age en eA a rene er ERC 44.8 LE'S5( Olle e.g) dite ee pec he Set rae LE RC a a RES 31.8 LITE oo al gh CCR ey On eeu SBN ROD EPEC gO ama 1E2, TEL 5 5 a elect ae tie a ee UN SIME: gnc a Sere a 22.9 100.0 The yellow mineral removed from the impurities thus corresponds closely with chloropal. STRUCTURAL FEATURES It appears probable that the valleys of the region are in part or perhaps largely of orographic origin; that is to say, they represent subsided areas. Elevation of ranges and subsidence of valleys may be presumed to go on simultaneously. Such movements are usually accompanied by normal faulting, and there is good evidence outside of the topography that normal faulting has taken place in the quadrangle. One of the demonstrated fault-planes lies at the north base of the Silver Peak range, and the steep north slope is ascribed to uplift along this fault. It is perhaps hardly correct to call this steep slope and other similar slopes a faultscarp, for the original scarp has long since been: removed by erosion. Figure 2, plate 9, is a view of this scarp from the north. The rocks of the scarp are in large part rhyolitic tuffs and massive rhyolite. Ordovician sediments form a portion of the western part of it. To the north of the scarp are the lake beds (Esmeralda formation). These consist here largely of sandstone containing coal seams. At the contact with the scarp these beds are highly contorted XXIII—BULL. Grou. Soc. AM., Vou. 20, 1908 264 H. Ww. TURNER—GEOLOGY OF THE SILVER PEAK QUADRANGLE and broken and at some points stand vertical. A basalt dike has been intruded along the fault, and this is shown as a dark ridge in the mid- dle of figure 2, plate 9. I am informed that a thirty-foot gouge was passed through in prospecting a coal seam close to the fault. This doubt- less represents the exact line of faulting. To the north of the fault zone the sandstones dip evenly to the north at angles of from 25 to 35 degrees. This line of faulting was first recognized by M. A. Knapp, a mining engineer, when examining the coal beds. The steep north slope of the Palmetto mountains is also regarded as due to uplift along a normal east-west fault, the existence of which is further indicated by a rhyolite dike intruded along a part of it and by a line of vigorous springs, two of which are shown on the topographic map, one being at Indian Garden. Some of these springs are warm. ~ What is presumably a continuation of this line of faulting is a fault wall (shown in figure 1, plate 9) in the northern foothills of the south- east end of the Silver Peak range. This wall shows slickensides. It is composed of a friction breccia of rhyolite hardened by infiltrating waters, and was traced by exposures similar to that shown in figure 1, plate 9, for a considerable distance. Other croppings of this fault breccia may be noted in the distance in the figure. | The slates and limestones of the Lower Cambrian of the west side of the Silver Peak range south of Emigrant pass have been uplifted along a north-south normal fault for a distance of several miles, and the coarse conglomerate beds of the Esmeralda formation here dip to the west or away from the fault line, and at the fault line itself there is distinet evidence of faulting. What is probably a strong north-south fault zone forms the steep escarpment facing west of the rhyolite hills 10 miles southeast of Silver Peak. The north continuation of this fault line is east of the Silver Peak quadrangle. It is expressed in a steep scarp of Paleozoic rocks (probably Cambrian) that lies 8 miles due east of Silver Peak, exposing a very fine — section that has not yet been examined by a geologist, so far as known. Still farther north the northeast end of the Clayton marsh abuts against this fault wall, the continuance of which still farther northward is indi- cated by a narrow north-south valley. Smaller faults of the normal type are abundant, erosion along them often forming vertical walls which show smoothing and grooving due to movements along the faults. One of these walls has been used as a wall to a storehouse near the spring that furnishes drinking water to the town of Silver Peak. . BULL. GEOL. SOC. AM. WOOL. ZO), 9G; (PL. HIGURE 1.—PAULT WALL, HARDENED BY INFILTRATED WATER, AND SUBSEQUENTLY EXPOSNHD BY HWROSION FIGURE 2.—BEDDED VOLCANIC ROCKS AT THE NORTH END OF THE SILVER PEAK RANGE FAULT WALL AND BEDDED VOLCANIC ROCKS, SILVER PEAK RANGE us " . Come 5 ’ ‘ 1 . i ' 2 . C s. ¥ . A 4 eat wy > \ 1 « : i i / | X ’ f ¥ \ ah = 2 oP ole 2 ¥, G 7) . 4 r iy : , r 4 a 3 “ 5 5 Ppt yi . b) j . . a . ‘ ~ 7 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 265-332, PLS. 10-15 JULY 28, 1909 KINDERHOOK FAUNAL STUDIES—V, THE FAUNA OF THE FERN GLEN FORMATION? BY STUART WELLER (Presented before the Society December 31, 1908) CONTENTS Page aaMMMMNENARC HATO MAP =Repsts hee sy 7. ale 29S c. cis ec wa a, ld olokal nie piel avin 'eomlet Si osha SiuUbe iw Ade es ele 265 ME eiethat MIMO PES CCLES = 2 hia isin oie oie icle tas brela dares cea sie Sala sales eal eee oeee cee se 2HY ten MUNITIES), tate ole a ches ofS ine Yoisue nerorcue¥eueke’s bie wo kh 6 biwld s iets Net Nee ak ns gO 269 Peta e MRAM He Oe (ob). yo) e Habe ed Sencha eh ake Goeciceusi ce lebeieae e's ORs ase tbrain Blob oek he led abel e 269 TET EMU SEL yc GRA OR GeO OEE R RA MIN Pal ere Sa be nae 278 TENE SODIE GAL cp 6a: Sa yR cache aR (Oe a Pa aba eo ee 288 MMA PE TUM GS eG ions Wed SRA Vier ces RO see rele ai Sah Mia ad Oe Oe Peete BOO te OTUpINaTEOL Cl Meares eve hal By cit hehe raeavcts cal evetaeay Scola s,m Sal etats aPath dha said avd valet ae OD Pee RMN AMM Sorrel oy Se or Cid. candid he elated ee A eee Geen Soke ala IOy Bde PM oe 318 OTASOT UTEGIE: © ocd at aah ie a. SMe raed ie gNe ce pe ce gs AO ae eee Ee ena 319 See EMR AN tpt oh nt > eye cea al i A Ea he a aye Saale aie Balad Ghee oe 320 ase Se TPE EI th SA es a Ps gt cans Mee ee aunty, she aseele Sis Oe lS 8. Bile ah WE Sie se eile oe hora 320 TR ENESEINTIL 5.0 0 GhGgphe CucneOnStckcy 5 glean Saati fs ee iam ie a ge 321 Niame e Man Ara te ene GAC oe ee ee ne ee Oe ade Ste Saas 321 Relation of the Fern Glen to the Chouteau and Burlington........... oz Sit TUM O TINY LES «osc src.cis Goold esac dS bose Guleic oo ve ele elele pele oc auele ¢ aeo eR CVV mE TOVIGENCE SAIC. oo 5 sccle cic aw ale leve wveloved ele wee bid pieceseeytiole sieie aes 325 Cm ae mVEMIOV DCO Si. ie 6 lateral sides. Posterior to the central plate of the dome, and lying be- tween it and the large posterior interradial plate, is the large anal opening which is directed upward. The dimensions of the type specimen are: Height, exclusive of the basal plates, 13 millimeters; width of dorsal cup, 14 millimeters; width of calyx to the ends of the radial nodes of the ventral disk, 17.5 millimeters. Remarks.—This species may be recognized by its strongly stellate ap- pearance when viewed from above. Because of the position of the arm openings beneath and even in the lower side of the prominent radial nodes, the arms must have been more or less pendent when they were present. PLATYCRINUS SPRINGERI n. sp. Plate 11, figures 17-19 Description.—Calyx small, subglobular in form, wider than high. Base very shallow, saucer-shaped, the diameter of the basal disk a little more than one-half the diameter of the calyx between the arm bases. Radials wider than high, their surface gently convex, the facet for the attachment of the costal plates about one-half the total width of the plate. The first XXV—BULL. GnoL. Soc. AM., Vou. 20, 1908 aa 282 S. WELLER—FAUNA OF THE FERN GLEN FORMATION costal plate is axillary and extends horizontally from the calyx, with a distinct constriction at its proximal extremity, dorsally and laterally. The surface of the dorsal cup is marked with rounded tubercles; on the base they are arranged in a circle of ten around the stem facet, with usually an additional one or two in each distal angle of the disk; each radial plate carries five or six similar tubercles. Height of the ventral disk nearly equal to the dorsal cup. ‘The first interradial plates between the arm bases are nearly vertical in position, eight-sided, and with two other plates, supported laterally and ventrally, occupy the entire space between the bases of the rays; in all except the posterior side, these plates are flat, but posteriorly the central plate bears a low, rounded, central node. Above the base of the rays the ventral plates are nearly uniform — in size, slightly convex or obscurely nodose, and generally hexagonal in form, with a few usually inconspicuous smaller and less regular plates which are mostly situated just above the arm bases. The anal opening is eccentric and is directed ventrally. The dimensions of the type specimen are: Height of calyx,,7 milli- meters ; width at top of radial plates, 9 millimeters. Remarks.—In its tuberculate basal and radial plates this little crinoid resembles several species of Platycrinus from the Lower Burlington lime- stone, but it is clearly distinct from any of them. From the Kinderhook faunas no species with such distinctly tuberculate plates have been pre- viously described. The specific name has been given in honor of Mr Frank Springer, whose great familiarity with American crinoids has been most generously placed at the disposal of the writer in the identification of many of the obscure crinoidal fragments which occur so abundantly in the Fern Glen collections. RHODOCRINUS PUNOTATUS n. sp. Plate 11, figures 15-16 Description.—Calyx small, subglobular, contracted to the arm bases, with a deeply indented base. The plates marked by minute, closely arranged pits or puncte, which can only be seen with a magnifying glass. Underbasals minute, included within the excavated base and covered by the column. Basal plates the largest plates of the calyx, their proximal portions abruptly incurved to form the sides of the basal excavation. Radial plates heptagonal; first costals very small, quadrangular; second costals axillary, pentagonal or hexagonal in form, as large or slightly larger than the first costals; distichals one in each series, their distal mar- gins notched by the arm openings. First interbrachials a little smaller DESCRIPTION OF SPECIES—CRINOIDEA 983 than the radials, followed by two somewhat smaller plates, and these by two other much smaller ones which extend up to the level of the arm openings. Arm openings two in each ray; arms not known. Ventral disk depressed convex, small, its diameter much less than the diameter of the calyx at its mid-height. The dimensions of a nearly perfect calyx are: Height, 7.5 millimeters; diameter, 7.5 millimeters; diameter of ventral disk, 4.5 millimeters. Remarks.—This species most closely resembles Rk. worthent, from the Burlington limestone, but it has a more deeply excavated base, besides having the surface of the plates marked by the exceedingly fine pits or puncte. It also resembles R. watersianus W. & Sp., from the Kinder- hook at Le Grand, Iowa, but it may be distinguished by its more globular form and its proportionately much smaller ventral disk, the diameter of the circle formed by the arm openings in the Le Grand species being nearly or quite as great as that of the calyx at its mid-height, while in this species the circle has a much smaller diameter. The form of the first costal plates in these two species is also different, in the Fern Glen species this plate usually being quadrangular as it is in R. worthent, although occasionally an additional face may be developed on one side, while in R. watersianus this plate is commonly hexagonal. AGARICOCRINUS PRAICURSOR Rowley Plate 11, figures 7-12 1902. Agaricocrinus precursor Rowley, American Geologist, volume 29, page 303, plate 18, figures 1-5. Description.—Calyx subhemispherical or subglobose in form, dorsal cup flat or somewhat concave, ventral disk more or less dome-shaped. Basal plates small, often nearly covered by the column, the column facet either flush with the surface or slightly depressed. Radial plates smooth, flat or slightly convex, wider than long. First costals quadrangular, very short and broad; second costals much wider than long; in the two pos- terior lateral rays and sometimes in one of the anterior lateral rays this plate is axillary and supports two series of distichals which give origin to the arms; usually in all three anterior rays the first costal is followed by two other broad and short costals, the last one of which gives origin to anarm. Anal plate about equaling the radials in size, but proportionally longer and narrower, followed by three plates, each of which is nearly as large as the anal itself. The plates of the ventral disk exhibit consider- able variation in the different individuals, but the central plate at the summit is always the largest plate of the entire calyx and is broadly and’ 284. S, WELLER—FAUNA OF THE FERN GLEN FORMATION somewhat strongly convex; above the base of each ray are usually some- what strongly nodose plates, which are more constantly present above the two postéro-lateral rays and frequently consist of a series of large plates the upper one of which joins the large, central plate at the summit. The posterior interambulacral area is much larger than the others and is more or less strongly protuberant, the constituent plates being small and irregular; the anal opening is situated near the summit of this inter- ambulacral area and is directed upward. The dimensions of two individuals are: Total height of calyx, 16.5 millimeters and 14 millimeters; greatest width, 19.5 millimeters and 18 inillimeters. Remarks.—This species exhibits much variation in the convexity of the dorsal cup and in the prominence of the plates of the ventral disk, but may be distinguished from all other members of the genus by its small number of arm bases, there being usually seven, and among the indi- viduals examined never more than eight. The protuberant posterior interambulacral region is also a constant characteristic. The species was originally described from the typical Fern Glen beds at Fern Glen, Missouri. LOBOCGRINUS PISTILLIFORMIS (M. &€ W.) Plate fet figure 6 1861. Actinocrinus pyriformis var. rudis M. & W., Proceedings of the Academy of Natural Science of Philadelphia, page 131 (not A. rudis Hall, 1860). 1865. Actinocrinus pistilliformis M. & W., Proceedings of the Academy of Nat- ural Science of Philadelphia, page 153. 1866. Actinocrinus pistilliformis M. & W., Geological Survey of Illinois, volume 2, page 151, plate 14, figure 8. Description.—Calyx, exclusive of the anal tube, pyriform, being very narrow and apparently cylindrical from the base to the distal extremities of the costal plates, above which the distichals and palmers curve abruptly outward to the base of the arms, forming with the ventricose ventral disk a much expanded visceral cavity entirely above the costal plates. Basal and radial plates not known. First costals very small, a little wider than long, irregularly pentagonal in form so far as seen, one of the sides being much shorter than the others. Second costals axillary, as long as the first and nearly one-third wider; the only two visible in the type specimen are hexagonal in form, and each supports on its distal sloping sides two dis- tichals of about its own size. Second distichals somewhat larger than the first, each of which supports two palmers, which in turn are succeeded by DESCRIPTION OF SPECIES—CRINOIDEA 285 a second palmer, from which the free arms are given off. The two series of distichals and the four series of palmers in each ray are in contact laterally. Interbrachials two or three in each inter-ray, the first being of about the same size as the first costals and hexagonal or heptagonal in form; above this there are one or two small plates of variable size and form, over which the distichals and lateral series of palmers of the rays on each side are in contact all the way to the free arms. Anal plates un- known. Ventral disk hemispherical, composed of pentagonal, hexagonal, and heptagonal plates of nearly uniform size, each of which is provided with a central, spine-like tubercle. Anal tube central or nearly so. Arm openings twenty. Surface of plates smooth or obscurely granular; small pointed tubercles are also present on the costals, distichals, and first inter- brachials. The dimensions of the type specimen are: Diameter at arm bases, 25 millimeters ; height from top of radial plates to the base of the anal tube, 26 millimeters; probable total height of calyx, exclusive of the anal tube, 37 millimeters ; height of ventral disk, 15 millimeters. Remarks. Enis species was originally described by Meek and re from the Fern Glen beds at Salt Lick point, near Valmeyer, Madison county, Illinois. It was later considered as a synonym of the Burlington Lobocrinus pyriformis (Shum.) by Wachsmuth and Springer,® but it seems to be sufficiently distinct from that form to be considered as a dif- ferent species. It is especially distinguished from L. pyriformis by reason of the greater development of spine-like tubercles upon the plates of both the dorsal cup and the ventral disk and in the smaller number of inter- brachial plates. The species has not been detected in the recent collec- tions of Fern Glen material and it is known only from the original type specimen described and figured by Meek and Worthen. ACTINOCRINUS RUBRA n. sp. Plate 11, figures 4-5 Description.—Calyx about as wide as high, the arm openings situated midway between the top of the column and the base of the anal tube, the profile view of the specimen being subquadrangular. Dorsal cup obcon- ical, the sides straight from the basals to the tops of the axillary costals, beyond which point the plates of the rays bend abruptly outward to a nearly horizontal position for a short distance. Basal plates rather small ; radial plates the largest in the calyx, nodose, with raised, rounded, radia- ting ridges passing from the central node to each of the adjoining plates, 5 North American Crinoidea Camerata, p. 437. 286 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION the longitudinal ridges the most prominent and continued distally upon the brachial plates as distinct radial ridges; first costal plates smaller than the radials, crossed longitudinally by the strong, keel-like radial ridge, and with much weaker raised ridges passing laterally to the first interbrachial plates; second costal plates axillary, the strong radial ridge bifurcating at the center of the plate and the two distal divisions passing to the distichal plates; normally there is a single axillary distichal plate in each series, each of which supports two palmer plates which are the last brachial plates included in the calyx; the distichal and palmer plates are directed in a nearly horizontal direction, the interdistichal region in each ray being deeply depressed, with an interdistichal plate between the arm bases. Anal plate somewhat smaller than the radials; above the anal are two slightly nodose plates with raised radiating ridges passing to the adjoining plates; these two plates are followed by three nearly smooth plates, and these by others between the arm bases. First interradial plate of each area nodose, with raised, rounded, radiating ridges passing to each of the adjacent plates; these plates support two plates distally which are smooth and flat or with only faint radiating ridges. Ventral disk conical to the base of the anal tube, with the sides nearly straight; moderately depressed to the interradial spaces between the arm bases, the small plates flat or gently convex, the larger ones with low, broad, rounded nodes; three plates arranged in a triangle above the arm bases of each ray are the most conspicuously nodose. Base of the anal tube central. Arm open- ings four in each ray. The dimensions of the type specimen are: Height to base of anal tube, 31.5 millimeters; height of dorsal cup, 16 millimeters; diameter at base of arms, 32 millimeters. Remarks.—This species is established upon a single, slightly distorted calyx, which is complete to the base of the anal tube. The specimen is slightly abnormal in the right anterior ray, in which there is but a single costal plate, but in this ray both the radial and the single costal are some- what larger than are the corresponding plates in the other rays. PHYSETOCRINUS SMALLEYI n. sp. Plate 11, figures 1-3 Description.—Calyx wider than high, the ventral disk much higher than the dorsal cup, the depressions between the rays narrow. Dorsal cup broadly obconical to the top of the costal plates, beyond which the brachial plates bend outward in a nearly horizontal direction ; costal plates strongly nodose, the nodes of successive plates connected more or less completely DESCRIPTION OF SPECIES—CRINOIDEA 287 by a rather sharp radial ridge which is continued on the higher brachial plates of the calyx. Basal plates very short and forming a flat, disk-like base, or of moderate height; the radials about equal to the basals in size, with three nodes arranged horizontally at their middle line or with a single transverse node; first costals about equal to or a little smaller than the radials, hexagonal in outline, with a tendency to a trinodose orna- mentation similar to that of the radials, the central node connected by a ridge with the central node of the radial; second costal pentagonal, axil- lary, strongly nodose, the node connected proximally with the central node of the first costal and distally with the distichal plates; distichals one in each series, broader than high; palmers with one or two plates in each series incorporated in the calyx; a deep V-shaped interdistichal groove marks the median line of each ray distally; arm openings four in each ray. Anal plate smaller than the radials, nodose, followed by two plates in the second series and three in the third, all of which are usually nodose. Interbrachial series consisting of three more or less strongly nodose plates, one below and two above, and these usually followed by two elongate plates between the bases of the rays. Ventral disk dome-shaped, much higher, sometimes twice as high as the dorsal cup, slightly depressed between the rays below, composed of numerous more or less nodose polygonal plates, those occupying the ambulacral regions being the most strongly nodose, some of the nodes almost assuming the form of short spines ; anal opening almost central, with no anal tube. The dimensions of a large individual are: Height, 27.5 millimeters; height of dorsal cup to arm openings, 10 millimeters; greatest width, 34 millimeters. ‘The dimensions of a smaller individual are: Height, 21 millimeters ; height of dorsal cup to arm openings, 7% millimeters; width, 24.5 millimeters. Remarks.—This species is founded on the two nearly complete calyces whose dimensions are given above, both of which were collected bv Mr F. A. Sampson. The two specimens differ somewhat in minor charac- ters; the basals of the smaller individual are slightly higher and more nodose; the nodes on the radials and first costals are more distinctly tri- partite in the larger specimen; the interradial depressions are relatively broader in the smaller specimen, a feature which may be due to the age of the individual. | At the request of Mr F. A. Sampson this species has been named in honor of Mrs C. T. Smalley, who has skillfully prepared many specimens of crinoids in his collection, including the ones here described. 288 S. WELLER—FAUNA OF THE FERN GLEN FORMATION MESPILOCRINUS sp. Plate 11, figure 26 Several specimens of a tripartite crinoid base in the Fern Glen fauna have been recognized by Springer as the underbasals of a flexible crinoid, probably belonging to the genus Mespilocrinus. This identification is strengthened by the undoubted presence among the crinoid fragments of the peculiar column joints of this genus. METICHTHYOCRINUS sp. Plate 11, figure 25 A fragment of a dorsal cup, including the base and the radials, has been recognized by Springer as Metichthyocrinus. This genus has not hitherto been recognized in beds older than the Lower Burlington. BLASTOIDEA PENTREMITES DECUSSATUS Shumard 1857. Pentremites decussatus Shumard, Transactions of the Saint Louis Acad- emy of Science, volume 1, page 242, plate 9, figures 6a-b. Plate 11, figures 28-29 Description—Body subovate in form, broadest below the middle. Basal plates very small, apparently forming a flat, horizontal disk.) Radial plates very long, their proximal extremities inflected and probably being in nearly the same plane as the basal disk; the ambulacral sinuses very deep, their lower extremities extending nearly to the edge of the inflected, proximal portion; just below the very base of the sinuses the surface of each radial plate is produced into a low but distinct, pointed tubercle. Deltoid plates distinctly angular below, their height being about two-sevenths of the height of the lateral limbs of the radial plates. Ambulacral sinuses moderately wide, the width increasing toward the summit; the lancet plate entirely covered in the lower portion of the ambulacral area by the side plates, but toward the summit it is possibly exposed to a slight degree; the side plates are rather large, a little oblique in position, their inner extremities directed distally to a slight degree; those of the two series alternate in position ; the median line of the ambu- lacra marked by a zigzag median furrow; the inner extremities of the side plates have a very narrow, slightly raised border, behind which is a depressed band marked by very fine transverse crenulations. The lateral surfaces of the radial and deltoid plates, from the base of the radial sinuses to their summit, are beautifully marked by fine, transverse coste f DESCRIPTION OF SPECIES—-BLASTOIDEA 289 and by less strongly developed longitudinal lines, the longitudinal lines being strongest toward the base. The characters of the spiracles and the summit are unknown. The dimensions of a nearly complete but badly crushed example are: Height, 20 millimeters; greatest width approximately, 15 millimeters. Remarks.—This species was first described from detached radial plates found at “Button Mould Knob,” south of Louisville, Kentucky. The Fern Glen.examples agree exactly with the Kentucky specimens as thev have been described and illustrated, the essential feature of the species, aside from its general form and proportions, being the peculiar orna- mentation of the plates and the form of the side plates of the ambulacra, with their finely crenulated inner extremities. The Fern Glen specimens are all more or less fragmentary, the best example seen being one col- lected by Mr Sampson. This specimen is nearly complete, but is so erushed laterally as to destroy the characters of the base and the summit. - MOLLUSCOIDEA BRYOZOA In addition to the species here noted, the Fern Glen fauna contains several other forms of Bryozoa which are represented by material which is too imperfectly preserved for certain identification or for description. Several of them, however, are probably undescribed species. FISTULIPORA FERNGLENENSIS n. sp. Plate 15, figures 1-2 Description.—Zoarium consisting of more or less subcircular or ellip- tical disk-like bodies, or of irregular expansions, apparently free or attached only by the center of the disk, the under surface usually concave and covered by a wrinkled epitheca. Celluliferous surface convex in the subcircular examples, with a more or less irregular contour; monticules and maculee ill defined or obsolete. Zocecial apertures with a more or less regular quincunxial arrangement, more or less oblique, subelliptical in outline, with a broad and shallow but distinct lunarium on one of the longer sides of the ellipse; their longer diameter is .4 millimeter to .5 millimeter, the shorter being about three-fourths of the longer; the dis- tances between the apertures is about one and one-half times the width of the apertures themselves. In tangential section the interzoccial vesicles are seen to be polygonal in form and are usually two in number between adjacent zoccia. In longitudinal section the zocecia seem to lack diaphragms altogether, although they may rarely be present. 290 S. WELLER—FAUNA OF THE FERN GLEN FORMATION The dimensions of two disk-like zoaria are: Diameter, 26 millimeters and 45 millimeters; maximum thickness, 6 millimeters and 10 milli- meters. CHILOTRYPA AMERICANA S. A. M. Plate 15, figure 3 1881. Trematopora americana §. A. M., Journal of the Cincinnati Society of Natural History, volume 4, page 312, plate 7, figures 5-5a. Description.—Zoarium consisting of more or less irregular, subcylin- drical branches, 2 to 10 millimeters in diameter, the smaller ones some- times solid, the larger ones with an axial cavity. Zocecial apertures arranged irregularly, ovate in outline, their margins slightly elevated in a thickened lip; lunarium usually rather obscure, the intervals between the apertures three or four times the width of the apertures themselves. Surface of the zoarium elevated at intervals in rather large, undefined monticules, upon which the zocecia are more widely scattered. Remarks.—Miller’s species, T'rematopora americana, was described without mention of the internal characters, and the present Fern Glen examples are identified with it on the strength of the external features alone. In these characters the Fern Glen specimens agree very closely with Muiller’s figures and description. The species is clearly not a mem- ber of the genus Trematopora. It is one of the Fistuliporide and seems to correspond in all essential features with the genus Chilotrypa. CYSTODICTYA LINEATA Ulrich Plate 15, figure 4 1884. Cystodictya lineata Ulrich, Journal of the Cincinnati Society of Natural History, volume 7, page 37, place 2, figures 4-4c. Description.—Zoarium bifoliate, consisting of strongly compressed, sharp-edged, bifurcating branches. Surface of each face of the branches a little convex, with low, rounded, longitudinal ridges, between which the zocecial apertures are arranged in from seven to nine longitudinal lines; transversely the zocecial apertures are arranged in more or less regular oblique rows; the longitudinal ridges are most conspicuous and most continuous in the central portion of the branches; laterally they become more or less discontinuous and consist rather of a series of depressed nodes upon the inner slopes of which are located the zocecial apertures ; outside of the outermost zocecia is a narrow, smooth, or finely striated, non-poriferous margin; zocecia with distinct lateral lunaria, which give to the apertures a depressed pyriform outline; on either side of the DESCRIPTION OF SPECIES—BRYOZOA Pays median line of the branches the lunaria are situated on the outer lateral margins of the zocecial apertures, and the apertures themselves are directed with a slight obliquity toward the median line. The dimensions of an average example are: Width of branches of zoarium, 4 to 5 millimeters; greatest thickness of branches, .75 milli- meter to 1 millimeter; number of zocecial apertures in the space of 2: millimeters longitudinally, 3 to 4; number of zocecial apertures in the space of 2 millimeters transversely, about 4. Remarks.—This species is one of the less common bryozoa in the Fern Glen fauna. The species is usually identified from a somewhat higher horizon, being an abundant form in the Upper Keokuk, Salem, and Saint Louis faunas, but the Fern Glen examples agree more closely with the original description of the species than do those commonly so identified from the Salem and Saint Louis. EVACTINOPORA SEXRADIATA M. & W. Plate 15, figures 5-16 1868. Evactinopora sexradiata Meek and Worthen, Geological Survey of Illi- nois. volume 3, page 502, plate 17, figure 3. 1890. EHvactinopora sexradiata Ulrich, Geological Survey of Illinois, volume 8, page 510, plate 73, figures 2-2b. 1894. Evactinopora sexradiata Keyes, Missouri Geological Survey, volume 5), page 18. Description.—Zoarium free, with a stellate base, which is the only por- tion yet detected in the Fern Glen collections. Base with from four to nine rays, six being the most usual number; the rays are compressed laterally, their lower edge describing a convex curve from the center of the base to the tips of the rays; sinuses between the rays more or less variable in depth, the central disk varying from one-fourth to one-half the total diameter of the base. In the center of the lower side of the disk a small polygonal area is often present, outlined by faint ridges, the angles of the polygon being equal in number to and opposite the rays, and from each angle a similar ridge passes to the extremity of the ray along its median line; the size of the central polygon varies with the rela- tive size of the disk as compared with the total diameter of the base; in other individuals the ridges marking the rays join at the center of the disk in a regular or irregular manner without the polygonal inclosed area. The diameter of an average sized individual is 11.5 millimeters; the diameter of the largest example observed is 20 millimeters. 292 S. WELLER—FAUNA OF THE FERN GLEN FORMATION Remarks.—This species of Hvactinopora is one of the commonest and most characteristic members of the Fern Glen fauna and is highly varia- ble in form. Among 146 bases preserving all of the rays, 3 have four rays, 39 have five rays, 44 have six rays, 37 have seven rays, 18 have eight rays, and 5 have nine rays. Other characters in which the specimens vary are the relative size of the central disk and the thickness of the rays themselves. ‘The combined characters of all of these examples seem almost to include the characters of the three species, H. sexradiata M. & W., H#. quinqueradiata Ulr., and EF. radiata M. & W., but Ulrich’ figures of H. sexradiata best exhibit the most usual features of the spe- cies. H. quinqueradiata, as interpreted by Ulrich, has relatively longer and more slender rays, and H. radiata, as interpreted by the same author, has a much larger disk and is much higher in proportion to the diameter of the base. BRACHIOPODA CRANIA MISSOURIENSIS n. sp. Plate 12, figure 1 . Description—Shell rather large, subcircular in outline. The dorsal valve depressed convex, the apex rather obscure and situated excentrically about one-third the length of the shell from the anterior margin. Sur- face of the shell marked by rather fine but more or less irregular and uneven concentric markings. The dimensions of the type specimen are: Length, 17 millimeters; width, 17 millimeters. Remarks.—The type of this species has grown upon the interior of the pedicle valve of a Productus. The central portion of the shell is de- ‘pressed convex, but toward the margins it becomes concave, because of the strongly concave surface to which it is attached. Attached to some other flatter surface the shell would doubtless be depressed convex throughout. The species seems to be distinct from any of the described forms, although one or two Lower Mississippian species have been so briefly described without illustrations that they can not be recognized except through a study of the type specimens. LEPTA4NA RHOMBOIDALIS (Wilckens) Plate 12, figures 2-3 1821. Anomites rhomboidalis Wahlenberg, Acta. Society of Upsala, volume 3, page 65. 1836. Producta analoga Phillips, Geology of Yorkshire, volume 2, page 215, plate 7, figure 10. DESCRIPTION OF SPECIES BRACHIOPODA 993 1859. Strophomena rhomboidalis var. analoga Davidson, British Fossil Brach- iopoda, volume 2, page 119, plate 28, figures 1-2. 1877. Strophomena rhomboidalis White, U. S. Geographic Survey West of the 100th Meridian, volume 4, page 85, plate 5, figure 5. 1877. Strophomena rhomboidalis Hall & Whitf., U. S. Geological Explorations of the 40th Parallel, volume 4, page 253, plate 4, figure 4. 1888. Strophomena rhomboidalis Herrick, Bulletin of the Dennison University, volume 4, plate 9, figure 6. ; 1889. Strophomena rhomboidalis Herrick, American Geologist, volume 3, plate 4, figure 6. 1892. Leptena rhomboidalis Hall & Clarke, Introduction to the Study of the Brachiopoda, part 1, plate 13, figure 9. 1892. Leptena rhomboidalis Wall & Clarke, Paleontology of New York, volume 8, part 1, plate 8, figures 30-31; plate 20, figure 24. 1894. Plectambonites rhomboidalis Keyes, Missouri Geological Survey, volume 5, page 70, plate 39, figure 6. 1895. Strophomena rhomboidalis Herrick, Geological Survey of Ohio, volume 7, plate 20, figure 6. Description.—Shell transversely subsemicircular or subquadrate in outline, the hinge line straight, equaling the greatest width of the shell, the valves geniculate anteriorly and laterally. Pedicle valve slightly con- vex near the beak ; beyond the convex area it becomes flattened to the line of geniculation, where it is abruptly bent toward the opposite valve at nearly a right angle; on the flattened portion of the valve there are pres- ent a variable number of concentric undulations or wrinkles which are sometimes discontinuous and which bend outward toward the cardinal extremities as they approach the cardinal margin; beak small, not in- eurved, with a minute perforation which is sometimes obsolete or ob- secure; cardinal area rather narrow, with a wide delthyrium which is nearly closed by the cardinal process of the opposite valve when the two valves are in articulation, the deltidium being very small and re- stricted to the apex of the delthyrium. Brachial valve concave, the pos- terior portion flattened, bent abruptly upward toward the margin to conform with the pedicle valve; flattened portion of the valve marked by concentric wrinkles or undulations similar to those of the pedicle valve, the cardinal area narrower than that of the pedicle valve. Both valves marked, in addition to the concentric wrinkles, with very fine radiating strie. The dimensions of a specimen of average size are: Length, 20 milli- meters ; width, 28 millimeters. Remarks.—This is a rather common member of the Fern Glen fauna and does not differ essentially from members of this long range species from other horizons and localities. 294 S. WELLER—FAUNA OF THE FERN GLEN FORMATION ORTHOTHETES RUBRA n. sp. Plate 12, figures 4-5 Description.—Shell of medium size when full grown, wider than long, the hinge line straight and slightly shorter than the greatest width of the shell; lateral margins slightly convex posteriorly, becoming more strongly curved in front and rounding regularly into the anterior margin, which is nearly straight in the middle half of the shell; shell substance rather thick. Pedicle valve depressed convex, most prominent toward the beak, the surface sloping gently toward the front and a little more steeply toward the cardinal extremities with a slightly convex curve; cardinal area rather low, apparently flat, but not well shown in the type specimen. Brachial valve about as convex as the pedicle, slightly compressed toward the cardinal extremities. Surface of both valves marked by fine radiating coste, some of which are slightly larger than the others; the costz in- crease by intercalation and about three occupy the space of one milli- meter. The surface is also marked by fine concentric lines, which are apparently more conspicuous toward the cardinal extremities, on which parts of the shell the radiating costs appear to be minutely serrate by reason of the crossing of the concentric lines. A few more or less incon- spicuous lines of growth occur upon the main body of the shell, but in old examples the growth lines become much crowded toward the margin and the shell thickened. The dimensions of a nearly complete example are: Length, 25 milli- meters; width, 36 millimeters; length of hinge line, 32 millimeters; thickness, estimated, 10 millimeters. Remarks.—This species is rather rare in the fauna. It resembles O. lens (White), from the Louisiana limestone, but it grows to a much larger size, is proportionally broader, and is marked by somewhat finer radiating coste than that species. Some of the smaller and immature examples are of about the average size of the full grown specimens of O. lens, but they may be distinguished from that species by their form and coste. ORTHOTHETES 2? sp. A single imperfect internal cast of the brachial valve of a large Ortho- thetes or Derbya-like shell has been observed in the Fern Glen fauna which is too incomplete for identification. When complete the shell must have had a length of 40 millimeters and a width of about 55 milli- meters. It has a broad and strong cardinal process and was marked by rather strong concentric wrinkles. F DESCRIPTION OF SPECIES—-BRACHIOPODA 295 RHIPIDOMELLA MICHELINIA L’Eveille Plate 12, figures 8-10 1835. Orthis michelinia L’Eveille, Memoires de la Société Geologique de France, volume 2, page 39, plate 2, figures 14-17. 1858. Orthis michelini var. burlingtonensis Hall, Geology of Iowa, volume i, part 2, page 596, plate 12, figures 4a-b. 1858. Orthis michelinia Davidson, British Fossil Brachiopoda, volume 2, page 132, plate 30, figures 6-12. 1892. Orthis (Rhipidomella) burlingtonensis Hall & Clarke, Paleontology of New York, volume 8, part 1, plate 6A, figure 13; plate 20, figures 5-6. 1894. Orthis burlingtonensis Keyes, Missouri Geological Survey, volume 5, page 63, plate 38, figure 7. 1899. Rhipidomella burlingtonensis Weller, Transactions of the Saint Louis Academy of Science, volume 9, page 15, plate 4, figure 13. 1901. Rhipidomella burlingtonensis Weller, Transactions of the Saint Louis Academy of Science, volume 11, pages 150 and 181, plate 12, figure 3, and plate 16, figure 6. Description.—Shell lenticular in form, subcircular or subovate in out- line, as wide as or a little wider than long, the greatest width at or in front of the middle, hinge line short, one-third or less than one-third the width of the shell. Pedicle valve depressed convex, most prominent on the umbo, the surface sloping rather abruptly to the cardinal margin with a slightly concave curvature, and gently to the lateral and anterior margins with a moderately convex curvature; the median portion of the valve either not differentiated from the lateral surfaces or flattened or slightly depressed in a broad, shallow, ill defined sinus in the anterior half; in the posterior half of the valve the median portion is somewhat marked by a slight, ill defined median elevation; cardinal area small, a little concave, the delthyrium rather broad. Brachial valve with a con- vexity about equaling that of the pedicle valve; convexity nearly uniform, but sloping a little more abruptly to the cardinal margins, the median portion of the valve depressed in a rather broad, shallow, ill defined sinus which extends nearly or quite to the beak. Surface of both valves marked by fine, rounded, radiating coste, which increase by bifurcation and intercalation, about two or three coste occupying the space of one millimeter ; the surface also marked by concentric lines of growth which vary in strength and distribution in different individuals. The dimensions of one of the most complete individuals observed in the Fern Glen fauna are: Length, 20 millimeters; width, 20.5 milli- meters ; thickness, 9 millimeters. Remarks.—This is one of the most abundant species in the Fern Glen fauna, but it is of smaller size than usual for the species. A length of 296 S. WELLER—FAUNA OF THE FERN GLEN FORMATION 12 millimeters is perhaps an average size for the Fern Glen examples, although some of the larger ones grow to be 25 millimeters or more in © length. No specific differences can be detected, however, between the larger and smaller individuals associated in this fauna, nor between these and members of the same species elsewhere. The American examples of this shell have usually been considered as either varietally or specifically distinct from the European R. michelinia, but a careful examination of many specimens from various localities in both America and Europe has failed to bring out constant characters of any sort which can be used to distinguish the European from the American examples. The shell which Miller has called Orthis dalyana, from Lake valley, New Mexico, is perhaps identical with this Rhipidomella michelinia of the Mississippi valley ; it is certainly a member of the same genus, and if not identical is at least a closely allied species. SCHIZOPHORIA SWALLOVI Hall Plate 12, figures 6-7 1848. Orthis resupinata Christy, Letters.on Geology, plate 3, figures 1-2. 3 1858. Orthis swallovi Hall, Geology of Iowa, volume 1, part 2, page 597, plate 12, figures 5a-b. ; 1892. Orthis (Schizophoria) swallovi Hall & Clarke, Paleontology of New York, volume 8, part 1, plate 6, figures 23-24. 1894. Orthis swallovi Keyes, Missouri Geological Survey, volume 5, page 63, plate 38, figure 5. 1899. Schizophoria swallovi Weller, Transactions of the Saint Louis Academy of Science, volume 9, page 13, plate 4, figure 7. 1900. Schizophoria swallovi Weller, Transactions of the Saint Louis Academy of Science, volume 10, page 66, plate 1, figures 11-13. Description.—Shell biconvex, resupinate, transversely subelliptical in outline, the hinge line shorter than the greatest width of the shell, the cardinal extremities rounded. Pedicle valve depressed convex, most prominent on the umbo, the surface sloping rather abruptly to the car- dinal margin and more gently toward the lateral and antero-lateral mar- gins, the mesial portion flattened toward the front and sometimes, in the larger individuals, depressed into a more or less conspicuous mesial sinus which is ill defined laterally; beak rather small, moderately incurved ; cardinal margin of moderate height, sloping slightly backward from the plane of the valve and gently arched to the point of the beak, the del- thyrium about as wide as high. Brachial valve much more strongly con- vex than the pedicle, most prominent near the middle, the surface slop- ing rather abruptly to all sides, sometimes with an ill defined mesial fold toward the front, the umbo prominent, produced backward beyond the bie DESCRIPTION OF SPECIES—-BRACHIOPODA 297 hinge line, the beak more strongly incurved than that of the opposite valve, the cardinal area about one-half the width of that of the pedicle valve, arched and directed posteriorly and toward the beak of the. pedicle valve. Surface of both valves marked by small, rounded, radiating coste, about three of which occupy the space of one millimeter; the coste are separated by rounded furrows about equal in width to the coste them- selves; upon the pedicle valve the coste increase by bifurcation, and on the brachial valve by implantation; the surface is also marked by more or less crowded, subimbricating lines of growth. The dimensions of a rather large individual are: Length, 30 milli- meters; width, 36.5 millimeters; thickness, 23 millimeters; length of hinge line, 20 millimeters; height of cardinal area, 4 millimeters. Remarks.—This species in the Fern Glen fauna does not attain so large a size as it does in the Burlington limestone, where examples not infrequently exceed 50 millimeters in width, but in all other respects the Fern Glen examples are essentially identical with specimens from the higher formation. The species should probably not be considered as distinct from the European S. resupinata of the mountain limestone, but until a careful comparative study of the American and European forms can be made it is perhaps not advisable to drop the present name. The species is a close ally of the Devonian 8S. striatula; it differs from that species especially in the larger size to which 1t grows and in the much less development of the mesial sinus of the pedicle valve. CHONETES ILLINOISENSIS Worthen Plate 12, figure 11. 1858. Chonetes logani Hall, Geological Survey of Iowa, volume 1, part 2, page 589, plate 12, figures 1-2 (not C. logani N. & P., 1855). 1860. Chonetes illinoisensis Worthen, Transactions of the Saint Louis Academy of Science, volume 1, page 571. 1868. Chonetes illinoisensis M. & W., Geological Survey of Illinois, volume 8, page 505, plate 15, figure 8. Description.—Shell concavo-convex, the length from .6 to .7 of the width, hinge line usually a little shorter than the total width of the shell, but sometimes equaling the width. Lateral margins of the shell nearly straight or slightly convex posteriorly, directed at nearly a right angle to the cardinal line, more strongly curved anteriorly and passing with a regular arcuate curvature into the anterior margin, which is often nearly straight for a short distance in its central part. Pedicle valve depressed convex, somewhat compressed toward the cardinal extremities, flattenel along the mesial region and often depressed in a shallow, ill defined XXVI—BULL. GEOL. Soc. AM., Vou. 20, 1908 298 S. WELLER—FAUNA OF THE FERN GLEN FORMATION mesial sinus. Brachial valve concave, following rather closely the curva- ture of the pedicle valve; in none of the Fern Glen examples have the cardinal spines been observed. Surface of both valves marked by fine, nearly regular, radiating coste, which increase by bifurcation on the pedicle valve and by intercalation on the brachial valve; the total number of coste vary from 175 to 225, according to the size of the individuals, but there are constantly about 6 coste in the space of 1 millimeter. The dimensions of two individuals, the larger of which is slightly flat- tened, are: Length, 13 millimeters and 12 millimeters; width, 21 milli- meters and 17.5 millimeters; convexity, 3.5 millimeters and 4.5 milli- meters. Remarks.—There has been some confusion in the interpretation of this species as it occurs in the Kinderhook and Osage faunas of the Missis- sippi valley and errors have sometimes been made in the identification of the Kinderhook specimens. In its typical form the species occurs in the Burlington limestone, sometimes in enormous numbers, these speci- mens usually having a width of about 15 millimeters or a little more. Where the species occurs more sparingly it often grows to a larger size, sometimes attaining a width of 22 millimeters. In Worthen’s descrip- tion of the species the number of cost are said to be 100 to 120 or more in number, but this number is understated, as about 170 to 190 costz are the usual number upon shells of average size, but upon larger individuals they increase to 225 or more. The actual.number of coste varies with the size of the individual, but the size of the costz is a much more con- stant feature, there being about six in the space of one millimeter, whether the shell be large or small. In Meek and Worthen’s description of the species 12 to 14 costz are said to be present in .10 inch, which would be nearly the number observed on the specimens studied by the writer ; 6 cost in one millimeter would be equivalent to 15 in .10 inch. Winchell’s C. multicosta, with “180-200 fine, subflexuous, radiating strie,” is doubtless synonymous with C. tllinoisensis, and the species would probably never have been described if Hall or Meek and Worthen had stated accurately the number of coste in that species. The specimens in the Chonopectus fauna at Burlington, Iowa, which were referred to C. illinoisensis by the writer,® are probably a distinct species, characterized by its coarser markings, the coste usually being about 110 to 120 in number on an average specimen, about 4 of which occupy the space of one millimeter. The statement in that place that the shells were marked by 120 to 200 coste was based upon observations made in part upon the Burlington limestone specimens. 22s. wv ° Transactions of the Saint Louis Academy of Science, vol. 10, p. 67, pl. 1, fig. 14. yy eae he eh DESCRIPTION OF SPECIES—BRACHIOPODA . 999 Chonetes shumardiana De Kon., with which C. illinotsensis has some- times been compared, has not come under the observation of the writer, but it is a much more finely marked species, with about 12 coste in the space of one millimeter. The specimens in the Fern Glen fauna which are identified as C. illi- noisensis are usually somewhat larger than the average sized specimens in the Burlington limestone, although none of them are as large as the largest of the Burlington specimens. ‘They agree closely with the Bur- lington shells in the size and number of cost and in the general outline of the shell, although they sometimes appear to be proportionally a little wider because of the slight crushing of the shell which has often taken place. CHONETES LOGANI NX. € P. Plate 12, figures 12-13 1855. Chonetes logani N. & P., Journal of the Academy of Natural Science of Philadelphia (2), volume 8, page 30, plate 2, figures 12a-b. 1892. Chonetes logani H. & C., Paleontology of New York, volume 8, part 1, plate 16, figure 25. Description.—Shell small, wider than long, the greatest width along the hinge line, cardinal extremities angular. Pedicle valve strongly con- vex or inflated in the central portion, compressed toward the cardinal angles to form small auriculations, without mesial sinus; surface marked by from 35 to 45 rounded, bifureating coste crossed by raised, concentric markings which are entirely or nearly obsolete in the furrows between the ribs; cardinal area narrow, the cardinal margin marked by two or sometimes three spine bases. Brachial valve deeply concave, following closely the curvature of the opposite valve. The dimensions of an average example are: Width, 11 millimeters; length, 7.5 millimeters; convexity, 4 millimeters. Remarks.—This is not a common species in the Fern Glen fauna, but most of the specimens observed are more or less nearly complete. The species can be easily distinguished from the associated C. illinoisensis by reason of its smaller size, its greater convexity, and its stronger, rugose, radiating costze. PRODUCTUS FERNGLENENSIS n. sp. Plate 12, figures 14-17 Description.—Shell of medium size, a little wider than long, except in very old and much produced individuals, the hinge line a little shorter than the greatest width of the shell, cardinal extremities with small 300 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION auriculations. Pedicle valve gibbous, beak incurved, the median portion of the valve broadly flattened or depressed in a shallow, more or less broad, rather ill defined sinus, the sides abruptly rounding and dropping away almost vertically to the lateral and cardinal margins. Surface of the valve marked by moderately coarse, rounded, longitudinal coste, and on the posterior side by concentric wrinkles, giving to the shell the typical markings of the semireticulate section of the genus; on its an- terior half the shell is marked by the more or less remotely scattered bases of moderately coarse spines, and on the anterior side of each of these spine bases the longitudinal costz of the shell are somewhat fascic- ulate. Brachial valve gently concave posteriorly, becoming flattened toward the cardinal extremities, rather abruptly curved toward the front to conform with the curvature of the opposite valve, elevated along the median line in a low rounded fold. Surface marked by longitudinal coste similar to those of the pedicle valve, and upon the flatter portion of the valve by concentric wrinkles about equal in strength to the longi- tudinal coste. The dimensions of a rather small individual are: Width, 31 milli- meters; length, 28 millimeters; length of hinge line, 25 millimeters; length of shell along the median line, following the curvature of the sur- face, 50 millimeters. Remarks.—This species approaches P. burlingtonensis in its charac- ters and has usually been so identified. It differs from that species, however, in the lower curvature of the pedicle valve, in the less conspic- uous mesial sinus of the same valve, which is broader and shallower in this species and sometimes even obsolete; it also differs in the fascicula- tion of the longitudinal plications in their extension anteriorly from the spine bases. The species resembles P. costatus almost more closely than it does P. burlingtonensis, but may be distinguished by its less con- spicuous auriculations and by the absence of the well defined oblique row of spines which extend from the beak anteriorly at the inner margin of the auriculations of P. costatus, and usually by the less strongly marked surface markings of the shell. PRODUCTUS SAMPSONI n. sp. Plate 12, figures 18-22 Description.—Shell small, as long or longer than wide, rarely a little wider than long, the hinge line shorter than the greatest width of the shell, auriculations small or almost obsolete. Pedicle valve strongly arched, the beak small and strongly incurved beyond the cardinal line, a OEE 8 Nal I Oe eel me Me DESCRIPTION OF SPECIES—-BRACHIOPODA 301 the umbo prominent and projecting considerably back of the hinge line, the median line of the valve prominent from beak to front without median sinus, the sides curving at first more gently and then abruptly to the lateral and cardinal margins. Brachial valve deeply concave, follow- ing rather closely the curvature of the opposite valve and allowing but a small space for the visceral parts of the animal. Surface of both valves marked by rather fine, depressed convex, bifurcating, longitudinal cost which are separated by grooves narrower than the costz themselves ; surface also marked by irregular, concentric, lamellose lines of growth which become more strongly marked on somewhat worn specimens. Spine bases few in number, rather stout, limited to the auricular and lateral portions of the pedicle valve. The dimensions of two individuals are: Length, 12 millimeters and 13.5 millimeters; width, 11.5 millimeters and 14 millimeters; convexity _ of pedicle valve, 6 millimeters and 6 millimeters. Remarks.—In its general form and size this species has some resem- blance to the Upper Devonian Productella hallana Walc., but it is usually a narrower shell, more prominent along the median line of the pedicle valve, and with similar surface markings upon each valve. There is no other species in the Kinderhook faunas which it at all resembles. CAMAROPHORIA BISINUATA (Rowley) ? 1900. Seminula bisinuata Rowley, American Geologist, volume 25, page 263, plate 5, figures 21-24. Rowley has described a small shell from the white cherts of Louisiana, Missouri, as Seminula bisinuata. Specimens of the species from south- western Missouri in the collection of Walker Museum, some of which are internal casts, demonstrate the presence of a distinct median septum in each valve, with a well defined spondylium in the pedicle valve. With such characters the shell can not be placed in the genus Seminula, and it seems more properly to belong to Camarophoria. In the Fern Glen fauna a single example of a much crushed, smooth, rostrate brachiopod shell, with a distinct and strong median fold and sinus in the anterior half of the shell, is placed provisionally in this species. The presence of a median septum is clearly shown in the pedicle valve, and it is probably accompanied with a spondylium; the median septum of the brachial valve is not shown. Before distortion the shell apparently has a length and width of about 10 millimeters each. 302 S. WELLER—FAUNA OF THE FERN GLEN FORMATION CAMAROT@CHIA PERSINUATA (Winchell) Plate 12, figures 24-25 1865. Rhynchonella persinuata Winchell, Proceedings of the Academy of Nat- ural Science of Philadelphia, page 121. : 1901. Camarotechia persinuata Weller, Transactions of the Academy of Sci- ences of Saint Louis, volume 11, page 197, plate 19, figure 5. Description—Shell of medium size, broadly subovate in outline, broader than long, the greatest width at or in front of the middle. Ped- icle valve depressed convex in the umbonal region, the surface rounding rather abruptly to the postero-lateral margins, the median portion de- pressed abruptly anteriorly in a broad, nearly flat mesial sinus which is produced into a broad lingual extension in front at nearly a right angle to the plane of the valve. Brachial valve subpyramidal in form, most prominent near the anterior margin, the surface rounding more abruptly to the antero-lateral margins. Surface of each valve marked by simple, angular or subangular plications, of which usually seven occupy the mesial sinus and eight the fold and about eight or nine each lateral slope of each valve; around the anterior and lateral margins the grooves be- tween the plications are produced into extended, acutely angular ser- rations which fit into corresponding angular notches in the ribs of the opposite valve. | The dimensions of a crushed example of this species are: Length, 16 millimeters; width, 17.5 millimeters. Remarks.—This species is represented in the Fern Glen collections, which have been available for study, only by much crushed individuals. These specimens, however, are clearly identical with this species, which was described by Winchell from the highest Kinderhook bed at Burling- — ton, Lowa, and a part of the characters mentioned in the above description have been taken from an excellent example from Burlington. The shell from Lake valley, New Mexico, which has been described by Miller as Camarophoria occidentalis, is similar to the present species and is, perhaps, identical with it. In neither the description nor the illus- trations of the New Mexican shell are the essential features of the genus Camarophoria indicated, and there need be no hesitation in considering it as congeneric with this Fern Glen shell, even if it is not the same species. SPIRIFER VERNONENSIS Swallow Plate 138, figures 3-8 1860. Spirifer vernonensis Swallow, Transactions of the Academy of Science of Saint Louis, volume 1, page 644. DESCRIPTION OF SPECIES—-BRACHIOPODA 303 Description.—Shell of medium size, subsemicircular in outline, wider than long, the greatest width along the hinge line, cardinal extremities angular or a little rounded. Pedicle valve strongly convex, strongly arched from beak to front, the median line often describing nearly a semicircle; the beak rather small, pointed, and strongly incurved; car- dinal area of moderate height, concave, its ventral margin sharply de- fined, sloping laterally from each side of the beak to the hinge line at the cardinal extremities, the slope becoming more abrupt as it approaches the end of the hinge line; mesial sinus deep, subangular, originating at the point of the beak and widening rapidly to the front, where its anterior portion is often produced into a lingual extension; it is smooth at the beak, but anteriorly it is marked by a single median plication and by eight or ten others which originate through the successive bifurcation of the lateral bounding plications; lateral slopes convex except along the cardinal margin and toward the cardinal extremities, where they become slightly concave. Brachial valve nearly as convex as the pedicle, most elevated at the anterior extremity of the mesial fold; beak small, strongly incurved, cardinal area narrow, becoming attenuate toward the cardinal extremities ; mesial fold depressed in the posterior half of the valve, fre- quently becoming strongly elevated, subcarinate and sometimes slightly recurved toward the anterior margin; it is smooth at the beak, but marked anteriorly by eight or ten plications which originate through the successive bifurcation of the initial median rib; lateral slopes convex except toward the cardinal extremities, where they become somewhat flattened. Lateral slopes of both valves marked by mostly simple, rarely bifurcating, rounded plications, fifteen to twenty-two being present upon each side of the fold and sinus, those toward the cardinal border becom- ing successively smaller; surface also marked by fine, concentric, sub- lamellose lines of growth which become more or less crowded toward the front. The dimensions of a very perfect individual are: Length of pedicle valve from umbo to front margin, 23 millimeters; length of brachial valve, 17.75 millimeters; width of shell, 31 millimeters; thickness, 19 millimeters. The dimensions of a large pedicle valve, in part restored, are: Length, 32.5 millimeters; width, 52 millimeters; convexity, 11 millimeters. Remarks.—Swallow’s type specimens of this species were collected at the locality now known as Fern Glen. The smaller examples of the spe- cies resemble S. marionensis, but they are much more convex in both valves, with a much more elevated mesial fold and impressed sinus ante- riorly. The shape of the cardinal area of the pedicle valve is also differ- 304 S. WELLER—FAUNA OF THE FERN GLEN FORMATION ; ent, the ventral margin sloping laterally toward the cardinal extremities, while in S. marionensis the two margins of the areas are essentially parallel. The manner of growth of the shell of this species is account- — able for the difference in the form of its cardinal area from that of © S. marionensis. The length of the hinge line continues to imerease throughout the entire period of growth of the shell, although as the shell approaches maturity the elongation is proportionally less rapid; at the same time the height of the area is continuously increasing, so that the mature shell possesses the broadly subtriangular cardinal area. Another — feature of this species which can sometimes be detected is the presence ~ of slight crenulations upon the hinge line. The larger individuals ap- proach S. imbrez, of the Burlington limestone, but they are more coarsely — ribbed and exhibit less bifurcation of the plications. SPIRIFER GRIMESI Hall Plate 13, figures 1-2 1858. Spirifer grimesi Hall, Geological Survey of Iowa, volume 1, part 2, page 5 604, plate 14, figures 1-5. | 1895. Spirifer grimesi H. & C., Paleontology of New York, volume 8, part 2 ~ plate 30, figures 8, 16-19. Description.—Shell large, varying from longitudinally to transversely _ subelliptical in outline, the length greater or less than the width, hinge — line shorter than the greatest width, cardinal extremities obtusely angu- — lar or somewhat rounded. Pedicle valve strongly convex; beak rather ~ large, incurved ; cardinal area of moderate width, nearly flat toward the — hinge line, becoming more strongly concave toward the beak, its ventral — margin sharply defined, sloping regularly on each side from the beak © toward the cardinal extremities, the slope becoming much more abrupt — as it approaches the extremities; mesial sinus rather broad and shallow, rounded or more or less angular in the bottom, origimating at the beak, © where it is quite sharply defined, losing its definition anteriorly; lateral ~ slopes convex, becoming more or less flattened toward the cardinal ex- tremities. Brachial valve about as strongly convex as the pedicle; the ~ mesial fold broad, ill defined, becoming more strongly elevated and often somewhat angular toward the anterior margin; lateral slopes convex, — sometimes becoming more or less flattened toward the cardinal extremities. — Surface of each valve marked by eighty or more depressed rounded bifur- cating plications, about twenty or twenty-five of which occupy the fold and sinus. The minute surface markings consist of very fine radiating 4 strie, about six or eight of which occupy each plication, and by still finer concentric strie, giving to the surface of perfectly preserved shells a DESCRIPTION OF SPECIES—BRACHIOPODA 305 finely cancellated ornamentation. A few concentric lines of growth of greater or less strength are usually present toward the anterlor margin of the shell. The -dimensions of a nearly complete example: Length, 56 millimeters ; width, 73 millimeters ; thickness, -- 40 millimeters; length of hinge line, s= 0c millimeters. Remarks.—This is a rather common species in the Fern Glen fauna, but it usually occurs in a more or less fragmentary condition. The Fern Glen examples, however, are entirely similar in size and general characters with similarly preserved specimens of the species from the Burlington limestone where the species typically occurs. SPIRIFER CHOUTHAUENSIS n. sp. Plate 13, figure 11 Description.—Shell suborbicular in outline, the length and breadth nearly equal, the hinge Hne about two-thirds the greatest width of the shell, cardinal extremities rounded. Pedicle valve strongly convex, prominent on the umbo, the beak small, pointed and incurved over the small more or less ill defined concave cardinal area, the lateral slopes concave toward the cardinal line, convex antero-laterally ; sinus of mod- erate depth, continuing to the beak, rounded in the bottom, bounded laterally by rounded plications and marked by from two to four faint, depressed, rounded plications which are formed by the bifurcation once or twice of the lateral bounding plications. Brachial valve less convex than the pedicle, the lateral slopes more or less concave toward the car- _dinal line, convex antero-laterally; mesial -fold convex, becoming more prominent anteriorly, marked by from two to four plications which are formed by the bifurcation of the single initial one at the beak. The lateral slopes of both valves each marked by from ten to twelve simple rounded plications which are separated by rounded furrows of similar width. The dimensions of a specimen of average size are: Length, 19 milli- meters ; width, 21 millimeters; thickness, 15 millimeters; length of hinge line, 15 millimeters. Remarks.—This species closely resembles S. suborbicularis of the Bur- lington limestone except in size. It is in most respects a miniature form of that species, adult individuals not attaining a greater length than 25 millimeters, while S. suborbicularis grows to be two or three times as large, but the plications of this species are less numerous and those of the fold and sinus are less well defined. The larger species of the higher fauna is doubtless genetically derived from this Kinderhook species. 306 S. WELLER—FAUNA OF THE FERN GLEN FORMATION The species is of common occurrence in the Chouteau limestone and has frequently been identified as S. peculiaris, but it may be distinguished from that species by its longer hinge line, its lower and more sharply defined cardinal area on the pedicle valve, and by its more nearly approxi- mate beaks. The types of the species are from the Chouteau limestone of central Missouri and are not illustrated here. The species is an unusual one in the Fern Glen fauna and the example here figured does not exhibit its characters with entire satisfaction. SPIRIFER FERNGLENENSIS n. sp. Plate 13, figures 9-10 Description.—Shell small, subglobular in form, hinge line shorter than the greatest width of the shell, cardinal extremities rounded. Pedicle valve strongly convex, most prominent near the center, the umbo rather small; beak small, incurved; cardinal area small and ill defined, the ven- tral margins rounding into the lateral surfaces of the valve; mesial sinus shallow, rather narrow, rounded in the bottom, originating at the point of the beak, not marked by plications; lateral slopes strongly convex; as they approach the lateral and anterior margins the curvature becomes more abrupt, being nearly vertical in the adult shells, each slope marked by about seven broad, flat, and more or less obscure, simple plications. Brachial valve less convex than the pedicle, most elevated near the center, the mesial fold simple, rounded and not strongly elevated, the lateral slopes convex, curving most abruptly to the cardinal margin, marked by plications similar to those of the opposite valve. The dimensions of a nearly perfect pedicle valve are: Length, 12.5 millimeters; width, 13.5 millimeters; convexity, 5.5 millimeters. Remarks.—This species resembles S. choutcauensis, but is smaller and much more rotund in outline, with the beak of the pedicle valve less prominent and the cardinal area less conspicuous. The dimensions given | above are of an average sized individual; the largest example observed has a length of 15 millimeters. The pedicle valve is most commonly preserved ; only a few distorted brachial valves have been met with. SPIRIFER PLENUS Hall 1858. Spirifer plenus Hall, Geology of Iowa, volume 1, part 2, page 603, plate 13, figures 4a-d. 1895. Spirifer plenus H. & C., Paleontology of New York, volume 8, part 2, plate 37, figures 32-33. Description.—Shell wider than long, but somewhat variable in propor- tions, large individuals becoming more or less subglobose in form; hinge DESCRIPTION OF SPECIES—-BRACHIOPODA 307 line a little shorter than the greatest width of the shell and the cardinal extremities a little rounded. Pedicle valve very prominent in the umbo- nal region, the beak rather blunt and somewhat incurved; mesial sinus originating at the beak, rounded in the bottom, becoming broad and deep anteriorly and in large individuals being much produced in a lingual extension, not sharply defined laterally; lateral slopes of the valve usually convex throughout, but sometimes becoming a little concave toward the cardinal extremities; cardinal area concave, becoming strongly so in large individuals; internally the dental plates are strongly developed and extend well toward the front of the shell; they are conspicuously bilamel- late and cleave readily along their median plane; posteriorly a trans- verse plate connects the dental lamella, its direction being nearly parallel with the cardinal area, but somewhat depressed below the surface of the area. Brachial valve about equally convex with the pedicle, most prom- inent at about its middle point; median fold rounded, becoming strongly elevated toward the front; lateral slopes convex throughout or becoming a little concave toward the cardinal extremities. Surface of the shell marked by rather broad, flattened, simple plications upon the lateral slopes, there being fifteen to twenty upon each side of the fold and sinus on each valve; these plications are progressively smaller toward the car- dinal extremities, the last five or more becoming very obscure; the fold. and sinus are non-plicate; surface of both valves also marked by concen- tric lines of growth which are more or less irregularly developed. The dimensions of two individuals from the Burlington limestone are: Length, 67 millimeters and 50.5 millimeters; width, 81 millimeters and 73 millimeters; length of hinge line, 73 millimeters and 62 millimeters ; thickness, 60 millimeters and 41 millimeters. Remarks.—Spirifer plenus is typically a member of the Burlington limestone fauna, and the above description has been made from examples occurring in that formation. In the Fern Glen formation a single example has been observed which is merely a fragment of the umbonal region of the pedicle valve, showing both the internal and the external surfaces. Interiorly this fragment clearly shows the strong dental plates which are so characteristic of the species and which are so unlike the similar parts of any other associated Spirifer. SPIRIFERINA MAGNICOSTATUS n. sp. Plate 18, figures 12-15 Description.—Shell small, broader than long, with the greatest width along the hinge line, the cardinal extremities often produced into mucro- 308 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION nate extensions. Pedicle valve most prominent on the umbo, somewhat compressed toward the cardinal extremities; beak rather small and in- curved; cardinal area low, concave, the cardinal margin sharply defined ; mesial sinus of moderate depth, rounded in the bottom, bounded later- ally by a pair of strong, rounded ribs which originate at the beak and which are prominently elevated above the plications of the lateral slopes; each lateral slope marked by three or sometimes four clearly recognizable rounded plications beyond those which limit the mesial sinus; they de- crease gradually in size toward the cardinal extremities, and in shells greatly extended along the hinge line one or more additional, exceedingly faint ones may sometimes be detected; the largest of these lateral plica- tions is distinctly smaller than those bounding the mesial sinus; inter- nally the umbonal portion of the pedicle valve is solidified, at least in mature individuals; the diductor muscular impression is strongly de- fined and is divided longitudinally by an angular ridge which becomes more septum-like toward the beak, and which in younger examples with less completely solidified beaks doubtless became a distinct mesial sep- tum. Brachial valve less strongly convex than the pedicle, compressed toward the cardinal extremities; mesial fold but little elevated, rounded, with a faint mesial line which is scarcely a depressed furrow; the fur- rows bounding the mesial fold are somewhat more strongly impressed than the others upon the lateral slopes; the plications on the lateral slopes similar to those of the pedicle valve. Surface of both valves marked by fine, but strong and conspicuous, regular, concentric, sublamellose lines of growth which are distinctly arched toward the beak in passing over the plications of the shell. Punctate shell structure has not been ob- served. The dimensions of a somewhat crushed individual, more than usually extended along the hinge line, are: Length, 7 millimeters; width along hinge line, 24 millimeters; thickness, approximately 6 millimeters. Remarks.—This is a common species in the Fern Glen fauna, but no perfectly preserved examples have been observed. The pedicle valves are much the more common, only three brachial valves having been seen. In many specimens only the central portion of the shell, including the beak, is preserved, and in but few examples is the extension of the sheil along the hinge line shown. In the internal solidification of the beak of the pedicle valve this species resembles 8. solidirostris, but this is a smaller shell, more extended along the hinge line and with fewer plica- tions ; it also lacks the distinct mesial plication of the fold and sinus of that species, and the cardinal area is much smaller. The more dis- tinctive characters of the species seem to be the strong bounding plica- DESCRIPTION OF SPECIES—BRACHIOPODA 309 tions of the sinus of the pedicle valve, the small cardinal area, and the extended hinge line. The shell to which Miller has given the name Spirifera novamexicana from Lake valley, New Mexico, is certainly congeneric with this species from the Fern Glen beds of the Mississippi valley and is a close ally, although the two species are probably distinct. SPIRIFERINA SUBTEXTA White Plate 13, figures 16-19 1862. Spiriferina ? subtexta White, Proceedings of the Boston Society of Nat- ural History, volume 9, page 25. 1901. Spiriferina subtexta Weller, Transactions of the Academy of Science of Saint Louis, volume 11, page 199, plate 20, figures 5-6. Description.—Shell of medium size, wider than long, the hinge line a little shorter than or perhaps sometimes equaling the greatest width of the shell, the cardinal extremities usually, perhaps always, a little rounded. Pedicle valve with a prominent beak which is rather sharplv pointed and moderately incurved; cardinal area rather high, moderately concave, with a narrow delthyrium, not very sharply defined along the cardinal margin; mesial sinus originating at the beak, becoming prom- inent anteriorly and subangular in the bottom; lateral slopes convex, very slightly or not at all compressed toward the cardinal extremities, each marked by from seven to nine rounded plications, including those bounding the mesial sinus, which are successively smaller in passing toward the cardinal extremities; only one or two reach the beak, the others terminating along the cardinal margin. Surface of the shell marked by fine, regular, concentric, sublamellose lines of growth. Shell structure punctate. The dimensions of a nearly perfect pedicle valve are: Width, 15.5 millimeters; length from beak to anterior margin, 10.5 millimeters; height of cardinal area, 3.7 millimeters. Remarks.—This species is represented in the collection by incomplete examples only, the pedicle valves being the best preserved. In the orig- inal description of the species it is said to have “five or six prominent plications on each side of the mesial fold and sinus,” but the Fern Glen examples possess from seven to nine plications upon each lateral slope, although about six are usually all which can be said to be prominent. The species is perhaps most closely allied to S. solidirostris, but it may be distinguished at once by the absence of the median plication of the fold and sinus. It may be distinguished from the associated S. magni- 310 S. WELLER—FAUNA OF THE FERN GLEN FORMATION costata by its larger size, its much larger cardinal area, and its propor- tionately smaller plications. The presence of a median septum in the shell has not been established. CYRTINA BURLINGTONENSIS Rowley Plate 13, figures 20-23 1893. Cyrtina burlingtonensis Rowley, American Geologist, volume 12, page . 308, plate 14, figures 15-17. Description—Shell obliquely subpyramidal in form, the hinge line usually a little shorter than the greatest width of the shell, and the car- dinal extremities rounded. Pedicle valve strongly convex, the beak acu- minate and incurved over the cardinal area; cardinal area high, strongly arched posteriorly, its lateral margins not sharply defined, but rounding regularly into the lateral slopes of the shell; delthyrium narrow, closed by a rather strongly convex pseudo-deltidium which is pierced by a small foramen situated close up under the beak; surface of the valve marked by from three to five rounded plications upon each lateral slope; the two median plications are the larger and extend to the beak; the remaining ones grow successively smaller toward the cardinal extremities and be- come obsolete near the cardinal margin; between the two median plica- tions is a rounded median sinus which originates at the beak. Brachial valve depressed convex, sometimes nearly flat, wider than long, marked by plications similar to those of the pedicle valve; the median plication is the broadest, although it is but slightly elevated above the adjacent lateral ones. In addition to the plications, the surface of each valve is marked by more or less irregular concentric lines of growth. The dimensions of two nearly perfect specimens from the Chouteau limestone are: Width of shell, 13 millimeters and 9.8 millimeters ; length of hinge line, 11.5 millimeters and 7.5 millimeters; length of pedicle valve from front to beak, 13.6 millimeters and 10 millimeters; height of area from hinge line to tip of beak, 5 millimeters and 4 millimeters; length of brachial valve, 9.5 millimeters and 7 millimeters. Remarks—This species was first described from the white cherts at Louisiana, Missouri, but it seems to occur most commonly in the Chou- teau limestone of Pettis county, Missouri. In the Fern Glen fauna a single specimen, a somewhat crushed and distorted pedicle valve, has been observed, but it possesses all the essential specific characters of the Chouteau limestone examples. The species may be distinguishd from other members of the genus with which it might be confused by the rounded instead of angular cardinal margins. DESCRIPTION OF SPECIES—BRACHIOPODA 311 SYRINGOTHYRIS SAMPSONI n. sp. Plate 14, figure 4 Description.—Pedicle valve with an enormously elevated cardinal area whose height is about equal to its width along the hinge line; throughout the greater part of the area its surface is essentially flat, but it becomes a little concave toward the beak; the delthyrium is narrowly triangular, its width at the base being less than one-third its total height; beak pointed, rather small, a little curved; anterior and lateral slopes of the valve poorly preserved in the specimen examined, but a non-plicate median sinus is present which originates at the beak and is apparently rounded in the bottom, becoming profound anteriorly; the markings of the lateral slopes are not well preserved, but doubtless were similar to those of the opposite valve; the cardinal margins between the lateral slopes and the cardinal area are apparently sharply defined. Brachial valve depressed convex, with a median fold which is depressed convex toward the beak, but becomes elevated somewhat strongly toward the front; the lateral slopes marked by simple, rather broad, depressed con- vex plications, of which there are about fifteen on each side of the fold. Surface of the shell marked by minute papille arranged in concentric rows, about seven or eight occupying the space of 1 millimeter; the papille of successive rows are alternate in position, and extending an- teriorly from each is a minute groove which terminates at about the line of the next succeeding row of papille; taken in the aggregate, these grooves give to the surface the appearance of being covered with minute shingles with a papilla at the lower extremity of each. The approximate dimensions of the best example observed are: Length of hinge line, 74 millimeters; height of cardinal area, 57 millimeters; width of delthyrium at hinge line, 16 millimeters; length of brachial valve, 45 millimeters. femarks.—Aside from some fragments too imperfect to show the real characters, this species is represented in the collection by a single exam- ple, which is made the type. The specimen is badly crushed antero- posteriorly, but nearly the entire cardinal area is preserved with but slight distortion. The species may be distinguished from other members of the genus by its proportionately higher cardinal area, it being more nearly approached in this respect hy S. typa. In the proportions of its area the species is most nearly like the European 9. cuspidatus, but in its typical form the area of that species is convex, sometimes strongly so,’ while in the Fern Glen species the area is concave toward the beak. *See Martin: Petrif. Derb., pls. 46-47, figs. 3, 4, 5. 319 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION ATHYRIS LAMELLOSA (L’Eveille) Plate 14, figures 5-6 1835. Spirifer lamellosus L’Eveille, Memoires de la Société Géologique de France, volume 2, page 39, figures 21-23. 1858. Athyris lamellosa Davidson, British Fossil Brachiopoda, volume 2, page 79, plate 16, figure 1; plate 17, figure 6. 3 1875. Athyris lamellosa ? Meek, Paleontology of Ohio, volume 2, page 283, plate 14, figures 6a-b. i 1887. Athyris lamellosa De Koninck, Faune du Calcaire Carbonifére de la Bel- gique, part 6, page 79, plate 21, figures 1-5. 1895. Athyris lamellosa H. & C., Paleontology of New York, volume 8, part 2, plate 46, figures 16-20. Description—Shell transversely subelliptical, the valves moderately and subequally convex, the hinge line short. Pedicle valve obscurely flat- tened along the median line in the posterior half of the shell, the flatten- ing gradually changing into a slight, ill defined mesial sinus anteriorly, the anterior margin of this portion of the shell sometimes being bent toward the opposite valve and produced into a mesial lingual extension of moderate size; beak small, pointed, incurved, and in close contact with the umbo of the brachial valve. Brachial valve slightly flattened along the mesial line posteriorly, the flattening being gradually transformed into an obscure, flattened mesial fold anteriorly, which sometimes be- comes rather prominent near the anterior margin. Surface of both valves marked by parallel, concentric, lamelliform expansions which are commonly in large part destroyed, only their bases being retained. . The dimensions of an average specimen from the Fern Glen fauna, exclusive of the lamelliform expansions, are: Length, 22 millimeters; width, 26.5 millimeters; thickness, 11 millimeters; on the same example the anteriormost lamelliform expansion is produced 11 millimeters and is still not complete. Remarks.—Individuals of this species in the Fern Glen fauna do not usually grow to so great a size as do specimens of the same species in the superjacent Burlington limestone, but in all essential characters the shells seem to be identical with each other and also with European mem- bers of the species. The largest Fern Glen specimen observed, a some- what crushed individual, has a width of 44 millimeters, which is fully as large as some of those in the Burlington limestone. DESCRIPTION OF SPECIES—-BRACHIOPODA 3138 CLEIOTHYRIS ROYSSI (L’Eveille) Plate 14, figures 1-3 1835. Spirifer de royssii L’Eveille, Memoires de la Sociét® Géologique de France, volume 2, page 39, plate 2, figures 18-20. 1859. Athyris royssii Davidson, British Fossil Brachiopoda, volume 2, page 84, plate 18, figures 1-11. 1887. Athyris royssii De Koninck, Faune du Caleaire Carbonifére de la Bel- gique, part 6, page 85, plate 19, figures 19-28. Description.—Shell lenticular, the length somewhat less than the width, the two valves subequally convex. Pedicle valve moderately con- vex, the greatest depth a little posterior to the middle, the surface sloping more abruptly to the cardinal margin; mesial portion of the valve slightly flattened anteriorly and sometimes depressed in a slight, ill defined sinus; the beak small, pointed, in close contact with the umbo of the brachial valve. Brachial valve equally convex or sometimes slightly more convex than the pedicle, the greatest depth near the center, the mesial portion slightly flattened to meet the flattened portion of the pedicle valve. Surface of both valves marked by fine, regular, concen- tric, lamellose lines of growth, which, when the surface characters are perfectly preserved, are produced into rows of close set concentric, imbri- cating fringes of elongate, flattened spines. The dimensions of a nearly perfect individual are: Length, 18 milli- meters ; width, 21 millimeters; thickness, 9.5 millimeters. Remarks.—The name Athyris or Cleiothyris royssii has not always been correctly applied in America. These Fern Glen specimens, how- ever, seem to be certainly specifically identical with this European species as 1t has been interpreted by Davidson and De Koninck. As the shell usually occurs, the concentric fringes of fine spines have been destroyed, so that only concentric, sublamellose markings are preserved, although a few examples have been observed which preserve in part the fringes of spines. ‘The species resembles C. hirsuta Hall, but it grows to a larger size and is proportionally broader. It differs from C. sublamellosa Hall in its more nearly equally convex valves, that species having the brachial valve much more convex than the pedicle, and also in its greater propor- tional width. CLEIOTHYRIS INCRASSATA Hall Plate 14, figures 8-10 1858. Athyris incrassatus Hall, Geology of Iowa, volume 1, part 2, page 600, plate 12, figure 6. 1895. Athyris incrassata H. & C., Paleontology of New York, volume 8, part 2, plate 46, figure 21; plate 83, figure 39. XXVII—BULL. Guou. Soc. Am., Vou. 20, 1908 314 S. WELLER—FAUNA OF THE FERN GLEN FORMATION Description.—Shell biconvex, transversely subelliptical in outline, the hinge line much shorter than the greatest width of the shell, the cardinal extremities rounded. Pedicle valve most prominent on the umbo, the surface curving abruptly to the cardinal margin and more gently to the lateral and antero-lateral margins; the median portion of the shell is depressed in a rounded, ill defined sinus which originates on or just in front of the umbo and becomes profound anteriorly; the curvature of the surface along the median line is strong, the anterior portion of the me- ' dian sinus being directed at nearly a right angle to the plane of the valve; the beak rather small and pointed, incurved, in contact with the umbonal surface of the opposite valve. Brachial valve most prominent along the median line in the anterior half of the shell, where the rounded mesial fold is rather strongly elevated ; lateral slopes convex, most abrupt toward the cardinal and antero-lateral regions of the shell. Surface of both valves, as usually preserved, marked by fine, more or less regular, imbricating lines of growth which are often somewhat wavy along their free margins. When perfectly preserved, these concentric lines were pro- duced throughout as thin, flat spines lying in close apposition to the sur- face of the valve. The dimensions of a somewhat imperfect individual are: Length, 40 millimeters ; breadth, 56 millimeters; thickness, 26 millimeters. Remarks.—As this species sometimes occurs in the somewhat shaly beds of the Fern Glen formation, the nature of its surface markings may be clearly determined, although in no cases have the spinose exten- sions of the concentric lamelle been observed except in small patches. These markings are clearly those of the genus Cleiothyris. As the spe- cles occurs in the superjacent Osage limestones, the surface of the shell is uniformly more or less exfoliated, so that the fine surface details are destroyed. In its general form and surface characters this shell closely resembles Spirifer glabristria Phillips, which is placed among the synonyms of Athyris royssu by Davidson, and it is altogether probable that the Amer- ican and Huropean specimens are members of a single species, although it is not so certain that the glabristria should be included under Cleto- thyrts royssu. CLEIOTHYRIS PROUTI (Swallow) Plate 14, figures 12-15 1860. Spirigera proutii Swallow, Transactions of the Academy of SEE of Saint Louis, volume 1, page 649. 1894. Athyris proutii Keyes, Missouri Geological Survey, volume 5, page 91. Description.—Shell transversely subelliptical in outline, with rounded DESCRIPTION OF SPECIES—-BRACHIOPODA 315 éardinal extremities and a conspicuous mesial fold and sinus. Pedicle valve strongly convex, most prominent posterior to the middle, the sur- face curving strongly from the umbo to the margins, but most abruptly to the cardinal margins; mesial sinus large and deep, rounded in the bottom, defined on each side by a rounded ridge, in old shells produced in front into a lingual extension of greater or less length; beak rather prominent, incurved, in -close contact with the umbo of the opposite valve, pierced by a circular foramen. Brachial valve strongly convex, with a rounded mesial fold which becomes very prominent anteriorly in old shells; lateral slopes of the valve more or less strongly convex, de- pendent upon the age of the individual. Surface of both valves marked — by closely arranged, thin, concentric, imbricating lamelle, which are pro- duced very regularly into fine, flattened spines, the spines of successive concentric rows being arranged in radiating series so that the entire sur- face, even when the spines themselves are in large part destroyed, presents the appearance of being regularly and finely marked in a reticulate manner. The dimensions of two examples are: Length, 17.5 millimeters and 16 millimeters ; width, 22.5 millimeters and 21.5 millimeters; thickness, 15 millimeters and 11 millimeters. Remarks.—This species was originally described from the Fern Glen formation of Saint Louis county, Missouri, and is highly characteristic of the formation wherever it occurs. The species is quite different from any other American athyroid shell, but should be compared with the European Athyris squamigera De Koninck, with which it is possibly specifically identical. In the present paper the species is referred to the genus Cletothyris not because the internal characters of the brachidium have been observed, but because of the character of its surface markings, which most closely resemble those of C. royssi; the concentric fringes of spines in the two species, however, are quite different, the spines of C. royssu being narrower and not being arranged in regular radiating series, as is so conspicuously the case in C. proutit. The shell from Lake Valley, New Mexico, which Miller has described as Spirifera temeraria is clearly a very close ally of Cleiothyris prouti and will probably prove to be specifically identical. PTYCHOSPIRA SEXPLICATA (W. & W.) Plate 14, figure 11 1862. Retzia sexplicata W. & W., Proceedings of the Boston Society of Natural History, volume 8, page 294. 1894. Retzia plicata S. A. M., Eighteenth Report of the Geological Survey of Indiana, page 316, plate 9, figures 24-31, 316 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION 1895. Ptychospira sexplicata H. & C., Paleontology of New York, volume 8, part 2, plate 83, figure 28. 1900. Retzia ? raricosta Rowley, American Geologist, volume 25, page 266, plate 5, figures 34-37. 1904. Ptychospira sexplicata Greger, American Geologist, volume 33, page 15. Description.—Shell subcireular in outline, usually a little wider than long, but sometimes longer than wide, the valves subequally convex; hinge line about one-third as long as the width of the shell, the cardinal extremities rounded. Pedicle valve most prominent on the umbo, the beak rather blunt, slightly incurved, pierced by a small, circular fora- men; cardinal area small, slightly arched, the delthyrium occupying nearly half its breadth along the hinge line; delthyrium closed by a pair of deltidial plates which are frequently destroyed in the specimens; surface of the valve marked by from six to twelve strong, rounded plica- tions which are separated by deep rounded grooves about equal in width to the plications themselves ; the two median plications are the strongest, the lateral ones becoming successively smaller toward the cardinal ex- tremities, the outermost ones sometimes being almost obsolete. Brachial valve more uniformly convex than the pedicle, its most prominent point being near the center; the surface marked by from seven to thirteen strong plications, corresponding with those of the opposite valve. Be- sides the strong plications, the surface of both valves is marked by more or less indistinct concentric lines of growth which sometimes become crowded and conspicuous toward the margin of fully grown shells. The dimensions of two very perfect individuals from the Chouteau limestone of Pettis county, Missouri, are: Length, 9 millimeters and 10 millimeters; width, 10 millimeters and 11 millimeters; thickness, 6.5 millimeters and 5.5 millimeters. Remarks.—This little shell is one of the less common members of the Fern Glen fauna and usually occurs in a more or less crushed and im- perfect condition. The above description has been made from Chouteau limestone specimens from Pettis county, Missouri, where the species occurs in a very perfect condition. The variation of the species consists chiefly in the number of plications upon the shell, those with the larger number being proportionally broader than the others, and in the con- vexity of the valves. fetzia plicata, described by Miller as having from ten to twelve plications, is not specifically different from White and Whitfield’s shell with “only about six plications.” In the Chouteau limestone at Sedaha, Missouri, where Miller’s type specimens were col- lected, examples occur showing the whole range of variation of the spe- cies as regards the number of plications. The most usual number of DESCRIPTION OF SPECIES—-BRACHIOPODA Bl plications seems to be eight on the pedicle valve and nine on the brachial valve, those adjacent to the cardinal line on each valve being rather faint. The convexity of the valves varies considerably, the broader individuals often being much thinner than the narrow ones, as is shown in the dimen- sions of the two individuals given above. eee yt! So tet, | ee tae RETZIA OIRCULARIS 8. A. M.? Plate 12, figure 23 1894. Retzia circularis S. A. M., Highteenth Report of the Geological Survey of Indiana, page 316, plate 9, figures 32-34. Description.—Shell small, subovate in outline, the valves subequally convex, the length and breadth subequal, the greatest breadth at or near the middle, the postero-lateral margins meeting at the beak in nearly a right angle. Pedicle valve with a small, pointed beak, the greatest con- vexity posterior to the middle, the surface rounding to the margin in all directions, but most abruptly toward the cardinal line; along its median line the valve is slightly flattened or sometimes very slightly depressed to form an obscure mesial sinus, the apparent sinus being mostly due to the partial suppression of the median plication; the brachial valve with its greatest convexity posterior to the middle, from which point the sur- face slopes to the margin with a convex curve in all directions, most abruptly posteriorly and postero-laterally ; surface of each valve marked by from twelve to fifteen simple, subangular plications which are about equal in width with the intervening furrows; no concentric markings of the shell are visible. The dimensions of a nearly complete individual are: Length, 5.2 milli- meters ; breadth, 5 millimeters; thickness, 2.5 millimeters. Remarks.—This species is one of the less common members of the Fern Glen fauna. It seems to agree in general form with the specimens of Retzia circularis from the Chouteau limestone of central Missouri, from where that species was originally described, but it differs from au- thentic examples in the partial suppression of the median plication of the pedicle valve, and in the somewhat finer plications of the Fern Glen examples. The internal structures of the species are unknown, but it is not improbable that it should be referred to the genus Ptychospira along with P. sexplicata. 'The shell also resembles Rhynchonella tuta S. A. M., from Lake Valley, New Mexico, but judging from the figures and de- scription alone, it seems to differ from that species in a manner similar to its differences from the authentic examples of Retzia circularis. 318 S. WELLER—FAUNA OF THE FERN GLEN FORMATION DIELASMA FERNGLENENSIS n. sp. Plate 14, figure 7 Description.—Shell large, subovate in outline, narrower posteriorly, the greatest width anterior to the middle of the shell; shell structure finely punctate. Pedicle valve badly crushed in the type specimen, but apparently moderately convex, with a prominent arched beak perforated by a large foramen. Brachial valve probably about as convex as the pedicle. Both valves marked by several moderately strong lines of growth toward the margin. The dimensions of the type specimen are: Length, 55 millimeters; width, 43 millimeters; thickness, probably from 20 to 25 millimeters originally, in the undistorted specimen. Remarks.—This species is represented in the collections by a few frag- mentary or badly crushed and distorted specimens only, so that its char- acters can not be entirely made out. It is characterized, however, by its large size, and differs from other members of the genus of similar size in the Mississippian faunas in its more broadly ovate form and the moderate convexity of the. valves. MOLLUSCA PELECYPODA AVICULOPECTEN FERNGLENENNSNIS n. sp. Plate 15, figure 19 Description.—Shell but slightly oblique, higher than wide, the great- est width near the middle. Body of the shell, exclusive of the auricula- tions, ovate in outline, rather strongly convex in the right valve, which is the only one known. Posterior auriculation depressed convex, sharply defined from the body of the shell, the postero-cardinal angle acute, the posterior margin nearly straight, separated from the posterior margin of the body of the shell by a subangular sinus of moderate depth. Anterior auriculation not preserved, but apparently more sharply separated from the body of the shell than the posterior one. Surface of the shell marked by narrow, sharply angular, radiating coste, which are narrower than the intervening furrows and which are more or less alternating in size; the coste grow regularly smaller in size toward the posterior cardinal extremity and are present upon the posterior auriculation; their charac- ters anteriorly are not known, but they probably also cover the anterior auriculation. Besides the radiating coste, the surface is covered with very fine raised concentric lines, and at intervals by strong, concentric DESCRIPTION OF SPECIES—-PELECYPODA 319 lines of growth which are produced into lamellose extensions, especially toward the cardinal extremities. The dimensions of the type specimen, a right valve, are: Height, 34.5 millimeters; width, approximately 27 millimeters; length of hinge line on posterior side of beak, 12 millimeters; convexity, approximately 6 millimeters. Remarks.—This species is based primarily upon a single incomplete right valve, which does not exhibit all the characters as well as might be desired, and the dimensions given above, in some cases at least, are liable to be in error because of the distortion of the specimen. A fragment of another example, which possibly belongs to the same species, represents a much larger shell with much more strongly developed concentric growth lamellae. The species is characterized by its slight obliquity and by the peculiar character of the surface markings. CONOCARDIUM sp. undet. A few fragments of a shell which seems to be a member of the genus Conocardium have been observed in the Fern Glen fauna, but none of them are perfect enough to allow the species to be identified or described if it is an undescribed form, as is entirely probable. GASTROPODA PLATYCERAS PARALIUS W. & W. Plate 15, figures 17-18 1862. Platyceras paralium W. & W., Proceedings of the Boston Society of Nat- ural History, volume 8, page 302. 1894. Capulus paralius Keyes, Missouri Geological Survey, volume 5, page 174, plate 2, figures la-b. Description——Shell of medium size, more or less carinate, usually closely coiled at the apex through about one somewhat oblique volution, beyond which the body volution becomes free, the sides of the outer volu- tion spreading rather rapidly. Aperture subcircular to subelliptical in outline, but usually subcircular in undistorted shells, the margin more or less denticulate with rounded points and sinuses. Surface of the shell marked by more or less distinct, but sometimes obscure, flattened or de- pressed convex, longitudinal ribs, which are projections of the marginal denticulations and which become more obscure toward the apex of the shell; surface also marked by fine transverse lines, with an occasional stronger line of growth whose direction is parallel with the irregular margin of the shell. ; 320 S. WELLER—FAUNA.OF THE FERN GLEN FORMATION The dimensions of two individuals are: Extreme length of the shell, 34 millimeters and 27.5 millimeters; length of aperture, 22 millimeters and 19 millimeters; width of aperture, 25 millimeters and 21 mill- meters; greatest height of shell, 16 millimeters and 15 millimeters. Remarks.—This is a rather common species in the Fern Glen fauna, and like all members of the genus it exhibits a considerable range of variation because of the sedentary habits of growth. One of the most noticeable variations is in the curvature of the apex of the shell. The normal condition of the apex is as has been described above, but exam- ples are occasionally met with in which the apex is not coiled at all, the shell being a more or less oblique or curved conical shell, such a form probably being assumed from the effect of gravity during the growth of the shell, due to the position of the shell during life. CEPHALOPODA ORTHOCERAS sp. undet. Fragments of a species of Orthoceras are sometimes met with in the Fern Glen fauna. In their present condition they rarely retain more than two or three chambers and are all crushed so as to have a subellip- tical outline, although they were probably originally circular in cross- section. No characters which may be used for specific determination are preserved. CYRTOCERAS ? sp. undet. A single fragment of a curved cephalopod shell has come under obser- vation. Only three chambers are preserved, and these imperfectly. The shell is subelliptical in cross-section, the larger diameter being trans- verse to the plane of curvature; the siphuncle is situated excentrically toward the ventral side. ARTHROPODA TRILOBITA PROETUS FERNGLENENNSIS n. sp. Plate 15, figures 20-22 Description.—Entire body subovate in outline, strongly convex, the greatest width about five-eighths of the total length. Cephalon sub- crescentic, the genal angles produced into conspicuous spines, the mar- cinal border broadly rounded, marked by about four narrow coste sub- parallel with the outer margin; glabella strongly convex, well defined by the dorsal furrows, slightly protuberant in front, the lateral outlines a DESCRIPTION OF SPECIES—GASTROPODA Seale little convex and gently converging in front of the eyes, the anterior margin broadly rounded; glabellar furrows and lobes not well preserved in the type specimen, but a large, strongly convex basal lobe is present, and apparently two lateral furrows on each side which are in close prox- imity to each other and to the furrow bounding the basal lobe; cheeks sloping steeply from the eyes to the marginal furrow, where they are de- flected nearly horizontally into the marginal border; eyes not preserved in the specimen. Thorax with ten segments, the axis more than one- third the width of the body, well defined and strongly convex; proximal portion of the pleura nearly horizontal, the distal half bent abruptly downward at an angle of about 120 degrees. Pygidium rather short, subsemicircular in outline, but not well preserved in the type specimen. The dimensions of the type specimen are: Total length, 55 milli- meters; length of cephalon, approximately 19 millimeters; width of cephalon, 35 millimeters; convexity of cephalon, 13.5 millimeters; con- vexity of thorax, 12 millimeters; length of pygidium, 9 millimeters. Remarks.—The type specimen of this species is a somewhat weathered, complete individual, upon which some of the characters are obscure. A few imperfect pygidia have been observed which probably belong to the same species; also an occasional broken genal spine. The species is per- haps more nearly like P. missouriensis than any other, but that species is proportionately longer, with a glabella which is somewhat broader and subtruncate in front. The coste parallel with the margin in the mar- _ ginal border of the head seem to be a characteristic feature of the species. CORRELATION IN GENERAL In the correlation of the Fern Glen fauna it is necessary to compare it with the faunas of the Chouteau and Burlington limestones, with that of the Saint Joe marble of Arkansas, the New Providence shale of Indi- ana and Kentucky, and the Lake Valley beds of New Mexico. RELATION OF THE FERN GLEN TO THE CHOUTEAU AND BURLINGTON The relations of the Chouteau limestone as a formation have been much misunderstood. The almost universal custom of considering it as the upper member of a threefold classification of all of the Kinderhook beds of the Mississippi Valley region is due to an entirely mistaken in- terpretation. In the region of its typical development in central Mis- sourl, the Chouteau represents the entire Kinderhook interval and is probably contemporaneous in part with the Louisiana limestone of north- 322 S. WELLER—FAUNA OF THE FERN GLEN FORMATION - eastern Missouri, which was being deposited in an entirely separate basin. The so-called Chouteau of northeastern Missouri and Iowa is not the typical Chouteau, and is to be correlated with the highest beds of the Chouteau in central Missouri only. In following the Chouteau lime- stone into southwestern Missouri it is found to occur with its typical lithologic and faunal characters, but much reduced in thickness, near the base of the Kinderhook, and not at the summit, as it is usually repre- sented in geologic sections of that region.* In the Mississippi River sec: tion the same limestone, similar and sometimes identical in its litho- logical characters with the formation at its most typical exposures at Chouteau springs, Missouri, occurs at many localities in Missouri and Illinois. A large fauna has been collected from the formation in Cal- houn county, Illinois, which is identical in every respect with the fauna at Chouteau springs. In the sections where the Fern Glen has its typical development the limestone immediately beneath the red beds is the Chouteau, although in none of these localities has it afforded a char- acteristic fauna or in fact any fauna at all representative. . A discussion of neither the entire fauna of the Chouteau limestone nor any considerable part of it has ever been brought together in one place, and many species in the fauna are as yet undescribed. Further- more, all of the species of the Chouteau of central Missouri should not be considered as constituting a unit fauna, but the zonal distribution of the species should be investigated. Under these circumstances, there- fore, it is impracticable to make a detailed comparison of the Fern Glen with the Chouteau fauna. However, the most characteristic and typical Chouteau species, such as Spirifer peculiaris, Pugnax missouriensis, Reticularia cooperensis, Productella cooperensis, Promacrus nasutus, Triboloceras digonum, and Schizoblastus rocmeri, do not occur in the Fern Glen fauna, nor do they have any close relatives. Among the pre- viously described brachiopods in the Fern Glen, excluding Spirifer ver- nonensis and Cliothyris prouti, which were originally described from this formation, all except one, Cliothyris incrassata, do occur in the upper- most, non-typical beds of the Chouteau of central Missouri, in the Pier- son limestone, which is the equivalent of these beds in southwestern Missouri, and in bed number 7 of the Burlington, Iowa, section, which is immediately subjacent to the Burlington limestone. Several of the more conspicuous brachiopods of the fauna also pass over into the Bur- lington limestone, and some of these are among the most abundant 8 This Upper Kinderhook formation in Green county, Missouri, and elsewhere in the southwestern portion of the state, has been called the Pierson limestone by the writer in Journal of Geology, vol. 9, p. 144. CORRELATION Bye members of the Lower Burlington fauna. Such species are Leptena rhomboidalis, Schizophoria swallovi, Rhipidomella michelinia, Chonetes illinoisensis, Spirifer grimesi, Athyris lamellosa, and Chothyris incras- sata. Other members of the Fern Glen fauna, especially among the erinoids, have close relatives among the Lower Burlington species, and in a few cases are, or seem to be, identical as in the case of Synbathocrinus dentatus, Vasocrinus cf. macropleurus, Metichthyocrinus cf. burlington- ensis, and Calocrinus cf. ventricosus. From the evidence presented, therefore, it 1s clear that while the Fern Glen may still be included in the Kinderhook as a contemporaneous for- mation with the highest, non-typical portion of the Chouteau limestone, it represents the closing stages of the Kinderhook, and in its fauna is foreshadowed the beginning of the succeeding hfe of the Lower Bur- lington. THE SAINT JOE MARBLE The Saint Joe marble is a pink or reddish limestone with a wide dis- tribution in northern Arkansas, lying immediately beneath the Boone chert formation. The color of the Saint Joe is essentially identical with that of the Fern Glen formation in its typical condition, and the more calcareous parts of the Fern Glen are indistinguishable in hand specimens from the Saint Joe. The most complete records of the fauna of the Saint Joe marble have been given by Wilhams.® ‘The identifica- tions in these lists are in some cases now known to be incorrect, but they give a good idea of the composition of the fauna. Faunal lists from eight localities are given which are combined in a single list given below on the left, the number following each name indicating the number of localities from which the species has been recorded in Arkansas. The list on the right, here given, indicates the Fern Glen species which are identical with or represent the Arkansas forms. In a number of cases the same species has been recorded in Arkansas under two or more names; these are indicated in the table by the use of brackets. In the table (page 324) the Fern Glen species mentioned are in every case specifically identical with the corresponding Saint Joe marble forms, except Camarotechia persinuata and Spiriferina subtexta, and these two also are possibly identical. With one exception only, Pugnar acumin- atus, every one of the Saint Joe species not represented in the Fern Glen are either incompletely or questionably identified. The species in the Saint Joe marble which occur in three or more localities are as follows: ® Annual Report of the Arkansas Geological Survey, 1892, vol. 5, Lead and Zinc, pp. 331-334. 324 S. WELLER—-FAUNA OF THE FERN GLEN FORMATION Rhipidomella michelinia, Productus sampsom, Spirifer grimesi, Spirtfer chouteauensis, Spirifer vernonensis, Athyris lamellosa, and Cliothyris proutt. This group of species, with the possible exception of Spirifer chouteauensis, includes by far the most characteristic brachiopods of the Fern Glen fauna, and the lists as a whole show beyond question the elose relationship of the brachiopod elements in the two faunas. Saint Joe marble fauna. Fern Glen representatives. Zaphrentis sp. 1. cf. Zaphrentis tenella Mill. 2. ef. Scaphiocrinus missouriensis Sh. 1. Leptzna rhomboidalis Wilck. 2. Leptena rhomboidalis Wilck. Schizophoria resupinata Mart. ! Schizophoria swallovi Hall Rhipidomella michelinia Lev. 6 | Schizophoria swallovi Hall. Rhipidomella thiemei White ck Rhipidomella michelinia Lev. Rhipidomella vanuxemi Hall - Chonetes ornatus Shum. 1. Chonetes logani N. & P. Productella hallana Wale. 3. Productus sampsoni n. sp. Rhynchonella cooperensis Shum. 2. Camarotechia persinuata (Winch. ). Pugnax acuminatus Mart. 1. | OP Hee ee yey } ae Spirifer grimesi Hall. Spirifer striatiformis Meek Spirifer kinderhookensis te : | Spirifer ovalis Phil. Spirifer chouteauensis ni. sp. Spirifer marionensis Shum. 3. Spirifer vernonensis Swall. Spurifer cf. mesocostalis Hall 1. Spiriferina octoplicata Sow. 1. Spiriferina subtexta White. | Athyris lamellosa Lev. Athyris lamellosa Lev. Athyris hannibalensis Swall. aa Athyris prouti Swall. 3. Cliothyris prouti (Swall. ). Athyris sp. 1. Cliothyris roissyt Lev. 1. Cliothyris roissyt Lev. Ptychospira sexplicata W. & W. 1. Ptychospira serplicata W. & W. cf. Dielasma burlingtonensis White 1. | Capulus equilaterus Hall - Capulus sp. Platyceras paralius W. & W. In the non-brachiopod portion of the Fern Glen fauna there is no form more characteristic than the bases of the bryozoan genus Hvactin- opora, and although the presence of this genus was not recorded by Williams, it has been noticed in abundance by Ulrich.*° The coral and 10 U. S. Geological Survey, Professional Paper no. 24, p. 101. CORRELATION 325 erinoidal elements in the Saint Joe fauna are essentially unknown, but forms similar to those in the Fern Glen may be looked for. The exact correlation of the Fern Glen with some part of the Saint Joe formation as it was interpreted by the members of the late Geo- logical Survey of Arkansas may be assumed to be established. Unpub- lished data gathered by Dr E. O. Ulrich, however, suggest that a lower member, perhaps separated by a slight unconformity from the typical Saint Joe marble, was not sufficiently differentiated by the members of the Arkansas Survey. These lower beds are commonly fossiliferous, while good fossils are comparatively rare in the Saint Joe proper, and it is from these lower beds that most, if not all, of the material recorded by Williams was probably obtained. The exact correlation of the Fern Glen beds, therefore, will probably prove to be with these beds which are immediately subjacent to the typical Saint Joe marble, but which have been commonly united with that formation as a single formation unit. THE NEW PROVIDENCE SHALE The name New Providence shale was first applied many years ago to the basal portion of the so-called Knobstone group in southern Indiana by Borden,’! and has been revived more recently by Newsom.? The formation includes from 50 to 120 feet of shales‘ which immediately overlie the Rockford goniatite limestone, which carries a fauna with strong Chouteau affinities. ‘The fauna of the New Providence shales in Indiana has been made known in an inadequate manner, the list fur- nished by Newsom’* being incomplete and having some of the identrfica- tions probably incorrect. The same formation extends into Kentucky, and a locality at Button Mould knob, south of Louisville, has been mentioned not infrequently by the older collectors of fossils from that region. A small collection of material from this locality has been available for study by the writer, which shows the fauna to be rich in small corals, among which are sey- eral species of Cyathaxonia, including C. cynodon K. & H., which was apparently originally described from this or a neighboring locality. This genus is one of the most common in the Fern Glen fauna, and although the species in the two localities seem to be different, they are somewhat closely allied. Among the other corals, the species described in the pres- ent paper as Amplexus rugosus is represented in the Button Mould Knob fauna by perfectly typical examples, and Monilopora crassa is also com- 4 Fifth Annual Report of the Geological Survey of Indiana, p. 161. 1 Twenty-sixth Annual Report of the Geological Survey of Indiana, p. 261. 18 Loc. cit., p. 278. 326 S. WELLER—FAUNA OF THE FERN GLEN FORMATION mon in the Kentucky locality. Several species of Zaphrentis which aré not identical with, but are allied to, those of the Fern Glen fauna are present in the fauna. Aside from the corals, only a single species of brachiopod is contained in the collection, Rhipidomella owem H. & C., which is a close ally and is perhaps not distinct from R. michelima, the most abundant brachiopod in the Fern Glen fauna. The only blastoid recognized in the Fern Glen fauna is Pentremites decussatus, a species which was originally described from Button Mould knob, and an exam- ination of the type specimen in the collection of Mr Frank Springer has shown the identification of the Fern Glen specimens to be correct. Although our knowledge of this basal Knobstone fauna is incomplete, the evidence available seems to indicate that a reasonably cle correla- tion between it and the Fern Glen fauna can be made. THE LAKE VALLEY BEDS" A highly interesting Lower Mississippian fauna has been described by Miller® and by Springer’® from Lake Valley, New Mexico. The list of species given by Springer is much more complete than that of Miller, but both lists need revision, in the light of the more recent investigation of the Mississippian faunas of the Mississippi valley. Any comparison of the fauna with that of the Fern Glen beds is entirely inadequate, in the absence of actual collections for study, but some suggestive observa- tions may be made from the published lists alone. The crinoids of the fauna, which constitute a very considerable ele- ment, point strongly to its Lower Burlington age. Springer says: “Every one of the species named belongs to the Lower Burlington (leaving out A. copei, which was described from Lake valley), and the new species are of the same types. Not a single species has been discovered that is peculiar to the Upper Burlington or any other group of the Subcarboniferous.” This same statement would be perfectly applicable to the crinoid fauna of the Fern Glen formation, as all of the previously known species occur in the Lower Burlington, and the new species are members of genera which are present in the same fauna and are mostly more or less closely allied to previously known species of that horizon. Among the brachiopods in the fauna, such species as A thyris lamellosa, Schizophoria swallovi, Leptena rhomboidalis, Rhipidomella michelinia, 14 Since this paper was written a collection of Lake Valley fossils has come into the hands of the writer through the generosity of Mr Frank Springer. Examination of this collection has confirmed and very much strengthened the supposed similarity of the fauna with that of the Fern Glen formation. 15 Journal of the Cincinnati Society of Natural History, vol. 4, pp. 306-315, pl. 7. 16 American Journal of Science (3), vol. 27, pp. 97-103. ee BULL. GEOL. SOC. AM. FERN GLEN FAUNA VOL. 20, 1908, PL. 10 CORRELATION 327 etcetera, are abundant in the Fern Glen. The species which is described by Miller as Spirifera temeraria is clearly identical with Cliothyris proutt, which is one of the most characteristic species in the Fern Glen fauna and which does not occur in the superjacent Burlington at all. Although a really critical comparison of the Lake Valley and Fern Glen faunas must await an opportunity to study the Lake Valley collec- tions, yet the comparison which is possible from the literature alone sug- gests a rather close correlation of the two. DESCRIPTION OF PLATES PLATE 10 RE COSIVCSMUGUINGCYUETCHSIS TM SPi. occ o'sic cc eke ec ce ne cere eeweecens page 274 Figure 1. View of the largest corallum observed. Figure 2. Longitudinal section of a corallum of average size. MOM MONLETICUING TW. SDisise ss ssc cece ss ose ses sateen eaves onsen. page 274 Figures 3-4. Two views of the type specimen. PT TAC TSMOLCMCSSIUS NL. &o Wrasse vis ois .c%0 0 ce ie are sie aie eoalien 0 6 oe aleis eres oi e's page 276 Figure 5. Vertical view of a four-celled specimen. Figures 6-7. Vertical and lateral views of a three-celled specimen. CE eM IIPIDUSHEMe. (S])iie0 s, cvcie ye Ae pes eG weg vier she ad aie 0.4 Stele eyeveld’s @ ware wa bee's page 277 Figure 8. Lateral view of one of the type specimens. Figures 9-11. Two lateral views and a vertical view of another of the type specimens (collection of F. A. Sampson). A LOR TOMInCMOUCS: IN. (SPici. als wind cee ware velele ers cab cece sess eee seas page 269 Figure 12. Lateral view of a large example. Figure 13. View of another specimen showing the calyx and col- umella. PMOL O MER HOIOG- WW. SDs. ssc s avivie cies ce eessseveeicuseeevesscecesss page 270 Figures 14-17. Lateral views of four different individuals. ME RCuISmG TOTOONG Hy. & TN. occ iw eke eee See tn was seecenacsces page 272 Figure 18. Lateral view showing the curvature. Figure 19. View of another example showing the calyx. MCU ReISMILORUMCIVE Tei SYs sc «ie diei ova ee comes s voice cu al elewiee ewes ee dels page 273 Figure 20. Lateral view of a specimen showing the amount of curva- ture. Figure 21. View of another example looking into the calyx. RR ER ETE SMELL (LOS LUSUINS* SIDs city, aro teee ne ane! slo lefiolla, spiayiar'st dvohei Ble; @. srwceisiw «thts toreversesters page 271 Figures 22, 24-25. Views of three different individuals. Figure 23. Longitudinal section of a fourth example. LESS HIRZBUS TIDE ESS Opes tic MOE ene eae Ne ie = 2 page 271 Figures 26-29. Views of four different examples. Cladoconus americanus n. Sp.........-ee.e0e- Bad OOM CRE Conn ROTC Ee page 275 Yigure 30. View of the type specimen. mre TeTOSSO (NCOOY) se5 oe aoc oa ere cin cc viele ov sccsicie Cars veie vs ete es page 275 Figures 31-32. Two views of the same colony. Figure 33. View of another colony. 328 S$. WELLER—FAUNA OF THE FERN GLEN FORMATION PLATE 11 Physetocrinus smatieyi. No USP... cs 2 vo ose oe 2 2s 3 eS ee page Figures 1-3. Lateral, dorsal, and ventral views of the type specimen (collection of F. A. Sampson). ACHINOCTINUS -TUBTA. TN. SPer sv xe ess so o.0 0's ee «oo Soe ore we oe le page Figures 4-5. Lateral and dorsal views of the type specimen. The lat- eral view is from the right anterior side, which is abnormal in having but one costal plate (collection of F. A. Sampson). Lobocrinus pistilliformis (M. & W.) Figure 6. Lateral view of the type specimen (after Meek and Wor- then). Agaricocrinus preeursor Rowley... .-- 265.22. - + ese 9 oo ce ....page Figures 7-9. Dorsal, ventral, and posterior views of a nearly perfect specimen. Figures 10-12. Dorsal, ventral, and anterior views of another speci- men (both specimens from collection of F. A. Samp- son). Platycrinus stellatus De. SP... sce oe ot oo ee sce See eee ee page Figures 138-14. Lateral and ventral views of the type specimen (col- lection of F. A. Sampson). Rhodocrinus punctatus Wi SP... . seek ce ee one ee ae sae 0 er page Figures 15-16. Lateral and basal views of the type specimen. Platycrinus springert OSD... Sp:ac.s spp oee C ae eee eee ee ere page 306 Figures 9-10. Ventral and lateral views of a ventral valve. Spirifer chouteauensis . SP...2 4. 2s0s sees oes os 5 oe ele ee See page 305 Figure 11. Dorsal view of a somewhat crushed specimen. Spirtferina magnicostata nN. SP.cact.e silse se ose eesne eek ase ee eee page 307 ‘Figures 12, 13,15. Views of three incomplete ventral valves. Figure 14. Posterior view of a distorted specimen. Spiriferina subtecta White...........2100+ee++ssu0<) ss page 309 Figures 16-18. Ventral, anterior, and posterior views of a perfect ven- tral valve. Figure 19. View of a dorsal valve. Cyrtina burlingtonensis Rowley ...........2.0..-c--+euseese eee -page 310 Figures 20-22. Ventral, dorsal, and lateral views of a perfect speci- men (from Chouteau limestone, Pettis county, Mis- souri). Figure 23. View of an imperfect ventral valve from Fern Glen. VOL; 20, FOS, ka 18 BULL. GEOL. SOC. AM. e FERN GLEN FAUNA VOL. 20, 1908, PL. 14 BULL. GEOL. SOC. AM. FERN GLEN FAUNA =i DESCRIPTION OF PLATES PLATE 14 EDEMA ITTSATOUSSE (la HAVCLULE) pierces te aiege oe esos 2 wore 0% sienreves oo ow ne ea ees page Figures 1-3. Ventral, dorsal, and lateral views of a perfect specimen. MOOI UEAS SON DSONL. We. Sha dose vic wale osc ncic ssa cae ee cee oasis ae page Figure 4. Posterior view of an imperfect specimen. PSOE LIOSG, CU MIVENIE). 2. ike sleek acca ee ete ewe cence eee page Figure 5. Ventral view of a nearly complete specimen. Figure 6. Ventral view of a specimen retaining some of the expan- sions of the shell. EMM MRC IIVOLCIVCIUSTS, Te SJ) isso seco ate ous oe nmsene aie soierel © ss) e 5 0c tals cieleicies ace page Figure 7. Dorsal view of a distorted specimen. ISTHE ASSOTUS. ELAM. coco c os co os clea lenis uvcteecesseccceues page Figure 8. Ventral view of a large specimen. Figures 9-10. Ventral and dorsal views of an incomplete specimen. eS PT SOL OUCH (WV. Si: Wao)ec-e ccs scctewec ede dec sees eb owcens page Figure 11. Ventral view of a perfect specimen (from the Chouteau limestone, Pettis county, Missouri). ERMC E TOIT: “CSW ALLOW)... sae sales da cw ence dae eo slaSiececcseeeees page Figures 12-15. Ventral, dorsal, anterior, and lateral views of a nearly . perfect specimen, d0L 313 311 312 318 313 315 314 332 S. WELLER—FAUNA OF THE FERN GLEN FORMATION PLATE 15 Fistulipora. fernglenensis NM. -SPi sas «2. a6 60s 02 esses seen ne page 289 Figures 1-2. Upper and lower views of an elliptical zoarium. Chilotrypa americana.S. A. Mi .. desc oa sic ce viele cone ees page 290 Cystodictya lineata Ulriehi <2. se wens cnc « oem pee me ee ee page 290 — Figure 3. Lateral view of a fragment of a zoarium with the largest diameter observed. Hvactinopora serradiata M. & W...2.2+ scene eee eee eee eee page 291 Figure 4. View of a fragment of a zoarium. ; Platyceras poralius W.. & Woe. ov~-0.00 5 60s be bac eas eae se ee page 319 Figures 5-16. Views of twelve different bases, showing the variation in number of rays. Figure 17. Lateral view of a nearly complete shell. Figure 18. Dorsal view of another specimen. Aviculopecten. fernglenensiS. ND. Sp...<...+.ceeres-s «sess ee eee page 318 Figure 19. View of the type specimen. Proetius ferTnglenensis M2 Spy ieee eee eee oe Pry ri fos: page 329 Figures 20-21. Dorsal and lateral views of a nearly perfect specimen. Figure 22, An incomplete genal spine. ~ BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 15 FERN GLEN FAUNA BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 333-340 SEPTEMBER 15, 1909 a SHORTAGE OF COAL IN THE NORTHERN APPALACHIAN COAL FIELD? (Presented before the Society December 31, 1908) BY FT. CC: WHITE CONTENTS Page ERNE TIMEAUIGE Aiea deer tefelent Sirer ciel eheke. cones the miei iai aisle fae wilcc ee tos, b 0.8 eee faa, a alews 333 Smxtent of reduction Of the productive areas... . 1... cee weer cease nee eee 334 fecniad: Of deposition: OF the COAL]. ..5. 6. cc ce ck ce ween ee ere ene aws 335 Moracion of. the northern Appalachian field... ... 2.0.6... cece cece eee 339 a AMM SEL SHE MO CULO Ny ous scores, sha aoe. oo 8. Seats 6 esi sila is, dlc) MW ee © eles a vier wate ued ae 336 eee EO Teme DteUS TOTS ina sors alec e afb, che) a a 6 Lowi eleve oye BUS eels sleiccsre wie So8ls epoca a geil oot ETE MMEONIE STV CP ETON gcse close c's o areteve sei wis cle sop Sielec a dese 2 mad ee se Skewes sb 338 EMC eROrs THe CVIIS OF WASTE. . 6. dl. hee eee enews ontee wees peers 339 THE BARREN AREA It was formerly supposed that the several coal formations of the Appa- lachian region would hold coal of commercial value over the entire area of that great field. Your speaker pointed out, many years ago, that this was a grave mistake, so far as the Monongahela and Pottsville series are concerned, and, later, that the Allegheny and Kanawha coals also share the same. fate when they pass under water level toward the center of the Appalachian basin; that, instead of a continuous sheet of productive Coal Measures underlying this entire field, there is a great barren zone which in the Allegheny series begins a few miles north from Pittsburg, and, embracing most of Allegheny county, a large portion of Westmore- land, practically all of Washington, Greene, and western Fayette, as weil as southern Beaver, passes southwestward entirely across West Virginia and southeastern Ohio, thus reducing enormously the productive area of the Allegheny series and its usually estimated coal resources. The celebrated Pittsburg coal holds its place in the series, however, until we reach Doddridge county, western Wetzel, and eastern Tyler, in West Virginia, when it, too, disappears, except in scattered patches along its eastern crop through Lewis, Braxton, Gilmer, Roane, Kanawha, and 1 Manuscript received by the Secretary of the Society August 28, 1909. ‘This paper was also presented before the American Mining Congress in December, 1908, under the title ‘““‘The Barren Zone of the Northern Appalachian Coal Field.” XXIX—BULL. Grou. Soc. AM., Vou. 20, 1908 (333) 334 I. Cc. WHITE—SHORTAGE OF COAL IN APPALACHIAN FIELD Putnam counties, as we may see by inspection of the coal map of the West Virginia Geological Survey. The same thing happens to this coal in southeastern Ohio, so that it is practically absent from Monroe, Wash- ington, eastern Athens, much of Meigs, and Gallia. These facts have been brought to light principally by the oil-well drill- ers in the search for petroleum and natural gas. The great Burning Springs-Voleano anticlinal of West Virginia, which along its highest crest in Wirt, Wood, and Pleasants counties brings up to daylight suc- cessively the Monongahela, Conemaugh, and Allegheny series, right across the center of the Appalachian field, confirms the story of the drill, since near Petroleum station, where all the measures from the top of the Monongahela series down to the Pottsville are exposed to view, only one coal bed is visible, and it is only four feet thick, impure, and split into two practically worthless divisions by 6 to 8 feet of slate. Your speaker has personally examined the rock materials brought up by the sand pump while the drill was passing through the Allegheny beds in several wells from the region of Pittsburg southwestward across western Pennsylvania, West Virginia, southeastern Ohio, and on to the Big Sandy river at the Kentucky line in Wayne county, with the result that over a belt having a width of 40 to 50 miles at the Pittsburg end, and practically the same on the Big Sandy, and swelling out to 100 miles or more near its center at the longitude of the Little Kanawha river, there is practically no com- mercial coal, as we know that term now, in the entire Allegheny series. EXTENT OF REDUCTION OF THE PRODUCTIVE AREAS The effect of this barren zone on West Virginia’s productive coal area is to reduce it from 17,000 square miles, as usually given in statistical tables, to only about half that size, and the tonnage, as recently estimated by Mr M. R. Campbell, of the United States Geological Survey, from - 231,000,000,000 to only about 60,000,000,000 tons of first-class available fuel, after providing for the necessary waste in mining, or less than one- half of Mr Campbell’s estimate for that state. The 112,000,000,000 tons of bituminous coal originally existing in Pennsylvania and 86,000,000,000 in Ohio, as estimated by Campbell, are also both much too great, on account of this barren zone in these states. It is quite certain that Pennsylvania will not furnish much more than 40,000,000,000 tons and Ohio probably not more than 25,000,000,000 tons of commercial bituminous coal; so that the three great coal states of the northern Appalachian field, namely, Pennsylvania, Ohio, and West Virginia, will together produce only about 125,000,000,000 tons of good coal and probably 50,000,000,000 tons of an inferior grade, instead of the much larger quantity indicated by Mr Campbell’s figures, which are evi- DEPOSITION OF THE COAL 335 dently based upon the old supposition that this barren area would hold as much coal as any other portion of the Appalachian field. MertTHOoD OF DEPOSITION OF THE COAL From this brief statement of the facts in the case it would appear that the several coal formations, beginning with the oldest—Pocahontas, New River, Kanawha, Allegheny, Conemaugh, and Monongahela—were depos- ited in narrow belts or fringes, 20 to 30 miles in breadth, around the bor- ders of the great Appalachian basin, each higher series extending farther toward the center of the trough than its predecessor. This condition of affairs is shown by the distribution of the colors on the West Virginia coal map, and which in its uncolored portion also indicates the central barren zone. ‘The query naturally arises: Why were no valuable coal beds formed in this great central trough, where the older geologists and many of the younger ones, it appears, supposed the coal beds would be thickest and most numerous? ‘The question is a puzzling one, but this absence of valuable coal deposits is due most probably to the fact that the central region of the Appalachian coal field was covered with water to such a depth that vegetation could not secure a foothold, and hence while sediments accumulated there to practically the same thickness as in other portions of the basin, they consist only of shales, sandstones, and lime- stones, the latter being in greater proportion than where the coal accumu- lated in commercial quantity. Of course, there will be some islands of commercial coal in this long and broad barren zone, but they will be local and of small extent. DURATION OF THE NORTHERN APPALACHIAN FIELD This shortage of coal brings to the citizens of the Pittsburg region, the present manufacturing center of the world, the most serious problem that has ever confronted them. ‘They have been told that they originally had 430,000,000,000 tons of coal in the three states that surround them, and that it would suffice for 150 to 200 years, while the truth is they have only about one-half of that amount, and with the present wasteful mining methods it will last only 50 years. If this waste continues, some of you in this audience will see the finish in the northern Appalachian field of all cheap and easily obtained coal. Many of you do not credit these statements. ‘They are capable of demonstration to those whose minds are open to reason and the irresistible logic of facts. The area of the great Pittsburg bed, that wonderful coal seam to which Pittsburg owes its very existence, is known almost to the acre. Pennsyl- vania had remaining 1,090,000 acres of it at the beginning of 1908, and she has several thousand acres less now, since her annual production from this one coal bed is approximately 95,000,000 tons. This represents an 336 =. Cc. WHITE—SHORTAGE OF COAL IN APPALACHIAN FIELD exhaustion of over 1,000 acres every month of the year, because the best mining engineers of Pennsylvania have succeeded in saving and utilizing only 8,000 tons of coal to the acre, of the 12,000 to 15,000 that are pres- ent in the Pittsburg vein. Hence, should there be no increase in produe- tion over the present, this famous coal bed would be entirely exhausted from the state of Pennsylvania within 80 to 90 years. But what reason is there for not believing that every normal year will record its regular increase, until in 10 to 12 years at most Pennsylvania will have doubled her present output of Pittsburg coal? West Virginia has only about the same acreage of this great coal bed as Pennsylvania, while Ohio’s entire area will be practically gone in 25 years. Hence one can readily perceive that, with only a century’s supply at the present rate of mining and in view of the greatly increased production which can not fail to come with our growth in population, 50 years is a liberal estimate for the life of the Pittsburg coal bed. The same causes will in approximately that time exhaust all of the cheaply mined thin veins in the Allegheny series of — Pennsylvania, Ohio, and northern West Virginia, and Pittsburg’s indus- tries will have entered upon the expensive method of mining coal by deep — shafts to beds of inferior quality, of only one to two feet in thickness, — and of attempting to recover at great expense the many millions of tons — of good fuel already left in the pillars, roofs, and bottoms of long aban- doned mines. This is no fairy story. It is as sure to come to pass at approximately 50 years in the future, if present wasteful methods con- tinue, as that the sun will rise tomorrow. cy 6 lie nlp! Pe Ee hi thy, ee eg mln: Siig SN teen: A ili ally Dak, D es oe. eB & ‘ae * PRESENT WASTE OF FUEL It can do no harm to recall some of the sins of waste committed in the © past, since many of these still persist. The citizens of Pennsylvania, and - especially of the Pittsburg district, have already wasted more of their precious fuel supplies, both solid and gaseous, than they have ever used. — More than thirty thousand beehive ovens continue to consume, almost within sight of their great factories, one-third of the power and all of the precious by-products locked up in the finest bed of coal the world has ever known, and of which, as we have seen, they have such a limited supply. — The quantity of natural gas, that best of all the fuels, which western Pennsylvania has wasted from the many thousands of wells drilled within her borders, vastly exceeds in value all the petroleum she has ever Pro- duced. Not satisfied with thus despoiling their own fair commonwealth — of its most precious fuel possession, some of the most powerful corpora- tions, with headquarters in Pittsburg, have been the principal agents in — wasting unnumbered billions of cubic feet of this precious fuel in the sister states of Ohio and West Virginia. The general superintendent of — one of the great gas companies told me only a few days ago that he had OF es hi ee. Bideines sz . PRESENT WASTAGE ~ 337 personal knowledge of one well in West Virginia from which 12,000,000 feet of gas escaped daily in producing only four barrels of oil, and this spectacle of wasting the heating value of 12,000 bushels of coal daily, together with the power to deliver itself free of charges for transportation to Pittsburg’s factories, was at that time not an isolated case, but only one of hundreds. During this riot of waste one of these great gas com- panies put into its lines in West Virginia nearly 100,000,000 cubic feet of gas daily and delivered in Pittsburg much less than half that quantity, the larger portion having escaped into the air through the defective joints of cheap and imperfect pipe-line construction. An enormous waste of gaseous fuel is still an incident of oil production in Pennsylvania, os _ well as in Ohio and West Virginia, and will probably so continue to the end of the chapter, largely because a few influential citizens of Pennsy!- vania, Ohio, and New York always oppose any attempt to prevent this crime against these commonwealths. A great portion of this wasted gas in West Virginia and Ohio was safely stored by nature, under immense pressure, in the immediate pathway of this barren coal zone, and there ean be no doubt that its heating value, if properly utilized, would have much more than replaced the missing coal beds, and thus to that extent delayed the end of cheap fuel in the Pittsburg district. DANGER OF CATASTROPHES The recent awful catastrophe at Marianna is most disquieting to think- ing minds. Disquieting, not alone for the frightful loss of precious lives from the ranks of the brave toilers in a most dangerous occupation, in which the men of skill are all too few, but also for the dread suspicion which arises concerning the future of deep mining in this richest zone of coal. Harwick, Ellsworth, Naomi, Monongah, Darr, Marianna are all within the regions of great deposits of natural gas. Can it be possible that in such situations this volatile substance, released from its long prison by the thousands of oil and gas wells drilled to the deeply buried reservoirs of gaseous fuel, has permeated these mines in large quantity through the ever-present fissures of the earth’s stony crust? At the White House conference of governors, called last May by our illustrious President to take stock of the fast disappearing natural re- sources of the nation, and to advise with him concerning ways and means to conserve the same, your speaker called attention to this “sword of Damocles,” an ever-impending peril to deep mining over the oil and gas areas, and to the unknown waste of coal and precious lives that may pos- sibly result therefrom. At least three-fourths of the entire area of Pitts- burg coal remaining unmined in Pennsylvania, Ohio, and West Virginia is within this dangerous zone. Of the thousands of oil and gas wells drilled in this great area stretching from the Pittsburg region southwest- 338 I.C. WHITE—SHORTAGE OF COAL IN APPALACHIAN FIELD ward across Pennsylvania, West Virginia, and southeastern Ohio, hun- dreds of which have been abandoned in each of these three states and the casing removed, probably not a single one has been so located by public charts accessible to coal operators that its presence could be learned and its danger guarded against after the farmers have cleared away the rub- bish of derrick and drill and recovered the poisoned soil for grazing or other agricultural purposes. ‘There would have been perils enough in this deeply buried Pittsburg coal area from the inflammable gases already present in the coal itself, if not a single oil or gas well had ever been drilled to these great underlying reservoirs to release, when abandoned, the deadly forces of explosive gas into the very midst of the workers, against which neither the skill of the miner nor the science of the engi- - neer seems able to cope. It is barely possible that the oil and gas pro- ducers have thus through abandoned wells added so greatly to the perils of deep mining that large areas of this matchless Pittsburg coal, as well as any other beds which might underlie it in this broad oil and gas belt southwest from Pittsburg, will be practically irrecoverable except at enor- mous expense of life and treasure. It is needless to comment upon the additional fuel shortage which such a condition would mean to Pitts- burg’s iron and steel industries. ‘The mere mention of the possibility of this peril ought to be sufficient to put every patriotic citizen on guard against increasing this danger. Not a single string of casing that has penetrated the productive coal measures in the oil or gas regions of the states where natural gas is encountered in any appreciable quantity should ever be pulled out until the underlying coal has been removed. The oil producers are robbing the entire country of its precious fuel gases. Why should they be permitted also to endanger its solid fuels? Here is some work for the governors and legislatures of Pennsylvania, Ohio, West Virginia, and Kentucky that could bring no harm to legitimate oil and gas interests and which may result in an immense saving of life as well as of fuel resources. NEED OF CONSERVATION What moral should be drawn from these facts? That homely adage of our forefathers, “Needless waste brings woeful want,” is just as true for communities, states, and nations as for individuals. The story of “Coal Oil Johnny” is being reenacted by the Pittsburg district and many other districts of our country on an enormous scale, and the final results, although a little longer delayed, can not fail to be similar. On the one hand we perceive our fuel resources reduced by this barren zone to one- half of what were supposed to be readily and cheaply accessible, and on the other, these resources so greatly depleted by unbridled waste that in NEED OF CONSERVATION 339 only a few years at most cheap fuel will have passed into history from this great district. Disguise it as we may, the picture is not a pleasing one. The great engineers and captains of industry, whose skill and genius, aided by an unrivaled wealth of cheap fuel and the protecting egis of a wise and gen- erous government, have centered here the iron and steel business of the world, should not glance at the picture and turn lightly away to forget it in the busy hum of furnace and forge. These wonderful industries should remain here and prosper not a few decades, but for centuries. But just as surely as the successful past and glorious present have been founded upon unrivaled resources in cheap fuel, so surely will these great industries decline and die with its disappearance. ‘“Mene, Mene, 'Tekel, Upharsin” will be written large over the gateways of the Pittsburg dis- trict before the present century closes, unless the men who own the mines and factories awake at once to the danger that portends. What will it profit these industries that enormous coal deposits exist in Wyoming, North Dakota, Montana, and far away Alaska, as well as in other portions of the distant west, when a freight cost of many dollars per ton intervenes? No, these western coal fields are not for Pittsburg. Nature has forbidden it by barriers which the skill of man can never hope to conquer. When the coal in the Appalachian field is gone, no other field can take its place in Pittsburg’s industrial life. Every citizen of our beloved union is interested in perpetuating as long as possible the giant industries that have sprung into existence around the home of Father Pitt. When the mighty pulsations of this industrial life slow down even temporarily, lethargy and palsy strike every artery of trade and commerce on the continent. The postponement or preven- tion of the evil day when these great industries shall close for want of power is worthy of the best thought of every patriotic American. REMEDY FOR THE EVILS OF WASTE What is the remedy? What is possible to be done in order to postpone indefinitely this dreaded day, so fateful to industrial life? The answer may be summed up in two words—Stop wastes. Not alone waste of nat- ural gas, waste in mining, but all other needless wastes. Why should the flaming throats of so many wasteful coke ovens continue to vomit sky- ward such enormous volumes of precious gaseous fuel, with its clouds of carbon to pollute the air, stifle vegetation, and render life a burden, when all of this wasted energy will so soon be needed in our unrivaled fac- tories? ‘True, your furnace managers may say the coke from the beehive oven is superior in structure and reducing capacity to that of the by- product process. But is this superiority sufficiently great to warrant the waste of so much heat, and all of the other precious by-products which 340° I. Cc. WHITE—SHORTAGE OF COAL IN APPALACHIAN FIELD our European cousins find so much profit in manufacturing and selling tous? Are not our engineers equal to the task of manufacturing a first- class furnace coke without such an enormous waste of values? Are they less skillful than their German and English brothers? Why should we retain the steam-engine, to consume with frightful speed so much of our finest fuel, when much more power can be obtained by the use of the gas engine from an equal weight of impure or low grade coal? Fortunate would it be for our future if some master genius could arise in the great iron and steel industries who would at one stroke arrange to relegate both the steam-engine and the beehive coke oven to the junk heap of the wasteful past, like McCrea and his predecessor, the gifted Cassatt, have undertaken to do with the steam locomotive on one of the world’s greatest railways. Again, why should .the Pittsburg district permit these acres of coal barges, loaded with precious black diamonds, the heart of the finest coa! bed in the world, mined from its immediate hills, to float through its gates down to other marts at a minimum profit to any one owing to enor- mous losses by flood and collision, when it is absolutely certain that he- fore the century closes the coal from eastern Kentucky and southern West Virginia will be towed up the Ohio to replace what should never have been taken away. Would it not be prudent and the part of far- seeing business wisdom to let the Great Kanawha and Big Sandy coa! fields possess these southern markets, to which they are so much more cheaply accessible, rather than sell at a small profit today what will be bought back in the near tomorrow at triple or even quadruple the present selling price? The coal in the Appalachian field is the only large body of first-class coking fuel on the continent, and the first duty of those who control the bulk of the enormous iron and steel industries of this district is to conserve all that is possible of this precious fuel for that particular purpose. Another form of wasted energy not so apparent to the eye, but which in the aggregate probably amounts to much more annually than all other forms of energy, both consumed and wasted, is the waste of water, which the nation permits to pass unhindered to the sea, often destroying in a- year enough property in the Pittsburg district and between there and Cairo to pay the entire cost of control and utilization. With the waste and disappearance of our forests, these periodical floods are certain to increase in destructiveness. Why should this now worse than wasted power, all easily within the limits of electrical transmission, not be so stored, controlled, and utilized that we could not only have navigable rivers from Pittsburg to the Gulf the most of the year, upon which to distribute cheaply the products of the mills and factories, but could also thereby greatly prolong the life and growth of our famous industries? ne ‘a BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 344-356, PLS. 16-27 OCTOBER 11, 1909 AFTONIAN MAMMALIAN FAUNA? BY SAMUEL CALVIN (Presented by title before the Society December 31, 1908) CONTENTS Page Straticraphic position of the Aftonian deposits............. 0.2.0... cee 341 Relation of the gravels, in time, to the Aftonian interval................ 342 SEALING 6 o 5 ols Sctschl SRB SS Cops NIBP AN Neeele bee tia anne rt Zn ea cea ere 343 SE Mea EMOTES). acc0s) bac oo as 6 a cwiee 2s Weve ale le 6) eww wpurees Shwe eb ook 344 (LD ETS | DUEVGR ICI TES coi ke eA psec Laer gta eat ge nn 350 PMN PENG CANES ROSE ME TA on asrey ee aa el Iw hee ie! sure. oo'S: es Ayal oj ane’ AEG) oo es eret aS lala ee Bima dss Gad aes Soil LEP EVE TEMES! |» aye NAb a ag ores a on ete ae RR Nae ABD se reac SRR ane A Sil LADS aT MUDEr WUOTs. LACUGIYr, esas le. siete vote i etacs Goals wxeleh a a SAR Giantess 301 PCHMAS DIMMIOERAUS AMG. COLWMNOE. oo ons oe be eine once se essen es 351 Pacem: MMmInntt GCMETICONMUM. 2.20. ccc cb e cece esha eee ee esgues oo Sp CODOSCIOEAN: PENMAN: - 4); cei. fo ca ec ce wv od ae ae eed ew nee s 352 Bdentata ....... Mee Me pe Ber eee ase heer ae ere SS vehdbecais ate leis: Kuscors & OREO aes « 353 LEEDS SNP ig SCR RRORGERS FANE Set rae sl es fo Sr Ae eae ne ea gr a 353 TSU’ WET 5 Sage RA SUA gee Si eae eee ar re ae a 358 a Ae MM ORT AE ae oh oS aoajia sais GW ws a a Foose ate wile BFocd wih dg Siege gw ahd wa a’ 353 sae tat UR Gre PRE tS eho con Sn oe aha yp AS aca dere fS Rae we Hawke De ewe elas 354 STRATIGRAPHIC POSITION OF THE AFTONIAN DEPOSITS Between the two older drift sheets of Iowa, known respectively as the pre-Kansan and the Kansan, there are many evidences of a long interval of mild climate. Such an interval is indicated by intercalated weathered zones, soil bands, peat beds, buried forests, and aqueous deposits of sand and gravel. Chamberlin pointed out the interglacial position of the ex- tensive gravel beds at Afton Junction and Thayer and gave the name Aftonian? to the interval which they in part represent. The writer, dis- cussing the age of these gravels in the Proceedings of the Davenport Academy of Sciences, was led to conclude that they are the work of 1 Manuscript received by the Secretary of the Society December 31, 1908. 2See Journal of Geology, vol. iii, 1895, p. 272. When this editorial was written it was believed that the till beneath the gravels was the Kansan and that above them the Iowan. For later discussion and reference of the gravels to their true position be- neath the Kansan, see the same journal, vol. iv, p. 872. XXX—BULL. Groz. Soc. AM., Vou. 20, 1908 (341) 342 S. CALVIN—-AFTONIAN MAMMALIAN FAUNA streams which had their origin in the rapid melting of the pre-Kansan ice, and that they belong in reality to the closing phase of the pre-Kansan glaciation. In rapidly disappearing glaciers there was offered a reason- able explanation of vigorous, swollen streams such as might carry and deposit loads of gravel, and no efficient cause of such floods at any time between the beginning and the close of the Aftonian interval was so read- ily conceivable. Work on the gravel pits at Afton Junction and Thayer was stopped some years before the deposits came under the observation of geologists. If fossil bones were found during the progress of the excava- tion, there was no record of the fact. In view of the conclusion as to the conditions under which the gravels were laid down, contemporary faunas were regarded as impossible and no inquiries were made. Bones and teeth of post-Tertiary mammals have been found in the surficial deposits of Towa, but they have usually been referred in a broad way to the Pleisto- cene. The many known Aftonian peat beds have so far yielded no mam- malian remains, and very few mammals which could be referred definitely to any given stage of the Pleistocene have been heretofore discovered in the area between the two great rivers.* | RELATION OF THE GRAVELS, IN TIME, TO THE AFTONIAN INTERVAL Within the past few months, in Harrison, Monona, and other western counties of Iowa, Shimek has found stratified sands and gravels of great thickness and extent lying between the pre-Kansan and the Kansan drift.® The stratigraphic position is clear and well established; the gravels are Aftonian in age, but they contain evidence that they were not deposited until some time after the old pre-Kansan ice-sheet had completely disap- peared. In the light of this evidence, it may be necessary to revise the opinion concerning the precise date of deposition of the Thayer and Afton Junction beds, expressed in the Proceedings of the Davenport Academy of Sciences. The new evidence comes in the form of a fairly rich mam- malian fauna that must have been contemporary with the deposition of the gravels, but which certainly did not live in the wet, chill, verdureless region that coexisted with the melting of the pre-Kansan ice. As noted 3Samuel Calvin: The Aftonian gravels and their relation to the drift sheets in the region about Afton Junction and Thayer. Proceedings of the Davenport Academy of Sciences, vol. x, 1905, pp. 18-30, plates i—vii. 4Jn the third edition of The Great Ice Age, by James Geikie, 1895, p. 759, Professor Chamberlin refers to Hquus complicatus, Lepus sylvaticus, and Mephitis mephitica as occurring in interglacial deposits in Iowa, but the horizon is not definitely stated. Mure definite is Leverett’s reference to the occurrence of Lepus and Mephitis at the Yarmouth horizon, between the Kansan and the Illinoian drift sheets, near Yarmouth, Iowa. See Proceedings of the Iowa Academy of Sciences, vol. v, 1898, p. 82. 5B. Shimek: Aftonian sands and gravel in western Iowa. Science, new series, vol. xxviii, December 25, 1908, p. 923. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 16 FIGURE 1.—THE COX GRAVEL PIT AT MISSOURI VALLEY, IOWA Showing (A) Aftonian gravels overlain by (K) Kansan drift FIGURE 2.—THE PEYTON GRAVEL PIT NEAR PISGAH, IOWA Showing (A) and (K) in the same relations as in figure 1 THE COX AND PEYTON GRAVEL PITS ai has ‘[PMUBUS Of} JO SSOUYOTY} OY} PUL Yoo} JAMO], OY} JO SSoUyoIy} oY} VJON ‘oTduexsa a0Z “"d ‘q}003 ey} JO MOS JO OPIS Yore uo soovds uedo oY} JO WAOJ oY} AQ Po}BoOIPUT JORT BV ‘aingVAIND a10Ul PLY A[[VULSLIO Soldes ABMOT OAL, ‘OZIS [BIN}JVU VIB SOInSY oyL “eMOT ‘KJuUN0d STIL “drqsaMo} suodry ‘eg UOTjoeS UT YIIS UvIUOJJW WOT ‘KoTPH 172008 snnby ‘osaoy ULAPRTD oy} JO F090} AvpOWId-1BVjoM JaMO] pue azsddy) ASYOH NIMGV19S AHL SO HLSSL Li “1d ‘8061 ‘0% “10A . “WY “OOS “1049 *11Nd RELATION OF THE GRAVELS TO AFTONIAN INTERVALS Byte by Shimek in the article cited, the beds contain the shells of river mol- lusks belonging to species still living in Iowa; all the evidence shows that the climate was comparatively mild, and that the streams which carried and distributed the fluvial deposits, the streams which transported the mammalian remains and distributed the shells of the river mollusks, were not a product of melting pre-Kansan glaciers. ‘The mammals are repre- sented by bones and teeth in such numbers, in such a state of preservation, and are found at so many widely scattered exposures along different stream valleys as to make it certain that they are not mere chance inclu- sions washed out of preexisting drift or out of preglacial deposits. It is worthy of note that the mammals consist of large herbivores. There are horses of at least two different species, one species of camel, the great stag, Cervalces, two elephants, the common Pleistocene mastodon, and at least one large Edentate, Mylodon. There are bones and fragments of bones that have not been identified. The great quantity of well preserved material would imply that the uplands between the stream valleys were densely populated, for only a small proportion of the animals that lived and died in the region would be represented by skeletons coming within the reach of floods. 'T’o supply these great herbivores with food required an abundance of vegetation such as could not be developed until some time after the pre-IKansan ice and all its climatic effects had disappeared from southwestern Iowa. LOCALITIES The fossil remains under consideration have come almost exclusively from the western slope of Iowa, the Aftonian beds having been exposed in the process of valley-making by the streams draining into the Missouri river. It is now known that Aftonian deposits occur at intervals all the way from Sioux City to Hamburg, but the valleys which have thus far received the greatest attention are those of Maple, Little Sioux, Soldier, and Boyer rivers. Gravels have been worked on a commercial scale along the Boyer, and mammalian remains have been uncovered at Denison, Logan, and Missouri Valley. At the point last named the most impor- tant is the Cox pit, which, by reason of the greater amount of work done in it, has furnished the larger number of the specimens referred to in this paper (plate 16, figure 1). The Peyton gravel pit, located about a mile southwest of Pisgah, has been the most productive of the Aftonian exposures in the valley of the - Soldier river (plate 16, figure 2). In the bluff on the east side of the Little Sioux river, a few rods south of the Monona-Harrison county line, there is a fine exposure of Aftonian gravels which has been worked inter- mittently and chiefly for road materials. Nothing is known of the find- 344. S. CALVIN——-AFTONIAN MAMMALIAN FAUNA ing of fossil remains at this point, but the outcrop is of especial interest for the reason that the overlying Kansan and the underlying pre-Kansan drift sheets are both exposed in place, with the weathered and ferruginous Aftonian between them. At Pisgah and Missouri Valley the till below — the Aftonian beds is not in sight. Farther up the valley of the Little Sioux, at Turin, in Monona county, — some good fossil remains have been found, and there are pits near Cas- tanea and Mapleton, in the Maple valley, which have produced bones of Aftonian mammals. A very promising area, which has not yet been carefully investigated, embraces a number of sections in the southeast corner of Lyons township, Mills county, and the adjacent sections in the northeast part of Scott — township, Fremont county. The Aftonian gravels occur in natural ex- posures within this area at a number of points, and they have been pene- trated in farm wells which have gone down through the Kansan drift. There are trustworthy reports that mammalian bones have been taken from the gravels in some of the wells, and a number of finds have been made in the gravel pits, which are operated here on a relatively small scale. A complete set of left molars of a large horse, upper and lower, was found by Mr E. L. Gladwin while grading a road in section 35, Lyons township, Mills county, and is now in possession of the writer. A considerable portion of the skeleton was present, but the bones were too soft for preservation. Both upper and lower series of this fine set is illustrated in plate 17. The Gladwin horse was found in a fine blue clay, a bed of silt, that here in places overlies the gravels but is of the same age. Similar silts occur with the gravels, but interbedded with them, at — Missouri Valley and Pisgah, in Harrison county. | THE AFTONIAN HorRsEs In the collections under consideration horses are represented by a much larger number of bones and teeth than any of the other types of Aftonian mammals. There are bones from nearly all parts of the skele- ton, but leg bones and foot bones are most common and most significant. Among the teeth there are eighteen superior molars and premolars and about an equal number from the lower series. The Gladwin set is the only one that is complete; the other teeth show great variations in the amount of wear and in minor details, and it is quite certain that they represent a number of individuals. At least two species seem to be clearly indicated. In one the teeth are larger than those of the modern — species, as is shown by the following comparisons and measurements of — the upper molars of the Gladwin horse. Comparison is made with the — BULL. GEOL. SOC. AM. VOL. 20, 1908, PE. 18 SUPERIOR GRINDERS OF EQUUS SCOTTI! GIDLEY From the Cox pit, Missouri Valley. Figures 1, 3. Grinding surface and outer side of tooth number 116. Figures 2, 4. Same views of tooth number 117. Figures 5, 6. Grinding surfaces of teeth numbers 119 and 118. All figures natural size. THE AFTONIAN HORSES 345 measurements of the teeth of the domestic species, expressed in milli- meters, as given by Gidley in the table on page 98 of volume xiv of the Bulletin of the American Museum of Natural History. Only the trans- verse diameters are compared, but the other dimensions show correspond- ing differences in size. In the case of the teeth of the Gladwin horse, to quote from Gidley, “the transverse diameters were measured across from the exterior ridge of the mesostyle to the exterior wall of the posterior . lobe of the protocone, exclusive of cement.” In the Gladwin horse fully half the original length of the teeth has been worn away. The antero- posterior dimensions of the entire series of superior grinders, measured in a straight line from the sharp, anterior enamel fold of p* to the pos- terior, outer fold of m*, is 187 millimeters. The antero-posterior dimen- sions of the individual teeth, following the outer curve of the series, but inside the metastyle and parastyle, are: p?, 43.5 millimeters; p?, 33 milli- meters; p*, 31 millimeters; m*, 25 millimeters; m?, 26 millimeters, and m*, 32 millimeters. This gives a total length of the series around the outer curve, but inside the external styloid ridges, of 190.5 millimeters. Table showing comparative transverse Diameters of the Teeth of the Gladwin Horse. De. p’. De DO meal paddler Sa anke Gidley’s largest draft horse............. 28505) BO20) | 238-0.) 28.0) | 26.0 1 23.0 Meer fossil horse.............--00005 28.7 | 32.0 | 32.5 | 30.0 | 28.5 | 26.0 USS 2S SS eae eee mere ree On| On 220 2220") 320, Average of the 8 horses recorded in Gid- Li 0 § (ACA eee 24.8 | 26.1 | 26.9 | 26.0") 25.4 | 22.2 Differences when the Gladwin horse is compared with the average of Gid- MRED OMONSES occ. sve eas cms seen dees Oe ook roo) 4 On dah le 38 There are a number of teeth from the Cox pit at Missouri Valley, and one from Turin, which agree in dimensions with the larger teeth of the Gladwin horse, and are. evidently from the same species, if transverse diameters may be taken as a guide. These may be noted in tabular form as follows: Trans- | Antero- Reference to illustration. verse | posterior] Length. diameter. |diameter. Catalogue number. 116 late 16. fioores als oa: ack os ycise syst se aon ae) 95 7 Plate lS. Heures Sear aces ad Neds ase h 33.5 35.0 82 118 iace 1S) eure On y nes SRL e oe eee iene 32.0 32.0 38 119 latent - MOUe Oe sare ce este kh occas eee 5 a) 29.0 50 125 GNiovallustrated))ssies te oe ete sk 31.0 30.0 62 136 (KromeDurin; notillustrated 3.24.2... 33.0 30.0 80 346 S, CALVIN—-AFTONIAN MAMMALIAN FAUNA An imperfect second upper premolar, with the thin, anterior edge broken away and having a transverse diameter of 29 millimeters, belongs in this group of large teeth. Nearly one-third of the crown has been worn off by use; the part remaining measures 65 millimeters in length. Among the recognized species of Pleistocene horses the teeth of the Gladwin horse and the others above noted agree best in size with Hquus . scottt Gidley, from the Sheridan beds, Rock Creek, Brisco county, Texas,® though tooth number 117 is practically identical in size and other details with the superior third and fourth premolars referred by Gidley to Equus pacificus Leidy.* Comparing the Gladwin teeth with the measure- ments given for Hquus scott: in the American Museum Bulletin, volume xlv, page 136, the close agreement becomes apparent: PS pt Pp. ae m. °°. Antero-posterior diameter : Equus SCOUL = Sa. ce 5 eee eee 43.0 34 oo 30 dl 31 Gladwin: shorsé 5 24¢ <2 3s eee 43.5 33 31 25 26 32 Transverse diameter : EQUUS: SCOUl=..2 bab tees eee ee eee 00.5 33.0 33.0 30 29.0 24 ~~. dorlaGayan. RONSE 2c once hee ke ee 28.7 .32.0 32.5 30 28.5 26 The differences that appear in making these comparisons may be ac- counted for on the basis (1) of individual variations and (2) of differ- ences in the amount of wear which the teeth of the two animals has undergone. The measurements of Hquus scotti given on page 136 of the work cited are those of an individual “in which all the teeth have come into full use,” but presumably an animal comparatively young. ‘The teeth of the Gladwin horse, on the other hand, have been worn down to about half of their original length. The greatest discrepancy appears in the antero-posterior diameters of m+ and m? and in the transverse diam- eters of p? and m*. Applying Gidley’s “Laws governing the changes of diameters of the tooth crowns,” formulated on page 99 of the American Museum Bulletin already quoted, the differences are largely, if not wholly, explained. After the molar-premolar series comes into full use, according to law (1), the antero-posterior diameter of each of the inter- mediate teeth diminishes at first very rapidly, and then more gradually to the roots. Differences even as great as those seen In m* and m? are to be expected. The antero-posterior diameter of m? in the Gladwin horse accords with law (3). The differences in transverse diameters of the first and last teeth of the series exemplifies that part of law (4) which is expressed in the clause “p? gradually diminishes, while m* increases in 6 Bulletin of the American Museum of Natural History, vol. xiv, p. 134. TOD: (cits. apsaleae BULL. GEOL. SOC."AM. 3 VOL. 20, 1908, PL. 19 INFERIOR CHEEK TEETH OF FOSSIL HORSES From the Cox pit, Missouri Valley. Figures 1 and 3 and 2 and 4 illustrate two of the thin, nearly cementless lower teeth with thin, flexuous enamel, referred to Hquus complicatus Leidy. Figure 5 is a short, well-worn tooth of the same species. The two molars of figure 6 have the same characteristics as the lower teeth of the Gladwin horse, Equus scotti (plate 17, figure 2). Natural size. THE AFTONIAN HORSES Bas: transverse diameter as the crown wears away.” In the present case the teeth are the only parts available for study, but these are in such perfect accord with the teeth of Hquus scott. Gidley that there need be little hesi- tation in referring them to that species. Hquus scotti has been recog- nized with doubt in collections from the Sheridan beds near Hay Springs, Nebraska,® a point farther north than southwestern Iowa and equally as far from the type locality. The collection contains a few teeth of smaller size, agreeing in dimen- sions and in the enamel foldings with teeth which have been referred to Hquus complicatus Leidy. A superior third molar, number 128, from Missouri Valley, shows a very complicated pattern, even though consider- ably worn. Its dimensions are: transverse diameter, 24 millimeters ; | antero-posterior diameter, 27 millimeters; length, 60 millimeters. An Aftonian gravel pit at Turin, lowa, has furnished an imperfect superior molar, number 122, intermediate between the first and the last of the series, but its exact position undetermined, which shows a transverse diameter of 28 millimeters and a length of 70 millimeters. The anterior fourth of the tooth has been split off, but what remains shows very com- plicated enamel foldings. Another tooth, number 124 (plate 21, figure 3), of somewhat simpler pattern, but still sufficiently intricate to belong to H. complicatus, is from the Cox pit at Missouri Valley; it is 28 milli- meters in transverse diameter, 29 millimeters antero-posteriorly, and 70 millimeters in length. Tooth number 121 (plate 21, figure 4) is also from the Cox pit; it is 75 millimeters in length, but little worn; the enamel pattern is much simpler than in any of the other teeth so far noted. It agrees with Hquus excelsus and H. occidentalis in the absence “of the little enamel fold near the bottom of the deep valley between the protocone and the hypocone.” It is 28.5 millimeters in transverse diam- eter and 30 millimeters from front to back. In size and pattern, how- ever, this tooth is almost identical with Gidley’s figure 3 A, in the Ameri- can Museum Bulletin, volume xiv, page 97, and this figure is described as a molar of Hquus complicatus. If the teeth illustrated in figure 3, page 97, and in figure 7, page 109, of the bulletin above quoted may be referred to one species, then all the superior molars from the Aftonian gravels of southwestern Iowa may be arranged under two species distin- guished by differences in the size of the teeth, namely, Hquus scotti Gid- ley and Hquus complicatus Leidy. A specimen which can not with certainty be referred to the Aftonian gravels may be worthy of note. A few years ago there was received from Sw. D. Matthew : List of the Pleistocene fauna from Hay Springs, Nebraska. Bulletin of the American Museum of Natural History, vol. xvi, 1902, p. 317. 348 S, CALVIN—-AFTONIAN MAMMALIAN FAUNA Mr John H. Charles, of Sioux City, the fragment of a maxillary with five molar-premolar teeth in place, shown in plate 20. ‘The third molar is missing. The sender was not certain of the exact locality or the geological horizon from which the specimen came, but he added the information that similar teeth had been found in a sand pit along the Big Sioux river. The teeth referred to in this last statement are those mentioned by Bain in his report on the geology of Woodbury county,® and pronounced by Cope to be “three left superior molars of the horse, Hquus major Dek., of Pleistocene age.” ‘The sand pit which furnished the teeth submitted to Cope is now known to be a part of the same series of Aftonian deposits recently described from Monona and Harrison counties. The teeth illus- trated in plate 20 are, beyond much question, from the Aftonian horizon, though satisfactory proof is lacking; they are more completely worn out than any of the other teeth in the collections, having been cut away by use almost to the fangs. ‘The first molar has actually been ground through to the lower end of the enamel which surrounded the anterior lake. The transverse diameters are: p?, 24.5 millimeters; p*, 27 millime- ters; p*, 28 millimeters; m*, 26 millimeters; m?, 26 millimeters. Length of the series from the sharp anterior enamel fold of p? to the posterior edge of the metastyle of m*, 137 millimeters; the corresponding dimen- sion in the Gladwin horse, referred to Hquus scottt Gidley, 155 milli- meters. ‘The teeth of the Sioux City horse represent a stage of wear even more advanced than Gidley’s A*, figure 3, page 97, of the bulletin above quoted. Without hesitation they may be referred to the species Hquus complicatus Leidy, the great simplicity of the enamel pattern being ac- counted for on the basis of changes due to wear. © Of the lower molar-premolars there are two well marked types which probably correspond to the two species, Hquus scotti and Equus compli- catus. The left mandibular series of the Gladwin horse, shown in plate 17, figure 2, illustrates one of these types. ‘The teeth have very thick cementum and are unusually heavy; the transverse diameters measured in millimeters, exclusive of the cementum, are: p,, 18; pz, 19; p,, 21; m,, 17. The other molars are broken and can not be measured. The thick- ness of p,, including cementum, is 24 millimeters. The length of the series antero-posteriorly is 195 millimeters. Another notable feature of these teeth is the great thickness of the enamel. The same thick enamel and massive character are seen in the two inferior molars of figure 6, plate 19, the specimen illustrated being from the Cox pit at Missouri Valley. This specimen may without doubt be referred to the same spe- ®H. Foster Bain: Geology of Woodbury county. Iowa Geological Survey, vol. v, 1896, p. 277. Following Todd, Bain believed this sand was preglacial. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 20 MUCH WORN MOLARS AND PRE-MOLARS OF EQUUS COMPLICATUS LEIDY Sent from Sioux City, Iowa, but the horizon and locality are not definitely known. Natural size BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 21 FOSSILS OF EQUUS COMPLICATUS AND CAMEL Figure 2. Inferior molar of the thin, cementless type referred to Equus complicatus Leidy. Figures 3, 4. Teeth 124 and 121 referred to Equus complicatus Leidy. Figure 1. Proximal phalanx of camel, side view. All figures natural size THE AFTONIAN HORSES © 349 cies as the Gladwin horse. All the other inferior molars in the collec- tions belong to the other type. ‘The transverse diameters are less, the cementum very meager, and the enamel is much thinner and more flex- uous, as will be apparent on comparing figures 1 and 2, plate 19, with figure 6 of the same plate. ‘That these differences are not dependent on age and wear is indicated by the fact that lower molars equally as short as those of the Gladwin horse agree in essential features with 1 and 2, plate 19. Figure 5 of this plate is an example of a short, well worn, inferior molar of this type. ‘The thinner teeth, with thinner and more flexuous enamel, may be looked upon as teeth belonging to a species quite distinct from the Gladwin horse and may be associated with the superior molars which have been referred to Hquus complicatus. Figures 3 and 4, plate 19, are external faces of the thin, almost cement- less type of inferior molars, the grinding surfaces of which are shown in figures 1 and 2. The tooth, figure 3, shows the effects of alveolar ab- scesses from which the animal probably suffered seriously. Whether this disease hastened the death of the individual may not be known, but it is certain that life was cut short from some cause before the teeth were very much worn. There are many equine bones from the Aftonian beds of Harrison and Monona counties which, while more or less fragmentary, are in a fair state of preservation. There are two humeri, right and left, each lacking the proximal articulation. These indicate an animal about the size of the average modern horse, the radius and ulna of the domestic species fitting perfectly with the radial articulation of the fossil humerus. There are portions of the radius among the fossil bones, four tibie, four imper- fect metapodials, four first phalanges, and other portions of equine skele- tons. ‘The most perfect of the tibie is comparatively small. The animal to which it belonged was adult, but the size would indicate a rather small pony. On the other hand, the distal ends of two of the fossil tibiz are equally as large as the corresponding part of Hquus caballus, and the same is true of the distal end of a fossil radius. The sides of the broad- ened articular extremity of the Aftonian radius is abraded, making meas- urements impossible, but 70 millimeters above the articulation both modern and fossil bones are 60 millimeters in transverse diameter and 35 millimeters in thickness. The fossil metapodials are large and strong and differ in cross-section from the same bone of the domestic species, being more nearly circular in corresponding parts of the shaft. The splint bones were evidently more rudimentary than in the modern horse. Three of the first phalanges are as large as those of the present coach horse; the largest one measures 92 millimeters in length, is 58 milli- 350 S. CALVIN--AFTONIAN MAMMALIAN FAUNA meters in transverse diameter at the proximal end, 41 millimeters broad at the narrowest part of the shaft, and 51 millimeters at the distal end. A slenderer phalanx, that of an immature individual, is 87 millimeters long and the narrow shaft is 33 millimeters wide. An examination of the equine bones from the Aftonian gravels, entirely apart from the evi- dence furnished by the teeth, suggests the possibility of at least two Aftonian species, one somewhat smaller than the average horse of today, the other fully equaling the modern horse in size. The teeth of the Gladwin horse, teeth 116 and 117, shown on plate 18, figures 1 and 2, and the other teeth above referred to Yquus scotti Gidley are all notably larger than those of Hquus caballus, while the teeth re- ferred to Equus complicatus are about the size of the teeth of the domestic horse. According to Gidley, in the article from the American Museum Bulletin, volume xiv, frequently quoted in this paper, the head and the teeth of the Pleistocene horses were proportionately larger than in the modern species. On page 139 of the bulletin Hquus complicatus is de- scribed as “a species with teeth about the size of those of the ordinary draft horse and of moderately complex pattern, but with the bones of the skeleton about the size of those of the smaller varieties of the western pony.” Notwithstanding the large size of the teeth in Hquus scott, it is said that “this species represents a horse about the size of the largest western pony.” While in all probability the Aftonian horses represent but two species, Equus complicatus and Equus scotti, the fact should not be overlooked that some of the bones and teeth (figures 2 and 4, plate 18, for example) agree with those of Hquus pactficus, concerning which it is stated that “the skeleton indicates a horse about the size of the ordinary draft horse, but the skull is proportionately larger.” Many of the fossil bones are about the size of those of the ordinary draft horse. OTHER UNGULATES Of the ungulates associated with the Aftonian horses, one of the more significant is the camel. This is represented by a single first phalanx which came from the Peyton pit at Pisgah. The bone is shown of nat- ural size in plate 21, figure a and plate 22, figure }- It is 127 milli- meters long, 36 millimeters jn transverse diameter at the proximal end, 31 millimeters across at the distal end, and the smallest diameter of the shaft is 20 millimeters. Other Artiodactyls are indicated by the antler of a large stag from Denison, Iowa, related to Cervalces americanus, the — distal ends of two metapodials, one of which, lacking a part of the articu- lation, is shown full size in plate 22, figure 2; and there are two unidenti- _ /3 BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 22 FOSSILS OF RUMINANTS Figure 1. Astragalus of large ruminant; from Cox pit; natural size. Figure 3. Imperfect cannon bone of large ruminant; Cox pit; natural size. Figure 2. First phalanx of camel, front view; Peyton pit; natural size. “Uuax([ WO1Z ‘Govquownig” snwabvuns0d ozIS [BIN}vU J[VYy-ou0 {41d UOST spydaiq] JO AVIOW °G NSA ‘ozs [vanjzeu Jley-auo ‘41d SNINADINIYd SVHd314a GNV LNVNIWINY 4O SsTisso4 xO) WOdIj ‘0100 U0 poyizuoprug €2 “Id ‘8061 ‘02 “10A ‘LT ounsiy “WV “OOS “1035 “11Nd PROBOSCIDEANS 351 fied horn cores (plate 23, figure 1). There are two large calcanea and other undetermined bones, probably of Ungulata. PROBOSCIDEANS ELEPHANTS Elephas imperator—Three elephants are indicated by the collections from the Aftonian gravel pits. A large, shghtly worn molar, shown on plate 24 about three-sevenths natural size, has the massive proportions and the coarse ribs which distinguish Hlephas imperator Leidy. This ponderous, clumsy tooth is from the Peyton pit at Pisgah; it is 290 milli- meters (about 11%, inches) in length, 108 millimeters (414 inches) across the grinding surface, and 265 millimeters (1034 inches) high, measured between two planes parallel to the grinding surface. The enamel loops, corresponding to the longitudinal ridges on the lateral faces of the tooth, vary in thickness and in the width of the intervening spaces, but on the whole they are more constant in these respects than are those of the tooth illustrated by Holmes? and Lucas"? and which served to re- establish Hlephas imperator as a valid species. In some parts of the Iowa specimen the ridges are fully an inch in width, the number in 10 inches ranging from 11 to 14, according to the part of the tooth selected for measurement. Besides the large tooth from Pisgah, there is an im- perfect lower jaw from the Cox pit at Missouri Valley (plate 25, figure 1) which belongs to this species. In both rami the inner side of the alveolus has been broken away, but the outer wall is intact and shows the broad, vertical grooves corresponding to the wide ridges on the lateral face of the tooth. These are of the same order of magnitude as the ridges of the Pisgah tooth referred to Hlephas imperator. A large femur to be noted later probably belongs to this species. EHlephas primigenius and EH. columbi.—There are other and very differ- ent elephant teeth in the Pleistocene collections of the University of Iowa in which the number of ridges in 10 inches range from 20 to 25. The exact horizon for some of these is not known, but there is one from the Cox pit showing 20 folds or ridges in the space mentioned, and another from the gravels at Denison showing 25. The specific relationship of these admits of little doubt. Lucas, in the work cited, page 159, specifies 18 ridges in 10 inches as characteristic of Hlephas columbi and 24 in the same space as marking the molars of HL. primigenius. Making the neces- 10 William Henry Holmes: Flint implements and fossil remains from a sulphur spring at Afton, Indian Territory. Report of U. S. National Museum for 1901, p. 244, plate 9. uf. A. Lucas: Maryalnd Geological Survey, 1906. Pliocene and Pleistocene mam- — malia, p. 167, pl. xxxviii, fig. 2. 352 S. CALVIN—-AFTONIAN MAMMALIAN FAUNA sary allowance for individual variations, the Cox Pit tooth, with its aver- age of two folds. to the inch, is referred to H. columbi, and the Denison ~ tooth, with two and a half folds to the inch, represents, without doubt, the H. primigenius. The last agrees in almost every minute detail with a tooth of H. prumigenius from Europe. MASTODON: MAMMUT AMERICANUM The common American mastodon is represented in the Aftonian col- lections by a portion of the lower jaw—the symphysis and left ramus, with the last three molars in place (plate 25, figure 2)—and by three separate molars. ‘The jaw is from the Pisgah pit and the separate molars are from Missouri Valley. The Pisgah specimen is massive and shows the deep sockets for the mandibular tusks. The teeth from Missouri Valley are molars 4, 5, and 6, but they are not from the same individual. The fifth molar has the crown completely worn down, and the fangs show effects of absorption; the sixth molar is perfectly developed, but prac- tically unworn. OTHER PROBOSCIDEAN REMAINS The other proboscidean fossils worthy of note include fragments of two tusks from Denison, a complete left tibia (plate 25, figure 5) from Mis- souri Valley, a humerus and a femur (plate 25, figures 4, 6), both imper- fect, from Pisgah, and a cervical vertebra (figure 8) from Turin. A scapula, complete when taken from the pit at Missouri Valley, was allowed to crumble to pieces for lack of care by the finders. ‘There are two caudal vertebra, and a fragment of a pelvis, and, in addition, there is a section of a lower tusk of the mastodon. The large femur mentioned above is 45 inches long, and yet it lacks all of the enlarged proximal end; it is broken at the thin, flattened part of the shaft below the great trochanter. When complete the length was certainly more than 61 inches, the reported length of the femur of H. wm- perator from Keene, Oklahoma, noted by Lucas on page 168 of the work cited above. The Warren mastodon was among the largest of its species; its femur, complete, is said to be 45 inches in length? The Pisgah femur belonged to an animal larger than the ordinary mastodon, larger than the modern elephant or the northern mammoth, and it is a fair in- 12'The length of the femur of the Warren mastodon does not seem to be stated in Doctor Warren’s classic memoir, but on page 107 he compares the femur of the Cam- bridge mastodon with that of the elephant Pizarro. This bone in the Cambridge speci- men measures only 36 inches in length. In the Twenty-first Annual Report of the Re- gents of the University of the State of New York, pages 120 and 127, there are compara- tive measurements; the femur of the Warren mastodon is given as 45 inches long and that of the Cohoes mastodon as 41% inches. ‘yd uoj,sA0g ‘Apter woznuadw spyda)y JO AB]OW JO MIA VpPIS [e1njeU Sy}UeAVS-991q,L, 9ZIS YOLVYAdW! 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GF SeINSsveWM JUIWISBAJ Iq, ‘qessiq “Id uojyAOG WOAJ ANMJ JOOJIOdWMy “HY VINSTY ‘“AO[[VA TANOSSTI ‘VId xO) WOdIl BIC Je, JOOJIOT “G INST -19dU[ ‘fF WINS ‘qesstq “id uoJAOG WOIJ SNiswMINY 409z ‘U[LIAIOUN MWOZTAOY : BMOT ‘OSUDIBIA AVI S}J{SOdap [BIANT[V Wor ‘ToeUOd[B 2QwWNjI0D SNYydalA JO ‘SUOTLB[NOAV [VUTxoId Surly], ‘Mel AWMO'T ‘e ainsi “BMoyT ‘YVsstq 41d uojAV OY} WOIJ UOpoO}sVJ_ JO snueA jJoT *Z 9INSs “Wd XOD Worl ‘voZDUadum spyday JO MBE ABMO] JOOJIOdMY "T VANS STSAVYS NVINOLAV WOYS SANOd TISSO4 G2 “Id ‘8061 ‘0% “10A ) “WY “OOS “1049 *11Nd EDENTATA 353 _. ference from its great size that it belonged to the imperial mammoth, a tooth of which (plate 24) comes from the same gravel pit. EDENTATA MEGALONYX Some years ago Todd called attention to beds of sand and gravel below drift in southwestern Iowa. A paper on the subject was read before the American Association in 1889,* and the abstract states that “a large claw of some gigantic mammal was shown, which was obtained from Mills county, Iowa, in the sand below the drift.” A footnote referring to the specimen says that “this has been determined by Professor Leidy to be a claw of a Megalonyx.” The “sand below the drift” in Mills, as in all the other counties of western Iowa, is interglacial. It hes below the Kan- san drift, but there is another sheet of drift, the pre-Kansan, below it. On the basis of Leidy’s determination, however, the Megalonyx may be accepted as a part of the Aftonian mammalian fauna. MYLODON From the noted Cox pit at Missouri Valley there comes an imperfect terminal phalanx of Mylodon (plate 26). The tip of the ungual process is broken off ; otherwise it is practically complete and shows the character- istics of this part of Mylodon very clearly. The claw as a whole is pro- portionately much thicker, is less faleate, and tapers less rapidly toward the point than do the claws of Megalonyx. The ungual process is regu- larly rounded on the upper side instead of being compressed to a rela- tively sharp ridge. All the characteristics coincide with Owen’s classical description of the distal phalanges of Mylodon.** CORRELATION The Aftonian fauna is as yet very incomplete. Additions to the list of species must wait on the further development of the sand pits and gravel beds. Besides the sloths, the forms thus far discovered and recognized are all large herbivores. An attempt to correlate the Aftonian beds with Pleistocene faunal zones which have been established in regions lying out- 13 J. H. Todd: Evidence that lake Cheyenne continued till the Ice age. Proceedings of the American Association for the Advancement of Science, vol. xxxvii, 1889, pp. 202-293. 14 Richard Owen: Description of the skeleton of an extinct gigantic sloth. Mylodon robustus Owen, pp. 94, 95, 107, 122. Leidy’s work, A memoir on the extinct sloth tribe of North America. Smithsonian Contributions to Knowledge, accepted for publication December, 1853, p. 37, describes the ungual phalanges of Megalonyx. The plates in both of these publications assist in making clear the differences between the claws of the two great sloths mentioned. 354 S. CALVIN—-AFTONIAN MAMMALIAN FAUNA side the glaciated area would probably, at the present time, be somewhat premature, but there are a few facts of some significance which may be noted. The deposition of the pre-Kansan drift certainly did not take place until some time after the actual beginning of the Pleistocene, and yet Hlephas wmperator was present in the long, mild interval which fol- lowed the pre-Kansan. Associated with the imperial mammoth were such typical members of the Equus fauna as Hquus scott: and Hquus com- plicatus. The camel and the Mylodon add other faunal elements which have some bearing on the question of correlation. Fragmentary and in- complete as is our knowledge of the Aftonian fauna, enough is known to warrant the statement that it resembles most closely the fauna of the Equus zone or “Sheridan formation” as that fauna has been listed by Matthew?’ and Osborne.*® The localities from which the Aftonian fos- sils have been collected are not very far from the type localities of the Sheridan beds in Sheridan county, Nebraska. A statement by Scott, re- markable for its insight and suggestiveness, may here be quoted. Speak- ing of the Sheridan stage (Hquus beds), he says :™" “Tt is, to a large extent, of eolian origin and in places contains great nu™- bers of fossil bones. In South Dakota the Sherijan passes under a drift sheet, and probably it corresponds to one of the earlier interglacial stages.” If, as now seems probable, the Sheridan may be correlated with the Aftonian, it corresponds to the very earliest of the known interglacial stages. Though it follows an interval of rather rigorous and widely dis- tributed glacial conditions, the Aftonian must still be reckoned as part of the Lower, or earlier, Pleistocene; for it is very old when compared with the Yarmouth, the Sangamon, and the subsequent interglacial intervals. To the deposits of these later stages we must look for remains of the faunas of the Middle and Upper Pleistocene, if representatives of these faunas are ever found in the glaciated areas. POSTSCRIPT As an illustration of the fact that, owing to the rapid growth of geo- logical science, it is almost impossible to get a geological paper off the press before it is out of date, it may be said that since this paper was in the hands of the printer a considerable amount of new material has been 15 W. D. Matthew: List of the Pleistocene fauna from Hay Springs, Nebraska. Bulle- tin of the American Museum of Natural History, vol. xvi, p. 317. 16 Henry Fairfield Osborne: Cenozoic Mammal Horizons of Western North America. Bulletin no. 361, U. S. Geological Survey, p. 85. 17 William B. Scott: An Introduction to Geology, second edition, p. 782. New York, 1908. “AOTTVA LIMOSSTJL 3B JId XOD 94} WOAT eZIS [BIN}JeN NOGOTAW 4O Mv10 4O SM3IA YOINSANI GNV “IW¥aLv7 “YOIYadNs "WV °O0OS “1039 “11Nd 92 “Id ‘8061 ‘0Z “10A OZIS [BINJBU SIIXIS-9AY yNOGy BMOT ‘UOLHY AvOU [[OM B SulsSrp ur poywajoued joawas UBIUOIY Woy ‘AployT wnoyranu gruwoyr Jo rvjour yyStA Lojtodns 4s¥l ey} JO oovsins Surpursy AGIa1 WNOISIYIN LOWWYW JO YVIOW 1% “1d ‘8061 ‘02 “10A “WV “OOS ‘103459 *11NG POSTSCRIPT 355 received from the Aftonian gravels of southwestern Iowa. There are superior and inferior molars of Hquus complicatus and a fine claw of Megalonyx from gravel pits at Sioux City. From Missouri Valley there are a sixth molar of mastodon, a superior grinder of Hqwus scotti, and a second inferior molar of Camelus. A pit at Logan has furnished a fine molar of Hlephas columbi, while from Turin there has been received a large collection which includes a sixth molar of mastodon, three meta- tarsals and three first phalanges of Hquus, two phalanges of Camelus, a phalanx of either elephant or mastodon, and a great number of imperfect bones not yet identified. The probable presence of Megalonyx as a member of the Aftonian fauna is noted in the body of the paper; the only point concerning which there might be possible doubt is the age of the beds in which the specimen collected by Todd was found; the claw now in hand from Sioux City - places the matter of an Aftonian Megalonyx beyond question. We now have remains of Aftonian camels from three localities—Turin, Pisgah, and Missouri Valley. Two of the equine metatarsals and two of the phalanges from Turin are decidedly’ larger than the corresponding bones from the modern horse. One of these large cannon bones is complete and measures 30.5 centi- meters in length, while a metatarsal of a fair sized modern horse, with which it is compared, measures but 27 centimeters. Other measurements show corresponding differences between the fossil and the domestic spe- cies. One of the teeth noted in the paper (figures 2, 4, plate 18) agrees in size with Equus pacificus Leidy. It is larger than the teeth of Hquus scotts recorded by Gidley. It may be possible that this large tooth and these large cannon bones belong to a species larger than Hquus scotti; but on the other hand it is possible that individuals varied, and that some of the animals belonging to the species Hquus scottt may have exceeded “the size of the largest western pony.” ‘The solution of some of these questions must await additional evidence. | Probably the most important of the recent additions to our knowledge of the Aftonian mammals comes in the form of two molars of Mammut mirificum, or Mastodon mirificus Leidy. These teeth were found in Aftonian gravel which was penetrated in digging a farm well near Akron, in Plymouth county, Iowa. They are well worn down by use, and show the characteristic features of this remarkable species unusually well (plate 27). The teeth are the last of the upper molar series—one right, one left. With them were found portions of the tusks and a large number of pieces of the cavernous cranial bones. A part of the maxillary still adheres to the left molar. The left tooth measures 834 inches long and 314 inches 356 §. CALVIN—-AFTONIAN MAMMALIAN FAUNA wide across the second ridge. The right tooth is slightly smaller, 81% inches long, and the corresponding widths are also somewhat less. Leidy described the last lower molars of this species,1® and he found a somewhat similar disproportion between the right and the left. As in the teeth described by Leidy, the main body of the Akron molars is made up of six divisions or ridges. The sixth division, however, is somewhat irregular, and in the right molar is made up of more than two lobes. Be- hind the sixth ridge are elements of rudimentary ridges in the shape of a number of mammiform tubercles, not shown in the specimen illustrated by Leidy on plate xxv, figure 2, of the work cited. The wearmg down of the lobes of the transverse ridges exposes “large tracts of dentine bor- dered by thick festooned bands of enamel.” Our teeth are worn more than the lower teeth described by Leidy, and in the third division, as well as in the first and second, the dentinal tract is continuous. In the fourth and fifth ridges the tracts are still separated by the thick enamel. The beds on the Loup river, from which the original specimens of Mas- todon mirificus came, have been variously correlated with the Miocene, the middle and later Pliocene, and the early Pleistocene. Osborn in U.S. Geological Survey Bulletin 361, page 84, includes Mastodon muirificus in the fauna of the Hlephas imperator zone, but remarks later on the same page that “the exact position of the Hlephas imperator zone, also the question of whether it is of the same age as the Hquus zone, remain to be determined.” It is now certain that typical representatives of the Equus fauna are associated with Elephas imperator and Mastodon mirifi- cus in the Aftonian beds of western Iowa, and it is worthy of note that Mastodon americanus occurs abundantly in the same association. Signifi- cant among the new finds not heretofore recorded are a characteristic tooth of the imperial elephant and a tusk and sixth molar of the Ameri- can mastodon, which were taken from gravels under Kansan drift, in wells near Mapleton. Mastodon mirificus Leidy may be compared with Cope’s Dibelodon humboldtit Cuvier, referred to in the Fourth Annual Report of the Geo- logical Survey of Texas. Cope regards the horizon from which his speci- mens came as “more or less exactly equivalent to the Hquus beds.” 18 Leidy : The extinct mammalian fauna of Dakota and Nebraska, Philadelphia, 1869, p. 249, pl. xxv, figs. 1, 2. el ee i en BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA W/Olbe 20, PP. 357-368, PLS. 28-30 NOVEMBER 10, 1909 UNCONFORMITY IN THE SO-CALLED LARAMIE OF THE RATON COAL FIELD, NEW MEXICO?+ BY WILLIS T. LEE (Read before the Society December 29, 1908) CONTENTS. Page rope Statement Ol \ESUIUSY 2s ciijore 5 os a Bice wield oa dials we eels snes oo 6 2 80 357 iocanoneand condition of the rocks described.... 0.5.6.5. ecevccccecccs 358 Renata mI TAPIA LLIN Si a epee Ret io. - ayisionwe lots siniova 6.5, levels) sleaiapionale © lo « aveliata reeves id ene epe ations 359 eM i EIMCOM EON. o/s so veka cs ate se Goren och@tre | osc a@ine ale die since e's 361 DB ertmen RETA CUM re sac eae gece e. « syesatal AE oe ote cso) ital cadet Re Gia cme stave Le ele ele ene, ald srefels 363 SSL CMO IgM ETOSIOM He oe leven cal sare ous teteaaler aMeten cle ota lesemiateva je giecustelus elles aueier ate « eee O04 LP URCTE RBA EIONIRS 5 een a San eee Baye NEE ONOSPC Cn RA TON A Curt ct hn on Rt a a 365 Riagt forms from the Raton coal field, New Mexico... .....c..ccccccc sce 367 PRELIMINARY STATEMENT OF RESULTS The purpose of this paper is to describe an unconformity hitherto un- known that is of more than ordinary interest because it divides rocks, previously referred to the Laramie, into two distinct formations. The investigation is not complete, but enough is known to warrant the state- ment that during the time interval represented by the unconformity the sedimentary rocks previously laid down within the Raton field were sub- jected to erosion for a considerable length of time and the Rocky moun- tains west of this field were elevated and eroded to a depth of several thousand feet. The positions in the geologic column of the two coal-bearing formations are not yet fully determined. Until they are studied in detail and final correlations made, the positions here assigned and the names used should be regarded as serving only the temporary purpose of giving definiteness to the description. ‘The upper formation has the stratigraphic position of the Arapahoe of the Denver basin, but contains a flora apparently more closely related to that of the Denver formation than it is to the Laramie of the Denver basin. The lower one has the stratigraphic posi- 1 Published by permission of the Director of the U. S. Geological Survey. Manuscript received by the Secretary of the Society September 15, 1909. XXXI—BUuLL. Grou. Soc. AM., VoL. 20,1908 (G35) 300 «6W. T) LEE UNCONFORMITY IN THE SO-CALLED LARAMIE tion of the Laramie of the Denver hasin, but contains a flora that is ap- parently older than Laramie. ‘There are several possibilities of interpre- tation, as will be pointed out in the following pages, but the one consid- od ue \ c (From map of the General Land Office.) ered most probable is that the uplift and erosion represented by the un- conformity is contemporaneous with the post-Laramie uplift and erosion described by Cross? and others from the Denver region. LOCATION AND CONDITION OF THE ROCKS DESCRIBED The area described is in northern New Mexico east of the Rocky moun- tains and constitutes the southern part of the Raton mesa region, the 2, Whitman Cross: Geology of the Denver basin in Colorado. U. S. Geological Survey Monograph no. 27, 1896. LOCATION AND CONDITION OF THE ROCKS DESCRIBED 359 northern, or Colorado, part of which is well known through the writings of Hills. The Raton field extends from the Colorado line southward beyond the Cimarron river, a distance of about 40 miles, and from the base of the Rocky mountains eastward about 50 miles. Near Raton the rocks outcrop in the steep slopes of the lava-capped mesas that are fre- quently, though erroneously, called the Raton mountains. To the south and west of Raton the rocks have been deeply eroded and good exposures are numerous; also in the western part of the field the rocks are well exposed where they are upturned in Vermejo park and along the base of the Rocky mountains for a distance of about 5 miles south of the Colorado line. Farther south the outcrop is obscured by slide rock and the rela- tions complicated by intrusions of igneous rock. From Ute park east- ward in the Cimarron canyon and northward along the southeastern margin of the coal field many well exposed sections of the rocks were measured. Illustrations of these exposures are given in plate 30. Rock FoRMATIONS Although little can be said of the older rock formations of the Raton region, some knowledge of their general character and thickness is neces- sary In order to appreciate certain facts relating to the unconformity here described. The oldest formations of the region consist of the ancient crystalline and metamorphic rocks, probably of pre-Cambrian age. These are over- lain in some places by sediments of Pennsylvanian age and in other places by the red beds of the eastern Rocky mountains that probably range from late Pennsylvanian to Triassic. The red beds are here coarsely conglom- eratic, containing boulders of crystalline and metamorphic rocks derived from the older complex, and are so faulted and otherwise disturbed that it is difficult to measure their thickness, but 10,000 feet is believed to be a conservative estimate. The red beds are overlain by about 300 feet of Morrison shale and 200 or more feet of Dakota sandstone. Above the Dakota is a thickness of 3,000 feet or more of marine Cretaceous shale, the upper part of which is referred on paleontologic evidence to the Pierre. This shale grades up- ward through a transition zone of sandy shale, which Hills calls lower Trinidad,* to the massive Trinidad sandstone, which varies from 50 to 120 feet in thickness and which contains a marine fauna allied to that of the Pierre shale, but which in some places contains also thin beds of coal and 3R. C. Hills: U. S. Geological Survey, Elmoro folio, no. 58, 1899; also U. S. Geologi- cal Survey, Spanish Peaks folio, no. 71, 1901. 4R. C. Hills: U. S. Geological Survey, Elmoro folio, no. 58, 1899. 360 w.T. LEE—UNCONFORMITY IN THE SO-CALLED LARAMIE plant remains similar to those in the overlying coal measures. The coal- bearing rocks above the Trinidad sandstone are those that heretofore have been called Laramie, but that are now known to constitute two forma- tions. Since final correlations have not been made, it seems inadvisable to use definite names for these formations; but, as shown later in this paper, there are reasons for believing that the lower one may prove to be older than Laramie and the upper one younger than Laramie. Yor this reason the coal-bearing rocks above the unconformity will be provisionally referred to as the post-Laramie coal measures and those below it as the Cretaceous (Laramie or older) coal measures. Rock Formations in the Raton Field. Sandstone, conglomeratic, lithologically similar to the Poison Canyon beds, and provisionally cor- related with the Denver formation. * Post-Laramie (?) Sandstone below, conglomeratic at the base; coal- 1,200 teet. bearing shale above. : Unconformity. Sri | ees ee ee ee fe) 2 * Laramie or older (?) : . E 0—475 feet. Shale and sandstone, coal-bearing. | o S are ae Trinidad, . 50-120 feet. Sandstone, shaly at base. Pierre, Niobrara, and ‘ Benton, 3,000-+ feet. Shale. Dakota, 200 + feet. Sandstone. os Morrison, 300 +-feet. | Shale and sandstone. Red sandstone, coarsely conglomeratic, containing 3 Red beds, 10,000 + feet. boulders of the underlying crystalline and meta- 5 morphic rocks. 3 $s | Pennsylvanian (?) Sandstone, shale, and limestone, ob Ea = Archean. Ancient igneous and metamorphic TOCKR. The Cretaceous coal measures consist of shales and sandstones having a maximum measured thickness in Vermejo park of 475 feet, and lie appar- ently with perfect conformity on the Trinidad sandstone. . They thin rap- * Formerly called Laramie. ROCK FORMATIONS 361 idly eastward, their maximum thickness in the eastern part of the field being only 114 feet, while in some places not only were they completely eroded away, but the underlying Trinidad sandstone also was deeply eroded. The post-Laramie formation has a maximum measured thick- ness of 1,200 feet. The lower half consists principally of sandstone that is commonly conglomeratic at the base. The upper half has a greater proportion of shale, but in some places near the top there are thick beds of conglomerate, apparently belonging to a younger formation, the Poison canyon, but not separated from the underlying beds by any sharp line of demarkation. | EVIDENCE OF UNCONFORMITY In order to appreciate the significance of some of the facts relating to the unconformity here described, it is necessary to consider certain con- ditions existing previous to the uplift and erosion that produced it. (a) The absence of arenaceous material from the marine Cretaceous shale in the Raton field warrants the inference that the land areas which furnished the sediments either were located at great distances from this field or were so nearly baseleveled that the streams draining them could transport only clay and fine silt, and apparently proves fallacious any postulate that would account for the conglomerate at the base of the post- Laramie formation without renewed uplift in the mountain region from which the conglomerate was derived and the removal from the uplifted portions of considerable thicknesses of sediment. (b) The change in the character of the sediments from the fine text- ured shale of the Pierre to the coarse sand of the Trinidad sandstone may be due to uplift in neighboring areas, but this postulate is not necessary to account for the presence of the sand, for this sandstone represents the last stage of the vanishing Cretaceous sea and the sand may have been transported along shore from great distances. (c) The Cretaceous coal measures lie conformably on the Trinidad sandstone and were probably accumulated on broad, low-lying flats that were subject to slight oscillations. There are no fragments in them larger than grains of sand and the bedding is comparatively regular, differing notably in this respect from the post-Laramie beds, which are lenticular in many places. Few organic remains were found that would indicate the conditions under which the sediments were laid down. In one local- ity the supposed seaweed, Halymenites major, was found in rocks above the lowest coal bed, but fossil leaves indicative of fresh-water conditions were found in several other places. Judging from the regularity in the bedding of the sediments, no great difference in the original thickness of 362 WwW. T. LEE—UNCONFORMITY IN THE SO-CALLED LARAMIE the Cretaceous coal measures would be expected, yet the observed differ- ence is 475 feet, the entire formation disappearing within a distance of 15 miles from the point of its maximum thickness. The contact between the Cretaceous coal measures and the conglom- erate at the base of the post-Laramie is traceable in the face of the cliffs as an unmistakable line of unconformity by erosion. Near the Van Houten mine the conglomerate rests on 13 feet of coal and in a number of places within the mine conglomeratic material fills irregular cavities in the coal bed. Apparently these masses are due to the filling from above of fissures and irregular openings formed at about the time the conglom- erate was deposited. A quarter of a mile south of Van Houten this coal bed and 40 feet of underlying sandstone and shale are absent and the conglomerate rests on the Trinidad sandstone; also differences in the de- gree of dip between the Cretaceous and the post-Laramie coal measures were noted in a few places where for short distances the conglomerate extends across the eroded edges of the older beds, as shown in figure A, plate 28. The following is a description of the sections represented on plate 28: A is a section of Cottonwood canyon near Red River peak. The bedding planes of the lower formation dip 3 degrees; those of the upper are horizontal. B is a series of columnar sections extending from the base of the Rocky moun- tains eastward to Van Houten. (1) Section in hogback 5 miles south of the Colorado-New Mexico boundary. (2) Section near the southeastern extremity of Vermejo park. (3) Section in Vermejo canyon east of Vermejo park. (4 and 5) Sections at eastern margin of field south of Van Houten. C represents a series of columnar sections from near Carresso creek (6) north- ward along the eastern margin of the field. (6) Cliff south of Carresso creek. (7) Dawson, west side of Vermejo canyon. (8) Four miles east of Dawson. (9) Half mile north of Koehler. (10) Three miles east of Koehler. (11) Two miles southeast of Van Houten. (12) Van Houten mine. (18) North fork of Willow creek, 1144 miles north of Van Houten. (14) Two and a half miles west of Red River peak. (15) Red River peak. (16) One mile north of Red River peak. (17) North wall of Red River canyon. (18) Half mile south of Gardner. (19) One mile south of Raton. (20) Mesa north of Raton. (21) One and a half miles northeast of Raton. (22) Southeastern point of Bartlett mesa, 4 miles east of Raton. BULL. GEOL, SOC. AM. LEGEND CONGLOMERATE SANDSTONE SHALE . : : : ae ee T SECTIONS OF COAL FORMATIONS OF THE RATON FIELD, NEW MEXICO Showing character and relations of the unconformity separating the coal formations VOEm 20 niO0S Peas BULL. GEOL. SOC. AM. VOLE 20 1908 rE2o LARAMIE OR OLDE x HOGBACK IN VERMEJO CANYON, NEW MEXICO Formed by basal conglomerate of the post-Laramie coal measures EVIDENCES OF THE UNCONFORMITY 368 Sections were measured at short intervals in the escarpment along the eastern margin of the field, and these have been plotted to scale in figure C, plate 28, in order to show the irregularities in the line of unconformity. In figure B of the same plate measured sections are arranged in order from west to east, showing the thinning of the Cretaceous coal measures away from the mountains. The difference in thickness may be due in some measure to original deposition, but more probably is due to the par- tial removal by erosion of the Cretaceous beds. These facts apparently force the conclusion that no highlands existed near the Raton field which could by any known process, except that of invigorated erosion due to mountain uplift, furnish the pebbles found in the conglomerate at the base of the post-Laramie formation. There can be no reasonable doubt that erosion preceded the formation of the conglomerate, and the thinning of the Cretaceous coal measures from west eastward is best explained as due to this erosion. However, the most convincing proof of the duration of the erosion interval is found in the composition of the conglomerate. CoNGLOMERATE The base of the post-Laramie formation in nearly all parts of the Raton field is conglomeratic. In the western part, where the formations are upturned along the base of the mountains, and in Vermejo park, the con- glomerate is coarse, massive, and resistant and forms a prominent hog- back (see plate 29). It is coarsest at the base, where through a thickness of 100 feet the pebbles attain a maximum diameter of five inches. Above this massive basal part there is a small amount of carbonaceous shale with thin seams of coal, but for 600 feet above the unconformity the sediments are principally coarse grained sandstones locally conglomeratic. Eastward, or away from the mountains, the basal portion of the con- glomerate thins and the pebbles are smaller. In the eastern part of the field the conglomerate is well developed as far north as Red river. Near Raton it is doubtfully represented by a quartzose sandstone, but still farther toward the east the conglomeratic character reappears, as is shown graphically in figure B, plate 28; also the upper part of the conglomerate, as represented in the foothills at the eastern edge of the field, becomes finer textured toward the east, loses its conglomeratic character, and ap- parently is represented in the eastern part of the field by the cliff-making sandstones that occur in the lower 400 feet of the formation east of Raton. In the conglomerate were found pebbles of coal; sandstone similar to the Trinidad ; quartzose sandstone similar to the Dakota; pebbles of con- glomerate similar to the conglomerates of the Dakota; well rounded peb- 364 w.T. LEE—UNCONFORMITY IN THE SO-CALLED LARAMIE bles of petrified wood that may have been derived either from the Dakota or from the Cretaceous coal measures ; red sandstone that could have come only from the red beds; cherty limestone with impressions of crinoid stems; a variety of cherts; quartz; quartzite; jasper; igneous rocks, some of which are coarsely crystalline, others fine-textured, such as are found in the dikes of the mountain region; and fragments of feldspar, most of them completely kaolinized, but some of them retaining their original form perfectly enough to show cleavage faces. ‘The significance of these pebbles in showing the amount of erosion is made evident by reference to the thicknesses of the underlying strata shown in the generalized section previously given. MEASURE OF EROSION -. An estimate of the amount of uplift and erosion represented by the un- conformity involves the difficult problem of the distribution of land and sea and the altitude of the Rocky Mountain region during Cretaceous time. The assumption that a land-mass of crystalline rocks persisted in the mountain region throughout the Cretaceous period might satisfac- torily account for the conglomerate without renewed uplift, were it not for the thick underlying bed of fine textured Cretaceous shale; but it is difficult to understand how a coarse conglomerate could be derived from a land-mass that had furnished no coarse material during the accumula- tion of marine shale more than 3,000 feet thick, until that land was re- elevated. If it be conceded that the Rocky Mountain region of New Mex- ico was lowlying or submerged during the greater part of the Cretaceous period, and that uplift and renewed erosion preceded the deposition of the post-Laramie conglomerate, it remains to inquire what thickness of sediment was removed in order to expose to erosion the rocks represented by the various pebbles. Again, it must be confessed that further investigation is necessary before definite figures can be given, for it is not known how far the for- mations now upturned in the foothills region originally extended west- ward over the present mountain area, nor have the thicknesses of the older sedimentary rocks in the Raton field been measured. The Cre- taceous shale near Raton is known from well borings to be something more than 3,000 feet thick, and it is apparently much thicker than this near the mountains. The Dakota sandstone is about 200 feet and the Morrison shale at least 300 feet thick. The Red beds are faulted and otherwise greatly disturbed in this region, and their thickness can only be estimated at this time, but it is probably not less than 10,000 feet. BULL. GEOL. SOC. AM. VOL. 20, 1968, PL. 30 FIGURE 1.—CLIFF SOUTH OF CARRESSO CREEK, WHERE SECTION 6, PLATE 28, WAS MEASURED The formations given in order from base upward are Pierre shale, Trinidad sandstone, Cretaceous coal measures, and post-Laramie conglomerate FIGURE 2.—CLIFF ONE MILE NorTH OF RED RiveR PEAK, WHERE SECTION 16, PLATE 28, WAS MEASURED The post-Laramie conglomerate forming the top of the cliff rests unconformably on Trinidad sandstone CLIFF NEAR CARRESSO CREEK AND CLIFF NORTH OF RED RIVER PEAK, NEW MEXICO MEASURE OF EROSION 30! Assuming that the formations once continued westward with undi- minished thickness over the region now occupied by the southern end of the Rocky mountains, there must have been differential uplift and the removal of at least 3,600 feet of sediment before the pebbles of Dakota sandstone were obtainable, and erosion of at least 4,100 feet before the red sandstone was reached. The pebbles of igneous and metamorphic rocks that constitute the principal part of the post-Laramie conglomerate may have come from the coarser portions of the Red beds. There were boulders enough in the Red beds to have supplied the pebbles of the post- Laramie conglomerate, but the granitic material in the Red beds is re-: garded as quantitatively inadequate to furnish the feldspar which forms a considerable part of this conglomerate. It is probable that the granite rocks underlying the Red beds were exposed to erosion and furnished the feldspars, in which case the differential uplift and subsequent erosion could have been scarcely less than 15,000 feet. This estimate will proba- bly be modified after further investigation, but the statement is amply ‘justified that the unconformity in the Raton field represents erosion com- parable to the post-Laramie erosion of the Denver region, which Cross?° places at 14,000 feet. CORRELATIONS In some places in the Raton field the Trinidad sandstone contains marine invertebrates which, according to T. W. Stanton, who has identi- fied them, are of Montana age, belonging to the same fauna as that of the | underlying Pierre shale. In other places it contains thin beds of coal and fossil leaves similar to those in the overlying coal-bearing rocks. Undoubtedly the Pierre shale, the Trinidad sandstone, and the coal beds below the unconformity represent practically continuous deposition. The stratigraphic succession is essentially the same as.that in the Denver region, where the Laramie is the last of the conformable Cretaceous series and the marine beds contain invertebrates by which they are correlated with beds of similar position in the Denver section. However, the rocks of the Raton field that have the stratigraphic position of the Denver Laramie have yielded 15 species of plants, named in the accompanying table, which, according to F. H. Knowlton, who has identified them, are apparently older than Laramie. The species common to the Denver Laramie, as shown in the table, are those known to have a long time range 5’ Whitman Cross: Age of the Arapahoe and Denver formations. U. 8S. Geological Sur- vey Monograph no. 27, 1896, p. 207. XXXII—BuLuL. Grou. Soc. Am., Vou. 20, 1908 366 Ww. T. LEE—UNCONFORMITY IN THE SO-CALLED LARAMIE and are therefore of little use for correlation. The flora is not a large one and is not adequate for final correlation of the beds. ' The rocks above the unconformity have yielded a flora larger than that of the rocks below. From collections made by the writer in 1908, Knowl- ton identified the 29 forms listed in the following table. Of these 29 forms, 13 are positively identified species. Nine of the 13 occur in the post-Laramie of the Denver basin and only 2 in the Denver Laramie. Commenting on the age of this flora, Knowlton states that it is appar- ently post-Laramie and more closely related to the Denver than to the Arapahoe flora, which perhaps is to be accounted for by the fact that the known Arapahoe flora is very small as compared with the known Denver flora. This opinion is strengthened by the known range of the species previously found in the Raton Mesa region. The existence of the two coal-bearing formations has not been recognized heretofore, but judg- ing from descriptions of localities from which the collections came, most if not all of the 62 species of plants formerly collected in this region, mainly by the geologists and paleontologists of the Hayden Survey, came from the post-Laramie beds. Knowlton states that 20 of the 62 species are found only in the Raton Mesa region and can not be used for correla- tion, but that 42 of them are found elsewhere. Of these 42 species 24 have been found in the post-Laramie formations (Arapahoe and Denver) of the Denver basin, but only 3 are known from the Denver Laramie, and these 3 range downward into the Montana. In the absence of data sufficient for the definite corrolatiam of Te beds described, a choice of interpretation is left open in explanation of. the observed stratigraphic relations. In case all of the coal-bearing rocks of the Raton field are referred to the Laramie, as they have been up to the present time, we are confronted with the fact that the “Laramie” in this field contains an unconformity of considerable magnitude. By ac- cepted definition the name Laramie is “restricted to the rocks conferm- ably overlying the uppermost marine Cretaceous (Lewis shale where present) . . . the upper limit to be the first marked unconformity or its stratigraphic equivalent.” It is evident either. that the definition is not applicable in the Raton field or that the coal-bearing rocks. are not all of Laramie age. By definition the coal-bearing rocks in this field below the unconformity might be either Mesaverde or Laramie, but the rocks above the unconformity must be post-Laramie. . If the lower forma- tion be referred to the Laramie, the stratigraphic relations in the Raton field are apparently identical with.those in the Denver basin, the uncon- formity corresponding in time, as it does in magnitude, with the post- PLANT FORMS 367 Laramie unconformity, and the upper coal-bearing rocks with the post- Laramie formations of this basin. When the evidence of the fossil plants is thoroughly weighed this assignment, so satisfactory to the stratigra- pher, may require modification. PLANT FORMS FROM THE RAaTON CoAL FreLtp, New MExIco’ (Identified by F. H. Knowlton) Anemia perplexa (Hollick)... AGING, SOs ee ee ee Aspidium (?) CR/TUGS SU ee eee CISSUISESIORG os. 0. - Ficus lanceolata Heer........ Ficus speciosissima (?) Ward.. Ficus spectabilis (?) Lesq..... Hicusmmim@enms KN, ....-.... LAGS: S10 Soc: ees Flabellaria eocenica Lesq..... Geonomites wngeri Lesq....... Juglans sp. (?) LCUPUE SD Coe Magnolia hilgardiana Lesq.... Magnolia lesleyana Lesq...... Magnolia tenwinervis Lesq.. . LOOM LO re INGMTMDONS PSP. 2. che we ce ee Palmocarpon commune Lesq. - Platanus aceroidos Gopp...... Platanus guillelme Gopp..... Platanus haydenti Newb...... Platanus raynoldsii Newb..... Platanus rhomboidea (?) Lesq. JEATUCHTUS SS Oa een ee ene Quercus haidengeri or n. sp.... CLUE OUTS) COC ae ane ee Rhammus salicifolius (?) Salix (?) SOU G US ACs )iISDeice sos eas ks Sequoia brevifolia (?) se Vatesvolnuke (2) Teer... 0. 2... Viburnum montanum (?) Kn. . Cretaceous (below uncon- formity). eceoceeer eee oe eee ee ee ew we ew oe see ee eee ee oo Ce OO ONC caer ese ee ee eo ow eee eee eee ewe ose ee ee we ww 8 a) (0a) 6) (e (e) e) © 6.8) 6) 6 Found in Lar- amie forma- tion of Denver basin. eee ee ese oo © eee ee eo ee ses ceo ee es eo ew 8 ces ee ee we wo woe essere ees Cr ey oeoeeeere ere eee eeeceeseseee es oe eee eo ees ee eee eee ee eo wo see eee eee oe ee ee errr trees se ee eee eee ewe - co oO O OO OOo Ogio, Duc i Oc Os Coo Oo wo. Of Ono oO ee eee tee eee Oc COGOD OOG 6 oe ee eee re eee Post-Laramie (above uncon- formity). Found in Posrt- Laramie for- mations of Denver basin. xXKXKXKKKKKKKKKKKKKKKKKKKKK KKK ee ee ee ee ow ew ow eee eeee se ee eo a) ie; oe) el \ (6) 'e! ee) ee ee ete eee ee we wo eC eee ee ee ee eee cee eee eee eo eo eee ecereeeeeee eee ee ee ee eee oc er eos eee eee AO OOO OD OG OPO SIO OIG GOGO OFO COC 0 0 CeCe ORO Ce 3) le ¢) ©) e) »@) @ 0 0 6; ¢ ON Or ONO E OOM res @),0) 6)/e) 6)! s) (872) a) oe) 21)» © 16) lel \e, (») ° (6 8) @) 9) 1°) |) 8) 0) 8 « ss ee « 0 « « fa] Je) 00 e).0) (6) @) 14) 0) e) @ (0) |e) = \6) ©) © 0. 6) \8).6) © 0) «| a 0) 6 © 6 © © 6 0 6 © 2 ee eee ese ee es lee ee ee & © SSH Ole ee ee ee see eo These determinations were made more than a year ago, Since which time Doctor Knowl- ton has visited portions of the Raton Mesa and Canon City coal fields and collected ad- ditional material, which seems to indicate that the horizons here referred to post-Laramie may be of Laramie age. lections, he desires to hold the matter of final settlement in abeyance. Pending the full study of this, together with all previous col- 368 w.T. LEE—UNCONFORMITY IN THE SO-CALLED LARAMIE Summary of Plant Forms named in the preceding Table. Cretaceous (Laramie or | Post-Laramie. older). Number of forms collected in the Raton field in 1908.... 15 | 29 Numbenotgdoubtiulispeciess, secre nee cme eee eee 4 6 Number of positively identified species........... ..... 3 13 Number of positively identified species found also in the Post-Laramie formations of the Denver Basin........ 2 9 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 369-398, PLS. 31-32 DECEMBER 21, 1909 PROPOSED CLASSIFICATION OF CRYSTALS BASED ON THE RECOGNITION OF SEVEN FUNDAMENTAL DCE SOR Siva DRY (Read before the Society December 31, 1908) BY CHARLES K. SWARTZ CONTENTS Page PR ater AT ANON ane eh clin a Bis ca to as ei evra. t)) Sc Suet ous pebelacm © srieusisiisy eifeiie Glielerlevar metic! Spe™aher bile ale rere in ate 370 Panigieseroposed classification Of erystalse. 05 620s aac sa wn wje oe ere oe o's 371 PECMMMNMATY ‘CONSIGErATIONS (05 es. . wie od eee ke lee Seti hele Al AU a RON LB 371 J SLANT ELOUNE) Cie ae canek dared HU Ae ne RC NeTIO ne teks I Sa GPPSR ts al La eae Po IR a ee 371 MUM OEEING Apt c isu care Settee areata ae ay RP as FAY ETNA wie levvahe euaet ate ts 372 WEMEIOMMET Ol CSS MC AUTOM: Avevsiis, sive ol a chee allele eiauaves sd, w tae exovsiele alate elie lols 373 Ea SCO te AS Stel Galt] Olde ie ci ant ber ane gn evn ate chiswe ie ene lever ane oe Giepelaer o asd seus ote Me SerOe SV MNIMCLE Ves Nara. stone tears sie nese se aisle Galevsiclv we Sole ems <6. 5 ane 374 Mevelopment of groups and classes of erystals.. 52... 22205... «0% 374 Summary of development.........:...- Ape Wh Matera hes tN alk ny Rae 377 Reference of the classes to the accepted systems of ecrystals.......... 377 WMALACTCEISLICS OF the \SEVEN» CLASSES. sic c ee dais Wee sa eieyeislers se 6 ose o's 378 eT ROUVASTONS OL CEVSUAIS: oc a. gata aleiswhew wiee aie #4 diss ceva ie eee cclede awe we 380 MMieesriby oO: the seven classes Of crystals. ... 0.26. he coe cece cee eve 380 PME MEE OC VCLOPIMEMG 6. [ e.e ais nce cpetecd cl ateceie Sele «id abs letpla- oye) sieve lwilel eile le ellie 381 VAMP SIESIOD ESI 5015 Guth Cuts ck Ae LOPS eo SP OR AP ges eee ei eS On LP a ne 383 ReIhiVverranix: Ol CLASSES: ANG Sy StOMS. cia toc. ses odiere cg mie ed eicleiaie ets 383 Belative rank of the SyStemS. 6c. i..1..06...s.09-s5 5. ae irae 383 Relations of the rhombohedral and scalenohedral groups......... 384 IESTMCEROLMS VTEC bINV.. eee kia soe tio aetna one oi ake aa eters eo eyeloaua alare Ging ars 384 MOMMIES Of MME wENGUIMOC: jo\5'. cis cle sree ecw & © olla Siaio Miso sesh d atial aleve is Susie mia e's 385 Fa Miele EN SLORICAIN TEVA Weis) « cid a's eve e © blaiele © eS Sisreieuein'e Ge epela wbial e jere ole rallsnelal a, oye 385 Review of the development of the thirty-two groups of crystals....... 385 NVOGK. OF spreVlOUS INMVEStIEATONS so). 66 eps wclars scl @ miele 008 © ote) wp olene cos 385 EVES Sle a ee een eons, custo yrnrs Ciba iarradele atl ater vacicienel Sahay aes atePuns ian’ eileice lcatte'"s 386 ENE UPA pat cere enrte hate voneees Sutera OLE fe cial ade. Giana tor ate, ayone oh eit wishes ein se (OOS VHS Oe secrete ter taitcy eokeh accede, ees etrrer eta ec cettene tel rehiatrate amanetn Ash uae 389 Gain aa ea ed eee Ae ancien rich nile eines seem eine nee Stig ste eat! “OOO (CAPONE! SPST At One aie ai MMP ay Sees: 9 Ree RM Ae ee 391 MOTO Nai ary cy recut ee tenars chaste match tin ee cacy aneee oN AER aires a 18 a aves aise ODE Minnigerode een ee eee eee eee ce eee eee e eee ete e teen teen nes 392 1 Manuscript received by the Secretary of the Society July 31, 1909. XXXIII—Buut, Grou, Soc, AM., Vou, 20, 1908 (369) 370 ©&.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS Page ScChHoemfies o's od & cis cha. Od 3 ee aie eres oe ee ere eee 393 IMEVOTS A205 were, oem oie one 6 fe cose a ayeveley ae atekepn ay erage telefon 394 Relation of the divisions proposed to those of preceding authors...... 394 SSUMINATY s2 So 5 oslo a,» oes e's Scere d= ase siete co peteyaGe re beliels let ene tetas ee 397 INTRODUCTION The modern classification of crystals into thirty-two groups is a highly important addition to our knowledge of the subject of crystallography, as well as a valuable contribution to the field of natural science. We are indebted to many investigators for the development of this classification, chief among whom are Hessel, Bravais, Moebius, Gadolin, Curie, Fedorow, and Schoenflies. While Hessel was the originator of the classification, his work, unfortunately, was long neglected, and it was not until Gadolin, Schoenflies, and others had given independent develop- ments of the subject, that crystallographers came to recognize the impor-. tance of their work. While the classification of crystals into thirty-two groups rests on a sound and philosophical basis, 1t is probable that many have found its presentation, especially to elementary students, attended by certain diffi- culties, chief among which are the multiplicity of the types of symmetry of the thirty-two groups and the consequent lack of a clear conception on the part of the student of the relations which exist among them. Though developed, as so elegantly expressed by Gadolin, by the applica- tion of a single principle, the method by which this has been done histor- ically is too intricate to be employed in an elementary presentation of the subject. If, however, the use of this principle is abandoned and the groups of symmetry are treated as separate units, the student fails to comprehend one of the most important elements in the classification of crystals, namely, the development of the thirty-two groups by the applica- tion of a single principle—a result which seems to the author most unfor- tunate and which leads to embarrassment, because of the failure to per- ceive the larger relations which exist among the groups of symmetry as well as the unity of the subject. It is the purpose of the author to give, in the following communication, an elementary development of the thirty-two groups of crystals which leads to the recognition of seven fundamental types of symmetry of erys- tals. It is believed that the recognition of these seven types of symmetry not only greatly simplifies the discussion, but emphasizes relations among the groups of crystals which have not hitherto been clearly recognized. These seven types of symmetry were recognized in part by Hessel, who INTRODUCTION STi defined them by his seven types of axes and who referred to them all crystals with a principal axis. While he developed this classification consistently in crystals with a principal axis, he did not succeed in fol- lowing it in the Isometric system, where he adopted another principle. Had he recognized these types in that system also, he would have largely - anticipated the results here given. The author’s development is, however, independent of that of Hessel, with whose methods he was not acquainted at the time of its origination, while the method used differs from Hessel’s in its simplicity and brevity. It is, however, encouraging to find so large an agreement between the results obtained by Hessel and by the writer. We are especially indebted to Schoenflies, from the reading of whose | work we were led to the conceptions here presented and with whose ‘method of development that proposed has some features in common. Certain conclusions of the author are related to those of Miers. They were, however, developed before the appearance of that author’s work. These types have been more or less clearly recognized by many in closely related systems, such as the Trigonal, Tetragonal, and Hexagonal, but their occurrence in all systems does not seem to have been shown by others before this.* The discussion will consist of two parts: I. A proposed classification of crystals. II. An historical review, giving an outline of the earlier development of the thirty-two groups and their relation to the author’s results Part I: PROPOSED CLASSIFICATION OF CRYSTALS PRELIMINARY CONSIDERATIONS Before discussing the proposed classification it is desirable to present certain preliminary considerations. Definitions—Singular direction.—A singular direction in a crystal is one about which the arrangement of parts and properties differs from that about every other direction in the crystal. Thus, in a crystal of the Hexagonal system, the ¢ axis is a direction about which the properties differ from those about every other direction in the crystal—that is, it is a singular direction and is not duplicated by any other line. Elements of symmetry.—It is often convenient to have a word which includes both axes and planes of symmetry. We will define an axis or plane of symmetry as an element of symmetry (the “basis of symmetry” of Moebius). * This classification is published only after it has been in use in teaching for a num- ber of years and its value shown by experience, 3072 + =6(¢c. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS Theorems.—Axes or planes of symmetry must necessarily intersect symmetrically, since all parts are symmetrically disposed with reference to them. We have the following theorems concerning their combinations : 1. The least number of axes of symmetry that can enter into combination is three. Two only can not combine.’ 2. If a singular axis be intersected by other axes, then the latter are (@) in number equal to period of singular axis; (0) in period, two-fold; (c) in position, perpendicular to the singular axis. (See figure 1, where a four-fold axis is intersected by 4 two-fold axes.) Proof: (a) If lateral axes are present, their number equals period of singular axis, since all parts are repeated about any axis as often as its period. For example, three axes occur about a three-fold axis, four about a four-fold axis, etcetera. (0b) If the lateral axes were not ito -fold, the singular axis would be re- peated in a new position—that is, it would not be singular. Thus it would be repeated three times about a three-fold axis, etcetera. Aa at Ficure 5.—Alternating Ficure 1.—Singu- FiecurE2.—Repetition Ticure3.—Trigonal axes Fieure 4.—Axis of sym- axis developed by alter- lar axis with 4lat- of singular axis about developed by equal rectan- metry developed at inter- nating axes and symme- eral axes. oblique axis. gular axes. section of symmetry planes. try planes. (c) If the accessory axes were oblique to the singular axis, the latter would be repeated in a new position—that is, it would not be sin- gular. Thus, in figure 2, the singular axis SS would be rotated to position S’S’ about an oblique axis aa and no longer be singular. 3. Intersection of equal axes.—If equal axes intersect, then (a) The least number of such axes is three. (See theorem 1.) (0) If the three axes are equal, they are rectangular, since each axis is equally distant from the others if all are equal—that is, perpen- dicular to them. (c) If rectangular, their periods can be two or four only. Three and six- fold axes can not produce 90 degree positions, since they must intersect at 120 or 60 degrees. (d@) Four trigonal axes are present, equally distant from the three equal axes and intersecting in the center of figure. They are the signs of the equality of the three axes. (See projection, figure 3.) 4. Intersection of axes and planes of symmetry. (a) The intersection of several axes of symmetry lying in one plane pro- duces an axis of symmetry at their point of intersection whose period equals their number. (See figure 1.) This is the converse of theorem 2a. 2See proof of this. very elementary proposition in Groth’s Physikalische Krystallo- graphic, fourth edition, 1895, pp. 315-316. BASIS OF CLASSIFICATION 373 (6) Several planes of symmetry intersecting in one line produce an axis of symmetry at their intersection whose period equals the number of intersecting planes. Thus, in figure 4 it is readily seen that the intersection of the three planes will repeat the point @ at a’, and this pair of points will appear in three similar positions— that is, they are repeated three times about the line of intersec- tion, which becomes, therefore, a three-fold axis. : (c) The intersection of alternating planes and axes in one line produces an axis of alternating symmetry at their intersection whose period equals the number of intersecting axes and planes. An ordinary axis of half that period will coincide with the alternating axis. This law is readily seen by the repetition of the point # in fig- ure 5. : We may express the theorems a, b, c by the statement that the intersection of several axes or planes of Symmetry produces an axis of symmetry at their intersection whose period equals the number of intersecting elements. If axes or planes only intersect, it is an ordinary axis; if alternating axes and planes intersect, it is an alternating axis. 5. Possible periods.—The only periods axes of Symmetry can possess in crystals are 2, 3,.4, 6. This springs directly from the law of the Ration- ality of Parameters. Its proof is too full to be given here. (See Groth’s Physikalische Krystallographie, fourth edition, 1895, page 313. ) DEVELOPMENT OF CLASSIFICATION Basis of classification.—The basis of classification is symmetry. Crys- tals have been classified upon the basis of the crystallographic axes, as is done in the ordinary definition of the systems of crystals. These are, however, imaginary mathematical lines, existing only subjectively in the mind of the observer and developed by him for convenience sake. They are not present objectively in the crystal and can not, therefore, form a natural basis for the classification of crystals. That they are arbitrarily determined is seen by the fact that the same crystal may be referred to several different axes, as in the use of the axes of Miller and Bravais in the Trigonal system. Symmetry affords a natural basis for the classification of crystals, being expressed by the elements of symmetry which are objectively present in the crystal. Moreover, symmetry is expressive not only of the geometrical form, but of the relations of the physical properties as well, and probably springs from the arrangement of the atoms and molecules in the crystal.* It is, moreover, the basis upon which the modern classification has been 3 See recent articles of Barlow and Pope in Journal of the Transactions of the Chemi- eal Society of London, vol. 89, 1906, p. 1675, and vol. 97, 1907, part ii, pp. 1150-1214. See also abstracts in American Chemistry Journal, vol. xxxvii, 1907, p. 638, and vol. xlii, 1909, p. 158. 374 C. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS historically developed. It is, therefore, that which is accepted in the fol- lowing discussion. Types of symmetry—Symmetry may be defined as the repetition of similar parts and properties in a crystal. It may be produced in two fundamental ways: I. By rotation about an axis, termed symmetry by rotation. II. By reflection about a plane or planes, termed symmetry by reflec- tion. A third type (III) is produced by the combination of simultaneous rotation and reflection by which points, in rotating, oscillate alternately from upper to lower positions in a crystal, and vice versa. Such an axis may be termed an axis of combined rotation and reflection, or, more sim- ply, an alternating axis. It may be considered a combined axis and plane normal to it. This is the “zusammengesetzte” symmetry of Fedorow. We will now consider classes which develop in each type of symmetry. Sts a ca ‘ ’ » 2 yy sy Sz as ts ee. = a 4a “ss Lip & : F : A . P : ’ ‘ - : siya? : Ss Fiever6.—Axial Ficure7.—Polyaxial Fieunr 8.—Orithoaxial Fieure 9.—Repetition of FievRe 10.—Hedral class. class. class. singular axis by oblique class. plane of symmetry. Development of groups and classes of crystals. I. Symmetry by rotation. Rotation may be about one axis or many axes. 1. Rotation about one axis—Avial class* (figure 6). Rotation may occur about one axis, producing crystals having a single axis of symmetry. The axis may have periods of 2, 3, 4, 6 only, according to the law of the Rationality of Parameters, pro- ducing four groups of crystals. (See table, page 377, for summary.) All these crystals have one axis of symmetry and are singly terminated. The name suggested for this class is Axial (azon = an axis). 2. Rotation about many axes—Polyazial class (figure 7). Rotation may occur about many axes, producing crystals con- taining many axes of symmetry. Two possibilities are presented* a. A singular axis is present. Its periods may be 2, 3, 4, 6, according to the law of the Rationality of Parameters. The number of the lateral axes equals period of singular axis. b. No singular axis is present. There are three equal axes whose periods are 2 or 4. * This class may also be termed Monaxial instead of Axial, since it has only one axis of symmetry and all of its crystals are singly terminated. DEVELOPMENT OF GROUPS AND CLASSES 375 These crystals are doubly terminated, producing right- and left- handed forms which are enantiomorphous, and all manifest circu- lar polarization. They are termed Polyaxial (polus=many, axon = an axis). Il. Symmetry by reflection about planes. The second fundamental type is symmetry by reflection. Method of development.—lIt has already been shown that when planes of symmetry intersect they produce an axis of symmetry at their intersec- tion. It is therefore necessary that the axes so formed should be iden- tical with those already discussed. The simplest way of developing these classes, therefore, is to take the preceding axis and pass planes of sym- metry through them, employing first one axis, then many axes. | A.. One axis.—Planes may be passed through one axis in two positions. 3. Plane normal to the axis—Orthoazial class (figure 8). The axis may possess the periods 2, 3, 4, 6, giving rise to four groups. These crystals are doubly terminated, the upper faces being directly over the lower while the plane is norma] to the axis. The class is hence termed Orthoaxial (orthos = perpendicular, and axon = an axis). A plane of symmetry can not pass obliquely to a single axis, otherwise the axis would be doubled by reflection, as shown in figure 9, where the axis SS is reflected to position S’ S’—that is, - the crystals would no longer possess a single axis. One other pos- sibility, therefore, remains. 4. Planes parallel to the axis—Hedral class* (figure 10). Planes of symmetry are passed parallel to the axis which is pro- duced by their intersection, its period equaling the number of in- tersecting planes. These crystals are singly terminated and have their faces in pairs in the general form (mPn). They possess planes of sym- inetry intersecting in one axis. The class is termed Hedral (hedra =a plane), since the axis is but the result of the intersec- tion of the planes. B. Many axes.—We may now pass planes through many axes. Planes may be passed through them in two positions only, either coinciding with the axes or alternating with the axes. 5. Planes coinciding with the axes—Orthohedral class} (figure 11). Here the planes pass through the axes which are formed at their intersections. Having many axes, two possible cases present themselves : a. A Singular axis is present with periods of 2, 3, 4, 6. * This class may also be termed Monaxihedral (having planes intersecting in one axis) or, for simplicity, Monohedral (singly terminated pyramids of the hedral type). { This class may also be termed Polyhedral ; that is, having many planes of symmetry. 47) eG kK. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS b. No singular axis is present. Three equal axes with periods of 2 or 4. Crystals of this class are doubly terminated, the faces of the upper pyramid being directly over those of the lower. Its sym- metry may be derived from that of the Hedral class by passing a plane of symmetry normal to the planes of symmetry of that type. It is hence named Orthohedral (orthos = perpendicular, hedra =a plane). 6. Planes alternating with the axes—Amebahedral class (figure 12). Vertical planes of symmetry may be passed between the lateral axes with which they then alternate, developing an alternating axis at their intersection. Since the smallest number of lateral axes is two, alternating with two planes, the lowest possible period is 4. Having many axes, two possibilities are presented: a. A singular axis is present with periods of 4 or 6. ‘ : Rees a ; : i | ‘ R mull ; ; Fieure 11.—Orthohedral Fievurs 12.—Amebahedral Fieurk 13.—Amebaxial Figure 14.—Three-fold alter- class. class. class. nating axis producing orthohe- dral symmetry. b. No singular axis present. Three equal axes occur with periods of 4. These crystals possess alternating vertical planes and horizontal lateral axes of symmetry, while their faces alternate about the vertical axis. They are hence termed Amebahedral (amoibos = alternate, hedra=a plane). This manifestly exhausts all possible types of symmetry due to reflection about planes. Ill. Symmetry by combined rotation and reflection. In addition to the preceding, it is possible to combine rotation and reflection simul- taneously in one act, producing a third type of symmetry. This is the combined (zusammengesetzte) symmetry of Fedorow. A single class de- velops here. 7. Amebazial class (figure 13). These crystals are without ordinary axes or planes of sym- metry, but possess a single axis of alternating symmetry. This fact may also be expressed by stating that they have a combined axis and plane of symmetry normal to it, or, more simply, that they have a single axis of alternating symmetry. This axis can have periods of 2, 4, 6 only. A three-fold alter- nating axis is impossible. If assumed, it will produce faces which are directly over each other—that is, they will not be alternating. (See projection, figure 14.) SUMMARY OF DEVELOPMENT 377 Crystals of this class possess an alternating axis about which the faces of the crystals alternate, and are hence named Ame- baxial (amoibos = alternating, avon = an axis). The above manifestly exhausts all possible combinations of axes and planes of symmetry with periods of 2, 3, 4, 6, producing thirty groups of symmetry. ‘'I'wo other types of symmetry are possible: 1. Forms possessing a plane of Symmetry only. They may be viewed as containing a one-fold axis parallel to the plane, and hence referred to the Hedral class—one-fold. 2. Forms without symmetry, the asymmetric group of Groth. They are reproduced by a rotation of 360 degrees about a one-fold axis, and © hence may be referred to the Axial class—one-fold. This manifestly exhausts all possible types of symmetry produced by rotation and reflection in forms having periods 1, 2, 3, 4, 6. Thirty-two groups of symmetry are thus seen to be developed, occurring in seven classes. Summary of development.—The results reached and the periods of each class are exhibited in the following table: Period of Axis. Singular axis. No singular I. Symmetry by rotation about an axis. axis. EON CU ANIS——=AlV Lh. Bei ere brane, shee evacuees 0 1,2, 3.4, 6 2. Many axes—Polyawial ............:: 2, 3, 4, 6 2,4 Il. Symmetry by reflection about planes. A. One axis: 3. Plane normal to axis—Orthoazial.... 2, 3, 4,6 4, Planes parallel to axis—Hedral..... 1, 2, 3, 4, 6 B. Many axes: 5. Planes coincident with axes—Ortho- COTO recent oie cud aiaitai ein ere eabeistenciens 2, 3, 4,6 2, 4 6. Planes alternating with axes—Ameba- WCOTQUIRS is haisie os lagstetcie so are, cape ee els —,-, 4,6 -—,4 III. Symmetry by combined rotation and reflection. 7. Alternating axis only—Amebawial.... 2,-, 4, 6 REFERENCE OF THE CLASSES TO THE ACCEPTED SYSTEMS OF CRYSTALS We may inquire what relation the preceding development bears to the crystal systems. An examination of the above table shows that the groups fall into natural assemblages, based upon the character and period of their axes of symmetry. These are the accepted systems, as follows: 1. Crystals possessing no singular axis of symmetry, characterized by three equal axes, constitute the Isometric system, which develops in two- and four-fold divisions. 2. Six-fold groups—Hexagonal system. 3. Four-fold groups—Tetragonal system. 4, Three-fold groups—Trigonal system. 378 C. K. SWARTZ—-PROPOSED CLASSIFICATION OF CRYSTALS The remaining two- and one-fold groups might have been classified into two- and one-fold systems respectively. They have, however, been divided according to the number of fixed directions of symmetry (determining the number of their rectangular directions), as follows: 5. Possessing three fixed directions of symmetry—Orthorhombic sys- tem. 6. Possessing one or two fixed directions of symmetry—Monoclinic system. 7. Possessing no fixed direction of symmetry—Tricliniec system. The various systems are thus seen to spring from the above develop- ment. The members of one system and one class constitute a group of crystals. The relations of the various classes and systems are shown in plates I and II.4 The first plate shows the general form (mPn) in each group; the second the spherical projections of the symmetry of each group. The character of the symmetry of each class is illustrated in the first vertical column. CHARACTERISTICS OF THE SEVEN CLASSES The characteristics of the seven classes may be exhibited by arranging them in a slightly different manner from that in which they were devel- oped. They are seen to comprise two distinct types—(1) axial, (II) hedral. 7 I. Axial classes. The axial classes have pyramids produced by rotation. ‘They are char- acterized by the fact that the faces of the general form (mPn) are single, never in pairs, about the axis of rotation. They develop first, second, and third order forms, the latter being both right- and left-handed. 1. The Agial class contains singly terminated pyramids possessing a single axis of symmetry. The other axial classes consist of two such pyramids joined base to base. This may be done in three ways. The faces of the upper pyramid may be 2. Directly over those of the lower pyramid—Orthoazial class; 3. Obliquely over those of the lower pyramid, being rotated either to the right or the left hand, producing right- and left-handed forms— Polyazial class ; 4. Alternating with those of the lower pyramid (the faces of the upper pyramid being over the edges of lower pyramid )—Amebvazial class. Il. Hedral classes. The hedral classes, on the contrary, have pyramids produced by reflec- tion about vertical planes of symmetry (as usually held). The faces of the general form (mPn) hence occur in pairs about these planes, produc- ing di-forms (di-pyramids, scalenohedra, etcetera). *The monoclinic crystals are drawn with axis of symmetry vertical to show their rela- tions better to crystals of other systems. CHARACTERISTICS OF THE SEVEN CLASSES 379 5. The Hedral class consists of singly terminated pyramids having faces in pairs. Two such pyramids may be joined base to base, pro- ducing the other hedral classes. The faces of the upper pyramid may be 6. Directly over those of the lower pyramid—Orthohedral ; 7. Alternating with those of the lower pyramid—Amebahedral. The oblique position corresponding to that of the Polyaxial class can not exist in this type, since the planes of symmetry of the upper and lower pyramids would not coincide, violating the law of Parallel Directions. These relations are exhibited in the following tables: Table showing Forms of Classes Doubly terminated Direct Oblique Alternate Singly (Horizontal (Horizontal (Attonnat terminated sa se eee axis) Axial Orthoaxial Polyaxial Amebaxial (Faces single X in mPn) Hedral Orthohedral Amebahedra] Hedral bral f /, Bete iaupairs VAN dy Table showing Symmetry of Classes Doubly terminated Cw se eS Direct Oblique Alternate Horizontal + eo een Seana ea) (itaraaiieg terminated symmetry) symmetry) axis) Axial Orthoaxial Polyaxial Amebaxial Axial (Faces single in mPn) Hedral Orthohedral Amebahedral Hedral (Faces in pairs in mPn) 380 C.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS An examination of the above table shows that the seven classes fall into pairs of two members each, which differ in that the axial have single and the hedral double faces in the general form (mPn). Thus in the Ortho- axial class we have third order pyramids, and in the Orthohedral class di-pyramids ; the third order rhombohedron of the Amebaxial class corre- sponds to the hexagonal scalenohedron of the Amebahedral class having faces in pairs, etcetera. ‘There is, however, no hedral class corresponding to the Polyaxial class, which thus stands alone. LARGER DIVISIONS OF CRYSTALS In addition to the systems and classes, the above development. shows (see plates I and II) that certain larger divisions occur, expressing the fundamental geometrical and physical properties of crystals. These major divisions are three in number. We here term them the Isometric, Dimetric, and Trimetric divisions respectively. Isometric division——This comprises all crystals having no singular direction. Their crystallagraphic axes have hence one unit of length. Their optical properties are alike in all directions and their elasticity fig- ure is a sphere. Dimetric division.—This comprises crystals having one singular direc- tion. Their crystallographic axes have hence two units of length. They are optically uniaxial. Their elasticity figure is an ellipsoid. Trimetric division.—This comprises crystals having three or more sin- gular directions; hence their crystallographic axes have three units of length. They are optically biaxial. Their elasticity figure is the tri- axial ellipsoid of Fresnel. These divisions correspond to and express the fundamental physical and geometrical properties of crystals. They are the same as those developed by Hessel, although expressed in other terms. We are thus led by the preceding development to divisions representing the larger geometrical and physical units in crystals. INTEGRITY OF THE SEVEN CLASSES OF CRYSTALS The foregoing discussion shows that the seven classes of symmetry are well defined and natural units each containing forms having a single type of symmetry. ‘This conclusion is supported by the following consider- ations : 1. Their development, already sketched, shows this fact. 2. It is also shown by the fact that the members of one class possess: common geometrical properties. Thus the Scalenohedral group of the Hexagonal system, the Scalenohedral group of the Tetragonal system, and the Hextetrahedral group of the Isometric system are members of one INTEGRITY OF THE CLASSES 381 class. All are very closely related and form a natural unit. The same is true of the members of other classes. ‘The Isometric groups do not differ in any essential way from the other members of the classes to which they are referred, the only difference being the repetition of the faces about the three-fold axis. © 3. Again, all the members of one class are closely related physically. Thus all the Polyaxial groups manifest circular polarization, the members of the Hedral class show hemimorphic physical properties, etcetera. 4. The members of each class possess a single type of symmetry, as seen in the spherical projections of plate 31. Definition of class—For the unit so described we propose the term class. It may be defined as follows: A class of crystals 1s the sum of all crystals having similar combinations of elements of symmetry. ‘Thus all the members of the Axial class have one axis of symmetry; members of the Orthoaxial class, one axis and a plane normal to it, etcetera. The discussion given above is seen to lead to an elementary development of the thirty-two groups, the recognition of seven classes of crystals, the development of the seven systems, and the recognition of the larger and more fundamental divisions which correspond with the physical and geo- metric properties of crystals. ELEMENTARY DEVELOPMENT It is possible to give a still simpler development of the preceding classi- fication, for the use of elementary students, which it may be desirable to outline here, in addition to that already presented. Although certain of its features have been stated in the foregoing discussion, they will be re- stated here for the sake of clearness and brevity. Symmetry has been defined as the repetition of similar parts and prop- erties in a crystal. It may be of two types: I. Symmetry by rotation about an axis. II. Symmetry by reflection about a plane or planes. In the first type planes occur singly, about the axis of rotation. In the second type planes occur in pairs in the general form (nPn). I. Symmetry by rotation.—If an inclined plane be rotated about a vertical axis, it will produce a singly terminated pyramid, the number of whose sides equals the period of the axis. It may be rotated into any position about the vertical axis-producing pyramids of the first, second, and third orders. Atal class. Two such pyramids may manifestly be joined base to base, producing double pyramids. This combination may be effected in three different ways: 382. C.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS 1. The faces of the upper pyramid may be directly over those of the lower pyramid. This type has a horizontal plane of symmetry and is called the Orthoazial class. 2. The faces of the upper pyramid may be above the edges of the lower pyramid—that is, the faces of the upper and ‘lower pyramid alternate about the vertical axis, which then becomes an alternating axis—Ameb- axial class. ; 3. The upper pyramid may be obliquely over the lower pyramid, being turned through some angle intermediate between those of the two preced- ing classes. Such rotation may be either to the right hand or the left, giving two kinds of forms, termed right- and left-handed respectively. They possess horizontal axes of symmetry—Polyazial class. IT. Symmetry by reflection about a plane or planes.—Let several planes intersect in a vertical axis. The period of the axis will then equal the number of intersecting planes of symmetry. Any inclined crystal face will be reflected about the planes of symmetry, producing a singly terminated pyramid whose faces are in pairs, the num- ber of pairs being equal to the number of the vertical planes of symme- try—Hedral class. | Two such pyramids may be combined base to base, producing doubly terminated pyramids. This may occur in two ways: 1. The upper pyramid may be directly over the lower. A horizontal plane of symmetry develops, while axes of symmetry are developed at the intersection of the planes of symmetry, the axes being precisely like those of the Polyaxial class—Orthohedral class. 2. The faces of the upper pyramid may be over the edges of the lower pyramid—that is, the faces of the upper and the lower pyramid alternate about the vertical axis. Horizontal axes of symmetry develop between the vertical planes of symmetry. The vertical axis is therefore an alter- nating axis whose least possible period is four, since the smallest possible number of lateral planes plus axes is four (two of each)—Amebahedral class. The intermediate position, corresponding to that of the Polyaxial class, can not occur, since the planes of symmetry of the upper and lower pyra- mid would not coincide, violating the law of Parallel Directions. There are thus seven classes of symmetry, and seven only, possible. Periods of the axes of symmetry.—It will be observed that three of the classes—Polyaxial, Orthohedral, and Amebahedral—have many axes of symmetry. All classes may develop a singular axis with periods of 2, 3, 4, 6, and the three classes with many axes may develop in addition three equal axes having periods of 2 or 4, save that the alternating types have ELEMENTARY DEVELOPMENT 383 no three-fold period and the Amebahedral class no period less than four. In addition to the preceding we may also have one-fold Axial and one- fold Hedral forms. Thirty-two groups are developed in this manner. ‘They are summa- rized in the following table, the periods possible in each class being given below its name. Sinely Doubly terminated terminated Direct Oblique Alternate Axial Axial Orthoaxial Polyaxial Amebaxial Nees 2, 3, 4, 6 Py Big Ay Oy Page 2,-4,6 Hedral Hedral Onthowedrale sds tye soe Amebahedral 2 4G DMO OAR Gul eh Shain ea 4,6, 4 The reference of the groups to the various systems may then be devel- oped as outlined in the preceding paragraphs. INFERENCES It may be of interest to give certain deductions springing from the pre- ceding discussion. Relate rank of classes and systems.—The classes appear to be more natural in character than the systems. ‘They are certainly less artificial than the systems, if the latter are made, as has been generally the case, to depend upon the crystallographic axes, which are imaginary lines sub- jectively present in the mind of the student. This is well seen in the difference in usage in the T'rigonal system, where the axes of Miller or Bravais can be employed equally well. It is also quite possible to refer the Hexagonal and Trigonal forms to orthorhombic axes, as frequently done by Barlow and Pope in their recent paper, “The relation of crys- talline form and chemical constitution.”® The classes, on the contrary, depend upon the axes and planes of symmetry objectively present in the crystal, and are hence natural units. Relatwe rank of the systems.—The various systems do not appear to be coordinate in value, but represent divisions of different rank. Thus the Isometric system is coordinate with the Dimetric division comprising crystals of the Trigonal, Tetragonal, and Hexagonal systems, and also with the Trimetric division. This is also shown by the optical proper- ties, in which respect the Isometric system corresponds to the Uniaxial and Biaxial divisions of crystals. ike those divisions, it may he sub- divided on the basis of period, yielding two-fold and four-fold sections. 5 Journal of the Transactions of the Chemical Society, vol. 91, 1907, part 2, pp. 1150- 1214, and vol. 94, 1908, p. 1528. 384 Cc. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS Again, the Orthorhombic, Monoclinic, and Triclinic crystals are divided on a different basis from that employed in making the subdivisions of dimetric crystals. The systems therefore appear to differ in rank. Relations of the rhombohedral and_ scalenohedral groups.—These groups contain both a three-fold common and a six-fold alternating axis, and hence may be referred, on the basis of period, to either the Trigonal or Hexagonal system. While they have generally been referred to the Trigonal system, it seems clear to the author that their natural place is in the Hexagonal system, where he has placed them, for the following reasons : The group containing the third order sphenoid of the Tetragonal sys- tem is unquestionably four-fold. Dana makes it two-fold; Groth, four- fold. Groth’s position seems correct. It possesses no center or planes of symmetry, and it is impossible to develop it about an axis of two-fold period. If the third order sphenoid, possessing four faces, is four-fold, the analogous third order rhombohedron, with six faeces, should have a higher period, becoming six-fold. It is quite clear that the third order rhombohedron bears the same relation to the Hexagonal system that the third order sphenoid does to the Tetragonal system. The Tetragonal character of the third order sphenoid is unquestioned. A consistent in- terpretation would seem to refer the third order rhombohedron to the Hexagonal system. Again, the Tetragonal and Hexagonal scalenohedra are the precise analogues of the third order sphenoid and third order rhombohedron, and their position is determined in the same manner. It seems fitting that the analogous forms of the Tetragonal and Hexagonal systems should be classified in the same manner. The third order rhombohedron can not be developed about a trigonal axis without an appeal to a center of symmetry. It will be noticed that, in all other forms, the results obtained by the use of a center of symmetry spring directly from the axes and planes of symmetry as here employed. It does not seem desirable to appeal to a center of symmetry in this case only. Again, that the alternating axis is the dominant axis is indicated by the fact that the highest occurring period, six-fold, is that of the alter- nating axis, in harmony with the law of the Rationality of Parameters. It thus seems best to refer these groups to the Hexagonal system, giv- ing a consistent development to Trigonal, Tetragonal, and Hexagonal sys- tems and bringing out the evident close analogy between them. . Center of. symmetry.—The development employed has rendered it un- necessary to use the center of symmetry as an independent element of ADVANTAGES OF THE METHOD 385 symmetry. It is manifestly secondary, being produced by the planes and axes of symmetry. It is unnecessary to retain it as a distinct element of symmetry. ADVANTAGES OF THE METHOD The classification outlined in the foregoing discussion is believed to possess certain advantages. It is based on symmetry, the basis of the modern development of crys- tallography. It recognizes the likeness of closely related groups and points out the - analogies between them. | It recognizes seven instead of thirty-two units and develops all by one general method. The name of the class suggests both the symmetry and crystal form. It introduces few new names, and these it is believed are significant. It does not displace accredited names. It expresses the larger physical and geometrical relations which exist among crystals. Tt is in harmony with the fundamental mathematical development of the subject. It is elementary, and is readily followed by the elementary student. Part II: Historican REVIEW REVIEW OF THE DEVELOPMENT OF THE THIRTY-TWO GROUPS OF CRYSTALS _* Work of previous investigators——The classification of crystals into thirty-two groups constitutes one of the most important contributions to the science of crystallography. It was developed by the labors of a num- ber of independent investigators, chief among whom are Hessel, Bravais, Moebius, Gadolin, Curie, Fedorow, Minnigerode, and Schoenflies. An outline of their work will be given and its relation shown to the classifica- tion proposed in the preceding pages. Their results will be discussed somewhat more fully because of the great historic interest of the subject. All of these investigators have had one aim, to predict all forms of erystals which may possibly occur. The basis of their investigations has been the conception of symmetry, of which all have recognized two funda- mental types: (1) symmetry produced by a repetition of identical parts by rotation; (2) symmetry produced by the repetition of similar parts by reflection, together with various combinations of these two processes. With respect to their methods, the investigators form two classes: (1) those who have first sought to develop all possible types of symmetrical figures, and then to determine which of these may occur in crystals, in harmony with the law of the Rationality of Parameters, the fundamental XXXIV—BULL. Grou. Soc. Am., Vou. 20, 1908 886 C.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS law of crystallography; (2) those who have sought to develop only the forms which are possible in crystals under the above named law. To the first class belong Hessel, Bravais, Moebius, Curie, Fedorow, and Minnigerode; to the second, Gadolin and Schoenflies. Hessel.—The founder of the modern classification of crystals is J. F. C. Hessel, whose results were published in an article entitled “Krystall,” in Gehler’s Physikalisches Worterbuch, in the year 1830.° Unfortunately Hessel’s results long rested in obscurity and were prac- tically overlooked. It is only recently that they have begun to be appre- ciated at their true worth. Hessel based his discussion upon the conception of symmetry, of which he recognized two types, ebenbildlich (having the same form) and gegen- bildlich (likeness by reflection) .” Hessel’s method is to develop first all possible symmetrical figures, and then, secondly, to determine which of these are possible in crystals. To do this he shows first that there are seven types of axes about which all symmetrical figures may be developed. The types are as follows :® Types of Axes Ends unlike (ungleichendig). } Se aa Forms opposite (gleich- Simple (einfach). stele) 2.3 aera Double (zweifach). Ends alike Alternate { Simple (einfach). (gleichendig). } Forms not opposite (un- (gerenstellig). 1 Double (zweifach). : Ad ee ae Oblique Simple (einfach). (ebenbildlich). The axes are classified accordingly as they are dissimilarly terminated (ungleichendig) or similarly terminated (gleichendig). The latter are divided into those in which the upper faces directly overlie the lower (gleichstellig) or not. The last type is subdivided into those in which the upper faces alternate with the lower (gerenstellig), or are obliquely 6 Bd. v, Ab. ii, pp. 1023-1360. A separate edition of this article was issued in 1831 under the title “Krystallometrie oder Krystallonomie und Krystallographie.” This work is reprinted in Ostwald’s “Klassiker der exakten Wissenschaften,” no. 88, 1897. An admirable review of Hessel’s results is given by L. Sohncke, “Die Entdeckung des Hintheilungsprincips der Krystalle,” Zeitschrift fiir Krystall., bd. 18, pp. 486-498, 1891. 7 Article Krystall, cited above, p. 1035. Reprint, vol. i, pp. 20-21. 8 He develops his results by means of radii (“‘strahlen’’), which are lines drawn from the center of the figure to the symmetrical parts. He is thus able to discuss the posi- tion of these lines rather than the parts of the figures. Hessel does not recognize planes of symmetry, but develops the figures about axes which comprise in reality both axes and planes of symmetry. ® Article Krystall, pp. 1059-1060. Reprint, vol. i, pp. 44-45. See Sohncke, Zeitschrift fiir Krystall., bd. 18, p. 488, 1891. REVIEW OF DEVELOPMENT OF THIRTY-TWO GROUPS 387 over the lower, producing enantiomorphous forms (ebenbildlich). He recognizes thus four major types of axes: (1) singly terminated, (2) doubly terminated direct, (3) alternate, (4) oblique. ach of the first three types may coincide with a plane of symmetry or not, producing faces which are in pairs (zwelfach) or single (einfach). All possible symmetrical forms are next developed about the seven types of axes, by which means he arrives at all possible symmetrical fig- ures.?° Hessel now develops the law of the Rationality of Parameters,*? which he terms Das Gerengesetz, and shows that according to this the only axes possible in crystals are those possessing periods of 1, 2, 3, 4,6. Applying this law to the preceding forms, he shows that all crystals fall into 32, and only 32, groups of symmetry, of which a summary is given on pages 1280 to 1284 of his article.?? He divided all the groups, save those of the Isometric system, into seven types, according to the character of their dominant axis. Unfor- tunately he failed to carry his classification into the Isometric system, but was led to adopt another principle in it, namely, the number of similar radii in the crystal. The Isometric system was thus termed the eight- rayed (8-strahlig) system, its groups being as follows :18 Zweifach 8-strahlig (Hexakisoctahedral of Groth). Einfach 8-strahlig (Pentagonal Icositetrahedral of Groth). Zweifach 4-strahlig (Hexakistetrahedral of Groth). Einfach 4-strahlig (Tetart. Pent. Dodecahedral of Groth). Zweimal 4-strahlig (Dyakisdodecahedral of Groth). Had he succeeded in carrying his seven divisions into the Isometric system he would have largely anticipated the author’s classification. Un- fortunately, however, he failed to do so. Larger divisions of crystals——Hessel does not refer the thirty-two groups to the usual six (or seven) systems, but united them in four divis- ions, which he classifies as follows :14 I. Class without principal axes (Hauptaxenlos). Order 1. With four three-fold axes. II. Class with a principal axis (Hauptaxig). Order 1. Possessing one principal axis. Family 1. “One and three dimensional.” Family 2. “One and two dimensional.” Order 2. Possessing several different axes. “One and one dimen- sional.” 10 Article Krystall, pp. 1062-1157. Reprint, vol. 1, pp. 48-145. NU Ibid, pp. 1232-1276. Reprint, vol. ii, pp. 45-91. 12 Reprint, vol. fi, pp. 95-98. 18 Article Krystall, p. 1280. Reprint, vol. ii, p. 95. 4 Article Krystall, p. 1277. Reprint, vol. ii, pp. 92-93. 8388 co. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS The major divisions are seen to correspond to the isotropic and aniso- tropic crystals respectively, while the latter are subdivided into the un- axial (order 1), and biaxial (order 2) groups. His four minor divisions thus correspond to the Isometric system, Hexagonal (including Trigonal) system, Tetragonal system, and a fourth division, including the Ortho- thombic, Monoclinic, and Triclinic crystals. Hessel shows that these divisions are fundamental, not only geometrically but also physically, and harmonize with the optical and other properties of crystals which he clearly describes.*® Hessel’s discussion is obscure and very difficult to follow, not only because of its length and involved character, but also because of the many technical terms which he introduces. While his results are of the highest order of importance, they were long forgotten and unappreciated. It is only recently that they have been recognized and estimated at their true worth."® Bravais—In 1849 A. Bravais published in the Journal de Mathe- matique a discussion of the subject of symmetrical polyhedra entitled “Memoire sur les Polyhedres de Form Symmetrique.*’ Bravais was apparently without knowledge of Hessel’s previous work, to which he does not refer. Like Hessel, he endeavors to develop all possible symmetrical poly- hedra. This he does by considering symmetry with respect to a center, an axis, or a plane. He develops all possible types of symmetry in four divisions.*® I. Asymmetric. Class 1. Il. Symmetric without axis. Classes 2, 3. Period even. Classes 4-9. Period odd. Classes 10-16. IV. Spheroidal symmetry, no principal axes. Quaterternaire.—Forms possessing four-fold axes. Classes 17-21. Decemternaire.—Forms possessing ten three-fold axes. Classes 22-28. Ill. Symmetric with principal axis. He presents a series of theorems concerning all possible combinations of axes, planes, and centers of symmetry, developing finally twenty-three classes of symmetrical polyhedra*® in the preceding four divisions. Of these the twenty-second and twenty-third classes, containing the decem- ternaire forms of the above table, develop periods not possible in erystals. There are thus twenty-one classes of symmetry occurring in the four 15 Article Krystall, pp. 1277-1279. Reprint, vol. ii, pp. 93-94. 16 See article by Sohncke, Zeitschrift fiir Krystall., bd. 18, pp. 486-498, 1891. 17 Journal de Mathematique, Pures et Appliquées, vol. 14, 1849, pp. 141-180. Repub- lished in Ostwald’s Klassiker der Exakten Wissenschaften, no. 17, 1890. 18 Journal de Mathematique, vol. 14, 1849, p. 145. Reprint, pp. 12-13. 19 Tbid., p. 179. Reprint, p. 47. WORK OF BRAVAIS AND OF MOEBIUS 389 major divisions, which by changes in period develop thirty-one groups of crystals.?° Bravais’ discussion is elegant and simple, but he fails to develop one group, that containing the third order sphenoid of the Tetragonal system. He is concerned with the geometrical qualities of polyhedra rather than their application to crystallography. Moebius.—A. F. Moebius was engaged in the study of the properties of symmetrical figures at about the time of Bravais’ discussion. He pub- lished a brief article upon the subject** in 1851, in which he promised a full treatment of the question in the future. Although it is stated that his results were largely developed as early as 1852,?? his more complete dis- cussion was not published during his lifetime, but was issued as a posthu- mous work, by C. Reinhart, in 1886.*° Moebius seeks to develop all pos- sible symmetrical figures about a center, a line, or a plane of symmetry, arriving at the following divisions :** | I. Forms without axis of symmetry : 1. Center of Symmetry. Symbol O. 2. Plane of symmetry. Symbol E. II. Forms possessing a principal axis: 1. Symmetrical with respect to one axis. ad. Axis Simple. Symbol |, (n= period of axis). b. Axis alternating (‘“‘centrirte”’ axis), a combination of sym- metry about an axis and a center of symmetry. Sym- boliim: 2. Symmetrical with respect to two elements (termed by Moebius “pases”’) of symmetry : ad. Possessing two planes of symmetry. Symbol A. b. Possessing two axes of symmetry: 1. Ordinary axis. Symbol B. 2. Alternating principal axis and lateral axes. Symbol C. c. Possessing axes and center of symmetry: 1. Axis ordinary. Symbol D. 2. Axis alternating. Symbol D*. 20 Bravais uses the following symbols in his table of forms (ibid., p. 144; reprint, p. Dis C=centers of symmetry. /\= principal axis. li= lateral axes. L= first kind; lL.’ = second kind. a — plane of symmetry normal to principal axis. P= planes parallel to principal axis. P= first kind; P’ =second kind. 21 Uber das Gesetz der Symmetrie der Krystalle und die Hintheilung der Krystalle in Systeme. Ber. der Konigl. Sachs. Gesell. der Wissen., p. 349 (read in 1849). 22 Moebius: Gesammelte Werke. Herausgeg. von F. Klein. Leipzig, 1886, bd. ii, pp. 564-565. 23'Theorie der Symmetrischen Figuren. Moebius: Gesammelte Werke, 1886, bd. fi, pp. 563-708. 24 Tbid., pp. 642-647, where a summary is given of all save first division. 390 «a.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS III. Forms possessing several axes of period more than 2: 1. Tetrahedral forms (p. 653). Symbol T. 2. Hexahedral forms (p. 664). Symbol H. 38. Octahedral forms (p. 672). Symbol O. 4. Dodecahedral forms (p. 679). 5. Icosahedral forms (p. 692). All possible groups of crystals are found by substituting the periods 1, 2, 38, 4, 6 in the axes of the above divisions save the last two (Dodeca- hedral and Icosahedral), which produce no crystallographic groups, since the periods developed are not possible in crystals. In this manner Moe- bius arrives at twenty-eight groups of crystals only, four of the thirty-two groups being missing. (See table II, p. 396.) His discussion, while clear and simple is therefore incomplete. Gadolin.—The preceding authors have endeavored to develop all possi- ble forms of symmetrical polyhedra. Alexis Gadolin differed from them in restricting himself to the development of forms possible in erystals. This he did in a memoire published in 1871, entitled “Memoire sur la Deduction d’un Seul Principe de tous les Systems Crystallographiques avec leur Subdivisions.”?° His work possessed such elegance and fullness that it attracted widespread attention to the new conceptions concerning crystallography. Gadolin first?® develops all possible forms of symmetry about an axis, or a combination of axes, producing eleven groups of symmetry. He then develops symmetry about combinations of planes with the preceding axes, distinguishing three types.?* His results may be summarized as follows: I. Forms possessing axes of symmetry only: 1. Many axes, 6 groups. 2. One axis, 4 groups. 3. No axis, 1 group. II. Forms possessing axes and planes of symmetry: 1. Faces parallel, 11 groups. 2. Faces nonparallel (“Plane of symmetry’), 9 groups. 38. Alternating (“Sphenoidal’’) symmetry, 1 group. Thirty-two groups are shown to be possible in this manner, which are precisely the groups developed by Hessel. Gadolin next refers these groups*® to the ordinary six systems of crystals, classifying the groups as holohedral, hemihedral, hemimorphic, and tetratohedral. The entire dis- cussion is based upon the law of the Rationality of Parameters, to which he devotes especial attention in an appendix.?® 2 Acta Societatis Scientiarum Fennice Helsingforsie, vol. 19, 1871, pp. 1-71 (read in 1867). Reprinted in Ostwald’s “Klassiker der Exakten Wissenschaften,” no. 75, 1896. 26Tbid., pp. 11-15. Reprint, pp. 12-18. 2 Tbid., pp. 16-25. Reprint, pp. 19-31. 28 Ibid., pp. 25-41. Reprint, pp. 31-49. * Tbid., Appendix A. WORK OF CURIE AND OF FEDOROW 391 Gadolin’s discussion is so full and clear that for a time the origination of the entire conception of the thirty-two groups of crystals seems to have been attributed to him rather than to Hessel, whose work was generally neglected. While superior to Hessel in clearness and brevity, his work is much less extended. Moreover, he does not call attention either to the seven types of axes or to the large and philosophical grouping of that author. Curie-—In the year 1884 P. Curie published two papers®® in the Bulle- tin of the Mineralogical Society of France upon symmetrical figures. Curie develops all possible forms of symmetrical figures, of which he recognizes nine types and twenty-four subtypes.*t He then considers the possible crystallographic forms which possess the periods 1, 2, 38, 4,6. He finds that they are restricted to five of his types and eleven subtypes shown in the following table :*? III. Cubic (Isometric). 1. No planes of symmetry. 2. Planes of symmetry. IV. Tetrahedral (Isometric). 1. No planes of symmetry. 2. Planes and axes of symmetry coincident. 3. Planes and axes of symmetry alternate. VY. Forms possessing a double principal axis (that is, containing many axes). 1. No planes of symmetry. 2. Planes and axes of Symmetry coincident. 38. Planes and axes of symmetry alternate. VI. Forms possessing an inverse axis (that is, containing one axis only). 1. No planes of symmetry. 2. Planes of symmetry normal to axis. 3. Alternating planes of Symmetry normal to axis. 4. Planes of symmetry parallel to axis. IX. Forms possessing no repetition (that is, containing no axis). 1. No axis. 2. Center of symmetry. 3. Plane of symmetry. The different periods of the axes of symmetry in the above divisions give rise to thirty-two groups of symmetry possible in crystals, which are precisely the same as those found by the earlier investigators. Curie’s discussion is devoted to the geometric rather than to the crys- tallographic aspects of the subject. He calls attention to the fact that 30 Sur les questions d’ordre. Bulletin de la Société Mineralogie de France, vol. 7, 1884, pp. 89-118. Sur la Symetrie, ibid., pp. 418-457. 31 Ibid., p. 450, where a table is given. 82 Bulletin de la Société Mineralogie de France, table, p. 450. The subdivisions are found in the discussion, pp. 444-449. 392 +o. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS one group (the Tetragonal trisphenoidal group) is missing in Bravais’ table.*8 Fedorow.—Fedorow contributed a highly important discussion in 1885, entitled “Elementen der Lehren von den Figuren.”** His work, unfor- tunately, is in the Russian language, so that it did not at once gain the wide attention of which it was worthy. Fedorow gives a brief outline of his results in an article published in Zeitschrift fiir Kryst. in 1892.°° He states that his results are almost identical with those of Schoenflies, though obtained by different methods. He develops the thirty-two crystal groups in four major divisions, as fol- lows :*° I. With principal axis. 1. Hexagonal and Trigonal divisions. 2. Tetragonal division. 8. Division possessing two- and one-fold periods (including Ortho- rhombic, Monoclinic, and Triclinie systems). II. Without principal axis (Isometric). The subdivisions of these types are shown in table II, page 396. Fedorow introduces the conception of a combined axis and plane of symmetry (zusammengesetzte symmetrie) to produce the type of crystals frequently termed sphenoidal (alternating). Minngerode-——B. Minnigerode discussed all possible symmetrical fig- ures in a brief article in the Neues Jahrbuch for 1887.3" He develops symmetrical assemblages, which he terms groups, by the method of de- terminants, and finally restricts the forms arrived at to those possessing the periods possible in crystals. The divisions of crystals found by him are the following :*8 I. Derivatives of Octohedral group (Isometric system). Groups 1-5. Il. Derivatives of Dihedral group. 1. Possessing six- or three-fold period (Hexagonal system). a. Six-fold axis. Groups 6-10. bo. Three-fold axis and center of symmetry = six-fold period. Groups 11-12. c. Three-fold axis and center of symmetry = three-fold period. Groups 13-17. 2. Possessing four-fold period, or two-fold period and center of sym- metry = four-fold period (Tetragonal system). a. Four-fold period. Groups 18-22. 33 Tbid., p. 454. $4 St. Petersburg, 1885. > Vol. 20, 1892, pp. 25-715. 8° See synopsis by Schoenflies, Krystall Systeme und Krystall Structur, 1891, p. 104. 7 Untersuchung tiber die symmetrische Verhiltnisse der Krystalle. Neues Jahrb. fiir Min. Geol. und Pal. Beilage, bd. vy, 1887, pp. 145-166. $8 Ibid., pp. 157-164. WORK OF MINNIGERODE AND OF SCHOENFLIES 393 b. Two-fold period and center of symmetry — four-fold period. Groups 23-24. 3. Possessing two-fold period, with or without center of symmetry = two-fold period or without axis of symmetry. a. Orthorhombic. Groups 25-27. b. Monoclinic. Groups 28-30. ce. Triclinic. Groups 31-32. Thirty-two groups of crystals are obtained by employing the periods possible in crystals. Minnigerode’s results, though obtained by an independent method, coincide fully with those of the preceding workers. His discussion, while highly mathematical, is elegant and brief. Schoenflies—In the year 1891 A. Schoenflies published the most im- portant contribution to the classification of crystals (save perhaps that of Fedorow) since the memoire of Gadolin. His work, entitled “Krystall Systeme and Krystall Structure,’*® is devoted to the discussion of the geometrical form and inner structure of crystals. Like Gadolin, he restricts his discussion to the forms possible in crys- tals under the law of the Rationality of Parameters. He recognizes sym- metry of two kinds :*° A. Symmetry by rotation, which he terms symmetry of the first kind. B. Symmetry by reflection (variously combined with rotation), termed symmetry of the second kind. Forms of the first kind possess an axis of symmetry only. Forms of the second kind are produced by passing planes in various positions through the axes of the first kind. The following table*t shows his divisions : I. Possessing axes of symmetry only. II. Possessing planes combined with 1. Noaxis. Identity. (C,. axes of symmetry. re ; ye Plane horizontal. C®. 2. One axis. Oyche. Cn. (CO SHES o Moobee Plat cevonticall Ww. 3. Several axes, one principal. Woven Plane horizontal. V#®. eniod)2,, Vierers ~ Ni. Westie Plane diagonal. Wits : : ae Plane horizontal. D»*. Period over 2, Dihedral. Dn. Dihedral....) ane di agonal. Dp? 4. Several axes of period over 2. Period 2, Tetrahedral. T Tetrahedral Jpme linen, te ) Ry a ** | Plane diagonal. lth Period 4, Octahedral. O. Octahedral .. Plane horizontal. O+., These divisions develop thirty-two groups of symmetry by changes in the periods of the axes. % Leipzig, 1891. See an excellent brief synopsis of his results in G. H. Williams’ Crystallography, third edition, 1892, pp. 183-195. 40 Ibid., p. 129. 41 Tpid., pp. 74, 102. 394 ‘C.K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS Schoenflies proposes a two-fold classification of the thirty-two groups so developed :*? I. Into divisions based on the period and character of the principal axis of symmetry comprising Isometric, Hexagonal, Tetragonal, Trigonal, Digonal, and Monogonal divisions. II. Into the ordinarily accepted seven systems, essentially as in the classification of Gadolin. His work, which is of great importance, closes with a highly suggestive discussion of the inner structure of crystals. Mvers.—It remains to make reference to the classification introduced by H. A. Miers in the year 1902 in his work on Mineralogy.** He recog- nizes the close relations which exist among a number of the groups of crystals, giving them analogous names. He classifies a large number of the groups into the four divisions recognized by Hessel and designates them in a somewhat analogous manner, prefixing the syllable di (dou- ble = Hessel’s zweifach) to the name of the system for groups having crystal faces in pairs. He does not, however, apply the same classifica- tion to all systems of crystals. His divisions are exhibited in the follow- ing table,** in which the larger grouping is numbered and arranged by the writer. Miers does not present the larger grouping here given. I. No axis of symmetry. | 1. Asymmetric. 2. Center of symmetry. 3. Plane of symmetry. II. Possessing a principal axis of symmetry. . 5 In . 1. Polar (hemimorphic) Var can (di). 2 Alternating | Bape an 3. Holoaxial (many axes) { Single. Single. 4. Equatorial (horizontal plane of symmetry ) Double (di). III. With equal axes (Isometric). Single. Double (di). 2. Holoaxial (many axes, four-fold) { Single. Single. Double (di). RELATION OF THE DIVISIONS PROPOSED TO THOSE OF PRECEDING AUTHORS 1. Polar (hemimorphic three-fold axes) i 3. Central (center of symmetry ) { The relation of the author’s results to those obtained by the various investigators is shown in the following tables, the first giving the larger divisions and the second the subordinate groups as developed by the dif- ferent authors: | 44 Tbid., pp. 110, 125-131. 48 Mineralogy. MacMillan and Company, 1902. “ Thid., p. 280. ' 395 RELATION OF THE DIVISIONS -OWO "[BIxeqa -UW ‘SIXv SUIQVUIO}V ‘2 “UO1JIOPoL pue UOI1}BIJOI pouIquIOD “]TT ‘[Bapoyeqow vy "souvl[d suyvusoy “9 ‘[BApoyouy -I1Q) ‘souvld suIPlUIO() *G —YJIM soxe AuvyT “G ‘[eIpep, ‘ouvyd jor[eaegd ‘F "[BIXR ‘ouvyd [BullonN “e —Y}IM SIX¥ 9UQ “VW ‘uooopea Aq AtgouuIAG “TT ‘[erxvdAjOg ‘soxv Auvy °Z ‘[VIXV ‘SIX¥ 9UQ ‘T “uoTyeyou Aq AayouUIAG *T B06 ‘Z4BA\G ‘SUIIOZ (OTQNOp ) «ID,, PITA [erxvojoy O9ABVS SUOISIAIPGNS [[V ‘(Argouuu As JO JoyUa.) [BIQUED °¢E ‘[BIXBVO[OH] *% “Av[Od ‘T *(OLMour -OSJT) soxe [Tvuby ‘(ouvyd [eyu0z elit: -10y) yewoyenby ‘F *(SOxR AuvUL) [eIxBojOy °¢ ‘OYVUIITV °Z (orgd -LOUIMOY ) TBLOg ‘T ‘SIxe [vdiulg ‘]] “AIZOULUTAS JO SOXVON “| ZOBL ‘SHOT, ‘sdnoas sutpuodset100 SUIp[OLA Sox” SuTpooeId ysnoryy possed oe sour, g "SOX PUB SOUB[ “[] ‘(OLIJOULOST ) OMY uvYy} e10UL port -od JO SOXB [BIDAIQ *F ‘jedroutsd QUO—SOXB [VIDADG *C ‘SIXB OUQ Z “AYJUOPT “T “A[UO SOXYW “J I68T ‘Serpusoyog ‘S]UBUIUTIE}Ep jo suvowut Aq podojoaog “PLOF ouO 10 OMY ‘polseg ‘€ "ploy Anoj ‘potlog °Z “PlOF 901} JO XIS ‘polwog "| Tetpeyld ‘IT ‘(OL -JOULOST) [VIPEYRVO ‘| J881 ‘oporostuUulyy *(OLTJOUr -OST) Soxv [enbe yIWA\ “TT “PIG auo 10 OMY “pollag “§ “PlOJ ANoF ‘potsd °Z : "PIF so1Y} IO XIS ‘poed ‘T ‘SIxe [ediourrd YIM “T G88] ‘Mo10po,y ‘AajourutAs Jo souryd jo uonisod pur souesoid uodn posvq suorstArpqng ‘(SIX¥ ou ‘ST quy}) UoTyIgedet ON “XT ‘(SIXB 9UO ‘SI qvy}) SIXB OSTOAUT “TA ‘(sox Auvut ‘st 4vq]}) Ssoxv [ediourd ofqnog ‘A ‘[eIpseyeyaL “AT CHG) JOU FS8T ‘olny “ATJOUTULAS ([VpPIOU -oyds) sueudoipTy “¢ ‘joy[ervd you soovy °Z ‘[ayjeuvd soovy TL ‘SOXV pu SOUR[G “TI ‘SIXU ON ‘€ ‘SIX¥ OUQ °Z ‘soxv AUR], “T ‘A]UO SOXYV ‘J 1Z8T “UlTOpeRy "OMY uvyy sour poll -od JO SOX [RIDADG “TIT 19}U90 PUB SIXW 0 "SOXB OMT, “9 ‘souv[d OM], 9 “ATQOUI -WAS JO SOSBG OMT, °Z “AJUO STXB OU) “T ‘SIxe [vdioutad WIAA “TI ‘AOU -wiAS JO STXB JNOYIA “T (9881) Test ‘Smiqooy, "SOXU ploj-90143 INOW ‘T "AY -oulw As [eproreydg *A JT PD POERe Oda ‘Ud9AD POLlog ‘| ‘Stxe [edrourid ‘ajqnop pur o[duIs 1B 4SB] OARS [lv Josoxe jedpud oy, (2) onbijqo sumo *9 (6) ojvus09}][B SUIIOT “9 (9) ay1soddo sum10,q “9 “pepuo 8yIT[ SOXYV °% YU oTayourm Ag “]]TT |) popucoylun sixy “T ‘stxe [edroursd qNOY PA oAyouIUIAG “TT ‘OItjouIUI ASW "T 6FST ‘SBIABIg ‘stxv jedroutd v YA “TT ‘(OLLJOUIOST) STXB jediourd vB ynoyyTA ‘T OS8I ‘TesseH, spppshuy fo suo sabivT—] WIA, OF CRYSTALS PROPOSED CLASSIFICATION Cc. K. SWARTZ 396 SIXB 18] “8 ULS ON SIXB AB] NSUIS sees. eeeeee bees eeresess | seeeewessee Pe eeee ees eesl|aseeescoes se eeee esses | seeerenenons se ee ee deeees| seeeeeseenes cee eee sewer see eeseeeees peecee tesco | tetees sees ee eeeerennes eeeeee [VlpoyVqeuly ye? ely 99 OLLI Cael (OA TAN (1) ao ST Vesa 98 TL C@ I GEITA eT] 6] 2 11 aS 1S: rel iSiexel Too oe ‘Oo (ay WI 19 11 64° 8a" BE OE Pel ae O dh S11 GIT 1¥¢ ‘II | ae ‘II eye fp Sn AN al it oT] 'H='O ab aN | AAN 29 1V eX TP p z ae" ie ie or" ie a? 92° FL" ne I yee “YAOI oe alee te alee Sully | OTIS | erie) Sec ee TT | Og ET |My gig’ eine Ae oTae || SCR eG errr ae eee IN tee eeeeeeses|eeeereeeenee aw 1O %Qq bad ®q] uA %O Pag G9 ae) g soso SorTpuUsoyos reece eceser| sores secees PIT ley 91 I 8L'2zI yee at 67°27 Der It 61'Z I PIL T 9Z'¢ T OS ST “9 polos lUUl [Al oe el eee nee see ielet Lala ie Wee i | Thule eboney o/ROMit onl UIT RGne aie eueGeleem| anes reo gaol ee ete alates wales ORNL GIIL | 962 VZA £36 A GEA C2 UA TPA eae JUN eri ION 4 SE IP EO) gt) eee lot ae Oe Meee aeD se Ga reNslen mcecuiilme eC TUTE leueclel lect | CO ceuktem ates eariilien (Gaeta eee setae tears Uy cra) Peewee eerens| seeseeeseees oH & see eer a) ae, 9V by 8y by “oy seeereees “BNIQOOIN SE OE IEE TE Se CU EO eT PaO eae OE) ah pee chee ena Seececvcces| cosececcvcos AG iF es 3} 9) ZL pe aL ex z 5) aL ma) al pu 3 mn aL a 5 0 al OD USEC estoy | v G 9 V § G 9 v € G I “SOoxe JO polled SIX’ Tel AGeniale IV[NSUIS ON SIXB Iv]NSUTG [BIPSYOULO [B.ipo fT Va" GL BL 3 95 GG Giles (NI ¢° a" OL io) ¢ te “TIO. Peeae Gor pone Pot Mean Pea ese Pea eee elise IP Betine chia aa ‘SLOT IAL °q al *q A atte) aire) a) are) Be 149) 19) Ki WK je sorgueoyos ‘Sie eal Oko GAP SEV 16° J (Sri Il 16G | @IE IL MN cxgrce IE || OEM I} era JAE |) Rae At Zee] jv eposos uur yy SLT ICS Petts AGES Sy Me Ge A SONI Te EAST IESE Moka TI ee ST ASTRO ee Cewek sygi SG) AN PLA tay Th AN GLA Ne TUN | GIN Eto WAN tae TE SIN LGA | EIU PaO HP UE cae Pee itada ys) le See Be eae i SS Pelle 8 olk SI Per ead Rec earache Sheen eine eeesame Uns len) 9g Vg Soi See MAL via i dl H YI 8 ai eee SOG SON S000 Aue pyc) nee | eedae Pvemdae |e) “ear ne | acne | Moe ae ede Pee eee speci) 9? tL pol | yt ull 29 iL oo iL | +0 tL a) WE 9) we i} al at p0 iL 0 iL au iL TORT es eee see BOT 9) ay g U6 9 17 ¢ v6 9. a7 g ve I “SOX®B JO poltod SIX "SUIS ON SIXB’ IBpnsurg [VLXBVqouly [VIXBA[Og [VIXVOTILO [RIX Y- sppjyshayy fo sdno“4j—J{ XIAV, SUMMARY 397 Notes on Table II.* Unless otherwise stated, the formulze preceding the period (.) indicate the divisions given in the foregoing discussion, which are summarized in table I. The number following the period shows the author’s number of the group. Letters are used when the author has so employed them. § indicates section in which the group is discussed. Hessel.—The letters indicate character of chief axis; for example, u = un- gleichendig, etcetera. The large number shows number of such axes; the first small number indicates whether axis is single (1) or double (2); the second small number shows period of the axis. This 1?G? signifies one double axis. gleichstellig, 2-fold.* Miers.—Letter signifies division; for example, p=—polar; a —alternate, etcetera. Small figure 2 signifies double (di) form. Groth.—Numbers indicate group. Physikalische Krystallographie, 4th edi- tion, 1895, pp. 329-331. SUMMARY The purpose of the preceding discussion is to point out the existence of certain natural and well defined types of symmetry in crystals, and to present a development of the thirty-two groups which is adapted to the use of elementary students and which emphasizes simple and natural relations of crystals springing from the existence of these types. The subject is treated in two parts. Part I contains the discussion of the classification proposed by the author. 1. An elementary development of the thirty-two groups is given, by which it is shown that all crystals fall into seven fundamental classes of symmetry. 2. The seven classes are named, the characteristics of each are dis- cussed, and the term class defined. 3. The various classes and groups are referred to the accepted systems. 4. It is shown that this development expresses the larger relations and harmonizes with the fundamental physical properties of crystals. This table is based in part on a similar table of Schoenflies, “Krystall Systeme und Krystall Structur,’’ 1901, table iii, p. 104. 46'These formulze were first used by Hessel in a later publication, ‘“‘Ueber gewisse merkwiirdige statische und mechanische Higenschaften des Raumes,”’ Marburg, 1862. Universititsschrift. 398 C. K. SWARTZ—PROPOSED CLASSIFICATION OF CRYSTALS 5. Certain inferences springing from the preceding discussion are con- sidered. 6. The advantages which are believed to be presented by this method of development are briefly summarized. Part II contains a brief historical review of the development of the modern classification of crystals and shows the relation of the author’s — divisions to those of previous investigators. é Jett KA a aont a u | fg i \. & tease JAMAOK 2¥AI4 } SAT AVS OM oe wa A TRAM « " . U + JAIM AGAMA ix a pests KNSTIA : -“ Leis | we Cre" Syl Af Q3H av 7“) J eds site 5 aoraesme eaUUs ee ae PY RPI NAS, pt ss ik aa ao ae tie ca al | i i , ‘ { j ' } as - " ane anont ao az ; st a Ls aon et ly ‘ ‘ t i } ‘ 4 td BULL. GEOL. SOC. AM. Hasek “D: OAe SINGLE roan 3 SINGULAR DIR TRICLINIC | MONOCLINIC Gao A aa sr VES 1-2 FOLD 1-2 FOLD dike \ Zo I . / \ F { A X | A L 1 ee. an t ai- | * be ave het ONE AXIS A \ | fi x I r peers ‘<2 ee ASYMMETRIC PYRAMIDAL HEMIMORE ORTHOAXIAL = PLANE NORMAL TO AXIS LJ c r—) PYRAMIDAL => mis| POLYAXIAL = = = MANY AXES [oa cS ra = AMEBAXIAL |e ALTERNATING AXIS onal l= = ‘ ro HEDRAL (a = Te) PLANES INTERSECTING IN ONE AXIS ‘ =| ORTHOHEDRAL rw = PLANES COINCIDING WITH AXES Li = as = Tus SIE AMEBAHEDRAL fe PLANES ALTERNATING WITH AXES == = CLASS VOL. 20, 1908, PL. 31 i | SINGULAR DIRECTION NO SINGULAR DIRECTIONS | RHOMBIC) TRIGONAL | TETRAGONAL | HEXAGONAL ISOMETRIC ) FOLD 4 FOLD TRIPYRAMIDAL TRIPYRAMIDAL TRIPYRAMIDAL HEMIMORPHIC HEMIMORPHIC HEMIMORPHIC = ae I | | ! ] ay | | | | me! Le a TETARTOHEDRAL PENTAGONAL HENOIDAL TRAPEZOHEDRAL _TRAPEZOKEDRAL PENTAGONAL DODEAHEDRON| __ \COSITETRAHEDRAL 7 DIPYRAMIDAL DIPYRAMIDAL DIPYRAMIDAL DAL HEMIMORPHIC HEMIMORPHIC HEMIMORPHIC HEMIMORPHIC PYRAMIDAL ‘DIPYRAMIDAL DIPYRAMIDAL DIPYRAMIDAL HEX TETRANEORAL SCALENOHEDRAL 1 SCALENQHEDRAL YSTALS BULL, GEOL. SOG. AM. : , VOL 20, 1908, PL. 31 NO SINGULAR DIRECTIONS —— SINGULAR DIRECTION 3_SINCULAR DiREGTS TRICLINIC TETRAGONAL 4 FOLD HEXAGONAL 6 FOLD TRICONAL 3 FOLD, WRU AT Sessa ISOMETRIC 12 FOL 4 FoLo AXIAL ONE AXIS | IAMIDAL TRIPYRAMIDAL TUNInanenic HEMIMORPHIC TRIPYRAMIDAL AsrMMeTRiC | py HEHIMORPHIC ORTHOAXIAL —— was PLANE NORMAL TO AXIS S es] co a TRIPYRAMIDAL TAIPYRAMIDAL HYRAMIDAL = BF FYRAMIOAL uu [ray > ==! mi] POLYAXKIAL I ==> eles Es =|s|\o MANY AX ; ui = ; 3 e : = pe ne TETARTOHEDRAL natn A pHeNDOAL TRAPEZONEDRAL U2Ad 2 LN) EN FRAPEZONEORAL _ [pENTAGONAL DODLAHEDRO} ICOSTETRATEORAL = =| AMEBAXIAL = = ALTERNATING AXIS = = PYRAMIDAL TRIRHOMBONEDRAL a | HEDRAL PLANES INTERSECTING IN ONE AXIS SINGLE DIPYRAMIDAL DIPYRAMIDAL PYRAMIDAL HEMIMORPHIC] __NEMIMORPHIC HEMINORPHIC HEMIMORPHIC ORTHOHEDRAL PLANES COINCDING WITH AXES PYRAMIDAL DIFYRAMIDAL DIPYRAMIDAL DIPYRAMIDAL DIPLOIDAL HEXOCTANCORAL a ae AME BAHEDRAL PLANES ALTERNATING WITH AXES 1 1 1 Soe ye - oan [Ses SCALENOHEORAL SCALCNOHEORAL HEXTETRAHEORAL CLASSES OF CRYSTALS ~~ = 4 i a} i ee : 2 a a a i Vee aS. ee pe! i: EE CN Ma Iie " . ee a | 1 . a —_ | —- ee _ Sa" eee eee ‘3 i s | sie | a 5 ow 28 qo 3 he . 5 oy + . é 4 2M; ee: AS Pood { - - ht es i ‘J > y el = etl Me a Steve we, » hat ae | gett “np Soot, PAIX AR IMA 4 “agp joni ranenera pare br aN ph eminent ee MR v= BULL. GEOL. SOC. AM. DO ReA L ALTERNATE ~ DIRECT E H 8 SINGULAR DIR TRICLINIG | MONOGLINI 1-2 FOLD 1-2 FOLD, ONE AXIS CL aos Sor Ss ex ORTHOAXIAL PLANE NORMAL TO AXIS PYRAMIDAL POLYAXGAL MANSY VAUX SECS AMEBAXIAL ALTERNATING AXES DOUBLE : : ALTERNATE OBLIQUE DIRECT SINGLE HEDRAL PLANES INTERSECTING IN ONE AXIS ORTHOHEDRAL PLANES COINCIDING WITH AXES L = AMEBAHEDRAL PLANES ALTERNATING WITH AXES CLASSE VOL. 20, 1908, PL. 32 T SINGULAR DIRECTION NO SINGULAR DIRECTIONS ‘RHOMBIC TRIGONAL | TETRAGONAL | HEXAGONAL ISOMETRIC | FOLD U 1 1 1 ‘ i) TRIPYRAMIDAL TRIPYRAMIDAL TRIPYRAMIDAL HEMIMORPHIC HEMINGORPHIC HEMIMORPHIC By Se eee 53 wots =e PENTAGCNAL HENOIDAL ICOSITETRAHEDRAL TRIRHOMBOHEDRAL N BIPYRAMIDAL HEMIMORPHIC DIPYRAMIDAL HEMIMORPHIC DIPYRAMIDAL A). HEMIMORPHIC HEMILMORPHIC YRAMIDAL DIPYRAMIDAL DIPLOIDAL HEXOCTAHEDRAL STALS BULL. GEOL. SOC. AM. Cl AS SEs 8 SINGULAR DIRECTIONS TRICLINIG | MoNocuyig anno) TRUCONAL | TETRAGONAL |” HEXAGONAL 12 FOLD, hess AXIAL ONE AXIS ORTHOAXIAL PLANE NORMAL 10 AXIS ed — ju als POLYAXGAL > le MANY AXES lo lS x i—} ALTERNATE AMEBAXIAL ALTERNATING AXES PYRANIDAL HEA IMOR He EO RA SINGLE DIRECT ALTERNATE HEDRAL _ PLANES INTERSECTING IN ONE AXIS ORTHOHEDRAL PLANES COINCIDING WITH AXES AMEBAHEDRAL PLANES ALTERNATING WITH AXES “AN 11D VOL. 20, 1908, PL. a2 J 1 SINGULAR DIRECTION NO SINGULAR DIRECTIONS ISOMETRIC 3 FOLD 4 FOLD 6 FOLD 2 FOLD 4+ FOLD ruin | tries | mona TRIPYRAMIDAL TRIPYRAMIDAL TAIPYRAMLDAL TRAPEZOEURAL TRAPEZOREDAAL RAS ee TRISPHENOIDAL TRIRHOMBOMEDRAL i DIPYRAMDDAL DIPYRAMIDAL DIPYRAMIDAL | HEMMORPHT HEMIMORPHIC HEMIMORPHIC DIPYRAMIDAL DIPLOWDAL HEXOCTAHEDRAL SCALENONEDRAL SCALENOHEDRAL HWEYTETRAHEDRAL CLASSES OF CAYSTALS So. 19 aaa oe ide fet sate ot eemamaies paaepmenacne rr _— | oe a a ar Ie mes re im) = | j j * “ . } an es > ; .. € i f / wr Circ } ; ‘ q : ‘ ; ; ee See : | ! | ' : : " . ; i | A | (i ; t ’ J : : é ' J SeFLS- i - H Mars. «t..- { i : ' ; H y 4 } } abel ; ; ; s2i MR ity ee er < : exahirin scunslarger ; Rey a Tovah ot pees 2. “ tT mae a ‘- ; - . o- | | : : . . | . | rrp fan ee fete . A} ‘ x yf : as LI be, iyi a ; Y Sei pha j # - ay, - ie - . : ASOINETH Ar? r ; [__ seseneharn bate jemvaarese] es ae LAROCHE EET Q : ‘ ed LTE MANNA No NRO ee | | | eT ee ae ‘ . . - : ij = — f . ares ae | i i ae he ar ; : ‘i l lk, . >} \ j . * em "i - s "a ri i ~ ty Pa { os i 4 i ’ _ $f. ' \ bz = ' \ r Va : ‘ fe . i f ™ Ff i : : ) 4 7 . : ; . me ‘ | 3 t ) “/ }. et eee, ee 4 rie 4 ams pe H ; ; i; : : 41M 55 a0 ; Tee a: ely sas RR ee Ae ee BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 399-408, PLS. 33-37 DECEMBER 24, 1909 AFTONIAN SANDS AND GRAVELS IN WESTERN IOWA? BY B. SHIMEK (Presented by title before the Society December 31, 1908) CONTENTS Dawe MMPI ND EL ELCOTIMMB AN ay og ete lds cate, ah aoa) A eter hd ve ele Pee Boe. hal aetaine eee lebanese AINE Maes eee Ta 399 Previously known distribution of Aftonian beds in Iowa.................- 399 eta TT Bout Mh oP ee Towle wa cnin Bd Por aia oA abey sarin Le Se UR UDR TST Sie ate ele! ote me ac lenges 399 paeed NOL MR totL CREAT SEL I Nened a civense tatiafin Ve iuhsniey aa vci onstrate: outset eulapheycy Si ee S etaunt alee Beet aaa ues arepat 400 new mOmlDmaml WeESterm TOW. os. i... oo nee cca ane Uhascceue muse calewe see 400 Panam Sms Keni “WESTOLIN: LOW. cea cc. toile ole «ous & Sie epee Pelee ss ele walendiere « are 400 E esteuulnnte ter IDEM Sis, 2). oe a taievere o2ec. «0 SdlS al cud mies!» Mins. .¢ 6e one Siar ar Signa! ators une ers 401 Cee SnCOncamine MAMMAM AN! LOSSIIGG 0 oe ce cis file leven eens ade dc 401 Sands) bearing molluscan fossils..............-. coi Ge NCATR PE oth eve deat 402 Seiten SSM anG: “avltitUGe: Ol DEUS: . scutes a\5d.6 cue ess coats. o/c) nie le ei sire «: evetencss! love 403 Misiabupion in Harrison and Monona coumties.............0ceenc cee 404 Danenceswucn the bedsvare Aftonian.. 2.0.05. .005 06 Ob ok ele ees oe 404 ae nana) LEC ETO SULTON is ets tain hie Eid eet gtyater adele Casale abe cine itis artes from Cedar county (doubtfully) ;° from Tama county;’ from Chickasaw county ;° from Union county,® and several additional probable localities in south- ern Iowa are given by Bain.*° Four species of mosses (Hypnum)*™ and the wood of a conifer (Larix)? have been reported from these peat beds. SAND AND GRAVEL Gravel and sand beds belonging to this stage have also been noted in the Reports of the Iowa Geological Survey from the following counties: Marshall,!3 Muscatine,!4 Louisa,!® Webster,1® Benton!” Ida and Sac,!* and in other publications from the type locality in Union county. It will be observed that thus far no gravels from the western part of the state have been definitely referred to the Aftonian. THE AFTONIAN IN WESTERN IOWA While engaged in the survey of Harrison and Monona counties for the Iowa Geological Survey the writer found numerous deposits of sands and eravels clearly belonging to the Aftomian stage.?° At a number of points in these and neighboring counties sand and gravel pits have been operated for several years in connection with cement block and tile plants, or for building purposes, but the deposits were regarded as local pockets. PREvIoUS WORK IN WESTERN IOWA The geologists who have studied the neighboring counties in recent years found like deposits of sand and gravel, and regarded them as lacus- *By Finch, Beyer, Macbride, and Calvin, in Proceedings of the Iowa Academy of Sci- ences, vol. iv, 1897, pp. 54-68; T. E. Savage: Reports of the Iowa Geological Survey, VOleexVvenl OOS saps 2o- 5 By W. H. Norton, ibid., vol. ix, 1897, p. 474. S By W. Hi. Norton, ibid., vol. xi, 1899, p. 343. 7 By T. EH. Savage, ibid., vol. xiii, 1903, pp. 232-233. 8 By S. Calvin, ibid., vol. xiii, 1903, p. 291. °T. C. Chamberlin, in the criginal references cited; T. E. Savage: Proceedings of the Iowa Academy of Sciences, vol. xi, 1904, pp. 103-109; S. Calvin: Proceedings of the Javenport Academy of Sciences, vol. x, 1905, p. 19. 10H. F. Bain: Proceedings of the Iowa Academy of Sciences, vol. v, 1898, pp. 98-99. uj. W. Holzinger and G. N. Best: Bryologist, November number, 1903; T. E. Savage: Proceedings of the Iowa Academy of Sciences, vol. xi, 19804, pp. 105 and 108. 2T. H. Macbride: Proc. of the Iowa Academy of Sciences, vol. iv, 1897, pp. 63-66. 12S. W. Beyer: Vol. vii, 1897, pp. 231-232. 14 J, A. Udden: Vol. ix, 1899, pp. 338-3389. 15 J. A. Udden: Vol. xi, 1901, p. 1p4. 6/ 16. A. Wilder: Vol. xii, 1902, pp. 130-131. 177T, EH. Savage: Vol. xv, 1905, p. 202. 18T, H. Macbride: Vol. xvi, 1906, p. 532. 12H. KF. Bain: Proceedings of the Iowa Academy of Sciences, vol. v, 1898, pp. 86-101; S. Calvin: Proceedings of the Davenport Academy of Sciences, vol. x, 1905, pp. 18-30. 20 The writer published a note concerning them in Science, Dec. 25, 1908, p. 923. BULL. GEOL. SOC. AM. VOLE. 20, 1908, PE-{33 FIGURE 1..—JLOOKING ALMOST DUE HAST (a) Kansan; (0b) contact line, weathered and with calcareous plates; (c) Aftonian sand, 21 feet; (d) fossiliferous Aftonian gravel, 10 feet exposed FIGURE 2.—LOOKING SOUTHEAST (a) Kansan, 13 feet; (b) contact line; (c) sand, 21 feet; (d) gravel, 14 feet exposed COX PIT, EAST OF MISSOURI VALLEY, IOWA PREVIOUS WORK IN WESTERN IOWA AO1 trine”! or fluviatile,?? and as modified drift, referring to them as “stratified drift,”?* “eravelly drift,’?* etcetera, but no effort was made to fix their stratigraphic relations.2? Udden?® evidently included them in the till, or at least considered them of glacial origin.*’ The gravel beds of Harrison and Monona counties have heretofore re- ceived but little attention from geologists. Saint John considered them “modified drift,’?* and Bain found “gravelly drift” in the northern part of Monona county ;?° but here also no attempt was made to definitely determine either their geologic horizon or their extent, for Saint John’s observations were made in connection with a preliminary survey of that part of the state long before the modern differentiation of glacial and interglacial deposits was recognized, and Bain’s studies in these counties were made incidentally, in connection with the survey of an adjoining county, and were restricted to one locality. ‘The recent investigations, however, show not only that these sands’and gravels occur in widespread beds, but that they are unquestionably Aftonian. DESCRIPTION OF THE BEDS GRAVELS CONTAINING MAMMALIAN FOSSILS The beds consist of interbedded and cross-bedded gravels and sands, as illustrated in plate 33, figures 1 and 2. The gravel is water-worn and variable in coarseness, sometimes con- taining small boulders up to 4 inches in diameter, and consists largely of foreign materials such as might be from the drift, and with occasional fragments of fossiliferous limestones, evidently of far northwestern origin. Occasionally large boulders, chiefly of Sioux quartzite, are also found. The beds are often strongly iron-stained, as in the exposure shown in plate 34, figure 2, the iron sometimes cementing the gravel into plates and masses of conglomerate, and occasional bands and wedges are almost black with MnO,. They also contain small “boulders” of light bluish gray silt or dark blue black sub-Aftonian till, densely covered with sand and fusiform or spherical in form, as if shaped by rolling on the bottom of a stream. 21H. HF. Bain: Reports of the Iowa Geological Survey, vol. v, 1896, p. 277; J. A. Udden : Ibid., vol. xi, 1901. 22 J. A. Udden: Ibid., vol. xi, 1901, p. 255, and vol. xiii, 1903, p. 166. eH. F. Bain: Ibid., vol. vill, 1898, p. 338. 244A. EF. Bain: Ibid., vol. v, 1896, p. 281. 2 Hixcept that Macbride referred the gravel beds of Ida and Sac counties, in the same section of the state, to the Aftonian in general terms. Ibid., vol. xvi, 1906, p. 532, ete. 26 Towa Geological Survey, vol. xi, 1901, p. 251, ete. 27 Tpid., p. 254. 28 White’s Report of the Iowa Geological Survey, vol. ii, 1870, pp. 177-184. 2) Reports of the Iowa Geological Survey, vol. v, 1896, p. 281. 402 B. SHIMEK—AFTONIAN SANDS AND GRAVELS IN IOWA In these gravels were found numerous remains of extinct mammals belonging to the genera Hlephas, Mamut, Equus, etcetera, which are dis- cussed more fully in Professor Calvin’s paper. They were especially abundant in the typical exposure shown in plate 33, and in the Peyton pit at Pisgah. These remains consist of bones, teeth, and tusks, and are more or less fragmentary and promiscuously distributed through the coarser parts of the beds, having evidently been transported and scattered by the same strong currents which moved the gravels. A vertebra of a small fish was also collected from finer gravel. A few heavy-shelled Unios were found, but they are more or less fragmentary, the shells being chalky and very fragile. Only one species, Quadrula metanevra Raf., could be positively identified. ‘The species is now com- mon in the rivers tributary to the Missouri. Unidentifiable fragments of at least two other species are in the collection. The abundance and wide distribution of the bones and teeth in these eravels and their comparatively good state of preservation suggest that they were not derived from older formations or carried long distances, but that the animals lived and died in comparatively close proximity to the present burial ground of their remains. SANDS BEARING MOLLUSCAN FOSSILS The sand beds are stratified, and sometimes interbedded and cross- bedded with finer gravel, and quite variable in fineness. They also vary in color, some being rusty red with iron, others almost black with MnO,, and in the lower part of the deposit, beds of almost pure white sand often occur. They usually contain small, very soft white calcareous nodules. The finer sand is sometimes cemented into plates and blocks which usually grade into loose sand below. These blocks are sometimes so mas- sive that they have the appearance of bedded rock, as in the exposure on the east side of the Little Sioux river, near the north line of Harrison county, and at Loveland and near Council Bluffs, in Pottawattamie county, south of the Harrison county line. A little of this is shown near the middle of the lower part of plate 37, figure 2. These finer sands contain numerous shells of fresh water and land mollusks, all belonging to modern species, which are scattered through the sand in much the same manner in which more recent shells are scat- tered through the sand of modern river-bars. The shells are exceedingly fragile and are difficult to handle, but a sufficiently perfect series was collected to determine the identity of the forms with species now living in the same region. ‘The following species have been thus far identified : BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 34 FIGURE 1.—LOWER PART NEAR SOUTH FIND (a) Sub-Aftonian; (b) weathered band of (a); (c) Aftonian FIGURE 2.—UPPER PART NEAR NorrH END (a) Kansan; (0) Aftonian; (c) talus, COUNTY-LINE EXPOSURES OF AFTONIAN, SECTION 5, TOWNSHIP 81 NORTH, RANGE 44 WEST BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 35 FIGURE 1. EXPOSURE IN SERTION 7, TOWNSHIP 85 NorTH, RANGE 44 WEST (aw) Kansan; (b) contact line, weathered and with calcareous plates; (c) Aftonian sand EIGURE 2. EXPOSURE EAST OF LOGAN, IOWA (a) Missourian limestone, 4 feet; (b) Aftonian gravel, 2 feet; (c) Aftonian sand, 10 feet; (d) Kansan joint clay (Loveland), 7 feet; (e) loess, 15 feet SECTIONS SHOWING POSITION OF AFTONIAN DESCRIPTION OF THE BEDS 405 Aquatic Species Sphaerium suleatum (Lam.) Prime Segmentina armigera(Say)H. & A. Adams Pisidium sp.? Planorbis bicarinatus Say Valwata tricarinata Say Planorbis parvus Say Valvata bicarinata Lea Lymnea caperata Say (7) Fragments Ancylus rivularis Say Physa sp. ? Fragment Terrestrial Species Vitrea hammonis (Strom.) Pils. Pyramidula striatella (Anth.) buts. Zonitoides arboreus (Say) Pils. Pyramidula alternata (Say) Pils. Vallonia gracilicosta Reinh. Succinea obliqua Say Bifidaria armifera (Say) Sterki Succinea avara Say The aquatic species belonging to the genera Spherium, Pisidiwm, and Ancylus are most common and most widely distributed in the beds of finer sand. All the aquatic species in the list are now found living in the same region in the streams tributary to the Missouri, and in adjoining ponds. The fossil land shells are more local in distribution and fewer in num- ber, only scattered individuals being found. ‘The species are all repre- sented in the modern fauna of the same region. It may be worthy of note that while all the species of land shells here listed are also found in the loess, they are there never mingled with fresh- water shells in the same manner.*® On the other hand, such mingling of fresh water and land shells as is here recorded is common in all the modern alluvial deposits of the same region. The presence of these shells, then, shows that fluviatile conditions prevailed in the immediate area con- cerned, but that land surfaces on which the terrestrial mollusks flour- ished, and from which they were washed by floods, were near by. No uniformity marks the relative arrangement of the sands and gravels. Sometimes the finer sands form the uppermost member of the series, as shown in plate 33, figures 1 and 2, and plate 35, figure 1; again, the heavy gravels occupy this position, as in the county line exposure shown in plate 34, figure 2, or the sands and gravels are indiscriminately interbedded. ‘These differences simply indicate variations in the force of the ancient currents. THICKNESS AND ALTITUDE OF BEDS Where undisturbed, the sands and gravels are usually very clean, espe- cially along the tributary valleys, but in the main bluffs of the Missouri valley they are not infrequently mingled and interbedded with silt. %0 Freshwater shells are exceedingly rare in the loess, and are almost exclusively Pul- monates, and such genera as Spherium, Ancylus, etcetera, are unknown. 404 B. SHIMEK—AFTONIAN SANDS AND GRAVELS IN IOWA They vary in total thickness up to 40 feet, and rise to a height of 10 to 40 feet above the latest alluvial plain. But where they have been plowed and crowded by the overlying Kansan they are frequently mingled with joint clay, till, etcetera, and are often piled up to a greater height, as in Murray hill, northeast of Little Sioux, where they rise irregularly to a height of more than 100 feet above the general level of the valley. DISTRIBUTION IN HARRISON AND MONONA COUNTIES In the two counties under consideration the Aftonian beds are distrib- uted along the bluffs bordering the Missouri valley,** and along all the principal tributaries—the Boyer, Soldier, Maple, and Little Sioux rivers. Sometimes they are present on one side of the valley, and again on the other. Thus along the Boyer, below Woodbine, they appear on the west side of the river, while in the lower course of the same valley they are on the east side. More rarely they appear on both sides, as along the Maple river, near Mapleton. This is consistent with the distribution of sand and gravel bars along modern streams. EVIDENCE THAT THE BEDS ARE AFTONIAN STRATIGRAPHIC POSITION That these sand and gravel beds are Aftonian is clearly shown by their stratigraphic position between the Kansan and sub-Aftonian drifts. This is well illustrated in the county line exposure near Little Sioux, the first exposure in which the writer definitely determined the stratigraphic posi- tion of these deposits, where a great bed of sands and gravels, not less than 15 feet in thickness, lies between the sub-Aftonian till exposed at the base of the bluff and the typical Kansan till above, both of which it meets un- conformably.*? Both sub-Aftonian and Kansan, with the intervening Aftonian, are exposed at a number of points in this region. Such exposures were found in Monona county, in Woodward’s glen, in section 17, township 84 north, range 44 west, and in a well near Castana, in section 13, township 84 north, range 44 west; in Harrison county, in section 5, township 81 north, range 44 west (the county line exposure already noted), and on Murray hill near the corner of sections 7, 8, 17, and 18, in the same township, and in the bluff above Loveland, in Pottawattamie county.* 21 Sand and gravel beds at several points on the west side of the river, in Nebraska, are also Aftonian. 32 For the contact line in this exposure with the sub-Aftonian, see plate 34, figure 1; with the Kansan, plate 33, figure 2. * More recently the writer discovered several additional similar exposures on both the Iowa and Nebraska sides of the Missouri. EVIDENCE THAT THE BEDS ARE AFTONIAN 405 In many other cases the sub-Aftonian is not in sight, but the overlying Kansan is clearly shown. This is well illustrated in the Cox pit, near Missouri Valley,*? and in a pit near Grant Center, in section 7, township 85 north, range 44 west,°* but the same relation is shown clearly in nearly all the exposures studied in Harrison and Monona counties. Even in the few cases in which the Aftonian is not in contact with the sub-Aftonian or the Kansan, the position of the beds is stratigraphically consistent. Thus at Logan the bed of gravel 2 feet in thickness, with overlying sands 10 feet in thickness, hes directly on the Missourian lime- stone, no sub-Aftonian being present.*? Resting on the sand is a bed of reddish joint clay,*® and above this is fossiliferous loess. While there is: no Kansan till in this section, the presence of the Loveland makes the position of the Aftonian beds consistent. At Denison, in Crawford county, a bed of cross-bedded sand and gravel 35 feet in thickness lies immediately below a bed of fossiliferous loess, evidently post-Kansan, on which rests a layer of dune sand, possibly de- rived from the Iowan, and over this appears another deposit of later loess. While neither Kansan nor sub-Aftonian appear in this section, the posi- tion of the bed below the older loess, the similarity of its cross-bedding, etcetera, to that of undoubted Aftonian, and the presence of Aftonian fossils, such as fragments of Spherium, and bones of large mammals, such as Hlephas and Cervalces, all indicate that the beds are Aftonian. That the beds herein discussed are not merely a comparatively recent outwash covered by a slumping of the Kansan along the bluffs of modern valleys is demonstrated by the fact that well-sections show that they run well back into the bluffs. Thus about 15 rods back from the Cox pit a well excavation revealed Aftonian beds 40 feet below the surface, which is here about 60 feet above the top of the Aftonian in the pit. At Logan, a well dug about 5 rods from the face of the bluff showed Aftonian sand at a depth of about 28 feet. The exposure shown in plate 39, figure 2, 1s only a short distance above (north) of this well, and also furnishes evidence of the same kind, for the excavation here extends at least 3 or 4 rods into the bluff, vet the Aftonian 1s well developed. A well east of the Wallace pit, near Little Sioux, Iowa, penetrated into a bed of gravel at a depth of about 90 feet. The well is on a high bench 83 See plate 33, figure 2. 34 See plate 35, figure 1. 3° See plate 35, figure 2. 86 This has been referred to as ‘‘gumbo”’ in the type locality at Loveland by Udden and the writer (see Bulletins from the Laboratories of Natural History of the State Univer- sity of Iowa, vol. 5, 1904, p. 348). It evidently bears the same relation to the Kansan as the Buchanan gravels, and the name Loveland is here proposed for it. 406 B. SHIMEK——AFTONIAN SANDS AND GRAVELS IN IOWA several rods back from the bluff in which the pit is located. The gravel in the well is probably Aftonian. Other well-borings, though less definite, also indicate that the Aftonian gravels extend well into the bluffs. THE -AFTONIAN INTERGLACIAL WITH MILD CLIMATE That these sands and gravels belong with neither the sub-Aftonian nor - Kansan drifts is shown by the following evidence: . 1. They are not sub-Aftonian, because in every case examined they lie unconformably on the older drift, the old oxidized and weathered surface of which sharply marks the line of division between the two deposits.*’ 2. They are not Kansan, for in nearly all the exposures Kansan is shown clearly resting unconformably on them, with calcareous plates (nodular), cemented sands and gravels, and strongly oxidized materials © sharply defining the line of division.** Moreover, evidence is furnished by several exposures that the Kansan passed over the Aftonian beds while the latter were frozen, and plowed and tilted them in mass or disturbed and folded them in intricate fashion. Thus in the McGavern pit, south of Missouri Valley, the Kansan pre- sents a sharp but very irregular line of contact with the Aftonian, and cross-bedded and stratified masses of the latter are twisted and folded until in some places they are nearly vertical. This is shown especially well in plate 36, figure 2, which represents the south end of the section shown in plate 36, figure 1. Here the line between the Kansan and Aftonian is very sharp, and the former is shown projecting into and against the latter, which has had its strata pushed into an almost vertical position. The Murray Hill exposures*® show that both the Aftonian and sub- Aftonian were crowded and folded by the Kansan. The Aftonian gravels have been here pushed up to an unusual height—as noted, more than 100 feet above the valley. In these exposures sub-Aftonian and Aftonian masses (“boulders”) are common in the lower part of the Kansan, which had evidently not only moved great masses of frozen gravels (for the latter, even when most folded and tilted, show the original stratification and cross-bedding), but also plowed into the underlying sub-Aftonian, which is sometimes folded, and shows cleavage, concentric with its face or front, evidently due to the great pressure of the advancing Kansan. _ A pit below Woodbine also shows a tilted layer of Aftonian, with a mass of mingled and folded sub-Aftonian, Aftonian, and Kansan in front of it, as though the whole tilted Aftonian mass had been moved forward. 37 See plate 34, figure 1. 35 See plate 33, figures 1 and 2; plate 34, figure 2, and plate 35, figure 1. *® See plate 37, figure 1. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 36 FIGURE 1.—LOOKING ALMOST HAST (a) Kansan; (U0) irregular line of contact, showing folding; (c) Aftonian, more or less disturbed FIGURE 2.—LOOKING EAST or SouTH (a) IXansan; (6) contact line; (c) tilted Aftonian gravel, evidently pushed into an almost vertical position by (a) McGAVERN PIT, SOUTH OF MISSOURI VALLEY, lOWA BULL. GEOL. SOC. AM. VOL. 20 1908, PL. 37 FIGURE 1.—-A FOLDED AFTONIAN BED (a) Kansan; (0) oxidized and folded bed of Aftonian gravel; (c) Aftonian white sand FIGURE 2.—THE LOVELAND BLUFF, POTTAWATTAMIE COUNTY (a) Sub-Aftonian, more or less folded, and the upper part with sand cemented into blocks; (0) Kansan; (c) red joint clay, the Loveland; (d) loess EXPOSURES SHOWING FOLDED AFTONIAN GRAVELS EVIDENCE THAT THE BEDS ARE AFTONIAN 407 Other exposures showing the folding and tilting of Aftonian gravels by the Kansan are found near Mapleton and Grant Center, in Monona county; Pisgah, in Harrison county; Smithland, in Woodbury county, and Loveland, in Pottawattamie county. All the larger pits already men- tioned also show this in their uppermost portions.*° 3. The sand and gravel beds are not glacial, but interglacial. That the materials were deposited in streams is shown by the fact that they are water-worn, cross-bedded, with frequent interbedding of sand and gravel, the latter deposited by stronger currents, and that they contain fluviatile shells, with such intermingling of land shells as is common in the same region in modern alluvial deposits. That the climate was mild during this interglacial period is shown by the presence of the large numbers of herbivorous mammals, which re- quired a vigorous flora for their maintenance, and of fresh-water and land mollusks, which are identical with species now liying in Iowa. The aquatic shells suggest the same biotic conditions as exist in the state today, and the land shells required plant-covered land surfaces on which they could find food and shelter, and these surfaces were not radically different from those which prevail in Iowa today, if we are to judge from the identity of the land shells. The abundance of MnO, in the Aftonian beds also suggests the presence of a large amount of organic matter. THE AFTONIAN IN OTHER COUNTIES The Aftonian beds extend also into counties other than Harrison and Monona, in the western part of the state. Thus the gravels at Sioux City,*t in Woodbury county, between Loveland and Council Bluffs, in Pottawattamie county, at Denison, in Crawford county, and between Glenwood, in Mills county, and the northern part of Fremont county, are certainly Aftonian, as the writer has ascertained by personal examina- tion, and those described by Bain from Plymouth county* and by Udden from Mills county** are evidently the same. Thus it will be seen that the Aftonian is well represented in the western part of Iowa. CONCLUSIONS The conclusions may be briefly stated as follows: 49 A fine illustration of the same kind is also found in the eastern part of the state, in Muscatine, near Hershey avenue, where the Aftonian and sub-Aftonian have been plowed and folded by the Kansan in a most complicated manner. 41 See H. F. Bain’s account in the Report of the Iowa Geological Survey, vol. v, 1896, Deak. 44Reports of the Iowa Geological Survey, vol. viii, 1898, p. 338. 43 Tpid., vol. xiii, 1903, p. 165. XXXVI—BouULL. GOL. Soc. AM., Vou. 20, 1908 408 B. SHIMEK—-AFTONIAN SANDS AND GRAVELS IN IOWA 1. Extensive deposits of sands and gravels in the western part & Towa are definitely referred to the Aftonian stage. 2. A distinct and quite extensive molluscan and mammalian fauna is revealed in these Aftonian beds for the first time. 3. The climate of the interglacial Aftonian stage was mild. 4. The Aftonian beds are widely distributed along ancient and modern river courses in Iowa. AFTONIAN AND NEBRASKAN—AN ADDENDUM , Since this paper was written the writer has made additional observa- tions on the Aftonian and sub-Aftonian deposits, especially along the Missouri river in Iowa and Nebraska, and along the Big Sioux river, and in various other localities in Iowa. These observations demonstrate that both deposits are of very wide extent. Additional fossiliferous Aftonian beds were found near Omaha, Ne- braska, and in Plymouth and Woodbury counties in Iowa, and much additional material was obtained from the exposures previously studied, especially those at Missouri valley and Turin, Iowa. Quite recently the writer discovered extensive beds of Aftonian sands and gravels, the latter frequently massed into ledges of conglomerates, resting on well developed strata of pre-Kansan, or sub-Aftonian drift, in South Omaha and near Florence, Nebraska, and between Council Bluffs and Crescent, Iowa. The tough, impervious, bluish-black till which has been known as the sub-Aftonian or pre-Kansan drift in Towa, is here so well developed, reaching an exposed thickness of more than 15 feet and extending for several miles along the base of the bluffs on both the Ne- braska and Iowa sides of the Missouri river, and moreover occurs at so many other localities in Towa, Missouri, and Nebraska, that it can no longer be regarded as merely a remnant, but should rank with other well developed drift sheets. The terms pre-Kansan and sub-Aftonian have been used merely to designate the position of this drift sheet; the name Albertan was origin- ally applied to a deposit which can not be correlated with this drift, and which is not now regarded as glacial; and the doubtful Jerseyan can not be connected with the sheet here discussed. This leaves it without a name, and in view of this fact, and of the wide distribution of this forma- tion, the name Nebraskan is proposed for it. The type exposures are located in the Missouri bluffs in South Omaha and above Florence, Nebraska, and 4 miles north of Council Bluffs, Iowa. The name Nebraskan was suggested to the writer by Professor Calvin. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 409-416, PLS. 38-42 DECEMBER 31, 1909 STRIATIONS AND U-SHAPED VALLEYS PRODUCED BY OEM EAN ClHACTAL EAC LION: BY EDMUND OTIS HOVEY (Presented orally before the Society December 29, 1908) CONTENTS Page PTUs orb TONA | OPUS M re rey caters el OIG e oc -ginah oul Clete aes ay Seow, eiaie Tete oye! eos, Ciel! 6 Ola! Revers Ov clavane 409 Perera TAIAG HT GUMMY A cues ct cira, tole avs’ cid) Ala (eres ole Be: ordi el nie\'el aise! @ evel o@ felon raieleieuace eve ce eels 6 8/6 410 Soa waster1ehHOn OM MOUNtsP ClO si 6.60.1 6c.ccec 5 ete sd douse eos iad ae cree 410 EMA eneAChION OM: MOUNT Cl sya tit sae ae eve lone Mev ag © eco) eles susvwhelo eran ees 412 Sand-plast action on the Soufriére.... 6.0.0.0... css ccc cece as scce ces 413 EELS RMRVEELLE VS ciel cle 5 nroccle ei oae Gio oh eiese eieies chal sierels @iae sid ol elelatS era rquanals goa Wrelwes 413 INTRODUCTION Geologists and others are so much in the habit of considering striations and grooves in rock surfaces, U-shaped valleys, and hanging valleys to be conclusive proofs of glaciation that it will be of interest to cite some par- ticularly striking instances of such features that have been in no way connected with ice action. The illustrations accompanying this note tell . the whole story. They have been selected from the photographs taken by me upon three expeditions to the Lesser Antilles undertaken for the American Museum of Natural History in 1902, 1903, and 1908. The conditions were either consequent upon or revealed by the 1902-1903 eruptions of Mount Pelé of Martinique and the Soufriére of Saint Vin- cent. Perhaps similar features may be known elsewhere, without an ex- planation having been apparent. The eruptions of Mount Pelé in 1902 and 1903 were characterized by the emission of unnumbered, probably hundreds, of exploding steam- clouds which were saturated with dust formed of comminuted lava (augite- andesite). It is evident that an enormous excess of water vapor was con- tained in the lava and that the vapor was under great pressure in the ! Published by permission of the American Museum of Natural History. Manuscript received by the Secretary of the Society August 30, 1909. XXXVII—BULL. Gro. Soc. AM., VoL. 20, 1908 (409) 410 E. 0. HOVEY—STRIATIONS AND U-SHAPED VALLEYS liquid rock. As the lava reached the orifice of the conduit, pressure was relieved suddenly, and the steam expanded and continued to expand with explosive violence, breaking up the lava to all degrees of grain, from great blocks 10 meters or more across down to impalpable dust. The fragments when formed were angular, but attrition in the eruption cloud and against the surface of the ground rounded the contours of the grains, particularly the larger ones and the great masses. Under the microscope the fine dust is seen to be highly and sharply angular. In the field the ejected blocks usually show bruised and rounded angles and corners. The first eruption clouds, furthermore, reached the surface in the bottom of a vast pit-like crater about 1 kilometer across. Their force of explo- sive expansion was confined on three sides by practically vertical walls from 300 to 650 meters high, but the southwest side of the rim was breached to the bottom of the crater by a great V-shaped cleft. These two factors? prevented the free expansion of the exploding cloud and gave direction to it, confining it to a narrow sector of a circle, bounded on the northwest by the high bluffs along the right bank of the Riviére Claire, but without any sharp surface delimitation on the other side. This was the “zone of annihilation” often referred to in my own and other early reports upon the eruptions. The content of dust in the cloud was such as to make part of it heavier than the atmosphere, so that it clung to the ground, rolling and sliding over its surface. STRIATIONS SAND-BLAST ACTION ON MOUNT PELE Within the sector thus described all the bluffs facing the crater were smoothed, scored, and grooved as if by the action of a stupendous sand- blast or the passage of a well sanded glacier. This sand-blast action at Pelé has been noted by Professor Lacroix,? me,* and Doctor Anderson,® but only in a preliminary or very cursory manner, whereas the occurrence is worthy of more extended notice. 2Some authors have argued for the existence of an inclined opening to the volecano’s conduit to explain the marked orientation of the eruption cloud. The assumption of such specific inclination of the vent seems unnecessary, since the two factors mentioned would be sufficient to produce the effect, but a discussion of the cause of the confinement of the destructive blast to a narrow zone is beside the purpose of the present article. 3A. Lacroix: Rollet de l’Isle and Giraud. Comptes Rendus de 1’Acad., exxxy, p. 387. Meeting of September 1, 1902. A. Lacroix: La Montagne Pelée et ses Eruptions, 1904, p. 217. “Bull. American Museum of Natural History, vol. xvi, October, 1902, p. 363, pl. xlix, fig. 2. American Journal of Science, IV, vol. xiv, November, 1902, p. 345, fig. 15. Comptes Rendus, ix, Congr. Géol. Internat., 1904, p. 716. 5 Philosophical Transactions of the Royal Society of London, series A, vol. 208, 1908, p. 300; pl. 25, figs: 1, 2: BULL. GEOL. SOC. AM. VOLES 20; 1908 aR os BPIGuURE 1.—MouN’rT PELE: Rock MASS AND TUFF AGGLOMERATE OF CRATER RIM Showing grooving due to sand-blast action of eruption clouds WIGURE 2.—MORNE LENARD, MOUNT PELE The nearly horizontal grooving was caused by sand-blast action of eruption clouds d VOLCANIC SAND-BLAST ACTION ON MOUNT PELE afl ” STRIATIONS FROM SAND-BLAST ACTION Ali Standing like a sentinel upon the west rim of the crater, and forming the northern point of the V-shaped cleft often referred to, was the mass of old lava known as Petit Bonhomme. This rock-mass was directly in the path of all the heavy eruption clouds. It is scored with horizontal and inclined grooves on the vertical north, east, and south faces. An- other rock-mass even more beautifully striated is one in the south side of the V-shaped cleft and about midway of the original vertical height of the wall (see figure 1, plate 38). These two examples are nearest to the eenter of activity and are particularly instructive, because they show grooving and polishing of massive rock, the grooves being many meters long, but of undetermined depth. | The V-shaped cleft was at the head of the old gorge of the Riviere Blanche, and that gorge was the course of many dust-laden steam-clouds (the nuées ardentes of Lacroix). The origin of the first of these clouds has been explained. Directly after the first great outbreak the activity of the voleano manifested itself in building up out of “solid” lava (that is, of original material, not of débris) a cone within the old crater. The material was extremely viscous and it hardened as it rose from the conduit, a process that was favored by the expansion of the contained water vapor, which rapidly reduced the temperature of the mass below the point of solidification. An extremely steep-sided cone or dome was the result, with vertical walls and 37 degree slopes of slide rock on its southwest side above the head of the old Blanche gorge. As the cone rose, the explo- sions occurred most frequently and violently in the southwest section of its upper part. ‘The dust-saturated clouds therefore rolled down the steep slope of the new cone, gaining velocity and force as they went. The velocity attained by many of the clouds in the upper part of their course (as far as Morne Lenard) was determined by angular measurements from the French observatory on Morne des Cadets, only 9 kilometers distant, to be as much as 50 meters per second. The cloud that swept over Saint Pierre on the fatal 8th of May had a velocity of not less than 130 to 150 meters per second 8 kilometers from the crater, as is shown by the moment of the force required to overturn the iron statue of Notre Dame de la Garde on the bluff of Morne d’Orange, south of the city (Lacroix). Such dense clouds moving with such velocity were of course able to do much erosive work. ‘Two examples of what was done on surfaces of solid andesite have been given, but illustrations of the effect produced on the old tuff-agglomerate composing the major portion of the mountain were much more numerous. About 1.8 kilometers below the V-shaped cleft in the rim of the crater the gorge of the Riviere Blanche turns sharply westward through an angle 412 E. 0. HOVEY—STRIATIONS AND U-SHAPED VALLEYS of 90 degrees to skirt a ridge called Morne Lénard.* Between Morne Lénard and the main mass of the mountain there is a comparatively low col over which rushed part of each cloud that was divided into two parts on striking the narrow front presented by the morne. The surface of the ground here was completely denuded of soil and the tuff-agglomerate was scored with hundreds of parallel straight grooves many (10 to 15) meters long and several (2 to 10 or more) centimeters deep. Such grooves in the side of Morne Lénard are shown in figure 2, plate 38, made from a photograph taken in May, 1908. Figure 1, plate 39, is a near view of a part of the same surface, taken in February, 1903. The latter view shows, too, the manner in which the comparatively hard component frag- ments of the agglomerate were planed off without being dislodged from the softer matrix. Such fragments when removed from their present surroundings, either naturally or artificially, would make good imitation “olacial bowlders ;” or the whole surface, if buried beneath an accumula- tion of volcanic débris, would have close resemblance in appearance to a glaciated surface under a covering of till. ‘The photograph given in fig- ure 2, plate 38, furthermore brings out well the rounded, glaciated ap- pearance of the morne as viewed from the east and north, the lower part closely resembling a true glacial roche moutonnée. Other bluffs showing the sand-blast action typically were observed along the right bank of the Riviére Claire, on the right bank of the Blanche opposite Morne Lénard, on both walls of the Riviére Séche gorge (see figure 2,” plate 39), and elsewhere—in fact, wherever in the zone of annihilation a surface was opposed to the advance of the eruption clouds. The direction taken by the strize depended on the position of the striated surface with relation to radii drawn with the crater as a center. AVALANCHE ACTION ON MOUNT PELE The Morne Saint Martin is a rather flat ridge sloping away from the crater and not fully exposed to the fury of the volcanic sand-blast. Here corrasion was observed, with grooves and strie running at an angle to the radii of the zone of annihilation which were not to be accounted for by reference to the eruption clouds for their origin. This flat ridge is mid- way of the mountain and has a slope of 10 to 15 degrees, the slope below being from 3 to 5 degrees, and the slope of the outside of the old cone above being about 20 to 28 degrees. During intervals of mild activity 6 Erroneously called Morne Saint Martin in my earlier papers. The real Morne Saint Martin is a less prominent ridge south and east of Morne Lénard. ™This is a near view of part of the scored bluff illustrated in Bull. American Museum of Natural History, vol. xvi, pl. 49, fig. 2. BULL. GEOL. SOC. AM. VoL. 20, 190S; PE. 39 FiIGuRE 1.—MorRNE LENARD, MOUNT PELE Near view of volcanic sand-blast action. The rock is tuff agglomerate FIGURE 2.—VERTICAL CLIFF BESIDE RIVIDRE SHCHE, GROOVED OBLIQUELY BY VOLCANIC SAND-BLAST / VOLCANIC SAND-BLAST ACTION ON MOUNT PELE RESULTS FROM AVALANCHE ACTION 413 ash accumulated to a thickness of 15 to 30 centimeters or more on the steep part of the old cone near the crater. From time to time the coat of new material became water-soaked from the heavy tropical rains and slid down the mountain in more or less of a sheet avalanche. On the collect- ing ground of the steep upper cone planation and grooving were not prom- inent, but on the middle ground of the Morne Saint Martin, where the force of the avalanches spent itself, planation and grooving were pro- nounced. In June, 1902, the striated surface of the old agglomerate, with here and there a heap of unassorted ash upon it, suggested closely the appearance of a regularly glaciated surface with its overburden of till. At the lower end of the slope of the morne there is a flat transverse valley, with a short, abrupt rise below it, before the lower slope of 3 to 5 degrees begins. The avalanches were checked here and diverted into the canyon of the Riviére Séche, apparently doing no more planation of the kind described. Rounded and subangular pebbles and bowlders were seen in abundance in the new ash, but none was noticed showing striations to indicate that it might have been an agent or one of the tools in producing the sand-blast or the avalanche abrasion, though it seems as if diligent search might have brought some to light. SAND-BLAST ACTION ON THE SOUFRIERE Such sand-blast work as that just described as occurring in many places on Mount Pelé was likewise observed on the Soufriére of Saint Vincent, but through the nature of the old agglomerate and the fact that the soil was not so extensively removed, the evidences of the abrasion seem now to have been obliterated by atmospheric erosion and the growth of vegetation. In 1902 an interesting feature of the sand-blast erosion was the sharpen- ing and charring of the ends of tree roots and branches that pointed toward the crater. Planing due to the sliding of the new ash over the old agglomerate ridges was not noted in Saint Vincent, but the eroding power of sliding water-soaked ash and ash-saturated water was manifest in another and perhaps more interesting fashion—by the excavation of the U-shaped valleys about to be described. U-SHAPED VALLEYS Several of the radial valleys on the Soufriére of Saint Vincent show the U-shaped cross-section in a rock gorge that is usually thought to be con- fined to valleys that have been excavated by the action of glaciers. These Saint Vincent valleys, though small, are typical, the best and most accessi- 414 E. O. HOVEY—STRIATIONS AND U-SHAPED VALLEYS ble that I have seen being the Larikai and Roseau gorges in the western (leeward) side of the volcano. In the Larikai gorge, about 500 meters from the sea, the bottom of the canyon is crossed by a broad, heavy bed of andesitic lava. In this rock there has been carved the perfectly U-shaped channel that is shown in figures 1 and 2 of plate 40. This is 8 to 10 meters wide, 4 or 5 meters deep, and about 50 meters long. The explanation of this form of cross-section is hinted at in figure 2, plate 41, which shows an overloaded streamlet in the Larikai gorge depos- iting its excessive burden of sand and gravel in a rock basin at the foot of a fall (see also figure 2, plate 42). This illustrates the tendency of moderate showers to bring down loose material from the steep slopes of the watershed and fill the hollows in the bottom of the gorge (see also figure 2, plate 40, and figure 1, plate 41) and the gorge itself. Another circumstance contributing to the filling of these gorges with loose, angular material is the constant disintegration undergone by the almost vertical bluffs of new ash surmounting the equally steep old ash. During dry weather there is a continual shower of pebbles and sand grains down the faces of the bluffs, building débris cones at their bases, as is shown in figure 1, plate 44. Going back still farther, we know that the eruptions of 1902-1903 threw enormous quantities of lava fragments of all sizes into the gorges and onto the slopes draining into them, and filled more or less completely the radial valleys of the mountain, furnishing vast store of abrasive material for eroding the gorges (figure 1, plate 42, and figure 1, plate 43). The bottom of the old gorges being filled to a greater or less extent by one or all of these ways, torrential rains such as are frequent in the tropics, particularly in the rainy season, soak the accumulations of loose ash and gravel past the point of equilibrium and the semi-fluid mass rushes with violence down the slopes and through the gorges into the sea. Figure 2, plate 42, shows such a mud flow falling over a precipice into the sea from the valley next north of the Larikai valley, Saint Vincent. The viscosity of these mud flows and their resultant transporting power was patent to every observer of the Mount Pelé and Soufriére eruptions. On my first expedition to Martinique I crossed the gorge of the Riviére Séche, June 24, 1902, barely in advance of a torrent of black mud 3 or 4 meters deep that bore along on its surface bowlders 1.5 meters in diameter as if they had been corks. A flood in the Riviere de Basse Pointe, June 9, 1902, brought down from the mountain a huge rounded bowlder 3 meters across, which it left perched on a pier of the railroad bridge near the Usine Gradis, 4.5 meters above the bed of the stream, after the flood had sub- sided. Such examples of the viscosity of the mud torrents following on GEOL. SOC. AM. , VOL. 20, 1908, PL. 4 FIGURE 1.—LARIKAI VALLEY, THE SOUFRIDRE, SAINT VINCENT shaped rock gorge, about 500 meters from the sea, looking up stream FIGURE 2.—WLARIKAI VALLEY Looking down stream through same gorge. Shows accumulation of sand in the hollows U-SHAPED ROCK GORGES OF THE SOUFRIERE 2. in, ae So. LU a . Zz — EE ——— S _ —— auY¥aldsnos AHL dO SADYHOS GadVHS-N UISLG OY} UL puvS JIURdIOA SuTjISOdep eov[d Ul 11S YSe sit SI JO[UIVII}S PopvVO]IVAG ‘VAS OY} WOT SloPOMIO[IY GT JNOGe os10s Yoo jo yavd GIIM “EGOGTL ‘Gorey Ul porvodue 41 SB OF 9} RIA UL UMOYS 98103 aq, AWTIVA IVMIUWI—s% UNV] , AQTIVA IVMIUVI—'[ wywasiy f Lb “Id ‘8061 ‘03 “10A “WV “OOS “10389 °11N8 ORIGIN OF THE U-SHAPED VALLEYS 415 the deforestation of the mountains and the deposit of a mantle of loose ash on the denuded slopes might be greatly multiplied from both Mar- tinique and Saint Vincent, but those given suffice to make clear the points that the valleys under consideration have been traversed frequently by streams of thick pasty or semi-fluid matter, and that these streams were armed with angular and subangular sand and gravel, by means of which they excavated U-shaped gorges in the beds and dikes of rock encountered in their course. It is improbable that this corrasion of a U-shaped section should con- tinue after the watershed becomes covered again with vegetation, because then there will be no accumulating supply of loose angular material to form mud flows and provide the floods with grinding tools. Nor is it at all likely that the phenomenon described is a new one or has been pro- duced even in Saint Vincent by the recent eruption alone. The rock beds in which these U-shaped gorges are so beautifully developed lie in the lower reaches of the Larikai, Roseau and other valleys through which has been carried débris of the numerous eruptions of the Soufriére that have constructed the entire upper 1,000 meters of the volcano. Where the crevicing of the rock-mass has been favorable, the impact of stones hurtling down the stream bed has broken off chips from the bed rock, producing a good imitation of the “chatter” marks made by a glacier. The cross-section of the gorges of the headwaters of the Wallibu, the principal stream of the leeward side of the mountain, was not observed except from above, on account of the inaccessibility of the region. The lower and accessible part of the Wallibu gorge is through beds of old agglomerate, with here and there a comparatively small bed of old lava. The very bottom of the gorge is usually concealed by the fresh débris brought down since the recent eruptions, but where the sides are of the agelomerate they come abruptly and sometimes almost at right angles to the floor. The stream is aggrading this part of its bed. About 3 kilo- meters from the coast one encounters rock forming the bottom of one side of the gorge and suggesting a U-shaped section, except where the columnar structure of the lava beds has caused the section to be nearly or quite rectangular. All the streams of the denuded portion of the Soufriére on its wind- ward side are tributaries of the Rabaka river. The principal are four in number, and they have deeply incised the side of the cone, exposing to _ view several massive beds of lava forming the floor of the valleys at dif- ferent levels. Hach bed ends down stream in a precipice, hence there are 416 E. 0. HOVEY—STRIATIONS AND U-SHAPED VALLEYS several waterfalls in the region when the rains furnish water. Great quantities of gravelly débris and large and small bowlders have been car- ried down these water courses into the Rabaka by the floods which have traversed them since the eruptions removed the protective covering of vegetation and furnished an abundance of new loose material; but the stream beds are wider, the bordering material is the tuff agglomerate which tends to make a V-shaped section beside a degrading stream, and the U-shaped section has not been clearly developed. The Wallibu and Rabaka River valleys are described and discussed more in detail in the following paper. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 42 FiIGuRE 1.—ROSEAU VALLEY, SOUFRIERE, SAINT VINCENT Ash-filled middle reaches, May 31, 1902 dt nanan stone apnea Sate FIGURE 2.—MUD-FLOW FALLING OVER PRECIPICE INTO THE SEA A “hanging valley”? of the Soufriére GORGES OF THE SOUFRIERE, SAINT VINCENT Sr IO NE i er a BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 417-426, PLS. 43-45 DECEMBER 31, 1909 CLEARING OUT OF THE WALLIBU AND RABAKA GORGES ON SAINT VINCENT ISLAND? BY EDMUND OTIS HOVEY (Presented orally before the Society December 29, 1908) CONTENTS Page Aa ARIM CAE Crt OTD RR ee a og hes ei7s) Fo gaits Pac orteireyeriatin'de\ Fan evel al bras at wun e eto elay 6 Oo haya e bieroke wee 417 ee AOL CEPA TVA LLCY: > tos acre oe avdce o 6c05 elolere eee boca oo a, chen pee eile d. soe whee 418 MiIMNMTeT OL SEreEAM WOPK. .. 0. s.c ce e ewe eee wee RANMA er hae an okra arte ame Beat 419 ERNE TEES TOPIC UTIL eich ee Sefe ney ciel ooo at cl eke i hahenet a: o.-0h Oe wel aca TAYE UaTA TEN eds ete race Chute eres 423 WSU SVEE, JSTRYGVE Sue ge Ne a a en Ger ok ete en te as ee ee RP 424 MI ea IOUS RUSTE LTTE 5 ts to oh.c. «sass lols Set ove Tol Sha» dtl vie; severe ila alebe big wluraiie: cea ae 6 Sub atis 425 INTRODUCTION Interesting phases of the process of carrying to the sea the vast quan- tity of debris thrown out by a great volcanic eruption are shown by the history of the gorges of the Wallibu and Rabaka rivers, Saint Vincent, British West Indies, since May 7, 1902, when the volcano known as the Soufriére suddenly resumed violent activity. Practically the entire catch- ment basins of these streams were affected by the eruptions. The northern half of each les upon the southern slopes of the volcano, and therefore felt the full force of the avalanches of débris and the blasts accompanying the rolling clouds of dust-laden steam. On these slopes the vegetation, including the big forest trees with few exceptions, was — completely destroyed or swept away, together with most of the soil, and a deposit some meters thick of new ash was laid down on the ridges, while thicker accumulations formed in the valleys. The southern halves of the basins lie on the northern slopes of the Morne Garu mountains, facing the crater. These received a thick mantle 1 Published by permission of the American Museum of Natural History. Manuscript received by the Secretary of the Society August 30, 1909. XXXVIII—BULL. Grou. Soc. Am., VoL. 20, 1908 (417) 418 E. 0. HOVEY—WALLIBU AND RABAKA GORGES of ash, and the surface vegetation was mostly destroyed, though the vegetable mold and soil were not much disturbed, being simply buried. WALLIBU GORGE AND VALLEY The immediate gorge of the Wallibu is bordered by bluffs ranging from 50 to 150 meters in height. Where the stream issued from the bluffs of solid old-land at the sea beside the Richmond estate the gorge is about 215 meters wide, as determined by pacing, and it gradually diminishes to less than 5 meters about 3 kilometers from the sea, where the permanent stream flows through a defile, the right bank of which was formed by agglomerate, the left by the edge of an old lava bed. The water filled the whole width of this defile, and was so deep and turbulent when I visited the spot (March, 1903) that I progressed no farther in my explorations of the bottom of the gorge. Above this point, however, the gorge widens out again. It is impossible, perhaps, to estimate closely the amount of material deposited in the areas drained by the two rivers in question, but it is probably well within the bounds of fact to say that the average depth of the débris left in the Wallibu gorge was not less than 30 meters, while that in the gorge of the Rabaka was at least as great.2 The depth of new material thrown into the side ravines was likewise to be measured by meters. The mantle of compacted dust (mud) along the southern rim of the crater and on the upper slopes of the mountain draining into the Wallibu was from half a meter to 2 meters in thickness in June, 1908, after the loss of material due to the erosion of six rainy seasons. There is every reason to suppose that as much or more ash covers the head slopes of the Rabaka, but no sections of the deposit were observed here in June, 1908. In June, 1902, however, Mr G. C. Curtis and I came near losing our way in gullies 2 to 4 meters deep in the new ash at the head of one of the tributaries of the Rabaka, and more ash was cast on the slopes in subsequent outbursts. To one who has been over the ground an estimate of 5 meters will not seem excessive for the average depth of the ash over the “area of annihi- 2 The estimate of 200 feet for the depth of the filling of the Rabaka gorge, as given by myself (Bull. American Museum of Natural History, vol. xvi, p. 343) and Doctors Ander- son and Flett (Philosophical Transactions of the Royal Society of London), were derived from the same source, a Mr A. H. Spence, of Saint Vincent, and seems to have been ex- cessive. The vertical sections quoted in a later part of the present paper show the depth of the new filling to have been from 30 to 35 meters deep where the Rabaka issues from the hills. Farther up stream the deposit was somewhat deeper, but 40 to 45 meters seems to be the maximum that can be assigned to the original depth of the new débris thrown into the gorge by the 1902-1903 eruptions, BULL. GEOL. $0C. AM. FIGURE 1.—WALLIBU GORGE, MAY VOL. 20, 19C8, PL. 48 30, 1902 Nearly full of newly-fallen ash FIGURE 2.—WALLIBU GORGE, JUNE 18, 1908 Terraces show varying heights at which fillin o b=) of new ash has stood WALLIBU GORGE, SOUFRIERE, SAINT VINCENT 2, a — = 4 . . 3 = . i a “ pe ? i! ‘4 EFFECT OF STREAM WORK 419 lation.” This area was about 102 square kilometers (40 square miles), and on this assumption the amount of ash deposited on this restricted surface was about 510,000,000 cubic meters, or nearly one-eighth of a cubic mile. Reckoning the catchment basin of the Wallibu at one-tenth and that of the Rabaka at one-eighth of the area in question, we have 51,000,000 cubic meters as having been deposited in the former and 63,750,000 cubic meters in the latter. Guesses are hazardous, but it seems probable that at least one-half of this large quantity has been washed down from the slopes and carried into the sea. In 1903 I estimated* that not less than 5,500,000 cubic meters of ash had been washed out of the Wallibu gorge alone in the ten months from the beginning of May, — 1902, to the beginning of March, 1903. Much more has passed out by the same route since. MANNER OF STREAM WORK The struggles of the streams with the débris began as soon as the erup- tions deposited their loads. The rain from moderate showers sank at once into the mass of the ash and produced no other effect at first than to cause abundant explosions or secondary eruptions, as the water pene- trated to the heated interior of the ash bed. From time to time these secondary eruptions were of imposing magnitude, one observed by Mr Curtis and myself on May 30, 1902, throwing its column of dust and mud laden steam to an estimated altitude of about 114 kilometers.* I can not, however, agree with the hypothetical section proposed by Mr Curtis in the article to which reference is made or altogether with his explanation of the phenomena. His section’ is faulty in that the gorge of the Wallibu does not have the V-shaped profile suggested therein, and the arrangement of material in it was not that assumed by him. As is indicated by figure 2, plate 43, the valley is broad in proportion to its depth (that is, in its lower courses—the portion under consideration) and is flat-bottomed, or nearly so. The present (1908) bottom is still 6 or more meters above the grade level reached before the eruptions; but the walls are nearly or quite vertical, and the breadth of this part of the valley is so great in proportion to the depth of ash still remaining in it that it is evident that no V-shaped section can be present here. * Comptes Rendus, IX Congrés géologique international, 1904, p. 729. 4Hovey: Preliminary Report, etc. Bull. American Museum of Natural History, vol. xvi, 1902, p. 3438. Curtis: Secondary phenomena of the West Indian volcanic eruptions. Journal of Geology, vol. xi, February-March, 1903, p. 200. oc, cit., p. 211. 42.0 E. 0. HOVEY—WALLIBU AND RABAKA GORGES Furthermore, Curtis’s figure represents the big fragments and bowlders as being concentrated in the bottom of his V-shaped gorge, to form a sort of accumulating region or channel for underground waters. This theory assumes that the big masses were thrown into the gorge first and the gravel and sand afterward, which can not have been strictly the case. Material of all sizes was thrown out together from the crater, and some sorting would naturally have followed deposition from clouds suspended in the air, but as a matter of fact the natural sections of the ash beds show that masses as much as 30 to 50 centimeters across were relatively scarce and scattered irregularly throughout the ash beds. Where they have reached the bottom of the gorge it has been mostly, at least, through being left behind on the removal of the finer material. The filling of the gorges was done for the most part by the rolling, sliding débris-avalanches that formed part of each great eruption cloud, in which there was little opportunity for assorting material according to size. Water sinks and flows more rapidly through coarse material than it does through fine, but the exposed sections of the new ash show the presence of enough irregular lenses of gravelly and bowldery material and clean sand to account for the repeated access of steam and rain water to the heated interior of the beds which was evidenced by the frequent violent explosions that were noted by all observers. With the gradient (3 to 4 degrees) still obtaining for the surface of the floodplain of the lower reaches of the Wallibu, the rapid stream 4 or 5 meters wide and about 1 meter deep that pours through the flat or possibly U-shaped gorge (rock-walled as to one side) of the upper reaches, ending about 3 kilometers from the coast, soon loses itself in the sand and gravel and pursues an underground course to the sea. The length of this subterranean flow varies up to about 2 kilometers, depending upon the volume of water in the stream. In June, 1908, it seemed to require a heavy shower of at least an hour’s duration to bring the river down on its floodplain to the sea. After the stream bed became thoroughly saturated with water, comparatively gentle showers would keep the river running on the surface for many hours, perhaps for days. The tendency of the less important showers is to accu- mulate débris along the lower middle reaches of the stream bed, increasing the gradient of the flood-plain. In the hollows of the original surface of the new ash bed, where its nature did not permit rapid percolation, but was favorable to the accumu- lation of water, pools were formed. These gradually enlarged until they coalesced, and the stream, struggling down from the hill slopes, found its way from one pool to another with varying vicissitudes. Occasionally a secondary eruption would throw a dam across the stream, impounding the BULL. GEOL. SOC. AM. VOLE. 20, 1908, PL. 44 FIGURE 1.—ROSEAU VALLEY, SOUFRIDRE, JUNE 19, 1 Dust and sand cone showing dry landslides as method of bringing new ash within reach of a stream FIGURE 2.—WALLIBU GORGE, SOUFRIPRE, MARCH 7, 1903 Dry, hot dust-flow resulting from a secondary eruption in the new ash GORGES OF THE SOUFRIER , SAINT VINCENT ote EFFECT OF STREAM WORK 421 water until the stream accumulated force enough to overcome its barriers, when it rushed down in pulsations to the sea. By the time of my second visit to Saint Vincent, in March, 1903, the immediate gorge of the Wallibu had been mostly cleared of its filling of ash, except for material retained in protecting curves of the walls, and a considerable amount of material had been washed off from the hill slopes. At that time hot, dry dust-flows were still carrying material out from the sides into the bottom of the gorge (see plate 44, figure 2), showing one method by which the dry season contributed to the removal of the fresh material. The general history of events has been that dust-flows during dry weather and the moderate showers of all seasons have brought material down into the gorge which the torrents due to heavy rains have carried out into the sea. My third visit, in the latter part of June, 1908, was at the end of the dry season, when the effects of this fillmg process were quite evident. An immense amount of volcanic gravel and sand formed a comparatively high floodplain in the mouth of the gorge, and for half a kilometer or more inland from the line of coastal bluffs, ready to be carried out when the rainfalls should provide sufficient water for the purpose. One afternoon during this visit there was a downpour of rain lasting about two hours. This brought the river down on the surface of its bed to the sea in pulsa- tions overloaded with débris, and easily rolling along bowlders 30 or more centimeters in diameter. The stream flowed in the form of waves 30 to 60 centimeters high, whose crests passed the point of observation every 10 to 12 seconds. Following each crest was slack water, with consequent deposition of sediment tending to change the course of the next crest and break it up into rivulets distributed over the broad expanse of the river bed. These pulsations were exactly like those noted in the Wallibu and Rabaka in May, 1902,° which evidently were not a function of either the primary or the secondary eruptions. Neither can temporary dams thrown across the streams by landslides, as postulated by Anderson and Flett, be considered their sole or even principal cause. The explanation ad- vanced independently by Professor Russell and me received ample con- firmation in June, 1908, when frequent showers brought the Wallibu and Rabaka rivers down in pulsating floods, though the voleano had been quiet for years ; the thick beds of hot ash had largely or quite disappeared, and the gorge had widened so that landslides, become comparatively in- frequent, could not possibly have any regularly intermittent effect on the 8H. O. Hovey: Bull. American Museum of Natural History, vol. xvi, 1902, p. 344. I. C. Russell: National Geographic Magazine, vol. xiii, 1902, p. 276. Anderson and Flett: Philosophical Transactions of the Royal Society of London, series A, vol. 200, 1903, p. 430. 422 E. 0. HOVEY—WALLIBU AND RABAKA GORGES streams. Our explanation was that the overloading of the streams with débris caused temporary periodic damming or checking of the water, the waves being due to the accumulated water overcoming the obstruction. _ In June, 1908, the upper level of the floodplain of the Wallibu at the point where the river leaves the old lines of bluffs was about 5 meters above the level of the floodplain before the recent series of eruptions began, as was shown by its relation to a bit of old stone wall that, accord- ing to my guide, an intelligent black man, formed a part of the water- works pertaining to the Wallibu sugar estate which was ruined by the eruption of 1812. The bluffs were about 215 meters apart at their bases, as determined by pacing. The vertical section of the new ash at this point, therefore, may be taken at 5 meters by 215 meters. About 21% kilometers from the sea the river in June, 1908, just as in March, 1903, was flowing in its old channel in the decomposed ash. At this point the bed of the gorge is about 50 meters across. The evidence of the successive stages in the reexcavation of the gorge is given in the terraces bordering the stream at several points. The best series of these, perhaps, is at a distance of about 2 kilometers from the sea (see figure 2, plate 43), where, in June, 1908, six terraces recorded the height to which each successive dry and moderately rainy season filled the gorge, and indicate the down-cutting due to each succeeding season of torrential rains, the “dry” seasons being periods of aggrading stream action and the rainy seasons being periods of degradation. The highest ter- races probably indicate the level of ash filling due directly to the eruption clouds. The slope of floodplain and terraces near the sea was measured at 3, 3.5, and 4 degrees in the Wallibu and other gorges. The condition of affairs between the bluffs at the mouth of the Wallibu, when Doctor Anderson was there in the spring of 1907,’ was completely altered by June, 1908. Doctor Anderson’s beautiful photograph shows a broad ter- race 9 meters high of water-sorted ash at the right (north) side of the gorge, and extending seaward beyond the bluff line, younger terraces ap- pearing at lower levels on both sides of the stream. The stream was flowing along or near the left wall of the gorge. In June, 1908, there was not a trace of these terraces to be seen, all the material having been swept away, and when the stream flowed on the surface it occupied a chan- nel at the immediate base of the great bluff forming the right wall of the gorge. Beginning just within the gateway formed by the bluffs and ex- tending seaward for 200 meters more or less, there was, in June, 1908, a 7 Philosophical Transactions of the Royal Society of London, series A, vol. 208, p. ZS; plo td. CREATION OF THE LEEWARD SHORELINE 423 lenticular terrace perhaps 50 meters wide and three-fourths of a meter high. Doctor Anderson furthermore states that in the winter of 1906- 1907 the river ran along the broad upper terrace which I have just de- scribed from his plate. LEEWARD SHORELINE The chattering vibrations of the mountain due to friction of the erup- tive mass ascending through the conduit of the volcano caused the coastal plain or apron from Richmond village northward for more than 5.5 kilo- meters to be shaken off into the depths of the sea. This apron seems to have been at least 100 meters wide in places—at any rate, the negro vil- lages of Wallibu and Morne Ronde were located on it. At the time of my first visit, in May, 1902, the whole coastline was abrupt except where the larger streams discharged into the sea, and even at these points the under water slope seemed to be steep. The shoreline at the mouth of the Wallibu was almost straight, and was scarcely 50 meters beyond the bluff line of the Richmond and Wallibu estates. The river mouth was embayed 100 to 120 meters at this time, between benches of new and old ash whose tops were 20 to 22 meters above the sea. In March, 1903, the Wallibu had pushed the shoreline of its mouth nearly out to the points of these benches, while the benches themselves had lost some of their sea- ward extent through the action of waves and currents. The shoreline was still but slightly convex, and continued to be at right angles to the line of direction of the lower valley. In June, 1908, the shoreline was strongly convex and apparently 100 meters farther out than in 1903, while the northern bench had lost about half its 1902 extent through ero- sion by river and sea.° It was evident, furthermore, that much of the material brought down by the Wallibu had been spread along the coast northward by the marine currents. The history of the whole coast from Richmond village (just south of the mouth of the Wallibu) northward to Larikai point has been the same—the new or augmented headlands had been cut back by the waves, the deltas of the streams (Wallibu, Wallibu Dry, Rozeau, Morne Ronde, Trespé, and Larikai rivers) had been pushed 8 This statement is directly contrary to one made by Doctor Anderson in his supple. mentary report: “The fan of the Wallibu in 1902 extended beyond the coastline, and was very steep. Gushes of hot mud came down it, and tended continually to build it up. In 1907 it scarcely extended beyond the coastline, and both have receded consider- ably” (Philosophical Transactions of the Royal Society of London, series A, vol. 208, p. 281), but a careful study of my own and other photographs of the mouth of the Wallibu, together with my field notes, confirms me in holding to the statements made in this paper. No accurate survey of the region has been made, as far as I know, since the eruptions began. 424 E. 0. HOVEY—WALLIBU AND RABAKA GORGES out from 50 to 250 meters, a narrow strip of beach had been restored, in- creasing from nothing, or practically nothing, in May, 1902, to 40 or 50 meters in June, 1908. North of Larikai point the losses of the coast in May, 1902, were insignificant, if any were suffered, and the gains in the succeeding six years were correspondingly meager. RABAKA RIVER VALLEY The history of Rabaka river on the windward (east) side of Saint Vin- cent presents an interesting variation from that of the Wallibu. The new ash filled the old gorge completely near the point where it issued from the hills,® with the result that a new gorge to the sea was cut, abandoning the old channel about 3 kilometers from the shoreline. The new gorge was speedily cut down nearly to grade level, and it discharged a large part of the burden of ash in the upper catchment basin of the stream. The new filling of the gorge, therefore, remains as a permanent change in the topography below the point where the new gorge branches off from the old. The Wallibu made a like change in its gorge after the eruptions of 1812, shifting its main channel from the north to the south side of the Wallibu plantation. This change is indicated by the topography and the chart, and note of it is preserved in the history or tradition of the island, according to Doctor Anderson.1° Another permanent change in the drainage of the Rabaka was on the south side of the ash-filled gorge," where ponded waters on the surface of the new ash finally, with the assist- ance of dams formed by secondary eruptions, cut a new gorge through the old wall of the river and ultimately opened a way for the escape of the drainage of a considerable portion of the old basin through that por- tion of the old Rabaka River channel, which extended from the foothills to the sea. New material has been spread out over the preeruption flood- plain of the Rabaka in a mantle several meters thick. Where the Wind- ward Side postroad crosses this plain, about 250 meters from the point of the new delta, the mantle is shown, by a ravine which has not yet cut its way down to grade, to be not less than 4 meters thick. Along this road the old floodplain measures about 450 meters wide. North of this old floodplain there is a narrow strip a few score meters wide of old coast sand, bearing the seagrape, and then comes the new floodplain of the Rabaka, formed since the eruption, which measures about 245 meters ® Hovey: Preliminary Report, p. 343, pl. xxix, fig. 1. 10 Philosophical Transactions of the Royal Society of London, series A, vol. 208, p. 279. 11 Hovey : Comptes Rendus, IX Congrés géologique international, 1904, p. 729. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 45 FIGURE 1.—RABAKA GORGE, JUNE 26, 1908 Great bank of volcanic ash of 1902 eruptions 1s seen at right, trenched nearly to old grade level. Top shows approximately the maximum depth of the débris. Side of original gorge shows at left. Trunks of trees killed by the eruption rise above new growth on the hills. FIGURE 2.—RABAKA GORGE, JUNE 26, 1908. PoINT oF DEPARTURE OF NEW GORGE FROM OLD The oblique line in the bluff is the boundary between the ola tuff agglomerate and the filling of new ash which changed the stream course RABAKA RIVER, SOUFRIERE, SAINT VINCENT RABAKA RIVER VALLEY AQ5 along the postroad. In June, 1908, the main channel, dry except during floods, was beside the old Rabaka sugar and arrowroot mill, part of which had been carried out to sea by the torrents. This channel was 2 or 3 meters deep and 60 meters across. A few meters seaward from the post- road the new and old floodplains merged into one expanse 700 to 725 meters across, forming a new shoreline. The ash that was cast into the Rabaka by the eruptions was coarser in grain and apparently more abundant in quantity than that which was thrown into the Wallibu; hence the middle reaches of the former have been much less thoroughly cleared out than those of the latter, but they show a similar succession of terraces. There are no statistics giving the comparative rainfall of the windward and the leeward sides of the island or of the mountain, so that it is impossible to state accurately which val- ley has had the more frequent showers or the greater amount of water to effect the transportation of the material. The catchment basin of the Rabaka, however, is greater than that of the Wallibu, and the windward side of the Soufriére-Morne Garu region probably receives a heavier rain- fall than the leeward ; hence, other factors being equal, the Rabaka gorge would have been reexcavated before the Wallibu, but the coarse gravel filling the Rabaka gorge allowed freer circulation of water than was possible in the fine sand and dust filling the Wallibu, and the larger, heavier grains required a greater quantity of water or velocity of stream to transport them. Furthermore, the clearing of the Rabaka was delayed by the necessity of cutting the new gorge already mentioned, though the excavation was carried on with great rapidity, once it was begun. WINDWARD SHORELINE Before the eruptions of 1902-1903 began the shoreline at the mouth of the Rabaka was essentially straight, according to the admiralty chart, it being evident that no more material was brought down by the floods of each rainy season than could be distributed by the currents during the succeeding dry months. The immense amount of débris brought down during and after the recent eruptions extended the shoreline at the mouth of the stream in a broad deltal fan some hundreds of meters into the sea, but it is not possible to state just how far, since I neglected to make meas- urements either in 1902 or 1903, and I have seen no mention of the matter in others’ reports. In 1908 I made some measurements by pacing, and determined that the shoreline was still about 200 meters beyond the old strand near the new mouth of the Rabaka, presenting to the sea a low bluff 2 to 4 meters high, at the base of which was an apron, several meters XXXIX—BULL. GEOL. Soc. AM., Vou. 20, 1908 —— es ee 426 E. 0. HOVEY—WALLIBU AND RABAKA GORGES broad, of bombs and other bowlders concentrated by the waves after they had washed out and carried away the finer ash that had been brought down by the torrents and floods of the river. Southward across the broad mouth of the old Rabaka the new shoreline receded slowly, but south of the river the coast was only slightly altered, though there was much fresh ash along the beach as far as Colonarie point and diminishing quantity south of there, varying with the amount of ash deposited upon the land. Colonarie point was nearly at the southern limit on the windward side of the damaging fall of ash. This limit ran irregularly in a general north- westerly direction across the island to and along the ridge bounding the Richmond valley on the southwest. South of this line the new ash did not seriously injure the vegetation, and therefore it remained practically where it fell, and has been washed but slowly to the sea. North of the mouth of the Rabaka the conditions have been entirely different. The windward slopes of the Soufriére as far as Chibarabu point, 6 kilometers from the Rabaka, received a devastating quantity of ash, most of which, however, fell on the catchment basin of the Rabaka. The disposition of this has been discussed already. North and east of this basin the mountain slopes allowed the new ash to be washed rapidly to the sea through several small stream channels, but returning vegetation seems practically to have stopped this process. The gentle slopes of the cultivated plantations have retained practically all of the new material that was deposited on them. From Colonarie point, then, northward at least as far as Sandy bay, just north of Chibarabu point, but particularly from the mouth of the Rabaka northward, vast quantities of new and some old ash have been distributed along the coast by the ocean currents, widening the beach by a few to many meters. It seems likely, however, that the waves and cur- rents will continue their work till the preeruption coastline has been rees- tablished. BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 427-606, PLS. 46-101 FEBRUARY 5, 1910 PALEOGEOGRAPHY OF NORTH AMERICA! BY CHARLES SCHUCHERT (Presented before the Society December 30, 1908) 1 Manuscript received by the Secretary of the Society September 7, 1909. XL—BvLL. Gzou. Soc. AM., Vou. 20, 1908 (427) CONTENTS Page Paaeeta Te UN TRC OE MMP ya eA ire Noa sire he ahiaits (8 Pat oie Ns, a,/0\ oso arated chats Nenon vires oisieh ar a delonaveueuer BIA eaeoe eter 429 ESO TVEEO Ian) UMCOSCOSLAPNY oc. 6 aos. as. bis dus! opsie! © ops duels ol dielw eusue ose. Sere) eisiebers oss 431 er NE MmCOLOTOMCC S562) os fs eucyaves erat arel at averavavartenalonels civahe ‘epee arene jeieleyers Gcavierioy ace 6 431 ESIESINE. - 6:5 0S OO OCHO OPTIC TONE Ia Te cE SUES in Re NPE REIERG Be var 436 Peto SmOImnD ICOZCOSLAPNY 26 os bss oie do sce oie so i Cees Seles os deme Mia. nwe es pieleve 437 Cisse dMOM CO. STHEENOMSS:.) osc) a6 4s. ele Ks) sun, sve ons 0 lee SMe e «cr elere aca oa ode 437 Eel Chali Obl OG ire /ss: she disc! « fare: & «alain are jollalianelke lade eratel e's) oes ler oomabele 6 nrowiials 437 SSO bet C LUO OLOGY Sonat cr eader > aissrexoGusl cue olar sia: breuaiin, Sie mule: Mivvoy Sone Bae akon amie g 437 COE TTS TAN CLOT OSTES fais ocr tapers eee va or o fap ede te clierentnine hiegs ei Suolakee tolae te ehabebalie 437 Commmental Seas are Shallow oo..0 4 b.c.0 8s 2 saeco knee ceareee wee wate 438 HOSsISeInOlcativerOn Exact PIMC)... 22 cielsrsg eis clave © wreck as se eishole 439 emeIISTa CGS MeN eer Wet ais cleus Rane e(otin os Nia ier sires 9) oa elias aueua athe ae asonaibeeniny Ae aceh meee, whl ovale ts 440 WHEGEMUS TAS LAMINA KOISETUOULORS + 5 scoreless ciaciclare) Aleieraie ever ol speius seu cynic Steve 442 OC TEXEL NTSC his II Ae aR ee ARE a a 445 Pare OMG OH CHATNE CHOC) ’ = cuer x ccverene cose ae Sie! ace mk eile os oe eteronare hip label bere Ab wie, ate ude cos 446 ERE cCuroraremmI CMO (8 a csc e! erat) aaa ears cave & evened a tele clicmela coches latewel stiee wityuerape vie 446 “DF SS EIEG 'Suslilu TERS TRL OT Lie epee a etc 2 A a EP ne ti ad OR AAT Continental seas, or negative continental elements...............0.ceee0% 447 imeouMeE Anas: OF POSitive Clements... 2.00.00. ccc eeceueuccecc new vee 464 Pe Msecinenes Ol Ene) SLVANG-NMNE. 2.0.0.2 )2ie 5c \e os sae aie oe 6 ole e eyeiselees aueca oes 475 MiMmMecceneCes ml) EFANS&TECSSIONS. « « acis0 + oo sue @ php areas ours, setieeis shave ee 475 Paleozoic enrergences and Submergences.......6.. 00. ccccs ews cncceen 479 CMC AMOS CUISS TO May si, cesiea chee snchave cate are tetevlets Sle ota soi ra eilvohevene lees el ste a 479 PGI CLEC COMLIMEMbAN SEAS cis o's 1s oo.s.alels cia ses eine d epelielepealeiefit sim a) ace « 480 Sime HNN en COMEIME MA ISEAG C4 so 4. a:¢ arco o/encbolarc sk feee tole lane BEEN er allgy ie acs 480 ACI COMPMIEMEA SCAG E as os. odes 2 e.e cd slerel aie aie a ale aoe UNCNR Ewe 6: ls 480 ArAnSSLeSsime -COMbIMEMPAl MSCASIC..4 < s:c sersisc si cele His oe tues Gore sus se. ok 481 MAME MtT dS Pre WONElOMm per wee Le aitia ) otedale sus 5 ei evepe ce cba oe ns oo Secale’ e \e 482 CeOreiGs PCLlOUd OLEBSY;StCMMe etre aera caics bros sce e e lanene fa Saheiac w bless 482 PCH CHDEEIOMROLUSVGEE IMac orm siete aie G/aloce kid cue cto seta wale Goer 483 Sane Or ours rams ereSsiOMepsisie «arse. aiereue duel che tetedo ie Lictardesesicieual ave 483 HrAnconiat CMmleCrsem Cems criecciccckoere eeuek ke cel eeie Goh as 6 484 428 Page Ozarkie period) or ‘System’... 0.6 aes Clee k ee ee Gea ee 484 Ozarkian transgression (2 oie. aa es ecg olen Reel 484 Shakopee CMergence .. 0 :.\cc jasc wo clare a bielm Greene er elete eee 485 Canadic period. or SyStemi si) 1.5%0.4. 6. ete. cee. eee 485 Beekmantown transgressiom::.. 02. 1). 20/456. seine eee 485 Saint Peter eCMergene@e. a occ ie sso als scree eyelets a.clele eee 485 Ordovicic. period or System... 20.65. heb ce dee ee eee 486 Trenton transgression’ 2.0.0 2.08. on sds 2 les os ole 486 Utica emergenee ces cn cca coe tle a a Soe os lere coke ee 486 Cincinnatie period, or system. 2.0.0)... 602.0.) eee 487 Richmond transgression: 2.0.6...) ge 56 3 de oe 487 Taconic revolution. 2.6... 56 .j6 6.5.06 oale 6 cle 4 oa cue 488 Siluric period or system. 6.15 .055 06. secs cig 0 se eee eee 489 Niagaran, transgression 2... 0.0.6.6 53 6 © «0 «nels er ene eee een Cayugan @Mmergence | ois ose cl os de bes 4 Oe ae 491 Devonic period, or SyStemi nc) os ork Ooo okes oo eee 491 Onondaga’ transgression 2. ..3c00.3 000. cans de eee 491 Chemung eCmergence 2) ..005 6. en aie ein. lee oo eee 492 Mississippie period or system................2 9 1 seein 494 Kern Glen invasion... 0 oes Gece eee ele os ee Sr 494 Keokuk @€MergenGe oo. gcse ced eld ed be eee selene ne 494 Tennesseie period or system... 20.060. see ces ca ene ee eee 495 Saint Louis Invasions... 06.66 6 ee ee « em «oe ee 495 Kaskaskia @Me@PgenCG@ 26 ow cee 8 cee ee wore en ae 495 Pennsylvanic-Permie period or System... .: 2... +. eee 496 Pottsville: transgression... 6. a kc a ce ele 496 Appalachian ‘revolution 0.000.020. 0004.5 5 Jee 497 Summary of emergences and transsressions.. +7. 25.25 see eae 498 Explanation of the tables. ....:3 ose as see 2a winiecie sere 498 Regional- MOVEMENTS oy )e cies. bed alec ie ele eel Sleres gous eee eke eer 500 EMEP SCNEES ee leiley Sena Gla aacalel a Gyaleus iets getelielleligs Meeel elle eloutl Gee 503 Influence of earth shrinkage on the distribution of continental seas. By Joseph Barrell... 2.0. 052. 5.5 0). . 2s eee 506 Transgressions” fs.00 os. oo eele ieee oe 508 Oceanic participation in the transgressions. < 222222 - eel 510 Oscillatory S@€AS 6 eles cokes «ee Sie elles. balers.) vel ee Channa raya bat Oceanic level oc 6 Peis bie ee ieres cle sie Ole Ske p lanee ehetete eee 512 Description of the paleogeographic maps and classification of the Ameri- can geologic formations into periods and eras................sse-e--e-> 513 Paleozoic and Neopaleozoi@.. 2.6 ob ees ee wale es ce 8 oes oleae ene 513 PaTCOZOUC WOR oie). bin oa oe ale ws eeaial ate. bie ls/louiel'el ays ee elevate ates terete ey eee err 516 GeOTPIE PELIOM 2... 6 6k cece elece t,o 0% eieile wl ereital es wie: 61 5)0a)letco) etote ete 516 AGCAGIC’ PELIOR oi. .s.0 5 6 ois e Sale w bias ie acmlale wie foletiaiers ees cial eaetal ee ns 520 Ozarkie of Cambric period. i: ous 25d. occ ee os » oles eee Hee Ordovicie period of authors... 0.000524 5 2. ees eee 524 Canmagie Pemodane secie. .v. MORO e cram nmimua scm ca en dos >. ners 526 - Ordovicic PWEGIOd os6:. jc 5 cs sos) 5 sare olelai es) shelisel suas ol ee (a ope 529 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Cineinna tie 7peniod ie oi: o6!..3 oes ee eee eee tae 530 INTRODUCTION 429 Page INEODAICOZOIE. CRAM pe eae isrere Tee eae te eee Nate cte ete ulayre aye! iCal Gat be) aie ala cyal ane D382 SUUMUFICLOL Onmbawrl CMMerlO deer aarrr cee aie cca aie creel se etelie s)/s)'s' c.3 (eon) Dede IDE VOMICH MCI OM Meee eer ered escrte weisio nrc ce sloubetale e644 s/s 540 VISSTISSIO TEL MPC TUOG eer tert ue ee devote 4 chat ccct onc tial el its che/alie whe ls eieher ee) ce 46 D47 LRETMESSCLCH PC TOM Geter: cree aie pitta ye Celta te (ah ote fae folie) atts alee le doce bautieidel gieliet elena el ¢ Do2 Rennswmly amici Cui PerlO dine ey acitle tale as cbeyey cuore, st etay as este sie, ges silecnr S © aya) DOES Oy ZO CeCe thts re atte ee oy or ls owe nT Sat Cire he duels ada; crate see a ais aaa eum # ed ened 576 ACT AS SIC ano CTO Ce trey aeser va ar awerea are ye) mise, cxteice wi Wiane (eV Orel « elleueins voltalie/o Ne lola late, o3.008 D716 LMA SST Copp CTLOC MR cnsiren ce clckone sean) ifol cr iele eiviicvers tayenar e.ccrecereia. tke hialieloletavens: sty 's 580 GS OMA AMEMTE MOCTIO Cis esas. ce evo sce eich Sie eid arora ehacavel 6 Glave atebene, @hatecate we ictlebe euetele 583 WGRCETEHCHMDC TOM Wie rsteieta a aia fol allel Seorairanel mie eure Guele wl ghe oars wha Gude cal lenst wheel were a8T Maryn Or iNeCOZOIG. (CONOZOLE) OL «.:.12.sSosy< eel esae sis aye Wie este e eleie ena ie D997 MbemMENeAeO LOCH timMe” EADIE 2 c)5/ S56 am sie oa shescier sca g/e aie Que Sie deka sun’eiavevelace fe 600 INTRODUCTION? It is now nearly thirty-eight years since the writer found his first fossil at Cincinnati, Ohio, during the past twenty-four years of which he has de- voted his entire time to invertebrate paleontology and Paleozoic stratigra- phy. His professional service in these sciences had its initiative in associa- tion with E. O. Ulrich, and was continued with James Hall, C. E. Beecher, and Charles D. Walcott. Subsequently nearly all the larger American col- lections of Paleozoic fossils, as well as many European ones, have been examined or studied by him. For eleven years he had charge of the un- rivaled collections assembled through the various government surveys, which are now deposited, together with much other material, in the United States National Museum. It was during these years of paleon- tologie abundance, grand library facilities, and the enthusiasm engen- dered through daily association with eleven paleontologists that he began the investigation of the problem of interprovincial correlations. The greatest stimulus toward determining the provincial value of fossils came in 1894, from reading Suess’s celebrated work “Das Antltz der Erde.” Observations of the kind noted by Suess became sufficiently frequent by the year 1900, so that when Ulrich removed from Newport, Kentucky, to Washington, the inspiration of his presence, together with his detailed knowledge of the older Paleozoic periods, led to the publication in 1902 of “Paleozoic seas and barriers in eastern North America,” this paper being the first joint expression on inter-regional correlations by Ul/tich and Schuchert. From this time on, and especially since his appointment at 2 Teachers and others may obtain of the writer, at cost, copies of the paleogeographic maps as here printed, as well as of two types of blue-prints of the original maps, size 20 by 26 inches; also lantern slides. 430 C. SCHUCHERT——PALEOGEOGRAPHY OF NORTH AMERICA Yale University, the present writer’s efforts have been largely devoted to the paleogeography of North America. Fifty-seven paleogeographic maps have been made and fifty-two are here published, nearly all Amer- ican sources of geologic literature having been ransacked for information. In presenting this work to his collaborators, the writer feels impelled to state that he is fully aware of the imperfection of these maps, but they are now issued for the purpose of furnishing something tangible on which to work. ‘To continue these studies, and thus be enabled to offer later an improved and larger series of maps, is the hope of the writer, who asks the cooperation of all paleontologists and geologists toward this end. While the maps were in process of construction the underlying princi- ples thus brought out were frequently discussed with Professor Barrell, of Yale University, and from time to time the maps themselves were labored over with Ulrich and Stanton. At the Baltimore meeting of the Geo- logical Society of America most of the maps were shown, since which time the seas plotted on them have undergone many a surgical operation at the hands of Canadian and American geologists. During April, 1909, a week was profitably spent in Ottawa, where the maps were much im- proved by suggestions made by the geologists Ami, Ells, Dowling, Mc- Connell, Fletcher, Faribault, McGinnis, Keele, and Lowe, while later two weeks were devoted to the same end by the paleontologists of Washing- ton—Ulrich, Stanton, David White, Knowlton, Dall, Walcott, Arnold, Vaughan, Kindle, Bassler, and Breger—a day being finally given to them by Clarke at Albany, New York. Berry, of Johns Hopkins, also helped. Much information in regard to the geology of Alaska was obtained of Brooks. For other areas direct assistance was had of Ransome and Men- denhall. To all these gentlemen, to Messrs W. H. Twenhofel and J. A. Larsen, and Miss Lucy Peck Bush, of the graduate department of Yale Univer- sity, the writer desires to express his sincere thanks, which are also due to the various geologists who have worked out the geology of the North American continent and whose publications have given valuable aid in the present investigation, though but few of the authors’ names are men- tioned in the text. For the benefit of those persons who may not be familiar with this voluminous literature pertaining to the geology of this continent, the following indispensable catalogues are here cited: Darton: Catalogue and index of contributions to North American geology, 1732-1891. Bulletin 127, U. S. Geological Survey, 1896. Weeks: Bibliography and index of North American geology, paleon- tology, petrology, and mineralogy for 1892-1900. Bulletins 188 and 189, U. 8. Geological Survey, 1902. HISTORY OF PALEOGEOGRAPHY 431 Weeks: Bibliography and index of North American geology, paleon- tology, petrology, and mineralogy for 1901-1905, inclusive. Bulletin 301, U. 8. Geological Survey, 1906. Weeks and Nickles: Bibliography of North American geology for 1906 and 1907. With subject index. Bulletin 372, U. 8S. Geological Survey, 1909. Dowling: General index to the Reports of Progress, Geological Survey of Canada, 1863-1884. Published in 1900. Nicolas: General index to Reports, Geological Survey of Canada, 1885- 1906. Published in 1908. History OF PALEFOGEOGRAPHY DETAILED REFERENCES In his presidential address before the Geological Society of London, in 1881 (page 203), Robert Etheridge introduced the term “paleogeogra- phy,” this being apparently the first time the word was brought into use. However, as the expression is so closely allied in thought with ancient geography, it may have had an earlier origin. Since Canu’s use of the word in 1896, it is frequently seen in print, and is now generally adopted to signify the geography of geologic time. The earliest paleogeographic maps indicating the ancient relation of seas to lands may be attributed to James D. Dana. In the first edition of his “Manual of Geology” (1863), three maps are given showing respec- tively the “Azoic lands and seas of North America” (136), “North America in the Cretaceous period” (489), and “North America in the period of the early Tertiary” (530). In 1865 Heer’s famous book, “Die Urwelt der Schweiz,” appeared at Zurich, and in it were presented four paleogeographic maps of central Kurope during the Jurassic, Cretaceous, and Middle Miocene. These maps are detailed, and agree with modern ones in recognizing that the continental seas are local bodies of water between small land-masses. In 1866 a high grade paleogeographic map made by Goodwin-Austin$® was published in England, and showed the lands and seas during Crag or Pliocene time. Ten years earlier,s however, the same geologist had printed what may be regarded as a paleogeographic map exhibiting the probable lands of western Hurope during Paleozoic and Mesozoic time. This seems to be the first paleogeographic map, but as it treats of no spe- 3 Quarterly Journal of the Geological Society of London, vol. 22, 1866, p. 240. 4Ibidem, vol. 12, 1856, plate 1. 432 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA cific time—the author himself so states—the priority apparently belongs to Dana. In the second (1874) and third (1880) editions of his Manual, Dana’s three maps of 1863 remained practically unchanged, but in the fourth edi- tion (1895) six new and much improved maps are presented. An analysis of these shows that they are not based on a limited time, but are com- posite maps of an entire system; further, that the seas are made to spread over vast portions of the North American continent, where no rocks of the system under consideration are known even at the present day. This idea of “universal oceans” is forcibly brought to one’s atten- tion in Dana’s map of the Siluric—a time, as will be shown later, when not only vast areas of the continent were above the sea, but during which there was also an irregularly progressive submergence followed by a widespread elevation. Moreover, these maps do not take into account the various and distinct contemporaneous faunas, each of which is re- stricted to a limited region. If, as depicted by Dana, the broad Siluric ocean is to be accepted without intermediate land barriers, these faunas should then have a universal expression, which, as paleontologists know, is not the case. However, Dana’s maps bring out clearly his widely known hypothesis of the gradual emergence of the North American continent and the progressive accretion of younger and younger deposits around his great Laurentian V—the nucleus of North America. Only in the most general way can agreement be had with this hypothesis, for it will be seen that the sea transgresses often and widely over the earlier accretions to the North American nucleus. In 1883 the Austrian philosophical paleontologist Neumayr published his celebrated paper “Ueber Klimatische Zonen wahrend der Jura und Kreidezeit,” which includes what is probably the first paleogeographic map of the world. Here, again, no definite time is represented, the map being a composite picture of all the Jurassic. After more than thirteen years of study on the Jurassic ammonites, Neumayr here announced the distinct principle of localized and widely distributed marine faunas that appear to be arranged in homovozoic or parallel belts due probably to zones of different temperature. On the basis of this distribution of marine Jurassic fossils he conceived the great transverse continent of Gondwana— a continent that has since become reduced to the present India, Africa, and South America. He likewise was the first to point out the fact that in all probability during Jurassic time there were climatic or temperature zones very similar in position to the temperate and tropical belts of today, yet no Permic nor Cambric tillites and scratched grounds had then been discovered. HISTORY OF PALEOGEOGRAPHY 433 The Irish geologist Hull’ published three paleogeographic maps of Archean, Siluric, and Carbonic time, showing a great continent in the North Atlantic that furnished the sediments for the Paleozoic formations of western Europe and eastern North America. This he inappropriately ealled Atlantis. It is a striking fact that all paleogeographers dealing with the North Atlantic region have indicated this great transverse land variously known as Laurentia, Arctic, Greenland, Atlantis, North Atlan- tis, Great Northern continent, Nearctis, and Old Red continent. It is the Paleozoic and Mesozoic equivalent of Gondwana, the continent equally extensive in the southern hemisphere. In the three editions of his “Geological studies,” published between 1886 and 1889, Alexander Winchell presented six paleogeographic maps that show far more emerged land, usually as islands, than the maps of Dana; but in these also are indicated the widespread, freely intermingling waters of a vast continental sea which, if really existent, would have pro- duced universal faunas. The first geologist to put forward a series of maps showing the pro- gressive geologic geography of a given area was Jukes-Brown, who in his volume entitled “The building of the British Isles: A study in geograph- ical evolution” (London, 1888) included fifteen such maps. This repre- sents the earhest extended work on ancient geography consistently wrought out on the basis of the distribution and the petrologic character of the geologic formations and their deformations. His principles are not widely different from those of Willis,®° but his point of view is that of an areal geologist who does not attempt to understand the significance of the entombed fossils nor the detailed stratigraphy, but selects out of each system of rocks the widely distributed formations illustrating the growth of the British Isles. His maps show repeated irregular inundations of Great Britain from the east and the gradual disappearance of the western land into the Atlantic. The most important book of reference dealing with paleogeographic maps is undoubtedly Lapparent’s Traité, which has now become the standard work for maps of this kind. In the fourth edition (1900) of this well known treatise are included twenty-two maps of the world on Mercator’s projection, thirty of Europe, twenty-one of France, together with ten taken from the works of other authors. The fifth edition (1906) presents twenty-three maps of the world on a stereographic projection, thirty-four of Europe, twenty-five of France, and ten from other authors. 3 Hull: Royal Dublin Society, 1885. 6 Willis: Journal of Geology, Chicago, vol. 17, 1909. 434 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Arldt* has brought together a vast mass of paleontologic and biologie information, which he has directly applied to the development and con- nections of the ancient continents. In his unique book, “Development of continents and their life,” he reproduces seven paleogeographic maps of the world by Frech and Koken and adds three of his own. “Antlitz der Erde,” the famous book by Suess,’ is of course indispensa- ble in all paleogeographic work, and is now readily accessible in the English translation by Sollas and Sollas. In his interesting and valuable work, “Archhelenis und Archinotis” (1907), Von Ihering discusses the various ancient lands of which South America is composed, and gives a paleogeographic map of the world in Eocene times. In 1896 Canu® brought out an atlas of fifty-seven maps illustrating the ancient seas and lands of France and Belgium. Koken,*° in his well known text book, gives four world maps of Cretacic and Cenozoic times. In 19077 he also published a large and most interesting map of the world in Permic time. Frech!? (1897-1902) has shown six paleogeographic maps of the world during the Paleozoic era. Karpinsky** (1896) gave fourteen maps of European Russia, from the Ordovicic to the Pleistocene, inclusive. Ortmann* discusses the “Theory of Antarctica,” and gives a paleogeographic map of that continent, with its supposed former land connections. D. White*® (1907) enters into an interesting discussion in regard to the climate of Gondwana and the floral distribution obtaining there. Chamberlin and Salisbury, in their “Geology” (1906), brought out — eighteen North American maps of great value because of the careful plot- ting of surface outcrops and indications of the probable extent of the seas. These maps have been of considerable service in the present work. Regarding the fifteen maps shown at the Baltimore meeting of the Geo- logical Society of America, Willis?® is publishing them while this paper is printing. These North American paleogeographic maps are excellent as far 7 Arldt: Die Entwicklung der Kontinente und Ihrer Lebewelt, 1907. § Suess: Antlitz der Erde, I, Abt. 1, 1883, 2, 1885; II, 1888; III, 1901; If Abt 2; 1909. The first two volumes translated into English by Sollas and Sollas, 1904 and 1906. 2Canu: Essai de Paléogéographie. Paris, 1896, text and atlas. 10 Koken: Die Vorwelt und ihre Entwickelungsgeschichte, 1893. 1 Koken: N. Jahrb. Min. Geol. Pal., Festband, 1907, pp. 446-546. 144Frech: Lethea geognostica, 1897-1902. 13 Karpinsky: Bull. l’Acad. Imp. des Sci., St. Pétersbourg, 1894. Also Ann. Géog- raphie, Paris, 1896, pp. 179-192. 14 Ortmann: Princeton University Expedition to Patagonia, vol. IV, 1902, pp. 310-324. 1s White: Journal of Geology, Chicago, vol. 15, 190T. 16 Willis: Ibidem, vol. 17, 1909. HISTORY OF PALEOGEOGRAPHY 435 as they go, but they are too synthetic—that is, as a rule they embrace too much time, and hence do not bring out the oscillatory nature of the conti- nental seas. Willis concedes the validity of the criticism “that each indi- vidual map covers so long a period of time and such diverse conditions that they do not truly represent any special geographic phase of the conti- nent” (p. 204). These maps were made on the following basis: “A certain period having been selected as that which should be mapped, the epicontinental strata pertaining to that time interval have been delineated. The phenomena of sedimentation and erosion have been correlated, with a view to determining the sources of sediment and topographic conditions of land areas, and from these data the probable positions of lands have been more or less definitely inferred. Thus, certain areas within the continental margin are distinguished as land or sea, and these areas may be defined as separate bodies or connected according to inferences based upon isolated occurrences or upon later effects of erosion. “It is assumed that the great oceanic basins and such deeps as the Gulf of Mexico and the Caribbean have been permanent features of the earth’s surface at least since some time in the pre-Cambrian” (page 208). These principles have also governed the present writer in the following investigation. He has likewise been able to unearth a vast amount of paleontologic knowledge buried in American geologic literature, and dur- ing the past thirty years has gained wide experience in the field and the laboratory. The results thus attained have been freely discussed with many men, geologists as well as paleontologists, and the writer believes that by “selecting narrower time limits and more precise correlations than have been attempted” by Willis, he has taken at least “one of the steps in the advancement of knowledge” (Willis, 1909, page 204). Walcott*” has a “Hypothetical map of the North American continent at the beginning of Lower Cambrian time.” In the same year'® appeared another paleogeographic map portraying “the beginning of Ordovician time.” ‘Three very small maps, also representing Lower, Middle, and Upper Cambric times in North America and ascribed to Walcott, may be found in Lapparent’s Traité. Walcott’® has likewise brought out a valua- ble “Hypothetical map to illustrate the areas of the Cordilleran, Missis- sippian and Appalachian seas.” lLogan?° has given an excellent map indi- cating the outlines of the late Jurassic continental sea, with North Pacific connections. As this sea is an independent one, it is named by the present writer Logan sea. 17 Walcott: Bull. U. S. Geological Survey, no. 81, 1891, plate 3. 18 Walcott: Twelfth Ann. Rep. U. S. Geological Survey, 1891, plate 45. 19 Walcott: Proc. Amer. Assoc. Adv. Sci., vol. 42, 1894. 20 Logan: Journal of Geology, Chicago, 1900, p. 245. 436 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Berkey** has given two maps showing the position of Mississippian sea during “mid-Saint Peter time” and at the “close of Saint Peter time.” Grabau** shows one map of Cambric and four maps of Ordovicic time in North America. G. F. Matthew** portrays two maps—one of Lower Hu- ronian, the other of Siluric time. W. D. Matthew? presents six good Tertiary paleogeographic maps of the world. Schuchert?® published two Middle Devonic maps of eastern United States, and in 1908?° presented three paleogeographic maps of the North American Devonic. Scott brought out eight paleogeographic maps of North America in his “An Introduction to Geology,” 1907. Weller?’ indicated on two maps the prob- able shorelines within the United States of the latest Devonic and Osage of Mississippic time. ‘The same paleontologist?* published two excellent maps of the American Siluric shorelines and the Arctic path for these European faunas. Williams® presents a “chart showing the approximate position of the Devonian intercontinental sea.” Veatch®® exhibits ten maps of the land and water areas in the south-central United States dur- ing Cretacic and Tertiary times. Clarke*! gives two Lower Devonic maps. of New York. RESUME By tabulating these maps, it will be seen that since 1863 no less than 306 different paleogeographic maps have been published, of which 151 relate more or less directly to North America. These maps are as yet highly hypothetical, this being particularly true of world maps. The changes wrought in these maps are fundamental. Instead of the “universal oceans” of the older maps, modern ones show much smaller and more local seas, separated from one another by land barriers. Also may be noted the irregular emergence of local lands that are repeatedly submerged, the general tendency, however, being toward more stable conti- nents and oceanic basins. The local seas, first mapped by Heer, may be seen to best advantage in Lapparent’s most valuable Traité. Very few of the maps, however, as yet clearly differentiate between marine and conti- nental deposits, and by the inclusion of both as marine deposits the con- 21 Berkey: Bull. Geological Society of America, vol. 17, 1906, pp. 248-249. 22 Grabau: Journal of Geology, Chicago, vol. 17, 1909. 2G. F. Matthew: Bull. Natural History Society of New Brunswick, vol. 6, 1908. 24W. D. Matthew: Bull. American Museum of Natural History, vol. 22, 1906.. 2> Schuchert : American Geologist, 1903. 26 Schuchert in Eastman, Iowa Geological Survey, Ann. Rep., vol. 18, 1908. 27 Weller: Journal of Geology, Chicago, vol. 6, 1898, pp. 307-308. 28 Weller: Ibidem, 1898, pp. 697, 699. 23 Williams: American Journal of Science, vol. 3, 1897, p. 395. 30 Veatch: Professional Paper, no. 46, U. S. Geological Survey, 1906. 21 Clarke: Memoir no. 9, New York State Museum, 1908, pp. 8-9. = METHODS OF PALEOGEOGRAPHY A37 tinental seas are not only enlarged, but seas are even brought into existence where none whatever occurred. METHODS OF PALEOGEOGRAPHY CLASSIFICATION OF METHODS The methods or principles for determining the relation of ancient seas and lands are four in number: (1) The Paleontologic, (2) the Areal- Geologic, (3) the Petrologic, and (4) the Structural or Diastrophic. PALEONTOLOGIC METHOD Basis of chronology.—The primary basis for a geologic chronology is furnished by the organic remains entombed in the stratified rocks. All methods for the exact determination of geologic time are at present de- pendent upon paleontology, yet it is not to be denied that locally other means than the paleontologic may become of prime importance. Continental deposits —There is as yet no established petrologic method whereby marine deposits can be distinguished from those of fluviatile or lacustrine waters. Fossils, therefore, are of vital importance in determin- ing whether a sedimentary deposit (1) is derived from waters of the land deposited on the land—that is, a continental deposit—or (2) is of terres- trial origin, but laid down in marine waters. The physical nature alone of some formations renders their fresh-water or eolian origin fairly cer- tain. When with these characters are combined the lessons to be learned from the entombed fossils, then the evidence is convincing. The Triassic sandstone of the Connecticut valley consists of deposits which have been termed estuarine and fluviatile. They are better exposed and more extensively quarried in Connecticut than any other formation, and have been explored by geologists and paleontologists for more than a century, but not a trace of a marine animal has thus far been discovered. Evidence equally as strong was available twenty years ago, yet Dana taught that these sandstones were laid down in an estuary like that of the bay of Fundy. If this were true, marine fossils would have often been brought to light. On the other hand, indications of land plants and land animals are frequently met with, the most abundant being the footprints, or autogrammes, as Newberry called them, of quadrupedal, but mainly of bipedal, terrestrial reptiles. After being persistently collected, these tracks were described, first by E. Hitchcock, later by C. H. Hitchcock, while recently this subject has been restudied by Professor R. S. Lull,*? who has determined 40 genera and 92 species. These impressions are all 32 Tull: Memoir of the Boston Society of Natural History, vol. 5, 1904, pp. 461-557. 438 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA autogrammes of vertebrates living on the land. Of dinosaurs, there are certainly 17 species of Theropoda, with 18 of Predentata, to which may be added 27 other species that are probable representatives of this order. Of the bipedal carnivorous dinosaurs, three skeletons have been found (Anchi- saurus colurus, A. solus, and Ammosaurus major) ; also, in addition to Belodon, two other crocodilian skeletons of quadrupedal land reptiles (Stegomus longipes and S. arcuatus). In the black shales between the extensive trap sheets occur many ferns, equisitales, cycads, and conifers, besides ganoid fishes and the larva of a neuropterous insect—an assem- blage that can be interpreted only as that of inland fresh waters. None but animals and plants that inhabit the land are here seen, and when these are considered in connection with the exceedingly common sun-cracked layers of mud, less frequent raindrop impressions, local accumulations of semi-rounded boulders, and the nearly constant lens-shaped bedding of the imperfectly assorted sands and conglomerates between the muddier layers of wider areal extent, the evidence is positive that the Newark series is fluviatile in nature and must be eliminated from marine deposits and Triassic seas. The writer has purposely dwelt at length on the Newark formations, because similar beds are found at many horizons, and until recently these have been regarded as of sea deposition. ‘They must be eliminated from marine deposits, however, and referred to the land, and will thus at times very decidedly affect paleogeography. When continental deposits alter- nate with marine horizons, as is especially the case during Pennsylvanic time, such formations will naturally be mapped as marine. For a full discussion of the areas of deposition and the internal structure of conti- nental deposits, see Barrell.** Continental seas are shallow.—lIt is very probable that a majority of the periodic inundations of the North American continent resulted in very shallow seas, perhaps rarely exceeding from 200 to 300 feet in depth. In the discussion on later pages of this article, it is held that the continent is a horst, that the great medial region remained practically unmoved, while the margins were often folded and elevated. ‘The sea periodically flowed over this medial land—in fact, was elevated over it, owing to the detrital materials unloaded into the oceanic areas, thus filling them and causing them to spill over on to the lands. Along the western shorelines of Appalachia, gomallsmenesce. sandstones, and coarse muds bearing ripple-marks are constantly met with, while dur- ———— 33 Barrell: Journal of Geology, Chicago, vol. 14, 1906, pp. 316-356, 430-457, 524-568. Ibidem, vol. 16, 1908, pp. 159-190, 255-296, 363-384. Bull. Geological Society of Amer- ica, vol. 18, 1907, pp. 449-476. METHODS OF PALEOGEOGRAPHY 439 ing periods of calcareous deposition there is much evidence of shrinkage cracks on extensive mud flats that have been subjected to periodic inunda- tions of calcareous material nearly devoid of life. These Paleozoic shores. of Appalachia were not unlike the coral tidal flats of present Antillia. In the New York basin, most of the later Paleozoic deposits are those of estuaries, for the material 1s mainly sands and muds practically lacking in marine life. Here and there occur land plants, Old Red fishes, and occasionally fresh-water bivalves. Often the sands are red, oxidized, the estuaries of extensive rivers dried out by the sun and air. In the Ohio basin, but more particularly in the Indiana basin, where the adjacent lands were very low, more often occur similar widespread beds indicative of shallow seas. Such are the thin bedded hmestones in alternation with shales, dolomites, oolites, and calcareous shales. Here may also be seen ripple-marks and shrinkage or sun-cracks. Along Appalachia and Lau- rentia are occasionally found salt and gypsum horizons, while in the late Pennsylvanic seas of Oklahoma occur alternations of red shales with thick ‘beds of gypsum. The intraformational conglomerates further point to shallow agitated seas. The superficial depth of the continental seas is also reflected in the end- less formational names, based on petrologic change, which have been pro- posed by the areal geologists. For further discussion of this subject, see the paper by Ulrich elsewhere in this volume. Fossils indicative of exact tume.—Most paleontologists are now aware that fossils can be relied upon to determine not only the broader units of time, but horizons of considerable areal extent, with but a few feet of thickness as well. Elsewhere in this volume Ulrich introduces remarkable examples of thin horizons that may be identified by a few fossils scattered over vast regions. This clearly indicates the increase in paleontologic knowledge since the days of Strata Smith’s teachings, and today in Amer- ica stratigraphic results are more easily attained because of the wide ex- tent of successive undisturbed formations. Geological faunas within given provinces practically appear instantaneously, and intercontinental correla- tions based on faunule identities—that is, a combination of several spe- cies, in most cases, will probably not be out of synchrony more than from 10 to 20 feet. The evidence for these statements is discussed elsewhere by Ulrich. It is now not always necessary to possess large collections of fine mate- rial in order to make correlations or to identify horizons of limited zones, a single fossil often being sufficient for this purpose. Brachiopoda and Bryozoa are usually to be found in the Paleozoic and are the finest hori- zon markers. In the Cincinnati’series, Catazyga headi determines a zone 440 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA in the Lower Richmond formation never more than one foot thick. C. erratica is always diagnostic of the eastern Lorraine. Triplecia ortont is restricted to a limestone zone, never more than 25 feet in thickness, ex- tending from Oklahoma to Ohio, while a closely related species occurs in a similar zone on the island of Anticosti in the Saint Lawrence gulf. The higher Clinton, from Anticosti to Alabama, may be determined by a single brachiopod, Anoplotheca hemispherica, which also identifies a very similar horizon in northwestern Europe. Rhynchotrema capax in two varieties defines the Richmond formation from El Paso, Texas, to Manitoba, and from the Big Horn mountains to Ohio, and even to Anticosti. Spirifer hungerfordi denotes the Upper Devonic throughout western America, from the Arctic to Bisbee, Arizona, and in Asia and Russia as well. These are not exceptional cases, and many more can be cited. When fossils are carefully collected from bed to bed, it is nearly always found that certain combinations of species called fawnules may be depended upon to indicate unvarying zonal or time values within a subprovince. Sometimes the — latter is of very wide extent, as in the case of the Upper Richmond forma- tion just mentioned, while in other cases they are greatly restricted. As a rule, the more common species can not be relied upon for the determina- tion of limited horizons, especially the ubiquitous plastic forms among brachiopods. For instance, Atrypa reticularis, Leptena rhomboidalis, Dalmanella testudinaria, Plectambonites sericeus, Rafinesquina alternata, Pentamerus oblongus, etcetera, have little value for interprovincial corre- lation, and none at all when loosely identified, as is the almost universal practice among paleontologists. Correlation between provinces is far more difficult, but when large col- lections are at hand the general faunal facies, together with a few iden- tical or closely related species, will usually enable a paleontologist to fix upon a fairly definite time. Exact correlation that may be proved be- comes impossible only in newly discovered areas, as is the case at present for Alaska. Even there, however, the faunas are now taking on deter- minable provincial relationship with those farther south. Barriers.—In the United States there. are often two or more provincial faunas of the same geologic age, apparently having geographically contin- uous strata that are wholly different, there being but few species common to them. As an example may be cited the Middle Devonic coral faunas in Kentucky, Indiana, Ohio, New York, Ontario, and Hudson bay. Con- trasting this well known assemblage with the less abundant coral repre- sentation in Iowa and Missouri and in the entire country west to the Pacific, it is seen that while there is a time expression common to both provinces, there are practically no identical species. ‘The eastern assem- BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 46 FIGURE 1.—QUARRY OF BENNETT CEMENT AND QUARRY COMPANY, BUFFALO, NEW YORK Upper 8 feet Onondaga limestone (Lower Middle Devonic). resting on eroded Cobbleskill (Manlius of Siluric). which in turn rests disconformably on the Bertie waterlime (top of Salina of Siluric) having Eurypterus. FIGURE 2.—BEAR GRASS QUARRIES, LOUISVILLE, KENTUCKY The Onondaga coral reef rests disconformably on the Louisville coral reef LIMESTONE QUARRIES NEAR BUFFALO, NEW YORK, AND LOUISVILLE, KENTUCKY METHODS OF PALEOGEOGRAPHY 44] blage is American in type, while the western has the widely distributed Euro-Asiatic aspect. What is it that keeps these faunas distinct, when at times the formations in which they occur approach one another in type to within a distance of 50 miles, or even less? At present there are no visible lands separating them, nor even easily discernible geologic struc- tures indicating former land barriers. Those who have studied their relationships hold that a land barrier did exist—the Kankakee axis— which kept apart these distinct provincial faunas. Many similar cases are indicated on the maps here presented. It is known that the forma- tions thin out in places and are petrologically different on the two sides of ‘such barriers. As long as these physical conditions are maintained the faunas remain distinct, but when the deposits spread far and wide the faunas, through blending, lose their individuality. For the benefit of those not believing in land barriers unless they can see decided unconformities against which two given seas deposited their similar or dissimilar sediments, a few photographs will be here introduced, showing conformable strata with wholly unrelated superposed faunas. In the Bennett quarries at Buffalo, New York (plate 46, figure 1), in a little cliff less than 20 feet high, may be seen the Middle Devonie Onon- ‘daga coral limestone reposing upon a slightly irregular surface of the Cobleskill-Siluric. Elsewhere, between these two deposits, the Manhius- Silurie and all the Lower Devonic were laid down. Such sections are by no means rare. In western Tennessee, at Newsom, is a quarry face about 75 feet high (plate 47), at the top of which occurs the widespread Ohio black shale, here representing the Lower Mississippic. With sharp petro- logic change, but otherwise without apparent break, this stratum rests upon a zone about six feet thick, bearing the impress of Onondaga time, for in this horizon has been found the well known pentremite Nuwcleo- crinus vernewili. Therefore here is absent all the Hamilton, which at Louisville is a limestone with a thickness of 28 feet, and in central New York is 500 feet in depth (shales). In the Tennessee region under ‘discussion, below this thin limestone is another break, for the Onondaga rests on the Louisville-Siluric. Between these two beds, therefore, all the Salina, Manlius, and the entire Lower Devonic are missing. Fifty miles to the west, however, most of the Lower Devonic has appeared between these Siluric and Middle Devonic formations. The disconform- ity last mentioned is one of vast extent, and may again be well seen at Louisville, Kentucky (plate 46, figure 2), in the large quarries along Bear Grass creek, where the same relation exists as at Newsom, Tennes- see; in both instances the Onondaga Middle Devonic coral reef reposes upon the Louisville-Siluric coral reef. This extensive land interval, 442 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA which is represented in the photograph by a horizontal line, can be traced: through these quarries for half a mile, yet the two deposits can not be readily separated by any other means than the entombed fossils. ‘Such disconformities are numerous and are of general occurrence in the central. portion of the United States and Canada, where they have led to the dis- covery of various land barriers so necessary to a proper interpretation of faunal provinces. It has been assumed by some geologists that where such disconformities occur the sea has been continuous and has failed to deposit sediments, or has even scoured away parts of the sea-bed, as is the case with the present gulf current when it is forced between narrow passages like that between Florida and the Bahamas. The question may be asked of those making this assumption: Why is it that a sea which has not laid down strata for thousands or perhaps hundreds of thousands of years suddenly begins to- deposit sediments? In this connection it should be noted that during Louisville time a clear sea was the agent for the precipitation of coral- reef limestone, and that very much later, in Onondaga time, it was fol-- lowed by another sea with identical physical characters. During the in- terval, if the sea were present, it did not accumulate material nor remove an appreciable thickness of the limestone by leaching. On the other hand, scouring of the sea-bottom is known only where the Gulf stream flows. swiftly, a condition which is exceptional in existing seas. Neither can it be admitted that the land interval was less in time than the fossils indicate, nor that extensive sheets of limestone have suffered erosion. If the latter were true, outhers of these missing horizons would be found, for the land was so low that the wearing away could not have removed them completely over hundreds of miles of extent. Since late Ordovicic time the Cincinnati region has been above the sea, yet it has lost less than 300 feet by erosion, and probably the greater part of that has been taken away since the Pleistocene elevation. It is possible, however, that a thin Mississippic formation may have covered the Cincinnati area ; but in any event less than 400 feet have been eroded since the close of the Ordovicie. Currents as fauna distributors—The statement has been made that it is not necessary to assume the presence of land barriers to have distinct faunas in a wide spread supposedly continuous sea, but that such will be kept separate and distinct by currents having decided differences in tem- perature. In other words, two definite faunas may exist side by side in the same marine waters, this condition being certainly in force at present in the Atlantic ocean off the coast of America. On the continental shelf, as far south as cape Hatteras, lives the fauna of the cooler waters due to BULL. GEOL. SOC. AM. VOIEs 20; W085 Tks arr QUARRY .FACE AT NEWSOM, TENNESSEE Upper beds are the Ohio black shale (Lower Mississippic), resting disconformably on 6 feet of Onondaga limestone (Lower Middle Devonic), which in turn lies disconformably on the Louisville (Middle Siluric). Ee - - oe sz ee re Se = METHODS OF PALEOGEOGRAPHY 443 the Arctic currents that flow south along this region. Impinging against the outer edge of the continental shelf in the deeper water occurs the warm Gulf stream, and yet the two faunas are quite distinct to within about 10 miles of each other. All along the present shores, where there are currents of cold and warm water, it is the rule to find distinct faunas on each side of prominent land promontories. Furthermore, many of the cold-water species of the northern Atlantic follow the cold water south of cape Hatteras into the deeps beneath the Gulf stream. While the truth of these statements is not to be denied, yet in dealing with existing life as the basis for interpreting geologic faunas one must not lose sight of the important fact that the marine waters of today are those of a glacial climate. During most of geologic time the temperature of the ocean was far more even than at present, with no such variations as now oceur in the northern Atlantic from 72 degrees Fahrenheit at the surface to 33 degrees Fahrenheit or even less in the abyss. During the Ordoviciec, Siluric, and Devonie there were only slight differences in tem- perature, and these variations were no doubt due to latitude. That during these times the marine waters had a nearly equable temperature is seen in the very similar Mohawkian faunas of Tennessee, New Jersey, Minnesota, and Baffin Land; reef corals of Devonic age occur in abundance not only im Kentucky and Indiana, but almost equally so in Alaska, while certain of the Siluric faunas of the interior region are undoubtedly derived from those of northern Europe, which migrated to America by way of north Greenland. Finally, attention may be directed to the fact that in Miocene times magnolias flourished in Greenland. The region of the strait of Gibraltar is a good example of an almost complete land barrier that is ineffectual as a faunal barrier because of a small opening in it. The Mediterranean entrance into the Atlantic is only 9 miles in width, yet hundreds of warm, shallow-water species have spread north along the coasts of Spain, Portugal, France, and even to the south shore of England. Some of the species have distributed themselves along this shoreline fully 1,500 miles, measured in a straight line. On the other hand, the deep-sea faunas on each side of this submerged barrier at Gibraltar do not spread, owing to the great difference in temperature. From this it is seen that however small an opening may exist between two bodies of water with nearly the same temperature (Atlantic, 72 degrees : Mediterranean, 75 degrees), the two faunas will intermigrate in spite of the further fact in the present instance that the Atlantic is less saline and becomes progressively cooler toward England. Tt can be said with certainty that in marine continuous waters, either warm or cold, but of fairly equable temperature throughout the year, the XLI-—BULL. GEOL. Soc. AM., VOL. 20, 1908 ————— ee ~~ ee a 444 C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA faunas become very widespread. As examples may be cited the Antillian shallow-water fauna living within 60 fathoms, which has spread to Per- nambuco, Brazil, Florida, and Bermuda, and a few species even to cape Hatteras. The same is true in the Pacific ocean from north Peru to southern California, and these are distances representing 3,000 miles or more. In this wide distribution undoubtedly the currents have greatly facilitated migration and the blending of faunal elements, yet a far greater factor 1s an equable oceanic temperature throughout the year. Sunilar dispersion may be noted in a: case of single species: for stance, that of Purpura lapillus. “This group is abundant in the North Atlantic, and has made its way through the Boreal region into the Pacific, being modified into several geographic races. On the western coast of North America, where there are no sudden changes in the temperature of the sea water, this group has made its way as far south as Margarita Bay. in latitude 24° N.. mean temperature 23° C. On the Asiatic side it has made its way through Bering Sea down the shores of Kamschatka with the cold water, but has been stopped by the sudden change of temperature at Hakodadi, latitude 41° N., Japan, mean temperature 11° C., where the warm Japan current meets the cold current from Bering Sea. That this is not an accident of distribution is shown by the fact that the group of Purpura lapillus has, in the Atlantic, a similar distribution, and for the same reasons. On the African side it reaches latitude 32° N., mean temperature 19° C., and on the American side it is barred back by the sudden change of temperature at lat. 42° N., mean temperature 11° C. There can be no doubt that the temperature, or rather evenness of change of temperature, controls the distribution of Puwr- pura lapillus now” (J. P. Smith, von Koenen, Festschrift, 1907: 415). During periods of greatest inundation in warm climates, as those of the Mohawkian and the Niagaran of the Mississippian province and of the Middle Devonic of the Euro-Asiatic province, there are in America almost universal faunas. This is also in conformity with the postulate that dur- ing times of extensive inundation the land barriers are least effective. That the physical conditions of the Paleozoic can not be altogether deter- mined by the character of the present Atlantic may be proved by the tabu- lations of shallow-water life presented by Doetor Dall. He states that in the existing “cool temperate zone,” where the minimum winter tempera- ture of the water is not below 40 degrees Fahrenheit, in both the North Atlantic and the Pacific ocean, and at any station where good collections have been made, there live on the average 407 shell-bearing molluscan species. In the “warm temperate zone,” having a temperature of between 60 degrees and 70 degrees Fahrenheit, the average is 483 species, while in the tropical zone the average is 629 species. It is also stated that these figures compare favorably with the number of species representing Ter- tiary faunas, but that with the latter the tendency is toward even larger METHODS OF PALEOGEOGRAPHY 445 numbers, because the collecting of fossils 1s carried on under conditions far superior to those in force today when dredging for existing faunas. On comparing these figures with those for the Cincinnati region, proba- bly the best known Paleozoic locality in America, it will be found that from the Cincinnati series, which has a maximum thickness of about 850 feet, there have been gathered about 1,100 species, if the undescribed forms represented in the various collections are included. This series is now divided into 14 zones, each having an average thickness of about 60 feet, thus giving a fauna of about 80 species for each zone—a figure far below the average in the faunas of the present oceans, the smallest num- ber being 407 species. The Richmond formation is the most fossiliferous, with an estimated number of 500 species; as there are 6 zones in this for- mation, this will give but 83 species to each subdivision, the latter hav- ing, according to Cumings, an average thickness of 60 feet. Further, in the Cincinnati faunas all the known fossils are included, not the mol- luses alone. Along the Atlantic shore, from the Rio Grande to the Arctic region, Dall lists 1,364 species of shelled molluscs within the 100-fathom zone. ‘This is a far larger representation, probably four times greater, than that of the entire fauna of the American Trenton which has equal latitudinal extent. Other and similar evidence could be offered, but it will suffice to close this subject by adding that no paleontologist who has looked into the present dispersal of faunas understands how currents of similar tempera- ture can keep shallow-water faunas from intermingling. It was the cur- rents and the equable temperature of the ancient seas that facilitated the migration of the shallow-water life, and this is especially true of the larval and adult animals living near the surface of the sea. Land barriers and shallow-sea marshes, together with decided temperature and saline differ- ences in the water, are the effective causes preventing the distribution of faunas. ‘Temperature and saline barriers, however, are comparatively seldom effective in geologic time, but the land barriers are continually occasioning the localization of faunas, and by their breaking down permit the intermigration of the localized biota. The entire subject of sea- currents should not be used to explain faunal differences, but for the present should be laid aside. ‘The first need is to establish paleogeogra- phy, a result which has as yet not been attained. Conclusions.—In making the maps herewith presented the greatest stress has been laid upon the distribution of faunas, both as to time and space, as known to paleontologists. When synchronous faunas were found to be different and a lapse of connecting strata occurred, these facts were interpreted as meaning that a land barrier more or less complete kept the 446 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA faunas apart. It is fully realized that in the course of time it may be shown that these maps err on the side of too much restfiction of the conti- nental seas. It was thought, however, that by the present method of representation more certain progress would be attained than by assuming universal continental synthetic seas, which some paleontologists believe have not led to a proper understanding of the periodic encroachment of the oceans on the land. An analysis of fossil faunas indicates that from the earliest Paleozoic times there have been three permanent oceanic realms that have furnished hfe to the continental seas of North America. In the order of their im- portance these are: (1) The Gulf of Mexico mediterranean, (2) the Pa- cific, (3) the Arctic and the Atlantic. The faunas of the North Atlantic as a rule are restricted to Acadia and to the eastern portion of the Appa- lachian mountains, yet they frequently spread across these folds and mix with the life of the other regions. Those of the Pacific have a far wider range, and often occur as far east as Appalachia. ‘The faunas from the Gulf or Mexican mediterranean are at times clearly tinged with an Atlan- tic facies, but oftener are more of the southern than of the northern European type, while at other times they are without doubt from the ~ South American realm by way of the Pacific. AREAL-GEOLOGIC METHOD Having ascertained the nature of a fauna and its stratigraphic position, the next point of greatest value is the geographic distribution of the for- mation. Here geologic maps are of the highest importance, especially those that give lists of the local faunas. In this connection the Folios of the United States Geological Survey were most helpful, but all maps issued by the more prominent national and state surveys were scanned for information. The recently published International Geologic Map was likewise found to be very useful, particularly so for outlying regions of the North American continent. PETROLOGIC METHOD Marine conglomerates unmistakably indicate proximity to land, and are therefore of great value in paleogeography. Marine sandstones are also good indicators for shore conditions, shallow seas, and nearness to land, but are not so reliable as the conglomerates. In the interior region of the continental seas, however, sandstones are of rare occurrence. Mud de- posits point rather to shallow seas, and black shales are thought to denote closed or stagnant arms of the sea, variably foul at the bottom, as in the Black sea of Russia. Such black shale deposits are the Utica, Genesee, BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 48 IND | \ ————=— aay \ Li SS PP e io a PC eet h ee Ray = SS —————— ——— Sa] ee SE LZ NORTH AMERICAN Fae ——e PALEOGEOGRAPHY ee oe eRnam t — re ee ee By CHARLES SCHUCHERT, 1909 SCALE 100 SO 100. 200 300 400 500 600 STATUTE AIL CONTINENTAL SEAS OF PALEOZOIC TIME METHODS OF PALEOGEOGRAPHY 447 Chattanooga, etcetera, the known faunas of which are of the nekton and plankton type. Asa rule, limestones are indicative of seas of wider extent among low lands during times of moist and warmer temperature, while dolomites mark about the same conditions, but in shallower, evaporating seas. Oolites are formed in the littoral region of seas between tides where the lime salts accrete about a nucleus due to its repeated wetting and drying, and otherwise. The interpretation thus given the various kinds of sediments has been applied in the construction of the present maps, but not with the same eare as that given the faunas and the areal geology. Volcanoes and vol- canie material have also been considered, but information regarding these has been plotted in only a few of the more striking times and areas of eruption. ‘The positions of these are shown by asterisks. DIASTROPHIC METHOD Having ascertained the essential periods of emergence and transgression by the faunal method, the diastrophic principle was then used to fix the major time divisions. ‘Taken by itself, the latter method is beheved to be nearly as unreliable, where permanent results are concerned, as the petrologic method. In fact, the principle of diastrophism can rarely be used before taking the fossil evidence into account, for it is the latter that fixes and determines physical events. Diastrophism, however, is of much value in paleogeography, but it must follow, not precede, the evidence furnished by the fossils. CONTINENTAL SEAS, OR NEGATIVE CONTINENTAL HLEMENTS (See map, plate 48) All the Paleozoic seas now engaging the attention of American stratig- raphers are of the “continental” type—that is, their deposits have been furnished by shallow seas within “great continental basins.” This funda- mental generalization was first announced by Dana in 1856,°4 was repeated in 1863,°° and was clearly defined in 1874.°° The later term—“epicon- tinental seas’—of Chamberlin and Salisbury*’ has the identical meaning of continental seas. The “Interior Continental region” is subdivided by Dana as follows: “(1) The Hastern interior east of the Cincinnati uplift; (2) the Central 34 Dana: American Journal of Science, vol. 22, 1856, pp. 335-349. 3° Dana: Manual of Geology, 18638. 26 Dana: Ibidem, second ed., 1874, pp. 145-146. Also Bull. Geological Society of America, vol. 1, 1890, p. 41. Manual of Geology, fourth ed., 1895, p. 461. * Chamberlin and Salisbury : Geology, vol. 1, 1904, p. 11. 44§ C, SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA interior or Mississippi basin, and (3) the Western interior or that of the Eastern Rocky Mountain slope” (1890: 41). These broad:-divisions still hold good and with slight modification are adopted by the writer, the shorter names applied by later stratigraphers, chiefly by Walcott,** being employed. The “eastern interior sea” will be restricted to Dana’s original definition—that is, to the great Appalachian syncline east of Alleghania and Tennesseia and west of Appalachia; for this area, Appalachian sea will be used instead of Dana’s original name, “Appalachian region.” “The central interior or Mississippi basin” of Dana includes the various local basins on either side of the Cincinnati axis, bounded on the east by Alleghania and on the west by Missouria, Llano, Siouxia, and Wiscon- sia. ‘To this sea Walcott has given the name “Mississippian sea,” follow- ing Dana’s earlier determination. “The western interior sea’ Walcott has called “Cordilleran sea,” while “the eastern border basin or region” of Dana (1874: 146) is here changed to Saint Lawrence sea. These bodies of water and others to be named in the following pages are distinct faunal provinces whose successive biota are received from those great perpetual realms of marine life—the Pacific, Atlantic, and Arctic oceans. They are the “negative elements” of Willis,?® yet as the oceanic areas are the true. negative elements the writer has designated these seas as negative continental elements. They have been defined by Willis as follows: “By contrast with the positive elements of the continent which are recognized by absence of sediments and preponderance of un- conformities, the negative elements are distinguished by the sediments which bury them.” According to the derivation of their faunas, these various elements or seas may be grouped as follows: Seas with Atlantic or Poseidon life-——Primarily (1) Saint Lawrence, (2) Potomac embayment; secondarily (1) Appalachian, (2) Mississip- pian, and (3) Hudson. By inference, Suwanee strait. Seas with Mexico-Caribbean life-—Primarily (1) Gulf of Mexico over- lap, (2) Coloradoan, and (3) Mississippian; secondarily, Appalachian. By inference, Sea of Tehuantepec. Seas with Pacific life-—Primarily (1) Cordilleran, (2) Sonoran, (3) Logan, (4) Californian, and (5) Vancouverian; secondarily, Alaskan. At times primarily, but as a rule with slight Pacific incursions, Missis- sipplan. Seas with Arctic ife-——Primarily (1) Hudson, and (2) Alaskan; sec- ondarily, (1) Cordilleran, (2) Coloradoan, and (3) Mississippian. 38 Walcott: Proc. American Association for the Advancement of Science, vol. 42, 1894, pp. 129-169. 39 Willis: Bull. Geological Society of America, vol. 18, 1907, p. 398. NEGATIVE CONTINENTAL ELEMENTS 449 The foregoing arrangement of these seas will probably impress the reader in two ways: First, the great number of North American seas, and, second, their rather free intercommunication. The multiplicity of seas, which in the main were of Paleozoic time, unmistakably indicates shallow bodies of water variously separated by more or less ineffective land bar- riers. A survey of the paleogeographic maps presented in this paper will make this fact abundantly evident, and it may be likewise observed that not only did the marine waters flow in on the land from the four sides of the North American continent, but that the seas were localized among lands that suggest an archipelago of large islands. Further study will show that the Paleozoic continental seas began in a small way, pulsated back and forth over the continent, and, if a few irregularities are disregarded, in- creased in area until they almost completely submerged North America in Middle Ordovicic time. This great inundation was dominated by the Pa- cific. The oscillatory nature of the seas continued, yet during the Siluric the Arctic waters were the dominating force. With each recurring climax of submergence, however, it is seen that the pulsations became smaller and smaller until the close of the Paleozoic, when North America was again as large as it had been at the beginning of this era. For a long period the entire continent then remained positive except along the border region of the Pacific, which ocean during the Triassic overlapped great areas and in the late Jurassic developed the Logan sea. During this period, however, contraction and subsidence of this immense ocean had gone on, and thrust- ing now took effect, giving birth to the Sierra Nevadas. About this time subsidence also took place over much of eastern Mexico, being probably caused by the thrusting of the Pacific ocean indicated in the appearance of the Sierra Nevadas. This thrusting was continued for a period equal in length to the Comanchic, and resulted in the greater extension of the Gulf of Mexico not only over the larger part of Mexico, but the syncline stretched into the United States as far north as Kansas. A marked but short withdrawal of this sea then took place, when the same syncline was further extended, giving rise to the Coloradoan sea connecting the Gulf of Mexico with the Arctic ocean. That this trough continued to subside is shown by the fact that in Montana it contains about 12,000 feet of marine deposits of Colorado and Montana age, and these series are said to be followed by a similar thickness of Laramie and Livingston beds. In the development of this trough must be assumed the gradual rise of the Rocky mountains in the West, a considerable portion of whose elevation has gone toward filling the syncline. Along the northern Atlantic thrusting culminated with the early Per- mic revolution, since which time this ocean has gradually eaten its way 450 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA westward, assisted by block faulting seaward either in late Jurassic or early Comanchic. This action continued until late in Cretacic times, when the ocean overlapped the continental shelf all along the coast from. New Jersey southward, thus connecting with the Gulf of Mexico overlap. The various seas are defined as follows, being arranged in alphabetical. order : Acadian trough.—See Saint Lawrence sea. Alaskan sea—The Paleozoic and Mesozoic seaways about Yukonia. Usually these waters were but the overlapping continental extensions of the Arctic and North Pacific oceans, but at times the individual parts. were united and then submerged most of Alaska. This sea was also at. times in connection with Mackenzie basin. Appalachian sea.—In one way or another this continental sea has been recorded in geological literature since the work of W. B. and H. D. Rogers in 1840. Williams*® appears to have been the first to give it the name “Appalachian basin,” while Walcott called it “Appalachian sea.”*t It comprises the Appalachian region of Dana‘? and his “eastern interior east of the Cincinnati uplift.”** Other names applied to the same sea are: “Appalachian gulf” or “strait,’** “Appalachian Valley trough” with ref- erence to the eastern part with Cambric-Ordovicic formations,** Cum- berland basin for the post-Ordovicic formations to the west of the “Appa-- lachian Valley fold or barrier,’’*® and “Cumberland channel,”’** which em- braces the southern area between the Cincinnati axis and Appalachia. Appalachian sea refers to the continuously subsiding, narrow, Paleozoic syncline, “or group of troughs,”*® to the west of Appalachia, extending from Alabama into eastern New York. In Pennsylvania this trough con- tains approximately 30,000 feet of deposits. The Appalachian sea was not distinctly separated from the Mississippian sea until the rise of the Cin- cinnati axis, previous to which time the dominating Pacific waters lapped Appalachia. Subsequently this sea received its faunas in the main from (1) the Mexico-Caribbean mediterranean, (2) the Atlantic or rather Pos- eidon ocean, and (3) the Mississippian sea. When these were from the first named source entrance was effected by way of the Mexico embayment. During the late Cambric and the Ordovicic Atlantic faunas migrated into: 40 Williams: Bull. Geological Society of America, vol. 1, 1890, p. 481. 41 Walcott: Proc. American Association for the Advancement of Science, vol. 42, 1894,. map and pp. 141-145. 42 Dana: Manual of Geology, 1874, p. 146. 438 Dana: Bull. Geological Society of America, vol. 1, 1890, p. 41. 44 Willis: Maryland Geological Survey, vol. 4, 1902, pp. 40, 52. 45 Ulrich and Schuchert: Rep. New York State Paleontologist, 1902, p. 638, and map.. 46 Tbidem, pp. 638, 647, 649. 47 Williams : American Journal of Science, vol. 3, 1897, p. 398. 48Dana: Bull. Geological Society of America, vol. 1, 1890, p. 42. NEGATIVE CONTINENTAL ELEMENTS ADT this sea from the Saint Lawrence sea by way of the Champlain trough,. and during the early Devonic through the Connecticut trough. During much of Paleozoic time, however, the faunas came directly from the Atlantic through New Jersey strait. This connection with the Missis-- sippian sea was either a wide one through the Ohio basin or was much restricted by the more or less neutral land Alleghania. In general, it may be said that the faunas of the Appalachian sea were in harmony with those of the Mississippian sea because of their open communication one: with another. At times, however, these seas were completely isolated, in which case the Appalachian sea, particularly its northern end, took on a’ decided Atlantic faunal aspect, and it should be stated that the Appa- Jachian sea always showed more of this character than did the Mississip- pian sea. During the late Cambric and the greater part of the first half of the Ordovicic the Appalachian sea deposits were in the main of a calcareous dolomitic nature; yet subsequently, when the trough was clearly defined,. its sediments were chiefly muds and sands. This was especially true of the: northern portion of the trough, and attained its climax in Devonic times, when 10,000 feet of Middle and Upper Devonic strata were laid down.*® The present writer believes that the major amount of this material came from Acadia, or more specifically from Taconia, and that the cause of this great thickness was the narrowness of the Appalachian trough, hemmed in on the west by Alleghania. The first restriction of this trough came with the Cincinnati uplift, which was due to the Taconic revolution that began in early Utica time and culminated with the Richmond. The rise of the more or less neutral land Alleghania was also contemporaneous with this uplift. Ulrich thinks that the first restriction appeared as early as the Lower Mohawkian. He states that these deposits nearly all over-. lapped to extinction on its flanks. The Appalachian sea was at times divided into two parts by a land area in southern Virginia, when either the northern or the southern portion, or both, may have been occupied by independent marine waters. To the northern Appalachian sea, extending from New York (west of Taconia) to Virginia (west of Appalachia), the name New York basin is here ap-- plied, as the history of this area is best known in the State of New York. The region about Albany, New York, has been called by Dana®°® the “Northeast bay.” The southern Appalachian sea may take the name Cumberland basin ; it extended nearly from Tennessee to Alabama, where 42 Willis: Bull. Geological Society of America, vol. 18, 1907, p. 399. °° Dana: Bull. Geological Society of America, vol. 1, 1890, pp. 42-43. 45? C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA it merged into the Mexico embayment. The Paleozoic deposits of this basin are not so thick as those of the northern area. In the Ordovicic the eastern part of the Cumberland basin was occupied by two distinct faunal elements, the western one of which contained the life of the Mississippian sea, while the other derived Atlantic (Poseidon) faunas through the Mexico embayment. The most easterly portion of the Cumberland basin area has been named Lenoir basin.*1 This basin was again medially divided by “several disconnected longitudinal folds high enough to affect the direction of currents, and consequently the character of the sediments, and in a smaller degree faunal distribution. In a gen- eral way the deposits may be divided into an eastern, Athens trough, and a western series, Knoxville trough” (Ulrich and Schuchert, 1902, page 644). Arctic ocean.—Of all the permanent basins this ocean has had the least effect, physically and faunally, on the North American continent. During the Siluric, however, its waters attained a broad entrance into the United States through the medial regions of the continent. In Middle and Upper Devonic times its inundations were considerable, though less than half those of the previous period, while in the Mississippic they were far less effective. But once, subsequently, during the Cretacic, did this ocean have free access to the continent through the Coloradoan sea. Arizona basin.—See Sonoran sea. Athens trough.—See Appalachian sea. Atlantic ocean.—Throughout the Paleozoic, and during most of the Mesozoic, there was no Atlantic ocean in the sense of today. During the vast time indicated above the North and South Atlantic were independent bodies of water separated by Gondwana, uniting Africa and South Amer- ica. For this reason it is not proper to speak of the Atlantic until after late Mesozoic time, when the southern Atlantic, or Nereus, and the north- ern Atlantic, or Poseidon, were more or less widely united. For further remarks, see Poseidon ocean. Baffin basin.—See Hudson sea. Californian sea.—A continental border sea of the Pacific across Cali- fornia during the Paleozoic and Mesozoic. In the Triassic this sea ex- tended to Nevada, Idaho, Oregon, and Washington. Like most continental border regions, the Californian sea was considerably affected by volcanic deposits. These are known in Devonic, Pennsylvanic, and early Mesozoic time. For the present this term has a very indefinite meaning. Walcott”? 51 Ulrich and Schuchert: Rep. New York State Paleontologist, 1902, pp. 634, 644, and map. , 52 Walcott: Proc. American Association for the Advancement of Science, vol. 42, 1894, pp. 129, 145, with map. NEGATIVE CONTINENTAL ELEMENTS Aye applied “Californian sea” to the area of Paleozoic deposits in California and “of western British Columbia.” In the present work the latter area is referred to the Vancouverian sea. Caribbean mediterranean.—See Mexico-Caribbean mediterranean. Champlain trough.—See Saint Lawrence sea. Chazy channel.—See Saint Lawrence sea. Coloradoan sea.—The western great inland continental sea of Cretacic time extending from the Gulf of Mexico to the Arctic ocean. Its individual parts were the Mackenzie and Rocky Mountain basins, defined under Cor- dilleran sea. The eastern Great Plains area, from Manitoba to Oklahoma, may be called the Great Plains basin. Connecticut trough.—See Saint Lawrence sea. Cordilleran sea.—This great Paleozoic continental sea of the Rocky Mountain region has been known a very long time. Its syncline was due to thrusting of the Pacific mass, and its faunas were usually dominated by those of this ocean. It probably came into existence long before the Cambric. Dana’* has called it the “Western Interior or that of the East- ern Rocky Mountain slope.” The name as used by the writer was given by Walecott.°+ Willis®® designates it the “Rocky Mountain trough,” and Wilhams’® has included the northern end of this sea in his “Dakota chan- nel,” a name that will be used in connection with the Cordilleran sea. During its time of maximum inundation the Cordilleran sea extended from the Arctic ocean to the east of Yukonia and Cascadia, and united with the Pacific ocean by way of the Great Basin and southern California. At times it was also connected southward with the Sonoran sea. Its faunas were derived chiefly from the Pacific and less persistently from the Arctic ocean, and these elements combined, or the former alone, may have spread during the earliest Paleozoic as far eastward as Appalachia and Taconia. After Siluric times the Cordilleran sea was never in wide open communication with the Mississippian sea, but these two great conti- nental basins had as a rule their own distinct faunas, derived either from the Pacific or the Atlantic (including the Gulf). The Cordilleran sea had several distinctive parts that must be named and defined for easy reference. The most persistent portion was the Great Basin area, well known since the work of King (1878. See also Dana, 1890, page 46), which embraced eastern Nevada, northwestern Utah, western Wyoming, southeastern Idaho, and the Inyo region of California. 53 Dana: Bull. Geological Society of America, vol. 1, 1890, p. 41. _ 54 Walcott: Proc. American Association for the Advancement of Science, vol. 42, 1894, pp. 143, 144, with map. *° Willis: Bull. Geological Society of America, vol. 18, 1907, p. 399. °6 Williams: American Journal of Science, vol. 3, 1897, p. 394. “> ADd4 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA According to King, there were 32,000 feet of Paleozoic sediments in this great syncline. As the faunas of this basin were decidedly Pacific in origin, it must have had free communication with the dominant ocean, seemingly through central California. Southward the Great Basin was often in connection with the Sonoran sea by way of the Arizona basin. To the north this area passed into the Rocky Mountain basin of Wyoming and Montana (Dana, 1890, page 46), and it frequently extended far into the north across Alberta, eastern British Columbia, and western Atha- basca (northern Rocky Mountain trough of Willis, 1907, page 399), then uniting with the Pacific ocean by way of the Mackenzie basin. The latter extended along the valley of the Mackenzie river between Yukonia and Mackenzia. In the region of the Rocky Mountain basin the Cordilleran sea often overlapped southeastward across the Dakota states, and connected with the Mississippian sea through the Iowa basin. This was the Dakota basin, first designated by Wilhams as the “Dakota channel” (1897, page 394). The original definition made this term applicable to Devonic waters hay- ing Pacific-Arctic assemblages of life and in restricted communication with the Mississippian sea. The name, however, is of more general appli- cation for Paleozoic seas repeatedly covering the same common area. Dur- ing Middle and late Ordovicic the Dakota basin was in wide open com- munication with the Mississippian sea, at which time there was a general commingling of northern Cordilleran and Hudson Sea faunas with those of the Mississippian. During the Siluric the Dakota basin connected for the last time with the Hudson sea north of the Dakota states, while in the Devonic it stretched far across these states; in the Mississippic and Penn- sylvanic appearing to be less wide and extending farther south across South Dakota and northern Nebraska. Dakota basin.—See Cordilleran sea. Exploits channel or trough.—See Saint Lawrence sea. Fundy basin.—See Saint Lawrence sea. Gaspé-Worcester trough of Dana®* had no individual development as a seaway, as far as the writer can learn. Its northern end was a part of the Saint Lawrence trough, while the southern portion represented an indefi- nite depression more apparent in the present structure than in the Paleo- zoic seas. It is defined as follows: The trough was situated between the New Hampshire range and the Mount Desert range. It extended “from Gaspé, on the bay of Saint Lawrence, over much of northern New Bruns- wick and central Maine, and continued to Worcester, Massachusetts.” Great Basin.—See Cordilleran sea. s™ Dana: American Journal of Science, vol. 39, 1890, p. 380. NEGATIVE CONTINENTAL ELEMENTS A55 Great Plains basin.—See Coloradoan sea. Hudson sea——A very shallow continental V-shaped sea of enormous extent during Ordovicic and Siluric times, having wide open connection with the Arctic ocean across Franklin archipelago, and by way of the Dakota basin through the Cordilleran sea. During the Ordovicic there ‘was also free communication with the Atlantic by way of Baffin basin. In southern Baffin Land are Middle Ordovicic faunas of the same aspect as those of Akpatok island, in Ungava bay. Because these localities are so near the present deep seaways of Hudson strait and Davis strait, it ‘seems reasonable to assume this Atlantic (Poseidon) communication. To | the south this wide sea narrowed between Ungava and Keewatinia; the northern portion of this area may be known as James basin and the south- ern part as Ontario basin. During the Middle and Upper Ordovicic these basins communicated uninterruptedly with the Mississippian sea, but far less openly with the Saint Lawrence sea. In the Siluric the southern - communications were continued, but the eastern opening was of short duration. In the Middle Devonic the Mississippian sea occupied the ‘Ontario and James basins for the last time. Indiana basin.—See Mississippian sea. Iowa basin.—See Mississippian sea; also Cordilleran sea. James basin.—See Hudson sea. Kansas strait—See Mississippian sea. Kentucky strait.—See Mississippian sea. Knoxville trough.—See Appalachian sea. Lenow basin.—See Appalachian sea. Levis channel.—See Saint Lawrence sea. Logan sea.—An extensive, late Jurassic, western continental sea of very short duration, with northern Pacific connections. It extended from northern British Columbia across northern Cascadia, thence southward throughout the Rocky Mountain area into northern Arizona, and east- ward into western South Dakota. This sea was correctly mapped by W. N. Logan,*® for whom it is named. Mackenze basin.—See Cordilleran sea. Mediterranean refers to those deep extensive bodies of marine waters situated between continents, with usually but one opening into an ocean. ‘These were also permanent seas, true negative elements, whose boundaries, however, are changing more constantly than those of the oceans. The Gulf of Mexico-Caribbean sea has been named by Kriimmel “the Ameri- can mediterranean.” See Poseidon ocean. 8 Logan: Journal of Geology, Chicago, vol. 8, 1900, p. 245. 456 C. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA Mezxico-Caribbean mediterraneans.—These mediterraneans appear to be of very ancient origin; the former certainly existed previous to the Cam- bric. There is today free communication between them by way of the Yucatan channel, which may not have been the case throughout the Paleo- zoic. ‘The Caribbean may have occurred as a deep-sea extension of the Pacific, land locked in the east, and stretching across Costa Rica and Pan- ama during the Paleozoic and Mesozoic, with overlaps across northern Archiguiana. Its Atlantic, or Poseidon, connections across Antilha (lesser Antilles) were established either late in Mesozoic or early in Cen- ozoic times. Throughout most of the Paleozoic the Mexico mediterranean was in open communication with the Mississippian sea by way of the Mezico embayment. The Mexican gulf “once stretched to the Arctic sea,” and was “in early time but the deeper part of the continental ocean” (Dana, 1856, 345). It connected with the Pacific by way of the Sea of Tehuan- tepec certainly in the Siluric and Pennsylvanic, and probably also in the Devonic. During Mesozoic times Mexico and the Gulf states were widely inundated by the gulf, although this submergence was less in the Tertiary. The Paleozoic faunas of the Gulf of Mexico greatly affected the life of the Mississippian sea, with its decided South American connections which spread north along the western side of Archiguiana. The faunas in the Mesozoic, however, were Atlantic and agree best with those of southern Europe, though additions at times appear from western South America. Antillia seems to have been submerged for the first time by the Mexico- Caribbean mediterranean late in the Mesozoic, and thus remained during the Eocene and Oligocene, when this region is represented by one vast ocean with a few small islands. Mexico embayment.—See Mississippian sea. Mississippian sea.—This vast Paleozoic continental sea was first defined’ by Dana®® as “the Central interior or Mississippi basin,” but later was. changed by Walcott® to “Mississippian sea.” This shallow Paleozoic sea variously occupied more or less of the Missis-- sippi and Ohio drainage areas, and was usually in free communication with the Appalachian sea. During Ordovicic and Siluric times it was also. in open connection with the Hudson and Cordilleran seas, but after the Siluric only occasionally with the latter area. The chief and most per-- sistent source of its waters and faunas was the Mexico mediterranean, and secondarily the Atlantic (= Poseidon) by way of the Appalachian sea. 52 Dana: Bull. Geological Society of America, vol. 1, 1890, p. 41. 6 Walcott: Proc. American Association for the Advancement of Science, 1894, p. 144, with map. Also see Ulrich and Schuchert, Rep. New York State Paleontologist, 1902, pp. 636, 660. NEGATIVE CONTINENTAL ELEMENTS Ai Only during Middle and Upper Ordovicic times was there connection with the Saint Lawrence sea north of Adirondackia. Subsequent to the Ordo- vicie the main topographic features of the Mississippian sea were the islands of the Cincinnati uplift and the other islands or peninsulas Mis- souria, Wisconsia, Kankakeia, and Alleghania. ‘These were low lands more or less subjected to marine inundations. Cincinnatia, Missouria, and Wisconsia were the most persistent, and all of these lands had their origin in movements previous to the Middle Mohawkian of the Ordovicie. Outside of the Oklahoma basin the deposits of the Mississippian sea are far less in thickness than those of the northern Appalachian trough or the Great Basin of the Cordilleran sea. In the main they consist of cal- eareous shales and limestone often inclosing a profusion of fossils. The strata are often warped and rarely folded (exception, the Wabash axis), but in places there is considerable faulting. The constantly changing topographic features of the Mississippian sea cause its deposits and faunas to be much localized and variable. These conditions make the work of the biologist all the more interesting, because difficult.*t To facilitate the description of these localized sedi- ments and faunas it is necessary to name the various basins bounded by the featureless lands. The Mexico mediterranean effected a wide entrance through the Mexico embayment between Llano and Appalachia, an area now deeply buried beneath post-Paleozoic deposits. Northeasterly this embayment may have continued into the Jndiana basin® to the west of the Cincinnati uplift and east of Missouria and Kankakeia, or into the Appa- lachian sea by way of the Cumberland basin. The latter may also have extended into the Ohio basin of Ohio and western New York on the east- ern side of the Cincinnati uplift and west of Alleghania (a restricted usage of Ohioan province**), or the Ohio basin may have been in com- munication with the Indiana basin around the north end of Cincinnatia. During the Ordovicic and Siluric the Ohio and Indiana basins again may have had open communication with the Ontario and James basins and the Hudson sea. In Devonic times this northern extension did not pass beyond the James basin, and in late Devonic the northern boundary of the Mississippian sea was restricted to the Ohio and Indiana basins. At dif- ferent times the latter basins were connected by Kentucky strait, which passed across the Cincinnati uplift in Kentucky. During the Devonic Traverse basin (Schuchert, 1903, 150) became the thoroughfare for the passage of the Cordilleran faunas of the Jowa 61 Also see Dana regarding this. Bull. Geological Society of America, vol. 1, 1890, pp. 438, 44. 62 Schuchert : American Geologist, 1903, p. 148. 63 Ulrich : Professional Paper, no. 24, of the U. S. Geological Survey, 1904, p. 91. XLII—BuuLu. Grou. Sec. AM., Vou. 20, 1908 458 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA basin into the Mississippian sea. This basin was situated between Kanka- keia and Wisconsia, and the waters passed around the northern end of the former land or across it. At other times Traverse basin was part of the Mississippian sea. In the Devonic and early Mississippic, Iowa basin was part of the Cor- dilleran sea, but during the Cambric and Ordovicic it comprised the north- western waters of the Mississippian sea in the states of Iowa, Minnesota, and Wisconsin. In the Siluric it embraced Iowa, Illinois, and Wisconsin, while during Pennsylvanic time it included the region immediately about Towa. Returning to the Mexico embayment, it is seen that its waters may have extended in a westerly direction around Llano into the Oklahoma basin to the south and southwest of Missouria and east of Siouxia. This syncline was a very persistent one, and according to Taff has a mass of Paleozoic. sediments varying in thickness from 18,000 to 23,000 feet. During the Ordovicic this basin was in open communication with the Sonoran sea, but later was restricted to Mississippian waters and faunas. In Mississippic and Pennsylvanic times the Oklahoma basin passed north across western Missouria into the Iowa basin; this passage may be known as Kansas strat. New Jersey strait—See Appalachian sea. New York basin.—See Appalachian sea. Ocean, according to the Century Dictionary, applies to the great out- ward sea, the Atlantic, as distinguished from the inward sea, the Medi- terranean. The word refers to the independent, vast, and permanent deep seas as the North Atlantic and Pacific negative elements. Ohio basin.—See Mississippian sea. Oklahoma basin.—See Mississippian sea. Ontario basin.—See Hudson sea. Ottawa bay.—See Saint Lawrence sea. Ouray basin.—See Sonoran sea. Pacific ocean.—During the Cambric and Ordovicic this vast. and most ancient body of marine water mightily affected the North American conti- nent, and spread its faunas not only along the shores of Appalachia, but in the early Ordovicic extended them into the Saint Lawrence sea as far as northwestern Newfoundland. Beginning with the Cambric, it connected with the Arctic sea to the east of Cascadia, but this union was in general not that of a wide sea. In Middle, and again in late Upper, Ordovicic time, however, there was a widespread inundation of the continent. At these times the faunas appear to have been dominated by that of the Pa- cific ocean. Later the life of the continental seas was not decidedly NEGATIVE CONTINENTAL ELEMENTS 459 affected by the northern part of this ocean until the late Devonic and early Mississippic, while during the late Pennsylvanic its faunas did not extend beyond Colorado and New Mexico. Barring the invasion of the Logan sea, it was ever afterward restricted more and more to the edge of the North American continent. In other words, the western side of the entire continent was progressively enlarged and pushed up higher and higher, thus restricting this ocean to its ever deepening basin. Poseidon ocean.—Throughout the Paleozoic the northern Atlantic waters were separated from the southern Atlantic by the great continent Gondwana, uniting Africa and South America across the medial region of | the present Atlantic. It is, therefore, not correct to speak of the northern Atlantic until the present form of this ocean has been attained, which seemingly had its inception late in the Mesozoic. Von Ihering** has named the southern Atlantic waters south of Gondwana Nereus (he writes it Nereis), evidently after the father of the 50 Nereids. The northern Atlantic he regards as a part of Suess’ Tethys (he writes it Thetis, one of the daughters of Nereus. but Suess distinctly refers to the consort of Oceanus, Tethys), the ancient Mediterranean that extended from the Atlantic to the Pacific and of which the present Mediterranean is the re- mainder. Since Tethys has its own and very distinct geologic history, and seemingly always had restricted communication with the northern Atlan- tic, it will be best to use this term in the sense given it by Suess. As the northern Atlantic has an independent evolution from the southern Atlantic, it is here proposed to call the former the Poseidon ocean, after “the lord of the sea,’ known to the Romans as Neptune. “His home is a cavern in the depths of the sea, and not only does he know all the secrets of his element, but, like the sea-gods of the Babylonians and Germans, he possesses in general immeasurable wisdom. But he who would question him must first overpower him in a wrestle, and force him, despite his power of assuming like water itself a variety of shapes, to communicate to him his knowledge” (Steuding). Repeatedly during the Paleozoic the waters of the Poseidon ocean en- tered the continental seas and there dispersed their faunas. At no time, however, did this life dominate these seas as did that derived from the Pacific realm during the early Paleozoic, and later that of the Mexico mediterranean. Subsequent to the earliest Mississippic the North Atlan- tic was excluded by land barriers, and in the Saint Lawrence sea after late Pennsylvanic time it did not again leave a record of its life. Near the 64'Von Ihering: Archhelenis und Archinotis, 1907, p. 310, and map. * Suess: Antlitz der Erde, III, pt. 1, 1901, p. 25. Natural Science, vol. 2, 1893, p. 188. ee Ae area i 460 C. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA close of the Mesozoic, and subsequently, it was an overlapping marginal sea. Potomac embayment.—An embayment of the Atlantic ocean across the’ Piedmont plateau, the “roofing slate area” of Virginia and Maryland. There is no evidence that this bay spread south of Buckingham county, Virginia, but it probably extended northeast across Delaware and New Jersey, uniting with New Jersey strait. Relict seas——These are brackish and finally fresh-water lakes, often of very large size, which have been connected with the ocean, but are now completely encircled by land. Examples are Caspian, Baikal, Tanganyika, etcetera, lakes, which still contain modified relicts of a former ocean. In America there is as yet no evidence of fossil relict seas, for all the pre- vious continental seas appear to have been too shallow to permit of their origin during periods of continental emergence (see Walther: Einleitung in die Geologie, 1893, 130-134). Rocky Mountain basin.—See Cordilleran sea. Saint Lawrence sea——The work of the Canadians made this sea known to American geologists years ago, but Dana®® appears to have been the first to define its limits. It is his “Eastern Border basin or region,” east and northeast of the Green Mountain range, and including New England, eastern Canada, New Brunswick, western Nova Scotia, the Gulf of Saint Lawrence, and Newfoundland. This sea, trending northeasterly, was distinctly an interior sea, and owed its origin and position to the thrusting of the North Atlantic mass against the Laurentian shield. Dana*’ writes: “Even the far east Paleo- zoic area, including much of Nova Scotia and eastern New Brunswick, had its outside Archean boundary, and was a trough of Archean confines, not the margin of the open sea.” The portion of this sea best known is the area of the Saint Lawrence river and gulf to which has been applied the name Saint Lawrence trough®* (see also Gaspé-Worcester trough). This trough, which was gen- erally narrow, was in open communication with the northern Poseidon ocean and often transmitted its faunas freely to the Appalachian sea. As a tule, its life was that of the North Atlantic, being in harmony with the biotas of northern Europe. During the Ordovicic, however, there was a complexity of elements that are clearly of two widely different origins. Along the northern side of the embayment are found faunas that are posi- tively of Mississippian derivation and that now occur scattered all the 6 Dana: Manual of Geology, 1874, p. 146. § Dana: Bull. Geological Society of America, vol. 1, 1890, p. 48. 6 Dana: Ibidem, 1890, pp. 38, 379. Manual of Geology, 1895, p. 536. NEGATIVE CONTINENTAL ELEMENTS | A61 way from Adirondackia to Newfoundland. Closely adjacent to, or even thrust over on, these faunas are found others, usually graptolites, that are manifestly of the same province as those of northern Europe. These faunas are strikingly different, and as the entire Acadian region is one of extreme crushing and overthrusting, Ulrich and Schuchert®® have assumed the existence of a land barrier to keep these two faunal provinces distinct. This fold or land barrier between the two seaways came into being at the close of the Cambric, and has been called the “‘Quebec bar- rier.” To the northwest of this barrier was their Chazy channel, while on the opposite side of the same fold was their Levis channel. The definite Atlantic faunas of the latter may be traced southwesterly as far as New Jersey. These two troughs appear to have remained distinct until about Utica (?) time, when the Chazy basin ceased, owing to the folding and elevation in force during the Taconic revolution. In late Chazy time the Saint Lawrence sea had a distinct bay-like pro- longation extending along the Ottawa valley north of Adirondackia; this has been named “Ottawa bay” (Ulrich and Schuchert, 1902, 639). Dur- ing the later Ordovicic this depression was invaded either by the Missis- sippian or the Saint Lawrence sea; subsequently it appears to have been land, yet may again have been beneath the sea in Siluric time. The connection of the Saint Lawrence sea with the Mississippian sea was of very short duration, and occurred north of Adirondackia during the Middle and Upper Ordovicic. During the late Cambric and much of the Ordovicic, however, there was much communication with the Appa- lachian sea through the Champlain trough (Dana, 1896, 461), but this passage was closed by the Taconic revolution of late Ordovicic time (see Dana, 1890, 43). In the early Ordovicic this channel was narrow and directly continuous with the Chazy channel, but subsequently it appears to have been considerably wider, embracing the Levis channel, its deposits occurring east as far as lake Memphremagog. During the Siluric there was no direct communication between the two seas, but beginning with the New Scotland interchange of faunas was again resumed, but now by way of the Connecticut trough,”° which extended across the Taconic moun- tains into the New York basin of the Appalachian sea. The interchange of faunas was then continued well into the Onondaga, after which time Acadia was repeatedly compressed and elevated, thus forcing these two seas ever farther apart. The Connecticut trough was bounded on the west 6 Ulrich and Schuchert: Rep. New York State Paleontologist, 1902, pp. 630-639. 7 Dana: Bull. Geological Society of America, vol. 1, 1890, p. 38: American Journal of Science, vol. 39, 1890, p. 380. Manual of Geology, 1895, p. 461. Schuchert: American Geologist, 1908, p. 151. Clarke: Memoir no. 9, New York State Museum, pt. 1, 1908; pt. 2, 1909. 462 C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA by the Green Mountain axis and on the east by the New Hampshire range. It contains, according to Dana, “Lower Silurian, Upper Silurian, and Devonian beds in the state of metamorphic schists . . . and crys- talline limestones, but nevertheless affording fossils of each of the eras for their identification; and containing also the Connecticut Valley sand- stone.” The “Acadian trough” of Dana‘ begins “in northern Newfoundland west of the northern part of Long range, and ex- tending to St. George bay and Cape Ray, in southwestern [Newfoundland] ; passing thence over the region of the Magdalen Islands, in the bay of St. Law- rence to Nova Scotia and New Brunswick on either side of the bay of Fundy; and thence to the region of Boston and Massachusetts Bay, and to that of Narragansett Bay in Rhode Island; and including rocks from the Cambrian to the Jura-Trias as identified by fossils.” The northern end of this trough to the Bay of Fundy region is well established, but the southwestern portion in Massachusetts and Rhode Island is based on Cambric and Pennsylvanic deposits. ‘The former may be correctly placed in this depression, but the latter are fresh-water de- posits that have the strike of the New Hampshire range. To the writer, therefore, they appear to form a local structural basin having no relations with the Acadian trough. The latter also includes the “Fundy basin” of Dana (1890, 37), an area which was receiving marine deposits as late as the Oriskanian. The Saint Lawrence sea continued across northern and medial New- foundland, along the basin of Exploits river, and thus was in direct connec- tion with the North Atlantic. This is the “Hzploits trough” of Dana.” This trough extended “along Exploits river across Newfoundland, south- westward, to La Poile bay and White Bear river, the length 200 miles.” The main or southern mass of Newfoundland appears to have been land since Proterozoic times, and was smallest during the Lower Cambric, when it was overlapped not only in the north, but also in the south. Sub- sequent to the Cambric the southern portion of Newfoundland has been land continuously, while most of the northern or peninsular region was attached to Ungava after Ordovicic time. Exploits channel continued at intervals beneath the sea until about the middle of the Mississippic, when it was added permanently to the land. Sonoran sea.—This was a fairly persistent Paleozoic continental sea ex- tending across northern Sonora, southern Arizona and New Mexico, and 71 Dana: American Journal of Science, vol. 39, 1890, p. 380. ™ Dana: American Journal of Science, vol. 39, 1890, p. 381. Manual of Geology, 1895, p. 461. NEGATIVE CONTINENTAL ELEMENTS 463 medial Texas. As its faunas were those of the Pacific realm, it must have had connection with that ocean across Baja California. ‘The Sonoran sea was often in communication with the Cordilleran sea by way of the Ari- zona basin, situated between the lands Ensenada and Utah. In the Upper Devonic especially, but also in the Mississippic and Pennsylvanic, this sea had a northern extension across western New Mexico and eastern Arizona and reaching into western Colorado; this may be known as the Ouray basin. The Devonic faunas of this basin were different from those of the Cordilleran sea. At certain times during the Cambrie and the Ordovicic, the times of wide Pacific inundation, the Sonoran sea was in open communication with the Mississippian sea. Subsequently, however, these two seas were sepa- rated by a greatly lengthened expanse of land. Suwanee strait—During the Eocene, Oligocene, and Lower Miocene central and southern Florida appeared as an island. The waterway be- tween insular Florida and Appalachia, connecting the Atlantic and the Gulf of Mexico, Dall and Harris have named “Suwanee strait.” The same opening undoubtedly existed during the Cretacic, but there is no evidence of it across Antillia-Appalachia until the time of the Lower Devonic. From thence into the Cambric the southern Mississippian sea again and again had faunas that are Atlantic or Poseidon in their origin. On this evidence rests the separation of Appalachia from Antillia in order to per- mit the Poseidon faunas passage across Florida into the Mississippian sea. Sea of Tehuantepec.—At present North America and Central America are bound together by a narrow strip of land, the passes of which are not high above the sea. The geology of this region is known only along gen- eral lines. Honduras appears as an ancient land nucleus, to the north of which, in Guatemala and Chiapas, occur Pennsylvanic and Meso- zoic deposits. As most of Mexico north of southern Oaxaca seems to have been land during the Paleozoic, and as certain of the faunas of the Missis- sippian sea must have entered the Mexico mediterranean across the syn- cline of Guatemala, this marine thoroughfare may be named the Sea of Tehuantepec. Traverse basin.—See Mississippian sea. Vancouverian sea.—This comprises the Pacific extensions across British Columbia, the character of which is that of an interior continental sea. The eastern edge of the land bounding it on the west seems to be repre- sented by Queen Charlotte islands. Dawson‘ regards the area of this sea as a syncline ; therefore there should be a land to the west parallel to Cas- cadia. For the present the definition of this bordering continental sea is 3G. M. Dawson: Bull. Geological Society of America, vol. 12, 1901, p. 73. | 464 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA obscure, but during the late Paleozoic, early Mesozoic, and the Tertiary it was subject to much volcanic activity. The Nicola formation of Trias- sic time alone has a thickness of 13,590 feet, nine-tenths of which are of volcanic origin. PALEOzoIc LANDS, OR POSITIVE ELEMENTS (See map, plate 49) James D. Dana was apparently the first to point out the permanency of oceanic and continental areas. From the standpoint of a Laplacian‘* he stated the following in his paper “On the volcanoes of the moon,” which appeared in 1846:" “On our globe the continents have to a very great extent been long free from voleanie action. A glance at a map of Asia and America will make this ap- parent. It is usual to attribute this almost total absence of volcanoes from the interior of the continents to the absence of the sea; but it is fatal to this popu- lar hypothesis, that the same freedom from volcanoes existed in the Silurian period, when these very continents were mostly under salt water, a fact to which the widespread Silurian rocks of America and Russia testify. Over the oceans, on the contrary, all the islands excepting the coral, are igneous—and the coral may rest as we have reason to believe on an igneous base. “Tt is therefore a just conclusion that the areas of the surface constituting the continents were first free from eruptive fires. These portions cooled first, ‘and consequently the contraction in progress affected most the other parts. The great depressions occupied by the oceans thus began; and for a long period afterward, continued deepening by slow, though it may have been unequal, progress. This may be deemed a mere hypothesis; if so, it is not aS groundless as the common assumption that the oceans may have once been dry land, a view often the basis of geological reasoning. “Before the depression of the oceanic part of our globe had made much progress, the depth would be too shallow to contain the seas, and consequently the whole land would be under water. Is it not a fact that in the early Silu- rian epoch nearly every part of the globe was beneath the ocean? [What he has observed here is the Trenton inundation; it is the largest to which North America has been subjected.] . . . The depth of water over the continental portions would be very various; but those parts which now abound in the relics of marine life, were probably comparatively shallow, as amount of press- ure, light, and dissolved air, are the principal circumstances influencing the distribution of animals in depth. . . . Here then we see reason for what has been considered a most improbable supposition, the existence of an im- mense area covered in most parts by shallow seas and so fitted for marine life. a 7™4 According to the planetesimal hypothesis of Chamberlin and Salisbury, the perma- nency of oceanic and continental areas.is also held, but the method leading to the origin of the oceans is different from those described by Dana. (See their Geology. vol. II, 1906, pp. 84-88, 106-111.) 73 Dana: American Journal of Science, vol. 2, 1846, pp. 353-355. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 49 4 SJ ef ae Bs LEI LET (EIS “y a EEE. EY LIT 7 TEED (I LENS CE LoD LEEDS [LY 9 REF, [3a LEIA EN, OP LEE LL Es ~ 7 pS Se 2 = ey eS Se SS Hii —S Sas a es 5 me 0 A Br SD EY 2 OTs a DS a Sees Cn — oe a eee fC} — SS ees eee = ————y 2 —t = p ——— ¥ SH ey — fe NORTH AMERICAN PALEOGEOGRAPHY By CHARLES SCHUCHERT, 1909 SCALE (0050 © 100-200 «300400 500 _ 600 STATUTEMILES a >——————————————— PALEOZOIC POSITIVE ELEMENTS POSITIVE ELEMENTS 465 “If we follow the progress of the land, we find that with each great epoch there has been a retiring of the sea. . . . Subsequently, the progress on the whole was giving increased extent and height to the land and diminishing the area of the waters. Instead therefore of a bodily lifting of the continents to produce the apparent elevation, it may actually have been a retreating of the waters through the sinking of the ocean’s bottom. The process however has not been a continuous one: for during each epoch . . . there have been subsidences as well as seeming and actual elevations, and various oscillations of the continental surface, from subaérial to submarine and the reverse. ““And why should not the ocean’s bottom subside, as well as the land? [He states that there are 200 subsiding islands in the present Pacific (Dana, 1847: 94.)] What has given the continental portions of our globe their elevation, as compared with other parts, if not the unequal contraction of the whole?” “Ruptures, elevations, foldings and contortions of strata have been produced in the course of contraction. The greater subsidence of the oceanic parts would necessarily occasion that lateral pressure required for the rise and various foldings of the Alleghanies and like regions” (1846: 352-355). “Tf then, the typical form of a continent is a trough or basin, the oceanic border being raised into mountains; if these borders are so turned as to face the widest range of ocean; if the height of these border mountains and the ex- tent of the igneous action along them is directly proportioned to the size of the oceans,—the Pacific, accordingly, being girt with great volcanoes and lofty mountains, while the narrower Atlantic is bounded by smaller heights and but few volcanoes; if, moreover, volcanoes characterize the islands of mid-ocean and not the interior of the continents: what is the legitimate inference? “Most plainly, that the extent and positions of the oceanic depressions have some way determined, in a great degree, the features of the land; that the same cause which originated the one, impressed peculiarities on the other; that the two had a parallel history through past time—the oceanic depressions tending downward, the continents upward; in other words, that they have both been in progress with mutual reaction from the beginning of the earth’s refrigera- tion. The continents have always been the more elevated land of the crust, and the oceanic basins always basins, or the more depressed land.’ We have seen how the lands or positive elements originated, and in the language of Willis”? these are characterized as follows: “The geologic characteristics of a positive element are deep denudation, an absence of sediments of critical periods, and the corresponding prolonged dura- tion of the sum of unconformities. . . . They may have been depressed relatively to adjacent areas to some extent, but the algebraic sum of vertical movements has been upward, and has been positive as compared with other parts of the continent and the neighboring ocean bottoms. Whether they be regarded as horsts or protrusions resulting from radial elongation, their move- © ment is positive, and they may fitly be called positive elements.” Late in Proterozoic time, or just previous to the introduction of the 76 Dana: American Journal of Science, vol. 22, 1856, pp. 338-339. ™ Willis: Bull. Geological Society of America, vol. 18, 1907, p. 393. {|| Hi Ab66 -C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA Paleozoic continental seas, North America was certainly outlined, and was then even larger than it is at present. This fact is also noted by Walcott,*® who states: “The continent was larger at the beginning of the Cambrian period than during any epoch of Paleozoic time. . . . The continent was not then new. . . . It was approaching the baselevel of erosion over large portions of its surface. . . . I strongly suspect . . . that ridges and barriers of the Algonkian continent rose above the sea . . . that are now buried be- neath the waters of the Atlantic.” A survey of the Paleozoic paleogeography here submitted shows that the seas are of a continental character, for the marine waters of the four quarters of the northern hemisphere flow in on the depressed inland basins of the North American continent; further, that this vast land- mass has in the main always been bordered by high lands. The sediments of these seas are derived from the elevated areas of the continental mass and there was no “contribution of rock material from outside or aid from the ocean’s waves or currents, either those of the Atlantic or Pacific. For the most part, therefore, the growth of the continent . . . may be said to have been endogenous. It began to be exogenous on the Atlantic side in the Cretaceous era” (Dana). These facts and others stated on later pages prove that the North Amer- ican continent in its entirety has always been essentially positive, and was a greater land-mass just previous to the introduction of the Cambric and the Siluric seas than it is now. Moreover, during the Paleozoic its sur- face was variously buckled and elevated, but never very highly, owing to the inwardly moving Atlantic, Gulf, and Pacific margins, thus giving rise to shallow or continental island studded seas. During the early Mesozoic the North American continent was again larger than it is at present, but in late Mesozoic time, long after the Sierra Nevada deformation, another great syncline was developed giving rise to a continental sea that did vast endogenous work along the entire eastern side of the Rocky mountains extending from the Gulf to the Arctic ocean. Finally, since the disap- pearance of this, the Coloradoan sea, the North American continent has had throughout almost its present size and the work of its marine waters has been exogenous, due to overlaps of the oceans. As the North American continent now combines many positive ele- ments that are particularly noticeable as separate elements during Paleo- zoic times, when the mainland appears rather as a series of varying large and small islands, it is thought advisable to give each component part a 78 Walcott: Twelfth Ann. Rep. U. S. Geological Survey, 1891, p. 562. POSITIVE ELEMENTS A67 distinctive geographic name. These are here described in alphabetical order. Acadia.—An extensive marginal positive element with much volcanic activity, embracing the New England states, the maritime provinces of Canada, and Newfoundland. Its fundamental character was impressed upon it previous to Cambric times. During the Paleozoic it was variously dismembered by marine waterways, and was subjected to much elevation and erosion, apparently far more than Appalachia. The greater and more essential portion of this land was first described by Dana‘? as the “Acadian range.” He defined it as “commencing in the western part of northern Newfoundland, east of White bay, and extending thence to Saint George bay and cape Ray in southwestern, and beyond over eastern Nova Scotia.” According to the maps of the present writer, three lands are here involved, which are named in this memoir Newfoundlandia, Novascotia, and Bretonia. The term could, of course, be used for these lands when united, as is often the case in the Paleozoic, but the writer prefers to make use of Acadia in the widest sense, as defined above. Acadia also includes Dana’s ““Mount Desert range,” elsewhere described. Acadia was composed of a number of subelements, which may be defined as follows: Taconia®® embraced more or less of New England and is the largest of the subelements of Acadia. Apparently the greater part of it had been land since the Ordovicic. It included the New Hampshire range and the southern portion of Dana’s Mount Desert range. Newfouwnd- landia may be applied to the larger southern and most positive portion of the island, the northern peninsular region being more often a part of Ungava. Dana*' determined this land as the “Central-Newfoundland range,” and described it as “extending over a broad region east of the Exploits River valley, to the east side of Exploits bay.” Novascotia may be used for the province by this name, the northwestern portion of which was variously overlapped by the Acadian trough. Dana included this land in his Acadian range, and it is his “Nova Scotia protaxis.”*? Newbruns- wickia represents a small subelement at the northeast of the province of New Brunswick. Dana regarded this land as part of his Mount Desert range. Bretonia stands for the smallest subelement of Acadia, compris- ing the counties of Inverness and Victoria, Cape Breton island. It is also included in Dana’s Acadian range mentioned above. Acadian range.—See Acadia. , * Dana: American Journal of Science, vol. 39, 1890, p. 379. Bull. Geological Society of America, vol. 1, 1890, p. 37. Manual of Geology, 1895, p. 444. 8 Grabau: Journal of Geology, Chicago, vol. 17, 1909, p. 221. “Dana: American Journal of Science, vol. 39, 1890, p. 380. Dana: Bull. Geological Society of America, vol. 1, 1890, p. 37. A468 C. SCHUCHERT——_PALEOGEOGRAPHY OF NORTH AMERICA Adirondackia.—See Laurentia. Alleghania.—A narrow, slightly positive element extending from south- ern Kentucky into New York, having the strike of the Appalachian folds. It represents the western part of the Alleghany plateau of physiographers (Lippincott’s Gazetteer, 1906: 44). During times of general inundation it is probable that this area was a submerged bank, rather than a land. It was the western edge of the subsiding Appalachian synchnorium, and probably had its origin at the time of the Cincinnati uplift. Antillia.—This element embraced the Greater and Lesser Antilles and the Bahama islands. If there is any Paleozoic sedimentary history of this region it is unknown, but all writers treating of this subject agree in assuming that during the Paleozoic this region was land. Willis®** regards it as the southern extension of Appalachia, the view also of Frech,** who calls it “Paleoappalachia.” At different times, however, Antillia appears to have been separated from Appalachia by Suwanee strait, as indicated by the distinct Atlantic faunas that enter the Mexico embayment during this time. This fact furnishes the necessity for the term Antillia. Appalachia.—This name has long stood for a marginal positive ele- ment of very ancient origin, comprising most of the Atlantic states from southern New Jersey to eastern Alabama. While land had existed in this area continuously since the Cambric, there is no evidence that Appalachia was subjected to the same amount of elevation as Acadia. However, the middle and southern portions apparently extended far into the Atlantic during the Paleozoic—a condition maintained during the greater part of Mesozoic time by the decided rejuvenation of Appalachia during the Appalachian revolution. In the north the Atlantic repeatedly crossed Appalachia, and in the Ordovicic had a short embayment down what is now the Piedmont plateau to southern Virginia. Appalachia, being a bordering positive element, was nevertheless devoid of voleanic activity during the Paleozoic, as far as its present area is concerned. While this fact is in harmony with what is known regarding most of the lands con- tiguous to the Atlantic ocean, yet as Appalachia was subjected to much lateral pressure during the late Paleozoic it seems as though some volcanic action must have then existed. Does this condition signify that Appa- lachia extended farther into the Atlantic than is generally supposed? Appalachia was first defined by Dana in 1856.8 He states: 83 Willis: Bull. Geological Society of America, vol. 18, 1907, p. 394. Journal of Geol- ogy, Chicago, vol. 17, 1909, p. 206. 84 Wrech: Lethzea geognostica, 1901. % Dana: American Journal of Science, vol. 22, 1856, pp. 319, 344. See also Manual of Geology, 1874, p. 150. Bull. Geological Society of America, vol. 1, 1890, p. 36. Manual of Geology, 1895, p. 448. POSITIVE ELEMENTS A69 “The region toward the Atlantic border, afterward raised into the Appa- lachians, was already then, even before the Lower Silurian era closed, the higher part of the land” (319). ‘‘We hence learn that in the evolution of the continental germ, after the appearance of the Azoic nucleus, there were two prominent lines of development, one along the Appalachian region, the other along the Rocky Mountain region—one, therefore, parallel with either ocean. Landward, beyond each of these developing areas, there was a great trough or channel of deeper ocean waters, separating either from the Azoic area” (344). The name Appalachia was given by Williams.*® The term Appa- lachians was applied to these mountains by the Spaniards under De Soto, the word being derived from the neighboring Indians. Archiguiana.®*—This element comprises Venezuela and Guiana, and at times, according to Von Ihering, the Antilles also. Suess has lkewise defined this very ancient shield. In its history it is comparable to Lau- rentia, since through the action of the Pacific ocean the accretions of Paleozoic South America formed around its southern and western sides, while the effects of the Caribbean were slight, having practically the same value as those of the Arctic ocean on Laurentia. Bretonia—See Acadia. Cascadia.—Dana® thought that there might be an ancient protaxis along the Sierra Nevadas, the Cascades of Oregon and Washington, and the ranges of western British Columbia. According to G. M. Dawson,*® the Gold ranges were an old protaxis. This entire region exhibited no ‘known Paleozoic sediments until Carbonic times, and it is represented as land in the author’s map. Cascadia was a bordering positive element, and owing to the pressure and subsidence of the vast Pacific ocean it had at ‘different times been subject to great volcanic activity. The first seismic period was coincident with the late Devonic of California, but during the late Paleozoic and early Mesozoic volcanic action appears to have been as great as in Cenozoic time. Various geologists have included Cascadia in the Rocky mountain or ~Cordilleran land, the southern end of which was pointed out by King;°° Jatterly Willis® has defined this as the Pacific element. Central Newfoundland range-—See Newfoundlandia, under Acadia. 86 Williams: American Journal of Science, vol. 3, 1897, p. 397. See also Willis: Bull. “Geological Society of America, vol. 18, 1907, pp. 394, 398. 87 Von Ihering: Archhelenis und Archinotis, 1907, p. 111. 8 Dana: Bull. Geological Society of America, vol. 1, 1890, p. 45. 82 Dawson: Ibidem, vol. 12, 1901, p. 84. *% King: U. S. Geological Exploration, 40th Parallel, vol. 1, 1878, p. 247. *1 Willis: Bull. Geological Society of America, vol. 18, 1907, pp. 396, 398. 470 C. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA Cincinnati axis——This is represented by the Cincinnati geanticline of Dana,®? or the Cincinnati uplift of earlier geologists—Newberry and Saf- ford—and the Cincinnati plateau of Williams.** This low parma had the strike of the Appalachian folds and was at times overlapped by the sea, in which case either end, or both, may have persisted as islands. The northern portion will here be referred to as Oincinnatia (Cincinnati island, Dana*®*) and the southern end as T’ennesseia (Tennessee island, Dana). The uplift appeared in middle Ordovicic times, and was a marked topographic feature of the Mississippian sea since that time. Cin-- cinnatia may have been completely submerged in early Mississippic time, since which it has been land continuously, and today has greater elevation than at any period of the Paleozoic. Columbia.—The government geologists of Mexico believe that most of their republic was land during the Paleozoic, for such strata occur only along the southern boundary in Chiapas, more extensively along the northern limits, and especially in Sonora. Most of Mexico is deeply buried beneath Mesozoic sediments, and it is in the south and west alone that the metamorphic formations of supposedly pre-Paleozoic age appear at the surface. During the Paleozoic this republic extended northeast- ward through the Llano region of Texas into Louisiana and Arkansas. To this “rather neutral element” may be applied the term Liano of Wil- lis.°° Columbia is often continued as an unbroken land far to the north, then embracing part or all of Siouxia. Ensenada.—The history of southern California, northern Baja Cali-- fornia, and western Arizona is very obscure, but geologists surmise that this region was land throughout the greater part of the Paleozoic and possibly until the Pennsylvanic. The elemental name is taken from the town of Ensenada de Todos Santos, Baja California. Franklima.sSee Laurentia. Greenlandia.—See Laurentia. Honduria.—A very persistent positive pre-Paleozoic element, the nu- — cleus of which is Honduras. Its geological history seems to be connected with that of Antillia. To the north, in Guatemala, both Paleozoic and Mesozoic strata have been found, while to the south, in Nicaragua, Meso- zoic and probably Paleozoic sediments are reported. Kankakewa.*"—A low, irregular parma trending “northeast from south— — °2 Dana: Bull. Geological Society of America, vol. 1, 1890, pp. 41, 42. 93 Williams: American Journal of Science, vol. 3, 1897, p. 394. *4Dana: Manual of Geology, 1895, pp. 537, 633. ®5 Schuchert in Eastman: Ann. Rep.’ Geological Survey of Iowa, vol. 18, 1908, map.. % Willis: Bull. Geological Society of America, vol. 18, 1907, pp. 394, 397, 398. ®*7 Schuchert: American Geologist, 1903, p. 150. POSITIVE ELEMENTS Avian ern Illinois to the region of the Kankakee river . . . striking north- erly through the western part of the lower peninsula of Michigan.” It also seems to have originated with the movements recorded in the T’aconic revolution, and this parma is often in connection with Missouria. Keewatinia.—See Laurentia. Keweenaw continent.—Walcott®® proposed this name in 1886 “for the land that existed on the North American continental plateau at the begin- ning of Cambrian time.” “The name is now adopted for the continent at the beginning of Cambrian time.” Laurentia.— Frankfurt and Pulaski of New Work: Economy zone, 80 feet. . Ordovicic. Fulton (= Utica), 5 feet. McMicken zone, 60 feet. Edenian....... The Ordovicic period was closed by the Utica emergence. As has been seen, this emergence was widespread, and even the greater part of the early Utica sea was finally eliminated. This condition apparently con- tinued into the Lorraine. If the necessary maps could be made, however, it is thought that the paleogeography would show either a stationary or a slightly enlarged sea during the Frankfurt and Lorraine, this having | been brought about by the Taconic revolution of long duration in the Appalachian region. It began in the Trenton and persisted nearly to the close of the Cincinnatic, during which time the older Paleozoic strata were folded all the way from southern Virginia to Newfoundland. In this eastern region, therefore, the life of the later Utica, Frankfurt, and Lorraine was greatly affected not only by the large influx of mud and sands, but even more by the shallowing of the Appalachian waters. In the northeast, in the Saint Lawrence sea, these effects were perhaps more - pronounced than in the Appalachian trough south of New York. West of the Cincinnati axis, all of America was elevated above the sea during the Utica, Lorraine, and earliest Richmondian, but in later Rich- mondian time there was again widespread submergence. Nearly all of the Utica is absent at Cincinnati and to the south, but to the north the deep- well borings show more and more of this formation. With the Edenian, which also includes the Frankfurt of New York, the sea again returned to the Cincinnati area, and this invasion is thought to have marked the be- ginning of the Cincinnatic period. To the east of the Cincinnati axis the Appalachian sea was fairly constant in areal extent to the close of the Lorraine, when more and more of the marine waters here subsided. In the Cincinnati region, the Maysvillian sea was apparently continued with- out break into that of the early Richmondian. This sea then spread west of the axis and united with the widespread flood of the later Richmond, which came in from the Arctic and Pacific areas. In extent this trans- gression stands second in comparison with that of the Trenton sub- mergence. On faunal grounds there is decided evidence for placing the Edenian and Maysvillian, together with the Richmondian, in the Cincinnatic sys- tem. ‘These three series are united by about 5 per cent of the fauna that is common to all of them, while of the Edenian species about 14 per cent pass into the Maysvillian, and of the latter about 12 per cent occur in the 532 sc. SCHUCH ERT—_PALEOGEOGRAPHY OF NORTH AMERICA Richmondian (Nickles, 1902). The Edenian and Maysvillian faunas represent the return of the Mohawkian faunas, but somewhat changed. In the early Richmondian, however, there was an influx of migrants from a new area, probably the North Atlantic (Anticosti), forming the Rhyn- chotrema capax and R. perlamellosa faunas. At the close of the Richmondian all further Cincinnatic records of marine deposits are absent in the interior region. The continent remained emergent for a long time, and when the next short oscillations of the oceans occurred the faunas represented are very different, having several spire-bearing brachiopods and other reminders of the Siluric. The dividing line between the Cincinnatic and Siluric is usually drawn at the top of the Richmondian, but this delimitation will now have to be changed, as it fails to recognize a long interval elsewhere recorded. On Anticosti may be studied a complete section bridging this lost interval, and through 1,134 feet of hmestones may be traced the gradual transition of the life of the highest Richmondian into that of the earliest Siluric. The Cincinnatic, therefore, can not be closed with the Richmondian, but must be continued until a considerably later period—one yet to be deter- mined by the Anticosti record. NEOPALEOZOIC ERA Stluric or Ontaric Period See plates 65-71, and pages 489-491 On the basis of their faunas the American Siluric deposits are geo- graphically divisible into three provinces, the best known being that of the Atlantic realm, which is represented on the continent by three sub- provinces—the Saint Lawrence sea, the Appalachian trough, and the Indiana basin of the Mississippian sea. These waterways also have the longest sequence of formations—in fact, showing a nearly complete rep- resentation of the Siluric system. The next best known province is that of the Hudson sea, whose faunas are of Arctic and northern European derivation. This sea appeared in the United States long after the begin- ning of the Siluric and vanished with the Guelph. The third province is that of the Cordilleran sea, evidently Pacific in origin, but of which little is known. ‘The following synopsis of the crinoids, brachiopods, and trilobites will bring out the relationship of the eastern provinces: —E Table of Widely Distributed Silurie Formations (ala) (ae) —$____—______— —_—-— — — — = —_ — — — ————— — ————— = - ie) : e en ees Berles 2 Hast of Cincinnati Hast of Cincinnati wy os CE Cinalanaiu ee ; or Western New York axis. Ohio Bist Isentuley Indiana, Kentucky, Ten- Wisconsin Iowa epochs nessee Break Break Guelph of Ontario Decatur, 63-70 | Guelph feet +S Lobleville, 17—| Racine (Reef Ihe- Break 2 [ 76 feet - stone) Cedarville S a 4 Bob, 15-75 feet | Upper Coral beds, nD S| | 5 | Beech River, 37— 75 feet A aa [ 101 feet Break a a = | Dixon, 18—44 | Lower Coral beds, Bertram. Coggan = | Lockport, 130 feet 4 feet 70 feet = 2 Springfield Lego, 25-46 feet) Byron, 140 feet : Anomosa, 60 feet Bs 7 Waldron, 2-9 ® Le Claire (Reef cz, feet 5 : limestone), 80 s ; nine Laurel, 25- Cl feet ma Rochester, West Union ; ; 33 feet Maryville, 15-57 Hopkinton, 200 2 85 feet Same | Niagara shales, 50-100 Alger, 83-143 feet Saint Clair Osgood, 10— feet feet = Irondequoit, fauna ‘feet 22 feet RD 14 feet Dayton Indian Fields, 15-20 Break Break Break feet = bi Williamson, ©) 6 24 feet a q a as Wolcott (Fur- Break Break Break 8 S oe naceville), 2,3| Aa 14 feet Zoos = \ Sodus le ae) Small break Ohio Clinton, 20-150) Brassfield, 13-19 feet Ohio Clinton, 0—20 feet Ass Medina feet Edgewood, 0-4 feet (Oneida) Girardeau, 0—40 feet Break 534 ©c. SOHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Of crinoids, Weller*®? has determined that the following genera of northwestern Europe are also present in the Chicago area (northern Illi- nois, southeastern Wisconsin, and Iowa), but not elsewhere in the United States: Botryocrinus (1 species), Corymbocrinus (2), Crotalocrinus (1), Marsupiocrinus (1), Melocrinus (1), Petalocrinus (2), and Pycnosaccus (1). As crinoids are very sensitive to environment and change. rather rapidly, this list is proof of direct migration from Europe. Further, in the same area occur other genera that are found elsewhere in the United States. These are: Callicrinus (New York and Tennessee), Hucalypto- crinus (widely distributed), Gazacrinus (widely distributed), Ichthyo- crinus (New York), Lecanocrinus (widely distributed), Lyriocrinus (widely distributed) , Myelodactylus (New York and Tennessee) , Periecho- crinus (New York and Tennessee), and Thysanocrinus (New York and Tennessee). But few of the species are common to two areas. In other words, the majority of these crinoids are of one province—that of the Hudson sea and the Arctic realm. The genera comprising the second lot are more widely distributed, geologically and geographically, and are com- mon to the Arctic and Atlantic realms. y The crinoid genera of the New York basin are also common to the area west of the Cincinnati axis and south of central Indiana—that is, the Indiana basin. These are: Calceocrinus (not in the Chicago area), Callt- crinus, Eucalyptocrinus (a few species are common to the two areas), Euchtrocrinus (not in the Chicago area), Gazacrinus, Homocrinus (not in the Chicago area), Ichthyocrinus, Lecanocrinus, Lyriocrinus, Macro- stylocrinus (widely distributed in America), Mariacrinus (not in the Chicago area), Myelodactylus, Periechocrinus, Pisocrinus (not in the Chicago area), Stephanocrinus, and Thysanocrinus. In other words, these crinoids are of one province—that of the Mississippian sea—and belong directly to the Atlantic realm. Further, 5 genera of the Missis- sippian province do not occur in the Hudson province, and 7 genera of the latter area are unknown in the southern region. At present the corals of the Siluric have little stratigraphic value. They begin to be common in the Rochester, from thence up to the Guelph reefs occurring at different horizons, and judging from published lists are about the same throughout. This is especially true of the Mississip- pian and Hudson seas. Corals are never abundant in the Saint Lawrence sea except on Anticosti, where the small reefs appear earlier than any of those in the Mississippian sea. ‘These forms are now being determined at Yale. 158 Weller: Bull. Chicago Academy of Sciences, vol. 4, 1900, pp. 1-153. SILURIC OR ONTARIC PERIOD DOD Many of the Siluric brachiopod genera of America also group them- selves readily into two distinct realms—the Arctic and Atlantic. ‘To the Hudson sea are restricted the following genera: Capellinia, Orthotropia, Dinobolus, Monomorella (both occur in the Saint Lawrence sea), Rhino- bolus, and Trimerella. It is very significant that all the platform- bearing oboloids are of the Arctic realm or of northern Atlantic waters. In the three continental seas having Atlantic connections—the Saint Lawrence, Appalachian, and Mississippian—there are many genera re- stricted to these areas, most of which are also represented in Europe. These are: Anabaia, Anastrophia (may have representation in the Hud- son sea), Atrypina, Delthyris, Dictyonella (may be in the Hudson sea), Gypidula, Hindella, Homeospira, Hyattella, Mimulus, Orthostrophia, Reticularia, Scenidium, Streptis, Stricklandinia (out of 16 species, only 2 in the Hudson sea), and Uncinulus of the stricklandi type. The trilobites are usually excellent indicators of provincial connections, and as those of the American Siluric are practically all in harmony with those of western Europe, it must be assumed that the Atlantic has been the realm where these forms have developed. They are also good travel- ers, for Van Ingen has identified three European species in Arkansas— Acidaspis quinquespinosa, Deiphon forbest, and Staurocephalus murclhi- som. Further, of the 105 American Siluric species listed by Weller (1907), at least 17 have a wide geographic range and occur in two proy- inces. The trilobites as a rule, therefore, appear to have a long range in time, certainly longer than the crinoids, but are not so persisting as the brachiopods. During the time of the Clinton and early Rochester, a series of migrants from the permanent basin of the Gulf of Mexico appear in the Mississip- pian sea on the west side of the Cincinnati axis. Many of these trilobite genera also occur in Europe, and later find their way into the province of the Hudson sea. These are, according to Weller (1907): Actdaspis, Ampyzx (restricted to the waters of the Gulf), Arctinurus, Ceratocephala, Ceraurus, Corydocephalus, Cyphaspis, Dalmanites, Deiphon, Dicranopel- tis, Encrinurus, Metopolichas, Odontopleura, Phacops or Acaste, Proetus, Spherexochus, and Staurocephalus. Other and northern Atlantic genera are: Bronteus and Homalonotus. Still later migrants restricted to the Hudson sea are: Harpes and Illenus. In the Chicago area Weller has described 12 species of the last named genus, and there are 2 other forms from the same province. In other words, of the 17 American Siluric species of J//enus, 14 are found in the area of the Hudson sea. The known trilobites of the American Siluric are, therefore, of the Atlantic and Arctic realms. The great majority of genera, however, are XLVII—BuLuL. Grou. Soc. AM., Vou. 20, 1908 536 GC. SCHUCHERT—_PALEOGEOGRAPHY OF NORTH AMERICA from the southern waters of the Atlantic, and many of these also find their way into the northern waters of the Hudson sea. _ Saint Lawrence sea.—On the island of Anticosti, in the Gulf of Saint Lawrence, there is a complete transition from the Cincinnatic into the Siluric. The line of division between these two systems must here at least ever be an arbitrary one, the determination of which is now being worked out at Yale. On Anticosti the Siluric apparently terminates near the base of the Rochester. Many of the species of this area are not only European in aspect, but are also found in the Clinton formations of the Appalachian trough. Another fine, even longer, but far less fossiliferous section is that of Arisaig, Nova Scotia, recently restudied by Twenhofel*** and the writer. This succession of faunules, while clearly of European affinity, differs markedly from all others of the Saint Lawrence sea, a condition probably due in part to the rapid accumulation of muds and sands in this area, and also to different sea ways. Farther to the northwest, in the Bay de Cha- leur, at Black cape, near Richmond and about Port Daniel, may be studied other long sections of the Chaleur group, which continue the Anticosti section certainly as high as the Guelph. Some of these fossils have been described or listed by Billings. Near Dalhousie, and again about Gaspé, may be seen the beds that continue into the Helderbergian, but unfortu- nately they are almost unfossiliferous. Acadian trough.—Faunas similar to the foregoing, but far more sparse in species, are also known in eastern Maine, buried in a vast mass of vol- canic material said to attain a thickness of 46,000 feet. Among others, here occur the two European guide fossils Conchidium knighti and Car- diola interrupta. In folio 149, U. S. Geological Survey, is described the Ames Knob for- mation of Penobscot bay, Maine, which has a thickness of 580 feet. The fauna was first listed by Beecher, and the list, somewhat changed, is re- peated here. It contains Clinton forms in the lower half of the series, while the upper portion has a fauna typical of the Rochester shale. Vol- canic activity had begun in this area at this time, since two of the red shale beds are composed of volcanic dust. Appalachian trough.—Very similar faunas are again seen in the Appa- lachian trough extending from central New York into Alabama. En- trance from the Atlantic was effected in two places: in the north across New Jersey and in the south by way of the Gulf of Mexico into Alabama. These biota are as yet very imperfectly known, but have been described in 154 Twenhofel: American Journal of Science, vol. 28, 1909, pp. 143-164. SILURIC OR ONTARIC PERIOD Sear part by C. A. White, Foerste, Prouty, and Ruedemann. The earliest Silu- ric fauna of this trough is contained in the fossiliferous Upper Medina, 120 feet in depth, as exposed in the Niagara River gorge. The more im- - portant fossils are: Arthrophycus harlani, Dedalus archimedes, Helopora fragilis, Lingula cuneata, Camarotechia cf. neglecta, Whitfieldella oblata (these shells are of large growth and far too large to be of Cincinnatic age), Modiolopsis orthonata, M. primigenius, Pleurotomaria (?) perve- tusta, P. (?) littorea, Bucanopsis trilobatus, and Isochilina cylindrica. At Hamilton, Ontario, less than 40 miles from the Niagara gorge, asso- ciated with these fossils in this horizon are others that are clearly Clinton ~ species. This is best shown in the Bryozoa. These strata, and those of Dundas and Flamborough Head, are usually referred to the Clinton, but in the field hold the place of the Medina. In Pennsylvania, Maryland, and Virginia the equivalent horizon is the Tuscarora, or White Medina, sandstone. Ulrich refers the Medina to the Cincinnatic, yet to the writer this fauna seems distinctly younger than anything he has seen referable to the later Richmond. It is very closely related to the Clinton. On the other hand, if the additional fossils listed by Grabau?®> have been acquired by him, there can be no doubt of the Siluric age of the Medina sandstone. The next higher formation of this trough, the Clinton, is marked by: Paleocyclus rotuloides, Monograptus clintonensis, Retiolites genitzianus venosus, Anoplotheca hemispherica, Pentamerus ovalis, Stricklandinia lens, S. saltert, S. davidson, Brachyprion corrugata, Chonetes, Cornulites, Beyrichia lata, and Calymmene clinton. The higher Niagaran strata are marked by Atrypa reticularis, Reticu- laria bicostata, Spirifer crispus, Homeospira evax, Camarotechia obtusi- plicata, Dalmamites limulurus, and Homalonotus delphinocephalus. Mississippian sea.—On the west side of the Cincinnati axis, in the Indi- ana basin, appear the earliest Siluric deposits of the Mississippian sea, which were first pointed out by Ulrich and Savage.°* The faunas are clearly of Atlantic origin. In southwestern Illinois, above the Cincin- natic deposits, occurs the Girardeau, with Rafinesquina mesacosta, Lep- tena rhomboidalis, Schuchertella missouriensis, Rhynchotreta, Homeo- spira, Cornulites tenuistriata, C. incurvens, Platyostoma, Strophostylus, Acidaspis hallr, Cyphaspis girardeauensis, and Encrinurus. A little higher is the Edgewood zone, with new additions, as Atrypa rugosa, A. putilla, Hindella, Whitfieldella billingsana, Clorinda, Platystrophia, Schuchertella subplanus, Dalmanites dane, and Lichas breviceps clinto- 155 Grabau: Journal of Geology, vol. 17, 1909, p. 238. 1456 Savage: American Journal of Science, vol. 25, 1908, pp. 431-443. Ibidem, vol. 28, 1909 : 516-519. See 5388 ©c. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA nensis. This is followed by the Ohio Clinton horizon of wide extent, from Oklahoma to Ohio, marked by Triplecia ortoni, Stricklandinia triplesiana, Atrypa marginalis, Orthis flabellites, Plectambomites trans- versalis, Rhinopora verrucosa, Phenopora magna, Pachydictya bifurcata, Favosites favosus, Halysites catenulatus, Stromatopora, etc. In the Anti- costi section it is seen that this so-called Clinton, or the Triplecia ortom zone, is older than the true Clinton of the Appalachian region. The older Clinton, therefore, is here mapped as the Ohio Clinton. Ulrich has discovered that in northeastern Alabama this same fauna underlies the Appalachian Clinton with the Anoplotheca hemispherica fauna. These are the early Siluric faunas of the Gulf region, the first oscilla- tions that finally terminated in the Louisville transgression. In the earliest stages of this transgression not more than 6 per cent of the North American continent was covered by the continental seas, and about 12 per cent of the United States. At the height of the invasion about 36 per cent of both areas was inundated. The waters finally receded somewhat beyond the stage represented at the opening of the Siluric, for Manlius time shows the figures to be 5 and 10 per cent respectively for the two areas above mentioned. The various formations that record this transgression first appear in the Mississippian sea, and later in the Hudson-Arctic sea. They are arranged in the Siluric table. The Guelph faunas are distinguished from those of the Louisville and equivalent horizons by an almost complete absence of cystids and crinoids. The corals are scarce and are of the genera Favosites (3 species), Syringo- pora (1), Halysites (2), Heliolites (1), and Stromatoporoidea (6). Of brachiopods, practically no other forms are found than T’rimerella (5 spe- cies), Rhinobolus (2), Monomorella (6), Pentamerus oblongus, Con- chidium occidentale, and Clorinda ventricosa. The guiding pelecypod is Megalomus canadensis. The Guelph is especially distinguished by gas- tropods, of which there are more than 50 species. Many of these are large and nearly all are thick shelled. Of nautiloids, there are at least 20 species belonging to genera known in the Racine. Large Leperditia are also present. The trilobites are not conspicuous, and Hurypterus is rare.°" Cayugan emergence.—The Niagaran transgression attained its maxi- mum spread toward the close of Louisville time. Early in the Guelph the sea began to retreat, first in the Appalachian trough and next in the Indiana basin, where the Decatur is thought to be of this time. A little 137 Whiteaves: Paleozoic Fossils, vol. 4, 1906, and Clarke, Memoir no. 5, New York State Museum, 1903. SILURIC OR ONTARIC PERIOD 539 later a general subsidence was in progress in the Hudson sea, and finally the greater part of the American continent became emergent. ‘This was at the beginning of the Salina group, and from this time to the close of the Siluric the continental seas were North Atlantic in origin, their extension being restricted to the northern Appalachian and the Saint Lawrence seas. The seas of Cayugan time in the main were not normal marine waters. They were shallow pans, in which locally red and black shales, with salt, gypsum, and water limestones, were deposited. The life was Atlantic in origin, the principal eurypterids and ceratiocarids having marked rela- tionship with those of Scotland and Wales, and to a lesser degree with | those of the Baltic area. Even in the Saint Lawrence trough, the de- posits of this time are as devoid of life as those of the Appalachian sea. Toward the close of the Siluric in the Monroe group normal marine conditions gradually became dominant, and there was an appearance of life prophetic of the Helderbergian of the Devonic. The various forma- tions of the Cayugan series are as follows: Table of Cayugan Formations Neg Ons Michigan and western On- tario (Grabau, Jour. Western New York |Eastern New York Geol., 1909) Lucas Manlius, 75 feet | Amherstburg | \ Rondout, 40 feet | Anderdon Monroan Flat Rock Cobleskill, 6 feet erry Monroe group Cayugan Series Bertie, 60 feet Rosendale Camillus, 50-300 feet | Wilbur Syracuse Binnewater Vernon \ 600 et High Falls Pittsford, 20 feet Shawangunk Salina group. | During the Siluric there was much land throughout the Rocky Mountain region, from Mexico into the Arctic area, and it was only on the eastern side of this land that the Pacific spread into the Cordilleran sea by way of the Great Basin and the Arctic ocean. In the Sonoran sea, at Hl Paso, Texas, there was another Siluric transgression. Of these western faunas little is as yet known. Kindle™® reviews all the known Rocky Mountain occurrences. In California a few Siluric fossils have been found in the 188 Kindle: American Journal of Science, vol. 25, 1908. Saas — == ‘on —— es 540 co. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Montgomery limestone.*®® On the lower Ramparts of the Porcupine, in Alaska, Kindle?® reports a dolomite series estimated at 2,500 feet in thickness. The fossils listed indicate Lower Niagaran time. In south- eastern Alaska there is even a thicker series of limestones, with additional argillites that range up into the Guelph.*** Devonic Period See plates 72-77, and pages 491-493 It has been seen that the Siluric closed with most of the North Ameri- can continent emerged. This condition continued with slight marine oscillations throughout the Helderbergian and Oriskanian epochs. Dur- ing these intervals the continent was never inundated more than 9 per cent and the United States 14 per cent. The faunas prophetic of the Devonic appeared in the earliest of these invasions—that is, the Coeymans—and rapidly took on the aspect clearly seen in the later Oriskanian. Late in Oriskanian time the Decewville formation of cleanly washed beach sands, with Atlantic faunas, spread westward through New York into Ontario, and at the same time the Gulf of Mexico embayment, with Brazilian faunas, progressed northward along the western side of the Cin- cinnati axis. This furnished the introduction of the fourth decided Paleozoic inun- dation, which attained its climax in the late Hamilton, and persisted, with a little emergence toward the close of the Chemung, into the Kinder- hookian. In areal extent this submergence was identical with that of the Siluric. The Gulf faunas of Onondaga time are of a more decided warm clear water sea, apparently unrepresented in South America. This sea brought the second widespread coral reefs into the interior region. These reefs are best developed at Louisville, Kentucky; Columbus, Ohio; Onta- rio, and western New York, spreading north into the Hudson Bay region and eastward across the Taconics into the Connecticut trough and the Saint Lawrence sea. Thus the Onondaga is made up of two faunal ele- ments—a larger and dominating biota derived from the south, and a smaller, not especially different element, but well represented by cephalo- pods, from the North Atlantic, together with many Oriskanian descend- ants and some hold-overs. In the area of the Great Basin there is another series of faunas begin- ning with Helderbergian time, and apparently persisting unbroken into 159 Diller: Bull. 353, U. S. Geological Survey, 1908, p. 16. 169 Kindle: Bull. Geological Society of America, vol. 19, 1908. 161 Kindle: Journal of Geology, vol. 15, 1907. DEVONIC FORMATIONS Table of Devonic Formations Series Western New York Hastern New York Gaspé Indiana basin Oklahoma Iowa and Missouri z & (a } Catskill Break & 5 Chemung 4 Powe tance on ee Bedrds L In the main conti- a e. = 2), Cuba Aantal ies ? Woodford State Quarry © I High Point J : eee Portland Oneonta Ss Dunkirk Ohio on) \ iS ee 4 Angola Break 7 | & orrase-") Rhinestreet l tehatel Lime Creek ® | Cashaqua (ie Break a Middlesex 2 Genesee Cedar Valley (Callaway) Tully Tully Probable break Upper Wapsipinicon Ser a = = ys Gaspé — Moscow Mescour | U Marine below,| Sellersburg and Sil- Lower Wapsipinicon PS) Tichenor i continental ver Creek of Indi- (Independence at base) Fe q | Hamilton Canandaigua ) Ludlow- | -lamilton above ana 5 S Centerfield \ ville | Delaware and Olen- Break Break Si lel [ Shaffer tangy of Ohio ® Marcellus (and Stafford) Marcellus Jeffersonville of In- a Ononda Onondaga diana ga | Schoharie Columbus of Ohio Break | Decewville cow. = | of Ontario if Break & Break é J SI Oriskany Oriskany | Esopus Grand Greve Break Ce Gide : 3 S Break Connelley Break o Port Hwen Le} 8 Ss i] : FS E Becraft Cape Bon Ami| Break ; Upper Hunton 3 a Breaks Ae cea \ saint Alban Linden Break Coeymans Break Break a 542 C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA the Mississippian. Though considerable work has been done on these by Hall, Whitfield, and Walcott, they are not at all understood in the light of modern paleontology and stratigraphy. It may be said, however, that these western faunas are not of the same marine province as those of east- ern America. Late in the Middle Devonic the Arctic waters again spread southward, introducing a Euro-Asiatic assemblage of life into the Cordilleran sea. At the close of this epoch this fauna spread through the Dakota sea and connected with the Mississippi basin across Michigan, thus distributing the Hypothyris cuboides fauna into New York. Later in the Upper Devonic the Spirifer hungerfordi fauna is general from California to Lowa, and from Bisbee, Arizona, to Montana. ‘To a limited degree it reaches the Mackenzie basin, and late in Upper Devonic time it extends to central New York. There is, however, another faunal element in the eastern region, best known in central New York, which, through many years of persistent collecting by Clarke, has grown to considerable proportions. This is the biota of the Portage, also known as the Intumescens fauna. In the entire western or Dakota sea there is nothing that can be directly compared with the Portage, while the goniatites and bivalves of the latter formation are in perfect agreement with those of western Germany. Not only has this fauna spread through the New Jersey straits, but also the Spirifer disjunctus fauna of the Chemung, both of which have decided Atlantic and European affinities. The Portage sea deposited a black shale from New York to southwest- ern Illinois, but its waters did not communicate with the Gulf of Mexico. On the west side of the Cincinnati axis, the peculiar fauna is traceable as far south as Louisville and central Kentucky; farther south the sea ap- pears to have been a practically lfeless one. Throughout the Devonic, Appalachia was apparently a low lying land, which, however, was broadly elevated at the close of the Onondaga, as at this time an extensive foreland was added to this positive element. At the beginning of the Hamilton the foreland was largely re-submerged, and if Appalachia was again subjected to movement in this period it was in the southwestern portion, toward the end of Hamilton time, thus cutting off the intercommunication of the Gulf of Mexico with the Mississippian sea. The Acadian positive element, however, was distinctly lifted up, with folding that began late in Onondaga time and persisted throughout the Hamilton and Chemung. It was during this period of elevation that the rivers of this land transported the great masses of muds and sands now piled up in Maryland, eastern Pennsylvania, and New York, having a thickness in places of more than 10,000 feet. Similarly in Gaspé there DEVONIC PERIOD 043 are 7,000 feet of sandstones devoid of marine life, which elsewhere in Quebec contain Old Red fishes, the same types of fishes also occurring in New Brunswick and Nova Scotia. This Acadian highland, with its tur- bid rivers, continued well into Mississippian time. Helderbergian.—In. North America, during the Helderbergian, there were two distinct faunal provinces, an Atlantic and a Pacific. The latter is little known; it was first described by Walcott in his report on the Bureka district, Nevada, but was not distinguished as Helderbergian from the higher Devonic. There is little in this province to suggest the Bohe- mian, or even the eastern Russian Lower Devonic described by Tscherny- — schew. In southeastern Alaska, Kindle*®? has discovered Helderbergian faunas that clearly have Bohemian-Mediterranean connections, as shown in the abundance of Hercynella. It is probable that these Alaskan waters had direct connection with those of the Arctic ocean, for at capes Frazier and Leidy among other forms occur Anoplotheca concava, Spirifer per- lamellosus, Stropheodonta beckw ?, and Strophonella headleyana. At cape Chidly, Labrador, Low has recently collected Gypidula galeata and the very diagnostic Leptenisca concava. Helderbergian faunas are known in the Saint Lawrence trough on Gaspé peninsula; at Dalhousie, New Brunswick; northern Maine, and on Saint Helens island, opposite Montreal. The earliest of these faunas much remind one of those of the New York basin, but the higher elements on Gaspé and at Dalhousie pertain to a distinct subprovince. The Syiri- fer macropleura fauna does not seem to have penetrated beyond Square lake, Maine. These northeastern Lower Devonic faunas are described in detail by Clarke,1®* one volume having appeared in 1908, another in 1909. In their typical development the Helderbergian faunas occur in the New York basin, and were described many years ago by James Hall. These faunas can be traced in the Appalachian trough as far south as cen- tral Virginia, and must have entered this basin by way of the New Jersey straits. The same fauna, but slightly changed, is again met with on the west side of the Cincinnati axis, first in southwestern Illinois and then across the Mississippi river in Missouri. In western Tennessee it is well developed as the Linden formation, and the identical fauna is again found in the Hunton deposits in the Arbuckle mountains of Oklahoma. This southwestern Helderbergian life of Gulf derivation practically coincides with that of New York, and both belong to the southern Poseidon realm, connecting with Bohemia and the Mediterranean. 162 Kindle: Journal of Geology, vol. 15, 1907. 168 Clarke: Memoir no. 9, parts 1-2, New York State Museum, 1908, 1909. 544 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Oriskanian.—In the eastern region of the Appalachian trough, from Maryland to southern New York, the Helderbergian appears to pass with- out break into the Oriskanian. The faunas are still of the southern Atlantic type and are unknown in other areas. Gradually they change into the typical. Oriskany element, characterized by Hipparionyx proxi- mus, Spirifer murchisont, and Rensseleria ovoides. These pertain to a northern invasion, also well known in the Saint Lawrence sea at many localities. Clarke has termed it the Coblenzian invasion, because of its relationship to this northern European Lower Devonic series. While it is well developed in the Saint Lawrence trough, the best American devel- opment occurs in the Grand Greve limestone, where the longest sequence of Paleodevonic formations in America is found. On the west side of the Cincinnati axis a very different late Oriskanian biota is preserved in the Camden, which extends from southwestern Illi- nois throughout western Tennessee. This, the Amphigenia fauna, has many characters in common with the Mecuru of Brazil, and forms the introductory one to the later Onondaga. In the Cordilleran sea Oriskanian faunas are unknown, though some deposits there are regarded as probably belonging to this time. Erian.—In eastern North America there were two distinct subprovinces of the Middle Devonic that at different times were variously interblended. The Gulf invasion, first seen in the Camden of late Oriskanian time, con- tinued unbroken into the Onondaga or Jeffersonville in southwestern I1li- nois. This was the southern element that introduced the widespread De- vonic coral faunas, and as the invasion extended around the northern region of the Cincinnati axis, it blended with the other invasion from the North Atlantic. The latter represented the Oriskanian-Schoharie element, and together with the southern invasion furnished the later Onondaga or early Erian faunas that spread as far north as James basin. West of the Indiana basin there are no deposits of this time except in the Great Basin of Nevada. Walcott has described the latter in his volume on the Eureka district, but the species need revision to accord with present knowledge. To the writer, the Great Basin and the Mississippian sea appear to have almost nothing in common. Before the close of the Onondaga the intercommunication between the New York basin and the Saint Lawrence sea was permanently destroyed. Subsequently the Appalachian sea intermittently received migrations from the middle Atlantic through the New Jersey straits. These addi- tions are most noticeable during the Hamilton, Tully, Ithaca, and Che- mung. Every now and then the Tropidoleptus carinatus fauna of the Atlantic swarmed into this trough, but did not make much progress in DEVONIC PERIOD 545: the Mississippian sea. Here the Gulf faunas persisted in considerable purity, and migrated around the Cincinnati axis into the western part of the New York basin. New York state preserves the best record of these eastern or Atlantic forms and the southwestern or Gulf waves of migrants. Some of the characteristic species of the New York Hamilton, however, appear somewhat earlier in the Jeffersonville limestone of the Indiana basin. In the Cordilleran and Dakotan seas there is no evidence of Middle Devonic faunas until near the close of this epoch. In the Manitoba re- gion then occurs the Stringocephalus burtim fauna in the Winnipegosan series, which in Europe is found toward the end of the Middle Devonic. The same brachiopod is-also found in southern Minnesota, in red residual clay or geest. In Iowa the lower Wapsipinicon may belong to this time, yet its fauna, though meager, seems to be rather of the early Upper De- vonic type. Neodevonic.—Toward the end of the Middle Devonic the Gulf embay- ment became closed, and about this time there appeared in Iowa a west- ern fauna, that of the Cordilleran sea, which spread to the Kankakee axis and through the Iowa and Traverse basins, connecting with the Mississip- pian sea. However, it does not yet appear that much of this western life invaded the eastern sea at any time during the Erian, Senecan, or Chau- tauquan. Clarke thinks that the strange and decidedly European Portage or Intumescens fauna migrated from the Cordilleran sea into the New York basin, but to the writer its path seems to have been from the Atlan- tic through the New Jersey strait. These forms may have distributed themselves along the Atlantic shore of Appalachia into the Appalachian trough, thence south to the shallow region of Virginia, then across to the eastern shore of Alleghania, and so north into western New York. If this path is not admitted to be the true one, the reverse must have taken place, in which event the Intumescens goniatites came to New York from the Cordilleran sea, developed in great generic and specific variety in the western New York basin, and then migrated into the Atlantic and across to Europe. It is hardly probable that the same genera developed twice from the same primitive stock, both in New York and western Europe. The Appalachian trough served as the means of continuing the Atlantic Hamilton faunas into the Ithaca and Chemung, and throughout this time the New Jersey straits were open. In the northeastern end of the trough the normal marine conditions gave way to vast estuarine flats of red muds, while the Ohio and Indiana basins had mainly changed to black seas, owing to the cul-de-sac condition of this area. For these reasons the 546 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Neodevonic faunas of eastern America are varied, and are not nearly so uniform in composition as those of the Hamilton. In the Cordilleran sea within the area of the United States, from Ari- zona (Martin and Lower Globe formations) and California (Kennett formation) east to Iowa, occurs the Lime creek or Spirifer hungerfordt fauna, clearly of Kuro-Asiatic derivation. In the Manitoba region, Tyr- rell has collected and Whiteaves has described a late Mesodevonic fauna characterized by the well known European Stringocephalus burtimi. It is their Winnipegosan biota, together with Neodevonic forms, as Gy- pidula comis, Pugnus pugnus, and Stropheodonta interstrialis. This dolo- mite, 100 feet in depth, is followed by the Manitoban limestone and shale (with brine springs), 200 feet in thickness, apparently equivalent to the Lime creek of Iowa. The Manitoban fauna is widespread in Alberta, Athabasca, Mackenzie, and Yukon regions, extending to the Arctic ocean. It was first described by Meek, and has since been revised by Whiteaves. | In these northern areas some salt and more gypsum are present. Another late Devonic fauna with a peculiar and distinct aspect is that of the Lower Ouray of Colorado, described by Girty, and very recently by Kindle. The youngest of the western Devonic horizons appears to be the Three Forks shale of Montana, described by Peale. The lower 70 feet of shale and argillaceous limestone have no fossils, but are followed by about 30 feet of green, black, and argillaceous shales crowded with Upper Devonie fossils, of which Spirifer whitneyi is the most common. Recently Raymond*® has described the faunule from the lower beds of the upper Three Forks shale, of which the following are the more characteristic forms: Camarotechia contracta, Leiorhynchus mesacostale, Spiifer pimonensis, Cleiothyridina devomica, Locopteria holzapfelr, Platyclymenia americana, P. polypleura, Prolobites simplex, Tornoceras crebsiseptum, and T. doug- lassi. At the top of the Three Forks, and beneath the Madison, occurs a “yellow laminated sandstone 25 feet thick” (Peale), having a very differ- ent fauna. ‘This was shown the writer by Raymond. Among the fossils Syringothyris carteri and Spwifer cf. striatus are prominent. This fau-— nule is to be compared with that of the lower Louisiana limestone of Pike ‘county, Missouri. Therefore there is here, as in the Mississippi valley, a break in deposition clearly distinguishing the Devonic, both physically and faunally, from the Mississippic. The Alaskan Devonic has been described by Kindle.1® 164 Raymond: American Journal of Science, vol. 23, 1907. Annals of the Carnegie Museum, vol. 5, 1909. 165 Kindle: Bull. Geological Society of America, vol. 19, 1908. Journal of Geology, ~vol. 15, 1907. MISSISSIPPIC PERIOD DAT Mississippic Period (new emendation)*° (Lower Mississippian or Kinderhook and Osage of geologists) See plates 78-80, and pages 494, 495 The extensive inundation of the Middle Devonic was maintained to the early Upper Devonic, and was followed by an emergence of seemingly small extent. The retreat of this water was most marked in the region along the eastern side and the northern part of the Cordilleran sea, where it may have represented as much as 10 per cent of the previous inunda- tion, but in the United States it does not appear to have been greater than from 5 to 9 per cent. In other words, the Devonic was not closed by a very decided emergence, as was the case in most of the previous periods. For this reason the faunal changes in the Cordilleran sea are thought to have appeared slowly, and were not of a marked character. In the area of the eastern United States, however, the physical changes were far more decided, owing to the filling up of the northeastern marine basins toward the close of the Devonic and the local emergence in progress in that region. Toward the close of the Keokuk the period terminated by considerable emergence in all the seas, but more especially in the Cordilleran sea, which appears to have been completely blotted out toward the end of the Mississippic. At a few localities in Montana faunas of supposed Saint Louis or Meramec time have been reported, but according to Ulrich some of the fossils are clearly of the Pottsville. These faunas can now be duplicated in Arkansas from horizons of early Pottsville age. Mississippian sea.—In the southern part of the Mississippian sea of late Devonic time the Chemung emergence was continued into the Kin- derhookian epoch. The new or Fern Glen transgression from the Gulf of Mexico began to appear as early as the Bradfordian, depositing the Chat- tanooga black shale with almost no organic remains. This invasion spread north along the Mississippi valley east of Missouria and west of the Cincinnati axis, as far as southern Indiana. This is the southern Kinderhookian of Weller. Finally, late in the Kinderhookian (Fern 166 The more useful references to the literature on the Kinderhook faunas and forma- tions are the following: Weller : Transactions of the Academy of Sciences, Saint Louis, 1899, 1900, 1901, 1905, and 1906. Journal of Geology, 1898, 1901, 1905, and 1909. Iowa Geological Survey, vol. x, 1900. Bassler : Smithsonian Miscellaneous Collections, Quarterly, no. 1814, 1908. Prosser: Journal of Geology, 1901 and 1902. American Geologist, 1904. Girty : Monograph XXXII, part ii, U. S. Geological Survey, 1899. Professional Paper no. 16, U. S. Geological Survey, 1908. Proceedings of the Washington Academy of Sci- ences, 1905. Rowley : Missouri Bureau of Geology and Mines, vol. viii, 1908. Stevenson: Bull. Geological Society of America, vol. 14, 1903. NORTH AMERICA PALEOGEOGRAPHY OF C. SCHUCHERT 54§ STOUTTT] puv AYONJUOY, UW19}S9A OS[’ *° BIINOSSI JO 4svo TLINOSsstyy CUCIPUL puULB AyonjJuey «‘SIxv Tyeuupoury JO SIM SVSUBYIV Usloy}IOU OSTe eiuBA[ASuuO, pure , {BlINOSsI, JO JSOM LAINnOssry, | S9MIS ‘ BAOT olNO ‘S]XB PeUUPUTD JO 4SVOT ° Bal snsnei i wy Nevis -ey1%9 | © G puvjeadgo yeoig YRorg ¢ YAIVg usp) » o \ os@MSO es a, [ 9u0z a0 ‘Avy ontg a piojpog BMO] JO AVATY YSIsugy —= ddvuy J 4 SIOULTIT jo yooysopuryy ypeordAy, = void yeorg 5 (vruvAlAsuueg Jo La109 G 9u0z 10 ‘snjyoedouoy,) = puew oseMossnyp) BI10G SI — Sassou eal & 9U0Z 10 iS si0qysug (Byoing] =) [VON 8, Aanqung jo Bsoour}} Vy) o | ‘8100 puB s9uUOJSOUIIT BH a (e1uvA[Asuueg JO o{[IA @ pF 9U0Z 10 “BUBISINOTT 5 VUBISINO'T aeg | Q 5 -Suvig) vsoyecny aemory | ry | S g eu0zZ 10 fF \. o 6 |Aurqiy Men aoddy a | ‘euojspues MoTjed Joddy | = jeqruuryy MOTAqVION | & (eruvA[Asuueg JO [IIA B 9 9u0z 10 941100 | § aor yuLEg -sdivyg) esoqednD 2PpI 2 plOFyOO Wy 1 0u0z 10 “e10doydoary st Ud) WAIT UOSIOI =) (viuvaAyAsuued JO o]I[IA | -peoy) esoyqednpg avc0ddy) o000p a U0} SUTLING 1OMOTT UO} SULLAING LOAO'T Ayonj Uy] (etaeAl[Asuued -TAO1d MON S | U19jSoM JO BvVMOyeI[N jo oSuvueyg) pury, :rid ct uo}JSUT[ANg, Lod () uo}Ssurpang teddy, Wis uviyqovieddy ula z (e1ueAl[Asuued S 1 -Y}NOS JO vUAB JO) BUOOG 69 jo o[vys Osuvueys) UBsoOT] SINGSpO11ey YN YOO YU 3OI Sy | 5 (Javd) MBSIBA yvo1g yeoig Yeolg Wvolg yeolg suoynwUMIoy aiddississi py JO 2]Q0,, MISSISSIPPIC PERIOD DAI Glen), the Mississippian sea united across the Kankakee axis with the northern Appalachian waters and the eastern extension of the Cordilleran sea. The faunas of the southern area were derived from the Gulf of Mex- ico, which retained many of the descendants of the previous Hamilton fauna. Other forms are also in harmony with those of western Europe. Toward the close of the Kinderhookian the three provinces, formerly separated, were united, and the Mississippian sea became more general. Weller states: “With the submergence of the Kankakee Peninsula and the partial or com- plete submergence of the Ozark land, the source of the clastic sediments in the immediate Mississippi Valley was removed, and a great period of limestone formation was initiated which is best exemplified in the Burlington and Keokuk formations. The fauna of this clear sea was in large part an outgrowth of the later Kinderhook faunas, and is best characterized by the wonderfully rich [and indigenous] crinoidal element” (1909, 275). The Rockford formation has a fauna of Gulf origin and is marked by the goniatites Prodromites prematurus, Prolecanites greem, P. lyons, Agamides rotatorius, Muensteroceras owen, and M. parallelum. In the Choteau, the following goniatites are also of southern origin: Prodro- mites gorbyi, P. ornatus, Prolecanites gurleyi, Pericyclus blairi, A ganides discoidalis, A. jessiew, and Muensteroceras osagense. The Osagian epoch followed the Kinderhookian, and introduced the widespread Burlington limestone, replete with Echinodermata. In the Paleozoic, starfishes are always rare, and they are so here, but the echi- noids and blastoids are more common. ‘The crinoids, however, are abun- dant and highly differentiated, nearly 400 species being known from the Burlington alone, most of which are found in the vicinity of Burlington, Iowa. This crinoidal assemblage is here indigenous, this being an area prolific in generating crinoids, but in free communication with the Gulf of Mexico and western Europe. “Every genus in the Mountain Lime- stone occurs also in the American faunas . . . ; furthermore, all of those genera which occur in both this Mississippian province and in Eu- rope are represented by a larger number of species in America” (Weller, 1909, 276). The connection is with the Atlantic and western Europe— England and Ireland—but especially with the Tournacien series of Bel- gium, the fauna of which is nearly all derived from the large quarries in the vicinity of Tournai. Above the Burlington is the Keokuk limestone, which in the north and east is more clastic, and often with much shale, but in the south the clear water seas continued, introducing a horde of sharks, as shown by the teeth of these fishes, which are here far more numerous than at any other ip} 5d0 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA geologic age. About 400 species are known in the American “Lower Carboniferous” and about 200 in Europe, most of which occur in the Mississippic. Appalachian basin.—In the northern Appalachian basin the Chemung sea continued apparently without break into the Bradfordian, and for a time maintained connection with the Atlantic by way of the New Jersey straits. After the Bradfordian this opening was permanently destroyed. It is probable that the brachiopods Chonopectus and Paraphorhynchus are of North Atlantic origin, for they occur in the Bradfordian at War- ren, Pennsylvania; later they migrated to Iowa, and there became domi- nant in the earlier portion of the Upper Kinderhookian. In late Kin- derhookian time, therefore, the Mississippian sea had these earlier and independent faunas variously commingled. The Waverly series of the northern Appalachian basin is a continuous one from the Chemung to the close of the Mississippic. Above the Brad- fordian it begins in clastic materials composed of shales, sandstones, and some conglomerates. The faunas are as yet imperfectly known. As Girty has given much time to the collection and study of these forms, his. correlations are here followed, and are given in the table of formations in the column “East of Cincinnati axis” (1905, 5-7). The Marshall series. in Michigan is also representative of this basin and directly associated with the Waverly series, but no attempt has been made to correlate the various beds. It is probable that a part of the Catskill series is likewise of Bradfordian time. In the main these are continental deposits, but they may have zones of estuarine sediments. The Pocono is also Missis- sippic in time, and its deposits, which are chiefly continental with coal beds, may begin as early as the Bradfordian. Cordilleran sea.—The Pacific and Arctic faunas are widespread in the Cordilleran sea. The one best known is the Spirifer centronatus fauna of the Pacific realm in the Madison limestone, which extends to Missouri in the Choteau of Kinderhookian time. In the Yellowstone Park region it persists with little change in the western Cordilleran sea through 1,600 feet of limestones. According to Girty, the Madison occupies the entire time of the Mississippic period as here defined—that is, to the close of the Keokuk. Weller (1909, 282) states that “this fauna shows many affinities with the southern Kinderhook faunas of the Mississippi val- ley’—that is, the Choteau. Girty (1899) reports that 37 per cent of the Madison fauna is common to the two regions. It seems, however, that this intercommunication ceased at the close of the Kinderhookian, as nothing is known of the wonderful Burlington crinoid fauna in the west- ern sea. The life of Lake valley, New Mexico, is now held to be older, MISSISSIPPIC PERIOD 551 and Weller regards it “as a close ally of the fauna of the Fern Glen.” The Madison limestone fauna is known from southern Arizona north to southern British Columbia. Further north the Banff limestone has Mis- sissippic faunas. To the late Kinderhookian of the Cordilleran sea the writer refers also the Upper Ouray, Leadville, and Millsap limestones of Colorado. The lower part of the Red Wall of the Grand Canyon and the Escabrosa and Modoc of Arizona likewise belong here. During the late Devonic the eastern extension of the Cordilleran sea appears to have become land for a time, and this area in Iowa and Mis- souri probably continued into the earliest Bradfordian. ‘The western sea then again extended across Iowa and united with the northern Appa- lachian basin during the time of the Chonopectus zone of the Burlington section. This northern Kinderhookian sea remained unconnected with the Mississippian sea across Kankakeia until toward the close of the Kin- derhookian. In the meantime the eastern extension of the Cordilleran sea was encroaching upon the western side of Missouria, and made con- nection to the south of this land at an earlier date than across the Kanka- kee axis. Saint Lawrence sea—In Nova Scotia, New Brunswick, and New- foundland occurs the very thick Windsor series of variegated marls, sand- stones, and dolomites, followed below by beds of gypsum, marls, sand- stones, and shales. The oldest fauna of this series at Windsor includes but few species, and these remind one of Kinderhookian time. In the higher dolomites at Windsor a rich fauna appears that is very different from that in any American Mississippic horizon, and as it is also unlike those of Europe, it is difficult to correlate. Seemingly it is of Keokuk time, yet may be somewhat younger, as Lithostrotion is reported at Pic- tou, which is not far from Windsor. According to Dawson, the Horton series, consisting of coarse conti- nental deposits, follows below. The plants of this series and of the Albertite beds are regarded by D. White as of late Kinderhookian time. The Bonaventure of the Gaspé peninsula is also of Mississippic time, and consists largely of conglomerates and sandstones, red in color and all con- tinental in character. Arctic regions—In Alaska, on the Porcupine, near the International boundary, Kindle reports Mississippic shales holding a small fauna which Girty believes to suggest “the earliest fauna of the Mississippian.” The few associated plants are regarded by D. White as probably indicative of Kinderhookian time. Brooks and Kindle state that there may be no break here between the Devonic and the Mississippic. XLVIII—BULL. GEOL. Soc. AM., Vou. 20, 1908 7 i 552 = Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA In the Arctic archipelago there is no clear evidence of Mississippic faunas, yet on Feilden peninsula (latitude 82 degrees 43 minutes) species are cited suggestive of this time. The evidence for the Tennesseic and Pennsylvanic is much stronger. According to D. White, the plants of the lower coal beds about cape Lisburne, Arctic Alaska, indicate the Mississippic and of a time “slightly younger than the Ursa flora.” Above is a marine series with corals, rather suggestive of the early Pennsylvanic. Tennesseic Period (new: Ulrich) (Upper Mississippian or Saint Louis and Chester of geologists) See plates S81. 82, and pages 495, 496 The emergence at the close of the Mississippic blotted out the Cordil- leran sea of wide extent, and no deposits of Tennesseic age are as yet defi- nitely known here except possibly in the Arctic region. The Baird or Pro- ductus giganteus fauna is referred to the Pennsylvanic. The best known area of Tennesseic sediments is that of the Mississippian sea, where the greatest thickness is apparently not in excess of 1,200 feet. It is probable that in no part of the latter sea did its waters persist from the Mississippic into the Tennesseic, yet apparently the Keokuk emergence was of very short duration. With the introduction of the Saint Louis transgression much change in the life took place. The crinoids no longer are present in vast numbers and species; the echinoids (Melonites) are much larger and dominate the Meramecian ; Pentremites was previously of rather rare occurrence, but now becomes more abundant and larger and is one of the dominant types of invertebrates, especially in the Chesterian; the Bryozoa of the family Fenestellide, having thickened supporting parts, as Archt- medes and Lyropora, are prolific in numbers and species, especially in the Chesterian. Of brachiopods, Cleiothyridina, Eumetria, and Dielasma are dominant, large spirifers like S. logani are absent, while Athyris, -~Camarophoria, Chonetes, and Syringothyris are rare or wanting. Among the corals, Lithostrotion, or rather, Avinura, apparently originates here; certainly those with large corallites begin at this time and are dominant in the Meramecian. The emergence terminating the T’ennesseic was a complete one in the area of the Mississippian and Appalachian seas, while that of the Cordil- leran sea was absent throughout this period. In the Oklahoma basin, however, the Chesterian sea may. have continued unbroken into the Potts- villian. It also seems to be true that the seas of Pennsylvanic time appeared somewhat earlier in the Cordilleran and Californian than in the 509 TENNESSEIC FORMATIONS Table of Tennesseic Formations Mississippi valley east of South of Appalachian area Seri Missouria. Western West of Cincinnati axis, | Mast of Cincinnati Missouria. eries = : 3 z Iowa Ikentucky. Indiana axis, Ohio Northern Ulrich Arkansas Northern area Southern area Break Break Break Birdsville Birdsville (= Huron) Pitkin Mauch Chunk ) at IKKaskaskia ; ‘i ‘ : 5 Tribune 600-880 feet Break Break Vayetteville Ins} a Cypress Maxville limestone | Batesville Greenbrier ~ DM = Break Break Break Pennington Pella Ohara Verdi St. Genevieve Rosiclare 140-245 feet (Princeton) Fredonia Break Springvale Saint Louis, 300 + feet Mitchell Break q S Spergen, up to 100 feet. |Spergen (= Salem, Bed- © (Includes upper beds of ford), 5-100 feet a the Warsaw of Hall. Newman a See Weller, 1907) a Break Break 554 coc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA two eastern seas. In the Saint Lawrence sea there is almost no evidence for the presence of Meramecian deposits and none at all for the Ches- terian. Mississippian sea.—The best general account of the successive sedi- ments of this sea in the area of its longest development—that is, western Kentucky and southwestern Illinois—is that of Ulrich." This succes- sion is given in the column “Mississippi valley east of Missouria,” in the table of formations belonging to this period. The Upper Warsaw1*®* (= Salem or Spergen), a rather limited forma- tion, introduces the Meramecian, and many of its fossils are continued into the higher horizons. Hall described the fauna in 1858,1®° the more characteristic forms being Zaphrentis spinulifera, Archimedes worthen, Pentremites koninckiana, Spirifer subcarditformis, S. lateralis, S. sub- equalis, and Bellerophon sublevis. The Spergen oolitic limestone is noted for its dwarfed fauna, preserved in oolites. It was first described by Hall; later by Whitfield. The ear- lest appearance of this fauna was in the Upper Warsaw; it became typi- cal and enlarged in the Spergen; its third occurrence was in the Fredonia (35 species of the second occurrence are here represented), and for the fourth time it appeared in the Tribune (40 of the 70 original species are present). Ulrich has recently discovered the same fauna, greatly dimin- ished, in the Pottsville, and its existence in the Montana-Idaho region, described by Meek, should probably be attributed to the same age. The Saint Louis limestone is usually heavy bedded and gray, with much siliceous matter that is hberated as chert. The guide fossils are Inthostrotion (?) canadense and L. (?) proliferum. Ulrich states that the columella of these forms is not styliform, as in Lithostrotion, and that the species are more nearly allied to Lonsdaleia. Castelnau was the first to describe these corals. His Astrea mamillaris is identified as Fischer’s species, and was obtained on the Ohio river, in the state of Illinois. This is the form that is usually known as Lithostrotion cana- dense. Castelnau’s Axinura canadensis is the form now called L. pro- liferum, it was collected on the shore of lake Saint Claire, Michigan, this fact leading him to call it canadensis. Both of these corals are figured and described by Rominger, who reports them as occurring at Wildfowl bay, Bellevue, and Grand Rapids, Michigan. Under these circumstances the coral now called ZL. proliferum will in future have to be known as: 16? Jlrich: Professional Paper no. 36, U. S. Geological Survey, 1905. 168 Weller: Bull. 8, Illinois Geological Survey, 1907, p. 83. 169 Hall: Geological Survey of Iowa, Paleontology, part ii. 170 Whitfield: Bull. American Museum of Natural History, 1882; republished and ex- tended by Hall in Indiana Geological and Natural History Survey, 1882. TENNESSEIC PERIOD 555 Axinura canadensis (it is the genotype of Castelnau’s new genus Azinura and is the only species referred to it), and the L. canadensis of authors must become Azinura mamillaris Castelnau (not Fischer). Should the two forms eventually be regarded as one species, the name would then become Axinura canadensis. Other Saint Louis guide fossils are Melonites, Archwocidaris worthent, Pentremites conoideus, P. cavus, Dichocrinus simplex, Cystodictya major, Spirifer keokuk litton, and Humetria verneuthiana. The Saint Genevieve is marked by Michelima subramosa, Cystelasma rugosum, Lithostrotion harmodites, Amplexus geniculatus, Pentremites florealis, Platycrinus huntsville, and Pugnax ottumwa. Ulrich gives many other species (1905, 47, 48), but all have a longer range than the Saint Genevieve. According to Weller, the latter was the time of greatest transgression. The Kaskaskia is the chief fossil horizon of the Chesterian. It is marked by Pentremites godom and P. pyriformis (also occurs below), P. obesus, P. forbesi, and P. pyramidatus (above), Agassizocrinus, Ptero- tocrinus (above), many Archimedes, Lyropora, Meekopora, Prismopora serrulata, Spirifer increbescens, Spiriferina spinosa, Cletothyridina roysst, Composita subquadrata, and Humetria vera. As ammonites generally serve as good guide fossils to horizons, it is deemed advisable to give the species found in the Batesville: Gomiatites sphericus and G. striatus (both are European forms). In the following shales, the Fayetteville, occur Bactrites carbonarius, Glyphioceras calyz, Goniatites crenstria, G. newsom, G. subcircularis, and Gastrioceras en- togonum.*"+ Arctic region.—In the Arctic archipelago Lithostrotion has been iden- tified in at least three localities. The associated species, however, do not make it clear whether the horizon is Tennesseic or Pennsylvanic. Coal beds, possibly of early Tennesseic age, occur in many places in the Arctic archipelago and more certainly at cape Lisburne, Arctic Alaska. It is more probable that these faunas are of Pottsvillian age. Pennsylvanic—Permic Period See plates 83-85, and pages 496-498 In North America the Permic was not introduced with a new submer- gence, as was the case in Europe and India; on the contrary, the Pennsyl- vanic transgression attained its maximum spread late in this period, after which there was continuous emergence until the close of the Permic. In 71 Smith: Monograph 42, U. S. Geological Survey, 1903. ~_ — we HH Hi i) tty ty) 506 C. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA other words, in America these periods belonged to one diastrophic cycle. Each part of these movements was of very long duration. From the stand- point of marine invertrebrates, the life of the Permic period—that is, the Permic in the widest sense—was normally developed only in the Trans- Pecos region of Texas. Elsewhere the early Permic waters (Oklahomian) were not normally marine, and therefore retained the hardy Pennsylvanic species, especially the bivalves. Associated with these, however, were a few forms of ammonites, indicative of early Permic types (Artinsk, as this term is now used in the wider sense by most stratigraphers). This was particularly true of the region east of the Mississippi river, while to the west of this stream the Pennsylvanic waters were more often normally marine, followed in early Permic time by an abnormal sea that deposited. over great areas red muds replete with gypsum, some salt, and, locally, dolomites. In the Rocky Mountain area, however, the seas were more nor-- mally marine in the Pottsvillian, and in the early Missourian local eleva- tion and shoaling began, with much accumulation of sands. Later this uplift prevented the eastern waters from mixing with those of the Pacific, — thus causing the latest Missourian faunas to become very different from those of the Mississippi valley. Saint Lawrence sea.—In the maritime provinces of eastern Canada the Pennsylvanic is well developed and usually of very great thickness. The celebrated Joggins section of Nova Scotia is 13,000 feet in depth, and may extend into the Permic. The Cape Breton series is 10,000 feet thick, and the Pictou field has a similar thickness. 'The Riversdale and Harrington river beds and the plant-bearing beds near Saint J eh New Brunswick, are also of Pennsylvanic age. It is very rare that marine fossils are reported from this region, and the few that have been listed indicate Pottsvillian rather than Missouriam time. In the Riversdale has been found Belinurus grandevus, and Ami has shown the writer examples of Huphemus carbonarius and Leaia from: the same beds.*”? Pottsvillian or Lower Pennsylvanic.—There is no system of Paleozoic formations in America in so unsatisfactory a condition for detailed corre- lation as the Pennsylvanic. Probably no other system has received so: much attention, and yet on the basis of marine invertebrates the faunal characteristics distinguishing the Pottsvillian from the Missourian are: still undetermined. It is true that marine life is not generally present in these lower formations; the literature, however, indicates that such forms: have been seen at many localities, but the species are very rarely men- 172 Ami: Annual Report of the Geological Survey of Canada, vol. 12, 1899, pp. 100A- 204A. Table of Pennsylvanic—Permic Formations 557 - } 558 7 ] | = - so ~, re Northern Appalachian. Bituminous. Pennsylyania— Anthracite region, Eastern | 2 an Central Sere West | PP: Ohio eneegivantel Indiana Illinois: Towa and Missourl Kansas (numbers refer to the zones of Adams) Northeastern Oklahoma: Central Texas: ‘Trans-Pecos, Texas » iy * c | 3 * Break Rustler Castile gypsum Capitan Iimestone, 1,800 . Break | Break Break ase g | g 5 —- —= | a 3 i 7 3 eS Be) Break | Absent Absent | Absent Absent salen Kiger Quartermaster 2 as | | | & Cimarron { Sate Fork é Greer. Much gypsum i Double Mountatn 3 Bie | a a |B } Woodward (Whitehorse) Bul eee 5 B3| Dunkard or Upper Barren | 2) pierive {Sumer (Marion) ao47 | g j 24 Clear For o _ oN eon x | Chase Wreford 3 | Blaine Much UNG k Delaware Mountain, 1,500 5 | ©, | S | Enid, 1,500 fect hesortan ATO METS feet 5 | Oe ahi gerne ke ea ao | | = fin : 7 : Neosho | g ae < = Monongahela or Upper Productive Coal Measures Anthracite. Coals A, B, C, Break Break (Top. Cottonwood) Counell Grove (88, 39) cottonwoud | Cisco =| | ali | | $J Hueco Hmestone, 8,000- = Wabaunsee (2 Chandler 8 5,000 fect } g | Biaxton 2 Conemaugh or Lower Barren Upper or Barren Coal Measures Missourl serles | Shawnee (2: Canyon i+} 5 S Ames limestone, near middle. Douglas (19-21) Hominy: eae 8 Ay) Base, Winterset of Iowa Pottawatomie (10-18) | 2 3 Wreeport Coal, No. 6 and Bethany of Mis- Marmaton (2-9) | Marmaton Strawn Bec neeren & | | Allegheny or Lower rami | ||eaavm at | : ho AGNES] Clarfon Lower Coal Measures Coal, No. 2 Cherokee (1) Cherokee Break = Ba pe ee ER: fe is i" a Bo,” ) . Homewood | sap 2) | anew | Des Moines serles } Break | Abaone E | Mereer | | es | Upper Transition series | | ee | | Bend A | Conoquenessing | | Breal | | cI | | 2 | | | Fe - | Sharon | | Break | | = | = | Nuttall z Upper Lykins: Mansfield Coal, No, 1 . = $2} = | Sewell & || Lower ‘Transition : | = || 2 2 = | | i & | Ratetgh Lower Lykins | | | | | | | | Quinnimont Break Break Break | | | | | | Clark | | Pocahontas i | | PENNSYLVANIC—PERMIC PERIOD 509 tioned. The correlations thus far made are based on stratigraphy, ratified by the excellent floral knowledge of David White, which has been pub- lished in a number of papers. The map of Upper Pottsville time is chiefly founded on the evidence furnished by the flora and on certain correlations made by Girty. He states :*‘* “The Pottsville group has a distinct fauna and appreciable changes occur in the later Pennsylvanian. But the changes are by no means so marked as one would be led to expect from the thickness of the strata involved, the extent of - the territory they cover, and the varying conditions of the time and the place.” In the Appalachian region, Girty*™ states that “The Pottsville series is righly fossiliferous in the way of fossil plants, but fur- nishes as a rule few invertebrates. The invertebrate faunas are, except in a few instances, peculiar and restricted, and clearly indicate unusual environ- mental conditions. The most frequent fossil is Naiadites elongatus Dawson, with which are associated bivalve crustaceans, such as Hstheria, Leaia, and Ostracods [also Spirorbis]; while more rarely fragments of Prestwichia, or Limuloids, or fish scales and plates are brought to view. An occasional Pec- tinoid, almost always of the type of Arviculopecten whitei, together, not infre- quently, with Lingula and Orbiculoidea, indicates that these faunas cannot be considered as owing their peculiar facies to strictly fresh-water conditions.” In Arkansas the Pottsvillian series begins with the Morrow, which, according to D. White, has a flora “of latest or earliest Upper Pottsville age.” In the upper part of the Morrow is the Kessler limestone, beneath which is the shale with the Pottsville flora, followed by the Brentwood or Pentremital limestone. The fauna is largely new, but some of the old species are: Pentremites rusticus, Spiriferina transversa, Hustedia, and Squamularia. “Few paleontologists will at first be willing to accept Pentremites as ranging above the top of the sub-Carboniferous, but the evidence at hand leaves no other conclusion tenable” (Girty, 1905, 9). In the far West occur other pentremite faunas usually regarded as of late “Mississippic” age. ‘These were collected by the Hayden survey and listed by Meek.*** One lot is from “Old Baldy,” near Virginia City, Montana, and among other forms includes Pentremites symmetricus, P. godont ?, Schizophoria resupinata, Composita subtilita, Dielasma bovi- dens ?, Astartella newberryt ?, Trepospira spherulata, etcetera. In the light of the Arkansas collections these fossils must now be referred to the Pottsvillian. At another place on the “Divide between Ross fork and Lincoln valley, Montana,” is found a different fauna, according to Meek 13 Girty : Journal of Geology, vol. 17, 1909, p. 309. 14 Girty : Proceedings of the Washington Academy of Sciences, vol. 7, 1905, p. 8. > Meek: Sixth Annual Report of the U. S. Geological Survey of the Territories for Seo, U8T3. aes 8 ee eee * —— 560 ~=c. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA having, among others, Cyalthophyllum subcespitosum, Lophophyllum, Pentremites bradleyi, P. conoideus, P. godoni ?, P. subconoideus. Pro- ductus longispinus, P. semireticulatus, Humetria verneuliana, Spirifer rockymontanus, Dielasma turgidum, Nucula shumardu, Cypricardima in- dianensis, Conocardium meekianum ?, Huomphalus spergensis, etcetera. “Some seven or eight of the thirty-two or thirty-three species thus found seem to be in all respects, so far as the specimens afford the means of com- parison, identical with forms occurring at the celebrated Spergen Hill locality” ; and the others “belong to genera found at that locality, and so closely resemble [that fauna] in their small size and other characters that they may be regarded as representative forms.” Meek looked upon the horizon “as representing the Saint Louis limestone” (433, 434). The . presence of Productus longispinus and the corals denotes forms unknown in the Spergen fauna, and it is probable that this dwarf biota represents a holdover into Pottsvillian time, being presumably of the same horizon as that at Old Baldy. Moreover, Ulrich has shown that. this dwarf fauna recurs at four different levels in the Tenneseic, and he has recently in- formed the writer that a further recurrence has been discovered in the Pottsvillian of Missouri. The Old Baldy locality he believes to be contem- poraneous with the Arkansas Morrow formation, which he regards as of early Pottsvillian time.*“® Since the above was written, the writer was shown by Raymond collec- tions made by him in the vicinity of Old Baldy, Montana. From the — lower beds he has Petremites large, near P. obesus, and P. fohesi, Produc- tus cf. fasciculatus, Rhynchonella (?) metallica, Composita subquadrata, Cletothyridina roysu, Humetria verneusliana, Dielasma turgidum, etcetera. From higher strata Syringopora multattenuata, Michelinia, Productus cf. fasciculatus, P. nebrascensis, Orthotetes robusta (small), Pugnax rocky- . montana, Spirifer near camerata, and Hall and Whitfield’s S. striatus, Spiriferina spinosa, Hustedia mormoni, Eumetria vera, Composita sub- quadrata, Cleiothyridina orbicularis, etcetera. Near the top of the forma- tion occur Productus costatus, P. semireticulatus, P. punctatus, and Oom- posita subtilita. These faunules, therefore, bear out the conclusion that they represent the time of the Morrow of Arkansas or the earliest Potts- villian. In regard to the Pottsville Girty states: “From its faunal side it is of little interest in the way of correlation in the Central and Eastern States. It will, however, probably establish some interest- ing relations between beds of the West and the Southwest.. The Pennsylvanian 16 Ulrich: Professional Paper no. 24, U. S. Geological Survey, 1904, p. 111. PENNSYLVANIC—PERMIC PERIOD Hal faunas of the West have often a facies which is novel and perplexing to one familiar only with the well known WHastern ones; and it is probable that the lowest faunas of this region will in many cases prove to be of Pottsville age. The resemblances to the fauna of the Morrow formation . . . are ‘sufficiently numerous and striking to make this a very promising hypothesis. “Tt will be remembered that C. D. Walcott described an interesting fauna from the Eureka district, in which there was found a commingling of Upper and Lower Carboniferous types. This is likely to prove of Pottsville age. The lowest Pennsylvanian faunas of Colorado and of New Mexico, especially the latter, also show similarities which appear to me highly significant. The Bend and Milsap formations of Texas may likewise prove to be Pottsville” ‘(Girty, 1905: 10). The following are some of the more characteristic fossils of the Potts- villian (A= Appalachian region, W = Southwestern and Western, no letter == both regions): Triticites secalicus, Lophophyllum sauridens (W), Cystodictya carbonaria (A), Rhipidomella pecosi (W), Chonetes mesolobus, C'. platynota (W), Pugnax rockymontana (W), Productus longispinus, P. muricatus, P. nebrascensis, Spirifer cameratus, S. rocky- montana, Spiriferina kentuckyensis (W), Hustedia mormom (W), Clevothyridina roisi (W), Composita subtilita, Squamularia perplexa (W), Dielasma millepunctata (W), Aviculopecten occidentalis (W), A. _coxanus, A. hertzerr (A), A. whiter (W), A. interlineatus (A), Pinna peracuta, Aviculopinna americana (A), Astartella vera, A. varica (A), Macrodon obsoletus, M. carbonarius, M. tenwistriatus (A), Schizodus subcircularis, S. affinis, Lima retifera, Bellerophon percarinatus (A), Patellostium nodocostatum (W), Euphemus nodocarinatus (A), E. car- bonarwus (A), Stearoceras gibbosum (W). In the Bend of Texas occur Gomiatites striatus, G. crenistria (both occur lower in shales correlated by J. P. Smith with the Batesville or Fayetteville of Arkansas), Gastrioceras entogonum (also in Fayetteville), G. compressum, Paralegoceras iowense (also in “Coal Measures” of Iowa), P. texanum, Metacoceras walcott, and Stearoceras gibbosum.1* Accord- ing to Cummins,’"® there are also included Hadrophyllum aplatus, Cho- netes mesolobus, Productus nebrascensis, Spirifer cameratus, Myalina sub- quadrata, Huphemus carbonarvus, etcetera. Ulrich1*® likewise regards the Bend as of early Pottsvillian time. According to paleobotanical evidence the Pottsvillian, together with the Allegheny, “approximately represents the Westphalian or Muscovian” of Europe. “The Westphalian is the period of Cheilanthites, Mariopteris. Wm Smith: Monograph 42, U. S. Geological Survey, 1903. “8 Cummins: Second Annual Report of the Geological Survey of Texas, 1891, p. 366. 179 Ulrich: Professional Paper no. 24, U. S. Geological Survey, 1904, p. 111. 562 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Diplothema, Crossotheca, Hremopteris, Palanopteris, Lonchopteris, Mega- lopteris, Lesleya, Neriopteris, Bothodendron, Ulodendron, Lepidophoros, and Whittleseya. . . . One-half of these genera scarcely, if at all, survive the Pottsville. Three or four only outlive the Allegheny. The Westphalian witnessed the maximum development in Sphenopteris, Neu- ropteris, and Alethopteris, and of the great Lycopod group. It is pre- eminently the stage of the Cycadofilices.”1®° Missourian or Upper Pennsylvanic. In the northern Appalachian area the Coal Measures or Missourian series embraces the Allegheny, Cone- maugh, and Monongahela stages. As in the Pottsvillian below, these for- mations rarely have normal marine faunas, and when they are present the variety and abundance never equal that of the western area of the Mississippian sea. The lower half of the Conemaugh has at least three distinctly marine horizons—Brush creek, Pine creek, and the Ames or “crinoidal limestone.” In the first or lowest horizon, Raymond?*! has found Margintfera wabashensis, Astartella vera, Patellostuum montfortia- num, Huphemus carbonarius, Bellerophon percarinatus, Trepospira ili- noisensis, Worthenia tabulata, Spherodoma primagema, Bulimorpha niti- dula, and EHuomphalus catilloides. Just below the Ames limestone, in “red structureless clay,” “at least 725 feet below the Permian (Dunkard series),” he has also found bones of Amphibia and Reptilia, recently de- scribed by Case (ibid., 1908). These remains pertain to Hryops, the dia- dectid reptile Desmatodon hollandi, and the pelycosaurid reptile Nao- saurus (?) raymondi. This discovery is of very great interest, as show- ing that the Permic reptilian fauna was in existence as early as middle Upper Pennsylvanic time. The forms represented appear to be more primitive than those of the Wichita, thought to lie at the base of the Permic. In the northern Appalachian area, the Ames limestone marks the last marine invasion during Pennsylvanic time. The higher lime- stones are without marine fossils, and are regarded as of fresh-water origin, owing to the presence in them of from 2 to 5 coal seams. The fossils are said to be common at times,’*? but of few species, usually Ostracoda, Spirorbis anthracosia, and Anthracopupa ohtoensts ?. The Upper Pennsylvanic deposits of the northern Appalachian area are correlated by D. White?*? as follows: “IT would provisionally place the greater part, if not all, of the Conemaugh together with the Monongahela in the Stephanian. . . . The Stephanian or 180 I). White: Journal of Geology, vol. 17, 1909, pp. 327-328. : 181 Raymond: Annual Report of the Carnegie Museum, 1909, p. 169. 182 Hyde: American Journal of Science, vol. 25, 1908. 188 White: Journal of Geology, vol. 17, 1909, p. 329. PENNSYLVANIC—PERMIC PERIOD 563: Ouralian (including the Gschellian) of Hurope dates from the Hercynian uplift. Prior to this movement the sea had reached its maximum extension in the coalfields of the northern hemisphere. . . . The final exclusion of the sea from the Appalachian trough appears to have occurred soon after the depo- sition of the Ames limestone, near the middle of the Conemaugh. .. . It is probable that the Monongahela was never deposited in the southern Appa- lachian region, from portions of which the Conemaugh may also have been absent. “In eastern America, where the relations of land and water were but grad- ually altered and the sedimentation was continuous, the passage to the Stephan- ian flora has no line of sharp paleobotanical demarkation.” For the same reason ‘‘the Stephanian types persist far up into the Dunkard formation. “The Stephanian is marked by the great development of Pecopteris, Callip- teridiwm, and Odontopteris of the true type. It witnessed the nearly complete disappearance of Alethopteris, Sigillaria, and Lepidodendron. . . . Before its close appear the first representatives of Callipteris, Walchia, Teniopteris of the simple type, Pterophyllum, Zamites, and Plagiozamites, all character-. istic of the Permian or later periods.” In the upper Mississippi valley, and especially in Kansas, Nebraska, Towa, Missouri, and Illinois, the deposits of the Missourian are usually of normal marine origin, and here the fossils of this time occur in abun- dance. ‘The term Missourian has been selected for this series in prefer- ence to Coal Measures. As finally defined by Keyes, Missourian embraces all between the Cottonwood at the top of the Kansas section and the Win- terset of Iowa or the Bethany of Missouri, which represents the base. The writer, however, makes use of the term to include all of the Kansas sec- tion from the base of the Cherokee to the top of the Neosho (see table, page 558), preferring thus to extend the meaning of Missourian rather than to coin another new term. Thus far no well defined, or, rather, easily discerned, zones have been pointed out. Girty’® has determined a mass of material, collected at nearly 500 stations in Kansas, and representing 164 species. These are arranged in 46 stratigraphic zones as determined by Adams. 'The lowest horizon is the Cherokee at the base of the Missourian, and probably ex- tending into the late Pottsvilian. The seven highest zones are generally referred to the Permic or “Permo-Carboniferous.” Girty states: “The table shows the evolution of the latest from the earliest faunas in the sec- tion to have been a progression from a brachiopod to a pelecypod facies. It is without marked interruption at any point, so that sub- divisions appropriate for recognition are not clearly apparent.” Chonetes mesolobus is restricted to the six basal zones. The following are the more characteristic fossils of the Missourian, restricting the term in this. 184 Girty : Bull. no. 211, U. S. Geological Survey, 1903. Syes 564 cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA ease to the zones above the Cherokee and below the Wreford, or to zones 2 to 39, inclusive, of the table: Triticites secalicus, Lophophyllum pro- liferum, Campophyllum torquium, Chetetes milleporaceus, Eupachycrt- nus magister, Erisocrinus typus, Ceriocrinus hemisphericus, Phialocrimus magnificus, Rhipidomella pecosi, Enteletes hemiplicata, Orthotetes crassa, Meekella striaticostata (also in Permic), Chonetes flemingt, C. verneuilt- anus, Productus cora, P. nebrascensis, P. pertenuis, Marginifera wabash- ensis (also above), Aulacorhynchus millipunctatus, Spirifer cameratus, Spiriferina kentuckyensis, Composita subtilita (also above), Dielasma bovidens, Hustedia mormoni, Pugnax utah, Aviculopecten occidentalis (also above), A. carboniferus, Myalina subquadrata, M. perattenuata (also above), M. swallovi, M. kansasensis, Lima retifera, Allorisma termi- nale (also above), Limoptera, Pteria, Pleurophorus, Pseudomonotis hawni (most common above; the genus first appears in zone 16), Sole- niscus ponderosus, Trachydomia wheeler, Trepospira spherulata, Worth- enia tabulata, Phanerotrema grayvillensis, Euphemus carbonarwus, and Bellerophon crassus. Elsewhere in the Coal Measures these goniatites are found or the am- monites Agathiceras ciscoense (Cisco only), Dimorphoceras texanum (Cisco only), Gastrioceras globulosum (Cisco), G. illinoisense (Illinois), G. kansasense (Missouri and Kansas), G. montgomeryense (Illinois), G. planorbiforme (Missouri), G. subcavum (Illinois and Texas), Gomolobo- ceras wellert (Illinois and Texas), Popanoceras ganti (Cisco; the genus extends upward), P. parkeri (Strawn of Texas), Schistoceras (four spe- cies restricted to the Coal Measures in Ohio, Illinois, Missouri, and Texas), Schuchertites grahami (Cisco only), and Shumardites simondst (Cisco only). The, plants of the Missourian in Kansas have been studied by D. White,*®* and his conclusions are as follows: “The flora of the Cherokee at the base of the ‘Coal Measures’ falls within the Allegheny formation of the Appalachian basin.” Elsewhere it has “close relationship with the _ Cherokee flora of Henry county, Missouri, [and] the Mazon Creek stage of the Illinois Coal Measures.” About the middle of the Pottawatomie (see table, page 558) is another floral horizon that does not “seem to be of an earlier date than the Freeport, the uppermost division of the Allegheny formation” (ibid., 112). At the base of the Douglass the plants seem “to point toward a level possibly as high as the Pittsburg coal” at the base of the Monongahela (ibid., 114). Those near the top of the Shaw- nee are also Monongahela. Near the top of the Wabaunsee the flora is 18 White: Bull. no. 211, U. S. Geological Survey, 1903, p. 111. PENNSYLVANIC—PERMIC PERIOD 565 “clearly indicative of a stage at least very high in the Upper Carbonifer- ous (Pennsylvanic). Nearly all the species have been reported from either the Permian of Europe or the Dunkard formation of the United States. . . . Yet the small flora from Onaga [Wabaunsee stage] contains none of the special types or characteristic Permian forms which are present in the Dunkard, and on account of which the greater part of the Dunkard is regarded as Permian” (ibid., 115). Judging from the evidence furnished by the invertebrates, this formation is best left in the Pennsylvanic system. In the Rocky Mountain region.the late Pottsvillian faunas everywhere appear to have been followed by an erosion or land interval. How long this emergence persisted can not as yet be estimated, but the Mississippian sea, with its well known Missourian fauna, apparently reentered the Rocky Mountain area long before the close of the Pennsylvanic, and then, under practically the same physical conditions as those of the Mississippi valley, continued well into the “Permo-Carboniferous” or Oklahomian epoch. The Californian sea extended east into the Cordilleran region to the west of a land barrier, and late in the Pennsylvanic almost united with the Mississippian sea. Both marine areas then persisted independently into Oklahomian time, but the Pacific waters in the Sonoran sea continued long after the Mississippian sea had vanished in red beds and gypsum deposits. 'The spread of these waters will now be taken up in greater detail. According to Cross,1** the Hermosa formation of limestones, shales, and sandstones occurs 1n southwestern Colorado, with a maximum thickness of 2,000 feet. The Molasse is at the bottom of the Hermosa. According to Girty, the fauna “is probably older than the ‘Upper Coal Measures’ faunas of the Kansas and Nebraska sections.” Nearly all the forms are those of the Mississippi valley. Some of these are: T’riticites secalicus, Chetetes milleporaceus, Prismopora serrata, Meekella striaticostata, Chonetes meso- lobus, Productus cora, P. punctatus, P. nebrascensis, Marginifera wabash- ensis, Spirifer rockymontanus, S. cameratus, Squamularia perplexa, Spi- riferina campestris, Composita subtilita, Myalina subquadrata, Bellero- phon crassus, Patellostuum montfortianum, Euphemus nodocarinatus, and. Phillipsia major. At Moab, Utah, and in Sinbad valley, on the Colorado-Utah line, Girty'®’ has also determined Syringopora multattenuata, Lophophyllum profundum, Campophyllum torquium, Axophyllum rude, Enteletes hemi- 18 Cross: Folios 120, 130, 181, and 153, U. S. Geological Survey. 18 Girty in Cross: Journal of Geology, 1907, pp. 668-676. 565 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA plicatus, Chonetes granulifer, Hustedia mormom, Dielasma bovidens, Chenomya leavenworthensis, etcetera. To the writer, the Hermosa appears to be best correlated with the Upper Missourian. Guirty, however, correlates the Weber and the Lower Maroon of northwestern Colorado with the Hermosa. The Weber conglomerate and sandstone represent, according to Hague,*** “one of the most persist- ent and well defined horizons over wide areas of the Cordillera, stretching westward all the way from the Front Range in Colorado to the Hureka mountains.” In the Eureka district the “thickness is estimated at about 2,000 feet’? (8,000 in the Oquirrh mountains). No fossils oceur here. In Nevada, above the Weber, follow the “Upper Coal Measures” lime- stones, attaining a depth of nearly 2,000 feet. The fauna is essentially the same as that of the Missourian of the Mississippi valley. In Nevada the series is terminated by limestones nearly 2,000 feet thick, bearing the same fauna, and with a few lignite seams up to 18 inches in thickness. Upon the Hermosa, in southwestern Colorado, is laid down conform- ably the Rico formation of sandstones and conglomerates, with interca- lated shales and thin fossiliferous limestones. The thickness is about 300 feet. Girty'®® reports some of the fossils to be: Productus cora, Com- posita subtilita, Limipecten occidentalis, Myalina wyomingensis, Pseudo- monotis hawni, P. equistriata, P. kansasensis, Pleurophorus subcostatus, Naticopsis monilifera,. etcetera. ‘These species indicate the Permo-Car- boniferous beds of the Kansas section and they show the fauna to be that ~ of the Mississippian sea. Cross and Howe’®® state: “The Hermosa formation appears to occupy the same Stratigraphic position as the Aubrey of Utah and Arizona. Further investigations are necessary, however, to explain certain faunal differences or dissimilarities noted by pale- ontologists between the formations.” | The Aubrey fauna is clearly of the western or Pacific realm. Apparently the Rico equivalent also occurs in the Wahsatch moun- tains, here consisting of argillaceous and calcareous shales, with muddy marls 650 feet in thickness. The fauna includes Pseudomonotis hawni.1** Above the Rico and Hermosa, in southwestern Colorado, are the unfos- siliferous “Red Beds” forming the Cutler deposits. According to Cross,1%” their thickness is not less than 2,000 feet. Above is an erosion interval followed by the Dolores formation of Upper Triassic age. The Cutler 188 Hague: Monograph 20, U. S. Geological Survey, 1892, pp. 91-92. 189 Girty in Cross: Folio 130, U. S. Geological Survey, 1905. 199 Cross and Howe: Bull. Geological Society of America, vol. 16, 1905. 191 King: U. S. Geological Survey of the 40th Parallel, vol. 1, 1878, pp. 164, 173, 245. 192 Cross: Folios 120, 130, 141, and 153, U. S. Geological Survey, 1907. PENNSYLVANIC—PERMIC PERIOD 567 consists of cross-bedded conglomerates, grits, gypsum beds, and red shales, which “are mainly continental deposits.” “As distance from the moun- tain source of these clastic materials increases, the beds are naturally finer grained and grade into shales and marls, and correlation of widely sepa- rated sections becomes difficult.’?°? This horizon is believed to be the continuation of the Oklahomian series of the Kansas section. The Chugwater red beds of Wyoming, averaging 1,200 feet in depth, appear to hold the horizon of the Cutler. The fossils are few and there are no brachiopods. The forms represented are: Schizodus wheeleri, Aviculopecten curticardinalis, Pleurophorus, Bakewellia ?, and Natica lelia.1°* In southwestern Wyoming occurs the Thayer formation, with a thick- ness of 2,400 feet. It probably is the equivalent of the Chugwater and Cutler. The fauna of these beds is composed of pelecypods, some of which are: Aviculopecten weberensis, A. curticardinalis, A. parvulus, Mya- lina permiana, Myacites inconspicuous ?, Bakewellia ?, Schizodus ovatus, Sedgwickia concava. “They indicate an extension into Wyoming of the Permo-Carboniferous of the Wasatch range.”?*° Permic of the northern Appalachian sea.—In this area marine faunas ceased in the upper part of the Conemaugh, and all subsequent deposits are of continental origin. If these are brackish-water deposits, there is as yet no evidence of the fact known to the writer. Above the Monon- gahela rests the Dunkard series of western Pennsylvania, eastern Ohio, and West Virginia. The plants of these beds are Lower Permic, on the authority of D. White, equivalent to the Atunian and Cuseler of Europe. The reference in 1880 of the Dunkard to the Permic, by Fontaine and I. C. White, “has been doubted by most American, geologists. Recently, however, additional plant evidence has been obtained to show that the beds above the Washington coal, 175 feet above the Waynesburg coal [the base of the Dunkard], are clearly Lower Rothliegende (cf. Cuseler) ; and it is not impossible that the Rothliegende boundary may, on the acquisition of further paleontological material, be shown to lie unquestionably below the ‘Waynesburg coal.’’?9° From a parting of the Waynesburg coal near Cassville, West Virginia, at the very base of the Dunkard, Lacoe obtained many insects. Others have been found at Fairplay, Colorado. These have been studied by Handlirsch,*** who has determined 93 forms. All belong to the Blat- 193 Cross: Journal of Geology, 1907, pp. 662-668. 194 Darton: Bull. Geological Society of America, vol. 19, 1908, p. 438. 1% Girty in Veatch: Professional Paper no. 56, U. S. Geological Survey, 1907, p. 52. 196 J). White: Proceedings of the U. S. National Museum, vol. 29, 1906, p. 665. 1% Handlirsch : Fossilen Insekten, 1906-1908, p. 1149. ee . ee ee a 568. Cc. SOHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA toidea and best agree with those of the Cuseler. He states that the Palzodictyoptera so characteristic of the Missourian are absent here. The evidence furnished by the insects is therefore in harmony with that of the plants. Permic of the Mississippian sea—tIn this province the Missourian ma- rine deposits pass without break into the “Permo-Carboniferous,” and stratigraphers have differed as to where in this section the line should be drawn between the Pennsylvanic and the Permic. There is no natural limit here, and the line of separation must always be an arbitrary one. The other debated question is, Shall these higher deposits be referred to the Pennsylvanic or to the Permic system? The answer will depend on whether the Permic shall be restricted to the type area—the Perm region of the Ural mountains of Russia—or whether the view shall be adopted that the Russian formation known as the Artinsk is best referred to the Permic, using this term in the wider sense. The latter view is the one more generally accepted, and also the one adopted here. Following the work of Prosser, the writer will therefore draw the Permic line at the base of the Wreford limestone of Kansas. Not many typical Missourian species pass above this line, and most of these begin in the upper part of the Pennsylvanic. Of the 164 Kansas species listed by Girty,*°® 46 pass into the basal Permic beds known as the Chase and Sumner, and 12 are restricted to them. Of the former, 24 range throughout the Missourian, and some of these even from the Pottsvillian; 14 others begin near the. middle of the Missourian, and 8 take their rise a little below the Wreford. These figures show that there is here a complete transition, but, as will be seen, the faunal changes are largely brought about by the dropping out of the brachiopods and the appearance of new forms, chiefly pelecypods, but in the south of ammonites. For this transition series the writer adopts Keyes’s Oklahomian, as his emended definition embraces all the so-called Permo-Carboniferous. ‘The series, therefore, represents the lower portion of the Permic in the wider sense, and it is all probably older than the true Permic of the Perm district of European Russia. The more characteristic fossils of these transition beds are: Pseudo- monotis hawnt (this form also occurs below, and the genus goes about half way down in the Missourian), Myalina aviculoides (below), M. per- miana, Bakewellia ( ?) parva, (below), Pleurophorus calhount, P. subcunea- tus, Sedgwickia altirostrata, Chenomya leavenworthensis, C. minnehaha, and Phacoceras dumblei (Fort Riley limestone). Other forms not so characteristic are: Orthotetes robusta, Meekella striaticostata, Productus nebrascensis, Marginifera wabashensis, and Composita subtilita. 198 Girty: Bull. no. 211, U. S. Geological Survey, 1903. PENNSYLVANIC—PERMIC PERIOD 569 In the Kansas section, near the top of the Sumner, occurs a flora that Sellards regards as of Lower Permic age. This conclusion is borne out by White’s?®® statement that ‘Sf the composition of the entire flora proves to be of so young a character as the material described or placed in my hands by Mr Sellards, his conclusion that the beds are of so late date as the Lower Permian will appear to be fully justified. . . . Probably of a date fully as late as the earlier of the floras generally referred to the Permian in western Europe.” The Sumner formation also yields an abundant insect fauna very dif- ferent from that of the Pennsylvanic. But few of these are as yet de- scribed by Sellards.?°° “Over two thousand specimens are now at hand [and give] the most complete record of Permian insect hfe thus far ob- tained.” Ephemerids are unknown beneath the Permic, and Sellards here described 12 new species. In Texas occur far more characteristic Oklahomian fossils associated with many Pennsylvanic survivors. In the Albany series are the ammo- nites Phacoceras dumblei (also in the Fort Riley limestone of Kansas), Medlicottia copei, Popanoceras walcottt, Paralegoceras taylorense, Waagen- oceras cumminst, and Coloceras globulare. Of nautiloids occur Domato- ceras simplex, D. militarium, Tainoceras occidentalis (also below), Tem- nocheitlus winslowr (below), and T. conchiferus. In the Double Moun- tain series (which may be but another petrologic phase of the Albany and Wichita), Waagenoceras hilli is found. These forms are thought to hold the time of the European Artinsk, referred by stratigraphers to the Permo- Carboniferous or the Lower Permic. Concerning the divisions of the Wichita, Clear Fork, and Double Moun- tain, Adams?" states: | “It may be said that there is little reason to believe that they should be any longer retained, since they have no stratigraphic significance. It appears that what have been called the Clear fork and Wichita divisions by Mr Cummins are the equivalents, in part at least, of the Albany.” The Wichita-Brazos region has been restudied by Gordon,?°? and his con- clusions are as follows: The Wichita and Clear Fork, usually regarded as of Permic age, “when traced along their strike toward the southwest. are found to grade into those included under the terms Cisco and Albany. . . . An abundant marine fauna characterizes the beds toward the south. In the Red Bed region marine 199 White: Bull. no. 211, U. S. Geological Survey, 1903, p. 117. 200 Sellards: American Journal of Science, September, 1906, and May, 1907. 2021 Adams: Bull. of the Geological Society of America, vol. 14, 1903. 202 Gordon: Science, May 7, 1909, p. 752. XLIX—BULL. GEOL. Soc. AM., Vou. 20, 1908 : ————— eee eee eee Se ee 570 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA forms are few, appearing only in the few beds of limestone that persist. Along with them in this region appear vertebrate remains upon which the references to the Permian have been based. It is the conclusion of the author that the Red Beds of this region are the near-shore representatives of the Albany and the decision as to their age will rest upon that of the latter.” Yn this connection it should be stated that Cummins?®* has recently given “the localities and horizons of Permian vertebrate fossils in Texas.” He shows that the two divisions Wichita (includes the Albany) and Clear Fork have distinct vertebrate associations (the Double Mountain division is almost devoid of these remains). The Wichita i8 marked by the stego- cephalian genus Cricotus, by the reptilian Cotylosauria genera Chilonyxr and Bolosaurus, and the reptilian Pelycosauria genera Clepsydrops, Cteno- saurus, Theropleura, Metamosaurus, Paleosaurus, and Embolophorus. Restricted to the Clear Fork there are of Stegocephalia Diplocaulus, Dissorhopus, Acheloma, and Antsodexis; of Cotylosauria Bolbodon, Iso- dectes, Hypopnous, and Labidosaurus ; all the Chelydosauria ; and of Pely- cosauria Hdaphosaurus. — Common to the Wichita and Clear Fork there are of Stegocephalia Trimerorhacis, Zatrachys, and Eryops; of Pelycosauria Diadectes, Hmpe- dias, Pariotichus, and Pantylus; of Pelycosauria Dimetrodon and Naosau- rus. With this evidence at hand, it must be agreed, at least for the pres- ent, “that the divisions of Wichita and Clear Fork which were proposed at first on purely stratigraphic grounds are fully warranted and upheld by the fossils found in them” (Cummins). In the Whitehorse member of the Woodward Pasa Beede?°* describes among others from Oklahoma Dielasma schucherti (certainly a Permic type of brachiopod) and a number of pelecypods. From the Quartermaster division come the same brachiopod, many new pelecypods, and univalves. In the Red Beds of the Enid of Oklahoma there has been found the phyllopod Estheria minuta, the amphibians Hryops megacephalus, Diplo- caulus, Trimerorhachis, Cricotus, Cricotillus (restricted here) ,and Crosso- telus; and the reptiles Naosaurus, Pariotichus, and Plewristion. These belong to the same general land fauna as that found in the Wichita of Texas. The latter area contains a far greater number of amphibians and . reptiles, which have been described by Cope. Recently Case*°’ has restud- ied the Pelycosauria. | The plants collected by Cummins in the Wichita are, according to Fon- taine and I. C. White,?°° identical with those of the Dunkard Creek series 208 Cummins: Journal of Geology, vol. 16, 1908. 204 Beede: Kansas University of Science, Bull. no. 4, 1907. 205 Case: Publication no. 55, Carnegie Institution of Washington, 1907. 206 White: Bull. Geological Society of America, vol. 3, 1892, p.°217. Pie "* PENNSYLVANIC—PERMIC PERIOD alk of West Virginia. This series begins with the Waynesburg coal, and White has always regarded it as recording the time of the Permic. Case?°’ has recently reviewed the vertebrate evidence on which Ameri- -eans have placed such dependence as proving the Permic age of the Wich- _ ita red beds of Texas. Since Raymond found reptiles in the middle Cone- maugh, which is even below the Monongahela, the uppermost series of the Pennsylvanic, reliance can no longer be placed on the mere presence of reptiles as positive proof for Permic age. This discovery led to Case’s review, and he concludes as follows: “The evidence from vertebrates is not sufficient to demonstrate the Permian age of the beds in Illinois and ‘Texas ; they may reach down into the Carboniferous.” It is now fairly well established that the Wichita and its fauna and flora are not of true Permic time, but belong to the older Permic, the so-called Permo-Carboniferous or Oklahomian, or the European Artinsk. The Wichita flora correlates with the Dunkard, and the latter with the European continental deposits, the Atunian and Cuseler, or the Rothlie- gende. It is even possible that the Wichita is slightly older than the latter, but in any event the ammonites correlate best with the Artinsk. Throughout the Mississippian sea the Oklahomian deposits are those of a vanishing sea with abnormal marine conditions. Vast areas consist of nothing but red beds, with here and there thin dolomite layers, and in many places gypsum occurs In quantity, especially in Oklahoma, the ~ “Gypsum State.” In Kansas the earliest Oklahomian deposits are still those of normal marine waters, and this condition probably continues longest in the Albany of Texas. Californian sea.—In California the equivalent of the Pennsylvanic has at its base the Bragdon “shales, sandstones, and tuffs, with siliceous con- glomerates (of Devonian pebbles) increasing in number and size from the top toward the bottom.’’?°§ The thickness is estimated at 2,900 feet, and may attain to 6,000 feet. The fossils of this formation are very few, but these link it directly with the overlying Baird. Among other forms were found a Glyphioceras similar to sphericus and Lithostrotion subleve. Diller refers this formation to the Mississippian. It may be that this zone is older than the Pottsvillian, in which case it is of late Tennesseic time. All depends on the age of the following Baird, which Diller? also refers to the Mississippian, but which the writer regards as very early Pennsylvanic—that is, Lower Pottsvillian. | The Baird “reddish shales and sandstones with much volcanic mate- 2077 Case: Journal of Geology, 1908, p. 580. 208 Diller: American Journal of Science, vol. 19, 1905, p. 383. 20 Diller: Folio 138, U. S. Geological Survey, 1906. See ae SSS SESE SK 972 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA rial” are estimated by Diller to have 1,000 feet of thickness. Near the United States Fishery Station, on the McCloud river, is found an abun- dance of fossils, a good collection of which is now in the U. S. National Museum. ‘They occur in the upper 150 feet of the Baird, and were pro- visionally identified about fifteen years ago by the writer. The fauna may be known as the Productus giganteus. Some of the more characteristic forms are: Productus giganteus (not typical with the European species of Martin), P. punctatus, P. semireticulatus, Cleiothyridina roysi ?, large Camarophoria, Rhipidomella corallina (Waagen), Bellerophon cf. ste- vensanus, Pleurotomaria ef. newportensis, and carbonaria, P. cf. subsin- uata, Bulimorpha nitidula, Aviculopecten interlineatus, Streblopteria, Inma retifera, Edmondia cf. aspinwallensis, Pleurophorus (3 species), and Allorisma. , From the foregoing list it may be seen that the fauna has a decided Pennsylvanic aspect and that some of the species are also found in the Mississippi valley. Associated with these are forms clearly of Asiatic origin, which become more common in the higher beds. As there is prac- tically nothing in this fauna resembling that of the Tennesseic, it is here regarded as of early Pennsylvanic time, and is probably the equivalent of the Lower Pottsville of the Appalachian and Mississippian seas. Smith??? refers the horizon to the Lower Carboniferous, and identifies in it (in all probability erroneously) Mississippic, Tennesseic, and Pennsylvanic forms. The Russian geologists refer their Productus giganteus zone to the Lower Carboniferous, which they correlate with the Belgian Viséian. Daly has collected and Ami has identified Productus giganteus in the Flathead river region of southwestern British Columbia. In southeastern Alaska, on Chichagof island, at Freshwater bay, Kindle has found the same species. From these occurrences it is seen that this fauna is wide- spread along the Pacific coast, but thus far it is not reported from the Arctic regions, although Spirifer mosquensis of the next higher zone is said to occur there. According to G. M. Dawson,?™ this and the later Pennsylvanic sediments are widely distributed in British Columbia, and are “mingled with contemporaneous volcanic materials, . . . tran- quil epochs being marked by the intercalation of occasional limestone beds.” Above the Baird shales follows the McCloud limestone, said by Diller to vary between 200 and 2,000 feet in thickness. At the base is found the Omphalotrochus whitneyi fauna in part described by Meek in the Califor- nia Report. Besides this large gastropod, there is an abundance of the 210 Smith: Journal of Geology, 1894, pp. 594-599. 211 Dawson: Bull. Geological Society of America, vol. 12, 1901, p. 85. PENNSYLVANIC—PERMIC PERIOD Dio foraminifer Schwagerina and the corals Clisiophyllum gabbi, Lonsdalia sublevis, L. californmense, Syringopora multattenuata ?, Hustedia com- pressa, etcetera. Girty??? correlates this formation with “the lower por- tion of the Hueco.” The latter “will perhaps prove to be the same as the Aubrey formation of northern Arizona,” both of which are regarded as of late Pennsylvanic age. This horizon also appears in Alaska and the Arc- tic regions, being here marked by Spiriferella arctica. When these strange faunas were first seen by the writer,?"? particularly because of the variety of the Producti, he regarded their age as Permic. It is now known that they correlate best with the Omphalotrochus and higher Pennsylvanic faunas of California and Russia. The writer was first impressed with | this resemblance while on a visit to the Geological Survey collection at Saint Petersburg, in 1903, and he still regards the Alaskan faunas as best compared with the Omphalotrochus and Productus cora zones of Russia. - The McCloud limestone is succeeded by the McCloud shale, or Nosoni formation, “composed very largely of andesite or basalt tuffs and tuffa- ceous conglomerates and a few flows of lava, but locally interstratified with these volcanic products are shales and sandstones, in part calcareous, and often rich in fossils.” The thickness varies between 500 and 1,200 feet. On Little Grizzly creek, Plumas county, occur Fusulina elongata, Chonetes (a large new form), Marginifera longispina, Rhipodomella pe- cost, Pugnax utah ?, Uncinulus cf. theobaldi, Meekella cf. striaticostata, Spirifer much like camerata and musakheylensis. Girty states that the “McCloud shale may provisionally be correlated with the upper Hueco- nian.” It also seems to correlate with the Schwagerina zone of the Russian geologists. This zone is just below the Permo-Carboniferous or Artinskian. - Huecoman (Pennsylvanic) of the Trans-Pecos region of Texas.—In this part of Texas there is no equivalent of the Pottsvillian, the Hueconian apparently representing the Upper Missourian of the Cordilleran region. The Hueco formation consists of a massive limestone with zones of shale and sandstones, ranging in thickness from 3,000 to 5,000 feet. The fauna found at the base is somewhat similar to that of the late Pottsvillian, but the higher assemblages are quite different from those of the Pennsylvanic of the Mississippi valley and are mostly undescribed. “Through the West, however, these faunas will probably prove to have extended widely.” The Hueco “will perhaps prove to be the same as the Aubrey formation of northern Arizona” (Girty, 1905, 14). 212 Girty : Proceedings of the Washington Academy of Sciences, vol. 7, 1905, p. 16. 213 Schuchert in Mendenhall: Professional Paper no. 41, U. S. Geological Survey, 1905, pp. 42-45; also Kindle, Journal of Geology, 1907. pF oes & ht BE 2 ee & Pesy 574 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Near the base of the Hueco, Girty records Triticites, Productus cora, Marginifera cf. wabashensis, Squamularia perplexa, Spirifer rockymon- tanus. It will be seen that these forms are suggestive of those of the higher Pottsvillian. In higher beds at different horizons, Girty?** col- lected among other forms Fusulina elongata, Schwagerina ?, Lithostro- tion, Chetetes milliporaceus, Orthothetina, Enteletes, Camarophoria, re- lated to European forms; Pugnazx, Productus, related to Ural and Aubrey forms; Spirifer cf. marcout, Hustedia, Composita mexicana, Omphalo- trochus obtusispira, etcetera. - The Aubrey extends to within 25 miles of Moab, Utah, yet its fauna is very different from that of the Hermosa of the Mississippian sea. The writer believes that the Aubrey faunas are younger than those of the Her- mosa, but still Pennsylvanic, and of a distinct faunal province—that is, of the western or Cordilleran basin. The Aubrey limestone on Kanab creek attains a depth of 820 feet, while the underlying Aubrey sandstones, with gypsum, along the Grand Canyon reach about 1,000 feet.?1° In the Grand Canyon region the Aubrey is followed by the Shinumo sandstone, 250 feet in thickness. It appears to be a dune sandstone for- mation. Above this is the Sublime limestone and calcareous sandstone about 600 feet in thickness, near the middle of which, in a zone 200 feet thick, oceurs the fauna described by Newberry. This is the Productus: west fauna, and includes Archeocidaris longispina, Meekella occidentalis, M. pyramidalis, Productus wesi (the guide fossil), P. nodosus, P. occi- dentalis, Aviculopecten coloradoensis, and Allorisma capac. There are many other species, not one of which is familiar when compared with the eastern Missourian forms. In Utah are found Chonetes utahensis, Pro- ductus semistriatus, P. multistriatus, Spirifer scobina, S. cameratus occi- dentalis, and Spiriferina pulchra. The Embar formation of central Wyo- ming also displays the 8. pulchra fauna. The Embar limestone, Girty?** says, “has a very different fauna from the Kansas Permian, but it may be equivalent to it, or even later. The fauna is not related to the Guadalu- pian. It occurs in Utah just below the Permo-Carboniferous, and is known also in Idaho and Nevada.” In a very recent paper Girty?”’ states: “The Mississippian faunas, together with the earlier Pennsylvanian ones, appear to be absent [in the Trans-Pecos region]. The Hueconian fauna is widely distributed over the West, ranging indeed into Alaska, while it is even 214 Girty in Richardson: Bull. no. 9, University of Texas Mining Survey, 1904. 215 Spurr: Bull. no. 208, U. S. Geological Survey, 1903. 216 Girty in Darton: Bull. Geological Society of America, vol. 19, 1908, p. 418. 217 Girty : Journal of Geology, 1909, p. 311. er ( PENNSYLVANIC—PERMIC PERIOD a) recognizable in Asia and eastern Europe. Most of the occurrences of Carbon- iferous in the West can be referred to this series, although some of them pre- sent more or less distinctive facies.” Guadalupian (Permic) of the Trans-Pecos region of Texas.—The Hue- conian of this area is followed by the Guadalupian, but it is not known whether the succession is a continuous one or is broken. At the base are black non-magnesian, bituminous limestones, of which about 200 feet are visible. These are succeeded by the Delaware Mountain formation proper. consisting chiefly of sandstones in the north and of more calcareous mate- rial in the south, and having a thickness of from 1,200 to 1,500 feet. At the top are dark limestones not less than 100 feet thick, followed by the Capitan white massive limestone about 1,800 feet in depth. Richardson?'* refers the three lower members to the Delaware Mountain formation, while the fourth is the Capitan limestone. These formations have yielded a fauna comprising 326 forms (220 are specifically named), described by Girty2*® in great detail. They are chiefly Protozoa (9 species), Sponges (24), Bryozoa (44), Brachiopoda (128; Productus 25), Pelecypoda (45), and Gastropoda (42). The fauna, while large, is a very strange one, being composed almost entirely of local forms, most of which are small in size. The life of the Guadalupian “is quite unlike the faunas of eastern North America, and almost equally unlike most of those of the West.” “The nearest are probably those of the Salt Range and Himalaya, in India, and of the Fusulina limestone of Palermo, in Sicily.” It “is younger than the Kansas ‘Permian,’ and belongs to a different epoch.” The Delaware and Capitan have a very similar fauna, and are bound together by the following characteristic forms: Fusulina elongata (attains a length of more than one inch), a Mesozoic type of bryozoan near Domo- pora, the brachiopods Streptorhynchus, Orthotetes, Leptodus americanus, many species of sinused, coarsely spinose Producti, Aulosteges, Richtho- fenia permiana, Nothothyris, Heterelasma, many Spiriferina, the pelecy- pods Pteria, and a Mesozoic genus near Camptonectes. In the basal black limestone of the Delaware formation the fauna in some respects retains a Hueconian facies, but that it is of Permic time is shown by the presence of Richthofenia permiana, Aulosteges (2 species), Paraceltites elegans, Peritrochia erebus, and Agathoceras teranum. The survivors are Hnteletes, Meekella, Pugnax osagensis (a Missourian form of the Mississippi valley), Clinopistha ?, Leda, Yoldia, and Naticopsis. 218 Richardson : Bull. no. 9, University of Texas Mining Survey, 1904, p. 38. 219 Girty : Professional Paper no. 58, U. S. Geological Survey, 1908, pp. 28, 39. \y ea Ra SS Se —— 576 C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA The higher Delaware formation introduces among other forms Fusilt- nella, Leptodus americanus (goes above), Richthofenia permiana (goes above), Hnteletes dumblet, E. angulatus, Strophalosia hystricula, Aulo- steges magnicostatus, Meekella skenoides, M. difficilis, Orthotetes nasuta (large, of robusta type) ,Camarophoria venusta, Hustedia bipartita, Bake- wellia ?, Pteria (3), Myoconcha, Pleurophorus, Warthia americana, Waa- genoceras cumminsi guadalupense, and the trilobite Anisopyge perannu- lata (goes above). Besides those mentioned above, the Capitan has the following distinctive forms: Geyerella americana, Leptodus guadalupensis, Strophalosia cor- nelliana (also in Brazil), Pugnax swallowiana, Dielasma prolongatum, Dielasmina guadalupensis, Heterelasma (2), Spirifer mexicanus, 8S. sul- cifer, Spiriferina (7%), Composita emarginata, Hustedia meekana (also below), Camptonectes ? (3), and Patella capitanensis. MESOZOIC HRA Triassic Period See plates 86 and 87 The widely emergent condition of the Permic persists into the Triassic, and in all eastern North America not a trace of marine deposits again appears until well into the Cretacic. Along the border region from South Carolina to Nova Scotia, east of the Appalachians, in isolated structural valleys, continental sediments accumulated, usually red in color, but at the south with coal beds ranging in thickness up to 26 feet. These strata are also known as the Newark series, and are sometimes regarded as ex- tending into the Jurassic, but the plants all seem to be of Triassic time. ‘In the northern areas there are many associated trap flows, both intrusive and extrusive. Marine Triassic of the Pacific realm.—The emergent condition of east- ‘ern North America throughout the Triassic is recorded all the way to the Pacific by the absence of marine formations. The marine record is un- usually complete in a restricted sea covering parts of California, Nevada, Oregon, and Idaho, in sediments with considerable ealeareous material ageregating nearly 4,000 feet in depth. This series is rich in ammo- nites.22° The faunas are Pacific and Asiatic, with decided connections with the great mediterranean Tethys. The lowest Triassic or Meekoceras fauna of California and Idaho Smith?*? states to be a typical Pacific element, common also to the Hima- 220 J. P. Smith: Professional Paper no. 40, U. S. Geological Survey, 1905. 221 Smith: Festschrift v. Koenen, 1907. TRIASSIC PERIOD 517 layas, southern Siberia, and northern Tibet. He also reports that a little later the Tirolites fauna appears, having a decided Mediterranean aspect, but enduring for a short time, and that the Lower Triassic closes with the Columbites biota of few species, having boreal or northern Siberian charac- teristics. Table of Western Triassic Formations. After Smith, 1907 California Nevada Idaho British Columbia Pseudomonotis subcircularis Pseudomonotis Pseudomonotis slates slates slates Spiriferina beds (cd) © S : ar Ss Juvavites beds Zt. Nn : Acs eS eu ee | # = Tropites subbulatus beds Sram Ponieli Bawsones ovo = ° ° 8 2. S No characteristic 2. = fossils = 2 | Halobia superba beds | 3S a Slates with MHalobia ef. TUgOsSa EY Daonella a beds a Slates and tuffs without ean | oO determinable fossils Boa Gymnites = ewig Lees = ak = ) Daonella du- 2 5 Clay and siliceous slates | 2 € &| bia, Ceratites 2 Ea with Anolcites cf. whit- |O =| trinodosus = “age Elles} & a meyi and Ceratites cf. |A beds = humboldtensis al Columbites as ; beds ss) Black limestones with Pa- = rapopanoceras, Xenodis- 80 cus, Arochordiceras, and mairolaked a Hungarites heds 3 1 Ss és = | Caleareous slates without 2. = aa fossils a D = & = a a Meekoceras = = | Meekoceras beds of Inyo beds: 5 S county, Meekoceras gra- = @ cilitatis, Ussuria, Pseudo- g 2 geceras, Inyoites, Owen- = ° . ites, Nannites Triassic elevation still continued in the Rocky Mountain area, and all along the Pacific region there is constant proof of much volcanic activity, for according to Dawson??? the Nicola and Vancouver series in British Columbia consists largely of volcanics and attains a thickness of 13,500 feet. ‘Toward the close of the Lower Triassic the sea was withdrawn from 222 Dawson: Annual Report of the Geological Survey of Canada, vol. 7, 1896. Bull. of the Geological Society of America, vol. 12, 1901, pp. 57-92. LL Le SS A aS es SRR SUE to SS 5 ee aa Be oe 578 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Idaho, but during the Middle Triassic the marine area of California and Nevada was extended into Oregon. The inundation thus started became general in the Upper Triassic all along the Pacific into Arctic Alaska, while in Mexico, for the first time since the Proterozoic, the Gulf of Mexico: spread locally to Zacatecas. The Middle Triassic faunas of the west coast take on more of the Mediterranean type, and are directly correlated with the Ceratites trinodosus zone of Muschelkalk time. The Tethys con- nection is now so marked that, according to Smith,??* “a paleontologist from Austria might be set down in the Humboldt desert, and he could hardly tell from the character of the fauna whether he was collecting in Bosnia or Nevada.” The widely distributed Upper Triassic begins in California with Halo- bia beds, followed by an abundant fauna referred to as the Tropites sub- bulatus zone of decided Mediterranean aspect, since many identical spe- cies occur in the two regions, which are more than 6,000 miles apart. With the same fauna appear various species of ichthyosauroids. The last of the Upper Triassic or Norian time returns to northern Asiatic or boreal conditions and widespread faunas, from Siberia to Japan and from Alaska to Peru. The Upper Triassic from Alaska to Vancouver has a limited fauna marked by Pseudomonotis subcircularis. Newark series of continental deposits——In the Connecticut valley there: are from 10,000 to 13,000 feet of red granitic sandstones and shales, with horizons of black fossiliferous shales and traps. ‘The upper series of sand- stones, conglomerates, and shales, about 3,500 feet in thickness, have diverse types of dinosaur tracks, but very rarely is a skeleton found. The carnivorous forms are represented by Anchisaurus colurus, A. (?) solus, and Thecodontosaurus polyzelus, while the Predentata are present in Am- mosaurus major. Skeletons of a crocodile-belodont reptile, Stegomus longipes, are also found. The middle series of sandstones, shales, and black shales, with three extrusive trap sheets, have a thickness ranging from 2,200 to 3,100 feet, of which the traps show a united depth of be- tween 700 and 900 feet. In the black shales between the traps, represent- ing temporary local bodies of fresh water, are found ganoid fishes of the genera Redfieldius, Semionotus, Diplurus, and Ptycholepis. Of plants, but 11 species are known (far more occur in the Richmond area) of Ofo- zamites latior, Pagiophyllum simile, P. brevifolium, Clathopterts platy- phylla, Loperia carolinensis, Cycadinocarpus chapini, Equisetum, Baeria munsteriana, and Ctenophyllum braunianum angustum. There are also tracks of large dinosaurs. _ The lower series of coarse granitic sandstones, with frequent conglomer- 223 Smith: Festschrift v. Koenen, 1907, p. 408. TRIASSIC PERIOD 5TD ates and some shalés, attain a thickness between 5,000 and 6,500 feet. Very rarely the track of a dinosaur occurs here also, and a single specimen: of Stegomus arcuatus has been found. Also see pages 437 and 438. In the southern or Richmond, Deep river, and Dan river area, Rus- sell?2*states that there is much fine grained, black, highly bituminous slate, with decidedly local bituminous coals, and rarely a zone of black-band iron. ore. The coal beds vary in thickness from a few feet to between 13 and 26: feet in occasional cases. In this area Emmons found the only so-called. mammal jaws, Dromotherium sylvestre and Microconodon tenuirostris. Of reptiles are present Belodon carolinensis, B. leati, and the amphibians. Pariostegus myops and Dictyocephalus elegans. Of plants, about 72 spe-- cles are recorded, among which is the broad-leafed giant fern Macroteni- opteris magnifolia. There are 8 species of conifers, 23 of cycads, 6 of Equisetum, and 35 ferns. Continental deposits of the Rocky mountains.—The marine Triassic of California, Oregon, and Nevada early in this period extended into Idaho, and as continental deposits continued thence into eastern Wyoming. Dur-. ing the Lower Triassic the Pacific marine waters attained to southeastern Idaho, but apparently there is in this region also much material of a continental nature. Farther to the east all of the Triassic appears to be devoid of marine strata, and, according to Williston,??° “in both Kan-. sas and the Lander region of Wyoming, at least a thousand feet of contin-. uous, conformable, uninterrupted, and homogeneous deposits of red sand- stone, deposits utterly barren of all animal or plant remains,” lie above: the Permic and beneath the Upper Triassic, yielding Keuper types of rep-. tiles. These red beds appear to be older than the far more widely dis- tributed Upper Triassic, and all have accumulated under a semi-arid cli- mate, and during a period of widespread crustal movements. The sea was gradually pushed westward, and in the Cordilleran region the area of con- tinental deposits was greatly enlarged, with probable marine connections. in British Columbia and southern California. In many places in the Upper Triassic deposits occur scattered reptilian remains, making thin zones of bone conglomerates.?2® Here and there are also found fresh-water shells of Unio; likewise wood. In the Petri- fied Forest Park of Arizona occur prostrate tree trunks in abundance, some reaching a length of 120 feet, with a diameter of from 6 to 8 feet. Triassic continental deposits are also known in Sonora and Oaxaca, Mexico. In the latter state Wieland informs the writer that the series is: “4 Russell: Bull. no. 85, U. S. Geological Survey, 1892. #9 Williston : Journal of Geology, vol. 17, 1909, p. 396. *°6 Cross: Ibidem, 16, 1908. 580 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA very thick and seemingly passes unbroken into marine deposits of Jurassic age. Plants are said to be abundant. Jurassic Period See plates 88 to 90 Pacific region.—The unstable crustal condition along the Rocky Moun- tain axis during the Triassic was changed in early Jurassic times into epei- rogenic elevation, thus removing the late Triassic submergence from all areas excepting that of the Cook Inlet and Selikoff region of Alaska, and the states of California, Oregon, and Nevada. With these movements there again appear in California marked faunal changes, for the boreal migrations of late Triassic times have ceased, and faunas with Arietites are now present, which Smith thinks may be South American invaders of Mediterranean derivation. The Alaskan Lias submergence is continued into the Middle Jurassic of the Enochkin formation and has a thickness of 1,600 feet. According to. Stanton and Martin,??” the lower third of this series is marked by the bivalves Inoceramus ambiguus, I. porrectus, I. eximius, and I. lucifer, besides the ammonites Stephanoceras loganwm, S. carlottense, Sphero- ceras oblatum, and S. cepoides. Most of these shells also occur on the Queen Charlotte islands. The upper two-thirds of the Enochkin are marked by Cadoceras doroschini, C. schmidti, and C. worsessensku. Along the Pacific border the Middle Jurassic is continued into the Upper Jurassic. In the Cook Inlet country of Alaska the Enochkin per- sists without break into the Naknek, having a thickness of 5,000 feet or more (including some andesite). The guide fossil of this region is a boreal mollusk, either identical with or close to Aucella pallasi. With it are associated the boreal ammonites Cardioceras alternans and C. cordatus. At or near the close of the Middle Jurassic, or, according to Stanton and Martin, during the early part of the Naknek, in the northern Great Plains area, there appeared an inundation of wide extent—the Logan sea—bringing in for a short time a North Pacific or boreal fauna distin- guished by the ammonites Cardioceras cordiforme and Cadoceras, and the cephalopod Belemnites densus. The fauna is not a large one and con- sists mostly of bivalves, as Pseudomonotis curta, Astarte packardi, Pleu- romya subcompressa, Tancredia bulbosa, T. magna, Goniomya montanen- sis, Lima lata, Camptonectes bellistriatus, Gryphea calceola nebrascensis, and Ostrea strigilecula; also the ichthysaur Baptanodon discus. In the Great Plains region the formation has a thickness varying between 100 227 Stanton and Martin: Bull. of the Geological Society of America, vol. 16, 1905. JURASSIC PERIOD 581k and 600 feet. In Wyoming it is known as the Sundance formation, and is correlated by Stanton??* with the Oxfordian, “‘and perhaps the Callo- vian, in whole or in part.” The latter, according to De Lapparent, is the base of the Upper Jurassic. The distribution of this fauna and sea was first mapped by Logan.??° The Great Plains submergence was of short duration, and vanished early in the Upper Jurassic before the Aucella fauna appeared in Alaska in the higher Naknek. This Upper Jurassic Aucella fauna is clearly of boreal origin and spreads south to California, “where it characterizes the Mariposa slate and equivalent formations, continuing through a great thickness of strata to the top of the Jurassic, and passing without any striking change into the Lower Cretaceous.” The earlier Upper Jurassic of California “had a different, though imperfectly known, fauna more closely related to middle European faunas.”?*° During the later Upper Jurassic times elevation again set in with local volcanic activity, and the Pacific extensions were reduced to marginal seas. This movement was the introduction to the birth of the Sierra Nevadas. Mexico—Shortly after the retreat of the boreal or Logan sea all of eastern Mexico began to subside,—a region that, with the exception of the short and local Upper Triassic invasion, had apparently been land since the Proterozoic. This Mexican subsidence is correlated by Burckhardt?*+ with the Kimmeridgian and Portlandian of the late Upper Jurassic. The faunas are unlike those of California and have decided southern European connections, since of the 85 species of ammonites described by Burck- hardt?*? no less than 10 are identical with those of Central Europe (7), boreal Russia (1), and India (2). Boreal species present here are an abundance of Aucella pallasi mexicana and Perisphinctes nikitim. In addition, there are 11 other forms more or less closely related to forms of central Europe, showing that the Gulf of Mexico was in direct communi- cation with the western end of the Mediterranean. Burckhardt states that in both areas “above the Lower Kimmeridgian there are deposits with a great development of Haploceras filiar and Oppelia of the group O. flez- uosa. In the two regions the remarkable genus Waagemnia also appears in _the higher beds, and these in turn are overlaid, in Mexico as well as in France, by the zone with Oppelia lithographica and by the Lower Port- 228 Stanton: Journal of Geology, 1909, p. 411. 229 Logan : Journal of Geology, 1900, p. 245. 230 Stanton : Journal of Geology, vol. 17, 1909, p. 412. 231 Tbidem, 1909, p. 412. 22 Burckhardt: Bol. 28, Instituto Geologico de Mexico, 1906. ———sa. — os ~S ‘ae > = = 582 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA landian.” It is probable that there was also slight and temporary com- munication with the Pacific ocean. | Similar but very late Upper Jurassic faunas occur at Malone, Texas, and are described by Cragin.?*? Continental deposits of the Great plains—The Morrison formation, having a thickness of from 200 to 400 feet, has been placed on the tate Upper Jurassic map (also on Early Comanchic map), yet the faunal evi- dence is equally as good, and even better, for regarding this, the Bronto- saurus horizon, as Lower Comanchic. ‘There are here no direct marine checks to fix the exact age of these deposits. ‘They are, however, younger than Middle Jurassic and older than Washita, or the upper third of the Comanchic. According to Osborn, the mammals compare readily with those from the English Purbeck at the very top of the Jurassic, while the dinosaurs have long been regarded as Wealden in age, which Geikie and most European geologists refer to the Neocomian, equivalent to the lower part of the Comanchic. From this formation there have been described several species of Unio, Vivipara, Planorbis, Lioplacodes, Limnea, Vorticifex, and Valvata. Ac- cording to C. A. White,?** these fresh-water shells “‘ of themselves offer no suggestion of greater age than the Tertiary.” The more characteristic dinosaurs are: Atlantosaurus, Apatosaurus, Brontosaurus, Dviplodocus, Morosaurus, Stegosaurus, Camptosaurus, and Ceratosaurus. Of the small Prototheria mammals may be mentioned: Allodon, Ctenacodon, Styla- — codon, and Diplocynodon. Small cycad trunks also occur in the Upper Morrison (see further remarks on page 586). Maryland.—In eastern North America the lower basal part of the Po- tomac series—that is, the Patuxent-Arundel—is often referred to the Upper Jurassic. Berry has restudied the floral evidence and regards these continental deposits as of Comanchic time. On the other hand, Lull, from the evidence of the dinosaurs, finds the facts in harmony with the age of the Morrison and Wealden. While as yet the proper systemic reference of the Morrison and the Patuxent-Arundel 1s still unsettled, the tendency is to refer both to the Lower Comanchic (also see page 586). Arctic Alaska.—A very thick series of continental deposits of. Upper Jurassic age was discovered by Collier?** in the Cape Lisburne region of Alaska. The series has a thickness of about 15,000 feet, in which there are 39 low grade non-coking coal beds, varying in depth from a few inches 233 Cragin: Bull. no. 266, U. S. Geological Survey, 1905. : 284 White: Bull. no. 29, U. S. Geological Survey, 1886; see also Stanton, Journal of Geology, vol. 18, 1905, pp. 657-669. 235 Collier: Bull. no. 278, U. S. Geological Survey, 1906. COMANCHIC PERIOD 583 to 30 feet. The total thickness of all the coal seen is 137 feet. The plants indicate Upper Jurassic age, but not so young as Wealden. On Prince Patricks land (latitude 76° 20’ north, longitude 117° 20’ west) were found the marine fossils Harpoceras macclintocki and Monotis _septentrionalis. On North Cornwall (latitude 77° 30’ north, longitude 95° west) Belcher found vertebre of [chthyosaurus. Comanchic Period See plates 91 to 93 The highly emergent condition of the North American continent con- tinued into the Comanchic, and the only marine areas of this time were the widely extended formations in the Gulf of Mexico region and the re- stricted series along the Pacific. Continental deposits devoid of marine fossils occur in a limited area along the Atlantic Piedmont, but sediments of this nature with a far greater distribution are present in the northern Great Plains region and extend into Canada.?*® Table of Texas Comanchic Formations Washita series: Comanche Peak. Buda. Walnut. Denison (Del Rio). Trinity series: Fort Worth. Paluxy. Preston. Glen Rose. Fredericksburg series : Travis Peak. Edwards. a ae Gulf of Mexico area.—From Arkansas to southern Mexico occurs the greater development of the Comanchic or the “Lower Cretaceous.” The Comanche series was defined by Hill to embrace his Trinity, Fredericks- ‘burg, and Washita divisions. In central Texas the thickness of these deposits is about 1,500 feet, which increases to 4,000 feet of limestone to the southwest of Chihuahua, and is said to attain far greater depth in cen- tral Mexico.??" | _ Aguilera?** divides the entire Mexican “Cretaceous” into Eo, Meso, and Neocretaceous, because the series, being devoid of recognizable breaks in sedimentation, is seemingly a continuous one. The Eocretaceous of Mex- ico is not yet characterized paleontologically, but is thought to represent the Neocomian, Barremian, and Aptian of southern Europe. A good sec- 236 For a digest of the literature up to 1890, see White: Bull. no. 82, U. S. Geological Survey, 1891. 237 Hill: Bull. of the Geological Society of America, vol. 5, 1893, pp. 297-338. 238 Aguilera: Guide International Geological Congress, Mexico, 1906. 584 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA tion may be studied in the region of Zapotitlan and San Juan Ryan. In the Mesocretaceous, Aguilera includes the Mexican equivalents of the Albian and Cenomanian. The Washita is sometimes correlated with the Cenomanian, which is at the base of the European Upper Cretaceous, and Stanton informs the writer that he regards the Upper Washita as probably of Cenomanian time. The Comanchic faunas are mainly from calcareous sediments, and are distinctly Mediterranean or southern European (especially Portugal and Spain) in type. The echinoids present “a very familiar facies to a Euro- pean echinologist. . . . Several species are common European forms.” Out of six forms from Mexico described by Cotteau, “three are character- istic of the European Lower Cretaceous (Aptian and Urgonian), namely, Diplopodia malbosi, Salenia prestensis, and Pseudocidaris saussuret.”?** There is nothing in common with the decidedly different faunas of the Pacific border region of America. Each province develops distinct faunas out of the previous Jurassic assemblage.**° For this reason C. A. White and Stanton**? assume a complete land barrier along the Pacific, from California to South America, during the Comanchic. The oldest Comanchic fauna, and one that the Mexican geologists regard as older than the Trinity, occurs at Tehuacan, Mexico. It is a fauna of reef corals and thick-shelled mollusks. Some of the common corals are: Cryptocema cf. neocomiensis, Phylloceema cyclops, and Eugyra cotteaut. ‘There are also present the echinoid Pseudocidaris saussurei and the mollusks Fimbria corrugata ?, Ostrea acuticosta, Trigonia plicatocos- tata, Cryptogervilleia, Glaucoma bustamentu, G. cingulata, Nerinea cf. loculata, and Trachynerita nystt. | Stanton? states that the Trinity has the foraminifer Orbitolina and the following characteristic Mollusca: Trigomia stolleyt, T. crenulata, T. lerchi, Requienia cf. texana, Monopleura cf. marcida, M. cf. pinguiscula, Natica pedernalis, Glaucoma, brannert, G. cf. helvetica, and G. cf. pictetr. The Fredericksburg, the time of greatest inundation, is marked by the first abundance of Gryphea (several species formerly referred to G. pitchert) and Hxogyra. In the Lower Fredericksburg there are forms of Enallaster, Hemiaster, Epiaster, Holectypus, Schlenbachia acutocarinata, and S. trinitensis. In the upper part of the Fredericksburg the fauna of the southern region (Texas-Mexico) is in the main composed of Requi- 239 Gregory: Bull. of the Geological Society of America, vol. 3, 1892. 240 Stanton: Journal of Geology, vol. 5, 1897, pp. 579-624. : #1 Stanton: Ibid., 1909, p. 417. 244 Tbid., 1897. COMANCHIC PERIOD 585 enia, Monopleura, Radiolites, Nerinea, and corals, thus resembling that of the “Schrattenkalk” of the Urgonian. The Washita continues the Fredericksburg fauna, but the characteristic species are Pachydiscus brazoensis, Hamites fremonti, Schlenbachia of the type S. inflata, and Turrilites brazoensis. The Upper Washita is con- sidered basal Cretacic, and is so represented on the paleogeographic maps. Pacific area—In California Comanchie, or, rather, Shastan, time began with the Knoxville, a somewhat restricted marginal invasion with boreal or Aucella faunas. It was in the Upper Knoxville that more extensive in- undation took place to the north of the Sierra Nevada uplift—that is, it extended widely across Alaska, connecting the Pacific with the Arctic ocean. At the same time much of British Columbia was marginally in- vaded by the sea with a boreal fauna distinguished by Aucella crassicollts. At the close of the Knoxville, Alaska was again above the sea, thus shut- ting out the boreal waters with their northern faunas. In California the Knoxville has a thickness of from 12,000 to 20,000 feet. On Queen Charlotte islands the depth of divisions C, D, and E, referred to the Shas- tan, seems to be nearly 9,000 feet. According to Stanton,?** the fauna of the Knoxville is especially marked by an abundance of Awcella piochu in the lower beds and A. crassicollis in the upper 2,000 feet. He states that they are “so abundant that they must have actually monopolized the sea bottom.” Among Mollusca the Turbinide are noteworthy. The more characteristic ammonites are: Phylloceras knoxvillensis, Desmoceras californicum, Olcostephanus muta- bilis, Hoplites hyatti, H. storrsi, H. angulatus, H. crassiplicatus, and H. dillert. These faunas are correlated with the Neocomian. The faunas of the higher Shastan series or the Horsetown are at first much like those of the Knoxville, but the great changes in Alaska brought about by shutting out the boreal waters soon allowed the introduction of the Mediterranean faunas. Asa whole, the Horsetown fauna is remarkably distinct from that of the Knoxville, and the former can usually be identi- fied by the absence of Aucella. In its typical development this fauna, however, is restricted to northern California and Oregon, but late Horse- town time is represented as far north as Queen Charlotte islands. “Toward the close of the Horsetown the fauna was greatly modified by the introduction of many types that show relationship with the Cretaceous faunas of southern India, and also with those of Japan. This relationship was con- tinued in the succeeding Upper Cretaceous faunas to such an extent that it is appropriate to speak of an Indo-Pacific province or region.’’** 248 Tpid., 1897. 244 Stanton: Ibid., 1909, p. 415. L—BULuL. Grou. Soc. AM., Vou. 20, 1908 ! ~ ee SS oe eee ———— oo a i Lae ee es 586 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA In the Lower Horsetown the following are the more distinctive forms: Trigonia equicostata (also in Upper Horsetown), Phylloceras onoense, Hoplites remondt, Olcostephanus traskt, Desmoceras hoffman (also Upper Horsetown), Crioceras percostatus, and Ancyloceras remondi. In the Upper Horsetown, among other forms occur Ancyloceras lineatus, Haplo- ceras breweri, Lytoceras sacya, and Schlenbachia inflata. The Horsetown is correlated with the Aptian and Gault. Locally it seems to be deficient in continuous deposits into the higher Chico (Upper Cretacic), but Stan- ton regards this time break as of short duration. At least 10 of the Upper Horsetown species pass into the Chico of Cretacic time.*? Continental deposits——In eastern North America there are no marine Comanchic strata. The Potomac series is fluviatile or fresh water in character. The lower and thinner division, or the Patuxent-Arundel, is often correlated with the Morrison, which is generally referred to the late Jurassic or Wealden (see the Jurassic chapter). Berry has informed the writer that the Arundel is only a different phase of the Patuxent. The former lies unconformably upon the latter, but no marked value should be placed on this physical feature because of the fluviatile character of the formations. Furthermore, the iron-ore bearing Arundel is almost re- stricted to the region between Baltimore and Washington, and the plants are those of the Patuxent. Besides large cycads, the Arundel has yielded — dinosaur bones pertaining to Pleurocelus nanus, P. altus, Priconodon crassus, Allosaurus medius, and Celurus medius. The dinosaur remains are in harmony with those of the Morrison and Wealden, and according to present evidence these deposits are as well, or even better, placed in the Comanchic (also see page 582). The higher division of the Potomac series is known as the Patapsco, having a rich flora in which the angiosperms originate. This flora, how- ever, is still mainly ancient in aspect—that is, it consists chiefly of ferns, cycads, and conifers. The angiosperms do not become dominant until the Raritan and Dakota of the Cretacic. | In the northern Great Plains area are other fluviatile beds, first. de- scribed by G. M. Dawson as the Kootenai formation of Alberta. The thickness is given as about 4,700 feet, yet in Montana it 1s less than 600 feet. Locally it is coal bearing, there being in Alberta 22 workable coal — beds. The small flora may be compared with the Lower Potomac. There are also a few Unios and fresh-water gastropods, “mostly of simple mod- ern types.” | 2 Diller and Stanton: Bull. of the Geological Society of America, vol. 5, 1894, pp. 435-464. ———— P CRETACIC PERIOD 587 In the Black Hills and in Wyoming are other continental deposits known as the Lakota, Cloverly, and Fuson. In the Black Hills area about 1,000 large cycad trunks have been unearthed ; these are larger than those from the Patuxent of Maryland, but nearer them in development than the smaller ones from the Morrison of the Freeze Out hills of Wyoming. Knowlton informs the writer that these plant-bearing horizons practically have one flora, which corresponds best with the Wealden of Europe. It is closely linked with the Jurassic floras, as both have the same general aspect and a number of species are common to the two floras. Oretacic Period See plates 94 and 95 The widely emergent condition of the North American continent dur- ing the greater part of the Mesozoic was changed in the Cretacic. In the Comanchic most of Mexico was beneath the sea, and much of its eastern border so remained in the Cretacic, but here the invasion was far less than before. The decided submergence of Cretacic time began with the Dakota in the Gulf of Mexico area and spread north to the Arctic ocean east of the Rocky mountains. This formed the great Coloradoan sea, a syncline which with continental deposits first made its appearance cer- _ tainly as early as late Triassic time and was apparently due to the thrust- ing of the Pacific border region during the early Mesozoic. The faunas of this province are linked with those of the Gulf area and the Atlantic border, but the last two regions have far more in common than either has with the Coloradoan sea. The waters of the Gulf border and the Colo- radoan sea came into existence far earlier than the Atlantic overlap. A widely divergent faunal province occurs along the Pacific border from Lower California to Alaska. There were therefore two very distinct faunal provinces, and the one of the Atlantic is readily divisible into three sub- provinces—the Coloradoan sea, the Gulf of Mexico region, and the Atlan- tic border, the latter being most typical in New Jersey and Maryland. Throughout the Cretacic the Laramide range seems to have been in shght upward movement, with decided elevation toward the close of this period. The pressure coming from the Pacific folded the Cretacic de- posits, which in places are 20,000 feet thick. As a result of this move- ment, North America was again greatly enlarged, and for a short time was connected with South America, thus permitting some intermigration of the land animals of the two continents.?48 248 Hor a digest of the literature up to 1890, see White, Bull. no. 82, U. S. Geological Survey, 1891. 588. Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Table of Cretacic Formations | Colorado, Wyoming,and ‘| Western interior Atlantic Montana of Canada dlexas Gulf coast coast Break é= {Denver (2) Paskapoo Laramie 3) Arapahoe Edmonton Tn Break wa Break = f Bearpaw Bearpaw (Odanah) x | Judith River {| Belly River Navarro Break Jerseyian & > Montana| a Claggett | Ripley B Claggett (Melwood) a 2 Eagle ; Taylor @ Ripleyian Ay = | Selma Le Niobrara Niobrara Austin “| Eutaw (Up- tea } Colorado = per) ae y Benton Benton Eagle Ford = Break ee (Bear River) Dakota Dakota Woodbine Break Break Break | Mexico—tIn Mexico the late Comanchic or Washita submergence con- tinued unbroken into the Neocretaceous, according to the Mexican geolo- gists. An extensive and well exposed section may be studied along the line of railway between Cardenas and Las Canoas, going east from San Luis Potosi to Tampico. Here, according to Bose,?*® the Cardenas hme- stone has an approximate thickness of 1,800 feet. He correlates this hmestone with the Lower Senonian of Europe, and states that it rests on the Turonian or their Mesocretaceous. ‘The former fauna holds the hori- zon of the American Lower Montana, or, better, the Ripleyan. In the basal portion of the Cardenas formation are the Gryphea beds, with G. vesicularis, Hxogyra costata, and Ostrea aguilere. Higher up occurs the Orbitoides limestone, with Ostrea cf. goldfussi, Inoceramus cf. crispu, and corals. The upper member is the Coralliochama limestone, with C. boehmi, Radiolites austinensis, Biradiolites (3 species), Hxogyra costata, Ostrea glabra, Anomia argentaria, A. gryphorhynchus, and abundance of Acteonella, and corals. 'These faunas appear to be related to those of the lower division of the Blue Mountain series of Jamaica. Bose states that the Cardenas faunas are “in intimate relation with those of Europe, and especially with those having the mediterranean facies [as those of Gosau], but to it have been added some types of the fauna of the North. As already stated, however, our faunas are not always identical with those of Europe, but generally they are somewhat dis- tinct in character; there must have been a relatively rapid migration from 249 Bose: Bol. 24, Instituto Geologico de Mexico, 1906. te CRETACIC PERIOD o89 Europe to America, and as all our species lived near the coast this migration should have been effected largely by means of a continent or a series of islands, instead of the present Atlantic; perhaps a study of the fauna of Jamaica will demonstrate later that that place was one of the stations on the road over which the animals came. “In Europe the Gosau strata represent a mediterranean facies, and are nota- bly distinguished in their paleontological character from the Senonian of the north of Europe. In America we observe a surprising analogous circumstance. We have known for some time that the Cenomanian strata of Mexico and Texas represent a mediterranean facies, but the Senonian also represents an analogous facies in Mexico (and Jamaica ?). In northern United States—that is to say, in New Jersey—is found, according to Credner, a facies of the Senonian which corresponds closely with that of the northern part of Europe; on the other hand, the fauna described in this work represents a facies which corresponds fairly well with that of Gosau, in the way that the facies of the Senonian of northern America corresponds with that of the north of Europe.” The Cardenas fauna has little in common with the Cretacic of the United States. Of the Colorado, there is present Inoceramus labiatus, I. fragilis, and I. cf. simpsoni (also in Montana series), and of the Mon- tana Ostrea glabra, Anomia argentaria, A. gryphorhynchus, Gryphea vesicularis, and Hxogyra costata. The wide differences between the Cre- tacic of Mexico and that of the United States may be due in part to the decided limestone facies of the former region and perhaps more to latitude. The Colorado or Turonian faunal equivalents of Mexico have as yet not been described, other than the few forms mentioned above. Antiles.—On Jamaica, the oldest fossiliferous formations are those of the Blue Mountain series of about 5,000 feet thickness, with the base not seen. The Lower Division is Cretacic, while the Upper Division, or Richmond beds, is of Eocene age, according to Hill.2®° There are tuffs with some hard limestones and yellow clay, but most of the material “can be traced to igneous rocks,” deposits of a shallow sea, a “tangled series of tuffs and conglomerates.” In the lower part of the Lower Division the dominant fossils are rudistids, Acteonella, and corals. The corals which have been described are: Cladocera jamaicensis, Diploria conferticostata, Multicolumnastrea cyathiformis, Cyathoseris haidingert, Porites reussiana, and Leptophyllia agassizi. Of rudistids, there are Barrettia moniliformis, Radiolites (5 species), Caprina jamaicensis, Caprinella quadrangularts, C. occidentalis, and C. gigantea. Some of the rudistids are said to occur in the Upper 2509 Hill: Bull. of Museum of Comparative Zoology, vol. 34, 1899; also see Gregory, Quarterly Journal of the Geological Society of London, 1895, pp. 255-310. 590 C. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Division, associated with Eocene fossils (ibid., 129). It is probable that: the Blue Mountain series is also present on Haiti, Costa Rica, and Cuba. Apparently the same fauna occurs in northern Guatemala. Sapper?* mentions Barrettia and Spherulites. The formation consists of lime- stones, dolomite, limestone breccias, and gypsum, with some salt. The Comanchic echinoids of the Antillean-Mexican region, as has been seen, are very closely related to those of southern Europe, but in the Cre- tacic “the two faunas developed on independent lines.” This differentia- tion of the echinoids of the two areas continued into the Cenozoic.?** Colorado series—The vast area east of the Rocky mountains, from. Colorado to the Arctic ocean, which remained elevated throughout the Mesozoic, began to be invaded by the ocean during the early Cretacic. The southern Comanchic submergence had mainly vanished, and early in Dakota time the Gulf again spread toward the north. The submergence thus begun was continued northward rapidly during the Benton, and it is quite likely that at about the same time the Arctic extended southward and united with these southern waters. This, then, was the great inland Coloradoan sea, with its deposits resting unconformably upon various of the earlier formations. The Dakota fauna, as published, is a small one of brackish-water forms and Unios, with a few marine species. Stanton?*® states that “the fresh- water species show relationship through the genus Pyrgulifera with the fauna of the Bear River formation, which is apparently about on the horizon of or a little later than the Dakota. The Bear River fauna of C. A. White?>+ “is unique among western non-marine faunas in that it contains a number of types that have left no descendants in later forma-- tions of the region.” The flora of the Dakota has over 500 species, the: angiosperms being dominant throughout all the horizons. Succeeding the Dakota is the Colorado series, which is divided into a lower portion, the Benton, and an upper, the Niobrara, but not every-. where can this two-fold separation be maintained. The Colorado series is characterized by Inoceramus labiatus, and extends from the Gulf of Mexico probably to the Arctic ocean, yet in the Gulf area east of western: Arkansas and along the Atlantic coast no deposits of this time are known.. The diagnostic fossils of the Colorado are: Inoceramus labiatus, I. dimi- dius, I. fragilis, I. deformis, I. undabundus, Ostrea lugubris, Exogyra 251 Sapper: Petermann’s Mittheilungen, Erginzungsheft, 1894, p. 113. 252 Gregory: Bull. of the Geological Society of America, vol. 3, 1902. #3 Stanton: Journal of Geology, 1909. . 254 White: Bull. no. 128, U. S. Geological Survey. See also Stanton, American Journal of Science, vol. 43, 1892; Veatch, Professional Paper no. 56, U. S. Geological Survey,. 1908. CRETACIC PERIOD HOM columbella, Gryphea newberryi, Gervillia propleura, Cardium pauper- culum, Liopistha meeki, Glauconia coalvillensis, Pugnellus fusiformis, Baculites gracilis, Metoicoceras swallovt, Scaphites warrent, and the keeled ammonites Prionotropis, Prionocyclus, and Mortoniceras. The Colorado is also marked by the absence of Heteroceras, Ptychoceras, Anisomyon, large Baculites, and the broad compressed forms of Inoceramus, as I. sagensis and I. vanuxem.?°° The Niobrara chalk is typically developed only in eastern Colorado and Kansas, and thence northward into Manitoba. To the south it connects faunally through identical species with the Austin chalk of Texas, though in the latter formation the fauna is a larger and more varied one. To the west and northwest the Niobrara changes into shale, and it is then indistinguishable from the Benton, its fauna being here made up of Nio- brara and Austin forms, Benton derivatives, and local species. Montana series, western.—The Colorado series is followed without break by the Montana. The faunas of this series vary locally from typi- cally marine to brackish and fresh-water deposits. The marine life is a continuation of that of the Colorado with the addition of Arctic and. southern Atlantic migrants. Some of the more distinctive fossils are: Anisomyon borealis, Inoceramus sagensis, I. sublevis, I. crispu, I. tenui- lineatus, I. vanuxemi, Ostrea pellucida, Veniella humilis, Gervillia sub- tortuosa, Callista deweyt, Breviarca exigua, Mactra gracilis, Corbulamella gregaria, Amauropsis paludineformis, Anchura nebrascensis, Fasciolaria cretacea, Scaphites conradi, 8. nodosus, Placenticeras intercalare, P. whit- fieldi, Baculites ovatus, B. compressus, B. grandis, Heteroceras, and Pty- choceras. The lower part of the Montana series or, rather, the Pierre formation (Claggett and equivalents) is nearly everywhere typically marine, but in the western area of the Coloradoan sea, from central New Mexico into southern Athabasca, there is more or less alternation of coal-bearing brackish and fresh-water beds with local marine horizons. These in part are the Judith River-Belly River beds and the Mesaverde formation, unknown in the eastern area of the Coloradoan sea. Above this series, in the Bearpaw and equivalent formations, the marine deposits are again more widespread in the Montana. The invertebrates “fall into three gen- eral categories of marine, brackish-water, and fresh-water forms, the latter including a few more or less doubtful land shells.” The brackish-water fauna .contains Ostrea, Mytilus, Modiola, Anomia, Corbicula, Panopea, 25 Stanton: Bull. no. 106, U. S. Geological Survey, 1893, and Journal of Geology, 1909, p. 419. » 592 ~=©c. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Rhytophorus, and Goniobasis. As a rule, the fresh-water forms are found - in distinct beds associated with land mollusks and land vertebrates. The vertebrate life is very varied, but is largely composed of fragmentary ma- terial, in the main of turtles and dinosaurs. “When considered in its en- tirety, the vertebrate fauna of these beds is remarkably similar to, though distinctly more primitive than, that of the Laramie. Almost or quite all of the Laramie types of vertebrates are present, though, as a rule, they are represented by smaller and more primitive forms.””°° Eastern and southern or Ripley faunas of Montana tume.—Weller?** has recently redescribed the northern Ripleyian and Jerseyian faunas, con- sisting of about 600 forms. He states that “a considerable number of species have an extraterritorial distribution, and by far the larger number of these species which occur outside of New Jersey are known from the Upper Cretaceous formations of the Gulf-border region, in the Ripley and associated formations of Alabama, Mississippi, Texas, etc.” The relation- ship with the Montana is also close, but less than that of the Gulf border. Along the Atlantic border the Ripley faunas are introduced by deposits largely continental in character, which finally pass into marine beds. These are the Raritan-Magothy formations, with a flora of about 150 spe- cies. The marine faunas of these beds are small and rather of brackish- water types. The Tuscaloosa and Tombigbee are also correlated with the Magothy. In regard to the Ripley fauna, Stanton?®* presents the following sum- mary: “Toward the south in New Mexico the littoral facies of the Montana fauna blends with the Ripley fauna, which is well developed in the latest Cretaceous formations of Texas, Mississippi, Alabama, and throughout the Atlantic coastal plain to New Jersey. The Ripley and Montana faunas have many species in common. . . . In the Montana fauna the genus Inoceramus is very abun- dant and varied, and ammonoids—especially Placenticeras, Baculites, Seca- phites, and other evolute types—are abundant, while the Ostreidz, Veneride, Cardiide, etc., and many types of gasteropoda, including Volutidx, are greatly developed. The Ripley fauna is more varied and luxuriant, so to speak, than the Montana and apparently indicates a warmer, or at least a more favorable climate. . . . The Montana fauna probably received some of its elements directly from the Arctic, while the Ripley fauna came in from the Gulf of Mex- ico and the Atlantic. With the connection between the Atlantic and Pacific elosed in the Mexican and Central American region as at present, the Gulf stream would give similar conditions, and would distribute the Ripley fauna 236 Stanton and Hatcher: Bull. no. 257, U. S. Geological Survey, 1905. 237 Weller : Geological Survey of New Jersey, vol. 4, 1907. 28 Stanton: Journal of Geology, vol. 17, 1909, p. 421. 3 CRETACIC PERIOD 993 along the coast from Texas to New Jersey. It is noteworthy that the European fauna most closely related to the Ripley is found at Aachen in [northern] Germany.” : Pacific coast—In California the Horsetown of Comanchic age passes without break into the littoral Chico of the Cretacic. Many of the spe- cies are common to the two formations. In northern California the Chico consists chiefly of sandstone and conglomerate, with local zones of shales, the whole attaining a thickness of 4,000 feet. Wallala and Lower Martinez are other names included in the Chico. Division A of the Queen Charlotte series and the Nanaimo series of Vancouver (5,226 feet thick ; Comox, 4,912 feet) are the northern equivalents of the Chico, all three being united by a common fauna.”°® With the exception of Gry- phea vesicularis, Inoceramus digitatus, I. labiatus ?, and possibly a few other species of bivalves, there is nothing in common between the Pacific faunas and those of the Coloradoan sea. All these forms either have a long range or are widely distributed species. None of the Pacific coast faunas are thought to be younger than the Pierre, and the faunas of the next formation, or Tejon, suggest the Claibornian of late Eocene time, but are usually regarded as basal Eocene. In some places the Chico and Tejon are disconformable with one another, but in general there is angular unconformity between them, showing that the Laramide revolution is as well indicated here as in the deposits of the Coloradoan sea.?°° Some of the more characteristic fossils are: Trigoma evansana, Cu- cullea gravida, Pectunculus veatchi, Caryatis mtida, Pharella alta, Cymbo- phora ashburneri, Inoceramus whitneyt, Coralliochama orcuttt, Actwon inornatus, Anchura californica, A. falciformis, Scobinella dilleri, Rostel- lites gabbi, Gyrodes expansa, G. conradiana, Pugnellus hamatus, Perisso- lax brevirostris, Acanthoceras turneri, Helicoceras (?) vermicularis, Pachydiscus newberryanus, Schluteria jugalis, Schlenbachia chicoensis, and Baculites chicoensis. Stanton? states that “No ammonoides have been found in any collections from the Tejon made since Gabb’s time. “The affinities of our west coast Cretaceous faunas are much closer with those found on the opposite side of the Pacific, in southern India, Japan, and Saghalien, than with the Cretaceous faunas in the United States.” 299 Whiteaves: Mesozoic fossils, Geological Survey of Canada, vol. 5, 1903; lists a fauna of 168 species, on pages 314-407. 260 See Diller and Stanton: Bull. of the Geological Society of America, vol. 5, 1894. Stanton: Seventeenth Annual Report of the U. 8S. Geological Survey, part i, 1896, pp. 1011-1060. Merriam: Journal of Geology, vol. 5, 1897, pp. 757-775. Weaver: Bull. of the University of California, vol. 4, 1905, pp. 101-123. - 261 Stanton: Ibid., 1906, pp. 1031-1034. 594 Cc. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA The Chico is also present in Alaska (Lower Yukon and Alaska penin- sula), but as yet very little is known of the marine fossils.?° The close of the Cretactc.2**—The Laramie is the last of the conform- able Cretacic series of the Coloradoan sea. Its formations consist of alter- nations of brackish water and continental deposits. Stanton?* states: “The brackish-water species have survived from earlier formations in the same region by living in the marine waters or advancing with the sea margin when the submergence came. The fresh-water types must have been preserved in the streams of the adjacent lands when marine or even brackish waters covered the larger part of their habitat. A considerable number of fresh-water types were thus enabled to survive into the Tertiary. . . . With the brackish-water forms of the Laramie the case is different. . . . In areas of non-marine deposition where the line between Cretaceous and Hocene has not been sharply drawn, because the erosion plane that is supposed to separate them has not yet been located, the occurrence of an oyster bed, or a stratum full of Corbula, is sufficient evidence that the rocks are still Cretaceous and below the major unconformity that separates Cretaceous from Tertiary.” During the past few years a discussion has been going on among stratigraphers, in which the opinions centering around “What is the Laramie?” and “The systemic age of the Ceratops beds” differ consider- ably. In the field, geologists have pointed out erosional unconformi- ties which they believe to be of wide extent and of the greatest impor- tance as representing an interval of long duration. The strata above this unconformity are said to contain the Fort Union flora of Kocene age,. and also the well known Ceratops fauna of dinosaurs associated with archaic mammals. Geologists therefore maintain that these formations are basal EKocene, and that the distinctive Cretacic land animals persisted’ into Eocene time or the Lower Fort Union, but were soon and almost sud- denly extinguished in the Upper Fort Union in Colorado, Wyoming, and Montana. Throughout a large area in Wyoming and Montana the latest marine Cretacic strata of this region are overlain by a formation that is not typically marine, composed of light colored sandstones and darker sandy shales. This formation has been called “Ceratops beds of Converse county,” “Lance Creek beds,” “Hell Creek beds,” “Laramie,” etcetera. 22 Stanton and Martin: Bull. of the Geological Society of America, vol. 16, 1905, pp: 408-409. 263 The literature on this subject is as follows: Cross: Proceedings of the Washington Academy of Sciences, vol. 11, 1909, pp. 27-45. This paper gives references to all others: bearing upon this discussion. Knowlton: Ibid., 1909, pp. 179-238. Stanton: Ibid., 1909, pp. 239-293. Hatcher and Lull: Monograph 49, U. S. Geological Survey, 1907. Brown = Bull. of the American Museum of Natural History, vol. 23, 1907, pp. 823-845. 64 Stanton: Journal of Geology, vol. 17, 1909, p. 423. CRETACIC PERIOD 595 The floral evidence has recently been summed up by Knowlton, who refers the Ceratops beds to the Lower Fort Union of Tertiary age. He states: “It is shown that the lower member rests, in some cases unconformably, in others in apparent conformity, on the Fox hills or Pierre, and the conclusion is. reached that an erosional interval is indicated during which the Laramie—if -ever present—and other Cretaceous and early Tertiary sediments were removed. “Tt is shown that the beds under consideration, being above an unconformity, can no longer be considered as a part of the ‘conformable Cretaceous series,’ and hence are not Laramie. “The final conclusion is reached that the beds here considered (‘Hell Creek. beds,’ ‘somber beds,’ ‘Ceratops beds,’ ‘Laramie’ of many writers) are strati- graphically, structurally, and paleontologically inseparable from the Fort Union, and are Eocene in age” (237, 238). Stanton has reviewed the stratigraphy and paleontology of these beds from another standpoint, with the result that “the Ceratops beds are of Cretaceous age.” His evidence sums up as follows: “The ‘Ceratops beds’ with the Triceratops fauna are always pretty closely associated with the uppermost marine Cretaceous strata or are separated from. them by transitional brackish-water beds. They are always overlain by a thick. series of rocks containing a Fort Union flora in which no dinosaurs have been: found, and in the Fish Creek, Montana, region this overlying series also con-- tains primitive mammals related to those of the Puerco and Torrejon faunas. “Throughout a large part of the area no evidence of an unconformity be-- neath the ‘Ceratops beds’ has been found, while higher in the section uncon-- formities have been demonstrated or suggested at a number of places. Uncon- formities have been reported below the ‘Ceratops beds’ on Hell creek, Montana, on the Little Missouri in North Dakota, and in Weston county, Wyoming, but in none of these cases has any proof been furnished that the erosion interval is: important [279]. “Soon after the Benton, however, large areas west of the Front Range in: Colorado and Wyoming and west of the 108th meridian in Montana previously covered by the sea began to emerge, either by uplift or by filling of the basins with sediment, and as they came up to sealevel or a few feet above it land and marsh flats became established and all the conditions became favorable for the formation of coal beds. Land animals also came in and the streams and’ fresh-water lagoons received their appropriate population from adjacent areas,. while the bays and estuaries were inhabited by brackish-water forms. The neighboring land-masses must have formed large areas and have had con-. siderable elevation in order to furnish the immense thickness of Upper Cre-- taceous sediments known in this region (280). “There were oscillations, so that occasional brackish-water or marine deposits were brought above those of land and fresh-water origin, and it is probable that these oscillations were not always synchronous throughout the region. Locally, as in part of Bighorn Basin, this non-marine sedimentation may have: been almost continuous until the end of the Cretaceous, but over most of the- area there was a more important subsidence which brought the marine sedi- 596 C. SCHUCHERT——-PALEOGEOGRAPHY OF NORTH AMERICA ments represented by the Lewis and Bearpaw shales over the coal-bearing for- mations. “As far up in the series as brackish-water fossils are found they occur in usually thin beds intercalated amongst the fresh-water strata, showing that the two elements of the fauna had separate habitats. . . . These mollusks evidently lived in tidal waters connected somewhere with the open ocean” (281, 282). Ab The most interesting biological side of the question connected with these beds is of course furnished by the wonderful dinosaur assemblage, among which the Ceratopsia are the more conspicuous because more com- monly found. These forms have been well described by Hatcher. and Lull. The dinosaurs represented are: Triceratops horridus, T. flabellatus, T. prorsus, T’. serratus, T. sulcatus, T. obtusus, T. elatus, T: brevicornis, T. calicornis, Diceratops hatcheri, Torosaurus latus, and T. gladius, as well as Trachodon, Tyrannosaurus rex, and Ormthomimus. The mammal remains are very fragmentary, and all pertain to archaic forms—that is, Mesozoic types—which also range into the basal Hocene beds. The dino- saurs, however, are as yet not known to range above the Cretacic. The fresh-water mollusks are varied, the fauna consisting of about 25 named species of Unio, together with Anodonta, Spherium, Corbicula subelliptica, Vwiparus, Tulotoma thompson, Campeloma (several spe- cies), Thaumastus, Goniobasis tenuicarinata, Physa, Helix, Limnea, and Bulimus. This fauna is quite distinct from all those of the same habitat which succeed it in the American Eocene. The brackish-water faunas have Ostrea subtrigonalis, O. glabra, Corbula subtrigonalis, C. undifera, Corbicula cytheriformis, C. subelliptica, C. occidentalis, C. fracta, Anomia micronema, Neritina baptista, N. volvili- neata, Melania wyomingensis. These are likewise Cretacic forms. Of land plants, in Converse county alone are 48 named species, of which’ 5 are figs and 2 are palms. The flora indicates a subtropical climate. In this connection it should be stated that the floras of the late Cretacic and Eocene show no marked differences, the change being one of species, not of different families and genera (information supplied by Knowlton). The vertebrate evidence shows close relationship with that of the Judith River fauna, which is known to be Cretacic, and lies beneath a thousand feet or more of marine Cretacic beds. ‘The whole fauna of the Ceratopsia beds is decidedly Cretacic, and there is nothing to suggest the Cenozoic unless it be the archaic mammals, of which two or three genera are also known in the Torrejon (Eocene), where the mammals, and those of the Puerco (Eocene) as well, are all of Mesozoic origin. CRETACIC PERIOD 597 The fresh-water fauna is composed of existing genera, which in them- selves are not of much stratigraphic value. Taken in connection with the local stratigraphic sections in which they oceur, however, it is seen that the formations are intimately bound with those of unmistakable Cretacic age. Again, the Unios are unlike those of the Eocene in that the umbos of the shell are often sculptured. The brackish-water faunas are certainly those of the marine Cretacic, and the succession shows that these finally vanish from the interior region, the Cretacic series going over completely into fresh-water beds of a continental character. Nowhere has the marine Tertiary entered this region, and the nearest Eocene sea did not advance beyond Tennessee or coastal Texas. Stanton concludes : “The Gatatope beds’ are of Grecigcote age as decided by stratigraphic rela- tions, by the pronounced Mesozoic character of the vertebrate fauna with ab- sence of all Tertiary types, and by the close relations of its invertebrate fauna with the Cretaceous. The relations of the flora with Eocene floras is believed to be less important than this faunal and stratigraphic evidence. Taken in their whole areal extent they probably include equivalents of the Laramie, Arapahoe, and Denver formations of the Denver Basin.” “The Fort Union formation, properly restricted, is of early Eocene age, the determination resting chiefly on its stratigraphic position and its primitive mammalian fauna which is related to the earliest Eocene fauna of Europe. The very modern character of the flora tends to confirm the correlation” (2938). TERTIARY OR NEOZOIC (CENOZOIC) ERA See plates 96 to 100 Familiarity at first hand with the Tertiary formations requires a vast amount of detailed knowledge of the plants and land animals, and espe- cially of the marine invertebrates, which the writer does not possess. In order to make the paleogeography of North America as complete as possi- ble, however, he has devoted his efforts toward the compilation of the maps and the table of formations more for the benefit of teachers of historical geology than for stratigraphers. With the maps he has had the assist- ance of Dall, Arnold, and Vaughan. The more important literature pertaining to this era is as follows: Dall and Harris: Correlation papers—Neocene. Bulletin 84, U. S. Geological Survey, 1892. Dall: A table of the North American Tertiary horizons, ete. Eighteenth Annual Report of the U. S. Geological Survey, 1898, pages 323-348. Contribu- tions to the Tertiary fauna of Florida, parts I-VI, 1886-1903. Transactions of the Wagner Free Institution of Science, Philadelphia. - O9$ | Period Neogenic Hogentc C. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Table of Tertiary £2] 8 | Middle Atlantic States Gulf States ‘Pacific Coast a3) 3 = 3 Talbot Columbia Kowak 5 Colum- mA ‘ ; = bia: Wicomico Ground ice oO Sunderland | Cornfield Harbor San Pedro—Coos a Break 2 Lafayette Lafayette Merced—Paso Robles 2 Mytilus—Deadman Island = Break Caloosahatchie—Croa- San Diego or ' ton—Waccamaw Purisima—Cholame by Cha s (San Pablo—Snooke Duplin—Suffolk S. | Empire 2 _ Yorktown Pascagoula > (Santa Margarita a = Saint Marys Alum Bluff—Chesa- iS 4 Choptank— peake Break si 2 ; James River = 4 Calvert—Peters- # (Monterey (? Modelo) 3 | burg E | Yacawers. © | Shiloh HI Pasadena r= = Oak Grove (Bowden of S Jamaica) San Lorenzo es 3 Chipola Tunnel Point a ra Chattahooche (Grand | Astoria = S Gulf—Tampa) Aturia = < | Absent 5 —= pas Ocala > Penin- ¢ Vicksburg Kenai of Alaska ae Sular Red Bluff — |_—_ 2 = 2 Zeuglodon—Santee | 9 Absent Moodys Branch | a Marks Mill 5 z Upper White Bluff S | Break Claiborne = Ostrea sellefor- P=) 5 mis s be Woodstock 2 Lisbon hE E A | valtanatta Break 5 =) s (Toke = a Potapaco Hachetigbee ? Little Falls S Paspotansa = | Woods Bluff 3 a! = (Bashi) Tejon-Arago—in g = 4 Bells Landing part Puget iS < | as (Tuscahoma) eS | Piseaey 2 Greggs Landing a — | Nanafalia Sy S4 y + | Break Naheola Upper Martinez— Ss? Sucarnochee Puget 7 Midway Break or —————— TERTIARY OR NEOZOIC ERA 599 Neozoic (Lyell) Formations ee Great Plains = Mammal Zones European analogues, Sa De Lapparent’s Traité 2 Champlain 3 Glacial Sheridan—Rock Creek S Equus Sicilian Loup River—Archer— a : : Ast Blanco a Glyptotherium a Plaisancian i Ogalalla—Clarendon f a Protohippus—Procamelus Sarmatian—Pontian = as et = ; Pawnee—Deep River a ~ sy Ticholeptus Helvetian—Tortonian ct } — a g Sosa Meryicocharus S J darrison—Rose a Diceratherium Burgidalian >) Bud a < =) | ai S - Upper Brule i] Leptauchenia Aquitanian ~ i = Protoceras - | Lower Brule 2 Oreodon—Metamynodon Stampian (Tongrian) joey a5 | es Chadron Titanotherium Sannoisian (Ligurian) Break Ludian Uinta Diplacodon Bartonian z : ra Washakie = Hobasileus Bridger Uintatherium Lutetian Wind River—Green River— Orohippus Huerfano Bathyopsis Ypresian (Londinian) é Lo} oe Knight 3 Lambdotherium es Fowkes © Coryphodon—Hohippus Sparnacian =« | Almy n Break _— Z = iWork Union Torejon Pantolambda Thanetian Puerco Polymastodon 600 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA Gregory : Contributions to the paleontology and physical geology of the West Indies. Quarterly Journal of the Geological Society of London, 1895, pages. 255-310. Clark: Correlation papers—Eocene. Bulletin 83, U. S. Geological Survey, 1891. Maryland Geological Survey, Hocene, 1901; Miocene, 1904; Pliocene and Pleistocene, 1906. Osborn and Matthew: Cenozoic mammal horizons of western North America. Bulletin 361, U. S. Geological Survey, 1909. Arnold: The Tertiary and Quaternary Pectens of California. Professional Paper 47, U. S. Geological Survey, 1906. Environment of the Tertiary faunas: of the Pacific coast. Journal of Geology, 1909. THE NEW GEOLOGIC TIME TABLE On the basis of the paleogeography here presented and the diastrophism postulated by these maps, two curves have been developed, showing the amount in square miles of the various inundations throughout geologic time since the beginning of the Cambric. The upper curve of the chart (plate 101) is based on the land area of the North American continent as at present emerged, which is estimated to be about 8,200,000 square miles im extent. Since vast areas of the continent are not well known geologic- ally, it was thought that errors might occur which would be detected were another curve calculated for the region best known—that is, the United States and a part of southern Canada, or the area between 30° and 50° north latitude. The square mile content of this space is calculated to be a little more than 3,530,000, the fluctuating inundation of which area is illustrated by the lower curve of the chart. A comparison of these two curves shows that they are very much alike, but that the upper one based on the greater area has the nodal points far more accentuated than the lower one based on the smaller-but better known area. It is therefore probable that no marked errors, such as additional periods or differently delimited periods, exist In regard to the North American continent. In the chart the vertical lines or abscisse are 80 in number, represent- ing 57 different paleogeographical maps (52 are here published) and 23: other time divisions. These are named in the lower part of the chart, and according to the present acceptance of them are grouped in periods or systems and eras. For the 57 maps, the amount of inundation is that calculated from these maps, while for the other time divisions the amount is estimated. In the former case the lines of the,plotted curves are drawn straight, and in the second instance they are wavy. The time ratios are based on Dana’s estimates somewhat changed, giving 12 to the Paleozoic, 6 to the Mesozoic, and 2 to the Tertiary. The time in years is prac- tically based on Walcott’s estimate of 1894 (Proceedings of the American NEW GEOLOGIC TIME TABLE 601 Association for the Advancement of Science). It will be seen that much more time has been allowed the Cambrian and Ordovician than is usually assigned them ; together they are allotted 43 per cent of the Paleozoic era. The per cent of time for each period is stated throughout, but it should be noted that these are rough estimates and not calculations based on the known thickness of the formations composing the periods or systems. The great length of Triassic time is based on the long and nearly com- plete Mediterranean record. The horizontal lines or ordinates numbered 1 to 8 on the chart each represent one’ million square miles of the North American continent. The two other horizontal lines give the areas for the “United States” and “North America” as explained above; hence the extent of the inunda- tions illustrated by the curves may be seen at a glance in relation to present conditions. A detailed analysis of these curves shows that there have been 17 lows, or inundations, separated from one another by as many highs, or emer- gent periods. Of these, 11 are Paleozoic, 4 Mesozoic, and 2 Tertiary. For easy reference, these are arranged in the following table, the amount of area submerged being given in square miles, with the percentage. The names in italics represent the marked submergences, 10 of which reach over 20 per cent. Table of North American Inundations Pantiilandare EAI Present land area of North America between nS store hmericn, about sae Om Time of greatest inun- In square | In per Time of greatest inun- In square [In per dations. miles. cent. dations. miles. cent. Middle Georgic....... 1,451,000 | 17.6 || Middle Georgic...... 421.000 | 12.0 Middle Acadic......... Doo RO0O! | Slo.) Middle Acadia... 02 0. 1,648.000 | 46.7 migodie Ozarkic........ i OOO 27 WiMaddle Ozarkie2) a2. 3. 1,016,000 | 28 9 Beekmantown ......... 1,663,000 | 22 7 || Beekmantown........ 1,065,000 | 30.3 oe Urenton.........| 4,676,000 | 57.2 || Barly Trenton........ 2,158,000 | 61.2 more hichmond........ 3,340.000 | 40.0 || Late Richmond......- 1,560,000 | 44.3 _ Se 2,940,000 | 35.9 || Louisuille...... Aes 1,246,000 | 35.7 ONMUILON. os... ee ee PASS OOO ooreen || MEROIDULOT. sei. oe eek 1,126,000 | 32.0 ESELUMGTON 2.55.0 05.05- Z O44 O00) |) ZO eB unlingioni... ci. «0 © 874,000 | 24.8 Sem WOuIS........... ~ 620,000 TeOM IS alliteleOUISss ee ccs 348 000 | 10.0 Hate Potismillian....... 2,219 QOOMRZTae | bate Potisnllian. 2). 1,283,000 | 36.4 Wate Iriassic......... 126 OO0n ior Slate Mi niassicasn. . .c.. 292,000 | 8.4 Wace SuULrassic......... PS O000N Sion oo eace rs MrASSI@ . 3... 646,000 | 18.4 Mredericksburg....... 1,559,000 | 19.0 | Hrederieksburng?. 3.5: 433,000 | 12.4 Niobrara (estimated)..| 2,778,000 | 33.9 || Niobrara (estimated) .| 1,354,000 | 41.3 Karly Oligocene...... 236,000 | 2.9 || Early Oligocene ....| 154,000 | 4.5 Upper Miocene....... 360,000 | 4.4 || Upper Miocene...... 234,000 | 6.7 LI—BULL. Grou. Soc. AM., Vou. 20, 1908 602 Cc. SCHUCHERT—PALEOGEOGRAPHY OF NORTH AMERICA Of the 17 submergences, 10 are marked ones, having inundated either of the two defined areas more than 20 per cent. In the Trenton the sub- “mergence covered about 60 per cent of North America. It is also seen that of these 10 decided submergences, 9 occurred during the Paleozoic, while the tenth took place during the close of the Mesozoic. The 7 smaller submergences inundated the areas from 2 to 19 per cent. The first of all these floods (Georgic) is classed in the so-called secondary inundations, and records the beginning of the Paleozoic. However, it is the most marked of the minor submergences, and is followed by 8 primary and successive inundations. Another minor flood (Saint Louis) then appears, which is succeeded by the last of the greater Paleozoic submer- gences. Jt may therefore be said that all the Paleozoic inundations except one (Saint Louis) are of the major type. Further, the Paleozoic submergences attain their maxima in the Ordovicic, each subsequent flood being of smaller extent. These facts seemingly furnish decisive indica- tions that during the Paleozoic the oceanic areas had not yet attained their present abyssal depths, and that outside the eastern border region the North American continent was a low, featureless land-mass through- out this era. The slightest secular or aggradational change anywhere on the globe then affected the oceans more than at any later time, so that they readily flowed widely over the lands, thus developing the very shal- low continental seas. In a general way, it may be said that the present broader relations of the oceanic areas to the lands have been fixed since the Appalachian revolution of the Atlantic realm. It is becoming more and more apparent that the geologic chronology for the greater divisions must be based on criteria additional to those now in use. In chronology, dependence will always have to be placed pri- marily on the fossil content of the sediments. In correlating the more or less similar developments of the various faunal provinces, however, some physical basis is needed underlying the faunal likeness or dissimi- larity. Such a principle apparently exists in the submergences or the positive changes of the strand-line, for when one of these attains its max- imum of spread, the widest distribution of similar faunas and identical species would naturally be expected. Conversely, the maximum of emer- gence must mark the absence of faunas in most land areas, followed for a time by more or less dissimilar faunas in all the provinces. As long ago as 1883, Suess concluded that the geologic time table would eventually be based on diastrophism and the faunal changes caused by these movements in their physical environment. He states: “It is the physical causes of faunal transformations which will, when once they are NEW GEOLOGIC TIME TABLE 603 recognized, form the only true basis for a delimitation of chronological periods.’’°* Diastrophism as determined by the successive faunas and their plotting on paleogeographic maps seems to include the physical principle that will not only render the formations of a province capable of being grouped into periods, but will serve as a fairly reliable guide for intercontinental correlations of like and unlike faunas as well. If the principles of diastrophism and paleogeography are to be made the basis for the future delimitation of periods or systems, the personal equation of workers in regard to the period value to be given this or that fossil or fauna is reduced to a minimum. In such a classification the disposition of a newly discovered horizon will adjust itself automatically on the basis of its paleogeography. If such maps can not be made, however, and the local conditions are not final, then temporary adjustment must of course be based on faunal affinity. With these principles as a basis, the curve chart (plate 101) has been constructed, and from it may be seen that since the beginning of Paleo- zoic time there have been at least 17 inundations, and that these are separated from one another by an equal number of high nodal points or emergent periods. On the chart, therefore, a period or system embraces the time represented by the space between two high nodes of the curves, including one more or less long low, or inundation. This method has been used by the writer?’ since 1902, when he stated that “each system should begin with a subsidence and end with an emergence.” According to the geological text book of Chamberlin and Salisbury, the geologic column has 13 systems, if the Tertiary is divided into two periods, as is now generally the practice. From the chart herewith pre- sented it is learned that there are 17 sutmergences, or lows, and it would seem, therefore, that the inherited classification is not borne out by the newer principles of paleogeography and diastrophism. A closer analysis of these curves, however, brings out the fact that in general the eras have hitherto been correctly defined, but that in detail the periods must be newly delimited in a number of places. The most marked of these changes is the division of the Cambrian and Ordovician each into three periods and the Mississippian into two periods. The bases for these major changes are described elsewhere in this work, while the new delim- itation of the old periods is indicated at the top of the chart. Of less importance are the following results: On the sole basis of the diastrophic curve for the “United States,” it is still debatable whether 266 Antlitz der Erde, vol. 1, 1883; Sollas translation, vol. 1, p. 14. 267 Ulrich and Schuchert: Report of the New York Paleontologist, 1902, p. 659. 604 Cc. SCHUCHERT—-PALEOGEOGRAPHY OF NORTH AMERICA the Siluric should close with the Manlius or with the Oriskany. During this entire time there was very little inundation, the small seas were oscil- latory, and there was no decided positive or negative movement of the strand-line. An analysis of the upper curve, however, shows that the Manlius was the last formation of the Siluric, being the highest point of the emergence, and that while the strand-line during the Helderbergian and Oriskanian was positive, it was not markedly so until the Onondaga. Taking all the facts into consideration, however, this upper curve proves — to be in harmony with the later views of the majority of European and American stratigraphers. The writer therefore regards the nodal point on this upper curve as the best expression of the more natural division between the Siluric and Deyonic. During the past ten years the dividing line between the Devonic and the Mississippic has also been debatable in America, but the two curves of the chart, when considered in combination, unfortunately furnish no definite answer to the problem. The difference between the two curves is due to a lack of detailed knowledge as to the areal distribution of the Chemung and Bradfordian equivalents. The lower curve is thought to more nearly represent the truth than the upper one, in which the deposits of Bradfordian time fall into the Mississippic period. According to the upper curve, however, this epoch is Devonic, but not much dependence should be placed on this portion of the curve, for as yet: this interval is practically unknown in the Cordilleran sea. Disregarding the minor ups and downs of the two curves, it may be seen that all the deposits from the base of the Helderbergian to the close of the Keokuk belong to one great diastrophic cycle. In the end this view may be found to be the correct one, but until more of the paleogeography of the world is deciphered noth- ing decisive can be said at this time. Should this view finally prevail, the term Mississippian will even then be found useful. The new period Tennesselc is borne out by both curves, but is espe- cially emphasized by the upper one. Neither curve, however, is thought to be expressive of the actual amount of inundation, because knowledge of the areal distribution of these deposits is as yet not exact. In any event, enough is known of these formations, of their faunas, and the dias- - trophism indicated by their areal spread, to denote a general movement, both negative and positive, of the strand-line. Beginning with the Pottsvillian, the strand-line became decidedly positive throughout America, with its maximum at the close of this epoch. Then very slowly the tide turned, and there was continuous emer- gence to the close of the Permic. On this basis alone there is no NEW. GEOLOGIC TIME TABLE . 605 Permic cycle in America, and all the Coal Measures, including the Guada- lupian, belong to one period. The determined chronology of these de- posits, however, must be based upon European paleogeography of these formations. It must therefore be understood that the dividing line on the chart between the Pennsylvanic and the Permic is hypothetical, being based on a supposedly correct interpretation of the European standards and of geologists. The highly emergent condition of North America at the close of the Paleozoic continued into the Mesozoic, and endured for a long time. The earliest and best marine records of the Triassic and Jurassic occur solely along the Pacific, but late in the latter period much of eastern Mexico sank beneath the Gulf. For these reasons, it appears that the chronology is here again dependent on that of southern Europe. In a broad way, however, it is seen that the two curves on the chart record decided inun- dations toward the close of the Triassic and Jurassic. Elsewhere in America there are no marine deposits, and the interval between the Per- mic and the Comanchic has long been well labeled the Jura-Trias. The Cretaceous is seen to contain two diastrophic cycles—the Co- manchic and the Cretacic periods. Both are recognized by Chamberlin and Salisbury in their “Geology.” Tertiary or Neozoic time also divides into two diastrophic cycles agree- ing with the recently proposed terms Eogenic and Neogenic (see De Lap- parent’s Traité). At the top of the chart has been placed the new classification, the divid- ing lines being so drawn that these eras and periods may be easily com- pared with the older scheme shown at the base of the chart.- In conclu- sion, the results here presented, contrasted with the previous classifica- tion, are as follows: 606 C. SCH UCHERT—PALEOGEOGRAPHY OF NORTH AMERICA The New Geologic Time Table Old classification | Cambrian Ordovician or Lower Silurian PRIISOAOIGs bo 45- . Siluric | Devonic | L Pennsylvanic- Permic ( Triassic IMIESOVAONC 55456500 Jurassic I L Cretaceous Eocene Oligocene Tertiary or Ce- WOZOIC eee Miocene lliocene Pleistocene Mississippian or Sub-Carboniferous New classification Georgic Acadie Ozarkic or Cambric Ordovicie Cincinnatie Canadie Siluric Devonic Mississippic Tennesseic Pennsylvanic- Permic Triassic-J urassic { Comanchic Cretacic \ Eogenic Neogenic > Paleozoic + Neopaleozoic | r Mesozoic J \ Neozoie BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 50 NORTH AMERIGAN PALEOQGEOGRAPHY BY CHARLES SCHUCHERT 1909 > _ i _ _—_ccm—€- EXPLANATION OF SYMBOLS. LANDS ARE WHITE. WATER AREAS ARE LINED. FORMATION OUTCROPS SOLID BLACK OR DOTTED. KNOWN SHORE-LINES ARE SOLID LINES; PROBABLE ONES BROKEN PAGE Gy VIM ASR INGE QQ areanric marine MUUMIMI. «cute marine Rae Wil Gn MiVAL RRelsN MARINE GYPSUM, OR SALT OR BORA INTERBEDDED MARINE & CONTINENTAL DEPOSITS CONTINENTAL Bee eS) 1S MOE ANG. se an rR US IVES EXPLANATION OF SYMBOLS _ a res ant f or Ry ste peed. | ‘1 5s yi < © r . t ie , ; . ‘ 7 ‘ 4 , - \ f a ’ 7 ‘ . H f , , 7 sae ¥ - =, " ’ ae S ve ™ p > Ww ‘ “ 1f a ey ho LF. ~ fe ELE, 3 =) aS ° y] Y id, \ SR a g x - . YY, = WS \ 4, iy 2 —\ DX rif\p A Y 4 > — ip) rd Db A “ ty A AY \,/ es ae he ~ Foal a BAS S LN 07 ee PS TD aC N S UJ i J alll} a % s oY xf | gn ZNSE ss JZ 77 95 90 ee’ a Cy 3 22 = — a am paw == a ZZ ——e CI i a ——- LJ = Z Zz = = 7 ras 77 = 2 [] —— o_o 2 so = ZZ SZ = Zs 2 2 = ——— > —————5 i> A KX bien NAS MH UNENANSNS HENS \ vill wt : . AM. 0 75 80 85 SS SSS ES See ee VOL. 20, 1908, PL. 52 ” | h I 75 80 BULL. GEOL. SOC. AM. R Yee YY p pe RIN Nee ee S RSV) NRE 0 . » j N Sy >) ASSN SN Nd 4) d N ‘ ~, x A \S a Ss —) Q 4 i P a i Zz \ : E a x SSS Se. SS ee See ee eo 0 SSS eS ee SSeS eS eae 7 J wa = Z3 a Zs i ay ws SZ py —6 i rx a zy r we Z 5 a j Dp Serre |. 1 LAE Py. RN NY SN on a LX Nee WAS SSN iP —— =i NORTH AMERICAN PALEOGEOGRAPHY By CHARLES SCHUCHERT, 1909 ° b UPPER ACADIC Nai i Ly, nl L of: é <7 (~) {/ roy q 2 o | ro: _ ag SY, of \s NS; 5 oe P pb x = e © ¥ \ pe NY > SW 4 “) iB QO ma — Atm <=: 7 — i == Sis ==. A A) — r=! - a a Le — qa LZ \ ned pes ‘ /’ N SRT LP O \ DK Ss Ne See \ \ MG u 4 Bt fi a ‘ Ms 6 L. Sy R = Fn a EEO =X 1’ 7G eS AKL Q ai ¢, AP \ 2 ‘KY \ S 9 ) + A My ; Us \ 7S 2) ~— ee {~——. ic} r ae iJ) o i--} / A) ‘Caw enh ) b eth s of xf i’) \j | pera Kl N PALEOGEOGRAPHY < MERIC < ‘ . AM. | oO 75 80 \_— SS J \4 ] g, Wika ras [A yy > \ WO Vy Y Lys wa y On SG : A y hD J Yq 4 [\ Nee. = ey oe: YZ: —— am ELD.) {| Caerraen 'o \S~ 3 bee = tA fl A ‘ y 4A Y } 3 ii & q ~Sz, Sn L) N \ (7 > Can y \\ ey ScaieN y oe ( \ A S\ y = Y <3 _ WH = (Ln. ’ Palo NORTH 20, 1908 VOL. LII—BUwtt. Grou. Soc. AM., i ae Ha itt J ts Ht te: * oy vr i ; NT. ' i, ae b M . { se VOL. 20, 1908, PL. 56 we ae oY Soy IL yi eS \ \s N\ MIDDLE ORDOVICIC (MIDDLE STONES RIVER-CHAZY) See WATT PRL NAAR AS H AMERICAN PALEOGEOGRAPHY By E. 0. ULRICH and SCALE 100 ° 101 200 300 400 500 600 STA em CHARLES SCHUCHERT, 1909 = (e'4 -) B i. NA th \H RNY | a RN , KA \ Ay at BL | WKN NAN \\ AANA NWT HTT SA <¥ ai N ts > yi gs i , \ ( J HINT NS r hi | a NN \\K Sil CALERA \ bie Nt x x as 3 2 = N BULL. GEOL. SOC. AM. . VOL. 20, 1908, PL. 57 ; uD [--) ¢ iD UH Sty Sit oth wif ert Sh wi wh \ NIN by 35 ———— ae 75 80 70 i 19 o J ~ / FS ee Ce —e ee Ut? cl \ ae ae ZA ee = fo ‘s A) Fo: DN h f nd §S (\ [2 Kl ay! ‘ y Cx ~ f (Re DK ( Na a Me me \ ISSN ~, NNN c il HIS MOINS SLA S SY ny, b NG NAS MOR SSN , SS N Nal | RRS S . RX i SW nl) ATT WQS SAS AN AWN : e x S H WX ee [yp NN LEH \ UN { we SONS > Qi QO yy ma > \ DS \ C " » \ \2 << N \ ¥ Cs % - e, eZ Spe Tg eV) Ne ~ Cw Ge : § IY GOS BZ (On if \ XN) NZ N ‘ R ROS \\ \S SW SN RS NSA SN SS SS \ Y ‘' NP si S NY ~ WW ¥ RY oF Jia RS SRS a A> “<4 XR Ss \\ iS N -& NSS SOBA L =) oN reiods WZ, Ns \Y OS Qo yy HERT, 1909 MIDDLE ORDOVICIC (LOWVILLE) BULL. GEOL. SOC. AM. NORTH AMERICAN PALEOGEOGRAPHY By E. 0. ULRICH and CHARLES SCHUC SCALE Awe =z VOL. 20, 1908, PL. 58 FL iL _s K mii 7 NAGE 4 V > Ns 4 et » y me RAS y ud, & Z oS PANY S od x Fae =) > iA ap Yer aS we WB We as fF) SSSS ”“ 2 S 3 Vj : WS NS _ SS WS AMERICAN PALEOGEOGRAPHY By E. 0 ULRICH and CHARLES SCHUCHERT. 1909 NORTH BULL. GEOL. SOC. AM. 1 70 MIDDLE ORDOVICIC (LOWEST TRENTON) . . ‘ ‘ . ° . > . TL / 2 Oe gis Yi d A, as = ] a 5 LY, a ) } A \ GY LY v XGLB i q | ale M \ S ’ Cp Ce we (Sees, Af Li Ss a ‘ Zs “5 : PBL we y* aah ee mee a . ‘A SS . eee Sea 7] SANTINI AL Pa Wo LA ‘ N ee Nasri ome (a7 NS SEI ai HTN | Pee. K a (aN R 2 Z> wl Mt N | SoS : AS ~Oy3y NS SNS 24 ac \ ers ORR Te SE . NEN < Sst ‘ I a OL LSE WR aie i" re QS ie PR TY a a ain EAS ee Ry 3: al a ~ « ~ \N a NSS as : , r \ : S Be Nse7 oe X p \ ASS Y XM) MU er 4 l % |e ARQ) INF APRS Z 2 4 Uy, ae g S ey eae V STR . AY L$} ly: YY VERE , CUS, OGY Z Ci Y 'G:G4 LZ ‘u 85 \ Pla Te, : ES 3 WY RES: BG A WA i PAE Y SS . S = = “ NWS WSN SN yy > oS WSS G rx & 75 80 ———————— See —— ZZ = ss ZZ rs ZZ A WT a TZ Z7 Be saee ra Le asa a SZ ZZ a Wa ras ZZ a = SZ = ras = ee ee = Tc, I AS, LE LEY ELLY LP 4 EF, i ‘a x rt L— ZZ >< = = = ZS ° an @ oll 00 Hd HH OX] oY B w 3 ) s Ry 1) {Nl IN N | { vy gy Win A. L [) y ‘ag =p ~ = 0 a SS J Rs 2) i SS > Xi Le NS] FS 9 SS gq f UI > é 7 j TAN = M y 4 al {] re, as A : = x ’ : (> c “ 4) <4 & g SEA seats S NS ‘ L. SOC. AM. a i \ KK AN x ‘ a m Yr ad LS ZS S Zs a a Fz ZS 77 ra ray To aN a = =. p S\ Cong el s So rs ZS ie er ae > aw = SO x Zz Nw ag = Y = ~. ere a Hi We if i i tt Hi lf | My, Maes uh L UL VSS ~s 5% v R ZS Lo y, ZN wy gh “Gs, = Se! C\ \ va y, "OXY ae G®, Y Opes 0 4 & As y, SLA gi (\ A =a, ate Xi \ NX y aN —Ws a 0 Wz ot Cy F mae || s ) ‘ IO TR ek AC cae 4g | a i ) a BD Sani Ph 3 Ne, oO (iyo wees Ene a ‘iy ar: oe Sey hp Hs \ j . G = (| Wy. ANN ” | A Ey ~, j i f RS Ls ; Dy < , NAN ° NTN N M4 rN N NY y yy q ; 3 DK Nal : Lx } , / i i Apne hes at me hs / e Ye alll bd XY b 46 5 lp, AN xq z ‘er Kt \ > BIN S SS WSs RY e Z WY x ——— vs 3 l 3 lll wu We. 3 ND) VE ‘ nian . ee es at we ! k = af io. ats sy zs e rs mi ak 5 ra) ; ; . ae | eee oto art ere VOL. 20, 1908, PL. 62 BULL. GEOL. SOC. AM. Vy ise 5s UK s 3 | P Yy Bs. 7/7 —— (| ‘ \ : a . : WS \ EUS BES \ —— v¢ " 5 Fa \ =. \ \ \e yy 7b KT - q sO 13 e x) ae \N P LSS Ss S SSS = SS a = < 5 80 85 oe Saas = ZX = 7 — N NS yt b AS ; N\ s NN: EWI. oo NORTH AMERICAN PALEOGEOGRAPHY By E. O. ULRICH and CHARLES SCHUCHERT, 190 CINCINNATIC (LATE RICHMOND) ae z co = “iy s 7 f / Yy Lp RS ZG OY ‘ \Yy iG YY s —_ i is > y GY 5 ) UY ° 2 | iM) a SOG Y ge I SY A Yi : , E LD INE G Yy a 3] an Ky !_ 7 = \y- 2G are 3 MN ] F ; v Y Ky - SS oy \¢ s 7 \ . Spek i} ’® > _— } WS y \ - AA S xy 4 oa A oe <\ bd sy I" ly ») ‘ = --} \ we : V4 ¢ wy, ; f = H F os ‘ S . WA FAO ie ZA hy ay = a ay a a V7 et A lad iy p )¢ xy ; ass ON = 5 rio i \ 5 a Nae 2 gt = : ce : *s Cpa fi DK | Z y b — h tine R) \ S Vs \. ) cally Al (se) oOo Ff. = a t nwo ~ go (oe) jo) [op) a & N s fio SJ & OL Eee % ! HL See IS = eT i = Z = ZZ = = = Z I x — — —— SS TINY ii ) ro) \ ; . aN 4 \ QQ RG \ a ~ rs eee “aN 2 eth | EE ) Y of : IN B Ee ets : 9 3 aie ee cs NN f WES ~ AN SUL: M. VOL. 20, 1908, PL. 64 7 15 80 85 85. 20 75 65 | ——— SS | ee ae a = 7 eee aS | SSS ny 0 SS | i ze = ane —————— ae te | . eee = 2 > ——————————— eS AI : an = ———— ae My = bs, VS a \\ 5 —— er ———————— Yco S Ze, \\ A) Epparf, : A & ZG NS \ a EN SS SEM’ [Ss i - oy 4 XS (X L = & Uy . 55 Ks vr D| ARES ‘NS ee e iS , \ 3g : N NY ue oh (U, ‘eS Ro \ Oo . — PLL SA AOL ot \\ \ 7 \ “hs Fa) »\ . = sy XN a4 Db. W Y \ " X Sr o ‘ . V. SS S NW ES Neat ae SW xt = SS ‘tal mH) RX ye . N | NK . Ae LA GSS = Tm: = : Cy I ins fs 4 4 i y EOS , 1% V0 WY g \- \ \ B \ \ \ y ae AS \ ny> VY SS S 4, y IOS S ale SS SAY Sy SS y rn pra ': ) a5 YS AQ 5 SS SS Nig SS N S IWW\ \S \ \) OO Sn MENSA > x a . ft A] ! \ \ PSS OS SSSA N f SS S fi Y ~ e 7 / Y = (j fo \ o Noe ~ oN of None (oa No ig Wr us es MH rH ~~ a si D aN 9 p> NS Z Ss rN . x : = ee — OO » DF S $f SY ¥. 2x Xe S (4 Bu ‘ A Jb cf try © [eta a rhe’ S I OG KG &% e\ 2) 5 NULLEUN bE SX co ae 5 = 8 4 = Web g —— = be VOL. 20, 1908, PL. 66 inal | TALL rote ieee UU ete aa rh “alls N a! 8 30 76 70 MIDDLE SILURIC (ROCHESTER-OSGOOD) y) ° | a 2 = \ r & > = ALAS Bx “ 54° y { oe Sa (GG S U A 4 S . y . yy 25 aA Zs +. : ) 6 a Jt (irre No i x i DK TT he SS Sa, —_— oo ve ‘4 LS i Nt = TA 4 | ° WIE SS SS ia S a Ee a4 w = 12) =) = oO n 77) w —_) 4 < = >) > ao o Wy u . SS eh Wo Nak A {s a N Kl hi SOR iS EAN 3 g NORTH AMERICAN PALEOGEOGRAPHY BULL. GEOL. SOC. AM. as BULL. GEOL. SOC. AM. © ‘ VOL. 20, 1908, PL. 67 eS me BP | date tS Se —— |] - Zi |p = X i‘ = Sa a Wedumestizse ied HM af WN INNS Q : , | 7 NORTH AMERICAN WN CH ae PALEOGEOGRAPHY Ly Lge io— | | l EN, CAT CHI ip } Lari ls ={10) A x % 4 4 hay SCALE , 4 \ u 01 300. 600 STATUTEMILES 4 4 dy Wy | 46's An ne no 106 MIDDLE SILURIC (LOUISVILLE) SN ROI mse Pa be A : Pie | : we aA A ae Ung ba) LL’ ‘ i 7 ' e 2 er ts a 5 x ~ ns *. n - t « > « i » a * . a + . VOL. 20, 1908, PL. 68 BULL. GEOL. SOC. AM. By w = 12) 7 By CHARLES SCHU MIDDLE SILURIC (GUELPH) . be ’ oo) q ¢ i te 29 7 ‘= if PD dary ion a vctidedine » “~" a > Limgh9 ‘ ’ 0% 7 ~ a : dl a” > UY e w 7 ~ “ 5 : Se a by 4 abe sas, a ' e ey | * rv - ~ = - — i ~ « r 4 td elie Deena ay ot it Seid Lk - , SAEAGi Lee =i 1 SLA Me ao Neen 4D c/ . ¢ x LiL 4) ,) rd TAS y [¥ - qs eV K = 75 80 ‘ 2 ; 80 = Sa 7 ee = Po ZS lg ESS a sad ilo A [Se . AM. 70 Le iS BULL. GEOL. SOC z=, Ze \ Ae) 4 ane MASS ALLEN ie / / oO ——————— 75 8 85 85 EX) —— —. — oy oe ° RS X ZF SAS \ ~ = Ze 1, > aH = = Pes lo 0 CSS ne = 0 95 3B a im > ‘ S Tl es P y 2 AI SN I <— f} d LVR aN Te x Di 3 : Be. S : Y, NNO [ee x Oo ZINC (DS (7p) . XA va -s- ZZ ZS ZZ aT SZ rs = = Nf fp % fan a, 4g OG \( ‘ Wm IN pp i Ki ee d Pye sy ie a | a ) aks cone — a a a ee LET EDT ET (IT (I [EI FD I PN —. ; SZ g =; a EEA 4 LA EEE SAS ES N =406e% eee == \ TF ES AE Z——2 = ol Z———7 ——— OT Z= i WS f ( aed & aS B's \ LS 2 \ S NN B o 3 ec \ : en . OL aN Z = \ i SOR | , 4 ’ . . 2 * + . . A * 2, - + . } i F i ' — % ) 4 e a pe 1 | iM —_ - bo hal yp | , ; = ’ hr ’ % = - i ht _- i ~m =i Qa 1 ~ fo o ff [o) (op) - eS NF = Ho & SESS TSS SSS N SSS SSS SSS SASS SS SSS ° RSS SOS SS a SSS SS =>) SSS NSS N S35} 5 SS} Ss] qi ° n L ry 2 aS 2 a 5 ° 5 2 |] {2 3 = 4 TH AMERIC LEOGEOGRAP d . AM. 0 75 80 ———e >= = S x Za . Pi : . ‘ ‘ P . ft . 4 j | ; - * > ° ° q 4 ae 2 mt arate, x == —- iA 2, = ‘eres ernae = =] of Pare ; NN has ams’ 4 S 7 wAYo GN) vO <) aN ge, \ fe NNR RET NORTH AMERICA PALEOGEOGRAPHY ee a R rr) ‘s 5 4 2 \ a . (=. Le p GO \ op = OY \ -, c; — SY ee Es L~ SD = ——. & < 2 ? \ eH eS an ») a a fo —~r 1 Se 7 a ea = ia] ft _ a ( OX > aRimen Soe = A Me \ as as : igh a ee S i ) oo iV Av Wavanaay - ) ~ “att peanaddes aa ETH feet PSN ELT Bia ten tls | aa ES N \ NH bt ie uff Y : ti I pe 5 NTN U4 S Dad AY PK yy NI) Nd N IP e \ } ( N ys. & NS . \ \ | +S Wy BENING. a Ds? WW o > WIS IA SY f} CP. S ¥ Q\\ a ies J ty ~ Se pas 1 IW 6 | \ oh SOK J . \ sXos at \ \ Pe (72) a (@) wt, © jo i IN y. an 2 . \ A bene Messen S : —7 BULL. GEOL. SOC. G5 = 70 75 0 ssa — =a ——— ee ES = <= \ ar S, > SS aS Ps a TT LILI 7) Ss = ee Fe aI LT LT 4: (ss) a SS SS) . SS eS. a OSs a = eee FSG <= ( ee ee eee —. I ph lh ay a aT AT A ae a Ujjj,. at EEE as - Da, a, ! : LATS ts eee SN ERS ; SAY Horas \ 1B) me { cz | He \ cy) ° LOWER DEVONIC (DECEWVILLE) ; : ’ J : : : : a Lat 3 J j ‘ ‘ ” ; re : j | 4 a \ ‘ sui i} + af / a a ce f—} Mee SEl 5 fell a | / LAY, Les was a { 4 bo AQ Sa20 a rn me Ne 77 ZA (4 LAdiwh> 74 a yyy H | \\ Paneth 1 sa sO Wessilh alt .a S - — — = ete = ae See tsanr —— 7 / - i fan Ls . 5 SS y iat A iG A va S . : Soy “ An AF ; eS wy 7, v \ SN : i AN : ‘a o {| \ OU CP | S = Wa A INN | o5 ON = ea Ti z _.is 4 Ve 4 Z| < OK +2 = 4\ = DBS Rae: eoaAee BHT TIP anna PALS Ue jai: il PET Tt Hal lead Mjas alll , Hace Banned y : Hi f Sy ph ineye Hi N | == Zo Son ZI a ae om pi] ne —, =D. SS ——= Sa eH nT : Se } z ‘ IES x = NORTH AMERICAN ° PALEOGEOGRAPHY < NG Ge \ IN \ 3 SO \ | ee hl ee FT . . a. . - ’ . s “+ Sy 25 * ro - VOL. 20, 1908, PL. 76 PLD L/G £/ ‘ Qo? ak A \ tPF r= \> NS o> \ WZ G o XS J Ax 2 ; D S a) g Sd S 4 ’ ~ _ ; a” \ Xo, J Ox 4 14 r) D S) Ve [AZ 44 A MA oH 5c J ‘2 2 L y 9 A x oe $ Wty \p v; ZN \( \ ——— 1 was aa f> q ra rv, ee ‘\ an (7 \ = Ley AN Dp Ne 4 e — om SSS 13 i Y 7 Tt é Hl ~_ 4 - = U/ WN wT paalld ey TTanaKe reall A Pett || Iq 85 MIDDLE DEVONIC (LATE HAMILTON) iol 2S Bh Ec war wes it i) sa Sy LOL] ee pa aN : f agr a NIN KC | by N CNN a | ¥ 2 4 S Ha f ll as 3 Ze Me (2,5) So I> A\ q a fF “Vv 7 = B7 ( bd a \ d S) ? - \B~a } vay ti 5 Se SS) h te i \ i i i I Meta eA NORTH AMERICAN PALEOGEOGRAPHY 2 By CHARLES SCHUCHERT, 1909 BULL. GEOL. SOC. AM. 1 My 1\ N a ti (nee, pra i} N 8 rai % Xi H h ul t: a 1 4 - , t 7 VOL. 20, 1908, PL. 77 iy : | | | x qe il yy / ) ban | Hf Yi hil Al elt gba ual Roti iy cant OES ' i AR > a N ch So ge Ke" SS = S' p Ie es . 8 lib ~ . .. is By ¢| QB ra ZN SANS : P ” : WK SSO r z Hy = 7 = R Sy Al 4 4 2 i ‘ . sb } , PO, aN SE SNE NN — we YS a Ne ‘S y p . NY] sh NTT LENT YY ard Pb SSS NY ISSSSSSS ae SS 4 : ans ane: é 5 Nis Wan ; hos "i th a fie eS + SF SS Ds f/ P a> \S XS TKS ¥, ne “DN Ne / Ca N ) LNG Res iii 5 => \ i MS \ WNEUDE Zan 3 NORTH AMERICAN PALEOGEOGRAPHY ey By CHARLES SCHUCHERT, 1909 BULL. GEOL. SOC. AM. UPPER DEVONIC (ITHACA-CHEMUNG) a3 Ae / 4 ' : J 7 iy i) iS bc waa) As > UY NE g : N LA N | (lite SEL Wy ial X \ Hi oy 7 y, i a O ra OO ——— 3 — ‘Bp ————— Zz ar _——— a ol V i ra I @ le 7 AB Sil £2 S | Gee y a PY é fo) y > | E S$ ts py y. YJ Q ASE Oe I Wee CZ WL) (I hAG EL WW AA FOO BR BARK ON ES OIE AT 28 ( s = eS TO Das H eecipill Cane oH Ze Ss tase HEPES ear py sill Ha yavem, ve CELL PL aKggy nN . i) SHH TTT EEN ELE re SRRRHATT Gt ( 4 met I 2 ; HO ANT oA i I | SANNA TN et OY) RL fren = +] 7G dj iJ diame Cot Re OSI OPER FE 7 R99 EEE LOSSES ae calle yj 5 SSB t ( ~ SESS ; SIRES SS SS o SBSASASSAI SSS | A SS = NLT \N RSS 5 == MQ A ~ i N N\ IANS: WN 5 WSS N R ANS NS g Fy r < SSX 5 Zz 7X = a a Ms rm Wi 7Z\ —_ 74 Se [7 a ¥ N bd K) BS i NI } NY L H Dis ml Q > NORTH AMERICA PALEOGEOGRAPHY RO ° iN ail INiitage a | INGUIN a : LV—BULL. Grou. Soc. AM., Vou. 20, 1908 . GEOL. SOC. AM. 10 75 = - z oS ——— ee CNG, 4 7 === Pa] ra —— lil 4 —— \ i) Hac if : Cae U } g) i] AY LX Gog Wy LD Yi ty 2 = d\ ea (oan f LQ f « i 16 eerie WA (Sas rd Ti Ds J AU OT STE il iva rH fa vai 7) ei) ———= | hy ry ALES ‘i RETE K At AA \\; VANS 4 S io memeniee y ° ° Nw Oo —_ wo ie) CO C) ao BULL. GEOL. SOC. AM. f 65_ 10 75 BO a CL L \— SSS ee | ee BSS SSS, {\ ; J ( < ‘las AVES ‘ Z A = “J AS; Z i> Y = | old x AS Xb > we Sees = © Gs LE , < ‘ i { ne — A MR er uct NI dhiiisil ie as g Yy Ds) APT), le 2-2 Hi SN INN a is ANE TH so a ARAN Ht esore ES Rete Sa tl y STRAY aaa ) RK Sl, 7 1g ' AN r NI 4 P4sebs eerie j | il Fo] ait — a cu hie AY : y SEA isan . a PEE i G a She ae 80 —= = =\ = <> ZS Z —— ZZ ee Z—SZ ZS ras oa : 2 --_ 0 s = le — 2 \> Che ve ete Cc. AM. 70 - = = a — ee = = Jo ie : ~ . aD — q = ¢ l- ? N | : 7 OSL ARS | : It AS ? = 7 : = ~~ e} 7) ri zs rs} we 4 SI} =) oa) 1908, PL Ss N WAKA ey ES bs “5 LEN YY ig j YY \ 1 MY Y ASX WY VN SP q aa Miia (ees HZ f SOG \ p oR) er ae 4 A > ee ng air \ we i Rp A Ne NG ime Dy lia SY ee SS eau vw A HRS : \ LN | | ea f i oe NS : Sey | TH cH ine a ail TRS va WS) = > Naga 4 ' RASA 3 sal OATES K k ie N i AMIN ASSSRRN S =| ie NA Mest ANS =. © L\ Ny al de = a) 14a) | x a NORTH AMERICA SS RA \ WG a KW“ 3 B g Z a = : lee \\ SERA WG \ \S \ VX WN IN & BULL. GEOL. SOC. AM. “ es 1) BI SA —— SSS ; < Aw ri S { 5A ; em oo —y a bape ‘7 =" F = J ‘ Rs = Wy = Hi a Bilih XS a 7 S A By = - ond : sl 4 * : a 2 , () A a\n — \ tC (4 | 3 =" nr Gj em von SS) d = _.w, X | f ; rh A — | A by 5 AS = 7 1 = as EO . KS ss Pe bas Sr “ae se . -_ ” —_ s =, £7 s s rv fy = = Bi \e i. “NY Ja 4 BR. 4 a S _ s (-—T% — Zi a r — a — = w = = f ik > = ~) aa >) aaj S S he | a < jp fe Y < 2 ds { = (1 ; ZG, Y ——— yy Y o re) ® 2 S a es Oo > AT a i SRUGH BR OOLUAET TP = ‘ | ay Lp = WS ‘ LAN TS YTS SANT TT HALT] eo SS (NN aan B!LITN IN INU eso Ud bal (AA (' > V7 e Mt ( ak ae > Te, yr. Ths Ss NINN | LATS mony nS, ered Vedi EN LL. { A US Sh LET NY ee i \ . YI = z |e 4 ’ | ; : : - . ' | . Hi \ x WII) > eS =) i ar aw: — a Ta S75) 2] = 7] att =, ZX Ay ah we rai om we 8 Wax 4 <- VOL. 20, 1908, PL. 86 5 ; a HEC 85 80 75 = = S, ek S\ i? == SSS ew) es >. = = . a vo Me tine A Nee eta opt. = rer ." J ali * 4 cr = 1 i pal s i ‘ - » oY z ° \ Py f = ——I ° & 6 4 — Ve A b Lae 2 GProp NS 5 } Vs _ =) (t .: Q D es yy ZA i ~~ Os/ = & eae | SSS PoSeesy =) => \ SESS \ LYSE SS SS Se \ \ SSSeh 5 = 1 CS rT Ae SS D SSS (2p) ONC nS Se ee A SS = eH rea eS? | tga fd NS < Bob. i f CY c N © NAIL i Hy aa xan Vy Pa 1S = : KN AK S : KOPSS z 9) QO © : x N Mang SG LVI—BULL. GEOL. Soc. AM., VoL. 20, 1908 Son o . 2 v 2? a 4, SANT fe Xi oO b ae S) o> y, Ss Ee. ox els pA Se pe \ i 4 Se J? 7 E/ 7» S Q ae Su - 3 wes 4 ize A { iN \ — Y No 95 8 —_S x — an en Boaaanw LS aN ——— a N Cc. . 75 D> c a ao we ~ Fe I g fee) co) | / ce>) J — y S | i Oo ih Hy \\{ 102" > Hes, s a f oy LR) Lee A Vv Veep yy Xs Ls . > ; \ (IB ke Xe oS \ wx YA ay Sy af 4 ee : iN ‘ P << of . \io 1 AJ oA W\ oo) >> Xj e \ B fo oS }) > U eA oy Wy 4 J U \ yg c I a 6 ( q \ " e' = , \ ‘\ ) t De < Zl Ee BOS \p Crd re = aX $ Be, Ale be SJ an i \ p (\ ef af et nd he SS 15 80 TBS ree aS Seer o —\ SSO aa ae a OT, LT LS LF LD EF LD ee Nf a oe nn mf ma a S ae y) IND aS a: ——— sO § rgb “ + eid oud 8 $/ y, i NTA N Dad int \ HY \ | | \ BO Se NORTH AMERICAN PALEOGEOGRAPHY - SOC. AM. ; 70 io BULL. | 65 co 3 SAK < N 5 \ SS El] Wie < CON \ : . SS S = \S Wane oe 7 A =| | 4 } Z MLSS = 8 } THR 67 eo, g ‘y | ——— ie | ' a i, Tes > a My We ee ——————— Yes ie ae , i) r Q Mt =, oa as —] —, Sik I f ; es Be oes * bt Tac fiver We $ Deelenee b ' toa, a ali o. SHlIIHII _———— es es 5 Se SS re) | / ) me S S | 3 iS V | | O | I We , > | RIVES, | : | QV x Y Hr : ey , ° 3 _-— \S ‘is z \ S si = i J : yy : : att A 3 CT, Sree SS 0 < ; ~ & \\ 2S" S64 Z | f Na > ‘ : EN : S— | : a= Z 5 c\ Bik aang VEY < AN } f p LK pas BA S&S Se ft ae oh A] tl eg os iY S Diane. De alt ane S ( : S oe Y | i A, {\ amen he at ( ut a ’ ltl | i Vai: & & “ 4 pest he : wet NA RE urs ca My t \ f i | = —— i ————————F a eT = LE | eT. TT eee a EE) | Se oe Sarees a = © a SSS Se SE, ON ee SS Pt —=— | ————— _—— _————— iy ge CB Sp Yj Yj OS Vy , Y- Gare (| Pi Y, CY GY Be fy yelp, CG ‘ p oe y Ox ] C| i ean fh oO L 5 2 Bie all Ly I fe WE 2 (ee Nt kee E/ Mate] bAhte Se aC \ ek 7 ==\(. rv) r °l9 Ee. “HH siN Bin z We Gena fe) \ pa | (e) if o 2 b S= i SS) ‘ : NS , a) Q ( \ 0 a: S — to x as {\ Hh TO Ds aN Nt Se ases) | og eeRLOT igs peattle SAAT po ce : | YIN I 3 : casi eo} BLESS Sh D 0G at eS iL \ | H A ve : NW fs W7 si x >} ost G AN | i i) a %, = = ( | ; Nak , RST gs SPS Pe Dx] ill Ny . < a . \ ~ 3 O CE < = fe} Wl F < —! " 75 BULL. GEOL. SOC. AM oo Oa BO_ ates 80 75 EE S_ Sa se Ree ew SS SUES = SS SSE XS BE} ay 5S YG = (ys * ¢ A Zp “ya [Ye 7 7 — 1S — a Ts CS ES ES EIS AT SSS oS aS ——l— 4 =m A XB CA Poorer ra NG OC argneeme. <4, dass 2.) PG D AS =e \ "3 h eo ee * . ‘ : . j ‘ t ' ' . ® . ' i tr 5 ‘a 7 ‘ a F a he a . — ZS Za SL ae 7 i AR PI SASS elt Ma S a 1° ° a —rS (arty Yj \¢ i =e ass pa LA UY yh) pean gs [J Soe 20) LPP | SK ® 7 ee = Ma Ie oR 7) na ffim:.. >) Pe | Nr HUTA =r A es Kl Mi i BOP f 4g Y; LOMA $ Ly, / WS 20 ver y y i j i —Y K, Xp Ha aca(l itt bed Y Lf y A KA 7 Na 4 Yyyen Ne ns ty | 20624} { ‘, ui YUMA i {7 Az q we id (2 Yllbdty fal NORTH A ICAN N SS c = — et ~ — i SS ee SS Be A ee CD OTT ae SH = of ——_—— 7? —— 159 b I | Wray ; Se) = ASK! a} ——— 4 “ u ow. 02 n Zo = ° r7 ° og <. NG 5 1 ° A « St = # Fa), =. IE ee wp GN) WU , cl WG-5 ON XY Sus tH oe A, Do ane V4 ~ w entity oO &, Sa, TR vz ee, bm BK W~ IES (A z awe \ X-, g Zo fe ae SZ EET 1 cs a= Z Zs ay Zz ras SZ = 2S Z ZS = = x LT SA SZ = ras ra = 7 SS LET LIES (ALOT ET hee “a By Ny Ley * Sax y >, ‘4 <( y, l) S PR * . 1 aR wy BD os Y x) Ls F Y. Y ay? ie , 7 j N = AN Y % Ya iN Y D AK * G 60 »» S ORTH AMERICAN LEOGEOGRAPHY NH OE d = 7 = x > \ ™ iY hy (\ a —j/— yore o———~J oa / EX LEEEET LET EI 5 7 —__7—_ 7-4 ET ES LS i, SZ \> = ZS J Ja es = ZS —— Sf ZS SZ ZS NR fon) af (ob, ice) So a - ss N =i oO > i} r (] [-] en ( o—s J wu (C-) Vj od ov 2 ¥ wA ' | N i a 2) r z ie ° al nS Ws 5K A ee eo af Y Q f : = x 2 \ oO i Cy r\ a) ee K% ae eas | Y 3 aN sued aa Je e Paar aN ly eS SX Sa i Fay he Ny ‘oY UY Sp WY ee \; LZ Oe ; s scoaeae —? = oS 4 ee e = ZS A ST ES ET SS SS ST A SE SE AS wi) SS ry LIT II DLT SF | I 0) TT \ LET 2 7 LES LTD | EEE LET Lhe LT Lf TS A A A SY A Y _ ET I LT FI) 2 S SSF SS SS FE Pa ————— ae ay IS LY yy Wo L Come RS BS LS A Jb WZ RM A ‘is lapis = ie . 4 ; . : ‘ ie ~ - - * - - me 4 - ‘ ‘ ; s 4 . ‘ . Pas P | “2 ; ve i | a. P Ps # : N ST AMULIWetes Oana : Peer: 0} \ NG ff Alen \ ANANNRNNANANRS L\, q S : NAS OG ER AWS . a RA, SOUS RAR = AUSRRRNS SUS ZR 2S co y (1 mS é Ze Vk Y C RS) ZY N7 4 Yj Y So Z' " NS Vs ‘Ga fs i x wD N = e€ ABN : 3 | s AEE SA eat HHH GS ante ; SET } = J ves wane: Re #71 2B ZS = ZZ a—\ ZZ 2 a Zs ZZ 2 a x ZZ ZZ =f = x f=} Zs ZZ 7 NE LEED IL LI, LID EEG LEY (EF SEF Fa OT A LT LOT —— &, XK \ x f/ 0 A Y ‘¢ y 80 ES SS 2 we L. Grou. Soc. AmM., Vou. 20, 1908 a B 5 ZD AY TREY, Y YY Z ene Yj, Mitt YY GY LG iy y WAS Y 7, A7 Wiles, & j \ ( : Y, 6; 5 UY Co T Gi 1G GUY . G ¢ 4 ‘“ A ; % CT / hf o x f ‘> SAS

) es N ell) ° Sh {I f } (e) ~ > LAY oy i} 5 y Wy, 4 WY YA Wy = A\ PY PAY al 2 HY MM te Ne BAVA HS chegnene Mg aa WY old L--}e- 1] (j Ay en L ott 1 HHH 2 “AHH i sai Ay TUT ee aa SIN PS 7 4 aig Pa ' R iS ' \ a rYU-& oe? pies ay ee ==> 9/4 = Ka ones D t £ > x = ~ 2 Lo LAY ~ 4°: zo =e SNL Io m a Ly a, se fe 3 SS E a é Sr ' Ze = Cy iS NY a, 2 Ng S\ NAANAN NARNARRA RRNA gs KANO SA Ki 2D RbeZ fl oO H im ) = 5 N a ASS a a 5 w CJ Alan a a en a res ee Li > % - ® < 2 - wee Jesozoic. Hat VAY ETT SIE a oe Os Pn ee es : Bae ee re ae ee ee a eee a ere PL. 101 PAGER 50h VOL. 20, 1908, Fogenic 50% 30% Cretacic 20h aua20jslajq4| 3Ua20I/f SN avaroip/ dj 28 ua roi) 4aMmo7 = 2ua20bI(Q 2107 x auazobijg hjAoz| SS aua20z 3107 SS auaa0z hoz te wIafas) dsdlo7 Terttary ar Neozoic aiWos07) © = a442/d| OT pIDIGOIN 2S uoluag vloyog ojysoM 2427 DiYysoy, F/OZ bing s2/sapasy 25h; ALU AL ao7 2/SSOINP{S2{O7 DssBinp LOU Fy] | * Jurassic | Comanchic 25% 25% R57. “hy 2/ss Bsn (CNG TONZ ON/EG "7 J/ssbsne N2issalys nd 25% W 2issas4 Neozoic, Aatio 2. Mesozore. Mati 6. Estimared ime SMM years\ Neozetc, Katie &. Triassic Perinic Gn / IiISSB/AL N eiudad WH aes rinjan Triassic \Jurassic \Comanchic| Cre aie "7 W/W ad Ub/INOSSIy) 2407 lah —+—+ Uopsnossipy Ao lA 9/[ ASHQY 3427 affIASLay hj4oz 4alSalj) a/o7 Yaisay9 hjsoz messeel\ Fenn sylvanic Th pian \Pennsylvanian Fe s/no7 1UIDS iz ID, Uabsadg 15. fp Mbossb/ Jamo7 YnApoay oh NSSISSIPDIC vosbuyjing ual Ula |~ Uoipsojposg Bunwayy 207, olf Dinkleleld S |taltels” ~ woos) Uor/(oH] A107, - | beep wou aj//AM 02. fjostoag puDj1o2g May SM[HOP[ 2M 07, 10h Faleozoic. Ratio ~ Fstimared time 10500000 years. S//UTIC 10h Devonic Mh . riela| | lol? Het Alm je rivcla S//urian\De yonian Missi ssi ] PUOWHOIY 8107 Puowy >] JaMo7 EVIE EA Cincin nati yA Tapy [ear aro7 DIM AAD. Uoflaly a{o7 Yojuaay Isamo7 lon {| Ratio /2 Estimated time /8000000 years. 23% a/[IAMOT Cambrie or Ordovicic li FA 67 - | al (Prlelslelnia rlela Jalag 1uIDS Ordovician Umojunuiyaag o/pouns | Ih n 2171820| 7 LEO: 5h Paleozo/c. N Wpooy W IP bY 7 2p b2y Facile Acadic |Ozarkic ,\Canadic w Eras|Eopaleozoic. Katod Estimated time 0000 years Ne New Peri BULL. GEOL. SOC, AM. Ordinates N) 2/4000] c) Cambrian 20% Wr/voob] 7 yUOoo], ~ ~ & > Cy 4 ~ ‘sayp/o4Dnbs 000°000/=2JDUIPIC) Yon CURVES SHOWING THE AMOUNT OF SUBMERGENCES AND EMERGENCES IN TIME AND SPACE a ES an Mii BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 20, PP. 607-749, PLS. 102-111 FEBRUARY 5, 1910 PROCEEDINGS OF THE TWENTY-FIRST ANNUAL MEETING, HELD AT BALTIMORE, MARYLAND, DECEMBER 29, 30. AND 31, 1908 EpmunpD Oris Hovey, Secretary CONTENTS Page See oiteOmeMUesOay, DeCEMDER 29)... cc's & ais 6 sieve-oge obec meine eee dae 609 Pec wOlimOle LNCy COMME ie io. ia stevleals cccrsi s°svel di «soso 018, o(eredslicn efereiaunee Shue eae 609 SECLELAY SHC DOLE cia ui Ae, Srare cris ood oe ala Hane cea earl mae eee 609 MRE ASTICET YS: LODO cre si Niald: Ske cuatetla ciehayaie ov cleo Susie ar aiatalane claret ta at Mn a eet 612 Fe MEO TAS HIG WOT bai wsetonetacap tena: casted: slepessrey eas mies a alist atin “ay ates tot Sahay ater teats aroma ae 614 HE VISTI ED ONE a Sees aba emene: aravon tase teeta Gaave ie aoe ie oe ea Secale Ee 615 Peel la OM COLS s.lencens p-5 kits ate) ols ie siies sie ole & ala a ieisle. ocd a aleiehee @isnsepel ate 616 eTReSie WTAPTI ERC) THEN LOWES ees. a'0y Sie cs tal ete ts ica si aw eels arareh av ealiele, ay ecaile elena, Ao lorcceneeees & 616 Memoir of Homer T. Fuller (with bibliography) ; by Edmund Otis LReRRNKCSV RE Ice AN SKS, Sere ona) oitetet (ast aaata eye ses vab cuter cite adey'aay Seah Sette eam ice cee eS 617 Memoir of William S. Yeates; by George P. Merrill.................. 618 Some distinctions between marine and terrestrial conglomerates [ab- SBE TCR, POSED ESATROL aoe) Sere ses wed ofabanns ota) Saye: ast hoe 6 cued Store 620 Report of Committee on Geologic Nomenclature.................... 620 Evidence of former connection between the eastern and western coal fields across central Kentucky [abstract] ; by Arthur M. Miller .... 621 Landslide accompanied by buckling, and its relation to local anticlinal HOGER OT OAT at Eu. VAM MOTI Aa, calls, sitevbile ew a lcvere' eid sod aie ieisied eis exe wie ue 625 Mount Pelé of Martinique and the Soufriére of Saint Vincent in May and June, 1908 [abstract] ; by Edmund Otis Hovey................. 632 Multiple glaciation in New York [abstract] ; by H. L. Fairchild ...... 632 Seino eanesday, December BOs 2.0 sie < kcd cle cise cade cae see aecieiee 633 Glacial waters west and south of the Adirondacks [abstract]; by H. L. ap REED UI iad 4)) 2) 4715) c PMR Oe Se eRe a A Balai cite alrattasteray Stel wh gviel Lae aie ah Rieck ws 633 Correlation of the Hudsonian and the Ontarian glacier lobes [ab- SUED CLE) AS Onyaan S aml Gry! S) Ti ec) ail oS a ede eae es Se a 634 Pleistocene geology of the southwestern slope of the Adirondacks [ab- Speetlece by VValliia rin SMe re yeiulas o acistlasiaslateeceteliielelesslasicnedes 635 Weathering and erosion as time measures [abstract]; by Frank Lev- IBC leeches) aia pilots cate leis; bi otid whom Rees cual egabnds Seta sxchay ctehaiaviater suetecg, of ar ciet’sjle'railel’slar, sh s!'s 638 Glacial phenomena of southeastern Wisconsin [abstract]; by William SOP NLT asters ter sii in au asain, cfcusrcheWeametep ate teers lens ora eid eel gisele aie x etacienen 638 LIX—BULL. GEOL. Soc. AM., VOL. 20, 1908 (607) 608 PROCEEDINGS Or THE BALTIMORE MEETING Page Criteria for discrimination of the age of glacial drift sheets as modi- fied by topographic situation and drainage relations [abstract] ; by Wallin SAT Gem ys ois cccts a ee slosh e Soereee exc teasueneteto tee e eure rele ee 638 Lake Ojibwa, last of the great glacial lakes [abstract]; by A. ie COleMAM iis bn oo os oo wine aie ko Wiens, ceo woe wale) eee Caen eke 639 Glacial erosion on Kelleys island, Ohio; by Frank Carney............ 640 Chalk formations of northeast Texas [abstract]; by C. H. Gordon..... 645 Results of a recent investigation of the Coastal Plain formations in the area between Massachusetts and North Carolina [abstract]; by Wil- liam Bullock Clark... 00.0 ccc bic ces ae 8 eee es sce «oe 646 Geologic relations of the Cretaceous floras of Virginia and North Caro- lina [abstract] ; by Edward W. Berry............02. 008-5 eee 655 Report of Committee on earthquake and volcanic observations....... 659 Use of ‘“‘ophitic’” and related terms in petrography ; by A. N. Winchell. 661 Chemical composition-as a criterion in identifying metamorphosed sedi- ments [abstract]; by Edson S. Bastin..........2....05 see 667 Tertiary drainage problems of eastern North America [abstract] ; by Amadeus W. Grabat... 0.2205. 2 oe Ses se ge cre ere een ee 668 Drainage evolution in central New York [abstract]; by H. L. Fair- CHING), 6005 Oe Sicisid Ted ee e's Sb Sa ee ae Se Oise 668 Nantucket shorelines, IV [abstract]; by F. P. Gulliver............... 670 Iron ores of Maryland [abstract]; by Joseph T. Singewald, Jr....... 671 Quartz as a geologic thermometer [abstract]; by Fred E. Wright and BS. UA PSOM osc ess baie Siete wines Seo stews Sara Solece sera er 671 Session of Thursday, December 31... ..... 5.02 ed0ce es coe see ne een 672 Occurrence of the Magothy formation on the Atlantic islands [ab- stract]; by Arthur Barneveld Bibbins......:..2...4..05eeee eee 672 Erosion intervals in the Tertiary of North Carolina and Virginia; by Benjamin Ib. Millers o..0..0 sc. 5.05 seb eee nie oo ee eee 673 Character and structural relations of the limestones of the Piedmont in Maryland and Virginia [abstract]; by Edward B. Mathews and Das SE GASCY 5 asd co eens lane eters aire oe cere deulenetetie ee aie sere eee ese 678 Recurrence of the Tropidoleptus fauna in the Chemung of Maryland; by Charles K.. Swartz. .. 0. 26.c/s03 0 28 .0e:e oie cine apele we er 679 Geological distribution of the Mesozoic and Cenozoic Echinodermata of the United States [abstract] ; by W. B. Clark and M. W. Twitchell.. 686 Age of the Gaspé sandstone; by Henry Shaler Williams.............. 688 Brachiopoda of the Richmond group [abstract] ; by August F. Foerste. 699 Reconnaissance in Arizona and western New Mexico along the Santa Hé railroad: [abstract]; by N. H. Darton.....0.2.) 2.2.5 sae 700 Geologie studies in the Alaska peninsula [abstract]; by Wallace W. AtwOOd "ls ile eee lee eS ats ee ee ale OER er 700 Some features of the Wisconsin Middle Devonic [abstract]; by H. F. Cleland Pires Bee Pe isteie scre ek PES 2 Ue 701 Ice-borne boulder deposits in mid-Carboniferous marine shales [ab- stract] ¢ by Joseph Acs Tall o. 20... 0... 2. eS cola eats oe 701 REPORT OF THE COUNCIL 609 Page Relationships of the Pennsylvanian and Permian faunas of Kansas and their correlation with similar faunas of the Urals [abstract]; by Te, Wail TEXS SUS Oe BIS Rh aii! be A ok a ge RE ee 702 Nineteenth Annual Report of the Committee on Photographs......... 703 Titles of papers presented before Section E of the American Associa- HOMO Ene AGVANCeMent OF SCIENCE oa alc ccsie s fer ee) alee) ¢ ovis eh ois wiieles 703 ererister of the Baltimore meeting, 1908. .........0..0cc cb ew cedaswesaces 705 Sessions of the Cordilleran Section, at Stanford University, California, Wednesday and Thursday, December 30 and 31, 1908............. 107 Titles of papers presented before the Cordilleran Section............ 707 Proposed form of seismograph intended to give a direct indication of TE TROIUES) PRI OSIB CS Oy Villa Joes Dre NOL Go edo pop ceo be a olod on 707 Accessions to the Library from November, 1908, to October, 1909.......... Talal ish on Officers, Correspondents and Wellows...........cccccsseseccsccs 721 TLS Le ihe WG) RIEIA MOLT ee | MUON eb RROD Is te Pa amin Weng ir eR ne (BX SESSION OF TUESDAY, DECEMBER 29 The Society was called to order at 10 a. mM. with President Calvin in the chair, and was cordially welcomed to Baltimore by Professor W. B. Clark in a few well chosen remarks, to which appropriate response was made by President Calvin. The report of the Council was called for, and was presented by the Secretary, in print, as follows: REPORT OF THE COUNCIL To the Geological Society of America, in Twenty-first Annual Mecting assembled: The regular annual meeting of the Council was held at Albuquerque, New Mexico, in connection with the meeting of the Society, December 30 and 31, 1907. ‘There have been no special meetings during the year, but some business has been transacted by correspondence. The details of administration for the twentieth year of the existence of the Society are given in the following reports of the officers: SECRETARY’S REPORT To the Council of the Geological Society of America: Meetings.—The proceedings of the annual meeting of the Society held at Albuquerque, New Mexico, December 30 and 31, 1907, have been recorded in the closing brochure of volume 19 of the Bulletin, which is now in press. 610 PROCEEDINGS OF THE BALTIMORE MEETING Membership.—During the past year the Society has lost two Fellows by death: Homer T. Fuller and Wilham 8. Yeates, and two by resigna- tion. ‘The names of the four Fellows elected at the Albuquerque meeting have been added to the list, all of them having completed their member- ship according to rule. The present enrollment of the Society is 294, the same as at the time of making the last annual report. Fourteen candi- dates are before the Society for election, and several applications are under consideration by Council. Distribution of Bulletin.—There have now been distributed 16 bro- chures, comprising 346 pages, of volume 19, and the remaining 6 bro- chures, including the Proceedings, are in the hands of the printers in various stages of completion. By action of the Publication Committee no manuscripts were accepted by the Secretary after October 1, in an effort to finish the volume within the calendar year. With this arrange- ment the volume could have been completed as desired if the authors had been more prompt in returning the corrected proots. The irregular distribution of the Bulletin during the past year has been as follows: Complete volumes, including one complete set, sold to Fellows, 20; sold to the public, including one complete set, 166; sent out to supply delinquents, 2; brochures sent out to supply deficiencies and delinquents, 106; sold to Fellows, 37; sold to the public, 42. ‘Three copies of volume 18 have been bound for the use of officers and the library, and one has been bound and presented to Dr I. C. White by order of the Council. Bulletin Sales——The receipts from the sale of the Bulletin during the past year are shown in the following table: SECRETARY S REPORT 611 Bulletin Sales, December 1, 1907, to December 1, 1908 Complete volumes. Brochures. | Grand total. Fellows.| Public.| Total. |Fellows.} Public. | Total. Wome f.......... $4.50 | $10.00 | $14.50 | $1.00 | $1.60 | $2.60 | $17.10 Molame 2....,.... APSO une LOR OO) |i ae Oss nccra: IL 1S) 1s) 15.65 Holme 3......... 4.00 15.00 19.00 AACA neta ieee eee . 20 19.20 Molume 4:........ BeOS OO MeeeO leis 30 .30 18.80 MolmumMe H......... 4.00 | 10.00 | 14.00 30 45 75 14.75 Molume) 6......... 4.00 | 10.00 | 14.00 .60 1.55 2S 16.15 Wolmme 7......... 4.00 | 10.00 |) 14.00 25 1.00 1EZ5 15.25 Wolume 8......5.. 4.00 10.00 PA SOO es ase .30 3d 14.35 Wolume 9.5....... 4 00 10.00 AS OOS | ert oe es, 1.20 20 15.20 Wolume #0......... 4.00 | 10 00 | 14.00 10 20 30 14.30 Wolume tt. ........ 4.50 15.00 19.50 .00 .90 1.05 20.55 Wome N26... 4.00 20.00 24.00 WOOTEN omea e's 1.00 25.00 Woltme 13... .6.5... 4.50 20.00 24.50 eZ MNS Eee Ss 1.20 20.70 Wolume 14......... 4.50 | 30.00 | 34.50 30 20 1.50 36.00 Wolumel5;........ 9.00 45.00 54.00 95 eNO 2.05 56.00 Nolume 16......... 9.00 | 35.00) 44.00 90 7d 1.65 45.65 Hfolume PA... 5..... 10.00 | 70.00 |) 80.00 5.40 2.85 8.25 88.25 role des. ss... |. eee cc ee 160.00 | 160.00 2.65 2.99 5.60 165.60 rome lg... 5.2... sees 300.00 | 300.00 20 .90 els) BOL IO) Rinume 20)... cs. |... eee Sac O) al eg ceo ORB) OH eect aoe Re ieee a eg | MN 37.50 LOG See ae $86.00 |$842.50 |$928.50 | $15.55 | $18.10 | $33.65 | $962.15 Neder). 2... 4.50 5.00 Oe Od pea ny rete ellen dies dea aul oe tes es 9.50 $90.50 [$847.50 |$9388.00 | $15.55 | $18.10 | $383.65 | $971.65 Deductions: Neimossion toreigneexchanve \. 22.2.2 jelene seid 08 wae 0.21 Clenicalerror i traNSMMSSIONY 222% cansses. es es ee es 05 —_ -— 26 $971.39 Receipts for the fiscal VCE eet ied at hee, Watt Sete tobe ae $971.39 revOUsly TEPOLtCO sak isis delle 2% Seba eae Saale oehel sae’ ¢ 10,274.12 otal receipts tomate: Aa “body d tetas Son ah $11,245.51 Charged, but not yet received : MiP ACCOUNT? fs Notes ceaiate | hee Aca e UMital acs Oa 17.00 mhobell Sales tov aterrmee re canes ae cog e tl kelenchores $11,262.51 The bills for volume 19 have not yet been sent out to volume sub- seribers who do not pay in advance, and the table given above includes only actual payments. The cost of publishing the Bulletin, volumes 1-18, has been $33,414.91, the average cost per volume being $1,995.38. These figures, however, do not include the expense of distribution. The number of pages and illus: 612 PROCEEDINGS OF THE BALTIMORE MEETING trations in the volumes has increased so much during the past few years that the price of subscription for libraries and foreign individuals has been raised to $7.50 by vote of Council. Hxpenses.—The following table gives the cost of administration and of Bulletin distribution during the past year: EXPENDITURE OF SECRETARY’S OFFICE DURING THE FISCAL YEAR ENDING NOVEMBE 30, 1908 Account of Administration Rostaze and telesrams » 05 0ih ccs we Cols Sores ik ee ee $64.14 RITES ole LiskG's Sees Sie usta’: eete eee euetece la eke mole clap atetonsties ee see 6.59 Stapioneny and primving chee -ocahe ec es er cree hel pret aetna 168.30 Aadressocraph plates! 22.3 hehe =p cha eee oie sere ee 2.34 Mraveliie sites 2 sae Be Ae ee AO aes STEIN ant APM SEN SG o 5 6.50 HaabOrer 225s. ba ane ARS SEIS seo e te veet ORS OMENS On Fel a eee et 00 iixpenses of ‘Cordilleran Section: -- esse). eee eee Bee 2.50 Potal s..bcscas Whe ois cele cvere Mee sees ae oe RN eee ee $250.88 Account of Bulletin Postagen |. Eaece eck unis Gite ap eicthortersclie seieeieiets a PY 5.4 2 - $130.48 i Dp-¢ 0) decicin Geeaaesiot Nae prenns ba dicts Guay ose Pio ie tate eo cls ae 37.76 @olléction of checks, 25.250%e. es 2 ee ee oe stern oe 1.85 NH 010) =) een aN Ren aa ier Paes UML Mor ae MTOR HIM AI ya GOR o'Bon oc 0 © 4.25 SiatrOme tay card sO tenses e heat ete heeietae ets a enna ete, ete 45.68 Refund of overpayment on, Bulletin 24222222 se.) eee 5.90 Potal Hes slic We es as wee iste seh ie eee 225.02 Total expenses for the year! ......).)5 00 50..2 e+ see ee $475.90 Respectfully submitted. ; EpMuUND Otis Hovey, New York, December 17, 1908. Secretary. TREASURER’S REPORT, 1908 To the Council of the Geological Society of America: The Treasurer herewith submits his annual report for the year ending December 1, 1908: Two (2) Fellows, J. S. Diller and G. C. Martin, have commuted for life during the year by the payment of one hundred dollars each, thus in- creasing the total Life Commutations to eighty-five (85), which, with four (4) Honorary Life Members, makes a total of eighty-nine (89), of whom eighty-one (81) are now living. | One (1) Fellow is delinquent for four years, five (5) Fellows are delin- quent for three years, eight (8) Fellows are delinquent for two years, and TREASURERS REPORT 613 are therefore liable to be dropped from the roll for non-payment of dues, in accordance with section 3, chapter 1, of the By-laws; seventeen (17) Fellows are delinquent for the present year. The membership of the Society, including delinquents, aggregates at the present time 294, of whom 81 have commuted for life. been two resignations and two deaths during the past year. _ With the advice of the Investment Committee, the Treasurer bought during the year a one thousand dollar bond of the Saint Louis, Iron Mountain and Southern railroad, at a cost of $979.09. RECEIPTS Balance in treasury December 1, 1907......... Mellowship fees 1904 (1)....6....ccccececves Cae “ 1905 (4) 1906 1907 1908 1909 eoeeeece ee eee ee ee eos eoeceoseseoscee seo ee ee eee eceesceer cee eres eeoes coerce ee ee eee eeee Initiation fees Interest on investments: Iowa Apartment House Company........ Ontario Apartment House Company..... Texas and Pacific Railroad bonds........ U. S. Steel Corporation bonds............ Saint Louis, Iron Mountain and Southern Railroad bond Interest on deposits in Baltimore Trust Company corer ees ere eee eee eee eee eee Collection charges added to checks............ EXPENDITURES Secretary’s office: Administration Bulletin Secretary’s allowance eceveveevee ee ees ees eee Treasurer’s office: Postage, safe deposit box, etcetera....... Treasurer’s allowance for clerical hire... Librarian’s office (CO at AMG PAR ENA Mirereommiutarions (2) 0.2.6... se sec cece ws ores eeececevorwrereere eee eee eer eee ee see 8 © eoreer ee eee ore er ee eee eee ee ee ew $250.88 229.27 500.00 $1,434.15 2,290.00 40.00 200.00 $980.15 There have $5,568 .55 614 PROCEEDINGS OF THE BALTIMORE MEETING Publication of Bulletin: Printing: | .)4¢ acces eis ce eee eile atc Grate rater $2,086.28 EINSTAVINE % | rete eerste m she -c «/4) olete or epereneeere 382.32 Nditor’s allowanmeega. cn vs oso sien eee 250.00 2,718.60 Investment : Saint Louis, Iron Mountain and Southern Ratlroad S000 “bond... shoei. eee oor 979.09 $4,772.72 Balance on hand December 1, 1908.............ccceees 795.83 $5,568 .55 Respectfully submitted. Wm. BULLOCK CLARK, BALtTIMorRE, December 6, 1908. Treasurer. Epitor’s REportT To the Council of the Geological Society of America: The Editor takes pleasure in being able to state that, although the Proceedings brochure will not be in readiness for distribution prior to the winter meeting of the Society, the entire text of volume 19 is in type. As the usual meeting of the Cordilleran Section was omitted, volume 19, both in pages and illustrative matter, is somewhat reduced—indeed, in regard to the former, it but slightly exceeds the average of the first twelve volumes issued by the Society, while in the latter respect it falls short of that average. The average of the first twelve volumes was 577 pages and 43 plates, while the present volume has 617 pages and is illus- trated with 41 plates and 31 text figures. The following tables bring the statistical information down to date: oa eree-| Vol. 13. | Vol. 14. | Vol. 15. | Vol. 16. | Vol. 17. | Vol. 18. | Vol. 19. pp. 577. | pp. 583. | pp. 609. | pp. 636. | pp. 636. pp. 785. | pp. 717. | pp. 617. pls. 43. | pls. 58. | pls. 65. | pls. 59. | pls. 94. | pls. 84. | pls. 74. pls. 41. Illustrations...... 327.62 ATT.27 431.21 457.76 706.97 608.68 486.22 289.92 Tetter-press.......] $1,575.14 | $1,647.12 Skee $1,817.03 | $2,087.98 | $2,015.68 | $1,591.32 $1,902.66 | $2,124.39 | $2,088.71 | $2,118.97 | $2,524.00 | $2,696.66 | $2,501.90 | $1,881.24 Average per PALER. eosces $3.30 $3.64 $3.43 $3.33 $3.96 $3.37 $3.42 $3.00 EDITOR'S REPORT 615 Classification. SS Tey eee mite eh ce ale ilies a an aS oat 6 eS} 5 HS x : bp S 5 ae! = ee aie Orne nals SS fh Re e) re o = OO! S og] = WW! OW] .S 5. g x (des| 2 |ak| © | hS1 he) ke) ee) 3 & 2 |g on 5 en a oS Be mol S fo} o|zBO a a AH Wolume. | = |x Se lia Col oe Ol Oo] esse otal. & P S =~ oN 2) fof) s on Ta oN 5 ES 5 3) 4 Lic = Y ) S eee ey ee ae We aie iS St as Number of pages. iL. ee ORNS 292 TS eke Aa ay olee 3. 60 | 4] 4 | 598-+-xii 2, BOE ON YOK) PE soz) 16S Ay 9 Ho 9 LF 1662-Sxiv eee exe DO ek | Ata Ate S22 tase) 104. es... 61 | 15 | 1 | 5414+xi Ae eee mA eto on lone 4s loge mmioee iy Asha 47 | 32 | 2 | 458+-xii Mcyaceils sis ISS Ne By abs NPA ai NO eG 71) 14) 9 | 665+xi1 Cae BO | JU | eB ae Bs) Dis yer se 63 | 25 | 4 | 5388+x 7s tee 5) CMOS 4 BB AO Weal jh aes 4 O67 928) Pls | oa8ax Geers oce > + 34 | 50} 98 De 43) Od) | as ie LA LOS) ee ALO Xs Th ea Sela BN MOA ME ISy Me oe al 44} 28 | 64] 16 64 | 12 |....) 460-+x Oa So oon le 9G) tot lOO) 162) ee68) | 28 84 | 27 | 17 | 5844-x11 BGI 2 Coe elon a Ze OM oa) isle ens fi 71.) 60 | 46 | 651-++xii 12 ROG R 39s 09 |) O35) |) 24 1) 98 5 5 (ON ees 5 Oeis 4 all 2a am ii alse 2a 28, Lier ler? 4 || 165.) 32 | 29 | 5838+xii 114) eapeege ASA NAS. le OON oon tells i 22 1 80 | 14} 1 | 609+xu Jae 26 | 124 Bl OBE lr SOa BAR owes dlloo Gb Ti Wilt 3.) 636-—x Heres se CA 1S 2 oO OD sr ee4l TOR eee 67 | 22 | 15 | 636-++-x11 Ile OTRO M i As) NOAA MA NW aZOAN | ODT Wn. 1h | 9 | 2) | 785-Exav LC eae 16 | 164 | 141 5 | 29 | 246 BAe woe 68 | 40 | 3 | 717+ xii MOR ae GROG vile eZO MeO Ne OO. | loge lyn Soe lanes 06 | 15 | 20 | 617+x Respectfully submitted. JOSEPH STANLEY-BRown, Cotp Spring Harsor, N. Y., December 18, 1908. Editor. LIBRARIAN’S REPORT To the Council of the Geological Society of America: The list of accessions to the library for the year ending November 1, 1908, has been forwarded to the Secretary for incorporation in volume 19 of the Bulletin. The expenses of this office for the past year are as follows: To 500 U. P. U. postals and printing of Sane let WM A ea ne $11.00 LE: GILSSTTES QUT OM EOE a RR RR tors RE BRN Veoa cc aot Nee tc Re a 5.00 23: (DOS OO ah wed eS Br eae ee tries Beek oie TTI ia eile tae oe eR ee 1.25 Ligh (ESR JOIR SISSIES aa ae nS er VS 8 acclnc ce am eR Seg .40 $17.65 Respectfully submitted. H. P. CusHINe, CLEVELAND, Out0, December 4, 1908. Inbrarian. 616 PROCEEDINGS OF THE BALTIMORE MEETING On motion, the report of the Council was laid on the table for one day, according to custom, and G. K. Gilbert and J. E. Wolff were elected a committee to audit the accounts of the Treasurer. . ELECTION OF OFFICERS President Calvin then announced the result of the balloting for officers for 1909, as canvassed by the Council, and declared the following officers elected: President: GRovE K. GILBERT, Washington, D. C. First Vice-President: FRANK D. ApAms, Montreal, Canada. Second Vice-President: JOHN M. CuarKe, Albany, New York. Secretary: Epmunp Otis Hovey, New York city. Treasurer: WILLIAM BtuLiock CuarK, Baltimore, Maryland. Editor: JOSEPH STANLEY-Brown, New York city. Inbrarvan: H. P. CusHine, Cleveland, Ohio. Councilors: GEORGE Otis SmitH, Washington, D. C. Henry 8. WasHIneTON, New York city. ELECTION OF FELLOWS The Secretary stated that the candidates for fellowship had been elected by the transmitted ballots. The list is as follows: ELIOT BLACKWELDER, A. B., Madison, Wisconsin. Assistant Professor of Geol- ogy in the University of Wisconsin. WILLIAM Puipps BuAKke, Ph. B., Tucson, Arizona. Director of the School of Mines, Arizona, and Territorial Geologist. te hie at ee 2 NS a BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 102 ELECTION OF FELLOWS 617 CHARLES WILSON Brown, Ph. D., A. M., Brown University, Providence, Rhode Island. Assistant Professor and Head of the Department of Geology, Brown University. FRANK Carney, A. B., Granville, Ohio. Professor of Geology, Denison Uni- versity. EDWARD SALISBURY DANA, A. B., A. M., Ph. D., 24 Hillhouse avenue, New Haven, Connecticut. Professor of Physics and Curator of the Mineralogical Col- lection, Yale University. C Cassius ASA FisHeEr, A. B., A. M., 1832 Baltimore street N. W., Washington, D. C.; U. S. Geological Survey. ALBERT JOHANNSEN, B. S., Ph. D., U. S. Geological Survey, Washington, D. C. GEO. FREDERICK Kay, M. A., State University of Iowa, Iowa City, Iowa. Pro- fessor of Mineralogy, Petrography, and Hconomic Geology, State University of Iowa. Henry LAnpses, A. B., A. M., University Station, Seattle, Washington. Pro- fessor of Geology, University of Washington, and State Geologist of Wash- ington. GEORGE BuRR RICHARDSON, S. B., S. M., Ph. D., Washington, D. C. Assistant Geologist, U. S. Geological Survey. JOAQUIM CANDIDO DA Costa SENA, Engenheiro de Minas pela Escola de Minas de Ouro Prato, Brazil. Director of the State School of Mines and Professor of Mineralogy and Geology. HARLE SLOAN, Charleston, South Carolina. State Geologist of South Carolina. GEORGE WILLIS SToSE, B. S., U. S. Geological Survey, Washington, D. C. Geol- ogist and Editor of Geologic Maps. CHARLES KEPHART Swartz, A. B., Ph. D., Baltimore, Maryland. Associate Pro- fessor of Geology, Johns Hopkins University. On call of the President, memorials of the Fellows who had died since the Albuquerque meeting were presented by title as follows: MEMOIR OF HOMER T. FULLER BY EDMUND OTIS HOVEY* Dr Homer T. Fuller, son of Sylvanus and Sarah M. (Taylor) Fuller, was born at Lempster, New Hampshire, November 15, 1838, and died at Saranac Lake, New York, August 14, 1908. He was prepared for college at Kimball Union Academy, and gradu- ated from Dartmouth in 1864 at the head of his class. After serving three years as principal of the Fredonia (New York) Academy, he spent two years in study at Andover and Union theological seminaries, and then became pastor of the Congregational church at Peshtigo, Wisconsin. He remained there two years, and then returned to the teaching profession as principal of the Saint Johnsbury (Vermont) _1The author desires to acknowledge his indebtedness to Professor B. H. Finkel, of Drury College, for data used in the preparation of this notice. 618 PROCEEDINGS OF THE BALTIMORE MEETING Academy. In 1882 Doctor Fuller became president of the Worcester (Massachusetts) Polytechnic Institute, remaining there till 1894, when he accepted a call to the presidency of Drury College, Springfield, Mis- sourl. He filled this post most acceptably till age and broken health compelled him to retire from active life in August, 1905. After this he spent his summers at Fredonia and his winters in the south. Early in the summer of 1908 a severe attack of bronchitis left him in a much weakened condition and pulmonary tuberculosis supervened, and after only a few weeks of treatment, when the most sanguine hopes were enter- tained as to recovery, he was suddenly seized with hemorrhage of the lungs and died on August 14, 1908. | Doctor Fuller was an Original Fellow of our Society, but his published papers on geological topics number only three, and all of them are ex- tremely short. He was a teacher and an administrator rather than an investigator. At Saint Johnsbury he gave instruction in the earth sciences, and at Worcester he had the department of geology and min- eralogy, “bringing it up to a high standard and making a fine collection of specimens for illustration as well as laboratory work.” At Drury he had little time to devote to science. On the administrative side, Doctor Fuller’s monument is the increased endowment, facilities, enrollment, and general efficiency of the institu- tions of which he was successively at the head. He bore a high reputation for his work and his accomplishments among the college presidents of the middle west. In 1880 he received the honorary degree of Ph. D. from Dartmouth College; in 1898 the degree of D. D. from Iowa College; in 1905 the degree of LL. D. from Drury on his retiring from the presi- dency. BIBLIOGRAPHY Effects of droughts and winds on alluvial deposits of New England. Bulletin of the Geological Society of America, vol. 3, 1892, pp. 148-149. Preservation of glaciated rocks (Massachusetts). (Abstract.) Proceedings of the American Association for the Advancement of Science, vol. 39, 1891, p. 246 (44 page). Corundum and emery. Drury Collection, Bradley Field Geological Station, vol. i, 1904, pp. 31-33. MEMOIR OF W. 8. YEATES BY GEORGE P. MERRILL William Smith Yeates, State Geologist of Georgia, died at his home in Atlanta on February 19, 1908. Mr Yeates was born in Murfreesboro, North Carolina, December 15, 1856, and graduated at Emory and Henry BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 103 Tam, sincerely yours, State Geologist. MEMOIR OF W.S. YEATES 619 College, Virginia, in 1878, receiving the degree of B. A., and that of M. A. in 1881. Soon after graduation he accepted a position with the United States Fish Commission, and in the winter of 1880-1881 became assistant in mineralogy to Dr George W. Hawes, then recently appointed Curator of Geology in the newly created Department of Geology in the National Museum at Washington. After Doctor Hawes’ death, in 1883, Mr Yeates remained in charge of the mineral collections, as Assistant Curator and Acting Curator until May of 1893, when he resigned to assume the position of State Geologist as above noted. During 1884- 1893 he also held the position of Professor of Mineralogy and Geology in what was then the Corcoran Scientific School of Columbian (now George Washington) University. Mr Yeates’ position in scientific circles, as may be readily inferred from the above, was that of administrative officer, rather than original investigator. He was, however, an enthusiastic collector of minerals and thoroughly imbued with the museum idea, a quality first developed dur- ing his period of service in Washington, and subsequently matured in connection with the State Survey. Indeed, his taste and judgment in the selection of specimens and their installation for exhibition was perhaps his strongest characteristic, and the exhibits illustrating the resources of Georgia, made under his direction at Buffalo, Saint Louis, and other of the great expositions of recent years, were in these respects not excelled and rarely equaled by those of any other state. The Geological Museum now in Atlanta is wholly of his conception and execution and a worthy monument to his aptitude along these lines. For the reasons above noted, few papers containing the results of original investigations bear Mr Yeates’ name. Under his administration a series of preliminary reports have been issued, covering the subjects of building stone, manganese, phosphates, ochres, coal, gold, and other economic deposits, as well as water-power and muagergsound waters of the state. Mr Yeates was married in 1884 to Julia Ward Moore, of North Caro- lina, who, with two sons, survives him. He was a member, in addition to the Geological Society of America, of the American Association for the Advancement of Science, the American Institute of Mining Engineers, and the Philosophical and Geological societies of Washington. After presentation of the memorials of the deceased Fellows the regular program of papers was taken up as follows: The first paper read was 620 PROCEEDINGS OF THE BALTIMORE MEETING SOME DISTINCTIONS BETWEEN MARINE AND TERRESTRIAL CONGLOMERATES BY JOSEPH BARRELL [Abstract] The problem was approached by studying the effects of shore, as compared with subaerial, activities upon the production, transportation, and deposition of gravel. It was determined that the truly terrestrial forces produce vastly more gravel, spread it far more widely, and provide more opportunities for deposition than do the forces of the littoral zone. Conglomerate formations, therefore, should be dominantly of terrestrial origin. In order to determine, however, the mode of origin of particular examples, definite criteria must be drawn between the two classes. It was shown that the thickness was one of the most iniportant of these, marine conglomerates, except under local and spe- cial circumstances, being limited to considerably less than 100 feet in thick- ness, terrestrial conglomerates, on the other hand, being frequently measured in hundreds and occasionally in thousands of feet. Attention was next turned to the significance of the intercalated non-con- glomeratic beds and the relations to the under- and over-lying formations, with the conclusion that the characteristics of the associated strata are frequently of high supplemental value for determining the mode of origin. Applications of the conclusions were made to several conglomeratie forma- tions. Professor Barrell’s paper was discussed by G. K. Gilbert, J. Barrell, and W. H. Hobbs. REPORT OF COMMITTEE ON GEOLOGIC NOMENCLATURE Arthur Keith reported that the Committee on Geologic Nomenclature had organized, with = C. Chamberlin as chairman and Arthur Keith as secretary. The committee is constituted as follows: For the Geological Society of America: T. C. Chamberlin and W. B. Scott. For the U. S. Geological Survey: Arthur Keith and David White. For the Association of State Geologists: J. M. Clarke and E. A. Smith. For Canada—Geological Survey: F. D. Adams. Other official surveys: W. G. Miller. For Mexico: J. G. Aguilera. The following papers were read by title: FIRST CALCAREOUS FOSSILS AND THE EVOLUTION OF THE LIMESTONES BY REGINALD A. DALY This paper has been published as pages 153-170 of this volume. Sdigal4d WOO AMONLNAYM NYALSAM GNV NYSLSV3S NS3SML3AG NOILOANNOO YSAWHOI SO SLNVNWAY SNIMOHS dV @jS@M aje4awio|Suo> Angay Aq pajuesaudad I 40 890|d U} ajj!As|jog 49M07 ae Bf CABO] BUD) || |ASHOd Jo ajsem |, pues pue ajqgad & SOHIW S = \ mover) © yookyr\\G, Clean Moe ‘ ry v Hy \ \ MINIS} © Bie oo yea le Saranlerg PYPIPOA 9 ANON ASO} g aiyntoue, Fo 0\\ oO im *weynyyon, WW 2? NIG a 0. ON APL g \ Vr ra / \ A\\\ nso’ Ve ( aNNa\moyy, d @\\\n MAO) fo} YoPng_o a\\\Nsprsypun \~o BUPA {eles ™ ‘ aN i Raped i? oe Vowgtar t \ \ PNAS yan Wn: (rs \oxd - AS \ Syed ; ‘oho WwW ° 9, q \ ae. ME] | ee as Nida YH Pu PE ohh 0 ‘ n ; POL “Id “8061 ‘0% "10A "WV "OOS “1049 *11Nd TITLES OF PAPERS 621 PRIMARY ORIGIN OF THE FOLIATED STRUCTURE OF THE LAURENTIAN GNEISSES BY FRANK D. ADAMS AND ALFRED E. BARLOW RELATIONS OF PRESENT PROFILES AND GEOLOGIC STRUCTURE IN THE DESERT RANGES BY CHARLES R. KEYES DEFLATION AND THE RELATIVE EFFICIENCIES OF EROSIVE PROCESSES UNDER CONDITIONS OF ARIDITY BY CHARLES R. KEYES Then was read UNCONFORMITY SEPARATING THE COAL-BEARING ROCKS IN THE RATON FIELD, NEW MEXICO BY WILLIS THOMAS LEE This paper has been published as pages 357-368 of this volume. The next paper read was , EVIDENCE OF FORMER CONNECTION BETWEEN THE EASTERN AND WESTERN COAL FIELDS ACROSS CENTRAL KENTUCKY BY ARTHUR M. MILLER* [Abstract] It has been a view entertained by a number of students of Kentucky geology that the absence from the highest crest of the Cincinnati anticline of later than Ordovician up to and including the Lower Coal Measure rocks is due in the main to their removal by denudation rather than to lack of deposition. This was the opinion of Professor Shaler, who recurred to this subject again and again in the publications of the Kentucky Geological Survey while he was State Geologist, and later referred to it in his article “The origin and nature of soils,” published in the Twelfth Annual Report of the U. S. Geological Survey. In this view he was supported by W. M. Linney, W. T. Knott, and others on the Shaler and Procter Kentucky state surveys. The evidence which led to such conclusions was the presence of the waste and outliers of the newer for- mations far outside of their present continuous outer boundaries, and the ab- sence of any materials in these formations which can be recognized as having been derived from older formations exposed on the crest of a “Cincinnati anti- clinal island.” A résumé of this evidence and a discussion of its bearings was given by the writer in an article entitled “The hypothesis of a Cincinnati Silurian island,” published in the American Geologist, vol. xxii, 1898, pages 78-85. Citations giving Professor Shaler’s views’ are as follows: “The Carboniferous conglomerate . . . increases in thickness as we recede from the Cincinnati axis. It contains a great quantity of pebbles, both in the east and in the west, but not a trace has yet been found of any pebbles which could be attributed to the Cincinnati axis.”’ * Manuscript received by the Secretary of the Society December 31, 1908. 4 Report of Progress, Geological Survey of Kentucky, 1877, p. 17. 622 PROCEEDINGS OF THE BALTIMORE MEETING In the same report and on same page, referring to the near approach of the two fields in southern Kentucky, and the slight thickness of presumably worn away Strata (150 feet) that would have to be restored in order to unite the two fields, he says: “It is impossible to resist the conviction that a million of years ago, or thereabouts, this section still contained a continuous sheet of coal reaching from Wayne and Clinton counties, on the east, across to Edmonson and Hart, on the west. “T believe that the uppermost level of caves which remain open in this region were formed during the time when the hills of this section were so continuously capped with the remains of the coal fields that there could have been no doubt as to the continuity of the two fields—the eastern, or Appalachian, and the western, or Illinois, field. This original continuity being granted, the most material question as to the relations of the two coal fields is substantially disposed of. Going north or south of this line, more and more time for the erosion becomes necessary, for that erosion increases progressively, until at Nashville or Cincinnati we require a duration which is probably somewhere be- tween four and eight million of years for the completion of the down cutting from the true coal measures.” Under ‘Scientific problems,” page 48 of the same report, occurs this state- ment: “Perhaps the most valuable result of the year’s work, in a scientific way, is found in the facts that have been gathered, going to show the former existence of a complete union between the eastern and western coal fields across the region occupied by the upper waters of the Green and Cumberland rivers.- A treatise on this subject will be found in the Memoirs of the Survey.’ [This treatise seems never to have been published. ] “T will here only note that the gap between these fields, now only about sixty miles in breadth, is occupied by the waste of the old Coal Measure rocks that cap nearly every high hill. The pebbles of the conglomerate, which are peculiar in their nature and easily recognized, are found on every high point in this district; and in many places the fossil plants of the coal-bearing rocks have been found, showing quite incontestably the former existence of the beds whence they were derived over this area. Less distinct but very suggestive evidence has been found, leading us to raise the question whether the Coal Measures did not cross over the district near Lexington, bringing measures of that age into contact with rocks of a much earlier age.” In his article, “The origin and nature of soils,’* occur the following interest- ing suggestions concerning soil inheritance: “Ags soil descends with the wearing away of its materials, it of course is subjected to a constant change in its mineral character. Thus while soil of the district now occu- pied by the rich limestone territory of central Kentucky lay upon the Millstone grit it was doubtless of a sandy and rather sterile nature; when in its descent it came into the limestone bed it must have been fertile; still further down, encountering the Devonian or Ohio shale, which because of its mineral character is rather unfit for plants, the soil would again have been reduced to a sterile state. Finally, in downward migration the surface entered the rich fossiliferous beds of Silurian age, and from the storehouses of the ancient marine life it acquired the exceedingly nutritious character of the so-called blue grass soil. “As soil migrates downward, the greater part of the debris which it inherits from the rock through which it passes is dissolved and goes away to the sea. There are, how- ever, certain materials which may remain for a long time in the soil because they are peculiarly insoluble. Thus in the limestone soils of Kentucky, the greater part of which are derived from the rocks on which they now lie, we often find many flinty and cherty bits which came into the layer when it was in a geological position a thousand feet or more above the site now occupied by the soil.’’ The elaboration of this idea in Shaler’s “History of Kentucky,” in which he 2Twelfth Annual Report of the U. S. Geological Survey, pp. 302-303. FORMER CONNECTION OF KENTUCKY COAL AREAS 623 coins the happy expression “geological distribution of politics,’ and comments on how the distribution might have been affected by differing rates of denuda- tion, has been enjoyed by every student of Kentucky history. Linney’s contribution to the subject is seen in his report on Lincoln county under the head “Waste beds,” on page 26: “Over every portion of Lincoln county are to be seen the waste of beds which were once in position over those now seen in place. Corals and chert from the Corniferous -are very common. These and the geodes from the Carboniferous are hauled oft from many fields and used for repairing roads. Blocks of sandstone and masses of conglom- erate are not infrequent over the blue limestone beds. “Over the Subcarboniferous part of .the county the remains of the Saint Louis beds are seen nearly everywhere; and over these are spread, sometimes many feet in depth, the sands and pebbles of the base of the Coal Measures. There can be no reasonable doubt that all the series of rocks now seen in the county were once continuous over its surface, unless we except some of the thin beds of the Upper Silurian, and that on top of these were the Subcarboniferous limestones and the lower portion and perhaps all the Coal Measures.”’ W. T. Knott, in his report on Marion county, refers to the tops of the knobs in that county still carrying the “waste of the conglomerate, in some places consisting of quartz pebbles, well worn and masses still compacted.” The work of the present geological survey has been confirmatory of the views on this subject entertained by the workers on the Shaler and Procter surveys. Excavations in the city of Lexington and barite mining operations in the blue-grass region have brought to light Waverly geodes, which can not well be accounted for on any other hypothesis than that the beds containing them for- merly went over the “Jessamine dome” of the Cincinnati anticline. The work of the writer during the past Summer in the counties of Green, Taylor, and Adair has supplied additional proof, if such were needed, that the Coal Measures once extended across the Cincinnati anticline. The remnants still remain on the highlands that mark the dividing of the waters between the Salt and Green rivers. They exist like stepping-stones between the two coal fields. Professor Foerste had noted and mapped a tongue of conglomerate extending out from the Western coal field between the Green river and Bacon creek of Nolin river for some distance east of the Louisville and Nashville railroad. He did not trace it farther than 3 or 4 miles east of the railroad. A number of years ago the writer had noticed a belt of conglomerate waste crossing the old Bardston and Nashville turnpike south of Magnolia, and during the past summer found a continuous belt of it, forming the highland along the boundary of Green-Hart, Green-Larue, Taylor-Larue, and Taylor-Marion counties. This conglomerate is much disintegrated; still it is a very heavy deposit, estimated to be 50 feet thick, and much of it is practically in place. The pebbles of it are remarkably large, many of them being as large as hens’ eggs, whereas the usual size for the conglomerate pebbles in Kentucky is that of pigeon eggs, or even as small as large peas (hailstone-grit). Where in place, or nearly in place, it rests on Saint Louis limestone, which is also generally badly disin- tegrated and indicated mainly by abundance of chert, a conspicuous element of which is silicified Lithostrotion canadense and L. proliferum. There is no sign of the Kaskaskia (Chester) in this region, though immediately south of the Green river the knobs are capped by Kaskaskia, with no sign of the waste of LX—BULL. GEOL. Soc, AM., Vou. 20, 1908 624 PROCEEDINGS OF THE BALTIMORE MEETING the conglomerate overlying it. Such a knob is Maxey, a mile west of the vil- lage of Defriese, in Hart county. There is also a knob on the north side of the river near Rio, in the same county, which is capped by Kaskaskia. There is every evidence that the erosion interval antecedent to the deposition of the conglomerate was greater here than in most other places. Though now occupying a watershed, the remnants of the conglomerate seem to be parts of a continuous belt of channel deposit which had a transverse course across what is now a saddle in the Cincinnati anticline. In its channel deposits aspects it resembles the conglomerate of the Rockcastle river and Roundstone Creek drainage of the Hastern coal field, as described by M. R. Campbell in his ‘‘Re- port on the geology of the London quadrangle.” . Underneath the conglomerate, on the boundary between Green and Larue counties, there is an iron ore (limonite) which was formerly smelted in that region. It has the same geological position and appearance as the Red River iron ore of the Hastern field. The topography of the country is also very similar. Narrow comblike ridges lead away from the main dividing ridge, which is here a part of “Mul- drows hill.” The culture features are also similar. To one traversing this region along the ridge roads winding through forests of chestnut and oak ‘im- ber, with here and there a one- or two-room log cabin, surrounded by a small clearing, it is hard to divest oneself of the idea that he is in the Hastern Ken- tucky coal field. With such similarity in natural surroundings one is not sur- prised to learn that now and then a wild turkey is seen, that wildecats are jot unknown, feuds not uncommon, and that the moonshiner is not entirely extinct. Eastward from this point, along the boundary between Taylor and Marion, and across Casey county to the headwaters of Green river, in Lincoln county, the remnants of the conglomerate along the crest of Muldrows hill become more discontinuous and are represented by thinner and more disintegrated Southward flowing streams in Taylor county have distributed this waste «o wide areas, and there are few places as far south as the latitude of Campbe ville where a search for conglomerate pebbles in the soil will not reveal tbh presence. There is a rather remarkable belt of pebble waste along the divid.ng ridge between Casey and Robinson creeks on the boundary between Casey and Taylor and Adair and Taylor. The presence of these patches of waste is indi- cated by dots on the map. Lack of accurate mapping of Casey makes it impos- sible to indicate the position of these in that county with precision, but the pebbles and masses of conglomerate are known to occur on the tops of all the high knobs into which Muldrows hill breaks up as it approaches the head of Green river. Beyond the Green river we know that the high lands are covered with this waste. Linney refers to it in his “Report on Lincoln county,” and the writer can confirm this so far as the top of Kings mountain is concerned. This ear- ries us to the confines of Rockeastle county, where the outliers of the Eastern Coal Measures set in, at first non-conglomeritic, but as the vicinity of Round- stone creek and Rockecastle river is approached the lower measures become more pebbly, and massive conglomerate cliffs are the conspicuous features of the landscape. - It seems, therefore, that the facts here presented warrant the inference that a continuous belt of Lower Coal Measures formerly extended across southern Kentucky from the Appalachian to the central fields. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 105 FIGURE 1.—THE FISSURE FROM THE TOP OF THE CLIFF This view shows the succession of the rocks and the amount of displacement, which is slightly more than the height of the man standing on the sunken block at the left; the amphitheater which formed one wall of the rounded point is also shown in the distance. Photograph by Frank Carney. FIGURE 2.—VIEW OF THE FISSURE ABOUT FORTY FEET BELOW THE SURFACE The contact of Cleveland and Chagrin shales is shown immediately above the large weathered joint plane in the Chagrin; the dimensions of this plane are 95 by 14 feet, as far as could be measured; it is believed that this surface largely influenced the position of the crack. Photograph by Frank Carney. LANDSLIDE IN SHALES AT CLEVELAND, OHIO TITLES OF PAPERS 625 Then was read BEARING OF THE TERTIARY MOUNTAIN BELT UPON THE ORIGIN OF THE EARTH’S PLAN BY FRANK BURSLEY TAYLOR This paper will appear in volume 21. It was discussed by H. F. Reid, _B. K. Emerson, J. Barrell, W. H. Hobbs, A. P. Coleman, and F. B. Taylor. The session adjourned at 12.30 P. M. The Society convened again at 2.10 p. M. in two sections. The first paper read in the main section, under the chairmanship of President Calvin, was ON FAULTS BY HARRY FIELDING REID This paper has been published as pages 171-196 of this volume. This was followed by MASS MOVEMENTS IN TECTONIC EARTHQUAKES BY HARRY FIELDING REID These two papers were discussed by W. H. Hobbs and H. F. Reid. The next paper was read by title ALASKAN EARTHQUAKE OF 1899 BY LAWRENCE MARTIN* The Society then listened to the oral presentation of the paper: LANDSLIDE ACCOMPANIED BY BUCKLING, AND ITS RELATION TO LOCAL ANTICLINAL FOLDS? BY FRANK R. VAN HORN Contents Page PBECORTNGLIOH irs’ s cele cc's «icicles eee vale se neue eee aces etatetenod-yearencnentaelctten traens ov cucsaey or 626 Preuss WRENCH LOLTOM We cone) ols te ye! aleleitt vieloie such a pressure as would seem necessary. With this Cleveland landslide as an object lesson, the writer has come to the conclusion that elsewhere anticlines of local character, especially in shales, may have been produced by landslides similar to the one which is the subject of this paper. OTHER LANDSLIDES OF SIMILAR NATURE During the discussion of the above paper at the Baltimore meeting Doctor J. W. Spencer?’ called attention to a landslide which took place April 15, 1884, 2A landslide at Brantford, Ontario, illustrating the effects of thrusts upon yielding strata. American Naturalist, 1887, p. 267. LANDSLIDE AT CLEVELAND, OHIO 631 on the Grand river, about 2 miles southeast of Brantford, Ontario. The bank was 90 feet high, and at the top was composed of 20 feet of thinly bedded sandy Saugeen clay, while the remainder consisted of Erie clay, which was also finely stratified. ‘Owing to the forward movement and reaction, the deposits of the Erie clay have been raised into perfectly truncated anticlinal folds, which are composed of vertical strata more or less twisted.’ These “truncated anticlines’” were probably due to vertical jointing in a very thick mass with considerable lateral displacement. The behavior of the layers of Hrie clay seems similar to that of two blocks of wood of equal length made into a horizontal column which is free to “fail” upwards. A heavy horizontal thrust applied with enough eccentricity to produce failure will make the blocks fly upward at the center and show the end of the grain, and would therefore resemble a truncated anticline. It would seem to the writer that | the Brantford slide does not show the same type of thrusting as that of the Cleveland occurrence, which did not have as much lateral translation. Dr G. B. Richardson cajled my attention to a paper read at the Rochester meeting in 1902 by T. C. Hopkins and Martin Smallwood.*? However, there was nothing published but an abstract, which read as follows: “‘A number of unique folds occur in several small and rather deep ravines in the vicinity of Meadville, Pennsylvania. They are limited in extent, both vertical and linear, and so far as known occur only in the bottom of ravines. The relation of the folds to certain landslip terraces suggests a cause for these folds.” This abstract seemed to deal with phenomena so similar to the Cleveland landslide that the author wrote to Professor Hopkins to inquire if anything further had been published on the subject, and has just received a copy of the original paper. The rocks are sandy shales belonging to the Cuyahoga stage of the Lower Carboniferous, and there are several folds exposed in four different ravines. In every case where anticlines occur they are found to be in prox- imity to what Dr G. K. Gilbert calls landslide terraces.’ The conclusion of the paper is as follows: “In view of the conditions as described above, the writers conclude that the small folds in the ravines in the vicinity of Meadville are caused partly if not wholly by landslides on the steep hillsides bordering the ravines.” CONCLUSION The Cleveland landslide, which has been described in this paper, was caused by a weakening of the shale rocks at the base of the cliff by various erosive agents, possibly assisted by blasting. This resulted in a sinking of the outside part of the valley wall, which produced a tension that caused a portion of the cliff to crack off. The dislocated mass then rested on an inclined plane, so that its weight had both vertical and horizontal components, which produced sufficient pressure to cause the shales of the valley fioor to buckle and the separated block to settle on its base. In this case the vertical pressure was 3’T. C. Hopkins and Martin Smallwood: Some anticlinal folds. Bulletin of the Geo- logical Society of America, vol. 13, p. 530. 47T. C. Hopkins and W. M. Smallwood: Discussion of the origin of some anticlinal folds near Meadville, Pennsylvania. Bulletin of Syracuse University, series IV, number i, Jon ales 5 Grove Karl Gilbert: Lake Bonneville. Monograph I, U. S. Geological Survey, p. 83. 632 PROCEEDINGS OF THE BALTIMORE MEETING more important, and was considerably greater on the outer base of the slide, since it was resting on an inclined plane. It is believed that other anticlines of local nature, especially in shales along stream valleys, have been caused by landslides in a manner similar to the one which has been the subject of this paper. This paper was discussed by H. P. Cushing, J. W. Spencer, G. B. Richardson, Frank R. Van Horn, G. K. Gilbert, and G. H. Ashley. Then was read by title THE VOLCANO KILAUEA BY C. H. HITCHCOCK After this was presented orally MOUNT PELE OF MARTINIQUE AND THE SOUFRIERE OF SAINT VINCENT IN’ MAY AND JUNB, 1908 BY EDMUND OTIS HOVEY [Abstract] The paper gave the results of an expedition made to the Lesser Antilles in April to July, 1908, illustrating by means of lantern slides the progressive changes in 1902, 1903, and 1908 due to the great eruptions and the efforts of nature and man to recover from them. A part of the paper is published under the title, “The clearing out of the Wallibu and Rabaka, Saint Vincent, gorges,” as pages 417-426 of this volume. The last paper of the afternoon was presented orally. It was MULTIPLE GLACIATION IN NEW YORK BY H. L, FAIRCHILD [Abstract] Evidence of pre-Wisconsin glaciation in territory surrounding New York State—in Canada, Ohio, Pennsylvania, New Jersey, and New England—implies a similar history for the state. ; An accumulating body of facts points to at least two ice invasions. Such features are: (1) the widespread occurrence of more or less difference between the surficial and the deeper till, as shown in color, texture, composition, with sometimes a distinct surface of separation; (2) weathered glaciated surfaces and heavy glacial flutings merely scraped in places by a later abrasion; (3) old planation surfaces which, though protected by Wisconsin till, have lost their glaciated character; (4) probable stream channels not the product of the latest glacial drainage; (5) physiographic features of anomalous relationship. No interglacial deposits have as yet been found. SESSION OF WEDNESDAY, DECEMBER 30 633 This paper was discussed by G. K. Gilbert, R. S. Tarr, F. Carney, A. Penck, and A. P. Brigham. Adjourned at 5.25 o’clock. The Society met at 8 o’clock Tuesday evening, in the lecture-room of the geological department, to listen to the presidential address of Pro- fessor Samuel Calvin, who chose as his theme “Present phase of the Pleistocene problem in Iowa.” This paper has appeared as pages 133-152 of this volume. At the close of the address the Society and its friends adjourned to the rooms above the lecture-hall and participated in a “smoker” as the guests of the geological department of the university. SESSION OF WEDNESDAY, DECEMBER 30 Wednesday morning the Society came to order in general session, President Calvin presiding, at 9.35 o’clock. The Council report was, on motion, taken from the table and adopted. The Auditing Committee reported finding the Treasurer’s accounts correctly cast and properly vouched. The report was adopted. The Secretary then read a letter from Hon. Gifford Pinchot, chairman of the National Conservation Commission, requesting the appointment of a committee by the Geological Society of America with which the Commission might confer regarding geological subjects. It was voted to empower the President to appoint three Fellows to act as a Committee on Conservation.* Professor Albrecht Penck, of Berlin, who had been invited by the Council to participate in the meeting, presented a paper entitled “Inter- glacial epochs.” At the close of this paper the special section on correlation withdrew for the continuation of its sessions, and the general section, with Presi- dent Calvin in the chair, proceeded with the main programme. The following two papers were read: GLACIAL WATERS WEST AND SOUTH OF THE ADIRONDACKS BY H. L. FAIRCHILD [Abstract] AS the lobes of the ice-sheet melted away south of the Adirondacks, high- level waters were held in the Schoharie and Mohawk valleys, into which was 1 Later the president (G. K. Gilbert) appointed I. C. White, A. C. Lawson, and E. V. d’Invilliers to serve as this committee. 634 PROCEEDINGS OF THE BALTIMORE MEETING poured the land and glacial drainage of the time, with consequent elevated deltas. The Schoharie lake had outlets to the Hudson and the Delaware, and subsequently the Mohawk waters overflowed southwestward to the Susque- hanna, but finally to the Hudson. The earliest outlet of the Mohawk Valley waters seems to have been by the col at the head of the Otsego-Susquehanna valley, with elevation somewhat under 1,400 feet. A lower escape was found by the Unadilla valley, at about 1,220 feet, and possibly by the Chenango valley at 1,150 feet. Later the out- flow was eastward to the Hudson by Delanson and Altamont and past the face of the Helderberg scarp, at 840 feet as the lowest. The latest flow of the ice- impounded Mohawk waters was south of Amsterdam and past the face of the searp at Rotterdam. The copious drainage of the western slopes of the Adirondacks poured into a lake held in the valley of Black river, with the production or a cemarkable expanse of sand plains. In the various features and relations which charac- terize a glacial lake the Black lake is probably the finest example of a glacial lake in the state (though not nearly so remarkable in complexity of drainage and history as the Genesee waters). The earliest outflow of the differentiated waters of the Black valley was southward past Remsen into the Mohawk lake, with delta built at Trenton and Trenton Falls. The second escape was south- westward, at Boonville, into the inferior Mohawk lake, with delta north of Rome. The third stage had westward outflow, curving around the high ground between the Black valley and the Ontario basin, at Copenhagen and Champion, the flood pouring into lake Iroquois at Adams. CORRELATION OF THE HUDSONIAN AND THE ONTARIAN GLACIER LOBES BY H. L. FAIRCHILD [Abstract] In the waning of the Labradorian ice body the Adirondack massif became uncovered, at first as an island, with probable westward flow of the ice through the Mohawk depression. Later the glacial flow was divided into a Champlain- Hudson lobe and a Saint Lawrence-Ontario lobe. For a long time the Hud- sonian lobe pushed an ice tongue westward into the lower Mohawk valley, while the Ontarian lobe sent one eastward into the upper Mohawk valley. Im- prisoned between the two opposing ice fronts the glacial waters stood at high levels in the Mohawk and Schoharie valleys. As the waning ice margins re- leased successively lower passes to southern drainage the waters fell accord- ingly. The delta sand plains on the flanks of the Adirondacks and in the upper Mohawk valley, with their various declining altitudes, show the successive levels of the waters; and these levels were determined by the positions of the ice margins with reference to a few critical cols or passes on the divide. The two papers were discussed oe by A. P. Brigham, H. L. Fair- child, and A. W. Grabau. PLEISTOCENE GEOLOGY OF THE ADIRONDACKS 635 The next paper was read by title. It was PLEISTOCENE FEATURES IN NORTHERN NEW YORK BY H. L. FAIRCHILD Then the Society listened to the reading of PLEISTOCENE GEOLOGY OF THE SOUTHWESTERN SLOPE OF THE ADIRONDACKS BY WILLIAM J. MILLER! [Abstract] The area discussed in this paper is about 60 miles long and 15 miles wide, and extends from Lowville to Dolgeville, New York. The northern portion of the area is occupied by the Black River valley and the southern portion slopes southward toward the Mohawk river. Some years ago Professor Chamberlin suggested that tongues of ice flowed around the Adirondacks and met in the Mohawk valley.? Observations by the writer along the southwestern Adirondacks have an important bearing upon this question of ice movement in northern New York. In the Black River valley the striz point from south 25° to 40° east and parallel to the strike of the valley, thus showing the influence of the valley in determining the direc- tion of flow. Southward, on the Little Falls sheet, the striz point more nearly east and west, and show a direction of flow parallel to the Mohawk valley. It has already been established that the ice current was southwesterly through the Saint Lawrence valley and southerly through the Champlain valley, and also that an ice tongue moved westerly up the lower Mohawk valley to meet an easterly flowing tongue from the upper Mohawk valley. During the height of glaciation the main ice current was southwesterly across the Adirondack re- gion. This is shown by numerous glacial strive in the midst of the Adiron- dacks and to the south of the Mohawk valley, as well as by the distribution of erratics from the Adirondacks to the south and southwest of the mountains. Bearing in mind all] the facts, the writer is led to the conclusion that when the ice, in its southward movement, struck the Adirondacks, it was divided into two currents flowing around the mountains and meeting in the Mohawk valley; that during maximum glaciation there was a strong southwesterly eurrent, but that border currents continued as undercurrents more or less checked in velocity, and that after the disappearance of the ice-sheet from the central Adirondacks border currents were maintained. There is no evidence to show that ice erosion did any very deep cutting into the pre-Cambrian rocks, but it was much more effective upon the Palezoic sed- iments. The writer believes that in the Black River valley we have one of the best examples of ice erosion in northern New York. Black river follows close to the Paleozoic-pre-Cambrian boundary line, and the Paleozoics, having a thickness of nearly 1,500 feet, overlap upon the pre-Cambrians. On the Port 1 Introduced by W. B. Clark. 2Third Annual Report, U. S. Geological Survey, 1881-2, pp. 360-365. 636 PROCEEDINGS OF THE BALTIMORE MEETING Leyden quadrangle the Paleozoic rocks are distinctly terraced. The steep front of the lowermost terrace rises from 200 to 300 feet, and immediately faces the river. The basal sediments here are weak sandstones and sandy limestones, while the surface of the terrace (Several miles broad) is made up of hard Trenton limestone. Along the western edge of this terrace a second slope (Tug hill) rises over 400 feet within a third of a mile. The base of this slope is made up of the soft Utica shale, while the upper part is made up of the Lorraine sandstone and shale. The steep fronts of the terraces are certainly young topographic features. which preclude the possibility of their having been formed during the long pre-Glacial period of erosion in this very ancient region. On the other hand, little work of erosion has been done in post-Glacial times, as proved by the fact that Black river has not yet cut its way through the recent deposit filling the valley bottom, and also because strie and kames near the river level have not been disturbed. There is still the possibility that glacial waters might have developed the terraces, but there is no evidence for any such vigorous water action, especially along the higher part of the limestone terrace, where records would surely be left. Kames and glacial strise are here left undis- turbed. Evidently the lowest sediments were cut back by the ice to develop the steep slope which now faces Black river. As Robert Bell has suggested for certain Canadian occurrences,? the exposed edges of the sediments resting “on the very hard pre-Cambrians presented the most favorable attitude for ice ero- sion, and they were stripped off the pre-Cambrians until, as Bell says, “the resisting rock front had attained a height and weight sufficient to counter- balance those of the glacier.” In much the same way the steep front of the second terrace was developed by stripping off the soft shales from the hard limestones. The maximum amount of shale thus removed was probably. sev- eral hundred feet, but not over a wide area. Ice erosion was considerably favored by the fact that the ice moved uphill along the valley, and so had its cutting power increased. Another factor of importance was the angle at which the ice current entered the Black River valley in its sweep around the Adiron- dacks. The greatest amount of erosion was along the eastern side of Tug hill, and it was just here where the ice must have struck with greatest force as it crowded into the valley. A remarkable development of glacial sand plains or terraces is to be found within the region here discussed. The greatest sand plain expanse extends from Forestport to an unknown distance north of Lowville, and it has a width of from 5 to 8 miles. This great sand plain has a rather steep front facing Black river, where the deposit is from 200 to 250 feet deep, while it thins out to disappearance eastward. The remarkably concordant altitudes of the plains (from 1,150 to 1,260 feet) ; their crudely stratified character; the general ab- sence of erratics over the surfaces, and their frequently lobate character all argue conclusively for their origin as delta deposits which were formed in a marginal lake along the waning ice during its retreat from the higher to the lower land along the western Adirondacks. Another fine but smaller sand plain covers about fifty square miles between West Canada and Black creeks (Remsen sheet). A thick bed of clay underlies this sand, and the sand was * Bulletin of the Geological Society of America, vol. 1, 1890, p. 296. PLEISTOCENE GEOLOGY OF THE ADIRONDACKS 637 evidently pushed out as a delta deposit after the deposition of the clay. A number of good examples of smaller sand plains also occur, and all have had a similar origin. Of the glacial lakes the most interesting and extensive one occupied all of the sand flat country from Forestport to north of Lowville. The former pres- ence of this large lake is shown by the great development of unquestioned delta deposits above referred to. These waters were impounded by a waning lobe of ice in the Black River valley. The kames and drift boulders along the western edge of the terraces in the valley show an ice-contact front there. Also the absence of delta deposits on the west side of the river, under Tug hill, . shows that the lake did not extend that far west. The failure of any delta deposit to reach out to or across the valley bottom argues for ice occupancy of the deepest part of the valley during the existence of the large lake. The high- . est water level was apparently something over 1,300 feet (using present eleva- tions) at which time an outlet probably crossed the Black River-West Canada Creek divide near Honnedaga, and flowed southward toward Trenton Falls. Further melting of the ice lobe certainly opened an outlet past Boonville and down Lansing Kill (creek) toward Rome. The pre-Glacial divide was doubt- less near Hurlbutville, as shown by the widening of the channel, both north- ward and southward, from that place; by the existence there of a deep inner gorge; by the aggraded stream bottom north of Hurlbutville; by the fact that the present stream could not have cut the deep, narrow channel there, and by the right elevation of an outlet there. The lake stood at about the 1,250-foot level when it started over this divide, and it cut down the divide rapidly until the 1,140-foot level was reached. By this time the ice had so far melted as to allow an escape of the water northerly and northwesterly along the western side of the ice tongue and into lake Iroquois. Another lower and very distinct lake level was a little below 800 feet, and caused by still further ice retreat to allow an accumulation of water back of a barrier at Carthage. This lake ex- tended southward to Lyons Falls, where it was very narrow. Between Lyons Falls and Carthage the winding stream is now cutting terraces through the old lake deposit. The glacial lake which extended over the sand flat area between West Canada and Black creeks (above mentioned) stood for some time at or near the 1,400-foot level, and during part of the time, at least, may have had an outlet through the Spruce Creek channel. Many fine kames have been found within the region, their greatest develop- ment being in the vicinity of Hinckley (Remsen sheet), where they form kame- morainic ridges with the typical knob and kettle structure. An interesting feature is the occurrence of partially buried kames, which are particularly well shown in the vicinity of Forestport (Remsen sheet). After the forma- tion of the kames and the withdrawal of the ice, the delta sands were built around the kames to partially bury them. In this way many kames were doubtless completely buried, as must have been the case where the sands are so deep in the Port Leyden region. The paper was discussed by G. K. Gilbert and Albrecht Penck, 638 PROCEEDINGS OF THE BALTIMORE MEETING Then was read WEATHERING AND EROSION AS TIME MEASURES BY FRANK LEVERETT [Abstract] The paper set forth the use that may be made of weathering and erosion in determining relative age of the several drift sheets. It also dealt with the most important qualifying conditions that affect estimates. At the close of the reading of this paper, at 12.30 o’clock, adjourn- ment was taken, discussion being postponed to the afternoon. The Society convened again at 2 o’clock, President Calvin presiding, and took up the discussion of Mr Leverett’s paper, the participants being A. Penck, 8. Calvin, F. Leverett, G. F. Wright, and G. K. Gilbert. The next two papers were then read: GLACIAL PHENOMENA OF SOUTHEASTERN WISCONSIN BY WILLIAM C. ALDEN* [Abstract] A graphic presentation by a map 9 by 10 feet, scale 1 mile per inch, of a detailed study of the deposits of the Green Bay and Lake Michigan glaciers and associated phenomena of late Wisconsin glaciation of southeastern Wisconsin. The map represents an area approximately 8,600 square miles, which has been studied by the author under the direction of Dr T. C. Chamberlin during the greater part of the last ten years. The presentation comprised such de- scription as the time permitted of the conditions affecting the advance of the two glaciers, their relations to each other, the character, distribution, and mode of formation of the several deposits, terminal and recessional moraines, out- wash deposits, ground moraines, drumlins and eskers, the lithological composi- tion of the drift and its significance. Evidence was presented by a deposit of red till of a later readvance of the two glaciers southward to the vicinities of Milwaukee and Fond du Lac. The shorelines and deposits of lake Chicago and succeeding glacial lakes were also shown. CRITERIA FOR DISCRIMINATION OF THE AGE OF GLACIAL DRIFT SHEETS AS MODIFIED BY TOPOGRAPHIC SITUATION AND DRAINAGE RELATIONS BY WILLIAM C. ALDEN? [Abstract] The discussion was confined to phases illustrated by the pre-Wisconsin drift of southern Wisconsin and northern Illinois. 1 Introduced by T. C. Chamberlin. DISCRIMINATION OF AGE OF GLACIAL DRIFT SHEETS 639 Character of this drift and reasons for regarding the drift exposed at the surface throughout this area as belonging to one and the same sheet. The lithological composition and its significance, directions of ice movement, ab- sence of intercalated weathered zones, soils, or vegetable deposits. Differences in the apparent amounts of surface modification of this drift in different parts of the area which might be regarded as indicating differences in age: 1. Topographic relations and amount of erosion. 2. Weathering, leaching, and oxidation. The occurrence in places of thor- oughly disintegrated drift or residual till; in others, of drift but moderately leached and oxidized ; in others, of perfectly fresh unmodified drift at the sur- face or immediately below the loess. The reasons for these differences : 1. Influence of pre-Glacial topography on drainage slope and upland of the drift. Influence of the Saint Peter sandstone on the pre-Glacial topography. Relations of surface wash to the apparent amount of surficial leaching and oxidation. 2. The post-Illinoisan diversion of Rock river below Rockford, Illinois, and the consequent retardation of erosion due to the work of cutting new rock gorges at several cols. Removal of the weathered drift from slopes with preservation on the uplands. Necessity for caution in the discrimination of distant drift sheets in the ab- sence of marked differences in lithological composition or of sections showing overlapping drift with intercalated soils, vegetable deposits, or weathered zones. The two papers together were discussed by F. Leverett. Then was read ; LAKE OJIBWA, LAST OF THE GREAT GLACIAL LAKES BY A. P. COLEMAN [Abstract] As the Labrador ice-sheet retreated north to the watershed between the Great lakes and James bay, the waters now flowing northward were impounded, first as a narrow bay of lake Algonquin opening south past Sudbury, after- wards as a Separate lake with an outlet down the Ottawa valley. This lake probably existed during the time of the Nipissing Great lakes, and was the last of the ice-dammed lakes. The elevation of its outlet is now 900 feet, but was then much lower. In its bed the “clay belt” of northern Ontario and Quebec was deposited, having an extent of over 25,000 square miles. The maximum area covered by its waters must have been greater than that of lake Superior ; though probably its extent varied greatly in accordance with the position of the ice front. ; This paper was discussed by F. B. Taylor and A. P. Coleman. LXI—BULL. Gnou. Soc. AM., Vou. 20, 1908 640 PROCEEDINGS OF THE BALTIMORE MEETING The next paper read was GLACIAL EROSION ON KELLEYS ISLAND, OHIO} BY FRANK CARNEY Contents Page InNtroGuction : is 5 ice iets cee ae ne 8 6 6 wie 3 oe ste ailw Oo tone) oy opone dele ele Sisters tele eens ee eae 640 Discussion ..... ei 6b Boe © 0 6 6 50.6 6 Weis sie a ae wm wise UMSTige all eqs Ciieike eee Neh ele lik Sasieen earn 641 Direction of ice motion:.,....... 6 520 see ee & bee cele ewe Bleue) oe chee ce ee 643 TNHERGECDPSLOOVES 2.5 \-15 ee S acess Byaveqareteke er oeaieneiee cg-s.s\e bs eels S418 miele nie SH it Ree 644 SUMMATLY 8.5.56. ee be ak ee wesw cle lee ey te ee el cue tenes ereete eee ene 645 INTRODUCTION All are familiar with the conventional cross-section of a valley deepened by glacial erosion. This paper aims to show (1) that wherever we have concen- trated glacial erosion in rock, the result, whether a groove a few inches deep or a modified valley over-deepened several hundred feet, is a U-profile; (2) that the grooves on Kelleys island were cut in a very short time; that the tools were largely of limestone of the formation being eroded, and that the work was done not long before the ice melted back permanently from the island. This island is located about 6 miles off the mainland. Its area is approxi- mately 7 square miles, and it lies north of the axis of the Lake Hrie ice lobe. Its surface consists of limestone bearing a slight veneer of glacial drift. Locally the drift has been assorted by wave action of the lake at a higher level, leaving beach gravels at the foot of the cliffs cut in the limestone. The region has long been known for its quarries as well as for its unusual glacial erosion features. At the present time there are three principal work- ings, designated the North, West, and South quarries (figure 1), operated by the Kelley Island Stone and Transport Company. Between the West and the South quarries, during the past summer, an area about 100 rods long and 4 rods wide was stripped preparatory to opening up a new quarry. This surface, which lies transverse to the direction of ice motion, was covered by from 3 to 6 feet of glacial drift. This recently exposed area of limestone presents features of ice work which, when considered in connection with the scoring and grooving near by on the island, suggest some interesting questions in glacial erosion. The area represented in figure 1, plate 108, looks northward over the area, which up to a point in the distance where the rock surface appreciably rises is completely smoothed and striated (figure 2, plate 108), presenting, for the most part, a perfectly flat surface. Toward the north end, however, is a depression in this otherwise flat expanse; a few rods beyond this depression the glaciated surface is displaced by a rising slope of limestone which shows no evidence whatever of ice work. Furthermore, the camera stands on rough limestone that does not give the slightest indication of ice erosion. The smoothly polished area intervening is 880 feet long. A little more than three 1 Presented with the permission of the Ohio Geological Survey, it being understood that the author is responsible for the opinions expressed. Manuscript received by the Secretary of the Society on February 24, 1909. 2 My attention was called to this new exposure by Mr C. R. Stauffer, BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 108 FIGURE 1.—SURFACE ON KELLEYS ISLAND RECENTLY STRIPPED FOR QUARRYING emi a FIGURE 2,.-DETAIL OF THE GLACIAL SCORING ON THE RECENTLY STRIPPED AREA, LOOKING WEST (C. R. STAUFFER, PHOTOGRAPHER) GLACIAL PHENOMENA ON KELLEYS ISLAND GLACIAL EROSION ON KELLEYS ISLAND 641 quarters of a mile north is located the deeply grooved limestone that is classic among the better known areas of glaciation;? these grooves (figure 1, plate 109) are quite regular in horizontal extension; their original length is not known because of partial obliteration by quarrying. The details of this grooving will be considered later. Northward from the area under discussion the limestone at the West quarry also shows plainly the work of ice, but not in the marked degree seen at the North quarry; the rock is scored and striated and contains some shallow grooves. The drift on the island wherever exposed consists almost entirely of clay and of limestone blocks. In several exposures, studied closely, erratics were rare. FIGURE 1.—Kelleys Island, Ohio The South quarry is indicated by S; the North quarry by N; the recently stripped area by X. DISCUSSION A north-south section of the island through the areas above described shows a striking variation in the intensity of ice erosion. Not only does its intensity vary from place to place, but the change is abrupt. A surface of uneven and 3G. K. Gilbert: Surface geology of the Maumee valley. Geological Survey of Ohio, Oil, 3k, aleshyals joy txsise T. C. Chamberlin: Seventh Annual Report, U. S. Geological Survey, 1885, pp. 211-216. G. F. Wright: Ice age in North America, 1889, pp. 232-238. 642 PROCEEDINGS OF THE BALTIMORE MEETING unpolished limestone might be due to the effects of weathering in post-Glacial times. In localities where the drift is very thin and freezing in consequence had penetrated the rock, the irregular condition of the limestone may repre- sent normal disintegration ; some of the rough surfaces observed might be thus accounted for. In the area recently stripped, however, the depth of the drift precludes this explanation. So far as it is possible to tell, the area over almost its entire length was protected by a uniform mantle of debris. This sudden transition from polished to irregular and rough surfaces can not be accounted for by the effects of post-Glacial weathering. Fickleness in the abrasion work of glacier ice is an old observation. Sur- faces which lithologically should register the striations of rock-shod ice are frequently without this evidence; several miles of such outcrops are known. But when ice passes over limestone horizons we expect to find it registering the slightest work of tools carried in its basal area; where such horizons have been protected from weathering during post-Glacial time by drift, even the weak striz should now be seen. Irregularity in the intensity of glacial scoring, or even its presence and absence over long distances, is not remarkable. But when this variation is found within a mile it arouses our interest; further- more, when the variation is so striking, as is the case on Kelleys island, we would seek an explanation. For several square miles about Sandusky limestone outcrops. The numerous islands in this region are evidence of pre-Glacial stream erosion topography, modified to some extent by ice work.* This irregular surface lies apparently not far from the axis of the Erie basin, and therefore has the proper exposure for inviting active ice erosion. On Marblehead, at least, it was observed that the major joint planes are but slightly discordant with the direction of the moving ice (figure 2, plate 109). Under these conditions it is apparent that locally the basal parts of an ice-sheet might be overloaded even to the point of becoming stagnant.. Such a mass of stationary ice would interfere with the movement of the ice immediately in its rear. At first this coming ice would be checked, but later it would move upward, shearing across the stagnant area. As the overloaded mass gradually lost velocity, the zone of ice directly above it moved onward or sheared over it; the ice in the rear on moving upward proceeded with this ice. The weight of the superincumbent mass would account for a downward movement on the leeward side of the stagnant area. If this downward moving line of ice were properly shod with debris, the rock surface beneath it would suffer unusual erosion; thus the surface on the leeward side of a stagnant area under these conditions would be strongly glaciated.® An overloaded mass of ice loses its velocity gradually, for it acquires its load gradually; in consequence of this the rock surface covered as the mass reaches the stage of stagnation does not suffer further abrasion, at least not until after this stagnant mass has been removed, probably through being grad- 4J. S. Newberry says: ‘They are all wrought by glacial action.’’ Geological Survey of Ohio, vol. i, 1873, p. 111. 5 Chamberlin and Salisbury: Geology, vol. i, 1904, p. 271. 6 Chamberlin, in discussing the ‘‘Removal of scoring debris from action,’”’ mentions that in the opinion of some glacialists there may be an ‘‘upward movement through the body of the glaciers.”” Seventh Annual Report, U. S. Geological Survey, 1885, p. 239, Chamberlin and Salisbury : Loc. cit., p. 282. BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 109 . FIGURE 1.—GENERAL VIEW OF A GROOVED SURFACE OF KELLEYS ISLAND FIGURE 2.—GLACIAL CORRASION ON MARBLEHEAD PENINSULA, SUGGESTING A RELATION- SHIP TO MAJOR JOINT PLAINS GLACIAL PHENOMENA ON KELLEYS ISLAND a GLACIAL EROSION ON KELLEYS ISLAND 643 ‘ually pared off along the shearing planes developed over its surface. It is possible that in the course of time these shearing surfaces may be so lowered as to gradually carry away the entire mass of stagnant ice. During the period of stagnation the surface immediately covered was protected from further ice action. In accordance with the above discussion, this surface could not have been much scored in the process of overloading; but previously it may have been striated. Furthermore, it is possible that the gliding surface once estab- lished may persist, and the overloaded mass ‘become, in effect, a part of the bed over which the glacier continues to move. So far we have discussed only the conditions observed in a longitudinal cross-section of the ice. The basal ice on either side of this overloaded lens. immediately contiguous, lost velocity; here, too, shearing planes were devel- | oped, and the ice laterally moved with the general basal trend. If this ice were properly shod with rock, the surface beneath it would suffer abrasion; so under these conditions there might be an area on all sides of which the rock surface has been smoothed and striated. Remembering, however, that debris in an ice-sheet is not apt to be homogeneously distributed, such general erosion is seldom the case. As the ice may carry 4 plentiful supply of tools in a narrow longitudinal band at its base, and adjacent to this band be relatively free of rubbish, we might find just such a relation of surfaces as are shown in figure 1, plate 108. The fact, however, that glacially scored surfaces are interrupted in the line of ice motion by unscored surfaces gives much significance to the theory of up- ward and downward movement of currents within the ice-mass. We have long known that the erosive york of rivers is accomplished largely by such secondary currents, which are accessory to the main flow of the river. It seems not unreasonable that in an ice-sheet there may exist similar secondary currents, occasioned also by irregular topography, and that when these lines of accentuated flowage bear a reasonable amount of tools they may do unusual erosive work. DIRECTION OF IcE MOTION Data on the direction of ice motion in this region was collected on Marble- head, on Kelleys island, and on Point Pelee island, about 10 miles north of Kelleys island. For part of this information I am indebted to Mr C. R. Stauffer. In the first area the irregular channels shown in figure 2, plate 109, read south 76 degrees west, conforming with the general direction of the major joints. On Kelleys island, at the North quarry, the grooves read south 73 degrees west. At the recently stripped area south of this quarry two sets of striz are conspicuous, the older varying from 1 degree to 8 degrees south of west, with very many east-west readings, while the latest ice movement varies from 23 degrees north to 23 degrees south of west; thus there is some divergence in both the older and more recent direction of ice motion.”. At the West quarry the general direction of striz is south 75 degrees west. A surface between the 7F. Leverett gives readings of other striated areas in this part of Ohio. Monograph XLI, U. S. Geological Survey, 1902, pp. 423-424, 644 PROCEEDINGS OF THE BALTIMORE MEETING West and South quarries bears strize reading south 60 degrees west; these are intersected by lines south 85 degrees west. On Point Pelee island the older sets range about south 60 degrees west, while the more recent are east-west. Perhaps neither of these two sets of strie represents the movement of the general ice-sheet during either the advancing or the maximum Stage; it is more probable that all this scoring is the work of the glacier after it has ceased to advance. Whatever grooving and polishing had been accomplished by the ice at earlier stages was either modified or obliterated by the action of the Erie Lobe stage, when the Erie basin was occupied by a deploying lobe of ice. In this area, then, constancy in direction of strize would be found only along or very near the axis of the lobe. Laterally from this axis the earlier set would be more generally east-west, but as the front of the ice successively took new positions the last movement over a given place off the axis was out- ward from the axis, thus imposing on the east-west set striz trending to the north or to the south. The Erie lobe was associated with ice from the Labrador dispersion center. The general motion of the ice through this basin should, therefore, be south of west. The fact that we have some readings north of west, and many readings more nearly east-west, indicates that the Erie Lobe axis was a little south of Kelleys island. On this supposition, then, the east- west readings and those approximately east-west represent the more general motion of the Erie lobe, whereas the other readings are due to the deployment at a later stage. The more vigorous scoring, particularly the grooves, shows less diversion from the east-west line. i: Some of the surfaces from which these readings were taken are so com- pletely covered with very fine scratches that one can not state with absolute certainty the order in which the striz were made. THE DEEP GROOVES A cross-section of this grooved surface (figure 1, plate 109) is a half-oval figure. The apex drops off into the quarry; therefore the original shape of the cross-section can not be given. The outline preserved suggests somewhat the roche moutonnée type of erosion surface. The prevailing cross-section of the individual grooves is U-shaped. The grooves are sharply defined, almost mechanically precise in outlines. The north side of one of the grooves overhangs. On all of the surfaces, both in the grooves and on the areas between the grooves, are delicate striz, with only now and then a harsher line. There is very little evidence of chatter abrasion, and only one conspicuous gouge was noted. Plate 110 shows an area where the tools diverged from the straight line and produced a fluting effect; the rock surface around which the tools moved appears no harder than the rock elsewhere. A simple explanation for these great grooves, one that is not uncommonly siven, is to account for them by the lathe-like effect of the large boulders held in the bottom of the ice. A closer analysis, however, leads to the following conclusions: (1) The vigorous scoring indicates a localization of tools and a constant supply of them in the basal area of the ice; the source of this supply BULL. GEOL. SOC. AM. VOLE. 20,5) 11908; PES do BULGING IN A GROOVED SURFACE ON KELLEYS ISLAND, OHIO By GLACIAL EROSION ON KELLEYS ISLAND 645 evidently was near at hand, for the sharp-cut details of striation indicate freshness of the tools; (2) the country rock is not appreciably harder than the tools used in carving it; this conclusion is arrived at partly because of the absence of ecrystallines in the neighboring drift, also because tools secured from a more distant source probably would have suffered much from abrasion in transit, thus losing the sharper outlines and becoming less liable to produce the accurately defined striz above described; furthermore, there is positive evidence in the drift that the local limestone was the chief source of the debris; (3) these grooves indicate a concentration of erosive processes within a narrow limit, or, better, a Superimposed alignment of striz, causing at first a depression below the general level of the rock surface; (4) the basal ice under pressure moulded itself to the slight depression thus made; in conse-_ quence there was further localization of mechanical work. That the ice con- tinued to fit the grooves as they were deepened is shown in the fact that the sides of the grooves are delicately striated, and in the further fact that in one groove at least there was such a continued supply of tools as to cut the wall back farther and farther, producing an overhanging condition. All parts of this overhanging wall are striated. SUMMARY Cumulative observation has shown (1) that glacier ice, of either the conti- nental or alpine type, when moulded to or confined within a valley, changes its subaerial and water-erosion profile to a U-shaped cross-section; (2) that this ice continuing to occupy such a valley is competent to overdeepen it hundreds of feet. The grooves on Kelleys island show that when tools are so localized in the basal ice as to abrade continuously within a narrow limit, say a few inches, the result shortly is a shallow elliptical depression, and, later, the action con- tinuing to be localized, a U-shaped trough, which may become deeper than broad. The weight of the ice mass keeps it moulded to the growing groove, which is enlarged so long as cutting tools, even grains of sand, are present. This behavior of ice is Somewhat analogous to the response of a plastic sub- stance under pressure; in consequence the tools grind and scour laterally as well as on the bottom of the groove. When ice feeds alpine-like through a valley, or when the movement of an ice cap trends with a valley, overdeepen- ing will inevitably follow if the ice carries tools in contact with the valley walls. The paper was discussed by G. F. Wright. Then was read CHALK FORMATIONS OF NORTHEAST TEXAS BY C. H. GORDON [Abstract] Extending in a west to east direction across the southern part of Lamar county, and thence northeast through Red River county to Red river, and hav- ing a width of from 1 to 3 miles, is a belt of chalk known as the Annona chalk, from the town in Red River county near which it outcrops. In the earlier pub- 646 PROCEEDINGS OF THE BALTIMORE MEETING lications relating to the Cretaceous of Texas this formation was considered as the diminished representative of the Austin chalk of central Texas. Later authors, however, have contended that it represents a higher horizon, and be- longs within the so-called Navarro division of the Upper Cretaceous. Recent investigations by the author, in connection with the study of the underground waters of northeastern Texas, tend to confirm the earlier view as advanced by Taff that the Annona is the northeastward extension of the Austin formation. Tracing the outcrop of the Annona westward, it was found to merge with that of the Austin as exposed in the vicinity of Honey Grove and westward to Sherman. At Austin the formation has a reported thickness of about 600 feet, and is composed essentially of chalk throughout. 'Toward the northeast the lower beds become marly, the thickness of the chalk marl in- creasing until in the vicinity of Red river the marls have a thickness of about 400 feet. To this part of the formation, as represented in northeastern Texas and southwestern Arkansas, Hill applied the name Brownstown beds. The relations seem to indicate that at the beginning of the Austin epoch the conditions for the formation of pure chalk existed only in the region about Austin, but with the progress of time they were extended farther and farther northeast as a result possibly of a change in the relative position of land and sea. The next paper was read by title: GEOLOGIC HISTORY OF THE OUACHITA REGION BY E. 0. ULRICH After which was read RESULTS OF A RECENT INVESTIGATION OF THE COASTAL PLAIN FORMATIONS IN THE AREA BETWHEN MASSACHUSETTS AND NORTH CAROLINA! BY WILLIAM BULLOCK CLARK [Abstract] Contents Page General’ characteristics of the formations. <2... sees cs) + =e 2 =e) oie) ieee eee 647 CLSTACEOUS. ¥ateleci5 ed oe leek ete os tose Scale aia to SU uae We bie WSO NG ES delle et oneiatelsle Ghats leone - 647 Bower Cretaceous! \ oc 6 cesses a eee a biel s «lela eveel aera eae Silenede 4 le «le uals Se 647 WP Per (CREEACCOUS ae. 6: ove iee eee fate olin ie cg sine: © &,seriens els tote lal 616 :leie ove eipetre/felseie ete eee 647 Table of Cretaceous formations. 26.5... 6.6 see ee ce wre © ore eee ene) eee eee 648 MM OTEVATNY, oie sanetjencaarenetoo. ace ienalomene te wurerie Bs otaisa' 's alee ei’ei'e elie. Orehd) os) eleveieuenete elelons peel eee 649 FO CONC 65:6. ocd wets oe ete te wie leun'eviouslele lave ettece.e. oBP S000. Scacene ea le leg telete lake: Gkenet: totam meme 649 MIOCENE: ceislacee Scie ie, ois eleva ene wiciloreils o 6. gies else & iecane, eliore Whee tole to, oitel oR nee ene aan 649 PITO CONIC foc .eis eis roceeis neato vo see. oi aida co: © Bio vd cose elas se: fen -bise. fo’ a falas OU ota detaPe re one apenas OMey ole eat aan 649 Table of Tertiary formations: ....)..4 405 os oe on eee ected ble neuen eee 650 Qwaite km a rye eeu tee Premieres 7a eee cnive a/e otets wcele oeae ‘eis belie 66 see 6 suetelei meee 650 PLEISTOCENE... sickle cide ole eles onbid elects sacle e dim miw w lecereierie @) slale (6) 5) t aee On eee 650 FROCONG oie oi oer eo rare eieresese eb. 05 eR avn ole jane ore dal ebanelieyleto HONORE ne Henne nee 651 Comparison of the Atlantic Coast formations with those of the Gulf and other areas 651 1 Published by permission of the Director of the U. S. Geological Survey. Messrs B. L. Miller, L. W. Stephenson, BH. W. Berry, and A. B. Bibbins and Miss J. A. Gardner have been associated with the author in this work. Manuscript received by the Secretary of the Society May 26, 1909, LL. GEOL. SOC. AM. NEW JERSE COLUMBIA LONG ISLAND AND SO, NEW ENGLAND =RNARY | RANCOCAS MONMOUTH RTIARY TAWAN GOTHY MAGOTHY |= ARITAN RARITAN COMPARAT BULL. GEOL. SOC. AM. VOL. 20, 1908, PL. 111 ALABAMA DELAWARE—MARYLAND COLUMBIA LAFAY! RIPLEY, INeLUDING BrLMa NEW JERSEY coLuMBIA [250] LONG ISLAND AND SO, NEW ENGLAND EUTAW INCLUDING ToMBgSrE JATERNARY. TERTIARY TUSCALOOSA wo ALA MATAWAN MAGOTHY TUSCALOOSA PATUXENT RARITAN ALA, AnD GA. COMPARATIVE COLUMNAR SECTIONS OF ATLANTIC COASTAL PLAIN FORMATIONS ” : iad PMMADS A HI wT Ae ae a eG Ea ‘e Sag 7 eat se ay hip td tN hy Saat meyenel= ARSAD NSAI TEMAS JATAROS GITHAITA 8D EROITE RECENT INVESTIGATION OF COASTAL PLAIN FORMATIONS 647 GENERAL CHARACTERISTICS OF THE FORMATIONS The progress of the investigation of the formations of the middle and north- ern Atlantic Coastal Plain region furnishes little by little a clearer interpreta- tion of the geology of that area. The deposits as a whole have been but little changed since they were originally laid down along the coastal border, but the strata present much complexity due to the variation in the angle and direction of tilting during the successive oscillations of the sea floor. The sediments in general form a series of thin sheets which are inclined seaward, so that suc- cessively later formations are encountered in passing from the inland border of the region toward the coast, yet at no place accessible to our study do we find a complete sequence of deposits, although sedimentation must have been continuous over a large part of the continental shelf. The incompleteness, therefore, must be regarded as a purely marginal condition due to the trans- gressions and retrogressions of the sea along the coastal border. The correlation table given on the accompanying plate shows the relations of the several formations throughout the northern and middle Atlantic Coastal plain and their approximate equivalents in the eastern Gulf region. CRETACEOUS The Cretaceous formations constitute the basal deposits of the Coastal Plain series along the line of outcrop. Well borings throughout the district have not afforded strata of earlier age, although they may exist to the eastward toward the margin of the continental shelf. LOWER CRETACEOUS Deposits of Lower Cretaceous age are most extensively developed in Mary- land and northern Virginia, where the Patuxent (arkosiec sands, gravels, clays), Arundel (clays, lignites, carbonate of iron concretions), and Patapsco (varie- gated clays, sands) formations occur. The organic remains consist for the most part of dinosaurs and plants. Lull, who has recently studied the former, and Berry, who has been engaged in an investigation of the latter, are agreed that they are of Lower Cretaceous age, so that the earlier questionable refer- ence of the Patuxent and Arundel formations to the Jurassic is now abandoned. Farther southward in North Carolina is the Cape Fear formation (arkosic sands, clays), so called by Stephenson, which is evidently continuous with the Patuxent formation, although the basal beds of the Coastal plain are trans- gressed by later formations in southern Virginia and northern North Carolina. No fossils have been found in the Cape Fear formation, but the strata are sim- ilar lithologically to the Patuxent farther north and unlike the Arundel and Patapsco. UPPER CRETACEOUS Upper Cretaceous deposits extend from New Jersey, where they are most ex- tensively developed, northeastward along the New England coast and south- ward through Delaware and Maryland to the Potomac valley. Strata of this age have been penetrated in well borings in eastern Virginia, but do not appear along the line of outcrop, being overlapped by Tertiary formations. In North Carolina Upper Cretaceous deposits again appear, and cover a wide area to the south of the Hatteras axis. 648 PROCEEDINGS OF THE BALTIMORE MEETING The Raritan formation (clays, sands, gravels) of the northern part of the Coastal plain evidently represents the earliest phase of Upper Cretaceous depo- sition, these beds overlying the Lower Cretaceous strata, where exposed, with a marked unconformity. Beds of similar age do not occur in North Carolina. The overlying Magothy-Matawan formations (sands, clays, lignitic and glau- conitic beds), which outcrop throughout the area from the Potomac basin northward to the islands off the New England coast, are represented in North Carolina by the Black Creek formation (sands, clays, lignitic and glauconitie beds), the same fauna and flora characterizing the deposits in both areas. The minor subdivisions established in New Jersey, where these formations are best developed, can not be recognized elsewhere, and the changes in physical condi- tions bringing about the differentiation of faunules there described were evi- dently only local. The Monmouth formation (glauconitic beds, sands, clays) characterized by the introduction of Belemnitella americana and other forms can be traced through New Jersey. Delaware, and Maryland, and again reappears in North Carolina, the deposits here and in South Carolina having been named the Peedee formation (glauconitic beds, sands, clays). The reappearance of one of the earlier faunules toward the close of the Monmouth, as observed in New Jersey, is wanting. The Rancocas and Manasquan formations (glauconitic and calcareous beds) of the northern part of the Coastal plain are chiefly found in New Jersey and Delaware, and contain a younger fauna. Such late Cretaceous strata are not known elsewhere along the Atlantic border. TABLE OF CRETACEOUS FORMATIONS Long Island 7 | and southern | New Jersey Deleeare ay | Virginia North Carolina) Alabama New England ~ Manasquan | x | Ranecocas Rancoecas n } } 5 | 3 Monmouth | Monmouth | |” Peedee | Ripley : a rm | = | . | Matawan Matawan Matawan | Ruan ay |S] Black Creek S) |} Z Tuscaloosa Magothy Magothy Magothy (West Ala.) | Raritan Raritan Raritan | 2 2 Patapsco | Patapsco S) & —_—_${$S{=====——_—_——— |) a ae en = Arundel s | oT | e | Patuxent | Patuxent Cape Fear | (ge RECENT INVESTIGATION OF COASTAL PLAIN FORMATIONS 649) TERTIARY RELATION OF TERTIARY TO CRETACEOUS FORMATIONS The Tertiary formations overlie the Cretaceous formations unconformably, and at times transgress them, the Tertiary strata in such instances resting directly on the crystalline rocks of the Piedmont plateau. EOCENE The Eocene deposits of New Jersey, known as the Shark River formation (glauconitic beds), apparently overlie the Manasquan formation conformably. The contained fossils show the beds to be of early Eocene age. Farther south in Maryland and Virginia, but nowhere in contact with the Shark River beds, is a Series of younger and conformable Hocene deposits known as the Aquia and Nanjemoy formations (glauconitic beds, clays, sands), which overlie the Cre- taceous unconformably. Entirely discontinuous are the North Carolina Hocene strata, which Miller has named the Trent and Castle Hayne formations (ealea- reous marls, clays), and which are of still later Eocene age. The latter are apparently unconformable to each other, and likewise rest unconformably on Cretaceous deposits. MIOCENH The Miocene deposits are best developed in the Chesapeake Bay region, where four formations have been recognized, known as the Calvert (clays, sandy clays, diatomaceous earth, shell marls), the Choptank (sandy clays, sands, shell marls), the St. Mary’s (sandy clays, sands, shell marls), and the York- town (fragmental shell marls, sandy clays, sands). The Choptank does not occur in Virginia, and the Yorktown is absent in Maryand. These formations are evidently continued in part into New Jersey, as similar faunas have been found there, but the relationships have not been fully worked out as yet. To the southward the St. Mary’s and Yorktown formations, transgressing the ear- lier deposits, continue on into North Carolina, both being found over extensive areas to the north of the Hatteras axis, where the Yorktown overlies the St. Mary’s unconformably. To the south of the Hatteras axis deposits very similar to the Yorktown formation, both lithologically and paleontologically, but known under the name of the Duplin formation, are found resting unconformably on pre-Miocene formations. PLIOCENE The Pliocene deposits are of two types: (a) the marine beds, called the Wac- -eamaw formation (clays, sands, shell marls), and confined to a narrow belt on the eastern margin of the Coastal plain of North Carolina; (6) the terrace de- posits found along the higher portions of the Coastal plain, and known as the Lafayette formation (gravels, sands, loams). The terrace is more dissected than the later Pleistocene terraces. The Lafayette formation is most exten- Sively developed in Maryland and Virginia. In Delaware and Pennsylvania on the north and North Carolina on the south it is very fragmentary. 650 PROCEEDINGS OF THE BALTIMORE MEETING TABLE OF TERTIARY FORMATIONS Maryland Virginia | North Carolina g f Lafayette Lafayette | Lafayette 5 | < | a | Waccamaw WE dees SU ae Yorktown | Yorktown and Duplin 2 St. Mary’s St. Mary's | - St. Mary’s S Ie nae een nae gre PRE we ae ONE | ERT Oe = | s Choptank | Calvert Calvert ; Castle Hayne ® Trent 5 : Oo } Nanjemoy Nanjemoy Aquia Aquia QUATERNARY The Quaternary deposits overlie the older Coastal Plain formations as a sur- ficial cover, and embrace a large part of the country from the Piedmont border to the coastal margin. They represent the most recent phase of deposition, and still preserve largely their original form. Physiographic criteria, therefore, are of much importance in interpreting and correlating the deposits. PLEISTOCENE The Pleistocene deposits consist chiefly of a series of terraces, the earliest found along the western border of the Coastal plain, encircling the margin of the Piedmont plateau and the higher elevations of the Coastal plain, and ex- tending up the estuaries and streams, where it finally merges into fluviatile deposits. This oldest terrace, known as the Sunderland formation, can be traced from the glacial deposits southward across Maryland and Virginia into North Carolina. The Sunderland terrace, which has an elevation of 150 to 200 feet along its shoreward margin, declines gradually seaward and toward the larger valleys, where it reaches to below 100 feet in height. Another terrace is found in central and southern North Carolina between the Lafayette and Sunderland. The next younger terrace, known as the Wicomico, encircles the preceding terrace at a lower elevation, and forms a well marked belt along the eastward margin of the latter, although extending up the river channels in some places to the Piedmont border, where it also merges into fluvatile deposits. Its land- ward margin has an elevation of 80 to 110 feet, from which point it declines seaward and toward the larger stream valleys to 50 to 60 feet in elevation. Its RECENT INVESTIGATION OF COASTAL PLAIN FORMATIONS 651 surface is not as extensively dissected as the Sunderland terrace, and near its inner margin are found many buried valleys that were cut at the close of Sun- derland time. Below the Wicomico terrace, and encircling it, is the third or youngest ter- race of the Pleistocene, which has been called the Talbot. The landward mar- gin of the Talbot terrace is from 40 to 60 feet in height, from which elevation it gradually declines seaward until it reaches nearly, if not quite, to sealevel. The Talbot terrace has been but slightly dissected, compared with the earlier terraces, and forms the coastal lowlands. It may also be traced as a low ter- race far up the estuaries and river valleys until it also merges into true fiuvia- tile deposits. In North Carolina it divides into two terraces, constituting the Chowan and Pamlico formations. All of these Pleistocene formations have been traced step by step throughout the area in question, and present the same general characters everywhere. RECENT The Recent deposits consist of beaches, sand bars, sand spits, sand dunes, flood plains, and other fluviatile deposits and humus. These deposits represent the results of all the geological agencies now at work in modifying the surface of the Coastal plain, and are variously developed in the different portions of the region, dependent on the character of the adjacent formations and the dis- tribution of the various streams and currents. A great Recent terrace, similar in all particulars to those of Pleistocene date, is now being laid:down beneath the bed of the present sea and estuaries and along the border of the coast and tidal streams. Beaches are frequently being formed, while great sand bars are common. Sand dunes adjoin the coast, and are especially prominent in south- ern Virginia and North Carolina, where from cape Henry southward they are a conspicuous feature of the coastal topography. The rivers during flood are constructing flood plains, which coalesce with the deposits of the estuaries. Over the land surface the transfer of material and the development of soils, with their accompanying humus, is going on everywhere. COMPARISON OF THE ATLANTIC COAST FORMATIONS WITH THOSE OF THE GULF AND OTHER AREAS The geology of the Gulf region presents many points of difference from that of the Middle Atlantic Coast district, and yet certain comparisons may be insti- tuted on the basis of the faunas and floras by which a correlation of the de- posits in the two areas may be in many instances satisfactorily determined. The similarity of materials is much more marked in the lower portions of the series than in the upper, the Cretaceous and Eocene formations affording many beds of like character and containing similar faunas. The later Tertiary de- posits show marked differences, both in materials and fossils, and little attempt has been made to correlate the strata. Comparisons likewise have not been made in the case of the Quaternary formations. A correlation of the Cretaceous deposits of the Atlantic coast with those of the eastern Gulf cannot be in all instances satisfactorily made, since the Gulf Cretaceous series has never been worked out in detail, and much yet remains to be done in the determination of the range of the species. Strata hitherto called Tuscaloosa are found at the base of the Cretaceous series, in eastern 652 PROCEEDINGS OF THE BALTIMORE MEETING Alabama as well as in Georgia, which must be regarded as identical with the Patuxent-Cape Fear formations of the Atlantic border. There is a marked unconformity at the top of the beds, and deposits supposed to represent the Eutaw, or possibly in part the Tuscaloosa farther west, are found above. Little is known regarding the western extension of these lower beds, although it is possible that they may be found beneath the surface in central Alabama, and perhaps farther westward. These older beds are, so far as known, un- fossiliferous, but are now regarded as belonging unquestionably to the Lower Cretaceous. Reference has already been made to the fact that the Magothy-Matawan- Monmouth formations of the northern part of the Coastal plain are to be corre- lated with the Black Creek-Peedee formations of North Carolina. It seems equally certain that these find their counterpart in the Tuscaloosa-Eutaw- Ripley of the eastern Gulf, with the exception of such portion hitherto referred to the Tuscaloosa as is known to be of Lower Cretaceous age. Very little is known of the fauna of the earliest marine sediments commonly referred to the Eutaw, although the few fossils found come from apparently interstratified marine beds not unlike those in the Black Creek and the Mago- thy. It is also apparent that the fauna of certain strata of the lower portions of what has been regarded as Ripley, on the Chattahoochie river, represents the Black Creek and the Magothy-Matawan, but whether these beds should be con- sidered Ripley or as representing part of an earlier horizon, and thus included in the Eutaw, can only be determined by further investigations. It is largely a question, in any event. as to whether the term Ripley or Rip- leyan shall be used in a broad way to include the beds containing both the lower and upper faunas, in which case even the Eutaw would have to be re- garded as Lower Ripley, or whether two formations are to be recognized to be ealled Ripley and something else, either Eutaw or Tombigbee, as certain stratigraphic and paleontologic facts suggest. Continuous sedimentation, with gradual change in the character of the materials until the beds became wholly or at least largely marine, doubtless continued during the life of these faunas here, as in the other areas, and such facts as are available point to this conclu- sion. Such being the case, the term Ripleyan might perhaps with greater pro- priety be applied, as has been frequently done to the entire fauna, if it seemed inadvisable to restrict it, in which event a new formational name would have to be employed for the upper beds. It is evident that the greater part of the deposits comprising the Tuscaloosa must of necessity be associated with the Upper Cretaceous strata of the Gulf region, and a group term to include this entire series of deposits would not be inappropriate. A final decision on these points, as well as a satisfactory correlation of the Middle Atlantic with the Eastern Gulf deposits must be deferred, however, until more is known of the stratigraphy and paleontology of the latter region. When a comparison of the Atlantic Coast Cretaceous fauna is made with that of the European Cretaceous we find that its general character is that of the Senonian, and the view has been commonly held by invertebrate paleontolo- gists that all of the marine beds of the Atlantic and Eastern Gulf coasts repre- sent that epoch of the Cretaceous, with the possible exception of certain later deposits in New Jersey which have been regarded by the writer and others as of Danian age. Some even include in the Senonian all of the Upper Cretaceous RECENT INVESTIGATION OF COASTAL PLAIN FORMATIONS 653 strata, both marine and non-marine, from New Jersey to the Mississippi basin, since even the lowest known Upper Cretaceous deposits in this area (Raritan formation) contain a few marine invertebrates of possibly identical species with those of higher horizons. Those who hold this view necessarily consider that the earlier Turonian and Cenomanian epochs are unrepresented, since every one now agrees that the unconformably underlying deposits are Lower Cretaceous. It is quite possible, however, that a more exhaustive study of these faunas may show them to be in part of pre-Senonian age. It is essential, however, before passing final judgment on the basis of marine invertebrates to examine the evidence furnished by the fossil plants which occur in great variety in the lowest beds beneath those containing the marine invertebrates, as well as in interbedded strata in the middle of the series. | Berry, who has been engaged in a comparative study of the Cretaceous floras of the Atlantic and Gulf coasts, states that the Magothy-Black Creek flora is iden- tical with that of the Tuscaloosa. Not only do they have the same floral char- acteristics, but the species are in a large number of instances identical. Fur- thermore, the same forms occur in the Woodbine formation in Texas and in the Dakota beds of the West. The flora has been regarded as characteristically Cenomanian, although it may represent the somewhat meager Turonian flora which succeeds it, and therefore belong to that horizon. On the other hand, it is distinctly older than the Montana flora of the West and its Senonian equiva- lent in Europe. The evidence afforded, therefore, by the invertebrates and plants is appar- ently in conflict, since the former present a Senonian facies throughout, accord- ing to many invertebrate paleontologists, while the latter are regarded by paleobotanists to be characteristicaly Cenomanian, or possibly Turonian, in age. In this connection we find in the western Gulf that the Woodbine formation, which is the representative of the Dakota sandstone farther west, and which contains, as already pointed out, a Black Creek-Magothy-Tuscaloosa flora, is succeeded by marine beds known as the Eagle Ford and Austin Chalk forma- tions, which represent the Colorado group farther west,and that these are again succeeded by deposits containing the Ripley fauna, the latter being regarded as the equivalent of the Montana group of the Rocky Mountain district. Since the Dakota has been generally regarded as containing a Cenomanian flora and the Montana a Senonian fauna and flora, the Colorado and its equivalents have been assigned to the Turonian. As the Montana flora is considered by paleo- botanists as quite distinct from and much younger in its facies than the Da- kota, it is difficult to see, if we are not to ignore the evidence of paleobotany, how, as some have supposed, the entire series of Upper Cretaceous sediments on the Atlantic and Eastern Gulf coasts can be assigned to the Senonian. Such a conclusion is still further weakened by the fact that the Woodbine beds may be stratigraphically continuous beneath the Mississippi embayment with the Tuscaloosa deposits farther east in which the same flora occurs. A much more exhaustive study of the stratigraphy of the Cretaceous deposits of the Central and Western Gulf regions is clearly demanded, therefore, before these questions can be finally settled. It is apparent, in any event, that we are still forced to consider the possibil- ity of the Upper Cretaceous sediments of the Atlantic and Eastern Gulf coasts representing horizons earlier than the Senonian. Since the Turonian has not 654 PROCEEDINGS OF THE BALTIMORE MEETING been recognized by either a distinct fauna or flora in the series of conformable strata under consideration, it is quite possible that a Cenomanian flora, once established, continued its existence in America later than the close of the Ceno- manian epoch in Europe. At the same time it is conceivable that the earlier elements of the invertebrate fauna are somewhat older than paleozoologists have recognized, and that a greater or less portion of the series under discus- sion must therefore be regarded as Turonian. The evidence of the plants is certainly favorable to this interpretation, as the European Turonian fiora, although a very sparse one, presents some marked points of agreement with portions of the flora under consideration. f In conclusion, it may be well to direct attention to the fact that the use of the minor European time divisions of the Cretaceous in this connection, as has been often done, may well be questioned in any event, as it is clear from the conflicting evidence presented that it is impossible to assign sharply defined limits to them in the Atlantic and Eastern Gulf regions. The Eocene deposits of the Atlantic Coastal plain show many points of simi- larity with those of the Gulf. The Shark River beds of New Jersey, which apparently overlie the Upper Cretaceous, conformably contain what is probably a Midway fauna, while the Aquia-Nanjemoy formations of Maryland, which are clearly unconformable to the earlier formations, contain a fauna that is distinctly Wilcox, and may be even in part Lower Claiborne. The Trent and Castle Hayne formations of North Carolina are of very late Eocene age, and so far as their molluscan forms are concerned suggest the Jackson, although Bassler has regarded the bryozoan species as Vicksburg, thus making those beds Oligocene in age. No such complete sequence of Eocene strata has been found in the middle and northern Atlantic Coastal plain as in the Gulf, but the faunas found in the beds indicate that they should be correlated with the divisions of the Gulf Eocene above referred to. The insufficient data available from the Miocene and Pliocene formations of the Gulf make it impossible to correlate the deposits of the two areas with any degree of accuracy, although the strata known as Lafayette have been traced along the Piedmont margin to the Gulf district, where the formation was first described. It is impossible to compare the Pleistocene formations of the Atlantic coastal border with those of the Gulf district, as no adequate differentiation of these deposits has been attempted in the latter area. Whether similar terraces occur facing the coast and bordering the estuaries and streams can not be stated as yet. The paper was discussed by Bailey Willis. This paper was followed by the reading of CRETACEOUS FLORAS OF VIRGINIA AND NORTH CAROLINA 655 GHOLOGIC RELATIONS OF THE CRETACHOUS FLORAS OF VIRGINIA AND NORTH CAROLINA BY EDWARD W. BERRY ? [Abstract] ESTTEATeO CUT CLOTS Y ae aries shes a) ot si.ahis “a1 f5) arte eat arene) ees tse) ane (ev silerer eyes. bial vs dvesiclaic'e gree © Ssiele ae, e408 5 8 655 The Lower Cretaceous of Virginia—its correlation and flora....................., 655 hem Upper eCretacCeOUS (Of ViILSiMiaies siaicl cls ales a eloiel snc ss) sie esis) eiieh arse ie sities eheleie ee ee ae 657 The Lower Cretaceous of North Carolina and its correlation....................- 657 The Upper Cretaceous of North Carolina and its correlation.................+..-- 658 INTRODUCTORY The Cretaceous of the Atlantic Coastal plain may be readily divided into two series of deposits—an older estuarine series of clays, lignites, conglomerates, and arkosic cross-bedded sands and a younger marine series of mostly glau- conitic sands. The older attain their best development in Maryland, while the younger are more differentiated in New Jersey, although they attain a greater thickness in the extreme southern Coastal plain. The older deposits abound in fossil plants, while the younger contain an abundant marine, largely inverte- brate, fauna. The transitional beds intercalated between these two series of deposits have consequently a flora more or less closely related to that of the older deposits, while their fauna is more or less closely related to those of suc- ceeding deposits, which facts offer an excellent opportunity for differences of opinion regarding their exact equivalence. These older deposits are found overlapping the eastern border of the Piedmont rocks along the so-called “fall line” from Delaware to Alabama, but are largely covered by the landward transgression of the much later Tertiary deposits, especially in the region from Fredericksburg, Virginia, to Fayetteville, North Carolina, and again in north- eastern Georgia. The Cretaceous deposits of Virginia have been definitely known since the days of Rogers and have been the subject of a voluminous literature. Those of North Carolina have been but recently studied, and are about to be described by Dr L. W. Stephenson, of the United States Geological Survey. The writer collaborated in considerable of the field work, and also had the privilege of studying the fossil plants which were collected. The present brief communi- cation is presented more for the purpose of acquainting geologists with the work in progress than it is to record finished results, in consequence of which a detailed statement is avoided. The three most interesting geologic questions are those of age—that is, correlation, segregation, and paleobotanic features— and in all three categories the present conception differs very materially from those which have gone before. THE LOWER CRETACEOUS OF VIRGINIA—ITS CORRELATION AND F'LORA These deposits coincide with the beds which Professor Marsh insisted were Jurassic in age and which Professor Ward divided into four formations (James River, Rappahannock, Mount Vernon, and Aquia), and from which 1Introduced by W. B. Clark. LXII—BULL. Grou. Soc. AM., Vou. 20, 1908 656 PROCEEDINGS OF THE BALTIMORE MEETING Fontaine and Ward have described or listed about 737 species of fossil plants in 198 genera. Considering for a moment their areal distribution, we find a practically con- tinuous belt from Alexandria to Fredericksburg. Near Fredericksburg the Kocene is.found capping the Cretaceous outcrops, until south of that town the latter are entirely covered as far as the vicinity of Dodson, where a few streams have trenched the Cretaceous beds in a limited area. From Dodson to Richmond they are again buried by both Eocene and Miocene deposits. Be- tween Richmond and Petersburg the James and the Appomattox rivers have cut channels, along which excellent Lower Cretaceous sections are exposed from these towns seaward almost to where the Appomattox enters the James at City Point. Southward from Petersburg to the North Carolina line the Cre- taceous is again buried, only showing itself in the stream bed of the Nottaway river. These deposits are separable into two series, an older and a younger. ‘The older is more or less conglomeritic, with much cross-bedded arkosic sands, con- taining cobbles and clay balls and lenses of green clay, the latter due to the chloritic schists which contributed to the sediments. These clay lenses and balls contain plants. The younger is similar in character, but more uniform, - and was evidently deposited in quieter waters, the sands being often argilla- ceous enough to be ealled clays. The older series is correlated with the Patuxent formation of Maryland because of its similar position with relation to the Piedmont; its practical continuity with that formation in Maryland; its similar lithological character and its identical flora. The European equivalents are, speaking rather broadly, the Wealden or the Neocomian, Urgonien, and perhaps the Aptian. The younger series of deposits is correlated with the Patapsco formation of the Maryland section, of which it is the southern extension, the brownish argilla- ceous sands of Fort Foote, Maryland, carrying an abundant flora, reappearing across the Potomac at Mount Vernon, White House bluff, Aquia creek, etcetera, exactly similar in character and with an equally abundant and identical flora. The Huropean equivalents of the Patapsco formation are the Gault of England and the Albian of continental Europe, the flora of the latter especially, as described from Portugal by Saporta, having not only the same general facies, but containing a large number of similar and several identical types. Speaking broadly, the Patuxent and Patapsco floras are to be correlated with the Glen Rose flora of the Texan region, the Shasta flora of the Pacifie coast, the Kootanie of Montana and Canada, the Lakota of the Black Hills region, and the Kome flora of western Greenland. Exact parallels can not be drawn as yet, although it would seem as if the base of the Kootanie (Morrison) should be placed at a slightly lower level than the base of the Patuxent, and that the Shasta flora should be considered as the flora of the upper unequivocal Cretaceous portion of the Knoxville beds. The floras of the Patuxent and Patapsco are strikingly different in their en- tirety, but contain many similar elements, their distinctions resting largely on the comparatively large number of dicotyledonous plants which for the first time are found fossil in the Patapsco formation. Much has been written, both fanciful and otherwise, of the primitive Angiosperms of the Older Potomac. This was due in part to the inability of previous workers to differentiate these CRETACEOUS FLORAS OF VIRGINIA AND NORTH CAROLINA 657 two formations when present in the same exposure and the consequent mixing of collections. It was also occasioned by undue specific differentiations pro- posed and the diagnostic value assigned to undeterminable fragments. Whereas several hundred species have been described from these beds, there are probably not more than 150 to 250 species capable of recognition. For example, Professor Fontaine describes 10 species of a coniferous genus, Negeiopsis, from these deposits. A most careful revision of all the material discloses but three species, in some specimens at least three of the former specific types being shown on a single branch. The same author describes 42 species of the fern genus Thyrsopteris from this state. I have repeatedly gone over this material, and while I have not decided just where to draw the lines, there are only two distinct types represented in all the material on which these 42 species were based, their seeming diversity being due to individual variations with all terms of the series present, coupled with the differences due to the position on the fronds from which the particular specimens happened to come, the foliage in question being that of a tree fern with large decompound fronds. These are not exceptional cases, but the same is true of genera like Podoza- mites, Cladophiebis, Sequoia, Arthrotaxopsis, Sapindopsis, etcetera. THE UPPER CRETACEOUS OF VIRGINIA No deposits of Upper Cretaceous age have been recognized as outcropping in the Virginia area, although the evidence obtained from deep-well borings in the eastern part of the Coastal plain clearly shows the existence of strata of this age beneath the Eocene. THE LOWER CRETACEOUS OF NORTH CAROLINA AND ITS CORRELATION Entering North Carolina, we find the barnacles of the Lower Miocene sea clothing the decayed granites of the Piedmont near Weldon. Eastward from the fall line at this point the Roanoke river has trenched the Cretaceous sur- face, and characteristic Lower Cretaceous materials are exposed beneath the Miocene in the river bluffs for a score of miles. The next stream which uncovers the Potomac beds is the Tar river, along whose banks low exposures are seen for several miles above and below Tarboro overlain by Later Creta- ceous deposits or Miocene, and the same is true of Contentnea creek. To the southward of the Hatteras axis later conditions seem to have been different from those which existed in northern North Carolina and Virginia, and the Lower Cretaceous is present in force in the Upper Cape Fear basin for about 25 miles above and 14 miles below Fayetteville. The materials are similar to those from Maryland and Virginia. Semi- lithified arkosie coarse cross-bedded sands more or less argillaceous predomi- nate. This formation has been named the Cape Fear formation by L. W. Stephenson. This formation is to be correlated with the Patuxent formation of Maryland and Virginia, since its lithological character is the same, its position on the eastern margin of the Piedmont is the same, and it is overlain unconformably by Upper Cretaceous deposits which correspond roughly to the Magothy and Matawan formations of the Maryland region. The Patapsco formation which is present in the northern Virginia area shows every evidence of pinching out 658 PROCEEDINGS OF THE BALTIMORE MEETING north of the James river. Unfortunately no fossil plants are known from the Cape Fear formation. These are to be expected locally in clay lenses after the manner of their occurrence to the northward, where they are also extremely local. The attitude of the North Carolina Coastal plain, with its almost con- tinuous mantle of Tertiary or surficial deposits, renders exposures compara- tively scarce, and this factor, combined with the more uniformly unfavorable conditions for fossilization, has thus far rendered our search for fossils unsuc- cessful. THE UPPER CRETACEOUS OF NORTH CAROLINA The only Upper Cretaceous formation with which I am concerned is the basal one in this region which marks the transition to the typically marine deposits of the Peedee formation. It has been named the Black Creek forma- tion by Earle Sloan because of the exposures along Black creek in South Carolina. The most northern outcrops of this formation are found in the banks of the Tar river in the vicinity of Tarboro, where they are strikingly unconformable on the Cape Fear formation. Going southward, they are again seen along the Neuse river for a distance of about 20 miles from Blackmans bluff to Golds- boro, and likewise often seen to be unconformably underlain by Cape Fear deposits. Similar exposures are met with in force along the Black river for a distance of about 30 miles. It is along the Cape Tear river, however, that the section is most complete. In this region these beds are found from Rockfish creek near Hope mills, which is a few miles west of Fayetteville to Donohue Creek landing, a distance by the river of something like 65 miles. To the landward they rest with marked unconformity on the Cape Fear formation. Coastward they disappear beneath the typical green sand of the Peedee, which overlies them conformably. The materials are largely laminated sands and lignitie clays. The sands are micaceous and iron stained and of a loose sugary character, often cross-bedded. The usually dark clays are very lignitic and usually thinly laminated. Local lenses of brownish clay carry an abundant flora, which is also present in less abundance in the dark laminated clays. Amber in small globules is uniformly distributed. Toward the top of the formation glauconite makes its appearance in pockets and lenses, accompanied by teredo-bored logs, sharks’ teeth, and marine invertebrates. About 75 species of fossil plants have been collected from this horizon in North Carolina. These are distributed among 24 localities, the bulk, however, coming from a single outcrop, that at Court House bluff on the Cape Fear river, about 39 miles below Fayetteville and 76 miles above Wilmington. The Black Creek formation is tentatively correlated with the Upper Tuscaloosa and Eutaw formations of Alabama, the Middendorf and Black Creek forma- tions of South Carolina, the Magothy and Matawan formations of New Jersey, Delaware, and Maryland, the Woodbine formation of Texas, and the Dakota group of the western interior. It finds its parallel in the Atane and Patoot beds of Greenland. It is difficult to be more exact at the present time, but it seems probable that the Black creek more nearly represents the Magothy- Matawan formations of the more northern Coastal plain rather than the Rari- ———— ee CRETACEOUS FLORAS OF VIRGINIA AND NORTH CAROLINA 659 tan. Judged by European standards, it seems to be late Cenomanian in age. Were the Turonian of Hurope indicated anywhere along our Coastal plain by paleozoological evidence, or were the floras of the European Turonian exten- sive enough for accurate comparisons, I would incline toward correlating the Black Creek formation as well as the Magothy formation with the Turonian. The most abundant plant in the Black Creek formation, a new species of Araucaria, has its nearest relative in a similar species from the Magothy for- mation at Cliffwood, New Jersey, and another from the Turonian of France (near Toulon). Another of the common Black Creek plants, a Pistia, while not found in the Magothy formation, occurs in Greenland (Atane). There is a great resemblance between the flora of the Black Creek formation and those of various European formations which are commonly considered as | Cenomanian in age, such as those of Portugal (Saporta) ; Niederschcena, Saxony (Ettingshausen) ; Moletein, Moravia (Heer) ; Bohemia (Velenovsky). The Society then listened in general session to the reading of the fol- lowing papers : PALEOGEOGRAPHY OF NORTH AMERICA BY CHARLES SCHUCHERT The paper has been published as pages 427-606 of this volume. Then was read REVISION OF THE PALEOZOIC SYSTEMS IN NORTH AMERICA BY E. 0. ULRICH This paper may be published in volume 21 of the Bulletin. Doctor Ulrich’s paper was interrupted by adjournment at 5.45 P. M., and the reading was finished on Thursday. It was discussed by A. W. Grabau. At 7 o’clock Wednesday evening the Fellows and their friends, to the number of 133, gathered at the hotel Rennert for the annual dinner of the Society. President Calvin presided, and, after dinner, remarks were made by him and Messrs Gilbert, Penck, W. B. Clark, G. O. Smith, Brock, Chamberlin, Hovey, Gulliver, Van Hise, Emerson, and Stevenson. The Society convened again at 9.45 o’clock Thursday morning, Presi- dent Calvin being chairman, and, after hearing sundry announcements, listened to the reading by the Secretary of the following REPORT OF THE COMMITTEE ON EARTHQUAKE AND.VOLCANO OBSERVATIONS Acknowledgments have been received from the governors of the Leeward islands, of Hawaii, of Jamaica, and of Saint Thomas, from the chairman of the Isthmian Canal Commission, and from the secretaries of the Smithsonian Insti- tution and of the committee on seismology of the American Association for the Advancement of Science, 660 PROCEEDINGS OF THE BALTIMORE MEETING Hon. W. F. Frear, governor of the Hawaiian islands, writes: “Hawali is an important point for observations of this kind, but how much can be done in this direction is a question. I shall be glad to give what encouragement I can in this matter. The federal government now has a magnetic observatory here, which also contains a seismograph.” William Johnstone, Esq., colonial secretary of Jamaica, writes: “Tn reply I am to state for the information of the Society that the Weather Service of Jamaica has already in use two seismometers in this island, one at Kingston and one at Chapelton, about the center of the island, and that there are now being constructed here about a dozen seismometers on an improved principle.” Colonel George W. Goethals, chairman and chief engineer of the Isthmian Canal Commission, writes: “We have now at Ancon, Canal zone, an observatory equipped with a complete assort- ment of modern, self-recording meteorological instruments, 7. e., barograph, air and water thermograph, hydrograph, barograph 4 poid. triple register (wind direction and velocity, rainfall and sunshine), and the standard instruments necessary properly to correct their records. We expect shortly to erect two horizontal pendulum Bosch-Omori. seismo- graphs—one a hundred-kilogram pendulum instrument (tromometer), which will enable us to obtain registered records on smoked paper of all movements of a telluric nature, either seismic or otherwise, near or distant, and also the variations of the vertical line. The magnification is 100, and the period of oscillation of the tromometer can be extended to forty seconds. Attached to this instrument is an air-damping apparatus, by which the oscillations may be reduced, or even rendered aperiodical. Owing to its sensitiveness, this instrument is well adapted to the registration of earth tremors, pulsatory oscilla- tions, and comparatively quick period earthquake vibrations. “The proposed new equipment, therefore, will be such as to enable us to make obserya- tions in connection with earthquakes, whether of a tectonic nature or produced by vol- eanic action, as well as of other physical phenomena, such as earth tremors and pulsa- tions, which may, as premonitory signs, have a bearing on the prediction of earthquakes. We are also prepared to study the relations that may exist between seismic disturbances, pressure, and temperature. “While we can not make our studies cover the entire field of seismology, we believe our observations will be of considerable utility in the work that the Geclogical Society of America has undertaken.” The chairman of your committee has to report for his own district that, through the efforts of Professor J. B. Woodworth, Harvard University has in- stalled a seismograph which is in active operation, and that money has been given by citizens of Boston whereby another Bosch-Omori instrument has been secured, and plans and drawings are now under consideration with a view to the building of a geophysical observatory near Boston, which will be under the direction of the department of geology of the Massachusetts Institute of Tech- nology. T. A. JAGGAR, JR., Chairman. The Secretary reported from the Council the constitution of W. B. Clark, H. E. Gregory, C. W. Hayes, J. M. Clarke, and E. O. Hovey a committee to confer as to details with a Committee of Organization, which had been chosen by certain paleontologists desiring to form a Paleontological Society as a section of and in close affiliation with the Geological Society of America, the Council heartily commending the project. . USE OF TERM “OPHITIC”’ 661 On motion, the action of the Council was endorsed and the committee given authority to act for the Society. The Society then divided into two sections, and the following papers were presented under the chairmanship of President Calvin: CLASSIFICATION OF CRYSTALS BASED UPON SEVEN FUNDAMENTAL TYPES OF SYMMETRY BY CHARLES K. SWARTZ This paper has been published as pages 369-398 of this volume. The paper was discussed by W. H. Hobbs, EH. H. Kraus, W. N. Rice, andi B. Patton. ‘The following paper was read by title: USE OF “OPHITIC” AND RELATED TERMS IN PETROGRAPHY! BY ALEXANDER N. WINCHELL Contents Page HLaratsTs@) CLULG Us]. Oo TAMMIE P gene oe Notre ois hee aite Ve eu a eve omeuh icuanonete de mclere cunt. ciel iota on src wacais al cushoust canteenela evans 661 JETRERETIUE WISER) is este SGA OPE oO OES ET RES CORE I ERE aCe ITE eee me creer oe 662 Oto dra Elimite OMMMbem csr erek cto ars etre sey crcoeiet cifoma yo alk oh oun otatl aitaTiok ok Siete wr eter aroriohonsto ave sc onens amen a ier 662 WIS PCM fem VNC IONE ViVi as crcl ore lah aiisties oxeu sie: diame MOM nue el ey Selo i Sess bi ala rab ate Sr ue sie.’ aMoPalievreroeane tel alot s 663 LRSI EBC! TOLETDIS Sim to SOR ON ORO EMEC GEES DICL a Peciot cin Cs REI ER Re Tease tu eRe en En Rar gr nie eT 664 SSUMMIVAIRV Ae slerecer ess sake, @ SOL cies wasteeeae Wes eet eeWee RMN ROM eh on cuciot ately aay atone areas o levied oie sieve etaoneaaheets 666 INTRODUCTION For thirty years the term “ophitic’” has been used in petrographic descrip- tions to describe certain textures found in basic igneous rocks, especially dia- bases. It is today used more or less currently wherever such rocks are studied microscopically. And it may be perhaps in some measure due to this wide- spread use of the term by many authors that a difference of usage has devel- oped. This difference of usage is nowhere more clearly expressed than by Lane,? who says: “Tt is to be noted that I use the term ophite, ophitic, as I have heretofore—that is, in accordance with its original definition and in a narrower sense than it sometimes has been used. “Michel Lévy is responsible for the introduction of the term into petrography, and we take the definition from his ‘Structures et Classification des Roches Eruptives,’ page 26: “ ‘When’ the last element consolidated is a bisilicate (generally pyroxenic), its outlines, without their own external contours, are interlarded with other crystals; those of feldspar are notably elongated parallel to the intersection of 001 with 010, or are flattened parallel to 010, and the aggregate assumes a characteristic appearance which 1 described and illustrated as early as 1877 under the name of ophitic structure.’ 1 Manuscript received by the Secretary of the Society December 26, 1908. - 2 Geological Survey of Michigan, vol. vi, part 1, 1898, p. 227. 8 “Quand le dernier élément consolidé est un bisilicate (généralement pyroxénique), ses plages, sans contours extérieurs propres, sont lardées de cristaux plus anciens; ceux de feldspath notamment s’allongent suivant l’aréte pg! (001) (010), ou s’aplatissent suivant gi (010), et l'ensemble prend une apparence caractéristique que j’ai décrite et déssinée dés 1877 sous le nom de structure ophitique.”’ 662 PROCEEDINGS OF THE BALTIMORE MEETING “In this definition there are three points: first, that the pyroxene component is last consolidated; second, that it occurs in areas which are larded, as meat is larded for cooking, with streaks of older crystals; and thirdly, that these crystals are much flat- tened or elongated. Vélain, for example, in his Conférences de Petrographie (page 59), speaks of the ophitic texture as characterized by the elongation of the feldspathic ele- ment, and its distribution through the areas of the ferruginous element (pyroxene). But it has often happened that only the first or third point has been taken to be essential to the definition. Lapparent (Géologie, 1883, page 630) alludes to the tendency of the feldspar to form elongate crystals as characteristic of the ophites, but his figures and descriptions show the areas of pyroxene in which they are embedded. We find that in their experiments on the reproduction of rocks, Fouqué and Lévy apply the term ophite, not to all rocks having elongate feldspar or xenomorphic pyroxene, but to those only that have the structure above described.” PRESENT USAGE Inasmuch as prominent petrographers are therefore not in accord as to the meaning of the word, it is desirable to determine, if possible, what meaning was given to it by its author, and what modifications of that meaning, if any, are justified, either by the usage of the author of the term or by any other means. At the same time its relation to other terms of similar meaning may be advan- tageously brought to light. ; The word has been used in its narrow sense by Lane,* Harker,® Wadsworth,‘ Judd,’ Rutley,* and Teall.® Rosenbusch,” in 1887, made it a synonym of his diabasic (diabasische-kornig) structure in some statements, but in others he uses it in the narrower sense. In 1901 he used ophitic as synonymous with doloritic, diabasic, and divergent- strahlig. If less pyroxene and some residual glass were present he called the structure intersertal. Kemp used ophitic in the wider sense in the first edi- tion of his well known ‘‘Handbook of Rocks,” but in later editions he changed to the narrower meaning. Lacroix” defined the term in the narrow sense in 1896, but in 1899 he used it in the wider sense. Among others who have used the word in the broader sense are Zirkel,” Williams,“ Loewinson-Lessing,” Rinne,** Lawson,” Clements.® ORIGINAL DEFINITION As mentioned by Michel Lévy in the definition quoted by Lane, the former 4Loc. cit. See also Bulletin of the Geological Society of America, vol. 18, 1906, p. 648. 5 Petrology for students, 1897, p. 126. 6 Geological and Natural History Survey of Minnesota, Bulletin 2, 1887, p. 107. 7 Quarterly Journal of the Geological Society, 1885, p. 360; 1886, p. 68. 8 Granites and Greenstones, 1894, p. 14. 9 British Petrography, 1888, p. 135. 10 Mikr. Phys., 2 auflage, 1887, II, pp. 190, 191. Elem. Gest., 2 auflage, 1901, p. 326. 11 Handbook of rocks, 2d ed., 1900, pp. 44, 158; 38d ed., 1906; pp. 71, 210. 12 Minér. France, II, 1896, p. 34. Le Gabbro du Pallet, 1899, p. 28. 18 Lehrb. Petr., 1893, I, p. 689. 1440. S. Geological Survey, Bulletin 62, 1890, p. 196. American Journal of Science, vol. xliv, 1892, pp. 482, 492. if 15 Geological Survey of Michigan, vol. vi, part 1, p. 227, footnote. 16 Gesteinskunde, 1901, p. 87. 17 Geological Survey of Canada, Annual Report, vol. lil, 1887, p. 58F, 18 TJ, S, Geological Survey, Monograph xxxvi, 1899, p. 200, USE OF TERM “OPHITIC”’ 663 defined the structure characteristic of ophites as early as 1877,.in terms not identical with those quoted by Lane; the original definition is as follows :” “The ophites are characterized by the constant presence of diallage or of augite alter- ing to diallage; this bisilicate molds the elongated crystals of triclinic feldspar, gener- ally clustered in groups, which do not deserve the name of microlites in spite of their elongation and rather small dimensions; this aggregate habitually encloses old crystals of titanic iron. It is to this characteristic grouping of feldspar of recent consolidation and of diallage still more recent that the ophites owe their structure intermediate be- tween the granulitic and the microlitic structure, but actually more closely related to the former.”’ There is in this original definition no statement that a single pyroxene must inclose several feldspar crystals; there is, on the contrary, the simple statement that “it is to this characteristic grouping of feldspar of recent consolidation and of diallage still more recent that the ophites owe their structure.” The essential thing is simply that the feldspars formed before the pyroxene. Ac- cording to the original definition, therefore, the word ophitic has a broad meaning, applying to all cases where the plagioclase crystals formed before the pyroxene, and is not to be confined to those instances where the pyroxene occurs in large anhedra inclosing the feldspar in poikilitic fashion. USAGE OF MICHEL Livy Proceeding now to the usage of the author of the term, we find that in the great Minéralogie Micrographique of Fouqué and Michel Lévy, published in 1879, the term is defined (page 153) as follows :” “The ophitic texture in which the crystals of feldspar are elongated parallel to one of the sides of the face 010, forming thus a type grading toward the microlitiec rocks.” It would be difficult to state more clearly a definition depending not upon two or three con- ditions, but upon one alone, and that one is here stated to be the elongation of the feldspar. Such elongation necessarily involves the crystallization of the feldspar before the final solidification of the rock. In the same work the struc- ture is illustrated by several photomicrographs, which show that the term is applied to rocks in which pyroxene (or a related mineral) crystallized after feldspar; they also show (plate xxxvi, figure 2) that the pyroxene is not neces- sarily in large areas, but may be in small grains (“augite en microlithes globu- leux’”’), no one of them large enough to inclose the long lath-shaped crystals of plagioclase. When Michel Lévy wrote his ‘Structure et Classification des Roches Eruptives,” in 1889, he referred directly to the original definition quoted 1 Bull. Société Géologique de France, vol. vi, 1878, p. 158. Read December, 1877. “Les ophites sont caractérisées par la présence constante du diallage ou d’un augite passant au diallage; ce bisilicate moule des cristaux allongés de feldspath triclinique, généralement groupés entre eux, et qui ne meritent pas le nom de microlithes malgré leur allongement et leur dimensions assez exigués; le tout englobe habituellement des cristaux anciens de fer titané. C’est a ce groupement caractéristique de feldspath de consolidation récente et de diallage plus récente encore que les ophites doivent leur struc- ture intermédiaire entre la structure granulitique et la structure microlitique, mais se rattachant en réalité plus intimement & la premiére.”’ 20 “Ta structure ophitique, dans laquelle les cristaux de feldspath s’allongent suivant lun dés cétés de la face gi (010), formant ainsi un type de passage vers les roches microlitiques.”’ 664 PROCEEDINGS OF THE BALTIMORE MEETING above. It is therefore clear that the statement that the pyroxene masses are interlarded with older crystals, especially elongated feldspar (“ses plages, sans contours extérieurs propres, sont lardés de cristaux plus anciens; ceux de feldspaths notamment s’allongent’’), must be taken to include not only the tex- ture, which is poikilitic, but also the structure, in which the fine granular pyroxene masses are penetrated by lath-shaped plagioclase erystals of indefi- nite orientation. In other words, it includes all cases in which the elongated plagioclase crystallized before the pyroxene (or other ferromagnesian) constit- uent of the rock. At the time that Fouqué and Michel Lévy™ attempted to reproduce the ophitic texture artificially in 1881 they defined it as follows :* “As is well known, these rocks are characterized by the development of microlites of triclinic feldspar, molded and often inclosed by extensive areas of pyroxene.” Here the large areas of pyroxene are included in the definition, perhaps because this type of the ophitic texture was the one actually obtained experimentally. But the definition can not refer to a variety of the poikilitic texture alone, since these areas either inclose ov mold themselves about the earlier feldspar crystals. Furthermore, the text states that the “large” areas of pyroxene had an average diameter less than twice the length of the feldspar crystals. When Fougué and Michel Lévy reported the discovery of a mineral erro- neously called diamond in South African rocks, they described the inclosing rocks*® as follows: “Their type of texture, very uniform, is ophitic; they are rocks entirely crystalline, in which the feldspathic element is elongated parallel to the axis a, while all the other minerals of later consolidation are granu- litic.” Here the important characteristic of the texture is clearly stated to be the early crystallization of the feldspar with resultant automorphic elongation. RELATED TERMS So far as the writer is aware, of all the terms that have been used as more or less exactly synonymous with ophitic, Zirkel’s intersertal* is the only one that has the right of priority as compared with Michel Lévy’s term. Zirkel defined the intersertal structure as present in “Feldspar basalts consisting of larger erystals and an apparently amorphous and not individualized matrix, pressed and squeezed into the spaces between the divergent sections of the phenocrysts, and so reduced in amount that it does not at all play the part of a true ground- mass.” Of this structure he names three varieties: First, that in which the groundmass (zwischengeklemmte Masse) is wholly of glass; second, with the groundmass “half glassy” by the appearance of granules in it; third, with the groundmass so abundantly supplied with needles and granules that only a little 2 Bull. Soe. Min. Fr., vol. iv, 1881, p. 277. 22“On sait que ces roches sont caractérisées par le developpement de microlithes de feldspath tricliniques, moulés et souvent englobés par des plages étendues de pyroxéne.” 22C. R., LXXXIX, 1879, p. 1125: “‘Leur type de structure trés uniforme, est ophitique ; ce sont des roches entiérement cristallisées, dans lesquelles l’élément feldspathique est allongé suivant l’aréte pg}, tandis que les autres minéraux de seconde consolidation sont granulitiques.”’ 2% Basaltgesteine, 1870, p. 111: “Feldspathbasalte, bestehend aus gréssern Krystallen und einer zwischen die divergirenden Durchschnitte derselben gedringten und geklemm- ten, als solche amorphen und-nicht individualisirten Masse, welche an Quantitit zuriick- tretend, keineswegs die Rolle einer eigenlichen Grundmasse spielt.”’ USE OF TERM “‘OPHITIC”’ 665 glass remains. According to its original definition, therefore, the intersertal structure requires large euhedral crystals in divergent groups in a groundmass which contains more or less glass. In this form it would seem to apply very well to certain coarsely spherulitic textures rather than to the ophitic texture. It may be said that the later usage of various writers, notably Rosenbusch and Zirkel, gives the word a somewhat different meaning, making it apply to a tex- ture in which rudely divergent feldspar crystals occur in a base containing more or less glass. In this sense the word is later than ophitic, and therefore can be regarded as nothing more than a variety of the latter, in which glass is present in the groundmass (‘“mesostasis’’ ). Other terms, which are somewhat related to ophitic in their meaning, include luster-mottled, “divergent-strahlig-kornig,” diabasic, doleritic, radiolitic, and poikilitic. These terms are all of later origin than ophitic. Their history may be summarized as follows Pumpelly*® proposed the term luster-mottlings (whence, of course, luster- mottied) only a month later than the date of Michel Lévy’s article on ophites and their structure. The term was quite fully described and applied to those ophitie textures which are also poikilitic. It would probably be more com- monly used if it were less cumbrous. It is an exact synonym of ophitic in the narrow sense advocated by Lane. Lossen* is the author of the awkwardly long expression “divergent-strahlig- kornig.” He defined it in 1880 thus: “Especially the diabases of the horizon under discussion are accustomed to possess dominantly a more or less distinct divergent radial-granular, not pure-granular, struc- ture, in which the lath-shaped development of the plagioclase individuals dominates the fabric, so much, indeed, that the rest of the mineral particles are arranged between the meshes of the feldspar laths.”’ The essential thing in this definition is the dominance of lath-shaped plagio- clase erystals in the texture. The term is therefore a synonym of ophitic. Loewinson-Lessing,” in 1887, suggested the shorter term radiolitic (radio- litische) as a substitute for Lossen’s term. In the same year Rosenbusch* proposed the form diabasic (diabasisch-k6r- nig) for the ophitic texture. His description of this texture was as follows 2 Proceedings of the American Academy, vol. xlii, 1878, p. 260. 26 Jahrbuch k. pr. geologische Landesanst, 1880, p. 8: ‘“‘Speciell die Diabase des im Rede stehenden Horizontes pflegen vorwiegend eine mehr minder deutlich divergent- strahlige-kérnige, nicht rein kérnige Structur zu besitzen, wobei die leistenformige Aus- bildung der Plagioklas-Individuen das Geftige beherrscht, so zwar, dass die tibrigen Min- eralgemengtheile zwischen das Maschenwerk dieser Feldspathleisten eingeordnet sind.”’ ZaMe Pa M.. Vol. ix, L88ii, ip: 70: 28 Mikroskopische Physiographie, 2 auflage, II, 1887, p. 190: “‘Die Structurformen der Diabasgesteine zeigen trotz manchen, meist localen und wenig verbreiten EHigenthiimlich- keiten eine gewisse Monotonie. Betrachtet man zunichst die Structur der Diabase nach ihren Hauptcharakter, so gehodrt dieselbe mit Entschiedenheit zu den hypidiomorph k6rnigen; im Vergleich mit den typischen stockfOrmigen Tiefengesteinen stellen sich jedoch eine Anzahl abweichender Verhidltnisse hereaus, denen zufolge fast alle Forscher der Diabasstructur eine Sonderstellung einriumen und sie als ‘ophitisch’ (Fouqué und Michel-Lévy), ‘divergent-strahlig-k6rnig’ (Lossen), oder diabasisch-ké6rnig bezeichnen. Diese Higenthiimlichkeiten lassen sich auf zwei Ursachen zuritickfitihren; die meistens sehr ausgesprochene Leistform der Plagioklase und die friihere oder doch nicht ausges- prochenen spitere Krystallisation derselben aus dem Magma im Vergleich zu den pyroxe- nischen Gemengtheilen.”’ 666 PROCEEDINGS OF THE BALTIMORE MEETING “The structures of diabase rocks, in spite of many chiefly local and not widespread peculiarities, show a certain monotony. If one considers first the structure of the dia- bases according to its chief characteristic it belongs with certainty to the hypidiomor- phic granular type: in comparison with typical [bathylith- or] stock-shaped abyssal rocks they present, however, a number of differing relationships to which consequently nearly all students of the diabase structure have granted a separate designation, and have named ‘ophitic’ (Fouqué and Michel Lévy), ‘divergent-strahlig-kérnig’ (Lossen), or diabasic-granular. These peculiarities may be traced back to two causes; the usually very distinctly lath-like shape of the plagioclases, and the earlier, or at least not dis- tinctly later, crystallization of the same from the magma in comparison with the pyrox- enic constituent.” In 1901 Rosenbusch” used ophitic chiefly in the narrow sense, and added an- other synonym (doleritic) to the word in this sense. He also used intersertal as descriptive of the texture of a rock containing little pyroxene and some glass. In 1886 Williams® proposed the term poikilitic (first spelled poicilitic, then peecilitic, and finally, in 1893, poikilitic) to designate a rock structure in which one mineral in large individuals envelopes smaller individuals of other minerals which are not regularly arranged. It differs from ophitiec in the narrow sense above defined in being applicable irrespective of the nature of the inclosed ‘or of the inclosing mineral, and also in being applicable whether the inclosed mineral have definite form or not. But as applied to one mineral inclosing rounded individuals of other minerals, it should not be used, since other terms have priority, notably “globulaire’ of Michel Lévy,* for the English equivalent of which the writer would suggest that globulitic is to be preferred to globular. The term was first applied to rounded quartz grains in a glassy base; later its meaning was extended to apply to rounded grains inclosed by other minerals. For this latter sense Salomon’s contact® structure and Bayley’s granulitic® structure are synonyms, although they are also applicable to a finely granular structure made up almost entirely of small rounded grains, a grain of one min- eral sometimes inclosing one or more of another mineral. SUMMARY To summarize: a texture exists quite commonly in rather basic igneous rocks which has received many names. It is a texture characterized by the fact that the plagioclase feldspar, contrary to the usual order of crystallization, consoli- dated in lath-shaped forms before the ferro-magnesian constituents. This tex- ture was defined and illustrated by Michel Lévy in 1877, when he declared it was characteristic of the group of rocks he called ophites. Since then the term 22 Blem. Gest., 2 auflage, 1901, p. 326. 80 American Journal of Science, vol. xxxi, 1886, p. 30; xxxiii, 1887, p. 139. The term Poikilitic was proposed by Conybeare to designate the ‘‘New Red Sandstone,” or Permian and Triassic (together) of England. It was used also by De La Beche, John Phillips, and H. B. Woodward in the same sense. T. H. Huxley (Geological Magazine, vol. vi, 1869, p. 89) suggested that it be used to refer to terrestrial deposits of Permian and Triassic age, and he thought such deposits in some cases indicated continuous fauna rather than changing fauna. But the use of the term in this sense is now wholly obso- lete, and, even if it should be revived, it could cause no confusion with the use proposed by Williams. See also: Journal of Geology, vol. i, 1893. p. 176. 31 Bull. Soc. Geol. Fr., vol. ili, 1875, p. 199. 32 Z. d. d. geol. Gesell., vol. xlii, 1890, pp. 487, 511. 33 Journal of Geology, vol. ili, 1895, p. 1. USE OF TERM “OPHITIC” 667 ophitic has come into wide usage, but it is now used with either one of two different meanings. Some writers follow the original definition and the prac- tice of its author in applying the term to all rocks having plagioclase in lath- shaped erystals of early formation. Others, apparently misunderstanding a much later description of the texture,* confine the term to those rocks whose Jath-shaped feldspars are poikilitically inclosed by large anhedra of pyroxene. It seems evident from both the original definition and from the usage of the author that, while such a poikilitic arrangement is included, it is not essential to the texture; and it appears that pyroxene itself is equally non-essential ac- cording to the usage of the author, since he says the last mineral to erystallize is generally pyroxene, and, moreover, applies the term ophitic to a rock from Greenland® in which the pyroxene is replaced by native iron. It appears, therefore, that the term ophitic should be used in the broad sense already defined, for which usage it has clear priority over all other terms. Furthermore, if a rock with ophitic texture has glass in the ground- mass the texture may properly be called intersertal, which thus designates a variety of the ophitic texture. It appears also that the terms divergent-strah- lig-kornig of Lossen, radiolitic of Loewinson-Lessing, and diabasic and doleritic of Rosenbusch are needless synonyms of ophitic. Finally, it may be suggested that if luster-mottled be considered too cumbrous a term to describe a texture which is at once ophitie and poikilitic, it might well be called poikilophitic. Then was read CHEMICAL COMPOSITION AS A CRITERION IN IDENTIFYING METAMORPHOSED SHDIMENTS BY EDSON S. BASTIN 1? [ Abstract. | This paper called attention to the small number of definite statements, even of a qualitative character, in geological literature, as to the nature and value of chemical criteria in distinguishing schists of sedimentary from those of igneous origin. Quantitative statements are wholly wanting. By compiling a large number of analyses of pelitic sediments the writer showed the nature of the chemical changes involved in their metamorphism. He then proceeded to contrast the composition of the pelitic schists and gneisses with that of their allies among igneous rocks. The calculation of the “norm” of a schist and its classification, according to the quantitative system of Cross, Iddings, Pirsson, and Washington, was pointed out as a convenient method for making such comparisons. . These statistical studies brought out not only the character of the chemical criteria which may be used, but gave a quantitative measure of their value. The paper concluded with the application of these criteria to certain selected schist and gneiss analyses. 84 A. Michel Lévy : Structures et Classification des Roches £ruptives, Paris, 1889, p. 26. 3 C. R., vol. xcii, 1881, p. 891, and Ann. Ch. Phys., vol. xvi, 1879, p. 505. ‘Introduced by G. O. Smith. 668 PROCEEDINGS OF THE BALTIMORE MEETING The discussion on this paper was participated in by B. K. Emerson, W. 8. Bayley, F. D. Adams, and E. S. Bastin. After this the following paper was read by title: PETROLOGY OF THE SOUTH CAROLINA GRANITES (QUARTZ MONZONITES) BY THOMAS LEONARD WATSON The next two papers, being on related topics, were presented orally in succession : TERTIARY DRAINAGE PROBLEMS OF EASTERN NORTH AMERICA *BY AMADEUS W. GRABAU [Abstract] The Laurentian river of Spencer carried the collected drainage of the Great lakes through Ontario valley and out by the way of the present Saint Law- rence. The Finger Lake valleys and the Genesee are regarded as made by tributary northward flowing streams. Fairchild regards these as northward flowing tributaries of a (possibly) westward flowing river in the Ontario valley. The author has in the past shown that a normal sequential drainage system, the general direction of which was northward, and in which the minor streams were beheaded by the master, accounted for all the topographic fea- tures of the region in question. Subsequent blocking of some of the channels by drift and deepening of others by ice, and a general depression of the country to the northeast, has produced the present drainage system. The problems were discussed in the light of accumulated facts. DRAINAGE EVOLUTION IN CENTRAL NEW YORK BY H. L. FAIRCHILD [Abstract] The paper aims to assist in the elucidation of the complex physiography of the western helf of New York state. Three maps represent graphically the general evolution of the drainage and the interference by glacier invasion of the normal stream development. The first map shows the existing valleys which are, apparently, an inher- itance from the ancient drainage, southwestward, across the uplifted pene- plain. These inherited valleys fall into three classes: (@) those in which the present flow is the same as the primitive, (0) those which are abandoned or left as “hanging” valleys, and (c) those in which the stream flow has been reversed. A remarkable parallelism is exhibited by these valleys, which, except in the district of the Delaware and upper Susquehanna, are transverse to the present master streams. At Lanesboro the primitive Susquehanna con- tinued directly south, instead of bending northwest as now, and then occupied in Pennsylvania the Tunkhannock valley. Other valleys in northern Pennsyl- vania represent the continuation of the southwestward fiow in central New York. DRAINAGE EVOLUTION IN CENTRAL NEW YORK 669 The second map exhibits the hypothetical Tertiary drainage. During later Tertiary time all the drainage of the west half of the state was diverted west- ward (subsequent) and northward (obsequent) into a great trunk stream that occupied the Ontario and Hrie valleys and probably drained westward into the Mississippi basin. The cause of this radical reversion of flow was the great thickness of non-resistant rocks in the Ontario district. In the vertical series of strata between the Trenton and the Portage, on the Cayuga meridian, are 5,150 feet of rock, of which 4,500 feet are weak shales, 350 feet limestone, and 250 feet sandstone. The pre-Glacial divide was far south in Pennsylvania. The Allegheny sys- tem poured north through the lower Cattaraugus valley. The upper Genesee was tributary to the broad Dansville-Avon river, which almost certainly had its northward course through the Irondequoit valley. The Susquehanna turned west from the site of Lanesboro and Susquehanna villages along the strike of the Chemung strata (which were less resistant than the overlying Catskill), past the sites of Binghamton, Owego, and Waverly, and then curved north through the sites of Elmira and Horseheads and occupied the Seneca valley. The Che- mung was the principal tributary from the west, as today, but it passed north of Elmira instead of south, where it now lies in a post-Glacial cut. The Delaware and the upper tributaries of the Susquehanna were not di- verted from their southwest courses. Along the Ontario lowland the Tertiary channels are almost entirely de- stroyed or obscured by drift, but the valleys of Irondequoit, Sodus, Little Sodus, and Fairhaven are trenches across the Niagara-Medina scarp, which probably represent the northward pre-Glacial fiow. Today only two large streams pass across this rock ridge, the Genesee and Oswego, both in new channels. It seems probable that along the belt of Salina outcrop the pre- Glacial tributary streams flowed east or west as they do today. It is suggested that the “oversteepened” walls of the bottom sections of the Finger Lakes valleys were produced by the rapid down-cutting of the streams during the Tertiary uplift. The third map shows the principal stream flow as compelled by the ice- sheets. A few strong south-leading valleys were enlarged or newly cut by the concentrated glacial waters, and the Allegheny and Susquehanna systems were turned to the south. In order from west to east the glacially developed valleys are Cassedaga, Conewango, Ischua, Canisteo, Cohocton, Cayuta, Cattatonk, Tioughnioga. These southeastward drainage lines, transverse to the primitive flow, were carved from numerous, short, subsequent valleys by the stream flow forced to the southward by the ice-damming. Such flow was effective during the advance of the ice-sheet, but stronger during the waning of the ice, and probably more than one ice invasion has been concerned. On the Ontario lowland the forced drainage was west or east, alongside the ice margin. In the Erie basin the later flow was all westward past the ice front. In the Mohawk valley the drainage between Little falls and Rome was turned from west to east. The water-parting which in pre-Glacial time lay in Pennsylvania has been so changed by glacial flow that it now lies close to the Finger lakes. Between the two or more ice invasions lang epochs of warm climate prob- ably permitted some development of valleys, which would be more or less 670 PROCEEDINGS OF THE BALTIMORE MEETING buried by subsequent glaciation. This interglacial work is the most elusive or indeterminate element in the large problem. The last map shows only the final drainage as it has been left by the later Wisconsin ice sheet. In detailed or local study the buried and discordant valleys must be considered. Nearly all the valleys of central and western New York may be grouped into three classes according to their direction: (1) Those with southwestward direction, which seem to be mainly inherited from the ancient drainage across the uplifting plain. (2) Those leading northward (northeastward in the Erie basin), developed by subsequent flow toward the great master stream in the axis of the Ontario-Erie valley. (38) Those leading southeastward, produced by glacial waters forced toward southern escape. These papers were discussed together by A. W. Grabau, J. W. Spencer, F. Carney, A. P. Brigham, G. F. Wright, F. B. Taylor, A. P. Coleman, and H. L. Fairchild. At 12.40 o’clock the Society adjourned for luncheon, meeting again at 2.05 o’clock to continue the reading of papers. President Calvin occu- pied the chair. The first two papers were read by title. They were SOME PHYSIOGRAPHIC FEATURES OF THE SHAWANGUNK MOUNTAINS BY GEORGE BURBANK SHATTUCK NANTUCKET SHORELINES, II BY F. P. GULLIVER Then was presented orally NANTUCKET SHORELINES, IV BY F. P. GULLIVER [Abstract] The strong north and northeast storms of the past fall have closed the Haul- over, and the tombolo from Wauwinet to Coskata was completed on November 12, 1908. Some old maps have been studied with reference to the former east- ward extension of the oldland at Wauwinet, Coskata, and Folger islands. The changes on Great point since 1896 were compared with previous conditions and with what may be expected in the future. The shoals between Nantucket and Cape Cod and. between Nantucket and Marthas Vineyard and the Hyannis shore are considered as attempts of the sea to build tombolos. After this was presented orally NOTE ON STRIATIONS, U-SHAPED VALLEYS, AND HANGING VALLEYS PRO- DUCED BY OTHER THAN GLACIAL ACTION BY EDMUND OTIS HOVEY This paper has been published as pages 409-416 of this volume. The paper was discussed by A. Penck. TITLES OF PAPERS 671 Then was read by title HISTORICAL NOTES ON HARLY STATE SURVEYS BY GEORGE P. MERRILL The next paper read was IRON ORES OF MARYLAND BY JOSEPH T. SINGEWALD, JR* [Abstract] This paper presents a brief summary of the results of an investigation car- ried on during the past season on the iron ores of Maryland under the auspices of the Maryland Geological Survey. Four classes of ore were recognized— limonite, hematite, magnetite, and siderite. ‘The paper presented embraced a discussion of the character and chemical composition of each of these ores, the localities in which the deposits occur, and also their geologie and stratigraphic relations. After this was presented orally SHORTAGE OF COAL IN THE NORTHERN APPALACHIAN OOAL FIELD BY I. C. WHITE This paper has been published as pages 333-340 of this volume. The next paper was read by title. GLACIAL CHARACTER OF THE YOSEMITE VALLEY BY FRANQOIS MATTHES* Then was presented orally THE MILLS MORAINE WITH SOME DISCUSSION OF THE GLACIAL DRAINAGE OF THE LONGS PEAK (COLORADO) DISTRICT BY EDWARD ORTON, JR? This paper was discussed by W. T. Lee. The next paper read was QUARTZ AS A GHOLOGIC THERMOMETER BY FRED E. WRIGHT AND E. S. LARSEN [Abstract] Observations by Le Chatelier and Mallard in 1889-1890 proved that at about 570 degrees quartz crystals undergo a reversible change, the expansion-coeffi- 1 Introduced by Wm. Bullock Clark. 2Introduced by F. P. Gulliver. LXIII—BULL. GrOoL. Soc. AM., VoL. 20, 1908 672 PROCEEDINGS OF THE BALTIMORE MEETING cient, birefringence, and circular polarization all changing abruptly. O. Miigge (Neues Jahrbuch, Festband, 1907, 181-196) has recently considered the problem again in detail, and by means of etch figures combined with crystallographic behavior on heating found that below the inversion point quartz crystallizes in the trapezohedral-tetartohedral division of the hexagonal system, while above 570 degrees it is trapezohedral-hemihedral. The high form is very similar to the low form, and differs chiefly in the fact of its common planes of symmetry. A plate formed above 570 degrees is trapezohedral-hemihedral, but on cooling it changes to the trapezohedral-tetartohedral division, thereby losing its com- mon planes of symmetry, which may then become twinning planes. It is to be expected, therefore, that quartz crystals thus cooled will be irregularly and intricately twinned after (1010.), while low temperature quartzes are simple or regularly twinned. It is furthermore evident, on considering the genesis of quartz at different temperatures, that intergrowths of right and left handed quartz are limited chiefly to quartz crystals formed below 570 degrees. These two criteria can be used to distinguish quartz which has been formed or heated above 570 degrees from quartz which has never reached that temperature. The object of the present investigation has been to test the general validity of the theoretical conclusions on a number of quartzes from different kinds of rocks and veins, as well as to determine more accurately the inversion tempera- ture. SESSION OF THURSDAY, DECEMBER 31 The sectional meetings for papers on stratigraphic, areal, and paleon- tologic geology was called to order at 10 o’clock Thursday morning by W. B. Clark, who was then elected presiding officer. E. R. Cumings acted throughout as secretary by request of the Secretary of the Society. The first paper read was OCCURRENCE OF THE MAGOTHY FORMATION ON THE ATLANTIC ISLANDS BY ARTHUR BARNEVELD BIBBINS [Abstract] The Magothy formation (of mid-Cretaceous age), as originally defined by Darton, was supposed by that author to be limited to the state of Maryland, although its partial equivalent, the “alternate clay-sands,”’ was earlier men- tioned by Uhler as occurring much farther northward. Recent investigations, paleobotanical and stratigraphic, by Hollick, Berry, and the writer, have ex- tended the lines of the formation far southward, and northward across New Jersey and along the Atlantic islands as far as Marthas Vineyard. The occur- rence on these islands was shown by local sections and photographs. The deposits are richly plant bearing, with grains of amber associated, as on the Magothy river. The formation suffered considerable corrugation by the great ice-sheet. The paper was discussed by David White and A. B. Bibbins. TERTIARY EROSION INTERVALS—NORTH CAROLINA AND VIRGINIA 673 The next paper read was EROSION INTERVALS IN THE TERTIARY OF NORTH OAROLINA AND VIRGINIA? BY BENJAMIN L. MILLER Contents Page introduction 4:...... - ppnea lt bean ear aa 5 HAS 6 OG TE 6B BRE RUT ECC ne ae 673 DIDEDED. TOI BOINE, Ba io. G8 alos ely Ca0U BO 00.0. CHO.O 6 O.0.G 0.8/6 O1UIO cyUrG On0 OsO CCAD ICRON OI RCEEC ECR NaC 674 OStOCCHEMELOSTOM = iltelivialllere ch cecieta of tet ovcren er sue tstel cae? oh cere ovclcrievicilc ee cilere) he's aisis. oe sie esis 675 VG COMO ONIN AELOIN Site creer siete orc co enai elon) ohiastel seinvte) suis ieee (aivelielamarlay a: averiala leteviele of SS eieiai oe \e eee es 676 EN FOCEM CRE LOGIN A TIO Mier coyepanate ala cron stata oe ck aneis! =) ores ial reel sisi chehe: oevieusbsiterels s/fels g's e Jase leleve ie #6 677 Relations of the North Carolina Tertiary formations...............-...2-22020- 677 ease MEET SPANOS et ue tere say cist oie 6a) ite n) a oits'c Gb cuss © aisle eioua'o aaa sb ee ela als sebiele Oe Edie ee 678 INTRODUCTION In the Atlantic Coastal plain the recognition of unconformities is not an easy matter. This is due to several causes. In the first place, the formations in general represent littoral deposition, and the character of the materials changes very rapidly, both horizontally and vertically. For this reason it is difficult to definitely recognize the same formation by its lithologie character- istics over wide areas except where we have continuous exposures. Second, the covering of Pleistocene sands, gravels, and loams has concealed the under- lying deposits over the stream divides to such an extent that outcrops can only be found at occasional intervals in the stream valleys. With practically all of the streams that are of sufficient size to have cut through this surface covering, flowing in the same general direction—to the southeast—there are few con- tinuous exposures from one major drainage basin to the other, and since the lithologic characteristics may be dissimilar in two adjacent valleys, it becomes impossible to determine definitely whether the strata in the two places repre- sent the same beds or not. Further, the fossiliferous strata occur in the form of lenses of variable extent separated by non-fossiliferous strata. Thus the absence of a fossil layer in one valley and its presence in an adjacent one does not necessarily mean that erosion has removed it from the former place. Again, the dip of the strata composing the Coastal plain is slight, especially in the case of the Tertiary strata, seldom exceeding 15 to 20 feet per mile. This varies somewhat in the different formations, though it is very unusual to have two formations in contact that exhibit different inclinations of sufficient mag- nitude to prove the presence of an erosional unconformity between them. During the Tertiary period there is evidence to prove the submergence and elevation of the Coastal plain as a whole a number of different times, although seldom was the region elevated sufficiently to permit streams to carve valleys of any considerable depth before a succeeding depression took place. For the reasons given above, throughout the Coastal plain generally the various forma- tions recognized are apparently conformable in that few irregular lines of con- tact can be discovered between them. The unconformities determined are mainly those of overlap. These overlap unconformities are exhibited in the northern part of the Atlantic Coastal plain in New Jersey, Delaware, and Maryland particularly, and have been described in the published literature. Similar unconformities are recognized in Virginia, and no doubt they have 1 Manuscript received by the Secretary October 15, 1909. 674 PROCEEDINGS OF THE BALTIMORE MEETING been equally prominent in North Carolina, though there we have less evidence for determining their presence, while there is much more evidence of the deposition of each formation upon an irregular erosion surface of earlier formations. In the Coastal plain of Virginia and North Carolina the Tertiary strata have been studied in detail only within the last few years, and as yet the divisions recognized have not appeared in print. For this reason it is well to speak briefly of the formations. Ko0cENE FORMATION In Maryland the Eocene consists of two formations, the Aquia and the Nanjemoy, which are, so far as determinations can be made, perfectly con- formable, though resting upon the underlying marine Cretaceous which they gradually overlap, and in southern Maryland and Virginia they extend over the edges of the marine Cretaceous and come to rest upon the underlying deposits of the Potomac group. The marine Cretaceous does not appear in Virginia because of this overlapping cover of Eocene strata, though it makes its reappearance in North Carolina, where the Hocene deposits have suffered much erosion. The Hocene formations of Maryland extend across the Potomac river, and reappear with the same lithologie and paleontologie characteristics in Virginia, extending a number of miles to the eastward of the “fall line,” and extending southward as far as the James River drainage basin. From that point southward the Eocene is covered up by later deposits of Miocene — and Pleistocene materials, and when the Roanoke and Tar River drainage basins in North Carolina are reached we find that the Hocene is entirely absent. In the valleys of those streams the Miocene is found everywhere rest- ing directly on the underlying Cretaceous. In the southern part of North Carolina the Hocene reappears, and there we find it again represented by two formations, though these are distinctly different from the Eocene strata of Virginia and Maryland. Lithologically the difference is very striking, in that the glauconitic phase of the northern Coastal Plain Eocene is lacking, and in its stead we have deposits of fine-grained calcareous marls or limestones. Lithologically the North Carolina deposits belong to the Gulf phase rather than the North Atlantic Coastal Plain type. AIso in the fossil content there is a marked difference between the North Carolina and the Virginia Eocene formations, though as yet the paleontologic work has not progressed far enough to definitely determine just how great a faunal gap exists between the two series. The more recent age of the North Carolina Hocene, however, ‘is evident from the fossils. It seems probable that while deposition was going on in Virginia, Maryland, and New Jersey during the Hocene period, North Carolina remained above water because of the complete absence, so far as known, of the Pamunkey series. In North Carolina the two Hocene formations have received the names of Trent and Castle Hayne. The Trent formation is developed best along the Trent river, though it occurs in patches over a large part of the state. This formation contains fossils not recognized in any of the Eocene formations of Virginia and Maryland, the most noticeable form being the large species of Ostrea georgiana. This form is unknown north of North Carolina, though it occurs farther south, and is found in great abundance at the famous Eocene locality of Shell bluff, on Savannah river, a few miles below TERTIARY EROSION INTERVALS—NORTH CAROLINA AND VIRGINIA 675 Augusta, Georgia. The Trent formation rests on underlying strata of Creta- ceous age along the Neuse and Trent rivers, and farther west is found in imme- diate contact with the underlying crystalline rocks of pre-Cambrian age. So far as known at present, the Trent formation has a wider inland distribution in North Carolina than any other Coastal Plain deposit. Isolated patches are known far to the west of the present ‘fall line,” one of these occurring a few miles from Raleigh, and another one near Spout Springs, in Harnett county, while still other areas have been reported from Moore county, in all of which they overlie directly the crystalline rocks. The second formation of the North Carolina Eocene has received the name of Castle Hayne because of its development in the vicinity of Castle Hayne on the northeast Cape Fear river. The lithologic characteristics of this formation . are, as in the case of the Trent, distinctly calcareous, with little or no glau- conite present, thus making it distinctly unlike the Eocene deposits of Virginia and Maryland. The fossils of this formation have not as yet received careful study, though Doctor Vaughan states that they form an entirely distinct fauna, unlike any known in South Carolina or in the Atlantic Coastal plain to the northward. The Castle Hayne formation outcrops in a very limited area in the southeastern part of the state, and wherever observed rests directly on Cretaceous strata belonging to the Peedee formation, and, further, it contains many Cretaceous shells that have been derived from these deposits. Several. articles have already appeared in which the commingling of the Cretaceous and Eocene species in this formation at Castle Hayne and Wilmington have been described. The distribution of the Trent formation in small isolated patches over sucha wide area indicates extensive post-Trent erosion, and the fact that we find the Castle Hayne formation resting on Cretaceous strata proves that at least a part of the intervening Trent strata must have been removed before the depo- sition of the Castle Hayne formation. Post-KocENE INTERVAL When we come to the Miocene we find that throughout the entire Coastal plain there is evidence of a considerable gap between the Eocene and the Miocene, though in Maryland it is scarcely possible to determine this uncon- formity except by overlap. In Virginia the same conditions exist, and there we find the Miocene gradually transgressing the Eocene to the westward until it comes to rest on the Piedmont crystalline rocks, entirely concealing the Eocene. In North Carolina the unconformity is much more pronounced, and there we find in many places Miocene beds resting on the Hocene deposits that occupy depressions in the irregular surface of the Cretaceous. Thus we find the Miocene resting on the Eocene in one locality, while a short distance away, at almost the same level, the Miocene is found in contact with the Cretaceous. The occurrence of Hocene deposits in pockets proves in a better way than in the case of the Maryland deposits an extensive erosion period separating the Eocene and Miocene. There is little doubt but that in the interstream areas of North Carolina beneath the covering of Pleistocene and Miocene strata there are many other patches of Kocene that have so far escaped observation. 676 PROCEEDINGS OF THE BALTIMORE MEETING MIOCENE FORMATIONS In Maryland the divisions of the Miocene are three in number—Calvert, Choptank, and Saint Marys—and these with slight modifications extend across the Potomac river, and have been recognized in Virginia by their character- istic fossils and also similar lithologic materials. Besides, in Virginia a new formation makes its appearance that does not appear at the surface in Mary- land, though it may be present in the eastern part of the state beneath the thick cover of Pleistocene materials. This is the Yorktown formation, so well exposed in the vicinity of Yorktown, on the York river. Of the three Miocene formations that extend across the Potomac river from Maryland, two of them— the Calvert and the Choptank—gradually disappear toward the southern part of the state, due to overlap or to non-deposition. The latter seems to be the case from what has been determined in North Carolina, where the Cretaceous is found immediately beneath the Saint Marys formation. In North Carolina we have three Miocene formations—the Saint Marys, which extends in an unbroken band from Maryland entirely across the state of Virginia; the York- town, which first appears as a surface formation in the vicinity of the York river, in Virginia, and which is continuous to the vicinity of the Neuse river, in North Carolina, though concealed in greater part in the interstream areas, and the Duplin, which occurs in isolated areas in the southern portion of the state and under similar conditions in the northern part of South Carolina. The Saint Marys formation, in the northern part of the state, rests on the Cre- taceous or the crystalline rocks. Near Halifax a stratum containing well pre- served molluscan shells is found in immediate contact with the decayed crys- tallines of the Piedmont plateau. Along the Tar river many exposures show the Saint Marys formation in contact with the lowest member of the Cre- taceous. North of the Neuse river, in North Carolina and all through Virginia, the Saint Marys formation seems to be continuous and is exposed in the valley of each of the major streams. South of the Neuse river it is doubtfully repre- sented in only a few localities, and there occurs as isolated patches of small extent. The Yorktown formation makes its appearance in the vicinity of the York river in Virginia, and from there extends southward as a continuous band to the Neuse river, and throughout this belt rests on the Saint Marys formation with no marked unconformity. Tracing the deposit over a considerable area, however, it is found to be unconformable, and the basal stratum, consisting of fragmental shells of beach origin, indicates an uplift of the region before the deposition of the Yorktown. The fact that we find the Saint Marys present so extensively to the north of the Neuse river and find only patches of it south- ward would seem to indicate its original distribution as a continuous forma- tion over a large part of the Coastal plain. Further, the fact that we now find the Yorktown resting directly on strata of Eocene age in the vicinity of Newbern, between the Trent and Neuse rivers, implies an erosion interval of considerable duration after the deposition of the Saint Marys and before the laying down of the Yorktown strata. The Yorktown, in its turn, south of the Neuse river, suffered much erosion prior to the opening of the Pliocene period, and perhaps since the Pliocene as well. The Duplin formation is found in isolated areas along the Cape Fear TERTIARY EROSION INTERVALS—NORTH CAROLINA AND VIRGINIA 677 river, in Duplin county, and southward. It is best known in Duplin county, North Carolina, where it is so well developed in the natural well near Mag- nolia. It is unknown in Virginia or in northern North Carolina, but has been recognized in several places in South Carolina. No doubt it is of the same age as some of the beds in the vicinity of Darlington and on the Peedee river in South Carolina. The Duplin formation, disappearing northward near the line where the Yorktown appears, might suggest their equivalency were it not for the fact that the Duplin strata contains a much more recent fauna. PLIOCENE FORMATION. Marine Pliocene deposits are unknown in Maryland and Virginia, though certain beds in the vicinity of the Dismal swamp in Virginia have been referred to this period. The evidence gained during the last year, however, seems to prove conclusively that the beds referred to the Pliocene in that sec- tion are in reality Pleistocene. Marine Pliocene beds, however, do appear in the southern portion of North Carolina. They are well developed along the Cape Fear river at Neills Eddy landing and Walkers bluff and in the vicinity of Croatan, south of the Neuse river. Also along the Waccamaw river, in South Carolina, the Pliocene is well developed, overlying the Peedee formation -of the Cretaceous. The Cape Fear River deposits have been referred to the Waccamaw formation, and the fossiliferous strata near Croatan to the Croatan formation. It is not improbable that the latter deposits may eventually be referred to the Pleistocene, though they contain certain fossils that have usually been regarded as distinctly Pliocene types. At Neills Eddy landing and Walkers bluff the Pliocene is found in contact with the Cretaceous. Fos- sils of Peedee age are contained in the strata immediately underlying the Pliocene beds at the latter place. Summing up the evidence, we find that each one of the Tertiary formations in North Carolina is separated both from the underlying and the overlying formations by an erosional unconformity, and each formation is found in one place or another in immediate contact with the Cretaceous. In Virginia the unconformities are less noticeable. RELATIONS OF THE NORTH CAROLINA TERTIARY FORMATIONS One of the most striking things brought out in the recent work is the pres- ence of the sharp line of demarcation occurring in the vicinity of the Neuse river. We seem to have evidence in almost every period of uplift during the Tertiary of different conditions prevailing south of the Neuse river than to the northward. Each of the Tertiary formations is almost entirely confined to one side of the river. The evidence obtained in the recent investigations in North Carolina seems to indicate that in that state we have a sharp change both in the character of the fossils and in the lithology between the Coastal Plain region to the northward and that lying to the south. The northern part of North Carolina in almost every particular, so far as the Tertiary deposits are concerned, seems to properly belong to the region lying to the northward— Virginia and Maryland—while southern North Carolina, south of the Neuse river, forms an essential part of the southern Atlantic Coastal plain, extending southward to Florida and bordering the gulf of Mexico. Beside the evidence 678 PROCEEDINGS OF THE BALTIMORE MEETING already given to support this view, we have also the increasing or decreasing prominence of the strata of different periods as we cross the Neuse River valley. North of the Neuse river the Eocene is wanting for a considerable distance, and when it appears in the northern part of Virginia presents a dis- tinctive glauconitic character and extends northward through Maryland, but with a thickness scarcely exceeding 200 feet. South of the Neuse river the Eocene appears, presenting a calcareous phase, and gradually increases in importance until in the Gulf region, particularly in Alabama, it becomes of very great importance. The Miocene formations throughout Maryland, Vir- ginia, and the northern part of North Carolina are especially well developed and have received much attention. South of the Neuse river, in North Caro- lina, they are still represented, but with greatly decreased importance, and throughout the Gulf region the Miocene is distinctly subordinate in thickness and areal extent to the Hocene. The Pliocene period also shows similar char- acteristics. As already stated, the marine Pliocene, so far aS we know, is entirely absent north of the Neuse river, but southward it appears in isolated patches in North Carolina, and also is represented southward to the gulf and becomes increasingly more important. “HATTERAS AXIS” Earlier workers have discussed the so-called ‘‘Hatteras axis” separating the Coastal plain in two portions, though the evidence was somewhat meager. The study of the Tertiary strata of North Carolina furnishes data for drawing this line of separation between the North and South Atlantic Coastal plains much more definitely. In general this line is followed by the Neuse river, as stated on a previous page. This line may be considered as an axis, in that denudation and sedimentation during each of the Tertiary periods were unlike on the two sides, and in most instances denudation south of the axis seems to have occurred at approximately the same time that deposition was taking place to the northward, and vice versa. The faunal studies which are now being carried on are expected to throw additional light on this problem. Then was presented orally by the senior author CHARACTER AND STRUCTURAL RELATIONS OF THE LIMESTONES OF THE PIEDMONT IN MARYLAND AND VIRGINIA BY EDWARD B. MATHEWS AND J. S. GRASTY [Abstract] A study of the small bodies of crystalline limestones and marbles found along the western edge of the Piedmont from Pennsylvania to North Carolina shows that their occurrences mark the tops of tightly compressed anticlines. The deposits on either side are usually metamorphosed voleanics—flows and tuffs— which in the normal section lie far beneath the limestones. The areal distribu- tion, contacts, and structural lines point to a strong overthrust fault of wide extent. This paper was discussed by J. Barrell. TROPIDOLEPTUS FAUNA IN MARYLAND CHEMUNG 679 RECURRENCE OF THE TROPIDOLEPTUS FAUNA IN THE CHEMUNG OF MARYLAND} BY CHARLES K. SWARTZ Contents Page JRACULRENOS “Ot TRIOS Saeco 6 cae Gidin BO CM OIeNOIO 6 6 BLN O0 O-CEONE COND ECRCIA CRC nCRT = hiner Nr aaa renee 679 EASTON CA ee WAC Wee sacha cic eheton. aeener ore ieuelene roretel ey elicnsnecs oie Toels Cieliontrsl Ol w eialars ee swe e hha ee 679 FEM OROSTCAIEISE (HU CINCO es ene etey pees ore or rer eb erie sits ia Fe renelicn cuaclajiel eve hece se) sivelieM ewe ale (eiteaoilsi clara ci atels ale 680 SECMOMSmeASEMOLE VWallSe Mm OUMMbalmMame s cietsckcre serene eis sialecers crcl ee creas eyecslelie 6 ei's'e 6. 0c wile THeOS2 Section 1% miles south of Round, West Virginia.................-....--... 682 SECUONMWEST BOI. OKOMOKO may eicunyerciete rst oh suoious ober sievet on siicis |sieveere iclferSiclievis: ohelisliel (aisle) Se je%s16 «+ 682 SECHOMMAWESTEO La DWI 2 Wrernyeeterecsiobercuens eiece elie oi erela te) sie siceliele lis Vere: ciclierie|(oreie: srreltereile) 6)’ 682 IMIOTEMCASTCE YP ISCCEIONS s ccrstencte con aisier austere ars eitets eels Sia levaele aelelsiel ea stele 8 See 8, 6 6's 8s 683 SICHewMEe WESE CGE WHS mtObeMishling 665000 onndoGoooUK OOo OD oO addon oO OOD OOD BOGS 683 | SechioneMeadrwAllesamyarehOvierer..mere) orsiercakeksl oie sisi: Sreeiebeuenetel ell sire revicksiccilellssepere) eeieile, © 006 683 SCCUMOMMM Es Ta NOES yes a auar eu aie veers wie renen celal sicese ovens, ofascuehoue lee e cones nelle, eitei erielfeverteuieon8 683 CoOnRLelMHoOneOl, UIEMVATIOUS. SECLIONS).c5 se ccs ciel ie. ole ere s\lenele le see 6) eves, 6 cis) eee es © eee ee 684 Correlation with the Upper Devonian of New York... .2..- 0-260: scsee6sc005% 50 685 Geographical range of the genera Dalmanella and Douvillina in Maryland......... 685 (© INCU USOT Ses irebroirsie (ohare ciate i Suehis sovejin or autos Sila (outa: witetatenoperienen eel wigeWor eaters mute ‘ove baieleaten eveiene, shape hs sive 686 RECURRENCE OF FAUNAS The occurrence of a fauna characteristic of one geological formation within the limits of another formation is a phenomenon of much interest, since it affects the problem of the correlation of geological horizons. Barrande first clearly pointed out the possibly of the occurrence of one fauna in the midst of another in his now famous doctrine of colonies. While his inter- pretation of the sections studied by him has proved erroneous, the principle enunciated has been of great importance, especially in suggesting the concep- tion of the simultaneous existence of independent faunas in different areas. Williams? subsequently applied the same principle to the Upper Devonian strata of New York, and his work has been extended by many other students of the problem. Four recurrences of the Hamilton fauna, termed by Williams the T'ropidolep- tus carinatus fauna, are recorded by him in the Upper Devonian strata of New York above the summit of the Hamilton formation.? The uppermost of these horizons lies within the Chemung of that state. The existence of similar recurrent faunas in the Chemung of Maryland has recently been observed by the author, and he believes that the facts observed and certain conclusions based upon them, may be worthy of communication. A brief historical statement will be helpful in understanding the discussion. HISTORICAL REVIEW The Upper Devonian of Maryland presents two well defined facies, a lower marine division and an upper division having the characteristics of the Catskill of New York. 1 Published by permission of the Director of the Maryland Geological Survey. Manu- seript received by the Secretary of the Society June 5, 1909. 2 Proceedings of the American Association for the Advancement of Science, vol. xxx, 1881, p. 186. U. S. Geological Survey, Bull. no. 3, 1884. 3 Journal of Geology, vol. xv, 1907, pp. 108-110. 680 PROCEEDINGS OF THE BALTIMORE MEETING The lower marine strata are known as the Jennings formation. This forma- tion has long been recognized as equivalent, in a general way, to the Genesee, Portage, and Chemung of New York. The Jennings of Maryland has been studied by Professor C. S. Prosser, who has prepared a monographie treatment of the subject to be issued in the forthcoming volume of the Maryland Geo- logical Survey, upon the Devonian of Maryland. An extended and admirable study of the fauna was made by Dr J. M. Clarke, of Albany, New York, whose work will appear in the same volume. A brief summary of the results ob- tained by these workers was published by Professor Prosser in the Journal of Geology in 1901.4 d The author wishes to acknowledge his indebtedness to these two gentlemen, with whose work he has been acquainted, in advance of its full publication, in the prosecution of his own studies. A full statement of their results will ap- pear in the volume mentioned. The author subsequently showed that a fauna similar to the Ithaca fauna of New York occurs in the Portage of Maryland, and that this is succeeded by a fauna of marked Hamilton type, frequently abounding in TJ'ropidoleptus carin- atus, which occurs in the Portage below the strata containing the typical Che- mung species.® At the time of the publication of the paper referred to, the occurrence of the Tropidoleptus carinatus fauna above the base of the Chemung fauna had not been observed by the writer and his associates.® During the past summer T'ropidoleptus carinatus and associated Hamilton species have been observed about 600 feet above the base of the Chemung fauna. It is to record this occurrence that the present communication is made. The author wishes to acknowledge his great indebtedness to Professor D. W. Ohern, to whom he is under obligations for constant and most intelligent co- operation in the prosecution of this entire investigation, and to Dr T. P. May- nard, who has assisted in measuring certain of the sections described. Before considering the fauna it will be helpful to discuss the lithological sequence in the Upper Devonian of Maryland. LITHOLOGICAL SEQUENCE The Jennings of Maryland embraces nearly 5,000 feet of strata. At the base, in the west, are the black shales of the Genesee member. Above this succeed argillaceous shales alternating with thin sandstones, the percentage of sand- stone increasing in the upper part of this zone. These shales and interbedded flaggy sandstones bear the Naples fauna as in New York. They are succeeded by slightly more arenaceous sediments bearing a profuse development of the Ithaca fauna characterized by the dominance of Spirifer penatus var. posterus Hall and Clarke. Overlying the latter appear more arenaceous sediments con- taining prominent conglomerates in the east and bearing a profuse fauna of distinctly Hamilton type, dominated by the presence of T'ropidoleptus carinatus 4 Journal of Geology, vol. ix, 1901, pp. 419-420. 5 Sournal of Geology, vol. xvi, 1908, p. 328. 6 Professor Prosser had observed the occurrence of Tropidoleptus carinatus in his study of the Jennings, but had not determined its horizon with respect to the succession of faunas here discussed. JENNINGS FORMATION, WESTERN MARYLAND 681 Sections of Jennings Formation Western Maryland Worizontal Scale linch=2miles Vertical Scale (inch =lovo Feet A\titude above base of Jenni bake ts) 0Q' Allegany cumberland Westof Green Little Great FEN EE Ce Round Okonoko Ridge Orleans cCacapn Springs Eastof Okonoko Nann Figure 1.—Sections of Jennings Formation, Western Maryland 682 PROCEEDINGS OF THE BALTIMORE MEETING i, Conrad and Spirifer mesacostalis Hall. Above these succeed typical Chemung sediments containing a Chemung fauna. The percentage of sandstone in- creases in general in ascending in the section. In the central part of the area, at an altitude of about 600 feet above the base of the Spirifer disjunctus fauna, appears a zone usually conglomeratic and containing massive sandstones eastward, which bears at places a profuse development of J'ropidoleptus carinatus and associated species of Hamilton type. This is in turn succeeded by the Spirifer disjunctus fauna. The T'ropi- doleptus carinatus fauna is thus a recurrent fauna of Hamilton type lying within the Chemung fauna of Maryland. The occurrence of this recurrent fauna in the various sections will now be discussed. SECTIONS EAST OF WILLS MOUNTAIN SECTION 1% MILES SOUTH OF ROUND, WEST VIRGINIA This fauna was first observed on the farm of John Will Smith, about 1% miles south of Round, West Virginia. At this point the strata occupy the axis of a syncline and are nearly horizontal. A massive sandstone bearing Camaro- techia congregata (Conrad), Spirifer mesacostalis Hall, etcetera, occurs about 1,100 feet below the top of the section. Six hundred feet above the latter Spirifer disjunctus was found. This horizon is overlaid by heavy red sand- stone cropping out on the hillsides. The summit of the hill is formed by mas- sive gray sandstones and conglomerate, which bear a profusion of T'ropidolep- tus carinatus. The following species were collected at this horizon: Tropidoleptus carinatus (Conrad) ab. Spirifer marcyi Hall var. ec. Ambocelia umbonata (Conrad). Rhipidomella vanuxemi Hall. Camarotechia sappho Hall. Tropidoleptus carinatus is profuse and typical. Spirifer marcyi is a variety with an unusually high area and massive appearance, but admits of no doubt of the identification. All of the species are characteristic of the Hamilton. SECTION WEST OF OKONOKO A similar conglomerate appears at an altitude of 2,650 feet above the base of the Jennings in the section on the Western Maryland railroad west of Okonoko, north of the Potomac river, on the west side of Green ridge. Spirifer dis- junctus appears in the section at 2,000 feet above the base of the Jennings. The following faunule was secured at about 2,670 feet: Tropidoleptus carinatus (Conrad) Spirifer marcyi Hall Ambocelia wmbonata (Conrad) SECTION WEST OF PAWPAW Numerous excellent exposures occur in the vicinity of Pawpaw. A very massive sandstone, slightly conglomeratic, forms the summit of the Devils Nose. On the west slope of the mountain, along the Baltimore and Ohio rail- TROPIDOLEPTUS FAUNA IN MARYLAND CHEMUNG 683 road, a lower massive conglomerate is exposed, holding essentially the same position as the Tropidoleptus-bearing zone west of Okonoko. It bears T'ropi- doleptus carinatus. This species, and others found in the preceding sections, were observed at numerous points in the vicinity on the strike, lying about 500 to 700 feet above the base of the Spirifer disjunctus fauna. The latter is constantly underlain by the lower Tropidoleptus fauna, below which appears the Ithaca fauna. It is thus possible to trace a continuous horizon, which is very conglomeratic in the east, much less so in the west, and which bears Tropidoleptus carinatus lying at an altitude of about 2,500 to 2,700 feet above the base of the Jennings. MORE EASTERLY SECTIONS A persistent and massive conglomerate appears at approximately the same altitude in the sections farther east. They have not yet been studied with respect to the occurrence of T'ropidoleptus carinatus, but it is believed that they represent the same horizon.’ SECTIONS WEST OF WILLS MOUNTAIN SECTION NEAR ALLEGANY GROVE When we pass west of Wills mountain the sections show marked faunal and lithological changes, though they are but a few miles distant from the most westerly sections previously described. The best section of the region is near Allegany Grove, about four miles south- west of Cumberland, along the Cumberland and Potomac, and the Georges Creek and Pennsylvania railroads. The lower part of the section consists largely of argillaceous shales. At an altitude of about 800 feet above the base of the Jennings, Camarotechia sp. was found in somewhat more arenaceous sediments. At an altitude of 1,360 feet Spirifer disjunctus occurs. At 1,560 feet massive sandstones develop. The 7'ropidoleptus carinatus fauna is found in these strata a short distance south of the railroad. At 1,900 feet a heavy conglomerate appears associated with gray and brown sandstones. At 2,600 feet is a second massive conglomerate, which is revealed only by fragments in the section on the railroad. Several other less prominent conglomerates are seen above this. The Catskill appears at the east end of the tunnel at an alti- tude of 3,000 feet above the base of the section. SECTION NEAR ELLERSLY At Hllersly, 614 miles northeast of the preceding section on the strike, a pro- fuse development of Dalmanella tioga (Hall), Spirifer disjunctus, and other characteristic Chemung forms appears at an elevation of about 1,300 feet. The same zone may be traced southwestward nearly to the Potomac river, showing that the Spirifer disjunctus fauna appears at about 1,300 or 1,400 feet above the base of the section. Tropidoleptus carinatus was observed abun- dantly at a number of points southwestward on the strike in what appears to be the massive sandstone occurring at 1,560 feet altitude in the Allegany 7 Since the above was written the Tropidoleptus carinatus fauna has been found at the appropriate horizon in the section near Mann, east of Sideling Hill. 684 PROCEEDINGS OF THE BALTIMORE MEETING Grove section. This fauna therefore lies above a strongly developed Chemung fauna containing numerous Spirifer disjunctus Sowerby, Dalmanella tioga (Hall), Pterinea chemungensis Conrad, etcetera. CORRELATION OF THE VARIOUS SECTIONS An examination of the various sections (see accompanying chart) shows that there are certain persistent horizons which may be traced throughout the region. The black shales of the Genesee form the base of the Jennings in the western sections, thinning out and disappearing eastward. Above the latter, or at the base of the Jennings in their absence, occur shales and interbedded flaggy sandstones resembling the Sherburne of New York and carrying the Naples fauna, as in that state. These are overlain by shales containing the Ithaca fauna in the eastern sec- tions. This fauna disappears west of Green ridge. These strata are succeeded by the lower Tropidoleptus carinatus (Spirifer mesacostalis) zone,’ characterized by a profusion of Tropidoleptus carinatus (Conrad), Spirifer mesacostalis Hall, and associated species of Hamilton type. This zone is conglomeratic in the east, but is represented by sandstones west- ward, where the conglomerates disappear. The Spirifer disjunctus fauna overlies the preceding, being found about 1,800 to 2,000 feet above the base of the Jennings in the eastern sections and at about 1,300 feet above the base of the formation west of Wills mountain. The Tropidoleptus fauna recurs at an altitude of about 2,600 to 2,700 feet above the base of the Jennings in the middle part of the area, associated with conglom- erates and sandstones which become less massive westward. This fauna can be traced at about the same altitude from the sections east of Pawpaw, West Virginia, to the vicinity of Round, West Virginia. A similar fauna occurs about 200 feet above the base of the Spirifer disjunctus fauna and about 1,500 feet above the base of the Jennings, west of Wills mountain. It is, however, not possible at present to correlate the latter confidently with the upper Tropido- leptus zone of the earlier sections. : The upper part of the section contains massive conglomeratie sandstones. The Jennings is overlain by red strata of Catskill type. J. J. Stevenson, in his vice-presidential address before the American Associa- tion for the Advancement of Science,’ calls attention to the existence of two well defined conglomerate horizons in the Upper Devonian of Pennsylvania and adjoining states which he correlates over wide areas. He terms the lower of these the Allegrippus and the upper the Lackawaxen conglomerate, names in- troduced by I. C. White. He believes that they are persistent over large areas and that they can be recognized in regions immediately adjoining Maryland. A eareful examination of the section shows that in Maryland the problem is much more complex. There are not two, but many conglomerates in the sec- tion. These conglomerates are very variable in their local development. The conglomerates of the east may be replaced by sandstones in the west, while other conglomerates develop at higher horizons. It thus seems to the author 8 See discussion of this fauna, Journal of Geology, vol. xvi, 1908, p. 308. ® Proceedings of the American Association for the Advancement of Science, vol. xl, 1891 (1892), p. 219. TROPIDOLEPTUS FAUNA IN MARYLAND CHEMUNG 685 to be very hazardous to attempt a correlation of the conglomerates over a large area by their position in the section without faunal evidence, which has not yet been secured. CORRELATION WITH THE UPPER DEVONIAN OF NEW YORK The comparison of the sequence of the Upper Devonian strata in Maryland, as shown by the above sections, and that in New York, recorded by Williams,” shows a striking similarity. SEcTION IN MARYLAND Section aT IrHaca, NEw York Sandstones and shales Upper conglomerate, 25-50 Fall Creek conglomerate, 0-10 Sandstone and shales, 700-800 Wellsburg sandstone, 600-650 Upper Tropidoleptus carinatus Zone Tropidoleptus carinatus Zone Shales and sandstone, 500-700 Cayuga shale, 600 Lower Tropidoleptus carinatus Zone Enfield shale (with recurrent Tropido- (Spirifer mesacostalis Zone), 300-600 leptus fauna), 550-800 Shales and sandstone, Ithaca fauna Ithaca shale Shales and sandstone with Naples fauna Sherburne flagstone with Naples fauna Genesee, absent in east Genesee The sequence of the faunas is the same, both in New York and in Maryland, while there is a marked similarity in the lithological features. The close simi- larity of the sections, both lithologically and faunally, is striking and indicates that the Upper Devonian of Maryland and New York were laid down in a common basin and under similar conditions. GEOGRAPHICAL RANGE OF THE GENERA DALMANELLA AND DOUVILLINA IN MARYLAND In examining the distribution of the species of the Chemung fauna certain features are to be noted. Species of the genus Dalmanella are very rare east of the Wills Mountain anticline. Up to this time the author and his associates have not observed a single specimen of. Dalmanella east of Wills mountain, and but a single valve has been reported from that region by others. West of Wills mountain, on the contrary, they are abundant. Again, species of Dou- villina are not common east of the same locality, while they are very abundant west of it. Spirifer disjunctus, however, is abundant throughout the area. A somewhat comparable condition seems to exist in New York, where Wil- liams" does not cite any species of Dalmanella from the eastern part of the state in his recent paper on the genus Dalmanella. The reason for these facts is not clear. Wills mountain is the high western arch of the Alleghany moun- tains. The marked difference in the fauna east and west of it suggests the possibility that the arch may have begun to rise early in Upper Devonian time, forming a submerged barrier at that time. This is a mere suggestion, how- ever, and needs further confirmation before being worthy of acceptance. The facts given may be summarized in the following conclusions: 10 Williams : Devonian section of Ithaca, N. Y. Journal of Geology, vil. xiv, p. 579. “4 Proceedings of the U. S. National Museum, vol. xxxiv, 1908. 686 PROCEEDINGS OF THE BALTIMORE MEETING CONCLUSIONS Two recurrences of the Tropidoleptus carinatus fauna are recorded in the Upper Devonian of Maryland, one in the upper part of the Portage and one about 600 feet above the base of the Chemung, in the central part of the Upper Devonian area. A marked similarity exists in the succession of faunas as well as in the lithological features of the Upper Devonian strata of Maryland and New York, suggesting that these strata were laid down in one basin of deposition under Similar conditions. Certain differences in the faunas east and west of Wills mountain suggest the possibility of the existence of some form of a low barrier in this locality in Chemung time. GHOLOGICAL DISTRIBUTION OF THE MESOZOIC AND CEHENOZOIC HCHINODER- MATA OF THE UNITED STATES: BY W. B. CLARK AND M. W. TWITCHELL [Abstract] Echinoderm remains are found in America in the deposits of every period from the Triassic to the Recent, but are by far the most significant in those of Cretaceous and Eocene age. In several formations they are among the most valuable of diagnostic fossils, while at a few localities they occur in vast numbers. Comparatively few J'riassic forms have been found. The most common are crinoid stems, representing the genera Pentacrinus and Hncrinus, the former found in both the Lower Triassic of Idaho and the Upper Triassic of Cali- fornia, and the latter confined to the Upper Triassic of California. The echinoids are represented by two species of Cidaris, which are confined to the Upper Triassic of California. In addition to these a few indistinct casts, among them a small, poorly preserved starfish, which has been questionably assigned to the genus Aspidura, have been found in the Lower Triassic of Idaho. The Jurassic echinoderms are somewhat more numerous and varied, al- though they do not constitute an important element in the fauna. As in the Triassic, the most common forms belong to the genus Pentacrinus, column joints having been found in Nebraska, South Dakota, Wyoming, Colorado, Idaho, Utah, and California. The asteroids are represented by both the Ophiuride and Stelleridz, specimens having been found in Wyoming, South Dakota, and Utah. The echinoids are much more fully represented than in the Triassic. Several genera have been recognized, among them Cidaris, Hemicidaris, Pseudodiadema, Stromechinus, Holectypus, and Pygurus. The specimens are in the main poorly preserved and are rarely numerous. The first four genera occur only in California, being found in both the Lower and Middle Jurassic. One species of Holectypus occurs in Texas and another in Montana, while Pygurus has only been found in Texas. 1 Published by permission of the Director of the U. S. Geological Survey. A mono- graphic study of the Mesozoic and Cenozoic Echinodermata of the United States has been made by the authors. Manuscript received by the Secretary of the Society May 27, 1909. RES fio DISTRIBUTION OF MESOZOIC AND CENOZOIC ECHINODERMATA 687 The Cretaceous echinoderms are very numerous in certain areas. A great variety of types is represented and the material is oftentimes splendidly pre- served. Many of the species are narrowly limited in geological range and therefore are important as type fossils. The erinoids are represented by Uintacrinus, Pentacrinus, and Rhizocrinus, this first genus having afforded a great number of remarkable specimens in the Niobrara chalk of Kansas. Springer has made this material the subject of an elaborate monograph, and most of the great museums of the world con- tain beautiful specimens from the now famous locality in Kansas. The asteroids contain representatives of both the Ophiuride and the Stel- | leridz, the genera Ophioglypha, Astropecten, Goniaster, Pentagonaster, and Pentaceros being found. The material comes from widely separated areas in New Jersey, Texas, and Wyoming. The echinoids are very numerous, both the regular and irregular types being well represented. The Lower Cretaceous deposits of Texas contain vast num- bers of individuals at several horizons and in certain areas, while the Upper Cretaceous of the Atlantic and eastern Gulf coasts, particularly in New Jersey, North Carolina, Alabama, and Mississippi, although less fully characterized by its echinoid fauna, affords many forms. The western Interior and Pacific Coast Cretaceous contains a much smaller representation of echinoid types. Among the Lower Cretaceous genera found represented more particularly in Texas are: Cidaris, Leiocidaris, Salenia, Hypodiadema, Goniopygus, Pseudo- diadema, Diplopodia, Heterodiadema, Cottaldia, Pedinopsis, Orthopsis, Cypho- soma, Micropsis, Holectypus, Pyrina, Ananchytes, Holaster, Enallaster, and Hemiaster, the last furnishing many species. Outside of Texas very few Lower Cretaceous echinoids have been recognized, the Horsetown beds of California containing a few forms. The Upper Cretaceous of the Atlantic and Gulf coasts has afforded repre- sentatives of the following genera: Cidaris, Salenia, Pseudodiadema, Copto- soma, Psammechinus, Echinobrissus, Trematopygus, Botriopygus, Cassidulus (many species of which have been recognized), Catopygus, Hchinanthus, Ananchytes, Cardiaster, Hemiaster, and Linthia. Much the larger number of forms have been found in the New Jersey Cretaceous, especially the Vincen- town limesand bed of the Rancocas formation, which is regarded as probably of Danian age. The western Interior and Pacific Coast areas contain few representatives of the echinoids, most of the species belonging to the genus Hemiaster. The Hocene deposits have afforded a considerable number of echinoderms, but they are less numerous than in the Cretaceous. They are found at various Eocene horizons on the Atlantic and Pacific coasts, but are most numerous and characteristic in the South Atlantic and Gulf Eocene, where they occur in large numbers. Nearly all of the echinoderm materials belong to the group of — the echinoids, although representatives of the Crinoidea, Asteroidea, and Holothuroidea have been found. Among the echinoid genera recognized are Cidaris, Celopleurus, Echinocyamus, Sismondia, Scutella, Mortonia, Breynella, Echinolampas, Clypeaster, Cassidulus, Hemipatagus, Brissopsis, Ditremaster, Linthia, Schizaster, Ewpatagus, Macropneustes, Sarsella. The Oligocene strata of the South Atlantic and Gulf areas have not been in many instances satisfactorily delimited from the Eocene, so that the age of LXIV—BULL. GEOL. Soc. AM., Vou. 20, 1908 688 PROCEEDINGS OF THE ‘BALTIMORE MEETING some of the echinoid material can not be with certainty determined. Among the known Oligocene genera of the South Atlantic and Gulf areas are Cidaris, Sismondia, Laganum, Amblypygus, Oligopygus, Cassidulus, and Hupatagus. The great majority of the forms come from Florida. The Oligocene deposits of California have also furnished specimens of Cidaris. The Miocene deposits of both the Atlantic and Pacific coasts have afforded a considerable number of echinoderms, chiefly echinoids. The Atlantic Coast Miocene contains Ophioderma (?), Cidaris, Celopleurus, Psammechinus, Scutella, Encope, Mellita, Agassizia, Brissus, Plagionatus, and Hehinocardium. The Pacific Coast Miocene, on the other hand, has furnished Asterias, Am- phiura, Cidaris, Scutella, Clypeaster (?), Astrodapsis, and Linthia. The Pliocene deposits contain very few echinoderms. On the South Atlantic coast from the Carolinas southward a few forms have been recognized, among them Strongylocentrotus, Encope, and Clypeaster. On the Pacific coast Astro- dapsis, Scutella, and Schizaster (?) are found. The Miocene and Pliocene echinoids of the Pacific coast have been found to be of more than ordinary value in the determination of geologic horizons. This is due to their limited geologic range and to the fact that, where present at all, they are usually abundant and well preserved. The Pleistocene deposits likewise have furnished very few echinoderms, and those for the most part of species living in the adjacent seas. Among those recognized from the Atlantic border have been Asterias, Asteracanthion, Strongylocentrotus, Mellita, Moira, and T'axopneustes. On the Pacific coast, on the other hand, several species of Strongylocentrotus and WScutella are found. The paper was discussed by John M. Clarke and W. B. Clark. The next paper read was AGH OF THE GASPEE SANDSTONE* BY HENRY SHALER WILLIAMS Contents Page Former explanation of mixture of Hamiltonian and Oriskanian species in fauna of Gaspé sandstone (York River beds) 2.2.0.0. 5.00% c0. 33 ss ses aes 688 Reasons for reviewing former interpretations. 92s... .2.0.. +s seie =ele enna 689 SUMMary Of EVIGEMCE: 5.0) W eis io ops caeiel opens oily cis olla, wl due) oa evera Rueiere ee SEO er 693 @OTEUSTON SS, 2 Annual Report of the Geological Survey of Canada, n. s., vol. vii, 1896, pp. 155/- 156). 3 American Geologist, vol. xxvii, April, 1901, p. 253. 4 Vice-Presidential address, American Academy for the Advancement of Science, 1899, p. 16. 5 Canadian Record of Science, vol. ix, 1903, pp. 56-57, based upon letter written by H. S. Williams to Dr F. D. Adams, dated May 16, 1902. 6 Letter of H. S. Williams to Dr F. D. Adams, dated February 23, 1906, reporting on the fossils collected from Coté Saint Paul: the letter states that the fossils there found were “characteristic of the Hamilton formation as seen in Schoharie and Albany counties, New York state,’’ adding that the fossils suggested ‘‘a sea opening for this region as late as the time of deposition of the Hamilton formation,” and, further, “This discovery at Coté Saint Paul, if its origin upon the spot is certain, gives positive proof of the exist- ence of marine conditions up to the time of living of the typical Hamilton fauna,”’ 690 PROCEEDINGS OF THE BALTIMORE MEETING These faunas run up at least into early Oriskanian in the Chapman fauna of Aroostook county and the Moose River sandstones of Somerset county, Maine, and in Gaspé in the Grande Gréve limestones, as shown by Doctor Clarke. Near Montreal, on the north side of the Connecticut-Saint Lawrence trough, there is evidence of the Helderberg in the Lower Saint Helens fauna and, as I reported in 1902,’ the Upper Saint Helens reaches the Oriskanian age. Limestones at Owls head, lake Memphremagog, and farther east at river Chaudiére contain fossils of Onondagaian age, thus bringing conclusive proof of marine waters in this eastern region to an epoch as late as Onondagaian. The Upper Saint Helens Island fauna is also in evidence with its species of strongly Hamiltonian aspect and the block of limestone from the island of Coté Saint Paul, which I originally thought contained only Hamiltonian species. Thus the evidence seems to be cumulative in favor of Doctor Clarke’s hy- pothesis of Hamiltonian age for the Calecareous beds at the base of the Gaspé sandstones. The opinion has been growing with me, however, that this inter- pretation can not be correct, and recently I made a thorough review of the facts with the results which I am about to set forth. The reason for applying the test to the Gaspé series is because there the sequence is most complete, but the decision will apply to all the associated faunas in which the mingling of faunas appear. Doctor Clarke has reported forty-nine species from the Gaspé sandstone ; the marine invertebrates are almost all from the Calcareous beds at the base of the 7,000 feet Gaspé sandstones, which apparently follow conformably on the Grande Gréve limestone. In order to distinguish the beds and the fauna from the succeeding sand- stones and conglomerates holding plants and brackish water types of fish, I have called these basal beds the York River beds, from the river emptying southeast of the small peninsula, where the main part of the fossils were obtained. The number of species given names of Hamilton species and described as having Hamiltonian affinities exceeds the number of strictly Oriskanian spe- cies, which is the ground mentioned for calling the beds Hamiltonian in age. I have critically examined the list, and am inclined to think that Doctor Clarke has given undue weight to number of separate specific names, and has overlooked the intrinsic testimony of the larger number of individuals belong- ing to a few species of undoubted Oriskanian age. There are forty-nine species in the list, but the four vertebrates and the Tropidocaris are not reported as associated with the marine fossils of the York River beds. There are seventeen names either new species or generic names without identification of species, thus leaving but twenty-seven species strictly identified with the species of known faunas. Of the twenty-seven positively identified species, fourteen are listed in faunas of known Hamiltonian age, and thirteen have been listed in faunas of Oriskanian age. With this restriction the Hamiltonian species still have the advantage in number. But of the fourteen positively identified Hamilton spe- cies only three are indicated as common in the fauna; all the others, therefore, may be classed as not dominant in the York River fauna. 7 See Canadian Record of Science, vol. ix, 1903, pp. 56-57. o AGE OF THE GASPE SANDSTONE 691 The three said to be at all common are Cyrtina hamiltonensis, Nuculites triqueter, and T'ropidodiscus rotalinea. The fact that Cyrtina heteroclita, certainty a very closely related species, ranges throughout the Lower and Middle Devonian of Hurope diminishes the value of Cyrtina hamiltonensis as witness of the Hamiltonian age of the fauna. Oyrtima dalmani, which ranges lower than Oriskany, can not be regarded as far removed from the Hamilton species. Nuculites triqueter can not be regarded as of much significance in making a close identification of the fauna because of its wide range as a genus, and also because of the exceedingly unsatisfactory characters it presents for specific identification, as shown by the fact that Professor Hall in the elaborate volume on the Lamellibranches of the Devonian of New York state in the preliminary publication placed four figures of the plate illustrating the genus in the newly described species N. nyssa, which in the final publication three years later he listed as WN. triqueter. This leaves only one dominant species of the fauna positively correlating it with the Hamiltonian fauna. On the other hand, the following species of Oriskanian age are in the list: Rensseleria ovoides, Eatonia peculiaris, Leptocelia flabellites, Orthothetes hecraftensis, Chonetes hudsonicus, Chonostrophia dawsoni, Chonostrophia com- planata, and Phacops correlator, five of which are common or abundant spe- cies in the York River fauna, and all of them are dominant Oriskany species. Two other species, namely, Spirifer gaspensis and Leptostrophia blainvillei. are also dominant species in these York River beds at Gaspé, and though not reported outside of the eastern province are always found associated with well known Oriskany species. Thus ten of the thirteen positively identified species are dominant species in the particular fauna at Gaspé, and are also dominant species in Oriskanian faunas wherever they occur. I can not escape the conviction that taking the list as given by Doctor Clarke the dominant species of Oriskanian affinities present a much stronger testimony as to the age of the fauna than do the Hamiltonian species, which although greater in number of species are poorly represented in the fauna. But suppose we waive the differing values of the specific units in making up the average, granting for the argument that the evidence is as strong for the Hamiltonian as the Oriskanian elements of the fauna, is there any @ priori reason why we must assume that the Oriskanian element lived on in this one locality until the Hamiltonian epoch? May not the same facts be interpreted as indicating the early appearance in the Oriskanian epoch of traces of the species which elsewhere did not appear till the Hamiltonian epoch? Not only the intrinsic evidence of the fauna bears out this conclusion, but the geograph- ical evidence supports the same view. The argument for Hamiltonian age is supported by the like association of species in the upper of the two Saint Helens Island faunas, where are found associated with species of Oriskany type other species of decided Hamiltonian type. This argument, however, is offset by the fact that the Coblenzian and other Lower Devonian faunas of Europe show a similar combination of species which in North America are either characteristic Lower Helderberg-Oriskany types or else are characteristic Middle Devonian types. If we suppose the Gaspé basin to have been in open communication with the sea eastward, is it 692 PROCEEDINGS OF THE BALTIMORE MEETING not as easy to account for the forerunners of the Hamilton species in the Oriskanian of America as in the Lower Coblenzian of Europe? There is, moreover, positive difficulty in accounting for the combination of species in the Hamiltonian epoch of North America. In order to account for the mixing of Hamilton species with Oriskanian ‘it is necessary to imagine the Oriskanian species living through the Onondagaian epoch. Evidence of the Onondagaian fauna is known in the Chaudiére River beds, but containing no trace of the dominant Oriskanian species supposed to have lived over except Leptocelia flabellites, which is also known in the Onondaga formation of the interior, and no Hamiltonian fauna in the country has any mixture of Oris- kanian species. The Chaudiére beds are midway between the Gaspé and Saint Helens beds. How will we account for the continuance of the Oriskany species till Hamiltonian epoch without showing some trace of themselves in the inter- val or in the typical basin of Hamilton sediments, with which open connection with the Gaspé locality has been assumed? Not only are the underlying Grande Gréve limestones filled with a domi- nantly Oriskanian fauna, but the Nictaux beds, Nova Scotia, the Campbell River beds in New Brunswick, the Chapman sandstone in Aroostook county, the Moose River sandstone in Somerset county, Maine, and the Upper Saint Helens and Coté Saint Paul, near Montreal (thus quite surrounding the Gaspé peninsula), are all filled with a very closely allied fauna to that deseribed from the York River beds at the base of the Gaspé sandstone. This gives strong ground for belief that there were open connected seas in which the fauna lived. But inside the Connecticut-Saint Lawrence trough not the least trace of the Onondagaian fauna is in evidence, and no hiatus or unconformity in the Gaspé section furnishes reason for supposing that the Gaspé series from the limestones upward through the sandstones was not a continuous deposition. The combination of species in the York River beds at Gaspé, as well as in the Upper Saint Helens beds and at Coté Saint Paul, near Montreal, is re- markable in containing elements of two faunas mixed which we are accus- tomed to find dissociated. The dissociation of the separate faunas is, however, not due to the entirely different time of existence of the two faunas, but to the fact that the two faunas for long periods of geologic time have occupied sepa- rate areas of space on the globe. We can not maintain the idea that during the Oriskanian epoch the genera, and.certainly very closely allied species of the genera, which were characteristic of the Hamiltonian fauna did not actually live somewhere and in a flourishing condition and in abundance during the Oriskanian epoch. But they lived in a different sea basin from that in which the characteristic Oriskanian fauna flourished. It is the running to- gether of elements of the two faunas that is anomalous. It is possible to imagine that the dominant species of the Oriskany suddenly became extinct, but not that the dominant species of the Hamilton suddenly came into exist- ence without ancestors. It is with this point of view that in such a mixed fauna we are forced to use the dominant species in determining the age of the fauna, and to regard the rare and occasional species as indication of the race whose time relations may date back to early Paleozoic time, if not earlier, and forward even to the present time. | a AGE OF THE GASPE SANDSTONE 698 SUMMARY OF EVIDENCE To sum up the evidence, the facts briefly stated are as follows: In the York River beds at the base of the Gaspé sandstones there is found a number (at least a dozen) of fossils which if found alone would be inter- preted as positive evidence of an Oriskanian fauna; associated with these is another lot of fossils, at least as many, which if found alone would be as positive evidence of a Hamiltonian fauna. The sediments were deposited at some particular epoch of the geological time scale. What does this composite fauna Signify as to the epoch to which the York River beds belong? Doctor Clarke in the volume referred to gives the decision in favor of the Hamiltonian epoch, apparently on the ground of the greater number of species identical or closely related to Hamiltonian forms. If we accept his view it follows that the associated Oriskanian forms continued to live on after the epoch of the Oriskanian fauna into Hamiltonian time. By the interpretation here offered it is assumed that the Hamiltonian types of the fauna are possible ancestors of Hamilton species living in the Oris- kanian epoch, which by some movements of the currents of the ocean were brought together in the Acadian province before the revolution which upset the biologic equilibrium of the Oriskanian fauna had completed its work. The further conclusion is that it was the same events which caused the cessation of the distinctive Oriskanian fauna, which brought into this area the ancestors of the Hamilton species, and that the geologic time of the events was approximately equivalent to the Schoharie epoch of New York state. The following specific facts seem to corroborate this interpretation: 1. Lower Devonian faunas of the Rhine and Hartz regions of Europe con- tain a similar combination of species; Rensselerias, Eatonia-like Rhynchonel- lids, large coarse-ribbed Spirifers, associated with Tropidoleptus, Grammysia hamiltonensis, Cyrtini heteroclita, etcetera, to mention but a few striking cases. 2. Tropidoleptus, a prominent representative of the fauna, is already traced downward as far as the typical Oriskany in the Maryland Oriskany. 3. The Nictaux fauna of Nova Scotia and the Moose River sandstone fauna of central and northern Maine, in both of which there is also found Spirifer arenosus, Show similar admixture of species having close affinity with the Hamiltonian fauna. 4. The upper mass of the breccias of Saint Helens, which contains the Coté Saint Paul species, also has undoubted example of Spirifer arenosus. 5. The Nictaux, Moose River, and Upper Saint Helens beds contain domi- nant Oriskany species as the dominant constituents of their faunas, which taken alone would, I believe, lead any paleontologist acquainted with the faunas to assign them to the Oriskany epoch. 6. The Oriskanian fauna, although intimately associated biologically with the Helderbergian, is in North America biologically quite distinct from the Hamiltonian fauna which is an evolutional expansion of the Onondagaian, and in its dominant elements ceased with the opening of the Onondagaian epoch. 7. The evidence seems convincing that the origin of the Onondaga-Hamil- tonian fauna is from a source south of the “Indiana basin” (of Ulrich and 694 PROCEEDINGS OF THE BALTIMORE MEETING Schuchert), through which it migrated northeastward into the New York area, having at the time the elevated Appalachian land area lying east of it. 8. So far as North America is concerned the Helderberg-Oriskanian fauna appears to have had its origin from the North Atlantic, outside the Appa- lachian land. 9. To explain the Hercynian-Coblenzian combination in Europe, there ap- pears to have been a mingling of these two general faunas (the Helderberg- Oriskanian and the Onondaga-Hamiltonian), which were more or less distinet on the North American continent. 10. To explain these last three facts seems to require a North Atlantie center of distribution for the Helderberg-Oriskanian fauna, and a South Atlantic or equatorial center of distribution for the Onondagaian fauna. 11. The passage from the Grande Gréve limestone into the sandstone and conglomerates of the Gaspé sandstone series indicates an upward movement of that edge of the continent beginning during the life of the Oriskanian fauna, and its remaining above sealevel over the eastern province. 12. The distribution of the Oriskany deposits over New York state indicates a rising of sea bottom into land before the close of Oriskany, or during the time in which the closing Oriskany, the Esopus, and Schoharie grits were being deposited. 13. The coral reefs of the early Onondaga show a depression over New York state and along the Connecticut-Saint Lawrence trough, extending as far east as lake Memphremagog and Chaudiére, Quebec, in early Onondagaian time, not, however, depressing the interior province below sealevel, and the trough probably did not reach the North Atlantic basin to the eastward. 14. Although there are indications of the mixed fauna both sides of this trough (to the south in northern Maine and at Gaspé and to the north of it at Saint Helens, Montreal), the faunas of both of these limestones as reported appear to be pure Onondagaian, like the corresponding fauna seen in the more western outcrops with which they are supposed to have been connected. 15. The southern extension of the Onondagaian, in Illinois, Indiana, Ken- tucky, appears to show closer admixture with types of Helderberg-Oriskanian type than does its northern extension in the New York basin. CONCLUSIONS These arguments seem to support the hypothesis that the York River beds at Gaspé contain a marine fauna of Oriskanian type not younger in age than the Schoharie grit of New York state. On this hypothesis marine communica- tion with the Atlantic basin must have been cut off with the cessation of that fauna; the upper fauna of Saint Helens and Coté Saint Paul was of not later age than the York River beds at Gaspé; the Onondaga faunas of Owls head and Chaudiére entered from the west, having migrated around from the south- west through the Indiana basin, and the Connecticut-Saint Lawrence trough did not open out into the Atlantic basin in Onondagaian time. The explanation of the mingling of Hamiltonian types with the Oriskanian fauna in this eastern province is found in the meeting of the North Atlantic fauna of Oriskanian type with the South Atlantic fauna of Hamiltonian type, coincident with the rising of the land which caused the continental border of the continent to transgress eastward. panes AGE OF THE GASPE FORMATION 695 Later the southern fauna found a way into New York through the Indiana basin, but with only such slight admixture of species of the northern fauna as could migrate southward in the Atlantic basin and enter through the Gulf basin into the interior continental basin. The fundamental correlation principle involved in reaching the above con- clusions is that the time relations of a fauna are indicated by its dominant species. At any particular epoch the ancestors of all species which are to become dominant in later ages were living, and in taking samples of a fauna many forms closely related to later species may appear. The dominant ele- ments of the fauna, however, express successful adjustment of the species to the particular environmental conditions, both biological and physical, which mark the epoch of such dominance. To use a familiar figure, the paleontological record is like a carpet, and the particular species by which we recognize geological epochs are comparable to the threads brought to the surface to make the local pattern. The individual threads are long, however, and if we recognize them before or after the forma- tion in which they form the dominant pattern it is a ease of recurrence of the fauna out of its typical time horizon. It is the particular combination of domi- nant threads which makes up the pattern of each epoch as we know it, and by which the epoch is to be recognized and correlated. Diastrophism undoubtedly is a fundamental cause in determining the par- ticular pattern of the carpet at each stage in geological history. DISCUSSION REMARKS BY CHARLES SCHUCHERT Doctor Clarke and I together visited the Gaspé section, the only complete one of the Lower Devonian in all eastern America. These formations rest on the upturned black slates of the Ordovician, having about 2,000 feet of lime- stones and 7,000 feet of sandstones. The section apparently begins with basal New Scotland time, for here we collected Gypidula galeata and Leptenisca concava, and then the section continues unbroken into the Middle Devonian. Above these Helderbergian limestones fossils are scarce until near the Grande Gréve horizon. In going along the bed of a small stream we were greatly sur- prised to come upon large surfaces of a crystalline heavy bedded limestone, on which lay Rhipidomella musculosa, Hipparionyx proximus, and Rensseleria ovoides, the three most typical late Oriskanian fossils. On my next visit I located this horizon very exactly, and it is at the base of or even below the Grande Gréve zone. Collecting in this limestone reminds one strongly of the true Oriskany of Albany county, New York. The Grande Gréve limestone fol- lows, and has many Oriskanian species—in fact, the fauna 1s more decidedly of this time than of the Onondaga, and yet there are reminders of this Middle Devonian time. These limestones are followed by about 1,000 feet of sand- stone in which no fossils occur, and then appears the York River fauna. While collecting these fossils one is impressed with their Hamilton aspect, and one would make this correlation positive were it not for the presence of Renssele- ria ovoides gaspensis, Hatonia peculiaris, Leptocelia flabellites, Chonostrophia dawsoni, and Phacops correlator. Then all marine faunas cease, and the re- mainder of the sandstone is probably of continental character. 696 PROCEEDINGS OF THE BALTIMORE MEETING It is clear, however, that the true Hamilton fauna is not present in the York River beds, because most of the diagnostic brachiopods are absent, even T'ropi- doleptus carinatus. From the character of the Hamilton faunas of -Maryland, as described by Professor Swartz, I conclude that they came into this region from the east, and if this is so, then all the more should the typical Hamilton fauna be in the York River beds, if the horizon is of Hamilton time; but it is not there. That this Hamilton fauna was in existence elsewhere long before it appeared in the United States is seen in the western European Coblenzian faunas, and any one must be so impressed on looking at the photograph of a fine Upper Coblenzian slab figured in Frech’s Lethzea Geognostica, plate 240. The problem before us is certainly a difficult one. 1. I think Professor Williams takes too broad a view of the Saint Belen fauna. The Hamilton-like fossils are in the agglomerates, and are not asso- ciated with the limestone below the agglomerate that seemingly are in place. Those that I collected are rather of Onondaga time than of Hamilton. 2. I do not believe in Professor Williams’s principles referred to on page —. We can not in most cases rely on the common dominant species as the true guides for time indicators. It is rather the rarer species. It is this principle of Professor Williams that so many of us object to and which we believe obscures the true chronological significance of the fossils. 3. I do not hold with Doctor Clarke that the Pelecypoda of the Gaege sand- stone (York River zone of Williams) are of decided value in indicating Hamil- ton time. They may just as well be of Coblenzian time (= Oriskany). 4. The list cited by Williams is certainly striking as of late Lower Devonian time, and more value should, it seems to me, be placed on these than the other fossils of Hamilton aspect. As the true Oriskany assemblage, however, lies so far beneath—in fact, be- veath the Grande Gréve limestone—is what leads. me to conclude that the York River horizon holds a time above the New York Oriskany. According to my observation, I am disposed to place this horizon definitely in the Onondaga. If Professor Williams thinks it should go near the base of this horizon (= Schoharie) I will not object, nor will I object if Doctor Clarke places the time late in Onondaga, but I would not like to correlate the fauna with the Marcellus. 5. My paleogeographic maps are in harmony with the views here expressed. 6. The true Oriskany is North Atlantic. The Camden chert of Tennessee and Illinois has some of this Hamilton fauna. This is in agreement with faunas of Meecuro and Ereré. The home of this fauna is South American and the southern Atlantic, and it occurs there as early as Oriskanian time. 7. The Helderberg fauna is of the medial Atlantic. It comes in from the Gulf, and probably also by way of New Jersey. In the Acadian region the faunas are different, with only a few of the medial or southern Atlantic species. Further, this element is unknown in northern Europe, but is widely known in the Mediterranean extensions. REMARKS BY JOHN M. CLARKE The point of view taken by Professor Williams impresses me as a very nat- ural one in view of the presence in the Gaspé sandstone fauna of certain lead- ing Lower Devonic species, and this view was indeed that entertained by myself i: ae 7 OC la 62" 2 © 2) Oo ee ne er 4, «<% A ieee? 2 < ok AGE OF THE GASPE FORMATION 697 until an intimate acquaintance with the fauna convinced me of what has seemed to me a more trustworthy expression of its relationships. The Hamil- ton element in this composition is not, I should say, ancestral or merely pre- nuncial. We have a striking array of species identical in structure with the Hamilton species of New York. I confess the conception “dominant species,” on which the speaker lays much weight, is not to me very imperative. I should say that in this case the dominant species are not so much the survivors from the previous fauna as the Hamiltonian assemblage therein, as the latter is dominant, both in respect to actual individual membership and in percentage of the species as a whole. Some of these sandstone species which had been named by Billings—as, for example, Strophomena blainvilli and Spirifer gaspensis— may yet prove to be actually identical with Hamilton species, and these, to- gether with certain pelecypods, are dominant rather than the survivors. In the study of these eastern American faunas and those of the South American Devonie I have been alive to the disvaluation in time of certain migrants from earlier faunas, especially Tropidoleptus and Vitulina, and it must be nearly twenty years since I laid some stress on the fact that Tropidoleptus had lost its time value in traveling half way around the world. We must not decline to recognize the Hamiltonian assemblage in the Gaspé sandstone merely because this element of the fauna may not be composed of the commoner species which experience usually associates with typical Hamil- ton sections. The crux here is not, “What were the old surviving species doing while the Hamilton species were on their way to this region?” (from the south- west, as I conceive) but, as the speaker has stated, “Are the latter really Ham- iltonian?’ As I have described at some length their points of identity with typical Hamilton fossils, I think we must concede that they are, not ancestrally but actually, Hamiltonian, until each identification has been deliberately con- troverted. Granted that the species are competent, the age of the fauna must be interpreted in accordance with the latest age represented by its members. This is the recognized correct procedure. It is gratifying that the speaker is in agreement with the conclusion I have drawn, that the northeast basin is an area of dispersion of the Helderberg and Oriskany faunas southwestward. In defining the Grande Gréve formation it was pointed out that its lowest limestone beds carried true Oriskany types, great Hipparionyx, Rensseleria, large Leptostrophias, etcetera, and it has also been shown that these species continue upward in the formation, even to its highest beds, all the time becoming more involved in a prevailing Helderber- gian fauna, and with only a few foreshadowings or traces of the Onondaga fauna. Wherever the last element came from, whether on its way out through the Memphremagog passage or on its way in, its representatives are always very primitive in expression. There is danger before us in this field in attempting to establish a precise correlation in the eastern region with the faunas of the Appalachian basin of Devonie time. In view of the distances involved and the still obscure paleo- geographic conditions, such ventures should be cautious and restrained. Ap- proximately equivalent expressions are all that can be expected. REMARKS BY H. S. WILLIAMS In reply to the comments made by Professor Schuchert: 1. I am well aware of the difference between the agglomerates (252.1) and 698 PROCEEDINGS OF THE BALTIMORE MEETING the limestone mass (252.2) of the Saint Helens breccias. The two faunas are quite distinct; that of the limestone is pure Helderbergian; the other, which I have called the Upper Saint Helens (252.1), contains a distinct fauna. It is this Upper Saint Helens which I identify as Oriskanian because of the pres- ence of Spirifer arenosus and Hatonia. In it occur the species having the strongly Hamiltonian aspect. 2. Regarding the importance of dominant species in determining correlation, I regret that Professor Schuchert can not at present accept the principle. I can only add here that the rare species of a fauna do certainly testify as to its probable connection with another fauna in which the same species are dominant; but a fauna at large is characterized by its dominant species, and until evidence is furnished as to the time range to which its dominant species are restricted the time relations of the fauna are not established. 3. I quite agree with Professor Schuchert’s view regarding the Coblenzian significance of the Pelecypods of the York River beds. In my paper I was par- ticularly discussing the correlation with the immediate North American sec- tions. 4. My conclusion that the fauna should be placed at not higher than the age of the Schoharie of New York is determined chiefly by the absence of charac- teristic Onondagaian species, which have actual representatives in the neigh- boring Chaudiére limestone. 5. I had not seen Professor Schuchert’s paleogeographiec charts when the paper was written, and am gratified to know that we are in harmony in inter- preting the geography of this time. 6 and 7. Professor Schuchert’s differentiation a origin between the Helder- bergian and Oriskanian faunas is quite consistent with my view. In my inter- pretation I had classed the Helderbergian with the Oriskanian faunas, distin- guishing them from the Onondagaian-Hamiltonian faunas. I am quite ready to grant that the Helderbergian had its center of distribu- tion farther south than the Oriskanian, but in my grouping them together I referred to the North Atlantic, north of the equator. If we adopt Professor Schuchert’s location of the Helderbergian in a separate center of distribution farther south than the Oriskanian, I think we have good reason for the early appearance of the Oriskanian fauna at the base of the Grande Gréve limestone. In reply to Doctor Clarke’s remarks, if we ask the question, “Are the species so called really Helderbergian?’ we get only an evasive answer. Doctor Clarke’s claim was that the fauna of the York River beds was equiva- lent in time to the epoch of the Hamilton formation of New York. I do not deny that the species from the York River beds given names of Hamilton species actually possess the specific character of those species. My contention is that the paleontologic evidence before us indicates that these “Hamiltonian” species of the York River beds lived and were buried in association with Oriskanian species on the Gaspé peninsula at a time corre- sponding with the Coblenzian of Europe, and probably not later than the Schoharie beds of New York. The section adjourned at 12.30 Pp. M. and met again at 2.15 P,. M. with Professor W. B. Clark in the chair. BRACHIOPODA OF THE RICHMOND GROUP 699 The following two papers were read by title: THE AFTONIAN SANDS AND GRAVELS IN WESTERN IOWA BY BOHUMIL SHIMEK AN AFTONIAN MAMMALIAN FAUNA BY SAMUEL CALVIN Then was presented orally BRACHIOPODA OF THE RICHMOND GROUP BY AUGUST F. FOERSTE [Abstract] In the area dominated by the Cincinnati geanticline there have been several invasions of the brachiopoda considered most typical of the Richmond group. The first of these occurred near the middle of the deposition of the Arnheim bed. The Richmond group of the Mississippi valley, as far as may be deter- mined from a study of the brachiopoda. finds nearer representatives in the upper or Blanchester division of the Waynesville bed and in the Liberty bed than in the Arnheim, Lower Waynesville, or Whitewater beds. A study of the distribution of the brachiopoda in Ohio, Indiana, and Kentucky suggests that the centers of distribution lay more frequently toward the northeast than toward the northwest or west of the present areas of exposure. To account for this, it is imagined that the Richmond group of the Ohio valley was connected with that of the Mississippi valley by way of northern Indiana and Illinois. Possibly, if the areas now covered by overlying formations could be exposed, the Richmond brachiopoda would be found to be absent in southern Indiana and Illinois and in western Kentucky, west of the present areas of exposure of these fossils in the region of the Cincinnati geanticline. Lithological conditions within the areas dominated by this geanticline favor this view. K. R. Cumings discussed this paper. After this the following paper was read: TRAP SHEETS OF THE LAKE NIPIGON BASIN BY ALFRED W. G. WILSON This paper has been published as pages 197-222 of this volume. This paper was discussed by A. W. Grabau, A. W. G. Wilson, A. C. Lane, and A. F. Foerste. 700 PROCEEDINGS OF THE BALTIMORE MEETING Then was read RECONNAISSANCE IN ARIZONA AND WESTERN NEW MEXICO ALONG THE SANTA FE RAILROAD BY N. H. DARTON [Abstract] The reconnaissance was made for the purpose of ascertaining the prospects for deep wells to supply water to the railroad and settlements along its line. . The region examined was from ten to forty miles wide, and in this area the principal structural and stratigraphic features of formations from Cambrian to Cretaceous were determined. This was followed by the reading of GEOLOGIC STUDIES IN THE ALASKA PENINSULA BY WALLACE w. ATWOOD! [Abstract] Detailed work was done in the vicinity of Chignik, Balboa, and Herendeen bays and on the island of Unga. The Balboa-Herendeen Bay district was selected as a type area in the peninsula, and detailed studies were pursued in the hope of working out a key to the general geologic conditions of this portion of Alaska. The formations exposed include the Upper Jurassic, Lower and Upper Cre- taceous, marine and fresh-water Eocene, Miocene, possibly some Pliocene and Pleistocene, and recent Kenai plants were found associated with marine in- vertebrate shells of Upper Eocene age. Vast quantities of igneous rocks have been intruded into the sedimentary series, and overlying a portion of the area there are volcanic tuffs and basic” flows of post-Miocene age. Coal occurs in the Upper Cretaceous and Eocene. Gold and copper prospects were examined at several localities. Then was presented orally PRESENT KNOWLEDGE OF THE OKLAHOMA RED BEDS BY CHARLES N. GOULD After this the following paper was read: FAUNA OF THE FERN GLEN FORMATION BY STUART WELLER The paper was discussed by Charles Schuchert, Stuart Weller, and EK. O. Ulrich. 1 Introduced by A. H. Brooks. ates. *. TITLES OF PAPERS 701 The next two papers were read by title: AGE AND GEOLOGIC RELATIONS OF THE SANKATY BEDS, NANTUCKET BY W. O. CROSBY AGE AND RELATIONS OF THE SANKATY BEDS BY H. W. SHIMER' Then the following paper was read: SOME FEATURES OF THE WISCONSIN MIDDLE DEVONIOC BY H. F. CLELAND [Abstract] This paper gave the results of a study of all the outcrops, as far as known, of the Wisconsin Devonic and their contained faunas. In it were discussed: (1) the relation of the strata to those above and below, (2) the unconformities, (3) the lithological characters, and (4) the character, relationships, and geo- graphical distribution of the faunas. Charles Schuchert, A. W. Grabau, and H. M. Ami participated in the discussion of this paper. The next paper read was ICE-BORNE BOULDER DEPOSITS IN MID-CARBONIFEROUS MARINE SHELLS BY JOSEPH A. TAFF [Abstract] Great numbers of boulders and other erratic fragmental rock debris occur in the Caney formation of the Ouachita Mountain region in southeastern Okla- homa. The erratic material consists of boulders, cobbles, and small rock frag- ments of three general classes, namely: (1) limestones—siliceous, argillaceous, and magnesian; (2) flints, cherts, and (3) quartzites. The limestones are of various textures and colors, some of which partake of the nature of the quartzites, while others are argillaceous; others yet appear to be dolomitic or perhaps dolomites. Many of the limestone boulders are massive and homogeneous, while others are distinctly stratified and contain two or more classes of limestone or strata of limestone and flint. Flint and chert boulders are also of common occurrence, and in places are even more abundant than the limestone boulders. Certain of these flints are stratified or bedded and are black or bluish in color, while others are massive, chalcedonic in character, and contain inclusions of drusy quartz. Among these are many of conglomeratic and brecciated nature. 1 Introduced by W. O. Crosby. = a TZ PROCEEDINGS OF THE BALTIMORE MEETING The third group in the general classification of these erratics includes quartz- ites of dark and reddish hues. These erratic boulders vary in size from small pebbles to boulders of enor- mous size, a few of which attain lengths of more than 50 feet. Many of the smaller boulders are more or less rounded, while a few are quite perfectly so. The larger ones are, as a rule, angular. At three separate localities in the Ouachita Mountain region certain of the limestone and flint boulders contain grooves and strize as if produced by the action of shore ice. Certain of these strize also resemble the markings of slickensided surfaces. The evidence as to the origin of these gouged surfaces is not conclusive. The erratic boulders contain a comparatively abundant Ordovician and Silu- rian fauna. The boulders are promiscuously scattered in the Caney formation of black and blue shale with local beds of sandstone in the upper part. The Caney formation is several hundred feet thick and contains limy concre- tions or segregations, associated with the erratic boulders and elsewhere, that contain an abundant fauna of late Mississippian or early Pennsylvanian age. The area of boulder-bearing beds of the Caney formation, as now known, is within the Ouachita Mountain uplift in Oklahoma that extends within a few miles of the Arkansas line to the west end near Atoka. The structure of the region is typically Appalachian, the rocks being closely folded and thrust north- ward. On comparison, both lithologically and faunally, the erratic boulders are found to contain identical characteristics in the Cambro-Ordovician and Silu- rian rocks in the Ouachita Mountain region of Oklahoma and in the Cambro- Ordovician section in north-central Texas. There are evidences of emergence of the rocks of mid-Carboniferous time in the western part of the Arbuckle uplift and in the Texas region to the southwest that affect the Cambro-Ordo- vician and Silurian rocks. The tentative conclusion is that the boulders were transported from a land to the south by the agencies of ice. This paper was discussed by David White, W. C. Alden, and J. A. Taff. The last paper on the sectional programme read was RELATIONSHIPS OF THE PENNSYLVANIAN AND PERMIAN FAUNAS OF KANSAS AND THEIR CORRELATION WITH SIMILAR FAUNAS OF THE URALS BY J. W. BEEDE [Abstract] Owing to physical changes which occurred during the close of Pennsylvanian time, there occurred a great reduction of Pennsylvanian species, followed by the introduction of Permian species. This introduction of new species becomes very noticeable in the Elmdale formation, and its base is considered the base of the Kansas Permian. The Permian, as here understood, includes the Artinskian and “Permo-Carboniferous” of Eurasia. ld {ITLES OF PAPERS 203) NINETEENTH ANNUAL REPORT OF THE COMMITTEE ON PHOTOGRAPHS The Photograph Committee, Mr N. H. Darton, reported that there had been few accessions during the year and practically no use of the collec- tion. TITLES OF PAPERS PRESENTED BEFORE SECTION £ OF THE AMERICAN : ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE On account of the length of the programme, the Council formed a special section for the consideration of certain papers forming part of a_ symposium on correlation which had been arranged for by Bailey Willis, chairman, and F’. P. Gulliver, secretary, of Section E (geology and geog- raphy) of the American Association for the Advancement of Science. For the sake of record the whole list of these papers, with the times when they were read, follows. MONDAY, DECEMBER 28 Pre-Cambrian 11.00 a. mM. to 12.10 P. M. C. R. Van Hise: “Principles of Pre-Cambrian correlation.” F. D. Adams: “The basis of Pre-Cambrian correlation.” Early and Middle Paleozoic 3.30 to 4.00 P. M. C. D. Walcott: “Evolution of early Paleozoic faunas in relation to their en- vironment.” 4.00 to 5.50 P. M. A. W. Grabau: “Physical and faunal evolution of North America in the late Ordovicie, Siluric, and Devonic time.” 4.50 to 5.30 P. M. Stuart Weller: “Correlation of Middle and Upper Devonian and Mississip- pian faunas of North America. TUESDAY, DECEMBER 29 Late Paleozoic 11.00 a. M. to 12.05 P. M. G. H. Girty: “Physical and Faunal changes of Pennsylvanian and Permian in North America.” David White: “The Upper Paleozoic floras, their succession and range.” LXV—BULL. GEOL. Soc. AM., VoL. 20, 1908 704 PROCEEDINGS OF THE BALTIMORE MEETING Vertebrates 2.00 to 3.15 P. M. S. W. Williston: “Environmental relations of the early vertebrates.” H. F. Osborn: “Environment and relations of the Cenozoic mammalia.” Mesozoic and Tertiary 3.15 to 4.00 P. M. T. W. Stanton: ‘‘Suceession and distribution of later Mesozoic invertebrate faunas.” 4.00 to 5.15 P. M. W. H. Dall: “Conditions governing the evolution and distribution of Tertiary faunas.” Ralph Arnold: “Environment of the Tertiary faunas of the Pacific coast.” WEDNESDAY, DECEMBER 30 Tertiary and Quaternary 10.50 to 11.25 a. M. I’. H. Knowlton: “Succession and range of Mesozoie and Tertiary floras.” 125A ME tO 1225 Ps Me Rh. D. Salisbury: “Physical geography of the Pleistocene with special refer- ence to conditions bearing on correlation.” D. T. MacDougal: “Origination of self-generating matter and the influence of aridity on its evolutionary development.” 2.30 to 3.45 Pp. M. VT. C. Chamberlin: “Diastrophism as the ultimate basis of correlation.” After the reading of scientific papers had been finished the Society met again in general session, and Dr J. M. Clarke proposed a vote of thanks to the citizens of Baltimore, the authorities of the Johns Hopkins Uni- versity, and in particular to the members of the department of geology, for the welcome accorded to the Society and the particularly complete arrangements made for the work of the meeting and the comfort and enjoyment of those in attendance. The vote was most heartily passed, and was responded to by Professor W. B. Clark in behalf of the Balti- moreans concerned. REGISTER OF THE BALTIMORE MEETING 705 REGISTER OF THE BALTIMORE MEETING, 1908 ADAMS, FRANK Dawson Ami, Henry M. ARNOLD, RALPH ASHLEY, GEORGE HALL Bain, Harry Foster Bace, Rurus MATHER, JR. BARRELL, JOSEPH Bascom, FLORENCE BassuerR, Ray SMITH BAYLEY, WILLIAM 8. BEcKER, GEORGE F. BEEDE, JoSHUA W. BERKEY, CHARLES P. BEYER, SAMUEL WALKER BIBBINS, ARTHUR B. BriGHAM, ALBERT PERRY Brock, REGINALD W. CALVIN, SAMUEL CAMPBELL, HENRY DONALD CAMPBELL, Marius R. Case, ERMINE C. CHAMBERLIN, T. C. CuaRK, WILLIAM BULLOCK CLARKE, JOHN MASON CLELAND, HEerpMAN F. CLEMENTS, J. MorGan CoLEMAN, ARTHUR P. CoLLieR, ARTHUR J. CrosBy, WILLIAM O. Cross, WHITMAN Cumines, Epaar R. CusHING, Henry P. Darton, NEtson H. DILLER, JOSEPH S8. Dover, RicHArD KH. Emerson, BENJAMIN K. The following Fellows were in attendance at the meeting: EunMons, SAMUEL F. FAIRCHILD, HERMAN L. FENNEMAN, NEvIN M. Forrste, Aucust F. GILBERT, GRovE K. Gorpon, CHaruEs H. GOULD, CHARLES NEWTON GRABAU, AMADEUS W. GREGORY, HERBERT E. GULLIVER, FREDERICK P. Haguk, ARNOLD HARRIS, GILBERT D. Hayes, C. WILLARD Hopss, WILLIAM HERBERT HOoLuick, ARTHUR Hovey, EDMUND OTIS Howse, ERNEST HOWELL, EDwIn E. HuBssBarpD, Lucius L. Huntineron, ELLSwortH IpDINGS, JosEPH P. JEFFERSON, Marx 8S. W. JOHNSON, DoucLas WILSON ‘KEITH, ARTHUR KEYES, CHARLES ROLLIN KNOWLTON, FRANK H. Kraus, Epwarp HENRY KtUMMEL, Henry B. LANE, ALFRED C. Lez, WitLtis THomas LEVERETT, FRANK LEwIs, JOSEPH VOLNEY LINDGREN, WALDEMAR Low, ALBERT P. Martin, GEORGE CurRTIS MatHews, EDWARD B. 706 MatrHew, W. D. MENDENHALL, WARREN C. MILLER, ARTHUR M. MILLER, BENJAMIN IL. MILLER, WILLET G. OGILVIE, IpDA HELEN Osporn, Henry F. Parks, WILLIAM A. Patton, Horace B. PERKINS, GEORGE H. PRATT, JOSEPH HYDE PROSSER, CHARLES S. PurDUE, ALBERT HOMER Rep, Harry FIELDING Rick, WiLLiaM NortH RICHARDSON, CHARLES H. Rises, HEINRICH SALISBURY, ROLLIN D. SCHRADER, FRANK C. SCHUCHERT, CHARLES SMITH, GEORGE OTIS SPENCER, J. W. PROCEEDINGS OF THE BALTIMORE MEETING Tarr, JOSEPH A. TaRR, RaLpH 8. TAYLOR, FRANK B. ULRICH, Epwarp O. Van HiszE, CHARLES R. Van Horn, FRANK ROBERTSON VAUGHN, THOMAS WAYLAND WaLcort, CHARLES D. Waker, THomas L. WARREN, CHARLES H. Watson, THomas L. WEIDMAN, SAMUEL WELLER, STUART WESTGATE, LEWIS G. WHITE, DAvIpD WHITE, ISRAEL C. WILLIAMS, HENRY S. WILLIS, BAILEY WILLISTON, SAMUEL W. WILSON, ALFRED W. G. WOLFF, JOHN HE. WoopwarD, RoBeErt S. WRIGHT, FREDERICK H. WricuHt, G. FREDERICK STANTON, TIMOTHY WILLIAM STEVENSON, JOHN J. And the following Fellows-elect : Brown, CHARLES WILSON Kay, GEORGE FREDERICK CARNEY, FRANK RICHARDSON, GEORGE BURR FisHER, Cassius ASA STOSE, GEORGE WILLIS JOHANNSEN, ALBERT SwaRtTzZ, CHARLES KEPHART CORDILLERAN SECTION 707 SESSIONS OF THE CORDILLERAN SECTION, AT STANFORD UNIVERITY, CALI- FORNIA, WEDNESDAY AND THURSDAY, DECEMBER 30 AND 31, 1908 TITLES OF PAPERS PRESENTED BEFORE THE CORDILLERAN SECTION SOME FOSSIL FISHES FROM BRAZIL BY DAVID STARR JORDAN" PYRITE MINES OF LEONA HEIGHTS BY JOSIAH KEEP?! AN OLD BEACH TERRACE IN NEVADA BY J. CULVER HARTZELL' GEOLOGY OF THE SILVER PEAK QUADRANGLE, NEVADA BY H. W. TURNER! A REMARKABLE CLAY BY J. CULVER HARTZELL' EXPERIMENTS WITH A SHAKING MACHINE MADE WITH A VIEW TO DETER- MINING THE EFFECT OF WATER UPON LOOSE MATERIAL BY F. J. ROGERS! COMPARISON OF THE EFFECTS OF THE HARTHQUAKES OF MENDOZO, ARGEN- TINH REPUBLIC, VALPARAISO, JAMAICA, AND SAN FRANCISCO BY J. C. BRANNER GEOLOGY OF SOUTHERN JAPAN BY ROBERT ANDERSON?’ PHAT DEPOSITS OF THE LOWER SACRAMENTO AND SAN JOAQUIN RIVERS BY W. Q. WRIGHT! MINERALS FROM THE COAST RANGES OF CALIFORNIA BY A. F. ROGERS’ 1Introduced by J. C. Branner. 708 PROCEEDINGS OF THE BALTIMORE MEETING DETERMINATION OF MINERALS IN CRUSHED FRAGMENTS BY MEANS OF THE POLARIZING MICROSCOPE BY A. F. ROGERS! SYNOPSIS OF THH STRATIGRAPHY OF OALIFORNIA BY JAMES PERRIN SMITH?! STRUCTURE OF THE CENTRAL PORTION OF THE COAST RANGES OF OALIFORNIA BY J. F. NEWSOM SEDIMENTARY FORMATIONS OF THE COALINGA DISTRICT, CALIFORNIA BY ROBERT ANDERSON?! NHOCENE OF THE UPPER SALINAS VALLEY REGION BY ROBERT MORAN? RESUME OF THE GEOLOGY OF BRAZIL BY ORVILLE A. DERBY GHOLOGY OF THE REGION OF DIAMONDS AND CARBONADOS IN BRAZIL BY J. C. BRANNER RECONNAISSANCE ABOUT THE BIG SUR REGION OF THE SANTA LUCIA MOUNTAINS BY J. CULVER HARTZELL? PROPOSED FORM OF SHEISMOGRAPH INTENDED TO GIVE A DIRECT INDICATION OF THE FORCES IN PLAY* BY W. F. DURAND* [Abstract] (1) The usual forms of seismograph indicate displacement, and if this is recorded on a time axis an analysis of such record may give indications of acceleration and force. (2) The instrument suggested is intended to give a more direct indication of acceleration and force. (8) In the usual forms an oscillating system of long period (usually some form of pendulum) is provided with a tracing point, while a roll of paper is mounted on the frame-work and is unrolled under such point. When the sys- tem is subjected to a relatively short period disturbance the pendulum remains * Manuscript received by the Secretary of the Society February 27, 1909, 1 Introduced by J. C, Branner, PROPOSED FORM OF SEISMOGRAPH 709 substantially at rest, while the movement is communicated directly to the frame-work and paper, which thus moves under the tracing point. (4) The instrument suggested consists of a mass of metal resting on rollers or steel balls, and connected by a thin steel band to a sheet metal diaphragm. This diaphragm forms one boundary of a cell containing water or some other liquid, and is furnished on the opposite side with pipe connection and vertical glass tube. The cell is securely attached to a base plate, and thus to the earth, and hence must share in whatever movement may be imposed on the earth at this point. Through the connection with the diaphragm such movement will also be imposed on the mass of metal referred to (except for the slight yield of the diaphragm), and thus we have a known mass whose motion must neces- sarily be a close copy of the actual earth movement. This imposed oscillatory FiGurRE 1.—Proposed Form of Seismograph motion will develop forces due to the acceleration and retardation of the mass of metal, and these forces will give rise to minute displacements of the dia- phragm. These movements by the method indicated may be multiplied one thousand fold or more, and thus made visible as a rise and fall of the liquid in the tube. (5) Various means might be employed for registering either the maximum excursion of the liquid or of obtaining a complete registration. These are mat- ters of detail not fully worked out and not important, so far as the main prin- ciple of the apparatus is concerned. (6) The instrument may be made more or less sensitive by varying the thick- ness of the diaphragm and the diameter of the tube. With easily realized dimensions an ordinate of 3 or 4 inches may be obtained with not to exceed .002 or .003-inch movement of the diaphragm. (7) By calibration the actual forces in play corresponding to any change in level of liquid are easily determined, and such forces expressed as percentages 710 PROCEEDINGS OF THE BALTIMORE MEETING of the weight of the mass of metal would furnish a ready and rational basis for rating the intensity of an earthquake shock. (8) Such an apparatus would naturally give only a single component, such as east or west. As with other forms of seismograph, three units would be required to furnish a complete history of the value and direction of the total force. (9) The instrument here suggested may possibly by itself be made to give indications of some value regarding maximum intensities, and, taken as supple- mentary to the record of a displacement seismograph, might serve to give val- uable collateral indications regarding the various characteristics of the dis- turbance. (10) Preliminary trials with an instrument made up with a special form of diaphragm pressure-gauge indicate results of a hopeful character, and an in- strument more definitely planned for seismographic work is now under con- struction. ACCESSIONS TO THE LIBRARY FROM NOVEMBER, 1908, TO NOVEMBER, 1909 By H. P. Cusuine, Librarian Contents age (A) From societies and institutions receiving the Bulletin as donation (‘‘IEx- CUTAN OS A eRU Vener iter alste vei sire edevte relieve caveliel eral sialic vel ol cher alter svevevere ete: cue sienekei ove: euieroveleusltane ene veus 711 (Ca) Rr AtrT OTST Cay peri rcire a ei ciletis ts) ere leltol eirevte)oreuel ol clieifel elisl slieivelle) ee) oyeleierayeie ele le: e0 ec eleeieeuehagels 711: (CO) MET UROP Cheater exci ler cveveuelcheioehole) ete tacelelcielenese es ieireieie Biot eleiverloneieiciae sevaus coh ramones 713 (ON BPAS Tate aap ePeepeserenetenererexorsianezeconere love -olers Sele ueneledekavereie voetoieicwenol'cieetecsis) eareiette 717 (CePA tral asia eiczs lec cuene re cc 'sirer.6) 62.5. eileverteie! sive) 6).6: (6) s\isiiei oyster Bi eronal ore svarsueusiteitonenalsiavele T17 (CEPA TTY CAE arere cre revalralione tatters! 6: overiara euinrel(enesiel srin oavietsvetexe /sveleleirene lane eioliere-’ steleracele) eee 717 (B) From state geological surveys and mining bureaus.......ecccccesssssresseee 718 (0) From scientific societies and institutions. ......ccccccscscvvcsccessesrsssecs 718 (BN) -ANTRTENGS are ese acicanac yeh Sac Onn RCRC ECE SEE TELOROLOR). cia aR CE Cer a ECR UE Iecernca 718 QUOT ODG) cl vain's, 0. ¢ wiai's, oveic: ace eye acere Setter cua ave ci Senne coo Sietabe aster aiios 718 GMA Taira o, ar aici orratn oe 5j.0tnial widehrai 25 eileslelratior ovo rairerteice. ies Oriel Sr-sile teri aici avetral lotlveee Sezeveneletene 719 (D) From Fellows of the Geological Society of America (personal publications).... 719 (#) From miscellaneous sources .........0.- shetavavovaleraverevel cofeie ete ecctalenorsveraiecenietetenn s 720 (4) From SocrgTigs AND INSTITUTIONS RECEIVING THE BULLETIN AS DONATION (“EXCHANGES”) (a) AMERIOA NEW YORK STATE MUSEUM, ALBANY 3426-3429. Museum Reports, no. 60, parts 1-3, and 5. 3460-8461. Museum Reports, no. 61, parts 1 and 3. 3834. Bulletin 123. 3398. Bulletin 124. 3433. Bulletins 125-127. BOSTON SOCIETY OF NATURAL HISTORY, BOSTON 3244. Proceedings, vol. 34, nos. 4-7. MUSEO NACIONAL DE BUENOS AIRES, BUENOS AIRES 3374. Anales, serie 3, tomo ix. CHICAGO ACADEMY OF SCIENCES, CHICAGO 35038. Bulletin, vol. 3, no. 1. CINCINNATI SOCIETY OF NATURAL HISTORY, CINCINNATI 3548. Journal, vol. xxi, no. 1. MUSEO DE LA PLATA. LA PLATA 3440. Revista, tomo xiv. 8371. Anales, segunda serie, tomo 1, part 2. (711) 712 3443-3445. 3304. 2327. 3479. 2951. 3268. 0442. 3004. BO79. 3376. 3487. 3488. 3498. 3499. 3000. 3090. dool. 3532. 265. 3327. 3226. 3414. 3259. 3415. PROCEEDINGS OF THE BALTIMORE MEETING CUERPO DE MINAS DEL PERU, LIMA Boletin, nos. 53-54, 56-69. INSTITUTO GEOLOGICO DE MEXICO, MEXICO Parergones, tomo ii, nos. 7-10. Boletin, num. 17. Boletin, num. 26. SOCIEDAD GEOLOGICA MEXICANA, MEXICO Boletin, tomo 3-4. AMERICAN GEOGRAPHICAL SOCIETY, NEW YORK Bulletin, vol. xl, nos. 10-12. AMERICAN MUSEUM OF NATURAL HISTORY, NEW YORK Bulletin, vol. xxiv. AMERICAN INSTITUTE OF MINING ENGINEERS, NEW YORK Transactions, vol. xxxix, 1908. DEPARTMENT OF MINES, OTTAWA Geology and Mineral Resources of New Brunswick. Report on Explorations in Nova Scotia in 1907. Annual Report of the Mineral Production for 1906. Preliminary Report of the Mineral Production for 1908. Summary Report of the Geological Survey Branch for 1908. Preliminary Report on the Gowganda Mining Division. Iron-ore Deposits of Thunder Bay and Rainy River. Summary Report of the Mines Branch for 1908. Report on the Iron-ore Deposits of Nova Scotia. Mines Branch, Bulletin no. 2. Map Sheets, Nova Scotia, 39, 40, 42, 49-71, 73, 100, 101; British Columbia, Shuswap Sheet; Bancroft, Ont. ACADEMY OF NATURAL SCIENCES, PHILADELPHIA Eagene cites. vol. ix, parts 1-3, 1908. AMERICAN PHILOSOPHICAL SOCIETY, PHILADELPHIA Proceedings, vol. xlvii, nos. 188-190. MUSEO NACIONAL DE RIO DE JANEIRO, RIO DE JANEIRO CALIFORNIA ACADEMY OF SCIENCES, SAN FRANCISCO Proceedings, fourth series, vol. 3, pp. 1-48. COMISSAO GEOGRAPHICA E GEOLOGICO, SAO PAULO Boletin, 2 serie, nos. 2-4, 6. Carta Geral, Folha de Ouro Fino, Braganeca, and S, Bento. 3449, 3465-3467. 3470-3471. 3323-3324. 3017. 3364. 3536-3538. 3472-3473. 3318. 3501. 3527. doT7. 2333. 3419. 3420. 3477. 3330. 3069. 3434. 8001, ACCESSIONS TO THE LIBRARY LIBRARY OF CONGRESS, SMITHSONIAN INSTITUTION, Annual Report, 1907. UNITED STATES GEOLOGICAL SURVEY, Professional Papers 57, 58, 60. Water Supply Papers 195-206. Water Supply Papers 218-226. Twenty-ninth Annual Report. Bulletins 342-346. Bulletins 347-359. Mineral Resources, 1907, parts 1 and 2. (6) HUROPH DEUTSCHE GEOLOGISCHE GESELLSCHAFT, Zeitschrift, band Ix, heft 1-4. KONIGLICH PREUSSISCHEN GEOLOGISCHEN LANDESANSTALT UND BERGAKADEMIE, Jahrbuch, band xxvi, 1905. GEOGRAPHISCHEN GESELLSCHAFT, SCHWEIZ. GEOLOGISCHE KOMMISSION, Beitriige, lieferung 29, part 2. Beitrige, neue folge, lieferung, 21-22. Specialkarten 45, 49, 52; Erlauterungen Nr. 5-8. R. ACCADEMIA DELLE SCIENZE DELL’ INSTITUTO DI BOLOGNA, Rendiconto, nuova serie, vol. xi. Memorie, serie vi, tomo iv. NATURHIST. VEREIN DES PREUSSISCHEN RHEINLANDE, WESTFALENS UND DES REG.-BEZIRKS OSNABRUCK, Sitzungsberichte und Verhandlungen, 1908. ACADEMIE ROYALE DES SCIENCES DES LETTRES, ET DES BEAUX-ARTS DE BELGIQUE, Bulletin de la Classe des Sciences, 1908. Annuaire, 1909. SOCIETE BELGE DE GROLOGIE, DE PALEONTOLOGIE, ET D’HYDROLOGIE, Bulletin, tome xxii, fase. 1-2. Les Cristallizations des Grottes de Belgique. 713 WASHINGTON WASHINGTON WASHINGTON BERLIN BERLIN BERNE BERNE BOLOGNA BONN BRUSSELS BRUSSELS 714 3939. 3359. 3049. 3303. 3340, 3516. 32380. 3430. 3341. 3378. 3453-3454. 3174. 3511-3515. 3163. 3253. 2008. 3343. 2444, 2882. PROCEEDINGS OF THE BALTIMORE MEETING BIUROULI GEOLOGICA, MAGYARHONI FOLDTANI TARSULAT, Foldtani k6zlony, xxxviii kotet, 1-12 fuset, 1907. NORGES GEOLOGISKE UNDERSOGELSE, Report nos. 46-48. Report no. 49. DANMARKS GEOLOGISKE UNDERSOGELSE, DET KONGELIGE DANSKE VIDENSKABERNES SELSKAB, Oversigt i Aaret, Forhandlingar 1908, nr. 1-6. Shrifter, 7 Raekke, tome vi, no. 3; tome vii, no. 1. NATURWISSENSCHAFTLICHE GESELLSCHAFT ISIS, Sitzungsberichte und Abhandlungen, Jahrgang 1908. ROYAL SOCIETY OF EDINBURGH, Proceedings, vol. xxix. Transactions, xlvi, parts 1-2. NATURFORSCHENDE GESELLSCHAFT, Berichte, band xvii, parts 1-2. KGL. LEOP. CAROL. DEUTSCHEN AKADEMIE DER NATURFORSCHER, Nova Acta, band 88-89. Leopoldina, heft 43-44. COMMISSION GEOLOGIQUE DE FINLANDE, SOCIETE DE GEOGRAPHIE DE FINLANDE, Bulletins, Fennia, nos. 23-27. SCHWEIZISCHE GEOLOGISCHE GESELLSCHAFT, GEOLOGISCH REICHS-MUSEUM, K. SACHSISCHE GESELLSCHAFT DER WISSENSCHAFTEN, Berichte, Jahrgang 1908, heft 1-8. BUCHAREST BUDAPEST CHRISTIANIA COPENHAGEN COPENHAGEN DRESDEN EDINBURGH FREIBURG I. B. HALLE HELSINGFORS HELSINGFORS LAUSANNE > LEIDEN LEIPSIO Abhandlungen, math. phys. Classe, band xxx, nos. 4-5. SOCIETE GEOLOGIQUE DE BELGIQUE, Annales, tome xxviii, livr. 5. Annales, tome xxxv, livr. 1-4, 1908. Annales, tome xxx, livr. 4. Annales, tome xxxiii, livr. 4. LIEGE pn. ACCESSIONS TO THE LIBRARY 715 SOCIETE GEOLOGIQUE DU NORD, LILLE 3529. Annales, tome xxxvi, 1907. COMMISSAO DOS TRABALHOS GEOLOGICOS DE PORTUGAL, LISBON 3544. Systéme Silurique du Portugal BRITISH MUSEUM (NATURAL HISTORY), LONDON GEOLOGICAL SOCIETY, LONDON 3283. Quarterly Journal, vol. xiv, part 4. 3468. Quarterly Journal, vol. lxv, parts 1-3. 3469. The Centenary of the Geological Society of London. GEOLOGICAL SURVEY, LONDON 3328. Summary of Progress, 1908. 3439. Memoir, The Higher Crustacea of the Carboniferous Rocks of Scot- land. 3462-3463. Memoirs, Water Supply of Kent; Water Supply of Bedfordshire. GEOLOGISTS’ ASSOCIATION, LONDON 3065. Proceedings, vol. xx, part 7. 3458. Proceedings, vol. xxi, parts 1-3. COMISION DEL MAPA GEOLOGICA DE ESPANA, MADRID SOCIETA ITALIANA DI SCIENZE NATURALI, MILAN 3367. Atti, vol. xlvii, fase. 1-4, 1908. SOCIETE IMPERIALE DES NATURALISTES DE MOSCOU, MOSCOW 3399. Bulletin, Année 1907. K. BAYERISCHE AKADEMIE DER WISSENSCHAFTEN, MUNICH 3252. Sitzungsberichte, math. phys. Classe, 1907, heft 3. 3446. Sitzungsberichte, math. phys. Classe, 1908, heft 1. ANNALES DES MINES, PARIS 34382. Annales, 6e série, tome xiv, livr. 7-12, 1908. 8498. Annales, 6e série, tome xv, livr. 1-6, 1909. CARTE GEOLOGIQUE DE LA FRANCE, PARIS 2822. Bulletin, vol. xvi, no. 111. 3436-3437. Bulletin, vols. xvii, xviii, nos. 112-121. SOCIETE GEOLOGIQUE DE FRANCE, PARIS 3299. Bulletin, 4e série, tome vii, fase. 9. 3438. Bulletin, 4e série, tome viii, fase. 1-6. REALE COMITATO GEOLOGICO D'ITALIA, ROME 3331. Bolletino, vol. xxxix, nos. 1-4, 1908. 716 3372. 3450. 3368. 3346-3347. 3213. 3250. 3403-3405. 3476. 3401. 2707. 3400. 3494. 3038. 3483. 3271. 3457. 3379. 3495. 3280. 3459. 3348. 3441. 3447. PROCEEDINGS OF THE BALTIMORE MEETING SOCIETA GEOLOGICA ITALIANA, ROME . Bolletino, vol. xxvi, 1907. ACADEMIE IMPERIALE DES SCIENCES, SAINT PETERSBURG Bulletin, VIe serie, vol. ii, part 2. Bulletin, Vie serie, vol. iii, part 1. Travaux de Musée Géologique Pierre le Grand, vol. ii, livr. 1-5. Memoires, VIIIe serie, vol. xix, no. 10; vol. xx, nos. 1 and 8. Bulletin, Ve serie, tome xxv, 1906. COMITE GEOLOGIQUE DE LA RUSSIE, SAINT PETERSBURG Region aurifére de l’Amour, livr. 7. Memoirs, nouvelle serie, nos. 22, 32-35. Memoirs, nouvelle serie, nos. 28-31. Bulletin, vol. 26. Carte géologique, Region aurifére d’Jenissei, feuilles i, 8-9. Carte géologique, Region aurifére de Lena, feuilles iv, 1-2. RUSSISCH-KAISERLICHE MINERALOGISCHE GESELLSCHAFT, SAINT PETERSBURG Verhandlungen, zweite serie, band xlv. Materialen zur Geologie Russlands, band xxiii, lief. 3. GEOLOGISKA BYRAN, STOCKHOLM Sveriges Geol. Undersoékning, Arsbok 1908; series C, 209-217. GEOLOGISKA FORENINGENS, STOCKHOLM Forhandlingar, band xxx, hifte 5-7. Forhandlingar, band xxxi, hifte 1-4. NEUES JAHRBUCH FUR MINERALOGIE, STUTTGART Neues Jahrbuch, 1908, band ii. Neues Jahrbuch, 1909, band i. Centralblatt, 1908, nos. 19-24. Centralblatt, 1909, nos. 1-18. KAISERLICH-KONIGLICHE GEOLOGISCHE REICHAN- STALT, VIENNA Jahrbuch, band Iviii. KAISERLICH-KONIGLICHES NATURHISTORISCHES HOFMUSEUM, VIENNA Annalen, band xxii, nr. 1-2. GEOLOGISCHES INSTITUT DER K. K. UNIVERSITAT, VIENNA Beitrige zur Paleontologie und Geologie Osterreich-Ungarns und des Orients, band xxi. 3254. 3423. _ 2186. 3484. 2319. 3313. 3412-3413. 2527. 2445. 3281. 3520. 3547. 3046. 3464. 2138. 3497. 33801. 2713. > 8451. 3365. 3080. 3208. 3373. ACCESSIONS TO THE LIBRARY (c) ASIA GEOLOGICAL SURVEY OF INDIA, Records, vol. xxxvi, part 4. Records, vol. xxxvii. Memoirs, vol. xxxiv, part 4. Sketch of the Mineral Resources of India. IMPERIAL GEOLOGICAL SURVEY, (Ales CALCUTTA TOKYO Hitoyoshi and Wajima map sheets and text; Iki topographic sheet. BUREAU OF SCIENCE, Philippine Journal of Science, vol. iii Philippine Journal of Science, vol. i, and supplement. (d) AUSTRALASIA GEOLOGICAL DEPARTMENT OF SOUTH AUSTRALIA, Review of Mining Operations, no. 9. Reports on recent Mineral Discoveries. GEOLOGICAL SURVEY OF QUEENSLAND, Publications nos. 214-215. Publication no. 219. DEPARTMENT OF MINES OF VICTORIA, Memoirs nos. 7-8. Annual Report of the Secretary of Mines for 1907. GEOLOGICAL DEPARTMENT OF WESTERN AUSTRALIA, Bulletins 31-32. Annual Report for 1908. Annual Report for 1890. GEOLOGICAL SURVEY OF NEW SOUTH WALES, Annual Report of the Department of Mines for 1908. Records, vol. viii, no. 4. Mineral Resources, no. 6. ROYAL SOCIETY OF NEW SOUTH WALES, Journal and Proceedings, vol. xli, 1907. GEOLOGICAL SURVEY OF NEW ZEALAND, Bulletin, new series, nos. 5-6. (e) AFRICA GEOLOGICAL COMMISSION, Twelfth Annual Report, 1907. MANILA | ADELAIDE BRISBANE MELBOURNE PERTH SYDNEY SYDNEY WELLINGTON CAPE TOWN Annals of the South African Museum, vol. vii, parts 2-3. 718 3366. 3459. PROCEEDINGS OF THE BALTIMORE GEOLOGICAL SOCIETY OF SOUTH AFRICA, Transactions, vol. xi, and Proceedings. GEOLOGICAL SURVEY OF THE TRANSVAAL, Report for 1907. MEETING JOHANNESBURG PRETORIA (B) From STATE GEOLOGICAL SURVEYS AND MINING BUREAUS 3525. 3417. 3041. 3486. 3435. 3500. 2553. 2904. 3456. 3448. 3406. 3232. 3490. 3418. GEOLOGICAL SURVEY OF GEORGIA, Bulletin 19. GEOLOGICAL SURVEY OF OHIO, Bulletin, fourth series, no. 9. Geological Map of Ohio, 1909. CONNECTICUT GEOLOGICAL SURVEY, Third Biennial Report. OKLAHOMA GEOLOGICAL SURVEY, Bulletin no. 1. GEOLOGICAL SURVEY OF NEW JERSEY, Annual Report for 1908. (C) FRoM ScIENTIFIC SOCIETIES AND INSTITUTIONS (a) AMERICA BROOKLYN INSTITUTE OF ARTS AND SCIENCES, Science Bulletin, vol. i, no. 18. Cold Spring Harbor Monographs, no. 7. _ GEOLOGICAL SURVEY OF BRITISH GUIANA, Geology of the Gold Fields of British Guiana. ILLINOIS STATE MUSEUM OF NATURAL HISTORY, Biennial Report, 1908. (ob) HUROPE SCHLESISCHE GESELLSCHAFT FUR VATERLANDISCHE CULTUR, 85 sten Jahresbericht, 1906. INSTITUTULUI GEOLOGIC AL ROUMANIEI, Anuarul, vol. i, fase. 3. Anuarul, vol. ii, fase. 1-2. DANSK GEOLOGISK FORENING, Meddelelser, nr. 14-15. ATLANTA COLUMBUS HARTFORD NORMAN TRENTON BROOKLYN GEORGETOWN SPRINGFIELD BRESLAU BUCHAREST COPENHAGEN 3314. 3481. 3506. 3407. 3485. 3382. 3045. (D) FRoM 3425. 3523. 3507. 3508. 3509. 3510. 3424, 3416. ACCESSIONS TO THE LIBRARY A9 ACADEMIE POLYTECHNICA, PORTO Annaes Scientificos, vol. iii, nos. 2-4. Annaes Scientificos, vol. iv, nos. 1-2. SECTION GEOLOGIQUE DU CABINET DE SA MAJESTE, SAINT PETERSBURG Travaux, vol. vii. UNIVERSITY OF UPSALA, UPSALA Bulletin of the Geological Institution, vol. viii. GEOLOGISCHE GESELLSCHAFT, WIEN Mittheilungen, band ii, heft 1. (c) ASIA TOKYO GEOGRAPHICAL SOCIETY, TOKYO Journal of Geography, vol. xx, 1908. IMPERIAL UNIVERSITY OF TOKYO, TOKYO Journal of the College of Science, vol. xxvi, article 2. FELLOWS OF THE GEOLOGICAL SOCIETY OF AMERICA (PERSONAL PUBLICATIONS ) BASSLER, R. S. Cement Materials of Western Virginia. The Formation of Geodes. Late Niagaran Strata of West Tennessee. COSTE, EUGENE Petroleums and Coals. CROSS, WHITMAN Prowerose from Two Buttes, Colorado. Triassic Portion of the Shinarump Group. Stratigraphic Results of a Reconnaissance in Western Colorado and Utah. The Laramie Formation and the Shoshone Group. GRANT, U. S., AND PURDUE, M. J. Millbrig Sheet of the Lead and Zinc District of Northwestern IIli- nois. HITCHCOCK, C. H. Geology of the Hanover, N. H., Quadrangle. LXVI—BULL. GEOL. Soc. AM., Vou. 20, 1908 720 3431. 3002. oz. 3408-3411. D000. 3478. PROCEEDINGS OF THE BALTIMORE MEETING WALCOTT, C. D. Cambrian Geology and Paleontology, no. 5. Mount Stephen Rocks and Fossils. (H#) FRomM MISCELLANEOUS SOURCES MICHEL MOURLON, Nine Separates. SURVEY OF INDIA, parts: 1, 4. ULRICO HOEPLI, . Metallografia; Manuali Hoepli; Ing. U. Savoia. . Lo Zinco; Manuali Hoepli; Prof. R. Musu. Boy. . REPUBLICA ORIENTAL DEL URUGUAY, Annuario Estadistico, tomo i. SCHOOL OF MINES, Annaes, nos. 2, 5, 7-9. D. EYDOUX AND L. MAURY, Les Glaciers orientaux du Pic Long. H. ARCTOWSKI, Les variations séculaires du Climat de Varsovie. BRUSSELS CALCUTTA . Geography and Geology of the Himalaya Mountains and Tibet, . Professional Paper no. 10, Pendulum Operations in India, 1903-1907. MILAN MONTEVIDEO OURO PRETO PARIS WARSAW LIST OF OFFICERS, CORRESPONDENTS, AND FELLOWS OFFICERS FOR 1909 President: GrovE K. GILBERT, Washington, D. C. Vice-Presidents: Frank D. Adams, Montreal, Canada JoHN M. CiarxKe, Albany, New York Secretary: Epmunp Otis Hovey, American Museum of Natural History, New Nore Na: Treasurer: Wm. Buttock CuiaRrK, Baltimore, Maryland Editor: J. STANLEY-Brown, Cold Spring Harbor, Long Island, N. Y. Labrarian: H. P. CusHine, Cleveland, Ohio Councilors: (Term expires 1909) H. HE. Grecory, New Haven, Connecticut H. F. Rerp, Baltimore, Maryland (Term expires 1910) H. P. Cusuine, Cleveland, Ohio H. B. Parton, Golden, Colorado (Term expires 1911) Gro. OT1s SmitrH, Washington, D. C. Henry 8S. Wasuineton, Locust, New Jersey (721) 122 PROCEEDINGS OF THE BALTIMORE MEETING MEMBERS, DECEMBER 31, 1909 CORRESPONDENTS CHARLES Barrois, D. és Se., D. Se, Lille, France. Professor of Geology at the University. December, 1909. W. C. Broecer, Se D., Ll. D., Christiania, Norway. Professor of Geology and Mineralogy at the Royal University. December, 1909. Str ARCHIBALD GEIKIE, D. C. L., Sc. D., LL. D., Hasslemere, England. Presi- dent of the Royal Society, late Director General of the Geological Society of the United Kingdom. December, 1909. ALBRECHT HEIM, D. Sc., Ziirich, Switzerland. President of the Swiss Geo- logical Commission and Professor of Geology at the University. December, 1909. EMANUEL Kayser, Ph. D., Marburg, Germany. Professor of Geology at the University. December, 1909. EpvuARD Suess, Ph. D., Vienna, Austria. Formerly Professor of Geology at the ~ Imperial Royal University, President of the Imperial Academy of Sci- ences. December, 1909. FERDINAND ZIRKEL, D. Sc., Ph. D., Konigstrasse 27, Bonn, Germany. Geheimer Rath, Professor (retired) of Mineralogy and Geology at the University of Leipzig. December, 1909. FELLOWS *Indicates Original Fellow (see article III of Constitution) CLEVELAND ABBE, JR., Ph. D., U. S. Weather Bureau, Washington, D. C. August, 1899. FRANK Dawson ApDAMS, Ph. D., Montreal, Canada; Professor of Geology in McGill University. December, 1889. GEORGE I. ADAMS, Sc. D., Bureau of Mines, Manila, P. I. December, 1902. JOSE GUADALUPE AGUILERA, Ph. D., City of Mexico, Mexico; Director del In- stituto Geologico de Mexico. August, 1896. TRUMAN H. AtpricH, M. E., 1739 P St. N. W., Washington, D. C. May, 1889. Henry M. Ami, A. M., Ottawa, Canada; Assistant Paleontologist on Geo- logical and Natural History Survey of Canada. December, 1889. FRANK M. ANDERSON, B. A., M. S., 2604 tna Street, Berkeley, Cal. Cali- fornia State Mining Bureau. June, 1902. PuHILip ARGALL, 728 Majestic Building, Denver, Colo. August, 1896. RALPH ARNOLD, Ph. D., 726 H. W. Hellman Bidg., Los Angeles, Cal. Decem- ber, 1904. GEORGE Hatt ASHLEY, M. E., Ph. D., Washington, D. C.; U. S. Geological Survey. August, 1895. RUFUS MATHER Bace, JrR., Ph. D., 603 W. Green St., Urbana, Ill.; Instructor in Geology in University of Illinois. December, 1896. Harry Foster Bain, M. S.. 667 Howard St., San Francisco. Cal. December, 1895. S. PRENTISS BALDWIN, 736 Prospect St., Cleveland. Ohio. August, 1895. FELLOWS 123 SypNEY H. Bat, A. B., 71 Broadway, New York City. December, 1905. HRwIN HINCKLEY Barsour, Ph. D., Lincoln, Neb.; Professor of Geology, Uni- versity of Nebraska, and Acting State Geologist. December, 1896. ; ALFRED ERNEST Bartow, B. A., M. A., D. Sce., 24 Durochen St., Montreal, Canada. December, 1906. JOSEPH BARRELL, Ph. D., New Haven, Conn.; Professor of Structural Geology. Yale University. December, 1902. GEORGE H. Barton, B. S., Boston, Mass.; Curator, Boston Society of Natural History. August, 1890. FLORENCE Bascom, Ph. D., Bryn Mawr, Pa.; Professor of Geology, Bryn Mawr College. August, 1894. | Ray SMITH BASSLER, B. A., M. S., Ph. D., Washington, D. C.; U. S. National Museum. December, 1906. WILLIAM S. BayLey, Ph. D., Urbana, Ill.; Assistant Professor of Geology, University of Illinois. December, 1888. *GEORGE FE. BECKER, Ph. D., Washington, D. C.; U. S. Geological Survey. JOSHUA W. BEEDE, Ph. D., Bloomington, Ind.; Instructor in Geology, Indiana University. December, 1902. Rosert Be tL, I. S. O., Se. D., M. D., LL. D., F. R. S., Ottawa, Canada; Chief Geologist, Geological Survey, Department of Mines. May, 1889. CHARLES P. BERKEY, Ph. D., New York City; Instructor in Geology, Columbia University. August, 1901. SAMUEL WALKER BEYER, Ph. D., Ames, Iowa; Assistant Professor in Geology, Iowa Agricultural College. December, 1896. ARTHUR B. Brissins, Ph. B., Baltimore, Md.; Instructor in Geology, Woman’s College. December, 1903. ALBERT S. BicKMoRE, Ph. D., 863 Seventh Ave., New York City; Curator Emeritus, Department of Public Instruction, American Museum of Nat- ural History. December, 1889. Irvine P. BisHop, 109 Norwood Ave., Buffalo, N. Y.; Professor of Natural Science, State Normal and Training School. December, 1899. ELLIOT BLACKWELDER, A. B., Madison, Wis.; Assistant Professor of Geology in University of Wisconsin. December, 1908. WILLIAM PuHIpres BLAKgsE, Ph. B., Tucson, Arizona; Director School of Mines, Arizona, and Territorial Geologist. December, 1908. JOHN M. BoutTweEt., M. S., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. December, 1905. JOHN ADAMS BowNnockKER, D. Se., Columbus, Ohio; Professor of Inorganic Geology, Ohio State University. December, 1904. *JOHN C. BRANNER, Ph. D., Stanford University, Cal.; Professor of Geology in Leland Stanford, Jr., University. ALBERT PERRY BrRIGHAM, A. B., A. M., Hamilton, N. Y.; Professor of Geology and Natural History, Colgate University. December, 1893. REGINALD W. Brock, M. A., Ottawa, Canada; Director, Geological Survey, Department of Mines. December, 1904. ALFRED HULSE Brooks, B. S., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. August, 1899. Amos P. Brown, Ph. D., Philadelphia, Pa.; Professor of Mineralogy and Geology, University of Pennsylvania. December, 1905. (24 PROCEEDINGS OF THE BALTIMORE MEETING CHARLES WILSON Brown, Ph. D., A. M., Providence, R. I.; Assistant Professor and Head of the Department of Geology in Brown University. Decem- ber, 1908. ERNEST ROBERTSON BUCKLEY, Ph. D., Rolla, Mo. June, 1902. *SAMUEL CALVIN, Ph. D., LL. D., lowa City, Iowa; State Geologist; Professor of Geology in the State University of Iowa. HENRY DONALD CAMPBELL, Ph. D., Lexington, Va.; Professor of Geology and Biology in Washington and Lee University. May, 1889. Marius R. CAMPBELL, Washington, D. C.; U. S. Geological Survey. August, 1892. FRANK CaRNEY, A. B., Granville, Ohio; Professor of Geology in Denison Uni- versity. December, 1908. FRANKLIN R. CARPENTER, Ph. D., 1420 Josephine St., Denver, Colo. May, 1889. ERMINE C. Casz, Ph. D., Ann Arbor, Mich.; Department of Geology, Univer- sity of Michigan. December, 1901. *T. C. CHAMBERLIN, LL. D., Chicago, Ill.; Head Professor of Geology, Univer- sity of Chicago. CLARENCE RAYMOND CLAGHORN, B. S., M. H., Tacoma, Wash. August, 1891. FREDERICK G. CLAPP, S. B., 610 Fitzsimmons Bldg., Pittsburgh, Pa. Dec., 1905. “WILLIAM BULLOCK CLARK, Ph. D., Baltimore, Md.; Professor of Geology in Johns Hopkins University; State Geologist. JOHN MASON CLARKE, A. M., Ph. D., Albany, N. Y.; State Paleontologist. De- cember, 1897. HERDMAN F. CLELAND, Ph. D., Williamstown, Mass.; Professor of Geology, Williams College. December, 1905. J. MORGAN CLEMENTS, Ph. D., Room 1707, 42 Broadway, New York City. De- cember, 1894. CoLLIER Coss, A. B., A. M., Chapel Hill, N. C.; Professor of Geology in Uni- versity of North Carolina. December, 1894. ARTHUR P. CoLEMAN, Ph. D., Toronto, Canada; Professor of Geology, Toronto University, and Geologist of Bureau of Mines of Ontario. December, 1896. GEORGE L. CoLLiz, Ph. D., Beloit, Wis.; Professor of Geology in Beloit College. December, 1897. ARTHUR J. CoLuier, A. M., S. B., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. June, 1902. *THEODORE B. Comstock, Se. D., Los Angeles, Cal. EUGENE Coste, B. és-Se, E. M., Toronto, Canada. December, 1906. *FRANCIS W. CRAGIN, Ph. D., Colorado Springs, Colo.; Professor of Geology {n Colorado College. ALJA ROBINSON Crook, Ph. D., Springfield, Ill.; State Museum of Natural History. December, 1898. * WILLIAM O. Crossy, B. S., Boston, Mass.; Professor of Geology in Massachu- setts Institute of Technology. WHITMAN Cross, Ph. D., Washington, D. C.; U. S. Geological Survey. May, 1889. GarRy E. Cutver, A. M., 1104 Wisconsin St., Stevens Point, Wis. December, 1891. Epnear R. Cuminas, Ph. D., Bloomington, Ind.; Professor of Geology, Indiana University. August, 1901, FELLOWS 725 *HeNRY P. CusuHine, M. S., Ph. D., Adelbert College, Cleveland, Ohio; Pro- fessor of Geology, Western Reserve University. REGINALD A. Daty, Ph. D., Boston, Mass.; Massachusetts Institute of Tech- nology. December, 1905. EDWARD SALISBURY DANA, A. B., A. M., Ph. D., 24 Hillhouse Ave., New Haven, Conn.; Professor of Physics and Curator of Mineralogical Collection in Yale University. December, 1908. *NELSON H. Darton, Washington, D. C.; U. S. Geological Survey. *WILLIAM M. Davis, S. B., M. E., Cambridge, Mass.; Sturgis-Hooper Professor of Geology in Harvard University. Davip T. Day, Ph. D., Washington, D. C.; U. S. Geological Survey. August, 1891. ORVILLE A. Dersy, M. S., No. 80 Rua Visconde do Rio Branco, Sao Paulo. Brazil. December, 1890. *JOSEPH S. DiL_erR, B. S., Washington, D. C.; U. S. Geological Survey. EDWARD V. D’INVILLIERS, H. M., 506 Walnut St., Philadelphia, Pa. December, 1888. RicHarp BE. Dopar, A. M., New York City; Professor of Geography in Teach- ers’ College. August, 1897. NoAaH FIELDS Drake, Ph. D., Tientsin, China; Professor of Geology in Im- perial Tientsin University. December, i898. JOHN ALEXANDER DRESSER, B. A., M. A., Ottawa, Ontario, Canada. Geologist, Geological Survey of Canada. December, 1906. CHARLES R. Dryer, M. A., M. D., Terre Haute, Ind.; Professor of Geography, Indiana State Normal School. August, 1897. *EDWIN T. DUMBLE, 1306 Main St., Houston, Texas. CLARENCE EpWARD Dutton, A. B., Englewood, N. J.; Major, U. S. A. (retired). December, 1907. ARTHUR S. HAKLE, Ph. D., Berkeley, Cal.; Instructor in Mineralogy, Univer- sity of California. December, 1899. CHARLES R. EASTMAN, A. M., Ph. D., Cambridge, Mass.; In Charge of Verte- brate Paleontology, Museum of Comparative Zoology, Harvard University. December, 1895. EpwIn C. EckEL, B. S., C. E., Munsey Building, Washington, D. C. December, 1905. ARTHUR H. ELFTMAN, Ph. D., P. O. Box 601, Tonopah, Nevada. Dec., 1898. *BENJAMIN K. EMERSON, Ph. D., Amherst, Mass.; Professor in Amherst College. *SAMUEL FE’. Emmons, A. M., EH. M., Washington, D. C.; U.S. Geological Survey. JOHN EYERMAN, F. Z. S., Oakhurst, Easton, Pa. August, 1891. HarRoLp W. FAIRBANKS, B. S., Berkeley, Cal.; Geologist State Mining Bureau. August, 1892. *HERMAN L. FAIRCHILD, B. S., Rochester, N. Y.; Professor of Geology in Unt- versity of Rochester. OLIVER C. FARRINGTON, Ph. D., Chicago, Ill.; Curator of Geology, Field Museum of Natural History. December, 1895. NEVIN M. FENNEMAN, Ph. D., Cincinnati, Ohio; Professor of Geology, Univer- sity of Cincinnati. December, 1904. Cassius ASA FisHer, A. B., A. M., 1832 Baltimore St. N. W., Washington, D. C.; U. S. Geological Survey. December, 1908, 726 PROCEEDINGS OF THE BALTIMORE MEETING Aveust F. Forerste, Ph. D., 417 Grand Ave., Dayton, Ohio; Teacher of Sciences, ' Steele High School. December, 1899. WILLIAM M. FontTAINe, A. M., Charlottesville, Va.; Professor of Natural His- tory and Geology in University of Virginia. December, 1888. Myron LESLIE FULLER, S. B., 104 Belmont Ave., Brockton. Mass. December, 1898. HengY STEWART GANE, Ph. D., Santa Barbara, Cal. December, 1896. HenRyY GANNETT, S. B., A. Met. B., Washington, D. C.; U. S. Geological Sur- vey. December, 1891. RUSSELL D. GrorceE, A. B., A. M., Boulder, Colo.; Professor of Geology, Uni- versity of Colorado. December, 1906. *GROVE K. GILBERT, A. M., LL. D., Washington, D. C.; U. S. Geological Survey. ADAM CAPEN GitL, Ph. D., Ithaca, N. Y.: Assistant Professor of Mineralogy and Petrography in Cornell University. December, 1888. L. C. GLENN, Ph. D., Nashville, Tenn.; Professor of Geology in Vanderbilt University. June, 1900. CHARLES H. Gorpon, Ph. D., Knoxville, Tenn. ; Professor of Geology and Min- eralogy in the University of Tennessee. August, 1893. CHARLES NEWTON GOULD, A. M.. Norman, Okla.; Professor of Geology, Univer- sity of Oklahoma. December. 1904. AMADEUS W. GRABAU. S. M., S. D., New York City: Professor of Paleontology, Columbia University. December, 1898. ULyYsses SHERMAN GRANT, Ph. D.. Evanston, Ill.; Professor of Geology. North- western University. December. 1890. HERBERT E. Grecory, Ph. D., New Haven, Conn.; Silliman Professor of Geol- ogy, Yale University. August, 1901. GEORGE P. GrRimsLey. Ph. D., Martinsburg, W. Va.: Assistant State Geologist, Geological Survey of West Virginia. August, 1895. Leon S. Griswoxp,. A. B., Rolla, Missouri. August, 1902. FREDERIC P. GULLIVER, Ph. D., Norwichtown. Conn. August, 1895. ARNOLD Hacue, Ph. B., Washington, D. C.; U. S. Geological Survey. Mary, 1889. *CHRISTOPHER W. Hatt, A. M.. 803 University Ave., Minneapolis, Minn.: Pro- fessor of Geology and Mineralogy in University of Minnesota. (GILBERT D. Haprets. Ph. B.. Ithaca, N. Y.; Assistant Professor of Paleontology and Stratigraphic Geology, Cornell University. December. 1903. JOHN BuRCHMORE Harrison, M. A., F. I. C., F. G. S., Georgetown. British Guiana; Government Geologist. June. 1902. JoHN B. Hastines, M. E., 1480 High St., Denver, Colo. May, 1889. *ERASMUS HawortTH, Ph. D., Lawrence, Kans.; Professor of Geology, Univer- sity of Kansas. C. WILLARD Hayes, Ph. D., Washington, D. C.; U. S. Geological Survey. May, 1889. RICHARD R. Hice, B. S., Beaver, Pa. December, 1903. *EUGENE W. Hrearp, Ph..D., LL. D., 2728 Bancroft Way, Berkeley, Cal.; Pro- fessor of Agriculture in University of California. FRANK A. Hitt, Roanoke, Va. May. 1889. *ROBERT T. Hitt. B. S., 25 Broad St., New York City. RicHARD C. Hitts, Denver, Colo. August, 1894. FELLOWS TOT *CHARLES H. Hircucock, Ph. D., LL. D., Honolulu, Hawaiian Islands; Pro- fessor Emeritus of Geology in Dartmouth College, Hanover, N. H. WILLIAM Hersert Hosss, Ph. D., Ann Arbor, Mich.; Professor of Geology, University of Michigan. August, 1891. *LEVI Hoiprook, A. M., P. O. Box 536, New York City. ARTHUR HoLiickK, Ph. D., Bronx Park, New York City; Assistant Curator, Department of Fossil Botany, New York Botanical Garden. August, 1893. * JOSEPH A. HotmeEs, Washington, D. C.; in charge of investigation of fuels and structural materials, U. S. Geological Survey. THOMAS C. Hopkins, Ph. D., Syracuse, N. Y.; Professor of Geology, Syracuse University. December, 1894. *HDMUND OTIS Hovey, Ph. D., New York City; Curator of Geology and Inverte- brate Paleontology, American Museum of Natural History. *THIORACE C. Hovey, D. D., Newburyport, Mass. ERNEST Howe, Ph. D., 75 Kay St., Newport, R. I.; Assistant Geologist, U. S. Geological Survey. December, 1903. *EpwIn BE. HoweELt, A. M., 612 Seventeenth St. N. W., Washington, D. C. Lucius L. Huspparp, Ph. D., LL. D., Houghton, Mich. December, 1894. ELLSWORTH HUNTINGTON, A. B., A. M., New Haven, Conn.; Instructor in Geography, Yale University. December, 1906. JOSEPH P. IppinGs, Ph. B., Chicago, Ill.; Professor of Petrographic Geology, University of Chicago. May, 1889. JOHN D. IrvinG, Ph. D., New Haven, Conn.; Professor of Economic Geology, Yale University. December, 1905. A. WENDELL JACKSON, Ph. B., 482 Saint Nicholas Ave., New York City. De- cember, 1888. Rospert JT. JACKSON, S. D., 9 Fayerweather St., Cambridge, Mass.; Assistant Professor in Paleontology in Harvard University. August, 1894. THOMAS M. Jackson, C. E., S. D., Clarksburg, W. Va. May, 1889. THOMAS AUGUSTUS JAGGAR, JR., A. B., A. M., Ph. D., Boston, Mass.; Professor of Geology, Massachusetts Institute of Technology. December, 1906. - MarK S. W. JEFFERSON, A. M., Ypsilanti, Mich.; Professor of Geography, Michigan State Normal College. December, 1904. ALBERT JOHANNSEN, B. S., Ph. D., Chicago, IN.; Department of Geology, Uni- versity of Chicago. December, 1908. DovUGLAS WILSON JOHNSON, B. S., Ph. D., Cambridge, Mass.; Assistant Pro- fessor of Physiography, Harvard University. December, 1906. ALEXIS A. JULIEN, Ph. D., New York City; Curator (emeritus) in Geology in Columbia University. May, 1889. GEORGE FREDERICK Kay, M. A., Iowa City, Iowa; Professor of Mineralogy, Petrography, and Economic Geology in State University of Iowa. De- cember, 1908. ARTHUR KeEITH, A. M., Washington, D. C.; U. S. Geological Survey. May, 1889, *JAMES FE. Kemp, A. B., EH. M., New York City; Professor of Geology in Colum- bia University. CHARLES ROLLIN Keyes, Ph. D., 944 Fifth St., Des Moines, Iowa. August, 1890. Epwarp M. KINpLE, Ph. D., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. December, 1905. 728 PROCEEDINGS OF THE BALTIMORE MEETING FRANK H. KNow tron, M. S., National Museum, Washington, D. C.; Assistant Paleontologist, U. S. Geological Survey. May, 1889. EDWARD HENRY Kraus, Ph. D., Ann Arbor, Mich.; Junior Professor of Min- eralogy, University of Michigan. June, 1902. HENRY B. KUMMEL, Ph. D., Trenton, N. J.; State Geologist. December, 1895. *GEORGE F. Kunz, A. M. (Hon.), Ph. D. (Hon.), care of Tiffany & Co., Fifth Ave., at 37th St., New York City. GEORGE HpGarR LApp, Ph. D., Rolla, Mo. August, 1891. J. C. K. LAFLAMME, M. A., D. D., Quebec, Canada; Professor of Mineralogy and Geology in Laval University, Quebec. August, 1890. HeENRY LANDES, A. B., A. M., University Station, Seattle, Wash.; Professor of Geology in University of Washington. December, 1908. ALFRED C. LANE, Ph. D., Tufts College, Mass.; Pearson Professor of Geology in Tufts College. December, 1889. ANDREW C. LAwson, Ph. D., Berkeley, Cal.; Professor of Geology and Miner- alogy in the University of California. May, 1889. Wititis THOMAS LEE, M. S., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. December, 1903. . CHARLES K. LEITH, Ph. D., Madison, Wis. ; Professor of Geology, University of Wisconsin; Assistant Geologist, U. S. Geological Survey. December, 1902. ARTHUR G. LEONARD, Ph. D., Grand Forks, N. Dak.; Professor of Geology and State Geologist, State University of North Dakota. December, 1901. FRANK LEVERETT, B. S., Ann Arbor, Mich.; Geologist, U. S. Geological Survey. August, 1890. i JOSEPH VOLNEY LEwIs, B. E., S. B., New Brunswick, N. J.; Professor of Geology, Rutgers College. December, 1906. WILLIAM LispBEy, Sc. D., Princeton, N. J.; Professor of Physical Geography in Princeton University. August, 1899. WALDEMAR LINDGREN, M. H., Washington, D. C.; U. S. Geological Survey. August, 1890. GEORGE DAvis LOUDERBACK, Ph. D., Berkeley, Cal.; Associate Professor of Geology, University of California. June, 1902. “Rosert H. LouGuripGE, Ph. D., Berkeley, Cal.; Assistant Professor of Agricult- ural Chemistry in University of California. May, 1889. ALBERT P. Low, B. A. Se., LL. D., Ottawa, Canada; Deputy Minister, Depart- ment of Mines. December, 1905. HirnAM DEYER McCaSskKEy, B. S., Washington, D. C.; U. S. Geological Survey. December, 1904. RICHARD G. McConngELL, A. B., Ottawa, Canada; Geologist on Geological and Natural History Survey of Canada. May, 1889. JAMES RIEMAN MACFARLANE, A. B., 100 Diamond St., Pittsburg, Pa. August, 1891. *W J McGes, LL. D., Washington, D. C.; Inland Waterways Commission. WILLIAM McInngss, A. B., Ottawa, Canada; Geologist, Geological and Natural History Survey of Canada. May, 1889. Peter McKeEtuar, Fort William, Ontario, Canada. August, 1890. Curtis F. Marsut, A. M., Columbia, Mo.; Professor of Geology in State Uni- versity and Assistant on Missouri Geological Survey. August, 1897. FELLOWS 729 VERNON F. Marsters, A. M., Apartado 856, Lima, Peru. August, 1892. GEORGE CuRTIS MARTIN, Ph. D., Washington, D. C.; U. S. Geological Survey. June, 1902. Hpwarp B. MatTHEws, Ph. D., Baltimore, Md.; Professor of Mineralogy and Petrography in Johns Hopkins University. August, 1895. W. D. MattrHew, Ph. D., New York City; Associate Curator of Vertebrate Paleontology, American Museum of Natural History. December, 1903. P. H. Mettz, M. E., Ph. D., 165 East 10th St., Atlanta, Ga. December, 1888. WALTER C. MENDENHALL, B. S., Washington, D. C.; Geologist, U. S. Geological Survey. June, 1902. JOHN C. MeERRIAM, Ph. D., Berkeley, Cal.; Instructor in Paleontology in Uni- . versity of California. August, 1895. *WREDERICK J. H. MERRILL, Ph. D., Nogales, Arizona. GEORGE P. MerRRILL, Ph. D., Washington, D. C.; Curator of Department of Lithology and Physical Geology in U. S. National Museum. December, 1888. ARTHUR M. MILLER, A. M., Lexington, Ky.; Professor of Geology, State Uni- versity of Kentucky. December, 1897. BENJAMIN L. MILLER, Ph. D., South Bethlehem, Pa.; Professor of Geology, Lehigh University. December, 1904. WILLET G. Mitier, M. A., Toronto, Canada; Provincial Geologist of Ontario. December, 1902. Henry Montcomery, Ph. D., Toronto, Canada; Curator of Museum, Univer- sity of Toronto. December, 1904. *FRANK L. Nason, A. B., West Haven, Conn. Davip HALE NEWLAND, B. A., Albany, N. Y.; Assistant State Geologist. De- cember, 1906. JoHN F. Newsom, Ph. D., Stanford University, Cal.; Associate Professor of Mining in Leland Stanford, Jr., University. December, 1899. Wittiam H. Nites, Ph. D., M. A., Boston, Mass.; Professor Emeritus of Geology, Massachusetts Institute of Technology; Professor of Geology. Wellesley College. August, 1891. WILLIAM H. Norton, M. A., Mount Vernon, Iowa; Professor of Geology in Cornell College. December, 1895. CHARLES J. Norwoop, Lexington, Ky.; Professor of Mining, State University of Kentucky. August, 1894. IpA HELEN OcILvIE, A. B., Ph. D., New York City; Tutor in Geology, Barnara College, Columbia University. December, 1906. CLEOPHAS C. O’HarrRA, Ph. D., Rapid City, S. Dak.; Professor of Mineralogy and Geology, South Dakota School of Mines. December, 1904. EZEQUIEL ORDONEZ, 2 a General Prime, Mexico, D. F., Mex. August, 1896. *Amos O. Osporn, Waterville, Oneida county, N. Y. Henry F. Osporn, Se. D., New York City; President of the American Museum of Natural History. August, 1894. CHARLES PaLACcHE, B. S., Cambridge, Mass.; Instructor in Mineralogy, Har- vard University. August, 1897. WILLIAM A. Parks, B. A., Ph. D., Toronto, Canada; Associate Professor of Geology, University of Toronto. December, 1906. 730 PROCEEDINGS OF THE BALTIMORE MEETING *HoraceE B. Patton. Ph. D., Golden. Colo.; Professor of Geology and Mineral- ogy in Colorado School of Mines. FREDERICK B. PEcK, Ph. D., Easton, Pa.: Professor of Geology and Mineralogy. Lafayette College. August, 1901. DAviD PEARCE PENHALLOW, B. S., M. S.. Sc. D., Montreal, Canada; Professor of Botany in McGill University. December, 1907. RICHARD A. F. PENROSE, JR.. Ph. D., 460 Bullitt Building, Philadelphia, Pa. May, 1889. GeorGE H. PerKins. Ph. D.. Burlington, Vt.; State Geologist; Professor of Geology, University of Vermont. June. 1902. JOSEPH H. Perry, 276 Highland St.. Worcester. Mass. December, 1888. Louts Y. Pirsson, Ph. D., New Haven, Conn.: Professor of Physical Geology- Sheffield Scientific School of Yale University. August, 1894. JOSEPH Hype Pratt. Ph. D., Chapel Hill, N. C.: Mineralogist, North Carolina Geological Survey. December. 1898. *CHARLES S. Prosser. M. S., Columbus, Ohio; Professor of Geology in Ohio State University. *RAPHAEL PUMPELLY. Newport, R. I. ALBERT HomMeER PurRpvueE, B. A., Fayetteville, Ark.: Professor of Geology, Uni- versity of Arkansas. December, 1904. FREDERICK LESLIE RANSOME, Ph. D., Washington, D. C.: Geologist. U. S. Geo- logical Survey. August, 1895. Percy EDWARD RAYMOND, B. A., Ph. D., Pittsburgh, Pa.; Assistant Curator of Invertebrate Fossils in the Carnegie Museum. December. 1907. Harry FIELDING REID, Ph. D., Baltimore, Md.: Professor of Geological Physics, Johns Hopkins University. December, 1892. WILLIAM NorTtTH Rice, Ph. D., LL. D., Middletown, Conn.: Professor of Geol- ogy in Wesleyan University. August, 1890. CHARLES H. RicHARDSON, Ph. D., Syracuse. N. Y.: Assistant Professor of Geology and Mineralogy. Syracuse University. December, 1899. GEORGE BurRR RIcHARDSON, §. B., 8. M., Ph. D., Washington, D. C.: U. S. Geo- logical Survey. December, 1908. HeEINRIcH Ries. Ph. D., Ithaca, N. Y.: Professor of Economic Geology in Cornell University. December, 1893. RUDOLPH RUEDEMANN, Ph. D., Albany, N. Y.: Assistant State Paleontologist. December. 1905. ORESTES H. St. JoHn, 1141 Twelfth St.. San Diego. Cal. May. 1889. *ROLLIN D. Satispury, A. M., Chicago, [ll.: Professor of General and Geo- graphic Geology in University of Chicago. FREDERICK W. SARDESON, Ph. D., Minneapolis. Minn.; Assistant Professor of Geology. University of Minnesota. December, 1892. THOMAS EpMunNpD SaAvace, A. B., B. S.. M. S.. Urbana, [ll.: Department of Geology. University of Illinois. December, 1907. FRANK C. ScHrRapeEr, M. S., A. M., Washington, D. C.: U. S. Geological Survey. August, 1901. CHARLES SCHUCHERT, New Haven. Conn.: Professor of Paleontology. Yale University. August, 1895. WiILiIAmM B. Scott, Ph. D., 56 Bayard Ave.. Princeton, N. J.: Blair Professor of Geology in Princeton University. August, 1892. FELLOWS (ol ARTHUR EDMUND SEAMAN, B. S., Houghton, Mich.; Professor of Mineralogy and Geology, Michigan College of Mines. December, 1904. Henry M. Srety, M. D., Middlebury, Vt.; Professor of Geology in Middlebury College. May, 1889. ELias H. SELLaRDS, Ph. D., Tallahassee, Fla.; State Geologist. December, 1905. JOAQUIM CANDIDO DA Costa SENA, Ouro Preto, Brazil; Director of the State School of Mines and Professor of Mineralogy and Geology. December, 1908. GEORGE BURBANK SHATTUCK, Ph. D., Poughkeepsie, N. Y.; Professor of Geology in Vassar College. August, 1899. SoLon SHeEpDpD, A. B., Pullman, Wash.; Professor of Geology and Mineralogy, Washington Agricultural College. December, 1904. EpwARD M. SHEPARD, Sc. D., Springfield, Mo.; Professor of Geology, Drury College. August, 1901. WILL H. SHeERzER, M. S., Ypsilanti, Mich.; Professor in State Normal School, December, 1890. BoHUMIL SHIMEK, C. H., M. S., Iowa City, Iowa; Professor of Physiological Botany, University of Iowa. December, 1904. *HREDERICK W. SIMONDS, Ph. D., Austin, Texas; Professor of Geology in Uni- versity of Texas. WILLIAM JOHN SINCLAIR, B. S., Ph. D., Princeton, N. J.; Instructor in Prince- ton University. December, 1906. EARLE SLOAN, Charleston, S. C.; State Geologist of South Carolina. Decem- ber, 1908. *HuGENE A. SmITH, Ph. D., University, Tuscaloosa county, Ala.; State Geol- ogist and Professor of Chemistry and Geology in University of Alabama. FRANK CLEMES SmitH, EH. M., Richland Center, Wis. December, 1898. GEORGE OTIS SMITH, Ph. D., Washington, D. C.; Director, U. S. Geological Sur- vey. August, 1897. WiLuiaM S. T. SmirH, Ph. D., 8389 Lake St., Reno, Nev.; Associate Professor of Geology and Mineralogy, University of Nevada. June, 1902. *JOHN C. Smock, Ph. D., Trenton, N. J. CHARLES H. SmMytTH, Jr., Ph. D., Princeton, N. J.; Professor of Geology in Princeton University. August, 1892. Henry L. SmMytuH, A. B., Cambridge, Mass.; Professor of Mining and Metal- lurgy in Harvard University. August, 1894. ARTHUR COE SPENCER, B. S., Ph. D., Washington, D. C.; Assistant Geologist, U. S. Geological Survey. December, 1896. *J. W. SPENCER, Ph. D., 2019 Hillyer Place, Washington, D. C. JOSIAH HK. Spurr, A. B., A. M., 165 Broadway, New York City. December, 1894. JOSEPH STANLEY-BRowNn, Cold Spring Harbor, Long Island, N. Y. August, 1892. TIMOTHY WILLIAM STANTON, B. S., U. S. National Museum, Washington, D. C.; Assistant Paleontologist, U. S. Geological Survey. August, 1891. *JOHN J. STEVENSON, Ph. D., LL. D., 568 West End Ave., New York City. GEORGE WILLIS Sroseg, B. S., Washington, D. C.; U. S. Geological Survey. De- cember, 1908. 732 PROCEEDINGS OF THE BALTIMORE MEETING WILLIAM J. SuTTON, B. S., E. M., Victoria, B. C.; Geologist to EB. and N. Rail- way Co. August, 1901. CHARLES KEPHART SwARTz, A. B., Ph. D., Baltimore, Md.; Associate Professor of Geology in Johns Hopkins University. December, 1908. JOSEPH A. TaFF, B. S., Palo Alto, Cal.; Assistant Geologist, U. S. Geological Survey. August, 1895. JAMES E. TALMAGE, Ph. D., Salt Lake City, Utah; Professor of Geology in University of Utah. December, 1897. RALPH S. Tarr, Ithaca, N. Y.; Professor of Dynamic Geology and Physical Geography in Cornell University. August, 1890. FRANK B. Taytor, Fort Wayne, Ind. December, 1895. WILLIAM G. TicHT, M. S., Albuquerque, N. Mex. August, 1897. *JAMES E. Topp, A. M.,;, 113 Park St., Lawrence, Kas.; Assistant Geologist, U. S. Geological Survey. *HeENRY W. TURNER, B. S., Room 709, Mills Building, San Francisco, Cal. JOSEPH B. TYRRELL, M. A., B. Sc., Room 534, Confederation Life Bldg., Toronto, Canada. May, 1889. JOHAN A. UDDEN, A. M., Rock Island, Ill.; Professor of Geology and Natural History in Augustana College. August, 1897. EDWARD O. ULRIcH, D. Sce., Washington, D. C.; Assistant Geologist, U. S. Geo- logical Survey. December, 1903. *WARREN UPHAM, A. M., Saint Paul, Minn.; Librarian Minnesota Historical Society. *CHARLES R. VAN HISsE, M. S., Ph. D., Madison, Wis.; President University of Wisconsin; Geologist, U. S. Geological Survey. FRANK ROBERTSON VAN Horn, Ph. D., Cleveland, Ohio; Professor of Geology and Mineralogy, Case School of Applied Science. December, 1898. GILBERT VAN INGEN, Princeton, N. J.; Curator of Invertebrate Paleontology and Assistant in Geology, Brinceton University. December, 1904. THOMAS WAYLAND VAUGHAN. B. S., A. M., Washington, D. C.; Assistant Geol- ogist, U. S. Geological Survey. August, 1896. ARTHUR CLIFFORD VEACH, Washington, D. C.; Geologist, U. S. Geological Sur- vey. December, 1906. *ANTHONY W. VocGbEs, 2425 First St., San Diego, Cal.; Brigadier General, U. S. A. (Retired). *M. EpwaRD WADSWORTH, Ph. D., Pittsburgh, Pa.; Dean of the School of Mines in the University of Pittsburgh. *CHARLES D. WaxcoTT, LL. D., Washington, D. C.; Secretary Smithsonian Institution. THomas L. WALKER, Ph. D., Toronto, Canada; Professor of Mineralogy and Petrography, University of Toronto. December, 1903. CHARLES H. WARREN, Ph. D., Boston, Mass.; Instructor in Geology, Massachu- setts Institute of Technology. December, 1901. HENRY STEPHENS WASHINGTON, Ph. = Locust, Monmouth Co., N. J.; August, 1896. THomas L. Watson, Ph. D., Charlottesville, Va.; Professor of Geology in Unit- versity of Virginia. June, 1900. WALTER H. WEED, E. M., Norwalk, Conn. May, 1889. FRED. BoUGHTON WEEKS, Washington, D. C.; Assistant Geologist, U. S. Geolog- ical Survey. December, 1903. : FELLOWS 7838 SAMUEL WEIDMAN, Ph. D., Madison, Wis. ; Geologist, Wisconsin Geological and Natural History Survey. December, 1903. STUART WELLER, B. S., Chicago, Ill.; Associate Professor of Paleontologic Geology, University of Chicago. June, 1900. LEwIs G. WESTGATE, Ph. D., Delaware, Ohio; Professor of Geology, Ohio Wesleyan University. THOMAS C. WESTON, care of A. Patton, Levis, Quebec, Canada. August, 1893. Davip WuHuiTE, B. S., U. S. National Museum, Washington, D. C.; Geologist, U. S. Geological Survey. May, 1889. *ISRAEL C. WHITE, Ph. D., Morgantown, W. Va. *ROBERT P. WHITFIELD, A. M., New York City; Curator Emeritus of Geology | and Invertebrate Paleontology, American Museum of Natural History. FRANK A. WILDER, Ph. D., North Holston, Smyth Co., Va. December, 1905. *Hpwarp H. WILLIAMS, JR., A. C., E. M., Andover, Mass. — *HrenRyY S. WILLIAMS, Ph. D., Ithaca, N. Y.; Professor of Geology and Head of Geological Department, Cornell University. IrA A. WILLIAMS, M. Sc., Ames, Iowa; Teacher Iowa State College. Decem- ber, 1905. BAILEY WILLIS, Washington, D. C.; U. S. Geological Survey. December, 1889. SAMUEL W. WILLISTON, Ph. D., M. D., Chicago, Ill.; Professor of Paleontology, University of Chicago. December, 1889. ARTHUR B. WiLuLMorTT, M. A., 24 Adelaide St., W., Toronto, Canada. Decem- ber, 1899. ALFRED W. G. WILSON, Ph. D., Mines Branch, Department of Mines, Ottawa, Canada. June, 1902. ALEXANDER N. WINCHELL, Doct. U. Paris, Madison, Wis.; Professor of Geology and Mineralogy, University of Wisconsin. August, 1901. *HoRACE VAUGHN WINCHELL, 505 Palace Building, Minneapolis, Minn. *NEWTON H. WINCHELL, A. M., 501 Hast River Road, Minneapolis, Minn. *ARTHUR WINSLOW, B. S., 131 State St., Boston, Mass. JOHN EK. Wo rr, Ph. D., Cambridge, Mass. ; Professor of Petrography and Min- eralogy in Harvard University and Curator of the Mineralogical Museum. December, 1889. JOSEPH EH. WoopMAN, S. D., New York City; Professor of Geology in New York University. December, 1905. RosBert S. Woopwarp, C. H., Washington, D. C.; President of the Carnegie Institution of Washington. May, 1889. JAY B. WoopwortH, B. S., 24 Langdon St., Cambridge, Mass.; Assistant Pro- fessor of Geology, Harvard University. December, 1895. FREDERIC EH. WRIGHT, Ph. D., Washington, D. C.; Geophysical Laboratory, Car- negie Institution. December, 1903. *G. FREDERICK WRIGHT, D. D., Oberlin, Ohio; Professor in Oberlin Theological Seminary. GrEoRGE A. Youne, Ph. D., Ottawa, Canada; Geologist, Geological Survey of Canada. December, 1905. FELLOWS-ELECT WILLIAM CLINTON ALDEN, A. B., A. M., Ph. D., Washington, D. C. Assistant Geologist, U. S. Geological Survey. December, 1909. 734 PROCEEDINGS OF THE BALTIMORE MEETING WALLACE WALTER AtTwoop, B.S., Ph. D., Chicago, Illinois. Instructor at Uni- versity of Chicago and Assistant Geologist, U. S. Geological Survey. De- cember, 1909. EDSON SUNDERLAND BastTIN, A. B., A. M., Washington, D. C. Assistant Geolo- gist, U. S. Geological Survey. December, 1909. EpwARD WILBER Berry, Baltimore, Maryland. Instructor in Paleontology, Johns Hopkins University. December, 1909. WILLIS STANLEY BLATCHLEY, A. B., A. M., State House, Indianapolis, Indiana. State Geologist of Indiana. December, 1909. Henry ANDREW BUEHLER, B.S., Rolla, Missouri. State Geologist of Missouri. December, 1909. FRED HARVEY HALL CALHOUN, B.S., Ph. D., Clemson College, South Carolina. Professor of Geology and Mineralogy, Clemson College, and Assistant Geologist, U. S. Geological Survey. December, 1909. ARTHUR Louis Day, B.A., Ph. D., Washington, D. C. Director, Geophysical Laboratory, Carnegie Institution of Washington. December, 1909. FRANK WILBRIDGE DE WOLF, 8S. B., Urbana, Illinois. Assistant State Geologist of. Illinois and Assistant Geologist, U. S. Geological Survey. December, 1909. JAMES WALTER GOLDTHWAIT, A. B., A. M., Ph. D., Hanover, New Hampshire. Assistant Professor of Geology in Dartmouth College and head of depart- ment. December, 1909. BAIRD HALBERSTADT, Pottsville, Pennsylvania. Engineer and Geologist. De- cember, 1909. OscakR H. HERSHEY, Kellogg, Idaho. December, 1909. FREDERICK BREWSTER LOOMIS, B. A., Ph. D., Amherst, Massachusetts. Professor of Comparative Anatomy in Amherst College. December, 1909. RICHARD SWANN LULL, B.S., M.S., Ph. D., New Haven, Connecticut. Assistant Professor of Vertebrate Paleontology, Yale University. December, 1909. GEORGE ROGERS MANSFIELD, B.S., A. M., Ph. D., Evanston, Illinois. Assistant Professor of Geology, Northwestern University. December, 1909. LAWRENCE Martin, A. B., A. M., Madison, Wisconsin. Instructor in Geology, University of Wisconsin. December, 1909. SAMUEL WASHINGTON McCatuiz, Ph. B., Atlanta, Georgia. State Geologist of Georgia. December, 1909. WILLIAM JOHN MirtieER, S.B., Ph. D., Clinton, New York. Professor of Geology and Mineralogy in Hamilton College. December, 1909. MatcoLm JoHN Munn, Washington, D. C. Assistant Geologist, U. S. Geological Survey. December, 1909. EDWARD ORTON, JR., E.M., Columbus, Ohio. Assistant Geologist, Geological Survey of Ohio. December, 1909. Puiwip S. SmitH, A. B., A. M., Ph. D., Washington, D. C. Assistant Geologist, U. S. Geological Survey. December, 1909. WARREN Du PRE SmiTH, B.S., A. M., Ph. D., Manila, Philippine Islands. Chief of the Mining Bureau. December, 1909. CyRUS FISHER TOLMAN, JR., B.S., Tucson, Arizona. Professor of Geology and Mining in the University of Arizona. December, 1909. CHARLES WILL WricHT, B.S., M.E., Washington, D. C. Assistant Geologist, U. S. Geological Survey. December, 1909. : DECEASED MEMBERS 135 FELLOWS DECEASED “Indicates Original Fellow (see article III of Constitution) *CHARLES A. ASHBURNER, M. S., C. H. Died December 24, 1889. CHARLES E. BEECHER, Ph. D. Died February 14, 1904. Amos BowMAN. Died June 18, 1894. *J. H. CHapin, Ph. D. Died March 14, 1892. *EDWARD W. CLAYPOLE, D. Se. Died August 17, 1901. GEORGE H. Cook, Ph. D., LL. D. Died September 22, 1889. *KDWARD D. Corr, Ph. D. Died April 12, 1897. ANTONIO DEL CASTILLO. Died October 28, 1895. *JaAMES D. Dana, LL. D. Died April 14, 1895. GEORGE M. Dawson, D. Se. Died March 2, 1901. Sir J. WILLIAM Dawson, LL. D. Died November 19, 1899. *WiLLIAM B. Dwieut, Ph. B. Died August 29, 1906. *GEORGE H. ELpRiper, A. B. Died June 29, 1905. *ALBERT EH. Foote. Died October 10, 1895. *PERSIFOR FRAZER. Died April 7, 1909. *HomMER T. FULLER. Died August 14, 1908. N. J. Giroux, C. HE. Died November 30, 1890. *JAMES Hatt, LL. D. Died August 7, 1898. JOHN B. HatcHeEr, Ph. B. Died July 3, 1904. ~ *ROBERT Hay. Died December 14, 1895. *ANGELO HEILPRIN. Died July 17, 1907. Davip HONEYMAN, D. C. L. Died October 17, 1889. THOMAS STERRY Hunt, D. Se, LL. D. Died February 12, 1892. *ALPHEUS Hyatt, B. S. Died January 15, 1902. *JOSEPH F.. JAMES, M. S. Died March 29, 1897. WILBUR C. KNI@HT, B. S., A. M. Died July 28, 1903. RaLPH D. Lacor. Died February 5, 1901. DANIEL W. LANGTON. Died June 21, 1909. * JOSEPH LE ConTE, M. D., LL. D. Died July 6, 1901. *J. PreTER LESLEY, LL. D. Died June 2, 1903. | Henry McCattey, A. M., C. E. Died November 20, 1904. OLiveR Marcy, LL. D. Died March 19, 1899. OTHNIEL C. MarsH, Ph. D., LL. D. Died March 18, 1899. JAMES HE. MILLs, B. S. Died July 25, 1901. *HENRY B. Nason, M. D., Ph. D., LL. D. Died January 17, 1895. *PETER NEFF, M. A. Died May 11, 1903. *JoHN S. NeEwbBerry, M. D., LL. D. Died December 7, 1892. *HDWARD ORTON, Ph. D., LL. D. Died October 16, 1899. *RICHARD OwEN, LL. D. Died March 24, 1890. SAMUEL L. PENFIELD. Died August 14, 1906. KRRANKLIN PLaTT. Died July 24, 1900. WILLIAM H. Petter, A. M. Died May 26, 1904. *JOHN WESLEY POWELL, LL. D. Died September 23, 1902. *IsRAEL C. RUSSELL, LL. D. Died May 1, 1906. “JAMES M. SarrorD, M. D., LL. D. Died July 3, 1907. LXVII—BULL. Grou. Soc. AM., VOL. 20, 1908 736 PROCEEDINGS OF THE BALTIMORE MEETING *CHARLES SCHAEFFER, M. D. Died November 238, 1903. *NATHANIEL 8. SHALER, LL. D. Died April 10, 1906. CHARLES WACHSMUTH. Died February 7, -1896. THEODORE G. WHITE, Ph. D. Died July 7, 1901. *GEORGE H. WILLIAMS, Ph. D. Died July 12, 1894. *J. FRANCIS WILLIAMS, Ph. D. Died September 9, 1891. * ALEXANDER WINCHELL, LL. D. Died February 19, 1891. ALBERT A. WRIGHT, Ph. D. Died April 2, 1905. WILLIAM S. YEATES. Died February 19, 1908. Summary Original “Wellowsscses.s0¢. eee ba eee re Hlected: Fellows: 2. 2 ss 2<.46ch2decks bas 6 oe eee + eee 252 Membership .2..06:.2:s05 je cite ce ets eae eee ee eee 310 Deceased Mellows..: .. okie so ee ee ee eee eo ee eee 54 INDEX TO VOLUME 20 Page ADAMS, FRANK D., elected First Vice- FEAESUGE Mit, = ci sisee ol sos ediavn @ dials wears ees —, Gneisses ucrerred TOM Dic 6 crecdccera rs atacs 234 ——, Reference to. ... 156, 569, 668, 689 (and Alfred BR. Barlow), Title of ROA CLM Votes eyoren sree ate Glanarecss, wi eteie ores 621 ADIRONDACKS, Pleistocene Ue of the southwestern slope of the. oe AGASSIZ, LOUIS, Reference to........ AGUILERA, , Reference to...... 583, a AFTONIAN and Nebraskan—an ‘adden-. COLETTE. \ GRE ae eee teen, Ca Sear met ea 408 — beds in Iowa, Previously known dis- (ela OMG GE. oss cee. s s,s cee oe © 399, 400 — —, Evidence of .............. 404-407 — deposits, Hxtent of............ 343-344 — —, Stratigraphic position of.... 341-342 AO OM AA eter Aire sles eo cke oe ss wie dale ies 353 —fauna, Mammalian ........... 341-356 — gravels, Investigations by Shimek of. 137 — —, Mollusks and mammals of...... igs === IN@IPSOS).“olS: cso OREN ROR OL RCE NE mea a Corte 44—350U interval, Climate Of. ........6s0%. . 3843 NNO i cinlcs ess shee e Gisele w eee e ss 136 ——, Relation of gravels, in mers ie MO, yo. Mosc niin os —343 — interglacial with mild climate, The.. 406 — mammalian fauna, New material Ol 36 o OR eee eee 354-356 — — —, Localities of............ 343-344 — peat beds of Iowa, Location of.. 399, 4vU ICL OVOSCIGEANS .2 0-56 ee ccc eee 351-353 —sand and gravel beds, Description OMI esc x aleeter dose soars ces, —404 — —-— gravel beds of Iowa, Location OE 3% 610 68. OO Re ee ee 400 — — — gravels in western Iowa, ee ness and altitude of beds of. — — — — — western Iowa ...... "399-408 — — ——, Stratigraphic position of.. 404-406 —, T. C. Chamberlin first applied name. 399 — sands and gravels, Views of... 400-407 AFTON Junction, Fossils from......... 138 —, Older drift exposed at............ 136 ALASKA peninsula, Geologic studies in.. 700 ALBERTAN drift, Reference to.......... 135 ALDEN, WILLIAM C., Criteria for age of glacial drift sheets (abstract).... 638 —, Glacial phenomena of southeastern Wisconsin: (abstract) 2... cesce.s 638 —=3, JRGTRANG 10) an ogogomudooo UU oot 702 ATHEORMEIUNSS MGOOMS ene moe gous aenoe6 a6 239 AMERICAN Association for the Advance- ment of Science, Titles of papers presented before Section E of. 703-704 — Journal of Science, Reference to.... 410 — Museum of Natural History, Refer- ence to 1902, 1903, and 1908 expe- ditions for.. 409, 412, 417, 418, 419, 421 Amr, H. M., Reference to........ "430, 556, 572, 689, 701 AN AESHSes GnlOrOpal .). 5 .1c0 6 «1 © 5 263 == 5 Diol GH Bas scunade sania) Ga) overtene 237 == 9 (GHERINITIGS ae Sie circrn Hicoidic Sida 251 —= 2 IDB DIIEShaj Ag) Sooo ooooodooodc 257 me AOE EAN ALL LEVEL aisis <\cheis os «sue seers oss LGL —: Piper Peak basalt.......... Sayers —:Quartz-monzonite ....... sPstay Svavevoneno On MTU TIV OTS eo taylaeic ce hoais es 1p iin’ oa ewrene scelonene . 160 SE POVESUVIANITE, «acces. ccceee svete eee OM ANDESITE of Silver "Peak region. OL ac 257 “BAIN, H. FostTmr, Reference to.. Page ANDERSON, ROBERT, Geology of southern AIG OF CUA et Mpa ialee wtPtl uk ea 107 410, 421, 422, "423, 424 —, , Sedimentary formations of the coal- ing district, California, paper by.. 708 APPALACHIAN coal areas, "Tonnage re- GUCHOMROL Ee eer lee ee 334 —— —, Extent of the reduction of the productive SMe Reuse ieee Seseee ee See fields! Absence of deposits in. — — —, Duration of —-——, Method of deposition of...... D — — region, Barren area of. . 333-334 ARCHEAN formations, Sketch plan of. — time, Reference to Carlivets. es adlaredne ARIZONA and western New Mexico, Re- connaissance along the Santa Fé PAMEOAGS TM le cette nena eel ARKANSAS Geological Survey, ; Reference to oucnal Report of State Geolo- LSU eran he, eee eee enn ere —, Reference to Geological Survey of.. ARIDITY, Erosive processes under condi- tions of —, Influence of ARLAT, ARNOLD, RALPH, Environment of the Tertiary faunas of the Pacific COBS Gita Acnotatel enahetal caene aioe —, Reference to 430, 579, 600 700 ee ey ARTIODACTY LS of the Aftonian fauna.. 350 SEE Gna re eLenencemtOnn ieee 632 ATLANTIC coast formations, iarte show- ing comparative columnar sections. 646 ATWOOD, WALLACE W., Geologic studies in the Alaska peninsula o fob arate otene 700 AVALANCHE action, Results from.. 412, 413 . 134, 348 400, 401, 407, 522 BAIRD, LVCLETEN COLON sii caclersnain cel. 571 BALTIMORE meeting, 1908, Register of Fellows and Fellows- elect in at- tendance at 705, 706 aja) /s/ 'a/le, a) 6 0\\0| 6-0 ‘eo e| 0) © @ Bartow, ALFRED E., Reference to.. 373, 383 — (and Frank D. Adams), Title of DAVESLAIDV Me vadoarseazeer sents Sane chek hoses 621 BARRELL, JOSEPH, Some distinctions be- tween marine terrestrial conglom- CLALCSRDVaencsuspe elem eyeteaieeieuca: 4 620 —, cited on influence of earth shrink- OL ENE ata cop anskan eras, cnokere has som ears 506-508 —, Reference to...... 430, 438, 506, aon, 679 BARRIERS, Description of land.... 440-442 Basat conglomerate of the Hsmeralda OMIM DONE dy cee cee ger sier ce ieee Wede se ocho 245 BASALT of Silver Peak quadrangle. 257—258 —-— Piper peak, Analysis by George SilelZerse uc ieraa henson ee —in Snake River fields, Lava solidified AUC Odom che arevsusrovevenare aha Gadel snenaitale lemons 21 BASSLER, , Reference to...... 430, 547 BASTIN, "EDSON S., Reference to......- 668 —. Chemical composition as a criterion in identifying metamorphosed sedi- MENS: CADSELACH) i seve ces casein seed 667 BAYLEY, , Reference to....... 666, 668 BECHE DE LA, , Reference to..... 66 BrEecHeER, C. H., Reference to..... 429, 536 (737) 738 Page BEEDE, J. W., Relationships of the Pennsylvanian and Permian faunas of Kansas and their correlation with similar faunas of the Urals.. 702 =5, Reference: to cc.) acikeeaeese aoe. woe 570 BELCHER, , Reference to0l...2% ;. .\- 583 BELGIUM, Reference to limestones of.. 164 BELL, ROBERT, Reference to........... 636 BELT-CAMBRIAN oolites, ‘‘Eggs’’ of the.. 168 BERKEY, CHARLES P., Reference to.... 436, 484, 523 BERRY, EDWARD W., Geologic relation of the cretaceous floras of Virginia and North Carolina (aberiaen: 655 —, Reference to 430, 586, 646, ore Brest) GaN, bererence sto: . | oceans 4 BEYER, S. W., Reference to... 134, 400 BABBINS, ARTHUR BARNEVELD, Refer- QING ORC OR teehee reese on iep ee iene sue 646, 672 —, Occurrence of the Magothy forma- tion on the Atlantic islands (ab- SIPEAGCE) yes, cia ie ay Ghee sneiswalenvushs poke. Syemewene 672 BIBLIOTHECA Nacional, Reference to... 1 BIBLIOGRAPHY of the geology, mineral- ogy, and paleontology of Brazil... 1—132 = SOhM (C.” Branner®. . © -cclesssetarcncienene 1-132 == Homer “Eo Mwllen) 2. seas wicws eecsaeusie 618 BILLINGS, s VCLETENCEMUO!. yo eis eels 536 BLAKE, WILLIAM PHIPPS, elected Fel- TOW: eater oy exten ores remain one 616 —, Fossil fishes collected by.......... 244 BLACK sea, Limestone deposits in..... 105 BLACKWELDER, ELIOT, elected Fellow.. 616 BOESE, , cited on Cardenas faunas. 588 =, PMCREECM COCO a cccniegeconeiet o te teel cosh ore are 588 BOHEMIAN rivers, Hanamann’s investi- PATTON Ole ae sees ee wie ee eee ab Sane shor et sie 155 BooNE Chert series, Saint Joe marble BORDEN, , Reference to on New Providence shale 5 BOULDER deposits in mid-carboniferous marine shells, Ice-borne.......... 701 BRACHIOPODA, The Richmond group of. BRAINERD and SEELY, Reference to. 523, 526 BRANNER, JOHN C., Bibliography of.. 1-132 —, Comparison of effects of earth- Qwakes; PApeE Wis cies see easton T07 —, Geology of the region of diamonds and carbonados of Brazil......... 708 == Reference to 2. .2)2'< owe a fee 707, 708 BrAVAIS, A., Reference to.... 370, 373, 3838, 385, 386, 388, 389 BRAZIL, Bibliography of the geology, mineralogy, and paleontology of. 3-132 == HOSSiT MISHES “ErOME ccc. ne ee sus wo edens T07 —, Geology of the region of diamonds and: (CarbonadoOsmims ocecw. viele sors ss 708 —, Résumé of the geology of.......... 708 BRECCIA, Diabase in contact with the.. 209 Breccias of the Esmeralda formation, Tertiary detrital slope....... —246 BREGER, , References tOee ws es sacs 430 BrRIGHAM, A. P., Reference to.. 633, 624, 670 BrocK, REGINALD WALTER, Reference to. 659 Brooks, A. H., Reference to.. 430, 551, 700 Brown, CHARLES WILSON, elected Fel- TOW? Fac 5 tidig tae oes one ee TR eer e 617 BROWN, , IRELETENICE HtOR ee ot oe ccs. 594 BULEETIN, JDistribution Ofer eee. a 610 BURCKHARDT, , Reference to...... 581 BURNING Springs volcano, West Vir- F241 OU 2 a an PERE E SR EA 5." cca aae 334 BURLINGTON fauna, Reference to Upper anid! ower 220.2 ae eee ee 326 BusuH, Lucy PECK, Reference Ome 430 BuTTON Mould knob, Fauna of........ 325 CADWELL, CHARLES A., Reference to... 630 CALCAREOUS augen-schist, Figures of... 231 = fossils, Wirst = 2.4 shine eee eee 153-168 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page CALCIUM carbonate, Formation of crys- GALS! OL Gs) 5, 5 se eieiens oe yes Se ee 168 —\—, Precipitation “of )25.. eee 156 — in limestones, Average ratio of mag- MESIUM! LO -/.0ss. oe soe 163-165 . — sulphate, Present amount dissolved in ocean of... ... iuisos eee 166 — supply to ocean, Maximum rate of.. 157 —-—, Variations in... .....hoeeeeee 162 CALHOUN county, Illinois, fauna, Chou- teau Same-as.... 0.1252 eee 322 CALIFORNIA coaling district, Sedimen- tary formations of the. aa- eee 708 — coast ranges, Structure of central portion Of 2. os.0cs66heeeee 708 —, Minerals from the coast ranges of.. 707 —, Stratigraphy Of oss Se an Cee 708 CALVIN, SAMUEL, An Aftonian mam- malian fauna ....-...000 - 699 —, Paper on Aftonian mammalian FAUNA |. ik. 6 4 coe eee 341-356 —, Presidential address of....... 133-152 —, Reference to........... 342, 400, 402, 408, 609, 625, 638, 661 CAMBRIAN fossils from Silver Peak quadrangle >. nos eee eee 226, 239 ——and pre-Cambrian limestones, Origin’ Of .s.ln. 8S ERE eee 155-170 CAMEL of the Aftonian fauna.:...... 350 CAMPBELL, M. R., Reference to. . 334, 624 CANADA Geological Survey, Reference TO Saw le ces Se 509 CANU, , Reference to. ... 4381, 444 CARBONADOS and diamonds of Brazil, - Geology of. . ... .s4.t+ ase 708 CARDENAS faunas, Boese cited on. 588 CARNEY, FRANK, elected Fellow. 617 —. . Glacial erosion on Kelleys “{sland, Ohio .....<..:.+2. ree —, Reference to .......622.. 628, 633, 670 CARPENTER, , Reference to....... 476 CASE, , Reference to. ate 570, 571 CERATOPS beds, Stanton and ‘Knowlton’ eited: (On) f5.3.05.55 se eee 595, 597 CHAMBERLIN, T. C., “Aftonian’? name given, by oc. .see see eee 136 —, Diastrophism as the ultimate basis of- correlation ... 2). .eh sen eee —, Reference to..:. 134, 135, 165, 341) 342 399, 400, 434, 447, 464, 473, 505, 506, 507, 509, 513, 603, 605, 635, 638, 641, 642, 559 CHALK formations, Northeast Texas. 645 “CHALLENGER”’ chemists, cae of. 156 CHAMBERS, ROBERT, Reference to. . ATT CHARLES, JOHN H., Reference to...... 348 CHAUTAUQUA, Illinois, Thickness. of Fern Glen. beds “ini... ene 268 CHEMUNG of Maryland, Recurrence of the tropidoleptus fauna in the. 680 CHLOROPAL, Analysis of specimen corre- sponding tO. 02. okie eee 263 —, Silver Peak region, Deposit of. 262-263 CHOUTEAU and Burlington, Relation of Fern Glen faunas to. 321-323 CINCINNATI, The Paleozoic ‘region of... 445 — Society of Natural History, Refer- ence tO 254s. .6.s56 eee 530 CLARKE, F. W., Reference to his “Data of -Geochemistry” |°> 252 eae 155 CLARKE, JOHN M., elected Second Vice- President ° 2.650 ssc eee 616 —, Reference to.......... 2, 430, 436, 461, 526, 542, 543, 544, 545, 660, 681, 688, 689, 690, 691, 693, 696, 698 — — — compilation. of river analyses IV | sd wisi ain ee Waren St oie eee 160 —, Record of remarks on age of Gaspé formation 96-697 —, Vote of thanks proposed to the Johns Hopkins University =< the citizens of Baltimore by.. ecw OOH © ©. 6° @: © ee, 0f oe (0) wa, wpe alle INDEX TO VOLUME 20 739 Page CLARK, W. B., Coast plain formations between Massachusetts and North Carolina (abstract) 646-654 —, elected Treasurer 6 —, Reference to........ 600, 609, 635, 655, 659, 660, 671, 672, 688, 698 —, Report of Treasurer.......... 612-614 —-, Response to vote of thanks by..... ; o ‘and M. W. Twitchell, Geological distribution of the Mesozoic and Cenozoic Wchinodermata of the United States (abstract)..... 686-688 CLAYTON valley, Granite rocks of..... 250 CLAYTON, J. E., cited on diorite dikes.. 238 —, Fossil fishes of “Esmeralda forma- LOM COME CEEML DYscin cua cies ele: celelats 244 CLAYPOLE, HE. W., Reference to. 525 CLELAND, H. F., Some features “of the Wisconsin middle Devonic........ 701 (‘LEMENTS, , Reference to........ 662 CLIMATE of Aftonian interval........ 343 COAL-BEARING rocks, New Mexico, Paper by Willis Thomas Lee on. 357- 368, 621 — bed, Annual production from....... 335 — beds, Acreage of West Virginia..... 336 ———— Duration of Ohio...........06.. 336 Taare Pennsylvania, Area remaining ne Naa sGults of Appalachian field, Reason ROM SENCCT Oleic ok ess eee oe wee. e 335 — field of New Mexico, Unconformity in the so-called Laramie of the PERerin@ Mle ee oe ee acct rie tas snatie is) 357-367 —.—, The barren zone of the northern VANPHITENIEVOMM AN orc. gee eialie tes Goce tale ie e's 333 — fields of the northern Appalachian, AON OL i isiae.toc cies so 8 wees 335-336 — formations of the Raton field, Plate Showane) Sections Of ©. ...c0.c8 055 362 — in northern Appalachian coal field, INORG SOMOL edhe 2 ols goose ls euene 333-339 —of Appalachian field, Method of dep- COS DLONIMEO LR UAT: ccts) orkls 2-8 5 late eceue etait oe 335 — saved and utilized in Pittsburg vein. 336 Coknb from beehive ovens, Superiority Oil - oho. cronolON ROR DEORE CREE ToD eee manera ¢ Coast plain formations, Massachusetts TOMINOREM CATOlInas 2). sie. os ss ses 646 COLEMAN, A. P., Lake Ojibwa, last of the great glacial lakes (abstract). 639 ==, | RGMAHEANCS) IRs alo eee eee eee 134, 670 CoLLInR, WeIVGREEEMNCE Os] astae eis.» 582 COMANCHIC formations, Table of Texas. 583 CONGLOMERATE basal formations of the post-Laramie coal measures, Plate INO MONUN OA es, airs hiss. ais ocietvoniods ce, suena) ailetia,\e 363 — beds of Esmeralda formation... 246 — post-Laramie formations, Descrip- Hal COU TMMNO Lee ee Wee techie) cic Ietie falne Marco vammealye nang hee as : CONGLOMERATES, Marine and terrestrial, paper by Joseph Barrell (abstract) 620 —, Distinction between marine and {WOIPECR IE” sg GR A alata we ero ame Br a 620 CONNECTICUT valley, Triassic sandstone CIM eRe Loi ails. cue leva les «tape bie bate when CONRAD, , Reference to.. 682, 684 CONSERVATION, Committee on......... 633 =—Tor resources, Need of.......04 338-339 CoNTACT metamorphism of Silver Peak CGUAGEANGIS: oie ee ho sss sie s 261-265 CONTINENTAL region, Subdivision of in- REIEIGIE Avec on Gach Gen eAR one CRE ene 47, 448 ISCAS DGG: Olin s so. ais ciece Mawauelenscelacs 438 ——of North America, Classification Oe ee ar era souereber aaa ian 480-481 ——, or negative continental elements. : 447-464 Corr, E. D., Reference to..... 348, 356, Bas CORDILLERA, eg Sh OL the nes sisi CORDILLERAN Section, aiete he papers presented before the. 707-710 Page Costa SENA, JOAQUIM CANDIDO Da, elected: Melllowsaie cies sere ee cece 617 COTTEAU, tu veherenmce tO. cic: sales 584 CoOUNCI Report Glass. veer cae ee ee O09 CRAGIN, wo eference tos we. ay sche: 582 CRETACEOUS floras of Virginia and North Carolina, Geologie relations (OE, PRR CLER Stee nS ne ura eth Sh hae misao ale 655 — formations, Table of Massachusetts tOmeNOLtH JUBNAEO- ChAISMOIMN Olen nano dic a ub Geol ou, 380 —, Plates 31 and 32, showing classes of 398 iE LeSehii Classifications oleae eee 370 —, Proposed classification of..... 370-397 —, Relative rank of classes and systems CO) Ry fo RES ge tal tr Rn 383-385 —, Review of the development of the thirty-two groups of......... 385-394 —, Summary of proposed classification of 3897-398 == MATIEM OL SAROUINS Oita desde hic dade su —'__ larger divisions oO hepess eee —, Theorems for basis of classification OL pe orsy ohtn eRe ae ce 372-373 Pay DeSTOn SS ymMMe hry S06 ase cas cian CULLIS, C. G., cited ‘on deposits made oy VNPROCUECHAL CORN. 6S odin a eo bene CUMINGS, HpGAR R., Reference to..... , Reference to..... 561, 570 CURRIE, P., Reference to. 370, 385, 386, 391 CURRENTS as fauna distributors... 442—445 CurTIS, G. S., Reference to.. 418, 419, 420 CUSHING, H. P., elected Librarian. 616 ——, Librarian, List of societies, institu- tions, and others receiving the Bul- letinials donations 205. senal. 5 711-720 —, Reference to ONO Op CUO CANT DONC ONCMCECHChIC CauO) CusCiAcle Par) CUMMINS, DANA, EDWARD SALISBURY, elected Fel- ONV rc one atin asd ee tar etter oes oes DANA, JAMES D., cited on Paleozoic DoOSitivie elements) oes aac. 464, 465, 469, 471, 472 —, cited on strand-line displacements... —,Reference to works of.... 384, 431, 432, 433, 437, 447, 448, 450, 451, 453, 454, 456, 457, 460, 462, 464, 467, 470, 474, 475, 484, 488, 501, 505, 509 DaLL, W. H., Conditions governing the evolution and distribution of Ter- CLAY MRA ILIMA See cs ciroee susnculogsneceunt econ crenens —, Reference to..... 430, 444, 445, 463, 597 DALY, REGINALD A., First calcareous fos- sils and the evolution of the lime- SOMES er suse eee emer eee ass 153-168, 620 Se VGH OEGHICE ailiOis ts) aces suey suede snacks deen sates 572 DANGEROUS mining zones, Locations of. 337 DaRTON, N. H., Reconnaissance in Ari- ‘zona and western New Mexico along the Santa Fé railroad...... ere ee © 740 Page DarRTON, N. H., Reference to...... 567, 672 — — — Catalog and index of..... 430 —, Report of Photograph Committee Dy. 703 DAWSON, GEORGE M., cited on Shuswap series of Rocky mountains in Can- BOS a ee Sa Ss ibe 134, 468, 469, 551, 572, 577, 586 DAVENPORT Academy of Sciences, Refer- ENCE, CO) ss) 5 vadeeresep ekeretens oremeus rotele a are sic DEEP mining, Danger of......... 337-338 DERBY, ORVILLE A., Résumé of the geol- ogy, Of Brazile paper Dyess ee. —=, Reference) tO aie atte mcticicte soe sue ote DesERT detritus of the Silver Peak quadrangle 247-248 — ranges, Relations of present profiles and geologic structure in the..... varnish of Silver Peak quadrangle... DETRITAL fans of Silver Peak region.. Drvonic formations, Table of........ 541 eee eee eee ee eo eee DIABASE, Breccia in contact with the.. 209 == IDISSAIODUAION, Ole SoocoboooeGaas 220-222 —formations, Sketch plan of:......... 199 —, Information about source of....... 217 — in Lake Nipigon basin, Original vol- AITO MIOLs ess rav cnasenete Votoms coche ence eee 210 — sheets, Columnar structure of...... 215 == == in AON ORIONIG, INEVERONISS 6 osc 555506 206 = = = \Wouanosn WAVlIy saccads6os0c 205 SS ROOK NGA 55 65c0d050000c 204 SPV MES) 2Ol 7 cia ceod ale esis eke oer Peilat — -—, Unconformities of three types of. 211 DIAMONDS and ecarbonados of Brazil, Geology. Of vot ide wk eaten le wen 708 DIASTROPHISM, Ultimate basis of corre- MALO es fie el cee rete olans comer mueteieaens DILLER, J. S., Reference to... 540, 571, 572, 586, 593, 612 DARI} ROO (COR NNDUIENPS 655 coho oo Go OOor 252 DINNER of Society, Annual ck ae choveke eters 659 DIiINOSAURSSE Species Oleeeneieiere cies 438 DroritEe dikes, Authorities concerning... 237 —-— (greenstone), Analyses by George Steisers aco ena oeulke Gee eee eee reik —-—, Composition of ........... 237-238 —-—,, Influence on ore veins by....... 238 MY — - of the Silver Peak quadrangle. 237-238 Dr JLAPPARENT’S Traité, Reference CO an eee cones 4338, 435, 436, 605 DOLOMITES, Origin of early Paleozoic anda pre-Campriany sy cieereeeiee 163 DOWLING, MCECLEN CE) tO: siecle seis 430 —-— — general index of........-..... 431 DRAINAGE evolution in central New YO Oe RSet eee AU 2 airs eR Ct ape 668 — problems, HPastern North America ATHENA See Onoh Gert Coatacoro ey ome rein 668 IDO, OM dN. sono 5550nq05ec 136 ==) AMDECMTAN at Scien ie oes a eetis Vere one o Gre ondte cs 135 S— , JOTSC YAM erie ees rete esterase ere ees 135 —of Iowa, Pre-Kansan or _ sub-Af- FONTAN TS. 535s eae ete esas 136 Drirts, Information given from Iowan. 135 —, lowan pre-Kansan or sub-Aftonian. 135 DupBois, E., Reference to calcium ecar- bonate carried by rivers.......... 156 —= => =—‘Solutes os hn Deen oases 166 IDWwa To IDL WNL IRGARINOCD Wasco ccacac 488 DURAND, W. F., Proposed form of seis- mograph, paper by (abstract). 708-710 IARTHQUAKE and Volcano Observations, Report of Committee one=- oso .. 359 TOUS ES Comparison of effects OE HE Satins Bi Her ke Te a EFAaRtH shrinkage, Joseph Barrell cited on influence of 506-508 © © se) © 0 © « «0 © « BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA ECHINODERMATA of the United States, Geological distribution of the Mesozoic and Cenozoic........... 686 HDENTATA, Aftonian’ 25 25-0 eee 353 Eprtor, Report of .......5.5)5neee 614 ELEPHANTS of the Aftonian fauna. 351—352 HLS, Re Ws References tou seeeeeeeee 430 EMERSON, B. ae Reference to. 625, 659, 668 ERAS and systems, Geikie cited on no- menclature of ........2.0eeee 515 EROSION intervals in the Tertiary of North Carolina and Virginia..... 673 ESCHWEGE, L. W., VON, Reference to.. 2, ESMERALDA formation ........... 243-247 — -—~, Areal distribution of beds of. 244—245 —-—, Coal deposits of... 52-4. 244 —-—, Conglomerate beds of.......... 246 —-—, Neocene river gravels of.... 246—247 -——, Pleistocene conglomerates of.... 248 — —, Reference to 2 e ©) (ee @) 0.50) ©) i wi uel mie — —, Reference to fossil fish of...... 244 — — — — — plants of... 0.2. eee ee —-—, Tertiary detrital-breccias of. 245-246 ETHERIDGE, ROBERT, Reference to..... 431 Ewine, A. L., Reference to........... 155 FaIRCHILD, H. L., Drainage evolution in central New York (abstract)... 668 —y; Glacial waters west and south of the Adirondacks (abstract)....... 633 —, Multiple glaciation in New York... 632 —, Correlation of the Hudsonian and the Ontarian glacier lobes..... ~.. 634 —, Pleistocene features in northern News Vorke-nivs cvereuete aed dd Sveteweeneeenete 635 —, Reference: t0.:....)... = eee 634, 668, 670 FARIBAULT, , Reference-to.2- ae 43 Fauna, Aftonian mammalian..... 341-356 — distributors, Currents as...... 4492-445 —— Hirst interglacial’ 2. eee eee 135 —, New Providence shale............ 320 —'of Button Mould knob, Reference to. 325 —- Calhoun county, Illinois........ aon —— the Chemung in Maryland, Recur- rence of the Tropidoleptus....... 680 — —-— Hern Glen formation... 265-327 —, ‘Sheridan formation” and Aftonian. 354 FAUNAS, Conditions governing the evo- lution and distribution of Ter- HIALY «ce 0 oe 3 8 6 See 704 —, Evolution of early Paleozoic. 703 —'of North America, Middle and Upper Devonian and Mississippian...... 703 — —the Pacific coast, Environment of Tertiary — .s:6 .'s\s.s 6 ssnh- Eee eee 704 —, Pennsylvanian and Permian of Kan- sas Relationships and their corre- lation with similar of the Urals... 702 —, Succession and distribution of later Mesozoic invertebrates .........-. 704 FAULT, California earthquake ........ 187 —, Figure of displacement at a....... 172 —, Parallel displacements at a.. 178-183 —'walls of Silver Peak range (figures 1 and 2, plate 9). ...<. 2s 264 FAULTS, A system of projection for de- termining 2. 2.5.) eee 173-177 —, Classification of ..2.. -22eeeeoee a D7¢7/ —, Difficulties in determining move- ments of sc.cacst kt es eee 193-194 —, Folded or contorted strata of.. 186—187 —, Geometry Of «292.55. eo oe 171-195 —, Nomenclature of ............ 172-173 —, ‘Normal’ and “‘reversed”........ J. 172 —, Parallel developments of...... 185-186 —, Possible displacements of...... - ee —, Rotation with translation of. 189-193 —, Rotatory displacements of..... 187-189 FAVOSITES from the Thayer beds. ..c08 138 INDEX TO VOLUME 20 Page FEDEROW, ———, Reference to..... 370, 374, 376, 385, 386, 392 FELLOWS deceased, List of....... 735-136 MOC tLOM: OL). book Sa ob we ee 616-617 FELLOWS-ELECT, List of.......... 733-734 1 LUAISILE: «COTE ces sea ae nee un lee cL 705-706 FERN GLEN beds, Chautauqua, Illinois. 268 —-—of Saint Genevieve county, Mis- SONU clout ame Fe es aicousve ee cusc ma iome =a seule 1hiI@ks, Illinois — fauna, Plates and description of. 327-382 ——, Table comparing Saint Joe wit 324 oy ROMS ELOMMG 1s. os fel chs ee bie wisi alin es 65-327 — —, Description of species...... 269-321 —-—, Other fauna compared with. 321-827 MMT CKMESS Of. ics us Ges oe eels es 266 formations in deep-well sections.... 268 FINCH, woReTereNCe. LOkt «a eee ek 400 FISHER, CASSIUS ASA, elected Fellow.. EMSS BRazil fOSSH 6s. s Ge ee be es — in different periods, Development of. 166 617 707 FISH LAKE valley, Drainage in....... PEPAT HinRKchae PAV IReELEreMee TO. 6.6.6 5.22.6. %% 164 FLETCHER, INVERTS MCE UO eee oe 430 EFLETT, + 1D ese Reference WOcnnic ILoRA, Raton mesa region........... FLorRAS, Succession and range of Ter- idamyaeanad: Mesozoic: . ..5....--..- 704 ONO Pe ALCOZOIC. 6c... sees tee ie 703 FLows, Source and nature of...... 217 FomrRSsSTE, AuGusT F., Brachiopoda of the Richmond group, orally pre- Semtedm bya (abStraet)'. io... «eck = 69 —, Reference to 537, 623, 699 FONTAINE, W. M., Reference to 567, 656, 657 jw) ol ie! (ei (6) @) [¢) 0, “619 0) « HOSS ISMESS STAI ois 55 ls eles el se ee TOT — localities of Fern Glen formation... 269 Fossius, Aftonian gravels containing ATAU ATN ceileles es cte aie ans 401, 402 —-proboscidean .............. 352-353 ——, Cambrian or Algonkian........... 239 = wxacth time indicated, by.........- 439 —, First calcareous, and evolution of the limestone, paper by Reginald AG IDEN eaten Ri i Hy Be 153-170, 620 —from the Aftonian of Iowa.... 137-139 —of Aftonian fauna, Figures of.. 349-353 Tver meak. GQuildrangle:. .- 1.14.4 220 —-— the Fern Glen formation.... 265-328 FrpeAR, W. F., Governor of Hawaiian ISIAINGI, “LUG eye Oley is oie a ecicncioeed o 660 FRECH, 7 Reference: to... =... 434, 468 FRESNEL, 4 JRGIEIEAKK 1G oboe 0 6 ce 380 Fouquh, : pererente LG Aeraea ra B6e He Helene SeMitn Witte: OLn c sic. as 1s —337 a i 339-340 —, Remedy for waste of.......... FuLuLER, Homer T., Bibliography of... 618 —, Memoir of, by Edmund Otis Hovey. 617-618 —, Reference to death of............. 610 FULLER, Myron L., cited on veins or GUKESI Of. (QUATCZ fos sic wielevere om ee 237 FUNAFUTI atoll, Reference to......... 163 GADOLIN, ALHXIS, Reference to... 370, 385, 386, 390, 391, 394 GARDNER, Miss J. A., Reference to..... 646 CAS ViaASter Of om acuralinvccs a6 6 oon 336-337 GASen sandstone, Age of.....5...0.2. 688 GEHLER, Reference! tOnca ste aes 386 GEIKIE, ARCHIBALD, Reference to...... Bid GEIKIE, ~ Reference tOk/ sce eee 399 GEIKIB, JAMES, Reference to......... 342 GEOGRAPHIC Magazine, Reference to Na- LOMA at Wasa us sun oo ete eve te aie rare ce 421 GEOLOGIC Nomenclature, Names of Com- LOGEC ROMS ates arte ey a ete 620 GEOLOGICAL Survey, Reference to Iowa. 399, 400, 401, 407 —, Reference to United States........ 446 Page GnHOLOGY, Bibliography of Brazil.... 1-193 —of Silver Peak quadrangle, Ne- Wal at Os eri ee ee Te eae amt s 224-264 —, Stratigraphic, areal, and paleonto- OBC Se shy ROTOR pe oe 672 GuoMmmnnYe of faults... 558s). 171-195 GuORGE, R. D., Reference to...) ...).) 509 GIDLEY, J. W., Reference to...... 345-350 ONC ON OS Oe OBO Gog GoGo 620, 631, 632, 633, 637, 638, 641, 659 GirmyniG. Es cited von Pottsville series MUON su snat fence sesh nec 559-561 —, Physical and faunal changes of Pennsylvanian and Permian in North America = SReterenceu ton | ttndiel RAT REA eee 703 546, 547, 550, 563, 565, 566, 567, 568, 573, 574, 575 GLACIAL deposit, Kansan the oldest Pe — drift sheets, Criteria for age of. fe @a3 — epochs ITE PLOW ere ay ie eis 135 a aie North) America: Number of... 134 — erosion, Kelleys island, Ohio... om tkesOribwanlastotvenent).1.. 1. a6 — phenomena in Iowa, Views of.. 136-137 — —, Southeastern Wisconsin eed —_~ waters, by H. L. Fairchi 3 GLEN PARK station, Eocuos eee) Bre — section, Fern 265-266 GLACIER lobes, Correlation of the Hud: sonilan and the Ontarian 6 Poy KE. L., Molars of horse found OOO 60 6 6 OD O46 ONG) O88. 10 BGI Sis. G's GNEISSES, Nipigon basin... aa : ; j ae S00 eee Peak quadrangle, Composi- —, Primary origin of the folia ed struc. es ture of the Laurentian, Soa Adams and Alfred E. Barlow. 621 GOETHALS, Cou. GEORGE W., chairman i and chief engineer Isthmian Canal Commission, Metter oie 660 GONDWANA, Continent of). 0): om oe 432 GOODWIN-AUSTIN R N-£ n eference to Con Chix wEInNRTA Retoreoaa (i ee 431 a i eferen GORDON,” ; Pao Chalk formations of (abstract). GOULD, CHARLES N Present k i ‘ n of the Oklahoma red beds. cee GRABAU, AMADHUS W., Physical and a es en of North America e late Ordovicic, i Devonic time ues —, Reference to cpelel folks Teli sitwasneeso ins tcten am 703 436, 467, 537, 634, Sete p 670, 689, 699, 701 =, Tertiary drainage problems of east- ern North America (abstract).... 668 GRANTEES Meriiatitie@! o.!.4 35.8... 8 202 Sem cibe: (PANASKite): oases ome: 232-235 GRANITE-GNEISSES, Traps overlain by.. 206 GRANITES, Lone mountain ......... ae 250 —— (quartz-monzonites) of South Caro- ‘ linayePe tology, Of. ses cee 668 GRANITIC quartz-veins of the Silver Bedi quadranviles so seeeae 235-2357 Se PUSS AO) Ciena ce ama BAL ely 236 GRANULAR dike rocks of Silver Peak PRS UIT SONY Me cates epetar tintin bee nae 252-253 — igneous rocks of Silver Peak range.. 249-252 GRAVEL pits, Figures of Cox and Pey- GOI Gene ea alae en ea ok ee 343 GRAVELS containing mammalian fossils, JAIRO GHG OV A eee met a eerie Ae pe nes 401, 402 —in western Iowa, Aftonian sands Ei a\(0 UNMan en case pe ener: oS RE cae nO, 399-408 TOE suney Silver: bea kmerecion-n: ancien 248 742 Page GRAVELS, Reference to Kansan and TOWat: . eesec5 SS S oie Sele epeatiee en ee ehete —, Western Iowa GRASTY, J. S., and Edward B. Mathews, Character and structural relations of the limestones of the Piedmont in Maryland and Virginia......... GREENSTONE, Diorite dikes same as... GREGORY, H. H., Reference to.... 584, 590, 600, 660 GrorTH, ———, Reference to....... 372, 317, 884, 387, 397 Cue, KF. P., Nantucket shorelines, fe. eee me oe Oe ae eile aue inte ev 670 —, Nantucket shorelines, IV (abstract). 670 —=, Reference tO) xc. cites out 659, 671, 703 GURLEY, » Reference. tO... 2. ss s8 a 528 HAGUE, ARNOLD, Reference to....... -. 565 HALL, C. W., Reference to....... 581, 682, 683, 684, 691 HALL, JAMES, Reference to....... 429, 489 542, 543, 554, 560 HANAMANN, J., Investigation ‘of Bohe- IMIS LUVELS DY ues shece che cite are iay5} HANDLIRSCH, , Reference to....... 567 HARKER, . Meference TOk. ses 6 = om 662 HARRIS, GILBERT, Reference to.... 463, 597 HARTZELL, J. CULVER, An old beach ter- racewin Nevada. paper ibys. e es 707 — A. remarkable Clay.c. 25. 254.6406 707 —, Reconnaissance about the big sur- region of the Santa Lucia moun- PATTI five ede cirat haudilaceiatrcud ave a auaveucveMeneaees 708 HATCHER, JOHN B., Reference to..... 592, 94, 596 HAWAIIAN islands, Letter of Governor Hirearrs: Titi chistes chert 2 cee mee ome bec terete 660 HAWES, Dr. GrorGE W., Reference to.. 619 EAS (Co Wie SRieferenicemtOl. oc ce see 660 HAYFORD, , cited on isostatic com- DEMGATOME 05 coors cee cere cae 502, 503 HEER, , Reference to.... 431, 436, 471 HerRSHEY, O. H., Term ‘‘Sierran period” INtGOdUCed | Dye eae ce eee eee 248 WESSEL, J. F. C., Law of rationality of parameters developed I Oh Goes hee: —, Reference to. 870. 371, 380, 385, 386. 387, 388, 390, ee 397 HILLEBRAND: W. E, Reference to. 228 ISTP aby lets a4 DES Reference Om ene 983 ELIHU Sees (62s RGreren Ceo dOm asa cio ate risus. HINDE, H RGLOREH COM LOM ee acre: 134 Hirencock, ¢: H., Reference to...... 437 == Ihe) Voleane Wilatears aie ss sie eae 632 Hrrencock, H., Reference to......... 537 Hopss, W. H., Reference to.. 620, 625, 661 Houuick, ARTHUR, Reference to. 672 HOLMES, WILLIAM HENRY, Reference COG Noia aha eens elo te teed Se eRe tee tee Sue ers HOPKINS. VIMO s NReterencestomes. 32.) Gol HouzInGcer. J. W., Reference to... 400 Horses, Aftonian fossils of.......... 138 === SAE LOMMAMN he eoo see re eee oe eeeas 344-350 —, Comparative table of teeth of ATTONIAN és) 2S ao eee 345-346 —— Migures) Of > teeth Ole. a1 ier 343, 344 Hovey, EDMUND OTIS, ATE re ig ais a eae ten eho leas oe 616 —, Memoir and bibliography of Homer DS Ever yi sec eee eee 617-618 -—, Mount Pelé and the Soufri@re...... 632 —, Reference to .... 419, 421, 424, 659, 660 —’ Report Of S@cretary.c.c ces ene 609-612 ——. "Titlerok papers) by f-seeeee eee 409, 417 —,Striations, U-shaped valleys, and hanging valleys produced by other than 2lacial action tases cies ee oie 670 HOowE, , References to@.. 2.cn1s- 3 - BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Pa HULL, , Reference to. ........ aoa) tee HUMBOLDT bay, Diabase on.......... 206 HIURONIAN and _ pre-Huronian lands, Composition [Of 2 aacche 4c 56 — -— post-Huronian, Areas of land and S64, (Of 0.353. ae ee ee 157 HUSSAK, E., cited on veins or dikes of QUATEZ ese a nee os eee Zo —, Reference to... 3.5 1 ose ee 2 Hux ny, TT. H., Reference tel... eee 666 Hyps, , Reference tO. <= ee eee 562 IDDINGS, J. P., Reference to..o) oe 607 IGNEOUS rock, Keweenawan sediments in contact with ...- >. oeo. ee OT — rocks, Granite and syenite series of. 249 —=--, Granular... eae eee eee 249-252 LLLINOISAN Grikt 72.500 141-143 —-=—, Kewatin origin of... 502 141 INDIANA, Reference to geological sur- VEY Of 3. ois 2 c.u. os ne See 325 InGaLi, H. D., Reference to.) ae see 200 INTERNATIONAL Geological Congress Reference. 10)... 55 o aes eee ee HD INTERGLACIAL interval, First Iowa.... 135 —w—, The Aftonian a real........... 139 INTRUSIONS versus surface flows...... 209 INVERTEBRATE faunas, Succession and distribution of later Mesozoic..... 704 INVILLIERS, HE. V. D’, appointed on Com- mittee, of Conservation. oo.0 oes 633 lows, Aftonian interval in. s...) soe 136 —-—, sands and gravels in western... 399—408 —, Contributors to Pleistocene knowl- edge IM 2.8 ss ok ae Cee 134 —, Drift sheets. im. .%..:.>. some eee 134 —, Drifts in Harrison and Monona counties: .... 6 5.0% 2 5 6s eee IowAN drift, Extent and age of... 1438-148 characteristics, and drainage OL <5 4s. ,60eeeeee 146-148 Iowa, First and second Glacial epochs ik... Pi cneee ok ce eee Use ——. Wossils and) faunaiok-.) eee 137-139 — Geological Survey, Reference to staff OF. ies s ASS Se tee 399 —, Interslacial interval ingese eee 135 —, Location of, with reference to gla- cial. jqepochs. <2): 19. see eee 134-145 —, Mollusks and mammals in Aftonian STAVEIS: OF auc. sissies os ines ee —= Peat beds of @% s30-— eee 399, 400 —, Pleistocene problem in........ 133-152 —, Pre-Kansan or sub-Aftonian drifts Of one So oe eee 135, 136 — ores, Maryland 2.01 - eee 671 IRVINE, R., Reference to: .. 5.00.0 00ee 154 ISOSTATIC ‘compensation, Hayford cited ON | bss ons ee RE ee oe 02, 503 ISTHMIAN Canal Commission, Letter of Col. G. Goethals, of 3... : >) eee 660 JAGGER, T. A., JR., cited on California earthquake fault. i... ee eee 187 —, Report of Committee on Harthquake and Volcanic Observations, by chairman: 2.0045 25 ee ae 660 JAMAICA, Letter of Secretary John- stone, Of 2.6.2 4k oe eee 660° JAPAN, Geology of southern.....:..5: 707 JERSEYAN drift, Reference to......... 135 JOHANNSEN, ALBERT, elected Fellow.... 617 JOHNS HopkINS University, Vote of thanks to citizens of Baltimore and authorities, .of ..<\5. «cuss eee 704 JOHNSTONE, WILLIAM, colonial secre- tary of Jamaica, Letter of........ 660 INDEX TO VOLUME 20 JOLY, J., Scientific transactions by.... 157 JORDAN, DAVID STARR, Some fossil fishes OM PESTA ZINC Wcyneeterecsietsrcncier aie ow eilgnees 707 JUDD, J: W., Reference to............ 662 JUKES-BROWN, Reference to........... 433 IKANSAN and pre-Kansan, Age of dis- tributed gravels between......... 138 — — — drifts, Relative age of........ 140 — deposits, Relationships of ......... 139 —— drift in Tama county, lowa........ 136 IXANSAS, Pennsylvanian and Permian HN UIA ASE O lent smersy arene, sce) eller cia ile talane, o oce 02 KARPINSKY, , Reference to....... 434 Kay, GEO. FREDERICK, elected Fellow.. 617 KEELE, MUIVELEEEMICE Om acre enous alee 430 KEEP, JOSIAH, Pyrite mines of Leona HMM OMe eee ass Guz ee Res uoleldes cheee 5. weoresd 07 KEILHACK, KONRAD, Reference to der NGM ICT O Laven cine cos si orc ahoreeeseg eines 176 KEITH, ARTHUR, Committee on Geologic Nomenclature, reported through... 620 KELLEYS island, Plates showing glacial phenomena on....... 640, 641, 642, 644 Kcenre, J. H., Reference to............ 662 KENTUCKY coal fields, Map showing con- nection between eastern and west- CUTIE Ieee eos s Tice ie sas bal elgnrw abvepe 621 KEWATIN schists, Traps overlain by.... 206 KEWEENAWAN formations, Sketch plan WHEL, 5 Q)ceg nea kee er mea 207 KEYES, CHARLES R., Reference to. . —., Title of two papers by............ KING, CLARENCE, Reference to.... 248, 453, 454, 469, 566 430, 539, 540, KINDLE, , Reference to... 543, 546, 551, 572 . KIMMSWICK Fern Glen formation, AM MUA CITC (0) ee a ee 266-267 —, Missouri, Fern Glen formation fos- SIS “WOO... 6 oS aeen e ee RONG Lene Re Ree ee 266 KINDERHOOK faunal studies, I, Refer- |, SNES WOR Re ee eee eer 267 — — —, IV, Reference to............. 265 Knapp, M. A., Faults in Silver Peak range first recognized by......... 264 —, Reference to coal deposits.......... 244 eNEcrm ©, E., Reference to........... 224 KNOBSTONE group, The so-called....... 325 KNOWLTON, F. H., cited on plant forms {identified from the Raton coal field, ING wae Ml@XHCOl Es coc giccistlerets «6. < 365-367 == heference tO......... 430, 594, 595, 596 — — — fossil plants, ““Esmeralda for- mation” —, Succession and range of Mesozoic and Tertiary floras, paper. by. ae 704 Kwnort, W. T., Reference to....... 21-623 KOKEN, A IVELeRENICE: stOe cus eels ener. 434 MpaAus; ch. El, Reference to. . <0. acts 661 Krt}MMEL, , Reference to..... 455, 476 LACOH, WeNVGLERENCE) tO'e sc) s ais oie a ce 567 Lacroix, A., Reference to..... 410, 411, 662 LAK® Nipigon basin, Sketch plan of.... 199 — Valley beds, New Mexico........... 326 LANDES, Henry, elected Fellow........ 617 LANDSLIDE in shales at Cleveland, Ohio, (plates 105, 106, 107)... 625, 627, 628 LANE, A. C., cited on “connate”? waters. 169 —, Reference to..... 661, 662, 663, 665, 699 LARAMIE (so-called) of the Raton coal field, Unconformity in the.... 357-367 LARIKAI valley, Saint Vincent, Figures SIO WAI th cee secs Lae se eet aa 2 he LARSEN, EH. S., and Fred E. Wright, Quartz as a geologic thermometer (abstract) LARSON, J. A., Reference to. .5...-..... DAV AS in Ice House canyon, Succession 10 as nea eer rc GRE tce es A Glare a MP ae 259 —-—the Silver Peak quadrangle, Suc- cessions0f 3. ea eee ee 58—261 —of Silver Peak region, Summary of SUWECESSIONMOER span nee oe ieee 261 —, Rhyolitic and dacite.......... 254-255 LATITE-GRANOPHYRE, Analysis of...... 2 LAWSON, A. C., appointed on Committee CERGONSernvyaATlOM) =: (os see ee 33 ==, ILAIGGOITENG SUNK Wthys gaeoo sun 4 cacw < 200 VERE EING Oa UOe oa cio rclisics y ace ehes ore ieee ae 662 —, Thesis and summary of trap sheets LO Ossie Soe HGS UIE SIC RICH Aare Ea Ran 200-201 LE CHATELIER, , Reference to..... 671 L&E CONTE, JOSEPH, cited on Columbia Nav aetlelasieuarimegcesta sc aneaienie sonore 210 —, cited on ‘‘Laurentide revolution’’... 482 = VCR RECTICO ce LO boirensiek ciel apey oes acie. tie oseies 482 LEE, WILLIS THOMAS, Paper published as pages 357-368 this volume, by.. 621 —, Reference to = MULE LOt A OC iy Vision ueutes acts rareusesiecrouens 357 LEHMANN, , cited on veins or dikes OLVONLATEEZ hi chare een eased oman cuet ares 36 LEIDY, , Reference to his work on exdiniete slot tribes sms ssc: 353-356 LEoNA heights, Pyrite mines of....... 707 LESLEY, J. P., Reference to report of Rennsmivania, SuUbVvey. Dyess nee. 164 LEVERETT, FRANK, Reference to occur- rence of Lepus and Mephitis by... 342 —, Reference to..... 134, 141-143, 639, 643 —, Weathering and erosion as time MUCASURESM (ADSEEACT)E ai deus scl enee 638 Lf&vy, MICHEL, Reference to..... 661, 662, 663, 664, 665, 666, 667 LIBRARY, Accessions to, November, 1908, to November, 1909.. 11 LHBRAR VAN EEC OI Ol. ctemmiclens a sicnere 615 LIME-SECRETING organisms, Calcium for MEGCGS MOT. Loran wocetm sels co aoa eee 163 LIMESTONE, Cherty Burlington........ 266 se TOL SOM k yrensuetad eames, cho, aeten alien Ore ene enle Bye, —quarries near Buffalo and _ Louis- WANK. VOMBNKSSY Sino yaboles 6S 56 aos oo ola eo LIMESTONES, Analyses of types of. 163-164 —, Canada and United States Ordo- Val CMA ese say es Manas Pana echenehe tees soe eeen retains 164 —, Chemical origin of Cambrian and | OME CRin AGHA So Soo mae boo come oe OD —, Chouteau and Burlington..... 321-323 =— Oh wolhoipiom Cie Wes aoe dna to bese 153-168 ==) lordooehnlorn wore sas helolejas aiaiond oro ola cuule 155 — Grain of the pre-Ordoviclan....... 167 —, Origin of early Paleozoic and pre- Gap rian cia ce cekeoee ace eeadea coe 163 —of Belgium, Reference to Firket’s jOAODIE Oil)’ od ad aoe ons de onlae ou oic 64 —of the Piedmont in Maryland and Virginia, Character and structural relatlOnswOheuinerr ary aaete eee cacke lems = wOitawal Ghver we aleOZOl@a mia cs ties 159 SP OTAO MSU O lsd io deck nemeieneeeaietets Caco ees 170 a= VOCKRORG) ZOMIaMihe) =r aeieiercie cis eiceene 325 —,Siveh and Sheppard siliceous...... 168 —, Summary of origin of pre-Devonian. 167 LINNEY, W. M., Reference to.. 621, 623, 624 Lissoa, Dr. M. A. R., Reference to.... 1 LOEW, Oscar, cited on desert varnish OLEENe MOT avieMGeSericnesie sci aie oe: 229 LOEWINSON-LESSING, Reference to.... 662, 665, 667 LOGAN, SiR WILLIAM, Reference to.... 200 —, Reference to his “Geology of Can- CG Baas Se rp Or Ea! ae Neher eae ree ae pes 164 LOGAN, W. N., Reference to.. 435, 455, 581 LONE mountain, Granites of.......... 250 LOSSEN, LEE LEMCeC LO ane cere 665, 667 Low, WOURVGTOFrEN CEN TOM so) us o.cvene bierecs 543 744 LOWE, ; Reference stoans: eee eee 430 LOWER Cambrian carbonate rocks, Anal- ysis of —-— of the Silver Peak quadrangle, Composition of 23 LWCAS, JRE OAC. References tone ene 351 — —-—fossil fish of “Esmeralda for- mation” LULL, R. S., Reference to... LuND eS W.. sRelerencentonneeee eee 2 e) 6 2s 2) «(6 = = leis). Ne! «lade telielintelietieiciie wells oe) ops: (alley etelese. een) wsel.e tate (eee LYLE, Reference to explorations in Nevada and” Arizona. sooo. .... 252 MACBRIDE, T. H., Reference to. 134, 400, 401 MacDouGaL, D. T., Origination of self- generating matter and the influ- ence of aridity on its evolutionary development, paper by............ 704 MACMILLAN & COMPANY, Reference to.. 394 MAGNESIUM in limestones, Average EAtiOn ObscaAlcigimM lOmin oe 163-165 — precipitated from sea-water........ 163 Macotruy formation, Atlantic islands.. 672 MALLARD, ~ ARGFErence)-tOe eis cee 671 INEAREMAT VA> a) CONOZOMCH cetiee a eeieiiele oie 704 MAMMALIAN fossils, Aftonian..... 401, 402 MAMMALS in Aftonian gravels of Iowa. 137 —of Aftonian fauna, Species of...... 343 MANGANESE in desert varnish......... 229 MARBLE, Red Saint Joe...... 269, 323-325 MARGERIE, M. DE, Reference to........ at MARTINIQUE, Eruptions in island of 409-416 MarTIN, G. C., Reference to.. 580, 594, 612 MARTIN, LAWRENCE, Alaskan earthquake Of OOO OS ee ee eae oe tee nee 625 — WRETCLENCCMLOLE Sie See eee eee 625 MARSH IO) (Co Reference: tO. - sacra 655 MARYLAND and Virginia, Character and structural relations of the lime- stones of the Piedmont in....... 679 = LTOM OLEES) (Oli os aces che els oe oe eee 671 —, Map of sections of Jennings forma- hHOnLOL, Western] =] ee eee 677 —, Recurrence of the Tropidoleptus fauna in the Chemung of......... 680 MASTODON of the Aftonian fauna..... ee ——. Reference) fo sWaLrren. ..2.cm ae eee 352 MATHEWS, EDWARD B., and J. S. Grasty, Character and structural relations of the limestones of the Piedmont in Maryland and Virginia........ 679 MATTHES, FRANCOIS, Glacial character of the Yosemite valley... 2... s- MATTHEW, G. F., Reference to. 436, 518, 528 MATTHEW, W. D., Reference to... 436, 600 MAYNARD: “EP: Reference’ £0: =. 2s... = McCONNELL. 7 IteLerence 10m sc, 32 6 McGer, W J, Reference to Pleistocene geology inh Towa 3 2.oe6 ease eens = 134 — —— “forest bed’ by — — -— ‘Pleistocene history of north- 430 MCGINNIS, Reference 102... . =... MEEK, , Reference to. 554, 559. 560, 572 MEGALONYX, part of Aftonian fauna, TNE he bois ene ene RE ee 353 MEMBERSHIP, Condition of........... 610 MENDENHALL, , Reference to...... 430 MERRIAM, JOHN C., Reference to.. 244, 598 MERRILL, G. P., cited on desert varnish in? ‘Poole: valley. Wtall oer cir 229 —, Historical notes on early state sur- VES. ciercin) so chaxsuatoeeee PS ee 671 —, On the serpentine of Montville, New Jersey, Reference t0:=.0. «42 eee 262 Mesozore era, Cretacic period of.. 587-597 — -—, Comanchic period of....... 583-587 ——, Jurassic period of......... 580-583 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA : Page MESozolIc era, Periods of......... 576-597 = ==, Mriassic) period, of.) 4-oeer 576-580 — floras, Succession and range of Ter- tiary. and 2.2.2. .3..25) 6 eee 704 — invertebrate paleontology of South America, Reference to... 9 5050m0 —-— faunas, Suecession and distribu- tion. of later ........ eee 704 -. 371, 394, 397 MILLER, ARTHUR M., Abstract of paper on Kentucky coal fields, by....... 621 MILLER, BENJAMIN L., Erosion inter- vals in the Tertiary of North Caro- lina and Virginia, paper by... 673-679 —, Reference’ to :.:.../. 22 646 MILLER, W. G., Reference to fauna of Lake valley described by......... 326 MILLER, WILLIAM J., Pleistocene geol- ogy of Adirondacks, by (abstract). 635 MILLER, , Limestones of Ontario.. 164 =|; Reference to) <2. 220.0 D eee 373, 383 MINERAL ridge, Lower Cambrian and pre-Cambrian time of MINERALOGY, Bibliography of Brazil. 1-132 MINNIGERODE, B., Reference to... 385, 386, 392, 393 MOLLUSCAN fossils in Aftonian sands.. 402, 403 MISSOURI valley, Aftonian exposure in. 140 MISSISSIPPIC formations, Table of.... 548 MOEBIUS, , Reference to::..3 Smbaee 385, 386, 389 MotarR of Mammut mirificum Leidy, Wigure . Of. 22... .4 566 Coe 355 MOLLUSKS in Aftonian gravels of Iowa. 137 MoRAN, ROBERT, Neocene of the upper Salinas Valley region, paper by... 708 MountT PELE, Avalanche action on. 412—413 —, Figures showing sand-blast action . «o/s Sib duals events 2 oo eee ~ 410, 412 on —, 1902-1903 eruptions of........ 409-426 MURCHISON, . Reference to... 513, 514 Murray, SIR JOHN, Reference to cal- cium sulphate now dissolved in the OCCA cc. ei snes he. «oe eee 166 —, Reference 0. <2... 4.552 159-160 MATTHEW, W. D., Reference to.... 347, 354 MYLODON, Figures giving view of claw OF oe. sheeswareis cre. cee ee 354 —of the Aftonian fauna............. 353 NANTUCKET Sankaty beds, Age and geo- logic relations of the..3.---o2eee 701 — shorelines, Papers III, IV......... 670 NATURAL gas deposits, Locations of.... 337 == =, Waste! Of 23.55... 0 336-337 NEWBERRY, J. S., Reference to....-.. 437, : 470, 574, 642 NEOCENE river gsravels...... 4s 246-247 —of the upper Salinas Valley region.. 708 NEOPALEOZOI@ efa .2-..- 22s 532-576 —-—, Devonic period of......... 540-546 —_—., Mississippic period of...... 547-552 —-—, Pennsylvanic-Permic period of.. 555-576 — —, Silurie or Ontaric period of. 532-540 —-—, Tennesseic period of.-.-.-.- 552-555 NEw Mexico and Arizona, Reconnais- sance along the Santa Fé railroad in. ‘western... ...02.502ee cee 700 . Raton coal. field of 3... ee 357-367 New York, Drainage evolution in cen- tral 2. és ieeeeed ee cee eee 668 NruMAyYR, M., Reference to...:.-2-.-5 432° NEWARK formations, Reference to..... 438 NEWSOM, JOHN F., Reference to...:.. 325 , Structure of the central portion of the coast ranges of California..... 708 INDEX TO VOLUME 20 Page NEWSOM, Tennessee, View of quarry- face showing disconformities..... 442 NeEvapDA, An old beach terrace in...... 707 NICKLBS, 5 LeMESIRSINGD W0caodoncou. 530 NICOLAS, , Reference to general in- GeOxmO hie p hic Ae eats aunt © aie Gye allelic allan 431 NIPIGON basin, Post-Cretaceous geologic HMSO Teen Olen Wena Mactray sues isi dies scilecier sasive 6 222 — region, Character of the pre-existing HOMOGE ADMY AOR aie coslecere ese oct el cle 219 emer bowe oF denudation of... ..--.- 219 liver Gorge Of THEs. ons c68 cc. es ss 202 NORTH "AMERICA, Correlation of Middle and Upper Devonian and Missis- SOONG TkEVOMNES OH so660000000000 703 ——, Continental seas of.. 446, 480, 481 ——, Catalogues of literature pertain- TOE? 10) FXONIGEAY OES bo capogacuc 430-431 —-—, Hmergences of ............ —-—-—and submergences, Table of... — — geologic formations, Classification into periods and eras of..... 513—6V0 — —, Glacial invasion of............. ——, Paleogeography of 429-606 —-—, Physical and faunal changes of Pennsylvanian and Permian in. 7038 — —, Physical and faunal evolution of. 703 ——, Regional movements of.... 500-503 — —, Revision of Paleozoic system in. 659 —-—, Table of inundations of........ 601 —-—, Tertiary drainage problems of CaseteMem sega, sis she acess wa adeeb ke ae — —, Transgressions and invasions of. 508-510 — Carolina and Virginia - Cretaceous floras, Geologic relations of...... 655 —-—-——,, Hrosion intervals in the rats AMV am Ole wane vive leieh cites ‘ove als "ees Sule NORTON, W. H., Reference. to......... NORWEGIAN marbles and dolomites.... COONS Changes in chemical condition OME Tae aN ew Biwletioes eter — OSIM ALeG: ALE Of acs see ee ce ee es —, The pre-Cambrian a fresh water... — water, Composition and changing toes OCBHANIC level, No such condition as. OHBPRN, D. W., Reference to.......... Onmoscorlspeds) Duration Of:.......... OFFICERS, Correspondents, and Fellows, TLESIE GIR Seam ec een ee ee 721-733 OOO Mmm LeCtlOMe Olen = 4c.-5 6 ue es OsIBWA lake, Last of great glacial lakes. 639 OKLAHOMA red beds, Present knowledge OIE Sp Sea OL eae reat ee OMBABIKA narrows, Diabase sheets in.. 206 OouitTES, “Hggs’ of the Belt-Cambrian. 168 OrE deposits of Silver Peak quadrangle, IR@ieTGMGS iO) Baw os ores blo ye eo oe 225 OrbDOVICIAN limestones, Canada and LOIN 2Y [Se Sy oe) ek oa ae eo 164 — sediments, Composition of......... 243 —-—of Silver Peak quadrangle.. 243 OROGRAPHIC origin, Valleys of Silver Peak region Oe Tacs Hae Cee CeO ae 263 ORTMANN, PRNeGEneMCe Ome sce 434 ORTON. EDWARD, JR., The Mills moraine and glacial drainage of Longs Peak (COLOEAGO) MGISTRICHE see so ae eects 671 OSBORNE, HENRY FAIRFIELD, Hnviron- ment and relations of the Cenozoic mammalia —, Reference to OO Ouse Oe RECT CCS CHC HICH CH Yanan SC De} sso do bo OMY BOS, BI, GOO) OSCILLATORY seas, Strand- lines and 511, 512 OSTWALD, ———. Reference to. 386, 388, 390 ues and other rivers, Comparison Ro Cie NIRA AT ae in, sce eal alc ae ar eas een ae Page OTTAWA river, Analyses of........... 157 — —, Largest pre-Cambrian area : GraineG bye 7s se earns nese ohare 158 OUACHITA region, Geologic history of.. 646 OWEN, RICHARD, Reference to Mylodon GOBUSLUS DY. a ikia aia eee 353 PaciFic coast Tertiary faunas, HEnvi- ROMM ENE Obie seisis ste eto atone ra are ees 704 PALEOGEOGRAPHIC maps of North Amer- Gal, IDESEBYOWOIN CE sootosouac 513-600 ne POGR AEE Areal-geologic method ee en aye any laleel nett on eee 46 —, Classification of methods of....... 437 == STMT OMG Obese ye eye Sieve at oc occas eovwy a onere 431 a ’ Diastrophic MELHOGMI As Giese Sees 447 a I SUORY. Ol uh hoes sia aene eile Sua esi lels 431-436 = MGtIHO G Sig Olivas nes oie mieeones states s 437-447 —of North America, by Charles Schuch- (2) GLb ee Recast RURAL CO CRORE race ee 429-606 —, Paleontologic method of...... 437-446 ——) Petrologicumethod! (ofe. ~ae ss ose 446 —, Robert Etheridge introduced term. 431 PALEONTOLOGICAL Society, Committee appointed for organizing......... 660 PALEONTOLOGY, Bibliography of Bragir in PALEOZOIC, Harly and middle......... 703 —era, Acadic period of.......... 520-522 —-, Canadic period of......... 526-529 —-, Cincinnatic period of...... 530-532 —-—of Silver Peak quadrangle.. 238-239 —emergences and submergences...... 479 —formations, Limestones and _ dolo- Mes hOh realy AS cents aie we ere 155 —-—, Georgic period of.......... 516-520 —-—, Ordovicic period of........ 529-530 —-—, Ozarkic period of.......... 522-524 —— —— "Periods OL vies sent ee ot 516-532 — lands, or positive elements.... 464-475 — limestones and dolomites, Origin of CATV y aie See sis yan Moss ois eter eer eesS 163 — locality, Cincinnati region......... 445 — positive elements, Geographic names OL ees Sie a a ethos aoe eee rae ae 467-475 SSS Ma OLS Coeiaitie d lels sues eee os 464 ays in North America, Revision GEA ee Se ES GSE — sedimentary series of Silver Peak quadrangle see. soe ee cee. 238-243 — time, Dana cited! ons. ..5..5..6-.- - 515 = MapiOf "SCas: Of. oie. eis ai diene aes 446 PALMETTO mountains, Rhyolite tuffs at DAS OT AO tat oon cates, teey poceeaccssermuaratel o ahw atte 2 PALLISTER, H. D., Reference to....... 627 PARAMETERS, Law of the rationality Of ee rs eo mettanhe wdiatct cle 387, 390, 393 PATTON He Bs neferencentor. . o. se 661 Prati Ay o@.) Reference toe... .5 oe 04 546 PEAT beds of Aftonian stage in Iowa.. 399, 400 —— —Jowa, The Oelwein and Afto- TOUT Me RR aR ee aap ese enter tien eee em 139 — deposits, Lower Sacramento and San HORGobiaY IHS so ooaaosdaaaooooc 707 PELH, 1902-1903 eruptions of mount.. 409-426 PENCK, ALBRECHT, Paper on intergla- ClalimepochsS se by) saskatoon 633 —, Reference to..... PENNSYLVANIA coal 633, 637, 638, 659, 670 area, Number of ACES iwaaMBNAIINE Tle og oponsodubpuos 335 PENNSYLVANIC Permic formations MAGI O Lee NUN ser te eek a a cena heer ea 558 — time, Reference to............. 439 JEIKO IONS Th PWeUll OG Gund Bho 6 Oa coloo 148- 149 PETROGRAPHY, Use of “‘Ophitic’’ and re- VATE eterimilSp Almere sc. etal eiehe 661 746 Page PERKINS, G. H., Reference to......... 521 PHILLIPS, JOHN, Reference to........ 666 PHILLIPS, P. LeE, Reference to....... 2 PHOTOGRAPH Committee, Report of.... 703 PIEDMONT in Maryland and Virginia, Character and structural relations of the) limestones of the: 4... 2: 679 PINCHOT, GIFFORD, Reference to...... 633 PITTSBURG coal bed, Annual production PE OM se! ae eae era ea te eae ee eee — region, Problem of coal shortage in. 335 — vein, Coal saved and utilized in.... 336 PLEISTOCENE detritus, Early terrace of plate S)eihcm aeee een geen: 248 — features in northern New York, by he Hailes iscsi cvewesa sucteheanene 635 — geology in Iowa, Contributors to ROMO Ue Ota eee eisie aia stewetnen wales 134 —, Physical geography of the......... 704 === Problem im WoOwalens 2). wecieceis ouen 133-152 PLACENTICERAS from the Thayer beds.. 138 PLAYA deposits in San Antonio marsh. 249 POPE, , Reference to......... 373, 383 POLARIZING microscope, Determination of crushed minerals by.......... 708 POST-CRETACEOUS geologic history, Sum- THEY LOE tS creed aici ere aoa etna weSeueae Papp Post-HURONIAN revolution, Effects of. 156 PRE-CAMBRIAN and later river systems, Chemical contrasijvokawn-- ee — -—post-Huron interval, Chemical changes in ocean during......... — correlation, Basis of principles of.. 703 — complex, Location and composition Olohnticns Megs soho hon ensure eee titote routine 230 SAP UMA so ine, oes scarier, jenn os ola neceatheme tenons 168 — formations, JT.uimestones and _ dolo- TGCS OE ete eo temeucucsekaiensmeeseeaeins 155 — limestones and dolomites, Origin of. 163 — terranes, Rivers draining.......... 160 JPRIO DON GW AGUAS SSCS! Oligs 6 5a 550500005 438 PRE-DEVONIAN limestones, Summary of a origin of PRE-ORDOVICIAN limestones, Grain of... 167 PRESIDENT, Annual address of the So- CHEE IS id aden at apemera: wise eaeleeas eats 133-152 PROBOSCIDBANS, Aftonian 351-353 PROCEEDINGS of the Twenty-first An- nual Meeting, held at Baltimore, Maryland, December 29, 30, and 31, including proceedings of the Twentieth Annual Meeting of the Cordilleran Section, held at Stan- ford University, California, Decem- ber 30 and 31, 1908; Edmund Otis Hovey, Secretary 608-736 BR ORE HOZONS era, Murchison cited on t ee aa aire natlrrcaee tc aretaurenieuel eiien eashisl ane — —, Sedgwick cited on the...... 518, 514 Prosser, A. C., Reference to...... 547, 568 Prossmr, C. S., Reference to.......... 680 PROUTY, , References tO... 2...6 56. 537 PUMICE beds in conglomerate of Hsme- ralday formations eis e eee PUMPELLY, R., Reference to.......... 665 Purpura lapillus, Distribution of...... 444 PYRITE mines, Leona heights......... 707 Pyroxanm, Analysisimof. sme cree nels 262 PYROXENITE, Formation of....... 261-262 QUATERNARY deposits of Silver Peak quadrangle 247-249 QUARTZ-DIORITE of Silver Peak range... 252 QUARTZ-MONZONITE from Silver Peak range, Analyses Of crested meus 251 ——of Silver Peak quadrangle... 250—252 QUARTZ-MONZONITES of South Carolina. 668 oc ee eee eee eee ee es BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA Page RABAKA gorge, Saint Vincent, Figures SHOWING). siesta es bes 2 ee ee RANSOME, F. L., Reference to..... 171, 430 =, Kteference! to datites oem soe c eee 257 RATON coal field, Conglomeratic base of. 363 == = WILOSION and Sapien 364 — + =, Nlorasof: 42.8 sah eee 366 —= == —., Key. map: including. eee 358 — —- ——, Location and “conditionmon reoks deseribed Gani. 4a semen 8-359 RATHBUN, RICHARD, Reference to..... RAYMOND, C. W., Reference to. 546, 562, 571 REINHARDT, C.,, Reference to...) oeee 389 RHEINHARDT, J., Reference to........ Pe RHYOLITE lavas, Form and composition OF os is aaew ae: cece 55 — ridge in Silver Peak reciens) eee PaByT — sandstones of Silver Peak region... 255 RHYOLITE-TUFFS, Figures of. Qeeee eee 229 RHYOLITIC lavas, Analyses of, by George Steiger <=. ...3.5 eee 256 =a Ot WNilver Peak Tansee De RED TOCK wc. vas bes 8 eee 207 REID, Harry FIELDING, “Geometry of PALES ois Bees eee iees cea 171-195 —, Paper on faults, published as pages 171-196 of this volume, by....... 625 —-—-—mass movements in tectonic earthquakes. by 7. 50-2 625 —, Reference to: ......250 550 nee 625 Report of. the Council... eee 609 ——-———— Secretary ........5- eee 609 — —— —— Preasurer 22... 6.5 eee 612 == = Nditor —. one. eee ee 614 —-—— — Librarian...) -555- 00 615 —-—- Committee on Geologic Nomen- Clature. .ciss-s, Scissor 620 Rick, W. N., Reference to... eee 661 RICHARDSON, GEORGE Burr, elected Fel- VOW.» 5 lo: sie! o-Guiss eaeve bathe eee 617 RINNE, , Reference’ tos aoe 662 Rock formations in the Raton field 359-361 6 Rocks, Intrusive: granitic sone eee ae, —of the pre-Cambrian complex...... 226, 231—238 ROGERS, ; Reference: tOas aces oer 655 RoaceErS, A. F., Minerals from the coast ranges of Californias. .-e eee T07 —, The polarizing microscope......... 708 —, Experiments with a shaking ma- chine: 3 eA ee ee eee 707 RocGers, H. D., Reference to.......... 450 Rocers, W. B., Reference to.......... 450 ROMINGER, , Reference to... 2.2.58 Hoe ROSEAU valley, Saint Vincent, Figure showing: 2.8 05..00.52 =0CGneoe 416, 420 ROSENBUSCH, H., Reference to....... 662 665, 667 ROWLEY, , Reference to. ane 547 RoyAL Society of London, Reference to. 410 418, 422, 423, 424 RUEDEMANN, , Reference to...... 526 528, 537 RUSSEL, I. C., cited on Columbia fields. 210 =+, Referemee to oi dsa% de Oe ee 421, 579 RUTLEY, , Reference, to. 42-5 ose 662 SAFFORD, ; Reference to... =. eee 470 SAINT GENEVIEVE county, Missouri, Fern Glen beds exposed in....... SAINT JOE marble, Distribution of.... 269, 323-325 ——-—, Table comparing Fern Glen fauna. “withe 4..c Ee eee oe 324 SAINT JOHN, -——, Reference to...... 401 INDEX TO VOLUME 20 Page Saint Louris Academy of Science, Ref- = CRETICOWH Opec ere leis co etceeile os sis peneaete ans 265 SAINT VINCENT, Creation of shorelines. 423426 — —, Eruptions in island of...... 417-426 ——, Figures showing gorges and val- leysq (On SOULEICLE.. 5.0.5 «iss. 414-416, 418, 420, 424 —-—, Rabaka River valley....... 424, 425 SALISBURY, R. D., Physical geography Gi WOES IPUSISOYENES Gag om Ooo non oo —, Reference to........ 165, 434, 447, 464, 505, 509, 5138, 608, 605, 642 SALOMON, PRVCKCECNICE) Ok Gas eerie SALurt Lick Fern Glen beds, Thickness Olt ole Se BERG ae Oe eee een EI ware 268 SAMPSON, F. A., Reference to Fern Glen COMEEHONS Ohi evee ire smaereces seu deaaennt Sve 69 SAND-BLAST action, Striations produced BDV AMR Nes tee eae al ira wie uemsae lence 410-413 SAND dunes of Silver Peak region..... 249 SANDS and gravels, Western Iowa Af- [EOTOITOU LO Sy ae ch alee aS tigate ten aes 399-408 — bearing molluscan fossils, Aftonian. 402, 403 SANGAMON IMPCE VAL so. jei See ess see 6 143 SANDSTONE, Age of the Gaspé........ 688 ——woonnecticut valley ...2......0% we 437 SANDSTONES, Rhyolite in the Hsmeralda HOMEMIMEA OWI tae ci o-tee. cele alicia le ceai daavece 255 —, Trap sheets underlying Keweena- TIMP SRG cpt atren es ccviacis here nents, uaa 207 SANKATY beds, Age and geologic rela- HONS Ot NAMtWweKet 5.5. <0 2. eee 701 SANTA LucIA mountains, Reconnais- sance about the big sur-region of IUGR ere ica ce, sileiicrsitss 21.0") s..6 «jeer wile leire 708 SAPPER, KARL, Reference to.......... 590 SAVAGE, T. H., Reference to...... 134, 136, 400, 537 —, Reference to description of Aftonian IGA tMCOS Yes ttle endccirs owe sre of co eceane 139 SCHISTS, Caleareous augen-.......... 231 (Come! TAUSEN=. =. se ws eee s 6 teu 231 —of the Silver Peak quadrangle.. 231—232 SOHNCKE, L., Reference to....... 386, 388 SCHOENFLIES, A., Reference to... 370, 371, 385, 386, 393, 397 Scorr, WILLIAM B., Reference to.. 354, 436 SCHUCHERT, CHARLES, Paleogeography OFeNOMeh AMERICAS <0. < ssc e's cc cess 659 —, Record of remarks on age of the Gacspe formation 2.5: ..2.2.- 695, 696 —, Reference to examination of grapto- ES eeeiee cprelsirctOhareis, Beate etenls te weve leveneis —, Reference to......... 436, 450, 452, 457, 461, 470, 483, 486, 490, 501, 506, 526, 5738, 603, 689, 694, 697, 698, 700 Ge MOE. PAPEL DY. \:c ide este eee ss 427 Seas, Map of North American conti- AUGIU ahaa ial icbodte (ois ie Wahetied an ot ehlonelaters 447 —, North American continental........ 446 SHGRMMARYE, SREDOLt- OF csc.) ccs. oie ce «si 609 SEDGWICK, ———, Reference to........ 513 SEDIMENTS, Chemical composition as a criterion in identifying metamor- DINGS CORB R PRS o etialcete Dols) Moneta alates 667 , Keweenawan and Animikie........ 198 SEISMOGRAPH, Proposed form of...... 7U8 SELLARDS, RELEreENee: tO), saci << e.s 569 SERPENTINE of quadrangle of Silver TEAS EPR, BEA ee ker Olle gee eae Pe ere teat te v3) 202 SHALE, New Providence.......... 325-326 SHAner, N.S: Reference to... i. ci..0.5. 621 SHATTUCK, GEORGE BURBANK, Some physiographic features of the Sha- WATS UMS MIO UMLAITIS) five sil sem ele ors 670 SHAWANGUNK mountains, Some physio- era phicy features! Oleic sacs cease © 6 670 SHiFrt, Horizontal and dip-........... yes Page SHIMEK, BOHUMIL, Aftonian sands and gravel in western Iowa........... —, Reference to “Aftonian sands and SEAVEIS HE DY mre eee uae Br here eae = OLELEMCO: LO s5 59 Ce ee 134-137 alate Or, PANE Dy a. stiecs sites One 399 SHIMER, H. W., Age and relations of the Sankaty beds.......... ejeickseane nk On SHORELINES, Creation of Saint Vin- COIN re ata t aici es cle eae 423-426 SHutTtT, F. T., Analysis of Ottawa river WL UO Tee Dpto cracls, cr aiccal scare ai aee 158-159 SIERRAN period, Reference to......... 248 SNAKE River fields, Basalt in......... 219 SILVER Peak quadrangle, Desert varnish OU ins Sich ee Ee nN A oe 229-230 —-—-—,, Drainage and water supply of. 227 —-——, Extent and topography of.... 226 2 ——-——, Geology Of 0 ...6 5.02. 24-264 = —— =, PASO BOIN “GE 4 non boo Gee 228 SS SS NOSINSAY OF obo 55 5ne05456 228-229 = SVE ShygjNiy Oaskodoge 227-228 = = HR, WBA). OES hou cobb ko ome oo 225 SILLS, Arguments in favor of intru- SUM OW sey ered seat eceh en meee tie Genet man oat ae By 215 (abstract). 671 SiLuric formations, Table of......... 533 659, 667 SMITH, JAMES PERRIN, cited on disper- sion of Purpura lapillus.......... —, Reference to 555, 561, 572, ; 576, 578 —, Synopsis of the stratigraphy of Cali- 6.0) 0/0) 1@)/6ie10) (0), O).0/ en @) ee) (eo Oba, paper Pye p ose: «oe ce me 708 SMITH, JOHN WILL, Reference to..... 682 SULA ELeETENCE | TOin. occa ec eae 439 SLOAN, HARLE, elected Fellow......... 617 SoILs in situ, Remnants of old........ 207 SOUFRIERE, U-shaped valleys of... 414-416 —, 1902-1903 eruptions of...... 409-426 SOLLAS and Sollas, Reference to... 434, 475 SouTH CAROLINA granites (quartz mon- Zonites), Petrolory of... 2. .0... 668 SOLUTE, The terrane and river........ 155 SPHNCH) EH. “A.; Reference to...4...... 418 SPENCER, J. W., Reference to. 630, 632, 670 SPRINGS near Silver Peak............. 228 SPRINGER, FRANK, cited on the Lake Walleye DOGS accasite cies ce coctoion se 326 Sprucre RIveR gorge, Diabase sheet in. 204-205 Spurr, J. E., cited on veins or dikes of CTBT EZ satay tos one oy Von e eros shstoaeuete,saeteee, 237 ——=, R@LETENGCE: tO) s.ccs ek dee ete ace 225, 248, 574 STANLEY-BROWN, JOSEPH, elected Editor. 616 ——, Report of Mditor..:..)2..5.... 614-615 STANTON, T. W., cited on marine in- vertebrates found in Trinidad sand- SLOnew inh waconateldcaus else cee 365 —, cited on the Ripley fauna......... —, Reference to . 430, 580, 581, 584, 585, 586, 590, 592, 593, 594 —, Succession and distribution of later Mesozoic invertebrate faunas...... 704 STATE surveys, Historical notes on GaP ve sie cas euaeteveetereseh eke Sroto ete rem one 671 STAUFFER, C. R., Reference to.... 640, 643 STEIGER, GEORGE, Analyses of pyrox- EIEN MD Vir ceyet a ou cus lewevai a ois v ener elie sboitoret ence ———rhyolitic lavas by........ 254, 256 === SS = SONS JOY octccecoeon moe 232-233 —, Analysis of basalt of Piper peak by. 258 — -— -—latite-granophyre ........... 257 — —-— quartz-monzonite gneisses by.. 230 —-—-yellow mineral corresponding LOmRCHVOLOMANL Wise teu-a: 215