ALBERT R. MANN LIBRARY New YorK STATE COLLEGES OF AGRICULTURE AND HOME ECONOMICS AT CORNELL UNIVERSITY The Laramie flora of the Denver basin, wi DEPARTMENT OF THE INTERIOR ALBERT B. FALL, Secretary UNITED STATES GEOLOGICAL SURVEY GEORGE Otis SmitH, Director i Professional Paper 130 THE LARAMIE FLORA OF THE DENVER BASIN WITH A REVIEW OF THE LARAMIE PROBLEM ce DE : F. H. KNOWLTON WASHINGTON GOVERNMENT PRINTING OFFICE 1922 on, ’ "oe G24 ee 214580 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 40 CENTS PER COPY CONTENTS. Page. INTRODUCTION. C2 ioieccee Leg etneda adalah Oe elon ioe seusueec uuetaaed eeu panes eon nam emERoeEsS 1 ‘Part I. Historical review of the Laramie problem...................------ Wh Ae aed pl seve res iia A neato 8 Early opinion concerning the coal-bearing rocks of the Rocky Mountain region...........-...--222----++ 3 Relations between the Laramie of the Denver Basin, taken as a standard, and the reported Laramie in thatend! other arcdskea. 450 ria tee itt bia ade aes c aelanetelsy ta aphex dune ohn Gals aan ace ites 15 Arapahoe and Denver formations...................-.---- ON MAS fie hee tint eta pericals } Aol ke dentine i156 Raton Mesa region of Colorado and New Mexico........... Jinchdd diet ARs eee tbeyselitee Base eOikete Soe aie ets 18 Colorado Springs area.................. dias euceetezre elses Baan tl Na cheats RE Fe Sainte eae ae 20 Tyance: formation’. C2 ieee ea eco hada eke e ely unetaule s Pe ahemna de cx ededgte oes ae eee eas eames 25 Fort Union formation............. Reise ¥ Santee wk skinned! Bt aunesheeces sahd Sesdaa ls doa eleaooy semanas 41 ‘“‘Laramie” in the Canadian provinces.................-.-- Bt hie yates ne dha Rithsesaeya ctetalara ae ae thot 43 “Laramie” and Livingston formations in Montana..:...... Oliaata sacl RO Roe te Sredivites Ss aap 48 Uinta and Green River basins.................-.22+.- peiiiow a Pabepauthe Wins shabasiee errr ee iene 55 Uinta Basin. ...........2.0.020022 eee eee dears ude beeeetieMerlauanaddezaunmyeekeaieamobee 55 Book Cliffs field, Utah and Colorado.........-...2.. 2000.0 cee eee e cence eee cee cece cece eeeeeees 55 Grand Mesa and West Elk Mouttains, Colorado..................00e0e eee cece ee eee ee eee 56 Glenwood Springs area, Colorado..................2.--0-- eer ene Lent iso eeateettn delaras Outta’ 57 Grand Hogback and Danforth Hills area, Colorado............2..22.000-00eeceecceeceeeeeeee 58 Green River Basin...............-.-.-2-2-20202020-0- ALA Ad Coe ID CA eR ARI Aare arn ty Aes! 58 Yampa coal field, Colorado... 22.2.2... .0. 0. ccc cc cence ee eee eee eee eee eee 58 Little Snake River area, Colorado and Wyoming aka hasatata rate iocedy catia cna Set isn ual Narco ta 59 Carbon County, Wyoming, and adjacent areas..............00.0000 cece cece ene cence eee ee 59 Black Buttes, Wyoming.............2.2.22- 20-0202 cece eee ee eee eee eee eee eee eee 61 Point of Rocks, Wyoming, and vicinity.............2..2-22-2--2225+ eda k teeta eg Beaee, (165 Southwestern Wyoming .............-.--.22-2--22-200+ po arate aeN Es a asrtec fet coF sist RAs a Athan 66 Coalville; Utah; and: vicinityios. cesauy ssi a sarenane x4 54 pease eee k meade hes ea eee yes eeeaeh 68 San Juan Basin and adjacent areas in Colorado and New Mexico.................-. 2002 e cece eee eee 69 “Laramie” in western Texas and ‘northern Mexico...........2.-... 20-020 e eee e eee ee eee eee cece 74 Judith River formation. .........2....... 2022-002 e eee ee eee ee Se oe oe eae 77 Bear River formation..................-.---- Seva oe ee nase teh ea a ah a es mom intend a as onion iley 78 Present usage of the term Laramie............-2.-2.22-022-020 cece cece eee eee eee eee 78 Is there a type section for the Laramie? ...............----0 00000000 e ccc eee eee e cece eee e eee e cee 79 Part II. Geologie relations and flora of the Laramie of the Denver Basin...........-.....2..222+--2--++-+-- 83 Lithologic and stratigraphic relations.............--2. 2.20220 e cee eee nee eee e ee eee e nee eeeee 83 Animal life of Laramie time in the Denver Basin..............---- 20-220 e eee e eee eee eee eee eee 84 Amber in the Laramie of the Denver Basin........- Perey SAae ck Loos teem tenetaad atc snes 87 Part Ii. Whe laramiefora. << scce0cv.c caoeceas segs sere earion cies Pe eee Ne ee ee 89 Bibliography of papers relating to the Laramie flora in the Denver Basin..............22-222-22-0020000-+ 89 Local distribution of the flora. . 2... 2222-2... cece eee eee ee eee ee eee eee cece eee e ne eeeteeeee 89 Difficulties in the study of the earlier collections...............-2.2222.0 2022002 e ee eee eee eee eee eee 92 Synonyms and changes of interpretation............ 2.2.2.2. 2-202 2 eee eee g4 Laramie-plants in the Denver Basin. oie ones ees peumsices ey es eeeese vee ys eustews sees si Geabeeeesasuee yess 95 Biologic relationis:of the: florase seis sainbcc dene see neice hoe sajacenier ee eaae ise Ped de dedAe he vielngaiss oe 96 Heologi¢velations Of the Morac. ccccoseimessianeesew ten oceiee sweet Oe Glee eee tea debecet eed 97 Geologic relations of the flora........... oaks ee AT Sec raiac oe tei ee eden Oca ene ten ee oomane teense TOO Relations to the Montana formations........-....--.--. 222-2022 2 eee eee 99 Relations to the ‘‘ Lower Laramie” of Carbon County, Wyo....-. aaa Sse ere 2 Safe & Seta RES 100 Relations to the Denver formation. ...-....-..-2.0- 20022 c cece cece nee ee eens aceasta oes 101 Relations to the Arapahoe formation. ......-...----.-+-2seeee scenes cece eee eens reece ecee revere 102 Relations to the Lance formation..........----22-- 2 eee eee eee eee eee eee Parte alee eos 104 Relations to the uppermost Cretaceous of the Atlantic Coastal Plain..........-......2..2..0.-00202-- 105 Relations to the Patoot series of Greenland........... 22. 2-20.22 cece eee eee eee eee eee eens 105 Relations to the Upper Cretaceous of Europe............. 222.2202 eee eee ee eee eee eee eee 106 The whl or ais 13 dec ssce sacs Sindee w ete seroma Gwe MRR Se DAR AE Gedvolatn aed oles eri eD Ore. BEA UlE Ria Nira Sete 107 INDEX cise eens cteeeks se eeeeee vs 34 dee sees dette os eels ceeded sce edn PSs iS en oe Ee eee ee 171 IIL ILLUSTRATIONS. Prates I-XXVIII. Laramie flora... . 2.2.2.2... 0. cee eee eee eee es Daas cane Mentnmemaeee Figure 1, Approximate correlations of typical formations of late Cretaceous and early Tertiary in Europe anid Western: AMELICa a siete x aie ybr ees bly eicveceeyera eevee ok int ere te ba la eam ee Sian wl ee ein tee Iv THE LARAMIE FLORA OF THE DENVER BASIN, WITH A REVIEW OF THE LARAMIE PROBLEM. By F. H. Know ron. INTRODUCTION. In the investigation of the Laramie flora which I began about 1889 it was my original intention to study the flora of the Laramie formation of the entire Rocky Mountain region, over which the formation was then understood and generally accepted as being widely dis- tributed. As a preliminary to this study the older collections, which had served as the basis for the work of Lesquereux, Newberry, and others, were critically reviewed. To this basis was to be added the new material that was becoming available in ever-increasing volume. It very soon became evident, how- ever, that opinion concerning the Laramie for- mation was undergoing a transition, during which, as will be shown in the historical review which follows, area after area was found to have been incorrectly or unwisely assigned to the Laramie. The work was consequently de- layed pending the settlement of these disputed points, and subsequent events have abundantly proved the wisdom of postponement, for other- wise the result would have been a composite picture and open to the same objections as those that fall upon Ward’s ‘‘Flora of the Laramie group.” ‘The revision of the older material, together with the descriptions of such new material as came to hand from time to time, has consequently lain in manuscript for many years, though it has been available and has furnished the basis for numerous ten- tative considerations of this flora. In view of the uncertainties as to the ultimate classification of certain of the supposed Laramie areas, it was finally decided to restrict this ac- count to an area about which there is little or no disagreement. The Denver Basin in Colorado offers such an area. The geologic relations of the Laramie as understood in 1895 were set forth by Emmons, Cross, and Eldridge in their monograph on the geology of the Denver Basin.* After the segregation of the Arapahoe and Denver formations from the Laramie, there re- mained the Laramie unit as now accepted, which is believed to fulfill in all essential par- ticulars the requirements of the original defini- tion by King. When the Denver Basin mono- graph was published, it was supposed that the coal-bearing Laramie rocks were present throughout the Front Range. Subsequent study has shown, however, that the Laramie is not now known to extend beyond Colorado Springs on the'south. This paper deals with the plants known from the Laramie of the Denver Basin, which is here considered as slightly larger than the limits set in the monograph above mentioned, extending from the vicinity of Greeley to the divide near Palmer Lake on the south. The southernmost exposure of Laramie rocks in ‘the Castle Rock quadrangle is in practical continuity with the Laramie in the Denver Basin and is separated by a covered interval of only about 18 miles from the nearest exposure of Laramie in the Colorado Springs quadrangle. To the east the Laramie extends for varying distances out on the plains, where, however, it is more or less deeply covered by the Arapahoe or Denver formations or the Dawson arkose. The material on which this paper is based was derived from many sources. Most of the original material on which Lesquereux based his studies is preserved in the United States National Museum and has been freely con- 1U. 8. Geol. Survey Mon. 27, 1896. ! 2 INTRODUCTION. sulted. It was collected in part by F. V. Hayden and in part by Lesquereux or by persons in correspondence with him. The very earliest collection made by Hayden, at Marshall in 1867, is apparently lost. The types of the few species described by J. S. Newberry are also preserved in the United States National Museum. About 1884 an im- portant collection was made for Newberry by N. L. Britton, now of the New York Botanical -Garden. The larger part of this collection came from mines near Erie, Colo., from which no additional material has been procured. Other parts of this collection were made at Marshall and on Coal Creek. All this material has been placed at my disposal by Dr. Arthur Hollick. Considerable collections were made by Lester F. Ward in 1883, but heretofore they have only partly been described. During the prosecution of the work which resulted in the publication of the Denver Basin mono- graph, Emmons, Cross, and Eldridge obtained a number of small collections, and under the instructions of Emmons larger and important collections were made by Arthur Lakes and G. L. Cannon. These collections, made in 1889 and 1890, have not before been described. A small collection from Crow Creek, near Greeley, was made in 1896 by T. W. Stanton and me. The largest collections obtained in recent years were made by A. C. Peale and me in 1908. The material in the museum of the ‘University of Colorado, at Boulder, has been placed at my disposal by the eastarlian: Judge Junius Henderson. cated by T. D. A. Cockerell, of Boulder; R. D. George, State geologist of Colorado; G. L. Cannon, of Denver; G. B. Richardson and ‘styles of plates in this report. Smaller eollestans or, individual specimens have been communi- M. I. Goldman, of the United States Geologica] Survey; and G. I. Finlay, formerly of Colorado Springs. Invaluable data regarding the sup- posed upper part of the Laramie were ob- tained by W. T. Lee, of the United States Geological Survey, in 1915. To these men and all others who have contributed to this study the appreciation of the writer is hereby ex- pressed. Notwithstanding the fact that these very considerable collections have been brought together, the flora is neither large nor very impressive. In the first place, although plants are widely distributed in the Laramie, they are rarely found in any great abundance. The matrix in which they occur is usually a soft, friable sandstone which is not fitted to retain the plant i impressions with fidelity, and, moreover, it is difficult to find perfect speci- mens. In attempting to present as complete a picture as possible of the plant life of. the time, it has frequently been necessary to characterize forms on rather slender data. It is hoped, however, that all are figured and de- scribed adequately enough to be recognizable in the future. A word should be said concerning the two Plates XX- XXVIII were made a number of years: ago, when it was the custom to make pen drawings of the specimens. These were drawn on an enlarged scale, requiring a one-third reduction to bring them to natural size. The figures on Plates I--XIX were photographed natural size and merely have had the outlines and nervation strengthened. The impossibility of having the two styles of drawings mixed on the same plate accounts for the scattering of the figures. \ Part I. EARLY OPINIONS CONCERNING THE COAL- BEARING ROCKS OF THE ROCKY MOUNTAIN REGION. As this report is the first of what is proposed to be a short series of papers dealing with the stratigraphy and paleobotany of certain late Cretaceous and early Tertiary formations in the Rocky Mountain region it is thought desirable to present rather completely a historical review of opinion which led to the establishment of the term Laramie and to its subsequent applica- tion. This review includes not only the Lara- mie formation in its typical area in the Denver Basin of Colorado, but also various beds at one time considered to be of Laramie age. For more than 60 years what finally came to be known as the “Laramie problem’’ has been more or less of a storm center in American geology. Its discussion has given rise to an extensive body of literature, and it is only within the last decade that a solution has been’ arrived at which, at least to me, appears to be logical and, it is hoped, permanent. ' The history of the Laramie formation, as. already intimated, is long and complicated, and the literature is widely scattered through a series of papers and reports in a manner that is very confusing to one who attempts to gain a comprehensive knowledge of it. articles have been published dealing more or less completely with the historical develop- ment of the Laramie problem. One of the most complete for its time was that by Lester: F. Ward,’ published in 1886. Five years later C. A. White * again reviewed the subject as it finally appeared to one who had taken a large part in shaping it, and in 1906 George P. Mer- rill * devoted a special chapter to the Laramie question, which he ranked with the well-known “Taconic question.” The ‘Index to the stratigraphy of North America,” by Bailey Willis,> also contains valuable data on the Lara- 2 Ward, L. F., Synopsis of the flora of the Laramie group: U.S. Geol. Survey Sixth Ann. Rept., pp. 399-557, 1886. 3 White, C. A., Correlation papers—Cretaceous: U. S. Geol. Survey Bull. 82, 1891. ‘Merrill, G. P., Con#Abutions to the history of American geology: U.S. Nat. Mus. Rept. for 1904, pp. 647-658, 1906. 5 U.S. Geol. Survey Prof. Paper 71, 1912. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. mie formation, especially as regards certain of the later phases of opinion regarding it. Although the term Laramie first appeared in print in 1875, it is essential, to understand the conditions which led up to the use of the term and made it necessary, to go back at least as far as 1854, the date which marks the beginning of F. V. Hayden’s explorations in the Missouri River region. As Ward * says: From the circumstance that at nearly all places where it has been recognized it consists to a greater or less extent of deposits of lignite or coal, this condition was for a time inseparably associated with it to such an extent that there was a disposition to regard all the lignitic deposits of the West as belonging to the same geological formation. Prior to the work of Hayden the presence of coal in the upper Missouri River region had been noted by Lewis and Clark in 1804-1806, by Nicollet in 1839, by Audubon and flares ‘in 1848, and by John Evans in 1849 and 1853, but very little was recorded by these ehseruen: concerning the geology. In 1853 F. B. Meek and F. V. Hayden were employed by James Hall, then and for many years thereafter State geologist of New York, to visit the bad- lands of White River for the purpose of mak- ing collections of Cretaceous and Tertiary fossils in that region. They brought back | extensive collections of vertebrates and inver- A number of tebrates, the latter especially from the vicinity of Sage Creek and several localities on Mis- souri River, mainly below Fort Pierre. Sub- sequently Hayden spent two years in explora- tion and in collecting fossils in thé same gen- eral region, and in 1856 he again visited this country in connection: with an expedition under the direction of Lieut. G. K. Warren. The data acquired on these expeditions re- sulted in the publication of a series of valu- able papers in the paleontology and geology -of the Missouri River region, or Nebraska Territory, as it was then called. The first of these papers was written by Hall and Meek,’ and although it was concerned mainly with ® 6 Ward, L. F., Synopsis of the flora of the Laramfe group: U.S. Geol. Survey Sixth Ann. Rept., p. 406, 1886. 7 Hall, James, and Meek, F. B., Description of new species of fossils from the Cretaceous formation of Nebraska, etc.: Am. Acad. Arts and Sci. Mem., vol. 5, pt. 2, pp. 379-411, 1855. 3 4 LARAMIE FLORA OF the description of new species of invertebrates it contains (p. 405) a geologic section under the heading “Section of the members of the Cretaceous formation as observed on the Missouri River and thence westward to the Mauvaises Terres.” The stratigraphic units of this section, which practically correspond to those accepted at the present day, were numbered in ascending order from 1 to 5, but they were not then named. Above the Cre- taceous portion of the section was recorded the Eocene Tertiary, which was given a maximum thickness of 250 feet. In 1856 the elaboration of the invertebrates was continued by Meek and Hayden,* who quoted the geologic section from Hall and Meek without change, except that the Tertiary was given a thickness of 400 to 600 feet and was said to be composed of “beds of clay, sandstone, lignite, etc., containing remains of vertebrates and in places vast numbers of plants, with land, fresh-water, and sometimes marine or estuary Mollusca.” As regards the Cretaceous portion of the section they stated: It is worthy of note that some of the species contained in the colléction from the most recent Cretaceous beds of the upper Missouri country appear referable to genera which, according to high European authority, date no further back than the true chalk, while many of them are closely analogous to Tertiary forms—so close, indeed, that had they not been found associated in the same bed with Ammonites, Scaphites, and other genera everywhere regarded as having become extinct at the close of the Cretaceous epoch, one would have considered them Tertiary species. On subsequent pages in the same journal Leidy ° began the publication of the results of his study of the vertebrate remains from ‘the Judith River badlands. He did not discuss the age of the beds, but in the description of the final species, which was named in honor of the collector, he said: ‘“‘This species is named in honor of Dr. Hayden * * * and which remains, I suspect, indicate the existence of a formation like that of the Wealden of Europe.’ 8 Meek, F. B., and Hayden, F. V., Description of new species of gastro- pods from the Cretaceous formation of Nebraska Territory: Acad. Nat. Sci. Philadelphia Proz., vol. 8, p. 63, 1856. ® Leidy, Joseph, Notice of extinct reptiles and fishes, discovered by Dr. F. V. Hayden in the badlands of the Judith River, Nebraska Terri- tory: Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 72, 1856. 10 This is the beginning of the so-called Judith River problem, which is considered on pp. 77-78 of the present paper. THE DENVER BASIN. In their second paper "Meek and Hayden took up the invertebrates that were believed to be of Tertiary age and incidentally briefly described the lithology and areal extent of the great lignite-bearing formation (=Fort Union) ‘of the region as then known to them. They showed that it occupies a vast area, ‘‘chiefly between the forty-sixth and forty-ninth paral- lels of north latitude and the one hundredth and one hundred and eighth degrees of longi- tude.” As their adumbrations, even in this first venture, regarding the age of this lignite- bearing formation are so nearly in accord with the modern interpretation, it may be of interest to quote their statement (p. 113) in full: Although there can be no doubt that these deposits huld a rather low position in the Tertiary sy¢tem, we have as yet been able to arrive at no very definite conclusion as to their exact synchronism with any particular minor sub- division of the Tertiary, not having been able to identify any of the Mollusca found in them with those of any well- marked geological horizon in other countries. Their general resemblance to the fossils of the Woolrich and Reading series of English geologists, as well as to those of the great Lignite formations of the southeast of France, would seem to point to the lower Eocene as their position. In the following year, however, Hayden ap- pears to have modified his opinion regarding the age of the lignite-bearing formations, for in a short paper? accompanying a colored geo- logic map of the country bordering Missouri River, he said, in discussing the ‘‘Great Lignite deposit)’’: The collections of fossils now obtained show most con- clusively that it possesses the mixed character of a fresh- water and estuary deposit and that it can not be older than the Miocene period. It is composed mostly of clays, sands, sandstones, and lignites and has yielded numerous animal as well as vegetable fossils of great perfection and beauty. It is chiefly remarkable, however, for the evi- dence that it reveals to us of the variety and luxuriance of the flora of that period. In a paper immediately following that one Meek and Hayden * continued the description ° ll Meek, F. B., and Hayden, F. V., Descriptions of new species of Acephala and Gastropoda from the Tertiary formations of Nebraska Territory, with some general remarks on the geology of the country about the source of the Missouri River: Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 111, 1856. 12 Hayden, F. V., Notes explanatory of a map and section illustrating the geologic structure of the country bordering on the Missouri River, from the mouth of Platte River to Fort Benton: Acad. Nat: Sci. Phila- delphia Proc., vol. 9, p. 109, 1857. \3 Meek, F. B., and Hayden, F. V., Description of new species and genera of fossils collected by Dr. F. V. Hayden in Nebraska Territory, etc.: Acad. Nat. Sci. Philadelphia Proc., vol. 9, p. 117, 1857. ® HISTORICAL REVIEW OF of the invertebrates of the upper Missouri River region, but before beginning the technical part of the paper they again went over the geology, of the region, reaffirming their conclusion that the lignite-bearing beds are of Miocene age. The next paper of importance dealing with the geology of this region was another by Meek and Hayden “ published in 1861. In a “general section of the Cretaceous rocks of Nebraska”’ (p. 419) the stratigraphic units previously known only by number first re- ceived the names by which they are now so widely recognized. These are as follows: ' No. 5=Fox Hills. No. 4=Fort Pierre. No. 3=Niobrara. No. 2=Fort Berton. No. 1=Dakota. Meek and Hayden also presented in this paper (p. 433) the first complete section of Tertiary rocks of the upper Missouri River region, given in the following sequence: Loup River beds. White River group. Wind River deposits. Fort Union or Great Lignite group. As we are concerned in the present connec- tion only with the lower of these divisions, the others may be passed over. Their description of the Fort Union is as follows: Beds of clay and sand, with ferruginous concretions and numerous beds, seams, and local deposits of lignite; great numbers of dicotyledonous leaves, stems, etc., of the genera Platanus, Acer, Ulmus, Populus, etc., with very large leaves of fan palms; also Helix, Melania, Vivipara, Corbicula, Unio, Ostrea, Pholadomomya, and scales of ‘Lepidotus, with bones of. Trionyr, Emys, Compsemys, Crocodilus, etc., occupy the whole country around Fort Union, extending north into the British possessions to unknown distances, also southward to Fort Clark. Seen underneath the White River group on North Platte River. Also on west side of Wind River Mountains. Their conclusion as to the age of the Fort Union was not very definite, owing largely to the difficulty of interpreting the somewhat conflicting plant and invertebrate evidence, but the facts that it had been observed beneath the White River deposits (regarded by them as of Miocene age but now assigned to the Oligo- cene) and that it contains certain vertebrate remains not known in Europe above the Eo- u Meek, F. B.; and Hayden, F. V., Description of new Lower Silurian, Jurassic, Cretaceous, and Tertiary fossils, collected in Nebraska, il with some remarks on the rocks from which they were obtained: Acad. Nat, Sci. Philadelphia Proc., vol. 13, p. 415, 1861. THE LARAMIE PROBLEM. 5 cene “strengthen the impression that this Fort Union lignite group probably represents the Eocene of Europe.” For a number of years succeeding the publi- cation of the last-mentioned paper, or during the years covered by the Civil War, there was little scientific activity in the vast and then almost unknown Western Territories, but in the spring of 1867 Hayden secured an appro- priation from Congress for the geologic inves- tigation of Nebraska. His report on this area ‘° was submitted from the field on July 1,’ 1867. In this he quoted without change the general sections of the Cretaceous and Tertiary rocks of Nebraska, from the paper of 1861, above mentioned. The area supposed to be covered by the ‘Fort Union or Great Lignite group” was greatly extended, occupying not only all the country along the Missouri from Heart River to the Musselshell, most of the valley of the Yellowstone, and northward into the British possessions, but southward as far as the North Platte and ‘‘coming to the surface again at Pikes Peak, Colorado, and extending to Raton Pass, in New Mexico.” The coal near Denver and Golden, in the Denver Basin, as well as what is now known as the Canon City field and thence southward to the Raton Pass dis- trict, was considered to be of Tertiary age, and this view was affirmed the following year.'* In Hayden’s third annual report,” which em- braced Colorado and New Mexico, the area over which the coal-bearing rocks are dis- tributed was greatly extended. “I regard all the coal beds of the West as lower Tertiary”’ (p. 189) is his final word at this time. At this point a brief review may be given of the reasons which up to this time had led Hayden and others to regard the ‘Great Lignite deposits” of the West as of Tertiary age. These beds had been first studied in the upper Missouri River region, where their position above the marine Cretaceous section was plainly marked. Although they were not known to be separated from the marine Cre- taceous by a discordance of any kind, they were obviously above it. The paleontologic evidence, at least so far as concerned the Hayden, F. V., U. S. Geol. Survey Terr. First Ann. Rept., pp. 1-64, 1867; reprint, 1873. 16 Hayden, F. V., Notes on the lignite deposits of the West: Am. Jour. Sci., 2d ser., vol. 45, p. 198, 1868; U. S. Geol. Survey Terr. Second Ann. Rept., 1868; reprint, 1873. 11U. S. Geol. Survey Terr. Third Ann. Rept., 1869; reprint, 1873. 6 LARAMIE: FLORA OF THE DENVER BASIN. vertebrates and invertebrates, had been found somewhat conflicting, though it favored the Tertiary side. It was the fossil plants, of which great numbers were found, that proved of most value in influencing opinion. The material, especially that obtained by Hayden while on the Raynolds expedition of 1859-60, was studied by the well-known paleobotanist J.S. Newberry. Although Newberry’s report was evidently prepared and submitted as early as 1867, it was not published until 1869, when it appeared as an appendix to Hayden’s ac- count. of: the geology.* Newberry argued strongly for the Tertiary (Miocene) age of the “Fort Union or Great Lignite series.” The preliminary paper in which the Fort Union plants were first described by Newberry was published in 1868, though the final publica- tion in which they were fully described and adequately illustrated was not published until 1898.” The fossil plants obtained by Hayden in Colorado and Wyoming in 1867 and 1868 were studied by Leo Lesquereux, and his preliminary report on them was printed in the form of a letter to Hayden.” the Laramie Plains, Wyoming, the Denver Basin of Colorado, andthe Raton Mountains of southern Colorado and northern New Mexico. Lesquereux regarded the plants from all these localities as of Miocene age, a con- clusion which of course confirmed Hayden in his opinion held at that date (1869) that all the coal of the West was of Tertiary age. Up to this time there had apparently been practical unanimity as to the Tertiary age of the lignite series, ‘‘the only varying evidence being found in what Dr. Leidy considered the Wealden type of the Judith River vertebrates.” The first dissenting voice to this general current belief appears to have been raised by John L. Le Conte, who had accompanied an expedition for the survey of an extension of the Union 18 Hayden, F. V., Geological report of the exploration of the Yellow- stone and Missouri rivers, under the direction of Capt. W. F. Raynolds, in 1859-60, 1869. Newberry’s ‘Report on the Cretaceous and Ter- tiary plants” occupies pp. 145-174. 19 Newberry, J. S., Notes on the later extinct floras of North America, with descriptions of some new species of fossil plants from the Cre- taceous and Tertiary strata: New York Lyceum Nat. Hist. Annals. vol. 9, pp. 1-76, 1868. 20 Newberry, J. S., The later extinct floras of North America (a post- humous work, edited by Arthur Hollick): U. 8. Geol. Survey Mon. 35, 1898. 21 Am. Jour. Sci., 2d ser., vol. 45, pp. 205-208, 1868; reprinted in U. 8, Geol. Survey Terr. Third Ann. Rept., pp. 195-197, 1873. They included plants from Pacific Railroad from Smoky Hill River, Kans., to the Rio Grande. The first announcement is an extract from a letter dated Fort Craig, N. Mex., October 3, 1867, published in the American Journal of Science for January, 1868.2 In this letter he stated that he had been enabled to make an examination and determine the age of a bed of anthracite near Old Placer Mountain, 25 miles southwest of Santa Fe, N. Mex.** The data upon which the Cretaceous age was predicated were not given at this time but were set forth in his full report ** published later in 1868. At a num- ber of localities, but notably in the canyon of Purgatoire River and near Trinidad, he found undoubted Cretaceous itivertebrates associated with the coal, and in the higher beds he col- lected plants which Lesquereux pronounced of Tertiary age. Although Le Conte’s paper bears date of February, 1868, it evidently was not published on that date, for in the paper he speaks of having seen Hayden’s article on “Lignite deposits of the West” in the March number of the American Journal of Science for that year. In fact, he devotes several pages (pp. 65-68) to disproving Hayden’s contention that all the coal of the West was of Tertiary age. In addition to studying the rocks of the Raton-Trinidad area, Le Conte made a journey from Trinidad to Denver, noting the coal near Colorado City and in the Denver Basin at Marshall, Golden, and other places. All this coal he considered to be of Cretaceous age, in spite of the evidence for Tertiary age adduced by Hayden and Lesquereux. Without unduly anticipating it may be pointed out that subsequent study in the Raton-Trinidad area has shown that both Le Conte and Lesquereux were right—that is, the beds which yielded the Inoceramus are now known to be separated by marked uncon- formity from those above which supplied most. of the plants studied by Lesquereux.. (See pp. 18-19.) % Cretaceous coal in New Mexico: Am. Jour. Sci., 2d ser., vol. 45, p. 136, 1868. %3 Two years later F. V. Hayden visited this gegion and reported that the coal beds were above Cretaceous rocks containing Ostrea congesta, O larva, Inoceramus, etc. The anthracite he explained as being due to’ the presence of an enormous dike. (See Preliminary field report of the United States geological survey of Colorado and New Mexico [U. 8. Geol. Survey. Terr. Third Ann. Rept.], pp. 66-68, 1869.) % Le Conte, J. L., Notes on the geology of the survey for the extension of the Union Pacific Railway from the Smoky Hill River, Kans., to the Rio Grande, pp. 1-117, 1868. HISTORICAL REVIEW OF In 1869 Cope * published an elaborate paper on American fossil vertebrates in which he laid the foundation at least for a possible reference of certain of the localities of the Missouri River region to the Cretaceous. In discussing Ischyrosaurus antiquus Leidy (p. 40), which came from Moreau River in what is now South Dakota, he said that the horizon may be “ per- haps of Cretaceous age,’ and under Hadro- saurus? occidentalis Leidy (p. 98) he recorded the horizon as ‘“ ? Cretaceous beds of Nebraska, between Moreau and Grand rivers.’’ In the same paper he refers the badlands of the Judith River to the upper Jurassic. About this time the United States Geological Exploration of the Fortieth Parallel, under the direction of Clarence King, had reached that stage of its work which permitted the publica- tion of the first to appear of its final reports.” To this volume King contributed a number of chapters, among them one on the geology of the Green River Basin of Wyoming, in which he held that the coal-bearing strata are of Cretaceous age and are unconformably overlain by fresh-water deposits of Tertiary age. On this point he says (p. 453): Near the summit of the 9,000 feet a looser texture begins, and this change is rendered very noticeable by the intro- duction of beds of coal, which for an unknown distance upward, probably several thousand feet, reappear through a zone of constantly changing sand and mud rocks. The fossil life, which clearly indicates a Cretaceous age for the deepest members up to and including the first two or three important coal beds, from that point gradually changes with a corresponding alternation of sediments, indicating a transition to a fresh-water period. The coal continued to be deposited some time after the marine fauna had been succeeded by fresh-water types. The species of fossils are in no case identical with the Cali- fornia Cretaceous beds, which occupy a similar geological position on the west of the Sierra Nevadas. Their affinities decidedly approach those of the Atlantic slopes, while the fresh-water species, which are found in connection with the uppermost coal beds, seem to belong to the earfy Ter- tiary period. Regarding the unconformable relations of the beds above mentioned to the overlying Tertiary, he said (p. 455): Whatever may be the relation of these beds in other places, it is absolutely certain that within the region lying between the Green River and the Wasatch arid bounded on the south by the Uintah Range there is no single in- 25 Cope, E. D., Synopsis of the extinct Batrachia, Reptilia, and Aves of North America: Am. Philos. Soc. Trans., vol. 14, pp. 1-252, 1869-70. 36 U.S, Geol. Expl. 40th Par. Rept., vol. 3, Mining industry, Wash- |. ington, 1870. THE LARAMIE PROBLEM. 7 stance of conformity between the coal beds and the hori- zontal fresh-water strata above them. This same chapter contains a report by F. B. Meek on the fossil invertebrates of the region, in which he made the following guarded state- ment: With the exception of the genus Inoceramus, which is certainly represented by two or three species, and perhaps Anchura. all of these fossils, so far as their characters can be made out. appear to be just such forms as might be referred with about as much propriety to the Tertiary as to the Cretaceous. In fact. it is probable, from the general absence of characteristic Cretaceous types among them (with the exceptions mentioned) that, if submitted to almost any paleontologist not aware of the fact that the specimens of Inoceramus and Anchura? occurred in the same beds, the whole would be unhésitatingly referred to the Tertiary. * * * From all the facts now known, I can therefore scarcely doubt that you are right jn referring these beds to the Cretaceous. In this report Meek also discussed the age of the so-called ‘‘Bear River Estuary beds,” a series of fresh-water beds contiguous to Bear River in western Wyoming and eastern Utah. A complete historical review of the Bear River controversy, together with an enumeration of its invertebrate fauna, was given by ©. A. White in 1895.77 A brief exposition of this matter will be found on page 78 of this report. The Fourth Annual Report of the Geological Survey of the Territories, for 1870 (published in 1871), was devoted to Wyoming and por- "tions of contiguous territories. In a brief review of the geology of the Missouri River region, which forms Chapter VII of this report (pp. 85-98), Hayden again insisted upon the Tertiary age of the ‘‘Fort Union or Great Lignitic,”’ and in support of this contention quoted from Newberry’s report on the fossil plants as published in the Raynolds report already mentioned. (See p. 6.) That co den had come to realize the possibility that the coals of the West might not all be of Tertiary age is shown by the following remark (p. 94): The area which it [Fort Union] occupies is not yet known, but every year it is extended north, south, and west. It is also characterized by numerous beds of coal, or lignite as it was formerly called, and, so far as the upper Missouri is concerned, most of the coal is true lignite. It is quite probable that the coal-making period began in the later portion of the Cretaceous era and extended up into the Tertiary. The observations of. 21 White, C. A., The Bear River formation and its characteristic fauna: U.S. Geol. Survey Bull. 128, 1895. : ‘ 8 LARAMIE FLORA OF geologists in New Mexico and Utah point to the conclusion that large deposits of excellent coal occur in the upper Cretaceous. In the same report (p. 165) in discussing conditions on the Laramie Plains, he said: That there is a connection between all the coal beds of the West I firmly believe, and I am convinced that in due time that relation will be worked out and the links in the chain of evidence joined together. That some of the older beds may be of upper Cretaceous age I am prepared to believe, yet until much clearer light is thrown upon their origin than any we have yet secured I shall regard them as belonging to my transition series or beds of passage between the true Cretaceous and the Tertiary. Lesquereux also contributed a short paper to this same report in which (pp. 381-385) he gave a list of all the supposed Tertiary plants of the negion known at that date. This list includes 30 species from the “Ko-lignitic” (now Wilcox formation) of Mississippi, 8 species from the Raton Pass region (now Raton formation) of New Mexico and Colo- rado, 9 species from Marshall, Colo. (now Laramie formation), 2 species from Golden, Colo. (now Denver formation), and 6 species from Rock Creek, Laramie Plains, Wyo. (now ‘“‘ Upper Laramie’’).”8 In the Fifth Annual Report of the U. S. Geological Survey of the Territories, for 1871, which was published in 1872, Lesquereux has a long report on new plants from localities in Wyoming and Montana, all of which he con- sidered to be of Tertiary age. He also attempted an important generalization in dividing the several localities among the stages of the Tertiary. This may be sum- marized as follows: To the Eocene he referred the localities of Mississippi (‘‘Eo-lignitic”); of Raton Pass, Purgatoire Canyon, and Marshall mine, near Denver, Col.; of Washakie Station, Evanston both above and below the coal, and Snake River just below [south off the Yellowstone Park, all in Wyoming; and 6 miles above Spring Canyon, Mont. To the lower Miocene he referred the Fort Union and Yellowstone, Mont.; Rock Creek, Medicine Bow, Junction Station, and Carbon Station, Wyo.; to the middle Miocene Henrys Fork, Muddy Creek, and Barrell’s Springs, Wyo., and Elko Station, Nev. The following localities were not at this 23 With the exception of that at the Marshall locality, all the collections above enumerated as Tertiary by Lesquereux are accepted as such at the present day, though for some of them it has required 40 years to establish the truth of Lesquereux’s assignment. \ THE DENVER BASIN. time definitely placed stratigraphically: Green River, Point of Rocks, Sage Creek, and mouth of Spring Canyon. In the following year (1872) Lesquereux | himself spent several months in the study of this general field, undertaken at the direction of Hayden, as he somewhat naively remarks, with the “view of positively ascertaining the age of the lignite formations, either from data obtainable in collecting and examining fossil vegetable remains, or from any geological observations which I should be able to make.” During this investigation Lesquereux visited and collected from the coal fields of Marshall and Golden in the Denver Basin, Colorado Springs, Canon City, Trinidad, and Raton, and also along the line of the Union Pacific Railroad from Cheyenne to Evanston, Wyo. His re- sults ?° were considered as confirmatory of his previous conclusions, namely, that the beds at these localities are of Tertiary age and con- stitute what he called the American Eocene The same year Meek and Bannister, who were also conducting investigations along the line of the Union Pacific Railroad, made a dis- covery at Black, Buttes which, in the opinion of many, had a very definite bearing on the age of the coal of the region. This was the finding of the remains of a huge dinosaur which was named by Cope * Agathaumas sylvestris. In his paper Cope said: From the above description it is evident that the animal of Black Buttes is a dinosaurian reptile. * * * Itis thus conclusively proven that the coal strata of the Bitter Creek basin of Wyoming Territory, which embraces the greater area yet discovered, were deposited during the Cretaceous period, and not during the Tertiary, though not long preceding the latter. In a short paper published later in the same year Cope,*! in commenting on the discovery of Agathaumas, said: ‘This discovery places this group [the so-called Bitter Creek series] without doubt within the limits of the Cretaceous period, and to that age we must now refer the great coal area of Wyoming.” In commenting on the age of the “Bitter Creek series,’ as the beds at Black Buttes and vicinity were then designated, Meek*® ex- pressed himself with extreme caution, saying: 29 Lesquereux, Leo, Lignitic formations and fossil flora: U. S. Geol. Survey Terr. Sixth Ann. Rept., for 1872, pp. 317-427, 1873. 20 Cope, E. D., On the existence of Dinosauria in the transition beds of Wyoming: Am. Philos. Soc. Proc., vol. 12, p. 481, 1872. 31 Cope, E. D., The geological age of the coal of Wyoming: Am. Natu- talist, vol. 6, p. 669, 1872. 32 Meek, F. B., U. S. Geol. Survey Terr. Sixth Ann. Rept., for 1872, Pp. 458, 461, 1873. t i" HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 9 The reptilian remains found at Black Butte, near the top of the series, have, as elsewhere stated, been investi- gated by Prof. Cope and by him pronounced to be de- cidedly dinosaurian and therefore indicative of Cretaceous age. On the other hand, the fossil plants from the same beds have been studied by Prof. Lesquereux, who informs me that they are unquestionably Tertiary types. My own investigations having been confined to the invertebrates, it is of these chiefly that I will speak here. In the first place, it will be seen that all of these yet known belong to a few genera of mollusks, represented by 12 or 14 species. And just here it may be stated that, although partly com- mitted in favor of the opinion that this formatiqn belongs to the Cretaceous and still provisionally viewing it as most probably such, I do not wish to disguise or conceal the fact that the evidence favoring this conclusion to be de- rived from the mollusks: alone, as now known, is by no means strong or convincing. The genera are probably all common both to the Cretaceous and Tertiary, as well as to the present epoch. * * * The entire absence among the fossils yet known from this formation of Bacu- lites, Scaphites, Ancyloceras, Phychoceras, Ammonites, Gy- rodes, Inoceramus, and all of the other long list of genera characteristic of the Cretaceous or in part also extending into older rocks, certainly leaves its molluscan fauna with a strong Tertiary facies. * * * It thus becomes mani- fest that the paleontological evidence bearing on the ques- tion of the age of this formation, so far as yet known, is of a very conflicting nature; though aside from the dino- saurian, the organic remains favor the conclusion that it is Tertiary. It is plain that Meek was very much con- fused by the data then available, especially by the invertebrates, for he declared in another place that they might with almost equal pro- priety be referred to the Tertiary or the Cre- taceous, and as the vertebrate evidence was interpreted to mean. undoubted Cretaceous, only the fossil plants were left to sustain un- falteringly the Tertiary side of the argument. It was immediately pointed out, as it is oc- casionally even to the present day, that the error made by Oswald Heer in referring plants of the Dakota “group” to the Miocene * weakened the evidence of fossil plants and gave added weight to the dictum of the vertebrate paleontologist, namely, that the presence of dinosaurian reptiles in a formation was positive proof of Cretaceous age. Thus Cope was so firmly convinced that the presence of Agathau- % Those who are interested in this reference of the Dakota sandstone to the Miocene may beinstructed by reading Lesquereux’s account of the conditions under which the error was made (U. S. Geol. Survey Terr. Sixth Ann. Rept., for 1872, p. 343, 1873). From this account it appears that Heer never saw specimens of the Dakota plants, for only outline drawings of a few species were submitted to him. They were mostly dicotyledonous leaves and wholly unlike any then (1857) known from the Cretaceous of Europe, and the drawings were without the essential details of nervation. As soon as the specimens themselves were seen by Newberry he recognized their correct characters. mas at Black Buttes proved the Cretaceous age of the ‘‘Bitter Creek series” that in 1874 he proceeded to refer the “Great Lignitic” of the upper Missouri to the same period. In discussing the age of certain vertebrate- bearing beds in northern Colorado, he said: * ‘Believing, as I do, that’ the evidence derived from the vertebrate remains requires the reference of the Bitter Creek coal series to the Cretaceous period; and having pointed out on similar grounds that the horizon of the Great Lignite from which vertebrate remains have been procured on the Missouri River is undoubtedly Mesozoic, although usually regarded as Tertiary, I suspect that the corre- sponding strata in Colorado will be found to pertain to the same section of geologic time. In another bulletin of *this series Cope * had an extensive article on the fossil verte- brates then recognized from the Cretaceous of the West. In this paper vertebrates from the localities on Moreau River and between Moreau and Grand rivers, S. Dak.; at Long Lake, N. Dak.; north of Big Horn River, Mont.; and in Colorado, now mainly referred to the Lance formation, he for the first time definitely referred to the Cretaceous. In alluding to the studies-of the flora of these beds by Les- quereux and Newberry, he said (p. 16): They have, as is well known, pronounced this whole series of formations as of Tertiary age, and some of the beds to be as high as Miocene. The material on which this determination is based is abundant, and the latter must be accepted as demonstrated beyond all doubt. I regard’ the evidence derived from the mollusks in the lower beds, the vertebrates in the higher, as equally conclusive that the beds are of Cretaceous age. There is, then, no alter- native but to accept the result, that a Tertiary flora was contemporaneous with a Cretaceous fauna, establishing an uninterrupted succession of life across what is generally regarded as one of the greatest breaks in geologic time. The above statement by Cope has often been quoted during the 48 years since it was written, and it is only recently that its converse—that ‘is, that a fauna of Cretaceous type may be contemporaneous with a Tertiary flora—has been admitted as even possible. This conclusion was further elaborated by Cope in Hayden’s annual report for 1873, in a paper that was more or less in the nature of a reply to the article by Newberry already men- % Cope, E. D., Report on the stratigraphy and Pliocene vertebrate paleontology of northern Colorado: U. 8. Geol. and Geog. Survey Terr. Bull. [1st ser.], No. 1, p. 10, 1874. 35 Cope, E. D., Review of the Vertebrata of the Cretaceous period found west of the Mississippi River: U. 8. Geol. and Geog. Survey Terr. Bull. [Ist ser.], No. 2, pp. 1-51, 1874. 10 tioned. In the same report Marvine * had an elaborate paper on the results of his studies in Middle Park, Colo., in which he considered among many other things, the age of the lignite-bearing formations of Colorado. After alluding to the weakness of ‘the invertebrate evidence for the Cretaceous age and the ap- parent strength of the evidence derived from the terrestrial vertebrates, he said: It must be supposed, then, that either a Cretaceous fauna extended forward into the Eocene period and existed contemporaneously with an Eocene flora, or else that a flora, wonderfully prophetic of Eocene times, antic- ipated its age and flourished in the Cretaceous period to the exclusion of all Cretaceous plant forms. * * * In either case the fact retfiains that here the physical and other conditions were such that one of the great kingdoms of life, in its progress of development, either lost or gained upon the other, thus destroying relations and associations which existed between them in those regions from which were derived the first ideas of life boundaries of geologic time, causing here apparent anomalies. As a probable explanation of these apparent discrepancies, Marvine wisely concludes as follows: ‘Much of the confusion and discrep- ancy has, in my opinion, arisen from regarding different horizons as one and the same thing.” In his report for 1873 Lesquereux had a further paper on the “Lignitic” flora in which he of course argued still more strongly for its Tertiary age. ‘He also revised the several ‘“‘sroups”’ into which he divided the section of lignite-bearing rocks and presented full lists of the species of plants found in each. In Hayden’s original description of the Fort Union formation he predicted that it would be found extending into Canadian territory, and this prediction was verified in 1874 by George M. Dawson,*’ who published an article in which he accepted the views of Hayden and Les- quereux and referred the Fort Union to the Eocene. In discussing the views of Cope he said: ‘ The evidence does not appear to show that the Creta- ceous species were of themselves becoming rapidly extinct, but that over the western region, now forming part of this continent, the physical conditions changing drove the Cretaceous marine animals to other regions, and it-is im- possible at present to tell how long they may have en- dured in oceanic areas in other parts of the world. This being so, and in view of the evidence of the preponderant animal and vegetable forms, it seems reasonable to take LARAMIE FLORA OF THE DENVER BASIN. the well-marked base of the Lignite series as that of the lowest Tertiary, at least at present. The formation de- ‘scribed belongs to this lowest Tertiary, being, in fact, an extension of Hayden’s Fort Union group, and from analogy may be called Eocene. =, The work upon which Dawson’s views were based was done in connection with the British North American Boundary Commission, of which he was geologist. In a report of progress for 1873, published in 1874, he affirmed his original statement in the following language:”*. The formation is, however, undoubtedly an extension of the Great Lignite or Fort Union group of strata of ‘Hayden, as developed in the Western States and Terri- tories. * * * These strata immediately succeeding the Cretaceous rocks are the lowest American representa- tives of the Tertiary series and have been called, for this reason, Eocene. In the final report of the Boundary Commis- ‘sion, published in 1875, the same views were expressed. About this time John J. Stevenson, who was then associated with the Wheeler Survey, published a number of papers on the geology of portions of Colorado and New, Mexico in which he argued strongly for the Cretaceous age of the lignite-bearing beds, especially along the Front Range. In a chapter on the age of | the Colorado lignites*® he reviewed the opinions of Hayden, Lesquereux, and others and con- ‘cluded that the presence of the supposed fucoid Halymenites major was an indication of Cretaceous rather than Eocene age, as advocated by Lesquereux. Subsequent study has shown that Stevenson was correct in referring the beds containing Halymenites to | the Upper Cretaceous, but he failed to note | the presence, of the profound unconformity that has since been demonstrated by Whitman Cross and W. T. Lee to occur in the midst of this supposedly continuous coal-bearing section. In the annual report of the Hayden Survey for 1874, published in 1876, there are three very important papers dealing more or less com- pletely with this subject. The first of these is one by Hayden, in which he summed up his understanding of the lignite group at that date. He gave a brief history of the group and pointed out that the evidence for its age, as interpreted by different geologists and paleon- tologists, is very conflicting. He said: 36 Marvine, A. R., Report of the Middle Park division: U. S. Geol, and Geog. Survey Terr. Ann. Rept. for 1873, p. 107, 1874. 31 Dawson, G. M., The Lignite formations of the West: Canadian Naturalist, vol. 7, p. 241, 1874. 88 Dawson, G. M., Report on the Tertiary Lignite formation in the vicinity of the 49th parallel, British North Am. Boundary Com., 1874. 89U. S. Geog. and Geol. Surveys W. 100th Mer. Rept., vol. 3, pp. 404-410, 1875. HISTORICAL REVIEW OF One fruitful source of difference of opinion has been in the misunderstanding in regard to the different horizons of coal strata of the West. That there are important coal beds in rocks of well-defined Cretaceous age can not be disputed, and I have long since yielded that point. What we wish to show more clearly is that there exists in the West a distinct series of strata which we have called the Lignite grouj, and that it is entirely separate, paleon- tologically and geologically, from a great group of strata in the lower Cretaceous, and perhaps extending down into the Jurassic, which contains a great number of thick and valuable beds of coal. It is not necessary to discuss the question whether the term Lignitic shall be applied to the coal of either or both groups. I have used the term Lignitic for the upper group without reference to the quality of its fuel, simply to distinguish it from the other great groups of older date, the ages of which are not questioned. From the above statement it is clear that Hayden was entirely willing to admit the exist- ence of coal in the Cretaceous of the Rocky Mountain region, and from ,this it of course followed that the term “Lignitic” was not ap- plicable to all the coal-bearing strata; in fact, he distinctly stated that the term was to be applied only to the upper coal-bearing series. He still argued, however, for the connection of the coal-bearing beds of the Laramie Plains and Colorado with the vast group to the northwest. The same report contained a long paper by A. C. Peale on the geology of. portions of Colorado, in which he presented a series of tables illustrating the progress of opinion regarding the ‘“Lignitic group.” He dis- cussed the different opinions at length and reached the following conclusions: 1. The lignite-bearing beds east of the mountains in Colorado are the equivalent of the Fort Union group of the upper Missouri and are Eocene Tertiary; also, that the lower part of the group, at least at the locality 200 miles east of the mountains, is the equivalent of a part of the lignitic strata of Wyoming. 2. The Judith River beds have their equivalent along the eastern edge of the mountains below the Lignite or Fort Union group and also in Wyoming and are Cretaceous, although of a higher horizon than the coal-bearing strata of Coalvilleand Bear River, Utah. They form either the “upper part of the Fox Hills group (No. 5) or a group to be called No. 6. Also in this report for 1873 Lesquereux had ' an extensive paper under the title “On the Tertiary flora of the North American Lignitic, considered as evidence of the age of the for- mation.” He again took up the objections that. had been urged against his interpretation and - | they studied were of Cretaceous age. THE LARAMIE PROBLEM. 11 answered each in detail as the evidence appeared to him. His opinion remained unchanged. ‘The historical review of opinion which pre- ceded the introduction of the term Laramie has now been presented in sufficient detail to make clear the necessity for a convenient, usable, common appellation. Those who had ap- proached the subject from a study of the northern areas—that is, of the upper Missouri River region and contiguous territory—were naturally impressed with the strength of the argument for the Tertiary age of the lignite- bearing beds, while those who had first become familiar with the more southern areas were quite as strongly of the opinion that the beds Sub- sequent study has shown that both these views contained a measure of truth. As A. C. Peale was at that time actively en- gaged in geologic work in the Rocky Mountain area, his recollection of the conditions then current, as set forth in a recent article,” is of interest: As a member of the Hayden Geological Survey at the time the term “Laramie” was first proposed and used by both the Hayden and King organizations, and as one of those who first used it, a statement of my recollection may be of some interest here. Just at the time the work of the Exploration of the Fortieth Parallel, under Clarence King, was approaching completion, and their geologic maps were being colored, the work of the United States ‘Geological and Geographical Survey of the Territories had also reached the stage when it became necessary to color the maps of Colorado, upon which field work was begun in 1873 and finished in 1876. As two of the maps of the former organization adjoined the work of the Hayden Survey along the northern line of Colorado, it was deemed desirable that there should be some cortdlation, in terms at least, where the work joined. There was substantial agreement as to most of the formations, about the only difference being as to the age of the beds resting con- formably upon the Fox Hills Cretaceous of Hayden as exposed along the line of the Union Pacific Railway and to the westward of the foothills of the Front Range. of Colorado, where they were usually designated by Hayden and the members of his Survey as the Lignitic beds of eastern Colorado or the lignitic coal group of the eastern slope. These beds were considered by King-to be of Cretaceous age, while Hayden was inclined to consider them as belonging to the Tertiary. At this time Clarence King wrote to Dr. Hayden asking him to propose a name for these debatable beds—debatable only as to age, for both agreed as to their stratigraphic position. In reply to this letter Hayden suggested the name Laramie, which was accepted by King, as indicated by him on page 331 40 Peale, A. C., On the application of the term Laramie: Am. Jour. nay 4th ser., vol. 27, p. 45, July, 1909. 12 of the volume on systematic geology,*! where he says: “During the slow gathering of the evidence which shail finally turn the scale I proposed to Dr. Hayden that we adopt a common name for the group and that each should refer it to whatever age his data directed. Accordingly, it was amicably agreed between us that this series should receive the group name of Laramie and that it should be held to include that series of beds which conformably overlies the Fox Hills.” It may be of interest to point out that, so far as now known, the word Laramie used as a geologic formational term first appeared in an author’s proof of geologic map No. II of the Fortieth Parallel Survey, by Clarence King and S. F. Emmons. This map was dated November 15, 1875, and was noticed in the American Journal of Science for February, 1876, but in‘neither place was there any definition of the term. The first printed description of the Laramie was apparently that given by Arnold Hague ® in volume 2 of the final reports of the Fortieth Parallel Survey, in which he presented a very small and rela- tively unimportant section that claims dis- tinction only on the ground that it was the first section ever published .of the Laramie. It was measured on the Denver Pacific Rail- road 5 or 6 miles west of Carr station and about 18 miles southeast of Cheyenne, Wyo. Peale “ stated that ‘this section, if any should be so considered, would be the typical Laramie section.” Hayden first used the term Laramie in an article published in 1877. In this article he followed the coloring on King’s map above mentioned, which he undoubtedly had before him at the time. King and the members of his Survey frankly and, as he says, “cheerfully” adopted the classification and nomenclature of the Upper Cretaceous section as defined by Hayden. After describing the Cretaceous rocks of their area up to and including the Fox Hills, King said :* Here, with those who follow Hayden, the Cretaceous series comes to an end. Conformably over this (Fox Hill) lies the group which Hayden and I have agreed to call the Laramie, which is his Lignitic group and is considered by him as a transition member, between Cretaceous and 4. U. 8. Geol. Expl. 40th Par. Rept., vol. 1, 1878. 42 Idem, vol. 2, pp. 60, 61, 1877. 43 Am, Jour. Sci., 4th ser., vol. 27, p. 49, 1909. 44 Notes on some artesian borings along the line of the Union Pacific Railroad in Wyoming Territory: U. S. Geol. and Geog. Survey Terr, Bull., vol. 3, pp. 181-185, April 5, 1877. 4 U, S. Geol. Expl. 40th Par. Rept., vol. 1, p. 348, 1878. LARAMIE FLORA OF THE DENVER BASIN. Tertiary. There is no difference between us as to the conformity of the Laramie. group with the underlying Fox Hill. Itissimply a question of determination of age upon which we differ. King was in error, however, in stating that the Laramie was the equivalent of Hayden’s Fort Union “group,” or indeed that it included all of the so-called Lignitic, and it was un- doubtedly the assumption by subsequent writers that this was so that led to much of the discussion and difference of opinion that speedily arose. Hayden’s last published word on this point “ occurs in the letter transmitting Lesquereux’s “Tertiary flora” to the Secre- tary of the Interior and is as follows: If objection is made to the use of the term ‘‘Lignitic” group, I would say that in this work it is restricted to a series of coal-bearing strata lying above the Fox Hills group, or Upper Cretaceous, and these are embraced in the divisions Laramie and Fort Union groups. It is well known that there are in various parts of the West, espe- cially along the fortieth parallel and southwestward, very thick beds of coal in the various divisions of the Cre- taceous, extending down even into the upper Jurassic. - Had this not been the case, the more general term Lignitic would not have been retained by the Survey in preference to any other. On the succeeding page of this letter he summed up his conclusion in the following words: The facts as we understand them at the present time would seem to warrant this general division, viz, a marine series, Cretaceous; gradually passing up into a brackish- water series, Laramie; gradually passing up into a purely fresh-water series, Wasatch. It is also probable that the brackish-water beds on the upper Missouri must be corre- lated with the Laramie, and that the Wasatch group as now defined and the Fort Union group are identical as a whole, or in part at least. The Laramie was by that time fairly launched, and the literature devoted to it be- came increasingly voluminous and scattered. It is not possible nor perhaps desirable in the present connection to follow all the intricate ramifications of the discussion, and only an outline of the salient features will be attempted. The two points that attracted most attention were the areal distribution of the Laramie and of course its age. As so frequently happens in discussions of this kind, the pendulum when once started was permitted to swing too far, with the result that beds were included in the Laramie ‘that subsequent study has proved have little or no intimate connection with 4© U.S. Geol. Survey Terr. Rept., vol. 7, p. iv, 1878. HISTORICAL REVIEW OF ' this formation, at least on the basis of the original definition by King. Some phases of this history will be set forth in the following pages. One of the first to take up the study of the Laramie from both the geologic and the pale- ontologic sides was Charles A. White. In the first paper in which he employed the term | Laramie “’ the use was relatively unimportant generalized sections—one of the Green River region, in which he placed the Laramie in its proper position between the Fox Hills and the Wasatch beds, and within the larger grouping of post-Cretaceous, which also includes the lower part of the Wasatch; and the other of the upper Missouri River region, in which the Laramie was not included but its place was taken by the Judith River ‘‘group,” while the post-Cretaceous was made. to include this and a portion of the overlying Fort Union. White’s reasons for regarding the Laramie as post-Cretaceous were set forth in the fifth of his ‘‘Paleontological papers” “ published in the same volume as the paper just cited. He said that all who had examined the fossils from the Dakota, Colorado, and Fox Hills deposits as- they are developed in southern Wyoming and adjacent parts of Utah and Colorado, whether : vertebrate or invertebrate, would not question. their Cretaceous age. The fossils of the Green River and Bridger strata were said to disclose’ equally conclusive evidence of their Tertiary age. He went on to say that the two groups of beds between the Fox Hills below and the Green River above are the Laramie and Wasatch, and that somewhere within these. vertical limits must come the line between Cretaceous and Tertiary. He then continued:: With a few doubtful exceptions, none of the strata of the Laramie group were deposited in open-sea waters; and with equally few exceptions, none have yet furnished | invertebrate fossils that indicate the Cretaceous rather than the Tertiary age of the group. * * * Again, the. brackish and fresh water types of Mollusca that are afforded by the Laramie and the lower portions of the Wasatch group are in most cases remarkably similar, and some of the species of each group respectively approach each other so nearly in their characteristics that it is often’ 47 Catalogue: of the invertebrate fossils hitherto published from the fresh and brackish water deposits of the western portion of North America: U.S. Geol. and Geog. Survey Terr. Bull., vol. 3, pp. 607-614, May 15, 1877. 48 Idem, pp. 625-629. 85344—22—2 THE LARAMIE PROBLEM, 13 difficult to say in what respect they materially differ. Moreover, they give the same uncertain indication as to their geological age that all fossils of fresh and brackish water origin are known to do. It is in view of the facts here stated, and also because I believe that a proper interpretation of them shows the strata of the Laramie group and the base of the Wasatch to be of later date than any others that have hitherto been referred to the Cretaceous, and also earlier than the Eocene epoch, that I have decided to designate those | strata as post-Cretaceous, at least provisionally. — and the term was not defined. He gave two | In the annual report of the Hayden Survey for 1876, published in 1878, White presented in a lengthy paper the results of his field studies in Colorado for the years 1876 and 1877. He still retained the term post-Cre- taceous for the Laramie and in an instruc- tive table (p. 22) showed that he regarded it as the equivalent of the Laramie of King, the Point of Rocks group of Powell, and the Lignitic of Hayden. He defined it’ as follows: The fact that this series passes insensibly into the Fox Hills group below and into the Wasatch group above renders it difficult to fix upon a stratigraphical plane of demarcation, either for its base or summit. I have there- fore decided to regard this group as essentially a brackish- water one, referring all’ strata below that contain any marine Cretaceous invertebrate forms to the Fox Hills group, beginning this series with those strata that con- contain brackish and fresh water forms, and ending it above with those strata in which the brackish-water forms finally cease. Thus defined, the whole series seems to form one natural paleontological group, as well as to be a sufficiently distinct stratigraphical one, for which I - have adopted the name of Laramie group of King. The term post-Cretaceous was also employed by Endlich * in his report on the White River area of Colorado, and by Peale © in his work in the Grand (now Colorado) River region. The application of the term Laramie was carried farther and farther afield, until ulti- mately it was made to include a vast area in the Rocky Mountain region. When the term was first proposed by King no type locality was mentioned but it was expressly stated to include the lignite-bearing beds lying con- formably above the Fox Hills along the Front Range in northern Colorado and along the west side of the range in eastern and central Wyoming. The term was immediately accepted, though with reservations as to the age represented, by the members of the Hayden 49U. S. Geol. and Geog. Survey Terr. Tenth Ann. Rept., for 1876, pp. 77, 109, 1878. 5 Tdem, p. 181. 14 Survey, who extended its application to west- ern Colorado and adjacent areas. After the death of Meek the mantle of invertebrate pale- ontologic work fell largely upon the shoulders of C. A. White, and he had a large part in extend- ing the application of the Laramie. In the seventh of his ‘‘ Paleontological papers ’’* he gave the following range for Laramie as he then accepted it: : The term Laramie group is here used to include all the strata between the Fox Hills group of the Cretaceous period beneath and the Wasatch group (=Vermillion Creek group of King) of the Tertiary above. That is, it includes, as either subordinate groups or regional divisions, both the Judith River and Fort Union series of the upper Missouri River; the Lignitic series east of the Rocky Mountains in Colorado; the Bitter Creek series of southern Wyoming and the adjacent parts of Colorado; and also the ‘‘Bear River Estuary beds,’’ together with the Evan- ston coal series, of the valley of Bear River and adjacent parts of Utah. Strata of this great Laramie group are known to exist in other large and widely separated dis- tricts of the western portion of the national domain. Later the Laramie was believed by White to have been recognized as far south as the States of Chihuahua, Coahuila, and Nuevo Leon, in northern Mexico. It was also adopted by the Canadian geologists and shown by them to extend over a vast area in the British posses- sions. In fact, as late as 1891, after a number of important horizons had been removed from the confines of the Laramie, White * gave the following as the recognized distribution of the formation: The present geographical outlines of the area within which strata of this formation occur are not yet well known, but it apparently is as great as that within which any other North American formation has been observed. Their presence has been recognized at s0 many and such widely separated localities that they safely may be assumed to once have formed a continuous deposit from near the twenty-sixth to near the fifty-fifth parallel of north latitude and in certain districts from near the one hundred and third to near the one hundred and fifteenth meridian. That is, it is evident that this formation originally con- sisted of a continuous deposit nearly or quite 2,000 miles long from north to south, and more than 500 miles across from east to west. The, structural and lithologic character of the Laramie as it was then (1891) accepted was well set forth by White,** who wrote as follows: §1 White, C. A., On the distribution of molluscan speciesin the Laramie group: U. 8. Geol. and Geog. Survey Terr. Bull., vol. 4, No. 3, p. 721, July 29, 1878, 62 White, C. A., Correlation papers—Cretaceous: U. S. Geol. Survey Bull. 82, p. 145, 1891. 63 Idem, p. 146. ; LARAMIE FLORA OF THE DENVER BASIN. In lithological character the Laramie formation is re- markably uniform throughout both its geographical and vertical extent, and it seems everywhere to have been the result of continuous sedimentation from base to top. Its strata within the whole of the great area which they occupy are mostly composed of sandy material, but frequently they are more or less argillaceous and rarely calcareous. Sandstones of much firmness often occur among them, but a large part of the sandy strata are soft and friable. Shaly strata not infrequently occur, and these are often carbona- ceous. The formation throughout its whole extent is coal- bearing. The question concerning the Laramie which gave rise to the most extensive discussion and difference of opinion was, of course, that of its age. It may be of interest to present a brief recapitulation of the divergent views on this point that had been promulgated up to about 1890, or approximately to the time when, if it is permissible to use the expression, the reac- tion set in, and the pendulum began its back- ward swing as regards what should or should not be includéd within the limits of this forma- tion—the point that subsequent investigation has shown is the cause of much of this differ- ence of opinion. King and the other members of the Fortieth Parallel Survey regarded the Laramie as of Cretaceous age and the ‘equivalent of the Lignitic group of Hayden. ‘The term was immediately accepted by Hayden and the members of the Survey under his direction, though not wholly as a substitute for the earlier ‘‘Lignitic,”’ for they admitted un- doubted Cretaceous coals. Hayden regarded the Laramie as transitional between Cretaceous and Tertiary. Endlich, from his studies in the vicinity of Trinidad, Colo., referred the coal- bearing rocks of the region (=Laramie) to post-Cretaceous or pre-Tertiary. White, End- lich, and Peale, who investigated the Laramie, especially in Utah, Wyoming, and Colorado, called it post-Cretaceous, and White in partic- ular stated his belief that it was transitional between Cretaceous and Tertiary. Stevenson and Newberry also were familiar with the areas in southern Colorado and New Mexico and were firm in their belief that it was Cretaceous. The vertebrate paleontologists Cope, Marsh, and many others after them referred the Lara- mie unqualifiedly to the Cretaceous, largely on the ground that it contained remains of dino- saurian reptiles that were believed to be an unfailing mark of Cretaceous age. On the other hand, Lesquereux, from his extensive HISTORICAL REVIEW OF studies of the fossil plants, was strenuous in his claim that the “Lignitic” and later the Lara- mie were of Tertiary age. In 1884-85 Lester F, Ward ™ instituted an elaborate investigation and comparison of the fossil plants, in the hope of throwing conclu- sive light on its age. Ward was undoubtedly influenced by the prevailing opinion, chiefly that of White, as to what should be regarded as Laramie, with the result, as is now known, of referring to it beds later proved to belong to the Montana, Laramie, Arapahoe, Denver, Lance, and Fort Union, and it is small wonder that he was unable to reach definite conclu- sions. From this point on it will be inexpedient to follow ‘the strictly chronologic method of treatment, for the reason that the literature is so very extensive and scattered, and conse- quently it will be taken up by regions or special horizons that have, for one reason or another, come into prominence. Each of these, particularly those of special interest as bearing on the problem, will be followed through to the present time. It is to be remembered that the area over which the Laramie was believed to be more or less continuously exposed reached its maximum extension about 1890, since when, by a process of elimination or |. subtraction, it has constantly been diminishing until at the present time only a comparatively small area remains to support the name. RELATIONS BETWEEN THE LARAMIE OF THE DENVER BASIN, TAKEN AS A STANDARD, AND THE REPORTED LARAMIE IN THAT ve OTHER AREAS. As set forth in the preceding pages, the his- tory of the Laramie formation shows that it has had what may be called a rise and fall. From the date of the introduction of the term into geologic literature and usage, in 1875, to about 1890 its application was undergoing a: process of expansion, until the formation was believed to have covered a vast area extending. from northern Mexico to the Arctic Circle and many hundreds of milesin width. In part con- current with this expansion, or from about 1888 to the present time, the application of the term has been subjected to a process of elimination. or curtailment, until, as was long ago so aptly & Ward, L. F., Synopsis of the flora of the Laramie group: U. S. Geol. Survey Sixth Ann, Rept., for 1884-85, pp. 401-557, 1886. THE LARAMIE PROBLEM. 15 stated, the problem became not so much “To what age does the Laramie belong?” as “ 4 hat belongs to the Laramie?” As time went on, it was again and again in- contestably shown that beds supposed to ful- fill the requirements of the definition of the Laramie had been incorrectly so placed for one reason or another, and reasonable doubt had been cast upon the right of many other beds to be considered as typical Laramie. It is proposed in the following pages to re- view the several stratigraphic units or geo- graphic areas to which or within which the term Laramie is no longer considered applic- able or at least requires a greater or less meas- ure of qualification. So far as possible the ‘sequence is chronologic, but naturally it has not been expedient to adhere strictly to the chronologic order, so far as that would lead to needless repetition or to the breaking up of the discussion of a natural geographic unit. Never- theless, it has been impossible to avoid some repetition and overlapping in the treatment, owing to the fact that results obtained in one field may have a more or less important bearing on another field. ARAPAHOE AND DENVER FORMATIONS. The area about the city of Denver, Colo., now well known as the Denver Basin, is in a way Classic ground for geology. It had been visited and studied in greater or less detail by a number of geologists and paleontologists, including J. L. LeConte, F. V. Hayden, Leo Lesquereux, A. R. Marvine, C. A. White, S. F. Emmons, Whitman Cross, G. H. Eldridge, and L. F. Ward. The coal-bearing rocks conform- ably above the marine Cretaceous Fox Hills formation were at first believed to be a southern extension of the “ Lignitic group”’ of the upper Missouri River region and were held by Hayden, Lesquereux, and others to be of Tertiary age. When the Laramie “group”’ was estab- lished by King, this portion of the section in the Denver Basin and adjacent areas along the Front Range fell within its limits, and the beds were regarded by him and by those who accepted his views as Cretaceous. This so- called Laramie was for many years regarded as a unit, notwithstanding the fact that at certain points along the base of the moun- tains, notably at Golden, the lower or coal- bearing portion of the section was vertical, 16 whereas the adjacent beds of Table Mountain were practically horizontal. Some geologists invoked the presence of a hypothetical fault to account for this obvious discordance, but it is now known to be due to a sharp fold and not to a fault. This is shown by the fact that at Green Mountain, 3 or 4 miles south of Golden, the Arapahoe and the lower part of the Denver, as well as the Laramie, are verti- cal. Both the lower and the upper beds are abundantly plant-bearing, and both had fur- nished extensive collections, but, as it later ap- peared, no distinction was made in the speci- mens or in the records concerning them, all being called simply ‘‘ Laramie,’’ with the result that when the horizons were proved to be dis- tinct, the greatest confusion and difficulty arose in the effort to separate them. As early as the summer of 1881, when Whit- man Cross * began his studies in the Denver ‘Basin, he “first observed,’’ to use hig own language, “that the Table Mountain strata possessed characteristics proving them to be- long to.a series distinct from the normal Lara- mie.’’ No published announcement of this discovery was made at the time, and field work was continued in the region for a number of succeeding years, during which G. H. Eld- ridge ascertained that another distinct Tertiary formation occurred between that discovered by Cross and the normal Laramie. A preliminary statement of the most important results of this investigation was made by Eldridge and Cross in two papers read before the Colorado Scien- tific Society July 2, 1888. In the first of these papers®* Eldridge named and described the Arapahoe formation,” which, he stated, was “the formation next succeeding the Laramie in. geological order and unconformably resting on it.’’ It was characterized as follows: It is composed of a basal member of conglomerate or’ gritty sandstone, according to its distance from the foot- hills, with an overlying zone of gray argillaceous or arenaceous shales, containing lenticular masses of hard, quartzose sandstone, with an occasional ironstone; when confined between under- and overlying groups it has a thickness varying between 600 and 1,200 feet. 6 Cross, Whitman, The Tertiary Denver formation: Am. Jour. Sci., 3d ser., vol. 37, p. 262, 1889, 66 Eldridge, G. H., On some stratigraphical and structural features of the country.about Denver, Colo.: Colorado Sci. Soc. Proc., vol. 3, pp. 86-118, 1888. 87 This was first named the “ Willow Creek beds,’’ but on the ground of preoccupation the name was changed in a footnote (p. 97) to Arapahoe. LARAMIE FLORA OF THE DENVER BASIN. In the succeeding paper Cross * named and described the Denver Tertiary formation, which he found to be unconformably overlying the Arapahoe. Lithologically it was found to be composed almost entirely of andesitic volcanic material; its thickness was given as 800 to 1,200 feet. As already indicated, both Arapahoe and Den- ver were regarded originally as of Tertiary age and both were found to contain fairly abundant vertebrate remains belonging to turtles, croco- diles, dinosaurs, and, it was at first supposed, mammals. These remains were studied by O. C. Marsh, and at first the study resulted in great confusion. The dinosaurs from the Den- ver were pronounced to be “typical Jurassic dinosaurs of both herbivorous and carhivorous types.” ** Though found in the same beds, what was described as a bison was referred to latest Pliocene time. Later these dinosaurs and the supposed bison were found to belong to the Ceratopsidae, a group of horned dino- saurs especially abundant in Converse County, Wyo., to which consideration will be given in subsequent pages. This determination, accord- ing to the vertebrate paleontologists, fixed their age as Cretaceous. The invertebrates consisted of a few rather poorly preserved fresh-water types that did not prove of much value in fixing the age. Fossil plants were abundant, especially in the Denver beds, but, as already stated, the specimens collected were not labeled with the names of specific localities, and all were re- garded as of Laramie age. Before they could be. utilized in the light of this newer informa- tion as regards their stratigraphic relations, it was necessary to separate them on the basis of the matrix. They were fortunately pre- served in the United States National Museum, and a study of the matrix undertaken by Cross resulted in showing that they were abundantly distinct from those of the underlying Laramie— in fact, out of about 98 species in the Laramie and some 140 in the Arapahoe and Denver, only about 15 nominal species were found in common. Subsequent studies of the Arapahoe 58 Cross, Whitman, The Denver Tertiaby formation: Colorado Sci. Soc. Proc., vol. 3, pp. 119-133, 1888. Recast and republished under the same title in Am. Jour. Sci., 3d ser., vol. 27, pp. 261-282, 1889. 59 Cannon, G. L., On the Tertiary Dinosauria found in Denver beds: Colorado Sci. Soc. Proc., vol. 3, p. 143, 1888. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. and Denver plants have shown them to be essentially Tertiary in type. In 1892 Cross briefly reviewed the rela- tions of the Arapahoe and Denver formations of the Denver Basin and also enumerated additional localities in the Huerfano Basin, Gunnison County, the Yampa River region, the Animas River region, Middle Park, and else- where, in which identical or similar strati- graphic relations had been suggested. He discussed at length the conflicting paleonto- logic evidence of the age of the lake-bed deposits and concluded as follows: The writer wishes to advocate the restriction of the term Laramie, in accordance with its original definition, to the series of conformable beds succeeding the marine Montana Cretaceous, and the grouping of the post-Laramie lake beds described, with their demonstrated equivalents, in another series to which a comprehensive name shall eventually be given. * * * The question as to whether the series shall be referred to the Cretaceous or to the Eocene can not be finally settled until the various conflicting elements of the evidence have been adjusted on a basis of further and more exact information. Later in the same year Cross * published an article on the post-Laramie beds of Middle Park, as an amplification of the previous brief notice. In this article he showed that the large area referred to the “Lignite”’ or Laramie was occupied by a thick series, of mainly andesitic rock resting unconformably on marine Cretaceous beds, with no evidence that the Laramie had ever been present. These beds, which he called the Middle Park beds, were correlated with the Denver on account of the lithologic similarity and the identity of the contained flora. The publication of the Denver Basin mono- graph by Emmons, Cross, and Eldridge” was delayed until 1896, and in many ways the delay was perhaps of advantage, for it per- mitted the incorporation and discussion of many important facts that had in the meantime been made available regarding the strati- graphic and other relations of the determined or supposed correlatives of the formations here under discussion. The Laramie, Arapa- hoe, and Denver formations of the Denver Basin were, of course, described in detail, and the unconformable relations between the Laramie and overlying Arapahoe were espe- Cross, Whitman, Post-Laramie deposits of Colorado: Am. Jour. Sci., 3d ser., vol. 44, pp. 19-42, 1892. 6 Cross, Whitman, Colorado Sci. So2. Proz., vol. 4, pp. 192-213, 189.2 62 U.S. Geol. Survey Mon. 27, 1896. ‘ | Laramie. 17 cially made plain. The magnitude of the time interval represented by the unconformity was insisted upon as of major importance in Rocky Mountain geology. The Arapahoe and Denver formations were ‘in this monograph referred to the Cretaceous ‘out of deference to the views of the vertebrate paleontologists, as it had been found that the vertebrates appeared to be much more nearly allied to Mesozoic than to Cenozoic types. The lithologic and stratigraphic relations of these formations, as well as a very full dis- cussion of the several lines of paleontologic evidence, are given by Cross, who prepared this portion of the volume. In the light of sub- sequent development it has been found that many of his queries and adumbrations have had a wide and increasingly important appli- cation. For ten years after the publication of the Denver Basin monograph little active work was prosecuted in this region, though investi- gations in adjacent or more remote areas were found to have a more or less direct bearing on the problem here involved. In 1907 A. C. Veatch,* from studies in Carbon County, Wyo., was led to question the validity of the current application of the term Laramie. He endeavored to prove that Carbon, Wyo., was intended by King to be the type locality for the In this vicinity Veatch discovered that. in the supposedly continuous Laramie section there is a profound unconformity similar to that found by Cross in the Denver Basin, and as the beds at Carbon studied and described by the members of the King Survey are all above this break he contended that the name should properly be applied only to these beds and not to the beds that are conformable to the Cretaceous section. Veatch further held that the delimitation of the Arapahoe and Denver constituted a virtual redefinition of the Laramie. Replies to this paper were made by Cross * and Peale,“ and it is sufficient to state that the view advocated by Veatch has not been adopted. Cross especially reviewed the facts relating to the application of the term, hold- 8 On the origin and definition of the geologic term Laramie: Am. Jour. Sci., 4th ser., vol. 24, p. 18, 1907; expanded under the same title im Jour. Geology, vol. 15, p. 526, 1907. % Cross, Whitman, The Laramie formation as the Shoshone group: Washington Acad. Sci. Proc., vol. 11, pp. 27-45, 1909. % Peale, A.C., On the application of the term Laramie: Am. Jour. Sci., 4th ser., vol. 28, pp. 45-58, 1909. 18 LARAMIE FLORA OF ing that the separation of the Arapahoe and Denver did not constitute redefinition, and finally, following a suggestion made by himself in 1892, proposed for the latter and their equivalents the term Shoshone group. He said: It is proposed to apply the term Shoshone group to the déposits which unconformably succeed the Laramie and to their equivalents and which are overlain by the Fort Union or Wasatch beds when they are present. In this paper Cross reviewed briefly the data bearing on the age of these post-Laramie beds and concluded as follows: In the preceding discussion I have avoided the question as to the age of Shoshone beds, whether Cretaceous or Eocene. I desire now to urge their reference to the Eocene. The Denver beds were originally referred by me to the Eocene, but the great weight attached to the Mesozoic affinities of the vertebrate fauna by paleontolo- gists led to a tentative acquiescence in the assignment of the Arapahoe and Denver formations to the Cretaceous in the Denver monograph. RATON MESA REGION OF COLORADO AND NEW MEXICO. In 1907 a series of observations were begun in the Raton Mesa region of southern Colorado and northern New Mexico, which were found ultimately to have an important bearing on the formations under discussion in the Denver Basin. The Canon City field of Colorado, although slightly extralimital, is here included in. the Raton Mesa region, which really begins with Walsenburg, Colo., and vicinity and extends southward to Cimarron River, N. Mex. The early history of geologic exploration and inter- pretation in this region has already been given in the historical review of the time which pre- ceded the establishment of the term Laramie, and in this connection it is only necessary to mention the names of, Le Conte, Lesquereux, Hayden, Newberry, and Stevenson as among those who took principal parts in the discus- sion. The section of coal-bearing rocks in this region was considered by one set of students as being more or less directly the equivalent of the “Lignite group” of the north and Tertiary in age. The opposing students regarded the age as Cretaceous, but when the Laramie was established by King the definition appeared to fit the Raton Mesa section, and consequently the beds in this area soon came to be accepted as of Laramie (Cretaceous) age. It should not THE DENVER BASIN. be overlooked, however, that from his studies of the fossil plants Lesquereux was led to insist that the flora of certain localities within this area, notably Raton Pass and Fishers Peak, indicated a correlation with the so-called ‘‘EKo- lignitic” (=Wilcox formation) of the Gulf region and was of Tertiary age. A critically annotated historical review of geologic and paleontologic literature on this region is given in a recent paper by Lee and Knowlton, to which the reader is referred for full particulars. In the present connec- tion it is sufficient to begin with the time— about 1900---when geologists had reached a general agreement that the coal-bearing rocks of the Raton Mesa region are of Laramie age and, moreover, that sedimentation had been continuvus and uninterrupted throughout the deposition of this section. Thus,. in my “Catalogue of the Cretaceous and Tertiary plants of North America,” published in 1898, the plants from the Raton region were referred to the Laramie as then currently accepted. In Newberry’s long delayed mono- graph on the later extinct floras of North America, also issued in 1898, the few species from this region were referred without ques- tion to the Laramie. In the Walsenburg and Spanish Peaks geologic folios, hy R. C. Hills,” issued in 1900 and 1901, respectively, the pro- ductive coal measures were referred to the Laramie without qualification. In 1909, however, W. T. Lee” published a short paper under the title “ Unconformity in the so-called Tiaramie of the Raton coal field, New Mexico,” in which the following was given as the thesis: The purpose of this paper is to describe an uncon- formity hitherto unknown that is of more than ordinary interest because it divides rocks previously referred to the Laramie into two distinct formations. * * * Dur- ing the time interval represented by the unconformity the sedimentary rocks previously laid down within the Raton field were subjected to erosion for a considerable length of time, and the Rocky Mountains west of this field were elevated and eroded to a depth of several thousand feet. Lee further pointed out that 6 Lee, W. T., and Knowlton, F. H., Geology and paleontology of the Raton Mesa and other regions in Colorado and New Mexico: U. S. Geol. Survey Prof. Paper 101, pp. 17-37, 1918. 8 Knowlton, F. H., U. S. Geol. Survey Bull. 152, 1898. 6 Newberry, J. S., U. S. Geol. Survey Mon. 35, 1898. ® Hills, R. C., U. S. Geol. Survey Geol. Atlas, Walsenburg folio (No. 68), 1900; Spanish Peaks folio (No. 71), 1901. 70 Lee, W. T., Geol. Soc. America Bul]., vol. 20, pp. 357-358, 1909. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 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 position of the Lara- mie of the Denver Basin but contains a flora that is ap- parently older than Laramie. As regards the significance of this uncon- formity Lee added: There are several possibilities of interpretation, as will be pointed out in the following pages, but the one con- sidered most probable is that the uplift and erosion rep- resented by the unconformity were contemporaneous with the post-Laramie uplift and erosion described by Cross and others from the Denver region. Without unduly anticipating, it may be stated that subsequent work has entirely confirmed this interpretation. In 1910 G. B. Richardson,” in a short report on the coal resources of the Trinidad coal field of Colorado, noted the conglomerate described by Lee in the report on the Raton coal field as marking the unconformity and said: The significance of the conglomerate in the Trinidad field remains to be determined. - Occurring intermittently in the midst of coal-bearing rocks, it may represent only a local change in conditions of deposition, or, as maintained by Lee for a conglomerate in the Raton field, presumably the same as the one just described, it may mark an uncon- formity contemporaneous with the post-Laramie uncon- formity of the Denver Basin. * * * The final word concerning the age of the rocks above and below this con- glomerate in the coal measures, involving its significance as a hiatus marker, must come from the paleontologist. As the paleobotanic data then tentatively supplied by me were more or less conflicting and inconclusive, Richardson wisely enough concluded that Until further paleobotanical knowledge is available, the age of these rocks must remain unsettled. For the present it seems best to retain the old nomenclature and to refer the strata occurring between the Trinidad sandstone and the Poison Canyon formation to the Laramie. In the same volume with Richardson’s report is a paper by C. W. Washburne ” on the Canon City coal field, Colo., in which he stated that The Laramie formation, which contains all the coal beds of the Canon City field, rests conformably on the Trinidad sandstone and is unconformably overlain by the Arapahoe (?) conglomerate. The productive division of the forma- tion is the lower 600 or 700 feet. ‘Although Washburne admitted that the “upper part of the coal measures contains a 1” Richardson, G. B., The Trinidad coal field, Colo.: U. S. Geol. Survey Bull. 381, pp. 379-446, 1910. 2 U.S. Geol. Survey Bull. 381. pp. 341-378, 1910. 19 flora equivalent to that of the Laramie for- mation of the Denver Basin, while the lower part contains a flora of upper Montana age,”’ he concluded that “there seems no good reason for separating these lower beds from the Lara- mie, even though they contain an upper Montana flora.” The work on the stratigraphy and paleo- botany of this region was continued by Lee and Knowlton,” and their results were presented for publication early in 1913. These results I briefly summed up in May of that year as follows: ™ | In 1907 W. T. Lee began the study of the coal in the Raton field, and while prosecuting this work he discovered the presence of an unconformity in the midst of the section of coal-bearing, supposed Laramie rocks. This uncon- formity was traced throughout the entire Raton Mesa and subsequently was carried around the southern end of the mountains and well up along their western front. The rocks below the unconformity, to which the name Vermejo formation has been given, have a maximum thickness of only about 375 feet, while the rocks above the uncon- formity, now called the Raton formation, are about 1,600 feet in thickness. In some places the Raton formation rests on the full thickness of the Vermejo formation, while in other localities the Vermejo is greatly reduced, and in at least one place the entire Vermejo, together with the underlying Trinidad sandstone, has been removed and the Raton rests directly on Pierre. When the unconformity had been demonstrated, .it became of the greatest interest and importance that the fossil plants should be studied to ascertain their bearing, first, on the distinctness of these two formations, and, second, on the question of age. * * * The total flora of the Raton Mesa region comprises 257 forms, of which number 106 belong to the lower, or Vermejo and Trinidad formations, and 151 to the upper, or Raton formations. Only 4 species have been found to cross the line of the unconformity, which is taken as pretty conclusive evi- dence of the distinctness of the two formations. * * * The Vermejo formation is shown by the plants to be Creta- ceous (Montana) in age, being in the approximate position of the Mesaverde. The Raton formation is shown to be essentially of the same geologic age as the Denver formation of the Denver Basin and of the Wilcox formation of the Gulf region, the latter being indisputably of Eocene age. The conclusion is therefore reached that the Raton and Denver formations are Eocene in age. In the meantime, as indicated above, Lee had continued the studies from Raton Mesa around the south end of the Rocky Mountains and well 7 Lee, W. T., and Knowlton, F. H., Geology and paleontology of the Raton Mesa and other regions in Colorado and New Mexico: U. S. Geol. Survey Prof. Paper 101, 1918. 74 Knowlton, F. H., Results of a paleobotanical study of the coal- bearing rocks of the Raton Mesa region of Colorado and New Mexico; Am. Jour. Sci., 4th ser., vol. 35, pp. 526-530, 1913, 20 up along the west side. His results were set forth in a paper published in 1912.” COLORADO SPRINGS AREA. Although the Colorado Springs area is in practical connection with the Denver Basin and in fact is considered a part of the basin in the present study, there are reasons that make it desirable to treat this area ‘separately and specifically. The first fairly comprehensive account of the geology of this area was given in 1869, by F. V. Hayden,” who made a reconnaissance study from Cheyenne, Wyo., through the Denver Basin, Colorado Springs, Canon City, and Raton fields. At that time he considered the coal-bearing rocks as belonging to the “ Lig- nitic” and of Tertiary age. In 1872 Leo Lesquereux ” visited this region and gave a brief account of the geologic rela- tions of the coal-bearing rocks, including a sec- tion of the rocks at the Gehrung coal mine, north of Colorado Springs, which he considered as similar to the section in the Raton Moun- tains. A list of the fossil plants collected is given on page 375 of his report. In the following year A. C. Peale ® also gave a short account of the geology of the Colorado Springs area, but it was mainly a confirmation of the work of Lesquereux, whose section at the Gehrung mine he quoted. Peale also visited the Franceville coal mines, about 12 miles east of Colorado Springs, and identified portions of the section with that at the Gehrung mine. The fossil plants he obtained at this locality are enumerated on pages 326-375 of his report. At this point it is necessary to speak of the so-called Monument Creek group, on account of the part it played in the elucidation of the geologic history of this region. The term “Monument Creek group” was established by Hayden” for a series of ‘‘variegated beds of sands and arenaceous clays, nearly horizontal, 7 Lee, W. T., Stratigraphy of the coal fields of northern central New Mexico: Geol. Soc. America Bull., vol. 23, pp. 571-686, 1912.. As already indicated, the cymplete report on the Raton Mesa region by Lee and Knowlton was published in 1918 as U.S. Geol. Survey Prof. Paper 101; ’ to this report the reader is referred for details of the geology and paleo- botany. 76 Preliminary field report of the United States geological survey of Colorado and New Mexico, pp. 37-46, 1869; reprint, pp. 137-146, 1873. 1% The Lignitic formation and its fossil flora: U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, pp. 325-327, 1873. 78 Peale, A. C., U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1873, pp. 202-203, 1874. 79 Op. cit., p. 40. LARAMIE FLORA OF THE DENVER BASIN. resting on the upturned edges. of the older rocks, * * * of various colors * * * and of various degrees of texture.’’ This series occurs along the Front Range on the divide be- tween the Platte and Arkansas drainage, where it covers an area “of about 40 miles in width from east to west, and 50 miles in length north and south.” From its modern appearance Hayden concluded that it was of “either late Miocene or Pliocene age.” In 1873 Cope ® referred to the “Monument Creek”’ as follows: e ‘ The age of the Monument Creek formation in relation to the other Tertiaries not having been definitely deter- mined, I sought for vertebrate fossils. ‘The most charac- teristic one I procured was the hind leg and foot of an artiodactyl of the Oreodon type, which indicated conclu- sively that the formation is newer than the Eocene. From the same neighborhood and stratum, as J have every reason for believing, the fragment of the Megaceratops [obvious error for Megacerops] coloradoensis was obtained. This fos- sil is equally conclusive against the Pliocene age of the formation, so that it may be referred to the Miocene until further discoveries enable us to be more exact. In the following year (1874) Hayden * again referred to the ‘‘Monument Creek group.” After describing it at some length, and alluding to Cope’s statement regarding the vertebrate evidence, he said: ‘‘As to the real age of this group, I am inclined to regard it as Miocene, perhaps upper Miocene.” The next: publication that it is necessary to notice is the Denver Basin monograph, 2 by Emmons, Cross, and Eldridge, though in that work the discussion of these rocks was brief, as they occur in the series of beds mapped only as projecting tongues forming the divide be- tween the Platte and Arkansas waters. Em- mons gave first a brief summary (p. 38) in which, although calling the beds the ‘‘Monu- ment Creek formation,” he, noted that ‘‘two divisions have been distinguished, marked by an apparent unconformity and period of erosion.” The lower division was referred tentatively to the Miocene on the basis of the previous vertebrate work of Cope, while the upper division was thought probably to be referable to the Pliocene. Eldridge devoted several pages to a general description of the stratigraphic relations, Jith- % Cope, E. D., Report on the vertebrate paleontology of ( olorado: U.S. Geol. and Geog. Survey Terr. Ann Rept. for 1873, p. 430, 1874. 81 Hayden, F, V., U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, pp. 36, 37, 1876. 8 Emmons, 8. F., Cross, Whitman, and Eldridge, G. H., U. S. Geol. Survey Mon. 27, pp. 38, 39, 252-254, 1896. HISTORICAL REVIEW OF ology, and life of the ‘‘Monument Creek forma- tion,’ which was of course the basis for the general statement by Emmons. | Concerning the stratigraphic relations Eldridge said: The Monument Creek formation occurs along the southern edge of the Denver field in the steep slopes of a high mesa and also stretches from its base prairieward : in thin sheets. The floor of the lake in which the Monu- ment Creek was deposited was more or less irregular from erosion and in one part or another consisted of the clays and sandstones of the Laramie, Arapahoe, or Denver’ formations. In the foothill region the Monument Creek | lies in contact with the Arapahoe; between Platte River and Cherry Creek a few hundred feet of Denver beds exist, which further to the east disappear. North and‘ east of Coal Creek, on ‘the eastern edge of the field, both. Denver and Arapahoe are wanting and the Monument: Creek rests directly upon the clays of the Laramie. Although the relations between the Arapahoe and Denver and the ‘‘Monument Creek’’ were somewhat obscure, the interpretation natur- ally followed that the latter was structurally’ above the former, for it was then supposed that the lower division of the ‘‘Monument Creek” was of Miocene age, while the Arapahoe’ and Denver were referred to the Cretaceous. | In 1902 W. T. Lee ® discussed at some length: the “Monument Creek group” of Hayden. To the lower portion (of Emmons and others) he applied the name ‘Monument Creek forma- tion’’ and described it as ‘composed of con- glomerates, breccias, sands, and clays which alternate-and intermingle and grade into each other in the most lawless manner.” Continu- ing, Lee said: Above the Monument Creek beds lie masses of rhyolitic tuff. This tuff has been noted by Hayden and others. It forms more or less of a sheet, or sheets in some places, while in others it occurs intermingled with sand, gravel, and clay. * * * Above the tuff occurs a sheet of glassy rhyolite about 25 feet thick which forms the protecting cap of several of the buttes near Castle Rock. To the “youngest formation in the Castle Rock region” Lee gave the name ‘Castle con- glomerate.” This was the “Upper Monument Creek” of Hayden and the so-called upper divi- sion of Emmons and others. Concerning it Lee said: These upper beds differ in character from those of the lower division; they are separated from it by volcanic tuffs and flows of rhyolite and by an unconformity representing a period of erosion, as shown by the presence in it of the material from the underlying rhyolite. It is therefore separate and distinct from the lower division. 83 The areal geology of the Castle Rock region, Colo.: Am. Geologist, vol. 29, pp. 101-103, 1902. THE LARAMIE PROBLEM. 21 Lee did not procure data bearing on the age of the divisions of the ‘Monument Creek’’ recognized by him, but three years later N. H. Darton * obtained additional vertebrate evi- dence as regards the upper division. At a number of localities he collected remains of Titanotherium and Hyracodon, concerning which he wrote as follows: All this material appears to have been obtained from the upper beds and it correlates these beds with the Chadron formation of the White River group, or Oligocene. No evidence was obtained as to the age of the lower member. * * * The presence of the unconformity between the upper and lower members suggests that the latter may be of Wasatch or Bridger age. The nearest locality to the Monument Creek area at which Oligocene deposits occur in eastern Colorado is in the vicinity of Akron and Fre- mont’s Butte, where Titanotherium remains occur in abundance. The.status of the “Monument Creek” prob- lem remained as above indicated until 1910-11, when :G. B. Richardson began a study of this region preparatory to the preparation of a report on the geology of the Castle Rock quad- rangle, which is joined by the Denver Basin on the north and by the Colorado Springs quad- rangle on the south. As a result of this study Richardson * stated that he found it necessary to separate the ‘“‘Monument Creek group’’ into two formations on the basis of a well-marked unconformity which separates beds of Eocene and Oligocene age. The lower formation was named the Dawson arkose and the upper one the Castle Rock conglomerate. According to Richardson the stratigraphic relations indicate that the Arapahoe and Denver formations are equivalent to the lower part of the Dawson arkose, and this evidence is paleontologically supported. The Castle Rock conglomerate may be first considered. This’ formation is the ‘Upper Monument Creek” of Hayden and others, the so-called ‘‘upper division of the Monument Creek” of Emmons, Eldridge, Darton, and others, and the Castle conglomerate of Lee.** It occurs in the south-central part of the Den- ver Basin, where it crops out in detached areas on the divides between the tributaries of South Platte River from a point near Elbert to the vicinity of Sedalia, a distance of about 40 miles. &4 Age of the Monument Creek formation: Am. Jour. Sci., 4th ser., vol. 20, pp. 178-180, 1905. . 85 Richardson, G. B., The Monument Creek group: Geol. So?. America Bull., vol. 23, pp. 267-276, 1912. 86 Lee's name was unavailable on account of prior usage. 22 LARAMIE FLORA OF It is thus a remnant of a once larger formation that has been reduced by erosion. Concerning its stratigraphic relations Richardson said: Everywhere the Castle Rock conglomerate rests on an undulating surface of the underlying Dawson arkose, and there is an abrupt change in texture of the material from the medium or fine grained arkose of the upper part of the Dawson to the coarse Castle Rock conglomerate. Richardson procured additional vertebrate remains from the Castle Rock conglomerate, which were identified by J. W. Gidley, of the United States National Museum, as Titanothe- rium, and the correlation of these beds with the Chadron formation, the lower formation of the Oligocene White River group, was thus con- firmed. More interest attaches to the Dawson ar- kose—that is, the lower division of the ‘‘Mon- ument Creek group”-—for its exact age had long been in doubt. It has a maximum thick- ness of about 2,000 feet on the west, toward its source in the mountains, and is thinner toward the east. Its appearance was de- scribed by Richardson as follows: The formation is a complex aggregate of varicolored and varitextured conglomerate, sandstone, shale, and clay, de- rived from the rocks of the Front Range and deposited under a variety of continental conditions. They are me- dium to coarse textured arkosic grits, composed chiefly of quartz and feldspar derived from the Pikes Peak granite and associated rocks. * * * MRhyolitic rocks * * * were extravasated on an uneven surface of arkose in the extreme upper part of the Dawson. * * * The strati- graphic relations of the Dawson arkose to the Denver and Arapahoe formations * * * are generally concealed by a cover of Quaternary deposits, so that actual conditions are obscure. It is not claimed for the recent work that. final correlations have been established, but nevertheles previously unsuspected relationships are indicated. Approaching the geologically mapped part of the Denver Basin from the south, where detailed work had not previously been done, it was found that the lower part of the Dawson arkose seems to pass along the strike into the Arapahoe and Denver formations; that the Dawson and Arapahoe can not be separated lithologically, even at the type locality of the Arapahoe, on the bluffs of Willow Creek; and that the Denver and Dawson apparently merge into each other, or interdigitate, layers of arkose typical of the Dawson being found intercalated in andesitic Denver material. These conditions indicate that the Arapahoe and Denver are equivalent to the lower part of the Dawson arkose. The marked difference in lithology between the andesitic Denver and the arkosic Dawson may be accounted for by the geographic distribution of the rocks which supplied the sediments. The paleontologic support of the age deter- mination of the Dawson arkose consists of a number of collections of fossil plants, which THE DENVER BASIN. are pronounced to be of undoubted Denver age, and a single bone of a mammal, which was identified by Gidley as that of a creodont and of which he said: ‘‘From our present knowledge of the creodonts such a type could not be older than Wasatch.”’ Although no dinosaurs were found by Richardson in the Dawson arkose, he referred to their occurrence, as reported by Marsh, in Monument Park, 8 miles north of Colorado Springs, in beds that must belong to the Dawson. Ceratopsian dinosaurs have been found in the Arapahoe and Denver formations, but not thus far in the Laramie of the Denver Basin. In 1912, however, Lee * visited the locality where the creodont bone above mentioned was found (Jimmy Camp Creek, 9 miles east of Colorado Springs) and there collected the remains of turtles and of dinosaurs. The tur- tles were examined by O. P. Hay and the dino- saurs by C. W. Gilmore. Mr. Gilmore reported on these bones as follows: The collection consists of fragmentary ceratopsian bones none of which is sufficiently characteristic to determine the genus to which it belongs, and one ungual phalanx is doubtfully regarded as belonging to the dinosaur Tracho- don. Two small shell fragments show the presence of hard and soft shell turtles. Of these Dr. Hay says: ‘“‘The soft shell resembles those of the Lance formation; the other resembles those of the Wasatch but is too fragmentary to be certain of its affinities.”’ In commenting on the above statements Lee wrote: We have then at this locality, near Colorado Springs, in beds that lie unconformably on the Laramie, a flora that correlates these beds with undoubted Eocene on the one hand, and on the other with the Denver and Arapahoe formations; a mammal of a type not known here- tofore to be older than Wasatch; a turtle whose nearest known allies are in the Wasatch fauna; another that resembles those of the Lance fauna; and dinosaurs that have been somewhat generally regarded as indicative of Cretaceous age but which occur in associations that convince some geologists that they are Tertiary. Con- sidering this association of fossils in connection with the great unconformity, it seems wholly irrational longer to regard a formation as Cretaceous merely because it contains dinosaurs. We may now return to the more direct con- sideration of the Laramie of the Colorado Springs region. In 1908 M. I. Goldman * spent some months in the investigation of the 81 Lee, W. T., Recent discovery of dinosaurs in the Tertiary: Am. Jour. Sci., 4th ser., vol. 35, pp. 531-534, 1913. *8 The Colorado Springs coal field, Colo.: U. 8. Geol. Survey Bull 381, Pp. 317-340, 1910. HISTORICAL REVIEW OF THE LARAMIE PROBLEM, coal resources of this area, and after describing briefly the Pierre shale and Fox Hills sandstone, he wrote as follows concerning the Laramie: Above the Fox Hills sandstone lie the coal-bearing rocks of Laramie age. These may be divided into two mem- bers—a lower including several massive sandstone beds and three or more of the most important coal beds of the field, and an upper composed of clay shale, sandy shale, and some sandstone with poorly developed coal beds. The best exposure of the sandy, coal-bearing member is in Popes Bluff, where the base of the formation is com- posed of a massive sandstone from 40 to 100 feet thick but not sharply defined from the underlying Fox Hill. The upper part of the sandstone member of the Laramie gives way gradually, toward the east, to shale with thin beds of calcareous and ferruginous sandstone about 250 feet thick. In the western part of the field the sandy member is about 200 feet thick. Owing to the incompleteness of the paleon- tologic evidence, mainly that of fossil plants, Goldman did not make definite age determina- tions for the rocks above the Laramie, which were described under the terms ‘“conglom- erate,” “andesitic material,” and ‘“arkose,” in ascending order. In some parts of the field the shaly part o1 the Laramie is overlain by a conglomerate, which has a maximum known thickness of about 30 feet. ‘The lithologic similarity of this bed to some parts of the Arapahoe forma- tion in the Denver Basin is apparent.” At a number of localities the conglomerate is overlain by beds of andesitic material, ‘“ which in lithologic composition is similar to the Den- ver formation.” The average thickness of the beds of andesitic material is about 125 feet. Beds of arkose lie unconformably upon the andesitic material and overlap the coal-bearing sandstone in the southeast corner of sec. 6, T. 13 S., R. 67 W. The arkose has two phases—(1) coarse arkose near the mountains, some sandstone, and clay containing coarse quartz grains; (2) fine-grained, very micaceous sandstone. Both phases are very irregularly bedded, and most of the lithologic units are of small horizontal extent. The greatest thickness of arkose measured was 300 to 400 feet-in Corral Bluffs, but the total thickness was believed to be still greater. A number of collections of fossil plants made in the immediate Colorado Springs area by A. C. Peale, M. I. Goldman, and others were submitted to me for study at this time (1908). This material was not well preserved, owing to the friable nature of much of the matrix, and it was studied with difficulty. With the ma- terial available I was not then able to differen- 23 tiate the three formational units—Laramie, Arapahoe, and Denver—that were theoretically inferred to be present; in fact, the Laramie elements appeared to preponderate so greatly that I was inclined to refer all the plant collec- tions to the Laramie. On bringing together in a single list all the forms enumerated in these collections, as well as those reported originally by Lesquereux from the Gehrung mine and Franceville—both in the acknowl- edged Laramie—it was found that a total of 49 forms were represented. Of these 22 were not specifically determined, leaving 27 named species, most of which were known outside the Colorado Springs area. On analysis, it ap- peared that 19 of these forms were found in Laramie or older beds, but, as will be pointed out later, nearly all of these are found in the lots which belong to the Laramie and about which there is no question. There was one lot, however, collected high in the section of the bluffs just west of Templeton Gap that as then identified did much to influence my refer- ence of these beds to the Laramie. As origi- nally listed this lot contained the following forms: Sequoia brevifolia Heer. Sequoia longifolia Lesquereux. Dammara sp. cf. D. acicularis. Salix? sp., fragment. Ficus trinervis Knowlton, fragment. Rhamunus salicifolius Lesquereux. Cyperacites sp. Viburnum? sp. Carpites sp. (poor). At the time these identifications were made the “Monument Creek group” was supposed to be of Oligocene age, and it was deemed absolutely impossible that these plant remains could be of this age; in fact, if they were correctly identified and stood alone, there would ordinarily be no hesitation in referring them to the Laramie, which I did. Since that time, however, I have twice visited this region and collected material from this locality, as well as from neighboring localities of similar stratigraphic position, and I have also collected material and studied several collections made some 20 miles or more to the east, out on the plains, with the result that I have acquired a better understanding of the forms represented and their stratigraphic relations. A number of the species of plants from the Pulpit Rock area are the same as those occur- 24 LARAMIE FLORA OF ring at Black Buttes, Wyo., in beds which were then supposed to be in the Laramie but which in my opinion subsequent work has shown pretty conclusively to be of post-Laramie age. This naturally makes a difference in the weight given to Laramie position. Furthermore, as already stated, much of the material from Pulpit Rock and vicinity is very fragmentary and difficult to identify satisfactorily, but in the light of the material obtained farther east it becomes clearer, and this has permitted certain revisions of earlier determinations. Below are the lists from Templeton Gap and vicinity; the first one is a revision of the one given above: Bluffs west of Templeton Gap: Sequoia obovata? Knowlton ined. Sequoia acuminata Lesquereux. Dammara sp. ' Cyperacites sp. Salix sp. Ficus trinervis Knowlton. Rhamnus-salicifolius Lesquereux. Carpites sp. (Palmocarpon?). . Palmer’s ranch, Templeton Gap, 4 miles northeast of Colorado Springs: Carpites sp. Sequoia sp.? Palmer’s ranch, half a mile farther west: Rhamous salicifolius? Lesquereux. Platanus? sp. Viburnum sp., probably new. These lots may be considered together. the four named species, two (Sequota acumi- nata and Ficus trinervis) were described | originally from specimens obtained at Black Buttes, Wyo.; the other two are survivals from. Of these the Rhamnus : the Laramie or older. is well known as crossing the line between Cretaceous and Tertiary, but the Sequoia had not previously been recognized as doing this. The Sequoia, however, is represented only by a single rather poorly preserved branchlet and may not be correctly determined. The Dam- mara is apparently an undescribed form; it is Cretaceous in type, though the genus is still living. The several localities above mentioned as lying out on the plains to the east and north- east of Colorado Springs may now be con- sidered. It is a well-known fact that the Laramie, as well as certain overlying beds. stands at acute angles in many places near the mountains, but within a few miles the dips rapidly diminish and the beds become nearly Of THE DENVER BASIN. horizontal. Thecountry becomes grass covered, rock exposures are few and far between, and sections showing the contacts of the forma- tional units are still fewer. It is especially difficult to establish satisfactorily the line between the Laramie and the overlying beds in this plains region, and recourse must be had to paleontology in the allocation of the more or less isolated localities. A number of plant collections have been made at these uncertain points in the section. According to Richardson, by whom most of these collections were made, the plant-bearing beds are 1,000 feet or more, as determined by drill renonde: above the Fox Hills, and be- tween 20 and 150 feet below a bed of conglom- erate that marks the base of a thick deposit of coarse-grained light-colored arkose which is lithologically quite distinct from the underlying fine-grained drab and buff-colored plant-bearing sandstones and shales resem- bling the typical Laramie. It is suggested by Richardson, on stratigraphic grounds, as a possibility worth considering that these leaves come from a horizon high in the Laramie, approximately equivalent to the Scranton coal zone 15 miles east of Denver, from which few leaves have heretofore been collected. Below are the lists of plants from the locali- ties mentioned: Near Mosby, Colo., 30 feet above coal: Flabellaria? sp., fragmentary. Pteris undulata Lesquereux. Anemia. Equisetum sp. Ficus denveriana? Cockerell. Laurus socialis Lesquereux. Laurus wardiana? Knowlton. Viburnum marginatum? Lesquereux. Sapindus sp. One-fourth mile east of Purdon’s mine, Colo.: Platanus haydenii Newberry. Nelumbo? new, fine. Hedera sp., new, fine. Populus nebrascensis Newberry. Ficus sp.? Sapindus sp.? Red Hill, 4 miles south of Ramah, Colo.: Platanus raynoldsii Newberry. Vitis olriki Heer. Cissus lobato-crenata Lesquereux. Myrica? sp.? NW. 3 sec. 30, T. 9 S., R. 60 W., 50 feet below conglomerate: Platanus sp. cf. P. haydenii? Platanus rhomboidea Lesquereux. Populus sp.? HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 24 miles southwest of Norton, Colo.: Platanus sp. Ficus denveriana Cockerell. Populus sp. Hicoria antiquora? (Newberry) Hollick. Palm rays, gen.? Salix angusta? Alex. Braun. Ficus denveriana Cockerell. Populus sp.? Magnolia? Laurus? sp., fragments, Fraxinus eocenica Lesquereux. Half a mile southeast of Ramah oil prospect, Colo.: Lygodium kaulfusii Heer. Anemia lanceolata Knowlton. Myrica like M. torreyi, but without teeth. Ficus sp. cf. F. denveriana Cockerell. Laurus sp. Populus sp. cf. P. nebrascensis Newberry. On bringing the named forms together we have the following list: Pteris undulata. Platanus raynoldsii. Lygodium kaulfusii. Platanus rhomboidea. Anemia. Vitis olriki. Hicoria antiquora? Cissus lobato-crenata. Salix angusta? Laurus socialis. Laurus wardiana? Magnolia? Fraxinus eocenica? Viburnum marginatum. Populus nebrascensis. Ficus planicostata. Ficus denveriana. Platanus haydenii. As this list stands, and on the assumption that the determinations have been correctly made, no one familiar with the several floras of the Denver Basin would hesitate, I think, to pronounce this a distinctly post-Laramie flora. If we eliminate the six species of which the identification is questioned and confine attention to positively determined forms, it follows that only two species from this list— Ficus planicostata and F. denveriana—have been admitted into the Laramie flora as set forth in the present work. As may be seen by consulting the description (p. 131), Ficus planicostata is a wide-ranging form that oc- curs in the Montana, Laramie, Wilcox, and Denver formations and the beds at Black Buttes, Wyo., while F. denveriana (see p. 138) is essentially a Denver species, and the evi- dence of its presence in the Laramie consists of a single more or less imperfect leaf from Popes Bluff, near Colorado Springs, the iden- tification of which is properly questioned. A further analysis might be made of the forms not specifically named in the above lists; but this is not deemed necessary, as it can be confidently asserted that their affini- 25 ties undoubtedly lie with post-Laramie rather than with Laramie species. It will thus be seen that, as now under- stood, the plants do not lend support to the suggestion that these beds are of Laramie age, and they have not been included in the present work. If it should ultimately be shown that these horizons are really in the upper part of the Laramie and not in post- Laramie beds, such a result would help to break down the marked distinction now be- lieved to exist: between the flora of the Lara- mie and that of overlying beds, but this is a contingency which the writer is not now pre- pared to recognize. LANCE FORMATION. The age and proper allocation of what is now very generally known as the Lance formation has been one of the most active of the storm centers about which the Laramie controversy has been waged. As viewed in retrospect, it appears that much of the dis- cordance that arose was due to the varying weight attached to the several available kinds of paleontologic criteria, as will be made plain in the following exposition. The most marked or conspicuous paleonto- logic characteristic of the Lance formation is undoubtedly the presence of the huge dino- saurian reptiles that have been found in it at so many localities, and it is beyond question that this characteristic did much to direct and stimulate investigation of the formation, which might otherwise have been long delayed. The first collection of remains of the group of horned dinosaurs known as the Ceratopsia was made by F. V. Hayden in the vicinity of Judith River, Mont., about 1855, but the dis- ‘ tinctive characters of the group were not dis- covered until more than 30 years later. The material collected by Hayden, consisting of isolated teeth, was described by Joseph Leidy, who tentatively regarded it as of Jurassic (Wealden) age. A fuller discussion of the Judith River problem will be found on page 77. The next in order of discovery was the cele- brated Agathaumas sylvestris Cope, found in 89 Since the foregoing pages were written it has been demonstrated by Lee that the Scranton coal and the beds at a number of localities on Sand Creek and Coal Creek, east of Denver, are of post-Laramie age. This determination has an important bearing on the age of the beds east of Colorado Springs mentioned in this chapter. The discovery made by Lee is explained on page 103. 26 1872 at Black Buttes, Wyo., by F. B. Meek, and later in the same year collected by Cope himself. (See p. 8.) In the following year Cope ® found the-remains of what is now known to be a member of this group at some uniden- tified locality in Colorado, and in 1876 he un- dertook the exploration of the Judith River region, describing a number of remains that from their fragmentary nature he was not able to allocate until the group had been made better known from the studies of O. C. Marsh. « As already mentioned (p. 16), the remains of horned dinosaurs, although not at first so recognized, were found by Lakes, Cross, El- dridge, Cannon, and others in the post-Lara- mie beds of the Denver Basin of Colorado during the period extending from 1881 to about 1887. These were described in part by Marsh. In the summer of 1888 J. B. Hatcher, then assistant to Marsh, found the poorly preserved remains of. a dinosaurian in Wyoming just north of the Seminoe Mountains, on the west side of North Platte River about 40 miles below Fort Steele. The above brief account completes the list _ of discoveries of remains of the Ceratopsia that fall within the present discussion prior to the finding of the celebrated deposits in Converse County, Wyo. These deposits were made known late in the fall of 1888, when a single horn core was brought to the attention of Mr. Hatcher by a resident of the region. This dis- covery was considered so important by Marsh that Hatcher was directed to return to the region at the earliest moment, which was in January, 1889, and from this time until 1895 Hatcher was almost continuously employed in exploring and collecting from these rich de- posits. The material he obtained, which was very extensive and varied, furnished the basis for a series of important papers by Marsh. Before proceeding to the discussion of the Converse County area and its bearing on the question under consideration, it may be well to point out that the family Ceratopsidae, which has become so important in this connec- tion, was established by Marsh * in December, 1888. The exact locality that yielded the specimen on which this family was based was 90 Cope, E. D., Report on the vertebrate paleontology of Colorado: U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1873, p. 429, 1874. 91 Marsh, O. C., A new family of horned Dinosauria, from the Creta- ceous: Am. Jour. Sci., 3d ser., vol. 36, p. 478, 1888. _them may be called the Ceratops beds. LARAMIE FLORA OF THE DENVER BASIN. not recorded by Marsh, who said it “was found in place, in Laramie deposits.of the Cretaceous, in Montana,” and added in the next paragraph: “ Remains of the same reptile, or one nearly allied, had previously been found in Colorado, in deposits of about the same age.’’ Accord- ing to Hatcher the beds of the Montana locality were near the top of the Judith River formation on Cow Creek, 10 miles above its confluence with the Missouri. The Colorado specimen referred to came from the Arapahoe formation of the Denver Basin.* _ Marsh’s first paper * dealing with what is now known to be the Converse County material was published in April, 1889, and describes some Jurassic forms and a single specimen from this region. This was named Ceratops horridus, and in August of the same year it was made the type of the genus Triceratops.® Incidentally it may be, mentioned that this genus was based in part on the horn core first known from these beds as noted by Hatcher. In neither of these papers is there mention of the locality beyond the statement that the remains came from “the Laramie formation of Wyoming.” In December, 1889, a third paper by Marsh * was published, in which, in addition to describ-- ing the skull more in detail, he gave the follow- ing brief statement on the geologic occurrence of the Ceratopsidae: The geological horizon of these strange reptiles is a distinct one in the upper Cretaceous and has now been traced nearly 800 miles along the eastern flank of the Rocky Mountains. It is marked almost everywhere by remains of these reptiles, and hence the strata containing They are fresh- water or brackish deposits, which form a part of the so- called Laramie but are below the uppermost beds referred to that group. In some places, at least, they rest upon marine beds which contain invertebrate fossils character- istic of the Fox Hills deposits. In commenting on this statement a few years later, Cross *” said: %® Hatcher, J. B., The Ceratopsia: U.S. Geol. Survey Mon. 49, p. 101, 1907. % Cross, Whitman, Geology of the Denver Basin of Colorado: U.S. Geol. Survey Mon. 27, p. 230, 1896. % Marsh, O. C., Notice of new American Dinosauria: Am. Jour. Sci., 3d ser., vol. 37, p. 331, 1889. % Marsh, O. C., Notice of gigantic horned Dinosauria from the Creta- ceous: Am. Jour. Sei., 3d ser., Vol. 38, p. 173, 1889. % Marsh, O.C., The: skull of the gigantic Ceratopsidae: Am. Jour. Sci., 3d ser., vol. 38, pp. 501-506, 1889, 7 Cries, Whitman, Geology of the Denver Basin of Colorado: U. S. Geol. Survey Mon. 27, p. 231, 1896. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. . The statement that ‘“‘a distinct horizon” has been ‘traced nearly 800 miles” and that ‘‘it is marked every- where” by certain fossils would imply either that actual continuity had been proved or that the stratigraphic position of the fossil-bearing strata had been found to be clearly the same at numerous localities not far apart. But when Prof. Marsh made the above assertion the Denver region was the only one in which the position of the Ceratops-bearing beds had been established in complete sections, and here they were found to be separated from the typical Laramie below them by a great stratigraphic break. Moreover, none of the described fossils was found east of the mountains between the Denver Basin and Conyerse County, Wyo., a distance of 200 miles. As far, then, as the new fossils themselves are concerned, they prove either a great extension of the Arapahoe and Denver (post-Laramie of this report), or a distribution of the fossils in question beyond the limits of what may be properly termed one formation or horizon. In the following paragraph Cross added: In the original description by Prof. Marsh the fossils were said to have been obtained in ‘‘the Laramie of Wyoming” or ‘‘the Ceratops beds of Wyoming.” It is important to emphasize the fact that not one of the de- scribed species came from the typical Laramie strata of southern Wyoming or from their demonstrated equivalent. In succeeding years Marsh * continued to publish short papers on the Converse County material, but without a definite indication of locality, the only statement being that the fossils were ‘from the Laramie” or “from the Ceratops beds of Wyoming.’’ In February, 1893, however, Hatcher ® published a short paper, in which, for the first time, complete and definite information was given as to the: locality at which this wonderful vertebrate fauna had been found, as well as a description of the lithologic character and stratigraphic occurrence of the beds containing it, and also the reasons for regarding the horizon as. refer- able to the true Laramie. The typical area for the ‘ Ceratops beds,”’ which have since become classic, was stated to be in the northeastern portion of Converse County, now included in Niobrara County, which lies on the eastern border of Wyoming. These beds were also found in adjacent portions of Weston County. In his description of the deposits Hatcher said: 8 Marsh, O, C., Additional characters of the Ceratopsidae, With notice of new Cretaceous dinosaurs: Am. Jour. Sci., 3d ser., vol. 39, p. 418, 1890; The gigantic Ceratopsidae, or horned dinosaurs of North America: Idem, vol. 41, p. 167, 1891. 99 Hatcher, J. B., The Ceratops beds of Converse County, Wyo.: Am, Jour. Sci., 3d ser., vol. 45, pp. 135-144, 1893. 27 The Ceratops beds are made up of alternating sandstones, shales, and lignites, with occasional local deposits of lime- stones and marls. The different strata of the series are not always continuous, a stratum of sandstone giving place to one of shales, and vice versa. This is generally true of the upper two thirds of the beds. * * * The shales are quite soft and loosely compacted, composed mostly of clay with more or less-sand in places. The prevailing color is dark brown, but they are sometimes red or bluish. * * * The lignites occur in thin seams, never more than a few inches thick, of only limited extent, and with many impurities. * * * All the deposits of the ‘‘Cera- tops beds” of this region bear evidence of having been laid down in fresh waters. Among the invertebrate foasila found in them, only fresh-water forms are known. There is no evidence that marine or brackish waters have ever had access to this region since the recession of the former at the close of the Fox Hills period. As regards the stratigraphic position of the “Ceratops beds,’ Hatcher stated that the lowest exposed member of the section was identified by its numerous invertebrates as Pierre. Overlying this was an alternating series of sandstones and shales having an esti- mated thickness of 500 feet and containing, especially in the upper portion, an abundant invertebrate fauna pronounced to be typically Fox Hills. Above this series came the ‘“ Cera- tops beds,’”’ which had an estimated thickness of 3,000 feet. He added: All the beds of the entire section are conformable and bear evidence of a continuous deposition, from the Fort Pierre shales up through the Fox Hills sandstones and overlying fresh-water Ceratops beds. The Fort Pierre shales are not suddenly replaced by the Fox Hills sand- stones, but the transition is a gradual one, and it is impos- sible to say just where the one ends and the other begins. The same is true of the beds overlying the Fox Hills. The thin seam of hard sandstone, separating the fossil-bearing Fox Hills sandstones below from the very similar non- fossiliferous sandstone above, is here regarded as the dividing line between the Fox Hills and the Ceratops beds. But this decision, it must be admitted, is quite arbitrary, and the evidence in its favor is negative rather than positive. The only reason for placing the overlying 400 feet of nonfossiliferous sandstones in the fresh-water. series is the absence of fossils in them. In discussing the age of the “ Ceratops beds” Hatcher said: Owing to the fact that very few vertebrates had pre- viously been described from the typical Laramie, aa first defined by Mr. Clarence King, and the consequent lack of vertebrate forms known to have come from the Laramie for comparison with those found in the Ceratops beds, it must be admitted that the vertebrate fauna of the latter is, in itself, at present not sufficient proof to establish the Laramie age of the Ceratops beds. | 28 Hatcher concluded, however, that the “ Cera- |, tops beds” should be referred to the Laramie for the following reasons: 1. They conformably overlie the Fox Hills sandstones and contain both a reptilian and a mammal fauna, with decided Mesozoic affinities. * * * 2. They contain an invertebrate fauna comprising many | . forms identical with those already described from the typical Laramie, some of which are unknown except in the Laramie. 3. They immediately and conformably overlie the Fox Hills and show evidence of a continuous deposition through both series. In 1896 Hatcher published another paper dealing with the Converse County area, in | which he criticized in the severest manner Marsh’s statement that the “ Ceratops beds” had been traced some 800 miles along the east- ern flank of the Rocky Mountains. Hatcher showed that, with the exception of a single specimen from a doubtful locality, all the material studied by Marsh had been found in the Denver Basin, in Converse County, or in | the Judith River area. He said: These are very widely separated localities, and no attempt has ever been made to trace the continuity of the | strata from one to the other, nor is it at all probable that such an attempt would meet with success. Hatcher also questioned Marsh’s statements | that the ‘‘ Ceratops beds”’ are below the upper- most beds referred to the Laramie and that they rest on marine beds which contain in- ‘vertebrate fossils characteristic of the Fox Hills deposits. Although his comments were somewhat at variance with his former state- | ment, Hatcher continued as follows: Atmo place in the Converse County region do the true Ceratops beds, with the remains of horned dinosaurs, rest | upon true marine Fox Hills sediments; nor are the Ceratops beds in this region overlain by strata which could be re- | ferred without doubt to the Laramie. The writer has, ina paper published in the American Journal of Science of | February, 1893, stated that the Ceratops beds rest directly upon the Fox Hills series and has provisionally referred | the very similar series of sandstones and shales conform- ably overlying the Ceratops beds to the upper Laramie; but | it would doubtless be better to restrict the limits of the Ceratops beds to those strata in which horned dinosaurs | nearly as can be made out, the plants confirm occur, and to consider the underlying 400 feet of barren | sandstones as the equivalent of the Judith River beds. . Future investigations will doubtless show that the sand- stones, shales, and lignites overlying the typical Ceratops beds in Converse County should be referred to the Fort Union beds and not to the Laramie, as, according to Knowl- ton, the limited flora sent him now indicates. 1 Hatcher, J. B., Some loéalities for Laramie mammals and horned dinosaurs: Am. Naturalist., vol. 30, pp. 112-120, 1896. LARAMIE FLORA OF THE DENVER BASIN. In 1896 T. W. Stanton and I? spent several weeks in Converse County and also visited numerous localities in Colorado, Wyoming, and Utah, in a study whose object was stated as follows: As many of the supposed typical Laramie localities had been visited and studied by the various investigators | some years ago, before the recognition of the Arapahoe, Denver, and Livingston formations, it became a matter of | interest and importance to revisit these places and ascer- | tain, if possible, the bearing of the new data on the ques- | tions of their distribution, life, etc. In the discussion of the Converse County area in this paper several sections were given showing especially the Fox Hills and overlying “ Ceratops beds.” No fossils of any kind were detected in the 400 feet of sandstones men- tioned by Hatcher as occurring above the highest Fox Hills horizon, but just above these sandstones, in the basal portion of the “‘ Ceratops | beds,” though apparently below any remains of dinosaurs, a few brackish-water invertebrates | were detected. Particular attention was de- voted to the “ Ceratops beds,’”’ and numerous collections of invertebrates and plants were | listed. Regarding the interpretation of the inverte- brate fauna, the following statement was made: Of the 18 identified species in the above list just half occur at Black Buttes, Wyo., in or very near the bed that has yielded the saurian Agathaumas sylvestris Cope. The large proportion of identical forms and the general resem- blance of the entire faunas, especially in the large number and great differentiation of species of Unio, makes it reasonably certain that the Converse County and Black Buttes beds are on nearly thesame horizon. The evidence of the vertebrate fossils seems to trend in the same direc- tion. It will be shown later that the Black Buttes’ bed should be regarded as true Laramie, and consequently the series now under consideration is placed in the same category. ‘The plants, of which 25 forms were listed, were compared with the floras of various localities then supposed to be of Laramie age, and the conclusion was reached that “as the Laramie age of the Ceratops beds.” From the beds conformably overlying the highest dinosaur-bearing stratum 18 species of plants were obtained, and of the 10 named species 9 proved to be typical Fort Union 2 Stanton, T. W.,and Knowlton, F. H., Stratigraphy and aes tology of the Laramie and related formations in Wyoming: Geol. Soc. America Bull, vol. 8, pp. 127-156, 1907. Ss HISTORICAL REVIEW OF THE LARAMIE PROBLEM. formas, and hence these beds were regarded as of Fort Union age. For more than a decade after the studies resulting in the last-mentioned paper little or no active geologic work was done in the Converse County area, though the collecting of the remains of huge dinosaurs was continued from time to time by several persons. In the meantime, however, it had become known that the ceratopsian dinosaurs that were so abund- ant and characteristic in the Converse County ‘Tegion were by no means confined to that area. In 1907 Barnum Brown, of ‘the American Museum of Natural History, published a short paper? in which he recorded their abundant presence at many localities in Montana. This discovery was made in 1901 by William T. Hornaday, director of. the Bronx Zoological Garden, New York, while hunting in the bad- lands along Missouri River north of Miles City. Here Dr. Hornaday found a number of large bones, one of which was brought home and proved to be the tip of a horn of the large dinosaur Triceratops. From 1902 to 1906 Brown was engaged in exploring and collect- ing in Montana. The principal locality was in the vicinity of Hell Creek, a small stream entering the Missouri about 155 miles northwest of Miles City, but the same dinosaur-bearing beds were found on Yellowstone River at Castle Butte, near Forsyth, at Glendive, at Ekalaka, and at Hocket post office, from which they were thought (and have since been proved) to be continuous with similar dinosaur- bearing beds on the Little Missouri and near Grand and Moreau rivers in South Dakota. The dinosaur-bearing beds on Hell Creek, named the “Hell Creek beds” by Brown, are described as resting unconformably on Fox Hills beds of varying thickness, while above and repr esenting an uninterrupted continua- tion of them is a lignite series referred with question to the Fort Union. Above this series is the unquestioned Fort, Union with a char- acteristic flora. In discussing the correlation and age of the ‘‘ Hell Creek beds” Brown wrote as follows: . Lithologically the Hell Creek beds of Montana are similar in almost every respect to the Ceratops beds of Converse County, Wyo. Most genera and many species of verte- 29 brates and invertebrates are common to both deposits, while the faunal facies may be considereda unit. * * * They are therefore considered of contemporaneous depo- sition. In regard to the age of these beds he said: Strictly following King’s definition of the Laramie, neither of these deposits can be considered as such, for neither one represents a continuous sedimentation from the marine Fox Hills. They should therefore be grouped with the Livingston, Denver, and Arapahoe weds and may be considered post-Laramie. Although Brown considered the “Hell Creek beds” as post-Laramie and thus comparable to the Arapahoe and Denver formations in posi- tion, it is evident from the title of his paper that he still regarded them as Cretaceous. The year 1907 was also marked by the pub- lication of the monograph on the Ceratopsia by Hatcher and Lull. This comprehensive treat- ise was mainly the work of Hatcher and had been nearly completed at the time of his death, July 3, 1904. It was compiled and edited by Lull, who added a chapter on the phylogeny, taxonomy, distribution, habits, and environ- ment of the Ceratopsia. From this it appears that the localities then known for the so-called Taramie Ceratopsia were Black Buttes and Converse County, Wyo., and Hell Creek, Mont. The Denver localities were considered under a separate heading, and the statement was made that these beds (Arapahoe and Denver) had been “considered to be of post-Laramie age.”’ It was of course held that all the localities which had afforded the “Laramie Ceratopsia”’ belonged to the Cretaceous. In 1905 the United States Geological Survey began an investigation that had for its object the classification of the coal lands in the public-land States of the West, and this work has heen continued until the present time. ‘The plan has been to send a party, usually a small one, to survey a definite area for the purpose of ascertaining its coal resources and incidentally of procuring such data as time and opportunity offered on the general geology of the area. In this manner a large and impor- tant body of facts has been accumulated regarding the geology of regions or localities that might otherwise have remained obscure or imperfectly known for an indefinite period. 3 Brown, Barnum, The Hell Creek beds of the Upper Cretaceous of Montana: Am. Mus. Nat. Hist. Bull., vol. 23, p. 823, 1907. 85344—22—3 4 Hatcher, J. B., and Lull, R. S., The Ceratopsia: U. S. Geol. Survey Mon. 49, 1907. 30 One of the first of these so-called coal reports was made by A. ©. Veatch * for a large area in southwestern Wyoming, though the coal report was expanded into a complete consideration of the geology and resources of the region covered. +(See p. 67.) In 1906 this work was systematized and prosecuted in all the Rocky Mountain States, though the results were not published until 1907. In the present connection the report by A. G. Leonard * on the coal fields of parts of Dawson, Rosebud, and Custer counties, Mont., is of interest. This was really hardly more than a reconnaissance report on a large area lying mainly between Missouri and Yellow- stone rivers and extending from Fell Creek eastward to the State line. Four geologic formations were recognized in this field— Pierre, Fox Hills, “dinosaur-bearing beds”’ not otherwise named, and Fort Union. In some places, as at Glendive, the Fox Hills was supposed to be absent and the overlying dinosaur-bearing beds rested directly on the Pierre. The dinosaur-bearing beds were de- scribed by Leonard as follows: Heretofore all the beds above the marine Pierre shale have been regarded as belonging to a single formation ’ which carries the lignite and subbituminous coal beds of this field. These rocks have been called at various times “Laramie” and ‘‘Fort Union,” on the supposition that they compose but a single formation. The work of the last year, however, has shown that at Glendive the rocks above the Pierre shale apparently comprise two forma- tions. * * * The beds are strikingly similar to the dinosaur-bearing beds {[=‘‘Hell Creek beds” of Brown] on Hell Creek, and presumably they are identical. The Fort Union was everywhere conform- ably above the “dinosaur-bearing beds”’ and was described as ‘‘readily distinguished by the light-gray and buff color of its beds.” The economic coal investigations, which have a more or less direct bearing on the present problem, were continued in 1907, and the re- sults were published in 1909.’ A. G. Leonard and Carl D. Smith reported on the Sentinel Butte lignite field, in North Dakota and Mon- tana, where they found only the Fort Union formation. Arthur J. Collier and Carl D. Smith reported on the Miles City coal field, in Montana, where also only the Fort Union was recognized, though the lower 500 feet of beds 5 Geography and geology of a portion of southwestern Wyoming, with special reference to coal and oil: U. S. Geol. Survey Prof. Paper 56, 1907. 6 U.S. Geol. Survey Bull. 316, p. 194, 1907. 7U. 8S. Geol. Survey Bull. 341, 1909. LARAMIE FLORA OF THE DENVER BASIN. [the equivalent of the “‘dinosaur-bearing beds” of the Glendive section] was described as show- ing a marked lithologic difference. In the main only the Fort Union was described by L. H. Woolsey in his account of the Bull Mountain coal field, in Montana, though he mentioned briefly certain beds on Dean Creek and an olive- green shale which he regarded as being beneath the Fort Union. In the report on coal near the Crazy Mountains, Mont., R. W. Stone rec- ognized the marine Cretaceous section as de- fined by Stanton and Hatcher for the Judith River area (see p. 77), and above this, in as- cending order, the Laramie, Livingston, and Fort Union formations. In his report on the Red Lodge coal field, Mont., E. G. Woodruff referred the whole visible section of 8,000 feet to the Fort Union, as did J. A. Taff the coal-bearing section in the Sheridan coal field, Wyo. On the southwest side of the Big Horn Basin of Wyoming Woodruff identified as Laramie (?) a series of sandstones and shales overlying the Montana group. This series was said to contain invertebrates belonging to a fauna characteristic of the +‘ Ceratops beds.”’ Woodruff said: As the stratigraphic position of these beds [‘ Ceratops beds”] is not definitely determined, the name Laramie is applied because the Laramie formation occupies a position in the geologic column between the Montana and Fort Union, * * * The name, however, should not be con- sidered as indicative of a positive correlation with beds of Laramie age to the south. The Laramie was also tentatively recognized by C. W. Washburne on the northeast side of the Big Horn Basin, though-the evidence aside from position was not very clearly stated. Up to 1909 there had been no formal, pub- lished protest against the reference of the “Ceratops beds” to the Cretaceous, although several writers had indicated that in certain areas the stratigraphic relations of the dinosaur- bearing beds were such that they were at vari- ance with the original definition of the Laramie. In this year I published a paper® under the title ‘The stratigraphic relations and paleon- tology of the ‘Hell Creek beds,’ ‘ Ceratops beds,’ and equivalents, and their reference to the Fort Union formation,” in which the following was given as the thesis: The present paper deals with the extensive series of fresh-water deposits of the Northwest, comprising what is 8 Knowlton, F. H., Washington Acad. Sci. Proc., yol. 2, pp. 179-238. 1909. HISTORICAL REVIEW OF THE LARAMIE PROBLEM, here considered as the Fort Union formation. It is shown that the Fort Union embraces more than has been com- monly assigned to it. Conformably below the beds by some geologists considered as the true Fort Union occur dark-colored sandstones, clays, and shales, which have often been incorrectly referred to the Laramie or its equiva- lent but which are stratigraphically and paleontologically distinct from the Laramie, and the contention is here made that these beds, which include the ‘Hell ‘Creek ‘beds’? and so-called ‘‘somber beds” of Montana, the ‘‘Ceratops beds” or ‘‘Lance Creek beds” of Wyoming, and their stratigraphic and paleontologic equivalents else- where, are to be regarded as constituting the lower member of the Fort Union formation and are Eocene in age. In this paper a brief historical summary of the Fort Union formation was followed by an account of its areal distribution and lithologic character, in which I held that it may be divided into two members. The areal distri- bution and paleontologic contents of the lower or dinosaur-bearing member were given as completely as available facts then warranted. The distribution included the following areas in Montana: Hell Creek, Miles City and vicin- ity, Forsyth, Custer, Bull Mountains, Mel- ville, Red Lodge, Glendive, and from Glendive to Medora, N. Dak. Several areas in North Dakota were discussed, as well as a probable area (since confirmed) in northwestern South Dakota. Thence the formation was traced to Weston County, Wyo., and thence northward to connect with the area at Miles City, Mont. Other areas in Wyoming were Converse County, a great region east of the Big Horn Mountains, and the Big Horn Basin. Thus it was shown that the ‘“Ceratops beds,” originally supposed to occur only in Converse County, Wyo., really occupy a vast area distributed over four great States. The essential results claimed in this paper were sufficiently set forth in the “summary and conclusions,”’ as follows: 1. The Fort Union formation is a fresh-water Tertiary formation of wide areal extent, mainly east of the Rocky Mountains, ranging from Wyoming and western South Dakota over western North Dakota, eastern and central Montana, the central Canadian Provinces, and reaching the valley of the Mackenzie River. 2. It is shown that the Fort Union formation may be separated into two members on lithologic grounds. The present paper deals only or largely with the stratigraphy and paleontology of the lower member, which includes the “Hell Creek beds” and so-called ‘‘somber beds” of Montana and the ‘‘Ceratops beds” of Wyoming. 3. The areal distributiog, of the lower member is traced in Montana, North and f£outh Dakota, and Wyoming, 31 and its probable extension in other areas is indicated. Complete lists of the fossil plants are given by localities for each of the areas. 4. 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. 5. It is shown that the beds under consideration, being above an unconformity, can no longer be considered as a part of the ‘conformable Crevaneous series” and hence are not Laramie. 6. It is shown that the two members of the Fort Union, although usually distinct lithologically, can not be sepa- rated structurally, sedimentation having been uninter- rupted, except locally. 7. The paleontological elements of the lower members are considered at length, beginning with the plants. It is shown that of the 84 known species, 61 are common to the upper member, and only 11 species to the Laramie of Colorado, while 15 species are common to other American Eocene, and 9 species to the Miocene. The Eocene age of the Fort Union is fixed by tying its flora to that.of vari- ous Old World beds of known Eocene position. 8. The invertebrate evidence is shown to be in sub- stantial accord with that of the plants, there being only 4 of the 49 species common to the Colorado Laramie. All, with a single possible exception, are fresh-water forms. 9. It is shown that the vertebrates afford no positive evi- dence of Cretaceous age. That the dinosaurs exhibit Cretaceous affinities is not denied, since, being without known descendants, it is possible to compare them only with their progenitors. It has been proved beyond question that they suryived the profound orogenic move- ment and attendant physical break at the top of the Laramie in the Denver Basin of Colorado and lived on in Arapahoe and Denver time, and it is shown that in the areas considered in this paper they passed over a similar erosional interval and are found in association with the Fort Union flora, which is of Eocene age. 10. The mammals of the lower Fort Union show very little relationship with Jurassic or Cretaceous forms but find their closest affinities with those of the Puerco and Torrejon, which are of acknowledged Eocene age. 11. The chelonians are shown to be of little value in their bearing on the age of the lower Fort Union, especially when compared with the Judith River forms, which are evidently in confusion. 12. It if held that the line between Cretaceous and Tertiary should be drawn at the top of the true Laramie. 18. The final conclusion is reached that the beds here considered (‘‘Hell Creek beds,’’ ‘‘somber beds,”’ ‘‘Ceratops beds,” “Laramie” of many writers) are stratigraphically, structurally, and paleontologically inseparable from the Fort Union and are Eocene in age. The above-mentioned paper was followed almost immediately by a paper by T. W. Stanton,’ entitled ‘‘The age and stratigraphic 9 Washington Acad. Sci. Proc., vol. 2, pp. 239-293, 1909. 32 relations of the ‘Ceratops beds’ of Wyoming and Montana.” The thesis of this paper was stated as follows: The purpose of the present paper is to show that some of the data already used in the discussion [by Knowlton, Cross, and others] are capable of a different interpretation and to call attention to some additional facts which ought to be fully considered before a final verdict is reached. All are agreed that the strata in question are near the boundary between Cretaceous and Tertiary. My opinion is that the greater weight of evidence places them on the Cretaceous side. Under the head of ‘‘local stratigraphy and paleontology” Stanton reviewed a number of the areas in Wyoming and Montana con- sidered in my paper and set forth his own field observations and interpretation of the stratigraphic and paleontologic conditions. In summarizing these data Stanton said: It has been shown that, within the large area considered, the “‘ Ceratops beds” with the Triceratops fauna are always pretty closely associated with the uppermost 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 dino- saurian remains have been found, and in the Fish Creek, Mont., region this overlying series also contains primitive mammals related to those of the Puerco and Torrejon faunas. Throughout a large part of the area noevidence of an unconformity beneath the “‘ Ceratops beds” has been found, while higher in the section unconformities have been demonstrated or suggested at a number of places. Unconformities have been reported below the “‘ Ceratops beds” on Hell Creek, Mont., on the Little Missouri, in North Dakota, and in Weston County, Wyo., but in none of these cases has any proof been furnished that the erosion interval is important. The conclusions reached in this paper are given as follows: In the interior region of North’ America the formations between the uppermost marine Cretaceous and the Wasatch together constitute a real transition from the Cretaceous to the Teritary. Notwithstanding the fact that there are several local unconformities at various horizons and perhaps some of more general distribution, there is no conclusive evidence that any one of these represents a very long period of erosion not represented by sediments elsewhere in the region. 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 this correlation. : The “‘ Ceratops beds” are of Cretaceous age as decided _by stratigraphic relations, by the pronounced Mesozoic LARAMIE FLORA OF THE DENVER BASIN. character of the vertebrate fauna with absence of all Tertiary types, and by the close relations of the inverte- brate fauna with the Cretaceous. The relation 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 equiva- lents of the Laramie, Arapahoe, and Denver formations of the Denver Basin. Hay * also published a paper in 1909 on one position and age of the ‘“Ceratops beds,” in which, after comparing the fauna of these beds with ifs of the Judith River, Puerco, Torre- jon, and several European formations, he con- cluded as follows: : 1. The answer that the writer would give to the ques- tion at the head of this paper is that the Lance Creek beds belong to the Upper Cretaceous. 2. In the Upper Cretaceous ought to be included also the Puerco and not improbably. also the Torrejon and Fort Union. ‘ 3. In case of a conflict between the evidence furnished by the flora and the fauna of the Lance Creek beds and those of the Fort Union respectively, the evidence ob- tained from the fauna is to be preferred, as being part of a more complete and better understood history. Present knowledge regarding plants seems to indicate that they were precocious, having reached something like their present stage of development long before mammals at- tained anything like their present stages of differentia- tion. There are also indications that the floras of. the western world were, during the Cretaceous, considerably in advance of those of Europe. : 4, Even if it were concluded that the Fort Union be- longs to the Tertiary, and that the fauna and flora of the Lance Creek epoch are more closely related to those of the Fort Union than they are to those of the Judith River, it does not follow that the Lance Creek epoch must be included in the Tertiary. A quarter before midnight on Monday is much nearer to Tuesday than it is to the pre- vious 6 o’clock; nevertheless, it is not yet Tuesday. The work of the United States Geological Survey in classifying the coal lands was continued in 1908, though the results of this year’s investigations were not published until 1910.11 It is noteworthy that in the areas falling within the scope of the present review the Fort Union has come to be placed un- qualifiedly in the Tertiary. In the volume cited R. W. Richards has a paper under the title ‘‘The central part of the Bull Mountain coal field, Mont.,”’ in which the stratigraphic relations are set forth 3 in the following table: T : 10 Hay, O. P., Where do the Lance Creek (‘‘ Ceratops’’) beds belong— in the Cretaceous or in the Tertiary?: Indiana Acad. Sci. Proc., vol. 25, 1909. U.S. Geol. Survey Bull. 381, 1910. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. Stratigraphy of the central part of the Bull: Mountain coal field, Mont. Thick- ness » (feet). System. Formation. Description. Yellowish sandstones and shales __inter- stratified with lignite beds. Somber-colored shale and coarse yellow 4 sandstones with beds of carbonaceous sand- stone and shale. Alternating gray sand- stones and clay shales, with thin coal beds. ‘Gray to brown shales and clay. Tertiary...) Fort Union.| 1, 650 OO arama teeters * 200-300 Laramie (?)| 1, 480 Cretaceous. Bearpaw. .. ' The Laramie (?) was regarded as the equiv- alent of the “somber beds” of the Miles City field. The Buffalo coal field, Wyo., was described in this bulletin by H. S. Gale and C. H. Wege- mann. In this area the dinosaur-bearing beds were referred to the so-called Piney formation, which was said to be pre-Tertiary or Cretaceous [both terms are used in the report], though some doubt was expressed as to whether this designa- tion would prove to be correct. In 1910 T. W. Stanton ” published a short paper dealing with this subject and recording new field data from areas in the Dakotas and eastern Wyoming. The term Lance formation, which has now come into such general usage, was here published for the first time and was specifically stated to be a substitute for the old terms “‘ Ceratops beds,”’ “ Lance Creek beds,” and equivalents. Of the three areas discussed in this paper the one first considered was the Standing Rock and Cheyenne River Indian Reservation, or the region between Grand and Cannonball rivers in North and South Dakota. In this area attention was directed principally to the Fox Hills sandstone and its contrast with overlying beds, and a number of sections were given, together with lists of the inverte- brates found. Stanton said: .At the top of the Fox Hills sandstone with its purely marine fauna there is a rather thin but widely distributed brackish-water bed, which contains Ostrea, Anomia, Cor- bicula, Melania, etc., in great abundance. The zone in 12 Fox Hills sandstone and Lance formation (‘‘ Ceratops beds’’) in South Dakota, North Dakota, and eastern Wyoming: Am. Jour. Sci., 4th ser., vol. 30, pp. 172-188, 1910. 33 which this fauna occurs varies in thickness from 3 or 4 feet up to 40 feet and is lithologically very similar to the under- lying marine beds, but its base is irregular at many places and shows channeling and other evidences of erosion. It was therefore regarded by the field geologists as the basal member of the overlying Lance formation resting uncon- formably on the Fox Hills. In the study of this brackish- water bed evidence was found at several localities, dis- tributed over a considerable area, that there is a distinct transition without a break of any importance between the marine Fox Hills sandstone and the brackish-water de- posit. The paleontologic evidence consists of distinctive Fox Hills species belonging to such marine genera as Scaphites, Lunatia, and Tancredia, found directly associated in the same bed with the brackish-water forms and occur- ring with them in such a way that they must have lived together or near each other and been embedded at the same time. The second area included the valley of the Little Missouri from Marmarth to Yule, N. Dak. The point emphasized with reference to this area was the finding of an oyster bed some 500 feet above the base of the Lance formation ‘and above all the dinosaurs that have been found in the region. The Lance Creek area in Converse County, Wyo., which had been reexamined in company with M. R. Campbell and R. W. Stone, was the third area considered. Of this area Stanton said: Our principal contribution to the knowledge of the stratigraphy of the area was the discovery that the marine Fox Hills deposits extend about 400 feet higher than had previously been determined, and that nonmarine coal- forming conditions were temporarily inaugurated here before the close of Fox Hills time. In conclusion Stanton wrote: The three areas discussed in this paper, taken together, tell a story of gradually changing conditions near the end of the Cretaceous, when the uplift of the Rocky Mountain region was draining the interior sea. The uplift was not uniform nor continuous, and the ‘emergence above sea level could not have been simultaneous for all localities throughout the region. * * * The bearing which the facts here presented have on the Laramie problem is self- evident. If it is true that there is a transition with prac- tically continuous sedimentation from the Fox Hills sand- stone into the Lance formation in the region discussed, then the Lance formation includes or forms part of the Laramie. The first published official statement showing that the discussion concerning the age of the Lance formation was having its effect is to be noted in a short report on the eastern part. of the Bull Mountain coal field, Mont., by C. T.- Lupton." Here for the first time the Lance 1% U.S. Geol. Survey Bull. 431, p. 163, 1911. 34 formation was classed as ‘‘Cretaceous or Ter- tiary.” In May, 1911, I published a short paper “ entitled ‘‘Further data on the stratigraphic position of the Lance formation (‘Ceratops beds’),” which gave the results of the work of the two field seasons that had intervened since the publication of my first paper on this sub- ject. What was then thought to be the most important result recorded was the finding in Carbon County, Wyo., of the remains of Tri- ceratops in the so-called ‘‘Upper Laramie” of Veatch, above the supposed profound uncon- formity as described and mapped by him. After describing this occurrence I made the followingstatement: , Since, with the exception of their occurrence in the post-Laramie deposits of the Denver Basin, the remains of Triceratops have never been found outside the Lance formation, the finding of Triceratops at this point is of far-reaching importance. It shows that not only are the beds containing them above more than 6,000 feet of “Laramie” rocks (the basal portion of which is almost certainly of Fox Hills age), but also that they are separated from the ‘‘Laramie” [‘‘Lower.Laramie”] by an uncon. formity, which, according to Veatch, is profound and has involved the removal of perhaps as much as 20,000 feet of sediments. This would seem effectively to dispose of the contention that the Lance formation [‘‘ Ceratops beds’’] is the equivalent of the Laramie. Another part of this paper was an important contribution of several pages by W. R. Calvert, on the stratigraphic relations in the old Stand- ing Rock and Cheyenne Indian Reservation, in South and North Dakota, as observed by him and by the parties under his charge. In this contribution particular attention was devoted to the Fox Hills and the overlying Lance formation. Calvert said: ‘‘As a-result of field study by Pishel, Barnett, and the writer, it seams certain that the line between the Fox Hills sandstone and the' Lance formation is marked by an unconformity.” Calvert pointed out that the Fox Hills has a maximum thick- ness of 200 feet in this region, but it was found to vary greatly, and in some places it was entirely absent, the Lance formation resting on the Pierre. Angular as well as erosional dis- cordances between the two were noted. Calvert was of the opinion that the reported occurrence of Fox Hills invertebrates in the lower part of the Lance 14 Jour. Geology, vol. 19, pp. 358-376, 1911, LARAMIE FLORA OF THE DENVER BASIN. may be looked at from two divergent points of view. Be cause Fox Hills fossils occur in the lignitic shales at the base of the ‘“‘somber beds” and mingled with the brackish- — water types of the Lance formation is not necessarily proot positive that the various faunas lived at the same time, for if the deposition of the Fox Hills was followed by a definite erosion interval, what is more probable than that in the deposition of succeeding strata fossil shells would be eroded from the marine beds and carried into the chanhels, there to mingle with the then living brackish-water fauna of the Lance formation? c The conclusions reached in this paper were in part as follows: It has now been demonstrated that the Lance formation is everywhere followed conformably by the acknowledged Fort Union—that is to say, sedimentation from one to the other was continuous and uninterrupted. The unconformable relations between the Lance formation and underlying formations having been demonstrated at so many points, it could only be concluded that this unconformity is undoubtedly one of importance, and this would seem to dispose of the contention that the Lance, Arapahoe, and Denver formations may be mere ‘‘phases of Laramie.’ * * * ‘This point becomes more clearly than ever the logical point at which to draw the line be- tween Cretaceous and Tertiary. , Later in 1911 I published a short note * under the caption ‘‘Where are the Laramie dinosaurs?”’- In this note the facts regarding the relations between the Laramie and Lance formations, as recorded in previous papers, were briefly set forth, and I concluded with the following paragraph: The vertebrate paleontologists continue to refer to the “Ceratops beds” as the “Laramie,” the ‘“‘Laramie Creta- ceous,”’ etc., as though nothing had been ascertained re- garding their position since they were named 25 years ago. Ii there is valid evidence to show that the Lance formation (‘‘Ceratops beds”) is the equivalent to the Laramie in whole or in any part, it would be welcome. If there is a known locality where dinosaurs (Ceratopsidae) occur in the true Laramie, information concerning it should not longer be withheld. _ The report on the work of the United States Geological Survey on mineral fuels, for the year 1910, published in 1912,* contains many short papers and preliminary reports relating to Rocky Mountain areas, here under consider- ation. In these papers, by Pishel,!’ Calvert," 16 Science, new ser., vol. 34, p. 320, 1911. 16 U.S. Geol. Survey Bull. 471, 1912. u Pishel, M. A., Lignite in the Fort Berthold Indian Reservation, N Dak.: Idem, p. 170. 8Calvert, W. R., Geology of certain lignite fields in eastern Mon- \ tana: Idem, p. 187. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. ’ 35 Bowen,” Herald, Hance, Stebinger,”| In the first paper 2° the following was given Beekly,? Wegemann,% Winchester, and | as the thesis: others, the Lance formation was uniformly classed as ‘‘Cretaceous or Tertiary.” It is not necessary to refer to these papers in detail, except to that of Calvert, in which he recorded certain facts of importance relating to a large area in eastern Montana. He divided the Lance formation of this area into two parts— a lower sandstone member, immediately over- lying the Pierre and named the Colgate sand- stone member, and an upper or undivided portion. As regards the line between the Lance and the overlying Fort Union he said: In the area mapped the upper limit of the Lance forma- tion can not be based on lithologic grounds but must instead be dependent upon the occurrence of fossil Cera- topsia bones. In the area treated in this report the highest horizon at which these bones were found is just above the lower persistent lignite bed, but there is certainly nothing in the character of the overlying strata to suggest that similar bones do not occur therein up through a strati- graphic distance of perhaps 500 feet. * * * Asaresult of these conditions no attempt is made on the index map or on the maps of the various areas treated in this report to differentiate the Lance formation from the overlying strata described in connection with the Fort Union forma- tion. * * * Jn other words, the area bounded on one side by the contact between the Pierre shale and the ‘Colgate sandstone member and on the other side by the outcrop of the lowest persistent lignite bed represents the distribution of the Lance formation as mapped in this field. In this connection, however, it can not be emphasized too strongly that the upper limit adopted is merely suggestive, as the finding of Triceratops bones higher in the section will necessitate an upward extension of the formation. At the meeting of the Paleontological Society in Princeton, N. J., December 31, 1913, and January 1, 1914, there was held a symposium on the ‘Close of the Cretaceous and opening of Eocene time in North America,’”’ which was briefly introduced by Henry Fairfield Osborn, and in which Messrs. Knowlton, Stanton, Brown, Matthew, and Sinclair participated. 19 Bowen, C. F., The Baker lignite field, Custer County, Mont.: Idem, p. 202. 20 Herald, F. A., The Terry lignite field, Custer County, Mont.: Idem, p. 227. 21 Hance, J. H., The Glendive lignite field, Dawson County, Mont.: Idem, p. 271. 2 Stebinger, Eugene, The Sidney lignite field, Dawson County, Mont.: Idem, p. 284. 23 Beekly, A. L., The Culbertson lignite field, Valley County, Mont.: Idem, p. 319. 2 Wegemann, C. H., The Sussex coal field, Jobrson, Natrona, and Converse counties, Wyo.: Idem, p. 441. 25 Winchester, D. E., The Lost Spring coal field, Converse County, Wyo.: Idem, p. 472. It is proposed to show that the dinosaur-bearing beds known as ‘‘Ceratops beds,” ‘‘Lance Creek beds,” Lance formation, ‘‘Hell Creek beds,’’ ‘“‘somber beds,’’ ‘‘lower Fort Union,” Laramie of many writers, ‘Upper Laramie,”’ Arapahoe, Denver, Dawson, and their equivalents are above a major unconformity and are Tertiary rather than Cretaceous in age. The evidence was presented under the headings stratigraphic, paleobotanic, dias- trophic, European time scale, vertebrates, and invertebrates. In the discussion of strati- graphic evidence it was held “ that the dinosaur- bearing beds above mentioned are separated from underlying beds by a major uncon- formity which makes the logical line of separa- tion between Cretaceous and Tertiary.” The evidence bearing on the occurrence of this un- conformity was traced throughout North and South Dakota, Montana, Wyoming, Colorado, and New Mexico and was demonstrated in a number of ways, including angular and ero- sional discordance, as well as faunal and floral differences. The paleobotanic evidence was naturally presented in extenso. It was shown that the floras in the beds immediately below and above the line of the unconformity comprise about 350 species in the lower beds (Vermejo, Laramie, Montana, etc.) and over 700 species in the upper beds (Raton, Dawson, Arapahoe, Denver, Lance, etc.) but that they have only 21 or 22 species in common, showing “that more than 90 per cent of the Cretaceous flora was wiped out by the disturbance attending this diastrophic movement.”’ In the Raton Mesa region of Colorado and New Mexico the beds immediately above the unconformity have been named the Raton formation and contain a flora of 148 species, only 4 of which are common to the underlying Vermejo, which is below the line of the uncon- formity. The Raton flora was correlated with those of the Wilcox group of the Gulf coast and of the Dawson, Arapahoe, and Denver formations to the north. The correlation was carried from the Denver Basin of Colorado through North Park and into Carbon County, Wyo., where the ‘‘Upper Laramie” of Veatch 26 Knowlton, F. H., Cretaceous-Tertiary boundary in the Rocky Mountain region: Geol. Soc. America Bull., vol. 25, pp. 325-340, 1914. 36 : was held to be of the same age as the Lance formation of Converse County, Wyo., and thence throughout Montana and the Dakotas. “The Lance flora embraces about. 100 named and described species. Of these 100 species, over 75 are typical Fort Union species that have never been found in older beds and most of them only in the Fort Union.” The Fort Union was said to be of acknowledged Eocene age. In discussing the European time scale it was shown that (1) The Cretaceous and Tertiary systems were originally established on a physical basis, and the exact line of separation between them was determined by the struc- ture; (2) after more than a century, during which the several lines of evidence have been tested, the last authori- tative word on the European standard is to the effect that the structure is the determining factor in separating them, and that even dinosaurs that have been appealed to so often as proof of Cretaceous age did not end with the Cretaceous. The vertebrate and invertebrate evidence was briefly considered. In conclusion, the thesis given at the beginning of the paper was repeated and considered as follows: Evidence, believed to be competent, has been pre- sented in support of this view from the side of stratigraphy, _ diastrophism, and paleobotany, and what is thought to be the weakness and insufficiency of the vertebrate and invertebrate evidence has been pointed out. The verte- brate paleontologist would place the Cretaceous-Tertiary line at the highest horizon at which dinosaurs have been found, notwithstanding the fact that this is ‘a variable boundary, unattended by structural or diastrophic action. The invertebrate paleontologist would place this line at the highest point where marine invertebrates of Cannon- ball type occur. The paleobotanist would place the line at the lowest horizon at which Tertiary plants have been found, which corresponds with the structure. The paleontologists are not in accord. What, then, is to be the court of final appeal? There is but one answer: Structure resulting from diastrophism. The evidence from these sources supports the thesis. The second paper of the symposium, by T. W. Stanton,?? began with a discussion of the typical Cretaceous and Eocene of western Europe, in which it was held that the Anglo- Parisian basin “can perhaps with' justice be considered the typical area of both Cretaceous and Eocene.” It was shown that here there is a well-marked structural break, as well as a strong faunal break, and it is of course easy to distinguish between them, but that in other 2% Boundary between Cretaceous.and Tertiary in North America, as indicated by stratigraphy and invertebrate faunas: Geol. Soc. America Bull., vol. 25, pp. 341-354, 1914. LARAMIE FLORA OF THE DENVER BASIN. ” areas (Denmark, Belgium, center of Paris | Basin, etc.) there are deposits, in part marine and in part continental, which seem to belong between the highest Cretaceous and the lowest Eocene represented in England. These intermediate deposits have been called Danian, Montian, and .other more local names and have been assigned by some geolo- gists to the Cretaceous, by others to the Tertiary, and by still others part to the Cretaceous and part to the Terti- ary. * * * | All will agree, I think, that when two contiguous systems as originally defined are separated by an un- conformity, if there is other evidence of a break in sedi- mentation, it is probable that intermediate deposits will be found in some part of the world, and that when found, if they are subordinate in characten, they should be as- signed in each case to the system to which they are most closely related. In discussing the contact between marine Cretaceous and marine Eocene in North America, Stanton pointed out that In America, as in England, wherever marine Cretaceous is directly overlain by marine Eocene, there is no diffi- culty in recognizing the boundary between them,;and there is no controversy concerning the boundary. * %*y,* In the Interior Province, including the Great Plains and Rocky Mountain region, conditions were different. The Upper Cretaceous sea during the Colorado epoch covered a large part, if not the whole, of the province, and by the end of the Cretaceous it had entirely retreated from the area; but the Bocene sea did not return into this province at all. Instead of marine deposits great continental deposits were formed, beginning in the Cretaceous and continuing with many interruptions and with increasing restriction of areas throughout Tertiary time. As regards the evidence of land areas in the Rocky Mountain region during the Cretaceous, Stanton wrote as follows: /she idea has sometimes been expressed that this was a period of quiet and universal submergence for the province, with no land masses within it until the end of the period, when the whole area was lifted above sea level by a single movement. There are many facts opposed to this view— so many that they form convincing evidence that at several times during the period there were differential movements which brought previously submerged local areas above sea level. The greatest submergence of the sea, and pre- sumably the deepest submergence, seems to have been near or after the middle of the Colorado epoch; but even at that time it is probable that there were large islands. Local variations in thickness and character of sediments bespeak the nearness of land at some localities. As examples in support of this contention were given the Datil Mountain area in western New Mexico, where a land flora was developed in the Colorado; the Mesaverde formation of Colorado, Wyoming, Utah, etc., which shows extensive coal deposits; various coal fields of HISTORICAL REVIEW OF THE LARAMIE PROBLEM, the Colorado epoch in Utah and Wyoming; coal and fresh-water deposits in the Eagle and Judith River formations; and finally, the volcanic activity which furnished material for the Livingston formation jn the area about the Crazy Mountains in Montana. Stanton also devoted several pages to the consideration of the Lance formation, including its distribution and general character, its development in North and South Dakota, and particularly the marine member and its fauna. Regarding this fauna he said: In my opinion, the invertebrates from the marine mem- ber of the Lance belong to a Cretaceous fauna. This is indicated both by their close relationship with the Fox Hills fauna and by the known paleogeographic facts of the late Cretaceous and the Eocene. The fauna contains a, number of species identical with Fox Hills forms, others that are closely related, a few that were ascribed to the Fox Hills but apparently were actually collected by the early explorers from beds now assigned to the marine mem- ber of the Lance, and a considerable number of new species, which, so far as known, do not occur outside of the marine member. * * * The fauna lacks a number of common Fox Hills species and contains a considerable proportion of new forms, so that it may be called a modified Fox Hills fauna. The conclusions reached are stated as follows: In my opinion, therefore, the conclusion is justified that the Cretaceous period did not end in the interior province until the sea had completely retreated from the province, and that the Lance formation should be assigned to the Cretaceous. The final retreat of the Cretaceous sea from the interior province was doubtless associated more or less closely with local. orogenic movements which caused active erosion to begin or to increase in various areas; but in other areas within the province the products of this erosion were laid down as terrestrial deposits, which taken together practi- cally bridge the gap between Cretaceous and Tertiary. The boundary between the two systems in such areas is not marked by an important break caused by general diastrophism, because the breaks and discordance and erosion intervals in an area of continental deposition are not dependent on the same conditions that cause the major breaks in marine sediments. Even if it be true that there was a world-wide movement at the close of the Cretaceous which caused a break between marine Creta- ceous and marine Eocene in all the areas where such sediments are now accessible, such a movement would not necessarily affect the accumulation of continental deposits of detrital material in an area already above sea level, and in this case apparently it did not affect it. On the other hand, terrestrial deposits are characteristically and necessarily irregular, and the importance of breaks and unconformities in them must therefore be tested with great care, using all kinds of available evidence. The Lance formation is believed to be Cretaceous on account of its intimate stratigraphic relation with the un- derlying marine Cretaceous, 9n account of the close rela- 37 tionship of its vertebrate and nonmarine invertebrate faunas with Cretaceous faunas, and on account of the occurrence in one area of a marine Cretaceous fauna within the formation. This marine Cretaceous invertebrate fauna is held to establish the Cretaceous age of the plants which occur in the beds beneath it, in spite of the fact that these plants are said to belong to Eocene species. In other areas where the Lance formation does not include a marine member but has a thicker development of strata, with a large vertebrate fauna of Mesozoic types, it is a fair infer- ence that the whole formation, with its contained flora, is also of Cretaceous age. If, then, the Lance flora is in fact a Cretaceous flora, notwithstanding its close relationship with Eocene floras, it is obvious that.the correlation of other formations with known Eocene formations on the evidence of fossil plants alone is open to serious question. In the case of the Denver and Arapahoe formations such a correlation is directly opposed by the evidence of the ver- tebrate fauna, which allies them closely with the Lance formation. In the contribution of Barnum Brown ” to ane symposium he stated that he had been ‘continuously engaged since June, 1900, in the exploration of the geology, flora, and fauna of three great formations which in their animal and plant life bridge over the passage from Cretaceous to Eocene time, as determined by the comparison with the life of the same epochs in Europe.” These, formations are ‘Hell Creek formation of northern Montana; series embracing in descending order Paskapoo, Ed- monton, Fort Pierre (upper), Belly River (in- tercalation), Fort Pierre: (lower) of Red Deer River, Alberta; Ojo Alamo formation of north- . ern, New Mexican: Lance Creek formation of Converse County, Wyo.” In a former paper Brown had described his “Hell Creek beds” as resting unconformably on the underlying Fox Hills, but this statement he now desired to modify. He described a number of localities in which “these marine beds [Fox Hills] have been eroded in places, sometimes to a depth of 10 feet, before the succeeding massive sandstone of the fresh- water ‘Lance’ was deposited.”” This break, he ana is evidently of local erosional character,” as ‘the strata are, however, in all cases Seal ‘to the hedding planes of the suc- ceeding sandstones.’ The Paskapoo and Edmonton formations as exposed along Red Deer River, Alberta, were described at some length. The conclu- sion was reached that the Paskapoo has a mammal fauna in which “ the multituberculates 28 Cretaceous Eocene correlation in New Mexico, Wyoming, Montana, Alberta: Geol. Soc. America Bull., vol. 25, pp. 335-380, 1914. 38 and trituberculates are unmistakably those of the Lance, but the placental mammals have not been found in the Lance and appear to belong to the Paleocene groups of mammals,” while the invertebrates “are suggestive of Fort Union rather than earlier forms.”’ The Edmonton formation, although containing a flor’, at least in the upper part, that is un- doubtedly indicative of Fort Union age, was concluded to be Cretaceous and older than Lance on account of the presence of a plesiosaur (Leurospondylus), a marine reptile Mesozoic age,” above the plants. concluded as follows: _ Brown _ From the vertebrate and invertebrate remains it seems very clear that these rocks are not of Fort Union age, but as shown by the plants the climatic conditions of Fort Union time were long foreshadowed toward the close of the Cretaceous. The dinosaur-bearing beds beneath the Puerco formation of northern New Mexico were briefly described under the name Ojo Alamo beds. The final conclusion of the paper was as follows: There is no doubt that the Hell Creek beds were synchronous with the Lance, and little doubt that the Belly River and Ojo Alamo beds should be correlated with the Judith River. The Edmonton is intermediate in age between the Judith River and the Lance. W.D. Matthew” stated that the term “ Paleo- cene” as he used it ‘denotes what we have been calling basal Eocene, comprising the Fort Union, Puerco and Torrejon, and other equivalent formations older than Wasatch or typical lower Eocene.” Matthew gave lists of the vertebrate faunas of the Puerco, Torrejon, Paskapoo, and Fort Union and made comparisons between them and those of the Lance and Belly River and with the Wasatch. In an interpretation of the faunas he stated: “The evidence of fossil vertebrates in correla- tion is very valuable, provided it is interpreted correctly.” The difference between two faunas may be due, he said, to “lapse of time; differ- ence of local environment; migration move- ments representing a change in environment somewhere else, not necessarily in the region concerned.”’ With these precautions in mind Matthew presented the table reproduced in figure 1. 29 Evidence of the Paleocene vertebrate faura on the Cretaceous- Tertiary problem: Geol. Soc. America Bull., vol. 25, pp. 381-402, 1914, “clearly of - LARAMIE FLORA OF THE DENVER BASIN.. The correlation of the faunas here involved with the European succession is of special interest. It was shown that the Thanetian (Cernaysian) has furnished a ‘small fauna of mammals and reptiles, comparable in facies to our Torrejon and apparently of equal age.” The Sparnacian and Ypresian, which include the London clay, the Argiles plastique . of the Paris Basin, and equivalents in Belgium and elsewhere, are equivalent to our Wasatch. According to Matthew, the Puerco, arbitrarily correlated by Osborn with thé Montian, ‘‘has no certain equivalent in Europe,” and he stated that the “Lance is equally difficult to correlate,’’ as “there are no European forma- tions of corresponding facies in the late Cretaceous.” As regards faunal migrations anit diastro- phism the following statements were made: As I read the evidence from the vertebrates it is to this effect: 1. From the Belly River to the Lance there is a con- siderable lapse in time, but they represent the same faunal facies and they indicate that there was no great migration movement intervening, and hence no great upheaval, either continental or universal. There was un- doubtedly a considerable local uplift along the Rocky Mountain ridges and extensive recession of the sea from the plains to eastward of them. 2. Between the Lance and the Paleocene there is a some- what smaller lapse in time but a very marked change in fauna; but they do not represent the same facies, and while a great migration movement is probably indicated by the extinction of the dinosaur phyla and incoming of certain groups of placental mammals (Creodonta, Con- dylarthra, etc.), its extent remains a little uncertain. 3. Between the Paleocene and Eocene a great migration movement intervenes, the progressive orders of placental mammals, of turtles, and perhaps other groups appearing simultaneously in Europe and North America. The lapse of time between the uppermost Paleocene and lowest Eocene is slight. If, therefore, we are to use diastrophic criteria as the basis of our geologic classification, the dividing line be- tween Cretaceous and Tertiary should be drawn either between the Lance and the ‘Paleocene or between the Paleocene and Eocene. It should not be drawn between Belly River and Lance. The following is Matthew’s conclusion: The question to my mind shapes itself thus: Does the evidence conclusively support the present classification; and, if not, is it sufficiently conclusive to warrant our changingit? Ihave indicated what I regard as the weight and trend of the vertebrate evidence. Without entering into any detailed criticism of the stratigraphic and paleo- botanic evidence, a task for which others are far more com- petent, I may say that to me it appears to be inconclusive because it does not allow for the characteristics of epicon- HISTORICAL REVIEW OF tinental formations nor for the varying facies of faunas and floras; that the asserted maghitude of the break be- tween Laramie and Lance rests not on evidence but on a definition of the Laramie; and that no really adequate evi- dence has been adduced of its relations to the Cretaceous- Tertiary break in Europe. The paleobotanic argument for placing the Lance in the Tertiary is the resemblance. 7 THE LARAMIE PROBLEM. 89 their absence from the Laramie is obviously due to a differ- ence in environmental conditions. The facies of the fauna is different, and much,,if not all, of the difference in flora should be ascribed to this cause. For these and many: other reasons the evidence in favor of transferring the Lance and associated formations to the Tertiary appears to me inconclusive and is directly in WYOMING WESTERN EUROPE NEW MEXICO eevee. I eee presian | q Wasatch |-------—--------------------- > Wasatch a ] : ? _Sparnacian & af MONTANA ly > h i Thanetian © Torrejon ] Fort Union For Union: ||P rt te eee ~ / i ast th obs, ALBERTA 7 e Puerco f Lance Hell Creek Paskapoo Danian / ene eee i : ei Y \ . . 5 Ojo Alamo ‘ Fox Hills Fox Hills Edmonton \ are beg ° ‘ : a) Q \ Pierre Pierre Upper G an) Senonian Serr, poCe to po ween a] pee < ‘. Pierre | Judith River* Belly River , ane Le K Pierre Pierre s on i _ & es ; na Lower © *Straugraptic position disputed Senonian FiGuRE 1.—Approximate correlations of typical formations of late Cretaceous and early Tertiary in Europe and western America, based on their vertebrate faunas. After W.D. Matthew, Geol. Soc. America Bull., vol. 25, p. 393, 1914. of its flora to that of the Paleocene and its great difference from that of the true Laramie. But there is no evidence that the Lance flora was absent from Europe in the late Cretaceous, and the Laramie clearly represents a different facies from the Lance. Dr. Knowlton hasinsisted strongly on the entire absence of dinosaurs in the true Laramie, apparently with the idea that it showed it to be much older than the Lance. But as the same phyla of dinosaurs are, conflict with the evidence from fossil vertebrates, so far as I am able to understand it. The final paper of the symposium was pre- sented by W. J. Sinclair * and later published under joint authoriship with Walter Granger. 30 Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San Juan Basin, N. Mex.: Am. Mus. Nat. Hist. Bull., vol. 33, pp. 297-316; present in the older Belly River and in the newer Lance, | 914. x 40 As the title indicates, the authors were con- cerned principally with the lower Eocene mam- mal-bearing formations and only incidentally with the underlying dinosaur-bearing- beds. As this phase of the paper is treated at length under the discussion of the San Juan Basin (pp. 69-76) it need not be further considered here.. In May, 1914, after a prolonged discussion of all the lines of evidence then available, it was decided by the United States Geological Survey that, so far at least as its official publi- cations are concerned, the Lance formation is to be classed as “Tertiary (2)” instead of ‘Cretaceous or Tertiary,” as previously, and that the Arapahoe, Denver, Dawson arkose, and Raton formations, with which I believe the Lance formation to be in part synchronous, are to be classed as Eocene instead of Cretaceous. One of the first places in which this newer interpretation of the position of the Lance formation appears was a paper by Bauer,” published in 1914. This paper presented the results of an examination of an area in north- eastern Montana along the north border of the Fort Peck Indian Reservation. The only sedimentary formations present are the Lance _ and Fort Union. Concerning the line between them Bauer said: ' Owing to the absence of a sharp lithologic boundary | ‘between the formations and to the lack of exposures near the critical horizon in this field and also in the northern part of the reservation, the accurate mapping of the Lance- Fort Union boundary is impossible. In drawing the line shown on the map the known outcrops of somber-colored beds are considered to belong to the Lance, and those of yellow beds to the Fort Union. * * * Its [the Lance’s] separation from the overlying Fort Union forma- tion is thus based on its stratigraphic position and litho- logic character. In these particulars it agrees with the Lance formation as recognized in other areas in eastern Montana and in North Dakota, where it is further charac- terized by a dinosaur fauna which has not been found in the Fort Union. Formerly the Survey considered the evidence of the age of the Lance so conflicting that it was ascribed to the Cretaceous or Tertiary, but recently the close correlation of the Lance flora with that of well- determined Tertiary formations of the Gulf coast, con- sidered together with the mountain-making movements that are supposed to have immediately preceded the de- position of the strata, has led the Survey to assign the formation to the Tertiary (?) system. A small coal area on the west side of Big Horn River, Mont., in the angle formed by its 41 Bauer, C. M., Lignite in the vicinity of Plentywood and Scobey, Sheridan County, Mont.: U. S. Geol. Survey Bull. 54l, pp. 293, 315, 1914. -considerable LARAMIE FLORA OF THE DENVER BASIN. junction with the Yellowstone, was described by Rogers.? The strata examined are mainly referable to the Lance formation, concerning which Rogers said: The Lance formation in this area may be divided into two parts, namely, a coal-bearing member, which com- prises the upper 250 feet, and a lower portion about 900 feet thick. This distinction is made partly on lithologic grounds and partly because of the slight difference in the fossils found in the two divisions. In the same volume with the two papers just mentioned was one by Lloyd*® on the lignite field of the Cannonball River region, N. Dak. The four principal sedimentary for- mations recognized were the Fox Hills sand- stone, Lance, Fort’ Union, and White River (Oligocene). Concerning the Fort Union and Lance formations he said: The Fort Union formation, of the lower part of the Tertiary system (Eocene), which contains the greater part of the valuable lignite in the Dakotas and eastern Mon- tana, embraces the surface rocks in the western and northwestern parts of the Cannonball River field. Under- neath the Fort Union is a series of beds which are now tentatively classified as probably of early Tertiary age and which have been referred to the Lance formation. The upper 250 or 300 feet of this formation is in the field markedly different in lithologic character from the under- lying more typical Lance and has been found at numerous places to contain the remains of a marine fauna which has not previously been known in this part of the strati- graphic section. These beds have been mapped separ- ately and are herein designated the Cannonball marine member of the Lance formation. The underlying lower part of the Lance is of fresh-water origin and is composed of alternating beds of shale and sandstone which on erosion give rise to the badlands described above. Its thickness is approximately 400 feet. The fauna of the Cannonball member was alluded to as follows: ‘‘In the Cannonball River field several collections of marine in- vertebrate fossils made from the Cannonball member * * * have been identified by T. W. Stanton as belonging to a modified Fox Hills fauna.”’ In 1915 Lloyd and Hares** described in detail the areal distribution, lithologic character, and stratigraphic relations 32 Rogers, G. S., Geology and coal resources of the area southwest of Custer, Yellowstone and Big Horn counties, Mont.: U. S..Geol. Survey Bull. 541, pp. 316-328, 1914. % Lloyd, E. R., The Cannonball River lignite field, Morton, Adams, and Hettinger counties: N. Dak.: U.S. Geol. Survey Bull. 541, pp. 243- 292, 1914. ; 34 Lloyd, E. R., and Hares, C. J., The Cannonball marine member of the Lance formation of North and South Dakota and its bearing cn the Lance-Laramie problem: Jour, Geology, vol. 23, pp. 623-547, 1915. HISTORICAL REVIEW OF of the Cannonball member and argued for its probable Cretaceous age. They wrote: Field examinations by the writers and the paleonto- logical determinations by Drs. Stanton and Knowlton during the years 1912 and 1913 show that in a large area west of Missouri River in North and South Dakota the Lance formation consists of two distinct parts—a lower nonmarine part containing a flora very similar to if not identical with that of the Fort Union, and an upper marine member containing a fauna closely resembling but not identical with that of the Fox Hills sandstone. This upper part, on account of its peculiar fauna, has been mapped separately and named the Cannonball marine member of the Lance formation. Farther west nonmarine beds bearing lignite and occupying a similar stratigraphic position have been named the Ludlow lignitic member of the Lance. After describing the areal distribution and giving a number of sections of the strata, they proceeded to a discussion of interrelationships. The fauna of the Cannonball was studied by T. W. Stanton, who wrote concerning it as follows: The fauna of the Cannonball member of the Lance may now be characterized as a modified Fox Hills fauna, It contains a considerable proportion of undescribed species of Cretaceous affinities, and it is noteworthy that a number of the most common Fox Hills species have not been dis- covered in this fauna. * * * In this list of about 40 forms there are 21 named species and varieties, of which 15 occur in the Fox Hills, 4 occur in the Pierre, and 5 were originally described from rocks now known to belong to the marine member of the Lance. One species, Cor- bicula cytheriformis, was described from the Judith River formation and is known in the Mesaverde formation and the Lance of other areas. After presenting and weighing the several lines of evidence that. may be used in fixing the age of the Cannonball, these authors con- cluded as follows: A recent detailed consideration of all the evidence has led to a decision by the United States Geological Survey that the Denver and Arapahoe, Dawson, and Raton forma- tions in Colorado and New Mexico all be placed in the Tertiary system. This decision was based primarily on the correlation of these formations with the Wilcox forma- tion of the Gulf region on the evidence of their fossil floras and also on the consequent correlation of the unconformi- ties in the two regions. Although the Lance formation is believed to be of the same age as the Denver, Raton, and “Upper Laramie,” it is classified by the United States Geological Survey as Tertiary (?), the doubt being thus expressed on account of the Cretaceous character of the Cannonball marine fauna. The writers believe that greater weight: should be given to the evidence of the marine faunas and the dinosaurs, and that, in view of the strong evidence presented by these faunas, the correla- tions made on the basis of fossil floras should not be. considered as conclusive. THE LARAMIE PROBLEM. 41 In a final footnote they added that ‘‘further studies on the Lance problem have strength- ened the conviction of the writers that the Lance is Cretaceous.” FORT UNION FORMATION. The early history of the Fort Union forma- tion, or‘‘Great Lignitic,”’ as it was at first called, has been sufficiently set forth in the preceding pages. In fact, it was not until the Laramie was established that the element of discord was introduced which gave rise to so much subse- quent discussion and difference of opinion. Most of the geologists and paleontologists who had studied the Fort Union contended for its Tertiary age, and Newberry, who investigated the flora, was at first inclined to refer it to the Miocene. It appears that Hayden was in the end more or less responsible for promulgating what has since been accepted as an erroneous view regarding the relation of the Fort Union to the Laramie. When the Laramie was adopted by Hayden, he made it include or at least be equivalent to the Fort Union, as the following statement shows:** If objection i is made to the use of the term ‘‘Lignitic” group, I would say that in this work it is restricted to a series of coal-bearing strata lying above the Fox Hills group, or Upper Cretaceous, and these are embraced in the divisions Laramie and Fort Union. On the same page Hayden continued: As far back as 1859 it was my belief, founded on what appeared sufficient evidence, that the sequence between the well-characterized Cretaceous strata and those of the Lignite group, as defined at that time, was continuous, and that the chasm that was supposed to exist between the Cretaceous and the Tertiary epoch would be found to be bridged over. He then proceeeded to quote Dr. C. A. White, who, he said, had made a critical examination of these formations during the past season, and he says that his investigations have freely confirmed the views expressed by me some years ago and indicated by the paleontological studies of Mr. Meek, that the Fort Union beds of the upper Missouri River are the equivalent of the Lignitic formation as it exists along the base of the Rocky Mountains in Colorado. Inasmuch as the Fort Union was regarded as equivalent to the lignite-bearing beds east of the mountains in Colorado, which fell within the typical areas included by King in the Laramie, it of course followed that the 8 Hayden, F. V., letter of transmittal for Lesquereux’s “Tertiary flora”: U. S. Geol. Survey Terr. Rept., vol. 7, p. iv, 1878. 42 Fort Union was regarded by Hayden as of the same age as the Laramie, if not, indeed, in- cluded in it. As is well known, Hayden originally consid- ered all of his Paranee (Laramie and Fort Union) as of Tertiary age, but his latest con- clusion was that the whole mass was of a transi- tional character—that is, it formed beds of pas- sage between the Cretaceous and Tertiary. Newberry * in commenting on this conclusion said: ‘‘It is easy to see that this result was inevitable, after he had united an Upper Cre- Waceous with a Tertiary formation under one name.’ Clarence King, however, did not accept Hayden’s reference of the Fort Union to the Laramie. When preparing the final volume on the systematic geology of the vicinity of the fortieth parallel, he had before him Lesquereux’s ‘Tertiary flora,’’ above quoted, and after admitting that he had never visited the locality and could not therefore ‘speak with any definiteness,”’ he added (p. 353): I consider it worth while to point out here a noticeable ambiguity in its evidence. Cope, in his introduction to his volume on the Cretaceous, cites dinosaurs as coming from the Fort Union, from which he refers the fauna to the Mesozoic series, istic plant life of the country differs entirely from that described by Lesquereux in Volume II, Tertiary flora. It is noticeable that he nowhere describes in that volume any of the plants from the classic Fort Union locality, a series which has been studied by Newberry and which coatains not only a general resemblance but some actual species identical with the Miocene of Greenland and northern Europe. * * * Until fresh evidences of the stratigraphical relations, and a full discussion of the fauna of the whole series of rocks at Fort Union is fully ‘made, a definite correlation is impossible, and at present writing the entire difference between the plants at Fort Union and anything in Colorado or Wyoming that is of value at all suggests that they can not be related to any of the southern groups. I apprehend that the plant horizon at Fort Union will be found to be nothing but a northward extension of the White River Miocene. King’s reference of the Fort Union to the White River has not of course been sustained, but otherwise his suggestions have proved to be wonderfully near the truth. C. A. White did much to merge the Fort ‘Union in the Laramie. In fact, in what was 38 Newberry, J. S., The Laramie group: New York Acad. Sci. Trans., vol. 9, p. 3, 1889 (reprint). formation. On the other hand, the character-. LARAMIE FLORA OF THE DENVER BASIN, perhaps his last utterance *’ on the subject he said: The localities at which Laramie strata were first studied by geologists were often distant from one another, and they were not then recognized as constituting one great * * * These deposits consequently re- ceived a different name in each district. They thus have received such names as Fort Union group, Judith River group, Lignitic group, and Bitter Creek series. The term Lignitic soon came to be applied to the strata of several districts which are now included in the Laramie. It was not possible, according to White, to distinguish between Fort Union and Laramie by the invertebrates, and this view was generally entertained by paleontologists for many years thereafter. The influence of what are now known to have been the erroneous views of Hayden, White, and others is well shown in Ward’s elaborate paper “Synopsis of the flora of the Laramie group,” * in which he included in the Laramie not only the Fort Union but also beds now known to belong to the Montana, Arapahoe, Denver, Lance, and other formations. It should not be presumed, however, that he failed to note that there were striking differences be- tween the typical Laramie flora and that of the Fort Union, but he was misled by the opinion of the time that all the formations he included - formed an unbroken sedimentary’ sequence. His investigation was undertaken primarily to ascertain the bearing of the plants on the ques- tion of the age of the Laramie, but naturally it failed in reaching definite results. In this pa- per Ward described many new forms from a great many localities and horizons, though so many were from the Fort Union that New- berry, in commenting on it, said: ‘But his monograph as a whole is simply an important contribution to what was before known of the Fort Union flora.” Itis undoubtedly to J.S. Newberry that most credit is due for keeping alive and insisting upon the distinctness of the Fort Union from the Laramie. From the beginning of his studies of the material collected by Hayden in 37 White, C. A., Correlation papers—Cretaceous: U. S. Geol. Survey Bull. 82, p. 147, 1891. 38 Ward, L. F., U. S. Geol. Survey Sixth Ann. Rept., pp. 399-557, pls. 31-65, 1886, 89 Newberry, J. S., The Laramie group: New York Acad. Sci. Trans., vol. 9, p. 4, 1889 (reprint). HISTORICAL REVIEW OF THE LARAMIE PROBLEM. 2 the fifties until his death he maintained its Tertiary age. In the paper above quoted he said: Whether the Laramie is Cretaceous and the Fort Union Tertiary are other questions, but they are certainly distinct from each other—distinct in the general botanical facies of their floras as well as in the absence of common species, That the Fort Union is Tertiary there can be no reasonable doubt; it has many species in common with the recognized ‘Tertiary in the Canadian provinces of North America, in Greenland, and in the British islands, and it contains some plants which are living at the present day, such as Onoclea sensibilis, Taxodium distichum, Corylus americana, C. rostrata, etc. Moreover, the grouping of the plants com- posing it gives it a facies which enables one to recognize it at a glance. The abundance of species and specimens of Populus, Viburnum, and Corylus imparts to it an aspect as different from that of the flora of the Laramie as are the recent floras of Europe and America from each other. In his last published utterance on this subject Newberry “ made the following emphatic statement: The floras of the Laramie and Fort Union groups are totally distinct, and these formations should be referred to different geological systems—the Fort Union to the Ter- , tiary and the Laramie to the Cretaceous. In 1896 W. H. Weed * published a short paper entitled ‘‘The Fort Union formation,” in which, after briefly reviewing the early his- tory of the Fort Union and Newberry’s con- tention that it should be referred to the Ter- tiary, he described the geologic section in the vicinity of the Crazy Mountains, in Montana, where, he said, the Fox Hills, Laramie, Living- ston, and Fort Union formations are super- imposed. This view I hold to be in the main correct, although, as will be shown later in the discussion of the Livingston formation, there are many who do not accept it. In any event, it was made plain that the Fort Union forma- tion of this region was above beds that should properly be referred to the Laramie or were in its position. More than. 25 years ago I became convinced of the correctness of Newberry’s conclusion as to the Tertiary age of the Fort Union formation, and in many papers and reports published since that time I have consistently adhered to this view. It is perhaps not necessary further to allude to these papers, nor is it possible to fix an exact date on which the Fort, Union became generally accepted as a Tertiary unit. 40 Newberry, J. S., The Laramie group: Geol. Soc. America Bull., vol. 1, p. 525, 1890. 1 Am, Geologist, vol. 12, pp. 201-211, 1896. 43 The term with the present accepted applica- tion has been in current use for a dozen years or more and apparently is no longer seriously questioned. As an example of the completeness of this change mention may be made of the treatment -of the Fort Union in the reports of the Geologi- cal Survey of North Dakota. Thus, in the third biennial report of the State geologist, published in 1904, the term Fort Union does not occur, all beds under consideration being referred to the Laramie, but in the fifth biennial report, issued in 1908, the conditions were reversed and the Laramie was no longer accepted as present, all the beds being referred to the Fort Union or Lance. In a geologic map of North Dakota, published by A. G. Leonard ” in 1913, the Laramie was not recog- nized, but nearly half of the State was shown to be covered by the Fort Union formation. In the text accompanying this map Leonard said: The Fort Union is one of the best-known formations of the Northwest. It covers a vast area east of the Rocky Mountains, stretching from Wyoming to the Arctic Ocean in the valley of the Mackenzie River and including part of several Canadian provinces, much of western North Dakota, eastern Montana, northwestern South Dakota, and central and eastern Wyoming. 7 “LARAMIE” IN THE CANADIAN PROVINCES. It appears that as early as 1873 George M. Dawson, while acting as geologist to the British North American Boundary Commission, noted the presence at certain points along the inter- national boundary of lignite-bearing beds that he identified with the ‘‘Great Lignitic or Fort Union group” of Hayden, as exposed along Missouri River. This view was affirmed the following year in an article on the ‘‘Lignite formations of the West,” “ in which this state- ment was made: In view of the evidence of the preponderant animal and vegetable forms, it seems reasonable to take the well-marked base of the Lignite series as'that of the lowest Tertiary, at least at present. The formations described belong to this lowest Tertiary, being in fact an extension of Hayden’s Fort Union group, and from analogy may be called Eocene. So far as I have been able to ascertain, the term Laramie was first applied in the Canadian provinces also by Dawson “ in his ‘‘Report on “2 The geological map of North Dakota: North Dakota Univ. Quart. Jour., vol. 4, No. 1, October, 1913. - : 48 Dawson, G. M., Canadian Naturalist, new ser., vol. 7, p. 252, 1874. 4 Dawson, G. M., Canada Geol. Survey Rept. Progress for 1879-80, pp. 127-134B. 44 an exploration from Fort Simpson, on the Pacific coast, to Edmonton, on the Saskatche- wan, embracing the northern part of British Columbia and the Peace River country.” In discussing the Peace River section he several times alluded to the Laramie as following the Fox Hills conformably, but whether he in- tended to refer it to the Cretaceous or the Tertiary is not quite clear, though in a ‘‘com- parative table of Cretaceous rocks’ he made the so-called Laramie equivalent to the Fort Union and Judith River beds of Nebraska and Missouri rivers and also to the ‘‘Lignite Tertiary” of the forty-ninth parallel. A year or two later, in his preliminary paper on the ‘‘Geology of the Bow and Belly River region,”’ Dawson * took occasion to. define the use of Laramie as follows: The term Laramie is used in a general sense for the Upper Cretaceous or lower Eocene beds which overlie the Fox Hills series (Cretaceous No. 4). It is not intended by its use to differentiate the beds so named from those of the Judith River and Fort Union series, with which they may be found to blend as the intervening district is more com- pletely explored. In describing the general arrangement of the beds in the Belly River region, Dawson gave the following section: Beds of the Porcupine Hills, chiefly thick- bedded sandstones and, some shales. He Willow Creek series. Reddish and purplish clays with gray and yellow sandstones. Laramie. St. Mary River series. Sandstones, shales, and clays of general grayish or grayish - green colors. Yellowish sandstones and shaly beds, with a mingling of fresh-water and brackish or marine mollusks. Fox Hills. regular in thickness and character. Mol- lusks all marine. | Pierre. Blackish and lead-colored shales, etc. Niobrara (?).| Belly River series. The complete report on the “country in the vicinity of Bow and Belly rivers, North- 45 Dawson, G. M., Canada Geol. Survey Rept. Progress for 1880-1882, p. 2B, 1883. Yellowish sandstones, with some shales, ir- | LARAMIE FLORA OF THE DENVER BASIN. west Territory,” was published by Dawson * in 1885. In this report the descriptions of the “Laramie” are amplified and the thick- ness given. Thus the Porcupine Hills beds are given a thickness of 2,500 feet, the Willow Creek beds 450 feet, end the St. Mary River beds 2,800 feet. Dawson “ continued his explorations in the Canadian Rocky Mountains, his report pub- lished in 1886 including that portion from the international boundary northward to the head- waters of Red Deer River. In this report he alluded many times to the presence of the “Laramie” but always with the signification already given to it. In the same volume R. G. McConnell * pub- lished a “Report on the Cypress Hills, Wood Mountain, and adjacent’country in Assiniboia,”’ in which he referred to the current uncertainty regarding the position of the “Laramie” and adopted the view that it is probably transi- tional between Cretaceous and Tertiary. In the Cypress Hills and vicinity, according to McConnell, it is apparently conformable to the Fox Hills sandstone and of small thickness, but in the Wood Mountain region it was found to be better represented and in some places capable of being divided into three ‘somewhat dissimilar groups.” He quoted extensively from Dawson’s report of 1875. In the following year (1887) J. B: Tyrrell Bi presented an important paper on northern Alberta and adjacent districts in Assiniboia and Saskatchewan, in which he made a:com- plete realinement of the “Laramie,” although still using it as a group term. He established the Edmonton and Paskapoo series in substitu- tion for the names proposed by Dawson. As these terms have now come into wide usage the formations may be described at some length. The Edmonton series, which comprises the lower 700 or 800 feet of Dawson’s St. Mary River series, was described as follows: This is perhaps, on the whole, the most characteristic series of the entire region, for though its.thickness, wher- ever determinable, was never found to exceed 700 feet, the horizontal position of the strata causes it to underlie a very large extent of country. 4¢ Dawson, G. M., Canada Geol. Survey Rept. Progress for 1882-1884, pp. 1-159c, 1885. ' Dawson, G. M., Canada Geol. and Nat. Hist. Survey Ann. Rept., new ser., vol. 1, for ‘885, pp. 1-169B, 1886. 48 Idem, pp. 1-85c. i ‘© Canada Geol. and Nat. Hist. Survey Ann. Rept., new ser., vol. 2, for 1886, pp. 1-176E, 1887. HISTORICAL REVIEW OF It consists generally of whitish or light-gray clay and soft clayey sandstone, weathering very rapidly, with more or less rounded outlines. In some places, as on Red Deer River and in the Hand Hills, it is seamed with a great number of beds of ironstone, which with thin beds of lig- nite and lignitic shale give a definite banded character to all the escarpments. It also contains a great number of nodules of compact ironstone, which are often perched on little pinnacles cut out of the soft sandstone. In the north- ern portion, especially along the North Saskatchewan, the banded appearance is seldom seen, though with the ex- ception of a smaller quantity of ironstone, the rock has very much the same character as further south. This is essentially the coal-bearing horizon within the district, all the coal found east of the foothills, except probably the seams on the upper North Saskatchewan and at Egg Creek, being of thisage. The top of the formation is marked by an extensive coal deposit seen first in the Wintering Hills as a thin bed of carbonaceous shale, but on being traced northward is found to thicken very greatly, till on the North Saskatchewan, near Goose Encampment, it has a thickness of 25 feet. The bottom of the series lies conformably on the Pierre shales, without any sharp line of demarcation between the two. In fact, the shales gradually lose their massive character and change almost insensibly into thin beds, which are of decidedly brackish- water origin. In the Pierre remains of land plants and animals are very rare, while here traces of land plants become fairly plentiful, and on Red Deer River dino- saurian bones are met with in great abundance, showing, with the presence of estuarine shells, the partly land- locked character of the area within which the beds were deposited. Toward the west’ the Edmonton gradually disappears beneath the overlying beds of the Paskapoo, and, Tyrrell added, | In many places the junction of the Pierre and Laramie was plainly seen, the sandstones of the Paskapoo series appearing to rest conformably on the shales of the Pierre, so that the Edmonton series seems to thin out and disap- pear between its western outcrop and the eastern edge of the foothills. The Edmonton was identified with the lower division of the Laramie in the Cypress Hills region, described by McConnell, and with the Wapiti River group of Dawson in the Peace River region. The Paskapoo series was said to include “all the Laramie rocks lying above those of the Edmonton series’? and to embrace Dawson’s “Porcupine Hills and Willow Creek series and all but the lowest 700-900 feet of his St. Mary River:series.”’ The maximum thickness noted was 5,700 feet. The beds, according to Tyrrell, consist of more or less hard light-gray or yellowish, brown- ish-weathering sandstone, usually thick bedded but often showing false bedding; also of light bluish-gray and olive 85344—22—4 THE LARAMIE PROBLEM, 45 sandy shales often interstratified with bands of hard lamellar ferruginous sandstone and sometimes with bands of concretionary blue limestone, which burns into excel- lent lime. * * * The whole series, as shown by its invertebrate fauna, is of fresh-water origin. The lists of fossils given by Tyrrell show clearly that the Paskapoo is to be correlated with the Fort yee of the Missouri River region. ‘As regards the age of the ‘‘Laramie,” Tyrrell concluded, after briefly reviewing the evidence, that it seems reasonable to place the close of the Cretaceous epoch at the time of the deposition of the topmost beds of the Edmonton series, and that the Tertiary epoch began with the commencement of the Paskapoo period, during which a great thickness of sandstones and sandy | shales was laid down without any apparent break or un- conformity. In the same volume as that containing Tyrrell’s report George M. Dawson * presented certain ‘‘Notes to accompany a geological map of the northern portion of the Dominion of Canada, east of the Rocky Mountains,” in which he stated that in thé valley of Mackenzie River near the mouth of Bear Lake River Richardson found rocks which he referred to the ‘‘Lignite formation” but which ‘‘with little doubt represent the series now known as the Laramie.” In the subsequent annual reports of the Canada Geological Survey the ‘‘Laramie”’ continued to receive occasional mention, but ° no extensive papers in which it was involved were published, and the usage of the term con- tinued about as established by Tyrrell for central Alberta. A number of papers. were published from time to time by Sir William Dawson, J. F. Whiteaves, E. D. Cope, L. M. Lambe, and others on different phases of the paleontology of the Canadian ‘‘Laramie.”’ Thus, as early as 1885 Whiteaves.* published a ‘‘Report on the Invertebrata of the Laramie and Cretaceous rocks of the vicinity of the Bow and Belly rivers and adjacent localities in the Northwest Territory,” in which he de- scribed some 35 species from the so-called Laramie of Alberta and the Souris River dis- trict, this being a paleontologic supplement to Dawson’s paper on the same region already noted. He also described many species from the Belly River series, of which he said: 50 Canada Geol. and Nat. Hist. Survey Ann. Rept., new ser., vol. 2, for 1886, pp. 18, 19R, 1887. 51 Whiteaves, J. F, Contr. Canadian Paleontology, vol. 1, pt. 1, 1885, 46 Judging from their respective invertebrate faunae, it would seem impracticable to separate the ‘‘Belly River series” from the Laramie and more especially from the “Judith River group” on purely paleontological evidence. Dawson published several papers on the flora of the ‘‘Laramie.” In a paper on the Cretaceous and Tertiary floras of British Columbia and the Northwest Territory ® he gave lists of ‘‘Laramie” plants from several localities. He considered the so-called Laramie as equivalent to the Fort Union, and the plants mentioned undoubtedly bear: this out. In 1885, in his paper on the Mesozoic floras of the Rocky Mountain region of Canada,® he dis- cussed the Belly River and so-called Laramie series, which he then failed to differentiate. He divided the ‘‘Laramie” into three ‘‘groups”— the ‘‘Lower Laramie,’’ which embraced the St. Mary River series of George M. Dawson; the ‘‘Middle Laramie,” or Willow Creek series of Dawson; and the ‘‘Upper Laramie,” or Porcupine Hill series of Dawson. To judge from the lists of plants given, it would seem that there had been some mixture of horizons when the collections were made. Dawson’s third paper, on the fossil plants of the Laramie formation of Canada,* introduced still another set of terms. He stated that the ‘‘Laramie” of Canada occurs in two large areas west of the 100th meridian and separated from each other by a tract of older Cretaceous rocks. The eastern of these areas extends for some distance along the United States bound- ary between the 102d and 109th meridians and northward nearly to the parallel of 51°. Here, he said, the lowest beds of the ‘‘Laramie’”’ rest on Fox Hills and are overlain by Miocene. He continued: . : They are undoubtedly continuous with the Fort Union group of the United States geologists on the other side of the international boundary, and they contain similar fossil plants. They are divisible into two groups—a lower, mostly argillaceous, and to which the name of ‘Bad Lands beds,’’ may be given from the ‘‘badlands” of Wood Mountain, where they are well exposed, and an upper, partly arenaceous member, which may be named the Souris River or Porcupine Creek division. In the lower division are found reptilian remains of Upper Cretaceous type, with some fish remains more nearly akin to those of the Eocene. The western area is of still larger dimensions and extends along the eastern base of the Rocky 52 Roy. Soc. Canada Trans., vol. 1, sec. 4, pp. 15-34, AER 58 Idem, vol. 3, sec. 4, pp. 1-22, 1885. 4 Idem, vol. 4, sec. 4, pp. 19-34, 1887. | eastward to the 111th meridian. LARAMIE FLORA OF THE DENVER BASIN. Mountains from the United States boundary to about the 58th parallel of latitude and thence In this area three divisions of the beds are made: (1) The Lower Laramie, or St. Mary River series, corresponding in its character and fossils to the Lower or Bad Lands division of the other area; (2) a middle divi- sion, the Willow Creek beds, not recognized in the other area; (3) the Upper Laramie or Porcupine Hills division, corresponding in fossils and to some extent in mineral character to the Souris River beds of the eastern area. The paper enumerated 51 forms of plants, of which 10-were found in the ‘‘ Lower Laramie”’ and the remainder in the ‘‘Upper Laramie,”’ with about 8 in common. It is essentially a Fort Union flora. Several years later Dawson® published another short paper dealing mainly with plants from Mackenzie River, which he showed are to be identified with the Fort Union. In 1893 Whiteaves * delivered a presidential address before the Royal Society of Canada, on ‘‘The Cretaceous system of Canada,” which was mainly an enumeration of the fossil forms that had been recorded from the several members of the Cretaceous. Although he did not specifically so state, it is evident that he included in the ‘‘Laramie’”’ both the ‘‘Lower Laramie” and “Upper Laramie’”’ of previous writers, and of gourse it was all regarded as Cretaceous. In 1908 D. P. Penhallow * presented an elaborate «Report on Tertiary plants of British Columbia,”’ which was based primarily on collections made by L. M. Lambe in 1906 but which was made to include all previous work by Dawson and others within this area. If Penhallow had’ taken occasion to revise the earlier work, this could have been made a very valuable contribution, but unfortunately he made no attempt at revision and the lists were compiled without change. The ‘Laramie’’ here was said to include only the ‘‘Upper Laramie” (Paskapoo of Tyrrell), which was made synonymous with Fort Union, lower Eocene, and ‘‘Lignite Tertiary.” The conclu- sion of Sir William Dawson that the ‘‘Upper Laramie” is undoubtedly of Tertiary age was confirmed. 55 Dawson, William, On fossil plants from the Mackenzie and Bow rivers: Roy. Soc. Canada Trans., vol. 7, sec. 4, pp. 69-74, 1889, 58 Whiteaves, J. F. » Roy. Soc. Sanaa Trans., vol. 9, sec. 4, pp. 1-19, 1893. 57 Canada Geol. Survey Mem. 1013, pp. 1-167; 1908. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. For a decade or more after the publication of the papers above mentioned very little investigation appears to have been prosecuted in the areas covered by the so-called ‘‘ Laramie,” and the subject remained practically as left by the earlier writers. Then, in a valuable paper published in 1909, by D. B. Dowling,® on the ‘‘Coal fields of Manitoba, Saskatchewan, Alberta, and eastern British Columbia,’’ the “Laramie” was said to embrace the Edmonton and Paskapoo with the significance attached by Tyrrell, from whom extensive quotations were taken. Dowling’s report was summarized in the report of the Director of the Canadian Geologi- cal Survey,*® who gave a full-page table of correlations of the formations involved, in which the “Laramie” was assigned the in- terpretation adopted by Dowling. In the following year Dowling © published a short bulletin on the Edmonton coal field, Alberta, which was devoted mainly to -the wonderfully rich coal deposits of the Edmonton formation. The term “Laramie”’ mentioned in this bulletin, but the Edmonton was ‘classed with the undoubted Cretaceous beds below and represents the upper member of this geries.”’ The plants listed, if correctly identified, indicate a mixture of Cretaceous and Tertiary (Fort Union)- types. In 1913 Malcolm" published a paper on the “Oil and gas prospects of the Northwest Provinces of Canada,” in which the Edmonton and Paskapoo were grouped under the ‘ Lara- mie” with the following qualification: In placing under this heading the formations to be described, it is not the intention of the author to indicate in this way the precise age of the formations or to indicate the dividing line between the great geological systems. The grouping is for convenience in description and for the purpose of showing the stratigraphic relations of the formations. There seems, however, to have been no general understanding or usage, and in the Summary Report of the Canada Survey for 1913, published in 1914, D. B. Dowling ®' had a short paper on the Sheep River gas and oil field of Alberta, in which the Paskapoo was put into the Tertiary and the Edmonton into 88 Canada Geol. Survey Pub. 1035, pp. 38-43, 1909. 59 Canada Geol. Survey Summary Rept. for 1909, p. 38, 1910. 6 Dowling, D. B., Canada Geol. Survey Mem. 8E (Pub. 1115), 1910. 6 Malcolm, Wyatt, Canada Geol. Survey Mem. 29E, 1913. 8 Canada Geol. Survey Summary Rept. for 1913, p. 142, 1914. was not. 47 the Cretaceous, but the term “Laramie” was riot used. In the same volume Bruce Rose ® had a short paper on the Willowbunch coal area, Saskat- chewan, in which he stated that the only rocks exposed in this area are to be referred to the Fort Union formation, which is essentially the same as the Paskapoo formation of Alberta and is practically continuous with the Fort Union of the United States. Barnum Brown * published a paper in 1914, already mentioned in another connection, which presented the results of his studies for a number of years of the Edmonton formation of the Red Deer River region of Alberta. The splendid section exposed for a distance of 300 miles along this river cuts successively through the Paskapoo and Edmonton and well down into the Pierre. The classification adopted was “the latest determination of these forma- tions by the Canadian Geological Survey”’ and grouped the Paskapoo and Edmonton under the “Laramie.” According to Brown, the Edmonton wherever observed was found resting in apparent conformity on the Pierre. The relations between the Edmonton and the overlying Paskapoo were described by Brown as follows: Near the mountains these beds (Paskapoo), according to Tyrrell, appear to rest conformably on the Pierre shales. On the Red Deer River and elsewhere they are separated from the underlying brackish-water Edmonton beds by a widely distributed coal seam of varying thickness. No other sign of unconformity has been recognized, but a considerable time elapsed between the cldse of the Ed- monton and the beginning of the Paskapoo—a time in- terval represented by all or the greater part of the Lance. No dinosaurs are found in these beds, and the abundant and varied dinosaurs of the underlying Edmonton forma- tion are an older facies than those of the Lance. The several lines of paleontologic evidence were discussed somewhat at length, especially the vertebrate evidence, in which Brown is a specialist. Concerning the dinosaur fauna he said: The vertebrate fauna is distinct from that of the Lance, and few species are common to the two formations. Most of the Edmonton genera are structurally more primitive than those of the Lance, and several genera not found in the Lance are common to the Judith River. The faunal facies, as a whole, is intermediate but closer to that of the Judith River formation than to the Lance. * * * The 83 Idem, p. 153. 6 Cretaceous Eocene correlation in New Mexico, Wyoming, Montana Alberta: Geol. Soc. America Bull., vol. 25, pp. 355-380, 1914. 48 dinosaur fauna forms a series of successive genera, the | phyletic relationship of which is determined by the evolutionary development of skeletal parts, and there is no break in this series from its first appearance low down in the Cretaceous to the final disappearance of the entire group in what we propose to call the close of the Cretaceous, The invertebrates were submitted to T. W. Stanton, who commented as follows: I have recently examined your invertebrates from the Edmonton and Paskapoo formations of Alberta. Those which you have already sent from the Edmonton beds include several lots of brackish-water shells, with aslighter ' mixture of marine forms (Lunatia), and several lots. of purely fresh-water shells. The brackish-water collections are certainly Cretaceous and consist of species which all occur either in identical or very closely related forms in both the Judith River and in the brackish-water bed which occurs at the top of the Fox Hills and the base of the Lance. The fresh-water collections contain no species charac- teristic of either the Judith River or the Lance, and while some of them, like Goniobasis tenwicarinata, occur in the Lance, the general aspect of the fossils is somewhat mofe suggestive of [Fort Union than of anything earlier. It should be remembered, however, that Whiteaves has re- ported a number of] Fort Union species as occurring in the Belly River beds of Alberta, and it may be that more of these types than we have supposed range down as low as the Judith River.“ ’ The fossil plants were studied by Arthur Hollick and me and pronounced to be of Fort Union age, though a small collection from the lower part of the Edmonton submitted to me at a later date appeared to be of Cretaceous affinity. As regards the age of the Edmonton, Brown. said: ‘The Edmonton formation differs greatly in lithologic character from the Fox Hills, which occupies the same relative position in the United States, where it isa sand- stone formation, but I believe it to have been, in part at least, synchronous with the Fox Hills. It may possibly be correlated with the Laramie, according to its original definition. In a later paragraph he added: The strata (Edmonton) are of marine and brackish- water origin and everywhere conformably overlie the marine beds below. The shale series shows an inter- rupted successive sedimentation from purely marine con- ditions at the base, through brackish water during most of the period, with a gradual freshening toward the top. This formation fulfills the original definition of the term Laramie.” 6 The words in brackets, which were omitted from Brown’s paper through an error in transcription or in printing, were supplied by Mr. Stanton in a personal communication to me. 6 Knowlton, F. H., Cretaceous-Tertiary boundary in the Rocky Mountain region: Geol. Soc. America Bull., vol. 25, p. 337, 1914. 67 Brown was in error on this point, for, according to King’s original definition, the Laramie is the ‘uppermost member of the conformable Cretaceous series above the Fox Hills.” LARAMIE FLORA OF THE DENVER BASIN. According to Brown, the Paskapoo forma- tion, as already mentioned, was conformable en the Edmonton, though he thought there was a time interval between them, as shown by the absence of all or nearly all of the Lance formation. The Paskapoo, although contain- ing no dinosaurs, has a small mammal fauna, which, he said, ‘‘is more varied than that of the Lance and is comparable to it.” A late word onthe correlation of the Edmon- ton with beds in the United States is spoken by Eugene Stebinger® in his paper on ‘‘The Montana group of northwestern Montana.” The uppermost member of the Montana group recognized was here called the Horsethief sandstone, which is the equivalent of the Fox Hills as identified by G. M. Dawson in Alberta. Stebinger’s conclusion was as follows: Above the Horsethief sandstone in the section on Two Medicine River there are light-colored soft clayey and sandy strata, already referred to as of continental origin, that are identical in appearance with the Belly River and Judith River strata. Although these rocks’ are younger than Montana in.age, they deserve mention here because they seem to complete for a third time a cycle of sedimen- tation proceeding from purely marine to fresh-water or continental conditions. The first of these cycles is from the marine Colorado shale, through Virgelle sandstone, to the strata of continental origin in the lower part of the Two Medicine formation; the second is from the marine shale of the Claggett, through the sandstone in its upper part, to strata, also of continental origin, comprising the Judith River formation; and the third is from the marine Bearpaw, through the Horsethief sandstone, to the conti- nental deposits above that sandstone. The relations in each cycle between the continental deposits and the underlying sandstone seem to be identical. The strata are apparently perfectly conformable, and the impression is very strong that the same conditions ruled in each transition from marine to land conditions, or, in other words, the strata above the Horsethief sandstone are physically as closely related to the Bearpaw shale as the Judith River formation is to the Claggett or the Two Medicine formation to the Colorado shale. Now, these strata of continental origin above the Horsethief sandstone constitute the St. Mary River beds of Dawson, which occupy the same position in the geologic column as the Edmonton formation of central Alberta and approxi- mately that of the Lance formation of Wyoming. “LARAMIE” AND LIVINGSTON FORMATIONS IN MONTANA. The area in the vicinity of Livingston, Mont., and extending thence southward to the northern border of the Yellowstone Na- tional Park and northward around the Crazy 6 U.S, Geol, Survey Prof. Paper 90, p. 68, 1914. HISTORICAL REVIEW OF Mountains has proved to be of much geologic interest. A number of short reports and news- paper and magazine articles regarding this area had appeared prior to 1871, but they were devoted mainly to descriptions of scenic features and contained little or no geologic information. In 1871 F. V. Hayden ® began his investigations in the Yellowstone National Park and incidentally described the geology of the area between Fort Ellis and what is now the north line of the park. He noted the presence of both Cretaceous and Tertiary rocks in the area. In the same report” Lesquereux described the fossil plants obtained by the Hayden parties, referring those found 6 miles above Spring Canyon; on High Ridge, about 10 miles west of Hot Springs; and at Yellowstone I.ake, among basaltic rocks, to the Eocene, while those from the mouth of Spring Canyon were not definitely placed. In the following year the exploration of he Yellowstone National Park was continued by the Hayden Survey, and A. C. Peale ™ reported on the geology of the area between Fort Ellis and the Yellowstone \Valley and thence up the Yellowstone to the park. He also noted the presence of Cretaceous and Eocene, the latter on the basis of the deter- minations of the fossil plants by Lesquereux. In 1878 Lesquereux” published his ‘‘Ter- tiary flora,” in which he brought together all the species of plants—329 in number—which he then considered as belonging to the flora of the ‘‘Lignitic.” The beds at the localities near Fort Ellis, above Spring Canyon, and at Yellowstone Lake he referred to his so-called ‘first group,’ which he considered as of Eocene age. The species from the locality at the mouth of Spring Canyon were not alluded to, as they were, at least by inference, con- sidered as Cretaceous. In 1886 the final report of the Tenth Census of the United States relating to the mineral resources, exclusive of the precious metals, was published under the general direction of Raphael Pumpelly. It embraced reports by Waldemar Lindgren” and George H. Eld- 6 U.S. Geol. Survey Terr. Fifth Ann. Rept., for 1871, pp. 1-165, 1872. 70 Tdem, pp. 296-300. 1 U.S. Geol. Survey Terr. Sixth Ann. Rept., for 1872, pp. 108 et seq., 1873. ; 1 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 7, 1878. #8 U.S. Tenth Census, vol. 15, pp. 743-746, 1886. 49 THE LARAMIE PROBLEM. ridge ™ on the geology and coal resources of Montana, and each contained data bearing more or less directly on the present problem. Lindgren reported especially upon the section from the Bull Mountains to Musselshell River and referred the immense thickness of nearly 10,000 feet of beds above the Fox Hills to the Laramie, which he divided into a ‘‘Lower Laramie” and an ‘‘Upper Laramie,”’ the latter being recognized as the Fort Union. The so-called Bozeman coal field was de- scribed by Eldridge. He presented a section of the rocks (LVI, fig. 2) through this field, beginning with the Jurassic and including the Dakota, Benton, and Niobrara and of course the coal-bearing rocks. The coal-bearing rocks were not definitely referred to the Laramie, though they were obviously considered as be- longing init. As regards the stratigraphic rela- tions of the coal measures, Eldridge wrote as follows: - 3 There is another most important peculiarity in the be- havior of the principal coal seams, noticed in the eastern portion of the field. The surface of the ground on which the coal bed was originally laid down is most irregular. For a length of 2 miles at least, and for an undetermined _width, but presumably covering quite an area altogether, the surface was covered by gentle undulations in the form of knolls, of varying and irregular dimensions, oftentimes extensive, oftentimes a few feet only either way, with no definite arrangement of the axes. In the hollows of these, overlapping some and only coming up on the sides of others, the material subsequently to be converted into coal was laid down, and finally came the roof of sandstone, capping the whole. These irregularities have furthermore been increased by disturbances in certain parts, which have caused both rock and coal to be slickensided and rendered it extremely friable. In the same year (1886) Lester F. Ward” briefly alluded to the plants from the Hayden - locality known as ‘6 miles above Spring Canyon, near Fort Ellis, Mont.,” and from several places in the Yellowstone Park. He sald: These plants are all classed by Mr. Lesquereux in his first or lowest group as true Laramie, but upon careful investigation I am tolerably well satisfied that they belong to the Fort Union deposits. . In 1891 Walter H. Weed ” published a short paper on “The Cinnabar and Bozeman coal fields of Montana,” in which he described in 14 Idem, pp. 739-743. : 75 Synopsis of the flora of the Laramie group: U.S. Geol. Survey Sixth Ann. Rept., p. 741, 1886. : 76 Geol. Soc. America Bull., vol..2, pp. 349-364, 1891. 50 some detail the coal measures of these areas. His conclusions concerning their age were set forth as follows: While the evidence presented in this paper is not con- sidered conclusive, and while the work upon the district is not far enough advanced to warrant a final statement, yet it is believed that the facts show that the coal measures of the Cinnabar and Bozeman coal fields are probably of Laramie age, occurring at the very base of the Laramie series, and that they are conformably overlain by a totally different series of rocks, composed entirely of volcanic material and containing an abundant fossil flora of recog- nized Laramie types, in turn overlain by beds of fresh- water clays and sandstones of undetermined age but be- longing to what has heretofore been considered as undoubt- edly Laramie strata. / The Livingston formation was named by Weed” in 1893 from its typical development near the town of Livingston, Mont. For the decade or more preceding the publication of this paper the great thickness of rocks in this region above the supposed Montana Cretaceous had been very generally regarded as Laramie. Weed said: Measured sections of the strata about the Crazy Moun- tains show a thickness of 12,000 feet of fresh-water sand- stones and clays referred to the Laramie. It is now possi- ble to subdivide this great thickness of beds into Laramie, a higher horizon herein named the Livingston, and the’ still higher beds of the Crazy Mountains, which have not as yet been differentiated into horizons but probably represent the Fort Union beds of eastern Montana. It was thought by Weed and later by others that ‘these beds present proof of a series of events following the epoth of the coal-making Laramie similar to those described by Whitman Cross, in Colorado, of which the Arapahoe and the Denver beds are the evidence.”’ Weed’s description of the Mesozoic section ‘ began with the Jurassic, above which is what he, following previous workers in the field, called the Dakota, which, he said, ‘forms the most persistent and readily recognizable horizon - of the Rocky Mountain Mesozoic.” Above the beds identified as the Dakota are over 3,000 feet of shales, in many places carbonaceous, and interbedded sandstones, that he divided about equally between the Colorado and the Montana, though he stated that “a satisfactory discrimination between the beds of the Colo- rado and those forming this group (Montana) 17 Weed, W. H., The Laramie and the overlying Livingston formation in Montana, with report on flora, by F. H. Knowlton; U. S. Geol. Survey Bull. 105, pp. 1-68, 1893. 78 Idem, p. 11. LARAMIE FLORA OF THE DENVER BASIN. can not be made on paleontologic grounds, as few fossils have been collected in the beds assigned to the Montana.” The Fox Hills was not definitely recognized, though Weed said: “In the eastern part of the field the dark-gray sandy shales [of the Montana] are directly overlain by a heavy, ledge of yellow, rather dark, and very massive sandstone, which is thought to be the equivalent of the Fox Hills sandstone.” Conformably above this is the Laramie as then recognized. It is about 1,000 feet in thickness and is composed of massive light-colored sandstones with intercalated shale beds and coal seams. ‘The upper limit of the ‘Laramie in the region studied is marked by an abrupt change in ‘the composition of the beds and closely resembles in general charac- teristics that change which has been found so prominently developed in Colorado.” The Livingston was described by Weed as follows: e Overlying the coal-bearing Laramie strata there is a series of beds constituting a newly recognized formation, for which the name Livingston is proposed, asitis typically developed in the vicinity of Livingston. This formation consists of a sefies of beds, in places aggregating 7,000 feet in thickness, composed of sandstones, grits, conglomerates, and clays, made up very largely of the débris of andesitic lavas and other volcanic rocks and including local inter- calations of volcanic agglomerates. The Livingston formation was believed by Weed to rest unconformably on the Laramie, and the basis for this belief was set forth at length in the paper under consideration. The upper part of the Livingston was said to pass without observed stratigraphic break into the overlying beds then presumed and since proved to belong to the Fort Union formation. The fossil plants of the Bozeman coal field and adjacent areas were considered by me in Weed’s report above cited,” in a more formal presentation of the facts published the pre- ceding year. The fossil flora, as then known, embraced 44 species, and the conclusion was reached that the plants from the coal-bearing beds belong “to what is generally known as the Laramie,” while ‘the flora of the Livingston formation finds its nearest relationship with the flora of the Denver beds of Colorado.” 7 Knowlton, F. H., Annotated list of the fossil plants of the Bozeman, Mont., coal field, with table of distribution and description of new species: U. S. Geol. Survey Bull. 105, pp. 43-66, pls. 5, 6, 1893. 80 Knowlton, F. H., The fossil flora of the Bozeman coal field: Wash. ington Biol. Soc., vol. 7, pp. 153, 154, 1892. HISTORICAL REVIEW OF THE LARAMIE PROBLEM. In 1894, in the Livingston folio, Weed * described and mapped the several formations under discussion with the signification and limits given to them in the bulletin above cited. In 1896 the Three Forks quadrangle, which adjoins the Livingston, quadrangle on the west, was described in a folio by A. C. Peale.” He accepted the Dakota, Colorado, Montana, Laramie, and Livingston formations as defined by Weed and wrote of the Laramie as follows: The formation consists essentially of light-gray or whitish sandstones, with interlaminated argillaceous beds, some of which are locally much indurated. The two areas in which the strata are best exposed are in the Nixon basin, north of the Gallatin Valley, and in the Gallatin basin, lying between the Gallatin and Madison ranges. The total thickness of the formation is from 800 to 1,000 feet. In the Nixon basin Unios and other fresh-water shells are found in connection with the coal. Concerning the Livingston formation he said: The Livingston formation occupies at the present time comparatively little area within the limits of the Three Forks sheet, and nowhere is it likely that the entire thickness of the formation is shown. The largest area is probably that in the vicinity of the Sphinx Mountain, where the Sphinx conglomerate rests unconformably upon - it. This area is about 15 to 20 square miles in extent, and the deposits are made up of a mass of volcanic materials indistinctly bedded, mostly andesitic in nature, and of a somber hue. At one or two places conglomerates made up of all sorts of volcanic pebbles are seen near the base. This generally black mass rests unconformably upon the eroded surfaces of the previously deposited Cretaceous formations, contrasting strongly in color with the Laramie sandstones and the Dakota conglomerates, with both of which it is in contact at different points. The unconformable relation near Sphinx Mountain described. by Peale, which was known to Weed, was one of the factors upon which Weed based his contention of an un- conformity between so-called Laramie and Livingston. Weed ® published in 1896 a short paper. which was devoted mainly to the Fort Union, with only incidental mention of the Laramie and Livingston formations. The immense section of strata forming the eastern foot slopes of the Crazy Mountains on Lebo Creek, Mont., was divided as follows: Laramie, 1,080 |- feet; Livingston, 7,136 feet; Fort Union, 4,649 feet. “a Weed, W. H., U. S. Geol. Survey Geol. Atlas, Livingston folio (No. 1), 1894. 82 U.S. Geol. Survey Geol. Atlas, Three Forks folio (No. 27), 1896. 83 Weed, W. H., Am. Geologist, vol. 18, pp. 201-211, 1896. ol The Little Belt Mountains quadrangle, im- mediately north of the Livingston quadrangle, was described by Weed * in 1899. The Da- kota, Colorado, and Montana were grouped together in the Yellowstone formation, which was said to be followed conformably by the Laramie formation. The Laramie was de- scribed in much the same terms and assigned the same thickness as in the Livingston and Three Forks folios. The Livingston, believed to rest unconformably on the Laramie, was described at considerable length and was given a maximum thickness of 7,000 feet. In the text of the folio the Livingston was placed under the heading “Rocks of the Cretaceous period,”’ and in the generalized section of the sedimentary rocks of the Crazy Mountains it was given as ‘Cretaceous?’ Although in- | cluded with the Livingston formation in map- ping, the upper 4,000 feet of beds were in the columnar sections differentiated as the Fort Union. The, next paper in chronologic order is one by Earl Douglass,** published in 1902, entitled ‘‘A Cretaceous and lower Tertiary section in south-central Mont&na,”’ in which the inter- pretation. was radically different from that given by Weed. The area covered by this paper lies east of the Crazy Mountains and south of the Big Snowy Mountains, in the basin of Musselshell River. The section, according to Douglass, comprises the following units: Tertiary. ....Fort Union. Laramie. Fox Hills. Pierre. Fish Creek beds. Niobrara. Benton. Cretaceous. . The Livingston formation was not recog- nized in this section, although the locality is only a few miles from the Lebo Creek section recorded by Weed, in which it was given a thickness of over 7,000 feet. Douglass appar- ently included the Livingston in whole or in major part within the so-called Laramie, con- cerning which he wrote as follows: What is supposed to be Laramie in the present section is very thick, probably approximately that of Lindgren’s measurements [7,000 feet]. But here, as everywhere else, the boundaries of the Laramie are uncertain. Here, 81 Weed, W. H., U. S. Geol. Survey Geol. Atlas, Little Belt Moun- tains folio (No. 56), 1899. 85 Am. Philos. Soc. Proc., vol. 41, pp. 207-224, 1902. 52 however, we have it confined between certain limits. We have it above a characteristic Fort Pierre fauna and below a characteristic Fort Union flora. Just how much of that which intervenes is Laramie is not known. On another page he added: We found here no traces of the volcanic material of the Livingston formation, which only 30 or 40 miles to the southwest is so well developed. : Part of the same area was examined in 1903 by Stanton and Hatcher,*° whose report was published in 1905. They were, however, more concerned in the elucidation of the: Montana group, the classification of which, as will be subsequently shown, has played an important part in the Laramie-Livingston controversy, and they made only incidental mention of the higher beds. Concerning these they said: South and west of Fish Creek these shales [Bearpaw] are overlain by marine Cretaceous sandstones and by a thick series of beds.that have been referred to the Laramie, Livingston, and Fort Union formations. The generalized section for central and north- ern Montana as worked out by Stanton and Hatcher is.as follows: . & o Laramie (?). Fox Hills (?). Bearpaw. Judith River. Claggett. Eagle. Montana group. Colorado group. Benton. Dakota (?). In 1906 R. W. Stone *’ studied the strati- graphy .and coal resources of an area of ap- proximately 1,000 square miles in central Montana, extending from Shawmut westward to the head of Musselshell River and southward in the Shields River valley to the town of Clyde Park. er part of the Laramie, is about 350 feet above what is believed to be the Arapahoe con- glomerate. This conglomerate is about 50 feet thick. It also appears that the Scranton coal is more than 400 feet above beds that can with reasonableness be referred to the Laramie, and more than 1,000 feet above the main Laramie coal. The thickness of beds between the Scranton coal and the main Laramie coal is not of particular significance in view of the fact that the maximum thickness previously as- 104 signed to the Laramie in this area was about 1,600 feet. The crucial point is the disclosure of the Arapahoe conglomerate between the two coal horizons, which naturally tends to decrease the observed thickness of the Laramie strata. The other supposed locality for Arapahoe plants—namely, that near the Douglas coal mine, west of Sedalia—may now be considered. As this is at or near the type locality for the Arapahoe there should apparently be no ques- tion as to its relation, but it appears from the work of G. B. Richardson, who critically stud- ied this area in 1910-11, that the Arapahoe occupies the stratigraphic position of the Daw- son arkose and in fact interdigitates with the lower part of it. Concerning this point Rich- ardson ** wrote as follows: ‘It was found that the lower part of the Dawson arkose seems to pass along the strike into the Arapahoe and Denver formations; that the Dawson and Arapahoe can not be separated lithologically, even at the type locality of Arapahoe, on the bluffs of Willow Creek.’’ This conclusion does not, of course, affect the stratigraphic relations of the plant-bearing beds, and it is unimportant whether the beds are to be called Arapahoe or Dawson, as they are separated from the under- lying Laramie by an unconformity marking a considerable time interval. Below is a tentative list of the plants from the Douglas mine locality as worked up about 12 years ago. Additional material not yet studied may necessitate slight changes, though it is not presumed that these will greatly affect the result. Acer trilobatum productum. Asplenium erosum. Berchemia multinervis. Cissus laevigata. Cissus lobato-crenata. Dicksonia, new. Diospyros brachysepala? Dombeyopsis obtusa. Dombeyopsis, new. Dryopteris lakesii. Dryopteris lesquereuxii? Ficus planicostata. Ficus, new. Hicoria? sp. Laurus primigenia. Nelumbo lakesii. Nelumbo, new. Phyllites, new. Quercus, new. 14 Richardson, G. B., The Monument Creek group: Geol. Soc. America Bull., vol. 23, p. 274, 1912. LARAMIE FLORA OF THE DENVER BASIN. Viburnum, new. \ Woodwardia latiloba. It will be seen at once that this is essentially a Denver flora, with only two species that occur in the Laramie—Dombeyopsis obtusa and Ficus planicostata. . Both of these species. have already been several times mentioned as passing from Laramie into post-Laramie beds. RELATIONS TO THE LANCE FORMATION. It is difficult at present to make an accurate and wholly satisfactory comparison between the flora of the Laramie in the Denver Basin and the flora of the Lance formation. This difficulty arises from the fact that the Lance flora has not yet been thoroughly worked up and described. It is known that the Lance flora comprises approximately 125 forms. It is possible that when this flora has been fully described, the number of species found to be in common with the Laramie may be slightly increased over the number given below, but it is improbable that they will be increased to as many as twice that number. Another diffi- culty in the way of making an accurate com- parison between these two floras is the uncer- tainty that still attaches té certain of the locali- ties that have afforded some of the supposed Lance plants. It is perhaps unnecessary to state that there has been—and indeed still is— more or less uncertainty in fixing the limits of the Lance formation, though the difficulty is much greater in fixing the upper limit than it is in fixing the lower limit. Be this as it may, the species mentioned below are the only ones that are at present recognized as passing from the Laramie into the Lance. Equisetum perlaevigatum. Myrica torreyi. 2 Ficus planicostata. Cinnamomum affine?? Rhamnus salicifolius. Platanus platanoides. Quercus viburnifolia? A discussion of these species may be of interest. Thus, Equisetum laevigatum (now perlaevigatum) was reported by Hollick from the so-called “Hell Creek beds”? (Lance) in the vicinity of Hell Creek, Mont. In the de- scriptive part of this paper (p. 113) it is stated that this species was founded on two speci- mens, one of which (from Sand Creek, Colo., in beds now believed to be of Denver age) is THE FLORA. probably only a piece of bark, and the other (from the true Laramie at Golden, Colo.) is based on a portion of an underground stem of an Equisetum with characters so poorly defined that the advisability of retaining it is open to question. that there are Hquisetum stems in the “Hell Creek beds,” but the propriety of identifying them with Equisetum perlaevigatum may well be questioned. Rhamnus salicifolius is an- other of the forms identified by Hollick in the “Hell Creek beds.” This, together with Myrica torreyi, is well known as a species en- joying a wide vertical range. Ficus plani-. costata is also a species of considerable ver-— tical range. It is extremely rare in the Lance. formation, and its identification is not be-' yond question. The identification of Cinna- momum affine rests on its doubtful presence in ' the Kingsbury conglomerate, east of the Big: Horn Mountains, Wyo., and Quercus viburni-' folia was identified with question at Forsyth, Mont. In a paper published in 1909'* I listed 11 species that were at that time believed to be common to the Laramie and Lance forma-. tions. The species additional to those in the, above list are Ficus trinervis, Flabellaria , eocenica, Sabalites grayanus, and Juglans' rugosa. According to present understanding! neither Ficus trinervis nor Juglans rugosa is: known in the Laramie of the Denver Basin. ' The two palms may be the same as the Mon-, tana and Laramie form known as Sabal: montana, but there is usually difficulty in cer- tainly identifying remains of palms. From this brief account it appears that’ there are not now known to be more than: four or five species of plants that are common; to the Laramie and Lance, and when it is' recalled that there is about the same number: of species in the two floras, it is seen that the relationship between these floras is not a: strong one. RELATIONS TO THE UPPERMOST CRETACEOUS. OF THE ATLANTIC COASTAL PLAIN. t In the major portion of the Atlantic Coastal Plain the uppermost Cretaceous is believed to 16 Knowlton, F. H., Stratigraphic relations and paleontology of the “Hell Cree’x beds,”’ “ Ceratops beds,” and equivalents, and their refer- ence to the Fort Union formation: Washington Acad. Sci. Proc., vol. “11, p. 222, 1909. It is not to be doubted |. 105 be either lower in position than the Laramie, or where the section is more nearly com- plete—as in the northern portion—it is a marine deposit and not plant-bearing. RELATIONS TO THE PATOOT SERIES OF GREENLAND. The Cretaceous system is very considerably developed in Greenland, reaching a thickness of approximately 4,000 feet. The area of exposure includes Disco Island and the Nug- suak Peninsula and is a belt about 75 miles wide along the deeply indented coast line from latitude 69° 15’ to 72° 15’ N. The beds | at many places are very fossiliferous and have yielded altogether more than 350 species of plants, which were, in the main, elaborated | by Oswald Heer in his well-known “Flora — fossilis arctica,” comprising seven quarto volymes, published in 1868 to 1883. On the basis of the plants, Heer divided the Cre- taceous into three series. A lower division, | called the Kome series, with a flora of 88 species, was correlated with the Urgonian of Europe; a middle division; the Atane seriés, with 177 species of plants, was correlated with the Cenomanian; and an upper division, the Patoot series, with a flora of 123 species, was correlated with the European Senonian and the Fox Hills of the United States. Above || this in other parts of the Arctic region is a con- siderable thickness of Tertiary beds, also with an abundant flora, which constitute the so- called Arctic Miocene, now very generally re- ferred to the Eocene. The Atane and Patoot series have a com- bined thickness of at least 1,300 feet, and probably considerably more. There is no sharp line of demarcation between them, the boundary having been drawn by Heer purely on paleohtologic grounds. Although Heer definitely correlated the Patoot series with the Senonian, White and ‘Schuchert,"* who visited the region in 1897, ‘| expressed the view that there was a transition without sedimentary break into the overlying Tertiary. These writers also stated that the '| Patoot series contains ‘“‘many-plants common to the upper part of the Amboy clays, with others allied more closely to the higher Cre- taceous flora, such as that of the Laramie.” 18 White, David, and Schuchert, Charles, Cretaceous series of the west coast of Greenland: Geol. Soc. America Bull., vol. 9, p. 367, 1898. 106 Subsequent study of the Laramie flora. however, does not bear out this suggestion, for so far as now known the two floras contain no species in common. This is also the view reached by Berry,” who pointed out that of the 123 Patoot species 20 occur in the Dakota sandstone, 22 in the Raritan, 19 in the Mago- thy, 8 in the Tuscaloosa, and 4 in the Black Creek formation. He says: “The large num- ber of Atane species present (34), as well as the numerous Dakota, Raritan, and Magothy species, precludes considering the flora as young as, for example, the Laramie.” It may be accepted, then, that the Laramie flora is younger than that of the Patoot series and there is little or no relation between them. RELATIONS TO, THE UPPER CRETACEOUS OF : EUROPE. As a preliminary to the consideration of the possible relations between the flora -of the Laramie and such-floras as are available in the European Upper Cretaceous, it may be of interest to give a brief tabular view of the Upper Cretaceous section that is now quite generally accepted. It is taken in the main from the fifth edition of De -Lapparent’s Geology: Danian. i : ; Aturian{Macstrichtian yp per Senonian. Campanian. : Lower Senonian. Emecherian (onrona Coniacian Angoumian. Ligerian. Cenomanian. — Turonia: The Campanian, the lower division of the Aturian (Upper Senonian), is thought to correspond approximately to the Pierre shale and the Fox Hills sandstone of the United States. The Maestrichtian, which constitutes the upper division of the Aturian (Upper Senonian), together with the Danian, corre- sponds to the Laramie, at least in position. The Maestrichtian is abundantly plant-bearing at a number of localities, especially in the Minster Basin of Westphalia. The plants from these localities—Sendenhorst, Haldene, Lunfiide, etc.—were studied and described . VW Berry, E. W., Maryland Geol. Survey, Uprer Cretaceous, p. 196, 1916. ! LARAMIE FLORA OF THE DENVER BASIN. specially by Hosius*® and by Hosius and Von der Marck.” E. W. Berry,” in a chapter on the Upper Cretaceous floras of the world, has compiled a complete list of the Maestrichtian flora of the Minster Basin, which is as follows: Apocynophyllum cuneatum Hosius and Von der Marck. Apocynophyllum subrepandum Von der Marck. Aralia denticulata Hosius and Von der Marck. Cf. Ceanothus sp. Chondrites furcilentus latior Von der Marck. Chondrites intricatus Sternberg. Chondrites jungiformis Debey and Ettingshausen. Chondrites polymorphus Hosius and Von der Marck. Chondrites subcurvatus Hosius and Von der Marck. Comptonia tenera Hosius and Von der Marck. Cunninghamites elegans (Corda) Endlicher. Cunninghamites squamosus Heer. Dewalquea gelindensis Saporta and: Marion. Dewalquea haldemiana Saporta and Marion. Dewalquea haldemiana angustifolia Hosius and Von der Marck. Dewalquea haldemiana latifolia Hosius and Von der Marck. : Dewalquea insignis Hosius and Von der Marck. . Dryandroides haldemiana Hosius and Von der Marck. . Dryandroides macrophylla Hosius and Von der Marck. Eolirion? nervosum Hosius and Von der Marck. Eolirion primigenum Schenck? Eolirion? subfalcatum Hosius and Von der Marck. Eucalyptus haldemiana Debey. Eucalyptus inaequilatera Von der Marck. Ficus angulata Hosius and Von der Marck. Ficus densinervis Hosius and Von der Marck. Ficus laurifolia Hosius and Von der Marck. Frenelopsis kénigii Hosius and Von der Marck. Haliserites contortuplicatus Von der Marck. | Laurus affinis Hosius and Von der Marck. Myrica leiophylla Hosius and Von der Marck. Myrica primaeva Hosius and Von der Marck. Cf. Myrtophyllum cryptoneuron Saporta and Marion. Nerium rohlii Von der Marck. Cf. Oreodaphne apicifolia Saporta and Marion. Osmunda haldemiana Hosius and Von der Marck. Pinus monasteriensis Hosius and Von der Marck. - Populus tremulaeformis Hosius and Von der Marck. Pisidonia cretacea Hosius and Von der Marck. Quercus asymetia Hosius and Von der Marck. 18 Hosius, A., Die in der Westfilischen Kreideformation vorkommen den Pflanzenreste Minster, pp. 1-34, 1869; Ueber einige Dicotyledonen der Westfilischen Kreideformation: Palaeontographica, vol. 17, pp. 89-104, pls. 12-17, 1869. 19 Hosius, A., and Von der Marck, Die flora der Westlalischen Kreide- formation: Palaeontographica, vol. 26, pp. 125-256, pls. 24-44, 1880. 20 Maryland Geol. Survey, Upper Cretaceous, p. 283, 1916. ‘THE FLORA. Quercus castanoides Hosius and Von der Marck. Quercus dryandraefolia Von der Marck. Quercus euryphylla Hosius and Von der Marck. Quercus formosa Hosius and Von der Marck. Quercus heiracifolia Hosius and Von der Marck. Quercus iliciformis Hosius and Von der Marck. Quercus rhomboidalis Hosius and Von der Marck. Quercus sphenobasis Hosius and Von der Marck. Quercus westfalica latior Hosius and Von der Marck. Quercus westfalica oblongata Hosius and Von der Marck. : Quercus westfalica obtusata Hosius and Von der Marck. Cf. Rhamnus sp. Sequoia reichenbachi (Geinitz) Heer. Taenidium alysoides Hosius and Von der Marck. Tetraphyllum dubium Hosius and Von der Maick.: Thalassocharis westfalica Hosius and Von der Marck. : This flora comprises, 56 forms, only one of which, Sequoia reichenbacht, is found in the Laramie. This is without special significance, for this species enjoys a world-wide distribu- tion and ranges in age from Jurassic to upper- most Cretaceous. A number of genera, such as Ficus, Laurus, Myrica, Populus, and Quercus, are common to the two, but the species are alli perfectly distinct and apparently unrelated. It appears to the writer that the Maestrichtian flora is much more closely related to the Montana flora. the common presence of certain conifers, such as Cunninghamites, Frenelopsis, and Sequoia reichenbachi. Be this as it ‘may, the Mae- strichtian certainly has no particular relation- ship with the flora of the Laramie. THE FLORA. Phylum THALLOPHYTA. Delesseria fulva Lesquereux. Plate I, figure 4 (type). : ‘Delesseria fulua Lesquereux, U. S. Geol. and Geog. Sur- vey Terr. Ann. Rept. for 1872, p. 376, 1873; idem for 1873, p. 379, 1874; idem for 1876, p. 496, 1878; Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 39, pl. 1, fig. 10, 1878. [Lesquereux’s original figure of the type is here reproduced.] The type of this species is No. 9 of the United States National Museum collection of fossil plants and. appears to be the only example ever obtained. It is preserved on a fine- grained hard white sandstone, on which it stands out in bold relief, being itself of a reddish-brown color. This is especially shown by. 107 Golden, Occurrence: Laramie formation, Colo., under or between coal beds. Phylum PTERIDOPHYTA. Order FILICALES. Family POLYPODIACEZX. Onoclea fecunda (Lesquereux) Knowlton. Plate L, figures 2, 3. Caulinites fecundus Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 384, 1873; idem for 1873, p. 380, 1874; idem for 1876, p. 501, 1878; Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 101, pl. 14, figs. 1-3, 1878. [Les- quereux’s original figures are here reproduced.] Onoclea fecunda (Lesquereux) Knowlton, U. 8. Geol. Survey Bull. 152, p. 153, 1898. Fertile frond contracted, closely pinnate; main rachis broad (2 millimeters), smooth, divided into opposite erect branches which bear on each side thickly set short-pediceled simple spherical “capsules” (sporangia) ; sterile portion not known. The type specimens of this plant are pre- served in the United States National Museum (Nos. 120, 121). Their original reference to the genus Caulinites was a matter of uncer- tainty, for Lesquereux in his first mention says, “This relation to species of our time is unknown,” and later # adds: It is very questionable if these fine fruiting branches may be referred to.this genus. They have this in common only—a, monospermous (?) nucula with a cellulose enve- lope. As I have been unable to find either in the fossil species described until now or in the collection of living plants which I was able to consult anything to which they had apparent relation, I have left them in this as yet vaguely defined genus. No additional material has been obtained since that described by Lesquereux, and it is perhaps hazardous to transfer these specimens to another genus, but all things being taken into account, the suggestion of the late Joseph F. James™ that they closely resemble the fruiting frond of the living Onoclea sensibilis seems to justify the change. When the fossil and living plants are placed side by side it is seen that the resemblance is striking and suggestive. The fossil has the same pinnate branching and opposite, contiguous, short- 2U.S. Geol. and Geog. Survey Terr, Ann. Rept. for 1872, p. 384, 1873. 2 The Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 101, 1878. 23 Science, vol. 3, p. 433, fig. la, 1884. 108 pediceled ‘“‘capsules” as the living species. The living form, as is well known, has the fertile pinnules rolled up into berry-like bodies, on the outside of which thick veins are very prominent. In the fossil this feature is appar- ently absent. Considering the fact that this fruiting portion has been found only once, it is not strange that the sterile portion remains unknown. A species that has a somewhat similar history has been found in the Raritan and Magothy formations of southern New York and the islands south of the New England mainland. It was first described as Caulinites inquirendus Hollick * and later transferred to Onoclea® on the ground of its resemblance to the species under consideration. Like our form, it has pinnately arranged branches with the spheroi- dal “capsules” in a single row on each side, and associated sterile fronds have not been found. with it. One of the most abundant and widely dis- tributed plants of the Fort Union formation is a fern that can not be distinguished from the living sensitive fern, Onoclea. sensibilis. It occurs at some localities by hundreds, but in only one known place in all the vast area covered by the Fort Union formation has it been found fruiting. In a small collection obtained near Porcupine Butte, Sweetgrass County, Mont., there were many of the usual sterile fragments, and associated with them a few fertile fronds.” fertile fronds with the Laramie specimens under consideration shows a close, at least generic. similarity. Thus, as at present provisionally marked out, our knowledge of the geologic history of the living sensitive fern may stand as follows: Onoclea inquirenda Hollick..... Raritan. Onoclea neo-mexicana Knowl- Montana. _ton. Onoclea fecunda (Lesquereux) Laramie. Knowlton. Onoclea sensibilis fossilis New- Fort Union. berry. Onoclea sensibilis Linné.........Living. % Hollick, Arthur, New York Bot. Gard. Bull, vol. 3, p. 495, pl. 20,' fig. 3, 1904. % Hollick, Arthur, U. S. Geol. Survey Mon. 50, p. 82, rl. 1, figs. 1-7,’ 1906. 26 Knowlton, F. H., Torrey Bot. Club Bull., vol. 29, p. 705, p. 26, figs. 1-4, 1902. A comparison of these. LARAMIE FLORA OF THE DENVER BASIN. Laramie formation, Erie, collected by Leo Les- Occurrence: Boulder County, Colo., quereux about 1872. Dryopteris georgei Knowlton, n. sp. Plate I, figures 6, 7. Fronds probably of large size but the com- «plete outline unknown, though apparently it ‘was at least thrice ‘pinnatified; main rachis not sure; secondary rachis strong, straight, grooved; pinnae apparently lanceolate; pinnules numer- ous, very close, alternate or subopposite, narrowly linear-lanceolate, sessile, natrowly acuminate at apex, cut into numerous small, oblong, rather obtuse lobes, the cutting being made less toward the apex; nervation fairly strong, consisting of a stout midvein and five or six pairs of once-forked veins; fruit not seen. This fine species, which I am able to include by the courtesy of Prof. R. D. George, of the University of Colorado; is all that has been found, and although a considerable portion of the frond is preserved it was evidently of much larger size when perfect. Two of the pinnae are parallel and lie in such a position as to suggest that they were attached to a common rachis, in which case the whole frond must have been of imposing appearance. The pinnae appear to have been 15 or 20 Centi- meters in length and 7 or 8 centimeters in width. The pinnules, as already noted, are narrowly linear-lanceolate, their length being 4 or 5 centimeters and their width about 1 centimeter at base; they begin to narrow near the middle and become narrowly acuminate at the apex. The coriaceous appearance of the frond and its rather strict aspect suggest the probability that it was ef xerophytic habit. The photograph showing the whole frond somewhat less than natural size was sent by Prof. George, who also kindly donated the two fragments of the counterpart shown in figures 6 and 7. . Occurrence: Laramie formation, shaft of Columbia mine, 150 feet from the surface, near Louisville- Junction, Boulder County, Colo., submitted by R. D. George. Type specimen in the Museum of the University of Colorado. Boulder, Colo.; pieces of counterpart in United States National Museum. THE FLORA, Dryopteris laramiensis Knowlton. Plate I, figure 5 (type). Dryopteris laramiensis Knowlton, U. S. Geol. Survey Bull. 696, p. 248, 1919. Lastrea (Goniopteris) intermedia Lesquereux, Tertiary flora: U.S. Geol. Survey Terr. Rept., vol. 7, p. 56, pl. 4, fig. 14, 1878. [Lesquereux’s original figure is here reproduced.] Aspidium (Lastrea) pulchellum? Heer, or A. fischeri? Heer. Lesquereux, U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1870, p. 384, 1872. This species is evidently very closely related to Dryopteris lesquereucii, from which it appears to differ in having the pinnae closer, at a more acute angle of insertion on the rachis, and with : the pinnules or lobes somewhat longer. Neither of these differences is of much i impor- tance, and it is quite possible that a series of apeeimens, if they were available, would show the two forms as merging, but so far as known the specimen figured by Lesquereux is the only specimen extant, and if it were not for some phases of the daria history of the present “species,” it would perhaps do no great harm to combine them. The specimens on which Lesquereux founded Lastrea intermedia are involved in some complications. In the first mention *. (under the designation Aspidium pulchellum Heer, or A. gaclent Heer) they are said by Lesquereux to have come from “ Muddy Creek,”’ without mention of the State or other more exact location. From Hayden’s itiner- ary, which precedes the report on the fossil plants, it appears reasonably certain that they must have come from the Muddy Creek that rises in Bridgers Pass, in the mountains south of Rawlins, in Carbon County, Wyo., and flows into Little Snake River. At a point in the valley of this stream near Barrel Springs Hayden * found, in partion to shells, remains of turtles, fish, etc., “a few Ghecure plants, like blades of grass, stems of rushes, etc., in- the, clays; still higher up on the tops of the hills that border the stream are some thin, chalky clays crowded full of plants, as ferns, rushes, grasses, palms, etc., finely preserved. = It is doubtful if any of this material is present in the collections of the United States National Museum, at least under this designation. In the next mention of Lastrea intermedia by Lesquereux ” it is said to have come from 2 U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1870, p. 384, 1872. 28 Idem, p. 73.. 29 The Tertiary flora: U.S. Geol. Survey Terr. Rept., vol. 7, p. 56, 1878: 85344—22—_8 109° “Henrys Fork, a mixed lot.’”’ It is easy to see how this mistake arose, for in the Annual Re- port for 1870, page 384, the designation ‘Henrys Fork” occurs at the top of the page, while that of ‘Muddy Creek”’ is in the middle of the page without indention or other display and so is easily overlooked. But this error is apparently responsible for Lesquereux’s refer- ence of Lastrea intermedia to the Green River formation, which would doubtless be correct if it had actually come from Henrys Fork. There seems, therefore, absolutely no warrant for Henrys Fork as a locality or Green River formation as a horizon for this species. Golden, Colo., is also given by Lesquereux * as a locality for ‘‘Lastrea intermedia,’ and the only specimen figured is preserved in the United States National Museum. It is pre- served on the hard white sandstone character- istic of the Laramie at this locality and is ap- parently correctly recorded. Owing to the absence of all specimens, except the one'from the Laramie at Golden, the occur- rence of this form in Wyoming will have to be ignored, at least until more material has been procured. Occurrence: Colo. Laramie formation, Golden, Dryopteris lesquereuxii Knowlton. Aspidium goldianum Lesquereux,*? U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1873, p. 398, 1874. Lastrea (Goniopteris) goldiana Lesquereux, Tertiary flora: U.S. Geol. Survey Terr. Rept., vol. 7, p. 56, pl. 4, fig. 13, 1878. Dryopieris lesqueveusté Knowlton, U. S. Geol. Survey Bull. 696, p. 248, 1919. Frond bipinnate (tripinnate %), broadly del- toid in outline; pinnae linear, alternate, parallel, at an obtuse or rarely somewhat acute angle of divergence (40°-50°), alternately and equally pinnately lobed; lobes cut or separated by two- thirds or three-fourths of their length, oblong- lanceolate, obtusely pointed, inclined outside; middle nerve strong, distinct, lateral veins five to seven pairs, curving slightly upward, simple, parallel. The ferns first described by Lesquereux under the name Aspidium goldianum appear 30 The Cretaceous and Tertiary floras: U. 8. Geol. Survey Terr. Rept., vol. 8, p. 188, 1883. 31 Op. cit. (Tertiary flora), p. 57, pl. 4, fig. 14. 82 This name was preoccupied by the living Aspidium goldianum Hooker, 1824, now Dryopteris goldiana (Hooker) A. Gray, 1848. I have therefore given the fossil orm a new name in honor of its describer. 110 LARAMIE FLORA OF to be very well characterized, being bipinnate, or perhaps it would be better to say bipinnati- fied, with the pinnae alternate, at a low angle of divergence with the main rachis, and lanceo- late in general outline. They are cut nearly to the secondary rachis, with numerous linear- lanceolate, rather obtuse segments. In the type species figured in the “Tertiary flora” (pl. 4, fig. 18) the segments of the pinnae are short, being from 7 to 9 millimeters in length, and have from five to seven pairs of simple nerves, The type of Aspidiwm goldianum Lesquereux (now Dryopteris lesquereuxii) is said to have come from Golden, Colo., and an examination of the specimen (No. 26, U. S. Nat. Mus.) appears to confirm this statement; in any event there is no tangible evidence to the contrary. The species has not been noted in any of the -recent collections from Golden. Occurrence: Laramie formation, Colo. Dryopteris? carbonensis Knowlton, n. sp. Plate XX, figures 3-5. Dryopteris? carbonensis Knowlton [nomen nudum], U. S* Geol. Survey Bull. 696, p. 249, 1919. Golden, Fronds once pinnate (2); pinnae probably lanceolate, deeply pinnatified, the divisions nearly opposite, narrowly deltoid or broadly lanceolate in outline, with obtusely acuminate apex and perfectly entire margins; secondary rachis strong; midnerve of segments thin, practically straight; nerves obscure, apparently remote and simple; fruit unknown. This species is based on the three fragments figured and is apparently quite distinct from anything from the true Laramie heretofore described. Whether it belongs to the genus Dryopteris is not by any means certain, for without fruit that point can not be’ positively ascertained, but from its general resemblance to certain species of this genus I have decided so to refer it. It is, for example, quite like some of the larger pinnae of Dryopteris gol- diana (Hooker), a living species of eastern North America. From its general resemblance to the above- mentioned living species, I have assumed that it had once-pinnate fronds with numerous lanceolate pinnae, but this, of course, is largely conjecture. The divisions of the pinnae are cut a little more than half the distance to the THE DENVER BASIN, midvein. They are slightly scythe-shaped and have rather acute apices. The secondary nerves of the divisions appear to be simple, but the specimens are preserved on a rather coarse grained matrix which is not well suited to preserve the finer nervation, and it is im- possible to say whether they were forked or not. No trace of the fructification is pre- served. A single fragment of this species is found also in the collections from Marshall, Colo.; it is without nervation and is on the same piece of rock with Ficus arenacea. Occurrence: Laramie formation, Mount Car- bon, Morrison, Colo.; sandstone near coal seam, Marshall, Colo.; collected by A. Lakes, 1890. Genus PHANEROPHLEBITES Knowlton, n. gen. Of the general type of the living Phanero- phlebia, but with thick, fleshy midrib, and few free veins. Phanerophlebites pealei Knowlton, n. sp. Plate III, figure 5. Phanerophlebites pealet Knowltoa [nome2 nudum], U.S. Geol. Survey Bull. 696, p. 439, 1919. Outline of whole frond not known but pre- sumably pinnate, pinnae large, strap-shaped, with apparently entire margins; midrib ex- tremely thick and fleshy; nerves numerous, rather fine, usually forking near the midrib and once or twice before reaching the margin, sometimes free but usually anastomosing; fruit not preserved. This form is represented only by the example here figured, and this is more or less frag- mentary, neither base nor apex being retained. It is now about 12 centimeters long but was obviously very much longer when perfect. The width was 4.5 or 5 centimeters. The small portion of the margin preserved shows it to be entire or perhaps slightly undulate. This pinna was evidently of thick substance, as indicated by the very strong midrib and the immersed appearance of the veins. The veins are fine and very close and are more or less conspicuously anastomosed. All the veins fork, and some of them appear to be free, but this feature, owing to the small amount of ma- terial, is difficult to make out. It is with some hesitation that this fragmen- tary specimen is described as establishing a new genus. It is aspidioid in general appear- THE FLORA. ance and seems to approach most closely the living genus Phanerophlebia. This genus em- braces about a dozen rather closely related species extending from the southern border of the United States through Mexico and Central America to Brazil. In some ways the specimen approaches most closely Phanerophlebia nobilis (Schlechtendal and Chamisso) Presl, a native of Mexico, especially in type of nervation. Occurrence: Laramie formation, Lafayette, Colo., dump of Simpson mine, collected by A. C. Peale, for whom the species is named. Asplenium martini Knowlton, n. sp. Plate II, figure 6. Asplenium martini Knowlton [nomen nudum], U. 8. Geol. _ Survey Bull. 696, p. 105, 1919. _ Outline of whole frond unknown but at least thrice-pinnatified, apparently thick or coriaceous in texture; pinnae long-lanceolate, with an exceedingly strong rachis, cut with numerous opposite or subopposite, short, ovate or ovate-oblong, obtuse pinnules; nervation of pinnules strong, consisting of a very strong midvein and 8 or 10 pairs of strong veins, which are once-forked, usually near the base; fruit not seen. This form is so fragmentary as hardly to be worthy of characterization, yet even these small pieces show clearly that it must have been a plant of striking appearance. The fragment is about 8 centimeters in length, and to judge from the very thick rachis it must have been when perfect at least twice this length and was probably even larger. The rachis is fully 2 millimeters thick. Only one pinnule is anywhere near perfect. This is nearly 2 centimeters in length and is about 12 millimeters broad. The pinnules, so far as can be ascertained, were opposite or suboppo- site and cut by a sharp sinus within 4 or 5 millimeters of the rachis. The nervation of the pinnules, as already indicated, is very deeply impressed, showing that. the texture was thick and probably coriaceous. The strong midvein is slightly irregular, and the nerves, also very strong, are once-forked, usually near the midvein. In the absence of fruit it is impossible to be certain of the generic reference, but the form is so distinct, even in the fragments available, that it must constitute a good horizon marker. 111 Among fossil species it is suggestive of Asple- nium magnum Knowlton,® from the Fort Union of the Yellowstone National Park, but it differs in a number of important particulars. It is much larger than Asplenium magnum, being in fact nearly as large as the enlargement of that species shown in figure 8a of the plate above cited. Its pinnules are more deeply cut, and: the nervation is very much stronger, though of the same type. In some respects it is closer to Asplenium coloradense Knowlton,* from the Vermejo formation of the Raton Mesa region, which was at first identified by Hollick* with As- plenium magnum. The form under considera- tion seems to differ from Asplenium coloradense in its larger size, more obtuse pinnules, and much stronger nervation. A series of speci- mens showing the variation in size might bring them together, but for the present they are best kept apart, though obviously closely related. : This species is named in honor of George C. Martin, of the United States Geological Sur- vey, who assisted in making the collection of which it is a part. Occurrence: Laramie formation, dump of Reliance mine, 1? miles northeast of Erie, Colo., collected by F. H. Knowlton and G. C. Martin. Pteris goldmani Knowlton, n. sp. Plate II, figure 3. Pieris goldmani Knowlton [nomen nudum], U. 8S. Geol. Survey Bull. 696, p. 518, 1919. Outline of frond unknown; pinnae lanceolate, margin entire; rachis thin, grooved; nerves numerous, at an angle of 50° or 60°, slightly curved, forking a short distance above the base and again below the margin, often anas- tomosing. Although this is a mere fragment 3 centi- meters long and the same in width, it is so well characterized by the nervation that it seems worthy of full specific rank. It is of the type of what'has been called Pteris subsimplex Lesquereux,** Pteris erosa Lesquereux,*” Pteris undulata Lesquereux, etc., but differs essen- 38 U.S. Geol. Survey Mon. 32, pt. 2, pl. 79, figs. 5-8, 1899. 44 U.S. Geol. Survey Prof. Paper 101, pl. 1, figs. 1, 2, 1918. 3 Hollick, Arthur, Torreya, vol. 2, p. 146, pl. 4, figs. 1, 2, 1902. 86 Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 7, pl. 4, figs. 5-7, 1878. 37 Idem, fig. 8. 112 tially in having the nerves at a more acute angle and regularly twice-forked. The nerves are also frequently anastomosed, especially near the margin. This species is named in honor of Marcus I. Goldman, of the United States Geological Survey, who assisted in making the collection at this locality. Occurrence: Laramie formation, Popes Bluff, west of Pikeview, Colo. (sec. 14, T. 13 S., R. 67 W. ), collected by A. C. Peale and M. L Goldman, 1908. Pteris? sp. Plate II, figure 5. Pteris? sp. Knowlton [nomen], U. S. Geol. Survey Bull. _ 696, p. 513, 1919. The specimen here figured is so small a fragment that were it not for the fact that it is very different from anything heretofore found in the Laramie, it would hardly be worthy of mention. It is the wedge-shaped basal por- tion of what was apparently a large lanceolate frond or pinnule. The midrib was exceedingly thick, and the blade appears also to have been thick or coriaceous. The nerves are very fine, close, parallel, and at a low angle of emergence. It is difficult to ascertain whether the veins fork at the extreme base or are simple, though presumably they are forked just above their point of origin. Occasionally a vein may be observed to fork near the middle, but beyond this little can be made out. This fragment is so small and obscure that comparisons with other forms are hardly war- ranted, though in passing it may be said that the specimen somewhat resembles what Les- quereux described as Gymnogramma gardneri,® especially in the shape of the base and the thick midrib, but it differs strongly in the more numerous finer veins, which do not anastomose. Occurrence: Laramie formation, Marshall, Colo., wooded bluff just south of station, at the highest plant-bearing point in the section, collected by A. C. Peale. Family SCHIZAEACEAE, Anemia elongata (Newberry) Knowlton. Plate II, figure 2. Anemia elongata (Newberry) Knowlton, U. S. Geol. Sur- : vey Bull. 696, p. 74, 1919. © be 38 Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. % rl. 4 | j fig. 2, 1878. LARAMIE FLORA OF THE DENVER BASIN. Sphenopteris (Asplenium) elongatum Newberry, Boston Soc. Nat. Hist. Jour., vol. 7, p. 511, 1863. Anemia subcretacea? (Saporta) Gardner and Ettingshausen, British Eocene flora, vol. 1, Filices, pt. 2, p. 45, pls. 8, 9, 1880.: Knowlton, U. 8. Geol. Survey Bull. 152, p. 34, 1898; Mon. 32, pt. 2, p. 657, 1899; Bull. 163, p. 20, 1900. Anemia perplene Hollick, in Newberry, U. 8. Geol. Sur- vey Mon. 35, p. 3, pl. 15, figs. 1, la, 1898. Gymnogramma haydenti Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 295, 1873; Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 59, pl. 4, figs. 1-3, 1878. Anemia haydenti (Lesquereux) Cockerell, Torreya, vol. 9, p. 142, 1909. My understanding of the status of the Ameri- can material usually referred to Anemia sub- cretacea is set forth at length in my “ Flora of of the Montana formation,” * and I have little or nothing to add to that account. One diffi- culty in the study of ferns of this group is lack of sufficient material, for somehow it happens that although Anemia is fairly well distributed both geologically and geographically, it is rarely found abundant or well preserved. The type specimens of Lesquereux’s Gymnogramma haydenit, for instance, are mere fragments that can give only a partial idea of its size and ap- pearance. The example here figured, although exceptionally well preserved, is the only one present in the collections from Erie. It is al- most entire in the upper portion and sparingly toothed below, but otherwise it is very much like the figures of Gymnogramma haydenii. It is rather more robust than the figures of the English species shown by Gardner and Ettings- hausen would imply, though it approaches that species most closely. I have questioned the reference of the Erie specimen to Anemia sub- cretacea rather than make a new species. If additional material can be procured it may serve to settle the status of this form. Occurrence: Laramie formation, ?Erie, Colo.; Mesaverde, ?Point of Rocks, Wyo.; Puget group, ?Washington. Anemia supercretacea Hollick. Anemia supercretacea Hollick, Torreya, vol. 2, p. 145, pl. 3, figs. 6, 7, 1902. Cockerell, Torreya, vol. 9, p.142, 1909. This species was described by Hollick from material collected in the well-known reddish | sandstone at Florence, Colo., from beds then supposed to be of Laramie age but subse- eat 2. ey *® Knowlton, F. H., U.S. Geol. Survey Bull. 163, pp. 20-22, 1900. THE FLORA. quently determined to belong to the Vermejo formation of the Montana group. It is re- corded from the Laramie at Marshall, Colo., by Cockerell, who says: ' Found first at Marshall by Paul Haworth. Our speci- mens run a little larger than Hollick’s but appear to be otherwise quite identical; the pinnules are entire. The plant may possibly be a variety of Anemia haydenti (Gymnogramma haydenti Lesquereux, 1872), which appears to be distinctly different. from A. subcretacea (Saporta) Gardner and Ettingshausen as originally figured by Saporta. I have not seen the material mentioned by Cockerell, nor has Anemia been noted in any of the collections from Marshall and vicinity that have passed through my hands, though I have no reason to doubt the above detenminu- tion, Occurrence: Vermejo formation, Florence, Colo. (type); Laramie formation, Marshall, Colo., reported by Prof. T. D. A. Cockerell. Anemia sp. Plate II, figure 1. Anemia sp. Knowlton [nomen], U. 8. Geol. Survey Bull. 696, p. 75, 1919. ; In the material from a locality a few miles north of Colorado Springs there is a single frag- ment of the pinnule of an Anemia. The mat- rix on which it is preserved is so coarse grained that only the outline can be made out with cer- tainty. The nervation appears to consist of slender veins at a rather acute angle, but their manner of forking can not be seen. This fragment is very readily comparable with various species of Anemia, especially Anemia subcretacea, but it is so poorly pre- served and so small that it is best left without speculation as to its specific identification. Occurrence: Laramie formation, opposite sand-lime brick works about 4 miles north of Colorado Springs, Colo., collected by A. C. Peale and G. I. Finlay, 1908. Lygodium? compactum Lesquereux. Plate I, figure 1 (type). Lygodium compactum Lesquereux, Am. Jour. Sci., 2d ser., vol. 16, p. 206, 1868; U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1869, p. 196 [reprint, 1875]; idem for 1873, p. 380, 1874; idem for 1876, p. 498, 1878; Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 64, pl. 5, fig. 9, 1878. [Lesque- reux’s figure of the type is here reproduced.] 113 The type and so far as known the only speci- men ever obtained of this species is No. 118 of the fossil-plant collections of the United States National Museum. It is a small fragment preserved on a piece of hard, rather coarse- grained sandstone, and is very obscure. There is much uncertainty as to the proper disposition of this specimen. It is so frag- mentary and its nervation is so poorly pre- served that a satisfactory characterization of it is impossible. There is even some doubt as to whether it is a fern. But in the absence of additional specimens or further information concerning the type, it is retained as left by its author, in the hope that future exploration may clear up its position, though at present it is not of much value. Occurrence: Laramie formation, Marshall mine, Marshall, Colo. .. original collection of F. V. Hayden. Order EQUISETALES. Family EQUISETACEAE. Equisetum perlaevigatum Cockerell. Plate I, figures 8, 9. Equisetum perlaevigatum Cockerell, West Am. Scientist, vol. 6, p. 154, 1889. Equisetum laevigatum Lesquereux, U. 8. Geol. and Ceog. Survey Terr. Ann. Rept. for 1873, p. 395, 1874; idem for 1876, p. 498, 1878; Tertiary flora: U. S. Geol. Survey Terr. Rept. vol. 7, p. 68, pl. 6, figs. 6, 7, 1878. [Lesquereux’s original figures are here reproduced.] [Homonym, Al. Braun, 1867.] This so-called species is a very unsatisfactory one indeed. The material upon which it is founded is preserved in the United States National Museum (Nos. 42, 43) and represents, so far as known, all that has ever been found. The larger specimen (original of Lesquereux’s fig. 7), from Sand Creek, Colo., is very obscure and has more the appearance of a piece of dicotyledonous bark, or the impression of a stem. Its surface is wrinkled irregularly rather than striately, and the so-called tuber- cles can hardly be made out. As a factor in the distribution of the species this specimen can safely be ignored. The smaller specimen (original of Lesque- reux’s fig. 6), from the hard white sandstone at Golden, Colo., is without ‘doubt a portion of the underground stem of an Eguisetum, but it 114 could probably not be distinguished from cer- tain other described species, and the advisa- bility of retaining it is open to question. It is permitted to stand simply for the purpose of showing that the horsetails were present in these beds, though it may be but poorly char- acterized. Occurrence: Laramie formation, Golden, Colo., original Museum collections. Phylum SPERMATOPHYTA. Class GYMNOSPERMAE. Order CONIFERALES. Family ARAUCARIACEAE. Dammara sp. Plate IJ, figure 4. Dammara sp. Knowlton [nomen], U.S. Geol. Survey Bull. 696, p. 228, 1919. In the collection from the wooded bluff south of Marshall, Colo., there is a single fragmentary scale that appears to be a Dammara. It is about 13 millimeters long and some 8 milli- meters wide at the broadest point; it is strongly ribbed. The apical portion is broken away, so it is impossible to observe the spine of the scale, if there was one. The specimen is so fragmentary that it is hardly worth while to institute any comparisons with published forms. It was found in the association with Rhamnus salictfolius, Rhamnus goldianus?, and the fragment of a fern described as Pteris? sp. Occurrence: Laramie formation, Marshall, Colo., wooded bluff just south of station, high- est point in section, collected by A. C. Peale. Family TAXODIACEAE. Sequoia acuminata? Lesquereux. Plate II, figures 7, 8. Sequoia acuminata Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, p. 310, 1875; idem for 1876, p. 500, 1878; idem, Bull., vol. 1, No. 5, 2d ser., p. 384, 1876; Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 80, pl. 7, figs. 15-16a, 1878. The type specimens of this species are sup- posed to be preserved in the United States National Museum (No. 62), but they can not now be found. So far as can be made out from the figures it seems to be very close to LARAMIE FLORA OF THE DENVER BASIN. Sequoia. longifolia Lesquereux, a fact which Lesquereux recognized, as ‘he says: ~ This species differs from the former by the proportion- ally narrower leaves, with a very distinct middle nerve, and smooth surfaces; also by the stem, which is striate when decorticated. * * * The average size of the leaves is about the same in both forms, the leaves varying _ from 3 to 6 centimeters long and from 2 to 5 millimeters broad. In the collection from Cowan station there is a single fragment that may belong to this species, but it is so fragmentary that the essential characters can not be made out with certainty. The two examples figured, though frag- mentary and not well preserved, appear to agree in all essential features with the speci- mens figured by Lesquereux. Occurrence: Post-Laramie, Black Buttes, Wyo. (types). Laramie formation,? Cowan station, 10 miles south of Denver, Colo., col- lected by F. H. Knowlton; cut on Moffat rail- road (Denver & Salt Lake) near Leyden Gulch, Colo., collected by A. C. Peale. Dawson arkose, Templeton Gap, 4 miles northeast of Colorado Springs, Colo., collected by A. C. Peale, 1908. Sequoia reichenbachi (Geinitz) Heer. Plate XX, figures 1, 2. Araucarites reichenbachi Geinitz, Charakteristik der Schicht- en und Petrefacten des sichsisch-béhmischen Krei- degebirges, pt. 3, p. 98, pl. 24, fig. 4, 1842. Sequoia reichenbachi (Geinitz) Heer, Flora fossilis arctica, vol. 1, p. 83, pl. 48, figs. 1d, 2b, 5a, 1868. Lesquereux, U. 8. Geol. Survey Terr. Rept., vol. 6, p. 51, pl. 1, figs. 10-10b, 1874; U. 8. Geol. Survey Mon. 17, p. 35, pl. 2, fig. 4, 1892. Hollick, New York Acad. Sci. Trans., vol. 12, p. 30, pl. 1, fig. 18, 1892. Fontaine, U. 8. Geol. Survey Mon. 15, p. 243, pl. 118, figs. 1, 4; pl. 119, figs. 1-5; pl. 120, figs. 7, 8; pl. 122, fig. 2; pl. 167, fig. 5, 1889. : Dawson, Roy. Soc. Canada Trans., vol. 3, p. 21, 1882. Newberry, U. 8. Geol. Survey Mon. 26, p. 49, pl. 9, fig. 19, 1896. Knowlton, U. 8. Geol. Survey Mon. 32, pt. 2, p. 657, 1898. , In the collection from Coal Creek, Boulder County, Colo., there is a single specimen which I am unable to separate from many of the fig- ures referred to Sequoia reichenbachi, and I have so regarded it. As may be noted in the figure (Pl. XX, fig. 1), it is a fairly well pre- served specimen with a large main branch and several smaller branchlets bearing rather closely appressed, sharp-pointed leaves. It is, for ex- ample, hardly to be distinguished from figures of this species given by Velenovsky “ from the Cretaceous of Bohemia. I also find in the old United States National Museum collections a single specimen, recorded under No. 865, which was collected at Coal Creek by George Hadden. It was not figured by Lesquereux and repre-. sents the impression of a fragment from a large branch. It is indistinguishable from figure 23 of Plate VII in Lesquereux’s “Tertiary flora.” “ Among the specimens collected by Arthur Lakes at Mount Carbon, Morrison, Colo., from the sandstone near the coal seam, are a number of rather poorly preserved but evidently large branches of a conifer that I am unable to distin- guish from this species. By taking an impres- sion in clay the original form of the branches is restored in a fairly satisfactory manner. The leaves are seen to be rather long, sharp pointed, and spreading, but with incurved tips. The small collection made on Crow Creek, Colo., contains three rather poorly preserved specimens of conifers that appear to be refer- able to this species. They are long, slender twigs covered with short, appressed scalelike leaves and apparently additional more slender leaves. They are not well enough preserved to warrant a positive reference to this or any other species. ‘Occurrence: Laramie formation, Coal Creek, Boulder County, Colo., collected by N. L. Britton about 1884; Mount Carbon, Morrison Colo., collected by A. Lakes in 1890; Crow Creek about 25 miles northeast of Greeley, Colo., collected by F. H. Knowlton and T. W. Stanton, 1896. The last is questionable. Sequoia longifolia Lesquereux. Plate III, figure 3; Plate IV, figure 2. Sequoia longifolia Lesquereux, U.S. Geol. and Geog. Sur- vey Terr. Ann. Rept. for 1874, p. 298, 1876; Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 79, pl. 61, figs. 28, 29 [not pl. 7, figs. 14, 14a, which= Sequoia magnifolia Knowlton]. Geinitzia longifolia (Lesquereux) Knowlton, U. 8. Geol. Survey Bull. 63, p. 28, 1900. Cunninghamites? sp.? Knowlton, U. 8. Geol. Survey Bull. 163, p. 29, pl. 5, fig. 3, 1900. 40 Velenovsky, Josef, Die Gymnospermen der pbdhmischen Kreide- formation, pl. 9, figs. 12, 14, etc., 1885. 4. U. 8. Geol. Survey Terr. Rept., vol. 7, 1878. THE FLORA. 115 There appears to be some confusion regarding Lesquereux’s Sequoia longifolia. So far as can be made out, Lesquereux had specimens of a long-leaved conifer from Black Buttes, Wyo., to which it is inferred he gave the manuscript name ‘Sequoia longifolia.”’ Before this species was published, however, specimens thought to represent the same species were obtained from Point of Rocks, Wyo., and the name was first published in the Hayden Annual Report for 1874 (1876), page 298, under the designation “Sequoia longifolia Lesq., MSS.” In explana- tion he adds: “This species was already de- scribed from Black Buttes specimens.”’ I can not find that it was ever published in connec- tion with the Black Buttes specimens, and it seems that when Lesquereux actually came to publishing a report on the Black Buttes mate- rial he changed the name of the long-leaved conifer common at that place to Sequoia acumi- nata.2 It is certain that he nowhere definitely recorded Sequoia longifolia as coming from Black Buttes, nor has it since been found there. If the above interpretation is correct, as it is believed to be, it establishes Point of Rocks, Wyo., as the type locality for Sequoia longi- folia and excludes the species from Black Buttes. The type specimens are the originals of figures 28 and 29 of Plate LXI of the ‘Ter- tiary flora” and are Nos. 73 and 74, respec- tively, of the United States National Museum collections. This leaves the specimen figured under this name in Plate VII, figures 14, 14a, of the ‘Tertiary flora”’ still to be accounted for. It is said “ to have come from the “ Haley coal mine, 10 miles northeast of Greeley, Colo. (A. C. Peale)”; it is No. 61 of the United States National Museum collections. I was informed by Dr. Peale that this statement was in error, as he did not collect it and was never at this locality. Inasmuch as Lesquereux pointed out certain marked differences between the Point of Rocks and Greeley specimens and added, ‘It may be, therefore, that these speci- mens represent two different species,’ and in further consideration of the uncertainty regard- ing the so-called Greeley specimen, it is appar- ently justifiable to consider only the Point of 2U.S. Geol. Survey Terr. Bull., vol. 1, No. 5, 2d ser., p. 384, 1876; U.S. Geol. Survey Terr. Rept., vol. 7, p. 80, 1878. 48 Lesquereux, Leo, op. cit., p. 80. 116 LARAMIE FLORA OF Rocks specimens in the present comparisons and discussions. Additional specimens from Point of Rocks were procured by L. F. Ward in 1883,*4 but none have been found in or about the supposed Greeley locality. In the light of material recently studied it now seems probable that the specimen from the North Fork of Dutton Creek, Laramie Plains, Wyo., which I figured and described under the name Cunninghamites? sp., * should be referred to the present form. Although the full characters can not be made out, owing to poor preservation, the general appearance is the same as in many specimens that un- doubtedly belong to Sequoia longifolia. It was suggested by Schenk “* a number of years ago that Lesquereux’s Sequoia longifolia should be referred to the genus Geinitzia, and as cones had not been found at that time, I adopted the suggestion and in my “Flora of the Montana formation’’*” transferred it to this genus. Although cones have not been found in connection with these specimens, they have been found attached to specimens that are now described under the name Sequoia magnifolia Knowlton,* and as these two forms are undoubtedly congeneric it is best to refer them all to Sequova. The material from Marshall, Colo., includes several specimens of coniferous branches that are not to be distinguished from Sequoia longifolia as described and figured by Les- quereux from Point of Rocks; Wyo. One of the best of these branches is here figured. It is a thick branch 1 centimeter in diameter and about 15 centimeters long. The scars on the branch and the insertion of the long, slender, acuminate leaves are the same as shown in figure 29 of Plate LXI in the “Tertiary flora.” The manner in which the leaves are matted together is also the same, and there can be no reasonable doubt of their identity with Les- quereux’s species. A single poorly preserved branchlet (shown in Pl. IV, fig. 2) from Cowan station, south of Denver, appears to belong to this species. 4“ Knowlton, F. H., U. 8. Geol. Survey Bull. 163, p. 28, 1900. 4 Idem, p. 29, pl. 5, fig. 3. 46 Schenk, A., in Zittel, K. A., Handbuch der Palaeontologie, Abt. 2, pp. 301, 302, 1880. 47 Knowlton, F. H., U. 8. Geol. Survey Bull. 163, p. 28, 1900. 4 Knowlton, F. H., The flora of the Fox Hills sandstone: U.S. Geol. Survey Prof. Paper 98, p. 88, pl. 15, figs. 1-3, 1916. THE DENVER BASIN. Occurrence: Mesaverde formation, Point of Rocks, Wyo. (type locality). Laramie forma- tion, Marshall, Colo., railroad cut between old and new stations, collected by A. C. Peale, 1908; Cowan station, 10 miles south of Denver, Colo., collected by F. H. Knowlton, 1908. Order CYCADALES. Family CYCADACEAE. Cycadeoidea mirabilis (Lesquereux) Ward. Cycadeoidea mirabilis (Lesquereux) Ward, Biol. Soc. Wash- ington Proc., vol. 11, p. 86, 1894. Zamiostrobus mirabilis Lesquereux, U. 8. Geol. and Geog. Survey Terr. Bull., vol. 1, No. 5, 2d ser., p. 383, 1876; ddem, Ann. Rept. for 1874, p. 309, 1876; Tertiary flora: U.S. Geol. Survey Terr. Rept., vol. 7, p. 70, pl. 63, figs. 1-1d, 1878. Nelumbium James, Science, vol. 3, p. 434, 1884. Clathropodium mirabile (Lesquereux) Ward, Science, vol. 3, p. 532, 1884. Cycadeoidea zamiostrobus Solms, Real. accad. sci. Ist. Bologna Mem., 5th ser., vol. 2, p. 210, 1892. . It is extremely doubtful whether this species should properly be included in this work, but I have given it the benefit of the doubt. It was found by F. V. Hayden lying on the sur- face of the ground near Golden, Colo., within the Laramie area, but it probably belonged to a more ancient formation, from which it had been transported. The microscopic appear- ance of this interesting species was well de- scribed and fairly well figured by Lesquereux, and the internal structure has been admirably worked out by Count Solms, to whom the cutting and study of the specimen was sub- mitted. It is mentioned further by G. R. Wieland in his work on American fossil cycads.* Occurrence: Laramie formation (2), near Golden, Colo. Class ANGIOSPERMAE. Subclass MONOCOTYLEDONAE. Order GRAMINALES, Family CYPERACEAE? Cyperacites? hillsii Knowlton, n. sp. Plate XX, figure 6. Cyperacites? hillsiti Knowlton [nomen nudum], U. S. Geol. Survey Bull. 696, p. 222, 1919. Leaves flat, without keel; nerves numerous, parallel, 5 millimeters apart, with a single more Carnegie Inst. Washington Pub. 34, vol. 2, p. 109, 1.1, figs. 1, 2, 1918. THE FLORA. delicate intermediate nerve between the prin- cipal ones. The material upon which this form is based is in reality hardly sufficient for the proper characterization of a new species, but as it appears to differ from all other Laramie species already described it must receive a name. It is based on fragments of leaves 7 or 8 centi- meters long and from 1 to 1.5 centimeters wide. They are marked by numerous parallel veins about 5 millimeters apart, with slender Intermediate veins, one between every two of the stronger ones. It is named in honor of Mr. R. C. Hills, of Denver, Colo. Occurrence: Laramie formation, Erie and Coal Creek, Colo. Cyperacites? tessellatus Knowlton, n. sp. Plate III, figures 1, 2.. Cyperacites? tessellatus Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 222, 1919. In the material from Popes Bluff, the locality earlier known as the Healey coal mine, there are several fragments of a large monocoty- ledonous leaf that is very strongly marked. Neither the length nor the width can be ascer- tained, though there are fragments 8 centi- meters long and 5 or 6 centimeters wide. It is provided with strong, deeply impressed longi- tudinal veins which are a little less than 1 millimeter apart and without intermediate veins. It is, however, also provided with cross veins, which. are nearly as deeply im- pressed as the others and cut the space between the veins into very regular rectangular areas about 1 millimeter long. This was evidently a thick, firm leaf, as the veins and cross veins are so deeply impressed. The proper generic reference for this form is uncertain. Superficially it resembles Zingi- berites dubius Lesquereux,” from the. Denver formation, but it is excluded at once by the fact that the latter species has six or seven very thin veins between the strong veins. It also resembles certain leaves that have been re- ferred to Typha, such as Typha latissima Heer,” but it is twice the width of even the largest leaves of that species and has three or four intermediate veins between the larger ones. The cross veins in Typha are very much like «0 Lesquereux, Leo, U. 8. Geol. Survey Terr. Rept., vol. 7, p. 95, pl. 16, fig. 1, 1878. £ 8 Heer, Oswald, Flora tertiaria Helvetiae, vol. 1, pls. 43, 44, 1855. 117 those in the present specimens, but none of the nervation is deeply impressed. Occurrence: Laramie formation, Popes Bluff, west of Pikeview, Colo. (sec. 14, T. 13 8., R. 67 W.), collected by A. C. Peale and M. I. Gold- man, 1908. Cyperacites? sp. Plate IV, figure 1. Cyperacites? sp. Knowlton [nomen], U. 8. Geol. Survey ‘ Bull. 696, p. 223, 1919. The collections from Leyden Gulch contain a number of specimens that are somewhat diffi- cult of interpretation, though obviously they are of monocotyledonous type. They appear to represent the stems and leaves of some plant resembling a sedge or possibly a grass. They are from 8 to 10 millimeters wide and nearly 1 millimeter in thickness as now compressed ; what appear to be leaves of the same plant. are 1.5 centimeters wide. They are provided with numerous very fine, close, parallel nerves, about 8 or 10 to each millimeter. There is a little evidence to show that some of the nerves are slightly heavier than the others, but the difference is not marked. There is also some evidence of the presence of cross veins, but this is very obscure. This form is of no particular importance bio- logically and is described simply for the pur- pose of showing that certain plants of this general type were present at this time. Occurrence: Laramie formation, Leyden Gulch, 64 miles north of Golden, Colo., collected by A. C. Peale, 1908. Family GRAMINEAE. Phragmites laramianus Cockerell. Phragmites laramianus Cockerell, Torreya, vol. 9, p. 141, 1909. Phragmites oeningensis Al. Braun. - Lesquereux, Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 88, pl. 8, figs. 1, 2, 1878. The specimens figured by Lesquereux in the “Tertiary flora” under the name Phragmites oeningensis are preserved in the collections of the United States National Museum (Nos. 93, 94). They came from Golden, Colo., the matrix on which they occur being the hard white sandstone characteristic of the Laramie at that locality. These specimens are before me and appear to have been fairly well figured and described. They are mere fragments, 118 LARAMIE FLORA OF however, and fail to show any very marked characters. The specimen shown in Lesque- reux’s figure 2 is a ribbed, intranodal portion of a stem about 4.5 centimeters long and 2 centi- meters broad; it does not exhibit any of the characters of the node or joint. The small fragment just below it is without markings except for the deep scar at one end. It is wholly unconnected with the other fragments, and there is no certainty that they were organ- ically in union. The specimen of Lesquereux’s figure 1 appears to represent roots or under- ground portions with scattered scars which may indicate the origin of the rootlets, but this point is obscure. Its connection with the ribbed portion of the stem is purely conjec- tural. » ‘The material from Hoyt’s mine, near Golden, contains a single fragment of a ribbed stem like that shown in Lesquereux’s figure 2, but it is even shorter than the one figured and shows none of the nodal characters. A small stem evidently referable to this form was con- tained in the material from Mount Carbon, near Morrison, but it adds nothing to our knowledge of this plant. The question has arisen as to the propriety of identifying these American plants with the European Phragmites oeningensis. A com- parison with the figures of the Old World form, such as those of specimens from the Swiss Miocene given by Heer,” discloses a strong. generic resemblance, and possibly there would also be specific resemblance if the essential characters of our specimens could be fully made out. As already pointed out, no speci- men appears to have been found which shows the full node with its markings. The strong ribs on the European specimens have usually about six intermediate, much slenderer veins between them. The Golden specimens are preserved on a rather coarse grained rock which obscures the intermediate veins, but so far as can be made out there are not more than three between the strong ribs. In view of the strati- graphic difference between these American and the European specimens, it seems best not to identify the Laramie forms with Phragmites oeningensis. ‘ Cockerell in 1909 separated the American specimens, under the name Phragmites lara- mianus. 52 Heer, Oswald, Flora tertiaria Helvetiae, vol. 1, pl. 24, 1855. THE DENVER BASIN. Occurrence: Laramie formation, Golden, Colo. [original Lesquereux specimens figured in the “Tertiary flora” as P. oeningensis]; Hoyt’s coal mine, 1 mile south of Golden, Colo., col- lected by Arthur Lakes, 1890; Mount Carbon, Morrison, Colo., sandstone near coal seam, col- lected by Arthur Lakes, 1890. Order LILIALES. Family SMILACEAE? Smilax? inquirenda Knowlton, n. sp. Plate IV, figure 5. Smilax? inquirenda Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 602, 1919. Leaf of medium size, apparently firm in tex- ture, ovate, abruptly rounded to the slightly heart-shaped base; apex destroyed; nervation palmate, five-ribbed from the base of the blade, midrib and next pair of ribs about equally strong, the ribs passing up apparently to the apex of the leaf; lower pair of ribs slenderer, much curved upward, ending near or below the middle of the leaf, secondary branches few, thin, camptodrome. This leaf was probably about 7 centimeters Jong when perfect and is 4.5 centimeters wide. It may be known by its ovate-elliptical outline, rounded, slightly heart-shaped base, and five ribs, the three inner ones being of nearly equal strength; these ribs pass up nearly or probably quite to the apex of the blade. The secondary and finer nervation is obscure. Smilax grandifolia Unger, or S. carbonensis, as it has recently been named by Cockerell,® was reported by Lesquereux™ from the Laramie at the Franceville mines, near Colorado Springs, but the material on which this determination was based is not now available, nor is the species contained in the recent collections from that locality. The present leaf differs from S. grandifolia in being narrower, less heart- shaped at the base, and five instead of seven ribbed; in fact, it is not certain that this leaf is properly referable‘to the genus Smilax. Occurrence: Laramie formation, Popes Bluff, west of Pikeview, Colo. (sec. 14, T. 13,S., R. 67 W.). 7 58 Cockerell, T. D. A., Two new plants from the Tertiary of the West: Torreya, vol. 14, p. 135, 1914. 54 Lesquereux, Leo, U. S. Geol. and Geog. Survey Terr. Ann. Rept, for 1878, p. 393, 1875. THE FLORA. Order ARECALES. Family PALMACEAE. Sabal montana Knowlton. Plate ITI, figure 4. Sabal montana Knowlton, U.S. Geol. Survey Prof. Paper 101, p. 253, pl. 32, fig. 3, 1918. Sabalites grayanus (Lesquereux) Lesquereux, Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 112, pl. 12, fig. 1 [not pl. 12, fig. 2], 1878. Knowlton, U. 8. Geol. Survey Bull. 163, p. 32, pl. 6, fig. 5, 1900. Leaves of large size, perhaps the largest of all species found in the Rocky Mountain area, palmate, with approximately 90 rays or folds; petiole unarmed, apparently rounded on both surfaces, 4 to 6 centimeters broad, prolonged at apex with a relatively short triangular point that is usually not more than 10.or 15 centime- ters long, and often only 8 centimeters. Notwithstanding the fact that this species has been reported—mainly under the name of Sabal or Sabalites grayanus—from a number of localities, it is still imperfectly known. It is so large that usually specimens that are any- where near perfect can not be obtained. The type locality for Sabalites grayanus is the Wilcox group of the Gulf region, where, ac- cording to the recent. work of E. W. Berry, it is not uncommon in several localities. It is a relatively small-leaved species with a rather slender petiole and fewer rays than in S. montana. What is believed to be the same species has been found in the Raton formation of southeastern Colorado and northern New Mexico. Sabal montana was based on material from the Vermejo formation of the Raton Mesa, re- gion of Colorado and New Mexico, together with the very large leaf from the Mesaverde for- mation at Point of Rocks, Wyo., described by ‘Lesquereux * under the name Sabalites gray- anus. The original of this specimen is No. 108 of the fossil-plant collections in the United States National Museum, and I obtained an additional example at Point of Rocks in 1896. The other specimen figured in the “Tertiary flora” (PI. XII, fig. 2) is No. 109 of the United States National Museum collections. It is said 55 Lesquereux, Leo, The Tertiary flora: U, S, Geol. Survey Terr. Rept., vol. 7, pl. 12, fig. 1, 187% 119 to have come from the “hard sandstone be- tween coal banks” at Golden, Colo., but an examination of the matrix shows that it is not from the sandstone but from the andesitic ma- terial and hence must have come from the Denver formation. It is the one specimen on which the presence of this species in the Denve1 depends, for no leaves have been found that. could with certainty be referred to that forma- tion. That this specimen is the petiole of a palm is clear, but beyond that it is impossible to go. It might as well belong to any of the other large palms, and as a factor in revealing the distribution of this species it must be dis- missed. Occurrence: Laramie formation, dump of. Reliance mine, 13? miles northeast of Erie, Colo., collected by F. H. Knowlton; Hoyt’s coal mine, 1 mile south of Golden, Colo., collected by Arthur Lakes, 1890. Order JUGLANDALES. Family JUGLANDACEAE. Juglans leydenianus Knowlton, n. sp. Plate V, figure 1. Juglans leydenianus Knowlton [nomen nudum], U.'S. Geol. Survey Bull. 696, p. 334, 1919. Leaflet evidently membranaceous, apparently ovate-lanceolate, strongly unequal sided; mar- gin perfectly entire; midrib fairly strong, straight; secondaries rather remote, alternate, thin, those on the narrow-side of the leaflet at an angle of approximately 40°, then much curved upward and camptodrome, those on the brodd side of the leaflet emerging nearly at a right angle, then curved upward and running for a considerable distance just inside the mar- gin; nervilles few, thin, oblique to the seconda- ries. The fragment figured, which is apparently near the middle of the leaflet, is all that has been found of this form, and but for the fact that the nervation is so strongly marked, it would hardly be worthy of treatment. The length can not be made out, though it prob- ably exceeded 12 centimeters; the width is nearly 7 centimeters. Occurrence: Laramie formation, Leyden Gulch, 64 miles north of Golden, Colo., col- lected by F. H. Knowlton, 1908. 120 LARAMIE FLORA OF Juglans newberryi Knowlton, n. sp. Plate XX, figures 8-10. Juglans newberryt Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 335, 1919. Leaves or leaflets large, about 15 centimeters long and 4.5 or 5 centimeters wide, with entire margins; blade long, narrow, wedge- shaped and strongly inequilateral at base, rather long-acuminate at apex; midrib thick, strong; secondaries alternate, numerous (about 20 pairs), at an open angle, camptodrome, arch- ing and joining just inside the borders, some- times festooned outside the arches; interme- diate secondaries numerous, often extending nearly to the margin; nervilles strong, mainly percurrent and oblique to the secondaries; reticulation obsolete. This fine species is represented by four specimens, none of which, however, is pre- served entire. Two of them have the bases preserved, one the apex, and the other repre- sents a segment near the middle of the blade. They are rather long, narrow leaflets, strik- ingly inequilateral at the base and acuminate at the apex. This species calls to mind a number of fossil forms, yet when carefully compared with them it is found to differ from all. It has, for ex- ample, much the shape and size of Juglans denticulata Heer, or J. crossii Knowlton, as it is now called,** which differs in having numer- ous sharp teeth. It also suggests certain of the narrower leaflets of J. rugosa Lesquereux,” which differs in general in being more or less heart-shaped at the base and in having fewer secondaries. . Juglans acuminata Al. Braun,® of the Swiss Miocene, which, by the way, it is almost im- possible to distinguish from J. rugosa, has much the same nervation and size as J. new- berryi but differs in shape. Juglans califor- nica Lesquereux,® from the auriferous gravels of California, is not greatly unlike the form under discussion, differing in being obtuse at the apex and less unequal-sided at the base. I have named this species in honor of the late Dr. J. S. Newberry; who did so much to develop the paleobotany of the Rocky Moun- tain region. 56 U.S. Geol. Survey Bull. 152, p. 122, 1898. 51 U.S. Geol. Survey Terr. Rept., vol. 7, p. 286, pl. 55, figs. 1-9, 1878. 58 Flora tertiaria Helvetiae, vol. 3, pl. 128, figs. 1-10. 9 Harvard Coll. Mus. Comp. Zoology Mem., vol. 6, pl. 9, fig. 14, 1878. THE DENVER BASIN. Occurrence: Laramie formation, Erie, Colo., collected by N. L. Britton about 1880. ° Juglans laramiensis Knowlton, n. sp. Plate XX, figure 12. Juglans laramiensis Knowlton [nomen nudum], U. §.. Geol. Survey Bull. €96, p. 334, 1919. Leaflets coriaceous, long and narrowly ovate- lanceolate, often slightly unequal-sided at the base, rather gradually narrowed from the widest point, which is about one-fourth the length of the blade, to the base and upward to the long, narrow acuminate apex; margin entire; nervation strongly and plainly marked, consisting of a rather strong, straight midrib and some 9 or 10 pairs of alternate or sub- opposite secondaries which arise at an angle, curve considerably upward, and disappear close to the margin or, especially in the upper part, join the secondary next above; nervilles numerous, strong, both percurrent and broken, inclining to be at right angles to the midrib on one side of the blade and to the secondaries on the other side; finer nervation not retained. This strongly marked species is represented by several specimens, one of the best of which is figured. They are lanceolate or very narrowly ovate-lanceolate, with an obtusely wedge-shaped base and a long, gradually narrowed, sharp-pointed apex. The larger of these two examples is 9.5 centimeters in length and about 3 centimeters in width; the smaller is about 8 centimeters in length and 2.25 centimeters in width. The petiole is not preserved in either. This species is very suggestive of Juglans schimperi Lesquereux,® from the Green River formation at Green River, Wyo. It is of practically the same shape and size but differs in having only 9 or 10 instead of some 18 pairs of secondaries, which are at a more acute angle and rather more arched upward, while the nervilles are stronger, more commonly per- current, and at right angles to the midrib on one side. In his treatment of Juglans schimperi in the “Tertiary flora” Lesquereux states * that the original of his Plate LVI, figure 9, came from Golden, Colo. This particular specimen is fortunately preserved in the United States 6 The Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, pl. 56, figs. 5-10, 1878. 1 Idem, p. 288. THE FLORA. National Museum (No. 468), and in the cata- logue of fossil plants it is recorded in Les- quereux’s handwriting as having come from Green River, Wyo. The matrix is not that of Golden but agrees perfectly with the abun- dant material found above the fish beds at Green River, and there is consequently no reason for supposing that this species has ever been found in the Denver beds at Golden. Occurrence: Laramie formation, Coal Creek, Boulder County, Colo., collected by N. L. Britton about 1880. Juglans leconteana Lesquereux. Plate VIII, figures 1-3 [types]. Juglans leconteana Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1870, p. 382, 1872; idem for 1876, p. 517, 1878; U. S. Geol. Survey Terr. Rept., vol. 7, p. 285, pl. 54, figs. 10-13. 1878 [figs. 10-12 here reproduced]. Friederich, Beitriige zur Kentniss der Tertiarflora von Sachsen, p. 150, pl.'19, fiz. 7, 1883 This species is in much confusion. Three of the specimens figured in the “Tertiary flora” (figs. 10-12) are not now and have apparently never been in the collections of the United States National Museum. They came, accord- ing to Lesquereux, from the Marshall coal mine, in Boulder County, Colo., and are. prob- ably lost. The original of Lesquereux’s figure 13 is the only one in the United States National Museum (No. 453). It is stated in the ‘‘Tertiary flora” to have come from Evans- ton, Wyo., but in the Museum catalogue it is recorded from Black Buttes, Wyo., in Les- quereux’s handwriting. This last statement is probably correct, for the fossil is preserved in a fragment of the “red baked shale’ so characteristic of the upper beds at this place. In the annual report of the Hayden Survey for 1870, page 382, this species is recorded in a list of species found at Raton Pass, N. Mex., but the specimen or specimens upon which this statement is based has never been in the United States National Museum, and the refer- ence may safely be dismissed as an error. Lesquereux has also reported this species from Cherry Creek, Wasco County, Oreg., but there was only a single example, which I ex- cluded from my flora of these beds ® on the ground that it was so poorly preserved as to be impossible of determination. 62U, 8. Geol. Survey Bull. 204, p. 88, 1902. 121 Friederich has identified this species with a leaf from the lower Oligocene of Bornstedt, in Saxony, remarking at the same time that he was unable to draw any line between Lesquereux’s Juglans rugosa, J. rhamnoides, and J. leconteana. He also adds that they might better be referred to Diospyros, a view which can hardly be accepted, for J. rugosa at least. Lesquereux himself acknowl- edges that it is hardly possible to distinguish this species from J. rugosa, yet he says: It differs by comparatively shorter, broader leaves, which are first rounded, then abruptly curved or narrowed to the short petiole; by the lateral nerves at a more acute angle of divergence (40°), passing nearly straight toward the borders, with thin simple bows nearer to them. Although the differences are not great and might possibly break down with a larger series of specimens for comparison, I have decided to maintain this species as left by its author, especially as the types are nearly all lost, and no additional material is forth- coming. Occurrence: Laramie formation, Marshall mine, Marshall, Boulder County, Colo. Post- Laramie (in my opinion), Black Buttes, Wyo. Evanston formation?, ?Evanston, Wyo. Juglans praerugosa Knowlton, n. sp. Plate V, figure 2; Plate X XI, figure 5. _Juglans praerugosa Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 396, 1916. Juglans rugosa Lesquereux, Am. Jour. Sci., 2d ser. vol. 45, 1868; U. S. Geol. Survey Terr. Third Ann, Rept., p. 96, 1869 [reprint, p. 196, 1873]. Leaflets evidently rather thin in texture, ovate or ovate-elliptical, abruptly rounded to the truncate base (apex destroyed); margin entire; midrib slender, straight; secondaries apparently six or seven pairs, alternate, at a low angle, camptodrome. The specimens upon which this ion is of necessity founded are fragmentary, and com- plete characterization is difficult. It appears ‘to be broadly ovate or perhaps elliptical-ovate. It may also possibly be slightly unequal-sided. The length was apparently about 9 or 10 centi- meters, and the width between 4 and 4.5 centimeters. Juglans rugosa Lesquereux was named in 1868 from material obtained from the Marshall mine, Marshall, Colo., but it was neither described nor figured at that time. The only 122 note of explanation then given is as follows: “Very nearly related to J. acuminata Al. Braun, a species extensively distributed in the Euro- pean Miocene.” This noté was copied without change by Hayden “ in 1869, and the species was alluded to in several other Hayden reports, but not until 1878 ® was it really described and figured. Now, another complication is intro- duced with the describing and figuring of this species. The original locality of Marshall for Juglans rugosa is nowhere mentioned in the “Tertiary flora,” and, so far as known, none of the original specimens are extant. The diagnosis and figures in the “Tertiary flora”’ are based in the main on material from Evans- ton, Wyo., obtained “above the coal.” Of the 13 figured specimens of Juglans rugosa, 11 are now in the collection of the United States National Museum, the missing ones being the originals of Lesquereux’s Plate LIV, figure 5, and Plate LVI, figure 1. Both these specimens are said to have come from Golden, Colo., though whether from Laramie or Denver beds can not be ascertained. In order that there may be less trouble in future in identifying these type specimens, the following list is given of their illustrations in the “Tertiary flora’ and the corresponding numbers in the United States National Museum catalogue: Catalogue No. Plate LIV, figure 14.................. 454 Plate LV, figure 1.............----.--. 851 AGQUIC Binns erates s aueeeweey ss 455 PiGUIE’ 3 e2. ci secwiesecee sees 455a figtive 4... scion caecnseceee 456 figure 5..............2------ 457 figure: Gi nears o: sigiteaesensts 458 figure: 75. 2c202ssiisenaeeaes 460 fiptire: 9 cover eceice cases 459 Plate LVI, figure 2.........-....----- 463 Of these specimens Nos. 455, 455a, 457, 458, 459, 461, and 851 are from Evanston, Wyo., and are so recorded in the Museum catalogue. No. 460 is recorded as being from Golden, Célo., but attached to the specimen is a small, obscure original label which states that it also is from Evanston, and as it agrees perfectly with the matrix of the other specimens this label is probably correct. No. 456 is said to be from Point of Rocks, Wyo., but the matrix is 63 Am. Jour. Sci., 2d ser., vol. 45, p. 206, 1868. 6 U. S. Geol. Survey Terr. Third Ann. Rept. (reprint, 1873], p. 193. 65 Lesquereux, Leo, The Tertiary flora: U.8. Geol. Survey Terr. Rept., vol. 7, p. 286, pl. 54, figs. 5, 14; pl. 55, figs. 1-9; pl. 55, figs. 1, 2, 1878. LARAMIE FLORA OF THE DENVER BASIN. also like that of the Evanston specimens and unlike that ordinarily found at Point of Rocks, though we are confronted by the fact that it bears an original label recording it from the latter locality. This species was not recog- nized in my ‘‘Flora of the Montana formation,” * and it is probably safe to exclude it from Point of Rocks. It has, however, been found subsequently at many localities, such as Golden, Colo., in beds of Denver age; Carbon, Wyo., in the “Upper Laramie” of Veatch; many points in southern Colorado and north- ern New Mexico, in the Raton formation; the Bozeman coal field of Montana; and Black Buttes, Wyo., in beds believed by me to be of post-Laramie age. From the above account it appears that, although named from material of Laramie age at, Marshall, Juglans rugosa as it has come to be known is based on described and figured material from higher or post-Laramie horizons. There is no means of knowing just what the original Marshall leaves were like, beyond the fact already mentioned that they are said to resemble Juglans acuminata. It is for these reasons that Juglans rugosa is excluded from the Laramie flora. It appears to be essentially a Tertiary species, and its occurrence in Cre- taceous beds must be left open to subsequent discoveries. There is, of course, no certainty that the leaflets here described as Juglans pracrugosa are the same as the form to which Lesquereux gave the name of J. rugosa, and in fact they: do not differ from it very markedly. The leaves of J. praerugosa seem to have been thinner and do not appear particularly rugose. As a matter of fact, better material is needed before it can be completely diagnosed. Occurrence: Laramie formation, Marshall mine, Marshall, Colo., collected by Arthur Lakes, 1890. Hicoria angulata Knowlton, n. sp. Plate V, figure 4. Hicoria angulata Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 319, 1919. Fruit ovoid, truncate at base, obtusely pointed at apex, strongly several-angled (prob- ably four) or ridged. This beautifully preserved fruit is well shown in the figure. It is 22 millimeters long 6 U.S. Geol. Survey Bull. 163, 1900. THE FLORA, and about 14 millimeters in broadest diameter. If correctly interpreted, it should belong to that section of the living genus in which the husk or exocarp adheres closely to the shell and splits away only at maturity, and even then not to the extreme hase. In the material from Mount Carbon, near Morrison, there is another specimen of this species. It is of about the same shape as the one figured but is a little larger. _ Occurrence: Laramie formation, Marshall, Colo., railroad cut between old and new sta- tions, collected by A. C. Peale; Mount Carbon, near Morrison, Colo., collected by Arthur Lakes. Hicoria minutula Knowlton, n. sp. Plate V, figure 5. Hicoria minutula Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 320, 1919. Similar to the last but very much smaller. The length is 14 millimeters and the diameter about 9 millimeters. The husk, less than 1 millimeter thick, is apparently present, and in the apical portion it may be noted becoming fibrous or slightly frayed. It is not certain that this should be held as distinct from H. angulata, as it hardly differs except in size and may be only an immature specimen of that species. However, it can do no harm to consider them separately until further data can be procured. - Occurrence: Laramie formation, wooded bluff south of Marshall, Colo., collected by A. C. Peale, 1908. Order MYRICALES. _Family MYRICACEAE. Mpyrica torreyi Lesquereux. Myrica torreyi Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann, Rept. for 1872, p. 392, 1873; idem for 1876, p. 503, 1878; Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 129, pl. 14, figs. 3-10, 1878. Ward, U. S. Geol. Survey Sixth Ann. Rept., p. 551, pl. 40, fig. 4, 1886; idem, Bull, 37, p. 82, pl. 14, fig. 5, 1887. Knowlton, U. 8. Geol. Survey Bull. 163, p. 34, pl. 6, figs. 1-3, 1900.. Cockerell, Colorado Univ. Studies, vol. 7, p. 150, 1910. The type locality of this species is Black Buttes, Wyo., and all but two of the figured types are preserved in the United States Na- tional Museum (Nos. 138-142, inclusive), the others having been lost or misplaced. The species was well described and illustrated by Lesquereux, and none of the material since 123 obtained adds materially to our knowledge of it. Since the original finding at Black Buttes this species has been reported, on evidence of more or less value, as occurring at so many additional localities that it has largely been robbed of its value as a stratigraphic marker. Thus, Ward found it at Point of Rocks, Wyo., in beds now referred to the Mesaverde forma- tion. These specimens are illustrated in my “Flora of the Montana formation,” ® and al- though the leaves shown in figures 1 and 2 of that bulletin are probably correctly identified, that of figure 3 is more doubtful. What was presumed to be this species was found at Dunn’s ranch, 30 miles north of Laramie, Wyo., and also at Harper station, on the Union Pacific Railroad about 6 miles west of Dunn’s ranch. All these localities are now referred to the Mesaverde formation. The species has also been reported from the Mesaverde formation near Meeker, Colo., and the Vermejo formation at Rockvale, near Canon City, at La Veta, near Trinidad, and at Walsenburg, Colo. It has likewise been re- ported from the Lance formation of Converse County, Wyo., although the specimens found there are narrower than is usual. Occurrence: Laramie formation, Crow Creek, 25. miles southeast of Greeley, Colo. Post- Laramie (in my opinion), Black Buttes, Wyo. (types). ?Lance formation, Converse County, Wyo. Mesaverde formation, Point of Rocks, Wyo. Vermejo formation, Rockvale, La Veta, and Walsenburg, Colo. Myrica dubia Knowlton, n. sp. Plate V, figure 3. Myrica dubia Knowlton [nomen nudum], U. 8. Geol. Sur- vey Bull. 696, p. 394, 1919. Leaves small, lanceolate, obtusely wedge- shaped at base (apex destroyed); margin en- tire; midrib relatively thick; intramarginal vein well marked, other nervation consisting of thin, irregular veins connecting the midrib and intramarginal vein. This species is most closely related to Myrica torreyi Lesquereux * but differs in its smaller size, more obtuse base, and above all the per- fectly entire margin. 67 U.S. Geol. Survey Bull. 163, p. 34, pl. 6, figs. 1-3, 1900. 8 Lesquereux, Leo, U. 8. Geol. Survey Terr. Rept., vol. 7, pl. 16, figs. 3-10, 1878. 124 LARAMIE FLORA OF Occurrence: Laramie formation; Popes Bluff, just west of Pikeview, Colo. (sec. 14, T. 13 S., R. 67 W.), collected by A. C. Peale and M. I. Goldman, 1908. Myrtica oblongifolia Knowlton, n. sp. Plate XXI, figure 1. Myrica oblongifolia Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 396, 1919. Leaves membranaceous, long-elliptical, rounded to a slightly wedge-shaped base and to an obtuse apex; margin with numerous small, sharp teeth for the lower two-thirds, thence undulate and nearly entire to the apex; nervation paryphodrome, with a slender mar- ginal nerve around the leaf 1 millimeter from the border; slender nerves from the outside of this intramarginal nerve appear to enter the teeth; nerves very numerous, yet at an acute angle, irregular and broken, often joining, end- ing when they reach the border, in the intra- marginal vein; nervilles usually percurrent. This species is based upon the single fine specimen figured. It is about 8.5 centimeters long and 4 centimeters broad, with a petiole 0.5 centimeter long. It is a broad, long-elliptical leaf which is about equally rounded to both base and apex. The teeth begin within 1 centi- meter of the base, and are fine, sharp-pointed, and directed toward the apex. In the upper portion of the. blade the teeth are reduced to mere undulations, and at the apex the margin is.nearly entire. The most pronounced characteristic of this leaf is the strongly marked paryphodrome nervation—that is, a thin intramarginal nerve extending all around the leaf about 1 milli- meter distant from the margin. The other nerves, or secondaries, if they may be so called, are very numerous, at a low angle of divergence, and much broken and irregularly joined. It is difficult to determine the genus to which this leaf should be referred. There are a num- ber of living genera that have this peculiar paryphodrome nervation, as, for example, Tris- tania of the family Myrtaceae, Ardisia of the Myrsinaceae, and Dodonaea of the Sapinda- ceae, as well as many others less likely to be represented in a fossil state. On the whole it appears best to refer it to Myrica because it agrees in this character with many living spe- cies of the genus—for example, M. terebyuttacea Goppert, from tropical America, and Myrica THE DENVER BASIN. sp. from Brazil—and also because it is evi- dently allied to Myrica torrey: Lesquereux, a fossil species of wide vertical range which is also found in the Laramie. Myrica torreyi is undoubtedly the nearest relative of WM. oblongifolia that has not been described from material collected in this area. It differs, how- ever, in being narrowly lanceolate instead of broadly oblong and in being linear-acuminate instead of obtuse. The teeth in WV. torreyi are larger and more distant. This new species does not appear to be closely related to any of the other fossil Ameri- ican species of Myrica. It has much the shape and marginal dentation of Celastrophyllum de- currens Lesquereux, from the Dakota sand- stone, but that species differs absolutely in the nervation. Myrica oblongifolia is also in out- line and serration like the figures of Quercus haidingerit Ettingshausen given by Lesque- reux,” but that species also differs in nervation. Occurrence: Laramie formation, Marshall ‘mine, Marshall, Boulder County, Colo. Order SALICALES. . . Family SALICACEAE. Salix myricoides Knowlton, n. sp. Plate IV, figure 7. Saliz myricoides Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 569, 1919. Leaf linear-lanceolate, with a very long, slenderly acuminate apex and an apparently rather obtusely wedge-shaped base; margin entire; midrib relatively very thick; secon- daries very numerous, probably about 20 pairs, approximately at right angles to the midrib, each joining the one next above by a broad loop just inside the margin; finer nervation obsolete. The only example of this characteristic spe- cies observed is the one here figured. It is about 8 centimeters in length and 1 centimeter in maximum width; this width holds for more than half the length of the leaf. The leaf appears to have been rather thick, and as it is the upper side that is exposed, the nervation is obscured, all that can be made out being’ the very thick midrib and the numerous close, par- allel secondaries nearly at right angles to it. & Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 7, p. 156, pl. 20, figs. 9, 10, 1878. THE FLORA. Occurrence: Laramie formation, cut on Mof- fat railroad (Denver & Salt Lake) about 6 or 8 miles north of Golden, Colo., collected by A.C. Peale, 1908. Salix wyomingensis Knowlton and Cockerell. , Plate IV, figures 3, 4, 8. Salix wyomingensis Knowlton and Cockerell, U. 8. Geol. Survey Bull. 696, p. 572, 1919. ee Salix integra Géppert, Deutsch. geol. Gesell. Zeitschr., vol. 4, p. 493, 1852. Lesquereux, U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1873, p. 397, 1874; Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 167, pl. 7, figs. 1, 2, 1878. The American specimens on which is based the determination that this form occurs in the United States are included in the collections of the United States National Museum (No. 197) and are preserved on the red baked shale char- acteristic of a certain horizon at Black Buttes, Wyo. They agree fairly well with the Euro- pean figures of this species, and the species may be considered as probably present in this country. In the “Tertiary flora” Lesquereux mentions ‘a single example from Golden, Colo. This specimen is No. 837 of the United States National Museum collection and is preserved on a hard fine-grained whitish sandstone char- acteristic of the Laramie at Golden. This spe- cies is also represented by specimens from Coal Creek, Boulder County, Colo., one of the best preserved of which is shown in Plate IV, figure 8. In a collection made at Marshall by Peale there are a number of willow leaves, the most perfect of which are here figured (PI. IV, figs. 3, 4). nervation is obscure. So far as can be made out, however, they are the same as; the form figured by Lesquereux under the name Salix integra. It is to be noted that the leaves of Saliz are often lacking in diagnostic characters, and they are described with difficulty. Occurrence: Laramie formation, Golden, Colo., original collections studied by Lesque- reux; Coal Creek, Boulder County, Colo., col- lected by N. L. Britton about 1884; Marshall, Colo.,. collected by A. C. Peale, 1908. Post- Laramie (in my opinion), Black Buttes, Wyo. 85344 —22—_9 They are evidently fairly thick, but the 125 Salix brittoniana Knowlton, n. sp. Plate XXI, figure 8. Salix brittoniana Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 565, 1919. Leaf of firm texture, narrowly lanceolate, tapering below to a long, narrowly wedge- shaped base; apex not preserved; margin perfectly entire; nervation strong, pinnate, consisting of a relatively strong midrib and probably 8 or 10 pairs of alternate, remote secondaries, each of which arises at an acute angle, passes upward for a long distance, and disappears near the margin or unites by a slender apex to the secondary next above; nervilles none; finer nervation obscure but apparently consisting of a minute quadrangular areolation. The type of this species, and unfortunately the only one observed, lacks the upper portion of the leaf and would not be described as new except for the marked difference between it and anything else thus far noted in these beds. The portion observed, which includes the base, is 5.5 centimeters long and was possibly twice this length when perfect; the width does not exceed 1 centimeter. Its principal feature is the secondary nervation, described above. As regards size, shape, and margin this leaf is very much like many leaves that have been referred to Saliz angusta Al. Braun,” but it differs distinctly in the nervation; so also it agrees with S. amygdalaefolia Lesquereux as regards the type of secondary nervation but. differs in shape and margin. It is believed to be hardly worth while to follow resemblances further, as willow leaves are in general so variable, yet it is thought that this species, fragmentary as the type is, is sufficiently well marked to be readily recognized in the future. It has been named in honor of N. L. Britton, director of the New York Botanical Garden, who collected it. Occurrence: Laramie formation, Coal Creek, Boulder County, Colo. (Laramie), collected by N. L. Britton about 1880. 7 Cf. Lesquereux, Leo, The Tertiary flora: U. 8S. Geol. Survey Terr. Rept., vol. 7, pl. 22, fig. 4, 1878. 126 Populus? distorta Knowlton, n. sp. Plate IV, figure 6. Populus? distorta Knowlton [nomen nudum], U. 8. Geol. Survey Bull. 696, p. 488, 1919. Leaf of small size, unequal sided, probably more or less distorted or malformed, outline now. broadly ovate, possibly nearly circular when perfect, base abruptly rounded and truncate, apex obtusely acuminate; three- ribbed from the extreme base of the blade, midrib with about two pairs of thin secondary branches high up above the middle, lateral much arched outward, each with several thin branches on the outside. This form is represented by the single ex- ample figured, and this seems not. to be normal in that it was probably nearly circular in out- line when perfect, though now it is distinctly narrowed on one side. The length is 4.5 centi- meters and the width about 3 centimeters, though if the supposition of its abnormality is correct it should have been a little over 4 centimeters in width. This appears to be a poplar of the type of Populus arctica Heer “—that is, on the sup- position that one side has become reduced, probably by injury or pressure—but as it may be normal the reference to Populus has been questioned. Occurrence: Laramie formation, Cowan sta- tion, 10 miles south of Denver, Colo., collected by F. H. Knowlton. ‘ Order FAGALES. Family FAGACEAE. Quercus praeangustiloba Knowlton, ] Plate V, figures 6, 7 (types). Quercus pracangustiloba Knowlton, U. S. Geol. Survey Bull. 696, p. 535, 1919. Quercus angustiloba Al. Braun. Lesquereux, U. 8S. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 378, 1873; idem for 1873, p. 381, 1874; idem for 1876, p. 506, 1878; Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 161, pl. 21, figs. 4, 5, 1878. [Les- quereux’s original figures of these types are here reproduced.] The two specimens upon which this species is based, and apparently the only ones ever obtained, are in the collections of the United States National Museum (Nos. 191, 192). 7 Lesquereux, Leo, The Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, pl. 23, figs. 1-5, 1878. LARAMIE FLORA OF THE DENVER BASIN, They are preserved on the white fine-grained sandstone characteristic of the Laramie at Golden, Colo., and are rather obscure, though the figures given by Lesquereux and here reproduced show them very well. These leaves have until now been referred to the European Quercus angustiloba Al. Braun,” but as that species occurs in the Oligocene it seems inherently improbable that it should be common also to the American Upper Creta- ceous, though of course this is not in itself proof that they are not the same. In the matter of outline they are certainly very simi- lar, but the nervation is. obscurely retained in the European specimens, and until material is obtained showing them to be identical it seems best to treat them as distinct. These American leaves have a rather strong resemblance to certain leaves of Artocarpus. In‘ both the leaves under consideration, the strong secondaries next above the ones going to the lower lobes pass directly toward the sinuses, but it is impossible to see whether they enter the margin or pass around the sinus as intramarginal veins. In one of the larger lobes - there seems to be an intramarginal vein, as in Artocarpus, but it is too indistinct to be made the basis for transferring them to that genus. The specimen from Campbell’s quarry, Cross: Lakes, La., referred by Lesquereux ” to Quercus angustiloba, is also in the United States National Museum (No. 2551). It proves to be a minute ‘fragment without base, apex, or perfect sides and is absolutely worthless ® in determining the presence of this or any other species. Occurrence: Laramie formation, Colo. Golden, Quercus straminea Lesquereux. Quercus straminea Lesquereux, U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 373, 1873; Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 151, pl. 19, figs 6, 7, 1878. The type specimens of this species are pre- served in the United States National Museum (fig. 6 = No. 173, fig. 7=No. 174) and are on the hard sandstone matrix of the Laramie. These two specimens are so unlike that it was at one time thought best. to separate them; in fact; Lesquereux himself has called attention to this difference. On this point he says: 7” Braun, Al., in Ludwig, Rudolph, Paleontographica, vol. 8, p. 103, pl. 36, fig. 3, 1860. 73 U.S. Nat. Mus. Proc., vol. 11, p. 25, 1888. THE FLORA. These leaves seem to represent two different species. They have, however, a common character—that of the yellowish, shining secondary veins, which I have not seen on any other species of fossil plant of this locality. The leaf in figure 6 is smaller, with the secondary veins at 4 more acute angle of divergence; it has, however, the same character of nervation, shorter intermediate tertiary veins, ard more or less distinct veinlets, oblique to the secondary veins. In both leaves, also, the basilar veins are marginal and ascend to the branches of the secondary, nerves above. In a subsequent paper describing ' plants from the Denver formation Lesquereux ™ identified this species with question, saying: The leaf which I refer to this species is oval, apparently denticulate near the apex, and narrower than those fig- ured in Plate XIX, figures 6, 7.. It may, therefore, be- long to a different. species. I have not seen these forms, but to judge from the remarks quoted it would seem that they are properly excluded from Q. straminea. Occurrence: Laramie formation, Golden, Colo. Quercus eximia Knowlton, n. sp. Plate XXI, figure 2. Quercus eximia Knowlton [nomen nudum], U. 8. Geol.. Survey Bull. 696, p. 527, 1919. Leaf oblong-lanceolate, gradually or evenly narrowed from what appears to be about the middle of the blade to a long acuminate apex; margin provided with few distant upward-. pointing teeth; midrib very strong, running directly to the apex; secondaries alternate, 10 or more pairs in the upper half of the leaf, emerging at an angle of approximately 30°- 40°, some apparently entering the teeth but most of them arching to join the one next above, thence forming a practically continuous line just inside the margin; finer nervation en-. tirely obsolete. This species, which unfortunately is repre- sented only by the fragmentary example figured, must have been 18 or 20 centimeters long, for the portion preserved, which appears to be only about half of the leaf, is 11 centi- meters long. It is about 4 centimeters in greatest width and tapers gradually to an acuminate apex. One side of the leaf is pro- -vided with several rather prominent upward- pointing teeth; the other side is merely un- dulate with but faint indications of teeth. ™4 Lesquereux, Leo, Fossil plants collected at Golden, Colo.: Har- vard Coll. Mus. Comp. Zoology Bull., vol. 16, p. 46, 1888. 127 The secondaries are distinctly alternate, each usually—so far as can be made out—arching just inside the border to join the one next above by a sort of bifurcation in the upper portion, thus producing a nearly continuous intramarginal line, a character observed in certain living leaves of this genus. Among described forms this has a decided resemblance to Quercus lyelli Heer,” from the Atanekerdluk beds of Greenland. It is, for example, very close to the forms shown in Heer’s figures 7b of Plate LXX, 9 and 10 of Plate LX XII, and 1, 2, and 4 of Plate LX XIII, differing in the thicker midrib and stronger secondaries, which are more continuous and, so far as can be made out, less branched. The teeth in the two forms are very similar. There can be almost no question as to their generic identity, and but for a number of quite differ- ently appearing forms included by Heer in his species there would be little question of their specific similarity. Without more and better material I have thought it best to keep them apart. Occurrence: Laramie formation, Coal Creek, Boulder County, Colo. Quercus viburnifolia? Lesquereux. Quercus viburnifolia Lesquereux, Tertiary flora: U. 8. Geol. Survey Terr. Rept., vol. 7, p. 159, pl. 20, figs. 11, 12, 1878; U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1876, p. 505, 1878; Harvard Coll. Mus. Comp. Zoology Bull., vol. 16, p. 46, 1888. Ettingshausen, Roy. Soc. London Proc., vol. 30, p. 232, 1880. - Quercus triangularis Géppert [in part]. Lesquereux, U.S. Geol. and Geog: Survey Terr. Ann. Rept. for 1872, p. 377, 1873, Quercus attenuata? Goppert. Lesquereux, U. S. Geol. and Geog. Survey Terr, Ann. Rept. for 1873, p. 389, 1874. ‘One of the figured types of this species (the original of fig. 11 in the “Tertiary flora”) is preserved in the United States National Mu- seum (No. 186), together with the others that were the basis for Lesquereux’s remarks con- cerning this form. None of them are very per- fect, yet a careful study brings out well the characters upon which the species is founded. This original specimen is from Sand Creek, Colo., and others were reported from Golden, Colo., and Black Buttes, Wyo., the latter pre- served on red baked shale. The matrix of the % Flora fossilis arctica, vol. 7, pt. 1, p. 87, pl. 66, figs. 4, 5a; pl. 70, fig. 7b; pl. 72, figs. 1-10; pl. 73, figs. 1-6, 1883. 128 Golden specimen shows it to have come from the andesitic beds, probably on South Table Mountain, and no less than 11 additional exam- ples were found by Lesquereux in the collec- tion from these beds determined for the Museum of Comparative Zoology. This species has also been reported by Ettingshausen in the flora from Alum Bay, England. A number of well-preserved leaves apparently belonging to this species have been found in the material from Converse County, Wyo. They do not differ essentially from the type speci- men shown in Lesquereux’s figure 11. The basal portion of what appears to be a small leaf of this species has been found in material from Mount Bross, Middle Park, Colo., and a rather narrow but otherwise nearly nor- mal leaf is contained in the small collection made in the Laramie at Crow Creek, Colo. Occurrence: Laramie formation, Canfield ranch on Crow Creek, about 25 miles northeast of Greeley, Colo., collected by F. H. Knowlton and T. W. Stanton, June, 1896. Post-Laramie (in my opinion), Black Buttes, Wyo. Den- ver formation, Sand Creek, 18 miles east of Denver, Colo. (type); Golden, Colo. Lance formation, gulch south of Lightning Creek, opposite mouth of Box Elder Creek, Converse. County, Wyo., collected by T. W. Stanton, July, 1896. Order URTICALES. Family MORACEAE. Artocarpus lessigiana (Lesquereux) Knowlton. Plate XII, figure 1; Plate XXII, figure 4. ; Artocarpus lessigiana (Lesquereux) Knowlton, Science, vol. 21, p. 24, 1893; U. 8. Geol. Survey Bull. 152, p. 42, 1898. Myrica? lessigiana Lesquereux, U. S. Geol. and Geog. Sur- vey Terr. Bull., vol. 1, p. 386, 1876; idem, Ann. Rept. for 1874, p. 312, 1876. Myrica? lessigit LLesquereux, Tertiary flora: U. S. Geol. Survey Terr. Rept., vol. 7, p. 138, pl. 64, fig. 1, 1878; U. 8. Geol. and Geog. Survey Terr. Ann. Rept. for 1876, p. 503, 1878. Leaf very large, coriaceous, oblong, deeply |. pinnately lobed, the lobes opposite, oblong- lanceolate, pointed, at an open angle of diver- gence, separated usually to a point near the midrib, where they are joined by broad, rounded sinuses; midrib very thick; secondaries of two orders, the first strong, ascending to the points of the lobes and branched on either ‘of Artocarpus, LARAMIE FLORA OF THE DENVER BASIN. side, the second smaller, emerging from the midrib between the others, passing up to the sinus, where they divide into two branches that arch around the sinus just inside the margin and then follow the lobes in festoons, anastomosing with the tertiaries;. tertiaries numerous, alternate, curved more or less in passing to the margin, along which they form ‘long festoons just inside the border; ultimate areolation in the main quadrangular, formed by divisions at right angles to the tertiaries. These magnificent leaves were from 20 to 30 centimeters or more long and from 12 or 15 to 18 centimeters wide. They are thick, probably coriaceous, and broadly oblong, and the lobes are connected by broad, rounded sinuses. This species was first described by Lesquereux under the name Myrica? lessigiana from material collected on Coal Creek, Boulder County, Colo., where it was found just above the coal. It was obtained, according to Lesquereux, by Gen. W. H. Lessig, for whom it was named. For many years the location of the type specimen was unknown, but recently it came to light among the collections donated to the United States National Museum by R. D. Lacoe, of Pittston, Pa., and is now No. 7172 of the Museum collection. It was with great doubt that this specimen was referred to Myrica by Lesquereux,” who says: It is doubtful if this leaf represents * * * a species of the section of the Comptonia. It resembles Comptonia grandifolia Unger, which till now has been considered as the giant representative of this section but whose leaf is scarcely half as large as this. The reference of these leaves to the genus Artocarpus was first suggested by Nathorst 7 in his paper describing a new species of the genus from the Cenomanian of Greenland. After discussing a number of poorly defined fossil species and describing the new form (A. dicksoni), which he was fortunate enough to find associated with undoubted fruits, he calls attention to its resemblance to and possible identity with the Aralia pungens and Myrica? lessigir of Lesquereux. A compari- son of these leaves with leaves of living species particularly of the common breadfruit (A. ineisa), proves beyond. reason- 76 Lesquereux, Leo, U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, p. 312, 1876. ™ Nathorst, A.G., Ueber die Reste eines Brotfruchtbaums: K. svenska Vet.-Akad. Handl., vol. 24, p. 7, 1890, THE FLORA, able doubt that Nathorst’s supposition is correct, and they are consequently referred to this genus. In leaves of Artocarpus incisa before me the base is broadly wedge-shaped, and the distance to which the lobation extends decreases toward the apex, or just the reverse of what occurs in A. lessigiana. The nervation in the lobes is exactly the same as in the living leaf, including the arching of the tertiaries, the intramarginal nerve, and the secondary emerging from the midrib, dividing and pass- ing around on either side of the sinus. The Greenland species (A. dicksoni) seems to ap- proach more closely in outline to the living A. wncisa than the leaves under consideration. No fruits or flowers have been found in the Ameri- can deposits that can be referred to this genus. After the discovery of a well-authenticated species of Artocarpus in the Cenomanian of Greenland it was logical to expect to find rep- resentatives in later formations on the Ameri- can continent, and such has been shown to be the case. The genus is now confined in its native state to tropical Asia and the Malay Archipelago, though once extending as far north as latitude 70° in Greenland. In America it has been found in the Laramie and Denver formations of the Denver Basin, in the Vermejo and Raton formations of southern Colorado and northern New Mexico, in the Wilcox group of the Gulf region, and in the Miocene (auri- ferous gravels) of California. The form most closely related to Artocarpus lessigiana is undoubtedly A. dissecta Knowlton,” from the Vermejo formation at Walsenburg, Colo. This formis a leaf of large size, deeply cut into at least three pairs of opposite lobes, the lower pair remote from the ones next above and connected with them by an exceedingly narrow wing that is hardly more than the petiole. The lower pair of lobes are also curiously cut into almost to the midrib on the lower side, but the upper side is attached by the whole base. Otherwise the general outline, number, and shape of the lobes, as well as the type of nerva- tion of the lobes, are practically the same in | both, and, as I have pointed out in my paper on the flora of the Raton Mesa region, it is entirely possible that a series of leaves would show them to be identical. As the facts now stand, how- ever, it seems best to consider them as distinct. 78 Knowlton, F. H., U. 8. Geol. Survey Prof, Paper 101, p. 267, pl. 42, fig. 6, 1918. 129 Occurrence: Laramie formation, Coal Creek, Boulder County, Colo. (type), collected by W. H. Lessig, now in United States National Museum; Marshall, Colo., half a mile south of railway station, in first draw north of white sandstone bluff, just above the highest coal of the vicinity, collected by F. H. Knowlton and G. C. Martin, 1908; Cowan station, 10 miles south of Denver, Colo., collected by F. H. Knowlton. Artocarpus liriodendroides Knowlton, n. sp. Plate XXI, figure 3. ‘ Artocarpus liriodendroides Knowlton [nomen nudum], U.S. Geol. Survey Bull. 696, p. 100, 1919. Leaf of medium size and probably mem- branaceous in texture, deeply cut into at least three pairs of large, opposite, distant lobes, which are, with the exception of the lowest, attached by the whole, evenly expanded base, which continues along the petiole between the lobes as a narrow web or wing and also persists below the lowest pair of lobes nearly or quite to the base of the petiole; lowest segment ovate, rather obtuse, attached by about one-third of its width; primary midrib strong, straight, margined between and below the lobes by the narrow wing; nervation of lowest segment con- sisting of a plainly marked secondary that forms a “midrib” very near the center and four or five pairs of thin, alternate branches that form broad loops just inside the margin; nervilles anastomosing in all directions. This interesting specimen is, so far as known, the only one found in these beds. Unfor- tunately it is so fragmentary that its complete size and appearance can not be determined. The ‘portion retained is about 10 centimeters long, of which some 4 centimeters is taken up with the petiole below the lower pair of lobes; but, to judge from the undiminished thickness of the midrib above, it must have been con- siderably larger. The lower, nearly perfect lobe, which is attached by a narrowed base only 5 millimeters wide, is 3.5 centimeters long and 1.5 centimeters broad in the middle. The seg- ment next above is 2.5 centimeters broad at the ~ base and is preserved for a length of only-3 centimeters. None of the other lobes is as well preserved, though all appear. to be opposite. The nervation, marginal wing to the petiole, and other features are well shown in the figure. 130 This species is undoubtedly most closely related to Artocarpus dissecta Knowlton,” from the Vermejo formation near Walaenburg, Colo., with which it agrees in general type, though differing in a number of important par- ticulars. In the first place, although, of course, this difference is not of cardinal importance, it may be mentioned that Artocarpus dissecta is nearly twice the size of the present species. In A. dissecta the lower lobes are attached by the whole width of the segment, and the main secondary or ‘‘midrib” is very close to the lower margin, which gives the segment the appearance of being cut away on the lower side. In A. liriodendroides, on the other hand, the lower segment is attached by a much con- tracted base, and the ‘‘midrib”’ is practically central. In shape and major nervation the upper segments appear to be much the same in both forms. The petiolar wing connecting the segments is much more pronounced in A. liriodendroides and extends down the petiole below the lower segment for a greater distance than in A. dissecta. It is quite possible that if a series of specimens from both localities were available the two forms might be shown to approach more closely or even to combine, but with only a single example from each locality, the forms seem sufficiently distinct to warrant different names. The leaf here described has an undoubted resemblance to what has been called Lirioden- dron from. the Dakota sandstone of Kansas, being in a way intermediate between L. pinnatifidum Lesquereux *° and L. snowii Les- quereux.*' The former is described by its author as ‘‘pinnately, alternately lobed; lobes short, obtuse truncate or angular, abruptly narrowed into an obtusely lobate or subtruncate apex, separated by broad, unequal sinuses,” and the latter is described as ‘‘pinnately, hori- zontally divided into linear, obtuse lobes, distant and distinct for their whole length, attached by their whole base to the thick median nerve (petiole) like pinnules of a compound leaf.” The specimens upon which L. pinnatifidum is based are imperfect, so that it is not possible to make out the whole leaf with satisfaction, but it appears to have had at least three pairs 7” Knowlton, F. H., U. S. Geol. Survey Prof. Paper 101, p. 267, pl. 42, fig. 6, 1918. 80 Lesquereux, Leo, The flora of ‘the Dakota group: U. 8. Geol. Survey Mon. 17, pl. 27, figs. 4, 5, 1892. 81 Idem, pl. 29, figs. 1, 2. LARAMIE FLORA OF THE DENVER BASIN. of large, obtuse, irregularly, quadrangular, alternate lobes, which are separated by broad, rounded sinuses. The portion of the blade between the lobes is sufficiently broad to sup- port a considerable nervation, whereas in the Laramie species the interlobular margin or wing is too narrow to be provided with nerva- tion. Superficially the leaf of a oa adacache cas ahaa el Triceratops vies anjiesaciat doqusccenscemaceacnecs aaupese ee -- 26 Rose, Bruce, on Willowbunch coalarea, Alberta. 47 | mulatoma thompsoni White.............s..ccseceeeeeeeereeeeeres 85 Rulac crataegifolia Knowlton........2...2 20. ceceeee eee eeee neers 150 Tyrrell, J. B., on establishment of Edmonton and 'Paskapoo Ss. formations. Siaisie Gistainip ois pasisiaiale emnie’aise Mca ROC RES REMES: 44 Sabal campbelli? Newberry... .-.......2..----00--eeeeeceeeeeeeeee 91 montana Knowlton, Pl. ITI, fig.4.. . 90, 91, 119 U. sp. cf. S. montana Knowlton.............220 2s eee eee eee e eee 92 55 Sabalites grayanus (Lesquereux) Lesquereux .........--..--+-+--+ 119 134 Salicacese........-ccceeesecseeceecensececenes ony 16 159 Salicales..............-02.-0eeeeeeseeeeceeeee eee e cece ee eeerenees 124 | Unio Pic Sek dacrrasts ce cincteasicrat vaicloneee sesewatcne ceases 85 Salixamygdalaefolia Lesquereux........... steteeeensereeeerces 125 | Urtiealesascck eveceakerse gt ctoncemeawaceanedeg eiebaeaaeunaree abet 128 angusta Al Braun ~~ 25,125 brittoniana Knowlton, PI. KKY, fig. 8... 2.5... eee ee eee 90, 125 Vv. : Wlege USPC s scacancdecgumssansuear eeu reaueueeeenreeeen 125 a a PISLY, fei Vevesed asc esisauesedece 91, 124 Veatch, A. C., on geology of Carbon County, WYO: saiecsee ceewes es 60 wyomingensis Knowlton and Cockerell, Pl. IV, figs. 3, 4,8. 90, 91, 125 on. — s coral Wyoming area...............6-+ 30, a SAR Pap soot are oa are ticate rete ran ont eae cnoae ene params 23 on type section of Laramie San J ae Basin, N. Mex., geology of..... 69 on validity of term Laramie.........-.2...+-+s0+ee-e secre sees 17 Sapindaceae..........-.-.c--cesscceceeececee 150 | Vermejo formation, position and plants of......--...--.--++-.+++- 19 Sapindales............. 44g | Vertebrates of the Laramie Schizaeaceae 112 Viburnum dichotomum Lesquereux. Schultz, A. R., on gedlogy of Black Buttes area, Wyo. . 68 dilatatum Thunberg.. on geology of Lincoln County, Wy0........2..20ceeseeeeeeeee marginatum Lesquereux on geology of Point of Rocks area, Wy0 ........--2.20e0-000- platanoides Lesquereux... Scranton, Colo., coalat, stratigraphy of........ Viburnum? sp....---+++-+ Sequoia acuminata? Lesquereux, Pl. II, figs. 7,8.. Vitis olriki Heer ........ ene brevifoli Viviparus prudentia White sj OVONS HOG? os nuassonasrcnanasvessesveesaveraa vi duandeenews Brachvdant tis Whit 85 longifolia Lesquereux, Pl. III, fig. 3; PL. IV, fig. 2 23, 90,115 | Volsella (Brachydontes) regularis White...........-+--se+eeeeee+ magnifolia Knowlton 116 , w obovata? Knowlton........ 24 . reichenbachi (Geinitz) Heer, Pl. XX, figs. 1, 2.. 114 | Ward, L. F., history of Laramie problem by.........--.--------++ 3 Shoshone group, posttlon Of..2..0.s