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GLENN L. JEPSEN Dept. Geology, Princeton University, Princeton, N. J.

Eocene , Coprolites, and Plants in the Golden Valley Formation of Western North Dakota

Abstract: An early date for the origin of this early Tertiary biofacies indicate warm, humid, the Golden Valley Formation in North Dakota is swampy lowlands with subtropical forests bordering confirmed by the discovery of , amphib- sluggish streams. Montmorillonite in the formation ians, , birds, and mammals. Riparian and may represent ash from volcanoes to the west. aquatic animals and plants that were associated in

CONTENTS

Introduction 673 References cited 683 Acknowledgments 673 Salvinia preauriculata as an index fossil. . 675 Figure Age of the Kingsbury Conglomerate. . . 676 1. Distribution of the Golden Valley Formation Naming of the Golden Valley Formation. 677 in part of Stark County, North Dakota . . 674 of the Golden Valley Formation . 678 Vertebrates 678 Plate Facing Coprolites 680 1. Rocks and fossils of the Golden Valley Forma- Plants 681 tion, Stark County, North Dakota .... 676 "Hard Siliceous" layer 681 2. Coprolites from the Golden Valley Conclusions 682 Formation, Stark County, North Dakota . 677

faculty members and students from universities INTRODUCTION and other schools in Colorado, Connecticut, Recent discoveries of many fossil vertebrates Massachusetts, Montana, New Hampshire, in Stark County, western North Dakota, New Jersey, New York, North Dakota, Ohio, validate an early Eocene (Sparnacian, Wasatch- and South Dakota participated in a program of ian) age for the Golden Valley Formation prospecting for fossils and quarrying in the and extend the known geographic distribution Golden Valley beds on the margins of the of North American, early Eocene land- Little Badlands synclinal basin area southwest vertebrate faunas several hundred miles east- of Dickinson, North Dakota, in the Heart ward. River drainage system (Fig. 1). This project, At least 18 orders, 29 families, 38 genera, and as part of a larger investigation of early Ter- 39 species of vertebrates from the Golden tiary rocks and fossils in western states, was Valley Formation are now represented in col- undertaken to test the validity of the paleo- lections at Princeton University, and additional botanical evidence adduced by the late Roland explorations in the region will undoubtedly W. Brown for the Eocene age of the Golden increase this number. Data derived from these Valley Formation and to try to find vertebrate new occurrences and associations suggest many fossils to aid in dating and correlating the interesting speculations about the ecology, formation. climate, terrain, and biofacies of early Ceno- zoic time east of the Rocky Mountains. ACKNOWLEDGMENTS At various times during parts of each sum- While field research was in progress on the mer field season of 1958 to 1961, inclusive, Golden Valley Formation south of South

Geological Society of America Bulletin, v. 74, p. 673-684, 1 fig., 2 pis., June 1963 673

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Heart, North Dakota, many friends helped in Museum, Ekalaka, Montana; Leonard Radin- defining and resolving some of the numerous sky, Yale University; Peter Robinson, Univer- problems of paleoecology, , sedi- sity of Colorado; and Elwyn Simons, Yale mentology, and geomorphology that are pre- University. sented by the fossils and rocks of the area. For enthusiastic work with pick and shovel Especially useful suggestions and criticisms in and air compressor many student diggers de- the field were offered by Erling Dorf and serve a vote of thanks. Parish A. Jenkins, Jr., Donald Baird, Princeton University; William participated in the field work of two seasons E. Benson, National Science Foundation; and expanded his research into a senior thesis Robert Chaifee, Dartmouth College; H. D. (1961, Princeton Univ.) on the lithology, co- Holland, Jr., University of North Dakota; prolites, and paleoecology of the Golden Wilson M. Laird, State Geologist of North Valley Formation. Clara Langdon of Dickinson Dakota; Marshall Lambert, Carter County and John A. Dvorak of South Heart generously

103° |

I Twr White River Group -FORT UNION I Teg Golden Valley Formation

NORTH DAKOTA I Tft Tongue River Member of 0 Fort Union Formation

SENTINEL BUTTE I • A, B Fossil sites

Figure 1. Distribution of the Golden Valley Formation in part of Stark County, North Dakota. Modified from Benson (1951). Fossil vertebrate localities: A, White Butte Site; B, Turtle Valley Site

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provided home and camp accomodations for grown explosively and covers more than 200 some members of the field crews. Erling Dorf squares miles as a dense green floating carpet contributed the identifications and classifica- that is suffocating some of the fish and other tion of Golden Valley fossil plants herein listed, elements of the native aquatic biota (Huxley, and he plans to continue field work on the 1962). formation to extend the paleobotanical collec- The to Recent time range of the tions in preparation for additional publications genus is not unusual for plants but is very long about them. Richard Estes of Boston Univer- when compared with the duration of most sity helped identify and prepare a list of some mammalian genera. Despite Brown's insistence of the submammalian fossil vertebrates. that the putative absence of Salvinia from Princeton University supported this study floras is an actual circumstance and through the William B. Scott Research Fund not merely a function of luck in collecting, it for Vertebrate Paleontology. seems obvious that this hardy oval-pinnuled eventually will be found in Paleocene SALVINIA PREAURICULATA rocks, thus closing or narrowing this hiatus of AS AN INDEX FOSSIL many millions of years in its distribution. In Brown (1948a; 1948b; 1952; in Benson, numerous localities all conditions past and pres- 1952; in Benson and Laird, 1947) originally ent seem to be satisfied for its presence and based his conclusions about the age of the preservation in Paleocene sediments. Golden Valley Formation solely and tenuously Berry's interesting speculation (1930, p. 48) upon the known occurrences and the assumed, that the species Salvinia preauriculata spread but not certainly delimited, time range of a northward to Wyoming from equatorial Amer- water-floating fern, Salvinia preauriculata. He ica during Eocene time is not supported by the had perceived a curious and unexplained time known place-time distribution of its geological distribution of Salvinia; although it occurs in occurrences (late Cretaceous of Colorado; North America in late Cretaceous and early early early Eocene of northern Eocene sediments, as well as mid-Eocene and Montana, western North Dakota, and various more recent deposits, it has not been found in localities in Wyoming; late Wasatchian early the intervening Paleocene beds. During a Eocene of Tennessee; and mid-Eocene Bridger- period of many years Brown (1948a, p. 1169) ian of the western Wyoming Wind River "... collected thousands of fossil plant spe- basin). Neither does the pattern clearly support cimens from hundreds of localities in the the migration direction (west to east) men- Paleocene ..." and "... never found a Paleo- tioned as a possibility by Benson (1952, open- cene Salvinia." He discovered the "Cretaceous file report, U. S. Geol. Survey, p. 90-91) species" in the " 'Laramie' Formation (Lance)" Waves of territorial extension may have oc- near Craig, Colorado, and also noted the species curred very rapidly in either of these or in preauriculata as an element of lakeside or slack- other directions as areas were opened by ap- stream vegetation in the mid-Eocene (Bridger- propriate climatic conditions to the spread of ian, Lutetian) Aycross Formation of the Wind the species, but the known distribution in time River basin, Wyoming (Berry, 1930), as well as and area of the taxon is too coarse a measuring part of a coastal and lagoon-border flora in the device to determine such comparatively fine early Eocene (Wasatchian, Ypresian) Wilcox details of its geographical habits. Group in the Tennessee region. Berry (p. 48) A real, rather than merely an apparent, ab- said that the latter form is very similar to the sence of Salvinia from Paleocene strata in the living S. auriculata of Cuba and Central and United States is fully in accord with the pre- South America and, further, that S. zeillerifmm sumptive absence therefrom of several mam- the Sparnacian of the Paris basin is more similar malian groups such as artiodactyls, perisso- to S. freauriculata of the Wilcox than to any of dactyls, and adapid primates. None of these the later Tertiary forms. animals or their ancestors, however, are known Living representatives of various species of to have been present in America in Cretaceous Salvinia are found chiefly in quiet equatorial time, and their apparently sudden arrival in the waters in the Americas, Europe, and Asia. S. earliest Eocene strongly indicates a territorial auriculata, introduced into tropical Africa, has expansion or migration rather than a mere become a serious limnological problem in shift of ecologic conditions. Vertebrate paleon- Kariba Lake on the Zambezi River, the largest tologists for many years have eagerly but fruit- man-made lake in the world, where it has lessly sought (and will continue to search for)

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fossils of pre-Eocene forms that can be rec- prior to the time that the term and concept ognized as representing the populations from "Paleocene" was generally accepted in this which "dawn horses," "dawn cattle," and country. "dawn adapid primates" arose. The persistent In 1910 the U. S. Geological Survey officially failure to find any trace of these groups of regarded the Kingsbury Conglomerate as a mammals below certain levels in the terrestrial member of the Fort Union Formation of Tertiary rocks of the Rocky Mountain region Eocene age. A few years later Wegemann has led to the arbitrary placement of the (1917) correlated this "member" with part of Paleocene-Eocene time boundary at those posi- the interfingering "Wasatch," which term was tions. becoming as elastic and distorted and inac- This practice of using pulses of appearance of curate as "Fort Union." A U. S. Geological slow-evolving forms (such as species of pterido- Survey map of Wyoming (Campbell and phytes among plants) or the first appearance of others) in 1925 listed the Kingsbury as an more rapidly changing major animal taxa (such Eocene equivalent of the Wasatch. About a as artiodactyls and perissodactyls) to gauge the decade later Nace (1936) on oddly tenuous age or correlation of rocks involves circular and, by then, generally rejected evidence con- reasoning and confuses the useful attributes of cluded that the Kingsbury was of late ("up- rocks and fossils, or in more esoteric terms, the per") Paleocene age. Wilmarth (1938) rec- elements of lithofacies and biofacies. It is not ognized the consensus and placed the Kings- as obviously and grossly misleading, however, bury Conglomerate as a member of the as the formerly general practice of assuming , and this is the present that widespread time correlations of rocks could official opinion of the U. S. Geological Survey. be adequately based upon the evidences of Gidley's identification of the mammal jaw diastrophism; we now know that the pulses from the Kingsbury as Tricentes sp. (a primitive of a "single" diastrophism are usually long and carnivore) was questioned by Jepsen (1940); slow and that their effects move from place to with the concurrence of C. L. Gazin of the place with variable speed. The utility of such U. S. National Museum the specimen was re- dating procedures usually depends upon their studied and reassigned to a species of Diaco- acceptability; ultimately (and properly) most dexis, a genus of artiodactyl which had become problems about the age of strata whose age is in useful as an index of early Eocene age. Dorf question are resolved by vote. (1940) removed some of the discrepancies and fictions in the paleobotanical evidences of the AGE OF THE KINGSBURY ages of various rocks and fossils in the classic CONGLOMERATE Cretaceous-Tertiary border dispute by showing A case in point is the current consensus about that Knowlton's "Lance" flora was mixed—• the age of a correlative of the Golden Valley that through error and confusion it contained Formation, the Kingsbury Conglomerate on elements of late Cretaceous and Paleocene ages. the east flank of the Bighorn Mountains in This combination of Lance and Fort Union northwest Wyoming. Darton (1906) named the plants to form a single putative floral unit conglomerate and described it as part of the inevitably appeared (to anyone who accepted ' 'Cretaceous system'' but stated that fossil shells Knowlton's conclusions) to contradict the and plants from it do not indicate the precise stratigraphic record of the vertebrates. Dorf's age of the beds (p. 61-62). Three years later important discovery of the fallacy in the Stanton (1909) used J. W. Gidley's identifica- paleobotanical records removed the basis for tion of a fossil mammal, "Tricentes sp." as evi- the historic squabble and permitted the evi- dence that the conglomerate is of Fort Union dences from fossil plants to be harmonized with age, like correlative strata in Montana and New paleozoological conclusions about feasible Mexico. In the same year Knowlton (1909) boundaries between the Mesozoic and the vigorously declared his opinion based upon Cenozoic. "plant evidence" that the Fort Union Forma- Finally, Brown (1948a) concurred in the tion (including the Kingsbury, as perhaps a widely held opinion that the Kingsbury, in- "near-shore phase," and the dinosaur-bearing cluding the basal part, is Eocene (and not "Hell Creek beds" and "Ceratops beds") was older) because he found S. preauriculata in of Eocene age. This confusion of Mesozoic and interfingering carbonaceous shales. For added Cenozoic strata was not as extreme as it might testimony Hose (1955) reported that fresh- now seem, however, because Knowlton wrote water invertebrates, identified by T. C. Yen,

Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/74/6/673/3417004/i0016-7606-74-6-673.pdf by guest on 30 September 2021 Figure 1. View, toward northwest, of White Butte fossil locality (Fig. 1). C— Light-gray Chadron Formation of White River Group, early Oligocene; unconformably overlying GV — Golden Valley Formation, early Eocene (Wasatchian); P — fossil-plant horizon; HS — hard siliceous layer cap- ping main vertebrate fossil zone. Top of White Butte about 2700 feet above sea level

Figure 2. Freshly exposed unweathered Figure 3. Weathered and fractured mass of HS hard siliceous layer (HS) above thin car- layer at Turtle Valley fossil locality (Fig. 1), bonaceous layer (C) and light-pink and showing impression of tree limb or trunk. Pho- gray clays (V) that yield most of the tograph by F. A. Jenkins, Jr. vertebrate fossils from the Golden Valley Formation. White Butte fossil locality (Fig. 1)

ROCKS AND FOSSILS OF THE GOLDEN VALLEY FORMATION, STARK COUNTY, NORTH DAKOTA

JEPSEN, PLATE 1 Geological Society of America Bulletin, volume 74

Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/74/6/673/3417004/i0016-7606-74-6-673.pdf by guest on 30 September 2021 Figure 1. (A) Twig marks and scratches on surface; (B) average weathered specimen; (C) flattened example; (D) large curved specimen; (E) gas cavities; (F) marks of intestine on wavy cleavage surface; (G) scales of small garfish (Lepidosteus) (PU18182, A-G, about one half natural size)

Figure 2. Broken, pinkish-gray coprolite of reptilian carnivore with Figure 3. Same pinnule curved impression of pinnule of Salvinia preauriculata (PU18010, impression (PU18010 X 1.8) X 6)

VERTEBRATE COPROLITES FROM THE GOLDEN VALLEY FORMATION, STARK COUNTY, NORTH DAKOTA

JEPSEN, PLATE 2 Geological Society of America Bulletin, volume 74

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indicate an Eocene age for the conglomerate. Survey), as a result of correcting some of Concordance appears to have been reached, and Hennen's observations, logically regards as the prospects of continued harmony of evi- part of the Tongue River Member (of the dence seem good. The vote is unanimous. Fort Union Formation) with which it inter- tongues. In North Dakota and eastern Mon- NAMING OF THE GOLDEN tana most of the Tongue River member cor- VALLEY FORMATION relates, on the basis of fossil vertebrates, with When Leonard (1906) discussed the clays of the late Paleocene Tiffany of Colorado-New North Dakota he regarded the Fort Union Mexico and the Silver Coulee-Clark Fork Formation as part of the Laramie Formation levels of the Polecat Bench Formation in north- because the two had not been locally differen- west Wyoming. Some of the lower beds of the tiated, and he referred the overlying white fine Tongue River Member, however, in the Medi- clays, some of which are in the Golden Valley cine Rocks area of southeastern Montana and Formation, to the Tertiary. On a reconnaisance in Grant County (wrongly cited by the author, in 1905 Douglass visited the area of the Little 1940, p. 242, as Billings County), southern Badlands near Dickinson; he later (1909) com- North Dakota, are mid-Paleocene, correlative mented that some of the deposits there were with the Lebo Andesitic Member of the Fort early Oligocene but that Professor Knowlton Union Formation of central Montana, the on the basis of fossil leaves "... judges them to Torrejon Formation of New Mexico, and the be Eocene." At that time, before general ac- Rock Bench Quarry beds of northwest Wyo- ceptance of "Paleocene," it was common prac- ming. tice to regard the Fort Union as an Eocene The name Golden Valley Formation of unit. Leonard adhered to this concept in addi- North Dakota was finally applied by Benson tional publications from 1911 to 1930, and al- and Laird (1947) to the sands, shales, lignites, ways regarded the distinctive plastic clays and clays that are "definitely Eocene," overlie immediately under the highly fossiliferous the "Sentinel Butte shale member of the Fort White River Formation as the top of the Fort Union formation" and are overlain uncon- Union. formably by the "Oligocene White River Seager and others (1942), in trying to clarify group." A type area and section was designated and correct Kline's (1942) confused account of near the town of Golden Valley in Mercer the stratigraphy of North Dakota, followed the County not far from the hills north of Hebron erroneous practice of Thom and Dobbin (1924) where a U. S. Geological Survey party led by and others in treating the Sentinel Butte Benson first found Salvinia preauriculata in Shale as a lower member of the "Wasatch" 1947. Benson later (1949, 1952, open-file re- Eocene (above the Tongue River Member of port, U. S. Geol. Survey) divided the Golden the Fort Union) and listed an unnamed upper Valley Formation into a 15-35-foot-thick member of the "Wasatch Formation" includ- lower member, mainly composed of light- ing beds that appeared to contain volcanic ash colored kaolinitic clays and shales that are and bentonitic clay. Hennen (1943) approved locally stained to bright yellow-orange "marker of this concept of naming strata in the area. beds," and an upper member consisting largely It is worth noting that the early discussion of yellow to gray micaceous sands that have a by White (1883) about the presumed Wasatch maximum known thickness of about 150 feet. age of the strata at the top of Sentinel Butte, In 1954 he concluded that the sedimentary near the North Dakota-Montana border, is not in the lower member was transported really pertinent now, for although he concluded as kaolin from a western source of intensely that the rocks were the chronological equiva- weathered rocks and has undergone little or no lents or ' 'representatives" of the Green River chemical change since its deposition, perhaps in and Wasatch groups (and he was thus the first a large shallow fresh-water lake, as a blanket to say that "Wasatch" occurred in the area), many thousand square miles in extent in south- more recent work (for example, Hares, 1928) western North Dakota. (The pattern of scat- dates the capping rocks of Sentinel Butte as tered remnants of this deposit suggests that it early Oligocene. Even now the age of the im- may have had a much greater original distribu- mediately underlying is not es- tion.) tablished, but they, in turn, rest upon the He stated (1954, p. 387) that the strati- Sentinel Butte Shale (type locality) that graphic relationships and the plants "... of the Benson (1952, open-file report, U. S. Geol. Golden Valley formation as a whole indicate an

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early to middle Eocene age, and the lower Formation" of the Powder River basin in kaolinitic portion is almost certainly earliest Wyoming, the "Wasatch" strata in the Bear- Eocene, the time equivalent of at least a part paw Mountain area of north central Montana, of the Wasatch formation." the base of the "Red Desert Tongue" and of the Knight Member of the Wasatch Formation FOSSILS OF THE GOLDEN in south central Wyoming (Pipiringos, 1955; VALLEY FORMATION Gazin, 1962), and part of the Hiawatha Mem- ber of the Wasatch Formation in the Sand Vertebrates Wash basin, northwestern Colorado (McKenna, The project of prospecting for vertebrate 1960). fossils in the Golden Valley Formation was Most of the vertebrate fossils from the especially challenging because Benson (1952, Golden Valley Formation in Stark County open-file report, U. S. Geol. Survey) had have been found in two localities, about 7 miles stated that during several seasons of recon- apart, in the northwest periphery of the Little naissance field work in southwest North Badlands (Fig. 1). One of these localities Dakota the sum total of animal fossils collected (PL 1, fig. 1), named "White Butte Site" by U. S. Geological Survey parties consisted of (after a prominent erosion remnant about 3 a gar-pike scale, one unidentifiable fragment of miles southeast of South Heart and a few hun- a leg bone, and a few crushed gastropods. The dred yards north of a "White Butte" triangula- primary aim of the recent field work by tion station), is in the SW y± sec. 29 and NW }/± paleontologists in the Golden Valley Formation sec. 32, T. 139 N., R. 97 W (on both sides of an was a search for vertebrates and other materials east-west county road). The other locality, that would test the validity of Salvinia pre- about 8 miles southwest of South Heart lies in auriculata as an index fossil and be useful for the SW J4 sec. 16 and W Y2 sec. 21, T. 138 N., additional correlation and paleoecological de- R. 98 W. It was called "Turtle Valley Site" in ductions. There were, however, two additional field references, to indicate the great abundance objectives: (1) to determine whether the upper of the fossils most commonly found there. A member of the formation was of Wasatchian or, few maps of the area correctly show these sites as Brown had inferred, of Bridgerian provincial as included within the irregular outcrop band age and (2) to explore the possibility that the of the Golden Valley Formation that rims the whole formation was merely a deeply weath- central patch of the White River Oligocene ered, bright-colored phase of the top of the and is surrounded by the Tongue River Paleo- usually drab Tongue River strata of late cene, but most published maps indicate them Paleocene age, analogous to the "Interior as being in one or the other of the latter forma- Formation" in South Dakota which has proved tions (which stratigraphically enclose the to be but a weathered phase of the Pierre Shale. Golden Valley Formation). Such inaccuracies These goals were slowly reached and re- easily arise and are readily explained because ported to Brown who thus shared the satisfac- the gentle dip of the strata varies in direction tion of seeing most of his conclusions about the and angle, and each cartographer selects a Golden Valley Formation verified. Several slightly different set of strata! boundaries for hundred classifiable bones and teeth of verte- the Golden Valley Formation. brates, as well as several thousand scraps which Benson (1951) and Denson and Gill (1955) resist classification, were discovered in the upper mapped the southern part of Turtle Valley part of the formation, but the yield of verte- Site as being within the outcrop area of the brates from the lower member is only a few Oligocene "White River Group" and the nondescript fragments. An excellent collection White Butte Site as part of the Tongue River of fossil leaves was also secured from the upper Member of the Fort Union Formation. Cald- member, principally by Dr. E. Dorf and his well (1954) and Holland (1957) used even less assistants in 1961 and 1962. successful stratigraphic perimeters for their As an assemblage, the fossil vertebrates in- maps and included all of both localities in what dicate a close correlation of the Golden Valley they indicated as "White River Formation." Formation with the early Eocene rocks of The small-scale geologic map of North Dakota several areas, notably the early Wasatchian (Hansen, 1956) shows the White Butte locality Gray Bull beds (lower ) correctly enclosed within the limits of the of the Bighorn Basin in Wyoming, the Kings- Golden Valley Formation, but the southern bury Conglomerate Member of the "Wasatch part of the Turtle Valley Site is apparently

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mapped as White River. On the map by Freas Family ADAPIDAE (1962) the White Butte locality lies within the Pelycodus cf. P. ralstoni White River Formation. Family MICROSYOPIDAE Bones representing individuals in the fol- Cynodontomys cf. C. angustidens Order EDENTATA lowing taxa have been found at one or both of Family METACHEIROMYIDAE the two sites; ? Palaeanodon sp. Class TELEOSTOMI Order RODENTIA Order AMIIFORMES Family ISCHYROMYIDAE Family AMIIDAE Paramys cf. P. excavatus Kindleia [Stylomyleodon] sp. Lophiparamys cf. L. murinus Protamia [Pappichthys] sp. Order CARNIVORA Order LEPIDOSTEIFORMES Famdy HYAENODONTIDAE Family LEPIDOSTEIDAE sp. Lepidosteus sp. Family MIACIDAE Small teleostomes, incertae sedis sp. Miacis sp. Class AMPHIBIA Unidentified viverravine Order URODELA Order CONDYLARTHRA Family BATRACHOSAUROIDIDAE Family HYOPSODONTIDAE Balrachosauroides sp. loomisi Family AMBYSTOMATIDAE? H. cf. H. miticulus Undescribed genus and species Order PANTODONTA Order SALIENTIA Family CORYPHODONTIDAE Unidentified genus and species cf. molestus Class REPTILIA Order PERISSODACTYLA Order CHELONIA Family EQUIDAE Family DERMATEMYDIDAE Hvramtherium sp. Hoplochelys sp. Famdy ISECTOLOPHIDAE Family TESTUDINIDAE cf. H. protapirinus cf. Echmatemys sp. Order ARTIODACTYLA Family TRIONYCHIDAE Family DICHOBUNIDAE [Plastomenus] sp. ? Diacodexis sp. Order SQUAMATA Among the nonmammalian forms gar-pike Family VARANIDAE scales, amiid vertebrae, and turtle and croco- Saniwa cf. S. ensidens dilian bones are especially abundant; the most Family ANGUIDAE common mammalian remains (in order of de- Peltosaurus sp. Unidentified genus and species creasing incidence of discovery) represent the Order following taxa: Hyopsodus, Homogalax, Coryph- Family CROCODYLIDAE odon, Palaeosinopa, Tetonoides, and Hyraco- Crocodylus sp. therim. A similar sequence of diminishing rep- cf. Alligator sp. resentation within orders is: Condylarthra, cf. Procaimanoidea sp. Perissodactyla, Insectivora, Primates, Panto- Allognathosuchus sp. donta, Carnivora, Rodentia, Edentata, and Class AVES Artiodactyla. There is, of course, a correlation Small bird, incertae sedis between size of specimen and probability of Class MAMMALIA discovery, but the samples represent both Order INSECTIVORA quarry and surface recoveries. Family DELTATHERIDIIDAE The list is notable for some absences of cf. Didelphodus sp. vertebrate groups that usually occur, with Family LEPTICTIDAE abundant to rare frequencies, in similar collec- Palaeictops cf. P. tauri-cinerei tions from the early Wasatchian. To date no ? Leptacodon sp. traces have been found of multituberculates Family ERINACEIDAE? (either terrestrial or arboreal forms), marsu- cf. Entomolestes sp. pials, tillodonts (such as Esthonyx), dermoptera Family PANTOLESTIDAE Palaeosinopa sp. (Plagiomene), taeniodonts, large creodonts Order PRIMATES (oxyaenids, mesonychids), large condylarths Family ANAPTOMORPHIDAE (like Phenacodus), uintatheres, or large birds Tetonoides cf. T. pearcei (Diatryma). Perhaps significant also is the lack

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of remains of fresh-water sharks such as those mammals, such as coryphodons, which proba- found in various Paleocene and Eocene locali- bly ate only vegetation. Some dung of modern ties. [McKenna (1960, p. 10) reports finding alligators is similar in shape, size, and surface them in the Wasatchian of Colorado.] textures to some of the Golden Valley copro- One of the most puzzling features of the lites. fossil assemblage is the absence of large mam- Although the curved, gut-rippled and sphinc- malian carnivores, but this could be explained ter-pinched surfaces of many of the coprolites by the abundance of large nonmammalian are smooth, some show impressions of leaves forms that may have occupied the ecologic and stems, twigs (PL 2, fig. IA), sand grains, niches usually filled by mammalian terrestrial and small pebbles. Occasionally such structures predators. Some of the crocodilians, for exam- were even imbedded and surrounded by the ple, may have lived more on land than in water, outer part of the fecal masses, which therefore or their place in the extensive shallow pools and must have been quite plastic when they were swamps may have been unfavorable for land voided. The facts that occasional coprolites are mammals. Each type of reptilian carnivore flattened on one side (PL 2, fig. 1C) and that probably successively occupied, as it grew some (especially small ones) show many minute throughout its life, several of the ecologic surface striae also attest to such soft texture and niches which form discrete units in mammalian to deposition on a mat of plant debris or a sandy economy and are each held by a single kind of shore; the striae, compared with similar modern mammal of appropriate adult size. From ex- structures, appear to have been made by trapolation of skull dimensions it is estimated scatophagous beetles. that one of the Golden Valley crocodilians Within some of these excreta, especially in (Princeton Univ. no. 17258) reached a live smaller ones (as little as the eraser end of a pen- length of at least 10 feet. While this individual cil), are many unidentified objects, as well as developed from hatchling to its final size it was remains of partly disgested fish bones and able to secure progressively larger prey and thus scales (PL 2, fig. 1G), scutes and other take the place in nature that would be occupied bones, carbonized bits and impressions (molds) by several sizes of predatory mammals or birds of seeds and leaves and other parts of plants in somewhat different environs. that show delicate details of structure. One of the most interesting of such internal ghosts Coprolites represents a whole and intact leaf of Salvinia In addition to the fossils formed directly from preauriculata (PI. 2, figs. 2, 3) that presumably the structures of animals and plants, the rec- made an entire intestinal passage without being ords of some significant relationships of these changed by early Tertiary digestive juices and two life kingdoms to each other and to other peristaltic actions. This unusual occurrence of a aspects of their environment are also preserved botanical index fossil is more likely an adventi- in an interesting and unexpected way in the tious element in the fare of a swamp-living coprolites that weather out abundantly from reptilian carnivore than an unaccountably and the Golden Valley Formation (PI. 2). Some of selectively preserved part of the normal diet of these fossil feces, which have been found by the a mammalian herbivore. dozens, are comparatively large (up to 12 cm If some of the seeds in the coprolites can be long and 15 cm in circumference), irregular, identified as representing plants which today straight or curved, cylindrical masses, com- form zygotes seasonally, they may reveal in- monly with tapered ends (PI. 2, fig. IB). When formation about periodic levels of temperature fractured they reveal internal structures that and moisture in early Eocene time, or at least were impressed during accretion in the intestine about the time of year that some ancient meals (PL 2, fig. IF), as well as the undigested re- were eaten. mains of ingested materials. The shape, large From his X-ray diffraction study of the size, and texture of these fecal forms have led to Golden Valley ejecta F. A. Jenkins, Jr. (1961, a tentative conclusion that they pertained to senior thesis, Princeton Univ.) concluded that large carnivorous reptiles, whose bones are they were composed of some kind of "micro- common in the same sediments, rather than to crystalline opalite mineral," which suggests that some huge mammalian or avian carnivores or the original materials have been extensively or scavengers, whose bones are not yet known in totally replaced and cannot be accurately de- the Golden Valley paleobiota, or to other big termined now.

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14 genera of plants from the "lower member" Plants of the Golden Valley Formation but did not Fossil plants, especially leaf impressions in discuss their ecologic significance or their cor- excellent states of preservation, from the relative occurrences elsewhere. From the "up- "upper member" of the Golden Valley Forma- per member" Benson recorded only three tion are abundant in outcrops near White species of plants, Salvinia preauriculata, Cercidi- Butte. Dorf (personal communication, 1962) phyllum arcticum, and Quercus castaneopsis, and states that "This flora is clearly a northward cited (p. 91) Brown's speculation that the lat- extension of elements of the Early Eocene ter form might indicate correlation with the Wilcox flora which is widely distributed in the Green River Formation of mid-Eocene age. Gulf Coast states" and is similar to a plant as- semblage which he reported (1953) from the "HARD SILICEOUS" LAYER Willwood Formation of the Bighorn Basin of Most of the fossil vertebrates of the Golden Wyoming. Valley Formation have been found, fragmen- He has identified the following Golden Val- tary and scattered, 2-5 inches below a very ley forms "... subject to minor taxonomic re- distinctive, highly indurated and brittle layer visions pending further study." of chert which may represent a silicified peat- like deposit and which may have conditioned the preservation and chemical properties of Lygodium trilobatum Berry the fossils (PI. 1, figs. 2, 3). This layer, usually Salvinia preauriculata Berry Equisetes not more than 3-5 inches thick, is so hard and Equisetum sp. weather resistant that tabular pieces of it, Cycads? which have been cleaved into blocks by inter- Zamia? sp. secting joint systems in the layer, have been "let down" hundreds of feet, while the under- europaeus (Brongniart)_Heer lying rock has been eroded away, and are now Monocotyledones strewn about on the surface of the prairie many Cyperacites cf. C. wilcoxensis Berry miles from any outcrops of the layer in place in Musophyllum cf. M. complicatum Lesquereux its proper stratigraphic position. For conven- Dicotyledones Ailanthus, fruit ience of reference this rock, which is so persis- Anacarditest serratus Berry tent and widely distributed that earlier workers Banfcia? cf. B. compotonifolia Brown in the area thought it must occur in several B. saffordi (Lesquereux) Berry layers at different stratigraphic levels, was given B. tenuifolia Berry the informal descriptive field-note name of Bumelia cf. B. pseudohorrida Berry "hard siliceous layer" [or, in abbreviation, Carya cf. C. sessilis MacGinitie "HS" layer, to conform to the practice of Celastrus eolignitica Berry Caldwell (1954) and others]. C., n. sp. Early settlers picked the virtually imperish- C. cf. C. taurinensis Ward Cordial cf. C.? lowii Berry able blocks (averaging 4-18 inches in width and Cup'unites cf. C. loughridgii Berry in length) of this "field rock"from the arable Dillenites serralus Berry land and used them as natural building stones Dryophyllum annomalum Berry for farm houses and barns, many ruins of D. puryearensis Berry which still stand near the more recently built D. cf. D. tennesseensis Berry homes and outbuildings of wood. Amerindians Euonymus splendens Berry earlier used it to make large choppers and other Ficus mississippiensis (Lesquereux) Berry tools. Despite its hardness, its habit of breaking Juglans cf. /. alkahna Lesquereux into blocks prevents it from forming extensive Oreopanax cf. O. oxfordensis Berry Paliurus, fruit cap-rock structures, but it retards erosion Quercus sp. enough to form small ledges and "toadstool" Sapindus cf. grandifolius Ward forms in areas of active erosion. Ternstroemites lanceolatus Berry Unweathered parts of the HS layer are T. predaibornensis Berry usually dark browns and grays, although fresh upper and lower surfaces are commonly of Benson (1952, open-file report, U. S. Geol. much lighter ivory and light gray hues. Pro- Survey, p. 88) listed Brown's identifications of gressive weathering develops a slowly thicken-

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ing tan crust or patina and a powdery surface. sheets, lines, and mottled areas in it. These color A rough texture is imparted to the bottom and variations appear to be postgenetic and not a the top of the layer by the impressions of flat- feature of the original deposition. tened tree trunks and branches whose orienta- In a few places fossil bones and fish scales and tion might be a clue to the direction of Eocene coprolites have been found within a hand's water or wind currents in the region. No width above the chert layer; about 4 feet above vertebrate fossils have been found in the HS it a zone of tan claystone contains many ex- layer. Sections of it, however, reveal many frag- cellently preserved leaves, needles, and branch- ments of plants, some with discernible cell lets, as well as impressions of seeds and fruits, structures. Numerous cavities in the rock, now limonitized branches, and flattened cones. lined with small quartz crystals, were once oc- Most of the Golden Valley plants classified by cupied by flattened pieces of wood and bark. Dorf were taken from this layer at White Butte F. A. Jenkins Jr., (1961, senior thesis, Prince- locality (sec. 29). ton Univ.), through the results of X-ray and other analytic techniques, concludes that the CONCLUSIONS HS layer is a mosaic of microcrystalline silica Early Tertiary faunas are rarely found in and that the silica is authigenic, not detrital, association with floral fossils of sufficiently and may have been derived from a highly sili- good preservation to offer a satisfactory com- ceous volcanic ash. Abundant montmorillonite parison of the relative stages of evolution or to throughout the ' 'upper member" of the Golden permit a study of the interrelationships of the Valley Formation suggests the original presence elements in a total community of organisms there of volcanic ash which was probably car- (or "biome" of ecologists). The yield of verte- ried by winds and streams from volcanoes which brates and plants in numerous taxa from the were erupting far to the west. Freas (1962, p. Golden Valley Formation, therefore, provides 1352) suggests that there may be two types of a rare source for data on geobiotic conditions in montmorillonite in the "lower member" of the the western plains states during early Eocene Golden Valley Formation, "... one derived time. A successful search for fossil invertebrates from muscovite and another from a non- in the same strata in North Dakota would of micaceous material such as volcanic ash." course be a valuable extension of ecologic and The HS layer has a curious discontinuous dis- taxonomic studies. tribution, somewhat like that which water Further comparisons of the Golden Valley takes in small scattered pools on an almost flat flora with those from the Wilcox and from vari- but slightly irregular surface. Unlike the water, ous "Wasatch" localities will undoubtedly pro- however, the upper surface of the tabular chert duce more information, especially about cli- layer is not level, nor is the layer actually in a mates and plant associations, which can be com- plane. It thickens and thins, and its position pared with the evidence from vertebrate fossils has a vertical amplitude which may be several that western North Dakota in early Eocene inches or a foot or two within an area of an time was a warm, lush lowland with swamps acre. It deviates from the horizontal also, of and meandering streams bordered by dense course, with the regional dips. Some of the small vegetation. isolated discs of the layer look like little irregu- Lithic and biotic elements of the Golden lar flat blobs of crystallized maple sugar candy. Valley Formation apparently signify a geomor- Under the undulatory lower surface of the phic phase between the forested floodplains of layer is a thin sheet of coal (1 mm-1 cm thick, the Paleocene and the alternation of savannah PI. 1, fig. 2, C) on a highly carbonaceous mud- and forest which marks the early Eocene of the stone that grades downward into progressively areas farther to the west. Slow and uneven tec- lighter-colored shale and siltstone. This zone, a tonic pulses in central North America were few inches below the HS layer, is in many creating the incipient structures of the high places gray-yellow with numerous pink wavy plains and the Rocky Mountains.

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REFERENCES CITED Benson, W. E., 1949, Golden Valley formation of North Dakota (Abstract): Geol. Soc. America Bull., v. 60, p. 1873-1874 •—•— 1951, Geologic map of North Dakota southwest of the Missouri River: U.S. Geol. Survey, Prelim. map — 1954, Kaolin of early Eocene age in North Dakota: Science, v. 119, p. 387-388 Benson, W. E., and Laird, W. M., 1947, Eocene in North Dakota (Abstract): Geol. Soc. America Bull., v. 58, p. 1166-1167 Berry, E. W., 1930, Revision cf the lower Eocene Wilcox flora of the southeastern states: U. S. Geol. Survey Prof. Paper 156, 196 p. , ,, __ Brown, R. W., 1948a, Age of the Kingsbury conglomerate is Eocene: Geol. Soc. America Bull., v. 59, p. 1165-1172 •—•— 1948b, Correlation of Sentinel Butte shale in western North Dakota: Am. Assoc. Petroleum Geolo- gists Bull., v. 32, p. 1265-1274 •—•— 1952, Tertiary strata in eastern Montana and western North and South Dakota: Billings Geol. Soc. Guidebook, 3d Ann. Field Conf., Black Hills-, p. 89-92 Caldwell, J. W., 1954, Surface structure of western Stark County and adjacent areas of North Dakota: N. Dak. Geol. Survey Rept. Inv., no. 14, 1 sheet Campbell, M. R., and others, 1925, Geologic map of Wyoming: U. S. Geol. Survey Darton, N. H., 1906, Geology of the Bighorn Mountains: U. S. Geol. Survey Prof. Paper 51, 129 p. Denson, N. M., and Gill, J. R., 1956, Uranium-bearing lignite and its relation to volcanic tuffs in eastern Montana and North and South Dakota, p. 413-418 in Page, L. R., Stocking, H. E., and Smith, H. B., Compilers, Contributions to the geology of uranium and thorium by the U. S. Geological Survey and Atomic Energy Commission for the United Nations International Conference on Peaceful Uses of Atomic Energy, Geneva, Switzerland, 1955: U. S. Geol. Survey Prof. Paper 300, 739 p. Dorf, E., 1940, Relationship between floras of type Lance and Fort Union formations: Geol. Soc. America Bull., v. 51, p. 213-236 •—— 1953, Succession of Eocene floras in northwestern Wyoming (Abstract): Geol. Soc. America Bull., v. 64, p. 1413 Douglass, E., 1909, A geological reconnaissance in North Dakota, Montana, and Idaho; with notes on Mesozoic and Cenozoic geology: Carnegie Mus. Annals, v. 5, p. 211-288 Freas, D. H., 1962, Occurrence, mineralogy, and origin of the lower Golden Valley kaolinitic clay deposits near Dickinson, North Dakota: Geol. Soc. America Bull., v. 73, p. 1341-1364 Gazin, C. L., 1962, A further study of the lower Eocene mammalian faunas of southwestern Wyoming: Smithsonian Misc. Coll., v. 144, no. 1, 98 p. Hansen, M., Compiler, 1956, Geologic map of North Dakota: N. Dak. Geol. Survey Hares, C. J., 1928, Geology and lignite resources of the Marmarth field, southwestern North Dakota: U. S. Geol. Survey Bull. 775, 110 p. Hennen, R. V., 1943, Tertiary geology and oil and gas prospects in Dakota basin of North Dakota: Am. Assoc. Petroleum Geologists Bull., v. 27, p. 1567-1594 Holland, F. D., Jr., 1957, Guidebook for geologic field trip in the Dickinson area, North Dakota: N. Dak. Geol. Survey Misc. Ser., no. 5, 24 p. Hose, R. K., 1955, Geology of the Crazy Woman Creek area, Johnson County, Wyoming: U. S. Geol. Survey Bull. 1027-B, p. 33-118 Huxley, J., 1962, Eastern Africa: the ecological base: Endeavour, v. 21, p. 98-107 Jepsen, G. L., 1940, Paleocene faunas of the Polecat Bench formation, Park County, Wyoming, Part 1: Am. Philos. Soc. Proc., v. 83, p. 217-341 Kline, V. H., 1942, Stratigraphy of North Dakota: Am. Assoc. Petroleum Geologists Bull., v. 26, p. 336-379 Knowlton, F. H., 1909, The stratigraphic relations and paleontology of the "Hell Creek beds," "Ceratops beds" and equivalents, and their reference to the Fort Union formation: Washington Acad. Sci. Proc., v. 11, p. 179-238 Leonard, A. G., 1906, Stratigraphy of North Dakota clays: State Geol. Survey N. Dak. 4th Bienn. Rept., p. 65-94 •—— 1911, The Cretaceous and Tertiary formations of western North Dakota and eastern Montana: Jour. Geology, v. 19, p. 507-547

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Leonard, A. G., 1912, The geology of south-central North Dakota: State Geol. Survey N. Dak. 6th Bienn. Rept., p. 21-99 Leonard, A. G., and others, 1930, Geology and natural resources of North Dakota: Univ. N. Dak. Dept. Bull. 11, v. 14, no. 1, 64 p. McKenna, M. C., 1960, Fossil Mammalia from the early Wasatchian Four Mile fauna, Eocene of north- west Colorado: Univ. Calif. Pub. Geol. Sci., v. 37, p. 1-131 Nace, R. L., 1936, Summary of the late Cretaceous and early Tertiary stratigraphy of Wyoming: Wyo. Geol. Survey Bull. 26, 271 p. Pipiringos, G. N., 1955, Tertiary rocks in the central part of the Great Divide Basin, Sweetwater County, Wyoming: Wyo. Geol. Assoc. Guidebook, 10th Ann. Field Conf., Green River Basin, p. 100-104 Seager, O. A., and others, 1942, Discussion, stratigraphy of North Dakota: Am. Assoc. Petroleum Geolo- gists Bull., v. 26, p. 1414-1423 Stanton, T. W., 1909, The age and stratigraphic relations of the "Ceratops beds" of Wyoming and Mon- tana: Washington Acad. Sci. Proc., v. 11, p. 239-293 Thom, W. T., Jr., and Dobbin, C. E., 1924, Stratigraphy of Cretaceous-Eocene transition beds in eastern Montana and the Dakotas: Geol. Soc. America Bull., v. 35, p. 481-506 Wegemann, C. H., 1917, Wasatch fossils in so-called Fort Union beds of the Powder River basin, Wyoming, and their bearing on the stratigraphy of the region: U. S. Geol. Survey Prof. Paper 108-D, p. 57-60 White, C. A., 1883, On the existence of a deposit in northeastern Montana and northwestern Dakota that is possibly equivalent with the Green River group: Am. Jour. Sci., 3d. ser., v. 25, p. 411-416 Wilmarth, M. G., 1938, Lexicon of geologic names of the United States: U. S. Geol. Survey Bull. 896 pt. 1, 1244 p.

MANUSCRIPT RECEIVED BY THE SOCIETY, JUNE 19, 1962

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