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The University of Wyoming

Department of Geology and Geophysics

Collection of Fossil Vertebrates
(a component of the Departmental Scientific Collections)

General Collection Description

General Description of the Collection of Fossil Vertebrates

This summary reflects the regional specialization of the Collection of Fossil Vertebrates. Many of the sub-collections are one-of-a-kind, scientifically unique in one or more ways. The sub-collections have been especially useful in interpreting the late Phanerozoic geologic and biologic history of the Rocky Mountain region. Within the Rockies, Wyoming's late Mesozoic and Cenozoic geologic history are by far the most completely known, statewide. Fossils within our collection, drawn from an unusually broad diversity of otherwise poorly sampled nooks and crannies among Wyoming's basins and mountain-flanks, have served uniquely important roles in paleobiological and depositional/paleotectonic research.

Examination of this summary illustrates the long-term effects of our philosophy of limited and controlled growth. Over the past 25 years, most additions have been driven by intentional commitments to the answering of specific research questions. We have considered acquisition of new materials merely for the sake of collection growth as a highly undesirable practice. We have neither adequate manpower nor financial resources to cope with massive annual influxes of new specimens. We have taken the perspective that collection growth should emphasize geographic areas within Wyoming, with focus upon application to geological problems of a genuinely pioneering nature. Because of these self-imposed restraints upon collection-building: 1) our holdings have grown at only moderate rates, appropriately driven we argue, by specific research needs; 2) many of our samples are unique; and 3) the overall facility has specialized strengths within particular geographic areas that frequently are well off the scientific beaten path.

Development of the collection through the past ten years illustrates effects of the guiding principles cited above. Since the summer of 1990, additions have come almost exclusively from the greater Hanna Basin, of south-central Wyoming. Prior to our work, the number of cataloged specimens of vertebrate fossils from the Hanna Basin could nearly be counted on the fingers of two hands. Paleontologists for more than a century had by-passed this area to reach the better known collecting-grounds of such places as the Green River, Wind River, and Bighorn basins.

Our original purpose in initiating searches in the greater Hanna Basin was to pioneer a biostratigraphic zonation of its extraordinarily thick, lithologically diverse Laramide strata. We found that the exposed section was locally highly fossiliferous with aquatic, semi-aquatic, and terrestrial nonmarine vertebrates. Our activities since 1990 have led to discovery of hundreds of new mammal-bearing sites. The Curator and his students are documenting a superposed sequence that represents Lancian (latest Cretaceous) through earliest Wasatchian (latest Paleocene-earliest Eocene) time. The thick, well-exposed lithologic sequences include productive localities that represent all of the expected North American Land Mammal "Ages" except the Clarkforkian and early phases of the Torrejonian. Our collections from the Hanna Basin now total thousands of specimens, and the samples from early Paleocene parts of the section rank among the world's most important. Development of the Hanna Basin collections has been closely related to revised geologic mapping. The linkage of a detailed biostratigraphy to new data on structural characteristics of the basin is leading to unexpected revelations about the fundamental nature and Laramide evolution of the eastern Green River Basin.

The crucial point here is that intentionally focused research has led to highly specialized, unique collections that are of extraordinary importance to the future of geological and paleobiological research in the Rocky Mountain region.

Annotated Listing of Collection's Components


Paleozoic vertebrates: fish (North American and European) and Permian tetrapods. The Paleozoic collection is useful mainly for purposes of teaching.


Triassic archosaurs from Popo Agie Formation of central Wyoming.

Mesozoic marine reptiles. Small, but important collections of ichthyosaurs, plesiosaurs, and nothosaurs from a variety of geological units across eastern Wyoming. Contains several type specimens.

Late Jurassic dinosaur collection. A small but historically important collection of dinosaur bones, collected principally in the late 1890s and early 1900s, by Wilbur Knight and William Reed. Previously, the collection was much larger, but had diminished through neglect, poor storage, and theft. Recent curation efforts have, however, increased the usefulness of the collection by reassembling a number of the bones that had previously become fragmented.

Trujillo thesis collection. Small vertebrates from a locality in the Late Jurassic Morrison Formation at Flat top Anticline in Carbon County, Wyoming; includes several varieties of mammals.

Wilson marine vertebrate collection (mainly sharks and rays) from the Late Cretaceous Mesaverde Formation of the eastern Bighorn Basin, north-central Wyoming.

Mammals and lower vertebrates from the "Mesaverde" Formation of east-central and southwestern margins of the Bighorn Basin. With exception of a small collection from the eastern basin housed at The American Museum of Natural History, these represent the only existing documentation of mammalian life during the late Campanian of north-central Wyoming.

Late Cretaceous dinosaur collections. These small collections consist of material from the type Lance Formation, as well as the Medicine Bow and Ferris Formations of the Hanna Basin.

Lance Creek, eastern Wyoming and Bug Creek, northeastern Montana lower vertebrate and mammalian collections (Late Cretaceous and earliest Paleocene). These include good representative samplings of the common species.

Webb Dissertation Collection, Lance Formation of the Bighorn Basin. Large collection of mammals and lower vertebrates from the Lance Formation of the Bighorn Basin's west-central margin (various "Hewett's Foresight" localities). This includes thousands of fully curated specimens (mostly isolated teeth), representing the largest single collection of North American Mesozoic mammals recovered from west of Wyoming's Powder River Basin. The mammals represent doctoral research by Mr. Michael W. Webb.

Breithaupt thesis collection. Late Cretaceous lower vertebrate and mammalian remains from Lance Formation of eastern Rock Springs uplift, southwestern Wyoming. This is the largest collection of Lancian small vertebrates from southwestern Wyoming.



Hartman thesis collection. Large collection of vertebrate fossils from the Paleocene Fort Union (= Polecat Bench) Formation of the southern Bighorn Basin, mostly mammals. This collection has its base in the mammal-bearing Lance Formation and includes a few specimens of Puercan age, but its principal importance is documentation of the transition between Torrejonian and Tiffanian land mammal ages.

Leite dissertation collection. Extensive mammalian collection from the Paleocene Fort Union Formation (= Polecat Bench) of the southwestern Bighorn Basin. Specimens are primarily from the "False Lance" locality. Sampled localities range in age, however, from the Puercan into Clarkforkian. This and the Hartman collection represent two of the three existing important samples of Paleocene mammals from the southern Bighorn Basin.

Wroblewski thesis, Burris thesis, Eberle dissertation, and Higgins dissertation collections. These include diverse samplings from the Late Cretaceous through late Paleocene section of the Hanna Basin, south-central Wyoming. Outside of a few specimens collected long ago by personnel from Eastern institutions, these represent the only documentation of vertebrate life from the entirety of the Hanna Basin's inordinately thick Upper Cretaceous and Paleogene stratigraphic sequence. Collections represent sampling from hundreds of localities, and involve thousands of specimens. A superb Cretaceous-Tertiary boundary collection exists, and the Paleocene samplings in general are developing into one of the world's most important assemblages recovered from that epoch.

Secord thesis collection. Mammalian and lower vertebrate fossils from late Torrejonian through late Tiffanian sites in the Carbon Basin of south-central Wyoming. These collections represent the only documentation of vertebrate life from the Carbon Basin, and provide the only source of evidence by which local deformation can be dated.

Fort Union Formation, Bison Basin. Part of the original Paleocene collection from the Fort Union of Wyoming's Bison Basin, east of southern tip of the Wind River Range. The collection also has additions from more recent fieldwork.

Swain thesis collection. Original "Swain Quarry" Torrejonian collection from the Fort Union Formation of the eastern Washakie Basin, south-central Wyoming. Also present is a representative part of J. K. Rigby Jr.'s dissertation collection (American Museum of Natural History) from Swain Quarry.

Twin Buttes collection. Original "Twin Buttes" Paleocene collection from the early Tiffanian Shotgun Member, Fort Union Formation of the northern Wind River Basin, central Wyoming. This is an especially diverse collection.

Winterfeld thesiscollection. Involves Paleocene vertebrates from the Fort Union Formation, eastern Rock Springs uplift. This is a major collection that represents the only thoroughly described Paleocene mammalian fauna from vicinity of the uplift.


Huerfano Basin collection. Small collection, useful in teaching, from the early Eocene sequence of the Huerfano Basin, southern Colorado.

Wind River Formation. Various Wasatchian collections from the Wind River Formation of the central Wind River Basin (north of Shoshoni and south of Moneta).

Roehler thesis collection. Original collections from the Wasatchian Wind River Formation of Bates Hole, east-central Wyoming.

Wasatch Formation of Fossil Basin, southwestern Wyoming. Collections of early Eocene vertebrates.

Prichinello and Davidson thesis collections. Early Eocene collections from the Wind River Formation of Cooper Lake area, Laramie Basin, southeastern Wyoming. These collections represent the only source of documentation of Wasatchian mammalian life from the basin.

Table Rock area. Original early Eocene collection from the Wasatch Formation of Table Rock area, northern Washakie Basin, south-central Wyoming. Represents a good reference assemblage, although others working in nearby areas now have far superior collections.

Roehler's "Golden Sand Locality." Early Eocene Wasatch Formation of the southwestern Great Divide Basin of west-central Wyoming. Until recently, this collection represented essentially the only major record of mammalian life in the Great Divide Basin during Eocene time.

Cathedral Bluffs Tongue of the Wastatch Formation, Washakie Basin. Small collections from Wasatchian and Bridgerian parts of the Cathedral Bluffs on the northeastern rim of the Washakie Basin, south-central Wyoming. This collection is one of the few available from the type Cathedral Bluffs sequence.

Bird Quarry collection. An assemblage of Eocene vertebrates from the Cathedral Bluffs Tongue of the Wasatch Formation from the northeastern Green River Basin, including nearly 300 elements of the bird Presbyornis.

Winterfelddissertation collection. Early Eocene mammals, lower vertebrates, and invertebrates from the Wind River and type Indian Meadows formations of the northwestern-most Wind River Basin. This is the largest and most important assemblage of fossils yet collected from the Indian Meadows Formation.

Witter collection. Fairly extensive collection of early Eocene mammals from the Willwood Formation, northern Bighorn Basin.

Bown dissertation collection. The largest, most complete, and most thoroughly documented collection from the Wasatchian Willwood Formation of the southern Bighorn Basin, north-central Wyoming. Provides the primary documentation of early Eocene terrestrial vertebrate life for that part of the state.

Green River Formation fish collections from Fossil Basin and the Green River Basin, southwestern Wyoming.

Amos thesis collection. Wasatchian, Bridgerian, and earliest Uintan mammals from the Wind River and type Wagon Bed formations of the southern Wind River Basin. A small but significant collection that includes the most comprehensive fauna yet recovered from the Wagon Bed Formation.

Whiskey Basin "Bridger A." Extraordinary collection of mammals from the generally poorly fossiliferous "Bridger A," lower Bridger Formation, middle Eocene sequence of Whiskey Basin, southwestern Wyoming. Involves three thesis collections supervised by P. O. McGrew.

Bridger Formation of the western Big Sandy area, northern Green River Basin, southwestern Wyoming; Eocene vertebrates.

Tabernacle Butte, Bridger Formation. Part of original collection plus much additional material from middle Eocene Bridger Formation of Tabernacle Butte and vicinity, northern Green River Basin, Wyoming. Collections exist from four major undescribed localities. The collections are particularly strong in mammals of minuscule size.

Oregon Butte, Bridger Formation. One of the few existing collections from the Bridger Formation in vicinity of Oregon Butte, northwestern edge of the Great Divide Basin, Wyoming.

Haystack Hills. Small reference collections of late Bridgerian and early Uintan large vertebrates from the Washakie Formation of the Haystack Hills area, northern Washakie Basin, south-central Wyoming.

Eaton thesis collection. Among the largest and best middle and late Eocene vertebrate fossil collections from the spectacular volcaniclastic sequence of the Absaroka Range, northwestern Wyoming. Important collections exist from the Willwood, Aycross, Tepee Trail, and Wiggins formations. The assemblages provide basic information needed to date the volcanic and depositional histories responsible for development of the southern Absaroka Range. Included is the only important collection from rocks unequivocally referable to the Wiggins Formation.

Latest Eocene Yoder Formation of the western High Plains sequence of southeastern Wyoming; small collection.


Kron thesis collection. Latest Eocene and early Oligocene vertebrate fossils from the White River Formation of "Dilts Ranch," an area of the southernmost Powder River Basin, east-central Wyoming. Includes important Chadronian microfaunal assemblages, including species such as epoicotheres that are rare elsewhere.

Dickson collection. Extensive assemblages of small mammals from the White River Formation near Crawford, northwestern Nebraska, involving the transition between Chadronian and Orellan land mammal ages.

Sundell collections of early Oligocene vertebrate fossils from east of Douglas, White River Formation of the southern Powder River Basin, Wyoming. Includes important articulated skeletons of small vertebrates such as amphisbaenians and snakes, plus what have been described as fossilized inner chambers of snake hibernacula.

Miscellaneous Chadronian and Orellan. Small but useful reference collections from Chadronian and Orellan localities in the White River Formation from vicinities of: a) "Mountain Home," southern crest of Medicine Bow Range; b) Bates Hole; c) Flagstaff Rim; d) Rattlesnake Hills region of Beaver Rim; and e) Lance Creek. All these localities are in the southeastern quarter of Wyoming.


Harrison Formation, Nebraska. Miscellaneous small collections representative of earliest Miocene (Arikareean) of western Nebraska and Monroe Creek Formation of southeastern Wyoming.

Goshen Arikareean. Small collection of excellently preserved Arikareean mammals, especially carnivores, from localities in southwestern Goshen Hole, southeastern Wyoming.

Marsland Formation. Miscellaneous collections of early and middle Miocene (Hemingfordian) mammals from eastern Wyoming and western Nebraska (upper parts of Marsland Formation).

Split Rock Formation. Representative collection of small and large mammals from Hemingfordian levels of the extraordinarily fossiliferous type Split Rock Formation, central Wyoming.

Saratoga Basin and Sierra Madre, south-central Wyoming. Only fossil mammals known from these areas. This material encompasses the middle to late Miocene, recovered from what has been re-mapped recently as Browns Park Formation.

Puentz Formation. Representative collection of fossil fish from the middle Miocene of Roland Heights, California

Tate collection and Cassiliano thesis collection. Includes mammals from Horse Creek Quarry (Harrison Formation, middle Miocene), Joe's Quarry (Marslandormation, late Miocene), and Trail Creek Quarry (Ash Hollow Formation, late Miocene). This collection, representing superposed strata, is from north of Cheyenne, Wyoming and is the only major collection from the local Miocene sequence.

Small mammals from Lemoyne Quarry, an excellent collection from the Hemphillian Ash Hollow Formation of western Nebraska.

Agate Springs Quarry. Large collection of Miocene rhinoceros and chalicothere materail from Harrison Formation in vicinity of Agate Springs, northwestern Nebraska.

Verdigre Quarry from the Valentine Formation (Hemphillian) of northeastern Nebraska. Represents a mammalian and lower vertebrate fauna of astonishing richness that served as basis for the classic taphonomic study published by M. R. Voorhies.


Hager dissertation collection. Large sample of mammals from the Pleistocene Donnelly Ranch site of southeastern Colorado.

Animal Trap Cave. Excellent, stratigraphically controlled collection of late Wisconsinin mammals from Larimer County, northeastern Colorado.

Bell and Horned Owl Caves. Representative collections from late Pleistocene caves, Laramie Basin, southeastern Wyoming.

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