Como Bluff Historic District

Como Bluff Historic District
Name	Como Bluff Historic District
Nrhp type	hd
Caption	Fossil-rich strata at Como Bluff
Location	Sweetwater County, Wyoming, United States
Added	1973
Refnum	73001931

Como Bluff Historic District Como Bluff Historic District is a nationally significant paleontological and historic landscape on the Union Pacific Railroad main line in south-central Wyoming. The site is renowned for Late Jurassic vertebrate fossils, early fieldwork by the American Museum of Natural History, the Smithsonian Institution, and the University of Wyoming, and its role in the development of vertebrate paleontology and the bone wars era. As a designated historic district on the National Register of Historic Places, it preserves quarry sites, rail-related features, and stratigraphic exposures central to studies of Morrison Formation faunas.

Introduction

Como Bluff lies along a prominent east–west ridge adjacent to the Green River drainage and the Union Pacific Railroad, between the towns of Rock Springs, Wyoming and Lander, Wyoming in Sweetwater County, Wyoming. Its scientific fame dates to the late 19th century when collectors working for institutions such as the American Museum of Natural History, the Yale Peabody Museum of Natural History, and the Smithsonian Institution recovered abundant dinosaur remains. The site’s assemblage contributed to descriptions by paleontologists including Othniel Charles Marsh, Edward Drinker Cope, Arthur Lakes, and William Holland, influencing taxonomic frameworks used by later researchers such as Barnum Brown and Charles Whitney Gilmore.

Geography and Geology

The bluff is an elongated anticline of sedimentary rocks exposed in the Mesozoic stratigraphic column dominated by the Morrison Formation overlying the Summerville Formation and underlying the Cretaceous sequences. Field stratigraphers from the United States Geological Survey and petrographers affiliated with the American Museum of Natural History documented lithologies including fluvial sandstones, mudstones, and carbonate paleosols that hosted vertebrate remains. Regional geologic mapping by teams connected to the Rockefeller University patrons and surveys tied into transcontinental corridors like the Lincoln Highway and Transcontinental Railroad development, highlighting how transportation corridors influenced access to fossiliferous outcrops. Paleoenvironments reconstructed by researchers affiliated with institutions such as the Field Museum of Natural History and the Royal Society emphasize semiarid floodplain systems inhabited by sauropods, theropods, and ornithischians.

Paleontological Discoveries

Como Bluff yielded canonical Late Jurassic taxa including Apatosaurus, Brontosaurus, Diplodocus, Stegosaurus, Allosaurus, and Ceratosaurus, with early material communicated in publications by Othniel Marsh and catalogued in repositories such as the Yale Peabody Museum. Significant specimens figured in monographs and catalogs authored by museum curators including Henry Fairfield Osborn and collectors like Rudolf Zittel and Arthur Lakes. Local quarries revealed articulated skeletons, gastrolith occurrences, and theropod tooth assemblages that informed comparative anatomy studies by scholars at the British Museum (Natural History), the Smithsonian Institution, and the Academy of Natural Sciences of Philadelphia. Subsequent fieldwork recovered microvertebrate assemblages and trace fossils that linked Como Bluff faunas to contemporaneous sites such as Dinosaur National Monument, Cleveland-Lloyd Dinosaur Quarry, and the Morrison Formation type area.

History of Excavation and Research

Initial surface discoveries by Arthur Lakes and commercial collectors intersected with institutional rivalries epitomized by the bone wars between Edward Drinker Cope and Othniel Charles Marsh, prompting organized expeditions from the American Museum of Natural History, the Yale Peabody Museum of Natural History, and the United States Geological Survey. Field seasons overseen by field directors like Henry Fairfield Osborn and crews led by preparators such as Barnum Brown employed early field conservation techniques, shipping large specimens via the Union Pacific Railroad to eastern museums and universities. Twentieth-century research included systematic stratigraphic work by Charles Whitney Gilmore and vertebrate paleontology syntheses by Samuel Wendell Williston and John Bell Hatcher, later augmented by taphonomic and histological studies from scholars at the University of California, Berkeley and the Museum of Comparative Zoology at Harvard University.

Preservation and Museumization

Federal recognition of the area’s scientific and historic importance led to listing on the National Register of Historic Places and cooperative stewardship involving the Bureau of Land Management, the Wyoming State Historic Preservation Office, and local stakeholders in Sweetwater County, Wyoming. Major specimens recovered at Como Bluff are curated in institutions including the American Museum of Natural History, the Yale Peabody Museum, the Smithsonian Institution, the Field Museum, and state collections at the Wyoming Dinosaur Center. Interpretive efforts have been supported by partnerships with the National Park Service and academic outreach programs at universities such as the University of Wyoming and the Colorado School of Mines, while conservation measures address threats from erosion, unauthorized collecting, and rail-related land use managed through agreements with the Union Pacific Railroad.

Significance and Impact on Paleontology

Como Bluff’s fossil record fundamentally shaped late 19th- and early 20th-century systematic paleontology, biostratigraphy, and museum exhibition practices, influencing figures like Othniel Charles Marsh, Edward Drinker Cope, Henry Fairfield Osborn, and Barnum Brown. The site served as a benchmark for comparisons with global Jurassic assemblages studied by paleontologists from institutions including the Natural History Museum, London, the Muséum national d'Histoire naturelle, and the University of Tübingen. Research at Como Bluff contributed to the development of paleontological methodologies—field excavation, preparation, taxonomy, and taphonomy—employed by generations of scholars at the American Museum of Natural History, the Yale Peabody Museum of Natural History, and the Smithsonian Institution, leaving an enduring legacy in vertebrate paleontology and public science heritage.

Category:Historic districts in Wyoming Category:Paleontological sites of the United States Category:National Register of Historic Places in Sweetwater County, Wyoming