Cleveland-Lloyd Dinosaur Quarry

Cleveland-Lloyd Dinosaur Quarry
Name	Cleveland-Lloyd Dinosaur Quarry
Caption	Quarry site in Utah
Location	Uinta Basin, Emery County, Utah, United States
Type	Dinosaur bonebed
Age	Late Jurassic
Period	Kimmeridgian
Discovered	1927
Excavations	Ongoing

Cleveland-Lloyd Dinosaur Quarry is a Late Jurassic bonebed in the Uinta Basin of Utah notable for an extraordinary concentration of Allosaurus remains and a diverse assemblage of contemporaneous taxa. Managed within the boundaries of the Cleveland-Lloyd Dinosaur Quarry Museum and administered by the Bureau of Land Management, the site has yielded critical data for understanding Morrison Formation ecosystems and paleoecology of the Kimmeridgian stage.

Geology and Location

The quarry lies within exposures of the Morrison Formation on the East Tintic Mountains-adjacent landscape of Emery County, Utah, near the San Rafael Swell and the Book Cliffs, positioned in the sedimentary context of a eolian and fluvial interbedded sequence correlating with other Late Jurassic localities such as Como Bluff and Dry Mesa Dinosaur Quarry. Stratigraphically, the bonebed occurs in a channelized deposit interpreted from lithologic comparisons to units described by geologists working in the Uinta Basin and by mapping teams from the United States Geological Survey. Regional tectonics associated with the Sevier orogeny influenced basin subsidence and sediment supply that controlled preservation at the site, while paleoclimatic reconstructions referencing oxygen isotope studies and comparisons with Solnhofen-age facies suggest seasonal aridity punctuated by episodic flooding.

History of Discovery and Excavation

Initial surface discoveries in 1927 were reported to collectors operating in Utah, prompting formal excavation campaigns led by institutions including the University of Utah, the Natural History Museum of Utah, and the Cleveland Museum of Natural History. Subsequent field seasons involved prominent paleontologists such as Barnum Brown-era contemporaries and later researchers affiliated with the American Museum of Natural History and the Smithsonian Institution, whose curatorial teams documented and transported specimens to collections at the University of Utah, Cleveland Museum of Natural History, and the Natural History Museum of Los Angeles County. Long-term projects coordinated with the Bureau of Land Management and academic partners standardized excavation, mapping, and cataloguing protocols in accordance with federal paleontological resource management practices developed after legislation like the Paleontological Resources Preservation Act.

Paleontology and Fossil Assemblage

The assemblage is dominated by Allosaurus fragilis specimens but also includes taxa such as Ceratosaurus, Camptosaurus, Stegosaurus, Apatosaurus, Camarasaurus, and smaller taxa comparable to material from Dry Mesa. Chelonian remains, crocodilian-like crocodylomorph elements, and isolated dinosaur eggshell fragments have been reported and compared to contemporaneous faunas from Garden Park and Fruita Paleontological Area. Comparative anatomical studies leveraging specimens in the collections of the American Museum of Natural History, Natural History Museum, London, and the Field Museum of Natural History have refined taxonomic assignments, feeding ecology interpretations, and body size estimations through techniques used in studies at Hell Creek Formation and Two Medicine Formation sites.

Taphonomy and Mortality Hypotheses

Taphonomic analyses integrate bone orientation, abrasion, weathering stages, and element representation to evaluate competing mortality hypotheses proposed by researchers from institutions such as the University of Utah and the Smithsonian Institution. Interpretations include predator trap scenarios analogous to modern tar pit assemblages like the La Brea Tar Pits, drought-induced attritional mortality comparable to models applied at Aucilla River and Rhinoceros Cave, and hydraulic concentration within ephemeral channels informed by sedimentological work from the United States Geological Survey and experimental taphonomy studies at the University of Chicago. Isotopic geochemistry and histological sampling conducted by teams affiliated with the University of Kansas and the University of Wyoming have been used to assess seasonality, age profiles, and stress markers supporting multi-causal explanations for the preponderance of carnivorous remains.

Research, Conservation, and Curation

Ongoing research integrates field excavation by university teams, museum curators from the Cleveland Museum of Natural History and the Natural History Museum of Utah, and laboratory analyses at facilities including the Smithsonian Institution's laboratories and the Denver Museum of Nature & Science. Conservation efforts follow standards established by the American Alliance of Museums and the Society for Vertebrate Paleontology for specimen stabilization, 3D scanning, and digital archiving; many specimens have been accessioned into collections at the Natural History Museum of Los Angeles County and the Field Museum of Natural History. Curation workflows employ CT scanning and morphometric analyses used in comparative projects with the Royal Ontario Museum and the Museum für Naturkunde, enabling virtual replication and international research access while balancing federal stewardship responsibilities overseen by the Bureau of Land Management.

Visitor Access and Interpretation

Public interpretation is provided on-site at the museum operated by the Bureau of Land Management in partnership with local institutions and includes exhibits, cast displays reminiscent of outreach efforts by the American Museum of Natural History, and educational programming modeled after museum initiatives from the Smithsonian Institution and the Natural History Museum, London. Access follows land use policies coordinated with Emery County, Utah authorities and visitor services echoing interpretive curricula developed by the National Park Service for paleontological sites such as Dinosaur National Monument. Guided tours, outreach lectures, and traveling exhibits have connected the quarry’s research to audiences reached through collaborations with the Cleveland Museum of Natural History, University of Utah outreach programs, and regional museums.

Category:Quarries in the United States Category:Morrison Formation Category:Late Jurassic paleontological sites