Nonmarine molluscs from the Chinle Formation, Dockum Group (Upper Triassic), of Bull Canyon, Guadalupe County, New Mexico
— Barry S. Kues

The Chinle Formation is an extensive and varied sequence of continental red beds deposited in fluvial, lacustrine, deltaic and floodplain environments across the southwestern United States from Utah and Arizona to north-central Texas. The Chinle is best known for its sporadic but sometimes spectacular assemblages of vertebrates, including early dinosaurs, thecodonts, therapsids, labyrinthodont amphibians and fishes, and for a diverse Late Triassic flora. Although nonmarine molluscs are locally common in the Chinle, they have been relatively little studied; nearly all references are isolated descriptions of a few species or passing mention of molluscs in papers dealing with other aspects of Chinle geology. In this paper, one gastropod and several unionid bivalve taxa are described and discussed from Chinle exposures in Bull Canyon, eastern Guadalupe County, New Mexico. All measured and illustrated specimens considered here are reposited in the University of New Mexico Department of Geology paleontology collection and bear UNM catalog numbers.