The Cooper Canyon Formation is a geological formation of Norian age in Texas and New Mexico. It is one of several formations encompassed by the Dockum Group.
The type area of the formation is situated in Garza County, Texas, southeast of Lubbock. The Cooper Canyon Formation consist of reddish siltstone and mudstone with lenses of sandstone and conglomerate. Thickness of the formation in the type area is 161.5 meters. It increases to the south, and in some places exceeds 200 m. The formation contains diverse fossils, including vertebrate remains.
Regional equivalents
The Bull Canyon Formation in eastern New Mexico is equivalent to the upper part of the Cooper Canyon Formation. Some researchers argue that the latter name should be abandoned. The middle and lower parts of the Cooper Canyon are correlated to the Trujillo and Tecovas formations (respectively) further north in the Texas Panhandle. The lowermost part of the Cooper Canyon Formation may also be correlated to the Colorado City Formation further south at Otis Chalk (Howard County).
Vertebrate fauna
Temnospondyls
Archosaurs
Phytosaurs
Pseudosuchians
Ornithodirans
Numerous bones from ornithodirans have been discovered throughout the Cooper Canyon Formation but cannot be assigned to specific genera or clades. However, they are at least variably identifiable as lagerpetids, dinosauromorphs, dinosaurs, saurischians and theropods.
Archosauromorphs
Fragmentary fossils are identifiable as archosauromorphs, namely members of the Allokotosauria+Prolacerta+Archosauriformes clade.
Other amniotes
Numerous fragmentary limb bones of various reptiles have been collected that cannot be reliably diagnosed to specific clades, though some show similarities to drepanosauromorphs.