The Cooper Canyon Formation is a geological

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

Norian The Norian is a division of the Triassic Period. It has the rank of an age ( geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic ...

age in

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

and

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

.Weishampel, David B; et al. (2004).
Dinosaur distribution (Late Triassic, North America)
" In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 518–521. . Type area of the formation is situated in

Garza County, Texas Garza County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 5,816, of which most of the population were residing in Its county seat, and only incorporated municipality, Post. The county was created ...

. An equivalent formation in eastern

is named Bull Canyon Formation. Some researchers argue that the latter name should be abandoned. The formation consist of reddish

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, ...

and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.' ...

with lenses of

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

and

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** ...

. 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 Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...

remains.

Vertebrate fauna

Temnospondyls

Allokotosaurs

Archosaurs and related

Procolophonomorphs

Misc.

References

{{Reflist, refs= {{cite journal , title =The Cooper Canyon Formation (Late Triassic) of western Texas , author =Lehman T., Chatterjee S., Schnable J. , date =1992 , journal=The Texas Journal of Science , volume =44 , issue =3 , pages =349–355 , url =https://www.thefreelibrary.com/The+Cooper+Canyon+Formation+(Late+Triassic)+of+western+Texas.-a0128663777

Links

Bull Canyon Formation of Chinle Group
by USGS Triassic formations of New Mexico Triassic geology of Texas Norian Stage