Cloverly Formation

Cloverly Formation
Stratigraphic range: Valanginian-Cenomanian
Brightly colored strata of the Himes Member of the Cloverly Formation near Shell, Wyoming
TypeGeological formation
Sub-unitsPryor Conglomerate, Little Sheep Member, Himes Member
UnderliesThermopolis Shale
OverliesMorrison Formation
Thickness150–400 ft (46–122 m)
Lithology
PrimaryMudstone
OtherConglomerate, sandstone
Location
Region Wyoming,  Montana,

 Colorado,

 Utah
Country USA
Type section
Named forCloverly post office, Wyoming
Named byNelson Horatio Darton, 1904[1]

The Cloverly Formation is a geological formation of Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904.[1][2] The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service.[3]

  1. ^ a b Darton, N.H. 1904. Comparison of the stratigraphy of the Black Hills, Bighorn Mountains, and Rocky Mountain Front Range. Geological Society of America Bulletin, v. 15, p. 379-448.
  2. ^ U.S. Geological Survey (1993). "Geologic Unit: Cloverly". Retrieved 2014-12-23.
  3. ^ "National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)". www.nps.gov. Retrieved 2019-03-22. Year designated: 1973