| Cloverly Formation | |
|---|---|
| Stratigraphic range: | |
 Brightly colored strata of the Himes Member of the Cloverly Formation near Shell, Wyoming | |
| Type | Geological formation |
| Sub-units | Pryor Conglomerate, Little Sheep Member, Himes Member |
| Underlies | Thermopolis Shale |
| Overlies | Morrison Formation |
| Thickness | 150–400 ft (46–122 m) |
| Lithology | |
| Primary | Mudstone |
| Other | Conglomerate, sandstone |
| Location | |
| Region |  Wyoming,  Montana,
 Utah |
| Country |  USA |
| Type section | |
| Named for | Cloverly post office, Wyoming |
| Named by | Nelson 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]
- ^ 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.
- ^ U.S. Geological Survey (1993). "Geologic Unit: Cloverly". Retrieved 2014-12-23.
- ^ "National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)". www.nps.gov. Retrieved 2019-03-22.
Year designated: 1973