Laramie Formation
| Laramie Formation | |
|---|---|
| Stratigraphic range: Maastrichtian, 69–68 Ma | |
| Type | Geological formation |
| Underlies | Arapahoe Formation |
| Overlies | Fox Hills Formation |
| Thickness | 200-400 ft (60-120 m) |
| Lithology | |
| Primary | Sandstone, mudstone, clay, coal |
| Location | |
| Region | Colorado |
| Country | United States |
| Type section | |
| Named by | Clarence King |
The Laramie Formation is a geologic formation of the Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains. The formation contains some of the oldest records of grass in western North America.