| Fort Union Formation | |
|---|---|
| Stratigraphic range: Maastrichtian-Selandian (Lancian-Clarkforkian) ~ | |
 Fossils from the Fort Union Formation | |
| Type | Geological formation |
| Sub-units | Atwell Gulch, China Butte, Ekalaka, Lebo, lower Ludlow, Overland, Rock Bench Quarry, Sentinel Butte, Shotgun, Somber beds, Tongue River, Tullock, upper Ludlow, Polecat Bench Formation |
| Underlies | Wasatch Formation |
| Overlies | Hell Creek Formation, Lance Formation |
| Lithology | |
| Primary | Sandstone, shale |
| Other | Coal |
| Location | |
| Coordinates | 47°00′N 104°36′W / 47.0°N 104.6°W |
| Approximate paleocoordinates | 52°48′N 80°06′W / 52.8°N 80.1°W |
| Region | Montana, North Dakota Wyoming, Colorado |
| Country |  United States |
| Extent | Powder River Basin |
The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.[1]