| Sentinel Butte Formation | |
| Type: | Formation |
| Age: | Thanetian ~ |
| Period: | Thanetian |
| Region: | North Dakota |
| Unitof: | Fort Union Formation |
| Underlies: | Golden Valley Formation |
| Overlies: | Bullion Creek Formation |
The Sentinel Butte Formation is a geologic formation of Paleocene age in the Williston Basin of western North Dakota.[1] It preserves significant assemblages of non-marine plant and animal fossils.