| Tullock Member | |
|---|---|
| Stratigraphic range: Early Paleocene (Puercan) | |
| Type | Member |
| Unit of | Fort Union Formation |
| Underlies | Lebo Member |
| Overlies | Hell Creek Formation (MT), Lance Formation (WY) |
| Thickness | 90–400 m (Powder River Basin) |
| Location | |
| Region | Montana, Wyoming |
| Country | United States |
| Type section | |
| Named for | Tullock Creek |
| Named by | Rogers and Lee (1923) |
The Tullock Member is a geologic member in Montana and Wyoming, forming the lowermost part of the Fort Union Formation. It is also known less commonly as the Tullock Formation, forming part of the Fort Union Group.1 It preserves fossils dating back to the Paleogene period.
References
References
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
- "Geologic Unit: Tullock". National Geologic Map Database. United States Geological Survey. Retrieved 2025-06-01.