| Fox Hills Formation | |
|---|---|
| Stratigraphic range: Late Cretaceous, | |
 A ridge capped by a sandstone bed of the Fox Hills Formation west of Limon, Colorado | |
| Type | Geological formation |
| Unit of | Montana Group (MT, ND) |
| Sub-units | Fairpoint member (SD), Trail City member (ND, SD), Timber Lake (ND, SD), Lincoln member (CO), etc. |
| Underlies | Lance (WY)/Hell Creek (MT)[1] Laramie Formation (CO) |
| Overlies | Pierre (USA)/Bearpaw (CAN)[1] Lewis Shale (WY, MT)[1] |
| Thickness | 75-225 feet |
| Lithology | |
| Primary | Sandstone |
| Other | Shale |
| Location | |
| Region | Alberta, Colorado, Montana, North Dakota, South Dakota and Wyoming |
| Country | United States/Canada |
| Type section | |
| Named for | Fox Hills between Cheyenne and Moreau Rivers, South Dakota |
| Named by | Meek and Hayden[1] |
| Year defined | 1862[1] |
The Fox Hills Formation is a Cretaceous geologic formation in the northwestern Great Plains of North America. It is present from Alberta on the north to Colorado in the south.
Fossil remains of dinosaurs, including tyrannosaurs, as well as large marine reptiles, such as mosasaurs, have been recovered from the formation.[2]
- ^ a b c d e "Geologic Unit: Fox Hills". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2017-02-13.
- ^ Getman, Myron RC (1994). "Occurrences of Mosasaur and other reptilian fossil remains from the Fox Hills Formation (Maastrichtian: late Cretaceous) of North Dakota" (Document). St. Lawrence University Dept. of Geology theses.