Frontier Formation
Geological formation in the United States
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The Frontier Formation is a sedimentary geological formation whose strata date back to the Late Cretaceous. The formation's extents are: northwest Colorado, southeast Idaho, southern Montana, northern Utah, and western Wyoming. It occurs in many sedimentary basins and uplifted areas.
Sub-unitsTorchlight Sandstone Member, Peay Sandstone Member
UnderliesCody Shale
OverliesMowry Shale, Thermopolis Shale
| Frontier Formation | |
|---|---|
| Stratigraphic range: Cenomanian-Coniacian | |
Frontier Formation in Utah (Dinosaur National Monument) | |
| Type | Geological formation |
| Sub-units | Torchlight Sandstone Member, Peay Sandstone Member |
| Underlies | Cody Shale |
| Overlies | Mowry Shale, Thermopolis Shale |
| Lithology | |
| Primary | Sandstone |
| Other | Shale |
| Location | |
| Region | North America |
| Country | United States |
| Extent | see text |
| Type section | |
| Named by | W. C. Knight, 1902[1] |

The formation is described by W.G. Pierce as thick, lenticular, grey sandstone, gray shale, carbonaceous shale, and bentonite.[2]
Dinosaur remains are among the fossils that have been recovered from the formation.[3]
Vertebrate paleofauna
- Nodosaurus textilis
- Stegopelta landerensis - "Partial postcranium, osteoderms, [and] fragments of skull."[4]
- Hadrosauroidea indet. Footprints (Upper)[5]