Summerville Formation
| Summerville Formation | |
|---|---|
| Stratigraphic range: Oxfordian | |
| Summerville Formation at the type locality at Summerville Point, east side of the San Rafael Swell, Emery County, Utah | |
| Type | Geological formation | 
| Unit of | San Rafael Group | 
| Sub-units | Bluff Sandstone | 
| Underlies | Morrison Formation | 
| Overlies | Todilto & Curtis Formations | 
| Thickness | 100 m (330 ft) | 
| Lithology | |
| Primary | Mudstone, sandstone | 
| Other | Gypsum | 
| Location | |
| Coordinates | 39°12′58″N 110°32′38″W / 39.216°N 110.544°W | 
| Approximate paleocoordinates | 31°54′N 54°42′W / 31.9°N 54.7°W | 
| Region | Four Corners, (Southwestern United States) | 
| Country | United States | 
| Extent | Henry Mountains, Paradox Basin | 
| Type section | |
| Named for | Summerville Point, Emery County, Utah | 
| Named by | James Gilluly & J.B. Reeside Jr. | 
| Year defined | 1928 | 
| Summerville Formation outcrops in Utah, Colorado and New Mexico | |
The Summerville Formation is a geological formation in New Mexico, Colorado, and Utah of the Southwestern United States. It dates back to the Oxfordian stage of the Late Jurassic.