Bull Run Formation
| Bull Run Formation | |
|---|---|
| Stratigraphic range: Norian ~ | |
Layers of Balls Bluff Siltstone at a quarry near Manassas, Virginia | |
| Type | Geological formation |
| Unit of | Chatham Group |
| Sub-units | Balls Bluff Member, Groveton Member, Leesburg Member, Mountain Run Member, Haudricks Mountain Member |
| Underlies | Catharpin Creek Formation |
| Overlies | Manassas Sandstone |
| Lithology | |
| Primary | Mudstone |
| Other | Shale, sandstone, siltstone, conglomerate |
| Location | |
| Coordinates | 38°54′N 77°24′W / 38.9°N 77.4°W |
| Approximate paleocoordinates | 13°18′N 21°48′W / 13.3°N 21.8°W |
| Region | Maryland, Virginia |
| Country | United States |
| Extent | Culpeper Basin |
Bull Run Formation (the United States) Bull Run Formation (Virginia) | |
The Bull Run Formation is a Late Triassic (Norian) stratigraphic unit in the eastern United States. It is part of the Newark Supergroup, exposed in the Culpeper Basin of Virginia and Maryland. Fossil fish bones and scales have been found in outcrops of the formation's Groveton Member in Manassas National Battlefield Park.
The United States Geological Survey does not formally recognize the Bull Run Formation as a distinct formation, but its validity has been promoted by some paleontologists.