| Foreknobs Formation | |
|---|---|
| Stratigraphic range: Frasnian - Famennian[1] | |
 Conglomerate from Foreknobs Formation, Rt. 994, near western side of bridge going over Raystown Lake, Huntingdon County, Pennsylvania | |
| Type | sedimentary |
| Unit of | Greenland Gap Group |
| Sub-units | Mallow Member, Briery Gap Sandstone Member, Blizzard Member, Pound Sandstone Member, and Red Lick Member |
| Underlies | Catskill Formation, or Hampshire Formation in VA |
| Overlies | Scherr Formation, or Brallier Formation in VA |
| Thickness | 1321 ft at type section |
| Lithology | |
| Primary | Siltstone, sandstone, shale |
| Other | Conglomerate |
| Location | |
| Region | Appalachian Mountains |
| Extent | Pennsylvania, Maryland, Virginia, West Virginia |
| Type section | |
| Named for | Fore Knobs of Allegheny Front |
| Named by | J. M. Dennison, 1970 |
The Devonian Foreknobs Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.