Harrell Shale
| Harrell Shale Group | |
|---|---|
| Stratigraphic range: Frasnian | |
| Type | Group | 
| Sub-units | Burket Shale | 
| Underlies | Brallier Formation, Sonyea Formation, Trimmers Rock Formation | 
| Overlies | Mahantango Formation, Millboro Shale, and Tully Limestone | 
| Lithology | |
| Primary | shale, sandstone | 
| Location | |
| Region | Appalachian Mountains | 
| Country | United States | 
| Type section | |
| Named by | Charles Butts, 1918 | 
The Devonian Harrell Formation is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.