| Harpers Formation | |
|---|---|
| Stratigraphic range: Cambrian | |
 Harpers Schist. Shows older folded schistosity parallel to bedding cut by younger cleavage inclined to bedding. | |
| Type | Metamorphic |
| Unit of | Chilhowee Group |
| Sub-units | Snowden Member (VA), Montalto Quartzite Member (PA) |
| Underlies | Antietam Formation |
| Overlies | Weverton Formation |
| Lithology | |
| Primary | Schist |
| Other | Phyllite, shale |
| Location | |
| Region | Appalachia, Mid-Atlantic United States, and Southeastern United States |
| Country | United States |
| Extent | Maryland, Pennsylvania, Virginia, [1] West Virginia |
| Type section | |
| Named for | Harpers Ferry, West Virginia |
| Named by | Arthur Keith (1894) [2] |
The Harpers Formation is a geologic formation in Maryland, Pennsylvania, Virginia, and West Virginia, consisting of schist, phyllite, and shale. It dates back to the early Cambrian period. It is considered part of the Chilhowee Group.
