| Reedsville Formation | |
|---|---|
| Stratigraphic range: Late Ordovician | |
 Outcrop of Reedsville Formation on south side of U.S. Route 522, Blacklog Gap, Huntingdon County, Pennsylvania. | |
| Type | sedimentary |
| Unit of | Chickamauga Group (TN only)[1] |
| Underlies | Bald Eagle Formation and Juniata Formation |
| Overlies | Antes Gap Shale, Trenton Limestone in TN and Utica Shale in WV |
| Lithology | |
| Primary | shale |
| Other | sandstone |
| Location | |
| Region | Appalachian Mountains |
| Extent | Maryland, Pennsylvania, Tennessee, Virginia,[2] West Virginia |
| Type section | |
| Named for | Reedsville, Pennsylvania |
| Named by | E. O. Ulrich[3] |
The Ordovician Reedsville Formation is a mapped surficial bedrock unit in Pennsylvania, Maryland, Virginia, West Virginia, and Tennessee, that extends into the subsurface of Ohio. This rock is a slope-former adjacent to (and stratigraphically below) the prominent ridge-forming Bald Eagle sandstone unit in the Appalachian Mountains. It is often abbreviated Or on geologic maps.
- ^ Harris, L.D., 1965, Geologic map of the Wheeler quadrangle, Claiborne County, Tennessee, and Lee County, Virginia: U.S. Geological Survey Geologic Quadrangle Map, GQ-435, 1 sheet, scale 1:24,000 http://ngmdb.usgs.gov/Prodesc/proddesc_903.htm
- ^ Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau
- ^ Ulrich, E.O., 1911, Revision of the Paleozoic systems: Geological Society of America Bulletin, v. 22, p. 281-680.