| Juniata Formation | |
|---|---|
| Stratigraphic range: Late Ordovician | |
 Outcrop on U.S. Route 522 at Blacklog Narrows southeast of Orbisonia, Pennsylvania. | |
| Type | sedimentary |
| Underlies | Oswego Formation and Tuscarora Formation |
| Overlies | Bald Eagle Formation |
| Thickness | 400–1,125 ft (122–343 m) |
| Lithology | |
| Primary | sandstone, siltstone, shale |
| Location | |
| Region | Appalachian Mountains |
| Extent | Maryland, Pennsylvania, Tennessee, Virginia,[1] and West Virginia |
| Type section | |
| Named for | Juniata River in Pennsylvania |
| Named by | Darton and Taff[2] |
The Ordovician Juniata Formation is a mapped bedrock unit in Pennsylvania, West Virginia, Virginia, Tennessee, and Maryland. It is a relative slope-former occurring between the two prominent ridge-forming sandstone units: the Tuscarora Formation and the Bald Eagle Formation in the Appalachian Mountains.
- ^ Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau
- ^ Darton, N.H., and Taff, J.A., 1896, Description of the Piedmont sheet (West Virginia-Maryland): U.S. Geological Survey Geologic Atlas of the United States, Piedmont folio, no. 28, 6 p.