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| Cambrian - Conococheague limestone (1) |
| Carboniferous - Purslane sandstone; Rockwell formation; Pinkerton sandstone; Myers shale; Hedges shale (1) |
| Devonian - Catskill formation; Jennings formation; Romney shale; Oriskany sandstone; Helderberg limestone (1) |
| Geology -- United States --Maps (1) |
| Geology--Maryland--Maps (1) |
| Geology--Pennsylvania--Maps (1) |
| Geology--West Virginia--Maps (1) |
| Neogene - unnamed strata (1) |
| Ordovician - Juniata formation; Martinsburg shale; Beekmantown limestone (1) |
| Paleogene - unnamed strata (1) |