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| Carboniferous - Greene formation; Washington formation; Monongahela formation; Conemaugh formation; Ames limestone (1) |
| Geology -- Pennsylvania -- Allegheny County -- Maps (1) |
| Geology -- Pennsylvania -- Beaver County -- Maps (1) |
| Geology -- Pennsylvania -- Washington County -- Maps (1) |
| Geology -- United States --Maps (1) |
| Natural gas -- Pennsylvania -- Beaver County -- Maps (1) |
| Natural gas -- Pennsylvania -- Washington County -- Maps (1) |
| Neogene - Carmichaels formation (1) |
| Petroleum -- Pennsylvania -- Allegheny County -- Maps (1) |
| Petroleum -- Pennsylvania -- Beaver County -- Maps (1) |