| State | Pennsylvania |
|---|---|
| Name | Wissahickon Formation |
| Geologic age | Probably lower Paleozoic |
| Lithologic constituents |
Major
Metamorphic > Schist > Mica-schistoligoclase-mica schist
Minor
Igneous > Plutonic > Graniticsome quartz-rich and feldspar-rich members due to various degrees of granitization.
Metamorphic > Gneiss > Hornblende-gneisssome hornblende gneiss, some augen gneiss
|
| References | Berg, T.M., Edmunds, W.E., Geyer, A.R., and others, compilers, 1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1, 2nd ed., 3 sheets, scale 1:250,000.Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources, Miles, C.E., and Whitfield, T.G., compilers, 2001, Bedrock Geology of Pennsylvania, edition: 1.0, digital map, scale 1:250,000. |
| NGMDB product | |
| Counties | Bucks - Delaware - Montgomery - Philadelphia |