Glenarm Wissahickon"" formation

Lithologically similar to oligoclase-mica schist of the Wissahickon Formation (PZw), but also includes lenticular amphibolite bodies having ocean-floor basalt chemistry.
State Pennsylvania
Name Glenarm Wissahickon"" formation
Geologic age Probably lower Paleozoic
Lithologic constituents
Major
Metamorphic > Schist > Mica-schistlithologically similar to oligoclase-mica schist of the Wissahickon Formation (PZw)
Minor
Metamorphic > Gneisssome hornblende gneiss, augen gneiss (PZw)
Metamorphic > Amphibolitealso includes lenticular amphibolite bodies having ocean-floor basalt chemistry
Comments Digital map differences from 1980 printed map: name and map symbol changed from (Wissahickon Formation - eastern part) (Xw).
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 Chester - Delaware - Montgomery