Wissahickon Formation; Lower Pelitic Schist (MDwlps;4)

Wissahickon Formation; Lower Pelitic Schist

(Formerly mapped as oligoclase facies of Wissahickon Formation.) Medium- to coarse-grained biotite-oligoclase-muscovite-quartz schist with garnet, staurolite, and kyanite; fine- to medium-grained semipelitic schist; and fine-grained granular to weakly schistose psammitic granulite; psammitic beds increase upward; apparent thickness 5,500 feet or more.

State	Maryland
Name	Wissahickon Formation; Lower Pelitic Schist
Geologic age	Late Precambrian (?)
Lithologic constituents	Major Metamorphic > Schist > Mica-schist > Biotite-schistMedium- to coarse-grained biotite-oligoclase-muscovite-quartz schist with garnet, staurolite, and kyanite; fine- to medium-grained semipelitic schist Minor Metamorphic > Granulite
Stratigraphic units	Wissahickon Formation; Glenarm Series
References	Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000. In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.
NGMDB product	NGMDB product page for 16548
Counties	Baltimore - Carroll - Harford - Howard - Montgomery - Prince George's - Baltimore

Wissahickon Formation; Lower Pelitic Schist

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.