Wissahickon Formation; Upper Pelitic Schist (MDwups;4)

Wissahickon Formation; Upper Pelitic Schist - (Formerly mapped as albite facies of Wissahickon Formation.) Albite-chlorite-muscovite-quartz schist with sporadic thin beds of laminated micaceous quartzite; coarsens from west to east; primary sedimentary structures include normal bedding, graded bedding, and soft-sediment deformational structures; apparent thickness 14,000 feet or more.

State	Maryland
Name	Wissahickon Formation; Upper Pelitic Schist
Geologic age	Late Precambrian (?)
Original map label	wups
Primary rock type	quartz-feldspar schist
Secondary rock type	quartzite
Other rock types
Lithologic constituents	Major Metamorphic > Schist > Quartz-feldspar-schist Incidental Metamorphic > Metasedimentary > Metaclastic > Quartzite
Map references	Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unit references	Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000. Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD
Geographic coverage	Montgomery