Granodiorite and Biotite Granite Gneiss

Light gray to pale green, fine-grained, granodiorite gneiss, and dark gray biotite granite gneiss with some augen gneiss; in places a sheared muscovite-biotite gneiss; local biotite schist bands; intruded by metadiabase feeder dikes of Catoctin Metabasalt.
State Maryland
Name Granodiorite and Biotite Granite Gneiss
Geologic age Precambrian
Lithologic constituents
Metamorphic > Gneissgranitic gneiss
Metamorphic > Metaigneous > Metaintrusive > Metadiabase

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

NGMDB product
Counties Frederick - Washington