Fordham Gneiss (C and D member)

fc: biotite-hornblende-quartz-plagioclase gneiss, quartz-feldspar lenses, amphibolite, biotite and/or hornblende-quartz-feldspar gneiss; fd: sillimanite-garnet schistose gneiss, quartzite.
State New York
Name Fordham Gneiss (C and D member)
Geologic age Precambrian - Middle Proterozoic
Lithologic constituents
Metamorphic > Gneissbiotite-hornblende-quartz-plagioclase gneiss, biotite and/or hornblende-quartz-feldspar gneiss, sillimanite-garnet schistose gneiss
Metamorphic > Amphibolite
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Comments Age change per USGS Lexicon website (ref. NY046). Unit is divided up into 6 units on printed map (f undivided, and fa - fe). Digital map also separates them out, but combines unit fd with unit fc due to unclear labeling on printed map? (hard to distinguish).

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250,000.

USGS Geologic Names lexicon found at:

NGMDB product
Counties Westchester