Hornblende Gneiss/ Amphibolite
Mica Schist/ Gneiss/ Amphibolite
Granite Gneiss/ Granite
Granitic Gneiss undifferentiated
Quartzite/ Mica Schist
Biotitic Gneiss / Mica Schist/ Amphibolite
Layered and massive amphibolite; locally includes hornblende migmatite and ultramafic pods.
Biotitic Gneiss / Amphibolite
Coarse to medium-grained biotite granite gneiss; locally includes thick bands of epidote and thin, small amphibolite bodies. Boundary between Rock Mills Granite Gneiss and Camp Hill Granite Gneiss arbitrarily defined.
Agricola Schist - biotiite +/- garnet +/- sillimanite-feldspar-quartz schist, interlayered with thin-bedded dark-brown hornblende amphibolite; contains pegmatite pods and veins.
Feldspathic biotite-hornblende gneiss with thin layers of amphibolite, calc-silicate rock, garnet quartzite, and muscovite schist; locally rich in manganese.
Banded amphibolite interlayered with chlorite schist, chlorite amphibolite, chlorite-actinolite schist, chlorite +/- magnetite quartzite, and actinolite quartzite; may include small ultramafic pods.