Foliated quartz diorite

Mainly dark-gray, medium-grained, well-foliated gneiss (locally strongly sheared, especially near contacts), composed of plagioclase, quartz, biotite, and hornblende, locally also pyroxene.
State Connecticut
Name Foliated quartz diorite
Geologic age Devonian in part, probably Ordovician in part
Lithologic constituents
Major
Metamorphic > Gneiss > Hornblende-gneissMainly dark-gray, medium-grained, well-foliated gneiss (locally strongly sheared, especially near contacts), composed of plagioclase, quartz, biotite, and hornblende, locally also pyroxene.
Comments Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Merrimack Synclinorium
References

Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.

NGMDB product
Counties Tolland - Windham