Trap Falls Formation plus Ordovician? granitic gneiss

Trap Falls Formation (may be equivalent in part to Golden Hill Schist) - Gray to silvery, partly rusty weathering, medium-grained generally well layered schist, composed of quartz, sodic plagioclase, biotite, muscovite, and garnet, locally with sillimanite or kyanite, interlayered with two-mica gneiss and granulite and with amphibolite. Ordovician? granitic gneiss (including local terms Ansonia, Mine Hill, "Tyler Lake," "Siscowit") - White, light-gray, buff, or pink, generally foliated granitic gneiss, composed of sodic plagioclase, quartz, microcline, muscovite, and biotite, and locally garnet or sillimanite. Commonly contains numerous inclusions or layers of mica schist and gneiss.
State Connecticut
Name Trap Falls Formation plus Ordovician? granitic gneiss
Geologic age Middle or Lower Ordovician
Lithologic constituents
Major
Metamorphic > GneissTrap Falls Formation (may be equivalent in part to Golden Hill Schist) - interlayered with two-mica gneiss. Ordovician? granitic gneiss (including local terms Ansonia, Mine Hill, "Tyler Lake," "Siscowit") - White, light-gray, buff, or pink, generally foliated granitic gneiss, composed of sodic plagioclase, quartz, microcline, muscovite, and biotite, and locally garnet or sillimanite.
Metamorphic > SchistTrap Falls Formation (may be equivalent in part to Golden Hill Schist) - Gray to silvery, partly rusty weathering, medium-grained generally well layered schist, composed of quartz, sodic plagioclase, biotite, muscovite, and garnet, locally with sillimanite or kyanite. Ordovician? granitic gneiss (including local terms Ansonia, Mine Hill, "Tyler Lake," "Siscowit") - Commonly contains numerous inclusions or layers of mica schist.
Minor
Metamorphic > AmphiboliteTrap Falls Formation (may be equivalent in part to Golden Hill Schist)
Metamorphic > GranuliteTrap Falls Formation (may be equivalent in part to Golden Hill Schist)
Comments Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium; may be equivalent in part to Golden Hill Schist. Units are described seperately on printed map; combined in digital map.
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 Fairfield