Amphibolite unit [in Ratlum Mountain Schist]

Black or mottled, generally massive amphibolite and hornblende gneiss, composed of hornblende and andesine, commonly with minor quartz and magnetite, and locally with garnet, biotite, and epidote.
State Connecticut
Name Amphibolite unit [in Ratlum Mountain Schist]
Geologic age Lower? Ordovician
Lithologic constituents
Major
Metamorphic > AmphiboliteBlack or mottled, generally massive amphibolite and hornblende gneiss, composed of hornblende and andesine, commonly with minor quartz and magnetite, and locally with garnet, biotite, and epidote.
Metamorphic > Gneiss > Hornblende-gneissBlack or mottled, generally massive amphibolite and hornblende gneiss, composed of hornblende and andesine, commonly with minor quartz and magnetite, and locally with garnet, biotite, and epidote.
Comments Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium; Hartland Belt. Equivalents of Savoy Schist of Massachusetts (Emerson, 1898, 1917) (CT009, CT010) and of Moretown Formation of Vermont and Massachusetts (Bedrock Geologic Map of Massachusetts, Zen and others, 1983) (CT011) (includes Golden Hill and Ratlum Mountain Schists) (Lower? Ordovician).
References
NGMDB product
Counties Fairfield - Litchfield