|Name||Ordovician? granitic gneiss|
|Geologic age||Middle Ordovician?|
Metamorphic > GneissWhite, light-gray, buff, or pink, generally foliated granitic gneiss, composed of sodic plagioclase, quartz, microcline, muscovite, and biotite, and locally garnet or sillimanite.
Metamorphic > Schist > Mica-schistCommonly contains numerous inclusions or layers of mica schist.
|Comments||Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium; including local terms Ansonia, Mine Hill, "Tyler Lake," "Siscowit" . Same as Og|
Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.