Collins Hill Formation (CTOch;0)

Collins Hill Formation

( = Partridge Formation of New Hampshire) - Gray, rusty-weathering, medium- to coarse-grained, poorly layered schist, composed of quartz, oligoclase, muscovite, biotite, and garnet, and commonly staurolite, kyanite, or sillimanite, generally graphitic, interlayered with fine-grained two-mica gneiss, especially to the west, and with calc-silicate and amphibolite layers, also rare quartz-spessartine (coticule) layers.

State	Connecticut
Name	Collins Hill Formation
Geologic age	Upper? and Middle Ordovician
Lithologic constituents	Major Metamorphic > SchistGray, rusty-weathering, medium- to coarse-grained, poorly layered schist, composed of quartz, oligoclase, muscovite, biotite, and garnet, and commonly staurolite, kyanite, or sillimanite, generally graphitic. Minor Metamorphic > Gneissinterlayered with fine-grained two-mica gneiss, especially to the west Incidental Metamorphic > Metasedimentary > Calc-silicate-rockcalc-silicate and rare quartz-spessartine (coticule) layers Metamorphic > Amphibolite
Comments	Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Bronson Hill Anticlinorium; Brimfield Schist and equivalent formations (includes Collins Hill Formation) (Upper? and Middle Ordovician).
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	NGMDB product page for 54245
Counties	Hartford - Middlesex - New Haven - Tolland

Collins Hill Formation

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