|Name||Quartzite unit [in Plainfield Formation] plus Stony Creek Granite Gneiss plus Narragansett Pier Granite|
|Geologic age||Proterozoic Z? and Permian|
Igneous > Plutonic > Granitic > GraniteNarragansett Pier Granite - Pink to red, medium- to coarse-grained (commonly pegmatitic), generally massive (not gneissic) granite, composed of microcline, oligoclase, quartz, and biotite, and accessory muscovite and magnetite.
Metamorphic > Metasedimentary > Metaclastic > QuartziteQuartzite unit [in Plainfield Formation] - light-gray, glassy, generally thin bedded quartzite, also feldspathic and micaceous quartzite containing quartz-sillimanite nodules.
Metamorphic > GneissStony Creek Granite Gneiss - Red to pink, unevenly medium to very coarse grained, variably foliated granite or granite gneiss, composed of oligoclase, K-feldspar, and quartz with minor biotite and magnetite, sporatic garnet (in foliated varieties), and local muscovite.
Igneous > Plutonic > Granitic > Leucocratic-granitic > PegmatiteNarragansett Pier Granite - Considerable associated pegmatite.
|Comments||Part of Eastern Uplands; Avalonian (Continental) Terrane. Units are described seperately on printed map; combined in digital map.|
Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.