Waterford Group and Branford Gneiss

Waterford Group (may be equivalent in part to Monson Gneiss) - Interlayered part (but layers locally distinct) of Waterford Group, light to dark, generally medium grained gneiss, composed of plagioclase, quartz, and biotite, with hornblende in some layers and microcline in others. Some layers of amphibolite. Branford Gneiss - Gray to white but rarely pink., medium-grained, well-foliated granitic gneiss, composed of oligoclase, K-feldspar, quartz, biotite, garnet, magnetite, and muscovite.
State Connecticut
Name Waterford Group and Branford Gneiss
Geologic age Proterozoic Z?
Lithologic constituents
Major
Metamorphic > GneissWaterford Group (may be equivalent in part to Monson Gneiss) - Interlayered part (but layers locally distinct) of Waterford Group, light to dark, generally medium grained gneiss, composed of plagioclase, quartz, and biotite, with hornblende in some layers and microcline in others. Branford Gneiss - Gray to white but rarely pink., medium-grained, well-foliated granitic gneiss, composed of oligoclase, K-feldspar, quartz, biotite, garnet, magnetite, and muscovite.
Minor
Metamorphic > AmphiboliteWaterford Group - some layers of amphibolite
Comments Part of Eastern Uplands; Avalonian (Continental) Terrane; Avalonian Anticlinorium; Branford Gneiss only = East Haven granitic body (may be equivalent to Sterling Plutonic-Group) (includes Light House Gneiss, Branford Gneiss, and Stony Creek Granite Gneiss) (Proterozoic Z?). Printed map has unit Zb by itself, digital map combines Zb with Zw.
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 New Haven