Lamprophyre

Dark-gray to greenish, fine-grained, badly altered dike rock, composed of biotite, augite, K-feldspar, and accessory apatite and sphene, plus secondary minerals.
State Connecticut
Name Lamprophyre
Geologic age Devonian?
Lithologic constituents
Major
Igneous > Hypabyssal > Lamprophyre (Dike or sill)Dark-gray to greenish, fine-grained, badly altered dike rock, composed of biotite, augite, K-feldspar, and accessory apatite and sphene, plus secondary minerals.
Comments Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium
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