Portland Arkose

Reddish-brown to maroon micaceous arkose and siltstone and red to black fissile silty shale. Grades eastward into coarse conglomerate (fanglomerate).
State Connecticut
Name Portland Arkose
Geologic age Lower Jurassic
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone > Arkosereddish-brown to maroon micaceous arkose
Sedimentary > Clastic > Siltstone
Minor
Sedimentary > Clastic > ConglomerateGrades eastward into coarse conglomerate (fanglomerate).
Sedimentary > Clastic > Mudstone > Shalered to black fissile silty shale
Comments Part of Central Lowlands; Newark Terrane - Hartford and Pomperaug Mesozoic Basins. Part of Newark Supergroup (Upper Triassic and Lower Jurassic)
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 Hartford - Litchfield - Middlesex - New Haven - Tolland