Narragansett Bay Group - Wamsutta Formation (RIPAnbw;0)

Narragansett Bay Group - Wamsutta Formation

Red sandstone, shale, and conglomerate, locally containing abundant volcanic detritus as clasts and matrix. Plant fossil localities occur in adjacent Massachusetts. Minor, but significant amounts of interstratified bimodal-composition volcanic lava flows consisting of alkalic basalt (locally pillowed) and rhyolite are present in adjacent Massachusetts.

State	Rhode Island
Name	Narragansett Bay Group - Wamsutta Formation
Geologic age	Pennsylvanian
Lithologic constituents	Major Sedimentary > Clastic > Sandstone Sedimentary > Clastic > Mudstone > Shale Sedimentary > Clastic > Conglomerate
Comments	Part of Esmond-Dedham Subterrane. Narragansett Bay Group - deposited upon older rocks of both West Bay and East Bay parts of the Esmond-Dedham subterrane. Secondary unit description from USGS Geologic Names lexicon (ref. RI013): Wamsutta described as interbedded red, coarse-grained conglomerate, some felsite, lithic graywacke, sandstone, and shale. Contains a few lenses of limestone and one flow of red rhyolite and several sheets of altered mafic volcanics. Thickness is 595 m.
References	Hermes, O.D. (comp.), Gromet, L.P. (comp.), Murray, D.P. (comp.), Hamidzada, N.A., Skehan, J.W., and Mosher, S., 1994, Bedrock geologic map of Rhode Island: Rhode Island Map Series No. 1, Kingston, Rhode Island, scale 1:100,000. USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/ https://ngmdb.usgs.gov/Geolex/search
NGMDB product	NGMDB product page for 19719
Counties	Providence

Narragansett Bay Group - Wamsutta Formation

Hermes, O.D. (comp.), Gromet, L.P. (comp.), Murray, D.P. (comp.), Hamidzada, N.A., Skehan, J.W., and Mosher, S., 1994, Bedrock geologic map of Rhode Island: Rhode Island Map Series No. 1, Kingston, Rhode Island, scale 1:100,000.

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/