|Name||Narragansett Bay Group - Wamsutta Formation|
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.|
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/