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Narragansett Bay Group - Purgatory Conglomerate

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Buff to pale-gray conglomerate. Clasts consist entirely of quartzite; matrix primarily quartz, plus sparse amounts of magnetite. Cobbles and boulders are ubiquitously elongate, due to pressure-solution phenomena associated with deformation.
State Rhode Island
Name Narragansett Bay Group - Purgatory Conglomerate
Geologic age Pennsylvanian
Lithologic constituents
Major
Sedimentary > Clastic > ConglomerateBuff to pale-gray conglomerate. Clasts consist entirely of quartzite; matrix primarily quartz, plus sparse amounts of magnetite.
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.
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.
NGMDB product
Counties Newport