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Dighton Conglomerate

Dighton Conglomerate - Coarse conglomerate having sandy matrix; minor sandstone. Dighton Conglomerate occurs in Narragansett basin. Consists of gray conglomerate composed mainly of rounded quartzite cobbles to boulders containing subordinate rounded granite cobbles and slate pebbles; very little sand matrix; lenses of medium-grained sandstone form less than 20 percent of unit. Age is Pennsylvanian (Goldsmith, 1991).
State Massachusetts
Name Dighton Conglomerate
Geologic age Upper Pennsylvanian
Comments Part of Milford-Dedham Zone (Tertiary and Older Rocks) Secondary unit description per MA023.
Primary rock type conglomerate
Secondary rock type sandstone
Other rock types
Lithologic constituents
Major
Sedimentary > Clastic > ConglomerateCoarse conglomerate having sandy matrix.
Minor
Sedimentary > Clastic > Sandstone
Map references
Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.
Unit references
Zen, E-An (ed.), Goldsmith, R. (comp.), Ratcliffe, N.M. (comp.), Robinson, P. (comp.), Stanley, R.S. (comp.), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.
Goldsmith, Richard, 1991, Stratigraphy of the Milford-Dedham zone, eastern Massachusetts; an Avalonian terrane, Chapter E, IN Hatch, N.L., Jr., ed., The bedrock geology of Massachusetts: U.S. Geological Survey Professional Paper, 1366-E-J, p. E1-E62.
Counties Bristol