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Underhill Formation, White Brook Member

Underhill Formation, White Brook Member - Chiefly brown-weathered whitish, tan and gray sandy dolomite, locally only a hematitic zone; includes carbonaceous crystalline limestone in Cambridge syncline. (Northern and Central Vermont).
State Vermont
Name Underhill Formation, White Brook Member
Geologic age Cambrian
Comments Part of Green Mountains, Camels Hump Group The Underhill lies stratigraphically above basement rocks of Mount Holly Complex of Grenville (1 b.y.) age. Age changed to Late Proterozoic and(or) Early Cambrian (Slack and others, 1988) per VT020.
Primary rock type dolostone (dolomite)
Secondary rock type limestone
Other rock types
Lithologic constituents
Major
Sedimentary > Carbonate > DolostoneChiefly brown-weathered whitish, tan and gray sandy dolomite, locally only a hematitic zone.
Incidental
Sedimentary > Carbonate > LimestoneIncludes carbonaceous crystalline limestone in Cambridge syncline.
Map references
Nicholson, S.W., Dicken, C.L., Horton, J.D., Foose, M.P., Mueller, J.A.L., and Hon, Rudi, 2006, Preliminary integrated geologic map databases for the United States: Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, Rhode Island, and Vermont: U.S. Geological Survey Open-File Report 2006-1272.
Unit references
Doll, C.G., Cady, W.M., Thompson, J.B., Jr., and Billings, M.P., 1961, Centennial Geologic Map of Vermont: Vermont Geological Survey, Miscellaneous Map MISCMAP-01, scale 1:250,000.
Slack, J.F., Atelsek, P.H. and Grosz, A.E., 1988, Geology and geochemical survey of the Bristol Cliffs Wilderness, Addison County, Vermont: U.S. Geological Survey Miscellaneous Field Studies Map, MF-1593-A, 1 sheet, scale 1:24,000.
Counties Chittenden - Franklin - Lamoille