Skip to main content

Middlebury and Chazy Limestone; Undifferentiated Youngman and Carman Formations

Middlebury and Chazy Limestone, Undifferentiated Youngman and Carman Formations - Dark blue-gray, somewhat nodular and granular limestone with buff dolomite and shaly interbeds a fraction of an inch thick and 2 to 4 inches apart. The Middlebury, which is east of Champlain and Orwell thrusts, and the Youngman, which is east of Highgate Springs thrust, are, due partly to deformation, more slaty in appearance than the Chazy, which is west of the major thrusts. The Carman is a quartz sandstone with shaly partings that underlies the Youngman. The Chazy contains 3 members.
State Vermont
Name Middlebury and Chazy Limestone; Undifferentiated Youngman and Carman Formations
Geologic age Ordovician
Comments Part of Champlain and Vermont Valleys, Chazy Group
Primary rock type limestone
Secondary rock type dolostone (dolomite)
Other rock types shale; sandstone
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)dark blue-gray, somewhat nodular and granular limestone
Incidental
Sedimentary > Carbonate > Dolostone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Sandstone (Bed)The Carman is a quartz sandstone with shaly partings that underlies the Youngman.
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.
Counties Addison - Franklin - Rutland