Basal part of Cody shale

Basal part of Cody shale: gray and dark-gray shale with some sandstone beds; in north end of Big Horn Basin includes the Telegraph Creek formation.
State Montana
Name Basal part of Cody shale
Geologic age Phanerozoic | Mesozoic | Cretaceous-Late
Primary rock type shale
Secondary rock type sandstone
Other rock types
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Map references
Ross, P.R., Andrews, D.A., and Witkind, I.J., 1955, Geologic map of Montana: U.S. Geological Survey, 2 sheets, scale 1:500,000.
Unit references
Nichols, D.J. and Brown, J.L., 1992, Palynostratigraphy of the Tullock Member (lower Paleocene) of the Fort Union Formation in the Powder River basin, Montana and Wyoming, in Evolution of sedimentary basins--Powder River basin: U.S. Geological
Richards, P.W. and Rogers, C.P., Jr., 1951, Geology of the Hardin area, Big Horn and Yellowstone Counties, Montana: U.S. Geological Survey Oil and Gas Investigations Map OM-111, 2 sheets, scale 1:63,360 (Reprinted 1975).
Vuke, S.M., Wilde, E.M., Lopez, D.A., and Bergantino, R.N., 2000, Geologic map of the Lodge Grass 30' x 60' quadrangle, Montana: Montana Bureau of Mines and Geology Geologic Map 56, scale 1:100,000.
Vuke, S.M., Wilde, E.M., and Bergantino, R.N., 1999, Geologic map of the Hardin 30' x 60' quadrangle, eastern Montana, revised 1999: Montana Bureau of Mines and Geology Open File Report 392, 9 p., scale 1;100,000.
Richards, P.W., 1955, Geology of the Bighorn Canyon-Hardin area, Montana and Wyoming: U.S. Geological Survey Bulletin 1026, 96 p., (incl. geologic map, scale 1:62,500).
Counties Big Horn - Carbon