Mowry shale (MTKmo;0)

State	Montana
Name	Mowry shale
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Early
Original map label	Kmo
Comments	As used on this map, "Mowry shale" is only applied to rocks in the northern Bighorn basin. Mowry Shale is now applied to several other portions of Montana. Many of the rocks shown as Kc on the map include the Mowry shale.
Primary rock type	fine-grained mixed clastic
Secondary rock type	bentonite
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed) Minor Sedimentary > Clastic > Mudstone > Claystone > Bentonite (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	Roberts, A.E., 1972, Cretaceous and early Tertiary depositional and tectonic history of the Livingston area, southwestern Montana, in Geology of the Livingston area, southwestern Montana: U.S. Geological Survey Professional Paper 526-C, p. C1 [http://pubs.er.usgs.gov/publication/pp526C] Ruppel, E.T., 1998, Geologic map of the eastern part of the Leadore 30' x 60' quadrangle, Montana and Idaho: Montana Bureau of Mines and Geology Open File Report 372, 9 p., scale 1:100,000. Lopez, D.A., 2000, Geologic map of the Billings 30' x 60' quadrangle, Montana: Montana Bureau of Mines and Geology Geologic Map 59, scale 1:100,000. Fraser, G.D., Waldrop, H.A. and Hyden, H.J., 1969, Geology of the Gardiner area, Park County, Montana: U.S. Geological Survey Bulletin 1277, 118 p. [http://pubs.er.usgs.gov/publication/b1277] Cobban, W.A., 1951, Colorado shale of central and northwestern Montana and equivalent rocks of the Black Hills: American Association of Petroleum Geologists Bulletin, v. 35, no. 10, p. 2170-2198. Rubey, W.W., 1931, Lithologic studies of fine-grained Upper Cretaceous sedimentary rocks of the Black Hills region, IN Shorter contributions to general geology, 1930: U.S. Geological Survey Professional Paper 165-A, p. A1-A54. [http://pubs.er.usgs.gov/publication/pp165A] 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. Tysdal, R.G., Dyman, T.S. and Nichols, D.J., 1989, Correlation chart of Lower Cretaceous rocks, Madison Range to Lima Peaks area, southwestern Montana: U.S. Geological Survey Miscellaneous Field Studies Map MF-2067, 15 p., 1 sheet. [http://pubs.er.usgs.gov/publication/mf2067] Lopez, D.A., 2000, Geologic map of the Bridger 30' x 60' quadrangle, Montana: Montana Bureau of Mines and Geology Geologic Map 58, scale 1:100,000.
Geographic coverage	Big Horn - Carbon - Carter - Yellowstone