Bearpaw shale (MTKb;0)

State	Montana
Name	Bearpaw shale
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Late
Original map label	Kb
Primary rock type	shale
Secondary rock type	sandstone
Other rock types	bentonite
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale (Bed) Minor Sedimentary > Clastic > Mudstone > Claystone > Bentonite (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	Lewis, R.S., 1998, Preliminary geologic map of the Butte 1° x 2° quadrangle: Montana Bureau of Mines and Geology Open File Report 363, 16 p, scale 1:250,000. Stebinger, E., 1914, The Montana group of northwestern Montana: U.S. Geological Survey Professional Paper 90, p. 62-68. [http://pubs.er.usgs.gov/publication/pp90] Obradovich, J.D. and Cobban, W.A., 1975, A time-scale for the Late Cretaceous of the Western Interior of North America, in Caldwell, W.G., ed., The Cretaceous System in the Western Interior of North America: Geological Association of Canada S Skipp, Betty and McGrew, L.W., 1977, The Maudlow and Sedan Formations of the Upper Cretaceous Livingston Group at the west edge of the Crazy Mountains basin, Montana, in Contributions to stratigraphy: U.S. Geological Survey Bulletin 1422-B, p. [http://pubs.er.usgs.gov/publication/b1422B] Knechtel, M.M. and Patterson, S.H., 1956, Bentonite deposits in marine Cretaceous formations, Hardin district, Montana and Wyoming: U.S. Geological Survey Bulletin 1023, 116 p. [http://pubs.er.usgs.gov/publication/b1023] 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). [http://pubs.er.usgs.gov/publication/om111]
Geographic coverage	Big Horn - Blaine - Carbon - Chouteau - Fergus - Garfield - Glacier - Golden Valley - Hill - McCone - Meagher - Musselshell - Petroleum - Phillips - Pondera - Richland - Roosevelt - Rosebud - Stillwater - Sweet Grass - Treasure - Valley - Wheatland - Yellowstone