Permian, undifferentiated (MTPu;0)

State	Montana
Name	Permian, undifferentiated
Geologic age	Phanerozoic \| Paleozoic \| Permian
Original map label	Pu
Primary rock type	fine-grained mixed clastic
Secondary rock type	carbonate
Other rock types	chert; phosphorite; black shale; oil shale
Lithologic constituents	Major Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed) Sedimentary > Carbonate (Bed) Minor Sedimentary > Clastic > Mudstone > Shale > Oil-shale (Bed) Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed) Sedimentary > Chemical > Phosphorite (Bed) Sedimentary > Chemical > Chert (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	Van Gosen, B.S., Elliott, J.E., LaRock, E.J., du Bray, E.A., Carlson, R.R., and Zientek, M.L., 2000, Generalized geologic map of the Absaroka-Beartooth study area, south-central Montana: U.S. Geological Survey Miscellaneous Field Studies Map MF-2338, sca [http://pubs.er.usgs.gov/publication/mf2338] Ruppel, E.T., O'Neill, J.M., and Lopez, D.A., 1993, Geologic map of the Dillon 1o x 2o quadrangle, Idaho and Montana: U.S. Geological Survey Miscellaneous Investigations Series Map I-1803-H, scale 1:250,000. [http://pubs.er.usgs.gov/publication/i1803H] O'Neill, J.M., Christiansen, R.L., 2002, Geologic map of the Hebgen Lake quadrangle: Montana Bureau of Mines and Geology Open File Report 464, 21 p, scale 1:100,000. 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. Russel, C.W., 1991, Gold mineralization in the Little Rocky Mountains, Phillips County, Montana, in Baker, D.W., and Berg, R.B., eds., Guidebook of the Central Montana Alkalic Province--Geology, ore deposits and origin: Montana Bureau of Mines and Geolog 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). [http://pubs.er.usgs.gov/publication/b1026] 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. Blackstone, D.L., Jr., 1975, Geology of the East Pryor Mountain quadrangle, Carbon County, Montana: Montana Bureau of Mines and Geology Special Publication 69, 13 p., 1 plate, scale 1:24,000. Kellogg, K.S., and Williams, V.S., 2000, Geologic map of the Ennis 30' x 60' quadrangle, Madison and Gallatin Counties, Montana, Park County, Wyoming: U.S. Geological Survey Miscellaneous Geologic Investigations Series Map I-2690, scale 1:100,000. [http://pubs.er.usgs.gov/publication/i2690] Lonn, J., 2000, Geologic map of the Lima 30' x 60' quadrangle, southwest Montana: Montana Bureau of Mines and Geology Open File Report 408, 12 p., scale 1:100,000. Cressman, E.R., 1955, Physical stratigraphy of the Phosphoria Formation in part of southwestern Montana: U.S. Geological Survey Bulletin 1027-A, p. 1-31, 5 plates. [http://pubs.er.usgs.gov/publication/b1027A] Cressman, E.R., and Swanson, R.W., 1964, Stratigraphy and petrology of the Permian rocks of southwestern Montana: U.S. Geological Survey Professional Paper 313-C, p. 275-569, plates 14-25. [http://pubs.er.usgs.gov/publication/pp313C] McKelvey, V.E., and others, 1959, The Phosphoria, Park City, and Shedhorn Formations in the western phosphate field: U.S. Geological Survey Professional Paper 313-A, 47 p., 3 plates. [http://pubs.er.usgs.gov/publication/pp313A] Swanson, R.W., 1970, Mineral resources in Permian rocks of southwest Montana: U.S. Geological Survey Professional Paper 313-E, p. 661-777, plates 26-29. [http://pubs.er.usgs.gov/publication/pp313E] Witkind, I.J., Huff, L.C., Ridenour, James, Conyac, M.D., and McCulloch, R.B., 1981, Mineral resource potential of the Centennial Mountains Wilderness Study Area and contiguous areas, Idaho and Montana: U.S. Geological Survey Miscellaneous Field Studies [http://pubs.er.usgs.gov/publication/mf1342B]
Geographic coverage	Beaverhead - Big Horn - Carbon - Gallatin - Granite - Jefferson - Madison - Powell - Silver Bow - Stillwater - Sweet Grass