Frontier formation (MTKf;0)

State	Montana
Name	Frontier formation
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Late
Original map label	Kf
Primary rock type	medium-grained mixed clastic
Secondary rock type	bentonite
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Mixed-clastic (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] Rigby, J.K. and Rigby, J.K., Jr., 1990, Geology of the Sand Arroyo and Bug Creek quadrangles, McCone County, Montana: Brigham Young University Geology Studies, v. 36, p. 69-134. 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 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] 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. Merewether, E.A., 1996, Stratigraphy and tectonic implications of Upper Cretaceous rocks in the Powder River basin, northeastern Wyoming and southeastern Montana, in Evolution of sedimentary basins--Powder River basin: U.S. Geological Survey Bul [http://pubs.er.usgs.gov/publication/b1917T] 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. 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] 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. Tysdal, R.G., Dyman, T.S., Nichols, D.J. and Cobban, W.A., 1990, Correlation chart of Frontier Formation from Greenhorn Range, southwestern Montana, to Mount Everts in Yellowstone National Park, Wyoming: U.S. Geological Survey Miscellaneous Fiel [http://pubs.er.usgs.gov/publication/mf2116] Roberts, A.E., 1965, Correlation of Cretaceous and lower Tertiary rocks near Livingston, Montana with those in other areas in Montana and Wyoming, in Geological Survey research 1965: U.S. Geological Survey Professional Paper 525-B, p. B54-B63 [http://pubs.er.usgs.gov/publication/pp525B] Ruppel, E.T., 1972, Geology of pre-Tertiary rocks in the northern part of Yellowstone National Park, Wyoming, with a section on Tertiary laccoliths, sills, and stocks in and near the Gallatin Range, Yellowstone National Park, in Geology of Ye
Geographic coverage	Big Horn - Carbon - Yellowstone