Two Medicine formation (MTKtm;0)

State	Montana
Name	Two Medicine formation
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Late
Original map label	Ktm
Primary rock type	clastic
Secondary rock type	volcanic rock (aphanitic)
Other rock types	limestone; bentonite
Lithologic constituents	Major Sedimentary > Clastic > Mudstone (Bed) Sedimentary > Clastic > Sandstone (Bed) Minor Sedimentary > Carbonate > Limestone (Bed) Igneous > Volcanic (Pyroclastic) Incidental 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	Berg, R.B., Lonn, J.D., 1999, The preliminary geologic map of the Nez Perce Pass 30' x 60' quadrangle, Montana, revised 1999: Montana Bureau of Mines and Geology Open File Report 339, 14 p., scale 1:100,000. Viele, G.W. and Harris, F.G., III, 1965, Montana Group stratigraphy, Lewis and Clark County, Montana: American Association of Petroleum Geologists Bulletin, v. 49, no. 4, p. 379-417. Stebinger, E., 1914, Titaniferous magnetite beds on the Blackfeet Indian Reservation, Montana: U.S. Geological Survey Bulletin 540, p. 329-337. [http://pubs.er.usgs.gov/publication/b540] Schmidt, R.G., 1972, Geologic map of the Coburn Mountain quadrangle, Lewis and Clark and Cascade Counties, Montana: U.S. Geological Survey Geologic Quadrangle Map GQ-975, 1 sheet, scale 1:24,000. [http://pubs.er.usgs.gov/publication/gq975] Gill, J.R. and Cobban, W.A., 1973, Stratigraphy and geologic history of Montana Group and equivalent rocks, Montana, Wyoming, and North and South Dakota: U.S. Geological Survey Professional Paper 776, 37 p. [http://pubs.er.usgs.gov/publication/pp776]
Geographic coverage	Cascade - Glacier - Lewis and Clark - Pondera - Teton - Toole