Named in Medicine Bow Mountains, WY as formation (fourth from base of six formations) in Deep Lake Group (raised in rank). Source of name not stated. Type section designated and measured at NW1/4 sec 4, T16N, R80W, Carbon Co, in the Northern Rocky Mountain region. Divided into basal light-gray to white medium-grained quartz, locally trough cross-bedded arenite 437 ft thick, middle 2,400-ft-thick pyritic, pebbly quartz arenite, and subarkose, and an upper 1,919-ft-thick pink, highly feldspathic, coarse-grained, pebbly arkosic to subarkosic quartzite. Pebbles in middle unit are of well-rounded, moderately well sorted quartz and black chert as much as 3 cm in diameter. Pyrite in middle unit occurs as sparse euhedral grains less than 1 mm in diameter. Matrix in upper unit contains orthoclase, microcline, and plagioclase. Pebbles in upper unit are well-rounded vein quartz and granite? as much as 1 cm in diameter; average 5 mm. Of glacial? and marine origin. Overlies Campbell Lake Formation (new) of Deep Lake; lower contact is gradational, being placed above highest gray, laminated phyllitic quartzite of Campbell Lake. Overlain unconformably by Vagner Formation (new). Geologic map; stratigraphic charts. Early Proterozoic age.

Source: GNU records (USGS DDS-6; Denver GNULEX).

In the Medicine Bow Mountains, WY, Northern Rocky Mountain region, Cascade: assigned as the fourth formation from base of five formations of the Deep Lake Group of the newly defined Snowy Pass Supergroup; unconformably overlies Campbell Lake Formation and unconformably underlies Vagner Formation, both of Deep Lake. In the Sierra Madre, Cascade: assigned to the lower part of the Snowy Pass Group; unconformably overlies Singer Peak Formation of the lower part of the Snowy Pass and unconformably underlies Bottle Creek Formation (new) of Snowy Pass. Is 600-850 m thick in Medicine Bows and 500-1,500 m thick in the Sierra Madre. Geologic map; correlation chart. Of Early Proterozoic age.

Source: GNU records (USGS DDS-6; Denver GNULEX).