First published use for a sandstone, unranked and one of five named unranked sandstones in the Mesaverde formation, exposed as a cliff around north and east banks of Rocky Ridge Reservoir, Larimer Co, CO in the Denver basin. Also forms a cliff outlining Douglas Mesa. Is 97 ft thick. [No lithologic description given.] Overlies and underlies unnamed shale of the Mesaverde. Cretaceous age.

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

Recognized as one of five sandstones reassigned as a member of Pierre shale rather than as an unranked unit of the Mesaverde formation. Separated from older Terry sandstone member of Pierre by 300 to 600 ft of sandy shale, and from younger Larimer sandstone member of the Pierre by about 175 ft of sandy shale. Consists of a lower shaly sandstone and an upper gray, massive, cross-bedded, calcareous sandstone with many iron concretions. The upper sandstone weathers to hoodoos and is very fossiliferous (INOCERAMUS). Is 123 ft thick in a measured section on Fossil Creek near Fort Collins. Is usually 50 to 100 ft thick. Does not have a distinct base or top at many localities. Geologic map. Not separately mapped from Pierre. Pierre forms extensive outcrops in Larimer, Morgan, and Washington Cos, CO in the Denver basin. Of Late Cretaceous age.

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

Correlation of Upper Cretaceous Pierre Shale (and its Hygiene, Terry, Rocky Ridge, and Larimer Sandstone Members) near Boulder, CO in Denver basin with Pierre Shale (and its Sharon Springs, Kemmling, Muddy Buttes, Hygiene, Carter and Gunsight Pass Members) near Kremmling, CO, and with the upper part of Mancos Shale (and its Morapos and Loyd Sandstone Members) and with Iles Formation (and its Tow Creek and Trout Creek Sandstone Members) and Williams Fork Formation (and its Twentymile Sandstone Member); the last two are formations of Mesaverde Group shown on fig. 2.

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

Geographically extended northward into WY along the Laramie Mountains. Replaces use of Parkman Sandstone Member in Denver basin. Recognized at Francis Ranch on the outcrop in Ts14 and 15N, R69W, Laramie Co, WY, and in the subsurface in Apache Co., 1 Polo Ranch in sec 14, T14N, R66W, Laramie Co, WY. Is a member of Pierre Shale 226.1 ft thick composed of light-gray to dark-orange, very fine to medium grained, cross-bedded, friable sandstone with large brown-weathering calcareous sandstone concretions. Abundant Ophiomorpha. Separated from the younger Larimer Sandstone Member by 90 ft of covered interval. Underlain by an unnamed sequence of Pierre. Stratigraphic chart; measured section. Campanian age.

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