Named as basal member of South Platte formation of Dakota group for exposures in the cut of the Denver and Salt Lake RR through the Dakota hogback at Plainview, NE1/4 NE1/4 sec 12, T2S, R71W, Jefferson Co, CO in Denver basin. No type section designated, though a section measured at location above. Is a light gray, fine-, medium- to coarse-grained sandstone which has some cross laminated to cross-bedded units. Basal sandstone is conglomeratic. Is interbedded with dark gray to black shale which has local thin concretionary lenses of pyritic silt and gray argillaceous thin-bedded siltstone. Is 56+/-ft at measured section. Has a maximum thickness of 65 ft. Disconformably overlies Lytle formation of Dakota group. Underlies an unnamed shale and sandstone of the South Platte. Has a nonmarine phase in the south and a marine phase in the north. Correlation with other Cretaceous units in Powder River basin northeast WY, Wind River basin central WY, and Denver basin southeast WY, northeast and south-central CO shown on fig 19. Is of Early Cretaceous age.

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

Shown on "Correlation chart" as one of four formations of Lower Cretaceous Dakota Group, as unconformably overlying Lytle Formation of Dakota and as beneath Skull Creek Shale (extended from south-central WY) into northern Front Range foothills, from Loveland to Boxelder Creek (sec 9, T10N, R69W), Larimer Co, CO in the Denver basin. [No discussion of modification of stratigraphic rank change.] Correlation chart.

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