Pg. 17, 24-29. Basin shale. Marine shales, dark colored, containing calcareous concretions and many Niobrara fossils in upper half. The large brown sandy concretions at base are highly fossiliferous. There is at base a persistent conglomerate 2 feet thick. Thickness of formation 900 to 1,000 feet. Rests disconformably (erosion) on Torchlight sandstone member of Benton, and underlies Pierre shale, which is overlain by Eagle sandstone [Parkman sandstone]. [In Wyoming State Geol. Bull., no. 11, 1915, on Little Buffalo basin, Hintze gave thickness as 1,200 to 1,250 feet.] Age is Late Cretaceous.
[GNC remark (ca. 1936, US geologic names lexicon, USGS Bull. 896, p. 123): As above defined, this unit includes Carlile and Niobrara shales of present nomenclature, the overlying so-called Pierre shale of Hintze being the Steele shale of current nomenclature.]

Source: US geologic names lexicon (USGS Bull. 896, p. 123).