From abstract: The northern Black Hills bentonite mining district includes parts of Crook County, Wyo., Carter County, Mont., and Butte County, S. Dak. Within this district, many beds of bentonite occur interspersed with sedimentary strata of Cretaceous age that have an average total thickness of about 3,000 feet and consist chiefly of marine shale, marl, and argillaceous sandstone. The bentonite beds occur in formations ranging upward from the Newcastle sandstone to the lower part of the Mitten black shale member of the Pierre shale. Tertiary (?) and Quaternary deposits of gravel, sand, and silt are present on extensive terraces, and deposits of such materials also extend along stream courses in all parts of the district.

From introduction: Geologic mapping of the Carlile quadrangle, which includes one of several uranium-producing areas in northeastern Wyoming, was undertaken to provide a detailed geologic map that could be used as an aid to further exploration for uranium deposits; to study in detail the known uranium deposits to determine whether or not there are any relations among structure, stratigraphy, lithology, and uranium deposits; and to outline, insofar as possible, areas favorable for more detailed exploration for uranium.