Washington, DC: United States Geological Survey/USGS/Government Printing Office/GPO, 1972. Softcover. Item #46751
Stratigraphic and mineralogic study of one of the more distinctive and widespread shale units of Late Cretaceous age in the western interior of the United States. 50 pages with maps, sections, photographs, tables, bibliography and index, plus the two plates bound in the rear. Bound in original stiff gray paper printed in black. Library receiving stamp on the front cover. No other library markings, plates or pockets were ever present. A near fine copy.