From abstract: Reconnaissance examination of widely scattered outcrops of Upper Cretaceous rocks in the heavily glaciated areas of eastern North Dakota provides the basis for the first formal subdivision of the Pierre Shale in these areas.

From abstract and introduction: Mineralogic and stratigraphic studies of the lower part of the Pierre Shale of Late Cretaceous age along the Missouri River indicate correlations different from those generally accepted. The purposes of this paper are to present evidence for the new correlations and to resolve problems of formal nomenclature that result from them.