Non-Lignite Marker Beds in the Sentinel Butte formation, McKenzie and Dunn Counties, North Dakota

Non-lignite marker beds in the Sentinel Butte Formation have been noted by several authors (Fisher, 1953; Meldahl, 1956; Clark, 1966; Royse, 1970; Cherven, 1973; Johnson, 1973). Five non-lignite marker beds listed by Royse (1970): 1) basal sand bed, 2) blue bed, 3) lower yellow bed, 4) upper yellow bed, and 5) upper sand bed. These are shown in Figure 1. The purpose of this study was to map the blue bed, the lower yellow bed, and the upper yellow bed, to determine their stratigraphic position, and to record the characteristics of the three beds