Abstract The outcrops of the Dakota Group and the Graneros Shalenental sandstones. As the viewer examines younger rocks toward Greenhorn Limestone interval of LateCretaceus age at Ponca the northwest, the original environments of deposition change, State Park provide an excellent sedimentary record of the last and these deposits give way to lagoonal, estuarine, or tidal and great marine invasion of the North American midcontinent. The mudflat deposits, which are finally overwhelmed by marine southeastern end of the outcrop area consists of the older continental sandstones. As the viewer examines younger rocks toward. the northwest, the original environments of deposition change, and these deposits give way to lagoonal, estuarine, or tidal and mudflat deposits, which are finally overwhelmed by marine shales and limestones.

Abstract Excellent outcrops of Niobrara and Pleistocene strata can be seen near Franklin and Bloomington (Exposures 1 and 2, Fig. 1; Figs. 2-5) in Franklin County. The Niobrara Formation generally dips westward at about 15 ft/mi (3 m/km), and at the western end of the outcrop area in Harlan County, the Niobrara is conformably overlain by the Pierre Shale. All of the outcrops are road cuts and are within public access. The outcrop near Franklin has a very steepnorth slope and a fairly gentle east slope. The section at the Bloomington bridge is very steep but negotiable by persons without physical limitations. The outcrops near Red Cloud are fairly steep but are also negotiable by persons without physical limitations.