Mesozoic EraDeposition evidently was terminated by an uplift that brought the region above water at the close of the Paleozoic. Probably this condition extended through the latter part, if not all, of Triassic time and through Jurassic time, during which there was no deposition and probably considerable erosion. Rocks representing the Triassic and Jurassic are not known to occur in Ford County.
Following an early Cretaceous uplift there was at first a land surface followed by a shallow-water body in Comanche time during which were deposited the sandstone and shale of the Cheyenne sandstone. The deposits were laid down either by streams or in a shallow sea or perhaps they were deposited in part on a beach, suggesting that the place of deposition was not far above or far from a shore line (Twenhofel, 1924, pp. 19-21).
Following this there was a change from continental to marine conditions as a result of submergence of the land surface during which time the Kiowa shale was deposited. The Cheyenne sandstone and the Kiowa shale both have been encountered in test drilling in Ford County and are known to underlie at least part of the county.
In Late Cretaceous time there was a return to conditions similar to those under which the Cheyenne sandstone and sands and clays of the Dakota formation were laid down. The Dakota formation is a fresh-water deposit that was laid down on beaches and near the shore during an uplift in which the sea retreated far to the south. The Dakota formation crops out at several places in the northern and northeastern parts of the county, and is present at varying depths elsewhere in the county.
Following the deposition of the Dakota formation there was a rapid change in the conditions of sedimentation to those under which several thousand feet of clay, lime, and chalk were deposited, begin-fling with the Graneros shale and including the Greenhorn limestone, the Carlile shale, the Niobrara formation, and the Pierre shale. This marks the beginning of very extensive later Cretaceous submergence, in which marine conditions prevailed over a large area for a long time. Sedimentation was interrupted from time to time by emergence of the land to a point at or near sea level.
Kansas Geological Survey, Ford Geohydrology|
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Web version April 2002. Original publication date Dec. 1942.