Summary of StratigraphyThe classification and nomenclature of the rock units described in this report have been adopted by the State Geological Survey of Kansas. They differ somewhat from the usage adopted by the U.S. Geological Survey.
The rocks that crop out in Sumner County are sedimentary in origin and range in age from Paleozoic to Recent (Pl. 1). The oldest rocks are a part of the Wellington Formation of the Leonardian Stage, Permian System. The Wellington Formation forms the bedrock surface in approximately the eastern two-thirds of the county and crops out in local areas where it is not covered by Pleistocene deposits. The Ninnescah Shale, also of the Leonardian Stage, forms the bedrock surface in approximately the western third of the county and crops out in local areas where it is not covered by Pleistocene deposits.
Cenozoic deposits of the Pleistocene Series representing four glacial stages and possibly the interglacial stages occur in Sumner County. Deposits of Nebraskan-Aftonian age underlie the surface in the northwestern part of the county near Conway Springs. Deposits of Kansan-Yarmouthian age are most extensive in the eastern and southern parts of the county. Illinoisan-Sangamonian and Wisconsinan terrace deposits border most of the major streams of the county, and Recent deposits form the flood plains and occur also as sand dunes. Deposits of the interglacial stages were not recognized, however, and therefore in this report the deposits referred to a glacial stage include those of the subsequent interglacial stage if present. Deposits of Kansan and Illinoisan age are mapped together on Plate 1.
A generalized section of the rocks that crop out in Sumner County is given in Table 3.
Table 3--Generalized section of rocks* that crop out in Sumner County and their water-bearing characteristics.
Kansas Geological Survey, Sumner County Geohydrology|
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Web version January 2003. Original publication date August 1961.