Relations of the Wisconsin and Kansan Drift Sheets in Central Iowa and Related Phenomena, 1897

(1897) Relations of the Wisconsin and Kansan Drift Sheets in Central Iowa and Related Phenomena, 1897. University of Iowa

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Abstract

The area which bas been studied in the preparation of the following memoir lies in central Iowa and includes Marshall, Story, Boone, Greene, Guthrie, Dallas, Polk and Jasper counties and a portion of Carroll. Its geographic features are represented upon the accompanying map (plate xxvii) and its relations to the state as a whole, are shown upon plate xxvi. It is an area of prairie plain with moderate relief, the altitude varying from 810 to 1,042. The country rock of the region includes both the Des Moines and Missourian divisions of the Upper Carboniferous and the Dakota formation of the Cretaceous. The distribution of these beds may be seen upon the geological map of the state published by the Iowa Survey and the details of the geology may be learned from the county reports issued by the same organization. t It is intended here to treat only of certain specific problems connected with two of the drift sheets of the region; for fuller details the reader is referred to the reports just cited, and particularly to the author's reports upon Polk and Guthrie counties. In the following paper no attempt will be made to cite the portions of each of these reports which bear out individual statements since the number of such citations would be so great as to to become cumbersome. The author's particular studies have been in Polk and Guthrie counties, in which be has mapped in detail the surface formations. These counties lie on the southern and southwestern border of the Des Moines lobe, and within their borders the relations herein discussed were first made out. The remaining portions of the area have been repeatedly visited, at times in company with other members of the Survey, and the results obtained in Polk and Guthrie counties have thus been compared with the phenomena in various portions of the larger area.