Previous investigations in Pleistocene geology in Iowa have resulted in the development of the concepts of gumbotil and the flat gumbotil plains of the Nebraskan and Kansan drift sheets. During recent field work in southwestern Iowa the writer noted differences in textures of the materials of the weathered zones of these tills. Measurable differences in altitudes of the tops of these materials were also noted. Field evidence indicates that (1) the term gumbotil cannot be used to describe all types of weathered till, and (2) variations in relief exist on the surface of the weathered zones of the Nebraskan and Kansan drift sheets.
Proceedings of the Iowa Academy of Science
©1948 Iowa Academy of Science, Inc.
Ruhe, R. V.
"Some Notes on the Pleistocene Geology of Shelby County, Iowa,"
Proceedings of the Iowa Academy of Science, 55(1), 281-290.
Available at: https://scholarworks.uni.edu/pias/vol55/iss1/38