At the last meeting of the Academy I called attention to an extension of the Wisconsin drift south, past Valley Junction into the region which was generally understood to be within the area of Kansan drift. It was with a view to extending observations further south in that direction than was possible in the time previously at my disposal that trips were made in 1914 extending the area examined east to the Army Post, west to the ravines in the southwest portion of Polk county, and, as far south as Norwalk, Cummings and Orillia in Warren county and west to Madison county.
Proceedings of the Iowa Academy of Science
©1915 Iowa Academy of Science, Inc.
Tilton, John L.
"The Extension of the Wisconsin Drift Southwest from Des Moines,"
Proceedings of the Iowa Academy of Science, 22(1), 229-232.
Available at: https://scholarworks.uni.edu/pias/vol22/iss1/28