Hitherto, the writer's study of the drift of South Dakota has led him to consider it to belong mainly, if not entirely, to the Wisconsin epoch. The reasons briefly stated are as follows.
Proceedings of the Iowa Academy of Sciences
©1898 Iowa Academy of Science, Inc.
Todd, J. E.
"New Light on the Drift in South Dakota,"
Proceedings of the Iowa Academy of Science, 6(1), 122-130.
Available at: https://scholarworks.uni.edu/pias/vol6/iss1/22