Immediately following the time that the Altamont moraine was formed there was an intermittent retreat of the Wisconsin ice sheet to the position of the Gary (?) about fifty miles north-northwest of Des Moines. In Story County the distance between these moraines decreases to about thirty miles and northward from Story county it becomes as small as twenty miles in some places.
Proceedings of the Iowa Academy of Science
© Copyright 1929 by the Iowa Academy of Science, Inc.
Smith, John E.
"Recessional Stages Between the Altamont and the Gary (?) Moraines in Iowa,"
Proceedings of the Iowa Academy of Science, 36(1), 278-279.
Available at: https://scholarworks.uni.edu/pias/vol36/iss1/69