In the great southern flow of ice, two streams, one coming through Iowa and the other through Illinois, apparently merged their forces in the valley of the Mississippi. This union extended from somewhere near where Clinton now stands to about the present site of St. Louis. It is not at all likely that the ice streams first met at the northern point indicated; for the center of the movement on the Illinois side was well over towards the eastern part of the state, and likewise the center of the Iowa lobe was a goodly distance away from the Mississippi. From these centers the advancing fronts deployed to the right and left, thus producing movements diverging from the central axis.
Proceedings of the Iowa Academy of Sciences
©1894 Iowa Academy of Science, Inc.
Fultz, Francis M.
"Extension of the Illinois Lobe of the Great Ice Sheet into Iowa,"
Proceedings of the Iowa Academy of Science, 2(1), 209-212.
Available at: https://scholarworks.uni.edu/pias/vol2/iss1/44