One of the largest streams of the Missouri slope in Iowa, and one of much importance in its influence on topography is Boyer River. This streams takes its rise in the Kansan uplands south of Storm Lake, flows a little east of south across Sac county past the town of Wall Lake where it turns abruptly southwest. In this direction it crosses Crawford County, which it divides into practically equal parts. In its course across Crawford county Boyer valley is of the normal mature type but in southern Sac there opens into the valley from the northeast a broad sag which extends southwestward from Wall Lake. Digitate alluvial plains also extend several miles up the valley of the Boyer above the mouth of this sag and up the valleys of two tributaries from the eastern flank of the high ridge east of Odebolt. The flat undrained sag, although it is two or three times as wide as Boyer valley at Herring or Boyer, is nevertheless a direct continuation of it. On the other hand the present course of Boyer River north of the sag is out of line and out of harmony with the valley below.
Proceedings of the Iowa Academy of Science
©1919 Iowa Academy of Science, Inc.
Lees, James H.
"The History of Boyer Valley,"
Proceedings of the Iowa Academy of Science, 26(1), 493-500.
Available at: https://scholarworks.uni.edu/pias/vol26/iss1/48