Widespread deposits of sand and rubble extend throughout the entire valley of Kankakee River, from its headwaters in northwestern Indiana to its confluence with Des Plaines River in northeastern Illinois. The complex origin of these deposits has been gradually unfolded as new data on the conditions of glacial drainage have been obtained. Most writers have associated all or part of these deposits with some sort of lake, but the character and geological relations of such a lake have never been definitely or satisfactorily determined. The present study is a contribution to the solution of the complex problem and suggests lines of further investigation.
Probably the first geologic recognition of these deposits was incidentally recorded by Shepard,2 who asserted that evidence of the occasional overflow of Lake Michigan at ancient periods exists along the Kankakee Valley. Later investigations have proved that this view of the relation with Lake Michigan is . . .