MUCH OF THE MIDWEST HAS FEATURES FORMED BY SEDIMENT TRANSPORTED BY GLACIERS

 

MANY FORMED BETWEEN ABOUT 25,000 AND 14,000 YRS AGO DURING THE LAST ICE AGE'S FINAL (WISCONSIN) EPISODE, WHEN A VAST SHEET OF ICE FORMED OVER CANADA. GLACIERS FLOWED AWAY FROM THE CENTER OF THE ICE SHEET. THE GLACIER THAT FLOWED THROUGH THE LAKE MICHIGAN BASIN AND INTO NE ILLINOIS REACHED ITS SOUTHERNMOST EXTENT ABOUT 20,000 YEARS AGO

(Illinois State Geological Survey)