FACTORS 



45 



/ SHEET /J /-. ~vt:o; 



ICE SHEET 



THE HISTORY OF THE CHICAGO REGION 



FIG. i. Showing the region of the Great Lakes when the Wisconsin ice sheet 

 was retreating from its maximum extent (after Atwood and Goldthwait). 



FIG. 2. A part of the same area, showing the drainage of the ice sheet by the 

 Kankakee and Huron rivers through Dowagiac Lake (from Lane after Leverett). 



FIG. 3. Showing a later stage of the retreat of the ice sheet the Glen wood 

 stage (from Lane after Leverett). 



FIG. 4. A later stage of the same the Calumet stage of Lake Chicago (from 

 Goldthwait after Leverett and Taylor). 



FIG. 5. A still later stage probably the Tolleston stage (from Lane after 

 Leverett). 



FIG. 6. A post-Tolleston stage (from Goldthwait and Atwood after Leverett 

 and Taylor). 



