LAKE CHICAGO AND ITS OLD SHORE LINES 



79 



at a level some sixty feet above the present lake level (581 feet 

 above sea- level) . It is by following these plainly marked beaches 

 that the position of the shore lines of early Lake Chicago is 

 determined (Fig. 49). On the map (Fig. 53, page 85), can be 

 traced the shore line of what is known as the Glenwood stage of 



FIG. 48. The Wisconsin ice sheet at its maximum. Border of ice represented 

 by heavy feathered line. 



Lake Chicago (Fig. 50), so named because the beaches are par- 

 ticularly conspicuous at Glenwood near the Industrial School 

 (Chicago & Eastern Illinois Railroad). Northwest from this 

 point the old beach runs to the north of Homewood (on the 

 Illinois Central Railroad) about a mile southwest of Rexford 

 (on the Rock Island) to the north of Palos Springs (Wabash). 

 It is plainly seen on the east side of Mount Forest Island (driv- 

 ing west on Ninety-fifth Street) or in approaching the island from 

 Summit on the Chicago and Joliet interurban. At McCook 



