LAKE CHICAGO AND ITS OLD SHORE LINES 83 



level of the lake was held at this point for a long period. During 

 this time the waves and currents made such inroads on the shore 

 and such extensive deposits that we trace them today in a series 

 of beaches and sand bars that are referred to this Calumet stage 

 (Fig. 51). The course of the Calumet beach can be traced on 

 the map (Fig. 53). The old Desplaines Bay was now dry land, 



/ \ 



FIG. 51. Lake Chicago at a later stage (the Calumet) and Lake Warren. 

 A tremendous volume of water must have been going through the outlet past the 

 present site of Chicago. After Leverett and Taylor. 



and the river emptied into the lake near the present site of 

 Lyons. Salt Creek flowed in at the same point. Evidently in 

 the lake during the Glenwood stage a great sand bar had formed 

 in the lea of Blue Island and a smaller one out in the south channel 

 of the outlet. These now appear, the former as a portion of the 

 large island that included Mount Forest Island and Blue Island, 

 the latter as a separate islet, Lanes Island. Note the long sand 



