THE GLACIAL LAKE CHICAGO. 447 



part of the basin these lakes extended beyond the present shore. As the 

 deep channeling of the valleys is continued well into the north half of 

 the basin, it may prove to be independent of the supposed Algonquin and 

 Nipissing lake levels in that region. 



THE THIRD OR TOLLESTON BEACH 



This beach received its name from the village of Tolleston, situated in 

 northwestern Indiana at the crossing of the Pittsburg, Fort Wayne and 

 Chicago and the Michigan Central railways, at a point immediately south 

 of the extreme head of Lake Michigan, and distant only 2£ miles from the 

 head of the lake. It is more complex than either of the higher beaches. 

 Indeed, it is a matter of no small difficulty to determine' what beachlets 

 should be included with this lake stage. There are, by actual count, 32 

 beachlets crossed on a north-south line about 3 miles east of the State line 

 of Illinois and Indiana. The outer line of this series is usually much 

 stronger than the others and stands a few feet higher, and hence is consid- 

 ered the main line. The village of Tolleston and also Hessville and Miller 

 Station, in Indiana, are situated on the outermost or main line. 



Many of the beachlets situated between the main line and the shore of 

 Lake Michigan stand only 10 to 12 feet above that lake, and, as shown 

 farther on, seem to have been formed after the southwestward outlet was 

 abandoned. This being the case, they may not be referable to Lake Chi- 

 cago. The Third or Tolleston beach, as here described, includes only such 

 beaches and bars as have sufficient elevation above the sill of the Chicago 

 Outlet to indicate that they are connected with that outlet — beaches whose 

 elevation is 18 to 25 feet above the level of Lake Michigan. 



The portion of the shore of this lake stage in Lake County, Illinois, 

 is closely associated with that of the higher lake stages and consists of a 

 gravelly deposit flanking the foot of the old lake bluff. In Cook County 

 this beach appears at the lake bluff on the grounds of the Northwestern 

 University, in Evanston, and for several miles south it lies near the east 

 border of the bar formed at the next preceding lake stage. From Rose 

 Hill Cemetery southward it is beyond the limits of the bar, but is perhaps 

 itself a bar built out southward into a bay now traversed by Chicago 

 River. It appears to have reached some distance south at an early part of 

 this lake stage, for only a poorly defined beach appears on the west side of 



