V4 CHICAGO ACADEMY OF SCIENCES. 



There seems no escape from the conchision that the lake stood at 

 a lower stage than the level of the second beach before that beach 

 and the bar under discussion were formed. 



The Third or ToUeston Beach — This beach receives its name 

 from the village of Tolleston, situated in Northwestern Indiana at 

 the crossing- of the Pittsburg, Ft. Wayne and Chicago Railway and 

 the Michigan Central Railway, 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, and it becomes a matter of no small difficulty to determine 

 what beaches should be included with this lake stage. There are, 

 by actual count, 32 beachlets crossed on a N.-S. line about three 

 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 considered 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 further on, seem to have been formed after the 

 southeastward outlet was abandoned. This being the case they 

 should not be referred to Lake Chicago. 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 cut ter- 

 race. In Cook County this beach appears 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 

 no well-defined beach appears on the west side of the bay back of 

 it. This bar lies within a mile of the present shore of Lake Michi- 

 gan and is readily traced as far south as Lincoln Park. The bar 

 is said to have been nearly continuous through the city of Chicago, 

 but it is now obliterated from Lincoln Park southward nearly to 

 the Douglas Monument, and I have been unable to obtain a map 



