304 THE ILLINOIS GLACIAL LOBE. 



that it is a spur from the reentrant angle in the Bloomington system need 

 not be set aside. 



The Kaneville esker lies mainly within the limits of this undulatory 

 belt and seems to have been formed at as late a date. Its western end, 

 together with the delta, extends beyond the line of the bowlder}' tracts 

 referred to the late Wisconsin invasion. This fact seems to throw the bal- 

 ance of evidence in favor of the correlation with the Bloomington system. 

 Furthermore, the Kaneville esker seems to be a part of the series of gravelly 

 knolls and ridges above mentioned which are developed along- the inner 

 border of the Bloomington morainic system in the district to the west. It 

 is possible that chains of gravelly knolls and ridg'es which lead westward 

 from Fox River Valley in northern Kane County into the higher portions 

 of the moraine were formed at the same time as this esker and under similar 

 conditions. The prominent knolls which occur in the midst of the gently 

 undulating belt — Johnson's Mound, Ball Mound, and Washburn's Mound — 

 may also be included in the same category. They appear to be composed 

 largely of gravel, though their structure is known only from two well sec- 

 tions on their higher parts and slight excavations on their borders. 



PORTION OF COMPOSITE BELT EAST OF FOX RIVER. 

 DISTRIBUTION AND CONNECTIONS. 



From the vicinity of Elgin northward to the Wisconsin line the valley 

 of Fox River alone separates a morainic tract on the east from one on the 

 west side of the river, and throughout much of this interval the stream winds 

 about through lakes and marshes among morainic knolls without forming a 

 well-defined valley. Southward from Elgin the composite belt separates 

 into distinct moraines, between which are plane tracts. One of these 

 moraines, called the Valparaiso, swings around the head of Lake Michigan ; 

 another, called the Marseilles, follows nearly the east bluff of Fox River 

 south and west to the Illinois River. As already noted, a weak morainic 

 system of late Wisconsin age leads southward, and the Bloomington system 

 southwestward, from the portion of the composite belt west of Fox River. 



The equivalency of the Valparaiso morainic system to the eastern 

 portion of this composite belt is established beyond doubt Probably it 

 should include all of the composite belt north of Elgin on the east side of 





