258 THE ILLINOIS GLACIAL LOBE. 



bowlders, whose distribution in belts was long since noted by members of 

 the Indiana survey. These belts of knolls and bowlders cross the ridges 

 and intervening plains of the Bloomington system nearly at right angles in 

 a NNW.-SSE. course, as may be seen by reference to the glacial map 

 (PI. VI). They assume greater strength a few miles to the north, there 

 being a prominent morainic belt in northwestern Benton and eastern 

 Iroquois counties, near the border of Illinois and Indiana. In this connec- 

 tion it may be remarked that the outer moraine of the late Wisconsin 

 system is very variable in strength from place to place, and has a develop- 

 ment about as weak in its passage across the Bloomington morainic system 

 ;ts in any part of its course. 



The weak moraine in eastern Iroquois County, Illinois. Of the Weak mOrailieS COIllieCted 



with the Bloomington system the first to receive consideration is the one 

 which emerges from beneath the late Wisconsin series near the Illinois- 

 Indiana line and passes westward into Iroquois County. This is main- 

 tained as a distinct ridge, 20 to 40 feet in height and scarcely more than a 

 mile in width, for a distance of about 8 miles west from the State line, 

 where it dies away on the border of Sugar Creek. It has a gently undu- 

 lating surface, the swells seldom exceeding 10 feet in height. The probable 

 continuation of this ridge is found in a poorly defined, undulatory belt which 

 appears on the west side of Sugar Creek opposite the end of this ridge and 

 leads westward to Onarga. It stands scarcely 20 feet above the bordering 

 plains on either side and its surface is but little more undulatory than that 

 of the plains. Its slight relief, however, is a matter of considerable conse- 

 quence, since it stands too high for flowing wells to be obtained, while the 

 neighboring plains furnish a large number of flowing wells from the drift. 

 This belt does not connect definitely with the bulky ridges at the west, but 

 as it is separated from them by a space of only 3 or 4 miles it seems to fall 

 naturally into the same system. 



cropsey Ridge. — From the west side of the reentrant angle in southeastern 

 Livingston County a small ridge leads westward, as already noted, past 

 Cropsey, across northern McLean County, forming a divide between the 

 Mackinaw and Illinois-Vermilion drainage basins. The portion east from 

 Cropsey stands 30 to 50 feet above the plain on the south, and in places 

 presents a very abrupt relief on that border. Toward the north it has a 



