246 THE ILLINOIS GLACIAL LOBE. 



between the Illinois and Mackinaw rivers in Tazewell and Woodford coun- 

 ties. The fifth section (50 to 55 miles) embraces the portion between the 

 Mackinaw River and the reentrant angle in Ford County. The sixth sec- 

 tion (nearly 100 miles) embraces the portion between the reentrant angle 

 in Ford County, Illinois, and points where this system passes beneath the 

 moraines of late Wisconsin age in Benton and Warren counties, Indiana. 

 For the distribution of the several sections see PI. VI. 



Between western Kane County and the head of Bureau Creek. TllC Section betwedl WeSt- 



ern Kane County, Illinois, and the head of Bureau Creek, taken as a whole, 

 consists of a mass of drift standing 50 to 100 feet or more above the plains 

 on the northwest and southeast borders, and occupying a width of 6 to 15 

 miles. Much of, the surface is nearly plane, and differs but little from that 

 of the plain on the southeast. There is, however, scarcely a square mile in 

 which knolls 10 to 20 feet high are not present, and also shallow basins 

 which contain ponds. The decidedly morainic expression is confined to 

 three somewhat narrow belts, one on the outer border, another on the inner 

 border, and an intermediate less definite belt 



The belt on the outer border leads from Hampshire westward into 

 Dekalb County, crossing South Kishwaukee River just above the bend near 

 Genoa, and then curves around to the soiithwest and south in western De- 

 kalb and southeastern Ogle and eastern Lee counties. Its width is seldom 

 more than 3 miles, and in places scarcely reaches 2 miles. From Hamp- 

 shire west to the Kishwaukee River it is less prominently ridged than west 

 of that stream, there being a rise of scarcely 50 feet to its highest points 

 from the plain on the north. This portion, however, has about as much 

 morainic expression as the higher part of the border to the west. Knolls 

 10 to 25 feet are closely aggregated and inclose shallow basins. The basins 

 are usually depressed but 5 or 6 feet below the lowest part of their rims, and 

 occupy only an acre or two. Occasionally a basin occupying as much as 10 

 acres is to be seen. From South Kishwaukee River southwestward through 

 western Dekalb and southeastern Ogle counties, the outer belt consists of a 

 series of narrow ridges with shallow sags between them, each trending with 

 the entire belt in a NE.-SW. course, changing to southward in Ogle County. 

 The ridges are each a mile or less in width and stand 30 to 50 feet above 

 the intervening sags. There are in places four ridges, but usually only two 

 or three. Each ridge has gentle undulations on its crest and slope, seldom 



