THE CEERO GOEDO MORAINE. 219 



stands only 10 to 15 feet above the border plain. The ridge is nearly 

 continuous except at the Embarras River, which cuts through it opposite 

 Dora Station. In Edgar County the belt has, on the whole, a stronger 

 expression, though there is not so continuous a ridge as in Douglas and 

 Coles counties. There are several small ridges, one-fourth mile or less in 

 width and 10 to 20 feet in height, which form a disjointed chain leading 

 southeastward from Brocton to Paris. Associated with these there are 

 knolls of considerable prominence. A cluster in sees. 15, 16, and 17, T. 14, 

 R. 12 W., known as the Blue Mounds, rise 50 or 60 feet above the border 

 plains. An isolated knoll in sec, 32, T. 15, R. 13 W., is about 50 feet in 

 height and occupies perhaps 20 acres. North and northwest from this 

 knoll, in sees. 29 and 30, several knolls rise abruptly to a height of 20 or 

 30 feet, and one to a height of 40 feet. In the northeast part of Paris there 

 is a ridge leading from Sugar Creek southwestward about 1J miles, which 

 is 30 to 50 feet in height and has a billowy surface. Its width is 40 to 60 

 rods. Probably this ridge belongs in the belt under discussion, though it 

 is slightly out of line with the belt and is separated from it hj a plane tract 

 about 2 miles in width. Toward the northeast there are occasional knolls 

 as far as the State line, but no definite ridge or chain of knolls appears. 

 The well-defined belt terminates at the Blue Mounds. 



STRUCTURE OP THE DRIFT. 



Some of the sharper knolls of the moraine contain gravel and sand, 

 especially along the border of the Sangamon River and in Edgar County. 

 There is, as a rule, considerable till associated with the gravel and sand, 

 and the knolls are usually underlain by a sheet of till. The gentle 

 swells and the smooth ridges are composed more largely of till than those 

 of sharper contour. 



The majority of wells along this belt obtain their supply at a level 

 little, if any, below the base of the knolls and ridges and within the limits 

 of the early Wisconsin drift sheets. A few pass into the older drift. Very 

 rarely a well reaches the rock. The drift, as in the tract outside the moraine, 

 is very thick in Illinois except in the vicinity of the State line, but is thin 

 in Indiana. The following are the deepest wells of which records were 

 obtained: 



On H. H. Hollis's farm, in sec. 30, T. 20, R. 7 E., a well is 215 feet in 



