722 IHE ILLINOIS GLACIAL LOBE. 



are over 100 feet in height. But in portions of the county the drift is only 

 2<) or 3<» feet in depth. The drift filling is sufficient to greatly conceal the 

 courses of preglacial tributaries of the Illinois. Till forms the principal 

 part of the drift, though in some parts of the county wells pass through a 

 large amount of gravel and sand. The wells are usually 20 to 40 feet in 

 depth and obtain water from the drift, very seldom entering the rock. 



INDIVIDUAL WELLS. 



In the vicinity of Winchester wells are usually obtained at a depth of 

 20 or 30 feet, but a well at the grist mill was sunk to a depth of 412 feet. 

 It has a head 60 feet below the surface, or 470 feet above tide. 



In the vicinity of Manchester wells are obtained at a depth of 20 or 30 

 feet. A coal shaft enters rock at about 60 feet. 



In the vicinity of Alsey wells are obtained at about 40 feet. They 

 penetrate 8 or 10 feet of loess, and then pass through till to the water- 

 bearing bed at bottom. 



Near Glasgow, on the Illinois River bluff, wells usually pass through 

 about 25 feet of loess, 20 feet of yellow till, and 30 feet or more of blue 

 till before entering rock. In some cases they are obtained above the rock. 



MORGAN COUNTY. 

 GENERAL STATEMENT. 



Morgan County is situated north and east of Scott County and touches 

 the Illinois River for a few miles on its northwest border. It has an area of 

 580 square miles, and Jacksonville is the county seat. It is drained west- 

 ward to the Illinois River through several creeks, of which Indian and 

 Mauvaise Terre creeks are the largest. Like Scott County, this county has 

 a heavy coating of loess on the border of the Illinois River, but only a thin 

 deposit a few miles back from the Illinois The loess and drainage lines, as 

 in Scott County, give excellent drainage. 



The drift is thin in the southeast portion of the county, rock being at 

 depths of but 20 or 30 feet in many of the wells, but in the remainder of 

 the county the thickness generally exceeds 50 feet and in places reaches 

 at least 150 feet. It consists largely. of till, but gravel and sand beds are 

 sufficiently abundant to supply water for most of the wells. The wells are 

 seldom sunk to depths of more than 40 or 50 feet. 



