WELLS OP ADAMS COUNTY, ILLINOIS. 713 



loess is usually but 10 or 15 feet. On the borders of the Illinois, however, 

 it attains in one place a thickness of over 100 feet, a large part of the bluff 

 being formed of that deposit, The Illinois bottoms occupy an average 

 width of about two miles along the east border of the county, and the 

 higher portions of the bottoms are sandy and gravelly, but the lower por- 

 tions are covered with a deposit of muck. 



Although the drift is comparatively thin throughout much of the 

 county, wells are usually obtained without entering the rock. The rock 

 consists largely of a sandy shale, which often affords water in fair amount. 



INDIVIDUAL WELLS. 



At Mount Sterling the wells are usually obtained from sandy clay at 

 depths of 16 to 25 feet. The Manual of American Waterworks states that 

 the public supply is from an open well. 



In the vicinity of Mount Sterling shale is often struck at about 25 

 feet. The Illinoian drift embraces only about half this depth, there being 

 10 or 12 feet of loess at the surface. 



In the vicinity of Versailles wells are often sunk to a depth of 50 feet, 

 and they are largely through loess. 



At Mound Station, in the northwest part of the county, a well at the 

 lumber yard enters rock at 44 feet. The mounds or low hills immediately 

 northwest of this station, which give it "its name, are said to have a nucleus 

 of rock which causes their relief of 50 feet or more above the plain. 



ADAMS COUNTY. 

 GENERAL STATEMENT. 



Adams County borders the Mississippi River in the western part of the 

 State, with Quincy as the county seat, and has an area of 830 square miles. 

 The northern third of the county is drained westward through Bear Creek, 

 the southwestern part is drained westward through Mill Creek, and the 

 southeastern part is drained eastward through McKee's Creek, a tributary 

 of the Illinois River. In the western, central, and southern portions of the 

 county there are several ridges of drift formed near the western border of 

 the Illinoian drift sheet and trending in a general northwest-southeast direc- 

 tion. These ridges are each a mile or less in average width and rise 20 

 to 50 feet above the bordering plains. Their distribution is shown on the 



