wells of Mcdonough county, Illinois. 685 



Mcdonough county, 

 general statement. 



McDonough County is situated east of Hancock and has an area of 

 540 miles, with Macomb as the county seat. The county is drained almost 

 entirely by Crooked Creek, through several tributaries leading southwest- 

 ward to that stream. The surface is generally much eroded, but there is a 

 flat strip on the north and east borders in which drainage is rather imperfect. 

 The county is covered to a depth of 8 to 12 feet or more with a porous 

 sheet of loess which absorbs water rapidly and returns it to the crops in 

 seasons of drought. 



The drift is composed largely of a compact till, and in places strong 

 wells can not be obtained in it. Throughout much of the county, however, 

 the wells do not enter the rock. There is apparently a general coating of 

 50 to 75 feet of drift, and in places a much greater depth. In the extreme 

 northeast corner, however, near Prairie City, the rock rises in ridges slightly 

 above the general level of the upland plain. 



INDIVIDUAL WELLS. 



At Prairie City wells on the rock ridges are sunk to depths of 50 feet 

 or more ; those on the plane tracts obtain water in the drift at 20 to 30 feet. 



At Bushnell the public water supply is obtained from a well 115 

 feet in depth which does not enter rock. A well at the Toledo, Peoria and 

 Western Railway station enters rock at 140 feet. The drift consists of 

 about 20 feet of loess and yellow till, beneath which is a heavy sheet of 

 blue till. Wells are obtained from thin beds of sand and gravel in the blue 

 till, or occasionally at the top of the till. 



At Macomb the public water supply is obtained from a well 1,630 feet 

 in depth. The well is cased to the St. Peter sandstone, which is entered at 

 1,135 feet, and the entire supply is from that sandstone. An analysis made 

 by this Survey is published in the Seventeenth Annual Report (Part II, 

 pp. 925, 926). The water is moderately hard, but its chief mineral ingre- 

 dients are sodium chloride and sodium sulphate. Some dissatisfaction with 

 the use of the water is felt because of these ingredients, though the quality 

 is similar to that of the water from several other wells in use in western 

 Illinois. The drift at Macomb has a known range of nearly 100 feet in 



