WELLS OF COLES COUNTY, ILLINOIS. 735 



The Wisconsin drift sheet in this count}-, as in neighboring counties 

 already discussed, consists largely of a soft blue till, while the underlying- 

 sheet of drift is a harder till. Along the Embarras River there are expos- 

 ures of the harder till beneath the Wisconsin drift, and this harder till is 

 capped by a white clay, as in the districts outside the limits of the 

 Wisconsin drift. 



In the eastern portion of the county rock is occasionally entered at 45 

 to 50 feet, and is exposed extensively along the Embarras River in the 

 southern part of the county. The thickness in the western half of the 

 county is greater, being in places not less than 150 feet. Wells are usually 

 obtained without entering the rock, and in the western part of the county 

 but few reach the bottom of the Wisconsin sheet of drift. 



INDIVIDUAL WELLS. 



At Oakland, in the northeast part of the county/ the wells are usually 

 about 20 feet in depth. But a well at the mill reached a depth of 120 feet, 

 entering rock at 50 feet. 



Northwest from Fairgrange several wells have been sunk to depths of 

 60 to 120 feet without entering rock. They usually pass from a .soft to a 

 hard till at a depth of 50 or 60 feet. This is thought to be the depth of 

 the Wisconsin drift sheet in that locality. 



At Charleston the waterworks are supplied by pumping from the 

 Embarras River. Wells are usually obtained from sand and gravel below 

 till at a depth of 20 to 40 feet. A well in the northern part of this cit} T 

 reached a depth of 127 feet without entering rock, but a boring for oil 

 made some years since is reported in the Geology of Illinois to enter rock 

 at 55 feet. The section of drift is as follows : 



Section of boring at Charleston, Illinois. 



Feet. 



Soil and yellow clay lg 



Sand and gravel g 



Blue clay jg 



Bowlder clay 15 



Total drift 55 



At Mattoon the public water supply is obtained from sand and gravel 

 below till at a depth of 60 to 70 feet. The private wells in this village are 

 usually obtained at 15 to 30 feet. A coal boring is reported to enter rock 

 at about 100 feet (see p. 202). 



