WELLS OF DEWITT COUNTY, ILLINOIS. 705 



part of the county is traversed by the outer moraine of the Wisconsin drift 

 sheet, which here has a relief of nearly 100 feet above the plain to the 

 west, but rises only a few feet above the plain to the east. 



The drift of this county, like that of the neighboring counties, Piatt 

 and McLean, is very heavy, averaging probably more than 200 feet. The 

 upper 100 feet is mainly a blue till, except on the plain outside the Wiscon- 

 sin drift, where much sand and gravel occurs. The few deep wells sunk on 

 the newer drift indicate that the sandy drift continues eastward under the 

 Wisconsin drift sheet. In several places buried soils, or muck beds, have 

 been found about the level of the base of the Wisconsin drift. There are 

 also numerous instances of inflammable gas from beds of sand and gravel 

 in the drift. 



INDIVIDUAL WELLS. 



But few records of wells have been obtained in this county, and these 

 are of considerable depth. Wells are often obtained at moderate depths in 

 sand or gravel associated with the blue till. 



At Farmer City the public water supply is from a well 176 feet in 

 depth, which terminates in sand. The head is now a few feet below the 

 surface, but when first made the well overflowed. A prospect boring for 

 coal at this town entered rock at a depth of 189 feet. The upper half of 

 the drift is mainly till, the lower half largely sand and gravel. (See section 

 on page 216.) 



A well one mile north of Parnell, 200 feet in depth, did not enter the 

 rock. 



At Clinton strong wells are obtained from sand and gravel below till 

 at depths of 80 to 110 feet. The public water supply is obtained from 

 several wells about 110 feet in depth. The following detailed record of the 

 drift penetrated at Clinton, in a prospect boring for coal, made with a 

 diamond drill, is taken from the Geology of Illinois: 1 



Drift beds in a prospect boring for coal at Clinton, Illinois. 



Feet. 



Surface soil .' 5 



Quicksand 15 



Sand with gravel and bowlders 17 



Sand and clay mixed 53 



Hardpan 12 



Gravel 1 



Hardpan 4 



'Vol. VIII, p. 34. 

 MON XXXVIII 45 



