730 THE ILLINOIS GLACIAL LOBE. 



The thickness of drift is known only at the village of Sullivan, where 

 it is about 200 feet. Borings in neighboring counties also penetrate nearly 

 as great an amount of drift. It therefore seems probable that the thickness 

 at Sullivan is not much above the average for the county. Wells in this 

 county enter a soft blue till at 10 or 15 feet, which, like that of the neigh- 

 boring counties, Piatt and Macon, belongs to the "Wisconsin drift. It prob- 

 ably extends to the level of the plain outside the Wisconsin drift sheet, 

 which is nearly 100 feet lower than the general elevation of this county. 

 Few records of wells were obtained, though it was ascertained that while 

 wells are usually but 30 or 40 feet deep, not a few are sunk to depths of 

 over 100 feet. 



INDIVIDUAL WELLS. 



At Sullivan the strongest wells are obtained at a depth of 100 to 125 

 feet in sand beds below till, and the waterworks are supplied from a well of 

 this class. A coal boring at or near Sullivan, made by Mr. John Patterson, 

 is reported to have struck a soft sandstone at about 200 feet, but a well 

 boring at Sullivan, made by Mr. Patterson, is reported in the Geology of 

 Illinois to have reached a depth of 210 feet without entering rock and to 

 have terminated in sand below clay. Veins of water were struck at 15 feet, 

 105 feet, and 180 feet. The last vein struck has a head 15 feet below the 

 surface. 



At Dalton there is a village well 110 feet in depth, which obtains its 

 main supply from about 70 feet. 1 Several wells in this vicinity are 70 

 to 85 feet in depth and a few about 100 feet. They reach the base of the 

 Wisconsin drift at about 65 feet, below which there is sandy material often 

 associated with a black mucky soil. Beneath this sandy material is a 

 harder till than the Wisconsin. The deepest wells in that vicinity are 

 150 feet, and none strike rock. 



At Bethany wells are often sunk to a depth of 70 feet before reaching 

 a good supply of water. The Wisconsin drift here is only about 40 feet, 

 beneath which there is a greenish clay associated with a black muck. This 

 is underlain by a hard till, in which there are gravelly beds yielding water. 

 The deepest wells are 140 feet and do not enter rock. 



1 The Manual of American Waterworks (1897) reports that the public water supply at Dalton 

 is obtained from a shallow well requiring a pump but 22 feet in length. This is evidently a mistake, 

 since no waterworks had been constructed or were contemplated at the time of my visit in June, 1897. 



