576 THE ILLINOIS GLACIAL LOBE. 



INDIVIDUAL WELLS. 



The northwestern township of the county (Chemung) is occupied 

 chiefly by a gravel plain, in which wells are obtained at a depth of 25 to 35 

 feet. In the vicinity of Chemung, however, the wells encounter till, and 

 their depth ranges from 20 feet to 70 or more, water being obtained in beds 

 of gravel associated with the till. 



The railway well at Harvard, in the southeast part of Chemung Town- 

 ship, is sunk to a depth of 900 feet, and is thought to terminate in the lower 

 portion of the St. Peter sandstone. The following strata were penetrated : 



Section of the railway well at Harvard, Illinois. 



Feet. 



Yellow and blue till 36 



Gravel and bowlders 24 



Sand and loose gravel 15 



Coarse gravel - 15 



"Hardpan" 12 



Limestone 108 



Shale - 85 



Mainly limestone 345 



Mainly sandstone 240 



The water is hard and is apparently largely derived from the limestone. 

 It rises within 41 feet of the surface, or to an altitude 894 feet above tide. 

 The well is cased only to the rock (102 feet), and has a diameter of 7 inches 

 below the casing. The capacity is estimated at 90 gallons per minute. 

 Many private wells are obtained in Harvard at a depth of about 25 feet. 

 The west part of the village is on a gravel plain, with a sheet of water at 

 20 to 25 feet or less. The railway station and east part of the village stand 

 on the slope of a moraine. 



In the township east of Chemung only one well record was obtained — 

 that at the cheese factory in the village of Alden. This well reached a depth 

 of 150 feet without entering rock, and has the following section: 



Section of well at a cheese factory in Alden, Illinois. 



Feet. 



Gravel and sand 15 



Blue till 100 



Black soil 2 



Till of bluish color 33 



It is probable that the soil struck at the base of the blue till marks 

 either the junction between the Wisconsin drift sheet and the Iowan, or 

 between the Iowan and Illinoian. The well is on a moraine. 



