584 THE ILLINOIS GLACIAL LOBE. 



years. The first well was sunk in 1864 in the northwest part of the city, 

 on the highest ground then within the city limits, and at an altitude of 31 feet 

 above Lake Michigan, the precise location being at the corner of Chicago 

 and Western avenues. This well was sunk by a band of Spiritualists with 

 a view to prospecting for petroleum, and it is reported that the site of the 

 well was determined by Mr. James, a so-called medium, while entranced. 

 Only a small amount of oil was found, but at a depth of 711 feet a strong 

 flow of water was struck, which rose to a height of 80 feet above the 

 surface, or 111 feet above Lake Michigan. A second well only a few feet 

 distant was sunk the following year, which obtained a flow of water at a 

 depth of 694 feet. The history of these wells is set forth in an interesting 

 manner in a pamphlet entitled "Histoiy of the Chicago artesian well," 

 by George A. Shufeldt, jr., issued by the Religio-Philosophical Publishing 

 Association of Chicago in 1867. Mr. W. T. B. Read, who drilled the wells, 

 still resides in the city. 1 He reports that the head has decreased to such an 

 amount that the water now stands 15 or 20 feet below the surface, or nearly 

 100 feet below its original head, and that the wells are not in use. These 

 wells apparently obtained their supply of water from the Galena limestone, 

 the depth being insufficient to touch the St. Peter sandstone. 



Within a few years after the drilling' of the wells just noted, several 

 deeper ones were sunk in the city and strong flows were obtained. The 

 earlier ones usually reached the St. Peter sandstone, but it is probable that 

 much of their supply came from higher strata. At the present time there 

 are several hundred wells within the city used by the various industries 

 which demand large quantities of water. A large part of them penetrate 

 only to the St. Peter sandstone, but many enter the underlying limestone 

 and not a few reach the Potsdam sandstone. The deepest ones are about 

 2,700 feet. At this depth water is much more saline than in the St. Peter 

 sandstone or Galena limestone. The disadvantage resulting from salinity 

 will probably restrict the boring of wells in the future to depths of not more 

 than 2,500 feet. The boring of so many wells within a limited area has 

 led to such an excessive drain upon the rock strata that the head is kept 

 below the normal, and an overflow is now rarely obtained. 



The deepest drift encountered in Cook County, so far as known to the 

 writer, is in a well at Samuel Church's, near the center of the northwest 



1 At 95(1 W(st Cbioajto avenue. 



