WELLS OF COOK COUNTY, ILLINOIS. 589 



but within 2 miles west of Maywood rock is struck at about 30 feet. The 

 Manual of American Waterworks (1897) reports that the public supply is 

 from an artesian well. A well in the Des Plaines valley near the Twelfth 

 street bridge does not reach rock. 



At Riverside the water supply is obtained from artesian wells about 

 2,200 feet in depth, which reach the Potsdam sandstone. The supply is 

 partly from the St. Peter and other strata above the Potsdam. The wells 

 originally overflowed, but the head is now 20 feet below the surface, or 

 about 600 feet above tide. With a diameter of but 3£ inches, the capacity 

 of one of these wells is estimated to be more than one million gallons per 

 day. 



At Lagrange the public supply is from artesian wells, but no data were 

 obtained concerning their depths and capacities. In the east part of the 

 village a flowing well is obtained from the drift at a depth of 21 feet. Rock 

 outcrops within the limit of this village at a higher elevation than the mouth 

 of this well. On the plain east of Lagrange rock is frequently struck at 

 about 20 feet. The drift there is mainly a blue clay, there being only 5 or 

 6 feet of yellow clay at surface. In some cases sand and gravel occur just 

 above the rock. West of Lagrange, in the vicinity of Western Springs, 

 wells often reach a depth of 40 or 50 feet without entering rock. 



Borings in the vicinity of Summit show the depth to rock to range from 

 10 feet or less to fully 40 feet. The beach gravel in the south part & of the 

 village is shown by a gravel pit to have a depth of 20 feet. Beneath this 

 gravel is blue till. On the plain southeast from Summit several wells are 

 sunk 45 to 55 feet without reaching rock. 



At Washington Heights a well at Klein's Hotel enters rock at 70 feet, 

 penetrating the following beds: 



. Section of well at a hotel in Washington Heights. 



Gravel Feet - 



Yellow till 3 



Blue till • "" 5 



Limestone 



3 



Other wells are obtained in that vicinity at shallower depths. The 

 public water supply is from a deep well. 1 



A well at Morgan Park, on the crest of the Blue Island till ridge, 1,046 

 feet in depth, has a head 594 feet above tide. Limestone is entered 'at a 



1 Manual of American Waterworks. 



