572 THE ILLINOIS GLACIAL LOBE. 



Table of well sections east of Bock River in Winnebago County, Illinois — Continued. 



The waterworks station at Rockford is located near the base of the 

 west bluff of Rock River Valley in the north part of the city. Five wells 

 are sunk to the Potsdam sandstone, from which water rises barely to the 

 siu-face (719 feet above tide). "With a diameter of 6 inches, each well fur- 

 nishes about 200 gallons per minute by pumping. The drift ranges from 

 125 to 190 feet in depth. The upper portion is sand and gravel, but the 

 lower portion is largely blue clay. No wells have been sunk in the midst 

 of the valley at Rockford of sufficient depth to reach the rock. The distance 

 to rock is probably much greater than in the wells at the waterworks. 1 



At Pecatonica wells usually obtain water in the limestone at depths of 

 80 to 125 feet. The drift in that vicinity is but a few feet in depth. The 

 waterworks is supplied from springs. 



In the vicinity of Winnebago Village the distance to rock ranges from 

 20 to at least 80 feet. Wells are usually obtained without entering rock, 

 though several have been sunk some distance into the rock. 



In the vicinity of Elida the drift is usually about 50 feet, and a few 

 wells pass into the underlying limestone. West from Elida and also north- 

 west, over an area of perhaps 50 square miles, wells usually obtain water in 

 the rock at depths ranging from 40 to 100 feet. The drift in that locality is 

 thin, seldom exceeding 20 feet. Mr. Buell, however, reports two wells in 

 sec. 3, T. 26, R. 10 E., 50 and 60 feet in depth, which do not strike rock. 

 Another well in the same section enters rock at 40 feet and is carried to a 

 depth of 110 feet. Still another well located on a drift knoll enters rock at 



'The data from Rockford have been lurnished by Daniel W. Mead, C. E., of that city. 



