564 THE ILLINOIS GLACIAL LOBE. 



In the other cities, and especially in the villages, private wells and cisterns 

 are used extensively. 



Turning to drift wells, it is found that 22 cities and villages, with a 

 combined population of about 100,000, obtain then public supply from 

 wells in glacial drift which have strong hydrostatic pressure, many of them 

 being flowing wells. In 38 other cities and villages, with a population 

 aggregating about 60,000, drift wells are in use which display no marked 

 hydrostatic pressure. There are only three cities with a population of more 

 than 2,000 in which this class of wells constitutes the public supply, namely, 

 Mattoon, Pana, and Paris. There are 9 cities and villages, with a combined 

 population of about 50,000, in which the public supply is obtained from 

 beds of alluvium. Among these cities Springfield has been included, its 

 supply being from infiltration wells along the bank of the Sangamon River. 

 The supply at Freeport is from wells sunk below the level of the Pecatonica 

 River, and these may possibly be referable to class 3 rather than to this 

 class. However, the material penetrated appears to be alluvial rather than 

 glacial. 



DETAILED DISCUSSION. 



With this brief statement concerning the sources for supply in the 

 cities of Illinois, we pass to the detailed discussion of wells by counties. 

 The counties are taken up in the order of their numbering on PL XX. 

 The discussion begins in the northern tier of counties and passes back and 

 forth in successive tiers, terminating at the southern end of the State. The 

 unglaciated counties at the southern end of the State are discussed as a 

 single district and very briefly, though they present probably a greater 

 variety of sources for water supply than almost any other area of equal 

 size within the State. The writer's examination of that district has been 

 too incomplete to enable him to treat adequately of its water resources. 



JO DAVIESS COUNTY. 

 GENERAL STATEMENT. 



This county is situated in the extreme northwest corner of the State and 

 has an area of 663 square miles. The greater part lies within the Driftless 

 Ai-ea, the glaciated portion occupying only about 100 square miles on the 

 eastern border. The driftless portion, however, is covered with a nearly 

 continuous sheet of loess, the thickness of which along the borders of the 



