WELLS OF MADISON COUNTY, ILLINOIS. 749 



western part of the county offers a medium for ready transmission of 

 impurities. 



INDIVIDUAL WELLS. 



At Godfrey, in the northwest part of the county, a deep well has 

 recently been sunk to the St. Peter sandstone and this supplies the Monti- 

 cello Seminary. Wells at the railway station reach a depth of about 30 

 feet without entering rock. 



At Alton the public water supply is pumped from the Mississippi River. 

 Wells on the uplands in the north part of the city penetrate 30 to 40 feet 

 of drift, and frequently obtain water without entering the rock. 



At Upper Alton the wells on the upland are usually obtained at 30 to 

 40 feet, near the base of the drift. The loess in this village has a thickness 

 of 20 feet or more, but is underlain by typical till, exposures of which may 

 be seen near Wyman Institute. The village contemplates putting in water- 

 works, which will be supplied from wells in the Mississippi Valley. 



In the vicinity of Fosterburg, in the northern part of the county, wells 

 are obtained at about 25 feet. The loess in that locality is only about 8 

 feet in depth. 



At Edwardsville the wells range in depth from 20 to 80 feet, the 

 shallower ones being obtained just below the loess, while the deeper ones 

 pass through a large amount of till and enter rock near the bottom. This 

 city is also contemplating waterworks, but the source of supply has not 

 been ascertained. 



At Collinsville the public water supply is from two wells 575 and 

 600 feet in depth. The wells are located on the Mississippi River bluff, 

 100 feet above the railway station, and water will rise to a level 120 feet 

 below the surface. The wells have a combined capacity of not more than 

 50,000 gallons per day. The water is slightly saline, but can be drank 

 by most people without discomfort. The supply is probably either from 

 the Coal Measures or Lower Carboniferous sandstone. The drift and 

 loess at these wells is about 90 feet in depth, but probably not less than 

 40 feet is loess. Attention is here called to an error in the altitude of 

 the well mouth given in the writer's paper in the Seventeenth Annual 

 Report (p. 811), the altitude being 565 feet instead of 465 feet as there 



