716 THE ILLINOIS GLACIAL LOBE. 



use a well for supply, but the depth is not ascertained. A coal shaft 1 mile 

 east of Coatsburg, reported in the Geology of Illinois, passed through a clay 

 similar to that at the mill in its lower portion, which was separated from the 

 overlying- till by a black soil, the following being the section, supplemented 

 by notes taken by the writer from the residents and from exposures near 

 the coal shaft; it should be compared with the section given on page 62. 



Section in a boring for coal a mile east of Coatsburg, Illinois. 



Feet. 



Soil and yellow clay 6 



Gray or ashy clay, resembling a soil & 



Yellow till, becoming gray or blue near bottom 10-15 



Bin --ray till '--- 70-75 



Black soil - .2* 



Stratified clay 6 



Tough blue clay 20 



Total drift 118 



At the County Infirmary near Coatsburg, a well entered rock at a 

 depth of 165 feet. The upper 65 feet appears to be largely till, below 

 which is a blue silt with sand partings, perhaps a water deposit. A boring 

 at Mr. Henry's, near the infirmary, penetrated a similar section and entered 

 rock at 160 feet. Another well on the infirmary farm is only 58 feet in 

 depth. After penetrating about 40 feet of till it entered sand and gravel, 

 which furnished the water. 



At Camp Point wells are usually obtained at 25 to 30 feet. A few 

 have, however, been sunk to a depth of 45 or 50 feet, at which depth the 

 first rock is struck. 



At Clayton rock is usually entered at a depth of 30 or 40 feet. The 

 depth of wells supplying the waterworks has not been ascertained; the sys- 

 tem was but recently introduced. 



At Liberty several deep wells have been sunk which show a range in 

 thickness of drift from 47 feet to at least 90' feet. A well at Collins's mill, 

 90 feet in depth, has the following section: 



Section of a well at Collins's mill in Liberty, Illinois. 



Feet. 



Till, mainly of yellow color 50 



Blue clay containing much wood, but with few pebbles 35 



Sand with water : 5 



Total depth ; 90 



A well in Liberty, at William Lytle's, after penetrating 52 feet of till, 

 entered a sandy blue clay containing wood. Water was found in this clay. 



