734 THE ILLINOIS GLACIAL LOBE. 



Wells are usually of sufficient strength for household or farm use, but Mr. 

 J. T. Lafferty, of Martinsville, an old resident of the county, states that the 

 strongest wells seldom yield more than 10 barrels a day, and a large number 

 will not afford more than one barrel. Wells are usually obtained at a 

 depth of 15 or 20 feet from pockets or thin beds of gravel or sand asso- 

 ciated with the till. In portions of the county wells have been sunk to 

 depths of 40 feet or more, and such wells usually obtain their supply from 

 gravel below blue till. In the vicinity of Marshall, however, sandstone is 

 entered at about 20 feet, and wells are obtained after penetrating it a few 

 feet. 



INDIVIDUAL WELLS. 



The wells at Marshall which enter sandstone are estimated to yield, in 

 some cases, 100 barrels a day, and many of them are but 25 feet in depth. 



In the vicinity of Martinsville a few wells have been sunk to a depth 

 of 70 or 80 feet, but they are usually obtained at 15 or 20 feet. 



At Casey the deepest wells are about 100 feet, but the great majority 

 are between 18 and 25 feet in depth. 



On the Wabash bottoms, in the southeast part of the county, wells are 

 usually obtained at about the level of the river. On the higher terraces 

 they need to be sunk 50 or 60 feet. They penetrate fine gravel or sand. 



COLES COUNTY. 

 GENERAL STATEMENT. 



Coles County is situated in the east-central rjart of the State, with 

 Charleston as the county seat, and has an area of 520 square miles. The 

 Kaskaskia Rh r er passes southwestward across its northwest corner, and the 

 Embarras River passes southward through the eastern part of the county. 

 The greater part of the county is tributary to the latter stream, but is 

 imperfectly drained, like the neighboring counties on the north and west 

 already discussed. The Shelbyville morainic system crosses the southern 

 part of the county in an east-to-west course, leaving but a few square 

 miles in the extreme southeast and southwest corners outside its limits. 

 This morainic system has a breadth of 5 or 6 miles and a relief of 75 to 

 100 feet above the plain south of it. It stands only 30 to 50 feet above 

 the plain on the north. 



