774 THE ILLINOIS GLACIAL LOBE. 



drainage is mainly southward through the Big Muddy River. A small area 

 in the northeast part is tributary to Skillett Fork, which flows southeast to 

 the Little Wabash. The uplands are coated with white clay, which furnishes 

 a slow absorbent for the rainfall. The portions of the county remote from 

 the main drainage lines have imperfect drainage, the excess of rainfall being 

 disposed of largely by evaporation. 



The glacial deposits are generally thin and but partially couceal the 

 preglacial ridges and valleys. They consist chiefly of a brownish yellow 

 till. Throughout much of the county wells are reported to penetrate rock 

 a few feet for the best supply, but weak wells are often supplied from the 

 drift. No attempt was made to collect well records in the county. 



The Manual of American Waterworks reports that at Mount Vernon 

 the public water supply is from impounded water. The drift in the vicinity 

 of that city is only 10 or 15 feet in depth. 



WAYNE COUNTY. 

 GENERAL STATEMENT. 



Wayne County is situated in the southeast part of the State, with 

 Fairfield as the county seat, and has an area of 720 square miles. The 

 Little Wabash River leads southward near the eastern border of the county 

 and Skillett Fork leads southeastward through the southwestern portion. 

 The uplands are covered with a silt deposit, but as they are more hilly than 

 the counties to the north and west the water is drained to the lowlands 

 readily, and a more compact deposit is found on the lowlands than on the 

 hills or uplands. 



The drift is generally a thin coating averaging scarcely 15 feet in 

 depth on the higher parts of the county. In the lowlands and along val- 

 leys "there is probably a greater depth. The thickness, however, has not 

 been tested by well borings, the wells being obtained at comparatively 

 slight depth from sandy beds in the drift. The drift consists usually of a 

 brown till, which sets in below the white clay or surface silt at a depth of 

 6 or 8 feet. 



INDIVIDUAL WELLS. 



In the northwest part of the county, in the vicinity of Rinard, Blue 

 Point, and Jolmsonville, a large percentage of the wells enter rock at about 

 10 feet and obtain water at 30 to 40 feet or less. 



