WELLS OF GLAEK COUXTY, ILLINOIS. 733 



vicinity are usually obtained at depths of 20 to 40 feet. A boring' at 

 Sanford, near the State line, east of Paris, whose section is given on page 

 201, entered rock at 147 feet. 



At Dudley wells are obtained at about 25 feet and are largely through 

 a sandy drift. Between Dudley and Kansas and also to the north of the 

 latter village wells are reported to have passed through a soil below till at 

 35 to 40 feet. 



At Kansas wells are usually 20 to 25 feet and occasionally 40 feet in 

 depth. They are obtained in gravel below blue till. Good wells are esti- 

 mated to yield about 30 barrels of water a day. 



Near Isabel wells occasionally reach a depth of 50 or 60 feet without 

 entering rock. The majority of wells, however, are much shallower. A 

 short distance east of Isabel rock is encountered at a depth of only 25 feet, 

 and wells in the central and eastern parts of the county not infrequently 

 enter rock at 25 feet or less. 



On the plain outside the Wisconsin drift wells are usually obtained at 

 about 30 feet and seldom enter the rock. They are largely through a hard 

 till. 



CLARK COUNTY. 

 GENERAL STATEMENT. 



Clark County is situated on the eastern border of the State, immediately 

 south of Edgar, a portion of its east border being formed by the Wabash 

 River. It has an area of 510 square miles, with Marshall as its county seat. 

 The eastern portion cf the county drains directly to the Wabash, but the 

 western half is drained southward through Hickory Creek, a tributary of 

 the Embarras. The outer moraine of the Wisconsin drift covers a few 

 square miles in the northwest corner of the county. Aside from this the 

 drift of the county belongs to the earlier stages of glaciation. Although 

 the surface was originally very level, drainage lines are sufficiently well 

 developed to remove the surplus rainfall more rapidly than on the flat areas 

 occupied by the Wisconsin drift. The drift has a capping of the compact 

 phase of the loess, called white clay, whose depth is but 5 or 6 feet. As 

 previously indicated, this clay is separated from the underlying till by a 

 black soil. 



The drift of this county is largely a hard till which is brownish yellow 

 at top, but changes to a greyish blue color at a depth of 15 or 20 feet. 



