JIIEGCILACHAUL WAAWILILIE NGS KONE, SIENE Nilhsysuirsyss eed Me 757 
Present Stream Valley Floor 
Montezuma, Artesian well - 465 - ft. Aoo ft 
Clinton, Coal boring - - 450+ “* Be 
Terre Haute, Oil wells . (MS aes C0 345-360 ft. 
Vincennes, Artesian well - 4oo + ‘ 345 ft. + 
Shawneetown, Ill., Oil boring - 350+ “ 240 “ 
The altitude of the valley floor of the Wabash is apparently 
somewhat higher than that of the Illinois and Mississippi valleys 
in the same latitude, the difference in altitude is, however, not 
very marked. 
In the district north from the bend of the Wabash at Coving- 
ton several borings have been made which show a rock floor 
lower than those on the Wabash. One boring near Oxford, 
Indiana, enters rock at the extremely low elevation of 300 feet 
A. T. A few miles northwest from Oxford, in Iroquois county, 
Illinois, a boring is said to have reached a depth of 4o0 feet 
without entering hard rock. As its mouth is but 660 feet the 
rock floor here may fall below 260 feet A. T.* Unfortunately 
this record is not so trustworthy as the importance of the determi- 
nations of so low an altitude of rock floor would demand. The 
exact depth is somewhat uncertain and there is a possibility that 
the soft Cincinnati shales may have been entered near the base 
and not distinguished from the blue till of the overlying drift. 
The records of the Oxford borings are apparently trustworthy. 
The region north from Covington, Indiana, may present such a 
northward depression, as is exhibited by the portion of the IIli- 
nois near Princeton. 
A few borings in the east central part of Illinois, nearly mid- 
way between the Wabash and Illinois, show a remarkably low 
rock surface. These may be in the line of a valley discharging 
southward to the Kaskaskia, or in tributaries of the Wabash or 
of the Illinois. A well at Monticello, in Piatt county, Illinois, 
reached a level but 352 A. T. without entering rock. One at 
Kenney, in western De Witt county, failed to find rock at 358 
feet A. T. A boring made at Paxton, in Ford county, entered 
rock at 350 feet A. T., while one at Odell, in Livingston county, 
entered rock at 355 feet A. T. It appears from these data that 
* Geol. of Illinois, Vol. IV. p. 237. 
