264 GEOLOGY OF ILLINOIS. 



FEET. 



5. Coal* (and shale) No. 6? 16 



6. Fire clay ? 



7. Very hard gray rock 69 



8. Soft clay shale 175 " 200 



9. " " ? 75 " 100 



The thinness of the upper coal is evidently due to a partial wearing away of 

 the seam by the current of the river, before the deposition of the Alluvium. 



The first digging only passed through the fire clay, and a brine yielding one 

 bushel of salt to one hundred and seventy gallons of water was boiled at such a 

 rate as to yield from forty to fifty bushels per week, with eighty kettles. Be- 

 low the lower coal, a cavity of eighteen inches was found, from which flowed a 

 much stronger brine, one hundred gallons of which gave a bushel of salt. 

 The production was now about one hundred and twenty bushels per week, and 

 the price, $1.50 per bushel. In 1825, Major Vance bought the works, and 

 deepened the well, the boring being continued at intervals until 1827, but the 

 strength of the brine did not notably increase. After the construction of 

 canals and railroads, they were unable to compete with the Syracuse salt, and 

 work was stopped and never resumed. The brine probably came from the 

 sandstones at the base of the Coal Measures, and would have been found of 

 greater strength if the well had been deepened considerably. From these 

 lower beds, wells bored on the east side of the "Wabash, have obtained brine of 

 a strength of from 7 to 8 Beaume. It would seem that, with the abund- 

 ance of coal on the spot, the reduction of this ought to be made to pay. . 



This abundance of brine in the lower strata makes it doubtful whether pure 

 water can be obtained in this county by artesian wells sunk in the rock. In 

 nearly all parts of the county, however, water can be obtained from the quick- 

 sand below the boulder clay, which, in most cases, will rise high enough to be 

 readily pumped to the surface, and in some cases, in the north part of the 

 county, flows out naturally, as in the numerous flowing wells of Iroquois 

 county, which are probably supplied from the same source. 



*The enormous thickness of this coal, as reported by the well borers, has always been a 

 mystery to the coal miners, since no such bed appears upon the outcrop, and the boring re- 

 ferred to in Major Kirkland's letter did not reach any corresponding bed. It was long sus- 

 pected that at least a part of this was shale, and the parties who bored an " oil well " at Rock 

 Ford, on Salt Fork, report finding, at a considerable depth (amount not given) below coal No. 

 7, " twelve feet of black shale and four feet of canncl." If this report is correct, this is prob- 

 ably coal No. 6, the changed condition being only the result of the more complete action of 

 the causes which gave to that seam, two miles above Danville, a top bench of nine inches of 

 caunel. Until, however, some shaft has been sunk io this lower seam at some considerable 

 distance west of the outcrop, I shall not be willing to believe in any such condition of things 

 at that level. 



