188 GEOLOGY OF ILLINOIS. 



At Bloomington the shafts were first sunk only to the upper coal, which was 

 worked for a short time, and then the shaft having been deepened, the upper 

 bed was abandoned, and only the lower seam was worked. The difference in 

 quality was very marked at this place, the lower coal being very much superior 

 to that of the upper seam. 



Beneath this coal No. 4, we find, by the boring opposite Peoria, by Voris & 

 Co., two seams of coal at the depths of one hundred and twenty and two 

 hundred and thirty feet, and respectively four and three feet in thickness, 

 which are most probably the equivalents of Nos. 1 and 3, of the general sec- 

 tion referred to. Although we have no positive data, as to the existence of 

 these, or other beds under the coal No. 4, in other portions of the district, yet, 

 from their existence at this point, and from our general knowledge of the 

 development of the lower Coal Measures in this portion of the State, it seems 

 quite probable that these seams of coal might be found at the proper depth in 

 other parts of this, and the adjoining counties. A boring of from two 

 hundred, to two hundred and fifty feet, below the known horizon of No. 4, or 

 from five, to seven or eight hundred feet from the surface in different parts of 

 the district, would probably penetrate all the Coal Measures, and settle all the 

 questions in regard to the existence, and develpment of the underlying coal 

 seams. 



The upper coal seams are perhaps represented in this district, by the bed 

 reached in the Lincoln shaft, and it may be also by the small vein near Wesley 

 City, in Tazewell county, which T. have, in the preceding pages, referred with 

 doubt to a higher level than No. 6, though still admitting its possible identity 

 with that bed itself. In neither of these localities is the seam of sufficient 

 thickness to be worked with much profit, excepting where it might, perhaps, 

 be profitably worked in a small way by stripping along the line of its outcrop. 



Building Materials. This district, as a whole, is within itself but scantily 

 supplied with building stone, the greater portion of its surface being occupied 

 by the Drift deposits, and containing no exposures whatever of the older rocks. 

 Along the Illinois river, however, in Tazewell county, the sandstones of the 

 Coal Measures have been quarried to some extent to supply the local demand, 

 and in some localities appear to afford a stone suitable for foundations, cellar 

 walls, etc. The limestone beds which also occur in the Coal Measure strata in 

 this region, though generally of inconsiderable thickness, may also furnish a 

 limited supply for the same purposes, as well as for the manufacture of lime. 

 The limestone ledges noticed as occurring on Salt creek and Lake Fork, in Lo- 

 gan county, also furnish a fair material for the rougher kinds of masonry, and 

 have been considerably quarried for this purpose. Dimension stone, etc., when 

 used in this dirtrict, are brought from beyond its limits, in great measure from 

 the quarries at Joliet. 



