COAL MEASURES. 7 



Coal No. 7 is well developed on the northern, eastern and southern 

 borders of the Illinois coal field, ranging in thickness from four to 

 seven feet. On the western borders of the field it is usually only 

 from one to three feet thick, and is generally neglected for the 

 thicker seams below. It is the main seam at Danville, the upper 

 seam of workable coal in the shafts in La Salle county, and the 

 main seam in Gallatin, Saline and Williamson counties, where it 

 sometimes attains a maximum thickness of eight or nine feet. In 

 the last named county an excellent coke is made from it, which 

 finds a ready market in St. Louis for the use of the iron foundries 

 at that point. 



This is a brief resume of the coal seams in the lower Coal Meas- 

 ures, as they appear around the borders of the coal field, and it is 

 from this part of our coal area that our present supply of coal is 

 mainly obtained. The shaft at Decatur has demonstrated that at least 

 one of our main coals has retained its average thickness to the center 

 of the field, and future experiments with the drill must determine 

 whether any of the coals below No. 5 can be made available, when 

 the supply from that has been exhausted. All experiments with the 

 drill in the central and southeastern portions of the State, whether 

 undertaken in search of coal or for any other purpose, should be 

 carefully conducted, with the end in view of determining, as far as 

 possible, the extent of our coal resources in that portion of the 

 State, where the main coals, if present at all, are from six hundred 

 to a thousand feet or more below the surface. 



The increase in the coal products of the State from 1867 to 1880 

 was about 400 per cent., the product of 1867 being about 1,500,000 

 tons, while according to the U. S. census report for 18SO the pro- 

 duct of that year is placed at 6,089,514 tons, equal to an annual 

 increase of about 30 per cent. The census report, moreover, includes 

 only such mines as are worked in the regular way, while there is a 

 large amount mined annually for local use by the process of "strip- 

 ping" on the outcrops of the thinner seams, of which that report 

 would have no record. This would no doubt swell the amount for 

 1880 to at least 6,250,000 tons. This increase of our coal products 

 has been mainly on the northern and western borders of the field, 

 where the coal deposits are the most accessible, and the facilities 

 for market are better than in other portions of our coal area. 



At Olney a boring was made about two years since in search of 

 artesian water, and the following record of the work was furnished 



