CLAEK COUNTY. 19 



The beds intervening between this limestone and coal No. 7 do not 

 make their appearance in this county, bnt by visiting the shafts now in 

 operation on the west side of the Wabash river, one and a half miles 

 west of Terre Haute, I fouud a portion of them outcropping at the 

 surface, and the remainder had been penetrated in the shafts and were 

 reported to me by the gentleman in charge of the work. The section 

 from the limestone to the coal would be as follows : 



Ft. 



Brownish-gray, compact, fine-grained limestone 4 



Green, bine and purple shales 10 to 15 



Sandstone, locally in tolerably heavy beds 13 



Argillaceous shales, with bauds of iron stone 40 to 50 



Bituminous shale 1 to 2 



Coa'.Xo. 7 5 



This is undoubtedly the "Danville coal" which has been extensively 

 worked at Danville and at several other points in Vermilion county, 

 where it ranges from 4 to 7 feet in thickness, and is equivalent to No. 7 

 of the Illinois section. There it is overlaid by a soft black shale tilled 

 with fossil shells in which the calcareous matter is replaced with pyrite, 

 giving to the fossils a beautiful metallic lustre, but unfortunately in 

 many cases the pyrite decomposes if not protected from the atmosphere, 

 and the fossils are soon destroyed. Locally No. 7 is overlaid by a heavy 

 bed of limestone, as at the Equality and Bowlesville mines, in Gallatin 

 county. At the mines opened west of Terre Haute, we found no well 

 preserved marine fossils in the soft shales over this coal, although a 

 careful search was made for them. Fragments of fossil wood, either 

 silicious or replaced by pyrite, were abundant in the debris taken from 

 the shafts here, as well as at Bowlesville. 



In any attempts that may be made in Clark county to mine coal by 

 shafting to the lower coals, this would be the first seam reached, and its 

 approximate depth at any given locality may be determined by the 

 remarks already made, and especially by reference to the county section. 

 In the northern portion of the county the distance from the Livingston 

 or Quarry creek limestones to this coal would be considerably less than 

 in the southern part, for reasons already stated, namely, the thinning 

 out the intervening beds to the northward, and consequently this 

 variation in the relative thickness of the beds in different parts of the 

 county should be duly considered in estimating the probable cost of any 

 extensive operations for coal mining. 



Economical Geology. 



Coal. — From what has been already stated in the preceding pages, it 

 will be. inferred that there is no great amount of coal accessible in this 

 county except by deep mining. In the thin seams outcropping at Mr. 



