650 



GEOLOGY OF OHIO. 



ordinarily carbonaceous shale; while the lower benches are the most 

 valuable for ordinary uses, as the coal from them has the highest heating 

 power; the combined product of ihe three benches is preferred for the 

 smelting furnace. 



The seam is well up in the hills, so that good drainage is obtained; and 

 the shale above the coal ordinarily impervious to the water, so that in 

 the best openings the mines are quite dry, and in none of them is there 

 any serious trouble from this cause. In so thick a seam it was antici- 

 pated that the cost of timber for supporting the roof would be excessive; 

 for supports ten feet or more in length, must of necessity be large and 

 straight, or of no value. But it is found, when the roof is undisturbed, 

 that rooms forty feet in width can be worked with no danger, without 

 supports, and there is probably no place in this county where the cost of 

 mining coal is so small as here. Indeed, in the depression of the coal 

 business, proprietors of mines have contracted to deliver coal upon the 

 cars at the rate of sixty-two cents per ton, rather than suspend operations. 

 This would leave little margin for profits, but it will be difficult to find 

 any other locality where coal of any quality can be sold for that sum. 



The following tables of analyses of this coal, exhibit its characteristicB 

 in this part of the field : 



McGiNNis' Bank, Old Straitsvillb. 



No. 1. From bottom layer. 



No. 2. From middle layer. 



No. 3. From bottom of top layer. 



No. 4. From middle of top layer. 



No. 5. From upper part of top layer. 



No. 6. Second sample of middle layer. 



No. 7. Second sample of bottom layer. 



