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 the 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 tabies of analyses of this coal, exhibit its characteristics 
in this part of the field: 
McGinnis’ BANK, OLD STRAITSVILLE. 
| 1 2. 3 4 
Specific gravity.) 1.291 1.239 1.307 1.247 1.248 | 1.244 1.241 
Watery sas] 7.90 7.20 7.60 6.00 535 | 7.55 | 8.15 
Volatile matter .|; 34.63 32.29 29.65 S115) 30.48 | 35.61 27.46 
Fixed carbon.. - 54.29 59.44 52.77 59.41 57.21 54.90 61.73 
Aighig oe seem 3.18 1.07 9.98 2.44 6.96 1.94 2.66 
Total ....-.| 100.00 100.00 100.00 100.00 100.00 | 100.00 100.00 
Sulphuneseerere 0.98 0.73 0.68 0.50 122 1.05 0.78 
Color of ash ....|Dull white} Reddish. | White. [Yel’sh gr’y| Grayish. | White. | Reddish 
Nature of coke:.| Compact.| Pulv’t. | Pulv’t. | Pulv’t. | Pulv’t. |.....-.-|-......- 
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. 
