§48 GEOLOGY OF OHIO. 
The most careful estimates I can make indicate that we have in all 
these townships, in this single deposit, the equivalent of a continuous 
sheet of coal averaging ten feet in thickness and covering an area of 
100,000 acres. Hstimating a cubic yard of such a body ot coal to weigh 
one ton, and that it could all be mined, this one district is capable of 
producing over 1,600,000,000 tons of coal, or over 100,000,000 tons in 
excess of all the coal mined in the United Kingdom of Great Britain 
from 1854 to 1870, both inclusive. 
The average annual production of coal in the United States for the 
last three years past is a little under 48,000,000 tons. This coal-field 
would suffice to produce that amount continuously each year for thirty- 
three years. It is not, however, so much the increased thickness as the 
remarkable change in the character of this coal that has attracted to it 
s0 much attention. Coal No. 6 is the most persistent seam in the State, 
and furnishes a large portion of the coal mined in it. It is ordinarily a 
melting or coking coal, with high heating power, an excellent steam 
and mill coal, but contains too much sulphur to make a valuable coke 
for the smelting furnace. It leaves a peculia® purple ash, so that in 
nearly all the counties of the State where this coal is used the refuse 
heaps from the stoves and furnaces discloses the fact to the trained 
observer, who is rarely misled by this indication. But in the Great 
Vein Region this coal becomes very hard and dry burning. It melts or 
swells in the fire, but slightly, is remarkably free from sulphur, and 
burns with little smoke, leaving a white ash. It is not an open burn- 
ing, but a remarkably dry burning coal. It has not, generally, the finely 
laminated structure and thin bands of charcoal of the Block Coal, which 
eauses the latter to split up so readily when fired, but, when best de- 
veloped, is almost as compact and homogenous as anthracite, and, after 
the volatile matter is driven off, leaves a mass of glowing coais much 
resembling an anthracite fire. It partakes somewhat of the character of 
eannel, and in places, especially in the upper bench, resembles a splint 
coal. It has been classed as both of these, and has been sold in New 
York as “Ohio Cannel.” “The appearance of the coal, and its chemical 
analysis indicate, and practical tests have demonstrated, its great excel- 
lence for smelting iron, and good results are obtained from its use in the 
smelting furnace without any mixture of coke. As adomestic fuel, it is 
not excelled by any coal in the State. Careful comparative tests, made by 
weighing large quantities of the coal and burning it in grates and stoves, 
and comparing the character and quantity of the residuum, show that, on 
the average, it leaves a rather larger percentage of ash than Coal No. 1, 
but a less quantity of cinder, burning almost entirely to a fine white ash- 
