126 Coal Mines of Virginia. 
the granite, and [ can discover no very good reason for disa- 
greeing with them in this particular; but, on the contrary, 
many circumstances concur to strengthen the opinion that itis 
really co-extensive with the granite. The coal is now pro- 
cured from at least 25 different pits, opened at convenient dis- 
tances through an extent of from 50 to 70 miles. It every 
where commences at the upper surface or termination of the 
body of granite. Some suppose that it is imposed on the gran- 
ite; and others, that a thin stratum of slate is interposed be- 
tween the coal and granite. It is always found covered by the 
slate. The granite is inclined to the horizon, at an angle of 45 
degrees, and the coal has the same inclination. And since the 
coal, as far as it has been discovered, is found to accompany 
and correspond with the granite, why may we not suppose that 
it continues to accompany the granite, where it has not yet 
been discovered ? 
At Heth’s pits the coal is 50 feet thick, measured on 4 line 
perpendicular to the surfaces of the extreme strata. At some 
of the pits between Heth’s and James’ river, it is 30 feet thick; 
and at the river, not more than 25 feet. The thickness of the 
coal on the north side of James’ river, at the pits in Henrico and 
Hanover counties, is variable, but at no place greater than 2 
feet; and to the south of Heth’s, in the pits extending to the 
Appomatox river, it is still less thick. These facts would i- 
duce the supposition, that the coal was deposited in a bed, neat 
the centre of which Heth’s pits were sunk. But on the other 
hand, the coal is distinctly stratified, and the number of strala 
increases as the coal proceeds from the surface of the earth; of 
course, therefore, the farther you proceed from the outer extrem 
ity of the coal, the thicker the body of it will be found ; and frm 
the inclination of the coal, the farther you are from its outer & 
tremity, the deeper it must be under the surface of the earth. 
Heth’s pits are 100 feet deeper than any that have yet been 
sunk ; and all the pits that I have seen appear to be nearer #0 
the outer extremity of the coal. We may conclude, therefore, 
that if the others had been sunk as far from the outer extremit) 
they would have been as deep, and the coal would have beet 
found as thick in them as in Heth’s, Heth’s pits, now 80°" ® 
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