HOCKING VALLEY COAL FIELD. 945 
here also consists of the normal seam, a little thicker and purer than 
the northern phase, immediately overlain by the Hocking Valley sup- 
plementary seam. The first, second and third benches of the great 
seam, the latter of which contains more or less inferior coal, as a 
rule, which is known as bone coal and soft coal, constitute the original 
seam. The supplementary seam was built upon it with but a very 
slight interruption. The original seam includes about 5 feet of the 
compound bed, leaving the same amount of coal, but of much less 
value, to be referred to the additional deposit. 
This district produces more coal to the acre than any other in the 
State, the yield under favorable conditions being 9,000 tons of lump coal. 
The result is certainly no more than should be expected, when it is re- 
membered that a seam 9 feet thick, carries 15,768 tons to the acre, 
the specific gravity of the coal being 1.29. Of this amount, 9,000 tons 
constitutes 57 per cent. 
The Shawnee and Straitsville coal endures handling and transpor- 
tation somewhat better than the coal of the Monday Creek and Hocking 
Valley districts, being inferior, in fact, to but one field of the State in 
this respect, viz., the block coal field of the Mahoning Valley. On 
these accounts it is especially adapted to the lake trade and for ship- 
ment to the north-west. 
The mines of this district are without exception level-free or hill 
mines. Most of them are under good cover, and over much of the 
territory the hills rise high. The dip is quite regular, though there 
are, of course, local interruptions. It is fair to count on 25 feet to the 
mile, in a direction between east and south-east. 
The roof, wherever normal, is very strong and safe, consisting 
of 10 to 20 feet of yellow or gray shales. Occasionally the shales: 
have been cut away by descending sandstone. In this case, while’ 
the roof possesses greater strength then ever, it is still counted less’ 
desirable than shale, the coal being generally more or less troubled 
by the approach of the sandstone. The floor of the coal is a heavy 
bed of fire-clay, which, however, makes a fairly good bottom. It 
occasionally “creeps,” in wet workings, or where entries and worked 
rooms are allowed to fill with water, but, with good management, no 
difficulty is experienced in this respect. 
60 G. 
