HOCKING VALLEY COAL FIELD 937 
The first of these causes is much the more to be dreaded, as the ex- 
perience of.the field thus far has shown that when the coal fails from this 
cause, its failure is likely to be final, whereas, a narrow trough in the 
seam may be filled with sandstone, which, if crossed directly, may show 
the coal of proper thickness immediately beyond. As the coal approaches 
a clay vein, its character is changed. It becomes hard and curly, and 
thus more difficult to mine. The roof also becomes irregular: and 
dangerous, and the advance of a few yards will often carry the miner 
from good ground into an entirely worthless mixture of coal, clay and 
shale. 
Clay veins are the principal sources of trouble in all of the mines 
here named, but they are often more or less closely associated with the 
descent of sandstone, and it is the latter element that has worked the 
greatest harm in the region to the southwest of Corning. A great 
“(want”’ in the coal has been known for a number of years in Sections 
20, 21, 28, 29, 32 and 33, Monroe township. It has been connected by 
some with a similar want in the eastern sections of Salt Creek, but 
according to present knowledge they are distinct, a body of coal of full 
thickness occupying the interval. It now appears that this first-named 
failure of the coal extends directly through to Corning, and that the 
trouble of Mines Nos. 13 and 15 indicates the northern boundary of this 
“want,”’ so that parts of Sections 22 and 15 must be added to the sec- 
tions already named, making the total area of the ‘ want” more than 
2,500, and probably more than 3,000 acres. | 
Another serious interruption of the Great Vein, which has also 
been known for a number of years, is found in Sections 24, 25, and 36, 
of Salt Lick, and in the adjacent Sections 31 of Monroe, 36 of Trimble, 
and 6 of Ward township. No doubt other territory will also be found 
damaged by this want, but not enough is known to warrant the laying 
down of boundaries for either of these two or more broken ones. The 
hypothesis of an ancient water-course, coming from the north-west and 
eroding this territory shortly after the coal was formed, does not match 
well with present knowledge. It would require more than one river to 
explain the facts, and the erosion of the sea would seem to be a more 
probable agent of the waste than the drainage of the land. 
The facts as to these wants are indicated on the map of the Hock- 
ing Valley field which accompanies this chapter, but the qualification 
already made needs to be repeated, viz., that good coal may hereafter 
