554. GEOLOGY OF OHIO. 
to one hundred and seventeen feet. These facts show conclusively that 
the successive subsidences were not continental, but occurred along the 
lines of neutral axes, giving a wedge-shaped form to many of the strata. 
Indeed, had those subsidences been continental, the lower coal would 
_ every where be buried beneath al! the other members of the Coal Measure 
‘rocks, except where the latter had been carried away by erosion, and the 
last coal deposited would extend farthest up the slopes of the hills which 
bordered the coal territory, and would be the first encountered upon ap- 
proaching the coal field. | | 
The outcrops of this coal are found in every township and upon the ~ 
slopes of almost every hill, and generally with evidences indicating a 
remarkable thickness, but few of them have been satisfactorily tested. 
Iron Ore—Just above this horizon are deposits of iron ore extending 
over most of the county, from which large quantities could be mined 
should there be a sufficient demand for it. In places the slopes of the 
hills between this coal and the next above, are covered with the ore; and 
on John Simmons’s land, in Knox township, where these fragments are 
very abundant, it is reported that a solid deposit of ore eight feet thick 
was penetrated in sinking a well. 
Coal No. 8a.—A sandy shale separates the blue limestone from the coal 
designated as No. 4 in the preliminary report on this county, but which, 
from its unimportant character throughout the State, is now designated 
as No. 3a. The interval ranges ordinarily from eighteen to thirty feet; 
but in Salt Creek township measurements have been made where it is 
fully seventy feet. 
Nowhere in the county have I found this ccal of sufficient thickness to 
be profitably mined, although its outcrops are numerous and its horizon 
can be accurately determined in nearly all parts of the county. On the 
Killbuck Coal and Mining Company’s property, in Mechanic township, 
it is associated with ironore in the overlying shales, and it is possible 
that further explorations’ may show that the two minerals can be profit- 
ably mined together. The limestone which overlies it in parts of Coshoc- 
ton county, appears occasionally in the eastern part of Holmes, and care 
is required not to confound it with the blue limestone below. 
Coal No. 4.—The shales and sandstones between the last and Coal No. 4, 
or the grey limestone seam, range from twenty-five to fifty-five feet in 
thickness. The material is generally a thin-bedded shaly sandstone of 
no value, but in places it would furnish fair flagging stone. This coal 
attains its maximum thickness, in the county, in Salt Creek township, 
where it is three and a half feet thick, with six feet of limestone resting 
directly upon it. Very good coal can be obtained. from the openings here, 
