196 GEOLOGY OF OHIO. 
It is but an unusually clear illustration of the law which guides all good 
geologists in their study of the Coal Measures, that identity of relative 
position is not necessarily evidence of identity of strata. 
SUMMARY. 
The available coal area of Carroll county is circumscribed. The strata 
of the Barren Group are the only ones exposed in London, Perry, Lee, 
Fox, and Hast townships, and in by far the greater portion of Har- 
rison, Union, Center, Augusta, and Orange. The three coal beds of 
this group are exceedingly variable, both as to thickness and quality, so 
that little dependence can be placed in them as sources of supply. Coal 
No. 7 becomes of really workable thickness only at Leesville and in Fox 
township, near the Jefferson county border. Indeed, in the latter it is 
s to be of importance only because of necessity. At Leesville, 
where it is about four feet thick, the coal is of inferior quality and 
useful only for domestic fuel. The amount of pyrites, visible to the eye 
and inseparable, is so great as to render the coal worthless in manufac- 
ture of either gas or iron. No. 7a is nowhere of economical value. 
Though occasionally thick enough to be worked, it always yields inferior 
coal. No. 7b is available only at Harlem, and there because the coal is 
so soft that the ease of mining counterbalances the disadvantage of thin- | 
ness. With the sole exception of Norwich, in Muskingum county, Har- 
lem is the only locality north from the Central Ohio Railroad where the 
coal is mined. Every where else the bed is too thin or the coal is too 
slaty to be of any economical value. In Perry township, Coal No. 6 can 
be obtained at a depth of not more than seventy-five or one hundred feet, 
if the boring be made near the saw-mill, about one mile from Perrysyille 
on the road to Palermo, and at the same distance, if made say two miles 
from Perrysville on the road to Kilgore. If struck at either of these 
localities, it would probably be of some value, as to the west and south- 
west of Perrysville it is rarely less than four feet thick, and usually of 
very good quality. In the northern portion of the county, beyond Car- 
rollton, the same coal can be reached at a depth of from fifty to twenty 
feet in any of the deeper valleys, the distance diminishing northward. 
If one may judge from the rapid diminution in thickness and deteriora- 
tion in quality shown by this bed when followed northward, it is doubt- 
ful whether any expenditure in search of it would be judicious. 
When proper means of transportation can be secured, Coal No. 6 will 
assume very considerable importance. In its full development it is con- 
fined to the Conotton valley, in Union, Monroe, and Orange townships, 
