198 | GEOLOGY OF OHIO. 
truth is that in those localities there is no evidence of the presence of 
iron ore which would justify the expenditure of a single dollar in ex- 
ploration. A foot or two of good ore, if readily accessible and compact, 
would be valuable; but if, instead of being in a compact layer, it is dif- 
fused throughout ten or twenty feet of shale, or is separated into layers 
one inch thick and one foot apart, we have not ten or twenty feet of iron 
ore, but simply a worthless mass. This is aso self-evident truth that one 
is surprised to find sensible persons so deceived as to doubt it. 
Nodular ore is found over No. 7a, near Harlem, but not in quantity to 
be worth any thing. In Perry township, near Mastersville, at the same 
horizon, plate ore of excellent quality occurs, but further examination, 
which should be made, is necessary to determine its full value. 
The blackband over Coal No. 7, in Rose and Brown townships, is un- 
doubtedly valuable, and is deserving of careful investigation. Those 
searching for it should remember that this ore is by no means persistent, 
frequently changing into nodular ore in shale, and this in turn giving 
place to shale containing a considerable percentage of iron, but too small 
to render it available. Still, wherever Coal No. 7 is observed it would 
be well to make an excavation upon it, ten to fifteen feet from the out- 
crop, so as to reach sound ore if it be present. In Brown township Coal 
No.7 is about one hundred feet above Coal No. 6, which is the upper coal 
at Pekin, Oneida, and is worked by Mr. R. B. Hamilton near Waynes- 
burg. In this township much money has been wasted in exploring the 
shale underlying the Crinoidal limestone. 
Fire-clay.—No critical examination was made of any of the plastic 
clays, as in every case they gave evidence of the presence of sufficient 
iron to render them valueless. On the road from Cannonsburg to Car- 
rollton fragments of a compact clay were observed about midway between 
Coals Nos. 6 and 7, but the position of the bed could not be ascertained, 
though careful search was made. It is probably very thin. The com- 
pact clay under coal No.5 was observed only in Rose township. Though 
by no means persistent, frequently giving place to the plastic variety, 
this clay is of so great economical importance and of such limited distri- 
bution, being found elsewhere only at Mt. Savage, Maryland, and near 
Grafton, in West Virginia, that diligent search should be made at every 
exposure of Coal No. 5. This clay will probably prove of more advan- 
tage to this valley than would an equal thickness of blackband ore. 
Clay for the manufacture of brick can be obtained from the subsoil. 
Building stone of good quality is not plenty. The sandstones, for the most 
part, are shaly. 
