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 a so 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 towriship, 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- 

 roUton fragments of a compact clay were observed about midwaj' 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. 



