924 GEOLOGY OF OHIO. 
The result is plain to be seen. The Baird Ore of Perry county is the. 
Red Ore of Union Furnace and the Limestone Ore of Hope Furnace and 
southward. The Gray Limestone which is thin and uncertain in Perry 
county increases in volume in Hocking county, and is found steady and 
well developed in Vinton county. It gains this steadiness, indeed, in © 
Washington township, Hocking county, ten miles west of Nelsonville. 
The Nelsonville Coal instead of underlying the Gray Limestone, ranges 
from thirty five to forty-five feet above it in Perry, Hocking,and Vinton | 
counties. This interval is observed until Bloomfield township, Jackson 
county is reached, where an increase of ten feet in the interval is made, 
the coal at Keystone Furnace being fifty-five feet above the limestone 
and being here known by its southern name, viz., the Sheridan seam. 
In the next six miles; a further gain of ten feet oecurs, and from that 
point to the Oh‘o Niver, a very reliable average of sixty-five feet is 
maintained. The country between Zaleski and Keystone Furnace has 
been repeatedly traversed in this interest, and hundreds of sections have 
been measured. No obscurity or doubt remains as to the general order. — 
The usual interval between the Gray Limestone and the Sheridan Coal 
in the southern counties has been shown to be sixty-five feet. Prof. 
Andrews traced the seam northwards until the interval was reduced to 
fifty five feet. In the Report of Progress for 1870, page 179, he gives a 
section near Keystone furnace in which he notes the fact that a coal 
which “is doubtlessthe the Sheridan seam,” “‘is nearer thelimestone than 
usual.” 
In Volume I, Geology, page 233, he quotes the section referred to above 
and adds the following sentence, viz., “If the coal given in the above 
section is the Sheridan coal, there was probibly a mistake in the meas- 
urement of tne space between it and the limestone.” There is no 
mistake, however, in the identification or the measurement. The coal is 
the Sheridan coal and the measure is fifty-five feet. 
On the other hand, the Mineral City seam (Nelsonville) has been fol- 
lowed southward from Zaleski until at Keystone Furnace itis found to be 
fifty five feet above the limestone. There is no room for doubt or question 
as to this fact, that the upper coal at Zaleski is the ccal fifty five feet 
above the Gray Limestone at Keystone. The wholesceries has been followed 
without a break from the first point to the last. The fire clay parting © 
by which No. VI is characterized through all this region, makes its iden- 
tification easy and c-rtain. A few of the intervals between the limestone 
and the coal in this district will be given here. 
In Section twenty two and twenty-five, Elk township, the intervals 
are respectively foity two and forty fect. The coal is here know as the 
Carbondale seam. In Section twenty-five, Madison township (Vinton 
