906 GEOLOGY OF OHIO. 
Galliats coe cites sori scree en teipieve fein tscta mhciey tues ee -------Gallia county 
Le) 9 RES SEP Sra ORs A NS, APA AI iN SHORE UNM Jackson county 
Winton (225 osu sara ei sie ae nie ace heap ere ene Vinton county. 
VOR 6556 6563 6565 6h06 G5046 Hodb bond Hono sbScoo cbodosisoss Quand s hna SiS GOT, 
It is also known to be worked at all of the eastern furnaces of J ackson 
eounty. There is no characteristic by which the most experienced iron 
master of the district can distinguish a specimen from the Hecla Fur- 
nace from one taken from Nelsonville or Gore. 
The gray ore consists of odlitic grains of carbonate of iron, which are 
each invested with a whitish covering of fire-clay and ‘finely divided 
silica. It contains in this state about thirty to thirty-five per cent. of 
iron. The outcrop ore rises frequently to forty-five and fifty per cent., 
and yields in the furnace over forty per cent. 
There is scarcely a trace of sulphur in the ore, and phosphorus, exists 
in very small proportions. 
Its average thickness in Southern Ohio may be taken as ten inches, 
but north of Vinton county, the average does not exceed eight inches. 
Locally, however, it rises to several feet in thickness. From less than 
one-half acre near McArthur, on the “Speed farm ” of Dr. Wolfe nine 
thousand tons of ore were taken. 
The steadiness an constancy of the seam go far toward making amends 
for the scanty volume. It is found where it is due and can be followed 
under cover with confidence and success. Several of the older furnaces 
of Lawrence county obtain a large proportion of their ore by drifting. It 
is subject to cut-outs of course, but there are as few in this seam as in 
any other geological horizon of the district—a district by the way that 
is remarkable for the steadiness of its series. 
More than sixty Ohio furnaces make this ore their chief supply, and 
the jiron yielded by it is the standard of quality throughout the Ohio 
Valley. 
11. At an int 
to fifty feet in t 
erval varying from thirty feet in the northern counties 
he southern counties, another very steady seam of ore 
ie 
A 
ecurs. In the Kentucky furnace district it is known as the “ Black 
Kidney” and is there highly esteemed. It has no generally received 
name to the northward, but it will be recognized by all familiar with the 
geology of this district from its relation to Coal No. VI, with which it is 
closely associated, underlying it at an interval of twoto ten feet. It is 
a very compact and close-grained, blue carbonate, lying in large blocks 
and kidneys, in the clays that support the coal. It is also characterized 
from the Hocking Valley to the Ohio River by holding beautifully pre- 
served coal plants. Leaflets of ferns, bits of bark, and branches are 
