THE IRON ORES. 413 
Union Furnace obtained its chief supply from this seam in Starr town- 
ship, and Logan Furnace drew quite largely for its ore from this horizon 
in Falls township. The block ore of Green bonnship makes a small 
contribution to Craft’s Furnace. 
The ore ranges, as usual, from 4 to 8 inches in thickness, averaging 
about 5 or 6 inches. All that has been mined is outcrop ore, taken 
from stripping benches. ‘This grade yields somewhat more than 40 per 
cent. of iron, the quality of which is excellent. The ore is low in 
phosphorus, and its sulphur can be easily controlled. It has a tendency 
in some places to run into flint. The future production must be limited 
by the extent of available outcrop, as the thinness of the seam forbids 
the following it under cover. ‘There is still a large amount of territory 
that can be reached by existing lines of communication. 
There are several other block ores in the field, but none of them 
has been worked to any notable extent. 
The Baird ore of this district is the ‘ Limestone ore” of the 
Hanging Rock field. It has already been described as occurring to a 
small extent in Reading and Clayton townships, of northern Perry 
county. It becomes an element of real value in Pike, Jackson and 
Monday Creek townships, of southern Perry, and also in Gore, Green 
and Starr townships, of Hocking county. There are also valuable 
bodies of it in the highest hills of Falls and Washington townships, 
but the area here is quite small. 
Throughout the territory now described, it has been worked on a 
large scale for many years. Not only the furnaces already named, but 
three others in addition, viz., thé Bessie, the Thomas Iron Company’s 
and Winona furnaces, have all obtained large amounts of ore from this 
thoroughly known and thoroughly approved seam. It retains all the 
characteristics that have given to it its excellent reputation in Southern 
Ohio. It occurs in the same form, and in the same stratigraphical 
associations as there, but its thickness is a little less than in Lawrence 
and Jackson counties. It averages 8 inches here for the whole territory 
against 10 inches in the southern parts of the field. Of course, it often 
rises to 12 inches, and sometimes to double this measure, but this extra 
volume has generally to be paid for by corresponding decrease in the 
surrounding territory. It is separated from the Lower Kittanning coal 
by a very white seam of clay (the Kittanning clay), which ranges be- 
