CHAPTER V. 
By EpwARpD ORTON. 
THE IRON ORES OF OHIO, 
CONSIDERED WITH REFERENCE TO THEIR GEOLOGICAL ORDER AND 
GEOGRAPHICAL DISTRIBUTION. 
The geological series of Ohio begins with rocks of Lower Silurian 
age, and extends well toward the close of carboniferous time. Iron ore 
is mined in but one of the ten or more leading formations into which 
the scale is divided. 
In the Lower Silurian rocks of the State no notable accumulation 
of iron, except the sulphide, is found. 
In the Clinton limestone of Upper Silurian age, there is a moderate 
development of the “fossil ore,” for which this formation is famous. 
The Clinton ore has been found in three counties of Southwestern Ohio, 
viz., Clinton, Highland and Adams. It has been mined in but one, 
viz., Clinton, and there but on the smallest scale. A small furnace was 
built on Todd’s Fork, a few miles northwest of Wilmington, many 
years ago, upon the outcrop of the Clinton limestone, which carries at 
this point a few feet of lean, calcareous ore. The details of the experi- 
ment have not been recovered, but it is certain that a little iron was 
produced by the furnace in its brief history. It made but a single 
blast. 
The ore is quite in keeping with the general character of this 
anomalous and remarkable deposit. It is a red hematite, sometimes 
consisting of flattened grains, and sometimes replacing and intermixed 
with a highly fossiliferous limestone. Red rocks are as a rule barren ' 
of fossils, the presence of the salts of iron in water to any considerable 
amount being fatal to most forms of life, but in the Clinton ore we 
have a rock abounding in the characteristic fossils of Upper Silurian 
time, and yet carrying enough red oxide of iron to make it one of the 
valuable ores of the country. 
