IRON MANUFACTURE. 439 
All the iron ores of any value in Ohio are found among the rocks 
of the Coal Measures, and although they are quite abundant in this 
formation, it is only in a few regions that they are in sufficient quanti- 
ties to sustain important iron industries, so that the chief supply of ores 
is now, and will be, obtained from other States. The rich and pure 
specular ores of Lake Superior, the magnetites of Canada, etce., 
readily transportable by the waters of the great lakes to her northern 
shores, meet first in the coals of Ohio the supply of fuel, in which those 
regions are so deficient. Hence it is that the coals of Ohio are the 
most important element in her mineral industry, and the one upon which 
the existence and progress of Ohio as an iron manufacturing State must, 
of necessity, be mainly dependent. ‘The character and extent of the 
Coal Measures has already been most thoroughly discussed in portions 
of the geological reports, and the continuation and value of each seam 
of coal and deposit of iron ore traced in all their variations of import- 
ance through the entire area. The geological map already published by 
the Survey, and the local maps of the present volume, exhibit the ex- 
tent of this area in Ohio. The various points of the manufacture being 
denoted, their relations to each other, to the different parts of the coal 
area, and to the various means of transportation, will be readily ap- 
preciated. 
The iron manufacture of the State is divided into several districts, 
and a description of the peculiar conditions is given in another place of 
each region separately, with quite full details, referring to their situa- 
tion and relations, the fuel area as used, the furnaces and their economy, 
the general facts of the methods of working, and the character and uses 
of the iron produced. It is intended, however, to make a summary of 
the general conditions of iron manufacture in the State, under the follow- 
ing heads, namely: Means of transportation; general character of the 
Coal Measures in Ohio ; the fuels used, their characters, etc. ; the different 
ores employed; general facts and results of the blast furnace practice ;. 
and finally, statistical facts regarding the manufacture in the State. 
The districts and places where the manufacture of iron is principally 
carried on, are situated in the eastern part of the State, as all the min- 
eral fuel employed is derived from the coal measures which underlie 
the eastern third of the State. Facilities of transportation, the existence 
of other industries or large communities, however, are creating import- 
ant iron manufacturing establishments at considerable distances from 
