Coal underlies the greater part of the area of the county, but it is not found in large quantities, or mined to any great extent, excepting in a belt comprising about 25 per cent of the county's area. It is found at a depth below the surface, of from two to more than one hundred feet, but at an average depth of from fifty to seventy. The veins are from twelve to thirty-six inches in thickness. The quality is good, the mines numerous, and the shipments are great. It is used extensively by the railroad companies, and for local, domestic and manufacturing purposes.
Limestone is found in all parts of the county.
It is of an excellent quality for building purposes. A great number of the buildings of the county are constructed of this material. Besides this the stone is used to a great extent for fencing. Yellow ochre is found in abundance in every township. There is also an almost unlimited supply of fire and pottery clay, which is utilized to some extent.