OHAFTE^R IV. 



THE COAL. FIELDS OF OHIO. 



By Prof. Edward Orton. 



Areas. — The rocks of the Carboniferous system, in which all our 

 coal seams are embraced, constitute the surface rocks of about ten thou- 

 sand square miles in the southeastern quarter of the state. The counties 

 in which these rocks are found in whole or in part, are the following: 



Trumbull, Mahoning, Columbiana, Carroll, Jefferson, Harrison, Bel- 

 mont, Guernsey, Noble, Monroe, Washington, Morgan, Athens, Meigs, 

 Gallia, Lawrence, Scioto, Jackson, Vinton, Hocking, Perry, Muskingum, 

 Coshocton, Holmes, Tuscarawas, Stark, Wayne, Medina, Summit and 

 Portage. A few insignificant outliers are found in other counties. But 

 what has been said is by no means the same as saying that there are 10,000 

 squares miles in Ohio, under any one of which square miles, one or 

 more coal seams exists. There are large areas within the general bound- 

 ary named above in which, although the rocks are included in the Car- 

 boniferous age, coal seams were never formed. There are other consid- 

 erable areas from which the coal seams that once existed have been 

 entirely removed by the processes of denudation that have been at 

 work during the millions of years, in which this part of the continent 

 has stood above the level of the sea. There are still other considerable 

 areas in which coal seams are found in their regular places in the series, 

 but too thin, or too impure, or too much broken by the accidents of 

 their early history, to possess any economic value. Finally, there are 

 considerable sections in which, while half a dozen coal seams are repre- 

 sented, but one or two are found in volume large enough to justify 

 mining, at least, under present conditions. 



The general statement, therefore, that the Ohio coal field embraces 

 ten thousand square miles of territory, is calculated to give an erroneous 

 and misleading impression. In any case, the assumption that the value 

 of a coal territory can be properly estimated by measuring the surface 

 which it occupies, is altogether inadmissible. One district may have 

 but a single seam that is worth mining, while another may have two, 

 three or four seams. Neither can the value of a coal field be determined 

 by the aggregate thickness of its several seams. In one district, there 

 may be a single seam, five feet in thickness, for example; and in another 



