PALiEONTOLOGUCAL REPORT OF GEOLOGICAL SURVEY. 553 



No. 12 is either united with it or not formed as in western Kentucky, 

 we find in Pennsylvania, according to Lesley's description of the upper 

 Coal Measures, a bed of coal, one foot thick above the great limestone, 

 covered by two thick formations of sandstone, one fifteen feet, the 

 other thirty-five feet, separated by shales, and a thin bed of limestone — - 

 the whole thickness of these strata being sixty-five to seventy feet. 

 In Kentucky, between 12 coal, and the first coal above, there is nine- 

 ty-five feet of sandstone and blue slate; and from this coal, which, for 

 convenience sake, we wiil call No. 13, there is thirty-six feet of shales 

 and limestone, to a five feet black slate, which contains some coal, and 

 then thirty-seven feet of brown slate and limestone, to a bed of coal, 

 (say No. 14,) which is thirteen inches thick. In Pennsylvania, we 

 find, in the same space, fifty feet of sandstone and shales, to a coal 

 eighteen inches thick, and then fifty-five feet of limestone and shales, 

 to another coal one foot thick, covered by four feet of brown shales, 

 and twenty feet of sandstone. And more, if we count the whole thick- 

 ness of the strata from the highst vein of coal in Pennsylvania to the 

 Pittsburg vein, we find it to be marked by Lesley at four hundred 

 feet, and the distance from our 14 coal to No. 8, or Well coal, is 

 nearly exactly the same, viz: three hundred and ninety-five feet. 



Truly this extraordinary concordance of the Coal Measures, at ma- 

 ny hundred miles distance, is a very remarkable geological fact; and 

 mny be accepted as a proof, not only of coevity, but of continuity of 

 the now separated coal-fields. 



It may be said that a coevity of formation would, perhaps, call in 

 existence the same formations, on both separate basins, as well as on a 

 continuous one. This is possible, but there is nothing to prove it. 

 On the contrary, we find, on the true borders of the great Apalachian 

 coal-fields, viz: on its eastern and northern limits, many peculiar ac- 

 cidents of formation, great irregularity of thickness in the strata, dis- 

 tortions, cavities, subdivision of the bed of coal, which show the action 

 of the sea on its shores, where the sand is unequally distributed, and 

 where some small basins are closed and separated from the main one ; 

 and also on the western borders of the Apalachian, as well as on the east- 

 ern limits of the western Kentucky coal-fields, the veins of coal, and 

 even the intermediate strata, have a remarkable uniformity of thick- 

 ness. From Massillon, Ohio, to the Ohio river, at Nelsonsville and 



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