2G8 On tie Parallelism of Coal-Seams. 



80 feet apart. At Fredericksburg again, the distance between coals 

 No. 4 and No. 6 is only about 30 feet ; but in passing from this point 

 eastward to Mineral Point, Tuscarawas county, the interval increases 

 to 104 feet ; coals No. 5 and 5a coming in between them. At Steu- 

 beaville, the interval between coals No. 6 and No. 8 varies from 502 

 to 564 feet ; while, going westward, this interval diminishes to less than 

 400 feet along the western outcrop of the Pittsburg seam. On the 

 banks of the Ohio, between Wheeling and Bellaire, the two coal-seams 

 next above the Pittsburg bed are seen, in a single exposure, to vary 

 from 12 to 35 feet in the distance which separates them. On the 

 banks of the Ohio, west of Wheeling, coals No. 8 and No. 9 are about 

 150 feet apart ; three coal-seams, 8a, 8b, and 8c, being interposed 

 between them. Thirty-five miles west of this locality, the distanee 

 between coal 8 and coal 9 .is only 50 feet, with no intermediate seams 

 (Stevenson), iit Morgautown, West Virginia, on the east side of the 

 Monongahela, the interval between the Pittsbui-g coal and the next 

 succeeding one above (Redstone) is over 50 feet, consisting of lime- 

 stone, 14 feet ; shale, 3 to 10 feet ; sandstone, 35 feet. On the west 

 side of the river, three miles below, the distance between the Pittsburg 

 and Redstone coals is less than 20 feet; the limestone remaining con- 

 stant, the sandstone having entirely disappeared (Stevenson). 



Any required number of cases like the preceding might be cited, but 

 these, as it seems to me, will suffice to show; that the intervals between 

 our coal-seams are not constant. I learn from Professors Dawson, 

 White, Cox, and Worthen, our most experienced coal geologists, that 

 similar examples to those I have cited are not uncommon in the coal- 

 fields which they have so carefully studied.* 



The fixllacy of the theory of Professor Andrews, as I think, consists 

 in the su])position that the subsidence of our coal areas has been ahvays 

 continental or general; whereas, as it seems to me, the evidence is 

 varied and abundant that this subsidence w'as often very local, and 

 that in the long interval which elapsed between the formation of one 

 coal-seam and the accumulation of carbonaceous • matter above it, tb.e 

 strata were sometimes warped and folded in the most local and cora- 

 j)licated way. It is also apparent that the deposition of the materials 

 forming the strata of the coal-measures was often quite irregular. 

 This is conspicuously shown by the limited reach of the great sandstone 

 wedges which sometimes locally separate or replace the_ more constant 

 elements, the limestones, shales, and coal-seams. In some instances 

 these beds of sandstone occupy narrow troughs of erosion ; sometimes 



■■'■ See also the report of Professor Kainsay, in the Report of the CoalCoiuuilssioiiers (England), 

 vol. i., pp. 121 and 145. 



