100 J. J. STEVENSON — CARBONIFEROUS OF APPALACHIAN BASIN 



Hodge's section in Wolfe seems to make the matter clear, for from that 

 county southward the sandstone is divided and new shales and new 

 coals come into the section, which were unknown farther north. Mr 

 Lesley's notes show also that even at a considerable distance eastward in 

 the basin coarse materials prevail in the lower part of the section.* 



The geology of eastern Pulaski is described by Professor Crandall in 

 connection with that of Whitely, which is east from Pulaski and south 

 from Laurel. The Sharon appears to be at very nearly the top of the 

 section in eastern Pulaski. In eastern Pulaski the section reaches to 

 but a little distance above the Sharon sandstone, which with the under- 

 lying beds is well shown in that county, as well as in western Whitely 

 and along a branch of the Cumberland river in Laurel. Within this 

 area the section assumes such importance that Professor Crandall terms 

 it the Rockcastle group. 



The upper plate of the Rockcastle group, the " Corbin lentil " of Mr 

 Campbell, is from 100 to 200 feet thick, and the rocks between the coal 

 beds are mostly coarse sandstones containing layers of quartz pebble 

 conglomerate; but evidently the rock is less coarse in the bottom 150 

 feet. The lowest coal bed rests on the Lower Carboniferous limestone 

 or is separated from it at most by only a few feet of shale. The other 

 coal beds are approximately at 50-60, 90, 130, 240, and 310 feet above 

 the limestone. The second, third, and sixth beds, known as the Bry van, 

 Main, and Barren Fork coals, are of great economic importance and mark 

 horizons which show coal in nearly all of the sections for fully 100 

 miles northward. The other beds become locally valuable. The third 

 bed is mined in Pulaski, Wayne, Whitely, and Laurel counties. It is 

 the " Main " coal of the Cumberland and Rockcastle River region, and it 

 was the important bed almost 50 years ago, when Mr Lesley made his 

 study. The bed is usually double, with splint coal in one or the other 

 bench and varies in thickness from 4 feet 4 inches to 4 feet 6 inches. 

 The upper workable bed is usually in three benches with a total thick- 

 ness of about 4 feet.f 



The variations of the Rockcastle or lower portion of the Pottsville 

 have been followed along the border from the Ohio river to the Ten- 

 nessee line. On the Ohio river, where the most westerly exposure is 

 considerably east from the line of Pike county, Ohio, the thickness is 

 only a few feet ; away from the river the Sharon sandstone reappears 

 above the Sciotoville clay and thickens towards the south and south- 

 west, while underneath these appears the shaty portion, which is prac- 



*Jos. Lesley : Fourth Report, pp. 475-477. 



A. R. Crandall : Menifee County, p. 11. 

 t A. R. Crandall : Geology of Whitely and part of Pulaski, pp. 15, 16, 18, 20, 21. 



