Stevenson.J •-'^ [August. 20, 



Exposures become poor near the top of Black mountain along all of the 

 streams which were followed, and the vipper part of the section Avas not 

 made out. Sandstones and shales seem to be continuous for 200 feet above 

 the highest coal bed seen in place ; but there is certainly one eoal bed within 

 the undetermined interval beyond, as fragments of cannel were found 

 abundantly at fully 200 feet up ia that space. No limestone occurs in 

 beds, but some nodular limestone was discovered within six feet above No. 

 17; and fragments of an exceedingly impure limestone, with a cone-in-cone 

 structure in its more argillaceous portions, were found above No. 6. 



Calahan creek is the main tributary of Roaring fork ; its larger branches 

 are known as Kelly's, Church House and Preacher runs. Looney creek 

 is an important stream entering Roaring fork near its junction with 

 Pigeon fork. On all of these, as well as on Pigeon fork, exposures were 

 found, but the upper part of the section was obtained satisfactorily only 

 on Preacher run. 



Tlie study was not sufficiently prohmged to admit of classifying the beds 

 or of determining their relations to the groups recognized in Pennsylvania. 

 There seems, however, to be a natural line of division about midway in 

 the section : for, above the coal bed, No. 19, to within 250 feet of the top of 

 the column, no thick coal bed occurs. It may be that the lower portion, 

 for about 833 feet, is equivalent to the Lower Coal Measures of Pennsyl- 

 vania as represented on the Great Kanawha river of West Virginia, and 

 that the upper portion is equivalent to the Lower Barren Group of Penn- 

 sylvania. I have noticed in another place* the extraordinary thickening 

 of the Lower Coal Measures southward ; how this group, rarely more than 

 350 feet thick in Pennsylvania increases southward from the line of the 

 Baltimore and Ohio railroad in West Virginia, until in Randolph county it 

 is 700 or 800 feet thick. The increase continues southward and on the 

 Great Kanawha the same group is upwards of 1200 feet thick. 



On the Kanawha, the top of this group is distinct ; for the "flint ledge," 

 occurring in close proximity to the Mahoning sandstone, is a well-marked 

 horizon. But on the headwaters of Powell river the "flint ledge" seems 

 to be wanting, and no traces of it could be found. The division here, 

 therefore, is arbitrary and a final determination of the matter must be post- 

 poned until opportunity has been had for less hurried investigation. It is 

 quite possible that the full thickness of the group is not given in the sec- 

 tion, as the lower intervals were merely estimated. 



If the top of the Kanawha series be at coal bed, No. 19, some representa- 

 tive of the Upper Productive Coal Series of Pennsylvania may be sought 

 .near the crest of Black moantain ; for while the Lower Productive Coal 

 Series shows the remarkable increase southward, the Lower Barren Group 

 shows no such increase. Its extremes are 500 and 700 feet, both of which 

 may be found within the limits of a single township in different parts of 

 Pennsylvania. No system of variation in this group has been discovered, 



* Proceedings of this Society for 1875. Notes on Geology of West Virginia, 

 No. 11. 



