Stevenson.] Ol— [Feb. 5, 



The section obtained in passing from Rich Mountain to the Ohio em- 

 braces the whole of the Upper Carboniferous as found in West Virginia, 

 and, if begun on the east slope of the mountain,- includes also a very 

 large portion of the Lower Carboniferous. The anticlinal valley of 

 Tygarts' River is cut out of the Lower Carboniferous series, which is 

 well exposed on each wall to the crests of the mountains. On top of Rich 

 Mountain we find the Great Conglomerate forming the crest throughout 

 Randolph county. On the western slope of the ridge are the Lower 

 Coals, which pass under the surface before reaching the Buckhannon River 

 in Upshur county. The Lower Barren Group is well exposed toward the 

 foot of the mountain near Roaring Creek, and thence westward in the 

 bluffs for nearly forty miles; but, owing to the flattening of the dip near 

 Roaring Creek, it is the surface series for only a few miles in the area 

 examined. Northward from the Baltimore and Ohio Railroad, or, better 

 peihaps, at the State line, the Upper Coal Group finds its eastern outcrop 

 several miles from Laurel Hill, but followed southward this outcrop is 

 seen api^roaching the crest of the axis until near the railroad it crosses it. 

 Along our southern line the fold becomes very gentle, so that the Pitts- 

 burg crosses its crest and has its outci'op nearly twenty-five miles east 

 from it. The eastern bomdary of the group is very tortuous. The Upper 

 Coals extend westward almost to the line of the Ellenboro' fault, where 

 the Lower Barren Group is thrust up. This continues to the especially dis- 

 turbed area known as the " Oil-break," in which the Lower Coal Group 

 is exposed. Beyond the " break " to the Ohio River the only rocks ex- 

 posed are those of the Lower Barren. The region lying west from the 

 Ellenboro' fault will be described separately. 



The Upper Barren Group is cut off by the Ellenboro' fault, but east- 

 ward from that for nearly twenty miles its rocks are those covering the 

 surface, those of the Upper Coal Group being found only in the deeper 



The Coal Measures. 



In this paper the terms, Uppar Barren, Upper Coal, Lower Barren, 

 and Lower Coal, as designations of the several groups into which the 

 Coal Measures are naturally divided, are used in precisely the same sense 

 as in my previous paper. 



Upper Barren Group. This group, which includes all the rocks 

 above the Waynesburg Coal, covers a large extent of territory, whose 

 western line is the Ellenboro' fault. The eastern outcrop is an ill-defined 

 line, passing a little west from Troy, in Gilmer county northward, and 

 coinciding almost with the western line of Lewis county. It crosses the 

 Northwestern Railroad near Wolfe's Summit, eight miles from Clarks- 

 burg, and running irregularly northeast, reaches the Baltimore and 

 Ohio Railroad about three miles north from Fairmont, passing finally 

 into Pennsylvania nearly four miles west from the Monoagahela River. 



The northwestern boundary in West Virginia is aline passing from the 



