Appalachian area in Pennsylvania and the Virginias. 39 



Mountain, on the northerly side of the Saltville fault, shows in 

 Bland County the Umbral consisting of red shales and sand- 

 stones, and the Vespertine made up of sandstones, shales and 

 coal beds, with an impure siliceous limestone at the top. The 

 Umbral has not much less thickness than in Bedford County of 

 Pennsylvania, but the Vespertine is decidedly thinner. The 

 same structure appears along the Walker Mountain exposure, 

 and even in that north from Draper Mountain in Pulaski County 

 where the siliceous limestone at the top of the Vespertine is 

 distinctly shown in the railroad cutting at only 4 miles east 

 from Max Meadows station. This is interesting, as the locality 

 is but 12 miles from the Archasan, whereas in Pennsylvania 

 this limestone is barely recognized in Huntingdon County at 40 

 miles from the Archaaan of South Mountain. 



The Umbral contains occasional streaks of coal in Pulaski 

 and Bland Counties, but these are wholly unimportant. The 

 especial economic interest of the Vespertine lies in its coal beds, 

 which attain considerable importance near New River along 

 the Walker and Price Mountain faults in Montgomery, Pulaski 

 and Wythe Counties, as well as along the Saltville fault in 

 Bland and Smyth Counties. These have been described by 

 Rogers, Lesley, Fontaine and the writer, so that only an inci- 

 dental reference to them is necessary here. Not less than seven 

 or eight beds exist, but only three appear to become valuable. 

 All are practically worthless except in the vicinity of New 

 River, where a semi-bituminous coal is obtained, which is es- 

 teemed for domestic use, despite the ash, which varies from 11 

 to 39 per cent, as appears from the analyses published by Mr. 

 A. S. McCreath.* 



The fault of Walker Mountain quickly lessens beyond the 

 westerly line of Wythe County and thence to Tennessee no 

 Lower Carboniferous rocks are shown between the Saltville 

 fault and the Archaean. A great change in those rocks begins 

 in Smyth County. The shales of the Umbral lose little of 

 their thickness, but limestone appears toward the bottom and 

 increases in thickness so rapidly that within 15 miles it has be- 

 come the prominent feature of the group. Meanwhile the 

 sandstone and shales of the Vespertine lose their importance ; 

 the coal beds are reduced to mere streaks and the calcareous 

 sandstone at the top becomes a calcareous shale or disappears. 

 This changing condition continues until, at Mendota in Wash- 

 ington County, about 15 miles from the Tennessee line, the 

 Vespertine sandstones and shales have practically disappeared, 

 while the Umbral limestones have increased vastly in thick- 

 ness, though not at the expense of the shales. The section at 

 Mendota is : 



*The Mineral Wealth of Virginia, &c, 1884, pp. 130-131. 



