Stevenson.] v)0 [March 18, 



and Montgomery, and Prof. Fontaine* lias given interesting details 

 respecting the Vespertine coals. Mr. C. R. Boyd, of Wytheville, Va., 

 has published a work, dealing with the economics of South-west Virginia, 

 in which are given many geological details, with a map which topo- 

 graphically is a very notable improvement on its predecessors. The 

 writer is under obligations to these publications which will be acknowl- 

 edged in the proper connection. 



The general type of structure is practically the same as that found in 

 the areas already described, and it has been well represented by Lesley, 

 who in his memoir on Tazewell county, f gives an ideal figure, which 

 with his permission is reproduced as Fig. 1. The upthrow side, except in 

 the case of cross-faults, is the south-east, and the Lower Carboniferous is 

 found for greater or less distances in contact with the Lower Silurian 

 limestones along most of the fractures. These faults are not simple, as is 

 well shown in the Clinch group, but subordinate and cross-faultsdo not 

 appear to arise directly from those of the principal system ; and where- 

 ever a fault, either principal or subordinate, was followed out, it was found 

 to originate or to terminate in an anticlinal. The faults are not parallel, 

 they bear no relation whatever to the folds except such as is purely for- 

 tuitous, and their direction is wholly independent of the strike. A regu- 

 lar fault such as the Saltville exhibits this well, the upthrow group being 

 in contact with different groups at different localities, owing to the influ- 

 ence of anticlinals on the downthrow side. Some interesting facts of this 

 kind were given in the previous memoirs ; others will be given in this, 

 going to show independence of the faults and the folds and, as the writer 

 intimated several years ago, suggesting very strongly a difference in age. 



The structure is hardly so simple as that of the counties already 

 described and the description cannot be given in so direct a manner as 

 that of the other counties. 



The Lick Mountain Anticlinal. 



Lick mountain, at a little way southward from the railroad in Wythe 

 county, is due to a strong double anticlinal, which diminishes rapidly east- 

 ward and is soon recognizable only as a gentle fold, followed by the Val- 

 ley pike north-eastward for six or seven miles in Pulaski county. It was 

 not traced beyond New river. How far westward it can be traced in 

 Smyth county was not ascertained. It brings up the Potsdam in Wythe 

 county, so as to form a very rugged mountain about fifteen miles long, but 

 eastward it sinks so as to be crossed by the Knox shales before Reed creek 

 has been reached ; thence, as far as it was followed, no beds below the 

 Knox shales are shown on the axis.ij: Some anticlinals in the Knox lime- 

 stone were seen between the Lick mountain fold and the southern edges 

 of Wythe and Pulaski counties, but they were not followed. One is 

 crossed by the New river, very near the Wythe lead mine. 



*Amer. Journ. of Science, Jan. and Feb., 1877. 



tProc. Amer. Phil. Soc, Vol. xii, p. 490. 



X The easterly limit assigned to these shales on the map is conjectural. 



