W. M. Fontaine— Vespertine Strata of Virginia. 41 



Passing south, into still more weakened strata, the sudden de- 

 velopment of the great fault near the Sweet Springs, in Monroe 

 county, to the east of the southerly prolongation of the Alle- 

 ghany, in like manner relieves the country to the west from 

 the upheaving force, causing the Alleghany, and the contorted 

 belt on its west, to disappear, and the mountain chains to as- 

 sume a more easterly course. From this point southward, in 

 the region of greatest tension, the fractures are more profound 

 and numerous. Any residual impulse, unrelieved by the faults, 

 seems to have been exhausted in producing flexures in the im- 

 mediate vicinity to the west of the fault, and in raising the 

 eastern border of the great coal field as a whole, producing a 

 gentle westerly dip toward the Ohio. 



No doubt the great freedom of this area, thus tilted, from 

 flexures of any magnitude, is due in part to the great develop- 

 ment of massive sandstones in the lower Vespertine, and in the 

 conglomerate series in this section, which would produce great 

 rigidity. 



A somewhat detailed explanation of the connection supposed 

 to exist between the faulted and folded portions of the country, 

 and the deep trough occupied by the lower strata of Carbon- 

 iferous age, has been given in the above named " Resources of 

 West Virginia," in the chapter by Mr. Maury on the " Coal 

 Field of West Virginia." 



The Vespertine strata occurring to the east of the limit men- 

 tioned at the beginning of this article, are found in detached 

 belts and patches, mostly of small extent. As might be 

 expected, from the above account of the structure of the coun- 

 try, in the northern and middle portions, they occupy usually 

 the lower parts of synclinal folds, while in the southern portion, 

 they are confined to the vicinity of faults. In each case they 

 are more commonly found along the flank, or at the foot of a 

 mountain, formed by the more resistant lower portion of the 

 Vespertine, or underlying strata. 



The following are the more important of these belts, and the 

 only ones which I propose to notice, since tbey may be taken 

 as true representatives of all the areas to be found in the region 



1. The belt mentioned above, as occurring on the east flank 

 of the Alleghany Mountain, near the White Sulphur Springs. 

 This belt contains the coal strata and plant impressions seen at 

 Lewis Tunnel. It is especially instructive, since it shows the 

 strata lyingimmediately above the Chemung, as well as the junc- 

 tion of these last with the lower portion of the Vespertine. All 

 the strata here are well exposed in the deep cuttings for the 

 Chesapeake & Ohio B. R. 



This belt extends an unknown distance north of the railroad, 



