Stevenson. J ^^^ [August 20, 



Streams cross the several faults and mountain ranges exhibits the faintest 

 trace of any cross-fracture in the rocks. 



At first glance, one might be inclined to suppose that the faults have in- 

 fluenced the direction of drainage. A deep valley has been excavated 

 along the front of Stone mountain ; another, digged out of the contorted 

 limestone and shale of the Lower Silurian, follows the fault of Poor Valley 

 ridge ; the West Forli of Stone creek, a branch of Clinch river, has made 

 for itself a broad valley near the Stone Mountain fault east from that of the 

 South Fork of Powell river. These valleys arrest one's attention at once 

 and they lie very near the lines of fault. 



But valleys of equal importance are found where no fault exists to direct 

 their course or extent. Tlie monoclinal valley between Wallen's ridge and 

 Powell mountain above the North Fork gap is as broad as the Turkey 

 cove between Wallen's ridge and Poor Valley ridge ; Wallen's valley, be- 

 tween Wallen's ridge and Powell mountain beyond the North Fork gap, 

 is a monoclinal, and is one of the finest valleys in Southwest Virginia ; the 

 broad valley, followed by the North Fork of Clinch after it leaves the 

 North Fork gap, is far removed from any line of faulting, and lies not far 

 from the axis of the synclinal. 



Erosion along the line of the Stone Mountain fault is interrupted, and 

 the valley is far from being continuous ; a well-marked divide separates 

 the South Fork from Powell river and a bold divide separates the South 

 Fork of Powell from the West Fork of Stone creek. The condition is simi- 

 lar to that in the valley between Wallen's ridge and Powell mountain ; for 

 a low t.ivide intervenes between Wildcat creek and the North Fork of 

 Clinch, while a high divide separates the latter stream from Wallen^s 

 creek, which flows along Wallen's valley. 



The conditions in the immediate vicinity of the faulted lines appear to 

 difter in no essential feature from those observed in less disturbed locali- 

 ties. It is evident : 



First. That the course of the streams has not been determined by the 

 lines of fiiult. 



Secondly. That erosion along the f\iulted lines is essentially the same in 

 character and extent with that in localities v/here no faults exist. 



At the same time one may not ignore the fact that the faults have done 

 much to hasten erosion along their lines as well as along the lines of 

 streams belonging to the drainage system of Powell river, although one 

 iwAj be inclined to exaggerate the extent of this influence by forgetting 

 that that drainage system is the important one in the region examined, 

 while only a fragment of the Clmcli river system falls within the area. 



There must have been drainage before the faults existed. Evidently the 

 rocks were more or less flexed previously ; for the dips in Wallen's ridge 

 and Powell mountain are almost due east, whereas those on the northerly 

 side of the faults are north-west to north-northwest. It seexus not wholly 

 improbable that the faults are of later date than the disturbance which pro 



