PHYSIOGRAPHY OF THE REGION. 173 



PRESENT INVESTIGATIONS. 



During the past season the writer has done considerable field work in 

 this territory, and though the area examined was mainly confined to that 

 embraced within the limits of the Dublin atlas sheet, still enough of the 

 adjoining territory was covered to render the main structural features 

 apparent. The work is not intended to be final ; hence the map accom- 

 panying this paper simply embodies the results obtained, and is pro- 

 visional and subject to revision in its details. Its main features, however, 

 are essentially correct, but difi'er so widely from those determined hereto- 

 fore that the writer deems it well to present them now, believing that 

 they have an important bearing on many perplexing questions regarding 

 the structure and stratigraj^hy of this portion of the Appalachian valley 

 and indirectly of the whole eastern portion of the continent. 



PHYSICAL FEATURES. 



Physiographically this area is the southward extension of the Shenan- 

 doah valley or, more truly, the northward extremity of the Great valley 

 of East Tennessee. It is bounded on the northwest by the first of the 

 prominent valley ridges, Little Walker or Brushy mountain, from which 

 it is separated by the first great structural break, Walker Mountain fault. 

 On the southeast there is no topographic boundary to the field, the map 

 simply representing the area studied, but it includes the major portion 

 of the valley. Macks mountain, the southeastern limit of the valley, is 

 but three or four miles distant from New river, but it involves the un- 

 determined Ocoee sediment and is purposely omitted from the map. 



The general surface of the region under consideration is a peneplain 

 that probably dates back to Tertiary times for its origin and represents a 

 period when the general elevation of this portion of the continent stood 

 much lower than at present. Since then the history has been a repeti- 

 tion of oscillations, but the aggregate amount of these movements has 

 resulted in the uplifting of the peneplain to' its present altitude, about 

 2,200 feet above sealevel. The streams, acting under the stimulus of 

 this rapid increase of gradient, have cut deeply into the plain in their 

 efi'ort to keep pace with the rapid increase in elevation. The New- 

 Kanawha river, being the largest stream in the region, has cut most 

 deeply into the level surface, but even this stream has not held its own 

 against the general uplift ; consequently today we find it flowing at an 

 elevation ranging in this area from 1,700 to 2,000 feet, and its channel 

 marked by rapids and small falls, showing that it is still very active in 

 its work of reaching a baselevel. 



