SOUTHERN APPALACHIAN REGION. 



127 



of about 100 feet. For a distance of about 10 miles be- 

 low the falls the river flows in a series of cascades through 

 a narrow gorge, whose sides ai'e from 600 to nearly 2,000 

 feet high, the walls being cut down through the eroded Lin- 

 ville quartzites into the granite below. (See PI. LXXII.) 

 In the first 6 miles below the falls the descent averages 208 

 feet to the mile, and the total descent from the head of the 

 falls to the lower end of the gorge, a distance of about 10 

 miles, is 1,800 feet, as determined by a line of levels. 

 Along the vipper 6 or 7 miles of this distance the bottom of 

 the gorge is scarcety wider than the stream. The total fall 

 of the stream from its source in Linville Gap to its mouth 

 is about 3,030 feet in a distance of about 36i miles, the 

 average fall per mile being about 83 feet. 



The Watauga River also rises near Linville Gap, and 

 flows first in a northeasterly and then in a northwesterly 

 direction, its length from its source to Butler, Tenn., 

 where it leaves the mountainous region, being about 33 

 miles. The total fall in this distance is about 2,000 feet, 

 and the average slope, therefore, about 61 feet per mile. 

 Of this 2,000 feet, between 900 and 1,000 feet are found 

 in the first 6 miles, where the sti'eam rushes down the 

 slopes of Grandfather Mountain. 



As is the case with most of the other streams rising on 

 the western slope and flowing westward across the elevated 

 plateau, this stream has its channel for a part of its course 

 in a rather broad and smooth valley before entering the 

 steep and rocky gorge of its middle course. Here it cuts 

 its wa}^ through the Unaka mountains in a deep canyon, 

 about 8 miles in length, where the fall averages about 

 65 feet per mile, but is very much greater at numerous 

 places, the channel being extremely rough and ]>roken. 

 The depth of the gorge through the Unakas is nearly 

 2,000 feet, but the walls slope down much more gently 

 than those of the Linville just described, though they 

 often show precipitous rock cliffs several hundred feet in 

 height. 



The Unaka range on the western edge of this plateau, til'^unakas'*"'^* 

 unlike the Blue Ridge, has slopes equally steep on 

 . both sides, descending often some 4,000 feet from the 

 crest of the mountains to the stream beds. In the upper 

 part of their courses all of the rivers of the Unakas par- 

 take of the nature of mountain torrents, with the greatest 

 fall near their sources, and in their lower courses they flow 

 in valleys where there has been much clearing, the amount 



