of the Ap'palachian Mountain System. 57 



the Hiwassee. The bottom of these basins preserves in the middle, an 

 altitude of from 2000 to 2700 feet. The height of these transverse chains 

 is greater than that of the Blue Ridge, for they are from 5000 to 6000 

 feet and upwards ; and the gaps which cross them are as high, and often 

 higher than those of the Blue Ridge. In these interior basins are also 

 found groups, more or less isolated, like that of the Black mountains, 

 which, with the Smoky mountains, present the most elevated points of 

 the system. 



Here then through an extent of more than 150 miles, the mean height 

 of the valley from which the mountains rise is more than 2000 feet ; the 

 mountains which reach 6000 feet are counted by scores, and the loftiest 

 peaks rise to 6700 feet; while at the north, in the group of the White 

 mountains, the base is scarcely 1000 feet, the gaps 2000 feet, and Mount 

 Washington, the only one which rises above 6000 feet, is still 400 feet 

 below the height of the Black Dome of the Black Mountains. Here 

 then in all respects is the [culminating region of the vast Appalachian 

 system. 



It is worthy of notice that in the Appalachian, as in many other sys- 

 tems of mountains, the culminating points are situated, neither near the 

 middle, nor in the neighborhood of what may be called its central axis, 

 which is here the Great valley, but near the northern and southern 

 extremities, and on the eastern side, almost outside of the system. 

 These culminating regions seem almost exceptions to the normal struc- 

 ture of the system. The high mountainous region of North Carolina 

 which has just been described is, from the bifurcation of the Blue Ridge 

 near the great bend of the New River, an additional fold which attaches 

 itself on the east along the principal chain which bounds the Great 

 Valley, just as the swell, which runs along the east of the Connecticut 

 River, upon which the group of the White mountains is situated, is an 

 additional fold attaching itself to the east of the normal chain of the 

 Green mountains. 



The second region of this southern division is the continuation of the 

 Great Central Valley which is divided by a general swell of the land 

 about the sources of the Holston, into two distinct basins, the one in 

 Virginia, narrower and more elevated, which in the basin of the New 

 River, rises gradually towards the south from an elevation of 1600 feet 

 to 2600 feet ; the other in Tennessee, where the valley widens to nearly 

 sixty miles between the Smoky mountains and the Cumberland mountains, 

 but where it has a mean elevation of not more than about 1000 feet, 

 that is, only one-half of the height of the neighboring valleys in the 

 mountainous region of North Carolina. 



The third region is that of the plateaus which, in Tennessee, are 

 reduced to a table land about thirty or forty miles wide, called the 

 Cumberland mountains on account of the abrupt edges which it pre- 

 sents upon the east and the west, and which give to it the appearance 

 of a mountain chain. Further north, in Virginia, the plateaus expand 

 and fill a vast area to the west of the Clinch and the Cumberland 

 mountains and extend over a part of Kentucky, the central portion of 

 which, near Lexington, preserves an altitude of more than 1000 feet. 



