PHILOSOPHICAL SOCIETY OF "WASHINGTON. 61 



gradually gains in both width and altitude, consisting of many- 

 parallel ranges, with fertile valleys between, of which the great 

 valley of Virginia is the largest and best known. In Pennsylvania 

 the summits vary from 800 to 2,500 feet. Toward the south the 

 chains become more numerous and in Virginia the Peaks of Otter 

 reach 4,000 feet. The extreme eastern range is called the Blue 

 Ridge, the extreme western the Cumberland Mountains, or, more 

 properly, Plateaus, while the high range or ranges between are, in 

 general, called the Alleghanies. 



From the New River south the system becomes much more 

 complex; The main chain, hitherto called the Blue Ridge, is 

 deflected to the west, and for 250 to 300 miles, in a circuitous chain, 

 under the names of Iron, Stone, Bald, Great Smoky, and Unaka 

 Mountains, forms the boundary line between North Carolina and 

 Tennessee, rising frequently to heights exceeding 6,000 feet ; while 

 the more easterly range, retaining the name of Blue Ridge, and 

 finding its southern terminus at Caesar's Head, in South Carolina, 

 where it turns abruptly to the northwest, reaches even loftier alti- 

 tudes, Mitchell's high peak being accredited with 6,717 feet. 



In North Carolina these two ranges are more than 50 miles apart, 

 are partially connected by transverse ranges, and, for more than 

 100 miles, constitute a great central plateau, like that of Colorado 

 on a small scale. 



As says Prof. Guyot, "Here then through an extent of more 

 than 150 miles the mean height of the valley from which the 

 mountains rise is more than 2,000 feet. The mountains which reach 

 6,000 feet are counted by scores, and the loftiest peaks exceed 6,700 

 feet, while at the north, in the group of the White Mountains, the 

 base is scarcely 1,000 feet, the gaps 2,000 feet, and Mount Wash- 

 ington, the only one which rises above 6,000 feet, is still 400 feet 

 below the Black Dome of the Black Mountains. Here then, in all 

 respects, is the culminating region of the vast Appalachian system." 



The eastern chain, or Blue Ridge is still the watershed, and, on 

 the Atlantic slope, gives birth to the Roanoke, Catawba, Broad, 

 Saluda, and Savannah rivers ; while on the other side this area of 

 mountains and plateaus is separated by transverse chains into many 

 deep basins, at the bottom of each one of which runs one of those 

 mountain streams, which are compelled to cut their way to the 

 Tennessee through gaps, gorges, and defiles in the very heart of 

 this mighty chain, giving us some of the most picturesque scenery 



