MOUNTAIN RANGES. 



207 



aili ranges, which divide the country into three 

 distinct natural sections. These may be called the 

 Atlantic Slope, the Mississippi Valley, and the Pa- 

 cific Slope. The Alleghany or Appalachian range 

 is remarkable chiefly for its length, extending from 

 Canada on the north to Alabama on the south, a 

 distance of more than 1200 miles ; while its mean 

 average height is not more than 2500 feet, and more 

 than half of this consists of the height of the mount- 

 ain ridges above their bases, and the other, of the 

 height of the adjoining country above the sea. 

 About midway between the Atlantic and the Mis- 

 sissippi hes a vast table-land, extending from the 

 rivers of Alabama and Mississippi to the great 

 lakes and the St. Lawrence, occupying the western 

 part of the Atlantic states, and the eastern part of 

 the adjoining states of the Mississippi Valley. 

 Along this table-land extend five or six parallel 

 mountain chains, of which the most remarkable are 

 the Blue Ridge, the Alleghany Ridge, the Wickany, 

 and the Cumberland Mountains. The White Mount- 

 ains of New-Hampshire, which are usually consid- 

 ered as a prolongation of the Blue Ridge, contain 

 some of the loftiest summits east of the Mississip- 

 pi, Mount Washington being 6428 feet above the 

 sea; the Black Mountain, in North Carolina, which 

 IS in the range of the Blue Ridge, is ascertained to 

 be 6476 feet in height, while the highest point of 

 the Alleghany is not over 3000 feet above the sea. 



The Rocky Mountains have been sometimes call- 

 ed the Andes of North America, or the Chippeway- 

 an system ; and they extend from the Isthmus of 

 Panama, parallel with the Pacific, almost to the 

 Arctic Sea ; having an average height of 8000 feet 

 above the ocean, or 5000 above the level of their 

 base. Their highest summit has usually been 

 computed at about 12,000 feet ; though Professor 



* Outlines of Geology, p. 13. 



