312 PHYSIOGRAPHY [chap. 



which have a more or less north-and-south direction, take 

 their rise in Mexico and in the western territories of the 

 United States, from this table-land, or from its escarpments. 

 Just as the east-and-west line of mountains in Eurasia, is 

 nearer to the south than to the north coast ; so the north and 

 south axis of America is nearer to the west than to the east 

 coast. Hence, the western slope of the American conti- 



"W 



Fig. 93. — Diagrammatic seciion across North America. 



nent is very abrupt, while the eastern side is carried 

 gradually down to great plains, which are drained by some 

 of the noblest streams in the world ; such as the Mississippi 

 in North, and the Amazon, in South, America. If then, a 

 section were made across North America, from west to east, 

 it would present an appearance something like that repre- 

 sented diagrammatically in Fig. 93. Here, it is seen that 



a b 



Fig. 94. — Diagrammatic section across Smth America. 



there is a sharp rise, from the Pacific coast on the west, to 

 the Washington range, a; and, thence, to the summit of the 

 parallel chain of the Rocky mountains, b. From the 

 eastern slope of the Rocky mountains, the section runs 

 across the basin of the Mississippi, but rises again before 

 reaching the eastern coast. This rise, d, represents the 

 Appalachians, which form a range of mountains running 



