CHAPTER XIV. 



THE PHYSICAL GEOGRAPHY AND GEOLOGY OF THE AMAZON 



VALLEY. 



The basin of the Amazon surpasses in dimensions that of any 

 other river in the world. It is entirely situated in the Tropics, 

 on both sides of the Equator, and receives over its whole 

 extent the most abundant rains. The body of fresh water 

 emptied by it into the ocean, is therefore far greater than that 

 of any other river ; not only absolutely, but probably also 

 relatively to its area, for as it is almost entirely covered by dense 

 virgin forests, the heavy rains which penetrate them do not 

 suffer so much evaporation as when they fall on the scorched 

 Llanos of the Orinooko or the treeless Pampas of La Plata. 

 For richness of vegetable productions and universal fertility 

 of soil it is unequalled on the globe, and offers to our notice 

 a natural region capable of supporting a greater population, 

 and supplying it more completely with the necessaries and 

 luxuries of life, than any other of equal extent. Of this 

 wonderful district we will now describe the principal physical 

 peculiarities. 



From about 4 north latitude to 20 south, every stream that 

 flows down the eastern slope of the Andes is a tributary of the 

 Amazon. This is as if every river, from St. Petersburg to 

 Madrid, united their waters into one mighty flood. 



The Maranon, which is generally considered the main 

 stream of the Amazon, deserves that title on several accounts. 

 It rises to the westward of all the other great tributaries, and it 

 receives all the waters which flow nearest to the Pacific, and 

 most remote in a direct line from the mouth of the river. It 

 flows for a considerable distance in the most westerly valley of 

 the Andes, separated by one range only from the Pacific, and 

 at the point where it breaks through the eastern chain of the 



