54 
PHYSICAL GEOGRAPHY. 
animal kingdom deserves a passing notice. It is in 
the torrid zone that we find birds of the largest size 
and gayest plumage ; the largest and most power- 
ful reptiles, as the crocodile, the alligator, and the 
boa constrictor ; quadrupeds of immense size and 
strength, as the elephant, the rhinoceros, the lion, 
the tiger, and the giraffe. So also is the ocean 
distinguished in tropical climates by the production 
of shells, corals, and fishes peculiar to hot regions. 
There, too, vegetable productions attain their great- 
est luxuriance and variety ; the palm, the sugar- 
cane, the coffee-tree, and the innumerable spice- 
bearing trees and shrubs, exhibit the most luxuriant 
types of vegetable life, the richest fruits and the 
most beautiful blossoms. As we go north this lux- 
uriance disappears; animal and vegetable existence 
appear in less variety and in comparatively dimin- 
utive forms ; and when we reach the polar circles, 
we are struck with the scantiness of animated crea- 
tion, which is there represented by the reindeer and 
the polar bear upon the land, the whale and the me- 
dusae on which it feeds in the ocean, while a few 
mosses and lichens compose the vegetation upon the 
frozen surface. 
Height of mountains. — A large portion of the 
earth's surface is but slightly elevated above the 
ocean, especially upon the banks of great rivers and 
in extensive districts along the seashore. This is 
particularly the case in Holland, Northern Germa- 
ny, and a large part of Russia ; also in India and 
China, and other parts of Asia, and the valley of the 
Mississippi in North America. The highest land 
in Asia is the Himalaya Mountains, which rise to 
an elevation of more than 28,000 feet, or more than 
five miles above the level of the sea. On the island 
of Great Britain, the highest elevations are the 
Welsh Mountain, Snowdon, which rises to the 
height of 3571 feet, and Ben Nevis in Scotland, 
which is 4365 feet high. The highest land in Ire- 
