§ 6. GEOGRAPHY OF ANIMALS AND PLANTS. 33 



surface of the globe is fit for the habitation of man and 

 terrestrial animals.* The area of the Pacific Ocean alone, 

 is estimated to be equal to the entire surface of the dry land. 

 The distribution of the land is exceedingly irregular, the 

 greater portion being situated in the northern hemisphere, 

 as a reference to a terrestrial globe, or a map of the world, 

 will clearly demonstrate. 



In a geological point of view, dry land is that portion 

 of the earth's crust which is now above the level of the 

 water, beneath which it may again disappear ; and from 

 accurate calculations it is proved, that the whole of the 

 materials composing the present land might be distributed 

 over the bed of the ocean, in such manner that the surface 

 of the globe would present an uninterrupted sheet of water; 

 thus we perceive that every imaginable distribution of land 

 and water may have taken place, at different periods, in 

 the earlier ages of our planet. 



6. Geographical distribution of animals and plants. 

 — The investigation of the laws which govern the geo- 

 graphical distribution of animals and vegetables is highly 

 interesting; but as my limits compel me to be brief, I must 

 refer you to Mr. Lyell's " Principles of Geology" for a full 

 consideration of the subject. It will be sufficient for our pre- 

 sent purpose to state, that although it might have been 

 expected, all other circumstances being equal, that the same 

 animals and plants would be found in places of like climate 

 and temperature, this identity of distribution does not exist. 

 When America was first discovered, the indigenous quad- 

 rupeds were all dissimilar to those of the Old World. The 

 elephant, rhinoceros, hippopotamus, giraffe, camel, horse, 

 buffalo, lion, tiger, &c. were not met with on the new con- 

 tinent ; while many of the American mammalia, as the 

 llama, jaguar, coati, sloth, &c. were unknown in the old. 



* Bakewell's Geology. 



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