NATURAL HISTORY OF CREATION. 189 



country, tlio inarsli round a salt spriug far inland, or an 

 island placed far apart in the ocean — appropriate plants 

 liave there taken up their abode. But the torrid zone 

 divides the two temperate regions from each other by the 

 space of more than forty-six degrees, and the toriid and 

 temperate zones together form a much broader line of 

 division between the two Arctic regions. The Atlantic 

 and Pacific Oceans, and the Persian Gulf, also divide the 

 various portions of continent in the torrid and temperate 

 zones from each other. Australia is also divided by a 

 broad sea from the continent of Asia. Thus there are 

 various portions of the earth separated from each other 

 in such a way as to preclude anything like a general 

 communication of the seeds of their respective plants 

 towards each other. Hence arises an interesting ques- 

 tion — Are the plants of the various isolated regions 

 which enjoy a parity of climate and other conditions, 

 identical or the reversed The answer is — that in such 

 regions the vegetation bears a general resemblance, but 

 the species are nearly all difterent, and there is even, in 

 a considerable measure, a diversity of families. 



The general facts have been thus stated : in the Arctic 

 and Antarctic regions, and in those parts of lower lati- 

 tudes, which, from their elevation, possess the same cold 

 climate, there is always a similar or analogous vegeta- 

 tion, but few species are common to the various situa- 

 tions. In like manner, the intertropical vegetation of 

 Asia, Africa, and America, ai-e specifically difi'erent, 

 though generally similar. The southern region of 

 America is equally diverse from that of Afiica, a 

 country similar in clime, but separated by a vast extent 

 of ocean. The vegetation of Australia, another region 

 similarly placed in respect of clime, is even more 

 peculiar. These facts are the more remarkable when 



