376 TERRESTRIAL MOUNTAIN RANGES. 



and yet it remains a question whether this vast lapse of 

 geological time would be sufficient to account for the 

 differences which are found to exist between the plants 

 and animals on the Australian continent and those of 

 Asia for variations are known to be always in progress, 

 and therefore the longer the period that has elapsed 

 since lands were thus separated from each other, the 

 greater would be the probable divergence. Whole 

 races of beings on one side for instance may become 

 extinct, while on the other they may perhaps survive, 

 but in a modified form. New species may also gradually 

 be evolved these however are speculations which are 

 more properly dealt with in works specially devoted 

 to the consideration of this class of subjects. 



Leaving now the question of submarine mountains, 

 and all similar considerations concerning which very 

 little is really known beyond the mere fact of their 

 existence, we approach the main subject matter of this 

 section, namely the great terrestrial mountain ranges 

 as they now exist in different parts of the world, 

 rising above the general level of the surrounding 

 land. 



It would, we think, be unnecessary to enumerate a list 

 of them : we propose therefore merely to refer to them 

 in general terms, reserving certain sections of them for 

 more particular notice hereafter, where that may appear 

 to be desirable. 



Let us begin with the mountains of America, as 

 being much less complicated than the numerous ranges 

 of the Eastern Hemisphere. A glance at the map shows 

 that a vast range extends almost without a break, 

 from the far north to the extreme south, right along 

 the whole of the western sea-board of America. This 



