Physical Geography. 23 



Africa by a deep channel three hundred miles wide, possesses 

 so many peculiar features as to indicate separation at a very 

 remote antiquity, or even to render it doubtful whether the 

 two countries have ever been absolutely united. 



Returning now to the Malay Archipelago, we find that all 

 the wide expanse of sea which divides Java, Sumatra, and 

 Borneo from each other, and from Malacca and Siam, is so 

 shallow that ships can anchor in any part of it, since it rarely 

 exceeds forty fathoms in depth ; and if we go as far as the 

 line of a hundred fathoms, we shall include the Philippine Isl- 

 ands and Bali, east of Java. If, therefore, these islands have 

 been separated from each other and the continent by subsi- 

 dence of the intervening tracts of land, we should conclude 

 that the separation has been comparatively recent, since the 

 depth to which the land has subsided is so small. It is also 

 to be remarked that the great chain of active volcanoes in 

 Sumatra and Java furnishes us wnth a sufiicient cause for such 

 subsidence, since the enormous masses of matter they have 

 thrown out would take away the foundations of the surround- 

 ing district ; and this may be the true explanation of the often- 

 noticed fact that volcanoes and volcanic chains are always 

 near the sea. The subsidence they produce around them will, 

 in time, make a sea, if one does not already exist. 



But it is when we examine the zoology of these covmtries 

 that we find what we most require — evidence of a very strik- 

 ing character that these great islands must have once formed 

 a part of the continent, and could only have been separated at 

 a very recent geological epoch. The elephant and tapir of 

 Sumatra and Borneo, the rhinoceros of Sumatra and the allied 

 species of Java, the wild cattle of Borneo and the kind long 

 supposed to be pecuHar to Java, are now all known to inhabit 

 some part or other of Southern Asia. None of these large 

 animals could possibly have passed over the arms of the sea 

 which now separate these countries, and their presence plainly 

 indicates that a land communication must have existed since 

 the origin of the species. Among the smaller mammals, a 

 considerable portion are common to each island and the con- 

 tinent ; but the vast physical changes that must have occurred 

 during the breaking up and subsidence of such extensive re- 

 iiions have led to the extinction of some in one or more of the 



