chap, i.] PHYSICAL GEOGRAPHY. 27 



islands, again, though in such close proximity as Bali and 

 Lombock, might each exhibit an almost unmixed sample 

 of the productions of the continents of which they had 

 directly or indirectly once formed a part. 



In the Malay Archipelago we have, I believe, a case 

 exactly parallel to that which I have here supposed. We 

 have indications of a vast continent, with a peculiar fauna 

 and flora, having been gradually and irregularly broken 

 up; the island of Celebes probably marking its furthest 

 westward extension, beyond which was a wide ocean. At 

 the same time Asia appears to have been extending its 

 limits in a south-east direction, first in an unbroken mass, 

 then separated into islands as we now see it, and almost 

 coming into actual contact with the scattered fragments of 

 the great southern land. 



From this outline of the subject, it will be evident how 

 important an adjunct Natural History is to Geology ; not 

 only in interpreting the fragments of extinct animals 

 found in the earth's crust, but in determining past changes 

 in the surface which have left no geological record. It is 

 certainly a wonderful and unexpected fact, that an accurate 

 knowledge of the distribution of birds and insects should 

 enable us to map out lands and continents which dis- 

 appeared beneath the ocean long before the earliest tra- 

 ditions of the human race. Wherever the geologist can 

 explore the earth's surface, he can read much of its past 



