348 DARWINISM chap. 



land.^ Madagascar is the only island on the globe "with a fairly- 

 rich mammalian fauna which is separated from a continent by 

 a depth greater than a thousand fathoms ; and no other island 

 presents so many peculiarities in these animals, or has pre- 

 served so many lowly organised and archaic forms. The 

 exceptional character of its productions agrees exactly with its 

 exceptional isolation by means of a very deep arm of the sea. 

 New Zealand possesses no known mammals and only a 

 single species of batrachian ; but its geological structure is 

 perfectly continental. There is also much evidence that it 

 does possess one mammal, although no specimens have been 

 yet obtained.- Its reptiles and birds are highly peculiar and 

 more numerous than in any truly oceanic island. Now the 

 sea Avhich directly separates Ncav Zealand from Australia is 

 more than 2000 fathoms deep, but in a north-west direction 

 there is an extensive bank under 1000 fathoms, extending to 

 and including Lord Howe's Island, while north of this are 

 other banks of the same depth, approaching towards a sub- 

 marine extension of Queensland on the one hand, and New 

 Caledonia on the other, and altogether suggestive of a land 

 union "with Australia at some very remote period. Now the 

 jDeculiar relations of the New Zealand fauna and flora with 

 those of Australia and of the tropical Pacific Islands to the 

 northward indicate such a connection, probably during the 

 Cretaceous period ; and here, again, we have the exceptional 

 dejDth of the dividing sea and the form of the ocean bottom 

 according well with the altogether exceptional isolation of 

 New Zealand, an isolation which has been held by some 

 naturalists to be great enough to justify its claim to be one 

 of the primary Zoological Regions. 



Tlie Teachings of tlie Thousand-Fathom Line. 



If now we accept the annexed map as showing us approxi- 

 mately how far beyond their present limits our continents may 



^ For a full account of the peculiarities of the Madagascar fauna, see my 

 Island Life, chap. xix. 



- See Island Life, p. 446, and the whole of chaps, xxi. xxii. More 

 recent soundings have shown that the Map at p. 443, as well as that of the 

 Madagascar group at p. 387, are erroneous, the ocean around Norfolk Island 

 and in the Straits of Mozambique being more than 1000 fathoms deep. 

 The general argument is, however, unaffected. 



I 



