CHAP. XXI.] 



NEW ZEALAND. 



455 



of plants, no less than in the geological structure of the country, 

 which favour the latter view. But we must on eaij supposition 

 place the union very far back, to -account for the total want of 

 identity between the winged birds of New Zealand and those 

 peculiar to Australia, and a similar want of accordance in the 

 lizards, the fresh-water fishes, and the more important insect- 

 groups of the two countries. From what we know of the long 

 geological duration of the generic types of these groups we 

 must certainly go back to the earlier portion of the Tertiary 

 period at least, in order that there should be such a complete 

 disseverance as exists between the characteristic animals of the 

 two countries ; and we must further suppose that, since their 

 separation, there has been no subsequent union or sufficiently 

 near approach to allow of any important intermigration, even 

 of winged birds, between them. It seems probable, therefore, 

 that the Bampton shoal west of New Caledonia, and Lord 

 Howe's Island further south, formed the western limits of that 

 extensive land in which the great wingless birds and other 

 isolated members of the New Zealand fauna were developed. 

 Whether this early land extended eastward to the Chatham 

 Islands and southward to the Macquaries we have no means of 

 ascertaining, but as the intervening sea appears to be not more 

 than about 1,500 fathoms deep it is quite possible that such an 

 amount of subsidence may have occurred. It is possible, too, 

 that there may have been an extension northward to the 

 Kermadec Islands, and even further to the Tonga and Fiji 

 Islands, though this is hardly probable, or we should find more 

 community between their productions and those of New 

 Zealand. 



A southern extension towards the Antarctic continent at a 

 somewhat later period seems more probable, as affording an 

 easy passage for the numerous species of South American and 

 Antarctic plants, and also for the identical and closely allied 

 fresh-water fishes of these countries. 



The subsequent breaking up of this extensive land into a 

 number of separate islands in which the distinct species of moa 

 and kiwi were developed — their union at a later period, and 

 the final submergence of all but the existing islands, is a pure 



