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 any 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 
