THE ORIGIN OF THE FAUNA AND FLORA OF NEW ZEALAND. 273 
the northern hemisphere to Australia and New Zealand, some 
must have passed through the tropics and into temperate climates 
again without undergoing any change of generic importance. 
In the same way the sub-tropical and temperate plants of New 
Zealand have invaded the snow-clad regions of the South Island, 
and have become alpines, without undergoing any generic 
change. And just as the occurrence of Alpine species of sub- 
tropical genera does not prove that the tops of our mountains 
are warm, so the occurrence of species of tropical genera in the 
European miocene does not necessarily prove it to have been 
tropical in temperature. As these plants migrated towards the 
equator they would gradually accustom themselves to altered 
conditions without losing the marks of their affinities. 
I will now summarise in as few words as possible the results we 
have arrived at in both addresses. New Zealand, which formerly 
existed as the southern part of a continent extending through 
Australia to India, was isolated from Australia towards the close 
of the jurassic period,* but was attached to a South Pacific con- 
tinent and received a stream of immigrants from the north. 
None arrived from the south because Fuegia was not then in ex- 
istence. In the upper cretaceous the land shrank to a size 
considerably smaller than at present. In the eocene, elevation 
took place and New Zealand extended outwards in all directions, 
but remained isolated trom other lands. Plants and animals 
came in both from the north and from the south. In the 
oligocene and miocene periods New Zealand was, except for a 
short interval, a cluster of islands, but was upraised once more, 
and obtained more immigrants from north and south during the 
pliocene ; after which subsidence occurred, and the land through- 
out the South Island and southern half of the North Island sank 
considerably below its present level, to be again elevated during 
the pleistocene period. 
It has been objected that we have no right to infer that 
because elevation or subsidence can be proved to have occurred 
in one particular district of the earth’s surface, therefore this 
elevation or subsidence extended over neighbouring areas. But 
the more the geology and paleontology of large geographical 
regions, like North America or Europe are studied, the more 
clearly we see that subterranean movements have affected large 
regions simultaneously, or nearly simultaneously, and that the 
local deviations from uniformity are comparatively small. So 
it comes about that we have in each large geographical area a 
series of rock systems which are nearly synchronous over the 
whole area, although not synchronous with those in other and 
distant areas. I think that our knowledge of the paleontology 
of Australasia is already sufficient to shew that we have here also 
another of those large geographical areas which, when viewed on 
a large scale, has been moved uniformly ; and therefore that the 
rock systems of New Zealand can be parallelled with those of 
* I need hardly say that I use these terms with very wide margins, 
