Fauna and Flora of New Zealand. 105 



from the Eocene to the Pliocene period, that it was submerged 

 before the Pleistocene, and that we now see remnants of it in 

 Graham's Land, Enderby Land, and Victoria Land. During 

 the time this land existed it is possible that colder and warmer 

 periods may have occurred when the eccentricity of the earth's 

 orbit was great ; but this I consider a mere speculation un- 

 supported by any evidence, for changes of climate are not 

 required to account for any of the phenomena. 



It is evident from what has been said, that the north-tem- 

 perate plants came to New Zealand before the Pleistocene 

 period, and consequently they could not have migrated along 

 the Andes during the glacial epoch of Europe. Either there 

 have been many other glacial epochs, or else glacial epochs 

 are not necessary for this meridional migration. I believe 

 the latter to be the more correct view, because there is no 

 evidence of glacial epochs in the southern hemisphere, and 

 because the physical changes necessary to elevate or depress 

 a chain of mountains for a few thousand feet are far less than 

 those which are now acknowledged by nearly all geologists 

 to be necessary for bringing about profound alterations in 

 climate over immense districts of the globe. No one has as 

 yet been sufficiently bold to advocate a glacial climate in New 

 Guinea and Borneo, and yet the evidence of plant migration 

 from Asia into Australia is as strong as that for a migration 

 along the Andes ; and, as it is very unlikely that an eleva- 

 tion of the Indian archipelago coincided in time with the 

 glacial epoch of Europe, so it is very unlikely that glacial 

 epochs are necessary for the meridional migration of plants. 

 It follows that if plants have travelled from the northern 

 hemisphere to Australia and New Zealand, some must have 

 passed through the tropics and into temperate climates a^ain 

 without undergoing any change of generic importance. In 

 the same way the subtropical 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 subtropical 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 summarize in as few words as possible the re- 

 sults we have arrived at in both addresses. New Zealand 

 which formerly existed as the southern part of a continent 



