HuTTON. — The Geological History of Neiv Zealand. 161 



have any record of the ancient faunas and floras that suc- 

 cessively overspread the South Pacific, and it is here that we 

 must look for the principal evidence of the changes that have 

 taken place in the physical geography and climate of this 

 enormous area. Situated at the antipodes of Europe, any 

 cliange of climate there brought about by the shifting of 

 position in the axis of the earth, or by a change in the ec- 

 centricity of its orbit, or by a change in the obliquity of the 

 ecliptic, or by any cosmical change whatsoever, must find its 

 parallel here, and, consequently. New Zealand is to Europe a 

 base of verification for all such-like hypotheses. 



With our present imperfect knowledge it is not surprising 

 that there should be several portions of the geological history 

 of New Zealand on which differences of opinion are held. 

 And I wish at the outset to make it clear that I am about to 

 state my own opinions only, which I do not for a moment 

 suppose are always correct. Geology at its best is an uncer- 

 tain science, depending largely on the accuracy with which 

 gaps in the series of facts are filled up by theory, and in our 

 knowledge of tlie geology of New Zealand there are many and 

 wide gaps. A more detailed and more systematic investiga- 

 tion might, no doubt, make me alter several of the opinions 

 I am going to express. Nevertheless, I think that all the 

 geologists who have examined New Zealand are pretty well 

 agreed upon most points of its geological history. It is only 

 on a few questions that we differ, and we may at least claim 

 to have made the path of investigation easier for those who 

 come after us. With this preliminary qualification, I will 

 now proceed with my subject. 



General Geological Steuctuee. 

 A chain of mountains runs through the South Island from 

 Otago to Nelson, narrow in Westland — where it is called the 

 Southern Alps — but spreading out both in the north and in 

 the south into several ranges. This mountain-range, or oro- 

 graphic axis, however, does not form the tectonic, or struc- 

 tural, axis of the Island — that is, it is not the central line of 

 elevation of the mountains. This line, which is called the 

 " structural axis," lies at their western base along the line 

 of granites in Westland and Nelson ; so that the moun- 

 tain-range is only the eastern half of a huge geanticlinical 

 arrangement of contorted rocks, the western half having 

 been washed away by the heavy rains which fall upon 

 that side, and which must have fallen for a very long 

 time to have produced so great an effect. As these rains 

 are due to the westerly winds sweeping over a large ocean, 

 we have here a proof that moisture-laden westerly winds 

 have predominated in these latitudes for a very long time. 

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