258 JOURNAL OF SCIENCE 
to exterminate throughout New Zealand all but the more cold- 
loving species of plants and animals.* But we find, as I showed 
in my last address, that the principal part of our sub-tropical 
fauna and flora was introduced before the miocene period, and 
has flourished ever since. It has, however, been lately suggested 
that the survival of our terrestrial fauna and flora through a cold 
glacial epoch may have been due to the sea standing at that time 
at a lower level than at present, and so affording room for the 
plants and animals to retire to.* No doubt Sir W. Thomson 
has calculated that the ice-cap covering northern Europe and 
America during the glacial epoch might have caused, by its 
attraction, a rise of the ocean of some 380 feet at the North 
Pole, and a lowering to the same extent at the South Pole,t and 
that the amount of water taken from the ocean t> form the ice 
might have lowered the level 120 feet all over the world. Thus 
reducing the rise at the North Pole to perhaps 260 feet, and in- 
creasing the fall at the South Pole to 500 feet at most. That is 
a fall of about 300 feet in the latitude of New Zealand. But this 
fall would occur when the ice-cap was on the northern hemis- 
phere. If the ice-cap shifted to the south the ocean would stand 
about 70 feet Azgher, instead of lower, round our islands, and con- 
sequently there would be no low-lying land for the plants and 
animals to retreat to. It is no doubt true, as mentioned by Dr. 
A. Geikie, that the pleistocene raised beaches and shore deposits 
of New Zealand indicate a greater elevation of the southern than 
of the northern parts of the country,t but our knowledge on this 
subject is not yet sufficiently exact to enable us to draw any 
conclusions. At present it appears as if these deposits indicated 
an elevation of 10 feet near Auckland, rising to 800 in Canter- 
bury and Otago, and if this be true the pleistocene submergence 
could hardly be due to displacement of the sea caused by the 
attraction of an ice-cap on the South Pole, for the rise is too 
great and too rapid. 
That the former extension of our glaciers was not caused by 
a cold period is, I believe, acknowledged by all New Zealand 
geologists, and also bythe late Dr. von. Hochstetter.§ Instead of 
a glacial epoch, four other hypotheses have been put forward to 
account for the phenomena:—(1.) The first is the elevation of 
the land, in combination with a more plateau-like form of the 
mountains, which would thus collect more snow.|| (2.) The 
* Trans, N.Z, Institute, viii. p. 385. 
* Dr. v. Haast, Geol. of Canterbury and Westland, p. 381. 
‘+ Archdeacon Pratt and the Rev. O. Fisher make it more, but only on the supposi- 
tion that the interior of the earth is fluid. Mr, Belt’s calculations on this subject 
are of no value, as the enormous simultaneous ice-caps supposed by him to have 
occurred, are quite incredible. 
tText-book of Geology, p. 280 Dr. von Haast, however, who is the authority 
quoted by Dr. Geikie, is of the opposite opinion. He says ‘*‘One fact however is 
certain—namely, that the land in post-pliocene times in the northern part of the 
province [of Canterbury] along the east coast stood at a lower level than at the cen- 
tral and southern portions.” Geol. Cant., p. 366. 
§ New Zealand (1867), p. 505. 
Hector, Geological Expedition to the West Coast of Otago, Otago Provincial 
Gazette, 5th Nov., 1863 ; and Trans. N.Z, Institute, VI., p. 374 (1873). 
