54 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
for building up the connections between the New Zealand and the South American 
floras must have endured for long periods of geological time; and we do not know how 
far they were aided or hindered by oscillations of climate, or changes in the relative 
level of land and sea. The duration of what may be called the active or colonising period 
of the Antarctic fauna and flora will remain hidden from us until the study of the 
geological record in Antarctica discloses new facts and new ideas. But we do know that, 
sooner or later, a change arrived and a gradual refrigeration of the whole of Antarctica 
took place. During this, the once luxuriant vascular flora slowly perished, or was driven 
northwards; the remnants, with two exceptions, being buried under a perennial ice- 
sheet. What lapse of time was occupied by this refrigeration it is impossible to say; 
nor is there any evidence to show whether it was subject to oscillation, further than it 
is well established that the ice-sheet had a greater development some little time further 
back than it has at present. 
If it be asked what effect antarctic refrigeration has had upon the land areas 
to the north, the reply is that it is known that the whole of the subantarctic zone, 
including the southern portions of New Zealand and South America, everywhere presents 
proof of a parallel refrigeration. This, at the time of its greatest extent, doubtless 
caused much extinction of species, many changes in the composition of the vegetation, 
and probably induced many migrations. The islands of South Georgia, Kerguelen, 
and Macquarie constitute that part of the subantarctic zone that has suffered most 
from Antarctic refrigeration. In the case of South Georgia, most authorities consider 
that the vascular vegetation was entirely destroyed. Dr. Skottsberg explicitly says 
“ It seems hardly possible that the higher flora survived the glacial epoch.” Schimper 
and Schenk argue with great strength and probability that it was entirely destroyed, 
to be replaced, later on, through the agency of pelagic birds. With regard to the 
Kerguelen Group and Macquarie Island, I have already pointed out that they agree 
with South Georgia in their scanty flora, but differ in possessing a few endemic species. 
Here, too, the balance of what evidence we possess is in favour of the belief that the 
whole flora perished, except the endemic species and possibly a few others, of which 
Azorella Selago appears to be the most likely to have survived. 
At the close of the glacial epoch, then, the position in the subantarctic zone 
may be shortly stated as follows :—Macquarie Island had lost its vascular flora except 
two or three grasses; Kerguelen had been almost as badly treated; while in South 
Georgia the whole of the higher flora had perished. When, therefore, a milder climate 
prevailed and the islands became once more capable of supporting a vascular flora, 
only two sources of supply remained—one from Fuegia ; the other from the New 
Zealand area. I have already shown that South Georgia, situated at no great distance 
from Cape Horn, and the Kerguelen Group, both favourably placed in the line of the 
constant westerly winds, have received almost the whole of their flora from Fuegia. 
Macquarie Island, on the other hand, is so much nearer to the New Zealand Subantarctic 
Islands that it was naturally stocked from thence. 
