50 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
much less. This submarine plateau stretches for some little distance to the east of the 
Chatham Islands, or more than 500 miles from New Zealand, before water with a 
greater depth than 1,000 fathoms is obtained. It then sinks rapidly until depths of 
over 2,500 fathoms are reached. Going south from Auckland Island, and within 
100 miles of it, a depth of 2,430 fathoms was recorded by the “ Aurora.” These 
sudden dips from comparatively shallow water into the enormous depths which surround 
the greater part of New Zealand may be reasonably taken as evidence of a “ continental 
shelf,” indicating the former boundary of a “ Greater New Zealand” in the far remote 
past. 
The extent to which the New Zealand Subantarctic Islands have been glaciated 
in recent times has not been definitely settled, although there can be no doubt that 
they have been subjected to a moderately severe glaciation, but probably not sufficient 
to produce a continuous ice-sheet, although quite ample to cause great climatic and 
biologic changes. 
The present climate can be best described as cold, windy, foggy or cloudy, and 
rainy. Like all portions of the subantarctic zone, it is mainly remarkable for the small 
diurnal and annual variation. In Macquarie Island the mean temperature for the 
year can be given as 40-7°, and the mean range between summer and winter as 5-3°. 
In Campbell Island the mean temperature is 44-5°, and the mean range between 
summer and winter 10-0°, while the rainfall is 53-8 inches. 
As might be predicted from the more northerly latitude and less severe climate, 
the flora of the New Zealand Subantarctic Islands is much more copious than that of 
the islands previously treated of. The total number of species recorded is 194, of which 
53 are endemic. For the first time we see a true ligneous vegetation. Many orchids 
appear, as also representatives of the genera Veronica, Myosotis, Gentiana, and others. 
The endemic species are greatly increased in number, and what is still more important, 
include genera or groups of a distinctive character, which can only be looked 
upon as ancient and long-isolated types. Elsewhere I have shown that the flora 
contains three main elements, which may be particularised as follows :—First, an 
endemic element, consisting of two parts, one comprising plants like Stilbocarpa, 
Pleuropliyllum, the Ionopsis section of Celmisia, &c., which are probably the remnants 
of an ancient flora, which ages ago occupied the islands; the other consisting of species 
closely allied to plants at present living in New Zealand. Second, an element which 
includes the greater part of the flora, and which is composed of species at present 
living in New Zealand proper, and which must be looked upon as immigrants of recent 
date. Third, a Euegian element, also consisting of two parts, one much older than 
the other, and composed of such genera as Colobanthus, Abrotanella, Phyllachne, 
Rostkovia, &c., the other including plants living in both countries at the present time, 
as Cardamine glacialis, Callitriclie antarctica, Tillcea moschata, Nertera depressa, Carex 
trifida, &e. 
