CHAP. XII] THE AUSTRALIAN REGION. 447 
Sandwich Islands, by the peculiar plants which are found on 
their mountains. The peak of Teneriffe produces no Alpine 
plants of European type, and this has been considered to prove 
that it has been always isolated ; whereas the occurrence of North 
Temperate forms on the mountains of Java, accords with other evi- 
dence of this island having once formed part of the Asiatic con- 
tinent. Now on the higher summits of the Sandwich Islands, 
nearly 30 genera of Arctic and North Temperate flowering plants 
have been found. Many of these occur also in the South Temperate 
zone, in Australia or New Zealand; but there are others which 
seem plainly to point to a former connection with some North 
Temperate land, probably California, as a number of islets are 
scattered in the ocean between the two countries. The most 
interesting genera are the following :—Silene, which is wholly 
North Temperate, except that it occurs in 8. Africa; Vucza, 
also North Temperate, and m South Temperate America; 
Fragaria, with a similar distribution; Aster, widely spread 
ins America, otherwise North Temperate only ; Vacciniwm, 
wholly confined to the northern hemisphere, in cold and 
temperate climates. None of these are found in Australia or 
New Zealand; and their presence in the Sandwich Islands 
seems clearly to indicate a former approximation to North 
Temperate America, although the absence of any American 
forms of vertebrata renders it certain that no actual land con- 
nection ever took place. 
Recent soundings have shown, that the Sandwich Islands 
rise from asea which is 3,000 fathoms or 18,000 feet deep; 
while there is a depth of at least 2,000 fathoms all across to 
California on one side, and to Japan on the other. Between 
the Fiji Islands, New Caledonia, the Solomon Islands, and 
Australia, the depth is about 1,300 fathoms, and between Sydney 
and New Zealand 2,600 fathoms; showing, in every case, a 
general accordance between the depth of sea and the approxi- 
mation of the several faunas. In a few more years, when it is 
to be hoped we shall know the contour of the sea-bottom better 
than that of the continents, we shall be able to arrive at more 
definite and trustworthy conclusions as to the probable changes 
