Continental and Island Life [pp. 1-29]

COANTINENTAL AND ISLAND LIFE.
have evidence in the Madeira group, not of modification, but of
unchanged survival of Tertiary species long since extinct in
Europe. May we not infer that the same was the case in the
Azores? These results are certainly very striking when we consider how long the Azores must have existed as islands, how very
rarely animals, and especially pairs of animals, must have reached
them, and how complete has been the isolation of these animals
and how peculiar the conditions to which they have been subjected in their island retreat.
Other oceanic islands present great varieties of conditions,
but leading to similar conclusions. Some, as the Bermudas,
seem to have been settled in very modern times with animals
and plants nearly all identical with those of neighboring countries. Others, like St. Helena, are occupied apparently with old
settlers, which may have come to them in early Tertiary or even
in Secondary periods, which have long since become extinct on
the continents, and whose nearest analogues are now widely scattered over the world. Islands are therefore places of survival
of old species-special preserves for forms of life lost to the continerits. One of the most curious of these, according to Wallace,
is Celebes, which seems to be a surviving fragment of Miocene
Asia, which, tho so near to that continent, has been sufficiently
isolated to preserve its old population during all the vast lapse
of time between the middle Tertiary and the present period.
This is a fact which gives to the oceanic islands the greatest
geological interest, and induces us to look in their actual faunae
and florae for the representatives of species known on the mainland only as fossils. It is thus that we look to the marsupials
of Australia as the nearest analogues of those of the Jurassic of
Europe, and that we find in the strange barramunda of its
rivers the only survivor of a group of fishes once widely distributed, but which has long since perished elsewhere.
Perhaps one of the most interesting examples of this is furnished by the Galapagos Islands, an example the more remarkable that no one who has read in Darwin's fascinating "Journal" the description of these islands, can have failed to perceive
that the peculiarities of this strange archipelago must have been
prominent among the facts which first planted in his mind the
germ of that theory of the origin of species which has since grown
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