n their vegetation and animal
life. The western and more ancient land already possessed, in its main
features, the peculiar Australian flora, and also the ancestral forms of
its strange marsupial fauna, both of which it had probably received at some
earlier epoch by a temporary union with the Asiatic continent over what is
now the Java sea. Eastern Australia, on the other hand, possessed only the
rudiments of its existing mixed flora, derived from three distinct sources.
Some important fragments of the typical Australian vegetation had reached
it across the marine {498} strait, and had spread widely owing to the soil,
climate and general conditions being exactly suited to it: from the north
and north-east a tropical vegetation of Polynesian type had occupied
suitable areas in the north; while the extension southward of the Tasmanian
peninsula, accompanied, probably, as now, with lofty mountains, favoured
the immigration of south-temperate forms from whatever Antarctic lands or
islands then existed. This supposition is strikingly in harmony with what
is known of the ancient flora of this portion of Australia. In deposits
supposed to be of Eocene age in New South Wales and Victoria fossil plants
have been found showing a very different vegetation from that now existing.
Along with a few Australian types--such as Pittosporum, Knightia, and
Eucalyptus, there occur birches, alders, oaks, and beeches; while in
Tasmania in freshwater limestone, apparently of Miocene age, are found
willows, alders, birches, oaks, and beeches,[132] all except the latter
genus (Fagus) now quite extinct in Australia.[133] These temperate forms
probably indicate a more oceanic climate, cooler and moister than at
present. The union with Western Australia and the establishment of an arid
interior by modifying the climate may have led to the extinction of many of
these forms and their replacement by special Australian types more suited
to the new conditions.

At this time the marsupial fauna had not yet reached this eastern land,
which was, however, occupied in the north by some ancestral struthious
birds, which had entered it by way of New Guinea through some very ancient
continental extension, and of which the emu, the cassowaries, the extinct
Dromornis of Queensland, and the moas and kiwis of New Zealand, are the
modified descendants.

_The Origin of the Australian Element in the New Zealand Flora._--We have
now brought down the history of Australi