CHAP. XXII.] 
THE FLORA OF NEW ZEALAND. 
4G5 
able to receive immigrants from the former, at a later period, 
and in a more or less fragmentary manner. 
If we examine the geological map of Australia (given in 
Stanford’s Compendium of Geography and Travel, volume 
“ Australasia”) , we shall see good reason to conclude that the 
eastern and the western divisions of the country first existed as 
separate islands, and only became united at a comparatively 
recent epoch. This is indicated by an enormous stretch of 
Cretaceous and Tertiary formations extending from the Gulf of 
Carpentaria completely across the continent to the mouth of the 
Murray River. During the Cretaceous period, therefore, and 
probably throughout a considerable portion of the Tertiary 
epoch, 1 there must have been a wide arm of the sea occupying 
this area, dividing the great mass of land on the west — the true 
seat and origin of the typical Australian flora — from a long but 
narrow belt of land on the east, indicated by the continuous 
mass of Secondary and Palaeozoic formations already referred to 
which extend uninterruptedly from Tasmania to Cape York. 
Whether this formed one continuous land, or was broken up 
into islands, cannot be positively determined ; but the fact 
that no marine Tertiary beds occur in the whole of this area, 
renders it probable that it was almost, if not quite, continuous, 
and that it not improbably extended across to what is now 
New Guinea. At this epoch, then (as shown in the accom- 
panying map), Australia would consist of a very large and 
fertile western island, almost or quite extra-tropical, and ex- 
tending from the Silurian rocks of the Flinders range in South 
Australia, to about 150 miles west of the present west coast, 
and southward to about 350 miles south of the Great Australian 
Bight. To the east of this, at a distance of from 250 to 400 
miles, extended in a north and south direction a long but 
1 From an examination of the fossil corals of the South-west of Victoria, 
Professor P. M. Duncan concludes — “that, at the time of the formation of 
these deposits the central area of Australia was occupied by sea, having 
open water to the north, with reefs in the neighbourhood of Java.” The 
age of these fossils is not known, but as almost all are extinct species, and 
some are almost identical with European Pliocene and Miocene species 
they are supposed to belong to a corresponding period. ( Journal of Geol . 
Soc., 1870.) 
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