70 THE ORIGIN OF AUSTRALIA 
living flora. On the other hand, it shows the mixed character 
of the Tertiary Floras in Europe, the Arctic Regions, North 
America, and probably all the Tertiary Floras. It has 
also much more similarity to the Tertiary Floras at present 
known than to the existing flora of Australia. The charac- 
teristic plants of Australia are but feebly represented.” 
54. Space will not permit of details: for this my 
forthcoming book must be consulted. But this last con- 
clusion, which I have italicised, enables us to put the botanical] 
problem as never before. How comes it (1) that the present 
Flora is so utterly different from the Tertiary flora, and (2) 
how comes it that the feeblest part of the Australian Tertiary 
Flora has developed into the rich and unique Flora of the 
present ? An answer will be given in the sequel. 
VIII. THE PRESENT FAUNA. 
55. It is chiefly upon the fauna of Australia that the 
idea has been founded that ours is an arrested continent, 
in which owing to long isolation, and consequent immunity 
from competition, have been preserved forms of life that else- 
where have succumbed or become modified in the struggle’ 
for existence. Among molluscs our Brachiopods, among 
fishes our Ceratodus and Cestraceon, for example, and 
above all our Marsupials are pointed to as lingering strains 
of the Mesozoic age—and in the pretty, banded, Myrme- 
cobius we are asked to see the echo of the Microlestes that 
wandered by the waterside in old England when the Oolites 
were forming. No one ever seems to have doubted this, 
yet I believe I shall prove it to be an entirely erroneous 
assumption. 
56. I cannot stop to work out the whole of our fauna. 
That must be recorded elsewhere. But as our Marsupials 
afford the strongest argument for the prevailing opinion, 
we will take them as a test. The assumption is based 
upon the fact that in Triassic and Jurassic times the only 
known mammals were smal! creatures which have been placed 
among the Marsupialia. Also that the aplacental charac- 
ter of these mammals shows that they are of very low— 
indeed the lowest—type of mammal. Let us see how far 
these assumptions are borne out by facts. 
