Page:A sketch of the physical structure of Australia.djvu/102

90 as dry land during the oolitic and cretaceous periods, if so, is it not possible that its present fauna and flora may be in some way the descendants and representatives of the fauna and flora that in the oolitic period was common to the whole earth? We have in our oolitic rocks in Europe fossil trigoniæ and other shells, fossil plants allied to zamiæ and cycas, and a fossil marsupial animal. As is well known to every one, Australia is the head quarters of the marsupial animals of the present day, zamiæ and cycadeæ abound in its forests, growing in the burnt up sandy plains, covered with ironstone pebbles under lofty slender leaved eucalypti, and the Australian coasts are the only localities where trigoniæ are found now living in the world. I believe the parallelism of the living flora and fauna of Australia, and that fossil in the oolites might be carried still farther, if my knowledge of each were greater and more exact: but in what has been said above, we find that there is at least a generic or family resemblance in some of the land animals, some of the land plants, and some of the animals of the sea.

We have therefore two reasons; namely, the absence of marine formation of the oolitic age, and the possible descent of some of the animals and plants from those that lived at that period; for supposing that after the deposition of the palæozoic rocks, what is now Australia was raised into dry land, and that some portion or portions of it at all