Page:A sketch of the physical structure of Australia.djvu/101

89 is so much lower and less important than the Andes, its effect is not so decided and important; what effect it does exert, however, is precisely of the same kind and in the same direction.

Our second speculation, is on the past geological history of Australia. Many geologists have been struck with the entire absence of all the "secondary" formations in Australia, and with the analogies between the fossil flora and fauna of our European oolitic series, and those now found living in Australia and the Australian seas. We have seen in the preceding pages that we have in Australia a group of very old rocks, now more or less completely metamorphosed, and associated more or less intimately with granitic rocks; on these we have a palæozoic formation very largely developed, but we have at present no knowledge of the exact relation between the palæozoic and the metamorphic series. Above the palæozoic series there is an absolute gap, a total deficiency of all other stratified rocks whatsoever, so far as is at present known, except those belonging to a tertiary formation, which from the very recent aspect of its fossils and their resemblance to existing forms, I believe to be a very modern one. Now as there seems to be no rocks of the age of our great oolitic and cretaceous formations, they must either have been altogether destroyed and denuded which is unlikely, or they can never have been deposited. This circumstance inclines us to believe, that the country may, most probably, have existed