Another Austrian naturalist, the well-known botanist Professor Unger of Vienna, has come to the same conclusions from the fossil remains of some Australian plants, accompanied by the further singular deduction, that Europe must have been at one period in much closer accordance with this remote region. Many forms of plants, especially _Proteaceæ_, which at present form such a peculiar feature of its vegetation, seem to have been similarly prevalent in Europe at that remote age of the globe. But if even it be accepted that during the Eocene or earliest tertiary period there existed in Europe under similar climatic conditions flora of _Coniferæ_, _Proteaceæ_, _Myrtaceæ_, and _Casurinæ_, such as Australia now possesses, the question still arises as to how the vegetation of a locality so remote should have been transferred to antipodean Europe? Making all due allowance for the astonishing influence exercised by winds, waves, and the migration of animals over the diffusion of vegetable species, yet the means of transport by the ocean or by currents of water is confined within narrow limits, and under the most favourable conditions is limited to the very few plants which can maintain their powers of reproduction uninjured by immersion in water, and those on the other hand which, on being transported to a strange shore, find there the means of existence and increase. As, moreover, the observations which Professor Unger has made upon the diffusion of species of plants at that remote period, and their very accurately circumscribed limits, run directly counter to the opinion of those naturalists who hold to a variety of centres of development, (instancing a case where one species of plants is found in two widely separated regions,) have never been satisfactorily refuted, the learned botanist thereupon proceeds to the conclusion, that during the Eocene period Australia was united to the mainland through the Moluccas. This land route has been followed at one period by _Araucarias_, _Proteaceæ_, sandal wood, and a hundred other varieties of tree and shrub, which till that connection was made could not diffuse themselves, so as thus to reach the European continent, where they are even now found, despite the lapse of myriads of years, in the shape of well-preserved fossils. Thus too, for similar reasons, the geologist to our Expedition, like Professor Unger, regarded Australia as not a youthful, lately-born continent, but a country decaying with antiquity, which had played its part in the physical history of the globe, and had spread its scions far and wide. Some alteration of level is not merely indicated by the numerous coral reefs encircling Australia and its island groups, pointing to a similar sinking among them as that already noticed among the smaller Polynesian islands:--The whole characteristics of the soil, the wastes of the interior, the innumerable salt lakes, the rivers which lose themselves in these, &c.