These have all been obtained from caves and late Tertiary or Post-Tertiary deposits, and consist of a large number of extinct forms, some of gigantic size, but all marsupials and allied to the existing fauna. There are numerous forms of kangaroos, some larger than any living species; and among these are two genera, _Protemnodon_ and _Sthenurus_, which Professor Garrod has lately shown to have been allied, not to any Australian forms, but to the _Dendrolagi_ or tree-kangaroos of New Guinea. We have also remains of _Thylacinus_ and _Dasyurus_, which now only exist in Tasmania; and extinct species of _Hypsiprymnus_ and _Phascolomys_, the latter as large as a tapir. Among the more remarkable extinct genera are _Diprotodon_, a huge thick-limbed animal allied to the kangaroos, but nearly as large as an elephant; _Nototherium_, having characters of _Macropus_ and _Phascolarctos_ combined, and as large as a rhinoceros; and _Thylacoleo_, a phalanger-like marsupial nearly as large as a lion, and supposed by Professor Owen to have been of carnivorous habits, though this opinion is not held by other naturalists. Here then we find the same phenomena as in the other countries we have already discussed,--the very recent disappearance of a large number of peculiar forms, many of them far surpassing in size any that continue to exist. It hardly seems probable that in this case their disappearance can have been due to the direct effects of the Glacial epoch, since no very extensive {158}glaciation could have occurred in a country like Australia; but if the ocean sank 2,000 feet, the great eastern mountain range might have given rise to local glaciers. It is, however, almost certain that during late Tertiary times Australia must have been much more extensive than it is now. This is necessary to allow of the development of its peculiar and extensive fauna, especially as we see that that fauna comprised animals rivalling in bulk those of the great continents. It is further indicated by the relations with New Guinea, already alluded to, and by the general character of the various faunas which compose the Australian region, details of which will be found in the succeeding part of this work. The lowering of the ocean during the Glacial period would be favourable to the still further development of the fauna of such a country; and it is to the unfavourable conditions produced by its subsequent rising--equivalent to a depression of the land to the amount of two thousand feet--that we must impute the extinction of so many remarkable groups of animals. It is not improbable, that the disappearance of the ice and the consequent (apparent) subsidence of the land, might have been rapid as compared with the rate at which large animals can become modified to meet new conditions. Extensive tracts of fertile land might have been submerged, and the consequent crowding of large numbers of species and individuals on limited