But whatever may be the result of future discoveries as to the relative age of the bone-deposits, or the existence or extinction of any of the colossal species of Moa, or the former extension of the race over countries now submerged, one astounding fact must ever remain unassailable--the vast preponderance of the class Aves or Birds, that prevailed, and which still prevails, in the fauna of New Zealand, to the almost entire exclusion of mammalia and reptiles. Any palæontologist who saw only the collections sent over by my son, must have been astonished at their extent and variety. I may venture to affirm that such an assemblage of the fossil bones of birds was never before seen in Europe: nearly fifteen hundred specimens, collected from various parts of the country, with scarcely any intermixture of the remains of any other class;--it is a phenomenon as startling as the exclusively reptilian character of the fauna of the Wealden epoch. But the fauna of New Zealand, even at the present time, presents a character as ornithic and as anomalous as its ancient one; for while there are upwards of fifty or sixty genera of birds, there is but one indigenous mammalian quadruped known to naturalists--a species of rat! In this respect, therefore, as well as in its flora, in which ferns and other cellulosæ of peculiar types prevail to an extent unknown elsewhere, the country offers a striking example of that now acknowledged fact in natural history--a centre or focus of creation of certain organic types. And this law, with whose operation during the palæozoic and secondary ages modern geological researches have made us familiar, appears to have continued in unabated energy to the present moment. From what has been advanced, it is manifest that the present geographical distribution of special groups of terrestrial animals and plants, displays as many anomalies in the relative predominance of the different classes and orders over certain areas, without relation to climatorial or other obvious physical conditions, as can be traced in the natural records of the earlier ages of the world. The conclusion therefore forces itself upon the mind, that throughout the vast periods of time to which our retrospective knowledge extends, the geological changes of the earth's surface, and the appearance and obliteration of species and genera, have been governed by the same physical and organic laws; and that notwithstanding the variable conditions of the land and the water, indicated by the sedimentary formations, there was at no period a greater discrepancy in the assemblages of certain types of the animal and vegetable kingdoms, than exists at present.