The Plane trees, the Sassafras, the curious Ginkgo tree or fern-leaved yew of Japan, are cases of similar decadence of genera once represented by many species, while other trees, like the Willows and Poplars, the Maples, the Birches, the Oaks and the Pines, though of old date, are still as abundant as they ever were, and some genera would seem even to have increased in number of species, though on the whole the flora of our modern woods is much less rich than those of the Miocene and Eocene, or even than that of the Later Cretaceous. The early Tertiary periods were, as we know, times of exuberant and gigantic animal life on the land, and it is in connection with this that the vegetable world seems to have attained its greatest variety and luxuriance. Even that early post-glacial age in which primitive man seems first to have spread himself over our continents was one richer both in animal and plant life than the present. The geographical changes which closed this period and inaugurated the modern era seem to have reduced not only the area of the continents but the variety of land life in a very remarkable manner. Thus our last lesson from the genesis and migrations of plants is the humbling one that the present world is by no means the best possible in so far as richness of vegetable and animal life is concerned. Reference has been made to the utility of fossil plants as evidence of climate; but the subject deserves more detailed notice. I have often pondered on the nature of the climate evidenced by the floras of the Devonian and Carboniferous; but the problem is a difficult one, not only because of the peculiar character of the plants themselves, so unlike those of our time, but because of the probably different meteorological conditions of the period. It is easy to see that a flora of tree-ferns, great lycopods and pines is more akin to that of oceanic islands in warm latitudes than anything else that we know. But the Devonian and Carboniferous plants did not flourish in oceanic islands, but for the most part on continental areas of considerable dimensions, though probably more flat and less elevated than those of the present day. They also grew, from Arctic latitudes, almost, if not altogether, to the equator; and though there are generic differences in the plants of these periods in the southern hemisphere, yet these do not affect the general facies. There are, for example, characteristic Lepidodendroids in the Devonian and Carboniferous of Brazil, Australia, and South Africa. If now we consider the plants a little more in detail, coniferous and taxine trees grow now in very different latitudes and climates. There is therefore nothing so very remarkable in their occurrence. The great group of Cordaites may have been equally hardy; but it is noteworthy that their geographical distribution is more limited. In Europe, for example, they are more characteristic in France than in Great Britain. Ferns and Lycopods and