The new Cretaceous flora appears first in beds which had been recently elevated from the ocean of the great Cretaceous subsidence; and when it first flourished, in temperate regions at least, the continents were of small dimensions, and broken up into groups of islands. Farther, America would seem to have had precedence of the Eastern Continent, and the Arctic of the Temperate regions. Thus on the elevation of the later Cretaceous land, plants previously established in the far north spread themselves southward, over newly-raised lands, radiating from the polar regions into Europe, Asia, and America. This seems the only way of accounting for the similarity of the plants in these distant countries. The new flora of the Upper Cretaceous in its journey southward met with a climate probably warmer than the present, yet not so warm as to prevent trees similar to those now living in the same latitudes from flourishing. Let us now trace this flora through the succeeding ages, in which I shall follow pretty closely some general statements made by Count De Saporta in memoirs recently published. [Illustration: FIG. 159.—Eocene Leaves. From Aix. _a_, _Quercus antecedens_ (Saporta). _b_, _Diospyros pyrifolia_ (Saporta). _c_, _Myrica Mathesonii_ (Saporta).] At the beginning of the Eocene we find a humid and warm climate in Europe, with great forests of oaks, chestnuts, laurels, giant pines, and other genera, some of them still European, others Asiatic or American, and many of them survivors of the Cretaceous (Figs. 159 to 162); and at the same period similar forests overspread those great plains of North America which were rising from out the Cretaceous sea, and there vast swampy beds were formed of vegetable _débris_, giving origin to beds of brown coal, some of them eighteen feet in thickness. Then came in Europe and Asia that great subsidence under the sea, during which the Nummuline limestones were deposited, and when the old continent was resolved again into an archipelago of islands, perhaps closely connected with more southern lands. This led to a great increase of southern forms of plants, which does not seem to have occurred to the same extent in America, where the flora is more continuous, though showing a warmer climate in the older than in the newer Eocene. At this period Palms, Screw pines, Proteaceous shrubs, Myrtles, _Acacias_, and other plants of the character of those of more southern climates were dominant in Europe (Fig. 163). The well-known beds of Bournemouth, in the south of England,[74] contain a rich flora of the Eocene age, perhaps of its middle period, and reminding us of the forests of sub-tropical India or Australia. [Illustration: FIG. 160.—An Ancient Clover (_Trifolium palæogæum_, Saporta). Eocene. Aix.] [Illustration: FIG. 161.—An Eocene Maple (_Acer sextianus_, Saporta). Aix.] [Illustration: FIG. 162.—A European Magnolia of the Eocene (_M. dianæ_, Saporta). Aix.]