"This distribution agrees pretty generally with the nature of the vegetables contained in them. One important point only leaves me in doubt: this relates to the Lignites of the environs of Frankfort or Wetteravia, the plants of which are pretty generally analogous to those of OEningen or Partschlug in Styria; although their geological position seems to call upon us to refer them to a more ancient formation. "It is probable that a more complete knowledge of these diverse deposits would lead to a division into distinct epochs more numerous; but I think that, in the meantime, the division into three principal epochs, which I shall designate, with the majority of geologists, by the names Eocene, Miocene, and Pliocene, is sufficient for a comparison of the successive changes of the vegetable kingdom. I shall point out for each of them the localities which I think should be comprehended under these different designations. "With regard to the general characters which result from the comparative examinations of these Floras, we find that the number of species, in the great divisions, are thus distributed in these three Floras:-- Eocene Miocene Pliocene Epoch. Epoch. Epoch. -------- -------- -------- Cryptogams, 33 ... 10 ... 13 ... Amphigenous, ... 16 ... 6 ... 6 Acrogenous, ... 17 ... 4 ... 7 Phanerogams, ... ... ... ... ... ... Monocotyledons, 33 33 26 26 4 4 Dicotyledons, 143 ... 97 ... 195 ... Gymnosperms, ... 40 ... 19 ... 31 Angiosperms, ... 103 ... 78 ... 164 --------- -------- -------- Total, 209 ... 209 ... 212 ... "It may only be remarked that, in the first column, or Eocene formation, the fossil fruits of the Isle of Sheppey--a part only of which have been described by M. Bowerbank--have a great influence on the numbers of the different divisions of Phanerogams, and that this locality appears altogether exceptional, and is, perhaps, an example of the effect of currents conveying exotic fruits from remote climates, and accumulating them on a point of the shores of Europe. "In this point of view, the enumeration of the plants of this first epoch is in no way comparable to that of the other epochs, where I have refrained even from introducing the small number of fossil plants from the Tertiary formations of the equatorial regions that are known, in order to confine myself to a comparison of the Tertiary Floras of Europe. "With regard to the characters drawn from vegetable forms during these three epochs, the most remarkable appear to me, 1_st_, In the Eocene period, the presence, but rarity, of the palms, limited to a small number of species.