"M. Kurr has likewise described and figured, under the name of Chondrites bollensis, a fucus of the Lias—the very varied forms of which are almost identical with the Chondrites targionii, æqualis, and difformis.

"VI. Tertiary Period.—Considered as a whole, the vegetables of this period, cotemporary with all the Tertiary deposits, and continued even in the vegetation which now covers the earth's surface, is one of the best characterised. The abundance of Angiospermous dicotyledons, that of the monocotyledons of diverse families, but especially the Palms, during a part at least of this period, immediately distinguish it from the most ancient periods. Yet the observations made on the Cretaceous epoch have established a kind of transition between the forms of the Secondary epochs and those of the Tertiary epochs, which was not suspected a few years ago. But while, at this period, the Angiosperms appear nearly to equal the Gymnosperms, in the Tertiary period, they greatly exceed them; while at the Cretaceous epoch, there are still Cycadeæ and Coniferæ allied to the genera inhabiting tropical regions; during the Tertiary period, the Cycadeæ appear to have been completely wanting in Europe, and the Coniferæ belong to the genera of the temperate regions.

"Notwithstanding this assemblage of characters common to the whole Tertiary period, there are evidently notable differences in the generic and specific forms, and in the predominance of certain families at different epochs of this long period; but here we often experience serious difficulties in establishing a uniformity as to time among the numerous local formations which constitute the different Tertiary formations. In assigning the different localities where fossil vegetables have been observed to the principal divisions of the Tertiary series, I have not followed exactly the bases admitted by M. Unger in his Synopsis; I have approached nearer to the distribution adopted by M. Raulin, in his Memoir on the Transformations of the Flora of Central Europe during the Tertiary period (Ann. Sc. Nat., t. x., p. 193, Oct. 1848), which refers many of the formations, classified by M. Unger in the Miocene division, to the Pliocene, or most recent epoch. Yet, according to the advice of M. Elie de Beaumont, I have not placed all the Lignite formations of Germany in the Pliocene division, as M. Raulin has done, nor all of them in the Miocene division, like M. Unger; but, conformably to the old opinion of my father, I have left the Lignites from the shores of the Baltic, which include amber, in the inferior division of the old basins of Paris, London, and Brussels, considering them cotemporary with the Soisson Lignites. Those of the banks of the Rhine, of Wetteravia and Westphalia, are arranged in the Miocene division; those of Styria, and part of Bohemia, on the contrary, are placed among the recent or Pliocene formations.

"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 Œningen 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
Epoch.		Miocene
Epoch.		Pliocene
Epoch.
Cryptogams,33...10...13...
Amphigenous,...16...6...6
Acrogenous,...17...4...7
Phanerogams,..................
Monocotyledons,3333262644
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, 1st, In the Eocene period, the presence, but rarity, of the palms, limited to a small number of species.