"A difference not less important distinguishes this Flora from that of the most ancient epochs; namely, the absence, in all these formations, of the family of Ferns, which, on the contrary, furnishes so prominent a feature in the Miocene epoch. No trace of them occur in Europe in the Pliocene formations I have enumerated; while the woods of this family are very abundant in the formations of the West Indies, which is considered as an epoch at least as recent as the Pliocene formation, which appears to indicate that at this period the zones of vegetation were distributed nearly as at present.
"Indeed, in these modern formations of the Antilles, we find among the fossil woods, the only portions of their vegetables that have hitherto been collected, specimens which indicate the existence, not only of numerous and varied palms, but of many other families of the equatorial zone, such as Lianes, nearly related to Bauhinia and Menispermeæ, Pisonia, &c. The vegetation of the Antilles had therefore at this period the characters of the equatorial zone, as in Europe it had then the characters of the temperate zone.
"Lastly, and to terminate our observations on this Flora of the latter geological epoch which preceded the present one, we would remark that, notwithstanding the general analogies which exist between the vegetables of these formations and those now living in the temperate regions, no species appears to be identical, at least with the plants that still grow in Europe; and if, in some rare cases, complete identity appears to exist, it is between these vegetables and American species. Thus the Flora of Europe, even at the most recent geological epoch, was very different from the European Flora of the present day."--_L'Institut._
_Glacial Theory of the Erratics and Drift of the New and Old Worlds_.[45] By Professor L. AGASSIZ.
Footnote 45: _Vide_ Lake Superior, its physical character, vegetation, and animals. By Professor Louis Agassiz. 1850.
_Glacialists and Antiglacialists.--Erratic basins of Switzerland.--Similar phenomena observed in other parts of Europe.--Points necessary to be settled; first, the relation in time and character between the Northern and the Alpine erratics.--Traced in North America.--Not yet settled whether any local centres of distribution in America; but the general cause must have acted in all parts simultaneously.--This action ceased at 35° north latitude; this incompatible with the notion of currents.--In both hemispheres a direct reference to the Polar Regions.--Difficulty_ _as to so extensive formation of Ice, removed; difficulties on the theory of Currents, the effects contrary to experience of Water-Action.--Erratic phenomena of Lake Superior.--The Iceberg theory.--Description of appearances at Lake Superior.--Drift; contains mud, and is without fossils.--Example of juxtaposition of stratified and unstratified Drift, at Cambridge.--Date of these phenomena not fully determined, but doubtless simultaneous all over the Globe.--The various periods and kinds of Drift distinguished.--Accompanied by change of level in the Continent._