stratum of 'black ashes' of the Laonnois, at a depth so considerable under the soil and under conditions of bedding such that it is impossible to comprehend how and by what means it could have been introduced in recent times. I am certainly amongst those who think that science has not yet said its last word about it. But from one fact, even so well established, I do not pretend to draw the extreme conclusion that man was contemporary with the lignites of the Paris basin. . . . My sole object in writing this notice is to make known a discovery as curious as strange, whatever may be its bearing, without pretending to any mode of explanation. I content myself with giving it to science, and I shall wait before forming an opinion in this respect, for further discoveries to furnish me with the means of appreciating the value of this at Montaigu."—Melleville, Vice-President of the Academic Society of Lahon.
Such is M. Melleville's account, and we consider his resolution wise in hesitating to date back the age of man to the lower tertiary period of the Paris basin without further confirmatory evidence.
M. Omboni, in his paper on the Ancient Glaciers and "terrain erratique" of Lombardy, lately published by the Milan Society,[1] has given numerous details of the different valleys which debouche in Lombardy between the Lake of Orta and Brescia and of the glacial deposits they contain. All these have been visited by him, and he has particularly examined with great care the traces left by the glaciers of their lower limits. He indicates clearly where the enormous masses of ice, after having been long encased in the valleys of the southern flanks of the Alps, spread out and melted in the plain, leaving in front of them their terminal moraines. His principal conclusions are, that, during the Pliocene age, the valley of the Po formed part of the Pliocene Sea when the marine fossiliferous rocks of Varese, Nese, San-Colombo, and Casteneddo were deposited.
With the slow and gradual dislocation by which the Alps and the Apennines took their present forms, the valley of the Po became a great shallow gulf, when the most ancient of the quaternary rocks were formed, constituting the passage-beds from the Pliocene, and enclosing the bones of large quadrupeds. Then followed the commencement of the formation and the extension of the glaciers of the Alps in consequence of a cold and damp climate. This was the first part of the quaternary glacial epoch.
Next, the glaciers occupied all the valleys of the Alps and the basins of the lakes as far as the points where they now are, Sesto-Calende, Porto, Mendrisio, Como, Lecco, Iseo, etc. Great torrents dispersed the materials brought by the glaciers and formed the "ancient alluvium," which by degrees advanced the land and diminished the extent of the gulf. The stones brought by the glaciers lose their polish, their groovings and striæ become rounded and form part of the alluvium, while the large blocks are also rounded by the action of water. This was the second part of the glacial epoch.
The glaciers now extend still further, denuding the upper part of the alluvium and leaving on its lower part their terminal moraines, where we still find them. The production of alluvium still went on extending the land. This was the third part of the glacial epoch.
Then a change takes place—the climate becomes less cold. The glaciers diminish and slowly arrive at their present limits, and during this period of retreat form concentric moraines nearer the high Alps. The torrents wear away the moraines which they encounter and transport the material to various distances, forming the most superficial portion, called "recent
- ↑ Atti della Soc. Nat. in Milano, 1861, t. iii., with a map of llie ancient extension of the glaciers.
