148 



THE GEOLOGIST. 



stratum of 'black aslies ' of tlie Laonnois, at a depth so considerable tinder 

 the soil and under conditions of bedding such that it is impossible to com- 

 prehend how and by what means it could have been introduced in recent 

 times. I am certamly 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 con- 

 temporary 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 explana- 

 tion. I content myself with giving it to science, and I shall wait l3efore 

 forming an opinion in this respect, for further discoveries to furnish me 

 with the means of appreciating the value of this at Montaigu."— Melle- 

 viLLE, 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,* 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 Y arese, 

 Nese, San-Colombo, and Casteneddo were deposited. 



With the slow and gradual dislocation by which the Alps and the Apen- 

 nines took their present forms, the valley of the Po became a great shallow 

 gulf, when the most ancient of the quaternary rocks were formed, con- 

 stituting 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 alluviimi," which by de- 

 grees advanced the land and diminished the extent of the gulf. The stones 

 brought b}" the glaciers lose their polish, their groovings and striae 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, 



Tlie glaciers now extend still further, denuding the upper part of the 

 anuvium and leaving on its lower part their terminal moraines, where we 

 still find them. The production of alluvium still went on extending the 

 land. Tins 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 conconlric moraines nearer the high Alps. The torrents 

 wear away the nioraines which they encounter and transport the material 

 to various distances, forming the most superficial portion, called "recent 



* .Vlli (l(.lla Soc. Nat. in Milano, 1861, t. iii., with a map of the ancient extension of 

 tlic glaciers. 



