118 
THE GEOLOGIST. 
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 com- 
prehend 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 estabhshed, 
I do not pretend to draw the extreme conclusion that man was con- 
temporary with tJie 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 before 
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 confirmator}^ 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 Yarese, 
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 i\\e 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 
brouglit by the glaciers and formed the " ancient alluvium," which by de- 
grees advanced the land and diminished the extent of the gulf. The stones 
brought by the glaciers lose their polish, their groovings and strise 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 moraiues, where we 
still find them. The production of alluvium still went on extendmg 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. 
