1G4 
OLDER PLIOCENE PERIOD. 
[Ch. XII. 
causes which drifted skeletons into lakes, such as that of the 
upper Val d'Arno, may have carried down others into firths or 
bays of the sea. The femur of an elephant has been disinterred 
with oysters attached to it, showing that it remained for some 
time exposed after it was drifted into the sea. 
Strata at the base of the Maritime Alps. — If we pass from 
the Italian peninsula, and, following the borders of the Medi- 
terranean, examine the tertiary strata at the foot of the 
Maritime Alps, we find formations agreeing in zoological 
characters with the Subapennine beds, and presenting many 
points of analogy in their mineral composition. The Alps, it is 
well known, terminate abruptly in the sea, between Genoa and 
Nice, and the steep declivities of that bold coast are continuous 
below the waters, so that a depth of many hundred fathoms is 
often found within stone's-throw of the beach. Exceptions 
occur only where streams and torrents enter the sea, and at 
these points there is always a low level tract, intervening 
between the mouth of the stream and the precipitous escarp- 
ment of the mountains. 
In travelling from France to Genoa, by the new coast-road, 
we are principally conveyed along a ledge excavated out of the 
side of a steep slope or precipice, in the same manner as on 
the roads which traverse the great interior passes of the Alps, 
such as the Simplon and Mont Cenis, the difference being 
that, in this case, the traveller has always the sea below him, 
instead of a river. But we are obliged occasionally to descend 
by a zig-zag course into those low plains before alluded to, 
which, when viewed from above, have the appearance of bays 
deserted by the sea. They are surrounded on three sides by 
rocky eminences, and the fourth is open to the sea. 
These leading features in the physical geography of the 
country are intimately connected with its geological structure. 
The rocks composing the Alpine declivities consist partly of 
primary formations, but more generally of secondary, which 
have undergone immense disturbance ; but when we examine 
the low tracts before-mentioned, we find the surface covered 
