164 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 



