INTERGLACIAL EPOCHS. 317 



There are certain other Italian freshwater deposits which 

 have yielded many mammalian remains belonging to the same 

 fauna as that of Leffe and Borlezza. I refer to the freshwater 

 beds of the Upper Val d'Arno between Florence and Arezzo. 

 There are two series of deposits in that region, the lower of which 

 is composed of blue clays, whitish sandy marls, and yellow 

 sands, more or less argillaceous and ferruginous. These beds 

 have yielded remains of Mastodon longirostris and M. arvcmensis, 

 together with plants and certain freshwater-shells, belonging to 

 characteristic Pliocene types, and are therefore older than any 

 of the glacial and interglacial deposits we have been studying. 

 Above them, however, comes a group of beds of which the most 

 characteristic is a conglomerate locally known as "Sansino," 

 formed of nodules of clay, and other small concretionary masses, 

 commingled with little angular fragments of various kinds of 

 rock, and bits of mammalian bones. A bed of this " Sansino " 

 forms the base of the upper group. 1 Above it comes a thick 

 series of sands, gravels, and various-coloured clays in alternate 

 layers, which are characterised by abundant remains of the 

 Pleistocene mammalia — amongst which are fflephas meridionalis, 

 Rhinoceros leptorhinus, Hippopotamus major, Ursus etmscus, 

 Equus Stenoni, Bos etruscus, and several deer, such as Cervus 



zerland have dug a course for themselves through the interglacial and glacial 

 deposits of earlier times. Now the Ceppo is of precisely the same character as the 

 so-called " alpine diluvium," and would thus appear to have had a similar origin. 

 It would in this view represent the flood-gravels of an early glacial epoch — the 

 frontal moraines of which have long since been demolished by the action of the 

 Po and its numerous tributaries, just as those of the ancient Rhone glacier have 

 to a large extent vanished from the plains of France. It is quite possible, indeed, 

 that many of the erratics which are scattered over the hills of Turin may have 

 been carried thither by glaciers during the climax of glacial cold. This possi- 

 bility occurred to me when I first visited that district some years ago, and subse- 

 quent explorations have tended to confirm my suspicion that the erratics of the 

 Superga have not all been derived from the destruction of the great Miocene 

 conglomerate-beds. When I first made this suggestion (1871), I was not aware 

 that I had been anticipated by Dr. Julien. — See Des Phenomenes Glaciaires dans 

 le Plateau Central de la France (1869), p. 50. 



1 Professor Mayer insists upon the existence of a clear line of demarcation 

 between the Pliocene and Pleistocene deposits of the Val d'Arno. See Bull. Soc. 

 G60I. France, 3 e Ser. t. iv. p. 208 et seq. 



