350 LECTURE XII. 



These facts enable us to form some definite deduction regard- 

 ing the age of the pile-works. The alluvial formation in which^ 

 in certain Swiss districts, are found the remains of the ele- 

 phant and the rhinoceros, lies beneath the white bottom into 

 which the piles are driven. It follows, therefore, that the 

 white bottom must have attained a thickness of several feet 

 before the pile-works were erected, inasmuch as the piles are 

 only driven into this layer and not into the gravel. But for 

 the formation of such a lake-bed, consisting of an enormous 

 mass of shells, many centuries were requisite, for we know that 

 though mussels and snails frequently abound in freshwater, still 

 many years are required for the formation even of a thin bed. 

 Thus the settlements in Switzerland are much more recent 

 than the beds of Amiens and the cave beds in which human 

 remains have been found. Nevertheless, they reach back to a 

 remote period, which has no history, the age of which may 

 perhaps be approximatively estimated by the growth of the peat 

 which has overgrown these pile-works. Hitherto we possessed 

 no correct standard for the growth of peat. The calculations 

 hitherto made rest upon no certain foundations, as the up- 

 heaving of the peat soil has been erroneously taken for its 

 growth. 



The great number of pile-works successively discovered in 

 Switzerland, though they possess many features in common, 

 differ specifically with respect to the metals and other imple- 

 ments found in some of these pile-works. It is undeniable 

 that in East- Switzerland there are numerous pile-works in 

 which none, or but few, metals are found, whilst on the con- 

 trary, in Vf est- Switzerland there are many such works wliich 

 contain objects of the bronze or both periods, whilst in some 

 have been found iron tools, and even Roman coins. To draw, 

 as Troyon has done, a geographical line, is inadmissible, and 

 some settlements afford clear indications that they have been 

 inhabited during the whole period and successively enlarged. 

 Notwithstanding this, we are able to distinguish the stone- from 

 bronze-period buildings, first by their depth, and secondly by 

 the modes in which the piles are worked, independently of the 

 objects found in them. The piles of the stone-period are much 



