v.] PREHISTORIC ARCHEOLOGY. 157 



lithic Age, we conclude that these shell-mounds do not 

 belong to that period, so, on the other hand, from the 

 absence of all trace of metal, we are justified in referring 

 them to a period when metal was unknown. 



6. The same arguments apply to some of the Swiss 

 lake-dwellings, the discovery of which we owe to Dr. 

 Keller, 1 and which have been so admirably studied by 

 Desor, Morlot, Troyon, and other Swiss archaeologists. 

 A glance at the Table A will show that, while in some 

 of them objects of metal are very abundant, in others, 

 which have been not less carefully or thoughtfully 

 explored, stone implements are met with to the exclu- 

 sion of metallic ones. It may occur, perhaps, to some, 

 that the absence of metal in some of the lake-villages, 

 and its presence in others, is to be accounted for by its 

 scarcity that, in fact, metal will be found when the 

 localities shall have been sufficiently searched. But a 

 glance at the table will show that the settlements in 

 which metal occurs are deficient in stone implements. 

 Take the same number of objects from Wangen and 

 Nidau, and in the one case 90 per cent, will be of metal, 

 while in the other the whole number are of stone or 

 bone. This cannot be accidental the numbers are too 

 great to admit of such a hypothesis ; nor can the fact be 

 accounted for by contemporaneous differences of civili- 

 zation, because the localities are too close together; 

 neither is it an affair of wealth, because we find such 

 articles as fishhooks, &c., made of metal. 



7. We may also, I think, safely refer some of the 

 tumuli or burial mounds to this period. When we find 



1 Dr. Keller's Memoirs have been collected and translated into 

 English by Mr. Lee. 



