BELONGING TO THE STONE AND BRONZE AGE. 139 



The more complete destruction of the piles belonging to 

 the earlier period depends not only on their greater age, but 

 on their occurrence in shallower water. The action of the 

 waves being greatest near the surface, and diminishing gra- 

 dually downwards, not only are those piles which occupy the 

 deeper parts, least liable to destruction, but in each the 

 erosion takes place gradually from above, so that the 

 upper end of the piles is often more regularly pointed 

 even than the lower. Lying among them are fragments 

 of bone, horn, pottery, and sometimes objects of bronze. 

 Most of these are imbedded in the mud or hidden under 

 the stones, but others lie on the bottom yet uninjured ; 

 so that when for the first time I saw them through the 

 transparent water, a momentary feeling of doubt as to their 

 age rose in my mind. So fresh and so unaltered, they look 

 as if they were only things of yesterday, and it seems hard to 

 believe that they can have remained there for centuries. The 

 explanation of the difficulty is, however, to be found in the 

 fact that the action of the most violent storms is perceptible 

 only to a small depth. Except, therefore, near the mouths 

 of rivers, or where there is much vegetation, the deposition 

 of mud at depths greater than four feet is an extremely slow 

 process, and objects which fall to the bottom in such situa- 

 tions will neither be covered over nor carried away. " J'ai 

 peche," says M. Troyon, "sur 1' emplacement en face du Mou- 

 lin de Bevaix, les fragments d'un grand vase qui gisaient a 

 peu de distance les uns des autres, et que j'ai pu reunir de 

 maniere a les remontre completement. A la Tongue, pres 

 d'Hermance, j'ai trouve les deux fragments d'un anneau sup- 

 port, distants de quelques pieds, qui, en les rapprochant ne 

 laissent aucun interstice." The upper parts of the objects 

 also, which are bathed by the water, are generally covered by 

 a layer of carbonate of lime, while the lower part which has 

 sunk into the mud is quite unaltered. M. Troyon once 



