28 DATE OF BRONZE AND STONE PERIODS. CHAP. ii. 



very gradually, and by the uniform action of the same causes. 

 Three layers of vegetable soil, each of which must at one time 

 have formed the surface of the cone, have been cut through 

 at different depths. The first of these was traced over a 

 surface of 15,000 square feet, having an average thickness of 

 five inches, and being about four feet below the present siu'face 

 of the cone. This upper layer belonged to the Eoman period, 

 and contained Eoman tiles and a coin. The second layer, 

 followed over a surface of 25,000 square feet, was six inches 

 thick, and lay at a dej)th of ten feet. In it were found 

 fragments of unvarnished pottery and a pair of tweezers in 

 bronze, indicating the bronze epoch. The third layer, fol- 

 lowed for 35,000 square feet, was six or seven inches thick, 

 and nineteen feet deep. In it were fragments of rude pottery, 

 pieces of charcoal, broken bones, and a human skeleton having 

 a small, round, and ver}' thick skull. M. Morlot, assuming 

 the Roman period to represent an antiquity of from sixteen 

 to eighteen centuries, assigns to the bronze age a date of 

 between 3000 and 4000 years, and to the oldest layer, that of 

 the stone period, an age of from 5000 to 7000 years. 



Another calculation has been made by M. Troyon to obtain 

 the approximate date of the remains of an ancient settle- 

 ment built on piles and preserved in a peat-bog at Chamblon, 

 near Yverdun, on the Lake of Neufchatel. The site of the 

 ancient Eoman town of Eburodunum (Yverdon), once on the 

 borders of the lake, and between which and the shore there 

 now intervenes a zone of newly-gained dry land, 2500 feet in 

 breadth, shows the rate at which the bed of the lake has been 

 filled up with river sediment in fifteen centuries. Assuming 

 the lake to have retreated at the same rate before the Eoman 

 period, the pile-works of Chamblon, which are of the bronze 

 period, must be at the least 3300 years old. 



For the third calculation, communicated to me by M. 

 Morlot, we are indebted to M. Victor Gillioron, of Neuve- 



