Bronze epoch. The third layer has been followed for 3500 square feet; it was six or seven inches in thickness, and lay at a depth of 19 feet (5.69 metres) below the present surface: in it were found some fragments of very rude pottery, some pieces of charcoal, some broken bones, and a human skeleton with a small, round, and very thick skull. Fragments of charcoal were even found a foot deeper, and it is also worthy of notice that no trace of tiles was found below the upper layer of earth.
Towards the centre of the cone, the three layers disappear, since, at this part, the torrent has most force, and has deposited the coarsest materials, even some blocks as much as three feet in diameter. The farther we go from this central region the smaller are the materials deposited, and the more easily might a layer of earth, formed since the last great inundations, be covered over by fresh deposits. Thus, at a depth of ten feet, in the gravel on the south of the cone, at a part where the layer of earth belonging to the bronze age had already disappeared, two unrolled bronze implements were discovered. They had probably been retained by their weight, when the earth, which once covered them, was washed away by the torrent. After disappearing towards the centre of the cone, the three lavers reappear on the north side, at slightly greater depth, but with the same regularity and the same relative position. The layer of the Stone age was but slightly interrupted, while that of the Bronze era was easily distinguishable by its peculiar character and colour.
Here, therefore, we have phenomena so regular, and so well marked that we may apply to them a calculation, with some little confidence of at least approximate accuracy. Making then some allowances, for instance, admitting three hundred years instead of one hundred and fifty, for the period since the embankment, and taking the Roman period as representing an antiquity of from sixteen to eighteen centuries, we should have for the age of Bronze an antiquity of from 2900 to 4200 years, for that of the Stone period from 4700 to 7000 years, and for the whole cone an age of from 7400 to 11,000 years. M. Morlot thinks that we should be most nearly correct in deducting two hundred years only for the action of the dykes, and in attributing to the Roman layer an antiquity of sixteen centuries, that is to say, in referring it to the middle of the third century. This would give an age of 3800 years for the Bronze age and 6400 years for that of Stone, but on the whole he is inclined to suppose for the former an antiquity of from 3000 to 4000 years, and for the latter of from 5000 to 7000 years.
In the settlement at the foot of Mt. Chamblon we have, according to M. Troyon, a second instance in which we obtain at least some approximation to a date. The interest which attaches to this case arises from the fact that Pileworks have been found in the peat at a considerable distance from the lake, whereas it is evident that at the time of their construction the spot in which they occur must have been under water, as this mode of building would have been quite
