In making a section through the La Tène elevation there is first encountered a bed of water-worn gravel and sand, varying in thickness from three or four feet to as many yards. This gravel had evidently been thrown up by the action of the waves, and in it there are no antiquities found, with the exception of occasional fragments of Roman pottery and tiles. Beneath this superficial gravel there lies a blackish bed of peat of considerable thickness, below which is the ancient lake sediment. It is on the surface of this intermediate mossy bed, and sometimes buried in it, that the objects characteristic of La Tène are found. From these stratigraphical glimpses of Natures workings it would appear that during prehistoric times the whole low-lying district from Préfargier to the lake of Bienne was a shallow bay, which became ultimately overgrown with marsh plants and peat to the extent of forming the "Gross Moos." Scattered throughout the deposits of this quiet bay, and especially along the waterway to Bienne, are frequently found antiquities belonging to all the three ages of prehistoric times previous to the occupation of the locality by the Romans, remains of whom are, of course, also met with. Professor Desor, and others who have carefully examined the locality from a geological point of view, account for the subsequent overspreading of La Tène as the combined result of two natural causes, viz. first, the elevation of the level of the lake owing to sedimentary deposits or accidental obstruction in the channels through which the surplus water found its escape; and, second, the gradual removal, by the action of the waves, of a protective barrier in the shape of a projecting moraine of sand and gravel, which stretched outwards from Préfargier in the direction of La Sauge, and sheltered La Tène for many ages from the action of the open lake. But whatever the explanation may be, it is certain that a considerable change has taken place since these sedimentary deposits of fine silt were formed, as at the present time the amount of gravel thrown up on the shore of La Tène is so great as to advance the beach at the annual rate of two or three yards; and this occurs notwithstanding that the level of the water, owing to the operations necessitated by the "Correction des Eaux du Jura," is even lower than it was when the neighbouring lake-dwellings of the Stone and Bronze Ages flourished.