Taurentum, another Roman town, situated, it is said, on the banks of Lake Geneva, at the base of one of the spurs of the Dent d'Oche, was completely crushed in A. D. 563 by a downfall of rocks. The sloping heap of débris thus formed may still be seen advancing like a headland into the waters of the lake. A terrible flood-wave, produced by the deluge of stones, reached the opposite shores of the lake and swept away all the inhabitants. Every town and village on the banks, from Morges to Vevay, was demolished, and they did not begin the work of rebuilding till the following century. Some say, however, that the disaster was caused by a landslip which fell from the Grammont or Derochiaz across the valley of the Rhone, just above the spot where it flows into the Lake of Geneva. Hundreds of such falls have taken place within the Alps and neighbouring mountains within historic times.
Two out of the five peaks of the Diablerets fell down, one in 1714 and the other in 1749, covering the pastures with a thick layer of stones and earth more than three hundred feet thick, and by obstructing the course of the stream of Lizerne, formed the three lakes of Derborence. In like manner the Bernina, the Dent du Midi, the Dent de Mayen, and the Righi have overspread with ruin vast tracts of cultivated land. In Switzerland the most noted Bergfalls are those from the Diablerets and the Rossberg. The former mountain is a long flattish ridge with several small peaks, overhanging very steep walls of rock on either side. These walls are composed of alternating beds of limestone and shale. Hence it is easily perceived that we have here conditions favourable for landslips, because if anything weakens one of these beds of shale the overlying mass might be inclined to break away. The fall in the year 1714, already referred to, was a very destructive one.
THE MATTERHORN. From a Photograph by Mr. Donkin.
"For two whole days previously loud groaning had been heard to issue from the mountain, as though some imprisoned spirit were struggling to release himself, like Typhœus from under Etna; then a vast fragment of the upper part of the mountain broke suddenly away and thundered down the precipices into the valley beneath. In a few minutes fifty-five châlets, with sixteen men and many head of cattle, were buried for ever under the ruins. One remarkable escape has indeed been recorded, perhaps the most marvellous ever known. A solitary herdsman from the village of Avent occupied one of the châlets which were buried under the fallen mass. Not a trace of it remained; his friends in the valley below returned from their unsuccessful search, and mourned him as dead. He was, however, still among the living; a huge rock had fallen in such a manner as to protect the roof of his châlet, which, as is often the case, rested against a cliff. Above this, stones and earth had accumulated, and the man was buried alive. Death would soon have released him from his imprisonment, had not a little rill of water forced its way through the débris and trickled into the châlet. Supported by this and by his store of cheese, he lived three months, labouring all the while incessantly to escape. Shortly before Christmas he succeeded, after almost incredible toil, in once more looking on the light of day, which his dazzled eyes, so long accustomed to the murky darkness below, for a while could scarcely support. He hastened down to his home in Avent, and knocked at his own door; pale and haggard, he scarcely seemed a being of this world. His relations would not believe that one so long lost could yet be alive, and the door was shut in his face. He turned to a friend's house; no better welcome awaited him. Terror seized upon the village; the priest was summoned to exorcise the supposed demon; and it was not till he came that the unfortunate man could persuade them that he was no spectre, but flesh and blood."[14]
The valley is still a wild scene of desolation, owing to the enormous masses of stones of every shape and size with which its bed is filled.
In September of the year 1806, the second fall of the mountain Rossberg took place, after a wet summer. It is underlaid by beds of clay which, when water penetrates, are apt to give way. The part which fell was about three miles long and 350 yards wide and 33 yards thick. In five minutes one of the most fertile valleys in Switzerland was changed to a stony desert. Three whole villages, six churches, 120 houses, 200 stables or châlets, 225 head of cattle, and much land were buried under the ruins of the Rossberg; 484 persons lost their lives. Some remarkable escapes are recorded.
In the year 1618 the downfall of Monte Conto buried 2,400 inhabitants of the village of Pleurs, near Chiavenna. Excavation among the ruins was subsequently attempted, but a few mangled corpses and a church-bell were all that could be reached.
Geologically these phenomena, appalling as they are from the human point of view, possess a certain interest, and their effects deserve to be studied.