Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/190

Rh way, to the left. All these fissured lands, lay to the east of the great valley gorge of the Giacojio and the Platano, &c.; and except the minor torrents, such as the Marmo and others delivering into the Platano, were not cut off by any great and continuous valley courses from the neighbourhood of the focal region of the earthquake, between which and this place many of the prolonged lower ridges assume a direction about north and N.E., or end on to the wave-path.

Moreover, the great mass of Monte Marmo lies nearly (a little east) in the line of the wave-path from the southward. All these circumstances conspired to make the shock considerably more severe about the Isca di Bella, than at Bella town, and at Muro, which, although so near, lie at the west side of the great chasm.

A very small amount of shaking, however, upon this unctuous and treacherous soil, might set in movement the most enormous slippages; so that there is little necessary connection between the extent of the landslip, and that of the shock originating it; in fact, the common phenomena of slippage in heavy railway embankments, which are generally brought to the final point of moving by the vibration of a passing train, is a case in point; indicating how little the violence of the shock can be judged of by the extent of such landslips. There was nothing, except the large scale of the occurrence remarkable, beyond what I had already carefully examined at Campostrina, at Auletta, in the valley of Viggiano, where the dislodgment was quite as striking, and elsewhere.

Judging from the character of the wild region, that for many square miles seems to consist of these clay

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