Page:Great Neapolitan Earthquake of 1857.djvu/281

Rh containing very large plates of calc spar. All this, with the scattered patches of tufa, on the south side of the peninsula, where they never could have come sub dio from Vesuvius, indicate that submarine volcanic action, was going on in these regions, before the bay of Naples was separated from that of Salerno at all, by the elevation of the great limestone ridge now between them.

At Vietri, which I visited in a violent storm of rain and wind, I could find no evidences of wave direction worthy of notice. At La Cava, the first very obvious trace of the earthquake challenged notice, in a long range of diagonal timber braces, sustaining the S.W. side of a range of house fronts, which had been thrown so as to lean outwards, bringing with them, the square piers of the old Roman-looking arcades, over which the houses are built (Fig. 119). In the latter were measurable fissures, though small; in the Casa Communale, and in the side and back walls, of some of the strange shadowy open fronted shops, that seem so identical with those of Pompeii, were a few others. From the whole I obtained three indications of wave-path- 15.30 E. of N.; S. to N.; 17 W. of N.—and also some indications of an orthogonal shock, W. to E. At the Benedictine monastery of La Trinita, a few miles from La Cava, I expected to have found much evidence of injury. It lies, in the gorge of a deep and sinuous mountain valley, of metamorphic limestone, hard and shattery, but with much diluvial covering in many places.

The buildings, sound and well constructed, of rubble ashlar chiefly, have generally escaped. There are, however, in two different places in its southern corridors, and near the great south corridor window,