Page:Great Neapolitan Earthquake of 1857.djvu/360

288 had been thrown towards the west, and from the position of the fallen material, the direction of the wave-path proved to have been N. 140° W. The portion of the road to the west of the fissure, had slipped and descended about 4 to 6 inches below the former level, as shown in section $$b$$. It was impossible to tell, whether the revetment wall had been founded upon the rock or not, but from the appearance of the ground at its base to the westward, I believed it had not: in any case, it had gone out at the base, towards the west, and with the mass of earth behind, had been severed from the remainder of the road filling, and slipped at the same moment. It is a case very analogous to the Auletta fissures, with this difference, that here, from the unsupported position of the road embankment and revetment, and the direction of the shock, the separation had much more nearly approached a "throw off" at the instant of shock, mixed with the movement of slip or descent.

About a mile further on, just before the rapid descent commences into the Valley of Diano, another set of road fissures had been formed, where the road is also in side cutting, but slopes off at the western side without any revetment. Here the fissures which are shown in Photog. No. 158 are clearly produced by the slippage off to the westward, of an enormous breadth of the clay land, reposing upon a surface of limestone—sloping westward at about 20° to the horizon—and with beds not much more inclined, and dipping in the same direction, circumstances all favourable to a large slip. The direction of wave-path shown, is about the same as the preceding. The telegraph poles all along this portion of the road, I remarked, had been loosened in the ground, and thrown out of plumb,