Page:Great Neapolitan Earthquake of 1857 Vol 2.djvu/179

126 No. 336, the former taken, looking down the slope, and hence showing the inclination badly, the latter looking diagonally up towards the S.E., represent the rained walls of the Taberna della Duc di Gravina, which was destroyed by these "illuviones" in 1836. After a long period of drenching rain, the sloping side of the valley upon which it was founded, began to give way and move bodily downwards, towards the stream at the bottom. The large edifice has been thus launched, above 100 perches west of its original site, and as the mass of clay was shoved on, a mighty plastic mass, (a mud glacier,) over an uneven rocky bed, its surface rose and fell irregularly, but with extreme slowness, and the long walls of the building, were riven nearly vertically, presenting still, in some places, evidence upon their surfaces of the shearing and grinding action. The intermediate great fragments of wall, hence are thrown out of plumb, in the planes of the walls, some up, some down the slope; others are out of plumb across the wall faces, and, what appeared most strange, the whole general line of base, originally quite horizontal, was now out of level, and had assumed the general slope of the slipping mass that carried it, the upper being nearly the height of the walls, 16 feet, higher than the other end, the slope of the land surface generally being about 18° or 20°. The whole mass had also obviously sunk and buried itself, about 3 feet below its original foundation level, and the plastic masses around it, have swelled and risen upon it about the upper end, from inequality of resistance.

The sub-soil upon which it stands, is rendered visible by a streamlet close by, and shows itself to be a deep, slippery, blue marly clay, of great depth, and easily dissolved into