Page:Great Neapolitan Earthquake of 1857.djvu/239

Rh resemblance to pieces of petrified serpents, have been denominated serpentini. To these kinds of configuration we may add the spheroidical masses with laminated concentric structure, found in the vicinity of Alberona, in Capitanata, and the prismatic forms of the valley of Ansanto, outwardly composed of large crusts of Limonite with Siderosa, and filled interiorly with marl, and often with pieces of the same Limonite. In the sandstone, besides the minute grains and rounded pebbles (pezzetti rotolati) of quartz, of which it is essentially composed, pebbles of rock crystal are sometimes found in great abundance. For the most part they belong to the granite, quartzite, or porphyry, and vary greatly in size, increasing from that of a filbert to about two decimeters in diameter. In occasional instances they are found of a surprising magnitude; but these, as well as the smaller specimens, have a rounded surface. We may instance one, which was found above Monte Vergine, near Avellino, more than five decimeters in diameter; and another, in the region called Fontana delle Rose, not far from Muro, whose greatest diameter was sixty-three centimeters. This last region, made known by the published works of Tenore and Gussone, ought to be visited in preference to any other, by those who desire to examine the great rolled masses of granite which exist in our Apennines. On the road from Laviano to Atella, a little past the seventy-first milestone, we met on the right-hand side, a path leading to a spacious valley, through which the waters of the Fontana delle Rose run. Along this rough path we often meet with large granite boulders, and in the valley following the course of the stream, several large isolated ones may be found. Of these last there can be no doubt, that, like those still imbedded in the sandstone, they too were inclosed in the rock, and when it was disintegrated they remained scattered as we see them through the valley. Many such rolled masses of granite, and of another kind of crystalline rock, are found along the River Olivento, commencing at the source under Ripa Candida, and extending to its junction with the torrent of Macera; similar rocks are also found in other places surrounding the volcanic region of Vulture, or on the Vulture itself. We have seen