CHAPTER XXXIX.
A RIDE ROUND VULTURE AND UP TO MONTICCHIO.
I left in the afternoon for Monticchio monastery, situated close above the lakes of the same name, that fill two of the ancient craters upon the west side of the Vulture.
Leaving Rionero, we ride across the rich and nearly level plain of about 212 miles wide, all sown with even now sprouting grain, and have to make many detours, to pass the deep and wall-sided chasms, or "nullahs," that are cut into the mass of tufa underlying it, by the rain torrents descending from the flanks of the cone. (Fig. 324.) Many of these torrent courses are 50 to 100 feet in depth, and some not 30 feet across, though generally they are more; the sides are perfectly plumb, or shed in and sloped here and there, tortuous and winding in plan. The bottom is generally quite flat, and not above 10 or 15 feet wide between the high side banks of tufa, strewed with large lapilli, fragments of lava, numbers of limestone pebbles, and a fine black sand, of titanate of iron, which is deposited in whole banks in some places.
These chasms are almost invisible at a short distance, and perfectly impossible to be crossed when deep. On
