closed-in hollow, between smaller lateral valleys running nearly north and south, and opening in common upon the course of the Tanagro, in which Auletta and Pertosa, each perched upon a separate spur or colline, and each in the mouth of a separate but closely adjacent valley, are situated.
Upon the south-east, this hollow is completely barred and closed in, by the mountain of Taliata at the west, and the ridges of Monte Sarconi on the east, which abut upon each other, with nothing intervening but the tremendous cleft, through which one portion of the Tanagro forces its way from the north end of the Piano di Diano; while another portion of it, disappearing there, finds its way by a subterraneous channel, nearly parallel with that sub dio, and both meet again at Pertosa; the subterraneous waters discharging from the mouth of St. Michael's Cave, at a level of about 200 feet above the open bed of the river, opposite Pertosa, and turning the wheels of some old Catalan iron forges, before falling into it.
Although from this point the Tanagro pursues the same direction, as lower down, nearly from E. S. E. to W. N. W., the whole character of the valley itself has changed since passing Castelluccio, it is no longer a great E. and W. valley, but an irregular deep hollow, produced by the abutting and inosculation, of several secondary mountain ranges and valleys, running more or less N. and S., and gradually shutting up the hollow, until Auletta and Pertosa seem enclosed within it.
