In Venezuela is the celebrated cave of Guacharo, among the loftiest precipices of the mountain range; the entrance being through a gloomy ravine, running above a subterranean stream, the banks of which are covered with luxurious vegetation. Guacharo, as the name implies, is the resort of immense quantities of night birds, and their harsh notes resounding through its dismal recesses gave it the reputation, with the ignorant natives, of being the abode of the devil and his imps. For generations they have had traditions of dreadful ceremonies and hideous orgies held there, and have believed that many wicked persons have been seized by the imps, carried into and tortured in those awful recesses. They would not enter the cavern for any earthly consideration, sincerely believing that to do so would insure the loss of their souls. Humboldt, so far as known, was the first man who ever set foot within Guacharo; and he then succeeded, after unwearied patience and perseverance, in inducing a certain number of natives to accompany him as guides. They had not proceeded far, however, when the clamor of the birds so terrified them that they fled, in spite of every effort of the great naturalist to calm their superstitious fears. Near Iletski, in Russia, is a freezing cave, so called because, reversing the order of the seasons, it is partially filled with ice in the summer, and altogether free from ice in the winter. Not a few of the caverns of the old world have been found to contain the bones of extinct species of animals. One of these, at Kirkdale, in Yorkshire, was discovered about half a century ago, and in it were quantities of remains of bears, lions, tigers, hyenas, and hippopotami, all of orders that had passed away. It is presumed that the Kirkdale cave was for a long while a vast den of hyenas, and that some great inundation destroyed them and their kind. [Sidenote: THE GREATEST CAVE IN THE WORLD.]