station on Monte Colibre, is Galiano, a high perforated rock resembling a ship under full sail; and several rocks and reefs stretch more than half a mile to the eastward of it, against and over which the sea breaks very heavily in gales. Nearly in mid-distance between Galiano and Malaspina lies Ferrer, a remarkable quoin-shaped phonolitic rock, with smaller ones in its vicinity; so that the Columbretes are divided into four detached clusters, with deep water in the channels between them. The approach on all sides is extremely bold, and the soundings gradual, diminishing from fifty fathoms, over a bottom of brown sand and broken shells, at three or four miles off, to forty and twenty in the passages between the rocks, except where Fidalgo, Lopez, and Luyundo reefs are placed. Even between Ferrer and Joachim, there are no less than thirty fathoms of depth.
The whole of these volcanic fragments consist of similar materials; and amongst the specimens which I brought away are compact lavas, some of which are speckled with white calcined substances, while others contain black acicular crystals, and numerous small clusters of brilliant yellow ones; the former having probably lost their water of crystallization from intense heat, and the latter been formed by the condensation of vapours in the cavities of inflated lavas, on cooling. Intermixed with the scoriae—which are highly tinged with iron, and so cellular as to resemble coarse pumice—are numerous masses of amorphous schorl; and both hyperstone and pearlstone occur.
The geological relations of these islets, however, are not the only interesting points relating to them: their ancient nomenclature requires also some elucidation. It is known that the Greek geographers applied the name of Ophiusa to an Iberian island, from its abounding with serpents, and that the Romans, for the same reason, called it Colubraria; but the identity of the place has rather been inferred than ascertained—custom having long conferred the name on Formentera; and, to countenance the application, we have been gravely told of the myriads of snakes which have caused it to remain uninhabited. But a visit to the spot proves the misnomer; for from its population (despite of Aigerine ravages) and its culture, together with the numerous vestiges of matamore granaries, it is readily seen that the present appellation has been a consequence of the excellence of its corn harvests. Iviza, or Ibiza, the Ebusus of Strabo, and Ebyssus? of Ptolemy, was undoubtedly called Pityusa major, and Formentera Pityusa minor,—names which they deserve still from their resinous pine-trees; and the peculiar boast of the natives is, that no venomous reptile can live in Formentera, whether from the presence of the semper virens, one of the snake-roots of antiquity, or that their earth has the quality of destroying serpents, as Pliny records that of Ebusus to
