On a point on the east side are ruins of the fort and walls of Longonas, a Pisan town, destroyed by the Arragonese: it is thought by some to have been the Plubium of the ancients; but I found nothing indicating this as the identical spot, though, by inference, it must have been somewhere in the neighbourhood.

This cape was the Erebantium Promontorium of Ptolemy, and its western face is composed of strongly marked rugged cliffs, with several rocks above water, at its base, but nevertheless of deep approach.

On the north point is a cove, called Cala Spinosa, and near it are some quarries where fine granular stone may be obtained, and whence the columns were taken for the Pantheon at Rome, that most admirable specimen of ancient taste. Fifty or sixty large shafts, intended for columns and pilasters, with parts of a sarcophagus, were moved towards the beach, for exportation, and are still lying near the chapel of Santa Reparata.

In this incorrect production, the following note is placed near the centre of Gallura: “Icy se voyent les matrices des colonnes du Pantheon”, but how, from such an inland spot, the enormous masses were got down to the sea side, it would be difficult to explain.