I know and can tell the names of all the peoples that live on the ridge as far as the Atlantes, but no farther than that. But I know this, that the ridge reaches as far as the Pillars of Heracles and beyond them. There is a mine of salt on it every ten days' journey, and men live there. Their houses are all built of blocks of the salt; for these are parts of Libya where no rain falls; for the walls, being of salt, could not stand firm if there were rain. The salt there is both white and purple. Beyond this ridge, the southern and inland parts of Libya are desolate and waterless: there are no wild beasts, no rain, no forests; this region is wholly without moisture.