[13] To what we cited before concerning the temple of Ammon and Egypt, Eratosthenes adds, that to judge from appearances, Mount Casius
1
was formerly covered by sea, and the whole district now known as Gerra lay under shoal water touching the bay of the Erythraean Sea,
2
but was left dry on the union
3
of the [Mediterranean] Sea [with the ocean]. A certain amphibology lurks here under this description of the district lying under shoal water and touching the bay of the Erythraean Sea; for to touch
4
both means to be close to, and also to be in actual contact with, so that when applied to water it would signify that one flows into the other. I understand him to mean, that so long as the strait by the Pillars of Hercules remained closed, these marshes covered with shoal-water extended as far as the Arabian Gulf, but on that passage being forced open, the Mediterranean, discharging itself by the strait, became lower, and the land was left dry.