Note 65 — PART III.

Mayer-Eymar appears to believe the depression of the Fayûm is the result of the volcanic activity which produced these basalt flows. He says (op. cit. Nouvelles recherches, etc., p. 218.) “Or, de cette extension extraordinaire du phénomène volcanique dans l’ouest du grand désert, il est, en premier lieu, permis de conclure que c’est par suite de son action excavante qu’a eu lieu l’effondrement rempli de nos jours, en partie par le lac de Fayum.”

Personally, we cannot see the slightest evidence in support of this. Where the basalt occurs as a hard band it usually causes steep cliffs as at Widan el Faras, owing to its protecting the underlying beds from denudation. To the west, in Jebel el Qatrani, its thickness and hardness determine the character and steepness of the escarpment below.