One of the hills within the depression, to the left of the track about 6 kilometres further on, showed in a face of about 28 metres the following beds:— _Top._ 1. Hard white limestone, sand-eroded. 2. Brown fossiliferous limestone. 3. White limestone with many small fossils. The slopes of this hill were covered with large black _Ostrea_ shells. The floor of the depression further west showed limestones of varying character, frequently highly fossiliferous. Beyond the depression the ground passed over was mainly white limestone, strewn with large sharp angular flints, and many spheroidal flint-masses derived from the limestones. The surrounding hills show that we have here two white limestones with brown beds between, the floor and the hillcaps being white, while the feet of the hills are brown. The plateau-rock near the great belt of sand-dunes is a hard white limestone with large _Conidæ_. Just beyond the dunes this rock is very siliceous, the exposed surfaces showing a smoky-black colour; the rock is however quite white on fracture. The hills rising from the plateau here consist entirely of limestone, beds of white chalk alternating with harder yellowish and brown limestones, in which no fossils were noticed. Further on the plateau rises, so that at the entrance to the depression the surface is formed of the same brown limestone-beds which are seen in the hills behind. The hills within the oval depression here are composed of alternations of chalky with harder limestones. The narrow ridge which separates the depression just described from the oasis-depression is of very hard horny siliceous limestone. On the descent into the oasis the following beds are passed through:— _Top._ 1. Very hard yellowish and reddish-brown siliceous limestone, in part crystalline. 2. Fissile sandy limestone. 3. Soft yellow ochreous marly limestone. 4. Greyish-white chalky limestone, with ferruginous layers. 5. Sand-covered slope, mainly consisting of clays. It seems probable that the entire mass of the limestones forming the surface of the plateau are Eocene, occupying an horizon in and below that of the Mokattam series. That the fissile sandy limestone and calcareous grit cannot be the equivalent of the Post Eocene sandstone deposits encountered on the road from Maghagha is proved by their being intercalated in the Eocene limestones of the plateau. [Sidenote: Traverse from south end of Baharia to Minia.]