_Cælosmilia_. | _Exogyra overwegi_. | _Linthia_ nov. sp. | _Pecten farafrensis_. | _Spirorbis_. | _Spondylus_ nov. sp. aff. _S. Dutempleanus_. | _Inoceramus_. | _Nautilus_ sp. | _Gryphæa vesicularis_ | _Corax pristodontus_. As regards the age of this White Chalk the fossil facies has a very young Cretaceous aspect. Zittel[50] has already shown that the White Chalk of the Libyan Desert, studied by him in Farafra, Dakhla and Kharga, is Danian, and the identity of the chalk of Baharia with that of those oases was satisfactorily proved on the traverse from the latter oasis to Farafra. The White Chalk brings our description of the Cretaceous series of Baharia to a close. As will be shown, it is overlain unconformably by Eocene deposits. Throughout the deposition of the Cretaceous in this area it is clear from the character of the beds that the sea-floor had been continually sinking. After the deposition of the white chalk subsidence probably ceased and the area became one of elevation, the Cretaceous beds rising to form land. During this elevation much folding must have taken place, and subsequently gradual subsidence set in until in Lower Eocene times the area again became marine and the deposition of the rocks now to be described began to take place. * * * * * EOCENE. UPPER LIBYAN—LOWER MOKATTAM.[51] 4. _Limestones with Nummulites and Operculina_.—In the north part of the oasis, both in the walls and in the isolated hills within the depression, the lower Cenomanian beds, the “Sandstones, clays and marls,” are directly overlain by buff-coloured or yellowish limestone of Eocene age, containing _Nummulites_, _Operculina_, _Ostrea_, etc. The beds of the two series being horizontal, the junction is one of apparent conformability, but in many localities the base of the Eocene is marked by a bed of limestone-grit, indicating the break in continuity of deposition which is known to have occurred from the respective ages of the beds in question and from a study of the same beds further to the south. In a traverse across the plateau to the west of Bawitti, Operculina-limestones with nummulites were found to form the surface of the desert. Again on the traverse from Maghagha to the oasis, already described, no Cretaceous beds were crossed, so that the plateau N.N.E. and N.W. of the northern end of the oasis is entirely formed of Eocene rocks. On the east side, however, no certain evidence of Eocene age in the beds capping the scarp has been found south of the fault which cuts the scarp as the prolongation of the sharp syncline of Jebel Hefhuf.