North of Silsila in the Nile valley the sandstones gradually give way to a series of flaggy ripple-marked sandstones alternating with sandy shales and clays, at the top of which are beds rich in bones and coprolites of fish, associated with hard oyster-limestones, overlain in Wadi Hammama, E.-N.-E. of Qena, by a limestone containing abundant remains of cephalopoda; these beds are of Upper Senonian (Campanian) age. East of Sabaia, in the Nile valley, they are followed by a 200 metre series of finely laminated clays, separated by bands of marly limestone, the greater part of which is of Cretaceous age and homotaxial with the _Exogyra_ clays and white chalk (of Campanian--Danian age) which in the southern oases follow on the rich bonebeds overlying the Nubian Sandstone. Anterior to and during the deposition of these clayey beds in the south, thick accumulations of limestone were being formed in the more open sea to the north and are visible to-day in the Cretaceous area of Abu Roash near the pyramids of Giza, (and to a lesser extent in Jebel Shebrewet on the Gulf of Suez), where a great complex of limestones of Turonian and Senonian ages occurs. Finally a deep sea deposit of white chalk forms the summit of the Cretaceous throughout the Western Desert. 49. =Eocene.= Our knowledge of the junction of the Cretaceous and Eocene in several parts of the country leaves much to be desired. Where the Eocene is most fully developed its basal member consists of a group of green argillaceous deposits, known as the Esna shales, well seen at the base of the cliffs throughout the Esna-Qena reach of the valley. These beds everywhere pass conformably upwards into the Lower Eocene (Libyan) limestones above, but in the Nile Valley and the Eastern Desert the exact line of demarcation between them and the lithologically similar Cretaceous clays below is still somewhat obscure. In Kharga and Farafra they form a well-marked band between the White Chalk (and associated clays) at the top of the Cretaceous and the Libyan limestone of the Lower Eocene. The Esna shales may in fact be regarded as passage beds, and where they exist appear to bridge over the lapse of time which is represented by a decided unconformity between the Cretaceous and Eocene in the north of the country, as in Baharia Oasis and at Abu Roash.