Vol. 67.] DURING THE CRETACEOUS AND EOCENE PERIODS. 119 



where these are necessary to complete the consideration of areas 

 which have not been personally investigated. The portions of 

 Egypt which have thus come under personal study are : — 



(1) Eastern Sinai. 



(2) A longitudinal region bordering Wadi Qena. 



(3) The area between latitudes 25° N. and 28° N. covered by the Eastern 



Desert Survey Memoirs of 1903 and 1906. 



(4) The districts bordering the Nile between Esna and Aswan. 



(5) A series of traverses across the Western Desert between the Oases of 



Dungul, Kurkur, Ivharga, and the city of Edfu, with a brief study of 

 the Arbain road south of Kharga. 



(6) Traverses from the Nile to Baharia, embracing visits to the Moela 



Oasis and the Fayum. 



(7) Studies in the neighbourhood of Cairo (Moqattam Hills, Abu Eoash, 



Helwan, etc.). 



Owing to results obtained during 1910, it is no longer possible, 

 in my opinion, to treat the Nubian Sandstone and the fossiliferous 

 Cretaceous strata as separate entities, but they should now be con- 

 sidered as parts of a single series. From this remark the Carbo- 

 niferous sandstone and limestone present in Wadi Araba and 

 Western Sinai must be excluded, as these contain Carboniferous 

 fossils. As no fossils of this age have at present been noted else- 

 where in Egypt, it is probable that these strata have only a limited 

 development. 



II. Variations in the Fossilieerous Cretaceous Strata, and 

 their Relation to the Nubian Sandstone. 



The gradual advance of the sea over many continental lands 

 during the Upper Cretaceous Period is one of the best established 

 of geological hypotheses, and Egypt contributes a striking illus- 

 tration of this general tendency. The predominance of deep-water 

 conditions in the north is witnessed by the deposition of limestones 

 throughout the whole of Upper Cretaceous times ; only farther south 

 is the presence of continental areas indicated by the occurrence 

 of the well-known Nubian Sandstone, which, of relatively minor 

 importance in Northern Egypt, in the south is the dominant 

 member of the Cretaceous System. Several phases may be 

 recognized, in which the organic and detrital deposits differ con- 

 spicuously as regards their distribution in time and space, marking 

 successive stages in the gain of sea over land. The Cretaceous 

 strata here considered consist of (1) the Danian, (2) the Campanian 

 and Santonian divisions of the Senonian or Upper Chalk, (3) the 

 Turonian or Middle Chalk, and (4) the Cenomanian or Lower Chalk. 

 The French terms will be used throughout this paper. 



