144 DR. W. F. HUME ON SECULAR OSCILLATION IN EGYPT [Feb. I9II, 



Nubian at the base of the Campanian ; (2) a Middle Nubian above 

 the Turonian ammonite- bed ; and (3) a Lower Nubian below the 

 Cenoraanian strata and closely related to them. 



(c) A Central Egyptian or Hammama type, extending in 

 the Eastern Desert and on the Nile between latitudes 25° N. and 

 26° N. In this phase the Cenomanian and Turonian strata are 

 absent, the Nubian Sandstone forming the greater por- 

 tion of the Cretaceous System, with Santonian oysters 

 (0. boiiclieroni, 0. bourguignati) in its highest beds. The overlying 

 Campanian Series is characterized by the abundance of Ostrea villei, 

 Trigonoarca multidentata, and by phosphatic beds with Otodus 

 miriculatus. The Danian member has an eastern facies, in which 

 Pecten Marls are the principal feature, and a western (the Oasis 

 type), where a fauna of small gasteropoda, species of Echinocorys, 

 crinoids, and Terebratulina cf. gracilis, occurring in a chalky lime- 

 stone, indicate a close affinity to the "White Chalk of Northern 

 Europe. 



(d) A South Egyptian Cretaceous type has close resem- 

 blances to the Central Egyptian; but in the Campanian 

 the phosphatic beds are inconspicuous, and the fauna 

 consists of a group of small sea-urchins (mostly new species) and 

 of gasteropoda, among which large Turritellce are prominent. This 

 facies is developed at Dungul Oasis and in the Cretaceous ex- 

 posures on the Arbain road, south of Kharga Oasis. 



2. The Danian fauna of the oases (small gasteropoda and corals) 

 has been found east of the Nile near Esna in close relation to the 

 Pecten Marls, the Oases and Hammama types being thus linked 

 together. 



3. As a result of the Wadi Qena expedition of this year (1910), 

 the foregoing facts bear the strongest testimony to the Cretaceous 

 age of the Nubian Sandstone. 



B. — Regarding the transition from the Eocene to the Cretaceous, 

 we note : — 



4. The existence of two different types of strata at the base of 

 the Eocene, the first, or Luxor type, being characterized by the 

 abundance of Operculina libyca, large sea-urchins (Phabdocidaris, 

 etc.), and bivalves (Lvcina thebaica), almost immediately overlying 

 shales with the small Cretaceous (Danian) fauna : the second, or 

 Qena type, being, on the other hand, entirely unfossiliferous and 

 composed of white limestones having the closest lithological resem- 

 blance to the typical Danian white chalk with Pecten farafrensis 

 or P. mayer-eymari, etc. 



5. Though lithologically resembling the Danian limestones, those 

 of the Qena type, which underlie strata of proved Eocene age (con- 

 taining Nummulites variolarius and N. curvispira), are remarkably 

 jointed or honeycombed, and very susceptible to denudation, as shown 

 by the numerous caves, natural bridges, and cylindrical pipes formed 

 in them. 



As an explanation of these differences, it is suggested that these 



