34 ll'l'ER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



ian, probably including it within the Campanian, and considered the Danian as the 

 youngest stage of the Cretaceous system, but he did not state to which system his 

 " Passage beds " belong. Thus he assigned the oyster limestone and the associated 

 bone beds, which directly overlie the Nubia sandstone, to the Campanian, and the 

 overlying succession of shales, marls and chalks to the Danian which he correlated 

 with Zittel's Danian of the Western Desert Oases. He regarded the shales between 

 the top of the Danian and the base of the nummulitic limestones above, (Beadnell's 

 Esna shales) , as passage beds between the Cretaceous and the Teritary and referred 

 the overlying nummilitic limestones to the Lower Libyan (Lower Eocene) (see 

 Text-fig. 4). 



Hume (191 1) classified the same succession as Campanian, Danian and Lower 

 Eocene, including Beadnell's Passage beds within his Danian. He correlated this 

 succession with others in the Western Desert Oases, in Wadi Quena and in northern 

 Sinai. He also used these widely-spaced sections to demonstrate the gradual advance 

 of the Upper Cretaceous sea over the Egyptian territory, invading it from the north- 

 east, depositing limestones in the northern part, sandstones in the south, and shales, 

 marls and chalks in between. The relative distribution of these facies both in 

 space and time clearly marks the gradual invasion of the sea, and was used by 

 Hume as a means for classifying the Upper Cretaceous rocks of Egypt into five main 

 types from the north southwards. He suggested that folding towards the end of 

 Cretaceous times led to the formation of a series of parallel ridges rising from the 

 bottom of the Upper Cretaceous sea as islands or submarine ridges. Along these, 

 erosion took place, while deposition continued in the troughs in between ; hence 

 the existence of unconformities and disconformities between the Cretaceous and the 

 Tertiary systems along these ridges, and continuous depositon in the basins separa- 

 ting them. However, the controversy about the nature of the Cretaceous-Tertiary 

 boundary continued, and the vast concept of Zittel's Danian was followed until the 

 use of Foraminifera modified the old beliefs and introduced new and revolutionary 

 concepts. 



On the basis of small Foraminifera, Henson (1938) established two zones in the 

 Upper Cretaceous-Lower Tertiary succession of Palestine and adjoining countries 

 (including Egypt), a lower " Globotruncana-Guembelina Zone " of Upper Cretaceous 

 age, and an upper " Globigerina-Globorotalia Zone, of transitional character between 

 the Cretaceous and the Tertiary. He regarded this transitional zone as extending 

 from the highest Danian into the early Eocene, and considered the junction between 

 these two zones as " a reasonable approximation of the Cretaceous-Eocene contact ". 

 In other words, he considered the Globotruncana-Guembelina Zone to represent the 

 Danian (although the genus Globotruncana does not occur in the Danian) and the 

 Globigerina-Globorotalia Zone to represent the early Eocene, apparently including the 

 Paleocene. Moreover, he noticed that, even when there is no evidence of a break in 

 sedimentation between the Cretaceous and Eocene systems, the fauna of the trans- 

 itional zone is not equally developed in the various sections examined, and thus he 

 concluded that an imperceptible gap between the Cretaceous and Eocene systems 

 must exist. 



