IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 55 



12. G. colligera (Schwager) var. crassaformis (Galloway & Wissler) is G. wilcoxensis 



Cushman & Ponton. 



13. G. crassata var. aequa Cushman & Renz includes Globorotalia rex Martin, 



G. aequa Cushman & Renz and other unknown forms. 



14. G. deceptoria (Schwager) includes various forms of Globigerina and Globorotalia 



e.g. Globorotalia aequa Cushman & Renz, G. wilcoxensis Cushman & Ponton, 

 and G. whitei Weiss ; Globigerina stonei Weiss, and G. valascoensis Cushman. 



15. G. simulatilis (Schwager) includes Globorotalia rex Martin, G. occlusa Loeblich 



& Tappan, G. velascoensis parva Rey, G. cf. pseudoscitula Glaessner, G. 

 emilei sp. nov., and G. cf. angulata abundocamerata Bolli. Again, G. 

 simulatilis was recorded from younger strata, and its holotype needs to be 

 redrawn and redescribed in more detail. 



16. G. velascoensis (Cushman) includes G. velascoensis velascoensis (Cushman), 



G. cf. angulata angulata (White), G. cf. angulata abundocamerata Bolli, 

 G. cf. pseudoscitula Glaessner, and G. cf. occlusa Loeblich & Tappan. 



Nevertheless, on the basis of these few planktonic forms, Nakkady established 

 three biozones in the Mesozoic-Cainozoic transition beds of Egypt : a Globotruncana 

 Zone of Maestrichtian age, a Globorotalia Zone of Paleocene age and an intervening 

 Buffer Zone of Danian age, distinguished by the complete absence or extreme 

 scarcity of both Globorotalia and Globotruncana. 



Nakkady's pioneering attempt was mainly based on genera, and as the planktonic 

 Foraminifera are known to exhibit an abrupt change in their generic composition at 

 the Cretaceous-Tertiary boundary all over the world, his Maestrichtian-Danian 

 boundary was correctly drawn. However, he neither recognized the Tertiary 

 character of the Danian fauna, nor the obvious stratigraphical break between the 

 Upper Cretaceous and the basal Tertiary, which can be easily seen on his chart 

 (1951a), where his Buffer zone was shown to vary greatly in thickness. Moreover, 

 in his later studies, Nakkady confused the limits between the various stages of the 

 Paleocene and between the Paleocene and the overlying Eocene. Nevertheless, his 

 faunal sequence (a Globotruncana Zone, followed by a Buffer or Globigerina Zone and 

 a Globorotalia Zone, for the Maestrichtian, Danian and Paleocene respectively) has 

 since been observed in many parts of the world and has been used as a basis for the 

 precise zonation of the Cretaceous-Tertiary succession. 



Nakkady (1959) recorded the following planktonic Foraminifera from what he 

 considered as Maestrichtian-Montian of the Um Elghanayem section, Kharga Oasis, 

 Egypt : Globotruncana aegyptiaca Nakkady, G. quadrata Nakkady & Osman ; 

 Globorotalia angulata (White), G. crassata var. aequa Cushman & Renz, G. deceptoria 

 (Schwager), G. pseudomenardii Bolli, G. quadrata Nakkady & Talaat, G. simulatilis 

 (Schwager), G. velascoensis (Cushman) ; Globigerina esnaensis Le Roy, G. mckannai 

 White, G. pseudobulloides Plummer, G. quadrata White, and G. triloculinoides 



