I" UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



" Sibaiya formation ". 3 Moreover, as no stratigraphical breaks were observed within 

 the part of this formation, outcropping in the Esna-Idfu region, the author is 

 inclined to include the outcropping part of the Nubia formation in the Esna-Idfu 

 region, in the Campanian. However, as there is no direct evidence, the age of this 

 formation is here considered to be Campanian and ? pre-Campanian. 



(2) The Sibaiya Phosphate Formation 



Despite the fact that the Sibaiya formation did not yield any identifiable plank- 

 tonic Foraminifera, and that its macrofauna does not provide a direct means for 

 correlation with the type sections in Europe, it is here considered to belong to the 

 Upper Campanian for the following reasons : 



(a) Blanckenhorn (1921) and Hassan (1956) recorded Bostrychoceras polyplocum 



Roemer, an index fossil for the Upper Campanian in its type section and 

 elsewhere, from the same formation in other parts of Egypt, and with a 

 typically similar association of fauna. 



(b) The Sibaiya formation is conformably overlain by the " lower Sharawna shale 



member ", which is characterized by the first appearance of Terebratulina 

 gracilis Schlotheim, an index fossil for the base of the Maestrichtian. 

 Terebratulina gracilis was also recorded from Lower Maestrichtian strata 

 conformably overlying the " Bosytrchoceras polyplocum s.l. Zone " in Germany 

 (Schmid, Hiltermann & Koch 1955) ; in Palestine (Parnes 1956) ; in Holland, 

 Belgium and in the Aquitaine Basin of France (Upper Cretaceous Stratigraphic 

 Commission, International Geological Congress ; in Reiss 1962 : 4). 



(c) Most of the recorded Pelecypod fauna was considered by the various authors 



(including Coquand, the creator of the Campanian substage) to be mainly of 

 Campanian age, although a few forms may continue into the overlying basal 

 Maestrichtian. On the other hand, the varied vertebrate fauna of the 

 Sibaiya phosphate formation occurs in Europe in strata of Coniacian to 

 Campanian age (e.g. Siegfried 1954, 1956). 



(d) The Sibaiya formation is conformably overlain by two successive planktonic 



foraminiferal zones which are considered, by correlation with similar zones 

 in other parts of the world (Text-figs. 5, 6), to represent the Lower and 

 Middle Maestrichtian respectively. 



(e) In spite of its small thickness, the Sibaiya formation, as a chemically formed 



deposit, represents a relatively long period of time and an enviroment of 

 deposition, completely different from that of the overlying shales. 



(f) The Sibaiya phosphate formation can be correlated with similar deposits 



in the Kharga and Dakhla Oases, Qift and Quene areas, Kosseir and Safaga 

 districts and with corresponding deposits in the Middle East and North 

 Africa which are regarded as Upper Campanian. 



3 The close similarity of the vertebrate remains in these two formations suggested their inclusion in 

 one group of rock units, here termed the " Nubia group ", and is discussed elsewhere (El-Naggar, 

 in manu.). 



