66 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



characterized by the abundance of the following Globorotalia species : G. troelseni, 

 G. whitei, G. bollii, G. aequa, G. esnaensis and G. loeblichi, as well as by the abundance 

 of both Globigerina stonei and Globigerina soldadoensis, and by the rare occurrence at 

 its base of both Globigerina mckannai and Globigerina aquiensis. 



The G. wilcoxensis Zone corresponds to the upper part of the non-megafossiliferous 

 zone and possibly the lower part of the overlying Lucina thebaica Zone, in the macro- 

 fossil classification. On the basis of its planktonic Foraminifera, and stratigraphical 

 position, it is considered to mark the dawn of the Eocene as discussed above (see 

 pp. 31, 32, 51, 52). 



10. A ZONE WITH INDETERMINABLE PLANKTONIC FORAMINIFERA : 



This zone coincides with the Thebes limestone member, of which only the lowest 

 ten metres crop out in the area studied. This hard, siliceous limestone bed which 

 caps the succession is flooded with Nummulites, Operculina, Assilina, Discocyclina, 

 etc., but has not yet yielded any identifiable planktonic Foraminifera, possibly 

 because of its silicification. Several samples of this bed are now being processed for 

 planktonic foraminiferal analysis using different techniques with the hope of recover- 

 ing some identifiable forms. 



These planktonic foraminiferal zones clarify the stratigraphy of the Upper Creta- 

 ceous-Lower Tertiary in Egypt, and their recognition in other parts of the world 

 indicates that they can be successfully used for the zonation and world-wide correl- 

 ation of strata of this age. 



V. SYSTEMATIC DESCRIPTIONS 



Order FORAMINIFERIDA 



Superfamily GLOBIGERINACEAE Carpenter, Parker & Jones 1862 



Family GLOBOTRUNCANIDAE Brotzen 1942 



This family is represented in the present study by the four genera, Globotruncana 

 Cushman 1927, Rugoglobigerina Bronnimann 1952, Trinitella Bronnimann 1952, and 

 Abathomphalus Bolli, Loeblich & Tappan 1957. Forty-five species and subspecies of 

 Globotruncana, seven species of Rugoglobigerina, one species of Trinitella, and two 

 species of Abathomphalus are recorded. Members of the genus Globotruncana are 

 discussed in detail, while those of Rugoglobigerina, Trinitella and Abathomphalus are 

 only listed and will be figured and described in a later publication. 



Genus ABATHOMPHALUS Bolli, Loeblich & Tappan 1957 

 Type species : Globotruncana mayaroensis Bolli 195 1 



Abathomphalus intermedia (Bolli) 



195 1 Globotruncana intermedia Bolli : 197, pi. 35, figs. 7-9. 



1954 Globotruncana intermedia Bolli ; Ayala : 399, pi. 7, figs. 2a-c. 



