60 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



tions are also discussed whenever necessary and the confusion surrounding the species 

 is explained in detail wherever possible. 



Species of Globotruncana, Globorotalia and Globigerina are described and figured in 

 detail except for a few that are very rare. Species of Abathomphalus, Rugoglobi- 

 gerina, Trinitella and Hedbergella are only listed and will be dealt with in detail in a 

 future publication, together with other planktonic Foraminifera such as Globigerinel- 

 loides, Pseudotextularia, Pseudoguembelina, Guembelina, Planoglobulina, Racemig- 

 uembelina and Heterohelix. Consideration of the ranges of these planktonic Foramin- 

 ifera has led to the recognition of seven faunal zones and four subzones ; in addition, 

 three other zones, which are either devoid of planktonic Foraminifera, or contain rare 

 indeterminable forms, have also been recognised. (Text-figs 5 and 6). These zones 

 and subzones are correlated with the corresponding macrofossil zones and subzones 

 (Text-fig. 5), and with various planktonic foraminiferal zones in other parts of the 

 world (Text-fig. 6), they are briefly discussed below and are from the base upwards, as 

 follows : 



1. A non-fossiliferous zone. 



2. A zone with rare indeterminable planktonic Foraminifera. 



3. The Globotruncana fornicata Zone. 



4. The Globotruncana gansseri Zone. 



5. The Globotruncana esnehensis Zone. 



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6. The Globorotalia compressa/ Globigerina daubjergensis Zone. 



7. The Globorotalia angulata Zone. 



a. The Globorotalia uncinata Subzone. 



b. The Globorotalia pusilla Subzone. 



8. The Globorotalia velascoensis Zone. 



a. The Globorotalia pseudomenardii Subzone. 



b. The Globorotalia aequa / Globorotalia esnaensis Subzone. 



9. The Globorotalia wilcoxensis Zone. 



10. A zone with indeterminable planktonic Foraminifera. 



1. A NON-FOSSILIFEROUS ZONE. 



This zone coincides with the Nubia sandstone and variegated shale formation 

 which is mostly devoid of fossils except for rare plant and vertebrate remains. 

 Several samples were washed for foraminiferal investigation, but no Foraminifera 

 were observed. 



2. A Zone with rare indeterminable planktonic Foraminifera. 



This zone coincides with the Sibaiya phosphate formation which contains extreme- 

 ly minute forms of Foraminifera, that could only be seen in thin section and thus 

 could not be identified with certainty. 



3. The Globotruncana fornicata Zone. 



This represents the lowest recognized planktonic foraminiferal zone in the succes- 



