IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 65 



G. angidata abundocamerata, G. apanthesma, G. berggreni, G. cf. convexa, G. emilei, 

 G. esnaensis, G. faragi, G. hispidicidaris, G. irrorata, G. woodi, G. nicoli, G. occlusa, 

 G. perclara, G. pseudomenardii , G. pusilla mediterranica, G. sibaiyaensis, G. tribulosa, 

 G. whitei, as well as the rare occurrence of G. imitata, G. pusilla pusilla, G. pusilla 

 laevigata, G. quadrata, G. pseudobidloides and G. sp. at its base, and G. wilcoxensis, 

 G. loeblichi, G. troelseni at its top. 



It is also characterized by the abundance of the following Globigerina species : 

 G. aquiensis, G. bacuana, G. chascanona, G. haynesi, G. inaequispira, G. mckannai, 

 G. nodosa, G. soldadoensis, G. spiralis, G. stonei, G. triloculinoides , G. triloculinoides 

 parva, G. velascoensis and G. alanwoodi. 



The G. velascoensis Zone is clearly divisible, on the basis of its planktonic Fora- 

 minifera, into two distinct subzones : a lower G. pseudomenardii Subzone and an 

 upper G. aequajG. esnaensis Subzone. The lower subzone is distinguished by its 

 index species, G. pseudomenardii Bolli, which does not range into the overlying 

 subzone. The G. aequajG. esnaensis Subzone is also characterized by its index 

 species which do not range into the underlying subzone, although rare forms of 

 G. aequa may be recorded in the uppermost part of the underlying subzone. The 

 distribution of the various planktonic foraminiferal species in each of these subzones 

 is clearly shown on Text-figs. 12-16. 



The G. velascoensis Zone corresponds to the Ostrea hypoptera Zone and the lower 

 part of the non-megafossiliferous zone in the macrofossil zonal scheme. On the 

 basis of its planktonic foraminiferal content, and stratigraphical position, it is 

 considered to represent the Upper Paleocene as stated above (see pp. 29-31, 49-51). 



9. The Globorotalia wilcoxensis Zone. 



This represents the last planktonic foraminiferal zone in the succession studied. 

 It coincides with the Thebes calcareous shale member and probably includes at 

 least part of the overlying Thebes limestone member, although the latter did not 

 yield any identifiable planktonic Foraminifera. It is characterized by the abun- 

 dance of Globorotalia wilcoxensis Cushman & Ponton, which is considered as the 

 index species of this zone. 



The lower limit is marked by the disappearance of the following Globorotalia 

 species : G. velascoensis velascoensis, G. acuta, G. angidata angulata, G. apanthesma, 

 G. cf. convexa and G. nicoli as well as by the disappearance of the following Globi- 

 gerina species : G. bacuana, G. chascanona, G. haynesi, G. inaequispira, G. triloculi- 

 noides, G. triloculinoides parva, and G. velascoensis. It is also marked by the first 

 appearance of G. bollii and the flood of G. wilcoxensis. The upper limit of the zone 

 is not really known in the succession studied, as no younger zones have yet been 

 recorded. 



The G. wilcoxensis Zone is characterized by a flood of G. wilcoxensis, which species, 

 though appearing first as rare, scattered individuals in the uppermost part of the 

 underlying zone, is nevertheless considered to be a good index fossil. The zone is also 



