IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 39 



rapidly, and this makes the use of planktonic species of rather limited value. The 

 only exceptions to this rule seems to be the Globotruncana and Giimbelina species, 

 which are assumed by many authors to have been planktonic " and added " .... we 

 have abandoned the classic and oft-repeated zoning based on the planktonic foramini- 

 fera Globigerina and Truncorotalia. We feel that these forms are facies fossils, 

 which, may have some zoning value but which occur, like their descendants in modern 

 times, only in open and moderately deep seas ". Thus, while at the beginning of their 

 work they followed Nakkady 's zonation of the Upper Cretaceous-Lower Tertiary rocks 

 of Egypt into a Globotruncana-Guembelina Zone of Maestrichtian age, a Globigerina 

 or Buffer Zone of Danian age, and a Globorotalia Zone of Paleocene age, they used 

 Bolivinoides and Neoflabellina for the classification of the succession, and thus confused 

 the correlation between the two sections. Without discussing the disadvantages 

 and mistakes of such a classification (e.g. their record of Neoflabellina rugosa, a 

 known Campanian form, in their Upper Maestrichtian, Danian and Paleocene), 

 these authors stated that " These species are, unfortunately, rare in the Egyptian 

 material and may escape notice ". However, other than the undisputed value of 

 Globorotalia in Lower Tertiary stratigraphy and correlation, the fallacy of the whole 

 picture presented by Said & Kenawy (1956) is clearly demonstrated by their text- 

 fig. 4. In this text-figure, the parallelism between their Globotruncana time surface 

 and their Truncorotalia surface, indicates that the folding movement which shaped 

 the strata of the two sections in their present day form, definitely took place after 

 the appearance of the sharply-keeled globorotalias, i.e. at least after the beginning 

 of the Upper Paleocene and not before the deposition of the Maestrichtian as suggest- 

 ed by these authors. Indeed, a similar folding movement which affected the Upper 

 Cretaceous-Lower Tertiary rocks of the Esna-Idfu region is of post-Lower Eocene 

 age. Nevertheless, this does not deny the possibility that the Upper Cretaceous 

 sea bottom was affected in certain regions by intermittent folding movements 

 (which might even have started long before the Upper Cretaceous), as suggested by 

 Hume (1911) and Shukri (1954), and substantiated by deep drilling in the northern 

 part of the Western Desert (see Said 1962). One of the most striking contradictions 

 in Said & Kenawy's discussion is their statement that " The Maestrichtian-Danian 

 boundary is therefore of importance in determining the structural position of the 

 locality from which a section was taken. When this boundary coincides with the 

 lithologic boundary between the chalk and the Esna shale, it indicates a structural 

 low, whereas its occurrence within the Esna shale indicates a structural high in the 

 late Cretaceous sea. This idea is further strengthened by the fact that we find the 

 thinnest Danian, followed immediately by the Truncorotalia zone, in the structurally 

 low areas ". Contrary to this conclusion, the present study has shown that the 

 variation in the thickness of the Danian strata, which are generally of the same 

 lithological composition, is mainly due to the occurrence of stratigraphical breaks of 

 varying magnitude between the Maestrichtian and the overlying Paleocene, and that 

 the thinnest Danian occurs in areas which were subjected to more uplift and/or more 

 erosion, not in the structually low areas, as suggested by these authors. On the 

 other hand, correlation with the succession in the Esna-Idfu region shows clearly 



