IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 13 



" Esna shales ", as a fades name, should be retained and thus proposed the term 



" Esna shale fades ", as an expression of certain lithological and palaeonto- 



logical characters of a part of the stratigraphic column in certain parts of Egypt." 



In all these studies the succession was only briefly described, and the limits of the 

 various stages and substages were vaguely defined. As a result the succession was 

 wrongly considered to be conformable throughout, and correlation with the type 

 sections or the known other sections outside theTethyan region could not be achieved. 

 Moreover, no palaeontological study was ever attempted and no geological map of the 

 region was published, except for a very small part in the neighbourhood of El-Kab 

 which was mapped by Schweinfurth (1904). The latter has only schematically 

 shown the distribution of what he described as Campanian, scattered, rolled 

 Eocene pebbles, and Pleistocene and Recent. A part of this map was used by 

 Nakkady (1951a) where the same mapping units were followed. 



In a recent geological study of the Esna-Idfu region, the present writer mapped 

 the area in detail. This mapping which has resulted in the classification of the 

 surface rocks into distinct litho- and bio-stratigraphical units, has also proved for the 

 first time, the existence of a distinct break between the Maestrichtian and the over- 

 lying Paleocene rocks. In spite of repeated emphasis on the absolute conformity of 

 the succession by previous workers, a conglomerate with reworked Upper Cretaceous 

 macrofossils was clearly observed in the field and a distinct faunal break was proved 

 by the study of the macrofauna and the planktonic Foraminifera. The existence of 

 such a stratigraphical break in a region where continuous deposition and absolute 

 conformity between the Cretaceous and Tertiary systems has been unquestionably 

 accepted, throws a new light on the geological history of Egypt during late Creta- 

 ceous and early Tertiary time. Moreover, comparison with various Upper Creta- 

 ceous-Lower Tertiary sections in Egypt has clearly indicated the existence of 

 stratigraphical breaks of varying magnitudes in areas where the succession was 

 described as conformable throughout. 



The detailed geology of the region is discussed elsewhere (El-Naggar, in manu.) 

 and the main objects of the present investigation can be summarized as follows : 



1. Stratigraphical analysis of the Upper Cretaceous-Lower Tertiary succession 



of the Esna-Idfu region on the basis of its lithology and macrofossil content, 

 and correlation with corresponding sections in other parts of Egypt. 



2. Analysis of the succession on the basis of its planktonic Foraminifera ; 



correlation with the planktonic foraminiferal zones in other parts of the 

 world, and the establishment of the ranges of the recorded macrofossil 

 species in the light of the planktonic foraminiferal zonation. 



3. Detailed systematic study of the planktonic Foraminifera. 



Methods of investigation. The Esna-Idfu region was geologically mapped, 

 using topographical sheets, scale 1 : 100,000 and aerial photographs, scale 1 : 40,000. 

 As stated above, the detailed geology of the region and the maps are discussed else- 

 where and only small scale reproductions of the maps are presented here (Text-figs. 2, 



