IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 257 



9. The Paleocene-Eocene boundary is marked by the upper limit of the Globo- 

 rotalia velascoensis Zone. 



10. The Thebes Limestone and Calcareous Shale formation is of Lower Eocene 

 age. It is naturally classified into : a lower, " Thebes Calcareous Shale member ", 

 and an upper, " Thebes Limestone member ", which forms the top part of the 

 succession in the region. The former member is devoid of macrofossils except for 

 rare dwarfed forms seen only in washed residues. It is characterized by the Globo- 

 rotalia wilcoxensis Zone which is taken to mark the basal Eocene in Egypt and in 

 other parts of the world. The latter member corresponds to the Lucina thebaica 

 Zone of the macrofossil zonation. It is flooded with larger Foraminifera such as 

 Nummulites, Operculina, Assilina, Discocyclina, etc., but, because of its silicification, 

 it has not yet yielded any determinable planktonic forms. Nevertheless, its lower 

 part, most probably, still belongs to the G. wilcoxensis Zone. 



B. General conclusions. 



1. The Maestrichtian is considered to be a distinct stage in Upper Cretaceous 

 stratigraphy, younger than, and equal in rank to the Senonian stage, while the 

 Campanian is considered to be the upper substage of the Senonian as previously 

 suggested by Jeletzky 1951. 



2. The Campanian-Maestrichtian boundary is drawn at the top of the Bostry- 

 choceras polyplocum Zone = the Lopha villei Zone = the Globotruncana calcarata 

 Zone which marks the top of the Campanian in different parts of the world. 



3. The Maestrichtian is divided on the basis of its planktonic Foraminifera into 

 three successive zones ; the Globotruncana fornicata Zone, the Globotruncana gansseri 

 Zone and the Globotruncana esnehensis Zone. The lowest zone is younger than the 

 Upper Senonian in its type sections, while the upper zone is correlated in part with 

 the Abathomphalus mayaroensis Zone which marks the Upper Maestrichtian rocks 

 below the type Danian. A study of the type Maestrichtian should reveal the 

 existence of these zones in Holland. 



4. The Danian is considered to be the oldest stage of the Tertiary system, and the 

 Maestrichtian-Danian contact is taken to mark the Mesozoic-Cainozoic boundary. 



5. Comparison with previously studied Upper Cretaceous-Lower Tertiary succes- 

 sions, showed that in Egypt, this succession which was previously held to be a 

 classical example of continuous deposition between the Cretaceous and the Tertiary 

 is marked by breaks of varying magnitude. Comparison with similar successions in 

 other parts of the world showed that the Mesozoic is separated from the Cainozoic 

 in all known sections by a world-wide break, the cause of which awaits explanation. 



6. The Paleocene is considered to be a distinct series at the base of the Tertiary 

 system, older than, and equal in rank to the Eocene series. It spans the time 

 between the top of the Cretaceous and the base of the Eocene, and includes the 

 Danian as its lowest stage. The controversy over the chronological and strat- 

 graphical relationships of the various other stages and substages of the Paleocene 

 (e.g. the Montian, Thanetian, Sparnacian, Landenian, Heersian, Seelandian, etc.), 

 necessitates the temporary abandonment of these terms, and the use of planktonic 



