IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 15 



III. STRATIGRAPHY 



A. General Discussion 



The controversy about Upper Cretaceous-Lower Tertiary stratigraphy has. 

 probably been one of the most prolonged in the history of geological literature. The 

 loose definition of the various stages and substages and their varied interpretation 

 by different authors has always made it difficult to establish the true stratigraphical 

 relationship between one stage and another, and has led to great confusion. 



A detailed study of the type sections of these stages and substages, with a critical 

 analysis of previous literature, is very badly needed to clear up this confusion. 

 However, such detail is beyond the scope of the present work, although the author 

 has sampled these sections, and the samples as well as the previous literature are 

 now being analysed. Nevertheless, it was found necessary to summarise the strati- 

 graphical problems of the various stages and substages dealt with here, and the 

 classification adopted in the present study, before proceeding to discuss the succession 

 in the Esna-Idfu region. 



The present study is mainly concerned with the period from the Upper Campanian 

 to the Lower Eocene, and the main points of disagreement about the stratigraphy of 

 this period can be summarized as follows : 



1. Where should the Campanian-Maestrichtian boundary be drawn, and what is 



the position of the Maestrichtian in Upper Cretaceous stratigraphy? 



2. Does the Danian represent the uppermost Cretaceous or the basal Tertiary, 



and what is the nature of the Mesozoic-Cainozoic boundary? 



3. What is the stratigraphical position of the Paleocene, and the relationship 



between its various stages and substages? 



4. Where should the Paleocene-Lower Eocene boundary be drawn? 



The Campanian-Maestrichtian Boundary and the position of the 

 Maestrichtian in Upper Cretaceous Stratigraphy 



In 1842, d'Orbigny introduced the term " Senonian " in Upper Cretaceous strati- 

 graphy to define the geological interval represented by the white chalk around 

 " Sens ", southeast of Paris. However, he did not designate a particular type 

 section for his Senonian, but simply stated that " Sens " is situated amidst this 

 white chalk which is characterized by its fauna. 



Four years later, Desor (1846) introduced the term " Danian " to describe the 

 succession of the Cerithium, bryozoan, coralline and coccolithic limestones which 

 disconformably overlie the Senonian white chalk of Denmark and which he had 

 previously observed at " Laversines " and " Vigny " in the Paris Basin. He 

 considered the Danian as the youngest stage of the Cretaceou system, and the same 

 concept was automatically followed by most stratigraphers. 



In 1849, Dumont introduced the term " Maestrichtian " to describe the " calcaire 

 grossier " exploited at the quarries of Maestricht 1 in southern Limbourg, Holland, 



1 Dumont's original French spelling of Maestricht is used throughout this work. 



