IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 29 



To overcome the difficulty of correlating marine and non-marine deposits and the 

 uncertainty resulting from such correlation, Hottinger & Schaub (i960) proposed the 

 Ilerdian as a new stage to represent the marine Upper Paleocene. These authors 

 studied the larger Foraminifera of this new stage and stated that it has no equivalent 

 in the Paris Basin, but added " We only know that it is immediately below the 

 Cuisian. Very likely it lies between the Cuisian and the marine phase of the Montian. 

 So far we had no opportunity to determine whether a part — and in the affirmative 

 case, which part — of this stage corresponds with the marine phase of the Landenian." 



Gartner & Hay (1962) studied the planktonic Foraminifera of the type Ilerdian, 

 and affirmed its Upper Paleocene age. However, examination of several Ilerdian 

 samples from Mont Cayla, kindly presented by Miss M. Toumarkine of the Sorbonne, 

 has shown that these deposits are of Lower Eocene, rather than of Paleocene age 

 (see discussion under each of the species recorded by Gartner & Hay 1962). This 

 throws doubt on Hottinger & Schaub's conclusion, on Gartner & Hay's identifications 

 and on the validity of the Ilerdian as a stage of the Paleocene. The use of the term 

 Ilerdian in Paleocene stratigraphy is therefore considered inadvisable, especially 

 as the relationship of the " Ilerdian " to the other stages and substages of the 

 Paleocene is not yet understood. [The type section of the Ilerdian in the Tremp 

 basin, as well as several other Ilerdian outcrops in Spain and in France, have been 

 sampled in detail by the present author in an attempt to discover their true strati- 

 graphical positions.] 



In the present study, 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 about the chronological and 

 stratigraphical relationships of the various stages and substages of the Paleocene 

 (other than the Danian) as summarized above, necessitates the temporary abandon- 

 ment of these terms and the use of faunal zones instead. The establishment of 

 faunal zones which are built on the basis of evident evolutionary trends, and which 

 can be correlated in various parts of the world, is the only solution at the moment to 

 the numerous problems in Paleocene stratigraphy. Correlation of the type sections 

 of the various stages and substages of the Paleocene with these zones is bound to 

 show the true stratigraphical relationship between one stage and the other, and will 

 lead to the development of a reliable means of correlation for this series. 2 



The present study has shown that in Egypt and elsewhere, the Paleocene is 

 divisible into three faunal zones in which the planktonic Foraminifera represent 

 a continuous evolutionary sequence showing clearly recognizable trends. Each of 

 these zones corresponds to a definite evolutionary stage. They are as follows : 



1. A lower zone marked by the first appearance at its base of the genera Globoro- 

 talia and Globigerina, and characterized by an assemblage of Globigerina and globi- 



2 The relationship between these stages has now been clarified and the suggested stage names are 

 discussed elsewhere (El-Naggar, in press), and inserted on some of the accompanying figures. 



