36 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



correlating these six widely spaced sections, Nakkady (1951a, chart) showed the 

 existence of great differences in the thickness and the stratigraphical position of his 

 Buffer zone, and in the position of the upper limit of his Maestrichtian Globotruncana 

 Zone in the different sections studied. However, no attempt was made to explain 

 this marked variation, and instead of interpreting it in the obvious way, as a marked 

 stratigraphical break, Nakkady emphasized the conformity of the succession and 

 stated (1951a) that " The chalk and the overlying Esna shales are two phases of 

 continuous sedimentation representing the last sequence of deposition at the close 

 of the Mesozoic and the advent of the Tertiary ". Moreover, he described the Esna 

 shale fauna as transitional in character, and thus followed Beadnell (1905) in regard- 

 ing the Esna shales as passage beds between the Cretaceous and the Eocene. Further- 

 more, despite the discovery of breaks between the Cretaceous and the Tertiary in 

 successions previously described as conformable throughout (e.g. Le Roy 1953), 

 Nakkady did not reconsider his statements. On the contrary, this author (1957, 

 1959) on one side, and Said & Kenawy (1956) and Said (i960) on the other, started a 

 lengthy argument on the so-called retardation in the appearance of Globorotalia 

 species in the various sections studied, and its different implications, but overlooked 

 the fact that this can be explained by the occurrence of breaks of varying magnitude 

 between the Cretaceous and the overlying Tertiary rocks. 



Le Roy (1953) described the Upper Cretaceous-Lower Tertiary succession of the 

 Maqfi section, on the northeastern corner of the Farafra Oasis, Western Desert, 

 Egypt, and analysed its small foraminiferal fauna. He did not discuss the Nubia 

 variegated claystones and sandstones which constitute the basal part of the succes- 

 sion, but stated that they may probably be of pre-Maestrichtian age and may be 

 separated from the overlying chalk by an unconformity, interpreted by the abrupt 

 change in lithology between the two formations. Nevertheless, he recognized in the 

 overlying succession two major divisions demarcated by a minor lithological change 

 and a major palaeontological hiatus, a lower chalk unit of Upper Cretaceous (Mae- 

 strichtian) age, which he termed " Unit A " and an overlying succession of four rock 

 units (IV, III, II and I) of Lower Tertiary age. He recorded the abrupt faunal 

 change between " Unit A " and " Unit IV " which he interpreted as a probable 

 disconformity and stated that it could logically indicate the Mesozoic-Cainozoic 

 boundary. 



Le Roy stressed the difficulty in assigning the Tertiary part of the succession to the 

 Paleocene or the Lower Eocene, and stated that " Until the Egyptian Paleocene is 

 more specifically correlated in terms of the European section, the writer favours 

 allocating Unit IV to the basal Eocene ". However, comparison with the present 

 study proves this " Unit IV " to be of Upper Paleocene age, and substantiates a 

 marked break between the Maestrichtian and the overlying Upper Paleocene. On 

 the other hand, Le Roy recorded a distinct erosional surface between his " Unit IV ' 

 and the overlying " Unit III ", and a probable disconformity between the latter and 

 " Unit II ". This drove Nakkady (1957) to interpret " Unit III " as a slipped 

 mass of the nummulitic limestone capping the succession. However, Le Roy 



