IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 263 



(29). Globotruncana cretacea Cushman (p. 387, pi. 3, fig. 4) is probably a deformed 

 specimen of Globotruncana stuarti stuarti (de Lapparent). It is described as being 

 biconvex and single-keeled while Cushman's form, as re-examined by Bronnimann & 

 Brown (1956), has two keels in all chambers of the last whorl. 



(30). Globotruncana gansseri Bolli (p. 387, pi. 3, fig. 3) is a doubtful form. It is 

 described as having a distinct and keeled umbilical shoulder and an aperture with 

 perforate tegilla. It is not really known what is meant by keeled umbilical shoulder 

 or perforate tegilla as the latter are always imperforate. Again, while they described 

 the chamber number as 5-6 in the last whorl, their figured specimen shows only 3J 

 chambers. 



(31). Globotruncana rosetta (Carsey) (p. 387, pi. 3, fig. 5) is shown to have an 

 entirely single keel while the holotype is characterized by two closely spaced keels 

 on the early part of the last whorl (see Bronnimann & Brown 1956). 



(32). Globotruncana stuarti (de Lapparent) (p. 387, pi. 2, fig. 3) belongs to Globo- 

 truncana conica White. 



(33)- Globigerina daubjergensis Bronnimann (p. 387, pi. 3, fig. 8) does not belong 

 to this species. It is much larger, less raised on the dorsal side and has fewer 

 chambers in the last whorl which increase more rapidly than in the typical form. It 

 is probably Globigerina triloculinoides Plummer. 



(34). Globigerina inaequispira Subbotina (p. 387, pi. 3, fig. 10) is a doubtful form 

 which differs markedly from the holotype. 



(35)- Globigerina pseudobtdloides Plummer (p. 388, no figs.) is a very confusing 

 record as the authors also recorded what they describe as Globorotalia pseudobulloides 

 (Plummer) in the same study. 



(36). Globigerina quadrata White (p. 388, pi. 3, fig. 22) is clearly shown in their 

 figure to have an extraumbilical aperture although included by them in the genus 

 Globigerina. 



C. Concerning their lithostratigraphical zonation. 



Following Ghorab (1956) and Said (1961, 1962) they have used the term Dakhla 

 shale as a substitute for the older term Lower Esna shale. The Dakhla shale, as 

 originally designated, includes the Maestrichtian Sharawna shale, the conglomerate 

 separating it from the overlying Paleocene Owaina shale, and the lower part of the 

 latter formation. These varied, lithological and palaeontological units, which are 

 clearly separated by a marked break, cannot be treated as one formation. Thus, 

 the term Dakhla shale is here dropped and the classification of the Esna group into a 

 Lower Sharawna formation and an Upper Owaina formation is here suggested. 



They have treated the chalk separately and restricted the Esna shale to the succes- 

 sion of strata between the chalk and the base of the Thebes formation which is here 

 assigned to the Upper Owaina shale member. However, this restricted use of the 

 term is contrary to the original usage and conflicts with the lithological relationships 

 of the various units in the field as well as with their palaeontological continuity. 



