Vol. 67.] DUKING THE CKETACEOUS AND EOCENE PERIODS. 125 



different is the fauna of the Danian in the Western Oases, where 

 Zittel recognized three well-marked divisions : — 



(a) Snow-white well-bedded limestones or earthy chalk. 



(b) Greenish and ash en-grey paper-shales. 



(c) Beds with Exogyra overwegi Buch. 



These beds are characterized by a fauna consisting of small 

 gasteropoda, bivalves, corals, crinoids, etc., replaced in iron oxide, 

 which have been made familiar to all students of this subject in 

 the works of Quaas and Wanner, based on Zittel's collected materials. 

 The side-issue as to the age of the Pecten Beds had been settled 

 by Dr. Blanckenhorn's recognition of the Pecten (named P. mayer- 

 eymari by Mr. R. Bullen Newton) as being identical with the P. 

 farafrensis of Zittel, but certain difficulties still existed in 

 regard to their correlation with the Danian beds of Western Egypt.. 

 Delanoue l had obtained a rich fauna in the grey paper-shales 

 31 metres thick, which underlie the Eocene limestone at Thebes, 

 foraminifera and ostracods being abundant ; while, among the larger 

 forms, d'Archiac recognized numerous gasteropoda (Fusus, Triton, 

 Cerithium, Natica), cephalopoda (Aturia ziczac Sow., Nautilus 

 centralis Sow,, and N. delanouei d'Archiac), dimyarian bivalves- 

 (Nucula. Leda, Lucina, Neozra), and brachiopoda such as Terebratu- 

 lina tenuistriata (Leym.). This assemblage, regarded as recalling^ 

 the fauna of the London Clay, led to the inclusion of the shales in 

 the Eocene. 



During his visit to Egypt, Zittel extended his researches to the- 

 eastern side of the Nile, and called attention to the importance of a 

 layer rich in Cretaceous oysters conspicuously deveJoped near Edfu. 

 These he regarded as the equivalent of his Exogyra Beds in Kharga 

 Oasis, etc., and remarked that, if this were the case, between it and 

 the Lower Eocene should be a thick complex of ashen-grey or green 

 paper-shales, and above these a white chalky limestone. 



The shales were noted by him on the right shore of the Nile near 

 Esna, where they underlay the snow-white Lower Eocene Operculina 

 Limestone, Dr. Schweinfurth also noting them at the base of the 

 Eocene escarpment on both Nile banks. Zittel remarked, however,, 

 that neither he nor Dr. Schweinfurth had been successful in finding 

 fossils in them, adding : 



1 If these paper-shales of Esneh correspond with those of Khargeb and 

 Dakhel, then the uppermost white Cretaceous limestone with Ananchytes. 

 ovata is either wanting at Esneh, or does not contain any fossils and cannot 

 thus be distinguished from the petrographically similar Eocene limestone of 

 the Libyan stage/ 



the latter alternative being considered the more probable. 2 



1 C. B. Acad. Sci. Paris, vol. lxvii (1868) pp. 704-707. 



2 ' Beitrage zur Geologie & Palaontologie der Libyschen Wiiste ' Palaeon- 

 tographica, vol. xxx, pt. i (1883) p. lxxviii. Dr. G. Schweinfurth, in Peter- 

 mann's Mitteilungen, vol. xlvii (1901) p. 6, regarded the paper-shales at Esna 

 and Sharawna as of Eocene age, following the opinion then held by most 

 writers. See also K. Eourtau, Bull. Soc. Geol. France, eer. 3, vol. xxvii (1899) 

 p. 481. 



