Vol. 67.] DURING THE CRETACEOUS AND EOCENE PERIODS. 135 



series of strata 65 metres thick, rich in Sismondia logotheti Fraas, 

 Turritella cegyptiaca M.-E., T. oocycrepis M.-E., and Callianassa 

 nilotica. These strata are of wide extension, for M. Fourtau has 

 recognized Sismondia logoiheti and Callianassa nilotica, associated 

 with an ovoid Echinolampas (named by him E. humei), in the 

 collections made by me on the road from Dungul to Nakheil, a 

 position in the Western Desert about the latitude of Aswan. North- 

 east of the Baharia Oasis these beds re-appear with the ovoid forms 

 oi Ecliinolampas, but the typical Callianassa nilotica and Sismondia 

 logotheti have not been recognized. 



With regard to the broader geographical relationships during the 

 Libyan Epoch, much study of detail is required ; but, in a recent 

 paper, M. Fourtau l has pointed out some features of great interest, 

 in connexion with the distribution of the sea-urchins obtained at 

 Minia, the Rhabdocidaris navillei Cott. being a typical Indian 

 form from Hyderabad, as is also Dictyopleurus haimei Duncan & 

 Sladen. He adduces reasons for believing that the Egyptian portion 

 of the Eocene sea formed a centre of acclimatization of the Indo- 

 Pacific species in their migration to the west, there being no 

 affinities of this nature either with the Tunisian and Algerian 

 fauna, or with the Northern Mediterranean basin, whether in 

 Spain, France, or the Vicentino. He especially calls attention to 

 the great affinity of this Upper Libyan fauna with that of the 

 Eocene ' Kirthar Series' in India, citing as examples the close 

 resemblance of certain species of Conoclypeus from Kirthar to 

 C. delanouei ; the Sismondia varians is almost a mutation of 

 JS. polymorpha ; and among the Cassidulidge, which are abundant 

 in both regions, the genus Qisopygus has numerous representatives 

 closely related to Indian forms of this genus. The genus Kephrenia 

 appears to be descended from the Indian Paralampas, both being 

 possibly derived from Pygurostoma of the Upper Cretaceous in 

 Persia. These Indian affinities are, of course, of much interest and 

 point out directions of further study ; but the correspondence cannot 

 be pressed too far, as from my collections in the extreme west 

 of Egypt, near Baharia Oasis, M. Fourtau has identified the 

 presence of the genus Pseudopygaulus, which iudicates Algerian 

 rather than Indian influence. 



The Lower Eocene strata, as a whole, appear to be remarkably 

 uniform in structure and palaeontological character over the greater 

 part of Western Egypt ; while in Eastern Egypt the presence 

 of the ' remade ' white limestoues introduces a problem of a very 

 complex, if interesting character. 



In the next division to be considered, the Middle Eocene, local 

 variations are presented which suggest the differentiation of 

 important land-masses in the western and southern portions of 

 Egypt. 



1 ' Echinides de Minieh ' Bull. Inst. Egypt, ser. 5, vol. ii (1908) p. 183. 



