58 PKOCIOEDINOS OF THE JI ALACOLOGICAL SOCIETY. 



aud Gar el Gehannera. These are succeeded by the Ravine Series, 

 also of mariue character, with niollusca, fish, aud cetacean remains, 

 tbriuing the valleys of El Bats and El Wadi, which stretch eastwards 

 towards the Nile Valley, then uorthwards to Tamia, coustituting as 

 well the basal rocks of the island (Geziret el Qorn) on Birket elQurun, 

 theu extending westwards to Gar el Gehannem. Tlie third gronp is 

 the Birket el Qurun Series, with marine shells and cetacea, whicli are 

 developed in the south-eastern regions of the Fayum (Qalamsha) and 

 along its eastern sides to the northern confines of the cultivated area 

 (Tamia, etc.) ; they also form part of the rock structure of the island 

 on Birket el Qurun, as well as the Gar el Gehannem in the west. 

 These beds are followed by the Qasr el Sagha Series, containing land 

 and marine vertebrates as well as numerous shells (Carolia, etc.), 

 mostly marine, but with occasional fluviatile forms [Lanistes), the 

 whole fauna giving evidence of estuarine conditions prevailing during 

 the deposition of the beds. This series is mostly found in the 

 northern areas of the Fayum as well as at Gar el Gehannem, the best 

 development forming the cliff escarpments overlooking the Birket el 

 Qurun. 



The different ' series ' of beds here enumerated belong to the 

 ^lokattam or Parisian rocks, the lower of which, comprising the Rayan, 

 the llavine, and the Birket el Qurun, being bracketed as Lower 

 ^lokattam, while the Qasr el Sagha Series is referred to as the Upper 

 .Mokattam. Above these occur the Upper Eocene or Bartonian rocks, 

 which are developed among the escarpments of the northern part of 

 the depression to Jebel el Qatrani. The lower part of this series 

 contains quantities of silicitied woods, remains of land animals, 

 crocodiles, tortoises, etc., while the upper part shows an assemblage 

 of mollusca of marine and freshwater habits, such as Unio, Zanistes, 

 Pleurotoma, Turritella, etc., a repetition of the estuarine or fluvio- 

 marine features noticeable in the older series of the Qasr el Sagha. 

 The whole of the Bartonian is capped by the basalt, beyond the 

 boundary of which the Oligocene rocks are thought to occur, although 

 strata of that age have not been palseontologically determined as being 

 present within the actual confines of the Fayum. The Miocene 

 formation is entirely absent, although known at Mogara, some 

 100 kilometres in a north-westerly direction from the Fayum, as well 

 as at localities eastward of Cairo. Certain gravel terraces on the 

 nuith-east of the region have been referred to the Pliocene epoch, as 

 well as some sandy beds at Sidmant el Jebel and Qalamsha on the 

 south-east boundary of the depression, where the well-known Pliocene 

 ostreiform shell occurs, Alectryonia cucnllafa. The Post-Pliocene and 

 Recent deposits are fiund covering the cultivated lands and the north 

 and west of Birket el Qurun. They contain freshwater mollusca 

 comparable to forms found in tlie Nile and other African waters, 

 which include Lanistes carinatus, Olivier, sp., Viviparus nnicolor, 

 Olivier, sp., (;tc. 



The whole of the divisions may be epitomized as follows in the 

 succeeding table : — 



