NEWTON : LOWER XEUTIAKT 5I0LLUSCA OF THE FAYUM. 65 



Returning to the consideration of the age of the Jebel el Qatraui 

 Series of vertebrates, it is almost possible that, instead of regarding 

 them as younger than Bartouian, as has been suggested, the field 

 evidence might even favour an older period for their deposition. This 

 suggestion would arise out of the fact that there is only a distance of 

 a few metres between the base of the Jebel el Qatrani Series and Bed 

 No. 2 of the Qasr el Sagha section, containing the youngest of the 

 vertebrate remains of that series, and only some 70 metres below to 

 Beds iS'os. 16 and 17 where the chief of the vertebrates are foimd. In 

 any case, a generic resemblance has been observed in the two sets of 

 beds, and it is interesting to note that Mwrithermm and Stereogenys 

 occur alike in the Qasr el Sagha and the Jebel el Qatrani Series. 



The Jebel el Qatrani mollusca now in the Egyptian Geological 

 Survev Museum at Cairo consist of the following species, the ' Beds ' 

 referred to being those described by Mr. Beadnell, while the asterisks 

 mark iJr. Blanckenhorn's published determinations. 



Gasteofoda. 



^Lanistes Bartoniamis, Blanckenhorn (Bed No. 15). 



*Poiamides scalaroides, Deshayes (Bed No. 7). 



*Pofamides tn'stn'atus, Ltimarck (Bed No. 7). 



'^Jfc'Iania, n.sp., Blanckenhorn [related to M. jSfysti] (Bed No. 7). 



^Cerithium tiarella, Deshayes (Bed No. 7). 



Pleurotoma ingens, Mayer-Eymar (Beii No. 7). 



Tarritella transitoria, Mayer-Eymar [related to T. angulata, J. dc C. 

 Sowerby] (Bed No. 7). 



Pelecypoda. 



LitJiophagus allied to cordatus, Lamarck. 



Area, Lueina, Tellina, *TJnio, ^Mutela, '^Spatha (all these forms are 

 probably from Bed No. 15). 



The specimens mostly comprised hard calcareous sandstone casts, the 

 smaller Gastropods being represented by hollow cavities, impressions 

 of which were taken in wax so as to obtain a reproduction of the sliell 

 and its sculpture. In this way there is still preserved among the 

 Egyptian fossils at the British Museum (Natural History) reproductions 

 in wax of the two more important freshwater species, Potamides 

 scalaroides and tristriatus. These I liave quite recently re-examined; 

 and I am still convinced that the original determinations are correct, 

 and that in those species we have a fragment of a fauna wliich 

 can only be synchronized with the ' Beauchamp Sands ' of Paris, as 

 demonstrated in Dr. Blanckenhorn's published paper of 1900: 



According to the latest work on the geology of the Paris Basin, 

 M. Lemoine ' regards the 'Beauchamp Sands' as belonging to the 

 Ermenouvillien stage of the Bartouian, which is quite the lower 

 or older portion of that group of rocks, and consequently far removed 

 from either the Ludian or Sannoisian-Stampian horizon, which some 

 authorities have acknowledged as the more accurate age for the shells 



^ Geologie du Bassin de Paris, 1911, pp. 239-47. 



