64 F. Chapman — Foraminiferal Limestones from Egypt. 



Box G, No. 1,467(^. " Nummulites from a locality 39 kilometres 



west of Bawitti, on plateau west of Baharia Oasis " (H. J. L. 



Beadnell).! 



A collection of nummulites of one kind, namely, N. Gizeliensis 



var. Paclioi ; these specimens are greatly worn and sand-polished. 



Also a small fragment of limestone crowded with specimens of 



N. curvispira. 



Eocene : Upper Libyan or Lower Mokattam Series. 



Box M, No. l,4:80e. " Operculince and nummulites, 39 kilometres 

 west of Bawitti, on plateau west of Baharia Oasis " (H. J. L. 

 Beadnell). (PI. IV, Fig. 4.) 



The micro-structural features of this limestone are rather 

 peculiar. Apparently the interstitial mud has crystallized round the 

 nummulites, and during this process the cement has contracted so 

 as to leave interspaces in the rook. The resultant cavities have 

 subsequently been partially or entirely filled with little geodes of 

 secondary quartz, showing a polysynthetic type of structure under 

 polarized light with the microscope. This condition of the limestone 

 seems to render it almost proof against weathering action. The 

 rock is rather variable in its colour and appearance, and presents 

 a pale cream to a dark reddish tint, due to the varying amounts 

 of iron-staining. The surfaces of some of the rock-specimens are 

 wind-polished. In mineralogical structure some of the samples have 

 almost passed into the condition of Beekite. 



The following foraminifera occur in this rock : Textularia ? gramen, 

 Glohigerina buUoides, Operculina complanata var. discoidea, Nummulites 

 Gizeliensis var. Pachoi, JV. curvispira, JV. discorbina, N. suhdiscorhina, 

 and Orhitoides (Discocyclina) dispansa ( = 0. dilabida, Sch wager). 



Eocene : Upper Libyan or Lower Mokattam Series. 



Box M, Nos. 3,335& and c. " AlveoUna-lim.eBtone, western wall 

 of depression of Farafra Oasis (El-Guss- Abu-Said)" (H. J. L. 

 Beadnell). (PI. IV, Fig. 5.) 



A white or pale cream-coloured limestone, having a soft crumbling 

 texture, and crowded with Alveolince. The fractured surface of the 

 rock is seen to be thickly studded with these foraminifera, or shows 

 numerous cavities where they have dropped out. A rudely stratified 

 structure is seen in weathered surfaces of this limestone, or where 

 it has been subjected to wind- wearing action. 



The groundmass of this rock seen under the microscope is finely 

 granular, but crystalline ; and the interior of the organisms are 

 usually filled with calcite crystals, larger than those of the cement, 

 a result of slower growth. 



Four species of Ostracoda were found in the disintegrated rock, 

 viz., Bairdia suhdeltoidea, B. Beadnelli sp, nov,, B. minuta sp. nov., 

 and CytJiere farafrensis sp. nov. 



1 In his paper on ' ' Eecent Geological Discoveries in the Nile Valley and Libyan 

 Desert" (London, 1901), Mr. Beadnell refers in detail to the relations of the 

 Cretaceous and Eocene at the above-named locality, and regards the nummiilitic and 

 Operculina limestones as Upper Libyan (p. 12 op. cit.). 



