John Milne — Geological Notes on Cairo. 359 



to the ground, together with a few Yeins of fibrous gypsum 

 coursing upwards, is all that is observable. 



A few yards to the N.E. side of the road a cutting about 20 

 feet in depth has been made, exposing compact beds of yellowish 

 sand. Running through the face of this there are five almost 

 horizontal bands of gypsum, under one of which, and almost in 

 contact with it, is a narrow band of Oysters, which, being more 

 compact than the beds of sand, stand out to form a small 

 ledge. The largest of these bands is not more than three inches 

 in thickness. Between them, imbedded in the sand, several 

 hollow and angular shallow forms, composed of sand cemented 

 with carbonate of lime, and lined with small crystals of calcite, 

 were observable, probably pseudomorphs after Celestine. 



The base of this cutting is from 75 to 80 feet from the sum- 

 mit, and appears to be the lowest exposure of the Red Beds. 



From this point there is a descent of about 50 feet down 

 a bank of earth-sand, covered with fragments of gypsum, the 

 result of the disintegration carried on up above to the Lime- 

 stones or White Beds in which the quarries are. 



From these notes it would appear that the characteristic 

 feature of these upper or Brown Beds is the number of bands 

 made up of fossil Ostrece. At a short distance in many places 

 these appear like a shale, and it is not until a close inspection 

 is made that their real nature can be seen, which in some cases 

 bears a sti'iking resemblance to the beds of Ostrea distorta in 

 our Purbeck series. 



Imbedded with them are other shells, which may be easily 

 detached ; but the Oysters themselves are so matted and friable 

 that it is difficult to obtain single specimens. 



IL— White Beds. 

 F. These commence 125 feet from the summit of the hill, and 

 lithologically are very similar down to the lowest point yet 

 excavated, 225 feet still lower, the lower beds differing from 

 those above them in perhaps being more compact and of a fine 

 texture. In places the rock is visibly almost wholly made up 

 of fossil remains, these being more apparent in the upper than in 

 the lower beds. 

 7. — At 160 feet from the summit on the north side of the road 

 there is a concretionary band of limestone, the nodules of which 

 are discoidal, about the size of a potato, but not noticeably 

 elongated. 



On this level, which is that of the road marked C on Plan, 

 Fig. 3, numbers of minute Nummulites are visible, together 

 with species of Echini. This is also an horizon of the beds con- 

 taining Celestine, specimens of which may be seen in radial 

 forms imbedded in the white limestone. When they fill the 

 chambers of some fossil, as a Nautilus, perfect, well-defined, 

 and brilliant faces of crystals are to be seen, — the various forms 

 and combinations of which are described in the paper already 

 referred to by Messrs. Bauerman and Foster (ante p. 353). 



