360 JoTin Milne — Geological Notes on Cairo. 



G.8. — Lying along the line of the second road, in Plan marked B, are 



many blocks that have fallen from above, and are seen to be 



full of Celestine. Here the rock is more compact than above, 



and the fossil remains are not so distinct, with the exception of 



certain Crustacea, which are remarkably well defined, the species 



Lobocarcinus PauUno-Wwtemburgensis being very common. 



In the face of this scarp there is a noticeable yellow band, 



containing Oysters and Nummulites. 



H.9. — The line of the lower road, marked A upon Plan, leads into 



the lowest part of the quarry, 350 feet from the summit. 



Celestine is also found here ; but it apparently differs from that 



found above in being massive, one piece showing an exposed 



surface 1 ft. 9 in. wide, perfectly transparent, and of a light 



yellow colour, — no transparent colourless crystals or opaque 



bluish white stellar forms, like those described by Bauerman 



and Foster, being found. 



About 12 feet up the face of this scarp there is a bed exceedingly 



full of Nummulites, corals, and other fossil-remains, together with 



some remarkably well-preserved casts of a spiral shell, probably a 



a species of Turbo. 



In travelling towards the north, in the direction of the Tombs of 

 the Caliphs, owing to the dip of the beds in this direction, newer 

 beds, corresponding to the second and third scarps of the Citadel 

 Quarries, are met with, sections of which may be observed in the 

 many valleys entering from the N.E. 



Immediately outside the quarry in this direction numerous shark's 

 teeth are met^ with, which are followed by large Nautili and other 

 fossils. In the quarries behind the Tombs of the Caliphs Crus- 

 tacea and casts of Turbo are again met with in abundance, beyond 

 which, on crossing a small valley, you come to Jebel Achmar, or the 

 Ked Mountain. 



Jebel Achmar. — This mountain or chain of hills is about 225 feet 

 above Cairo. At a distance they appear to be very red ; but on 

 nearing them this is seen to be partially superficial, the exterior 

 colour being due to an oxidation through exposure of the iron con- 

 tained in the rock, which is a moderately fine-grained yellowish 

 quartzose sandstone. 



The texture, however, varies, portions having quite a conglome- 

 ratic aspect, — white quartz pebbles about a quarter of an inch in 

 diameter being inclosed in a red base. 



The fine parts of the rock are quarried for grindstones and mill- 

 stones, which are manufactured in Cairo. 



Petrified Forest. — This interesting deposit of silicified wood having 

 been already described by Mr. W. Carruthers, F.E.S. (GtEOL. Mag. 

 1870, Vol. VII. p. 306), it will be well not to run over old ground, 

 but rather to describe the road leading to the so-called " Forest," 

 than to speak of the Forest itself. 



Leaving the Eed Hills upon the left, the track towards this Forest 

 enters the second valley counted in the direction of the Citadel, 

 crossing the entrance to which, and also running up it for a short 

 distance, is a tramway for fetching stone. 



