Mr Nash on the Geology of Egypt. 47 



character, argillaceous, soft, and friable ; abounding, compara- 

 tively, in springs of water, which have all a more or less saline im- 

 pregnation, and situated immediately beneath a secondary lime- 

 stone. It forms, for the most part, rounded hillsofnogreat elevation, 

 with sloping sides, cut into ravines by numerous watercourses in 

 the Cosseir district, and having their bases covered by hillocks of 

 their accumulated debris. Throughout the Valley of Cosseir, 

 the principal wells are in this sandstone. The limestone forma- 

 tion, which lies directly on the sandstone, is in general of a 

 greyish-white colour, has a conchoidal or splintery fracture, and 

 contains, in the Valley of Cosseir, large quantities of siliceous 

 fossils, of which the principal are, ostrea, cardia, madrepores, 

 and sponges. 



That part of the limestone formation which is near Cairo, and 

 is called the Mokattam, contains an abundance of nummulites. 

 In the Valley of Cosseir, I found a turritella and considerable 

 quantities of gypsum. At Siout, and thence to Kenneh and 

 Esneh, where the sandstone commences, the limestone is of the 

 same kind, but there are no nummulites, and it contains vast 

 quantities of rounded flints. Professor Ehrenberg states, that 

 there is dolomitic limestone on the western shore of the Gulf of 

 Suez, and calls the limestone above Siout, which is destitute of 

 nummulites, Jura limestone without fossils ; it is, however, full 

 of flints. 



Both the limestone and the sandstone are secondary forma- 

 tions ; the latter appears to be the same as the new red, or 

 saliniferous sandstone, and the former may perhaps be equiva- 

 lent to the cretaceous group ; but without a more extended 

 knowledge of their organic remains, it is impossible to form a 

 decided opinion. 



Some Observations on the Geography and Geology of Northern 

 and Central Turkey. By Dr A. BOUE'. Communicated 

 by the Author, in a letter to the Editor.* 



DEAR SIB, I take the liberty of sending you the chief re- 

 sult of my first excursion through Turkey, a country to the in- 



* Less is knownj of the physical geography and geology of Northern and 



