40 Mr Nash on the Geology of Egypt. 



At Brandon I was told that, in the present depressed state of 

 the trade, arising from the use of percussion caps, the best mus- 

 ket-flints were sold from 7s. to 8s. a thousand, which at one 

 time, during the war, were sold for two guineas. 



On the Geology of Egypt and the Valley ofCosseir. By D. W. 

 NASH, Esq. A. L. S., Assistant Surgeon, Bengal Army. 

 Communicated by the Author. 



EGYPT, or that portion of the valley of the Nile north of the 

 first cataract, is bounded on the north by the Mediterranean, on 

 the south by Nubia, and on the east and west by two ranges of 

 mountains which run in lines nearly parallel to each other from 

 the first cataract to Cairo, leaving between them a valley of 

 variable width from three to nine miles broad, and separated by 

 these mountain ridges on the eastern side from the Red Sea, and 

 on the western from the great Lybian desert. In this valley 

 flows the river Nile, now hemmed in and confined to a narrow bed 

 by the rocks which close in upon it on either side ; now gliding 

 through the rich alluvial plain of which it is the fertile parent. 



Geologically, Egypt may be formed into four great districts, 

 according to the nature of the formations presented to us in our 

 course down the Nile, from the first cataract or Assouan to the 

 shores of the Mediterranean. These are the granite, the sand- 

 stone, the limestone, and the alluvial formations. The granite 

 formation extends from the mountains of Nubia to Assouan in 

 24 north latitude, where the river rushes rapidly through the 

 granite rocks which impede its course, and form what is called 

 the first cataract. These cataracts, five or six in number, occur 

 throughout the* whole course of the Nile southward of Assouan, 

 as far as Cartoon, where the two branches of the river unite ; 

 the branch called the Bahr ul Neel or Blue River (a term which 

 is also applied by the Arabs to the Nile in its entire course from 

 Cartoon to Cairo), coming from the Lake Dembea in Abyssinia ; 

 and the Bahr ul Abiad or White River, coming from the south- 

 tfest through unexplored regions inhabited by savage tribes, and 

 supposed by many to flow past the walls of the mysterious city 

 of Timbuctoo. 



