40 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 5, 



variability of the middle cretaceous Echiuodermata made in my for- 

 mer communication. 



Note. — The Eev. H. Holland informs me that in the Wady Ba- 

 dera the Echiuodermata occurred in the bed of the Wady, having 

 evidently been washed down from a bed of limestone which exists 

 near the pass at its head. This pass is composed of variegated 

 sandstone rocks resting upon gneiss. The sandstone occurs at a 

 higher elevation than the limestone ; but the exact position of the 

 latter I did not remark. The Echinoderms from Wady Mokatteb 

 were found in a small bed of limestone at the foot of Jebel Mokat- 

 teb, which crops out beneath a sandstone. 



2. Geological Description of the Eirst Cataract, Upper Egypt. 

 By J. C. Hawkshaw, Esq., E.G.S. 



[The publication of this paper is unavoidably deferred.] 

 (Abstract.) 

 At the Eirst Cataract the Nile flows over crystalline rocks consisting 

 principally of quartz, felspar, and hornblende, combined in various 

 proportions, and then appearing under the forms of syenite, green- 

 stone, hornblende, and mica-schists, or else occurring in separate 

 masses. In the bed of the river the surface of the harder portions 

 of these rocks is beautifully polished. The whole district is tra- 

 versed by dykes of greenstone, of which the prevailing direction is 

 E. and AY. 



The cr\^stalline rocks forming the bed of the river are overlain by 

 a sandstone, sometimes coarse and gritty, and at other times fine- 

 grained and compact. The prevailing colour is light yellow ; but in 

 places it is dark-purple and even black, owing to the presence of 

 iron. As yet no organic remains have been discovered in it. This 

 sandstone rests on the uneven surface of the syenite, in slightly 

 inclined strata dipping N.N.E. It is nowhere altered at its junc- 

 tion with the syenite, nor is it anywhere penetrated by dykes. 



To the eastward of the Eirst Cataract is a wide vaUey, commencing 

 opposite the Island of Philee, and joining the Nile valley again about 

 three miles below Assouan. Through this vaUey the Nile may have 

 formerly flowed, as freshwater shells and deposits of Nile-mud are 

 found at a considerable height above the present level of the river. 



To the westward of the Eirst Cataract the crystalline rocks dis- 

 appear below the sandstone, and the country is almost entirely 

 covered with sand of a rich yellow colour, composed of fine rounded 

 grains of quartz. 



3. On the Dript of the North of England. By J. Curry, Esq. 



(Communicated by the Assistant-Secretary.) 



[Abstract.] 



The Drift under consideration is stated to occupy certain slopes 



from the following mountain-eminences, namely : — Skiddaw, Saddle- 



