The physical features in the neighbourhood of Assuan were 

 then described and illustrated, and afterwards the journey down 

 the Nile was continued. It was pointed out that the Nubian sand- 

 stone disappears from view owing to a very gentle northerly dip ; 

 that, at Luxor, the western side of the valley is bounded by the 

 edge of the Libyan desert, formed by Eocene limestone; and that 

 water eroded valleys descend from the level of the plateau. Views 

 in two of these valleys were shown and attention was called to 

 the fact thai their lower portions have been excavated in the 

 debris brought down by rainstorms from the high ground on the 

 west. In dealing with the physical features of the Nile valley 

 "between Luxor and Cairo, the President called attention to the 

 remarkable regularity of the stratification. 



To a British geologist, accustomed to deal with folded and 

 faulted rocks and with rapid changes in lilhological character, 

 this is a feature which most impresses him in a journey down the 

 Nile. He looks for faults in the cliffs and sees none. The only 

 disturbances that he sees appear to be slips down the steep faces. 

 For hundreds of miles the stratification is parallel, so far as the 

 eye can tell, with that of the Nile alluvium and with the surface of 

 the water on which he is sailing. Nevertheless, the average 

 slope of the valley is slightly less than that of the rocks so that he 

 is asce n ding in the stratigraphical sequence. Occasionally the 

 line of cliffs is broken where a lateral valley debouches from the 

 desert plateau. Such a plateau is usually dry ; but at intervals, it 

 may be of six or seven years, owing to the cloudbursts on the 

 Red Sea Hills, it carries down to the river a raging torrent of 

 water, mud and stones of various sizes. 



Having traced the course of the Nile from the second Cata- 

 ract to Cairo, he then described the structure of the Libyan desert 

 plateau, and of the Kharga oasis, illustrating his remarks by 

 photographs of the desert, of sand dunes and of the effects of 

 wind erosion. 



Referring to the Miocene rocks of Northern Egypt, he briefly 

 summarised the results embodied in a recent " Report on the Oil- 

 fields Region of Egypt " by Dr. Hume, the director of the 

 Egyptian Geological Survey. "These Miocene rocks," he said, 

 **■ are of great interest both from a scientific and from an econo- 

 mic point of view. In the Gulf of Suez region they present us 

 with a type of structure wholly different from that which prevails 

 in the great desert plateaux of North Africa and Arabia ; and 

 borings through them have yielded considerable quantities of oil 

 at Jemsa, near the entrance to the gulf, and more recently at Rar- 

 quada, about 30 miles further south, near the shores of the Red 

 Sea. They consist not only of sediments formed in the open sea, 

 Out also of a great thickness of salt and gypsum. It seems clear 

 that both as regards a°e and mode of formation they are more or 

 less allied to those of the Carpathian salt beds; and probably also 

 to the similar beds of Armenia, the Iran an tableland, the va 1 ley 



