Dr. John Ball—The Nile Valley and Gulf of Sues. ual 
TV.—On tur Ornrern or tHE Nine VALLEY AND THE Gutr oF Surz.! 
By Joun Barz, Ph.D., D.Se., F.G.S. . 
ia Captain Lyons’ Physiography of the River Nile and its Basin 
(Cairo, 1906, p. 294), there occurs the following statement :— 
‘¢TIn a trough from 2 to 10 kilometres wide and 100 to 300 metres 
deep lies the Nile, meandering through a flood plain formed by yearly 
deposits of silt brought down from the Abyssinian table-land by the 
Blue Nile and the Atbara. This trough was determined in the first 
instance by fractures of the crust which caused a strip of country from 
about Edfu (lat. 25° N.) to Cairo to be depressed, leaving the plateau 
standing high above it, just as the Red Sea and the gulfs of Suez and 
Akaba were formed, probably about the same epoch. This interference 
with the drainage of the country doubtless produced a series of lakes 
in the low-lying area, while the drainage of the eastern plateau com- 
menced to excavate the valleys which now exist as dry desert wadies, 
their development being in many cases far from complete, as shown by 
the cliffs which interrupt the slope of the valley when a harder bed 
of rock than usual is met with. 
‘‘ Into this depressed area the drainage ot the southern part of the 
basin finally flowed, and there laid down the alluvial deposit through 
which the river flows to-day.” 
A clear and definite pronouncement of this kind, coming from so 
high an authority as the former Director-General of the Geological 
Survey of Egypt, is likely to convey the impression that the ‘ nft 
theory ’ of the origin of the Nile Valley and Gulf of Suez is supported 
by evidence which leaves no room for any other view. This is very 
far from being the case. ‘To my mind the field-evidences are entirely 
against the ‘rift theory ’; they point rather to the Nile Valley being 
essentially a valley of erosion (though faults or lines of weakness may 
have had something to do in influencing the river’s course), and to the 
Gulf of Suez being an eroded anticline. 
During my twelve years of survey work in Egypt, most of which 
has been spent in geologizing, I have felt myself becoming increasingly 
sceptical as to the truth of the ‘ rift theory’ of the orgin of the Nile 
Valley and the Gulf of Suez. But it was not till the spring of the 
present year, when I examined the geological structure of the Wadi 
Araba and part of the Gulf of Suez, that I obtained evidence which 
appears to be absolutely convincing against the ‘rift’ view cited above. 
The Wadi Araba is a great valley some 20 miles wide, draining 
north-eastwards into the Gulf of Suez between latitudes 29° 3’ and 
29° 22’N. It divides two great plateaux, the North and South 
Galala Mountains, which rise to heights of over 4000 feet. . The faces 
of the plateaux which shut in the valley are steep cliffs, in which are 
exposed a great thickness of Eocene limestones, overlying Cretaceous 
limestones, marls, and clays, with Nubian Sandstone at the base. The 
beds, especially the lower ones, havea well-marked dip into the scarp, 
showing the valley to be an eroded. anticline; and this structure is 
confirmed by the fact that as one crosses the valley, deeper and deeper 
1 By permission of the Director-General, Survey Department. 
