4 Dr. John Ball— The Gulf of Suez. 



of, any known area of trough-subsidence other than the Red Sea, 

 from which sea the contrast in width and depth is so remarkable as to 

 suggest genetic independence rather than community of origin ; when 

 we contrast the shallowness of the Gulf of Suez with the more than 

 tenfold greater depth of the Gulf of Akaba; above all, when we 

 remember that secular movements are known to have gone on 

 comparatively recently in the district, 1 and that such a movement 

 downwards of less than 100 metres is all that is necessary to account 

 for the submergence of dry land to form the existing gulf; we must 

 feel hesitation at pronouncing the Gulf of Suez to be a trough- 

 subsidence. 



But that is not all. Let us consider the contours of the floor of the 

 Gulf of Suez, shown in the sketch-map on p. 5. This map is 

 reduced from a much larger one which I made, and the smallness 

 of the scale has rendered it impossible to show the contours at 

 10 fathom intervals; I have therefore shown only the 20, 40, and 

 100 fathom lines, which indicate the shape of the bottom of the gulf 

 sufficiently well for the purpose of discussion. The shape of the floor 

 of the gulf is exactly that of a great flat-bottomed valley such as the 

 Wadi Araba or the Wadi Qena. Even where the slope downwards 

 from the shore towards the centre of the gulf is steepest, as for 

 instance near Gebel Zeit, the 20 fathom contour is seldom within 

 half a mile of the coast, which only corresponds to a slope of about 

 1 in 40 ; and as the slope of the adjacent land is greater than this, 

 there is no sudden deepening, such as might indicate a trough-fault, 

 but rather a general continuity of slope from hill-top to sea-bottom. 2 

 Moreover, the fall of the sea-bottom lengthwise is practically continuous 

 from Suez to the Red Sea. 3 Another suggestive feature is that there 

 are indentations of the contours of the floor of the gulf opposite the 

 mouths of many of the wadies draining into it ; these indentations are 

 not very evident on the small-scale map, owing to the fewness of the 

 contours which can be shown; but they are more marked on the 

 larger scale, where the 10 and 30 fathom lines are drawn in. It is 

 extremely unlikely that the bottom of the gulf has been eroded in this 

 curious manner by deep currents ; the tendency of the sea will rather 

 have been in the direction of the silting-up of any pre-existing deep 

 hollows. "What is the only other deduction? Must we not conclude 

 that the Gulf of Suez is a submerged valley of erosion, by which the 

 wadies now draining from Egypt and Sinai to the gulf formerly 

 emptied their contents by trunk-channels into the Red Sea near what 

 is now the Island of Shadwan ? I have drawn the main lines of this 

 suggested former drainage system in the sketch-map, from which 

 I think the connexion between the existing wadies and the shape of 

 the floor of the gulf will be evident. 



1 Evidence of raised beaches. See Barron & Hume's Eastern Desert, p. 139. 



2 Becent coral reefs have in parts given rise to small steps in the slope near the 

 present water-line, hut it will be perceived that these have nothing to do with 

 the argument. 



3 The only break in the continuous slope down the gulf as shown by 10 fathom 

 contours is a slight rise of a few fathoms a little north of latitude 28. It is probable 

 that the soundings may have missed the very deepest parts here, or that silting or 

 coral-growth has filled up the hollows to the thickness of a few fathoms. 



