J. MILNE ON THE SINAITIC PENINSULA. AND N.W. ARABIA. 13 



operation, as appears to be indicated, it is very probable that at no 

 very remote geological period the Gulf of Akaba extended many 

 miles further to the north, having been bounded on its east and 

 west sides by the before-mentioned high tablelands ; and should 

 this ancient gulf be restored (which would apparently be an en- 

 gineering work far less difficult than the recently constructed trench 

 between Suez and Port Said), Jerusalem, Damascus, and other Syrian 

 towns would again be in communication with the Indian Ocean, 

 and fleets like those of Solomon might ply up and down the now 

 entirely deserted Gulf of Akaba. 



The section illustrating this depression (fig. 2), which will explain 

 itself, is only an approximation, and is here used to add my obser- 

 vations to similar ones that have been made by others on this 

 singularly interesting depression. 



Akaba. — At Akaba (fig. 2), as at many other places, the granite 

 is traversed by so many dykes that they could not but take part 

 in the formation of peaks. Their general direction is in a parallel 

 line towards the north-east, and at a high angle of inclination to the 

 south-east. 



Behind Akaba, two good analogous sections are to be seen on the 

 eastern side of Wady Araba, at the entrance to a small wady called 

 Wady lthra. The surface of the ground through which these 

 sections are cut commences about half a mile from the sea, and 

 terminates at a distance of a little over a mile, sloping at an angle 

 of about 3° up towards the mountains. The distance apart of these 

 sections at their upper or eastern end, where they are about 30 feet 

 in height, is about 100 yards, and at their lower or western end, 

 where they merge into the sloping plane through which they are 

 cut, about half a mile. 



Looking at these generally, they consist of a mass of earth, 

 pebbles, and boulders, lying on the denuded edges of granitic rocks 

 and felspathic dykes. The pebbles and boulders are of the same 

 nature as the rocks on which they lie ; and at the eastern end of the 

 sections near the mountains it would appear that the pebbles, and 

 especially the boulders, are not only larger but also more angular 

 than those a mile further away. 



The mode of accumulation of the upper stratum of alluvial 

 material is strikingly shown at several points along the section. 

 The material, starting from the mountains (which at one time 

 probably extended a short distance westwards), through various 

 causes, but chiefly that of gravity, gradually travelled down the slope 

 towards the sea. On coming to a hollow it steadily filled it, the 

 stones of each layer rolling over their predecessors until the original 

 slope was regained, the result of which has been to give, at different 

 points along the section, several groups of radiating bands. 



The granite is of a pinkish colour, and consists chiefly of felspar 

 and a little quartz, whilst the mica is barely visible. It contains 

 numerous dykes, which vary from dark green to olive-green in colour. 

 At the junction of several of these with the granite, and running 

 through them both, are flakes of white carbonate of lime about 



