198 Dr. W. F. Hume—Eift Valleys of Eastern Sinai. 



Ill, — The Eift Valleys of Eastern Sinai. ^ 

 By W. F. Hume, D.Sc, A.E.S.M., F.G.S., etc. 



IN this paper the author deals with some of the results obtained 

 in the course of a survey of Eastern Sinai during the season 

 of 1898-99, his remarks being based on a map carefully prepared 

 by his colleague, Mr. H. G. Skill, F,R.G.S., and on his own 

 topographical and geological observations. 



The region speciall}^ under consideration is bounded on the west 

 by the central range of Sinai, which is familiar to every Indian 

 traveller, forming as it does a prominent rock-wall to the east of 

 the Gulf of Suez. This mountain mass in reality consists of a series 

 of narrow crests separated by few but high moimtain passes, and 

 capable of being traversed only by heavilj^ loaded camels at two 

 points, viz. at the head of Wadi Tarfah and Wadi Plebran. If this 

 range be crossed, and Mount Sinai (Jebel Musa) itself ascended, 

 the view to the east is decidedly disappointing. To the north-east 

 the long white limestone wall of Jebel Gnnnah runs more or less 

 east and west, far to the east breaking into isolated masses, and 

 ending in the fine truncated cone of Jebel El Ain. South of, and 

 parallel to it, extend sandy plains and precipitous plateaux of 

 sandstone, these being succeeded by an apparently flat or undulating 

 granite plateau (the rift- valleys in it being hidden), out of which 

 sharp-peaked mountain masses rise as isolated projections or long 

 ridges. To the south-west is a mountain-wall, which hides all the 

 southern land from view, and constitutes the most important scenic 

 feature in Eastern Sinai, extending across the country from the 

 Central Kange to the Gulf of Akaba. This Transverse Divide claims 

 special attention, not only from the fact that it sepai'ates two different 

 types of country, but also because at many points these two regions 

 are at markedly different levels, there being an abrupt fall to the 

 south. The divide is also crossed by five passes, which all have this 

 remarkable feature in common, viz. : that the valleys they connect form 

 Jive roughly straight lines, all parallel to one another and to the Gidf of 

 Ahaha, that is, running in a direction someiohat west of south. Two 

 of these are then specially considered with a view to showing that 

 they belong to the category of Eift Valleys, of which the Gulf of 

 Akaba is itself a striking example, it being premised that these are 

 not necessarily single depressions, but rather a series of basins or 

 grooves separated by barriers, which, though higher than the main 

 valley, are of no great altitude compared with the bordering hills. 

 Thus, the Shelala Um Eaiyig rift is shown to have a length of over 

 72 kilometres, being almost perfectly straight and bounded by very 

 steep slopes throughout the greater part of its course. 



The geological features are still more striking, the hills on the 



* Abstract of a paper read by permission of Sir William Garstin, Under-Secretary 

 of State for Public Works, and Captain H. G. Lyons, R.E., Director- General of 

 the Egyptian Survey Department, before the International Geological Congress- 

 at Paris, August, 1900. 



