J. MILNE ON THE SINAITIC PENINSULA AND N.W. ARABIA. 19 



Hocks from Wady Ithm (the first five of these were examined 

 microscopically) : — 



1. Diabase, dark greenish in colour, compact and tough. 



2. Diabase, more compact than No. 1, from which it also differs iti 



containing a small quantity of disseminated iron pyrites. 



3. Dolerite, blackish green, dense and compact. 



4. Hornstone, whitish green, compact, crystalline, traversed by fine fissures 



containing carbonate of lime. 



5. Dolerite, greenish grey and compact. 



6. Granite, pinkish in colour and with little mica. 



7. Felsite, pinkish in colour, containing a very little hornblende. 



8. Porphyry, a pinkish base, with white crystals of felspar and a very 



little hornblende. 



9. Porphyry, differs from No. 8 in being slightly darker in colour. 



10. Granite, greyish in colour, of a coarse texture, and somewhat por- 



phyritic. 



11. Granite, pinkish in colour, with bronze-coloured mica. 



12. Porphyry, of a pink colour, with hornblende. 



13. Porphyry, differs from No. 12, in being of a greenish grey colour. 



14. Porphyry, fine-grained and without hornblende. 



15. Granite, consisting of felspar, mica, and very little quartz. 



16. Granulitic granite. 



1.7. Quartz-porphyry, of a pinkish colour. 



18. Porphyry, of a bluish grey colour. 



19. Syenite, of a dark-green colour, containing very little quartz, and very 



little hornblende. 



20. Porphyry pinkish grey and fine-grained. 



21. Porphyry, with hornblende. 



With regard to the granitic hills lying between Akaba and Petra, 

 as they have so many points in common, a description of one of 

 them may, in many respects, suffice for the remainder. The one 

 selected is Mount Baghir, also known as Jebel el Nur, or the 

 " Mountain of Light," which by Dr. Beke has been identified as 

 the true Mount Sinai (see fig. 2). 



This mountain, which is situated on the east side of Wady Araha, 

 and on the west side of Wady Ithm, which it overhangs, is about 

 100 miles in a north-easterly direction from the traditional Sinai, 

 and 12 miles from the fortress of Akaba. In its general outline it 

 is bold, terminating in three well-defined small peaks, which dis- 

 tinguish it from the surrounding hills. Measured from the plain, 

 out of which it rises, it is about 3000 feet in height, or about 5000 

 feet above sea-level. It consists of a mass of red or pinkish 

 granite, which in places where it is much weathered is of a dark 

 brown hue. In those places where disintegration has been at 

 work, the felspar and lighter mica have to a great extent been 

 washed away, leaving a rough gravelly surface of quartz, which 

 crumbles under the feet. This granite contains comparatively but 

 little mica ; and in places it merges into quartz and massive felspar 

 alone. On the north-west side of the mountain a portion of the 

 granite looks at a distance like a coarse brownish yellow sand" 

 stone, weathering with rounded surface, in which many cavities can 

 be seen, generally about the size of a cocoa-nut. In several large 

 boulders of this rock these cavities have so increased in size as to 



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