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



4. Diabase, slightly greener than Nos. 2 & 3. 



5. Red Porphyry, compact, fine-grained, with hornblende. 



6. Granite, highly felspathic, with but little mica, of a pinkish colour. A rock 



penetrated by dykes. 



7. Granite similar to No. 6, but baring small fissures containing dolomite. 



8. Granite, similar to No. 6, but containing two felspars — one tr iclinic, and the 



other orthoclase. 



9. Granite, greyish and much disintegrated, and thickly traversed by dykes. 



10. Porphyry, a dark-coloured base thickly covered with small white crystals of 



felspar. 



11. Porphyry, like No. 10, but with the felspar crystals long and aeicular. 



12. Dolerite, with brewnish yellow olivine, of a vesicular structure, the cavities 



being in part filled with carbonate of lime. This was obtained from a 

 boulder, of which there are many, all probably having their origin further 

 up the wady to the east. 



13. Degraded Basalt, like No. 1, both being found in small angwlar fragment* 



in the interior of a dyke on the east side of the wady. 



Madian to Omaider. — From Madian, continuing northwards along 

 the east side of the Gulf of Akaba, the sandstone continued for some 

 4 or 5 miles, but in places apparently pierced by the granite, which 

 at one time it probably covered, and towards the flanks of which it 

 was now approaching. 



On the west side of the gulf, although the hills were 15 miles 

 distant, the dykes by which they were penetrated were distinctly 

 visible. 



As we neared the granite on the eastern side, the sandstone 

 gradually sloped up towards it, or, in other words, dipped to the 

 south or south-east, suggesting the idea just stated, that at one time 

 it wholly buried these mountains which now raise themselves s© 

 high above it. When we were opposite what ought to have been 

 the line of junction of the two, the stratification of the sandstone 

 became so broken, and the outline of the decomposing granite so 

 indefinite, that the relation of the two was not distinctly visible. 

 The next object of geological interest was a flank of Jebel Tauran, 

 which projected as a prominent bluff, the face of which formed a 

 high and almost perpendicular cliff, through the centre of which was 

 a canon-looking gulch cleaving it from top to bottom. The height 

 of this, if any reliance can be given to a rough calculation based on 

 its altitude as taken by our captain, must have been over 2000 feet, 

 which would almost put the crevasse-like opening on a par with a 

 "Western- American canon. 



Bir el Mashiyah. — A few miles to the north of this is the head- 

 land of Bir el Mashiyah, at which place another opportunity was 

 given for visiting the shore. Here there is decided evidence that 

 the land of this gulf and, probably in connexion with it, that of its 

 neighbour the Gulf of Suez, are rapidly rising. 



Running from the granite hills, which here recede some three or 

 four miles from the shore-line, across a gently sloping plane which 

 joins them with the sea, there are numerous regularly built mounds, 

 like so many partially completed railway embankments, reaching 

 from the mountains to within half a mile of the water's edge. These 

 appear externally to be made up of materials derived from the hills 



