60 



Visit to Mount Sinai. 



[No. S3, 



known to cap the peaks of Sinai during the winter months, no doubt 

 adds to the force of these Wadi torrents. 



It appears to me that much of this gravel which cannot be account- 

 ed for by existing causes of transport, was accumulated during oscil- 

 lations of the surface of the land. 



Underneath the surface of the sand, especially near the head of the 

 gulf of Suez and in many places rising in small hillocks above it, we 

 see thin beds of a grey and greenish clay, sand and marl, often lami- 

 nated, imbedding layers of lamellar crystallized gypsum and muriate 

 of soda or rock-salt and sometimes existing pelagic shells, also littles 

 mounds abounding in little worn fragments of Egyptian pebble, jas- 

 pers, and hard calcareous stones, light coloured interiorly ; but of a 

 dark brown exterior, evidently stained with oxide of iron, which has 

 a tendency to blacken when in contact with calcareous matter. This 

 dark appearance is so remarkable that Niebuhr and others after him, 

 thought the stones had been blackened by the sun. The water of 

 the wells rising in these saliferous beds is usually brackish as might 

 be expected. Raised beaches of recent coral a few feet high, occur 

 at Tor and many other places on the Red Sea. According to Riip- 

 pell there is a raised coral beach, 13 feet above the sea level, at 

 Ras Mahomed. 



, . „ , Laborde and others have doubted the existence of 

 Volcanie Rocks. •, . ^ 



volcanic rocks on the pemnsula of Sinai, from not 



having observed them, and from Riippell's arguing their absence 



from not finding titaniate of iron mingled with the sand brought 



down by its streams. Burckhardt distinctly states their occurrence 



to the south near Shurm, on the east coast north of Ras Mahomed, 



as black and red rocks, forming crater-like configurations. He also 



mentions basaltic tufa composing low hills between Wadis Ruman 



and Mukatteb. They are no doubt rare, 



^ Regarding the supposed age of the different rock 



Ages of the „ 



Rocks of Si- formations, Burckhardt and Professor Robinson, from 

 whose valuable works a large share of the informa- 

 tion contained in this sketch has been derived, say nothing and 

 indeed tell us little, beyond the surface changes, from sandstone and 

 limestone, to granite gneiss and griinstein as they travelled along, 

 —observations however, extremely useful and to be prized. 



As it is, nothing beyond the relative ages of the rocks, except the 



