lii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



found Ms party mounted at length on one among forty- seven sharp 

 peaks, Trithin a space of perhaps a thousand metres, and observed 

 that each peak was formed by a dyke of diorite which, with its tough 

 material and angular structure, had resisted the action of the weather 

 in a far higher degree than the granite. In the group of Mount 

 Horeb (Jebel el Tur) and its central pillar (Jebel Musa) the same 

 varieties of crystalline rock occur, but on a larger scale, the apha- 

 nitic greenstones being no longer in dykes of a few feet in width, 

 but in vast masses ; and a diiFerent and more majestic character is 

 thus imparted, to the mountain, which induces Dr. Fraas, although 

 leaning to the opinion of Lepsius that the Serbal is probably the true 

 historical Sinai, to acknowledge the force of the claim urged by the 

 Greek monks for the superior sanctity of the Mountain of Moses. 



The mounds of fragmentary^ matter, 40 or 50 feet high, which 

 sometimes bar up transversely, and in other cases are heaped along 

 the sides of the valleys, have been commented upon by former visitors; 

 but we now have them, for the first time, I believe, confidently re- 

 ferred to the action of glaciers. The materials of the detritus in the 

 AYadi Hebran, and in the valley of Eeii^an, blocks and stones of all 

 sizes, from 1000 cubic yards to mere sand and gravel, tumultuously 

 tumbled together, are pointed to as being aggregated in such a manner 

 as no other imaginable agency could aggregate them ; and the walls of 

 rubbish, through which the modern winter- streams have cut narrow 

 channels, are piled across the principal or the secondary valleys pre- 

 cisely in the manner of terminal and lateral moraines. Not that the 

 Stuttgart professor deems it needful to refer these phenomena to the 

 Glacial period of Europe ; he sees in the southern part of the penin- 

 sula no trace of Tertiary or Secondary deposits, and thence assumes 

 that Sinai has been dry land from the earhest periods, and that 

 " these glaciers may as well date from the Silurian period as from 

 that of the Jui'a, or from the Tertiary." 



Another suggestion of startling novelty is that put forward in ex- 

 planation of the peculiar form of the wadis. These arid and rock- 

 bound valleys, partially occupied by a rush of water after the wintry 

 rains, present on the west a narrow entrance which the traveller 

 coming from Egj^Dt, until he actually enters them, makes out with 

 difficulty, from the lofty cliffs through which they are opened. 



Eurther and further in, as you advance towards the nucleus of 

 the higher mountains, the wadi opens out wider and wider, 

 without any such change being noticeable in the rock as might 

 have led to its easier disintegration ; and at length, at its head, it 

 becomes a broad flat valley, in which you can with difficulty mark 

 the exact line whence the waters would flow in an opposite direc- 

 tion, but where it is to be observed that, instead of contracting 

 again as on the west, it opens out to a still broader wadi, debouch- 

 ing at length from the high ground. These features would be ex- 

 plained, our author believes, on the supposition that the levels of 

 the country have been greatly changed in comparatively recent 

 times, and that, before the opening of the Eed Sea, the Sinaitic 

 group and the old Mons porphij rites of Egypt were so connected that 



