1847.] 



Visit to Mount Sinai. 



49 



I am not aware that it has been seen south of this on either side of 

 the Peninsula, but it will probably be found lower on its eastern flank. 

 At Jebel Nakus it appears insulated from the granite and hypogene 

 schists, amidst a formation of tertiary limestone, I could discover no 

 traces of the former rocks in situ in this locality, though the proba- 

 bility is they are at no great distance below its base. 



Near the eastern coast it caps the hornblende rock at Ograt el Faras 

 and hence to Wadi Murrah and El Ghor. It caps the granite of 

 Jebel Sumghy, Es Sadeh and northerly it is seen occasionally rest- 

 ing on the granitic rocks, as at Muzirk and Ras el Musry to the head 

 of the Akaba gulfe 



In lithologic character it varies from a compact reddish quartz rock 

 as at the western mountain near Tor to a whitish grit as at En Nakus 

 and to variegated sandstones as at Wadi Murrah. 



The extensive sandy tracts and dunes in the interior which usual- 

 ly mark the vicinity of this formation, are the result of the weather- 

 ing of the less consolidated beds of this rock and which possibly in 

 some cases never have been consolidated. This remark is however 

 not intended to apply to the drifts of fine blown sand v/hich are so 

 remarkable on the sides of the ranges which skirt the Red Sea ; and 

 which have evidently been blown up from the sandy shore. 



More recent de- The low maritime plains are usually covered with 

 posits. g^j^^j sometimes vfith a gravel which as on the 



plain of El Kaa has been transported a considerable distance from 

 the granitic rocks in the interior. This gravel it is easy to ac- 

 count for in the beds of the Wadis by the action of the mountain 

 torrents, which come down occasionally with great violence during 

 the rains ; but a considerable portion of it is now far remote from 

 their present action. It is however in greatest abundance near the 

 mouths of the Wadis which have in many cases cut their channels 

 through beds of it of considerable thickness, and which on the eastern 

 coast, as Professor Robinson informs us, reach from the base of ths 

 mountains to the sea, sometimes in beds feet thick. 



I examined the beds at the mouth of Wadi Hebron where it opens 

 into the plain of El Kaa, under the impression that they might bs 

 ancient moraines but found the pebbles of moderate size and smaller, 

 regularly interstratified with layers of sand, and no signs of glacial 

 action on the rocks. The rapid melting of the snows which are 



G 



