Geology of Mount Sinai and adjacent Countries. 41 



stretches out to an almost indefinite extent. To the west and 

 north, and around Mount Hor, lofty party-coloured sandstone 

 ridges and cliffs prevail ; then succeed high masses of por- 

 pltyry^ constituting the body of the mountains, but lower than 

 the sandstone. And, lastly, more northwards, the chain sinks 

 down into low hills of argillaceous rock, or of limestone. 



The entire breadth of the Seir range seems not to exceed 

 eighteen English miles, between Wadi-el-Araba and the 

 Eastern Desert ; whilst that of the more northern, or Na- 

 hathman chain, does not exceed twenty-two miles between 

 those districts. 



Going west from Petra, the valley of the Araba is again 

 entered, where the deeper Wadi-el-Jeib is seen to wind along, 

 very near the middle of it, from the south, then sweeping off 

 NW., it meets the Wadi-el-Jerafah, which comes in from the 

 SW. Afterwards, it is called only Wadi-el-Jeib ; and being 

 a deep valley within a larger valley, it forms the chief water- 

 course of the greater portion of the Araba, and carries down 

 to the Dead Sea, in the wet season, an immense body of 

 water. 



El Araba, more to the north of Gebel Harun, is much 

 wider ; in parts of it there are gravel hills ; and here and 

 there, masses oi porphyry lie about in the sand, having been 

 washed down by the torrents. Eleven or twelve miles north 

 of that Mount {Hor), occurs the pass of Nemela among low 

 hills of limestone, or rather a yellowish argillaceous rock, the 

 dark steep mass of the mountain he'ing porphyry, as before de- 

 scribed ; thence the Wadi ascends between the porphyry and 

 limestone formations ; and on the top is a little basin of 

 yellow sandstone capping the porphyry. 



Coming back southward through the Wadi-el-Araba, as far 

 as the embouchure of the valley of the Jerafah — meaning 

 " gullying," — which is about a mile wide, the mountains on 

 this west side are found to be composed of chalk and lime- 

 stone ; and, in many places, with large pieces of black flint. 



On the north, and to the east of Lussan, the mountains of 

 Idumsea are lofty, consisting of precipitous limestone ranges ; 

 the solitary conical mount, about 600 feet above the plain, 

 named Gehel Araif-el-Naka — " the crest of a she-camel," 



