Geology of Mount Sinai and adjacent Countries. 47 



to the castle of Nakhl, on the east, a few miles off, low 

 chalky hills appeared ; and in places there were holes where- 

 in rock-salt had been dug. The water at Nakhl is brackish, 

 and the ground chalky, covered with loose pebbles. Wadi 

 Nesil was observed to be overgrown with green shrubs. 

 Gebel-el'Thuyhar, signifying " the mouths," presents a moun- 

 tainous tract, in which followed a valley with calcareous hills : 

 here deep sands were lodged, and large insulated rocks of a 

 porous tufa, called by Burckhardt tufwacke, lie scattered in 

 *"any places. 



" The termination of the vast gravelly plain we had been crossing 

 from Nakhl was now at hand ; but we could yet see it spreading 

 out wide to our left, the mirage giving its distant portions the ap- 

 pearance of a succession of blue lakes ; directly in front were the 

 mountains which close it in ; and far to the right we could see, 

 stretching away, a still higher range running to the north, and on 

 the left the tops of the mountains about Wadi Gharandel, the Taset 

 (cup) Soddur being conspicuous afar. We entered these mountains 

 by a slight ascent, which struck soon after the head of a long wind- 

 ing valley descending towards Suez : the immense plain we had 

 traversed, floated away in mist, and we had now done with the pla- 

 teau of the Great Desert." * 



Thence a plain, which is below the level of the Desert- 

 el-Tyh, and covered with moving sands, extends as far as the 

 sea-shore. These sands are collected by the winds, in many 

 spots, into hills 30 or 40 feet high. The wells at Mahuk afford 

 good water by digging to the depth of 10 or 12 feet. 



Fifthly, Once more leaving Suez ; after having passed over 

 a small piece of marine and alluvial formation near the sea, 

 and taking a westerly direction, a narrow tract of tertiary 

 sandstone, so designated by Russegger, is observed ; it is a 

 plain which gradually ascends from the shore of the Gulf, and 

 in it is placed the Castle of Afroud ; the water obtained there 

 is very bitter. Beyond this to the west, the plain becomes 

 sandy, and covered with black flints. 



But the soil and hills at Wadi Emshash, which signify the 

 *' Valley of the Waterpits," near Ajroud, are calcareous : 



* Bartl€tt'$ " Forty Days in the Desert," p. 167. 



