Geology of Mount Sinai and adjacent Countries. 257 



to a whitish grit as at Gebel Nark us, and to variegated sandstones, 

 as at Wadi Murrah." 



" The extensive sandy tracts and dunes in the interior, which 

 usually mark the vicinity of this formation, are the result of the 

 weathering of the less consolidated beds of this rock.** But ** the 

 drifts of fine blown sand, which are so remarkable on the sides of 

 the ranges that skirt the Red Sea, have evidently been" carried 

 thither by the winds from the sandy beach. 



" The low maritiiiie plains are usually covered with satid, and 

 sometimes with 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 account 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 consi- 

 derable thickness, and which, on the eastern coast, as Professor 

 Kobinson informs us, reach from the base of the mountains to the 

 sea, sometimes in beds many feet thick." Captain Newbold " exa- 

 mined the beds at the mouth of Wadi Hebron where it opens into 

 the plain of El Kaa, under the impression that they might be ancient 

 moraines, but found the pebbles rounded, of moderate size, or smaller, 

 regularly inter-stratified with layers of sand, and no signs of glacial 

 action on the rocks." 



" Underneath the sand, especially near the head of the Gulf of 

 Suez, and in many places rising in small hillocks above it, are seen 

 (strata of tertiary limestone and marl, consisting of) thin beds of 

 a grey and greenish clay, sand, and marl, often laminated, imbed- 

 ding layers of lamellar crystallized gypsum, rocksalt, and sometimes 

 existing sea-shells, also little mounds abounding in slightly-worn 

 fragments of Egyptian pebble, jaspers, and hard calcareous stones, 

 light coloured interiorly, but of a dark-brown exterior, evidently 

 stained with oxide of iron." 



Of course, " the water of the wells rising in these saliferous 

 beds is usually brackish. Raised beaches of recent coral., a 

 few feet high, occur" in many places along both gulfs. 



Volcanic rocks are related by Burckhardt to be situate 

 near Sherm, to the north-east of Ras Mohammed, and are 

 described " as black and red rocks, forming crater-like con- 

 figurations." He likewise mentions black basaltic clifi's and 

 creeks on the same coast, west of the isle of Kureiyeh, and 

 low hills of basaltic tufa, near the junction of Wadi Firan 

 with Wadi Mukatteb. 



VOL. XLIX. NO. XCVIII.— OCTOBER 1850. R 



