262 John Hogg, Esq., on the Geography and 



But the extensive and narrow plain El Kaa, in particular 

 between Tur and Wadi Hebron, is, according to Captain 

 Newbold (p. 55) : — 



" Covered with sand generally of a coarse quartzose nature, often 

 strewn with a gravel composed of fragments of the granitic and hypo- 

 gene rocks, both angular and rounded, from the size of a pea to that 

 of an orange ; the pebbles are principally of reddish granite, porphy- 

 ritic and close-grained Aorn6Zen<ie schists, greenstone, compact /VZspar, 

 coloured green with actynolite, — actynolite with quartz and felspar 

 in drusy crystals, — and porphyry of various descriptions, including 

 melaphyre. The most prevalent variety is like that of Egypt, being 

 composed of a brownish felspathic paste imbedding felspar crystals of 

 a light reddish-brown, white, and of a pink hue ; also a black augitic 

 paste imbedding crystals of red, white, or pale green felspar.^^ 



'* The rocks in Wadi Hebron are of a granitoidal gneiss in nearly 

 vertical strata (or lamince) penetrated by granites, dykes of green- 

 st07ie, and porphyry,'''' 



At the east end of Wadi Firan, near Wadi Selaf, " the 

 rocks are principally of hypogene schist, gneiss, mica, felspa- 

 thic actynolite, chlorite, and hornblende schist^ Whilst those 

 " from Nakb Hawi to (the modern) Mount Horeb are chiefly 

 granite, porphyritic granite, hvown porphyri/, in veins or dykes 

 in granite, and hornblende rock. All these rocks are pene- 

 trated by enormous dykes oi greenstone ; near which veins of 

 compact greenish felspar and eurite are not uncommon in the 

 granite ; also pegmatitic veins, and veins of felspar coloured 

 green by actynolite.''^ 



" The red granite (of the high Sinaic ^roup) is often por- 

 phyritic," and " penetrated by dykes of brown and black por^ 

 phyry."* 



But M. de Roziere and others of the French Scientific Ex- 

 pedition to Egypt have given the term of " Sindite'' to that 

 species of granite, — composed chiefly of felspar in confused 

 laminse, and of much hornblende (amphibole) without quartz 

 or mica, — forming the principal rock of the higher Sinaic 

 district. 



Captain Newbold further says, " the rock composing Gebel 

 Mineggia is principally of a chloritic hornblende and a white 



* Newbold, in loc. cit., pp. 61, 68, 69. 



