276 report— 1884. 



consisting of agglomerates, tnffs, and beds of felspathic trap. The author 

 is disposed to concur with Dr. Lartet in considering the gneissose and 

 granitoid rocks to be of arcbcean (or Laurentiau) age, as they are pro- 

 bably representative of those of Assouan in Upper Egypt, which Principal 

 Dawson has recently identified with those of this age. The granites and 

 porphyries are traversed by innumerable dykes of porphyry and diorite, 

 both throughout the Sinaic mountains and those of Edom and Moab ; and 

 the author considers it probable that the volcanic rocks which are largely 

 represented along the base of Mount Hor, and of Jebel Somrah near Es 

 Safieh, are contemporaneous with these dykes. As far as the author was 

 able to observe, none of these dykes penetrate the Desert or Nubian 

 sandstones, and if so, they may be considered of pre- carboniferous age. 

 The upper surface of the ancient rocks was extremely uneven previously 

 to the deposition of the Desert sandstone, having been worn and denuded 

 into ridges and hollows ; over this irregular floor the sandstone strata were 

 deposited. 



'4. The occurrence of terraces of marl, gravel, and silt, through which 

 the ravines of existing streams have been cut at an elevation (according to 

 aneroid determination) of about 100 feet above the level of the Mediter- 

 ranean, was taken to show that the level of the Salt Sea (Bahr Lut) at 

 one time stood about 1,400 feet higher than at present. These beds of 

 marl were first observed at the camp at Ain Abu Beweireh ; they contain 

 blanched shells of the genera Melanopsis and Melania. The beds of marl 

 were observed to be enclosed by higher ground of more ancient strata in 

 every direction except towards the north, where they gently slope down- 

 wards towards the borders of the Ghor, and become incorporated with 

 strata of the 600-feet terrace. 



' The author concurs with Dr. Lartet in thinking that the waters of the 

 Jordan Valley did not flow down into the Gulf of Akabah after the land 

 had emerged from the sea; the disconnection of the inner and outer waters 

 was very ancient, dating back to Miocene times. 



' The occurrence of beds of ancient lakes, consisting of coarse gravel, 

 sand, and marl, amongst the mountains of Sinai, and in the Wad}' el 

 Arabah, where now only waterless valleys occur, taken in connection 

 with other phenomena, have impressed the author with the conviction 

 that the former climatic conditions of Arabia Petrsea were very different 

 from those of the present day. Such terraces have been observed by Dr. 

 Post in the Wady Feiran, and Colonel Sir C. W. Wilson in the Wady 

 Solaf, and by the author in the Wadies Gharandel, Goweisah, Hamr, 

 Solaf, and Es Sheikh or Watiyeh. It would appear that, at a period 

 coming down probably to the prehistoric, a chain of lakes existed amongst 

 the tortuous valleys and hollows of the Sinaitic peninsula. The gypseous 

 deposits of Wady Amarah and of 'Ain Hawareh are old lake beds, and 

 Mr. Bauerman has observed remains of fresh- water shells {Lijmnaa trun- 

 catitla) and a species of Pisidiura in "lake or river alluvium" of the 

 Wadies Feiran and Es Sheikh. 1 



' 7. The author considers it probable that these ancient Sinaitic lakes 

 belong to an epoch when the waters of the Mediterranean and the Red Sea 

 rose to a level considerably higher than at present, and when, consequently, 

 there was less fall for the inland waters in an outer direction. The 

 evidence of a submergence, to a depth of at least 200 feet, is abundantly 



1 Quart. Jour. Geol. Soc, vol. xxv. p. 32. 



