156 Messrs. Barro)i (^' Hume — EasteDi Desert of Egypt. 



are distinguished more or less from the lower by a different fauna. 

 The disturbed reef has been formed previous to the formation of the 

 parallel ranges of Jebel Esh and Zeit, thus bringing up the fault- 

 movement to very recent times. 



In this area there is an inversion of the stratigraphical arrangement, 

 the higher beds being the older, the reefs being formed during 

 -a period of secular elevation. There is also apparently a long break 

 between the two reefs, the explanation suggested being as follows : — 



The first great Tertiary earth-movement in the Ked Sea region 

 was previous to the Upper Miocene and subsequent to the Eocene, 

 •the latter being faulted, and beds of the former deposited in the 

 troughs produced. Later, as the result of further movements, coral 

 reefs were formed on the sides of the igneous hills, but as soon as 

 (owing to continued elevation and denudation) valleys had formed, 

 down which torrents carried masses of pebbles, etc., the conditions 

 became unfavourable for the formation of true reefs, and only gravels 

 were deposited. This view assumes the existence of marked pluvial 

 conditions, as maintained by previous writers, and it was only when, 

 the present desert conditions set in that the reefs again began 

 to grow. 



2. Pliocene, — Mayer-Eymar and Dawson have both regarded the 

 Nile Valley as an arm of the sea in recent times as far up as Assuan. 

 A foraminiferal limestone, found by Mr. Barron near Erment and 

 which has been described hy Mr. F. Chapman, contained two out of 

 :five species described not older than Miocene, while one is not 

 known before Pliocene times, thus proving the above theory. Beds 

 of the same age are found in Wadi Qena. They form a plateau 

 consisting of flint conglomerates, white limestone, and at the base 

 marls and fissile sandstones which vary greatly, the limestones 

 being lenticular and thinning out to the east. The conglomerates 

 are formed by the denudation of the Eocene limestone. The 

 succession of these beds is as follov^^s : — 



(1) On the boundai'y-line with the Eocene rocks, breccias of flinty 



and cherty limestone with lenticles of limestone interbedded. 



(2) Conglomerates of well-rounded pebbles. 



{3) Pure white limestones, perhaps partly siliceous. 

 (4) Marls and clays. 

 (o) Sandy clays. 



These beds are regarded as Pliocene on three grounds — (1) They 

 have no resemblance to known Miocene beds in Egypt ; (2) they 

 are identical in all essential particulars with the foraminiferal series 

 of the Nile Valley; and (3) the Pleistocene gravels are younger and 

 unconformable to them. 



These beds owe their origin to the faulting which produced the 

 Nile Valley and Wadi Qena, and there must have been a subsidence 

 of at least 400 metres to allow of their deposition. 



The Pliocene has been a period of great movement marked by the 

 formation of the great rifts such as the Eed Sea, with the invasion 

 of the fauna of the southern seas, the Grulf of Suez, the great scarp 

 of the Ked Sea Hills and its parallel ranges, and the main trend of 



