Vol. 67.] DURING THE CRETACEOUS AND EOCENE PERIODS. 121 



Alternation of Sandstones and Upper Cretaceous 

 Limestones. 



Wadi Qena is a wide expanse, bounded on the west by the 

 precipitous cliffs of the limestone plateau, which has its western 

 termination in the scarps bordering the Nile Valley. On the east, 

 in sharp contrast with the uniform flat-topped rock-wall of the lime- 

 stone plateau, are the serrated and multi-coloured granitic peaks or 

 the more monotonous greenish dioritic, volcanic, and metamorphic 

 members of the Red Sea Hills, while between them lie broad plains, 

 out of which rise brown tabular outliers of Nubian Sandstone. 



Between the main drainage-line of Wadi Qena (which itself is 

 relatively rich in vegetation) and the western scarp is a confused 

 country of low hills, terminating towards the valley in a secondary 

 well-marked cliff varying from 50 to 150 metres in height. 



Until last year (1910) this country had not been geologically 

 examined ; but, although details still require elucidation, the broad 

 features are clearly revealed. It owes its present character to a 

 conformable succession of Cretaceous strata dipping on an average 

 3° westwards (varying from south-west to north-west), which are 

 probably some 300 metres thick. They are especially well developed 

 in the watershed region at the head of Wadi Qena, where three 

 great drainage-systems meet, one of the sections studied being in 

 Wadi Hemaiet, which descends from the limestone plateau to Wadi 

 Qena, and thus to the Nile at the town of Qena ; a second section 

 in Wadi Abu Had, which, rising near the head of Urn Hemaiet, 

 descends rapidly to the Gulf of Suez; while the third section was 

 exposed in the low hills separating Wadi Hawashia from Wadi 

 Tarfa, the latter being a great drainage-line which joins the Nile 

 not far from Minia. 



The most important feature in these sections is the threefold 

 repetition of strata typical of the Nubian Sandstone, between beds 

 the fossil contents of which definitely fix their age : so that we may 

 here speak of an Upper, a Middle, and a Lower Nubian Sandstone, 

 the two first-named from their associations being indubitably Upper 

 Cretaceous, while the lower division is not readily separable from 

 the Cenomanian strata which it underlies. The most notable divi- 

 sions recognized may be thus summarized : — 



The highest beds of the series are displayed in the precipitous 

 cliff- face which forms the eastern termination of the great lime- 

 stone plateau east of the Nile. These were recorded as members 

 of t-he Nummulitic Series by Dr. G. Schweinfurth, 1 but the ascents 

 made on these somewhat dangerous scarps show them to be com- 

 posed in their upper part of 



1. A white limestone weathering to a biscuit colour, and containing broad 

 tabular bands of flint or large isolated concretions (an example 

 measured 60 X 40 cm.) of the same material. This is underlain by 



1 Dr. Schweinfurth has published an excellent series of topographical maps 

 with geological notes, embracing most of the Eastern Desert north of 26° N., 

 and issued by Dietrich Eeimer, 29 Wilhelmstrasse, Berlin. 



