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MR. H. J. L. BEADNELL ON THE EOCENE AND [NOV. K)0^ r 



Cretaceous beds are found 

 at their proper level, 400 

 metres (1312 feet) above 

 the sea. We must there- 

 fore assume a fault of some 

 300 metres (984 feet) 

 downthrow, as high-flood 

 level at Pares is only 90 

 metres (295 feet) above 

 the sea. It is possible that 

 this estimate may be ex- 

 cessive, as the difference 

 in level of the limestones 

 at river-level and identical 

 beds in the scarp of El 

 Borga may be partly due 

 to the disintegration and 

 removal of the argillaceous 

 deposits. It seems prob- 

 able, however, that faulting 

 was the primary cause of 

 the great plain of Kom 

 Ombo, which may perhaps 

 be regarded as a ' graben ' 

 of some magnitude, the 

 Eocene and upper lime- 

 stones and clays of the 

 Cretaceous forming a floor 

 surrounded by a range of 

 Nubian - Sandstone hills.. 

 The accompanying figure 

 is a generalized section 

 across the region from 

 Jebel Silsila to Darau. 



(2) Jebel Silsila. 



The Kom - Ombo plain 

 has two outlets through 

 the bounding sandstone- 

 range to the north; they 

 are about a kilometre 

 (= two-thirds of a mile) 

 apart, and at the present 

 day the river occupies the 

 westernmost of the two, 

 cutting through the hills 

 known as Jebel Silsila. 

 Schweinfurth described the 

 river here as runnings 

 through a narrow channel 



