290, 



of tlie valley^ wliicli beloiii^ to a period of subsidence indicated 

 by similai' beds in other places^ and also by the raised beaches 

 and the rocks covered with modern oysters and boref^ by 

 lithodomous shells^ which are seen near Cairo and at Gizeh, 

 at the height of 200 feet above the sea. 



Along a wady or ravine cut through the bed by the 

 modern torrents, the ancient Egyptians have excavated 

 tombs in the hard gravel. But, independently of this, 

 a geologist would have little doubt as to its prehistoric 

 age. The doubt here lies with respect to the flints. The 

 bed is full of broken flints, as are the modern gravels carried 

 down the ravine at present, and indeed all gravels formed by 

 powerful torrents or surf-action in flint districts. These 

 result from the violent impinging of stones on the flints, and 

 therefore have all the characters of specimens broken by 

 hand, except that they have no determinate forms. In this 

 respect the broken flints found in these beds differ from those 

 found at Helouan, or in the bone caves of the Lebanon, and 

 resemble those which may be found in any bed of gravel 

 formed by violent mechanical action. It is true, a few out of 

 thousands of shapeless flakes might be likened to flat flakes 

 formed by man ; but the same proportion of such forms may 

 be found in the modern dphris of the torrents. The main 

 j)oint at issue in respect to these forms is the importance 

 attached to what is termed a "bulb of percussion,^' produced 

 by a sharp blow striking off a flake. That this is usually an 

 evidence of human agency may be admitted ; but since it 

 may be produced by the action of a water-driven stone, it 

 cannot be regarded as an infallible proof, except when sus- 

 tained by other evidences of the presence of man. 



The specimens figured as from this bed by General 

 Pitt-Rivers are in no respect exceptions to this, and I dug- 

 out many similar ones from the same beds, but none which 

 could with any certainty be assigned to human agency. I do 

 not, of course, refer to those which he describes from tombs 

 and from the surface, one of which is a finely-formed .knife, 

 with edges modified by pressure. Another, supposed to be 

 for scraping or polishing shafts of spears, is like specimens of 

 worn strike-lights from the pouches of modern Arabs. (PL II,, 

 Fig. 8.) The annular nodules figured by General Pitt-Rivers, 

 which are numerous in some of the limestones, of course 

 have no connexion with the worked flints, and the specimens 

 which he figures from the surface, though some of them are 

 no doubt ancient, are probably in part natural and in part 

 from the little heaps left by Arabs and others in places 

 where they have been shaping flints for muskets or for 



