482 E. A. JOHNSON PASHA AND ME. H. D. EICHMOND 



Between Cairo and Assouan the first geological feature of import- 

 ance is the great fault at Maghagha, where the whole mass of 

 strata south of the dividing-line has been depressed some 500 feet 

 and tilted at an angle of 30°. The rocks at the water's edge on 

 the southern side of the fault correspond with the summit of the 

 hills on the north. The fault brings to light great beds of dark 

 grey and green clays beneath the limestones and the hard chalk 

 Avhich underlies these, and it seems possible that the collapse of the 

 strata may be due to the action of the water on these clays. The 

 fault runs nearly due E. and W. and seems to extend to a consider- 

 able distance into the desert. It is remarkable that those rocks on the 

 southern side which have sunk to the water's edge are less water- 

 worn than similarly situated rocks throughout the length of the 

 river ; this perhaps may indicate that the faulting has occurred in 

 comparatively recent times. 



The next peculiar feature is the limestone on the eastern bank 

 from Kolosna to Sheikh Abadeh, which presents a vast field of 

 * hummocks ' consisting of highly crystalline limestone full of small 

 holes. 



Erom near Minieh to Assiout and for some distance south the 

 most striking feature is the increased number of pockets, hollows, 

 and fissures existing in the limestone-rocks ; and the fact that these 

 are filled with, or have been for the most part filled with, clay 

 strongly impregnated with iron, and containing numerous small 

 streaks and patches of dioxide of manganese in a very fine state of 

 division, or a mixture of dioxide of manganese with clay, &c., and 

 carbonate of lime, also finely divided, and averaging 40 % dioxide 

 of manganese, 20 7o carbonate of lime, and 40 % ^^ ^^^J- The 

 chemical evidence points to this partaking somewhat of the character 

 of a calcium manganite, and it has possibly been formed by the per- 

 colation through the limestone of water containing manganese salts 

 in solution. At some distance from the Nile manganese alums 

 abound, and these may possibly have formed the dioxide, or a 

 common source may perhaps be ascribed to both. Many of the 

 tombs in the rock have been pockets of manganese, and in one 

 set at Assiout blocks of this manganese were found piled up in a 

 corner, suggesting that it had been used for an unknown purpose by 

 the ancient Egyptians. 



In Jebel Abou Eouda there are disturbances apparently due to 

 the collapse of underlying strata. 



From a point near Keneh to Luxor and thence to Esneh we find 

 a limestone which is practically chalk-with-flints, forming the lower 

 of the limestone beds ; and below this are grey and green clays from 

 200 to 300 feet thick, full of nodules of haematite, the smaller nodules 

 being of great purity, and apparently often used by the ancient 

 Egyptians to cut scarabs. The larger nodules are in general less 

 pure, and are in great part reduced to ochre, often of a very beau- 

 tiful colour. The fossils of these clays, which are Cretaceous, are 

 impregnated with iron and are dark brown in colour. A thickness 

 of fully 300 feet of these beds is exposed in the high hiUs about 



