131 



The author then reviews the chief facts made known by the 

 ninety-five probings of the alluvial land above described, and gives 

 the following results : 



1. That the alluvium consists of two principal kinds, viz. an argil- 

 laceous earth or loam more or less mixed with fine sand, and of 

 quartzose sand, which is probably brought from the adjacent deserts 

 by violent winds ; 



2. That the Nile sediment found at the lowest depth reached is 

 very similar in composition to that of the present day ; 



3. That in no instance did the boring instrument strike upon the 

 solid rock, which may be presumed to form the basin between the 

 Libyan and Arabian Hills, containing the alluvium accumulated 

 through unknown ages ; 



4. That, except minute organisms discoverable only by a powerful 

 microscope, few organic remains were found, and those met with 

 were recent land shells and bones of domestic animals ; 



5. That there has not been found a trace of an extinct organic 

 body; 



6. That at the same level great varieties in the alluvium have 

 been found in adjoining pits, even when the distances between them 

 were very moderate ; 



7. That there is an absence of all lamination in the sediment. 

 The author points out the causes that account for this, chiefly the 

 rapid drying of the soil, so soon as the inundation water has sub- 

 sided, the operations of agriculture, and the violent winds that sweep 

 over the valley forming vast clouds of dust ; 



8. That in many places the disintegrations of sun-burnt bricks 

 have contributed largely to the soil ; 



9. That in nearly every part of the ground penetrated, artificial 

 substances have been found, such as fragments and particles of burnt 

 brick and pottery, and at the lowest depth reached. 



The author then enters, at some length, into the circumstances 

 which modify the deposition of the sediment in different parts of the 

 valley, showing how the coarser and heavier matter held in suspen- 

 sion in the inundation water must be deposited in greatest amount 

 in the higher parts of the river's course, in its bed, and near its 

 banks ; that this must be further caused by the slight fall, which 

 between Assouan and Cairo is less than 6 inches in a mile, the Nile 



K2 



