MR. HORNER'S EGYPTIAN RESEARCHES. 395 



have been altogether deposited in the last few hundred years, 

 i.e. since the embankments have been neglected, the thickness 

 of the deposit will still be a measure of the general elevation 

 which has taken place on the surrounding plain since the 

 erection of the monument. 



Even if the embankments had remained intact to this day, 

 and the monument stood now in the hollow thus produced, 

 Mr. Horner's argument would not be invalidated, but rather 

 confirmed. The depth of the hollow would give us a measure 

 of the deposit which had taken place since the erection of the 

 monument, or rather since the formation of the embankment. 

 If, however, the monument had been erected in an area already 

 depressed by the action of still older embankments, the calcu- 

 lation would be vitiated, but in this case the rate of deposition 

 would appear to be greater than it really is, and the true age 

 consequently would be even greater than the above estimate. 

 There are other causes, however, whick prevent me from 

 accepting unreservedly the conclusions of Mr. Homer, although 

 his experiments are of great importance, and much credit is 

 due to the Egyptian Government for the liberal manner in 

 which they assisted Mr. Horner and the Koyal Society in this 

 investigation. 



I have already mentioned the evidence on which M. Moiiot 

 has endeavoured to estimate the age of the Cone de la Tiniere, 

 and which gave about six thousand years for the lower layer 

 of vegetable soil, and ten thousand years for the whole of the 

 existing cone. But above this existing cone is another, which 

 was formed when the lake stood at a higher level than at 

 present, and which M. Moiiot refers to the period of the river- 

 drift gravels. This drift-age cone is about twelve times as 

 large as that now forming, and would appear, therefore, on 

 the same data, to indicate an antiquity of more than one hun- 

 dred thousand years. 



In his " Travels in North America," Sir C. Lyell has endea- 



