LIFE ON THE EARTH. 139 



directly apply to the land of Egypt. The statement 

 is to the effect that if the Mle were turned into the 

 Arabian gulf, that part of the sea would be filled 

 up by sediments in 20,000 years ; indeed, according 

 to his own opinion, in 10,000 years. Such being the 

 present tendency of the river to deposit sediment, 

 he justly concluded that, in the long lapse of earlier 

 time, the Nile may have filled up the greater Egyp- 

 tian gulf which lay in its course. 



De Luc, one of the most ingenious and labo- 

 rious geologists at the close of the last century and 

 the commencement of the present, devoted much 

 attention to those operations of the sea and rivers 

 which promised to afford some measures of effect 

 applicable to the problems of past time. The growth 

 of new land on the sea-shore, the waste of the old 

 surfaces by the waves, the filling up of lakes and the 

 wearing away of valleys, these, diligently studied, 

 led him to the general conclusion that the actual 

 state of our continents is not ancient ; that it is 

 not very long since they were given to the dominion 

 of men ; that not many ages have elapsed since the 

 continental parts of our globe were abandoned by 

 the ocean. 



The limited growth of new lands still yearly on 

 the increase by deposition of sediment the small 

 extent to which lakes have been filled up by the 



