3 2 The Founders of Geology LECT. 



is borne away seawards, and gradually settles down on the 

 sea-floor. As the nature of the part so transported must 

 depend on that of the material on the shore, he is led to 

 enter upon a minute examination of the mineral constitu- 

 tion of the coast-lines of France, both on the Atlantic and 

 Mediterranean margins of the country. 1 



He recognizes that soluble substances may be carried 

 for great distances from the land, and may remain dissolved 

 in the sea-water for a very long time. He even conjectures 

 that it is possibly these substances that impart its salinity 

 to sea- water. 2 



From all the soundings available in his day, he con- 

 cludes that the bottom of the sea is, throughout its whole 

 extent, covered mostly with sand, which is probably not 

 derived from the detritus of rivers. 3 He observes, regard- 

 ing this widely-diffused deposit, that it might be thought 

 to be due to the grinding down of submarine rocks by the 

 sea itself. But he contends that " how violent soever may 

 be the movements of the sea, they can have but little effect, 

 save on those rocks which emerge above the level of the 

 water, the greatest storms being little felt except on the 

 surface, and for a short way below it." In this sagacious 

 and generally accurate inference, however, he was long 

 before anticipated by Boyle. 



Considering, further, the problem presented by the 

 general diffusion of sand over the bed of the sea, he thinks 

 that the erosive influence of the ocean cannot be enough 

 to account for this deposit, which is spread over so vast an 

 area. He concludes, therefore, that the sand must date 

 back to the remote ages of the destruction of the mountains. 



1 P. 328. 2 P. 360. 3 P. 401. 



