20G 



THE OCEAN. 



form of the dunes is obliterated, it is evidently because two or more 

 hillocks have been united, and, so to say, amalgamated by the im- 



Fig. 92.— Cresceut-shaped Dunes. 



petuous wind which blows from the sea. However, we can account 

 to ourselves for all these phenomena by studying the little swellings 

 of sand, or miniature dunes, which are formed in thousands on the 

 marine shores. 



