650 LOUIS AGASSIZ. 



ishing empire, it will be removed still further; 

 so far indeed, that I foresee the time when the 

 whole peninsula of Cape Cod shall disappear. 

 Under these circumstances, it is the duty of a 

 wise administration to estabhsh with precision 

 the rate and the extent of this destruction, 

 that the coming generations may be fore- 

 warned. In connection with this I would ad- 

 vise the making of a thorough survey of the 

 harbor, to ascertain the extent of rock sur- 

 face and of drift, and the relative position of 

 the two, with maps to show their relations to 

 the different levels of the sea, whereby the 

 unequal action of the tides upon the various 

 beaches may be estimated. 



The zoological side of the question relates 

 to the amount of loose materials accumulating 

 in consequence of the increase of animal and 

 vegetable life, especially of those microscopic 

 beings which, notwithstanding their extraor- 

 dinary minuteness, form in course of time vast 

 deposits of solid materials. Ehrenberg has 

 shown that the harbor of Wismar, on the Prus- 

 sian coast of the Baltic, is filhng, not in conse- 

 quence of the accumulation of inorganic sedi- 

 ments, but by the rapid increase and decay of 

 innumerable animalcules. To what extent such 

 deposits may accumulate has also been shown 



