THE HARBOR OF BOSTON. 651 



by Ehrenberg, who ascertained, many years 

 ago, that the city of Berlin rests upon a de- 

 posit of about eighteen feet in thickness, con- 

 sisting almost exclusively of the solid parts 

 of such microscopic beings. These two cases 

 may suffice to show how important may be a 

 zoological investigation of the harbor de- 



o o 



posits. 



I need hardly add that the deposits floated 

 into the harbor, by the numerous rivers and 

 creeks which empty into it, ought to be inves- 

 tigated with the same care and minuteness as 

 the drift materials. This investigation should 

 also include the drainage of the city. 



But this is only a smaU part of the applica- 

 tion I would recommend to be made of geo- 

 logical and zoological knowledge, to the pur- 

 poses of the Coast Survey. The reefs of 

 Florida are of the deepest interest, and the 

 mere geodetic and hydrographic surveys of 

 their whole range would be far from exhaust- 

 ing the subject. It is my deliberate opinion 

 that the great reefs of Florida should be ex- 

 plored with as much minuteness and fullness 

 as the Gulf Stream, and that the investiga- 

 tion will require as much labor as has thus 

 far been bestowed on the Gulf Stream. Here 

 again geological and zoological knowledge is 



