78 THE AMERICAN MONTHLY [Mar., 



have sometimes noticed living specimens of large size and 

 peculiar structure, whose make-up caused me to suspect 

 that certain forms illustrated in the books and classed in 

 different genera were merely different |»arts of the same 

 organism, but circumstances prevented the thorough in- 

 vestigation necessary to demonstrate the facts, and I 

 therefore mention it merely as a suspicion. Atthe eas- 

 tern end of Leete's Bay is " Shell Beach " extending* from 

 the main land to Leete's Island, and crossing the ancient 

 channel which once surrounded the Island ; this beach 

 has a local celebrity on account of the number and va- 

 riety of the shells cast up by the tide ; among these are 

 many species of small round clams, one of these averages 

 about the size of a common cherry stone. A larger spe- 

 cies has a bright pink color and very thin shell. The 

 razor shell or Solen, K. (^usis is numerous in all sizes, and 

 Fnlgar car/ca and F. canalioidatus are plentiful, Mart.v, 

 Helix, Helicina, Zonites, Nassa and other genera with 

 P'enrotoiha 7niriinia and Littorina ohtnaata abound. Af- 

 ter the st(>rm, living s]iecimens which had the form and 

 outline of Lrda fiotoerhya/ta, but which did not gaj) at 

 extremities and had the polished surface of Leda corpid- 

 onta were left upon the beach. The row of minute sharp 

 pointed teeth possessed by these shells is a peculiar fea- 

 ture of their structure. Near tlie point of the island and 

 on the north shore of (Ireat Harbor, I picked up two or 

 three dozen of the rare sliells of Pdudora ei^ylon'tea. 



Shell Beach is being slowly driven inland by the sea ; 

 its recession is laying bare deposits laid down many 

 years ago, the diatoms of these deposits are much like 

 those of the soundings. I lind them difficult to clean on 

 account of the (]uantity of minute scales of mica tiiey 

 contain, which are almost impossible to separate by or- 

 dinary methods. I have made a few slides by separat- 

 ing the heavier discoid forms by the process first pointed 

 out by Christopher Johnston, M. D., in The Lens of No- 



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