166 On the Mollusca of Long Island. 



I subjoin a table giving tbe formations in which the shells 

 occur as fossils, as well as the Geographical Range of the living 

 shell. In this I have included all the other shells which are 

 found from Stonington to Cape Cod ; so as to comprise in it 

 all the species of the extreme north of the Atlantic Molluscan 

 Province. This table is of course very far from being complete, 

 but may serve to give an idea of the Geographical and Geolo- 

 gical relations of the Fauna. The principal authorities em- 

 ployed have been " Forbes on the Geological Relations of the 

 Existing Fauna and Flora of the British Isles," Mr. McAndrew's 

 reports on dredging, Dawson & Lyell's papers on the Canadian 

 Glacial beds, Mr. Bell's catalogue of the shells of Canada, 

 Stimpson's " Shells of New England," Lyell's papers on Ameri- 

 can Miocene deposits, Tuomey & Holmes' Post Pliocene Fossils 

 ofSouthCarolina,Tuomey's Geological Report on South Carolina, 

 Mr. Kurtz's list of the shells of North and South Carolina, and 

 many of Conrad's papers in Silliman's Journal, and the Journal 

 of the Academy of Natural Sciences of Philadelphia. 



Eleven species occur in the Post Pliocene of Florida, all 

 except one of which are already known to exist as far south, or 

 may probablj' be foijnd there hereafter. Myt'ilus edulis is marked 

 by Conrad as fossil from St. John's River, Fl., but does not 

 occur in Kurtz's list of N. Carolina and S. Carolina shells. 



Thirty-nine species occur in the Post Pliocene of South Caro- 

 lina, three of which, Leda limatula, Thraoia trunoata^ and 

 Natica heros^ I can find no mention of as recent shells so far 

 south, whilst Cardmin Mortoni^ though said by Conrad to be 

 abundant in Florida, does not occur in Kurtz's N. C. and S. C. 

 lists, and is considered by Tuomey & Holmes as probably fossil 

 only in South Carolina. 



Yermctus radicula is fossil in North Carolina, and recent in 

 Florida, and Cytherea convexa is fossil in N. Carolina, and 

 though occurring in Kurtz's recent list, is marked there as very 

 probably fossil only. 



In the Glacial Beds of Canada seventeen species occur, in- 



