CONCHOLOGT. 



The following is a copy of the communication of Professor 

 Chester Dewey, of Rochester, accompanying his donation of 

 fresh-water shells, furnished to the State Cabinet. 



*' To John Gebhard junior, 



Curator of the State Cabinet of Natural History. 



I direct to your hand, the shells collected chiefly in this section of the 

 State, for the State Cabinet. They belong to the family Naiades, usually 

 called clams or mussels, and are named accprding to the synopsis of Isaac 

 Lea, Esq. Not all those described in the State Natural History, by Dr. 

 Dekay, have yet been found here; but some others, not before credited 

 to the State, by any writer that I have seen, are put into the collection. 



I have sent twelve species of Unio from this section, and have added 

 seventeen species, chiefly from Ohio; three species of Margaritana of 

 Schumacher^ usually called Alasmodonta ; and eleven species of Anodonta. 



Alasmodonta arcuata, Barnes, has not occured to me in this part of 

 the State. 



While most of the species are abundant, some inhabit deep water, and 

 are difficult of access. Two species, TJnio alatus, and TJnio complanaUis, 

 are in vast numbers between the lake (Ontario) and the first falls of the 

 Cenesee river, for the distance of four miles or more. I have brought up 

 by a rake fourteen inches by four, from three to fourteen specimens. The 

 bottom of the river, ten or fifteen rods broad, seems full of them. Indeed, 

 a man who has often dived and examined the bottom of the Genesee in 

 various places on the level of the lake, asserts that the bottom is literally 

 covered with these shells. If they are as numerous in the whole breadth 

 as I have found them in many places for a mile or two, there must be 

 many thousands of bushels. TJnio luteolus, is also abundant. To those, 

 who have made more explorations, this mass of fresh-water clams may 

 not be surprising ; but it far surpassed all my anticipations. As these 

 species have thick and strong shells, the muskrats, which devour clams, 



