No. 4.] DAWSON — POST-TLIOCENE. 381 



Cardlum Islandicum, Linn. 



Fossil — Riviere-du-Loup ; Murray Bay ; Saguenay ; Portland, 

 Maine; Lawlor's Lake, N.B. ; Greenland, Moller). 



Recent — From Greenland to New England. 



Our fossil specimens are mostly small, and similar to the 

 northern variety or sub-species named by Stimpson C. Hayseii, 

 and which also occurs living as far south as Nova Scotia, and 

 seems to be the C. ciliatum of Fabricius. Decorticated speci- 

 mens are not distinguishable from C. Daivsonii of Stimpson, from 

 the Post-pliocene of Hudson's Bay ; of which I have seen only 

 specimens in this state. 



Serripes Grcenlandica, Chemnitz. 



Fossil — Leda clay, and Boulder clay, Quebec ; Rivi^re-du- 

 Loup; Murray Bay; Lawlor's Lake, N.B. ; Cape Elizabeth, 

 Maine; Labrador, (Packard) ; Greenland (Moller). 



Recent — Gulf St. Lawrence, sometimes of large size, Arctic 

 seas, and Greenland to Cape Cod. 



This shell is somewhat rare and of small size in the Post-plio- 

 cene, and has not yet been found higher up the St. Lawrence 

 than Quebec. Specimens of good size occur at Portland. 



Cryptodon Goiddii^ Philippi. 



Fossil — Montreal, rare. 



Recent — Murray Bay ; Gasp^ (Whiteaves) ; Greenland to 

 New England. 



The European form C. flexuosa is usually regarded as distinct, 

 and is found as far north as Spitzbergen, and in the Crag, the 

 Clyde beds, and the Norway Post-pliocene. Jeifreys, however, 

 considers the difference merely varietal, and it certainly seems to 

 diminish or disappear in the northern and glacial specimens. 



According to Mr. Whiteaves this species has a great range in 

 depth in the Gulf St. Lawrence, being found, living, from 20 

 to 300 fathoms. 



Spliaerium ? 



Fossil — Pakenham Mills, with fresh-water bivalves and Tellina 

 Groenlundica. The specimens were too imperfect for certain 

 determination. 



Uii'lo rectus, Lamarck. 



Fossil — Clarenceville, Lake Champlain (Dickson), with Mya 

 arenaria, Tellina Qrcenlandica, &c. 

 Recent — River St. Lawrence. 



