No. 4.] DAWSON — POST-PLIOCENE. 385 



Yoldia lucida, Loven (which is abundant living in the deeper 

 parts of the Gulf of St. Lawrence) closely resembles the young, 

 smooth form of this species, but I think the two may be dis- 

 tinct. J. F. W. 



Leda {Yoldia^ lima tula .^ Say. 



Fossil — Leda clay, Riviere-du-Loup. 



Recent — Gulf St. Lawrence to Long Island. 



This shell has been found as yet only at Rivi^re-du-Loup, 

 where the specimens however are as good as those now living in 

 the Gulf. (See Figure.) It will be observed, however, that 

 though they have the number of teeth of Y. limatula, they ap- 

 proach in form to the allied species or variety Y. sapotiUa, a 

 shell which occurs in Greenland and thence to New England, and 

 which I strongly suspect is merely a short variety bearing a simi- 

 lar relation to Y. limatula to that which 3Ii/a l/ddevallensis 

 bears to the ordinary 31. truncata. Y. sapotilla is, I may men- 

 tion, the Y. Arctica of Morch, as proved by a specimen from his 

 collection now in my possession. 



Leda (^Yoldia) myalls, Couthuoy. 



Fossil — Labrador (Packard). 



Recent — Gaspe (Whiteaves) to south of Cape Cod. This 

 shell is supposed to be identical wdth N. liyperhorea, Loven, from 

 Spitzbergeu. 



Pecten Greenland icus, Chemnitz. 



Fossil — Leda clay, Portland and Saco, Maine; not yet found 

 in Canada. 



Recent — Gulf St. Lawrence (Whiteaves) in deep water 200 

 to 300 fathoms. 



This species is found in the Clyde beds and in Greenland ; and 

 if, as Jeffreys supposes, identical with F. similis (Laskey), it is 

 a shell of very wide distribution in the Atlantic, as well as iu 

 geological time. Though not yet found in Canada as a Post- 

 pliocene fossil, its occurrence as a fossil in Maine and recent in the 

 Gulf St. Lawrence, renders it probable that it may yet occur in 

 our Leda clays. 



Pecten tenuicostatus, Mi<ji;hels. 



Fossil — Leda clay, St. John, N.B. (Matthew). 



Recent — Labrador to Cape Cod. 



This shell has not yet been found in the Post-pliocene of the 

 Vol. VL r No. 4. 



