^82 THE CANADIAN NATURALIST. [Vol. vi; 



Unio Cardium ? Rafinesque. 



Fossil — With the preceding. This and the precediilg species 

 were represented by large and thick shells better developed than 

 those of the River St. Lawrence at present. It is probably, the 

 same with U. ventricosus, Say. 



Mytilus edulis Linn. 



Fossil — Montreal ; Acton ; Riviere-du-Loup ; Quebec ; La- 

 brador (Packard) ; Lawlor's Lake, N.B. (Matthew) ; Green- 

 land (Moller). 



Recent — North Atlantic and Arctic seas generally ; North 

 Pacific (= trossiclus, Gould) as far south as Monterey. 



The variety most commonly found in the Post-pliocene is a 

 small, oval, tumid form, allied to variety elegans of British 

 writers (see figure). This variety still lives at Tadoussac ; and 

 is apparently characteristic of situations where the water is cold 

 and exposed to intermixture of fresh water. The ordinary variety 

 occurs at Portland, and also in some of the upper beds at Riviere- 

 du-Loup. At Montreal only the small oval variety occurs. This 

 variety is also found in the Clyde beds and in the crag. 



Modiola tnodiolus^ Linn . 

 Fossil — Montreal, very rare- 

 Recent — Labrador to New England; very common on the 

 coasts of Nova Scotia and New England ; North Pacific ; found 

 sparingly along the Vancouver and Californian coasts till it is 

 replaced in the Gulf fauna by M. capax, Conrad. 



This species becomes rare to the northward ; and this, as well 

 as its being proper to rocky shores rather than to clays and sands, 

 may account for its rarity in the Canadian Post-pliocene. It is, 

 however, common in the glacial beds of Europe. 



Modiolaria Qiigra, Gray. 



Fossil — Montreal ; Riviere-du-Loup (small variety nexa ; 

 also large and fine) ; very large and well preserved in nodules at 

 Kenuebeck, Maine ; Labrador (Packard of his 3f. discrepans as 

 I suppose.) 



Recent — Gulf of St. Lawrence (Whiteaves). Very large and 

 fine on coast of Nova Scotia (Willis), and as far north as Green- 

 land {M. discors, Fabricius). 



ModioJaria corrugata, Stimpson. 

 Fossil — Riviere-du-Loup. 



