No. 2.] MATTHEW — POST-PLIOCENE MOLLUSCA. 113 



though they may be, regarding the depth of the sea in which 

 these creatures lived. As I have not visited the Bay Chaleur 

 and am not informed of the exact horizon in the Post-Pliocene 

 deposit of that district, from which the shells recorded in the 

 above catalogue were taken, I am unable to say whether there 

 is a regular gradation from deep water forms in the lower beds to 

 littoral species in the higher, as in the Bay or Fundy, or not : 

 and it will be possible to speak only in general terms of their 

 bearing on the question of the depth and temperature of the sea 

 on the northern confines of Acadia during Post Pliocene time. In 

 the clay-beds of the Bay of Fundy with which I am more familiar, 

 there are proofs of a progressive shoaling of the ocean along this 

 coast during the period named. The lowest beds are a compact 

 clay, which is either red or grey, according as it is derived 

 from the red rocks of the Carboniferous area, or the grey slates, 

 &c, of the region west of it. This compact clay contains very 

 few organic remains, and these are chiefly shells of Portlandia 

 glacialis. At St. John it graduates into fine dark colored clay which 

 varies in tint from dark grey and liver-brown nearly to black, 

 according to the amount of organic matter disseminated through 

 it ; and here the shells of Portlandia glacialis abound. This 

 portion of the clay contains beds of black sand from one to three 

 inches thick, holding Ophioglypha Sarsii, Pandora glacialis, 

 Lyonsia Norvegica ? L. arenosa, Cryptodon sp. ? and other 

 shells, none of which indicate a less depth of water than that of 

 the Coralline zone. These dark beds are in turn overlaid by 

 other red clays which differ from the lower red clays in being of 

 a browner hue and having numerous intercalated beds of brown or 

 grey sand ; these clay beds while they contain Balanus crenatus, 

 Portlandia glacialis, Nucula expavsa, &c. of the lower horizon, 

 have in addition such species as Buccinum undatum, B. tenue r 

 Mya truncata, Macoma calcaria, Saxicava rugosa. A somewhat 

 shallower sea is indicated by the occurrence, at St. John, of clay 

 beds holding Mytilus edulis and Card ium pinnida turn : while a 

 still further withdrawal of the ocean is shown by the contents of 

 the sand beds which cover these clays; these appear to be the 

 equivalent of the Saxicava sand for they contain shells of Mya 

 arenaria and Macoma fusca. 



While the cnange from deep-water forms to those of the imme- 

 diate sea-shore, gives clear proof of the progressive shoaling of 

 the Post-Pliocene sea in this region, it does not show whether 



