collected by Capt. Bayfield in Canada. 139 



dredged up at Bic, in the same state as the Beauport fossils, but none of those 

 sent to me were in the state of recent shells. 



The newer Pliocene fossils therefore of Canada, so far as they have been hitherto 

 examined, belong to species which either range in a living state from the Gulf of 

 St. Lawrence to the borders of the north polar circle, or are now only known in 

 high northern latitudes, as in the seas of Greenland, Iceland, and Norway, or agree 

 with varieties or species found in the newer Pliocene deposits of Scotland and 

 Sweden. On the other hand, many of the living species of shells now most con- 

 spicuous from their size or abundance in the Gulf of St. Lawrence are wanting in 

 the collection of fossils hitherto obtained, as for example, Mactra solidissima, Me- 

 sodesma Jauresii, Purpura Lapillus,va.r., Natica Heros, Rostellaria occidentalism and 

 several others. 



It would doubtless be rash to insist positively on any general conclusions which 

 we may be tempted to draw from so small a number of fossil shells as those hitherto 

 procured in Canada, but judging from them alone, they approach more nearly to 

 the fossils of the most modern deposits of northern Europe than do the actual 

 faunas of Europe and America in corresponding latitudes. The number of testacea 

 indeed hitherto regarded as common to the opposite sides of the Atlantic is very 

 small. Eleven only were known to Dr. Beck in 1836, and Mr. George Sowerby 

 was able to add no more than four or five after a recent comparison of a large col- 

 lection of shells of North America with those of Europe ; and the fifty-two recent 

 shells obtained by Capt. Bayfield from the St. Lawrence have only contributed one 

 more to the number, namely, Cardium islandicum, which inhabits the northern 

 parts of the German Ocean, Capt. Bayfield informs me that he also discovered 

 the Cardium islandicum fossil at Port Neuf, although in too disintegrated a state 

 to be preserved. 



As the climate of Canada is now excessive, it is natural that we should find in 

 the Gulf of St. Lawrence many northern and arctic species, and no mixture of tro- 

 pical forms, for these last cannot resist severe cold, although we know from the 

 analogy of the southern hemisphere that they can extend far toward polar lati- 

 tudes, dispensing with a high temperature in summer provided the winters be mild. 



It is very probable, therefore, that in the period immediately antecedent to the 

 present the climate of Canada was even more excessive than it is now, and that 

 the shells resembled still more closely that small assemblage now found in high 

 northern latitudes. This extreme cold may have coincided with the era of the 

 principal transportation of erratic blocks, which have reached the 36° 30' degree 

 of latitude in North America*. 

 * Darwin, Journal of Travels in South America, in Voyage of H. M. S. Beagle, Appendix, p. 614, 



who cites Rogers. 



t2 



