138 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 

 POST-PLIOCENE GEOLOGY OF CANADA. 



Dr. J. W. Dawson has recently published an exhaustive 

 paper upon the post-pliocene geology of Canada, in which he 

 enumerates all the species of animals and plants hitherto de- 

 tected in that formation. His list embraces ten species of 

 plants, one hundred and ninety of invertebrates, and five of 

 vertebrates two hundred and five in all. The whole of 

 these, with three or four exceptions, are living northern or 

 arctic species, the marine species belonging to moderate 

 depths, reaching down to about two hundred fathoms. The 

 assemblage is identical with that of the northern part of the 

 Gulf of St. Lawrence and Labrador coast at present, and dif- 

 fers merely in the presence or absence of a few more south- 

 ern forms, now occurring in the Gulf; especially in the south- 

 ern part, where the fauna is of a New England type, whereas 

 that of the post-pliocene may be characterized as Labrado- 

 rian. As might have been anticipated from the relations of 

 the modern marine fauna, the species of the Canadian post- 

 pliocene are in great part identical with those of the Green- 

 land seas and of Scandinavia, where, however, there are many 

 species not found in our post-pliocene. The post-pliocene 

 fauna of Canada is still more closely allied to that of the de- 

 posits of similar age in Britain and in Norway, change of 

 climate having been much more extensive on the east than 

 on the west side of the Atlantic, owing to the distribution 

 of warm and cold currents, resulting from the present eleva- 

 tion of the land. 



The amelioration of the climate seems to have kept pace 

 with the gradual elevation of the land, which threw the cold 

 ice-bearing arctic currents from its surface, and exposed a 

 larger area of land to the action of solar heat, and also prob- 

 ably determined the flow of the waters of the Gulf Stream 

 into the North Atlantic. By these causes the summer heat 

 w r as increased, the winds, both from the land and sea, were 

 raised in temperature, and the heavy northern ice was led 

 out into the Atlantic, to be melted by the Gulf Stream, in- 

 stead of being drifted to the southwest over the lower levels 

 of the continent. Still the cold arctic currents entering by 

 the Straits of Belleisle, and the accumulation of snow and 

 ice in winter, are sufficient to enable the old arctic fauna to 



