HISTORICAL NOTICES. 3 



reaction to better views has begun to set in, and that 

 geologists are more disposed than formerly to restrict 

 their speculations within the limits of physical possibility. 

 We shall see evidence of this in the sequel ; but before 

 referring to the conclusions of others, I may be pardoned 

 for giving a sketch of the progress of opinion, as it has 

 presented itself in connection with my own work. 



When I first entered on the study of these deposits in 

 Nova Scotia, in the year 1841 and subsequent years, my 

 guide and instructor was the great apostle of moderate 

 uniformitarianism, that is, of rational geology, Sir Charles 

 Lyell. His views as to the combined agency of land ice 

 or glaciers, of floating fragments of glaciers or ice-bergs, 

 and of field ice, are, or ought to be, well known ; but ~I 

 must say that they have often been unfairly stated. 

 Lyell well knew the nature and work of glaciers in so 

 far as ascertained in his time. He had also collected a 

 large amount of information as to the conveyance of 

 boulders, etc., by ice-bergs, and the formation of subma- 

 rine glacial deposits thereby. Lastly, he had profited by 

 the observations of the Arctic voyagers, and by those of 

 Bayfield in the river Saint Lawrence, so as to appreciate 

 the great carrying and erosive power of heavy field ice. 

 His general theory of the glacial age was based on all 

 these factors, along with the gradual depression and re- 

 elevation of the continents in the pleistocene period. I 

 confess that I still adhere to his views in these respects, 

 with only such modification as to the relative value of 

 particular and local causes, as the observations and reading 

 of fifty years have necessitated. 



My own conclusions with reference to the phenomena 

 observed in the Maritime Provinces of Canada, were ex- 

 pressed for the first time in the first edition of "Acadian 



