CHAPTER III. 



PHYSICAL AND CLIMATAL CONDITIONS. 



/. — Geyieral Conditions. 



It is, I think, universally admitted that the later 

 Pliocene age, immediately preceding that of the boulder- 

 clay, was a period of elevation of the continents in the 

 northern hemisphere, the "first continental period" of 

 Lyell. The evidences of this are to be found in every 

 text-book of geology, and in Canada I may refer to the 

 excavation of the Saguenay valley, as explained by me 





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wr 



W^:^ 



Fig. 4. — Valley of Lower Saguenay— Old glacier bed. 



in my notes of 1872, referred to below, and to the similar 

 evidence accumulated by Dr. G. M. Dawson regarding the 

 cafions of British Columbia.* It has also been conclu- 



* See also Upham, Geol. Magazine, Nov., 1890, and Bui. Geol. 

 Society Am., Vol. I.; Spencer, lb., May, 1890; and Journal Geol. 

 Society, Nov., 1890. 



