REVIEWS. 



23; 



This is followed by a general view of the entire series of deposits 

 of eastern Canada and a discussion of these, in the course of which he 

 states the views of the origin of the deposits which are set forth more 

 fully in a subsequent part of the book. In the course of the chapter 

 he presents a scheme of correlation of the phenomena of the glacial 

 period in the Cordilleran region conjointly with those of the region of 

 the great plains (in ascending order), in which epeirogenic movements 

 constitute the leading feature. The following is an abbreviation : 



Cordilleran Region. 

 Cordilleran zone at a high elevation ; 

 severe glaciation ; maximum develop- 

 ment of Cordilleran glacier. 



Gradual subsidence of Cordilleran re- 

 gion ; boulder clay of interior plateau and 

 Yukon basin ; lower boulder clay of coast 

 region; interglacial silty beds at later stage. 



Re-elevation of Cordilleran region ; 

 maximum of second glaciation. 



Partial subsidence Cordilleran region ; 

 formation of white silts ; upper boulder 

 clay of coast region, probably. 



Renewed elevation of Cordilleran 

 region ; general amelioration, closing gla- 

 cial period. 



Region of the Great Plains. 



Correlative subsidence and submergence 

 of the great plains with possible contem- 

 poraneous elevation of Laurentian axis 

 and maximum development of the ice 

 upon it. 



Correlative elevation of western part of 

 great plains, probably irregular ; forma- 

 tion of extensive lakes ; interglacial de- 

 posits, including peat beds. 



Correlative subsidence of plains ; sub- 

 mergence to base of Rocky Mountains ; 

 formation second bovilder clay. 



Correlative elevation of plains, proba- 

 ble formation of Missouri Coteau along 

 shore line. 



Simultaneous elevation of great plains 

 to present levels ; exclusion of the sea ; 

 formation of Lake Agassiz ; gradation 

 into present period. 



Sir William Dawson would make three subdivisions of the Pleistocene 

 period embracing (c?) ^a;r//(?r jP/m/^^^;z."; irregular depression of the 

 ■continents, with cold climate and great local glaciers ; {f) Middle 

 Fleistocene ; submergence of coasts and re-elevation of interior plateaus, 

 with milder climate — interglacial period; and {c) Latci- Pleistocene ; 

 submergence of plains and general ice drift with local glaciers in moun- 

 tains. The succeeding thirty pages of the chapter are devoted to the 

 description of the deposits. 



The third chapter is devoted to physical and climatal conditions. 

 In the course of this the author introduces a map to show the distribu- 

 tion of glaciated and unglaciated land, and of ice-laden and of ice-free 



