CHAPTER XL 

 THE ROCKS OF THE JOHN DAY VALLEY. 



[ Published in The Overland Monthly, May, 1871.] 



In the controversies of the day on the 

 Origin of Species, any record of the past 

 as authoritative as that of a good geological 

 field, covering an extensive range and filled 

 with minute details of events, can hardly fail 

 to be instructive. The basin of the Columbia 

 river, with its tributaries, offers such a history 

 to the world at once continuous and author- 

 itative, reaching, in its field of operations from 

 the Rocky mountains to the Pacific ocean, 

 and, in the time it covers, from the Cretaceous 

 period to the recent. It covers even the lay- 

 ing of the foundations of the country and de- 

 fines the narrow strips of land that first 

 emerged from the ocean to become the frame 

 work of the great mountain chains. Later, 



