106 



1. Coal brook. 



2. Omineca river. 



3. Finlay river. 



4. Blackwater river. 



5. Kamloops 



6. Tranqnille river. 



COAL BROOK. 



As already shown, Coal brook lies within the Indian reserve on the North Thompson 

 river, and belongs to a very small area of Tertiary formation constituting an outlier widely 

 separated from the main group of deposits, and according to the opinion of Sir William 

 Dawson, already quoted, the formation may be of somewhat more recent age than the 

 Laramie of the plains. 



The very scanty jflora so far collected, embraces the following representatives : — 



1 . Populus arctica. 



2. genetrix. 



3. subrotunda. 



4. Pyrus sp. 



5. Rhus roscefolia ? 



6. Thuya interrupla. 



7. XJlmus sp. 



Of these seven forms we may at once eliminate Ulmus sp and Pyrus sp. as of no value, 

 and the same may also be said of Rhus roscefolia, since the specific form in this case is 

 inferred rather than proved. We, therefore, have only four constituents of the flora upon 

 which to place reliance. 



Populus arctica is a species well known to both the Eocene and Miocene of the United 

 States and Canada, and Knowltoni states that it is abundant from the Laramie to the Miocene, 

 or throughout the Tertiary. It is obvious that such a general type can have but little value 

 as a factor in determining age. 



Populus genetrix has been found at Red Deer river and also at Quilchena, but in the 

 United States it is wholly confined to the Fort Union group, and its aspect is, therefore, 

 decidedly Eocene or Lignite Tertiary. 



Populus subrotunda in Canada is altogether confined to Coal brook, while in the United 

 States it is wholly confined to the Laramie of Carbon and Evanston, Wyoming, and localities 

 of equivalent horizon. 



Thuya interrupta is known at Porcupine creek, but it also occurs in the Miocene ? of 

 Nine-mile creek and at Quilchena. In the United States, on the other hand, it is wholly 

 confined to the Fort Union group. 



From the facts thus brought forward it appears that all three species are well known 

 constituents of the Lignite Tertiary. Hat a,s Populus genetrix belongs to the beds in question 



1 Cat. Cret. and Tert. Plants, U.S. Geol. Surv., Bull. 152, 1898. 



