150 



" Numerous volcanic flows are now represented by dikes, and in their neighbourliood the 

 beds are rouglily brecciated. Many of these volcanic outcrops v^ere produced prior to the 

 glacial period." 



In the following year the same author made the following statement : — 



" Further and more detailed examination of the portion included in the Kamloops map 

 sheet still fails to afford the necessary palseontological data for any complete subdivision 

 of the Tertiary rocks. However, it is evident that the rocks collectively referred to as Tertiary 

 represent a very long period of time, with several changes of condition, and that there are 

 also probably one or more gaps^ unrepresented so far as known by deposits of any kind. 

 These general facts are established chiefly by stratigraphical and other physical characteristics 

 and relations of the rocks, but they are borne out also, in a measure, by the slight evidence 

 to be obtained from fossils. These consist almost exclusively of plant and insect remains, 

 obtained from several localities, of which one of the most striking peculiarities is the diversity 

 of each collection from the others."' 



GEXEEAL SUMMARY AND CONCLUSIONS. 



From the evidence presented in the foregoing pages it is evident that the Tertiary forma- 

 tion of British Columbia, as at present known, cannot be regarded as more recent than Lower 

 Miocene, and that the greater portion of the beds is of Oligocene age. Upon this point 

 Sir William Dawson^ has already observed that "some of the plants enumerated may be 

 Eocene, but the Similkameen flora is Lower Miocene or Oligocene. It is closely allied to the 

 Green River and Florissant floras which Lesquereux regards as Oligocene or Upper Eocene." 

 It is further evident, however, that these beds are superimposed in part, perhaps for their 

 entire extent, upon older Tertiary strata which are of Lower Eocene or Fort Union age, and 

 which immediately overlie the Cretaceous strata. These beds undoubtedly extended as far east 

 as Turtle mountain in Manitoba, but eventually the eastern section lying in Manitoba,Saskatche- 

 wan. Alberta and the more northern districts of the Mackenzie river,was separated Trom the west- 

 ern areas by the great uplift of the Rocky mountains which was brought about in Miocene time. 

 Whether there were any Miocene deposits to the eastward of the mountains does not appear from 

 the evidence at hand, butit is a fair presumption that the Oligocene was represented there asit 

 how is farther west. In such case this formation must have been removed by the extensive 

 erosion to which the eastern areas have been subjected, or the beds are yet to be found in the 

 upper portions of those towering buttes which give such striking character to the region; and 

 in the base of which lignite beds are found. 



It only remains to present a review of the general evidence upon which the position of 

 the earlier Tertiary beds is recognized as Upper Laramie, Fort Union or Lignite Tertiary. 



Referring to the Central Plateau of Saskatchewan and Alberta Dr. G. M. Dawson 

 employs the following description : — 



" The steppes of this great slope may be naturally divided into three groups having 

 different ages and circumstances of deposition, and boldly marking three distinct prairie 



1 Kamloops Map Sheet. Geol. Surv. Can., 1877-78, 112 B. 



2 Trans. R.S.C., VIII, 1890, iv, 90. 



