2 GEORGE V. SESSIONAL PAPER No. 25a A. 1912 



CHAPTER XVI. 



FORMATIONS OF THE OKANAGAN RANGE AND OF KRUGER 

 MOUNTAIN PLATEAU. 



From the eastern slope of the wide valley occupied by Osoyoos lake to the 

 Pasayten river, a distance of just sixty miles along the Boundary, the mountains 

 are composed of almost continuous plutonic rocks. (Maps No. 12 and 13). This 

 strip of generally rather rugged mountains forms part of a huge batholithic area 

 of heterogeneous rocks which will be adequately mapped only after many more 

 seasons of arduous field-work. The geological findings within such a belt as 

 now to be described would be much increased in value if they could be syste- 

 matically compared with field studies throughout the whole batholithic province. 

 For many reasons such a complete survey is now impracticable. The present 

 chapter is thus a sort of a report of progress on the geology of these crystalline 

 rocks of the northern Cascades. Nevertheless discoveries of prime importance 

 to the geology of the entire range have been made within even the limited area 

 of the five-mile belt. Certain of the broader conclusions there deduced may., it 

 is believed, be relied on, and will not need serious emendation as the exploration 

 cf the mountains continues. In the following pages there is offered another 

 class of considerations which are theoretical and need the facts of the field, 

 especially of the whole Cascade field, for their full discussion. In these matters 

 particularly, a five-mile belt can not speak for the whole Okanagan range, 

 except as geological experience in that belt accords with verified geological 

 experience the world over. 



General Description of the Batholithic Area. 



To simplify the following discussion it will be well to review the general 

 geographical relations among the different geological units. To the same end it 

 is convenient to adopt a special name for each unit. The cross-section, Figure 

 27, shows the units in their relative positions. 



The most easterly component body occupies both slopes of Osoyoos Lake 

 valley; it is the southern part of a great batholithic mass of granodiorite and 

 may be called the Osoyoos batholith. The most westerly unit extends from 

 Pasayten river to within a mile or so of Cathedral Peak. It is also a batholith 

 of granodiorite and seems to compose the cliffs of the conspicuous Mount 

 Remmel, five miles south of the Boundary. This mass may be called the 

 Remmel batholith. Immediately to the eastward of the Remmel a third large 

 batholith, this time composed of a quite different rock, true biotite granite,. 



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