GEOLOGICAL RELATIONS 357 



are comparable in age to quite similar formations forming the eastern 

 limit of the Okanagan Composite batholith as a whole. From the eastern 

 contact of the Osoyoos batholith eastward for nearly 20 miles the rolling 

 mountain slopes are chiefly underlain by an intensely folded, mashed, 

 and metamorphosed group of quartzites and phyllites, in which there 

 occur intercalations of ancient diabasic rocks with occasionally strong 

 pods of semi-crystalline limestone. These rocks had been crushed and 

 dynamically metamorphosed before the intrusion of the oldest component 

 batholith of the Okanagan range. Again and again since that early 

 period of metamorphism the same stratified formations have been gripped 

 in the writhing paroxysms of Cordilleran revolutions. So extensive has 

 been the crumpling, shearing, and overturning that it must ever remain a 

 matter of the utmost difficulty to reduce the series to stratigraphic order. 

 Within the belt covered by the Boundary Commission it has proved so far 

 impossible to secure either a bottom or top to the series. Fossils entirely 

 fail. All that can be said concerning the age of the metamorphosed sedi- 

 ments is that they are almost certainly Paleozoic. In many respects they 

 have lithological characters like those of Carboniferous formations both 

 in California and British Columbia. It is very possible that portions of 

 the series are still older. From analogies drawn from better known re- 

 gions in the Cordillera, it is believed that the basic intrusives of mount 

 Chopaka and of the great schist-sediment area east of Osoyoos lake are 

 likewise of Paleozoic age, though of course younger than the schists and 

 quartzites which they cut. 



Since the rocks of the Basic complex are crushed and metamorphosed 

 in as extraordinary degree as any of the above-mentioned formations, the 

 complex is regarded as a Paleozoic parallel to the Chopaka basic intru- 

 sives, though perhaps not strictly contemporaneous with the latter. For 

 a reason already noted, the Ashnola gabbro is possibly to be correlated in 

 age with the larger part of the Basic complex. 



The mode of intrusion and therewith the structural relation of each of 

 these basic masses to its original country rock can not be declared. In the 

 case of two of them — the Basic complex and the Ashnola gabbro — not a 

 fragment of the invaded formation has been found. It is, however, im- 

 probable that any of these bodies ever had batholithic dimensions. Their 

 present isolated positions and the analogy of other similar gabbro-perido- 

 tite bodies in the Cordillera suggest that each of them was of relatively 

 small size. The Chopaka body cross-cuts the bedding of the quartzites 

 and schists. It may be in "chonolithie" relation to these — that is, it may 

 be an irregularly shaped mass magmatically injected into the bedded 

 rocks, but not, as with a true laccolith, following bedding planes.* The 



*Cf. Journal of Geology, vol. xiii, 1905, p. 498. 



