<468 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



i>atholith and {he fair accordance in trends of the zones occurring in both batho- 

 liths suggest /hat there has been but one such revolutionary disturbance since 

 the batholith were irrupted. If this be true, the period is identical with the 

 post-Lower Cretaceous epoch, when the Pasayten Lower Cretaceous was thor- 

 oughly foldel and crushed into its present greatly deformed condition in the 

 Hozomeen range. 



The Ojoyoos and Eemmel batholiths are thus probably contemporaneous; 

 probably both are post-Carboniferous and certainly pre-Qretaceous. It is best 

 to correlate them with similarly huge bodies of granodiorite determined as 

 Jurassic in California and southern British Columbia. 



It should be noted that, since the Eemmel granodiorite disappears under 

 the cover of lower Cretaceous at the Pasayten, sixty miles is the minimum 

 width of the Okanagan composite batholith. 



In the latter part of the Jurassic the granodiorite batholith was uncovered 

 by erosion, then downwarped to receive a vast load of quickly accumulated 

 sediments until more than 30,000 feet of the Pasayten Cretaceous beds were 

 deposited in the area between the Pasayten and Skagit rivers. As yet there is 

 no means of knowing how far this filled geosynclinal extended to the eastward, 

 but it doubtless spread over most of the area now occupied by the Okanagan 

 mountain range. 



The prolonged sedimentation was followed by an orogenic revolution that 

 must have rivalled the mighty changes of the Jurassic. The Cretaceous formation 

 was flexed into strong folds or broken into fault blocks in which the dips now 

 average more than 45° and frequently approach verticality. It was probably then 

 that the Jurassic granodiorites were sheared and crushed into banded gneisses 

 and gneissic granites essentially the same as the rocks now exposed in the 

 Eemmel and Osoyoos batholiths. No sediments known to be of later age than 

 the Lower Cretaceous have been found in this part of the Cascade system; 

 hence it is not easy to date this orogenic movement with certainty. Dawson has 

 already summarized the evidence going to show that many, perhaps all, parts 

 of the Canadian Cordillera were affected by severe orogenic stresses at the close 

 of the Laramie period.* It is probable that the stresses were even greater along 

 the Pacific coast than they were in the eastern zone, where the Eocky Mountain 

 system was built. To this post-Laramie, pre-Eocene epoch the shearing of the 

 granodiorites may be best referred. 



We have seen that there are good reasons for considering the composite 

 Kruger alkaline body as younger than the granodiorites. It is clearly older than 

 the Similkameen granite, as proved by the discovery of fine apophyses of the 

 granite cutting the nephelite rocks. The Kruger body once extended some 

 distance farther west over an area now occupied by the granite. The former, 

 when first intruded, was an irregularly shaped mass without simple relation to 

 its country rocks, the Paleozoic complex. The mode of intrusion was that of 

 either a stock or a chonolith. In the first case the body was subjacent and 

 enlarged downwardly; in the second case it was injected and its downward 



* G. M. Dawson, Bull. Geol. Soc. Am., Vol. 12, 1901, p. 87. 



