GEOLOGICAL RELATIONS 359 



down-warped marine area just west of the Pasayten river. To furnish 

 such a volume of sediment, there would appear to have been in the region, 

 preferably to the eastward of the Pasayten, a much larger area of granitic 

 rocks than is now represented in the Eemmel and Osoyoos batholiths com- 

 bined. It is possible, indeed, that at that time these two batholiths were 

 part of one huge mass of granodiorite which largely occupied the site of 

 what is now the Okanagan Composite batholith. Both Eemmel and 

 Oso}roos granodiorites have suffered profound metamorphism, so similar 

 in its effects in the two rock masses that it may most simply be attributed 

 to the same period of orogenic disturbance. The systematic parallelism 

 of the shear zones in each batholith and the fair accordance in trends of 

 the zones occurring in both batholiths suggest that there has been but one 

 such revolutionary disturbance since the batholiths were irrupted. If 

 this be true, the period is identical with the post-Lower Cretaceous epoch, 

 when the Pasayten Lower Cretaceous was thoroughly folded and crushed 

 into its present greatly deformed conditions in the Hozomeen range. 



The Osoj^oos and Eemmel batholiths are thus probably contempo- 

 raneous probably both post-Carboniferous and certainly pre-Cretaceous. 

 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, 60 miles is the 

 minimum width of the Okanagan Composite batholith. 



In the latter part of the Jurassic the granodiorite batholith was un- 

 covered by erosion, then down warped to receive a vast load of quickly 

 accumulated sediments until more than 30,000 feet of the Pasayten Cre- 

 taceous beds were deposited in the area between the Pasayten and Skagit 

 rivers. As yet there is no means of knowing how far this filled geosyn- 

 clinal 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 rivaled the mighty changes of the Jurassic. The Cre- 

 taceous formation was flexed into strong folds or broken into fault blocks 

 in which the dips now average more than 45 degrees and frequently ap- 

 proach verticality. It was probably then that the Jurassic granodiorites 

 were sheared and crushed into banded gneisses and gneissic granites essen- 

 tially the same as the rocks now exposed in the Eemmel and Osoyoos bath- 

 oliths. No sediments known to be of later age than the Lower Cre- 

 taceous 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, 



