26l 



Coast Range batholith, and while the major portion of 

 them is of Jurassic age, some are believed from their 

 structure, to be post-Lower Cretaceous. These rocks, 

 especially the older ones, show shearing and faulting and 

 have two well developed lines of fracture, namely N. I5°W. 

 and N. 20° E., which to a considerable extent influence the 

 direction of the stream. From Yale to Hope they are 

 traversed by a wide shear zone striking north and south, 

 and along this the stream has directed its course. 



Lower Cretaceous rocks occupy the valley of the river 

 below Lytton, and appear as erosion remnants near Hope; 

 they consist of conglomerate, slate and sandstone, which 

 contain a few marine fossils. 



No deposits of Tertiary age occur in the main canyon, 

 though in the delta immediately below there is a great 

 thickness of Eocene beds, and in the region above the 

 canyon are Oligocene sediments, associated with volcanic 

 flows. 



Glacial deposits of till, sand, and gravel fill the lower 

 parts of the valley wherever they have found space for 

 lodgment. They have been carved into terraces by the 

 stream, and more recent deposits of gravel have been 

 formed. These recent gravel deposits are the high-grade 

 gold-bearing placers which caused a great influx of placer 

 miners to the region in 1858 and the years following, and 

 from which many millions of dollars worth of gold have 

 since been won. 



ORIGIN AND HISTORY OF FRASER CANYON. 



The origin and history of Fraser canyon are by no means 

 clear. In attempting to work them out, one need not go 

 farther back in geologic time than the revolution following 

 the deposition of the Lower Cretaceous rocks. It is clear 

 from the geology of the region that during Lower Cretaceous 

 times no stream could have existed along the present 

 course of the river, for the region of the canyon was at that 

 time a geosynclinal basin occupied by an arm of the sea. 

 This region was however elevated into a land area in later 

 Cretaceous times. The development of drainage systems 

 must then have begun in this region, and among them 

 very probably that of the Fraser river, for reasons which 

 follow. 



