25 



of channels, swings from bank to bank washing alter- 

 nately the slopes on either side. 



The valley bottoms are fiat and built of alluvium, 

 and there is a marked absence all across the range of 

 boulder clay and other deposits of the Glacial age. These 

 have either been destroyed or buried beneath recent 

 river accumulations. 



Mile 68 to 74. — A wide band of crystalline schists, 

 the widest in the range, occurs at this point. The dark 

 micaceous schists occur in bands, occasionally broken 

 and brecciated, and in lenses alternating with striped 

 and banded gneisses. Aplite and pegmatitic dykes, 

 cutting all the varieties, occur in places, but are not so 

 numerous as in the western part of the range. The 

 schistosity here is often flat or in easy folds. 



Mile 83. — The eastern border of the main Coast 

 Range batholith is crossed at this point. Its junction 

 with the bordering rocks of the Kitsalas formation is 

 concealed along the railway. 



Mile 83 to 91. — Almost continuous exposures of the 

 rocks of the Kitsalas formation are displayed in the 

 numerous cuts along this stretch. The rocks are largely 

 of volcanic origin and include porphyrites, andesites, and 

 altered tuffs and breccias. They show considerable 

 fracturing, but are only rarely crushed into schists. A 

 feature of the formation is the extensive development of 

 epidote in rounded and irregular kernels and along fracture 

 planes. Granitic dykes are numerous. 



Mile 91. — The Coast Range mountains gradually 

 decrease in height from Mile 86 eastward, and at Mile 91 a 

 wide valley occupied north of the Skeena by the Kitsum- 

 gallum river is reached. This great depression, four miles 

 in width where crossed by the Skeena, traverses the country 

 in a north and south direction, completely piercing the 

 Coast range, and is evidently of great age, long antedating 

 the initiation of the present drainage system. Its origin 

 and history have not been worked out. North of the 

 Skeena, the valley is floored with heavy deposits of sand, 

 loose gravels and clays, post-Glacial in age and partly 

 marine in origin. 



A change in the character of the Skeena River valley 

 is noticed after passing the mouth of the Kitsumgallum. 

 Below this point steady deposition has been going on since 

 the retreat of the sea, and the valley bottom is a maze of 



