249 



KUomrtrl. than 200 feet ( 6o m> ) dee P into tne bed-rock 

 itself. This bed-rock is black Cretaceous shale 

 and sandstone. On account of the sombre 

 appearance of the rocks, the gorge is known as 

 the Black Canyon. 



To the east of the southern portal of the tun- 

 nel may be seen typical mud-slide ground. The 

 ground creeps and forms gaping fissures. Where 

 material has broken away to form landslides, 

 steep bluffs remain. These slides and creep of 

 the ground have caused the railroads much 

 trouble and expense. 



About two miles (3-2 km.) below the Black 

 Canyon, the Cretaceous conglomerate (largely 

 granitic) grades down, within a few feet, into 

 an angular breccia, which rests unconformably 

 upon the Nicola rocks. 



54 -6 m. Basque — Opposite Basque siding the Cre- 



87-8 km. taceous ends, and the underlying Paleozoics 

 (Cache Creek formation) appear for the first 

 time. A few miles west of the river may be 

 seen Red hill, named on account of the highly 

 coloured character of the rocks which compose 

 it. The pyritic cherts and sheared rhyolites of 

 the Cache Creek group have been weathered so 

 as to form red outcrops. 



A section of Jura-Trias rocks, intruded by 

 tongues from the underlying granodiorite bath- 

 olith, may be seen a few miles below Basque. 



On nearing Spatsum one may see the west 

 flank of a prominent block mountain composed 

 of Jura-Trias limestones dipping and striking 

 conformably with the slope of the hill. The 

 more resistant, massive Jura-Trias rocks, in- 

 stead of yielding to orogenic stresses by folding 

 and mashing (like the Cretaceous shales and 

 sandstones), yielded rather by bodily over- 

 thrust from the west upon a broad underlying 

 granitic batholith. Clinging to the batholith is 

 a rim of chert due to the contact metamor- 

 phism at the time of batholithic intrusion. 

 60 -8 m. Spatsum— Altitude 854 feet (260-2 m.). On 



97-8 km. the opposite side of the river from Spatsum, 

 35069— io|a 



