254 

 Miles and southward course until it reaches Thompson 



Kilometres. . , . c 



Siding. 



The Spence's Bridge Volcanic group is capped 

 a few miles northeast of Drynock by typical 

 basalt of the Kamloops Volcanic group. About 

 ioo feet (30-5 m.) of tuff beds, resembling 

 the Tranquille beds, are present at the contact. 



85-3 m. Thompson Siding — Altitude 670 ft. (204.2 m.). 



137-2 km. At Thompson Siding, the Nicoamen river 

 tumbles over a waterfall to unite with the 

 Thompson which here bends sharply, taking 

 a west course until it reaches the Fraser river 

 at Lytton. The first discovery of gold in 

 British Columbia is said to have been made by 

 an Indian at the mouth of the Nicoamen in 1857. 

 As the train rounds some of the rocky bluffs on 

 the south side of the Thompson Canyon, 

 an occasional glimpse of the snowclad Stein 

 Peak and other Coast Range mountains may 

 be had. The scenery through this canyon 

 portion of the Thompson valley is rugged 

 and mountainous, with huge talus blocks 

 scattered along the channel of the river. There 

 is comparatively little Glacial silt in this portion 

 of the valley. The post-mature upland of the 

 summits grades gradually into the alpine topo- 

 graphy of the Coast range. As the train winds 

 through higher upland country, there is a 

 marked increase in the depth of the tributary 

 valleys beneath its surface. 



Westward of Thompson, the railroad cuts 

 into highly pyritic quartz schists before entering 

 the eastern border of the Coast Range batholith. 



89-7 m. Gladwin — Altitude 745 ft. (227-0 m.). A 



144-3 km. contact zone between the Coast Range batho- 

 lith and Paleozoic schistose rocks, the whole 

 traversed by many Tertiary dykes and chono- 

 lithic intrusions, is exposed on the steep scarped 

 north wall of the canyon between Gladwin and 

 Lytton. A few miles further west, near the 

 mouth of Botanie creek, is an odd granitic 

 ridge named ' The Crag. ' It is cut off sharply 

 to the west by a fault scarp which gives a very 

 irregular outline to the hill. The eastern side 



