[camsell] great canon OF FRASER RIVER 53 



uplift. That there has been upHft in the caîïon is evident by the 

 notching of the valley floor by a revival of activity in the stream and 

 that this uplift is post-Glacial is proved by the fact that the notched 

 portion of the valley shows no evidence of glaciation, whereas the bed 

 of the broader upper valley has clearly been smoothed and its whole 

 shape modified by valley glaciation. 



Yale to Agassiz 



At Yale the Fraser river emerges suddenly from the gorge and 

 enters a broader and more open valley which it follows almost to 

 Agassiz where it enters upon the delta. Yale is the head of navigation 

 on the river and no boats do now, or ever have, run beyond that 

 point. In high water even that point cannot be reached by steam- 

 boats which find it impossible to ascend the stream beyond Hope. 

 The grade of the stream between Yale and Agassiz drops from more 

 than 8 feet, which it maintained in the gorge, to 3.7 feet per mile 

 and except for one or two rififles between Yale and Hope the stream 

 flows with a steady, though strong, current. 



From Yale to Hope the trend of the river is due south as above, 

 and it occupies a broadly flaring valley having well wooded sides 

 that slope upwards to heights of 4,000 or 6,000 feet above the river. 



The rocks in which the valley has been incised are granitic, and 

 from an examination of their composition there seems no reason why 

 the gorge characteristics of the valley should not hold as far down as 

 Hope, but when the structure of these rocks is examined critically 

 it is found that they have been greatly sheared along a north and 

 south line and the stream follow^s this zone of shearing. 



In consequence of the ease with which these rocks are attacked 

 by erosion along this shear zone the valley has been excavated to a 

 much greater width than it could be done where the rocks have not 

 been so affected. 



At Hope the stream widens and becomes interrupted by islands 

 of gravel. At this point also it turns abruptly to the west and passing 

 around the southern end of the Coast range maintains a westerly 

 direction to the sea. 



For a few miles below Hope the valley also takes a trend across 

 the strike of the rocks and is thus confined to narrow limits, soon, 

 however, to emerge into a broader expanse on approaching the head 

 of the delta. 



Origin and Development of the Canon 



Since the valley of the Fraser river constitutes the main outlet 

 from the central part of the province of British Columbia to the 



