154 LABRADOR 



Bowdoin Canyon was so named by Gary and Cole, who 

 discovered it in 1891. Issuing from the basin at the foot 

 of the great cascade, the river zigzags in half-mile courses 

 to the east and southwest until it finally issues into the main 

 valley. The distance from the falls to the mouth of the 

 canyon is eight miles in a straight line, but by the river 

 it is more than twice that distance. The canyon is cut 

 sharply and nearly perpendicularly out of the granites 

 and other crystalline rocks to a depth of over five hundred 

 feet below the general surface of the plateau. The zigzag 

 courses of the gorge conform with the directions of two sets 

 of jointage planes, which split the granites into huge blocks 

 in the area below the falls. The cracks appear to influence 

 the direction of the river courses, and to have greatly as- 

 sisted the water in clearing out the gorge. The canyon 

 is probably a new valley excavated by the river since the 

 Glacial Period. The ancient river which, in pre-Glacial 

 time, flowed down the main valley seems to have been 

 diverted by dams of glacial drift and perhaps by local 

 changes of level, so that it now flows on the surface of the 

 plateau to the north of the old valley. On reentering the 

 old valley with such a tremendous fall, the river has cut 

 out the canyon in a comparatively short period of time. 

 The break in the surface of the plateau is so sharp that an 

 approach to within a few yards of the edge may be made 

 without any indication of its presence, the first warning 

 being the hoarse roar of the rapids far below. Across its 

 top the gorge rarely exceeds a hundred yards ; at the bottom 

 the river is confined to a width of a hundred feet. The 

 difference in level between the water in the basin and that 

 issuing into the main valley is two hundred and sixty feet, 



