106 LABRADOR 



deep NE.-SW. valley. On the southeast the valley is 

 bounded by a similar arrangement of cliffs and taluses. 

 It ends as a great cul-de-sac, two miles in length, in a thou- 

 sand-foot head-wall over which there cascades a large 

 brook. 



"On landing, I found that the first and natural impres- 

 sion, that this systematic array of scarps and taluses sig- 

 nified a stratified structure for the massif, was justified." 



At the foot of the great cliff the light-colored gneisses 

 and other crystalline schists of the Basement form broad 

 ledges well scoured by the ice of the Glacial Period. Their 

 gently rolling surface is considerably more uneven than the 

 old " fossil" land-surface on these same crumpled, gnarled, 

 and twisted rocks. The overlying, veneering strata of the 

 plateaus include black slates, quartzites, and sandstones, 

 apparently all sea-bottom deposits ; but probably more than 

 1500 feet of the half-mile of thickness in these bedded rocks 

 belongs to a volcanic formation. For unknown centuries 

 this part of the Labrador must have been the home of one 

 or more, perhaps many, volcanoes of large size. Millions 

 of years ago they erupted enormous volumes of "ash" and 

 other debris of lava. Most of the lava was shattered into 

 angular fragments, coarse and fine, by the violence of ex- 

 plosion. In the resulting deposits one can find abundant 

 and very perfect " bombs" with the rounded shapes and 

 cracked surfaces of lava masses freezing as they spun through 

 the air from the mouth of Nature's cannon. Other thick 

 sheets of solid lava represent the quiet flows that signify 

 yet greater power in the eruptive force. 



So far only the most cursory examination has been given 

 this important rock-section. No organic fossils have been 



