3o6 



George E. Nichols, 



bird cherry (Primus pennsylvanica), etc. In the course of time 

 a closed coniferous forest may be developed, and, under favorable 

 conditions, this may be superseded eventually by a forest of the 

 regional climax type. 



One of the commonest types of talus in northern Cape Breton 

 is shown in Fig. i6. The rock fragments are relatively small 

 and the rock mass is much less stable than the large-bouldered 

 talus, though more so than the gravel slide. The common 





-T?^-tap'-i4^!»il2!i^ 



Figure i6. — Pioneer association of white spruce, etc., on granitic talus ; 

 Barrasois. 



pioneers here are the white spruce, the raspberry, Dicksonia, and 

 Anaphalis. 



2. The Formation-types of Uplands along Streams 



a. INTRODUCTORY 



In a general way, two topographic features are intimately 

 associated with streams : valleys and flood plains. In northern 

 Cape Breton the valleys range from deep, narrow ravines and 

 ^gorges in which the stream occupies entirely the narrow floor, on 



