306 



Gcoi'i^^c I'.. iXicliols. 



bird chcM-ry {Pruiiiis pi'iuisylz'anica), 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 conditions, this may be superseded eventually by a forest of the 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. 16. The rock fragments are relatively small 

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

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



l-'iGUKE lO. — Pioneer association oi wiiilo spruce, etc., on i;ranitic talus; 

 Barrasois. 



pioneers here are the white spruce, the tas])berry. Picksoiiia, and 

 Anaplwlis. 



2. The Formation-types of Uplands along Streams 



O. INTRODUCTORY 



In a general way, two topographic features arc intimately 

 associated with streams : valleys and flood plains. In northern 

 Cape Breton the valleys range from deep, narrow ravines and 

 j[^orges in which the stream occupies entirely the narrow floor, on 



