260 THE BEAUTIES OF NATURE chap. 



approach so near that there is not even room 

 for the river and the road : in that case 

 Nature claims the supremacy, and the road 

 has to be carried in a cutting, or perhaps in 

 a tunnel through the rock. In other cases 

 Nature is not at one with herself. In many- 



Fig. 25. — Section of a river valley. The dotted line ehowe a slope or 

 talue of debris. 



places the debris from the rocks above would 

 reach right across the valley and dam up the 

 stream. Then arises a struggle between 

 rock and river, but the river is always vic- 

 torious in the end ; even if dammed back for 

 a while, it concentrates its forces, rises up 

 the rampart of rock, rushes over trium- 

 phantly, resumes its original course, and 

 gradually carries the enemy away. 



