GROUND, ROCK, PFATER 135 



nects them by a smooth concavity with the floor of the valley or with 

 the opposite side. 



Some valleys are formed by steep slopes, perhaps leaving the up- 

 land at a sharp angle, though they may be continuations of a moun- 

 tain slope above, and meeting below at a sharp angle, where lies the 

 stream which is still obviously at work in deepening its channel and 

 causing more material from the side slopes to fall into its bed. In 

 such valleys the attention of the observer is brought sharply to the 

 convergence of the slopes at the bottom. (See Plate 23.) These 

 valleys are almost certainly more striking in their effect than are the 

 gently-sloped valleys, and in those cases where the eroded material is 

 hard they may become steep-sided gorges of almost any degree of se- 

 clusion and romantic wildness and gloom. 



Other valleys have nearly vertical sides terminating sharply against 

 a flat floor below, which thus is made to form almost a world in itself. 

 Such a valley gives to the full a sense of seclusion, but may have, unlike 

 the narrow gorge, an eff^ect of sufficient openness and light and peace. 

 Such valleys are also commonly the result of stream-erosion in a ma- 

 terial such that their sides may stand very steep, and usually the flat 

 floor of the bottom is made by deposition of material by the valley 

 stream. 



In arranging paths in a valley, to display its character to the best Choice of 

 advantage, the depth of the valley should be made to tell at its full p^^potntfor 

 value. A U-shaped valley, or one with a flat floor and very steep sides. Effect of 

 may be well seen from the bottom if this is not choked with trees, for f^alley 

 the view includes at once the whole depth from the floor to the upper 

 rim. A V-shaped valley, however, particularly when the immediate 

 banks of the stream are steeper than the average side slope of the 

 valley, as is frequently the case, is often not seen to good advantage 

 from the bottom, as the intermediate parts of the slope prevent a full 

 view of the inclosing sides. In such cases, and often in other valleys, 

 the best view is obtained by looking along the valley from some pro- 

 jecting buttress, considerably above the bottom, commanding the whole 

 sweep of the sides and getting an additional effect of depth by a de- 

 scent, perhaps steep, from the viewpoint to the bottom of the valley. 

 If considerable exertion is necessary in climbing up or down to the 



