VALLEYS. 183 
The Creux du Vent, and the Cirque de St. 
Sulpice are two of the finest examples. 
Terraces. 
As regards the sides of valleys, other things being 
equal, the harder the rocks the steeper will the slope 
of the sides be. Very hard rocks indeed are often 
almost, or for some distances quite, perpendicular. 
The slope may be uniform in cases where the strata 
are similar and of great thickness, as for instance in 
the valley of the Reuss above Amsteg where the 
Bristenstock forms a grand pyramid of Crystalline 
rock, or where the slope coincides with the dip of 
the strata, as in the valley of Lauterbrunnen, where 
the right side of the valley presents immense sheets 
of Jurassic rock. 
In most cases, however, some of the strata along 
the side of the valley are harder than others, and 
the consequence is that we have a succession of 
terraces; gentler slopes indicating the softer, and 
steeper ones the harder beds. 
Figs. 44 and 45 show some terraces in the valley 
of the Bienne (Jura) due to the presence of hard 
calcareous layers. 
These “weather” terraces (Figs. 54, 55 pp. 202, 
203) must not be confused with the “river terraces” 
