n tbe Stufc of IRatural Scenery 27 



beach, with the perpendicular cliffs for a background, and 

 no longer in danger of destruction. Often these cliffs are 

 covered with ivy and other climbers, and in every fissure 

 stonecrops, saxifrage, and other rock plants find a place 

 sooner or later. When this phenomenon takes place in 

 higher altitudes, the flora is of a different and less robust 

 type. True alpine plants are confined to high mountain 

 regions, but many delicate and truly beautiful rock plants 

 are common in most countries. Sandstone rocks support a 



FIG. 7. ERODED ROCKS, FORMING A SMALL ROCKERY ON THE SHORES OF A RIVER. 



greater and more varied vegetation than any other kind. 

 They are also seen in a great diversity of forms, as they are 

 easily acted upon by heat and moisture, or turned and 

 polished by heavy sandstorms. Limestone is also liable to 

 erosion in a greater or less degree ; the surface becomes more 

 polished, and undermined rocks are seldom ground to gravel, 

 but remain as stones and bowlders in the streams and rivers 

 by which they are undermined. Here also we find numerous 

 rock plants, often of a different type. But nearly all rocks, 

 even ,the solid granite and trap, form cracks and fissures in 



