160 



THE WATERS OF THE EARTH 



as points and promontories. In some cases the waves cut 



back so rapidly on lofty coasts that high cliffs are formed. 

 If the material of the coast does not readily break off 



when undercut by the waves, a sea cave may be formed. 



Such is the well-known Fingal's Cave on an island off the 



coast of Scotland 

 where the structure 

 of one of the igneous 

 rock layers allows the 

 waves to quarry it 

 comparatively easily. 

 If a coast stays at 

 the same elevation 

 long enough, or if its 

 material is easily 

 eroded, large areas 

 of what was for- 

 merly dry land may 

 be cut away and 

 brought under the 

 sea. 



In 1399 Henry of 



A LAKE BEACH FORMED BY A STREAM AND 

 WAVE ACTION 



A year after this picture was taken a landslide 

 caused a wave which swept away the entire 

 beach and village. 



Lancaster, afterward 

 Henry IV of Eng- 

 land, returned from 

 his exile and landed 

 at Ravenspur, an important town in Yorkshire, to begin 

 his fight for the crown. A person disembarking at the 

 same place to-day would be so far from shore that 

 he would need to be a sturdy swimmer to reach the 

 beach. The entire area of the ancient town has been 

 cut away by the waves and now lies under the sea. This 



