THE STORY THE SEA TOLD 155 



tance and then pile into bars or shoals which 

 are exposed at low tide. Gradually more 

 sand may wash into the spaces between these 

 bars and in time the sandy beach may stretch 

 unbroken for a far greater distance than be- 

 fore the sea cut away the shores. Such alter- 

 nate cutting and filling may continue for years 

 on a sandy coast, or the wind, whipping the 

 loose sand into hills, may form dunes which 

 become bound together with growing plants 

 and the once-flat beach may be transformed 

 into a coast of bluffs and hills with only a 

 narrow strip of wave-washed beach along 

 their bases. 



If the shore is rocky and bold the storms 

 may undermine the cliffs and cause great 

 masses to fall to the sea where, in time, they 

 will be worn and ground into pebbles and 

 shingle which will form a barrier to protect 

 the cliffs above from further damage. If the 

 shores are muddy, deep channels may be cut 

 into the yielding material by heavy waves and 

 the water, filling these, may leave the mud-flat 

 exposed to dry and harden and in time be- 

 come solid land. 



