SEA-SHORE SCEXEHy. 17 



the coast-wall that can be loosed from their hold, 

 are step by step torn off by their ceaseless attack ; 

 and the firmest rocks are slowly worn and ground 

 away by the sea-sand driven in the water. Num- 

 bers too of plants and of animals living in the sea, 

 such as shell-fish, with the remains of fishes, are 

 thrown up and left upon the beach. 



It is only on flat or gently sloping shores of 

 narrow-mouthed gulfs, running far up into the 

 land, or on coasts where the force of the ocean- 

 swell is broken by sand-banks, or by reefs ofrock at 

 some distance from the land, that this violence of 

 the breakers is assuaged, or altogether calmed. 



If you have ever been at the sea-side, at a place 

 where the tides are strong, and where the shore 

 slants gently to the water, you must have remarked 

 that every wave, as it comes in, runs several paces 

 upwards on the beach, and, immediately retreat- 

 ing, leaves uncovered again much of the surface 

 which it had just overflowed, perhaps, by many 

 feet, until the next wave arriving plays the same 

 part again. If the tide is rising you will observe 

 that the retiring water does not fall quite to its 

 former level, and that almost every fresh wave rolls 

 a little higher up than did the one before it. The 

 advance is scarcely perceived at first, but step by 

 step it becomes more evident. About three hours 

 after the moment of lowest ebb the rise of the 

 tide is strongest ; then again it becomes slower 



c 



