THE WORK OF THE OCEAN.
Did you ever think how much work the ocean is doing? If you have ever visited the ocean you know that it is never quiet. The waves are always beating against the shore and sometimes it seems as if they would wash the solid land away.
The ocean is doing different kinds of work. It is like a great animal that men have harnessed. When it is in a pleasant mood it carries the ships safely upon long voyages. When it is angry it often hurls the ships against the hard rocks and breaks them in pieces.
In many places the waves of the ocean are slowly tearing down the land. In other places they are building up the land.
The picture on the next page shows a rough and rocky part of the coast. The waves whiten the ocean with foam as they dash against the cliffs. Here we can easily see that they are doing work. With every storm the waves tear away a little of the land. They are digging holes and caves. We can see them in the picture.
Where the rock is soft the waves work faster and soon make a little bay. The hard rocks wear away slowly and after a time they form points of land sticking out into the water. Sometimes the waves wash around these points of land and make islands of them. Many of the little islands along the coast have been made in this way.
How do the waves work? Have they any tools? Let us see. If we walk along the base of the cliffs at low tide we find the shore strewn with rounded pebbles. As each wave breaks and rolls
back into the ocean we hear the pebbles grinding upon each other.
When the tide comes in and the waves again reach the cliffs they pick up the pebbles and hurl them against the rocky banks. They keep doing this day after day, and do you wonder that at last they make hollows and caves in the solid rock? The larger pieces of rock, which are broken from the cliffs, the waves leave upon the shore until they are smoothly rounded. The little pieces they carry far out, and, at last, where the water is quiet, let them sink to the bottom.
It is in the bay that the waves are making land. Some of the little particles of rock from the cliffs are washed into the bay. Others are brought by the river that enters the bay. The waves make a smooth beach of the little grains of sand. It is a beach on which children delight to play.
The grains of sand are not left in quiet. The waves keep turning them over and over. Some of the sand they pile high enough for it to dry out. Then the wind takes hold of it and builds sand dunes.
The sand which the waves pile up along the shore protects the land. They can no longer get at it and tear it down.