What parts of the earth's surface have floors and walls ? Valleys. A valley is like a long ditch scooped out of the ground. The bottom of the ditch is called the floor. The sides are called valley walls.
Some valleys are places where the ground has sunk. But most valleys are made by rivers and streams. As water flows along,it tears away bits of the land. As years go by, more and more land is worn away. The river sinks deeper and deeper. Steep walls form on both sides of it. Then wind and rain begin to wear away the walls, making the valley wider. In time, the valley becomes a long, V-shaped ditch, with the river or stream flowing along the floor.
Some valleys have grown so wide that they are no longer V-shaped. Some are U-shaped. Others have become deeper rather than wider. Very deep valleys with steep walls are called canyons or gorges.
Some valleys are places where the ground has sunk. But most valleys are made by rivers and streams. As water flows along,it tears away bits of the land. As years go by, more and more land is worn away. The river sinks deeper and deeper. Steep walls form on both sides of it. Then wind and rain begin to wear away the walls, making the valley wider. In time, the valley becomes a long, V-shaped ditch, with the river or stream flowing along the floor.
Some valleys have grown so wide that they are no longer V-shaped. Some are U-shaped. Others have become deeper rather than wider. Very deep valleys with steep walls are called canyons or gorges.
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