what are valleys like
A valley is a hollow or surface depression of the earth bounded by hills or mountains, a natural trough in the earth's surface, that slopes down to a stream, lake or the ocean, formed by water and/or ice erosion.Systems of valleys extend through plains, hills, and mountains. valley's sides are called valley walls or valley slopes. A valley wall is the side slope of a stream or glacial valley. Rain, frost, wind and the atmosphere are loosening materials which fall into the stream and are carried away.