The earth’s crust
The earth we live on is made up of land, water and air. The air forms a mantle round the earth, extending upwards to about 18 km. the portion of the earth that is not covered by water is our land. The height of the land us measured by the number of meters it stands above sea level.
Plain a plain is an area of lowland. It is either level undulating. It seldom rises more than a few meters above sea level –like the great fertile plain of North India.
A plateau is an elevated upland with an extensive level surface bounded on one side at least, by a downward slope –like the Deccan plateau in India.
Hills
The height of a piece of land refers to the number of meters it stands above sea level.
A hill is a raised piece of land. Some hills are low and some are high. Some hills are flat on top while others have a steep edge. A hill with a steep edge is called a cliff. Some hills have gentle slopes but steep summits. Some hills are covered with layers of soil with trees and grass growing on them. There are again hill made of bare rocks. Hills like the Western and Eastern Ghats in India are called Ghats because of the step-like form.
Mountains
Avery high is a mountain. A continuous line of mountains is called arrange. Some mountains, like the Himalayas, are so high that they are covered by snow which does not melt even in summer.
Valleys
A valley is the low- lying land found between two hills or mountain. Some valleys are broad and flat while others are steep and narrow. Valleys are generally fertile land especially when a river flows through the valley, as for instance the Brahmaputra valley in India.
How to identify geographical features in maps
When you open your atlas you notice that geographical feature is generally denoted by certain standard colors on the map. Seas and other water bodies are always colored blue. Different shades of blue are used and darkness shades indicate that the sea is deeper there.
Plains are always colored green. The darker shades of green indicate that the plain is lower there. Sometimes valleys are also green.
Plateaus are always colored yellow. Hills are always colored brown. The darker shades of brown show that there hill is higher. Mountains are colored brown and the snowlines are shown in white.