valleys found between the Siwaliks and the Lesser Himalayas are called Duns in the west and Duars in the east. These are the ideal sites for the development of settlements in this region. . Purvanchal Hills These are the eastern off-shoot of Himalayas.
It extended in the north-eastern states of India. Most of these hills are located along the border of India and Myanmar while others are inside India. Dafla Hills, Abor Hills, Mishmi Hills, Patkai Bum Hills, Naga Hills, Manipur Hills, Mizo Hills, Tripura Hills, Mikir Hills, Garo Hills, Khasi Hills and Jaintia Hills are the hills which are collectively known as Purvanchal Hills . Importance of the Himalayas • The Himalayas block southwest monsoon winds and causes heavy rainfall to north India.
• It forms a natural barrier to the sub- continent. • It is the source for many perennial rivers like Indus, Ganges, Brahmaputra etc. • The Northern Mountains are described as the paradise of tourists due to its natural beauty. • Many hill stations and pilgrim centres like Amarnath, Kedarnath, Badrinath, Vaishno Devi temple, Buddhist, Jain and Sikh centres are situated here.
• It provides raw material for many forest based industries. • It prevents the cold winds blowing from the central Asia and protects India from severe cold. • The Himalayas are renowned for the rich biodiversity. India – Location, Relief and Drainage soil is dark in colour, rich in humus content, well drained and useful for agriculture.
d) The Khadar Plains The new alluvium tracts along the courses of the rivers are known as the ‘Khadar’ or ‘Bet’ lands. The Khadar tracts are enriched by fresh deposits of silt every year during rainy seasons. The Khadar land consists of sand, silt, clay and mud. It is highly fertile soil.
e) Delta Triangle-shaped fertile land at the mouth of The Ganga and Brahmaputhra rivers is called as the Sundarban delta. It is the biggest and fastest-growing delta. It is an area of deposition as the river flows in this tract sluggishly. The deltaic plain