Revision Notes for Chapter 2 Physical Features of India Class 9 Geography

• India is a vast country with varied landforms which has all major physical features of the earth i.e. mountains, plains, deserts, plateaus and islands.

• The Himalayan Mountains
• The Northern Plains
• The Peninsular Plateau
• The Indian Desert
• The Coastal Plains
• The Islands

• It is geologically young and structurally folded mountains which run along the northern borders of India.
• → The ranges run from west (from Indus) to east direction (to the Brahmaputra) covering a distance of about 2,400 Km representing loftiest peaks in the world.
• Width varies from 400 Km in Kashmir to 150 Km in Arunachal Pradesh. Altitude (Height) variations is greater in the eastern half than those in the western half.

• Longitudinal divisions of Himalayas:
→ The Great or inner Himalayas or the 'Himadri'
→ The lesser Himalaya or 'Himachal'
→ The Shiwaliks

• The Great or inner Himalayas or the 'Himadri':
→ It is the northernmost range and most continuous range consisting of the loftiest peaks with an average height of 6,000 metres.
→ It contains all the famous peaks. The folds are asymmetrical in nature.
→ The basic part of this Himalayas is composed of granite.
→ It is perennially snow bound, and a number of glaciers descend from this range.

• The lesser Himalaya or 'Himachal':
→ It lies south of the Himadri forms the most rugged mountain system.
→ It is mainly composed of highly compressed and altered rocks.
→ The height varies between 3,700 and 4,500 metres and the average width is of 50 Km.
→ Longest and most important ranges are PirPanjal range and Dhaula Dhar and the Mahabharat ranges.
→ Famous valley of this range are the Kashmir, the Kangra and Kullu Valley in Himachal Pradesh. → Also, this range is famous for hill stations.

• The Shiwaliks:
→ This is the outermost range of the Himalayas.
→ They extend over a width of 10-50 Km and have a height varying between 900 and 1100 metres.
→ It is composed of unconsolidated sediments brought down by rivers from the main Himalayan ranges.
→ These valleys are covered with thick gravel and alluvium.

• The longitudinal valley lying between lesser Himalaya and the Shiwaliks are known as Duns.
→ Dehra Dun, Kotli Dun and Patli Dun are some of the well-known Duns.

• Himalayas divisions on the basis of regions from east to west (divisions have been made by the river valleys):
→ Punjab Himalayas: The part of Himalayas lying between Indus and Satluj. From west to east respectively, regionally known as Kashmir and Himachal Himalaya.
→ Kumaon Himalayas: The part of the Himalayas lying between Satluj and Kali rivers.
→ Nepal Himalayas: The part lying between Kali and Tista rivers.
→ Assam Himalayas: The part lying between Tista and Dihang rivers.

• The Purvachal or Eastern hills and mountains:
→ The mountain ranges of Eastern India. It is marked by the Brahmaputra.
→ The Himalayas bend sharply to the south and spread along the eastern boundary of India after the Dihang gorge.
→ These hills running through the north-eastern states i.e., Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, and eastern Assam states and are mostly composed of strong sandstones which are sedimentary rocks.
→ Hills are covered with dense forests. It comprises the Patkai hills, the Naga hills, Manipur hills and the Mizo hills.

• The Peninsular plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks.
• It was formed due to the breaking and drifting of the Gondwana land.

• The plateau consists of two broad divisions:
→ The Central Highlands
→ The Deccan Plateau

• The Central Highlands: It lies to the north of the Narmada river covering a major area of the Malwa plateau.
→ The Vindhyan range is bounded by the Central Highlands on the south and the Aravalis on the northwest.
→ The further westward extension gradually merges with the sandy and rocky desert of Rajasthan.
→ Rivers in this area: the Chambal, the Sind, the Betwa and Ken.
→ The Central Highlands are wider in the west but narrower in the east.
→ The eastward extensions of this plateau are locally known as the Bundelkhand and Baghelkhand. → The Chotanagpur plateau marks the further eastward extension, drained by the Damodar river.

• The Deccan Plateau: It is a triangular landmass that lies to the south of the river Narmada.
→ The Satpura range bound its broad base in the north while the Mahadev, the Kaimur hills and the Maikal range form its eastern extensions.

→ It is higher in the west and slopes gently eastwards.

• An extension of Deccan Plateau is also visible in the northeast– locally known as the Meghalaya, Karbi-Anglong Plateau and North Cachar Hills.
→ It is separated by a fault from the Chotanagpur Plateau.
→ Three Prominent hill ranges from the west to east are the Garo, the Khasi and the Jaintia Hills.

• A distinct feature of the peninsular plateau is the black soil area known as Deccan Trap.
• The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan Plateau respectively.

• The Indian desert lies towards the western margins of the Aravali Hills.
• It is a land of undulating topography covered with sand dunes.
→ This region receives very low rainfall below 150 mm per year.
→ It has arid climate with low vegetation cover.
• Luni is the only large river in this region.
• Barchans (crescent shaped dunes) cover larger areas but longitudinal dunes become more prominent near the Indo-Pakistan boundary.

• The narrow coastal strips flank the Peninsular Plateau, running along the Arabian Sea on the west and the Bay of Bengal on the east.

• It consists of three sections:
→ Northern part of the coast is called the Konkan (Mumbai – Goa)
→ Central stretch is called the Kannad Plain
→ Southern stretch is called the Malabar coast.

• The plains along the Bay of Bengal (east part) are wide and level.
→ The northern part is known as the Northern Circar, while the southern part is known as the Coromandel Coast.

→ Large rivers such as the Mahanadi, the Godavari, the Krishna and the Kaveri have formed extensive delta on eastern coast.
→ Lake Chilika is an important feature along the eastern coast.

• The Lakshadweep Islands group in the Arabian Sea is close to Kerala.
→  This group of islands is composed of small coral islands.
→ The Lakshadweep Islands were earlier known as Laccadive, Minicoy and Amindive.
→ It covers small area of 32 sq km.

→ Kavaratti island is the administrative headquarters of Lakshadweep.

→ The Pitti island, which is uninhabited, has a bird sanctuary.

• The Andaman and Nicobar Islands are an elongated chain of islands located in the Bay of Bengal.
→ They are bigger in size and are more numerous and scattered.
→ The entire group of islands is divided into two broad categories – The Andaman in the north and the Nicobar in the south.
→ These islands are an elevated portion of submarine mountains.

• The mountains are the major sources of water and forest wealth.
• The northern plains are the granaries of the country.
• The plateau is a storehouse of minerals, which has played a crucial role in the industrialisation of the country.
• The coastal region and island groups provide sites for fishing and port activities.