After examining the young and folded mountains of the north and much younger plains to their south, one can move down further south. It is the oldest structure of the Indian subcontinent. As a matter of fact, the slow but stable progress of this landmass towards north and north-east is accountable for the construction of the Himalayas and the Northern Plains instead of the Tethys of geological times. The peninsular plateau is further split up into the Central Highlands and the Deccan Plateau.

The Central Highlands- The northern part of the peninsular block is called the Central Highlands, though they are not truly towering. It is created from solid igneous and metamorphic rocks. The block comprises two parts, delimited by the west-flowing Narmada. Vindhyas and its eastern elongations border the one lying to the north on one side. Towards the north-west it is lined by the Aravallis. The plateau stretches further west, but is cut across by the sandy and rocky desert of Rajasthan. These are pretty old fold mountains. On the third side, this plateau unites progressively in the Gangetic Plains of the north. This is known as the Malwa Plateau. It is reasonably wide in the west and becomes tapered in the east. The eastern part is known as Bundelkhand and Baghelkhand in southern Uttar Pradesh. In South Bihar it is called Chotanagpur plateau. The southern tributaries of the Yamuna and Ganga irrigate the plateau.

The Deccan plateau- The Deccan Plateau stretches from the Vindhyas to the southern tip of the peninsula. This triangular plateau is at its broadest in the north. The Vindhyan Range and its eastern elongations viz. Mahadev Hills, Kaimur Hills and Maikal Range form its northern edge. Towards the west, the plateau has still pretty exorbitant edge, formed by the Western Ghats. This mountain range runs from north to south, nearly parallel to the Arabian Sea. The Western Ghats are recognised by various local names. In Maharashtra and Karnataka they are called Sahyadri. Down south, they are called the Nilgiris in Tamil Nadu. Still further south, along the Kerala and Tamil Nadu border, they are known as Anaimalai and Cardamom Hills. The Deccan Plateau is the highest along its western periphery and lightly inclines towards the Bay of Bengal in the east. The Western Ghats are comparatively elevated in their southern part. Anai Mudi, the highest peak, is 2,695 metres above sea level. Udagamandalam is a renowned hill station of the south, located in Tamil Nadu.

Contrasting the western border, the eastern limit of the Deccan plateau is less steep. It is in fact extensively broken into small hills by the rivers like Mahanadi, Godavari, Krishna and Kaveri. The Eastern Ghats are locally identified by several names.

The north-western part of the Deccan Plateau deserves special mention. It is constructed of igneous rocks of volcanic origin. From the earths extremely roiling interior, lava exudates through enormous clefts or crevices in the earth`s crust. It took millions of years and it is judged that the volume of lava flow had outperformed the volume of the Himalayas. Geologists consider that this activity was intimately related to the birth of the Himalayas.

While all the key rivers of the peninsular block flow into the Bay of Bengal, the Narmada and Tapi are the only two rivers streaming in the opposite direction, to fall into the Arabian Sea. These long rivers flow by very tapered lengthened valleys. The Vindhyas in the north and the Satpuras in the south gird the Narmada valley. To the south of the Satpura lies the Tapi River. These two rivers alleys are believed to be prehistoric rift valleys. The two rivers unite into the sea through constricted estuaries.