The North eastern plateau is an extension of the main Peninsular Plateau (same ages, rocks types and structures).

This should not be confused with the differences in superficial appearances of the Peninsular and North-eastern India, which is a result of climatic phenomenon.

It is believed that due to the force exerted by the north-eastward movement of the Indian plate at the time of the Himalayan origin, a huge fault was created between the Rajmahal Hills and the Meghalaya Plateau.