RESIDUAL MOUNTAINS are Mountains that evolve when the general level Of the land has been lowered by the agents of denudation leaving the more resistant areas to remain.
A good example of Residual Mountain is Mt. Monadnock in U.S.A., Highlands of Scotland, the Deccan plateau, the ldanre hills etc.
Agents of denudation form Residual Mountains from old fold, block or volcanic mountains. They may also come up from plateaux as hills and valleys that have been dissected by rivers.