Monadnock

An inselberg is an isolated hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain. The word is of German origin and means "island mountain"; the name was originally coined to describe the abundant such features found in southern Africa. The Native American name monadnock is also sometimes used as an alternative term, particularly in the United States.

Inselbergs are typically, though not only, formed in tropical areas. Volcanic or other processes may give rise to a body of rock resistant to erosion, inside a body of softer rock such as sandstone which is more susceptible to erosion. When the less resistant rock is eroded away to form a plain, the more resistant rock is left behind as an isolated mountain.

Notable inselbergs include:

• Sugarloaf Mountain in Rio de Janeiro, Brazil
• Uluru and Kata Tjuta in Australia
• Mount Monadnock, New Hampshire, USA
• Stone Mountain, Georgia, USA
• Mount Ascutney, Vermont, USA
• Mount Katahdin, Maine, USA
• Panola Mountain, Georgia, USA
• Pilot Mountain, North Carolina, USA
• Rib Mountain, Wisconsin, USA
• Enchanted Rock, Texas, USA
• Mulanje Massif in Malawi.