Quote Originally Posted by jbgibson View Post
I.e. not all continents = central lump of mountains surrounded by wide swaths of plains (sombrero form)
This is actually pretty much non-existant. Mountains occur along seams. These may be seams that have since fused solid (the Urals), seams between continents colliding (The Himalayas). seams where ocean plate is subducting under a continent (The American Cordillera) or other ocean plate (Japan), or the remains of an old mountain range from an earlier collision which has now opened back up (The Appalachians). Then there are complex situations that combine elements, like the Alps and Atlas mountains around the Mediterranean or the Southern Alps in New Zealand, and odd things like Hot Spots (Hawaii, Iceland) which produce isolated volcanoes.

A "lump" or "spine" in the middle of a continent though is just wrong. It's a result of thinking of them as just being big islands as islands do often have a central lump or spine.