What are the four main types of mountains?
What are the four major types of fold mountains?
monoclines. In a monocline, all rock layers dip in the same direction.

chevron. A chevron is a fold in which rock layers look like zig-zags.
slump. A slump fold is the result of slope failure, a type of landslide. ... 
ptygmatic. Ptygmatic folds are a type of slump fold. ... 
disharmonic.