Symmetrical fold-is when both limbs are equal in steepness on both sides because the compression sides are equal and opposite.
Asymmetrical fold-occurs when one side is steeper than the other because the forces on one side are more than the other force.
Over-fold–occurs when one fold is pushed over the adjoining limb due to increasing compressional forces.
Recumbent fold-occurs when the limbs are nearly parallel to each other and the axis of the fold is horizontal.
Over-thrust fold- occurs when the a recumbent fold is acted upon by extremely powerful compressional forces which causes one of the limbs to fracture. The upper part of the recumbent fold is thrust forward along the fracture plane.