1.Fold Axis

• The Line of intersection between the axial plane and the surface of any of the consituent rock bed is called axis of fold.

2.Axial Fold

• An Imaginary Plane Which Divides the fold into two equal halves is called axial plane.

3.Plunge of Fold

• The Inclination of the fold axis with the horizontal is called the plunge of fold.

4.Non Confirmity

• The uncinformity in which the older beds formation is made up of plutonic igneous rocks lying below the younger bed of sedimentary rocks, is called as non confirmity

5.Disconfirmity

• The unconformity in which the beds lying below and above the surface of erosion are almost parallel is called disconformity.

6.Chevoron fold

• These are characterized by very long limbs and very narrow hinges (Figure ) and most of the naturally developed chevron folds have an interlimb angle around 60°.