are numbered according to their order of formation with the letter D denoting a deformation event. For example, D₁, D₂, D₃. Folds and foliations, because they are formed by deformation events, should correlate with these events. For example, an F₂ fold, with an S₂ axial plane foliation would be the result of a D₂ deformation.

Metamorphic events may span multiple deformations. Sometimes it is useful to identify them similarly to the structural features for which they are