__FLATTENED PARALLEL FOLDS__

1B folds are superimposed by further strain (homo or heterogeneous) to give rise to !C or flattened parallel folds. The amount of strain superimposed can be calculated using the equations given in terms of t', T' and F.

__FLATTENING STRAIN RATIO, PHI__

Hudleston showed that the values of t' for higher values of limb dip tend to increase in case of folds that are flattened were initially cuspate.