The development of synclinal ridges and anticlinal valleys in a folder region is named as

A ridge and valley landscape is characterized by alternating narrow ridges and parallel valleys that develop in folded mountain regions where differential erosion occurs. The more resistant rock layers form ridges (synclinal ridges when the resistant layer is in a syncline) while less resistant layers are eroded to form valleys (anticlinal valleys when the resistant cap is eroded from an anticline). This creates the distinctive pattern where valleys sit over anticlines and ridges over synclines - an inversion of the original structural relief.