The Blue Ridge Mountains have the oldest rocks in the state but are no longer in their original forms. They have transformed because they were subjected to intense heat and pressure when the mountains were being pushed up, or upthrusted. The amount of change or rock deformation (how much the rock was squeezed and folded) depends on how close it was to the powerful forces that created the mountains.

The rock deformation is most severe in this easternmost part of West Virginia (near Harpers Ferry, where this photo was taken) because this area was closer to the continental plate collision. As we move westward across the state, the effect of that powerful collision slowly fades. As such, the rocks in the western part of West Virginia show much milder changes and less folding.