 Mountain building is normally focused between inland from a subduction zone boundary.Geologists continue to gather evidence to explain the rise of the Rockies so much farther inland; the answer most likely lies with the unusual subduction of the Farallon plate, or possibly due to the subduction of an oceanic plateau.At a typical subduction zone, an oceanic plate typically sinks at a fairly steep angle, and a volcanic arc grows above the subducting plate.