The concept of orogeny has undergone change through time and has been the subject of many interpretations, even during the same era. At present, it is vague and varied in definition and in implication. The orogeny concept is comprised of at least 12 criteria, which are used either singly or in various combinations. Further, the concept is viewed as a process and as an event. Concepts of orogeny are fundamentally either morphologic or deformational. A utilitarian concept can be based solely on the criteria of deformation, geographic extent, scale, and time.