The geological nomenclature of faults is chiefly concerned with a geometrical treatment of local problems of underground structures, and gives little or no consideration to surface forms. The physiographic nomenclature of faults is concerned almost wholly with large topographical problems of surface forms as determined by the action of erosional processes on faulted structures. The terminology here suggested for surface forms of this class is closely related to a systematic method of physiographic description which may be called the method of “structure, process, and stage,” in that it recognizes, first, the underground structure—often called the geological structure—of the mass which exhibits physiographic forms in its upper surface; second, the process or processes which have worked on the structural mass so as to modify its initial surface forms; and, third, the stage reached by the action of process on structure in producing the actual forms . . .