The Ortler Alps as well as the Sobretta-Gavia Group are also sometimes classified with the Central Alps, because they lie north of the geological fault of the Periadriatic Seam; in a general regional geographic sense, however, they are seen as part of the Southern Limestone Alps, because they are found south of the longitudinal trough Veltlin (Adda)-Vintschgau (Etsch). Also in terms of rock, the Ortler main crest is part of the Southern Limestone Alps.