 Stratigraphic profiles of these rock layers can be seen at the southern edge of the West Elk Mountains where the Gunnison River has eroded through the volcanic strata.A good example can be seen at the Dillion Pinnacles in Curecanti National Recreation Area.The resistant welded tuff that caps Dillon Mesa is on top, overlying the West Elk Breccia, which has eroded into the pinnacles.