Cerro Morro Overo, Central Andes. A number of medium-sized but bold rock peaks near the Mendoza frontier with Chile remain unclimbed, in part because of poor rock. In late December, I entered several relatively unexplored valleys north and south of the international highway to Santiago. On December 26, above the Quebrada Mistay on its northern rim, I climbed P c. 4400 (14,436 feet; “Cerro Peñas Amarillas”). Four days later, I ascended P 4180 (13,714 feet), south of beautiful Lake Potrero Escondido. I named this “Cerro Peñas- coso.” Above Quebrada Navarro, south of the highway, on January 10, 1989, I climbed the striking rock pyramid adorned with black-and-yellow bands of P 4437 (14,558 feet), which was christened “Morro Overo.” The route was up the north face and north gully and was extremely unstable.