Pico Huamlla, Cordillera Yauyos. With the American Bill Douglas, I visited the Cordillera Yauyos, taking the Huancayo-Cañete road. At Santo Tomas we drove through a narrow limestone canyon with 1000-foot vertical or overhanging walls, often festooned with stalactites. The town receives only three to four hours of sunlight a day. The canyon ends at Alis. We left the car near Tinko and hiked up the Río Cañete, initially beside terraces of limestone alluvium permeated and overlain with calcium carbonate, forming a rare outdoor display of dripstone cave formations. We turned west up the Río Miraflores, passing through another canyon with overhanging walls beyond which the stream disappears underground for a kilometer. Above the village of Miraflores we entered Quebrada Toma, and I made a solo ascent of Huamalla (c. 5200 meters or 17,061 feet; IGM Hoja Yauyos, 1:100,000) on June 17 by its southeast rock ridge.