Quimsa Cruz. I spent almost six weeks in several forays into the Cordillera de Quimsa Cruz, but the results were poor because of the wintry weather that hit the north-central Andes during June and July. In one campaign, I hiked from the mines of La Argentina and Carmen Rosa to Lake Chatamarca on the Amazon side. Walking north along the west bank of the lake, I went up the second, unnamed valley and camped at 16,000 feet near the Chamacani Glacier under strong winds. On June 26, I made the first ascent of Cerro Chamacani (“Dark One; c. 5200 meters, 17,061 feet) by its north side. From the lake it is seen as a square rock block, crowned by a long ridge of towers and needles. I climbed the spike I estimated to be the highest. I also made several other explorations and attempts. In the San Pablo valley, west of Mina Carmen Rosa, I ascended to a 5100-meter peak on the divide. I climbed a side valley of the Pacacha River to 5100 meters, the twin Bajaderías valleys to the base of the glaciers and the twin Pacuni valleys to attempt Jacha Pacuni (5560 meters, 18,242 feet), which I abandoned at 5200 meters in an exposed gully. On July 6, I reached the Mina Monte Blanco, walked around lovely Lake Huallatani and camped on its northern shore. The next day, I climbed the rather easy Cerro Mamani (5570 meters according to climbers, but only c. 5400 meters or 17,717 feet by my observations.) On the summit was the cairn left by Germans Wilfried Kühm and Josef Prem on September 11, 1939. I could not remove the bottom rocks frozen to the ground to see the records of my predecessors.