Cerro Arenales, Patagonia. An expedition, jointly sponsored by the Japanese Alpine Club and the Chilean Federación de Andinismo, made the first ascent of the Cerro Arenales (11,310 feet), which lies in the Cochrane Range above the northern part of the Continental Icecap (Hielo Continental). Under the joint leadership of the Chilean Germán Mills and the Japanese Tanaka, the group set out in late January from the Río Baker. Difficult river crossings, rough terrain, and bad weather complicated the approach march to base camp on the Lago Colonia. Finally on March 6, 1958 the Japanese Takagi and Emanji and the Chilean Kurt Klaussen reached the summit. Two days later the Chileans Germán Mills and Captain Carlos Piderit and the Japanese Morita repeated the ascent.