Peak 4151, South Face. Mt. Corcoran consists of four widely separated summits along the Sierra crest. The southernmost peak, a.k.a. Peak 4151, presents a striking sight in the upper reaches of Tuttle Creek’s south fork. The south face rises steeply for more than 1,000 feet across the drainage from Mt. Langley. On the Fourth of July, Bart O’Brien and I spent a great day climbing a system of corners and cracks on the right edge of the wall. Starting with a chimney in a large dihedral, the route unfolded with one delightful pitch after another. Most were in the 5.8/5.9 range, with a few harder sections. We cut left about halfway up to avoid an ominous, overhanging offwidth. Higher, we angled back right into more steep cracks and corners. After 11 pitches of crisp, shining rock (IV 5.10a), we scrambled onto the summit ridge.