Fig. 129—Composition of slopes at Puquiura, Vilcabamba Valley, elevation 9,000 feet (2,740 m.). The second prominent spur entering the valley on the left has a flattish top unrelated to the rock structure. Like the spurs on the right its blunt end and flat top indicate an earlier erosion cycle at a lower elevation.
Fig. 130—Inclined Paleozoic strata truncated by an undulating surface of erosion at 15,000 feet, southwest of Cuzco.
