Large amounts of pumice were thrown out of the volcano at the same time as the bombs or soon after. The pumice covers most of the eastern half of the park, and fragments are scattered as far southwest as Pyramid Peak and as far northwest as Spray Park. This pumice, called layer C, is especially thick and coarse at Yakima Park and Burroughs Mountain, where it lies at the ground surface (fig. 10). Here the light-brown layer is 5-6 inches thick and consists of irregularly shaped pumice fragments as much as several inches across. Mingled with the pumice fragments are fist-sized chunks of light-gray rock that probably were simultaneously thrown out of the volcano by violent explosions. Some of these angular rocks were hurled as far as Shriner Peak, 11 miles east of Mount Rainier’s summit. [Illustration: Pumice layer C, which consists of light-brown fragments, lies at the ground surface over much of the eastern part of the park. (Fig. 10)] The eruptive period was climaxed by the building of the volcano’s present summit cone, which is at least 1,000 feet high and 1 mile across at its base. Although dwarfed by the tremendous bulk of Mount Rainier, it is a little larger than the cone of the well-known Mexican volcano Parícutin that appeared in 1943 and erupted until 1952. Mount Rainier’s present summit cone was built within a broad depression at the top of the main volcano that had been formed nearly 4,000 years earlier (fig. 11; see p. 40). The cone consists of a series of thin black lava flows, and its top is indented by two overlapping craters. Rocks around the craters are still warm in places, and steam vents melt caves in the summit icecap. The first climbers who reached the top of the mountain, in 1870, spent the night in one of these caves, as have many benighted climbers since. [Illustration: The snow-covered lava cone lies in a depression 1¼ miles wide at the summit of the volcano. The cone was probably built about 2,000 years ago. Liberty Cap is to the left and Point Success is to the right. The cliffs below and to the right of Liberty Cap enclose Sunset Amphitheater. (Fig. 11)]