Pumice flow of the 1883 Krakatau eruption occurs It at Small Rakata, Rakata and Sertung Islands, those which roughly correspond to the wall of Krakatau caldera, Indonesia. significantly differs in both mineral and chemical compositions against any other volcanic rock or ejecta of the Krakatau Group, those of which belong to Miyashiro's (1974) tholeiitic series. Meanwhile, lithic fragments of gr…