A Restudy of the Reported Occurrence of Schist on Truk , Eastern Caroline Islands ' 1

Ladd (1934: 51, Fig. 6) gave a brief description of the former Melanesian continent and outlined on a map of the Pacific Ocean south of lat. 10° N. the probable eastern boundaries of several types of rocks, as well as the probable eastern boundary of the former Melanesian continent. His map, with some modifications, is reproduced as Figure 3 in this paper. In the original figure, one of the lines, designated the "metamorphicplutonic line," starts just east of Yap, extends southeastward around the Truk group, then turns abruptly south to New Ireland"and thence southeastward along the northeastern edge of the Solomon Islands. A second line, hereafter referred to as the "continental line," marks the "probable former boundary of the Melanesian continent and true structural boundary of the . Pacific Basin" and lies just east of and roughly parallels the "metamorphic-plutonic line." Both lines were drawn so as to include Truk among the continental islands and to exclude Ponape and Kusaie, high volcanic islands lying east of Truk and geologically similar to it. The inclusion of Truk among the continental islands was based on the reported occurrence of schist "on one of the islands of the group (Daly, 1916). Daly's paper, in turn, was not based on direct observation but on information JOSIAH BRIDGE2