This collection consists of correspondence, journals,field notes, and miscellaneous materials of Harry S. Ladd documenting his work in Tonga, Fiji, Palau, Hawaii, and Midway atoll. Materials document work 1924 - 1980. Correspondence documents work with Yoshio Kondo about fossiliferous rock collected by Kondo on Eua ['Eua], Tongo, in 1967. The material, processed by Ladd and others at the U.S. National Museum, contained fossil brachiopods, Foraminifera, and other marine invertebrates. Field notes and journals cover field work conducted in the reefs and interior territory of Fiji, Palau, Hawaii, and Midway atoll.