Hawaiian Islands have been and continue to be a recent locus of archaeological activity aimed at the elaboration of models of prehistoric adaptation to the island ecosystem and of continuous cultural development in isolation (Yen 1971, 1973; Kirch 1971b; Newman 1969; Sahlins, personal communication, 1972). Clearly, the initial and early stages of Polynesian occupation in the Hawaiian archipelago significantly determined the basic patterns of adaptation in a new environment, based on a set of cultural concepts and techniques for environmental exploitation and modification (cf. Yen 1973:70), transferred from a central East Polynesian homeland. However, while recently undertaking an analysis of data from early Hawaiian sites which might bear on the problem of initial adaptational modes (Kirch, ms.), the inadequate nature of the existing Hawaiian chronological framework became obvious, particularly with regard to the period prior to A.D. 1200. Although a re-analysis of the South Point (Hawaii Island) sites dates by Green (1971) and a fairly reliable series of age determinations for the Halawa Dune Site (Molokai Island; Kirch 1971a; Barrera and Kirch 1973, Table 2) have done much to clarify the picture, the ambiguous position of the Bellows Beach site (018) on Oahu Island still remained. The Bellows site, containing crucial data, was posited to be among the earliest excavated settlements in the archipelago. Four extant radiocarbon age determinations, stratigraphically inverted and with wide standard deviations, were of little use in chronologically positioning the 018 components. Fortunately, a series of eight hydration-rind age determinations made on basaltic-glass flakes from all layers of the 018 site, has now been completed. These age determinations allow the relatively precise placement of the 018 components within the temporal framework of early Hawaiian settlement. As such, they contribute to a more accurate analysis of initial modes of Polynesian adaptation to the Hawaiian ecosystem (Kirch, ms.). This paper covers the following topics: (1) a summary of the 018 site; (2) methods used in age determination;