Samples of inshore marine shell species (various taxa, see description below) were collected from controlled excavation of ceramic-bearing strata of two archaeologic sites in the Manu'a Island group, American Samoa. Located on the closely adjacent islands of Ta'u and Ofu (14° 14’ 30” S, 169° 30’ 40” E and 14° 10’ 55” S, 169° 39’ 0” E, respectively), these sites represent human occupation along shorelines undergoing a parallel depositional sequence of calcareous sand dune development and concomitant seaward progradation. Our primary objective was to obtain an initial age estimate for prehistoric ceramics from eastern Samoa. On stylistic and technologic criteria, the ceramics recovered from our excavations can be classified as thick-coarse Polynesian Plainware. Based on previous studies in Western Samoa, Polynesian Plainware represents a terminal phase of prehistoric pottery manufacture in the Samoan Islands, believed to date from ca 200 bc to ad 300 (Green & Davidson, 1974).