The author reports systematic examinations of coastal shell-heaps along the Maine and Massachusetts shores, describing their locations, size, layered structure, and contents — mainly clam, quahog, scallop, and mussel shells with animal bones and stone, bone, and antler implements — and notes stratigraphic evidence of multiple occupations and soil formation between deposits. Excavation methods, species lists, charcoal and hearth remains, and the preservation role of shells for bones and fragile artifacts are documented, with site-to-site comparisons and discussion of what the deposits indicate about seasonal or permanent shore-based subsistence and tool use by earlier local populations.