Another Look at Hopewell Obsidian Studies

Hatch et al. (1990) recently presented the results of research on the sources and ages of obsidian artifacts from four Hopewell sites in Illinois and Ohio. The present comment identifies ambiguities in artifact-to-source attributions that compromise the subsequent source-specific obsidian-hydration objectives of the study. Examination of obsidian-hydration rim-measurement resolution and associated error estimates, disagreements about the validity of laboratory-induced obsidian-hydration rates used in the study, and contradictions between rim measurements on the same specimens lend no support to the authors' conclusion that obsidian was conveyed into these sites throughout the entire temporal duration of Hopewell mound construction.