Metarhyolite found on South Mountain in south-central Pennsylvania was an important raw material for stone tool manufacturing from the late Archaic to middle Woodland periods (6800 BP – 1000 BP). In the mid-Atlantic region metarhyolite appears to have been used to the near exclusion of other materials during the Transitional Period (4850 BP – 2800 BP) and was traded extensively. Our current theory suggests that quarries on South Mountain were dug to access unweathered metarhyolite which would then be removed from the upper C-horizon, since surface material weathers rather quickly. This material is most easily accessed on the ridgetops where the degraded overburden is minimized. The recently recorded Green Cabin site (36AD0569) is located mid-slope on an apparent mass-movement debris lobe, making it unique among the known metarhyolite quarrying areas in the mid-Atlantic region. The site was inventoried in 2018 and field data gathered included pit coordinate locations, pit size measurements (length, width, and depth), generalized pit morphology, the type of metarhyolite present. The Green Cabin site’s location suggests that rather than attempting to access bedrock, colluvium may have been quarried directly. These results indicate that our current model of metarhyolite use may need adjustment and that prehistoric South Mountain quarrying was more nuanced than our current understanding.

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