MINERALOGICAL ANALYSIS OF CERAMIC PERIOD POTTERY FROM RUMFORD FALLS, MAINE WITH COMPARISONS TO CASCO BAY CERAMIC SITES

Ceramic period pottery from the Rumford Falls sites are controlled by radiocarbon dates which demonstrates that the two sites were active between A.D. 300 and 1500. The sites are variously interpreted to represent late summer and early winter occupations. Pottery is consistent with the middle and late ceramic period pottery styles. The pots consist of two grain size fractions. The majority of the material in the vessels is clay with minor silt. This size portion of the vessels is interpreted to have been collected from varved clays which crop out in the upper Androscoggin River drainage in the vicinity of Rumford, Maine. In contrast, paste for the pots from the Casco Bay area was derived from the local glacial marine clays. X-ray diffraction of the clay and silt sized portion demonstrates that the finer grained portion of both Rumford Falls and Casco Bay pottery have similar mineralogies consisting of differing proportions of quartz, 2M1 mica, albitic plagioclase, microcline, and orthoclase. Rumford Falls thin sections demonstrate that the temper consists of non undulatory quartz, augite, microcline and albite, plus lithic grains consistent with biotite granite and diabase. Thin sections from Casco Bay sites demonstrate that the temper consists of undulatory and non undulatory quartz, microcline, oligoclase, coarse – grained muscovite and soft shell clam, plus lithic grains consistent with granite pegmatite, biotite granite, sillimanite quartz schist, calcsilicate and quartzite. The temper for Rumford Falls and Casco Bay sites was derived locally. Variations in temper within the Rumford Falls and Casco Bay sites suggest that manufacturing was not limited to a single locality, but occurred at several localities both in the upper Androscoggin River drainage and throughout the greater Casco Bay area. Mineralogical differences between the Rumford Falls and Casco Bay sites suggest that the completed pots were not transported to or from either area.