The Organization of Chipped-Stone Economies at Piedras Negras ...

for cylindrical cores. The edges of flat cores supplied ample amounts of usable platform
space. Pressure notching was carried out using a handheld pressure-flaker, while indirect
percussion notching probably required a small antler punch and wooden percussor. The
results of both notching techniques are wide semicircular notches that feature sharp
angles to the working surface. This pattern indicates that thinning was not of interest, and
also that the implements used to carry out the notching were thick and wide at the tip. In
eccentrics made from both notched flakes and notched cores, there is no evidence of
bifacial thinning. The notching techniques have no association with the biface-thinning
procedures used for microcrystalline-quartz tools. Some possible explanations for why
notched-core eccentrics were not worked with a fine bifacial reduction technique include:
(1) the eccentrics could have been made with great speed and a lack of care, but may
have had no mastery of bifacial technologies; (2) they could have been produced by
knappers who were proficient in blade making; (3) the thick form may have been
important to the symbolism or function of the eccentric.
6.4.3: Bifacially Worked Eccentrics
These eccentrics largely are a late phenomenon, and partially bifaced obsidian
pieces appear in Piedras Negras caches before the completely bifaced eccentrics. It is
possible that partially bifaced, obsidian blade-cores represent a technological form, which
was transitional to those that are completely worked on both faces (i.e., no remaining
blade scars on either face). Regardless, both technological types were used to create
purely symbolic types of eccentrics. Naturalistic forms do not appear to have been made
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