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

phases, was used for the production of eccentrics. At least two residential groups, which
were distantly located from the royal acropolis, contained bipolar and irregular pressure
debitage consistent with eccentric production. Some eccentric blanks were chipped from
exhausted prismatic-blade cores, which were first broken in two segments by bipolar
percussion. These are only preliminary observations, and analysis must be conducted to
determine the true nature of the household deposits, but the pattern suggests that blade-
producing households also may have been involved in producing eccentrics for royal
rituals. A similar system of household production may have existed at Tikal (Moholy-
Nagy 1997:300).
4.3: SUMMARY
The material variability at Piedras Negras can be explained by changes in the
exchange systems through time. The Piedras Negras data do not allow for a
reconstruction of all, or even most, of these exchange relationships, but rather provide a
good starting point for future studies of regional and inter-regional exchange. It also is
clear that local materials played an important role in the development of the site through
time. The local chert source, however low in quality it may have been, likely provided
basic tool-stone for the center throughout its history. Coarse-grained cherts and
chalcedony probably were locally or regionally available to the inhabitants of Piedras
Negras. Fine flints and cherts, on the other hand, may have come from more distant
sources, such as those at Altar de Sacrificios, Cancuen, or the eastern lowlands. A more
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