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

5.4.1.2.11: Medium circular biface (see Figure 5.2 #20). This type was manufactured by
direct percussion. It is 8 cm to 12 cm in width. A thick, diamond-shaped cross section
was the desired result of the reduction process.
These tools are common in the Piedras Negras sample. The term “circular” is
somewhat of a misnomer because while some of these artifacts are circular, most are
better described as oval-shaped. Nevertheless, “oval” has been used to refer to various
kinds of celtiform bifaces elsewhere (e.g., Shafer and Hester 1983), and is thus avoided
here to reduce confusion in the present typology. These bifaces were made from blanks
prepared specifically for the production of circular bifaces. A great number of uses have
been proposed for these tools (see Willey 1972:160). Macrovisual analyses of circular
bifaces from Piedras Negras suggest that they may have been used for chopping, cutting,
scraping, hammering, and pecking, probably for architectural blocks and metates made of
limestone. The term general utility biface created by Willey (1972:157) seems to fit well
here as a functional description of these tools. They are made of the same coarse-grained
materials as the thick, celtiform-biface types, and a thin cross section was not a desired
trait of the finished product. It is sometimes possible to distinguish this form from
resharpened, celtiform bifaces by identifying incongruous flaking patterns on one end of
the tool.
5.4.1.2.12: Medium and small circular uniface (see Figure 5.2 #21 and #36). These types
were manufactured by direct percussion, but on only one face of the tool. The dorsal
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