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

ased on proximal or medial fragments it is impossible to tell the difference between a
medium-sized celtiform biface and a medium-sized laurel leaf.
These bifaces usually are made of fine microcrystalline quartzes including flint,
fine-grained cherts, and heat treated materials. They usually are quite colorful in
comparison to larger bifaces because of the wide range of materials used to make them.
They probably were reduced using direct, hard-hammer percussion, and also soft-hammer
percussion. Both lipped and nonlipped biface-thinning flakes of these sizes and colors
indicate that both types of hammers were used. However, very few antler billets have
been found that could have been effective percussion instruments for these materials.
Wood may be a likely candidate for billets since none of the bone artifacts feature
hammer-type wear-patterns. Limestone, possibly in the form of broken manos, could
have been used as percussors, but there was no conclusive way to confirm this possibility.
On the other hand, lipped biface-reduction flakes are not very common, suggesting that
chert and chalcedony hammerstones were the normal percussion implement used at
Piedras Negras. The biface was finished with a collateral pressure-flaking technique.
Pressure flaking was also used for resharpening the cutting edge, except in rare cases of
direct-percussion resharpening. If the piece was made from a flake, then the proximal end
of the flake, often a cortical platform, was retained as the proximal end of the tool. The
function of this cortical element is unknown.
5.4.1.2.2: Medium celtiform biface, thick (see Figure 5.2 #11; see Section 5.4.1.1.2 for
description).
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