Identifying Blades and Preforms of the
Paleo and Archaic periods.
by Bill Breckinridge (
This article first appeared in Issue 29 of the Newsletter of the Kansas
I hate the word "preform". I feel it interferes with our understanding of stone tools and
the lives of their makers by reinforcing a misconception common to modern people.
Modern tools are made to be job specific in their "first stage" and when they are no
longer functional for the task they are discarded. A full flint blade has the flexibility to be
modified for many tasks. And instead of being discarded when its size or other
characteristics render it unsuitable for its first use, the piece can be altered to perform
another job. Sure, you can use an old shovel for a hammer, and it may work. But mobile
hunting cultures perfected a system which combined efficiency, flexibility, and portability
in an ingenious way.
A blade can serve as a hide scraper, a butcher knife, a carving knife for wood or bone, a
straightener for weapon shafts and many other jobs. The edges would have to be dulled
before further reduction, anyway. A large blade when percussion sharpened will yield
many razor sharp flakes with a better edge than the original biface. Percussion flakes
from late paleo blades are often large enough to be made into dart points, as well. As
the original blade is narrowed and refined through use and sharpening it may be hafted
for use as a knife, lance, or spear. Further breakage and damage may result in the
piece being used as a drill or end scraper.
The word preform is often used by collectors in a disparaging way, implying a piece is
"unfinished" or difficult to classify. It is a strange reflection on modern people that we
perceive full, unused artifacts as less valuable than heavily resharpened used ones.
Careful examination of these under appreciated early stage bifaces can reveal many
clues as to their planned future use and cultural affiliation, greatly increasing our
appreciation and understanding of these often-beautiful relics. Here are some of the
things I consider when examining a blade or preform.
The material is important for many reasons. Most full pieces are found within a short
distance of the source of flint, so knowing the material lets you focus on cultures in that
geographical area. Comparison with other samples can determine whether or not the
stone has been heat-treated. Additionally some cultures show a marked preference for
certain materials, which should be considered when typing.
The outline or general shape is often a clue to the age of the piece, but cannot always
be relied on. Although certain blade shapes were clearly preferred at different times,
these shapes reappear at later times and in different areas. As the basic blade is
refined by use and sharpening it often more obviously foreshadows the diagnostic point
The cross section is a valuable clue to use and type. The importance of this
characteristic is usually underrated.
Flake patterns and the type of hammer used are major indicators. This is where the
story is written in stone, and it is way beyond the scope of this work to attempt an in
depth explanation. But it is worth noting that many times a blade is thinned before it is
notched. The location and angle of these strikes often clearly reveals the makers
intention to produce a certain type of point. Paleo bifaces are often fluted while still
being used as a unhafted knife, allowing more body in the biface to absorb the shock of
fluting and reduce the risk of breakage. All ancient blades are constructed with their
ultimate possible uses in mind. Indeed, they are veritable blueprints for the manufacture
of our familiar point types.
Large flint blades are among the most impressive of prehistoric artifacts. When studied
in context with points and tools they can be among the most enlightening, as well.