This picture shows a very close-up image of a small

area near the edge of a Fish Tail biface. The arrow is

pointing to a thinning technique that was used once-

in-awhile by ancient flintknappers in different areas

of the world, especially those who had copper tools.

The person who made this Fish Tail biface removed

part of a small "stack". The impact area is located at

the end of the arrow. It would have been done by

indirect percussion flaking. A little like using a hammer

and chisel. The ancient flintknapper who made this piece
was very skilled and maybe even a "perfectionist".