Stage 10 was low risk and therefore failures from this stage are rare in the archaeological record (less than 1%). This is the only artifact I have from this stage and I would not have it except for some extreme luck (described later).
During the execution of Stage 10, the lateral edges were trimmed and the preform was narrowed as shown in the diagram of the cross-section. This trimming was done with fine pressure flaking that sometimes exceeded 20 flake scars per inch. I have seen numerous collections that contain Folsom preforms that failed during Stage 9. Often their owners believe these preforms are finished points and they don't realize that the fine retouch is missing. Most of the time, if the fine edge retouch is missing, the point was never finished.
This preform is made of petrified wood and consists of four fragments that fit together. It is from the end of Stage 10 because the pressure retouch (15 scars per inch) has been finished. However, the lateral edges were never ground (Stage 11). It was then broken with a blow to Face A. The point of impact was at the knee on the broken edge of the split midsection.
The preform was found on a featureless spot on the landscape and not in a campsite. There were no hills, ridges, low spots for water or anything else that would separate this location from any other location within a radius of a half mile. It was just pure luck that I was walking across this area and spotted a fragment of this preform.
Over a period of five (5) years and numerous visits to this site, it has yielded five fragments of the preform, four of which are in the image. The fifth piece is a fragment of the lateral edge but it does not attach to the others. Additionally, a fragment of the channel flake from face A and five (5) biface thinning flakes were found. The entire recovered assemblage was from the direct manufacture of this artifact.
I propose the following scenario: For whatever his/her reasons the point maker walked away from camp to this isolated place and began making this point. He/she created the preform and then successfully removed the channel flakes from both faces as evidenced by a fragment that fits into Face A and the preform being fluted on both sides. Next, the Post Fluting Retouch (Stage 10) was performed. Finally, instead of finishing the point by grinding the lateral edges on the proximal end (Stage 11--Marginal Polishing), this craftsmans intentionally and inexplicably destroyed the point by striking Face A while the preform was lying on an anvil.