Thank you very much Fearn and Lemmy! Great information and resources. This whole topic is pretty much new to me, and really adds new dimension in understanding weapons of relatively much more recent times. I thought I might have seen those cog wheel forms before, but thought it was in something from India or Asia.
It always makes me wonder, why would these mace heads, intended for blunt force attack, have these crenallated edges on a disc? Having seen these outside this context, they almost seem like some ancient machinery (ala Indiana Jones

, so why wouldn't they, as maces, just been left smooth?
The material on trepanning is really interesting Fearn. It seems amazing that in these primitive times such 'advanced' (or perhaps daring) surgery was even attempted, and even more so that the patients often survived. I really do appreciate the great information you always find.
All very best regards,
Jim