I was given some Archimedes bryozoans and I was told they are from a Mississippian exposure somewhere in Alabama. I'm afraid that's all I know so far. They have a feature I'm not used to seeing. The only ones I have found consist of just the central axis support, or "screw."
These do not show that part at all but they have just the outer edge of the fenestrated portion exposed the whole way around the specimen like this.
Using only hand tools I started trying to expose the fronds to see if that is even possible and had some pretty good results.
I will try to either saw or sand one of them down to see if I can expose the central axis and maybe prepare the other side like I'm doing this one. I can probably manage that part okay but exposing the edges is very tedious. I may have someone with air abrasion tools see if they can't do a better job than what I am managing. @Ptychodus04 ? Want to trade some labor for a couple of these?