Pennsylvania microurchin?

[Bonehunter]

I put this on the general forum as well, but this is probably more appropriate!!

In my search for conodonts in Pennsylvanian stark shale (between Winterset and Bethany falls limestone) I routinely find concretions/nodules-most are powdery but sometimes i find teeth and other microfossils. Well much to my surprise, upon splitting my thousanth shale, I found a 1cm nodule, and within it, this apparent micro sea urchin-one of two in the nodule. From spine to spine (7:00-1:00) it measures just under 2mm in diameter

     I am refining my photog techniques with a newly purchased leica M420, phototubes, and a sony A660 camera, which produced this nice photo of one of the conodonts. I am intrigues by these tiny urchins (if that is truly what they are! ). thoughts, comments and any hope of specific i.d. on this or the conodont appreciated!!!!! (and how this wound up in the anoxic shall layer)-wasn't a surface find contaminant, but found upon splitting shale.....so ~300million years? thanks again all!...... Bone

[Notidanodon]

Cool finds !