Curious microfossil for id

[Brian James Maguire]

This was found in the Carboniferous limestone of the Malahide formation , east coast Dublin Ireland,  curious as to what it could be , theres quite a bit of bryozoan in the same stone, i took photo with a microscope 

[Baking Geologist]

My brain immediately goes to some sort of echinoid part in cross section.  I don’t think it’s a piece of crinoid columnal.