Would this be a bifoliate bryozoan?

[Rogue Embryo]

 

Found a couple of days ago along Lake Ontario, in Toronto:

 

 

 

 

This is a follow-up to my previous post some weeks ago:

I stand corrected about the "graptilites" part! Turns out the fossils on that rock were bifoliate bryozoan. So I'm wondering if the present specimen submitted here is also a bifoliate bryozoan. Thank you!

[Kane]

I wouldn't rule out trilobite or gastropod fragment on account of the shell texture and colour. It would be good to do some light scribing to reveal a bit more to be certain. 

[FossilDAWG]

The structure does not look like a bryozoan.  Bryozoans are colonial animals, with each individual occupying a tube, so the cross section should consist of sections through longitudinal tubes.  In biofoliate bryozoans there are two layers of tubes, one facing each way, with a plane in the middle dividing the right- and left-facing layers.

 

Your specimen does not have that structure, rather it appears to be solid.  It seems to be a section through a shell, possibly trilobite, brachiopod, or bivalve. 

 

Don

[Northern Sharks]

Looks "trilobitey" to me too, like the edge of a cheek.

[Rogue Embryo]

Thanks people for your ideas! I don't have equipment for scribing, but will do a deep dive into trilobite anatomy.

 

Cheers,

Camille