Another old fossil

[EscarpmentMary]

If you could give your opinions on this piece, they are common in Ontario, but the hole does have something weird in it as well as the shell,  collapsed perhaps?

[Jackson g]

I can't tell with the detail in the photos, but it looks like a rugose or cephalopod cast. Leaning more towards the cephalopod geuss.

[Rockwood]

Agreed. Nautiloid orthocone.

[EscarpmentMary]

Ok thank you!