I found this quite recently in Ossett, West Yorkshire, UK and it is carboniferous in age. It comes from the carboniferous clay which is near to the semi sandstone but it is a bit higher up (by about 4.5m.) The only possobility I can think it is a swamp fish tooth bar section, but I'm not sure. I don't think it's a plant fossil because the lines don't run the whole way though it like a calamites fossil and the carboniferous clay formation has more ancient swamp material, like fossil swamp floor, which contains a lot of snail like animals (I think.)
Do you suggest I take it to that centre which actually looks at them when you send them or do you know what it is?
I would appriciate any replies on this one because it is very different to any other fossils which I have ever found.