ID for Ordovician fossil from Wales

[dlyj0604]

I went to Gilwern Quarry in Wales hunting for trilobites lately and found some additional surprises, they are all Ordovician in age. I have no idea what the first one might be and I think the second one is a Bivalve. Could anyone help to identify these? Thanks:)

[Fossildude19]

@Tidgy's Dad  @TqB

[TqB]

Sorry, I can't identify either of them if they're Ordovician. The first looks just like a bit Carboniferous plant stem! The second doesn't have enough detail - bivalve is possible as the symmetry seems right.

[Tidgy's Dad]

I agree entirely with Tarquin as usual as it saves me having to think.

And he is usually right.

Is there any sign of internal structure at the broken end of the first one? 

[dlyj0604]

Thanks! The first one really confused me too i thought it was a fish fin by first sight. Sadly not much traces of the internal structure can be seen on the broken face of the first one since that face is  weathered. I tried to take some more photos from different angles for it. It is generally flat and seem to have a layer of ribs-like structure, and these structures extend further underneath. I'm thinking of costae on outer surface of rugose corals or some weird kind of bryozoans?

[Tidgy's Dad]

[TqB]

All I can think of is an elongate shell of some sort. There are orthoconic nautiloids with longitudinal striae. I can't make it fit a coral or bryozoan.

[dlyj0604]

I've found some relatively similar photos of Ordovician orthocones from Scotland, I think they are the most similar ones so far

(although mine seem a bit too flat?). And so I agree this might be a fragment of an orthocone! It is very different from the common kinds of orthocones and those I've seen. Thanks a lot! 

Edited May 9 by dlyj0604