Agnathan scale ?

[Rockwood]

For some strange reason the term 'small flake of bone' sticks in my mind as the likely evidence to be found of early fish. It came to mind when I noticed this shape under the loupe.

My dating of Ordovician is based on the fact that I find the cross sectional shapes of Prismostylus in other of the distinctive rocks. I'm fairly sure they are actually crumbs that rolled of onto the lake shore during construction of a rail bed.

It's so small I had a hard time getting a clear shot of it, but do you think there is a chance ?

[TNCollector]

I'm sorry but it looks like a water-polished chunk of oolitic limestone to me. Ordovician fish material is extremely rare.

[abyssunder]

I could see the resemblance with ooids in cross section (those ones with concentric rings), but the the bigger one of the last picture looks to have a bryozoan character. Just my thought.

 

 

A polished sphere of Oolite from Madagascar from my collection. D=35mm

 

[Rockwood]

Here is another shot taken through a magnifying glass. The pattern is fan shaped and to me looks more similar to the veins of a neuropteris leaf than a bryozoan. I'm not suggesting that's what it is, but  it's definitely not the usual concentric layers.