Paleozoic Fish Bone, Cartilage, Wood?

[cngodles]

I found this piece on Friday. I thought it was wood, hammered it out, collected it in a tiny bin, and took it home. Saturday evening I put it under the scope and was surprised to see the texture. I've collected wood before and the grains are typically tighter. It also looks very similar to recovered Petalodus or fish root material I've seen. This deposit has a lot of different shark teeth, at least four unique genera are present. The limestone has the characteristics of a dynamic wash, where a lot of material was gathered and deposited quickly. Not that it helps a lot.

 

I've never found shark bone or cartilage, so I don't know exactly what to look for.

 

Scale bar = 5 mm.