Is this a trilobite?

[Stilitano]

Greetings!

I found this imprint on a large piece of what I assume is coal on the beach in SC. 

Sand was dredged from offshore  to replenish the beach, and there are fossilized teeth of deer, mammoth, mastodon, tapir, megalodons, etc.  Nothing nearly as old as a trilobite.

A lot of heavy coal pieces were on the beach after hurricane Matthew and I found this imprint on one of them.  Can anyone tell from this image if it's a nothing or a something?

(Pics were tricky, but can take more if needed and if image file too big I can squish it down.) 

--Stilitano

[Stilitano]

Same pic, closer up.

[tmaier]

I'm guessing it is a plant fossil, but can't pin it to anything in particular. I see other imprints that look like plant fossils right next to it, so... guilt by association.

[Stilitano]

Thank you.  I was hoping the surrounding imprints might give a clue.  But definitely sad it's not a trilobite! 

[tmaier]

It's likely a fossil from the Pennsylvanian period, 300 million years old. Definately worth picking up, and not to be sad about! :)

[Stilitano]

Wow.  I think the oldest fossil I have so far is from the Miocene; so I would be very happy to have something from that period!

[Stilitano]

On your advice, tmaier, looking at plants, perhaps calamite?  Maybe someone else will chime in on my not trilobite.

Thank you again!

[tmaier]

It might be a Calamites. Those stalks had ribbing on the inside and on the outside. The inside cast is called a pith cast.

But it also might be the internal cast of a Cordaites, called a Artisia.

https://steurh.home.xs4all.nl/engcord/ecordai.html

A weird thing about these fossil plants is that the parts are given different classification names, so the leaves have one name, the roots another classification name, the trunk a different name, etc. So it looks like one plant is actually five different species. It's a tradition to do that.

[abyssunder]

I think, there could be conchoidal fractures in the upper part of the matrix, which could  suggest that is chertish or coalish. Could be just a geological feature resembling shrinkage/hackle fringe patterns in a conglomerate. (?), or maybe some mineral with iron contain resembling similar characters?

[tmaier]

It's a coal ball, and those are plant impressions. I've done a lot of picking in coal materials. At the top there does seem to be a precussion fracture, but the impressions are plant.

[Stilitano]

My plant knowledge is zero, so this is a valuable head start. 

Yes, there is a fracture, but the impressions are fairly detailed, distinct, and on one plane--the coal has layers you can see from the side.

I'm not a mineral person, either, but in some places the imprints have a slight edge or rim around them that make them seem like. . .well, an impression. 

I do remember looking on the forum and being surprised by the deliberate and organic looking patterns minerals can make.