Mazon Creek ID

[Herb]

An unknown I found at Braidwood, IL, Mazon Creek material. Forgot scale but about 2" wide and 1" long. It was in a marine area.

[Innocentx]

Nice, Herb. Looks like a squashed or desiccated worm.

Hope you get better ID than what I've given. 

[Wrangellian]

Interesting! It's very robust for a worm... Must be at least a worm tube, if not something like a scaphopod or orthocone nautiloid...?

@RCFossils   @Nimravis

[Nimravis]

This one has me stumped- from what I can make out in the picture, it does look segmented and looks like a casing or a straight cephalopod,  though I never seen one that color. 

 

Too bad it was found opened and exposed exposed to the elements.

 

RC was already tagged, I will tag @fossilized6s and @Rob Russell.

[Tidgy's Dad]

Very interesting. 

Clearly segmented and reminds me of an orthoconic nautiloid, but there are at least three what look like fat legs. Maybe bits of segment that have been broken off. 

If it's a nautiloid, and it does taper, then that would be the living chamber on the right. 

[fossilized6s]

It does look like a compressed cephalopod. They are rare from the Francis Creek shale, but not unheard of. 

 

RCF or @fiddlehead will know

[Rob Russell]

I saw Herbs post on FB, and wondered if it was a cephalopod, also. Soft bodied preservation looks different, IMO.  So that rules out a worm to me. It’s a cool piece whatever it is. I hope Rob, or Jack, weigh in. 

I find it intriguing how the critter wasn’t fully encapsulated by the concretion, and projects out of the side.  

[Wrangellian]

Maybe the immature end had broken off (as apparently sometimes happens with our heteromorph ammonites in the Mesozoic)? On the other hand, we also find concretions that don't fully encapsulate the fossil. I've got baculites and other ammonites that have a concretionary 'blob' stuck on part of it, the rest being exposed. Your Mazon nodules are found loose, long after they've been exhumed and dumped, right? Maybe that tapered end existed at one time (extending out of the concretion) but has long since broken off.

[RCFossils]

Interesting piece!

My guess is that it is some type of plant material.

The preservation does not look right for it to be a cephalopod

[hndmarshall]

I am in no way an expert but I did find something that may be close?....https://en.wikipedia.org/wiki/Pikaia

 

[Wrangellian]

12 hours ago, fossilized6s said:

It does look like a compressed cephalopod. They are rare from the Francis Creek shale, but not unheard of. 

 

RCF or @fiddlehead will know

 

1 hour ago, RCFossils said:

Interesting piece!

My guess is that it is some type of plant material.

The preservation does not look right for it to be a cephalopod

Have you guys seen cephs from Mazon before? I've never seen one so I have nothing to go by as to whether it "looks right" for a Mazon ceph.

However, I don't know if color is a clear indicator of taxonomy: worm tubes can be preserved in black, for instance Sphenothallus and Lecthaylus, and around here in the Cretaceous we get black-shelled ammonites (and not far away, white ones - preservation varies white a bit within a moderate-sized area).

Lecthaylus (Silurian):

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