Smooth Crinoid?

[Caroboneferous]

I found this piece on the Missouri River outside of Kansas City.   There were Carboniferous fossils in the same area.  It looks like a crinoid stem, except it’s smooth?  Also, the broken ends don’t show any sort of star pattern. 
 

I was curious, any ideas?

[Dblackston]

I wonder if this could be a baculite or a echinoid spine. 

 

I am not familiar with carboniferous fossils but I saw those in our 4H guidebooks and they looked similar. Smooth tapering spines.

[Lone Hunter]

I think bacculite also.

[X-fish]

Another possibility would be a Scaphopod

[Caroboneferous]

26 minutes ago, X-fish said:

Another possibility would be a Scaphopod

That is a possibility,  the majority of fossils I’ve found at this location have been from Carboniferous limestone.    It’s on a River, but still it looks like the same Pennsylvanian era limestone. 

[DPS Ammonite]

It appears that we are looking at a mold (smooth area). The yellow area looks like recrystalized “shell”.

Edited July 12, 2021 by DPS Ammonite

[Fossildude19]

Too old for baculites.   

 

[Missourian]

Scaphopod comes to mind for me as well.

 

Another possibility is Aviculopinna, a razor clam.

[cngodles]

Im going to say orthocone cephalopod (Orthocerida).

 

It is much too narrow of an angle to be a pinnid (razor clam). There would also be more than one big layer of shell with a discernible prismatic layer on top.

 

I’d be curious what the small end looks like sharp and up close.

 

https://fossil.15656.com/catalog/search-for/Orthocerida

[cngodles]

Also, these look like a separation of some sort, which would be septal walls if it’s a cephalopod.

 

 

[Thomas.Dodson]

I'd say cephalopod. cngodles echoed my sentiment on pinnids. For scaphopods I'd expect to see visible curvature over such a long section.

[Missourian]

44 minutes ago, Thomas.Dodson said:

For scaphopods I'd expect to see visible curvature over such a long section.

 

Some of our Pennsylvanian scaphopods are quite straight, as is this Paleodentalium:

 

[Thomas.Dodson]

1 minute ago, Missourian said:

 

Some of our Pennsylvanian scaphopods are quite straight, as is this Paleodentalium:

 

Still seeing curvature in this specimen that I don't see in OP's although my eyes have been fooled by photos before. There's also the separation (as it appears anyway). 

[Missourian]

As for razor clams (Aviculopinna/Pteronites), I had this one in mind:

 

[cngodles]

I have no experience at all with scaphopods, so I can't make any sort of assessment there.

 

As for the razorclam (Pinnids), the example before my comment appears to be still buried in matrix. In the subject specimen for this thread, it appears to be an elongated oval in cross section with rounded sides. Pinnids typically will be a pointed oval in cross section, except perhaps at the base. Also, they have more inflation than the specimen.

 

I'm more confident with pinnids, as I got to spend half a day last month examining all of my specimens with a professional (more about that to come some day in the future).

 

Below is a typical cross section for a Carboniferous (Late Pennsylvanian) pinnid.

 

 

 

More than you've ever wanted to know about them:

https://fossil.15656.com/research-pages/aviculopinna/

 

 

[BobWill]

On 7/12/2021 at 9:17 PM, cngodles said:

Also, these look like a separation of some sort, which would be septal walls if it’s a cephalopod.

 

 

 

 

I agree. There would be no reason to see this segmentation on specimens of any of the other suggestions and every reason to see them on an internal mold of an orthoconic cephalopod. As @DPS Ammonite said there appears to be remains of the shell along the outer margin.