Geodized fossils?

[TwoOaks]

I'm a newbie to The Fossil Forum.  I hike in the hilly areas of south-central Indiana (mainly Morgan, Monroe & Brown counties) whenever I get a chance and many times I end up walking the rocky creek beds looking for fossils & unusual rocks.  These creeks are rich in geodes and there is a lot of shale & limestone.  I believe that some of the unusual finds are geodized fossils.  I have several that I'd like to share with the forum to get opinions from the experts.  Attaching multiple photos (15 total: 3 groups of 5) of 4 different specimens with the first five photos showing a pair which have similarities.  Thanks in advance for any input.

[Kane]

Nice pieces! I am thinking coral for the longer one, or possibly crinoid. There is a lot of Ordovician in your area, so I defer to the locals there to provide a precise identification.

[abyssunder]

The first five pictures show geodized crinoid stems, in my opinion.

Picture from here: https://www.mindat.org/mesg-545970.html

Edited August 22, 2021 by abyssunder

[Tetradium]

1 hour ago, Kane said:

Nice pieces! I am thinking coral for the longer one, or possibly crinoid. There is a lot of Ordovician in your area, so I defer to the locals there to provide a precise identification.

The last one somehow remind me of Murex but no way. Most likely a shell of some kind. 

 

1 hour ago, Kane said:

Nice pieces! I am thinking coral for the longer one, or possibly crinoid. There is a lot of Ordovician in your area, so I defer to the locals there to provide a precise identification.

 

[Kane]

I agree with @abyssunder -- crinoidal. 

[Tidgy's Dad]

+5 for crinoidal. 

[Tetradium]

8 minutes ago, Kane said:

I agree with @abyssunder -- crinoidal. 

I'm just going to leave the last one up to you guys. Its just so unnerving how just from a picture alone makes me think so strongly of something else when its best to just go with the most common logical choices. 

[Kane]

3 minutes ago, Tetradium said:

I'm just going to leave the last one up to you guys. Its just so unnerving how just from a picture alone makes me think so strongly of something else when its best to just go with the most common logical choices. 

Identification from photos is an art and not a science. I think all of us are more than willing to entertain alternative suggestions.  

[Tetradium]

Just now, Kane said:

Identification from photos is an art and not a science. I think all of us are more than willing to entertain alternative suggestions.  

True. To me it look so strongly like a geography distorted and mineralized murex - even there "appear" to be whorls, ridges, remains of previous lips.  Then covering it mouth that look like a jingle shell (Anomina ephippium) its on. The resembles is so eerie to me. Even fossil jingle shells from Florida have a few of what I'm guessing as remains of muscle mineralized in low oxygen muck but there's so many in this picture. 

[Pumpkinhead]

In this case, the fossils are almost certainly Ordovician, which would be too old for a gastropod of that type.

 

And the op is right when he says that they're geodized- lots of mineralized critters have cavities in them in which minerals, usually carbonates or quartz, precipitate some time after the death of the organism. It's common and visually striking in most of the Paleozoic stuff I have experience with.

[Tetradium]

39 minutes ago, Pumpkinhead said:

In this case, the fossils are almost certainly Ordovician, which would be too old for a gastropod of that type.

 

And the op is right when he says that they're geodized- lots of mineralized critters have cavities in them in which minerals, usually carbonates or quartz, precipitate some time after the death of the organism. It's common and visually striking in most of the Paleozoic stuff I have experience with.

That's why I was just talking about the irony of it. A murex species found in Indiana? Naaah. 

[Tetradium]

4 minutes ago, Tetradium said:

 

 

48 minutes ago, Pumpkinhead said:

In this case, the fossils are almost certainly Ordovician, which would be too old for a gastropod of that type.

 

And the op is right when he says that they're geodized- lots of mineralized critters have cavities in them in which minerals, usually carbonates or quartz, precipitate some time after the death of the organism. It's common and visually striking in most of the Paleozoic stuff I have experience with.

You can see a modern murex species that I have. Its just a example of how sometime just looking at pictures online can fools us without knowing a huge variety of additional information like locations, formation, directions of glaciers, upriver, just to name some information. Even modern shells can be a huge headache as information tend to be sparse.

 

For example it took me 3 years to finally find a mangrove periwinkle on Atlantic side of Florida. All the books, online information says they are found where mangroves are, meaning suppose 2/3 of Florida coasts. But when I finally found them I could see what was wrong with the information - they only live in colonies and rarely ventures far from them and they along with certain species of bivalves and gastropods only live along inlets on Atlantic side for a certain distance - beyond that its what I called bubble shell zone (the genus is actually closely related to freshwater gastropods and mostly only found in brackish water) then the most remote sections of mangroves only had one species of fiddle crabs - no shells of any kinds because temperature, how much salt is in them, low oxygen is too much even for shells to try to survive in them.  

[connorp]

2 hours ago, Pumpkinhead said:

In this case, the fossils are almost certainly Ordovician, which would be too old for a gastropod of that type.

These are Mississippian, not Ordovician.

[TwoOaks]

Thank you everybody for your input!

[Rubykicks]

Those are pretty!  I've found so many geodized fossils like that near Brown County. The ones I find are usually pink and pale blue. Almost like opal, but I'm not really sure, maybe chalcedony.  Anyway, cool finds!

[Harry Pristis]

 

Definitely Mississippian in age.  These are pseudomorphs after crinoids, et al.