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AJ58

Some have ID these as horn corals.My argument with that is no sign of septa. the closest I came up with is Rousseauspira from Ordovician of Alaska and California. but those specimens are tiny  compared to mine. 

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ynot

Welcome to TFF!

These look like sponges to Me, but wait for others to chime in.

 

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Tidgy's Dad

I agree with Tony, these are surely sponges. 

They are rather wonderful. :)

Rugose corals didn't appear til the Middle Ordovician, so if these are Lower Ordovician, they must be sponges, i would have thought. 

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AJ58

Maybe Ceratopeas big Brother.I have a large collection of Ceratopea  .The biggest one is only 1 inch.And the makeup is not the  same.    

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Fossildude19
2 hours ago, AJ58 said:

Maybe Ceratopeas big Brother.I have a large collection of Ceratopea  .The biggest one is only 1 inch.And the makeup is not the  same.    

 

Hmm. I see what you mean.  :headscratch:

I am not seeing the same type of growth lines in yours that I see in the others posted here.:zzzzscratchchin:

I3Mho5Y.jpg

   

Maybe sponge is something to investigate.  :unsure: 

Or, perhaps Monoplacophoran?   

 

 

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DPS Ammonite

Here is a USGS paper by about Ceratopea opurcula. The Lower Ordovician Gastropoda Ceratopea. by Yochelson. Geological Survey Professional Paper 294-H.

 

In the paper, opurcula are up to 46mm or 1.8 inches in maximum dimension which is short of the ones shown by the OP (~ 2.8 inches).

 

Based on variations of opurcula we should still consider opurcula even if there are problems with size. We need to see how large Ceratopea get to see how large their opurcula might be.

 

See sample plate.

Link

B0A5820A-E20B-4D37-87C0-78CA2D610C28.png

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FossilDAWG

We may also consider the possibility that these fossils are siphuncles of pilocerid nautiloids, possibly Bisonoceras or something similar.  Some nautiloids are represented in the fossil record mainly (or entirely) by their massive siphuncles, with the fragile septa, external shell, and living chamber rarely or never preserved.  

 

Don

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AJ58

Has someone looked into Rousseauspira;A new gastropod operculum from the Ordovician of Alaska and California? 

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abyssunder
12 minutes ago, AJ58 said:

Has someone looked into Rousseauspira;A new gastropod operculum from the Ordovician of Alaska and California? 

Yes, after you said that. :)

pdf

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FossilDAWG

Thanks Scott! :dinothumb: That is just what I was thinking of.

 

Don

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Fossildude19

Great detective work, Scott!   :1-SlapHands_zpsbb015b76:

Well done, sir.

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AJ58

Siphuncle ; This is exactly the fossil that I have. Thank you.Your knowledge of fossils is amazing.Do you know what age these are?  

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FossilDAWG

"Ozarkian" and "Canadian" are old terms for the Lower Ordovician, which agrees with the age you indicated in the tags.

 

Don

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AJ58

Thank You.I am glad I was right about the age.I have not been to the site that I find these at in years.Its only walking distance from my house.Since then we have had a 1000 year and a 500 year flood so I am planning a fossil hunting trip soon. there should plenty to pick up. 

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