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mar2man22

screw-shaped, chamberless cephalopod?

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mar2man22

 

Hey! I was looking for native artifacts in a neighbourhood creek when I came across what I thought was a somewhat large cephalopod fossil.

The creek is in Louisville Kentucky, leading to Floyd’s Fork. From the USGS Mapview, it looks like it’s Ordovician of the Drake’s formation. Either Bardstown member or Saluda Dolomite member.

Upon further examination, I saw that the ridges on the sides were angled very steeply. It was very covered by matrix, so I decided to get to work on it with a dremel tool.

After getting a significant amount of material off the fossil, I found that the ridges along the side were not in fact bilaterally symmetrical, and rather that these ridges went down the length of it, spiraling like they would on a screw. It is hollow, partially filled in with some softer, red stone and crystallized on the inside.  From what I can tell, it has a curve to it reminding me of cyrtoconic(?) cephalopods.

I read somewhere that cephalopods are bilaterally symmetrical, so I decided to post this here since I now don’t have any better guesses on what it is. My only other thoughts are that shark coprolites can be spiral shaped, and that it seems too smooth and hollowed to be a horn coral. My heads buzzing about this. Mum said it could be a unicorn horn :D. Due to upload limits, I will be adding a couple more photos below. I could not find any other fragments of the fossil besides this one section.

 

 

 

 

0a2b47db_25df_4c05_8_FeS92.thumb.jpg.bb6f31bee06f45c84f36488730514bbf.jpg1c354709_214a_4909_8_9amLG.thumb.jpg.a3064cfb1cf9e99534c007c0ce279e9a.jpg8e9dd3c0_0989_4e6b_9_pZS9j.thumb.jpg.15615c166656c27797138841c708194b.jpg

 

 

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mar2man22

Please pardon my prep work and note that it isn't done yet. I had to run inside while working due to severe rainfall. In the bottom two images, those indents on the upper-left side are from my dremel tool while etching away arduously. Thank you for the input! Let me know if you need to see an image from a different angle or something.13cd07d7_4bf8_40f9_a_vCmit.thumb.jpg.e362b511d02f3a1f31c4dae0427db286.jpg1721753b_179d_434e_b_59jUD.thumb.jpg.e7429a5e33da7fa8467844d7ac93fac0.jpge1d8938f_b0b8_4865_9_8s0th.thumb.jpg.ae6d9e44bcfe7ab320422964d17a0d32.jpg

 

 

please help me with this crazy thing bc I’m starting to think it’s a fossilized twiSTED CHURRO and or the burrow of some monstrous Paleozoic death worm H E L P

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FranzBernhard

What a strange object, at least for me! Thanks for sharing.

I have no idea what it is, but I hope, I am learning something new today, too.

And you did a really good job describing, preping and photographing this object. Congrats!

Franz Bernhard

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doushantuo

got a man-made vibe to it.

Cable alloys can suffer recrystallization,I believe

edit/NB: I notice your remarks on stratigraphy

Intriguing!

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KimTexan

It does look like a churro! I do t think they had those back then. :P I know nothing about the Ordovician. We don’t have any near where I live. I wonder if it could be something like a coral. I’d say a burrow, but I can’t say that I’ve ever seen a crystalline filled burrow. The burrows we have here are all casts, the infill of the burrow.

Is there a taper in diameter from one end to the other?

Very cool looking and the crystals inside are quite pretty.

@Herbis from Kentucky. Maybe he will have some thoughts. 

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KimTexan

My next guess is a trace fossil of some kind. This is an ichnofossil info slide show. I have found it useful on many occasions. Not that what you have is an ichnofossil. http://pages.geo.wvu.edu/~kammer/g231/TraceFossils.pdf

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Ludwigia

Now that is really interesting. It appears that it could be the crystallized (I'm assuming calcite) infill of something or other. But the question still remains for me: what?

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mar2man22
5 hours ago, Ludwigia said:

Now that is really interesting. It appears that it could be the crystallized (I'm assuming calcite) infill of something or other. But the question still remains for me: what?

I’m assuming calcite as well based off the white color but I still don’t know my minerals. I’m quite sure that it’s not, completely at least, man-made. It does seem to taper in diameter, increasing towards the end that is most open (with the picture). The other end is more crystal-filled, broken up, and stone-covered. I may be able to clean it up completely tomorrow to get better pictures in.

 

Theres no cable material in there but maybe it was originally vertical-standing and it was a small bore hole? Like someone could’ve drilled into the stone, and then it could have filled in with crystal and sediment? Though that seems unlikely to me, and also it looks curved, too ridged, and somewhat flattened (see how the 3rd picture, is oval-shaped)

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TqB

Fascinating specimen and I'm pretty stumped - the only spirally ridged fossils I can think of are sponges which is a very tentative stab (presumably heavily recrystallised if so). This is Helicodictya, but it's Devonian.

(From the Treatise, Part E, vol. 3)

5c30f77edb239_Screenshot2019-01-05at18_25_27.png.a1e53e624ece65acafa5b49a24f9806c.png

 

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mar2man22
1 hour ago, TqB said:

Fascinating specimen and I'm pretty stumped - the only spirally ridged fossils I can think of are sponges which is a very tentative stab (presumably heavily recrystallised if so). This is Helicodictya, but it's Devonian.

(From the Treatise, Part E, vol. 3)

5c30f77edb239_Screenshot2019-01-05at18_25_27.png.a1e53e624ece65acafa5b49a24f9806c.png

 

 

Ooooh. I started looking into sponges and I did come across something that does look similar. A stromatoporoid known as Aulacera plummeri (also from the ordovician, up in Indiana)

This article does note a couple similar stromatoporoids that also have longitudinal ridges. These look VERY similar, especially A. undulata. (It looks like some people are calling that species a sponge while this article is calling it a stromatoporoid, can someone clarify?)

 

Even Schuchert's (1919) sketch of Plummer's original specimen (from Indiana) shows the prominent spiraling longitudinal ridges that your specimens display and they occur in the type species Aplummeri Galloway & St Jean, 1957 (see illustration in J.J. Galloway's 1957 paper). There are some other species, like Aradiata and A.undulata...”

 

http://www.lakeneosho.org/More25.html

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FranzBernhard
18 hours ago, mar2man22 said:

The creek is in Louisville Kentucky, leading to Floyd’s Fork. From the USGS Mapview, it looks like it’s Ordovician of the Drake’s formation. Either Bardstown member or Saluda Dolomite member.

Ok, thats the bedrock geolgoy. How did you find the specimen? Was it a loose "rock" in the creek?

 

18 hours ago, mar2man22 said:

13cd07d7_4bf8_40f9_a_vCmit.thumb.jpg.e362b511d02f3a1f31c4dae0427db286.jpg

I suppose, the lower one of these to items is the rock that contained the item above. In other words, its the imprint or mould. The lower rock is dolomite or limestone? Was it originaly somewhat larger? How did you get the fossil out of the rock, did you need a hammer? Lot of questions...

 

5 hours ago, mar2man22 said:

I’m assuming calcite as well based off the white color

Sure these look like calcite crystals. Put a grain in vinegar and see, it it fizzes.

 

5 hours ago, mar2man22 said:

It does seem to taper in diameter, increasing towards the end that is most open (with the picture). The other end is more crystal-filled, broken up, and stone-covered.

 

5 hours ago, mar2man22 said:

Theres no cable material in there but maybe it was originally vertical-standing and it was a small bore hole? Like someone could’ve drilled into the stone, and then it could have filled in with crystal and sediment?

You are thinking very hard about this object! And I have no clue. Except a cable hyphothesis:

- piece of a cable gets encased in concrete/mortar.

- cable rusts/weathers away or/and is pulled out of its mold.

- mold gets partly filled with calcite crystals.

- @mar2man22 comes along and extracts the cast/steinkern of the cable.

...its just a (probably non-) working hypothesis...

 

Oh, the sponge/stromatoporid hypothesis sounds much better!

 

Franz Bernhard

 

 

 

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mar2man22

I just tried and yes it did fizz under vinegar. It was at first a loose bit of limestone, and the mold shown in that picture is from when at some point I used a hammer and chisel to break that piece off. Luckily I haven’t yet snapped the thing in half haha. Perhaps I’ll go back there and see if I can find more of these. Unless anyone’s got better ideas, I’m going with it being an Aulacera sponge/stromatoporoid.

 

edit: looks like Stromatoporoidea is a class of sclerosponges

 

heres the best example of A. Undulata I could find.

 

A98EB591-F5E1-4D3F-8638-C19A3A71AE2C.thumb.jpeg.0ba25e499ee1e0fd7a9dc9d1d05dc3d6.jpeg

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TqB
35 minutes ago, mar2man22 said:

I just tried and yes it did fizz under vinegar. It was at first a loose bit of limestone, and the mold shown in that picture is from when at some point I used a hammer and chisel to break that piece off. Luckily I haven’t yet snapped the thing in half haha. Perhaps I’ll go back there and see if I can find more of these. Unless anyone’s got better ideas, I’m going with it being an Aulacera sponge/stromatoporoid.

 

heres the best example of A. Undulata I could find.

 

 

That looks a very good bet. :) 

@piranha would probably have a good idea, as in this thread:

http://www.thefossilforum.com/index.php?/topic/78747-need-help-identifying/

 

(As you were wondering in a previous post, sponges (phylum Porifera) are hugely diverse and Stromatoporoidea is probably, but not definitely, one of several classes of them.)

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abyssunder

This may be a nice example of Aulacera plummeri (picture below ).

Beside the similar shape of the cross section, it has the spiraling character of the outer surface of your specimen (but not so exaggerated) with more or less rows.

 

Stromatoporoid_1B.JPG.40106b90219eb101136ca70e401ba030.JPG8e9dd3c0_0989_4e6b_9_pZS9j.jpg.ce3d4ef82cc1f9d0f9662006318af8f3.thumb.jpg.acf418d906a4997784694c015494cb06.jpg

 

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erose

Yep, A good SWAG would be the stromatoporoid genus Aulacera. Especially based on the formations (upper-most Richmond) you found it in. And with the crystallized interior it makes for a pretty dang cool specimen.

 

Excellent find.

 

ERose

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