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KimTexan

Unusual concretion.

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KimTexan

I know this is a concretion, but I think it is so cool looking. It has weathered so differently than almost any other concretion I have ever seen. Most layers of this type of material come off in a lot thicker layers. It is possible that is just how it weathered, but I am wondering if there is more to it than that. The layers are so thin and fine.

 

I found yesterday while out hunting in a new favorite spot in the Britton Formation of the Eagle Ford group in Collin county Texas with Joe AKA @Fruitbat.

 

The area I found it in is full of concretions. Many of them have fossils inside of them, but they’re a dark, brick red. The fossils are generally cepholopods, both ammonite and baculite, Inoceramus clams, other pelecypods and gastropods. 

This concretion is from a layer above the brick red concretion layer I think.

I have concretions from all over. Some are cool colors and shapes and some have fossils inside, like my Mazon fossils and also Carboniferous ones I collected in Oklahoma. Also those that I’ve collected in the North Sulfur River and Britton Formation, but this one is unique it it’s own class.

Any thoughts on it would be appreciated.

 

It seems like concretions come up so often we ought to have a concretion section on TFF. Of course most of them come up in the fossil ID section.

 

Anyone know the term for this type of concretion?

I assume it formed by repeated thin layers being added on slowly over time, which now are eroding away. Thing is I didn’t find any others like it. I’ve been to the area 3 times in the last week. Why would just one concretion be like that?

 

Side 1

A0C9B949-C297-428C-8E07-E1424C827A04.thumb.jpeg.1599f60f9368285c2075fb2d131dbe92.jpeg

 

Side 2

C57506F6-00EC-4A3F-86AF-DDFACC3D6A69.thumb.jpeg.806c3ef8ffd9d3aa54d86ede92670b9c.jpeg

One of the long edges. The other is flat and solid looking rock, kind of like the bottom end of this one.

7B6FBC64-2ABE-452C-84AA-A3AF32837680.thumb.jpeg.bc4848bc9f6ff492a0a2b1a7b7b03547.jpeg

End 149CF50BD-AEB4-4BC5-BAC8-6A84E51C35CF.thumb.jpeg.48d14204c2810e1675aebaaf68db726d.jpeg

different angle that looks a lot like wood, but must be just cool layering and weathering effects.

1FFA8E1D-A862-4915-B9B6-EC1EB64FABFE.thumb.jpeg.a2c4334d3c447f0754d438a251a2510d.jpeg

 

End 2 the typical layered concretion look.

356308AF-A0A7-4D57-A912-0D8EFCCBC8EB.thumb.jpeg.db1cfcf51b87c5d0b4ca2466bf145d79.jpeg

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Raggedy Man

I love seeing natural formations like these. Theres a road cut a few hours from my house that is covered with druzy quartz. At the right angle and time of day, it looks like a lake with the sun shimmering off the surface. Ill have to visit it soon and take a picture and post it. But, for now, here is a picture of a specimen I collected last year. Thanks for sharring!

 

20180506_135942.thumb.jpg.20a19f4837f899423ba602b558c53ab1.jpg

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Innocentx

Is the layer it came from, also this color? It reminds me a lot of fossil wood, with perhaps a pith center.

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Fruitbat

There were a few scattered blocks of material with the same yellow color but I couldn't find a specific layer that they were coming from.  I don't know right offhand if Kim did or not.  None of the material that I found had the same layered appearance.

 

-Joe

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GeschWhat

That really is beautiful - I LOVE concretions!

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abyssunder

The rings remind me of Liesegang rings .

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Darktooth
3 hours ago, GeschWhat said:

That really is beautiful - I LOVE concretions!

Said no one ever- TILL NOW!:P

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GeschWhat
17 hours ago, Darktooth said:

Said no one ever- TILL NOW!:P

Must be an acquired taste :D

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Darktooth
43 minutes ago, GeschWhat said:

Must be an acquired taste :D

Coming from you, I take that statement quite literally! :P:ighappy:

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KimTexan
On 5/6/2018 at 2:02 PM, Innocentx said:

Is the layer it came from, also this color? It reminds me a lot of fossil wood, with perhaps a pith center.

There wasn’t really a solid layer of this like there was the brick red rocks. There were actually multipul layers of the red rock. There was an orange layer There were a few in the red layer that were a lighter orange color, but those were in the same layer as the red. 

@Fruitbat I believe this is particular type of material may have been coming from a layer above the red layer, but it was mixed in with soil not the gray shale. This one was a bit higher up on the bank coming out of a wash. The yellow orange stuff must have been deposited in the soil from somewhere else into the dirt layer.

6 hours ago, GeschWhat said:

Must be an acquired taste :D

Maybe it’s a geneticly inherited thing. I’ve liked concretions a very long time. My brother and dad do too.

The more I’ve seen the more I like them.

The concretions from the area where this came are really growing on me. The place is too. Yesterday I was rinsing off the items I had collected from there and realized I have crab concretions!!!

Quite a bit of the stuff I picked up were just concretions. I couldn’t tell what was inside, but anything not totally flat seems to have fossils inside.

I was so excited to have found crab fossils. I have never found any before. I have no idea how many I found, but I know of 2 for certain and believe I have at least 3 more very likely ones. One of the 2 is missing all the appendage, but I’m still thrilled to have found it. It was the first one that helped me realize I’d found a crab. The carapace with cervical groove was visible.  Another one is missing some of them, but most of it is still inside the concretion so I can’t tell. I think I found the crabs on Wednesday and possibly 1-2 when hunting with Joe.

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Fruitbat

I had a sneaking suspicion that some of those concretions might have crabs in them.

 

-Joe

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Heteromorph

Nice concretion! I have never seen one like it before. I thought concretions were boring if they didn’t have fossils in them. Apparently they can also be enjoyed for their own sake. 

 

Would you be willing to post pictures of your crabs? I would love to see them. 

 

This installment of Dan Woehr’s fossil hunting report from July 2010 could be useful for you in identifying the crabs you found if you haven’t already. It has pictures of mutilple crabs found in the Britton formation. The Britton section starts on FIG 104.

 

FOSSIL COLLECTING REPORT July 2010

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KimTexan
46 minutes ago, Heteromorph said:

Nice concretion! I have never seen one like it before. I thought concretions were boring if they didn’t have fossils in them. Apparently they can also be enjoyed for their own sake. 

 

Would you be willing to post pictures of your crabs? I would love to see them. 

 

This installment of Dan Woehr’s fossil hunting report from July 2010 could be useful for you in identifying the crabs you found if you haven’t already. It has pictures of mutilple crabs found in the Britton formation. The Britton section starts on FIG 104.

 

FOSSIL COLLECTING REPORT July 2010

Thank you for the lead on the post. I will definitely check it out.

Will you be at the DPS meeting Wednesday night? I can bring them then if you’d like.

 

Honestly the pictures are not very telling. You have to use your imagination a bit if only seeing them by photo. They’re tiny. I think they are so cute.

I tried to capture the qualities that told me it was crab, but even I couldn’t see much of a crab from the pics I took of the one I was working on. I chose the one I thought was in the worst shape to begin on for practice. It’s taking a lot of will power to not go straight to the best looking one though.

I need to take some pics of the others that are more discernibly crabs. They are all still mostly covered in matrix.

The 5 on the lower part I’m certain are crabs. I can see anterolateral teeth thingies and lateral spines poking out a tiny bit.

The 2 on the top I’m not sure but they have a crab shape about them. I have others too I’m not sure about. One not in this pic is a concretion that is about the size and kind of the shape of a hockey puck. One of the little ones look like a tiny version of that, but has crab exposed. One of the top ones has bumps that may be anterolateral teeth. There is too much matrix on them to be sure. The matrix doesn’t come off easily either.

The center one is the most promising looking. The bottom left one does have some appendages just showing through the matrix. It’s the first one I realized was a crab yesterday when I was rinsing them off.

 

I pick up stuff and ask questions later. Most of the times it ends up being nothing. This time it was real treasure to me. I’m ready to go hunting again!!

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ynot
1 hour ago, KimTexan said:

first one I realized was a crab

Nice finds, now You know what to look for when You go back.

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Heteromorph
1 hour ago, KimTexan said:

Will you be at the DPS meeting Wednesday night? I can bring them then if you’d like.

Nice crabs! Thank you for the pictures. I will be at the DPS meeting on Wednesday night and I would love to see them in person. 

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Heteromorph

Here are some nice Ferroranina dichrous specimens (scroll down to near the bottom).

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JohnJ
13 minutes ago, Heteromorph said:

Here are some nice Ferroranina dichrous specimens (scroll down to near the bottom).

@MB is one of the best.  :D 

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KimTexan

@Heteromorph and @JohnJ do you know why they are not prepped out? Many of his other specimens have the matrix completely removed. One was kind of cleaned, but they all have a lot of matrix on them. Do you know if they are just not worth the time and effort to prep out or what?

I’m sure they are difficult to prep out well.

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Heteromorph
44 minutes ago, KimTexan said:

@Heteromorph and @JohnJ do you know why they are not prepped out? Many of his other specimens have the matrix completely removed. One was kind of cleaned, but they all have a lot of matrix on them. Do you know if they are just not worth the time and effort to prep out or what?

I’m sure they are difficult to prep out well.

I assume it would be because the F. dichrous specimens are some of the few on the webpage that still have appendages. Most of the others are just carapaces which is why they would be able to be fully prepped out. For the ones that still have legs, the matrix is needed to support them. They would fall apart if you removed too much rock. 

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JohnJ

As Heteromorph mentioned, some of these may only be a shed carapace and not practical to prep further.  Others can be incredibly flaky and may "fly away" during prep. 

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Nimravis

Cool finds Kim- Congrats.

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KimTexan
3 minutes ago, Nimravis said:

Cool finds Kim- Congrats.

Thanks.

 

@Heteromorph and @JohnJ so far at least a couple do have appendage present. 

I assume if it is a shed carapace that no appendages would be associated with it. 

 

Another question, how big do these get? As you can see the biggest nodule looks to be about 3 cm. If they get much bigger Is keep an eye out for larger crab concretions. Also, I’m curious if the hockey puck sized concretion could be a crab. If these do t get that big then I wouldn’t try working on it. It’s maybe 2.5 inches at the biggest, but I don’t see any hint of fossil yet.

I do realize that nodule size does not always directly correlate with fossil size though.

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Uncle Siphuncle

I've seen them in the 50 mm range.

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Heteromorph

Like Uncle Siphuncle said, they could get bigger. Here is a thread on a relatively large one prepped. It also has good information on this species. You can see the ruler in the first picture. 

 

Notopocorystes

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