Jurassica

Mystery Cretaceous Critters

29 posts in this topic

Massadona, CO, 1 mile east of County Shop, south of Skull Creek Monocline.

Mancos Group, main body (Kmm)

Upper cretaceous

We (myself and barkerj) found these mystery bits of what appears to be chertified flora, or fauna? Any ideas what this could be?

IMGP0324.JPG

IMGP0319.JPG

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IMGP0314.JPG

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ummmm, gosh; no idea! :unsure:

The corrugated edges of the latter examples remind me of the hinge margins on bivalves...

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you might also consider examining geological phenomena such as styolites and slickensides as potential causation when patterns don't seem to match fossils of which you're aware.

just sayin'...

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you might also consider examining geological phenomena such as styolites and slickensides as potential causation when patterns don't seem to match fossils of which you're aware.

just sayin'...

What they said ^^^

and a reference to the geology.

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Jurassica.... I can see why you thought it could be plant... Very strange, fractured in the pattern of a Cyclopteris... :)

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styolites and slickenside

Interesting idea. Maybe the sliding and friction between two layers of mud could have caused one layer to roll over on top of its self and then broken off in a leaving a corrugated edge. That would explain why the cross section doesn't look like what you would expect of a plant or shelled animal. I like it. In addition, the kmm blurb on the geologic map does not mention this formation being fossiliferous.

Edited by barkerj

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Those are bits and pieces from clams.

We see them all the time here in CO (and KS) in the Cretaceous. Sometimes they are measured in meters instead of feet. :)

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If you find out what the bottom two photos are, I'd like to know too, as I find quite a bit of it too in the Cody/Pierre shale. The second photo I would think are parts of crab legs, watch closely because occasionally you'll find a claw (I have several). Top photo, I find these also, I always think pseudo fossils.

Jim

Old Dead Things

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If you find out what the bottom two photos are, I'd like to know too, as I find quite a bit of it too in the Cody/Pierre shale. The second photo I would think are parts of crab legs, watch closely because occasionally you'll find a claw (I have several). Top photo, I find these also, I always think pseudo fossils.

Jim

Old Dead Things

The bottom two photos show the edge where the top and bottom of the clam shell comes together (sorry, I don't know the terminology).

The top photo most likely shows pieces from the same general area of the clam, but not sure without seeing more of the other sides.

It's all been replaced with something that seems fiberous, and, if cracked or gouged or smashed just right, can smell like sulphur or eggs or natural gas (which, I know, has no natural odor).

The middle photo (photo #2 I guess) is most likely the same thing....just showing the other sides....I'm pretty sure that I can see those ridges peeking around the edges of some of those pieces.

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Hmmm, the plot thickens. Do you guys have any photos of said clams or crab legs that I can compare to these specimens? And if it is a clam bit, how can it be so long and skinny? I was sure it was some type of stem from an aquatic plant. Although I did see a fossil crab and was excited about the similar shape and striations.

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Do you guys have any photos of said clams ...that I can compare to these specimens?

You can see photos of the full-sized organisms on the page I linked just above.

And if it is a clam bit, how can it be so long and skinny?

As I said earlier, these clams can be very large and are sometimes measured in meters instead of feet.

Think of it....you could take almost any tiny chunk of one of those kinds of clams and still have a piece the size of your leg and not know it came from a clam if you didn't already know that there were clams that big and what they look like.

As for skinny-ness....the only thing I can say is that that's just how they break apart.....into lots of tiny pieces....but the edges tend to stick together better. So, you can end up with a long, skinny section of the edge of one of these things, and if you have never seen them in context before, you can start imagining all kinds of things.

I was sure it was some type of stem from an aquatic plant. Although I did see a fossil crab and was excited about the similar shape and striations.

I'm not saying, without exception, that everything in your photos is from these clams, but most of those pieces definitely are.

The only ones I can't say for sure on are the ones that aren't clear enough, or I jsut haven't seen them up close yet.

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Guaranteed those are pieces of large Inoceremus clams. We find those all the time in Kansas. Wish I had a dollar for every one I picked up thinking it was a fish jaw!

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I can't tell which pictures of anything suggested is supposed to look like those last ones. I found one in POC Monday and fossiladdict thought she knew what they were but I forget what she said. I have lots of bivalves with hinges showing and none of them come close to looking like this with the flat layer of calcite perpendicular to the groovy part. I'm not saying you're wrong about the inoceremids just like to see a picture similar to these.

Edited by BobWill

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Here is a field shot of a big Inoceremus showing some of the structure you see in the first photos.

http://oceansofkansas.com/Invertebrates/v_grand6.jpg

Here is another shot where you can see the "teeth" of the hinge. Look at the lower left side of this photo. That's what you see in the bottom photo of the samples in question.

http://oceansofkansas.com/Invertebrates/v_grand3.jpg

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Im beginning to see the resemblance to the inoceramus, not only in the fibrous structure of the preservation but also the tooth-like fringes of the shell.

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Here is a field shot of a big Inoceremus showing some of the structure you see in the first photos.

http://oceansofkansas.com/Invertebrates/v_grand6.jpg

Here is another shot where you can see the "teeth" of the hinge. Look at the lower left side of this photo. That's what you see in the bottom photo of the samples in question.

http://oceansofkansas.com/Invertebrates/v_grand3.jpg

Doh! :P

Both of those photos are from the page which I linked to above (about 8-10" down the page on the left side).

Guess I figured posting the link to the page would be enough and everyone interested would go there and check it out.....sorry...I probably should just go ahead and post the relevant images here in situations like that (along with a link to the page they came from). Actually, I normally do try to do that, but I've been quite busy today.

Good job, Xiph.

I guess while I'm at it, I'll add this from that page...

"In cross section, these shells are composed of prismatic (calcitic) crystals."

...and a pic...

prisms.jpg

.

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For anyone who was confused. All four pictures show the same objects just from different angles.

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For anyone who was confused. All four pictures show the same objects just from different angles.

Aha...I suspected this much.

So, they're all clam pieces then. :)

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hmmm, an inoceramid with a thyroid condition, you say? that was my second thought....

:unsure:

<running away in a zig-zag pattern so as to remain inconsistent and unpredictable>

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hmmm, an inoceramid with a thyroid condition, you say? that was my second thought....

:unsure:

<running away in a zig-zag pattern so as to remain inconsistent and unpredictable>

...oh, you mean because they're so huge?

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Doh! :P

Both of those photos are from the page which I linked to above (about 8-10" down the page on the left side).

Guess I figured posting the link to the page would be enough and everyone interested would go there and check it out.....sorry...I probably should just go ahead and post the relevant images here in situations like that (along with a link to the page they came from). Actually, I normally do try to do that, but I've been quite busy today.

Good job, Xiph.

I guess while I'm at it, I'll add this from that page...

"In cross section, these shells are composed of prismatic (calcitic) crystals."

...and a pic...

prisms.jpg

.

Yes this picture of the prismatic crystals looks exactly like the piece I found at POC. Thanks for clearing that up. I never doubted your opinion, it's just my tiny brain having trouble telling how the hinges matched up with this crystal material since I've only ever seen broken pieces of these.

Edited by BobWill

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First let me preface my next statements with this statement. "I have been wrong more times than I have been right." That said I took my samples (of pictures 3 and 4(bottom two)) up to the Tate Museum this afternoon. JP and Russ have both concluded that they are parts of an inoceramus clam, but kept them to do a little more research. Looking at a cross section of mine also showed I was incorrect about photo one. :blush:

The second picture I tentatively identified as a crab leg. Unfortunately all my specimens are with Neil Larson of Black Hills Institute so no pictures for now, but when he is done with them I will post pictures that will show why I thought as I did.

Great finds and keep posting those pictures.

Jim

Old Dead Things

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...oh, you mean because they're so huge?

not sure. i might have been trying to be funny again. i never really know with me...

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First let me preface my next statements with this statement. "I have been wrong more times than I have been right." That said I took my samples (of pictures 3 and 4(bottom two)) up to the Tate Museum this afternoon. JP and Russ have both concluded that they are parts of an inoceramus clam, but kept them to do a little more research. Looking at a cross section of mine also showed I was incorrect about photo one. :blush:

The second picture I tentatively identified as a crab leg. Unfortunately all my specimens are with Neil Larson of Black Hills Institute so no pictures for now, but when he is done with them I will post pictures that will show why I thought as I did.

Great finds and keep posting those pictures.

Jim

Old Dead Things

Oh, I thought the second picture was the back sides of the last two, which now makes that tiny brain of mine finally see that the first picture is of the ends of the same fossils :wacko: ...Did I finally get it right jurassica?

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