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Hi, I'd appreciate some help with this one, it's got me completely foxed and I can't find anything similar online. The matrix is a mudstone, it was a loose rock in a stream, the rocks in the area are all Brigantian (Upper Visean) - Carboniferous Cyclothem deposits (Northumberland, UK). There were 3 of these, all about an inch long, oval shaped, but fairly irregular, with faint radial lines/corrugations from a central 'spine'. They are three dimensional about a quarter of an inch thick. Small spiriferid brachiopod shell fragments in the same rock are undeformed, so I think the irregular shape is original. They remind me of small jellyfish but I think that's highly unlikely to have fossilised so I'm guessing some sort of trace fossil. All three are similar in shape and size so I'm wondering if there's a specific name for these, and whether it's known sort of creature made them?

 

Cheers

 

Steve

Sample 1 front.JPG

Sample 2 (cast).JPG

Sample 2 and 3.jpg

Sample 1 back.jpg

Sample 1 edge-on.JPG

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Welcome to TFF!

My first thought is a sponge of some sort. 

But wait for others to reply.

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Are mud bubbles (or other blobs of preserved mud) a possibility? Now that I think about it I think I've seen something like this in my collection, late Carboniferous. Let me go take a look...

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Ahh yes, it's actually on my upload to IPFOTM, it's hard to see though and has been broken, had to be glued back together. Don't know what it is though....

its a about a centimeter or two from a horsetail root, but I dont think that has anything to do with it.

image.jpg

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These are pseudofossils; nodules slickensided by burial compaction: Guilielmites

 

IMG.thumb.jpg.a8fc65d8b8715f390f6d17e7d7b5940b.jpg

  • I found this Informative 13
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I agree with piranha.

I've found exactly the same things in Brigantian shales in Co. Durham, fooled me for a while. :)

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Just learned something new :)

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vide("see") "fossil hunting trips,Turimetta headland",on this very same forum

The Byrnes/Karaolis PDF I couldn't find.

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I find these all the time in shale around here. They are very annoying :ank:

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Are these restricted to carboniferous rocks? I wonder why...

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Wow, that's a fantastic response, thanks everyone for ideas and particularly piranha, I've never come across these Guilielmites before, great to learn something new! 

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13 hours ago, piranha said:

These are pseudofossils; nodules slickensided by burial compaction: Guilielmites

 

IMG.thumb.jpg.a8fc65d8b8715f390f6d17e7d7b5940b.jpg

Thanks Piranha, I hadn't heard of this process but it makes perfect sense. 

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6 hours ago, WhodamanHD said:

Are these restricted to carboniferous rocks? I wonder why...

No, they aren't. We have found them in Permian - Triassic rocks around here (Sydney). Nowhere else that I can remember? o.O

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3 hours ago, Foozil said:

No, they aren't. We have found them in Permian - Triassic rocks around here (Sydney). Nowhere else that I can remember? o.O

Still makes me wonder. What's the consistent factors between pennsyvanian of Pennsylvania, carboniferous of U.K., and Permian to Triassic rocks of Australia. And why aren't there slickensided nodules in rocks of all ages? I don't know, seems suspicious to me....

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Ya learn something new everyday.

 

RB

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