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Post by Joe Botting on Jul 20, 2009 2:58:26 GMT -5
Hi All, Just thought we should let you know that the oldest rocks in the Builth Inlier, the Camnant Mudstones, are more interesting than has been thought. There are quite a few little exposures of these silty mudstones with trilobites and graptolites in, but until now, nothing really exciting had come out of them except for John Cope's bivalve fauna in transported sandstone beds at Camnant. We had assumed that this is because the rocks aren't yet heavily affected by the volcanoes, and so there's little scope for rapid burial or odd mineralisation... Now, for the first time, we've got an extensive locality in the form of a new farm quarry, and it's amazing. Palaeoscolecids, sponges, echinoderms, unmineralised arthropods, and probable soft tissue in at least three specimens - including some internal anatomy of a trilobite! It's early days so far, and as yet we're just getting bits and pieces, but it is a seriously promising site... We'll post a few photos soon, but this is just a newsflash - there's more to this formation than meets the eye, I'm glad to say!
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solius
I know what fossils are!
Posts: 44
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Post by solius on Jul 23, 2009 4:26:42 GMT -5
Awaiting, in eager anticipation, the photos and papers.
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Post by hallucygenia on Jul 23, 2009 12:44:38 GMT -5
Might be a while - we've barely started! Some very interesting stuff, though. We're hoping to go back in a couple of months to do some more collecting.
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Post by Joe Botting on Jul 23, 2009 15:37:58 GMT -5
Here are some photos, though: A sponge, Choiaella - a new species, almost certainly, and a tiny one at about 3 mm across. These are normally restricted to major sites with exceptional preservation (e.g. Chengjiang). This is the carapcae of bivalved arthropod closely resembling the Burgess Shale and Chengjiang genus Isoxys. Never bfeore recorded after the Cambrian, so it's an interesting find. A baby Ogyginus corndensis with a difference... Despite being only 5 mm long, that appears to be its stomach preserved in its "head". It's a crystalline infilling of something, and that's where it kept its stomach, so there aren't many other options. Needless to say, this would be rather exciting. ;D And finally for now, an undescribed arthropod. Possibly crustacean, possibly something else. It's small (about 4 mm), and rather odd, but seems to have had a carapace at the head end, some segments, then an impressive tail with telson. Might get some more photographed as well if anyone's interested?
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Post by cerredwen on Jul 24, 2009 16:10:17 GMT -5
Hmm...move aside China and Canada: Wales is obviously where it's at! If you guys need any willing volunteers let us know!
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Post by Joe Botting on Jul 24, 2009 16:23:36 GMT -5
We're always glad of willing volunteers - don't forget to bring biscuits! Wales has been seriously neglected in the recent decades, but it's safe to say that its fossils are much more interesting than people generally think...
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Post by reighan on Jul 26, 2009 18:02:26 GMT -5
Very interested!
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Post by Joe Botting on Jul 27, 2009 15:12:45 GMT -5
Oh alright, you've twisted my arm... I'll see what else I can rustle up!
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Post by Joe Botting on Aug 1, 2009 16:04:38 GMT -5
Alright, then... First a bit of palaeoscolecid cuticle: It doesn't look that exciting, but these are rare things. Excluding the Builth Inlier, I know of four localities in the UK, three of them with only one specimen. We've got six specimens so far from this site, and it's looking like being dozens of them. In close-up, it looks like this: The plates are about 0.02mm across, which is why we're going to need something a lot more powerful to show these things at their best... And something completely different - a cornute: It's very different to any we've seen before, although not all that well preserved. It's about 4 mm tall, if I remmeber right, but it's enough to see the very rounded shape, which is similar to some Ordovician cornutes I've seen in Morocco. And finally, our big problem - an echinoderm, but not as we know it. And we ought to know it. It partly resembles a group of cystoids called placocystitids, and partly resembles the cinctans (a bizarre early group that no-one is sure what to do with). Sadly, it's not right for either, and appears to be missing a stalk or appendage, or something... as it stands (and we have five of them), I'm not sure what class to put it in. And for an echinoderm specialist, that is seriously wibbly. ;D
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Post by hallucygenia on Aug 8, 2009 2:45:33 GMT -5
With the 'cinctan' (for want of a better word): are we sure we're looking at echinoderm? Could we be looking at something with a lumpy texture, rather than plates? (I know, the fossils are upstairs and I could just go and have a look - but it's nice to have a bit of discussion!)
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Post by Joe Botting on Aug 9, 2009 12:40:03 GMT -5
Well.... not entirely sure, to be fair. However, it definitely does seem to be a plated structure, and it's certainly not regularly segmented as an arthropod should be. It could perhaps be "quilted" rather than plated, but that would be even stranger (Ediacarans, anyone?). I suppose the preservation is also potentially misleading, given they're all replaced by pyrite, as it *could* be something soft-bodied... but that would be even more surprising, to me...
Even assuming something potentially soft-bodied or iwth different mineralisation, what other group could it be? Ideas on a postcard, please...
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solius
I know what fossils are!
Posts: 44
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Post by solius on Aug 18, 2009 4:22:50 GMT -5
Just an amateur. And I have only seen soft tissue stuff once, but(forgive my ignorance) why echinoderm, and not some kind of polychaete?
<curious>
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Post by Joe Botting on Aug 18, 2009 15:04:09 GMT -5
Nice thought - and you're right, if it's soft tissue, then all sorts of options come into the equation. In this case, though, note that the central area is irregularly plated, with no segmentation running across. Also, there is no imbrication of the plates - they're just boundaries on an other wise flat surface, and with polygonal junctions. Whether soft-bodied or not (and I suspect not), the thing was plated in the same sort of way as an echinoderm theca - and I can't come up with any other groups like that at the moment... it's not waternight as an argument, but it's a start. With any luck we'll be able to get one of them thin-sectioned, and see if there's any relict stereom. p.s. Around here, "just an amateur" status carries a lot of weight!
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Post by Joe Botting on Aug 18, 2009 15:09:55 GMT -5
Updates on the Wern beasties... The bad news is that the "undescribed arthropod" has turned out to be nothing of the sort! Alas, it appears instead to be a weirdly mineralised and somewhat distorted partial lower lamella (bottom half of fringe) of a trinucleid. Ouch. But hey - that's science for you! On more interesting news, we've analysed the stuff in the trilobite's "stomach". Turns out it's not calcite after all. Quartz, then, you ask? Nothing of the sort. This stuff is barium sulphate, and what it's doing there we have not the faintest idea. Where the barium came from is a a mystery. Basically, the plot thickens... but if nothing else, it shows that something very interesting indeed was going on inside the little beastie. It also means we can X-ray the thing to see if there is any more of the digestive system preserved.
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Post by hallucygenia on Aug 22, 2009 3:45:22 GMT -5
The other thing we need to do with the trilobite is to see how common the baryte is - is this a one-off specimen, or is this preservation common at this site? Articulated trilobites are fairly common, so if this was happening often we should get more of them...
What I really want to know is where the barium came from - there are various ash bands in the quarry, so that might be a possibility - but it still has to get into the trilobite somehow!
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