Plectronocerids and other neat nautiloid fossils

willsquish

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A few more plectronocerids

Hello,
Here are a few more from the same area, but a different locale. The geological map had it prehaps as the member just below the san saba member, but it was a quarry, so some stone might have been from a layer above. Hard to say. But they do look cephalopody. The first two are the same under different light. The last two are dry and wet.
 

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willsquish

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Plectronocerids

Here are a few things from the original locale. Broke some open to find them. There's also a trilobite tail found in one of the rocks of the same member. Dry and normally lit vs wet and brightly lit for the first two.
 

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willsquish

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Last plectronoceras for now

Here's the last of the ones I've found so far, more or less. The second pic has lines I see with a loupe and better light drawn in.
 

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Polishing would help.

Here's a couple of much younger ones in polished section - Moroccan orthocerid showing detail of septal necks and siphuncle and a Carboniferous actinoceratid.
 

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Architeuthoceras

Architeuthis
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Yes, polishing would help, unfortunately it would also probably destroy the fossil. So if it is being done for a taxonomic or other study where these fossils and the preparation process could be documented step by step, I would say go for it, otherwise a diagram or some means of non-destructive preparation will do. I have seen a few examples of fossils in the literature where the only remaining view of a surface is in a photo, the original ground and polished away, never to be seen again. :sad:
 

willsquish

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yeah, there's one or two I might try polishing, like the one pictured to the left of the trilobite tail, due to the fact that a, its negative is already in the other piece of rock I have, and b, it's got a really crummy surface. But as Kevin said, these are at the most like 3 to 5 mm thick specimens, so most probably wouldn't work well. The 2 palaeoceras' I saw in the actual paper were just a small section out of matrix that had been polished by erosion. other specimens of cephs from the area, they had to rub white powder in and wipe off to get white lines where depressions were, or used high light angles. I could try that sometime. I'm grateful to the lichens for doing similarly to my first specimen there. I should try a different angle photo of it. The gray septal lines on the not quite fully calcified parts of the palaeoceras show up ok with a loupe.

Here's one with a flash that sort of shows that.
 

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Architeuthoceras

Architeuthis
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Sometimes a coating of PVA or VINAC ([Poly] Vinyl Acetate) will bring out the small details or make the fossil look wet. Try it on some spare fossils before you do it to one of your good ones.
 

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