Something From The Silurian…?

[newdog65]

out hunting the hills for trilobites, and I came across this in some silurian outcrops. Outside of trilobite, my knowledge is very limited. ANy thought on what this might be - siluarian from south east british columbia, canada.

Chris

[tmaier]

Possibly a jellyfish.

http://www.google.com/images?q=jelly+fish+fossil&btnG=Search&hl=en&gbv=1

http://ancientshore.com/2010/12/05/recognizing-fossil-jellyfish/

[JustPlainPetrified]

I am more partial in the belief it is an ammonite of some sort. There seems to be some structure in the photo and jellyfish fossils seem to be more shadows than substance. I took a photo of one I have in my 'old' display jar. Seems similar.

[kauffy]

I'm in the nautaloid/ammo/ gastro boat. I'm sure someone will chime in with more suggestions but general morphology suggests a coiled beasty. Its a bit worn so a definitive id may not be possible.

Possibly a jellyfish.

http://www.google.com/images?q=jelly+fish+fossil&btnG=Search&hl=en&gbv=1

http://ancientshore.com/2010/12/05/recognizing-fossil-jellyfish/

Tmaier I suggest when looking at something new the simplest, more common possibility is often the correct one whilst I see the shape of a jelly, newdog stated he found this in association with trilobites, leading me to believe the sediments are preserving hard parts. Not to say soft bodied organisms haven't been found in association with hard skeletal material, it is just that these sites are very uncommon not to mention the occurrence of jellyfish fossils in general is quite rare. When looking at something new, deductive reasoning must be used to work from the simplest possibility to the more complex ideas (ie ruling out the more common probabilities before suggesting more involved theories). I suggest Occam's Razor Principle http://math.ucr.edu/home/baez/physics/General/occam.html .

Regards, Chris

[BobWill]

No ammonites from any but the very latest Paleozoic. Not even any Ammonoids from before the Lower Devonian.

Also I don't see definite evidence of coiling, though some may emerge from cleaning. However, there is some similarity to the next to last image on the second row of tmaier's first link. Only jellyfish resting places are common fossils, not any soft parts.

Don't understand what's complex about suggesting jellyfish rest.

Edited August 18, 2014 by BobWill

[Ludwigia]

The image is straight on from above, but nevertheless I believe I can discern some coiling, which makes me think gastropod. It is round anyway.

[kauffy]

Only jellyfish resting places are common fossils, not any soft parts.

Don't understand what's complex about suggesting jellyfish rest.

I guess to me it just seems less likely than something hard, it looks vaguely "crushed" to a certain extent too which makes me think shell/exoskeleton rather than a preserved jelly rest. I never said it was too complex to suggest jellyfish, just that there are other more likely possibilities that need to be ruled out I'm not familiar enough with Silurian faunal assemblages to make that call, other than give my 2c based on what I see...

Cheers

[tmaier]

Some people see three dimensions and some see two. I see a flat stain.

Could we get an orthogonal view to see if there is anything beyond a stain? Play with the angle of the light to see if you pop a third dimension out of it.

[RyanNREMTP]

I'm going with the oral view of echinoid.

[fossilized6s]

If it's Silurian, i would venture a guess at coiled Cephalopod.

[FossilDAWG]

I'm going to go with: I need more photos, including some much more close up and showing any "texture" (if there is any). As it is, I see a circular(ish) object with something in the middle, with a vague and possibly misleading suggestion of coiling. Possibilities that come to mind include:

planispiral gastropod

coiled nautiloid

orthoconic nautiloid in cross section (siphuncle in middle)

recepticulitid

sponge

jellyfish impact crater

something else entirely

Don

[Herb]

my guess is a cross section looking down from the top,of a gastropod internal cast.

[Ludwigia]

I guess we'll all be just guessing until newdog supplies us with some more informative photos.

[tmaier]

I'm in the nautaloid/ammo/ gastro boat. I'm sure someone will chime in with more suggestions but general morphology suggests a coiled beasty. Its a bit worn so a definitive id may not be possible.

Tmaier I suggest when looking at something new the simplest, more common possibility is often the correct one whilst I see the shape of a jelly, newdog stated he found this in association with trilobites, leading me to believe the sediments are preserving hard parts. Not to say soft bodied organisms haven't been found in association with hard skeletal material, it is just that these sites are very uncommon not to mention the occurrence of jellyfish fossils in general is quite rare. When looking at something new, deductive reasoning must be used to work from the simplest possibility to the more complex ideas (ie ruling out the more common probabilities before suggesting more involved theories). I suggest Occam's Razor Principle http://math.ucr.edu/home/baez/physics/General/occam.html .

Regards, Chris

What you are proposing is not called deductive reasoning, it is called "shoehorning". Shoehorning is when you make the assumption that it SHOULD be a certain thing, and then try to force fit the data into making it become true. It's a common source of misidentification.

I realize jellyfish are very uncommon. There are few areas in the world that have yielded jellyfish. The Burgess shale, about 100 miles away, are one of those few places.

You shouldn't exclude something just because it is rare. You have to follow the data, no matter where it leads you. Otherwise you end up classifying everything as the same thing.

In this case, we need more data. The image is vague.

[kauffy]

Shoehorning, definitely not. I never said it cannot be a jelly, nor did I assume it should be anything and "force fit" any ideas. I'm sorry if anything I wrote led you to think that. All I suggest is working from the bottom to the top, to look at the common possibilities, if they don't fit search for other ideas based on the fossils characteristics. As you said the photo is vague, more angles are needed. All ideas are great when it comes to identifying an unknown.

[tmaier]

It's true that most of what people find are the common things that have already been found in that formation, so familiarity with the formation allows a person to see a small and distorted piece of a fossil and tell what it is likely to be.

But, when you approach a problem it is best not to have preconcieved ideas, that is bias, and leads to shoehorning. It is why so many drawers of fossils are "rediscovered" to be something else. They were shoved into the drawer with a shoehorn.

By the way, Ockham never discovered anything significant. It is likely his razor was the reason.

Always let the data speak for itself, and when you don't know what it is saying, put a ? next to it. - Maier's axiom

[Auspex]

Maybe more to think about:

Or maybe not...

It is very ambiguous.

It may be that the former life form is the small, better defined shape in the center, and the rest is a product of diagenesis.

[tmaier]

Notice that there is a scattering of jet black objects only in the zone of the "stain" and nowhere else in the rock. That is saying something, but I don't know what.

This is going to bug me till we get more photos...

[Stocksdale]

My first reaction was eroded gastropod. Probably just because I've found quite a few in my chunk of the Silurian.

[kauffy]

It's true that most of what people find are the common things that have already been found in that formation, so familiarity with the formation allows a person to see a small and distorted piece of a fossil and tell what it is likely to be.

But, when you approach a problem it is best not to have preconcieved ideas, that is bias, and leads to shoehorning. It is why so many drawers of fossils are "rediscovered" to be something else. They were shoved into the drawer with a shoehorn.

By the way, Ockham never discovered anything significant. It is likely his razor was the reason.

Always let the data speak for itself, and when you don't know what it is saying, put a ? next to it. - Maier's axiom

I don't disagree with anything you've said. Preconceived ideas can definitely lead to things being ignored...

However, once more i repeat myself, work from the bottom to the top.

I see (on Auspex's image) on the mid left of the specimen a fractured margin which appears to overlap a lower section (evidence of coiling?). The middle circular section clearly shows some sort of circular/spiral/concentric pattern which becomes smaller toward the centre. There are clear radial fractures, as well as an apparent fracture on the inside whorl top right of the middle circle, along with the initial fracture margin i mentioned earlier. This suggests a coiled animal to me with a hard crushable shell.

I'd be interested to hear your reasoning for jelly?

Edited August 19, 2014 by kauffy

[tmaier]

I see a big black stain with a darker core and a white squiggly thing. And it's out of focus.

Some people seem to see three dimensions and a spiral to this, and I can't see it. It a "Rorschach Rock", similar to the star ball thing we had last week.

[kauffy]

If its a cross section/ worn or flattened it doesn't necessarily need to be 3d to be a hard bodied animal

[Auspex]

When the evidence is this enigmatic, one man's shoehorn is another man's canning funnel.

"It could be..." a lot of things, and except for parsing the probabilities, there is little more we can do with the image presented. "Can't rule out..." is such an unsatisfying non-answer that no one wants to embrace it.

[fossilized6s]

Here's a different perspective to the photo.

I see a perfect circle in the middle instead of a coil now.....hmmm

[BobWill]

So far Chris has not posted additional pictures so let's use what we can point to in the only image we have and at least establish what we can agree on.

I'll start. For one thing, we don't have solid agreement on whether there is coiling or not. If there were there should be at least 2 things we would expect to see.

1. An overlap where one whorl encounters the next.

2. A gradual change in the diameter from one end of the whorl to the other.

There are a couple of places where there is an interruption in the otherwise smooth surface. The one on the right (of the original photo) is surely a crack. The less uniform one on the left does not extend all of the way across. The line is very irregular and stops right before the outer edge. An overlapping whorl would surely be more defined.

What appear to be changes in the width of the "whorl" could easily be due to matrix covering part of the fossil. Judging only by what is uncovered, instead of the gradual narrowing, the width is greatest on the upper left and the lower right, and the narrowest on the upper right and the lower left.

Of course the only way to establish this with the certainty some have already is more photos and maybe some matrix removal. I hope we get both but meanwhile could someone who's sure it's a coil please point out what I'm seeing wrong.