Fossil id please :)

Mountainsandh

I found a fossil in co Clare, I was trying to find out what it was online, but there's nothing very obvious to me, other than I'm guessing it's some sort of sea life, like these tubes where there's a squid like creature living in ?

I'd love to read your opinions. There are other bits encrusted in the stone so there are other shots on my pix.ie album here.

Wibbs

I'd reckon it's a solitary rugose coral from the lower carboniferous. A skinny version of this:

Mountainsandh

Thanks Wibbs, it looks like it could be that alright.
By Googling carboniferous corals thanks to your suggestion, I also hit on crinoid stalks, that look very much like that too !

http://www.ephemerala.citymax.com/i//sm_crinoid1.JPG

http://www.geology4today.com/uploads/1/8/1/6/18166011/8527429_orig.jpg?1377489575

Wibbs

Not far off M, though crinoid stalks don't taper, or not to that degree.

royalflush2003

Is this a fossil of some sort ! Found on beach !

royalflush2003

Anyone ?

slowburner

royalflush2003 wrote: »

Is this a fossil of some sort ! Found on beach !

It is very difficult to say what this is from one photo. If you could post up a few photos showing the opposite side or back of the stone (complete, including the point, if there is one), as well as photos of the sides or profile, and something like a ruler or tape measure for scale, it would be a great help in making a decision as to whether this is a natural or man-made phenomenon.
It is probably natural. However, the fact that it appears to be so symmetrical warrants a more detailed examination.
It would also be useful to know where it was found.

Rubecula

I agree with slowburner, the stone doesn't at first sight look like a fossil bearing type and it could be a weathered man made carving. However more photos would help in identifying what it is. Any other details you can provide would also be a great help.

royalflush2003

Ok will do thanks - found on Greystones beach in wicklow -

Rubecula

OK this is not a definitive answer as frankly I don't really know the place, however I think it is a really well weathered piece of architectural stone possibly from a demolished building. Maybe a piece of internal decorative stone work. Have you tried asking in the archeology forum?

I may be wrong of course as I often am, however it looks less and less fossil like every time I view the photo.

slowburner

I have shown this curious stone to a number of experts and the general feeling is that it is natural. What interested me was the overall symmetry, along with the possibility that the symmetry was designed to embellish or highlight the annular inclusion.
That possibility cannot be ruled out, but it is not possible to rule it in either. The stone has been so water-rolled that it would not be possible to state with any degree of confidence that the stone has been worked.
If the annular area itself was carved, it would be expected that there would be some evidence of the surface being reduced to leave the ring proud of the surface.
To put it another way: the stone could have been carved or shaped but we will never know, because the tide has worn away any of the signs that archaeologists use to tell if or how a stone was shaped by the hand of man.

I am not entirely convinced by the opinions of the few experts I have contacted. As Rubecula said, there is no obvious difference in the fabric of the ring which would lead to differential erosion. However, there may have been something at that point which protected the area for a time and the remainder of the stone eroded away at a faster rate while it was in place, leaving the ring above the surface when the protective piece finally eroded away. This could also explain the shape of the feature which seems to be around the right size and shape for a shell fossil but it also depends on the main rock type being more easily eroded than the fossil.
So, perhaps this 'thinking out loud' will help to see the value of good quality photos, or even better, a first hand viewing. The staff of the National Museum of Ireland might have another opinion if they saw it first hand.

Wibbs

My humble FWIW is that it's a heavily weathered lower carboniferous marine gastropod, a sea snail, like this one.



The reason the fossil isn't a different colour to the rest of the stone is because what you're seeing is the original material and minerals that filled the empty space of the shell, but the shell itself has eroded away.

Here's a crappy pic of an earlier stage in the process.



Hopefully you can make out where the shell has worn away at the top, leaving a skirt of shell at the bottom and the internal cast exposed. Fast forward a few years in the surf and you'd get Royalflush's rock.

royalflush2003

Here is the underside of it ...thanks

Wibbs

Yea defo carboniferous limestone IMH.

slowburner

royalflush2003 wrote: »

Here is the underside of it ...thanks

Seeing this photo, I am confident that the stone is completely natural, and that the formation of the annular feature was ably explained by Professor Wibbs.

royalflush2003

Ok guys great , thanks most welcome info ðŸ‘