Reticulated, perforated rod with corals, Mississippian, UK

[TqB]

Does anyone recognise this?

I noticed it when scanning photos of a recently cut and polished piece of Frosterley "Marble" from Weardale, Co. Durham, UK. (upper Mississippian, Pendleian).

 

It shows in section as a rod about 5mm long, with perforations, central ridge and a fine reticulate pattern. My first thought was a Fenestella fragment but it doesn't look regular enough and I can find no mention of the reticulate structure. Also, I've never seen bryozoans in this part of the limestone though they occur at other levels.

 

Now I'm wondering about a dasycladacean alga - some look vaguely similar but all the Carboniferous ones I can find references to look simpler and fuzzier.  

 

Scale bar is 1cm,  divisions are 1mm

 

Contrast enhanced

 

 

In context, showing ghostly appearance amongst the corals

 

[Rockwood]

1 hour ago, TqB said:

My first thought was a Fenestella fragment

Mine as well. I don't think the holes would be in the corners as this appears to show though.

[Shamalama]

Kind of looks like the pustulose growth of a Cystiphylloides type coral, but the small cross section is troublesome.  I would still vote Coral though.

[Tidgy's Dad]

Coral fragment for me too. 

Nice piece of 'marble' by the way. very pretty.

[Rockwood]

This area does kind of show the right texture and preservation about where the edge of septa would be.

[TqB]

5 hours ago, Shamalama said:

Kind of looks like the pustulose growth of a Cystiphylloides type coral, but the small cross section is troublesome.  I would still vote Coral though.

 

2 hours ago, Tidgy's Dad said:

Coral fragment for me too. 

Nice piece of 'marble' by the way. very pretty.

 

1 hour ago, Rockwood said:

This area does kind of show the right texture and preservation about where the edge of septa would be.

 

Many thanks for looking, and for your suggestions. I've tried really hard to see it as a coral fragment but it doesn't fit any structures I'm familiar with - I've looked at a lot of material from this bed and this really stands out to me as a different, discrete element. I think the reticulations are an original structure but, even if they aren't, there are still the odd semi-regular holes. Here's a comparison with the area Rockwood pointed out and there is a similarity though it seems less organised:

 

What I had in mind with dasycladacean alga was something like this (actually Triassic specimens). The scale is right though I'm certainly not convinced by this either.

I'l try to find more specimens - there's a lot of this stuff I can do more slices of.

 

[Tidgy's Dad]

Good luck and keep us informed of any progress. 

Certainly a very interesting piece.

[daves64]

I wouldn't mind getting my hands on a slice of that marble "cake"... 

[TqB]

1 hour ago, Tidgy's Dad said:

Good luck and keep us informed of any progress. 

Certainly a very interesting piece.

Thanks Adam, I'll get grinding! The corals in the block this was from are somewhat atypical too - 6 species, with the usual Dibunophyllum almost absent - see photo below.

 

1 hour ago, daves64 said:

I wouldn't mind getting my hands on a slice of that marble "cake"... 

It's tasty stuff! Look up "Frosterley Marble" for more.

 

Here's the whole piece, and another from the same block, photographed submerged with a thin covering of water. (The large ones are Koninckophyllum, not the more common Dibunophyllum.) I'll put it in my Carboniferous corals thread soon.

 

 

 

 

[polyfenestella]

Hi Tarquin, just thought I’d better start looking at this forum ! The specimen in question is the cystoporate bryozoan Fistulipora incrustans as per the top left hand of this photo. The larger round autooecial apertures are separated by box like vesicles. The colonies can take the form of thin overlapping  sheets encrusting corals, crinoids etc.. to large foliaceous colonies. 
 

speak soon, Adrian.

[Rockwood]

Anyone else get the feeling this newbie isn't really such a newb at all ?

[polyfenestella]

Hi, yes you are right. Registered here circa three years ago and then went for a walkabout. Will dip in and out to offer any scraps of knowledge I have.