[chris (OP)]

Not clear from your photo, but do you have any of the central raised pips?

Yes, I think, with the eye of faith, at least one is vaguely discernible: look at the facet above 3 on the ruler in my image - there are markings there that correspond to the central regions in the Moroccan specimen.

[Colin2B]

Yes, I think, with the eye of faith, at least one is vaguely discernible: look at the facet above 3 on the ruler in my image - there are markings there that correspond to the central regions in the Moroccan specimen.

Yes, that’s what I was looking at. Are there any in the other indentations?
In the Moroccan specimen the light coloured lines are visible running down the broken side, indicating the structure goes right through the rock. Any sign of that on your specimen? Perhaps @Bass can help us understand what we are looking at, it appears to be a cluster of anemone corals where the silt has filled in the gaps, just not sure why the lines are there.

You might be interested in this, ammonite eggs in Kimmeridge clay. Although named after the bay, the clays are found in Cambridgeshire and contain a lot of sea creatures. If you look on the rhs of the photo you can see the other half of the impression and how silt fills the gaps.

I had been thinking along the lines of pipe rock, but with hindsight it is a piece of coral, as mentioned above.

I agree, in pipe rock the burrows tend to be well spaced like ragworm on the beach.

[Bass]

Trumped?  We shall overcomb!
Hard rock suggests limestone- I still vote for coral!

[Colin2B]

We shall overcomb!

 

Hard rock suggests limestone- I still vote for coral!

Yes, I was wondering if you know what we are looking at in the Moroccan coral. Are these originally hexagonal creatures or is this an artefact of the fossilisation process? I’m intrigued by the white boundaries.

@chris look at this pic
The central pips in some of your hollows (lower half) look very much like these structures, but I can’t see clearly from your photo. This is Jurassic coral.
https://www.therockgallery.co.uk/jurassic-coral-unpolished---tisbury-wiltshire-5465-p.asp

[Bored chemist]

Trumped?  We shall overcomb!
Hard rock suggests limestone- I still vote for coral!

What's your view on a drop of vinegar?
The acid test?

[chris (OP)]

indicating the structure goes right through the rock. Any sign of that on your specimen?

No, it doesn't go right through, it's a veneer on the surface. The underside is dense brown ?chert.