Could anyone please identify this fossil (if it is one). It was found on a beach at Blackwaterfoot on the west coast of the Isle of Arran, Scotland. Thanks
I think it is a rugose coral; I couldn't say which one.
Some nice illustrations here - http://www.fossilmuseum.net/Tree_of_Life/PhylumCnidaria/Rugosa-Coral.htm
It is a single Rugose coral.
It looks to have been eroded away because the fossil was softer than the rock it is in or it has been in an environment that has dissolved the fossil.
I think it is very interesting and hard to picture, well done nice find.
I have a couple like it and will post an image tomorrow
As promised some images of corals similar to yours mostly found on the Holderness coast by myself.
One cut and polished to show the internal structure, a single matrix free specimen in my hand for size comparison and a nodule with the coral missing leaving a negative impression inside of the rock.
Once again nice find and keep posting.