These large gastropods were ornamented with spines or tubercles, partly to reinforce their shells and partly to be able to hide in amongst the gravel right at the contact with the rough waters, where this association used to live. The organisms were then transported into deeper waters forming the deposits we now call 'Pachycardia Tuff'.

These spherical snails could grow to a considerable size and were able to remain stable on powerful waves thanks to their smooth surface. We can imagine these molluscs were brightly coloured, as a few specimens reveal traces of colour, even if we do not know yet which colour they were.