1.9" Fossil Rugose Coral (Goniophyllum) - Sweden

This is a 1.9" long example of the Siluran coral (Goniophyllum pyramidale) from Sweden. These rugose corals had four lids at the opening of the calyx that they could close for protection of their mouthparts. When closed, they created the shape of a pyramid, hence the species name, pyramidale.