This picture is of a
Halysites catenularia (Linnaeus, 1767) chain
coral fossil. It existed during the Silurian period. The fossil was
found in Lickershamm, Gotland, Sweden.
Fossil was on display at the Natural
History Museum Vienna (
Naturhistorisches Museum Wien) on August 2024.
A fossil like this can be found in the Louisville, Kentucky USA area as well. Here is one on display at a Paris museum.
https://louisvillefossils.blogspot.com/2022/11/halysites-catenularia-chain-coral-fossil.html
