I pestered my friend Christian to send me some Palaeocyclus fossils from Gotland and he came through in our last exchange. These are small little solitary rugose corals that lived during the Silurian and colonized the substrate. They are an important fossil genera for correlation of rocks found across Europe but they are not so common here in North America.
Here is a loose specimen
And one that is embedded in the matrix.
Both specimens come from the Visby limestone beds near Hallshuk on the island of Gotland, Sweden. The Visby limestone is dated to the Wenlock stage of the Siluran.