One of the more unusual finds from Arkona is the plate below. It looks like a stromatolite or stromatoporid that was colonized by a pair of inarticulate brachiopods. Some inarticulate brachiopods attach their pedicle valve to a hard substrate which then grows along the surface while the rest of the body is covered by the brachial valve. The plate below has what appears to be two separate pedicle valves from some unknown inarticulate brachiopod.
It's not uncommon to find this type of fossil but usually the brachial valve is present and obscures the pedicle valve. This was found in the Hungry Hollow member of the Widder formation (Devonian period, Givetian stage)near Arkona, Ontario, Canada.