Pleurodictyum americanum coral from the Wanakah Shale

There is a bed present within the Wanakah shale member of the Ludlowville formation (Devonian, Givetian stage) called the "Pleurodictyum bed". As may be guessed, the coral Pleurodictyum americanum is common within the layers of this zone. Below are a couple of examples that I found along the shore line of Lake Erie. They stand out for me because of the substrate they colonized.

Specimen #1 is narrow because it started on the shell of a Paleozygopleura sp. gastropod.

Specimen #2 chose a section of Sulcoretipora sp. bryozoan.

Since Pleurodictyum needed a hard substrate to cement itself to, it's not surprising to find skeletons of other animals being used.