One one of my regular trips up to Arkona, Canada I found this small scrap of fossil and hung onto to it as it reminded me of something. Well that something turns out to be a piece of a Bryozoan called Ptilopora striata (sometimes spelled Ptylipora). This bryozoan is typified by a single, strong, central "mast" with branches angling off at 45 degrees along the length. The individual branches sometimes have cross supports with neighboring branches as well. Overall the fossil has a herringbone like pattern. This is unlike similar fossils like Fenestella sp. or Polypora sp. who lack the central "mast". This specimen comes from the Hungry Hollow member of the Widder formation.
The reverse side of the fragment does not show any detail as it was overgrown by a colony of another bryozoan called Leioclema sp. I'm not sure what the fragmentary remains on top of the Leioclema are.
I wrote about another example of this rare bryozoan that I found in the Mahantango fm. and originally misidentified as the hydrozoan Plumalina plumaria.