Aulocystis coral from Arkona

Below are some pieces of Aulocystis from the Hungry Hollow member of the Widder formation (Devonian, Givetian) near Arkona. They are often found as loose pieces in the weathered rubble.

There are three species of Aulocystis listed in the Checklist for the Hungry Hollow member of the Widder formation: A. dichotoma (Grabau), A. intermedia (Nicholson) and A. "nobilis". Of the three, A. dichotoma seems to be the best fit based on this illustration from Grabau's classic "Geology and Paleontology of Eighteen Mile Creek".

Note that Aulocystis was once called Ceratopora.

Here are some clusters of Aulocystis auloporidea that I found in the Silica Shale.