While I find quite a bit of Cladopora from deposits like the Centerfield mbr. of the Ludlowville Fm. or the Hungry Hollow mbr. of the Widder Fm., it was a little surprising for me to find some isolated fragments in the Windom Shale at Penn Dixie. While one does find corals in certain layers within the Windom shale, they are not as abundant as at other sites.
Looks like there is a small break on the "posterior" side that had some sediment fill in. It kind of looks like a mouth now!
I think these can be classified as Cladopora roemeri. The Windom Shale mbr. of the Moscow Fm. is Devonian (Givetian stage) in age.