A large coral fossil fragment

This fossil was found in the north Alabama / Tennessee Valley area. It is about 1.5 in diameter and, compared to the ones intact, six to seven inches long with three others nearly touching.

I was looking into the possibility of it being a siphonophtentis gigantea but it is extremely unlikely to come by a fossil from the devonian period in that area. Most fossils I encounter are from the Mississippian period.