I believe this fossil would be classified as a colonial coral or maybe a cluster of horn corals attached together. The Stumm book on
Devonian and Silurian Corals of the Falls of the Ohio (1964) identifies it as a
Billingsastraea ingens. The Falls of the Ohio State Park web site lists as a
Heliophyllum ingens (
LINK). It was found in the Middle Devonian Boyle Limestone of Nelson County, Kentucky. The fossil can be yours:
eBay LINK
