Here is a colonial coral from the Upper Ordovician time period. It was found in eastern Jefferson County, Kentucky. It is probably 14 cm in diameter. It is probably some sort of Foerstephyllum from the extinct Tabulata coral group.
There is a relatively new book entitled A Sea Without Fish - Life in the Ordovician Sea of the Cincinnati Region by David L. Meyer and Richard Arnold Davis with a chapter by Steven M. Holland. This type of coral is shown pages 76-78. They have a picture of an octagonal tool house built sometime in the early 1900s that is composed of colonial corals from the Richmondian coral beds in Madison, Indiana. The structure can be found in John Paul Park in Madison, Indiana.
They also cite the work of Ruth Browne on these types of coral. Ruth was a Louisville geologist who did some research back in the 1960s and 1970s in this area.