The following pictures are of a Devonian horn coral called Siphonophrentis elongata first described by C.S. Rafinesque and J.D. Clifford in the 1820 article, Prodrome d' une monographie des Turbinolies fossils du Kentucky (dans l' Amerique Septentrionale) found in Annales Gen. Science, Physics Vol. 5, pages 231-235. It was referred to by them as Turbinolia buceros var. elongata.
This one was found in the Jeffersonville Limestone in Louisville, Kentucky.