The cone-in-cone structures form in sedimentary environment.The specimen pictured appears to be from the Coral Ridge Member of the New Provi...

Fossil appears to be a  Pleurodictyum maximum coral. It is credited to Gerard Troost in the 1840 5th Annual Report on the Geology of Tennes...

Images of what appears to be an  Arachnophyllum striatum coral fossil. It was found in the Louisville Limestone of Jefferson County, Kentuc...