Here is a horn coral fossil called Streptelasma corniculum (Hall, 1847). It existed in the Ordovician Period (490-443 million years ago). The fossil was found in the Richmond, Kentucky USA.
The fossil was on display in the Evolving Planet section of The Field Museum of Natural History in Chicago Illinois, USA as of August 2020. Accession number is P9537.
Learn more about this fossil here:
https://www.ordovicianatlas.org/atlas/cnidaria/anthozoa/rugosa/streptelasmatidae/streptelasma/
