Ammonites are an extinct group of sea animals that are related to today’s squid and octopus. These animals were incredibly common and were present as early as the Devonian period (419 to 358 million years ago). The last ammonites died out during the Cretaceous-Paleogene extinction event. Thanks to their ubiquity, scientists are often able to date a rock layer based on the type of ammonite present. 

This fossilized ammonite was found in McCurtain County, which was once underwater and part of what is now the Gulf of Mexico.