Sam Noble Museum
Trilobites are extinct arthropods that lived in the oceans and disappeared about 250 million years ago. This specimen was discovered in the Ordovician rocks of the Criner Hills of southern Oklahoma and is about 455 million years old. Complete skeletons of trilobites are rare because they would normally fall apart quickly after death, making it highly unusual to find hundreds of skeletons clustered together. A storm close to shore may have stirred up the sea floor and carried mud-laden waters offshore. As the storm waned, the mud was dumped on the sea bottom, burying the trilobites.