This authentic trilobite fossil has been freed of its surrounding stone. It is likely a Calymenes and measures 3.6 inches long by 2.2 inches wide and 1 inche high.
Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record occurred about 521 million years ago, and they roamed the oceans for over 270 million years before beginning a drawn-out decline to extinction, when all trilobite orders disappeared about 252 million years ago. The trilobites were among the most successful of all early animals.