Cordania & Kettneraspis Trilobites - Black Cat Mountain, Oklahoma
This is a unusual association of two types of trilobites from the Haragan Formation of Oklahoma. There is a .6" long Cordania falcata right next to a 1.15" long Kettneraspis williamsi. The Kettneraspis is partially exposed, but both trilobites have wonderful shell detail and good preparation.
The Black Cat Mountain Quarry produces a limited number of arguably the most beautiful trilobites in the United States each year. Each specimen is meticulously prepared by Bob Carroll under microscope to expose the smallest details. This is a very time consuming process taking many hours but yields spectacular results.
Trilobites were a very diverse group of extinct marine arthropods. They first appeared in the fossil record in the Early Cambrian (521 million years ago) and went extinct during the Permian mass extinction (250 million years ago). They were one of the most successful of the early animals on our planet with over 25k described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left a excellent fossil record.