| Here is a head shield, also called a cephalon, from the trilobite Olenellus clarki, collected from the Lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, Inyo County, California. |
| Here is a head shield, also called a cephalon, from the trilobite Olenellus clarki, collected from the Lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, Inyo County, California. |