Phacops is a trilobite that lived from the Silurian to the Devonian Period. It had a large and bumpy glabella, or middle cheek.
Even though many other trilobites could roll up like pill bugs, Phacops could do it more efficiently than other trilobites. But sometimes when they were rolled up they could get buried in sediment. Many fossils of Phacops are found rolled up into balls.
Phacops was up to six inches long. Some people recognize it by its eyes, which resembled frog eyes.
Phacops has been found in the northeast United States and Morocco, and is the state fossil of Pennsylvania.
Phacops had a 360 degree view because it could turn its eyes to different angles. Phacops is one of the most common Devonian trilobites.