This trilobite is a member of the Order Lichida, Family Lichidae from the Silurian Rochester Formation deposits near Rochester, New York, known as Arctinurus boltoni. The species is referred to by some as the "Emperor of North American trilobites", and fittingly so. Notice the fine details in the many pustules found upon the surface of the exoskeleton, a characteristic often found in Lichid trilobites. The diagnostic pleural and pygidial spines are well in evidence, and the trilobite is quite 3-D in relief.