It was a moderately large trilobite (14 cm.) with a semicircular head, free cheeks each ending with a long, narrow, recurved spine, and relatively large eyes. Its elongated trunk was composed of 20 segments and again was adorned with longish, recurved lateral spines. Its pygidium (caudal shield) was comparatively small and had one or two pairs of long spines on the posterior margin. Paradoxides is a characteristic Middle Cambrian trilobite of the 'Atlantic' (Avalonian) fauna. Avalonian rocks were originally deposited near a small continent in the Paleozoic Iapetus Ocean. Avalonian beds are found in a narrow strip along the East Coast of North America as well as in Europe.Developmental stages of this genus are also known.