This trilobite is a member of the Order Phacopida, Family Dalmanitidae from the Silurian Clinton Group Rochester Formation deposits near Rochester, New York, known as Dalmanites limulurus. The species name is derived from perceived similarities in appearance to the modern-day horseshoe crab Limulus. Notice the fine details present, including the eye facets, something not often seen. There are numerous Brachiopod shells found on both the front and rear of the matrix, an indication of other denizens of the depths that shared the trilobite's realm.