Triarthrus are plain looking trilobites that lived on the ocean floor in deep water and anoxic (low oxygen) conditions. Because of the low oxygen and deep water environment, the diversity of life in this shale is low. Other life includes deep water graptolites, some cephalopods, and a few gastropods.
The Utica shale is a dark grey shale found along many creek beds throughout central New York. The part of the Utica shale we collected in is called the Dolgeville Formation. This shale splits into thin layers. Some layers contain preserved fossils. Often the fossils are graptolites and heads of Triarthus trilobites that have accumulated by the slow deepwater currents. Sometimes a whole Triarthrus can be found. This was our goal, to find complete Triarthrus trilobites. Usually a person can find about one Triathrus trilobite within a few hours or more of searching.