Triarthrus beckii scale in cms CLASS - Trilobita ORDER - Ptychopariida FAMILY - Olenidae GENUS/SPECIES - Triarthrus beckii ROCK UNIT - Utica Shale (lower portion) AGE - Late Ordovician (450 million years old) LOCALITY - Hallsville, New York, USA Much of what we know about trilobites came from study of specially preserved Triarthrus fossils from central New York. Paleontologists unearthed complete specimens of Triarthrus eatoni from a single 3 cm thick siltstone bed north of Rome, New York. The special conditions under which the trilobites were buried allowed the mineral pyrite (iron sulfide) to preserve the legs, gills, antennae and stomachs before they decayed. When you see a trilobite like this one, remember that parts of the living animal are not usually preserved. An issue of Paleontographica Americana is devoted to these spectacular specimens, and is available from PRI. Ask for PA volume 8, number 53, Triarthrus eatoni (Trilobita): Anatomy of its exoskeletal, skeletomuscular, and digestive systems. PRI 41526