Unusual Pyritized Acorn Worm Fossil

Description: With only about a half dozen localities known, trilobites with soft tissue preservation are rare. A well-known site in the United States is Beecher’s Trilobite bed where examples of Triarthrus, Cryptolithus, and Cornuproetus are known. In 2005 a new location in Lewis County was discovered which will take its place in this select group as a site containing Triarthrus eatoni with preserved appendages. These trilobites were buried rapidly, resulting in an anxonic environment which allowed for infilling with fine-grained pyritic deposits that preserved the details seen here. The rich gold color is a striking contrast to the deep black matrix, making for a dramatic specimen available in very limited quantities. This fine example is another resident of the quarry known as an acorn worm. Acorn worms are hemichordates that are closely related to echinoderms. This one looks for all the world like a 400 million year old watch spring carelessly discarded in the quarry. They are new to science and as yet not described.