Trilobite Death Assemblage from Utah Marjum Formation

Description: Coming from the Cambrian Marjum Formation deposits of Millard County, Utah this is a fine association plaque with representatives of each of the three orders of trilobites that comprise most of those found in the Middle Cambrian of Utah. The trilobite farthest right is an example of the genus Modocia. The next trilobite is Bathyuriscus fimbriatus, seen here with the librigenae present. To the left is the agnostid, Onymagnostus seminula. The members of the Agnostida are mostly thought to have been planktonic in nature. Most are blind, and have a pygidium equal in size to the cephalon (ispopygous), making it hard to tell which end was which! This fine plaque makes an excellent display specimen of a death assemblage of finely-preserved Middle Cambrian trilobites of Utah.