Extremely Rare Comptonaspis swallowi Mississippian Trilobite

This is a fine prone example of a member of the Order Proetida, Family Proetidae called Comptonaspis swallowi. Coming from the Kinderhookian Stage (359-348 m.y.a) deposits of Saline County, Missouri, this trilobite is a member of the last surviving order of trilobites, the Proetida. It is found in these same deposits with another rare trilobite, Breviphillipsia sampsoni, but is found at only 10% the frequency of that taxon. It is distinguished in part from that taxon by its smooth exoskeleton.