Order Phacopida, Suborder Calymenina,
Arnheim formation, Highland County, Ohio
large and pristine example of a common trilobite from the Ordovician
of Ohio, Flexicalymene retrorsa, a Calymenid trilobite (Order Phacopida;
coming from the Ordovician Richmond Formation strata of Mount Orab,
Ohio. Studies have shown that trilobites such as these can be transported
over considerable distances by slow moving water currents.