Modocia typicalis Trilobite

Name: Modocia typicalis 

Trilobite Order Ptychopariida, Family Marjumiidae

Geologic Time: Cambrian 

Size: approx 3.75cm x 2.75cm

Matrix size: approx 9.5cm x 8.75cm

Fossil Site: Marjum Formation, House Range of Utah

A trilobite is any member of a group of extinct fossil arthropods easily recognized by their distinctive three-lobed, three-segmented form. Trilobites, exclusively marine animals, first appeared at the beginning of the Cambrian Period, about 542 million years ago, when they dominated the seas.