Sub Class Trilobita
An uncalssified Trilobite from Marissa Mine. most of the cephalon is missing, making identification very hard. However it is very similar to the Griffithides pictured below.
scale in cms
|CLASS - Trilobita
ORDER - Ptychopariida
FAMILY - Phillipsiidae
GENUS/SPECIES - Griffithides sp.
ROCK UNIT - Crawfordsville Formation
Only a handful of trilobite families survived the large extinction event that occurred during the Late Devonian Period (about 365 million years ago) and only the family Phillipsiidae continued to the end of the Paleozoic Era (about 240 million years ago).