Elrathina cordillerae
Trilobite
Middle Cambrian
Burgess Shale, Stephens Formation
Field, British Columbia, Canada

18mm trilobite and 24mm sponge on 114mm slab.

Elrathina is a genus of trilobite best-known from the Burgess Shale.  It has also been reported from the Middle Cambrian of Utah and Montana.

This is an interesting piece for the collector looking for fossil associations.