Ogygopsis klotzi
The Burgess Shale Formation in the Canadian Rockies of
British Columbia is world-famous for its abundance of soft-bodied fossils. Mt.
Stephen is a classic fossil locality to the south of the best Burgess Shale
quarries. The rocks of Mt. Stephen are also Burgess Shale Formation, but
soft-bodied fossils are far less common. The most common fossils seen in
rocks on the slopes of Mt. Stephen are decent-sized specimens of Ogygopsis
klotzi trilobites. Disarticulated pygidia, cranidia, thoracic
segments, and partially- to fully-articulated specimens are common in these
rocks. The area is now a national park, but vintage specimens are
sometimes available for examination.
The fossil shown below is an Ogygopsis tail +
three thoracic segments. The larger slab of which this is a part has many
other fossils, including additional Ogygopsis material, other polymeroid
trilobites, orbiculoid brachiopods, and Selkirkia worm tubes.
Ogygopsis klotzi pygidium (tail) (2.1 cm across) in slightly
calcareous mudshale. From the “Ogygopsis beds” of the Burgess
Shale Formation on Mt. Stephen, British Columbia, southwestern Canada (vintage
specimen).
Photo by Nicole Byrd.