01_erwin_quartzite_skolithos_wall_16 Erwin Formation quartzite with trace fossil Skolithos arranged in parallel arrays. Skolithos linearis were most probably made by burrowing phoronids or polychaete annelids (e.g., marine bristle worms).
02_erwin_quartzite_skolithosi_18 Top of quartzite with Skolithos burrowing trace fossils.
