Over 1,500 non-mineralized specimens, representing 50 distinct taxa that have a composition similar to earlier Burgess Shale type biotas, have been recovered from the formations in addition to a less abundant shelly fauna.[1] The make-up of the community varies significantly through the stratigraphic sequence, with both abundances and faunal composition changing as time progresses.[6] Small (1–3 mm wide) burrows are present in the sediment, but major burrowing is absent; this may suggest a paucity of oxygen in the water or sediment.[6] Particularly notable is the presence of bryozoa and graptolites,[6] forms that are absent in the Cambrian period.