Preservation of Soft‐bodied Animals in Precambrian Sandstones at Ediacara, South Australia

With only two exceptions, this soft‐bodied fauna can be grouped naturally into two categories, ‘non‐resistant’ and ‘resistant’. Non‐resistant animals (mostly medusoids) collapsed or decayed before diagenesis had set the enclosing sediment; fossils occur in convex relief on the depositional bases of sandstone laminae. Resistant animals (most annelids, pennatulids, and unique groups) supported the covering sediment until it had set; fossils occur in negative relief on the bases of sedimentary laminae. Where there was little clay between adjacent quartzitic laminae, counterpart moulds or counterpart casts are also found on tops of underlying laminae.