Five marine biofacies based on conodont distributions are recognized for the Permian Phosphoria Formation and related rocks. They are: (1) facies with no conodonts, (2) facies with Hindeodus only, (3) facies with Hindeodus and (or) Neostreptognathodus and (or) Stepanovites and (or) Merrillina, (4) a transitional facies containing any of the components of biofacies 3 with either Neogondolella or Xaniognathus, (5) facies dominated by Neogondolella and Xaniognathus. These biofacies (1–5) represent progressive shore or nearshore to offshore differentiation of the conodont faunas.

Intervals of phosphate deposition within the Phosphoria Formation correspond to shoreward encroachment of offshore biofacies during trasgressive events. Elements...