Analysis of the distribution of conodonts in sample sets measured down discrete beds exposed in the depositionally steeply dipping marginal-slope facies of the Upper Devonian reef complex of the Canning Basin has been undertaken in order to test the Seddon and the Druce interpretations of conodont biofacies. Each of the 14 sample sets was taken at measured intervals down single beds. The maximum difference in elevation between top and bottom samples was 65 m, indicating the water depth of the bottom sample to have been in excess of 65 m. Analysis of conodont distribution in the 53 sample points of the 14 sample sets does not indicate any clear depth segregation of conodont species that would correspond to the biofacies recognized by Seddon and Druce.