Algal reef (Cathedral Escarpment) with approximately 200 m of syndepositional relief.
Epiphyton boundstones, submarine cemented.
Minor contributions from Renalcis, Girvanella and spongiostromata. 

Abstract ref. 1554:
The Cathedral lithosome was generated by the expansions and contractions of a middle carbonate facies belt, deposited at low latitudes on a young, north-facing, thermally subsiding continental margin. It is bounded above by a quasi-synchronous contact, and below by a strongly diachronous contact that youngs eastward to intercept the upper contact. The outboard limit was controlled by, and partly corresponds to, a platform-bounding, organosedimentary reef established above a subtle, linear uplift at the beginning of the Middle Cambrian. Growth of the lithosome took place in three pulses, each succeeding an episode of abrupt sea level rise. Each of these rises introduced new fauna onto the platform and is interpreted as eustatic. At the beginning of each abrupt rise, the carbonate complex was reduced to a narrow rim. As eustatic rise slowed, the carbonate rim complex began to expand into the sheltered inshore basin above the mud-grade inner detrital sediments (Mount Whyte Formation) of the drowning phase. The facies are peritidial over and near the rim and lime-mud-dominated subtidal inboard. Outward expansion of the complex was limited during the early history of the lithosome, and effectively nil during the late stages. Growth of the Cathedral lithosome was terminated by a pulse by a pulse of sea level rise more pronounced than those preceding. This drowned the carbonate complex and admitted open-sea energy to the inshore basin. Craton-derived inner detrital muds (Stephen Formation) were then spread from the inshore basin, across the former site of the carbonate rim and, for the first time since the beginning of Cathedral deposition, into the offshore basin. A series of lithofacies maps on a palinspastic base illustrates paradoxical aspects of lithostratigraphic nomenclature: in the case of a deeply tongued lithosome like the Cathedral, the name given to a depositional unit commonly depends on the lithofacies of overlying and underlying units.

