Cathedral Formation

Cathedral Formation is a Middle Cambrian carbonate rock unit in the southern Canadian Rockies of Alberta and British Columbia, named for Cathedral Mountain by Charles Doolittle Walcott. Deposited in shallow water on a broad algal reef or carbonate platform along the western edge of the North American craton, it began as limestone and was later altered to dolomite in many places. Its fossils, including stromatolites, oncolites, algal remains, and trilobites, help define its age and relation to nearby units. Its most important feature, the Cathedral escarpment, was crucial to the Burgess Shale’s exceptional preservation, and the formation has also supported mining of magnesite and other metals.

British Columbia · Canada