All of the fossilized animals of the Burgess Shale were sea creatures living near an enormous carbonate reef that later was thrust upward by plate tectonic activity to form what is now called the Cathedral Escarpment. Long after the sea creatures of the Burgess Shale were entombed, these tectonic forces drove the fossils upward from the seafloor carrying them many miles eastward along faults, at the same time building the mountains that Walcott would climb millions of years later.
