Page:Walcott Cambrian Geology and Paleontology II.djvu/200



All of the specimens illustrated on this plate are from locality (35k) Middle Cambrian: dark siliceous shales in the Burgess shale member of the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, one mile (1.6 km.) northeast of Burgess Pass, above Field, British Columbia.