“…I. gaspensis, are new. All three genera co-occur, for example, in the Pentagon Shale-Pagoda Limestone interval in northwestern Montana, U.S.A. (Deiss, 1939), and the presence of two of the genera in association has been noted from most well-known coeval middle Cambrian localities of Laurentian North America, such as Utah (Robison, 1964), Idaho (Resser, 1939), the Grand Canyon region (McKee and Resser, 1945), British Columbia (Rasetti, 1951), Pennsylvania (Rasetti, 1965), Georgia (Schwimmer, 1989), New York (Bird and Rasetti, 1968), and Alaska (Palmer, 1968).…”