Stratigraphically significant Early and Middle Ordovician gastropod occurrences, western and northwestern Canada

Abstract

Several biostratigraphically important gastropod genera are described from Alberta, British Columbia, Yukon Territory, and the District of Mackenzie. Malayaspira is present in the mid-Ibexian Kechika Group. Palliseria, Maclurites, Teiichispira, Malayaspira, Barnesella, and Ceratopea occur in the Skoki Formation (highest Ibexian and lower Whiterockian) and Helicotoma and Palliseria in the Sunblood Formation (lower Whiterockian). The largest known Teiichispira operculum is illustrated. The forms are particularly useful for age determination within relatively narrow limits and most of the taxa are readily identified in the field.