Late Ordovician and Early Silurian strophomenid brachiopods of Anticosti Island, Québec, Canada /

by Dewing, Keith
Calgary, Alberta : St. John's, Newfoundland : Canadian Society of Petroleum Geologists ; Geological Association of Canada, 1999

Ordovician and Silurian graptolite succession in the Trail Creek area, central Idaho -- a graptolite zone reference section /

by Carter, Claire
Washington : U.S. Govt. Print. Off, 1977