Most biostratigraphic schemes for conodonts (and other fossils) are based on a combination of geographically separated stratigraphic sequences that contain abundant fossils. In developing biostratigraphy, generally little attention is given to identification of lithofacies that yield the fossils. Many sections in western North America include a mixture of sediments that represent a variety of marine environments. Such a stratigraphic mix of environment types yields a vertical sequence of fossils that represent a range of environments. Geographically separated but chronologically similar sections containing different environmental sequences may produce different sequences of fossils within a similar stratigraphic framework. Because of this, biostratigraphic...