Ecostratigraphy’s Basis, using Silurian and Devonian Examples, with Consideration of the Biogeographic Complication

Ecostratigraphy enables one to use a combined community ecologic and biogeographic analysis to provide a far more detailed, evolutionarily based biostratigraphy. It makes clear the lower level correlation precision all too commonly present between biotas from different biogeographic and ecologic units. It capitalizes on the improved correlation precision made possible by combining data from adjoining, either intertonguing or mixed, ecologic and biogeographic units. It emphasizes the importance of careful taxonomic work on the phyletically evolving species within generic lineages, typically the uncommon to rare genera within any community group. It emphasizes the critical importance of working with large fossil collections that have a much better chance of recovering the uncommon to rare genera, the rarefaction phenomenon.