Substrates affected by biogenic processes range in scale from individual particles of clay to massive seacliffs or submarine slopes, and they include conventional sediments, numerous organic substances, and all three classes of rocks. The tolerances, activities, and adaptations of organisms are equally complex and pervasive, as reflected by diverse components of bioerosion, biodeposition, biostratification, and bioturbation. Through most of the Phanerozoic column, therefore, organism-substrate interrelationships have been as significant for general sedimentary geology, geochemistry, and benthic paleoecology as for ichnology per se. Indeed, increasing interdisciplinary communication among geologists, ecologists, and chemists bodes well for the future. Even so, several shortcomings remain in our understanding of bioturbation and bioturbate textures, including our inability to conceive a quantitative genetic classification of these phenomena. Intensive bioturbation and its measurement, together with the effects of endobenthic tiering and early diagenetic chemical processes on the preservation of biogenic sedimentary structures, are the principal nascent fields for further interdisciplinary study.