Ichnology is the study of animal-sediment relationships and encompasses the examination of both modern and ancient structures. Trace fossils are biologically produced structures that include tracks, trails, burrows, borings, fecal pellets, and other traces made by organisms. Owing to their nature, trace fossils can be considered as both paleontological and sedimentological entities, thereby bridging the gap between two of the main subdivisions in sedimentary geology.