Trace fossils

thumb|Fossilized stromatolite in Strelley Pool [[chert, about 3.4 billion years old, from Pilbara Craton, Western Australia]] thumb|Modern stromatolites in Shark Bay, Western Australia|Shark Bay, Western Australia

thumb|Plesiosaur gastroliths from [[Tropic Shale]] A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In other species the rocks are ingested and pass through the digestive system and are frequently replaced. The grain size depends upon the size of the animal and the gastrolith's role in digestion. Other species use gastroliths as ballast. Particles ranging in size from sand to cobble have been documented. T

thumb|A large coprolite of a carnivorous dinosaur found in Harding County, South Dakota, US

geological records of biological activity

thumb|The ichnogenus Thalassinoides: [[burrow fossil produced by crustaceans from the Middle Jurassic, HaMakhtesh HaKatan, southern Israel]] An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. Ichnotaxon comes from the Ancient Greek (íchnos) meaning "track" and English , itself derived from Ancient Greek (táxis) meaning "ordering".

REDIRECT Trace fossil

thumb|Oncolites from the upper Burgsvik beds (Silurian), with shell fragments as nuclei. The large flower is 2 cm in diameter. thumb|Oncolites formed around the Middle Jurassic [[gastropod Bactroptyxis trachaea (Normandy, France).]] Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by the growth of one or more species of microorganisms, usually containing cyanobacteria. Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. The oncoids often form around a central nucleus, such

Treptichnus is a genus of trace fossils (with modern analogues) representing a three-dimensional burrow. These fossil traces are known from marine, brackish, and freshwater deposits from the Ediacaran (550 million years ago) to the Upper Oligocene (24 mya).

fossilised footprint

Paramoudras, paramoudra flints, pot stones or potstones are flint nodules found mainly in parts of north-west Europe: Norfolk (United Kingdom), Ireland, Denmark, Southern Basque Country (Spain) and Germany. In Norfolk they are known as pot stones and can be found on the beach below Beeston Bump just outside Beeston Regis. In Ireland they are known as paramoudras. The term paramoudras was first used by Buckland in 1817 and is a corruption of a Gaelic name, probably padhramoudras "ugly Paddies" or peura muireach "sea pears".

Cynosaurus is an extinct genus of cynodonts. Remains have been found from the Dicynodon Assemblage Zone in South Africa. Cynosaurus was first described by Richard Owen in 1876 as Cynosuchus suppostus. Cynosaurus has been found in the late Permian period. Cyno- is derived from the Greek word kyon for dog and –sauros in Greek meaning lizard.

thumb|Modern thrombolites in Lake Clifton, Western Australia|400x400px thumb|Jurassic thrombolite formed around a tree trunk; Purbeck Formation, [[Isle of Portland, Dorset, England.|400x400px]] thumb|Fossil Thrombolites at Lake Walyungup|400x400px Thrombolites (from Ancient Greek θρόμβος thrómbos meaning "clot" and λῐ́θος líthos meaning "stone") are clotted accretionary structures formed in shallow water by the trapping, binding, and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.

Radulichnus is an ichnogenus of trace fossil which resembles the marks produced by the action of a mollusc's radula on sediment. As an ichnogenus, its classification is based solely on appearance, and does not necessarily imply anything of the affinity of the organism which produced the trace. However, fossils of Kimberella have been found at or near the ends of Radulichnus traces, leading to the possibility that some traces were made by Kimberella.

Bromalites are the fossilized remains of material sourced from the digestive system of organisms. As such, they can be broadly considered to be trace fossils. The most well-known types of bromalites are fossilized faeces or coprolites. However, other types are recognised, including: regurgitalites (fossilized remains of vomit or other regurgitated objects such as owl pellets); cololites (intestinal contents); and gastrolites (stomach contents). Regurgitalites and coprolites are thus essentially known only after they have left the body of the producing organisms, whereas gastrolites and cololit

The Poozeum is a museum in Williams, Arizona, United States, dedicated to coprolites (fossilized feces). It was founded in 2014 as a website and resource center by George Frandsen, who owns the world's largest collection of coprolites. Pieces from Frandsen's collection served as a traveling exhibition before the Poozeum opened its physical location in 2024.

stratigraphic layer in Antarctica

Helminthopsis is an ichnogenus of trace fossil that is found preserved on the bedding planes of fine-grained sedimentary rocks. It is characterized by short, curvilinear, nonbranching, parallel-sided, unlined traces on bedding surfaces. It is thought to represent the submarine feeding trails of an invertebrate organism that worked the surface of muddy substrates in search of food. Because Helminthopsis traces never cross over themselves, the ichnogenus is distinguished from similar traces assigned to the Gordia ichnogenus. The similar sounding, but now obsolete, ichnogenus Helminthoida refers