Ichnology is the branch of geology

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 that deals with traces of organismal behavior, such as burrows and footprints. It is generally considered as a branch of paleontology

Paleontology

Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...

; however, only one division of ichnology, paleoichnology, deals with trace fossils, while neoichnology is the study of modern traces. Parallels can often be drawn between modern traces and trace fossils, helping scientists to decode the possible behavior and anatomy of the trace-making organisms even if no body fossils can be found. An ichnologist is a scientist whose area of study and research is ichnology.

Ichnologic studies are based on the discovery and analysis of biogenic structures: features caused by living organisms. Thus, burrows, trackway

Trackway

A trackway is an ancient route of travel for people or animals. In biology, a trackway can be a set of impressions in the soft earth, usually a set of footprints, left by an animal. A fossil trackway is the fossilized imprint of a trackway. Trackways have been found all over the world...

s, trails and borings are all examples of biogenic structures, but not casts or molds of dead shells or other bodily remains. To keep body and trace fossils nomenclatorially separate, ichnospecies are erected for trace fossils. Ichnotaxa are classified somewhat differently in zoological nomenclature than taxa based on body fossils (see trace fossil classification

Trace fossil classification

Trace fossils are classified in various ways for different purposes. Traces can be classified taxonomically , ethologically , and toponomically, that is, according to their relationship to the surrounding sedimentary layers...

 for more information).

Examples include:

• Late Cambrian
  Cambrian
  The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
  
   trace fossils from intertidal settings include Protichnites
  Protichnites
  Protichnites is a genus of trace fossil consisting of the imprints made by the walking activity of arthropods. It is likely that more than one type of arthropod was responsible for these tracks. Euthycarcinoids, aglaspidids and eurypterids are possible contributors. Protichnites consists of two...
  
  and Climactichnites
  Climactichnites
  Climactichnites is an enigmatic, late Cambrian fossil formed on or within sandy tidal flats around .It has been interpreted in many different ways in the past, but is now known to be a trace fossil of a slug-like organism, thought to have moved by crawling on near-shore or on-shore surfaces or...
  
  , amongst others
• Mesozoic
  Mesozoic
  The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
  
   dinosaur footprints including ichnogenera such as Grallator
  Grallator
  Grallator is an ichnogenus which covers a common type of small, three-toed print made by a variety of bipedal theropod dinosaurs. Grallator-type footprints have been found in formations dating from the late Triassic through to the early Cretaceous periods...
  
  , Atreipus
  Atreipus
  Atreipus is an ichnogenus of trace fossil attributed to theropod dinosaurs....
  
  and Anomoepus
  Anomoepus
  Anomoepus gracillimus is the name assigned to fossil footprints first reported from Early Jurassic beds of the Connecticut River Valley, Massachusetts, USA in 1802....
  
  
• Triassic
  Triassic
  The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
  
   to Recent termite mounds, which can encompass several square kilometers of sediment

External links

• Ichnos An International Journal for Plant and Animal Traces