Skolithos is a common trace fossil

Trace fossil

Trace fossils, also called ichnofossils , are geological records of biological activity. Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings , urolites , footprints and feeding marks, and root cavities...

 ichnogenus whose original form consisted of approximately vertical cylinders. One well-known occurrence of Cambrian trace fossils is the famous 'Pipe Rock' of northwest Scotland. The 'pipes' that give the rock its name are closely packed straight tubes, which in this case were presumably made by a worm-like organism. The name given to this type of tube or burrow is Skolithos, which may be 35 cm (14") in length and between 2 to 5 cm (0.8 to 1.6") in diameter. Such traces are known worldwide from sands and sandstones deposited in shallow water environments, from the Cambrian Period onwards. Some have a helical form. Skolithos is typically marine, but is also known from freshwater lacustrine settings. It is usually associated with high-energy environments close to the shoreline. Trypanites

Trypanites

Trypanites is a narrow, cylindrical, unbranched boring which is one of the most common trace fossils in hard substrates such as rocks, carbonate hardgrounds and shells . It appears first in the Lower Cambrian , was very prominent in the Ordovician Bioerosion Revolution , and is still commonly...

is a similar form but is excavated in hard substrates as a boring

Bioerosion

Bioerosion describes the erosion of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and fish; it can occur on coastlines, on coral reefs, and...

 trace fossil. Also related are Ophiomorpha

Ophiomorpha

Ophiomorpha is an ichnotaxon, usually interpreted as a burrow of an organism living in the near-shore environment. It is often considered part of the Skolithos ichnofacies....

and Diplocraterion

Diplocraterion

Diplocraterion is an ichnogenus describing vertical U-shaped burrows having a spreite between the two limbs of the U. The spreite of fainter U-shaped traces appears above and below the final tunnel, made as the organism moved up and down through the sediment.- Further reading :* Šimo V. &...

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