A nummulite is a large lenticular fossil, characterized by its numerous coils,[1] subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan Nummulites, a type of foraminiferan. Nummulites commonly vary in diameter from 1.3 cm (0.5 inches) to 5 cm (2 inches)[2] and are common in Eocene to Miocene marine rocks, particularly around southwest Asia and the Mediterranean (e.g. Eocene limestones from Egypt). Fossils up to six inches wide are found in the Middle Eocene rocks of Turkey.[3] They are valuable as index fossils.

Temporal range: Late Cretaceous to Recent
Fossil nummulitid foraminiferans showing microspheric and megalospheric individuals; Eocene of the United Arab Emirates; scale in mm.
Scientific classification

Lamarck, 1801


The ancient Egyptians used nummulite shells as coins and the pyramids were constructed using limestone that contained nummulites.[4][5] It is not surprising then that the name "Nummulites" is a diminutive form of the Latin nummulus meaning "little coin", a reference to their shape.[6]

In 1913, naturalist Randolph Kirkpatrick published a book, The Nummulosphere: an account of the Organic Origin of so-called Igneous Rocks and Abyssal Red Clays, proposing the unconventional theory that all rocks had been produced through the accumulation of forams such as Nummulites.



  1. ^ 'Nummulite', Tiscali Dictionary of Animals, retrieved 17 August 2004
  2. ^ Isquirth, Irwin Richard (2011). In The World Book Encyclopedia. print.
  3. ^ 'Biggest Microbes', Guinness World Records 2001, p. 153.
  4. ^ Kaplan, Sarah, Brilliance without a brain Archived 2018-03-08 at the Wayback Machine, Speaking of Science, The Washington Post, March 7, 2018
  5. ^ Isquirth, Irwin Richard (2011). In The World Book Encyclopedia. print.
  6. ^ Hottinger, Lukas (2006-09-08). "Illustrated glossary of terms used in foraminiferal research". Paleopolis. Retrieved 2018-11-11.

Further readingEdit

  • Aigner, Thomas (January 1985). "Biofabrics as Dynamic Indicators in Nummulite Accumulations". Journal of Sedimentary Research. 55 (1): 131–134. doi:10.1306/212F8634-2B24-11D7-8648000102C1865D.
  • Kopaevich, L.F.; Lygina, E.A.; Nikishin, A.M.; Yakovishina, E.V. (2008). "The Crimean Eocene Nummulite Bank". Moscow University Geology Bulletin. 63 (3): 195–8. doi:10.3103/S0145875208030083. S2CID 129503182.
  • Racey, Andrew (2001). "A Review of Eocene Nummulite Accumulations: Structure, Formation and Reservoir Potential". Journal of Petroleum Geology. 24 (1): 79–100. Bibcode:2001JPetG..24...79R. doi:10.1111/j.1747-5457.2001.tb00662.x.
  • Papazzoni, Cesare Andrea (1995). "Nummulite biostratigraphy at the Middle/Upper Eocene boundary in the northern Mediterranean area". Rivista Italiana di Paleontologia e Stratigrafia. 101 (1): 63–80.
  • Guido, Adriano; Papazzoni, Cesare; Mastandrea, Adelaide; Morsilli, Michele; La Russa, Mauro F.; Tosti, Fabio; Russo, Franco (June 2011). "Automicrite in a 'nummulite bank' from the Monte Saraceno (Southern Italy): evidence for synsedimentary cementation". Sedimentology. 58 (4): 878–889. Bibcode:2011Sedim..58..878G. doi:10.1111/j.1365-3091.2010.01187.x.