Appekunny Formation

48°50′11″N 113°39′14″W[1]

Horodyskia moniliformis Is one of the oldest forms of multicellar metaozoan life known

Appekunny Formation is a thick series of rock strata located in the Lewis Range within Glacier National Park, in the U.S. state of Montana. The formation is primarily mudstone and siltstone deposited in a shallow sea during the Proterozoic. Not far from the eastern entrance to the Going-to-the-Sun Road at St. Mary, Montana, the formation can be easily seen on the slopes of Singleshot Mountain.[2] The Appekunny Formation contains bedding structures which may include the remains of the oldest metazoan (animal) on Earth known by the species name Horodyskia moniliformis.[3]

The sedimentary layers of the Appekunny Formation as seen on Singleshot Mountain

The Appekunny Formation is named after Apikuni Mountain and averages 1,970 feet (600 m) thick. The rock strata have been dated at between 1.2–1.4 billion years old.

References
  1. "Apikuni Mountain". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved May 27, 2018.
  2. Dyson, James. "The Belt Formations". The Geologic Story of Glacier National Park. National Park Service. Retrieved May 27, 2018.
  3. Fedonkin, Mikhail A.; Yochelson, Ellis L. (2002). "Middle Proterozoic (1.5 Ga) Horodyskia moniliformis Yochelson and Fedonkin, the Oldest Known Tissue-Grade Colonial Eucaryote". Smithsonian Contributions to Paleobiology (94): 1–29. doi:10.5479/si.00810266.94.1.

Further reading
  • Raup, Omar; Robert L. Earhart; James W. Whipple; Paul E. Carrara (1983). Geology Along Going-to-the-Sun Road, Glacier National Park, Montana. West Glacier, Montana: Glacier Natural History Association. ISBN 0-934318-11-5.
  • Price, Mike (January–March 2006). "Virtual Geomorphology" (PDF). Archived (PDF) from the original on 15 May 2006. Retrieved 2006-04-29.


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