The Chepultepec Formation, is an

Early Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. Th ...

-age

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

in the

Appalachia Appalachia () is a cultural region in the Eastern United States that stretches from the Southern Tier of New York State to northern Alabama and Georgia. While the Appalachian Mountains stretch from Belle Isle in Newfoundland and Labrador, ...

n regions of Eastern North America. Also known as the Chepultepec Dolomite, it is a unit of the Upper

Knox Group The Knox Group is a widespread geologic group in the Southeastern United States. Though not commonly fossiliferous, it preserves fossils dating back to the Cambrian period. Typical lithologies include thick-bedded cherty dolomites and limeston ...

, overlying the

Copper Ridge Dolomite The Copper Ridge Dolomite is a geologic formation in Alabama. It preserves fossils dating back to the Cambrian Period. See also * List of fossiliferous stratigraphic units in Alabama This article contains a list of fossil-bearing stratigraph ...

and underlying the

Longview Longview or Long view may refer to: Places Canada *Longview, Alberta, a village *Longview, British Columbia, a former cannery town *Longview Range, British Columbia; a mountain range United Kingdom England *Longview Psychiatric Unit, a hospital ...

Kingsport Kingsport is a city in Sullivan and Hawkins counties in the U.S. state of Tennessee. As of the 2020 census, its population was 55,442. Lying along the Holston River, Kingsport is commonly included in what is known as the Mountain Empire ...

Mascot A mascot is any human, animal, or object thought to bring luck, or anything used to represent a group with a common public identity, such as a school, professional sports team, society, military unit, or brand name. Mascots are also used as fic ...

sequence. The Chepultepec Formation is a primarily

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...

and dolomite formation, the earliest formation of the

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...

period in its area. Further north, it is equivalent to the Stonehenge Formation of the Beekmantown Group. The formation was first described from Allgood, Alabama, and has also been found in

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to ...

and

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography an ...

. Allgood was originally named "Chepultepec", providing its name to the formation as well. In Virginia, the Chepultepec Formation has a habit of forming large natural

arch An arch is a vertical curved structure that spans an elevated space and may or may not support the weight above it, or in case of a horizontal arch like an arch dam, the hydrostatic pressure against it. Arches may be synonymous with vau ...

es, including Natural Tunnel in Scott County and

Natural Bridge A natural arch, natural bridge, or (less commonly) rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion f ...

Rockbridge County Rockbridge County is a county in the Shenandoah Valley on the western edge of the Commonwealth of Virginia. As of the 2020 census, the population was 22,650. Its county seat is the city of Lexington. Rockbridge County completely surrounds the i ...

References

* Ordovician geology of Tennessee Ordovician geology of Virginia Ordovician southern paleotemperate deposits {{Virginia-geologic-formation-stub