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Annona Chalk

geologic formation, Arkansas

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionNov 8, 2025
Entity authorityQ17512201 ↗
Source-derived summary

The Annona Chalk is a geologic formation in Arkansas, Texas, Louisiana, and Oklahoma. It preserves fossils dating back to the Cretaceous period. The formation is a hard, thick-bedded to massive, slightly fossiliferous chalk. It weathers white, but is blue-gray when freshly exposed. The unit is commercially mined for cement. Fossils in the Annona Chalk include coelenterates, echinoderms, annelids, bivalves, gastropods, cephalopods, and some vertebrate traces. The beds range in thickness, up to over 100 feet in depth in some areas (such as at White Cliffs)., but thins to the east and is only a few feet thick north of Columbus, Arkansas and is completely missing to the east. The break between the Annona Formation and the Ozan Formation appears to be sharp with a few tubular borings up to a foot long extending down from the Annona in to the Ozan.

Exposures

Paleofauna

Ammonites

Baculites

B. crickmayi

B. taylorensis

Didymoceras

Didymoceratoides

D. binodosum

D. clardyi

Nostoceras

N. (Nostoceras) danei

N. (Nostoceras) monotuberculatum

N. (Nostoceras) plerucostatum

N. (Nostoceras) pulcher

Oxybeloceras

O. crassum

Pachydiscus

Placenticeras

Ostracods

See also

List of fossiliferous stratigraphic units in Arkansas

Paleontology in Arkansas

References

Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database".

Editorial summary

The public source identifies “Annona Chalk” as geologic formation, Arkansas. This brief keeps that definition visible, then builds a research path around Annona, Chalk and geologic.

Editorial reviewA dependable orientation record for establishing vocabulary, names and a first evidence trail. The current 199-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Annona, Chalk and geologic providing the first useful test.
Editorial analysis

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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Nov 8, 2025. The linked authority identifier is Q17512201. None of the 0 selected statements returned an explicit reference.

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Source & attribution

This entry incorporates text from “Annona Chalk” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.