Walnut Formation

{{Short description|Geologic formation in Texas, United States}}

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| name = Walnut Formation

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| type = Formation

| age = Cretaceous

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| region = Texas, Oklahoma

| country = United States

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The Walnut Formation is a geologic formation from the Albian Stage stretching from central Texas to southern Oklahoma. It is part of the Fredericksburg Group. The formation preserves fossils dating back to the Cretaceous period, notably marine invertebrates Exogyra texana, Gryphaea marcoui, and Carseyella walnutensis.Schlagintweit, F. (2021). Time to say goodbye: taxonomic revision of Dictyoconus walnutensis (Carsey, 1926), the last Lower Cretaceous representative of the genus. Historical Biology, 33(11), 2977–2988. https://doi.org/10.1080/08912963.2020.1839065Peterson, P., Smith, L., Gailloreto, N., Hanger, R. A., & Anonymous. (2009). Paleoecology of the Middle Cretaceous Walnut Formation, Bell County, Texas. Abstracts with Programs - Geological Society of America, 41(4), 16-.Milton, W. B. (1928). The Walnut Formation of Central Texas (Publication or Document No.) [Master's thesis, University of Texas]. Texas Scholar Works.