Hartshorne Formation

{{Short description|Geologic formation in Arkansas and Oklahoma, US}}

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| name = Hartshorne Formation

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| type = Formation

| age = Carboniferous

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| namedby = J.A. Taff{{cite journal|last1=Taff|first1=J.A.|title=Geology of the McAlester-Lehigh coal field, Indian Territory|journal=Nineteenth Annual Report of the United States Geological Survey, Part 3, Economic Geology|date=1899|pages=436–437}}

| region = Arkansas, Oklahoma

| country = United States

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| underlies = McAlester Formation

| overlies = Atoka Formation

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}}{{More citations needed|date=January 2024}}

The Hartshorne Formation is a geologic formation in Arkansas and Oklahoma. It preserves fossils dating back to the Carboniferous period.