Dewey Formation

{{Short description|Geologic formation in Iowa and Oklahoma, United States.}}

{{Infobox rockunit

| name = Dewey Formation

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| type = Formation

| age = Carboniferous

| prilithology = Limestone

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| namedfor = Dewey, Washington County, Oklahoma

| namedby = D. W. Ohern, 1910{{cite journal |last1=Ohern |first1=D. W. |title=The stratigraphy of the older Pennsylvanian rocks of northeastern Oklahoma |journal=The State University of Oklahoma Research Bulletin |date=1 December 1910 |volume=4 |pages=30–37 |url=https://babel.hathitrust.org/cgi/pt?id=pst.000021685682;view=1up;seq=3 |access-date=2 August 2018}}

| region = Iowa, Oklahoma

| country = United States

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