Tokio Formation

{{Short description|Geologic formation in Arkansas & Oklahoma}}

{{Infobox rockunit

| name = Tokio Formation

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| type = Formation

| age = Cretaceous

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| namedfor = Tokio, Hempstead County, Arkansas

| namedby = Hugh Dinsmore Miser and Albert Homer Purdue{{cite journal|last1=Miser|first1=Hugh D.|last2=Purdue|first2=A.H.|title=Gravel deposits of the Caddo Gap and De Queen quadrangles, Arkansas|journal=U.S. Geological Survey Bulletin|date=1919|volume=690-B|pages=19–24}}

| region = Arkansas, Oklahoma

| country = United States

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| unitof = none

| subunits = none

| underlies = Brownstown Marl

| overlies = Woodbine Formation

| thickness = up to 300 feet{{cite journal|last1=McFarland|first1=John David|title=Stratigraphic summary of Arkansas|journal=Arkansas Geological Commission Information Circular|date=2004|orig-year=1998|volume=36|page=28|url=http://geology.ar.gov/pdf/IC-36_v.pdf}}

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The Tokio Formation is a Late Cretaceous geologic formation in Arkansas and Oklahoma. Named in 1919 by Hugh Dinsmore Miser and Albert Homer Purdue in their study of Arkansas. They assigned the town of Tokio, Hempstead County, Arkansas as the type locality, but did not designate a stratotype for this unit.

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