Tokio Formation

The Tokio Formation is a Late Cretaceous geologic formation in Arkansas and Oklahoma.^[1] Named in 1919 by Hugh Dinsmore Miser and Albert Homer Purdue in their study of Arkansas.^[2] 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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Tokio Formation
Stratigraphic range: Cretaceous
Type	Formation
Unit of	none
Sub-units	none
Underlies	Brownstown Marl
Overlies	Woodbine Formation
Thickness	up to 300 feet[1]
Location
Region	Arkansas, Oklahoma
Country	United States
Type section
Named for	Tokio, Hempstead County, Arkansas
Named by	Hugh Dinsmore Miser and Albert Homer Purdue[2]