ORIGINAL HORIZONTALITY

"Strata either perpendicular to the horizon or inclined to the horizon were at one time parallel to the horizon." Steno, 1669     

Photograph by Kevin Hefferan

This photograph illustrates the horizontal beds of the Oligocene Age White River Group, exposed in Badlands National Park. Note that the individual bed layers are horizontal and have not been tilted or folded since their deposition 25-35 Ma.

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