County: Ottawa

Date: May 2003

Photographer: Liz Brosius/KGS

Place Name: Rock City

Short description: Sandstone concretions at Rock City in Ottawa County. Sandstone spheres up to 20 feet in diameter cover an area roughly the size of two football fields at Rock City. Known as concretions, the spheres weathered out of a sandstone layer in the Dakota Formation. The sandstone formed mainly from sand deposited along the edge of a sea that covered the western half of Kansas during the Cretaceous Period.

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