Monument Rocks (Kansas)

Monument Rocks (also Chalk Pyramids) are a series of large chalk formations in Gove County, Kansas, rich in fossils. The formations were the first landmark in Kansas chosen by the U.S. Department of the Interior as a National Natural Landmark. The chalk formations reach a height of up to 70 ft (21 m) and include formations such as buttes and arches. The carbonate deposits were laid down during the Cretaceous Period in what was then the Western Interior Seaway, which split the continent of North America into two landmasses. They are estimated to have been formed 80 million years ago.

On January 29, 2008, Monument Rocks, 25 miles south of Oakley, Kansas, and Castle Rock, 31 miles to the east, were jointly named as one of the 8 Wonders of Kansas.

Other geological formations in Kansas: