Monument Rocks (also chalk pyramids ) are a series of large chalk formations in Gove County, Kansas, USA. They contain many fossils. The formations were the first landmark selected as a National Natural Landmark by the United States Department of the Interior. The chalk formations reach up to 70 feet (21 m) in height. They include formations such as buttes and arches. The carbonate deposits were formed during the Cretaceous Period in what was then the Western Interior Seaway. It divided the continent of North America into two continents. They are estimated to have formed 80 million years ago.
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| Monument Rocks Kansas USA |
On January 29, 2008, Monument Rocks, located 25 miles south of Oakley, Kansas, and Castle Rock, 31 miles to the east, were collectively named one of the 8 Wonders of Kansas.