. "Monument Rocks (also Chalk Pyramids) are a series of large chalk formations in Gove County, Kansas, rich in fossils. It is a National Natural Landmark. It was the first landmark chosen by the US Department of the Interior as a national natural landmark. The chalk formations reach a height of up to 70 ft. and include formations such as buttes and arches."@en . . . . . . . "Monument Rocks"@en . . . "Niobrara Chalk(erosional remnant)" . "802.0"^^ . . . . . . "Late Cretaceous" . .