Two Top and Big Top Mesa

Two Top and Big Top Mesa are two adjacent mesas that are approximately 1 mi apart in western North Dakota. They were declared National Natural Landmarks in 1965. The tops of the mesas are rare examples of undisturbed grassland which have never been grazed or cultivated. They are located in or around the Little Missouri National Grasslands.

Geology
Big Top mesa is approximately 12 acre, while Two Top is around 2 acre. They rise about 400 ft above the badlands. They are made of sandstone, Morton silt loam and clay.