Iyawakagapi

The Cannonball River rises in the badlands of western North Dakota and flows east toward the Missouri. Its Lakota name, Íŋyaŋwakağapi Wakpá, refers to the remarkable round stones found in the region. These sandstone concretions formed when minerals cemented grains together within softer sediments; erosion subsequently exposed them. The river's upper basin is a country of dissected plateaus and isolated buttes.