The Ouachita Mountains extend 186 miles east and west, between Little Rock (Pinnacle Mountain), Arkansas, and Atoka, Oklahoma. Lying south of the Arkansas River and the Ozark Mountains, the Ouachitas include Mount Magazine, Petit Jean, Nebo Mountain, the Fourche Range, the Cossatot Range, Black Fork Mountain, Jackfork Mountain and the Potato Hills. Rich Mountain and Winding Stair Mountain are among the highest points in Arkansas and Oklahoma.

Composed mostly of sandstone and shale, the Ouachitas are the result of extreme lateral pressure, causing tight folding and faulting. Due to erosion, these mountains stand about one-third of their original height.

Several geological faults are located along the Talimena Byway. The Winding Stair fault extends along the lower south face of Rich Mountain. The Honess Fault forms the valley of Big Creek between Rich Mountain and Black Fork Mountain. Briery Creek follows Briery Fault to the north of Black Fork Mountain. The fault then cuts between the west end of Rich Mountain and Spring and Honess Mountains, dissecting the Robert S. Kerr Arboretum tract.

You may find references to rock glaciers along the drive. These are not true “glaciers.” One theory believes that many years ago, these rock flows may have had ice cores. The south slope of Black Fork Mountain exemplifies these formations.