South Dakota School of Mines 



Bulletin No. 13. Plate No. 76. 



Photograph by O'Harra, 1918. 



A. General view of Slim Buttes, Perkins county, South Dakota, capped 

 by White River Tertiary deposits. 









v." 



"-* 4^S^« 





Photograph by O'Harra, 1918. 



B. Detail of the southern end of South Cave Hills, Harding county, 

 South Dakota. Shows Fort Union sandstone of earlier Tertiary age 

 than the White River Beds. 



