South Dakota School of Mines Bulletin No. 13. Plate No. 57. 



Photograph by O'Harra. 1911. 



A. Detail of the Great Wall north of Interior. 



Photograph by O'Harra, 1912. 



B. The Great Wall at Cedar Pass northeast of Interior. A roadway suit- 

 able for automobiles winds up this slope and reaches the top at the 

 lowest skyline depression to the left of the center. See Plate 88. 



