BULL. GEOL. SOC. AM. 



VOL. 21, 1909, PL. 18 





ite, ; 







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Figure 1. — Rock Bridge across Swifts Camp Creek^ near Campton^ Kentucky 

 Formed by the perforation of an incised meander. (See text figure 1) 



Figure 2. — Natural Bridge in Bad Lands of South Dakota 



This bridge, which is south of White River below the mouth of Porcupine Creek, was 

 formed by the perforation of an incised meander. Photograph by Mr. Barnett from 

 point "x." 



ILLUSTRATIONS OF NATURAL ROCK BRIDGES 



