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SxMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 78 



Fig. 48. — Beds of Hamilton age at 18-Mile Creek. The protruding band is 

 the Encrinal limestone, which separates the lower from the upper Hamilton. 

 Section 7, 18-Mile Creek, N. Y. (Photograph hv E. R. Pohl.) 



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-~-_* IV 



Fig. 49. — Section of the middle Devonian shales at No. 4 Hill, Arkona, 

 Ontario, Canada. The beds are divided into lower and upper Hamilton by 

 the Encrinal limestone in the middle foreground. (Photograph by E. R. Pohl.) 



