BULL. GEOL. SOC. AM. 



VOL. 17, 1905, PL. 7 



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Figure 1. — Cuff of typical, banded, arenaceois and siliceous Shai.es of Spokane Formation 

 Belt terrane, on Wolf creek, 2 miles below Mitchell, Big Belt mountains, Montana. C. D. W., 1900 





Figure 2. — Surface of upturned Beds of Quartzite 



Three systems of jointing are shown. Greyson shales, Belt terrane, Deep Creek canyon, 14 miles 

 east of Townsend, Big Belt mountains, Montana. C. D. W., 1898 



SPOKANE SHALES AND QUARTZITE BEDS OF GREYSON FORMATION 



