BULL. GEOL. SOC. AM. 



VOL. 17, 1905, PL. 5 



CREST OF MISSION RANGE, MONTANA 



This view, taken a short distance south ol 

 altered calcareous and sil 



Mount McDonald, shows the effect of glacial erosion on the slightly 

 iceous beds of the Blackfoot series. C. D. YV., l'JUO 



