SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE SHERZER. 



PLATE XIX. 



FIG. I. Boulder mound, Wenkchemna Glacier, illustrating the protective effect of rocky debris. Estimated to be 



eighty feet in height. 



Whyte. Devil's Thumb. 



Bow Valley. 



Fairview. 



FIG. -2. Surface lakelet, Victoria Glacier, resulting from lack of debris protection. Enlargement towards right is still 

 in progress by melting, but has practically ceased towards the left, owing to the rocky cover. 



