

EXPLANATION OF PLATE VI 



UPPER FIGURE. PROFILE OF HIDDEN GLACIER 



Shows the relation of the glacier snout in June, 1899, to topo- 

 graphic details of the south wall of the valley. In the foreground are 

 bedded gravels that have been overridden, eroded, and grooved by the 

 enlarged glacier, and are now being trenched by running water. 



The amphitheater high in the mountain shows familiar forms of 

 aqueous sculpture but is not continued downward in a gorge of com- 

 mensurate size. The gorge probably once existed, but the containing 

 spurs were removed by ice erosion at a time when the glacier was much 

 larger than now. 



See page 52, and compare figure 28. 



Photographed by G. K. Gilbert, June 20, 1899. Negative NO. 368, 

 United States Geological Survey. 



LOWER FIGURE. SECTION OF MORAINE 



Shows the structure of one of the ridges of the northern lateral mo- 

 raine of Hidden Glacier. See page 56. 



Photographed by G. K. Gilbert. Negative NO. 370, United States 

 Geological Survey." 



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