COLLAPSE OF MOUNTAIN SUMMITS 

 By George J. Young 



IN August, 192 1, I had the good fortune to make a trip through 

 the Whitney, Kern, and Kings river region, entering from Lone 

 Pine and leaving at Bishop. The snow conditions were such that 

 many details of topography which in other years would have escaped 

 attention were noticeable. In descending from Tyndall Pass to the 

 cirque below on the east, several large talus-piles were noted. The 

 rocks in one of these were of large size. There was little doubt that 

 the pile had resulted from the collapse of one of the peaks on the 

 east wall contiguous to the Tyndall Creek Valley. Two other talus- 

 piles were undoubtedly of similar origin. In ascending to Junction 

 Pass, a small talus-pile was observed on the left of the trail, and 

 this also was formed by the sudden letting go of a pinnacle on the 

 eastern scarp. 



No other instances were noted until we ascended the Middle Fork 

 of the Kings. Between Cartridge and Palisade creeks the trail 

 passes around a prominent peak on the right-hand side through an 

 immense pile of talus, the individual blocks of which are of very 

 large size. Without much doubt the peak formerly overhung and the 

 overhanging portion let go, falling down a comparatively short dis- 

 tance and breaking into large pieces. There was little opportunity 

 for a "run," and, consequently, the large blocks were not reduced 

 to the condition ordinarily found in talus. 



No other instances were noted until we descended from Piute 

 Pass down Bishop Creek. Old Tom Mountain forms one of the 

 prominent peaks on the east scarp, north of Bishop Creek. The top 

 of this peak caved and the debris fell several thousand feet, reaching 

 equilibrium in a small meadow west of a lake and forming a rock- 

 dump at the toe of the mountain slope. This deposit is flat-topped 

 and looks like a mine-dump. The rock pieces were reduced to com- 

 paratively small size. Looking up from the meadow to the top of 

 the mountain, the channel carved out by the falling avalanche of 

 rock is distinctly noticeable. At two higher points are dumps which 



