EVIDENCE FROM BLOODY AND LUNDY CANYONS 89 



Lundy canyon, present certain similarities and contrasts which are in- 

 structive in the above connection. These two canyons are only about 5 

 miles apart, are situated on the same side of a mountain range, and 

 hence must have been subjected to the same climatic changes. They 

 have been excavated in rocks of essentially the same degree of resistance 

 to mechanical erosion and were in each instance occupied by a glacier 

 which extended beyond the lower limit of its canyon and entered Mono 

 valley — the Lundy Canyon glacier reaching out half a mile and Bloody 

 Canyon glacier between 3 and 4 miles into the main valley. Bloody 

 canyon has a steep gradient, is about 2 miles long, approximately 2,000 

 to 2,500 feet deep, and a mile wide at an elevation of 2,000 feet above its 

 bottom. Lundy canyon is 6 to 7 miles long, has a gentle gradient in 

 its lower half, is steep in its upper portion, and about 3,000 feet deep, 

 with a width of approximately 1J- miles at an elevation of 2,000 feet 

 above its bottom. The amount of material removed in order to produce 

 Lundy canyon was certainly five times as great as the similar task in the 

 case of Bloody canyon. If each canyon was excavated by a glacier, it 

 is entirely consistent to conclude that the morainal material deposited 

 by Lundy Canyon glacier should be at least five times as great as the 

 similar material laid down by Bloody Canyon glacier. On the contrary, 

 however, as shown by field observation and an inspection of carefully 

 prepared maps, the recognizable morainal material in Lundy canyon and 

 about its mouth is in volume only a small per cent of the volume of the 

 similar material in and in front of Bloody canyon. The morainal em- 

 bankments at the mouth of Lundy canyon are simple ridges about half 

 a mile long and between 200 and 300 feet high. The similar embank- 

 ments at the mouth of Bloody canyon are over 3 miles long, highly 

 compound, and for a distance of over a mile near their source of supply 

 are between 500 and 600 feet higher than the bottom of the trough 

 between them, which itself has a thick accumulation of morainal and 

 stream-deposited material beneath it. 



It is thus made clear that the amount of work the Bloody Canyon 

 glacier performed was vastly greater than the work done by Lundy 

 Canyon glacier. Why this discrepany in the case of two neighboring 

 glaciers of approximately the same size and working on essentially the 

 same average character of rock ? The only explanation which seems to 

 fit the case is that Lundy canyon had approximately its present size and 

 shape previous to the origin of the glacier which occupied it, and that 

 the glacier found the canyon, especially in its lower half, so well adapted 

 for its use that but slight alterations were made in its contours, while 

 Bloody Canyon glacier originated where only a comparatively small 

 amount of previous excavation had been done, and it eroded its bed 

 vigorously. 



