HANGING VALLEYS OF 7 HE YOSEMITE 



549 



The overlapping gorge of the Vernal fall is not so long as 

 that of the Nevada fall, and for some reason it is on the south 

 side of the stream. 



These explanations also show why the Upper Yosemite fall is 

 not in the deep gorge that cuts back into the north wall of the 

 valley on the west side of the stream. The stream follows the 

 axis of the original valley ; the gorge just west of it was cut 

 toward the close of the glacial epoch by a stream that was 

 crowded to one side by the great glacier that filled the main 



Fig. 3. — Sketch to show how the stream above Nevada Fall was crowded north- 

 ward by the ice (shaded area), and how it cut a gorge past the present position of 

 Neva-ia.Fall. 



valley. For the glacier that came down Yosemite Creek was 

 fully ten miles long above the site of the present Yosemite fall. 



It is quite probable that other notches in the canyon walls 

 near these high falls from the hanging valleys have had a simi- 

 lar origin. 



In each of these cases it is evident that the cutting done by 

 the stream was much more rapid than that done by the ice, for 

 in every instance the stream gained upon the glacier until the 

 two channels overlapped each other. 



If the explanation here offered for these peculiar forms be 

 correct, it may well be asked why there is no such feature at the 

 Bridal Veil fall, for this last apparently has no such overlapping 

 canyon, while its position and history is otherwise similar to those 

 of the other falls around the Yosemite valley. On the west side 



