332 J. LeConte—Ancient Glaciers of the Sierras. 
Between the cliff 5 6 6 and the snow, there is an empty space 
like a crevasse, 4 to 5 feet wide, evidently produced by the tear- 
ing away of the moving snow from the perpendicular cliffs. 
In the language of Alpine travelers, it is a bergschrund. Mr. 
Muir has also found a crevasse several feet wide in a similar 
snow field on Mt. McClure. 
34 inches, and No. 4 which was near the middle, 47 inches.* 
Both the fact of motion and its differential character are therefore 
certain. 
in its feeble old age—feeble remnants of the great Tuolumne 
glacier—a glacier once of grand proportions and playing an 
important part in mountain sculpture, but now in its second 
childhood. 
Mr. Muir tells me that he has found, hiding away among 
Before leaving the subject of Mt. Lyell glacier (if I might 
so call it), there is another point to which I would call the 
in the direction of slope would be somewhat like the adjoiming 
gure imbing up 
the slope over these ice 
lades was certainly the 
most difficult climbing 
I have ever attempted. 
Stepping from blade to 
blade, was attended with 
great risk of repeated 
* An account of these experimen thly, will be 
found in thin Journal for Jan Honrgersth=ry ore elt ep ptener et 
