606 ALLEN DAVID HOLE 
In the south-central and southeastern part of the basin large 
angular bowlders up to 15 feet in diameter are scattered over an 
area of half a square mile or more. These bowlders do not appear 
to be a part of the talus slope which lies just at the base of the 
precipitous rock wall which bounds the basin, but, from their 
somewhat uniform distribution and lack of gradation in size as 
distance from the cliff face increases, seem to be fragments carried 
to their present position by the ice. Below about 12,000 feet in 
elevation the main valley is comparatively narrow, and U-shaped 
in cross-section. 
The channel of the stream in places consists of a narrow gorge 
to to 20 feet deep in the bed rock; in other places it occupies the 
bottom of the U-shaped cross-section, giving no evidence of having 
lowered its bed appreciably since the withdrawal of the ice. The 
amount of post-glacial erosion by the stream may, therefore, be 
stated as 10 to 20 feet, in the most favorable locations. 
The valley is in general well cleaned out; roches moutonneées, 
with abundant striae, are found at many points, the striae being in 
general approximately parallel to the course of the stream. Some 
striated surfaces are found on the under side of overhanging ledges 
which project one or two feet from a nearly vertical cliff face. At 
about 11,000 feet in elevation, near the trail east of the stream, a 
striated groove occurs in the nearly perpendicular wall of rock 
forming the side of the valley. At elevation about 10,700 feet, near 
the stream, and again a little farther southeast at 11,000 feet, 
near the trail, pot holes were observed. Each is on the north side 
of a steep, smooth face of rock in place. The location is such as 
would result if rock in which a perfect pot hole exists were worn off 
diagonally across the pot hole, leaving on the steep slope only a 
trace of the top, while the bottom, still complete, remained wholly 
back of the sloping face. 
Bridal Veil basin has the following tributary basins: (a) on the 
east, (1) East basin, (2) Mud Lake basin, and (3) Gray’s basin; (0) 
on the west, (1) Jackass basin, and (2) Silver Lake basin. 
East basin.—This basin, above 12,300 feet in elevation, has a 
comparatively flat bottom and contains a lake lying in a rock basin, 
which has been converted into a reservoir, increasing its size until 
