As the eye sweeps again up the canyon-beds,
little lakes, glacier scooped rock basins, filled with
ice-cold water, flash in the sunlight on every side. Twelve or
fifteen of these may be seen.
From appropriate positions on the surface of Lake Tahoe, also,
all the moraine ridges are beautifully seen at once, but the
glacial lakes and the canyon-beds, of course, cannot be seen.
There are several questions of a general nature suggested by
my examination of these three glacial pathways, which I have
thought best to consider separately.
_a. Evidences of the existence of the Great Lake Valley
Glacier_. On the south shore of Lake Tahoe, and especially
at the northern or lower end of Fallen Leaf Lake, I found
many pebbles and some large bowlders of a beautiful striped
agate-like slate. The stripes consisted of alternate bands
of black and translucent white, the latter weathering into
milk-white, or yellowish, or reddish. It was perfectly evident
that these fragments were brought down from the canyon above
Fallen Leaf Lake. On ascending this canyon I easily found the
parent rock of these pebbles and bowlders.
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