Near the lower end of the lake a somewhat obscure branch ridge comes off from each main ridge, and curving around it forms an imperfect terminal moraine through which the outlet of the lake breaks its way.
[Footnote 2: Professor Price informs me there is a difference of eighty feet between the level of Lake Tahoe and Fallen Leaf Lake.] On ascending the canyon the glaciation is very conspicuous, and becomes more and more beautiful at every step.

From Glen Alpine Springs upward it is the most perfect I have ever seen.
In some places the white rocky bottom of the canyon, for many miles in extent, is smooth and polished and gently undulating, like the surface of a glassy but billowy sea.

The glaciation is distinct also up the sides of the canyon 1000 feet above its floor.
There can be no doubt, therefore, that a glacier once came down this canyon filling it 1000 feet deep, scooped out Fallen Leaf Lake just where it struck the plain and changed its angle of slope, and pushed its snout four miles out on the level plain, nearly to the present shores of Lake Tahoe, dropping its debris on either side and thus forming a bed for itself.
In its subsequent retreat it seems to have rested its snout some time at the lower end of Fallen Leaf Lake, and accumulated there an imperfect terminal moraine.
_Cascade Lake Glacier_.

Cascade Lake, like Fallen Leaf Lake, is about one and one-half miles from Lake Tahoe, but, unlike Fallen Leaf Lake, its discharge creek has considerable fall, and the lake surface is, therefore, probably 100 feet above the level of the greater lake.

On either side of this creek, from the very border of Lake Tahoe, runs a moraine ridge up to the lake, and thence along each side of the lake up to the rocky points which terminate the true mountain canyon above the head of the lake.