n way before the glacial pressure, as well as small particles;
moraines, too, some scattered, others regular like long curving
embankments and dams, occur here and there, giving the general surface
of the region a young, new-made appearance. I watched the gradual
dwarfing of the pines as I ascended, and the corresponding dwarfing of
nearly all the rest of the vegetation. On the slopes of Mammoth
Mountain, to the south of the pass, I saw many gaps in the woods
reaching from the upper edge of the timber-line down to the level
meadows, where avalanches of snow had descended, sweeping away every
tree in their paths as well as the soil they were growing in, leaving
the bedrock bare. The trees are nearly all uprooted, but a few that had
been extremely well anchored in clefts of the rock were broken off near
the ground. It seems strange at first sight that trees that had been
allowed to grow for a century or more undisturbed should in their old
age be thus swished away at a stroke. Such avalanches can only occur
under rare conditions of weather and snowfall. No doubt on some
positions of the mountain slopes the inclination and smoothness of the
surface is such that avalanches must occur every winter, or even after
every heavy snowstorm, and of course no trees or even bushes can grow in
their channels. I noticed a few clean-swept slopes of this kind. The
uprooted trees that had grown in the pathway of what might be called
"century avalanches" were piled in windrows, and tucked snugly against
the wall-trees of the gaps, heads downward, excepting a few that were
carried out into the open ground of the meadows, where the heads of the
avalanches had stopped. Young pines, mostly the two-leaved and the
white-barked, are already springing up in these cleared gaps. It would
be interesting to ascertain the age of these saplings, for thus we
should gain a fair approximation to the year that the great avalanches
occurred. Perhaps most or all of them occurred the same winter. How glad
I should be if free to pursue such studies!

Near the summit at the head of the pass I found a species of dwarf
willow lying perfectly flat on the ground, making a nice, soft, silky
gray carpet, not a single stem or branch more than three inches high;
but the catkins, which are now nearly ripe, stand erect and make a
close, nearly regular gray growth, being larger than all the rest of the
plants. Some of these interesting dwarfs have only one catkin--willow
b