unk,
may be regarded as a dam hoarding the bounty of storm-clouds, and
dispensing it as blessings all through the summer, instead of allowing
it to go headlong in short-lived floods. Evaporation is also checked by
the dense foliage to a greater extent than by any other Sierra tree, and
the air is entangled in masses and broad sheets that are quickly
saturated; while thirsty winds are not allowed to go sponging and
licking along the ground.

So great is the retention of water in many places in the main belt, that
bogs and meadows are created by the killing of the trees. A single trunk
falling across a stream in the woods forms a dam 200 feet long, and from
ten to thirty feet high, giving rise to a pond which kills the trees
within its reach. These dead trees fall in turn, thus making a clearing,
while sediments gradually accumulate changing the pond into a bog, or
meadow, for a growth of carices and sphagnum. In some instances a series
of small bogs or meadows rise above one another on a hillside, which are
gradually merged into one another, forming sloping bogs, or meadows,
which make striking features of Sequoia woods, and since all the trees
that have fallen into them have been preserved, they contain records of
the generations that have passed since they began to form.

Since, then, it is a fact that thousands of Sequoias are growing
thriftily on what is termed dry ground, and even clinging like mountain
pines to rifts in granite precipices; and since it has also been shown
that the extra moisture found in connection with the denser growths is
an effect of their presence, instead of a cause of their presence, then
the notions as to the former extension of the species and its near
approach to extinction, based upon its supposed dependence on greater
moisture, are seen to be erroneous.

The decrease in the rain- and snow-fall since the close of the glacial
period in the Sierra is much less than is commonly guessed. The highest
post-glacial watermarks are well preserved in all the upper river
channels, and they are not greatly higher than the spring floodmarks of
the present; showing conclusively that no extraordinary decrease has
taken place in the volume of the upper tributaries of post-glacial
Sierra streams since they came into existence. But in the mean time,
eliminating all this complicated question of climatic change, the plain
fact remains that _the present rain- and snow-fall is abundantly
sufficient for the