inconsiderable. The snow water is yielded to the earth, from which it
has helped to withdraw the frost, so that in the springtime, the
growing season of plants, the ground contains an ample store of
moisture for their development. Where the snowfall accumulates to a
great thickness, especially where it lodges in forests, the influence
of the icy covering is somewhat to protract the winter and thus to
abbreviate the growing season.

Where snow rests upon a steep slope, and gathers to the depth of
several feet, it begins to creep slowly down the declivity in a manner
which we may often note on house roofs. This motion is favoured by the
gradual though incomplete melting of the flakes as the heat
penetrates the mass. Making a section through a mass of snow which has
accumulated in many successive falls, we note that the top may still
have the flaky character, but that as we go down the flakes are
replaced by adherent shotlike bodies, which have arisen from the
partial melting and gathering to their centres of the original
expanded crystalline bits. In this process of change the mass can move
particle by particle in the direction in which gravity impels it. The
energy of its motion, however, is slight, yet it can urge loose stones
and forest waste down hill. Sometimes, as in the cemetery at Augusta,
Me., where stone monuments or other structures, such as iron railings,
are entangled in the moving mass, it may break them off and convey
them a little distance down the slope.

So long as the summer sun melts the winter's snow, even if the ground
be bare but for a day, the role of action accomplished by the snowfall
is of little geological consequence. When it happens that a portion of
the deposit holds through the summer, the region enters on the glacial
state, and its conditions undergo a great revolution, the consequences
of which are so momentous that we shall have to trace them in some
detail. Fortunately, the considerations which are necessary are not
recondite, and all the facts are of an extremely picturesque nature.

Taking such a region as New England, where all the earth is
life-bearing in the summer season, and where the glacial period of the
winter continues but for a short time, we find that here and there on
the high mountains the snow endures throughout most of the summer, but
that all parts of the surface have a season when life springs into
activity. On the top of Mount Washington, in the White Mountains of