cter: they result from the pressure of snow into a crystalline
mass in a mountain valley: and they must have remained there unmelted
ever since the close of the Glacial epoch, which, by Dr. Croll's
calculations, must most probably have ceased to plague our earth some
eighty thousand years ago. Modern America, however, has no respect for
antiquity: and it is at present engaged in using up this palaeocrystic
deposit--this belated storehouse of prehistoric ice--in the manufacture
of gin slings and brandy cocktails.

As one scales a mountain of moderate height--say seven or eight
thousand feet--in a temperate climate, one is sure to be struck by the
gradual diminution as one goes in the size of the trees, till at last
they tail off into mere shrubs and bushes. This diminution--an old
commonplace of tourists--is a marked characteristic of mountain plants,
and it depends, of course, in the main upon the effect of cold, and of
the wind in winter. Cold, however, is by far the more potent factor of
the two, though it is the least often insisted upon: and this can be
seen in a moment by anyone who remembers that trees shade off in just
the self-same manner near the southern limit of permanent snow in the
Arctic regions. And the way the cold acts is simply this: it nips off
the young buds in spring in exposed situations, as the chilly
sea-breeze does with coast plants, which, as we commonly but
incorrectly say, are "blown sideways" from seaward.

Of course, the lower down one gets, and the nearer to the soil, the
warmer the layer of air becomes, both because there is greater
radiation, and because one can secure a little more shelter. So, very
far north, and very near the snow-line on mountains, you always find
the vegetation runs low and stunted. It takes advantage of every crack,
every cranny in the rocks, every sunny little nook, every jutting point
or wee promontory of shelter. And as the mountain plants have been
accustomed for ages to the strenuous conditions of such cold and
wind-swept situations, they have ended, of course, by adapting
themselves to that station in life to which it has pleased the powers
that be to call them. They grow quite naturally low and stumpy and
rosette-shaped: they are compact of form and very hard of fibre: they
present no surface of resistance to the wind in any way; rounded and
boss-like, they seldom rise above the level of the rooks and stones,
whose interstices they occupy. It is this combin