e shade of dwarfed and desiccated cedars we look vainly
for the snowy or azure bells of the three-petalled campanula. Gaunt,
staring sunflowers, and humbler _compositae_ of yellow tinge, stay with
us a little longer than those darlings of our earlier scenery; but
before we have gone many miles the last conspicuous wave of fresh
vegetation breaks hopelessly on a thirsty sand-hill, and we are given
over to a wilderness of cacti. Here and there occurs a sightly clump of
waxen yellow blossoms, where these vegetable hedgehogs are in their
holiday attire,--but it must be confessed that the view is a melancholy
change from our recent affluence of beauty. With the other succulent
plants, the rich herbage of the prairie has entirely disappeared. There
is not a blade of anything which an Eastern grazier would recognize as
grass between this boundary and the Rocky Mountains. As we whiz over
these wastes at railroad-speed, we shall be apt to pronounce them
absolutely sterile. When we stop at the next coaling-station, let us
examine the matter more closely. The ground proves to be covered with
minute gray spirals of herbage, like a crop of vegetable corkscrews, an
inch or two in height, and to all appearance dry as wool. This is the
"_grama_" or "buffalo-grass," and, despite its look of utter
desiccation, is highly nutritious. It is almost the entire winter
dependence of the buffalo-herds, and domestic cattle soon learn to
prefer it to all other feed. Its existence, together with the wide group
of changes which we have noticed, denotes that we have passed the
threshold of the fourth grand continental division, and are now in the
region of the Plains proper.

Ex-Governor Gilpin of Colorado, in his "Central Gold Region," very truly
styles the Plains "the pastoral area of the continent." The Plains are
set apart for grazing purposes by the method of exclusion. There is
nothing else that can be done with them. Rain seldom falls on them. The
shallow rivers, like the Platte, which wander through them, are too far
apart to be used economically for their general irrigation. Only such
herbage may be expected to thrive here as can live on its own
condensation of water from a sensibly dry atmosphere. Manifestly, art
can do nothing for the improvement of such a tract. It must be left to
fulfil its natural function, as the great continental pasture. Along the
banks of the rivers run narrow strips of alluvial soil, liable to yearly
inundation; an