start inland, and travel right on, burying a house or farm if it be in
the way, but resurrecting it again on the other side as the hill goes
on. Anyone may see these hills at the south end of Lake Michigan, as
he approaches Chicago, west of San Francisco, all along up the Columbia
River--the sand having come on the wings of the wind from the coast.

But to see the whole visible world on a march one needs to go to a
really large desert. The Pyramids and the Sphinx have been partly
buried, and parts of the valley of the Nile threatened, by hordes of
sand hills marching in from the desert; cities have been buried and
harbors filled up. Many of the harbors of the ancient civilizations
are mere miasmatic marshes now. This is partly in consequence of the
silt brought in by the rivers; but where the rivers do not flow in it
is because the sand blows in along the shore. Harbors are especially
endangered when their protection from the waves consists of a bank of
sand, as on Cape Cod and the Sandy Hook below the Narrows of the harbor
of New York.

How can man combat part of the continent on the move, driven by the
ceaseless powers of the air? By a humble plant or two. The movement
of the sand hills that threaten to destroy the marvelous beauty of the
grounds of the Hotel del Monte at Monterey is stopped by planting dwarf
pines. The sand dunes that prevent much of Holland from being
reconquered by the sea are protected with great care by willows, etc.,
and the coast sands of parts of eastern France have been sown with sea
pine and broom.

The tract of a thousand acres on Cape Cod had been protected by humble
beach grass. Some careless herder let the cows eat it in places, and
away went part of a township. It is now a punishable crime on Cape Cod