slum is now competent to "fight the wilderness" out there, with his
eight-shilling fowling-piece and the implements of his trade. The
barbarians no longer exist to frighten his soul with dreadful war cries;
they have moved away to another more remote and shadowy region, called
in their own language _Alhuemapu_, and not known to geographers. For
the results so long and ardently wished for have swiftly followed on
General Roca's military expedition; and the changes witnessed during the
last decade on the pampas exceed in magnitude those which had been
previously effected by three centuries of occupation.

In view of this wave of change now rapidly sweeping away the old
order, with whatever beauty and grace it possessed, it might not seem
inopportune at the present moment to give a rapid sketch, from the field
naturalist's point of view, of the great plain, as it existed before the
agencies introduced by European colonists had done their work, and as it
still exists in its remoter parts.

The humid, grassy, pampean country extends, roughly speaking, half-way
from the Atlantic Ocean and the Plata and Parana rivers to the Andes,
and passes gradually into the "Monte Formation," or _sterile pampa_--a
sandy, more or less barren district, producing a dry, harsh, ligneous
vegetation, principally thorny bushes and low trees, of which the chanar
(Gurliaca decorticans) is the most common; hence the name of
"Chanar-steppe" used by some writers: and this formation extends
southwards down into Patagonia. Scientists have not yet been able to
explain why the pampas, with a humid climate, and a soil exceedingly
rich, have produced nothing but grass, while the dry, sterile
territories on their north, west, and south borders have an arborescent
vegetation. Darwin's conjecture that the extreme violence of the
_pampero,_ or south-west wind, prevented trees from growing, is now