r part of this country, having of late much
harassed the outlying estancias, the government at Buenos Ayres
equipped some time since an army under the command of General Rosas
for the purpose of exterminating them. The troops were now encamped
on the banks of the Colorado; a river lying about eighty miles
northward of the Rio Negro. When General Rosas left Buenos Ayres he
struck in a direct line across the unexplored plains: and as the
country was thus pretty well cleared of Indians, he left behind
him, at wide intervals, a small party of soldiers with a troop of
horses (a posta), so as to be enabled to keep up a communication
with the capital. As the "Beagle" intended to call at Bahia Blanca,
I determined to proceed there by land; and ultimately I extended my
plan to travel the whole way by the postas to Buenos Ayres.

AUGUST 11, 1833.

Mr. Harris, an Englishman residing at Patagones, a guide, and five
Gauchos who were proceeding to the army on business, were my
companions on the journey. The Colorado, as I have already said, is
nearly eighty miles distant: and as we travelled slowly, we were
two days and a half on the road. The whole line of country deserves
scarcely a better name than that of a desert. Water is found only
in two small wells; it is called fresh; but even at this time of
the year, during the rainy season, it was quite brackish. In the
summer this must be a distressing passage; for now it was
sufficiently desolate.

The valley of the Rio Negro, broad as it is, has merely been
excavated out of the sandstone plain; for immediately above the
bank on which the town stands, a level country commences, which is
interrupted only by a few trifling valleys and depressions.
Everywhere the landscape wears the same sterile aspect; a dry
gravelly soil supports tufts of brown withered grass, and low
scattered bushes, armed with thorns.

Shortly after passing the first spring we came in sight of a famous
tree, which the Indians reverence as the altar of Walleechu. It is
situated on a high part of the plain; and hence is a landmark
visible at a great distance. As soon as a tribe of Indians come in
sight of it, they offer their adorations by loud shouts. The tree
itself is low, much branched, and thorny: just above the root it
has a diameter of about three feet. It stands by itself without any
neighbour, and was indeed the first tree we saw; afterwards we met
with a few others of the same kind, but they were far fr