bed of the river. If I had space I could prove that South
America was formerly here cut off by a strait joining the
Atlantic and Pacific oceans, like that of Magellan. But it
may yet be asked, how has the solid basalt been removed ?
Geologists formerly would have brought into play, the
violent action of some overwhelming debacle; but in this
case such a supposition would have been quite inadmissible;
because the same step-like terraces, that front the Patagonian
coast, sweep up on each side of the valley. No possible
action of any flood could have thus modelled the land in
these two situations ; and by the formation of such terraces
the valley itself has been hollowed out. Although we know
that there are tides, which run within the narrows of the
Strait of Magellan at the rate of eight knots an hour, yet we
must confess it makes the head almost giddy to reflect on the
number of years, century after century, which the tides
unaided by a heavy surf, must have required to have corroded
so vast an area and thickness of solid rock. Nevertheless,
we must believe that the strata undermined by the
waters of this ancient strait, were broken up into huge fragments,
and there lying scattered on the beach, were reduced
to smaller blocks, then to pebbles, and lastly to the most
impalpable mud, which the tides drifted into the bed, either
of the Eastern or Western Ocean.
With the change in the geological structure of the plains
the character of the landscape likewise altered. While
rambling up some of the narrow and rocky defiles, I could
almost have fancied myself transported back again to the
barren valleys of St. Jago. Among the basaltic cliffs, I found
some plants which I had seen nowhere else, but others I
recognised as being wanderers from Tierra del Fuego. These
porous rocks serve as a reservoir for the scanty rain-water,
and consequently on the line where the igneous and sedimentary
formations unite, several small springs (most rare
occurrences in Patagonia) burst forth; and they could be
distinguished at a distance by the circumscribed patch of
bright green herbage.
A p r i l 27t h . — The bed of the river became rather narrower,
and hence the stream more rapid. It here ran at the
rate of six knots an hour. From this cause, and from the
many great angular fragments, tracking the boats became
both dangerous and laborious.
This day I shot a condor. It measured from tip to tip of
the wings, eight and a half feet, and from beak to tail, four feet.
I t is a magnificent spectacle to behold several of these great
birds seated on the edge of some steep precipice. I will here
describe all I have observed respecting their habits. The
condor is known to have a wide geographical range, being
found on the west coast of South America, from the Strait of
Magellan throughout the entire range of the CordiUera. On
the Patagonian shore, the steep cliff near the mouth of the Rio
Negro in lat. 41°, was the most northern point where I saw
these birds, or heard of their existence. They have there
wandered about four hundred miles from the great central
line of their habitation in the Andes. Further south, among
the bold precipices which form the head of Port Desire, they
are not uncommon; yet only a few stragglers occasionally
visit the sea-coast. A line of cliff near the mouth of St. Cruz,
is frequented by these birds, and about eighty miles up the
river, where first the sides of the valley were formed by
steep basaltic precipices, the condor again appeared, although
in the intermediate space not one had been seen. From
these and similar facts, the presence of this bird seems
chiefly to be determined by the occurrence of perpendicular
cliffs. In Patagonia, the condors either by pairs or many
together, both sleep and breed on the same overhanging
ledges. In Chile, during the greater part of the year, they
haunt the lower country near the shores of the Pacific,
and at night several roost in one tr ee ; but in the early part
of summer, they retire to the most inaccessible parts of the
inner Cordillera, there to breed in peace.
With respect to their propagation, I was told by the
country people in Chile, that the condor makes no sort of