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Show 218 PATAGONIA. April, 1834. 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 be!ieve 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. J ago. 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. April, 1834. CONDOR. 219 APRIL 27TH.-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. It 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 Cordillera. 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 interm~diate 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 tree; but in the early part of summer, they retire to the most inaccessi~le 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 |