182 S. CRUZ, PATAGONIA. [CHAP. ix. 



ments, and these lying scattered on the beach, were reduced first 

 to smaller blocks, then to pebbles, and lastly to the most impal- 

 pable mud, which the tides drifted far into 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 01 

 the island 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, 

 some small springs (most rare occurrences in Patagonia) burst 

 forth ; and they could be distinguished at a distance by the cir- 

 cumscribed patches of bright green herbage. 



April 21th. 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. 

 This bird is known to have a wide geographical range, being 

 found on the west coast of South America, from the Strait of 

 Magellan along the Cordillera as far as eight degrees N. of the 

 equator. The steep cliff near the mouth of the Rio Negro is its 

 northern limit on the Patagonian coast ; and 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 at the head of Port Desire, the condor is not 

 uncommon ; yet only a few stragglers occasionally visit the sea- 

 coast. A line of cliff near the mouth of the Santa Cruz is fre- 

 quented by these birds, and about eighty miles up the river, 

 where the sides of the valley are formed by steep basaltic pre- 

 cipices, the condor reappears. From these facts, it seems that 

 the condors require perpendicular cliffs. In Chile, they haunt, 

 during the greater part of the year, the lower country near tlif 



