I 



216 PATAGONIA. Aprils 1834. 



five hundred. The puma with the condor in its train, follows 

 and preys upon these animals. The footsteps of the former 

 were to be seen almost every where on the banks of the river ; 

 and the remains of several guanaco, with their necks dislo- 

 cated, and bones broken, showed how they had met their 

 death. 



April 24th. — Like the navigators of old when approach- 

 ing an unknown land, we examined and watched for the most 

 trivial sign of a change. The drifted trunk of a tree, or a 

 boulder of primitive rock, was hailed with joy, as if we had 

 seen a forest growing on the flanks of the Cordillera. The 

 top, however, of a heavy bank of clouds, which remained 

 almost constantly in one position, was the most promising 

 sign, and eventually turned out true. At first the clouds 

 were mistaken for the mountains themselves, instead of the 

 masses of vapour condensed by their icy summits. 



26th. — We this day met with a marked change in the 

 geological structure of the plains. From the first starting I 

 had carefully examined the gravel in the river, and for 

 the two last days had noticed the presence of a few small 

 pebbles of a very cellular basalt. These gradually increased 

 in number and in size, but none equalled in dimensions a 

 man^s head. This morning, however, pebbles of the same 

 rock, but more compact, suddenly became abundant, and in 

 the course of half an hour, we saw at the distance of five or 

 six miles the angular edge of a great basaltic platform. 

 When we arrived at its base we found the stream bubbling 

 among the fallen blocks. For the next twenty-eight miles, 

 the river-course was encumbered with these basaltic masses. 

 Above that limit, immense fragments belonging to a primi- 

 tive formation, but derived from the surrounding alluvium, 

 were equally numerous. In both cases no fragments at all 

 remarkable in size or number had been washed down the 

 stream, more than three or four miles below either the 

 parent rock, or the mass of alluvium from which they were 

 derived. Considering the singular rapidity of the great body 

 of water in the St. Cruz, and that no still reaches occur in 



