192 S. CRUZ, PATAGONIA chap. 



supposition would have been quite inadmissible ; because, the 

 same step-Hke plains with existing sea-shells lying on their 

 surface, which front the long line of the Patagonian coast, sweep 

 up on each side of the valley of Santa Cruz. No possible 

 action of any flood could thus have modelled the land, either 

 within the valley or along the open coast ; and by the formation 

 of such step-like plains or 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 that 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 basaltic lava. Nevertheless, we must believe that the 

 strata undermined by the waters of this ancient strait were 

 broken up into huge fragments, and these lying scattered on the 

 beach were reduced first to smaller blocks, then to pebbles, and 

 lastly to the most impalpable 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 ram- 

 bling up some of the narrow and rocky defiles, I could almost 

 have fancied myself transported back again to the barren 

 valleys of 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 circumscribed patches of bright green 

 herbage. 



April 2'jth. — The bed of the river became rather narrower, 

 and hence the stream more rapid. It here ran at the rat€ ot 

 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 



