320 USPALLATA PASS. [CHAP. xv. 



the highest crest. The valley and the huge rocky mountains are 

 extremely barren : during the two previous nights the poor mules 

 had absolutely nothing to eat, for excepting a few low resinous 

 bushes, scarcely a plant can be seen. In the course of this clay we 

 crossed some of the worst passes in the Cordillera, but their danger 

 has been much exaggerated. I was told that if I attempted to 

 pass on foot, my head would turn giddy, and that there was no 

 room to dismount ; but I did not see a place where any one might 

 not have walked over backwards, or got oif his mule on either side. 

 One of the bad passes, called las Animas (the Souls), I had crossed, 

 and did not find out till a day afterwards, that it was one of the 

 awful dangers. No doubt there are many parts in which, if the 

 mule should stumble, the rider would be hurled down a great 

 precipice; but of this there is little chance. I dare say, in the 

 spring, the " laderas," or roads, which each year are formed anew 

 across the piles of fallen detritus, are very bad ; but from what I 

 saw, I suspect the real danger is nothing. With cargo-mules the 

 case is rather different, for the loads project so far, that the animals, 

 occasionally running against each other, or against a point of rock, 

 lose their balance, and are thrown down the precipices. In cross- 

 ing the rivers I can well believe that the difficulty may be very 

 great : at this season there was little trouble, but in the summer 

 they must be very hazardous. I can quite imagine, as Sir F. Head 

 describes, the different expressions of those who have passed the 

 gulf, and those who are passing. I never heard of any man being 

 drowned, but with loaded mules it frequently happens. The 

 arriero tells you to show your mule the best line, and then allow 

 her to cross as she likes : the cargo-mule takes a bad line, and is 

 often lost. 



April Uh. From the Eio de las Vacas to the Puente del Incas, 

 half a day's journey. As there was pasture for the mules, and 

 geology for me, we bivouacked here for the night. When one hears 

 of a natural Bridge, one pictures to one's self some deep and 

 narrow ravine, across which a bold mass of rock has fallen ; or a 

 great arch hollowed out like the vault of a cavern. Instead of 

 this, the Incas Bridge consists of a crust of stratified shingle, 

 cemented together by the deposits of the neighbouring hot springs. 

 It appears, as if the stream had scooped out a channel on one side, 

 leaving an overhanging ledge, which was met by earth and stones 

 falling down from the opposite cliff. Certainly an oblique junction, 



