260 THE VOYAGE. ^TAT. 26. [1835. 



work. The scenery was so new, and so majestic ; every- 

 thing at an elevation of 12,000 feet bears so different an aspect 

 from that in a lower country. I have seen many views more 

 beautiful, but none with so strongly marked a character. 

 To a geologist, also, there are such manifest proofs of 

 excessive violence ; the strata of the highest pinnacles are 

 tossed about like the crust of a broken pie. 



I crossed by the Portillo Pass, which at this time of the 

 year is apt to be dangerous, so could not afford to delay 

 there. After staying a day in the stupid town of Mendoza, I 

 began my return by Uspallate, which I did very leisurely. 

 My whole trip only took up twenty-two days. I travelled 

 with, for me, uncommon comfort, as I carried a bed! My 

 party consisted of two Peons and ten mules, two of which 

 were with baggage, or rather food, in case of being snowed up. 

 Everything, however, favoured me ; not even a speck of this 

 year's snow had fallen on the road. I do not suppose any 

 of you can be much interested in geological details, but I 

 will just mention my principal results : Besides under- 

 standing to a certain extent the description and manner of 

 the force which has elevated this great line of mountains, 

 I can clearly demonstrate that one part of the double line 

 is of an age long posterior to the other. In the more ancient 

 line, which is the true chain of the Andes, I can describe the 

 sort and order of the rocks which compose it. These are 

 chiefly remarkable by containing a bed of gypsum nearly 

 2000 feet thick a quantity of this substance I should think 

 unparalleled in the world. What is of much greater con- 

 sequence, I have procured fossil shells (from an elevation of 

 12,000 feet). I think an examination of these will give an 

 approximate age to these mountains, as compared to the 

 strata of Europe. In the other line of the Cordilleras there 

 is a strong presumption (in my own mind, conviction) that 

 the enormous mass of mountains, the peaks of which rise to 

 13,000 and 14,000 feet, are so very modern as to be con- 



