206 



DISTRIBUTION OF PLANTS. 



interrupted by ice ; so slightly as to have escaped notice, but from being 

 all the ice we met with on the Peruvian Andes. From the crest, we 

 descended Westward by the Chancay Valley to Baiios, as already 

 mentioned. 



After a day at Bafios, we reascended on the 23d into the alpine 

 region, and returned to Casa-Cancha ; arriving there in time for a 

 short botanical excursion up the neighboring hills. 



On the 24th, we turned homewards, following the Canta route. 

 Before reaching the crest of the Andes, I went part way up a 

 detached mountain-peak, conspicuous from the uninterrupted hori- 

 zontal margin of its cap of snow. On approaching this snow-line, 

 the ground was found to be frozen, and at first seemed devoid of 

 vegetation ; after some searching, solitary short blades of grass were 

 discovered here and there, and were extricated with difficulty ; higher 

 up, even these had disappeared from the bare spots amid the snow ; 

 which last extended everywhere in a thin coating, but compact and 

 hardened. Even at this great elevation, I was unable to obtain an 

 extended view of the Andes; but several grand snowy peaks were in 

 sight, some of them projecting full three thousand feet above the con- 

 tinuous crest. The ground I was standing on had been the bottom 

 of the sea, as was shown by fossil remains of marine animals. Pick- 

 ing up the Ammonite, already mentioned, I returned to the travelled 

 path ; joined Mr. Brackenridge, and after descending further to the 

 margin of one of the lakes, we continued on foot across the remainder 

 of the alpine district. 



Climate. Some general idea of the climate may be gathered from 

 what has been already stated. Amid perpetually recurring frosts and 

 snows, the dreariness equalling or exceeding that of Terra del Fuego, 

 there is yet no distinction of seasons. Whether rain ever falls, we 

 did not ascertain ; but the ground in the daytime was always moist, 

 from the melting of frost and snow. The following Observations of 

 the temperature were taken by ourselves : 



May 19th, on the crest of the Andes; the lowest temperature during the afternoon, 50° Fahr. 

 " 20th, at Casa-Cancha; at 3 p.m., the environs covered with snow, . . 45° " 

 " " " after nightfall (the snow having disappeared), . 42° " 



" 21st, " within doors, at sunrise (a heavy frost outside), . 36° " 



" 23d, " within doors, in the afternoon, .... 44° " 



" 24th, " within doors, at 6^ A.M., 36° " 



" " at the highest point on the crest of the Andes, near the snow limit, 46° " 



