180 
very fair specimen of Peruvian barrenness, of which it is 
hardly possible to form an idea without witnessing it. I have 
already alluded to the desert appearance of the coast, where 
you may travel whole days, over pure sand, without any trace 
of vegetation; or, if the road lies occasionally near a range 
of mountains, the scene is only varied by masses of bare 
rock, of which the fragments that cover the road are as fresh 
and unsoiled as if they had fallen but yesterday from the 
hammer of a mason. Of the latter description is Rio Seco, 
except in a few spots, where nature, as if to vindicate her 
power even in a desert, has scattered some patches of Til- 
landsie, and these exiles from the vegetable world flourish 
in spite of the arid atmosphere and burning sun. One 
species, the 7. purpurea, was in full flower when we passed. 
As the day advanced, we found the heat excessive, having 
now exchanged the hazy atmosphere of the coast for the 
clear deep blue sky of a tropical mountain region. At the 
head of the Rio Seco, the road winds up a steep hill, from the 
summit of which, the green valley is seen at a distance of 
two leagues, tantalizing the thirsty traveller during the two 
hours that his mule takes to crawl over the rough stony 
bottom of the ravine that leads to it. The Tillandsie are 
here replaced by a few Melocacti, and one or two solitary 
plants of Cactus tetragonus. 
We regained the main valley about three o'clock, at 8 
place called Yangas, consisting only of half a dozen houses, 
immediately beyond which is the village of Alcocota, five 
leagues from Cavallero, by the road we came; by the valley 
sad is six leagues and a half. The valley, where we turned off, 
. Às nearly a league in breadth, but here it had contracted to 
about a mile, and the hills that bound it are high and steep 
especially on the north side, where the rock forms a perpen- 
„ dicular wall, Greenstone is the prevailing rock all the way 
from Limato this place; between the city and Arnipuquio, it is 
partially covered with stratified limestone and slate-clay, and 
Tierm leading to Alcocota, by coarse argillaceous 
. Alcocota is considered the boundary of the rainy district 
