PERUVIAN REGIONS. 



151 



On the 17th> we started at 6i a.m., in a thick fog, which cleared in 

 little over an hour; when the sun proved oppressive for some dis- 

 tance up the valley, as had been predicted. Proceeding over a moun- 

 tain-ridge, at the end of " five leagues," we reached a third river, 

 and soon afterwards entered the hamlet of Yanga. We kept on the 

 Southern bank of the river for " five leagues" further, very gradually 

 and regularly ascending, and stopped for the night at the hamlet of 

 Yaso. 



The Desert-region extends to Yaso, and about two leagues beyond ; 

 being in this part of Peru not more than fifty geographical miles wide. 

 The rivers, receiving no accession of water after leaving the Andes, 

 traverse the Desert-region in widely-separated, continuous, long, and 

 very deep mountain-valleys. The one we followed, seldom afforded 

 room for irrigation ; but the river-bed was in many places wide, from 

 the water flowing in several channels. Many of the plants abound- 

 ing nearer the coast had given place to species that were now first 

 met with : as Schinus molle, the prevailing shrub along and upon the 

 exposed portions of the river-bed, and another frequent shrub, grow- 

 ing in company, a rose-leaved Bignonia, bearing yellow flowers : the 

 canebrakes continued, but unexpectedly consisted of a second species 

 of Pliragmites? ; agreeing at least in the leaves and habit, though not 

 less than twenty-five feet high : and in many places, the canebrakes 

 and other vegetable growth were abundantly mantled with a species 

 of Clematis. 



The Desert Upland. The infiltrated ground, even as artificially 

 enlarged, is only here and there interspersed, and occupies but a small 

 part of the area of Lower Peru; the remainder constitutes the Desert, 



My first near view of the Desert was obtained from Lima ; and on 

 proceeding towards a mountain-ridge, I found the soil loose, powdery, 

 and in every direction bare ; and for some time, could discover no 

 traces of vegetation. My attention was soon attracted to certain 

 greyish patches on the distant mountain-summits, supposed at first 

 to be some change in the mineral constituents of the soil ; on ascend- 

 ing to the nearest one, it proved a bed of intermingled TilJandsias and 

 Lichens. Having never heard of ground Tillandsias, I was the more 

 surprised at the strange companionship ; the Peruvian drizzle nourish- 

 ing these grey tribes, but not supplying sufficient moisture for a 

 continuous coating of green herbage. On closer examination, the 

 Tillandsias appeared to have originated on rocks ; but tufts falling 



