356 NORTHERN CHILE. [cHap. xvI. 
rain falls on the mud-bank, when left dry, it deepens the already- 
formed shallow lines of excavation; and so is it with the rain 
of successive centuries on the bank of rock and soil, which we 
call a continent. 
We rode on after it was dark, till we reached a side ravine 
with a small well, called “‘ Agua amarga.” The water deserved 
its name, for besides being saline it was most offensively putrid 
and bitter; so that we could not force ourselves to drink either 
tea or maté. I suppose the distance from the river of Copiapd 
to this spot was at least twenty-five or thirty English miles ; in the 
whole space there was not a single drop of water, the country de- 
serving the name of desert in the strictest sense. Yet about 
halfway we passed some old Indian ruins near Punta Gorda: I 
noticed also in front of some of the valleys, which branch off 
from the Despoblado, two piles of stones placed a little way 
apart, and directed so as to point up the mouths of these small 
valleys. My companions knew nothing about them, and only 
answered my queries by their imperturbable “ quien sabe?” 
I observed Indian ruins in several parts of the Cordillera: 
the most perfect, which I saw, were the Ruinas de Tambillos, 
in the Uspallata Pass. Small square rooms were there huddled 
together in separate groups: some of the doorways were yet 
standing; they were formed by a cross slab of stone only about 
three feet high. Ulloa has remarked on the lowness of the doors 
in the ancient Peruvian dwellings. These houses, when per- 
fect, must have been capable of containing a considerable num- 
ber of persons. Tradition says, that they were used as halt- 
ing places for the Incas, when they crossed the mountains. 
Traces of Indian habitations have been discovered in many other 
parts, where it does not appear probable that they were used as 
mere resting-places, but yet where the land is as utterly unfit for 
any kind of cultivation as it is near the Tambillos or at the Incas 
Bridge, or in the Portillo Pass, at all which places I saw ruins. 
In the ravine of Jajuel, near Aconcagua, where there is no pass, 
I heard of remains of houses situated at a great height, where 
it is extremely cold and sterile. At first I imagined that these 
buildings had been places of refuge, built by the Indians on the 
first arrival of the Spaniards; but I have since been inclined 
to speculate on the probability of a small change of climate, 
