174 Copper Mines of Chili. (April, 
the plain of Algaroval towards the sea. The water flows in 
good sized streams into the eastern edge of that plain from 
the Andes, but is soon lost in the sand. In its long passage 
through miles of soil it becomes saturated with soluble 
mineral matters, and among others with salts of lime, 
which in the Canta del Agua form thin beds of limestone of 
great purity. The strata of soil in the Canta del Agua 
are :— 
1 yard of loose sand, pebbles, and salt. 
ree of sand, alternating with thin layers of carbonate 
2 ya of lime, which on removal rapidly reform. 
Sand and clay. 
Old river bed—a compact mass of shale and 
boulders of undetermined thickness, imper- 
meable to water, and on which it flows. 
Following the Canta del Agua into the Plain of Algaroval, 
and across it in a south-east direction, the railroad runs 
to Yirba Buena, 71 miles from Canta del Agua, and 
gg from Carrizal Bajo on the Pacific. This station is 
at the foot of the spur of the Andes, where occurs the argen- 
tiferous copper lode of Corro Blanco. The lodes yielded at 
surface antimoniate of copper rich in silver; this changed 
at about 30 fathoms to argentiferous copper glance and 
galena, and the grey copper was replaced by copper pyrites, 
which is now the prominent product, though small quan- 
tities of the other ores are still exploited. The principal 
mines have been yielding largely and profitably for some 
years. Beside the principal lodes at Carrizal and Cerro 
Blanco, there are innumerable others worked on a small 
scale by two or more poor miners, the yield from all of 
which combined is considerable. 
The next copper deposits worthy of note lie between 
Copiap6é and Nantoko, in the hills bordering the river of 
CopiapO. They are exceedingly numerous and yield rich 
oxidised ores; but none of the mines are worked in the 
same systematic manner as those of Tomaya and Carrizal, 
nor do any of them promise to rise into great importance. 
On the contrary, partly from the unskilful way in which 
they have been worked, and partly from the high percentage 
required by the smelter (18 per cent), which no mine can 
continue to give after the rich outcrop has been removed, 
unless water dressing is possible, the yield of the Copiapo 
copper mines must continue to fall off. 
Not so, however, that of the great mines back of the port 
of Chanaral, in the desert of Atacama. From Chanaral de 
