and water. These immense groups of mountains are traversed by rugged defiles, and narrow paths, the result of volcanic action, wind along the edges of precipices, while below roar the mountain streams carrying great rocks along with them, tossing them about as though they were straws. Here nature displays her giant strength as an artificer, decking herself with no other ornaments than the cactus, mosses, and thorny plants; everywhere are seen traces of the world in embryo, as it emerged from chaos in the process of creation.
Between the Cordillera and the coast range stretches a great central valley, cut across in places by spurs from the higher mountains, which take an oblique line to the south till they lose themselves in the ocean, or reappear as solitary islands or as clusters of islands, which are the summits of mountains springing from the bed of the sea.
The great Cordillera can only be crossed at certain passes. Those which have connection with our history are: in the centre, those of Uspallata and Los Patos, in front of Mendoza and San Juan; to the north, those of La Ramada and Come-Caballos, by which the Argentine province of La Rioja communicates with Coquimbo and Copiapó; and to the south, that of the Planchon, which gives access to the valley of Talca, and that of the Portillo which leads to the plain of Maipó and to the capital of Chile. These passes, from 9,000 feet to 12,000 feet above the level of the sea, are covered with snow in winter, and are practicable only in the height of summer. Until then they had been crossed only by small detachments of soldiery, or by troops of mules, the paths being in many places so narrow as only to give room for one mounted man at a time. The passage of a numerous army with guns and baggage was held to be impossible and had never been thought of till the feat was accomplished by San Martin. Food and forage for men, mules, and horses had to be carried with them, and it was necessary to reach the other side in force sufficient to overcome a watchful
