the bottom of the cañon, and where it occasionally spreads out into a valley of minute dimensions, are the remains of towns and cities, whose origin is hidden in the mists of fable, and whose history is unknown. This region bears no resemblance to any other picture of nature--lifted above the rest of the world, as coldly and calmly silent, as impenetrable, as the arctic stars. Here was developed a civilization which left memorials of its advancement, genius, and industry carved in massive stone, and written upon the everlasting hills in symbols which even the earthquakes have been unable to erase. Here are the ruins of cities which were more populous than any that have existed in Peru since--evidences of industry which their destroyers were too indolent to imitate, and of a skill which could cope with everything but the destructive weapons of the invaders. A survey of their remains justifies the estimates given of their enormous population, which are that the people once herded in these narrow valleys were as numerous as those now spread over the United States. The struggle which they had to sustain themselves is shown in the traces of their industry and patience. They built their dwellings upon rocks, and buried their dead in caves, in order to utilize what soil there was for agriculture. They excavated great areas in the desert until they reached moisture enough for vegetation, and then brought guano from the islands of the sea to fill these sunken gardens. They terraced every hill and mountain side, and placed soil in the crevices of the rocks, until not an inch of surface that could grow a stalk of maize was left unproductive. The steep mountains along the Rimac are terraced up to the very summit, these terraces being often as narrow as the steps of a stairway, and many of them are walled up with stone. They are veritable hanging-gardens, and lie on such slopes that they look as if it were impossible for any one to get foothold to cultivate them, or even for the roots of what was planted there to sustain the mighty winds which sometimes sweep down the valley. [Illustration: A BIT OF INCA ARCHITECTURE.] The irrigation system of the Incas was perfect, their ditches extending for hundreds of miles, and curving around the hills, here sustained by high walls of masonry, and there cut through the living rock. They were carried over narrow valleys upon enormous embankments, and show evidence of engineering skill as great as that which lifted the Meiggs railroad above [Illustration: RELIC OF A PAST CIVILIZATION.]