As I have said, few traces of the Inca roads, such as are described by the early writers, and such as Humboldt saw in Northern Peru, are now to be found in the southern part of that country; and as the modern pathways must follow the ancient lines, I infer that they never existed here, for there is no reason why they should have suffered more from time and the elements in one part of the country than in another. Between Cuzco and the sweet valley of Yucay there are numerous traces of an ancient road, some sections of which are perfect. These sections coincide in character with the long reaches in the direction of Quito. They consist of a pathway from ten to twelve feet wide, raised slightly in the centre, paved with stones, and the edges defined by larger stones sunk firmly in the ground. Where this road descends from the elevated _puna_--a sheer descent of almost four thousand feet into the valley of Yucay--it zigzags on a narrow shelf cut in the face of the declivity, and supported here and there, where foothold could not otherwise be obtained, by high retaining-walls of cut stone, looking as perfect and firm as when first built centuries ago. High mountain-ranges and broad and frigid deserts, swept by fierce, cold winds, are not the sole obstacles to intercommunication in the Altos of Peru, and among those snow-crowned monarchs of the Andes and Cordilleras. There are deep valleys, gorges, and ravines among the mountains, or cut deep in the plains that alternate with them, in which flow swelling rivers or rapid torrents, fed by the melting snows in the dry season, and swollen by the rains in the wet season. They are often unfordable, but still they must somehow be passed by the traveller. A few bridges of stone were constructed by the Spaniards, some after the Conquest, and a few others have been erected by their descendants; but, as a rule, the rivers and mountain-torrents are passed to-day by the aid of devices the same as were resorted to by the Incas, and at points which they selected.