destroyed them; and this still more towards the sea-coast, (for the sake of obtaining fine cut stones for new buildings; and where the want of water consequent on the destruction of the aqueducts has rendered the soil barren), than on the ridges of the Andes, or in the deep-cleft valleys by which the mountain chain is intersected. In the long day's journey from the syenitic rocks of Zaulaca to the Valley of San Felipe (rich in fossils, and situated at the foot of the icy Paramo de Yamoca), we were obliged to wade through the Rio de Guancabamba (which flows into the Amazons), no less than twenty-seven times, on account of the windings of the stream; while we continually saw near us, running in a straight line along the side of a steep precipice, the remains of the high built road of the Incas with its Tambos. The mountain torrent, though only from 120 to 150 English feet broad, was so strong and rapid that, in fording it, our heavily laden mules were often in danger of being swept away by the flood. They carried our manuscripts, our dried plants, and all that we had been collecting for a year past. Under such circumstances one watches from the other side of the stream with very anxious suspense until the long train of eighteen or twenty beasts of burden have passed in safety.
The same Rio de Guancabamba, in the lower part of its course, where it has many falls and rapids, is made to serve in a very singular manner for the conveyance of correspondence with the coast of the Pacific. In order to expedite more quickly the few letters from Truxillo which are intended for the province of Jaen de Bracamoros, a "swimming
