The country between La Paz and Oruro is very similar to that we had crossed coming from Guaqui. There are the same vistas of barren plains, green fields, llamas, and asses on the slopes, and dazzling snow-fields in the background. The plateau is strewn with marine fossils, mostly _trilobites_, reminders of the days when Lake Titicaca was many times its present size. We covered the one hundred and twenty-seven miles to Oruro in six hours, and spent the night there. This city owes its existence to the many mines located near by--some within the city’s limits--and to the wealth they yield in tin, silver, and other metals. Next morning the journey was continued toward Cochabamba. Shortly before noon the level country was left behind and we started down the eastern slope of a ridge that leads into the lower country. This part of the road-bed is new; the greater part of it is laid on a narrow shelf of rock carved and blasted out of the mountainside. Perpendicular walls of granite tower above to a height of hundreds of feet on one side; in places the top of the huge masses seems to hang over the track in a tottering position and one expects the rumble of the train to set it in motion and bring an avalanche of destruction down upon one’s head. A small stream flows through the bottom of the gorge. During the greater part of the year it is a mere rivulet that trickles harmlessly over the shallow, pebbly bottom of its course; but when the torrential rains of winter fall it rises rapidly to the proportions of a mighty river and sweeps away sections of the railroad. Long rows of breakwater have been placed alongside the base of the road-bed to protect it from the ravages of the flood; they consist of loaf-shaped piles of stone bound together with wire netting; these would be effective against the water alone, but they cannot resist the demolishing force of the huge boulders that are rolled down from the mountains by the strong current. A number of breaks in the line had been made by landslides just before our visit, so the train could not proceed beyond Changollo, a settlement of half a dozen Quechua Indian huts and a good-sized station, the elevation of which is ten thousand feet. We were met by a representative of the railway company and given quarters in the station buildings; the other passengers immediately engaged mules and llamas and started for Cochabamba. The reason for our delay was that we had just received a shipment of ammunition and supplies from New York, and some time would be required to repack them in parcels of equal weight suitable for transportation by pack-train.