In the morning of May 17th I left Sandia on my own trusty mule, driving two others with the plants before me, and accompanied by their owner on foot, an Indian named Angelino Paco, a middle-aged respectable-looking man, who had been one of the Alcaldes of Sandia in 1859. Mr. Weir started for Arequipa on the same day, by way of Crucero. Passing through Cuyo-cuyo without stopping, I continued to ascend a mountain-gorge, by the side of the stream, but Paco had never been out of the valley of Sandia before, and was useless as a guide. All along the banks of the stream there were square pools dammed up and filled with heaps of potatoes and ocas, placed there to freeze into _chuñus_, the principal food of the Indians when in the forests, or on the coffee or coca estates. Higher up the gorge all signs of habitation cease, though there are still abandoned tiers of ancient terraces, and the mountain scenery is quite magnificent. Night coming on without a moon, I halted under a splendid range of frowning black cliffs, and succeeded in pitching the tent in the dark, but there was no fuel, and on opening the leathern bag I found that my little stock of food and lucifer-matches had been stolen in Sandia. I was thus entirely dependent for existence on Paco's parched maize, which proved uncommonly hard fare. The cold was intense during the night, and penetrated through the tent and clothes to the very marrow. At daybreak Paco and I loaded the mules, and continued to ascend the gorge by the side of the river of Sandia, which becomes a noisy little rill, and finally falls, as a thin silvery cascade, over a black cliff. Reaching the summit of the snowy cordillera of Caravaya, we commenced the journey over lofty grass-covered plains, where the ground was covered with stiff white frost. There were flocks of vicuñas on the plain, and _huallatas_, large white geese with brown wings and red legs, on the banks of the streams; but as we advanced even these signs of life ceased, and, when night closed in, I looked round on the desolate scene, and thought that to make a direct cut across the cordilleras to Vilque by compass-course was a very disagreeable way of travelling, though, in this case, a necessary one. I had been eleven hours in the saddle, when Paco found an abandoned shepherd's hut, built of loose stones, three feet high, and thatched with _ychu_ grass. The minimum thermometer, during the night, was as low as 20° Fahr. by my side.