Lardner Gibbon, Lieutenant, U.S.N., Exploration of the Valley of the Amazon… (1854)
“ The water from the mountains passes down the ravine to small patches of sugar-cane. The mountains are wild; winding around one of them, we suddenly came in sight of the long-looked for river Apurimac. Its waters foam as they dash over its rocky bed. Our view was cut off by another turn, and leaving the surface of the earth, we enter a tunnel, cut into the mountain, which stands like its strata, perpendicular, by the side of the river. Sky-light holes are cut through the rock, and as we travel along, in alternate light and darkness, the arrieros shout at the top of their voices at the train. ”
