Elisée RECLUS, Géographie Universelle, t, XVIII, p

2. «I have followed them for days together and have seen them winding amidst the projections of hills, Curving in and out as topography required; here sustained by high walls of masoury, there cut into the living rock and in some cases COnducted in tunnels, through sharp spurs of the obstructing mountains. Occasionally, they were carried over narrow valleys or depressions in the grouyd on embankments fifty or sixty feet high; but Renerally they were deflected arou:;d opposing obstacles, on an easy and uniform descending grade.» SQUIER, Peru, p. 218, ee