It remains to consider the special topographic features of the mountain environments we are discussing, in the Vilcapampa region on the eastern border of the Andes ([Fig. 36]). The Cordillera Vilcapampa is snow-crested, containing a number of fine white peaks like Salcantay, Soray, and Soiroccocha ([Fig. 140]). There are many small glaciers and a few that are several miles long. There was here in glacial times a much larger system of glaciers, which lived long enough to work great changes in the topography. The floors of the glaciated valleys were smoothed and broadened and their gradients flattened (Figs. 137 and 190). The side walls were steepened and precipitous cirques were formed at the valley heads. Also, there were built across the valleys a number of stony morainic ridges. With all these changes there was, however, but little effect upon the main masses of the big intervalley spurs. They remain as before—bold, wind-swept, broken, and nearly inaccessible.
Fig. 36—Regional diagram for the Eastern Cordillera or Cordillera Vilcapampa. Note the crowded zones on the right (east and north) in contrast to the open succession on the left. In sheltered places woodland extends even higher than shown. At several points patches of it grow right under the snowline. Other patches grow on the floors of the glaciated valley troughs.
The work of the glaciers aids the mountain people. The stony moraines afford them handy sizable building material for their stone huts and their numerous corrals. The thick tufts of grass in the marshy spots in the overdeepened parts of the valleys furnish them with grass for their thatched roofs. And, most important of all, the flat valley floors have the best pasture in the whole mountain region. There is plenty of water. There is seclusion, and, if a fence be built from one valley wall to another as can be done with little labor, an entire section of the valley may be inclosed. A village like Choquetira, located on a bench on the valley side, commands an extensive view up and down the valley—an important feature in a grazing village where the corrals cannot always be built near the houses of the owners. Long, finger-like belts of highland-shepherd population have thus been extended into the mountain valleys. Sheep and llamas drift right up to the snowline.
There is, however, a marked difference between the people on opposite sides of the Cordillera Vilcapampa. On the west the mountains are bordered by a broad highland devoted to grazing. On the east there is a narrower grazing belt leading abruptly down to tropical valleys. The eastern or leeward side is also the warmer and wetter side of the Cordillera. The snowline is several hundred feet lower on the east. The result is that patches of scrub and even a little woodland occur almost at the snowline in favored places. Mist and storms are more frequent. The grass is longer and fresher. Vegetation in general is more abundant. The people make less of wool than of cattle, horses, and mules. Vilcabamba pueblo is famous for its horses, wiry, long-haired little beasts, as hardy as Shetland ponies. We found cattle grazing only five hundred feet below the limit of perpetual snow. There are cultivated spots only a little farther down, and only a thousand feet below the snow are abandoned terraces. At the same elevation are twisted quenigo trees, at least two hundred years old, as shown by their rings of growth. Thus the limits of agriculture are higher on the east; likewise the limits of cattle grazing that naturally goes with agriculture. Sheep would thrive, but llamas do better in drier country, and the shepherd must needs mix his flocks, for the wool which is his chief product requires transportation and only the cheap and acclimated llama is at the shepherd’s disposal. From these facts it will be seen that the anthropo-geographic contrasts between the eastern and western sides of the Cordillera Vilcapampa are as definite as the climatic and vegetal contrasts. This is especially well shown in the differences between dry Arma, deep-sunk in a glaciated valley west of the crest of the mountains, and wet Puquiura, a half-day’s journey east of the crest. There is no group on the east at all comparable to the shepherds of Choquetira, either in the matter of thorough-going dependence upon grazing or in that of dependence upon glacial topography.