THE PERUVIAN LANDSCAPE 187 



We shall now turn to each group of features for description 

 and explanation, selecting for first consideration the forms of 

 widest development and greatest significance — the high-level ma- 

 ture slopes lying between the lofty mountains which rise above 

 them and the deep, steep-walled valleys sunk far below them. 

 These are the great pasture lands of the Cordillera; their higher 

 portions constitute the typical puna of the Indian shepherds. In 

 many sections it is possible to pasture the vagrant flocks almost 

 anywhere upon the graded slopes, confident that the ichu, a 

 tufted forage grass, will not fail and that scattered brooks and 

 springs will supply the necessary water. At nightfall the flocks 

 are driven down between the sheltering walls of a canyon or in 

 the lee of a cliff near the base of a mountain, or, failing to reach 

 either of these camps, the shepherd confines his charge within the 

 stone walls of an isolated corral. 



In those places where the graded soil-covered slopes lie within 

 the zone of agriculture — below 14,000 feet — they are cultivated, 

 and if the soil be deep and fertile they are very intensively culti- 

 vated. Between Anta and Urubamba, a day's march north of 

 Cuzco, the hill slopes are covered with wheat and barley fields 

 which extend right up to the summits (Fig. 134). In contrast are 

 the uncultivated soil-less slopes of the mountains and the bare val- 

 ley walls of the deeply intrenched streams. The distribution of 

 the fields thus brings out strongly the principal topographic rela- 

 tions. "Where the softer slopes are at too high a level, the climatic 

 conditions are extreme and man is confined to the valley floors 

 and lower slopes where a laborious system of terracing is the first 

 requirement of agriculture. 



The appearance of the country after the mature slopes had 

 been formed is brought out in Fig. 122. The camera is placed on 

 the floor of a still undissected, mature valley which shows in the 

 foreground of the photograph. In the middle distance is a valley 

 whose great depth and steepness are purposely hidden; beyond 

 the valley are the smoothly graded, catenary curves, and inter- 

 locking spurs of the mature upland. In imagination one sees the 

 valleys filled and the valley slopes confluent on the former (now 



