CHAPTEE II 



THE RAPIDS AND CANYONS OF THE URUBAMBA 



Among the scientifically unexplored regions of Peru there is 

 no other so alluring to the geographer as the vast forested realm 

 on the eastern border of the Andes. Thus it happened that within 

 two weeks of our arrival at Cuzco we followed the northern trail 

 to the great canyon of the Urubamba (Fig. 8), the gateway to the 

 eastern valleys and the lowland plains of the Amazon. It is here 

 that the adventurous river, reenforced by hundreds of mountain- 

 born tributaries, finally cuts its defiant way through the last of its 

 great topographic barriers. More than seventy rapids interrupt 

 its course; one of them, at the mouth of the Sirialo, is at least a 

 half-mile in length, and long before one reaches its head he hears 

 its roaring from beyond the forest-clad mountain spurs. 



The great bend of the Urubamba in which the line of rapids 

 occurs is one of the most curious hydrographic features in Peru. 

 The river suddenly changes its general northward course and 

 striking south of west flows nearly fifty miles toward the axis of 

 the mountains, where, turning almost in a complete circle, it makes 

 a final assault upon the eastern mountain ranges. Fifty miles 

 farther on it breaks through the long sharp-crested chain of the 

 Front Range of the Andes in a splendid gorge more than a half- 

 mile deep, the famous Pongo de Mainique (Fig. 9). 



Our chief object in descending the line of rapids was to study 

 the canyon of the Urubamba below Rosalina and to make a topo- 

 graphic sketch map of it. We also wished to know what secrets 

 might be gathered in this hitherto unexplored stretch of country, 

 what people dwelt along its banks, and if the vague tales of de- 

 serted towns and fugitive tribes had any basis in fact. 



We could gather almost no information as to the nature of the 

 river except from the report of Major Kerbey, an American, who, 

 in 1897, descended the last twenty miles of the one hundred we 

 proposed to navigate. He pronounced the journey more hazard- 



8 



