THE BORDER VALLEYS OF THE EASTERN ANDES 



81 



turn in the valley giving freer access to the up-valley winds that 

 sweep through the pass at Pongo de Mainique. 



Northward from Abra Tocate (Fig. 55) the forest is prac- 

 tically continuous. The break between the two vegetal regions 

 is emphasized by a corral for cattle and mules, the last 

 outpost of the plateau 

 herdsmen. Not three 

 miles away, on the oppo- 

 site forested slope of the 

 valley, is the first of the 

 Indian clearings where 

 several families of Machi- 

 gangas spend the wet sea- 

 son when the lower river 

 is in flood (Fig. 21). The 

 grass lands will not yield 

 corn and coca because the 

 soil is too thin, infertile, 

 and dry. The Indian 

 farms are therefore all in 

 the forest and begin al- 

 most at its very edge. 

 Here finally terminates a 

 long peninsula of grass- 

 covered country. Below this point the heat and humidity rapidly 

 increase; the rains are heavier and more frequent; the country 

 becomes almost uninhabitable for stock; transportation rates 

 double. Here is the undisputed realm of the forest with new kinds 

 of trees and products and a distinctive type of forest-dwelling 

 Indian. 



At the next low pass is the skull of an Italian who had mur- 

 dered his companions and stolen a season's picking of rubber, at- 

 tempting to escape by canoe to the lower Urubamba from the 

 Pongo de Mainique. The Machigangas overtook him in their 

 swiftest dugouts, spent a night with him, and the next morning 

 shot him in the back and returned with their rightful property — 



Fig. 55 — Map to show the relation of the 

 grasslands of the dry lower portion of the 

 Urubamba Valley (unshaded) to the forested 

 lands at higher elevations (shaded). See Fig. 

 54 for climatic conditions. Patches and slender 

 tongues of woodland occur below the main 

 timber line and patches of grassland above it. 



