36 THE RUBBER INDUSTRY 



time and trouble in the transport of merchandise and 

 rubber to and from passing vessels. There is, indeed, 

 very little outstanding evidence in this section of the 

 great wealth extracted from these regions during the past 

 decade ; and should low prices lead to the abandonment 

 of the properties for a year or two, all proofs of civiliza- 

 tion would disappear, and the greater part of the country 

 revert to its pristine state of jungle and impenetrable 

 undergrowth. 



Access to the territories comprised in the third sec- 

 tion of the Amazon Valley is made difficult by the pres- 

 ence of a rocky ledge which exists for some thousands 

 of miles, outcropping to the east of the River Tocantins, 

 and following the contour of the foot-hills of the Andes 

 in a north-westerly direction for a distance of some 

 2,500 miles. This ledge is the cause of the cataracts 

 and rapids dividing the upper and lower rivers of the 

 southern and western areas ; it passes through the 

 State of Matto Grosso, crossing the Rivers Tocantins, 

 Xingu, and Tapajoz, thence to the vicinity of Porto 

 Velho on the Madeira; it continues to Cachoeira on 

 the Purus and Sao Felipe on the Jurua; and finally 

 it reaches the Ucayale, to the south-west of Iquitos. 

 The cataracts formed by this outcrop of rocky stratifi- 

 cation are a serious impediment to navigation ; the fact 

 that in the dry season they restrict all communication 

 except by flat-bottomed vessels of very shallow 

 draught, and that when the river is unusually low 

 even these cannot pass the rapids, adds materially to 

 the difficulties of working on the rubber properties. 

 They increase the cost of transport for both inward 

 and outward freight, and necessitate a heavy capital 



