412 



AMAZONIA AND LA PLATA. 



gradually brouglit about a chronic state of fierce warfare, in vviiich no quarter 

 was given on either side. When a camp or a village was surprised, all 

 the men were slaughtered, at times even tortured, the women being reserved 

 as slaves or concubines, the children either killed or kept as thralls about the 

 farmsteads. 



To protect the outlying settlements from these incursions, it was found neces- 

 sary to lay down various frontier lines at different periods, and to defend them 

 with forts and earthworks. At the close of the eighteenth century the limit of the 

 area of colonisation was indicated south of Buenos Ayres by the Rio Salado Valley, 

 and extended westwards about the thirty -fourth parallel as far as San Rafael at 

 the foot of the Andes. But the Indians took advantage of the War of Indepen- 



Fig. 164. — Lines of Otjtposts against the Indians. 

 Scale 1 : 17,000,000. 



310 Miles. 



dence to break through this cordon. In 18'3-3, however, ihey were driven south of 

 the Rio Negro into Patagonia proper, and several of the tribes asked for peace. 

 Then the civil wars gave the natives a fresh respite, and even enabled them to 

 renew their incursions as allies of one or other of the factions. Thus they several 

 times occupied the city of San Luis, and blocked the main route between Chili, 

 Mendoza, and Buenos Ayres. 



On the restoration of peace the Indians, steadily diminishing in numbers, were 

 again driven back, and then the fortified lines were drawn more sinuously from 

 the Rio Colorado, south of Bahia Blanca, northwards to cover the cultivated 

 regions of Buenos Ayres, and from post to post north-westwards to San Luis, here 

 bending; round south-westwards in the direction of San Rafael and the Plauchon 



