Colonization does more than emphasize the individuality of each of the natural regions. It connects together different features, and blends them in a complex vital organism which goes on evolving and renewing itself.
The occupation of the whole of the soil of Argentina by white colonists is quite a recent event. The second half of the nineteenth century was characterized by a rapid territorial expansion, and over more than half the country the expression "new land" must be taken literally. It is only one generation since it was taken from the Indians. There can be no question here of tracing the history of the relations between the white population and the free Indians of the Chaco and the Pampa. The most formidable of these were, in the north, the Abipones and the Tobas. On the Pampa, the foes of the colonists were Indians of Araucanian descent, Ranqueles, Pehuenches, etc., who came down from the mountains and took to horses. At the close of the eighteenth century the frontier of Buenos Aires was on the nearer side of the Salado, and was bordered on the south-east and north-west by the fortresses of Chascomus, Monte, Lobos, Navarro, Areco, Salto, Rojas, and Melincue. The proposal of D'Azara to extend it as far as the Salado was not carried out, and it was not until 1828 that there was a fresh advance westward.[5]
The new frontier, which would not be altered until 1875, passed by Veinte Cinco de Mayo and Blanca Grande, at the north-western extremity of the Sierra de Tandil. It included the entire region which lies between the Sierra de Tandil and the lower Salado, where the village of Tandil had been established in 1823. In addition, a line of forts stretched from Blanca Grande in the south-west to Bahía Blanca. The expedition sent in search of a port south of the mouth of the Plata had not found any nearer site that was suitable. But Bahía Blanca was to remain an isolated advance post until 1880, sharply separated from both the colonized zone of the Pampas and the establishments on the Patagonian coast.
While the cultivated area was thus growing toward the south, it was being reduced in the north of the province of Buenos Aires and the south of Córdoba. The lands of the lower Rio Cuarto were not occupied. About 1860 (Martin de Moussy) the farthest establishments in this sector were S. José de la Esquina and Saladillo on the Tercero. The road to Chile by the Rio Cuarto, Achiras, and San Luis was threatened. The advance of colonization in this zone was at first in the west to Villa Mercedes on the Rio Quinto. The line of the Rio Cuarto by Carlota was reoccupied, and before 1875 the frontier had been pushed back to the Rio Quinto, where it joined the forts of southern Buenos Aires by way of Sarmiento, Gainza, and Lavalle.
At last, in 1878, General Roca abandoned the classical methods of fighting the Indians, and took the offensive. He deprived the Indians of their refuges to the south of San Luis and the Central Pampa, and threw them back toward the desert. The Argentine troops followed in their steps as far as the Andes and the Rio Negro. There are to-day few traces in the immense territory that was won of the indigenous population. Its extreme mobility had masked its numerical inferiority.[6]
The history of the northern frontier is much the same. At the end of the eighteenth century the Spanish outposts ran along the course of the Salado. To the north of Santa Fé, at Sunchales, Soledad, and San Javier, they protected the direct route from Santa Fé to Santiago del Estero. These outposts were abandoned during the revolutionary period, and the Indians advanced as far as the suburbs of Santa Fé. The roads both to Santiago and, by the Quebracho Herrado, to Córdoba were cut.[7] Urquiza reorganized the Santa Fé frontier, first as far as San Javier, then below 29° S. lat. between Arroyo del Rey on the Paraná and Tostado on the Salado. The expedition of 1884 brought the Argentine army as far as the Bermejo, and broke the resistance of the Tobas. The forts which, more to the north, guarded the province of Salta, on the further side of the Sierras de la Lumbrera and Santa Barbara, had been dismantled at the beginning of the nineteenth century, as the tribes in this part of the Chaco were not hostile.[8]
The memory of the fights with the Indians is so completely blotted out to-day, and the menace of invasion by the tribes has been so rapidly extinguished, that it is difficult to realize fully the profound influence they once had on colonization. The line of forts was a frail barrier that was constantly broken through. The Indians of the Pampa stole cattle from the ranches of Buenos Aires, and sold them in Chile. Colonel Garcia calculates in 1816 that about 40,000 animals were stolen every year.[9] Colonel Roca gives the same figure in 1876. The Pampa put no natural difficulties in the way of the movements of the Indians, no points which might serve as bases for the frontier. D. Pedro Pablo Pabon points out that the proximity of the Sierra, instead of giving protection to outposts in the Tandil region, would be an additional source of insecurity, as it increased the difficulty of keeping watch. In the north the Indian incursions followed the clearings in the scrub, avoiding the dense and impenetrable parts. The lagoon of Mar Chiquita, to the west of Santa Fé, was a valuable rampart, in the shelter of which a fairly large population had established itself round Concepción del Tio.