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 Fe, was a valuable rampart, in the shelter of which a fairly large population had established itself round Concepcion del Tio. [9] _Nuevo plan de fronteras de la provincia de la Republica Argentina_ (Coll. de Angelis, vol. vi). The enlargements of the frontier were sometimes due to expansive movements of colonization, the breeders occupying new land beyond the line of forts and demanding protection, and sometimes to the arbitrary action of a Government which was eager to extend its territory, though it was still without the means of exploiting it. Roca has well shown the defects of this system of premature military occupation. "To go far away from the populated districts in acquiring new territory is, in my opinion, only an aggravation of the inconveniences of defensive war, and it places a desert between the new lines and the settled regions.... Invasions occur at once."[10] We should therefore be likely to make serious mistakes if we were to identify the history of colonization with that of military occupation. Moreover, the garrisons of the forts did not take a very active part in the exploitation of the soil. The plan which D'Azara proposed, of making _blandengues_ (lancers) colonists and rooting them to the soil by distributing it amongst them, seems to have been purely Utopian. His description of the frontier shows clearly how slight a hold the early colonization had on the Pampa, where the only relatively industrious element was represented by the groups of civilians (_paisanos_) who gathered about the works and moats of the forts. It was different on the Santiago del Estero frontier, where there was agriculture as well as breeding. Here the fort was identical with the village, and each soldier had his plot of wheat, maize, or water-melons.[11] [10] Letter to the Minister of War, October 19, 1875.