Roca begins the second sweep in 1879,…

Roca begins the second sweep in 1879, with six thousand soldiers armed with new breech-loading Remington rifles, who reach Choele Choel in two months, after killing thirteen hundred and thirteen natives and capturing over fifteen thousand.

From other points, southbound companies make their way down to the Rio Negro River and the Rio Neuquén, a northern tributary of the Negro.

Together, both rivers mark the natural frontier from the Andes to the Atlantic Ocean.

This attack leads to a large migration of Mapuches into the zone around Curarrehue and Pucón, Chile.

Many settlements are built on the basin of these two rivers, as well as a number on the Colorado River.