The spheres of primitive colonization in southern Patagonia on the coast still differ from each other in regard to density of population. But breeders in search of unoccupied land have not hesitated to push beyond. In 1895 and 1900 they passed west of the Gulf of San Jorge toward the basin of the Sanguerr and the Genua, (establishment of the Sarmiento colony, south of Colhuapi, 1897: establishment of San Martin on the Genua 1900). Since 1900 the population has also advanced up the Santa Cruz and the Rio Chico as far as the zone of the Andes, and the lagoon which still existed twenty years ago, between the district of the Sanguerr and that of Lake Argentino, and is easily recognized on the maps of the Frontier Commission, has been almost entirely filled up. The story of colonization in the northern part of the Patagonian Andes is more complicated. Immediately after the campaign of 1883 the valleys of the Neuquen were invaded by Chilean immigrants, half-breeds of the frontier, who cannot always be easily distinguished from pure Araucans. A certain number of Chilotes, and even Germans from the southern colonies of Chile, were mixed with the half-breeds. This stream of immigration had begun before the conquest. As early as 1881 Host notices that there are at Chosmalal various families of Chilean farmers who held their lands from the Indian _cacique_. During the summer they took care of the migratory herds from the Chilean plain. Once the country was pacified, they grew rapidly in number. It was they who provided the manual labour for the placer miners of the Neuquen, where gold began to be worked in 1890. The area of Chilean colonization extends from the Rio Atuel, where Villanueva found Chilean immigrants in 1884, to the south of Lake Nahuel Huapi, where Chileans were still met by Vallentin in 1906, on the Rio Pico, close to 44 deg. S. lat.[66] South of Nahuel Huapi there is no regularly used route across the Cordillera.[67] The Chilean colonists of the southern zone came from the north, therefore, along the eastern foot of the Andes. Bailey Willis calculated that there were 2,000 Chileans in a total population of 3,500 in the sub-Andean area from Nahuel Huapi to Diez y seis de Octubre. The total number of Chilean immigrants may be about 20,000. It is not on the increase, as immigration from Chile was suspended from 1890 to 1895. Since the reconstruction of the frontier the Chilean Government has tried to bring back part of the emigrants to its own territory. Many have gone to settle in the valley of the Lonquimay. In 1896 Moreno saw traces everywhere in the valley of the Collon Cura of the departure of Chilean colonists who had left the country. [66] C. Villanueva, "De Mendoza a Narguin," _Bol. Instit. Geog. Argent._, v. 1884, pp. 171-4. [67] Chilean woodcutters have sometimes got as far as the eastern valleys in search of larch, but these were nomads who did not settle.