The most striking feature of colonization in Patagonia is the very low density of population. The Census of 1914 gives 81,000 inhabitants altogether for the territories of the Rio Negro, the Neuquen, the Chubut, the Santa Cruz, and Tierra del Fuego. A well-kept ranch of 25,000 square kilometres has only a staff of about a hundred men at the most, counting strangers, settled on its land; three hundred inhabitants, or scarcely more than one to ten square kilometres. This population falls into two distinct classes. One is the class of proprietors with regular titles: a rooted and stable class. At first the Government granted enormous concessions, which were taken up especially by English buyers, but it now seeks to break up the land, and the plots which it puts on the market for new pastoral colonies have not more than 625 hectares. This is too small for breeding, no matter how good the situation may be, and there will inevitably be, one would think, a concentration of estates in the hands of a few proprietors. The other part of the population occupy lands which they do not own. They are displaced steadily as the regular concessions are sold to new ranches. They live, so to say, on the margin of colonization, and are more and more restricted to the poorest lands. Sometimes these intrusos or pobladores get hospitality for their herds on the land of some ranch in return for their services. They have little capital, and never make material improvements. They take no care to nurse the pasture, and it matters little to them if it is impoverished.
The climate divides Patagonia into two distinct regions. In the west, the moist Andean zone is suitable for cattle-breeding. About 1870 the Chileans of Valdivia hunted wild cattle in the Nahuel Huapi district. Similarly the Frontier Commission met large herds of wild cattle on the shores of Lake San Martin, which were not yet occupied. Sheep do not get on well in the moist zone, where the rains have washed out the soil and carried away the salts which seem to be indispensable to the sheep. It is the arid tableland that is the land of the sheep. There it has displaced cattle, even in the area which the early breeders at the end of the eighteenth century had filled with cattle. Between the sheep-area and the cattle-area is a mixed region, where the two are combined. It extends more or less according as the transition from a moist to a desert climate is gradual or sudden. It is especially important in the districts where colonization is already old, as in the Fuegian and Neuquen regions. It is lacking in districts where the colonization is recent (Chubut and Santa Cruz), where the sheep-breeders have had a free run as far as the Andes. The ranches of the Cordillera, which specialize in cattle-breeding, all have small flocks of sheep for their own use, their staff being so small that it does not pay to kill the cattle.
The sheep-area is by far the more extensive of the two. The patches of agricultural colonization are very scattered and small on its surface. They are restricted to the river-oases of the Rio Negro and the Chubut. These small tilled districts have preserved a remarkable economic independence as regards the pastoral zone, in which they seem lost. Thus the farmers on the Chubut exported their wheat to Buenos Aires until about 1900, and they still send their bales of dry lucerne there. Some of the ranches have tilled small oases in suitable places, but these are merely intended to increase their stores of fodder; not for their flock of sheep, but for the saddle-horses used in watching the estate and the draught-horses used for transport.
The pastoral capacity of the Patagonian scrub is, on the average, from 800 to 1,200 head of sheep to 25 square kilometres: less than a tenth that of the prairies of the eastern Pampa. The ranch fixes its residence in the best part of the estate, where there is least fear of a shortage of water, and where pasture is most plentiful. To this the sheep are brought periodically to receive disinfecting baths against the scab, and for shearing. These incessant movements toward the centre of the ranch cause an almost permanent strain on the pasture, and this is one of the chief anxieties of the breeder. The area of the estate is divided as soon as possible into sections (potreros) by steel-wire fences, which enables them to watch over the reproduction and improvement of the flock and make the best use of the pasture. Fencing is more advanced near the Cordillera, as timber for the posts is found there.
Certain districts are still uninhabited on account of the lack of water. Some of the sources of water are permanent. The water issues at the base of the volcanic rocks, when the underlying rock is impermeable, and above the various levels of the marl in the Patagonian swamps; for instance, in the cañadones round the Gulf of San Jorge. Besides this, the rain and melting snow leave on the surface of the tableland a great number of pools, which evaporate in the dry season. These are temporary supplies, the manantiales, to which the breeders are reduced over large areas of the tableland. Most of the stagnant sheets of water which are permanent are saline. The proportion of salt in them is very variable, and changes in each case according to the cycle of dry and wet years. The water of the Carilaufquen was fresh in 1900, and in 1914 it had become brackish, though it could still be used for the flocks.
Finding permanent sources of water is the first concern of the breeder. In some districts he has succeeded in tapping sheets of fresh water by means of wells. There are none of these wells in the crystalline zones, the closed hollows, where the sheets of water are often large, but they are always saline. Neither are there any in the red sandstone district, the dryest of all. In the western region the wells are sunk in the arid valleys, along the track of the underground stream. Thus the Picun Leufu, the visible course of which is lost seventeen miles above its confluence with the Limay, may be traced by a continuous line of wells. It is especially in the coastal districts that the wells have transformed the conditions of breeding. Water was first discovered at the foot of the dunes, along the coast itself (district of Viedma, San José, etc.). Since then deep borings have been made over the whole of the Tertiary platform on both sides of the lower part of the Rio Negro, north of San Antonio. There every ranch has its sheet-iron tank, sheltered by a clump of tamarinds, with a windmill to fill it.
All pastures are not equally available in every season. Those which are at a height of more thatthan 4,000 feet in the north, and 2,300 to 2,600 feet in the south, are covered in winter with a thick mantle of snow. These are summer pastures. During the winter the animals are brought down to the principal valleys or to sheltered cañadones below the level of the tableland. The mallin is, as a rule, a winter pasture. When it is too wet, however, it is treacherous, and the animals are buried in it. They have to wait for fine weather before going into it. The pastures, too, which have no permanent water supply, or have only manantiales, which dry up at the beginning of summer, can only be used during the winter. Hence each ranch has to have, besides its assured water supply, a suitable combination of summer and winter pasturage, and it is far from certain that this will be found on every estate, cut up geometrically for colonization, as they were, by the administration of lands.
THE VOLCANO PUNTIAGUDO.