The constitution of the flock and the first occupation of the land have compelled breeders to undertake difficult journeys, and more than one of these proved disastrous. The earliest arrivals, driving their sheep along little-known tracks, could not avoid losses in crossing the arid parts of the tableland: parts which D'Orbigny, translating literally the Spanish word travesia, calls "crossings."70 When the ranch is established, the breeding does not necessitate any further movements of the flocks to a great distance, apart from certain special migrations, or "transhumations," which I will consider later. It is on each ranch, sometimes on each group of ranches combined in a single estate, that they pass alternately from winter to summer pasture. The only transport necessary is that of wool. The fleeces, which the west wind has heavily laden with dust, are collected in the sheds belonging to the ranch, or, in the case of the intrusos, on the premises of certain small traders (bolicheros) who are scattered over the tableland even at its extreme limits. Convoys of wagons then take them to the ports on the coast.

For some years now, however, wool has ceased to be the sole product of the ranches. A little before 1895 the first slaughter-houses, for killing the older sheep that were no longer fertile, were erected on the Straits of Magellan. Refrigerators have succeeded these, and were opened at Puerto Callegos and San Julian. A third refrigerator is being constructed (1915) at Puerto Deseado. In southern Patagonia, also, part of the flock is sent to the refrigerators or to the slaughter houses of the Pampean region. The creation of the refrigerator has compelled breeders to adapt their work to the new economic conditions. The merino breed is being eliminated by the Lincoln in all districts which feel the influence of the refrigerator; the Lincoln is of greater weight and quicker growth, but the merino survives in arid northern Patagonia.

Besides this, the establishment of the refrigerators has caused important movements of transport. The flocks which are to go to the refrigerators or the northern railways are moved in the good season, after the shearing, from November to April. The routes they take are not invariable. One of the most frequented, leading from the sub-Andean tablelands to San Julian, follows the Santa Cruz valley. When the land was cut up, there was no reason to foresee these movements, and nothing was done to facilitate them. The roads cross the ranches, which are compelled to allow it. It is a serious burden for some of them, unless they can make a profit out of their situation on the road by hiring pasture for the flocks as they pass.

The Andean zone itself is still mainly pastoral, but it is nevertheless far more varied and richer in possibilities of development than the tableland. Agriculture is already combined with breeding in that area.

The name vegas, which in the Puna and at San Juan means alpine pasture, is applied here to tilled patches in the Andean valleys. They are found in the north in the valley of the Neuquen, round Chosmalal. In the south, the valley of the Rio Pico marks the limit of cultivation. Irrigation is almost always necessary north of Lake Nahuel Huapi, where the vegas have, as a rule, a soil of coarse alluvia or permeable tufa, which dries up quickly. Water is plentiful, it is true, and increases in quantity rapidly as one travels southward. The chief obstacle to the extension of cultivation is the frequency of frost in spring and summer. The deep hollows of the sub-Andean depression south of Lake Nahuel Huapi, the height of which drops to 1,000 feet at the Bolson, and 1,600 feet at Diez y seis de Octubre, have no frosts in summer, and they sustain small agricultural communities. At higher levels, in the basin of the lake or on the vegas of the Traful and Lake Lacar, at an altitude of about 2,600 feet, the distribution of the summer frosts is closely related to the contour and lie of the land, which may facilitate or impede the circulation of the layers of cold air, and the play of what has been called atmospheric drainage. The valleys which are very open from west to east, at the outlet of the lakes, where the west winds have a free passage, are little liable to frost. Wherever frost is frequent, cultivation has to be restricted to fodder plants. The more favoured cantons, which grow wheat, rye and potatoes, help to feed the local pastoral population, and export part of their produce to some distance on the tableland.

Cattle-breeding is, like sheep-breeding on the tableland, practised both by the pobladores on public lands and by ranchers who have settled on regular concessions, which they have worked up and fenced round. The high alpine pastures, above the fringe of the forest, are partly used, from December to March, as summer-pasture. The forest also serves for pasture; it is a sort of common land, available both in winter and summer. Below the height of 3,500 feet the clumps of bamboos in the underwood provide shelter during the winter and fodder which is not buried under snow. The fires lit by the breeders have changed part of the primitive forest into a scrub which has been invaded by a leguminous climbing fodder, and it has superior pastoral capacity to the forest. East of the forest, the prairie, which is too much exposed to the winds, is not generally suitable for winter-pasture. The cattle take refuge in sheltered valleys and in the mayten thickets which follow the depressions. Bailey Willis puts the pastoral capacity of the virgin forest at 400 cattle to each 2,500 hectares, 600 for the burnt forest, and 350 for the sub-Andean prairies. The essential problem in connection with the question of completely developing the pastoral resources of the sub-Andean region is the problem of transit. There are no roads from one district to another and to the higher prairies. The fallen trunks which lie about the forest obstruct the way of the cattle. Collecting the animals for sale and watching them are both difficult.

It seems that the profit of exploiting the timber must necessarily be small. The forest, thinned by fire and difficult of access, is partly composed of trees that are too old. The libocedrus has disappeared from one-third of it. The larch, which is the most valuable, passes into Argentine territory at few places. Saw-mills are not so numerous on the eastern slope of the Andes as they are in the Magellan area.

The essential function of the forest is, according to Argentine experts on forestry, to control the water-circulation. In this land of glacial erosion and recent captures, where the water-courses have always a great variety of form, and there are lakes to make their output more regular, it is particularly easy to make use of hydraulic power. "White coal" will, Bailey Willis says, make a great industrial region of it, and plant an urban life in it. Bailey Willis, whose optimism and prophetic gift will not fail to surprise the European reader, has drawn the plans in detail of a future town of 40,000 souls at the eastern end of Lake Nahuel Huapi. The Patagonian land will supply the raw material of its industries; timber, leather, and wool.

One, at least, of the indispensable conditions of the development of urban life is fully realized in the district of Lake Nahuel Huapi and the Limay. It is a remarkable meeting-place of natural roads, and its economic value will increase in the future. It is the point where the road from eastern Patagonia by the sub-Andean depression, from the Gulf of San Antonio on the Atlantic, and from the Rio Negro by the Limay, and the roads that lead to Chile across the Cordillera, meet. The whole zone of the Andes between 36° S. lat. and 42° S. lat., the latitude of the southern part of the Chilean plain, has numerous and easy passes. There has always been close communication between the two slopes, and people have emigrated freely from one to the other. But north of 39° S. lat. the passes are rarely lower than 5,000 feet. They are covered with snow in the winter, and can be used for traffic only in certain seasons. It is not the same south of the volcano Lanin. That is the beginning of the glacial valleys which go to the heart of the Cordillera, some of them crossing the mountains from east to west. They have not yet been entirely explored. The Bariloche pass, south of the Tronador, by which the Chilean missionaries reached Nahuel Huapi in the eighteenth century, is no longer used. The Cajon Negro pass, west of Lake Traful, through which Bailey Willis traces the line of a southern trans-Andean railway, was only recently discovered, and the valleys which run into it on the Chilean side are not yet well known. The two best-known trans-Andean routes to-day are the Perez Rosales road, which leads from Chile to Nahuel Huapi by the north of the Tronador, and further north, the road from Lake Lacar to San Martin. Both these have received some attention, and the lakes are connected by telegraph or telephone. The frequent need to unload and reload makes the traffic costly, but it is permanent and is not interrupted in winter. The reduction of the export of cattle to Chile has cut down the traffic for a time, but it is sure to recover. The permanent importance of it is one of the facts most clearly written by nature upon the soil of South America.

It is not easy, in the absence of documents, to attempt to give for Patagonia as a whole a detailed description of the pastoral industry, and to follow step by step on the spot its efforts to adjust itself to the natural conditions. But the analysis may be attempted in regard to the region between San Antonio and Lake Nahuel Huapi south of the Rio Negro,71 the valley of the Rio Negro, and the tableland which stretches westward between the Neuquen and the Limay. This part of Patagonia is now easily accessible, and it is entered by two parallel railways. One starts from San Antonio on the Atlantic, and goes westward to Lake Nahuel Huapi. It has (1914) reached Maquinchao, on the tableland, mid-way across the Andes. The other starts from Bahía Blanca. At Choele Choel it enters the valley of the Rio Negro, and ascends it as far as the confluence of the Neuquen. Then it goes 130 miles westward as far as Zapala, at the foot of the first sub-Andean chains. Each of these lines is ambitious to attract the trans-Andeans. At all events, they are in a hurry to reach the humid zone at the foot of the Andes, which could maintain a busier traffic than the desolate tableland.

The railway from San Antonio, and the road which is a continuation of it west of Maquinchao, cover a distance of 320 miles from the Atlantic to the Andes, and cross five distinct regions. The first is the coastal plain, composed of horizontal marine Tertiary sedimentary rocks, both of sand and clay. The plain rises slowly toward the west, and it attains a height of 650 feet at a distance of seventy miles from the coast. This coastal platform divides, on the north-west, the enclosed hollow of the Bajo del Gualicho from the Gulf of San Antonio. Its surface is very even. The gravel on it has formed a sort of conglomerate, and in spite of appearances, this gravelly soil is not bad for vegetation. It quickly absorbs the rain-water, which thus escapes evaporation. The vegetation is comparatively rich. There are no springs, but the autumn rains sustain manantiales in the marly surface, and these do not dry up until the spring. During the summer the plain is deserted, and there is no water. But the flocks return in the winter and remain there until spring. There is very little snow, as the temperature is moderate. In spite of the density of the pastoral population in winter, the pasturage is not injured. The grass grows plentifully amongst the thickets. This is because the flocks leave the district before the season when the grasses flower and reproduce, so the next generation is secured. Part of the flocks which winter on the coastal plain pass the summer in the south-west, on the high basaltic tablelands of Somuncura. However, the whole of the surface of the tableland cannot be used permanently, or during the entire summer. There is plenty of water in spring, when the snows have melted. In the middle of the summer the flocks collect round the permanent springs, and they scatter once more over the mountain pastures during the autumn rains, before they return to the plain.

The second region is that of Valcheta. From Aguada Cecilia to Corral Chico the railway follows for sixty miles the edge of the outpour of lava from the south, which covers the Tertiary clays. In front of the basalt cliff the land dips in the north toward a closed depression, the Bajo de Valcheta, the bottom of which consists of clays impregnated with salt. Tertiary marine strata surround this hollow in the west and north, where they divide it from the Bajo del Gualicho, but here they form only a thin skin which covers the crystalline platform. The line of contact of the basalt and the Tertiary marls is marked by a series of good springs, and these give rise to permanent streams, such as the Arroyo Valcheta and the Nahuel Niyeu. At first they flow in a narrow valley crowned by basalts, with peaty prairies at the bottom, then over Tertiary marls, and, in the latitude of the railways, they pass into a gorge cut through the granites before losing themselves to the north in the salitral. A small agricultural oasis is sustained by the waters of the Valcheta.

The site of Valcheta has an exceptional importance in the story of Patagonian colonization. It marks a necessary stage in the Indian track from the Atlantic to Nahuel Huapi, which is now followed by the line of the railway. Musters halted there. The track from Choele Choel, on the Rio Negro, to the southern coast and the Santa Cruz also passed by there. It was so much used, says Ezcurra, that the hoofs of the horses had hollowed it.72 The Argentine village dates from 1890. At first it lived by supplying fodder to the convoys of wagons which carried the wool. The railway has suppressed this traffic, and the only outlet of the oasis to-day is the small port of San Antonio, where the wool is shipped, and where the district is unsuitable for any kind of cultivation.

Like the coast region, the Valcheta district seems marked out by its moderate altitude to serve as winter pasture. In point of fact, it is used during the whole year. The springs do not dry up in summer. The streams which flow from the south toward the Bajo de Valcheta are permanent. In addition, a few wells have been bored in the Tertiary strata. Contrary to experience on the coast, therefore, cattle can be kept here during the summer. There is less chance for the grasses to reproduce, and the pasture tends to become impoverished.

The third zone, 130 miles from the coast, is that of the tableland of the Cerros Colorados, where low masses of red granite rise like an archipelago amongst the Tertiary formations deposited in the intervening depressions. In the west its altitude rises from 650 to 1,300 feet. It is one of the poorest parts of the tableland, and the size of the flock is reduced to 600 head to the square league. The naked rock crops up, not covered, as it is further east, by a bed of gravel. In the valleys there is little water, and it lies very deep. There are no periodical removals of the animals. Winter and summer they remain within range of a few poor springs, which are caused by various outcrops of lava of limited extent; and they leave these, and wander over the tableland, only in the rainy season.

Beyond the Cerros Colorados the line rises rapidly, and at Maquinchao it reaches the basin of Lake Carilaufquen. This occupies the bottom of a closed depression, at an altitude of 3,000 feet, dominated on every side by a plateau of lava, toward which, in the south, a number of important valleys run (Nahuel Niyeu, Quetriquile, Maquinchao). These valleys rise in the south in the basalt plateau, at a height of 4,000 and 4,700 feet, and have no running water except at their upper ends. South of Carilaufquen they open upon a broad plain, round which there is a sombre cornice of lava, about 350 feet high. Water has collected on the plain, which consists of alluvial beds redistributed by wind: angular pebbles from the terraces, fine dust from the mallinas, and sand from the dunes round the lake.

This region is much better than that of the Cerros Colorados. There are many springs at the base of the lava-flows, on the sides of the valleys, and it has as yet not been necessary to look for the subterranean sheets which accompany some of the valleys. The elevated basin of the Quetriquile, though it is only occupied by intrusos, seems to have a particularly high pastoral density, and, I am told, feeds 500,000 sheep. In the western part of the region the spring is late, and there is risk of snow during the lambing season. There are, however, no rams there; the lambs are brought from Maquinchao. This arrangement of special zones for the multiplication of the flock enables them rapidly to improve the breed. Here again there are no removals of the animals to a great distance in order to use the pasture. The vegetation of the valleys suffered from the continuous presence of the flocks during the years of drought before 1914; the reproduction of useful grasses was prevented. There is, however, less danger here than on the Cerros Colorados, because the mallinas are extensive, and they suffice for feeding the sheep during the periods when the manantiales of the tableland dry up, and the animals are confined to the valleys.

The fifth region comprises the high ridge which divides the basin of the Carilaufquen from Nahuel Huapi, the water of which flows northward toward the Limay and southward toward the Chubut: successive eruptions have covered the surface with lava and ash, which at Añecon rise to a height of 6,700 feet. The granite platform which emerges in the north, at the Cerro Aspero and the Quadradito, rises to a height of 4,400 and 4,700 feet, and in some places presents a bold and rejuvenated aspect. The whole has been cut up in all directions by erosion, and it affords comparatively easy means of getting about, which the Indian tracks have followed. Below the higher slopes the valleys deepen into gorges, and these broaden out in the soft tufa and are lost at the cross-streams of lava or the outcrops of the granite. In so varied a land, with such marked differences of altitude, the winter and summer pastures are always close together. Precipitation is more plentiful than at a distance from the Cordillera; the pasturage is richer, and the size of the flock rises to 1,600 sheep to the league. The sheep pass the winter on the lower slopes, where they are sheltered from the winds and the snow. They descend to the mallin when the dry season sets in and makes the soil firm. In summer they go on to the tablelands, where the pastures extend to a height of 5,000 feet.

Bailey Willis, studying the improvements that might be made in the pastoral processes, concluded that the essential point was to use each pasturage in its best season, and establish a carefully considered rotation on the various lands. This system, which alone would enable them to nurse the natural resources of the scrub in the way of plants for fodder, is used to-day in only a small number of districts—in the east, where the flocks winter on the coastal plain and spend the summer on the Somuncura tableland, and in the west, round the Añecon, where the summer and winter pastures are not far from each other. The custom ought to be general. The area which ought to be reserved for winter pasture comprises the coastal plains, the whole of the low-lying district round Valcheta, and the lower part of the valleys to the south of the Carilaufquen. They are less extensive than the available summer pastures, but their capacity could be enlarged by developing the irrigated areas in the Bajo de Valcheta, and sowing lucerne in the mallinas of the basin of the Carilaufquen. The low valleys round the Carilaufquen ought to be reserved for winter pasture. In the summer the sheep would be taken south to the higher-level valleys, which afford permanent pasture. From there they would spread after the melting of the snow, and after the first rains in autumn, over the high tablelands which surround them.

This plan is obstructed in the first place by the actual terms of ownership, which were imprudently fixed before the examination of the country in detail had been concluded. Thus the Maquinchao ranch, in the lower valley, does not own the upper valley with the summer pastures that ought to belong to it. A more serious obstacle is that it is extremely difficult to remove the sheep. It is not merely roads that are wanting, but a water supply at the various stages.73

Between the railway that runs from San Antonio to Lake Nahuel Huapi and the Rio Negro, there is a desert region about seventy miles in width. Red sandstone predominates in it, and it remains uninhabited. North of this travesia the valley of the Rio Negro opens. Its width between Neuquen and Patagones ranges from five to fifteen miles. Its slope diminishes gradually toward the bottom (from 0.67 to 0.49 per 1,000 above Chelfaro; from 0.45 to 0.29 per 1,000 above Conesa).

The sandstone and marl cliffs which enclose it become gradually lower as one goes downward. They dominate the valley at a height of 650 feet at the confluence of the Neuquen, and are only 100 to 130 feet high at Patagones. At the foot of them are broad terraces cut by dissymetrical ravines, in which the beds of sandstone outcrop on the western slope, exposed to the winds, while the eastern slopes are covered with gravel. On the banks of the river there is a strip about two miles wide with abundant herbaceous vegetation between lines of willows. This is covered by the normal floods. The remainder of the river plain, to the foot of the cliffs, has only a thin scrub, with dunes at intervals. Saline clays here overlie the river gravels. The level of the underground water, which is fed by the river, sinks lower as one goes from the banks toward the cliffs. Few parts of the tableland have so desolate an aspect as the bottom of these great Patagonian valleys, when they have not been transformed by irrigation. The pasturage is poor. At Conesa, however, the valley (costa) is used as summer pasture when there is a shortage of water on the surrounding tableland (planeza).

The water-supply is good, the volume of the river ranging from 200 to 900 cubic metres a second. Low water lasts from February to April (end of the summer). From May to July the river has sudden and violent floods—an effect of the autumn rains. The curve sinks again in August and September, to rise once more in October and December, when the snow melts on the Andes. The Limay, the upper basin of which contains large, lacustrine sheets, is more regular than the Neuquen, which has very pronounced low-water, as well as dangerous floods in the autumn. The first attempts at irrigation date from 1885, when the canal of the Roca colony was dug. Others were made lower down at a later date. The co-operative groups organized for the administration of the canals have not been quite as successful as might have been expected. The advance of agricultural colonization has been slow. Costly preparatory work is needed to level the ground and organize the drainage, otherwise saline patches form and spread like leprosy at the expense of the cultivable areas. Lastly, the centre of the valley is exposed to floods.74

The chief crops are lucerne, cereals, and the vine. All the efforts and hopes of the colonists are now centred upon the vine. It is for the purpose of extending the vineyards that they are endeavouring to secure more workers. These are a singularly mixed lot, Chileans from the Neuquen rubbing shoulders with Latin immigrants (Italian and Spanish) from the region of the Pampas.

The lucerne is made up in bales and exported by rail to Bahía Blanca and Buenos Aires. The economic life of the agricultural oasis of the Rio Negro is no more connected with that of the pastoral tableland than is life on the Chubut. Neither sheep nor cattle are fattened on the Rio Negro. It is a curious contrast to the spectacle offered by the Andean regions of western and north-western Argentina, where for generations there has been a close association between the breeding industry of the scrub and the fattening on the lucerne-farms. This is because the currents of the cattle-trade are not here as permanent and stable as they are in the north. The time when the convoys of Pampean cattle bound for Chile used the valley of the Rio Negro preceded the agricultural colonization of the banks of the river. The conquest of Patagonia put an end to this traffic. There was an interval of twenty-five years between the period of the export of Pampean cattle to Chile and the export of cattle from the Neuquen to Buenos Aires, to which I will refer presently. As to sheep-breeding, it did not for a long time rear the animals for the meat-market, and it is only a few years since it found transport necessary. The farmers of the Rio Negro, who have little capital, and who sell and are paid in advance for their dry fodder, have not yet been able to take advantage of the reorganization of the cattle-trade.

West of the confluence of the Neuquen and the Limay the railway ascends the sandstone tableland, from 1,700 to 3,000 feet high, and goes as far as the foot of the first sub-Andean chain, the Zapala ranch. The eruptive rocks here have thrown up the sandstone, and the profiles raised north and south of Zapala, across the Sierra de la Vaca Muerta and the Cerro Lotena, cut through folds of Mesozoic strata which have been reduced by erosion to the level of the plateau. One already feels the vicinity of the Cordillera. Pasture is plentiful, the mallin is thick, and springs abound. The sheep-area stretches westward of Zapala, as far as the Rio Cataluin and the Rio Agrio. East of Zapala, on the other hand, the desolate condition of the country gets worse and worse. The supplies of water dry up in the summer, and the entire zone that lies east of 70° W. long. is useless, on account of the lack of permanent water, except as winter commonage. Hence, transhumation is here indispensable. It has been practised for a long time on the Chilean slope of the Cordillera from the latitude of Coquimbo and San Juan to the north of Lake Quillen. At present it tends to disappear from the Andes of the Neuquen.75 But there is still transhumation on the Argentine side. The sheep of the plateau, driven from their winter pasture when the water dries up, ascend the Cordillera. Sometimes the mountains are not yet free from snow. In that case the journey is delayed, and the sheep feed on the way, to the great detriment of the land they cross.

There are many routes, and frequently they coincide with those which were formerly taken by the cattle of the Pampas in ascending to the passes of the Cordillera. Groeber mentions a transhumation track south of the Rio Barrancas and Lake Carri Lauquen. From the left bank of the Neuquen the flocks ascend by Chosmalal and Butamallin to the pasture of the Pichachen pass, or by Las Lajas to the Pino Hachado pass. From Zapala and the tableland further south they go to spend the summer in the Cataluin Cordillera, where the number of sheep in summer is calculated to be 70,000. Others go still further, to the source of the Alumine and the Arco pass. The volcano Lanin almost marks the southern limit of the zone of transhumation. The chief group of migrating sheep comes from the district of the Coyunco, the Cañadon Grande, and the Picun Leucu.

Transhumation is practised only by the intrusos. They go from the unowned lands of the tableland to the unowned lands of the Cordillera. The renting of winter pasture to owners is quite exceptional. The concessions of land granted by the Argentine Government are steadily reducing the area of the migrators in the Cordillera, and also the ways of communication between the tableland and the mountains. The proprietors do not care to receive the migrating flocks, and they put obstacles in their way by enclosing the land. The routes of the transhumation are now fixed by the spaces which remain open between the enclosed ranches. Moreover, the migrating intrusos are haunted by the fear of finding the winter pasture occupied by others during their absence, and they have no proprietary title. The splitting up of the land and the organization of ownership will before long lead to the extinction of the practice of transhumation, and the greater part of the winter pasturage will be turned into permanent pasture by boring wells and nursing the water-supply.

The district round the Zapala ranch has become very busy since the construction of the railway, which has deeply affected the conditions of life there. It has made a sort of capital of Zapala. It is curious to contrast the renaissance which has followed upon the appearance of the railway in this district with the much less material changes which it has made at Maquinchao. The life which the railway concentrates at Zapala includes not only the wool trade, as at Maquinchao, but also the cattle trade. The herds which are to be exported gather round the ranch at the same time as the tropas of wagons, and a good price is paid for the right of pasturage. While the Maquinchao line ends at the port of San Antonio, which is merely fitted up for the export of wool, the Zapala railway feeds the refrigerator at Bahía Blanca. It joins up with the network of railways of the Pampa. Sheep arrive at Zapala, not only from the surrounding district and from the Neuquen, but from a good part of the Rio Negro, and even the Chubut. The convoys of animals coming from the south find it best to keep near the Cordillera, where the pasturage is better. Only a few of them descend the Limay as far as Senillosa. From Zapala to Senillosa there is no suitable road in connection with the railway, and further east it is necessary to go as far as Choele Choel to find tracks which lead to it. The exporting of the sheep lasts five months, from November to March.

Zapala station is also a point of convergence of herds of cattle. There are people at Zapala who still remember the time when the cattle brought from the Pampa to go to Chile passed through their valley. Although these exports of Pampean cattle to Chile ceased after 1885, the whole Andean region of the Neuquen still lived entirely on the Chilean market until very recently. The attraction of the Chilean market is one of the reasons for the survival of transhumation. It was to the advantage of the Argentine breeders to keep near the Cordillera and the passes through which the buyers came from Chile in the summer. The life of the small centres in the upper valleys which developed rapidly after the conquest (Chosmalal, Ñorquin, Codihue, Junin, and San Martin) was bound up with the Chilean cattle trade, and was reflected on the opposite side of the Andes in the prosperity of the corresponding markets in Chile.

In the years immediately preceding 1914, a sudden revolution upset the cattle traffic on the Neuquen, and the attraction of Buenos Aires took the place of that of the Chilean market. The commercial influence of Buenos Aires was first felt in the wool-market. The tropas of wagons which brought wool to Zapala loaded up, in exchange, with the flour and salt that were needed for sheep-breeding in the pastures of the Cordillera (pastos dulces). The import trade followed the path traced by the export trade. The small Chilean wagons which still cross the Cordillera now only bring to the Neuquen the coarse flour of Chile, haricot beans, and wine. They return empty to Chile. After the wool-buyers, the cattle-merchants of Buenos Aires next found their way to the Cordillera. The centres where the sales of cattle for Chile used to be held are now in decay, and have lost part of their population. The cattle are sent to the fattening centres on the Pampa, or to the Bahía Blanca and Buenos Aires markets. Thus we have under our eyes, unexpectedly, in the north of Patagonia a transformation that occurred gradually half a century ago in all the western and north-western parts of Argentina. In its many forms it is the essential fact in the modern history of Argentine colonization. The more distant provinces are detached in succession from foreign markets, and the whole national life is being organized round the great economic focus which the region of the Pampas has become.

CHAPTER VI
THE PLAIN OF THE PAMPAS

The Pampean landscape is doubtless one of the most uniform in the world. Its monotony is tiring to the eye; it is partly responsible for the mediocrity of most of the descriptions of the Pampas. But this uniformity is an advantage for the purpose of colonization. Attention has often been drawn to the rapidity with which plants and animals introduced by Europeans spread in the Buenos Aires district, and, pushing ahead of the breeders and farmers, colonized the Pampas. In the second half of the nineteenth century, when the whole extent of the plain beyond the ancient Indian frontier was occupied, the development of it was so much easier because it was possible to use simpler and more uniform methods of exploitation. It needed neither large capital nor long personal experience on the part of the immigrant. Basques and Italians who had only just landed could take an active part in it almost without apprenticeship. The primitive groups of population could advance from one zone of the plain to another and take with them their own methods of farming and breeding, their own form of rural economy.

A close study will, however, enable us to detect appreciable physical differences in the Pampean plain. Neither climate nor soil is the same all over it.

The name "Pampa" chiefly means a vegetal growth, a prairie. Its limits are the frontier of the scrub (monte), and strange as it may seem, it is still difficult to trace them exactly. North of Santa Fé, between the Salado and the Paraná, the Pampa stretches as far as Fives-Lille, a little beyond 30° S. lat.76 On the Central Norte and the Central Argentine lines the fringe of the monte reaches to Fuertin Inca and Malbran, about 170 miles north-west of Santa Fé. It then turns south-east and south, passing round the entire depression of Los Porongos and Mar Chiquita; and the line from Santa Fé to Córdoba crosses it at Francia and approaches the Rio Secundo. South of the Rio Secundo it goes westward and joins the foot of the Sierra de Córdoba south of the Rio Tercero (at the stream Tequia). From this point to La Cambre, some sixteen miles east of San Luis, the prairie extends as far as the edge of the sierras, and penetrates into the southern half of the Conlara depression, between the hills of Córdoba and of San Luis (Pampa de Naschel). The mimosa forest enters the steppe in narrow belts along the Rio Quinto to within a few leagues below Villa Mercedes, along the Rio Tercero as far as the confluence of the Saladillo, and along the Salado to the south of Santa Fé. There are, in addition, many isolated clumps of chañares and more extensive patches of wood in the north-west corner of the prairie (Santa Fé province). The monte along the Salado is continued south of Santa Fé along the Paraná, as far as the point where the chief arm of the river reaches the cliffs on the right bank, at San Lorenzo. This is the domain of the ombu, a tree with thick trunk and naked roots which is found scattered over the prairie in the Paraná region as far as south of Buenos Aires.

In the west, between San Luis and the mouth of the Colorado, the transition from the Pampa to the monte is gradual. Just as at Santa Fé, the approach of the monte is announced by the appearance of chañares, in the south-west corner of the Córdoba province and on the southern slope of the Sierra de la Ventana. The monte, properly so called, though impoverished, invaded by the jarilla, and mainly composed (as in northern Patagonia) of dwarf mimosas, covers the area of the Pampean sierras on the left bank of the Chadi Leuvu and the Colorado. Between this area and a line passing through Rancul, Anguil, Atreuco, and Bernasconi, where the naked prairie begins, there is a mixed zone which one may call the calden zone. This mimosa, a near relative of the algarroba, which has a wider range than the other plants of the monte in this latitude, forms woods at intervals in the south of the San Luis province and on the flanks of the parallel valleys of the central Pampa. Between these woods the tableland is generally covered by the prairie, with occasional patches of chañares. About twenty-five miles east of Buena Esperanza the line from San Rafael touches the far corner of a forest of caldenes, which stretches south-westward, and reaches the Rio Salado about 35° 30′ S. lat. Beyond Buena Esperanza it keeps on the prairie as far as the crossing of the Salado, which here marks the limit of the monte. The Rio Negro line passes directly from the prairie to the Patagonian scrub mid-way between Bahía Blanca and the Colorado.

Within these limits the prairie extends without a break. The sierras of the Buenos Aires province have no arborescent vegetation.

The zone of the prairie, intermediate between tropical Argentina and the sub-desert regions of western Patagonia, has a medium rainfall. It decreases gradually from north-east to south-west. There is a rainfall of 1,200 to 1,000 millimetres on the lower Paraná, and only 400 to 600 millimetres on the western edge of the Pampa. The zone which lies between the 800 millimetres and 600 millimetres average is more than 270 miles in breadth. But what is most characteristic of the climate of the Pampa is the equal distribution of the rain throughout the year, and the absence of a real dry season. In this the Pampa differs from the surrounding regions, both in the south-west and the north. At Buenos Aires the six months of the (relatively) dry season yield, nevertheless, 44 per cent. of the total rainfall, and at Bahía Blanca 40 per cent. This regularity diminishes in proportion as one approaches the coast. At Rosario the six months of the dry season only yield 30 per cent. of the year's rain; at Villa Mercedes (San Luis province) 25 per cent. When one goes beyond the limits of the prairies the ratio of rain in the dry season decreases rapidly; it is only 20 per cent. at Córdoba and 18 per cent. at San Luis. At Córdoba, the curve of the rainfall indicates a typical tropical regime, with a summer maximum and a very low minimum in winter. Passing south-eastward from Córdoba, at Bellville, Villa Maria and especially Rosario, the dryness of the winter diminishes, and at the same time a secondary minimum appears in the middle of summer (January-February). At Buenos Aires, the form of the curve changes completely. The summer minimum is almost as low as the winter minimum, and most of the rainfall is in the spring (September) and the beginning of the autumn (March).77

These various shades of the Pampean climate are of essential importance in the history of colonization and the spread of cultivation. The belt of summer rain is the belt of maize-growing, whereas the cultivation of wheat requires spring rain and a comparatively dry summer.

While the isohyetic curves, which represent the precipitation for the whole year, are orientated from north-west to south-east, the curves of rainfall during the cold season, from April to September (dry season in the north), cut diagonally across the preceding, and are oriented directly north and south. Bahía Blanca receives in winter as much rain as Rosario, and General Acha (in the district of the central Pampa) as much as Córdoba. Unless one attends to this, one cannot explain the extension of wheat-growing, in the south-west, as far as the 400 millimetre curve, and even beyond it on the Atlantic coast.

The relief of the Pampean plain is known fairly accurately, thanks to the observations made along the railways. The ground rises slowly toward the west. The 100-metre curve describes a deep gulf some 300 miles west-south-west of Buenos Aires. The belt comprised between 100 and 150 metres above sea-level is more than sixty miles broad in the latitude of Santa Fé, and 130 miles in the latitude of Buenos Aires. Beyond the 150-metre curve the land rises rapidly toward the west and north-west, and reaches 400 metres in the Córdoba district and 500 in the Villa Mercedes district. It is at the altitude of 150 metres, and the break in the inclination which this marks, that the Rio Quinto is lost, near Amarga, south of General Lavalle.

The ridge between the Pampa and the basin of the Salado in the south of the San Luis province is about 450 metres above sea-level. South of the province of Buenos Aires the Sierras de Tandil and de la Ventana are joined together by a ridge which does not fall below 200 metres. Certain irregularities of the surface, such as the depression of Mar Chiquita to the east of Córdoba, the thrust of the plateau on the right bank of the Paraná, south of Villa Constitución and San Nicolas, can, apparently, only be explained by recent tectonic movements.

The Pampean deposits which cover the plain rest upon a rocky base of which the salient representatives are the sierras of the province of Buenos Aires and the hills at Córdoba and San Luis. This base also appears east of the Pampean basin in the granite island of Martin Garcia, in the middle of the estuary of the Plata, and in the hills on the coast of Uruguay.78

Underneath the even sheet of the alluvial deposits the surface of the sub-Pampean platform is very irregular. Its shape has been discovered by deep borings in search of arterial waters. It has been warped and cut up by faults, some of these deformations being probably synchronous with the formation of the Pampean deposits which have concealed them as they have been produced. A subterranean rocky ridge continues the Sierra de Córdoba southward and joins it with the sierras of the Colorado. The granite emerges at Chamaico, on the western railway, and on both sides the borings have passed through great depths of clay and sand.79 This ridge isolates the eastern Pampa from the sub-Andean chains, and marks the limit of the area with sheets of underground water. In the north of the Pampean region, between the Sierra de Córdoba and the Paraná, the loose continental formations are more than 2,000 feet thick at Bellville, and more than 3,500 feet north-west of Santa Fé (fodder farms of San Cristobal and El Tostado). At Buenos Aires the granite has been found 985 feet below the surface.