Chapter VI: The Plain of the Pampas (1)

The limits of the prairie--The rains--The wind and the
formation of the clay of the Pampas--The wind and the
contour--The zones of colonization on the Pampas--Hunting
wild cattle and primitive breeding--The sheep-farms--The
ranches--The region of "colonies"--The region of lucerne,
maize, and wheat--The combination of agriculture and
breeding--The economic mechanism of colonization--The
exchanges between the different zones 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.

[76] On the left bank of the Salado, west of the Resistencia
railway, a great gulf of low prairie penetrates into the
forest of the Chaco in the north, almost as far as 28° S.
lat., but it has rather the character of one of the floodable
clearings of the Chaco (_esteros_) than of the temperate
Pampa.

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]

[77] Argentine Mesopotamia, which is a continuation of the
Pampean region from the climatological point of view, is also,
even in its northern part, without the rigorous dry seasons of
the Chaco. Ascending the Paraná, from Corrientes to Posadas,
just as in passing from Córdoba to Buenos Aires, one notices
that the winter minimum decreases, and a secondary maximum
appears in the spring. The predominance of the spring rains,
which is a characteristic of southern Brazil, is conspicuous
on the middle Uruguay. On the lower part of that river the
rain-system approaches that of Buenos Aires, with maxima
in spring and autumn, a principal minimum in winter, and a
secondary minimum in summer.

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]

[78] While the Pampean deposits lie immediately on the
crystalline and Paleozoic formations in the sierras of the
lower Colorado and of the central Pampa, in the south of the
province of Buenos Aires and in Uruguay, they are, on the
eastern edge of the Sierra de Córdoba, separated from it by
red sandstones and conglomerates of uncertain age, perhaps
synchronous with the continental red sandstones of Corrientes
which outcrop east of the Paraná and have been known since
D'Orbigny's time as "granitic sandstones."

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.

[79] At Rancul, in the east, 660 feet of loess overlying red
sandstone: at Telen, in the west, 2,800 feet of sand, marl,
sandstone and gravel.

The Pampean formation consists almost entirely of loose deposits, sand and clays of various sorts. There is no gravel.[80] Even in the vicinity of the sierras the beds of gravel, with round or angular pebbles, are almost always covered by clay, and are exposed only in the banks of the streams. Olascoaga mentions the surprise of the _gauchos_ of General Roca's army when they found Patagonian pebbles on the ground during their stay at Choele Choel on the Colorado, in the course of the campaign on the Rio Negro. Officers and soldiers dismounted to pick them up. Sand and clay form a thick bed of continental alluvia. The Tertiary maritime transgressions, which have left their mark in the clays and limestones of the left bank of the lower Paraná, and the layers of shells at San Pedro on the right bank, never penetrated far into the interior of the Pampean region, and one finds no trace of them when one leaves the coast or the river.

[80] Roth claims to have found gravel in the San Nicolas
_barranca_ on the Paraná. I have myself found small rounded
flints in the clay of the Chaco at Tartagal. But these
deposits probably come from the left bank of the Paraná, where
the beds of river gravel are considerable.

The source of the elements which compose the Pampean alluvia is very uncertain. Their composition does not clearly show their origin. The clays are comparatively rich in calcareous matter, which seems to indicate that they do not come from tropical America or the upper basin of the Paraná. Wright and Fenner insist upon the high proportion of siliceous glass of volcanic origin which they contain, which points to an intense eruptive activity during or before their formation.[81] Doering had already noticed in the Córdoba region the prevalence of beds of volcanic ash, which become thicker as one approaches the sierra. It is certain that the Pampean sierras have had their share in the formation of the Pampean beds. But the main mass is probably of Andean origin. However that may be, as soon as one gets away from the fringe of the mountains, the only variety noticeable in the lands of the Pampa is that which they owe to the conditions in which they have been deposited.

[81] In Ales Hrdlicka, _Early Man in South America_
(Smithsonian Instit. Bull., 52, Washington, 1912).

River deposits strictly so called, estuary deposits, lagoon deposits, æolian deposits, æolian deposits redistributed by water, river deposits redistributed by wind--all these different types are represented in the Pampean formation, but their relative importance is still disputed.[82]

[82] Many attempts have been made to classify the Pampean
lands, but the results cannot be regarded as final. Ameghino,
who is first and foremost a palæontologist, has done a service
in showing the futility of these geological divisions based
upon the actual surface of the deposits (colour, fineness,
etc.). But even palæontology gives rather uncertain results,
as it is impossible to recognize and follow step by step
the various stages of the movement of the fossils. All the
classifications of the Pampean are based upon a study of two
groups of sections. The first group comprises the cliff on
the right bank of the Paraná from Rosario to Buenos Aires
and the coastal cliff which is a continuation of it, with a
break from Enseñada at Mar Chiquita to Bahía Blanca. Ameghino
has recognized there a thick series of æolian deposits
separated by several discordances, the oldest elements of
which, at Bahía Blanca, belong to the Miocene. The second
group comprises the cliffs which enclose the valley of the Rio
Primero above and below Córdoba. Doering and Bodenbender in
this case describe two stages of æolian loess, each covered by
torrential gravel.

From the study of these sections geologists have drawn
certain conclusions as to the movements which have affected
the soil of the Pampa and the changes which the climate has
experienced. These conclusions have in each case only a local
value, and they have not yet been co-ordinated. The majority
of the observers, from Doering to Bailey Willis and Rovereto,
seem not to have taken into account sufficiently the fact that
in the continental formations the most diverse deposits may
come next to each other in the same series, according to the
particular process of deposition, and that their alternation
does not imply a general change in the conditions of erosion.

When we confine ourselves to studying the actual conditions in which the deposits were formed, we are first struck by the poverty of the hydrographic network of the Pampa. It is slight except in the vicinity of the sierras, where the slope of the ground is pronounced, and in the eastern area, on the right bank of the Paraná and Entre Rios, where the climate is more humid, and the streams flowing over an impermeable soil more numerous. The only one of the streams born in the Pampean sierras that reaches the Paraná is the Rio Tercero or Carcaraña. All the others dwindle as they descend, and disappear in a low-lying district marked by lagoons which they only reach in time of flood. The floods themselves never bring the Rio Cuarto and the Rio Quinto and the Salado de Buenos Aires into touch with each other. The waters of the northern slope of the Sierra de Tandil, and even those of the Sierra de Curumalal, on the other hand, reach the Salado after the rains, either by way of streams which drain the strings of lagoons, or by flood-sheets, which spread over large areas.

The watercourses of the plain are unstable in their direction. The traces of their wanderings remain in the form of stretches of alluvial sand crossing the fine æolian clays. These river sands sometimes spread over extensive areas, the distribution depending upon a hydrographic scheme which is now partially effaced. The sands of the departments of General Lopez (south of the Santa Fé province) and General Arenales (Buenos Aires province), where the Salado is now developed, were probably brought by the Rio Cuarto, and mark an earlier junction of the Cuarto and the Salado. These sands run along the Salado as far as the confluence of the Saladillo, and the contrast between the light soil and the clay of the bank of the Paraná is so striking that the sand has long been regarded as a marine deposit, indicating an ancient shore. Along the Saladillo also, north-west of the Guamini lagoons, there is a sandy belt which corresponds with an important direction taken by the actual flow of the river, crossing the Bolivar and Veinte Cinco de Mayo departments.

While the agency of running water in transporting alluvia is confined to certain sections of the plain, the action of the wind is seen over its entire surface. The wind everywhere supplements or replaces running water. Like running water, it classifies the elements it conveys, and selects them according to their weight and size, the finest clays being deposited in the moist eastern zone and the coarsest sands in the sub-desert zone of the west. The mechanism of erosion explains this contrast. The grains of sand that are driven by the wind travel at the surface of the ground as long as the vegetation is too sparse to fix them. If one goes further east, to a moister district with a thicker vegetal carpet, the grains of sand no longer move at the surface of the ground, but the wind still carries fine particles of clay, which it bears to a great height. The bed of clay does not at all imply an arid climate, as is said sometimes, but corresponds to the region of the steppes, with moderate rainfall. It is, however, during dry seasons that the deposition of clay is at its greatest. Darwin mentions that after the droughts of 1827-1830 in the area round the Paraná, the marks were buried under dust to such an extent that one could no longer recognize the limits of the various lands. Apart, however, from these sorts of floods or storms of dust caused by the _pampero_, the summer atmosphere is clearly laden with dust, which colours the skies in the east of the Buenos Aires province, as far as Entre Rios.

The contour of the plain bears, like the soil, the double marks of erosion by running water and æolian erosion. The rivers of the Pampa, when they leave the sierras, flow between high cliffs, the height diminishing as one goes downward. Presently these _barrancas_ become low, approach each other, and at last merely mark the banks of a larger bed which the floods fill. There is no trace of valleys. Bailey Willis, surprised at this weakness of watercourses that have, nevertheless, an appreciable fall, attributes it to the fact that the cycle of erosion opened by the last upheaval of the Pampa has not yet had time to penetrate into the interior. In reality, it means that here we are at the limit of the zone of erosion by running water, and that in this climate the essential factor in shaping the landscape is the wind.

The region of the right bank of the Paraná (east of the Salado), which alone has a complete hydrographic network, must be considered apart. From the latitude of Rosario to that of Buenos Aires it is cut by flat-bottomed valleys which are sometimes a hundred feet deep. The excavation of these valleys is due to an upheaval which raised this part of the Pampa above the base-level. The rapids of the lower Carcaraña also bear witness to this resumption of excavation. Farther on an inverse movement has put the bottom of the valleys below this level, and led to their being filled up (lagoon deposits of the Lujanense of Ameghino). South of Buenos Aires the upheaval has been less important, and the valleys are not so deep. Some of them (middle Salado and its tributaries on the left bank) are now occupied by long lagoons with steep banks, branching along the side-valleys, and these owe their origin to the same negative movement, subsequent to the excavation of the valleys. The upheaval did not extend to the eastern part of the province of Buenos Aires south of the Salado, a low-lying flat area, badly drained, exposed to floods, the contour of which has been minutely studied in connection with the construction of a great network of drainage-canals. North of Rosario, on the only slightly permeable clay, the water circulates, after rain, not by means of valleys in the proper sense, but along broad and almost imperceptible depressions (_cañadas_) where the current is slow, and the water dries up in the dry season. Their general relations are not yet known.

The loose deposits of the Pampean offer little resistance to erosion. The cycles are run through rapidly, and the traces of earlier cycles are faint, and are soon effaced.[83]

[83] Certain features of the hydrographic network clearly have
the character of having been superimposed: that is to say, the
path of the watercourses has been bequeathed to the actual
plain by former erosion-surfaces, which have now disappeared,
on which the valleys were originally imposed. That is why
in the district of the confluence of the Colorado and the
Chadi-Leuvu the valleys pass from Pampean deposits to the
crystalline sierras, which were at one time entirely covered
with water.

An ancient erosion-surface, dissected by the existing valleys, has survived in the south-west of the Pampean plain, thanks to the presence on the surface of a sheet of hard limestone, the _tosca_. The _tosca_ is the result of the concentration of calcareous elements contained in clay at the surface in a dry climate. The formation of it implies a prolonged stability of the surface on which it has accumulated. Like the deep decomposition-soils in moister regions, it indicates a peneplain on which erosion has ceased. The bed of _tosca_ covers the whole district between the Sierra de Tandil and the Sierra de la Ventana, the south-western slope of the Ventana, and most of the area of the central Pampa. In the north it does not go beyond the line from Buenos Aires to San Rafael. Its eastern limit goes almost by Ingeniero Malmen, Monte Nievas, and Atreuco, where it joins the southern bank of the lagoons of Carhue and Guamini in the east.[84] In some places the tosca is about forty feet thick.

[84] In the vicinity of San Luis and Córdoba the hard strata
which are called _tosca_ are beds of eruptive ashes.

To-day the region of the _tosca_ forms a plateau cut by narrow valleys, sometimes 200 feet deep, west of the Sierra de la Ventana and in the central Pampa. These parallel valleys, with few ramifications, generally lying south-west to north-east, open to the east upon the Pampean plain about the frontier of the Buenos Aires province. On the other hand, the southernmost of them begin at the foot of the Ventana, and seem to blend in the south-west with a general depression that is still little known, though it appears to end at the bottom of the estuary of Bahía Blanca. None of them has permanent running water.[85] The origin of the dry valleys of the _tosca_ is one of the most obscure problems of the morphology of the Pampean plain. Perhaps they are due to æolian erosion, like the depressions which are found on the plateau of the Colorado and the Rio Negro further south.

[85] The surface of the _tosca_ tableland is further
punctuated by a great number of closed depressions of various
depths: long tunnels (_dolines_) which can only be explained,
apparently, as an effect of the dissolving of the limestone by
water.

The action of the wind in shaping the landscape is more clearly seen in the formation of the dunes. When one starts from Buenos Aires or Rosario, and gets beyond the region of the level Pampas, the dunes are the first feature to meet the eye on the surface of the plain. The first fresh dunes are encountered at Carlota, on the line from the Rio Cuarto; at Lavalle on the line from Villa Mercedes; and at Trenque Lauquen on the line from Toay. The dunes spread northward as far as the latitude of Mar Chiquita, but do not enter the Chaco. They are also found in parts of the scrub on the west, but their proper domain is the western border of the steppe, the upper part of the plain at the foot of the Sierra de Córdoba, the south of the San Luis province, and the central Pampa.

Any accident that causes the vegetal covering to disappear, such as the tread of cattle near a drinking place or an enclosure, is enough to set æolian erosion at work. The wind raises the sand in a sort of tossing sea. Then the dune assumes a circular shape. A depression appears in the centre, and it deepens until it reaches the average level of the plain. Frequently there is a little lake in it. From this point onward the deformations are less rapid. The vegetation again creeps over the ground, and the dune falls a prey to the rains, which slowly reduce its mass.

In the central Pampa, where the elevation is considerable, the dunes do not form separate circular patches, but stretch in lines parallel to the valleys--sometimes in the heart of the valley, at other times backing against one of its slopes.

Far to the east of the zone of the quick dunes, in the south of the Córdoba province and the centre of the Buenos Aires province, there are certain soft undulations, covered with vegetation, with a sandier soil than that of the plain around them. These are dead dunes. The district of the dead dunes is characterized by the extreme irregularity of the surface-soil, the humus, which gains in richness and depth, as a general rule, as one goes eastward, because there it is in some places covered by recent æolian deposits.

The distribution of the dead dunes is connected with the stretches of river sand across the Pampa, which have offered an easy victim to the winds. A line of dead dunes follows the upper course of the Salado in the district of Junin and Bragado. On the line from Buenos Aires to San Luis one crosses it between Chacabuco and Vedia, and then one comes again upon the horizontal plain, which has fresh dunes, only further west, at 120 miles from Villa Mercedes. Its elevation is so conspicuous on the level plain that the first breeders who used its pasturage gave it the emphatic name of the _cerillada_. D'Azara correctly appreciated the nature of it. "It is," he says, "only a dune of very fine sand." It is only a few yards high. The dead dunes of the Bolivar and Veinte Cinco de Mayo departments, which Parchappe described, have a more conspicuous relief, and in their disposition sometimes remind us of the fresh circular dunes with a central lagoon. The lines of coastal dunes in the eastern part of the Buenos Aires province obstruct the proper flow of the water there, and form a group apart, which must be clearly distinguished from the dunes on the plain.[86]

[86] Outside the districts with quick and dead dunes, a
frequent type of landscape on the Pampa is a plain thinly
sown with very small lagoons, generally circular, between
which develop a series of barely perceptible undulations. The
inequality is at times so slight that one only notices it
by the contrast between the vegetation of the lower and the
higher ground. This type of landscape, which is especially
seen in the district of Lincoln or of Nueve de Julio, is
due to the action of the wind on a plain where the level of
the underground water is near the surface. This level marks
a limit below which æolian erosion does not take place: a
sort of base-level. The periodic variations of level of the
underground water reduce or enlarge the undulations of the
surface.

Thus the impression of monotony which the Pampa makes in us is corrected to some extent by close observation. High and low land alternate on it. Parchappe himself had noticed the contrast between the area that stretches from Buenos Aires to the Salado, with its soft undulations and its well-developed hydrographic network, the horizontal plains on the right bank of the Salado, with their irregular dunes, and the southern plateau of the _tosca_ between the Sierra de Tandil and the Sierra de la Ventana.

* * * * *

We may now distinguish the following regions in the Pampa as a whole:

1. The central part of the Santa Fé province forms what is called the district of the "colonies": that is to say, the domain of the colonies established two generations ago, and the zone in which the type of cultivation introduced by them took root. The chief crops here are wheat and flax. Hedges of service trees (_paraisos_) surround the fields. In contrast with the parts of the Pampa which have remained naked, the region of the colonies seems a veritable grove. It stretches westward beyond the frontier of the Córdoba province, and it reaches the fringe of the _monte_ between San Francisco and Mar Chiquita. For the north, Miatello gives 30° S. lat. as the normal limit of the wheat-growing area; beyond this it suffers both from the low rainfall of winter and the excessive rainfall in summer. As a matter of fact, the large estates only reach this latitude on the line from San Francisco to Ceres. On the Resistencia line, north of Santa Fé, they stop at 30° 30' S. lat. In the intervening district the limit of the region of the colonies almost coincides with that of the department of Castellanos, about 30° 45' S. lat. The area lying between this line and the northern edge of the Pampa is given up to breeding. In the south the region of the colonies stretches as far as Las Bandurias and Irigoyen.

2. South of the region of the colonies, the tableland on the right bank of the Paraná, west of Rosario and San Nicolas, is the maize region, the corn belt of Argentina. Flax is generally cultivated as well as maize. It is the agricultural country _par excellence_ of Argentina. The soil, of fine clay, dark red in colour and retentive of moisture, and the abundant summer rains, are very suitable for maize. The limits of the maize region describe an arc of a circle round Rosario with a radius of 60 to 100 miles. They do not quite reach the frontier of Córdoba in the west, and they leave out the entire south-western corner of the Santa Fé province. The maize belt touches the Paraná between 32° S. lat. and the Baradero. In the north it passes suddenly into the region of the colonies. In the south, on the other hand, there is at the edge of the corn belt an extensive transition-area, where maize and wheat occupy pretty much the same surface; it stretches as far as the Rio Salado de Buenos Aires.

3. The region of the lucerne farms is much larger. It comprises the whole north-west corner of the Buenos Aires province, from the Salado, in the district of Junin, to the southern limit of the Nueve de Julio and Pehuajo departments, and as far as the latitude of Guamini. The limit of the lucerne farms does not include the lands of the central Pampa, but advances westward and takes in part of the Pedernera department in the San Luis province. The lucerne farms run along the San Rafael line to Batavia, and at this point they reach the limits of the colonized zone. In addition, the zone of the lucerne farms includes the whole south-eastern part of the Córdoba province, as high up as the line from Villa Mercedes to Villa Maria, and the southern part of the Santa Fé province. In the whole of this area, fifteen to twenty-five per cent. of the surface is planted with lucerne. The conditions required for its cultivation are a moderate depth of the underground water and a light soil that allows the roots to penetrate easily. The eastern belt of clays is not good for lucerne, which survives there for much less time than in the west, where it may live fifteen or twenty years.

The lucerne belt is above all a great breeding area for horned cattle, as sheep-pasturage injures the lucerne. It is not nearly so monotonous, however, as the preceding regions. In the south-east, in the Buenos Aires province, the creation of the lucerne farms was undertaken at a time when agricultural colonization had already begun. We therefore find two types of exploitation side by side. The cultivation of maize enters it in the south-west, in spite of the comparatively unfavourable climatic conditions. The centre of the lucerne area in the south of the Córdoba province is also a great agricultural zone; but there agriculture is directly connected with the creation of the lucerne estates. It is, in fact, entrusted to colonists who till the ground for four or five years, and restore it to the owners sown with lucerne at the expiration of their lease. The crops consist almost exclusively of wheat and flax. Lastly, in the west (San Luis province and extreme south-west of Córdoba province) the soil gets increasingly more sandy, and the climate drier. A single tillage suffices to destroy the natural vegetation and clear the place for lucerne. The lucerne fields have been created by the breeders themselves, the sole masters of the region, without the aid of the colonists.

4. Beyond the lucerne belt, at the point where the plain rises toward the Sierra de San Luis and the Sierra de Córdoba, the subterranean water sinks deeper. This zone at the foot of the ranges, unsuitable for lucerne, yet with a soil comparatively rich in humus, has been taken up by agricultural workers. The wheat area extends, in the San Luis province, as far as Fraga and Naschel, in the Conlara depression. The maize area extends to Oncativo, in the Córdoba province, between the Tercero and Secundo rivers, where the summer rainfall is heavier. Thanks to the nearness of the mountains, this area has a water-supply for irrigation, and this sustains several small centres of good farms.

5. The south of the Buenos Aires province and the central Pampa are the wheat zone. The bed of _tosca_, which is not far below the soil, does no harm to the wheat except in years of drought. The valleys, where the _tosca_ is interrupted, and the dunes, where the soil is deep, are very carefully used for lucerne fields of limited extent. Wheat-growing seems now, both in this and the preceding zone, to have reached its limit, as the dryness makes it improbable that there will be any extension westward.

6. Lastly, the east of the Buenos Aires province, the centre of which is fairly indicated by the little town of Dolores, is the only part of the Pampean plain which has not been reached by agricultural colonization. The land lies low, and is badly drained. The only change that has taken place in the vegetation is a progressive improvement due to the hoofs of the cattle during their long stays there. This pastoral area is clearly limited in the south by the Sierra de Tandil. In the north it is continued in the more varied region that lies between Buenos Aires and the lower Salado, where the alternation of winter pasture on the dry lands and summer pasture in the valleys, encourages the best methods of breeding, and has made it the region of the dairy industry.

In the Entre Rios province the limit of the large estates of wheat and flax is marked by 32° S. lat. The part of Entre Rios which extends north of 32° and the Corrientes province do not strictly belong to the Pampean region.

* * * * *

Extensive breeding was the first form taken by white colonization on the Pampa. The word breeding is, in fact, hardly the correct name for an industry that mainly consisted of hunting, and was wholly distinct from the patient and advanced methods used at the same time in the northern provinces.

"The real wealth of the province of Buenos Aires," says Dean Funes, "was, and always will be, the trade in hides" (_la pellejería_).[87] A good part of the hides exported came from the hunting of the wild cattle and horses which had grown numerous on the area of the Pampa beyond the Rio Salado.[88] It was mainly after 1778, when trade with Spain had been authorized and there was an increased demand for hides, that the hunting of these ownerless beasts was taken up. Two thousand Spaniards from Buenos Aires, Santa Fé and Mendoza hunted every day, says D'Azara, killing an animal for each of their meals in addition to those they killed for hides. From 1775 to the Revolution, the Spanish Government made continuous efforts to regulate and reduce the massacre of the herds. It laid down penalties for every person selling hides that did not bear his own mark; it farmed out the right to hunt animals with no mark, and organized the destruction of wild dogs, etc. The ranches developed under shelter of this legislation. Still, the Revolution did not witness the end of this cattle-hunting. D'Orbigny took part in 1828 in two hunts of wild horses (_baguales_) in Entre Rios. The Argentine _gaucho_ long retained the ways of a hunter rather than those of a breeder in the strict sense; witness Urquiza's soldiers who, says Demersay, during the campaign of 1846, when they could not find trees to which they could fasten their horses, killed cattle and tied the reins to their horns.

[87] _Ensayo de la historia civil del Paraguay, Buenos Aires,
y Tucumán_ (3 vols, in 16^{mo}) Buenos Aires, 1816, t. iii, p.
214.

[88] The number of wild animals and the area over which they
roamed have often been exaggerated. It does not look as if
they ever covered the whole of the Pampean plain. A salter who
crossed Patagonia and the whole of the Pampa in 1753 (_Voyage
du San Martin au fort de San Julian_, Coll. de Angelis, v.)
only found wild herds near the Salado frontier, and he knew by
this that he was close to the ranches. At the beginning of the
nineteenth century there were no wild cattle left on the right
bank of the Paraná. There were still some in Entre Rios.

Passing from the hunting country to the zone of ranches, one notices that the main work of the breeder is to prevent his cattle from running wild. "The ranches of this country," said Dean Funes, "having been set up on immense plains, on which it was not easy to confine the herds within fixed limits, it sometimes happened that the animals went vast distances in search of water or pasture, and ended by being regarded as wild and ownerless," When D'Azara wants to show that the ranches of Paraguay are superior to those of Buenos Aires, he is content to say that there the animals are tamer (_mansos_). With the wild animal (_alzado_) is contrasted the _de rodeo_ animal: that is to say, the cattle which are rounded up periodically in the centre of the ranch to be taken to the pasture where they must live (_aquerenciar_). It is the difficulty of preventing the dispersal of the herd that fixes the price of the _rincones_ (surrounded by inundated areas) of Corrientes, in which the animals are captives.

MacKann's description of pastoral life in the Buenos Aires province in the middle of the nineteenth century give us a very clear impression of the stage of transition between exploiting the natural increase of a herd that multiplies without man's intervention, and breeding in the strict sense. The value of a horse in the former case is almost exclusively the cost of breaking it in. The breeder is actually anxious when he sees his horses increase, as he fears he may not have the resources for breaking them in. The most formidable of the dangers that threatened the feeble discipline of the herd was drought. That in the year 1827 was a disaster. The animals left the ranches in a body to go southward, where they mixed.[89]

[89] The water problem is not as important for the history of
colonization in the Pampean region as in the north. Primitive
breeding was confined to natural supplies of water, lagoons
or streams, and to shallow wells (_jagueles_) dug down to
the superficial sheet, which is generally not deep, but is
liable to dry up. As colonization improved, the breeder, and
subsequently the farmer, were better equipped for boring
wells, and no longer feared drought. They got down to the
deeper waters, semi-artesian (Buenos Aires district) or
artesian (west of the Santa Fé province, round San Francisco).
In other places the superficial waters, which are fresher
than the deeper layers, were used by adapting new types of
filters to the wells (Buena Esperanza district). The only two
districts where the quest of water offered any difficulty are
the south-west corner of the Pampean region and the northern
extremity of the prairie in the Santa Fé province. The sheets
of water are very irregular there, often saline, and it was a
long time before the ranches got an assured supply.

One remarkable circumstance is the importance of the dunes in
connection with the distribution of the underground water. The
rain-water accumulates in the dunes and flows slowly through
the sand to the sub-soil. The level of the underground sheet
in the clay on which the dune rests is always nearer the
surface in the neighbourhood of the dune. The dune itself has
often a greener vegetation than the land around it. Nothing
is more surprising than to find at Medanos (west of Bahía
Blanca), in the middle of a plain of arid aspect, fields of
lucerne and orchards lodged in the hollows of dunes that are
still fresh. In the whole of the Buenos Aires province the
dead district of the dunes is, on account of its water-supply,
a good place for habitation. D'Azara notices the numerous
water-spots which ran along the foot of the dead dunes of the
Cerillada. All round were the white bones of the _baguales_.
In the valleys of the central Pampa, where the sheet of water
in the centre of the valley is often saline, the underground
water improves gradually as one approaches the line of the
dunes.

Revolutions and wars interrupted the work of taming the cattle. When Galvez went from the Córdoba province to Buenos Aires at the end of the Rosas Government, he was struck by the condition of the ranches.[90] Many of them had been confiscated, or their owners driven into exile. Cattle were no longer marked, and they had become wild. The troubles of the emancipation-period were much less injurious to the Buenos Aires breeders than to those of Entre Rios. The Entre Rios herd was almost annihilated during the revolution, and some of the ranchers of the left bank crossed to the right bank of the Paraná. After 1823 the pastoral wealth of Entre Rios was rapidly restored, thanks to raids on Brazilian territory. They were so profitable that the whole population took part in them. In 1827 the inhabitants of Bajada went there in such numbers that the town was half deserted. Every day thousands of cattle were collected on the bank of the Uruguay, and crossed the river. Some of them were even taken beyond the Paraná, to the Santa Fé province. Woodbine Parish confirms this rapid restoration of Entre Rios, of which D'Orbigny was a witness. But this period of prosperity did not last long. The war with Uruguay, under Rosas, again ruined the Entre Rios ranches, and the drought of 1846 helped to scatter the remaining herds. Extensive breeding is only lightly rooted in the soil. The chief centres of production change their locality, as the political circumstances change, from one part of the Pampean plain to another.

[90] V. Galvez, _Memorias de un viejo_ (Buenos Aires, 3 vols,
in 16^{mo}, 4th ed, 1889).

Primitive breeding affords few examples of periodical migration for the better use of pasturage. In 1822, in the course of a journey amongst the Sierras de Tandil and de la Ventana, Colonel Garcia noticed that the Indians kept their cattle round the temporary lagoons of the plain in the winter, and went up to the mountain-streams in summer. Transhumation movements of this kind were difficult for the creole ranchers, whose fairly large herds could not be handled easily. The Chascomus breeders, however, at the close of the eighteenth century, drove their cattle to the low banks of the Salado during the dry season.[91] Garcia also notices the importance of the Salado pastures for the ranches of Salto, Areco, and Lujan.[92] The need to remove the herds in the dry season, and to find _invernadas_ within reach of the former ranches, was due to the change brought about in the natural vegetation of the Pampa and the spread of the _pasto dulce_. The annual herbs which compose the _pasto dulce_ die and disappear after fertilization. Until the autumn rain they leave the ground quite naked, whereas the tough grasses of the _pasto duro_ afforded a thin but permanent pasture.

[91] _Diario de un reconocimiento de las guardias y fortines
que garnecen la linea de frontera de Buenos Aires_ (1796), by
D. Felix de Azara (Coll. de Angelis, vi.).

[92] _Nueva plan de fronteras de la Provincia de Buenos Aires
por el Colonel Garcia_ (1816, Coll. de Angelis, vi.).

* * * * *

The first improvements of the pastoral industry of the Pampa are connected with the development of sheep-breeding. Exports of wool began about 1840, and made great progress after 1855 (17,000 tons in 1860, 65,000 tons in 1870). From 1850 to about 1890 the economic returns on sheep-breeding were far better than on cattle-breeding. During the whole of this period the multiplication of sheep farms was only restricted by the supply of workers. The first shepherds had been Basques, in the south of the Buenos Aires province, and Irish, in the north. The owner settled them as small farmers in the _puestos_ on the edge of the ranch, the central part of which was devoted to cattle. They could thus, while they guarded their sheep, see that the limits of the estate were respected, and prevent the cattle from roaming.

Wool was for a long time the only product of the sheep-rearing industry. From 1866 onward it was decided to use the hides and tallow also. As the material of the grease-works was cheap, they spread all over the sheep zone. Many ranches had works of their own. From 1867 to 1877 the _saladeros_ that had been built long before for killing cattle undertook the slaughter of sheep on a large scale. The number of sheep sold to the _saladeros_ rose to 3,000,000 a year. In 1880 the first cargoes of frozen mutton were sent abroad. The creation of the grease-works had made no difference to the breeding, but the building of the refrigerators brought about a rapid transformation of the flock. The Lincoln breed, heavier and more meaty, displaced the fine-wool Merinos. This substitution of Lincolns for Merinos is now complete throughout the Pampean region.

Until 1880 sheep-rearing was concentrated east of the Salado, north and south of Buenos Aires, beginning with a line that passes through Quilmes, San Vicente, Pilar, and Campana, which marks the limit of the suburban zone. In addition it had spread on the right bank of the lower Salado as far as the foot of the Sierra de Tandil, in an area where the first stations date from 1823, though the population did not make much progress until after 1855. About 1880, after the pacification of the Pampa, the sheep-farms began to expand westward. It was then that the wool of the _pasto fuerte_ appeared on the Buenos Aires market. It came from the Azal district in 1870, from Olavarria in 1880, from Bolivar in 1885, and from Villegas in 1890. The Census of 1889 ascribes 51,000,000 sheep to the province of Buenos Aires; that of 1895 gives much the same figure (52,000,000). Detailed comparison of the two enumerations shows that the expansive movement to the west continued, and was completed during this period. The flocks in the north-west zone of the province (Lincoln, Villegas, Trenque, Lauquen) more than doubled; the flocks of the south-west area (Alsina, Puan, Bahía Blanca, Villarino) continued to grow, and increased by a third. Those on the lands of the central Pampa increased threefold. On the other hand, in the departments north and south of the Sierra de Tandil, where colonization is older, sheep-breeding is stationary. The north-east and south-east areas, between the Paraná and the Salado, have diminished: one losing a fifth, and the other a half, of its flocks.

From 1895 onward the number of flocks of sheep on the Pampean plain decreased rapidly. The number of sheep had sunk from 34,000,000 in 1908 to 18,000,000 in 1915 for the Buenos Aires province; from 2,800,000 in 1908 to 2,300,000 in 1914 for the central Pampa. The reduction was general, and found in every district; but it was not equally great everywhere, and did not begin at the same date in every district. Sheep-breeding has almost entirely disappeared from the eastern belt, east of the Salado, which was its cradle. South of Buenos Aires the sheep are giving place to horned cattle, and they had almost disappeared by 1908. North of Buenos Aires they survived long, but the reduction of the flocks has only been the more rapid since 1908. This corresponds with the advance of maize-growing. In six years the Bartolome Mitre and Pergamino departments have lost, respectively, four-fifths and five-sixths of their sheep. In the north-west of the Buenos Aires province the sheep began to be reduced at the time when the lucerne farms were founded, about 1900. The decrease has since gone on uninterruptedly. The actual flocks represent one-fourth of the flocks of 1895. In the south-west (wheat belt) there was a rapid shrinkage before 1908, but it seems to have almost been arrested since then, thanks to the combining of sheep-rearing with wheat and oats. The actual flocks are about one-half the flocks of 1895. Finally, in the area north of the Sierra de Tandil the sheep retreat before the cattle, as they do further north, but they are not so completely wiped out as in the lucerne belt, and the flocks are still two fifths of the flocks of twenty years ago.

In the province of Entre Rios and south of Corrientes the number of sheep continued to rise until 1908, but the increase is only in the northern departments, outside the agricultural belt. The southern departments, which are large growers of wheat and flax, lost one-third of their flocks between 1895 and 1908.