The plains are covered by a formation similar to that of the Argentine pampas and by the alluvial deposits of the present rivers.
The flora of Argentina should be studied according to natural zones corresponding to the physical divisions of the country - the rich tropical and sub-tropical regions of the north, the treeless pampas of the centre, the desert steppes of the south, and the arid plateaus of the north-west.
Evidence of this is to be found in the altitudes of the stations on the Buenos Aires and Pacific railway running a little north of west across the pampas to Mendoza.
The apparently uniform level of the pampas is much broken along its southern margin by the Tandil and Ventana sierras, and by ranges of hills and low mountains in the southern and western parts of the territory of La Pampa.
==Geology== The Pampas of Argentina are generally covered by loess.
In the north and on the pampas the north wind is hot and depressing, while the south wind is cool and refreshing.
The climate of the pampas is temperate and healthy, and is admirably suited to agricultural and pastoral pursuits.
The so-called " pampas-grass " (Gynerium argenteum) is not found at all on the dry lands, but in the wet grounds of the south and south-west.
The pampas were almost destitute of animal life before the horses and cattle of the Spanish invaders were there turned out to graze, and the puma and jaguar never came there until the herds of European cattle attracted them.
The " nandu " or American ostrich (Rhea americans), inhabiting the pampas and open plains of the Chaco, has in Patagonia a smaller counterpart (Rhea Darwinii), which is never seen north of the Rio Negro.
Of birds the number of species greatly exceeds that of the mammals, including the rhea of the pampas and condor of the Andes, and the tiny, brilliant-hued humming-birds of the tropical North.
Extreme variations in temperature are often produced by cold south-west storms from the Argentine pampas, which sweep across southern Brazil as far north as Cape Frio, the fall in temperature sometimes being 22° to 27°.
The range of the sloth is from the Guianas south into Minas Geraes, the armadillo as far south as the Argentine pampas and the ant-eater from the Amazon south to Paraguay, though it is found in the Amazon region principally.
The shallow lagoons of the llanos, like those of the Argentine pampas, are favourite fishing grounds for these birds.
Though an expert climber, it is by no means confined to wooded districts, being frequently found in scrub and reeds along the banks of rivers, and even in the open pampas and prairies.
It is most abundant in the open districts of Patagonia, but also ranges on to the Argentina Pampas, where it is now scarce.
To the Knot of Vilcanota with the basins of the Pampas, Apurimac, Vilcamayu and Paucartambo.
The southern valleys of this part of the sierra furnish streams which form the main rivers of Pampas, Pachachaca and Apurimac. These, uniting with the Mantaro, form the Ene, and the Ene and Perene (which drains the province of Tambo) form the Tambo.
P Y groups: - Eskimo, on Arctic shores; Dene (Tinneh), in north-western Canada; Algonquin-Iroquois, Canada and eastern United States; Sioux, plains of the west; Muskhogee, Gulf States; Tlinkit-Haida, North Pacific coast; Salish-Chinook, Fraser-Columbia coasts and basins; Shoshoni, interior basin; California-Oregon, mixed tribes; Pueblo province, southwestern United States and northern Mexico; Nahuatla-Maya, southern Mexico and Central America; Chibcha-Kechua, the Cordilleras of South America; Carib-Arawak, about Caribbean Sea; Tupi-Guarani, Amazon drainage; Araucanian, Pampas; Patagonian, peninsula; Fuegian, Magellan Strait.
Peru; Araucanian, Pampas; Aymaran, Peru; Barbacoan, Colombia; Betoyan, Bogota; Canichanan, Bolivia; Carahan, S.
The swamps covered with flax and giant bulrushes were often redeemed to the eye by sheets of golden-plumed toe-toe, a kind of pampas grass.
Land is being extensively put under wheat in the pampas of South America and in the prairies of Siberia.
Llamas are now confined to the western and southernmost parts of South America, though fossil remains have been found in the caves of Brazil, and in the pampas of the Argentine Republic.
The climate is admirably suited to cattle-raising, as the winters are mild and pasture is to be found throughout the whole year, but the proximity of the Argentine pampas is fatal to its profitable development.
The pampas-deer, M.
(B.) bezoartica, of the Argentine pampas is a much smaller animal, of paler colour, with three-tined antlers.
Paspalum, is a large tropical genus, most abundant in America, especially on the pampas and campos; many species are good forage plants, and the grain is sometimes used for food.
It is probably separated on the east from the recent deposits of the pampas by a great fault, which, however, is always concealed by an enormous mass of scree material.
On the "pampas" R.
The Pleistocene forms, whose remains occur abundantly in the silt of the Buenos Aires pampas, are by far the largest, the skull and tail-sheath in some instances having a length of from 12 to 16 ft.
Gynerium argenteum (pampas grass) is a native of southern Brazil and Argentina.
The climate of northern and central Chile is profoundly affected by the high mountain barrier on the eastern frontier and by the broad treeless pampas of Argentina, which raise the easterly moisture-laden winds from the Atlantic to so high an elevation that they sweep across Chile without leaving a drop of rain.
The Pampas-Grass, a noble species, introduced from Buenos Aires; it forms huge tussocks, 4 or 5 ft.
Long, formed by the confluence of the Tercero and Cuarto, whose sources are in the Sierra de Cordoba; it flows eastward across the pampas, and discharges into the Parana at Gaboto, about 40 m.
Next Spanish hides, with the tails still preserving their twist and the angle of elevation they had when the oxen that wore them were careering over the pampas of the Spanish Main--a type of all obstinacy, and evincing how almost hopeless and incurable are all constitutional vices.