96 BAfiBENSESS OF THE LLANO 



disappear but very slowly by fire and the axe, when Iho 

 trunks of trees are from eight to ten feet in diameter; 

 when in falling they rest one upon another, and the wood, 

 moistened by almost continual rains, is excessively hard. 

 The planters who inhabit the Llanos or Pampas, do not 

 generally admit the possibility of subjecting the soil to cul- 

 tivation ; it is a problem not yet solved. Most of the sa- 

 vannahs of Venezuela have not the same advantage as those 

 of North America. The latter are traversed longitudinally 

 by three great rivers, the Missouri, the Arkansas, and the 

 Red River of Nachitoches ; the savannahs of Araura, Cala- 

 bozo, and Pao, are crossed in a transverse direction only by 

 the tributary streams of the Orinoco, the most westerly of 

 which (the Cari, the Pao, the Acaru, and the Manapire) 

 have very little water in the season of drought. These 

 streams scarcely flow at all toward the north ; so that in 

 the centre of the Llanos, there remain vast tracts of land 

 called bancos and mesas* fright! ally parched. The eastern 

 parts, fertilized by the Portuguesa, the Masparro, and the 

 Orivante, and by the tributary streams of those three rivers, 

 are most susceptible of cultivation. The soil is sand mixed 

 with clay, covering a bed of quartz pebbles. The vegetable 

 mould, the principal source of the nutrition of plants, is 

 everywhere extremely thin. It is scarcely augmented by 

 the fall of the leaves, which, in the forests of the torrid 

 zone, is less periodically regular than in temperate climates. 

 During thousands of years the Llanos have been destitute 

 of trees and brushwood; a few scattered palms in the 

 savannah add little to that hydruret of carbon, that extractive 

 matter, which, according to the experiments of Saussure, 

 Davy, and Braconnot, gives fertility to the soil. The socia^ 

 plants, which almost exclusively predominate in the steppes, 

 are monocotyledons ; and it is known how much grasses im- 

 poverish the soil into which their fibrous roots penetrate. 

 This action of the killingias, paspalums, and cenchri, which 

 form the turf, is everywhere the same ; but where the rock 

 is ready to pierce the earth, this varies according as it rests 



* The Spanish words banco and mesa signify literally ' bench ' and 

 4 tahle.' In the Llanos of South America, little elevations rising slightly 

 above the general elevation of the plain are called banco? and me sat t 

 from their supposed resemblance to benches and tables. 



