32 THE SOMTmERO PALM. 



high. It 13 probably a new species of the genus corypta; 

 and is called in the country palma de sombrero, the footstalks 

 of the leaves being employed in weaving hats resembling 

 our straw hats. This grove of palm-trees, the withered 

 foliage of which rustles at the least breath of air the 

 camels feeding in the plain the undulating motion of the 

 vapours on a soil scorched by the ardour of the sun, give the 

 landscape an African aspect. The aridity of the land aug- 

 ments as the traveller approaches the town, after passing 

 the western extremity of the lake. It is a clayey soil, which 

 has been levelled and abandoned by the waters. The neigh- 

 bouring hills, called Los Morros de Valencia, are composed 

 of white tufa, a very recent limestone formation, imme- 

 diately covering the gneiss. It is again found at Victoria, 

 and on several other points along the chain of the coast. 

 The whiteness of this tufa, which reflects the rays of the sun, 

 contributes greatly to the excessive heat felt in this place. 

 Everything seems smitten with sterility; scarcely are a few 

 plants of cacao found on the banks of the Bio de Valencia ; 

 the rest of the plain is bare, and destitute of vegetation. 

 This appearance of sterility is here attributed, as it is every- 

 where in the valleys of Aragua, to the cultivation of indigo ; 

 which, according to the planters, is, of all plants, that which 

 most exhausts (cansa) the ground. The real physical causes 

 of this phenomenon would be an interesting inquiry, since, 

 like the effects of fallowing land, and of a rotation of crops, 

 it is far from being sufficiently understood. I shall only 

 observe in general, that the complaints of the increasing 

 sterility of cultivated land become more frequent between 

 the tropics, in proportion as they are near the period of 

 their first breaking-up. In a region almost destitute of 

 herbs, where every plant has a ligneous stem, and tends to 

 raise itself as a shrub, the virgin soil remains shaded either 

 by great trees, or by bushes; and under this tufted shade it 

 preserves everywhere coolness and humidity. However 

 active the vegetation of the tropics may appear, the number 

 of roots that penetrate into the earth, is not so great in an 

 uncultivated soil ; while the plants are nearer to each otjier 

 in lands subjected to cultivation, and covered with indigo, 

 sugar-canes, or cassava. The trees and shrubs, loaded with 



