THE SOMBRERO PALM. 
32 
high. It is probabty a new species of the genus corypbs; 
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 boeome 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 appeal’, the number 
of roots that penetrate into the earth, is not so great in an 
uncultivated soil ; while the plants are nearer to each other 
in lands subjected to cultivation, and covered with indigo, 
sugar-canes, or cassava. The trees and shrubs, loaded with 
