242 
ORIGIN OF SAVANNA 118. 
used to the saddle. Though their appearance is very heavy, 
they pass lightly over the most slippery turf. We first 
stopped at a spring issuing, not from the calcareous rock, 
but from a layer ot quartzose sandstone. The temperature 
was 21°, consequently T5° less than the spring of Quetepe ; ' 
and the difference of the level is nearly 220 toises. Where- 
ever the sandstone appears above ground the soil is level, and 
constitutes as it were small platforms, succeeding each other 
like steps. To the height of 700 toises, and even beyond, 
this mountain, like those in its vicinity, is covered only with 
gramineous plants.* The absence of trees is attributed at 
Cumana to the great elevation of the ground; but a slight 
reflection on the distribution of plants in the Cordilleras of 
the torrid zone will lead us to conceive that the summits of 
New Andalusia are very far from reaching the superior limit 
of the trees, which in this latitude is at least 1800 toises of 
absolute height. The smooth turf of the Cocollar begins to 
appear at 350 toises above the level of the sea, and the 
traveller may contrive to walk upon this turf till he reaches 
a thousand toises in height. Farther on, beyond this band 
covered with gramineous plants, we found, amidst peaks 
almost inaccessible to man, a small forest of cedrela, javillo,t 
and mahogany. These local circumstances induce me to 
think that the mountainous savannahs of the Cocollar and 
Turimiquiri owe their existence only to the destructive cus- 
tom practised by the natives of setting fire to the woods 
when they want to convert the soil into pasturage. Where, 
during the lapse of three centuries, grasses and alpine plants 
have covered the soil with a thick carpet, the seeds of trees 
can no longer germinate and fix themselves in the earth, 
though birds and winds convey them continually from the 
distant forests into the savannahs. 
* The most abundant species are tlie paspalus ; the Andropogon fasti- 
glatum, which forms the genus Diectomis of M. Palissot de Beauvais ; 
and the Panicum olyroldes. 
t Huras crepitans, of the family of the euphorbias. The growth of 
its trunk is so enormous, that M. Bonpland measured vats of javillo 
wood, 14 feet long and 8 wide. These vats, made from one log of wood, 
are emplcved to keep the guarapo, or juice of the sugar-cane, and the mo- 
lasses. The seeds of javillo are a very active poison, and the milk that 
issues from the petioles, when broken, frequently produced inflammation 
Vi our eyes, if by chance the least quantity penet rated under the eyends 
