390 
CITT OF CARACAS. 
tlie capital, situated three hundred toises beloiv, in a vaile* 
luxuriantly plauted with coffee and European fruit-trees. 
Travellers are accustomed to halt near a fine spring, known 
by the name of Fuente de Sanchorquiz, which flows down 
from the Sierra on sloping strata of gneiss. I found its 
temperature 16'4° ; which, for an elevation of seven hundred 
and twenty-six toises, is considerably cool, and it would 
appear much cooler to those who drink its limped water, if, 
instead of gushing out between La Cumbre and the tempe- 
rate valley of Caracas, it were found on the descent towards 
La G-uayra. But at this descent on the northern side of 
the mountain, the rock, by an uncommon exception in this 
country, does not dip to north-west, but to south-east, which 
prevents the subterranean waters from forming springs 
there. 
We continued to descend from the small ravine of San- 
ehorquiz to la Cruz de la Guayra, a cross erected on an opeu 
spot, six hundred and thirty-two toises high, and thence 
(entering by the custom-house and the quarter of the Pas- 
tora) to the city ot Caracas. On the south side of the 
mountain of Avila, the gneiss presents several geognostical 
phenomena worthy of the attention of travellers. It is tra- 
versed by veins of quartz, containing cannulated and often 
articulated prisms of rutile titanite two or three lines in 
diameter. In the fissures of the quartz we find, on breaking 
it, very thin crystals, which crossing each other form a kind 
of network. Sometimes the red schorl occurs only in den- 
dritic crystals of a bright red.* The gneiss of the valley of 
Caracas is characterized by the red and green garnets it con- 
tains ; they however disappear when the rock passes into 
mica-slate. This same phenomenon has been remarked by 
Von Buch in Sweden ; but in the temperate parts ol Europe 
garnets are in general contained in serpentine and mica- 
slates, not in gneiss. In the walls which enclose the gardens 
of Caracas, constructed partly of fragments of gneiss, we 
find garnets oi a very fine red, a little transparent, and very 
difficult to detach. The gneiss near the Cross of La 
Gruayra, halt a league from Caracas, presented also vestiges of 
* Especially below the Cross of La Gvayra, at 594 toises of absolute 
elevation. 
