CABO BLANCO. 
385 
at La Guayra. A ravine, called the Quebrada de Tipe, 
descends from the table-land of Caracas towards Catia. A 
plan has long been in contemplation for making a cart- 
road through this ravine and abandoning the old road 
to La Guayra, which resembles the passage over St. Go- 
thard. According to this plan, the port of Catia, equally 
large and secure, would supersede that of La Guayra. Un- 
fortunately, however, all that shore, to leeward of Cabo 
Blanco, abounds with mangroves, and is extremely ur 
healthy. I ascended to the summit of the promontory, 
which forms Cabo Blanco, in order to observe the passage 
of the sun over the meridian. I wished to compare in the 
morning the altitudes taken with an artificial horizon and 
those taken with the horizon of the sea ; to verify the ap- 
parent depression of the latter, by the barometrical mea- 
surement of the hill. By this method, hitherto very little 
employed, on reducing the heights of the sun to the same 
time, a reflecting instrument may be used like an instru- 
ment furnished with a level. I found the latitude of the 
cape to be 10° 36' 45"; I could only make use of the 
angles which gave the image of the sun reflected on a 
plane glass; the horizon of the sea was very misty, and the 
windings of the coast prevented me from taking the height 
of the aim on that horizon. 
The environs of Cabo Blanco are not uninteresting for 
the study of rocks. The gneiss here passes into the state 
of mica-slate,* and contains, along the sea-coast, layers of 
schistose chlorite. 4 In this latter I found garnets and 
magnetical sand. On the road to Catia we see the chlo- 
ritic schist passing into hornblende schist.J All these for- 
mations are found together in the primitive mountains of 
the old world, especially in the north of Europe. The sea 
at the foot of Cabo Blanco throws up on the beach rolled 
fragments of a rock, which is a granular mixture of horn- 
blende and lamellar feldspar. It is what is rather vaguely 
called primitive qrunstein. In it we can recognize traces 
of quartz and pyrites. Submarine rocks probably exist near 
the coast, which furnish these very hard masses. I have 
* Glimmerschiefer. f Chloritschief«r . 
* Hornblendscliiefer. 
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VOL. I. 
