ORES — RAVINE OF TIPE. 135 



found the path which they had cut tlirougli the Avood, CliAP. xii. 

 they soon arrived at tlie district of resinous shrubs, Desertion of 

 where they lingered so long collecting plants that dark- guides, 

 ness surprised them as they entered the savannah. The 

 moon was uj), but every now and then obscured by 

 clouds. The guides who carried the instruments slunk 

 off" successively to sleep among the cliffs ; and it was 

 not until ten that the travellers arrived at the bottom 

 of the ravine, overcome by thirst and fatigue. 



During the excursion to the Silla, and in all their indication cf 

 walks in the valley of Caraccas, they were very attentive °'^^^ 

 to the indication of ores which they found in the gneiss 

 mountains. In America that rock has not hitlaerto been 

 found to be very rich in metals, the most celebrated 

 mines of Mexico and Peru being in primitive and 

 transition slate, trap, porphyry, graywacke, and Alpine 

 limestone. In several parts of the region now visited 

 small quantity of gold was found disseminated in veins Gold, silver 

 of quartz, sulphuretted silver, blue copper-ore, and lead- ^"gg'^"^'^'^'^ 

 glance ; but these deposites did not seem of any import- 

 ance. In the group of the western mountains of Vene- 

 zuela, the Spaniards, in 1551, attempted tlie gold mine 

 of Buria, but the works were soon given up. In the 

 vicinity of Caraccas some had also been wrought, but to 

 no great extent. In short, the mines here afforded little 

 gratification to the cupidity of the conquerors, and were 

 almost totally abandoned ; those of Arva, near San Felipe 

 el Fuerte, being the only ones in operation when Hum- 

 boldt visited the country. 



In the course of their investigations the travellers Ravine of 

 examined the ravine of Tipe, situated in that part of '^'P'^- 

 the valley which opens toward Cape Blanco. The first 

 portion of the road was over a barren and rocky soil, on 

 which grew a few plants of Argemone Mexk-ana. On 

 either side of the defile was a range of bare mountains, 

 and at this spot the plain on which the town is built 

 communicates with the coast near Catia by the valleys 

 of Tacagua and Tipe. In the former the}' found some 

 plantations of maize and plantains, and a very extensive 



