114 



The collection of minerals acquired by Mr. J. M. Spenco 

 during his residence at Caracas, and on several journeys 

 along tlie coast, came from the provinces of Barcelona, Boli- 

 var, Carabobo, and Coro, with a few obtained from the 

 reoions of the River Orinoco and Lake Maracaibo. The 

 collection contains gold in quartz of very rich character, 

 argentiferous ores, green and blue carbonates of copper, 

 copper pyrites, galena, iron ores of various kinds, carbona- 

 ceous minerals, calcites, silicas, and rock specimens of gneiss, 

 mica, talc schists, kaolin, hornblendic rocks, and serpentine 

 with a few imperfect fossil and silicified woods. 



The gold quartz of the richest kind, came from the Pro- 

 vince of Guayana, where vast regions of auriferous rocks 

 occur ; and where also gold is found in small grains, flakes, 

 and nuggets of all sizes from an ounce to many pounds 

 weight, in a clay from two to eight inches thick, as well as 

 in a red peroxidated iron earth, both probably alluvial 

 drifts. The quartz veins are richly impregnated with gold 

 in crystals and strings, as may be seen in specimens in the 

 collection. Other specimens of the gold rocks come from 

 the Isle of Aruba, and Loro Estado, Tacasumino. 



The argentiferous ores are galenas and cupiferous, and 

 are not of very great richness ; they are from La Guaira^ 

 Cumana, and* Coro, where decomposed galenas are worked 

 for silver. 



The copper ores include 20 specimens from mines that 

 have been worked with profit, one of which, the Aroa mines 

 in the province of Yaracui, is the most famous for the supe- 

 rior richness of its carbonates. The specimen of cuprite from 

 this mine or Quebrada has some long and beautiful crystals 

 of olivenite with cubes of strontian, and from Aragua are 

 specimens of pyrargyrite or red silver ore; others from 

 Caracas, Coro, and the river Tui, include malachites and a 

 native sulphate of copper, probably a crystallisation from 

 the waters issuing from the mines. The chalcopyrites are 



