304 Relations of Trap-Bocks with Ores of Copper. 



act a somewhat important part in the filling up. The re- 

 positories of Blanca, Arrieta, &c., appear to be in similar 

 conditions with respect to position, and identical in regard to 

 composition. 



The re-opening of the mines of Cuba dates from 1833. It 

 was commenced by English companies, among which that 

 of Cobre devoted a capital of ten millions of francs to the 

 works. Among the indications which drew the attention of the 

 English companies to these mines, w^hich, in reality, are less 

 prosperous than important in their produce, we must no 

 doubt place in the first rank the traces of the ancient works, 

 and the tradition by which Cobre was celebrated as formerly 

 furnishing copper to the natives, and having, in former times, 

 even given employment to the Conquisfadores. These are 

 circumstances that would have acted on any mind ; but no- 

 thing had such weight in the eyes of the English miners, as 

 the existence of numerous ridges, iVaffleurements, composed 

 o^ gossan. The first captains of the mines who came from 

 Cornwall to Santiago de Cuba, and among others Captain 

 Reynolds, could not find expressions too strong to express 

 their admiration at the sight of these masses of gossan, iden- 

 tical with those of Cornwall, but of greatly superior thick- 

 ness. The native copper, oxidulated and black peroxide, 

 found in the gossan, confirmed this first opinion, and they 

 did not hesitate to commence mining operations on a vast 

 and expensive scale. It is in this way that the natives of 

 every country assign a first rank to the indications recog- 

 nised in their own district. These Ghapeaux de fer would 

 assuredly have been properly valued by others ; but they 

 would not have induced them to adopt such a decided mode 

 of action. 



The works, continued for fifteen years with increasing ac- 

 tivity, have affbrded valuable instruction, which shews what 

 a degree of uniformity exists in the laws which regulate the 

 position, the allure, and the composition of metalliferous re- 

 positories. In a geognostic point of view, we again find 

 there repositories of contact, and the influence of trappean 

 rocks. With respect to composition, we find the sulphuretted 



