ee 
216 GEOLCGY OF PART OF CUBA. 
during an ineffectual search for gold: and the denouncement of San Fernando was then 
commenced to be worked as a copper mine. Several others were soon after discovered ; 
and legal possession of them was secured, according to the usual Spanish forms, to the pro- 
prietors, by authority of the local government. Among the earliest of these was the mine 
of San Augustin, followed by the Buena Isabela, in 1835. Stimulated by the success 
which attended the working of the Cobre mines, to the south, the mineral researches 
were here prosecuted with activity, and not a savana in our district escaped a strict ex- 
ploration. The principal copper Jode at Sabana Vieya was discovered in 1835. Careful 
examination was made of this denouncement in the following year, and the outcrops of 
eight copper lodes were traced, within the breadth of a few yards. Of all these we shall 
shortly speak; but, necessarily, with brevity. 
Character of the Copper Lodes.—It has been stated that the mineral veins of this dis- 
trict occur in stratified rocks, the most prevalent of which is serpentine. We have 
shown that these lodes were contemporaneous with those formations: that is to say, they 
do not traverse any rocks, but are interstratified with them. Wheresoever our examina- 
tions extended, we found that these lodes have regular walls, containing much silicate 
and carbonate of magnesia; and having polished sides or surfaces. Further, we demon- 
strated that these copper lodes maintain nearly uniform directions, parallelism, and incli- 
nations, that is to say, the prevailing course is about I. N. E., and the average dip to 
the south is about sixty-five degrees. As is usual with cupriferous veins, the surface 
ores, comprising under that head those within fifty or eighty feet below the outcrop, 
materially differ from the mineral matter at a greater depth. The most prominent varie- 
ties of these are the silicates, the carbonates, the oxides, and the sulphurets. Native 
copper is not unfrequent; but not lower than thirty yards from the outcrop. In the 
mine of San Fernando it occurs in masses of from ten to two hundred or more pounds’ 
weight. 
San Fernando.—This mine has heretofore been worked upon the old Mexican system, 
if system that can be called, which consists of an intricate labyrinth of shafts, slopes, 
drifts, and holes; winding in most inexplicable confusion, without reference to ventilation 
or drainage. Subsequently, under better advice, the lode has been intersected by an adit. 
The ore is a sulphuret, of a dark bronze green, inclining to a bluish gray colour, rich 
in copper, and intermixed with excellent gray and vitreous copper.* 
Socorro, discovered in 1831, and San Antomo: the latter has a good lode of rich ore. 
San Juan, and Mina Innocentes: all these have Spanish owners, and have made very little 
progress. 
Olivo.—A Boston undertaking. Its adit was commenced in 1836; a good lode struck 
in 1837, at two hundred and forty feet below the summit of the savana. The magnesian 
ground in which this lode occurs is soft and favourable for mining. 
San Augustin.—An American undertaking. The mine is eleven miles from the Em- 
barcadero or landing place of the Gibara river. Course of the lode EK. N. E.—dip 60° to 
* Yielding 33.60 per cent. T. G. Clemson. Weaker surface ore below an average 18.56. 
+ Varying from twenty-three to twenty-seven per cent. of copper. 
