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neither numerous nor very good ; the best comes from the 
Aroa mines, the small granular pyrites appears to be most 
abundant in a decomposing gneissoze rock. 
The galenas are from mines at Los Teques, Aroa, and 
Campano, several are pseudomorphou s crystals in filmy 
aggregations, interesting specimens for the mineralogist. 
The iron ores include specimens of pyrites (mundic) which 
in Venezuela appears to be as abundant as in most palaeozoic 
regions, ten of the samples are rich, and would be profit- 
able if the cost of mining is not too expensive at Barquis- 
imeto, Caracas, and the Aroa mines. 
The haematites include specular, micaceous, and red iron 
ores, all comparable to the best European ores. The lim- 
nites comprise bog-iron ore of recent formation and a brown 
amorphous ore. The siderites include an aggregation of 
tabular crystals from Caracas, probably a carbonate of 
protoxide of iron valuable in making steel, and massive 
clay ironstones from the districts of Corui Maehate, where 
coal is also worked. The crystallised and compact magnet- 
ites come from the same place. A thin vein of brown 
siliceous ironstone has its surfaces covered with minute 
fragments of clear quartz, singular and beautiful under the 
microscope. 
The carbonaceous minerals are coals, graphite, sulphur, 
asphaltum and/petroleum. The coals are from Nuevo Mundo, 
where Mr. Spence has proved the existence of workable 
coals, the Island of Toas in the Lake Maraciabo, and a can- 
nel coal from Coro, with several black shales from these 
localities. These coals are undoubtedly of excellent quality, 
and from report can be worked economically ; their age is 
at present unknown from the want of any proper geological 
survey, and in the absence of fossils of any kind in the 
shales in this collection; in all probability however the 
Venezuelan coals are of true carboniferous age. 
The graphite from Caracas is an impure amorphous earthy 
