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The rock on both sides of the lode is gold-bearing, and is evidently, as well as the real lode, formed of the debris of old quartz and granites. Talcose flakes are frequent, and in some places it seems to be clearly gneiss.
I noticed also some contorted, highly inclined talcose schists, full of small quartz veins, generally running between the laminae of the schists. Probably the conglomerates had been produced by the wearing down of these schists. We passed through two Indian towns the first Yalaguina, the second Totagalpa.
I passed a pit on the western flank; the winch had been removed, and my people found it impracticable: we descended to it by cut steps and followed a cornice, mainly artificial, for a short distance to where its mouth opened. This hole had been sunk 70 to 80 feet deep in the talcose stone; and it would have been far easier and better to have driven galleries and adits into the face of the rock.
I could perceive no trace of a metallic vein, so thoroughly had it been worked out, but scattered over the hillside with schist, talcose slate, and fragments of quartz, was a great deal of scoriae, showing that metal of some kind had been excavated, and that the smelting had been done on the spot.
The numerous travellers in this country, have all been greatly surprised at the depth to which the gneiss and other granitic rocks, as well as the talcose slates of the interior, have been decomposed. Benza describes granitic rock, "Madras Journal of Literature" etc.
That of the Green Eyed Monster now thoroughly oxidized as far as penetrated forms a sheet from twenty to forty feet in thickness, consisting of ferruginous, sandy, or talcose soft material carrying from twenty to thirty dollars to the ton in gold and silver.
On some of them the coal-beds form part of the cliffs along the shore; on others, copper is found in a chlorite and talcose slate. The latter is more particularly the case with Luzon, and the same formation extends to Mindoro. Much iron occurs on the mountains. These are, occasionally, obtained by the Spaniards in their excursions into the interior against these bands.
It was called by the Romans, from the use made of it in fabricating measures of weight, lapis æquipondus, and from its supposed efficacy in the cure of diseases of the kidneys lapis nephriticus. Fabreti says that it got the name of lapis Lydius from the locality from which it was believed to have come. It is a kind of nephrite or jade, a mineral which usually occurs in talcose or magnesian rocks.
Notwithstanding a general uniformity in the aspect of Plutonic rocks, we have seen in the last chapter that there are many varieties, such as syenite, talcose granite, and others.
At the entrance of the Quebrada Seca we remarked great masses of primitive saccharoidal limestone, tolerably fine grained, of a bluish tint, and traversed by veins of calcareous spar of dazzling whiteness. The aspect of the rock is very singular in those places where thin plates of black ampelite alternate with thin, sinuous, and satiny plates of a talcose slate as white as snow.