TRAVELS IN BRAZIL. 



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clay- slate is sometimes of a dirty greenish grey, and is 

 traversed by narrow strata of a compact brown iron-stone, 

 parallel to the slaty texture of the rock. This brown 

 iron-stone is often grown together with greyish white quartz, 

 which is full of little drused cavities, and gives reason to 

 suppose that quartz veins traverse the clay-slate. Gold in 

 small scales is embedded in the brown iron-stone. A clay- 

 slate, quite resembling this, is found in Bavaria, near 

 Leonhardsberg, next to Waldsassen. In it there are like- 

 wise veins of quartz, with brown iron-stone, the specimens 

 of which perfectly agree with those of Villa Rica. Only 

 these veins, like all the fossils hitherto compared with 

 those of Brazil, contain no trace of gold. The carvoeira 

 itself, which we brought from the abovementioned mine, 

 shows many differences with respect to its component 

 parts. Sometimes the proportion of manganese is greater, 

 and the colour of the mass then assumes a blackish p-reen 

 colour. Slender layers of brown iron-stone, which is often 

 already decomposed into yellow ochre, and of quartz, 

 which appears embedded in rounded grains, some- 

 times traverse the mass. Small grains of pure gold, 

 and very small acicular crystals of noble shorl, occur in 

 ' this mixture. Lastly, the mass sometimes migrates into 

 earthy, ferruginous, grey manganese-ore, which however is 

 always mixed with very fine quartz grains. In this form- 

 ation it contains many cavities, which are partly covered, 

 partly filled with a silver- white talc. In this earthy grey 

 manganese-ore there are pieces of a greyish white quartz, 

 embedded with irregular crystals of noble shorl. The 

 latter of a dark leek-green and black colour, in small and 

 very small capillary crystals, is sometimes so intimately 

 blended with the very fine-grained friable quartz, which 

 makes a part of the mass, that the latter appears massive, 

 and resembles shorl-rock. It forms single, as it seems, 

 mostly truncated, pieces, in which, again, what is called 



