Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/448

338 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 9, the Corinna consists of decomposed schist. On the hill south-east of Niieva Providencia there are numerous abandoned " barrancos " or pits sunk to work the Tigre lode. I was told that its strike is IST. 30°E., and that it is about a foot wide and very rich. The country is a hard, dark-greenish rock.

In Nueva Providencia numerous blocks of loose quartz contain- ing gold are lying about in one part of the town, probably derived from a lode which crops out here, and the Prefect of the Depart- ment of the Yuruari has been working a lode in his garden just east of the town. In the San Pelipe property, to the south of the town, several lodes are said to have been discovered.

The Peru lode, situated near the source of a branch of the Mu- cupia brook, runs E. 5° IN', and dips south at 60°. It is 2 feet wide, and consists of quartz, with brown oxide of iron, the usual blackish streaks, talc, and visible gold.

In another little, neighbouring valley are the Potosi workings. In one of the adits driven into the hillside there are two east and west lodes, dipping 55° in opposite directions, the level being driven just below the intersection. The stuff is very similar to that of Peru, and there is no difficulty in finding visible gold.

The Chile lode lies about a quarter of a mile south of Potosi, and, after Callao, is at present the most important in the Caratal district. The Chile main lode runs about E. 10° N. to E. 15° N., and dips south at 45° to 60°. It varies in width from 2 feet to 6 feet. It consists mainly of quartz, with brown oxide of iron, the blackish streaks, talc, a white earthy mineral like kaolin, and visible gold. In many pieces of stuff from this lode there are cubical cavities lined with gold as if they had been plated, or containing leafy gold ; sometimes also the cavity is filled with brown oxide of iron in which specks of gold are visible. The cavities seem to be due to the decomposition of iron pyrites which originally filled them. The coarse gold which is found at Callao does not occur at

Fig. 1. — Plan of Chile Lodes.

Chile. To the west the Chile lode splits up into at least three branches, as is shown on the accompanying diagram-plan (fig. 1).