In the Province of _Mendoza_ there are mines of copper, silver-bearing galena, gold-bearing quartz, coal, alabaster, slate, and marble, and wells of petroleum; in the Province of _San Juan_, of gold-bearing quartz, silver, copper, antimony, coal, sulphur, and amianthus.[86] In view of the development which this region may undergo through the exploitation of the coal-measures, the Great Western Railway has decided to construct a branch line as far as the coal mines of Salagasta (Mendoza). [Footnote 86: Amianthus——the best quality of asbestos.——[TRANS.]] The Province of _La Rioja_ has been known for a long time for its rich mines of metallic silver, and also for its copper mines, whose ores contain a high percentage of gold and silver; and for its gold “placer” mines. It is to facilitate the working of these mines that the aerial cable-way is being constructed, which will unite Cerro de Famatina and the mining centre of Chilecito with the railways. Here, as everywhere, skilled miners are somewhat scarce. The Province of _Catamarca_, the centre of the Capillitas mining country, possesses copper mines with a high percentage of silver and gold, which have been worked for more than thirty years. These mines, which are, it appears, very rich in minerals, have been acquired by a foreign company, and will be the object of an important enterprise; here, too, an aerial cable-way will be built to transport the ore from the mines to a lower level. There are also in this region two important smelting works; “Le Pilcian” and “La Constancia,” which are buried in the depths of the forests of carob-trees, which furnish abundant fuel. In other parts are found surface veins of copper, silver-bearing galena, bismuth, antimony, mica, gold-bearing quartz, as well as “placer” mines and coal-measures. The Provinces of _Salta_ and _Jujuy_, which possess rich veins of auriferous quartz, argentiferous galena, copper, borate of lime, lignite and petroleum, are famous for the gold obtained from the streams that descend from their mountains. Undertakings have been formed with foreign and native capital, and profitable results are expected. The extension of the Argentine railways to Bolivia will still further develop the exploitation of mining districts all through this region. In former times silver mines were worked in the Province of _Tucuman_. In Aconquija also we find mines of copper which must be a continuation of those of Catamarca. The Provinces of _Córdoba_ and _San Luis_, besides ascertained veins of gold-bearing quartz, galena and copper, contain mines of manganese and wolfram, and well-known quarries of marble, and of onyx, both green and of other shades.