| OCR Text |
Show 63 mixed veins. The mountains are largely made up of Silurian limestone. Encrinites are found in this in great numbers. Some spirifers also occur, but other fossil- shells are rare. Dikes of intrusive rock, such as diorite and syenite, abound, and the strata are much displaced, in some cases standing on edge. On the east side of the main peaks there are large foot- hills entirely made up of syenite, evidently of an eruptive character. Quartz- ledges, with stetefeldtite and chloride of silver, traverse this rock. This eruptive syenite consists chiefly of oiigoclase, orthoelase, and hornblende, with quartz in small quantities. Signs of former glacial action are evident. The ores are worked by the smelting process. The average yield is 400 pounds of lead and 60 ounces of silver per ton of galena, while the argentiferous copper ores give 75 ounces of silver per ton. On the west side of the main peak the ores are galena, massicot, cerussite, anglesite, and mimetite, accompanied by sulphide of arsenic. Gerargyrite and argentite occur, and nuggets of gold, in value from $ 60 to $ 100, have been found. On the east side of the peak the ores are gray copper, stromeyerite, and copper glance, with some native silver and argentite. This ore, especially of the Buena Suerte lode, contains gold to the amount of $ 20 to $ 30 per ton. Iron, arsenic, antimony, zinc, lead, and copper are the base metals. The principal mines west of Cerro Gordo Peak are the Union, whose lode is 12 feet in width, with a tunnel 600 feet long and a shaft 800 feet in depth; the Santa Maria, 6 feet in width, with which is connected the Omega Tunnel, 900 feet long, and a shaft 300 feet deep; the San Felipe, with a vein from 1 to 6 feet in width; the Ignacio, a wide quartz ledge, containing argentiferous copper glance and galena; and the Jefferson, with the Buena Vista Tunnel, 800 feet long. The ore of the latter lode is 35 per cent, lead and yields 80 ounces of silver per ton. It contains a number of " chimneys of soft ore;" carbonate of lead and massicot. East of the peak are the Belmont, Wittekind, and Buena Suerte lodes. The ledge of the latter is from 2 to 5 feet thick, and contains bodies of ore which assay from $ 150 to 9400 per ton. Its walls are slicken-sided. It has four tunnels, averaging 150 feet in length. The Potosi Tannel, 4,400 feet long, to be completed in two years, at a cost of $ 97,000, is intended to connect with the leading mines at Gerro Gordo. Altogether, about $ 5,000,000 of silver have been exported from this district since the introduction of machinery, some seven years ago. There are two smelting- furnaces; of simple construction, but no mills. The reduction- works have a working capacity of 8 tons. The lead and silver of the bullion are not separated here, but are sent elsewhere for cupellation. Great loss is sustained in smelting the ores, as hardly two-thirds of the assay yield is obtained in silver. Mining expenses will average as follows: Extracting the ore, per ton, 850 to $ 100; labor, per diem, $ 4; running a tunnel on main vein, $ 10; sinking a shaft, $ 20; running a drift, $ 5. Owen's Valley and the San Joa-qnin Valley are the sources of supply for hay ($ 60 per ton) and grain, ( 5 cents per pound.) Some pifion and juniper timber grows on the Inyo range. There is no pine nearer than the Sierra Nevada, 60 miles distant. The water is supplied from a source 4 miles away, from which three powerful engines produce 10,000 gallons a day, lifting it 2,200 feet. The inhabitants of the district number 500, in addition to 100 Pah- Ute Indians. There is no game in the vicinity. |
