The known limits of this lode cover a space of 22,546 feet in a nearly due north and south direction (magnetic). The variation of the needle in that locality is 16½ degrees east. Upon this extensive seat of metalliferous deposits, the mines are divided into three groups: the Virginia Group, seventeen mines, with claims of 13,549⅓ feet; Gold Hill Group, nine mines, of 6,397¼ feet; American Flat Group, three mines, of 2,600 feet. The three groups of twenty-nine mines thus occupy a total length on the lode of 22,546 feet. The Comstock lode was discovered in 1859, by a pit sunk for a water hole on the ground of the Ophir mine; milling the ore began in October of the same year, but the amount of bullion taken out in 1860 is estimated at but $100,000. Since then the Comstock has become the greatest gold and silver mine in the world. To the end of 1878 the yield was estimated at $291,162,205, as follows: From 1860 to 1870 inclusive, of gold and silver together, unclassified, $102,466,240; 1871 to 1878 inclusive, gold, $88,691,498, silver, $91,278,623; 1877 and 1878, gold and silver, unclassified, $1,725,844. Making allowance for the loss by slimes and tailings, the gross contents of the lode as worked up to 1878 are estimated at $363,961,205. About 6,500,000 tons of ore have been extracted in this time, which a good authority estimates of an average value to the company of $45 per ton of 2,000 pounds.[5] ANNUAL PRODUCTION of GOLD and SILVER in the UNITED STATES from 1853 to 1880, inclusive. [From the Reports of the Director of the Mint.]