First, _the great diversity of character exhibited by different sets of fissure veins which cut the same country rock_ seems incompatible with any theory of lateral secretion. These distinct systems are of different ages, of diversified composition, and have evidently drawn their supply of material from different sources. Hundreds of cases of this kind could be cited, but I will mention only a few; among others the Humboldt, the Bassick, and the Bull Domingo, near Rosita and Silver Cliff, Colorado. These are veins contained in the same sheet of eruptive rock, but the ores are as different as possible. The Humboldt is a narrow fissure carrying a thin ore streak of high grade, consisting of sulphides of silver, antimony, arsenic, and copper; the Bassick is a great conglomerate vein containing tellurides of silver and gold, argentiferous galena, blende, and yellow copper; the Bull Domingo is also a great fissure filled with rubbish containing ore chimneys of galena with tufts of wire silver. I may also cite the Jordan, with its intersecting and yet distinct and totally different veins; the Galena, the Neptune, and the American Flag, in Bingham Canon, Utah; and the closely associated yet diverse system of veins the Ferris, the Washington, the Chattanooga, the Fillmore, etc., in Bullion Canon at Marysvale. In these and many other groups which have been examined by the writer, the same rocks are cut by veins of different ages, having different bearings, and containing different ores and veinstones. It seems impossible that all these diversified materials should have been derived from the same source, and the only rational explanation of the phenomena is that which I have heretofore advocated, the ascent of metalliferous solutions from different and deep seated sources. Another apparently unanswerable argument against the theory of lateral secretion is furnished by the cases _where the same vein traverses a series of distinct formations, and holds its character essentially unaffected by changes in the country rock_. One of many such may be cited in the Star vein at Cherry Creek, Nevada, which, nearly at right angles to their strike, cuts belts of quartzite, limestone, and slate, maintaining its peculiar character of ore and gangue throughout. This and all similar veins have certainly been filled with material brought from a distance, and not derived from the walls. LEACHING OF IGNEOUS ROCKS. The arguments against the theory that mineral veins have been produced by the leaching of superficial _igneous_ rocks are in part the same as those already cited against the general theory of lateral secretion. They may be briefly summarized as follows: