nes. 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:

1. Thousands of mineral veins in this and other countries occur in
regions remote from eruptive rocks. Into this category come most of
those of the eastern half of the Continent, viz., Canada, New England,
the Alleghany belt, and the Mississippi Valley. Among those I will refer
only to a few selected to represent the greatest range of character,
viz., the Victoria lead mine, near Sault Ste. Marie, the Bruce copper
mine on Lake Huron, the gold-bearing quartz veins of Madoc, the Gatling
gold vein of Marmora, the Acton and the Harvey Hill copper mines of
Canada, the copper veins of Ely, Vermont, and of Blue Hills, Maine, the
silver-bearing lead veins of Newburyport, Mass.; most of the segregated
gold veins of the Alleghany belt, the lead veins of Rossie, Ellenville,
and at other localities farther South; the copper bearing veins of
Virginia, North Carolina, and Tennessee; the veins carrying
argentiferous galena in Central Kentucky and in Southern Illinois; the
silver, copper, and antimony veins of Arkansas; and the lead and zinc
deposits of Missouri and the Upper Mississippi.

In these widely separated localities are to be found fissure,
segregated, and gash veins, and a great diversity of ores, which have
been derived, sometimes from the adjacent rocks--as in the