The vapors contained silex, quartz and whatever else was vaporized and
suspended therein. After the atmosphere had cooled it deposited on the
earth what it contained when heated. Much of the sedimentary beds built
upon the Laurentian and older rocks were simply precipitated from the
annular system.
Iron and sulphur existed in the upper ocean as metallic and mineral
salts. In the cooling process the heavier minerals and metals would
necessarily locate nearest the earth and be the first to fall. True
they were disseminated to a certain extent throughout the system.
Iron and other heavy metals formed beds in the sea bottom. Iron from
Iron Mountain, Mo., and Pilot Knob, also lead and copper ores are
in the Laurentian rocks. These rocks are aqueous or sedimentary.
The annular matter fell but in small part in equatorial regions, but
largely in temperate and frigid zones.
It is folly to suppose that all the matter of aqueous beds were
deposited from previous aqueous beds by denudation. How were subsequent
lime deposits made from silicious Archaean beds? Denudation has
taken place in all ages, and a fall and precipitation of exotic
matter--tellurio-cosmic matter--aided in the work.