COMPARISON OF LISTS OF MOST ABUNDANT ROCKS AND MINERALS WITH
COMMERCIAL ROCKS AND MINERALS 18

THE ORIGIN OF COMMON ROCKS AND MINERALS 18
Igneous processes 19
Igneous after-effects 19
Weathering of igneous rocks and veins 20
Sedimentary processes 22
Weathering of sedimentary rocks 23
Consolidation, cementation, and other sub-surface
alterations of rocks 24
Cementation 24
Dynamic and contact metamorphism 25

THE METAMORPHIC CYCLE AS AN AID IN STUDYING MINERAL DEPOSITS 27

CHAPTER III. SOME SALIENT FEATURES OF THE GEOLOGY
AND CLASSIFICATION OF MINERAL DEPOSITS 29

VARIOUS METHODS OF CLASSIFICATION 29

NAMES 31

MINERAL DEPOSITS AS MAGMATIC SEGREGATIONS IN IGNEOUS ROCKS 34

MINERAL DEPOSITS WITHIN AND ADJACENT TO IGNEOUS ROCKS,
WHICH WERE FORMED IMMEDIATELY AFTER THE COOLING AND
CRYSTALLIZATION OF THE MAGMAS THROUGH THE AGENCY OF HOT
MAGMATIC SOLUTIONS 36
Evidence of igneous source 37
Possible influence of meteoric waters in deposition of ores
of this class 41
Zonal arrangement of minerals related to igneous rocks 42
The relation of contact metamorphism to ore bodies of the
foregoing class 45

SECONDARY CONCENTRATION IN PLACE OF THE FOREGOING CLASSES OF
MINERAL DEPOSITS THROUGH THE AGENCY OF SURFACE SOLUTIONS 46

RESIDUAL MINERAL DEPOSITS FORMED BY THE WEATHERING OF
IGNEOUS ROCKS IN PLACE 50

MINERAL DEPOSITS FORMED DIRECTLY AS PLACERS AND SEDIMENTS 51
Mechanically deposited minerals 51
Chemically and organically deposited minerals 52

SEDIMENTARY MINERAL DEPOSITS WHICH HAVE REQUIRED FURTHER