CONCLUSION 58
CHAPTER IV. MINERAL RESOURCES--SOME GENERAL QUANTITATIVE CONSIDERATIONS 60
WORLD ANNUAL PRODUCTION OF MINERALS IN SHORT TONS 60
WORLD ANNUAL PRODUCTION OF MINERALS IN TERMS OF VALUE 62
SIGNIFICANCE OF GEOGRAPHIC DISTRIBUTION OF MINERAL PRODUCTION 63
THE INCREASING RATE OF PRODUCTION 63
CAPITAL VALUE OF WORLD MINERAL RESERVES 64
POLITICAL AND COMMERCIAL CONTROL OF MINERAL RESOURCES 65
RESERVES OF MINERAL RESOURCES 65
CHAPTER V. WATER AS A MINERAL RESOURCE 67
GENERAL GEOLOGIC RELATIONS 67
DISTRIBUTION OF UNDERGROUND WATER 68
MOVEMENT OF UNDERGROUND WATER 71
WELLS AND SPRINGS 72
COMPOSITION OF UNDERGROUND WATERS 73
RELATION OF GEOLOGY TO UNDERGROUND WATER SUPPLY 75
SURFACE WATER SUPPLIES 76
UNDERGROUND AND SURFACE WATERS IN RELATION TO EXCAVATION AND CONSTRUCTION 78
CHAPTER VI. THE COMMON ROCKS AND SOILS AS MINERAL RESOURCES 80
ECONOMIC FEATURES OF THE COMMON ROCKS 80 Granite 82 Basalt and related types 82 Limestone, marl, chalk 82 Marble 83 Sand, sandstone, quartzite (and quartz) 84 "Sand and gravel" 84 Clay, shale, slate 85 The feldspars 86 Hydraulic cement (including Portland, natural, and Puzzolan cements) 86
GEOLOGIC FEATURES OF THE COMMON ROCKS 88 Building stone 88 Crushed stone 90 Stone for metallurgical purposes 91 Clay 91 Limitations of geologic field in commercial investigation of common rocks 92
SOILS AS A MINERAL RESOURCE 94 Origin of soils 94 Composition of soils and plant growth 96 Use of geology in soil study 97