CONTENTS 
PART I 
[INTRODUCTION 
CHAPTER I 
PAGE 
THE Score or EcoNoMic GeoLogy AND THE SEARCH FOR ORES 1 
Definitions of Mineral, Ore-grade, and Metal, The Sporadic Dis. 
tribution of Ores, Prospecting, Structure of Lodes. The 
term Reef, 
CHAPTER II 
THE FORMATION OF DEPOSITS OF USEFUL MINERALS ® . 
History of Study of Ores. Structure of the Earth ; its Barysphere. 
Source of the Metals in Ores. Ore Formation in Relation to 
Igneous Rocks. The Ore Zone, Plutonic, Juvenile, and 
Magmatic Waters. Magmatic Ores. Lode Deposition—Hyda- 
togenesis, Propylitization, and Pneumatolysis. Lode Structure 
and Depth of Ore Formation. Ore Sequence in Depth. Ore 
Shoots and Ore-bodies. Efflorescent Minerals. Bedded 
Mineral Deposits. Alluvial Ores and Placers. Microscopic 
Study of Ores. Chief Mineral Deposits due to Segregation, 
PART II 
ORE DEPOSITS 
CHAPTER IIT 
ORES OF GoLD . . . 
Gold and its Qualities. Gold in Sea-water, Gold Lodes and Ig- 
neous Rocks. Classification of Gold Ores— Primary Ores. 
Gold-quartz Fissure Lodes, California, Ballarat, Mysore, 
Volcanic Fields—Rocky Mountains and New Zealand. Pneu- 
matolytic Ores—Cripple Greek and Passagem, Brazil. Iso. 
lated Gold-quartz Veins—Saddle- and Ladder-lodes. Im- 
pregnations and Replacements — Rhodesia, Homestake, 
Alaska, and Porcupine. The Goldfields of West Australia. 
Secondary Ores—Mount Morgan, Queensland, Alluvial 
Goldfields—Placers ; Deep Leads, The Rand Banket. 
Morro Velho. 
2