CHAPTER X. COPPER, LEAD AND ZINC MINERALS 197

COPPER ORES 197 Economic features 197 Geologic features 199 Copper deposits associated with igneous flows 200 Copper veins in igneous rocks 201 "Porphyry coppers" 203 Copper in limestone near igneous contacts 204 Copper deposits in schists 204 Sedimentary copper deposits 205 General comments 206

LEAD ORES 209 Economic features 209 Geologic features 211

ZINC ORES 213 Economic features 213 Geologic features 216