ng his own
limitations (pp. 92-94), but no attempt has been made to cover the
variety of such questions that may come up. It is safe to assume that no
special ethical code can be made sufficiently comprehensive, detailed,
and elastic to cover all the contingencies which are likely to be met in
the practice of economic geology; nor is it likely that any such code,
if attempted, would be any improvement on the spirit of the Golden Rule.
Simple decency and common sense in their broader implications are
essential to the practice of the profession.

INDEX

Abrasives, 267-270, 397

Abyssinia, potash, 112

Adams, Frank D., 367

Adirondacks, New York, graphite, 282
iron ores, 160, 162, 163, 171
phosphate from magnetic ores, 105-106
use of magnetic surveys in tracing iron rocks, 317

Ad valorem method of valuation of mineral deposits, 331-335

Africa, bauxite, 242
coal, 116
cobalt, 255
copper, 197-198, 205
tin, 260
_See also_ South Africa; North Africa; East Africa; West Africa.
Alabama, bauxite, 243, 245
graphite, 281
iron, 52-53, 160, 162, 163, 166-167

Alaska, antimony, 248
copper, 36, 41, 47, 49, 199, 200-201
gold, 222, 224, 229
silver, 234
tin, 261, 262

Algeria, antimony, 247, 248
gypsum, 283
iron, 156, 160, 161, 194
petroleum, 128
phosphates, 104, 105, 106
_See also_ North Africa.

Almaden, Spain, mercury ores, 256-257, 259

Alsace, potash, 111-113

Alsace-Lorraine, coal and iron of, under Peace Treaty, 401-402

Aluminum Company of America, 243

Aluminum ores, 241-246, 397
_See also_ Bauxite.

Alunite, 39, 41-42, 112, 114, 230

Anaconda, Montana, arsenic production, 250

Anaconda Copper Mining Company, manufacture of phosphate, 105
use of geology in development and exploration, 326-327

Anamorphism, defined, 27, 57

Anamorphism of mineral deposits, 26, 57-58

Anhydrite, occurrence in gypsum deposits, 284-285

Anticlines, occurrence of oil in, 141-142, 147-148

Antimonial lead, 246

Antimony ores, 246-249, 398

Apex law, 349-350, 353

Aplites, 35

Appalachians, barite, 274
bauxite, 245
graphite, 282-283
petroleum, 132, 135
pitchblende, 266
pyrite, 108
tin, 262
_See also_ under individual states.

Argentina, borax, 275
mica, 286
petroleum, 128
tungsten, 183

Arizona, asbestos